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Biomedical subjects

P R Rao

Publications and source records attributed to P R Rao.

At least 19 recordsLinked to original sources
PubMed1993

Role of calcium in biphasic immunomodulation by gamma-HCH (lindane) in mice.

gamma-HCH (Lindane) is reported to cause a biphasic immunomodulation-stimulation followed by suppression-after oral administration in mice. Role of calcium in this biphasic immunomodulation was assessed after 4, 12 and 24 wks of gamma-HCH administration. 45Ca-uptake was enhanced during the initial immunostimulation followed by decrease concomitant with immunosuppression. Lymphocyte proliferation was inhibited during both the phases of immune response by verapamil, a calcium channel blocker, and by trifluoperazine, a calmodulin inhibitor. These findings show an impairment of calcium homeostasis in lymphocytes culminating into the biphasic immunomodulatory effects of gamma-HCH.

Adjuvants, Immunologic↗
PubMed1992

Immunomodulatory effects of gamma-HCH (Lindane) in mice.

Mice were fed for 24 weeks with three different subtoxic dosages of gamma-HCH (0.012, 0.12 and 1.2 mg/kg) mixed in powdered feed. The immunological profile was assessed at an interval of one month during the entire exposure period. Both the cell mediated and humoral components of immunity showed a biphasic response characterized initially by stimulation followed by suppression in a dose dependent manner. However, gamma-HCH did not affect the functional properties of peritoneal macrophages. Histological changes in lymphoid organs were in accordance with the biphasic immunomodulatory effects of gamma-HCH.

Animals↗
PubMed1991

Erythrocyte glutathione metabolism in human chronic fluoride toxicity.

Chronic exposure of humans to toxic levels of fluoride in drinking water resulted in significant increase in blood GSH content with significant increase in the activities of erythrocyte glutathione metabolising enzymes viz., gamma-glutamylcysteine synthetase (E.C. 6.3.2.2), gamma-glutamyltranspeptidase (E.C. 2.3.2.2), GST (E.C. 2.5.1.18), GSH-Px (E.C. 1.11.1.9) and GR (E.C. 1.6.4.2). The data suggested a form of adaptation on the part of the erythrocytes to counteract the oxidative stress in red blood cells of fluorotic patients.

Adult↗
PubMed1991

Red cell membrane alterations in human chronic fluoride toxicity.

Red cells from humans exposed chronically to toxic levels of fluoride through drinking water showed significant increase in lipid peroxidation and membranous cholesterol and phospholipids. Additionally, electrophoretic patterns of ghost membrane proteins revealed the presence of a new band in the range of congruent to 66 Kd and increase in the high molecular weight protein and predominance of bands with a molecular weight of congruent to 93 Kd and congruent to 20 Kd. The activities of total, Na(+)-K(+)-, Mg(2+)- and Ca(2+)-ATPases were significantly decreased in the red cell ghosts of fluorotic patients.

Adenosine Triphosphatases↗
PubMed1991

Neurogenic stuttering as a manifestation of stroke and a mask of dysphonia.

R. L. was a 52-year-old man who was referred for an SLP consultation to determine the nature of his fluency disorder, whether or not treatment would be beneficial, and finally whether resumption of pre-trauma vocational status was feasible. The patient was involved in a motor vehicle accident with no resulting detectable trauma. However, shortly after the accident, R. L. developed a severe dysfluency that was later described as cortical stuttering. We reviewed the medical and rehabilitation work-up that attempted to determine whether the communication disorder was functional or organic in origin. Once the fluency disorder was determined to be caused by a suspected small, focal, hemispheric lesion, a five-month treatment program was undertaken that used a noval prosthetic approach to restore fluency. Once fluency was restored with the use of an artificial larynx, a residual anomia was detected and treated. The case of R. L. illustrates a stuttering that appeared to be caused by a combined neurogenic dyspraxic (vocal control), dysarthric (motor control), and dysnomic (word-finding) dysfluency. The literature on this issue was reviewed and the underlying mechanism of recovery was discussed.

Anomia↗
PubMed1991

Intraerythrocytic parasites and red cell deformability: Plasmodium berghei and Babesia microti.

In the studies reported here, we examined the effects of two intraerythrocytic parasites (Plasmodium berghei and Babesia microti) on the deformability of their host red cells. Red cell deformability was assessed by three criteria: 1) the prevalence of tank-treading (the tank-tread-like movement of the red cell membrane around its cytoplasmic contents), 2) elongation under fluid shear stress (the steady-state length: width ratio), and 3) the time required for the red cell to reduce its steady-state elongation by 63.2% after the abrupt release of the shear stress (the characteristic shape-recovery time). Trophozoite-stage parasites of both species reduced the prevalence of tank-treading. Ring- and trophozoite-stage parasites of both species reduced steady-state elongation, and ring-stage P. berghei prolonged the shape-recovery time. These results suggest that altered red cell deformability is a common feature of infection with intraerythrocytic parasites.

Animals↗
PubMed1990

Potential-dependent calcium channels in rabbit jejunum.

Potential-dependent calcium channels have been studied in the isolated rabbit jejunum. A biphasic response was observed, a transient and rapid contraction followed by partial relaxation and a sustained contraction attaining a plateau state. These are similar to the phasic and tonic responses observed in the isolated smooth muscles of other species. Both the responses are susceptible to blockade by the calcium antagonists bepridil, diltiazem, nifedipine, PN 200-110 (isradipine), and verapamil. Two calcium pools or the presence of two channels affecting the two responses are proposed.

Animals↗
PubMed1989

Genetic differentiation among some endogamous populations of Andhra Pradesh, India.

Endogamous populations belonging to Brahmin, Vysya, Mala, and Madiga castes of Andhra Pradesh, South India, were investigated for certain red cell enzyme and serum protein genetic markers. Frequency values were statistically analyzed to assess genetic variation among the populations. Average heterozygosity of ten loci and genetic diversity within and between the populations were calculated by using the methods of Nei. Nei's index was used to calculate genetic distances between the pairs of populations. A dendrogram was drawn adapting the modified unweighted pair group method suggested by Li, which agreed with the history of the populations.

Blood Group Antigens↗
PubMed1989

Humoral immune responses in dapsone treated M. leprae infected mice.

Humoral responses in M. leprae infected mice were studied through 52 weeks and were found to be directly related to the bacterial load. However, treatment with dapsone (DDS) in the last 12 weeks of infection resulted in an initial enhancement of the humoral responses followed by a gradual decrease, though they were still significantly high at the end of the study.

Animals↗
PubMed1988

Serum immune complexes in erythema nodosum leprosum reactions of leprosy.

Serum estimations of immunoglobulins, complement components and their presence in circulating immune complexes were carried out in 39 Lepromatous, 44 ENL and 22 Post ENL leprosy patients. Serum IgG, IgA, IgM, C3 and C4 levels were determined by single radial immunodiffusion. Serum immune complexes were precipitated with Polyethylene Glycol (PEG) and IgG, IgA, IgM, C3 and C4 were estimated by single radial immunodiffusion and expressed as % of precipitation of their serum level. Decreased IgG, IgM; increased IgA and C3; and no change in C4 levels are observed in ENL than Lepromatous and Post ENL patients. However, a gradual insignificant reduction of IgG, IgA, and IgM was found from Lepromatous to ENL and Post ENL patients in the PEG-precipitates. Similarly, C3 and C4 was found reduced insignificantly in ENL than Lepromatous and Post ENL patients. The significance of these estimations in relation to immune status of ENL reactions are discussed.

Adolescent↗
PubMed1987

Membrane stress and internal pressure in a red blood cell freely suspended in a shear flow.

Presented is an algorithm for the approximate calculation of the membrane stress distribution and the internal pressure of a steadily tank-treading red cell. The algorithm is based on an idealized ellipsoidal model of the tank-treading cell (Keller, S.R., and R. Skalak, 1982, J. Fluid Mech., 120:27-47) joined with experimental observations of projected length, width, and tank-treading frequency. The results are inexact because the membrane shape and velocity are assumed a priori, rather than being determined via appropriate material constitutive relations for the membrane; these results are, nevertheless, believed to be approximately correct, and show that internal pressure builds up slowly as cell elongation increases, rising more rapidly as the deformed cell approaches the limiting geometry of a prolate ellipsoid. The maximum shear stress resultant in the membrane was found to be below but approaching the yield point range at the highest shear rate applied.

Algorithms↗
PubMed1987

Prevalence of staphylococcal zoonosis in pyogenic skin infections.

S. aureus aetiology was found in 76.47% of the 102 pyoderma cases under study, with a high frequency of incidence in children below 5 years of age. The majority of the S. aureus isolates was nontypable (50.0%) and among the typable strains, phage group-III (31.0%), Group-I (20.7%) and a mixed phage group (34.5%) were predominant. 28.2% of the isolates were S. aureus var. bovis and 2.6% were S. aureus var. canis subgroups. Zoonoses in staphylococcal pyogenic skin infections were proved in 9 of the cases, which showed the history of direct animal contact supported by the isolation of S. aureus of animal host origin. Dogs, cattle and poultry were found to be the most important reservoirs transmitting S. aureus to humans, with folliculitis, furunculosis, impetigo as the frequent clinical manifestations.

Adolescent↗
PubMed1987

Enhanced cell-mediated immune responses in erythema nodosum leprosum reactions of leprosy.

Cell-mediated immune (CMI) responses were measured in 39 lepromatous, 44 erythema nodosum leprosum (ENL), and 22 post-ENL patients. The leukocyte migration inhibition test was used to measure CMI responses to mitogen phytohemagglutinin-P (PHA), crossreacting antigen purified protein derivative (PPD) of tuberculin, and armadillo-derived whole and sonicate Mycobacterium leprae. "Early T" lymphocytes of the peripheral blood were also enumerated using the rosetting technique. Significantly enhanced immune responses (lower migratory indices) were found to whole M. leprae during ENL. Although responses were high with PHA and PPD, they were identical in all of the groups, indicating that during ENL reaction M. leprae-specific responses are enhanced. "Early T" lymphocytes also showed a significant increase in ENL reactions compared to lepromatous patients. However, there was no response to the leprolin skin test in ENL patients in contrast to the enhanced in vitro CMI responses.

Adolescent↗