Biomedical subjects
Publications and source records attributed to S Kumar.
We report a 25-year-old woman who presented with abdominal pain, vomiting and fever, and had an epigastric lump on examination. At laparotomy she was diagnosed to have acute segmental jejunitis. Three days postoperative, she vomited a 2-meter-long tapeworm (Taenia saginata), a rare route of expulsion.
The medical attrition rates of 4 cohorts of recruits undergoing basic military training (BMT) were studied. They were grouped as follows: Group A (n = 3475), a mixture of fit and unfit recruits; Group B (n = 2081), consisting only of fit recruits; Group C (n = 940) comprising only unfit recruits who underwent a 4 to 6 weeks conditioning programme prior to being subjected to a similar 3-month BMT for all 3 groups and Group D (n = 2613) comprising unfit recruits who underwent an extended 4-month BMT. It was found that Group B [Relative risk (RR) = 0.26 95% confidence interval (CI) = 0.21, 0.33] and Group C (RR = 0.45 95% CI = 0.38, 0.62) had significantly lower medical attrition rates compared with Group A (RR = 1). Group D, however, did not show significantly lower attrition rates in spite of a more gradual training pace. When the unfit cohorts were compared, Group C (RR = 0.52 95% CI = 0.40, 0.67) had significantly lower attrition rates than Group D (RR = 1). The major cause of medical attrition in all groups was musculo-skeletal injuries sustained during training. Our results showed that a formal pre-training conditioning programme resulted in lower attrition during BMT and this reduction was more effective than training the recruits at a slower pace by extending the BMT by one month.
The effects of twice-daily injections of L-arginine or D-arginine (200 mg/kg i.p.) for 4 days on morphine-induced antinociception, brain nitric oxide synthase activity and brain and serum distribution of morphine and brain mu-opioid receptors labeled with [3H][D-Ala2,MePhe4,Gly5-ol]enkephalin were determined in male Swiss-Webster mice. Chronic treatment with L-arginine, but not D-arginine, decreased the antinociceptive response to morphine in mice, increased the activity of nitric oxide synthase in the midbrain and decreased brain levels of morphine, compared with vehicle-injected controls. Significant decreases in morphine levels were observed in midbrain, pons and medulla, hippocampus, striatum and spinal cord of L-arginine-treated mice, in comparison with vehicle-injected mice. However, the levels of morphine in cortex, amygdala and hypothalamus of L-arginine- or D-arginine-treated mice did not differ from those of vehicle-injected controls. Acute treatment with L-arginine (200 mg/kg i.p.) or D-arginine (200 mg/kg i.p.) did not modify either morphine antinociception or morphine distribution in brain regions or the spinal cord. Chronic administration of L-arginine or D-arginine did not alter the Bmax or Kd values of [3H][D-Ala2,MePhe4,Gly5-ol]enkephalin binding to the mouse brain membranes. These results suggest that chronic treatment with L-arginine reduces the antinociceptive effect of morphine by increasing brain nitric oxide synthase activity and by decreasing the concentration of morphine in certain brain regions and spinal cord.
Through subtraction cloning approach, we have identified a set of mouse genes with developmentally down-regulated expression in brain. One such gene, termed Nedd2, was found to encode protein similar to the mammalian interleukin-1b-converting enzyme (ICE) and the product of the nematode (C. elegans) cell death gene ced-3. Our data suggest that Nedd2 is an important component of the mammalian programmed cell death machinery.
Previous estimates of maternal and fetal placental and nonplacental clearances in pregnant sheep using a two-compartment open model have revealed higher values of fetal placental clearance (CLfm) compared to the maternal placental clearance (CLmf) for most drugs. This includes the antihistamine diphenhydramine (DPHM), which also has the highest weight-corrected fetal nonplacental clearance (CLfo) among the drugs studied. This study was designed to determine the reasons for this CLfm - CLmf difference and to identify the sites of high CLfo for DPHM. DPHM and a stable isotope-labeled analog, [2H(10)]DPHM, were simultaneously infused to steady state to the mother and fetus, respectively, in five pregnant sheep. CLmf, CLfm, CLmo and CLfo averaged 50.3 +/- 13.2, 214.4 +/- 30.8, 36.6 +/- 1.9 and 109.8 +/- 22.3 ml/min(-1)/kg(-1), respectively. By measuring diphenylmethoxyacetic acid and [2H(10)]diphenylmethoxyacetic acid levels in samples obtained from our previous study of fetal hepatic first-pass DPHM uptake, the hepatic first-pass extraction ratio of the drug from umbilical venous blood was estimated to be 0.44 +/- 0.05. This can account for virtually all of CLfo. Fetal hepatic first-pass uptake of maternally derived DPHM in the paired infusion study reduces the fetal/maternal plasma DPHM concentration ratio and results in significant underestimation of CLmf. When the CLmf estimate is corrected for this factor and for maternal-fetal DPHM plasma protein binding differences, its value approaches CLfm. Fetal hepatic first-pass uptake may also be a factor in the underestimation of CLmf for most of the other drugs. Conversely, a lower value of CLmf compared with CLfm provides evidence for significant fetal hepatic uptake of these compounds.
Explore the source record for details and available documents.
Hexokinase (EC 2.7.1.1) activity in cell-free Plasmodium berghei was 35 and 5 times higher as compared to normal and P. berghei-infected mouse erythrocytes, respectively. Maximal enzyme activity was present in the cytosolic fraction of the isolated parasite. Manifold purification of parasite hexokinase was achieved with Sephadex G-200. Sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE) revealed parasite enzyme subunit in the molecular weight range of 47 kDa with ATP (adenosine triphosphate) Km of 2 mM. Two out of three mice immunised with the hexokinase fraction were protected upon challenge with live parasites.
Explore the source record for details and available documents.
Thioredoxin (Trx) is a small ubiquitous dithiol protein which together with the FAD-containing enzyme thioredoxin reductase (TR) and NADPH (the Trx system) is a hydrogen donor for ribonucleotide reductase essential for DNA synthesis and a general protein disulfide reductase involved in redox regulation. Selenite, selenodiglutathione (GS-Se-SG) and selenocystine are efficiently reduced by thioredoxins and also directly by NADPH and mammalian TR but not by the E. coli enzyme. Incubation of selenite or GS-Se-SG with the Trx system or with mammalian TR results in a rapid formation of selenide, which by redox cycling with oxygen may cause a large non-stoichiometric oxidation of NADPH. Selenocystine is efficiently reduced into two molecules of the selenol amino acid selenocysteine by mammalian TR with a K(m)-value (6 mumol.L-1) and a high turnover number (kappa cat 3200 min-1) almost identical to the natural substrate Trx-S2. TR also directly reduces lipid hydroperoxides and this peroxidase reaction is strongly stimulated by the presence of catalytic amounts of free selenocysteine. Glutaredoxin (Grx) which catalyzes GSH-dependent disulfide reduction also via a redox-active disulfide and Trx are both efficient electron donors to the human plasma glutathione peroxidase providing a mechanism by which human plasma glutathione peroxidase may reduce hydroperoxides in an environment almost free from glutathione. Selenate is reduced by Grx and Trx in the presence of GSH. The DNA-binding of the transcription factor AP-1 is strongly inhibited by GS-Se-SG and selenite. Furthermore, selenide formed by TR-mediated reduction of selenite and GS-Se-SG inhibits lipoxygenase and changes the electron spin resonance spectrum of the active site iron. Mammalian TR with two subunits of 57 kDa has recently been cloned and shown to be homologous to glutathione reductase. The rat enzyme contains a selenocysteine residue in a unique Cterminal position and a conserved SECIS sequence directing insertion of the selenocysteine. The discovery of selenocysteine in mammalian TR may explain the broad substrate specificity of the enzyme and the requirement of selenium for cell proliferation.
We report a patient with multiple glomus tumours and Coats' disease of the retina, an association not previously described. We discuss the possible pathogenesis of these conditions in view of the finding of elevated serum levels of basic fibroblast growth factor.
A total of 257 Proteus strains isolated from urinary tract infection, blood, wound and faeces were studied. Of the strains tested 31 (12 percent) were serum sensitive, 182 (71 percent) were serum resistant and the remaining 44 (17 percent) showed intermediate sensitivity to the pooled normal human serum (PNHS). Strains isolated from adult urines and blood cultures were significantly more sensitive than strains of faecal origin (p < 0.01). No significant difference was seen between strains from faeces and wounds.
Explore the source record for details and available documents.
Antimutagenic potential of a fraction isolated from Terminalia arjuna has been evaluated in TA98 and TA100 strains of Salmonella typhimurium against direct and indirect-acting mutagens. The fraction was quite effective against S9-dependent 2AF while it showed moderate effect against NPD. The fraction was analyzed to be ellagic acid.
BACKGROUND AND OBJECTIVE: To evaluate the safety and efficacy of trabeculectomy with mitomycin-C in the management of postkeratoplasty glaucoma. PATIENTS AND METHODS: Included in this study were 16 eyes of 16 patients who underwent trabeculectomy with mitomycin-C for medically uncontrolled postkeratoplasty glaucoma, each having at least 6 months of follow-up. RESULTS: The mean pretrabeculectomy intraocular pressure (IOP) with maximal medical therapy was 34.6 mm Hg (range 24-45 mm Hg). The mean IOP following trabeculectomy with mitomycin-C was 14.2 mm Hg (range 8-36 mm Hg) by the end of a mean follow-up of 14.2 months (range 8-32 months). Fourteen eyes (87.5%) had complete success, 1 eye (6.25%) had qualified success, and 1 eye (6.25%) had failure. All the patents had the same or better visual acuity, compared with the preoperative value. None of the patients had postoperative complications, such as shallow anterior chamber, epithelial defect, or hypotony. CONCLUSIONS: Trabeculectomy with mitomycin-C is a safe and effective modality in the management of medically uncontrolled postkeratoplasty glaucoma.
The influence of electrode type, interelectrode distance (IED) and electrode orientation on EMG signals from the paraspinal muscles was investigated. Bipolar electrodes were placed at distances 2, 3, 4, 6 and 8 cm over the erector spinae in the cranio-caudal direction ("in series") as well as in the direction perpendicular to it ("in parallel"). Ten subjects performed 5 s isometric contractions of the erector spinae at 20, 40, 60, 80 and 100% MVC by pulling upward on a handlebar attached to the floor. RMS EMG signals were analyzed for mean average amplitude (AA). Mean total power (TP) and mean median frequency (MF) of the raw EMG signal were determined using fast Fourier transform. In addition to graded loading, sustained fatiguing contractions were performed from which TP and MF were obtained. With increasing IED the AA and TP increased while MF decreased. Although a trend towards higher AA, TP and MF was found for electrodes "in series", as compared to those "in parallel", the difference never reached significance. It is concluded that consistent information about muscle activity was obtained with Miniature Biopotential Skin Electrodes and 14445C Hewlett-Packard electrodes independently from IED or orientation. Orientation "in parallel" prevented the electrodes from sliding during muscle contraction. The third tested type, electrodes developed in the Neuromuscular Research Center, Boston, proved extremely sensitive to movement.
Explore the source record for details and available documents.