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Biomedical subjects

B Tillmann

Publications and source records attributed to B Tillmann.

113 records · Page 7Linked to original sources
PubMedDate not supplied

[Polychrome sequential labeling of subchondrial bone tissue in early and advanced stages of gonarthrosis in male STR/IN-mice].

Polychrome sequential labeling is used to study the dynamic of subchondral bone sclerosing during developing osteoarthrotic cartilage lesions in knee joints of male STR/1N-mice. The applied technique gives detailed information about site and time of new bone formation in the subchondral tissue using four different colored vital markers. Whereas control animals show regular bone deposition with a circumferential, concentric arrangement of fluorochromes along the various trabeculae, STR/1N-mice with osteoarthrotic cartilage lesions displayed fluorescence bands arranged eccentrically around the marrow cavities always pointing towards the cartilage lesions. The results also demonstrate, that the linear separation between the first label and the anatomic surface of the bone marrow cavity varies considerably in the individual experimental groups. Compared to control knee joints, which show appositional bone growth rates of 25 to 50 microns per 70 days, osteoarthrotic mice reveal increased bone growth rates during developing osteoarthrosis. In early osteoarthrotic cartilage lesions distances between the individual bands are distinctly larger in comparison to distances in advanced lesions. In both cases the rate of appositional bone growth exceeds bone formation in control animals 3 to 4 times.

Animals↗
PubMedDate not supplied

[Pharmacokinetic aspects of oral administration of etoposide].

BACKGROUND: Etoposide is a cytotoxic agent which is frequently employed in paediatric oncology and which is available for intravenous as well as oral application. Many advantages of the formulation for oral use have been opposed by concerns about its interindividually varying bioavailability. The influence of the dosage of etoposide on its activity and toxicity ("schedule dependency") has also been discussed. The present paper deals with the pharmacokinetics of oral etoposide focusing on the interindividual variability. PATIENTS: Sixteen patients aged between 3 and 73 years received oral etoposide at a dosage of 28 mg/m2 to 149 mg/m2 in combination with oral trofosfamide for palliation. METHOD: HPLC was used to measure total and free serum etoposide in 16 patients, and the etoposide concentration in several urine samples from 8 patients. Pharmacokinetic parameters were normalized to a dosage of 100 mg/m2. RESULTS: The peak serum concentration, the time to peak concentration, the area under the concentration-time curve, the terminal half-life and the apparent clearance after oral application were calculated to be 6.7 micrograms/ml, 2.1 h, 51.8 (microgram.h/ml)/(100 mg/m2), 5.6 h, and 40.3 ml/min for total etoposide, and 0.23 microgram/ml, 1.9 h, 1.76 (microgram.h/ml)/ (100 mg/m2), 5.9 h, and 1172 ml/min for free serum etoposide, respectively. On an average, urinary recovery of etoposide was 21% of the oral dose. The fraction of free etoposide was calculated to be close to 4%. Regarding the systemic exposure to etoposide, a variation coefficient of 40% was determined. Additional studies showed that the interindividual variability mainly concerned the peak levels, while the duration for which intermediate etoposide levels were maintained varied less between individuals. On simulating different dosage schedules, it was seen that the duration of intermediate concentrations (0.5-2 micrograms/ml) may be extended significantly by dividing the daily dose of etoposide into two oral applications. CONCLUSION: The total systemic exposure under oral etoposide treatment varies considerably between individuals. Extended intervals of intermediate etoposide concentration and less variation are, however, possible with oral therapy. Dividing the daily dose into two applications seems advisable. Future studies are warranted to test hypotheses on pharmacokinetic-pharmacodynamic aspects by pharmacological drug monitoring.

Administration, Oral↗
PubMedDate not supplied

[Morphology of a pelvitrochanteric nearthrosis in proximal hip dislocation].

A joint between the pelvis and the minor trochanter on the right hip of a 87 year old female will be investigated. The investigation includes the joint between the femoral head and the secondary socket. An analyse of the cartilage and the cancellous bone structure shows, that the joint pressure will be transmitted not only by the hip joint but also by the new joint.

Animals↗
PubMedDate not supplied

[Embryonic development of the hip joint].

Articular elements, joint cavity and intra-articular structures of the human hip joint are completely developed at the end of the embryonic period (8. week). The fetal period is characterized by growth of articular elements, by vascularization of the primordial skeleton and by the ossification of the acetabulum.

Cartilage, Articular↗