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11.
12.
Lipid composition of the vascular system during infancy, childhood, and young adulthood 总被引:1,自引:0,他引:1
The object of this study was to determine the changes in lipid composition that occur in blood vessels from infancy to young adulthood. Analyses included levels of total cholesterol, total triglyceride, phospholipid, and cholesteryl ester fatty acids, and the distribution of saturated and unsaturated fatty acids. Triglyceride, total and monoenoic fatty acids, and linoleic acid were lower in the ascending, thoracic, and abdominal aorta than in the pulmonary artery and inferior vena cava. Phospholipids and arachidonic acid were higher in aortic segments than in the other two vessels. Aortic lipids showed significant changes with increasing age: total cholesterol and total fatty acids decreased from <1 wk to 5 yr, then increased to 22 yr of age. Triglycerides decreased whereas cholesteryl esters increased from 10 to 22 yr of age. Saturated fatty acids decreased from 1 wk to 10 yr, then remained relatively constant. Linoleic acid (3.7-9.8% of total fatty acids) and arachidonic acid (15.8-21.7%) both increased with age; the increase in cholesteryl linoleate was highly significant. After 10 yr of age, total cholesterol and total fatty acids were significantly higher in abdominal than in ascending and thoracic segments of aorta. 相似文献
13.
The two major forms of rabbit liver microsomal cytochrome P-450, P-450LM2 and P-450LM4, which were previously shown to differ in their absorption spectra, electrophoretic and immunochemical properties, and substrate specificities, have been further characterized by several methods, (a) The two cytochromes have different CD spectra in the ferric state but similar spectra when reduced. Upon conversion of P-450LM2 to P-420 by treatment with sodium dodecyl sulfate, the CD spectrum is greatly diminished except in the far ultraviolet region, whereas the conversion of P-450LM4 toP-420 with this detergent results in a spectrum with a new positive band in the visible region, (b) Although P-450LM4 has a much higher tryptophan content than P-450LM2, the fluorescence spectra of these proteins are similar in magnitude. Upon denaturation, the fluorescence of P-450LM4 increases, thereby indicating a large quenching effect in the native protein, (c) Studies on the interaction of dilauroylglyceryl-3-phosphorylcholine with the cytochromes showed that P-450LM2 gives a much stronger Type I difference spectrum than does P-450LM4. This phospholipid has no significant effect on the state of aggregation of these cytochromes as judged by calibrated gel filtration. The CD spectra of P-450LM2 and P-450LM4 are unchanged in the visible region but are enhanced in the far ultraviolet region upon the addition of phosphatidylcholine. The results appear to indicate an increase in α-helical content, particularly with P-450LM4, in the presence of the phospholipid. 相似文献
14.
We have expressed in Escherichia coli a cDNA encoding rabbit liver cytochrome P-450IIE1, the ethanol-inducible P-450. The expressed P-450 is located primarily in the bacterial inner cell membrane and comprises 3% of the E. coli total membrane protein. The partially purified cytochrome exhibits a reduced CO difference spectrum with a maximum at 452 nm, characteristic of P-450IIE1, and solubilized membranes or partially purified P-450 preparations reconstituted with NADPH-cytochrome P-450 reductase and phosphatidylcholine catalyze the deethylation of N-nitrosodiethylamine with a turnover number equal to that of purified liver P-450IIE1 (approximately 4.5 nmol/min/nmol of P-450). A modified IIE1 cDNA that encodes a protein lacking amino acids 3-29, a proposed membrane anchor for cytochrome P-450, was also expressed in E. coli and, unexpectedly, the shortened protein was also found to be predominantly located in the bacterial inner membrane rather than the cytosol. Like the full-length protein, this truncated cytochrome has a reduced CO difference spectrum characteristic of P-450IIE1 and is fully active in the deethylation of N-nitrosodiethylamine. These results demonstrate that the NH2-terminal hydrophobic segment is not solely responsible for attachment to the membrane and evidently is not required for proper protein folding or catalytic activity. 相似文献
15.
Galactose oxidase is a metalloenzyme containing a single copper atom per molecule. The mechanism of action of galactose oxidase is studied in this paper by investigating substrate specificity and activation by peroxidase, and probing the copper site by electron spin resonance (ESR) spectroscopy. Line-shape simulation of ESR spectra are also reported and a comparison is made between observed and simulated spectra for galactose oxidase. A comparison is also reported for the enzyme from various commercial sources and enzyme isolated from a fungus in this laboratory. The results of this investigation suggest that the copper is in an environment of four in-plane nitrogens with axial symmetry. 相似文献
16.
P G Zaphiropoulos W R Folk M J Coon 《Biochemical and biophysical research communications》1986,134(2):499-505
A rabbit liver P-450-like pseudogene has been isolated from a lambda phage genomic library. Sequence analysis revealed structural homology with respect to the rat P-450b and P-450e genes as well as a similar intron-exon organization. A 5'-proximal TATA box-like sequence and two 3'-distal putative polyadenylation signals were identified, and all putative intron-exon boundaries except at the 3'-splice site of intron 2 were found to follow the GT/AG rule. With allowance for apparent deletions and insertions, the structural homology of the amino acid sequence deduced from the pseudogene with respect to rabbit P-450 isozyme 2 is lower for exons 1 through 4 (18-28%) than for exons 5 through 9 (42-65%). S1 nuclease mapping showed that mRNAs complementary to the DNA sequence of exon 9 are expressed. However, due to the alterations in the pseudogene, it appears that functional P-450 would not be produced from such mRNAs. 相似文献
17.
18.
Tumor infiltrating lymphocytes (TIL), especially T-cells, have both prognostic and therapeutic applications. The presence of CD8+ effector T-cells and the ratio of CD8+ cells to FOXP3+ regulatory T-cells have been used as biomarkers of disease prognosis to predict response to various immunotherapies. Blocking the interaction between inhibitory receptors on T-cells and their ligands with therapeutic antibodies including atezolizumab, nivolumab, pembrolizumab and tremelimumab increases the immune response against cancer cells and has shown significant improvement in clinical benefits and survival in several different tumor types. The improved clinical outcome is presumed to be associated with a higher tumor infiltration; therefore, it is thought that more accurate methods for measuring the amount of TIL could assist prognosis and predict treatment response. We have developed and validated quantitative immunohistochemistry (IHC) assays for CD3, CD8 and FOXP3 for immunophenotyping T-lymphocytes in tumor tissue. Various types of formalin fixed, paraffin embedded (FFPE) tumor tissues were immunolabeled with anti-CD3, anti-CD8 and anti-FOXP3 antibodies using an IHC autostainer. The tumor area of stained tissues, including the invasive margin of the tumor, was scored by a pathologist (visual scoring) and by computer-based quantitative image analysis. Two image analysis scores were obtained for the staining of each biomarker: the percent positive cells in the tumor area and positive cells/mm2 tumor area. Comparison of visual vs. image analysis scoring methods using regression analysis showed high correlation and indicated that quantitative image analysis can be used to score the number of positive cells in IHC stained slides. To demonstrate that the IHC assays produce consistent results in normal daily testing, we evaluated the specificity, sensitivity and reproducibility of the IHC assays using both visual and image analysis scoring methods. We found that CD3, CD8 and FOXP3 IHC assays met the fit-for-purpose analytical acceptance validation criteria and that they can be used to support clinical studies. 相似文献
19.
Ricardo D. Ekmay Catalina Salas Judy England Sandro Cerrate Craig N. Coon 《Comparative biochemistry and physiology. Part B, Biochemistry & molecular biology》2013,164(1):38-43
A study was conducted to determine the changes that occur to proteolysis and related genes due to age, protein, and energy intake in high-yield broiler breeder hens (Gallus gallus). Cobb 700 broiler breeders were randomly assigned to one of six diets in a 2 × 3 factorial fashion. Two levels of energy (390 and 450 kcal/day) and three levels of protein (22, 24, and 26 g CP/day) were utilized. Protein turnover was determined in the left pectoralis at 22, 26, 31 and 44 weeks. Relative mRNA expression of calpain 2 (CAPN2), proteasome C2 subunit (PSMA1), and F box protein 32 (FBXO32) were determined via RT-PCR at 20, 25, and 44 weeks. Contrasts indicate fractional synthesis rate (FSR) and FBXO32 increase to a maximum at 25–26 weeks and a decrease thereafter. A significant drop in PSMA1 and FBXO32 was observed between 25 and 44 weeks and matched the decrease observed in FBR. No differences were detected in the levels of fractional synthesis and degradation, or the expression of CAPN2, PSMA1, and FBXO32, due to protein or energy intake. In summary, protein turnover was upregulated during the transition into sexual maturity and decreased thereafter. The observed changes in degradation appeared to be mediated by the ubiquitin–proteasome pathway. 相似文献
20.
Trey K. Sato Mary Tremaine Lucas S. Parreiras Alexander S. Hebert Kevin S. Myers Alan J. Higbee Maria Sardi Sean J. McIlwain Irene M. Ong Rebecca J. Breuer Ragothaman Avanasi Narasimhan Mick A. McGee Quinn Dickinson Alex La Reau Dan Xie Mingyuan Tian Jeff S. Piotrowski Jennifer L. Reed Yaoping Zhang Joshua J. Coon Chris Todd Hittinger Audrey P. Gasch Robert Landick 《PLoS genetics》2016,12(11)