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Biomedical subjects

R Ramachandran

Publications and source records attributed to R Ramachandran.

45 records · Page 3Linked to original sources
PubMed1993

Topical nitroglycerin prevents the pressor response to tracheal intubation and sternotomy in patients undergoing coronary artery bypass graft surgery.

Thirty adult patients who underwent coronary artery bypass graft surgery were allocated randomly to one of two equal groups to receive either 2% nitroglycerin, or a placebo ointment, applied topically over an area of 5 cm by 10 cm, in a double-blind manner, 1 h before induction of anaesthesia. Premedication consisted of oral diazepam 5-10 mg, intramuscular morphine 0.2 mg.kg-1 and promethazine 0.4 mg.kg-1. Anaesthesia was induced with morphine 0.15-0.2 mg.kg-1 and thiopentone 3-5 mg.kg-1. Laryngoscopy and tracheal intubation were facilitated by suxamethonium 1.5 mg.kg-1, and pancuronium 0.1 mg.kg-1 was used for subsequent muscle relaxation. Anaesthesia was maintained with 0.5% halothane and 40% oxygen in nitrous oxide. A significant increase in blood pressure occurred during and after laryngoscopy and tracheal intubation, and following midline sternotomy in the control group. These changes were absent in patients pretreated with topical nitroglycerin. The nitroglycerin group also maintained a lower rate-pressure product than the control group. We conclude that topical nitroglycerin is a simple and useful pretreatment to prevent the pressor response to tracheal intubation and midline sternotomy in patients undergoing coronary artery bypass graft surgery.

Adult↗
PubMed1990

Five year results of a 3-month and two 5-month regimens for the treatment of sputum-positive pulmonary tuberculosis in south India.

A controlled study of three short-course regimens was undertaken in South Indian patients with newly diagnosed, sputum-positive pulmonary tuberculosis. The patients were allocated at random to one of three regimens: a) Rifampicin, streptomycin, isoniazid and pyrazinamide daily for 3 months (R3); b) the same regimen as above but followed by streptomycin, isoniazid and pyrazinamide twice-weekly for a further period of 2 months (R5); c) the same as R5 but without rifampicin (Z5). A bacteriological relapse requiring treatment occurred by 5 years in 16.8% of 113 R3, 5.2% of 97 R5, and 20.0% of 115 Z5 patients with organisms sensitive to streptomycin and isoniazid initially. The differences in the relapse rates between the R3 and R5 regimens and the R5 and Z5 regimens were statistically significant (p less than 0.01 for both). Considering patients with organisms initially resistant to streptomycin or isoniazid or both, 7 of 52 patients (4 R3, 2 R5, 1 Z5) had a bacteriological relapse requiring retreatment.

Adolescent↗
PubMed1987

Pavlovian analysis of interactions between hunger and thirst.

In four experiments we examined the effect of an irrelevant drive on classical conditioning with food and water. In the first experiment the irrelevant drive weakened the conditioned response in extinction. In Experiments 2 and 3, this suppressive effect was found also in acquisition. Furthermore, the presence of an irrelevant drive during nonreinforced presentations of the conditioned stimulus was found to protect the conditioned response from extinction. Experiment 4 showed that the depressive effect of the irrelevant drive is manifested only when the relevant drive is present. Taken together, these results suggest that an irrelevant drive can influence conditioned responding by modulating the representation of the unconditioned stimulus.

Animals↗
PubMedDate not supplied

Orientational information from TEDOR spectral sidebands.

In a dipolar-coupled spin-1/2 network of the type 15N1-(13)C-15N2, an assessment of the sensitivity of the N --> C and C --> N TEDOR sideband intensities to the Euler angles defining the orientation of the two heteronuclear dipolar vectors in the 13C and 15N chemical shift (CS) tensor principal axes system has been carried out via numerical calculations. The results clearly indicate the potential of TEDOR MAS NMR spectroscopy for the characterization of the CS tensor orientation in the molecular frame. The efficacy of the method has been experimentally illustrated by TEDOR studies on a polycrystalline sample of [1, 3-(15)N2, 2-(13)C]uracil, which is one of the four bases in RNA.

Carbon Isotopes↗
PubMedDate not supplied

Propionic acidemia without acidemia: a case report.

Propionic acidemia is a recessively inherited disorder of organic acid metabolism characterized by a spectrum of clinical and biochemical findings. Metabolic acidosis is a key feature of this disease and is useful in differentiating it from nonketotic hyperglycinemia. This case report is presented because significant metabolic acidosis was not a prominent or persistent finding in this patient.

Acidosis↗