Clonal segregation of oligodendrocytes and astrocytes during in vitro differentiation of glial progenitor cells. To study the clonal lineage of the glial progenitor population, isolated from newborn rat brain (Lubetzki et al. J Neurochem 56:671, 1991), we combined somatic transgenesis using a retroviral vector encoding a modified bacterial beta-galactosidase with nuclear localization, and triple immunofluorescence labeling with A2B5, anti-galactosylceramide, and anti-glial acidic fibrillary protein antibodies. This allowed clonal analysis of the postnatal glial lineage with precise phenotypic identification of each cell within the lacZ-positive clones. When infected cells were cultivated under constant conditions, in the presence of either 1% or 10% fetal calf serum (FCS)-containing medium, all the 250 lacZ-positive clusters examined were homogeneous, i.e., either oligodendroglial or astroglial. Mixed astrocyte-oligodendroglial clones were observed when cells cultivated in the presence of 1% FCS were switched to a 10% FCS-containing medium, confirming the bipotentiality of glial progenitor cells (Temple and Raff Nature 313:223, 1985). However, even under the switch culture conditions, segregation into homogeneous clones of either oligodendrocytes or astrocytes still predominated, and the percentage of mixed clones dropped from 25 to 8 or to 3, when the switch took place at 8, 16, or 22 days in vitro, respectively. Two additional observations lead us to suggest that microenvironmental factors are responsible for the clonal segregation of glial progenitor cells: 1) the uneven distribution of oligodendrocyte and astrocyte clusters, the latter being seen mostly on the edge of the coverslips; and 2) the presence, in the vicinity of an homogeneous lacZ-positive clone, of some lacZ-negative cells expressing the same phenotype.


PDGF increases the expression of Fos and Jun in newly formed oligodendrocytes that have become resistant to the mitogenic effect of PDGF. Bipotential glial (O-2A) progenitor cells give rise to oligodendrocytes on a predictable schedule in the developing rat optic nerve. The loss of mitotic responsiveness to platelet-derived growth factor (PDGF) that is seen when O-2A progenitor cells initially differentiate into oligodendrocytes seems to reflect blocks or deficiencies downstream to some of the early intracellular signalling events induced by PDGF. Here we show that PDGF increases the expression of the Fos and Jun nuclear proteins in newly formed oligodendrocytes in vitro, suggesting that at least one intracellular signalling pathway to the nucleus is activated by PDGF in these cells even though they do not synthesize DNA in response to PDGF.


Mycotic keratitis: a study in coastal Karnataka. Fungi were isolated from 67 cases out of the 295 cases of corneal ulcers investigated. Aspergillus species and species of Candida were the major fungal members isolated. Allescheria boydii was isolated from 3 cases, having no previous history of injury to the eye or infection with bacterial or viral agents. A boydii corneal infection is a rare occurrence. Higher incidence of mystic keratitis was seen among females than males. No relationship to seasonal changes could be established. Bacterial infection was associated in 46. 27% of the cases of mycotic keratitis and Staphylococcus was the predominant bacterial pathogen observed.


5'-Nucleotidase immunoreactivity of perineuronal microglia responding to rat facial nerve axotomy. The ecto-enzyme 5'-nucleotidase was localized immunocytochemically in the axotomized rat facial nucleus. As revealed by the monoclonal antibody 5N4-2,5'-nucleotidase immunoreactivity markedly increased on perineuronal microglia during the first week following axotomy, and gradually disappeared from these cells by the end of the third post-operative week. Interestingly, parenchymal microglia were not or only weakly stained. These findings indicate that 5'-nucleotidase 5N4-2-immunoreactivity may serve as a marker for perineuronal microglia, a population of satellite glial cells that appear to be actively engaged in lesion-induced synaptic changes during regeneration.


Interleukin 2 and interferon alpha modulation of the lymphocyte non-major histocompatibility-restricted lytic activity in glioblastoma patients. We studied the non-major histocompatibility-restricted cytotoxic activity induced by interleukin 2 (IL-2) and interferon alpha (IFN-alpha) in mononuclear cells of peripheral blood (PBMNC) from glioblastoma patients. We observed a depressed cytotoxic activity against natural killer (NK)-sensitive target cells in PBMNC from all the patients studied. Culture of these PBMNC with IFN-alpha for 5 days augmented the cytotoxic activity against NK-sensitive target cells in a small group of patients. Incubation with IL-2 for 5 days normalizes the decreased cytotoxic activity against NK-sensitive target cells of PBMNC from all the glioblastoma patients studied. When PBMNC from these patients were incubated with IL-2 for 5 days and IFN-alpha was added to the culture medium in the last 2 h of culture, an enhancement of non-major histocompatibility-restricted cytotoxic activity was observed compared with that obtained with either IL-2 or IFN-alpha alone. This improvement of the cytotoxic activity was more relevant when it was tested against NK-resistant target cells. The potential utility of the sequential use of the two cytokines in generating non-major histocompatibility cytotoxic activity in glioblastoma patients is discussed.


Mitogenic and tumor necrosis factor producing activities of Pseudostellaria heterophylla. Separation of mitogenic fraction (PH-I) from Pseudostellaria heterophylla and characterization of its biological activities were investigated. PH-I was isolated as an alcohol-insoluble fraction from the hot water extract obtained by heating the roots of P. heterophylla in water at 80 degrees C for 4 h. It is a water-soluble substance consisting of mainly carbohydrates (56.8%) and a small amount of proteins (7.6%). The incorporation of tritiated thymidine into the DNA of murine spleen lymphocytes could be stimulated by PH-I in a dose-dependent manner. PH-I could act as a priming agent for the release of tumor necrosis factor (TNF) in mice. Moreover, PH-I exhibited potent anti-tumor activities against Ehrlich ascites tumor (EAT) cells in vivo but not in vitro.


Steroid interactions affecting metabolic activities of a T-lymphocyte line. A glucocorticoid sensitive T-lymphocyte cell line (CEM) was used to study in vitro interaction effects of steroidal compounds on their metabolic activity. Mixtures of steroidal hormones and related substances were added to the cells and assessed in short-term culture experiments by the incorporation of 3H dTr. Dose ranges were selected to include the linear portion of the dose-response curve of each of the potentially interactive substances. Evidence for synergy, additivism or antagonism was obtained for each of the various steroid combinations studied using algebraic and geometric calculations.


Effect of tumor burden and route of administration on the immunotherapeutic properties of polyinosinic-polycytidylic acid stabilized with poly-L-lysine in carboxymethyl cellulose [Poly(I,C)-LC]. We examined the immunomodulatory and therapeutic activities of poly(I,C)-LC. Mice received a subcutaneous (s.c.) injection of sufficient numbers of MBL-2 lymphoma cells to produce in 1 week either a high or low tumor burden. A week after tumor cell injection, poly(I,C)-LC treatment was initiated; the agent was administered intraperitoneally (i.p.) at 5 mg/kg twice a week or at 2.5 or 0.5 mg/kg every day or as an intravenous (i.v.) injection at 0.5, 0.05, or 0.005 mg/kg three times a week. Poly(I,C)-LC treatment significantly increased antitumor effector cell functions in a variety of organs (including spleen, lungs, and peritoneum), as shown by increased killing of MBL-2 cells in vitro and increased tumor cell killing by natural killer cells and macrophages. Furthermore, prolongation of survival correlated with peritoneal macrophage tumoricidal activity when poly(I,C)-LC was given i.p. and with pulmonary effector cell function (including natural killer, cytolytic T-lymphocyte and macrophage tumoricidal activity) when the agent was administered i.v.


Endogenous production of tumor necrosis factor in normal mice orally treated with Deodan--a preparation from Lactobacillus bulgaricus "LB51". The ability of orally administered Deodan, a product from the cell wall of Lactobacillus bulgaricus strain "I. Bogdanov patent strain tumoronecroticance B51" ATCC #21815, shortly called "LB51", to induce endogenous tumor necrosis factor-alpha (TNF alpha) production in normal mice was evaluated. The priming and triggering activities of the preparation were investigated in combination with lipopolysaccharide (LPS) and live BCG vaccine. Deodan was applied at a dose of 150 mg/kg and various treatment schedules were employed. The serum levels of TNF alpha in treated mice were quantified by ELISA. Oral administration of Deodan at a dose of 150 mg/kg for 1, 3, 10 or 20 consecutive days only enhanced serum TNF alpha levels in treated mice. Maximal TNF alpha levels were reached 6 h after the last application of Deodan. Deodan was effective in priming TNF alpha in mice triggered intravenously (i.v.) with LPS. Deodan triggered the production of TNF alpha in BCG-primed mice. The preparation, however, was not an effective trigger of mice primed intradermally (i.d.) with 1 microgram/mouse LPS. These findings suggest that Deodan is both a primer and trigger of endogenous TNF alpha. The advantages of treatment of neoplastic disease with agents which induce endogenous TNF alpha is discussed.


In vivo enhancement of murine natural killer cell activity by 7-allyl-8-oxoguanosine (loxoribine). 7-Allyl-8-oxoguanosine (loxoribine) is a novel immunostimulatory compound which has been shown previously to enhance the antibody synthesis of antigen-stimulated B-lymphocytes. In this report, loxoribine was tested for the ability to activate murine natural killer (NK) cells. In studies in which mice were given a single subcutaneous (s.c.) or intravenous (i.v.) injection of loxoribine, splenic NK cell activity was increased in a dose-related manner with clear enhancement seen within 2 h of drug administration. The enhancement was optimal at 48 h but persisted for a minimum of 4 days. Slow and continuous administration of loxoribine via subcutaneously implanted infusion pumps successfully enhanced the NK activity for several days after all of the pump contents had been delivered. Peak NK responses were seen following s.c. or i.v. administration of 2-3 mg loxoribine per mouse in sesame oil, intralipid, or saline vehicles. Significant oral activity was seen after the administration of 8-10 mg/mouse in sesame oil or intralipid. The in vivo enhancement of NK activity was observed in spleen, blood, and bone marrow but was negligible in lymph nodes and thymus. Multiple injections of optimal concentrations of loxoribine did not tend to enhance the NK activity above that seen with a single injection, suggesting that the timing of injections was critical for optimal responsiveness.


Effect of Ebselen on polymorphonuclear leukocyte adhesion to and migration through cytokine-activated vascular endothelium. Ebselen (PZ51, 2-Phenyl-1, 2-Benzoisoselenazol-3-(2H)-one) is a selinyl organic compound with anti-inflammatory properties. Some of its pharmacological effects are thought to result from its peroxidase activity. Here we examined the effects of Ebselen on polymorphonuclear leukocyte (PMNL) adhesion to umbilical vein endothelium and transendothelial migration in a modified Boyden chamber in which both PMNL-dependent and endothelial-dependent (IL-1, TNF alpha) PMNL adhesion and migration can be measured. Ebselen was found to dose dependently inhibit the adhesion of PMNL to IL-1 activated endothelium and to inhibit transendothelial PMNL migration induced by IL-1 alpha, and TNF alpha with an IC50 value of 28 microM. Transendothelial migration induced by the PMNL chemotactic agents C5adesArg and N-formyl-norleu-leu-phe was also inhibited at slightly higher concentrations. The effect of Ebselen was not on endothelial cell activation but on PMNL activation for adhesion and migration. This effect on PMNL was irreversible for the duration of the assay period (75 min). The results suggest that the anti-inflammatory activity of Ebselen may, in part, be due to direct inhibition of PMNL adhesion to vascular endothelium and transendothelial migration in response to a variety of inflammatory mediators.


Mitogenic activity of (-)epigallocatechin gallate on B-cells and investigation of its structure-function relationship. (-)Epigallocatechin gallate (EGCg), the main constituent of green tea, strongly enhanced the direct plaque-forming cell (PFC) response to sheep red blood cells (SRBC) in vitro and showed strong mitogenic activity for mouse splenic B-cells but not for splenic T-cells and thymocytes. The enhancement of B-cell proliferation was not mediated by macrophages since their removal did not eliminate the activity. Among the derivatives of catechin examined, (+)catechin (C); (-)epicatechin (EC); (-)-epigallocatechin (EGC); (-)epicatechin gallate (ECg); (-)epigallocatechin gallate (EGCg); and theaflavin digallate (TF3), only the derivatives with the galloyl group (ECg, EGCg, and TF3) displayed significant enhancement of the spontaneous proliferation of B-cells. Structural analogs of the catechin and galloyl groups were also examined in the system. Gallic acid and tannic acid induced some enhancement, but rutin, pyrogallol and caffeine did not. The results indicate that the galloyl group on EGCg was responsible for enhancement. However, the basic conformations of the catechins are also important, because ECg, EGCg, TF3, gallic acid, and tannic acid had quite different potencies to induce B-cell proliferation.


Reconstruction of anti-leprosy drug depleted complement haemolytic activity by addition of zymosan-treated sera (a source of C142) and CratEDTA (a source of C3-C9). This paper describes the mechanism of in vitro interaction of human serum complement system with anti-leprosy drugs (dapsone and clofazimine) and anti-lepra reaction drugs such as chloroquine. These drugs could inhibit the complement-mediated lysis of erythrocytes both via direct and alternative pathways, but only at hypertherapeutic doses. Attempts were made to restore the drug depleted complement-mediated lysis of erythrocytes by adding zymosan-treated guinea-pig sera (a source of C142) and also by adding Crat-EDTA sera (a source of C3-C9). Destroyed complement-mediated haemolytic activity by dapsone could be restored by early complement (C142) components, while complement-mediated haemolytic activity blocked by clofazimine could be regenerated by adding both late (C3-C9) and early (C142) complement component. However, chloroquine-mediated inhibition of the complement-mediated haemolysis activity could not be appreciably restored by adding both early and late complement reagents.


Combined effects of synthetic lipid A analogs or bacterial lipopolysaccharide with glucosaminylmuramyl dipeptide on antitumor activity against Meth A fibrosarcoma in mice. The combined effects of the synthetic glucosaminylmuramyl dipeptide (GMDP) on the antitumor activity of chemically synthesized lipid A analogs, compound A-103 (glucosamine-4-phosphate with (R)-3-tetradecanoyloxytetradecanoyl group at the C-2 and C-3 positions), Escherichia coli-type lipid A (506), Salmonella typhimurium LT-2 lipopolysaccharide (LPS) against Meth A fibrosarcoma in mice were examined. Meth A fibrosarcoma cells (5 x 10(5) were inoculated intradermally into BALB/c mice on day 0, and compound A-103 and/or GMDP was administered intravenously (i.v.) on days 7 and 9. Two i.v. injections of A-103 (50 micrograms) alone or GMDP (10 micrograms) alone induced 42.8 or 51.8% inhibition of the rate of tumor growth, however, A-103 (100 micrograms) with GMDP (10 micrograms) exhibited a high 68.7% inhibition rate 19 days after tumor inoculation. The inhibition of the tumor growth rate by the combination A-103 (100 micrograms) or 506 (50 micrograms) with GMDP (10 micrograms) was stronger than that of A-103 or 506 with MDP (10 micrograms). The combination of LPS (1 or 10 micrograms) with GMDP (10 micrograms) exhibited a higher inhibition rate than that of LPS with MDP, and three or four tumor-free mice out of five mice were observed, suggesting that the combined effect of GMDP is more potent than that of MDP. With the addition of GMDP, A-103 did not enhance the production of tumor necrosis factor (TNF) on the basis of L929 cell lysis.(ABSTRACT TRUNCATED AT 250 WORDS)


Gamma-interferon corrects aberrant protein kinase C levels and immunosuppression in the spontaneously hypertensive rat. The effects of gamma-interferon (gamma-IFN) on protein kinase C (PKC) levels and immunosuppression in the spontaneously hypertensive rat (SHR) were examined. First, an abnormal PKC distribution was found in spleen, thymus and aorta from SHRs relative to normotensive controls. Biweekly injections of rat recombinant gamma-IFN (1000 U/kg) restored basal or resting PKC levels to those found in normotensive Wistar-Kyoto (WKY) rats. We also examined the effects of in vivo gamma-IFN treatment on nuclear PKC (nPKC) activation in purified, isolated splenocyte nuclei. It was found that basal nPKC levels were higher in untreated SHRs than gamma-IFN SHRs or WKYs. Also, while nuclei from untreated SHRs were relatively unresponsive to various immunoreactive substances and PKC activators, gamma-IFN treatment significantly restored activity. Last, the proliferative response to mitogen challenge of isolated splenocytes from untreated SHRs, gamma-IFN-treated SHRs and WKYs was studied. Although gamma-IFN treatment did not restore the proliferative response to that of WKYs, the mitogen response was significantly enhanced by treatment with gamma-IFN. The data show that gamma-IFN acts to restore normal immune function and corrects aberrant PKC levels and adds to the growing body of knowledge suggesting a role for immune dysfunction in the etiology of hypertension.


Determination of cytokine release after in vivo and in vitro administration of Deodan (a preparation from Lactobacillus bulgaricus "LB51") by the rabbit pyrogen test. We investigated the in vivo and in vitro cytokine inducing effects of Deodan, an oral preparation from Lactobacillus bulgaricus "LB-51", using the rabbit pyrogen test. In the first experimental approach we administered Deodan, or its chromatographically purified fraction, via the i.m. or i.v. routes. Low doses of Deodan i.m. caused the formation of a single temperature peak, whereas large doses produced a biphasic temperature curve. Intravenous injection of Deodan produced a monophasic fever in all tested doses. Chromatographically purified Deodan injected i.v. to rabbits caused a febrile response with a dose-dependent pattern, strikingly similar to that of lipopolysaccharide. LAL-testing of Deodan, however, showed that the preparation does not contain endotoxin. In in vivo neutralization studies we demonstrated that IL-1, TNF alpha, and IL-6 mediate the rabbit febrile response to Deodan. Interestingly, the effects of Deodan on the production of TNF alpha and IL-6 were more pronounced than its IL-1 inducing activity. In the second approach, we injected supernatants from mononuclear cells incubated with nonpyrogenic doses of Deodan, intravenously to rabbits ("monocyte type" of pyrogen test). Rapid-onset monophasic fevers were observed, typical for the rabbit pyrogen reaction to i.v. administration of exogenous IL-1 and TNF. Finally, we demonstrated the presence of pyrogenic cytokines in the supernatants from macrophages of Deodan-treated mice. Together, these results indicate that Deodan induces the production of cytokines with endogenous pyrogenic activity.


Activation of spleen cell lytic activity by the alkaloid thiophosphoric acid derivative: Ukrain. Ukrain is a semisynthetic compound consisting of alkaloids from Chelidonium majus L. conjugated to thiophosphoric acid, with immunomodulatory and therapeutic properties in cancer patients. The present in vitro studies demonstrate that Ukrain is an effective biological response modifier in that it augmented, by up to 48-fold, the lytic activity of spleen lymphocytes obtained from alloimmunized mice. The lytic activities of IL-2-treated spleen cells and peritoneal exudate lymphocytes were also increased significantly by the addition of Ukrain to the CML assay medium. The highest Ukrain-induced enhancement of spleen lymphocyte lytic activity in vitro was found to occur at 18 days after alloimmunization, was dose dependent and specific for the immunizing P815 tumor cells. Since Ukrain was present only during the CML assays, its mode of action is thought to be via direct activation of the effector cell's lytic mechanism(s).


Development of an orphan drug by a start-up company. MetroGel for rosacea. The Orphan Drug Act of 1983, along with the discovery of a new use for a known drug and an investor willing to assume the necessary risk, brought about the formation of a start-up pharmaceutical company. The primary incentive of the Orphan Drug Act of seven years of marketing exclusivity provided the protection from competition necessary for recovery of the significant research and development and marketing costs. The orphan product, MetroGel, for the treatment of rosacea, required approximately five years of development before it was approved for marketing by the Food and Drug Administration. MetroGel has become the number one drug in the United States for the treatment of rosacea. It currently is marketed in other countries through a licensing agreement with a major pharmaceutical company.


Evolution and current status of the Orphan Drug Act. The 1983 Orphan Drug Act was designed in response to market and regulatory disincentives that limited industrial interest in developing drugs needed by people in the United States with rare diseases and conditions. These disincentives evolved from changes in the pharmaceutical industry and in regulatory testing requirements. In the eight years since the Act and subsequent amendments have been in effect, the law has been associated with the new development and approval of 40 marketed drugs and 12 biologicals to treat rare (orphan) diseases. An additional 281 drugs and 141 biologicals have been entered into development and designated as orphans. Finally, the law has mandated exploration of whether the incentives of the Act are necessary and appropriate for stimulating industrial development of orphan medical drugs and devices. Despite this progress, controversies have arisen over three profitable orphan products that have benefited from the law's provisions. This has created the need for continued assessment of the Act's benefits and costs.


Creating the costliest orphan. The Orphan Drug Act in the development of Ceredase. The FDA recently approved Ceredase, a new treatment for Gaucher's disease, under the provisions of the Orphan Drug Act. Ceredase is unusually expensive, but there are no satisfactory alternative therapies. It appears likely that Ceredase would not have become available without the protection of the Orphan Drug Act, but its expense and the lack of information about its long-term effects on health raise questions about whether the ODA provides appropriate incentives to develop cost-effective technologies.


Automated ambulatory medical records systems. An orphan technology. Automated ambulatory medical records systems (AAMRSs) have been operational for over 20 years but have not been adopted by more than a small fraction of their potential users. This paper presents a detailed analysis of the uses and benefits of the COSTAR-based AAMRS at the Harvard Community Health Plan and of the factors which have inhibited the dissemination of COSTAR. We conclude that AAMRSs have been an orphan technology and cite trends in health care that favor the future development of AAMRSs.


Clinical PET scanning. A "short-lived" orphan. Positron emission tomography (PET) is a method of nuclear medicine imaging that uses short-lived radiopharmaceuticals to detect and quantify the metabolic abnormalities of disease processes. PET initially was developed in a research environment as a research tool; data from these research studies resulted in the gradual recognition that PET studies would be useful for various routine clinical applications. The diffusion of PET into clinical practice has been slow in comparison with other new imaging methods (e.g., magnetic resonance imaging). This slow diffusion is attributable to several factors, including the complexity and high cost of PET, the uncertain role of the U.S. Food and Drug Administration in regulating the radiopharmaceuticals that are produced and used on-site for PET studies, and the apparent slow pace at which the Health Care Financing Administration and other third-party payers are developing policies for reimbursing for PET.


Health technologies for the developing world. Addressing the unmet needs. This paper provides a critical overview of several strategies and mechanisms that have been employed by the Program for Appropriate Technology in Health over the past decade to address the unmet needs for health technologies in the developing world. Partnerships between public and private-sector organizations are emphasized in order to share risks, encourage efficiency, and ensure the availability of priority products for health care in resource-poor settings. Incentives for the involvement of the commercial sector, the means to protect the interest of the public sector, and the role of bridging organizations are discussed in the light of the shifting goals of the public sector.


Recombinant erythropoietin. Orphan product with a silver spoon. The U.S. Food and Drug Administration's (FDA) approval to the orphan biological product recombinant erythropoietin (rEPO) in June 1989 resulted both in a breakthrough treatment for the chronic anemia of people who suffer from chronic renal failure and a powerful argument for change in the legislation that spawned its development: the Orphan Drug Act of 1983. At a cost of over $6,000 per patient per year, Congress could not understand how a product that no manufacturer wanted to produce was suddenly costing the federal government hundreds of millions of dollars each year. Congress attempted to change the act in 1990 to preclude a manufacturer from using its provisions to secure lucrative monopolies in certain drug markets. In early 1991, the FDA finally issued regulations to implement the act that addressed some of the very concerns that were caused by rEPO.


Evaluation of orphan products by the U.S. Food and Drug Administration. Orphan drug products generally are used in treating or preventing rare diseases. The small number of patients available for study may create special problems in the evaluation of these products. This paper examines some of the special problems that are associated with the design and implementation of studies to evaluate the safety and efficacy of orphan drugs. The U.S. Food and Drug Administration (FDA) has not established special criteria for evaluating orphan drugs per se, but the FDA has been flexible in evaluating drug products that present special problems, especially when these products are for treatment of serious of life-threatening illnesses. The FDA and other U.S. governmental agencies also have taken steps to promote the development and availability of drugs for rare diseases, including making these products available to patients who are in need, even before the drugs have full FDA marketing approval.


Contraceptives. On their own.

Contraceptives. On their own. Despite the need for more safe and effective contraceptive drugs and devices, enormous barriers to contraceptive research and development have been raised in the United States. The designation of contraceptives as orphan drugs, with concomitant incentives, may be warranted to encourage private manufacturers to reenter the field.


Issues in the cross-national assessment of health technology. With the growing international literature in economic evaluation and the rapid spread of new health technologies, there is a need to undertake, or at least interpret, economic evaluations on the international level. However, the ways in which cross-national differences affect the cost-effectiveness of health technologies or their evaluations have never been studied. This paper explores these issues by taking advantage of a unique situation in which the same economic evaluation of a new indication for a health technology was conducted simultaneously in four countries using an identical methodology. The study showed that if prior agreement on methods can be reached and local data applied, economic evaluations can be undertaken in a way that facilitates the extrapolation of results from country to country.


The Consensus Development Program. Detecting changes in medical practice following a consensus conference on the treatment of prostate cancer. The treatment of prostate cancer was reviewed at a U.S. National Institutes of Health Consensus Development Conference in June 1987. Data from the U.S. National Cancer Institute's Surveillance, Epidemiology, and End Results tumor registries were analyzed and showed that the proportion of eligible prostate cancer patients receiving the recommended therapies did not increase at a faster rate after the conference than before.


Cost-effectiveness of the screening and treatment of diabetic retinopathy. What are the costs of underutilization? Diabetic retinal disease remains a leading cause of visual disability among those of working age. Controlled trials have demonstrated that timely diagnosis and photocoagulation treatment can reduce significantly the likelihood of visual impairment in affected diabetic patients. Using a prospective simulation model, we show that an annual screening and treatment program saves thousands of years of vision and reduces medical expenditures over the lifetime of a cohort of Swedish Type I diabetic patients.


Information dissemination and the cesarean birth rate. The Illinois experience. A study was initiated to investigate the impact of information dissemination in Illinois upon the projected rise in the cesarean birth rate over the period from 1986 through 1988. The total cesarean birth rate in Illinois had not changed significantly during this period, whereas the rate of vaginal births after cesarean sections (VBAC) increased by 58.4% (p < .001). Information dissemination may have contributed to stemming an increase in the cesarean birth rate in Illinois while promoting VBAC deliveries.


A model for evaluating the cost-effectiveness of cholesterol-lowering treatment. We describe and illustrate the use of a generalizable model for evaluating the cost-effectiveness of alternative cholesterol-lowering treatments. We combine standard incidence-based techniques for measuring the cost of illness with logistic risk functions from the Framingham Heart Study to project, for persons with known coronary risk characteristics, the likelihood of developing coronary heart disease (CHD) over a lifetime as well as a number of related outcomes, including the expected loss of years of life due to CHD, the expected lifetime direct and indirect costs of CHD, and the changes in these outcomes that would result from cholesterol-lowering treatment.


X-linked retinitis pigmentosa: functional phenotype of an RP2 genotype. Rod- and cone-mediated function was studied with psychophysics and electroretinography in members of an X-linked retinitis pigmentosa pedigree with the RP2 genotype. An asymptomatic hemizygote with an early stage of the disease had cone dysfunction in the mid-periphery and an abnormal cone electroretinogram (ERG); rod function was normal. Hemizygotes with more advanced disease had cone and rod dysfunction in the mid-peripheral retina and cone dysfunction in the far periphery; cone and rod ERGs were abnormal. At very advanced stages, there was an absolute mid-peripheral scotoma and marked cone and rod dysfunction in the far peripheral and central retina. Cone and rod ERGs were severely abnormal or not detectable. Heterozygotes showed tapetal-like reflexes, patches of pigmentary retinopathy, and a range of functional findings from no detectable abnormalities to moderate levels of retinal dysfunction. There were regions of normal function adjacent to dysfunctional patches that had greater cone than rod sensitivity losses or comparable cone and rod losses. The results suggest that the phenotype of this RP2 genotype of X-linked retinitis pigmentosa, unlike other forms of retinitis pigmentosa, is first expressed as a cone photoreceptor system dysfunction, and as the disease progresses, both rod and cone systems are involved.


Fatty acid composition of the human macula and peripheral retina. The fatty acids in the human retina and the macular region were measured quantitatively (mole percent) by gas chromatography. The major fatty acids of the human retina and macula were palmitic, stearic, oleic, arachidonic, and docosahexaenoic. Surprisingly, there was much less docosahexaenoic acid in the macular region (15.9% of total) than in the peripheral retina (22.3% of total). There was a group of "other fatty acids," not any of the five major fatty acids, that were relatively more abundant in the macula (21.0% of total) than in the peripheral retina (10.7% of total). These results indicate that the human macula has a unique biochemical composition, which differs substantially from the peripheral retina. Establishment of the biochemical composition of the macula may be important for helping recognize possible changes associated with diseases such as age-related macular degeneration.


Region and age-dependent variation in susceptibility of the human retina to lipid peroxidation. Trephined buttons from the posterior central (including the macula) and four peripheral regions of human retina were subjected to in vitro lipid peroxidation initiated by Fe+2. There was an age-related increase in peroxidation in the retinal tissue from the posterior region (P = 0.0019), but not in tissues from any of the four peripheral retinal quadrants (collective P = 0.24). These results suggest that the posterior region of the human retina is susceptible to lipid peroxidation and that age is a factor.


Accurate and precise measurement of blood-retinal barrier breakdown using dynamic Gd-DTPA MRI. Dynamic T1-weighted magnetic resonance imaging (MRI) after the injection of Gd-DTPA is a promising method for investigating breakdown of the blood-retinal barrier (BRB). Previously, the authors demonstrated that in a T1-weighted image, the initial rate of change in the vitreous water MRI signal as gadolinium diethylenetriaminepentaacetic acid (Gd-DTPA) enters the vitreous space strongly correlated with the extent of BRB breakdown. Here, a practical approach to measuring a more relevant physiologic parameter is presented: the permeability surface area product (PS). The theory is a development of earlier work used in investigating the breakdown of the blood-brain barrier. The accuracy and precision of this approach was investigated in rabbits pretreated with sodium iodate (30 mg/kg intravenously). The MRI-derived PS normalized to the area of leaky retina (5.65 +/- 0.25 x 10(-4) cm/min, mean +/- standard error of the mean; n = 6) was compared to a similarly normalized PS calculated using a classical physiologic method (4.12 +/- 0.73 x 10(-4) cm/min; n = 6). Good agreement between the two methods was found (P = 0.09). This result demonstrates that the MRI-derived PS is an accurate and precise measure of BRB breakdown under these conditions. The mathematical model of Gd-DTPA distribution in vivo also is validated. Based on these results, several potential sources of error are discussed, including the effect of back-flow of Gd-DTPA from the vitreous space to the plasma, the underlying vascular patency, and MRI slice selection.


In vivo imaging of breakdown of the inner and outer blood-retinal barriers. Real-time contrast-enhanced magnetic resonance imaging (MRI) was used to distinguish between experimentally induced breakdown of the vascular (inner) and retinal pigment epithelial (RPE; outer) blood-retinal barrier (BRB) in vivo. Pigmented rabbits were treated with intravenous sodium iodate 30 mg/kg, (a specific RPE cell poison), intravitreal N-ethylcarboxamidoadenosine (NECA) 10(-3) mol/l (which specifically disrupts the vascular BRB), or retinal diode laser photocoagulation. Coronal T1-weighted proton images were acquired in a timed sequence after intravenous injection of gadolinium diethylenetriaminepentaacetic acid (Gd-DTPA). Images were analyzed to localize leakage of Gd-DTPA and determine the permeability surface area product normalized per unit area (PS). The pattern of enhancement observed in eyes treated with sodium iodate differed clearly from that in eyes treated with NECA. PS' values were significantly higher in eyes treated with sodium iodate than with NECA. Simultaneous leakage from the outer and inner BRB in eyes treated with dense retinal laser photocoagulation could be localized and quantitated independently.


Flicker perimetry resists retinal image degradation. The influence of refractive defocus and artificial media opacities on perimetric thresholds in automated light-sense and flicker perimetry was investigated in 20 eyes of 20 normal subjects. Thresholds were determined at 13 locations in the central visual field up to 25 degrees. Refractive defocus was induced by blurring with glasses of +1, +2, +3, +6 and +9 diopters spherical. Three diffusers were used as artificial media opacities, causing a mean reduction of visual acuity to 0.46, 0.08, and 0.02. Blurring of the retinal image by a small defocus or by slight artificial media opacities causes a measurable reduction of light-difference sensitivity. Mean sensitivity (MS) and defocus are related logarithmically (log(MS)/defocus, r = -0.9297; P < 0.0001). The correlation between MS and the luminance factor l15, characterizing the artificial media opacities, is linear (MS/l15, r = -0.9736; P < 0.0001). Flicker fusion frequency resists retinal image degradation much better. Mean flicker frequency (MF) and defocus are related logarithmically (log(MF)/defocus, r = -0.4960; P < 0.0001). The correlation between mean flicker frequency (MF) and the luminance factor l15 is nonlinear (MF/[l15]2, r = 0.8693; P < 0.0001). The results of the present study show that perimetric methods that use temporal threshold criteria, such as flicker fusion frequency, should be more suitable than methods that use static criteria for detecting neuronal damage in the presence of factors that disturb retinal image quality.


An improved apparatus for transscleral iontophoresis of gentamicin. The authors previously found that positively charged substances are less well-transported into the vitreous humor by transscleral iontophoresis than are negatively charged substances. There was more bubble formation in the eye cup with positively charged than with negatively charged substances. The authors hypothesized that these bubbles might account for the poorer conductance of the positively charged species by causing interruptions of the current. Therefore, the authors developed a modified eye cup in which the diameter of the fluid column was larger than that in the old device (1.0 rather than 0.5 mm). This modification allowed larger voltage to be applied than with the older device, because bubbles could be more easily cleared from the conjunctiva than with the narrower-bore eye cup. Although the efficiency of the apparatus was the same with the two eye cups (micrograms per milliliter in vitreous humor divided by milliampere minutes of current applied), vitreal concentrations of gentamicin with the modified eye cup were fourfold higher than with the older eye cup (83 versus 19 micrograms/ml; P < 0.001). These studies suggest that modifying the eye cup to permit easier removal of bubbles resulted in improved delivery of gentamicin into the ocular humors.


Acute laser lesion effects on acuity sweep VEPs. Q-switched neodymium-YAG (infrared) laser lesions at energies up to and including retinal hemorrhages were placed under visual control in the parafovea and the fovea of anesthetized monkeys. Visual-evoked potential (VEP) data were obtained by parallel analog (vector voltmeter) techniques from scalp electrodes in response to high luminance counterphasing sine wave gratings. The gratings were swept downward in spatial frequency to determine an acuity estimate by recording of the VEP magnitude increase onset. Acuity estimates were determined immediately post-exposure and at 15 sec intervals up to 12 min. These were analyzed as a function of laser exposure site and retinal lesion produced. Significant delays in VEP lock-in were demonstrated in subjects that had parafoveal burns or parafoveal subretinal hemorrhages. Foveal burns caused severe short-term fluctuations before a sustained decrease in acuity. Contained foveal hemorrhages produced sustained acuity losses. Foveal exposures that did not produce an immediately visible lesion did not produce measurable changes in VEP response lock-in time. These results probably are independent of visible flash effects and indicate that there may be a transient neural shock effect from parafoveal lesions that can affect the fovea.


Age dependence and distribution of green and blue fluorophores in human lens homogenates. This is comprehensive study of the age dependence and regional distribution of the blue and the green fluorophores, per unit protein, (specific fluorescence) in the human lens. Spectroscopic measurements were obtained using fiber optic sensors that considerably improved upon techniques used in the past because inner-filter and scattering effects were minimized. An increase in the specific green and blue fluorescence was observed with increasing age in the soluble and insoluble nuclear fractions. In the cortical fractions, an increase with age was observed in lenses of donors under 30 yr old. No significant variations in the specific fluorescence were measured beyond the third/fourth decade of life in the cortical fractions. The specific fluorescence was about twice as high in samples from the cortex compared to those from the nucleus. The insoluble protein fractions also exhibited twice as much specific fluorescence compared to the soluble ones. At older ages, the fluorescence level of insoluble proteins was always greater than that in soluble ones, but the specific fluorescence of insoluble fractions from young lenses was less than that of soluble older lenses. The greater fluorescence per unit protein may be just a manifestation or marker of the insolubilization process. Furthermore, because a threshold level of specific fluorescence was observed in the cortical fraction of clear lenses, it is likely that fluorophor formation is not a marker of aging in this region, as it is in the nuclear region in which the specific fluorescence increases with increasing age, perhaps reaching a threshold level beyond which cataractogenesis may occur.


Modulation of myo-[3H]inositol uptake by glucose and sorbitol in cultured bovine lens epithelial cells. I. Restoration of myo-inositol uptake by aldose reductase inhibition. The association between high-ambient glucose, the polyol pathway, and aldose reductase inhibition on in vitro myo-[3H]inositol uptake was examined in cultured bovine lens epithelial cells (BLECs). Myo-[3H]inositol accumulation in the presence of 5.5 mmol/l D-glucose was rapid and linear for 8 hr. When Na+ was replaced on an equal molar basis with N-methyl-D-glucamine chloride, myo-[3H]inositol uptake was reduced by more than 95%. The myo-inositol transport system appear to be distinct from glucose transport, based upon three criteria: (1) 2-deoxy-D-[3H]glucose uptake, unlike myo-[3H]inositol uptake, was largely sodium independent; (2) L-glucose was a competitive inhibitor of myo-[3H]inositol uptake but had no effect on 2-deoxy-D-[3H]glucose uptake; and (3) 2-deoxy-D-[3H]glucose uptake appeared independent of myo-inositol concentration. Sodium-dependent myo-[3H]inositol uptake was substantially inhibited after chronic (20 hr) exposure of cultured cells to 40 mmol/l glucose. Inhibition of aldose reductase activity partially prevented the inhibitory effect of glucose on myo-[3H]inositol accumulation. No significant difference in the rates of passive efflux of myo-[3H]inositol from preloaded high glucose-treated and control cultures was observed. Although the coadministration of sorbinil to the high-glucose medium partially protected against the attendant decrease in transport activity, the failure to normalize myo-[3H]inositol uptake suggested that glucose-sensitive and sorbitol-sensitive processes were involved in the uptake of myo-inositol.


Modulation of myo-[3H]inositol uptake by glucose and sorbitol in cultured bovine lens epithelial cells. II. Characterization of high- and low-affinity myo-inositol transport sites. Myo-[3H]inositol accumulation in cultured bovine lens epithelial cells (BLECs) occurred by high- and low-affinity, Na(+)-dependent transport sites. The high- and low-affinity transport systems had a Km of 27 +/- 4 and 157 +/- 22 mumol/l, respectively, and Vmax of 652 +/- 35 and 2952 +/- 308 pmol/mg protein/hr, respectively. The uptake of myo-[3H]inositol was lowered after chronic (20 hr) incubation of cultured cells in 40 mmol/l glucose throughout the concentration range for 1.5-400 mumol/l myo-inositol. The coadministration of sorbinil (0.1 mmol/l) to 40 mmol/l glucose partially prevented the inhibitory effect of glucose on myo-[3H]inositol uptake. Although the aldose reductase inhibitor prevented the inhibitory effect of glucose on the low-affinity transport site, a glucose-sensitive process for myo-[3H]inositol uptake on the high-affinity transport site was uncovered by Lineweaver-Burk analysis. Acute exposure (3 hr) of cultured BLECs maintained in physiologic medium (Eagle's minimal essential medium, 5.5 mmol/l glucose) to a range of 5.5-44 mmol/l glucose plus sorbinil also caused a decrease in myo-[3H]inositol uptake. Dixon plot analysis confirmed that the acute effect of glucose was the result of competitive inhibition of the high-affinity myo-inositol transport site. Acute exposure of cultured cells to 10-40 mmol/l sorbitol also diminished the accumulation of myo-[3H]inositol. Dixon plot analysis established that the acute effect of exogenous sorbitol was the result of competitive inhibition of the low-affinity myo-inositol transport site.(ABSTRACT TRUNCATED AT 250 WORDS)


GM1 reduces injury-induced metabolic deficits and degeneration in the rat optic nerve. This study demonstrates the earliest reported effects of GM1 treatment on crush-injured axons of the mammalian optic nerve. GM1, administered intraperitoneally immediately after injury, was found to reduce the injury-induced metabolic deficit in nerve activity within 2 hr of injury, as measured by changes in the nicotine-amine adenine dinucleotide redox state. After 4 wk, transmission electron microscopy 1 mm distal to the site of injury revealed a sevenfold increase in axonal survival in GM1-treated compared to untreated injured nerves. These results emphasize the beneficial effect of GM1 on injured optic nerves as well as the correlation between immediate and long-term consequences of the injury. Thus, these results have implications for treating damaged optic nerves.


Guanine nucleotide binding proteins in the dual regulation of lacrimal function. The purpose of this study was to identify and characterize functional G proteins that couple regulatory peptides with lacrimal secretory functions. Membranes were prepared from isolated rat exorbital lacrimal gland acini, and guanosine 5'-triphosphate (GTP)-dependence of adenylyl cyclase activity, known to be coupled with regulation of secretion, was measured. The guanine nucleotide GTP produced a biphasic response in the activity of membrane-bound adenylyl cyclase during a 10 min incubation with a maximum stimulation at 10(-5) mol/l GTP. Significant inhibition occurred at a dose of 10(-3) mol/l GTP, with cyclic adenosine monophosphate (cAMP) production reduced to less than basal levels. The effect of ADP-ribosylation of membrane proteins by the toxins produced by Vibrio cholera or Bordetella pertussis on lacrimal adenylyl cyclase was assessed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, autoradiography, and laser densitometry. Cholera toxin treatment of membranes resulted in dose-(0.5-100 micrograms/ml) and time-dependent (0-45 min) adenosine diphosphate (ADP)-ribosylation of two membrane proteins with M(r) values of 42,000 and 45,000. Pertussis toxin treatment resulted in the specific ADP-ribosylation of a single protein that migrates with an M(r) value of 41,000. This also was dose (0.5-25 micrograms/ml) and time dependent (0-30 min). Incorporation of 32P into the 45,000 M(r) and 42,000 M(r) proteins in the presence of 50 micrograms/ml cholera toxin was guanine nucleotide dependent, with a two- to threefold increase in labeling when the membranes were incubated with 1 or 0.5 mmol/l GTP. This effect was enhanced in the presence of the nonhydrolyzable GTP analog GTP gamma S.(ABSTRACT TRUNCATED AT 250 WORDS)


The mushroom femoral head. A radiographic investigation. In 1913, anthropologist Ales Hrdlicka described a number of femora as having "mushroom heads," a deformity he attributed to arthritis deformans. The authors have attempted to define the cause of this condition. Forty of 41 femora with "mushroom" femoral heads collected by Hrdlicka were grossly inspected and examined with plain radiographs and with computed tomography. Femoral neck angulation and degree of anteversion were determined. Three distinct categories were established: group I, those specimens with normal angulation and short femoral necks; group II, those with varus angulation and short femoral necks; and group III, those with normal-sized femoral necks and normal femoral neck angulation. No correlation was found between degree of anteversion and the categories. Additionally, most of the mushroom deformities were related to osteophyte formation. Most of the changes in the femora were the result of osteoarthritis. Two groups showed evidence of growth disturbances that occurred early in life. The changes in the second group were similar to those seen in Legg-Calvé-Perthes disease.


Development of a 2,048 x 2,048-pixel image intensifier-TV digital radiography system. Basic imaging properties and clinical application. A 2,048 x 2,048-pixel matrix image intensifier (II)-TV digital radiography system has been developed. Potential clinical applications of this new II-TV system were investigated. Basic imaging properties were assessed with clinical applications to gastrointestinal (GI) tract and chest examinations. Basic imaging properties showed improvement of modulation transfer functions (MTFs) from the 1,024 x 1,024- to the 2,048 x 2,048-pixel matrix and approximated the screen-film system at low spatial frequencies. Receiver operating characteristic (ROC) curves of simulated linear shadows improved similarly. Clinical applications showed that the image quality of the 2,048 x 2,048-pixel matrix was comparable with that of the screen-film system for upper GI and chest radiography, but the image quality of the screen-film system was better for the lower GI tract. The authors' II-TV digital radiography system is clinically applicable to gastrointestinal and chest examinations.


Image selection for computed tomography of the chest. A sampling approach. High-resolution computed tomography (HRCT) is useful to characterize the presence and extent of lung abnormalities. Contiguous HRCT images of the chest would require 200 images, which is not for practical due to 1) the extensive examination and reading time, and 2) radiation exposure. This article presents a methodologic framework to select the appropriate number of HRCT images to estimate any quantitative parameter with a desired precision. Alternative sampling strategies are introduced, and the sample size requirements are given. Sample size requirements are developed for the percentage of emphysematous lung using simple random and stratified random sampling. The effect of the number of strata on the sample size requirement also is shown. The marked reduction in the number of HRCT images using different types of sampling plans illustrates the power of sampling techniques. Proper stratification is critical to reduce the sample size requirement and to avoid missing key abnormalities, which is particularly critical in the early stages of any disease process when intervention may be most useful. Prior knowledge of the disease is useful in determining the optimum number and location of strata, and can be obtained from available chest radiographs, pulmonary function tests, radionuclide studies, and clinical parameters.


Efficacy of adjunctive intrathrombic heparin with pulse spray thrombolysis in rabbit inferior vena cava thrombosis. The efficacy and speed of pharmacomechanical thrombolysis may be limited by thrombotic effects of activated platelets and thrombin within the lysing clot. The authors designed an animal model of subacute venous thrombosis which was used to evaluate the effect of intrathrombic versus intravenous heparin during thrombolysis. Inferior vena cava (IVC) thrombosis was induced in rabbits by balloon catheter injury and placement of steel coils. Venacavagrams were obtained 48 hours later to document clot formation and for angiographic estimation of clot volume. Pulse-spray thrombolysis was performed by forceful injections of various agents through a catheter with multiple side holes spanning the clot. Most animals were given aspirin (30 mg orally) before treatment. After 1 hour of therapy, repeat venacavography was performed. Animals were killed, and residual clot weight was determined. Occlusive IVC thrombi were present in 94% of rabbits at 2 days. Mean residual clot weight per milliliter of estimated initial clot volume (mg/mL) for the various treatment groups was as follows: saline (n = 5) 632 +/- 54; tissue-type plasminogen activator (t-PA) 3 mg, (n = 6) 443 +/- 162; t-PA 3 mg + heparin 750 U intravenously, (n = 7) 408 +/- 128; t-PA 3 mg + heparin 500 U intrathrombic + heparin 250 U intravenously, (n = 8) 213 +/- 166. Differences among these groups (except t-PA alone versus t-PA + intravenous heparin) were significant. The extent of lysis with intrathrombic + intravenous heparin was not significantly retarded by withholding aspirin (n = 6, 194 +/- 72), or improved by giving half the intrathrombic heparin before t-PA injections (n = 6, 280 +/- 158). The results demonstrate the advantage of adjunctive intrathrombic + intravenous heparin over intravenous heparin alone in increasing the extent of pulse-spray thrombolysis in this IVC thrombosis model.


Reflux of ethanol during experimental liver ethanol injections. The reflux of ethanol into the peritoneal cavity during percutaneous ethanol injection therapy (PEIT) of liver neoplasms may cause pain and other side effects. This article studies the optimal injection technique to minimize the reflux of ethanol. A technique using normal postmortem pig livers was developed to measure the amount of reflux in different experimental injection situations. The proportional reflux increased significantly when the needle diameter (0.55-1.1 mm) was larger (P < .01) and when the injection was more superficial (P < .0005) (ie, the needle traversed a shorter distance [1-5 cm] inside the liver tissue). Speeding up the injection (0.13-1.5 g/second) produced suggestive (P < .10) increase of the proportional reflux. The proportional reflux was not affected by either the ethanol dose (0.40-2.06 g) or by the time lapse (0-30 seconds) after the injection when the needle was left in situ before its withdrawal. The reflux of ethanol during PEIT is influenced by the diameter of the needle and by the technique used. Further studies are needed to fully clarify the clinical validity of these results.


Early effect of gadopentetate and iodinated contrast media on rabbit kidneys. The authors compared the physiologic and nephrotoxic effects of the magnetic resonance imaging contrast medium gadopentetate with two conventional radiographic contrast media. Rabbits were injected intravenously with one of the following solutions: 1) gadopentetate (0.1 M); 2) iohexol (300 mg I/mL); 3) metrizoate (300 mg I/mL); and 4) NaCl (0.9%). Blood samples were taken before and 5, 15, 45, 90, and 180 minutes after injection of the solutions and were analyzed for creatinine, aldosterone, and contrast media levels. Urine was sampled before and 1, 2.5, and 5 hours after injection of the solutions, and creatinine, leucine amino peptidase (LAP), alkaline phosphatase (ALP), gamma glutaryl transferase (GGT), and N-acetyl beta-D-glucosaminidase (NAG) activities were quantified. Contrast media clearance was similar for gadopentetate, iohexol, and metrizoate. Plasma aldosterone was significantly higher in the two groups injected with iodinated contrast agents compared with the gadopentetate and saline groups in the 3-hour samples. During the 5 hours after injection, the excretion of brushborder enzymes LAP, ALP, and gamma GT was significantly higher for all contrast media compared with pre-contrast values and 0.9% NaCl controls. NAG, a lysosomal enzyme from tubular cells, showed a significant increase compared with pre-contrast values for all contrast media. Intravenous injection of gadopentetate in rabbits showed nephrotoxicity of the same order as that of conventional iodinated contrast media.


Real-time dynamics of an extravascular magnetic resonance contrast medium in acutely infarcted myocardium using inversion recovery and gradient-recalled echo-planar imaging. The purposes of this study are to evaluate the first-pass profile of gadolinium-BOPTA/Dimeg (Gd-BOPTA/Dimeg) during its transit through hearts subjected to acute myocardial infarction, and to delineate these infarcted regions by the use of ultrafast magnetic resonance imaging (MRI). Regional ischemia was induced in anesthetized rats by occluding the left coronary artery. Imaging parameters for single shot EPI included TE, 10 mseconds; AT, 33 mseconds; and 64 x 64-pixel matrix. Consecutive images were obtained every 1 to 2 seconds over a 30-second period. After approximately two images, Gd-BOPTA/Dimeg was injected intravenously (0.05 and 0.25 mmol/kg). Gd-BOPTA/Dimeg (0.05 mmol/kg), with inversion recovery EPI, produced a substantial increase in signal intensity of right and then left ventricular blood. Normally perfused myocardium also was enhanced, but not the acutely infarcted region. Clear delineation of the infarcted region as negatively enhanced "cold spots" persisted for at least 20 seconds. Gd-BOPTA/Dimeg (0.25 mmol/kg) with standard gradient-recalled EPI produced a different profile of signal intensity changes. Signal intensities of ventricular blood and normal myocardium were greatly reduced, leaving the infarcted zone as a positively enhanced "hot spot." Delineation of the infarcted region persisted for 6 to 8 seconds. The infarcted zone detected with MRI corresponded to that observed at autopsy. Regions of acute myocardial infarction can be detected as negatively enhanced "cold spots" or positively enhanced "hot spots" by studying the first-pass dynamics of Gd-BOPTA/Dimeg through hearts with regional ischemia by use of single shot EPI.


Magnetic resonance imaging demonstration of pharmacologic-induced myocardial vasodilatation using a macromolecular gadolinium contrast agent. Adenosine is a potent vasodilator used clinically in nuclear scintigraphy to assess coronary artery reserves. The potential to identify this vasodilating effect of adenosine using magnetic resonance imaging (MRI), which is superior in spatial resolution to nuclear scintigraphy, combined with a blood-pool MRI contrast agent, was investigated in normal rats. Groups of Sprague-Dawley rats received successive infusions of either adenosine (3 mg/kg/minute; n = 7) or dipyridamole (negative control; up to 1.0 mg/kg/minute; n = 9), both before and after contrast enhancement, with a macromolecular blood-pool MRI contrast agent, albumin-gadolinium-DTPA35 (Gd-DTPA35) (4.0 mumol Gd per kilogram). Electrocardiographically (ECG) gated MRIs (2.0 Tesla), acquired serially before and after contrast enhancement, and with and without either adenosine or dipyridamole infusions, to monitor potential pharmacologic responses. During repeated infusions of adenosine, the postcontrast myocardial enhancement, reflecting blood volume, increased significantly (P < .05), up to 150%, compared with pre-adenosine enhancement. Infusions of dipyridamole, pharmacologically inactive in rats, produced no change in myocardial enhancement. The increased myocardial signal intensity observed during adenosine infusions after enhancement of the blood pool can be attributed to increased blood volume accompanying coronary vasodilatation. The method, which does not require a continuous infusion of contrast agent, has potential for the clinical evaluations of coronary artery reserves.


The effect of the temperature of contrast media on cardiac electrophysiology and hemodynamics during coronary arteriography. The authors assess the effect of preheating ionic and nonionic contrast media on regional electrophysiologic and/or hemodynamic side effects during coronary arteriography. The authors injected 6 mL of nonionic (iohexol) and ionic (ioxaglate) low-osmolality contrast media and NaCl 0.9% twice, at 20 degrees C and 37 degrees C, into the left coronary artery in eight open-chest dogs. To study regional electrophysiologic effects, the authors measured monophasic action potential duration (MAPD) using an epicardial suction electrode placed in the contrast-perfused area. Hemodynamic effects were studied by recording left ventricular systolic pressure (LVSP), mean aortic pressure, LV end diastolic pressure (LVEDP), LV dP/dtmax, and cardiac output. Ioxaglate and iohexol prolonged MAPD more at 20 degrees C than at 37 degrees C. NaCl 0.9% prolonged MAPD only when injected at 20 degrees C. The temperature of iohexol did not significantly influence LV pressures (LVPs) or LV dP/dtmax. Ioxaglate increased LVEDP and decreased LV dP/dtmax more at 20 degrees C than at 37 degrees C 10 seconds after injection. In dogs, contrast media, preheated to body temperature before selective injection during coronary arteriography, reduced dispersion of repolarization and reduced the risk of serious cardiovascular complications.


A new method for thermocholecystectomy. Initial experience and comparison with other techniques. The authors tested the feasibility of thermocholecystectomy for gallbladder ablation in an animal model. Thermal treatment of the cystic duct followed by heating of the saline-filled gallbladder using a separately designed heater/expander was performed in 13 pigs (group I). In four animals, heating of the gallbladder alone was performed (group II). Two animals served as controls (group III). All animals were killed 12 weeks after treatment. There was cystic duct occlusion in 10 (77%) of 13 of group I animals. In 6 (60%) of 10 of these animals with cystic duct occlusion, there was complete ablation of the gallbladder mucosa and complete obliteration of the gallbladder lumen. In group II animals, all cystic ducts were intact with an unchanged gallbladder volume in all four animals (100%), and normal gallbladder mucosa were intact in three (75%) of four animals. The gallbladders and cystic ducts in group III animals were normal. This study demonstrates many technical difficulties with thermal cholecystectomy. However, under ideal conditions, permanent gallbladder ablation is feasible in our animal model using a specially designed heating system.


Radiography of the carpal scaphoid. Experimental evaluation of "the carpal box" and first clinical results. The authors describe a new device ("the carpal box") for the radiographic detection of occult scaphoid fracture. Fractures in the scaphoid of five cadaver specimens were mechanically produced. Subsequent examinations included conventional scaphoid radiography, multi-angle radiography, and radiography using the new device. The anatomic analysis of the specimens served as the standard for comparison. A pilot study was performed in six consecutive patients with suspected scaphoid fracture. Neither scaphoid radiography nor multi-angle radiography could confirm a fracture in two specimens, whereas all fractures were recognized on the carpal box radiographs. All scaphoid fractures were visualized by carpal box radiography, whereas scaphoid radiography was equivocal in one patient and negative in the other. Carpal box radiography may have additional value in the diagnosis of occult scaphoid fracture. This may lead to a reduction in costs and inconvenience for patients with clinically suspected scaphoid fracture and negative scaphoid radiography.


Research in the clinical radiology department. Researchers often feel tangled in a web of bureaucracy when attempting to conduct their research. However, it is vital that researchers get involved and develop review processes such as those described above, which facilitate animal research yet address the important ethical, legal, and other related issues raised by hospital administrators and the public. As we do so, it is vital that we communicate directly with the public. Without this participation, we will find more and more hospital radiology departments closing their doors to animal-based research.


Moonlighting during the radiology residency. The authors surveyed current residents and practicing radiologists to assess motivations for and attitudes about radiology moonlighting during residency. One thousand one hundred current fourth-year radiology residents and 1,100 practicing radiologists who finished training within the past 10 years were surveyed. Information was solicited concerning motivations for and attitudes toward moonlighting and the effects of moonlighting on residents' training. Current residents were compared with former residents to assess changes in attitudes about moonlighting. There were no important differences in the practicing and training cohorts. Of each group, 52% moonlighted. Debt was the main motivating factor influencing a resident's decision to moonlight. Moonlighters owed significantly more money (average debt, $25,804) at the beginning of their residency than did non-moonlighters (average debt, $19,554). In addition, 72% of moonlighters had to begin loan repayments during training with average monthly payments of $284. Departmental policy was less of an influencing factor. There was no statistical difference in the way moonlighters and non-moonlighters spent their time with respect to clinical work, reading radiology, or participating in research. Residents moonlight primarily for financial reasons but also perceive a positive educational benefit. Although no significant negative effects on the residency were found in this study, rising debt, decreased forbearance of repayment, and possible resultant increases in the amount of time spent moonlighting, might eventually affect resident's productivity in more traditional residency activities.


Radiology on the air. A continuing medical education experiment. The purpose of Radiology on the Air was to assess the technical and educational feasibility of providing radiologic continuing medical education via a fully interactive live telecommunications network. Thirty-nine radiologic conferences were broadcast over the communications network of the Microelectronics Center of North Carolina (MCNC). Category 1 credit for the Physicians Recognition Award of the American Medical Association was available to participants who returned a completed program evaluation sheet by mail. Three participating academic institutions regularly offered the programming to a total of 684 participants, of whom 129 viewed programs at distant sites. Despite adequate-to-excellent technical quality and positive feedback concerning educational content, no continuing medical education (CME) credits were issued by the parent institution. The Radiology on the Air experiment suggests that a live telecommunications network is a capable vehicle for providing CME in radiology.


Partial thoracic aortic occlusion in blunt trauma. This case raises some interesting points. First, it allows a review of Poiseuille's Law and its application to vascular disease. It raises the question of whether or not some CT and MRI findings are of clinical significance. Finally, one must question whether or not intervention is indicated based on these "high tech" findings. Only the passage of time and accumulation of further data will give us the correct answers.


A study of the relationship between severity of illness and hospital cost in New Jersey hospitals. In response to concerns over the equity of diagnosis-related group (DRG)-based prospective payment, the New Jersey Department of Health conducted a Severity of Illness evaluation study in which severity of illness, DRG, and uniform cost information were collected for 76,798 patients in 25 hospitals. Severity of illness was measured using the Computerized Severity Index (CSI) and was found to be a significant determinant of hospital cost in 76 DRGs that accounted for 41.4 percent of the total direct hospital patient care costs and 27 percent of the patients. The addition of CSI severity levels to the 76 DRGs reduced the coefficient of variation of cost in these DRGs by 17.4 percent and improved the overall reduction in variance of cost within the 76 DRGs by 38.2 percent. The change in total hospital payments due to the addition of severity for the 76 DRGs varied from a positive 5.71 percent to a negative 5.48 percent. These results demonstrate that a severity adjustment to this subset of DRGs would result in a more equitable DRG-based prospective payment system.


Choosing quality of care measures based on the expected impact of improved care on health. Consumers, payers, and policymakers are demanding to know more about the quality of the services they are purchasing or might purchase. The information provided, however, is often driven by data availability rather than by epidemiologic and clinical considerations. In this article, we present an approach for selecting topics for measuring technical quality of care, based on the expected impact on health of improved quality. This approach employs data or estimates on disease burden, efficacy of available treatments, and the current quality of care being provided. We use this model to select measures that could be used to measure the quality of care in health plans, but the proposed framework could also be used to select quality of care measures for other purposes or in other contexts (for example, to select measures for hospitals). Given the limited resources available for quality assessment and the policy consequences of better information on provider quality, priorities for assessment efforts should focus on those areas where better quality translates into improved health.


How the elderly fare in HMOs: outcomes from the Medicare competition demonstrations. Because of concern about the effects of prepaid care on outcomes for elderly enrollees in health maintenance organizations (HMOs), a prospective study of access to care and functional outcomes was performed. HMOs with Medicare risk contracts in January 1985 (N = 17) were selected from ten communities and were matched for comparison with ten similar communities where no Medicare HMOs were in operation. Random samples of HMO enrollees (N = 2,098) and fee-for-service (FFS) nonenrollees (N = 1,059) were assessed at baseline and at follow-up one year later (HMO = 1,873, FFS = 916) to observe access to care and functional outcomes. At baseline, nonenrollees had more bed days and poorer functional status than HMO enrollees. While fewer HMO enrollees experienced declines in functional status between baseline and follow-up (e.g., patient's ability to function declined in one or more activities of daily living: HMOs at 5.3 percent versus FFS at 8.5 percent, p < .01), after controlling for other factors with logistic regression, enrollment status was not significantly associated with functional decline. Self-rated health, history of hospitalization, age of 80 or older and baseline functional status were predictive of decline in function. After controlling for baseline differences, HMO disenrollees also experienced similar functional declines at follow-up compared to continuously enrolled beneficiaries. These findings suggest that Medicare beneficiaries who belong to HMOs experience comparable rates of functional decline to those experienced by beneficiaries in the FFS sector with similar initial levels of function and health status. Together with results showing no significant difference in medical visits according to various symptoms, we conclude that access and quality of care delivered by HMOs is comparable to that provided in FFS settings.


The effect of the illness episode approach on Medicare beneficiaries' health insurance decisions. This article reports on a quasi-experimental test of the Illness Episode Approach (IEA), a new approach to providing Medicare beneficiaries with information about the financial consequences of alternative health care coverage decisions. Beneficiaries were randomly assigned to free, three-hour workshops, half using materials developed through application of the IEA, half using traditional comparative information on insurance options. Analysis of data collected before and after the workshops indicates that participants in the Illness Episode sessions were more likely to drop duplicative coverage, to spend less on premiums, and to report that their decisions to change coverage had met their expectations. The entire sample of workshop participants showed significant increases in knowledge of Medicare and their own insurance, as well as improved satisfaction with the cost of their health care coverage.


Determinants of hospital tax-exempt debt yields: corrections for selection and simultaneous equation bias. The cost of capital for hospitals is a topic of continuing interest as Medicare's new capital payment policy is implemented. This study examines the determinants of tax-exempt revenue bond yields, the primary source of long-term capital for hospitals. Two important methodological issues are addressed. A probit analysis estimates the probability that a hospital or system will be observed in the tax-exempt market. A selection-corrected two-stage least squares analysis allows for the simultaneous determination of bond yield and bond size. The study is based on a sample of hospitals that issued tax-exempt revenue bonds in 1982-1984, the years immediately surrounding implementation of Medicare's new payment system based on diagnosis-related groups, and an equal number of hospitals not in the market during the study period. Results suggest that hospital systems and hospitals with high occupancy rates are most likely to enter the tax-exempt revenue bond market. The yield equation suggests that hospital-specific variables may not be good predictors of the cost of capital once estimates are corrected for selection.


[Importance of MRI in hydronephrosis caused by acute or chronic ureteral obstruct. Prospective study]. Magnetic resonance imaging (MRI) of the normal kidney shows in T1 weighted sequence a spontaneous corticomedullary differentiation. In case of ureteral obstruction the corticomedullary differentiation tends to disappear, the medullary signal intensity in T1 weighted sequence is lower and the whole kidney signal intensity in T2 weighted sequence is greater in acute phase. 16 patients with lithiasis ureteral obstruction were evaluated in MRI study. A T1 weighted S.E. 500/28 sequence in axial and frontal planes (7 mm thick-section) and a T2 weighted E.G. 2000/40 sequence in axial plane were used to study the hydronephrotic kidney and to compare it with contralateral normal kidney. Ultrasounds and intravenous pyelography (IVP) were performed to assess the renal dysfunction. MRI realize a morphologic study of the kidney which can be compared with ultrasounds and IVP. MRI assess renal function by the signal intensity but the time of obstruction and the time of medical treatment before MRI are of interest.


[Magnetic resonance, a means for anatomically reliable imaging and noninvasive metabolic studies of kidney transplants]. As an adjunct to the monitoring of intracellular high-energy phosphorus metabolites by 31P NMR1 for assessment of renal viability, a study of vasculature of preserved kidneys was performed by Image-Guided Volume Selective 19F MR Spectroscopy. 1H and 19F of the same preserved rat and porcine kidneys were obtained. The technique enabled the analysis of the vessel and tissue properties and opens new possibilities for pretransplant assessment of renal vasculature.


[Ureterorenoscopy as a diagnostic procedure in the upper urinary tract]. Ureteropyeloscopy has become a valuable asset in the diagnosis and treatment in the upper urinary tract. From 1984 to 1991 we performed 1635 ureteropyeloscopies, 180 procedures in a diagnostic intention. Rigid ureteropyeloscopes permit endoscopic access into the ureter and the upper calix, actively deflectable instruments are necessary to visualize the middle and lower calix.


[Systematic morphometry of radical prostatectomy samples. A guideline for general practice]. The predictive value of quantitated tumor volume for the prognosis of the individual patient with prostate cancer has been established in analysis of more than 500 radical prostatectomy specimens at Stanford Medical Center. The Stanford technique for detailed tissue sectioning involves considerable time and expense plus computer planimetry. Therefore we have developed two simplified protocols which are suitable to routine diagnostic pathology. Histologic slides of 145 radical prostatectomy specimens, as evaluated by the Stanford technique, were reviewed and a selection of slides was made in a systematic fashion according to two protocols ("bilateral" and "parasagittal"). Tumor volume was estimated manually from this reduced sample of slides by comparing cancer areas to a millimeter grid. The bilateral protocol used an average of 11.7 slides per case (range 8-20), the parasagittal protocol used an average of 8.8 slides per case (range 6-15) versus an average of 26.2 slides per case (range 16-67) by the original Stanford technique. Volume estimates were within +/- 20% of true (computer) volume in 96% and 89% of cases, respectively. A simplified tissue sampling technique can yield accurate cancer volume determinations in radical prostatectomy specimens with reduced time and expense.


[Randomized study comparing zoladex versus zoladex plus flutamide in treatment of advanced cancer of the prostate]. 589 patients from 10 countries are recruited into a multicentre randomised trial comparing Zoladex with a combination of Zoladex-Depot + flutamide. Zoladex was administered as a depot injection every 28 days and flutamide was given as 3 x 250 mg tablets daily. Patients with histologically confirmed locally advanced (T3/T4) or metastatic (M1) carcinoma were included. Patients with previous hormonal manipulation and/or chemotherapy were excluded. 65% of patients had metastatic disease. Both treatment groups were balanced (T-category, histology, metastases, performance status). An analysis of subjective and objective response, time to response and time to progression has shown no statistically significant difference. A survival analysis after a median follow-up of 24 months has shown no statistically significant difference between the two treatment groups (p = 0.47).


[Autologous blood transfusions in interventions of the pelvis using the cell saver]. From July 1990 to September 1991 we used the cell-saver for autologous intraoperative retransfusion in 8 radical prostatectomies, 5 cystectomies and one adenomenucleation. Postoperatively we tolerated a hemoglobin fall up to 10 g/100 ml. Doing it without heterologous blood was possible in 7 out of 14 patients. In all of them the preoperative hemoglobin was higher than 13 g/100 ml and the blood loss did not exceed 3000 ml.


[Malignant mesothelioma of the tunica vaginalis testis]. Malignant mesothelioma of the tunica vaginalis testis is an extremely rare tumor, with only 37 cases previously described in the literature. Treatment consists of inguinal orchiectomy with close follow-up [1]. Asbestos exposure, trauma and hydrocele have been implicated as risk factors. We describe a patient's history and the pathological findings as well as the management according to preceding reports in the literature.


[Kaposi's sarcoma of the urinary bladder after kidney transplantation]. In 1872 the Viennese dermatologist Moritz Kaposi first described a pigment sarcoma of the skin. A modification of the epidemiology and the follow-up results in the accumulation of reports about the Kaposi-sarcoma after organ transplantation in the sixties and in the beginning of the eighties frequently Kaposi-sarcomas by the immunodefect syndrome AIDS were noticed. The incidence of Kaposi-sarcomas after kidney transplantations is estimated to be 0.3 to 1.8 per thousand. We report about a patient developing a Kaposi-sarcoma of the bladder during an immunosuppression therapy with Imurec and Sandimmun.


[Screening study for early detection of intestinal tumors after urinary diversion]. The increased risk of colon carcinoma following urinary diversions via colon makes knowledge about preneoplastic changes necessary. In 30 ureterosigmoidostomy patients with a mean observation period of 16 years flexible sigmoidoscopy with biopsies and nitrosamine analysis of the feces/urine mixture have been performed. In the biopsies we found an increased sialomucin concentration at the ureterocolonic anastomosis in 29.2%--sialomucin is supposed to be a preneoplastic change--with no significant difference to the mucosa periureteral and in the rectum. In 58.3% we found chronic inflammation at the anastomosis, in 29.2% periureteral and 4.2% in the rectum. 2/30 patients developed adenocarcinoma, 1 patient an atypia and 1 patient a juvenile polyp. The nitrosamine excretion of the ureterosigmoidostomy patients were significantly increased compared to 20 healthy controls with no correlation to the histology at the anastomosis or the observation time. Because of the multilocular presence--colon carcinomas develop only at the anastomosis--sialomucin and chronic inflammation seem to be no preneoplastic changes in urinary diversions. The nitrosamine analysis is not suitable for routine follow-up as well.


[Marfan syndrome and cystic kidneys of the adult type]. For the first time Bernhard Marfan described the Marfan-Syndrome in 1896; it is a meso- and ectodermed variety with the conducting symptom of "arachnodactyly". Marfan-Syndrome is an autosomal dominant hereditary disorder with high penetrance and variable expressivity. In our opinion this case of a 41-year-old patient with kidney cysts and aneurysma dissecans of the arteria ascendens by Marfan-Syndrome was described in the literature only twice. The casuistics of this Marfan-Syndrome patient shows a particular rare associated organ-change--the kidney cysts--and illustrate the frequency of this hereditary disease.


HLA class I nucleotide sequences, 1992.

HLA class I nucleotide sequences, 1992. The HLA class I sequences included in this compilation are taken from articles listed in the literature: "Nomenclature for Factors of the HLA System, 1991" [1], "Nomenclature for Factors of the HLA System, 1990" [2], and "Nomenclature for Factors of the HLA System, 1989" [3]. Because of the increased number of sequences, we have only included sequences for exons 2-4 in this compilation. Where discrepancies have arisen between reported sequences, the original authors have been contacted where possible, and necessary amendments to published sequences have been incorporated into this alignment. Future sequencing may identify errors in this list, and we would welcome any evidence that helps to maintain the accuracy of this compilation. In the sequence alignments, identity between nucleotides is indicated by a hyphen (-). An unavailable sequence is indicated by a period (.). Gaps in the sequence are inserted to maintain the alignment between different alleles showing variation in amino acid number.


Ancestral haplotypes: conserved population MHC haplotypes. We describe here a number of Caucasoid MHC haplotypes that extend from HLA-B to DR and that have been conserved en bloc. These haplotypes and recombinants between any two of them account for 73% of unselected haplotypes in our Caucasoid population. The existence of ancestral haplotypes implies conservation of large chromosomal segments. Irrespective of the mechanisms involved in preservation of ancestral haplotypes, it is clear that these haplotypes carry several MHC genes, other than HLA, which may be relevant to antigen presentation, autoimmune responses, and transplantation rejection. In light of the existence of ancestral haplotypes, it is critical to evaluate MHC associations with disease and transplantation outcome in terms of associations with ancestral haplotypes rather than individual alleles.


Leucine33-proline33 substitution in human platelet glycoprotein IIIa determines HLA-DRw52a (Dw24) association of the immune response against HPA-1a (Zwa/PIA1) and HPA-1b (Zwb/PIA2). Alloantibody formation against HPA-1a (Zwa/PIA1) has, to date, only been found in HLA-DRw52(a+) (Dw24) individuals. Alloimmunization against the product of the other HPA-1 allele, HPA-1b, is rare. We have been able to evaluate ten cases of HPA-1b alloimmunization in Europe in order to study whether there is an association between HLA phenotype and anti-HPA-1b antibody formation. HLA typing of these patients was performed with particular attention to the DRw52a specificity using specific T-cell clones. No association with DRw52a or any other known HLA phenotype was found. This finding implies that the amino acid substitution leucine33-proline33 in GPIIIa, responsible for HPA-1a/b, is of primary importance for the association of anti-HPA-1a antibody formation with DRw52a. These data show that the amino acid polymorphism affects the presentation of the immunogenic oligopeptides of HPA-1a and -1b in the HLA class-II groove.


Polymerase-chain-reaction-based analysis of polymorphism in the HLA-B gene. The polymerase chain reaction (PCR) in combination with the sequence-specific oligonucleotide probe (SSOP) was applied to analyze the polymorphism in the exon 2 of the HLA-B gene. In this study, genomic DNAs from 85 B-lymphoblastoid cell lines homozygous for HLA and peripheral blood granulocytes of 156 Japanese individuals were investigated. Two HLA-B-specific 5'-sided primers (CG4 and CG5) and two 3'-sided primers (CG2 and CG3) were designed for specific amplification of the exon. HLA-B alleles were classified into two groups (groups I and II) according to specific amplification with two types of the 3'-sided primers. The amplified DNAs were hybridized with 23 nonradioactively labeled SSOPs. Based on the hybridization patterns with the SSOPs, 34 HLA-B specificities were divided into 26 epitope combination (EC) groups. Fifteen HLA-B specificities were classified into four EC groups and these HLA-B specificities could not be distinguished from one another in the same EC group. Another 16 HLA-B specificities corresponded one by one to 16 distinct EC groups, and two subtypes of HLA-Bw75, B27, and Bw48 were also identified enabling the accurate typing of 22 HLA-B alleles at the DNA level. Single-strand conformation polymorphism (SSCP) of the PCR products from group I HLA-B alleles was also investigated. The HLA-B alleles showed distinct electrophoretic patterns in nondenaturing polyacrylamide gels, depending on the nucleotide sequences of the exon 2, indicating that the SSCP analysis may be an alternative, useful and practical HLA-matching system of HLA-B specificity in tissue transplantation.


Shared polymorphism between gorilla and human major histocompatibility complex DRB loci. A high degree of polymorphism and high nucleotide diversity mark the functional genes of the major histocompatibility complex (Mbc). Alleles at the different Mbc loci can be classified into distinct lineages that are shared between species and, therefore, are presumed to have been founded before speciation. We have sequenced the most polymorphic part of 25 gorilla Mbc-DRB genes from six individuals. (The DRB genes code for the beta-polypeptide chain of the alpha beta heterodimer that constitutes one family of the class II MHC molecules.) Fifteen of the sequences identify new alleles at four DRB loci; each of the six gorillas was heterozygous at one of the loci at least. Thirteen of the alleles could be assigned to lineages identified previously; the remaining two alleles represent new lineages. All the major human DRB allelic lineages are now known to be shared with apes, and all must have originated before the human-gorilla-chimpanzee divergence more than six million years (my) ago. The presence of some of the gorilla and human lineages in Old World monkeys suggests that these lineages emerged before the divergence of apes and cercopithecids. We argue that the major allelic lineages at the DRB1 locus began to diverge shortly after the rounds of duplication that generated the different DRB loci now found in the hominoids and that this event occurred more than 30 my ago. Comparison of closely related gorilla DRB sequences indicates that polymorphism may be generated by several mechanisms: point mutations, slippage during DNA replication, and recombination. Deduced gene linkages provide evidence for transspecies evolution of haplotype polymorphism.


Analysis of human T-cell receptor alpha-chain cDNAs isolated from peripheral blood mononuclear cells. T-cell receptor alpha-chain cDNA were generated from unstimulated peripheral blood mononuclear cells of a DR2,3,52a individual using a modified anchor PCR method. Fifty-six cDNA clones were identified representing 47 distinct T-cell receptor clonotypes and 26 VA loci. This analysis identified a new VA gene family VA30, and a new member of the VA6 gene family.


One-tone suppression in the cochlear nerve of the gerbil. One-tone rate suppression has been reported several times for auditory nerve fibers of mammalian and non-mammalian vertebrates. Because its properties are very similar to those of two-tone rate suppression, the possibility exists that one-tone rate suppression is the result of an interaction within the inner ear of the suppressing tonal stimulus and some ongoing extraneous acoustic stimulus. For this reason, reports of one-tone rate suppression often elicit suspicions that the investigators were not sufficiently careful in controlling leaks in their acoustic barriers or in the electrical pathways to their acoustic drivers. Recent reports of one-tone rate suppression in pigeon basilar-papillar fibers and goldfish saccular fibers were accompanied by descriptions of measures taken to avoid such leaks. In this paper, we describe one-tone rate suppression in a mammal, the Mongolian gerbil; and we demonstrate that the background spike activity being suppressed is not driven by either external sounds coming from outside the acoustic isolation test chamber or by non-stimulus electrical inputs to the acoustic driver. The suppressed background spike activity evidently arises from sources within the animal. These sources may be non-acoustic, associated with spontaneous pre- or post-synaptic ion-channel activity; or they may be acoustic sources--internal sound or vibration generators.


The influence of loud sound on red blood cell velocity and blood vessel diameter in the cochlea. Using intravital microscopy, we observed both decreases in red blood cell velocity and possible vasoconstriction in stria vascularis capillaries of the rat cochlea in response to loud sound (Quirk et al., 1991). However, our observation of vasoconstriction was subject to error in measurements from the two dimensional images obtained with our silicon intensified (SIT) camera due to the influence of focus causing image blur. The purpose of the current study was to apply an extended focus microscopy technique to obtain quantitative assessment of vessel diameter changes (Avinash et al., 1992), as well as to extend these studies to the guinea pig model. Broad-band sound stimulation at intensities of 84 dB SPL and 110 dB SPL were used. The results show that loud sound induces a sequence of changes in cochlear blood flow. Stimulation with 110 dB SPL resulted in a mean increase (maximum = 27%) in red blood cell velocity for the first 20 min of exposure followed by a gradual decrease below baseline (minimum = -12%) prior to termination of the signal. This velocity decrease and subsequent recovery were associated with significant changes in vessel diameters of selected and measured capillaries. In contrast, the 84 dB SPL stimulus caused an increase in red blood cell velocity (maximum = 20%) and vessel diameter (mean = 7.5) during the stimulation period. No recovery was observed during the 10 min observation period following sound. Several possible mechanisms responsible for these changes are discussed.


Sensitivity of neurons in cat primary auditory cortex to tones and frequency-modulated stimuli. I: Effects of variation of stimulus parameters. In the primary auditory cortex (AI) of barbiturate-anesthetized cats multi-unit responses to tones and to frequency-modulated (FM) tonal stimuli were analyzed. Characteristic frequency (CF), sharpness of tuning, minimum threshold, and dynamic range of spike count--intensity functions were determined. Minimum threshold and dynamic range were positively correlated. The response functions to unidirectional FM sweeps of varying linear rate of change of frequency (RCF) that traversed the excitatory frequency response areas (FRAs) displayed a variety of shapes. Preferences for fast RCFs (> 1000 kHz/s) were most common. Best RCF was not correlated with measures of sharpness of tuning. Directional preference and sensitivity were quantified by a DS index which varied with RCF. About two-thirds of the multi-unit responses showed a preference for downward sweeps. Directional sensitivity was independent of CF and independent of best RCF. Measurements of latencies of phasic responses to unidirectional FM sweeps of different RCF demonstrated that the discharges of a given multi-unit over its effective RCF range were initiated at the same instantaneous frequency (effective Fi), independent of RCF. Effective Fis fell within the excitatory FRA of a given multi-unit. The relationships of effective Fis to CF show that responses were evoked only when the frequency of the signal was modulated towards CF and not when modulated away from it, and that responses were initiated before the modulation reached CF. Changes in the range and depth of modulation had only minor, if any, effects on RCF response characteristics, FM directional sensitivity, and effective Fis, as long as the beginning and ending frequencies of FM sweeps fell outside a multi-unit's FRA. Stimulus intensity also had only moderate effects on RCF response characteristics and DS. However, effective Fis were influenced in systematic fashions; with increases in intensity, effective Fis to upward and downward sweeps decreased and increased, respectively. Thus, for higher intensities FM responses were initiated at instantaneous frequencies occurring earlier in the signal. The results are compared with previous data on tone and FM sensitivity of auditory neurons in cortical and subcortical structures, and mechanisms of FM rate and directional sensitivity are discussed. The topographic representations of these neuronal properties in AI are reported in the companion report.


Derived and enhanced compound action potentials at near-threshold levels: forward masking increases sensitivity of audiograms and tuning curves. The amplitude of a cochlear nerve compound action potential (CAP) can be increased by forward maskers having levels close to the visual detection threshold of the CAP. This effect, termed enhancement, varies as a function of the frequency of the masker and probe stimulus, and is nonmonotonic with respect to the level of the masker. Other studies using the derived CAP have used a subtraction technique to evaluate the ability of simultaneous maskers having levels near the CAP visual detection threshold to influence the CAP produced by an above threshold tone. The present paper compares audiograms produced by the conventional nonmasked CAP visual detection threshold technique with audiograms produced by both forward masked derived CAPs and forward masked enhanced CAPs. In response to low and middle frequency stimuli, both masked CAP measures produce more sensitive audiograms than does the conventional nonmasking method. Forward masked amplitude tuning curves (TCs) were also produced, comparing the conventional 50% amplitude reduction and 20 microV amplitude reduction methods with TCs obtained with derived and enhanced CAPs. When the same criteria are used, both masked CAP measures result in sharply tuned amplitude TCs that are approximately 60 dB more sensitive than the conventional CAP technique. At near-threshold levels, the properties of forward masked enhanced and derived CAPs appear to be similar.