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At least 91 records · Page 5Linked to original sources
PubMed1975

[Local Schwartzman phenomenon in axenic rabbits].

Local Schwartzman phenomenon was produced by coli-endotoxin in all the germfree rabbits tested (11 in all) at the age of 102 to 135 days. Any kinds of natural antibodies were not detected in sera of the rabbits, which in fact were found to be agammaglobulinaemic in most cases, as revealed by immunoelectrophoresis. These facts suggested that the germfree rabbits utilized here had not been sensitized to bacterial endotoxins. From the results obtained here, it may be concluded that the existence of hypersensitivity to endotoxin is not necessary to the production of local Schwartzman phenomenon by bacterial endotoxin.

Animals↗
PubMed1975

Adjuvancy of streptococcal nucleic acids.

A study was performed to find out whether or not RNA and DNA isolated from Group A streptococcal cytoplasm does possess adjuvant activity. The findings obtained indicate that the adjuvancy of streptococcal RNA is very similar to that of poly I:C. The adjuvant activity of poly I:C is characterized by its capacity to increase the number of pre-existing hemolysin-producing spleen cells and by its ability to increase the development of 19S and 7S producers early in the 12-day-period of primary immune response. The adjuvancy of streptococcal DNA was considerably less pronounced than that of RNA. Neither poly I:C nor streptococcal RNA and DNA were found to be capable of increasing the process of priming for the secondary immune response.

Adjuvants, Immunologic↗
PubMed1976

Embryo transfer in pigs: a method for introducing genetic material into primary specific-pathogen-free herds.

Fifty-five embryos were transferred from 4 Duroc donor sows into 4 crossbred recipient gilts. The embryo survival rate was 66%; 53% of eggs ovulated by donors were represented by live pigs at term. Three of the litters were obtained by hysterectomy of the recipients and introduced into a primary specific-pathogen-free herd, thereby saving the donor sows for subsequent use. Embryo transfer provided a method for exploiting the genetic potential of superior females.

Animals↗
PubMed1976

Trypsin and chymotrypsin activity of the intestinal content in germfree, monoassociated and conventional rabbits.

Trypsin (T) and chymotrypsin (CHT) activities in luminal contents of the ileum, caecum and sigmoideum were followed in conventional (6 animals), monoassociated (5) and germfree (5) rabbits by pH-stat automatic titration using p-toluenesulphonyl-L-arginine methylester and acetyl-L-tyrosine ethylester as substrates. In conventional rabbits with complete microbial flora an aborally increasing decline of both proteolytic activities of luminal contents was determined (ileum T 198.2 - CHT 100.0; signmoideum T 10m.2 - CHT 68.8 mrg/g of intestinal content). Monoassociated animals represent a group different from both germfree and conventional animals. Trypsin and chymotrypsin of intestinal contents were not significantly altered by the presence of megacaecum in germfree rabbits (ileum T 219.2 - CHT 160.2; sigmoideum T 208.8 - CHT 110.8 mug/g of intestinal content). Chymotrypsin in the intestinal contents appears more labile and more affected by microbial flora than trypsin.

Animals↗
PubMed1976

Some data on establishing a specific-pathogen-free guinea pig colony.

Detailed procedures for the germfree delivery of guinea pigs using a "dry hysterectomy" technic were given; 320 animals were alive after hysterectomy, but there was a subsequent loss of 37% of the animals, mainly during the first and second weeks. Their specific-pathogen-free maintenance, feeding, and association with an anerobic flora were described. Feeding 3 times a day vs twice a day decreased mortality from 48% to 20%.

Animal Feed↗
PubMedDate not supplied

Heterogeneity of mouse B lymphocytes: studies using in vitro response to lipopolysaccharide.

When murine lymphoid cells from spleen and lymph nodes were cultured with LPS, all the transformed blasts observed were B cells bearing surface IgM which could be classified into two types depending upon whether they contained intracellular IgM (i mu +) or not (i mu -). At the ultrastructural level, the two categories of blasts appeared to correspond to cells having a well-developed ER or primarily free ribosomes. A striking observation was that the proportion of i mu + blasts among transformed cells was 5-10 times lower in cultures of lymph node than in cultures of spleen cells. The same observations were made on LPS cultures of "purified" B lymphocytes. Prolongation of the culture period did not modify these results. This indicated that the differences in the response to LPS reflected the existence of at least two pre-existing subpopulations of B cells unequally distributed in peripheral lymphoid organs. Analysis of the surface antigens and receptors (MBLA, surface Ig classes, Fc and C receptors) of the B cells from spleen and lymph nodes did show some differences between these two lymphoid organs. Among the transformed cells, Fc receptors were present mainly on i mu - cells and C receptors on i mu + cells; however, no strict correlation could be made between the i mu + or i mu - nature of these cells and their surface characteristics. The possibility that precursors of i mu + and i mu - blasts might represent virgin and memory B cells or B cell populations differing in their requirement for helper factors released by stimulated T cells was explored by using cultures of spleen and lymph node cells (1) obtained from germ-free mice, which are expected to have few memory cells, or (2) performed in the presence of the supernatant of mixed lymphocyte cultures, in conditions where these supernatants are known to contain factors released by activated T cells. Neither condition modified the degree of transformation or Ig content of blasts.

Animals↗
PubMed1975

[Comparative morphometric data on the epiphysis, the subfornical organ, and the anterior pituitary gland in 2 groups of pure strain Wistar female rats, SPF or conventional].

In SPF female rats, the pineal gland is less voluminous and its cell-nuclei are smaller than those of conventionnal female rats. This confirms (with the voluminous adrenals previously reported) the stressing action of the absence of pathogenic germs on these animals. The anterior lobe of the hypophysis is slightly smaller and subfornical organ a little larger than in conventionnal female rats.

Animals↗
PubMed1976

The experimental infection of specific pathogen free lambs with Mycoplasma ovipneumoniae.

Six colostrum-deprived SPF lambs inoculated endobronchially with a second passage broth culture of a Scottish strain of Mycoplasma ovipneumoniae, were killed in batches of two at seven, 14 and 28 days post-inoculation. One lamb from each batch showed macroscopic and microscopic lung lesions similar to but milder than those described for respiratory mycoplasmoses in other species of animals and exhibited minor clinical symptoms. Mycoplasma were recovered from all infected but from no control animals: five infected lambs yielded mycoplasma from lung tissue. Two lambs infected with M ovipneumoniae by endobronchial intubation were placed in contact with six other SPF lambs. M ovipneumoniae was recovered from the upper respiratory tract only of all six contact lambs, but no pathological changes were noted in their lungs. Both donor lambs yielded mycoplasma from lung tissue, but microscopic lesions were detected in only one of them, and these were minimal. No seroconversion due to the infection could be demonstrated in any of the lambs by either the indirect haemagglutination or metabolic inhibition tests.

Animals↗