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991.
Insights into the function of Rim protein in photoreceptors and etiology of Stargardt's disease from the phenotype in abcr knockout mice. 总被引:19,自引:0,他引:19
Rim protein (RmP) is an ABC transporter of unknown function in rod outer segment discs. The human gene for RmP (ABCR) is affected in several recessive retinal degenerations. Here, we characterize the ocular phenotype in abcr knockout mice. Mice lacking RmP show delayed dark adaptation, increased all-trans-retinaldehyde (all-trans-RAL) following light exposure, elevated phosphatidylethanolamine (PE) in outer segments, accumulation of the protonated Schiff base complex of all-trans-RAL and PE (N-retinylidene-PE), and striking deposition of a major lipofuscin fluorophore (A2-E) in retinal pigment epithelium (RPE). These data suggest that RmP functions as an outwardly directed flippase for N-retinylidene-PE. Delayed dark adaptation is likely due to accumulation in discs of the noncovalent complex between opsin and all-trans-RAL. Finally, ABCR-mediated retinal degeneration may result from "poisoning" of the RPE due to A2-E accumulation, with secondary photoreceptor degeneration due to loss of the RPE support role. 相似文献
992.
Two different Nd(NO3)3-galactitol complexes, 2Nd(NO3)3.C6H14O6.8 H2O and Nd(NO3)3.C6H14O6 have been obtained and were characterized by FT-IR and X-ray diffraction techniques. The spectral differences of the two complexes were consistent with the crystal-structure data. 相似文献
993.
Shih S Weng YM Chen S Huang SL Huang CH Chen W 《Archives of biochemistry and biophysics》2003,420(1):79-86
FT-Raman spectroscopy was employed to explore the structural changes of lens proteins in Tilapia lenses affected by dietary vitamin E supplementation. The microenvironment of major lens constituents including thiol compounds, tyrosine, and tryptophan exhibited significant change upon vitamin E treatment, while the protein secondary structure was unaltered and remained as an antiparallel beta-pleated sheet. These structures in the cortex were more susceptible to vitamin E treatment than in the nucleus. Protein sulfhydryls in the cortex were predominantly in the reduced form, while in the nucleus both the oxidized and reduced forms coexisted as evidenced by the vibrational mode of SH (2580 cm(-1)) and SS (507 cm(-1)), respectively. Both tyrosine and tryptophan were more accessible to water or more exposed in the cortex than in the nucleus. The symmetrically inverse response of vitamin E, between Raman intensity of 1090 cm(-1) and the glutathione level, was consistent with a close relationship of GSH and vitamin E in defending the lens from external insults. 相似文献
994.
Direct EPR evidence of the photo-generation of superoxide radicals (O2
–.) was obtained by using a novel spin trapping probe in spinach Photosystem II (PS II) membrane fragments. The production of O2
–. was detected by following the formation of 5-diethoxyphosphoryl-5-methyl-1-pyrroline-N-oxide (DEPMPO) superoxide adducts (DEPMPO-OOH). The inhibition of O2
–. formation by 3-(3,4-dichlorophenyl) -1,1-dimethylurea (DCMU) and the 77 K fluorescence spectrum indicated that O2
–. were generated from PS II, not from PS I. The inhibition of O2
–. formation by DCMU also suggested that O2
–. were generated from the QBbinding site, not at a site prior to DCMU blockage. The extrinsic proteins and Mn are very important to eliminate O2
–., showing that the oxygen-evolving system is involved in O2
–. removal rather than production.This revised version was published online in October 2005 with corrections to the Cover Date. 相似文献
995.
Lai YL Yu YL Centeno RF Weng CJ 《Plastic and reconstructive surgery》2003,112(1):302-8; discussion 309-11
Since the 1980s, many patients have benefited from the use of the transverse rectus abdominis musculocutaneous (TRAM) flap for postmastectomy reconstruction. In addition to cancer reconstruction, this technique has recently been used to treat patients with breast implant intolerance and for reconstruction after siliconoma resection. However, physicians and patients alike believe that such an extensive procedure should not be used for aesthetic purposes, and to the authors' knowledge, no study has been reported on the use of pedicled TRAM flaps for aesthetic augmentation mammaplasty. In the past several years, a number of the authors' patients have requested simultaneous breast augmentation and abdominoplasty. These patients objected to the use of prosthetic implants because of potential complications such as implant failure, capsular contracture, wrinkling, and palpability. Therefore, from 1995 to 2000, the authors performed 14 cases of bilateral breast augmentation with deepithelialized, pedicled TRAM flaps. In this series, the donor-site complication rate was similar to that of the traditional TRAM flap. Surprisingly, no cases of complete or partial flap loss were clinically detected. The only complaints were pedicle bulges at the costal margins. These patients were all extremely satisfied with the results. It was concluded that the TRAM flap is safe for augmentation in a subset of carefully selected women with hypoplastic or atrophic breasts. The authors discuss patient selection, technique, and their experience with this method of breast augmentation. 相似文献
996.
Weng L Van Bockstaele DR Wauters J Van Marck E Plum J Berneman ZN Merregaert J 《The Journal of biological chemistry》2003,278(21):19164-19170
Chondrolectin (CHODL) is a novel type I transmembrane protein containing one carbohydrate recognition domain (CRD) of C-type lectins. Recently, data base searching revealed a variant of CHODL (AK022689) with a different 5' leader sequence derived from a new putative upstream alternative promoter (P2). The P2 promoter gives rise to at least three additional alternatively spliced isoforms, designated as CHODLf, CHODLf Delta E, and CHODL Delta E. Of all variants, the alternative exon E-splicing isoforms (CHODLf Delta E/CHODL Delta E) are expressed exclusively in the T lymphocyte lineage and are regulated during T lymphopoiesis. Peripheral T lymphocytes demonstrated a unique exon E-splicing pattern in comparison with end maturation stage thymocytes, suggesting its association with the post-thymic maturation of T cells. Since exon E encodes the transmembrane domain of CHODL, the exon E-skipping variant results in a non-transmembrane domain-containing isoform (CHODLf Delta E/CHODL Delta E) terminating in the QDEL sequence, thus suggesting different functional attributes of CHODL isoforms during the development of T cells. Double label immunofluoresence experiments demonstrated that the transmembrane-containing isoform (CHODLf) colocalizes with rBet1 to the endoplasmic reticulum-Golgi apparatus. In summary, this study describes the molecular characterization of novel members of the chondrolectin family associated with T cell maturation and a subcellular localization of CHODLf in the endoplasmic reticulum-Golgi apparatus. 相似文献
997.
998.
Eerkes A Addison T Naidong W 《Journal of chromatography. B, Analytical technologies in the biomedical and life sciences》2002,768(2):277-284
A liquid chromatography-tandem mass spectrometry method was developed for the analysis of sildenafil (SIL) and its metabolite desmethylsildenafil (DMS) in human plasma. Samples were accurately transferred to 96-well plates using a liquid handler (Multiprobe II). Solid-phase extraction was carried out on a 96-channel programmable liquid handling workstation (Quadra 96) using a C8 and cation-exchange mixed-mode sorbent. The extract was injected onto a silica column with an aqueous-organic mobile phase, a combination that was novel for improving the method sensitivity. The low limit of quantitation was 1.0 ng/ml for both SIL and DMS. The method was validated to meet the criteria of current industrial guidance for quantitative bioanalytical methods. 相似文献
999.
Weng Q Xia F Jin W 《Journal of chromatography. B, Analytical technologies in the biomedical and life sciences》2002,779(2):347-352
Capillary zone electrophoresis was employed for the analysis of histamine in single rat peritoneal mast cells using an amperometric detector with a carbon fiber microdisk bundle electrode. In this method, individual mast cells and then 0.02 mol/l NaOH as a lysing solution are injected into the front end of the separation capillary by electromigration with an aid of a inverted microscope. A cell injector was constructed. Using it, the cell suspension was static, when a voltage for injecting single cells was applied. Histamine in single rat peritoneal mast cells have been identified. Quantitation has been accomplished through the use of calibration curves. The mean amount of histamine for nine cells is 95.8 fmol, which is consistent with the literature value. 相似文献
1000.
Wright P Anderson P Weng L Frick N Wong WP Ip YK 《Journal of experimental zoology. Part A, Comparative experimental biology》2004,301(7):559-568
The crab-eating frog Rana cancrivora is one of only a handful of amphibians worldwide that tolerate saline waters. They typically inhabit brackish water of mangrove forests of Southeast Asia, but live happily in freshwater and can be acclimated to 75% seawater (25 ppt) or higher. We report here that after transfer of juvenile R. cancrivora from freshwater (1 ppt) to brackish water (10 -->20 or 20 -->25 ppt; 4-8 d) there was a significant increase in the specific activity of the key hepatic ornithine urea cycle enzyme (OUC), carbamoyl phosphate synthetase I (CPSase I). At 20 ppt, plasma, liver and muscle urea levels increased by 22-, 21-, and 11-fold, respectively. As well, muscle total amino acid levels were significantly elevated by 6-fold, with the largest changes occurring in glycine and beta-alanine levels. In liver, taurine levels were 5-fold higher in frogs acclimated to 20 ppt. There were no significant changes in urea or ammonia excretion rates to the environment. As well, the rate of urea influx (J(in) (urea)) and efflux (J(out) (urea)) across the ventral pelvic skin did not differ between frogs acclimated to 1 versus 20 ppt. Taken together, these findings suggest that acclimation to saline water involves the up-regulation of hepatic urea synthesis, which in turn contributes to the dramatic rise in tissue urea levels. The lack of change in urea excretion rates, despite the large increase in tissue-to-water gradients further indicates that mechanisms must be in place to prevent excessive loss of urea in saline waters, but these mechanisms do not include cutaneous urea uptake. Also, amino acid accumulation may contribute to an overall rise in the osmolarity of the muscle tissue, but relative to urea, the contribution is small. 相似文献