Suicidal Ideation and Mental Health Help-Seeking Behaviors Among Older Chinese Adults During the COVID-19 Pandemic.

OBJECTIVE: To examine prevalence and correlates of suicidal ideation in older Chinese adults (OCAs) during the COVID-19 pandemic, as well as mental health help-seeking behaviors of suicidal OCAs. BACKGROUND: Few data on suicidal behaviors of older adults during the pandemic are available. METHODS: In this cross-sectional survey, 1159 OCAs completed an online self-administered questionnaire between 23 February and 25 March 2020. A standardized single question and the 12-item General Health Questionnaire were used to assess the presence of suicidal ideation and common mental health problems (CMHPs), respectively. Suicidal ideators were further asked about their perceived need for mental health care and help-seeking from mental health workers. RESULTS: 4.1% of the OCAs experienced suicidal ideation during the past 2 weeks. Among the suicidal OCAs, 31.9% perceived a need for mental health care but only 10.6% had sought help from mental health workers. Factors significantly associated with suicidal ideation were a marital status of "others" (OR=2.39, P = .021), disagreement regarding the successful containment of the pandemic (OR=2.43, P = .022), physical health problems (OR=2.23, P = .012), and CMHPs (OR=4.99, P < .001). CONCLUSIONS: During the COVID-19 pandemic, OCAs constitute a subpopulation that needs mental health services for suicidal problems but tends not to seek mental health help. Mental health services for OCAs may include mental health education, periodic evaluation of risk of suicide, expanded psychosocial support, and, when necessary, psychological crisis intervention and psychiatric treatment.

Hydroxy metabolites of polychlorinated biphenyls (OH-PCBs) exhibit inhibitory effects on UDP-glucuronosyltransferases (UGTs).

Hydroxy metabolites of polychlorinated biphenyls (OH-PCBs) are important substance basis for the toxicity of PCBs. This study aims to investigate the inhibition of OH-PCBs on the activity of UDP-glucuronosyltransferases (UGTs), trying to elucidate the toxicity mechanism of PCBs from a new perspective. In vitrohuman recombinant UGTs-catalyzed glucuronidation of 4-methylumbelliferone (4-MU) was used as the probe reaction. The number of chlorine atom can affect the inhibition potential of OH-PCBs towards different isoforms of UGTs, and complex structure-activity relationship was found for the inhibition of OH-PCBs on the activities of UGT isoforms. For the inhibition kinetic determination, 2'OHPCB106 and 4'OHPCB106 were selected as the representative OH-PCBs, and UGT1A1, 1A7, and 2B7 were chosen as the representative UGT isoforms. Competitive inhibition of 2'OHPCB106 and 4'OHPCB106 on the activities of UGT1A1, UGT1A7, and UGT2B7 was found. For 2'OHPCB106, the inhibition kinetic parameters (Ki) were calculated to be 0.4 µM for UGT1A1, 1.3 µM for UGT1A7, and 2.7 µM for UGT2B7, respectively. For 4'OHPCB106, Ki values were calculated to be 0.7 µM for UGT1A1, 6.8 µM for UGT1A7, and 4.8 µM for UGT2B7, respectively. In silico docking method was utilized to elucidate the inhibition difference of UGT1A1 by four OH-PCBs with similar structures (4'OHPCB9, 4'OHPCB26, 4'OHPCB112 and 4'OHPCB165). In conclusion, these data will be helpful for understanding the toxicity mechanisms of PCBs from a view of metabolic interference.

Characterization and Functional Identification of a Gene Encoding Geranylgeranyl Diphosphate Synthase from Dunaliella bardawil.

Geranylgeranyl diphosphate synthase (GGPS) catalyzes the biosynthesis of geranylgeranyl diphosphate, a key precursor for carotenoid biosynthesis. In this study, a full-length cDNA encoding GGPS from Dunaliella bardawil (DbGGPS) was isolated by rapid amplification of cDNA ends (RACE) for the first time. The full-length cDNA of DbGGPS was 1814 bp, containing a 1074 bp ORF encoding 357 amino acids with a calculated mass of 38.88 kDa. Analysis of DbGGPS genomic DNA revealed that it contained 10 exons and 9 introns. It was predicted that DbGGPS possessed a 48 amino acid transit peptide at its N terminus. Bioinformatic analysis revealed that DbGGPS was a member of a group of polyprenyltransferases with five conserved domains and two highly conserved aspartate-rich motifs. Using heterologous expression, carotenoid complementation assay, and gene deletion analysis, it was shown that the coding region of DbGGPS encodes a functional GGPS. This provides new gene sources for carotenoid genetic engineering.

Overexpression of NKX6.1 is closely associated with progressive features and predicts unfavorable prognosis in human primary hepatocellular carcinoma.

The homeobox gene NKX6.1 was recently identified in cervical tumors. This study was designed to explore the clinical and prognostic significance of NKX6.1 further in patients with primary hepatocellular carcinoma (HCC). The expression levels of NKX6.1 were examined using real-time PCR, Western blotting, and immunohistochemistry in HCC cell lines and HCC tissues. The invasion capability of cell lines following silencing or overexpression of NKX6.1 was investigated by Transwell assay. Cells proliferation was tested by MTT assays. Epithelial-mesenchymal transition (EMT) marker expression levels were detected in relation to NKX6.1 expression. Correlation between NKX6.1 immunohistochemical staining, clinicopathologic parameters, and follow-up data of HCC patients was analyzed statistically. NKX6.1 expression was higher in HCC tissues compared to the adjacent noncancerous tissue. NKX6.1 overexpression was significantly correlated with tumor size, tumor differentiation, clinical stage, metastasis, and relapse. Kaplan-Meier analysis revealed that NKX6.1 overexpression was related to unfavorable 5-year disease-free survival and overall survival. Importantly, multivariate analysis indicated that NKX6.1 overexpression was an independent unfavorable marker for overall survival. Moreover, a significant relationship was observed between NKX6.1 and EMT marker expression levels, and NKX6.1 knockdown inhibited cell invasion, and overexpression of NKX6.1 promotes cell proliferation in vitro. NKX6.1 is upregulated in HCC and is a reliable prognostic marker for patients with HCC.

Mutation breeding of Saccharomyces cerevisiae with lower methanol content and the effects of pectinase, cellulase and glycine in sugar cane spirits.

BACKGROUND: To decrease the methanol content of the sugar cane sprits, mutagenesis of ultraviolet (UV) coupled with diethyl sulfate (DES) was used to generate a mutant of Saccharomyces cerevisiae with lower methanol content. Meanwhile, the effects of the additions of pectinase, cellulase and glycine on the production of methanol in sugar cane spirits were evaluated. RESULTS: After mutagenesis of UV coupled with DES, a mutant S. cerevisiae DU9 with low production of methanol (97.3 ± 1.7 mg/L) was selected, with a 12.3% decrease of that of S. cerevisiae D4 only with DES treatment, and with a 27.8% reduction of that of the strain without any treatment. Pectinase and cellulase significantly increased the methanol levels of the sugar cane spirits. The results showed that there was linear relationship between glycine (concentration within 0∼0.9 g/L) and methanol in sugar cane sprits and the linear equation was y = 104.7 × -4.79 with the conversion rate of glycine conversion to methanol as 24.56%. CONCLUSION: Mutagenesis of UV coupled with DES is an efficient way to generate a mutant of S. cerevisiae with lower methanol content. Also, it is necessary to control the additions of pectinase, cellulase and glycine in the fermentation medium, and other unknown ways to generate methanol metabolic pathway in yeasts may need further study.

Reduction of methanol in brewed wine by the use of atmospheric and room-temperature plasma method and the combination optimization of malt with different adjuncts.

Methanol, often generated in brewed wine, is highly toxic for human health. To decrease the methanol content of the brewed wine, atmospheric and room-temperature plasma (ARTP) was used as a new mutagenesis tool to generate a mutant of Saccharomyces cerevisiae with lower methanol content. Headspace gas chromatography was used to determine the identity and concentration of methanol with butyl acetate as internal standard in brewed wine. With 47.4% higher and 26.3% positive mutation rates were obtained, the ARTP jet exhibited a strong effect on mutation breeding of S. cerevisiae. The mutant S. cerevisiae S12 exhibited the lowest methanol content, which was decreased by 72.54% compared with that of the wild-type strain. Subsequently, the mutant S. cerevisiae S12 was used to ferment different combinations of malt and adjuncts for lower methanol content and higher alcoholic content. It was shown that the culture 6#, which was 60% malt, 20% wheat, and 20% corn, was the best combinations of malt and adjuncts, with the lowest methanol content (104.8 mg/L), and a relatively higher alcoholic content (15.3%, v/v). The optimal malt-adjunct culture 6#, treated with the glucoamylase dose of 0.04 U/mg of grain released the highest reducing sugars (201.6 mg/mL). It was indicated that the variation in reducing sugars among the combinations of malt and different adjuncts could be due to the dose of exogenous enzymes.

The nucleotide polymorphisms within the Epstein-Barr virus C and Q promoters from nasopharyngeal carcinoma affect transcriptional activity in vitro.

Epstein-Barr virus (EBV) is a ubiquitous human gamma herpesvirus that is associated with Burkitt's lymphoma (BL), gastric carcinoma, nasopharyngeal carcinoma (NPC), and NK/T-cell lymphoma. Two viral promoters, Cp and Qp, are important for EBV latent infection. The latency Cp, which is used in primary infection, drives expression of the full spectrum of EBV nuclear antigens. Qp is active in EBV-associated tumors and drives the latency I/II expression pattern. In this study, we determined nucleotides polymorphisms in the Cp and Qp promoter regions in peripheral blood mononuclear cells (PBMCs) from Cantonese healthy carriers and in biopsies of NPC, nasal NK/T lymphoma, BL, and gastric carcinoma. The sequence changes of -12G>T and +69 C>T in Cp and -197 G>A and +1 G>C in Qp were frequently identified in NPC. Transient transfection studies using luciferase gene reporters revealed a significant reduction (57.11%) in gene expression from the Cp +69T variant and increased expression (43.5%) from the Qp +1C variant compared to the prototype, suggesting that these sequence variations affect promoter activity. Our results indicate that the nucleotides polymorphisms in Cp and Qp occur frequently in NPC and might contribute to the oncogenesis of EBV.

Fibrosis of pulmonary vascular remodeling in carotid artery-jugular vein shunt pulmonary artery hypertension model of rats.

OBJECTIVE: The aim of the present study was to observe the changes of hemodynamics, stereology in pulmonary vascular remodeling and messenger RNA (mRNA) expressions of transforming growth factor beta 1, and receptors in carotid artery-jugular vein (CA-JV) shunt pulmonary artery hypertension model of rats. METHODS: Thirty-six Sprague-Dawley rats were randomized into three groups: CA-JV group, monocrotaline (MCT) administration group, and control group. Left CA-JV shunts were established in CA-JV group. Dorsal subcutaneous injections of MCT (60 mg kg(-1)) were received in MCT group. Ligations of left common carotid artery and external jugular vein were performed in control group. Right ventricular systolic pressure (RVSP) measurement, histological evaluation of the pulmonary tissue, and mRNA levels of transforming growth factor beta 1 (TGFß1), receptor 1 and receptor 2, were investigated after 6 weeks on MCT group, and after 12 weeks on both control and CA-JV groups. RESULTS: Compared with control group, RVSP, percentage of fibrous tissue (F%) in pulmonary arterioles, mRNA levels of TGFß1, and receptors of CA-JVand MCT groups increased significantly. Severe hemodynamics change was found in MCT groups. On the other hand, CA-JV group demonstrated more obvious fibrogenesis and TGFß1 signals' upregulation in two pulmonary artery hypertension (PAH) models. CONCLUSIONS: CA-JV shunt model of rats was a well-established PAH animal model simulating congenital heart disease with systemic-pulmonary shunt.

[Effect of Epstein-Barr virus-encoded latent membrane protein 1 on ß-catenin transcriptional activity and expression in nasopharyngeal carcinoma].

OBJECTIVE: To investigate the contribution of latent membrane protein (LMP)1 to nasopharyngeal carcinogenesis via Wnt/ß-catenin signal pathway. METHODS: The recombinant plasmid pHA2-LMP1 was constructed; immunofluorescence staining, Dual-Luciferase Reporter Assay, Western blot and immunohistochemistry staining were used to study the effect of LMP1 on the transcriptional activity and expression of ß-catenin. RESULTS: (1) Abnormal expression of ß-catenin was obtained in 38 cases (50.7%, 38/75), LMP1 expression was obtained in 38 cases (50.7%, 38/75). There was significantly positive correlation between LMP1 expression and abnormal expression of ß-catenin in nasopharyngeal carcinoma tissue (P = 0.008). (2) The expression of ß-catenin in nuclei of NPC cell line CNE1 and CNE2 transfected with pHA2-LMP1 plasmid dramatically increased, and the expression was remarkable in poorly-differentiated NPC cell line CNE2 than that of well-differentiated CNE1 cells. (3) LMP1 expression dramatically increased the transcriptional activity of ß-catenin in CNE1 and CNE2 cells transfected with pHA2-LMP1 and was in a time-dependent. The transcriptional activity of ß-catenin was higher in poorly-defferentiated cell line CNE2 than that of well-differentiated NPC cell line CNE1. (4) LMP1 expression did not affect the total protein expression level of ß-catenin in both CNE1 and CNE2 cell lines. CONCLUSION: EB virus-encoded LMP1 may be involved in the pathogenesis of NPC via ß-catenin signal pathway.

Co-elevated expression of hepatocyte growth factor and Interleukin-8 contributes to poor prognosis of patients with primary nasopharyngeal carcinoma.

Hepatocyte growth factor (HGF) related tumor angiogenesis and prognosis of patients with nasopharyngeal carcinoma (NPC) has not been identified. The expressions of HGF and IL-8, as well as microvessels density were evaluated in 127 NPC biopsies by immunohistochemical staining. The correlation between these parameters and patient's clinicopathological features was analyzed statistically. In vitro, IL-8 concentration was evaluated in exogenous HGF-treated NPC cell lines by ELISA assay. The presence of EBV was also detected in NPC cells by PCR for Bam HI-W fragment. Both 54.3% (69/127) cases of HGF high-expression in tumor cells and 80.3% (102/127) of HGF high-expression in stromal cells were significantly associated with increased microvessels density, advanced clinical stage, lymph node metastasis and high-expression of IL-8. Angiogenesis exhibited in relation to overall survival of NPC patients (P=0.001), and the patients with HGF and IL-8 dual high-expression tumors had a significantly worse prognosis than those with single protein high-expression and dual low expression tumors (P=0.011 and P=0.026, respectively). Exogenous HGF was observed to promote induction of IL-8 in NPC cells without EBV infection. Co-operating with IL-8, HGF might contribute to a poor prognosis of NPC by inducing angiogenesis through both autocrine and paracrine EBV-independent pathways.

Expression of protease-activated receptor-2 (PAR-2) in patients with nasopharyngeal carcinoma: correlation with clinicopathological features and prognosis.

We aimed at determining whether the expression of protease-activated receptor 2 (PAR-2) is involved in the progression of nasopharyngeal carcinoma (NPC) and correlated with latent membrane protein 1 (LMP-1), matrix metalloproteinases-9 (MMP9), and angiogenesis of tumor. PAR-2, LMP-1, and MMP9 expressions were detected in 57 biopsies of primary NPC by immunohistochemistry. The presence of Epstein-Barr virus (EBV) was determined using EBER in situ hybridization, and intratumoral microvessels were highlighted by staining endothelial cells for anti-CD34. The correlations with immunostainings and clinicopathological factors, as well as the follow-up data of patients, were analyzed statistically. Strong expression of PAR-2 in 61.4% (35/57) of the biopsies was correlated with extensive lymph node metastasis and advanced stage of NPC. The patients with PAR-2/LMP-1 or PAR-2/MMP9 dual high-expression tumors had a significant worse prognosis than those with single protein high expression and dual low or negative expression tumors (P=0.013 and 0.004, respectively). Angiogenesis in the tumor is related to overall survival of NPC patients (P=0.001), and exhibits strong PAR-2 expression or LMP-1 expression in tumors associated with increased intratumoral microvessel density (P=0.026 and 0.006, respectively). PAR-2 is a possible mediator cooperating with LMP-1 and MMP9 to influence the progression of NPC by inducing angiogenesis and promoting lymph node metastasis.

Effects of aspirin on the development of Helicobacter pylori-induced gastric inflammation and heterotopic proliferative glands in Mongolian gerbils.

BACKGROUND: Helicobacter pylori infection is a major cause of gastritis and gastric carcinoma. Aspirin has anti-inflammatory and antineoplastic activity. The aim of the present study was to determine the effects of aspirin on H. pylori-induced gastritis and the development of heterotopic proliferative glands. METHODS: H. pylori strain SS1 was inoculated into the stomachs of Mongolian gerbils. Two weeks after inoculation, the animals were fed with the powder diets containing 0 p.p.m. (n = 10), 150 p.p.m. (n = 10), or 500 p.p.m. (n = 10) aspirin. Mongolian gerbils were killed after 36 weeks of infection. Uninfected Mongolian gerbils (n = 10) were used as controls. Histologic changes, epithelial cell proliferation and apoptosis, and prostaglandin E(2) (PGE(2)) levels of gastric tissue were determined. RESULTS: H. pylori infection induced gastric inflammation. Administration of aspirin did not change H. pylori-induced gastritis, but alleviated H. pylori-induced hyperplasia and the development of heterotopic proliferative glands. Administration of aspirin accelerated H. pylori-associated apoptosis but decreased H. pylori-associated cell proliferation. In addition, the increased gastric PGE(2) levels due to H. pylori infection were suppressed by treatment with aspirin, especially at the dose of 500 p.p.m. CONCLUSIONS: Aspirin alleviates H. pylori-induced hyperplasia and the development of heterotopic proliferative glands. Moreover, aspirin increases H. pylori-induced apoptosis. We demonstrated the antineoplastic activities of aspirin in H. pylori-related gastric carcinogenesis.

Energy metabolism and survival of liver grafts from non-heart-beating donor rats with warm ischemia injury.

BACKGROUND: The shortage of donor livers is a critical limiting factor for the use of liver transplantation in treatment of end-stage liver diseases. Organs from non-heart-beating donors seem to be an effective option to alleviate this problem. Warm ischemia injury, however, directly influences the grafts' activity and functional recovery after operation. We investigated the energy metabolism and post-transplant survival of liver grafts after different warm ischemia times (WITs) in rats and determined the maximum limit for liver grafts with warm ischemia. METHODS: Rats were randomized into 7 groups with WITs of 0 (control), 10, 15, 20, 30, 45 or 60 minutes. The indices of energy metabolism were measured by reversed-phase high performance liquid chromatograpy and all liver graft specimens were subjected to ultrastructural observation. After orthotopic liver transplantation (OLT), the recovery of energy metabolism in liver grafts after 24 and 48 hours and the survival of the rats were assessed. RESULTS: The levels of adenosine triphosphate (ATP) and energy charge (EC) decreased gradually after different WITs in a time-dependent manner, and this was especially significant within 30 minutes. The levels of ATP and EC in liver grafts with 30 minutes of warm ischemia largely recovered 24 hours after OLT, with 45 minutes of warm ischemia partially recovered 48 hours after OLT, and with 60 minutes of warm ischemia, hardly recovered even 48 hours after OLT. The survival time after OLT did not significantly change with up to 30 minutes of WIT, while long-term survival was reduced with 45 and 60 minutes of WIT. CONCLUSIONS: The levels of ATP and EC after OLT may be important criteria for evaluating the quality of a liver graft. The WIT of a liver graft is closely related to the recovery of hepatic energy metabolism and the graft survival.

Effects of cyclooxygenase-1 and -2 gene disruption on Helicobacter pylori-induced gastric inflammation.

BACKGROUND: Cyclooxygenases (COXs) play important roles in inflammation and carcinogenesis. The present study aimed to determine the effects of COX-1 and COX-2 gene disruption on Helicobacter pylori-induced gastric inflammation. METHODS: Wild-type (WT), COX-1 and COX-2 heterozygous (COX-1+/- and COX-2+/-), and homozygous COX-deficient (COX-1-/- and COX-2-/-) mice were inoculated with H. pylori strain TN2 and killed after 24 weeks of infection. Uninfected WT and COX-deficient mice were used as controls. Levels of gastric mucosal inflammation, epithelial cell proliferation and apoptosis, and cytokine expression were determined. RESULTS: COX deficiency facilitated H. pylori-induced gastritis. In the presence of H. pylori infection, apoptosis was increased in both WT and COX-deficient mice, whereas cell proliferation was increased in WT and COX-1-deficient, but not in COX-2-deficient, mice. Tumor necrosis factor (TNF)-alpha and interleukin-10 mRNA expression was elevated in H. pylori-infected mice, but only TNF-alpha mRNA expression was further increased by COX deficiency. Prostaglandin E2 levels were increased in infected WT and COX-2-deficient mice but were at very low levels in infected COX-1-deficient mice. Leukotriene (LT) B4 and LTC4 levels were increased to a similar extent in infected WT and COX-deficient mice. CONCLUSIONS: COX deficiency enhances H. pylori-induced gastritis, probably via TNF-alpha expression. COX-2, but not COX-1, deficiency suppresses H. pylori-induced cell proliferation.

Epstein-Barr virus infection in precursor lesions of nasopharyngeal carcinoma.

BACKGROUND & OBJECTIVE: The infiltrating neoplastic cells within early-stage nasopharyngeal carcinoma (NPC) are consistently infected with Epstein-Barr virus (EBV). The precursor lesions could often be found in paracancerous epithelium of early-stage NPC. This study was to investigate the role of EBV infection and the intrahost evolution of EBV genotype developed in nasopharyngeal carcinogenesis through detection of EBV harboring in precursor lesions. METHODS: EBV-encoded RNA (EBER) in 15 cases of early-stage NPC biopsy tissue was detected by nucleic acid in situ hybridization. EBV type and latent membrane protein 1 (LMP1) EBV strain in precursor lesions and carcinoma nests were detected by nested polymerase chain reaction (PCR). DNA sequencing of the representative PCR products of carboxyl-terminus of LMP1 gene was analyzed by using four-colored fluorescence terminator sequencing technique. RESULTS: Most infiltrating carcinoma cells of all 15 cases of NPC showed EBER-positive. EBER-positive abnormal epithelial cells and/or infiltrating lymphocytes were found in 14 of 15 cases of precursor lesion. Single A-type EBV was detected in 9 of 11 available DNA samples of carcinoma nest and 9 of 10 available DNA samples of precursor lesion. The carboxyl-terminus of EBV LMP1 gene was detected in all 15 DNA samples of carcinoma nest, among which 14 were single 30-bp deleted LMP1 (del-LMP1) EBV infection and 1 was coinfection of wild-type LMP1 (wt-LMP1) EBV strain and del-LMP1 EBV strain. Among the 11 available DNA samples of precursor lesion suitable for carboxyl-terminus amplification, 5 were coinfection of wt-LMP1 and del-LMP1 EBV, 4 were single del-LMP1 EBV infection, 1 was single wt-LMP1 EBV infection, and 1 showed negative reaction. The DNA sequence of the carboxyl-terminus of wt-LMP1 gene was identical with that of B95-8 cells, while that of del-LMP1 gene had a 30-bp deletion (codon: 346-355) and 4 missense point mutations (codon: 334, 335, 338, and 366). CONCLUSION: EBV infection in nasopharyngeal epithelial cells is a preinvasive event of carcinogenesis of NPC, and the intrahost evolution of EBV genotype would take place during nasopharyngeal carcinogenesis.

[The effect of high dose fluoride on the rat offspring osteoblasts which ingested by female rats].

OBJECTIVE: To investigate the effect of high dose fluoride which ingested by female rats on morphologic change in rat offspring's bone and osteoblast, discuss the relation between the mechanism of fluorosis and cell cycle, cell apoptosis. METHODS: In stock diets condition, Wistar female rats drank distilled water containing 0,50,100,150 mg/L NaF for 2 months, then they are mated with normal rats. The calvarium and osteoblast of offsprings were used to investigate the effects of fluoride on ultrastructure by LM and TEM. FCM was used to analysis cell cycle and apoptosis. RESULTS: The Electron microscope revealed the number of microvilli of osteoblasts were overall decreased in rat offsprings with fluorosis. There was mitochondrial swelling and dilation of the rough endoplasmic reticulum (RER). The matrix of calvarium was hyperplasia and collagen was accumulated and turbulenced. The nuclear manifested the apoptosis character. NaF at 150 mg/ L increased the osteoblast number of S phase with relative decrease of cell number of G2/M phase, but did not change that in G0/G1 phase. The apoptosis percentage increased in this group. CONCLUSION: Excessive fluoride can directly through the placental barrier, influence cell structure and cell cycle distribution of fluorosis rat offspring and render the cell cycle stagnant in S phase, induce apoptosis.

[Study of sequence variations of Epstein-Barr virus LMP1 gene in nasopharyngeal carcinoma].

OBJECTIVE: To detect the sequence variations frequently found within the N- and C-terminal regions of Epstein-Barr virus (EBV) LMP1 gene in nasopharyngeal carcinoma (NPC) and to study the underlying mechanisms. METHODS: Fresh tumor tissues were sampled from 63 patients with untreated NPC encountered in Affiliated Tumor Hospital of Sun Yat-sen University, Guangzhou. The N-terminal region of EBV LMP1 gene was amplified with nested polymerase chain reaction (PCR), followed by XhoI enzyme digestion. Nested PCR was also employed to detect the 30 base pairs deletion within the C-terminal region. Four-colored fluorescence terminator sequencing method was applied for bi-directional solid-phase sequencing of the 8 representative PCR products in 4 cases of NPC. The DNA sequence within the N- and C-terminal regions of LMP1 gene was then analyzed. RESULTS: There were 4 patterns of sequence variations, namely, wt-XhoI/wt-LMP1 (4 cases, 6.3%), wt-XhoI and XhoI-loss/del-LMP1 (4 cases, 6.3%), wt-XhoI/del-LMP1 (5 cases, 7.9%) and XhoI-loss/del-LMP1 (50 cases, 79.5%), detected in the 63 studied cases. Sequence analysis showed that the EBV LMP1 gene had underwent non-synonymous and synonymous substitutions, as compared with the prototype of B95-8 cells. The ratio of non-synonymous to synonymous substitutions was 2.25. CONCLUSIONS: XhoI-loss/del-LMP1 is the predominant sequence variation pattern of EBV LMP1 gene in NPC from Guangzhou. The XhoI-loss variation seems to develop on top of del-LMP1. When compared with the EBV LMP1 gene in peripheral blood B-lymphocytes of virus carriers and in preinvasive epithelial lesions (reported previously), it is likely that the sequence variation patterns of LMP1 gene may represent 4 different phases of intrahost evolution of EBV during nasopharyngeal carcinogenesis.

[Value of EBNA1-IgA and EA-IgG in serological diagnosis of nasopharyngeal carcinoma].

OBJECTIVE: To evaluate the value of EBNA1-IgA and EA-IgG in serological diagnosis of nasopharyngeal carcinoma (NPC). METHODS: The serum EBNA1-IgA and EA-IgG of 56 patients with NPC and 58 healthy adults were detected by ELISA. The sensitivity, specificity, positive predictive value, accuracy rate and odds ratio of the two tests used singly or in combination were compared with each other. RESULTS: The sensitivity of EBNA1-IgA (91.07%) was higher than that of EA-IgG (87.50%), while the specificity of EA-IgG (87.93%) was higher than that of EBNA1-IgA (84.48%). The combination of EBNA1-IgA and EA-IgG could enhance the specificity (94.83%), positive predictive value (0.9375), likelihood ratio (15.5435) and odds ratio (75.0000) for serological diagnosis of NPC. Forty-five patients showed both positive EBNA1-IgA and positive EA-IgG. A positive EA-IgG was detected in 4 out of 5 patients with negative EBNA1-IgA and a positive EBNA1-IgA was founded in 6 out of 7 patients with negative EA-IgG. CONCLUSION: Although relatively high sensitivity and specificity could be obtained by either EBNA1-IgA or EA-IgG test alone, the combination of these two tests with a complementary effect is able to enhance the reliability of serological diagnosis of NPC as most patients have positive ENBA1-IgA and EA-IgG concurrently.

Association of E-cadherin and beta-catenin with metastasis in nasopharyngeal carcinoma.

BACKGROUND: This study was designed to detect methylation of E-cadherin gene promoter and gene mutation of beta-catenin in exon 3 and their expression of protein and mRNA in primary tumor and lymph node metastatic tumor of nasopharyngeal carcinoma (NPC), and investigate the mechanism of invasion and metastasis of neoplastic cells in NPC. METHODS: Fourty-two fresh biopsy samples were taken from untreated NPC patients at the Affiliated Hospital of Sun Yat-sen Medical College, Sun Yat-sen University, Guangzhou, China during the period of 1999-2002. Among them 21 were taken from primary tumors and the other 21 from lymph node metastatic tumors. The gene promoter methylation of E-cadherin was detected by methylation-specific PCR (MSP). The mutation in exon 3 of beta-catenin was detected by direct sequencing analysis. RT-PCR, Western blot and immunohistochemical staining were used to detect the mRNA and protein expression patterns in both primary and metastatic tumors of NPC. RESULTS: Down-regulated expression of E-cadherin in metastatic tumor was compared with that in primary tumor. Reduced expression of E-cadherin was found to be correlated with lymph node metastatic tumor of NPC (P = 0.004); but there was no obvious correlation between primary and metastatic tumors in the expression of beta-catenin (P = 0.698). The mRNA expression level of E-cadherin in metastatic tumors decreased significantly compared with that in primary tumors. However, little change was observed in the mRNA level of beta-catenin in different tumor tissues. Only 4 samples (19.1%) displayed gene promoter methylation of E-cadherin in primary tumor and 10 samples (47.6%) showed methylated form of E-cadherin. The gene promoter methylation of E-cadherin was more common in metastatic tumor than in primary tumor of NPC (P = 0.024). Only 2 (4.76%) of the 42 samples showed mutations in exon 3 of beta-catenin at 41 (T41A, ACC-->GCC) and codon 47 (S47T, AGT-->ACT). The cytoplasmic and nuclear expression of beta-catenin in tumor was not found in any samples of NPC. CONCLUSIONS: The results suggest that the downregulation of E-cadherin results from the gene promoter aberrant methylation of E-cadherin and that the methylation of E-cadherin plays an important role in invasion and metastasis of tumor cells in NPC. However, beta-catenin mutation is an infrequent event in NPC, and beta-catenin is not a critical factor influencing the invasion and metastasis of tumor cells in NPC.