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91.
Takeda S.; Wu E. Y.; Epstein R. H.; Estrera A. S.; Hsia C. C.W. 《Journal of applied physiology》1997,82(4):1340-1348
Takeda, S., E. Y. Wu, R. H. Epstein, A. S. Estrera, and C. C. W. Hsia. In vivo assessment of changes in air and tissue volumes after pneumonectomy. J. Appl.Physiol. 82(4): 1340-1348, 1997.We examined theprogression and topographical distribution of postpneumonectomy volumechanges in immature foxhounds undergoing right pneumonectomy (R-Pnx,n = 5) or sham pneumonectomy (Sham, n = 6) at 2 mo of age and subsequentlyraised to maturity. Volumes of lung air (Vair) and tissue(Vti) were estimated by computerized tomography (CT) scan at 7, 22, and52 wk after surgery at a transpulmonary pressure of 20 cmH2O. Estimates of Vti by CT scanincluded both septal tissue as well as nonseptal tissue (small- andmedium-sized airways and blood vessels); these were compared withestimates of septal Vti by an acetylene rebreathing (Rb) method. Wefound significant correlations between these techniques(VairCT = 0.83 VairRb + 275, R = 0.97;VtiCT = 1.62 VtiRb 30, R = 0.81). Extravascular septal Vtireturned to normal 7 wk after R-Pnx and remained normal up to maturity.Nonseptal Vti remained significantly below normal. The greatestincrease in Vti occurred in the midlung region just cephalad and caudalto the heart. After an early period of accelerated tissue growth afterR-Pnx, the rate of septal tissue growth matched that of somatic growth,whereas nonseptal tissue growth lagged behind. Compensatory growth ofthe remaining left lung was not associated with selectivealterations in thoracic development. 相似文献
92.
Precocene II (6,7-dimethoxy-2,2-dimethyl-2H-benzo[b]pyran), an insect growth regulator that is structurally related to several naturally occurring carcinogenic and non-carcinogenic alkenylbenzenes, is genotoxic and produces hepatic centrolobular necrosis in rats. This investigation was conducted to evaluate the effects of modulation of hepatic glutathione levels on the toxicity of precocene II. Administration of a toxic dose of precocene II (175 mg/kg) to male Sprague-Dawley rats rapidly depleted hepatic GSH, produced histopathological changes in the liver, and induced increases in serum aminotransferase activity. Concurrent administration of the cysteine pro-drug L-2-oxothiazolidine-4-carboxylic acid (OTC) prevented these toxic effects of precocene II. In contrast, pretreatment of rats with DL-buthionine-SR-sulfoximine (BSO), an inhibitor of glutathione synthesis, potentiated the toxicity of an otherwise non-toxic dose of precocene II (100 mg/kg). These results indicate that glutathione is important for protection from precocene II-induced hepatotoxicity. 相似文献
93.
94.
A D Purdon J C Hsia L Pinteric D O Tinker R P Rand 《Canadian journal of biochemistry》1975,53(2):196-206
Another publication (rand, R. P., Pangborn, W., Purdon, A. D., and Tinker, D. O.(1975) Can. j. Biochem. 53, 189-195) has established that lysolecithin and cholesterol interact to form an equimolar complex. We have investigated this complex using the techniques of electron spin resonance (e.s.r) and electronmicroscopy. By varying the cholesterol concentration with lysolecithin in both thin films and dispersions studied by these techniques, we have observed the interaction between lysolecithin and equimolar complex below 50 mol % cholesterol, and between crystalline cholesterol and equimolar complex above 50 mol % cholesterol. We have observed an interesting alteration in morphology by electron microscopy, and an isotropic to anisotropic spectral change using 3-dosylcholestane and 12-doxylstearic acid spin-labelled probes when the cholesterol concentration is increased from 20 to 33 mol %. The equimolar complex is stable in the presence of crystalline cholesterol, and exhibits no phase changes in the physiological temperature range. Implications for membrane structure are discussed. 相似文献
95.
Lipogenesis in vitro from acetate-1-(14)C was studied in human preputial skin and abdominal skin. Radioactive lipids were separated by column chromatography on Florisil and by thin-layer chromatography on silica gel. Radioactivity was incorporated chiefly into the triglyceride, sterol, and polar lipid fractions, while lesser amounts of (14)C were found in the hydrocarbon, wax, diglyceride, monoglyceride, and fatty acid fractions; labeling of steryl esters was minimal. On thin-layer chromatography, the radioactive polar lipids had mobilities similar to lysolecithin, phosphatidyl choline, phosphatidyl ethanolamine, and phosphatidic acid. The radioactive fatty acids of the different lipid fractions were separated by gas-liquid chromatography. The major (14)C-labeled acids were 16:0 and 18:0. Radioactivity was also detected in acids 14:0, 15:0, 16:1, 18:1, 18:2, 20:0, 20:1, 22:0, 24:0, 24:1, and 26:0. No radioactivity could be detected in arachidonic acid, although this fatty acid comprises 9% of the chromatographed fatty acids. The pattern of incorporated (14)C was different from the percentage mass composition of the fatty acids. Skin is therefore active in the biosynthesis of a wider variety of lipids than previously demonstrated. 相似文献
96.
Sequence of a cDNA for mouse thymidylate synthase reveals striking similarity with the prokaryotic enzyme 总被引:11,自引:0,他引:11
Perryman SM; Rossana C; Deng TL; Vanin EF; Johnson LF 《Molecular biology and evolution》1986,3(4):313-321
We report the nucleotide sequence of a cloned cDNA, pMTS-3, that contains a
1-kb insert corresponding to mouse thymidylate synthase (E.C. 2.1.1.45).
The open reading frame of 921 nucleotides from the first AUG to the
termination codon specifies a protein with a molecular mass of 34,962
daltons. The predicted amino acid sequence is 90% identical with that of
the human enzyme. The mouse sequence also has an extremely high degree of
similarity (as much as 55% identity) with prokaryotic thymidylate synthase
sequences, indicating that thymidylate synthase is among the most highly
conserved proteins studied to date. The similarity is especially pronounced
(as much as 80% identity) in the 44-amino-acid region encompassing the
binding site for deoxyuridylic acid. The cDNA sequence also suggests that
mouse thymidylate synthase mRNA lacks a 3' untranslated region, since the
termination codon, UAA, is followed immediately by a poly(A) segment.
相似文献
97.
Use of a low-speed,iso-density percoll centrifugation method to increase the viability of isolated rat hepatocyte preparations 总被引:23,自引:0,他引:23
Bill L. Kreamer Jeffrey L. Staecker Norimasa Sawada Gerald L. Sattler M. T. Stephen Hsia Henry C. Pitot 《In vitro cellular & developmental biology. Plant》1986,22(4):201-211
Summary A simple yet effective method (iso-density percoll centrifugation) has been developed for consistently preparing isolated
rat liver parenchymal cells with over 98% initial viability. The method has been applied to cells isolated by a variety of
collagenase digestion techniques. This procedure involves the low-speed centrifugation (50 ×g) of the initial cell suspension through a percoll medium having a density of 1.06 g/ml and results in the separation of single
and viable parenchymal cells from cell aggregates, debris, and nonparenchymal cells. The enriched parenchymal cells have been
shown to be superior to untreated cells by a number of criteria including: preparation homogeneity, cell morphology, maintenance
of cytochrome P-450, hormonal responsiveness (measured by the induction of tyrosine aminotransferase after treatment with
glucagon or dexamethasone, or both), plasma membrane integrity (determined by both trypan blue exclusion and leakage of glutamic-oxaloacetic
transaminase), and the DNA repair capability after treatment with benzo[a]pyrene or 2-acetylaminofluorene.
This work was supported in part by the National Institutes of Health Biomedical Research Support Program, and National Institute
of Environmental Health Services grant (ES-01737) awarded to M.T.S.H., and by National Cancer Institute grants CA-017175,
CA-09135, CA-22484 awarded to H.C.P.N.S. was supported by a Cancer Research Campaign Grant (U. K.) through the International
Union Against Cancer. This work was presented in part at the 24th Annual Meeting of the Society of Toxicology, 18–22 March
1985, San Diego, CA. 相似文献
98.
Sequence analysis has been performed on the DNA of 13 glucose-6-phosphate dehydrogenase (G6PD) deficient males from Hawaii, 6 of Filipino, 6 of Laotian, and 1 of Chinese extraction. Four different mutations were found: A-->T at cDNA nt 835, G-->A at nt 871, C-->T at nt 1360, and G-->A at nt 1388. The mutations at nt 835 and nt 1360 have not been described previously, and the latter, in particular, appears to be relatively common. The nt 1360 mutation changes the same codon as is altered in a previously described mutation, G6PD Andalus. 相似文献
99.
100.