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Biomedical subjects

N Nath

Publications and source records attributed to N Nath.

At least 109 records · Page 6Linked to original sources
PubMed1977

Hepatitis B e antigen and antibody activity in hepatitis B virus infection.

Groups of institutionalized subjects, volunteer blood donors with serologic evidence of asymptomatic hepatitis B virus infection, and patients with acute type B viral hepatitis were studied for the presence of hepatitis B e antigen and antibody in a sequential manner over a period of two to three years. HBeAg was detected in 9.5% of institutionalized residents and volunteer blood donors and in 24% of patients with acute type B viral hepatitis. HBeAg positive subjects frequently had persistently elevated pyruvic glutamic transaminase levels in the serum. Anti HBe activity was observed in 26 to 32% of subjects positive for hepatitis B surface antigen. Long-term follow-up indicated that HBsAg positive subjects with anti HBe did not eventually become seronegative for HBsAg.

Adolescent↗
PubMed1977

Seroepidemiology of hepatitis B virus in Israel. Results of a pilot study in Jerusalem.

One thousand thirty-three native and immigrant Israelis, divided into 10-year age groups, were tested for the hepatitis B surface antigen (HBSAg) and antibody (anti-HBS). The prevalence of anti-HBS was 10.1%, increasing with age from the first (6.3%) through the fifth decade (16.2%) and declining slightly in the sixth and seventh decades. The age-adjusted prevalence of anti-HBS was higher for native Arabs (20.8%) compared with native Jews (4.8%), and for immigrants from North Africa (33.3%), compared with immigrants from the Middle and Near East (20.1%) and Western ("Ashkenazi") countries (8.5%). Acquisition of anti-HBS was not correlated with a past history of jaundice or of blood transfusion. Of the positive sera reactive for anti-HBS that were subtypable, 74% were anti-y and 26%, anti-d specific. The prevalence of HBSAg for the study population was 1.8%, resulting in a prevalence of hepatitis B virus (HBV) infection, past and present, of 11.9%. These findings indicate that, while HBV infection is prevalent in Jerusalem, the most common presentation is a non-icteric illness with an age distribution extending through early adulthood and not coinciding with the early childhood clustering characteristic of icteric hepatitis in the region. The serologic findings are consistent with other clinical and epidemiologic evidence that endemic hepatitis in Jerusalem is predominantly the result of infection by "non-B" viruses.

Adolescent↗
PubMed1977

Growth profile of preschool children from an urban low socio-economic community in India.

A five years longitudinal study on the growth and development was carried out on 68 infants from a low-socio-economic urban community in India. Ninety four percent of them suffered from Protein Calorie Malnutrition of varying degree at some time or the other during their first six years and of them 30% suffered severe PCM. The effect on heights and head circumference followed the same pattern as body weight. Their developmental quotients correlated with the degree of PCM till age of four years. This observation brings into focus a growth profile of underprivileged toddlers which is far worse than what is brought out by cross sectionals surveys. The family at greatest risk is one with a young mother who is ill equipped with the techniques of successful breast feeding and supplemental feeding of her infant. Additional factor is early onset of diarrhoeal illnesses in these children. It is suggested that such a vulnerable family requires special support from the health delivery system planned for urban communities.

Adult↗
PubMed1976

Purification of hepatitis B surface antigen using polyethylene gylcol, pepsin and Tween 80.

A simple, inexpensive procedure for the isolation and purification of HB8Ag from plasma is described. The technique included precipitation of HBsAg with PEG and elimination of normal plasma proteins by digestion with pepsin. Tween 80 was used to remove contaminating lipoprotein(s). This technique resulted in about a 200-fold gain in the specific activity of HBsAg and yielded about 20-40% recovery. Rabbits immunized with the purified antigen produced type-specific antibodies to HBsAg without detectable reactivity to normal human plasma antigens.

Animals↗
PubMed1976

Platelet antiplasmin: its extrusion during the release reaction, subcellular localization, characterization, and relationship to antiheparin in pig platelets.

Antiplasmin activity was shown to be released from washed pig platelets by thrombin following a time course similar to that of 3H-serotonin. Antiheparin activity (platelet factor 4) appeared to be released by thrombin at a slower rate than 3H-serotonin or antiplasmin activity. Subcellular fractionation of pig platelets showed that the storage site for antiplasmin is probably the dense (amine storage) granules. Antiheparin was distributed among all of the subcellular particulate fractions except the fraction rich in dense granules. Material released from washed pig platelets and concentrated by ZnSO4 precipitation (crude antiheparin) was found to be rich in antiplasmin activity. Gel filtration on Sephadex G-150, DEAE cellulose column chromatography, and polyacrylamide gel electrophoresis showed that pig platelet antiplasmin is a low molecular weight (approximately 30,000 d) material of alpha1-globulin electrophoretic mobility. It was found to be heat labile and also inhibitory to the caseinolytic activity of trypsin but had no effect on the action of thrombin on fibrinogen. These data indicate that platelet antiplasmin is distinct from platelet antiheparin.

Animals↗
PubMed1975

Efficacy of hepatitis B immune serum globulin after accidental exposure. Preliminary report of the Veterans Administration Cooperative Study.

A randomised, double-blind, controlled trial has been undertaken to compare the efficacy of hepatitis B immune globulin (H.B.I.G.) with that of immune serum globulin (I.S.G.) for the prophylaxis of viral hepatitis. Participants in the trial were individuals exposed accidentally to material infectious for hepatitis (primarily viral B hepatitis). Preliminary evaluation of the first 302 of the 561 individuals entered into the study indicates that H.B.I.G. significantly reduced the frequencies of both clinical and subclinical hepatitis during the first 3--4 months after the injection. Less than 10% of H.B.I.G. recipients had detectable anti-HBs at the sixth month after the injection, suggesting that H.B.I.G. might need to be given every 3--4 months to continually exposed individuals. Further long-term evaluation is required in order to define more clearly those most likely to benefit from H.B.I.G.

Clinical Trials as Topic↗
PubMed1975

ADP, thrombin, and Bothrops atrox thrombinlike enzyme in platelet-dependent fibrin retraction.

Clots formed upon the addition of thrombin to human platelet-rich plasma (PRP) retracted readily but the clotting enzyme from Bothrops atrox venom did not cause retraction in PRP unless ADP, collagen, epinephrine, or low concentrations of thrombin (0.1 U) were added. The latter type of retraction was inhibited by apyrase and creatine phosphate kinase in the presence of creatine phosphate, but that induced with higher concentration of thrombin (2 U) was not. In a system composed of washed human platelets and purified fibrinogen, Bothrops marajoensis (BM) thrombinlike enzyme (highly purified preparations of viper venom) did not cause clot retraction. Addition of ADP to the platelet-fibrinogen mixture prior to BM enzyme resulted in stimulation of clot retraction that could be dissociated from the release of platelet constituents. Addition of low concentrations of thrombin (0.1 U/ml) caused retraction associated with a considerable release of adenine nucleotides that was inhibited by potato apyrase. Electron micrographs showed platelet-fibrin aggregates in all types of retracted clots. Nonretracted clots formed in the presence of potato apyrase contained discoidal platelets that were not in close association with fibrin. It has been postulated that platelet-dependent fibrin clot retraction induced by collagen, epinephrine, and low concentration of thrombin is mediated by ADP. High concentrations of thormbin may possibly promote clot retraction independently of ADP.

Adenosine Diphosphate↗
PubMed1975

Inihibition of human platelet aggregation by dipyridamole and two related compounds and its modification by acid glycoproteins of human plasma.

The inhibitory effect of dipyridamole (RA 8) and its two derivatives (RA 233 andSH 869) on platelet aggregation in platelet-rich plasma (PRP) AND IN SUSPENSIONSOF WASHED PLATELETS WAS EVALUATED USING 3 AGGRESSING STIMULI: ADP, thrombin, and collagen. Mean effective dose (ED'30) of RA 8 causing 50 percent inhibition of plateletaggregation of washed human platelets by ADP, collagen, or thrombin varied from 1.2 x 10'-7 to 1.8 x 10'-7M. On the other hand, RA 8 caused little inhibition aggregation in human PRP. RA 233 and SH 869 produced similiar degrees of inhibition ofplatelet aggregation in human PRP and in suspensions of washed human platelets.Platelet-poor plasma, fraction VI-acid glycoproteins, or purified alpha'1-acid glycoprotein complex was isolated by means of Sephadex G-25 gel filtration. It is postulated that the formation of this complex leads to the blocking of the capacity of RA 8to inhibit platelet aggragation. RA 233 and SH 869 had little capacity to form complexes with acid glycoproteins of human plasma. This may explain the effectiveness of these compounds in inhibiting platelet aggregation in PRP.

Adenosine Diphosphate↗
PubMed1975

Antigenic and antiheparin properties of human platelet factor 4 (PF4).

Platelet factor 4 (PF4, a heparin-neutralizing protein) was isolated from washed human platelets. It was found to be homogenous by SDS-polyacrylamide gel electrophoresis, immunodiffusion, and immunoelectrophoresis, when tested with monospecific antibody produced in rabbits. PF4 is a heat-stable protein, but its antiheparin activity and antigenicity are destroyed by trypsin. The molecular weight of PF4 as calculated by amino acid analysis is approximately 8000 and by SDS-polyacrylamide gel electrophoresis with beta-mercaptoethanol, 7100 daltons. PF4 migrated to the cathode at pH 8.6. The interaction of PF4 with heparin resulted in the formation of a complex which migrated to the anode, as tested by immunoelectrophoresis. Incubation of purified PF4 with its antibody at 37 degrees C resulted in a loss of antiheparin activity. The presence of antiheparin activity and of PG4 antigen in material released during platelet aggregation by various agents and at various stages of the preparative procedure closely correlated. It has been concluded that PF4 antigen and antiheparin activity are two properties of the same protein. Comparison of human and pig PF4 revealed significant biochemical and antigenic differences.

Amino Acids↗