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Biomedical subjects

G Arora

Publications and source records attributed to G Arora.

9 recordsLinked to original sources
PubMed1994

Purification and characterization of an aminopeptidase from Lactobacillus casei subsp. rhamnosus S93.

An aminopeptidase of broad specificity was extracted by cell lysis of a selected strain of Lactobacillus casei subsp. rhamnosus during the late exponential phase. The enzyme was purified 195-fold from crude extract by using an f.p.l.c. system. Native and SDS/PAGE of the purified enzyme showed a single protein band of 89 kDa. The maximum aminopeptidase activity was observed at pH 7.0 and 39 degrees C. The enzyme hydrolysed a range of nitroanilide-substituted amino acids, as well as dipeptides, and accounted for most of the aminopeptidase activity found in cell-free extracts. The enzyme activity was inhibited by metal chelators such as EDTA and 1,10-phenanthroline. Cobalt ions only stimulated aminopeptidase activity and were also able to re-activate the enzyme previously inhibited by metal chelators. The Km and Vmax. values of the aminopeptidase for leucine p-nitroanilide were 0.06 mM and 12.6 mmol/min per mg of protein respectively. This enzyme was stable over the pH range of 5-9 and below 45 degrees C.

Amino Acids↗
PubMedDate not supplied

Severe supravalvar aortic stenosis in familial homozygous hypercholesterolemia.

Familial homozygous hypercholesterolemia is a rare disease with diverse clinical presentations. Patients often present with cutaneous xanthomas, particularly in the Achilles' tendon. They may have significant cardiovascular involvement, including premature atherosclerotic coronary artery disease and valvar and supravalvar aortic stenosis. Standard therapy includes diet modulation, pharmacotherapy, and lipid apheresis. Rarely, patients require surgical intervention for coronary artery bypass grafting and/or relief of the aortic stenosis. We present the case of a patient with severe progressive supravalvar aortic stenosis that ultimately required surgical resection despite aggressive medical therapy.

Aortic Stenosis, Supravalvular↗
PubMedDate not supplied

Studies on the male antifertility agent--gossypol acetic acid. III. Effect of gossypol acetic acid on rat testis.

Gossypol acetic acid at the dose of 5 mg/rat/day for 2 and 4 weeks did not cause any significant effect on the body weight, testis, epididymis, seminal vesicle and prostate weight, nor gossypol treatment had any significant effect on the activities of acid phosphatase and succinic dehydrogenase in the testis. Changes in the testis ATPase activity were, however, significant after gossypol treatment. During the course of present investigations no effect of gossypol treatment on 3H thymidine incorporation into DNA of testicular cells was observed, nor there were any changes in the DNA and total protein content of the testis after gossypol treatment. Gossypol treatment did not cause any effect on the plasma Na+ level. However, transient decrease in the plasma K+ level was observed; decrease in K+ level two weeks after gossypol treatment was restored to normal after 4 weeks of gossypol treatment. No changes in the histology of the testis were observed 2 weeks after gossypol treatment but marked inhibition of spermatogenesis was observed 4 weeks after gossypol treatment. Motility of vas deferens spermatozoa was also markedly inhibited 4 weeks after gossypol treatment. In the light of the present observations and those of others, there is a clear demonstration that gossypol acts directly on the spermatozoa and on the testis; at both the sites the drug interferes in the ATPase activity.

Adenosine Triphosphatases↗
PubMedDate not supplied

Systematic errors in bone-mineral measurements by quantitative computed tomography.

Bone-mineral measurements using quantitative computed tomography (QCT) are commonly based on comparisons with solutions in water of known concentrations of K2HPO4. In this paper are described theoretical and experimental studies that have led to the conclusion that large systematic errors can arise in these measurements, depending on the soft-tissue and fat concentrations in the vertebral spongiosa. In the case of single energy scanning, such large errors have been identified to be due to the varying water content (displacement effect) in the calibration samples and the varying fat content in the region of interest (ROI) within the patient. In the case of dual energy scanning, the error arises because when normalized to that of water, the mass attenuation coefficient of fat increases with photon energy while the reverse is true for K2HPO4. Our studies have also revealed that total trabecular bone density (which includes the mineral, soft tissue, and fat) can be much more accurately determined by the dual energy QCT method than bone mineral alone. This finding is especially interesting since there have been several reports in the literature suggesting that bone density rather than bone-mineral content is a better predictor of the risk of osteoporosis-related fractures.

Adipose Tissue↗
PubMedDate not supplied

A radioimaging technique for quantifying regional myocardial blood flow.

We developed a radioimaging technique for measuring regional myocardial blood flow (rMBF) in 5 mm2 myocardial tissue using canine closed-chest models. RMBF was measured in three groups: (1) total occlusion of left anterior descending (LAD) coronary artery with microfibrillar collagen, (2) fixed stenosis of LAD with angioplasty balloon, and (3) comparison of clinical dose response of adenosine (AD) and dipyridamole (DP) on rMBF. In these studies, rMBF in every 5 mm2 tissue was measured throughout the epicardium and endocardium. In groups 1 and 2, rMBF was also measured during adenosine-induced coronary hyperemia (ADICH). In group 1 (n = 7), rMBF measured at 6 hours post-LAD occlusion in epicardial infarct center (IC), peri-infarct (PI) and normal zone (NZ) were 17 +/- 7, 55 +/- 8, and 132 +/- 12 ml/min/100 tissue, respectively. The area and location of infarct seen in TTC staining matched with rMBF images. During ADICH, the corresponding rMBF were 16.2 +/- 13.9, 98.3 +/- 53.0, and 226.0 +/- 103.6 ml/min/100 g tissue, respectively. RMBF measured during ADICH in group 2 (n = 4) in areas of LAD stenosis (LS), surrounding stenosis (SS), and no stenosis (NS) were 120 +/- 58, 249 +/- 123, and 432 +/- 181 ml/min/100 gm tissue, respectively. In group 3, rMBF measured during 3 min into 0.14 mg/kg/min adenosine infusion in areas perfused by LAD, circumflex (CX) and right coronary artery (RCA) were 244 +/- 22, 238 +/- 19, and 215 +/- 19 ml/min/100 g tissue, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenosine↗