Preliminary evidence of the contribution of the intestinal microflora to biotin supply in zebrafish Danio rerio (Hamilton-Buchanan).

A study was conducted to preliminarily assess the contribution of the intestinal microflora to biotin supply in zebrafish. Biotin and avidin were added to three isonitrogenous and isocaloric purified diets to provide molar avidin: biotin ratios of 0:0 (basal diet), 0:1 (biotin-supplemented diet), and 120:0. Another diet was made by supplementing the antibiotic succinylsulfathiazole (1%, wt/wt) to the basal diet. A fifth diet was the Zeigler commercial diet for zebrafish. Each diet was fed to a triplicate group of fish (mean initial mass 0.266 g) for 8 weeks. The condition factor, feed conversion ratio (FCR), percentage weight gain, and survival were similar in fish groups fed the commercial and the biotin-supplemented diets, but energy conversion efficiency and whole-body biotin content were highest in the fish fed the commercial diet (p<0.05). Reduced growth and survival, and increased FCR were noted in fish fed basal diet compared with those fed biotin-supplemented diet. The supplementation of avidin in diet led to lower survival and condition factor, and higher FCR than that observed with basal diet. Intestinal microbial synthesis is assumed to be a significant source of biotin to the zebrafish, as fish fed the antibiotic-supplemented diet showed the lowest growth, health condition, and feed utilization.

Screening prescription drugs for possible carcinogenicity: eleven to fifteen years of follow-up.

Using computerized pharmacy records from 1969 to 1973 for a cohort of 143,574 members of the Kaiser Permanente Medical Care Program, we have been testing associations of 215 drugs or drug groups with subsequent incidence of cancer at 56 sites. This paper presents findings with follow-up through 1984. There were 227 statistically significant (P less than 0.05, two-tailed) associations: 170 positive, 57 negative. Some were undoubtedly chance findings; others were likely due to confounding by unmeasured covariables. However, several associations suggested hypotheses for further studies and/or the need for continued observation. Most notable among findings not previously reported were associations of several antibiotics, both oral and topical, with lung cancer. These associations could not be explained by indications for drug use or by differences in smoking habits between users and nonusers, and suggest a possible link between the occurrence of bacterial infections and risk for cancer. In general, our results continue to suggest that most medications used during that period did not affect cancer incidence substantially. However, for less frequently prescribed medications, our power to detect moderate increases in cancer risk was quite low.

Death from drug-induced hemolytic anemia.

Fatal hemolytic anemia occurred in a 71-year-old man after trimethoprim-sulfamethoxazole was given for presumed cystitis. Administration of this combination has previously caused multiple hematologic reactions by affecting folic acid metabolism. Megaloblastic anemia and neutropenia have been produced by both of these agents, while sulfamethoxazole alone has induced acute hemolytic anemia in patients with hereditary deficiency of glucose-6-phosphate dehydrogenase. Although hematologic complications of trimethoprim-sulfamethoxazole treatment usually follow long-term or high-dose therapy, acute reactions apparently may occur at lower doses as well.