Biomedical subjects
Publications and source records attributed to J Konowalchuk.
Seven cell lines were compared with Y-1 and Vero cells for morphological response to E. coli toxic products. FL and WI-38, like Y-1 and Vero, responded to heat-labile enterotoxin. FL, HEp-2, HeLa, and BGM, like Vero but not Y-1, responded to heat-labile cytotoxin. FL was comparable to Vero in sensitivity to these two toxic products.
Nineteen commercial juices or beverages were tested for inactivation of poliovirus type 1. Grape and apple juices and tea were particularly antiviral. Although antiviral in aqueous solution, ascorbic acid was ineffective after addition to juices.
A variety of apple beverages were tested for antiviral activity against poliovirus 1 or coxsackievirus B5. Freshly prepared apple juice was particularly antiviral, but its activity declined more readily than that of commercial juice in response to heat and storage. The component responsible for activity was located both in the pulp and skin; after ultrafiltration, activity was present in fractions greater and less than molecular weight 10,000. Virus infectivity was not restored from virus-apple juice complexes with gelatin, serum, Tween 80, or polyethylene glycol.
Isoelectric focusing of a heat-labile cytotoxin of Escherichia coli H30 revealed the presence of two molecular variants, pI 7.2 and a comparatively small quantity of pI 6.8. Predominant component pI 7.2 had a molecular weight of 28,000, induced some fluid accumulation in rabbit ileal loops, and showed no morphological response in Y-1 cells but a strong cytotoxic effect on Vero cells.
The morphological response of Vero cells to Escherichia coli heat-labile enterotoxin was similar to that of cholera toxin and was accompanied by increases in the intracellular level of cyclic AMP. The effects of both enterotoxins were enhanced by the presence of phosphodiesterase inhibitor and inhibited by heat or specific antisera. Accumulation of cyclic AMP preceded the morphological response.
Five heat-labile, partially purified toxic products of Escherichia coli were distinguished by isoelectric focusing, molecular weight, and neutralization with homologous and heterologous antisera. Only two affected the morphology of Y-1 cells, induced fluid accumulation in rabbit ileal loops, and stimulated production of cyclic AMP in Vero cells; these two did not cross-neutralize and only one showed cross-neutralization with cholera antitoxin. The remaining three products were cytotoxic for Vero cells.
The continuous cell line of African green monkey kidney, Vero, showed characteristic morphological changes in response to culture filtrates from toxigenic strains of Escherichia coli. The response compared favorably with that of Y-1 (mouse adrenal) and CHO (Chinese hamster ovary) cells. Vero cells were the simplest and most economical to maintain in the laboratory.
A cytotoxin was found in culture filtrates of a number of Escherichia coli strains that differed from the known heat-stable and heat-labile enterotoxins of E. coli. It was cytotoxic for Vero but not for Y-1 or CHO cells, and its effect on Vero was distinctly different from that of heat-labile enterotoxin. It was labile to heat and antigenically different from heat-labile enterotoxin, and membrane filtration indicated a molecular weight of 10,000 to 30,000.
Solid-phase radioassay was applied to the determination of protein A after release from staphylococcal cells with lysostaphin. Assays can be completed in 60-90 min.
Grapes inoculated with poliovirus 1 and coxsackievirus B5 were washed with water, 0.5% polyehtylene glycol, or phosphate-buffered saline with 1% serum. These washes were equally efficient at removing virus but much of the virus in the water was noninfectious until treated with 0.5% polyethylene glycol.
Infusions and extracts of different grapes inactivated poliovirus; agents responsible for this property resided in the skin of the grape. Commercial grape juice at both natural and neutral pH inactivate various enteric viruses and herpes simplex virus; a 1,000-fold reduction in poliovirus infectivity occurred after incubation with grape juice, pH 7.0, for 24 h at 4 degrees C. A variety of wines were antiviral but to a lesser extent than grape juice; red wines were more antiviral than white. Antiviral activity was demonstrable in fractions of grape juice varying in molecular weight from less than 1,000 to greater than 30,000 as determined by membrane filtration. Some restoration of poliovirus infectivity from virus-grape juice complexes was achieved with 1% gelatin, 0.1% Tween 80, 0.5% polyvinyl pyrrolidone, and 0.5% polyethylene glycol.