Animals germ free

Animal studies indicate that the pathogenesis of NSAID small intestinal toxicity involves multiple interactions dependent on enterohepatic circulation, epithelial permeability, neutrophil infiltration and bacterial infection [233]. Several investigations [234-238] have suggested that bacterial flora may play a role in the pathogenesis of NSAID bowel injury and Robert and Asano [239] did show more than 25 years ago that germ-free rats are resis-... 

No growth increase by antibiotics in germ-free animals. 

Antibiotics do not promote growth of sterile, so-called germ-free animals or of chick embryos. This shows that the growth effect is not produced by direct action of antibiotics on animals... 

One particular /3-galactosidase cleaves the compound lactose-lysine into /3-galactose and fructose-lysine. This activity is of interest because it has been suggested as a possible marker for the presence of bacteria, since it does not appear to be present in germ-free animals. 

Bealmer, P.M., Holtermann, O.A., and Mirand, E.A. 1984. Influence of the microflora on the immune response, I General characteristics of the germ-free animal. In The Germ-Free Animal in Biomedical Research (M.E. Coates and B.E. Gustafsson, eds), pp. 335-346. Academic Press, London. 

These knockout mice, if housed in a conventional animal environment, develop splenomegaly, bone marrow myeloid hyperplasia, and lymph node hyperplasia with an increase in neutrophils, B cells, and plasma cells. These phenotypic abnormalities fail to develop in a germ-free environment (Shuster et al,... 

It is the consensus of opinion that normally the fieBh of healthy animals is free from bacteria. Fresh meat from healthy animals, then, if properly handled should be low in germ content. Some authorities believe that there should be bacterial standards for meat while on the other hand there are people who prefer meat in which there are visible signs of protein liquefaction. This subject of the relation of miscellaneous microorganisms to meat needs much further investigation. 

No information is available at present on the effects of the many other secondary bile acids present in feces in small concentrations on water and electrolyte movement in the colon. In addition, no information is available on the role of bile acids in constipation, irritable bowel syndrome, nonspecific diarrhea, antibiotic diarrhea, or the diarrhea of the germ-free animal. Of interest is the response of the diarrhea of the germ-free animal to an anion exchange resin similar to cholestyramine (112). Studies are needed to define the structure-activity relationships for bile acids and the induction of water and sodium secretion by the colon. In addition, information is needed on the composition, concentration, and physical state of bile acids in colonic contents and feces in health and disease. 

Table 6 contains the mean value of three separate experiments. A comparison of the intestinal and peritoneal cell counts reveals that the ampicillin treatment reduced the intestinal cell counts approximately a hundred-fold without affecting the Salmonella titer. Cycasin alone (positive control) resulted in the anticipated rise in MF for typhimurium ampicillin alone did not alter the spontaneous MF, and mice treated with both ampicillin and cycasin were approximately the same as the negative control. The reduction of intestinal microorganisms by ampicillin and the resultant inability to detect mutagenic activity after administration of cycasin parallel the finding in carcinogenic studies. In germ-free animals no tumors were found after administration of cycasin (Spatz et aL, 1967). 

The morphogenetic effect of the intestinal flora becomes evident when the intestinal mucosa of a conventionally reared animal is compared with that of a germ-free animal. In a germ-free animal, the lymphoid tissue of the Peyer s patches is poorly developed the intestinal epithelium remains undifferentiated and resembles the epithelium of the prenatal stages. The intestinal flora synthesizes vitamin K and B group vitamins. 

---