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Biomedical subjects

J R Beljan

Publications and source records attributed to J R Beljan.

At least 19 recordsLinked to original sources
PubMed1977

Space motion sickness medications: interference with biomedical parameters.

The possibility that drugs administered to Skylab 3 (SL-3) and 4 (SL-4) crewmen for space motion sickness may have interfered with their biomedical evaluation in space was investigated. Healthy volunteers received combinations of Scopolamine/Dexedrine for four days in regimens similar to those used in these missions. Urine samples, heart rate, body temperature, mood and performance were analyzed for drug-related changes. Twenty-four hour urine samples were analyzed by the same procedures as those used to analyze the flight samples. Hormone concentrations determined included cortisol, epinephrine, norepinephrine, aldosterone and antidiuretic hormone (ADH). In addition, volume, specific gravity, osmolarity, sodium (Na), potassium (K), calcium (Ca), magnesium (Mg), chloride (Cl), inorganic phosphate, uric acid and creatinine were measured. Performance was not affected by the Scopolamine/Dexedrine. The drug combination increased daily mean heart rate (HR) significantly in all the subjects and daily mean rectal temperature (RT) in some of the subjects. A 2-4 hr phase shift in the HR circadian rhythm was also observed which indicates that internal circadian synchrony was disturbed by the drugs. Psychological and subjective evaluation indicated that the subjects could usually identify which days they were given the drugs by an increase in tension and anxiety, decreased patience, restlessness, decreased appetite, difficulty in sleeping and feelings of increased heart rate and body temperature. Urinary electrolytes were not changed significantly by the drug, but marked and significant changes occurred in urine volume and hormone excretion patterns. Scopolamine/Dexedrine caused consistent elevations in urinary cortisol and epinephrine and a transient elevation in ADH. Norepinephrine excretion was decreased, but there was no significant change in aldosterone excretion or in 24 hr urine volume. A comparison of these findings with the first four days of inflight data from the SL-3 and SL-4 missions leads to the conclusion that the dramatic increases in aldosterone excretion during the first three days of spaceflight probably can be directly attributed to weightlessness, whereas the antimotion sickness medication could have substantially contributed to the early increased excretion of epinephrine and cortisol during these missions.

Adult↗
PubMed1977

The effect of low light intensity on the maintenance of circadian synchrony in human subjects.

The light-intensity threshold for humans is not known. In past space flights owing to power restrictions, light intensities have been minimal and reported to be as low as 15 ft. c. This study was conducted to determine whether the light (L)/dark (D) environment of 16L : 8D at the relatively low light intensity of 15 ft. c. was adequate for the maintenance of circadian synchrony in human subjects. Six healthy male subjects aged 20-23 years were exposed for 21 days to a 16L : 8D photoperiod. During the first 7 days the light intensity was 100 ft. c.; it was reduced to 15 ft. c. during the next 7 days and increased again to 100 ft. c. during the last 7 days of the study. Rectal temperature (RT) and heart rate (HR) were recorded continuously throughout the 21 days of the study. In the 100 ft. c. 16L : 8D the RT and HR rhythms remained stable and circadian throughout. When the light intensity was decreased to 15 ft. c. the periodicity of the HR rhythm was significantly decreased and this rhythm showed marked instability. In contrast the period of the RT rhythm did not change but a consistent phase delay occurred due to a delay in the lights-on associated rise in RT. These divergent effects on these two rhythms in internal desynchronization and performance decrement during the 15 ft. c. exposure. The data emphasize the need for establishing accurately the minimal lighting requirements for the maintenance of circadian rhythms of humans in confined environments.

Adult↗
PubMed1977

The effect of chronic heparin administration on the mineralization of an experimental osseous defect.

Adult roosters with experimental circular osteotomy defects in the metatarsus were placed on chronic heparin therapy. In vivo measurement of bone mineral content changes of the osteotomy using Iodine-125 show no adverse affect of heparin treatment on remineralization. However, the weight of dry-defatted femurs was decreased and suggests that there was significant heparin-induced systemic bone demineralization.

Animals↗
PubMed1976

Psychologic and psychophysiologic response to 105 days of social isolation.

The responses of nine subjects to 105 d of social isolation are reported. The study reveals that crew selection plus ongoing support by psychiatric staff permits continued function in an exotic milieu. Prediction of psychophysiologic symptoms was possible using paper and pencil tests. Trait anxiety was altered by the isolation in a psychologically healthy direction. Sudden time shifts of 8 h led to an immediate significant increase in depression, aggression, and hostility, and are accompanied by marked increases in physical symptoms. During the first free-running phase of the experiment, significant shifts were found on four psychological measures. The shifts indicate that subjects became less trusting, more orderly, more routinized, less energetic, and more depressed. A reducer-augmenter scale predicted the number of psychophysiologic complaints reported by individual subjects while isolated. A group interaction effect on circadian rhythms was isolated but needs further examination.

Adult↗
PubMed1975

The effect of diethylstilbestrol on the rate of osseous repair, bone integrity, and plasma calcium in the adult avian.

The effect of diethylstilbestrol on healing experimental osseous defects in adult roosters was studied by means of I-125 photon absorptiometry. Although the two dose levels utilized in this study both resulted in elevated plasma calcium and lipid levels and significantly increased the mineral and organic fractions of femoral bone, diethylstilbestrol treatment over a six-week period had no effect on the rate or magnitude of mineralization in the repairing osseous defect.

Absorption↗
PubMed1974

Osseous malrepair in calcium-deficient states.

A primary body tissue involved in metabolic change under the influence of gravity is bone. Osseous integrity is obviously essential for normal musculoskeletal activity; this is of particular importance in long manned space flights where some evidence suggesting calcium loss from bone exists. Studies in our laboratory, utilizing an avian model, have been on the effects of chronic calcium deficiency (or "nutritional secondary hyperparathyroidism"), particularly on bone repair. Quantitative methods to determine both the rate and quality of osseous defects have been developed. A calcium-deficient synthetic diet (0.002% calcium by weight, but otherwise nutritionally complete) has been formulated to permit the induction of true calcium deficiency states in adult, skeletally mature, male domestic fowl. This report is concerned with the effects of long-term calcium depletion on bone repair. It has been classically taught that bone injury repair is always preferentially treated by the body, despite skeletal calcium depletion. For the first time, we have been able to demonstrate that this is incorrect; in the chronic calcium-deficient state, an osseous defect will not be preferentially calcified at the expense of an already-decalcifying skeleton. Quantitative data demonstrate that healing patterns in bone vary in response to the duration of the calcium deficiency. In adult male fowl, calcium-deficient for ten months, bone repair is almost completely absent; in those calcium-deficient for six months, bone repair is both retarded and imperfect; repair is absent even when supplemental calcium is administered at the time of osseous injury induction and thereafter. The conclusions to be drawn from this study are that (i) bone repair is adversely affected in the calcium-deficient state, (ii) the rate and quality of bone repair are directly related to the duration of the calcium-deficient state, and (iii) supplemental calcium administration in chronic calcium-deficient states initially retards, rather than enhances, bone repair. These conclusions have direct relevance to long-term manned space flight.

Animals↗
PubMed1973

Congenital hypertrophic pyloric stenosis.

In a large metropolitan general hospital, a high incidence of congenital hypertrophic pyloric stenosis was noted in non-Caucasian groups. Bile-free emesis was consistently reported, and admission was frequently delayed. A prompt diagnosis following admission was not always possible. Unequivocal palpation of a right upper quadrant mass was successful in less than half of the patients in this series, and radiographic studies were helpful in establishing the proper diagnosis in the remainder. Liver fracture can occur with improper abdominal palpation techniques. Despite a surprisingly high complication rate, the ultimate result of operative therapy is uniformly excellent. Three patients not operated upon who were followed for more than two years still have evidence of gastric dysfunction. Postoperative emesis following adequate operation is not unusual, occurring approximately one-third of the time. When postoperative emesis is protracted, incomplete pyloromyotomy should be considered.

Female↗