Morphological and Functional Peculiarities of Lymphoid Cells in Mice of Different Strains

We revealed differences in quantitative composition and functional activity of lymphoid cells in intact mice of different strains. Cellularity and counts of lymphoid elements in hemopoietic and lymphoid organs, proliferative activity of T and B lymphocytes, and counts of CD4+ and CD8+ lymphocytes in the spleen were minimum in CC57W and Balb/c mice and maximum in CBA/CaLac and DBA/2 mice. The highest absolute content of lymphoid elements in the spleen was detected in Balb/c mice, while CC57W mice had the highest content of these elements in the thymus.     

An enzyme immunoassay for identification and quantification of infectious murine parvovirus in cultured cells

An enzyme immunoassay was developed to identify and quantify infectious murine parvovirus. The assay was as sensitive as the fluorescent focus test for quantification of virus in clinical material and was less labor-intensive. Viral infectivity could be inactivated with formalin prior to performance of the enzyme immunoassay. Specificity of the reaction product was shown by neutralization of infectivity using a hyperimmune rabbit antiserum to murine parvovirus.     

Prophylaxis of tumors induced by carcinogens in inbred mice

Antitumor vaccines were obtained with the aid of a filtrate of the culture fluid after growth of a culture ofBacillus mesentericus AB-56 from the cells of a sarcoma K-239 induced by methylcholanthrene and of an undifferentiated sarcoma Rt induced by an extract of the plantRubia tinctorum. Immunization of inbred CBA mice and CBAxC57BL/j hybrids with the vaccines led to resistance to subsequent inoculation with the same tumors in 84–100% of cases. The effectiveness of vaccination depended on the time elapsing since the vaccine was prepared and on the quantity of vaccine material taken for testing postvaccinal immunity.Academician D. K. Zabolotnyi Institute of Microbiology and Virology, Academy of Sciences of the Ukrainian SSR, Kiev. (Presented by Academician of the Academy of Medical Sciences of the USSR, L. V. Gromashevskii.) Translated from Byulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 78, No. 9, pp. 90–92, September, 1974.     

Reversal of phenobarbital-induced hyperplasia and hypertrophy in the livers of lpr mice

Fas is a cell surface receptor that mediates apoptosis, and Fas mRNA has been demonstrated in hepatocytes. MRL/MP - lpr/lpr mice carry the mutated lymphoproliferation-associated gene, lpr , that codes for truncated Fas protein, resulting in reduced apoptotic potential in some circumstances. Phenobarbital treatment of experimental animals induces cytochrome P450 enzymes, and thus acts as a growth stimulus to the liver with both hyperplasia and hypertrophy; cessation results in reversion of liver to normal size with apoptosis playing a role. This study has determined the respective contributions of atrophy and apoptosis to this involution in Fas-defective and normal-Fas bearing animals. Between the first day and the fifth day after phenobarbital cessation, the weights of both Fas-defective ( lpr/lpr  ) livers and control ( lpr  /+) livers reduced. Hepatocyte hypertrophy gradually reverted in both categories of mouse and this was the greater contribution to reduction in liver size. In lpr/lpr animals, there was a consistent level of apoptosis which remained relatively constant, while numbers of apoptotic cells in control livers increased over the period. This investigation has shown that in liver, a mechanism to execute apoptosis is operative even in Fas-defective mice, but it is not sensitive to signals activated by the removal of the growth stimulus. This is in contrast to mice which can mount a Fas-mediated response; thus a separate apoptotic pathway is indicated.     

Level and shape of sequences of motor behavior in inbred and hybrid mice

Three-hundred seventy-five mice of six inbred strains and their F₁ hybrid crosses were observed in a barrier apparatus. Frequencies of jumping over barriers were recorded at each of ten 30-sec intervals. Graphs plotted of mean jumps at each time point show several F₁ curves with an apparently adaptive pattern: low frequencies of jumps at start, gradually rising, then leveling off. Nine out of 15 F₁ curves also show evidence of heterosis: jumping frequencies of hybrids exceed those of parent strains. Lack of heterosis was peculiar to crosses in which C57BL/6 was one of the parents. A coefficient of convexity C was developed to quantify the shapes of the temporal patterns of proportions of animals engaged in jumping at a given point in the sequence. F₁ curves (unlike inbred strains) were found, on the whole, to be negatively convex.This work was supported by a grant from the Faculty of Social Sciences of The Hebrew University.     

Are paw preference differences in HI and LO mice the result of specific genes or of heterosis and fluctuating asymmetry?

Collins (1985) has described two separate mouse strains, obtained by selective breeding, which differ in having high (HI) or low (LO) degrees of paw preference on a standard test. In this paper I argue that the differences between these strains may not be due to a specific gene (or genes) but, instead, probably reflect differences in the total heterozygosity of the strains, such that the HI strain is more heterotic than the LO strain. Greater degrees of heterozygosity are argued to buffer against fluctuating asymmetry and hence result in a greater degree of paw preference.Preparation of the revised version of this paper took place while I.C.M. was in receipt of a Commonwealth Fellowship at the University of Waterloo, Ontario, Canada.     

The progression of behavioral and pathological effects of the parasite Toxocara canis in the mouse

Toxocara canis, the parasitic roundworm of the dog may infect aberrant hosts including mice and humans. The present study examined the behavioral and pathological changes at each of three postintubation periods (Period 1: 8-10 days, 2: 49-51 days, and 3: 84-86 days postintubation, respectively) in independent groups of mice intubated with 1000 eggs of T. canis. Eight-ten days after intubation Toxocara infected animals typically showed depressed levels of activity relative to saline-intubated controls. The scope and severity of behavioral changes were attenuated when different mice were tested 49-51 days after infection, and then became more severe when the third set of animals was tested 84-86 days after intubation. While brain pathology increased over the three periods, visceral organs showed marked pathology 8-10 days after intubation followed by a decrease in severity. These data suggest that Toxocara associated pathological changes in visceral organs and in the brain have behavioral consequences in mice. Given the similarity in migratory pathways of this parasite in rodents and humans, and the findings of T. canis larvae in human brain tissue, the results of this animal study may have implications concerning the possible etiology of behavioral disorders for children who have a known history of pica for dirt.     

Proliferative potential of CFUs from bone marrow of thymectomized mice

All-Union Hematologic Scientific Center, Ministry of Health of Russia, Moscow. (Presented by Academician of the Russian Academy of Medical Sciences A. I. Vorob'ev.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 114, No. 8, pp. 208–209, August, 1992.     

Investigation of autonomy of action of the white gene in allophenic mice

An allophenic mouse and three allophenic embryos were obtained by fusion of eight-cell Mi^wh/Mi^wh and +/+ embryos. The color of the hair and pigmented epithelium of the eye showed chimerism. The Mi^wh/Mi^wh melanoblasts die during development of the embryo. Variations in color of the chimera depend on interaction between normal melanocytes and the surrounding cells of the dermis, which consists of clones with the Mi^wh/Mi^wh or +/+ genotype and a mixture of cells of these genotypes. Differences were observed in the development of the right (chimeric) and left (normal) eyes and normal clones grew more rapidly in the allophenic mouse. Pigmentation of the eyes was reduced in the two allophenic embryos compared with normal. This indicates the autonomous action of the white gene in mice.Laboratory of Experimental Genetics, Institute of Medical Genetics, Academy of Medical Sciences of the USSR, Moscow. (Presented by Academician of the Academy of Medical Sciences of the USSR A. P. Avtsyn.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 85, No. 3, pp. 365–368, March, 1978.     

Comparative studies between nude and scid mice on the growth and metastatic behavior of xenografted human tumors

The growth and metastatic behavior of three human tumor cell lines and a human colon carcinoma previously passagedin vivo were compared between nude mice and scid mice after xenotransplantation. The three human tumor lines included a bladder carcinoma (T24B), a melanoma (RPMI 7931) and alacZ gene-transduced breast cancer (MDA-MB-435 BAG). ThelacZ gene codes for -galactosidase, which can be stained blue with chromogenic substrate X-gal, thus allowing the highly sensitive detection and quantitative examination of human cancer metastasis in host mice. Adult (7–14 weeks) NMRI nude and C.B-17 SCID mice were inoculated with 0.5–5 × 10⁶ tumor cells s.c. Comparable take rate, latent period and growth rate of implanted tumors were observed in nude and scid mice for each of the cell lines tested. At the time of autopsy, which varied from 6 to 11 weeks after inoculation, a significantly higher incidence of spontaneous lung metastasis was discovered in scid mice (96%) than in age-matched nude mice (27%, totalP < 0.001).In vitro assays for NK cell-mediated cytotoxicity revealed no significant differences between the two strains of mice. Our results suggest that nude and scid mice are equally suitable for propagating human tumors. However, the metastatic capacity of human tumor cells appears to be better expressed in scid mice. Scid mice may therefore provide an advantageous model for the study of human tumor metastasis.     

Functional Activity of the Adrenal Cortex in Mice of Opposite Strains with Candidiasis

Experiments were performed on two opposite strains of mice differing in the basal blood glucocorticoid concentration in the blood. Infection of animals with C. albicans fungi led to the development of hypocorticism. C57Bl/6 and CBA mice with progressive candidiasis showed a persistent and phasic course of hypocorticism, respectively. __________ Translated from Byulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 140, No. 9, pp. 279–281, September, 2005     

Response of Mononuclear Phagocyte System to Experimental Tuberculosis in Mice of Opposite Strains

Genetically determined peculiarities of the reaction of the mononuclear phagocyte system to BCG vaccine manifested in CBA and C57Bl/6 mice by differences in the number and size of granulomas and time course of changes in the cellular composition of granulomas, peripheral blood, and bone marrow. __________ Translated from Byulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 140, No. 8, pp. 227–230, August, 2005