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Biomedical subjects

F A Smith

Publications and source records attributed to F A Smith.

At least 73 records · Page 4Linked to original sources
PubMed1978

Bone mineral turnover in a patient with osteogenesis imperfecta estimated by fluoride excretion.

A child with severe osteogenesis imperfecta was treated with NaF for 8 years, at the end of which time his iliac bone contained 29 mg F/g Ca. Urine F was assayed at intervals for 4.5 years after discontinuing treatment. After the first few days the decline in urinary F excretion can be described by a two component exponential function, with half-times of 5.4 months (10%) and 8.9 years (90%). The latter half-time value is of the same order of magnitude as those observed for F and other "bone-seeking" elements in normal subjects, which suggests that the turnover rate of bone mineral is normal in this disease. Three methods for estimating the attained body F burden at the end of NaF treatment--namely, metabolic balance, bone biopsy, and integration of the exponential function--yielded comparable values.

Bone and Bones↗
PubMed1978

Teratogenic potential of ethanol in mice, rats and rabbits.

Pregnant CF-1 mice, Sprague-Dawley rats and New Zealand white rabbits were given 15% ethanol in their drinking water during the period of major organogenesis, from day 6 through 15 of gestation in mice and rats and days 6 through 18 of gestation in rabbits. Maximum blood alcohol levels, measured in non-pregnant animals, were about 200 mg percent in mice and 25-50 mg percent in rats and rabbits. Maternal toxicity in the form of decreased liquid intake and decreased maternal body weight occurred in all species during the experimental period. A significant increase in the incidence of external or soft tissue alterations was not observed in the alcohol-exposed groups of any species, but a significant increase in minor skeletal variants was observed in mice and rats. These were probably due to retarded fetal growth rather than to a specific effect of the ethanol. Teratogenic effects were not observed in any of the three species.

Animals↗
PubMed1977

Dose and LET distributions due to neutrons and photons emitted from stopped negative pions.

Computer calculations are made of the dose and LET distributions due to neutrons and photons produced when negative pions are stopped in a phantom. When negative pions are stopped in a material they undergo nuclear capture, resulting in the disintegration of the nucleus and the emission of short range charged particles and longer range neutrons and photons. The uncharged radiation constitutes a potentially large source of dose outside the treatment volume. A simple phantom consisting of a 0-25 m cube of either tissue or bone-equivalent material is set up with a 0-05 m cube in the centre to represent the treatment volume. Neutrons and photons are started in this central volume and transported across the phantom using Monte Carlo transport codes. Several different initial energy spectra for the neutrons are used, taken from experimental and theoretical data. These different spectra are found to give significant differences in dose, though the distance to the 80% dose level is always about 0-015 m. Order of magnitude differences in some LET regions are also found. The dose deposited by neutrons in bone is about 24% less than in soft tissue, the photon dose being small compared with the neutron dose.

Elementary Particles↗
PubMed1976

Effects in the liver of methylene chloride inhaled alone and with ethyl alcohol.

When high concentrations of methylene chloride in combination with high concentrations of ethanol were inhaled for one day by guinea pigs, the extent of the hepatic damage induced suggested an antagonism between the effects of the two agents. However, exposure for five days to approximately 500 ppm of methylene chloride plus high concentrations of ethanol suggested ethanol may potentiate the effects of methylene chloride.

Animals↗