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991.
IN Walters PF Teychenne LE Claveria DB Calne 《Canadian Metallurgical Quarterly》1976,26(11):1008-1010
The passage of penicillin G from cerebrospinal fluid (CSF) was studied by continuous ventriculocisternal perfusion in conscious rabbits. The concentration of penicillin G in the perfusate, collected from the cisterna magna, was 76.5 percent +/- 1.0 (SEM) of that entering the ventricles (having adjusted for normal secretion of CSF). The mean concentration of penicillin G rose 15 percent (p less than 0.005) in the cisternal CSF after probenecid (2 mg per milliliter) was added to the perfusion fluid. We conclude that an active transport system removes penicillin G from the CSF; this mechanism can be inhibited by intraventricular probenecid. Our results are in accord with observations deriving from studies on anesthetized animals given probenecid intravenously or intraperitoneally. 相似文献
992.
A radioimmunoassay is presented which employs 125I-labelled synthetic secretin, antibody against synthetic secretin, and standards prepared from pure natural porcine secretin. Secretin to be measured was extracted into methanol from heparinized plasma containing aprotinin, which together with cysteine hydrochloride was used as stabilizer throughout the assay. With polyethylene glycol separation, a within assay precision of 10% at 17 pmol/1 was found. The between assay precision was 15% at 17 pmol/1 and thelimit of detection 2.5 pmol/1 plasma. Accuracy was 70-85%. The immunoreactive secretin levels in human plasma increased from 4.5+/-0.5 pmol/1 (mean+/-S.E.M.) to 19.5+/-7.5 pmol/1 (mean+/-S.E.M.) after duodenal acidification (n=5). Pancreatic flow rate increased from 0.5+/-0.1 ml/min (mean+/-S.E.M.) to 4.8+/-0.5 ml/min (mean+/-S.E.M.), and bicarbonate output from 9.6+/-1.8 mumol/min (mean+/-S.E.M.) to 268+/-51 mumol/min (mean+/-S.E.M.) after duodenal acidification. 相似文献
993.
LE Ravdonikas 《Canadian Metallurgical Quarterly》1976,(12):29-32
S. typhimurium glycerine mutants-gly 90 and gly 87 were obtained under the action of ethylmethanesulfonate. The mutants obtained were characterized by the site of block in the course of glycerine utilization:gly 90 mutant bore the mutation in the glp K-gene, this leading to the defect by glycerokinase-the enzyme of the first stage of glycerine metabolism; gly 87 mutant had derangements in the other stage of glycerine utilization. Both mutants lost their capacity to induce keratoconjunctivitis in guinea pigs, but differed by the LD50 value in intraperitoneal infection of albino mice (y gly 87--5 cells, y gly 90--1x10(7) cells). 相似文献
994.
Effects of dietary myo-inositol deprivation were examined during prenatal and postnatal development and during lactation in the rat. The deficient diet contained no detectable myo-inositol while the supplemented diet contained 0.5% (w/w) myo-inositol while the supplemented diet ct contained 0.5% (w/w) myo-inositol at the expense of sucrose. Both diets contained 25% casein, adequate amounts of all known vitamins, choline, and essential fatty acids as well as 0.5% (w/w) phthalylsulfathiazole to depress myo-inositol contribution to the diet by microorganisms. Pregnant rats of the Holtzman strain were fed the respective diets during gestation and lactation, and pups were fed the corresponding diet after weaning until 3 months of age. There were no significant differen-es in body weight between experimental groups. Supplementation of the diet with myo-inositol significanly increased the levels of myo-inositol in plasma, liver, kidney, and intestine of pups at all ages examined, and significantly increased the levels of myo-inositol in the milk and mammary tissue during lactation. During lactation, the myo-inositol deprived dams developed severe fatty livers (31% w/w) characterized by diminished phosphatidyl-inositol (50%) and total phospholipid phosphorus (57%) levels as compared with controls. After weaning, the liver lipid content of the myo-inositol deprived dams returned to normal (4.5%). The data suggest that a possible threshold level of free myo-inositol (approximately 0.15 mumoles/g lipid-free tissue) was required to prevent fatty liver in lactating dams under these dietary conditions. Effects of the deficient diet on fertility were also examined. Based on sperm count and production of offspring, there were no differnences between the experimental and control males. Females of both groups showed equal ability to produce offspring. 相似文献
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996.
J. C. NEWMAN Jr . P. E. IRVING J. LIN D. D. LE 《Fatigue & Fracture of Engineering Materials & Structures》2006,29(11):949-958
Fatigue crack growth predictions have been made on a helicopter round‐robin crack configuration. The crack configuration was a small corner defect at the edge of a large central hole in a flanged plate made of 7010 aluminium alloy and the component was subjected to a simulated helicopter spectrum loading. The crack growth rate data and the stress‐intensity factor (K) solution for the crack configuration were provided in the round‐robin. The FASTRAN life‐prediction code was used to predict fatigue crack growth under various load histories on the aluminium alloy, such as Rotorix and Asterix, on both compact tension C(T) specimens and the complex crack configuration. A BEASY three‐dimensional stress‐intensity factor solution for the round‐robin problem was also provided for this paper and is compared with the original K solution. Comparisons are made between measured and predicted fatigue crack growth lives for both crack configurations. The predicted lives for the C(T) specimens were 15–30% longer than the measured lives; and crack growth in the round‐robin configuration agreed very well in the early stages of crack growth, but the life was 30% short of the test results at the final crack length. 相似文献
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