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Biomedical subjects

R Fiser

Publications and source records attributed to R Fiser.

6 recordsLinked to original sources
PubMed1992

Microgravity effects on sea urchin fertilization and development.

Gravity has been a pervasive influence on all living systems and there is convincing evidence to suggest that it alters fertilization and embryogenesis in several developmental systems. Notwithstanding the global importance of gravity on development, it has only been recently possible to begin to design experiments which might directly investigate the specific effects of this vector. The goal of this research program is to explore and understand the effects of gravity on fertilization and early development using sea urchins as a model system. Sea urchin development has several advantages for this project including the feasibility of maintaining and manipulating these cells during spaceflight, the high percentage of normal fertilization and early development, and the abundant knowledge about molecular, biochemical, and cellular events during embryogenesis which permits detailed insights into the mechanism by which gravity might interfere with development. Furthermore, skeletal calcium is deposited into the embryonic spicules within a day of fertilization permitting studies of the effects of gravity on bone calcium deposition.

Animals↗
PubMed1980

Low efficacy radiography of children.

Radiographic procedures performed at a 100-bed pediatric hospital were reviewed jointly by a radiologist and the primary physician staff. The reviewers judged several procedures to be performed unnecessarily, with undue patient risk or cost. Low efficacy examinations were divided into two categories: (1) low-yield examinations with significant gonadal radiation as well as significant cost, and (2) low-yield examinations with low gonadal radiation but significant cost. A joint policy recommendation was then delivered to the house staff concerning appropriate indications for the performance of these low-yield procedures. This active review process is submitted as a model for other medical facilities that seek to reduce risk and cost to the pediatric patient.

Angiography↗
PubMed1975

Metabolic and hormonal studies comparing three parenteral nutrition regimens in infants.

Metabolic and hormonal studies were performed in 6 infants during the first 3 months of life while receiving 3 different types of parenteral nutrition: 1) 20% glucose and a nitrogen source (Dudrick's method) 2) 12% glucose, a nitrogen source and soybean fat emulsion (Intralipid method) and 3) 12% glucose, a nitrogen source and 1% alcohol (Babson's method). All three regimens provided positive nitrogen balance of similar magnitude. The substrate-hormone relationships were appropriate. After parenteral fat free nutrition (primary caloric source glucose) the plasma glucagon levels were significantly lower and the growth hormone levels significantly higher than after the fat emulsion therapy period. The Dudrick and Intralipid methods resulted in a higher caloric intake and weight gain than the Babson method. The former two regimens cannot be completely endorsed, however, since septic and central vein complications are unavoidable with the Dudrick method particularly in the small infant; and the long term effects of intralipid, particularly on the liver are still unknown.

Amino Acids↗