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排序方式: 共有1107条查询结果,搜索用时 250 毫秒
121.
Two new species of Stenoloba Staudinger, 1892 are described: S. ronkayi Sohn and Tzuoo sp. nov. from Taiwan and S. hystrix Sohn sp. nov. from northern Vietnam. The relationships of the new species with the actual species groups of Stenoloba are discussed. The formerly unknown female of S. nora Kononenko and Ronkay, 2001 and its genitalia are described here for the first time. 相似文献
122.
KIOM-79 is an herbal mixture of parched Puerariae radix, gingered Magnoliae cortex, Glycyrrhizae radix and Euphorbiae radix. In the present study, we determined the efficacy and possible mechanism of KIOM-79 on the advanced glycation end product (AGE)-modified bovine serum albumin (BSA)-induced apoptosis of cultured bovine retinal pericytes and rat retinal pericytes in Zucker diabetic fatty (ZDF) rats. Seven-week-old male ZDF rats were treated with KIOM-79 (50 mg/kg body weight) once a day orally for 13 weeks. KIOM-79 significantly inhibited pericyte apoptosis which were induced by the AGE-BSA treatment. The KIOM-79 treatment markedly suppressed the activation of nuclear factor-kappaB (NF-κB) through the inhibition of inhibitory κB kinase complex. In addition, the oral administration of KIOM-79 inhibited the changes in retinal vasculature (vascular hyperpermeability, acellular capillary). KIOM-79 strongly inhibited pericyte apoptosis, NF-κB activation and the expression of pro-apoptotic Bax and tumor necrosis factor-α. Our results suggest that KIOM-79 may exert inhibitory effects on AGE-induced pericyte apoptosis by blocking NF-κB activation, thereby ameliorating retinal microvascular dysfunction. 相似文献
123.
Sonya B Dumanis Kelly A Chamberlain Yoo Jin Sohn Young Jin Lee Suzanne Y Guénette Toshiharu Suzuki Paul M Mathews Daniel TS Pak G William Rebeck Yoo-hun Suh Hee-Sae Park Hyang-Sook Hoe 《Molecular neurodegeneration》2012,7(1):1-15
Background
Loss-of-function mutations in PTEN-induced kinase 1 (PINK1) have been linked to familial Parkinson??s disease, but the underlying pathogenic mechanism remains unclear. We previously reported that loss of PINK1 impairs mitochondrial respiratory activity in mouse brains.Results
In this study, we investigate how loss of PINK1 impairs mitochondrial respiration using cultured primary fibroblasts and neurons. We found that intact mitochondria in PINK1?/? cells recapitulate the respiratory defect in isolated mitochondria from PINK1?/? mouse brains, suggesting that these PINK1?/? cells are a valid experimental system to study the underlying mechanisms. Enzymatic activities of the electron transport system complexes are normal in PINK1?/? cells, but mitochondrial transmembrane potential is reduced. Interestingly, the opening of the mitochondrial permeability transition pore (mPTP) is increased in PINK1?/? cells, and this genotypic difference between PINK1?/? and control cells is eliminated by agonists or inhibitors of the mPTP. Furthermore, inhibition of mPTP opening rescues the defects in transmembrane potential and respiration in PINK1?/? cells. Consistent with our earlier findings in mouse brains, mitochondrial morphology is similar between PINK1?/? and wild-type cells, indicating that the observed mitochondrial functional defects are not due to morphological changes. Following FCCP treatment, calcium increases in the cytosol are higher in PINK1?/? compared to wild-type cells, suggesting that intra-mitochondrial calcium concentration is higher in the absence of PINK1.Conclusions
Our findings show that loss of PINK1 causes selective increases in mPTP opening and mitochondrial calcium, and that the excessive mPTP opening may underlie the mitochondrial functional defects observed in PINK1?/? cells. 相似文献124.
Yeom JS Kim ES Lim KJ Oh JH Sohn MJ Yoo SB Kim E Bae I Jung YJ Park JW 《The Journal of parasitology》2008,94(6):1410-1414
The antibody levels against the C-terminal region of the merozoite surface protein 1 of Plasmodium vivax (PvMSP1c) were measured in 276 patients with P. vivax malaria (patient group), 320 malaria-na?ve healthy individuals (control group 1), and 70 malaria-na?ve individuals with various disorders (control group 2) using the immunoglobulin M (IgM) capture enzyme-linked immunosorbent assay (ELISA) and the direct sandwich ELISA. To evaluate the antibody response during relapse, 5 relapsed patients were tested using the IgM capture ELISA. The IgM antibodies were negative in 99.7% of control group 1 and in 100% of control group 2; they were positive in 90.6% of the patient group. The total antibody levels were positive in 88.4% of the patient group with the direct sandwich ELISA. The sera from the second malaria episode, i.e., relapsed patients, were 100% positive on the IgM capture ELISA. The results of this study suggest that the IgM capture ELISA may be a useful diagnostic method for P. vivax malaria for both primary infection and relapse. 相似文献
125.
The FcgammaRIIB is a potent regulator of BCR signaling and as such plays a decisive role in controlling autoimmunity. The use of advanced imaging technologies has provided evidence that the earliest events in Ag-induced BCR signaling include the clustering of the BCR, the selective and transient association of the clustered BCR with raft lipids, and the concentration of BCR clusters in an immune synapse. That lipid rafts play a role in FcgammaRIIB's regulation of BCR signaling was suggested by recent studies showing that a lupus-associated loss of function mutation resulted in the receptor's exclusion from lipid rafts and the failure to regulate BCR signaling. In this study, we provide evidence from both biochemical analyses and fluorescence resonance energy transfer in conjunction with both confocal and total internal reflection microscopy in living cells that the FcgammaRIIB, when coligated with the BCR, associates with lipid rafts and functions both to destabilize the association of the BCR with raft lipids and to block the subsequent formation of the B cell's immune synapse. These results define new early targets of FcgammaRIIB inhibitory activity in the Ag-induced B cell activation pathway. 相似文献
126.
Experimental and computational studies of strain-conduction velocity relationships in cardiac tissue 总被引:1,自引:1,他引:0
McNary TG Sohn K Taccardi B Sachse FB 《Progress in biophysics and molecular biology》2008,97(2-3):383-400
Velocity of electrical conduction in cardiac tissue is a function of mechanical strain. Although strain-modulated velocity is a well established finding in experimental cardiology, its underlying mechanisms are not well understood. In this work, we summarized potential factors contributing to strain-velocity relationships and reviewed related experimental and computational studies. We presented results from our experimental studies on rabbit papillary muscle, which supported a biphasic relationship of strain and velocity under uni-axial straining conditions. In the low strain range, the strain-velocity relationship was positive. Conduction velocity peaked with 0.59 m/s at 100% strain corresponding to maximal force development. In the high strain range, the relationship was negative. Conduction was reversibly blocked at 118+/-1.8% strain. Reversible block occurred also in the presence of streptomycin. Furthermore, our studies revealed a moderate hysteresis of conduction velocity, which was reduced by streptomycin. We reconstructed several features of the strain-velocity relationship in a computational study with a myocyte strand. The modeling included strain-modulation of intracellular conductivity and stretch-activated cation non-selective ion channels. The computational study supported our hypotheses, that the positive strain-velocity relationship at low strain is caused by strain-modulation of intracellular conductivity and the negative relationship at high strain results from activity of stretch-activated channels. Conduction block was not reconstructed in our computational studies. We concluded this work by sketching a hypothesis for strain-modulation of conduction and conduction block in papillary muscle. We suggest that this hypothesis can also explain uni-axially measured strain-conduction velocity relationships in other types of cardiac tissue, but apparently necessitates adjustments to reconstruct pressure or volume related changes of velocity in atria and ventricles. 相似文献
127.
Cloning endangered gray wolves (Canis lupus) from somatic cells collected postmortem 总被引:3,自引:0,他引:3
Oh HJ Kim MK Jang G Kim HJ Hong SG Park JE Park K Park C Sohn SH Kim DY Shin NS Lee BC 《Theriogenology》2008,70(4):638-647
The objective of the present study was to investigate whether nuclear transfer of postmortem wolf somatic cells into enucleated dog oocytes, is a feasible method to produce a cloned wolf. In vivo-matured oocytes (from domestic dogs) were enucleated and fused with somatic cells derived from culture of tissue obtained from a male gray wolf 6h after death. The reconstructed embryos were activated and transferred into the oviducts of naturally synchronous domestic bitches. Overall, 372 reconstructed embryos were transferred to 17 recipient dogs; four recipients (23.5%) were confirmed pregnant (ultrasonographically) 23-25 d after embryo transfer. One recipient spontaneously delivered two dead pups and three recipients delivered, by cesarean section, four cloned wolf pups, weighing 450, 190, 300, and 490g, respectively. The pup that weighed 190g died within 12h after birth. The six cloned wolf pups were genetically identical to the donor wolf, and their mitochondrial DNA originated from the oocyte donors. The three live wolf pups had a normal wolf karyotype (78, XY), and the amount of telomeric DNA, assessed by quantitative fluorescence in situ hybridization, was similar to, or lower than, that of the nuclear donor. In conclusion, the present study demonstrated the successful cloning of an endangered male gray wolf via interspecies transfer of somatic cells, isolated postmortem from a wolf, and transferred into enucleated dog oocytes. Therefore, somatic cell nuclear transfer has potential for preservation of canine species in extreme situations, including sudden death. 相似文献
128.
129.
Antigen binding to the B cell receptors (BCRs) induces BCR clustering, phosphorylation of BCRs by the Src family kinase Lyn, initiation of signaling, and formation of an immune synapse. We investigated B cells as they first encountered antigen on a membrane using live cell high resolution total internal reflection fluorescence microscopy in conjunction with fluorescence resonance energy transfer. Newly formed BCR microclusters perturb the local membrane microenvironment, leading to association with a lipid raft probe. This early event is BCR intrinsic and independent of BCR signaling. Association of BCR microclusters with membrane-tethered Lyn depends on Lyn activity and persists as microclusters accumulate and form an immune synapse. Membrane perturbation and BCR-Lyn association correlate both temporally and spatially with the transition of microclustered BCRs from a "closed" to an "open" active signaling conformation. Visualization and analysis of the earliest events in BCR signaling highlight the importance of the membrane microenvironment for formation of BCR-Lyn complexes and the B cell immune synapse. 相似文献
130.
Jun YJ Min JH Ji da E Yoo JH Kim JH Lee HJ Jeong B Sohn YS 《Bioorganic & medicinal chemistry letters》2008,18(24):6410-6413
A novel water soluble and biodegradable cyclotriphosphazene-paclitaxel conjugate was prepared by reacting 2'-succinyl paclitaxel with cyclotriphosphazenes bearing equimolar glycyl-L-lysine and methoxy poly(ethylene glycol) as side groups. The macromolecular conjugate was found to self-assemble in aqueous solution to form stable micelles with a mean hydrodynamic diameter of 24.7 nm and a low critical micelle concentration of 10 mg/L. The present conjugate exhibited lower than free paclitaxel but reasonably high in vitro cytotoxicity against selected human tumor cells due to their hydrolytic degradation in PBS solution. 相似文献