摘要:

Shock was produced in the albino rat by means of a standardized method of blood removal. Coenzyme A (CoA) was extracted from the liver and estimated during the reversible and the irreversible phases of shock. The assay procedure was designed so that each animal served as its own "control".The CoA concentration in the liver fell rapidly during the first half hour of shock and thereafter at a progressively slower rate as the state of shock became more severe. Escape of the coenzyme from the mitochondria and the nucleus into the cytoplasm of the liver cells became evident during the reversible phase, and its breakdown in the cytoplasm began with the onset of the irreversible phase. Even at death, however, the CoA concentration of the liver was rarely lower than 35% of the original concentration. It is unlikely, therefore, that the decrease in the CoA content of the liver is a key factor in the initiation of the state of irreversibility in hemorrhagic shock.

ISSN:0008-4018    

DOI:10.1139/o64-001

出版商:NRC Research Press    

年代:1964

数据来源: NRC

摘要:

The acute hypoxia, caused by severe blood loss, gives rise to the rapid breakdown of glycogen in the liver and concurrent increase in the concentration of ATP in the mitochondria. The increase in adenosine triphosphate (ATP) continues until the onset of the reversible phase of shock. The glycogen reserve approaches depletion during the late reversible phase. Simultaneously, the generation of ATP in the mitochondria ceases and the concentration begins to fall. It would appear that at this time the adenylate kinase mechanism in the mitochondrial membrane comes into play to convert the adenosine diphosphate (ADP) into ATP and adenosine monophosphate (AMP). As the condition becomes irreversible the residual ATP and phosphorylated intermediates of the Embden–Meyerhof system undergo rapid hydrolysis with liberation of AMP and inorganic phosphate in the cytoplasm.The concentration of the pyridine nucleotides undergoes no change in any of the liver cell components until the onset of the irreversible phase of failure. Thereafter, these nucleotides undergo a progressive conversion to the reduced form.

ISSN:0008-4018    

DOI:10.1139/o64-002

出版商:NRC Research Press    

年代:1964

数据来源: NRC

摘要:

The teratogenicity of α-N-phthalimidoglutarimide (thalidomide) and related substances was studied in the developing chick embryo. Whereas doses of thalidomide up to 10 mg had little or no effect on the 4-day-old embryo, 0.5 mg injected into the yolk sac just prior to incubation produced micromelia and edema, which were rarely seen in the controls. Other abnormalities observed were rumplessness, cerebral hernia, and defects of the eyes and beak, which were also present, but to a lesser extent, in the controls.Metabolites of thalidomide which are found in the urine of rabbits after oral administration of this drug were also investigated. α-N-Phthaloylglutamine and α-N-phthaloylglutamic acid had little effect, suggesting that hydrolytic cleavage of the glutarimide ring of thalidomide results in decreased teratogenicity. However, increased teratogenicity was shown by hydroxylated derivatives of these compounds and of thalidomide in which the hydroxyl group was located in the 3- or 4-position of the phthalimido group, the 4-hydroxylated derivatives being the more effective.It was found that 4.0 mg ofL-glutamine, injected simultaneously with 2.0 mg of α-N-(4-hydroxyphthaloyl)-glutamine, gave complete protection against micromelia and edema and reduced the incidence of other abnormalities almost to the control level. No protection was given byL-glutamic acid, pyridoxal hydrochloride, pteroyl-L-glutamic acid, citrovorum factor, nicotinamide, or quinolinic acid. These results suggest that α-N-(4-hydroxyphthaloyl)-glutamine and probably its congeners may interfere with the metabolism of glutamine.

ISSN:0008-4018    

DOI:10.1139/o64-003

出版商:NRC Research Press    

年代:1964

数据来源: NRC

摘要:

A study of blood concentration of α-ketoglutaric, pyruvic, and total "branch chain" keto acids in infectious hepatitis, hepatic cirrhosis, and obstructive jaundice is reported. The concentration of α-ketoglutarate was often abnormal, but the total "branch chain" keto acid concentration was only raised in two cases, and that of pyruvic acid in one case out of 15. The significance of the results is discussed.

ISSN:0008-4018    

DOI:10.1139/o64-004

出版商:NRC Research Press    

年代:1964

数据来源: NRC

摘要:

C14-labeled adenine, guanine and cytosine, and tritiated thymidine were incorporated into the deoxyribonucleic acid of salmon milts, either by injection into the milts of live fish or into excised milts. The amount incorporated was very small. Under the experimental conditions radioactive nucleosides, deoxyuridine, adenosine 5′-mono- and tri-phosphates, orotic acid, uracil, ribose 1-phosphate, and ribose 5-phosphate were not incorporated. It is suggested that these results may be due to the comparative impermeability of the cells to the various compounds.

ISSN:0008-4018    

DOI:10.1139/o64-005

出版商:NRC Research Press    

年代:1964

数据来源: NRC

摘要:

The extracellular protein layer which surrounds the lumen of the gizzard of the chicken has been reinvestigated to determine if it is a keratin. The lining is insoluble in keratin solvents such as urea-bisulphite or Swan's reagent as well as thioglycollate and performic acid. In addition, it contains only 1.45% sulphur so that disulphide bonds cannot play a major role in its consolidation. The lining is insoluble in acids but readily dispersed in alkali without breaking of covalent bonds. The dispersion in alkali is retarded by electrolytes. The lining is hydrolyzed by trypsin and chymotrypsin at pH 8.0 but is resistant to pepsin at pH 2.0. An alkaline dispersion of the lining is heterogeneous in the ultracentrifuge, but not grossly so, with a mean sedimentation coefficient of 5.6 svedbergs. Electron microscope studies of the lining suggest it is an amorphous, precipitated protein, which is consistent with the observation of three hazy rings in X-ray diffraction powder patterns reflecting spacings of 3.5, 4.6, and 9.4 Å. Amino acid analysis shows a ratio of more than three acidic groups to one basic, with no carbohydrate residues and little lipid in the protein layer. These observations are interpreted as indicating the precipitation of an amorphous, non-keratin, acidic, abrasion-resistant protein from the glandular mucosa by the acid in the gizzard.

ISSN:0008-4018    

DOI:10.1139/o64-006

出版商:NRC Research Press    

年代:1964

数据来源: NRC

摘要:

Liver slices from rats fed a commercial diet incorporated more acetate-1-C14into cholesterol than did slices from rats fed semisynthetic diets. The stimulatory effect of the commercial diet was due in part to a saponifiable component of the ether-soluble portion of the diet, possibly linoleic acid; and in part to the ether-insoluble portion of the diet. Dietary fats stimulated acetate incorporation into cholesterol more when mixed with the ether-insoluble portion of commercial diet than when mixed with semisynthetic diet. With either diet, unsaturated fats stimulated incorporation more than saturated fats. The rate-limiting step in these experiments was prior to mevalonic acid in the cholesterol biosynthetic pathway. Acetate incorporation into fatty acids was little affected by the nature of the dietary fat or the diet in which it was fed.

ISSN:0008-4018    

DOI:10.1139/o64-007

出版商:NRC Research Press    

年代:1964

数据来源: NRC

摘要:

Liver homogenates from fetal rats gave good incorporation of labelled acetate into cholesterol and fatty acids, but liver slices or homogenates from suckling rats gave very little incorporation. The amount of acetate incorporated increased greatly as soon as the suckling rats began to eat a commercial diet. Mevalonic acid was incorporated into cholesterol equally well by liver slices from suckling and weaned rats. Acetate given orally or intraperitoneally to intact rats was incorporated into liver cholesterol and fatty acids to a lesser extent in suckling rats than in rats weaned to a commercial diet. Plasma cholesterols were elevated in suckling rats and dropped to normal adult levels at weaning. Liver cholesterols tended to be slightly higher in suckling rats.

ISSN:0008-4018    

DOI:10.1139/o64-008

出版商:NRC Research Press    

年代:1964

数据来源: NRC

摘要:

Methods are described which are suitable for the quantitative analysis of the alkali-stable oligonucleotides which result from the hydrolysis of ribonucleates in molar alkali at room temperature for 90 hours. The alkali-stability of the oligonucleotides is presumed to result from 2′-O-methyl substitution of ribose residues and this assumption is supported by the relatively slight reactivity of the purine 2′-O-methyl ribosides in the orcinol color reaction for pentoses. The existence of all of the 16 possible dinucleotides as part of ribonucleate chains has been established. The quantity of alkali-stable trinucleotides is much greater than would be expected for a random spatial distribution of 2′-O-methyl ribosides in ribonucleate chains.

ISSN:0008-4018    

DOI:10.1139/o64-009

出版商:NRC Research Press    

年代:1964

数据来源: NRC

摘要:

A modified Yemm and Cocking ninhydrin–cyanide reagent has been developed which gives quantitative color yields with free amino acids, but much lower yields with most peptides tested. Using this reagent, a more sensitive assay for peptidase activity has been developed, and its use in column fractionation of peptidase activity is described.The ε values for peptides, obtained with the modified reagent, are compared to those obtained with the conventional ninhydrin–hydrindantin reagent. The formation of Ruhmann's Purple by the modified reagent is inhibited by Tris buffer. No inhibition occurs with the ninhydrin–hydrandantin reagent. The absorption spectra of the two reaction mixtures indicate that Tris reacts in a different manner with the two reagents.

ISSN:0008-4018    

DOI:10.1139/o64-010

出版商:NRC Research Press    

年代:1964

数据来源: NRC