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Biomedical subjects

C Hitchcock

Publications and source records attributed to C Hitchcock.

11 recordsLinked to original sources
PubMed1985

Gastrin release from dispersed gastrinoma cells: effects of calcium and calcium ionophore (A23187).

Dispersed single-cell suspensions of human gastrinoma tissue were incubated for 15, 60, and 120 min in a calcium-containing medium, (0.1, 2, 10 mM) in calcium-free medium and in calcium-free medium containing the calcium ionophore A23187 (0.01, 1, and 100 micrograms/ml). Supernatant and pellet (intracellular) gastrin levels were determined by radioimmunoassay. Supernatant gastrin levels remained stable over 120 min in calcium chloride or calcium gluconate containing medium, while intracellular pellet gastrin approximately tripled during the same incubation period. Total gastrin (supernatant plus pellet) approximately doubled during the 2-hr incubation in calcium. However, calcium (0.1, 2, or 10 mM) failed to produce a dose-dependent rise in supernatant, pellet, or total gastrin when compared to calcium-free incubates. Contrary to the expected gastrin response to calcium, supernatant and pellet gastrin levels were higher in incubates in calcium-free medium than in calcium-containing incubates. A23187 (0.01 or 1 mcg/ml) in a calcium-free medium decrease supernatant gastrin while high dose ionophore (100 mcg/ml) increased supernatant gastrin. All doses of ionophore stimulated pellet and total gastrin levels. Thus, it appears that the clinical augmentation of gastrin levels, seen with calcium challenge in vivo may not be solely due to changes in serum calcium.

Adult↗
PubMed1985

Normal standards for an incremental progressive cycle ergometer test.

One hundred healthy subjects (50 male and 50 female), selected to provide an even distribution of age (15 to 71 yr) and height (165 to 194 cm in males and 152 to 176 cm in females), underwent a progressively incremental (100 kpm/min each min) exercise test to a symptom-limited maximum. Measurements were made of O2 intake and CO2 output, ventilation and breathing pattern, heart rate and blood pressure, and rating of perceived exertion. The ventilatory anaerobic threshold was identified. Predictive data were derived for measurements at maximal and submaximal exercise. Maximal power output (Wmax) and oxygen intake (VO2max) varied with sex (0, male; 1, female), age (yr), and height (Ht, cm): Wmax = 20.4 (Ht) - 8.74 (Age) - 288 (Sex) - 1,909 kpm/min (SEE, 216; r, 0.858); VO2max = 0.046 (Ht) - 0.021 (Age) - 0.62 (Sex) - 4.31 L/min (SEE, 0.458; r, 0.869). The extent of leisure time activity exerted a positive influence on VO2max (r, 0.47; p less than 0.001); VO2max was also related to lean thigh volume (r, 0.79). Maximal heart rate (HR) declined as a function of age: HRmax = 202 - 0.72 (Age) beats/min (SEE, 10.3; r, 0.72). Maximal O2 pulse (O2Pmax) was related to height and was systematically higher in males than in females: O2Pmax = 0.28 (Ht) - 3.3 (Sex) - 26.7 ml/beat (SEE, 2.8; r, 0.86). Ventilation was closely related to CO2 output, and the maximal tidal volume was related to vital capacity. The VO2 increased linearly with power throughout the test; in an individual subject, the intercept of this relationship was positively influenced by weight and height.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1975

Ward environment in an inpatient drug dependence treatment unit: II. Attempts to improve ward environment.

Ward activity and atmosphere in a Drug Dependence Treatment Unit were found to be poor in a previous study. The results of two attempts to improve ward environment are reported. The arrival of an occupational therapist had a very slight and restricted effect on the level of patients' constructive activity, and produced only one significant change on the Ward Atmosphere Scale; patients perceived an increase in Practicality. There was, however, a consistent improvement in patients' Vigor and Friendliness mood scores following the arrival of the occupational therapist. A pilot project using cigarettes as reinforces for patient constructive activity produced little sustained effect. Possible reasons for the difficulties in managing drug-dependent patients are discussed, and suggestions made for improvement.

Affect↗