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Biomedical subjects

N Mishra

Publications and source records attributed to N Mishra.

At least 19 recordsLinked to original sources
PubMed1991

Extracranial carotid artery aneurysms following accidental injury: ten years experience.

Extracranial carotid artery aneurysms secondary to accidental injury are rare. We have seen eight lesions of this type in the last 10 years. The aneurysm was produced by blunt trauma in four patients, penetrating shrapnel injury in two, stabbing and electrical injury in one each. The left side was involved in seven patients. The internal and common carotid artery were each involved in four patients and the lesion was unilocular in five. These lesions often produce non-specific symptoms and may mimic neoplastic or inflammatory masses: a mistaken diagnosis of tonsillar abscess in one patient resulted in incision and drainage before an intravenous digital subtraction angiogram (IV-DSA) correctly identified the abnormality. IV-DSA is ideal for pre-operative assessment of these patients. Awareness of these lesions is essential since definitive surgical repair is possible. All patients in the present study underwent successful surgical repair.

Adolescent↗
PubMed1991

An experimental evaluation of possible teratogenic potential in Boerhaavia diffusa in Albino rats.

The present study was undertaken to evaluate any possibility of teratogenic effects in Boerhaavia diffusa (Punarnava), a widely used herbal medicine for renal and urinary tract diseases by Ayurvedic physicians in India. The ethanolic extract of Boerhaavia diffusa (BDE) was administered daily in a dose of 250 mg/kg, body weight p.o., to pregnant albino female rats during the entire period of gestation. BDE was found to be devoid of any teratogenic effect as litter size and survival rate of foetuses were the same as for the normal control group and no foetal anomaly could be detected.

Animals↗
PubMed1991

Effect of exercise on lung transfer factor for CO in smokers.

The lung transfer factor for carbon monoxide was studied in 24 apparently healthy smokers and in 24 well-matched non-smokers at rest and during exercise. Single-breath and steady state (TLcoss) transfer factors for carbon monoxide, the Krogh constant, and the capillary blood volume were significantly lower in smokers. Exercise increased minute ventilation to a similar extent in both groups, but significantly lower values of TLcoss were measured in smokers than in non-smokers during mild and moderate grades of exercise (p less than 0.001). This difference in TLcoss may be attributed either to the difference in capillary blood volume or to increased inhomogeneities with regard to alveolar ventilation and perfusion due to airway damages in smokers, or to both factors.

Adult↗
PubMed1991

Lung transfer components in hyperthyroidism.

Pulmonary functions were studied in twenty hyperthyroid non smoker patients. Their FVC, PEFR and MVV were significantly lowered while FEV1/FVC% and EFR25-75% were normal. Amongst the diffusion functions, Tlco, Dm and VA were reduced and VC increased, though these changes were not statistically significant. After the achievement of euthyroid state, statistically significant increase was seen in FVC, PEFR, MVV, Tlco120, Dm and VA with significant decrease in Vc from the basal levels. FEV1/FVC% and EFR25-75% were not affected. These observations suggest that the principal abnormalities in pulmonary functions in the hyperthyroid state are increased pulmonary capillary blood volume and respiratory myopathy, which are reversed as euthyroid state is achieved.

Adult↗
PubMed1991

Effect of salbutamol on pulmonary diffusion functions in asymptomatic smokers.

Pulmonary functions including transfer factor for CO and its components (TIco, Dm, Vc) were studied in 45 asymptomatic subjects (25 smokers, 20 non smokers) using single breath technique. Ventilatory functions of smokers were significantly reduced; these improved significantly after salbutamol inhalation but most still remained lower than in non smokers. VA and Dm were marginally higher while Vc was significantly reduced in smokers. Their TIco1(20) was influenced only insignificantly. However, after salbutamol, both Dm and Vc were significantly lowered, resulting in further reduction (p 0.01) of TIco120 in smokers. The effect of salbutamol in non smokers was insignificant.

Adult↗
PubMed1990

Evidence for the inhibitory effect of 5-hydroxytryptamine at central and peripheral sites on ovulation in rabbits.

1. The effect of 5-hydroxytryptamine (5-HT) has been investigated on ovulation per se as well as on induced ovulation in rabbits. 2. 5-HT administered intracerebroventricularly (i.c.v.) did not induce ovulation per se. 3. The ovulation was induced by coitus, subcutaneous administration of progesterone and intravenous administration of cupric acetate. 4. Postcoital and progesterone induced ovulation was found to be blocked by i.c.v. administered 5-HT. 5. Cupric acetate induced ovulation was, however, not found to be blocked by i.c.v. administered 5-HT. 6. Intraperitoneal administration of 5-HT was found to block cupric acetate induced ovulation. 7. It is concluded that 5-HT exerts an inhibitory control over ovulation by acting at central as well as at peripheral sites in rabbits.

Animals↗
PubMed1990

Effect of cold challenge on alveolar capillary blood volume in normal individuals.

The effect of immersion of both the hands and the feet in water at 10 degrees C on lung transfer factor for carbon monoxide (Tlco) and on pulmonary capillary blood volume (Vc) was investigated in 20 normal young adult males immediately, 60 min and 120 min after the end of the cold challenge. Vc was significantly reduced immediately and the reduction was aggravated at 60 min. Tlco was significantly reduced only at 60 min. All the values returned to baseline at 120 min. It is concluded that the cold-induced changes in Tlco and Vc are physiological responses and not unique to patients with Raynaud's phenomenon as suggested by some workers.

Adult↗
PubMed1990

Diurnal variations in lung transfer factor and its components.

Serial measurements of transfer factor of lung and its constituent components along with FVC and EFR25-75% were undertaken in 20 healthy nonsmoker adult males thrice on the same day. All the lung transfer components decreased as the day advanced, though reduction was statistically significant for Tlco and VA only. These changes were present in association with reduction in FVC and EFR25.75% indicating that patency of airways influences diffusion function of lung. Variations during the day are less than 7.4% and are hence unlikely to influence their diagnostic value, but serial estimation of these functions should preferably be carried out at the same time specially in the morning when these values are maximum.

Adult↗
PubMed1986

Nervous system in Olveria indica, a rumen paramphistome (Digenea) of bovines, as revealed by non-specific esterase staining.

On the basis of esterase localization the complete nervous system has been visualized in Olveria indica Thapar & Simha, 1945, a paramphistome from the rumen of cattle, recorded for the first time from the north-east region of India. The basic number of posterior longitudinal nerves (i.e., 3 pairs) is the same as in other paramphistomes; four pairs of anterior longitudinal nerves are present, there being an extra pair of pharyngeal nerves. Conspicuous differences in the innervation patterns were observed, mainly in the innervation of the genital atrial region and acetabulum. The presence of prominent longitudinal connections, joining the anterior and posterior dorsal nerves and the anterior and posterior ventral nerves on either side, is a feature not hitherto found in other paramphistome species. The details of the course of all the nerves and their branches are discussed.

Animals↗
PubMed1985

A comparison of alpha 2-adrenoceptor regulation in brain and platelets.

Functional responses and alpha 2-adrenoceptor radioligand binding were studied in brain and platelets of rabbits under a variety of circumstances. The effects of oestrogen treatment and maturation were studied in female rabbits and of aging and amitriptyline treatment in male rabbits. No correlation was found between changes in brain and platelets either in response or alpha 2-adrenoceptor ligand binding under any of the conditions examined.

Aging↗
PubMed1985

The effects of sexual maturation on alpha-adrenoceptors in female rabbits.

alpha-Adrenoceptor number and function were examined in brain, platelets, and other peripheral tissues of young (2-3 months) and mature (6-8 months) non pregnant female rabbits. alpha1-Adrenoceptor number was significantly higher in forebrain, hindbrain, spleen and heart of mature rabbits. alpha2-Adrenoceptor number, on the other hand, was found to be significantly lower in platelets, forebrain and spleen but not changed in hindbrain and kidney of mature animals compared to young females. There was a significant reduction in platelet aggregation with maturation. However, no change in in vivo pressor or depressor responses to alpha-adrenoceptor agonists was observed in vivo.

Adrenergic alpha-Agonists↗
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↗
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↗