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Biomedical subjects

G E Miller

Publications and source records attributed to G E Miller.

At least 73 records · Page 4Linked to original sources
PubMed1976

Attenuation measurements of a fast neutron radiotherapy beam.

Attenuation measurements have been made for pressed wood, steel and lead in the neutron beam generated by 35 MeV deuterons on a thick Be target, using narrow-beam, semibroad-beam and broad-beam geometries. In addition, the measurements were extended to the neutron beams from 25 and 15 MeV D+ on Be, for semibroad-beam geometry only. A tissue-equivalent plastic ionization chamber was used as the detector; hence the measured parameter approximated the total (n + gamma) dose in tissue. After correcting for radiation scattering around the absorbers, the remaining curves were nearly exponential in most cases, and a build-up factor could be employed to describe the varying degree of scattered radiation dose as a function of absorber thickness and geometry. The results given should be applicable in designing primary-beam shields and collimators, as well as providing a useful basis for extending calculations to other geometries through Monte Carlo techniques.

Deuterium↗
PubMed1976

The fate of experimental organ-cultured corneal xenografts.

Human, chicken, and guineapig corneas organ cultured (O.C.) from 1 to 4 weeks were transplanted intralamellarly into rabbits. Chicken and guinea pid corneal xenografts O.C 3 to 4 weeks had statistically significant delayed rejection times reject. Histologically, O.C. xenografts with delayed rejection or nonrejection were hypocellular. Chicken xenografts O.C. 4 weeks in which recipient (autochthonous) rabbit serum replaced the calf serum routinely used in the media also had a significant delay in rejection time when compared to fresh controls or chicken xenografts stored in pooled (allogeneic) rabbit serum. The rejection time of human corneal xenografts O.C. FOR PERIODS UP TO 4 WEEKS WAS NOt delayed. These data suggest that in this model, prolonged survival of xenografts after O.C. is species specific and represents a form of immunological modification, possibly reduced antigenicity sedondary to donor hypocellularity.

Animals↗
PubMed1976

Oxytetracycline in bovine plasma, milk, and urine after intrauterine administration.

Six healthy lactating cows with normal but varying stages of estrous cycles were treated with chelated or nonchelated oxytetracycline by intrauterine infusion, 4 mg/kg body weight. The chelated drug was a mixture of special metal halides and oxytetracycline while the nonchelated form was a commercial oxytetracycline solution suitable for intramuscular or intravenous administration. Oxytetracycline concentrations in plasma, milk, and urine were determined at timed intervals following treatment. Both forms of the drug appeared in the plasma, but the chelated form was a small amount. The nonchelated oxytetracycline also appeared in the milk. However, no oxytetracycline was in milk of cows treated with chelated oxytetracycline. Both forms of the drug were excreted in the urine. Milk should be withheld from market 24 and 0 h after administration of nonchelated and chelated forms.

Animals↗
PubMed1975

Ultrastructure of human organ-cultured cornea. II. Stroma and epithelium.

The stroma and epithelium of human corneas that had been stored in organ culture medium for 10 to 22 days at 37 C were examined by light and electron microscopy. Total corneal thickness was found to be doubled at ten days and there was no further increase even at 22 days. The posterior portion of the stroma was more hydrated than the anterior region. Stromal cells were reduced in number and normal-appearing cells were present only in superficial stroma. The epithelial basement membrane was irregular and thickened. Although the epithelium was reduced to three or four cells in thickness and the intercellular spaces were dilated, the epithelial cells contained normal subcellular organelles and appeared to be viable.

Basement Membrane↗