Arabic validation of the Compulsive Internet Use Scale (CIUS)

Background

Areca nut is the seed of fruit oriental palm known as Areca catechu. Many adverse effects of nut chewing have been well documented in the medical literature. As these nuts are mixed with some other substances like tobacco and flavouring agents, it has been hypothesized that it might also cause some dependency symptoms among its users. Therefore, the objective of this study was to investigate dependency syndrome among areca nut users with and without tobacco additives and compare it with dependency associated with cigarette smoking among the male Pakistani population.

Methods

This was an observational cross sectional study carried out on healthy individuals, who were users of any one of the three products (areca nut only, areca nut with tobacco additives, cigarette smokers). Participants were selected by convenience sampling of people coming to hospital to seek a free oral check up. Information was collected about the socio-demographic profile, pattern of use and symptoms of dependency using the DSM-IV criteria for substance dependence. We carried out multiple logistic regressions to investigate association between socio-demographic profile, pattern of substance use and dependency syndrome.

Results

We carried out final analysis on 851 individuals, of which 36.8% (n = 314) were areca nut users, 28.4% (n = 242) were the chewers of areca with tobacco additives and 34.7% (n = 295) were regular cigarette smokers. Multivariate analyses showed that individuals using areca nut with tobacco additives were significantly more likely to have dependency syndrome (OR = 2.17, 95% CI 1.39-3.40) while cigarette smokers were eight times more likely to have dependency syndrome as compared to areca nut only users.

Conclusions

Areca nut use with and without tobacco additives was significantly associated with dependency syndrome. In comparison to exclusive areca nut users, the smokers were eight times more likely to develop dependence while areca nut users with tobacco additives were also significantly more likely to suffer from the dependence.     

炭黑颗粒诱发人B淋巴母细胞系遗传损伤的体外试验

目的 评价2种粒径炭黑诱发的人B淋巴母细胞的遗传损伤效应.方法 人B淋巴母细胞经终浓度为0(溶剂对照)、128、256、384、512 ug/ml的14、280 nm炭黑颗粒染毒24、48 h后,用微核试验、hprt基因突变试验和彗星试验进行检测.微核试验指标为微核率(MNR)、微核细胞率(MCR)、核芽(Buds)、核质桥(NPBs)、核分裂指数(NDI)和凋亡细胞.彗星试验指标为尾部DNA百分比(%tail ONA)和olive尾矩(OTM).hprt基因突变试验指标为基因突变率(Mf-hprt).结果 14 nm炭黑染毒48 h组,浓度为384、512 ug/ml时,%tail DNA、OTM分别为8.23%±0.19%、11.23%±0.42%和3.72±0.08、4.90±0.18,明显高于对照组(5.10%±0.08%和2.22±0.03),差异有统计学意义(P<0.01);凋亡细胞数分别为4.67±0.33、5.33±0.33,明显高于对照组(0.00±0.00),差异有统计学意义(P<0.05).hprt 基因突变试验结果 呈阴性.结论 14 nm超细炭黑细颗粒染毒48 h可诱发人B淋巴母细胞DNA损伤,但280 nm的炭黑颗粒未检测出类似效应.     

Biomonitoring Findings for Occupational Lead Exposure in Battery and Ceramic Tile Workers using Biochemical Markers,Alkaline Comet Assay,and Micronucleus Test Coupled with Fluorescence in Situ Hybridisation

Manufacture of lead-containing products has long been associated with various health risks. To get an insight into the related genotoxic risks, we conducted a biomonitoring study in 50 exposed workers and 48 matched controls using a battery of endpoints that sensitively detect the extent of genome instability in peripheral blood lymphocytes. The levels of primary DNA damage were estimated with the alkaline comet assay, while cytogenetic abnormalities were determined with the cytokinesis-block micronucleus (CBMN) cytome assay. Additionally, CBMN slides of 20 exposed and 16 control participants were subjected to fluorescence in situ hybridisation (FISH), coupled with pancentromeric probes to establish the incidence of centromere-positive micronuclei, nuclear buds, and nucleoplasmic bridges. Blood lead levels (B-Pb) were measured with atomic absorption spectrometry. To further characterise cumulative effects of occupational exposure, we measured erythrocyte protoporphyrin (EP) concentrations and delta-aminolevulinic acid dehydratase (ALAD) activity in blood. We also assessed the influence of serum folate (S-folate) and vitamin B₁₂ (S-B12) on genome stability. Compared to controls, occupationally exposed workers demonstrated significantly higher B-Pb (298.36±162.07 vs 41.58±23.02), MN frequency (18.71±11.06 vs 8.98±7.50), centromere positive MN (C+ MN) (8.15±1.8 vs 3.69±0.47), and centromere negative MN (C- MN) (14.55±1.80 vs 4.56±0.89). Exposed women had significantly higher comet tail intensity (TI) and length (TL) than control women. Furthermore, workers showed a positive correlation between age and nuclear buds and MN, between MN and years of exposure, and between S-B₁₂ levels and TI and ALAD activity, while a negative correlation was found between TI and B-Pb. These findings suggest that occupational settings in the manufacture of lead-containing products pose significant genotoxic risks, which calls for developing more effective work safety programmes, including periodical monitoring of B-Pb and genetic endpoints.Key words: blood lead, genetic endpoints, genome damage, human lymphocytes, MN-FISH     

Prevalence and related risk factors of areca quid chewing among junior high students in eastern Taiwan

Areca quid chewing is a serious problem in eastern Taiwan. The prevalence and related risk factors of areca quid chewing among junior high students were studied. Group 1 consisted of 896 non-aboriginal students and group 2 of 565 aboriginal students. The students were asked to fill out a questionnaire anonymously. Among the non-aboriginal students, 2.2% were found as current areca quid chewers, 16.4% had tried but not become regular users, and 2.2% had used it regularly and quit, whereas 9.7% of aboriginal students were current chewers, and 32.7% had tried it but had not become regular users, and 7.4% had used it regularly and quit. The prevalence of areca chewing is significantly different between boys and girls in the non-aboriginal group. A logistic regression analysis indicated that a non-aboriginal student who is a male, grows areca at home, is a tobacco smoker, an alcohol drinker, and has family members and close friends as chewers is more likely to chew areca quid than others. Aboriginal students who are chewers are likely to grow areca at home, are tobacco smokers and alcohol drinkers, and have family members and close friends as chewers. Based on the findings of the study, the need for a health promotion program was identified. Areca quid is not only detrimental to people's health, but also to the environment in which people live.     

氯化饮水中有机提取物对大鼠和人肝肿瘤细胞(HepG2)的遗传毒性及脂质过氧化作用

氯化消毒是城市饮水消毒常用的标准方法,然而氯化水中的有机物反应可生成一系列氯化副产物。许多研究表明,某些氯化副产物能诱发细菌突变,对哺乳动物有遗传毒性作用;流行病学调查表明,饮水氯化与人类某些癌症的发病率增加有关。Ｄ湖是武汉市重要的饮用水水源,自六十年代起,Ｄ湖就因为严重的有机物污染而变为“富营养化”湖。已有研究表明,Ｄ湖湖水及其氯化自来水的提取物具有致突变性［１］,饮用Ｄ湖自来水人群的肝、胃和肠癌死亡率明显高于对照人群［２］。本文研究了Ｄ湖氯化饮水提取物诱发体内和体外ＤＮＡ损伤的毒性作用以及对…     

氯化饮水中有机提取物对大鼠和人肝肿瘤细胞（HepG2）的遗传毒性及脂？…

应用体内,体外微核分析和单细胞凝胶电泳技术（慧星分析,ｃｏｍｅｔ分析）探讨氯化饮水的有机提取物对人肝肿瘤细胞和大鼠肝细胞,骨髓嗜多染红细胞的遗传损伤作用,并观察其对大鼠组织脂质过氧化物作用的影响。结果表明,氯化饮水低浓度提限物能诱导大鼠ＰＣＥｓ微核的增加,而高浓度提取物则能增加ＨｅｐＧ２微核的发生率。     

焦炉工外周血淋巴细胞遗传物质损伤水平的研究

目的　评价焦炉作业环境接触多环芳烃对焦炉工外周血淋巴细胞遗传物质的损伤。方法　应用彗星试验和外周血淋巴细胞胞质分裂阻滞微核检测法 ,评价 13 7名焦炉工和 50名非职业多环芳烃暴露对照人群外周血淋巴细胞DNA和染色体损伤水平 ;测定其尿中 1 羟基芘水平 ,评价个体多环芳烃暴露内剂量 ;收集个人职业史、年龄、性别、吸烟和饮酒状况等信息。结果　焦炉工尿中 1 羟基芘水平为 (5.76± 1.0 4) μmol/molCr ,明显高于对照组 [(0 .70± 0 .3 2 ) μmol/molCr]。焦炉工外周血淋巴细胞微核率和彗星尾矩分别为 8.0‰ (0 .0‰～ 3 0 .0‰ )和 2 .0 9(0 .3 1～ 75.41) ,均高于对照组 [3 .5‰ (0 .0‰～13 .0‰ )、1.0 5(0 .11～ 6.63 ) ] ,差异有显著性 (P <0 .0 5)。对照组中 ,吸烟个体彗星尾矩为 1.44(0 .2 3～6.63 ) ,高于不吸烟个体 [0 .81(0 .11～ 3 .47) ] ,差异有显著性 (P <0 .0 5)。按焦炉作业工龄将 13 7名焦炉工分为 0 .5～、16.0～和 2 2 .0～ (年 ) 3组 ,校正了年龄、性别、吸烟、饮酒和尿中 1 羟基芘水平后 ,焦炉工外周血淋巴细胞彗星尾矩分别为 1.3 4 (0 .3 1～ 3 7.84)、2 .3 2 (0 .49～ 52 .97)和 3 .2 0 (0 .45～ 75.41) ,有随焦炉作业工龄增加而增加的趋势。结论　在现有多环芳烃暴露水平     

Assessment of DNA damage in Japanese nurses handling antineoplastic drugs by the comet assay

To clarify genotoxic effects of occupational exposure to antineoplastic drugs in Japan, we examined DNA damage, assessed by the comet assay, in 121 female nurses and 46 female clerks working at three hospitals in the northeast of Japan. The comet assay is considered to be a sensitive and rapid method for DNA strand break detection in individual cells, and tail length and tail moment are used as the comet parameters. Concerning the basal characteristics, the 46 control subjects had higher rates of smoking and coffee-drinking habits and lower hemoglobin than the 121 nurses (p<0.05). The log-transformed tail length in the nurses was significantly longer than that in the control subjects after adjusting for possible covariates such as age and smoking habit (p<0.05). Also, the log-transformed tail length was significantly longer, in the 57 nurses who had handled antineoplastic drugs in the last six months, than that in the 46 control subjects (p<0.05); but, no significant difference in tail length or tail moment was seen between the two nurse groups with and without experience of handling hazardous drugs (p>0.05). These results suggest that Japanese nurses who have worked at hospitals using antineoplastic drugs may have a potential risk of DNA damage. To minimize this risk in Japan, use of biological safety cabinet and appropriate protective equipment, in addition to staff education and training, should be implemented in the healthcare environment.     

Biological monitoring of environment exposure to safrole and the Taiwanese betel quid chewing

A rapid and sensitive biological monitoring (BM) method for assessing exposure to the environmental carcinogen safrole has been developed. The method is an isocratic high-performance liquid chromatographic (HPLC) analysis of urinary dihydroxychavicol (DHAB) and eugenol, the urinary metabolites of safrole. Good linearity, precision, and accuracy were demonstrated. A recovery of 98.8 ± 5.4% (SD, n = 3) was found for DHAB and 84.1 ± 3.4% (n = 3) for eugenol. The quantitation limits of the method were 8 ng for DHAB and 10 ng for eugenol. The validity of the method was demonstrated by a linear dose-response relationship observed in rats given oral doses of safrole at 30, 75, and 150 mg/kg body weight. The method was also used to monitor the environmental exposure to the Taiwanese betel quid (TBQ) chewing, because TBQ used in Taiwan not only contains areca (betel) nut, slaked lime, and catechu but also Piper betle inflorescence or its leaves. Both of the latter have a high content of safrole. The feasibility of the method to monitor TBQ chewing was demonstrated by an analysis of 153 spot human urine samples. The results showed that the p value of the nonparametric group comparison was < 0.001 for DHAB and 0.832 for eugenol. The TBQ chewers also exhibited a significantly higher rate of urinary DHAB (but not eugenol) than the nonchewers with an odd ratio of 3.47 (95% CI, 1.61–7.51). However, when only the eugenol-positive subjects were taken into analysis, the ratio rose to 24.38 (95% CI, 3.00–197.90). Received: 12 November 2001/Accepted: 25 April 2002     

Sister chromatid exchange and oxidative DNA damage in paving workers exposed to PAHs

Paving workers are exposed during road paving to several polycyclic aromatic hydrocarbons (PAHs) contained in asphalt fumes. In this study early genotoxic and oxidative effects of exposure to bitumen fumes were evaluated in 19 paving workers and 22 controls. Environmental and biological monitoring of exposure was carried out, measuring, on personal air samples from exposed workers collected during three working days, the concentration of 14 PAHs and urinary OH-pyrene at the end of each of the three working days. Genotoxic effect was evaluated analysing sister chromatid exchange (SCE) frequency and direct-oxidative DNA damage by formamido-pyrimidine-glycosylase (Fpg)-modified comet assay on lymphocytes. Tail moment values from Fpg-enzyme treated cells (TMenz) and from untreated cells (TM) were used as parameters of direct and oxidative DNA damage, respectively. For each subject, the TMenz/TM ratio >2.0 was used to indicate the presence of oxidative damage. DNA damage was also evaluated analysing comet percentage. Personal air samples showed low level of total PAHs (2.843 microg m(-3)) with prevalence of 2-3 ring PAHs (2.693 microg m(-3)). Urinary OH-pyrene after work-shift of the three working days was significantly higher than that found at the beginning of the working week. SCE analysis did not show any difference between two groups while an oxidative DNA damage was found in 37% of exposed with respect to the absence in controls. Comet percentage was significantly higher (P = 0.000 ANOVA) in the exposed than in controls. The results demonstrate the high sensitivity of comet assay to assess early oxidative effects induced by exposure to bitumen fumes at low doses and confirm the suitability of urinary OH-pyrene as a biomarker of PAH exposure. In conclusion the study suggests the use of Fpg-modified comet test as a biomarker of early genotoxic effects and that of urinary OH-pyrene as a biomarker of PAH exposure to furnish indications in terms of characterization, prevention and management of risk in occupational exposure to mixtures of potentially carcinogenic substances.     

Application of cell sorting for enhancing the performance of the cytokinesis-block micronucleus assay

Among the numerous methods available to assess genotoxicity, the cytokinesis-block micronucleus (CBMN) assay is very popular due its relative simplicity and power to detect both clastogenic and aneugenic compounds. A problem with the CBMN assay is that all DNA damaging agents also inhibit the ability of cells to progress through mitosis, leading to a low number of binucleated cells (BNCs). One method to resolve this issue is to ensure a sufficient proportion of BNCs in the samples. In the current study, the applicability of a cell sorting system capable of isolating cell fractions containing abundant BNCs was investigated. Furthermore, to investigate the relationship between the cell division delay due to radiation exposure and the generation of BNCs and micronuclei (MN), we assessed a series of lag times between radiation exposure and addition of cytochalasin-B (Cyt-B). Cells from the human chronic myelogenous leukemia cell line K562 were exposed to X-rays (2 Gy and 4 Gy), and Cyt-B was subsequently added at 0, 6 and 12 h following irradiation. After treatment with Cyt-B for 24 h, the percentage of BNCs, the MN frequency and the cell cycle distribution were analyzed. In addition, cells displaying the DNA contents corresponding to BNCs were isolated and analyzed. The results indicate that applying the cell sorter to the CBMN assay increased the percentage of BNCs compared with the standard method. Thus, this technique is a promising way of enhancing the capacity of the CBMN assay.     

Changes in buccal micronucleus cytome parameters associated with smokeless tobacco and pesticide exposure among female tea garden workers of Assam,India

Assam is the highest tea producing state in India. A large number of workers are engaged in various units of tea industry. There are few reports on the health status of the tea garden workers. The present cytogenetic biomonitoring study was undertaken to investigate the genotoxic effect associated with workers in tea industries in southern Assam. Smokeless tobacco chewing along with betel nut is very common practice among the workers. Workers also get exposed periodically to mixture of pesticides. Employing buccal micronucleus cytome assay, exfoliated buccal cells were analyzed in 90 female tea garden and compared to 90 age and sex matched non-chewer control as well as 70 chewers who are not tea garden workers. Statistically significant (p < 0.001) increase in genotoxic and cell death parameters was observed in tea garden workers compared to both the control groups. The frequency of cell proliferation biomarkers was highest in the chewer controls whereas genotoxic and cell death parameters were highest in tea garden workers. Linear correlation analysis revealed strong positive correlation between the duration of occupation and the frequency of micronucleus (r = 0.597; p < 0.001) as well as cell death parameters (r = 0.588; p < 0.001). Amount of chewing also had significant positive correlation with micronucleus frequency (r = 0.243 or 5.9%; p < 0.05) and cell death parameters (r = 0.217; p < 0.05). A statistically significant decrease in total RBC count, haemoglobin content as well as acetylcholine esterase in the blood of exposed individuals was observed. The average BMI among the tea garden workers was relatively lower compared to the control group. Pesticide exposure and chewing areca nut along with smokeless tobacco use may be responsible for changes in cytome parameters in exfoliated buccal cells.     

Alkaline single cell gel electrophoresis of DNA fragments in biomonitoring for genotoxicity: an introductory study on healthy human volunteers

 Alkaline single cell gel electrophoresis (also known as the ‘comet assay’) is a rapid method for detecting DNA strand breaks in individual cells. Before the assay is used for biomonitoring in human populations the test conditions must be accurately characterised. Five healthy male volunteers donating capillary blood over a period of 20 weeks showed a fairly stable level of DNA damage in their lymphocytes. The values for tail moment and tail inertia, as evaluated by computerised image analysis of coded samples, were similar to those in lymphocytes from control mice but only 10% of those in lymphocytes from mice given cyclophosphamide (200 mg/kg b.wt.) 15–17 h before sacrifice. Inter- and intraindividual variations among the human subjects were related to both individual factors and laboratory conditions. When the comet assay is used for biomonitoring purposes it is suggested that each electrophoresis session should include not only the coded samples from the subjects, but also freshly isolated control cells and, in addition, cells that have been exposed to a well-characterised genotoxic insult. Received: 15 January 1996/Accepted: 8 March 1996     

Areca (betel) nut chewing habit among high-school children in the Commonwealth of the Northern Mariana Islands (Micronesia)

OBJECTIVE: To investigate the prevalence of its use by high-school children in Saipan in Micronesia. Usage of the areca nut is indigenous to south Asia and the western and south Pacific. Some serious health effects of areca nut chewing are recognized and the International Agency for Research on Cancer has recently classified regular use of areca nut as being carcinogenic to humans. Information on usage by young people, however, is scarce. METHODS: Data on consumption of areca nut were obtained by a self-administered questionnaire. Following an oral mucosal examination using WHO criteria any detectable oral mucosal diseases were recorded. FINDINGS: Of 309 schoolchildren surveyed (mean age 16.3 +/- 1.5 years), 63.4% claimed regular use, the highest level recorded in any school population survey. Significant oral diseases detected were oral leukoplakia in 13% and oral submucous fibrosis in 8.8% of children. CONCLUSION: These findings from Saipan suggest that areca nut chewing starts at a young age in Micronesia. As many users develop dependency this raises important concerns regarding its consequences for oral health.     

甲醛暴露工人XRCC1基因多态性与DNA损伤的关系研究

目的探讨甲醛暴露工人DNA修复基因XRCC1多态性与外周血淋巴细胞DNA损伤的关系。方法选择某密度板厂的151名甲醛暴露工人(暴露组)和某推土机厂的112名非甲醛暴露工人(对照组)为研究对象。用气相色谱法检测作业环境的甲醛浓度,应用彗星实验测定研究对象外周血淋巴细胞DNA损伤,以Olive尾距和彗星尾长反映DNA损伤水平,用PCR-RFLP方法分析XRCC1基因的多态性;用多元协方差分析调整工人的年龄、工龄、职业甲醛暴露及吸烟与饮烟情况,比较XRCC1基因不同基因型个体的Olive尾距和彗星尾长。结果使用多元协方差分析校正甲醛暴露工人的年龄、工龄、甲醛暴露水平和吸烟与饮酒情况后,携带Arg280His位点变异基因型个体的Olive尾距和彗星尾长(几何均值分别为4.30和13.42)均显著高于野生型基因型的个体(几何均值分别为3.38和11.71),差异均有显著性(Olive尾距:P<0.05,彗星尾长:P<0.01);未发现XRCC1基因其他3个位点的多态性与甲醛暴露工人Olive尾距和彗星尾长有显著关联。结论XRCC1基因Arg280His位点的多态性影响甲醛暴露工人的DNA损伤水平。     

Re-Examination of the Genotoxic Activity of Water Taken From the Songhua River in P. R. China

The Songhua River, in northeast China, has heavy organic contamination due to domestic sewage and industrial wastewater. Thus, it is important to further determine its genotoxic activity, which is a potential hazard for human health. Short-term genotoxic bioassays using Salmonella, the cytokinesis-block micronucleus cytome assay, and mouse liver cell comet assay were employed to further examine the genotoxic activity of diethyl ether extracts of water samples taken from the Songhua River. Ames test results showed that there were still frame-shift mutagens, both direct and indirect, in water samples at doses of 5.0 or 7.0 L water equivalent/plate. The mutagenicity seems to be less when compared with the results from 2002 to 2003. A dose–response relationship was also obtained between DNA damage in mouse liver cells by comet assay and micronuclei formation by CBMN assay. These results indicate that the water samples showed genotoxic activity with a mutagenic potency. 88 and 104 compounds, respectively, were identified in summer and winter water sample extracts by gas chromatography–mass spectrometry analysis. Four priority pollutants listed by the United States Environmental Protection Agency and six priority pollutants listed by the Chinese Environment Protection Agency were found in summer or winter water samples, respectively. The results indicate that the diethyl ether extracts of surface water samples taken from the Songhua River still show genotoxic activity (≥3.0 L water). The risks of potential carcinogenicity for human health in the Songhua River should be studied further.     

Applicability of the comet assay in evaluation of DNA damage in healthcare providers’ working with antineoplastic drugs: a systematic review and meta-analysis

Background: Unintended occupational exposure to antineoplastic drugs (ANDs) may occur in medical personnel. Some ANDs are known human carcinogens and exposure can be monitored by genotoxic biomarkers.

Objective: To evaluate the obstacles to obtaining conclusive results from a comet assay test to determine DNA damage among AND exposed healthcare workers.

Methods: We systematically reviewed studies that used alkaline comet assay to determine the magnitude and significance of DNA damage among health care workers with potential AND exposure. Fifteen studies were eligible for review and 14 studies were used in the meta-analysis.

Results: Under random effect assumption, the estimated standardized mean difference (SMD) in the DNA damage of health care workers was 1.93 (95% CI: 1.15–2.71, p < 0.0001). The resulting SMD was reduced to 1.756 (95% CI: 0.992–2.52, p < 0.0001) when the analysis only included nurses. In subgroup analyses based on gender and smoking, heterogeneity was observed. Only for studies reporting comet moment, I2 test results, as a measure of heterogeneity, dropped to zero. Heterogeneity analysis showed that date of study publication was a possible source of heterogeneity (B = ?0.14; p < 0.0001).

Conclusions: A mixture of personal parameters, comet assay methodological variables, and exposure characteristics may be responsible for heterogenic data from comet assay studies and interfere with obtaining conclusive results. Lack of quantitative environmental exposure measures and variation in comet assay protocols across studies are important obstacles in generalization of results.     

Sociocultural Factors that Affect Chewing Behaviors among Betel Nut Chewers and Ex-Chewers on Guam

Areca nut (betel nut) is chewed by an estimated 10% of the world''s population which is equivalent to about 600 million people. It is classified as a Group 1 carcinogen by the World Health Organization (WHO) and has been linked to various types of oral cancer. Chewing areca predominates in South and South East Asia, East Africa, and the Western Pacific and has important social and cultural implications. The purpose of the pilot study was twofold: (1) to examine sociocultural factors that affect why people on Guam chew betel nut, their chewing behaviors, perceptions of risks, probability of changing behaviors, and methods that could be used to reduce use or quit; and (2) to pilot two surveys (one for chewers and one for ex-chewers) to be used in a larger study in the future. A mixed methods design was employed that included surveys pertaining to their status (chewer or ex-chewer) and in-depth interviews. A total of 30 adults participated in this pilot study: adult betel nut chewers (n = 15) and ex-chewers (n = 15). Chewing betel nut is a learned behavior, embedded within the culture, and is viewed as an important cultural identifier. Socially, chewing is viewed as positive. Chewers stated that they were not as aware of health issues; however, ex-chewers stated health reasons for quitting.     

Effect of chronic tobacco-betel-lime "quid" chewing on human salivary secretions

Salivary flow rates by mechanical stimulation with forced spitting method and by chemical stimulation with 10% citric acid were determined in 25 healthy adult subjects with a history of chronic tobacco-betel-lime "quid" chewing and in 25 healthy control adults with no history of chewing. The chewers secreted more saliva as compared to nonchewers on chemical, but not on mechanical stimulation. The salivary amylase, potassium, and sodium levels were lower in chewers, but the reductions of the first two components only were significant. These reductions were thought to be due to increased salivary flow with its dilutional effect. There was no difference between the two groups with respect to salivary pH. The salivary flow rates by either method had significant positive correlation with the duration of chewing, but not with the amount of tobacco chewed. Salivary potassium was inversely correlated with the amount of tobacco chewed. It was concluded that chronic tobacco-betel-lime quid chewing induces excessive secretion of more watery saliva leading to a concomitant decrease in enzyme and electrolyte content. One or more of the following factors were considered to be operating in causing increased salivary flow in chewers effect of nicotine or tobacco on other constituents of the quid, chronic salivary gland hyperplasia, or chronic hypertrophy of the muscles of mastication.     

A Comprehensive Analysis of Plausible Genotoxic Covariates Among Workers of a Polyvinyl Chloride Plant Exposed to Vinyl Chloride Monomer

The aim of this study was to assess the frequency of chromosomal aberrations—including chromatid type aberrations (CTAs), chromosomal type aberrations, micronucleus (MN) comet assay, and XRCC1 399 Arg/Gln polymorphism—in peripheral blood lymphocytes of workers occupationally exposed to vinyl chloride monomer (VCM). A total of 52 workers and an equal number of controls were recruited into the study to explore the potential cytogenetic risk of occupational exposure to VCM. Questionnaires were administered to obtain details of habitual cigarette-smoking, alcohol-consumption pattern, and occupation, etc. The exposed subjects and controls were classified into two groups based on age (group I <40 years; group II ≥40 years), and exposed subjects were further classified based on exposure duration (>8 and ≥8 years). CTA, MN, and comet assay frequency were significantly greater in polyvinyl chloride (PVC) factory workers (p < 0.05) with long-duration work. CTA, MN, and comet assay values were found to be increased with age in exposed subjects as well as in controls, with exposed subjects showing a statistically greater degree. An extensively greater MN frequency was observed in smokers exposed to VCM than in the control group (P < 0.05). The mean tail length of exposed subjects was greater compared with controls. The study on XRCC1 399 Arg/gln polymorphism in PVC factory workers showed less significant difference in allele frequency compared with controls. In conclusion, this results of work provides evidence for an apparent genotoxic effect associated with VCM exposure. Our results reinforce the greater sensitivity of cytogenetic assays for biomonitoring of occupationally exposed populations. Statistics indicate that workers exposed to VCM are at carcinogenic risk and should be monitored for long-term adverse effects from their exposure.