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Biomedical subjects

J Levy

Publications and source records attributed to J Levy.

At least 325 records · Page 18Linked to original sources
PubMed1988

Gonadotropin-releasing hormone specific binding sites in uterine leiomyomata.

Gonadotropin-releasing hormone (GnRH) analogs can cause regression of uterine leiomyomata. This effect is thought to be mediated by the inhibition of gonadotropin release and steroid synthesis. In the present study we examined the possibility that these analogs may also act directly on uterine leiomyomata. Specific binding sites for GnRH are present in myoma membranes, as 125I-Buserelin binding was displaced with equal efficiency by the superagonists, Buserelin and D-Trp6-GnRH, and by the antagonist Organon 30276, but not by unrelated peptides such as thyrotropin releasing hormone and oxytocin. A nonlinear Scatchard curve obtained for Buserelin specific binding suggests the presence of at least two binding sites, one of which exhibits a relatively high affinity for GnRH analogs (Kd of approximately 10(-8) M). Western blotting with a specific GnRH receptor antibody revealed the presence of a 60 kDa protein in myoma membranes. This protein has a similar molecular weight to the purified pituitary GnRH receptor. These results indicate, for the first time, the presence of specific binding sites for GnRH in uterine leiomyomata, suggesting a direct effect of GnRH analogs on this tissue.

Adult↗
PubMed1988

Plasma membrane phospholipid content in non-insulin-dependent streptozotocin-diabetic rats--effect of insulin.

The activity of (Ca2+ +Mg2+)-ATPase is impaired in kidney basolateral membranes from non-insulin-dependent streptozotocin-diabetic rats. To study the possible role of changes in membrane phospholipid content in the malfunction of this enzyme in kidney membranes of the diabetic animals, phospholipid (phosphatidic acid, phosphatidylcholine, phosphatidylethanolamine, phosphatidylinositol, phosphatidylserine, and sphingomyelin) content was measured in kidney and liver membranes obtained from non-insulin-dependent diabetic rats. Total phospholipid content was similar in liver and kidney membranes of diabetic and control rats (595 +/- 47 versus 624 +/- 29 in liver and 469 +/- 22 versus 458 +/- 17 nmol Pi/mg protein in kidney respectively). Phosphatidylethanolamine content in kidney and liver membranes of diabetic rats was lower than in control rats (87.7 +/- 1.8 versus 96.4 +/- 2.2 nmol Pi/mg protein, p less than 0.01 and 87.1 +/- 3.7 versus 101.8 +/- 3.5, p less than 0.02 respectively). Phosphatidylinositol content was higher in kidney (28.0 +/- 0.6 versus 23.9 +/- 2.1, p less than 0.02) but not liver membranes from diabetic rats. The in vitro direct effect of insulin on the phospholipid content in kidney membranes was also measured. Physiologic concentrations of insulin (718 pmol/l for 30 min) increased the phosphatidic acid content in membranes from control but not from diabetic rats by 34.2% (p less than 0.02). This rise was readily measurable after 3 min of exposure to insulin.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1988

The emergence of hepatic fibrosis and portal hypertension in infants and children with autosomal recessive polycystic kidney disease. Initial and follow-up sonographic and radiographic findings.

Long-term imaging and clinical findings are reported in six children whose polycystic kidney disease was detected in infancy or early childhood. Over time (2 years to 20 years) all patients developed portal hypertension from hepatic fibrosis, a problem primarily noted in recessive pattern polycystic kidney disease. Mild renal failure (two patients) was accompanied by serious systemic hypertension in the same patients. In one family, one of the babies also showed dilated right hepatic ducts. Imaging studies included urography and CT although recently ultrasonography was the method of choice. The relative renal and hepatic manifestations in these patients so changed with time that it would seem fallacious to attempt to use rigid classifications based on findings at initial diagnosis.

Child, Preschool↗
PubMed1988

Rat epiphyseal cells in culture: responsiveness to bone-seeking hormones.

Cell cultures derived from young rat epiphyseal cartilage were grown for approximately 2 wk in BGJb medium supplemented with 10% fetal bovine serum to reach confluence. These cells were identified as chondrocytes as checked by morphology, the presence of alkaline phosphatase, and a positive type II collagen antibody reaction. The cells also responded to different hormonal treatment. Parathyroid hormone (PTH) increased cyclic AMP production by 50% within 15 min of treatment, whereas prostaglandin E2 (PGE2) caused an increase of 160%. Calcitonin (CT) did not affect cAMP production in these cells. DNA synthesis 24 h after hormonal treatment was increased by PTH (2.5-fold) and PGE2 (2-fold), but not by CT. Among the vitamin D metabolites, 24,25(OH)2D3 increased significantly the [3H]thymidine incorporation into DNA, whereas 1,25(OH)2D3 effect was minimal. These results provide evidence for the use of these cell cultures as a model for cartilage in vitro when studying biological and hormonal responsiveness.

24,25-Dihydroxyvitamin D 3↗
PubMed1988

Page kidney phenomenon in kidney allograft following peritransplant lymphocele.

A case of kidney allograft dysfunction in a recipient with a prior lymphocele is described. We attribute it to a Page kidney phenomenon caused by a constrictive pericapsular fibrosis. Surgical exploration and excision of the fibrotic tissue were followed by the recovery of renal transplant function. To our knowledge, only 1 case of Page kidney in renal allograft due to peritransplant hematoma has been described in the literature.

Adult↗
PubMed1988

Perceptual asymmetries in left- and right-handers for cartoon and real faces.

We examined 40 left-handers and 40 right-handers on two free-vision tests of face processing. A chimeric face composed of a smiling half-face joined to either a neutral half-face (real faces) or a sad half-face (cartoon faces) and its mirror image were presented on each trial. Subjects judged which chimeric face looked happier, the one with the smile to the left or the one with the smile to the right. Right-handers, but not left-handers, had a highly significant leftward attentional bias, since chimeras with the smile to the left were judged happier than those with the smile to the right. The cartoon- and real-face tasks did not differ in the mean perceptual asymmetries they elicited. However, correlations between attentional-asymmetry scores for the two tasks, although high for both left- and right-handers, were significantly smaller than task reliabilities. Thus, the cartoon- and real-face tasks overlap to a major extent in the lateralized processes they measure, but to a lesser extent, they also index different lateralized processes.

Adult↗
PubMed1988

Pregestational diabetes: insulin requirements throughout pregnancy.

The management of pregestational diabetes requires tight metabolic control to reduce maternal and perinatal morbidity and mortality. It has been suggested that type I diabetes is a disorder characterized by insulin deficiency and type II diabetes is characterized by insulin resistance; however, it may be hypothesized that a difference in insulin requirements should emerge throughout pregnancy to reflect the dissimilarities in these two metabolic disturbances. The current investigation of 103 women with pregestational diabetes used a novel approach (reflectance meters with onboard memories) to uncover the actual insulin dosages required to reach and maintain optimum metabolic control throughout pregnancy. It was found that both type I and type II diabetes appear to have a triphasic insulin pattern, with the patient having type II diabetes requiring significantly higher doses of insulin during each trimester. This seems to suggest that the hormonal changes in pregnancy may have a similar effect on both type I and type II diabetes but to a different degree. Thus this should be considered in the treatment of pregestational diabetes and in the development of an algorithm for diabetes management.

Adult↗
PubMed1988

Hypertension and diabetes.

Diabetes mellitus and hypertension are both common diseases, especially with an increasingly aged population. Hypertension accelerates the development of diabetic retinopathy, nephropathy, and peripheral vascular disease in the diabetic patient. Diabetes represents a type of premature aging and hypertension in the diabetic patient is characterized by many of the same pathophysiologic properties seen in the elderly hypertensive patient.

Antihypertensive Agents↗
PubMed1988

Pathogenesis of NIDDM--a disease of deficient insulin secretion.

Type 2 diabetes is a familial disease and studies of both Caucasian and Japanese families have raised the possibility that a major susceptibility gene is involved. The majority of patients have both beta cell dysfunction and impaired insulin sensitivity but studies of relatives of Type 2 diabetic patients suggest that beta cell dysfunction is an early feature of the disease. Impaired insulin sensitivity, from acromegaly, Cushing's disease or steroid therapy, induces diabetes only in a small proportion of the population, and they may be those who have an inherited cell defect. We postulate that a single beta cell defect gene, on its own, may be insufficient to cause overt diabetes and would lead to life-long glucose intolerance unless associated with other defects such as impaired insulin sensitivity. The nature of such a postulated beta cell defect is uncertain. Whilst it has been reported to be specific to glucose, and not to non-glucose stimuli, this feature may be secondary to hyperglycaemia. The occurrence of islet amyloid in 70-90% of Type 2 diabetic patients, and rarely in the normal population, raises the possibility that amyloid deposition causing disruption of the islet is a factor which might affect beta cell function. Amyloid formation may be a primary abnormality or could be secondary to beta cell dysfunction induced by hyperglycaemia. A major susceptibility gene might predispose a proportion, perhaps 10-15%, of a Caucasian population towards diabetes. The subsequent development of diabetes in a particular patient is likely to depend on many factors including other genetic factors, a sedentary life style and obesity. In different populations different genetic influences may operate, including abnormalities of insulin receptor genes and glucose transporter genes, which may allow a beta cell abnormality to become expressed clinically.

Diabetes Mellitus, Type 2↗
PubMed1988

Differential distribution of protein kinases along the crypt-to-lumen regions of rat colonic epithelium.

The activity of cAMP-dependent and cAMP-independent protein kinases, a class of enzymes involved in the regulation of cell proliferation was measured in rat colonic epithelium. Sequential cell populations harvested by a stepwise scraping technique from colonic crypt regions were identified by histology and incorporation of [3H]-thymidine into DNA. cAMP-independent phosphorylation of casein, in the presence of [gamma-32P]ATP, was markedly suppressed by quercetin, a bioflavonoid known to inhibit G-type casein kinase, protein kinase-C and tyrosine protein kinase. Conversely, the cyclic nucleotide regulatable form requiring histone as substrate was responsive to the action of the heat stable protein kinase inhibitor. The protein kinase species were characterised and partially purified by DEAE-cellulose chromatography. The activity of cAMP-dependent protein kinase in colonic cytosols (pmol 32P/min/mg protein, means (SE)) increased from 129.4 (15.9) in superficial cell populations to 238.5 (31.4) in lower crypt cell fractions (p less than 0.01). Colonic cAMP-independent protein kinase activity increased from 87.3 (15.6) in surface cell preparations to 178.1 (30.0) in lower crypt cell populations (p less than 0.02). A comparable activity gradient was observed in membrane fractions. The activity gradient persisted when the results were expressed as a function of cellular DNA. These findings indicate that protein kinases display a defined topological segregation along the colonic crypt regions and that during migration to the lumen colonic cells attenuate enzyme signals supposedly related to tissue growth.

Animals↗
PubMed1988

Binding of mouse red blood cells (MRBC) by human thymocytes: augmentation of rosette formation by phospholipase C treatment.

The formation of rosettes with MRBC is not an exclusive property of chronic lymphocytic leukemia cells and of human B-lymphocytes. Human thymus cells and the HD-MAR T-cell line were also found to be capable of forming rosettes with MRBC. The binding of MRBC by thymocytes differed from that of sheep (SRBC), rabbit (RRBC) and human (HRBC) erythrocytes by a number of parameters: monoclonal antibodies against the E-receptor inhibited the attachment of SRBC, RRBC, and HRBC, but not of MRBC to thymus cells. The presence of EDTA had the opposite effect, abrogating only the attachment of MRBC to thymus cells but not of RBC from the other sources. Exposure of thymus cells to pronase eliminated their capacity to bind SRBC, RRBC, and HRBC, but only slightly inhibited the attachment of MRBC. Treatment with Vibrio cholerae neuraminidase enhanced the formation of rosettes with SRBC, RRBC, and HRBC, but had no effect on the formation of rosettes with MRBC. Exposure of thymus cells and of the HD-MAR cells to phospholipase C enhanced the proportion of rosettes formed with MRBC, but had no effect on the binding of other RBC. Treatment with either phospholipase A2 or phospholipase D had no such effect. The binding of MRBC by Raji cells was not increased by phospholipase C treatment. The present study indicates that the binding of MRBC by human thymus cells is mediated by receptors distinct from those involved in the binding of SRBC, RRBC, and HRBC and also from those mediating the binding of MRBC to human B-cells.

Animals↗
PubMed1988

The effect of different LH-RH agonists on the levels of immunoreactive gonadotropins.

The present study compared the effect of D-Ser(tBU)6-des-Gly-LHRH-ethylamide in the form of a nasal spray, D-Trp6-LHRH, which is applied in daily intramuscular injections, and the long-acting preparation, D-Trp6-LHRH, which is given as a monthly intramuscular injection, on the function of the pituitary-ovarian axis. Forty spontaneously menstruating women not belonging to the PCOD group participated in the study, the results of which indicate that the three LH-RH agonists used are similarly effective in their ability to down-regulate the pituitary-ovarian axis. The time required for the appearance of the suppressive effect, as measured by reduced levels of gonadotropins and estradiol as well as by the abolishment of the hypophyseal response to rising estrogens, usually does not exceed 14 days and is never more than 28 days. The immunoreactive LH-reducing effect of the LH-RH agonists was true only if the basic levels of the hormone were higher than 11 mIU/ml. This fact might be particularly significant in patients with polycystic ovarian disease or in perimenopausal women.

Buserelin↗