Ecological Drawbacks of Nanomaterials Produced on an Industrial Scale: Collateral Effect on Human and Environmental Health.

Currently, hundreds of different nanomaterials with a broad application in products that make daily lives a little bit easier, in every aspect, are being produced on an industrial scale at thousands of tons per year. However, several scientists, researchers, politics, and ordinary citizens have stated their concern regarding the life cycle, collateral effects, and final disposal of these cutting-edge materials. This review summarizes, describes, and discusses all manuscripts published in the Journal Citation Reports during the last 10 years, which studied the toxicity or the effects of nanomaterials on human and environmental health. It was observed that 23.62% of the manuscripts analyzed found no ecological or human risks; 54.39% showed that several nanomaterials have toxicological effects on the ecosystems, human, or environmental health. In comparison, only 21.97% stated the nanomaterials had a beneficial impact on those. Although only 54.39% of the manuscripts reported unfavorable effects of nanomaterials on ecosystems, human, or environmental health, it is relevant because the potential damage is invaluable. Therefore, it is imperative to make toxicological studies of nanomaterials with holistic focus under strictly controlled real conditions before their commercialization, to deliver to the market only innocuous and environmentally friendly products.

Effect of Parenteral Antioxidant Supplementation During the Dry Period on Postpartum Glucose Tolerance in Dairy Cows.

BACKGROUND: Exacerbated postparturient insulin resistance (IR) has been associated with several pathologic conditions in dairy cattle. Oxidative stress (OS) plays a causative role in IR in humans, and an association, but not direct relationship, between OS and IR recently has been reported in transition dairy cattle. HYPOTHESIS: Supplementation with antioxidants shortly before calving improves glucose tolerance after parturition in dairy cattle. ANIMALS: Ten late-pregnant Holstein cows entering their 2nd to 5th lactation. METHODS: Randomized placebo-controlled trial: 15 ± 2 days before expected calving, the treatment group received an injection of DL-alpha-tocopheryl acetate at a dosage of 6 mg/kg body weight (BW) and 0.06 mg/kg BW of sodium selenite, and the control group was injected with isotonic saline. During the first week after calving, both groups underwent glucose tolerance testing (0.25 g glucose/kg BW). Commercial assays were used to quantify the concentrations of glucose, insulin, nonesterified fatty acids (NEFA), beta-hydroxybutyrate, and markers of redox status in blood. Data were analyzed using the Mann-Whitney U-test (α = 0.05). RESULTS: Supplemented cows showed a lower risk for OS, as reflected by a lower OS index (P = .036), different areas under the curve for the concentrations of glucose (P < .01), insulin (P = .043), and NEFA (P = .041), more rapid elimination rates (P = .080, <.01 and .047 respectively), and shorter half-lives (P = .040, <.01 and .032) of these metabolites. CONCLUSIONS AND CLINICAL IMPORTANCE: Supplementation with antioxidants before calving resulted in greater insulin sensitivity after calving, thereby suggesting the role of OS in the development of IR in cattle and the potential benefits of antioxidant supplementation in minimizing the consequences of negative energy balance.

The importance of the oxidative status of dairy cattle in the periparturient period: revisiting antioxidant supplementation.

Dairy cows are especially vulnerable to health disorders during the transition period, when they shift from late pregnancy to the onset of lactation. Diseases at this stage affect not only the animals' well-being, but also cause a major economic impact in dairy farms, because apart from treatment costs, affected cows will not reach their peak milk-producing capacity. The overproduction of reactive oxygen species (ROS) leads to oxidative stress, which has been identified as an underlying factor of dysfunctional inflammatory responses. Supplementation with vitamins and trace elements attempts to minimize the harmful consequences of excessive ROS production, thereby trying to improve animals' health status and to reduce disease incidence. However, results regarding the effects of supplementing antioxidants on dairy cows' health and performance have been inconsistent, because in most cases, the antioxidant potential of the animals was not assessed beforehand and the nutritional strategy planned accordingly. Therefore, reviewing the physiological and harmful effects of ROS production, along with the different options available for assessing the redox balance in dairy cattle and some of the key findings of different supplementation trials, could bring one step forward the on-farm application of determinations of oxidative status for establishing nutritional strategies early enough in the dry period that could improve transition cow health.

ErbB receptors and PKC regulate PC12 neuronal-like differentiation and sodium current elicitation.

Excitability, neurite outgrowth and their specification are very important features in the establishment of neuronal differentiation. We have studied a conditioned medium (CM) from sciatic nerve which is able to induce a neuronal-like differentiation of PC12 cells. Previously, we have demonstrated that supplementing this CM with a generic inhibitor (k252a), which mainly inhibits tropomyosin-related kinase receptors (Trk receptors) and protein kinase C (PKC), caused neurite elongation, sodium current induction and axon development. In the present work, we are showing that the enhancement of neurite length and induction of sodium currents induced by CM+k252a were prevented by ErbB receptor inhibition. Additionally, we demonstrated that specific inhibition of PKC produced a similar effect to that exerted by k252a in CM-treated cells, specifically by increasing the percentage of differentiated cells with long neurites and inducing sodium currents. Moreover, CM changed the mRNA levels for ErbB2 and ErbB3 increasing them 6- and 36-folds respectively compared to their control. The inclusion of k252a with CM changed the ErbB1, ErbB2 and ErbB3 mRNA proportions increasing those eight-, seven- and fivefolds respectively. From this point, it is clear that appropriate ErbB receptor levels and PKC inhibition are necessary to enhance the effect of the CM in inducing the neuronal-like differentiation of PC12 cells. In summary, we demonstrated the involvement of ErbB receptors in the regulation of neurite elongation and sodium current induction in PC12 cells and propose that these processes could be initiated by ErbB receptors followed by a fine regulation of PKC signaling. These findings might implicate a novel interplay between ErbB receptors and PKC in the regulation of these molecular mechanisms.

Effect of moderate Cu supplementation on serum metabolites, enzymes and redox state in feedlot calves.

The aim of this investigation was to evaluate whether, in the nutritional management of commercial feedlots, copper (Cu) supplementation is justified to maintain the physiological requirements. This study compared beef calves fed concentrates with an average Cu basal content of 5 and 8 mg/kg in growing and finishing periods (10 animals) or supplemented with 15 mg/kg for each phase (20 animals) as regards production indices, metabolic parameters [glucose, nonesterified fatty acids (NEFA), cholesterol, serum urea nitrogen (SUN), creatinine, total serum protein (TSP), albumin, aspartate transaminase (AST) and γ-glutamyl transferase (GGT)] and markers of oxidative stress (reactive oxygen species (ROS) and serum antioxidant capacity (SAC)). Data were recorded at ages 12, 24 and 36 weeks. In general, Cu supplementation was neither detrimental nor beneficial for animal health and performance, and the levels of the measured metabolites and enzymes were within their normal ranges stated for feedlot with the same management during the whole study. However, in keeping with reported higher hepatic Cu levels at slaughter, animals on supplemented feed had higher GGT activities at the end of the finishing stage, although the difference was not statistically significant. On the other hand, lower SAC levels at the end of the growing period in the supplemented group suggest the possibility of a positive effect of Cu supplementation on redox state. Further research is necessary to clarify the potential role of Cu in limiting the ROS production associated with fattening diets, and to evaluate the hepatobiliary consequences of supplementation, including hepatic Cu accumulation.

Wine industry residues extracts as natural antioxidants in raw and cooked chicken meat during frozen storage.

The effect of Isabel (IGE) and Niagara (NGE) grape seed and peel extracts on lipid oxidation, instrumental colour, pH and sensory properties of raw and cooked processed chicken meat stored at -18°C for nine months was evaluated. The pH of raw and cooked samples was not affected by the addition of grape extracts. IGE and NGE were effective in inhibiting the lipid oxidation of raw and cooked chicken meat, with results comparable to synthetic antioxidants. The extracts caused alterations in colour, as evidenced by the instrumental (darkening and lower intensity of red and yellow colour) and sensory results of cooked samples. In the sensory evaluation of odour and flavour, IGE produced satisfactory results, which did not differ from synthetic antioxidants. These findings suggest that the IGE and NGE are effective in retarding lipid oxidation of raw and cooked chicken meat during frozen storage.

Consejería en vida sana y cambio de conductas en escolares obesos: intervención controlada en madres/cuidadoras / Counseling on healthy lifestyles and behavioral change in obese school children: controlled intervention in mothers/caretakers

Obesity is the main nutritional problem among Chilean children. Behavioral changes through the stage of change model have been proposed as allow cost prevention alternative that has greater impact than the informative model. The purpose of this study was to evaluate the effect of counseling on healthy lifestyles on the behavioral changes of obese children 6 to 9 years of age. A quasi-experimental pilot study including mothers caretakers (N=50) of obese children from public schools was carried out. The intervention consisted in three home-based counseling sessions to the mothers caretakers during a 16-week period. The main results indicated that counseling contributed to decreased daily television time and improved the nutritional quality of the foods brought from home by children from the intervention group compared to children from the control group. Counseling is an effective prevention strategy whose effects need to be confirmed in a randomized study including a larger sample.

La obesidad es el principal problema nutricional de la población infantil en Chile. La modificación de conductas a través del modelo de etapas de cambio se plantea como una alternativa de prevención de bajo costo y de mayor impacto respecto al modelo informativo. El propósito del estudio fue evaluar el efecto de la Consejería en Vida Sana en el cambio de conducta de niños obesos entre 6 y 9 años de escuelas municipalizadas de la comuna de Macul, Región Metropolitana. Para esto se realizó un estudio piloto con diseño cuasi-experimental que incluyó a las madres/cuidadoras (N=50) de estos niños. La intervención consistió en tres sesiones de consejería en el hogar a madres/cuidadoras durante 16 semanas. Los resultados indican que la consejería contribuyó a que los niños del grupo intervenido disminuyeran el tiempo diario de televisión y mejoraran la calidad nutricional de sus colaciones, comparado a lo observado en el grupo control. Se recomienda que se confirme la efectividad de la consejería como estrategia de prevención en un estudio aleatorio con un tamaño muestral mayor.

Aberraciones cromosómicas in vitro para evaluar genotoxicidad de extractos de Abuta grandifolia (abuta) y Alchornea castaneifolia (hiporuro) / In vitro chromosome aberration analysis to evaluate genotoxicity of extracts of Abuta grandifolia (abuta) and Alchornea castaneifolia (hiporuro)

La evaluación de plantas medicinales usando parámetros de genotoxicidad, nos permite indicar si alguno de sus componentes puede provocar daño al material genético, a niveles génico o cromosómico. Este daño puede estimarse y determinará si el uso de la planta es conveniente o si por el contrario, el efecto benéfico aludido, se ve opacado por el probable efecto genotóxico. De forma alternativa, esta misma metodología permitiría detectar el efecto protector de una planta frente a la acción de mutágenos, lo cual redundaría en beneficio de los usuarios. Objetivo: Evaluar, in vitro, el efecto genotóxico del extractos de Abuta grandifolia, ôAbutaõ y Alchornea castaneifolia, ôHiporuroõ. Materiales y método: se realizaron cultivos de linfocitos obtenidos de sangre periférica, agregando los extractos de Abuta grandifolia, ôAbutaõ y Alchornea castaneifolia, ôHiporuroõ a diferentes concentraciones. Posteriormente, se realizó la evaluación citológica de aberraciones cromosómicas. Resultados: Se encontró un número elevado de aberraciones cromosómicas, tanto para el cultivo con Abuta como para el de Hiporuro. Este efecto se observó a diferentes concentraciones de extracto. Conclusiones: Las aberraciones cromosómicas encontradas en el presente trabajo, implicarían un efecto genotóxico de ambas plantas medicinales en el sistema in vitro empleado. Se requiere más estudios a diferentes niveles de organización que complementen los resultados reportados de este trabajo.

The evaluation of plants used in traditional medicine base don genotoxic parameters, allows researchers to determinate if some component could promote, genetic or chromosomal damage. This damage can be measured and, allow to determine the convenience of its use or, on the contrary, if its beneficial effect in undermined by the genotoxic effect. Moreover, this method would make it possible to detect the protective effect of the plant as opposed to a mutagen, which would enhance the benefit of its use. Objective: To evaluate the genotoxic effect of extracts of Abuta grandifolia, ôAbutaõ and Alchornea castaneifolia, ôHiporuroõ, using an in vitro test. Materials and method: Lymphocytes were cultured from peripheral blood, adding Abuta or Hiporuro extracts in different doses. Cytological evaluation of chromosome aberration was performed and registered. Results: An increased number of chromosome aberrations in Abuta and Hiporuro culture were found for different doses of extract. Conclusions: Chromosome aberrations found in the present work, would implicate a genotoxic effect in both plants in the system used. More studies are needed to complement the results of this research.

Improvement of leucocyte functions in ovariectomised aged rats after treatment with growth hormone, melatonin, oestrogens or phyto-oestrogens.

Ageing is accompanied by an impairment of the physiological activity of the nervous, endocrine and immune system, as well as in neuroendocrine-immune communication. However, age-related changes in this communication axis have been scarcely studied. In mammals, the process of ageing is associated with an important decline in the secretion of several hormones, such as growth hormone (GH), melatonin (MEL) and oestrogens (Os). Ovariectomy, a model of menopause in rats, has been found to lead to premature immunosenescence. In the present study, the effect of ovariectomy and the role of replacement therapies with GH, MEL, O and natural phyto-oestrogens (POs) have been assessed on several functions in leucocytes from the spleen and the axillary nodes of intact and ovariectomised rats. Chemotaxis, lymphoproliferative response to the mitogen concanavalin A (Con A), the release of interleukin-2 (IL-2) and the natural killer (NK) cell activity have been investigated. Age-controlled rats were used to compare immune functions in hormone treated aged rats with those in younger untreated animals. In all experimental groups, the immune impairment caused by ageing and ovariectomy was partially or completely reversed by hormone treatments. Since the immune system is a marker of health and a predictor of longevity, the results suggest that treatment with hormones could slow down the effects of the ageing process.

The European contribution to "Sugarbaker's protocol" for the treatment of colorectal peritoneal carcinomatosis.

INTRODUCTION: In 1981, Dr. PH Sugarbaker, challenging oncological orthodoxy, considered carcinomatosis to be a locoregional stage of the disease that was still susceptible to treatment with curative intent. To this end he developed a new therapeutic alternative based on the combined treatment. The macroscopic disease treated by maximum radical oncological cytoreductive surgery (through the peritonectomies described by him), followed by treatment of the residual microscopic disease with the direct intra-abdominal application of intraoperative chemotherapy with locoregional intensification, modulated by hyperthermia and early normothermic postoperative intra-abdominal chemotherapy. Using this new therapeutic regimen, known as "Sugarbaker s Protocol", his group has reported 45% survival rates in carcinomatosis of colorectal origin at 5 years, and, in selected groups of patients, 50% survival rates at 5 years. The scientific community, however, has criticized these results considering that: it is a personal experience, with a not homogenous treatment protocol with developmental modifications over time, that it is a retrospective non-randomized study, and finally that the cytostatics used in his protocol are obsolete. Various European groups have replied to these main criticisms confirming the good results that this new therapeutic alternative offers for patients with carcinomatosis of colorectal origin. The purpose of this article is to present these contributions. MATERIAL AND METHODS: All the articles published in the English language by European groups in the world s medical literature have been reviewed using the Pubmed-MEDLINE database to identify the relevant articles related to the treatment of carcinomatosis of colorectal origin using cytoreduction and intraperitoneal chemotherapy from January 1980 to January 2008. RESULTS: The European contribution during these 25 years in favour of the "Sugarbaker s Protocol" has consisted fundamentally in: a) one multicenter retrospective study; b) two randomized prospective phase III studies; and c) the use of oxaliplatin and irinotecan as new cytostatic agents in the protocols for intraperitoneal chemotherapy. At the same time, two new transcendental European contributions have been made in which the possibility has been considered of combined simultaneous treatment for patients with hepatic metastases and carcinomatosis, and the introduction, as a selection factor, of patients responsive to intravenous induction chemotherapy within the regimen of sandwich treatment (with systemic neoadjuvant and adjuvant chemotherapy) complementary to intraperitoneal chemotherapy. CONCLUSIONS: The results obtained by European groups using "Sugarbaker s protocol" and "Elias protocol" with oxaliplatin compel us to request that these treatments be considered by all professionals involved in the treatment of patients with colorectal carcinomatosis as the best treatment currently available for this condition. Furthermore a randomized, prospective, multicenter study should be carried out to clarify its value and the degree of scientific evidence. A validation of this treatment will change, in the future, the dogmatic consideration of carcinomatosis as an incurable disease stage.

Aportación europea al “protocolo de Sugarbaker” en el tratamiento de la carcinomatosis peritoneal colorrectal / The European contribution to "Sugarbaker's protocol" for the treatment of colorectal peritoneal carcinomatosis

Introducción: el Dr. P. H. Sugarbaker en 1981, desafiando la ortodoxia oncológica, consideró la carcinomatosis como un estadio locorregional de la enfermedad susceptible todavía de tratamiento con intención curativa. Para ello desarrolló una nueva alternativa terapéutica basada en el tratamiento combinado. La enfermedad macroscópica mediante la máxima cirugía citorreductora radical oncológica (merced a las peritonectomías por él descritas), seguido del tratamiento de la enfermedad microscópica residual con la aplicación directa intraabdominal, de quimioterapia de intensificación locorregional, intraoperatoria modulada por hipertermia y de quimioterapia intraabdominal normotérmica postoperatoria precoz. Con este nuevo esquema terapéutico, conocido como "Protocolo de Sugarbaker", su grupo ha publicado supervivencias en carcinomatosis de origen colorrectal de 45% a 5 años y en grupos selectos de pacientes supervivencia de 50% a 5 años. La comunidad científica, sin embargo, ha criticado estos resultados al considerar que: se trata de una experiencia personal, con un protocolo de tratamiento no homogéneo con modificaciones evolutivas en el tiempo, tratarse de un estudio retrospectivo no randomizado, y finalmente considerar que los citostáticos empleados en su protocolo son obsoletos. Diversos grupos europeos han dado respuesta a las principales objeciones, confirmando los buenos resultados que esta nueva alternativa terapéutica ofrece en pacientes con carcinomatosis de origen colorrectal. El objetivo de este trabajo es presentar estas aportaciones. Material y métodos: se han revisado todos los artículos publicados en lengua inglesa por grupos europeos en la literatura médica mundial usando la base de datos Pubmed-MEDLINE para identificar los artículos relevantes relacionados con el tratamiento de la carcinomatosis de origen colorrectal mediante citorreducción y quimioterapia intraperitoneal desde enero de 1980 a enero de 2008...(AU)

Introduction: in 1981, Dr. PH Sugarbaker, challenging oncological orthodoxy, considered carcinomatosis to be a locoregional stage of the disease that was still susceptible to treatment with curative intent. To this end he developed a new therapeutic alternative based on the combined treatment. The macroscopic disease treated by maximum radical oncological cytoreductive surgery (through the peritonectomies described by him), followed by treatment of the residual microscopic disease with the direct intra-abdominal application of intraoperative chemotherapy with locoregional intensification, modulated by hyperthermia and early normothermic postoperative intra-abdominal chemotherapy. Using this new therapeutic regimen, known as "Sugarbaker's Protocol", his group has reported 45% survival rates in carcinomatosis of colorectal origin at 5 years, and, in selected groups of patients, 50% survival rates at 5 years. The scientific community, however, has criticized these results considering that: it is a personal experience, with a not homogenous treatment protocol with developmental modifications over time, that it is a retrospective non-randomized study, and finally that the cytostatics used in his protocol are obsolete. Various European groups have replied to these main criticisms confirming the good results that this new therapeutic alternative offers for patients with carcinomatosis of colorectal origin. The purpose of this article is to present these contributions. Material and methods: all the articles published in the English language by European groups in the world's medical literature have been reviewed using the Pubmed-MEDLINE database to identify the relevant articles related to the treatment of carcinomatosis of colorectal origin using cytoreduction and intraperitoneal chemotherapy from January 1980 to January 2008...(AU)

Complicaciones respiratorias de la tetraplejia: una mirada a las alternativas terapéuticas actuales / Respiratory complications in tetraplegia: overview to current therapeutic alternatives

Respiratory complications are the first cause of death in patients with tetraplegia, including both the acute and chronic stage of the disease. They include a wide variety of respiratory problems, such as repeated pneumonias, atelectasis, unsatisfactory secretions manage, respiratory failure, hypoventilation, and other complex pathologies such as pulmonary embolism and sleep apnea syndrome. It has been postulated that the main cause of all these respiratory complications is weakness of inter costais and abdominal muscles, and partial or complete dysfunction of the diaphragm. Today we have multiple therapeutic alternatives to prevent, manage and specifically treat the multiple types of complications. The main objective of this article is to review the different therapeutical alternatives and encourage the study of this important topic.

Las complicaciones respiratorias son la principal causa de muerte en los pacientes con tetraplejia, tanto en el período agudo como crónico. En esta categoría se incluyen diversas alteraciones como neumonías recurrentes, atelectasias, mal manejo de las secreciones, insuficiencia respiratoria e hipoventilación. Además, son frecuentes patologías más complejas como el tromboembolismo pulmonar y la apnea obstructiva del sueño. Se postula que las causas principales de los problemas respiratorios son la debilidad de los músculos intercostales y abdominales, y la disfunción parcial o total del diafragma. Hoy en día existen múltiples alternativas terapéuticas para prevenir, manejar y tratar en forma específica las diversas complicaciones. El propósito de este artículo es revisar las opciones terapéuticas actualmente vigentes y despertar el interés entre los clínicos para profundizar más en este importante tema.

Cinnamtannin B-1 from bay wood exhibits antiapoptotic effects in human platelets.

Proanthocyanidins, such as cinnamtannin B-1, are polyphenolic compounds with antioxidant activity that induce apoptosis in a number of tumoral cells. We have now investigated the pro- or anti-apoptotic effects of cinnamtannin B-1 in human platelets. Platelet stimulation with thrombin induced cellular apoptosis, as detected by phosphatidylserine exposure and the activation of caspases-3 and -9. Pretreatment for 30 min with cinnamtannin B-1 impaired thrombin-induced apoptosis in platelets. Thrombin has been shown to induce H(2)O(2) generation in platelets, which induced similar apoptotic events than thrombin in these cells. Pretreatment with cinnamtannin B-1 reduced H(2)O(2)-induced phosphatidylserine exposure and caspase activation. Finally, platelet stimulation with thrombin induced translocation of caspases-3 and -9 to the cytoskeletal (Triton-insoluble) fraction, which is important for their activation and the development of apoptotic events. Pretreatment with cinnamtannin B-1 impaired translocation of caspases-3 and -9 to the cytoskeleton and, as a result, procaspases are accumulated in the Triton-soluble fraction. Our results provide evidence for the antiapoptotic actions of cinnamtannin B-1 in human platelets.

Seguridad de la resonancia mágnetica en pacientes con neuroestimuladores medulares: nuestra experiencia / Safety of magnetic resonance in patients with implanted spinal cord neurostimulators: our experience

Introducción: En la ultima década la resonancia magnética (RM) ha sido introducida como una herramienta rutinaria de diagnóstico clínico por imagen, siendo considerada como una prueba no invasiva y segura. Sin embargo se ha contraindicado su utilización en pacientes que poseen dispositivos electrónicos implantados, entre ellos neurostimuladores medulares y corticales. A diferencia del avance de la tecnología en neuroesti-mulación y su aplicación clínica, hay pocos estudios que avalen la seguridad de la RM en pacientes con neuroestimuladores implantados. Nuestra hipótesis es que la RM es un método diagnóstico seguro en los pacientes con neuroestimuladores implantados. Nuestro trabajo tiene como finalidad aportar más pruebas objetivas acerca de esta cuestión. Material y Métodos: Serie de 8 pacientes con neuroestimuladores implantados (ITRELL III modelo 7425, Medtronic) sometidos a 9 estudios de RM (1,5 T General Electric Sigma Excite) durante el 2005, siguiendo el protocolo de Liem van Dongen en los que se vigiló la aparición de efectos adversos relacionados, durante e inmediatamente después del estudio de imagen. Resultados: Durante los estudios de RM no se produjeron incidencias, ni efectos adversos, en ninguno de los casos, tanto en los que el estudio se realizó en zonas alejadas del implante del neuroestimulador, como en los que se realizó en la misma zona anatómica. Una vez concluido el estudio de RM no se objetivó ninguna referencia de los pacientes a sensaciones relacionadas con el calentamiento o interacción electromagnética de la RM con su neuroestimulador. Tampoco se produjo ningún fallo en la reprogramación de los neuroestimuladores, excepto en un caso en el que fue imposible reprogramar el neuroestimulador una vez concluido el estudio de RM. Conclusiones: Todo parece indicar que en la mayoría de los casos la RM puede ser aplicada de forma segura en pacientes con sistemas de neruroestimulación implantados, siguiendo el protocolo de Liem-van Dongen, pero al parecer existen determinadas circunstancias en las que no queda totalmente claro la fiabilidad de esta recomendación. En el caso de la paciente en la que no fue posible reprogramar su neuroestimulador después de la RM en nuestro estudio, pudiera haber ocurrido un fallo de batería, o bien un daño en el circuito electrónico del generador. El no haber podido examinar el generador con problemas, no nos permite establecer una sospecha fundada sobre el conjunto de hechos que pueden haber concurrido en la producción del fallo. En cualquier caso se impone la realización de más estudios para esclarecer de forma más fiable las condiciones seguras de realización de la RM en pacientes con neuroestimuladores implantados (AU)

Aims: Over the past decade, nuclear magnetic resonance imaging (MRI) has been introduced as a safe, non-invasive routine clinical diagnostic tool. However, its use has been contraindicated in patients with implanted electronic devices, such as motor cortex and spinal cord neurostimulators. Despite the rapid growth in neurostimulation technology and its clinical application, there have been few studies addressing the safety of performing MRI procedures in patients with implanted neurostimulators. Our hypothesis is that MRI is a safe diagnostic technique in patients with implanted neurostimulators. The aim of our study is to offer some objective proof towards this point. Methods: Eight patients with implanted neurostimulators (ITRELL III Model 7425, Medtronic) undergoing 9 MRI procedures (1,5 T General Electric Sigma Excite) in 2005 are presented, following the Liem van Dongen´s protocol, with a focus in the appearance of adverse effects, during and immediately after the imaging study. Results: During the MRI studies there were no overall adverse effects detected in any case, in those in which the scanning was performed on a location away from the site of the implanted neurostimulators, nor in those in which it was performed in the same anatomic region. Once the MRI study concluded, no patient reported any sensation of discomfort attributable to heating or the electromagnetic interaction of the MRI with the neurostimulators. Neither there was any failure in the neurostimulators rescheduling, except in one case in which it was impossible its reprogrammation once the study was completed. Conclusions: In general, all these investigations indicate that in most cases MRI can be performed safely in patients with implanted stimulators, following the Liem van Dongen´s protocol, but it seems that under some circumstances this recommendation is not completely reliable. In the case of our patient in which the neurostimulator was impossible to reschedule after the MRI, this may have been caused by a battery failure, or there could have been a breakup in the generator’s electronic circuit. As the generator could not be examined, a hypothesis about the train of events leading to its failure was not established. In any case more studies are desirable to reliably explain the safety conditions required for the performance of MRI in patients with implanted neurostimulators (AU)

Effect of isoflavone administration on age-related hepatocyte changes in old ovariectomized femal Wistar rats.

Aging seems to be due to the accumulation of oxidative damage in cells and molecules. On the other hand, menopause and ovariectomy induce deleterious effects on different organs and systems that have been shown to be counteracted by estrogens and in a not so evident form also with phytoestrogens. The present study has investigated whether the administration of a commercial soy extract that contains approximately 10% isoflavones was able to modify some parameters related to oxidative stress and inflammation in hepatocytes isolated from old ovariectomized female Wistar rats. Eighteen 22-month-old animals that had been previously ovariectomized at 12 months of age were divided into four groups: ovariectomized control rats, estradiol-treated ovariectomized females and ovariectomized rats treated with isoflavones. Six intact female rats of 2 months of age were used as reference group. Hepatocytes were isolated and cultured, and carbon monoxide (CO) and nitric oxide (NO) release, as well as adenosyl triphosphate (ATP), cyclic guanosyl monophosphate (cGMP), phosphatidylcholine (PC) and lipid peroxide (LPO) content of cells were evaluated. Uterus was also removed and weighed. Hepatocytes isolated from old ovariectomized rats showed a decrease in ATP content as compared to young animals. Age also induced an increase in LPO cell content. NO, CO and cGMP were augmented with age, and PC synthesis showed a dramatic reduction. Treatment with either estradiol or isoflavones were able to improve all the mentioned parameters altered in hepatocytes isolated from old ovariectomized rats, and the magnitude of the improvement was similar for both treatments. Ovariectomy induced a significant reduction in uterine weight, which was significantly counteracted by estradiol treatment but not by isoflavone administration. In conclusion, the administration of a soy extract containing isoflavones seems to prevent oxidative changes in hepatocytes isolated from old ovariectomized female rats, without modifying uterus weight.

Capillary electrophoresis for caffeine and pyroglutamate determination in coffees study of the in vivo effect on learning and locomotor activity in mice.

In a preliminary study pyroglutamate showed to be over 10 times increased in some lyophilised coffees with respect to brewed or filtered coffees, and probably that increase is related to some stage of the industrial process. Pyroglutamate is known to have a number of remarkable cognitive enhancing effects, which could be also related to the properties of coffee traditionally associated to caffeine. Pyroglutamate improves memory and learning and has anti-anxiety effects in rats. Therefore, a method has been developed and validated for the simultaneous determination of caffeine and pyroglutamate in coffee by capillary electrophoresis. Separation conditions employed MECK conditions with 50 mM borate buffer at pH 9.5 with 130 mM SDS. The applied potential was 10 kV and detection was performed at 200 nm. Afterwards, 10 soluble coffees from the market were measured and caffeine and pyroglutamate levels were compared. Those coffees with higher pyroglutamate with or without caffeine were preliminarily tested for sedative/stimulant properties and cognition enhancing effects in mice. The most relevant finding was a partial reversal of scopolamine-induced amnesia in the passive avoidance paradigm after oral administration of one coffee.

Adjuvant radiochemotherapy in the treatment of completely resected, locally advanced gastric cancer.

PURPOSE: To analyze the efficacy and toxicity of adjuvant whole abdomen irradiation (WAI) and concomitant chemotherapy in the treatment of completely resected, high-risk gastric cancer. METHODS AND MATERIALS: Between October 1990 and September 1997, 52 patients with completely resected gastric cancer, with lymph node and/or serosal involvement, were treated. Ages were 16-78 (median, 53.5) years. Treatment was either total- or sub-total gastrectomy, followed by WAI, 2100 cGy/21 fractions plus a 2400 cGy/16 fractions boost to the tumor bed. Chemotherapy consisted of either 5-fluorouracil (5-FU) 450-500 mg/m(2) i.v. for 5 days first and 5th week or 200-300 mg/m(2) continuous infusion during irradiation. No further chemotherapy was given. RESULTS: With a minimum follow-up of 30 months and a median follow-up of 43.5 months, 25 of the 52 patients have died. Overall 5-year survival rate is 54%. Three patients sustained Grade 3-5 complications. Two patients with Grade 5 complications (malabsorption syndrome) died 31 and 56 months after the beginning of the treatment, respectively, with no evidence of recurrent tumor. For patients with involvement of the lymph nodes alone (n = 19) the 5-year survival was 69%, which was significantly better than the 36% 5-year survival observed for those patients with both serosal and lymph node involvement (n = 26, p = 0.004). CONCLUSION: Adjuvant radiochemotherapy, WAI, and concomitant 5-FU, is a feasible and a fairly well-tolerated treatment for patients with locally advanced (involvement of the lymph nodes or serosa) gastric carcinoma who undergo complete resection. The 54% overall 5-year survival compares favorably with the survival reported after surgery alone for those patients.

Giardia lamblia: incorporation of free and conjugated fatty acids into glycerol-based phospholipids.

Giardia lamblia trophozoites are flagellated protozoa that inhabit the human small intestine, where they are exposed to various dietary lipids and fatty acids. It is believed that G. lamblia, which colonizes a lipid-rich environment of the human small intestine, is unable to synthesize phospholipids, long-chain fatty acids, and sterols de novo. Therefore, it is possible that this protozoan has developed a special process for acquiring lipids from its host. We have previously shown that G. lamblia can take up saturated fatty acids and incorporate them into phosphatidylglycerol (PG) and other glycerol-based phospholipids (Stevens et al., Experimental Parasitology, 86, 133-143, 1997). In the present study, an attempt has been made to investigate the underlying mechanisms of transesterification and interesterification reactions of giardial phospholipids by free and conjugated fatty acids. Results show that exogenously supplied, unsaturated, fatty acids were taken up by Giardia and incorporated into various phosphoglycerides, including PG. To test whether this intestinal pathogen can utilize conjugated fatty acids, live trophozoites were exposed to either [3]H;cbphosphatidylcholine (PC), where the fatty acid was 3H-labeled at its sn2 position, or to [14C]lyso-PC (fatty acid was 14C-labeled at the sn1 position) for 90 min, followed by phospholipid analysis using thin-layer chromatography. The results suggest that conjugated fatty acids, like free fatty acids, were incorporated into PG. It was also observed that aristolochic acid, an inhibitor of Ca2+-ionophore-stimulated phospholipase A2, decreased the transfer of fatty acids from [3H]PC to PG, indicating that giardial phospholipases were involved in these esterification reactions. Additional experiments, which include culturing trophozoites in serum-supplemented and serum-deprived medium, along with numerous biochemical analyses suggest that (i) PG is a major transesterified and interesterified product, (ii) it is likely that giardial phospholipases are involved in esterification reactions, (iii) in G. lamblia, PG is localized in perinuclear membranes, as well as intracellularly, but not in the plasma membrane, and (iv) various synthetic analogs of PG inhibit the growth of the parasite in vitro. These studies suggest that PG is an important phospholipid of Giardia and a potential target for lipid-based chemotherapy against giardiasis.

The influence of reproductive stage on the selenium status of sheep in a low-selenium region.

The selenium status of sheep was evaluated during the reproductive stage in a region of low selenium level. Serum selenium concentration, whole blood glutathione peroxidase activity (GSH-Px), which is a good indicator of protection against oxidative damage, as well as the activities of creatine kinase (CK) and aspartate aminotransferase (AST), the plasma indicators of muscle damage, were evaluated in a group of ewes during gestation and lactation and in their lambs. The selenium requirements of ewes were found to increase during lactation. There were no differences in GSH-Px activity between the experimental and the control groups throughout the reproductive stage. In the second half of pregnancy GSH-Px activity was subnormal. In spite of this, no evidence of existing pathologic conditions associated with selenium deficiency was found, since the muscle markers CK and AST were within the normal range. In the same way, no distinct symptoms of nutritional myopathy were observed in the lambs, suggesting that the low selenium level found in the ewes did not cause alterations in their development.

Anemone toxin II unmasks two conductance states in neuronal sodium channels.

Anemone toxin II (ATX)-modified voltage-dependent neuronal sodium channels were studied in planar lipid bilayers. ATX-modified channels displayed two predominant conducting states: a short-lived (ms-s) high-conductance (approximately 65 pS) state and a long-lived (s-min) low-conductance (approximately 10 pS) state. The high-conductance state underwent brief closures (ms) and the low-conductance state underwent long closures (s). The probability of detecting these states was time- and voltage-dependent. The channel's fractional open time (fo) due to the high-conductance state increased with depolarization and had a midpoint potential (Va) of -36 mV and an apparent gating charge (Za) of 2.8. The channel's fo due to the low-conductance state increased with depolarization and had a Va of +13 mV and a Za of 1.4. At positive potentials, ATX-modified channels slowly (minutes) entered an absorbing non-conducting state. The permeability ratio of Na+/K+ was 2 and 4 for the low- and high-conductance states, respectively. The saxitoxin analog C3 blocked ATX-modified sodium channels with high affinity (Kd(60-90 mV) = 410 nM, 0.5 M NaCl). The data suggest that upon a depolarization step, ATX-modified channels enter rapidly (ms) into a high-conductance state and more slowly (s-min) into a low-conductance state. Also as the membrane potential becomes more positive, the equilibrium is shifted from the high- to the low-conductance state and from the conducting states to an absorbing non-conducting state.