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Biomedical subjects

C L Nash

Publications and source records attributed to C L Nash.

At least 37 records · Page 2Linked to original sources
PubMed1982

Incidence of mitral valve prolapse in adolescent scoliosis and thoracic hypokyphosis.

Seventy-four patients with adolescent scoliosis underwent cardiac examination and M-mode echocardiography to detect the presence of mitral valve prolapse (MVP). Twenty-one (28%) had echocardiographic evidence of MVP, whereas 18 had auscultatory findings of a nonejection click or late systolic murmur. A subset of 41 patients had a family history of scoliosis and 37% had MVP. The incidence of MVP increased to 41% when a first degree relative, such as a sibling, parent, or offspring, had scoliosis. Thirty-six patients with scoliosis had additional thoracic hypokyphosis (straight back) and 13 (36%) had MVP. The incidence of MVP was 48% when the scoliosis and hypokyphosis were hereditary and increased to 53% when a familial history of skeletal abnormality was present. This study indicates a high incidence of MVP in patients with scoliosis and hypokyphosis, especially when the cardiac and skeletal systems may be affected by a generalized soft-tissue defect.

Adolescent↗
PubMed1979

Risks of exposure to X-rays in patients undergoing long-term treatment for scoliosis.

Thirteen healthy teenage girls with idiopathic adolescent scoliosis were studied using multiple thermoluminescent dosimeters while undergoing standard diagnostic roentgenograms. Average organ doses for each anteroposterior and lateral examination were calculated for bone marrow, gastrointestinal tract, lungs, breast tissue, and gonads. Given an average of twenty-two roentgenograms over a three-year Milwaukee brace-treatment program, the increase in organ carcinogenic risk due to x-ray radiation ranged from 3.4 to fifteen per million (1.3 per cent to 7.5 per cent), except for breast tissue which increased from 140 to 290 per million (110 per cent). Using posteroanterior rather than anteroposterior exposures reduced the increased risk to 5.3 per million (3.8 per cent). The genetic risks of scoliosis roentgenographic studies were considered to be negligible, especially with gonadal shielding and infrequent roentgenograms made every three to four months. Good technique and judicious ordering of roentgenograms added significantly to the safety of the patient.

Bone Marrow↗
PubMed1977

Mutagenicity of the triazine herbicides atrazine, cyanazine, and simazine in Drosophila melanogaster.

Assays for dominant lethal mutations, sex-linked recessive lethal mutations, and chromosomal breakage, nondisjunction and loss were performed on Drosophila melanogaster males treated by injection or by larval feeding of the herbicides atrazine (2-chloro-4-ethylamino-6-isopropylamino-1,3,5-triazine), cyanazine [2-chloro-4-(1-cyano-1-methylethylamino)-6-ethylamino-1,3,5-triazine], or simazine [2-chloro-4,6-bis-(ethylamino)-1,3,5-triazine]. The three herbicides significantly increased the rate of apparent dominant lethals, but this reduction in egg hatch was probably due to physiologic toxicity to sperm. Atrazine significantly increased X-linked recessive lethals and X or Y loss after treatment by larval feeding. Injection of simazine elevated X-linked lethals, whereas treatment by larval feeding did not. None of these herbicides significantly increased partial loss of the Y chromosome nor sex chromosome nondisjunction. Much larger experiments are needed to determine with confidence the mutagenic potential of these herbicides.

Animals↗
PubMed1974

Comparative denitrification of selected microorganisms in a culture medium and in autoclaved soil.

The denitrifying behavior of selected soil bacteria was compared in a culture solution and in soil that was sterilized by autoclaving. The essential characteristics concerning nitrate reduction and the formation of nitrogenous gases did not change significantly for most bacteria in the two environments. Bacteria whose denitrification product was nitrous oxide evolved the same gas both in soil and in a liquid system, whereas other bacteria formed only nitrogen gas. The validity of laboratory observations in relation to field studies in the domain of denitrification is discussed and evaluated.

Aerobiosis↗
PubMed1974

The effect of corrective surgery on pulmonary function in scoliosis.

Pulmonary function was studied in thirty-five patients before, during, and immediately after major orthopaedic operations. One group of twenty patients had corrective procedures for idiopathic scoliosis. Fifteen patients had operations involving the extremities. In the patients with scoliosis were found that pulmonary mechanics, as expressed by flow resistance and elastic compliance, deteriorated during the operation; that pulmonary right-to-left shunting increased and arterial oxygen tension on air decreased immediately postoperatively; and that vital capacity was greatly reduced after the operation. No significant changes took place in the rest of the patients. We concluded that corrective operations for idiopathic scoliosis are associated with major reductions of pulmonary function in the immediate postroperative period, so that postoperative respiratory failure would be a risk in patients who had compromised pulmonary function preoperatively. We therefore recommend pulmonary function testing preoperatively and outline one approach to this problem.

Adolescent↗