RESUMEN
N-nitrosodimethylamine (NDMA) is a chloramine disinfection by-product, and its formation in drinking waters can increase due to the addition of cationic polydiallyldimethylammonium chloride (polyDADMAC). PolyDADMAC is a cationic polymer added as a coagulant or coagulant aid to enhance turbidity removal during sedimentation and filtration. This paper answers two central questions to understanding the nature of the NDMA precursors in polyDADMAC. First, what is the reactivity of different molecular weight (MW) fractions of polyDADMAC with chloramines? NDMA formation potential (NDMAFP) and kinetic experiments with chloramines were conducted for non-fractionated (raw) and size-excluded fractions (<3K, 3-10K, and >10K Da.) of polyDADMAC. The lower MW fraction (<3K Da.) of polyDADMAC solutions was responsible for forming 64⯱â¯6% of the NDMA, despite containing only 8.7 and 9.8% of the carbon or nitrogen present in the bulk polymer. The chloramine demand kinetics of the lowest MW fraction were also >2× faster than the higher MW fractions. Therefore, in a water treatment application the lower MW polyDADMAC likely contributes to most of the NDMA attributed to the use of polyDADMAC. The second question was: can 1H and 13C nuclear magnetic resonance spectroscopy (NMR) be used to characterize the molecular structures in polyDADMAC that react with chloramines? A peak for 1H NMR dimethylamine (DMA), a known low MW NDMA precursor, was found in a commercial polyDADMAC solution and decreased upon chloramination. The estimated DMA alone could not account for the observed NDMAFP, indicating the presence of other low MW precursors. Diffusion order spectroscopy (DOSY) NMR also showed multiple lower MW organics in polyDADMAC that change upon chloramination, including a 1.5× decrease in MW, suggesting chloramines cleave CC or CN bonds. These reactions may produce intermediates responsible for NDMA formation. Polymer manufacturers could use NMR to synthesize polyDADMAC with less DMA and other low MW compounds that produce NDMA upon chloramination.
Asunto(s)
Agua Potable , Contaminantes Químicos del Agua , Purificación del Agua , Dimetilnitrosamina , Desinfección , Peso MolecularRESUMEN
Certain unregulated disinfection byproducts (DBPs) are more of a health concern than regulated DBPs. Brominated species are typically more cytotoxic and genotoxic than their chlorinated analogs. The impact of granular activated carbon (GAC) on controlling the formation of regulated and selected unregulated DBPs following chlorine disinfection was evaluated. The predicted cyto- and genotoxicity of DBPs was calculated using published potencies based on the comet assay for Chinese hamster ovary cells (assesses the level of DNA strand breaks). Additionally, genotoxicity was measured using the SOS-Chromotest (detects DNA-damaging agents). The class sum concentrations of trihalomethanes, haloacetic acids, and unregulated DBPs, and the SOS genotoxicity followed the breakthrough of dissolved organic carbon (DOC), however the formation of brominated species did not. The bromide/DOC ratio was higher than the influent through much of the breakthrough curve (GAC does not remove bromide), which resulted in elevated brominated DBP concentrations in the effluent. Based on the potency of the haloacetonitriles and halonitromethanes, these nitrogen-containing DBPs were the driving agents of the predicted genotoxicity. GAC treatment of drinking or reclaimed waters with appreciable levels of bromide and dissolved organic nitrogen may not control the formation of unregulated DBPs with higher genotoxicity potencies.
Asunto(s)
Bromuros , Purificación del Agua , Animales , Células CHO , Cricetulus , Desinfectantes , Desinfección , Contaminantes Químicos del AguaRESUMEN
OBJECTIVES: Recent studies propose the role of gonadotropins in the development and growth of endometrial carcinoma. The present research was undertaken to establish the expression of human chorionic gonadotropin (hCG), gonadotropin-releasing hormones 1 (GnRH1 and GnRH2, respectively) and their receptors in endometrial hyperplasias and carcinoma. MATERIAL AND METHODS: The expression of analyzed genes in endometrial carcinoma and hyperplasia with and without atypia was evaluated using reverse transcriptase polymerase chain reaction and immunohistochemistry. RESULTS: The results of the experiments demonstrated the presence of hCG and GnRH1 at both messenger RNA and protein levels in endometrial carcinoma and atypical hyperplasia. Noncancerous tissue and hyperplasia without atypia demonstrated the lack of these gene coexpressions. The expression of GnRH2, LH/hCGR, and GnRHRs was heterogeneous, and the study molecules were found only in part of the analyzed tissues. The presence of hCG and GnRH1 and their receptors in cancer tissue and atypical hyperplasia suggests autocrine/paracrine action of hormones regulating the endometrial carcinoma cell proliferation. CONCLUSIONS: The interaction between the hCG and LH/hCGR in endometrial tissue might stimulate cell growth and promote neoangiogenesis, whereas GnRHs, by binding to their receptors, could be responsible for the antiproliferative effect and stimulation of apoptosis. The identification of differences in the expression profile of the analyzed genes could be relevant for better understanding of the development of endometrial carcinomas and could be useful in clinical diagnostics.
Asunto(s)
Carcinoma/genética , Gonadotropina Coriónica/genética , Hiperplasia Endometrial/genética , Neoplasias Endometriales/genética , Hormona Liberadora de Gonadotropina/genética , Receptores LHRH/genética , Receptores de HL/genética , Carcinoma/metabolismo , Gonadotropina Coriónica/metabolismo , Hiperplasia Endometrial/metabolismo , Neoplasias Endometriales/metabolismo , Endometrio/metabolismo , Femenino , Perfilación de la Expresión Génica , Regulación Neoplásica de la Expresión Génica , Hormona Liberadora de Gonadotropina/metabolismo , Humanos , ARN Mensajero/metabolismo , Receptores de HL/metabolismo , Receptores LHRH/metabolismoRESUMEN
Objetivo: O propósito deste trabalho foi avaliar a formação de fenda marginal, através de microscopia eletrônica de varredura, em restaurações de resina composta com quatro técnicas adesivas: Prime & Bond 2.1 (Dentsply) sem condicionamento prévio, Prime & Bond 2.1 com condicionamento convencional com ácido fosfórico, Prime & Bond 2.1 com condicionamento com ácido poliacrílico a 25% e Clearfil SE Bond (Kuraray). Metodologia: Foram utilizados cinco terceiros molares humanos hígidos, nos quais foram preparadas quatro cavidades, sendo que em cada uma foi utilizada uma técnica adesiva. Todas as cavidades foram restauradas com resina composta Z250 (3M/ESPE). Os dentes foram submetidos à termociclagem por 500 ciclos e observados em microscópio eletrônico de varredura para medição da formação de fenda marginal nas paredes gengivais.Resultados: Não houve diferença estatística de fenda marginal entre os grupos experimentais de técnicas adesivas (ANOVA, P>0,05). Conclusão: Nenhuma das técnicas adesivas foi capaz de evitar a formação de fenda marginal; não houve diferença entre as técnicas adesivas empregadas.
Purpose: This study used scanning electron microscopy (SEM) to evaluate the gap formation in composite restorations with four adhesive techniques: Prime & Bond 2.1 (Dentsply) without etching, Prime & Bond 2.1 with conventional etching, Prime & Bond 2.1 with 25% polyacrylic acid conditioning, and Clearfil SE Bond (Kuraray). Methods: Five extracted sound human third molars were used. Four cavities were prepared in each tooth and restored with Z250 (3M/ESPE) composite resin, using each of the four adhesive techniques tested. Teeth were termocycled for 500 cycles and evaluated in SEM to measure gap formation in the gingival walls. Results: No significant difference of marginal gap was found among the four experimental groups of adhesive techniques (ANOVA, P>0.05). Conclusions: None of the tested adhesive techniques was able to avoid marginal gap formation; there was no difference among the adhesive techniques.
Asunto(s)
Humanos , Adaptación Marginal Dental , Resinas Compuestas , Restauración Dental Permanente , Recubrimientos Dentinarios , Microscopía Electrónica de RastreoRESUMEN
OBJECTIVES: The study was undertaken to evaluate selected blood coagulation factors in patients undergoing surgery, due to endometrial cysts and other ovarian benign cysts. MATERIALS AND METHODS: Women involved in our study had not received any previous treatment for endometriosis and they had no history of any prior haemostatic disorders. Blood samples were collected before surgery and investigated for plasminogen, alpha2-antyplasmin, PAI-1 and tPA activity. As a control group, we have analyzed patients with benign gynecological diseases treated in our Department. RESULTS: We have noticed higher mean concentration of plasminogen and alpha2-antyplasmin and lower mean concentration of PAI-1 and tPA activity in our patients in comparison with control group. Obtained results did not show any statistical significance. CONCLUSIONS: Our analysis of haemostatic factors in blood samples did not show coagulation disorders in patients with endometriosis. Maybe there are only local coagulation disorders in endometrial tissue and its surrounding. In our opinion this problem requires further research and taking into consideration other factors.
Asunto(s)
Factores de Coagulación Sanguínea/análisis , Endometriosis/sangre , Quistes Ováricos/sangre , Estudios de Casos y Controles , Quistes/sangre , Femenino , Humanos , Plasminógeno/análisis , Inhibidor 1 de Activador Plasminogénico/sangre , Estudios Retrospectivos , Activador de Tejido Plasminógeno/sangre , Enfermedades Uterinas/sangre , alfa 2-Antiplasmina/análisisRESUMEN
This paper is a comparative analysis of several recent studies on the relationship between Chlamydia trachomatis infection and the development of cervical intraepithelial neoplasia (CIN) and invasive cervical carcinoma. In the pathogenesis of cervical cancer, the role of Human Papillomavirus (HPV) is already well-documented; however, chronic Chlamydia trachomatis infection may have an indirect influence on the development of the disease.