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Biomedical subjects

N Mishra

Publications and source records attributed to N Mishra.

53 records · Page 3Linked to original sources
PubMed1985

Alpha-adrenoceptor changes after oestrogen treatment in platelets and other tissues in female rabbits.

alpha 2-Adrenoceptors on blood platelets have been widely used as a model for alpha-adrenoceptors in less accessible tissues. The effect of oestrogen (200 micrograms/day intramuscularly) on alpha 2-adrenoceptor number and function was studied in immature female rabbits. alpha 2-adrenoceptor number was measured in whole platelets, and membrane preparations of forebrain, hindbrain, spleen and kidney by radioligand binding. alpha 2-Adrenoceptor function was examined by measuring platelet aggregation in vitro and circulatory responses to selective alpha 2-adrenoceptor agonists in vivo. Oestrogen treatment resulted in a significant decrease in platelet alpha 2-adrenoceptor number and function. However, no changes were observed either in receptor number in other tissues or in responses to alpha 2-agonists in vivo. The results suggest that oestrogen modulation of rabbit platelet alpha 2-adrenoreceptor number and function may be different from that of brain, kidney and spleen. Caution should be exercised in extrapolating results from platelets to alpha-adrenoceptors at other sites.

Animals↗
PubMed1983

Effects of morphine and pethidine on coronary vascular resistance, blood pressure, and myocardial infarction-induced cardiac arrhythmias.

In the present study, the effects of morphine and pethidine on coronary vessel resistance (CPP), blood pressure (BP), and experimental myocardial infarction-induced cardiac arrhythmia were investigated. Both morphine and pethidine induced a fall in CPP and BP and inhibited the cardiac arrhythmia. The morphine effects on CPP and BP were largely blocked by mepyramine. The effects of pethidine, on the other hand, were not blocked by mepyramine, propranolol, or atropine. An interesting dose dependent inhibition of cardiac arrhythmia was observed with pethidine.

Animals↗
PubMed1980

Influence of EDTA and its metal complexes on lactic acid fermentation.

A comparative study of the influence of EDTA and its metal complexes with Fe, Co, and Ce on lactic acid fermentation by Lactobacillus delbrueckii was done. It was observed that EDTA alone and its complex with Ce could increase the yield of lactic acid up to 1--2%, while complexes of EDTA with Fe and Co enhanced the yield up to 4--5%.

Cesium↗
PubMed1980

Lactic acid production from molasses by Lactobacillus bulgaricus AU in presence of U, Th, Zr, and Tl.

The influence of uranium, thorium, zirconium, and thallium (I) on fermentation production of lactic acid from molasses by Lacstobacillus bulgaricus AU was studied. It was found that thorium, at lower experimental concentration, and zirconium, at higher experimental concentration, stimulate the acid-producing activity of the bacteria, while uranium and thallium reduce. it.

Culture Media↗
PubMed1980

Fermentative production of lactic acid in presence of some trace elements.

An attempt was made to study the activity of Lactobacillus delbrueckii under the influence of certain trace elements, viz. Tl, U, Th, and Zr. From the results, it was inferred that Tl has comparatively more stimulating effect on the acid-producing activity of the bacteria than U, Th, and Zr.

Lactates↗
PubMed1979

Lactic acid production from molasses by mixed population of lactobacilli.

The production of lactic acid from molasses by mixed populations of (1) Lactobacillus bulgaricus AU (isolated from curd) and L. casei (supplied by NCL, Poona-8, India) and (2) L. bulgaricus, L. delbrueckii (supplied by NCL, Poona-8, India), and L. casei was studied. It has been found that association of L. bulgaricus with L. casei slightly enhances the yield of lactic acid, while the mixed population of L. bulgaricus, L. delbrueckii, and L. casei is as effective as L. bulgaricus alone.

Culture Media↗
PubMed1977

Partial inhibition of postreplication repair and enhanced frequency of chemical transformation in rat cells infected with leukemia virus.

Postreplication repair of DNA and chemical transformation with the carcinogen 4-nitroquinoline-1-oxide were studied in rat cell lines either uninfected or infected with Rauscher leukemia virus. The results indicate that equivalent amounts of carcinogen are bound to the DNA initially and removed during excision repair. However, the lines differ in that the infected line alone exhibits both sensitivity to nitroquinoline-oxide-induced transformation and a partial inhibition of the postreplication repair process after notroquinoline oxide or UV treatment.

4-Nitroquinoline-1-oxide↗
PubMed1975

Molecular mechanism of in vitro transformation of mammalian cells by chemical carcinogens.

BHK21 clone 13 cells transformed by dimethylnitrosamine (DMN) or nitrosomethylurea (NMU) ("alkylating" chemical carcinogens) appear to be restricted by temperature in the expression of their transformed phenotype. When grown at 38.5 degrees C, they exhibit a transformed phenotype (clonal morphology and ability to plate in agar), when grown at 32 degrees C, their phenotype is normal. Conversion from the normal to the transformed phenotype and the reverse is possible by temperature shifts. Conversely of the BHK21 clone 13 cells, of the rat fibroblasts (R111) transformed by 4-nitroquinoline-N-oxide (NQN), some exhibit a transformed phenotype restricted by temperature while others are not restricted by temperature in the expression of transformation. A working hypothesis is proposed suggesting that the phenotype of cells transformed by chemical carcinogens may be determined by the nature of the chemical reaction with the cell DNA. "Alkylating" carcinogens cause prevalently point mutation in bacteria (of the base substitution kind); in the case of transformation of mammalian cells temperature-sensitive phenotypes will be obtained. "Frameshift" carcinogens cause frameshift mutation in bacteria and cells transformed by this class of carcinogens will exhibit a transformed phenotype unrestricted by temperature.

Animals↗
PubMed1975

Measurement of blood volume in the Indian mud eel Amphipnous cuchia (Ham.) (amphipnoidae; pisces).

The blood volume of 10 male and 8 female Amphipnous cuchia (Ham.) were measured through dilution technique method using Evans blue and sodium citrate as anticoagulant. This method was established against heparin. The mean total blood volume and the blood volume per 100 g of body weight for all the weight groups in male were 9.73 +/- 2.45 and 3.10 +/- 0.66, and in female were 10.34 +/- 2.78 and 3.13 +/- 0.66 respectively. The total blood volume of male and female fishes increase as an exponential function of its total body weight.

Animals↗
PubMed1972

An analysis of central adrenoceptors for control of cardiovascular function.

1. In dogs anaesthetized with pentobarbitone sodium, bradycardia with hypotension occurred on intracerebroventricular (i.c.v.) injection of noradrenaline (50-200 mug) or phenylephrine (100-400 mug), but tachycardia with hypotension occurred on i.c.v. injection of isoprenaline (100-200 mug).2. These cardiovascular responses were central effects, and from the results obtained after bilateral vagotomy, removal of both stellate ganglia and transection of the upper cervical cord, it was evident that the efferent nervous pathway for all these effects was the sympathetic nervous system.3. An i.c.v. injection of the alpha-adrenoceptor blocking agent phenoxybenzamine (10 mg) blocked the bradycardia and hypotension produced by noradrenaline or phenylephrine, and an i.c.v. injection of a beta-adrenoceptor blocking agent, either propranolol (2 mg) or N-isopropyl-p-nitrophenyl-ethanolamine (INPEA) (10 mg), blocked the tachycardia and hypotension produced by isoprenaline.4. The cardiovascular effects produced by i.c.v. injection of the three sympathomimetic amines could be reproduced in cross-circulation experiments in the recipient dog when the amines were injected into its head circulation, and the effects of noradrenaline and phenylephrine, but not those of isoprenaline, were abolished by the alpha-adrenoceptor blocking agent yohimbine (1 mg/kg) injected intravenously into the donor dog.5. It is concluded that the central alpha-adrenoceptors are concerned with bradycardia and the central beta-adrenoceptors with tachycardia, but that both receptors are concerned with hypotension.

Amino Alcohols↗
PubMedDate not supplied

Perinatal outcome in relation to mode of delivery in meconium stained amniotic fluid.

Meconium staining of the amniotic fluid is a common complication during labour. When facilities like electronic monitoring, foetal blood sampling are not available, it is difficult to decide whether labour should be allowed to continue or caesarean section should be done. Even when caesarean section is done, meconium aspiration syndrome (MAS) can still occur and considerable morbidity and mortality may result in the newborn. Amino infusion is being considered as useful in decreasing MAS and its sequelae. Before resorting to amino infusion, we decided to analyse the perinatal outcome in meconium stained liquor to compare whether early caesarean section offered any advantage. This is a retrospective study of 150 labours complicated by thick meconium stained liquor, during a 12 month period (1992-93).

Asphyxia Neonatorum↗
PubMedDate not supplied

Presence of cholinoceptors in mesencephalic raphe nuclei concerned in thermoregulation in rabbits.

The thermal effects of cholinomimetics and cholinoceptor blocking agents microinjected into mesencephalic nucleus raphe medianus (NRM) were investigated in rabbits to determine the nature and role of these cholinoceptors in thermoregulation. Microinjection of cholinoceptor agonists, carbachol and pilocarpine, into NRM resulted in significant hyperthermia which could be blocked by local pretreatment with chlorisondamine (a nicotinic receptor blocker) as well as by ethybenztropine (a muscarinic receptor blocker). Intracerebroventricular pretreatment with LM 5008 (serotonin reuptake blocker) significantly inhibited the carbachol-induced hyperthermia. Both nicotinic and muscarinic cholinoceptors are present in mesencephalic NRM which may be involved in thermoregulation in rabbits. Activation of these cholinoceptors in NRM results in hyperthermia which seems to be due to an inhibition of a serotonin sensitive hypothalamic heat loss mechanism.

Animals↗
PubMedDate not supplied

Effect of growth on lung transfer factor and its components.

Measurement of lung transfer factor for CO (TLCO) and its constituent components, viz. diffusion capacity across alveolar capillary membrane (Dm) and instant pulmonary capillary blood volume (Vc) were undertaken in 120 healthy non-smoker males by single breath technique. All the three parameters (TLCO, Dm, Vc) showed direct negative correlation with age. While TLCO and Dm showed a significant direct positive correlation with height, there was no correlation between VC and height. The degree of correlation increased when both age and height were used together than either of them alone for prediction of TLCO120. The prediction formulae (TLCO120 = 3.8 + 21 H (m)-0.308 A) using both age and height has regression value (R) of 0.6479 (p < 0.001).

Adolescent↗
PubMedDate not supplied

Response of lung transfer components to grades of smoking.

Pulmonary functions were studied in 50 healthy, asymptomatic, 20 to 47 years, male smokers along with 50 healthy non-smokers matched for age, height, socio-economic status and physical activity. Smokers consumed 2-30 cigarettes per day with duration of smoking ranging from 2 to 26 years. In smokers FEF, V75. PEF and MVV were significantly reduced whereas FRC was increased significantly. Pulmonary diffusion function as assessed by TLCO showed significant reduction. While Vc showed progressive decrease with increasing duration and quantity of smoking, DM increased in the beginning but gradually declined later. TLCO showed a better negative correlation with quantity than with duration of smoking even when the effect of other factors was excluded. Decrease in TLCO is probably due to bronchoconstriction and reflex vasospasm of pulmonary vasculature. Co-efficient of diffusion KCO was also decreased in smokers.

Adult↗
PubMedDate not supplied

Pulmonary functions in healthy females of Haryana.

Pulmonary functions including lung volumes and pulmonary diffusing capacity were assessed in 137 healthy female subjects, 18-52 years of age. The results were analysed by age-wise division of subjects in six groups. It was observed that there were wide variations in pulmonary function values from one individual to another depending upon age and height of the subjects. Majority of ventilatory functions attained maximum values by the age of 25 years while diffusion functions improved upto 35 years of age. Pulmonary functions showed better correlation with age and height as compared to weight. Taking into consideration age and height of subjects, regression equations for different pulmonary functions have been derived for female subjects.

Adolescent↗