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Biomedical subjects

R Zimmer

Publications and source records attributed to R Zimmer.

At least 91 records · Page 5Linked to original sources
PubMed1975

Rates of lactic acid permeation and utilization in the isolated dog brain.

The rate of lactic acid (LA) permeation from brain tissue to venous blood and utilization in brain tissue was investigated in 13 isolated dog brains before and after an ischemic period of 3 min. LA concentration in the brain, cerebral blood flow, as well as the arteriovenous differneces of LA, glucose, and O2 were determined. LA concentration in cerebral tissue increased from a control value of 254 +/- 42 to 1,606 +/- 177 mumol/100 g brain tissue in the 2nd min after ischemia (mean values +/- SE). Before ischemia no release of LA was found, whereas in the 2nd min after ischemia LA permeation rate had increased to 25.1 +/- 8.5 mumol/100 g brain tissue per minute (P less than 0.005). Up to the 4th min after ischemia no net LA utilization was observed. Thereafter LA utilization increased rapidly and exceeded the LA permeation rate by a ratio of maximally 10:1 between the 12th and 21st min after ischemia. The O2 equivalent of the cerebral metabolic rate for lactate maximally amounted to 2.82 +/- 0.42 mumol-min-1-g-1 or 181 +/- 28%. LA output may be limited by passage of LA across the brain cell and the blood-brain barrier.

Animals↗
PubMed1974

[Medical control].

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Allied Health Personnel↗
PubMedDate not supplied

Pharmacokinetics and tolerance of romazarit after oral administration of ascending single doses to healthy human volunteers.

Forty-four healthy male volunteers participated in an investigation of the pharmacokinetics and tolerance of single oral doses of romazarit, a potential disease-modifying antirheumatic drug. The study design involved single oral doses in ascending sequence from 40 to 1500 mg. At each dosage 9 volunteers were studied, of whom 6 received romazarit and 3 received placebo capsules in a double-blind manner. Tolerance was assessed before and after each of the 57 romazarit and 27 placebo doses. Plasma and urinary concentrations of romazarit were measured by HPLC with UV detection. Model-independent pharmacokinetic analyses showed that romazarit was rapidly and extensively absorbed in a dose-proportional manner. Urinary recovery of drug related material was about 70% of the dose and almost all in the form of labile metabolites (probably acyl glucuronides). Clearance was faster (greater than 3 l/h) at doses below 700 mg, than in the range 700-1500 mg (1.7 l/h). It is suggested that two or more clearance mechanisms are present. One of these mechanisms is saturable and may involve a reversible ester glucuronide formation coupled with saturable tubular secretion of glucuronides. Romazarit was well tolerated in these healthy volunteers. There were two reports of stomach pain, one associated with vomiting. Changes in laboratory safety test results and in measurements of vital signs were similar in frequency and magnitude after romazarit and after placebo doses.

Administration, Oral↗