Examination of the hypopharynx predicts ease of laryngoscopic visualization and subsequent intubation: a prospective study of 665 patients. To determine (a) whether the ability to visualize a patient's airway preoperatively correlates with the ability to visualize his or her larynx during laryngoscopy and (b) whether the presence of certain anatomic characteristics allows anesthetists to predict difficult laryngoscopic visualization and intubation. Observational. Patients were categorized into two groups: those who had one or more physical characteristics to alert an anesthetist to the possibility of difficult intubation (obesity, overbite, short neck, or decreased neck/jaw mobility) and those with none of these characteristics. University-affiliated hospital. Six hundred sixty-five patients scheduled for general anesthesia and requiring endotracheal intubation. Patients were between the ages of 18 and 88 years, with body weight ranging from 21 kg to 141 kg. Preoperatively, the anesthetist obtained the best view of the hypopharynx by having the patient extend the tongue and phonate. The airway was then categorized into one of three classes by the ability to see the tonsillar pillars and uvula (Class A, best view--all four tonsillar pillars and uvula seen; Class B, part of the pillars and uvula seen; Class C, worst view--pillars not seen and uvula partially or not seen). After induction, the same anesthetist graded laryngeal visibility into one of four groups depending on his ability to see the patient's epiglottis and vocal cords. Patients with one or more clinical clues were more likely to have poor visualization of the hypopharynx and, in turn, poor laryngoscopic visualization of the glottis. Patients who had a Class A airway tended to have easy laryngoscopic visualization and were relatively easy to intubate. Conversely, patients with no clinical clues and a Class C airway had poor glottic exposure. Our study confirms work showing that the ability to visualize structures of the hypopharynx is a good predictor of subsequent glottic visualization during laryngoscopy and of ease of intubation.


Alkalinization of mepivacaine does not alter onset of caudal anesthesia. To determine the effect of alkalinization of mepivacaine on onset of caudal anesthesia. Randomized, blind study. Colon-Rectal Surgery Service of the Tertiary Center at Cleveland Clinic Foundation. Young, healthy adults undergoing anal surgery. Addition of bicarbonate (study group) or saline (control group) to mepivacaine. At the onset of sacral anesthesia, demographics were measured. A slightly faster onset was found in the study group (4.28 vs. 6.08 minutes), but this was not statistically significant. Alkalinization of mepivacaine does not significantly accelerate the onset of caudal anesthesia.


Hemodynamic and respiratory effects of transtracheal high-frequency jet ventilation during difficult intubation. To evaluate the hemodynamic and respiratory effects of percutaneous transtracheal high-frequency jet ventilation (HFJV) during difficult intubation using fiberoptic bronchoscopy under general anesthesia. Prospective study. Surgical patients scheduled for general anesthesia at the Medical College of Virginia Hospital. Eight patients with known difficult airways. Three patients had deformed facial structures. One patient had temporomandibular joint impairment. Four patients had tumors of the oral cavity with deformed upper airways. A 13-gauge cricothyroidotomy jet ventilation cannula was inserted percutaneously under local anesthesia. Anesthesia was induced with etomidate 0.2 to 0.3 mg/kg, alfentanil 15 to 20 micrograms/kg, and vecuronium 0.1 mg/kg. HFJV was started with 100% oxygen at 30 to 35 pounds per square inch of driving pressure, 100 cycles per minute, and an inspiratory/expiratory ratio of 25%. Thoracic electrical bioimpedance was used to measure cardiac index (CI) and ejection fraction (EF). Mean arterial pressure (MAP), heart rate (HR), CI, and EF were measured before induction of anesthesia; after 1 minute of HFJV, 5 minutes of HFJV, and 10 minutes of HFJV; and during positive pressure ventilation following fiberoptic intubation. Arterial blood gas samples were obtained before induction of anesthesia and after 10 minutes of HFJV. HR decreased significantly after 5 minutes of HFJV, after 10 minutes of HFJV, and after intubation (p less than 0.05). MAP decreased significantly after 10 minutes of HFJV compared with the preinduction value (mean, 97 to 71 mmHg; p less than 0.01). Although EF increased significantly following intubation, from 46% to 59%, there were no significant changes in CI. Arterial oxygen tension increased from 85 to 240 mmHg (p less than 0.05). Arterial carbon dioxide tension also increased, from 39 to 42 mmHg (p less than 0.05). Transtracheal HFJV under general anesthesia with etomidate, alfentanil, and vecuronium provided satisfactory hemodynamic conditions and pulmonary gas exchange. Percutaneous transtracheal HFJV can be used safely to manage patients with a difficult airway under general anesthesia using fiberoptic bronchoscopy.


Lidocaine blood levels following aerosolization and intravenous administration. To determine whether, following aerosolization of lidocaine for topical airway anesthesia, intravenous (IV) lidocaine produces toxic lidocaine blood concentrations. Randomized, double-blind study. University-affiliated hospital. Forty healthy patients scheduled for outpatient surgery. The patients received in a randomized, double-blind manner aerosolized lidocaine or placebo followed 10 minutes later by IV lidocaine or placebo. After completion of lidocaine or placebo aerosolization and 2 minutes following IV administration of either lidocaine or the placebo, venous blood samples were obtained. Lidocaine concentration was measured using a homogenous enzyme assay. The group receiving both aerosolized and IV placebo and the group receiving aerosolized lidocaine and an IV placebo had undetectable (less than 0.05 micrograms/ml) serum lidocaine levels. The groups that received either an aerosolized placebo or aerosolized lidocaine and IV lidocaine had similar serum lidocaine concentrations [3.34 +/- 0.46 vs. 3.24 +/- 0.55 micrograms/ml (mean +/- SEM); p greater than 0.05 by Mann-Whitney U test]. IV lidocaine can be safely administered following aerosolization of lidocaine in spontaneously breathing patients without producing toxic blood lidocaine concentrations.


Excessive atlanto-occipital flexion as a cause of complete airway obstruction following anterior cervical spine fusion. This report describes complete airway obstruction following anterior cervical fusion caused by extreme, fixed flexion of the neck in a halo device. The causes and treatment of such an airway complication are reviewed.


Should supraclavicular brachial plexus block be avoided in pregnancy? Unilateral phrenic nerve block is common after supraclavicular brachial plexus block techniques, although it is rarely symptomatic in patients without respiratory disease. A 24-weeks-pregnant woman was scheduled for a carpal tunnel release because of intractable pain. After a perivascular subclavian brachial plexus block with 30 ml of 0.33% plain bupivacaine was performed, the patient developed a right phrenic nerve block manifested by acute dyspnea and cough. No deleterious consequences followed, but surgery was canceled. Respiratory changes produced by pregnancy might compromise ventilatory reserve. Thus, we suggest avoiding supraclavicular approaches to brachial plexus block in pregnant women, since they may be as prone to developing respiratory embarrassment, secondary to phrenic block, as patients with pulmonary pathology.


Postoperative elevation of serum transaminases following isoflurane anesthesia. Halogenated inhalational anesthetics have been implicated in hepatotoxicity. Halothane hepatitis results from the biotransformation of the drug to a metabolite that binds to liver proteins, which creates a hapten, which, in turn, causes an immunologic response in the liver. Case reports of hepatic injury resulting from isoflurane, which has a decreased biotransformation compared with that of halothane, have received much criticism. We describe a patient who had elevated liver enzymes and a positive trifluoroacetyl antibody titer following an anesthetic regimen that included isoflurane.


Endothelin-1 and endothelin-3 induce chemotaxis and replication of pulmonary artery fibroblasts. The remodeling of pulmonary vessels that occurs in association with pulmonary hypertension involves, in part, thickening of the adventitia. The stimulus for this process is not understood. One explanation is that endothelial cells secrete a growth factor that expands the local population of fibroblasts by acting as a chemoattractant and mitogen. Endothelins are a family of potent newly discovered vasoactive peptides. One of these compounds, endothelin-1 (ET-1), is secreted by endothelial cells and is known to constrict pulmonary vessels. Another, endothelin-3 (ET-3), is not secreted by endothelial cells and is less potent as a pulmonary vasoconstrictor. We hypothesized that the endothelins may have the capacity both to constrict these vessels and to initiate fibroblast chemotaxis and replication. Here we investigated the effects of both ET-1 and ET-3 on the chemotaxis and replication of fibroblasts derived from pulmonary vessels. Cells were isolated from rat pulmonary arteries, cultured in medium and 10% newborn calf serum, and used between passages 2 and 5. Chemotaxis was assessed using a modified Boyden chamber with a polycarbonate filter (pore size, 8 microns) separating cells in the upper chambers from endothelin in the lower chambers. Replication was assessed both by direct cell counts and by a colorimetric assay based on uptake and subsequent release of methylene blue. Both ET-1 and ET-3 induced chemotaxis of pulmonary artery fibroblasts and did so in a dose-dependent fashion. The maxima for both peptides occurred at a concentration of about 10(-7) M, when chemotaxis was greatest for ET-1 (22 +/- 1.4 versus 14 +/- 1.8 cells/grid [mean +/- SEM], (P < 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)


Modulation of ion transport in cultured rabbit tracheal epithelium by lipoxygenase metabolites. Lipoxygenase metabolites influence ion movement and fluid balance in the airways. We studied the effects of nordihydroguaiaretic acid (NDGA), a general inhibitor of the lipoxygenase pathway, on Na+ and Cl- secretion in cultured tracheal epithelial cells from adult rabbits through short-circuit current (Isc) and radioactive tracer flux experiments. NDGA inhibition of leukotriene release in freshly isolated rabbit tracheal epithelial cells was assayed by a 3H peptidyl-leukotriene radioimmunoassay. 3 microM NDGA resulted in a 91% reduction of leukotriene release. In unstimulated cultures, Cl- secretion (furosemide-inhibited fraction of Isc) was 11.1 +/- 2.8 muamp/cm2 (n = 10) and was unchanged in the presence of NDGA (n = 10). Epinephrine-stimulated Cl- secretion increased Isc by 12.2 +/- 2 muamp/cm2 (n = 10). This stimulation was unchanged by pretreatment with NDGA (n = 10), suggesting that inhibition of the lipoxygenase pathway did not affect Cl- secretion. In unstimulated cultures, Na+ absorption (amiloride-inhibited portion of Isc) was 10.7 +/- 3.3. muamp/cm2 (n = 10) and was reduced by 79% in the presence of NDGA (n = 10), suggesting that inhibition of the lipoxygenase pathway was associated with inhibition of Na+ absorption. Radioactive tracer flux experiments supported these findings. Exogenous LTD4 (n = 7) and LTC4 (n = 7) were added to cells pretreated with NDGA, and Na+ absorption was restored to 76% and 70% of control, respectively. In addition, LTD4 (n = 4) and LTC4 (n = 4) were added to cells without prior inhibition of the lipoxygenase pathway to NDGA and resulted in an increase in Cl- secretion.(ABSTRACT TRUNCATED AT 250 WORDS)


Effect of ozone on platelet-activating factor production in phorbol-differentiated HL60 cells, a human bronchial epithelial cell line (BEAS S6), and primary human bronchial epithelial cells. Platelet-activating factor (PAF) is a phospholipid with a wide spectrum of pro-inflammatory properties. In the lung, PAF induces airway hyperresponsiveness, neutrophil sequestration, and increased vascular permeability. The alveolar macrophage and the bronchial epithelium are tissues that are exposed to inhaled ozone (O3). We studied the effect of an in vitro O3 exposure on PAF production in a macrophage-like HL60 human cell line (dHL60), a human bronchial epithelial cell line (BEAS S6), and also in primary human bronchial epithelial cells. PAF was quantified by thin-layer chromatographic separation of lipid extracts from cells radiolabeled with [3H]lysoPAF and by radioimmunoassay. In vitro exposure of dHL60 cells to 0.05 to 1.0 ppm O3 for 15 to 120 min was found to significantly increase PAF levels above air control values at all exposure levels and time points (average increase of 92%). Similarly, BEAS S6 cells grown on collagen-coated filter supports and exposed to 0.05 to 1.0 ppm O3 for 60 min released an average increase in PAF of 626% above control values. Primary human bronchial epithelial cells also demonstrated significant increases in [3H]PAF release (average increase of 289% after exposure to 1.0 ppm O3 for 60 min) compared with paired air controls. These findings suggest that some of the effects of O3 inhalation may be mediated by PAF.


Cloning of T lymphocytes from bronchoalveolar lavage fluid. We have prepared T-cell clones from bronchoalveolar lavage fluid (BALF) from four healthy, nonsmoking persons and from four patients with allergic asthma. T cells were cloned by direct limiting dilution and with the use of a fluorescent activated cell sorter with an automated cell deposition unit. T-cell clones from the blood (PB) were prepared as well. The cloning efficiencies of T cells from BALF ranged from 3 to 40% and were lower than those obtained from PB T cells (18 to 72%). The cloning conditions generated CD4+ as well as CD8+ clones. The very late antigen-4, VLA-4, was more frequently expressed on CD4+ T-cell clones from BALF than from the blood (P < 0.05). CD8+ clones from BALF were more frequently VLA-1+ than those from blood (P < < 0.01). Mitogen- and monoclonal antibody-driven proliferation of CD4+ clones showed that BALF clones were well responsive to proliferation stimuli similar to those from the blood. Analysis of interleukin-4 production by 10 BALF and 10 PB clones showed large variations between individual CD4+ clones (BALF: range, < 100 to 700 pg/ml; PB: range, < 100 to 1,100 pg/ml), indicating the generation of different types of clones, which was also clear from analysis of interferon-gamma production. The analysis of properties of BALF T-cell clones and their regulation will improve insight into immunologic reactions in the lungs.


Flow cytometric analysis of lymphocyte phenotypes in bronchoalveolar lavage fluid: comparison of a two-color technique with a standard immunoperoxidase assay. Characterization of lymphocytes in bronchoalveolar fluid has provided insight into the pathogenesis of many pulmonary diseases. Identification of lymphocyte phenotypes has become highly successful due to development of specific monoclonal antibodies and reliable methods for detecting labeled cells such as flow cytometry (FCM) and immunocytochemistry. FCM permits rapid screening of many cells, but this analysis may be confounded by heterogeneity in the size and granularity of the cells being evaluated. Such heterogeneity may lead to exclusion of cells of interest and inclusion of unwanted cells. Often peripheral blood leukocytes are used to define the gate for lung lymphocytes, but this gate may be inappropriate due to considerable variation in size and granularity of cells in bronchoalveolar lavage (BAL) fluid. Here we report an alternative method for generating a gate which employed fluorescence and side scatter signals to analyze lymphocyte subsets in BAL fluid by FCM. This gating technique avoids the pitfalls inherent in using the conventional lymphocyte gate to analyze lung cells. To validate this approach, we compared the results generated by this gate and those from the conventional forward/side light scatter gate to results derived from an immunocytochemical technique (ABC) that has been extensively employed in our laboratory to identify lymphocyte subsets in blood and lavage fluid. FCM tended to underestimate the proportions of T-cell subsets compared with ABC when the conventional gate was used. Counting only cells that stained with fluorescein-conjugated anti-CD45 antibody and that had side scatter properties of lymphocytes, however, resulted in excellent agreement between FCM and ABC. It appears that the CD45+/side scatter gate includes the vast majority of lymphocytes in BAL fluid while excluding most of the nonlymphoid cells that contaminate the conventional gate. It was this latter group of cells, and erythrocytes in particular, that led to the artificially low values for lymphocyte phenotypes in BAL fluid by FCM when the conventional lymphocyte gate was used. Although erythrocytes in BAL fluid may be eliminated by hypotonic lysis, this may also result in contamination of the conventional lymphocyte gate with nuclear debris and particulates from macrophages. Despite these advantages, the fluorescence/side scatter gate may not always be optimal for the evaluation of T lymphocytes if BAL fluid contains CD45+, nonlymphoid cells with low side light scatter. In these instances, additional antibodies such as anti-CD14 and anti-CD11 may be employed to determine the size of contaminant monocytic cells and neutrophils.(ABSTRACT TRUNCATED AT 400 WORDS)


Increased fibronectin mRNA in alveolar macrophages following in vivo hyperoxia. Oxygen-mediated lung injury can stimulate a fibroproliferative response resulting in the alteration of the pulmonary extracellular matrix and subsequent scarring of parenchymal tissue. Fibronectin (FN), a component of the extracellular matrix, appears in increased quantities in fibrotic lung disease. Alveolar macrophages (AMs) are a potential source of this molecule. Using quantitative in situ hybridization, we demonstrated that AMs from rabbits acutely exposed to 100% oxygen (hyperoxia) for up to 64 h have 20-fold greater levels of FN mRNA relative to cells from control animals. When animals were allowed to recover in room air for up to 72 h after maximal oxygen exposure, AM FN mRNA abundance approached baseline levels. Furthermore, in oxygen-exposed animals, the fraction of lavaged cells expressing FN mRNA was increased 10-fold relative to controls. Although there was marked cell-to-cell variation, we conclude that the AM is a potential source of FN in the events leading to hyperoxia-induced pulmonary fibrosis.


The application of contrast agents in the evaluation of neoplasms of the central nervous system. Magnetic resonance evaluation of central nervous system neoplasms has improved tremendously since the introduction of gadolinium-based contrast agents. The optimal application of these agents in clinical imaging, however, has not been well established. The article discusses the recent application of these agents to a number of intracranial neoplasms, including metastases, gliomas, pituitary adenomas, and acoustic neurinomas/cerebellopontine angle tumors.


Magnetic resonance imaging of adult intra-axial brain tumors. The detection and characterization of intra-axial tumors in the adult have been greatly improved with the advent of magnetic resonance (MR) imaging, particularly when combined with paramagnetic contrast enhancement. MR imaging allows tumor localization along with evaluation of edema, tumor margins, intrinsic signal intensity on T1- and T2-weighted sequences, and the presence or absence of enhancement. Consideration of these characteristics together with pertinent clinical history forms the basis of a reasonable differential diagnosis. The article summarizes the MR imaging characteristics and pathologic findings of the major intra-axial tumors of adults with emphasis on differential considerations.


Adult extra-axial brain tumors.

Adult extra-axial brain tumors. Magnetic resonance imaging is the preferred cross-sectional imaging study for the evaluation of nearly all extra-axial brain tumors in adults. This article outlines the neoplasms by their pathology. The discussion covers the neoplasms originating from central neuroglial cells, meninges, and cranial nerves. In addition, developmental tumors and cysts and secondary extra-axial tumors are discussed.


Pediatric primary brain tumors.

Pediatric primary brain tumors. Magnetic resonance (MR) studies of pediatric brain tumors have been reported. Instead of reviewing previous studies, this article addresses specific subjects related to pediatric brain tumors, including MR signal characteristics, fourth ventricular tumors, pineal region tumors, tumors in chronic epilepsy, tumors in early infancy, and brain tumors in phakomatoses.


Uses and limitations of spoiled gradient-refocused imaging in the evaluation of suspected intracranial tumors. This article describes the use of a radiofrequency-spoiled gradient-recalled (SPGR) imaging pulse sequence in the evaluation of intracranial masses. This pulse sequence provides excellent anatomic detail with T1-weighted image contrast. Rapid, sequential, single-slice (two-dimensional) images of the brain can be obtained in patients who are unable to hold still for long periods of time. In addition, volumetric (three-dimensional) image data sets can be obtained that provide extremely thin (1- to 2-mm) sections of high detail and good signal-to-noise ratio for selected critical structures within the brain. Finally, because SPGR is also utilized for time-of-flight angiography, parenchymal information can be obtained simultaneously with cerebral blood vessel definition. One potential pitfall that the magnetic resonance radiologist must be aware of is the fact that, in many patients, the degree of contrast enhancement is greatly diminished on postgadolinium SPGR images compared with conventional spin-echo T1-weighted images. Comparison with a set of standard spin-echo postcontrast images or, potentially, the use of higher doses of gadolinium may solve this problem. In spite of this limitation, the selective utilization of SPGR imaging can yield additional useful information for evaluation and preoperative planning in patients with intracranial masses.


Sellar and juxtasellar neoplasms.

Sellar and juxtasellar neoplasms. Magnetic resonance imaging is the modality of choice for evaluating lesions in and around the sella turcica. The article highlights various neoplasms of the pituitary gland and the juxtasellar region. The differentiating imaging characteristics and clinical presentations of these neoplasms are discussed. Even with the best imaging techniques available, however, biopsy or excision of the lesion is still necessary to establish the histologic diagnosis.


Protein targeting to and translocation across the membrane of the endoplasmic reticulum. Several approaches are currently being taken to elucidate the mechanisms and the molecular components responsible for protein targeting to and translocation across the membrane of the endoplasmic reticulum. Two experimental systems dominate the field: a biochemical system derived from mammalian exocrine pancreas, and a combined genetic and biochemical system employing the yeast, Saccharomyces cerevisiae. Results obtained in each of these systems have contributed novel, mostly non-overlapping information. Recently, much effort in the field has been dedicated to identifying membrane proteins that comprise the translocon. Membrane proteins involved in translocation have been identified both in the mammalian system, using a combination of crosslinking and reconstitution approaches, and in S. cerevisiae, by selecting for mutants in the translocation pathway. None of the membrane proteins isolated, however, appears to be homologous between the two experimental systems. In the case of the signal recognition particle, the two systems have converged, which has led to a better understanding of how proteins are targeted to the endoplasmic reticulum membrane.


Mechanisms that determine the transmembrane disposition of proteins. The final orientation that a protein assumes in the membrane of the endoplasmic reticulum is determined by a few types of signal sequences and their respective interactions with the membrane insertion complex. Membrane insertion occurs via a series of discrete steps, some of which are regulated by GTP- and ATP-binding proteins. Analysis of the protein components in proximity to nascent secretory and membrane proteins has revealed novel proteins in the endoplasmic reticulum that may form part of the membrane insertion complex.


Genetic and biochemical analysis of vesicular traffic in yeast. Secretory, vacuolar and membrane protein transport in yeast occurs by processes that are highly conserved in eukaryotic cells. Recent years have seen a proliferation of approaches to the study of vesicular traffic, and in certain instances key breakthroughs have been achieved through the application of genetic and biochemical methods that are well suited to yeast as an experimental organism. The availability of the genetic approach has led to molecular insights concerning the mechanisms of vesicle biogenesis, targeting and fusion.


Regulation of intracellular membrane transport. A number of proteins that are necessary for membrane transport have been identified using cell-free assays and yeast genetics. Although our knowledge of transport mechanisms remains limited, common themes are clearly emerging. In particular, specific GTP-binding proteins appear to be involved, not only at all steps of membrane traffic but also at more than one check-point within each step. The ordered sequence of events occurring during vesicle formation, targeting and fusion may be regulated in a stepwise manner by specific GTP-dependent switches, which act as modular elements of the transport mechanism.


The endoplasmic reticulum-Golgi intermediate compartment. The recent identification of an endoplasmic reticulum-Golgi intermediate compartment has added to the complexity of the structural and functional organization of the early secretory pathway. Protein sorting along the endoplasmic reticulum-Golgi pathway depends on different signals and mechanisms, some of which guarantee recycling from various levels of the Golgi apparatus to biosynthetically earlier compartments.


Regulation of vesicular and tubular membrane traffic of the Golgi complex by coat proteins. Transport of cargo through and from the Golgi complex is mediated by vesicular carriers and transient tubular connections. Two classes of vesicle have been implicated in the biosynthetic or anterograde membrane traffic of this organelle. Both classes of vesicle are coated on the cytoplasmic surface with proteins, of which at least one component is related. Tubular connections also enable exchange of material between membrane-bounded compartments associated with the Golgi complex, most obviously in cells that have been treated with the drug, brefeldin A. Coat proteins appear to be involved in the regulation of these transport processes. Their putative functions include sorting of cargo, as well as regulation of budding, fusion or targeting of the membrane carriers.


Biogenesis of storage granules and vesicles. The production of storage granules and vesicles that undergo regulated exocytosis occurs via biosynthetic and endocytotic pathways, respectively. Prominent in the formation of secretory granules in the Golgi apparatus is selective protein aggregation, which may account for the biogenesis of multiple granules in a single cell. New cDNA transfection and immunolocalization studies have helped to further refine our understanding of the relationship between the formation of regulated secretory vesicles and the early stages of the endocytotic pathway. Recent insights into the targeting of membrane proteins to these organelles have implicated both specific sorting signals and protein-protein aggregation.


W(h)ither default? Sorting and polarization in epithelial cells. The discovery of basolateral sorting signals in the past year may leave the default pathway with nowhere to go. With new results suggesting that even more GTP-binding proteins and coatamers might be involved in transport and targeting, it is clear that the age of mapmaking in polarization research is nearly over.


Structure and biological effects of lipid modifications on proteins. Both the prevalence of lipid modifications of proteins and their importance for protein function and cellular localization have been widely observed. The advances made during the past year in defining the enzymology of lipid addition and in understanding the biological consequences of these modifications on protein function are discussed.


Putting energy into mitochondrial protein import. The import of proteins into mitochondria occurs in several steps. At least three of these steps require ATP and involve molecular chaperones. This energy requirement has served as a useful tool for elucidating the import pathways into the four mitochondrial compartments.


Organellar proton-ATPases.

Organellar proton-ATPases. Proton pumps that belong to the families of F-ATPases and V-ATPases operate without the formation of a phosphorylated intermediate and contain several subunits grouped into distinct catalytic and membrane sectors. Recent studies on the structure and molecular biology of V-ATPases shed light not only on the structure-function relations between the two families, but also on their evolution in all organisms.


Determinants of the calcium permeation of ligand-gated cation channels. Fast synaptic transmission in the vertebrate brain is mediated by ligand-gated channel receptors. As some of these receptors have been implicated in learning and memory, it is important to understand their mechanism of action at a molecular level. Excitatory receptors are members of large gene families of related channels that are gated by acetylcholine, serotonin, and the most abundant neurotransmitter, glutamate. Within the last year, a number of important studies have focused on the ability of these channels to flux calcium ions. Calcium entry into neurons through some of these channels triggers biochemical cascades, which can lead to changes in synaptic efficacy, presumed to be a requisite for memory formation, or if it occurs in excess, to cell death. Recent studies that attempt to determine the channel structures responsible for this calcium conductance will be discussed.


Sodium-calcium exchange.

Sodium-calcium exchange. During the past year, significant advances have been made in the investigation of molecular, kinetic and electrophysiological aspects of Na(+)-Ca2+ exchange. The cardiac and retinal exchangers have been cloned and structure-function studies have begun.


Membrane transport proteins: implications of sequence comparisons. Analyses of the sequences and structures of many transport proteins that differ in substrate specificity, direction of transport and mechanism of transport suggest that they form a family of related proteins. Their sequence similarities imply a common mechanism of action. This hypothesis provides an objective basis for examining their mechanisms of action and relationships to other transporters.


Sodium cotransport proteins.

Sodium cotransport proteins. Significant advances have been made in elucidating the structure of Na+ cotransport proteins. Some fifteen of these low-abundance proteins have been cloned, sequenced and functionally expressed. They are members of the 12 membrane-spanning superfamily and they segregate into two groups, the Na+/glucose (SGLT1) and Na+/Cl-/GABA (GAT-1) families. SGLT1 transporters are expressed in bacteria and animal cells, while GAT-1 transporters are mostly expressed in the brain. None have yet been found in plants.


Structure, function and evolutionary relationship of proteins containing a disintegrin domain. Disintegrins are soluble integrin ligands from snake venoms that disrupt cell-matrix interactions. Recently, the nuclear magnetic resonance structures of two disintegrins were determined, providing provocative molecular insight into how a disintegrin may engage an integrin. In addition, it has recently been realized that disintegrins are derived from larger multifunctional proteins, and that there is a family of membrane-anchored, disintegrin domain-containing proteins that may promote important cell-cell interactions.


Inside-out integrin signalling.

Inside-out integrin signalling. Integrins are expressed by virtually all cells and play key roles in a range of cellular processes. Changes in the integrin surface repertoire provide a means of altering the strength and ligand preferences of cell adhesion. Recent research has examined the affinity modulation of integrins, a rapid and versatile mechanism of cell adhesion regulation. Studies with a prototype, alpha IIb beta 3, indicate that intracellular events influence the conformation and ligand-binding affinity of the extracellular domain of integrins. This 'inside-out' signal transduction appears to be mediated through the integrin cytoplasmic domains. In addition, in some cases affinity modulation of integrins may be cell-type specific. The clarification of the mechanisms of integrin affinity modulation should help explain rapid changes in cell adhesion that occur during cell migration, aggregation and the cell cycle.


The role of proteoglycans in cell adhesion, migration and proliferation. Proteoglycans comprise a part of the extracellular matrix that participates in the molecular events that regulate cell adhesion, migration and proliferation. Their structural diversity and tissue distribution suggest a functional versatility not generally encountered for other extracellular matrix components. This versatility is mainly dictated by their molecular interactions and their ability to regulate the activity of key molecules involved in several biological events. This molecular cooperativity either promotes or inhibits cell adhesion, migration and proliferation. A growing number of studies indicate that proteoglycans can play a direct role in these cellular events by functioning either as receptors or as ligands for molecules that are required for these events to occur. Such studies support a role for proteoglycans as important effectors of cellular processes that constitute the basis of development and disease.


Membrane proteases: roles in tissue remodeling and tumour invasion. The coordinated control of extracellular matrix degradation on the cell surface involves three crucial elements: secreted proteases and their inhibitors, surface protease receptors and integral membrane proteases. The roles that each of these elements play in cell surface proteolysis are described. The localization of proteases to the cell surface, protease activation, and regulation of cell surface proteolysis by protease inhibitors are key issues for elucidating the role of membrane proteases in tissue remodeling and tumour invasion.


Assembly of extracellular matrix.

Assembly of extracellular matrix. A great challenge in understanding how different extracellular matrices assemble is to sort through the vast number of possible interactions between and among matrix molecules. The most profound insights are likely to come from patients with defined defects of matrix molecules and the use of transgenic mice or other experimental technologies that mimic the complexity of the human system.


Functional domains of cell adhesion molecules. A number of molecules involved in cell adhesion (e.g. fibronectin, laminin, collagens I and IV, thrombospondin, entactin) have now been identified and the consequent roles that they play in the processes of growth, migration, differentiation and tumor spread have been described. Active sequences of the molecules have been identified using synthetic peptides derived from specific domains. Several adhesive molecules contain multiple active domains with different biological activities.


Adhesion cascades: diversity through combinatorial strategies. Cell adhesion occurs via a highly regulated set of sequential interactions. Prototypic components of a variety of adhesion cascades are discussed, including integrins, triggering molecules and lectin-carbohydrate interactions. Selectivity and efficiency are achieved by utilizing the right combination of multiple adhesion molecules and by their coordinated biochemical regulation.


Endothelial cells: adhesion and tight junctions. This article reviews recent discoveries concerning the identity of endothelial cell adhesion molecules and their participation in intercellular junction formation. Observations relating to the formation of high-resistance tight junctions between brain endothelial cells are emphasized.


Molecular linkage between cadherins and actin filaments in cell-cell adherens junctions. The cell-cell adherens junction is a site for cadherin-mediated cell adhesion where actin filaments are densely associated with the plasma membrane through its well-developed plasmalemmal undercoat. Recent research has focused on the molecular linkage between cadherins and actin filaments in the undercoat of adherens junctions in order to understand the functions of these undercoat-constitutive proteins in the regulation and signal transduction of cadherin-based cell adhesion.


Leukocyte-endothelial cell interactions. The movement of leukocytes from the blood circulation into organized lymphoid tissues or sites of inflammation requires cooperative interactions between signaling and adhesion molecules. Selectins mediate the initial rolling contacts of leukocytes with the endothelium. Following leukocyte activation, integrins strengthen adhesion and then direct migration beneath the endothelium. Unique combinations of signaling and adhesion molecules may regulate the subsets of leukocytes that are recruited into specific tissues.


Regulation of cartilage and bone differentiation by bone morphogenetic proteins. Quantum advances have recently been made in the understanding of the regulation of cartilage and bone differentiation through the identification, purification, genetic cloning and expression of recombinant bone morphogenetic proteins. Bone morphogenetic proteins are a family of pleiotropic differentiation factors with actions on chemotaxis, mitosis, initiation and promotion of chondrogenic and osteogenic phenotypes. They bind extracellular matrix components, heparin and type IV collagen and initiate bone repair. The cascade of cartilage and bone differentiation consists of several continuous phases: initiation, promotion, maintenance and termination.


Synthesis, assembly and function of plant cell wall macromolecules. The plant cell wall consists of a structurally intricate network of polysaccharide and protein whose biosynthesis, assembly and functions are still poorly understood. Recent research has shown how cell wall macromolecules, and fragments thereof, appear to be involved in processes such as cell growth, cell and tissue differentiation and the control of pathogenesis.


Modulators of neuronal migration and neurite growth. A multitude of molecules have been identified over the past few years that promote neurite outgrowth in vitro. The concept that these molecules work mainly by providing an adhesive surface for neuronal growth cones has been challenged by evidence from recent experiments. Some of the substrate molecules have diverse actions on cell migration and neurite growth. In addition, there is now evidence that there are molecules that specifically inhibit growth cone locomotion. This has given rise to the hypothesis that growth cones integrate a variety of growth-promoting and inhibitory signals and translate them into directed locomotion.


Fibroblast growth factor-stimulated phosphorylation of a lipocortin I-like protein is S-phase cell cycle specific in human vascular endothelial cells. We examined whether the phosphorylation of a 34 kDa lipocortin I-like protein may be associated with internalization process of fibroblast growth factor (FGF) in human umbilical vein endothelial (HUVE) cells. We show that: 1) exposure of synchronized HUVE cells to basic FGF for an appreciable time lag (> or = 30 min) at 37 degrees C and subsequent phosphorylation at 37 degrees C are required to obtain an increased 32P-labelling of a 34 kDa substrate; 2) this FGF-stimulated phosphorylation occurs in S phase but not G1 phase of the growth cycle; 3) the 34 kDa substrate appears to be phosphorylated on tyrosine residues; 4) a major fraction of the 34 kDa 32P-labelled substrate is immunoprecipitated with an antibody that has been raised against human lipocortin/annexin of type I. It is suggested that internalized FGF-receptor/kinase complexes might be primarily responsible for the phosphorylation of the 34 kDa lipocortin I-related protein in S phase HUVE cells.


Intermolecular cystine-bonding of murine interleukin 2 indicates that ligand dimerization is important for the formation of the high-affinity receptor complex. Interleukin 2 is thought to be active as a monomeric protein. As the nonessential Cys-140 of murine interleukin 2 (mIL2) is located in the hydrophobic interface of the amphiphilic F domain it was successfully used to stabilize hydrophobic amino acid contacts between two mIL2 cores yielding biologically active cystine-bonded dimeric mIL2. (3H) thymidine incorporation assays with intermolecular cystine-bonded or monomeric mIL2 revealed almost identical median effective concentrations (EC50) and high-affinity dissociation constants (Kdh), respectively. Comparative binding and internalization assays suggest that one cystine-bonded dimeric or two monomeric mIL2 molecules bind to the high-affinity receptor complex. Furthermore, DSS concentration-dependent crosslinking studies using monomeric mIL2 revealed four membrane-derived protein-complexes with apparent molecular weights of about 70 kDa, 85 kDa, 95 kDa and 100 kDa, respectively, showing that both mIL2 receptor chains may be crosslinked to a monomeric or dimeric ligand molecule, respectively. We therefore propose that dimerization of murine interleukin 2 occurring either in solution at concentrations above the low-affinity dissociation constant or at the low-affinity receptor is important for regulation of high-affinity complex formation and signal transduction.


High levels of biologically active vascular endothelial growth factor (VEGF) are produced by the baculovirus expression system. Vascular endothelial growth factor (VEGF) is a recently discovered mitogen for endothelial cells in vitro, and a potent angiogenesis promoting factor in vivo. VEGF is secreted from producing cells as a homodimer, binds to specific receptors on the cell surface of endothelial cells, and is produced in four forms as a result of alternative splicing. We have expressed the cDNA encoding the 165 amino-acid long isoform of VEGF in insect cells using the baculovirus based expression vector. We show that infected insect cells secrete large amounts of VEGF. Antibodies directed against a synthetic peptide prepared from human VEGF identify the secreted factor. The baculovirus derived VEGF expressed in insect cells (inVEGF) binds directly to the VEGF receptors inVEGF competes with pure mammalian cells derived [125I]-VEGF for binding to the VEGF receptors that are present on the cell surface of endothelial cells. Furthermore, inVEGF is biologically active and induces the proliferation of human umbilical vein derived endothelial cells.


Expression and characterization of bone morphogenetic protein-2 in Chinese hamster ovary cells. Bone is a dynamic tissue that responds to many factors including vitamin D, parathyroid hormone, estrogen, calcitonin, and bone morphogenetic proteins (BMPs). The ability to stimulate new bone growth would permit novel therapies for situations where bone mass has been lost due to accident or disease. Purified BMP-2, in conjunction with a suitable matrix, is sufficient to stimulate the synthesis of new bone (Wang et al., 1990). We have expressed recombinant human BMP-2 at high levels in Chinese hamster ovary cells using methotrexate-mediated gene amplification. Several forms of BMP-2 are secreted from CHO cells: (1) an amino-terminal propeptide of 40-45 kDa, (23) a mature active 30 kDa homodimer consisting of 18-22 kDa subunits, and (3) a small amount of uncleaved 60 kDa precursor protein. The mature, active protein is predominantly a 30 kDa homodimer consisting of subspecies of 18 and 22 kDa which differ by proteolytic processing at their amino termini. Mature BMP-2 and propeptide contain high mannose and complex N-linked oligosaccharides, respectively. The molar amount of secreted, processed propeptide is approximately 5-fold higher than mature BMP-2 in conditioned medium. BMP-2 associates with both the extracellular matrix and the surface of CHO cells, which may in part account for the unequal levels of extracellular propeptide and mature forms of the molecule in the conditioned medium. Recombinant BMP-2 can be expressed in sufficient quantities to assess its therapeutic potential for bone regeneration.


Purification and biochemical characterisation of human and murine stem cell inhibitors (SCI). We have recently characterised an inhibitor of haemopoietic stem cell proliferation (SCI/MIP-1 alpha) and report here on its purification and initial biological and biochemical characterisation. The activity can be detected by direct addition to the CFU-A stem cell assay and this simple test for inhibitory activity has greatly facilitated the purification of the molecule. The purification involves a combination of Mono Q ion exchange chromatography, heparin-sepharose affinity chromatography and Blue Sepharose affinity chromatography. The purified stem cell inhibitor is an 8 kD peptide which is identical to the previously described peptide macrophage inflammatory protein 1 alpha. The peptide has a natural tendency to form large self-aggregates and appears, in physiological buffers, to have a native molecular weight of around 90 kD. SCI is a heat stable, protease sensitive protein which is half maximally active at between 10 and 25 pM in the CFU-A assay. The self-aggregates can be disrupted by dilute solutions of acetic acid and it appears that disruption increases the specific activity of SCI preparations. We also report the characterisation of the human homologue of the stem cell inhibitor (human SCI/MIP-1 alpha) which is 74% identical to murine MIP-1 alpha and which shares all the above features of the murine inhibitor.


Binding of a novel radioiodinated thromboxane A2/prostaglandin H2 antagonist to guinea pig lung membranes. The utilization of a novel radioiodinated TXA2/PGH2 receptor antagonist, ISAP (7-[(1R,2S,3S,5R)-6,6-dimethyl-3(4- iodobenzenesulfonylamino)-bicyclo[3.1.1]-hept-2-yl]-5(Z)-heptenoic acid) to characterize TXA2/PGH2 receptors from guinea pig lung parenchymal membranes in radioligand binding assays is described. [125I]ISAP binding was saturable, displaceable, and dependent upon protein concentration. The time course of binding yielded k1 = 2.12 x 10(8) M-1 min-1, k1 = 4.46 x 10(-3) min-1, Kd = k-1/k1 = 17.8 pM. Equilibrium binding studies indicated a single class of high affinity binding sites with a Kd of 52.7 +/- 1.9 pM and a Bmax of 92.7 +/- 7.2 fmoles/mg protein (n = 4). Binding was inhibited by a series of structurally diverse mimetics and antagonists with the rank order of potency IBOP greater than ONO11113 = SQ26655 greater than U46619 (mimetics) and (d)-S-145 greater than ISAP greater than (1)-S-145 greater than SQ29548 greater than BM13505 = I-PTA-OH (antagonists), with entantioselectivity of binding demonstrated by (d) and (1) S-145. Binding was also inhibited by prostanoids (PGD2, PGF2 alpha, and 9 alpha, 11 beta-PGF2) thought to act at the airway TXA2/PHH2 receptor, but not by histamine or carbachol, and only weakly by LTB4 and LTD4, consistent with specific binding to the lung TXA2/PGH2 receptor.


Aspirin abolishes the decreased low-density lipoprotein (LDL) entry into the rabbit arterial wall induced by the calcium channel blocker isradipine. After deendothelialization and experimentally induced hypercholesterolemia in rabbits, an increased LDL entry into the vascular wall can be monitored using radiolabelled LDL. In male rabbits aged 6 months the abdominal aortic endothelium was removed by a Fogarty catheter. The animals fed a 1% cholesterol supplemented diet were treated either with isradipine (0.3 mg/kg/daily) (n = 36) alone or in combination with aspirin (5 mg/kg/daily) (n = 36) for four weeks. Thirty-six animals served as controls. 1, 3, 6, 12, 24 and 48 hours prior to sacrificing, 10 microCi 125I-LDL was administered intravenously to six rabbits in each group. The LDL entry was quantified in the abdominal aorta according to morphologically assessed type of surface lining. Aortic cholesterol content was assessed by Sudan-III staining and quantitative determination. Endothelialized segments exhibited a significantly (p less than 0.05 - p less than 0.001) lower LDL uptake as compared to re- or deendothelialized segments. The LDL entry was significantly lower with isradipine treatment than in controls. In parallel the cholesterol content decreased and the Sudan-III-positive areas were smaller in size. This beneficial effect as well as that on aortic lipid content was abolished by a pretreatment with aspirin. While in the isradipine-treated animals PGI2 synthesis was significantly (p less than 0.01) enhanced, it was almost completely blocked by aspirin. These findings indicate that the benefit of reduced LDL entry caused by isradipine may be mediated by an increased endogenous PGI2 synthesis.


Structure elucidation of oxygenated lipids in human atherosclerotic lesions. Oxidative modification of low density lipoproteins and tissue lipids has been proposed to be involved in the pathogenesis of atherosclerosis. We examined human atherosclerotic lesions of various stages from fifteen victims of acute heart failure and detected substantial amounts of oxygenated fatty acids in the tissue ester lipids. The degree of lipid oxygenation correlated with the stage of advancement of the lesion. More than 85% of the oxygenated fatty acids were localized in the cholesterol esters, whereas phospholipids contained only small amounts. Structure elucidation of the oxygenation products indicated a nonspecific product pattern of various isomers of keto- and hydroxy-octadecadienoic acid. The data presented suggest an involvement of lipid peroxidation in the pathogenesis of atherosclerosis and indicate that the majority of the oxygenation products are formed via nonspecific, non-enzymatic reactions possibly initiated by the action of a 15-lipoxygenase.


Effect of prostaglandin E2 or prostaglandin synthesis inhibitors on human gonadotrophins and prolactin. A role for prostaglandins (PGs) in the release of pituitary hormones in humans is controversial. The effect of PGE2 or PG synthesis inhibitors on gonadotrophin and prolactin (PRL) levels was evaluated in 50 volunteers (25 males and 25 females). Forty cases in four equal groups (Group I & II were males and group III & IV were females) received iv infusion of PGE2 in one cycle and non-steroidal anti-inflammatory drugs (NSAID) [Indomethacin or Naproxen] in the subsequent cycle. Control groups A & B (5 males and 5 females) received saline infusions in one cycle and placebo capsules in the next cycle. Neither PGE2 nor any of the two NSAID altered the basal levels of FSH or LH significantly. PGE2 infusions in males depressed PRL levels significantly two hours after the onset of infusions. Indomethacin raised PRL levels while Naproxen did not. In women, a similar response was also observed but prolactin levels decreased earlier (30 min from the PGE2 infusion). These data indicate a probable role for PGE2 or other prostanoids as well in the regulation of human PRL release but not in gonadotrophin secretion.


Effect of 25-hydroxycholesterol on cytotoxicity and prostacyclin production in cultured human umbilical arterial endothelial cells. The effect of cholesterol or 25-hydroxycholesterol on DNA synthesis and prostacyclin synthesis by cultured human umbilical arterial endothelial cells was investigated. Cells incubated with 25-hydroxycholesterol showed an increased rate of cell death, decreased [3H]-thymidine incorporation and increased prostacyclin production as compared to either the control or the pure cholesterol group. 25-hydroxycholesterol caused a concentration- and time-dependent increase in prostacyclin synthesis. The intracellular free calcium concentration of endothelial cells incubated with 25-hydroxycholesterol was markedly increased in a time-dependent manner. Calcium uptake by endothelial cells incubated with 25-hydroxycholesterol for 24 h was markedly increased. It is suggested that 25-hydroxycholesterol may depress DNA synthesis and increase prostacyclin synthesis via an elevation in the intracellular free calcium concentration of endothelial cells.


Thromboxane synthase inhibition in allergen challenged sheep lung: effect on eicosanoid synthesis. We determined the effect of a novel inhibitor of thromboxane synthase, DP1904, on the baseline and allergen stimulated release of eicosanoids into the bronchoalveolar lavage fluid of sheep. DP1904 was effective in reducing the baseline and allergen stimulated production of TXB2. Inhibition of thromboxane synthase was associated with an increase in other prostaglandin endoperoxide metabolites, PGE2 and PGD2. Diversion of endoperoxide metabolism occurs in sheep lung tissue in vivo.


Leukotriene formation by mouse connective tissue mast cells. Stimulation of peritoneal cells from BALB/c, CBA/J or WBB6F1(-)+/+ mice with IgE/antigen caused the release of mast cell granules and leukotriene C4. No leukotriene formation was observed with peritoneal cells from mast cell-deficient WBB6F1-W/Wv mice. Mast cells (greater than 98% purity), separated on metrizamide gradients, did not synthesize detectable amounts of leukotriene C4 when challenged immediately after purification. Co-culture of the mast cells with 3T3 fibroblasts restored the capability of the mast cells to produce leukotrienes. Addition of IL-3 during culture enhanced the synthesis of this eicosanoid. The 5-lipoxygenase inhibitor A-63162 blocked the leukotriene formation. Western blot analysis confirmed the presence of 5-lipoxygenase in connective tissue mast cells. These experiments demonstrate that mouse peritoneal (connective tissue) mast cells can produce significant amounts of leukotrienes.


A Calluna vulgaris extract 5-lipoxygenase inhibitor shows potent antiproliferative effects on human leukemia HL-60 cells. A water-Calluna vulgaris extract (water-CVE) was found to be a relatively specific arachidonate 5-lipoxygenase inhibitor and showed potent anti-proliferative effects on human leukemic HL60 cells. Water-CVE completely inhibited potato 5-lipoxygenase activity at 250 micrograms/ml, partially inhibited soybean 15-lipoxygenase at pH 7.4 and had no effect either on this 15-lipoxygenase at its optimal activity pH (pH 9) or on Lupinus albus 5-, 8-, 15-lipoxygenase. In culture, the proliferation and DNA synthesis of HL60 cells were decreased by water-CVE in a dose-dependent manner with an IC50 of 200 micrograms/ml at day 4. This effect of water-CVE is related to the starting density of HL60 cells. These results suggest that arachidonate 5-lipoxygenase metabolites and/or leukotrienes could play an essential role in cellular functions of leukemic cells and may explain the success of the use of Calluna vulgaris as tea and baths in folk medicine.


Influence of HDL on the formation of 6-keto-PGF1 alpha and TXB2 in vitro: the importance of the source of HDL. The influence of HDL, isolated from normolipidemic human blood and blood of normo- and hyperlipidemic rabbits, on in vitro 6-keto-PGF1 alpha synthesis by rabbit aorta and on TXB2 synthesis by platelets of clotting human and rabbit blood was tested. The HDL fraction from normolipidemic subjects, when incubated with blood from normolipidemic humans or rabbits, inhibited TXB2 formation. The same fraction stimulated the formation of 6-keto-PGF1 alpha after incubation with rabbit aorta taken from normolipidemic animals. HDL taken from hyperlipidemic rabbits inhibited 6-keto-PGF1 alpha formation in rabbits and had no influence on TXB2 formation. These results support the hypothesis that not only is the absolute amount of HDL important for its influence on prostanoid formation, but also the origin and the composition of the HDL fraction.


Elevated maternal plasma immunoreactive phospholipase A2 in human preterm and term labour. Peripheral plasma concentrations of immunoreactive phospholipase A2 (irPLA2) (Type II, non-pancreatic) were determined in 110 women during pregnancy. The concentration of irPLA2 did not significantly change during pregnancy (5.7 +/- 0.6 ng/ml, n = 72) until the onset of labour. When compared with non-labouring women, irPLA2 concentrations were significantly elevated in association with both preterm labour (13.3 +/- 2.4 ng/ml, n = 15, p less than 0.02) and labour at term (10.4 +/- 1.7, n = 23, p less than 0.02). These data suggest that maternal plasma irPLA2 may be reflective of the mechanism(s) underlying the labour-associated increase in human gestational tissue eicosanoid formation.


[Cognitive functions in multiple sclerosis]. Although the presence of intellectual impairment in multiple sclerosis (MS) is known since the first studies of the disease frequently the impairment goes equally undetected for the patients, their family and the physician because the physical dysfunction is much more outstanding. In this study a population of 50 persons suffering clinically definite MS (Poser's criteria) and 50 healthy controls matched with the patients in sex, age and cultural level were submitted to a neuropsychological test battery (NPTB). The existence of a correlation between the punctuation obtained in the NPTB and factors such as the level of disability, the time of evolution, the type of MS and the work status was searched. The results show a greater difficulty in doing tasks requiring attention-concentration skills thus giving the MS patients significantly lower scores in the memory test when compared with the controls. The execution of all tests was worse in those forms of MS with the longest time of evolution, higher EDSS scores and the chronic-progressive types. In our study the loss of the working status was never due to the intellectual impairment, it was because of the physical disability.


[Depression in Parkinson's disease and its relation to the cognitive and motor manifestations]. Evaluation with the geriatric depression scale carried out in 30 patients with Parkinson's disease who did not present subjective complaint of loss of memory or impairment in superior mental function capable of interfering in daily routine showed a high frequency of depression of 50-70% depending on where the cut-off in the geriatric depression scale was located. Depression in these patients does not significantly relate with either cognitive impairment or the degree of motor incapacity. Neither were depression or anxiety in these patients related with demographic data such as the age of the patient, age at onset of the disease, sex, months of evolution, or education. In contrast, a positive correlation was found between depression and anxiety.


[Cognitive functions in multiple sclerosis. Bibliographic review (1980-1991)]. The presence of intellectual impairment in MS has been known since the first studies of Charcot and Vulpain who described the memory's weakening appearing in these patients. However, the interest for the MS' cognitive deficits has specially increased in the decade of the 80's. In this article, a bibliographical revision of the last published studies about the cognitive impairment in MS has been made paying attention to those superior functions known as more affected. The aim of this article is to known the correlation among the cognitive impairment and the MR images, level of disability, fatigue, duration and course of the disease and demographic factors.


[Hemiparesis-ataxia in meningovascular syphilis]. Two cases of lacunar infarction of "ataxic-hemiparesis" type secondary to luetic vasculitis are presented. The first patient presented meningovasculitis and the second progressive general paralysis. In both cases the ischemic lesion was seen by magnetic resonance and was located at a pontine level in one case and in the corona radiata in the other. Treponemal serology in plasma and CSF was positive in both cases with lymphocytic pleocytosis and high CSF protein levels being observed. Clinical and response to treatment was satisfactory except in the case of general paralysis in whom the impairments existing prior to the cerebral infarction persisted. This study complements recent communications in which neurosyphilis was attributed to the appearance of other lacunar type infarctions (pure motor hemiparesis).


The 1991 Elis Berven Lecture. Radiotherapy in the nineties. Increase in cure, decrease in morbidity. Advance in radiotherapy can be achieved by obtaining a greater tumour control and by reducing the morbidity of treatment, both early and late. The factors influencing both means of benefiting the cancer patient are considered.


[Behçet's syndrome with neurological involvement: value of magnetic resonance]. Behçet's syndrome is a rare inflammatory, multisystemic disease of unknown etiology and chronic relapsing course, manifested chiefly by ocular and mucocutaneous lesions. Among its neurologic complications, a cerebral vasculitis can occasionally been observed, upon which there is little information at present. A 31-year-old man presented with fever, weight loss, oral and genital ulcers, blurred vision and memory loss during the last two months. The cerebrospinal fluid contained 170 lymphocytes/microliters. Computed Tomography and cerebral angiography were normal. Magnetic resonance imaging (MRI) showed small hyperintense lesions in the corticomedullary and periventricular regions. The patient's condition improved with corticosteroids. We stress upon the importance of MRI to detect small-vessel vasculitis in Behçet's disease.


[Ischemic cerebrovascular syndrome of pregnancy and the puerperium]. There is little information on ischemic cerebrovascular pathology of pregnancy and puerperium. The clinical characteristics and the results of tomographic and angiographic evaluation of nine patients with ischemic cerebrovascular syndrome of pregnancy and puerperium are described. Venous thrombosis was the cause of cerebrovascular episode in 4 of the 9 patients presenting characteristic clinical manifestations and occurring particularly during puerperium. The diagnostic method of these cases was angiography since the scanner was normal in almost all the cases. Arterial pathology presented preferentially during pregnancy with no peculiar clinical characteristics being observed. In these cases the cerebral scanner was the best diagnostic technique. Follow-up suggested a better prognosis for venous pathology in terms of sequelae.


Diagnosis and treatment of anal carcinoma. An overview. Squamous cell carcinoma of the anal canal gives early symptoms and is easy to diagnose. However, these patients often present with advanced tumours, probably because of patient's and/or doctor's delay. The diagnosis must be confirmed by a conclusive biopsy as the treatment of ano-rectal tumours is based upon correct histopathological diagnosis. Loco-regional tumour control of squamous cell carcinoma is excellent following radiotherapy or combined chemoradiotherapy as only 10-20% of the patients develop a local recurrence. The great majority of these are cured by abdominoperineal resection. However, this treatment involves considerable acute and chronic toxicity, but mortality is less than 2%. There is no general agreement about how to minimize toxicity without hazarding loco-regional tumour control. One way could be to irradiate only the primary tumour site in patients with early lesions, and reserve radiotherapy of regional lymph nodes for more advanced cases. About 20% of the patients develop distant metastases, which make the disease incurable. Hence, frequent, rectal digital examination is the most important follow-up since early local recurrences can easily be cured. There is no general consensus concerning adjuvant chemotherapy, but its potential should be further explored.


Clinical aspects of tumour involvement of the pulmonary vessels. The involvement of the pulmonary vessels by tumour emboli may lead to a clinical picture defined as 'subacute cor pulmonale'. Information about this syndrome has been limited to case reports and a few series. A study of 214 autopsied cancer patients was undertaken to investigate the clinical signs and symptoms of tumour involvement of the pulmonary vessels (TIPV). The lungs were removed as a block and 15 sections (3 from each lobe) were analyzed. Clinical data about right ventricular failure, dyspnoea, cough, pleuritic chest pain, cyanosis, engorgement of jugular veins, peripheral oedema, haemoptysis and haemoptoic sputum were obtained from the medical records of each patient. Tumour emboli were detected in 89 cases, and no respiratory symptoms were recorded in 39. The presence of dyspnoea and cyanosis were highly significant in the group with TIVP, and right ventricular failure and peripheral oedema showed slight significant differences between the patients with and without TIPV. The classical picture of subacute cor pulmonale was observed in 13 patients and TIPV was considered to be the main cause of death in 29 cases. Our results indicate that although the development of subacute cor pulmonale was rare in patients with cancer, TIPV may be suspected when the patient presents respiratory distress and should be included in the differential diagnosis of dyspnoea in cancer patients.


Primary gastric non-Hodgkin's lymphoma. A retrospective clinico-pathological study. Prognostic factors and treatment results were analysed in 72 consecutive patients with primary gastric lymphoma treated between 1970 and 1985. There were 37 patients in stage IE, 17 in IIE, 3 in IIES and 15 in stage IV. Histopathological re-evaluation and classification according to the TNM system were performed. We found that disseminated disease (stage IV), serosal penetration (T3), involvement of adjacent organs (T4) and extensive abdominal lymph node involvement (N3) were poor prognostic factors. Neither histological malignancy grading, nor the appearance of lympho-epithelial lesions were significantly associated with relapse-free survival. Forty-six patients with 'limited localized' disease (stage IE, IIE, N3 excluded) received potentially curative treatment (surgery, radiotherapy, chemotherapy or combinations thereof), of whom 85% remained relapse-free. Thirty-four patients did only get local treatment (surgery and/or radiotherapy) with curative potential, the relapse-free survival rate was 85%. We conclude that primary gastric lymphoma stage IE and IIE (N3 excluded) is often a truly localized disease that can be cured with local therapy.


Age as a determinant of axillary node involvement in invasive breast cancer. We analyzed the age at diagnosis and the tumor size as determinants of axillary node involvement in 725 consecutive patients with breast cancer. The prevalence of nodal involvement increased consistently with tumor diameter from 18.9% in tumors smaller than 10 mm to 72.9% in those measuring 40 mm, or more. The risk also varied with age, the lowest prevalence being found in the youngest and the oldest patients and the highest one in the 40-59-year age group. When analyzed as a continuous variable age was best fitted as a second order term and it was a statistically significant (p = 0.04) determinant of axillary metastases in a multivariate model where tumor diameter, histopathological classification and estrogen receptor concentration were taken into account as possible confounding variables. The findings indicate that the parallelism between the establishment of metastases in lymph nodes and at distant sites may vary with age. The prognostic value of nodal status may therefore depend on age at diagnosis.


Measurement of short-term 11C-thymidine activity in human head and neck tumours using positron emission tomography (PET). Tumour uptake of 11C-thymidine labeled in the methyl position was assessed after intravenous injection in 13 patients with head and neck tumours. This activity was compared to other tracers such as C15O, 13NH3 and C15O2. In every single case a 'positive' tumour image after injection of 11C-thymidine was obtained. Time-activity curves showed the initial activity to be followed by a rapid decrease over the first 10-15 min with an apparent plateau thereafter. A similar level of uptake was found in normal salivary gland regions and myocardium, while higher activities were noted in liver and kidney parenchyma. It is suggested that both blood flow and cellular metabolism can influence 11C-thymidine imaging in this class of human tumours.


Primary malignant lymphoma of the brain. A report of 24 cases from the Norwegian Radium Hospital. Between 1975 and 1987, 24 patients with primary central nervous system lymphoma were seen and treated at the Norwegian Radium Hospital. The overall median survival was 24 months. Patients with poor performance status (WHO 3-4) had a median survival of 3 months whereas patients with good performance status (WHO 0-2) had a median survival of 40 months (p < 0.0001). Patients who were not steroid-dependent after operation had a better survival than those patients who were steroid-dependent (p = 0.02). Nine patients were still living without evidence of disease at last follow-up, 18-130 months after the initial treatment.


Primary non-AIDS related brain lymphoma. Patterns of failure following radiotherapy. Thirteen patients with primary brain lymphoma (PBL) were treated with radiotherapy. Three patients also had ocular involvement with retinal masses at initial presentation. All but one patient received conventional whole brain irradiation and, in addition, spinal irradiation, intrathecal methotrexate or orbital irradiation were given in two, two and four patients respectively. The radiation doses for involved sites ranged from 40 to 65 Gy, and for prophylactic sites from 30 to 50 Gy. After radiotherapy, all patients had complete regression of the tumor on computed tomography. Nine patients relapsed, 5 of them with brain recurrence. Two patients had ocular recurrence exclusively as their first relapse. The remaining two relapsing patients had bone lesions. One patient died intercurrently. As a result, only three patients are alive and free of disease after 16 to 36 months and all three received some adjuvant treatment in addition to whole brain irradiation.


Prognostic factors in radiation-treated esophageal carcinoma. Prognostic factors in esophageal carcinoma treated with irradiation were examined. The prognosis of 111 patients without metastasis who had received more than 60 Gy was analyzed. Significant associations were found between survival rates and tumor length, stage, radioresponse of the primary tumor and the s.c. X-P classification based on barium contrast radiography; superficial type (tumor limited to the surface of the esophageal wall), tumorous type (solid mass without ulceration), Ul-A type (tumor with shallow ulceration with regular margin), Ul-B type (tumor with deep ulceration or irregular ulcer margin), and funneled type (tumor invading the esophageal wall in a scirrhous pattern). In multiple regression analysis, the X-P classification had the strongest correlation with survival and the survival rates of patients with the superficial type, the tumorous type and the s.c. Ul-A type were significantly higher than those of patients with the other tumor types (p < 0.001).


The effect of postoperative radiotherapy on leukocyte zinc, serum trace elements and nutritional status of breast cancer patients. Mononuclear (MNC) and polymorphonuclear cell (PMNC) zinc content was determined together with serum zinc, copper, selenium and iron concentrations in 24 operable breast cancer patients during and after postoperative radiotherapy. Anthropometric and biochemical indices of nutritional status were measured as background data. The measurements were carried out in the years 1987-1988. Nine patients used unconventional multivitamin or trace element preparations. A steady but statistically insignificant decrease in PMNC zinc was seen during treatment. No changes occurred in MNC zinc. Serum copper levels increased in five patients possibly due to tamoxifen treatment, but no other alterations occurred in serum trace element levels. Appetite was well maintained and nutritional status remained unaltered. Postoperative radiotherapy for breast carcinoma had thus no effect on either trace element or nutritional status. Patient-initiated alternative treatments did not significantly affect their trace element levels. This was probably due to small supplementation doses or irregular use of the preparations.


Ondansetron and tropisetron with dexamethasone in the prophylaxis of acute vomiting induced by non-cisplatin-containing chemotherapy. Forty-seven patients receiving non-cisplatin-containing chemotherapy were entered in a prospective study in which the efficacy of ondansetron plus dexamethasone and tropisetron plus dexamethasone in the prophylaxis of acute vomiting was evaluated. Thirty-nine patients were evaluable for cross-over analysis. During the 24 hours following the start of chemotherapy, 97% of patients on ondansetron plus dexamethasone reported total control of vomiting compared with 82% of those on tropisetron plus dexamethasone (p = 0.026). Thus, both 5-HT3- receptor antagonists combined with dexamethasone were highly effective in controlling acute vomiting induced by non-cisplatin-containing chemotherapy. The observed difference between the treatments may be caused by different dose schedules of ondansetron and tropisetron. A double-blind design with equal number of placebo-controlled administrations is needed to ascertain whether there is a significant pharmacological difference between ondansetron and tropisetron.


Modification of radioresponse of sublethally irradiated mouse jejunum by misonidazole. The radiation-induced changes in a critically radiosensitive tissue, jejunum of BALB/c mice and their modification by a hypoxic cell sensitizer, misonidazole (MISO), were studied. Adult mice were exposed to 1.5, 3.0 and 5.0 Gy of 60Co gamma radiation 30 min after MISO injection and quantitative studies in jejunal cross sections were carried out at different post-treatment times from 3 h to 28 d. Radiation-induced damage to the jejunal mucosa was dose-dependent and reached a maximum on day 1 post-treatment in all the groups. MISO pretreated animals did not exhibit any change in the crypt survival or crypt and villous cellularity compared to the radiation alone group. However, there was a significant suppression of mitotic activity by MISO at early intervals after irradiation. This reduction in mitosis in the drug pretreated animals appeared to affect the rate of recovery from radiation damage, which was slower and prolonged compared with that in the radiation alone group.


Binding of cytotoxin P4 from Naja nigricollis nigricollis to B16F10 melanoma and WEHI-3B leukemia cells. Cobra venoms cause irreversible destruction of cells cultured in vitro [1,2]. The venom of Naja nigricollis nigricollis possessed the most potent cytotoxic activity towards B16F10 melanoma cells among various examined venoms [2]. The main cytotoxic factor (P4) isolated from this venom showed preferential activity on tumor cell lines and caused lysis at concentrations of 10(-7) M (0.8-1 micrograms/ml) [3]. The present study examined the binding of cytotoxin P4 to melanoma B16F10 and WEHI-3B leukemia cell lines and found that, like cytotoxicity, it depended on concentration, temperature and incubation time. Cytotoxin concentrations that elicited no apparent damage to cells during the first hour of incubation caused lysis after a longer period of incubation, suggesting that a critical number of bound molecules is required in order to cause cell death. Bivalent ions, such as Mg2+, Ca2+ or Sr2+, which decreased binding to the cells also inhibited cytotoxicity. Competition experiments as well as the displacement of 75% of the bound radiolabelled cytotoxin with 'cold' cytotoxin, suggest the presence of specific binding sites for the toxin in the examined tumor cells. The non-specific binding of the cytotoxin P4 to sea urchin ova and sperm cells without affecting their fertility, even at high concentrations of 10(-5) M, indicates that the specific binding to cells is probably a necessary condition for cell lysis.


The effect of the presence of integral membrane protein (human band 3) on the membrane lytic properties of melittin in reconstituted systems. Reconstitution of the anion exchange protein from human erythrocytes (band 3) into phospholipid vesicles was shown to have a protective effect on melittin lysis of the vesicles when compared to pure lipid vesicles. Low salt buffer was found to cause an inhibition of lysis in both proteoliposomes and pure lipid vesicles compared to salt buffer. High phosphate concentration did not seem to cause inhibition of lysis in the reconstituted system. However, an inhibition is observed in pure lipid vesicle control, which is contradictory to previous reports.


The synthesis and function of the Escherichia coli hemolysin and related RTX exotoxins. The RTX group of exotoxins represents a branch of a family of exoproteins produced by Gram-negative bacteria which share the properties of being secreted by a leader-independent pathway and a tandemly-repeated nine-amino-acid sequence that is responsible for calcium binding. The Escherichia coli hemolysin (HlyA) is the prototype for the RTX exotoxin family which includes the leukotoxins of Pasteurella haemolytica and Actinobacillus actinomycetemcomitans and hemolysins from four Gram-negative genera. A review of the genetics, synthesis, export and target cell reactivity of the E. coli hemolysin is given. An evolutionary tree of the RTX toxin family based on amino acid sequence similarity is presented.


Activation of Escherichia coli prohemolysin to the membrane-targetted toxin by HlyC-directed ACP-dependent fatty acylation. Hemolysin (HlyA) and related toxins of Escherichia coli and other Gram-negative pathogenic bacteria form membrane pores in cells of the host immune system, causing cell dysfunction and death. An insight into the mechanism by which HlyA is targetted to mammalian cell membranes was achieved by establishing in vitro activation of the non-toxic precursor proHlyA. By this approach we have discovered that conversion of proHlyA to the post-translational active HlyA toxin is determined by fatty acylation of proHlyA in an apparently novel process directed by the HlyC homodimer activator protein, and dependent upon the cellular acyl carrier protein (ACP). By further exploiting the in vitro activation system it is now possible to obtain direct evidence that HlyC binds to an internal recognition sequence in the proHlyA precursor, in this way providing specificity for the transfer to proHlyA of a fatty acid moiety carried by the ACP. It is possible that the fatty acid modification determines directly the binding of HlyA to mammalian membrane lipids, thus initiating the toxin interaction with the target cells.


The HlyB/HlyD-dependent secretion of toxins by gram-negative bacteria. Hemolysin (HlyA) and related toxins are secreted across both the cytoplasmic and outer membranes of Escherichia coli and other pathogenic Gram-negative bacteria in a remarkable process which proceeds without a periplasmic intermediate. It is directed by an uncleaved C-terminal targetting signal and the HlyD and HlyB translocator proteins, the latter of which are members of a transporter superfamily central to import and export of a wide range of substrates by prokaryotic and eukaryotic cells. Our mutational analyses of the HlyA targetting signal and definition for the first time of stages and intermediates in the HlyB/HlyD-dependent translocation allow a discussion of the hemolysin export process in the wider context of protein translocation.


Oligomer formation of staphylococcal alpha-toxin analyzed by electron microscopy and image processing. The 12S oligomeric form of Staphylococcus aureus alpha-toxin has been studied with electron microscopy after incubation of the toxin with membrane preparations or liposomes. The target material originated from human platelets. Different electron microscopic preparation techniques were used including negative staining, freeze-fracture and vitrification in liquid ethane. Analysis of micrographs with image processing methods revealed two groups of ring-like structures corresponding to alpha-toxin oligomers. One form measured 75 A in diameter and had a high stain density in the central protein deficient part while the other was larger with a diameter of 100 A and less stain accumulation in the center. The conditions under which the latter were formed suggest that this corresponds to an inactive loosely-bound form of the toxin. The high stain density in the smaller particle is consistent with the presence of a penetrating pore in this structure.


Specific and non-specific mouse protection induced by different chemotypes of the Pseudomonas aeruginosa lipopolysaccharides. Lipopolysaccharides (LPS) of Pseudomonas aeruginosa were studied by the mouse active, cross-protection test. The primary structure of O-specific polysaccharides (O-repeating units) of different chemotypes was determined and their cross-protective activity demonstrated. Low doses of LPS (0.1-1 micrograms) stimulated chemotype-specific protection against P. aeruginosa in mice. This immunity was associated with the primary structure of the LPS and it lasted for 14 days after the first or second immunization. High doses of LPS (10-100 micrograms) induced cross-protection against P. aeruginosa in mice. The cross-protective capacity was caused evidently by the secondary structure or conformation of LPS molecule, i.e. by the common conformational protective determinant. This cross-protection lasted for only 5 days after the first or second immunization.


Mechanism of the protective immunity against murine typhoid: persistence of Salmonella L forms in the liver after immunization with live-cell vaccines. Live-cell vaccines of Salmonella typhimurium, either a sub-lethal dose of a wild-type (strain LT2) or a high dose of its two-heptose Rd1 mutant (strain SL1004), induced acquired resistance to murine typhoid, which remained 180 days after immunization. Growth of S. typhimurium as a bacillary form ceased between days 30 and 60 of immunization, but L forms of this bacterium colonized the liver (the mean number of L forms in the liver: 600 L-forming units) even at 180 days post-immunization. In contrast, a high inoculum of either a Ra mutant (strain TV148) of strain LT2 or S. schottmülleri 8006 sharing the same O antigenic components with those of S. typhimurium induced only a short-lived protection in proportion to the number of L forms in the liver, and the protective immunity was lost before day 180. However, there was no significant difference in the salmonella-specific T-cell responses among groups of immunized mice on day 180 of immunization. A lethal infection with strain LT2 in mice which had been immunized 75 days previously with living cells of strain SL1004 resulted in a rapid clearance of the challenge inoculum, together with a rapid elevation of anti-S. typhimurium antibody responses. Thus, the present data suggest that the long-lived immunity conferred upon live S. typhimurium vaccines is attributable to the colonization of this bacterium in the liver as L forms and the ability to colonize the liver as L forms is independent of the chain length of salmonella O-antigens.


Immunogenicity and toxicity of lipopolysaccharide from Francisella tularensis LVS. Lipopolysaccharide (LPS) from the live vaccine strain of Francisella tularensis (F. tularensis LVS) was isolated and purified. The LPS did not stimulate lymphocytes from previously tularaemia-vaccinated individuals or lymphocytes from non-primed individuals. However, serum antibodies from tularaemia vaccinees reacted with the LPS whereas virtually no reactivity was found with antibodies from individuals not exposed to F. tularensis LVS. Antibodies of immunoglobulin class M displayed the antibody reactivity predominantly. The LPS failed to induce the mononuclear cell-derived cytokine interleukin-1 and only low levels of tumour necrosis factor were detected. Furthermore, no LPS endotoxin properties were found in galactosamine-treated mice or in the Limulus amoebocyte lysate assay. From these results it can be concluded that F. tularensis LVS possesses a lipopolysaccharide-like molecule, which does not exhibit properties of a classical endotoxin.


Phagocytosis of polymorphonuclear leukocytes by guinea pig peritoneal macrophages: effects of serum and temperature in vitro. The regulation of phagocytosis of neutrophils by peritoneal macrophages was studied in vitro. Peritoneal exudate cells (PECs) of guinea pigs were lavaged 15 h after the i.p. injection of thioglycollate medium and were cultured in chamber-slides. When PECs were cultured in RPMI 1640 medium in the absence of serum, approximately 20% of the macrophages phagocytized autologous neutrophils during 48-72 h of culture. Addition of guinea pig serum to the culture (2.5-20% v/v) suppressed the extent of the phagocytosis. The suppression was induced by globulin-rich ammonium sulfate fractions of the serum. Sera from rat, mouse, hamster, horse or calf also suppressed the phagocytosis, but fetal bovine serum (FBS) supported the phagocytosis, which was inhibited by globulin-rich Cohn fractions of bovine serum. The rate of neutrophil-phagocytosing macrophages was proportional to the rate of the pyknotic change of neutrophils. At a high temperature (42 degrees C), the autophagocytosis took place at 12 h of culture when fresh, but not heat-inactivated, autologous serum was added, implying that complement components may play a role in the hyperthermia-induced phagocytosis of neutrophils by macrophages. At 42 degrees C, ingested neutrophils did not show the pyknotic changes, indicating that intact neutrophils were ingested by macrophages.


Using quantitative coronary arteriography to redefine SPECT sensitivity and specificity. Previous studies looking at the sensitivity, specificity, and predictive accuracy of single photon emission computed tomography (SPECT) have been based upon the results obtained by visual interpretation of coronary arteriograms. Since the results of visual and quantitative determination of percent diameter stenosis have been shown to be statistically different, the results obtained from SPECT imaging when compared to quantitative methods for assessing coronary artery disease would be expected to provide a more correct assessment of sensitivity, specificity, and predictive accuracy. To determine the "true" sensitivity, specificity, and predictive accuracy of SPECT in diagnosing coronary artery disease, this study compared the results obtained in 44 SPECT images (20 thallium and 24 teboroxime) with the results obtained when quantitative coronary arteriography was used to analyze the coronary arteriograms. These 44 cases were then compared against 8 different definitions of significant coronary artery disease, varying from 30 to 80%, to yield 352 comparisons. The maximum specificity and predictive accuracy was found when 45% diameter stenosis was used to define the presence or absence of significant disease. At 45% diameter stenosis, SPECT imaging demonstrated an 86% sensitivity, 78% specificity, and 94% predictive accuracy with only 6% false positives. In 100% of the cases where 45% diameter stenosis was used to define the presence of disease and exercise failed to demonstrate ST segment changes or angina, when SPECT imaging demonstrated a perfusion defect(s), quantitative coronary arteriography agreed with SPECT imaging results.(ABSTRACT TRUNCATED AT 250 WORDS)


Multiple organ platelet sequestration, hemodynamics, and gas exchange in endotoxin shock and the effects of aspirin-terbutaline treatment. We studied the effects of two different drugs on multiple organ platelet sequestration, hemodynamics, and respiratory function during endotoxin shock. Twenty-eight sheep (four groups) were anesthetized and ventilated. Group AT-E received aspirin and terbutaline 30 min before and group E-AT 30 min after Escherichia coli endotoxin. Group E also received endotoxin but no drug treatment (shock controls), and group C received neither endotoxin nor drug treatment. There was a marked platelet trapping in the lungs and in the liver immediately after administration of endotoxin in groups E and E-AT, but after 4 hr it was less pronounced in group E-AT than in the endotoxin controls (P < 0.05). In the pretreated animals (group AT-E) there was no increase in platelet sequestration until almost 2 hr after endotoxin both in the lungs and the liver, but at the end of the study (240 min) there was no difference between the pre- and posttreated groups. No significant changes occurred in the kidneys and spleen in any of the groups. In groups E and E-AT the endotoxin infusion resulted in 200% rise in pulmonary artery pressure (PAP) and a sharp decrease in mean arterial pressure (MAP; 25-30%), respiratory compliance (CT; 50%), arterial oxygen tension (PaO2; 70%) as well as in oxygen delivery index (DO2; 30-40%) within 30 min. After 4 hr the PAP had decreased significantly in group E-AT, but remained high in group E (> 100% higher than in group C). Also MAP, PaO2, DO2 and CT improved slightly in group E-AT, while they remained low in group E.(ABSTRACT TRUNCATED AT 250 WORDS)


Sonographic evaluation of physiologic bolus volume in oral swallowing. Twenty-two nondysphagic normal subjects were sonographically studied to define the average volume of a physiologic fluid bolus. Several varying volumes (5, 10, 15, and 20 ml) of water were given to assess the average size of the swallowed bolus. At the onset of oral deglutition, when placed between the dorsum of the tongue and the groove of the hard palate, the bolus has an ellipsoidal shape, thus permitting sagittal, axial, and coronal measurements. Our results indicate that swallowed bolus volume rises proportionally to water bolus given up to 15 ml and that the average size of a physiologic fluid bolus is 7 ml.


Relationship of maternal smoking during pregnancy to placenta previa. Although maternal smoking during pregnancy is reportedly associated with placenta previa, its etiology is unknown. We examined this association by using North Carolina vital records of 1988 and 1989. Among women who smoked 0, 1-9, 10-19, and > or = 20 cigarettes per day during pregnancy, the prevalence of placenta previa at delivery was 3.8, 5.7, 6.3, and 6.7 per 1,000 singleton live births, respectively, in the entire population. However, after the potential confounders (maternal age, race, gravidity, parity, previous pregnancy terminations, previous cesarean section, and gestational age) were controlled by individual matching, the adjusted overall odds ratio (OR) was 1.29 (95% confidence interval [CI] 1.05, 1.58) with slight dose-response gradients. Our study indicates that, although maternal smoking during pregnancy might affect placenta previa, the magnitude is substantially smaller than previously reported. This association may be attributable to other factors, such as detection bias.


Clinical experience with Tc-99m labeled (N2S2) anti-melanoma antibody fragments and single photon emission computed tomography. We evaluated the imaging capability of murine Tc-99m-labeled antimelanoma Fab fragments in 12 patients with clinical stage II and III melanoma. Tc-99m-NRX118.7 antimelanoma Fab fragment, 10.0 to 27.2 mCi (370-1, 006 MBq), was injected IV 30 min after irrelevant nonspecific intact antibody and 5 min after intact specific antibody were given. In all patients, whole-body scans and spot views were obtained. Single photon emission computed tomography (SPECT) was additionally performed in eight of the patients. The procedure was well tolerated, and 31 of 38 known foci of melanoma were detected (sensitivity, 82%). SPECT aided in detecting and better localizing lesions in the head, neck, and chest. The specificity of the technique was satisfactory when interpretation was performed with a knowledge of normal sites of accretion and excretion of technetium-99m activity such as the kidneys and gut. In several instances, lesions were discovered by means of the antibody scan before detection by other methods, and in two instances, the lack of visualization on antibody scan of a palpable mass correctly indicated that no melanoma was present in the mass. Scan results in three patients led to alterations in patient care; including preventing aggressive surgical and nonsurgical treatments. Although these data are encouraging, evaluation in additional patients will be essential to determine the clinical utility of this antibody scan in the management of patients with melanoma.


Pathophysiologic considerations in carotid artery imaging: current status and physiologic background. Carotid endarterectomy now has an established place in the management of selected patients with carotid artery disease. This success rests in part on the invasive and non-invasive techniques available for imaging of both the pre- and postsurgical carotid artery. While contrast angiography has retained its place as a key presurgical imaging procedure, newer methods, including Doppler ultrasound, MRI angiography, SPECT, and PET scanning are providing additional anatomic, physiologic, functional, and biochemical information. An understanding of the complementary roles of these procedures is helpful to providers working to prevent strokes of carotid origin.


Impact of very low birthweight on the black-white infant mortality gap. In recent years, the rate of decline for the black infant mortality risk (IMR) has been slower than that for whites. The resultant widening in the black-white infant mortality gap has been accompanied by an increased percentage of very low birthweight (VLBW) infants (227 g-1,499 g) among black live births. Restricting our analysis to non-Hispanic black and white single live births, we used the 1983 national linked birth-death file to assess the relative contribution of VLBW infants to the black-white gap in IMR. VLBW occurred among 2.3% of all black live births and among 0.8% of all white live births. Deaths among VLBW infants accounted for 62.5% of the black-white gap in IMR. Although VLBW newborns represent a fraction of all live births in the United States, they account for almost two-thirds of the black-white gap in IMR. Since preterm delivery is associated with most VLBW infant deaths, our findings indicate the crucial need to identify strategies that reduce preterm births, among blacks in particular, to reduce significantly the infant mortality gap in the United States.


The use of cervical cytology to identify women at risk for chlamydial infection. Testing asymptomatic women for chlamydial infection is advocated for high-risk populations, but testing criteria in low-risk settings are less clear. To determine whether findings from Papanicolaou (Pap) smears could identify women at risk for Chlamydia, we studied 512 women, 18 to 50 years of age, seeking routine gynecologic care. The prevalence of positive cultures for Chlamydia was 4.7%. Three cytologic findings were independently associated with Chlamydia on logistic regression: transformed lymphocytes, polymorphonuclear leukocytes, and squamous metaplasia. The sensitivity and the specificity of the presence of any two of these three findings were 75% and 73.6%, respectively. The prevalence of Chlamydia if two findings were present was 12.2%, nearly three times the population prevalence. Certain findings on cervical cytology may be useful as an adjunct in preventive care for chlamydial cervicitis.


Agreement between patient self-reports and medical records for Pap smear histories. As part of a larger cervical cancer study, we tried to verify the Pap smear histories for 125 black women with cervical cancer. For 105 of the patients, we identified all possible providers for the five-year period before the calendar year of diagnosis. Agreement between the medical records and the patient reports was poor to fair (kappa = 0.34) for whether the patient had a Pap smear in the three-year period before diagnosis. Patients tended to report far more Pap smears than medical records confirmed. Important determinants of agreement were the number of Pap smears reported during the five-year period and the age of the patient. The older the patient and the more Pap smears reported, the larger the discrepancy between the medical record and her self-report. The medical records did not contain enough data for us to complete an investigation of the possible reasons for this disagreement. Our results suggest these implications: (1) clinicians should strongly consider performing Pap smears if they doubt a patient's screening history, and (2) Pap smear registries are required for reliable and efficient evaluations of cervical cancer control programs because neither the patient report nor medical records are adequate.


Prevalence of Chlamydia trachomatis infection among women in a multiphysician primary care practice. I screened 312 women, 18-45 years of age, presenting for routine gynecologic examination or prenatal care in a multiphysician primary care practice for Chlamydia trachomatis and Neisseria gonorrhoeae. I evaluated age, pregnancy, payment status, and presence of clinical cervicitis or gonorrhea as possible predictors of risk for chlamydial infection. Compared to culture, the direct immunofluorescent antibody (DFA) test used to screen for C trachomatis had a sensitivity of 70% and a specificity of 97%. By culture, the overall prevalence of chlamydial infection was 3.2% (confidence limits [CL] = 1.1-5.9) with a prevalence of 2.2% in nonpregnant women and 9.3% in pregnant women. Overall prevalence by the DFA test was 5.45%. Pregnancy status and youth were the significant predictors of risk for infection as determined by culture but not by Microtrak. Payment status, clinical cervicitis, and gonorrhea cultures were not useful predictors of increased risk. I discuss the implications of using culture, an imperfect "gold standard," for determining sensitivity, specificity, and prevalence.