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Biomedical subjects

R Kumar

Publications and source records attributed to R Kumar.

1,778 records · Page 99Linked to original sources

Predischarge dobutamine induced distant wall motion abnormalities after acute myocardial infarction predict multivessel disease.

Presence of multivessel coronary artery disease (MVD) identifies a high risk subgroup after acute myocardial infarction (AMI). Dobutamine stress echocardiography (DSE) has recently emerged as a promising non invasive test to detect the presence and extent of coronary artery disease. Forty six consecutive patients (38 males, 8 females; mean age 48.6 +/- 10.4 years) of Q-wave acute myocardial infarction were subjected to submaximal treadmill test (TMT) and dobutamine stress echocardiography to see their ability to predict multivessel coronary artery disease as detected by coronary angiography before hospital discharge. Dobutamine infusion was started at 5 micrograms/kg/min to a maximum of 40 micrograms/kg/min, to achieve 70 percent of the age predicted heart rate. Appearance of new regional wall motion abnormality was interpreted as positive DSE for MVD. Mean peak infusion dose of dobutamine used in the study was 28.56 +/- 5.67 micrograms/kg/min. In none of the patients, the test had to be terminated due to side effects. The sensitivity and specificity of DSE to predict MVD was 80 percent and 93.7 percent, respectively as compared to 45 percent and 86 percent for submaximal TMT. Thus, DSE in patients of AMI before hospital discharge is a safe procedure with fairly accurate prediction of multivessel coronary artery disease.

Adult↗

Growth inhibition of breast cancer cell lines by combinations of anti-P185HER2 monoclonal antibody and cytokines.

The p185HER2 oncogene is associated with poor prognosis in patients with breast cancer. Both anti-p185HER2 MAb and cytokines have been shown to downregulate p185HER2 expression. We investigated the effect of combinations of humanized 4D5, and anti-p185HER2 MAB, and the cytokines IFN-alpha, IFN-gamma or TNF-alpha on the growth of three p185HER2 positive human abreast carcinoma cell lines, SK-BR-3, BT-474, and MDA-MB-453. All three cell lines were treated with IFN-alpha (1000 U/ml) or IFN-gamma (1000 U/ml) or TNF-alpha (100 U/ml) with or without huMAb 4D5 (100 microM), and cell growth was determined on days 3-7. While IFN-alpha, IFN-gamma, TNF-alpha, and huMAb 4D5 all inhibited growth, an apparently additive inhibitory effect occurred using combinations of huMAb 4D5 plus cytokine, with huMAb 4D5 plus TNF-alpha causing the greatest growth inhibition. These results demonstrate the potentiation of growth inhibition of breast cancer cell lines by the combination of anti p185HER2 MAb and cytokines, and suggest that combinations of anti-growth factor receptor MAb and cytokines may be useful in the treatment of breast cancer.

Antibodies, Monoclonal↗

Mechanism of interferon action: in vivo activation of 91 kDa transcription factor.

Interferons are a family of secreted polypeptides with distinct biological effects. These effects include the regulation of expression of specific cellular genes, antiviral properties, and inhibition of cell growth and proliferation. We investigated the effect of sodium orthovanadate (vanadate), an inhibitor of protein-phosphotyrosine phosphatases, on early biochemical events associated with the stimulation of transcription factor p91 activation by interferon-alpha (IFN alpha) in live human cells. We report that the treatment of cells with vanadate selectively potentiated (2-3 fold) the levels of IFN-stimulated tyrosine phosphorylation of p91 (and not of p113) as compared to the levels of p91 activated by IFN alone and that this was associated with the increased accumulation of phosphorylated p91 in the nucleus, and the activation of protein tyrosine kinases that phosphorylate p91. These results suggest the possible involvement of a vanadate sensitive protein-tyrosine phosphatase(s) in the deactivation of phosphorylated p91 in live human cells.

Antineoplastic Agents↗

Awareness of AIDS among school children in Haryana.

The study is aimed to assess the existing level of knowledge of school children of 9th and 10th classes about Acquired Immune Deficiency Syndrome (AIDS). Three high schools in an urban area and three in the villages of a district of North India were included in the study. A pretested closed-ended questionnaire was administered to 336 students available. Overall level of knowledge about AIDS was found to be high. However, there were significant differences in knowledge among rural-urban and male-female students. There were some misconceptions in knowledge regarding transmission, prognosis and prevention. Books and media were the most common sources of information. Most of the students wanted to learn more about AIDS. Since overall knowledge levels were high we conclude that AIDS education should concentrate on clarifying areas of misconceptions.

Acquired Immunodeficiency Syndrome↗

Improvement in contractility of infarct zone after dobutamine infusion predicts good (TIMI II or III) flow in infarct related artery.

Eighteen patients of 'Q' wave acute myocardial infarction (AMI) (age 50 +/- 6.2 years), underwent dobutamine stress echocardiography (DSE) before hospital discharge (7.2 +/- 1.3 days after AMI) to find out the correlation between response of infarct zone to dobutamine infusion and TIMI grade flow in infarct related artery (IRA). The aim of study was to test the hypothesis that infarct zone which shows improvement in contractility after dobutamine infusion has viable myocardial tissue and would have good flow (TIMI II or III) in IRA. Echocardiographically, improvement in contractility in the centre of infarct zone by at least 1 grade (on a scale of 4) was termed as positive response on DSE. The mean dose of dobutamine was 19.4 micrograms/kg/min. Ten patients had positive response on DSE; 8 of them had good antegrade flow in IRA. Eight patients had no improvement in contractility of infarct zone on DSE; 6 of them had poor flow in IRA. Clinical markers of reperfusion (relief of chest pain, early ST settlement, peak CPK-MB levels), age of patient, site of AMI, time to thrombolysis, resting left ventricular ejection fraction, wall motion score of the infarct zone and presence of collaterals were not significantly different in patients with good or poor flow in IRA. Thus, improvement in contractility of infarct zone after dobutamine infusion can predict good flow (TIMI II or III) in IRA with 80 percent sensitivity, 75 percent specificity, 80 percent diagnostic accuracy, 80 percent positive predictive value and 75 percent negative predictive value.

Adult↗

Compliance of secondary prophylaxis for controlling rheumatic fever and rheumatic heart disease in a rural area of northern India.

This study was conducted in a community development block of a district in Haryana to evaluate the compliance of secondary prophylaxis for controlling rheumatic fever (RF) and rheumatic heart disease (RHD). The patients were interviewed using a semi-structured schedule at home. Currently 110 patients are registered in RF/RHD registry of which 53 (48.2%) are males. Mean age of patients was 18.4 +/- 8.6 years, ranging from 6 to 50 years with majority (48, 43.7%) of patients in the age groups of 6-15 and 16-25 years. Out of 110 patients, more than 90 percent had taken 11 out of the 12 due doses of secondary prophylaxis every year in the last eight years of the programme except in 1995 when 92 (83.6%) patients took the prophylactic doses. Only one patient reported recurrent attacks of rheumatic fever after irregular secondary prophylaxis. Eighteen (16.4%) patients were defaulters at the time of interview and were motivated to take secondary prophylaxis regularly. Ninety-seven (88.2%) patients were satisfied with the ongoing programme. In developing countries, it is possible to successfully apply a secondary prevention programme for control of RF/RHD by using existing health infrastructure.

Adolescent↗

Immunological studies in oral submucous fibrosis.

Oral submucous fibrosis (OSMF) is a high risk precancerous condition. The possible role of immunological factors in the pathogenesis of this condition was evaluated in 113 cases and 25 controls. The male/female ratio was 1.5/1. The mean age of males was significantly lower than that of females. The mean ESR levels were within normal limits, but for a higher than 20 mm fall per hr. in 40% of the cases. The serum IgA, IgG, and IgM levels were elevated significantly as compared to the controls. Circulating auto-antibodies and tissue-deposited antibodies were also found in 33% and 40% of the cases, respectively. From the analysis of the results, it is difficult to ascribe an auto-immune basis for the causation of OSMF. The female bias and elder age group, the factors generally considered in favour of an immune disorder, was not found in our study. However, raised ESR in 40% and serum globulin levels in 47% of the patients, distinctly higher levels of serum immunoglobulins, and positivity for circulating and tissue deposited antibodies in 33% and 34% of the cases respectively, do indicate an immunological basis. Therefore, further studies are required to ascertain the role of cellular immune mechanism and genetic parameters to explain the etiopathogenesis of this complex clinical entity.

Adolescent↗

Angiogenic molecules and cancer metastasis.

The progressive growth of primary neoplasms and metastases depends on the development of adequate vasculature, i.e., angiogenesis. The extent of vascularization in different malignancies correlates directly with their metastatic potential and, hence, inversely with the survival of the patient. The induction of neovascularization is mediated by both tumor cells and host cells and the interaction of the two. The balance of positive and negative regulatory molecules released by tumor cells and host cells determines the biological outcome which, in the case of tumor growth, favors angiogenesis.

Angiogenesis Inducing Agents↗

Effect of endothelial cells on the lymphoproliferative response in Takayasu's arteritis.

Takayasu's arteritis, also known as 'non-specific aortoarteritis' is an inflammatory disease of the aorta and its major branches. It also involves the pulmonary artery. The aetiology of the disease is not known so far. Abnormalities of the endothelial cells in terms of their structure and function are seen in the pathology of a number of diseases affecting the blood vessel wall. However, involvement of the endothelial cells in non-specific aortoarteritis is not known. In an effort to identify the role of endothelial cells in the pathogenesis of Takayasu's arteritis, peripheral blood lymphocytes isolated from the blood of patients suffering from Takayasu's arteritis were cultured in the presence of endothelial cells alone and in the presence of mitogens concanavalin-A and phytohaemagglutinin-P. The peripheral blood lymphocytes of patients with Takayasu's arteritis showed a significantly decreased blastogenic response to the mitogen concanavalin-A when cultured in the presence of endothelial cells. Our result thus suggests that endothelial cells may probably induce an inhibitory effect on the lymphocytes in patients with Takayasu's arteritis.

Adolescent↗

Scabies.

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Female↗

A pilot programme of MRSA surveillance in India. (MRSA Surveillance Study Group).

This surveillance study was conducted simultaneously at three centres across India. A total of 13,610 test samples from various sites were obtained. Microbiological methods employed were similar at the three centres. Identification of S aureus was based on the recognition of the production of coagulase with positive isolates being recorded as S aureus. Both tube coagulase tests and slide coagulase test were performed. Antimicrobial susceptibility testing of the isolated strains of staphylococcus aureus and staphylococcus epidermidis to various antimicrobial discs were carried out according to standardized disk diffusion method recommended by NCCLS. Of the total 739 cultures of S aureus, 235 (32%) were found to be multiply resistant with the individual figures for resistance being 27% (Bombay), 42.5% (Delhi) and 47% (Bangalore). MRSA is emerging to be a significant problem pathogen in the surgical setting with vancomycin probably the only reliable choice for these infections.

Cross Infection↗

Enzyme-linked immunosorbent assay and immunoblot study in Takayasu's arteritis patients.

Takayasu's arteritis or non-specific aortoarteritis is an inflammatory and stenotic disease of the aorta of questionable aetiology. Immunopathogenic mechanism, the precise nature of which is uncertain, is often suspected to be one of the basic causes of this disease. The present study was designed to estimate the antiaorta antibody titre in Takayasu's arteritis patients and to further locate the antigen in the vessel wall. Thirty clinically and angiographically proven cases of Takayasu's arteritis patients with appropriate controls were studied. Antiaorta antibody titres were estimated using Enzyme-Linked Immunosorbent Assay method. The controls included patients of vascular diseases other than Takayasu's arteritis, autoimmune diseases like rheumatoid arthritis and systemic lupus erythematosis and normal healthy individuals. Absorbance value at 492 nm at a dilution of 1:500 of the patients' sera was expressed as the antiaorta, antibody titre. There was significant difference (p < 0.005) between the mean value of the antibody titre in patients (0.471 +/- 0.073) and patients of other vascular diseases (0.209 +/- .056); autoimmune diseases (0.143 +/- .024); and, controls (0.108 +/- 0.012). Collagenase treatment of the aorta resulted in the fall of the antibody titre of aortitis patients (0.162 +/- 0.036) suggesting that the collagen might be one of the components responsible for autoantigenecity of aorta resulting in aortitis. The aortic extract was further subjected to 10 percent sodium dodecyle sulphate-polyacrylamide gel electrophoresis and immunoblot was done with Takayasu's arteritis patients' sera as well as controls' sera. The sera in 80 percent of Takayasu's arteritis patients immunoprecipitated a protein of molecular weight 45,000 (45 kilodalton) whereas only 15 percent patients of autoimmune disease group showed precipitation band though of lower molecular weight. Normal human sera gave no immunoprecipitation band. The precise nature of the antigen still needs to be identified.

Autoimmune Diseases↗