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.

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.

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.

[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.

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.

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.

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.

[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.

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.

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.

Macrophage migration inhibitory factor enhances neoplastic cell invasion by inducing the expression of matrix metalloproteinase 9 and interleukin-8 in nasopharyngeal carcinoma cell lines.

BACKGROUND: Nasopharyngeal carcinoma (NPC) shows highly invasive and metastatic features. This study aims to investigate macrophage migration inhibitory factor (MIF)-induced invasion of NPC cells in vitro and the effects on matrix metalloproteinases (MMPs) and interleukin-8 (IL-8), and to study the mechanism of tumor cell invasion and metastasis in the early stage of NPC. METHODS: Two nasopharyngeal carcinoma cell lines, CNE-1 and CNE-2, were adopted in this study. The NPC cell invasion and migration were evaluated by microinvasion assay. The variation of expression percentages of MMP2- or MMP9-positive cells was detected by flow cytometry in two cell lines with or without MIF treatment. Western blotting and RT-PCR were used to assay the protein and mRNA expressions of MMP2 and MMP9. The IL-8 concentration secreted by NPC cells was compared with the cells with different treatments using ELISA. RESULTS: After treating with MIF for 48 hours, the cell numbers of CNE-1 and CNE-2 which went through the 8-microm filter membrane were increased. Compared with non-MIF treated NPC cells, significant difference could be found both in CNE-1 (P = 0.005) and CNE-2 cells (P = 0.001). The percentages of MMP9-positive cells were significantly increased in both CNE-1 [from (28.5 +/- 2.5)% to (82.4 +/- 3.5)%, P = 0.001] and CNE-2 [from (32.8 +/- 3.5)% to (86.1 +/- 1.6)%, P = 0.002]. The relative intensity of MMP9 protein expression was also enhanced in both cell lines (CNE-1: from 83.1 +/- 6.0 to 242.9 +/- 22.9, P = 0.002; CNE-2: from 84.4 +/- 4.3 to 278.9 +/- 29.7, P = 0.003). Correspondingly, the increased MMP9 mRNA expression level was significantly detectable in both cell lines. The concentration of IL-8 in the supernatant of CNE-2 was higher [(1201.8 +/- 593.3) pg/ml] after treatment. It was also remarkably higher than that in the supernatant of CNE-2 without treatment (P = 0.026). However, there was no significant difference in the concentration variation of IL-8 in CNE-1 (P = 0.581), while the IL-8 mRNA level was only enhanced in CNE-2. CONCLUSIONS: MIF can induce potent invasion of NPC cell lines in vitro, and the infiltrating lymphocytes in NPC might be responsible for the invasion and metastasis of tumor cells. MIF cytokine which is secreted by these infiltrating lymphocytes might contribute to the invasion as well as metastasis of NPC in the early stages by induction of MMP9 and IL-8 in an indirect pathway.

Dynamic microcirculatory changes in liver graft from non-heart-beating donor with warm ischemia injury in rat.

BACKGROUND: Since the 1990s, liver grafts from non-heart-beating donor (NHBD) have become an alternative because of the deficiency of grafts from heart-beating-donors (HBDs). Warm ischemia injury, however, directly influences the grafts' activity and functional recovery after operation. We investigated the microcirculatory change of liver graft at different warm ischemia time (WIT) in rats and determined the maximum limitation of liver graft to warm ischemia. METHODS: According to WIT, 120 rats were divided randomly into 5 groups of 0, 15, 30, 45, 60 minutes respectively. The microcirculatory changes of their liver grafts were measured including serum level of hyaluronic acid (HA) and ultrastructural changes. After orthotopic liver transplantation (OLT), the recovery of microcirculation of the liver grafts after 24 hours, 48 hours and 3 days was observed. RESULTS: Microcirculatory changes and function of the liver grafts became normal after reperfusion when the WIT was less than 30 minutes. In the 45-minute WI group, part of blood sinusoids was full of cytoplasmic blebs stemming from the microvilli of hepatocytes and hemocytes. The serum level of HA in each group after 45 minutes of WI recovered after reperfusion. CONCLUSIONS: The microcirculatory change of rat liver graft is reversible when the WIT is less than 30 minutes: rat liver graft could be safely subject to warm ischemia within 30 minutes. The maximal 45 minutes of WI can be tolerated by the microcirculatory function of liver graft. After 60 minutes of WI, irreversible disturbance of microcirculation may appear.

[Influence of E-cadherin promoter methylation and mutation of beta-catenin on invasion and metastasis of nasopharyngeal carcinoma cells].

OBJECTIVE: To study the mechanism of invasion and metastasis in early nasopharyngeal carcinoma (NPC) in relation to E-cadherin promoter methylation and mutation in exon 3 of beta-catenin. METHODS: Methylation of E-cadherin promoter, mutation in exon 3 of beta-catenin and differential expression of beta-catenin in the primary lesion of 21 NPC and the metastatic lymph node of 21 NPC were investigated by DNA Methylation-Specific PCR, direct sequencing and immunohistochemical method. RESULTS: Methylation on E-cadherin promoter was showed in 23.8% (5/21) primary lesions and 61.9% (13/21) metastatic lymph nodes (P < 0.01). Mutation in exon 3 of beta-catenin was showed in 3 of 42 tissues: codon 37 (TCT-->GCT), codon 41 (ACC-->GCC) and codon 47 (AGT-->ACT). However, there was no relation between these mutations and invasion or metastasis (P > 0.05). High beta-catenin expression on the membrane without nuclear expression was observed in 42 tissues (P > 0.05). CONCLUSION: 1. In NPC, methylation of promoter is a major cause of down-regulation of E-cadherin which may finally lead to detachment and metastasis of neoplastic cells, 2. Mutation in exon 3 of beta-catenin is a rare event in NPC. It may be an early event in the carcinogenesis of NPC but have no significant role in invasion and metastasis and 3. High expression of beta-catenin, as one of NPC characteristics, is not a key factor for invasion or metastasis.

[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.

[The influence of warm ischemia injury on viability and posttransplantative outcome of liver graft from non-heart-beating donor in rats].

OBJECTIVE: To investigate the dynamical changes of histology, histochemistry, energy metabolism, liver function and posttransplantive survival of liver graft under different warm ischemia times (WIT) in rats and determine the maximum limitation of liver graft to warm ischemia. METHODS: According to WIT, the rats were randomized into 7 groups, WIT were 0, 10, 15, 20, 30, 45, 60 minutes respectively. The recovery changes of above-mentioned index were observed or measured after liver transplantation. The graft survival and postoperative complications in each subgroup were analyzed. RESULTS: Liver graft injury was reversible and gradually resumed normal structure and function after reperfusion when WIT was less than 30 minutes. In terms of graft survival, there was no significant difference between subgroups within 30 WIT. When WIT was prolonged to 45 minutes, the recipients long-term survival was severely insulted, and both function and histological structure of liver graft would develop irreversible damage when WIT was prolonged to 60 minutes. CONCLUSION: These results indicate that rat liver graft could be safely subject to warm ischemia within 30 minutes. The levels of adentriphos (ATP) and energy charge (EC) and the activities of glycogen and enzyme-histochemistry of liver graft and its recovery potency after reperfusion may serve as the important criteria to evaluate the quality of liver graft.

[Increased cell migration of nasopharyngeal carcinoma cell lines in vitro by macrophage migration inhibitory factor].

OBJECTIVE: To study whether macrophage migration inhibitory factor (MIF) can increase the ability of invasion of nasopharyngeal carcinoma cell lines in vitro, and to investigate the mechanism of invasion and metastasis of tumor cells during the early stage of nasopharyngeal carcinoma (NPC). METHODS: The invasion and migration of NPC cell lines, CNE-1 and CNE-2, were evaluated by micron-migration assay in a chamber with 8- micro m porosity polycarbonate filter membrane. Flow cytometry and western blotting were adopted respectively to evaluate the protein expression level of matrix metalloproteinase 2 and 9 (MMP2, MMP9) in MIF treated or non-treated tumor cell lines. The concentrations of interleukin 8 (IL-8) secreted into the culture supernatant by the cells were measured by using Enzyme-linked immunoabsorbent assay (ELISA). RESULTS: (1) After treatment with MIF for 24 hours, the number of cells passing through the 8- micro m filter membrane were increased in CNE-1 (113.7 +/- 20.9) and CNE-2 (311.3 +/- 48.9), as compared with that of non-MIF treated NPC cells. A significant statistic difference (P = 0.005, P = 0.001) was obtained in both CNE-1 and CNE-2 cells. (2) After treatment with MIF, the number of MMP9-positive cells increased in both CNE-1 (from 28.5% +/- 2.45% to 82.4% +/- 3.49%, P = 0.001) and CNE-2 (from 32.8% +/- 3.48% to 86.1% +/- 1.62%, P = 0.002) cell lines. In addition, an enhanced MMP9 protein expression up to 3-fold was observed in both cell lines. However, the expression level of MMP2 did not changed significantly between treated and non-treated cell lines (P > 0.05). (3) The concentration of IL-8 in the culture supernatant of CNE-2 was 1201.8 +/- 593.3 pg/ml after treatment with MIF for 24 h, remarkably higher than that without MIF treatment (32.7 +/- 20.1 pg/ml, P = 0.026). A similar change was not detected in CNE-1 (P = 0.581) cells. CONCLUSIONS: (1) MIF can increase cell migration of CNE-1 and CNE-2 NPC cell lines in vitro. (2) A higher expression level of MMP9 and an up-regulated IL-8 by MIF may play a very important role in the progress of NPC, such as invasion and metastasis.

[Detection of gene promoter methylation and mRNA, protein expression levels of E-cadherin in nasopharyngeal carcinoma].

OBJECTIVE: To detect the gene promoter methylation, mRNA and protein expression levels of E-cadherin and beta-catenin in primary and metastatic tumor samples of nasopharyngeal carcinoma (NPC), and to investigate the mechanism of invasion and metastasis of neoplastic cell in NPC. METHODS: Twenty-one patients with NPC were studied. The samples of primary tumor and paired lymph node metastatic tumor were collected and examined for aberrant gene promoter methylation in E-cadherin by DNA Methylation-specific polymerase chain reaction (MSP). Reverse transcriptase polymerase chain reaction (RT-PCR), Western blotting and immunohistochemical staining were adopted to detect mRNA and protein levels of E-cadherin and beta-catenin. RESULTS: (1) The gene promoter methylation in E-cadherin was 52.4% (11/21) in primary tumor of NPC, and 80.9% (17/21) in lymph node metastatic tumor, which existed significant difference (P < 0.05). (2) In primary tumor, about 80% (0 approximately 100%) neoplastic cells expressed E-cadherin protein on the average, which was significantly higher than that of metastatic tumor (50% on the average, P = 0.004). The expression levels of beta-catenin protein were high in both primary and metastatic tumors, but with no statistic difference (P = 0.698). (3) By Western blotting analysis, the relative intensity of protein expression in E-cadherin was significantly higher in primary tumor (206.7 +/- 32.7) compared to that of metastatic tumor (65.0 +/- 15.9), while the expression of beta-catenin protein showed no difference between them (P = 0.754). (4) mRNA expression level of E-cadherin was higher in primary tumor than that of metastatic tumor.No remarkable difference was found for the mRNA expression of beta-catenin. CONCLUSIONS: (1) Downregulation of mRNA and protein expression of E-cadherin may play a critical role in neoplastic cell invasion and metastasis in NPC. The aberrant promoter methylation of E-cadherin may ultimately alter the mobility and scattering of tumor cells in NPC. (2) Downregulation of E-cadherin alone may be enough for the tumor cell to lose intercellular adhesions which results in tumor cell invasion and metastasis. However, mutant beta-catenin could also involve in this progress. (3) The detection of gene promoter hypermethylation of E-cadherin should be evaluated in the screening and surveillance of NPC.

[Comparison of the Epstein-Barr virus infection and 30 bp-deleted LMP1 gene among 4 histologic types of nasopharyngeal carcinoma].

OBJECTIVE: To compare the Epstein-Barr virus (EBV) infection rates and the frequencies of wt-LMP1 and del-LMP1 EBV variants detected singly or dually among the four types of nasopharyngeal carcinoma (NPC) and to illustrate the possible role of del-LMP1 gene in nasopharyngeal carcinogenesis. METHODS: EBER in situ hybridization was performed in 117 NPCs, including 48 non-keratinizing carcinomas (NKCs), 25 keratinizing squamous cell carcinomas (KSCCs), 5 adenosquamous carcinomas (ASCs), 6 mucoepidermoid carcinomas (MECs) and 33 adenocarcinomas (ACs). Nested PCR for demonstration of EBV LMP1 gene was performed on the tissue samples collected from 99 EBER-positive carcinoma cases and the peripheral blood mononuclear cells (PBMCs) of 53 healthy adults (HAs). RESULTS: As indicated by EBER in-situ hybridization, the EBV infection rates in both of 48 NKCs and 25 KSCCs were 100%; and the infection rates of 11 ASCs/MECs and 33 ACs were 9/11 and 51.5% (17/33), respectively. Worthy to note was that most of the NKC cells were EBER-positive while only a small number of EBER-positive neoplastic cells could be found in 17 ACs. The percentage of del-LMP1 EBV variant detected singly in NKCs (85.4%, 41/48) was not only significantly higher than that in PBMCs of 46 HAs (8.7%, 4/46) but also significantly higher than those detected in KSCCs (16.0%, 4/25). The dual infection rate of wt-LMP1 and del-LMP1 variants detected in KSCCs (56.0%, 14/25) was significantly higher than that of NKCs (12.5%, 6/48). The majority of the EBV detected in AC tissues (12/17) and HAs' PBMCs (34/46, 73.7%) were of dual wt-LMP1 and del-LMP1 variants. CONCLUSIONS: The EBV infection rates are significantly different among 3 major histological categories, namely, NKC/KSCC, ASC/MEC and AC. Though NKCs and KSCCs are always consistently associated with EBV, the single del-LMP1 EBV variant detected in NKCs is predominant over that in KSCCs and most of the KSCCs contain dual wt-LMP1 and del-LMP1 EBV variants. The EBV of the del-LMP1 variant might play a crucial role in carcinogenesis of NKC.