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Embryonic softshell turtles develop inside eggs exchanging little, if any, liquid water with the nest environment. Despite the consequent restriction on availability of water to support development, embryos convert most of the ammonia released in catabolism of proteins into soluble urea rather than insoluble urate, and thereby commit a portion of their limited reserve of water to serve as solvent for metabolic wastes. This finding is contrary to expectations from prior studies of cleidoic eggs. 相似文献
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Barber SM McLaughlin BG Fretz PB 《The Canadian veterinary journal. La revue veterinaire canadienne》1983,24(2):46-49
A one month old Quarterhorse colt was presented after a week history of bilateral nasal discharge and respiratory difficulty. The cervical esophagus was greatly dilated, tortuous and filled with diluted milk. A nasogastric tube could not be passed beyond the base of the heart. An aspiration pneumonia was found at postmortem examination and the esophageal segment from the pharynx to the base of the heart was dilated, thin-walled, had degenerative muscular changes, and a reduction in size and number of ganglion cells of the myenteric plexus. Muscular hypertrophy of the terminal esophagus had reduced its lumen size. Some similarities and disparities of this condition to achalasia of man and megaesophagus of dogs are discussed. 相似文献
119.
Selenium and glutathione peroxidase levels in lambs receiving feed supplemented with sodium selenite or selenomethionine 总被引:1,自引:0,他引:1
Twenty-one 6 months old female lambs were divided into 7 groups and fed a basal diet containing 0.13 mg Se/kg. The basal diet was further supplemented with 0, 0.1, 0.5 or 1.0 mg Se/kg either as sodium selenite or as selenomethionine, and was fed for 10 weeks. Both feed additives produced an increase in the selenium concentration in the tissues analysed. Significant correlations were found between the concentrations of selenomethionine or sodium selenite added to the feed and the subsequent tissue levels. However, the selenium levels seemed to plateau at approximately 0.5 mg Se/kg of supplemented sodium selenite. The total glutathione peroxidase (GSH-Px) activity of the tissues increased when the selenium supplementation increased from 0 to 0.1 mg/kg for both selenium compounds. With further increase in selenium supplementation the GSH-Px activity in the tissues plateaued except in the blood where the activity continued to rise with increasing selenomethionine supplementation. The selenium dependent GSH-Px activity in the liver rose with increasing selenomethionine supplementation, but approached a plateau when 0.1 mg Se/kg as sodium selenite was added to the feed. The selenium concentration in whole blood responded more rapidly to the selenium supplementation than did GSH-Px activity. The experiment indicates that the optimal selenium concentration in the feed is considerably higher than 0.1 mg Se/kg, and that selenium levels of 1.0 mg/kg in the feed do not result in any risk for the animals or the consumers of the products.Key words: dietary selenium, lambs, selenium concentrations, glutathione peroxidase activities, tissues 相似文献
120.
Knowlen GG Kittleson MD Nachreiner RF Eyster GE 《Journal of the American Veterinary Medical Association》1983,183(9):991-996
The plasma aldosterone concentration (PAC) among clinical status groups of 23 dogs with chronic heart failure was compared at various times after diagnosis of the problem. Eighteen dogs admitted in New York Heart Association (NYHA) class IV clinical status had significant elevations in PAC (P<0.0001), when compared with clinically normal dogs. Five dogs admitted in NYHA class III status and 4 dogs that responded with a change to NYHA class III status had significant elevations in PAC (P<0.01), when compared with clinically normal dogs. In patients with NYHA class IV status, the PAC was significantly greater (P<0.01) than in patients in NYHA class III status. For patients with the poorest prognosis, ie, severe signs of NYHA class IV status, the PAC was not markedly different, when compared with that for patients with a favorable prognosis, ie, recent onset of signs of NYHA class IV status. Patients treated with captopril had significantly lower PAC after therapy (P<0.01), whereas patients treated with hydralazine had significantly higher PAC (P<0.05) after therapy. It was concluded that heart failure in the dog increases PAC, most likely because of renin-angiotensin-aldosterone-system activation, and that the increase is related directly to the clinical status of the patient. Further, it was concluded that treatment of dogs in heart failure with captopril causes a decrease in circulating PAC, whereas treatment with hydralazine causes an increase in circulating PAC. 相似文献