Changes in the ultrastructure of the gills of the river lamprey, Lampetra fluviatilis (L.), during the anadromous spawning migration. Two types of mitochondria-rich cells were found in the interplatelet areas of the gills of the migrating river lamprey. Both cell types are thought to be responsible for ion-transport across the gills. In the fresh-run migrant the gills are dominated by large, flask-shaped cells which show some ultrastructural similarities with the teleost chloride cell and have been tentatively referred to as ion-excretory cells. During the spawning migration the ion-excretory cells are replaced by smaller, mitochondria-rich cells which are similar in structure to the presumed ion-transporting cells in the ammocoete gill. They lack the tubular, smooth-membraned endoplasmic reticulum so characteristic of the lamprey ion-excretory cell and the teleost chloride cell and have been referred to as ion-uptake cells. The ion-uptake cells are found during the stenohaline, freshwater phases of the lamprey's life history. Ion-excretory cells are present during the periods of the life cycle when the animal is euryhaline. The possibility that the ion-excretory cells are also responsible for ion-uptake in fresh water is discussed.


Some peculiar synaptic complexes in the first visual ganglion of the fly, Musca domestica. In the lamina ganglionaris, the first optic ganglion of the fly, the inventory of cell types as well as the patterns of their connections are well known from light microscopic investigations. Even the synaptic contacts are known with relative completeness. However, the structural details visible on electron micrographs are very difficult to interpret in functional terms. This paper concentrates on two aspects: 1) the synaptic complex between a retinula cell axon and four postsynaptic elements, arranged in a constant elongated array (it is suggested that all synapses in which the retinula cell is presynaptic are of this kind), and 2) the "gnarl" complex in which a presynaptic specialization in one neuron is separated from another neuron by a complicated glial invagination. The participation of glia at postsynaptic sites seems to be quite common in this ganglion. Occasionally it seems that a glia cell is the only postsynaptic partner facing a presynaptic specialization within a neuron.


Junctional structures in the crystalline cone of the crayfish compound eye. The junction in the crystalline cone in the compound eye of the crayfish Procambarus clarki is described. It consists of electron-dense pentahedrons arranged regularly all over the cytoplasmic surface of each membrane and dense material in the intercellular space. The cone is an entity formed by the secretion of the four cone cells so the junctional structures may serve a cohesive function. This junction is therefore designated as a coherent junction.


The nucleolar fibrillar centres in various cell types in vivo or in vitro. Nucleoli were studied in chick fibroblasts cultured in vitro, under normal or under experimental conditions, and in several mammalian cell types in vivo. All these cells frequently contain nucleoli with fibrillar centres. The nucleolar fibrillar centres are composed of fibrous material of low electron density and are always intimately associated with the dense fibrillar component. Their morphology is very similar to that analysed cytochemically in Ehrlich tumour cells. It therefore appears that they could be related to the nucleolar organizers as suggested in Ehrlich tumour cells.


Effects of d-propranolol and estradiol on the cervicovaginal epithelium. The cervicovaginal epithelium of neonatal mice produces a material with specific antigenic properties (CVA) and this material is produced in increased amounts after estradiol treatment. Using a cytochemical method, estradiol treatment was shown to result in an increase of adenylate cyclase activity in the same epithelium. When d-propranolol is injected together with estradiol, the increase in CVA is inhibited, while the hormone-induced proliferation of epithelial cells is not influenced. When adenylate cyclase activity is studied under identical conditions, the estradiol-promoted increase in enzyme activity is largely counteracted by d-propranolol. These findings would suggest that Adenosine 3"5"-cyclic monophosphate (cAMP) has a role in some, but not all, estradiol-mediated effects in the neonatal cervicovaginal epithelium.


Concentration of dopaminergic fibres in the marginal zone of the bird retina. Nerve fibres containing dense core vesicles of 100-160 nm diameter are concentrated in a narrow zone (near the ora serrata) of the marginal retina in the pigeon and the chicken. Synaptic junctions exist between terminals containing dense core vesicles and the most marginal ganglion cells; however, numerous fibres seem to end freely near the vitreous body or even penetrate the pars plana of the ciliary body. Histofluorescence demonstrates the aminergic nature of these fibres. Determination of catecholamines with the dansylation technique reveals six times more dopamine in the marginal than in the central retina, whereas the noradrenalin level is unchanged. The dopaminergic fibres originate in neurons of the innermost zone of the inner nuclear layer. The marginal localisation of these fibres apparently excluding any visual function seems rather to indicate a possible photoreceptor system involved in neuro-endocrine regulation.


The origin of reactive cells in retrograde and Wallerian degeneration. Experiments with intravenous injection of 3H-DFP-labeled macrophages. In order to examine the possible haematogenous origin of phagocytes in anterograde and retrograde degeneration, rabbit peritoneal macrophages were labeled in vitro with 3H-DFP and injected intravenously into host animals. Four or five days prior to the injection, the facial nerve was avulsed and the sciatic nerve ligated in five recipients. The animals were killed 24 h after the injection of the macrophages. Labeled cells were found in that part of the sciatic nerve which was mechanically damaged and in the liver and spleen but not in areas with retrograde or Wallerian degeneration. The possible interpretation of these findings is discussed.


The fine structure of fins and finrays of Tilapia mossambica (Peters). Light and electron-microscopic studies were carried out on the fins of the fish Tilapia mossambica (Peters). A detailed description is presented of the different skeletal components comprising the finrays. The mode of development of the hemisegments appears in several ways similar to that of fish scales. Each hemisegment is contained by an envelope of scleroblasts which secrete collagen fibres in a  unipolar fashion. Calcification takes place as a result of deposition of hydroxyapatite-like crystals between the collagen fibres. However, the orientation of these fibres is not as regular as that of the fibres occurring in scales.


Structure of the adenohypophysis in juvenile harp seal, Pagophilus groenlandicus. A study was made of the morphology of the adenohypophysis in immature harp seals and the fine structure of cellular components of the pars tuberalis, pars intermedia and pars distalis was described. The pars intermedia composed 8-15% of the hypophysis and contained colloid filled vesicles similar to those found in the other mammalian species. The pars distalis cells were grouped into more or less well defined regions, thus facilitating the correlation of cellular identification from both light and electron micrographs. Five chromophilic cell types were tentatively identified, one acidophil (putative somatotroph), four basophils (3 putative gonadotrophs and one cell type with the characteristics of both corticotrophs and thyrotrophs) and non-granulated "stellate" cells. The absence of a positive prolactin cell identification was thought to be due to the immaturity of the seals used in the study.


Formation of myoneural and myotendinous junctions in the chick embryo. Role of acetylcholinesterase-rich granules in the developing muscle fibers. The mode of formation of the myoneural and myotendinous junctions was investigated in the thigh muscles of the chick embryo. Myotendinous junctions first appeared on day 11 of incubation, whereas myoneural junctions developed on day 12. Intracellular AChE activity in the muscles increased by the 12th day of incubation, and decreased rapidly after the formation of the myoneural junctions. Light and electron microscopically, AChE activity was demonstrated in the nuclear envelope, sarcoplasmic reticulum, Golgi complex, and in large granules which appeared to be derived from the Golgi complex. Large granules showing an intense AChE activity accumulated in the sarcoplasm at the poles of the muscle fiber before the formation of myotendinous junctions. After the translocation of this intracellular enzyme onto the sarcolemma, most likely the result of an exocytosis of the granules, the myotendinous junctions were formed. The AChE-rich granules present in the middle of myotubes developed into spindle- or comma-shaped cisternae which were located in the sarcoplasm just below the presumptive motor endplates. The present results suggest that the transport of AChE-rich granules to the sarcolamma is the first step in the formation of myoneural and myotendinous junctions.


Morphological aspects of the hypothalamic-hypophyseal system. VI. The tanycytes: their relation to the sexual differentiation of the hypothalamus. An enzyme-histochemical study. Enzyme-histochemical methods were used to study the metabolic activity of specialized ependyma of the ventrolateral walls and floor of the third ventricle in young male and female rats during the "critical period" of sexual differentiation of the hypothalamus (one week after birth). Histochemical tests were conducted for glutamic dehydrogenase, lactic dehydrogenase, glucose-6-phosphate dehydrogenase, glycerophosphate dehydrogenase and NADH2-dehydrogenase. Enzyme activity was judged by cytospectrophotometry. All the data were treated statistically. It was found that the specialized ependyma of the ventrolateral wall and floor of the third ventricle (median eminence) in rats differed in their enzyme behaviour in males and females during the "critical period" of sexual differentiation of the hypothalamus. At the level of the arcuate nucleus (alpha2-tanycytes) and the medial part of the median eminence (beta2-tanycytes) the ependyma was characterized by similar indices of metabolic activity in males and females in the decisive terms of the "critical period" (days 3, 5, and 7). On day 5 metabolic activity of these cells was reduced both in the males and in the females. Prominent sexual differences in the intensity of the enzyme reactions studied were noted in the ependyma of the lateral parts of the median eminence (beta1-tanycytes) in the "critical period". On day 5 metabolic activity of beta1-tanycytes was reduced in males and increased in females. It is suggested that these differences are caused by the receptor nature of beta1 tanycytes and suggest their implication in the mechanisms of sexual differentiation of hypothalamus.


Water regulation in aestivating snails. Ultrastructural and analytical evidence for an unusual cellular phenomenon. Aestivating snails form abundant lamellate vesicles in the cells of the mantle collar, an epithelium known to regulate the rate at which water is lost from its surface. Since lamellate vesicles are much reduced in hydrated mantle tissue of recently stimulated animals it is tentatively concluded that the vesicles, and their contents, form a barrier to water movement within these cells. X-ray microanalysis of unfixed thin sections shows that there is a concentration gradient of ions within these cells in aestivating animals which is not present in stimulated snails.


The pit cell: description of a new type of cell occurring in rat liver sinusoids and peripheral blood. Pit cells--a new type of cell first described here and so named because they contain highly characteristic granules--are situated in the wall of rat liver sinusoids, and have hyaloplasmic pseudopodia intermingling with the microvilli of the parenchymal cells. The characteristic granules are mainly situated at one side of the nucleus, the other side showing organelle-free hyaloplasm. Pit cells are also found in portal tracts and in granuloma-like cellular aggregates. They also occur in rat peripheral blood, although there are morphological differences between cells in these two sites. Pit cells can be regarded as regular inhabitants of the sinusoidal wall, and therefore belong to the series of sinusoidal cells, i.e., the endothelial (Wisse, 1972), Kupffer (Widmann et al., 1972; Wisse and Daems, 1970; Wisse, 1974a, b), and fat-storing cells (Ito, 1973). Pit cells do not phagocytose and do not react to a great number of experimental conditions, to which endothelial and Kupffer cells do react (Wisse, 1972, 1974b). Mitosis has been observed in a pit cell. The function of pit cells remains obscure, but an endocrine function is suggested by the morphology of their highly characteristic granules.


Structural alterations of rabbit ovarian follicles after mating with special reference to the overlying surface epithelium. Rabbit ovarian preovulatory follicles and in particular the overlying surface epithelium were studied by morphological and ultrahistochemical means at different times after mating. By light microscopy an increase of cytoplasmic granules was found in the surface epithelium at the follicle apex 4 h after mating. The granules increased in amount and showed maximal accumulation 8-9 h after mating. They then disappeared at the same time as the connective tissue elements in the underlying tunica albuginea and theca externa disintegrated. Transmission electron microscopy showed that the membrane-bounded granules or dense bodies fused with one another and by 8 h after mating they often changed character and appeared more electron lucent. Furthermore, open communications were found between altered granules and vacuoles and between vacuoles and the extracellular space below the epithelium. Acid phosphatase reaction product was localized to the granules and Golgi cisternae. Not all the dense bodies were enzyme positive. At later stages, close to the time of follicle rupture, the epithelial cells were attenuated and thin, with only a few granules. By scanning electron microscopy it was found that the epithelial cells at the follicle apex increased in size approaching the time of follicle rupture and that their microvilli decreased in number and in size. At 8 h and later, the contours of intracellular granules could be visualized. The results of this study were similar to those found when rabbits were induced to ovulate by HCG-stimulation. This further strengthens the hypothesis that the surface epithelium contributes porteolytic enzymes which help to disintegrate the follicle apex prior to rupture.


The membrane systems of the cardiac muscle cell of Tmetonyx cicada O. Fabricius (Crustacea, Amphipoda). The membrane systems of the cardiac muscle cell of the amphipod Tmetonyx cicada (O. Fabricus) are described. The sarcolemma invaginates and forms a transverse network of tubules at the level of the Z band. Narrow longitudinal tubules branch from the network and connect to another transverse network of tubules at the H band level, where dyadic and triadic junctions are formed with the sarcoplasmic reticulum. Adjacent myofibrils are normally separated by a well developed double layer of the sarcoplasmic reticulum. In areas where the myofibrils closely approach the outer sarcolemma, peripheral couplings have been found at the level of the H band.


The ultrastructure of basal cells of rat and dog prostate. The ultrastructure of the basal cells of rat lateral and ventral prostate and of dog prostate has been studied. Basal cells from both species appear as undifferentiated cells, characterised by a lack of cytoplasmic organelles and a poorly developed Golgi complex and endoplasmic reticulum. The presence of cytoplasmic filaments and micropinocytosis is not considered to be sufficient evidence to assume any similarity to myoepithelium, as has been previously suggested. Basal cells are instead considered to be precursors of secretory epithelial cells.


The pineal gland of the mole-rat (Spalax ehrenbergi, Nehring). I. The fine structure of pinealocytes. The ultrastructure of pinealocytes of the mole-rat (Spalax ehrenbergi), a blind subterranean mammal living in complete darkness, was examined and compared with pinealocytes of other mammals. Two different populations of pinealocytes (I and II) were observed. They differed in general aspect. In location and especially in their content of cell organelles involved in synthetic processes. Mitochondria, ribosomes, granular endoplasmic reticulum, lysosomes, lipid inclusions and glycogen granules were present in the perikarya of pinealocytes of both populations. In the pinealocyte of population I some granular vesicles were occasionally observed in the cell body. Their presumed origin from the Golgi apparatus could not be clearly demonstrated. In the perikaryon of this pinealocyte, concentrations of ribosomes and of cisternae of the granular endoplasmic reticulum were constantly observed. These concentrations may indicate an intensive synthetic activity. Pinealocytes of population II were characterized by accumulations of proteinaceous material in some cisternae of the granular endoplasmic reticulum and between the two layers of the nuclear membrane. The origin of these peculiar elements is discussed.


A combined scanning and transmission electron microscopic study and electron probe microanalysis of human pineal acervuli. Untreated, decalcified and trypsinized acervuli from human pineal bodies were studied with the scanning and transmission electron microscope as well as by electron probe microanalysis. The mulberry-like acervuli are composed of a various number of spherical lobes (135-800 mum) between which clustered groups of globuli (4--14 mum in diameter) are observed. The acervular lobes are very probably formed by an aggregation of these globuli. Small round particles 125--500 A in diameter are observed on the surface of the pineal concretions. These are not influenced by either decalcification or trypsin treatment. The acervular mineral corresponds morphologically to hydroxyapatite. The electron probe microanalysis reveals the existence of calcium and phosphorus as main components of the acervuli. Small quantities of magnesium and strontium were also detected.


Ciliated neurons and different types of synapses in anterior hypothalamic nuclei of reptiles. The magnocellular paraventricular and supraoptic nuclei and the parvocellular preoptic and periventricular nuclei have been studied by light and electron microscopy in Emys orbicularis, Lacerta agilis and Elaphe longissima. The ultrastructure of cerebrospinal fluid (CSF)-contacting neurons was described in the preoptic and periventricular nuclei of Emys and Lacerta species. Single 9 X 2 + 0 cilia similar to those of the CSF-contacting dendritic terminals were found on perikarya of non CSF-contacting nerve cells, in all four investigated nuclei. The cilia project from funnel-like invaginations of the perikarya into the intercellular space. In the neurons of the nuclei studied, granular vesicles were found, their size being mainly 1,600 A in the paraventricular nucleus, about 1,800 A in the supraoptic nucleus, 1,100 A in the periventricular nucleus and 800 A, or up to 1,250 A in the preoptic nucleus. In general, the neurons possess synapses of the axo-somatic, axo-somatic spine, axo-dendritic and axo-dendritic spine types. In the supraoptic nucleus, multiple interdigitated synapses were observed. Presynaptically, eif different sizes (600 to 800 A, about 1,100 A, 1250 A, and up to 2,000 A) were found. It is discussed whether the above described 9 X 2 + 0 cilia may represent some kind of hypothalamic sensory structure that earlier physiological studies postulated to exist. The ciliated hypothalamic perikarya are considered by the authors to be a more differentiated form of the CSF-contacting neurons. The different types of synapses indicate multilateral connections of the nerve cells of the nuclei studied.


Cytophysiology and innervation of gonadotropic cells in the pituitary of the black molly (Poecilia latipinna). An electron microscopical study. In the male black molly, poecilia latipinna, morphological and functional aspects of the gonadotropic (GTH-)cells have been studied at the ultrastructural level. The cells exclusively occupy the ventral and lateral areas of the meso-adenohypophysis. In the black molly there is evidence of the presence of only one type of gonadotropic cell. In the GTH-cells of most specimens, the rough endoplasmic reticulum is weakly developed. The secretory vesicles are characterized by cores with varying diameters; this variation was not observed in the secretory vesicles of the other types of pituitary cells, except in the TSH-cells. After applying a histochemical method for the demonstration of polysaccharides, small black deposits appear in the core of the secretory vesicles of the GTH- and TSH-cells only; this indicates the glycoproteinaceous nature of the hormones produced in these cells. Male black mollies treated with methyl-testosterone have significantly smaller GTH-cells and a lesser number of secretory vesicles and mitochondria in these cells. GTH-cell activity in Poeciliinae may be thus influenced by androgens by means of a negative feed-back mechanism. The GTH-cells are innervated by both type A and type B neurosecretory fibres. There are indications that the type A fibres may originate from the pars lateralis cells of the nucleus lateralis tuberis; the origin of the type B fibres is uncertain.


The fine structure of polychaete septate junctions. Epidermal septate junctions of Nereis sp. and Cirriformia sp. fixed with OsO4 or glutaraldehyde/OsO4 display variable structure in electron micrographs. In transverse section the septa are often indistinct and obscured by opaque material that fills the junctional cleft. Septa (spaced at 180--280 A) are more clearly defined in slightly oblique transverse section; they exhibit an electron lucent center and appear to be linked by arms. En face views of the junction show a honeycomb pattern. Cytoplasmic faces of junctional membranes are backed with plaques opposite the septa. Lanthanum used as a tracer delineates junctional structure in negative contrast. In transverse section a chain-like lattice is present in the junctional cleft. En face vies show parallel rows of pleated elements often linked by arms into honeycomb arrays. Oblique sections demonstrate that these pleated elements are continuous with the chain-like lattice seen in transverse sections. Lanthanum does not pass entirely through the junction. Lanthanum reveals that the septa have a very intricate substructure, but it is difficult to visualize the architecture that could generate the various images presented by these junctions when seen in different orientations. However, it is clear that these junctions possess some features that are diagnostic of several supposedly different types of septate junctions in invertebrates.


"Axonal spheroids" in the spinal cord of normal rabbits. Within the gray matter and the white matter of the spinal cord of apparently healthy rabbits, myelinated and unmyelinated axonal swellings, so callled "xonal spheroids", occur. Most of the spheroids contain mitochondria, dense bodies, vesicles and fragments of the tubular or smooth endoplasmic reticulum. In myelinated spheroids the process of swelling is effected by slippage of the myelin leaflets. At the periphery of the unmyelinated parts of the spheroids, synapses are regularly found. The presynpatic terminal bouton is formed by the spheroid. A few myelinated and unmyelinated spheroids are packed with fine granular material while mitochondria are lacking. The axonal spheroids may represent a physiological, perhaps agedependent phenomenon.


Comparison of left and right ventricular function in acute myocardial infarction. Pulmonary arterial end-diastolic and mean right atrial pressures were compared in 25 patients with acute myocardial infarction and in one patient with unstable angina. No consistent relationship was observed between these pressures. Simultaneous ventricular function curves relating the stroke work of each ventricle to its respective filling pressure were constructed on 34 occasions, dextran infusion or diuresis being used to alter the filling pressure. The curves from each ventricle were described mathematically by a quadratic (parabolic) function as well as by a straight line function and then compared by canonical correlation analysis. Alterations in the left ventricular function curves occurred with and without depression or right ventricular function curves. These hemodynamic measurements demonstrate that acute myocardial infarction can alter the relationship between left and right ventricular function.


Caliber and distribution of normal coronary arterial anatomy. Selective coronary arteriograms of 125 patients with normal coronary arteries were reviewed to establish the caliber and distribution of normal coronary arterial anatomy. Measurements established the following normal values for coronary arterial caliber in right (R), (M), and left (L) inferior emphasis systems expressed in mm (+/-SEM): (See article). Significant differences in the caliber of right coronary arterial systems and left circumflex coronary arterial systems validate the separation of coronary arterial anatomy into right, mixed, and left inferior emphasis systems, depending upon the blood supply to the inferior wall of the left ventricle. Classification of the anatomical pattern into right, mixed, and left inferior emphasis systems is useful in the cardiac catheterization laboratory at the time of selective coronary arteriography. If the expected distribution of the coronary vessels is not found, then missing vessels must be sought out. A knowledge of the range of normal size for the coronary arterial tree should be of value in defining the severity of coronary arterial narrowing.


The clinical and angiographic spectrum of isolated, nondominant, left circumflex coronary disease. Sixteen of 994 patients with arteriosclerotic heart disease and dominant right coronary arteries had isolated left circumflex obstruction. Of these, 6 patients had significant (75%) narrowing in the main circumflex, 10 in 1 or the marginal branches and 1 in the atrioventricular groove branch. Angina was mild in 5, moderate to severe in 8, and unstable in 1. Four patients had prior myocardial infarction (MI), and 1 had a recent MI complicated by posterior papillary muscle rupture. The EKG was normal in 5, showed an MI in 2, LBBB in 1, RBBB in 2, ST-T wave changes in 3, LVH in 2, and atrial fibrillation in 2. Left ventricular angiography performed in the right anterior oblique projection revealed normal contraction in 9 patients, apical hypokinesis in 4, posterobasal hypokinesis in 1, and diffuse hypokinesis in 2. The left ventribular end diastolic pressure was normal in 11 patients and elevated in 5. The cardiac index was normal in 12 patients and reduced in 2. Isolated, nondominant, left circumflex coronary disease is an uncommon entity in symptomatic patients. However, when present, it may produce significant clinical and hemodynamic impairment.


Noninvasive diagnostic evaluation of the normal Beall mitral prosthesis. Phonocardiography and echocardiography were used to examine 20 patients with a normally functioning Beall disc mitral valve prosthesis. Phonocardiographic intervals were: Q-S1 interval 67 +/- 3 msec; A2-OC interval 118 +/- 8 msec. Maximal variation of the Q-S1 interval within one examination was 21 +/- 2 msec, for A2-OC interval it was 31 +/- 5 msec. Echocardiographic disc velocities were: opening velocity 296 +/- 30 mm/sec, closing velocity 414 +/- 44 mm/sec. Maximal variation of the opening velocity was 126 +/- 25 msec; maximal variation of the closing velocity was 334 +/- 57 msec. Abnormal poppet function was suspected in one patient with unusual prolongation and variability of A2-OC interval.


Treatment of angiographically produced cord seizures by intra-arterial diazepam. 10 MG OF Diazepam administered into the lumbar artery supplying the artery of Adamkiewicz abolished cord seizures produced by accidental flooding of the cord with a high concentration of contrast material. Selective intra-arterial Diazepam is a safe and effective method of controlling cord seizures.


Coronary artery dissection - a complication of cardiac catheterization without sequelae: case report and review of the literature. This report describes an acute right coronary artery dissection occurring during diagnostic cardiac catheterization. Following catheter manipulation in the vicinity of the aortic valve, the patient complained of mild chest discomfort and had transient electrocardiographic evidence of acute inferior wall myocardial infarction with runs of 2:1 atrioventricular block. Within 5 min, the EKG reverted to precatheterization appearance, and the patient was asymptomatic. Coronary angiography revealed a dissection of the proximal vessel without obstruction. The patient had no clinical sequelae while monitored in the intensive care unit. The patient underwent elective aortic and mitral valve replacement. The area of the dissection was directly visualized, and no abnormality was noted. We review the literature of spontaneous and iatrogenic coronary artery dissections with regard to pathology, diagnosis, and prognosis, and make recommendations for therapy.


Pulmonary arteriography in congenital heart disease. Pulmonary outflow tract obstruction may occur at subvalve, valve, or pulmonary artery level. Selective ventriculography will usually define the intracardiac obstruction (whether valve, subvalve, or both) and may define pulmonary arterial abnormalities. Increasing experience in the surgical management of patients with tetralogy of Fallot and other conotruncal abnormalities characterized by significant pulmonary outflow tract obstruction suggests that preoperative recognition of pulmonary arterial stenosis is essential to the successful operative management of these patients (1-4). Because of the anatomicospacial relationships of the pulmonary arteries in "simple" (tetralogy of Fallot) and complex conotruncal malformations, selective ventriculography may not invariably provide sufficient detail about the morphologic state of the pulmonary arteries. Similarly, even selective pulmonary arteriography in the standard anterioposterior, lateral, and oblique views may not always allow accurate anatomic assessment of these vessels. Therefore, we wish to document a maneuver that has proved valuable in the assessment of pulmonary arteries during selective pulmonary arteriography. This maneuver was originally suggested to Peter M. Olley by Dr. L. M. Bargeron, Jr., and the surgical valve obtained from this angiographic view was stressed by Dr. John Kirklin in his John Keith lecture at the Canadian Cardiovascular Society (5). Although it is being used at some cardiovascular centers, we feel its application warrants this report.


Induction by ouabain of hemoglobin synthesis in cultured Friend erythroleukemic cells. Induction of erythroid differentiation in ouabain-resistant murine erythroleukemia cells by ouabain is reported. Ouabain induction results in the appearance of hemoglobin-containing cells 12-24 hr earlier than induction of the same clone by dimethyl sulfoxide. The levels of globin mRNA after ouabain induction are similar in amount to the globin mRNA levels observed after induction by dimethyl sulfoxide. The concentration of ouabain required to induce hemoglobin synthesis depends upon the K+ ion levels in the culture medium. Lowering the extracellular K+ ion concentration 2-4 fold reduced by 10-40 fold the ouabain concentration necessary for the induction of hemoglobin synthesis. In low K+ medium (1.8 mM), ouabain is an effective inducer of hemoglobin synthesis at a concentration of 0.02 mM. This K+ effect is specific for ouabain induction, since induction by other inducers, such as dimethyl sulfoxide and dimethyl acetamide, does not exhibit this marked sensitivity to the levels of K+ ions in the culture medium. These results suggest that the binding of ouabain to the plasma membrane enzyme, Na/K ATPase, is required for the induction of erythroid differentiation by ouabain. A small but significant proportion of wild-type, ouabain-sensitive cells also can be induced by ouabain, below ouabain concentrations that are toxic to these cells. The observation that the binding of ouabain to the Na/K ATPase induces hemoglobin synthesis suggests that changes in the intracellular concentration of K+ ions may be involved in the control of erythroid differentiation in Friend erythroleukemic cells.


Transfer of murine intracisternal A particle phenotype in chloramphenicol-resistant cytoplasts. Murine intracisternal A particles have a number of properties which are common to known RNA tumor viruses, but horizontal transmission has not been previously demonstrated. The apparent absence of infectivity may be related to the failure of these particles to be released from cisternae of endo-plasmic reticulum. Previous biological studies using isolated, purified A particles have been compromised by the fact that the isolation procedure requires small amounts of nonionic detergent. Using some techniques of somatic cell hybridization, we have assessed the capacity for A particle genome transfer from positive to negative cells. Since it has been previously shown that some chloramphenicol-resistant cell lines can transfer this resistance in the cytoplasm, we have used this characteristic as a marker for cytoplasmic fragments. Mouse cells containing A particles were mutagenized, and clones resistant to chloramphenicol were selected; by enucleating these cells and fusing the resultant cytoplasts to each of two recipient mouse cell lines negative for A particles, it is possible to identify clones of cells known to be the product of a fusion event between a cytoplast and a whole cell (cybrids). Under these conditions, intracisternal A particles appear in the cybrid clones as a phenotypic trait that has not been segregated over at least 60-80 cell generations.


A model for chromatin based upon two symmetrically paired half-nucleosomes. We propose that the basic unit of chromatin is constructed of two isologously paired heterotypic protein tetramers each containing one molecule of H2A, H2B, H3, and H4 histone. These proteins form a core that holds 140 base pairs (bp) of DNA in a single left-handed, non-interwound DNA super-coil approximately 95 bp in circumference, creating a nucleosome particle (DNA and protein) organized about a dyad axis of symmetry. Such a nucleosome can open up into its separate half-nucleosomes to allow genetic readout without requiring histone displacement.


Cooperative alignment of nu bodies during chromosome replication in the presence of cycloheximide. 50% of control DNA is resistant to staphylococcal nuclease after digestion in isolated nuclei, while only 25% of the labeled DNA made in the presence of cycloheximide is resistant to nuclease. Nevertheless, cycloheximide DNA is folded into normal chromosomal subunits as evidence by the observation that it generates nuclease limit-digest DNA fragments that are indistinguishable from controls. These results indicate that cycloheximide chromatin is associated with half the number of normal nu bodies. These nu bodies are probably recycled from the parental chromosome. Partial nuclease digestion of cycloheximide chromatin reveals that a normal pattern of monomer and multimer DNA fragments is generated up to octamers. The data are consistent with the idea that in the presence of cycloheximide, recycled parental histones become cooperatively aligned along the daughter double helices.


Studies on the mode of segregation of histone nu bodies during replication in HeLa cells. Two models were tested for the mode of distribution of histone nu bodies at the replication fork. The replication fork was labeled by brief incubation of cells with 3H-thymidine. Nuclei were isolated and digested with low levels of micrococcal nuclease, and the kinetics of cleavage of the pulse-labeled chromatin DNA were compared to the kinetics of clevage of perental chromatin DNA. In chromatin labeled for 30 sec to 10 min, the rate of cleavage of the pulse-labeled region into monomeric nu body-sized units exceeded the rate of cleavage of parental chromatin by a factor of 2, but did not approach the predicted value of 5-6 for random segregation. This value dropped to 1.6 in 15 min and was equivalent to perental chromatin in 20 min labeling experiments. DNA synthesized in the presence of cycloheximide was also digested at twice the rate of parental chromatin DNA. A Poisson analysis of the kinetics of cleavage by micrococcal nuclease further confirmed these observations. The predicted difference in the rate of production of monomeric, dimeric, and trimeric deoxyribonucleoprotein units was very similar to the experimental values of both total chromatin and nascent chromatin. Thus the nu body spacings in newly replicated chromatin closely approximate those in parental chromatin. These results agree well with a conservative or nondispersive model of nucleosome distribution in which the proteins are associated with one of the two daughter chromosomes during replication.


DNA-dependent in vitro synthesis of fibosomal proteins, protein elongation factors, and RNA polymerase subunit alpha: inhibition by ppGpp. We have previously shown that the synthesis of ribosomal proteins (r proteins) in E. coli cells is under stringent control (Dennis and Nomura, 1974). Since guanosine tetraphosphate (ppGpp) has been implicated in stringent control, we examined the effects of ppGpp on the in vitro synthesis of r proteins directed by DNA from transducing phage lambdafus3 and lambdarifd18. lambdafus3 carries genes for protein elongation factors EF-Tu and EF-G, and RNA polymerase subunit alpha, in addition to genes for approximately 27 r proteins. lambdarifd18 carries genes for EF-Tu, RNA polymerase subunits beta and beta1, and a set of rRNAs, in addition to genes for approximately five r proteins. We have shown that low concentrations of ppGpp (0.2-0.3 mM) specifically inhibit DNA-dependent r protein synthesis in this system, and that this inhibition takes place directly, rather than as a consequence of the inhibition of rRNA synthesis by ppGpp. In addition, we have also shown that ppGpp inhibits the synthesis of EF-G, EF-Tu, and RNA polymerase subunit alpha, as well as rRNAs.


hnRNA in HeLa cells: distribution of transcript sizes estimated from nascent molecule profile. In HeLa cells, about half the hnRNA is synthesized from transcription units which are less than 5000 bases in length, although over 80% is larger than the average mRNA. This conclusion was derived from a quantitative analysis of the nascent chain sedimentation profile.


Evidence for a foot-inhibiting substance in hydra. Crude extracts of hydra contain a substance or substances which specifically inhibit foot formation in regenerating hydra. This foot inhibitor(s) is probably of low molecular weight, and it is present in the animal in an inactive, structure-bound form as a gradient from foot to head. The foot region contains 60% of this inhibitor in a 7-8 fold higher concentration than the other regions. The foot inhibitor was purified chemically from the head activator (Schaller, 1973) and the 'head' inhibitor (Berking, 1974). It is suggested that the substance under investigation is a new morphogen, responsible for foot inhibition in hydra.


Intercellular bridges in lizard oogenesis. Study of the germinal epithelium in the adult lizard shows that the germ cells constitute clusters of synchronized cells interconnected by intercellular bridges. Such bridges interconnect oogonia as well as early meiotic prophase oocytes (zygo-pachitene). Besides true intercellular bridges in oocytes, there are plasma membrane interruptions forming large zones that ensure cytoplasmic continuity between adjacent cells. In early diplotene, germ cells are isolated. Later, during auxocytosis, when the polymorphic follicular epithelium around the oocyte starts differentiating, intercellular bridges appear between the follicle cells and oocyte. No relationship is observed between the intercellular bridges found in the germinal epithelium and those found between the follicle cells and oocyte.


1-Hydroxy-2-tert-butyldimethylsilyl-sn-glycero-3-phosphorylcholine. A useful intermediate in the synthesis of short acyl chain 1-acyl-sn-glycero-3-phosphorylcholines. The synthesis of 1-acyl-sn-glycero-3-phosphorylcholines in particular those containing short fatty acyl chains are described. The method involves the use of 1-acyl-2-tert-butyl-dimethylsilyl-sn-glycero-3-phosphorylcholines which can be readily prepared by reacting hens' egg yolk 1-acyl-sn-glycero-3-phosphorylcholines with tert-butyldimethylchlorosilane with imidazole as catalyst and dimethylformamide as solvent. Deacylation of the 1-acyl-2-tert-butyldimethylsilyl-sn-glycero-3-phosphorylcholines with saturated anhydrous potassium carbonate in methanol yields the 2-tert-butyldimethylsilyl-sn-glycero-3-phosphorylcholine. Reacylation of the 2-tert-butyldimethylsilyl-sn-glycero-3-phosphorylcholine with fatty acyl anhydride in the presence of 4-dimethylaminopyridine in anhydrous chloroform followed by removal of the tert-butyldimethylsilyl protecting group by treatment with dry hydrogen chloride gas in anhydrous chloroform at 0 degrees yields the desired 1-acyl-sn-glycero-3-phosphorylcholine. Various facets of the reactions involved in developing the synthetic procedures in this study are discussed.


Application of enantiomeric 2-sn-phosphatidylcholines in interfacial enzyme kinetics of lipolysis. Two enantiomeric 2-sn-phosphatidylcholines containing hexanoyl and dodecanoyl acyl chains have been synthesized, enabling the study of the action of phospholipase A2 (EC 3.1.1.4) at lipid-water interfaces characterized by identical physico-chemical properties. Monolayer kinetics and bulk kinetics in the presence of Triton X-100 micelles were studied but the interpretation of the results is impeded by the fact that interfacial saturation conditions cannot be reached. In contrast, the use of the substrate analog n-tetradecylphosphorylcholine allows the determination of the interfacial kinetic parameters kcat and K*m. Dodecanoic acid is released from the most susceptible isomer about 13 times more rapidly than hexanoic acid from the stereoisomer in spite of the higher K*m of the former. The results are discussed in terms of the particular active site architecture and the possible influence of the "quality of the interface" on the kinetic parameters.


An improved synthesis of 1-0-[3H] alkyl-2-acyl-sn-glycerol-3-phosphorylethanolamine with an unsaturated acyl chain. A method is described for the synthesis of 1-0-[9', 10'-(3)H2] octadecyl-2-octadecenoyl-sn-glycerol-3-phosphorylethanol-amine, starting from rac 1-0-octadecen-9'-ylglycerol. The sn-1-alkyl enantiomer is obtained by an enzymatic reaction involving deacylation of rac 1-0-octadecen-9'-yl-2-octadecenoyl-glycerol-3-phosphoryl-N-(tert.-butyloxycarbonyl) ethanolamine with phospholipase A2. The resulting lyso compound is tritiated with 3H2 in the presence of platinum catalyst and reacylated with oleoyl anhydride to yield the final product.


Synthesis of monophytanyl ether analogues of lysophosphatidic and lysophosphatidyl glycerol. The chemical synthesis of 3-O-phytanyl-sn-glycero-1-phosphoric acid (monophytanyl ether analogue of lysophosphatidic acid) was effected by condensation of 1-iodo-2-O-benzyl-3-O-phytanyl-sn-glycerol with silver di-p-nitrobenzyl phosphate in anhydrous toluene followed by catalytic hydrogenolysis of the resulting phosphotriester to remove the benzyl and p-nitrobenzyl groups. Synthesis of 3-O-phytanyl-sn-glycero-1-phosphoryl-1'-sn-glycerol (monophytanyl ether analogue of lysophosphatidyl glycerol) was carried out by conversion of the above phosphotriester to the monosilver salt of the suitably blocked lysophosphatidic acid which was condensed with 1-iodo-2-O-t-butyl-3-O-benzyl-sn-glycerol. Removal of the protecting aromatic and t-butyl groups from the resulting blocked triester intermediate gave the desired phytanyl ether analogue of lysophosphatidyl glycerol. Both lyso analogues were isolated as analytically and chromatographically pure potassium salts. Their physical properties and behavior towards acid hydrolysis are described.


Isosteres of natural phosphates. 4. The synthesis of phosphonic acid analogues of phosphatidic acid and acyldihydroxy acetone phosphate. The chemical synthesis of 3,4-diacyloxybutyl-1-phosphonic acids having palmitoyl and oleoyl groups is described. These were prepared by reaction of the appropriate 3,4-diacyloxybutyl-1-bromide with tris(trimethylsilyl) phosphite followed by mild hydrolysis of the trimethyl-silyl groups from the phosphonic acid. Also reported is the preparation of 4-palmitoyl-3-oxobutyl-1-phosphonic acid by the acylation of 4-hydroxy-3-oxobutyl-1-phosphonic acid. This latter compound is an isosteric analogue of acyldihydroxyacetone phosphate.


Mass spectral identification of 2-(O-acyl)hydroxy fatty acid esters in the white portion of the rabbit Harderian gland. A major lipid component of white portion of the rabbit harderian gland has been shown to be a mixture of 2-(O-acyl)hydroxy fatty acid esters. The fatty acid moieties in this lipid class are exclusively saturated and range in chain length from C14:0 to C22:0, with C16:0 being the major component (65%). The fatty alcohols are also saturated and composed primarily of C20:0, C21:0, and C22:0 chains. The hydroxy fatty acids are composed of C14:0, C15:0, and C16:0 and mass spectroscopy combined with chemical techniques placed the hydroxyl group at the 2-carbon. 2-(O-acyl)Hydroxy fatty acid esters are not found in the pink portion of the rabbit harderian gland nor have they been reported to occur in harderian glands or other species.


Novel lipids of Butyrivibrio spp.

Novel lipids of Butyrivibrio spp. (1) An analysis has been conducted of the lipids present in three obligately anaerobic bacteria isolated from the ovine rumen belonging to the genus Butyrivibrio. Two of these organisms are rich in phospholipase (A1 + A2) activity, and appear to be different strains of the species fibrisolvens. (2) The only N-containing lipids comprise N-acyl-phosphatidylethanolamine occurring as a minor component in all organisms and a new lipid, diglyceride galactosylphosphorylethanolamine in one of these. (3) All three organisms contained the n-butyryl ester of phosphatidyl-glycerol and in one this represented the major phospholipid present. Valeryl, iso-valeryl, propionyl and myristoyl esters of phosphatidylglycerol were also detected. (4) Two organisms contained glycerylphosphorylgalactosyldiglyceride and one of these also contained a large proportion of a less polar galactophospholipid which is probably a diacyl derivative of the former lipid. (5) All three organisms contained monogalactofuranosyl diglyceride and from one a n-butyryl ester of this galactolipid was isolated. (6) In all of the lipids examined the "diglyceride' moiety consisted almost entirely of plasmalogenic diglyceride (alk-1-enyl, acyl, glycerol).


Configurational analysis of long-chain alkanediols. Long-chain 1,2-alkanediols can be separated into their enantiomers by thin-layer chromatography of the bis-L-acetylmandelates. The method is also applicable to the separation of enantiomeric 1,3-alkanediols. Both 2-hydroxy fatty acids and 1,2-alkanediols derived from diester waxes of rat skin have the D-configuration. The D-enantiomer of 2DL-1,2-octadecanediol is preferentially utilized by myelinating rat brain in the formation of choline phospholipids having a 1,2-octadecanediol backbone. The D-configuration of the chiral center at carbon-2 of 2-acyl-1,2-alkanediol phosphocholine corresponds to the configuration at carbon-2 of 1,2-diacyl-sn-glycero-3-phosphocholine.


Intracellular phospholipid transfer and exchange. The intracellular transfer of phospholipids in rat liver was studied. The factors affecting the transport and the role of phospholipid transfer proteins in this process were investigated. The procedure was based upon the labelling of microsomal phospholipids with either 14C or 32P, and incubation with unlabelled mitochondria in an in vitro system. The re-isolated mitochondria became labelled demonstrating an exchange of phospholipid between the two membranes. The transfer was stimulated by the addition of high-speed supernatant, was unaffected by the addition of ATP, but did not occur at 0 degrees C. Phospholipid transfer between liposomes and mitochondria was shown to occur, suggesting that the participation of natural membranes is not required for transfer to take place. The conditions required were found to be similar, and the high speed supernatant promoted transfer to the same extent as when labelled microsomes acted as the donor. The transfer activity of the high-speed supernatant was abolished by treatment with sulphydryl-blocking agents. Beef supernatant was adjusted to pH 5.1 and the activity remained in the supernatant. The pH 5.1 supernatant was applied to a Sephadex G-75 column and two active fractions were collected. The higher molecular weight fraction contained several proteins and stimulated the transfer of phosphatidylcholine and phosphatidylethanolamine. The lower molecular weight active fraction contained a protein which specifically stimulated the transfer of phosphatidylcholine.


Effect of unsaturated lipids on the bile flow and biliary excretion of cholesterol and bile salts in rats. When rats were fed safflower oil or coconut oil for 30 days, or soyalecithin (EPL) or egg phospholipids for 7 days, the rates of bile flow, concentration of cholesterol in the bile as well as unsaturation in the biliary phospholipids were markedly higher in the animals receiving the more unsaturated lipids. It is concluded that feeding of lipids containing polyunsaturated fatty acids effects an increase in the unsaturation of the biliary phospholipids and thereby causes increased excretion of cholesterol through the bile.


Asymmetry of the lipid-bilayer of Sindbis virus. The organization of the lipid bilayer of the enveloped Sindbis virus has been studied. In the model membrane which consists only of two virus specific glycoproteins and host derived lipids the latter were radioactively labelled with 14C-palmitic acid by prelabelling their BHK 21 host cell lipids. The purified virus particles were submitted to neuramidase, bromelain and combromelain-neuraminidase treatment. It could be demonstrated that N-acetyl neuraminic acid residue of the total hematoside present in the virion is hydrolyzed by neuraminidase leaving the particles fully intact. Proteolysis of the spikes leads to particle aggregation yet an unchanged hematoside content. This was fully transformed into ceramidelactoside by subsequent neuraminidase treatment. The analyses of the ceramide species present in hematoside of the control particles and ceramidelactoside derived thereof by neuraminidase hydrolysis are in very close agreement. From these experiments it is concluded that all hematoside molecules are organized in the outer half of the bilayer of the envelope.


Calorimetric behaviour of individual phospholipid classes from human and bovine erythrocyte membranes. The predominant phospholipids from human and bovine erythrocytes were isolated and purified from ghost preparations. Their gel to liquid-crystalline phase transitions were detected by Differential Scanning Calorimetry. In addition calorimetric experiments were performed on phospholipid mixtures which mimic the inner or outer monolayer of both membranes. From the results it can be concluded that, ignoring the presence of cholesterol, there can be a marked difference in fluidity between the outer and inner monolayer of erythrocyte membranes.


Detection of lipid phase transitions by surface tensiometry. A technique for the detection of lipid phase transitions is described, which involves measurement of the surface tension as a function of temperature. In the case of insoluble lipids, such as dipalmitoylphosphatidylcholine (DPPC) the lipid is spread as a multibilayer film on an aqueous substrate, while in the case of water-soluble lipids such as lysophosphatidylcholine (LPC) the surface tension of aqueous sols is measured. Surface tension at the interface, is monitored using a Wilhelmy plate while the temperature is continuously varied. Discontinuities or changes in slope in the surface tension-temperature (gamma-T) curve reflect phase transitions in the lipid. In the case of DPPC, the technique has been used to demonstrate the well-known gel-liquid crystalline thermal transition. This occurs at 36-38 degrees C in the multibilayer films; in bulk DPPC-water dispersions the transition is at 41 degrees. Cholesterol has the effect of lowering the thermal transition and broadening the temperature range. In films containing DPPC-cholesterol at a molar ratio of 2:1 or less, the transition is not present. These results are in agreement with a large number of previous studies of this system. In the case of LPC sols, a phase transition at about 70 degrees was detected when the concentration of SPC was close to the critical micelle concentration (CMC) at 70 degrees. This transition appears to reflect an increase in the equilibrium constant for micelle formation at this temperature. At higher concentrations of LPC a transition at 30 degrees, corresponding to a gel-liquid crystalline transition, was also detected. A complete description of gamma as a function of concentration and temperature in the range 10(-7) to 10(-3) g cm-3 and 20 degrees to 80 degrees has been obtained for LPC sols. The CMC varies from 6 X 10(-6) g cm-3 at 20 degrees to 10(-5) g cm-3 at 80 degrees.


Reaction of amino-phospholipids of the inner mitochondrial membrane with fluorodinitrobenzene and trinitrobenzenesulfonate. Mitoplasts from rat liver mitochondria and ETPH particles from beef heart mitochondria were reacted with TNBS and FDNB in sucrose-mannitol-bicarbonate buffer pH 8.2 (BUFFER A) and in sodium chloride-bicarbonate buffer pH 8.5 (buffer B). Mitoplasts and ETPH particles are more stable in buffer A and very little hydrolysis of phospholipids occurs during the reaction period. In this buffer TNBS reacts to a lesser extent with phosphatidylethanolamine (PE) than does FDNB. The data suggests that with mitoplasts 65% of the total PE is localized on the outer surface of the membrane. With mitoplasts the labeling of membrane proteins is much more extensive with FDNB and suggests that 66% of the proteins are localized on the inner membrane surface. Thus a dual type of asymmetry occurs in the mitoplast membrane with more PE localized on the outer surface and more protein localized on the inner surface. In buffer B, extensive degradation of the dinitrophenylated and trinitrophenylated PE and LPE occurs to yield DNP-GPE and TNP-GPE respectively. DNP-GPE and TNP-GPE are degraded by a phosphodiesterase to DNP-ethanolamine and TNP-ethanolamine. When ETPH particles are labeled with TNBS and FDNB, washed, and incubated in buffer A and buffer B, a resynthesis of TNP-PE and DNP-PE occurs in buffer A by acylation of TNP-LPE whereas DNP-PE continues to be formed, primarily from DNP-GPE. These studies provide evidence for an asymmetric arrangement of PE in the inner mitochondrial membrane and demonstrate the presence of membrane-bound phospholipases which act on dinitrophenylated and trinitrophenylated amino-phospholipids. A membrane bound phosphodiesterase is also present which degrades dinitrophenylated or trinitrophenylated GPE. The degradative reactions prevail in bicarbonate-NaCl buffer B whereas acylation reactions prevail in sucrose-mannitol buffer A.


Stearoyl paratoluenesulfonate. A powerful acylating agent for lipid synthesis. The utility of the mixed carboxylic-sulfonic acid anhydride stearoyl p-toluenesulfonate as a powerful, mild acylating agent for lipid synthesis is shown by the synthesis of rac 1,2-distearoyl-3-iodopropane, lecithin and a spin-labeled choline derivative from the corresponding alcohols. The method constitutes a significant improvement of earlier acylating methods.


Preparation of 1-acyl-2-succinyl glycero-3-phosphorylcholine and evidence against its involvement in succinate dehydrogenase action. 1-Acyl-2-succinyl glycero-3-phosphorylcholine (GPC) was synthesized and its properties described. Although 1-acyl-2-succinyl GPC is a good substrate for succinate dehydrogenase, experiments on the incorporation of [2,3-14C] succinate into mitochondrial lipids gave no evidence to indicate that it is an intermediate in the enzymic oxidation of succinate to fumerate, as has been suggested earlier.


The effect of cholesterol on the viscosity of protein-lipid monolayers. The addition of cholesterol to a layer of lipids in a membrane structure is generally believed to result in an increase in the viscosity of the layer. We have shown that cholesterol and two other monolayer-forming lipids markedly decrease the viscosity of a serum albumin monolayer at the decane-water interface, a model membrane system. However, when the protein monolayer already has a surface active lipid component present, the effect of added cholesterol depends upon the other substance. When the albumin monolayer contains tristearin, added cholesterol increases the viscosity. When the lipid is octadecanol, cholesterol decreases the viscosity. The dependence of the change in interfacial viscosity due to cholesterol upon the original composition of the interfacial layer may be useful for characterizing the composition of layers of unknown composition, e.g. some natural membranes.


Studies on the interaction of cholesterol with diester- and dietherlecithin. The lamellar repeat distances of aqueous dispersions of rac-1,2-dioctadec-9'-cis-enyl-glycero-3-phosphorylcholine (dietherlecithin) and 1,2-dioctade-9'-cis-enoyl-sn-glycero-3-phosphorylcholine (diesterlecithin) have been measured by X-ray diffraction as a function of water concentration. The point of maximum hydration was found to be 43% (w/w) for dietherlecithin and diesterlecithin respectively; the corresponding lamellar repeat distances being 62.3 å and 60.5 ã. Incorporation of cholesterol above maximum hydration results in the initial increase in the lamellar repeat distance with a maximum around cholesterol concentrations of 25 and 33 mol% for dietherlecithin and die diesterlecithin respectively. The apparent partial specific volumes fo the two lecithins and for lecithin--cholesterol mixtures in sonicated aqueous dispersions were measured. Values of 1.024 cm3-g-1 and 0.987 cm3-g(-1) were obtained for diether- and diesterlecithin, respectively, at 20 degrees C. Diesterlecithin-cholesterol mixtures showed a very small change in partial specific volume while mixtures of dietherlecithin-cholesterol showed a very marked decrease with increasing proportions of cholesterol. From these data a series of structure parameters are derived for the two lecithins and possible implications for the nature of the lecithin-cholesterol interaction are discussed.


Raman studies of the C-H and C-D stretching regions in stearic acid and some specifically deuterated derivatives. Raman spectra of polycrystalline stearic acid-do, stearic acid-d35, 16:16-d2-18:18:18-d3-stearic acid, 18:18:18-d3-stearic acid, 17:17-d2-stearic acid, 17-d1-stearic acid, 16:16-d2-stearic acid, 12:12-d2-stearic acid and 12-d1-stearic acid have been obtained for the region containing the C-D and C-H stretching vibrations. Assignments of the methyl, methyl-d3, methylene, methylene-d2 and methylene-d1 stretching vibrations are discussed.


Mass spectrometry of sterols. Electron ionization induced fragmentation of C-4-alkylated cholesterols. The electron impact ionization of C-4-alkylated cholest-5-en-3beta-hydroxysterols has been investigated. The mass spectra of the C-4-alkylated cholesterols contain a number of ions in the high mass region for which analogous ions are not found in the spectrum of cholesterol. Detailed studies of the composition and origin of these ions have been made by high resolution mass spectrometry and analysis of metastable ions. In addition, a large number of isotopically (deuterium and 18O) substituted C-4-alkylated analogues have been prepared to assist in the interpretation of the spectra. The combined results indicate the occurrence of a number of very complex and unusual electron ionization induced fragmentations. Most notable of the findings reported herein concerns the demonstration of the formation of an ion involving loss of the elements of ring A with an intramolecular shift of the oxygen and hydrogen atoms of the hydroxyl function to the charge-retaining species.


Left anterior and left posterior hemiblock in tricuspid atresia and transposition of the great vessels: observations and electrocardiographic nomenclature and electrophysiologic mechanisms. A patient with tricuspid atresia and characteristic electrocardiographic features of counterclockwise and superiorly oriented frontal plane QRS loop (left anterior hemiblock) is presented. Operative intervention resulted in a clockwise and inferior rotation of the frontal QRS loop (left posterior hemiblock) without the development of complete left bundle branch block. This observation suggests that the electrocardiographic pattern of left anterior hemiblock may result from other mechanisms in addition to block of the left bundle branch fibers oriented toward the anterior part of the left ventricle. The case further suggests that electrocardiographic patterns of apparent A-V conduction defects may not be at all associated with true block in the A-V conduction system. Further, it emphasizes the fact that various electrophysiologic mechanisms may account for identical electrocardiographic patterns.


Cognitive-perceptual treatment of exceptional children. Adopting the notion that cognitive operations consist of multiple stages of information-processing, this treatment is designed to specify the locus and nature of the child's deficits in information processing and to compensate for these deficits. Our own clinical and empirical observations, as well as the findings of others, have convinced us that this treatment programme can be applied to exceptional children of many different diagnoses, including emotionally disturbed, learning disabled, autistic, and mentally retarded. A case study involving a seven-year-old autistic child is presented to illustrate the technique, process, and effectiveness of the treatment programme.


Behaviour modification: toilet-training procedures in a special care unit. The design and implementation of a behaviour modification programme for toilet-training is outlined. Two of nine subjects were successfully trained. The results are discussed briefly.


Reduced cholinergic sinus node restraint in hyperthyroidism. The role of the cholinergic nervous system in the tachycardia of hyperthyroidism was investigated in this study of dogs made severely thyrotoxic by the administration of Na-L-thyroxine over a six to nine month period. Differences in heart rate between control and thyrotoxic unanesthetized dogs could be abolished by cumulative doses of intravenous atropine both before and after beta-adrenergic blockade with propranolol, and at submaximal as well as maximal heart rates. There were no differences in the heart rate response of control and thyrotoxic anesthetized dogs to vagal stimulation or to the selective injection of hypertonic saline or acetylcholine into the perfused sinus node artery. The results indicate that in addition to the direct effects of thyroid hormone on sinus node automaticity there is an abnormality in parasympathetic control of heart rate in hyperthyroidism. The data suggest that this abnormality is not due to a decreased responsiveness of the sinus node or an impaired release of the cholinergic neurotransmitter, but may reflect a reduction in cholinergic efferent activity in the thyrotoxic state.


Angiographic findigs and prognostic indicators in patients resuscitated from sudden cardiac death. Sixty-four patients with coronary artery disease (CAD) who had been resuscitated from out-of-hospital ventricular fibrillation (VF) underwent cardiac catheterization and angiography. The majority (72%) had a previous history of cardiovascular disease; in the remaining 28%, VF was the first manifestation of CAD. Advanced coronary atherosclerosis was a common finding; 94% of the patients had severe stenoses (70% or greater diameter narrowing) in one or more of the major coronary arteries, and most (70%) had ventricular wall contraction abnormalities. In over half of the patients, coronary anatomy was potentially suitable for complete revascularization. During an average follow-up period of 20.4 months, fourteen of the 64 patients developed a second episode of VF and/or died suddenly (VF/SD). In an attempt to identify characteristics which might be of prognostic value, the clinical, hemodynamic, and angiographic characteristics of this group were compared to those patients who had a single episode of VF and survived during follow-up. Patients who developed recurrent VF/SD had more triple vessel CAD (P less than 0.01), lower ejection fractions (P less than 0.05), and far more severe abnormalities of left ventricular contraction (P less than 0.001). These results indicate that angiographic findings can identify individuals at high risk for recurrent VF and also suggest that myocardial scarring may be an important factor in the initiation of ventricular fibrillation and in its recurrence.


Drugs in use in schools for severely subnormal children. This paper provides a review of the drug therapy used in the management of the severely subnormal child at school following the introduction of the 1970 Education Act.


The expression of normal ventricular repolarization in the body surface distribution of T potentials. Isopotential maps from 120 normal subjects were obtained from 192 simultaneously recorded electrocardiographic leads. Maps were plotted at 1 msec intervals during the QRS and 5 msec intervals during the ST-T deflection. Repetition of QRS features was evident during all but the first few msec of the initial half of serial T maps. This suggests similarities of the normal sequence of ventricular excitation and recovery. Such similarities have been demonstrated by direct studies but are not evident from other electrocardiographic examinations. Serial maps during later portions of the T wave showed decreasing intensity of potentials with little change of body surface locations. This also correlates with an established feature of ventricular repolarization, namely that potential difference boundaries with stable locations are widely distributed during part of that process. Findings suggest isopotential maps show features of ventricular recovery not apparent from less extensive examinations.


A behavioural programme for the modification of encopresis. This paper describes a behaviour modification programme for the treatment of encopresis. The programme, which is carried out by the parents over a relatively short period of time in the home setting, aims to make the child aware of internal cues prior to elimination and to rearrange the contingencies for appropriate use of the toilet. To date, seven of eleven children, both continuous and discontinuous encopretics, have been treated successfully and have remained clean for up to 7 months regardless of other problems in the child and his family. From a relatively detailed analysis of those treated it can be concluded that a behavioural approach is effective with chronic encopretic children, many of whom had been previously treated unsuccessfully by both physical and psychotherapeutic procedures. The failures suggest, firstly that careful assessment of each child and the motivation of the parents is required, so that the standard programme can be modified to suit each individual case. Secondly a maintenance programme must follow the intensive treatment procedure to ensure that parents continue to handle the child consistently.


Some aspects of community child health in an inner urban area. Some aspects of child health within the community are discussed by a doctor working at the clinical level. The community chosen for discussion is an inner urban area with a multiracial population and problems of poor housing and social deprivation. Reasons for attendance at child health clinics are considered. The provision of care for the preschool handicapped child and the child with special needs is examined.


Anterior infarctional changes occurring during mid and late ventricular activation detectable by surface mapping techniques. This is a comparative body surface potential map study of 26 patients with a recent acute anterior myocardial infarction. The mean plus or minus two standard deviations (+/- 2 SD) for the voltage distribution was established at 5 msec intervals throughout the cardiac cycle in 30 normal subjects at each of 142 recording sites. Instances in which a patient's potential distribution fell outside the normal range were analyzed as to location, duration and intensity against the expected time course of ventricular activation. Only four patients had departures from the normal distribution confined to the Q time zone. Twenty patients had not only Q time zone abnormalities, but had areas of both positivity and negativity exceeding +/- 2 SD, which occurred well after 30 msec. Two patients with clearly documented diagnostic Q waves during the first few days of hospitalization had lost these findings by the date of body surface mapping. They did retain, however, departure map findings demonstrating significant abnormalities occurring between 30 and 60 msec after onset of ventricular activation. These changes occurring in the mid and late time zones of the activation sequence are not detectable by conventional electrocardiography or vectorcardiography, yet present a strikingly apparent finding by this technique of analysis and display.


Multilevel atrioventricular block.

Multilevel atrioventricular block. Arrhythmias displaying conduction disturbances consistent with block at more than one level within the atrioventricular conduction system were seen in 36 patients during a two year period in a community hospital. Two levels of block were postulated in each patient; one patient also demonstrated a third level of block. In 24 patients (Type A), there was an integral conduction ratio at the upper level of block. This pattern was most frequently seen in atrial flutter (mean atrial rate 284 +/- 35 beats/min) with 2:1 block at the upper level and Wenckebach at the lower level. Progression to 2:1 block at the lower level resulted in 4:1 block. Twelve patients (Type B) had a nonintegral conduction ratio of their block at the upper level with a mean atrial rate of 162 +/- 62 beats/min. Their conduction patterns consisted of Wenckebach block at the upper level with either integral (2:1) or nonintegral (Wenckebach) block at the lower level. The presence of multilevel block was not related to specific etiological diagnoses, medications, or electrolyte patterns. It is suggested that multilevel block is a common, frequently transient, conduction pattern seen in a variety of clinical conditions. It is readily recognized from a standard electrocardiogram and, of itself, has no short-term detrimental prognostic implications.


Echocardiographic evaluation of the Valsalva Maneuver in healthy subjects and patients with and without heart failure. The Valsalva maneuver was evaluated by echocardiography in three groups: A) 10 normal volunteers, B) 10 patients with no history of heart failure and normal ejection fractions, and C) 10 patients with heart failure and depressed ejection fractions. Groups A and B had a significant fall in left ventricular internal dimensions and calculated stroke volume by end strain which returned rapidly to baseline in recovery without significant overshoot. Arterial pressure showed a signoidal strain pattern with a normal overshoot in early recovery in all group B patients. In group C ventricular dimensions did not diminish during strain; arterial pressures showed a "square wave" pressure elevation during strain without an overshoot in recovery. Echocardiography allows a new approach to evaluate further the left ventricular response to the Valsalva maneuver. Patients with severely depressed ejection fractions, unlike those with normal ventricular function, are unable to alter stroke output in response to acutely increased intrathoracic pressure. A square wave pressure response is a likely consequence of a fixed stroke output during the strain maneuver.


Effects of acute coronary occlusion on the motion and perfusion of the normal and ischemic interventricular septum. To establish the effect of local and remote myocardial ischemia on interventricular septal motion, 27 open-chest dogs were studied using ultrasound and radioactive microspheres. In 14 dogs the left anterior descending coronary artery was ligated. If the ultrasound beam traversed ischemic septum (proximal LAD occlusion), significant (P less than 0.05) declines in systolic septal velocity (26.4 +/- 2.9 to 6.4 +/- 1.8 mm/sec), and excursion (2.6 +/- 0.3 to 0.7 +/- 0.2 mm) occurred, and systolic thickening was reduced. Similar significant changes were seen when the ultrasound beam traversed nonischemic septum adjacent to the ischemic area (distal LAD occlusion). In 13 additional dogs, circumflex coronary ligation produced posterior ischemia. The mean septal velocity for this group increased significantly (21.8 +/- 2.6 to 26.5 +/- 3.3 mm/sec), as did the septal excursion (2.5 +/- 0.2 to 3.1 +/- 0.4 mm). We conclude that acute LAD occlusion causes a reduction in systolic velocity, excursion, and thickening of both the involved ischemic and the adjacent nonischemic septum. When myocardial ischemia was produced in a part of the ventricle remote from the septum, septal velocity and excursion increased.


Detection of left ventricular aneurysms by cross-sectional echocardiography. Real-time cross-sectional echocardiographic studies of the left ventricle were performed in 31 consecutive patients with angiographically proven left ventricular aneurysms (group I). In each of these patients the presence and location of the aneurysm was visualized by the cross-sectional echocardiography. In four patients discrepancy in the extent of the aneurysm was noted due either to failure of the cross-sectional technique to visualize the entire anterior wall of the ventricle (3) or failure of the single plane angiogram to adequately define the lateral extent of the aneurysm (1). Ventricular shape and contraction sequence in patients with aneurysms were compared with similar patterns in 20 patients with normal left ventricles (group II), and 20 patients with ischemic heart disease and localized ventricular dysfunction without aneurysm formation (group III). Other noninvasive methods for detecting aneurysms (including physical examination, chest roentgenography, electrocardiography, and M-mode echocardiography) were also evaluated in the aneurysm group. This report suggests that cross-sectional echocardiography is a useful method for detecting ventricular aneurysms noninvasively.


Echophonocardiographic studies of the contribution of the atrioventricular valves to the first heart sound. The movements of the mitral, tricuspid and aortic valves have been recorded echocardiographically and related to the first heart sound (S1) in patients with various hemodynamic and conduction abnormalities. Closure of the mitral and tricuspid valves has been studied with respect to the corresponding atrioventricular pressure crossover and it is clear that both valves finish closing about 50 msec after pressure crossover. In order to clarify the relative contribution of tricuspid valve closure and aortic root events to the second high frequency component of S1, a new simultaneous dual echophonocardiographic technique was employed. This permitted the simultaneous registration of tricuspid and aortic valve movements and demonstrated that in certain circumstances the second high frequency component of S1, could be attributed to tricuspid closure, aortic root events being excluded from the genesis of this sound. These observations suggest that the two high frequency components of S1 are related to closure of the mitral and tricuspid valves. The results do not however, exclude a contribution to S1 of aortic root events, which may be of lower frequency vibrations.


Subendocardial blood flow in children with congenital aortic stenosis. Subendocardial blood flow may be estimated from the ratio of flow to the subendocardium to myocardial oxygen consumption. The first may be estimated from the diastolic pressure time index (area between aortic and left ventricular (LV) pressure during diastole) and the latter by the tension time index (integral of LV pressure during systolic ejection). Subendocardial flow index (SEFI) averaged 1.27 (0.96-1.78) in 13 children with normal aortic valves. SEFI averaged 0.88 (0.43-1.65) in asymptomatic children with congenital aortic stenosis and was never greater than 0.9 in symptomatic children. Aortic valve area and systolic pressure difference did not correlate well with symptoms. SEFI and aortic valve area increased in 26 of 28 patients after surgery. However, 23 of 28 had varying degrees of aortic regurgitation following valvotomy. Since calculation of SEFI is not affected by aortic regurgitation, it would appear to be a more useful measure of surgical success than aortic valve area.


Pulmonary regurgitation in large atrial shunts without pulmonary hypertension. Seven patients with pulmonary regurgitation (PR), normal pulmonary artery (PA) pressures and large left-to-right atrial shunts are reported. Six had secundum atrial septal defects (ASD) and one had anomalous pulmonary venous drainage. These comprised 4% of 180 patients with atrial shunts and normal PA pressures. Pulmonary regurgitation was diagnosed clinically by mid-frequency diastolic decrescendo murmurs beginning after the pulmonic component of the second heart sound, and diagnoses were confirmed by catheterization. In two patients who had serial preoperative catheterizations over 8 and 16 years, PR progressed in one and was present only on the second study in the other. All patients underwent shunt correction, at which time the pulmonic anulus and artery appeared dilated, but the pulmonic valves were normal and did not require revision. In all patients the PR murmur disappeared after shunt correction alone, and on chest X-ray both PA and overall heart size decreased. Although it is known that pulmonary regurgitation occurs with atrial septal defects and pulmonary hypertension, the present study demonstrates that it also occurs with high flow atrial shunts, in which setting it has different implications and is reversible with shunt correction alone.


The effect of left ventricular pressure or volume overload on ventricular dimension in children. Left ventricular volume determination from one or two ventricular dimensions. The effect of pressure or volume overload on the geometry of the left ventricle (LV) was determined in order to examine the feasibility and accuracy of LV volume determinations from one minor axis or two dimensions (one minor axis and the longest length). The longest length (LL) and minor axis (MA) in both the anteroposterior (AP) view and lateral (LAT) view were determined from the LV cine silhouette in patients with normal LV volume and pressure (group 1), LV pressure (LVP) overload group (LVP greater than 140 mm Hg, group 2), and LV volume overload group (LV end-diastolic volume greater than 124% of normal, group 3). The ratio of the MA to the LL, which represents the spherical configuration of the LV, was less than "normal" in group 2, and higher than "normal" in group 3. In all groups the LV was less spherical at end-systole than at end-diastole. Additionally, the (MA)3 had a different relationship to true LV volume (biplane LV volume) in the three groups and from diastole to systole in each group. Left ventricular volume calculation from one minor axis was associated with a large error. In contrast, left ventricular volume can be accurately determined from two ventricular dimensions using either the anteroposterior or lateral ventricular image (r larger than or equal to 0.97).


Assessment of left ventricular function in severe aortic regurgitation. Echocardiographic (echo) measurements of left ventricular ejection phase indices--ejection fraction, percent shortening of the minor diameter (%deltaD), and velocity of circumferential fiber shortening (Vcf)--are said to be accurate reflections of their angiographic (angio) counterparts. Most studies correlating echo and angio left ventricular function parameters have included relatively few patients with aortic regurgitation. Echo and angio measurements of left ventricular ejection phase indices thus might not correlate in these patients in whom left ventricular geometry may have been altered due to the volume overload. To test this hypothesis, left ventricular ejection phase indices were determined by angiography and echocardiography and compared in 20 patients with isolated, symptomatic, severe aortic regurgitation. Ejection fraction, %deltaD, and Vcf by LAO cineangiograms and echo were uniformly higher than corresponding measurements from RAO angio, and were often normal in the presence of other indicators of significant left ventricular dysfunction. We conclude that the usual, linear echocardiographic measurement of left ventricular wall motion may not reflect significant myocardial dysfunction in patients with severe aortic regurgitation.


Myocsrdial uptake of technetium-99m stannous pyrophosphate following direct current transthoracic countershock. The effect of direct current (DC) countershock upon myocardial technetium-99m stannous pyrophosphate (PYP) uptake was studied in 22 dogs. All eight dogs imaged had positive abnormal PYP scintigrams that were usually indistinguishable from experimental infarction. In three animals, additional areas of radionuclide uptake were seen in overlying noncardiac tissue. Left and right ventricular myocardial PYP uptake averaged (+/- SEM) 23 +/- 5 times control and 24 +/- 6 times control, respectively. These activity ratios occurred without reduction in regional myocardial blood flow (RMBF), and were associated with histologic evidence of necrosis. The necrosis was usually epicardial, corresponding to the transmural site of greatest PYP uptake. The magnitude of PYP accumulation and the weight of damaged tissue increased with increasing applied energy. Thus, PYP uptake following DC countershock could result in false-positive interpretation of acute ischemic myocardial infarction. Since RMBF is normal in regions of PYP uptake, the major determinant of radionuclide accumulation is the extent of cellular damage.


The relationship of education to blood pressure: findings on 40,000 employed Chicagoans. The relationship of education to both actual blood pressure and the prevalence of high blood pressure, based on a systolic pressure of 160 mm Hg or greater or a diastolic pressure of 95 mm Hg or greater, was analyzed among 27,033 men and women, white and black, age 25-44 and 45-64, from the Chicago Heart Association Detection Project in Industry. The educational status of each individual was categorized as not a high school graduate, high school graduate, some college, or college graduate. A statistically significant inverse association between education and high blood pressure was present in all groups of whites. This association could not be "accounted for" by differences in age, relative weight, and heart rate among the educational strata. Controlling for these variables did, however, lessen the association. Among black males a significant inverse association between education level and blood pressure was found for the younger group. For the older black males there was a clear inverse association although with the small numbers it did not achieve statistical significance. For black females there was no clear association.


Blood pressure in tenth-grade students: results from the Chicago Heart Association Pediatric Heart Screening Project. This report is based on 13,231 tenth-grade students who participated in the Chicago Heart Association Pediatric Heart Screening Project. The blood pressures of these fifteen and sixteen-year-olds were analyzed with respect to sex, race, adiposity, pulse rate, and father's educational attainment. The mean systolic blood pressure was higher in boys than girls by nearly 5 mm Hg, but mean diastolic blood pressure was lower by less than 1 mm Hg. Black tenth-graders had higher mean diastolic blood pressure than whites; the difference in systolic blood pressure was not statistically significant. Adiposity and resting pulse rate were positively correlated with systolic blood pressure and, to a lesser degree, with diastolic blood pressure. After taking adiposity and pulse rate into account, father's educational attainment had a small but statistically significant negative association with diastolic blood pressure in white but not in black students. Nearly 5 percent of students were recalled for a second test because the initial screening blood pressures equaled or exceeded 150 mm Hg systolic or 90 mm Hg diastolic, and almost half of students at the recall examination continued to have pressures of 145/85 or greater.


Postcardiotomy low cardiac output clinical experience with a left heart assist device. Fifteen patients with advanced heart disease who could not be withdrawn from cardiopulmonary bypass (CPBP) because of low cardiac output were supported with a left heart assist device (LHAD). The system (left atrium to ascending aorta bypass of left ventricle) was not employed until all other measures had failed to allow separation from CPBP, including intraaortic balloon counterpulsation whenever possible. In this experience no attempt was made to totally bypass the left ventricle (LV). Rather, LHAD flow rate was adjusted so that the combined output of the LHAD and depressed LV achieved satisfactory levels of systemic blood flow at acceptable LV filling pressures. With improved cardiac performance patients were separated from the LHAD without need for thoracic reentry. Of the 15 patients having LHAD support (longest 21 days), 10 could be separated from the device and six were dismissed from the hospital. Four remain well, the longest 1.6 years postoperatively. Patients requiring 3 days or less of circulatory assistance had a more favorable prognosis than those needing more extended periods of support.


Improved myocardial performance after aortic cross clamping by combining pharmacologic arrest with topical hypothermia. In 22 dogs, we compared the protective effects of combining topical hypothermia and cardioplegia to those of either technique alone on myocardial flow, distribution, metabolism, compliance, and performance after 1 hour of aortic cross clamping. Topical hypothermia alone caused redistribution of coronary flow away from the subendocardium (endocardial/epicardial flow fell from 1.13 to 0.77) and reduced left ventricular compliance and performance severely (48% depression of ventricular function). Cardioplegia alone caused redistribution of flow toward the subendocardium (endocardial/epicardial flow increased to 1.4) and decreased compliance and function moderately (31% depression). In contrast, combined topical hypothermia and cardioplegia caused no significant change in left ventricular flow distribution, compliance, or performance. We concluded that the normal heart can be cross clamped safely for up to 60 minutes (no myocardial depression) only when cardioplegia and topical hypothermia are used in combination (P less than 0.01).


Surgical treatment of aneurysms of the ascending aorta. From January 1970 to April 1975, 132 patients underwent surgical repair of aneurysms of the ascending aorta at this institution, 24 of whom had acute dissections. In almost all cases the ascending aorta was replaced with a Dacron tube graft. Aortic valve replacement was performed in 100 patients and 23 patients underwent coronary artery revision or bypass. Fifteen hospital deaths occurred. Although chronic or nondissecting aneurysms may be dealt with on an elective basis, acute dissections require prompt surgical intervention. Symptomatology and radiographic findings are such that angiography may not be necessary to establish the diagnosis. Clinical evidence of aortic regurgitation in an acute dissecting aneurysm is sufficient indication for immediate operation. Improvements in surgical techniques, fabric grafts, and valve prostheses have all contributed to the successful surgical treatment of aneurysms of the ascending aorta.


Pulmonary artery banding for truncus arteriosus in the first year of life. Results of pulmonary artery banding (PAB) for truncus arteriosus (TA) in infancy are reviewed in 15 children between 1957 and 1974. There were ten hospital and one late deaths (73%). A policy of early correction of severely symptomatic infants with TA was adopted in 1974. Since October, 1974, four infants with TA and one with hemitruncus had a complete correction. Three of these are surviving 22, 17, and 9 months after the operation. Their weight at operation was 4.7, 6.0, and 3.5 kg.


Perioperative myocardial infarction diagnosed by technetium 99m stannous pyrophosphate myocardial scintigrams. Two groups of patients have been studied using 99mTc stannous pyrophosphate myocardial imaging prior to and 3-5 days after myocardial revascularization. The first group consisted of 48 patients undergoing revascularization, including 26 with unstable angina and seven with concomitant valve replacement. There were 3 deaths (6%), and the incidence of perioperative infarction by electrocardiogram (ECG) and enzyme analysis was 6/48 (12%), while 15 of 48 (31%) had positive myocardial scintigrams. The second group of 29 patients included one nonischemic death (3%) that was excluded. The operative technique was changed (optical magnification used, silastic tapes avoided, venting avoided, while aortic cross clamping was used frequently). In this latter group two of 29 (7%) had ECG evidence of infarction while four of 28 (14%) had positive scintigrams, compared to the pervious incidence of 31%. The imaging technique is simple, reliable, and probably more sensitive in the postoperative setting than ECG and enzyme analysis. It appears useful in evaluating the influence of changes in operative technique on myocardial preservation.


Pulmonary atresia: surgical considerations and results in 103 patients undergoing definitive repair. Surgical considerations and results of repair of 103 patients with pulmonary atresia are reviewed. The operative mortality was 10%, related primarily to inability to relieve right ventricular hypertension and to low cardiac output after complex repairs involving significant associated anomalies. In a follow-up study ranging from 6 months to 8 years, there were four late deaths, each being a result of persistent right ventricular hypertension. All but one of the surviving patients are in Class I or Class II. Since operative and late mortality and morbidity are related to unrelieved right ventricular hypertension due to restricted pulmonary arterial outflow, it should be possible to improve results by performance of a preliminary systemic-pulmonary arterial shunt for patients with hypoplastic pulmonary arteries and by correction of patients with large systemic-pulmonary arterial shunts before the development of pulmonary vascular obstructive disease. The striking relief of cyanosis, exercise intolerance, and other symptoms, and the generally favorable operative risk, justify the continued application of surgical correction of pulmonary atresia.


Hemodynamic effects of nitroprusside infusion during coronary artery operation in man. The hemodynamic response to vasodilator therapy with sodium nitroprusside has been assessed in 33 patients with severe coronary artery disease (CAD) during coronary artery operation. The patients were divided into three groups; Group 1 included seven patients with CAD and normal left ventricular filling pressure (LVFP less than 12 mm Hg); Group 2 included 18 patients with CAD and chronic left ventricular (LV) dysfunction (LVFP greater than 12 mm Hg) and Group 3 included eight patients with CAD and acute LV dysfunction (LVFP greater than 12 mm Hg) associated with an intraoperative hypertensive episode. Nitroprusside was administered intraoperatively at an initial infusion rate of 10-15 mcg/min and the rate was gradually increased thereafter until the criteria for effective therapy were satisfied. The effective dose ranged from 10-120 mcg/min with an average of 52 +/- 4 (SEM) mcg/min. In all three groups, pulmonary and systemic arterial pressure, right and left ventricular filling pressure, and pulmonary and systemic vascular resistance decreased significantly with nitroprusside infusion. Heart rate increased significantly in Group 1 and remained unchanged in Group 2 and 3. Heart rate X systolic arterial pressure decreased significantly in Group 1 and 3 and did not change in Group 2. Stroke index increased significantly in both groups of patients with elevated control LVFP (Group 2 and 3) and remained unchanged in patients with normal left ventricular function (Group 1). Left ventricular stroke work index decreased in Group 1, increased in Group 2, and remained unchanged in Group 3. Right ventricular stroke work index decreased significantly in all groups. These findings suggest that judicious intraoperative administration of sodium nitroprusside improves left ventricular function in patients with acute or chronic elevation of LVFP and LV dysfunction associated with severe CAD. Furthermore, nitroprusside is an effective drug for control of intraoperative hypertensive episodes in such patients.


Mitral valve replacement: a 10-year follow-up of non-cloth-covered vs. cloth-covered caged-ball prostheses. The timing of operation and the selection of prosthesis depend upon the evaluation of long-term results at 5 years and beyond. From 1965 to 1975, 290 patients had isolated mitral valve replacement with currently used prostheses, resulting in a 6.6% operative mortality and 64% relative survival at 10 years. In considering mortality, the results obtained with both series of valves were combined and a search made for significant differences in preoperative variables between the operative deaths and operative survivors. The significant variables for operative mortality were valve model, preoperative functional class, pump time, and the presence or absence of right ventricular hypertrophy on electrocardiography. There were significant differences in long-term survival only with regard to preoperative functional class, pulmonary vascular resistance, and pump time. Exponential curves were fitted to the event-free rates, and long-term results were then extrapolated. The 10-year projection of the percentage of patients alive and free of embolus (disregarding transient ischemic attacks) for the Model 6310-6320 (50%) was similar to that actually observed for the Model 6120 (46%). Although further experience may show one prosthesis more effective than the other, statistical extrapolations suggest continued comparable performance.


Use of a valved conduit from right atrium to pulmonary artery for "correction" of single ventricle. Nine patients with single ventricle and pulmonary stenosis were treated by using a valved conduit from right atrium to the main pulmonary artery. The patient's own mobilized pulmonary valve was used in one patient and fresh, adult-sized aortic homograft in the remaining eight. Two additional unstented homografts were inserted at the entrance of both superior and inferior venae cavae in four patients. A pericardial baffle was used to direct pulmonary venous blood to both atrioventricular valves in three, and the tricuspid valve was oversewn in six. L-transposition of the great arteries was present in five patients and D-transposition in one. Tricuspid valve hypoplasia was present in one and mitral hypoplasia in one. The age at operation was 4 months to 36 years. All patients were severely incapacitated with arterial oxygen saturation varying from 28% to 76%. Four patients died within the first week after operation, the remaining five patients derived excellent symptomatic improvement. Repeat cardiac catheterization, performed in five patients, showed a mean right atrial pressure varying from 8 to 17 mm Hg and a prominent right atrial A wave, measuring 10 to 25 mm Hg, with evidence of good function of the homografts at the entrance of the venae cavae. The arterial oxygen saturation varied from 88% to 97%.


Continuous detection of microemboli during cardiopulmonary bypass in animals and man. A device that continuously and accurately detects solid and gaseous microemboli (75-100 muM) during cardiopulmonary bypass is described. A continuous ultrasonic standingwave field was generated between two parallel piezoelectric crystals. Extremely high sensitivity to small changes in ultrasonic attenuation was achieved with a transmission oscillator ultrasonic spectrometer (TOUS). The device was relatively insensitive to variations in flow rate, gradual temperature changes, hematocrit, protein content, and pressure. The system was tested with 100, 200, and 300 muM microspheres. Animal perfusions demonstrated high initial counts that were markedly reduced by an arterial line filter. Furthermore, high cardiotomy suction rates, use of nitrogen, and physical disturbances of the oxygenator increased the microemboli rate. Of 30 clinical perfusions, 15 had complete data for analysis. There was a statistically significant difference (P less than 0.01) in the total number of microemboli between the first 10 minutes (4398 +/- 1132) versus the second 10 minutes of perfusion (2739 +/- 1195). It is concluded that an accurate device that continuously measures the number of microemboli may provide data that will lead to significant improvements in the quality of extracorporeal circulation in the future.