Three experiments were conducted to determine the effect of certain sex hormones on wool growth in sheep. The administration of estradiol intramuscularly caused a significant (P <.01) reduction in the average weight of clean wool and fibre length obtained from tattooed areas. In addition, this treatment reduced average thyroid weight, but increased pituitary and adrenal weights. It is suggested that the reduction in wool production resulted from a lowered thyroid activity and from adrenal cortical stimulation.The use of diethylstilbestrol orally produced the same general effects as estradiol but to a lesser degree.The administration of a single implant of diethylstilbestrol (12 mg.) to ewe lambs had no effect on wool growth. However, a second implant, administered 3 months after the first, resulted in a significant decrease in the average weight of clean wool from a measured area when compared to the controls.Testosterone significantly (P <.05) increased the weight of clean wool when the sheep were treated with relatively high doses (up to 175 mg.) during the first part of the experiment and lower doses (75 mg.) during the latter part. However, in another experiment where 125 mg. per head was used throughout the trial no response in wool growth was obtained. In the latter experiment there was some indication that thyroid activity was stimulated, suggesting that the testosterone dose was at the lower threshold level for wool growth.Progesterone given intramuscularly had no effect on wool growth in this study.
An in vivo model for correlative imaging studies of intracerebral glial tumors and peritumor brain edema has been developed. Adult male and female cats implanted with 1 x 10(6) or 5 x 10(5) 9L glioma cells had parietal tumors of 4 mm or greater in diameter and showed signs of increased intracranial pressure 13.7 +/- 1.9 days or 19.2 +/- 1.3 days after implantation. No immunosuppression was required and the success rate for tumor growth after implantation was 88%. Histologically, the tumor resembles a malignant astrocytoma. The tumor contained the highest water content (85.94%); peritumor white matter was more edematous (73.01%) than white matter in the contralateral hemisphere (69.04%), sham-operated (69.41%) and control brain (68.76%). There was no correlation between the size of the tumor and water content in tumor or white matter. Increased tissue albumin in peritumor white matter indicated blood-brain barrier dysfunction within the tumor and confirmed the vasogenic origin of the edema. Proton magnetic resonance imaging provided good spatial and contrast resolution with increased signal intensity in edematous white matter, decreasing with distance from the tumor. The large brain of this animal model allows the use of serial imaging and regional correlative biochemical measurements in a single animal. Other advantages of this model are its predictability and the short time required to produce tumors with marked peritumor edema.
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