Effects of Arginine Vasopressin on Renal Function in the Rabbit

It has long been known that Vasopressin could increase the urinary sodium and chloride excretion. The exact mechanism and site of action, however, have not yet been explained. Experiments were performed whether the renal effects were the same in both cortical and juxtamedullary nephron in decorticated kiddney model. Heat-decortication was car ried out in the left kidney immersed in water kept at 52oC for 5 minutes. In 90% of cases, outer 2/3 of the cortex was necrotized as revealedd at the time of experiment on 8th day. The right kidney underwent the same procedure except that the temperature of water was kept at 39oC, and served as control. Urine flow and fractional excretion of urine were increased by the arginine vasopressin infusion in both kidney, but the diffferences were not significant. There were no signifficant changes in glomerular filtration rate and rrenal plasma flow in doses of 5 and 10 mu/kg/minute. Responsiveness of decorticated kidney was less than the control kidney. Increments of fractional excretion of potassium were not significantly different. From thhese results, it is suggested that the responsiveness of the cortical and juxtamedullarry nephron to the arginine vasopressin may not be the same. The mechanisms of the differences were discussed.

Hemagglutination and Drug Resistance of Escherichia coli Isolated from Children

A hemagglutination(HA)-typing system has been developed for the presumptive identification of enterotoxigenic Escherichia coli(ETEC) possessing the colonization factor antigens(CFA) Seventy-seven E. coli strains from pediatric patients with or without diarrhea were examined for the mannose-resistant(MR) HA or mannose-sensitive(MS) HA of human, bovine, chicken, and guinea pig erythrocytes and their antibiotic resestances. A significant proportion(68%) of the isolates exhibited the HA pattern of NNNN(experssed in the order human/bovin/chicken/guinea pig erythrocytes), and 10% of the isolates exhibited NNSS, known as the pattern about half of enteropathogenic E. coli serogroups produced. Sixty-nine strains(88%) were resistant to one or more antibiotics; 55(80%) were reristant to four or more antibiotics. The strains showed multiple drug resistance were more higher in HA-positive strains(92% of HA-positive strains) than in HA-negative strains(76% of HA-negative strains) and all of the HA-positive strains with human erythrocytes were resistant to 4 or more antibiotics. There were no significant differences between HA patterns and antibiotic resistance in both the strains from the patients with or without diarrhea. In summary, although the causative organisms in cases of diarrhea of this study have not been established, the date herein suggested that ETEC possessing CFA which produce RRRN or NRRN HA pattern was not participated in this diarrhea.