The Québec BCG Vaccination Registry (1956–1992): assessing data quality and linkage with administrative health databases

Background

Vaccination registries have undoubtedly proven useful for estimating vaccination coverage as well as examining vaccine safety and effectiveness. However, their use for population health research is often limited. The Bacillus Calmette-Guérin (BCG) Vaccination Registry for the Canadian province of Québec comprises some 4 million vaccination records (1926-1992). This registry represents a unique opportunity to study potential associations between BCG vaccination and various health outcomes. So far, such studies have been hampered by the absence of a computerized version of the registry. We determined the completeness and accuracy of the recently computerized BCG Vaccination Registry, as well as examined its linkability with demographic and administrative medical databases.

Methods

Two systematically selected verification samples, each representing ~0.1% of the registry, were used to ascertain accuracy and completeness of the electronic BCG Vaccination Registry. Agreement between the paper [listings (n?=?4,987 records) and vaccination certificates (n?=?4,709 records)] and electronic formats was determined along several nominal and BCG-related variables. Linkage feasibility with the Birth Registry (probabilistic approach) and provincial Healthcare Registration File (deterministic approach) was examined using nominal identifiers for a random sample of 3,500 individuals born from 1961 to 1974 and BCG vaccinated between 1970 and 1974.

Results

Exact agreement was observed for 99.6% and 81.5% of records upon comparing, respectively, the paper listings and vaccination certificates to their corresponding computerized records. The proportion of successful linkage was 77% with the Birth Registry, 70% with the Healthcare Registration File, 57% with both, and varied by birth year.

Conclusions

Computerization of this Registry yielded excellent results. The registry was complete and accurate, and linkage with administrative databases was highly feasible. This study represents the first step towards assembling large scale population-based epidemiological studies which will enable filling important knowledge gaps on the potential health effects of early life non-specific stimulation of the immune function, as resulting from BCG vaccination.     

Hodgkin lymphoma risk: role of genetic polymorphisms and gene-gene interactions in DNA repair pathways

DNA repair variants may play a potentially important role in an individual's susceptibility to developing cancer. Numerous studies have reported the association between genetic single nucleotide polymorphisms (SNPs) in DNA repair genes and different types of hematologic cancers. However, to date, the effects of such SNPs on modulating Hodgkin lymphoma (HL) risk have not yet been investigated. We hypothesized that gene-gene interaction between candidate genes in direct reversal, nucleotide excision repair (NER), base excision repair (BER) and double strand break (DSB) pathways may contribute to susceptibility to HL. To test this hypothesis, we conducted a study on 200 HL cases and 220 controls to assess associations between HL risk and 21 functional SNPs in DNA repair genes. We evaluated potential gene-gene interactions and the association of multiple polymorphisms in a chromosome region using a multi-analytic strategy combining logistic regression, multi-factor dimensionality reduction and classification and regression tree approaches. We observed that, in combination, allelic variants in the XPC Ala499Val, NBN Glu185Gln, XRCC3 Thr241Me, XRCC1 Arg194Trp, and XRCC1 399Gln polymorphisms modify the risk for developing HL. Moreover, the cumulative genetic risk score revealed a significant trend where the risk for developing HL increases as the number of adverse alleles in BER and DSB genes increase. These findings suggest that DNA repair variants in BER and DSB pathways may play an important role in the development of HL.     

The effect of two types of sms-texts on the uptake of screening mammogram: a randomized controlled trial

ObjectiveTo compare the effect of two different types of short text message service (SMS-text) reminders on the uptake of screening mammogram.MethodsA randomized controlled trial was conducted in 2010 among females aged between 40 and 75, benefiting from the Health Insurance Plan at the American University of Beirut, whose cell phone numbers were available in their electronic medical records, and who did not do a mammogram in the past 2 years. The sample (n = 385) was randomly divided into two subgroups. The first subgroup (n1 = 192) received a general SMS-text inviting its members to do a mammogram while the second subgroup (n2 = 193) received an additional informative SMS-text informing them about the benefits of mammogram screening.Results30.7% (59) of subgroup 1 and 31.6% (61) of subgroup 2 underwent a mammogram screening test during the 6 months follow up interval post-intervention (Chi-square test, p-value ≥ 0.05). There was no difference between the response rates in the two subgroups.ConclusionA brief invitation SMS-text message for screening mammogram was found to be as effective as a detailed informative one.     

Chronic obstructive pulmonary disease among lung cancer-free smokers: The importance of healthy controls

Background

The prevalence of chronic obstructive pulmonary disease (COPD) in smokers enrolled as “healthy” controls in studies is 10–50%. The COPD status of ideal smoker populations for lung cancer case-control studies should be checked via spirometry; however, this is often not feasible, because no medical indications exist for asymptomatic smokers to undergo spirometry prior to study enrollment. Therefore, there is an unmet need for robust, cost effective assays for identifying undiagnosed lung disease among asymptomatic smokers. Such assays would help excluding unhealthy smokers from lung cancer case-control studies.

骨髓间充质干细胞移植对心肌梗死大鼠血管新生和内皮功能的影响

目的:通过检测血特异的内皮细胞标记物管性假血友病因子,观察骨髓间充质干细胞移植治疗急性心肌梗死后大鼠局部新生血管情况,并探讨内皮血管功能指标E-选择素与新生血管的关系。方法:实验于2005-09/2006-06在唐山工人医院中心实验室完成。①选用清洁级健康近交系SD大鼠40只,随机数字表法分为假手术组、模型对照组、干细胞移植组、细胞培养基组,10只/组。②另取1只大鼠用于骨髓间充质干细胞的提取。大鼠处死后无菌条件下分离股骨和胫骨,应用密度梯度法分离培养骨髓间充质干细胞。待细胞80%贴满培养瓶底时,用乙二胺四乙酸和胰蛋白酶混合消化传代。将50mg/L4,6-二脒-2-苯基吲哚加入第3代细胞培养基中,制成细胞悬液备用。③术前各组大鼠均行气管插管,建立急性心肌梗死模型,以远端供血区心肌组织颜色苍白、心电图检测Ⅱ导联ST段持续抬高为模型建立成功的标志。假手术组仅开胸予以前降支穿线但不结扎。④造模成功后1～3h,干细胞移植组用微量注射器吸取4,6-二脒-2-苯基吲哚标记好的第3代骨髓间充质干细胞悬液50μL,直接注入梗死区边缘心肌组织。细胞培养基组按干细胞移植组的方法于相同部位注射等量无血清DMEM低糖培养基(pH值为6.9),模型对照组仅制作心肌梗死模型不作其他处理,假手术组亦不作其他处理。⑤造模后2,4周各组处死半数大鼠,切取心脏组织,于梗死边缘区心肌组织制作切片,荧光显微镜下观察4,6-二脒-2-苯基吲哚标记的供体细胞。链霉亲和素免疫组化法检测心肌细胞中血管性假血友病因子评估新生血管情况,酶联免疫吸附法测定血清E-选择素含量,评估内皮功能。结果:40只大鼠均进入结果分析。①各组大鼠心脏标本4,6-二脒-2-苯基吲哚标记移植细胞存活状况:骨髓干细胞移植治疗后,荧光显微镜下可见成团和散在的DAPI阳性细胞,其余3组大鼠心脏标本中均未见荧光细胞。②各组大鼠血清E-选择素的检测:心肌梗死后2,4周模型对照组及细胞培养基组E-选择素明显增高,与假手术组比较差异显著[2周:(36.04±4.47),(34.10±2.04),(13.37±3.01)μg/L;4周:(33.02±4.78),(33.96±5.18),(13.94±2.87)μg/L,P<0.01],干细胞组移植组E-选择素较模型对照组明显降低[2周:(24.29±3.51),(36.04±4.47)μg/L;4周:(17.45±3.22),(33.02±4.78)μg/L,P<0.05]。③各组大鼠心肌组织血管性假血友病因子表达情况:链霉亲和素免疫组化法显示,造模后2周干细胞移植组心肌细胞血管性假血友病因子呈强阳性表达,模型对照组和细胞培养基组血管性假血友病因子表达减弱。造模后4周干细胞移植组心肌细胞血管性假血友病因子表达仍呈强阳性,模型对照组和细胞培养基组血管性假血友病因子表达有减弱趋势。结论:①移入的骨髓间充质干细胞存活。②骨髓干细胞移植治疗实验性大鼠心肌梗死模型后,可提高心肌细胞血管性假血友病因子水平,促进局部血管新生。③移植后心肌梗死大鼠血清中E-选择素的降低,可能与其参与血管新生有关,同时也提示骨髓干细胞移植不会诱发E-选择素增高而加重动脉硬化。     

Exposure to ethylene glycol monomethyl ether: clinical and cytogenetic findings

Glycol ethers are known reproductive and developmental toxins in laboratory animals, but little is known about their genotoxic effects in humans. In the current article, the authors tested the hypothesis that human in utero exposure to ethylene glycol monomethyl ether (EGME) is associated with the development of specific congenital anomalies and elevated levels of chromosome aberrations. The authors conducted a clinical and cytogenetic evaluation of 41 offspring of 28 females occupationally exposed to EGME for an average duration of 4.6 yr. Six offspring of 5 women who were occupationally exposed to EGME during pregnancy exhibited characteristic dysmorphic features that were not observed in 35 offspring of 23 women who worked in the same facility, but who were not pregnant at the time of exposure. Persistent cytogenetic damage was observed exclusively in all 6 in-utero-exposed offspring, but not in their 12 match non-in-utero-exposed controls. The study characterizes EGME as a human teratogen, as indicated by the prevalence of characteristic dysmorphic features and persistent cytogenetic damage in individuals exposed in utero to this chemical.     

Inhibitory effect of black tea on the growth of established skin tumors in mice: effects on tumor size, apoptosis, mitosis and bromodeoxyuridine incorporation into DNA

Female CD-1 mice were initiated with a single topical application of 7,12-dimethylbenz[a]anthracene and promoted with 12-O- tetradecanoylphorbol-13-acetate. Mice with established papillomas were then treated with black tea or decaffeinated black tea (approximately 4 mg tea solids/ml) as the sole source of drinking fluid for 11-15 weeks. In four separate experiments, oral administration of black tea inhibited the growth of papillomas (increase in tumor volume/mouse) by an average of 35%, 37%, 41% and 48%, respectively. Studies with decaffeinated black tea gave inconsistent results. In one experiment, administration of decaffeinated black tea inhibited papilloma growth (increase in tumor volume/mouse) by 27%, but in two additional experiments papilloma growth was stimulated by 14% and 193%, respectively. In a separate experiment, skin tumors were generated by treating SKH-1 female mice with ultraviolet B light (UVB; 30 mJ/cm2) twice weekly for 22 weeks, after which UVB administration was stopped. Tumors were allowed to develop during the following 13 weeks, and tumor- bearing mice were then treated with black tea (6 mg/ml tea solids) as the drinking fluid for 11 weeks. In this experiment, tumor growth (increase in tumor volume/mouse) was inhibited by 70%. Histological examination revealed that tea-treated mice had a 58% decrease in the number of nonmalignant tumors (primarily keratoacanthomas)/mouse and a 54% decrease in the number of squamous cell carcinomas/mouse. In addition, administration of black tea decreased the volume per tumor by 60% for nonmalignant tumors and by 84% for carcinomas. Mechanistic studies with tumors from these mice revealed that administration of black tea decreased the bromodeoxyuridine labeling index in squamous cell papillomas, keratoacanthomas and squamous cell carcinomas by 56%, 45% and 35%, respectively, and the apoptosis index was increased by 44%, 100% and 95%, respectively. Administration of black tea decreased the mitotic index in keratoacanthomas and squamous cell carcinomas by 42% and 16%, respectively. The results indicate that oral administration of black tea to tumor-bearing mice inhibited proliferation and enhanced apoptosis in nonmalignant and malignant skin tumors.      

The 399Gln polymorphism in the DNA repair gene XRCC1 modulates the genotoxic response induced in human lymphocytes by the tobacco-specific nitrosamine NNK

DNA repair plays a critical role in protecting the genome of the cell from the insults of cancer-causing agents such as those found in tobacco smoke. Reduced DNA repair capacity would, therefore, constitute a significant risk factor for smoking-related cancers. Recently, a number of polymorphisms in several DNA repair genes have been discovered, and it is possible that these polymorphisms may affect DNA repair capacity and thus modulate cancer susceptibility in exposed populations. In the current study, we explored the relationship between two polymorphisms in the DNA repair gene XRCC1 (polymorphisms in codons 194 and 399) and the genotoxic response induced by the tobacco-specific nitrosamine, 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK). The sister chromatid exchange (SCE) assay was used as a marker of genetic damage. Our results, using whole blood cultures from 47 volunteers, indicated that treatment of cells with 0.24, 0.72 and 1.44 mM of NNK induced a concentration-dependent increase in the mean number of SCE (P<0.001). There was a significant difference (P<0.05) in response to NNK treatment between cells from individuals with the 399Gln allele (either homozygous or heterozygous) and cells from individuals with the homozygous 399 Arg/Arg genotype. Treatment of cells that have the 399Gln allele with 0.24, 0.72 and 1.44 mM NNK resulted in 22.8, 35.8 and 52.8% increases in NNK-induced SCE, respectively. Treatment of cells with the 399 Arg/Arg genotype using the same NNK concentrations resulted in 16.0, 15.5 and 32.6% increases in NNK-induced SCE, respectively. In contrast, no significant difference in NNK-induced SCE was observed between cells with the codon 194 Arg/Arg genotype and cells with the codon 194 Arg/Trp genotype at all concentrations of NNK tested. These data suggest that the Arg399Gln amino acid change may alter the phenotype of the XRCC1 protein, resulting in deficient DNA repair. Our study underscores the important role of polymorphisms in DNA repair genes in influencing the genotoxic responses to environmental mutagens, and justifies additional studies to investigate their potential role in susceptibility to cancer.     

Effect of green tea on p53 mutation distribution in ultraviolet B radiation-induced mouse skin tumors

In the present study, administration of green tea to SKH-1 mice, via the drinking fluid, was found to significantly reduce the incidence and volume of ultraviolet B (UVB) radiation-induced skin tumors. Thirty-six skin tumors induced by UVB and 32 skin tumors induced by UVB, in mice treated with green tea in their drinking water, were collected and examined for the presence of mutations in the p53 gene. Polymerase chain reaction products from p53 exons 5-8 were screened by single- strand conformation polymorphism and direct sequence analyses. Eight of 36 UVB-induced tumors contained nine p53 mutations, with four in exon 5 and five in exon 8. In contrast, nine of 32 UVB-induced tumors in mice treated with green tea contained 11 p53 mutations, with two in exon 5, five in exon 6 and four in exon 8. All of the p53 mutations occurred at dipyrimidine sequences. These results were further corroborated by p53 immunohistochemistry. The most frequent mutations were C-->T or T-->C transitions, which are consistent with the genetic alterations caused by UVB exposure. Interestingly, mutations found in exon 6 of the p53 gene occurred only in tumors from the UVB/green tea group. Thus, the tumors observed in UVB/green-tea-treated mice have a different exon distribution of p53 mutations than tumors obtained from mice treated with UVB alone.