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Biomedical subjects

S A Kline

Publications and source records attributed to S A Kline.

35 records · Page 2Linked to original sources
PubMed1982

Mutagenicity of chloroalkene epoxides in bacterial systems.

6 alpha-chloroepoxides have been tested for in vitro activity in a variety of systems. The epoxides were cis- and trans-1-chloropropene oxide, cis- and trans-1,3-dichloropropene oxide, trichloroethylene oxide and tetrachloroethylene oxide. The epoxides were assayed for mutagenicity in the absence of metabolic activation in S. typhimurium TA1535 and E. coli WP2 uvrA and for preferential inhibition of growth of DNA-repair-deficient E. coli. All 6 epoxides possessed DNA-modifying activity as evidenced by their ability to preferentially inhibit DNA polymerase-deficient E. coli. All of the test chemicals except trichloroethylene oxide were mutagenic for S. typhimurium and all except trichloroethylene oxide and tetrachloroethylene oxide were mutagenic for E. coli Wp2 uvrA. Cis- and trans-1,3-dichloropropene oxide were the most potent mutagens and DNA modifiers. For all cases, the cis isomers were more active than the corresponding trans isomers. alpha-Chloroepoxides are considered likely to be the active intermediates of the carcinogenic parent halo-olefins. These mutagenicity studies are considered relevant in assessing the carcinogenicity of the parent hydrocarbons.

DNA Polymerase I↗
PubMed1979

Perioperative myocardial infarction associated with coronary artery bypass graft surgery: improved sensitivity in the diagnosis within 6 hours after operation with 99mTc-glucoheptonate myocardial imaging and myocardial-specific isoenzymes.

The present study was performed to evaluate scintigraphic imaging with technetium 99m-labeled glucoheptonate and serum enzyme levels of creatine phosphokinase isoenzyme (MB-CPK) in the early diagnosis of perioperative acute myocardial infarction associated with saphenous vein bypass graft operations. Myocardial imaging was done in 27 patients (50% of whom were considered high-risk) before operation and again 5 hours after operation. Four of these patients (15%) had both electrocardiographic and serum MB-CPK evidence of acute myocardial infarction, and all 4 had developed positive postoperative scintigrams. Four other patients had only elevated serum MB-CPK, and scintigrams became positive after operation in 3 of them. In addition, serum MB-CPK 6 hours after operation was 83 +/- 21 mIU/ml (mean +/- standard error of the mean) in patients with positive postoperative scans compared with 24 +/- 5 mIU/ml in those patients with negative postoperative scintigrams (p less than 0.001). Myocardial imaging with 99mTc-glucoheptonate in the perioperative period is rapid, safe, and atraumatic. Furthermore, our results suggest that it is a sensitive method for the early diagnosis of perioperative acute myocardial infarction, and, when imaging is combined with serum MB-CPK isoenzyme analysis, the reliability of the diagnosis of acute myocardial infarction is enhanced even further. Only 1 of the patients who showed perioperative myocardial damage had acute hemodynamic compromise or obvious impairment of recovery in the immediate postoperative period, and the 30-day mortality of the total group was 4% (1 of 27).

Acute Disease↗
PubMed1979

The limits of Munchausen's syndrome.

The authors review the literature on Munchausen's syndrome and speculate about possible underlying psychological mechanisms. The proposed DSM III classification of factitious illnesses suggests a continuum from hysteria on one end of the spectrum to malingering on the other. Two case studies are presented which represent variants of this syndrome. Both patients were given a sodium amytal interview, a procedure not previously reported in the Munchausen's literature. The procedure was helpful in eliciting a more accurate history and a clearer sense of the underlying dynamics. Some suggestions for further research are made.

Adult↗
PubMed1978

Early quantification of experimental myocardial infarction with technetium-99m glucoheptonate: scintigraphic and anatomic studies.

Recent advances in understanding of the pathophysiology of myocardial necrosis indicate the need for a noninvasive method that will allow detection and quantification of infarcts in the first few hours after the onset of infarction. Myocardial infarct scintigraphy using technetium-99m glucoheptonate is capable of detecting infarction in dogs and man within 4 to 6 hours of onset. Studies were performed in 45 dogs with acute myocardial infarction: 28 with with an anterior infarct, 5 with an inferior infarct, 6 with an anterior infarct studied after infusion of mannitol and 6 with ligation of the left anterior descending coronary coronary artery and reperfusion of the ischemic area. The dogs were given 20 m Ci of technetium-99m glucoheptonate 1 hour after coronary occlusion, subjected to imaging 5 to 9 hours later and then killed. The experiments revealed that (1) scintigraphic infarct size correlated with infarct weight for anterior (r = 0.85) and inferior (r = 0.88) infarcts; (2) technetium-99m glucoheptonate also concentrated in a rim of myocardium around the infarct that probably represented the ischemic zone; and (3) technetium-99m glucoheptonate uptake by infarcted myocardium could be greatly increased with mannitol and reperfusion.

Animals↗
PubMed1977

Left ventricular performance and graft patency after coronary artery-saphenous vein bypass surgery: early and late follow-up.

Left ventircular performance and graft patency were studied postoperatively at 2 weeks in 19 patients, and at 9 months in 15 patients. At early follow-up, left ventricular ejection fraction and mean rate of circumferential shortening were unchanged for the group as a whole, but were slightly improved in patients who had had a moderately abnormal preoperative ejection fraction of 0.30 to 0.60. At late follow-up, 10 of 14 patients had occluded at least one graft or the proximal segment of the grafted coronary artery and had an associated decrease in ventricular function. The risk of graft occlusion was greater if the preoperative ejection fraction was decreased; seven of 10 patients with a preoperative EF of less than 0.60 suffered one or more graft occlusions, but only three of 16 patients with a preoperative EF greater than 0.60 had a postoperative graft occlusion (p is less than 0.05). The results suggest that bypass graft surgery is not generally indicated as a measure to improve ventricular function in patients with ischemic heart disease.

Angina Pectoris↗
PubMed1977

Effect of additional valve lesions on left ventricular ejection time in aortic stenosis.

Rate-corrected left ventricular ejection time was measured from the aortic pressure tracings of 171 catheterised patients with aortic valve area less than or equal to 1.2 cm2. In 50 patients with pure aortic stenosis, left ventricular ejection time in increased with decreasing valve area and was significantly higher (468 +/- 5 ms, mean +/- SEM) than in 13 normal subjects (435 +/- 5 ms). Additional aortic regurgitation in 72 patients further increased the left ventricular ejection time to 484 +/- 4 ms. Significant mitral stenosis (mitral valve are less than or equal to 1.2 cm2) in 6 patients with aortic stenosis and 33 patients with aortic stenosis and regurgitation reduced the left ventricular ejection time to normal. Similarly, severe mitral regurgitation in 3 patients with aortic stenosis and regurgitation reduced left ventricular ejection time to normal, though slight or moderate mitral regurgitation in 4 of these patients did not. These data show that the prolonged left ventricular ejection time in aortic valve disease may be restored to normal in the presence of coexisting significant mitral disease.

Aortic Valve Insufficiency↗
PubMed1975

Disulfiram implants in the treatment of alcoholism some mechanisms of action.

For nearly 20 years, disulfiram implanted subcutaneously, has been used in alcoholics who have failed to respond to other treatment. Significantly positive results have been reported in a large number of cases. Despite this extensive use, many questions remain as to how these effects are exerted. As the reaction to alcohol following disulfiram implantation occurs less frequently and in lower intensity than following oral ingestion, psychological mechanisms probably play a vital role. Based in part on out own recent series of cases, the following explanations are offered regarding the possible mechanisms of action: (1) high motivation to stop drinking is manifested by agreeing to the precedure and reinforced by the procedure; (2) palpable presence of hte drug in the site of implantation; (3) generally sufficient reactivity of the agent to indicate activity to the patient;(4) in obsessional patients there is a removal of the fear of resumption of drinking for an extended period of time. For the more sociopathic patients the implant appears to provide a more structured ego boundary to allow the patient to change.

Adult↗
PubMedDate not supplied

Reaction of (E,E)-muconaldehyde and its aldehydic metabolites, (E,E)-6-oxohexadienoic acid and (E,E)-6-hydroxyhexa-2,4-dienal, with glutathione.

(E,E)-Muconaldehyde (muconaldehyde) has been identified as a hematotoxic metabolite of benzene in vitro. It is metabolized in mouse liver cytosol to oxidized and reduced derivatives including the alpha, beta-unsaturated aldehydes (E,E)-6-oxohexadienoic acid and (E,E)-6-hydroxy-2,4-hexadienal. In this study we have synthesized the aldehydic metabolites of muconaldehyde. The reaction of glutathione with muconaldehyde and its aldehyde metabolites was investigated. Reactions were bimolecular and stoichiometric in aldehyde and glutathione in the initial phases. Second-order rate constants were determined, and the rates were in the order muconaldehyde > (E,E)-6-hydroxy-2,4-hexadienal > (E,E)-6-oxohexadienoic acid. Further investigation of the reaction of muconaldehyde with glutathione showed that the bimolecular reaction is reversible but the initial product decomposed irreversibly to two or more products, one of which had a red-shifted UV spectrum. Rate constants for these subsequent reactions were determined. The results are discussed in terms of the toxicity of muconaldehyde at tissues distal from the liver, where it is believed to be formed from the metabolism of benzene.

Aldehydes↗
PubMedDate not supplied

An angiographic assessment of left ventricular function in isolated mitral valvular prolapse.

Angiographic studies demonstrating alterations in left ventricular contraction have been cited as evidence that isolated mitral valve prolapse (MVP) may be associated with a cardiomyopathy. We studied 17 patients with isolated MVP undergoing cardiac catheterization who had chest pain, palpitations, and/or a murmur of mitral regurgitation. Eleven of 13 patients (85%) with no or mild (Grade 1+) mitral regurgitation had normal left ventricular hemodynamic measurements, while three of four patients (75%) with moderate or marked (Grades 2+-4+) regurgitation had abnormal left ventricular hemodynamic measurements. An increased mean rate of circumferential fiber shortening (greater than 1.9 circumferences/sec) was observed in nine of 13 patients (70%). Systolic ventricular wall motion was analyzed from left ventriculograms by methods which quantitate percent shortening of ventricular areas, transverse chords, and radial axes. Marked variations in the number and location of alterations in ventricular contraction were obtained by the different methods used to analyze the ventriculograms, with segments of hypokinesis being detected in from 0-14 patients studied, depending upon the method used. Localization of alterations in contraction predominantly in the basal and mid-segments of the left ventricular and the association of hemodynamic abnormalities with mitral regurgitation suggest that changes in ventricular contraction are primarily related to an alteration of mitral valve function in this condition.

Adult↗
PubMedDate not supplied

The relationship of depression to survival in chronic renal failure.

The authors examine the relationship between psychosocial factors and factors and survival of patients with chronic renal failure, while considering simultaneously the influence of parameters of physiologic functioning. Psychosocial and physiologic variables selected for discriminant analysis were extracted from data on 285 home-dialysis patients in Ontario, Canada. This analytical procedure defined which variables best discriminated between the survivor and nonsurvivor groups. The findings suggest that demographic and psychosocial factors may be more important than physiologic variables in determination of survival on home dialysis. The severity and type of depression is of particular importance to outcome.

Adjustment Disorders↗