The Relationship Between Air Pollution and Lung Cancer in Nonsmokers in Taiwan

Introduction

For never-smokers (smoked <100 lifetime cigarettes), lung cancer (LC) has emerged as an important issue. We aimed to investigate the effects of prevalence changes in tobacco smoking and particulate matter (PM) 2.5 (PM_2.5) levels on LC in Taiwan, in relation to contrasting PM_2.5 levels, between Northern Taiwan (NT) and Southern Taiwan (ST).

Quantitative immunofluorescence assay for cyclobutyldithymidine dimers in individual mammalian cells

An indirect immunofluorescence procedure was developed for themeasurement of cyclobutyl dithymidine dimers in DNA of individualSyrian hamster embryo cells using a specific monoclonal antibody.A fluorescein-labeled secondary antibody and a fluorochromewhich binds to DNA were used to measure the photoproduct andtotal DNA in the same nucleus. Fluorescence intensity was quantitatedwith a computer-assisted microfluorometric system which wascalibrated with a uranyl oxide impregnated glass slide. Similardose-response curves, i.e. normalized fluorescence intensityplotted as a function of dose of germicidal irradiation, wereobtained with two different cell types. Normalized fluorescenceintensity per nucleus was related to thymidine dimer contentwith a competitive enzyme-linked imnmunosorbent assay usingDNA isolated from cells given doses of germicidal irradiationidentical to those used in the immunofluorescence assay. Thymidinedimer levels produced by 10 J/m² of germicidal irradiation (8x10⁵/nucleus)and which allow for 15–30% cell survival can readily bedetected. The specific monoclonal antibody was labeled withtritium and used in the immunofluorescence assay to relate thenumber of antibodies bound to the number of thynudine dimersper cell. The data revealed that 45% of the thymidine dimersin cells exposed to 100 J/m² of germicidal irradiation and essentiallyall the T<>T in cells receiving 20 J/m² were being detectedin the indirect immunofluorescence assay. This technique canprovide a sensitive means for measuring various types of DNAdamage in individual cells given that the appropriate probesare available. It can be especially useful for monitoring occupationallyor environmentally exposed populations where usually only smallsamples of cells or tissues are available.     

Conceptual problems in establishing the critical concentration of cadmium in human kidney cortex

The definition of the "critical concentration" for cadmium is compared with the concepts used to establish this measure in some recent publications. The term has not been clearly defined on a population basis and this has given rise to certain confusion. Different groups of investigators therefore have arrived at different estimates of the "critical concentration" for cadmium in human kidney cortex. A new measure, the "population critical concentration" (PCC) with a clearly defined response rate, is suggested. A reanalysis of the published data indicates that the PCC-10 (10% response rate) for cadmium in kidney cortex is likely to be in the range 180-220 micrograms/g and the PCC-50 is likely to be about 25% higher.     

Evaluation of serum type III procollagen peptide as an exposure marker in retired coal workers

Serum type III procollagen peptide (PIIIP), a degradation product of the type III collagen precursor, has been put forward as an exposure marker for mineral dust. We evaluated PIIIP levels as a marker of exposure to and effects of coal dust in retired coal miners (n = 104). To this end: (a) the individual cumulative dust exposure was calculated from job-exposure matrices, and (b) in addition to routine chest radiography (CR) of all miners according to the criteria of the International Labour Organisation (ILO), a subgroup (n = 46) was screened by high-resolution computed tomography (HRCT). Profusion score (CR and HRCT) tended to increase with cumulative dust exposure, even in the absence of CR evidence for pneumoconiosis (i.e. CR , 0/1, n = 35). In contrast to our previous findings in active miners, PIIIP levels were not increased in miners as compared with non-dust-exposed controls (n = 29), and no differences were observed between miners without (ILO = 0/0) and miners with coal workers' pneumoconiosis (CWP; ILO 0/1). No trend in PIIIP versus pneumoconiosis stage was present, either by CR or by the more sensitive HRCT score. PIIIP was also unrelated to any lung function parameter (FEV₁, FVC, impedance, diffusion capacity). Age, medication, medical history and smoking habits had no significant effect on PIIIP levels. In the miners with CWP (i.e. ILO > 0/0, n = 28) a significant negative correlation was present between PIIIP values and (log) cumulative dust exposure. This decrease in serum PIIIP levels with increasing cumulative exposure may be due to chronic adaptive changes in type III collagen deposition and/or breakdown. Other relations between exposure and PIIIP were not observed. In conclusion, the present findings do not support the use of serum type III procollagen peptide as a marker of exposure to and (early) interstitial or respiratory effects of coal dust.     

预防医学专业教学改革研究

预防医学旨在提高公共卫生健康水平,预防和控制疾病的发生。在市场经济体制逐步发展与完善的过程中,预防医学专业面临较大的冲击,为适应医学模式的转变,本文从调整培养目标,修订教学计划;调整和充实预防医学教学内容;加强师资队伍建设;改进教学方式和方法及编写具有特色的教学大纲等方面对预防医学教学的改革进行了研究。     

Transport and removal of viruses in saturated sand columns under oxic and anoxic conditions – Potential implications for groundwater protection

To protect groundwater as a drinking water resource from microbiological contamination, protection zones are installed. While travelling through these zones, concentrations of potential pathogens should decline to levels that pose no risks to human health. Removal of viruses during subsurface passage is influenced by physicochemical conditions, such as oxygen concentration, which also affects virus survival. The aim of our study was to evaluate the effect of redox conditions on the removal of viruses during sand filtration. Experiments in glass columns filled with medium-grained sand were conducted to investigate virus removal in the presence and absence of dissolved oxygen. Bacteriophages MS2 and PhiX174, as surrogates for human enteric viruses were spiked in pulsed or in continuous mode and pumped through the columns at a filter velocity of about 1 m/d. Virus breakthrough curves were analyzed by calculating total viral elimination and fitted using one-dimensional transport models (CXTFIT and HYDRUS-1D). While short-term experiments with pulsed virus application showed only small differences with regard to virus removal under oxic and anoxic conditions, a long-term experiment with continuous dosing revealed a clearly lower elimination of viruses under anoxic conditions. These findings suggest that less inactivation and less adsorption of viruses in anoxic environments affect their removal. Therefore, in risk assessment studies aimed to secure drinking water resources from viral contamination and optimization of protection zones, the oxic and anoxic conditions in the subsurface should also be considered.     

High-Resolution Melting Assay (HRMA) is a Simple and Sensitive Stool-Based DNA Test for the Detection of Mutations in Colorectal Neoplasms

BackgroundStool-based DNA testing for colorectal cancer is becoming a favored alternative to existing DNA screening tests. However, current methods of analysis often become more complicated and costly with increased sensitivity. The high-resolution melting assay (HRMA) is a simple and rapid mutation scanning method with low cost and superb accuracy. In this study, we verified the accuracy of HRMA for screening KRAS/TP53 mutations in stool-isolated DNA from patients with colorectal cancer.Materials and MethodsComparing to direct DNA sequencing, the accuracy of HRMA was verified by detecting KRAS/TP53 mutations in 2 independent stages. In study stage I, both tissue and stool samples from colorectal neoplasm patients were analyzed. In study stage II, stool samples from patients with colorectal neoplasms, and normal controls in clinical screening settings were examined.ResultsIn study stage I, the HRMA identified 14 of 17 target mutations (82.4%) in stools from cancer patients, and 4 of 5 (80.0%) target mutations in stools from advanced adenoma patients. The mutation detection rate in fecal samples (45.0%; 18/40) and referred tissue samples (55.0%; 22/40) was highly consistent (κ = 0.79). The HRMA detected 1% mutant DNA in a background of wild type DNA. In study stage II, the HRMA assay detected 58.8% (20/34) mutations in tumor samples, 41.5% (17/41) in advanced adenomas samples, and 3.33% (2/60) in age-matched normal control samples. The results from HRMA and DNA sequencing revealed 100% sensitivity and specificity in both tissue and stool samples.ConclusionHRMA is a simple, reliable, and sensitive method for detecting DNA mutations in the stool samples from patients with colorectal neoplasms.