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Biomedical subjects

J M Vogel

Publications and source records attributed to J M Vogel.

At least 73 records · Page 4Linked to original sources

The development of recognition memory for the left-right orientation of pictures.

3 studies examined the development of recognition memory for the left-right orientation of pictures of common objects. In study 1, 5-year-olds, 9-year-olds, and college students were shown 20 pictures of objects. Subsequently, they were tested on their ability to discriminate between 10 of these pictures and their left-right mirror images and between the other 10 pictures and completely new ones. There were large developmental differences in memory for orientation, although all age groups could discriminate accurately between familiar pictures and completely new ones. In studies 2a and 2b, training concerning the relevance of orientation improved second and fourth graders' long-term memory for this characteristic, but training effects were minimal for kindergartners. However, even kindergarten children showed accurate short-term memory for orientation on the task used for training. In contrast to study 2, study 3 produced accurate long-term memory for orientation in kindergarten children by using a verbal training procedure. Results are discussed in terms of the range of memory factors involved in children's mirror-image confusions and in terms of general implications for the development of recognition memory.

Adolescent↗

Bone mineral changes: the second manned Skylab mission.

The mineral content of the central os calcis, and distal radius and ulna was measured by the monoenergetic photon absorptiometric technique pre- and postflight on the the SL-3 crewmen. No significant changes were observed in the radius and ulna. Only the SPT showed a loss in calcaneal mineral which slowly returned to preflight levels by the 87th postflight day.

Adult↗

Effect of the diphosphonate EHDP on bone mineral metabolism during prolonged bed rest.

The effect of disodium ethane-1-hydroxy-1, 1-diphosphonate (EHDPTM) on bone mineral metabolism was tested in 4 healthy young men during 20 weeks of continuous bed rest. Two subjects received an oral dose of 5 mg/kg/day and the other 2 20 mg/kg/day. The low dose had two minor effects: the increase in bone accretion rate which usually occurs during bed rest was prevented, and there was an accentuation of the bed rest induced increase in hydroxyproline excretion. Skeletal mineral loss, assessed by calcium balance measurements and gamma ray absorptiometry of the calcaneus, occurred at the rate previously noted in untreated control subjects. Two types of drug effect were apparent at the higher dosage: one was immediate and sustained--a rise in serum phosphorus concentration and a fall in serum alkaline phosphatase activity. The other was delayed and progressive--a decline in urinary hydroxyproline excretion and in the rates of bone accretion and resorption. Skeletal mineral loss may have been affected; the usual negative mineral balance developed during the first half of the study, then disappeared during the last few weeks. However, gamma ray absorptiometry revealed no attenuation of the calcaneal mineral losses.

Adult↗

Effect of potassium depletion in normal males: an Apollo 15 simulation.

In the course of Apollo 15, physiologic abnormalities, manifested by ectopic activity on the ECG and unusual alterations in excerise tolerance, occurred in the crew of the Lunar Excursion Module. These were associated with decreases in total body potassium, measured by 42K, of 10% and 15%. The possibility of inadequate potassium (K plus) intake existed. A simulation study was performed prior to Apollo 16, corresponding in duration to Apollo 15. Subjects endured the same sleep aberrations and caloric expenditure as the Apollo 15 astronauts. Subjects consumed a diet containing only 15 mEq/d of K plus during the entire 12 d of absolute bedrest. ECG was continuously monitored, body fluid compartments and total body K plus were measured at intervals by radionuclide methods, electrolyte balance was determined daily, and excercise and orthostatic tolerances were determined prior to and after bedrest. In spite of decreases in total body K plus measured by 42K of 14.5% and 10.5%, and by potassium balances of 3.3% and 6.5%, respectively, neither of the two subjects developed symptomatic hypokalemia. Minor ECG abnormalities were noted in one subject. Orthostatic and exercise tolerance showed only those changes expected as a result of bedrest. Muscle strength was unaffected. Study implications and reasons for discrepancies between K plus loss measured by balance techniques and 42K are reviewed.

Adult↗

The effect of supplemental oral phosphate on the bone mineral changes during prolonged bed rest.

Five healthy young men were studied during 24-30 wk of continuous bed rest. During the first 12 wk of bed rest, untreated subjects increased calcium excretion in the urine by 109 mg/day and in the feces by 147 mg/day. The rate of total body calcium loss was 0.5-0.7% per month. Losses of central calcaneus mineral, assessed by gamma ray transmission scanning, occurred at a tenfold higher rate, whereas the mineral content of the radius did not change. Changes in phosphorus balance resembled the calcium pattern, and increased excretion of nitrogen and hydroxyproline also occurred during bed rest. Upon reambulation, the subjects' calcium balance became positive in 1 month and recovery of their calcaneus mineral was complete within 10-20 wk. Treatment with potassium phosphate supplements (1327 mg P/day) entirely prevented the hypercalciuria of bed rest, but fecal calcium tended to increase. During the first 12 wk, calcium balance was slightly less negative (mean - 193 mg/day) than during bed rest without added phosphate (mean - 267 mg/day). This effect was not seen during the second 12 wk of bed rest. The patterns of magnesium excretion were similar to those of calcium. Fecal and urinary phosphorus excretions were doubled, and phosphorus balance became positive (+ 113 mg/day). Mineral loss from the central calcaneus was similar to that of untreated subjects. It is concluded that this form of phosphate supplementation reduces urinary calcium excretion but does not prevent bone loss during bed rest.

Administration, Oral↗