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Biomedical subjects

R C Ahuja

Publications and source records attributed to R C Ahuja.

At least 19 recordsLinked to original sources
PubMed1992

Oxygen transport through a model lung surfactant surface layer: influence of the film compression on the kinetics.

The influence of the compression state of a model Lung Surfactant Surface Layer LSSL on the oxygen permeation kinetics was studied in vitro at 37 degrees C. In an attempt to mimic in vivo conditions, the oxygen from the air was allowed to cross a dipalmitoylphosphatidylcholine DPPC layer situated at an air/deaerated saline interface in an electrochemical vessel. The time dependent concentration change of the oxygen diffusing through this layer into the deaerated saline hypophase was measured electrochemically using a Hanging Mercury Drop Electrode HMDE, situated at a definite depth in the bulk of the saline. The surface pressure in the monolayer was monitored using a Wilhelmy balance. The oxygen permeability was measured through two differently compressed DPPC layers in which the area/phospholipid molecule differed by 30%. This is consistent with the difference in the alveolar area at the end-points of the compressed and expanded lung. The results, submitted to a linear regression analysis, showed that the DPPC film compression influences the oxygen permeation kinetics. The denser the lipid film, the slower the oxygen uptake by the deaerated hypophase. The results suggest that the LSSL might play an important role in the oxygen transport kinetics, the oxygen permeation through it being dependent on the actual lung area.

1,2-Dipalmitoylphosphatidylcholine↗
PubMed1990

Intravenous streptokinase in the management of a subset of patients with unstable angina: a randomized controlled trial.

We report the results of a randomized controlled trial of intravenous streptokinase in a subset of patients with unstable angina. Seventy-six patients were admitted with prolonged (more than 20 minutes) angina at rest of less than 3 weeks onset. Fifty-two patients continued to have more than 3 episodes of prolonged angina in 48 hours on medical therapy with metoprolol, isosorbide dinitrate, nifedipine and intravenous nitroglycerin. Forty-eight patients consented to enter the study and were randomized into two groups. The first group, of 24 patients, received 1.5 million units of streptokinase infusion and the second group, also of 24 patients, received a placebo. Pain relief within 48 hours was achieved in 19/24 (79.1%) patients after streptokinase infusion as compared to 9/24 (37.5%) of the controls (P less than 0.05). Approximately 90% (17/19) of patients responding to streptokinase therapy were relieved of chest pain within the first six hours as against none in the controls. The incidence of acute myocardial infarction within six months was 12.5% (3/24) in those receiving streptokinase and 25% (6/24) in the controls. Mortality at six months stood at 8.33% (2/24) in the treated patients and 16.6% (4/24) in the controls. Intravenous streptokinase thus appears to be of benefit in patients with angina at rest of recent onset which does not respond to conventional medical therapy.

Angina Pectoris↗
PubMed1989

Clinical correlates of acute right ventricular infarction in acute inferior myocardial infarction.

Right ventricular infarction was diagnosed on the basis of ST-segment elevation greater than or equal to 1 mm in at least one right precordial lead (V3R-V6R) in 20 of 50 patients with first acute inferior myocardial infarction. Seventy five percent of these had ST elevation in 2 or more right precordial leads. Giddiness and hiccups were more common amongst such patients (P less than 0.05). Signs of right ventricular dysfunction-raised jugular venous pressure (65%), Kussmaull's sign (45%), hypotension (without cardiogenic shock, 40%) and right-sided third sound (25%) in the absence of clinical left ventricular failure, were noted in 65% of such patients. Eleven patients had 2 or more of the above signs. ST elevation in 2 or more right precordial leads was found in 10 of these 11 patients. A more complicated course in the hospital characterised by bradyarrhythmias, hypotension and cardiogenic shock, combined with a greater mortality was seen in such patients. We conclude that the bedside diagnosis of haemodynamically significant right ventricular infarction can be made on the basis of a combination of clinical signs and ST elevation in 2 or more right precordial leads, even in units not equipped for bedside haemodynamic monitoring, echocardiography and radionuclide studies. This should lead to a better identification and management of such patients.

Acute Disease↗
PubMed1989

Digoxin or verapamil or metoprolol for heart rate control in patients with mitral stenosis--a randomised cross-over study.

The effect and choice of a drug to control heart rate for symptomatic improvement in patients with isolated mitral stenosis with normal sinus rhythm (n = 10) or atrial fibrillation (n = 10) were studied. Digoxin (0.25-0.5 mg daily), metoprolol (50-100 mg twice a day) and verapamil (40-80 mg three times a day) were evaluated for this purpose. An open randomised cross-over design was followed. The efficacy of a drug was evaluated by: (1) subjective improvement on a visual analog scale, and (2) objective improvement on repeated multi-stage symptom-limited treadmill exercise. In patients with sinus rhythm greater than or equal to 50% subjective improvement was seen in 90%, 40% and nil with metoprolol, verapamil and digoxin, respectively. The total work done by these patients was 1008 +/- 541 kpm (control), 2869 +/- 1418 kpm on metoprolol, 2369 +/- 884 kpm on verapamil and 1654 +/- 918 kpm on digoxin. In patients with atrial fibrillation greater than or equal to 50% subjective improvement was seen in 80%, 40% and 30% with verapamil, metoprolol and digoxin, respectively. The total work done by these patients was 555 +/- 232 kpm (control), 1379 +/- 553 kpm on verapamil, 1251 +/- 575 kpm on metoprolol and 716 +/- 340 kpm on digoxin. The degree of improvement on a drug appeared to be a function of its ability to control resting and exercise heart rates in two different rhythms in these patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1989

Falciparum malaria--present day problems. An experience with 425 cases.

Clinical details and present day problems encountered in 425 cases of falciparum malaria (PF) are reported. 10.11% had taken chloroquine prior to reporting to us. Parasitic count done in 23.05% cases lacked correlation with severity of disease. Pattern of fever varied markedly but 5.4% were afebrile throughout and presented only with bodyache and malaise. Apyrexial spell was noted in 5.64%. 28.70% had typical facial looks of anaemia and sallow complexion. Cerebral symptoms were noted in 3.05%. Other symptoms were severe headache 33.4%, pain abdomen 3.29%, gastroenteritis 5.64%, jaundice 2.58% and bronchitis in 7.50%. We encountered subconjunctival haemorrhages with purpura and/or urticaria in four cases, symptoms suggestive of shock lung in 3, pulmonary oedema in 2, severe anaemia (HB less than 4 g%) in seven pregnant ladies, extrapyramidal symptoms in follow up period in 5 and congenital malaria in 2 cases. 83.25% were cured with chloroquine and oxytetracycline. 8.47% (who deteriorated despite the above treatment) were treated with quinine for 6 days. 5.17% (with severe disease) were also given quinine as first line drug. 2.82% (unresponsive to chloroquine and oxytetracycline but with mild disease) were treated with pyrimethamine-sulphamezathine combination for 5 days. One case who did not respond to quinine was treated with quinidine. Recrudescence was seen in 3.67% of patients treated with chloroquine and oxytetracycline. There was no case with renal failure, haemolysis due to G6PD deficiency and black water fever. There was only one death (0.23%) in our series. Self-medication, haphazard therapy and the slogan "Fever may be malaria-take chloroquine" can lead to problems in falciparum malaria.

Adolescent↗
PubMed1978

Leucocyte migration inhibition test in cases of ischaemic heart disease.

Cases of ischaemic heart disease have been studied for the cell-mediated immune response against human heart antigen by using the leucocyte migration inhibition test. In 30 cases of acute myocardial infarction, the leucocyte migration inhibition values started increasing from the first week reaching a peak in 3 to 4 weeks and then declining but still above control values 12 months after infarction. The leucocyte migration inhibition values were significantly higher than control values in another 10 patients with late complications of previous infarction and in those patients with acute myocardial infarction who were less than 40 years of age, who had extensive anterior infarction, or who had a past history of angina pectoris. The leucocyte migration inhibition values were negligible in all the 12 patients with stable angina pectoris, but were high in 2 of the 8 with unstable angina and in 3 of the 4 with the intermediate coronary syndrome. The leucocyte migration inhibition values were much higher in patients with complications, which may be the result of cardiac damage by a cell-mediated immune response.

Adult↗
PubMed1976

A double-blind trial of penbutolol: a new beta-receptor blocking agent in the treatment of angina pectoris.

A double-blind placebo controlled study of angina pectoris with penbutolol was undertaken in parallel groups in fifty-two patients. The duration of the study was six weeks. The dosage range for penbutolol was 8 mg to 50 mg per day. Six patients were dropped from the analysis. Seventeen patients (81%) in the penbutolol series exhibited a 50% reduction in anginal attacks, NTG consumption and subjective improvement. Significant reduction in nitrite intake was observed. Effort tolerance was improved significantly in those receiving penbutolol. Penbutolol was well-tolerated.

Adrenergic beta-Antagonists↗
PubMedDate not supplied

Cardioselective beta-blockade with atenolol and acebutolol following acute myocardial infarction: a multiple-dose haemodynamic comparison.

In patients with acute myocardial infarction the haemodynamic relevance of the ancillary pharmacological properties of cardioselectivity and of intrinsic sympathomimetic activity (ISA) possessed by beta-blocking drugs is unclear. The dose-response effects of atenolol and acebutolol, two cardioselective compounds, the latter also possessing a degree of ISA, were therefore compared in a single-blind, dose-response, crossover study in patients within 18 h of suffering an uncomplicated acute myocardial infarction. The logarithmic cumulative dosage schedule achieved plasma concentrations in the clinical therapeutic ranges for both atenolol (0.05 +/- 0.04-0.19 +/- 0.03 micrograms/ml) and acebutolol (0.22 +/- 0.14-0.8 +/- 0.29 micrograms/ml). Incremental doses of intravenous atenolol (cumulative, 1-8 mg) resulted in significant decreases in systolic blood pressure, heart rate, cardiac output, stroke volume, and stroke work index (p less than 0.01 for each). Pulmonary artery occluded pressure (p less than 0.05) and systemic vascular resistance (p less than 0.01) increased. Incremental doses of intravenous acebutolol (cumulative, 10-80 mg) also resulted in significant decreases in systolic blood pressure, heart rate, cardiac output, stroke volume, and stroke work index (p less than 0.01 for each). Systemic vascular resistance increased (p less than 0.01); there was no consistent change in the pulmonary artery occluded pressure. Within the limits of the experimental protocol, the additional property of ISA possessed by acebutolol resulted in no statistically significant haemodynamic differences from atenolol. This may reflect either an insufficient degree of ISA possessed by acebutolol to confirm the original hypothesis, or its haemodynamic irrelevance in the presence of the increased sympathetic tone that is frequently present following acute myocardial infarction.

Acebutolol↗
PubMedDate not supplied

Beta blockade for patients of mitral stenosis in sinus rhythm.

Twenty patients of isolated mitral stenosis in normal sinus rhythm (age 22 +/- 4 yrs) in whom symptoms of systemic and pulmonary congestion were controlled on diuretics were the subjects of the present study. The effects of addition of Metoprolol 50 mg po bid for 4 weeks on subjective and objective indices of exercise tolerance were evaluated. Metoprolol produced greater than 50% subjective improvement in 80% of these patients. The increase in time to dyspnoea and total work done on treadmill after 90-120 mins, and after 12 hrs of a dose of metoprolol, were both significant (p less than 0.01). In none of the patients, resting heart rate less than 50/mt, resting and exercise systolic BP less than 90 and less than 105 mmHg, respectively, or any important untoward effects were observed. Metoprolol's beneficial effects and safety can be judged in these patients at two hours after first dose in out patients clinic.

Heart Rate↗