摘要:

Each of 14 commercial insulin preparations was assayed for insulin activity using three biological assay methods. In Assay I, 32 rabbits were employed using the "twin cross-over" design. Per cent reductions of blood sugar calculated from blood-sugar levels determined before and one and one-half, three, and five hours after the subcutaneous injection of insulin were used in estimating potency. In Assay II, 16 rabbits were used in a 4 × 4 Latin square design. Blood-sugar levels determined 50 min. after the intravenous injection of insulin were used in estimating potency. In Assay III, 288 mice were employed in a two-level quantal response design. The proportions of animals convulsing in groups of 36 mice after the subcutaneous injection of insulin were used in measuring potency. The agreement between results obtained by the three methods was found to be satisfactory. The average standard error for the estimate of potency was 13% for Assay I; 10% for Assay II; and 9% for Assay III.

ISSN:1923-4287    

DOI:10.1139/cjr50e-005

出版商:NRC Research Press    

年代:1950

数据来源: NRC

摘要:

In this paper a comparison is made between the growth and toxin production ofCorynebacterium diphtheriaein aerated and classical still cultures. It is shown that in well aerated cultures fermentation proceeds more rapidly and toxin appears earlier than in still cultures. However, to obtain maximum results in aerated cultures it is necessary to increase the amount of fermentable substance over that present in the media of still cultures. When cultures are aerated with two to three volumes of air per minute and an extra amount of fermentable carbohydrates is added to the growing cultures at a suitable interval a higher yield of toxin is obtained than in still cultures in similar media. The maximum concentration of toxin, moreover, is reached in the aerated cultures after about 60 hr. of incubation as compared with about 120 hr. in still cultures.

ISSN:1923-4287    

DOI:10.1139/cjr50e-006

出版商:NRC Research Press    

年代:1950

数据来源: NRC

摘要:

The present communication deals with a survey of neutralizing antibodies to mouse-adapted Lansing strain of poliomyelitis virus in the sera of acute, convalescent, and normal individuals during a 1946 epidemic. Two-phase sera were obtained from residents of Ontario and British Columbia and convalescent and normal sera from Quebec. In the sera of 17 out of 35 Ontario patients neutralizing antibodies were demonstrable during the acute stage. In four of these seropositive individuals, there was an increase in the neutralizing titer during convalescence and in three patients there was a notable drop in the titer. The remaining 18 patients were found to be seronegative during both the acute and convalescent stages. Sera from six out of nine British Columbia patients, likewise contained neutralizing antibodies to the Lansing strain of virus during the acute stage. In four of these the titer remained unchanged during convalescence, in one the titer decreased, and another patient became seronegative. Of the remaining three, two continued to be seronegative and one became seropositive during convalescence. Positive neutralization reactions were obtained with 17 out of 44 convalescent sera from Ontario and 62 out of 146 convalescent sera from Quebec Sera from 51 children without history of poliomyelitis and 100 adult sera taken at random from specimens submitted for Wassermann tests were obtained from Quebec. Of the children's sera 43%, and of the adults’, 48%, contained neutralizing antibodies. The results obtained closely agree with those reported by American workers.

ISSN:1923-4287    

DOI:10.1139/cjr50e-007

出版商:NRC Research Press    

年代:1950

数据来源: NRC

摘要:

In synthetic diets fed to weanling rats, methionine and fat must be present in a definite ratio in order to maintain a serum alkaline phosphatase activity equal to that obtained on a standard laboratory diet of animal checkers. This ratio is approximately 1:25 by weight for a diet containing 8.5% fat. Increased fat enhances, while increased methionine lowers, the serum phosphatase activity. Although in some experiments methionine was fed in concentrations sufficient to lower phosphatase activity to what has been considered definitely subnormal values, growth was good and the general condition of the animals was excellent. However, beyond certain concentrations of the amino acid, food consumption decreased and weight losses occurred. Cystine had no effect in opposing the action of methionine on serum alkaline phosphatase.

ISSN:1923-4287    

DOI:10.1139/cjr50e-008

出版商:NRC Research Press    

年代:1950

数据来源: NRC

摘要:

The urinary excretion of corticosteroids and ketosteroids was measured in infants during the first week of life and at four and 18 months of age. It was found that corticosteroid excretion increased with age while the excretion of ketosteroids declined from birth, but was again at a similar level to that of one-to three-day-old infants in the 18-months-old child. The excretion of androgenic substances did not parallel the excretion of ketosteroids, these substances being present in minute amounts at birth and rising gradually with increasing age. It is suggested that the involution of the fetal adrenal cortex is associated with a declining production of nonandrogenic ketosteroids.

ISSN:1923-4287    

DOI:10.1139/cjr50e-009

出版商:NRC Research Press    

年代:1950

数据来源: NRC

摘要:

Since it has been established (a) that the alkaline phosphatase activity of the plasma is increased in obstructive jaundice, (b) that the white cells are rich in alkaline phosphatase, (c) that this alkaline phosphatase is liberated from the cells in the presence of bile salts, and (d) that bile salts accumulate in the blood when the biliary tract is obstructed, there remained the possibility that the increase in plasma alkaline phosphatase observed after obstruction to the biliary tract might be the result of the liberation of alkaline phosphatase from the white cells by the retained bile salt. However the injection of bile salt into the blood stream of rabbits caused an increase in the acid phosphatase activity of the plasma with no significant change in the concentration of alkaline phosphatase. Since there is no increase in the acid phosphatase of the plasma in obstructive jaundice, these experiments provide no evidence for the theory that the increase in plasma alkaline phosphatase that follows biliary obstruction is the result of the retention of bile salt.

ISSN:1923-4287    

DOI:10.1139/cjr50e-010

出版商:NRC Research Press    

年代:1950

数据来源: NRC

摘要:

Many normal cerebrospinal fluids contain an alkaline (pH 9.8) and an acid (pH 4.9) phosphatase. Both the alkaline and the acid phosphatase were significantly increased in the spinal fluids from patients with meningitis or poliomyelitis, but not in the fluids from patients with syphilis. The alkaline phosphatase activity was correlated with both the concentration of protein in the spinal fluid and with the white cell count, whereas the acid phosphatase was correlated with neither. When correction was made for the significant correlation between cell count and protein concentration, the partial correlation between alkaline phosphatase activity and both protein concentration and cell count remained significant statistically. In pathological conditions it appears likely that the alkaline phosphatase is derived partly from the polymorphonuclear leucocytes in the fluid and partly from the blood plasma. The acid phosphatase is probably derived from the lymphocytes of the fluid and possibly also from the blood plasma. It is unlikely that either of these enzymes comes from the substance of the brain or spinal cord. Acid phosphatase would be of more value than alkaline phosphatase as a diagnostic aid, since normal fluids contain much less of this enzyme.

ISSN:1923-4287    

DOI:10.1139/cjr50e-011

出版商:NRC Research Press    

年代:1950

数据来源: NRC