Search

The purpose of this study was to evaluate the effects of 9 d of immobilization and partial suspension on muscle function at the wrist. Twelve female subjects (19-27 yr) wore a cast suspended from the neck by a sling that immobilized muscles acting on the wrist. Atrophy, muscle damage indicators, isometric and isokinetic strength, reaction time, speed of movement, and fatigability were assessed. Forearm muscle cross-sectional area decreased by 4.1% following immobilization and suspension. There was no indication that significant muscle degeneration occurred during immobilization or when muscles resumed normal function. Isometric strength for flexion and extension decreased by 29.3 and 32.5%, respectively. Concentric strength decrements for flexion, extension, pronation, and supination ranged from 8.9-21.7% at 2.11 and 3.16 rad.s-1. Eccentric strength decrements at 2.11 rad.s-1 for the same movements ranged from 12.5-18.5%. Fatigability was unaffected. Greater relative strength losses compared to decreased muscle cross-sectional area may be the result of a decrease in contractile protein density or unidentified neural factors following immobilization and partial suspension. However, neuromuscular control of reaction time was not affected.

Collagraft (Zimmer and Collagen Corporation) consists of a mixture of porous beads composed of 60% hydroxyapatite and 40% tricalcium phosphate ceramic and fibrillar collagen. When mixed with autogenous bone marrow, it serves as an effective bone graft substitute. Since September 1986, this material has been used in a multiclinic prospective trial, randomized against cancellous iliac crest autografts in the treatment of long bone fractures. To date, 267 patients have entered this study with 128 patients receiving cancellous autograft and 139 patients receiving Collagraft. At 6- and 12-month follow-ups, Collagraft appears to function as well as autogenous graft when used in the treatment of acute long bone fractures.

The oxygen sensitivities of basic cell functions were compared to evaluate their significance as potential causes of the reversible growth inhibition produced in Escherichia coli by exposure to hyperbaric oxygen. Growth and net incorporation of radioactive glucose into cell structure, and specifically in to protein, were completely inhibited in approximately 1/20 of a generation by a gas phase containing 4.2 atmospheres of oxygen. The inhibition occured before there was significant decrement in cellular glucose transport, respiration, or intracellular concentration of adenosine triphosphate. The data indicate that fundamental steps leading to protein biosynthesis from glucose should be examined in the search for specific primary sites of oxygen toxicity.

In a sample of 150 Sukuma from north central Tanzania, immunoglobulin G, M, A, and E levels were studied in relation to the phenotypes in 22 polymorphic systems. No strong associations were detected, though there is a suggestion of an association between IgG and haptoglobin type, with elevation of mean levels in heterozygotes.