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Biomedical subjects

K Franke

Publications and source records attributed to K Franke.

At least 19 recordsLinked to original sources

[The results of overloading of the lower extremity during sports (author's transl)].

Nowadays an increasing number of persons have to interrupt their training in competitive or recreational sports because of injuries resulting from overloading of the musculoskeletal system. At least 60% of all athletes who consult a department of traumatology do so because of recurrent micro-trauma. Sixty to eighty percent of all sports injuries and sequelae of overloading are located in the lower limb. The typical results of overloading of the musculoskeletal system during sports are: Inflammation of tendinous insertions, myopathies, peritendinitis, stress fracture, destruction of hyaline cartilage. The commonest of these are insertion tendinitis and destruction of cartilage. This reflects the disproportion between the ultimate strength of the connective tissues, which varies between individuals, and the loads actually imposed during physical training. In the last 7 years (1971-77) we have operated on 1278 knee joints, 63% of which had suffered damage to the cartilage. The etiology, prophylaxis, and medical and surgical treatment of chondropathies are therefore discussed in detail. Careful coordination of the various rehabilitation measures is especially important if a satisfactory therapeutic result is to be achieved.

Athletic Injuries

[The structure of the round window membrane studied by thin section.- freeze-fracture- and scanning electron microscopic technique (author's transl)].

In thin sections of the round window membrane of chinchilla there were found tight junctions between the cells of the outer and of the inner cell layer as well. Their structure was demonstrated in freeze-fracture replica, and in the scanning electron microscope both faces of the membrane appeared uninterrupted. The tight junctions between the mucosal cells constantly became visible and are considered impermeable; however, the junctions connecting the mesothelial cells, which face the perilymph, demonstrated high susceptibility against differences in preparation and were structurally different.

Animals

Freeze fracture aspects of the spiral limbus.

Replicas of the freeze fractured spiral limbus are studied in chinchillas. Zonulae occludentes are demonstrated between the interdental cells and the inner sulcus cells; gap junctions are described connecting interdental cells and inner sulcus cells to one another and they are found between the perilymphatic cells in the spiral limbus.

Animals

Analysis of lorazepam and its glucuronide metabolite by electron-capture gas--liquid chromatography. Use in pharmacokinetic studies of lorazepam.

This paper describes a rapid and sensitive method for analysis of lorazepam and its glucuronide metabolite in plasma and urine following therapeutic doses of lorazepam in humans. After addition of the structurally related benzodiazepine derivative, oxazepam, as the internal standard, 1-ml samples of plasma or urine are extracted twice at neutral pH with benzene (containing 1.5% isoamyl alcohol). The combined extracts are evaporated to dryness, reconstituted, and subjected to gas chromatographic analysis using a 3% OV-17 column and an electron-capture detector. Lorazepam glucuronide in urine is similarly analyzed following enzymatic cleavage with Glusulase. The sensitivity limits are 1--3 ng of analyzed following enzymatic cleavage with Glusulase. The sensitivity limits are 1--3 ng of lorazepam per ml of original sample, and the variability of identical samples is 5% or less. The applicability of the method to pharmacokinetic studies of lorazepam is demonstrated.

Administration, Oral

Impairment of antipyrine clearance in humans by propranolol.

The effect of propranolol on antipyrine clearance in humans was evaluated in six healthy volunteers who received single 1.4 to 1.5 g doses of intravenous antipyrine on two occasions. The first (control) antipyrine trial was without concurrent drug administration; the second trial was done during treatment with therapeutic doses of propranolol (40 mg every 4 to 6 hours). Antipyrine elimination half-life (t1/2), volume of distribution (Vd), and total clearance were determined after each trial. In all subjects isoproterenol sensitivity decreased markedly during propranolol treatment, indicating a high degree of beta blockade produced by the drug. Mean antipyrine t1/2 during the propranolol treatment period was significantly prolonged, and total clearance significantly reduced, over the control values. Twenty-four-hour urinary excretion of 4-hydroxyantipyrine, the major metabolite of antipyrine, likewise was reduced from 23.6% of the dose on the control trial to 14.8% of the dose during propranolol coadministration (0.1 less than P less than 0.2). Vd however, was nearly identical during both trials (0.62 L/kg). Thus propranolol prolongs the half-life and reduces the clearance or biotransformation rate of antipyrine, a drug whose clearance is independent of hepatic blood flow. Propranolol may influence the activity of hepatic microsomal enzymes responsible for drug hydroxylation.

Adult

[Injuries of the pelvis (author'r transl)].

Fractures of the pelvis impair the statics of the body and the dynamics of trunk and leg movement. Concomitant injuries obtain vital importance for the digestive tract, the urogenital system and the greater blood vessels. The operative reconstruction of acetabulum fractures is recommended increasingly. The late results concerning prevention of arthrosis, however, are not convincing. Posterior marginal fractures of the acetabulum, such as those to be found after posterior luxation of the hip joint, should be fixed by operation.

Acetabulum

Pharmacokinetics of chlordiazepoxide and metabolites following single and multiple oral doses.

Three healthy volunteers (2 male and one female) participated in single- and multiple-dose pharmacokinetic studies of oral chlordiazepoxide (CDX) hydrochloride. Following single 50-mg oral doses of CDX.HCl, absorption and elimination proceeded as apparent first-order processes. Values of absorption half-life were: 14.5, 189, and 18.9 minutes; elimination half-lives were: 7.6, 9.8, and 12.6 hours. Disappearance of CDX was mirrored by appearance of its first active metabolite, desmethylchlordiazepoxide (DMCDX). During once-daily ingestion of 50 mg of CDX.HCl, observed values of CDX accumulation half-life (0.0, 5.8, and 52.5 hours) differed substantially from values predicted based upon the single-dose study; pre-dose steady-state CDX blood concentrations also differed from the predicted values. Accumulation half-lives for the metabolite DMCDX were: 17.7, 9.9, and 15.8 hours. Accumulation in blood of a second active metabolite, demoxepam (DMX), proceeded with half-life values of 21.1, 34.2, and 78.5 hours. Minimum steady-state concentrations of DMCDX and DMX exceeded those of the parent compound. Thus accumulation and persistence of at least two active metabolites during long-term treatment with chlordiazepoxide renders the drug suitable for single-daily dose therapy of anxiety.

Adult

Factors influencing blood concentrations of chlordiazepoxide: a use of multiple regression analysis.

Three groups of male and female subjects aged 24-74 years received 25, 100, or 200 mg of chlordiazepoxide hydrochloride by mouth as a single dose or as two divided doses. The relation of plasma or whole blood concentrations for chlordiazepoxide (CDX) and its metabolite, desmethylchlordiazepoxide (DMCDX), to time since the last dose, weight, age, and sex were determined by simple and multiple regression analyses. Both CDX and DMCDX levels were negatively correlated with weight. Concentrations of CDX decreased, while those of DMCDX increased, with the time since the last dose. Lower levels of both drugs were associated with female sex, and lower levels of DMCDX were noted with increasing age. In the largest sample group, age and weight were more important variables than sex in accounting for CDX and DMCDX. Sex was of significance, and more important than time or age in explaining the variance of CDX in one series of observations. Multiple regression analysis is a useful approach to assessing interrelated factors influencing blood levels of drugs, especially when combined with a consideration of the interactive components of variance. Age and sex, in addition to weight and time, may be important factors that deserve further attention.

Adult