摘要:

Details are given of a colorimetric method for the estimation of trypsin that can be utilized for the evaluation of the proteolytic activity of pancreatic secretion. Being an adaptation of a method that has been used successfully in a clinical laboratory for many years, it is suitable for routine clinical use. Like Anson's method it depends upon the colour reaction between the tyrosine–tryptophane radicals of a protein substrate and Folin's phenol reagent, but embodies the following features: the results cannot be influenced by the presence of peptidases in the enzyme solution, since the procedure is based upon the estimation of a casein substrate before and after digestion, and not upon the digestion products; the digestion is carried out at 37 °C.; by reference to a curve the enzyme content can be expressed in terms of trypsin nitrogen. Results obtained with this method showed a reasonable degree of constancy, the average deviation from the mean being ±3.3% and the maximum deviation, ±8.4%.

ISSN:1923-4287    

DOI:10.1139/cjr47e-014

出版商:NRC Research Press    

年代:1947

数据来源: NRC

摘要:

The vitamin A activity was determined biologically and carotene content colorimetrically on 14 different commercial brands of tomato juice and on the juice prepared from eight different varieties of tomatoes. The vitamin A activity and the carotene content of the commercial brands were well within the range of the values obtained for the different varieties and a probable correlation was found between the vitamin A activity and the carotene content of the different varieties. The mean value for the vitamin A activity of the commercial brands was 11.6 I.U. per cc. (329 I.U. per ounce) showing that tomato juice may contribute significantly to the dietary vitamin A. The amount of lycopene-like compounds in tomato juice is considerably higher than the carotene compounds and was found to vary between different brands and different varieties. A substance was shown to be present in processed tomato juice that had the properties of α-tocopherol in biological assays for vitamin A activity.

ISSN:1923-4287    

DOI:10.1139/cjr47e-015

出版商:NRC Research Press    

年代:1947

数据来源: NRC

摘要:

Highly toxic filtrates of cultures ofC.botulinum, Type A, when treated with 0.5% formalin and incubated at 37 °C. for several weeks became non-toxic. These toxoids induced resistance in mice and guinea-pigs to several thousand times the amount of Type A botulinus toxin required to kill a normal animal of the same species.In general, three 1.0 ml. doses of the fluid toxoid protected over 60% of inoculated mice against 100,000 lethal doses of Type A botulinus toxin. Six weeks after receiving a 5.0 ml. dose of fluid toxoid, some 88% of guinea-pigs survived the injection of 160,000 lethal doses of Type A toxins. The antitoxic titres of their sera ranged from < 0.001 to 10 units per ml. Alum precipitation increased the effectiveness of the toxoid as an immunizing agent in mice; two 1.0 ml. doses protected about 80% of mice against 100,000 lethal doses of Type A toxin. In guinea-pigs, the immunity induced by 5.0 ml. of alum-precipitated toxoid was similar to that observed following the injection of 5.0 ml. of the fluid material. No correlation was apparent between the flocculative titre of the culture filtrates before and after formalinization and their antigenicity.

ISSN:1923-4287    

DOI:10.1139/cjr47e-016

出版商:NRC Research Press    

年代:1947

数据来源: NRC

摘要:

Fluid and alum-precipitatedC.botulinumType B toxoids were prepared by methods very similar to those used in the production of Type A toxoid, as described in a preceding paper. These Type B toxoids had little protective effect in mice but induced a moderately high degree of immunity in guinea-pigs as shown by their resistance to multiple lethal doses of Type B toxin and the development of Type B antitoxin. A relationship was observed between the Type B antitoxic titre and resistance to Type B toxin.

ISSN:1923-4287    

DOI:10.1139/cjr47e-017

出版商:NRC Research Press    

年代:1947

数据来源: NRC

摘要:

When Types A and BClostridium botulinumtoxoids were mixed the resultant divalent toxoid was found to have a very high protective potency against both Type A and Type B botulinus toxin. The resistance to Type A toxin induced in guinea-pigs and mice by the divalent toxoid mixture was only slightly less than that conferred by a similar volume of univalent Type A toxoid. Guinea-pigs given the divalent toxoid developed a comparable or slightly higher degree of immunity to Type B toxin than those injected with univalent Type B toxoid.Although no evidence of reciprocal protection had been observed between Type A and Type B toxoids, admixture with Type A toxoid appreciably increased the antigenicity of the Type B toxoid for mice. Mice immunized with the divalent, A + B, toxoid exhibited a higher level of resistance to Type B toxin than those given the same number of doses of Type B toxoid alone. No adjuvant effect was noted on mixing Type A or Type B botulinus toxoids with tetanus or diphtheria toxoids.

ISSN:1923-4287    

DOI:10.1139/cjr47e-018

出版商:NRC Research Press    

年代:1947

数据来源: NRC