Specificity and sensitivity of skin test reactions to extracts of Toxocara canis and Ascaris suum. I. Skin tests done on infected guinea pigs.

The specificity and sensitivity of adult and larval somatic antigens, and perienteric fluid of Toxocara canis and Ascaris suum were investigated by using intradermal skin tests in guinea pigs. These animals were infected with low doses (0.01, 0.1 or 1.0 egg/g) of these helminths. Toxocara larval antigen (TL) induced larger reactions in Toxocara-infected animals than did the other antigens, suggesting a superior sensitivity for this antigen. In addition, Ascaris perienteric fluid (AP) provoked skin responses in these animals of a magnitude similar to those induced by TL. The reciprocal relationship, i.e., comparable reactivity of AP and TL in Ascaris-infected animals, was not apparent. In general, Ascaris larval antigen and AP elicited larger intradermal reactions than other antigens in Ascaris-infected animals. The results of this study indicated no superiority of adult antigens in differentiating Ascaris and Toxocara infections.     

Trypsin and alpha-amylase activities in the pancreas of guinea pigs. II. Effect of per os and intra-intestinal infection with invasive ova of Ascaris suum

The guinea pigs were infected orally or intraintestinally (after laparotomy) with 5000 invasive eggs of Ascaris suum. On the 7th day after infection the invasion was controlled by lung's weight, degree of congestion, and number of larvae in the lungs. The activity of amylase was determined according to Fennel method, trypsin to Anson method. The activities of both enzymes in pancreas of orally infected animals (after laparotomy or not) were lower, and relative weight of lungs of these animals was higher than in control animals. In pancreas of guinea pig with invasive material introduced into its, the activities of amylase and trypsin were higher than in control animals, but only the activity of trypsin differed significantly.     

Trypsin and alpha-amylase activities in the pancreas of guinea pigs. III. Effect of homogenates of invasive ova of Ascaris suum and organic acids C2-C6 on the activity of enzymes in pancreatic extracts

The studies were carried out on pancreas extracts from guinea pigs free of parasite invasion. The activity of trypsin was determined according to the method of Anson, and amylase of Fennel method. The measurements of activity were done at the presence of homogenized invasive eggs of Ascaris suum, and the mixture of volatile organic acids C2-C6 (at concentrations of 30.3 and 0.3 mM/l). In samples with homogenized invasive eggs of A. suum the amylase activity remained unchanged while the activity of trypsin was considerably higher (p less than 0.01). The introduction of the organic acids at conc. 30 mM/l into the samples was the reason of lower amylase activity. No influence of these acids on trypsin activity in pancreas extracts was observed.