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Biomedical subjects

S Kumar

Publications and source records attributed to S Kumar.

At least 1,279 records · Page 71Linked to original sources
PubMed1995

Effect of treatment with a hydroxymethylglutaryl coenzyme A reductase inhibitor on fasting and postprandial plasma lipoproteins and cholesteryl ester transfer activity in patients with NIDDM.

Patients with non-insulin-dependent diabetes mellitus (NIDDM) have a greater risk of developing coronary heart disease than would be expected from a similar degree of hyperlipidemia in nondiabetic populations. Accelerated transfer of cholesteryl esters (CET) from high-density lipoprotein (HDL) to low-density lipoprotein (LDL) and very-low-density lipoprotein (VLDL), a process that is associated with atherosclerosis, may be a possible explanation for this. CET, plasma lipoprotein concentration, and mass in the fasting and postprandial state have been examined in 31 hyperlipidemic patients with NIDDM before and after 8 weeks of treatment with the hydroxymethylglutaryl (HMG)-coenzyme A (CoA) reductase inhibitor pravastatin in a double-blind, placebo-controlled, parallel group study. Body mass index, glycemic control, and blood pressure remained unaltered during the study period. Compared with placebo, pravastatin decreased fasting serum cholesterol (P < 0.001) and LDL cholesterol (P < 0.002) levels. The high basal CET (34.4 +/- 13.1 nmol.ml-1.h-1) was decreased significantly by pravastatin treatment (27.5 +/- 13.7 nmol.ml-1.h-1, P = 0.013). There was a fall in the total cholesterol, free cholesterol, and phospholipid content of the Sf 0-12, 20-60, and 60-400 lipoproteins (all P = 0.001). Lecithin: cholesterol acyl transferase activity was not altered. The postprandial increase in VLDL cholesterol 5 h after a standardized mixed meal was attenuated after pravastatin treatment (P = 0.011). Inhibition of hepatic cholesterol synthesis with an HMG-CoA reductase inhibitor in hyperlipidemic patients with NIDDM decreased serum cholesterol content of triglyceride-rich lipoprotein, thereby decreasing the transfer of cholesteryl ester from HDL to LDL and VLDL.

Adult↗
PubMed1995

Isolation and characterisation of a hyaluronan binding protein, hyaluronectin, from human placenta and its colocalisation with hyaluronan.

Hyaluronan (HA) is a major component of the extracellular matrix and is known to influence cell behaviour and to play a role in angiogenesis, morphogenesis and tissue remodelling, although little is known concerning the regulation of these effects. Until now its detection in the placenta has been by indirect methods, which has led to conflicting conclusions as to its distribution and hence its role. Hyaluronectin (HN) is one of a group of proteins with HA binding ability which may regulate the effects of HA. Although nervous tissue HN has been partly characterised with regard to its distribution, structure and biochemistry, little is known about the mesenchymal isoform and its distribution in placenta has not previously been reported. Using specific probes we have characterised the distribution of HA and HN in human placental tissue. At all stages of development studied (8, 10, 12, 30 and 38 wk gestation) HA and HN were unequivocally colocalised, being distributed in the extracellular matrix of stromal tissue of placental villi, chorioallantoic membranes and umbilical cord. Particularly strong immunoreactivity was observed in the villous stroma immediately adjacent to fibrinoid depositions at sites of denudation of the trophoblast layer. Extraction and characterisation of the HN from placental villi have revealed 4 major glycoproteins of 47, 52, 57 and 67 kDa, this being a different pattern and smaller molecular range than observed for the nervous tissue form. This is the first direct demonstration of the presence of HA and HN in the placenta and identifies an abundant new source of mesenchymal HN. The functions of mesenchymal HN are unknown but may include ion exchange, immunosuppression and regulation of the effects of HA in such roles as maintenance of tissue architecture, cell migration and angiogenesis.

Blotting, Western↗
PubMed1995

Comparative activity of three repellents against bedbugs Cimex hemipterus (Fabr.).

Comparative activity of three repellents viz., diethyl-m-toluamide (DEET), diethyl phenyl-acetamide (DEPA) and dimethylphthalate (DMP) against bedbugs Cimex hemipterus (Fabr) was studied by applying repellent solution on the shaven skin of rabbits. DEET (Tech. grade) 20mgai/cm2 exhibited 93 and 83 per cent repellency after 2 and 8 h respectively, while DEPA (Tech. grade) at this concentration exhibited 90 and 71 per cent repellency. DEET and DEPA at 75 per cent concentration (15mgai/cm2) showed 85 and 78 per cent repellency up to 2 h and 52 and 42 per cent repellency 6 h after treatment respectively. The repellent activity was also found to be concentration and time of treatment dependent in respect of DEET and DEPA. DMP (Tech. grade) did not show any appreciable repellent activity at any concentration tested. Further, the blood intake by C. hemipterus following treatment with various concentrations of repellents was found to decrease with increase in the concentration of repellents.

Animals↗
PubMed1995

Rat mitochondrial mtDNA-binding proteins to inter-specifically conserved sequences in the displacement loop region of vertebrate mtDNAs.

We describe two new inter-specifically conserved sequences named Mt5 and Mt6 elements which are around the termination associated sequence (TAS) at the 3' end of the displacement loop (D-loop) region of vertebrate mtDNAs. We employed gel mobility shift assay to search for D-loop-binding proteins using partially purified rat mitochondrial mtDNA-binding proteins and 10 human DNA fragments covering the entire D-loop region as probe DNAs. Competition binding assays indicated the presence of four different rat mitochondrial D-loop-binding proteins. Each of the rat proteins bound, in a sequence-specific manner, to a probe DNA containing an inter-specifically conserved sequence; TAS, Mt5, B block, and a A+T-rich sequence overlapping the conserved sequence block I.

Animals↗
PubMed1995

Multiple dust allergy in a semiurban environs.

Multiple dust allergy in a study of 100 patients of nasobronchial hypersensitivity has been demonstrated by skin testing in Chandigarh and successfully desensitised over a 3-year period. The results are discussed and the multiple factors involved postulated.

Adolescent↗
PubMed1995

Localisation and cellular origin of hyaluronectin.

Hyaluronectin is an extracellular matrix glycoprotein which specifically binds to hyaluronan. Isoforms of hyaluronectin are present in nervous and mesenchymal tissues but, while the nervous tissue isoform has been characterised in some detail, less is known about the mesenchymal isoform. Although its tissue localisation suggests a role in tumour development, neither its cellular origin nor its exact function are known. In this study we demonstrate hyaluronectin synthesis in fibroblasts and smooth muscle cells in vitro. The pattern of immunolocalisation of hyaluronectin in fibroblasts depended on the cell type, length of time spent by the cells in culture and cell density. Immunoreactivity in sparsely plated migratory cells was seen mainly in a patchy distribution at the attached cell surface and in the migration tracks left by the cells on the subtratum. In stationary cells a more uniform distribution associated with the attached cell surface was observed, while in confluent cultures hyaluronectin immunoreactivity was mainly seen as a network of fibrillar material above the cell. The pattern of staining was distinct from that of other hyaluronan-binding proteins. Immunoprecipitation, using antihyaluronectin antibodies, of the substratum-attached material deposited by human fetal fibroblasts revealed a family of proteins ranging from 22 to 90 kDa, the major protein being of approximately 60 kDa. These results lead us to propose that hyaluronectin plays an important role in cell migration, probably by regulation of hyaluronan distribution and binding.

Adult↗
PubMed1995

Antioxidative enzyme in the liver of rats after exposure to xylene, toluene and methyl alcohol separately and in combination.

Antioxidative enzymes viz: glutathione peroxidase, glutathione reductase, catalase and aldehyde dehydrogenase were determined in the liver of rats treated with three industrial solvents viz: xylene, toluene and methyl alcohol both separately and in combination. Inhibited activity of glutathione peroxidase suggests reduction of hydroperoxides to corresponding alcohols. However, activity of glutathione reductase increased so as to maintain the glutathione (GSH) reserves. Catalase protected the rats by counteracting the superoxide radicals. However, inhibition of aldehyde dehydrogenase is attributed to the decreased availability of sulfahydryl groups. A trend to optimization of enzyme activities in the liver of co-treated rats suggests enhanced metabolism and excretion of xylene and toluene in the presence of methyl alcohol.

Aldehyde Dehydrogenase↗
PubMed1995

Variation in the modulation of superoxide-induced single-strand breaks in plasmid pBR322 DNA by biological antioxidants.

Superoxide radical (O2-.), generated by the xanthine-xanthine oxidase system, induces significant amount (20%) of single-strand breaks in plasmid pBR322 DNA. This is almost completely inhibited by its specific scavenger, superoxide dismutase. The biological antioxidants, at near physiological concentrations show great variation in their modulation of DNA damage induced by O2-.. The thiols glutathione, cysteine and dithiothreitol do not protect DNA, instead they greatly enhance the strand-breaking activity of this free radical. However, the lipid soluble antioxidants tannic acid, butein, canthaxanthin, beta-carotene and lipoate offered significant protection to plasmid DNA against O2-.. Since O2-. is the most abundant reactive oxygen species generated, the above mentioned modulating abilities of biological antioxidants may have significant biological implications.

Antioxidants↗
PubMed1995

Depression in general clinical practice--a diagnostic problem.

The study was conducted on 100 patients suffering from depression with the aim to highlight the common manifestations of depression in people belonging to a developing country like India, and to apprise the general practitioners and medical specialists of various disciplines, of various manifestations of depression to help early detection and timely treatment of the problem. It was observed that depression had varied manifestations like depressed mood, anxiety, somatic features, insomnia, lack of interest, paranoid ideas, obsessions, etc. Although 100% of patients had depressed mood but only 22% actually complained of it. Most patients often selectively highlighted somatic manifestations and overtly suppressed the mood component, thereby posing a diagnostic problem to the physician.

Adult↗
PubMed1995

Post-mastectomy seroma: a new look into the aetiology of an old problem.

Postmastectomy seroma (PMS) remains an unresolved quandary as the risk factors for its formation have still not been identified. Sixty-four consecutive female patients undergoing Halsted mastectomy were prospectively studied for this purpose. The risk factors that were studied included age and weight, diabetes, hypertension, tumour (size and location) and nodal (positive or negative) status and the use of perioperative blood transfusion. Additionally, the effect of PMS on total hospital drainage (THD), post-operative hospital stay and other wound-related complications were assessed. The incidence of PMS in this study was 28%, and those patients with PMS were designated as group A while the remaining patients were designated as group B. Group A patients were significantly older (P < 0.02) and heavier (P < 0.05) than group B patients; also, there were significantly (P < 0.0001) greater number of hypertensive patients in group A than in group B. In terms of other risk factors the two groups were statistically similar. Group A patients had significantly greater (P < 0.01) amount of THD than group B patients. Although no septic complications were observed as a result of seroma, its presence significantly (P < 0.0001) lengthened the post-operative hospital stay in group A patients. It is concluded that (1) PMS is a common problem, (2) its occurrence significantly increases the post-operative hospital stay, and (3) hypertension is perhaps the most important risk factor for its causation. Hypertension contributes to seroma formation, probably by way of prolonged oozing from the large mastectomy wound.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1995

Immunogenicity and in vivo efficacy of recombinant Plasmodium falciparum merozoite surface protein-1 in Aotus monkeys.

BACKGROUND: The carboxy-terminus of the merozoite surface protein-1 (MSP1) of Plasmodium falciparum has been implicated as a target of protective immunity. MATERIALS AND METHODS: Two recombinant proteins from the carboxy-terminus of MSP1, the 42 kD fused to GST (bMSP1(42)) and the 19 kD (yMSP1(19)), were expressed in Escherichia coli and secreted from Saccharomyces cerevisiae, respectively. To determine if vaccination with these recombinant proteins induces protective immunity, we conducted a randomized, blinded vaccine trial in two species of Aotus monkeys, A. nancymai and A. vociferans. After three injections using Freund's adjuvant, the monkeys were challenged with the virulent Vietnam Oak Knoll (FVO) strain of P. falciparum. RESULTS: All three control monkeys required treatment by Day 19. Two of three monkeys vaccinated with bMSP1(42) required treatment by Day 17, whereas the third monkey controlled parasitemia for 28 days before requiring treatment. In contrast, both of the A. nancymai vaccinated with yMSP1(19) self-resolved an otherwise lethal infection. One of the two yMSP1(19)-vaccinated A. vociferans had a prolonged prepatent period of > 28 days before requiring treatment. No evidence of mutations were evident in the parasites recovered after the prolonged prepatent period. Sera from the two A. nancymai that self-cured had no detectable effect on in vitro invasion. CONCLUSIONS: Vaccination of A. nancymai with yMSP1(19) induced protective immune responses. The course of recrudescing parasitemias in protected monkeys suggested that immunity is not mediated by antibodies that block invasion. Our data indicate that vaccine trials with the highly adapted FVO strain of P. falciparum can be tested in A. nancymai and that MSP1(19) is a promising anti-blood-stage vaccine for human trials.

Amino Acid Sequence↗
PubMed1995

Aneurysmal form of aortoarteritis with aberrant right subclavian artery: diagnosis by Magnetic Resonance Angiography.

Magnetic Resonance Angiography is rapidly advancing as an important imaging modality for vascular disorders. With increasing experience, it bids fair to replace catheter angiography as the diagnostic procedure of choice in select clinical conditions. We report a case of aneurysmal aortoarteritis with renal failure, in which magnetic resonance angiography proved to be a valuable substitute for conventional studies. In addition, the right subclavian artery had an aberrant origin, an unusual association.

Adult↗
PubMed1995

DNA profiling of the VNTR locus D2S44 in the population of Madras City and in the tribal Kotas of the Nilgiri Hills, south India.

Allele frequency distribution of the VNTR locus D2S44 was studied in Tamil Nadu (South India) population. Randomly chosen individuals (Tamils of the plains, Madras City; N = 142) were tested for HaeIII-generated polymorphism detectable by probe YNH24, and the allele sizes and frequencies were determined. Heterozygosity (93.6%) observed in the Tamils is comparable to that of other populations; the size and frequency distribution of alleles, however, vary significantly. The most prevalent allele, which ranges from 1.2 to 1.9 kb, appears to be unique to the Tamil Nadu population. No mutation was observed for the D2S44 locus in family material made up by 54 subjects (N = 54) including 37 offspring. DNA polymorphism at D2S44 locus was also studied in the endogamous Kota tribe of the Nilgiri Hills, South India, using enzyme HaeIII and probe YNH24. The Kota group (N = 48) is characterized by a very high frequency (32.3%) of the bin 1197-1352 bp. The DNA profile of the Kotas shows distinct differences from that of the urban population in the plains of Tamil Nadu, South India (Tamils of Madras City). The results have also been compared with the literature available on other world populations. The outcome indicates the uniqueness of the tribal Kotas and warrants the importance of DNA profiling in other tribal, caste/endogamous groups of India. This report incidentally represents the first comprehensive DNA profiling data for the locus D2S44 from India fulfilling the requirement for forensic and other applications.

Alleles↗
PubMed1995

Significance of exercise induced increase in diastolic pressure as an indicator of severe coronary artery disease.

A total of 100 patients were studied for the diastolic blood pressure response to treadmill exercise testing. No change in the diastolic pressure or lowering of the pressure was considered normal response. Seventy four patients had normal and 26 patients had abnormal diastolic blood pressure response. Out of these, 40 patients underwent coronary angiography. Fifty five percent of the patients with normal diastolic pressure response had normal coronaries compared to 20% with abnormal response (p < 0.03). Fifteen percent with normal response had triple vessel disease or left main coronary artery disease whereas forty percent with an abnormal response had significant disease (p < 0.03). Exercise induced ST segment depression was almost equal in both groups. Hence we can conclude that abnormal diastolic pressure response to treadmill exercise testing is a fairly good indicator of coronary artery disease irrespective of ST segment changes.

Blood Pressure↗
PubMed1995

Bone marrow involvement in Hodgkin's disease -- clinicopathological study of seven cases.

Bone marrow involvement was observed in 7 cases amongst a total of 75 cases of Hodgkin's disease encountered between January 1981 and June 1990; thus representing an incidence of 9.3 percent. Analysis of these 7 cases showed male preponderance. The age ranged from 26 to 74 years. All patients presented within seven months of onset of symptoms; and all had symptoms at presentation. Lymphadenopathy was found in all the cases, splenomegaly was present in six; and hepatomegaly in 4 cases. Mixed cellularity and lymphocytic depletion subtypes showed the highest frequency of marrow involvement (6 cases; 85.7 percent). Alkaline phosphatase was raised in 6 cases (85.7%). All cases received standard combination chemotherapy with or without local radiation therapy. Two years follow-up revealed an overall survival of 42.9%. Replace free survival at the end of two years was zero, as all the cases relapsed within seven months of initiation of treatment.

Adult↗