Associations of plasma aflatoxin B1-albumin adduct level with plasma selenium level and genetic polymorphisms of glutathione S-transferase M1 and T1

Mortality from hepatocellular carcinoma (HCC) is extraordinarily high in Matzu, an island off the coast of Southeastern China. To investigate factors associated with plasma aflatoxin B1 (AFB1)-albumin adduct level, we studied 304 healthy adult residents from Matzu. AFB1-albumin adducts were determined by competitive enzyme-linked immunosorbent assay, hepatitis B surface antigen status by enzyme immunoassay, genotypes of glutathione S-transferase (GST) M1 and T1 by polymerase chain reaction, plasma selenium by atomic absorption spectrometry, and plasma retinol, alpha-tocopherol, alpha-carotene, and beta-carotene levels by high-performance liquid chromatography. Men had higher AFB1-albumin adduct levels than women. GSTM1-nonnull and GSTT1-null genotypes and low plasma selenium level were significantly associated with an increased level of AFB1-albumin adducts among men, whereas age was significantly correlated with adduct level among women. High intake of fermented beans was associated with an increased adduct level among men and women. The inverse associations between plasma selenium level and AFB1-albumin adducts were statistically significant among those with null genotypes of GSTM1 and GSTT1, but not among the nonnull genotypes. This study provides insight into the dietary and genetic factors influencing AFB1-albumin adduct formation in an isolated population with high liver cancer mortality.

Serologic markers of Epstein-Barr virus infection and nasopharyngeal carcinoma in Taiwanese men

BACKGROUND

It is probable but unproven that Epstein-Barr virus (EBV) has a role in nasopharyngeal carcinoma. We determined whether antibodies against EBV are present before the development of nasopharyngeal carcinoma.

METHODS

A total of 9699 men were enrolled between 1984 and 1986. Blood samples were examined for IgA antibodies against EBV capsid antigen and neutralizing antibodies against EBV-specific DNase. During 131,981 person-years of follow-up, 22 pathologically confirmed new cases of nasopharyngeal carcinoma that were diagnosed more than one year after recruitment were ascertained through linkage with the National Cancer Registry of Taiwan.

RESULTS

The cumulative risk of nasopharyngeal carcinoma per 100,000 person-years was 11.2 for subjects who tested positive for neither serologic marker, 45.0 for those who had one marker, and 371.0 for those who had both markers. After adjustment for age and the presence or absence of a family history of nasopharyngeal carcinoma, the relative risk of nasopharyngeal carcinoma was 32.8 for subjects with both markers (95 percent confidence interval, 7.3 to 147.2; P<0.001) and 4.0 for subjects with one marker (95 percent confidence interval, 1.6 to 10.2; P=0.003), as compared with subjects with neither marker. The longer the duration of follow-up, the greater the difference in the cumulative incidence of nasopharyngeal carcinoma between seropositive and seronegative subjects.

CONCLUSIONS

IgA antibodies against EBV capsid antigen and neutralizing antibodies against EBV DNase are predictive of nasopharyngeal carcinoma.

Manganese stimulates stellation of cultured rat cortical astrocytes

We investigated the effect of manganese on the morphology of cultured rat cortical astrocytes. Astrocytes exhibited flattened, polygonal morphology in the absence of stimulation, and differentiated into process-bearing stellate cells following exposure to MnCl(2). MnCl(2)-induced stellation was a reversible process, which depended on the presence of extracellular free manganese. MnCl(2)-induced stellation did not stop with the introduction of pertussis toxin, PD98059, SB203580, phorbol 12-myristat 13-acetate, SQ22536, or LY83583. Alternatively, MnCl(2)-induced stellation did stop when exposed to colchicine and sodium orthovanadate, suggesting the involvement of the cytoskeletal elements and orthovanadate-sensitive protein tyrosine phosphatase. MnCl(2) might function as a factor regulating astrocyte morphology.

Carcinoembryonic antigen cell adhesion molecule 1 directly associates with cytoskeleton proteins actin and tropomyosin

CEA cell adhesion molecule 1 (CEACAM1), a type 1 transmembrane and homotypic cell adhesion protein belonging to the carcinoembryonic antigen (CEA) gene family and expressed on epithelial cells, is alternatively spliced to produce four major isoforms with three or four Ig-like ectodomains and either long (CEACAM1-L) or short (CEACAM1-S) cytoplasmic domains. When murine MC38 (methylcholanthrene-induced adenocarcinoma 38) cells were transfected with human CEACAM1-L and stimulated with sodium pervanadate, actin was found to co-localize with CEACAM1-L at cell-cell boundaries but not in untreated cells. When CEACAM1-L was immunoprecipitated from pervanadate-treated MC38/CEACAM1-L cells and the associated proteins were analyzed by two-dimensional gel analysis and mass spectrometry, actin and tropomyosin, among other proteins, were identified. Whereas a glutathione S-transferase (GST) fusion protein containing the l-isoform (GST-Cyto-L) bound poorly to F-actin in a co-sedimentation assay, the S-isoform fusion protein (GST-Cyto-S) co-sedimented with F-actin, especially when incubated with G-actin during polymerization (K(D) = 7.0 microm). Both GST-Cyto-S and GST-Cyto-L fusion proteins bind G-actin and tropomyosin by surface plasmon resonance studies with binding constants of 0.7 x 10(-8) and 1.0 x 10(-7) m for GST-Cyto-L to G-actin and tropomyosin, respectively, and 3.1 x 10(-8) and 1.3 x 10(-7) m for GST-Cyto-S to G-actin and tropomyosin, respectively. Calmodulin or EDTA inhibited binding of the GST-Cyto-L fusion protein to G-actin, whereas calmodulin and G-actin, but not EDTA, stimulated binding to tropomyosin. A biotinylated 14-amino acid peptide derived from the juxtamembrane portion of the cytoplasmic domain of CEACAM1-L associated with both G-actin and tropomyosin with K(D) values of 1.3 x 10(-5) and 1.8 x 10(-5) m, respectively. These studies demonstrate the direct interaction of CEACAM1 isoforms with G-actin and tropomyosin and the direct interaction of CEACAM1-S with F-actin.

Association between genetic polymorphism of tumor necrosis factor-alpha and risk of oral submucous fibrosis, a pre-cancerous condition of oral cancer

Many cytokines have been thought to play important roles in the pathogenesis of oral submucous fibrosis (OSF), an areca nut chewing-specific pre-cancerous condition characterized by the deposition of collagen in oral submucosa. Tumor necrosis factor-alpha (TNF-alpha), situated in the class III region of human leukocyte antigen (HLA), is a mediator with multiple functions, including the regulation of inflammatory reaction and transcriptions of collagen and collagenase. In total, 809 male subjects were recruited for assessment of the association of OSF with a bi-allelic promoter-region (-308) polymorphism on the TNFA gene. The high production allele, TNF2, was significantly lower among OSF subjects (n = 166) than in areca-chewing controls (n = 284). This association was independent of oral cancer status. The multivariate-adjusted odds ratio for the TNFA 11 genotype was 2.6 (95% confidence interval = 1.4-4.9; p = 0.004). The finding may imply a multifunctional etiological factor of TNF-alpha in OSF pathogenesis.

Intramedullary high signal intensity on T2-weighted MR images in cervical spondylotic myelopathy: prediction of prognosis with type of intensity

PURPOSE

To examine whether the different appearances of intramedullary high signal intensity (SI) on T2-weighted MR images in cervical spondylotic myelopathy are related to differences in surgical prognosis.

MATERIALS AND METHODS

The magnetic resonance (MR) findings and Japanese Orthopedic Association (JOA) score of 64 cervical spondylotic myelopathy patients, who underwent decompression surgery, were evaluated. SIs were classified as type 0 if no intramedullary high SI on T2-weighted MR images was noted, type 1 if a predominantly (>50%) faint and fuzzy border of high SI was noted, or type 2 if a predominantly (>50%) intense and well-defined border of high SI was noted. Postoperative JOA scoring and MR imaging were also performed 6 months after surgery. Recovery ratios were calculated.

RESULTS

There were 20 type 0, 23 type 1, and 21 type 2 cases. Statistical analyses showed no significant difference in age, sex, cervical curvature, and preoperative JOA score between the three groups. Statistical analyses of the recovery ratio showed significantly poor prognosis of type 2 compared with type 1 (P < .001) and type 0 (P =.001), but no difference between types 0 and 1 (P = .317). After controlling for factors of age, sex, preoperative JOA score, cervical curvature, and cord compression ratio, analysis of covariance showed the same result.

CONCLUSION

Type 1 intramedullary high SI on T2-weighted MR images indicates a better surgical outcome than does type 2.

Role of reactive oxygen intermediates in Japanese encephalitis virus infection in murine neuroblastoma cells

Infection with Japanese encephalitis virus (JEV), a mosquito-borne, neurotropic flavivirus, may cause acute encephalitis in humans and induce severe cytopathic effects in various types of cultured cells. This study attempted to determine whether JEV infection induces free radical generation and whether oxidative stress contributes to virus-induced cell death in neuroblastoma cells. A rise in the intracellular level of free radicals indicated by the 2',7'-dichlorofluorescein fluorescence was observed in N18 cells following JEV infection. Cellular flavon-containing enzymes were involved in JEV-induced fluorescent change. Cells were moderately protected from JEV-induced death by diphenyleneiodonium, a flavon-containing enzyme inhibitor, whereas common antioxidants such as N-acetylcysteine, pyrrolidine dithiocarbamate, Tiron, and Trolox turned out to be ineffective. These results suggest that the direct antioxidant action is not helpful in prevention of JEV-induced neuronal cell death.

Tyrosine kinase signaling involved in glutamate-induced astrocyte proliferation

Proliferation of astrocytes is a common response of the CNS to injury and disease. The mechanisms controlling the proliferation of astrocytes are of great interest. In this paper, the signaling pathways underlying glutamate-induced astrocyte proliferation are investigated. Glutamate stimulates the proliferation of non-synchronized, subconfluent cultures of rat cortical astrocytes. Glutamate-induced cell proliferation is not prevented by inhibitors of G protein, protein kinase A, protein kinase C, phosphatidylinositol 3 kinase, extracellular signal-regulated kinase, or phospholipase A2. However, the tyrosine kinase inhibitors Genistein and Herbimycin A inhibit the glutamate-induced proliferation. Moreover, this proliferation is mediated by the activation of glutamate metabotropic receptors. These results suggest that glutamate induces astrocyte proliferation through a tyrosine kinase pathway.

KIT activation is a ubiquitous feature of gastrointestinal stromal tumors

Gastrointestinal stromal tumors (GISTs) are the most common mesenchymal tumors of the gastrointestinal tract, and they are generally resistant to chemotherapy and radiation therapy. Most GISTs express the KIT receptor tyrosine kinase protein, and a subset of GISTs contain activating mutations within the KIT juxtamembrane region. We evaluated 48 GISTs, including 10 benign, 10 borderline, and 28 malignant cases, to determine whether KIT expression and activation are general properties of these tumors. Immunohistochemical KIT expression was demonstrated in each case. Somatic KIT mutations were found in 44 tumors (92%), of which 34 (71%) had juxtamembrane region mutations. Other GISTs had KIT mutations in the extracellular region (n = 6) and in two different regions in the tyrosine kinase domain (n = 4). Contrary to previous reports, KIT mutations were not identified preferentially in higher-grade tumors: indeed, they were found in each of 10 histologically benign GISTs. Notably, mutations in all KIT domains were associated with high-level KIT activation/phosphorylation, and KIT activation was also demonstrated in the four GISTs that lacked detectable KIT genomic and cDNA mutations. These studies underscore the role of KIT activation in GIST pathogenesis, and they suggest that activated KIT might represent a universal therapeutic target in GISTs.

Hormonal markers and hepatitis B virus-related hepatocellular carcinoma risk: a nested case-control study among men

BACKGROUND

The incidence of hepatitis B virus (HBV)-related hepatocellular carcinoma (HCC) is higher in men than in women. We examined whether endogenous sex hormone levels or hormone-related factors might affect the risk of HCC in men.

METHODS

Baseline blood samples were collected from 4841 male Taiwanese HBV carriers without diagnosed HCC from 1988 through 1992. Plasma testosterone and estradiol levels and genetic polymorphisms in the hormone-related factors cytochrome P450c17 alpha (CYP17, A1 versus A2 alleles), steroid 5 alpha-reductase type II (SRD5A2, valine [V] versus leucine [L] alleles), and androgen receptor (AR, number of CAG repeats) were assayed among 119 case patients who were diagnosed with HCC during 12 years of follow-up and 238 control subjects. All statistical tests were two-sided.

RESULTS

The risk of HCC increased with increasing concentrations of testosterone (odds ratio [OR](highest versus lowest tertile) = 2.97; 95% confidence interval [CI] = 1.54 to 5.70; P(trend) <.001) and with increasing number of the V allele of the SRD5A2 V89L polymorphism (OR(VV versus LL genotype) = 2.47; 95% CI = 1.21 to 5.03; P(trend) =.011). Fewer AR gene CAG repeats (<23 repeats) were associated with a 1.64-fold (95% CI = 1.00 to 2.68) increased risk of HCC. Although the CYP17 genotype alone did not increase the risk of HCC, there was evidence of a gene-gene interaction, because the CYP17 A1 allele statistically significantly increased the risk of HCC in the presence of fewer AR gene CAG repeats (OR = 2.51; 95% CI = 1.06 to 5.94). We found a similar interaction between the SRD5A2 VV genotype and fewer AR gene CAG repeats (OR = 5.58; 95% CI = 1.86 to 16.71). Body mass index (BMI) modified the association of HCC with testosterone and SRD5A2 genotype; in men with low BMI, multivariate-adjusted ORs for the highest tertile of testosterone versus the lowest and the SRD5A2 VV genotype versus the LL genotype were 7.63 (95% CI = 2.13 to 27.27) and 8.64 (95% CI = 2.75 to 27.14), respectively. No clear associations were found between estradiol or testosterone-to-estradiol ratio and HCC.

CONCLUSIONS

Pathways involving androgen signaling may affect the risk of HBV-related HCC among men.

A school waterborne outbreak involving both Shigella sonnei and Entamoeba histolytica

In an outbreak of gastroenteritis affecting 730 students, Shigella sonnei and Entamoeba histolytica were isolated from the stool specimens of patients. Environmental investigations revealed the source of infection to be contamination of underground well water by sewage from a toilet. The outbreak ended with the closure of the well water supply. To avoid such problems, institutions and other groups that maintain their own wells, including schools and summer camps, need to be vigilant about maintenance and check for potential contamination.

Identification of acidic and aromatic residues in the Zta activation domain essential for Epstein-Barr virus reactivation

Epstein-Barr virus (EBV) lytic cycle transcription and DNA replication require the transcriptional activation function of the viral immediate-early protein Zta. We describe a series of alanine substitution mutations in the Zta activation domain that reveal two functional motifs based on amino acid composition. Alanine substitution of single or paired hydrophobic aromatic amino acid residues resulted in modest transcription activation defects, while combining four substitutions of aromatic residues (F22/F26/W74/F75) led to more severe transcription defects. Substitution of acidic amino acid residue E27, D35, or E54 caused severe transcription defects on most viral promoters. Promoter- and cell-specific defects were observed for some substitution mutants. Aromatic residues were required for Zta interaction with TFIIA-TFIID and the CREB-binding protein (CBP) and for stimulation of CBP histone acetyltransferase activity in vitro. In contrast, acidic amino acid substitution mutants interacted with TFIIA-TFIID and CBP indistinguishably from the wild type. The nuclear domain 10 (ND10) protein SP100 was dispersed by most Zta mutants, but acidic residue mutations led to reduced, while aromatic substitution mutants led to increased SP100 nuclear staining. Acidic residue substitution mutants had more pronounced defects in transcription activation of endogenous viral genes in latently infected cells and for viral replication, as measured by the production of infectious virus. One mutant, K12/F13, was incapable of stimulating EBV lytic replication but had only modest transcription defects. These results indicate that Zta stimulates viral reactivation through two nonredundant structural motifs, one of which interacts with general transcription factors and coactivators, and the other has an essential but as yet not understood function in lytic transcription.

Occupational exposure to wood, formaldehyde, and solvents and risk of nasopharyngeal carcinoma

Our objective was to evaluate the link between occupational exposures to wood dust, formaldehyde, and solvents and the development of nasopharyngeal carcinoma (NPC). A case-control study was conducted among 375 newly diagnosed cases of NPC in Taipei, Taiwan, and 325 community controls matched to cases on sex, age, and geographical residence (99 and 87% response rates, respectively). Most cases (>90%) were diagnosed with WHO Types 2 or 3 (nonkeratinizing and undifferentiated carcinomas), whereas the remaining cases were diagnosed with WHO Type 1 (squamous cell carcinomas). A complete occupational history was obtained via a personal interview and blindly assessed by an industrial hygienist for intensity and probability of exposure to wood dust, formaldehyde, and solvents. Information on socio-demographic characteristics, cigarette smoking, dietary consumption of nitrosamines, and other potential confounding factors was obtained via a personal interview. Blood specimens were tested for human leukocyte antigen class I/II genotypes, polymorphisms in cytochrome P450 2E1 genotype, and various anti-EBV antibodies known to be associated with NPC. Analysis was performed using logistic regression; relative risk (RR) estimates and 95% confidence intervals (CI) were calculated. Individuals exposed to wood dust had an adjusted RR of 1.7 (95% CI = 1.0-3.0). Those exposed to wood dust for >10 years had an adjusted RR of 2.4 (95% CI = 1.1-5.0; p(trend) = 0.02). Risk was strongest for those first exposed before the age of 25 years and those seropositive to EBV. Individuals exposed to formaldehyde were at a more modest and nonsignificant increased risk of NPC (RR = 1.4; 95% CI = 0.93-2.2). Those exposed to formaldehyde for >10 years had an adjusted RR of 1.6 (95% CI = 0.91-2.9). The association between formaldehyde and NPC was stronger in analyses restricted to EBV seropositive individuals (RR = 2.7; 95% CI = 1.2-5.9). However, no dose response was observed with increasing duration or cumulative use. No association was observed between solvent exposure and NPC (RR = 1.2; 95% CI = 0.86-1.7). Occupational exposure to wood dust is likely to be involved in the development of NPC, a finding that is consistent with the known link between wood exposure and nasal adenocarcinomas. Formaldehyde exposure is less clearly linked to NPC, whereas exposure to solvents is unlikely to be involved in NPC pathogenesis.

Association of aflatoxin B(1)-albumin adduct levels with hepatitis B surface antigen status among adolescents in Taiwan

Chronic hepatitis B virus (HBV) infection and aflatoxin B(1) (AFB(1)) exposure interact synergetically to induce hepatocellular carcinoma. One suggested mechanism for this interaction is the enhanced activation of AFB(1) in chronically HBV-infected individuals. Whereas no associations between chronic HBV infection and AFB(1)-albumin adducts were observed in several studies in adults, hepatitis B surface antigen (HbsAg)-positive children were found to have elevated adducts in Gambia. To assess the association between chronic HBV infection and AFB(1)-albumin adduct level in Taiwan, 200 junior high school adolescents from 20 townships were assayed for HBsAg and AFB(1)-albumin adducts. The mean AFB(1)-albumin adduct level was higher in HBsAg-positive compared with HBsAg-negative subjects. The association between HBsAg status and AFB(1)-albumin adducts remained after multivariate adjustment. This finding additionally supports the synergetic interaction between HBV and AFB(1), but the mechanism remains to be elucidated.

Effect of prolonged radiation exposure on the thyroid gland of residents living in 60Co-contaminated rebar buildings

PURPOSE

To evaluate prolonged low dose-rate gamma-exposure effects on the thyroid glands of residents living in 60Co-contaminated steel buildings.

MATERIALS AND METHODS

Physical examination and ultrasonography of the thyroid, determination of thyroid function and anti-thyroid microsomal antibodies were performed for 1346 residents. Ultrasound-guided aspiration cytology was done for thyroid nodules. The study subjects were stratified by age at examination (< or = 15 and > 15 years), sex and exposure dose to the body. Dose-response data on the prevalence of various thyroid diseases were analysed by the multiple logistic regression analysis.

RESULTS AND CONCLUSIONS

The prevalence of simple goitre was related to the exposure with a dose-response relationship for males of all ages, and for females of < or = 15 years. There was a biological gradient of thyroid cyst prevalence with the increase in exposure dose for females of all ages. The prevalence of elevated serum tri-iodothyronine level showed a dose-response relationship for males of < or = 15 years. A significant increase in thyroid abnormalities with dose was observed for males of all ages, and for females of < or = 15 years.

Polymorphism of the beta(2)-adrenoceptor in COPD in Chinese subjects

STUDY OBJECTIVES

To assess the frequencies of three polymorphisms at amino acid positions 16, 27, and 164 of the beta(2)-adrenoceptor (beta(2)-AR) gene and their effects on COPD patients.

DESIGN

Prospective, case-control study

PATIENTS

Sixty-five patients with COPD and 41 healthy subjects were included.

MEASUREMENTS

Polymorphisms of the beta(2)-AR coding block were delineated using an allele-specific polymerase chain reaction (PCR) approach. The allele-specific PCR technique was verified by direct dideoxy sequencing of PCR products. Pulmonary function tests were performed in all patients.

RESULTS

The Arg16 beta(2)-AR polymorphism was less prevalent in COPD patients than in healthy populations (p = 0.01). A significant correlation (p < 0.018) between the Gln27 beta(2)-AR polymorphism and FEV(1) percent predicted value was found. Patients with the Gln27 polymorphism had a higher percentage of low FEV(1) percent predicted than did patients with the GlnGlu and GluGlu variants.

CONCLUSIONS

The polymorphism of Gly16 may increase the patient's susceptibility to the development of COPD. The Gln27 beta(2)-AR polymorphism may be associated with the severity of COPD in a Chinese population.

Persistent hyperendemicity of hepatitis C virus infection in Taiwan: the important role of iatrogenic risk factors

The purpose of this study was to investigate determinants of endemic hepatitis C virus (HCV) infection within communities in Taiwan. A two-phase study, including a seroprevalence survey and a prevalent case-control study at the first phase, which has been published previously, and a follow-up seroconversion determination and an incident case-control study during the second phase, was carried out to evaluate correlates of persistent endemic HCV infection. At the first phase, a total of 12,021 men and 1,819 women who were 30-64 years old and living in seven townships in Taiwan were tested for the seroprevalence of antibodies to HCV (anti-HCV). In addition, a prevalent case-control study involving 272 HCV-positive cases and 282 seronegative controls identified from the anti-HCV testing was conducted to investigate risk factors associated with HCV prevalence. During the second phase, a total of 2,728 men and 834 women who were seronegative at recruitment participated in the 1-year prospective study on anti-HCV seroconversion. Subsequently, an incident case-control study based on 39 seroconverters and 81 persistently seronegative controls were carried out to elucidate determinants of HCV seroconvertion. Antibodies to HCV were tested by the second-generation enzyme immunoassay. Information on risk factors of HCV infection was collected from subject interviews. The prevalence of anti-HCV consistently increased with age (range 2.9-5.4%), whereas no apparent age trend was observed for anti-HCV seroconversion rate (range 0.9-1.7%). A striking geographical variation in seroprevalence and seroconversion rates of anti-HCV was observed in the study townships. Furthermore, a significant geographical correlation between HCV seroprevalence and seroconversion rates was noted (r = 0.962, P = 0.001). From the results of both prevalent and incident case-control comparisons, medical injections were found to be the main mode to sustain the persistent endemic state of HCV infection within a community (odds ratios for prevalent and incident case-control studies were 2.5 (95% CI = 1.7-3.6) and 3.1 (95% CI = 1.4-7.1), respectively. The data indicate that the basis for HCV transmission has already been existed in study areas and the iatrogenic risk factor tended to be the major determinant for sustaining persistent endemicity within a community.

Epidemiologic study of the prevalence and severity of myopia among schoolchildren in Taiwan in 2000

BACKGROUND AND PURPOSE

A nationwide survey was performed in 2000 to determine the prevalence and severity of myopia among schoolchildren in Taiwan and to compare these findings with the results of the last survey performed in 1995.

METHODS

We first divided the whole island into regions according to developmental grade scores and then sampled with the probability proportional to the size of the population within each stratum. A total of 10,889 students were enrolled, including 5,664 boys and 5,225 girls, with ages ranging from 7 to 18 years. The refractive status and corneal radius of each student were measured with an autorefractometer under cycloplegia and checked with retinoscopy. Axial length was measured using biometric ultrasound.

RESULTS

The myopia rate increased from 20% at 7 years, to 61% at 12 years, and 81% at 15 years. A myopic rate of 84% was found for schoolchildren aged 16 years through 18 years. The mean refractive index reached myopic status at the age of 8, and increased to -4.12 D in girls and -3.15 D in boys at the age of 18 years. The prevalence of high myopia (> -6.0 D) at the age of 18 years was 24% in girls and 18% in boys. The increase in axial length corresponded with the progression of myopia. The anterior chamber depth was slightly deeper from 7 years to 13 years and then remained stable. The lens thickness decreased from 7 years to 11 years. After age 15, further thickening of the lens was correlated with both age and severity of myopia. However, the corneal curvature was not related to age or severity of myopia. Girls had a higher prevalence and more severe degree of myopia than boys. Children in urban areas had a higher prevalence and more severe degree of myopia than children in rural areas.

CONCLUSION

The prevalence and severity of myopia in schoolchildren in Taiwan in 2000 increased compared to 1995, with the most severe increases occurring in younger age groups. Thus, preventing schoolchildren developing myopia at a young age may slow down the increase in severity of myopia in Taiwan.

Correlation of human papillomavirus 16 and 18 with cervical neoplasia in histological typing and clinical stage in Taiwan: an in-situ polymerase chain reaction approach

BACKGROUND AND OBJECTIVES

In situ polymerase chain reaction (ISPCR) promises to considerably enhance our ability to detect a few copies of target nucleic acid sequences in fixed tissues and cells. The aim of this study was to investigate cervical carcinoma to determine the human papillomavirus (HPV) types on paraffin-embedded tissue sections by ISPCR and standard in situ hybridization. The results will correlate the morphological characteristics of lesions with viral typing results.

METHODS

This study examined prevalence of HPV 16 and 18 DNA in biopsies from 85 cervical cancer patients by ISPCR, employing HPV 16, 18 consensus primers. There are 45 patients with squamous cell carcinomas, 13 with adenocarcinoma, 2 with adenosquamous carcinomas, 3 with small cell carcinomas, and 22 carcinoma in situ. The relation between the types of HPV detected, tumor type, and clinical stage were analyzed.

RESULTS

Fifty-two of 85 biopsies were HPV 16- or 18-positive, HPV 16 being the most prevalent type. Squamous cell carcinoma had a high prevalence of HPV 16 and adenocarcinoma had a high prevalence of HPV 18. HPV 18 was the predominant type among high clinical stage (III-IV) cases while HPV 16 and mixed HPV 16 with HPV18 were significantly correlated with low clinical stage (0-I-II).

CONCLUSION

Our results indicate that certain malignant cervical tumor phenotypes and stages correlate with specific HPV type, and that ISPCR is a sensitive and fast method to detect HPV in these patients.

Crystal structure of the transcription factor sc-mtTFB offers insights into mitochondrial transcription

Although it is commonly accepted that binding of mitochondrial transcription factor sc-mtTFB to the mitochondrial RNA polymerase is required for specific transcription initiation in Saccharomyces cerevisiae, its precise role has remained undefined. In the present work, the crystal structure of sc-mtTFB has been determined to 2.6 A resolution. The protein consists of two domains, an N-terminal alpha/beta-domain and a smaller domain made up of four alpha-helices. Contrary to previous predictions, sc-mtTFB does not resemble Escherichia coli sigma-factors but rather is structurally homologous to rRNA methyltransferase ErmC'. This suggests that sc-mtTFB functions as an RNA-binding protein, an observation standing in contradiction to the existing model, which proposed a direct interaction of sc-mtTFB with the mitochondrial DNA promoter. Based on the structure, we propose that the promoter specificity region is located on the mitochondrial RNA polymerase and that binding of sc-mtTFB indirectly mediates interaction of the core enzyme with the promoter site.

Association of blood arsenic levels with increased reactive oxidants and decreased antioxidant capacity in a human population of northeastern Taiwan

Arsenic is a notorious environmental toxicant known as both a carcinogen and an atherogen in human beings, but the pathogenic mechanisms are not completely understood. In cell culture studies, trivalent arsenic enhanced oxidative stress in a variety of mammalian cells, and this association may be closely associated with the development of arsenic-related diseases. To investigate the effect of arsenic exposure on oxidative stress in humans, we conducted a population study to determine the relationships of blood arsenic to reactive oxidants and antioxidant capacity at the individual level. We recruited 64 study subjects ages 42-75 years from residents of the Lanyang Basin on the northeast coast of Taiwan, where arsenic content in well water varies from 0 to > or = 3,000 microg/L. We used a chemiluminescence method, with lucigenin as an amplifier for measuring superoxide, to measure the plasma level of reactive oxidants. We used the azino-diethyl-benzthiazoline sulphate method to determine the antioxidant capacity level in plasma of each study subject. We determined arsenic concentration in whole blood by hydride formation with an atomic absorption spectrophotometer. The average arsenic concentration in whole blood of study subjects was 9.60 +/- 9.96 microg/L (+/- SD) with a range from 0 to 46.50 microg/L. The level of arsenic concentration in whole blood of study subjects showed a positive association with the level of reactive oxidants in plasma (r = +0.41, p = 0.001) and an inverse relationship with the level of plasma antioxidant capacity (r = -0.30, p = 0.014). However, we found no significant association (p = 0.266) between levels of plasma reactive oxidants and antioxidant capacity. Our results also show that the lower the primary arsenic methylation capability, the lower the level of plasma antioxidant capacity (p = 0.029). These results suggest that ingestion of arsenic-contaminated well water may cause deleterious effects by increasing the level of reactive oxidants and decreasing the level of antioxidant capacity in plasma of individuals. Persistent oxidative stress in peripheral blood may be a mechanism underlying the carcinogenesis and atherosclerosis induced by long-term arsenic exposure.

Reducing pressure drop in a baghouse using flow distributors

The pressure drop of ladder vanes in a baghouse could be reduced by decreasing the vane number and adjusting the inclined angle of the vane. Two types of flow distributors were utilized to test pressure drop caused by the structure of a baghouse. The pressure drops were measured by an inclined manometer under various filtration velocities. The purpose of this study is to understand the improvement effect of pressure drop saving for the traditional ladder vanes. Experimental results showed that the pressure drop of the Vane 3-1 configuration (flow distributor with three vanes perpendicular to the inlet flow) was higher than that of the Empty configuration (without flow distributors). The Vane 3-1 configuration could not reduce the pressure drop because of the barrier effect. By reducing the number and adjusting the angle of the vanes, the barrier effect was decreased, and the pressure drop of the Vane 2-1 configuration was much lower than that of the Vane 3-1 configuration. The largest difference in pressure drop between Vane 2-1 and Vane 3-1 was 1.702 cm w.g. at a filtration velocity of 4.17 cm/sec and, in terms of percentage, is 18.52% corresponding to a filtration velocity of 2.25 cm/sec. The improvement effect on the pressure drop saving for Vane 3-1 was significant.

Systemic lupus erythematosus complicated by recurrent spontaneous pneumothorax--a case report

Despite frequent pleuro-pulmonary involvement, spontaneous pneumothorax is rare in patients with systemic lupus erythematosus (SLE). Here, we report a 17-year-old female patient with SLE, complicated by multiple organs involvement. She initially presented with interstitial pneumonitis and pulmonary hemorrhage, followed by spontaneous pneumothorax and CNS involvement. The patient was treated with immunosuppressive agents, including steroid and cyclophosphamide pulse therapies. Spontaneous pneumothorax happened to her once again at a different location during treatment. After aggressive therapy, the disease activity of SLE gradually diminished, and pneumothorax had not recurred during the further follow-up. Therefore, the pneumothorax may occur in SLE patients with high disease activity.

Suprasellar and infrasellar craniopharyngioma with a persistent craniopharyngeal canal: case report and review of the literature

Craniopharyngiomas are usually confined to the sellar and suprasellar regions; infrasellar craniopharyngioma is rare. From an embryological point of view, this unusual localisation can be explained by Erdheim's theory that these tumours can arise anywhere along the craniopharyngeal canal (CPC). However, there has been no proof of this theory, because the CPC is usually obliterated during the 12th week of gestation. I present a case of supra- and infrasellar craniopharyngiomas with a persistent CPC. Imaging demonstrated an intimate relationship between the infrasellar tumour and the CPC, supporting Erdheim's view.

Familial risk of asthma among adolescents and their relatives in Taiwan

Although family studies have established that asthma has a hereditary basis, little evidence has been presented about the family risk of simple asthma (AS or nonatopic asthma) and asthma with other atopic diseases (AWAD or atopic asthma) after adjusting for potential risk factors. In this study, data were collected on demographic variables and a wide range of known risk factors for asthma. Study participants were asthmatic adolescents and controls, and their relatives. The role of a familial history of asthma and atopic diseases in predicting asthma risk among asthmatic adolescents and their relatives was evaluated in a population-based family study conducted in southern Taiwan. Asthma risk factor data were collected through telephone interviews with students' parents for 207 asthmatic adolescents 11-16 years of age, their 1600 relatives, and 207 nonasthmatic adolescents in the control group and their 1638 relatives. The results show (after adjusting potential confounders) that a family history of asthma is highly associated with asthma in adolescents. Having two or more family members with asthma was associated with a 3.4-fold (95% confidence interval [CI] = 1.0-12.0) increased risk of asthma among adolescents. Logistic regression was used to assess the effects of having an asthmatic relative and the effect of atopic diseases among relatives of cases. Having a family history of asthma and other atopic conditions, such as rhinitis and atopic dermatitis (adjusted odds ratio [AOR] = 3.64, 95% CI = 2.29-5.74 and AOR = 1.94, 95% CI = 1.53-2.46, respectively), was found to be a significant predictor of asthma in children. Along with a history of allergic rhinitis or atopic dermatitis, familial risks of asthma occurring in adolescents with and without other atopic diseases will be analyzed separately. A critical finding was the significant difference in a risk of asthma and atopic diseases among the relatives of asthma cases with atopic diseases and controls. However, for relatives of asthma cases without atopic diseases compared to control probands, AORs were highly significant for family history of asthma, but not for the family history of atopic diseases. These findings suggest that both forms of asthma may be hereditary, but there are differences in their modes of inheritance. Atopic status itself did not predispose a child to AS. A concomitant inheritance of a predisposition to asthma and atopic condition for AWAD cases was suggested.