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Biomedical subjects

A Jain

Publications and source records attributed to A Jain.

At least 379 records · Page 21Linked to original sources
PubMed1990

Assessing suicide risk in stroke patients: review of two cases.

Poststroke depression can be accompanied by suicidal ideation, yet reports of suicide among stroke patients are rare. When untreated, depression can become prolonged and severe. Risk factors for suicide include depression, severe insomnia, chronic illness, and organic brain syndrome. Early clinical assessment of suicide risk factors is essential in the rehabilitation setting. Two patients who developed mood disturbances in the acute poststroke period and eventually committed suicide are presented. Neither patient openly expressed suicidal thoughts to staff or family members. Retrospective analysis of medical records was compared to established suicide risk factors reported in the medical literature. Indirect verbal cues and nonverbal behavior patterns indicating potential suicide risk may have been present. Strategies for evaluation and management of suicidal behavior are discussed. These cases emphasize the need for early assessment of suicide risk by the entire rehabilitation team.

Aged↗
PubMed1990

Coronary artery fistula: an abnormality affecting all age groups.

A coronary artery fistula is an abnormal communication between a coronary artery and a cardiac chamber, great vessel, or other vascular structure. It is an infrequent but potentially important abnormality that can affect any age group. Most are congenital in origin, although other etiologies, in particular trauma, have been identified. Many are small and found incidentally during coronary arteriography, while others are identified as the cause of a continuous murmur, myocardial ischemia, congestive heart failure, or, rarely, bacterial endocarditis. The diagnosis should be considered in any patient presenting with a continuous murmur or in the setting of congestive heart failure, myocardial ischemia, or bacterial endocarditis without an obvious etiology. The pathophysiologic mechanisms resulting in symptoms include cardiac volume overload due to the shunting of blood and reduction of the myocardial blood supply due to "coronary steal." The diagnosis of coronary artery fistula may be suggested by the finding of a continuous murmur in a precordial location, which is atypical for patent ductus arteriosus. Two-dimensional echocardiography may demonstrate dilated coronary arteries, and pulse-wave and color-flow Doppler examinations can display turbulent flow in the suspected fistula and its receiving chamber or vessel. Angiography is generally needed to confirm the diagnosis and elucidate anatomic detail. The natural history of coronary artery fistula is variable, with long periods of stability in some patients and gradual progression of symptoms in others. Small fistulas detected incidentally at the time of angiography do not require immediate surgical correction, but careful follow-up is indicated because the potential for enlargement with physiologically important shunting exists and cannot readily be predicted. Spontaneous closure is uncommon. Surgical repair of the fistula is recommended for symptomatic patients and for some without symptoms because a quantitatively small shunt does not predict freedom from future symptoms or complications. Those selected for medical management must be followed closely.

Adolescent↗
PubMed1989

FK 506 for liver, kidney, and pancreas transplantation.

FK 506 was given for immunosuppression in 14 liver recipients. The drug was used in the first 10 cases because the recipients under conventional immunosuppression had rejection, nephrotoxicity, or both. This salvage therapy was successful in 7 of the 10 attempts. 2 of the 10 patients in the original salvage group as well as 4 new patients underwent fresh orthotopic liver transplantation under FK 506 plus low-dose steroids from the outset. None of these 6 patients had rejection although 1 with preexisting cor pulmonale and coronary atherosclerosis died of a myocardial infarction. In addition, 2 of the 14 liver recipients were given cadaveric kidneys, either from the same donor or from a different donor, and a third was given a pancreas as well as a kidney from the liver donor. There were no rejections of the kidney and pancreas grafts, and serious side-effects were not encountered.

Administration, Oral↗
PubMed1989

Limitations of the metabolic rate meter for measuring oxygen consumption and cardiac output.

Over the past few years, a metabolic rate meter has been introduced for easy measurement of oxygen consumption. However, its accuracy is unproved. In 40 patients (26 men, 14 women, ages 34 to 73 years), cardiac output was measured simultaneously by thermodilution and the Fick method using the metabolic rate meter to quantitate oxygen consumption. In comparison with thermodilution, the results using the Fick method were low (5.26 +/- 1.18 vs 4.14 +/- 0.99 liters/min, respectively, p less than 0.01). In 18 patients cardiac output also was measured by the Fick method using a Douglas bag to quantitate oxygen consumption. In these patients, oxygen consumption measured with the metabolic rate meter was lower than that obtained using the Douglas bag (168 +/- 25 vs 216 +/- 42 ml/min, respectively, p less than 0.01). With the Douglas bag, the Fick and thermodilution cardiac output measurements were similar (4.68 +/- 1.08 vs 4.87 +/- 0.86 liters/min, respectively, difference not significant), and they differed by less than or equal to 10% in 15 patients. In contrast, with the metabolic rate meter, the results of thermodilution were higher than those with the Fick method (4.84 +/- 0.95 vs 3.60 +/- 0.71 liters/min, respectively, p less than 0.01), and differed by less than or equal to 10% in only 1 patient (p less than 0.01). Thus, the values for oxygen consumption and cardiac output obtained with the metabolic rate meter are lower than actual values. This device is less accurate than the Douglas bag.

Adult↗
PubMed1989

Intracoronary electrocardiogram during torsade des pointes secondary to intracoronary papaverine.

Papaverine, a potent coronary vasodilator, is now commonly used to measure coronary reserve. We recorded intracoronary electrogram in a patient who developed Torsade des pointes after 10 mg of papaverine. This was associated with marked prolongation of the QT interval. The ventricular tachycardia self-terminated with shortening of the QT interval. We believe that although papaverine is a good agent because of its short duration of action, it must be used cautiously because of its effects on repolarization, which can result in arrhythmias.

Electrocardiography↗
PubMed1989

Studies on activation and levels of haemolytic complement of buffalo (Bubalus bubalis). 1. Classical complement pathway.

Optimum conditions for haemolytic complement (HC) assay in buffalo serum were standardized. In all, 11 indicator systems of red blood cells (RBC) and haemolysins were investigated. Maximum HC CH50 titre was obtained with rabbit RBC sensitized with goat haemolysin. The effect of pH, Ca2+ and Mg2+ concentration, ionic strength, time and temperature were studied. Of all the variables, ionic strength influenced the HC activity most significantly. The standard system for titrating the HC consisted of rabbit RBC sensitized with goat haemolysin, sucrose-veronal buffer with pH 7.5, ionic strength 0.023 M and Ca2+ and Mg2+ concentrations 6 x 10(-4) and 2 x 10(-3) M, respectively. Incubation at 37 degrees C for 2 h gave highest haemolytic activity. With this protocol 5-7-fold higher HC activity was recorded than with prestandardized conditions. Levels of HC were determined in the sera of 98 buffaloes aged from 1 month to 12 years. The lowest mean CH50 units of 401 +/- 0.35 per ml were recorded in buffalo calves below 3 months of age. The mean HC levels increased with age, reaching peak values of 2349 +/- 62.25 CH50 units/ml in 2-3-year-old buffalo. Animals in the age group 5-12 years had significantly decreased (P less than 0.05) mean HC levels of 1545 +/- 68.94.

Animals↗
PubMed1989

Glutathione metabolism in the lung: inhibition of its synthesis leads to lamellar body and mitochondrial defects.

Mice treated with buthionine sulfoximine, an inhibitor of glutathione synthesis, showed striking alterations of morphology of lung type 2 cell lamellar bodies (swelling and disintegration) and mitochondria (degeneration) and of lung capillary endothelial cells (mitochondrial swelling). These effects probably may be ascribed to glutathione deficiency; administration of glutathione monoester protects against them. Measurements of arteriovenous plasma glutathione levels across the lung indicate that the net uptake of glutathione by this organ is substantial. Thus, glutathione exported from the liver to the blood plasma is utilized by the lung which, like the liver, kidney, and lymphocytes (and unlike skeletal muscle), exhibits a high overall rate of glutathione turnover. Intraperitoneal injection of glutathione into buthionine sulfoximine-treated mice leads to very high levels of plasma glutathione without significant increase in the glutathione levels of liver, lung, and lymphocytes; on the other hand, administration of glutathione monoester leads to markedly increased tissue and mitochondrial levels of glutathione. Administration of glutathione monoester (in contrast to glutathione) to control mice also increases mitochondrial glutathione levels. The findings indicate that glutathione is required for mitochondrial integrity and that it probably also functions in the processing and storage of surfactant in lamellar bodies. The morphological changes observed after treatment with buthionine sulfoximine and their prevention by glutathione monoester as well as findings on glutathione metabolism indicate that this tripeptide plays an important role in the lung. The previously observed failure of buthionine sulfoximine-treated mice to gain weight is mainly due to glutathione deficiency in the intestinal mucosa.

Animals↗
PubMed1989

Glutathione ester prevents buthionine sulfoximine-induced cataracts and lens epithelial cell damage.

Treatment of newborn rats and mice with buthionine sulfoximine, an inhibitor of glutathione synthesis, leads to development of cataracts, which are not prevented by treatment with glutathione, but they are prevented by treatment with glutathione monoester. Cataracts are associated with glutathione deficiency in the lens epithelium, which undergoes severe degeneration. The findings indicate that glutathione normally functions in the protection of the lens and lens epithelium against oxidative injury, suggesting that procedures that increase lens glutathione levels might be useful for prevention of other types of cataracts. Relatively low doses of buthionine sulfoximine produce cataracts in newborn animals, and treatment of pregnant mice with buthionine sulfoximine during the last part of gestation leads to cataract formation in the offspring. The high sensitivity of the developing lens to the effects of glutathione deficiency suggests that this tissue may be a useful model for studies on glutathione function.

Animals↗
PubMed1988

Dissociation of fibrinogen and fibronectin binding from transglutaminase-mediated cross-linking at the hepatocyte surface.

The interaction of fibrinogen and fibronectin with hepatocytes has been dissociated into distinct binding and cross-linking steps. Binding and cross-linking of 125I-labeled ligands were both decreased by transglutaminase inhibitors, but not by heparin or hirudin. Transglutaminase activity was manifest by Ca2+-dependent incorporation of [14C]putrescine into cells. Preferential cross-linking of fibrinogen A alpha over gamma chains, and lack of inhibition by heparin or hirudin indicates the involvement of tissue transglutaminase, and not Factor XIIIa. Hepatic transglutaminase activity, as well as binding and cross-linking of fibrinogen and fibronectin, were maximally supported by Ca2+, partially supported by Mn2+ and Sr2+, and markedly decreased by Mg2+ and Ba2+. In contrast, Co2+ supported binding but not cross-linking or transglutaminase activity, indicating that binding and cross-linking are dissociable events. This conclusion was corroborated by the finding that fibrinogen fragments D95 and D78 both inhibited Ca2+-dependent fibrinogen binding without being cross-linked themselves. Ligand binding in the presence of either cation was localized to the cell surface as evidenced by its trypsin sensitivity. Thus, fibrinogen and fibronectin binding to hepatocytes is independent of transglutaminase activity, whereas cross-linking of these adhesive macromolecules requires an enzymatically active cellular transglutaminase. In addition, fibrinogen binding appears to be mediated by molecular determinants present in fragment D78.

Animals↗