Purification of Tissue Forms (Amastigotes) of Trypanosoma cruzi by Immunoaffinity Chromatography1

A rapid and simple method for the purification of amastigotes of Trypanosoma cruzi from spleens of infected mice is described. A protein A-Scpharose 4B immunoadsorbent column bound with antisera to epimastigotes of T. cruzi was used to purify the tissue forms of this parasite. Host cells and debris are not retained, and parasites can be eluted in high yields and purity. Studies of surface glycoproteins and glycolipids of the purified amastigotes with 18 lectins of various specificities revealed the presence on the parasites of receptors for N-acetylglucosamine, N-acetylgalactosamine, D-galactose, and D-mannose binding lectins.     

Grey seals, Halichoerus grypus, of the Dee Estuary and observations on a characteristic skin lesion in British seals

Grey seals on the West Hoyle Bank feed on a variety of fish and have a high incidence of dermal lesions, often associated with emaciation and nematode parasite infection. Corynebacterium phocae has been isolated from an active lesion. The significance of large numbers of seals in the Dee Estuary bearing lesions is discussed and the occurrence of seals with lesions elsewhere in British waters is reviewed. No evidence was found to associate the dermal lesions with any environmental factor and it is probable that lesions develop as a result of infection of minor wounds.     

Medical Students in Canadian Universities: Report of Statistics, 1966-67

Enrolment in the 13 Canadian medical schools in 1966-67 reached a new high of 4230, an increase of 5.1% over 1965-66. The percentage of women among medical students (12.1%) was close to that of the preceding three years. There has been a levelling off in the decline of students from outside Canada in 1966-67, when 9.5% of medical students were non-Canadian. The decline had been primarily in the number of American students, which continues. The number of students from Commonwealth countries has shown a steady increase during the eight-year period under review; in 1966-67, they make up nearly one-half of all non-Canadian students. It was noted that 18.5% of overseas students came to Canada under governmental or intergovernmental sponsorship. Of the Canadian students, 94% came from the “home” provinces of the medical schools.     

Regulation of insulin-like growth factor 1 binding protein 3 levels by epidermal growth factor and retinoic acid in cervical epithelial cells

Insulin-like growth factors (IGFs) are important regulators of epithelial cell growth. The mitogenic activity of these factors is influenced by the levels of extracellular IGF binding proteins, including insulin-like growth factor binding protein 3 (IGFBP-3). In the present report we study the effects of epidermal growth factor (EGF) and all-trans-retinoic acid (RA) on IGFBP-3 RNA and protein levels in human papillomavirus-immortalized cervical epithelial cells. Treatment of ECE16-1 cells with 3–20 ng/ml EGF causes a marked reduction in IGFBP-3 levels. In contrast, 1 μM RA increases IGFBP-3 mRNA and protein levels in the presence or absence of 20 ng/ml EGF. The response is concentration dependent with a half-maximal increase observed at 1 nM RA. RA is able to reverse the EGF suppression when added simultaneously or 3 days after initiation of EGF treatment. Conversely, when cells are treated with RA, IGFBP-3 levels increase within 24 h and subsequent addition of EGF is without effect. Thus, the RA-dependent increase in IGFBP-3 levels is dominant over the EGF suppression. The increased IGFBP-3 levels are correlated with RA suppression of proliferation. Similar RA effects on IGFBP-3 mRNA levels were observed in other cervical epithelial cell lines (i.e., ECE16-D1, ECE16-D2, and CaSki). These results suggest that RA may act to inhibit cervical cell growth by increasing IGFBP-3 levels and reducing the extracellular concentration of free insulin-like growth factor I (IGFI) and/or, alternatively, IGFBP-3 may inhibit cell growth by direct effects on the cell, independent of IGFI. © 1994 Wiley-Liss, Inc.     

Evaluation of Probiotic Properties of Novel Brazilian Lactiplantibacillus plantarum Strains

Probiotics and Antimicrobial Proteins - Beneficial effects of Lactiplantibacillus plantarum strains have been widely reported. Knowing that the effects of probiotic bacteria are strain-dependent,...     

Inhibition of ATP-regulated K+-channels by a photoactivatable ATP-analogue in mouse pancreatic β-cells

The effects of a photoactivatable (DMNPE-caged) ATP-analogue on ATP-regulated K⁺-channels (K_ATP-channel) in mouse pancreatic β-cells were investigated using the inside-out patch configuration of the patch-clamp technique. The caged precursor caused a concentration-dependent reduction of channel activity with a K_i of 17 μM; similar to the 11 μM obtained for standard Mg-ATP. The small difference in the blocking capacity between the precursor and ATP is probably the reason why no change in channel activity was observed upon photolysis of the caged molecule and liberation of ATP. It is suggested that the part of the ATP molecule involved in the blocking reaction of the K_ATP-channel is not sufficiently protected in DMNPE-caged ATP making this compound unsuitable for studying the rapid kinetics of ATP-induced K_ATP-channel inhibition.