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Biomedical subjects

R Singh

Publications and source records attributed to R Singh.

At least 667 records · Page 37Linked to original sources
PubMed1983

Tryptophan hydroxylase and 5-HTP-decarboxylase activity in cockroach brain and the effects of p-chlorophenylalanine and 3-hydroxybenzylhydrazine (NSD-1015).

The activities of two enzymes of the serotonin biosynthetic pathway, namely tryptophan hydroxylase (TPH) and 5-hydroxytryptophan-decarboxylase (5-HTP-D), were determined in the cockroach, Periplaneta americana, brain using radiometric techniques, significant levels of both enzymes were found. p-Chlorophenylalanine (PCPA) inhibited brain TPH activity strongly both in vitro and in vivo. In vitro, 10 mM PCPA reduced the TPH activity by 76% and in vivo either 15 micrograms/g or 30 micrograms/g of PCPA inhibited brain TPH activity by 80-85%. The activity of 5-HTP-D enzyme was inhibited significantly in vivo by 3-hydroxybenzylhydrazine, commonly known as NSD-1015. A recovery in the activity of 5-HTP-D enzyme was observed 12 h after 50 micrograms/g of NSD-1015 but 100 micrograms/g caused an inhibition lasting for the 24 h period studied.

Animals↗
PubMed1983

Dermatomic distributions of hypopigmented macular lesions of leprosy: neural dependence of melanocytic functions.

Dermatomic analysis of the distribution of the hypopigmented patches of leprosy has revealed a pattern wherein patches are most frequent in dermatomes of the brachial plexus, decrease gradually in frequency in succeeding spinal segments and increase again in dermatomes of the lumbar plexus. The predilection of hypopigmented patches for certain dermatomes may be a reflection of easy vulnerability of the neural pigmentary mechanism and/or a reflection of selective multiplication of M. leprae in nerves of certain dermatomes, even though the organisms might have been seeded all over the body by hematogenous spread. These preliminary observations are discussed.

Afferent Pathways↗
PubMed1983

Cell mediated inhibition of erythropoiesis and megaloblastic anemia in T-cell chronic lymphocytic leukemia.

A patient with T-cell chronic lymphocytic leukemia presented with severe megaloblastic anemia with normal serum folic acid and cobalamin concentrations. BFU-E could not be cultured from the patient's peripheral blood unless T-lymphocytes were removed by E-rosette formation. Inhibitory activity by the patient's T-cells was restricted to autologous BFU-E. After cyclic chemotherapy the anemia and megaloblastic changes resolved, peripheral blood BFU-E could be cultured from unfractionated peripheral blood and the T-cell inhibitory activity could no longer be demonstrated. The anemia in this patient is probably due to the neoplastic expansion of a suppressor T-lymphocyte population.

Adult↗
PubMed1983

Noninvasive evaluation of a left ventricular pseudoaneurysm: complementary role of echocardiographic and nuclear techniques.

This 45-year-old white male was evaluated for congestive heart failure initially ascribed to a rapidly progressive cardiomyopathy. Both radionuclide ventriculography and echocardiography correctly identified a left ventricular pseudoaneurysm as the cause for heart failure. Thallium-201 scintigraphy, by demonstrating a large perfusion defect, suggested a large ostium of the pseudoaneurysm. Following resection of the false aneurysm, a Dacron prosthesis was required to close a large posterior wall defect. We conclude that both radionuclide ventriculography and echocardiography can independently demonstrate a left ventricular pseudoaneurysm. The combined noninvasive approach is able to delineate various anatomical aspects of the pseudoaneurysm and help in planning adequate surgical intervention.

Cardiac Catheterization↗
PubMed1983

Parathyroid and ultimobranchial glands of the sand boa, eryx johnii Daudin.

Eryx johnii and E. conicus possess two pairs of parathyroid glands (PTG) and one pair of ultimobranchial glands (UBG). The PTG is composed of cell cords and follicles, and is well vascularized. The presence of large vesicles with ciliated and glandular epithelium is the most striking feature of the PTG in E. johnii. Accessory PTG tissues are present. The unique feature of equal sized UBGs in Eryx is their location, i.e., bilaterally parallel and rostrally away from the thyrothymic region. The UBG is composed of follicles and cell aggregates, which are interspersed in a vascularized connective tissue stroma; ciliated and goblet cells are frequently present. The UBG of Eryx shows aging variation, but not seasonal changes; seasonal histological variations are observed in the PTG.

Animals↗
PubMed1983

Parathyroid gland of the freshwater snake Natrix piscator Schneider.

The structure and function of the parathyroid glands of freshwater snake, Natrix piscator, were studied. N. piscator has two pairs of parathyroid glands which are composed of cell cords of typical endocrine appearance, and follicles are absent. Parathyroidectomy was followed by significant (P less than 0.001) hypocalcemia and hyperphosphatemia throughout the 5th week of experimental period. Following parathyroidectomy, calcium and phosphate concentrations in bone were significantly (P less than 0.05) increased after 5 weeks; however, these values in muscle were not significantly changed. Tetany was also observed in parathyroidectomized snakes. Histological structure and function of the glands do not appear to vary seasonally. Administration of parathyroid gland extract of this ophidian reptile into rats caused significant (P less than 0.05) elevation of serum calcium.

Animals↗
PubMed1983

Effect of centrophenoxine on the antioxidative enzymes in various regions of the aging rat brain.

This study investigated the effect (in vivo) of centrophenoxine (Helfergin) on the activity of antioxidant enzymes (glutathione peroxidase GSH-PER, glutathione reductase GSSG-RED, superoxide dismutase SOD and catalase) in subcellular fractions from the regions of the brain (cerebrum, cerebellum and brain stem) of rats aged 6, 9 and 12 months. In all age groups, normal (control) activity of GSH-PER, GSSG-RED and SOD in the three brain regions was higher in the soluble fractions than in the particulate fractions. The three regions of the brain showed different levels of the enzyme activities. Enzymes in soluble fractions (except GSSG-RED in cerebrum of rats aged 12 months) did not change with age. In particulate fractions, however, the enzymes showed age-related changes: GSH-PER decreased with age in cerebellum and brain stem, but showed an age-related increase in cerebrum, GSSG-RED and SOD increased with age in all the three brain regions. Catalase activity in all the three brain regions remained unchanged in all age groups. Six week administration of centrophenoxine (once a day in doses of 80 mg/Kg and 120 mg/Kg) to the experimental animals produced increases in the activity of SOD, GSH-PER and GSSG-RED in particulate fractions from all the three brain regions. In the soluble fractions, however, only SOD and GSH-PER activity was increased. In vitro also centrophenoxine stimulated the activity of GSH-PER. A dosage of 80 mg/Kg produced greater changes than a 120 mg/Kg dosage. The drug had no effect on the activity of catalase. Centrophenoxine also reduced lipofuscin deposits (studied both biochemically and histochemically) thus indicating that the drug inhibited lipofuscin accumulation by elevating the activity of the antioxidant enzymes. The data suggest that alleviation of senescence by centrophenoxine may, at least, partly be due to activation by it of antioxidant enzymes.

Aging↗
PubMed1983

Effects of antibiotics on polymorphonuclear leukocyte chemiluminescence and chemotaxis.

Polymorphonuclear leukocyte chemiluminescence and chemotaxis assays were performed on cells obtained from normal individuals and patients with defined defects in chemotaxis or chemiluminescence. After in-vitro pre-incubation with trimethoprim/sulphamethoxazole, its separate components, clindamycin and cefotaxime, normal cells showed some enhancement in chemotaxis and significant increase in chemiluminescence. There was an even more marked increase in chemotaxis when these antibiotics were incubated with cells from patients with leukocyte chemotaxic defects. When the cells from patients with chemiluminescence defects were pre-incubated with these antibiotics, there was also substantial enhancement in chemiluminescence.

Anti-Bacterial Agents↗
PubMed1983

Trend and types of disabled persons in Libyan Arab Jamahiriya.

Libyan Arab Jamahiriya pays special attention to the problem of disability. It truly follows the policy: "Full participation and equality for all persons with disability". In the country, the number and types of disabled persons have been documented thrice since 1964 and priority social services have been extended for them. The prevalence of disabled persons per 1000 population has shown a downward trend from 29.26 in 1964 to 18.65 in 1976. Males were observed to have significantly higher rates than females. The age specific disability rate per 1000 was 7.92 under 15 years, 24.23 between 15 to 49 years and 99.95 for 50 years or more. Blindness and paralysis were the first and second frequent causes of disability in the three counts carried out in 1964, 1973 and 1976. Among all causes of disability mental subnormality and loss of limbs respectively moved up from position five and four in 1964 to three and five in 1973 and 1976; whereas, deafness and dumbness together moved down from position three to four during the same period of time. Compared to the situation in 1964, all categories of disabled persons per 1000 population showed a declining trend over the years except of mentally subnormal who showed an increasing trend. The common causes of disability in the descending order of frequency were acquired diseases (both communicable and non-communicable), accidents, congenital and other disorders. Prevention of disability and services for disabled persons are outlined along with reference to the newly founded National Committee for Care to Disabled Persons.

Adolescent↗
PubMed1983

Transport and Metabolism of Sucrose versus Hexoses in Relation to Growth in Etiolated Pea Stem.

Sucrose, supplied to detached pea (Pisum sativum L. var Alaska) epicotyls through cut bases, supported better growth of apical tissue than supplied glucose and/or fructose. The hexoses were converted mainly to sucrose in basal regions of the epicotyl but some moved as such through the epicotyl and accumulated at the apex (plumule) at a rate faster than sucrose. A greater proportion of the carbon derived from supplied hexoses than from sucrose was used for synthesis of ethanol-insoluble products throughout the epicotyl. By use of asymmetrically labeled sucrose, it was shown that neither hexose moiety was used preferentially for the synthesis of metabolites. Supplied sucrose moved as such only up to the region of cell elongation where it was hydrolyzed and completely equilibrated before moving into more apical regions. The results indicate that better growth with supplied sucrose than hexose could not have resulted from differential effects on cell division, more rapid uptake or transport of sucrose, enhanced wall synthesis, or cleavage by sucrose synthase. It is concluded that transported sucrose versus hexoses must undergo or evoke different reactions which affect growth in the region of cell elongation.

Journal Article↗
PubMed1983

Onychomycosis.

Explore the source record for details and available documents.

Adolescent↗
PubMed1983

The immune status of Singapore children to hepatitis B virus.

In a cross-sectional survey of hepatitis B immune status, 458 consecutive children below the age of 12 years were studied. 37.3% of these children were positive for one of three markers, HBSAg, anti-HBS or anti-HBC. 15.5% were positive for two and 1.3% were positive for all three. 10.9% were positive for HBSAg, 27.8% for anti-HBC and 19.6% for anti-HB2. The males showed a higher HBSAg carrier rate than the females, 13.5% and 6.8% respectively. This difference was significant (p less than 0.05). This study confirmed that the Singaporeans were exposed to hepatitis B virus infection from very early in life and in order to prevent the infection, immunisation should be considered in early childhood.

Antibodies, Viral↗
PubMed1983

Changes in hexokinase isoenzymes in regions of rat brain during insulin-induced hypoglycemia.

Activities of hexokinase isoenzymes were determined during insulin-induced hypoglycemia in soluble and total particulate fractions from three regions of rat brain. Type I hexokinase isoenzyme activity showed a small decrease in both soluble and particulate fractions from the cerebral hemispheres. In cerebellum and brain stem, however, Type I isoenzyme showed a decrease only in the soluble fraction. A significant increase was observed in hexokinase Type II isoenzyme from both the fractions, in all the three brain regions 1 h after insulin administration.

Animals↗
PubMed1983

Chemosterilization and its reversal in the snail Lymnaea acuminata.

Treatment of the snail Lymnaea acuminata, the vector for the liver flukes Fasciola hepatica and Fasciola gigantica, with two alkylating agents (cyclophosphamide and busulfan) and one thiocarbamide (thiourea) caused reduction in the number of eggs and production of non-viable embryos. All the three drugs caused reduction in the levels of DNA, RNA and protein and the activity of alkaline phosphatase in the gonadal tissues of this snail. There was enhancement in free amino acid levels and activity of acid phosphatase by these drugs. Discontinuation of treatment could not reverse the cytotoxic effects of these drugs. Treatment of sterilized snails with prostaglandin E1 (PGE1), prostaglandin F2 alpha (PGF2 alpha) or hydrogen peroxide not only restored the number of eggs but also caused full embryonic development. Also, there was near total recovery of RNA, DNA and protein levels and small changes in free amino acid levels as well as the activity of alkaline and acid phosphatase. It has been suggested that the prostaglandins play a modulatory role in protein synthesis. The possible therapeutic use of PGE1, PGF2 alpha and H2O2 has been pointed out.

Alprostadil↗
PubMed1983

Alpha 1-antitrypsin phenotypes in Canadian Metis.

Alpha 1-antitrypsin phenotyping was performed on serum of 344 Metis living in an isolated northern Saskatchewan community. Only PiM and PiMZ phenotypes were observed with phenotype frequencies of 98.5 and 1.5 respectively. Gene frequencies were 0.993 for PiM and 0.007 for PiZ. The low frequency of non-M phenotypes is similar to that in another population of North American natives, the Eskimos of Igloolik as well as Finnish and Norwegian Lapps.

Canada↗
PubMed1983

Effect of medroxyprogesterone acetate on the digestive and absorptive functions of rat intestine.

The effects of medroxyprogesterone acetate (MPA) on the digestive and absorptive functions of the small intestinal epithelium have been investigated in female albino rats. The transport of sodium-dependent glucose was significantly enhanced while sodium-independent transport remained unaltered in drug-treated animals. The uptake of amino-acids was also considerably increased, while Ca++ uptake decreased significantly on administration of the drug at a dose of 35 mg/kg body weight once a week for 1 month. Kinetic studies of glucose transport in the presence of sodium ions revealed that MPA treatment affected the rate of uptake of glucose by elevating Vmax, but the Km value remained the same in treated and untreated animals. The administration of the drug also led to significant augmentation in the activities of the brush border enzymes, disaccharidases, and to an insignificant decrease in alkaline phosphatase. The activities of leucine aminopeptidase did not show any change. The enhancement in sucrase activity might be due to induction of the enzyme because only Vmax was elevated in treated animals. As concerns cellular enzymes, lactate dehydrogenase activity was significantly depressed. This study suggests that MPA also exerts glucocorticoid-like effects on the intestinal tissue.

Amino Acids↗
PubMed1983

Ventricular fibrillation in acute myocardial infarction.

Ventricular fibrillation (VF) developed in 7.42% patients with acute myocardial infarction (AMI). It was more frequent among patients with anterior myocardial infarction compared to inferior myocardial infarction. On the basis of sequence of events, cases of ventricular fibrillation (VF) were classified in to Primary (P), Secondary (S) and Agonal (A). 57.69% cases had SVF, 30.76% had AVF and only 11.53% cases had PVF. In all cases of PVF, ECG was normal prior to the development of VF and developed abruptly without any warning.

Adult↗