Relationships between chemical constitution and germicidial effect. 28. Preparation, antimicrobial and anthelminthic effect of diiosothiocyanates]

In comparison with monoisothiocyanates, diisothiocyanates were either less active or of the same activity against bacteria and fungi. None of the compounds tested possessed antimicrobial activity worth investigating further. However, compound No. 2 (2,4-diisothiocyanatomethyl ethoxybenzol) and compound No. 5 (1,3-dimethyl-4,6-diisothiocyanatomethylbenzol) were more active as anthelmintics against Enchytraeus than the p-phenylene diisothiocyanates.     

Comparison of the specificty of human and bovine tuberculin PPD for testing cattle. 1--Republic of Ireland.

A tuberculin testing trial in cattle was carried out in the Republic of Ireland to compare the specificity for bovine tuberculosis of a human purified protein derivative (PPD) tuberculin (Weybridge) with that of a bovine PPD (Rotterdam), and to determine whether discrimination between specific and non-specific reactions to mammalian tuberculin is better with doses of tuberculins smaller than those traditonally used for testing cattle. Tests were carried out in 510 cattle, 395 of which were shown by post mortem examination to be tuberculous and 115 non-tuberculous. Three dilutions at five-fold intervals of both mammalian tuberculins were used together with two dose levels of avian tuberculin PPD (Weybridge), and all reactions were measured both by increase in skin fold thickness and by diameter of induration. In the environment of this trial, the bovine PPD was shown to be more specific for bovine tuberculosis than the human PPD, and particularly in differentiating from "skin tuberculosis". There was no indication of greater specificity at lower doses of tuberculin. Measurement of induration diameter proved a satisfactory alternative method of reading tuberculin reactions in cattle under field conditions.     

A simple method for isolating leucocytes from bovine blood and their separation into lymphocyte and granulocyte fractions.

A method for the separation of leucocytes from bovine blood and its separation into lymphocyte and granulocyte fractions is described. The method, involving flash lysis of the erythrocyte population, was found to yield large numbers of viable cells suitable for maintenance in tissue culture medium and hence of value in immunological studies.     

Vascular responses in the equine digit.

The digital circulation was isolated in 12 ponies under pentobarbital anesthesia. Blood flow was either controlled by a pump or measured under natural perfusion. The responses to rapid changes and stoppages of blood flow indicated no evidence of autoregulation or reactive hyperemia. Local administration of acetylcholine, histamine, and prostaglandins E1 and E2 decreased prevenous resistance, whereas epinephrine and serotonin caused prevenous constriction. Large doses of epinephrine and serotonin decreased venous caliber. The effects of prostaglandins A1 and F2alpha were variable. The equine digital vasculature responds to changes in flow and to vasoactive agents like the canine forelimb skin vasculature.