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Biomedical subjects

R C Rock

Publications and source records attributed to R C Rock.

At least 37 records · Page 2Linked to original sources
PubMed1979

Serum creatine kinase isoenzyme MB activity: evaluation of a kit employing agarose-gel electrophoresis with overlay paper fluorescence scanning.

A commercial kit for determining serum creatine kinase isoenzyme MB activity was evaluated. The kit employed agarose-gel electrophoresis followed by incubation of overlay paper on the agarose and then fluorescnece scanning of the paper. Within-day coefficients of variation ranged from 24.9% for a specimen with no elevation of MB activity of 6.6% for a specimen with moderately elevated MB activity. The kit appeared to demonstrate MB in all sera and showed higher than expected values in recovery studies. The kit performed in a relatively linear fashion from 50 to 500 I.U./l total creatine kinase activity. Hemolysis appeared to lower measured MB. For comparison with another method, specimens were also analyzed by microcolumn chromatography, which was found to incompletely separate isoenzymes. The kit produced lower values than microchromatography for specimens with low MB activities and higher values for specimens with elevated MB activities. Patients without corroborative evidence of myocardial injury showed a somewhat hyperbolic relationship between per cent MB and total creatine kinase activity, but MB activity was generally 4 I.U./l or less. Although the kit had serious laboratory shortcomings, it may be as clinically useful as other methodologies.

Chromatography, Ion Exchange↗
PubMed1979

Lipoprotein X and alkaline phosphatase as indicators of cholestasis.

Lipoprotein X is considered to be an indicator of cholestasis, but its clinical usefulness is unclear owing to different methods of measurement in use and varying definitions of cholestasis. We investigated the reliability of the qualitative determination of lipoprotein X in predicting cholestasis, defined here as the presence of stainable bile in tissue sections. Liver tissue and serum were collected from 42 patients. Patients were divided into those who did and those who did not have stainable bile in tissue sections. Lipoprotein X was demonstrated by electrophoresis and polyanion precipitation. Lipoprotein X in serum correlated with the presence of stainable bile (p = 0.0006). A normal range of alkaline phosphatase values correlated with the absence (p = 0.04), but elevated values did not correlate with the presence of stainable bile. In patients known to have elevated alkaline phosphatase, the presence of lipoprotein X still correlated with the presence of bile (p = 0.008). We conclude that lipoprotein X is a reliable indicator of cholestasis and that it is more useful than alkaline phosphatase in this application.

Alkaline Phosphatase↗
PubMed1977

Creatine kinase and lactate dehydrogenase in type 2 glycogenosis (Pompe disease).

At least three varieties of type 2 glycogenosis (Pompe disease) have been described, the most severe of which is an infantile form. The relationship between clinical manifestations, glycogen accumulation, and tissue damage has not been established. Serum levels of creatine kinase (CK [EC 2.7.3.2 adenosine triphosphate:creatine phosphotransferase]) lactate dehydrogenase (LDH [EC 1.1.1.27 L-lactate:NAD oxidoreductase]) and their isoenzyme fractions were used to identify and monitor myocardial damage in this study of an infant with type 2 glycogenosis diagnosed by light microscopy and tissue enzyme assay.

Creatine Kinase↗
PubMed1977

A semi-automated fluorometric method for total estrogens in pregnancy urine.

We report a continuous-flow fluorometric method for total urinary estrogens that involves the Kober reaction, with extraction of the reaction product into dichloroethane containing trichloroacetic acid as described by Hahnel and Jones [Clin. Chim. Acta 16, 185 (1967)]. The dichloroethane extraction gives greater stability to the Kober color and sharper separation of aqueous and organic phases. The analytical system is adjusted to give maximum response to estriol 16alpha,beta-D-glucuronide, the principal estrogen conjugate in urine from late pregnancy, when calibrated with estriol standards. An initial 20-fold dilution of the sample with water increased analytical recovery of estriol conjugates from urine while maintaining adequate fluorescent response. Glucose interference was reduced by dilution and eliminated by treatment with sodium borohydride. Urinary protein up to 20 g/liter did not interfere. Total estriol, as determined by gas-liquid chromatography, comprises about 70% of total urinary estrogens in late pregnancy as measured by our continuous-flow fluorometric method. A reference range is presented based on 209 randomly collected urine specimens in which total urinary estrogens are expressed as a ratio to creatinine.

Chromatography, Gas↗