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R L Smith

Publications and source records attributed to R L Smith.

744 records · Page 42Linked to original sources
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Measurement of salicylsalicylic acid and salicylic acid in plasma by high pressure liquid chromatography.

Salicylsalicylic acid (SS) and salicylic acid (SA) both appear in plasma after the oral ingestion of the former. They can be estimated in the presence of each other after extraction into dichloromethane using high pressure liquid chromatography. SS is unstable in plasma, being converted to SA in vitro. Conversion can be prevented by using ethylene diaminetetraacetic (EDTA) as an anticoagulant and carrying out the extraction in the cold. An aliquot of the extract is dried and dissolved in methanol. Weak solutions of SS in methanol are unstable at room temperature. Methanolysis can be prevented by the addition of dilute hydrochloric acid. By adding phenylbutazone to the plasma as an internal standard, variations in extraction and sample application are nullified. Quality control is achieved by concurrent extraction of two different plasma standards containing SS and SA in known amounts. About 40 ng of SS and SA can be detected; reproducibility at 200 ng and above is better than 6.5 percent.

Chromatography, High Pressure Liquid↗
PubMedDate not supplied

Species differences in the metabolic conjugation of clofibric acid and clofibrate in laboratory animals and man.

The urinary metabolites of single doses of clofibric acid (p-chlorophenoxyisobutyric acid), and its ethyl ester, clofibrate, have been investigated in rat, guinea pig, rabbit, dog, cat, ferret, and human volunteers. Human volunteers, rodents, and rabbits given clofibric acid excreted 60-90% of the 14C dose in the urine in 24 hr, and the only metabolite found was the ester glucuronide of clofibric acid, together with small amounts of the unchanged acid. In the dog, cat, and ferret, however, urinary excretion of 14C was much slower (23-39% of dose in 24 hr) and these species all formed the taurine conjugate of clofibric acid, excreted together with the unchanged acid. The ester glucuronide was found in the urine of dog and ferret but not cat. The fate of clofibrate, the ethyl ester of clofibric acid, in rat, guinea pig, rabbit, and man was similar to that of the parent acid. The characterization of the glucuronic acid and taurine conjugates of clofibric acid is described.

Animals↗
PubMedDate not supplied

Central venous catheter infection rates in an acute care hospital.

When questions arose in the spring of 1990 concerning central venous catheter infections at a 414-bed, midwestern hospital, it was found that no hospital-wide prospective study of this problem had ever been completed. A descriptive, prospective study was conducted over 6 months, from October 1990 to April 1991, to determine the rate of infection associated with short-term central venous catheters at the study hospital. Additional research questions sought to examine the influence of certain risk factors on central venous catheter infection rates. Observation of central venous catheter sites was done every other day. Distal catheter segments were cultured by the semi-quantitative roll-plate method and by broth culture. Blood cultures were drawn at the physicians' clinical discretion. Organisms were fully speciated when clinically indicated. The investigators examined 448 catheters in 209 patients. One hundred thirty-nine catheters were not cultured because of random human error or coroner's requirements. In the remaining 309 catheters in 158 patients, a total of 5 clinical line infections was found. The infection rates were 1.6% for catheters, 2.8 infections per 1000 catheter days, and 3.2% per patient. Correlation of infection with risk factors was not possible because of the small number of infections. The clinical line infection rates found in this study compare favorably with other rates reported in the literature. Although the presence of any exceptional problem with central line infections at the hospital was not supported by this study, the number of lines placed during the study emphasizes the importance of high-quality central venous catheter placement and maintenance technique throughout the institution.

Acute Disease↗