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Biomedical subjects

S Varma

Publications and source records attributed to S Varma.

At least 163 records · Page 9Linked to original sources
PubMed1992

Human thymocytes secrete luteinizing hormone: an autocrine regulator of T-cell proliferation.

There is evidence that there may be bidirectional communication between immune and gonadotropin producing cells. In the present study we describe the secretion and function of an LH like peptide secreted from the human thymus. Serial dilutions of thymic extracts obtained from surgically removed thymic tissues displaced I125 LH from LH antiserum parallel to that produced by pituitary LH. Thymic LH was detected as early as 10 days of age and maximal concentrations were noted at 5 months. Utilizing a sensitive and specific hormonal enzyme linked immunoplaque assay developed in our laboratory, we were able to detect LH secretion from unstimulated human thymocytes. Neutralizing endogenously released LH in PHA stimulated thymocytes with LH antiserum significantly inhibited thymidine incorporation. We conclude that an LH-like peptide is secreted by human thymocytes which acts as an autocrine co-mitogen in lymphoproliferation.

Cell Division↗
PubMed1992

Prolactin synthesized and secreted by human peripheral blood mononuclear cells: an autocrine growth factor for lymphoproliferation.

Prolactin has been shown to have an immunoregulatory role in the rodent immune response. A prolactin-like molecule has also been found in mouse splenocytes and a human B-lymphoblastoid cell line. We have evaluated whether human peripheral blood mononuclear cells (PBMCs) synthesize and/or secrete prolactin. We used the polymerase chain reaction (PCR) to generate a 276-base-pair prolactin product from human PBMCs, and Southern blot analysis confirmed that it was related to prolactin. Western blotting using a polyclonal antibody to prolactin indicated that cell extracts prepared from human PBMCs contained a high molecular mass (60-kDa) immunoreactive prolactin. To determine whether this PBMC prolactin was being secreted, we developed a highly sensitive and specific hormonal enzyme-linked immunoplaque assay. With this assay, we were able to detect human prolactin secretion from concanavalin A (Con A)- or phytohemagglutinin-stimulated PBMCs but not from unstimulated PBMCs. We next sought to determine whether this secreted prolactin could function as an autocrine growth factor in lymphoproliferation. We observed that anti-human prolactin antiserum significantly inhibited human PBMC proliferation in response to Con A or phytohemagglutinin. We conclude that a prolactin-like molecule is synthesized and secreted by human PBMCs and that it functions in an autocrine manner as a growth factor for lymphoproliferation.

Base Sequence↗
PubMed1992

An analysis of resuscitative requirements of petrol (gasoline) burns.

A retrospective study was carried out to confirm the clinical impression that petrol (gasoline) burns had a greater resuscitation requirement than other types of thermal injury. A total of 450 admissions to the St Andrews Hospital Regional Burn Unit from 1982 to 1988 were reviewed. Patients with pre-existing cardiovascular disease, respiratory disease, inhalation injury and fatalities occurring within the first 72 h of admission were excluded from the study. Forty-four patients met all requirements for inclusion within the study. These 44 patients consisted of 15 with petrol burns and 29 with non-petrol burns, all of whom were resuscitated using the modified Muir and Barclay formula, with adjustments made on the basis of clinical and laboratory monitoring. Comparison of resuscitation requirements of the two groups by the Wilcoxon Rank Sum Test showed that the petrol burns group had a significantly greater fluid resuscitation requirement (P less than 0.01).

Adolescent↗
PubMed1992

Extrathoracic Castleman's disease.

Castleman's disease is an uncommon clinical entity. We report two cases of this disease with a brief review of literature. Both of them had extrathoracic disease which is relatively infrequent. One of them presented with localized hyaline vascular type of the disease and the other with the multicentric plasmacytic variety. The patient with the latter form of Castleman's disease had sclerodactyly, which has not been reported earlier in association with this disease.

Adolescent↗
PubMed1991

Prolonged, pregnancy-related pure red cell aplasia; a case report.

We describe the clinical course of a patient with pregnancy-related, acquired, pure red cell aplasia (PRCA). The course of PRCA was prolonged and ultimately responded only to corticosteroids. It did not recurr over 4 years of observation despite another gestation, and no other cause for PRCA could be detected during this long period.

Adrenal Cortex Hormones↗
PubMed1991

A clinico-pathological study of six cases of hairy cell leukaemia.

Clinicopathological findings of six cases of Hairy cell leukaemia are presented. All the patients were males, the age ranged between 32-57 years. Complications of anaemia and neutropenia were common modes of presentation. Hepatomegaly and splenomegaly were present in all the cases whereas only 2 patients had lymphadenopathy. Severe pancytopenia was detected in 3 cases and circulating hairy cells were present in all the cases. Trephine biopsy done in all six patients was found to be diagnostic. Tartrate resistant acid phosphatase was detected in the hairy cells of 2 cases.

Adult↗
PubMed1991

Neutrophil oxygen free radical production proportionates with the degree of myocardial ischemia.

OBJECTIVE: To assess the production of oxygen free radicals by chemiluminescence and to assess leukocyte aggregation, in patients with acute myocardial infarction and angina pectoris, and to compare these to creatine kinase-MB levels. DESIGN: Prospective study with serial estimation at presentation and 72 h later. SETTING: Referral, tertiary care hospital. PATIENTS: Group 1, acute myocardial infarction (n = 18); group 2, stable angina pectoris (n = 8); and age-and sex-matched normal healthy persons (n = 12). All patients included had pain of less than 24 h duration with typical electrocardiographic and laboratory abnormalities. Patients or controls who had any inflammatory disease in the preceding two weeks or who were on anti-inflammatory drugs, calcium channel or beta-adrenoceptor blockers, were excluded. TESTS: Venous blood samples taken at presentation and 72 h later were analyzed for creatine kinase-MB using a standard kit, neutrophilic chemiluminescence and leukocyte aggregation. MAIN RESULTS: In group 1 there were significant rises in both creatine kinase-MB and chemiluminescence, which subsequently regressed (P less than 0.02). There was, however, no statistical correlation between the two. The qualitative pattern of the rise and fall of chemiluminescence was similar in group 2. Changes in leukergy in both groups were not significant. CONCLUSIONS: Oxygen free radical generation occurs early in myocardial ischemia with regression by 72 h. Neutrophilic chemiluminescence may provide an alternative method for assessment of myocardial ischemia.

Cell Aggregation↗
PubMed1989

Cloning and nucleotide sequence of ovine prolactin cDNA.

A cDNA expression library was constructed in the lambda gt 11 phage vector using ovine (o) pituitary mRNA. The clone, pOP1, carrying a 934-bp insert contains an open reading frame beginning with the first nucleotide (nt) and ending with the stop codon TAA at nt position 781. Two potential translation start codons (ATGs) are present in the 5' region of this cDNA. Translation initiation could occur at the 5' proximal ATG at nt position 61. The nucleotide sequence around this ATG (TCCATGG), resembles the optimum sequence context for translation initiation by the eukaryotic ribosomes, as defined by mutational analysis [Kozak, Cell 44 (1986) 283-292)], with its substitution of the A at -3 of the consensus sequence by a T residue in this clone. Translation initiated at this codon could potentially code for the entire pre-prolactin (pre-PRL) molecule. The 3'-untranslated region is 154 nt long and contains a polyadenylation signal AATAAA. The deduced amino acid sequence agrees in totality with the published amino acid sequence of the mature hormone. The present study reports on the nucleotide sequence of o-PRL mRNA and the deduced amino acid sequence in the signal peptide of the hormone.

Amino Acid Sequence↗
PubMed1989

Pancytopenia in nutritional megaloblastic anaemia. A study from north-west India.

We have analysed 139 consecutive cases (71 males and 68 females) of nutritional megaloblastic anaemia over a period of four and a half years. The majority of these patients belonged to the low socio-economic class and many of them were strict vegetarians. Sixty one percent were in the second and third decades of life. At the time of presentation, 46% had mild hepatomegaly, 42% fever, 34% mild splenomegaly and 20% bleeding manifestations. Of 102 cases in whom the biochemical parameters were available, vitamin B12 deficiency was detected in 76%, folate deficiency in 6.8%, combined B12 and folate deficiency in 8.8%; the remaining 7.8% had normal vitamin levels at presentation. All 139 patients had severe anaemia, 80.5% had thrombocytopenia and 43.8% had neutropenia as well as thrombocytopenia. It appears that during progression (in terms of duration) of megaloblastosis, anaemia is followed by thrombocytopenia and then neutropenia. Infection and bleeding in these patients may be aggravated by impaired functions of neutrophils and platelets, respectively.

Adolescent↗
PubMed1988

The effect of cyclosporin A on the growth and prolactin binding to Nb-2 rat lymphoma cells.

Cyclosporin A, an immunosuppressive agent, inhibited the prolactin stimulated growth of rat lymphoma Nb-2 cells. In the presence of 1 ng/ml of prolactin, 50% inhibition of growth was at 5 x 10(-6) M and the inhibition was reversible. The Kd of cyclosporin A binding to the Nb-2 cells was 10(-7) M and was independent of prolactin. The Kd of prolactin binding to the Nb-2 cells was 2 x 10(-10) M. Cyclosporin A did not influence the binding of prolactin to the cells and vice versa. The inhibitory effect of cyclosporin A on the growth of Nb-2 cells is due to some step other than the binding of prolactin to the cells.

Animals↗
PubMed1987

Regulation of expression of c-fos and c-myc in rat lymphoma Nb-2 cells.

This study examined the effects of the mitogen, prolactin and the cell cycle inhibitors, cyclosporin A and neomycin sulfate, on expression of the proto-oncogenes c-fos and c-myc in the rat lymphoma Nb-2 cell line. Stimulation of quiescent cultures with prolactin resulted in a 2-3-fold increase in the constitutive levels of c-myc mRNA which peaked at 4 h and declined thereafter. c-Fos mRNA was not detected in quiescent or prolactin-stimulated cultures. Cyclosporin A or neomycin sulfate reversibly blocked the mitogenic effect of prolactin on Nb-2 cells, but had little effect on constitutive levels of c-myc. However, the release of Nb-2 cells from a cyclosporin A or a neomycin sulfate block resulted in a rapid transient induction of c-fos which peaked at 0.5-1 h and declined rapidly thereafter. These results indicate that the rapid transient expression of c-fos following release from cell cycle blockage was not sufficient to elicit cell division, but these cells were competent to respond to prolactin. Prolactin allows progression through the cell cycle and enhances c-myc mRNA levels.

Animals↗