Biomedical subjects

C Riegger

Publications and source records attributed to C Riegger.

3 recordsLinked to original sources

PubMed2005

Repeated oral once daily intake of increasing doses of the novel synthetic genistein product Bonistein in healthy volunteers.

Bonistein is a new product consisting of > 99.5 % synthetic genistein, an isoflavone with phyto-oestrogenic properties, which might be a safe and efficacious alternative for the prevention of post-menopausal bone loss to the traditional hormone replacement therapy. A randomised, open-labelled and sequential-group phase I study was performed to assess safety, tolerability and pharmacokinetic characteristics of oral administrations of Bonistein. Thirty healthy volunteers received in three subsequent groups 30, 60 or 120 mg once daily for 14 days. For the pharmacokinetic profiles of Bonistein, blood samples were taken on study Days 1 (after first dose) and 14 (steady state). Repeated intake of Bonistein was well tolerated. A total of 33 adverse events were reported, mainly of mild intensity. No relevant changes in clinical laboratory or vital signs were observed. The pharmacokinetic characteristics of Bonistein revealed comparable results for extent and rate of absorption on Days 1 and 14. Both AUC and C (max) values of Bonistein increased in proportion with the dose.

Administration, Oral↗

PubMed1991

Relationship between lower limb dynamics and knee joint pain.

To test the hypothesis that appropriate and timely neuromuscular control of limb motions plays an important role in the preservation of joint health, we kinematically and kinetically examined the behavior of the legs of young adult subjects at heel strike during natural walking. We compared a group of 18 volunteers, who, we presumed, were preosteoarthrotic because of mild, intermittent, activity-related knee joint pain, with 14 age-matched asymptomatic normal subjects. The two groups of subjects exhibited similar gait patterns with equivalent cadences, walking speeds, terminal stance phase knee flexion, maximum (peak) swing angular velocity, and overall shape of the vertical ground reaction. However, our instrumentation detected statistically significant differences between the two groups within a few milliseconds of heel strike. In the knee pain group, the heel hit the floor with a stronger impact in this brief interval. Just before heel strike, there was a faster downward velocity of the ankle with a larger angular velocity of the shank. The follow-through of the leg immediately after heel strike was more violent with larger peak axial and angular accelerations of the leg echoed by a more rapid rise of the ground reaction force. This sequence of events represents repetitive impulsive loading, which consistently provoked osteoarthrosis in animal experiments. We refer to this micro-incoordination of neuromuscular control not visible to the naked eye as "microklutziness."

Adult↗

PubMed1987

Effects of a calcium entry promoting 1,4,5,7-tetrahydro-furo[3,4-b] pyridine derivative on Na+-, Ca2+- and Mg2+-dependent bioelectrical activity of Purkinje fibres and papillary muscles.

4-(2-Difluoromethoxyphenyl)-2-methyl-5-oxo-1,4,5,7-tetrahydro- furo[3,4-b]pyridine-3-carboxylic acid ether ester (CGP 28 392), a dihydropyridine derivative with an annellated lactone ring, was examined in automatically discharging calf Purkinje fibres. Velocity of spontaneous depolarization during both the early and the late phase of the diastolic pause and the rate of rise of the action potential were increased, with the threshold potential at which the upstroke is generated being unaltered. These findings are discussed in terms of ionic mechanisms, including in particular the contribution of sodium ions during the late phase of the diastolic depolarization and the novel type of calcium channel which is supposed to contribute to pacemaker depolarization and action potential initiation. In general, the effects of equimolar concentrations of nifedipine were opposite to those of CGP 28 392. At 1 X 10(-5) mol/l, however, both CGP 28 392 and nifedipine accelerated the late phase of diastolic depolarization. In electrically stimulated, partially depolarized guinea-pig papillary muscles, CGP 28 392 also prolonged the slow action potential and markedly increased inotropism. In equimolar concentrations nifedipine shortened the slow action potential and inhibited contractility. The effects of CGP 28 392 are thus compatible with facilitation of calcium entry and--in Purkinje fibres--also with enhancement of fast sodium conductivity.

Action Potentials↗