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31.
Deodorizing effects of tea catechins on amines were examined under alkaline conditions to eliminate the neutralization reaction. They showed deodorizing activity on ethylamine, but none on dimethylamine or trimethylamine. Deodorizing activity on ethylamine was found to be in the order of (-)-epigallocatechin gallate > gallic acid > (-)-epigallocatechin (EGC) > (-)-epicatechin gallate > ethyl gallate > (+)-catechin = (-)-epicatechin. Further, reaction products of EGC with methylamine, ethylamine, and ammonia were detected by HPLC, indicating that a deodorizing reaction other than neutralization occurs. From structural analysis of the reaction product with the methylamine isolated as a peracetylated derivative, the product was presumed to be methylamine substituted EGC, in which the hydroxyl group of EGC at the 4' position is replaced by the methylamino group. The same replacement reaction took place in the case of ethylamine and ammonia.  相似文献   
32.
To determine the genetic characteristics of the rabies virus in the Philippines, 59 rabies virus isolates were obtained from domestic rabid dogs and their partial nucleotide sequences of nucleoprotein (N) gene were compared. Based on comparison with reported sequences, phylogenetic analysis revealed that all isolates from the Philippines had close genetic relations and formed two subgroups. The Philippines isolates belonged to a different lineage from other Asian isolates but were closer to them than to terrestrial isolates and laboratory strains. Several specific nucleotide and amino acid substitutions were observed among the Philippines isolates. Our results suggest that rabies viruses in the Philippines might have a characteristic evolution.  相似文献   
33.
In Lambir Hills National Park, Sarawak, Malaysia, there are four species of processional termites that coexist: Hospitalitermes hospitalis, H. lividiceps, H. rufus and Longipeditermes longipes. This paper presents the results of our investigation on the spatial distribution of nests and the foraging activities of the four species in coexistence. The results show that there are fairly marked differences in nesting sites, as well as in foraging activities, among the four species. It is noteworthy that H. rufus inhabits only the canopy area over 20 m above ground, apparently segregated from the other three species, and that their foraging activities are limited also to tree canopies over 10 m above ground. In contrast, L. longipes nests underground and forages exclusively on the forest floor. Hospitalitermes hospitalis and H. lividiceps inhabit and forage over wide areas, from the forest floor to tree canopies. The upper parts of the tree canopy (over 10 m) are also foraging territories of the secluded H. rufus, but there were no observations of simultaneous foraging of the three Hospitalitermes species in the same canopy areas.  相似文献   
34.
Craniofacial development involves cranial neural crest (CNC) and mesoderm-derived cells. TGF-beta signaling plays a critical role in instructing CNC cells to form the craniofacial skeleton. However, it is not known how TGF-beta signaling regulates the fate of mesoderm-derived cells during craniofacial development. In this study, we show that occipital somites contribute to the caudal region of mammalian skull development. Conditional inactivation of Tgfbr2 in mesoderm-derived cells results in defects of the supraoccipital bone with meningoencephalocele and discontinuity of the neural arch of the C1 vertebra. At the cellular level, loss of TGF-beta signaling causes decreased chondrocyte proliferation and premature differentiation of cartilage to bone. Expression of Msx2, a critical factor in the formation of the dorsoventral axis, is diminished in the Tgfbr2 mutant. Significantly, overexpression of Msx2 in Myf5-Cre;Tgfbr2flox/flox mice partially rescues supraoccipital bone development. These results suggest that the TGF-beta/Msx2 signaling cascade is critical for development of the caudal region of the skull.  相似文献   
35.
Interactions between dendritic cells (DCs) and T cells play a pivotal role in the regulation and maintenance of immune responses. In cancer patients, various immunological abnormalities have been observed in these immune cells. Here, we investigated proportions and the phenotype of DCs and the cytokine profile of T-cell subsets in the peripheral blood of patients with squamous cell carcinoma of the head and neck (SCCHN), using multicolor flow cytometry. The percentage of myeloid (CD11c+), but not plasmacytoid (CD123+) DCs, was significantly lower (P<0.05) and expression of HLA-DR was significantly decreased in total and myeloid DCs of cancer patients compared to healthy donors. Simultaneous analyses of T-cell subsets in the patients’ circulation showed significantly increased proportions of CD4+ T cells expressing Th1 and Th2 cytokines after ex vivo stimulation without any skewing in the Th1/Th2 ratio. The relative level of HLA-DR expression on myeloid or total DCs positively correlated with the Th1/Th2 ratio (P<0.01), and the proportion of total circulating DCs was inversely correlated with that of regulatory CD4+CD25+ T cells (P<0.01). These results suggest that the decreased proportion of circulating DCs and decreased HLA-DR expression in DCs may have a major impact on systemic immune responses in patients with SCCHN.  相似文献   
36.
Nakano M  Kakehi K  Tsai MH  Lee YC 《Glycobiology》2004,14(5):431-441
We analyzed carbohydrate chains of human, bovine, sheep, and rat alpha1-acid glycoprotein (AGP) and found that carbohydrate chains of AGP of different animals showed quite distinct variations. Human AGP is a highly negatively charged acidic glycoprotein (pKa = 2.6; isoelectic point = 2.7) with a molecular weight of approximately 37,000 when examined by matrix-assisted laser-desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) and contains di-, tri-, and tetraantennary carbohydrate chains. Some of the tri- and tetraantennary carbohydrate chains are substituted with a fucose residue (sialyl Lewis x type structure). In sheep AGP, mono- and disialo-diantennary carbohydrate chains were abundant. Tri- and tetrasialo-triantennary carbohydrate chains were also present as minor oligosaccharides, and some of the sialic acid residues were substituted with N-glycolylneuraminic acid. In rat AGP, very complex mixtures of disialo-carbohydrate chains were observed. Complexity of the disialo-oligosaccharides was due to the presence of N, O-acetylneuraminic acids. Triantennary carbohydrate chains carrying N,O-acetylneuraminic acid were also observed as minor component oligosaccharides. We found some novel carbohydrate chains containing both N-acetylneuraminic acid and N-glycolylneuraminic acid in bovine AGP. Interestingly, triantennary carbohydrate chains were hardly detected in bovine AGP, but diantennary carbohydrate chains with tri- or tetrasialyl residues were abundant. Furthermore the major sialic acid in these carbohydrate chains was N-glycolylneuraminic acid. It should be noted that these sialic acids are attached to multiple sites of the core oligosaccharide and are not present as disialyl groups.  相似文献   
37.
Oxidative stress plays a pivotal role in chronic heart failure. SIRT1, an NAD+-dependent histone/protein deacetylase, promotes cell survival under oxidative stress when it is expressed in the nucleus. However, adult cardiomyocytes predominantly express SIRT1 in the cytoplasm, and its function has not been elucidated. The purpose of this study was to investigate the functional role of SIRT1 in the heart and the potential use of SIRT1 in therapy for heart failure. We investigated the subcellular localization of SIRT1 in cardiomyocytes and its impact on cell survival. SIRT1 accumulated in the nucleus of cardiomyocytes in the failing hearts of TO-2 hamsters, postmyocardial infarction rats, and a dilated cardiomyopathy patient but not in control healthy hearts. Nuclear but not cytoplasmic SIRT1-induced manganese superoxide dismutase (Mn-SOD), which was further enhanced by resveratrol, and increased the resistance of C2C12 myoblasts to oxidative stress. Resveratrol''s enhancement of Mn-SOD levels depended on the level of nuclear SIRT1, and it suppressed the cell death induced by antimycin A or angiotensin II. The cell-protective effects of nuclear SIRT1 or resveratrol were canceled by the Mn-SOD small interfering RNA or SIRT1 small interfering RNA. The oral administration of resveratrol to TO-2 hamsters increased Mn-SOD levels in cardiomyocytes, suppressed fibrosis, preserved cardiac function, and significantly improved survival. Thus, Mn-SOD induced by resveratrol via nuclear SIRT1 reduced oxidative stress and participated in cardiomyocyte protection. SIRT1 activators such as resveratrol could be novel therapeutic tools for the treatment of chronic heart failure.  相似文献   
38.
To evaluate the defence capacities of embryonic stem (ES) cells against gene impairment, this study measured the levels of 8-hydroxyguanine (8-OH-Gua), a well-known marker of oxidative stress in DNA, and its repair capacity during differentiation. Undifferentiated ES cells (EB3) were cultured without leukaemia inhibitory factor (LIF) for 0, 4 and 7 days and are referred to as ES-D0, ES-D4 and ES-D7, respectively. These three cell lines were treated with 300 μM hydrogen peroxide (H(2)O(2)) for 48 and 72 h. After treatment, the amounts of 8-OH-Gua in the cells were determined by the high-performance liquid chromatography (HPLC)-electrochemical detector (ECD) method. The levels of 8-OH-Gua in ES-D7 treated with H(2)O(2) were higher than those in ES-D0 and ES-D4, suggesting that the DNA in the undifferentiated cells was protected against gene impairment, as compared to that in the differentiated cells. To examine the repair capacity for 8-OH-Gua, this study analysed the expression of 8-OH-Gua repair-associated genes, 8-oxoguanine DNA glycosylase 1 (OGG1), MutY homolog (MUTYH) and Mut T homolog 1 (MTH1), in ES-D0, ES-D4 and ES-D7. The mRNA levels of MUTYH and MTH1 showed no significant change, whereas OGG1 mRNA was significantly decreased in ES-D7 treated with H(2)O(2). Moreover, it was observed that ES-D7 treated with H(2)O(2) readily underwent apoptosis, in comparison to its undifferentiated counterparts, ES-D0 and ES-D4. Taken together, ES cells are more resistant to DNA oxidative stresses than differentiated cells.  相似文献   
39.
Necdin is expressed predominantly in terminally differentiated neurons, and its ectopic expression suppresses cell proliferation. We screened a cDNA library from neurally differentiated embryonal carcinoma P19 cells for necdin-binding proteins by the yeast two-hybrid assay. One of the positive clones contained cDNA encoding a carboxyl-terminal portion of heterogeneous nuclear ribonucleoprotein U (hnRNP U), a nuclear matrix-associated protein that interacts with chromosomal DNA. We isolated cDNA encoding full-length mouse hnRNP U to analyze its physical and functional interactions with necdin. The necdin-binding site of hnRNP U was located near a carboxyl-terminal region that mediated the association between hnRNP U and the nuclear matrix. In postmitotic neurons, endogenously expressed necdin and hnRNP U were detected in the nuclear matrix and formed a stable complex. Ectopically expressed necdin was concentrated in the nucleoli, but coexpressed hnRNP U recruited necdin to the nucleoplasmic compartment of the nuclear matrix. Furthermore, under the same conditions necdin and hnRNP U cooperatively suppressed the colony formation of transfected SAOS-2 cells. These results suggest that necdin suppresses cell proliferation through its interaction with hnRNP U in the specific subnuclear structure.  相似文献   
40.

Objectives

To compare the optic nerve head (ONH) structure between compressive optic neuropathy (CON) and glaucomatous optic neuropathy (GON), and to determine whether selected ONH quantitative parameters effectively discriminate between GON and CON, especially CON cases presenting with a glaucoma-like disc.

Methods

We prospectively assessed 34 patients with CON, 34 age-matched patients with moderate or severe GON, and 34 age-matched healthy control subjects. The quantitative parameters of ONH structure were compared using the Heidelberg Retina Tomograph 2 (HRT2) and Spectralis optical coherence tomography with an enhanced depth imaging method.

Results

The mean and maximum cup depths of CON were significantly smaller than those with GON (P<0.001 and P<0.001, respectively). The distance between Bruch''s membrane opening and anterior surface of the lamina cribrosa (BMO-anterior LC) of CON was also significantly smaller than that of glaucoma but was similar to that of the healthy group (P<0.001 and P = 0.47, respectively). Based on Moorfields regression analysis of the glaucoma classification of HRT2, 15 eyes with CON were classified with a glaucoma-like disc. The cup/disc area ratio did not differ between cases of CON with a glaucoma-like disc and cases of GON (P = 0.16), but the BMO-anterior LC and mean and maximum cup depths of CON cases with a glaucoma-like disc were smaller than those in GON (P = 0.005, P = 0.003, and P = 0.001, respectively).

Conclusions

Measurements of the cup depths and the LC depth had good ability to differentiate between CON with a glaucoma-like disc and glaucoma. There was no laminar remodeling detected by laminar surface position in the patients with CON compared to those with GON.  相似文献   
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