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Biomedical subjects

R D Gupta

Publications and source records attributed to R D Gupta.

16 recordsLinked to original sources
PubMed1993

The zinc finger gene Krox20 regulates HoxB2 (Hox2.8) during hindbrain segmentation.

The zinc finger gene Krox20 and many Hox homeobox genes are expressed in segment-restricted domains in the hindbrain. The restricted expression patterns appear before morphological segmentation, suggesting that these transcription factors may play an early role in the establishment and identity of rhombomeric segments. In this paper, we show that the HoxB2 (Hox2.8) gene is normally upregulated in rhombomeres (r) 3, 4, and 5, and we identify an enhancer region upstream of the gene that imposes r3/r5 expression in transgenic mice. This enhancer contains three Krox20-binding sites required in vitro for complex formation with Krox20 protein and in vivo for rhombomere-restricted expression. In transgenic mice, Krox20 expressed in ectopic domains can transactivate a reporter construct containing the HoxB2 r3/r5 enhancer. These data demonstrate that Krox20 is a part of the upstream transcriptional cascade that directly regulates HoxB2 expression during hindbrain segmentation.

Animals↗
PubMed1991

Electrocardiographic changes in tetanus: a serial study.

Serial electrocardiograms (ECGs) were recorded in 20 consecutive male patients admitted to the Infectious Diseases Hospital, Calcutta with generalised tetanus. Age of patients varied from 5 to 40 years (mean age 20.4 years). Ten patients died. ECGs were recorded daily for the first week after admission and later every 2nd or 3rd day. Altogether, 167 ECGs were analysed. Sinus tachycardia was present in 17 (85%) patients, prolonged QT interval in 12 (60%) patients, non-specific ST-T abnormalities in 12 (60%) patients and P wave changes in 10 (50%) patients. Other abnormalities recorded, included short PR interval, supraventricular tachycardia, intraventricular conduction delay, sinus bradycardia, 1 degree A-V block, abnormal axis deviation, right ventricular hypertrophy and sino-atrial Wenckebach phenomenon, although all of the findings cannot clearly be attributed to tetanus. Spatial QRS-T angle was calculated in 18 of these patients to determine any possible change in this parameter of prognostic significance. Two out of 9 who survived had abnormally wide (greater than or equal to 55 degrees) spatial QRS-T angle on admission; the angle narrowed with recovery. In the non-survivor group, 4 patients had abnormally wide QRS-T angles on admission; further widening was noted in patients on whom follow-up tracings were available. The difference in spatial QRS-T angle between the survivor and the non-survivor groups was statistically significant (p less than 0.05). Spatial QRS-T angle changes have not been reported in tetanus before. Although non-specific, serial study in individual cases would be useful in assessing prognosis.

Adolescent↗
PubMed1987

Influence of the dwarfing gene dw on egg production and viability under summer heat stress.

1. Dwarf egg layer (Narmada XL) dwarf broiler (DB) and normal bodied sib (NB) hens were studied under cyclic summer hot and dry heat stress of 21.1 to 45.5 degrees C for a period of 50 d. The genotype effect for egg production was significant (P less than 0.01). 2. N-XL and DB genotypes laid 12.1% more eggs than NB. Egg production declined by 3.17, 1.27 and 3.25% for a rise in temperature (maximum) of 1 degree C for N-XL, DB and NB genotypes respectively. 3. Egg production in Narmada XL declined by 42% compared to 25% in the dwarf broilers. The regression coefficients differed significantly. 4. For polygenically identical DB and NB broiler breeder hens the heat stressor significantly reduced egg production 1.98% more in the NB genotype compared with DB with a 1 degree C rise in temperature. 5. Mortality was less in the N-XL as compared to DB, but NB hens showed 11.7% more mortality than dwarfs.

Animals↗
PubMed1980

Effect of dietary protein composition on placental protein, nucleic acid, free alpha amino N and enzymes in rats.

Pregnant rats were fed six different diets from the first to the 15th, 17th or 19th day of pregnancy. Diets 1 to 5 contained the same amount of nitrogen (10% casein and unsupplemented or supplemented wheat or Bengalgram diets). Diet 6 contained 20% casein. Total placental protein, RNA, free alpha amino N contents and the activities of the enzymes arginase (EC 3.5.3.1), tyrosine amino transferase (TAT, EC 2.6.1.5) and lactate dehydrogenase (LDH, EC 1.1.1.27) were estimated. The fetal weight and placental weight, total placental protein, RNA and free alpha amino N and the activities of the enzymes increased with the gestational age, but the DNA content became constant after day 17 of gestation. The placental weight, protein, free alpha amino N and RNA contents were significantly reduced on wheat and Bengalgram diets as compared to 10% casein (control) diet. The low activities of arginase, TAT and LDH on these diets indicated impaired protein synthesis, as a result of reduction in the amino acid pool size. The fortification of wheat with lysine and Bengalgram with cystine, methionine and tryptophan showed significant improvement in the fetal weight and placental parameters. The values on the 20% casein diet were significantly higher than those observed on the 10% casein diet.

Amines↗
PubMed1977

Familial occurrence of sinus bradycardia, short PR interval, intraventricular conduction defects, recurrent supraventricular tachycardia, and cardiomegaly.

Four members of a family presenting with sinus bradycardia, a short P-R interval, intraventricular conduction defects, recurrent supraventricular tachycardia (SVT), syncope, and cardiomegaly had His bundle studies and were found to have markedly shortened A-H intervals (30 to 55 msec.) with normal H-V times (35 to 50 msec.). Right atrial pacing at rates as high as 170 to 215 per minute failed to increase the A-H or H-V intervals significantly. The data are compatible with the presence of an A-V nodal bypass tract (James bundle) or even complete absence of an A-V node. Ventricular pacing and spontaneous ventricular premature beats resulted in a short ventriculoatrial conduction time (110 msec.) suggesting that if A-V nodal bypass tracts exist, they are utilized in an antegrade and retrograde fashion. None of the features of WPW syndrome was present. The mechanism of syncope in the mother and daughter was intermittent third-degree heart block. Both went on to develop permanent complete heart block despite electrophysiologic studies demonstrating 1:1 A-V conduction at extremely rapid atrial pacing rates and both required implantation of permanent pacemakers. The mechanism of syncope in the two brothers was possibly marked sinus bradycardia, but transient complete heart block has not been ruled out. Permanent pacemaker therapy was recommended for both. The nature of the cardiomegaly, which was mild in three patients, is not known. Although not well documented, several maternal relatives have had enlarged hearts, SVT, complete heart block, and syncope.

Adolescent↗
PubMed1976

Tissue digoxin concentrations at digoxin intoxication in normal, acutely hypokalemic, and acutely hyperglycemic dogs.

Thirty intact dogs were studied to determine digoxin concentration in various tissues after ventricular tachycardia had been induced by digoxin infusion. A control group was infused solely with digoxin. A second group was made acutely hypokalemic by glucose-insulin infusion before the digoxin infusion. A third group was infused with glucose and digoxin to determine the effect of increased blood glucose levels and osmalarity on the induction of ventricular tachycardia. Results were: (1) The amount of digoxin infused to produce ventricular tachycardia did not differ getween the normal and hypokalemic groups. (2) The concentration of digoxin in various parts of the heart, other muscle tissue, renal cortex, and liver did not differ between the normal and acutely hypokalemic dogs although the amount excreted in bile and urine was reduced in hypokalemia. (3) Acute hypokalemia did not sensitize the myocardium to the arrhythmogenic effects of digoxin. (4) Ventricular tachcardia occurred at a similar plasma digoxin level in normal and acutely hypokalemic dogs. (5) In dogs with a lowered plasma potassium level, junctional tachycardia occurred whereas it did not occur in normal dogs or those with only a high blood glucose level. (6) Ventricular tachycardia occurred in the hyperglycemic dogs at a plasma digoxin level of 170 ng/ml, which was significantly greater than in the other experiments (7) Acute hyperglycemia reduced the mean rate of myocaridal uptake of digoxin into atria and right and left ventricular tissue; and the concentration of digoxin in atria, left ventricle, and interventricular septum was lower at the time of ventricular tachycardia than occurred in normal dogs. (8) Lowering the plasma potassium level in the presence of acute hyperglycemia, which occurred with the glucose-insulin infusion, did increase the myocardial uptake of digoxin. Similar effects of hyperglycemia were noted on mean hepatic uptake and excretion of digoxin and also the renal uptake of the glycoside.

Animals↗
PubMed1975

Echocardiography.

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Echocardiography↗
PubMed1974

Animal bite.

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Adolescent↗