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Biomedical subjects

J Kaplan

Publications and source records attributed to J Kaplan.

At least 325 records · Page 18Linked to original sources
PubMed1985

Markers of genetic variation among the Waorani Indians of the Ecuadorian Amazon headwaters.

Until recently, the Waorani Indians of Ecuador's Amazon headwaters maintained a fierce resistance to all intruders into their territory, and as a result of their actions and reputations a population of 600 people controlled a very large territory (about 8,000 square miles). The isolation of the Waorani has resulted in a large linguistic and genetic distance from their neighbors. Our survey of red cell enzymes, immunoglobulin allotypes, and dermatoglyphics demonstrates that the Waorani are a highly inbred and homogeneous population. Of 18 red cell enzymes studied, the Waorani have a limited polymorphism for only 6. Only two Gm haplotypes (Gm1,2,17,21, Gm1,17,21) were found and 60% of those tested were homozygous for the Gm1,17,21 haplotype. All individuals were A2m (1) and 95% of these were homozygous. The Waorani's dermatoglyphic traits fell within the wide range found among other South American Indians with close affinity to the Ecuadorian Jivaro group. Despite the limitations of these genetic systems, they demonstrate that the Waorani share limited genetic traits with the neighboring Jivaro Indians and are isolated from other tribal populations in South America.

Dermatoglyphics↗
PubMed1985

Phenylarsine oxide-induced increase in alveolar macrophage surface receptors: evidence for fusion of internal receptor pools with the cell surface.

Rabbit alveolar macrophages which were treated at 0 degrees C with phenylarsine oxide and then incubated at 37 degrees C for 10 min exhibited a two- to threefold increase in surface receptor activity for macroglobulin.protease complexes, diferric transferrin, and mannose-terminal glycoproteins. Analysis of the concentration-dependence of ligand binding indicated that changes in ligand-binding activity were due to changes in receptor number rather than alterations in ligand-receptor affinity. Surface receptor number could also be increased by treatment of cells with three other sulfhydryl reagents, N-ethylmaleimide, p-chloromercurobenzoate, and iodoacetic acid. The increase in receptor activity was maximal after 10 min and decreased over the next hour. This decrease in cell-associated receptor activity was due to the release of large membrane vesicles which demonstrated a uniform buoyant density by isopycnic sucrose gradient centrifugation. Treatment of cells with phenylarsine oxide did not decrease the cellular content of lactate dehydrogenase or beta-galactosidase, indicating that cell integrity was maintained and lysosomal enzyme release did not occur. Our studies indicate that phenylarsine oxide treatment in the presence of extracellular Ca2+ results in the fusion of receptor-containing vesicles with the cell surface.

Animals↗
PubMed1985

Problems in classification of schizophrenics as neuroleptic responders and nonresponders.

The authors review the many clinical and pharmacological factors that affect neuroleptic response and complicate the classification of schizophrenic patients into responders and nonresponders. The subtyping of patients on the basis of "positive" or "negative" symptoms and the presence or absence of brain atrophy may be particularly useful in predicting neuroleptic response. There is also a promising relationship between plasma neuroleptic concentrations and response. The concept of supersensitivity psychosis is introduced as a reason for apparent nonresponse in some patients. In others, neuroleptic responsivity may be inherently variable. The authors make suggestions for future research in neuroleptic response.

Animals↗
PubMed1985

Bladder cancer after pelvic irradiation for cervical cancer.

Pelvic irradiation for gynecologic malignancy is associated with several late neoplastic and nonneoplastic complications in the irradiated field; however, this association has been infrequently recognized in primary care literature. We present two cases of bladder cancer that developed 16 and 19 years, respectively, after pelvic irradiation for cervical cancer. The frequent occurrence in older women of cystitis, hematuria, and nonspecific bowel and bladder symptoms of a benign origin obscures identification of late neoplastic complications after pelvic irradiation. Based on experimental and epidemiologic evidence, we believe cost-effective screening methods should be investigated to allow earlier detection of neoplasms; and, in the interim, a high index of suspicion for bladder cancer is warranted in this growing population of high-risk patients.

Adult↗
PubMed1985

Natural killer cell activity in multiple sclerosis and myasthenia gravis.

Because of the potential role of Natural Killer (NK) cells in viral immunity and immunoregulation, we have undertaken a study of NK activity of peripheral blood lymphocytes from both Multiple Sclerosis (MS) and Myasthenia Gravis (MG) patients, two chronic diseases in which a viral etiology and an induced autoregulatory abnormality are strongly implicated. No significant difference between the mean NK activity in MS patients and controls was observed. A difference was observed between the NK activity of female MG patients and female controls, but no difference was seen between male MG patients and controls.

Adult↗
PubMed1985

A subpopulation of allospecific cytotoxic T-cell precursors with phenotypic characteristics of natural killer cells.

We have proposed that natural killer (NK) cells are germ-line V-gene encoded prothymocytes specific for either self or non-self histocompatibility antigens. This hypothesis predicts that at least some precursors of allospecific cytotoxic T cells (allo-CTL) are NK cells. To test this we examined the effect of depleting NK cells and/or T cells (by complement lysis with anti-asialo GM1 and/or anti-Thy 1) on the development of allo-CTL induced during mixed lymphocyte culture (MLC). Removal of Thy 1+ cells from MLC responder populations prevented development of allo-CTL. This was partially reversed by addition of concanavalin A-conditioned medium (Con A-CM) to the MLC at day 0. Removal of asialo GM1+ cells eliminated NK activity measured at day 0, but failed to prevent development of allo-CTL of otherwise intact responder cells. However, removal of asialo GM1+ cells did prevent the Con A-CM dependent development of allo-CTL by responder cells depleted of Thy 1+ cells. These findings indicate that a subpopulation of allo-CTL precursors has the phenotypic characteristics of NK cells: absence or low density of Thy 1, and susceptibility to complement lysis by anti-asialo GM1.

Animals↗
PubMed1985

Natural killer cells inhibit outgrowth of autologous Epstein-Barr virus-infected B lymphocytes.

To determine whether natural killer (NK) cells are the cells responsible for inhibition of outgrowth of Epstein-Barr virus (EBV)-infected autologous B lymphocytes, NK-enriched or NK-depleted populations were prepared by Percoll density gradient fractionation and complement lysis depletion of cells reacting with NK-specific monoclonal antibody HNK-1. These cells were then examined in parallel for NK activity and inhibition of outgrowth. NK-enriched low density cells inhibited outgrowth whereas NK-depleted high density cells did not. Low density cells treated with monoclonal antibodies HNK-1 and DR plus complement had little NK activity and failed to inhibit EBV-induced outgrowth, whereas these same cells treated with monoclonal antibodies OKT3 and DR plus complement had strong NK activity and caused marked inhibition of outgrowth. These findings indicate that NK cells rather than mature T cells, monocytes, or B cells, are responsible for inhibition of EBV-induced B cell outgrowth.

Adult↗
PubMed1985

[Apropos of the molecular biology of Huntington's chorea].

The authors analyze some aspects of the two families published by Gusella and al. (linkage between H.D. gene and a RLPF) and underline the cases unable to be diagnosed because non-informative sibships. They emphasize the new ethics problems risen by the discovery of this linkage.

Adolescent↗
PubMed1985

[The place of prenatal diagnosis in genetic counseling (1982-1983)].

34.2% of couples seen during the years 1982 and 1983 for genetic counselling had some kind of familial anamnesis such as affected partner or relative or children. They could have benefit from prenatal diagnosis who would have been accurate informative twice on three times. Indications methods and accuracy are studied in consideration to the reason of referring and the level of the risk. Genetic counselling and prenatal diagnosis appear as preventive means adapted to each consultant. Otherwise systematic ultrasonography allows a true prevention from which 17.6% of the couples having give birth to affected children could have benefit.

Female↗
PubMed1985

Gait and balance in the elderly. Two functional capacities that link sensory and motor ability to falls.

Neuromuscular function, which underlies efficient gait and balance, deteriorates with age and disease. A review of the literature and of data from the current study suggests the presence of poor gait and balance in elderly individuals who have a history of multiple falls. The tests of gait and balance are simple to perform and therefore may be widely applicable in evaluating individuals at risk of falls. Quantitative studies of motor and sensory function, vibratory sensation, and electrophysiologic studies of nerve integrity are discussed. Deteriorating motor and sensory control mechanisms appear to play an important role in falling.

Accidents↗
PubMed1985

Decreased natural killer cell activity in patients with zinc deficiency with sickle cell disease.

Zinc deficiency is associated with depression of a number of immune responses. To assess the relationship of zinc and natural killer activity, we studied natural killer activity in adults with sickle cell disease and in two normal volunteers rendered zinc deficient by dietary restriction. Natural killer activity was significantly lower in patients with sickle cell disease and zinc deficiency (5.1 +/- 2.9 lytic units per 10(6) cells) than in controls (11.7 +/- 5.0 lytic units per 10(6) cells). In the two volunteers, natural killer activity declined during zinc restriction and returned to near initial levels with zinc repletion. These results suggest that zinc deficiency is associated with a lowering of natural killer activity.

Adult↗
PubMed1985

[Genetic counseling. Indications, problems and prospects].

From their personal experience, the authors demonstrate that, in spite of increased requests in general, couples in underprivileged socio-cultural classes are insufficiently concerned by genetic counselling; on the contrary it is too often requested by women who are already pregnant. They emphasize the necessity of providing information to all at risk couples and the essential part taken by family doctors. They discuss the difficulties of geneticists when consulters do not express a real question or wait to be given a rule of behaviour. Antenatal diagnosis (proposed to 2 of every 5 couples in 1983) changed the concept of genetic counselling by replacing a probability (the risk) by a certainty (the child presents with the disease or is normal). However, one should not look to either genetic counselling or antenatal diagnosis for a considerable decrease in the incidence of affected children.

Female↗
PubMed1984

Heme regulation of HeLa cell transferrin receptor number.

The number of diferic transferrin receptors on HeLa cells decreases when cells are grown in iron-supplemented media. The experiments reported here suggest that heme is the iron-containing compound which serves as the signal for receptor number regulation. When HeLa cells were grown in the presence of hemin, transferrin receptor number decreased to a greater degree than when cells were grown in equivalent amounts of iron supplied as ferric ammonium citrate. Incubation of cells in conditions which increased cellular heme content resulted in a decrease in cellular transferrin receptors. Incubating cells with 5-aminolevulinic acid (thus bypassing the rate-limiting step in heme biosynthesis, 5-aminolevulinic acid synthase) led to a decrease in transferrin receptor number. Incubation of cells with an inhibitor of heme oxygenase, Sn-protoporphyrin IX, also led to a decrease in transferrin receptor number. When cellular heme content was decreased by inhibiting heme synthesis with succinylacetone (an inhibitor of 5-aminolevulinic acid dehydratase), or by depriving cells of iron with deferoxamine, an increase in HeLa cell transferrin receptor number was seen. When HeLa cells were incubated with inducers of heme oxygenase (CoCl2, SnCl2, Co-protoporphyrin IX), transferrin receptor number also increased. The effects of all compounds which alter transferrin receptor number were dependent on the concentration of the supplement, as well as the duration of the supplementation. These experiments suggest that intracellular heme content may be an important signal controlling transferrin receptor number.

Aminolevulinic Acid↗
PubMed1984

Antibodies to the core protein of lymphadenopathy-associated virus (LAV) in patients with AIDS.

Lymphadenopathy-associated virus ( LAV ), a human T- lymphotrophic retrovirus isolated from a homosexual man with lymphadenopathy, has been causally associated with acquired immunodeficiency syndrome (AIDS). A sensitive and specific radioimmunoprecipitation test was developed for the detection of antibodies to the major core protein of LAV , p25 (molecular weight 25,000). Antibody to LAV p25 was found in the serum of 51 of 125 AIDS patients, 81 of 113 patients with lymphadenopathy syndrome, 0 of 70 workers at the Centers for Disease Control (some of whom had handled specimens from AIDS patients), and 0 of 189 random blood donors. Of a group of 100 homosexual men from San Francisco whose serum was obtained in 1978, only one had antibody to LAV p25; in contrast, of a group of 50 homosexual men in the same community whose serum was obtained in 1984, 12 had antibodies to LAV p25.

Acquired Immunodeficiency Syndrome↗
PubMed1984

Effects of social factors on adrenal weight and related physiology of Macaca fascicularis.

Increased adrenal cortical activity and hypertrophy of adrenal glands associated with defeat and social subordination have been reported frequently in small mammals; these adrenal changes have been linked to impairments in immune response, glucose metabolism and reproductive performance. Similar studies in primates have produced variable results. The current study was undertaken to illuminate the effects of social status on the adrenal gland and to examine concurrent effects of social variables on other physiological systems in Macaca fascicularis, in an initial exploration of the hypothesis that high and low social status have different physiological consequences. Sixty adult male M. fascicularis were housed in social groups of n = 5, under either stable or unstable social conditions. It was found that subordinate animals had heavier adrenal glands and somewhat higher plasma glucose concentrations than dominants. In contrast, dominants had higher blood pressure and worsened atherosclerosis, under some conditions, than subordinates. These data appear to offer preliminary support for Henry and Stephen's hypothesis of differential arousal of dominant and subordinate animals.

Adrenal Glands↗