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Biomedical subjects

C Gerber

Publications and source records attributed to C Gerber.

At least 127 records · Page 7Linked to original sources

The lower-extremity musculature in chronic symptomatic instability of the anterior cruciate ligament.

We studied the musculature of the lower extremity in forty-one patients with chronic symptomatic instability of the anterior cruciate ligament. Computed tomographic and clinical measurements of the limb were taken at levels fifteen and twenty-five centimeters proximal to the medial joint line and ten centimeters distal to it. Biopsy specimens from the vastus lateralis of both lower extremities were analyzed by histochemistry and electron microscopy. Computed tomography revealed a decrease in the muscle square area of the affected thigh of 8 per cent as compared with the control lower extremity. There was quadriceps atrophy of 10 per cent and hamstrings atrophy of only 4 per cent. The atrophy of the vastus medialis was significantly greater than that of the entire quadriceps. Histochemistry revealed a similar decrease in fiber size for all fiber types, and hence no shift in fiber type. Electron microscopy showed an increase in intracellular fat but no change in mitochondrial volume density or capillarization.

Adolescent↗

Evaluation of the levels of free and total amitriptyline and metabolites in the plasma and brain of the rat after long-term administration of doses used in receptor studies.

This study was conducted in order to investigate the level of amitriptyline (AT) and its metabolites. Three separate experiments were carried out. In two of these experiments, rats were treated over 7 days with IP doses of AT (10 mg/kg in experiment A and 2 X 20 mg/kg in experiment C). The rats were sacrificed either 2 (experiment C) or 12 h (experiments A and C) after the last dose. In experiment B, rats were sacrificed 2 or 12 h after a single dose of 20 mg/kg AT. The results of these experiments showed the following: in experiment A only AT was measurable in the brain and in the plasma, in contrast to experiments B and C, where NT and the hydroxylated metabolites AT-OH and NT-OH reached significant levels in the plasma and in the brain. The concentrations of AT-OH, NT-OH, and NT (12-h values) that were found in the brain are probably not pharmacologically relevant. The 12-h plasma values of all compounds tested were, even with the highest dose, lower than those expected to be clinically effective in man. Our results suggest that AT, at higher doses, may induce its own metabolism. The free plasma levels of this drug and its metabolites are higher in man than in the rat. The possible implications of these results in the use of antidepressants in the treatment of depression are discussed.

Amitriptyline↗

Observations concerning the limited mobilisation cast after anterior cruciate ligament surgery.

A limited mobilisation cast (LMC) with hinges locked at 20 and 60 degrees has been advocated for the care after anterior cruciate ligament (ACL) surgery. The brace presumably limits motion to 20 and 60 degrees and prevents straining of the ACL. Extension of more than 20 degrees as well as anterior drawer forces are known to strain the ACL. We have therefore tested whether the LMC reliably limits the desired range of motion: Extension of more than 20 degrees was found in 11 of 12 patients and averaged 12 degrees. The long leg cast reduced a 30 degree anterior drawer in unstable knees by 70%, a Lenox-Hill-Derotation Brace by 53% and the LMC by only 14%. It was concluded that a modified Lenox-Hill Brace locked at 30 and 60 degrees of flexion provides better stress-protection of the ACL than a LMC and that the safety of the conventional long leg cast should be remembered in legs with unfavourable soft tissue configurations. If a LMC is used, it should be fixed to the trunk with a waist- or shoulder-strap and the hinges must be freely adjustable.

Adolescent↗

Biomechanical analysis of the knee after rupture of the anterior cruciate ligament and its primary repair. An instant-centre analysis of function.

Sixty-five knees were subjected to a kinematic analysis using the instant-centre technique in order to determine the effect of deficiency of the anterior cruciate ligament on the biomechanics of active movement in the knee. The instant-centre pathway in acute ruptures of the anterior cruciate ligament was found to have a specific abnormality. This corresponded with a positive pivot-shift sign, but was present even when that sign was not clinically detectable. Primary repair using a transosseous wire suture did not usually abolish the biomechanical abnormality. The data provide a possible explanation for the doubtful prognosis of primary repair of this ligament and encourage clinical and biomechanical evaluation of alternative procedures such as primary augmented repair.

Adult↗

Sleep, EEG and mental function changes in senile dementia of the Alzheimer's type.

Sleep, EEG and mental function variables were studied in 44 subjects diagnosed as having probable senile dementia of the Alzheimer's type (SDAT) and 22 controls matched for age and minimal depression. Results indicate that sleep, EEG and mental function variables all undergo significant change even in the early, mild stage of SDAT, with further change in the moderate and severe stages of dementia. Mental function variables also underwent significant decline across levels of dementia. Sleep and mental function variables had strong power in correctly classifying subjects into control vs. mild dementia groups (90 and 100%, respectively). Dominant occipital rhythm frequency, a clinical EEG measure, also discriminate as well (75%). The results indicate that sleep and EEG variables discriminate well for early, mild SDAT in minimally depressed aged individuals.

Aged↗

Oestrogens, gonadotropins and prolactin after intra-vaginal administration of oestriol in post-menopausal women.

Serum total oestrone, 17 beta-oestradiol and oestriol concentrations and FSH, LH and prolactin values were measured radioimmunologically in post-menopausal women before and after intra-vaginal application of 0.5 mg oestriol. While oestrone and oestradiol were not altered, there was a 3100% increase in the mean oestriol values within 1 or 2 h; pre-treatment levels were again reached 8 h later. Both gonadotropins were moderately decreased, the serum prolactin values appeared to be slightly elevated. Repeated intra-vaginal application of oestriol resulted in a significant rise of the mean serum oestriol levels while the other oestrogens remained unchanged. The same was true for FSH and LH, a considerable negative feedback was therefore excluded. Again there seemed to be a slight rise of the prolactin secretion. It was concluded that intra-vaginal administration of oestriol is a most suitable local and systemic oestrogen replacement therapy, which is more effective than the oral regimen.

Absorption↗

Blood and urine fluoride concentrations associated with topical fluoride applications on dog gingiva.

The circulatory uptake and urinary excretion of topical fluoride were investigated by applying a sodium fluoride solution containing 18F for six min to healthy gingiva of four adult dogs. Blood and urine samples were taken a regular intervals. Maximal fluoride in blood represented 0.02-0.05% of the applied dose and occurred four min after completion of the application. By 6.0 h, 0.02-0.06% of the applied dose had been excreted in urine. Preliminary data showed that this represented about 8.8% of the fluoride absorbed through the gingiva.

Animals↗