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Biomedical subjects

A Jain

Publications and source records attributed to A Jain.

At least 307 records · Page 17Linked to original sources
PubMed1991

Spectrophotometric determination of ascorbic acid in pharmaceuticals by background correction and flow injection.

Background correction has been shown to be an effective and indispensable modification in the spectrophotometric determination of ascorbic acid. The decomposition of ascorbic acid in pharmaceutical samples was carried out by incubation with sodium hydroxide to give products that were insensitive to ultraviolet light. The rapid oxidation in air of ascorbic acid, especially in dilute solutions, was avoided by the use of the flow injection principle for spectrophotometric determination and by employing a carrier stream of an anti-oxidizing nature consisting of 6 micrograms ml(-1) of 2-mercaptoethanol in 0.25% sulphuric acid. The optimized method with a single channel manifold made use of a carrier stream flow rate of 1.1 ml min(-1), an injection volume of 50 microl, a delay coil of 50 cm (0.5 mm i.d.) and detection at 245 nm. The throughput was at least 180 injections h(-1). The proposed flow injection method yielded results for the analysis of 0-20 micrograms ml(-1) of ascorbic acid that were 99-102% (relative standard deviation 0.6% or better) in agreement with those produced by comparable methods involving titration with iodine, chloranil or 2,6-dichlorophenolindophenol [4-(2,6-dichloro-4-hydroxyphenylimino)cyclohexa-2,5-dieno ne], and high-performance liquid chromatography. When the agreement was not good (as low as 14% with respect to the method being compared), this was traced to the presence of substances which are known to interfere in one or other of the methods of comparison.

Ascorbic Acid↗
PubMed1991

The effect of graft function on FK506 plasma levels, dosages, and renal function, with particular reference to the liver.

Plasma FK506 was studied in 49 liver, 13 heart, 3 double-lung or heart-lung, and 21 kidney recipients. The levels were correlated with the drug doses used, kidney function, and liver function. In all varieties of recipients, there was an early rise in the FK506 plasma levels that occurred at the time of intravenous administration of the drug. At the same time or shortly after, there were increases in serum creatinine that were transitory except in liver recipients with continuing suboptimal graft function. The quality of hepatic function dominated all aspects of FK506 management in the liver recipients. Those who received well-functioning grafts could be given about the same drug doses as recipients of kidneys and the thoracic organs. Liver recipients with defective grafts had astronomical rises in plasma FK506, a high incidence of renal failure, and probably increased neurotoxicity. In kidney transplant recipients, the FK506 plasma levels and doses were essentially the same in patients with prompt versus delayed renal function. These studies have highlighted the necessity, first, of close pharmacologic monitoring of patients who are given FK506 in the presence of abnormal liver function, and second, of using smaller intravenous induction doses than in past practice.

Adolescent↗
PubMed1991

An Indian hospital study of viral causes of acute respiratory infection in children.

From Sept. 1986 to Jan. 1989, a hospital-based study was conducted on 736 children, under 5 years of age, with acute respiratory infection. Nasopharyngeal secretions were examined for viruses by culture and by immunofluorescence. Viruses were detected in 22% of specimens: respiratory syncytial (5%), parainfluenza (5%), influenza A (4%), influenza B (2%), adenovirus (3%), measles (3%). The highest rates of detection were with patients diagnosed clinically as pneumonia or upper respiratory tract infection. The case fatality rate was very high (43%) in children with measles virus infection.

Child, Preschool↗
PubMed1991

Protein losing enteropathy as a manifestation of Henoch-Schönlein purpura.

Gastrointestinal manifestations of Henoch-Schönlein purpura (HSP) commonly include abdominal pain and gastrointestinal bleeding. Hypoproteinemia and edema could be related to renal involvement. We report a 14-year-old boy with classical features of HSP manifestated with edema due to severe intestinal protein loss, measured by elevated fecal alpha 1 antitrypsin secretion. The protein losing enteropathy subsided with corticosteroid therapy.

Adolescent↗
PubMed1991

Comparison of coronary angiographic features and oral dipyridamole thallium 201 tomography.

Coronary angiography and left ventriculography is commonly used to identify those patients with incomplete infarctions and therefore, a need for revascularization. The authors compared coronary angiography and left ventriculography with thallium 201 tomography using oral dipyridamole to identify patients with potential ischemia in the infarct zone indicating viable tissue. Forty-five patients (37 men, 8 women) with acute myocardial infarctions (29 anterior, 16 inferior) who received intravenous thrombolytic therapy were studied. On the basis of the left ventriculograms, only 16 patients were judged to have residual function in the infarct zone. Six of these patients had no thallium redistribution in the infarct zone, indicating lack of residual ischemia. Of the 29 patients with no residual function in the infarct zone, 18 had redistribution in the infarct zone, suggesting residual ischemic myocardium and thus viable tissue. Among the 32 patients with open infarct vessels, 15 had no redistribution in the infarct zone, but of the remaining 13 patients with occluded infarct vessels, 9 had redistribution in the infarct zone indicating residual ischemia and thus viable tissue. The authors' data suggest that neither wall motion analysis by left ventriculography nor the angiographic status of the infarct vessel identifies those patients with residual ischemia as evidenced by thallium tomography using oral dipyridamole.

Adult↗
PubMed1991

Left main coronary artery and femoral artery vasospasm associated with cocaine use.

A woman had diffuse vascular spasm related to cocaine use. She presented with evidence of an acute anterior myocardial infarction but had no rise in creatinine phosphokinase levels. Cardiac catheterization showed 90 percent proximal left main coronary artery narrowing. The catheterization was complicated by right femoral artery spasm. A repeat catheterization after treatment with nitroglycerin and diltiazem showed 30 percent proximal left main coronary artery narrowing. This catheterization was complicated by left femoral artery spasm. An exercise treadmill test was negative for ischemia.

Adult↗
PubMed1991

Relation between mixed venous oxygen saturation and cardiac index. Nonlinearity and normalization for oxygen uptake and hemoglobin.

The ability of mixed venous oxygen saturation (SvO2) monitoring to reflect changes in cardiac index (CI) with therapy in critically ill patients is unclear. To this end, SvO2 and CI were measured before and during an infusion of enoximone and/or dobutamine in 30 patients with advanced heart failure. A nonlinear relationship was observed between SvO2 and CI with the nonlinear correlation coefficient being 0.52. On normalizing for individual differences in hemoglobin and oxygen consumption, this correlation coefficient became 0.90. Further analysis of individual data was performed using linear regression, and the slopes and correlation coefficients were found to span a wide range slope: -10.0 to 30.9 min-m2/L, r: -0.27 to 0.99). However, the mean slope and correlation coefficient for patients with baseline CI and SvO2 less than 21/min/m2 and less than 55 percent were 18.3 min-m2/L and 0.87, respectively, while those for the remainder of patients were only 3.1 min-m2/L and 0.42, respectively. Thus, the nonlinear correlation coefficient of the SvO2-CI relationship in a group of patients is dependent on the homogeneity of their oxygen consumption and hemoglobin concentration. Furthermore, the ability of SvO2 to serve as a therapeutic indicator in any given patient is dependent on baseline SvO2 and CI.

Adult↗
PubMed1991

One hundred ten consecutive primary orthotopic liver transplants under FK 506 in adults.

An account is given of the 6- to 12-month survival, and causes of failure in 110 consecutive patients who underwent primary liver transplantation under treatment from the outset with FK 506 and steroids. The patient survival is 92.7%, and the first graft survival is 87.3%. At a very high frequency, the patients achieved good graft function, and they had a relatively low morbidity that was partially ascribable to minimal use and early discontinuance (in 60% of cases) of steroids. Renal dysfunction and other adverse findings were largely confined to patients with poor initial graft function and consequent apparent alteration of the kinetics of FK 506 elimination, causing functional overdosage. Results compare very favorably with our past record using conventional immunosuppression, and support the belief that FK 506 is a superior immunosuppressive agent which is suitable for chronic administration.

Adult↗
PubMed1991

The question of FK 506 nephrotoxicity after liver transplantation.

Formal studies have not been published on the nephrotoxicity of FK 506 when the drug was used from the outset. This kind of information was sought in 101 recipients of primary livers, 24 hearts, and 3 double lungs or heart-lung. Perioperative renal dysfunction was commonly seen, which appeared to be related to FK 506 doses and plasma levels, particularly when the drug was given IV. This was reversible. Late renal function has been generally satisfactory in all three cohorts of patients, and the incidence of hypertension has been low. The therapeutic index of FK 506 is a good one, as revealed by these observations in patients whose most notable achievement was a low mortality.

Anti-Bacterial Agents↗