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Biomedical subjects

O M Prakash

Publications and source records attributed to O M Prakash.

10 recordsLinked to original sources
PubMed1995

Chronic & infrequent opioid exposure suppresses IL-2R expression on rhesus monkey peripheral blood mononuclear cells following stimulation with pokeweed mitogen.

In the present investigation, infrequent and chronic (daily) exposure of rhesus monkeys to morphine was investigated for their effect on cytokine receptor expression, interleukin (IL)-2-production, and the nuclear factor kappa B (NF kappa B) levels following stimulation with PWM. In a time-dependent manner, peripheral blood mononuclear cells (PBMCs) from both infrequent- and daily-morphine treated monkeys displayed significantly less (40 +/- 7%) IL-2 receptor compared to PBMCs from saline-treated controls. However, PBMCs from chronic opioid- and infrequent opioid-treated monkeys displayed similar levels of IL-4 and IL-7 receptors compared to saline-treated animals. Following stimulation with PWM, PBMCs from chronic opioid-treated monkeys produced elevated levels of IL-2 (870 +/- 94 pg/ml) compared to IL-2 levels (463 +/- 88 pg/ml) of PBMCs from saline-treated monkey. Likewise, PBMCs from chronic-morphine exposed monkeys had elevated levels (43%) of NF kappa B compared to PBMCs from saline-treated (control) monkeys following 72 hours in culture with PWM. Collectively, these observations suggest morphine regulates selective molecular events that manifest in biologically altered immune function including T cell activation and IL-2 production.

Animals↗
PubMed1993

Solution conformations of the peptide backbone for DPDPE and its beta-MePhe4-substituted analogs.

The solution structures of DPDPE, a conformationally restricted pentapeptide with the sequence H-Tyr1-D-Pen2-Gly3-Phe4-D-Pen5-OH, and its four beta-MePhe4-substituted analogs were examined by a combined approach including the NMR measurements in DMSO and water as well as independent energy calculations. It was concluded that several low energy conformers of DPDPE backbone satisfy the NMR data obtained in this study as well as in previous studies by other authors. These possible solution conformers of DPDPE in both DMSO and water share virtually the same type of cyclic backbone structure, with the Gly3 residue in a conformation close to a gamma-turn, and the Phe4 residue in a conformation close to alpha-helical torsion angles. They differ in the space arrangements of the flexible Tyr1 moiety. The solution structures of the beta-MePhe4-substituted analogs of DPDPE are interesting. For analogs with an S-configuration at the C alpha atom in the Phe4 residue, the cyclic backbone conformations resemble those of DPDPE itself, whereas for analogs with an R-configuration at the C alpha atom, the backbone conformation is somewhat different. This observation is in line with the high biological potencies and selectivities displayed by the former compounds but not by the latter ones. It was noted also that as far as the peptide backbone conformers are concerned, some of the possible DPDPE conformers in water are similar to the previously suggested model for the delta-receptor-bound conformation of DPDPE, becoming virtually identical to this conformation by rotating the side chains of the Tyr1 and the Phe4 residues.

Amino Acid Sequence↗
PubMed1986

Psychiatric morbidity in a general practice in an Indian city.

Psychiatric morbidity in an Indian general practice was studied using the 12 item version of the General Health Questionnaire to screen 882 patients who represented 9000 consecutive adult patients attending the practice. The questionnaire was valid with a cutting score of 1/2 when compared with section 1 of the standardised Indian Psychiatric Survey Schedule. The probable prevalence of psychiatric morbidity was 35.9%. The general practitioner identified only about 25% of patients. Five of the 12 questions on the General Health Questionnaire had a higher discriminatory capacity, and the performance of the patients on these five questions was valid when compared to section 1 of the Indian Psychiatric Survey Schedule.

Adult↗
PubMedDate not supplied

The interaction of insulin and angiotensin II on the regulation of human neuroblastoma cell growth.

This laboratory has previously reported that angiotensin II is a growth factor for human SH-SY5Y neuroblastoma cells, and that a variety of converting enzyme inhibitors and angiotensin II antagonists reduce thymidine incorporation into the DNA of these cells. In the present study, insulin, at 5 micrograms/mL, was found to stimulate thymidine incorporation in SH-SY5Y cells. The insulin effect was only partially inhibited by the converting enzyme inhibitors enalapril, quinapril, and quinaprilat, whereas it was markedly or totally blunted by the angiotensin II antagonists DuP753 and PD123177. In additional studies, IGF-1 (50 ng/mL) significantly stimulated thymidine incorporation into these cells in a fashion indistinguishable from that of insulin. Taken together, these studies are consistent with the suggestion that insulin at high concentrations and IGF at low concentrations enhance the proliferative response of these cells to angiotensin II. The differential effects of converting enzyme inhibition and angiotensin II antagonism on cell proliferation could be explained if converting enzyme inhibition results in low, but effective, levels of angiotensin II in the culture medium, whereas the angiotensin II antagonists effectively block angiotensin II at its receptor. Finally, in this system, both the AT1 receptor blocking agent DuP 753 and the AT2 receptor blocking agent PD123177 appear to be effective.

Angiotensin II↗
PubMedDate not supplied

Immunotherapy in allergic conjunctivitis.

Eighty patients with allergic conjunctivitis were treated with immunotherapy employing specific allergens. Sixty-two percent of these showed beneficial response. In cases of vernal conjunctivitis needing topical steroid preparations frequently for control of symptoms, immunotherapy is worth attempting to cause remission of symptoms.

Adolescent↗