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Biomedical subjects

M S Kumar

Publications and source records attributed to M S Kumar.

126 records · Page 7Linked to original sources
PubMed1978

Serum hydrocortisone (cortisol) values in normal and adrenopathic dogs as determined by radioimmunoassay.

Using a specific radioimmunoassay, serum hydrocortisone values were measured in dogs. Between 9:00 AM and 10:00 AM, the base-line hydrocortisone value for 56 clinically normal dogs ranged from 6.0 to 28.5 ng/ml, with a mean value of 17.8 +/- 1.32 ng/ml (mean +/- SEM). Marked differences due to age, sex, body weight, or breed were not observed in the hydrocortisone values. In 11 dogs with definitive hyperadrenocorticism, serum hydrocortisone values were from 32 to 148 ng/ml. In 2 dogs with hyperadrenocorticism, the values were 4.5 and 3.1 ng/ml. The estimation of serum hydrocortisone values by radioimmunoassay is simple and precise, and can be utilized to aid in the diagnosis of adrenopathy in dogs.

Adrenocortical Hyperfunction↗
PubMed1978

Observations on the ovaries of zebu cattle in Northern Nigeria.

A morphological study was carried out on ovaries of 236 local zebu cattle. Ovaries from 189 of the cattle were found to be abnormal grossly. Histological observations indicated changes due to old age. The findings are discussed in relation to the occurrence of low reproductive efficiency in cattle in Northern Nigeria.

Age Factors↗
PubMed1977

The relationship of thyroid-stimulating hormone (TSH), thyroxine (T4), and triiodothyronine (T3) in primary thyroid failure.

Thyroid-stimulating hormone (TSH), serum thyroxine (T4) and triiodothyronine (T3) in sera of 100 patients with primary thyroid failure were measured by radioimmunoassay. Effective thyroxine ratio (ETR) was also measured in 69 of these sera. TSH was elevated in all, with a mean of 76.7 +/- 55 micromicron/ml (range 11 to 140 micromicron/ml, and was used to confirm the diagnosis. Mean T4 and T3 levels in the group were 1.8 +/- 1.5 microgram/100 ml (range less than 0.2 to 7.0 microgram/100 u.) and 76.7 +/- 76 ng/100 ml (range less than 10 to 600 ng/100 ml), respectively. Mean ETR was 0.81 +/- 0.05. A moderate inverse relationship was observed between TSH and T4 (r = 0.73), in contrast to TSH and T3 and TSH and ETR, which showed comparatively poor relationships (r = 0.41 and 0.43). This observation, in addition to the finding that 17 patients had subnormal T4 but normal or elevated T3, suggests that normal T3 levels alone may not be sufficient to maintain euthyroidism. In contrast, there were only three clinically hypothyroid patients who had elevated TSH, normal T4, but subnormal T3 levels. This study indicates that T4 and T3 may function together to maintain euthyroidism, and that in addition to serum TSH, T4 determination has more diagnostic value than serum T3 or ETR in these patients.

Adolescent↗
PubMed1977

Possible source and control of trauma-induced glucagonemia in dogs.

Plasma concentrations of glucose, insulin, and glucagon were studied in 10 adult mongrel dogs given (intravenous administration) a large dose of glucose (1g/kg of body weight) both before and after partial (50%) pancreatectomy. A proportional decrease in plasma immunoreactive insulin was observed in partial pancreatectomized dogs. Peak insulin response decreased from presurgery concentrations of 71 +/- 14 muU/ml (mean +/- standard error of the mean) in the dogs before surgical operation (presurgical value) to 52 +/- 6 muU/ml 1 or 4 days after surgical operation. Partial pancreatectomized dogs also showed a reduced plasma glucose removal rate. Fasting plasma concentrations of glucagon, on the other hand, increased by about 80%, from 253 +/- 25 pg/ml to 460 +/- 43 pg/ml 24 hours after operation. Despite an increased glucagon concentration in the dogs after partial pancreatectomy, plasma concentrations of glucagon responded (decreased) to large gulcose dosage administration. Plasma glucagon concentration returned to presurgical value by the 4th postsurgical day.

Animals↗
PubMed1976

Radioimmunoassay for serum cortisol with 125I-labeled ligand: comparison of three methods.

We evaluated a previously modified double-antibody radioimmunoassay for serum cortisol. It was compared with the conventional double-antibody method that includes the usual extraction step, and also with an antibody-coated tube method. In this modified method, cortisol was released from its binding globulin by enzymatic degradation rather than by extraction with ether, and a preincubated mixture of first and second antibody was used to separate antibody-bound cortisol from free. These two steps shortened total asssay time significantly. Results still correlated well (r = 0.87) with results by the conventional melthod, but the antibody-coated tube method gave lower results (r = 0.61). Because of its good correlation with the conventional method, this method was thought to be more accurate. In 52 normal subjects, mean cortisol concentrations at 0800 and 1700 hours were 161 +/- 52 (SD) mug/liter and 91 +/- 27 mug/liter, respectively. In 16 normal subjects, cortisol values before and after dexamethasone treatment (1 mg at midnight) were 134 +/- 53 mug/liter and less than 20 mug/liter. In the same subjects, cortisol concentrations before and 30 min and 60 min after Cortrosyn (synthetic corticotropin1-24, 0.25 mg) administration were 103 +/- 25, 205 +/- 45 and 223 +/- 51 mug/liter, respectively.

Cosyntropin↗
PubMed1975

An improved radioimmunoassay of serum gastrin using commercial kit.

Our experience with a commercially available kit for the measurement of serum gastrin has been reported. Significant non-specific interference was noted by the addition of serum contents in the assay which lead to erroneous results. Use of gastrin free serum as a diluent in the standard curve was found to improve the mean recovery of added gastrin. With this modification the procedure was evaluated for its clinical application. In 30 normal subjects, the fasting mean gastrin level was 78.7 plus or minus 31.9 (S.D.) pg/ml; in 18 of these individuals the postprandial mean level was 118.3 plus or minus 26.7 (S.D.) pg/ml. In 15 patients with pernicious anemia the mean level was 912 plus or minus 779 pg/ml; and in 4 patients with Zollinger-Ellison (ZE) syndrome the mean gastrin level was 1950 plus or minus 379 (S.D.) pg/ml. A significant rise in gastrin level was noted in patients with kidney failure during and after dialysis (p smaller than 0.05).

Anemia, Pernicious↗
PubMedDate not supplied

Spontaneous pneumothorax complicating rheumatoid lung disease.

This case report describes the pleuro-pulmonary involvement in a young patient with rheumatoid arthritis (RA) of one and half year duration. The early involvement of lung interstitium in a 27-year-old male and development of pneumothorax were the unusual features. The various aspects of rheumatoid lung disease (RLD) and its clinical significance were briefly discussed.

Adult↗
PubMedDate not supplied

The role of spatial interactions in creating the dispersion of transmembrane potential by premature electric shocks.

Strong electric shocks applied during the refractory period can initiate or terminate cardiac arrhythmias. To elucidate the underlying mechanism, Knisley et al. used rabbit papillary muscle in vitro to scan the refractory period of an action potential with shocks of different strengths. The resulting map of the shock-induced changes in the transmembrane potential (Vm) illustrates the substrate for the creation of rotors. Our study uses computer simulations to reproduce this experimental map. Three models (a space-clamped membrane, a single cell, and a one-dimensional fiber) were used to determine whether the observed map was caused by (i) the intrinsic dynamics of the membrane, (ii) the simultaneous depolarization and hyperpolarization of the opposite ends of each cell, or (iii) spatial interactions involving the whole muscle strand. The results show that the membrane and single cell models cannot reproduce the experimental map. The fiber model reproduces the shock-induced changes in Vm and demonstrates that they are caused by a propagating disturbance, which, depending on the coupling interval and the shock strength, can be a new action potential or an electrotonus and can arrive from the depolarized end or from both depolarized and hyperpolarized ends of the fiber. These results indicate that the induction of rotors in the heart may not be a direct effect of the electric field.

Action Potentials↗