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Biomedical subjects

V Kumar

Publications and source records attributed to V Kumar.

At least 739 records · Page 41Linked to original sources
PubMed1984

A standardized method of detecting antibodies to extractable nuclear antigens (RNP and Sm) by gel precipitation.

Because of the importance of the detection of antibodies to RNP and Sm in the diagnosis of mixed connective tissue disease, systemic lupus erythematosus and certain forms of systemic sclerosis, the various factors which influence the sensitivity of the gel precipitation method for the detection of these antibodies were investigated. The agarose concentration, thickness, well sizes and distance between wells influence the sensitivity of the precipitin reactions. Suitable conditions for a sensitive and reproducible test system are specified. Because of variations in the antigenic composition of extractable nuclear antigen preparations made by different methods and from different tissue sources, a two-dimensional "chessboard titration" using serial twofold dilutions of a reference serum to test doubling dilutions of antigen preparations is recommended for standardizing different lots of antigen. Using the above-mentioned standardized agarose plates and appropriate reference serum with anti-Sm and/or anti-RNP antibodies in a chessboard titration, it is recommended that acceptable use dilution of antigen preparation be two doubling dilutions before reaching an endpoint. The reference sera selected should be compared to US reference standards supplied by the Center for Disease Control.

Antibodies, Antinuclear↗
PubMed1984

Functional characteristics of lymphocytes isolated from the rat large intestine. Response to T-cell mitogens and natural killer cell activity.

Using successive ethylenediaminetetraacetic acid and collagenase treatments, two fractions of mucosal lymphocytes have been isolated from the rat large intestine that differ in morphologic and functional characteristics. Intraepithelial lymphocytes consisted largely of granular lymphocytes (91 +/- 6%) that did not respond to stimulation with phytohemagglutinin or concanavalin A, but had natural killer cytotoxic activity against the YAC-1 cell line. The natural killer cytotoxicity of the intraepithelial lymphocytes was specifically reduced by the addition of increasing numbers of unlabeled homologous tumor cells but not by unlabeled thymocytes. The sensitivity of different target cell lines to lysis by intraepithelial lymphocytes was the same as splenocytes from the same rat strain. Lymphocytes from the lamina propria contained 21 +/- 4% granular cells with the remainder being typical small lymphocytes. The lamina propria fraction responded well to stimulation with concanavalin A, phytohemagglutinin, and pokeweek mitogen, and also had natural killer activity against YAC-1 cells.

Animals↗
PubMed1984

Intrarenal arterial pattern of human kidney--corrosion cast study.

Study of intrarenal arterial pattern of kidney by corrosion cast method has been carried out on 100 kidneys obtained from post mortem bodies. The abnormal origin of renal artery is rare --only 3 percent. Renal artery divided extrarenally in 71 percent, intrarenally in 16 percent and at the hilum in 11 percent cases into anterior and posterior divisions. Renal artery did not divide into 2 divisions but continued as anterior division and divided into upper, middle and lower segmental arteries in one percent. The branching pattern of anterior division shows 5 different variations. Posterior segmental artery showed 3 different patterns. Variations in the origin of apical segmental artery were divided in 7 types and that of lower segmental artery in 5 types. The variations in origin of upper and middle segmental arteries were also observed. There were variations in the intrarenal branching pattern of all the segmental arteries.

Aorta, Abdominal↗
PubMed1983

Purification and characterization of a cysteine dioxygenase from the yeast phase of Histoplasma capsulatum.

A cysteine dioxygenase, cysteine oxidase (EC 1.13.11.20), has been purified from the cytosolic fraction of yeast phase cells of the dimorphic fungus Histoplasma capsulatum. The cysteine oxidase is an iron-containing dioxygenase with a molecular weight of 10500 (+/- 1500) and is present only in the yeast phase of the fungus. The enzyme is highly specific for L-cysteine, with a Km of 2 X 10(-5) M in vitro. The product of cysteine oxidation is cysteinesulfinic acid, as analyzed by thin-layer chromatography and mass spectroscopy. To our knowledge, this is the first cysteine oxidase isolated from a fungus, and it probably plays an important role in the mycelial to yeast phase transition of H. capsulatum during which redox potential and cysteine levels are crucial factors.

Cysteine Dioxygenase↗
PubMed1983

Effects of exogenous prolactin on ovarian growth and fattening in the redheaded bunting, Emberiza bruniceps.

Subcutaneous daily injections of ovine prolactin (PRL) inhibit photoperiodic induction of gonads and fattening in the female redheaded bunting (Emberiza bruniceps). However, birds respond to the same photoperiod (15L:9D) after withdrawal of the exogenous PRL. Further, PRL injections given in late hours during the subjective days induce ovarian regression in the photostimulated females. The results suggest that the PRL has an inhibitory role on gonadal photoperiodic responses in redheaded buntings, and extend our understanding of the regulatory function of PRL in migratory birds.

Animals↗
PubMed1983

Lack of correlation between mycoplasma induced IFN-gamma production in vitro and natural killer cell activity against FLD-3 cells.

Interferon (IFN) stimulates natural killer (NK) cell-mediated lysis of tumor cells. However, it is not clear whether IFN production is essential for NK cells to lyse their target cells in vitro, especially in long-term (greater than 18 hrs) assays. To investigate this, 0.5 X 10(6) normal mouse spleen cells were cocultured in RPMI 1640 medium with Friend erythroleukemia cells (FLD-3) (1 X 10(4] for 24 hours under conditions which cause lysis of FLD-3 cells. Supernatant fluid from such cultures demonstrated antiviral activity (100-200 units) which could be identified as IFN-gamma. Prior filtration of spleen cells over nylon wool, and pretreatment with anti-Thy-1.2 + C' abrogated their ability to generate IFN-gamma without affecting their NK (FLD-3) activity. The IFN-gamma producing cell which could also be detected in spleens of nu/nu BALB/c mice lacked cell surface, Lyt-1, Lyt-2, and NK-1.2 antigens. The stimulus for IFN-gamma induction appeared to be Mycoplasma arginini carried in the FLD-3 tumor cells. Although mycoplasma-free FLD-3 cells failed to induce IFN in vitro, they retained their susceptibility to NK cell-mediated lysis. We conclude that IFN induction is not essential for NK(FLD-3) cell-mediated lysis; indeed IFN detected in NK cell assays may be produced in response to mycoplasma infection of the tumor cells. The Thy-1.2 positive cells stimulated by mycoplasma to produce IFN-gamma lack several characteristics of T-cells or NK cells.

Animals↗
PubMed1983

Critical level of oxygen delivery in anesthetized man.

Fifty-eight patients studied were anesthetized with diazepam, pancuronium, and a moderate dose of fentanyl; 99 sets of multiple hemodynamic variables were measured after sternotomy and before cardiopulmonary bypass. The relationship between oxygen consumption (VO2) and oxygen delivery (DO2) was studied. The critical value of DO2 was identified to be 330 ml/min X M2 or 8.2 ml/min X kg by an analysis of the regression lines. When DO2 was less than 330 ml/min X M2, the value of VO2 decreased in proportion to a decrease in DO2 and VO2 was expressed as: VO2 = 0.36 X DO2 - 11.20 (n = 30, r = 0.77, p less than 10(-6). At DO2 greater than 330 ml/min X M2, VO2 values plateaued at 109 +/- 16 (SD): n = 69; r = -0.02, p greater than 0.05; while mixed venous oxygen tension (PVO2) decreased in proportion to the decrease in DO2, suggesting compensatory increase of oxygen extraction. A decrease of VO2 at DO2 less than 330 ml/min X M2 suggests tissue oxygen deprivation occurred.

Adult↗
PubMed1983

Does obesity affect recovery? A study using intravenous methohexitone and Althesin for short procedures.

One hundred and twenty unpremedicated patients, scheduled for minor gynaecological procedures, were randomly allocated to receive Althesin or methohexitone to supplement N2O and O2 anaesthesia. Patients were assessed as thin, medium or fat according to the degree of obesity as measured by skinfold calipers. The range of mean times for the patients to open their eyes was 3.1-4.0 minutes, to be orientated was 4.4-6.7 minutes and to perform a manipulative test was 27.7-32.1 minutes. No statistically significant differences were seen in these indices of recovery whether they received Althesin or methohexitone or whether they were thin, medium or fat. A paper and pencil test was also performed. Induction doses of the intravenous agent were calculated on a body weight basis and increments given only in response to movement. The mean total dose of Althesin was decreased from 1.33 mg total steroid/kg for thin patients to 1.06 mg total steroid/kg for fat patients (p less than 0.01). The mean total dose of methohexitone was decreased from 3.4 mg/kg for thin patients to 2.9 mg/kg for fat patients which was not significant.

Adolescent↗
PubMed1983

The effect of age on recovery. A comparison of the kinetics of thiopentone and Althesin.

Eighty unpremedicated patients undergoing dilatation and curettage were randomly allocated to receive induction of anaesthesia with either Althesin or thiopentone prior to maintenance with nitrous oxide, oxygen and halothane. Patients in each group were divided into those under 50 years ('young') or over 50 years ('old'). Recovery was assessed by the time taken to opening their eyes, to give correct date of birth and to achieve their baseline ability of manipulative skill with a children's post box toy. There was no difference in the time taken to open eyes or give correct birth date whether the patients received Althesin or thiopentone, or whether they were 'young' or 'old'. An age-related difference emerged with the post box test in patients who had received thiopentone, the older patients recovery time being increased from 28.5 minutes to 45.1 minutes. There was no difference between the old and young patients who received Althesin in the time taken to complete the post box test.

Adolescent↗