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C Leach

Publications and source records attributed to C Leach.

42 records · Page 3Linked to original sources
PubMed1976

Mineral and nitrogen balance study observations: the second manned Skylab mission.

A metabolic study of the effects of space flight on various chemical elements, particularly those with special revelance to the musculoskeletal system, was carried out on the three astronauts of the SL-3 mission for 21 d preflight, during the 60 d flight phase, and for 17 d postflight. The study required of the cooperating crewmen quite constant dietary intake, continuous 24-hour urine collections and total fecal collections. Urinary calcium was significantly increased during flight in all three crewmen with man-to-man variation in pattern and amount; the degree of calcium loss was, in general, similar to that in the prior study of the 28-d Skylab flight (SL-2). The similarity to bedrest immobilization in the pattern of urinary calcium increases and of total calcium shifts suggested that calcium losses would continue for a very long time. Significant losses of nitrogen and phosphorus occurred that were associated with observed reduction in muscle tissue. Both mineral and muscle losses occurred despite vigorous exercise regimens during flight. It was concluded that these studies give warning that capable musculoskeletal function may be significantly impaired during prolonged space flights lasting 1.5 to 3 years unless protective measures are developed.

Adult↗
PubMedDate not supplied

Mineral and nitrogen balance study: results of metabolic observations on Skylab II 28-day orbital mission.

Prediction that the various stresses of flight, particularly weightlessness, would bring about significant derangements in the metabolism of the musculoskeletal system has been based on various observations of long-term immobilized or inactive bed rest. The only attempt at controlled measurement of metabolic changes in space prior to Skylab, a study during the 14-day Gemini VII flight, revealed rather modest losses of important elements. The three astronauts of Skylab II consumed a planned day-by-day, quite constant, dietary intake of major metabolic elements in mixed foods and beverages and provided virtually complete collections of excreta for 31 days preflight, during the 28 days inflight, and for 17 days postflight. Analyses showed that, in varying degree among the crewmen, urinary calcium increased gradually during flight in a pattern similar to that observed in bed-rest studies: the mean plateau peak of urinary calcium excretion in the latter part of flight was double preflight levels. Fecal calcium excretion did not change significantly, but calcium balance, owing to the urinary calcium rise, became either negative or less positive than in preflight measurement. Increased excretion and negative balance of nitrogen and phosphorus indicated appreciable loss of muscle tissue in all three crewmen. Significant losses also occurred inflight in potassium, sodium, and magnesium. Based on the similarity in pattern and degree between these observations and those in bed rest of the losses in calcium, phosphorus, and nitrogen, musculoskeletal integrity would not be threatened in space flights of up to at least 3 months. However, if similar changes occur, indicative of continuing losses of these elements, in the planned Skylab flights for considerably more than 28 days, concern for capable musculoskeletal function should be serious for flights of very many months' duration, and greater research attention will need to be given to development of protective counter-measures.

Aerospace Medicine↗
PubMedDate not supplied

Cytodiagnosis of classic lobular carcinoma and its variants.

The well-known cytologic features of lobular carcinoma traditionally consist of modest cellularity and small, atypical cells lying singly or in small groups. However, lobular carcinoma is a common pitfall in the cytodiagnosis of breast lesions. Knowledge of its varied histologic appearance can help to prevent diagnostic difficulties. Among 55 consecutive cases of breast needle aspirates with histologic follow-up, 9 lobular carcinomas were identified. The surgical material was examined for the following histologic variants: (1) classic, (2) solid, (3) alveolar, and (4) mixed; it was correlated with the cytologic findings. Pure, classic lesions were the most likely cause of false-negative diagnoses. Two of nine lobular carcinomas were diagnosed as benign due to scant cellularity and cell smallness. Four of nine were cytologically misclassified as ductal type due to more abundant cellularity and larger cells. This could be attributed to the predominant alveolar or solid patterns present in three cases. Only three of nine were accurately classified as lobular carcinoma, and all had a significant classic histologic element. Another important feature that is highly suggestive of lobular carcinoma is the presence of cytoplasmic vacuoles. They were overlooked in three of four cases. This study suggested that the traditional cytologic features of lobular carcinoma are present only in tumors with a predominantly classic histologic pattern. Awareness of the variant patterns and their cytologic features, including more abundant cellularity, larger cells and clusters, and cytoplasmic vacuoles, will aid in correct classification.

Biopsy, Needle↗