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51.
When rats were depleted of copper by administration of a copperdeficient diet, no abnormalities developed in dermal collagen. In contrast, marked changes were produced by penicillamine although the degree of copperdeficiency induced by the drug was less. Large additions of copper to the diet failed to prevent the penicillamine-induced collagen defect when the drug was given parenterally. The effect of penicillamine on soft-tissue collagen appears to be unrelated to its copper-chelating properties.  相似文献   
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Family planning and public policy: who is misleading whom?   总被引:1,自引:0,他引:1  
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Biologically active chorionic gonadotropin: synthesis by the human fetus   总被引:1,自引:0,他引:1  
The kidney, and to a slight extent the liver, of human fetuses were found to synthesize and secrete the alpha subunit common to glycoprotein hormones. Fetal lung and muscle did not synthesize this protein. Since fetal kidney and liver were previously found to synthesize beta chorionic gonadotropin, their ability to synthesize bioactive chorionic gonadotropin was also determined. The newly synthesized hormone bound to mouse Leydig cells and elicited a biological response: namely, the synthesis of testosterone. These results suggest that the human fetus may participate in metabolic homeostasis during its development.  相似文献   
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A pheromone biosynthesis activating neuropeptide (PBAN) hormone that controls sex pheromone production in female moths was identified from the brain-subesophageal ganglion complexes of the adult corn earworm, Heliothis zea. PBAN has 33 amino acid residues and a molecular weight of 3900. Its amino acid sequence has no significant homology with any of the fully characterized peptide hormones. The synthetic peptide, at a dose of between 2 and 4 picomoles, induced production of a normal quantity of sex pheromone in ligated H. zea females. The peptide also induced pheromone production in six other species of moths, thus indicating that this or similar peptides may be responsible for the regulation of pheromone production in moths.  相似文献   
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Surveyor v     
Surveyor V has provided the first direct chemical analysis of the lunar surface. In addition, the amount of ferromagnetic material was measured. More than 18,000 television pictures were taken, and a variety of scientific data were obtained.  相似文献   
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Medical records of 55 dogs with a diagnosis of cutaneous mast cell tumour were reviewed. Twenty-seven of the dogs were treated with surgery plus deionised water and the remaining 28 with surgery alone. A survival analysis was performed to determine whether deionised water, as an adjunct to surgery for cutaneous mast cell tumour, affected survival time or time to tumour recurrence. Dogs in which mast cell tumour recurred had a significantly shorter survival time compared with dogs with no recurrence (P=0.05), regardless of the method of treatment. A significant negative association between tumour recurrence and method of treatment (P=0.0097) and clinical stage (P=0.0223) was observed. Dogs treated with surgery and deionised water had a significantly shorter time to recurrence of their mast cell tumour (P=0.0113). Based on these results, deionised water does not appear to be beneficial in prolonging survival time or time to tumour recurrence for dogs with cutaneous mast cell tumours.  相似文献   
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