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Biomedical subjects

R Shankar

Publications and source records attributed to R Shankar.

At least 55 records · Page 3Linked to original sources
PubMed1996

Fetal iron status in maternal anemia.

Hemoglobin, serum iron, transferrin saturation and ferritin were measured on paired maternal and cord blood samples in 54 anemic (hemoglobin < 110 g/L) and 22 non-anemic (hemoglobin > or = 110 g/L) pregnant women at term gestation. The levels of hemoglobin, serum iron, transferrin saturation and ferritin were significantly low in the cord blood of anemic women, suggesting that iron supply to the fetus was reduced in maternal anemia. The linear relationships of these parameters with both maternal hemoglobin and maternal serum ferritin indicated that the fetus extracted iron in amounts proportional to the levels available in the mother. Infants of mothers with moderate and severe anemia had significantly lower cord serum ferritin levels and hence poor iron stores at birth. It is concluded that iron deficiency anemia during pregnancy adversely affects the iron endowment of the infant at birth.

Anemia, Iron-Deficiency↗
PubMed1996

Spermatotoxic effects of carbaryl in rats.

The spermatotoxic effect of carbaryl in adult and young male rats has been examined. Carbaryl 50 and 100 mg/kg b.wt. Male fed 5 d/week for 60 days, caused dose and age-dependent decline in epididymal sperm count and sperm motility, an increase in sperm with abnormal morphology. The dose of 25 mg/kg/d was a 'No observed effect level' for the indices studied. Young animals in comparison to adults exhibited pronounced spermatotoxic effects.

Administration, Oral↗
PubMed1996

Effect of haloperidol on phospholipid biosynthesis in rat brain.

Haloperidol, a butyrophenone used in the treatment of various psychoses has been clinically used and studied extensively. At the molecular level it is known to preferentially block D2 type of dopamine receptors but its other effects are unknown. We studied the effect of this drug on phospholipid biosynthesis in vitro by following incorporation of 32P into individual classes of phospholipids. It was observed that haloperidol inhibits the biosynthesis of almost all major phospholipids including phosphatidyl inositol at fairly low concentrations. It cannot be concluded from the present experiment which step the inhibition may be taking place but acyl transfer reaction is likely to be involved because the drug effects almost all the phospholipids. It is suggested that long-term use of the drug can effect the organization of synaptic membrane.

Animals↗
PubMed1995

Bi-directional stimulation of adherence to extracellular matrix components by human head and neck squamous carcinoma cells and endothelial cells.

Head and neck squamous cell carcinoma (HNSCC) cultures were established from two patients to determine if cancer and endothelial cells bi-directionally regulate their adherence to extracellular matrix components (ECM), an important process for tumor vascularization and metastasis. Soluble products from endothelial cells transiently enhanced adherence by HNSCC to ECM and increased surface levels of beta 1 and beta 4 integrins, although not beta 3. HNSCC products enhanced endothelial cell adherence to fibronectin and laminin, and beta 1 and beta 4 expression. These data show bi-directional enhancement of adherence to ECM and integrin expression among endothelial and tumor cells, which may facilitate metastasis and neovascularization.

Animals↗
PubMed1995

Gender differences in disability: a comparison of married patients with schizophrenia.

Gender differences in disability constitute a fertile area of research, as disabilities need to be measured and evaluated in the social context which defines role expectations and consequently the role performance. This paper reports on the differences in disability in married patients with schizophrenia, as marital status is an important determinant of role expectation. The study sample constituted 30 married patients, of both sexes, who satisfied DSM-III criteria for schizophrenia, and were living with their spouse at the time of assessment. Disability was evaluated using the DAS (modified version). The findings indicated that women were more disabled than men on many of the evaluation parameters (p < 0.05); there was also a strong correlation between negative symptoms and disability variables in both the sexes. While a correlation between PSE syndromes and disability variables was seen in the case of males, the relationship was not seen in females. Stepwise regression also revealed that negative symptoms predominated among the factors associated with global disability in both sexes. Most of the reports in the literature reveal that women are less disabled than men. The findings of this study, that women are more disabled than men, is discussed in the context of the social conditions prevailing in India.

Adult↗
PubMed1995

Diagnosis of uterine abnormalities with radionuclide imaging.

A pelvic hypervascular blush often creates a diagnostic dilemma during radionuclide abdominal imaging studies in females. This blush is shown to be due to uterine vascularity that is more prominent in the secretory and menstrual phases of the menstrual cycle. Significant uterine vascularity in the earlier phases is inappropriate and may be pathologic. Three such cases are presented in which increased uterine vascularity on radionuclide imaging during the proliferative phase either lead to a diagnosis or supported a clinical finding.

Adult↗
PubMed1995

TNF-alpha induces peroxynitrite-mediated depletion of lung endothelial glutathione via protein kinase C.

We tested the hypothesis that tumor necrosis factor-alpha (TNF) induces a peroxynitrite (ONOO-)-mediated depletion of glutathione via a protein kinase C (PKC)-dependent mechanism in pulmonary artery endothelial monolayers (PAEM). PAEM were incubated with TNF (1,000 U/ml) for 6 and 18 h. The PAEM were assayed for ONOO(-)-dependent changes in the concentration of luminol, free glutathione [Gfree; i.e., reduced glutathione and oxidized glutathione (GSSG)] and GSSG. TNF treatment decreased luminol and Gfree, and increased GSSG and GSSG/Gfree, compared with treatment with control media. The TNF-induced effects were prevented by co-incubation with the nitric oxide synthase inhibitors NG-monomethyl-L-arginine (1 mM), NG-nitro-L-arginine methyl ester (1 mM), or NG-nitro-L-arginine (1 mM). In addition, the TNF-induced effects were prevented by superoxide dismutase (10 U/ml), which removes O2-, and by urate (0.5 mM) and L-cysteine (3 mM), putative scavengers of ONOO-. The treatment of PAEM with the PKC activator phorbol 12-myristate 13-acetate (PMA, 1 microM) induced similar alterations in luminol and glutathione as TNF. TNF and PMA induced a protein of similar molecular weight (approximately 90 kDa) in the focal contact-rich fraction of PAEM lysate. TNF- and PMA-induced effects were prevented with the specific PKC inhibitor calphostin C (1 microM). The data indicate that TNF-induced PKC activation mediates ONOO- generation, which results in the oxidation and depletion of glutathione in PAEM.

Animals↗
PubMed1995

Multidisciplinary mental health teams.

This study surveyed current practice amongst 91 Indian and Australian staff working within multidisciplinary mental health teams, looking at leadership skills, conflict resolution and therapeutic abilities. Length of training was associated with management skills, though these skill were more developed by psychiatric nurses and occupational therapists working in community settings. Hospital settings involved less consensual decision-making than community teams. Psychiatric nurses spent most time in clinical work, and occupational therapists were rated as less skilled in the therapeutic activities assessed than any other profession. Psychiatrists and clinical psychologists undertook most research. The activities assessed in this study could be undertaken by a team comprising psychiatrists, psychiatric nurses and social workers, with clinical psychologists employed where possible, especially for research or service evaluation.

Australia↗
PubMed1995

Effect of oral administration of carbofuran on male reproductive system of rat.

1. Carbofuran was administered orally to adult male rats at dose levels of 0.1, 0.2, 0.4 or 0.8 mg kg-1 body weight, 5 d wk-1 for 60 days. A dose dependent decrease was observed in body weight of rats treated with 0.2-0.8 mg carbofuran kg-1 body weight. 2. A significant decrease in the weight of epididymides, seminal vesicles, ventral prostate and coagulating glands was observed at various test doses of carbofuran except at the lowest dose. 3. Decreased sperm motility, reduced epididymal sperm count along with increased morphological abnormalities in head, neck and tail regions of spermatozoa were observed in rats exposed to 0.2, 0.4, or 0.8 mg carbofuran kg-1 body weight. 4. In addition, significant alterations were observed in the activities of marker testicular enzymes viz. sorbitol dehydrogenase (SDH), glucose-6-P-dehydrogenase (G6PDH) (decreased), lactate dehydrogenase (LDH) and gamma-glutamyl transpeptidase (gamma-GT) (increased) depending on dose. 5. Histologically, the results indicated the toxicity of carbofuran on testes depending on dose. The changes predominantly consisted of moderate oedema, congestion, damage to Sertoli cells and germ cells, along with the accumulation of cellular debris and presence of giant cells in the lumen of a few seminiferous tubules which showed disturbed spermatogenesis with the higher doses of carbofuran. 6. These observations determined a no effect level dose of 0.1 mg kg-1 body weight of carbofuran on the biochemical and morphological indices studied for male reproductive toxicity assessment in the rat model. The results of the present study provide first hand information on the reproductive toxicity of carbofuran in male rats.

Administration, Oral↗
PubMed1995

Down regulation of CD11b and CD18 expression in atherosclerotic lesion-derived macrophages.

Monocyte/macrophages play an important role in the development of atherosclerosis. Electron microscopic evidence suggests that in the early stages, lipid laden monocytes leave the lesion to reenter the circulation. This reverse monocyte traffic ceases as the lesion develops. We hypothesize that monocyte/macrophages may not be able to exit the lesion and reenter the circulation because of the reduced expression of CD11/CD18 integrins. We have compared CD11b and CD18 expression of peripheral blood monocytes from normal rabbits (NMø) to atherosclerotic lesion-derived macrophages (AthMø) by anti-CD11b and anti-CD 18 antibody staining, followed by flow cytometry and immunohistochemical staining. AthMø were isolated from aortic lesions of rabbits fed 2 per cent cholesterol diet following balloon angioplasty. AthMø were separated into two regions based on their size and granularity by flow cytometry. All macrophages stained positively with RAM 11. Our results indicated that NMø showed a strong cell surface expression of CD11b and CD18. The less granular and smaller AthMø showed little anti-CD11b or anti-CD18 antibody staining, indicating very little CD11b or CD18 antibody staining, indicating very little CD11b or CD18 expression. The more granular and larger cells showed surface expression of both CD11b and CD18. With respect to CD18, over 90 per cent of NMø expressed CD18, only 37 per cent of the large granular AthMø and less than 1 per cent of the smaller, less granular AthMø stained positive for CD18. Immunohistochemical studies revealed strong surface expression of CD11b and CD18 on normal monocytes.(ABSTRACT TRUNCATED AT 250 WORDS)

Angioplasty, Balloon↗
PubMed1995

Effects of carbaryl on the rat's male reproductive system.

Carbaryl was orally administered to male albino rats at 50 mg or 100 mg carbaryl/kg body weight 5 d/w for 90 d. A significant decrease in weight gain was observed at the high dosage after 60 d. Although no significant changes in the weight of testes, epididymides and accessory sex organs occurred, moderate to marked histopathological changes in the testes were seen at both dosage levels. Testicular enzymes associated with post-meiotic spermatogenic cells (sorbitol dehydrogenase) decreased, while lactate dehydrogenase increased concomitant with the observed degeneration of spermatogenic cells. Enzymes associated with pre-meiotic spermatogenic cells or Sertoli cells (gamma-glutamyl transpeptidase) increased, while glucose-6-phosphate dehydrogenase decreased. These effects were dose related and associated with declines in epididymal sperm count and percent sperm motility and increased abnormal sperm morphology.

Administration, Oral↗
PubMed1994

Thrombin receptor-activating peptides differentially stimulate platelet-derived growth factor production, monocytic cell adhesion, and E-selectin expression in human umbilical vein endothelial cells.

Recent studies have shown that the synthetic peptides SFL LRN and SFL LRN PND KYEPF (thrombin receptor-activating peptides (TRAP)) derived from the deduced sequence of the new amino terminus of the cleaved thrombin receptor can mimic thrombin receptor activation, act as full agonists for platelet activation, and induce prostaglandin I2 production as well as cytosolic Ca2+ increase in human umbilical vein endothelial cells (HUVEC). Here, we have compared the ability of these synthetic peptide ligands and thrombin to stimulate platelet-derived growth factor (PDGF) production by, and monocyte adhesion to, HUVEC. Thrombin (50 units/ml) and TRAP (25 microM) maximally stimulated monocyte adhesion. Furthermore, the stimulation of E-selectin cell surface expression and the steady-state E-selectin mRNA levels by thrombin and TRAP were comparable. Thrombin (50 units/ml) stimulated PDGF production 400% above the basal level in 24 h, whereas the 6-mer and 14-mer TRAP, even at 200 microM, did not significantly stimulate PDGF production. Northern analysis, however, revealed that TRAP at 100 microM stimulated PDGF-A and -B chain mRNA expression to a level similar to that induced by thrombin. These results suggest that activation of cell signaling by TRAP can mimic thrombin and is sufficient for the stimulation of monocyte adhesion to HUVEC; however, thrombin-stimulated PDGF production by HUVEC may require mechanisms in addition to the signaling events initiated by TRAP or may require the participation of a novel thrombin receptor.

Amino Acid Sequence↗