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101.
Wu HC Lu TY Lee JJ Hwang JK Lin YJ Wang CK Lin CT 《Laboratory investigation; a journal of technical methods and pathology》2004,84(12):1547-1556
To understand whether the p53-regulated mdm2 gene expression was altered by the Epstein-Barr virus (EBV) in nasopharyngeal carcinoma (NPC), the NPC-TW01 cell line was infected by EBV through IgA receptor-mediated endocytosis. The mdm2 gene was expressed only in a small fraction of the NPC cell population and could be enhanced in the EBV-infected (EBV+) cells. In the animals bearing EBV+ and EBV- NPC xenografts, the MDM2+ cells only appeared in clusters in both EBV+ and EBV- tumors with stronger expression in EBV+ cells. Cotransfection of pmdm2-Luc plus pSV40-p53 plus pCMV-LMP1 in the NPC-TW06 line that had p53 heterozygous point mutation showed stronger mdm2 promoter activity than cells cotransfected with pmdm2-Luc plus pSV40-p53, but no mdm2 promoter activity was seen in cells cotransfected with pmdm2-Luc plus pCMV-LMP1. Only the EBV-LMP1 but not the EBV-LMP2A gene could enhance p53 to upregulated mdm2 expression. Tumor cells in NPC biopsy specimens revealed similar mdm2 expression as in the animal model. It is concluded that although EBV can indirectly enhance mdm2 gene expression in tumor cells that express this gene, it cannot turn on or directly regulate mdm2 expression in cells that do not express this gene. In other words, EBV plays a role as an enhancer in NPC tumorigenesis. 相似文献
102.
BACKGROUND: Forcipomyia taiwana is a tiny, blood-sucking midge that cause intense pruritis and swelling in sensitive individuals. It is distributed island-wide in rural Taiwan and Southern China. Objective: This study aimed to study the allergic immune responses and identify F. taiwana allergens. METHODS: Crude whole body F. taiwana extracts were prepared with phosphate-buffered saline. The specific IgE antibody was determined by enzyme-linked immunoassay and immunoblotting. Protein was analyzed by electrospray ionization tandem mass spectrometry. RESULTS: Among the 372 subjects that were exposed to F. taiwana bites, 179 (48%) reported an immediate skin reaction with/without delay reaction and 41(11.1%) reported a solely delay reaction. The skin of 21 subjects was tested with F. taiwana extract. Of these 21 subjects, 12 (57.1%) produced immediate skin reactions and contained high levels of specific IgE antibody against F. taiwana. Immunoblotting revealed that 11 allergenic components are able to bind specific IgE. Allergens of 22, 24, 35, 36, and 64 kDa bound 50, 50, 75, 66.7, and 75% of IgE-containing sera tested, respectively. Tryptic fragments of the 24, 35, 36, and 64 kDa allergens were analyzed by ESI-MS/MS. Selected tryptic peptides of 24, 35, and 36, and 64 kDa allergens exhibited significant sequence identity with triosephosphate isomerase of Anopheles merus,Tenebrio molitor,Ochlerotatus togoi, and Chrysops vittatus, fructose 1,6-bisphosphate aldolase of Antheraea yamamai and Homalodisca coagulata, and a slow muscle myosin S1 heavy chain of Homarusamericanus and a protein with unknown function from A. gambiae, respectively. The 35 and 36 kDa proteins may represent different isoforms of the fructose 1,6-bisphosphate aldolase. CONCLUSION: We conclude that immediate reaction to F. taiwana bites is IgE mediated and the 24 (For t 1), 35 (For t 2), and 64 kDa (For t 3) proteins are candidates for major F. taiwana allergens. Further studies are needed to confirm these allergens. 相似文献
103.
104.
Hwang IK Yoo KY Kim DW Han BH Kang TC Choi SY Kim JS Won MH 《Neuroscience letters》2005,375(2):117-122
We investigated the temporal and spatial alterations of protein disulfide isomerase (PDI) immunoreactivity and protein level in the hippocampus proper after 5 min transient forebrain ischemia in gerbils. PDI immunoreactivity was significantly altered in the hippocampal CA1 region. PDI immunoreactivity in the sham-operated animals was found in non-pyramidal cells. At 30 min after ischemia, PDI immunoreactivity was shown in the pyramidal cells of the stratum pyramidale (SP): the PDI immunoreactivity in the pyramidal cells was increased up to 12 h after ischemia. Thereafter PDI immunoreactivity was decreased, and the PDI immunoreactivity was shown in non-pyramidal cells 2 days after ischemia. Four to 5 days after ischemia, almost pyramidal cells in the CA1 region were lost because the delayed neuronal death occurred. At this time period, PDI immunoreactivity was expressed in some astrocytes as well as some neurons. The results of the Western blot analysis were consistent with the immunohistochemical data. These findings suggest that increase of PDI in pyramidal cells may play a critical role in resistance to ischemic damage at early time after ischemic insult, and that expression of this protein in astrocytes at late time after ischemic insult is partly implicated in the acquisition of tolerance against ischemic stress. 相似文献
105.
Hwang IK Yoo KY Kim DS Eum WS Park JK Park J Kwon OS Kang TC Choi SY Won MH 《Neuroscience》2004,128(3):511-518
In the previous study, we observed chronological alterations of glutamic acid decarboxylase (GAD), which is the enzyme converting glutamate into GABA. GAD isoforms (GAD65 and GAD67) differ substantially in their interactions with cofactor pyridoxal 5'-phosphate, which is catalyzed by pyridoxal kinase (PLK). In the present study, we examined the chronological changes of PLK expression and activity in the hippocampus after 5 min transient forebrain ischemia in gerbils. PLK immunoreactivity in the sham-operated group was detected weakly in the hippocampus. Ischemia-related change of PLK immunoreactivity in the hippocampus was significant in the hippocampal cornu ammonis (CA1)region, not in the hippocampal CA2/3 region and dentate gyrus. PLK immunoreactivity was observed in non-pyramidal GABAergic neurons at 30 min to 3 h after ischemic insult. At 12 h after ischemic insult, PLK immunoreactivity was shown in many CA1 pyramidal cells as well as some non-pyramidal cells. At this time point, PLK immunoreactivity and protein content was highest after ischemia. Thereafter, PLK immunoreactivity and protein content is decreased time-dependently by 4 days after ischemic insult. Four days after ischemia, some astrocytes expressed PLK in the CA1 region. The specific PLK activity was not altered following ischemic insult up to 2 days after ischemic insult. Thereafter, the specific PLK activity decreased time-dependently. However, total activity of PLK was significantly increased 12-24 h after ischemic insult, and thereafter total activity of PLK decreased. Therefore, we suggest that the over-expression of PLK in the CA1 pyramidal cells at 12 h after ischemia may induce increase of GAD in the CA1 pyramidal cells, which plays an important role in delayed neuronal death via the increase of GABA or enhancement of GABA shunt pathway. 相似文献
106.
Su SC Chou SS Chang PC Hwang DF 《Journal of chromatography. B, Biomedical sciences and applications》2000,749(2):163-169
A micellar electrokinetic capillary chromatography (MECC) method for the simultaneous determination of seven biogenic amines in fish was developed. The peaks of all components were successfully separated within 11.5 min. MECC was performed with 0.06 M sodium deoxycholate in 0.02 M borate buffer (pH 9.2)-methanol (95:5, v/v) solvent. The average recoveries for all components ranged from 84.4 to 100.3%. The application of this method to detect amines in fried marlin fillet implicated in a food poisoning incident indicated that a high level (56.24 mg/100 g) of histamine was present in the sample. Another 10 fish samples collected from markets were also analyzed and did not contain detectable levels of histamine (<2.5 mg/100 g). 相似文献
107.
108.
109.
Becker-Catania SG Chen G Hwang MJ Wang Z Sun X Sanal O Bernatowska-Matuszkiewicz E Chessa L Lee EY Gatti RA 《Molecular genetics and metabolism》2000,70(2):122-133
Previous studies on a limited number of ataxia-telangiectasia (A-T) patients with detectable levels of intracellular ATM protein have suggested a genotype/phenotype correlation. We sought to elucidate this possible correlation by comparing ATM protein levels with mutation types, radiosensitivity, and clinical phenotype. In this study, Western blot analysis was used to measure ATM protein in lysates of lymphoblastoid cell lines (LCLs) from 123 unrelated A-T patients, 10 A-T heterozygotes, and 10 patients with phenotypes similar to A-T. Our Western blot protocol can detect the presence of ATM protein in as little as 1 microg of total protein; at least 25 microg of protein was tested for each individual. ATM protein was absent in 105 of the 123 patients (85%); most of these patients had truncating mutations. The remaining subset of 18 patients (15%) had reduced levels of normal-sized ATM protein; missense mutations were more common in this subset. We used a colony survival assay to characterize the phenotypic response of the LCLs to radiation exposure; patients with or without detectable ATM protein were typically radiosensitive. Nine of 10 A-T heterozygotes also had reduced expression of ATM, indicating that both alleles contribute to ATM protein production. These data suggest that although ATM-specific mRNA is abundant in A-T cells, the abnormal ATM protein is unstable and is quickly targeted for degradation. We found little correlation between level of ATM protein and the type of underlying mutation, the clinical phenotype, or the radiophenotype. 相似文献
110.
Kim SN Rhee JH Song YH Park DY Hwang M Lee SL Kim JE Gim BS Yoon JH Kim YJ Kim-Ha J 《Neurobiology of aging》2005,26(7):1083-1091
Previous gene expression profiling studies in Drosophila have provided clues for understanding the aging process at the gene expression level. For a detailed understanding, studies of specific regions of the body are necessary. We therefore employed microarray analysis to examine gene expression changes in the Drosophila head during aging. Six hundred and eighty-four of the 5405 genes present in the microarray showed significant age-dependent changes as determined by significance analysis of microarray (SAM) (q < 0.05). The biological significance of the changes was analyzed using the gene annotations provided by the Gene Ontology Consortium. Major changes involved genes affecting energy metabolism (proton transport, energy pathways, oxidative phosphorylation) and neuronal function, especially responses to light. Genes involved in protein catabolism and several other metabolic processes also showed age-dependent changes. Most of the changes were reductions in gene expression and occurred before day 13 of adult life. After day 13, the age-dependent gene expression changes were relatively smaller than earlier life. Interestingly, the two biological processes of major gene expression changes are related to the two known environmental changes that increase life span in Drosophila: caloric restriction and light reduction. Our findings suggest that light signaling and energy metabolism may be important biological processes affected by aging and be interesting targets for the further investigation related to the longevity in Drosophila. 相似文献