Combined effects of triclosan and PCB153 on the activity of superoxide dismutase and the content of malondialdehyde in zebrafish liver / 预防医学

Objective @#To investigate the combined effects of triclosan（TCS）and PCB153 on the activity of superoxide dismutase（SOD）and the concentration of malondialdehyde（MDA）in zebrafish liver.@*Methods @#Adult zebrafish were exposed to a series of concentrations of TCS,and the mortality in each group was observed and recorded during the acute toxicity test process. The concentrations in subsequent combined exposure experiments were arranged on the basis of the 96 h-LC50. The factorial design was used to determine the concentrations of combined exposure groups between TCS（0,0.125,0.5 μmol/L）and PCB153（0,0.05,0.2 μmol/L）. After 5,10 and 14 days of exposure,the zebrafish livers were dissected and frozen in each group. The potential interactions of these two compounds were analyzed according to the results of the SOD and MDA.@*Results @#The 96 h-LC50 of TCS exposed to adult zebrafish was 2.64 μmol/L（95%CI：2.37-2.89 μmol/L）. After 5 days of exposure,combined exposure to 0.5 μmol/L TCS+0.2 μmol/L PCB153 caused lower liver SOD activities than single exposure groups and the control group（P<0.05）. After 10 days of exposure,combined exposure to 0.125 μmol/L TCS+0.05 μmol/L PCB153,0.5 μmol/L TCS+0.05 μmol/L PCB153 caused lower liver SOD activities than single exposure groups and the control group（P<0.05）. After 14 days of exposure,combined exposure to 0.5 μmol/L TCS+0.05 μmol/L PCB153,0.5 μmol/L TCS+0.2 μmol/L PCB153 caused higher liver SOD activities than single exposure groups and the control group（P<0.05）. There was an interactive effect between TCS and PCB153 on the liver SOD activity in zebrafish（P<0.05）. There was no significant effect of MDA content in each group.@*Conclusion @#Combined exposure to TCS and PCB153 could enhance （inhibit first） the liver SOD activities in zebrafish,and the interaction was synergistic.

Determinación de Bifenilos policlorados (PCB's) en trabajadores de una empresa del sector eléctrico. Barranquilla - Atlántico, 2017 / Determination of polychlorinated biphenyls (PCB's) in workers of a company in the electricity sector. Barranquilla - Atlantic, 2017

Resumen Introducción: Se determinó Bifenilos Policlorados (PCB's) en sangre y pruebas de función orgánica para evaluación de la salud en trabajadores de una empresa del sector eléctrico. Métodos: Fueron seleccionados 61 trabajadores de la empresa Electricaribe S.A de Barranquilla, 30 expuestos al PCB's y 31 no expuestos, mayores de 18 años, sin patología establecida y que firmaron el consentimiento informado. Se analizó: glicemia, perfil lipidico, creatinina, nitrógeno ureico (BUN), bilirrubinas, fosfatasa alcalina, transaminasas pirúvica y oxaloacética, gamma-glutamil transpeptidasa, T3, T4 hormona estimulante de la tiroides (TSH). Para la detección de PCB's, se utilizó un cromatógrafo de gases HP 5890 series II (Hewlett Packard), detector de captura de electrones (EDC) y columna DB-5 (30m x 0.25mm x 0.25μm). Los datos fueron procesados con el software Minitab 15, nivel de confianza 95%. Resultados: Se encontró que el 100% de trabajadores examinados presentaron cifras de PCB's inferiores al valor límite mínimo de detección del método cromatográfico utilizado: 4 μg/L de PCB's, y evaluaciones clínicas negativas para cualquier daño orgánico. Conclusiones: No se encontró diferencia significativa en los resultados obtenidos entre trabajadores expuestos y no expuestos al PCB's.

Abstract Introduction: Polychlorinated Biphenyls (PCB's) in blood and tests of organic function for evaluation of the health in workers of a company of the electrical sector were determined. Methods: We selected 61 company employees Electricaribe S.A. of Barranquilla, 30 exposed to PCB's and 31 unexposed, over 18 years without established pathology and that signed the informed consent. It was analyzed: glycemia, lipid profile, creatinine, blood urea nitrogen (BUN), bilirrubin, alkaline phosphatase, pyruvic and oxaloacetic transaminase, gamma-glutamyl transpeptidase, T3, T4, thyroid stimulating hormone (TSH). For detection of PCB's, a chromatograph HP 5890 series II gas (Hewlett Packard), electron capture detector (EDC) and DB-5 column (30 m x 0.25 mm x 0.25 μm) was used. The data were processed with Minitab 15 software, 95% confidence level. Results: It was found that 100% of workers examined showed PCB's values lower than the minimum limit value of detection of the chromatographic method used: 4 μg/L of PCB's, and negative clinical evaluations for any organic damage. Conclusions: No significant difference in the results between exposed and unexposed to the PCB's workers.

Historical evolution and modern research progress on characteristic processing of porcine cardiac blood processed Salvia miltiorrhiza in Menghe medical school / 中国中药杂志

The porcine cardiac blood processed Salvia miltiorrhiza (PCB Danshen) is the characteristic processing of Menghe medical school and has been inherited for hundreds of years, commonly used in the treatment of brain ischemia-induced agitation, palpitation and phlegm confusing heart. Ancient and modern physicians believe that porcine cardiac blood is a guiding for heart nourishing drugs, which could enhance the effects of Salvia miltiorrhiza by nourishing and soothing the nerves. However, the material basis and processing mechanism of PCB Danshen are still unclear. This paper investigated the historical evolution and modern research of PCB Danshen, including the clinical application, the intention of clinic processing, the processing technology and recent research of PCB Danshen. In addition, the major problems and significance in research and development of PCB Danshen were further thought and prospected, hoping to provide basic data for material basis and processing mechanism of PCB Danshen, and provide effective support for inheriting and carrying forward the characteristic processing technology of Menghe medical school.

Biodegradation of 2,4'-dichlorobiphenyl, a congener of polychlorinated biphenyl, by Pseudomonas isolates GSa and GSb.

Biodegradation of 2,4'-dichlorobiphenyl (2,4 CB), by two isolates of Pseudomonas (GSa and GSb) was compared using GC-MS. Transformer oil polluted soil was used for the isolation of 2,4 CB degrading bacteria. GC-MS analysis of the solvent extracts obtained from Pseudomonas sp. GSa spent culture indicated the presence of Phenol 2,6-bis (1,1-dimethyl)-4-methyl (C15H24O). Further, the enzyme analysis of the cell free extracts showed the presence of 2,4'-dichlorobiphenyl dehalogenase (CBD), 2,4'-dichlorobiphenyl-NADPH-oxido-reductase (2,4 CBOR) and 2,3-dihydro-xybiphenyl-NADPH-oxido-reductase (2,3 DHOR) with specific activity of 6.00, 0.4 and 0.22 μmol/min/mg of protein, suggesting that dechlorination as an important step during 2,4 CB catabolism. Further, the cell free extract of GSb showed only 2,4'-dichlorobiphenyl-NADPH-oxido-reductase (2,4 CBOR) and 2,3-dihydroxybiphenyl-NADPH-oxido-reductase (2,3 DHOR), with specific activity of 0.3 and 0.213 μmol/min/mg of protein, suggesting attack on non-chlorinated aromatic ring of 2,4 CB, releasing chlorinated intermediates which are toxic to the environment. Although, both the isolated bacteria (GSa and GSb) belong to Pseudomonas spp., they exhibited different metabolic potential.

Estudo experimental da exposição ao PCB126 sobre a indução de Diabetes mellitus tipo II / Experimental study of PCB126 exposure on induction of Diabetes mellitus type II

A exposição ambiental aos poluentes orgânicos persistentes tem recebido amplo destaque na literatura recentemente devido à extensa associação entre o desenvolvimento de doenças metabólicas, obesidade e/ou diabetes mellitus, e a presença destes poluentes, principalmente os organoclorados, como as bifenilas policloradas (PCBs), no organismo. Por outro lado, os mecanismos de ação destes poluentes é controverso devido à elevada quantidade de representantes destas classes, gerando diversidade de protocolos de exposição e escassez de estudos experimentais. Por isto, foi objetivo deste trabalho elucidar os mecanismos de ação tóxica do PCB126, nas doses de 0,1; 1 ou 10 µg/kg de massa corpórea, em ratos Wistar machos, durante quinze dias, expostos por instilação intranasal. O procotolo de exposição empregado foi caracterizado e considerado suficiente para causar toxicidade, uma vez que foram observadas alterações no sistema imune, metabolismo e em parâmetros relacionados à gênese do diabetes mellitus. A caracterização da exposição foi determinada pela quantificação da concentração de PCB126 no fígado e pulmão (CG/MS) e pelo aumento da expressão do receptor aril hidrocarboneto (AhR) no rim, fígado, pulmão e tecido adiposo (Western Blot). O efeito imunossupressor do PCB126 foi evidenciado pelo comprometimento da produção de células na medula óssea e, consequentemente, no número de células totais no sangue circulante. Adicionalmente, foi evidenciada a interferência do poluente na via de ativação mediada por receptores acoplados à proteína G (GPCRs), principalmente em neutrófilos, alterando importantes funções destas células, como a expressão de moléculas de adesão, geração de espécies reativas de oxigênio e migração. Entre as alterações metabólicas observadas, destacamos o aumento dos níveis de triglicerídeos e colesterol sérico, aumento da liberação de ácidos graxos livres; aumento da atividade da enzima hepática gama glutamil transferase; aumento da resistência à insulina e aumento da geração de óxido nítrico pelas ilhotas de Langerhans, dados estes, possivelmente relacionados ao comprometimento das células beta (ß) pancreáticas, confirmados pelo aumento da expressão de GLUT4 no tecido adiposo, aumento da concentração de insulina sérica e aumento do estresse oxidativo nas ilhotas de Langerhans. Em conjunto, os dados obtidos destacam importantes alterações causadas pela exposição intranasal ao PCB126, evidenciando a participação do poluente na gênese do diabetes mellitus do tipo II

The environmental exposure to persistent organic pollutants has been widely highlighted in recent literature due to the extensive association between the development of metabolic diseases, obesity and/or diabetes mellitus, and presence of these pollutants, especially organochlorines such as polychlorinated biphenyls (PCBs) in organism. Moreover, the mechanisms of action of these pollutants are controversial due to the high number of PCBs congeners, diversity of exposure protocols and lack of experimental studies. Therefore, the aim of this study was to elucidate the mechanisms of PCB126's toxic action at doses of 0.1; 1 or 10 µg/kg body weight in male Wistar rats exposed by intranasal instillation for 15 days. The established exposure procotol was characterized and considered sufficient to cause toxicity since changes were observed in the immune system, metabolism and in parameters related to the pathogenesis of diabetes mellitus. Characterization of exposure was determined by quantifying the concentration of PCB126 in liver and lung (GC-MS) and by the increased expression of aryl hydrocarbon receptor (AhR) in kidney, liver, lung, and adipose tissue (Western blot). The immunosuppressive effect of PCB126 was evidenced by impairment of cell production in the bone marrow and thus the total number of cells in the circulation. In addition, the interference of the pollutant in the activation pathway mediated by G-protein coupled receptors (GPCRs), in particular in neutrophils, was observed by changing important functions of these cells such as the expression of adhesion molecules, reactive oxygen species generation, and migration. Among the metabolic changes observed, we highlight the increased levels of triglycerides and serum cholesterol, increased release of free fatty acids; increased gamma glutamyl transferase hepatic enzyme activity; increased insulin resistance and increased generation of nitric oxide by the islets of Langerhans, these data possibly related to the impairment of beta cells (ß) pancreatic function, suggested by the increased expression of GLUT4 in adipose tissue, increased serum insulin concentration and increased oxidative stress in the islets of Langerhans. Altogether, these results highlight important changes caused by intranasal exposure to PCB126, suggesting participation of the pollutant in the genesis of diabetes mellitus type II

The effect of the structure of polychlorinated biphenyls on their hydroxylation, oxidation, and glutathionyl conjugation reactions / 生物医学与环境科学（英文）

<p><b>OBJECTIVE</b>To compare the nature of the metabolites formed from the phase I metabolism (hydroxylation and oxidation) and phase II metabolism (glutathionyl conjugation) of PCBs that have different chlorine substitution patterns. To discuss the structure-activity relationships and metabolic mechanisms of PCBs.</p><p><b>METHODS</b>4-Cl-biphenyl (PCB3), 4,4'-Cl-biphenyl (PCB15), 3,4,3',4'-Cl-biphenyl (PCB77) were used for in vitro metabolic study. LC/MS and UV-Vis studies were performed for metabolites identification.</p><p><b>RESULTS</b>The cytochrome P-450 catalyzed hydroxylation rate decreased as the number of chlorine substitutions increased. In this reaction, PCB3 was fully metabolized, approximately half of the PCB15 was metabolized and PCB77 was not metabolized at all. The oxidation rate of PCB15-HQ was higher than that of PCB3-HQ under various oxidation conditions. The LC/MS and UV-Vis data suggest that in the conjugation reaction of PCB15-Q and GSH, the Michael addition reaction occurs preferentially over the displacement reaction.</p><p><b>CONCLUSION</b>The metabolic profiles of polychlorinated biphenyls (PCBs) are dramatically affected by chlorine substitution patterns. It is suggested that the metabolic profiles of PCBs are related to their chlorine substitution patterns, which may have implications for the toxicity of PCB exposure.</p>

Using systematic reviews and meta-analyses to support regulatory decision making for neurotoxicants: lessons learned from a case study of PCBs / Utilizando revisões sistemáticas e meta-análise de apoio às decisões regulatórias para neurotóxicos: lições de um estudo de caso dos PCBs

We examined prospective cohort studies evaluating the relation between prenatal and neonatal exposure to polychlorinated biphenyls (PCBs) and neurodevelopment in children to assess the feasibility of conducting a meta-analysis to support decision making. We described studies in terms of exposure and end point categorization, statistical analysis, and reporting of results. We used this evaluation to assess the feasibility of grouping studies into reasonably uniform categories. The most consistently used tests included Brazelton's Neonatal Behavioral Assessment Scale, the neurologic optimality score in the neonatal period, the Bayley Scales of Infant Development at 5-8months of age, and the McCarthy Scales of Children's Abilities in 5-year-olds. Despite administering the same tests at similar ages, the studies were too dissimilar to allow a meaningful quantitative examination of outcomes across cohorts. These analyses indicate that our ability to conduct weight-of-evidence assessments of the epidemiologic literature on neurotoxicants may be limited, even in the presence of multiple studies, if the available study methods, data analysis, and reporting lack comparability.

Foram examinados estudos de grupo que avaliaram a relação entre a exposição pré-natal e neonatal aos bifenilos policlorados (PCB) e o desenvolvimento neuropsicomotor em crianças a fim de avaliar a viabilidade da realização de uma meta-análise para suporte à tomada de decisão. Nós descrevemos os estudos em termos de exposição, categorizações, análise estatística e elaboração de relatórios de resultados. Nós utilizamos esta avaliação para verificar a viabilidade de agrupar os estudos em categorias razoavelmente uniformes. Os testes mais utilizados foram Brazelton Neonatal Behavioral Assessment Scale, a pontuação de otimalidade neurológica no período neonatal, as Escalas Bayley de Desenvolvimento Infantil de 5 a 8 meses de idade, e as Escalas McCarthy de habilidades das crianças em 5 anos de idade. Apesar de administrar os mesmos testes com idades semelhantes, os estudos foram muito diferentes para permitir uma análise quantitativa significativa dos resultados entre grupos. Estas análises indicam que a nossa capacidade de realizar avaliações da literatura epidemiológica sobre neurotóxicos pode ser limitada - mesmo na presença de vários estudos - se não existe nenhuma forma de comparação com os métodos de estudo disponíveis e análise dos dados.

José Carlos Mariátegui e o Brasil

Este artigo discute especialmente a recepção da obra do jornalista e teórico marxista peruano José Carlos Mariátegui no Brasil, sua influência no meio acadêmico e político, e as diferentes leituras e abordagens de suas ideias no país, do final dos anos 1920 até a atualidade, assim como também mostra as tentativas de aproximação de JCM com artistas e intelectuais brasileiros.

This article discusses primarily the reception of the work of the Peruvian journalist and Marxist theoretician José Carlos Mariátegui in Brazil, his influence in the academic and political milieu, and the different readings and approaches to his ideas in this country, from the late 1920's to the present day; it shows, as well, JCM's efforts to establish links and relations with Brazilian artists and intellectuals.

Los contaminantes ambientales bifenilos policlorinados (PCB) y sus efectos sobre el Sistema Nervioso y la salud / The polychlorinated biphenyls (PCBS) environmental pollutants and their effects on the Nervous System and health

Environmental pollution is a world-wide issue which is a matter for concern among the international community. Great industrialized cities are the most polluted and Mexico City is among them. However, pollution affects places which are far away from contaminated urban areas, thus damaging eco-systems. Environmental pollution is responsible for an alarming and increasing list of illnesses in humans, animals and plants. This has generated an international interest in this problem. From the 187 chemical agents considered toxic for living organisms, the Inter-Government Committee for the Negotiation of Persistent Organic Pollutants (Pops) has catalogued 12 as the most hazardous for life. Among them are the so-called polychlorinated biphenyls (PCBs). PCBs are a family of 209 structurally chlorinated compounds made up of chlorine, carbon and hydrogen. These compounds are chemically and thermally stable, insoluble in water, non-flammable, electrically resistant, with low volatility at normal temperatures, and bio-degradable only at high temperatures (1200°C). One of their main disadvantages is that they are subject to a process of bioaccumulation where their concentration increases along the food chain. Their physical properties make them widely used in industry, mainly in the electrical and building areas. Not long after PCBs were manufactured, it was determined that food for human intake such as milk, fish and eggs, to mention just a few, presented higher PCBs concentrations than those allowed by the Organism for US Environmental Protection (0.0005mg/l). It has been demonstrated that PCBs can cause damage to the endocrine, immunologic and Nervous Systems, among others. The underlying mechanism of action of these compounds is through the activation of the aril hydrocarbon receptor (AhR), a ligand-dependent cytosolic transcription factor. PCBs act like ligands and, given their lipophilic properties, enter cells by passive diffusion. Two co-chaperone proteins are bound to AhR to form an oligomer which dissociates when binding to a PCB. After ligand binding, a heterodimer is formed which translocates into the nucleus and links to specific DNA regions; this in turn regulates the transcription velocity of specific genes and produces genetic alterations that modify processes and functions in the cell. PCBs belong in the group of chemicals considered endocrine disruptors. Damage caused by these compounds can be irreversible. In the endocrine system they interfere with the production and regulation of steroid and thyroid hormones, acting as agonists or antagonists of hormone receptors. They impair endocrine metabolic pathways, such as those of thyroid hormones (T3 and T4), and inhibit carrier proteins such as transthyretin. Contaminants that harm the endocrine system also affect the reproductive function and disrupt various aspects of sexuality. In males, PCBs inhibit the synthesis of testosterone, alter masculinity, reduce sperm motility and the capacity of binding and penetrating the ovule, induce changes in the shape of the penis as well as its size, retard or inhibit testicle descent, and can generate testicular cancer. In females, they can cause early menarche (first menstruation), enhanced duration of menstrual bleeding, urogenital malformations, endometriosis, spontaneous abortion, fetal death, premature delivery and low-weight in offspring. Our group, as well as other research groups, has encountered that PCB administration to gestating rats causes an increment in offspring mortality, fetal miscarriages, low bodily weight of the offspring and a reduction in the number of males per litter. The immunological system is sensitive to chemicals such as PCBs which originate an immunological response; they act as immunotoxins that cause thymus atrophy, affect innate immunity, compromise host resistance and immunity mediated by B and T cells, as well as humoral immunity. PCBs and their metabolites are carcinogenic and act as general cancer promoters by enhancing the effects of other substances through the generation of oxygen reactive compounds that can induce DNA oxidative damage. Chronic PCB exposure can cause chromosomal aberrations; these compounds have been related to all types of cancer: mammary gland, liver, biliary tract, gastrointestinal, skin (especially malignant melanomas), lung, pancreas and brain. There is evidence that organisms are more vulnerable to PCB exposure during the early embryonic stages. These compounds can cross the placenta and affect the fetus; when they are present in human milk they keep the offspring under high PCB levels thus altering development. In addition, they can contribute to the interruption of growth and development of brain, organs and tissues. As a result, malfunctions or miscarriage occur. PCBs are involved in the neurodegeneration process since they affect dopaminergic neurons in caudate nucleus, ventral tegmental area and substantia nigra. These compounds disrupt neuronal mechanisms such as vesicular transport and dopamine release which lead to cellular death similar to that described for diseases such as Parkinson's. Perinatal exposure to PCBs is associated with neurodevelopmental deficiencies of infants which consist of dysfunctions at the neuropsychological level such as in verbal learning (syllables, words and concepts), performance functions, changes in attention and psychomotor development. Acute or chronic exposure to PCBs is associated with cephalea, insomnia, nervousness, irritability, depression and anxiety; these symptoms in turn modify behavior. At the neurophysiological level, these contaminants impair excitatory and inhibitory synaptic transmission in the hippocampus, inhibit long-term potentiation and synaptic plasticity, alter some mechanisms of cell signaling (GABAergic pathway), and deteriorate learning and memory. Recently, these compounds have been related to cognitive alterations. Our group demonstrated that the administration of PCB-77 and Aroclor 1254 during gestation inhibits the enzymatic activity of nitric oxide synthase (NOS) in 10-day postnatal pups. These rats presented degenerative morphological neuronal changes such as shrinking, picnosis, loss of neurites, neuronal death and decrease in the number of nitrergic neurons in the paraventricular and supraoptic hypothalamic nuclei. We also reported that in these nuclei a decrease in immunoreactivity to vasopressin and neuronal NOS is observed. The evidence in PCB studies is conclusive. The exposure to these environmental toxins interferes with the functioning of various organs and systems such as the endocrine and Nervous Systems, not only in humans but also in animals. These contaminants pose a risk factor for a wide number of neurodegenerative alterations.

La contaminación ambiental es un grave problema mundial que actualmente preocupa a la comunidad internacional. Las grandes ciudades industrializadas, como la de México, son las más contaminadas. Sin embargo, la contaminación llega hasta zonas alejadas de donde se produce y afecta los ecosistemas. La contaminación es responsable de una alarmante y creciente lista de enfermedades en el hombre, los animales y las plantas. Los bifenilos policlorados (PCB) se catalogaron dentro de los 12 contaminantes orgánicos más tóxicos para los organismos vivos. Sus propiedades físicas hicieron que se usaran ampliamente en la industria. No son biodegradables y se acumulan en el ambiente, se transfieren dentro de la cadena alimenticia y tienden a concentrarse más al final de ésta, por lo que en los alimentos se determinaron concentraciones que sobrepasaban los límites establecidos por el Organismo de Protección del Ambiente de los Estados Unidos. Se demostró que los PCB afectan la función de los sistemas endocrino, inmunológico y nervioso, entre otros. El mecanismo de acción descrito para los PCB, es por medio de la activación del receptor aril hidrocarburo, un factor de transcripción citosólico dependiente de ligando. Los PCB actúan como ligandos y son lipofílicos, por lo que entran a la célula y llegan al núcleo para unirse al ADN, lo cual altera la trascripción de genes específicos y provoca alteraciones genéticas que conducen a cambios en los procesos y funciones celulares. Los PCB interfieren con la producción y regulación de las hormonas esteroides y tiroideas al actuar como antagonistas o agonistas de los receptores hormonales. Afectan la función reproductora y alteran diferentes aspectos de la sexualidad. Como otros grupos de investigación, el nuestro ha observado que la administración de PCB a ratas gestantes causa un incremento de la mortalidad de las crías, pérdida fetal, peso corporal bajo y una reducción en el número de machos por camada. Los PCB actúan como inmunotoxinas que causan la atrofia del timo y afectan la respuesta inmune. Los PCB y sus metabolitos son carcinogénicos debido a la generación de especies reactivas de oxígeno que pueden producir daño oxidativo al ADN, provocar aberraciones cromosómicas y generar cáncer de mama, hígado, tracto biliar, gastrointestinal, cerebral, etc. Los organismos son más vulnerables a la exposición de los PCB durante las etapas tempranas del desarrollo embrionario. Los PCB atraviesan la placenta y llegan al feto, permanecen en la leche materna y mantienen niveles altos en las crías. Los PCB afectan así el desarrollo del Sistema Nervioso, los órganos y los tejidos, y pueden llevar a la pérdida fetal. También se asocian a deficiencias en el neurodesarrollo del niño y a alteraciones neuropsicológicas en la atención, el aprendizaje y el desarrollo psicomotor. La exposición aguda o crónica a los PCB se asocia con cefalea, insomnio, nerviosismo, irritabilidad, depresión y ansiedad. Los PCB participan en el proceso de neurodegeneración al afectar el sistema dopaminérgico. En el nivel neurofisiológico, afectan la transmisión sináptica excitatoria e inhibitoria hipocampal; inhiben la potenciación a largo plazo y la plasticidad sináptica; alteran mecanismos de señalización celular como el GABAérgico, en el aprendizaje y la memoria, y producen alteraciones cognoscitivas. Nuestro grupo demostró que la administración de los PCB durante la gestación inhibe la actividad de la enzima sintasa del óxido nítrico y provoca cambios neuronales morfológicos degenerativos en los núcleos paraventricular y supraóptico hipotalámicos. Las evidencias de los estudios realizados con los PCB son concluyentes en cuanto a que la exposición a estos tóxicos ambientales interfiere con el funcionamiento de diferentes órganos y sistemas y a que son un factor de riesgo para un amplio número de alteraciones neurodegenerativas. Actualmente, las poblaciones están expuestas a concentraciones que exceden los niveles límite tolerables recomendados por la Organización Mundial de la Salud. Nuestro grupo está analizando las alteraciones de estos contaminantes en el nivel neuroendocrino y en algunos aspectos del aprendizaje y la memoria. Dada la relevancia de los efectos de los PCB en la salud y de la falta en México de una valoración de los niveles de los PCB existentes en personas y alimentos, es importante que las instituciones de salud fomenten y apoyen las investigaciones en esta área.

Biodegradación ee compuestos orgánicospersistenes (cop): i. el caso de los biffenilospoliclorados (pbb) / Biodegradation Of Persistent Organic Pollutants (POPs): I The Case Of Polychlorinated Biphenyls (PCB)

Los contaminantes orgánicos persistentes poseen propiedades tóxicas, son resistentes a la degradación, se bioacumulan y son transportados por el aire, el agua y las especies migratorias a través de las fronteras internacionales; en consecuencia se depositan lejos del lugar de su liberación, acumulándose en ecosistemas terrestres y acuáticos. Para atender a esta problemática a nivel mundial se firmó el 23 de mayo de 2001 el Convenio de Estocolmo. Aunque por ahora los COP estan prohibidos en la mayoria de los países, todavía existen en el mundo muchos sitios contaminados con estas sustancias. La remediación de sitios que presentan contaminantes orgánicos persistentes requiere consideraciones distintas a las contempladas en la recupe-ración por contaminación de hidrocarburos. El siguiente texto revisa la literatura sobre la biodegradación anaeróbica y aeróbica de los bifeniles policlorados (PCB) y las posibles estrategias para estimular dicha biodegradación. La degradación de los demás COP será descritas en textos adicionales.

Persistent organic pollutants are chemicals that are toxic to humans and wildlife, remain intact in the environment for long periods, accumulate in living organisms and can become widely distributed geographically by air, water or migrating species. As a result, these contaminants have been found all over the world including in places, such as the Polar Regions, which are very far from their application site. The Stockholm Convention was signed in 23/5/01 in order to cope with this international environmental problem. Although POPs were banned by most countries, there are still a lot of sites contaminated with these substances. The remediation of these sites is problematic and requires distinct considerations from those which are established for hydrocarbon remediation. This manuscript reviews the literature about anaerobic and aerobic biodegradation of polychlorinated biphenyls (PCB) and possible strategies to stimulate these processes. The degradation of the other POPs would be reviewed in additional texts.

Effects of PCB Congeners in Rodent Neuronal Cells in Culture

We attempted to analyze the mechanism of polychlorinated biphenyl (PCB) -induced neurotoxicity and identify the target molecules in the neuronal cells for PCBs. Since the developing neuron is particularly sensitive to PCB-induced neurotoxicity, we isolated cerebellar granule cells derived from 7-day old Sprague Dawley (SD) rats and grew cells in culture for additional 7 days to mimic PND-14 conditions. Only non-coplanar PCBs at a high dose showed a significant increase of total protein kinase C (PKC) activity at phobol 12, 13-dibutyrate ([3H]PDBu) binding assay, indicating that non-coplanar PCBs are more neuroactive than coplanar PCBs in neuronal cells. PKC isozymes were immunoblotted with the selected monoclonal antibodies. PKC-alpha, delta, and epsilon were activated with non-coplanar PCB exposure. Receptor for activated C kinase-1 (RACK-1), anchoring protein for activated PKC, was more induced with exposure to coplanar PCBs than non-coplanar PCBs. Reverse transcription PCR (RT-PCR) analysis showed induction of neurogranin (RC-3) and growth associated protein-43 (GAP-43) mRNA with non-coplanar PCBs. The results indicate that these factors may be useful biomarkers for differentiating non-coplanar PCBs from coplanar PCBs. The present study demonstrated that non-coplanar PCBs are more neuroactive congeners than coplanar PCBs.

Clinical Experience of Anterior Cervical Interbody Fusion with the PCB System

OBJECTIVE: The purpose of the study was to evaluate the clinical and radiological results after discectomy and Lubboc bone graft in the surgical management of the cervical diseases with a new titanium interbody implant and integrated screw fixation(PCB) by anterior approach. METHODS: The authors retrospectively analyzed 28 cases of anterior cervical fusion with PCB system and Lubboc bone(xeno graft) from september 1998 to december 2000. Twenty-eight patients with cervical diseases underwent decompression cervical lesion and followed from 5 to 27 months with a mean follow-up of 14 months. There patients were evaluated with clinically and radiologically at immediate postoperative period and at 3, 6, 9, and 12 months. RESULT: The authors investigated the pre- and postoperative intervertebral disc space, clinical outcomes, radiography fusion rate, and Cobb angle in the fixed segments by anterior approach. The lordotic angles and height of disc space were increased after the operation. The clinical outcome of patients follow-up was good or excellent result based on Odom's criteria with improvement of clinical symptom in about 92.9% of the cervical diseases. Two patients showed loosening of the lower and upper cervical screw of PCB instruments, and two patients showed swallowing difficulty and wound infection. CONCLUSION: The PCB system is a new implant for anterior cervical interbody fusion in the degenerative cervical disease and disc herniations. It provides immediate stability and segment distraction. The results of this study indicate that the PCB system is safe, easy handling of hardware, less complications, high fusion rate, and has provide the keeping the intervertebral disc space height and lordotic angles.

PCB Instrumentation with Lubboc Bone in Anterior Cervical Interbody Fusion

OBJECTIVE: PCB cervical instrument is a newly introduced fusion device which comprises cervical plate, cage (spacer) and screw system. It is developed to enhance fusion rate and stability, as well as to reduce complications related to hardware failure. We investigated the efficacy of clinical and radiological results of PCB instrument and Lubboc bone. METHODS: From August, 1998 to October, 1999, authors performed 54 cases of anterior cervical interbody fusion with PCB instrument and Lubboc bone. Retrospective analysis was undertaken based on clinical and radiological findings. Clinical improvement was evaluated according to Odom's criteria. Cervical plain films and tomography were taken every 2 months to evaluate the degree of interbody fusion and disc height changes. RESULTS: Bone fusion was observed in 36 cases(90%) over 6 months after operation, and during which time there was no significant interval change. There were 3 cases of hardware dislodgement. Disc height was increased significantly and preserved in all cases. Clinical outcome over good degree was seen more than 94% of patients. CONCLUSION: Longer follow-up period and comparative studies to similar instrument appear to be necessary, but this instrumentation system has shown high fusion rate and fewer adverse effects in our series. We believe this system might be indicated for the treatment of cervical trauma and degenerative disease in selective cases.

Continuous Exposure of Lactating Rat Mothers to Polychlorinated Biphenyls (PCBs) Increases Testis Volume, Sperm Production and Sertoli Cell Numbers in Adult Male Offspring / 체질인류학회지

Despite the possible consequences of maternal ingestion of polychlorinated biphenyls (PCBs) on future generation, information in limited on how/whether maternal PCB exposure affects testis of the adult male offspring. Therefore, we conducted two experiments to investigate the effects of intermittent and continuous of lactating rats to low and high doses of Aroclor 1242 (a PCB congener) on volume density of seminiferous tubules and interstitium, testis volume, sperm production/day and the total number of Sertoli cells per testis in adult male offspring. In experiment I, 3 groups of lactating Sprague Dawley rats received daily subcutaneous injections of 0.1 ml of corn oil, low dose (8microgram) and high dose (80microgram) of Aroclor 1242 in corn oil respectively, from parturition to weaning of pups at 21 days. In experiment II, 3 groups of lactating rats received 2 subcutaneous injections per week of 0.1 ml corn oil, low and high doses of Aroclor respectively, as in experiment I. Pups in all groups were weaned at day 21 and were raised on a normal diet until sacrificed at 90 days to evaluate volume density of seminiferous tubules and interstitium, testis volume, sperm production/day and the total number of Sertoli cells per testis. Volume density of seminiferous tubules and interstitium per testis was determined by point counting method. Testis volume and sperm production/day was measured by routine techniques. The total number of Sertoli cells per testis was determined by morphometry(disector method). In experiment I and II, the volume density of seminiferous tubules and interstitium per testis was equal in control and treated testes. In experiment I (continuous exposure), the testis volume was increased by 14.8% (low dose)~16.5% (high dose), and sperm production/day and Sertoli cell numbers were increased 20.4~25%, and 32.6~39.4%, respectively. In experiment II (intermittent exposure), testis volume, sperm production/day and the total number of Sertoli cells per testis were not significantly different (p>0.05) in PCB-exposed rats (both low and high doses) compared to controls. It is clear that continuous exposure, but not intermittent exposure of male rats to Aroclor during the neonatalprepubertal period causes detrimental effects on the testis in adult male offspring. These results emphasize the susceptibility of the developing testis to environmental factors during the crucial neonatal period.

Anterior Cervical Fusion with the PCB Instrumentation (Cervical Plate Cage System) in Degenerative Cervical Disease

OBJECTIVE: The anterior interbody fusion for cervical spine disorder may not provide adequate immediate stabilization, whereas anterior cervical spine plating has overcome this main disadvantage. Recently, several types of hardware were introduced and the complications related to these were also reported. In case of degenerative cervical spine disorders, the adequate intervertebral disc space height and lordotic curvature are the major factors for preventing recurrence of symptoms. So we used the PCB instrumentation(cervical plate cage system) for these purpose. MATERIAL AND METHOD: From April 1998 to October 1998, 16 patients with degenerative cervical spine disorders who had radiculopathy or myelopathy were underwent anterior cervical spine fusion with the PCB instrumentation(cervical plate cage system). Single level fusion was accomplished in 8 patients and two level fusion in 8. The mean follow-up period was 4 month. RESULT: All patients show some recovery at discharge. There were no hardware problems. The intervertebral disc space height and lordotic curvature were not changed during follow up. CONCLUSION: These finding suggest that PCB instrumentation can be considered to be one of the useful hardwares for anterior cervical spine fusion in degenerative cervical spine disorders.

Study on the Demonstration of Enteroviruses from Cerebrospinal Fluid of Adult Patients with Aseptic Meningitis / 대한내과학회지

BACKGROUND: The enteroviruses are the most common etiologic agent of aseptic meningitis in adults and children. The incidence of enteroviral meningitis in childhood meningitis is up to 80%, but in adults is not known, worldwidely. In Korea, where tuberculosis is endemic, the rapid and accurate diagnostic method for enteroviral meningitis is required especially because early differential diagnosis of viral meningitis from tuberculous meningitis is very important. The aims of this study were the demonstration of enteroviruses from cerebrospinal fluid (CSF) of adult patients with aseptic meningitis by PCR/Southern hybridization and the verification of the usefulness of PCR/southern hybridization as a rapid diagnostic tool. METHODS: From July 1992 to June 1995, total 34 CSF samples (10 from children, 24 from adults) of patients with aseptic meningitis were studied. As a control group, 15 patients with tuberculous meningitis and 15 patients with bacterial meningitis were studied. Viral RNA was extracted from CSF, reverse transcriptied into cDNA and amplified. The PCR products were Southern hybridizied with enteroviruses-specific digoxigenin-labelled probe. RESULTS: 16/24(66.7%) samples of adult patients with aseptic meningitis were positive for enteroviruses, while in child patients with aseptic meningitis, 9/10(90%) samples were positive. And in one patient, PCR was positive from asymptomatic, onset-7th day CSF sample. CONCLUSION: Enteroviruses were the most common causative organisms of adult aseptic meningitis in Korea. And, this study showed the usefulness of PCR/Southern hybridization of enteroviruses from CSF for etiologic diagnosis of adult aseptic meningitis in subclinical, asymptomatic period.

Circuit analysis and PCB adjusting of R-500 X-ray machine / 医疗卫生装备

Abstract PCB faults on X-ray machine occur frequently in our hospital due to humid climate, which lead to many malfunctions such as potentiometer failure, blank screen, lacking KV display, unavailable parameter choosing and disappearing of Er1～Er7 fault code. These malfunctions could be diagnosed and repaired quickly based on analyzing the status of the machine's workflow indicator lights, as well as studying circuit and function principle of the equipment.

A REPORT ON 16 CASES OF CERVICAL SPONDYLOSIS TREATED WITH THE USE OF PCB / 解放军医学杂志

An evaluation of 16 patients with cervical spondylosis undergoing PCB (a new anterior cervical instrumental system combining an intradiscal cage with an integrated plate,PCB) is presented. Four patients underwent surgery for cervical myelopathy and 12 for cervical radiculopathy.There were 11 males and 5 females.The average age was 46 years (ranging from 31～67 years).The time of follow up was 3～16 months after operation.Fixation at one level was performed in 12 patients,and at two levels in 4. The results revealed that the technique was easy to learn and implement,without intraoperative complications.After surgery no screw backout or device failure was identified.Symptoms improved significantly in 14 patients.Complications in donor site were rare. An external collar support was unnecessary after operation.