PubMed Health⌕ Search

Biomedical subjects

D Nath

Publications and source records attributed to D Nath.

34 records · Page 2Linked to original sources
PubMed1995

The amino-terminal immunoglobulin-like domain of sialoadhesin contains the sialic acid binding site. Comparison with CD22.

Sialoadhesin and CD22 are members of a recently characterized family of sialic acid-dependent adhesion molecules belonging to the immunoglobulin superfamily. Sialoadhesin is a macrophage-restricted receptor containing 17 extracellular Ig-like domains which recognizes oligosaccharides terminating in NeuAc alpha 2-3Gal in N- and O-linked glycans. CD22 is a B cell-restricted receptor with seven Ig-like domains which selectively recognizes oligosaccharides terminating in NeuAc alpha 2-6Gal in N-glycans. Sequence similarity between these proteins is highest within their first four amino-terminal Ig-like domains. Here we identify the domain(s) containing the binding sites of both molecules by generating a series of extracellular domain deletion mutants fused to the Fc portion of human IgG1. Binding activity was analyzed by solid phase cell adhesion assays and also by surface plasmon resonance using purified glycophorin and CD45 as ligands for sialoadhesin and CD22, respectively. For sialoadhesin, the amino-terminal V-set Ig-like domain was both necessary and sufficient to mediate sialic acid-dependent adhesion of the correct specificity. In contrast, for murine CD22, only constructs containing both the V-set domain and the adjacent C2-set domain were able to mediate sialic acid-dependent binding. These results are consistent with the sialic acid binding site for both proteins residing in the membrane distal V-set domain, but for CD22 a direct contribution in binding from the neighboring C2-set domain cannot be excluded.

Amino Acid Sequence↗
PubMed1994

X-ray kinematography as a tool for investigations of distal limb movements of the cat.

X-ray kinematography was used to investigate the kinematics of cat distal forelimb joints during motor behaviour. These joints are not accessible for instrumentation with external markers normally used in conventional motion analysis systems. To trace the movements in space two X-ray systems positioned rectangularly to each other illuminated the forelimb quasi-simultaneously with pulsed X-ray shots (time resolution: 20 ms). A mathematical model was developed for 3-dimensional reconstruction of the object and includes procedures for correction of image distortions, e.g., pincushion distortions and rotation of the image due to interaction of the earth's magnetic field with the electron optics of the image amplifiers. Accuracy of image correction and object reconstruction is +/- 1 pixel, corresponding to +/- 0.5 mm in space which is sufficient for investigation of the kinematics of cat distal forelimb joints. The approach described is of general relevance and useful in kinematic investigations where the structures under study are not directly accessible to external instrumentation with markers.

Animals↗
PubMed1994

The impact of marketing on hospital performance.

This study examines the effect of traditional and innovative marketing factors on the overall financial, operations and market performance of 71 not-for-profit hospitals in a metropolitan area. Traditional marketing factors of location, services offered and pricing did influence the financial performance of system-affiliated and non-system hospitals. They also influenced the operating performance of urban hospitals and the market performance of non-teaching institutions. In contrast, the innovative marketing factors of physician relations, community relations and specialized sales forces had no significant influence on performance differences among the hospitals in the entire sample and sub-samples based on geography, teaching involvement and system affiliation.

Community-Institutional Relations↗
PubMed1993

Attenuation of myocardial reperfusion injury by reducing intracellular calcium overloading with dihydropyridines.

The effects of three different dihydropyridine (DHP) calcium channel antagonists, nisoldipine, nimodipine, and nifedipine, on myocardial ischemic and reperfusion injury were studied using isolated rat hearts subjected to ischemia and reperfusion. Hearts were perfused with Krebs-Henseleit bicarbonate buffer containing 0, 4, 16, 64 and 100 nM concentrations of the above dihydropyridines for 15 min. Global ischemia was then induced by terminating the aortic flow for 30 min at 37 degrees, followed by 30 min of reperfusion. Left ventricular (LV) functional (LV developed pressure, its first derivative and coronary flow) and biochemical parameters (creatine kinase release) were monitored prior to ischemia and during reperfusion. In separate group of hearts, intracellular free Ca2+ ([Ca2+]i) was monitored with an intracellular calcium analyzer using a fluorescent Ca2+ indicator (Fura-2 AM). Tissue Ca2+ was also measured by atomic absorption spectroscopy after perfusing the hearts with ion-free cold buffer to wash out extracellular Ca2+. Significant recovery of the coronary flow was observed in all hearts treated with a high concentration (100 nM) of DHPs compared with the control group (P < 0.05), while a lower dose of nisoldipine (16 nM) and nifedipine (64 nM) also improved the coronary flow effectively. Reduction of myocardial creatine kinase release and improvement of the recovery of LV developed pressure, dp/dtmax, were achieved by DHPs in a concentration-dependent manner. A higher concentration of DHPs also decreased the formation of myocardial thiobarbituric acid reactive substances, although these compounds did not possess direct free radical scavenging effects in vitro. Tissue Ca2+ content was reduced significantly in treated groups. The rise of [Ca2+]i during ischemia and reperfusion appeared to be attenuated by these DHPs. The concentration-response study of the three DHPs showed the effective concentrations for reducing [Ca2+]i to be 16, 64 and 100 nM nisoldipine, nifedipine and nimodipine, respectively, in this experimental setting. The above results indicate that pretreatment with DHPs can attenuate the myocardial reperfusion injury by modulating Ca2+ overloading and decreasing the susceptibility of the membrane to free radical attack.

Animals↗
PubMed1993

Health care clusters in hospitals: the market audit and frameworks for planning.

Many hospitals are turning to cluster relationships to gain the benefits of diversification without the troubles of increased capital costs and management conflicts. The goal of healthcare clusters is to provide a continuum of care to a defined geographic region through integration of referral and payment systems. To aid in successful planning for healthcare clusters, a market audit and frameworks for examining the current healthcare market are presented.

Catchment Area, Health↗
PubMed1992

Commonly used Indian abortifacient plants with special reference to their teratologic effects in rats.

A survey programme was organised in Lucknow and Farrukhabad, two towns of Uttar Pradesh, from March 1987 to July 1987. During the survey, the common folk medicine plants used by women were recorded and Ayurvedic and Unani drug encyclopedias were consulted for the antireproductive potential of these plants. Aqueous or 90% ethanol extracts of the plants of interest were studied in rats orally dosed for 10 days after insemination with special reference to effects on foetal development. Leaf extracts of Moringa oleifera and Adhatoda vasica were 100% abortive at doses equivalent to 175 mg/kg of starting dry material. Only the flowers of Acacia arabica and Hibiscus rosa-sinensis appeared to lack teratologic potential at the doses tested.

Abnormalities, Drug-Induced↗
PubMed1992

Macrophages in tissues and in vitro.

Macrophages have specialized functions in different tissue microenvironments such as lymphohaemopoietic organs and the nervous system. Recently, progress has been made in defining cellular and molecular properties of isolated and tissue macrophages in the developing and adult animal.

Animals↗
PubMed1991

Preclinical toxicity study of a male injectable antifertility agent (styrene maleic anhydride) in rhesus monkeys, Macaca mulatta.

Polymer styrene maleic anhydride dissolved in dimethyl sulphoxide was injected intravasally to rhesus monkeys at the dose levels of 100 mg, 250 mg, and 500 mg in each vas deferens in low, high, and highest dose groups respectively, while control group received 0.5 ml DMSO in each vas deferens. The systemic toxicity study of the implant was carried out for 90 d. There had been no alteration in any of the toxicity parameters, ie, body weight, haematological, biochemical or histopathological, in the test animals as compared to control animals. Hence, it is concluded that the polymer SMA injected at above doses appears to be safe in our experiment.

Animals↗
PubMed1990

Long-term toxicity studies of styrene maleic anhydride in rats.

In male Charles Foster rats, polymer styrene maleic anhydride was injected into the lumen of the vas deferens at dose levels of 1.0, 2.5, and 5.0 mg in each vas deferens of Groups II, III, and IV, respectively, while controls (Group I) received 0.03 ml dimethyl sulfoxide in each vas deferens. The rats were observed for 6 months for toxicity. No change in any of the toxicity parameters in test animals as compared to controls was revealed. Hence, the polymer is safe at the doses used within 6 months of injection.

Animals↗
PubMedDate not supplied

Purification and characterization of a protein kinase from goat sperm plasma membrane.

A protein kinase that causes phosphorylation of serine and threonine residues of casein has been partially purified from goat cauda-epididymal sperm plasma membrane and characterized. The kinase, solubilized from the membrane with 1.0% Triton X-100, was purified to 480-fold by using DEAE-cellulose and casein-Sepharose affinity chromatographic techniques. The kinase is a strongly basic protein with pI of 9.5. The enzyme has a molecular mass of 310 kilodaltons as estimated by Sephacryl S-300 gel exclusion. The kinase showed affinity for protein substrates in the order membrane proteins > casein > phosvitin > histone > protamine. The apparent Km values of the kinase for casein and membrane proteins were 1 and 0.15 mg/mL, respectively. The synthetic peptides Kemptide and poly(Glu80Tyr20) did not serve as substrates of the enzyme. ATP, rather than GTP or PP(i), is the donor of phosphate for the phosphorylation reaction. Cyclic AMP and GMP, NaCl (0.25 M), KCl (0.25 M), Ca2+, calmodulin, phosphatidylserine, and muscle protein kinase inhibitor had no appreciable effect on the kinase activity. Heparin (0.5 microgram/mL) showed high affinity for inhibiting only 40% of the kinase activity, whereas polyamines at a relatively high concentration (5 mM) inhibited 40-50% of the enzymic activity. The kinase appears to be distinct from other protein kinases including casein kinases. The activity of the kinase derived from the purified sperm plasma membrane was markedly (approximately 90%) lost when the intact spermatozoa were pretreated with diazonium salt of sulfanilic acid, a membrane nonpenetrating surface probe.(ABSTRACT TRUNCATED AT 250 WORDS)

4-Chloromercuribenzenesulfonate↗
PubMedDate not supplied

Teratological evaluation of an injectable male antifertility agent, styrene maleic anhydride, in rats.

Polymer styrene Maleic anhydride (SMA) dissolved in dimethylsulphoxide (DMSO) was injected into the lumen in each vas deferens of male rats at dose levels of 0.25 mg, 0.50 mg, 1.0 mg, 2.5 mg, and 5.0 mg, while control rats (groups 1) received 0.03 mL DMSO in each vas deferens. After 4 weeks, the lumen was flushed with 0.1 mL DMSO and the animals were left for another 6 weeks to regain fertility. These rats were mated with virgin and coeval females. No anomaly was observed which could be related to teratogenic action of the polymer in pregnant mothers or fetuses.

Abnormalities, Drug-Induced↗