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Biomedical subjects

R Waters

Publications and source records attributed to R Waters.

105 records · Page 6Linked to original sources
PubMed1976

Effects of nerve stimulation on human muscle.

A phasic program of femoral nerve stimulation was used to reduce refractory knee flexion contractures in five patients. In one, rectus femoris was tenotomized before starting stimulation to reduce hip flexion contracture. Muscle biopsies were performed before and after 5 to 12 weeks of intermittent stimulation at separated sites on the same muscle. In the four patients where muscle contraction was isometric, type I fibers increased 3.7%, 6.4%, 48.4%, anand 30.4%, respectively. Both fiber types in each patient showed an increase in size ( p less than .001). In the tenotomized muscle, where contraction was isotonic at a shortened length, the proportion of type I fibers decreased from 40.2% to 25.4%, and their mean diameter also decreased (p less than .001). These observations suggest that the physical conditions of contraction may be more important than the pattern of neuronal discharge in determining the metabolic profile of human muscle fibers.

Axons↗
PubMed1975

The fate of UV-induced pyrimidine dimers in the nuclear and mitochondrial DNAs of Saccharomyces cerevisiae on various postirradiation treatments and its influence on survival and cytoplasmic "petite" induction.

The photoreactivability of UV-induced pyrimidine dimers in the nuclear and mitochondrial DNAs of Saccharomyces cerevisiae has been investigated in conjunction with the fate of these photoproducts following postirradiation dark incubation in saline and nutrient media. In all instances, survival and "petite" induction were measured. An attempt has been made to relate these results to present ideas on the repair of UV damages in DNA.

Cell Nucleus↗
PubMed1975

Dose dependence of the excision of ultraviolet-induced pyrimidine dimers from nuclear deoxyribonucleic acids of haploid and diploid Saccharomyces cerevisiae.

The yield of ultraviolet-induced dimers is similar for a fixed dose in both haploid and diploid Saccharomyces cerevisiae. The excision of these photo-products from the nuclear deoxyribonucleic acids of cells of both ploidies after ultraviolet incident doses of 2 times 10-3 to 4 times 10-3 ergs/mm2 decreased with the corresponding increasing dose. Postirradiation incubation in saline followed by a further incubation in nutrient medium increases the excision as compared to that seen in either nutrient medium or saline alone. Previous data regarding both pyrimidine dimer removal and the survival of haploid and diploid cells after ultraviolet irradiation and either immediate or delayed plating are discussed.

Centrifugation, Density Gradient↗
PubMedDate not supplied

Experience with implanted electrodes.

Implant units, manufactured by Medtronic, Inc., have been implanted in 31 patients for treatment of drop-foot. The principal problem encountered in this series was inflammatory reaction. This was observed in seven patients, and was serious enough in five to require removal of the implant. On the positive side, there have been no failures of the implanted equipment for periods of up to 7.3 years, although there is currently a question on one patient. There has also been no documented damage to the nerve from chronic stimulation. Fine wire elctrodes have been implanted intraneurally in a series of animals and in three patients. Preliminary results look encouraging, and this approach seems to hold considerable promise for a new generation of electrode design.

Amputees↗
PubMedDate not supplied

Experience with implanted electrodes at Rancho Los Amigos Hospital.

Implanted units, manufactured by Medtronic, Inc., have been implanted in 31 patients for treatment of drop-foot. The principal problem encountered in this series is inflammatory reaction, which was observed in 7 patients and was serious enough in 5 to require removal. Theree have been no failures of the implanted equipment for periods of up to 7.3 years, although there is currently a question in 1 patient. There has also been no documented damage to the nerve due to chronic stimulation. Fine wire electrodes have been implanted intraneurally in a series of animals and in 3 patients. Preliminary results look encouraging, and this approach seems to hold considerable promise for a new generation of electrode design.

Electric Stimulation Therapy↗