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Biomedical subjects

S Kumar

Publications and source records attributed to S Kumar.

At least 541 records · Page 30Linked to original sources
PubMed2001

Antimutagenic potential of extracts isolated from Terminalia arjuna.

Terminalia arjuna is an important medicinal plants widely used in the preparation of Ayurvedic formulations used against several ailments. The present investigation was aimed at the fractionation of crude extracts from the bark of T. arjuna in order to isolate and purify the antimutagenic factors present. The antimutagenicity assay was performed to check the modulatory effect of these fractions against NPD, sodium azide, and 2AF, using the Ames Salmonella his+ reversion assay. Most of the phenolic fractions exhibited mutagen specificity against direct-acting mutagens, being effective in suppressing the frameshift mutagen NPD but failing to inhibit sodium azide (base pair substitution)-induced his+ revertants. ET-1 fraction triterpenoid diglycoside showed a marked effect against sodium azide but was ineffective against NPD. In the case of the indirect-acting mutagen 2AF, all the fractions were found to be quite potent in modulating its mutagenicity in both TA98 and TA100 tester strains of Salmonella typhimurium. The results indicate that the bark of T. arjuna harbors constituents with promising antimutagenic/anticarcinogenic potential that should be investigated further.

Antimutagenic Agents↗
PubMed2001

Dose-dependent pharmacokinetics and metabolism of valproic acid in newborn lambs and adult sheep.

Dose-dependent pharmacokinetics and metabolism of valproic acid (VPA) were studied in newborn and adult sheep to assess age-related differences in plasma protein binding and metabolic elimination. Newborn lambs received either a 10- (n = 8), 50- (n = 5), 100- (n = 4), or 250-mg/kg (n = 4) VPA i.v. bolus. Individual adult sheep (n = 5) received all four doses in a random order with an appropriate washout period between experiments. Unbound or metabolic clearance of VPA was significantly higher in adult sheep at the two lower doses when compared with lambs, and similar to the lambs at the two higher doses. Plasma protein binding was nonlinear at all doses. Estimates of binding capacity (B(max1)) at the saturable site were higher in adults (91.8 microg/ml) when compared with lambs (44.9 microg/ml), whereas the opposite trend was observed for binding affinity [K(d1) = 9.6 microg/ml (adult) versus 3.2 microg/ml (lambs)]. Characterization of developmental differences in overall VPA metabolic elimination involved fitting of unbound VPA plasma concentration data to a two-compartment model with Michaelis-Menten elimination. This resulted in similar in vivo estimates of apparent V(max) [445.0 microg/min/kg (adult) versus 429.9 microg/min/kg (lambs)]. However, apparent K(m) estimates appeared to be higher in lambs [30.0 microg/ml (adult) versus 69.6 microg/ml (lambs)]. Similar findings were obtained from in vivo estimates of V(max) and K(m) for VPA glucuronidation obtained from VPA-glucuronide metabolite urinary excretion data. Thus, it appears that age-related differences in metabolic clearance may be related to differences in the apparent in vivo K(m) as opposed to V(max) of VPA glucuronidation.

Aging↗
PubMed2001

Hematological observations as diagnostic markers in dengue hemorrhagic fever--a reappraisal.

OBJECTIVE: To determine the utility of certain clinical and hematological parameters as diagnostic markers of dengue hemorrhagic fever (DHF), namely, (i) tourniquet test, (ii) association of bleeding manifestations with the platelet count, and (iii) "cut off" value of hematocrit diagnostic of DHF in Indian population. DESIGN: Prospective study. SETTING: Tertiary care hospital. SUBJECT: 304 children of DHF presenting between September 1996 to December 1996. RESULTS: The tourniquet test had a low sensitivity and was positive only in 61/239 (25.5%) cases. There was no statistical difference in the incidence of bleeding manifestations between thrombocytopenic and non-thrombocytopenic individuals highlighting poor association of thrombocytopenia with bleeding manifestations. A "cut off" hematocrit value of 36.3% diagnostic of DHF was estimated by discriminant analysis in Indian population. CONCLUSION: The study highlights tourniquet test as a less sensitive diagnostic marker of DHF, poor association of thrombocytopenia with bleeding manifestations and also defines the hematocrit value diagnostic of DHF in Indian population.

Child↗
PubMed2001

An oligo astrocytoma with widespread calcification along axonal fibres.

A rare case of a young man with a diffusely calcified oligo astrocytoma in right parieto occipital region, which spread along the axonal fibres into right temporal lobe and to the left parietal lobe is presented. Computed tomography (CT) and magnetic resonance imaging (MRI) demonstrated the extent of the lesion. The mass was partially resected.

Adult↗
PubMed2001

Reproductive health needs and care seeking behaviour of pavement dwellers of Calcutta.

An unabated growth of street dwellers in the city of Calcutta is reported to be due to twin reasons like, migration of rural poor people as well as uncontrolled fertility among these poor settlers of the city. A community-based study on reproductive health, fertility and related care seeking behaviour was studied among a sample of women of child bearing age living on streets of Calcutta. Besides, the quite common conditions like leucorrhoea (28.5%), menstrual irregularities (12.3%), infertility (2.5%) and STDs (1.3%) were also reported. But most of these illnesses (three-fourth) were uncared for, and the remaining one-fourth sought treatment from govemment institutions, private agencies or even from untrained practitioners (quacks). The reproductive behaviour of street dwelling women was characterised by early marriage, teenage pregnancies, and scarce use of contraceptives (32%) as well as frequent abortions (2.8%). Very few pregnant women received adequate antenatal care (3.8%). Coverage of tetanus toxoid immunisation (68.5%) and proper iron and folic acid supplementation (16.7%) were also poor. Whereas, antenatal care was received mostly from government health institutions (71%), home delivery (ie, on street) was a common practice and conducted mostly by untrained birth attendants (51.8%).

Adolescent↗
PubMed2001

Disappearing cystic cerebellar medulloblastoma: the ghost tumour.

A case of medulloblastoma, which disappeared following steroid administration and a single sitting of radiotherapy (8Gy) is presented. At surgical exploration tumour was not found, multiple biopsies were negative. Post operative CT scan too did not show the tumour. Five months later, tumour reappeared in left cerebellar lobe in cystic and solid form. Patient was reoperated and tumour was decompressed. The biopsy showed medulloblastoma. To our knowledge, medulloblastomas are not known to be completely responsive to either of these modalities.

Adolescent↗
PubMed2001

Three-dimensional structure of a new form of mare lactoferrin in 70% PEG 400 at 3.8 A resolution.

Three-dimensional (3D) structure of a new form of diferric mare lactoferrin has been determined at 3.8 A resolution. The protein was crystallized in a space group P2(1)2(1)2(1) with a = 80.1 A, b = 103.7 A, c = 112.2 A with a solvent content of 57%. The structure was solved by molecular replacement method using the model of native mare lactoferrin. The structure has been refined using X-PLOR to a final R-factor of 22.6% for all the data in 15.0-3.8 A resolution range. The final refined model comprises 5281 protein atoms, 2Fe3+ and 2CO3(2-) ions. The protein folds into two globular N- and C-lobes. The two lobes are further divided into two domains N1, N2 in the N-lobe and C1, C2 in the C-lobe. The overall folding of the protein is similar to that observed for the native protein. The superposition of Calpha traces of native mare lactoferrin and the present structure gives an r.m.s shift of 0.7 A. There is a slight variation in the orientation of two lobes but the domain orientations in the present structure are identical to those observed in the native mare lactoferrin.

Animals↗
PubMed2001

Characterization of toxin from cheilanthes fern and its effect on lymphocyte proliferation and DNA fragmentation.

Thin layer chromatography of aqueous extract of whole Cheilanthesfarinosa fern indicated the presence of ptaquiloside or ptaquiloside like compound, coinciding Rf values with that of Pterosin B standard. HPLC analysis revealed the presence of 26.3 mg/kg ptaquiloside. In vitro studies of the aqueous extract on lymphocyte culture revealed a correlation between stimulative indices and concentration of aqueous extract. Stimulation in lymphocyte proliferation was in order of bracken > cheilanthes > ConA> ptaquiloside standard. On incubation of lymphocyte with aqueous extract of ferns, no DNA damage was observed in isolated DNA.

Animals↗
PubMed2001

The TGF beta receptor endoglin in systemic sclerosis.

Immunohistochemical, flow cytometric and ELISA studies were performed to examine the expression of endoglin (CD105, a TGF beta receptor) on dermal endothelial cells, peripheral blood monocytes and free and bound serum levels in patients with systemic sclerosis as compared with appropriate controls. Endoglin was found to be significantly upregulated on dermal blood vessels in patients with scleroderma (and in patients with inflammatory skin disorders) as compared to healthy skin (p < 0.05). In contrast, there was no significant difference in endoglin expression on circulating blood monocytes between scleroderma patients and patients with a rheumatic disoder or healthy control subjects; however, endoglin expression was upregulated on monocytes in inflammatory joint fluid from patients with rheumatoid arthritis. Endoglin expression on monocytes was also influenced by isolation techniques and during whole blood culture. No differences were found in circulating free or bound endoglin levels between scleroderma patients and healthy controls. In conclusion, endoglin expression on dermal endothelial cells was significantly enhanced in scleroderma but levels on circulating monocytes and in the serum were within normal limits. The functional significance of this upregulation is uncertain but may reflect endothelial activation in scleroderma.

Aged↗
PubMed2001

Formation of surfactant-like-particle in rat intestine following chronic ethanol feeding.

Ethanol feeding to rats daily for 40 days induces the secretion of surfactant-like-particles in intestine. The isolated lipoprotein particles were enriched with alkaline phosphatase activity and had high phosphatidylcholine content. There was no difference in disaccharidases activities associated with the particles from control and ethanol fed rats. These results suggest that ethanol induced surfactant-like-particles in rat intestine.

Animals↗
PubMed2001

Effect of DDVP on the histology and AChE kinetics of heart muscles of Rattus norvegicus.

The LD50 of DDVP (Dichloro, dimethyl vinyl phosphate) for Rattus norvegicus was 21.4 mg/kg. b.w. The two sub lethal doses 1 and 3 mg/kg showed many histopathological changes in the working heart muscles and also showed significant necrosis in this S-A node, A-V node and bunble of His of the cardiac conducting system. These sublethal doses of the OP pesticide caused a significant inhibition of AChE. The maximum inhibition was noticed at the highest dose. The enhanced inhibitory constant Km and ACh contents in the heart muscles with the increase of dose showed inhibition of enzyme. The constant Vmax showed competitive nature of inhibition. A significant inhibition of AChE (69%) indicated that DDVP is a strong inhibitor of enzyme in heart.

Acetylcholinesterase↗
PubMed2001

Lead induced spermatoxicity in mouse and MPG treatment.

Protective efficacy of MPG (2-mercaptopropionyl glycine) was studied against the toxic effects of lead acetate in Swiss albino mice. The animals were treated with single dose of lead acetate @ 180, 200 and 250 mg/kg b.wt. in presence and absence of MPG. The results indicated that the body weight was slightly higher in MPG treated groups on day 10 as compared to only respective lead treated groups in all the three dose level. However, significantly lower body weight was observed in both lead treated and lead along with MPG treated groups as compared to control. Patten of mortality is similar in both lead treated and lead plus MPG treated groups. Conspicuous degenerative changes in testicular tissues and elevation in sperm head shape abnormality were observed in both lead treated and lead along with MPG treated groups but the sperm head shape abnormality and damage were more in lead treated groups as compared to lead plus MPG treated groups. But this difference was non-significant between the two groups. These observations suggest that MPG may not be significantly effective against lead induced damage in testicular tissues at cellular level. However, MPG is able to maintain slightly lower level of sperm abnormality in all the three dose level as compared to their respective lead treated groups. Further, studies are needed to find out the optimum dose of MPG for protection against the lower doses of lead induced lethality as MPG is not significantly effective against the higher doses of lead.

Animals↗
PubMed2001

Sero-reactivity of two different antigenic protein fractions of M.tb H37Ra excretory-secretory antigen in pulmonary and extra-pulmonary tuberculosis.

Excretory-secretory proteins of Mycobacterium tuberculosis H37Ra, have been of diagnostic interest in pulmonary (PTB) and extrapulmonary tuberculosis (EPTB). Two different excretory-secretory antigenic proteins of M.tbH37Ra viz., EST-DE1 (a 6% TCA soluble and DEAE anion exchange purified antigen) and ESAS-7 (50% ammonium sulphate solubilized and SDS-PAGE fractionated antigen) were studied in stick-indirect penicillinase ELISA for detecting tuberculous IgG antibodies in serum samples of pulmonary as well as extrapulmonary tuberculosis (tuberculous lymphadenopathy (TBLN), tuberculous meningitis (TBM), bone & joint tuberculosis (B&J TB), abdominal tuberculosis (Abd. TB) patients. The ESAS-7 antigen has shown comparatively better seroreactivity (90%) than that of EST-DE1 antigen in pulmonary tuberculosis cases. The overall specificity of 93.2% using ESAS-7 antigen was also found better compared to 86.4% obtained using EST-DE1 antigen. Further, in extra pulmonary tuberculosis group, using ESAS-7 antigen 84% (21/25) of histopathologically confirmed TBLN cases and 90% (9/10) clinically diagnosed and ATT responded TBM cases showed positive reaction for tuberculous IgG antibody. The per cent positivity using EST-DE1 antigen was however comparatively low in TBLN and TBM cases, (76% and 80% respectively). In histopathologically proven bone and joint tuberculosis and abdominal tuberculosis cases EST-DE1 antigen showed better sensitivity of 75% and 83.3% respectively in IgG antibody detection compared to that of ESAS-7 antigen (50% and 66% respectively). From the present study, it can be envisaged that ESAS-7 antigenic fraction has a good potential in the diagnosis of pulmonary and certain extra-pulmonary tuberculosis infection (TBLN & TBM) whereas EST-DE1 was found to be better in detecting specific antibodies in bone & joint and abdominal tuberculosis.

Antibody Formation↗
PubMed2001

Candidemia in neonatal intensive care unit.

The present study was conducted over a period of 6 months to determine the Candida species causing candidemia in a neonatal intensive care unit and to analyse the risk factors associated with acquisition of significant fungemia. Speciation of the 19 isolated Candida spp was done by the standard techniques. Antimicrobial susceptibility of these isolates was determined by disc diffusion method against Amphotericin B, Fluconazole, Ketoconozole and 5-Flucytosine. Candida glabrata was the most common species involved (42.1%). Other species isolated were C. tropicalis (31.6%). Calbicans (21.1%) and C.parapsilosis (5.2%). All the isolates were sensitive to Amphotericin B. Resistance to other antigungal agents was seen only in C. globrata. Significant candidemia was seen in 14/19 (72.6%) of neonates. Risk factors found to be associated with significant candidemis in these neonates included intake of multiple broad-spectrum antibiotics (p<0.0001), use of total parenteral nutrition (p<0.045) and ventilators (p<0.0001).

Amphotericin B↗