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Biomedical subjects

V Portelance

Publications and source records attributed to V Portelance.

6 recordsLinked to original sources
PubMed1979

Protection of cotton rats against experimental Echinococcus multilocularis infections with BCG cell walls.

Previous works has indicated that cotton rats treated with Mycobacterium bovis strain BCG are effectively protected against an infection with the metastatically proliferating metacestodes of Echinococcus multilocularis. In an attempt to induce a similar protection in the absence of tubercular granulomatous lesions, cotton rats were treated with BCG cell walls. A single injection of 150 micrograms of cell walls, emulsified in mineral oil-Tween-saline, 2 weeks before the inoculation of the parasite completely protected the animals against infection with E. multilocularis. This protection was correlated with an increase in the numbers of monocytes and, as judged by acid phosphatase activity, an activation of these cells. This study shows that BCG cell walls are as effective in protecting animals against E. multilocularis as the viable organism.

Animals↗
PubMed1978

Growth retardation and prevention of Ehrlich solid tumor by Clostridium perfringens type A spores and culture supernatant.

When given by direct s.c. injection into the Ehrlich solid carcinoma 1 week after s.c. tumor transfer, viable crude spores of Clostridium perfringens type A (attenuated mutant strain LNG11 ATCC 29348) inhibited tumor growth and significantly prolonged the life span of male outbred Swiss mice. Under these conditions a concentrated sterile supernatant of a C. perfringens culture proved to be slightly more effective than were viable crude spores. In contrast viable crude spores were ineffective in the treatment of female Swiss mice, but the sterile supernatant retained significant activity. When given at the time and site of s.c. grafting of Ehrlich tumor cells, a concentrated sterile supernatant of a C. perfringens culture prevented tumor growth in 80% of male outbred Swiss mice. Under these conditions viable crude spores prevented tumor growth in 70% of mice and significantly prolonged the life span in the other 30%. When given by i.p. injection and before i.p. grafting of tumor cells, viable crude spores of C. perfringens prevented Ehrlich ascites tumor in 5 of 12 Swiss mice and prolonged life span in the other 7. In contrast concentrated sterile supernatant and viable purified spores were ineffective in the prevention or delay of the growth of Ehrlich ascites tumor. These data indicate that C. perfringens can be a potent antitumor agent without producing the harmful anaerobic infection of solid tumors (clostridial oncolysis.

Animals↗
PubMed1977

Induction of antituberculous immunity by polysaccharidic contaminants of crude ribosomal vaccines isolated from Mycobacterium bovis, strain BCG.

Crude ribosomal fractions isolated from the BCG strain of Mycobacterium bovis are capable of inducing antituberculous immunity in CF-1 mice. These crude preparations contain varying amounts of polysaccharides in addition to ribosomal ribonucleic acid and proteins. Whereas these latter two constituents of the crude fractions were found inactive, high levels of antituberculous immunity were induced by a ribosomal sub-fraction significantly enriched with polysaccharides. These results strongly suggest that polysaccharides play an important role in the induction of antituberculous immunity in CF-1 mice immunized with crude ribosomal fractions isolated from the BCG strain and that if ribosomal proteins and/or RNA are of a certain importance, their role would be secondary (complexes providing physical support to polysaccharides, adjuvant, etc.).

Animals↗
PubMed1975

Preservation of mycobacterial suspensions at -55 degrees C.

Suspensions in dilute Sauton's medium of 14 mycobacterial strains grown under identical conditions were prepared with bacilli harvested at their midlog phase of growth,and were frozen and stored at -55 degrees C. Survivals, estimated by CFU determinations after periodic intervals of storage, showed no adverse effect of freezing and thawing on any of the strains. Effectiveness of preservation, however, varied from strain to strain and no correlation existed between effectiveness and species of mycobacteria. No noticeable changes in the virulence of the H37Rv strain and in the immunizing activity of BCG were detected after prolonged storeage. Results of experimentsperformed with two strains suspended in seven diluents suggest that some are more suitable for long-term preservation, particularly so for the more sensitive one.

Animals↗
PubMed1975

Factors affecting the immunizing activity of ribosomal fractions isolated from Mycobacterium tuberculosis var. bovis strain BCG.

Levels of antituberculous immunity similar to those induced by live BCG vaccine were detected in CF1 mice immunized with ribosomal fractions isolated from Mycobacterium tuberculosis var. bovis, strain BCG, and challenged 3 weeks later with the virulent H37Rv strain of Mycobacterium tuberculosis var. hominis. The activity of the crude ribosomal preparations was found to be a function of the immunizing doses and the immunity induced by 1.0-mg doses remained at the same high level after 4 weeks of storage at 4 degrees C but decreased markedly thereafter. Dialysis and lyophilization had no detrimental effects on the activity of the crude preparations whereas purification by column chromatography on Sephadex G-200 annihilated their biological activity. Crude low-polysaccharide-containing preparations were found inactive even at the 1.0-mg dose level and results of experiments performed with crude ribosomal fractions of varying polysaccharide contents strongly suggest that polysaccharides, or RNA-polysaccharide complexes, may play an important role in the induction of immunity with crude ribosomal fractions isolated from the BCG strain of Mycobacterium tuberculosis var. bovis.

Animals↗