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Biomedical subjects

S Gupta

Publications and source records attributed to S Gupta.

At least 1,405 records · Page 78Linked to original sources
PubMed1987

Efficacy of a substituted methyl benzimidazole carbamate against developing and adult helminth parasites.

The efficacy of a substituted methyl benzimidazole carbamate, methyl 5(6)-[4-N-(2-pyridyl)] piperazino carbamoyl benzimidazole-2-carbamate, was assessed against larval and adult forms of Ancylostoma ceylanicum (hookworm), Nippostrongylus brasiliensis (trichostrongylid), Hymenolepis nana (tapeworm) and Brugia malayi (filariid) in experimentally-infected animals. The compound was found to have high efficacy against the developing stages (L3, L4, L5) of A. ceylanicum in hamsters at a single dose of 12.5 mg kg-1, against larvae of N. brasiliensis at 17.5 mg kg-1 and against cysticercoids of Hymenolepis nana at 100 mg kg-1 daily for 3 days given per os (p.o.) or intraperitoneally (i.p.). All the stages of B. malayi in Mastomys were killed when the compound was given i.p. at a dose of 6.25 mg kg-1 for 5 consecutive days. A dose of 6.25 mg kg-1 eliminated all adult A. ceylanicum from infected hamsters, 100 mg kg-1 resulted in complete removal of Syphacia obvelata adults from 63.6% of infected mice, 25 mg kg-1 X 5 dose eliminated 100% of adult B. malayi from infected Mastomys and a single 50 mg kg-1 dose expelled all H. nana adults from infected rats.

Ancylostoma↗
PubMed1987

Alkaline phosphatase as a model for studying metal-protein interactions in pulmonary toxicity.

An attempt has been made to study the biochemical properties of lung alkaline phosphatase so that it may serve as a model for measuring the toxicity of air pollutants, especially metals. Lung was shown to be a better source of this enzyme in comparison to other organs in rats. The optimum pH, metal requirements, substrate specificity, and affinity constants were characterized with different substrates, and the effect of different metals was studied. The involvement of zinc in the lung enzyme was not indicated as shown by Sephadex G-200 elution profile of postmitochondrial supernatant of 65Zn-treated animals.

Alkaline Phosphatase↗
PubMed1987

Physiological stress induced by sublethal concentrations of phenolic compounds in Notopterus notopterus: measurement of hydrolytic enzymes.

The studies on the effects of phenol (P), 2,4-dinitrophenol (DNP), pentachlorophenol (PCP) individually and in three combinations, viz., (PCP + DNP)/P (highly antagonistic), (DNP + P)/PCP (additive), and (P + DNP)/PCP (highly synergistic), at three sublethal levels (1/10, 1/15, and 1/20 of the 96-hr LC50) on the activity of hydrolytic enzymes (acid, alkaline, and glucose-6-phosphatases and 5-nucleotidase) in the brain and kidney of a fresh-water teleost, Notopterus notopterus revealed inhibition of enzyme activity after 15 and 30 days of exposure. Maximum inhibition (-89.32%) was observed in acid phosphatase activity in brain at 1/10 concentration of (P + DNP)/PCP combination after 30 days, but minimum (-3.64%) in activity of glucose-6-phosphatase in kidney at 1/20 of (PCP + DNP)/P combination after 15 days of exposure. However, biphasic effects of P, DNP, and (PCP + DNP)/P combination were observed in kidney, i.e., inhibition of enzymes activity at higher concentrations and stimulation at lower concentrations after both time intervals.

5'-Nucleotidase↗
PubMed1987

Amino acid metabolism in Ancylostoma ceylanicum and Nippostrongylus brasiliensis.

Ancylostoma ceylanicum and Nippostrongylus brasiliensis decarboxylated most of the amino acids examined, but only a few at significant rates. The former nematode in general possessed higher activities. Striking differences between the two parasites were, however, noticed regarding the metabolism of some of the amino acids. For instance, while alanine followed by aspartate produced highest amounts of 14CO2 in the presence of A. ceylanicum, proline exhibited maximum decarboxylation in case of N. brasiliensis. Tyrosine and lysine, on the other hand, did not liberate detectable CO2 with either parasite. Likewise, although large number of amino acids underwent transamination with 2-oxoglutarate, only some of them elicited appreciable activity for any of the two parasites.

Amino Acids↗
PubMed1987

Natural killer cell and islet killer cell activities in human type 1 diabetes.

Peripheral blood mononuclear cells from 14 type 1 diabetic patients were examined for natural killer cell activity using the K562 cell line as 51Cr labeled targets. Mean cytotoxicity of K562 cells by unseparated mononuclear cells derived from new onset type 1 patients (12 +/- 1.6%) was lower (P less than .01) than that observed in non diabetic controls, (25 +/- 4.2%). Mean natural killer cell cytotoxicity mediated by enriched non-T cells from patients (41 +/- 5.8%) was also lower (P less than 0.03) than in the control group (56 +/- 3.7%). Specificity of these findings was evaluated by also examining other diabetic patient subgroups. Mean non T cell mediated natural killer cell activity in type 2 diabetic patients and type 1 patients with long term disease was 65 +/- 5.4% and 62 +/- 4.8% respectively (p less than 0.001 vs new onset type 1 patients). Longitudinal studies of new onset type 1 patients during the remission (honeymoon) phase revealed no improvement of impaired natural killer cell activity. In 30 new onset and 11 remission diabetic patients, mean non-T cell-mediated cytotoxicity was also measured using dispersed 51Cr labeled pancreatic islet target cells. Mean islet cytotoxicity mediated by cells from new onset patients was 34 +/- 2.4%, whereas in nondiabetic control subjects mean cytotoxicity was 25 +/- 1.8% (p less than 0.005). During remission, islet cytotoxicity returned to normal values in over half of the patients. There was no correlation between K562 and islet cell cytotoxicity in either of the latter two patient groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1987

Genomic RNAs of influenza viruses are held in a circular conformation in virions and in infected cells by a terminal panhandle.

The viral RNA segments in influenza virions were shown to be circular in conformation by using psoralen crosslinking methods. Electron microscopy of purified RNA following treatment of virus with the psoralen reagent 4'-aminomethyltrioxsalen (AMT) revealed circles with lengths corresponding to the individual segments. RNA blot analysis using polyacrylamide gels demonstrated that RNA from AMT-treated virus had a slowed migration, consistent with it being a single-stranded circle. Furthermore, nuclease S1 protection assays indicated that the termini of the RNA segments form an approximately 15-base-pair-long panhandle. This structure is consistent with the partial sequence complementarity that has been observed for the termini of all influenza virus RNAs. By RNA blot analysis, circular structures of viral sense RNA were also found in influenza virus-infected cells at early and late time points. The circular RNA was the predominant species at the time when the major transcription product is message RNA. This finding and the observation that the termination signal for mRNA synthesis directly abuts the panhandle suggest that a panhandle in the template viral RNA is a cis regulatory signal promoting the synthesis of mRNA instead of plus-sense template. Also, since the panhandle is present in high concentration in virions, we suggest that it is required for packaging and that the input RNA after infection is in the proper conformation for synthesis of primary transcripts.

Cross-Linking Reagents↗
PubMed1987

Ancylostoma ceylanicum: migratory behaviour in golden hamsters after oral and parenteral infection.

The infectivity and migratory pattern of Ancylostoma ceylanicum infective larvae (L3) were investigated in hamsters infected by various routes. Following oral administration 40-70% of L3 attained maturity and there was no tissue migration. Following subcutaneous inoculation a small number (1-1.2%) of L3 attained maturity in the intestine after completing the broncho-oesophageal journey. Larvae which penetrated the skin also became adult in the intestine. Most of the larvae entering parenterally remained at the site of infection and in the tracheal region for more than 100 days without undergoing any development, other than desheathment. Those transmitted orally to naive hamsters developed in the normal way. Larvae inoculated parenterally into female hamsters were able to infect offspring in milk, but could not cross the placental barrier.

Administration, Oral↗
PubMed1987

Two types of potassium channels in murine T lymphocytes.

The properties of two types of K+ channels in murine T lymphocytes are described on the basis of whole-cell and isolated-patch recordings using the gigohm-seal technique. Type l (standing for "lpr gene locus" or "large") channels were characterized mainly in T cells from mutant MRL/MpJ-lpr/lpr mice, in which they are present in large numbers. Type n ("normal") K+ channels are abundant and therefore most readily studied in concanavalin A-activated T cells from four strains of mice, MRL-+/+, CBA/J, C57BL/6J, and BALB/c. Type l channels, compared with type n, are activated at potentials approximately 30 mV more positive, and close much more rapidly upon repolarization. Type l channels inactivate more slowly and less completely than type n during maintained depolarization, but recover from inactivation more rapidly, so that little inactivation accumulates during repetitive pulses. Type l channels have a higher unitary conductance (21 pS) than type n (12 pS) and are less sensitive to block by external Co++, but are 100-fold more sensitive to block by external tetraethylammonium (TEA), with half-block of type l channels at 50-100 microM TEA compared with 8-16 mM for type n. TEA blocks both types of channels by reducing the apparent single channel current amplitude, with a dose-response relation similar to that for blocking macroscopic currents. Murine type n K+ channels resemble K+ channels in human T cells.

Animals↗
PubMed1987

Mitogen induction of ion channels in murine T lymphocytes.

Using gigohm-seal recording, we studied ion channel expression in resting and activated T lymphocytes from mice. Both the number of channels per cell and the predominant type of K+ channel depend upon the state of activation of the cell. Unstimulated T cells express small numbers of K+ channels, typically a dozen per cell, and are heterogeneous, usually expressing either type n or type l K+ channels (see DeCoursey, T. E., K. G. Chandy, S. Gupta, and M. D. Cahalan. 1987. Journal of General Physiology. 89:379-404). 1 d after stimulation by the murine T cell mitogen concanavalin A, large numbers of type n K+ channels appear in enlarged, activated cells. Type n channels appear in activated cells with a time course consistent with that reported for mitogen-induced enhancement of protein synthesis. Voltage-gated tetrodotoxin-sensitive Na+ channels present in about one-third of unstimulated cells from the MRL-n strain are increased approximately 10-fold after activation.

Animals↗
PubMed1987

Upper endoscopy for occult bleeding in renal failure.

We studied 41 patients with renal failure prospectively to assess the value of upper gastrointestinal endoscopy in detecting occult bleeding after an abrupt fall in hemoglobin (Hb) level. Thirty-four patients were on maintenance dialysis, six on plasma exchange, and one on dialysis and plasma exchange. At gastroscopy two patients (4.9%) had bleeding lesions, five patients (12%) peptic ulcers without bleeding, and 18 patients (44%) mild esophagitis, gastritis, or duodenitis. Although mucosal abnormalities in the upper gastrointestinal tract were common, clinically inapparent gastrointestinal bleeding was only rarely responsible for sudden changes of Hb in these patients.

Adolescent↗
PubMed1987

Comparison of ultrasonography, computed tomography and 99mTc liver scan in diagnosis of Budd-Chiari syndrome.

Ultrasonography, computed tomography and 99mTc liver scanning are all useful in diagnosis of patients with the Budd-Chiari syndrome. In a study to determine their comparative value characteristic findings were recorded in all nine patients at ultrasonography and in seven patients at computed tomography. In contrast 99mTc liver scan showed a characteristic pattern in only one of eight patients. In our experience intrahepatic venous abnormalities were seen better at ultrasonography than at computed tomography. In addition, abnormality in the direction of blood flow could be detected by pulsed Doppler examination. Ultrasonography is relatively inexpensive, readily accessible, does not require administration of radiation or contrast agents and therefore should be the primary non-invasive investigation of patients with Budd-Chiari syndrome, or those at risk of developing it.

Adult↗
PubMed1987

Evaluation of enzymes in serum and cerebrospinal fluid in cases of cerebrovascular accidents.

Gamma glutamyl transpeptidase (GGTP), glutamic oxaloacetic transaminase (GOT), and glutamic pyruvic transaminase (GPT) were measured serially in the serum and cerebrospinal fluid (CSF) of 22 patients with fresh stroke and an equal number of age- and sex-matched healthy control subjects. It was observed that levels of these enzymes in the CSF of control subjects were very low but were significantly elevated (p less than 0.001) in both serum and CSF in patients with stroke. The elevation was greater in the CSF than in the serum and was maximum during the first four days of stroke. Thereafter, the enzymatic activity declined. Of all these enzymes, GGTP in CSF correlated best with the clinical picture. It was possible to differentiate between the ischemic and hemorrhagic type of stroke on the basis of CSF levels of GGTP (greater than 60.0 units in hemorrhagic stroke). There was no correlation between GGTP levels in CSF and serum or among GOT, GPT, and GGTP in CSF. It can be concluded, therefore, that estimation of GGTP in CSF is helpful not only in predicting the degree of cerebral damage and functional outcome of the patient following stroke but also in differentiating the type of stroke.

Alanine Transaminase↗
PubMed1987

Transplanted isolated hepatocytes: effect of partial hepatectomy on proliferation of long-term syngeneic implants in rat spleen.

Proliferation of isolated hepatocytes in long-term splenic implants was assessed by flash labelling with a 1 pulse of tritiated thymidine (3H TdR). Cell kinetics showed that the basal labelling index was 0.9% which was greater than normal non-regenerating liver. Twenty four hours following partial hepatectomy the labelling index was 2.0%, a significant rise. These results suggest that hepatocytes transplanted to the spleen constitute a suitable model for screening putative hepatotrophic factors, and are of relevance in establishing clinically useful models of hepatocyte transplantation.

Animals↗
PubMed1987

Polyamine metabolism as a target for growth inhibition of Acanthamoeba culbertsoni.

Alpha-difluoromethylornithine had no inhibitory effect on the growth of Acanthamoeba culbertsoni, while methylglyoxal bis(guanyl-hydrazone) and sinefungin completely blocked amebic growth at 2.5 mM and 5 micrograms/ml concentrations, respectively. Cyclohexylamine caused only partial inhibition of amebic growth at 50-200 microM concentrations. Methylglyoxal bis(guanyl-hydrazone) inhibited S-adenosylmethionine decarboxylase of A. culbertsoni indicating this enzyme to be the target for its antiamebic action. This enzyme was, however, not inhibited by sinefungin, suggesting an alternative target for growth inhibition by this compound.

Acanthamoeba↗
PubMed1987

Subpopulations of CD4+ (T4+) cells in homosexual/bisexual men with persistent generalized lymphadenopathy.

Using monoclonal antibodies (anti-2H4 and anti-4B4), CD4+ (T4+) T cells are further subdivided into two major subpopulations of inducers of help (T4+4B4+) and inducers of suppression (T4+2H4+). To determine whether human immunodeficiency virus (HIV) infection results in the depletion of a subset of CD4+ cells, peripheral blood mononuclear cells from patients with persistent generalized lymphadenopathy (PGL) were quantified for the subpopulation of CD4+ T cells, using anti-2H4 and anti-4B4 monoclonal antibodies and fluorescence-activated cell sorter analyser. The proportions and numbers of both T4+2H4+ and T4+4B4+ cells were significantly decreased in PGL as compared to healthy controls. This study demonstrates that HIV infection results in the depletion of both subsets of T4 cells to an almost similar extent.

AIDS-Related Complex↗
PubMed1987

Interleukin 1 and interleukin 2 production in the acquired immune deficiency syndrome (AIDS) and AIDS-related complex.

Interleukin 1 (IL-1) production by freshly isolated and lipopolysaccharide (LPS)-stimulated adherent monocytes-macrophages and IL-2 production by unstimulated and phytohemagglutinin (PHA)-activated T cells were examined in patients with acquired immune deficiency syndrome (AIDS) and AIDS-related complex (ARC). Spontaneous IL-1 production was significantly increased in patients with ARC, whereas IL-1 production by LPS-activated monocytes-macrophages was significantly decreased in patients with AIDS. Spontaneous IL-2 production by unstimulated T cells was significantly decreased in AIDS and IL-2 produced by PHA-activated T cells was significantly decreased in AIDS and ARC. This study shows abnormality of both monocyte and T-cell functions in AIDS and ARC. These abnormalities appear to play a role in the immunopathogenesis of AIDS.

AIDS-Related Complex↗
PubMed1987

1,25-Dihydroxyvitamin D3-mediated inhibition of human B cell differentiation.

We have examined the mechanisms of 1,25-dihydroxyvitamin D3 (D3)-mediated inhibition of human B cell differentiation to immunoglobulin (Ig) secreting cells. B lymphocytes were purified from human tonsils and peripheral blood mononuclear cells. Mononuclear cells were separated into adherent cells and nonadherent cells. Cells were stimulated with Staphylococcus aureus Cowen I (SAC) or pokeweed mitogen (PWM) for 7 days and immunoglobulin production was measured by ELISA assay, 1,25-dihydroxyvitamin D3 was added at different times during cultures. 1,25-Dihydroxyvitamin D3, in a dose-dependent manner, inhibited both SAC and PWM-induced Ig production by mononuclear cells. The maximum inhibition was observed when 1,25-dihydroxyvitamin D3 was added at the beginning of culture, but inhibition could still be observed when 1,25-dihydroxyvitamin D3 was added on day 4 of cultures. The inhibitory effect of 1,25-dihydroxyvitamin D3 on Ig production was significantly greater on mononuclear cells than on nonadherent cells. Addition of in vitro purified IL-1 to nonadherent cells enhanced 1,25-dihydroxyvitamin D3-induced inhibition of Ig production. 1,25-Dihydroxyvitamin D3 also inhibited the expression of IL-2 receptors on B cells activated with SAC. 1,25-dihydroxyvitamin D3 did not inhibit Ig production by SAC preactivated B cell blasts in response to T cell supernatants. These data suggest that vitamin D3 inhibits Ig production by inhibiting IL-2 receptor expression on B cells and via its effect on adherent macrophages. Vitamin D3 does not influence the effect of differentiation factors on activated B cells that have already expressed growth/differentiation factor receptors.

Adult↗