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Biomedical subjects

R Mathur

Publications and source records attributed to R Mathur.

At least 145 records · Page 8Linked to original sources
PubMed1976

Cardiac innnervation in the prenatal stages of Anas poecilorhyncha.

Innervation of the heart has been observed in the progressive developmental stages of Anas poecilorhyncha ranging from 8 h to 14 days stages using silver impregnation technique of Ungewitter (1951). Vagal cardiac fibres reach the atrial wall on the fourth day. Migration of nerve cells and ganglia has been observed from the more anterior regions to the heart along the precaval veins. The adult pattern of the heart is first established at the 8 days stage while the traces of the endocardial cushions are still present. The atrioventricular valves show rich innervation. The subepicardial ganglia and simple myocardial plexuses appear in the 8 days stage and become well differentiated on the 10th day. The subendocardial plexuses are reported to be sensory for the testing of the properties of the blood while the myocardial plexuses seem to have motor control over the working muscles of the heart specially those of the atria where rich innervation is observed. Local reflex areas have been described.

Animals↗
PubMedDate not supplied

Influence of chelating agents on the toxicity and distribution of beryllium in rats.

The effect of two new chelating agents-Tiron (4,5-dihydroxy-1,3-benzene disulphonic acid disodium salt) and succinic acid--on the mobilization of beryllium was studied. Animals were exposed to beryllium nitrate (1 mg kg(-1) i.p.) daily for 21 days. Administration of beryllium nitrate showed a marked decrease in haemoglobin percentage, blood sugar, serum alkaline phosphatase and serum protein and a significant increase in the activity of transaminases. Tissue protein and glycogen contents and the activity of alkaline phosphatase, adenosine triphosphatase and succinic dehydrogenase showed significantly decreased values, but beryllium nitrate provoked a considerable increase in the activity of acid phosphatase and glucose-6-phosphatase in the vital and reproductive organs. Significant improvement in the haematological and biochemical parameters was observed with Tiron but no therapeutic effect was seen with succinic acid. Atomic absorption spectrophotometry (AAS) also showed a decreased level of beryllium concentration in the liver and kidney after Tiron therapy.

1,2-Dihydroxybenzene-3,5-Disulfonic Acid Disodium ↗
PubMedDate not supplied

Effects of zinc supplementation during chelating agent administration in cadmium intoxication in rats.

The concomitant administration of zinc during chelation of cadmium (Cd) with meso-2,3-dimercaptosuccinic acid (DMSA) or calcium trisodium diethylenetriamine penta-acetic acid (DTPA) was investigated in male rats subchronically exposed to Cd. The results suggest that the administration of zinc alone after cadmium exposure does not elicit any protective effects. However, when supplemented during treatment with DTPA it produced a significant turnover in the altered biochemical variables and a depletion of Cd concentration in liver and kidneys. Cadmium-induced elevated hepatic metallothionein (MT) contents remained practically unaltered on Zn-DTPA administration, but there was a significant increase in renal MT levels compared to rats administered Cd-DTPA or Cd alone.

Animals↗
PubMedDate not supplied

Beryllium-induced biochemical alterations and their prevention following co-administration of meso-2,3-dimercaptosuccinic acid or 2,3-dimercaptopropane sulphonate in rats.

The effects of meso-2,3-dimercaptosuccinic acid (DMSA) and 2,3-dimercaptopropane sulphonate (DMPS) on body beryllium burden, hepatic lipid peroxidation, glutathione, alkaline and acid phosphatase and some biochemical variables of porphyrin metabolism were studied in beryllium-poisoned rats. It was observed that beryllium poisoning is associated with a slight increase in lipid peroxidation, significant depletion of alkaline phosphatase and elevation of acid phosphatase activities in the liver and increased beryllium concentration in blood and other soft organs. Evidence is presented that both DMSA and DMPS during concomitant administration prevented most of the above beryllium-induced biochemical alterations. Tissue beryllium concentration and histopathological lesions in liver and kidneys were also significantly less marked following simultaneous administration of DMPS compared to beryllium-exposed controls; DMSA was comparatively less effective.

Animals↗
PubMedDate not supplied

Ear infection and infant feeding practices.

Feeding practices were studied in 128 infants aged 18 months and below with middle ear infection, belonging to the low socio-economic group. By the age of one year, 117 (91.4%) had acquired the infection. At the onset of the first episode, 105 (82.0%) were breast-fed, 42 not receiving any other milk. There were no differences in the feeding practices between infants who had single and those who had multiple episodes. Ninety-six infants were being given water by spoon or bottle and 42, semisolids by spoon. Among the 105 breast-fed infants, in 93 (88.6%), the infants' heads were often flat during feeding. In contrast, in the 86 infants on 'top' feeds 53 (61.6%) of the mothers said that they kept the infants' head raised during feeding. The difference was significant (x2 = 53.18, P less than 0.001). Mothers should avoid feeding infants with the latter's head flat, although the former may adopt any comfortable position.

Breast Feeding↗
PubMedDate not supplied

Non-hormonal post-coital contraceptive action of neem oil in rats.

Neem oil, a natural product of Azadirachta indica was investigated for various hormonal properties in relation to its post-coital contraceptive action. At subcutaneous doses up to 0.3 ml/rat, neem oil did not possess any estrogenic, anti-estrogenic or progestational activity and appeared not to interfere with the action of progesterone. These findings were confirmed using the histo-architecture of the uterus of treated rats. Since the post-coital contraceptive effect of neem oil seems to be non-hormonal, neem oil would be expected to elicit less side effects than the steroidal contraceptives.

Animals↗
PubMedDate not supplied

Gametogenic count and histopathological effect of thorium nitrate and uranyl nitrate on mice testes.

Daily intraperitoneal administration of aqueous solution of 0.05 m mole/100 g b. wt. of uranyl nitrate and thorium nitrate has been observed for 7 days. Marked reduction in the seminiferous tubule diameter and gametogenic count was observed. Signs of testicular necrosis, exfoliation of germ cells, and karyolysis and karyorrhexis were seen in most of the tutubles. Mononucleate and polynucleate giant cells were also observed indicating prolonged pathological condition.

Animals↗
PubMedDate not supplied

Antifertility effects of embelin in male rats.

Embelin, extracted from Embelia ribes Burm. berries, altered the testicular histology and glycogen, gametogenic counts and accessory sex gland fructose at the dose levels 0.3, 0.4 and 0.5 mg/kg body weight administered subcutaneously for 35 days. The compound is suggested to possess antiandrogenic activity.

Androgen Antagonists↗
PubMedDate not supplied

Adenosinergic and dopaminergic interaction in nigrostriatum in FeCl3-induced model of parkinsonism in rats.

The effect of adenosine modulating drugs was studied in the FeCl3-induced model of parkinsonism in rats. In rats bearing unilateral FeCl3 induced lesion of the dopaminergic nigrostriatal pathway, stimulation of adenosine receptors with adenosine, dose-dependently reduced the ipsilateral rotations induced by apomorphine. A specific agonist of adenosine A2A receptor, CGS-21680, also completely blocked the rotations while the specific A2 receptor antagonist, CGS-15943A, potentiated rotations induced by apomorphine. The nonspecific adenosine antagonist, theophylline (50 mg/kg i.p.) potentiated stereotype behavior although blocking rotations. This study provides evidence for a negative postsynaptic interaction between dopamine and adenosine receptors.

Adenosine↗
PubMedDate not supplied

Diagnosis and management of congenital adrenal hyperplasia: clinical, molecular and prenatal aspects.

Congenital adrenal hyperplasia (CAH) is the most common cause of female pseudohermaphroditism in Indian children. It is caused by enzymatic defects in the steroidogenic pathway of the adrenal glands and is characterized by impaired cortisol and aldosterone synthesis and overproduction of androgens. The disease usually presents with life-threatening problems and virilization, with long term physical and psychological effects. The clinical and laboratory diagnoses play an important role in deciding the course of treatment, which continues lifelong. To ensure proper growth and development of the patient, optimized disease management and treatment with steroids is required. Often the patient also requires surgical correction. Recent developments in molecular genetics have greatly helped in understanding the pathogenesis of the disease. The gene encoding for steroid 21-hydroxylase, CYP21, is located on the short arm of chromosome 6 in the HLA region and is amplified for genetic diagnosis. Rapid characterization of point mutations is possible using the allele-specific polymerase chain reaction technique in affected children. Counselling, prenatal diagnosis and treatment are recommended in all pregnant women with a positive family history to reduce or eliminate the effects in affected foetuses. This spares the female newborn the consequences of genital ambiguity and problems of gender identity.

Adrenal Hyperplasia, Congenital↗