Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Germ-Free Life”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 73 records · Page 4Linked to original sources
PubMed1975

Electrical resistance and ATPase levels in the cecal wall of germ free and conventional rats.

(a) Electrical resistance across the cecal wall of germfree rats is higher than in conventional controls when the luminal fluid is a physiological solution. Transmural resistance of the cecum increases both in germfree and conventional rats when the supernatant from cecal contents of germfree rats is used as luminal fluid. These phenomena might be due to an effect of germfree intestinal contents on the ionic composition and/or on the dimensions of intercellular pathways within the intestinal epithelium. (b) Total and Na+ and K+ stimulated ATPase show higher levels in mucosal scrapings from the ileum and cecum of germfree rats than in conventional controls. This characteristic of the germ-free lower bowel may be associated with the greater "absorptive efficiency" which it was found to display when relieved from luminal inhibitory substances.

Adenosine Triphosphatases↗
PubMed1976

The size pH, and redox potential of the cecum in mice associated with various microbial floras.

Cecal size and in situ redox potential and pH of cecal contents were determined in conventionally reared mice and mice reared under a variety of gnotobiotic conditions: germfree, monoassociated with a cecal Clostridium sp., hexaflora-associated and thermoduric polyflora-associated. The mean Eh was approximately +200 mV in germfree and -200 mV in conventional mice. The Eh was close to zero in the monoassociated mice, thus occupying a position intermediate between the germfree and conventional mice. The potentials observed in the hexaflora and the thermoduric flora groups were indistinguishable from those of conventional animals. The degree of normalization was more advanced with respect to the redox potential than to the cecal size in the various gnotobiotic groups. In the thermoduric polyflora-associated group, normalization was observed in both cecal size and redox potential. This demonstrates that normalization can be accomplished with a relatively simplified microflora, at least with regard to the parameters studied.

Animals↗
PubMed1978

[Distribution of Pseudomonas aeruginosa in experimentally infected mice (author's transl)].

The distribution of experimentally administered Pseudomonas aeruginosa was studied in germfree CF no. 1 mice, barrier-sustained DDD mice with or without oral treatment of aminobenzyl-penicillin and conventional DDD mice. On day 1 after oral administration of 8 X 10(7) organisms, more than 10(8) of organisms/g were recovered from the feces of ex-germfree mice and the number was maintained during the experiment. On the other hand, from barrier-sustained mice with antibiotic treatment and those without the treatment, 10(4-7) and 10(3) organisms were recovered, respectively. In all of monoassociated mice and some antibiotic-treated barrier-sustained ones the organisms were recovered also from the lungs, liver, spleen and kidneys. In conventional mice, however, no organisms were recovered from the internal organs throughout the experiment, while some were detectable from the intestinal tracts. The distribution of the organisms in naturally infected mice appears to be similar to that of experimentally infected animals with antibiotics.

Ampicillin↗
PubMedDate not supplied

Control of intestinal flora in animals and humans: implications for toxicology and health.

The importance of the intestinal flora in disease management is discussed, and apparent relationships noted in experimental and clinical reports are reviewed. It is suggested that investigation of the influence of the intestinal flora upon body organs and systems would productively lay the groundwork for abetter understanding of certain synergistic mechanisms.

Animals↗
PubMed1978

[Microbial contamination of dust in minimum-morbidity housings for pig rearing].

The range of the microbial contamination of 1 g of dust in minimum-morbidity pig rearing houses is from 2.9 . 10(7) to 7.6 . 10(9) in the microbes growing on meat-peptone agar (MPA), from 4.6 . 10(7) to 4.6 . 10(8) in moulds growing on the Czapek-Dox agar, from 1.4 . 10(2) to 7.0 . 10(4) in the total number of microbes growing on End's agar, and from 3.1 . 10(2) to 5.7 . 10(3) in the typically lactose-positive microbes growing on End's agar. The numbers of microbes in 1 g of dust in the conventional pig houses are close to the numbers found in pig rearing houses with minimum morbidity. However, in the moulds on the Czapek-Dox agar, the range of the microbial contamination of dust in the minimum-morbidity pig houses was much higher. The highest level of the contamination of dust with microbes was found on all types of media from houses with continual operation. It was revealed by the control of the effectiveness of disinfection in the minimum-morbidity piglet rearing section, operated on the all-in all-out basis, that in a half of the cases studied the disinfection had low effectiveness. The total number of microbes per 1 sq. cm was lower than required on the basis of research published in literature, but the occurrence rate of positive smears with lactose-positive microbes after disinfection was higher in percentual expression.

Animals↗
PubMedDate not supplied

Morphology and enzyme aktivity in rat small intestinal epithelium 6 and 12 hrs. after an alkylating agent (cyclophosphamide).

Six and twelve hours after a single i.p. dose of cyclophosphamide (100 mg/kg body weight) the activity of different "brush border enzymes" (maltase, sucrase lactase, alkaline phosphatase, gamma-glutamyl transferase) and of a lysosomal enzyme (acid phosphatase) did not change. In vivo absorption of galactose was not diminished by the treatment. The pattern of response to cyclophosphamide seems to be different in SPF and GF rats. The response of crypt epithelium (cell number, mitotic number, mitotic frequency) was more pronounced in the SPF rats, whereas the villus height only decreased in the GF rats.

Alkaline Phosphatase↗
PubMed1979

[Stimulation of proliferation of rat spleen cells, in vitro, by a nonspecific acute inflammatory exudate. Modulation of cell response to phytohemagglutinin (PHA)].

The effect of an acute non-specific inflammatory exudate with mitogenic activity on macrophages in culture has been tested on the spontaneous and PHA-induced DNA synthesis of spleen cells in vitro. Stimulatory effect of this exudate was observed on spontaneous DNA synthesis which was detectable over a range of 1 : 4 to 1 : 4,000 concentrations. After optimal PHA stimulation, an inhibition of mitogen-induced DNA synthesis was observed when the cells were exposed to the highest concentrations (up to 1 : 128) of the exudate. Thereafter, the phenomenon could be reversed and the stimulation was maximal at a concentration of 1 : 2,000. When a sub-optimal dose of PHA was used, the simulatory effect was more pronounced and detected from 1 : 8 up to 1 : 4,000 concentrations.

Acute Disease↗
PubMed1979

Induction of suppressor cells in rat spleen: influence of microbial stimulation.

The role of the products of prostaglandin synthetase in the suppression of in vitro secondary antibody responses by rat spleen cells was examined. By including cells from both germfree and conventional rats in these studies, the effect of in vivo microbial stimulation on this suppression was also determined. We found that 1) the suppression that is normally present in the spleen cells of rats can be eliminated by the use of glass wool or indomethacin; 2) germfree rats do not display this suppressor activity, and 3) this "deficit" in the germfree rat may be due to a lack of a microbial-induced signal from a nonadherent cell to an adherent prostaglandin-containing macrophage, implying that at least two cells are involved in the prostaglandin-synthetase dependent suppressor effect. It is possible that large amounts of some or all microbial products activate "suppressor" macrophages and that inbred rats behave like "chronically infected" mice because of an inability to regulate their "normal" microbial flora.

Animals↗
PubMed1975

Mycoplasmosis in specific-pathogen-free and conventional guinea pigs.

Normal female guinea pigs were examined for organisms of the order Mycoplasmatales. Thirty-nine isolations were made from nose or vagina of 108 guinea pigs. Seven isolates were identified as Mycoplasma caviae, 9 were unidentifiable mycoplasmas, and 23 were identified as nonsterol-requiring acholeplasmas.

Animals↗
PubMed1975

[Sulphated glycosaminoglycans as virus inhibitors. 2nd communication: Inhibitory effect of glycosaminoglycanpolysulphates on yellow fever virus 17 D in animal experiments (author's transl)].

Glycosaminoglycanpolysulfates (GAGPS) have virus inhibiting properties demonstrable by means of tissue culture in the plaque method. In brain preparations of children who had died of a hyperpyretic toxicosis, cell necroses were found corresponding to the picture of tissue culture plaques. The question arose from these observations whether this inhibiting effect of GAGPS can perhaps also be demonstrated in vivo. In animal experiments, cell necroses corresponding to those of the infant brain could be observed during the course of a 17 D yellow fever encephalitis in mice. The Luitpoldt-Werk Munich placed to our disposal 13 different GAGPS for tests. Each of these substances was tested in 210 mice (fig. 1). Virus dilutions (LD 50/ml) were mixed to the same volume with the indicated concentrations of substance directly before vaccination. The differing LD 50 doses is due to the fact that each ampoule contains a different content of virus.) The toxicity of all substances is practically zero (table 2a, 2b). The effect of the inhibiting substances was evaluated at first by means of a deviation of the rate between alive and dead animals (table 1). The statistical significance of the effect of some substances was that high so that an inhibition of the virus replication has obviously to be considered. The significance for L1 and L4 - they are chemically very similar - is higher than 0.001 (table 4). The virus inhibiting effect of the substances was controlled by histopathology. 31 brains of mice were dissected and histologically evaluated; the lesions of the brains were examined and recorded (table 3). The effect of the substances was measured by absence or diminution of the lesions. The most effective substance was L1 as far as its concentration was higher than the critical limit of 625 gamma/ml.

Animals↗