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M Gupta

Publications and source records attributed to M Gupta.

At least 217 records · Page 12Linked to original sources
PubMed1996

The role of the near upstream sequence in hypoxia-induced expression of the erythropoietin gene.

Transcription of the erythropoietin (epo) gene is regulated in response to tissue hypoxia. In this study we show that constructs containing 117 bp of the epo promoter sequence cloned upstream of a luciferase reporter, respond to hypoxia when transfected into the human hepatoma cell line, Hep3B. The sequence -61 to -45 (EP17) relative to the transcription start of the murine epo gene imparted an approximately 4-fold induction of reporter gene expression due to hypoxia. Internal deletion of EP17 resulted in loss of induction by hypoxia without altering basal expression of the 117 bp epo promoter reporter construct. Mutagenesis studies showed that the bases at positions -53, -59, from -49 to -51 and from -55 to -57 are essential for hypoxic induction. The EP17 sequence is required for the 3' enhancer element of the epo gene to be maximally functional. Gel shift and UV cross-linking experiments showed the presence in Hep3B nuclear extracts, of two protein factors with approximate molecular weights of 52 kDa and 25 kDa that bind to EP17. Introduction of specific mutations in the EP17 region that abolish induction by hypoxia, also eliminated the binding of one or both of these factors. These experiments demonstrate a role for the proximal region of the epo promoter in hypoxic induction of the epo gene.

Animals↗
PubMed1996

Lack of reproducibility in pregnancy of Korotkoff phase IV as measured by mercury sphygmomanometry.

BACKGROUND: Since hypertensive disorders of pregnancy are common, blood pressure is frequently measured in all pregnant women. Many authorities recommend that Korotkoff phase IV (K4, muffling of sound) is taken as the diastolic identification point measured on mercury sphygmomanometry in pregnancy because of reports that phase V (K5, disappearance of sound) is at or near to zero cuff pressure in some pregnant women. We compared the identification and reproducibility of K4 and K5 by observers unaware of each other's results. METHODS: In the first part of the study, two pairs of observers each took 340 measurements in 85 pregnant women. The second part of the study consisted of 1120 measurements in 80 pregnant and 80 non-pregnant women by five pairs of observers. Measurements were taken simultaneously by sphygmomanometry with a shared cuff and diaphragm; the observers were in separate booths. FINDINGS: K5 was identified in all measurements by both observers and never approached zero. K4 was heard in only 52% of measurements; in 33% of cases it was heard by only one of the pair of observers, so the pair agreed on its detection in only 19% of readings. Visual analogue scores used to assess Korotkoff sound quality indicated that systolic blood pressure was perceived significantly more clearly than diastolic blood pressure (K4 or K5). Even when K4 was heard by both observers, agreement on its value was poor (78% within 5 mm Hg vs 86% for K5, p < 0.05). K4 was heard significantly less often in non-pregnant women (32% of measurements). There was also no consistency in the identification of K4 within individual women. INTERPRETATION: K4 has little value in clinical management because it cannot be reproduced accurately. We recommend that K4 should be replaced by K5 as the measure of diastolic blood pressure in pregnancy.

Blood Pressure↗
PubMed1996

The effect of prior in vitro exposure of donor cells to trophic factors in neurotransplantation.

The ability of PC12 cells to regenerate processes is substantially enhanced in vitro if they have been previously exposed to nerve growth factor (NGF-primed), compared to cells that have not been exposed (NGF-naive). These studies were carried out to determine if the enhanced neuritogenic ability of NGF-primed cells is retained following transplantation. NGF-naive or NGF-primed PC12 cells were transplanted into the striatum of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-treated mice and allowed to survive for 2 weeks. Mice were given daily injections of cyclosporin A (CyA) to prevent anti-species graft rejection. The transplanted PC12 cells were visualized by tyrosine hydroxylase immunoreactivity. The NGF-naive transplanted cells formed dense clusters and large tumor masses in more than half the animals. Only a few of the naive PC12 cells had short processes. In contrast, many of the transplanted NGF-primed PC12 cells had processes. Furthermore, fewer of the animals transplanted with primed cells produced tumor masses in the striatum compared to animals that received NGF-naive cells. Transplantation of NGF-naive PC12 cells leads to a significant increase in the number of dopaminergic neurons in the host substantia nigra (SN) compared to MPTP-treated animals. The increase of host dopaminergic neurons was not statistically significant when NGF-primed PC12 cells were used. Following MPTP treatment and PC12 cell transplantation, injection of CyA did not affect the dopaminergic neurons in the host SN. These data suggest that exposure of cells to trophic factors, prior to transplantation, can enhance their level of differentiation and integration into the host brain.

1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine↗
PubMed1996

The kerosene tragedy of 1994, an unusual epidemic of burns: epidemiological aspects and management of patients.

An unusual and perhaps the first epidemic of burns occurred between 15 February 1994 and mid April 1994 in four districts of the State of Rajasthan in India. The cause of this epidemic was the accidental mixing of petrol in kerosene oil which was inadvertently overlooked. This mixture of kerosene and petrol was used mainly by people of low-income groups for lighting lamps. Most of the accidents occurred while pouring this highly inflammable petrol-kerosene mixture into ignited lamps. A total of 303 cases were reported: 118 of these patients sustained severe burns of whom 37 died. Small numbers of fresh cases kept occurring over a period of 2 months in spite of all efforts by the administration, because poor people kept using the fatal mixture due to ignorance and illiteracy. Most of the patients were managed at district hospitals with the help of plastic surgeons called for the purpose from Jaipur, the capital city of the affected State. A total of 40 out of 303 patients were transferred to SMS Hospital where a medical ward was vacated to manage these patients, as the 10-bed burn unit already had 300 per cent best occupancy. Most of these patients were not willing to be sent to a burn unit situated far away from their homes, but they had to be transferred because the general surgeons working at district hospitals were hesitant to manage them, not so much due to lack of training in the management of burns, but more due to lack of willingness to manage burns. This indicates the need for renewed emphasis not only of the necessity of training general surgeons, nursing and paramedical staff at district level in the management of burns, but also of the need to manage these cases at district level. This idea needs serious consideration and sincere efforts to implement it at the national level. The paper has been split into two parts: epidemiological aspects and management of patients.

Accidents, Home↗
PubMed1996

Chronic endotoxemia and endothelium-dependent vasodilation in coronary arteries.

Endotoxin acutely decreases the production of nitric oxide, leading to abnormal regulation of coronary vascular tone: however, the effects of chronic endotoxemia on vasomotion are unknown. We therefore tested the hypothesis that chronic, low-level endotoxemia inhibits endothelium-dependent vasodilation. Rabbits were continuously infused with a subclinical dose of Escherichia coli endotoxin (.6 microgram/24 h, intraperitoneal) or saline for 5 wk. Endotoxin at this concentration elicited no significant sustained pyretic or hemodynamic responses. Both endothelium-dependent and independent vasomotor responses were determined in coronary arteries (250-500 mu). Vasorelaxation in response to acetylcholine, but no adenosine diphosphate (ADP), was significantly enhanced in endotoxin-challenged animals (EC50 = 62.6 +/- 11.1 nM, control vs. 33.97 +/- 5.7 nM, endotoxin-challenged; p < .05). Vasoconstriction to PGF2 alpha, but not KCl, was significantly decreased in endotoxin-challenged animals. These results indicate that endothelium-dependent and independent vasomotor responses are altered during chronic endotoxemia and are due, in part, to alterations in signal-transduction mechanisms specific for certain types of receptors.

Acetylcholine↗
PubMed1996

Human immunoglobulin G autoantibodies to the thyrotropin receptor from Epstein-Barr virus-transformed B lymphocytes: characterization by immunoprecipitation with recombinant antigen and biological activity.

The TSH receptor (TSH-R) is the target antigen for disease-related autoantibodies in Graves' disease and primary myxoedema, but the repertoire of the antibodies or the nature of the precise antigenic epitopes is not known. We have immortalized peripheral blood B cells from six different autoimmune thyroid disease patients with Epstein-Barr virus and selected IgG-producing B cells by magnetic selection on anti-IgG-coated beads. Purified recombinant insect cell-derived extracellular region of TSH-R was used to identify the positive wells for expansion in culture. Stable B cell lines (n = 11) were obtained, which after limiting dilution led to two stable B cell clones. B cell lines and clones secreted IgG antibody that were shown to react biochemically with metabolically labeled or in vitro translated, nascent extracellular region of TSH-R, giving strong, confirmatory evidence of the presence of anti-TSH-R antibody. Supernatants from lines contained thyroid-stimulating activity, thyroid-blocking activity (as assessed by inhibition of TSH-mediated cAMP stimulation), or both of these activities. Interestingly, antibodies with stimulating activity were generated from a primary myxoedema patient, and antibodies of blocking specificities were obtained from newly diagnosed thyrotoxic Graves' disease patients. Our results favor a fine balance between stimulating and blocking autoantibody activities in determining the clinical presentation observed in patients with autoimmune thyroid disease patients who have these antibodies present in their serum.

Antigens↗
PubMed1996

Blood mercury in workers exposed to the preparation of mercury cadmium telluride layers on cadmium telluride base.

Study was conducted in a group of 32 persons engaged in liquid phase epitaxial growth of mercury cadmium telluride (MCT) layers for nearly 11 years. Airborne mercury concentrations in work environment have been exceeding the threshold limit value of 0.05 mg/m3 recommended by ACGIHD. Hg concentration in workplace during peak working hours remained between 0.04-0.08 mg/m3. Findings were compared with 32 unexposed referents. Mercury value was estimated 1.60 +/- 0.20 (mean +/- SD) in control, and in Phase I and II, 10.72 +/- 1.34 ng Hg/ml and 8.08 +/- 1.15 ng Hg/ml of blood respectively. Results indicate a fall in blood mercury level during the second phase of study. But the values did not return to normal even after a gap of 3 months. An individual who met with a mercury accident showed 226 ng Hg/ml of blood which decreased to 25 ng/ml after 3 months. It is inferred from the present study that Hg level has increased significantly in MCT workers during working period, and also in non-working period, the values were higher than controls.

Accidents, Occupational↗