Search PubMed⌕ Search

Biomedical subjects

A Mohan

Publications and source records attributed to A Mohan.

At least 55 records · Page 3Linked to original sources
PubMed1998

Matrices of paired substitutions show the effects of tRNA D/T loop sequence on Drosophila RNase P and 3'-tRNase processing.

Drosophila RNase P and 3'-tRNase endonucleolytically process the 5' and 3' ends of tRNA precursors. We examined the processing kinetics of normal substrates and the inhibitory effect of the tRNA product on both processing reactions. The product is not a good RNase P inhibitor, with a KI approximately 7 times greater than the substrate KM of approximately 200 nM and is a better inhibitor of 3'-tRNase, with a KI approximately two times the KM of approximately 80 nM. We generated matrices of substitutions at positions G18/U55 and G19/C56 (two contiguous universally conserved D/T loop base pairs) in Drosophila tRNAHis precursors. More than half the variants display a significant reduction in their ability to be processed by RNase P and 3'-tRNase. Minimal substrates with deleted D and anticodon stems could be processed by RNase P and 3'-tRNase much like full-length substrates, indicating that D/T loop contacts and D arm/enzyme contacts are not required by either enzyme. Selected tRNAs that were poor substrates for one or both enzymes were further analyzed using Michaelis-Menten kinetics and by structure probing. Processing reductions arise principally due to an increase in KM with relatively little change in Vmax, consistent with the remote location of the sequence and structure changes from the processing site for both enzymes. Local changes in variant tRNA susceptibility to RNase T1 and RNase A did not coincide with processing disabilities.

Animals↗
PubMed1998

Hyperinsulinemia and dyslipidemia in non-obese, normotensive offspring of hypertensive parents in northern India.

Insulin resistance contributes to initiation and acceleration of hypertension and atherosclerosis. This study attempted to detect occurrence of pre-hypertensive metabolic abnormalities, including hyperinsulinemia, in the offspring of hypertensive patients. Thirty-eight healthy offspring of hypertensive parents (group I, mean age 23.6+/-3.7 years) and 18 control offspring of normotensive parents (group II, mean age 24.2+/-2.8 years) were clinically examined, subjected to oral glucose tolerance test (OGTT), and the samples were analysed for blood glucose, insulin and lipid profile. Subjects in group I with fasting serum insulin <90 nmol/L constituted group Ia (n = 23, 62%) and those with >90 nmol/L constituted group Ib (n = 15, 38%). Both groups consisted of non-obese and normotensive subjects matched for body mass index and waist-hip ratio. There were no statistically significant differences in blood glucose levels between groups Ia, Ib and II during OGTT. Serum insulin levels during OGTT in group I were significantly higher than in group II (p<0.05), except at 30 min. Fasting insulin and 2 h post-OGTT insulin in group Ib were significantly higher than the other groups. Serum triglyceride levels, though within normal range, were higher in group I than group II (p<0.01). Similarly, high-density lipoprotein cholesterol levels in groups Ia and Ib were lower than those observed in group II (p<0.01). In conclusion, non-obese, normotensive offspring of hypertensive parents were observed to be hyperinsulinemic and dyslipidemic at an early age. These metabolic abnormalities may be associated with hypertension, glucose intolerance and accelerated atherosclerosis in adulthood.

Adult↗
PubMed1998

Relapse of Wegener's granulomatosis in the first trimester of pregnancy: a case report.

The association of Wegener's granulomatosis and pregnancy is rare and poses unique therapeutic challenges, particularly when active disease presents in early pregnancy. We describe a 22-yr-old woman who recovered successfully from her initial episode of Wegener's granulomatosis with a standard course of treatment with prednisolone and cyclophosphamide. Two and a half years later, she presented with relapse during the first trimester of pregnancy (primigravida). Since the clinical features suggested mild disease, she was started on prednisolone at a dose of 1 mg/kg/day, to which she seemed to respond very well for 3 months. Unfortunately, she had a spontaneous abortion at 5 months of gestation while on 25 mg/day of prednisolone. At this time, her disease flared further, with clinically manifest lung disease which was not part of her initial presentation. She was treated with another course of oral cyclophosphamide and prednisolone, and a remission was achieved in 4 months. There are no agreed guidelines on the treatment of Wegener's granulomatosis during pregnancy. In this report, the therapeutic issues are discussed against the background of the available literature.

Abortion, Spontaneous↗
PubMed1998

Clotting parameters in patients with adolescent idiopathic scoliosis undergoing posterior spinal fusion and instrumentation.

Thirty-six patients, 9 males and 27 females, average age 13.2 years, undergoing posterior fusion and segmental instrumentation surgery for idiopathic adolescent scoliosis were studied for abnormalities of platelet count (PC), prothrombin time (PT) and partial thromboplastin time (PTT). Intraoperative and immediate postoperative values were obtained at 2, 4, 6, 12, 24, and 48 hours. All patients showed diminution of platelet counts during the study period, but mean values were reduced below normals only at 4 hours after operation. The PT was significantly elevated in all patients intraoperatively and for the first 24 hours postoperatively, with return to normal by 48 hours. The PTT levels were essentially unaffected at any time.

Adolescent↗
PubMed1998

The relationship between bottle usage/content, age, and number of teeth with mutans streptococci colonization in 6-24-month-old children.

OBJECTIVES: Mutans streptococci (MS) are the primary pathogens involved in the development of early childhood caries. However, factors that may affect their acquisition in the mouths of young children are not well understood, and the period of initial colonization remains controversial. This study investigated the relationship of age, number of teeth, and bottle usage/content with regard to the isolation of MS in 6-24-month-old children. METHODS: A total of 122 children from low-income families attending a nutritional supplement program, and their mothers, participated in this study. Children were examined for dental caries and number of erupted teeth and were sampled for MS. Mothers were administered a questionnaire to obtain details of baby bottle use, including what food items were put in the bottle during the last week. RESULTS: MS was detected in more than one-third of the 6-24-month-olds. Unlike some studies that suggest a later period of infectivity, approximately 20% of children under 14 months of age, including 4 of 22 infants aged 6-9 months, were colonized with MS. When examined separately, age, number of teeth, and bottle usage/content were each found to be related to the presence of MS. Mutans streptococci colonization was more likely with increasing age and number of teeth, and children whose bottles contained sweetened beverages were more likely to be colonized than children whose bottles contained milk. Logistic regression models that controlled for both age and number of teeth indicated that children who consumed sweetened beverages in their baby bottle had a statistically significant, four-fold increase in the odds of colonization by MS relative to children who consumed milk. CONCLUSIONS: The finding that approximately 20% of the children under 14 months of age were infected with MS indicates that colonization in this sample of low-income preschool children may begin earlier than suggested by some investigations. Additionally, the risk of MS colonization appears lower among infants who consume milk rather than sweetened beverages in the bottle.

Age Factors↗
PubMed1997

Lipid peroxide, beta-carotene and alpha-tocopherol in ischaemic stroke and effect of exogenous vitamin E supplementation on outcome.

30 patients with CT proven infarct presenting within 24 hours of the acute event were included in the study with 20 age and sex matched controls. On day 1 and day 15 of stroke, levels of plasma lipid peroxide (oxidant) and plasma alpha-tocopherol and beta carotene (antioxidant) were estimated. The patients were randomly assigned to two groups, one group receiving 300 mg/day of vitamin E for 15 days. Neurological examination was conducted according to Mathew scale on day 1 and day 15 and rehabilitation assessment was done at day 15 and at 6 weeks according to Barthel Index. On day 1, the mean value of plasma lipid peroxidation in controls was 4.97 +/- 1.44 nmol/ml and in stroke patients 5.89 +/- 1.56 nmol/ml (p < 0.05). The plasma beta-carotene in controls was 2.35 +/- 1.09 mg/L while in stroke patients was 1.07 +/- 0.55 mg/L (p < 0.001) and plasma alpha-tocopherol in control 9.74 +/- 2.76 micrograms/ml as compared to 7.57 +/- 2.92 micrograms/ml in stroke patients (p < 0.02). Initially the plasma lipid peroxide levels are high and antioxidant levels are low in patients of ischemic stroke. Exogenous vitamin E supplementation does not have any significant effect on early neurological outcome but it does bring about significant changes in subsequent recovery and rehabilitation of patients of stroke.

Humans↗
PubMed1995

Polyarteritis nodosa presenting as perirenal hemorrhage.

Though renal involvement with microaneurysm formation is common in polyarteritis nodosa (PAN), spontaneous perirenal hematoma (SPH) is rare. We report a patient in whom SPH was the presenting manifestation of PAN. SPH is a potential life-threatening complication of PAN and its early recognition is emphasized.

Adult↗
PubMed1995

Bronchoalveolar lavage in pulmonary tuberculosis: a decision analysis approach.

We assessed the utility of bronchoalveolar lavage (BAL) in the diagnosis of pulmonary tuberculosis (PTB) in 50 consecutive HIV-negative patients with clinical and radiographic findings suggestive of PTB, but with negative microscopy for acid-fast bacilli (AFB) on sputum smear. Patients were grouped, using a scoring system, into relative likelihoods of having PTB (I-IV, in descending probability). Patients were started on anti-tuberculosis treatment according to the BAL results. Bacteriological diagnosis of PTB was confirmed in 22/50 BAL; 11 (91.6%), seven (37%) and four (40%) of groups I-III, respectively. In 13 cases, an early diagnosis of PTB was made by positive microscopy for AFB on BAL; an alternative diagnosis was made in six cases (bacterial pneumonia 4, carcinoma 2). A decision analysis model was created to assess the overall utility of BAL. This suggested that in a region of high PTB prevalence, and when the clinical diagnosis of PTB is likely, empirical treatment is the best course of action, with BAL being reserved for further investigation of non-responders. Early BAL should be considered when the diagnosis of PTB is uncertain.

Adolescent↗