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Results for “Specific Pathogen-Free Organisms”

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At least 55 records · Page 3Linked to original sources
PubMed1975

[Histogenesis of the immune system of the "nude" mouse. III. Postnatal development of lymph nodes and spleen: a light microscopical study (author's transl)].

UNLABELLED: In neonatally thymectomized mice, the intermediate cortical zones of the lymph nodes as well as the central portions of the spleen follicles (=thymus dependent areas, TDA) are depleted of lymphocytes within a few weeks (Parrott et al., 1966). The TDA's in the lymphatic tissues of mice homozygous for the gene "nude" (nu/nu) contain also a very small number of lymphocytes. Since only a few developmental stages of the lymphatic tissues in nude mice have been studied, an investigation of the postnatal differentiation of their lymph nodes and spleen seemed worthwhile. MATERIALS AND METHODS: The mice (BALB/c) were maintained under specific pathogen-free (spf) conditions. Heterozygous (nu/ plus) females were mated with homozygous (nu/nu) males in order to obtain the homo- and heterozygous offsprings used in this study. Two nu/nu and two nu/ plus female mice were sacrificed at the following postnatal stages: day 1, 7, 14, 21, 35, 42, 49, 63 and 84, respectively. Newborn and 7 day old mice were fixed in toto in Bouin's solution and embedded in paraffin. From the other animals, spleen and mesenteric lymph nodes were removed and processed in an identical manner. Serial sections were cut at 5 mum and stained with hematoxylin and eosin. RESULTS: The mesenteric lymph nodes of the nu/ plus mice studied were indistinguishable from those of other mouse strains. In the nu/nu mouse, outer cortex and medulla of the mesenteric lymph nodes were found to develop as in normal (nu/ plus) animals, while the intermediate and deep cortex underwent characteristic changes...

Animals↗
PubMed1975

Brain and spinal cord lesions in pigs inoculated with swine vesicular disease (UKG strain) virus and coxsackievirus B5.

Pigs inoculated intravenously with swine vesicular disease virus (UKG strain), those inoculated with coxsackievirus B5, and other pigs exposed by pen contact to the same viruses developed diffuse encephalomyelitis. Perivascular cuffing, with lymphocytes and formation of neuroglia cell foci, were most prominent in telencephalon, diencephalon, and mesencephalon. Encephalitis was of mild to severe intensity. Severity of lesions was more extensive and severe in the pigs exposed to swine vesicular disease virus. Pen contact exposure to either of the 2 viruses caused a more severe central nervous system reaction than did intravenous inoculation. The type and the distribution of lesions produced by the 2 viruses indicate that they may be related.

Animals↗
PubMedDate not supplied

Using the HmL1 strain of Histomonas meleagridis in evaluating chemotherapeutants in chicks.

Ten-day-old White Leghorn cockerels were inoculated per cloaca with 500,000 culture forms of the HmL1 strain of Histomonas meleagridis. Birds dying on the 6th and 7th days and birds necropsied 7 days postinoculation had prominent cecal and liver lesions indicative of severe histomoniasis. Dose responses were obtained with three 1,2-disubstituted 5-nitroimidazoles blended into the feed at various concentrations, demonstrating the utility of this virulent strain in chemotherapy studies.

Animals↗
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

Scanning electron microscopy of the lesions of swine dysentery.

Thirty weanling pigs were examined by scanning electron microscopy at various time intervals after oral inoculation with crude colon contents from pigs affected with dysentery. The earliest recognizable change was a corrugated appearance of the mucosal surface of the large intestine. Large spirochetes, morphologically similar to Treponema hyodysenteriae, were first observed within the crypts of Lieberkühn where they seemed to proliferate onto the luminal surface. Then mucus, fibrin, erythrocytes, and disrupted epithelium appeared. Large spirochetes were always abundant in those lesions, but variable numbers of other mixed bacterial forms were also present. The earliest changes could be correlated with the appearance of large spirochetes in the feces and with early clinical signs, but not with a specific postinoculation time. Once bloody diarrhea was present, no consistent pattern was observed in development, location, or form of the lesions. With time, the lesions merely came to involve an increasingly greater surface area of the large intestine.

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↗
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↗