Microstructure and corrosion behavior of porous coatings on titanium alloy by vacuum-brazed method

The microstructural evolution and electrochemical characteristics of brazed porous-coated Ti-6Al-4V alloy were analyzed and compared with respect to the conventionally 1300 degrees C sintering method. The titanium filler metal of low-melting-point (934 degrees C) Ti-15Cu-15Ni was used to braze commercially pure (CP) titanium beads onto the substrate of Ti-6Al-4V alloy at 970 degrees C for 2 and 8 h. Optical microscopy, scanning and transmission electron microscopy, and X-ray diffractometry (XRD) were used to characterize the microstructure and phase of the brazed metal; also, the potentiostat was used for corrosion study. Experimental results indicate that the bead/substrate contact interface of the 970 degrees C brazed specimens show larger contact area and higher radius curvature in comparison with 1300 degrees C sintering method. The microstructure of brazed specimens shows the Widmanst?tten structure in the brazed zone and equiaxed alpha plus intergranular beta in the Ti-6Al-4V substrate. The intermetallic Ti2Ni phase existing in the prior filler metal diminishes, while the Ti2Cu phase can be identified for the substrate at 970 for 2 h, but the latter phase decrease with time. In Hank's solution at 37 degrees C, the corrosion rates of the 1300 degrees C sintering and the 970 degrees C brazed samples are similar at corrosion potential (E(corr)) in potentiodynamic test, and the value of E(corr) for the brazed sample is noble to the sintering samples. The current densities of the brazed specimens do not exceed 100 microA/cm2 at 3.5 V (SCE). These results suggest that the vacuum-brazed method exhibits the potentiality to manufacture the porous-coated specimens for biomedical application.     

Multistate and multifactorial progression of gastric cancer: results from community-based mass screening for gastric cancer

Although multistate progression models for gastric cancer have been proposed, estimation of quantitative parameters of such models is yet to be done. The present study was conducted to elucidate risk factors for gastric cancer and its precursors, and to model the progression rates from superficial gastritis to gastric cancer. Data were derived from a community-based screening programme for gastric cancer in the Matzu region of Taiwan. A total of 2184 residents participated in a two-stage screening project. Subjects testing positive for Helicobacter pylori infection or pepsinogen (PGI or PII/PGII ratio) and immunoglobulin G (IgG), and subjects with a history of peptic ulcer or other upper gastrointestinal disease or with a family history of gastric cancer were referred to endoscopy. We identified 325 biopsy-proven precursors and gastric cancers, including 148 superficial gastritis (SG), 42 atrophic gastritis (AG), 117 intestinal metaplasia (IM) and two gastric cancers. Three further cancers were diagnosed on endoscopy alone and 14 were later diagnosed in those who did not comply with referral to endoscopy. A Markov process model was used to estimate the progression rates from superficial gastritis through to gastric cancer, with exponential regression to assess the effect of covariates on progression rates. The annual progression rate from SG to AG was 0.0670 (95% confidence interval [CI] 0.0446-0.0895). Annual progression rates from AG to IM and from IM to gastric cancer were 0.2775 (0.1665-0.3884) and 0.2265 (0.1315-0.3214), respectively. This gives average dwelling times in AG and IM of 3.60 years and 4.42 years, respectively. Progression from no disease to SG was significantly accelerated in those testing positive for H. pylori, those testing positive for PGI and in subjects with a family history of gastric cancer or a personal history of upper gastrointestinal disease. Further progression to AG and IM was significantly accelerated in those testing positive for PGI and in those with a history of upper gastrointestinal disease.     

Detection of Epstein-Barr virus infection and gene expression in human tumors by microarray analysis

Epstein-Barr virus (EBV) genome-chips are employed to determine the EBV infection rate and to reveal the gene expression patterns of EBV in tumor biopsies. These chips are produced with 71 consecutive PCR-amplified EBV DNA fragments of 1-3 kbp covering the entire EBV genome. The specificity of the EBV-chips is determined by hybridizing the DNA on the chips with biotin-labeled cDNA probes reverse transcribed from the mRNA of P3HR1 cells, which were B-cell infected latently by EBV. Hybridization results revealed only the expression of EBNA1, EBNA2, EBER1 and EBER2 in these cells. On the other hand, EBV lytic genes are expressed after the cells are treated with 12-O-tetradecanoylphorbol-13-acetate and sodium butyrate to induce the EBV lytic cycle. Fourty-four tumor biopsies from different organs are assayed with these chips, which showed many defined and interesting EBV gene expression patterns. This study demonstrates that the EBV-chip is useful for screening infection with EBV in tumors, which may lead to insights into tumorigenesis associated with this virus.     

Natural resistance-associated macrophage protein 1 gene polymorphisms in rheumatoid arthritis

OBJECTIVES: To investigate the association of natural resistance-associated macrophage protein 1 gene (NRAMP1) polymorphisms with rheumatoid arthritis (RA) in Taiwan. METHODS: NRAMP1 polymorphisms were determined from 113 RA patients and 74 healthy controls using the polymerase chain reaction/restriction fragment length polymorphism method. RESULTS: The genotype frequencies of NRAMP1 823 C/C, 1703G/G (543D/D), and 1729+55 del 4 TGTG+/+ (244/244) were significantly higher in patients with RA than in controls. Similar findings were also evident in allele frequencies and allele carriage frequencies of 823C, 1703G (543D), and 1729+55 del 4 TGTG+ (244). The associations of these polymorphisms with RA were independent of HLA-DR4. Linkage disequilibria could be found between 823C and 1703G, and between 1703G and 1729+55 del 4 TGTG+. The estimated haplotype frequency of NRAMP1 823C/1703G/1729+55 del 4 TGTG+ was significantly increased in RA patients compared with controls. We also found that patients with 823 C/C had a significantly lower prevalence of rheumatoid nodule than those without 823 C/C. CONCLUSION: NRAMP1 823C, 1703G (543D), and 1729+55 del 4 TGTG+ (244) are precipitating factors for the development of RA in Taiwan. The estimated NRAMP1 823C/1703G/1729+del 4 TGTG+ haplotype is associated with susceptibility to RA. NRAMP1 823 C/C prevents the development of rheumatoid nodule in RA patients.     

Expression of Rsf-1, a chromatin-remodeling gene, in ovarian and breast carcinoma

Rsf-1 protein is a member of a chromatin-remodeling complex that plays an important role in regulating gene expression and cell proliferation. Our previous study showed that Rsf-1 was an amplified gene that participated in the development of ovarian serous carcinoma. To further elucidate the role of Rsf-1 in ovarian cancer, we studied Rsf-1 immunoreactivity in 294 ovarian tumors of various histologic types. Because the Rsf-1 amplicon overlaps an amplified region reported in breast cancer, we included 782 neoplastic and normal breast tissues for comparison. Immunohistochemistry was performed on tissue microarrays using a 4-tiered scoring system. Overexpression of Rsf-1 was defined as a nuclear immunointensity of 3+ to 4+ because of a strong correlation between 3+ and 4+ immunointensity and Rsf-1 gene amplification, based on our previous fluorescence in situ hybridization analysis. Rsf-1 overexpression was observed in 25% of high-grade ovarian serous carcinomas and in only rare cases (<7%) of low-grade ovarian serous, ovarian endometrioid, and invasive breast carcinomas but not in any ovarian serous borderline tumors, ovarian clear cell carcinomas, ovarian mucinous carcinomas, intraductal carcinomas of the breast, and normal ovaries and breast tissues. Thus, overexpression of Rsf-1 was significantly associated with high-grade ovarian serous carcinoma (P < .05), as compared with other types of ovarian tumors and breast carcinomas. Our results provide evidence that Rsf-1 expression is primarily confined to high-grade serous carcinoma, the most aggressive ovarian cancer. Because Rsf-1 overexpression occurs in only a small number of breast carcinomas, it is unlikely that Rsf-1 is a critical gene in the development of breast carcinoma.     

Porous acellular bovine pericardia seeded with mesenchymal stem cells as a patch to repair a myocardial defect in a syngeneic rat model

A patch is often mandatory to repair myocardial defects; however, currently available patches lack the possibility of regeneration. To overcome this limitation, a porous acellular bovine pericardium seeded with BrdU-labeled mesenchymal stem cells (MSCs) was prepared (the MSC patch) to repair a surgically created myocardial defect in the right ventricle of a syngeneic rat model. The bovine pericardium before cell extraction was used as a control (the Control patch). The implanted samples were retrieved at 4- and 12-week postoperatively (n=5 per group at each time point). At retrieval, no aneurysmal dilation of the implanted patches was seen for both studied groups. No apparent tissue adhesion was observed for the MSC patch throughout the entire course of the study, while for the Control patch, two out of the five studied animals at 12-week postoperatively had a filmy adhesion to the chest wall. On the inner (endocardial) surface, intimal thickening was observed for both studied groups; however, no thrombus formation was found. Intact layers of endothelial and mesothelial cells were identified on the inner and outer (epicardial) surfaces of the MSC patch. Smooth muscle cells together with neo-muscle fibers, neo-glycosaminoglycans and neo-capillaries were observed within the pores of the MSC patch. Some cardiomyocytes, which stained positively for BrdU and alpha-sacromeric actin, were observed in the MSC patch, indicating that the implanted MSCs can engraft and differentiate into cardiomyocytes. Additionally, a normality of the local electrograms on the epicardial surface of the MSC patch was observed. In contrast, no apparent tissue regeneration was observed for the Control patch throughout the entire course of the study, while only abnormal electrogram signals were seen on its epicardial surface. In conclusion, the MSC patch may preserve the structure of the ventricular wall while providing the potential for myocardial tissue regeneration.     

Descriptive and longitudinal observations on the relationship of borderline personality disorder and bipolar disorder

OBJECTIVE: The purpose of this study was to test whether borderline personality disorder is a variant of bipolar disorder by examining the rates of co-occurrence in both disorders, the effects of co-occurrence on a longitudinal course, and whether the presence of either disorder confers the risk for new onsets of the other. METHOD: A prospective repeated-measures design with reliable independent diagnostic measures and 4 years of follow-up was used to assess 196 patients with borderline personality disorder and 433 patients with other personality disorders. RESULTS: Patients with borderline personality disorder had a significantly higher co-occurrence of bipolar disorder (19.4%) than did patients with other personality disorders. However, this co-occurrence did not appear to affect the subsequent course of borderline personality disorder. Although only 8.2% of the borderline personality disorder patients developed new onsets of bipolar disorder, this rate was higher than in patients with other personality disorders. Patients with other personality disorders with co-occurring bipolar disorder generally had more new onsets of borderline personality disorder (25%) than did patients with other personality disorders without co-occurring bipolar disorder (10%). CONCLUSIONS: A modest association between borderline personality disorder and bipolar disorder is reported.     

Comorbid psychiatric disorders, sex, and methamphetamine use in adolescents: a case-control study

The purpose of this case-control study was to elucidate the relative proportions of amphetamine use disorder (AUD) and amphetamine-induced disorder (AID) in a group of adolescents with the use of methamphetamine (MAMP) and to examine the risks for psychiatric comorbidity and sex for MAMP use. Psychiatric comorbidity in the preceding year was determined for 200 adolescent MAMP users and 400 drug-free control subjects by diagnostic interview using the Kiddie epidemiologic version of the Schedule for Affective Disorders and Schizophrenia. The proportions of AUD and AID were calculated, and the association between psychiatric comorbidity, sex, and MAMP use was assessed. The results revealed that among the MAMP users, 65 subjects (32.5%) had AUD, whereas 19 (9.5%) had AID. Early use of MAMP use was seen in AUD, whereas high-frequency MAMP use was associated with the occurrence of AID. Alcohol, nicotine, and betel nut use disorders were more prevalent in MAMP users for both sexes. By applying conditional logistic regression analysis, it was demonstrated that MAMP use was associated with conduct disorder in males, whereas in females, it was associated with conduct disorder and adjustment disorder. The results indicated that age of first use and subsequent frequency of MAMP use appeared to be associated with the development of amphetamine-related disorders. Sex differences in the association between psychiatric comorbidity and MAMP use were demonstrated. These factors have to be taken into consideration when intervening for adolescent MAMP use.