Biomedical subjects
J Levy
Publications and source records attributed to J Levy.
Implication of the Thy-1 antigen on mouse thymus cells in the recognition of 'self' structures.
Thymus cells of mice form rosettes with autologous and allogeneic erythrocytes. The nature of the thymus cell receptors which mediate the binding of erythrocytes is not known. The aim of the present study was to determine the effect of various antisera to T-cell specific antigens on the formation of rosettes by mouse thymus cells. In all strains of mice tested, the exposure of thymus cells to rabbit anti-mouse brain serum (RABR) was found to inhibit autorosette formation. Similarly, monoclonal Thy-1 antibodies inhibited the formation of autorosettes by thymus cells in all strains tested. Monoclonal antibodies against Lyt-1, Lyt-2, and TL determinants had no such effect. Monoclonal Thy-1 antibodies inhibited the formation of rosettes with allogeneic erythrocytes only when the thymus contained the Lyt-2.2 allele (BALB/c, C57BL), but not when it contained the Lyt-2.1 allele (AKR/J, C3H, DBA/2). These results indicate that Thy-1 determinants on thymus cells are involved in the recognition of 'self' structures, shared by erythrocytes of all strains of mice. Lyt-2 determinants may play a role in the recognition of 'non-self', allogeneic determinants, but the thymus cell surface structures encoded by the two Lyt-2 alleles may differ in their affinity to allogeneic erythrocytes.
Calcitriol-resistant rickets with alopecia.
Four children of two kindred had alopecia associated with severe rickets, resistant to treatment, and caused by defective cytoplasmic and nuclear receptors for the active vitamin D metabolite calcitriol (1,25-dihydroxyvitamin D3). Scalp biopsy specimen revealed a normal number and light microscopic features of the hair and hair follicles. Calcitriol-resistant rickets should be added to the list of inherited disorders of hair growth, and the association of rickets with alopecia needs to be considered in the differential diagnosis of hair loss.
Possible involvement of phosphoinositide phosphorylation and tyrosine kinase activity in the growth control of rat mammary tumors.
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Hemoptysis and anemia in a 3-year-old boy.
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Professional management.
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Intrathymic parathyroid adenoma in a child.
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[Value and limitations of prenatal microbiological surveillance].
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Testicular feminization syndrome. An unusual case with high estrogen levels.
In an unusual case of testicular feminization, the patient had a high estrogen and low testosterone level. The source of this female hormone excess may have been functioning gonadal stroma of either female or male derivation. All other aspects of the case were consistent with classic examples of the syndrome.
Blood level of C3 complement component as an aid in the management of acute phase glomerulonephritis.
Ninety-five patients with acute glomerulonephritis, based upon clearly defined pathological criteria, were studied and scored. The scoring was correlated to their levels of blood complement components. Patients with low C3 serum levels had a severe course during the acute phase of their disease, as compared with those with normal C3 serum levels. No such correlation was established with regard to C4 serum levels. It is suggested that C3 serum level may serve as an indicator of the expected severity of the inflammatory process and thus as an aid in the management of patients with acute glomerulonephritis in the initial phase of the disease.
[Local edema as the presenting symptom in Schoenlein-Henoch purpura].
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DC hospital aids local community in securing bus route for residents.
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Tyrosine protein kinase activity in the DMBA-induced rat mammary tumor: inhibition by quercetin.
Tyrosine protein kinase activity was measured in membranes from DMBA-induced mammary tumors, with Angiotensin II as substrate. The apparent Km for the peptide was 3.3 mM. This enzymatic activity is inhibited by Ca+2; Mn+2 can replace Mg+2 with an increase in the Km for ATP from 47 /microM to 172 microM. The enzymatic activity was not affected by cyclic AMP but was inhibited in dose dependent manner by quercetin, a bioflavonoid which is known to inhibit proliferation of malignant cells in vitro.
[Partial splenectomy with the automatic stapler in the adult].
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Immunofluorescent antigluten antibody test. Titer and profile of gluten antibodies in celiac disease.
Circulating antibodies to gluten fractions have been detected in most patients with celiac disease during gluten ingestion. The various detection techniques, however, are rather complex and inadequate for routine clinical use. Recently, a new indirect immunofluorescent method, named the antigluten antibody (AGA) test, has been developed. To establish the reliability of the test we compared six groups of patients: (1) 15 patients with biopsy-proved celiac disease of whom 13 had positive test results (the other two had already been receiving a gluten-free diet for two to three weeks); (2) 13 malnourished patients without celiac disease who had damaged mucosa, of whom only two had positive test results; (3) 21 patients with celiac symptomatology but normal mucosa, of whom four had positive test results; (4) 42 patients with other intestinal tract diseases, of whom seven had positive test results; (5) 28 patients with extraintestinal diseases, of whom only two had positive test results; and (6) 26 patients with autoimmune diseases, of whom five had positive test results. All patients with celiac disease who had positive test results and who were receiving a gluten-containing diet had titers of 1:40 to 1:80 in the IgG class, while all other patients with positive AGA test results had a low titer of 1:10 to 1:40, in the IgM class mainly. We conclude that the AGA test is an effective screening tool for patients with celiac disease and may serve as a practical index of dietary gluten avoidance.
Time-dependent inhibition of insulin release: suppression of the arginine effect by hyperglycaemia.
Brief stimulation of the pancreas with arginine causes a refractory state which reduces the insulin response to subsequent stimulations (time-dependent inhibition). In control subjects, a pair of arginine injections (75 mg/kg) at a 30-min interval resulted in 20% reduction of peak and integrated insulin responses to the second injection. In Type 2 (non-insulin-dependent) diabetic patients and in obese subjects, the inhibitory effect of repeated arginine stimuli was abolished. Healthy subjects were made acutely hyperglycaemic (9.3 +/- 0.3 mmol/l) by the glucose clamp technique. This induced a three- to fivefold greater insulin response to arginine. Compared to the response of diabetic subjects with similar hyperglycaemia, the control subjects secreted four to nine times more insulin. When the arginine stimulation was repeated 30 min later, no inhibition was observed, the second insulin response being instead augmented 1.5- to 1.8-fold. We conclude that (1) the insulin response to arginine is markedly reduced in Type 2 diabetes; (2) arginine-induced time-dependent inhibition of insulin release is abolished in patients with minimal to moderate hyperglycaemia; (3) this is probably due to the acute synergistic action of glucose and arginine on the B cell; (4) time-dependent inhibition of insulin release may be a protective mechanism against insulin oversecretion following repetitive stimulation of the pancreas; its abolition in hyperglycaemic states may be a compensatory mechanism, allowing substantial increases in insulin output.
1,25-Dihydroxyvitamin D resistance, rickets, and alopecia.
Two unrelated kindreds with four affected children having 1,25-dihydroxyvitamin D resistance, rickets, and alopecia are described. The children exhibited early onset of severe rickets with hypocalcemia, hypophosphatemia, elevated serum alkaline phosphatase levels, and secondary hyperparathyroidism. Radiography showed diffuse demineralization and classic changes of rickets. All affected children had total-body alopecia. Serum levels of 1,25-dihydroxyvitamin D3 were elevated and rose to extremely high values during treatment, with no apparent change in the mineral disorder. However, secondary hyperparathyroidism and hypophosphatemia did remit during treatment despite persistently low calcium levels. Skin biopsy was performed in the parents and affected children in one kindred. Analysis of 1,25-dihydroxyvitamin D3 receptors in cultured fibroblasts indicated apparent normal receptors in the parents and undetectable receptors in both affected children. After long periods of treatment with vitamin D metabolites and mineral replacement, healing took place in the older child in each kindred. These data suggest that the healing occurred spontaneously as the children reached seven to nine years of age rather than as a result of the treatment. The biochemical lesion in these children appeared to be a genetically transmitted defect in the 1,25-dihydroxyvitamin D3 receptor. The mechanisms by which healing was initiated and maintained remain to be elucidated.
Can a reaction time paradigm simultaneously index arm position effects, spatial compatibility effects, and neural pathway effects? Comments on Bradshaw, Nettleton and Spehr.
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