摘要:

A study has been made of the effect of various concentrations of several liver extract preparations on the migration of cells, chiefly leucocytes, from explants of guinea pig bone marrow. The migration has been shown to be stimulated by an extract of liver, which shows incomplete activity in the treatment of pernicious anemia. Two clinically active fractions have been shown to be inactive in the stimulation of cell migration. The migration of cells from explants cannot be used under the conditions described as a test for antipernicious anemia activity of liver extract preparations.

ISSN:1923-4287    

DOI:10.1139/cjr49e-033

出版商:NRC Research Press    

年代:1949

数据来源: NRC

摘要:

This report contains an account of a systematic study on the morphology of five rickettsiae pathogenic to man, investigated with the electron microscope. The work has bearings on the biology, antigenic structure, and taxonomy of the rickettsiae.

ISSN:1923-4287    

DOI:10.1139/cjr49e-034

出版商:NRC Research Press    

年代:1949

数据来源: NRC

摘要:

A method is presented by which hyaluronidase may be detected by observing its action on the colony characteristics of mucoid strains ofStreptococcus pyogenesand certain strains ofStreptococcusof Lancefield Group C growing on agar. This effect is due to destruction of the capsules of these organisms and is caused by hyaluronidase from all sources tried. Bacteria are tested for hyaluronidase production by streaking on seeded plates; fluids are tested by using assay cylinders or filter paper disks.The method is convenient and has the advantage of detecting small concentrations of the enzyme, to a limit of between 0.001 and 0.0001 turbidity reduction units per ml. The test may be elaborated to give a means of biological assay that may be used where there are substances in the medium or diluting fluid that interfere with assays by other methods.Provided the colonies do not autolyze during the 12 to 18 hr. required for the test, all mucoidS.pyogenesstrains are suitable. However, among the Group C strains one was found with a capsule not destroyed by hyaluronidase, indicating a separate capsular type.In testing certain genera for hyaluronidase production, notablyStreptococcusandMicrococcus, antibiotic activity may interfere with the test. These inhibitory strains are relatively infrequent.

ISSN:1923-4287    

DOI:10.1139/cjr49e-035

出版商:NRC Research Press    

年代:1949

数据来源: NRC

摘要:

A quantitative investigation of the common colorimetric procedures used for determining inorganic, phosphate was made to determine the factors affecting the sensitivity and color stability. A method is presented that is accurate to within ± 2% and is sufficiently sensitive to give quantitative color development with less than 1 γ of phosphorus. The color produced is quite stable for colorimetry. The method has been adapted to the determination of phosphorus in 0.1 or 0.02 ml. of plasma, serum, or urine or in the protein-free filtrate residue from the determination of sodium, potassium, calcium, and chloride in 0.4 ml. of plasma.

ISSN:1923-4287    

DOI:10.1139/cjr49e-036

出版商:NRC Research Press    

年代:1949

数据来源: NRC

摘要:

The usual method of determining diphosphothiamine (DPT) by its cocarboxylase activity proved unreliable when applied to blood extract because of a marked upward drift of the results during the period of measurement. This phenomenon, which was associated with excessively high recovery values, was tentatively attributed to a synthesis of DPT since the presence of 1 × 10−3molar iodoacetate abolished the increase in carboxylase activity. Judging from recovery experiments, the addition of iodoacetate to the reactants permitted a more reliable estimation of the DPT content of blood extract.

ISSN:1923-4287    

DOI:10.1139/cjr49e-037

出版商:NRC Research Press    

年代:1949

数据来源: NRC

摘要:

A purified diet, deficient in choline and containing 18% casein, results in fatty infiltration of the liver in ducklings killed at four weeks. Total liver lipids is about 13%, the normal value being 6 to 7%. Addition of 0.1 or 0.3% choline chloride results in nearly normal livers. In this respect, ducklings differ from chicks and are comparable to rats and dogs. Betaine has a slight lipotropic activity but does not stimulate growth and has no antiperotic properties. DL-methionine, when added to a purified diet containing 9% casein or to a simplified diet containing 15% casein, has no lipotropic activity. On the contrary, this ammo acid increases the total lipids and the severity of fatty infiltration of the livers. Choline has a triple function in ducklings; it promotes growth, prevents hepatic fatty infiltration, and perosis.

ISSN:1923-4287    

DOI:10.1139/cjr49e-038

出版商:NRC Research Press    

年代:1949

数据来源: NRC

摘要:

Rabbit polymorphonuclear leucocytes contain an active phosphatase that readily hydrolyzes disodium phenyl phosphate. The pH activity curve of the enzyme was found to have two maxima, one in the region of pH 10 and the other in the region of pH 5. The alkaline phosphatase was much more active than the acid phosphatase. The concentration of alkaline phosphatase in rabbit white cells was approximately one thousand times that of the enzyme in the serum. Under the conditions of study, the alkaline phosphatase activity was proportional to the concentration of the enzyme. The effect of substrate concentration on the enzyme activity was studied and the Michaelis constant (Ks) determined. An excess of substrate inhibited the enzyme. The course of the reaction was linear with time for the first 60 min.; after 90 min. the activity fell off faster than would be expected if the reaction were of the first order.Magnesium and glycine, in low concentrations, caused an increase in the enzyme activity, whereas zinc, cyanide, borate, phosphate, bile salts, and glycine, in higher concentrations, were inhibitory. Fluoride had no demonstrable effect. Surface-active substances, such as saponin, bile salts, or alkyl sulphate, liberated the enzyme from the cells. Similar results were obtained when α-glycerophosphate or β-glycerophosphate was used as the substrate.The alkaline phosphatase can be considered to belong to Class AI of Folley and Kay (22) and the acid phosphatase to Class AII. The alkaline phosphatase can also be considered to be a Phosphatase II of Cloetens (9).

ISSN:1923-4287    

DOI:10.1139/cjr49e-039

出版商:NRC Research Press    

年代:1949

数据来源: NRC