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Biomedical subjects

E C Clark

Publications and source records attributed to E C Clark.

35 records · Page 2Linked to original sources
PubMed1990

Role of ammonia in tubulointerstitial injury.

Accelerated rates of ammonia production by the renal proximal tubule constitute an important adaptation to chronic renal injury. Although serving to maintain net acid excretion, this augmented production of ammonia per nephron results in increased renal cortical levels of ammonia and contributes to progressive renal injury. Ammonia fosters progressive injury via its ability to modify the third component of complement and initiate alternative complement pathway activity. This interaction of ammonia with complement incites inflammation in models of nonimmune chronic renal disease in the rat and may contribute to tissue injury in pyelonephritis involving urease-positive organisms. The long recognized in vivo association between increased renal ammoniagenesis, renal growth, and progressive injury in several models of renal disease has been advanced by the recent demonstration of ammonia as a direct stimulus to growth of renal tubular epithelium in culture. Additionally, evidence from studies of acute ischemic renal injury suggests a contributory role for ammonia in mediating tissue injury in this model. Elevated renal levels of ammonia, therefore, contribute to tubulointerstitial injury primarily through the proinflammatory and growth-promoting properties of ammonia.

Acute Disease↗
PubMed1988

Evaluation of a portable measure of expired-air carbon monoxide.

There are a variety of independent methods of estimating smoking status; measurement of expired air carbon monoxide has proven to be reliable and convenient. This article describes a new, inexpensive, portable analyzer for measuring expired-air carbon monoxide --the Bedfont EC50. We have compared this analyzer with the standard instrument for measuring expired-air carbon monoxide in 138 normal subjects and found good correlation and agreement. The Bedfont was demonstrated to be better at identifying smoking status, and the relevance of this finding for classification of smokers and nonsmokers by fixed-threshold carbon monoxide levels is discussed. The features of the Bedfont EC50 are particularly appealing for field and clinical use.

Adult↗
PubMed1979

Intraoperative hemodialysis during cardiopulmonary bypass in chronic renal failure.

This report describes the features and the course of a patient on maintenance hemodialysis in whom infective endocarditis of the aortic valve ensued. The subsequent development of intractable congestive heart failure necessitated aortic valve replacement. Use of intraoperative hemodialysis, facilitating the intraoperative and postoperative management of the patient, is described. Following valve replacement the patient did well with no evidence of congestive heart failure.

Aortic Valve↗
PubMed1977

Unreliable drug histories, analgesics, and changes in renal function.

One hundred and nine outpatients were questioned on their use of analgesics and asked to provide urine and blood samples. Forty-one per cent said they used analgesics daily and 54% said they had ingested analgesics during the 3 days before questioning. The analgesics used were mainly aspirin or paracetamol, alone or in combination. Five (42%) of the patients who denied the use of analgesics, and 10 (29%) of those who denied intake during the preceding week, had detectable amounts of paracetamol or aspirin in their urine. Mean serum urea, although still within the normal range, increased with increasing use of analgesics. The mean serum urea of patients who used aspirin and paracetamol in combination was significantly higher than that of those who used either of the drugs alone. The findings suggest that one should not rely heavily on the history of analgesic use, and that by replacing phenacetin with paracetamol one might not have achieved much as far as renal function is concerned.

Acetaminophen↗
PubMed1977

The on-off effect in Parkinson's disease treated with levodopa with remarks concerning the effect of sleep.

The "On-Off Effect" in levodopa treated Parkinson's disease began in a few patients during the first year of treatment. The number of patients suffering from this phenomenon increased rapidly the first three or four years with some continuing increase throughout the six years of the study. Even those whose disease had worsened would become even more incapacitated during parts of each day. One group of patients experienced their initial "On" effect upon arising at their usual hour of awakening. This would last for 1 to 3 hours and was their best time of day.

Aged↗
PubMed1975

Thin-layer chromatographic method for determining carbamazepine and two of its metabolites in serum.

A sensitive and highly specific thin-layer chromatographic method for determining simulataneously serum levels of carbamazepine and two of its major metabolites, carbamazepine-10 11-epoxide and 10, 11-dihydroxycarbamazepine, is presented. Serum (1 mug) was spotted directly onto the thin-layer plate and, after irrigation, the separated spots were converted into fluorescing compounds by exposing the plates to hydrogen chloride gas for 5 min and then to strong ultraviolet radiation from a mercury lamp for 20 min. The fluorescence was measured quantitatively using a spectrofluorimeter equipped with a thin-layer chromatogram scanning attachment. Two microlitres of serum are sufficient for a duplicate determination.

Carbamazepine↗
PubMed1975

GLC determination of phendimetrazine in serum.

A sensitive, specific, and quantitative GLC method for the determination of phendimetrazine in serum is described. The procedure involves the addition of an internal standard to serum samples, followed by extraction at pH 13 into toluene. The extracted bases are back-extracted into 1 ml of 4 M hydrochloric acid and again into 100 mu1 of chloroform after making the 4 M hydrochloric acid extract basic with 1.5 ml of 4 M sodium hydroxide. The sensitivity of the method is such that 25 ng of material can be detected in 5 ml of serum.

Chromatography, Gas↗
PubMed1975

Human cadaver kidney preservation using hypothermic hyperosmolar, intracellular washout solution.

The utilization of a hypothermic, hyperosmolar, intracellular washout solution for human kidney preservation was shown to be successful in 18 kidneys obtained from 9 heart beating cadavers. The ischemic interval ranged from 2 hrs and 57 mins to 39 hrs and 48 mins. All 18 kidneys functioned within 3 hrs of revascularization. Acute tubular necrosis with oliguria was noted in 4 of 6 patients with ischemic intervals longer than 20 hrs but not in the 12 patients obtaining kidneys preserved for 19 hrs or less. All patients with acute tubular necrosis required hemodialysis for one to 16 days post-transplantation with eventual recovery.

Adolescent↗