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Biomedical subjects

A Jain

Publications and source records attributed to A Jain.

At least 271 records · Page 15Linked to original sources
PubMed1993

Percutaneous coronary angioscopy: applications in interventional cardiology.

We performed percutaneous coronary angioscopy in 35 patients to study the surface morphology of coronary artery lesions. Twenty-five patients had angioscopy performed in conjunction with PTCA, including 20 patients with de novo lesions (16 patients with unstable angina, four patients with stable angina), and five patients with restenosis lesions. Ten cardiac transplant patients had angioscopy performed in conjunction with annual follow-up angiography in attempt to identify accelerated atherosclerotic lesions. There were no complications of angioscopy in any patient. There were no intracoronary thrombi seen either by angiography or angioscopy in the stable angina patients. In the unstable angina group, angiography identified thrombus in 2 out of 16 (12.5%) versus 15 out of 16 (94%) (P less than 0.001) with angioscopy. Following angioplasty, dissections were seen angiographically in 7 out of 16 (44%) of patients versus 16 of 16 (100%) of the patients by angioscopy (P less than 0.01). Restenosis lesions were characterized by a white, fibrous appearance instead of the usual yellow color of primary atherosclerotic lesions. In the ten cardiac transplant patients, angioscopy appeared to be more sensitive than angiography for the detection of atherosclerosis. Yellow (atherosclerotic) and white (fibrotic) plaques were seen in the transplant patients, which often were not detected by angiography. In summary, angioscopy is an excellent tool for visualizing the surface morphology of coronary artery lesions. The clinical indications for angioscopy remain undefined at present.(ABSTRACT TRUNCATED AT 250 WORDS)

Angioplasty, Balloon, Coronary↗
PubMed1993

Differential regulation of intracellular glucose metabolism by glucose and insulin in human muscle.

Insulin and glucose stimulate glucose uptake in human muscle by different mechanisms. Insulin has well-known effects on glucose transport, glycogen synthesis, and glucose oxidation, but the effects of hyperglycemia on the intracellular routing of glucose are less well characterized. We used euglycemic and hyperglycemic clamps with leg balance measurements to determine how hyperglycemia affects skeletal muscle glucose storage, glycolysis, and glucose oxidation in normal human subjects. Glycogen synthase (GS) and pyruvate dehydrogenase complex (PDHC) activities were determined using muscle biopsies. During basal insulin replacement, hyperglycemia (11.6 +/- 0.31 mM) increased leg muscle glucose uptake (0.522 +/- 0.129 vs. 0.261 +/- 0.071 mumol.min-1 x 100 ml leg tissue-1, P < 0.05), storage (0.159 +/- 0.082 vs. -0.061 +/- 0.055, P < 0.05), and oxidation (0.409 +/- 0.080 vs. 0.243 +/- 0.085, P < 0.05) compared with euglycemia (6.63 +/- 0.33 mM). The increase in basal glucose oxidation due to hyperglycemia was associated with increased muscle PDHC activity (0.499 +/- 0.087 vs. 0.276 +/- 0.049, P < 0.05). However, the increase in leg glucose storage was not accompanied by an increase in muscle GS activity. During hyperinsulinemia, hyperglycemia (11.9 +/- 0.49 mM) also caused an additional increase in leg glucose uptake over euglycemia (6.14 +/- 0.42 mM) alone (5.75 +/- 1.25 vs. 3.75 +/- 0.58 mumol.min-1 x 100 ml leg-1, P < 0.05). In this case the major intracellular effect of hyperglycemia was to increase glucose storage (5.03 +/- 1.16 vs. 2.39 +/- 0.37, P < 0.05). At hyperinsulinemia, hyperglycemia had no effect on muscle GS or PDHC activity.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1993

Recent advances in hepatic transplantation at the University of Pittsburgh.

FK506 undoubtedly improved the survival advantage of hepatic allotransplantation. Hepatic-intestinal and multivisceral transplantation has also become a feasible therapy for patients with combined intestinal and liver failure. With better understanding of the immunologic and metabolic aspects of allo- and xenotransplantation, further clinical attempts to transplant animal organs to humans may be considered with the hope for a better outcome in the very near future.

Academic Medical Centers↗
PubMed1993

Therapy for congestive heart failure in the late 20th century.

Ten to 15 years ago, the thrust of research in the treatment of congestive heart failure centered around finding new inotropic agents. While initially useful, these agents given chronically actually accelerated left ventricular failure and were associated with excess mortality. Recently, it has been learned that altering the body's response to heart failure is more beneficial compared to attempts to stimulate left ventricular inotropic function. Such altering of the neurohumoral responses to heart failure has been associated with improvements in both morbidity and mortality.

Adrenergic beta-Antagonists↗
PubMed1993

Delta virus infection in cirrhotics in a north Indian hospital.

Forty patients of HBV related cirrhosis of the liver were studied for the presence of delta infection and subsequently the clinical features, course and outcome of these delta infected cases was compared with those of delta uninfected cases. Out of 40 patients studied, only four patients (10%) were reactive for anti-delta antibodies. The incidence of delta infection was common in the younger age group (31.25 +/- 4.78 years) as compared to the older age group (48 +/- 7.25 years) at p < 0.001. Hepatic Encephalopathy was seen in only 13.88% of delta negative patients as compared to 75% of delta infected patients (p < 0.05). During follow up period of 1 year, 75% of patients died in the delta virus infected group as compared to 22.22% in the delta negative group. The mortality was significantly higher in Child's class C (P < 0.01). So delta virus infection is associated with a more severe course of illness and a poorer prognosis in HBV related cirrhotics.

Adolescent↗
PubMed1992

Ascorbic acid prevents oxidative stress in glutathione-deficient mice: effects on lung type 2 cell lamellar bodies, lung surfactant, and skeletal muscle.

Glutathione deficiency in adult mice leads to lung type 2 cell lamellar body and mitochondrial damage; as reported here, these effects are associated with marked decrease of the levels of phosphatidylcholine (the main component of lung surfactant) in the lung and the bronchoalveolar lining fluid. Severe mitochondrial damage was also found in skeletal muscle. Treatment with ascorbate (1-2 mmol per kg of body weight per day), which led to greatly increased (approximately 2-fold) levels of lung and muscle mitochondrial glutathione, prevented damage to lamellar bodies and mitochondria as well as the decline of phosphatidylcholine levels in lung and alveolar lining fluid. The findings indicate that glutathione deficiency leads to depletion of lung surfactant and that this can be prevented with ascorbate. Administration of ascorbate spares glutathione and prevents cellular damage. Lamellar body degeneration in glutathione deficiency appears to be associated with oxidative damage to the perilamellar membrane, which contains the enzymes required for phosphatidylcholine synthesis. It is notable that although severe glutathione deficiency is lethal to newborn rats, which apparently do not synthesize ascorbate, adult mice are better able to survive such a deficiency because they can synthesize ascorbate. The present studies, which suggest that high doses of ascorbate may be of therapeutic value, emphasize that ascorbate and glutathione have actions in common and that they function together in a physiologically significant antioxidant system.

Animals↗
PubMed1992

The contribution of residue ion pairs to the helical stability of a model peptide.

Comparative CD measurements were made on the model helical peptides acetylYEAAAKEAXAKEAAAKAamide and acetylYEAAAEKAXAKEAAAKAamide in which X represents a nonaromatic nonionic residue. The former peptide contains three potential i, i + 4 complementary ion pairs at neutral pH, while the latter peptide contains one potential complementary and two potential antagonistic i, i + 4 ion pairs. The effect of pH and ionic strength on the mean residue ellipticity of these peptides was measured at 222 nm and 0 degrees C. These measurements were analyzed assuming a common two-state helix/coil transition and only i, i, + 4 ion-pair interactions. The analyses suggest that the central ion pairs do modulate helical content while the peripheral ion pairs do not, presumably due to the location of the peripheral ion pairs in the frayed ends of the helix. The complementary central ion pair stabilizes the helix by about 0.4 kcal/mole and the antagonistic central ion pair destabilizes the helix by about 0.2 kcal/mole.

Amino Acid Sequence↗
PubMed1992

Ambiguous coronary angiography: clinical utility of intravascular ultrasound.

We report the use of intravascular ultrasound (IVUS) in situations where angiography was ambiguous or uncertain in assessing the significance of coronary stenoses. The indications for performing intravascular ultrasound were 1) angiographic findings did not correlate with the clinical presentation (n = 5) and 2) the lesion was not seen well by angiography because of overlapping vessels at the site of suspected stenosis (n = 3). We studied eight lesions in seven patients. Six nonobstructive stenoses on angiography were shown by IVUS to be significant. In two patients, stenoses were thought to be significant on angiography, but, due to overlapping of the vessels, there was doubt regarding the severity of the narrowing. In these two patients, IVUS clearly showed that the lesions were nonobstructive. As seen from the above results, angiography underestimated 6/8 stenoses and overestimated in 2/8 stenoses when compared to IVUS. We conclude that IVUS can be used to clarify ambiguous angiographic findings which can have a major impact on the clinical decision making.

Aged↗
PubMed1992

Intracoronary thrombus: chronic urokinase infusion and evaluation with intravascular ultrasound.

Percutaneous revascularization of coronary arteries with intraluminal thrombi is a clinical problem. We report a patient in whom we administered prolonged infusion of intracoronary urokinase and then assessed the stenosis with intravascular ultrasound before and after atherectomy. We found both angiography and intravascular ultrasound to be misleading in determining the presence of residual thrombus after thrombolysis.

Adult↗