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At least 289 records · Page 16Linked to original sources
PubMedDate not supplied

[Biological model of the accelerated aging. I. Dynamics of spontaneous mutation in spermatogenesis in SAM mice (senescence-accelerated mouse)].

We studied the dynamics of age-related cytogenetic changes in the developing male germ cells of mice prone to accelerated senescence (strain SAMP1) and mice resistant to accelerated senescence (strain SAMR1) by counting the spermatogonial and meiotic micronuclei and testing the defects of the spermatozoon head shape. In these animals, the accumulation of germinative mutations has a nonlinear pattern. During the entire ontogenesis of SAMP1 mice, the frequency of circular spermatids with micronuclei corresponded to the level observed upon induced mutagenesis.

Aging↗
PubMedDate not supplied

[Biological model of accelerated senescence. II. Age-related changes in the number of developing male germ cells and Sertoli cells in gonads of senescence-accelerated mice].

It was shown that in immature three- to four-week-old mice prone to accelerated senescence (SAMP1 strain), the number of spermatogonia, pachytene spermatocytes, and circular spermatids exceeded that in mice resistant to accelerated senescence (SAMR1 strain) by more than two times. Differences were found in the pattern of age-related changes in the number of meiotic and postmeiotic cells in the sexually mature SAMP1 and SAMR1 mice. In the gonads of SAMP1 and SAMR1 mice, the number of Sertoli cells was unstable.

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PubMedDate not supplied

[A biological model of accelerated aging. III. Histological characteristics of age-related changes of spermatogenic epithelium in mice SAM (senescence-accelerated mouse)].

The data characterizing the age-related morphological changes in the spermatogenic epithelium of SAMP1 (senescence-accelerated prone) and SDAMR1 (senescence-accelerated resistant) mice are presented. In many tubules, "early spermatogenesis" was accompanied by the formation of many morphologically abnormal germ cells on histological sections of the gonads of sexually immature (three-four weeks) mice of both strains. At this stage, destructive processes in the spermatogenic epithelium were more pronounced in SAMR1 mice. In sexually mature (two-three months) SAMP1 and SAMR1 mice, spermatogenesis as a whole proceeded normally. The first signs of regressive changes in the inner structure of most tubules (disintegration, detachment of spermatogenic epithelium from basal membrane) and morphology of germ cells (pycnosis, nuclear and cytoplasmic vacuolization) were found in SAMP1 mice at the age of six-seven months. In the older age groups (9-10 and 12-15 months), all types of spermatogenic cells were represented in both SAMP1 and SAMR1 mice, but most of these cells were atypical. Mitotic figures were recorded in a population of highly differentiated Sertoli cells.

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PubMed2002

[Biological model for detection of food antigens].

Antigenic macromolecules present in food can induce inflammatory allergic reaction in sensitized persons. The aim of the present work is the development of an animal model to detect food antigens based on hypersensitivity reaction after food ingestion. New Zealand rabbits were divided in 5 groups. Group 1 (GI): control. G2: Ovalbumin (OVA) sensitized. G3: sensitized and orally challenged with OVA. G4: OVA sensitized and phosphate buffer solution challenged (PBS). G5: sensitized and challenged with OVA. Samples from cecum were stained with Alcian Blue pH < 1 for mast cells and with silver method for enteroendocrine cells (EEC). Other samples were immunostained with anti CD5 and CD25 monoclonal antibodies. Specific IgE levels were detected by PCA. Histopathology of G5 showed patchy edema, lymphangiectasia and eosinophilic infiltration. Results were expressed as cells per HPF (high power field); Mast cells in G1: 1.33; G2: 12.80 and G5: 10.20. Enteroendocrine cells in surface epithelium: G1: 1.6; G2: 6.0; G5: 4.2 and in deep epithelium: G1: 3.0; G2: 12.0 and G5: 7.3. Lymphocytes CD5+ in G1: 24.21: G2: 22.12 and G5: 23.97 and CD25+ in G1: 12.10: G2: 14.30 and G5: 21.68. Group 3 were similar to G1 and G4 to G2. We observed: mast cells increased in number probably due to OVA induced response. EEC showed an increase in sensitized animals because of higher expression of cytoplasmatic granules or differentiation from stem cells. Decrease in EEC number in challenged groups was likely to be based on vesicles release. Total T cells showed no significant differences among groups. CD 25+ cells were higher in sensitized and challenged animals. We concluded that rabbit model of sensitization and oral challenge is valid to study ingested food antigens and potential digestive pathologic reactions.

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PubMedDate not supplied

[Clinical course and phenotypic instability in 4 cases of multiple myeloma: a biological model of tumors].

Four cases of multiple myeloma (MM) are reported in which the coexistence and/or the alternance of different plasma cell clones were observed. Genetic instability is typical of all tumors but in MM it is particularly striking due to the M component marker. In this respect, malignancies reveal the presence of an unremitting competition of different cell populations for the phenotype prevalence. When this phenomenon is related to the clinical picture it is possible, as in our cases, to ascertain that the appearance of new clones often corresponds to significant changes in the disease evolution.

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