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Biomedical subjects

K McCormick

Publications and source records attributed to K McCormick.

At least 73 records · Page 4Linked to original sources
PubMed1989

Valproic acid disposition and protein binding in pregnancy.

Nine epileptic women were followed prospectively through pregnancy on a monthly basis. At each visit, total and free serum valproic acid levels and albumin levels were obtained. Assays were done by gas-liquid chromatography, and free drug was separated by ultrafiltration. Despite an upward dose adjustment in four patients, total valproic acid levels declined as pregnancy proceeded, but free levels did not. Plasma free fractions and clearances increased, but intrinsic clearances, which were adjusted for changes in body weight, remained unchanged.

Adult↗
PubMed1988

Preservation of intermediary metabolism in saponin-permeabilized rat adipocytes.

A unique permeabilized adipocyte model is described in which vigorous intracellular intermediary metabolism is preserved through both the pentose and glycolytic-Krebs pathways following saponin-induced pore formation in plasma membranes. Upon addition of appropriate cofactors, the cells metabolize both glucose and glucose 6-phosphate at rates which are severalfold greater than control (membrane-intact) cells. Saponin is shown to mediate these metabolic effects solely by creating membrane pores through which substrate influx occurs. This cell model provides an unprecedented opportunity to examine intermediary metabolism in situ because it permits the entry into the cytosol of previously restricted substrates, modifiers, and radiolabeled compounds. By circumventing the glucose transporter while, for the most part, preserving plasma membrane integrity, these metabolically active, porous adipocytes may permit the direct exploration of postinsulin receptor glucose metabolism by various hormones or drugs.

Adipose Tissue↗
PubMed1988

Carnitine palmitoyltransferase: effects of diabetes, fasting, and pH on the reaction that generates acyl CoA.

Although carnitine palmitoyltransferase (CPT) has received considerable attention, particularly its regulation by malonyl CoA, most studies have monitored the forward reaction, ie, the formation of acylcarnitine. We examined the opposite or reverse reaction, in which palmitoyl CoA is generated, in osmotically-disrupted rat hepatic mitochondria. Specifically, the effects of pH, fasting, and untreated recent-onset diabetes were investigated. As with the forward (f) reaction, the CPT reverse (r) velocity v pH curve was somewhat parabolic with a pH maximum at approximately 7.2 (except the CPT that was from the diabetic rats). However, as the pH rose, the CPT reverse and forward curves diverged due to a precipitous decline in the forward reaction. This discordance in rates in the alkaline range was apparent in all three groups of CPT but was most prominent in the diabetic preparation (for example, as the pH increased from 7.3 to 8.8, the respective declines in the f and r velocities were 74% and 2%). In addition, under our assay conditions the CPTr from diabetic rats not only had a higher velocity (55.4 +/- 1.4 nmol/min/mg protein) than that from the fed (32.1 +/- 3.1) or fasted (43.1 +/- 3.4) animals, but also the Vmax was found to be twofold greater, even though there was no difference in the Km for palmitoylcarnitine. In summary, diabetes affects the kinetics of the reverse reaction and, regardless of the animal's premortem condition, but more so in the diabetes, this reaction is less attenuated than the forward one as the pH rises.

Acyl Coenzyme A↗
PubMed1988

Fluid homoeostasis during prolonged low-intensity walking on consecutive days.

1. The effect on fluid homoeostasis of walking 37 km on each of 4 consecutive relatively cool days was studied in six male subjects. The daily exercise intensity was consistent and was equivalent to 17(1)% [mean (SE)] of maximum oxygen uptake for these subjects. 2. The diet during the study consisted of a mainly carbohydrate breakfast, consumed immediately before each day's exercise, and unrestricted access to a normal mixed diet after completion of each day's exercise. Water was allowed ad libitum during the walk. Food and fluid intake were recorded. 3. Body weight remained constant over the 4-day walk. The difference between total daily fluid intake and the corresponding 24 h urine output was 1684 (250) ml, 1621 (522) ml, 1107 (252) ml and 1406 (208) ml, respectively, on each of the 4 exercise days. 4. There was a calculated increase of 21.3(6.6)% in plasma volume over the 4-day walk; the largest daily change [11.3(2.9)%] occurred during the walk on day 1. The increase in plasma volume was maintained for at least 4 days after completion of the walk. 5. From day 2, serum sodium concentration tended to increase during the exercise period and fell to the pre-exercise concentration during the overnight rest periods. The concentration of the other measured serum constituents remained relatively constant, and serum osmolality did not alter over the study period.

Blood Proteins↗
PubMed1988

Effects of a non-steroidal anti-inflammatory drug on delayed onset muscle soreness and indices of damage.

Twenty untrained male volunteers were required to run downhill for 45 minutes on a motor driven treadmill to induce muscle soreness. The volunteers took diclofenac or placebo before and for 72 hours after two runs 10 weeks apart, in a randomised double blind crossover design. Subjective soreness was assessed before and at intervals up to 72 hours after each run; venous blood samples, collected at the same time intervals, were used to estimate serum activities of creatine kinase, lactate dehydrogenase and aspartate aminotransferase and serum concentrations of creatinine and urea. Subjective soreness and the biochemical parameters increased after both runs, although the serum enzyme response to the second run was reduced. Diclofenac had no influence on the serum biochemical response to downhill running. Although overall soreness was not affected by diclofenac, individual soreness measurements were reduced by diclofenac at the first period of the study. These results suggest that diclofenac does not influence muscle damage, but may slightly reduce the associated soreness.

Adolescent↗