摘要:

SUMMARYThe concentrations of Na+and K+in the different parts of the incubated duck's egg were determined by flame spectrophotometry. From the weights of the various parts the total amounts of these ions and their distribution in the egg were calculated. It is argued that the subgerminal fluid is formed by active resorption of water and dissolved substances from the eggwhite by the living blastoderm and not by digestion of the yolk. Differences between fertilized and unfertilized eggs are given. During incubation the concentration of Na+in blood, amniotic and allantoic fluids decreases while that of K+ increases.There are quite large variations in Na+and K+concentrations in the blood, plasma and erythrocytes of ducklings, even in successive determinations in the same animal. The blood of ducklings during the first nine months of life has a higher Na+and a lower K+level than the blood during the later stages of the embryonic life.Data for the daily growth of the embryo and for the amounts of amniotic and allantoic fluids are given.

ISSN:0004-945X    

DOI:10.1038/icb.1962.20

出版商:Nature Publishing Group    

年代:1962

数据来源: WILEY

摘要:

SUMMARY3‐ and 4‐pyridine aldehydes were metabolised byMycobacterium tuberculosisBCG with the production of the corresponding acids and alcohols. The breakdown of isoniazid and the pyridine aldehydes was also observed in cell‐free extracts and some purification of the enzymes involved was achieved. It is suggested that there are two enzyme systems which metabolise isoniazid of which one may involve the intermediate formation of 4‐pyridine aldehyde.

ISSN:0004-945X    

DOI:10.1038/icb.1962.21

出版商:Nature Publishing Group    

年代:1962

数据来源: WILEY

摘要:

SUMMARYFurther investigation of pigments produced byMycobacterium tuberculosisBCG exposed to isoniazid established that the compounds were not derived from isoniazid itself. One compound was identified as riboflavine but quantitative comparison of isoniazid sensitive and resistant organisms led to the conclusion that the release of riboflavine was not relevant to the mode of action of isoniazid.

ISSN:0004-945X    

DOI:10.1038/icb.1962.22

出版商:Nature Publishing Group    

年代:1962

数据来源: WILEY

摘要:

SUMMARYCopper stimulates the uptake ofisonicotinic acid hydrazide (isoniazid) and nicotinic acid hydrazide byMycobacterium tuberculosisBCG. The inhibition of isonicotinic acid hydrazide uptake by nicotinic and benzoic acid hydrazides is reversed by copper. Other metals are ineffective. Copper also enhances the effects of hydrazides in bacteriostatic tests.

ISSN:0004-945X    

DOI:10.1038/icb.1962.23

出版商:Nature Publishing Group    

年代:1962

数据来源: WILEY

摘要:

SUMMARYA comparison has been made of the phagocytic and bactericidal abilities of macrophages washed out from guinea pig lung and mouse peritoneum. Cells from both sources were shown to be phagocytic but lung macrophages possessed relatively little bactericidal power. A new quantitative technique for measuring these aspects of cell function is described. Studies designed to assess respiration rate and acid phosphatase levels showed both to be highest in lung macrophages. The possible significance of these findings is discussed.

ISSN:0004-945X    

DOI:10.1038/icb.1962.24

出版商:Nature Publishing Group    

年代:1962

数据来源: WILEY

摘要:

SUMMARYAlkaline phosphatase (AP) levels were low (2 K.A. units/gm.) in normal AKR thymuses and the enzyme activity was not localised in the lymphoid cells. AP levels were slightly elevated in preleukaemic AKR thymuses. In AKR thymic lymphomata, AP levels were usually elevated, but the levels in individual mice were highly variable (0·3–88·5 K.A, units/gm.). When present, AP activity was localised in the lymphoma cells. Liver AP levels became elevated in leukaemic mice only after infiltration of the liver by lymphoma cells.

ISSN:0004-945X    

DOI:10.1038/icb.1962.25

出版商:Nature Publishing Group    

年代:1962

数据来源: WILEY

摘要:

SUMMARYEmulsified coconut oil was given by intraduodenal infusion to unanaesthetized, restrained rats, producing a steady state of fat absorption. The output of absorbed fat was measured by thoracic duct fistulae and, in other groups, disappearance of fat from the intestinal lumen and rate of movement along the small intestine of an unabsorbable, water miscible marker were measured by intestinal recoveries.Morphine, 32 mg./kg. in a single dose intraduodenally, decreased lymph flow, lymphatic output of fat and removal from the intestinal lumen. This was due to regurgitation of fat into the stomach by intestinal spasm, but intestinal absorption itself was not affected. Atropine, 1·0 mg./kg./hr. added to the infusion, diminished motility and slowed propulsion but had no consistent effect on absorption. By different mechanisms, both drugs slowed passage through the proximal small intestine and more fat was absorbed proximally than in normal rats.

ISSN:0004-945X    

DOI:10.1038/icb.1962.26

出版商:Nature Publishing Group    

年代:1962

数据来源: WILEY

摘要:

SUMMARYBy prenatal administration of embryonic spleen cells, chickens can be rendered tolerant in the sense that their circulating leucocytes are incapable of producing focal lesions on the chorioallantoic membranes of embryos of genotypes corresponding to those of the cell donors.In most of the experiments reported the extent of tolerance diminished rapidly as the birds grew older but in some of the pure line chickens persisting tolerance suggests that on occasion the effect may last indefinitely. The significance of antigenic specificity in the Simonsen reaction is briefly discussed.

ISSN:0004-945X    

DOI:10.1038/icb.1962.27

出版商:Nature Publishing Group    

年代:1962

数据来源: WILEY

摘要:

SUMMARYThe prior administration of the antioxidants α‐tocopherol acetate, sodium selenite or NN1‐diphenyl‐p‐phenylenediamine (DPPD) afforded protection to rats given lethal doses of carbon tetrachloride.Under the experimental conditions DPPD appeared to be the most effective of the three antioxidants tested. A single dose of 100 mg. DPPD injected intraperitoneally at the same time as CCl4was administered by stomach tube proved more effective than one dose of 95 international units of vitamin E given simultaneously with CCl4, or than a dose of 95 I.U. given simultaneously and another five hours later. Sodium selenite was less effective than the other two antioxidants.When antioxidants were given, pyridine nucleotide concentrations in the liver were maintained despite the subsequent administration of CCl4., but in their absence concentrations of both oxidized and reduced pyridine nucleotides in the liver fell by more than 50 p.c. The loss of reduced pyridine nucleotides was completely prevented by DPPD, the only antioxidant studied in this regard, and the loss of oxidized pyridine nueleotides was largely prevented by DPPD or α‐tocopherol acetate and to a lesser degree by sodium selenite.Three doses of 100 mg. DPPD at 48, 24 and 0 hours before rats were given 4 ml. CCl4/kg. prevented necrosis of liver cells and diminished the fatty change appreciably. A single dose of 100 mg. DPPD injected intraperitoneally 48 hours before 4 ml. CCl4/kg. also largely prevented hepatic necrosis and decreased the fatty change.

ISSN:0004-945X    

DOI:10.1038/icb.1962.28

出版商:Nature Publishing Group    

年代:1962

数据来源: WILEY