A Novel Pathogenic Variant in the MN1 Gene in a Patient Presenting with Rhombencephalosynapsis and Craniofacial Anomalies, Expanding MN1 C-terminal Truncation Syndrome.

Meningioma-1 is a transcription activator that regulates mammalian palate development and is required for appropriate osteoblast proliferation, motility, differentiation, and function. Microdeletions involving the MN1 gene have been linked to syndromes including craniofacial anomalies, such as Toriello-Carey syndrome. Recently, truncating variants in the C-terminal portion of the MN1 transcriptional factor have been linked to a characteristic and distinct phenotype presenting with craniofacial anomalies and partial rhombencephalosynapsis, a rare brain malformation characterized by midline fusion of the cerebellar hemispheres with partial or complete loss of the cerebellar vermis. It has been called MN1 C-terminal truncation (MCTT) syndrome or CEBALID (Craniofacial defects, dysmorphic Ears, Brain Abnormalities, Language delay, and Intellectual Disability) and suggested to be caused by dominantly acting truncated protein MN1 instead of haploinsufficiency. As a proto-oncogene, MN1 is also involved in familial meningioma. In this study, we present a novel case of MCTT syndrome in a female patient presenting with craniofacial anomalies and rhombencephalosynapsis, harboring a de novo pathogenic variant in the MN1 gene: c.3686_3698del, p.(Met1229Argfs*87).

The Nutrition in Early Life and Asthma (NELA) birth cohort study: Rationale, design, and methods.

BACKGROUND: Primary prevention strategies for asthma are lacking. Its inception probably starts in utero and/or during the early postnatal period as the developmental origins of health and disease (DOHaD) paradigm suggests. OBJECTIVES: The main objective of Nutrition in Early Life and Asthma (NELA) cohort study is to unravel whether the following factors contribute causally to the developmental origins of asthma: (1) maternal obesity/adiposity and foetal growth; (2) maternal and child nutrition; (3) outdoor air pollution; (4) endocrine disruptors; and (5) maternal psychological stress. Maternal and offspring biological samples are used to assess changes in offspring microbiome, immune system, epigenome and volatilome as potential mechanisms influencing disease susceptibility. POPULATION: Randomly selected pregnant women from three health areas of Murcia, a south-eastern Mediterranean region of Spain, who fulfilled the inclusion criteria were invited to participate at the time of the follow-up visit for routine foetal anatomy scan at 19-22 weeks of gestation, at the Maternal-Fetal Medicine Unit of the "Virgen de la Arrixaca" University Clinical Hospital over a 36-month period, from March 2015 to April 2018. DESIGN: Prospective, population-based, maternal-child, birth cohort study. METHODS: Questionnaires on exposures and outcome variables were administered to mothers at 20-24 gestation week; 32-36 gestation week; and delivery. Children were surveyed at birth, 3 and 18 months of age and currently at 5 years. Furthermore, physical examinations were performed; and different measurements and biological samples were obtained at these time points. PRELIMINARY RESULTS: Among the 1350 women invited to participate, 738 (54%) were finally enrolled in the study and 720 of their children were eligible at birth. The adherence was high with 612 children (83%) attending the 3 months' visit and 532 children (72%) attending the 18 months' visit. CONCLUSION: The NELA cohort will add original and unique knowledge to the developmental origins of asthma.

Albuminuria Pre-Emptively Identifies Cardiac Patients at Risk of Contrast-Induced Nephropathy.

Contrast-induced nephropathy (CIN) is a complication associated with the administration of contrast media (CM). The CIN diagnosis is based on creatinine, a biomarker late and insensitive. The objective proposed was to evaluate the ability of novel biomarkers to detect patients susceptible to suffering CIN before CM administration. The study was carried out with patients undergoing cardiac catheterization involving CM. Patients were divided into two groups: (1) CIN, patients who developed this pathology; (2) control, patients who did not suffer CIN. Prior to the administration of CM, urine samples were collected to measure proteinuria, N-acetyl-ß-d-glucosaminidase, neutrophil gelatinase-associated lipocalin and kidney injury molecule-1, albumin, transferrin, t-gelsolin and GM2 ganglioside activator protein (GM2AP). The risk factors advanced age, low body mass index and low estimated glomerular filtration rate; and the urinary biomarkers albumin, transferrin and GM2AP showed significant predictive capacity. Of all of them, albuminuria demonstrated the highest diagnostic power. When a cutoff point was established for albuminuria at values still considered subclinical (10-30 µg/mg Cru), it was found that there was a high incidence of CIN (40-75%). Therefore, albuminuria could be applied as a new diagnostic tool to prevent and predict CIN with P4 medicine criteria, independently of risk factors and comorbidities.

Early prediction of developing spontaneous activity in cultured neuronal networks.

Synchronization and bursting activity are intrinsic electrophysiological properties of in vivo and in vitro neural networks. During early development, cortical cultures exhibit a wide repertoire of synchronous bursting dynamics whose characterization may help to understand the parameters governing the transition from immature to mature networks. Here we used machine learning techniques to characterize and predict the developing spontaneous activity in mouse cortical neurons on microelectrode arrays (MEAs) during the first three weeks in vitro. Network activity at three stages of early development was defined by 18 electrophysiological features of spikes, bursts, synchrony, and connectivity. The variability of neuronal network activity during early development was investigated by applying k-means and self-organizing map (SOM) clustering analysis to features of bursts and synchrony. These electrophysiological features were predicted at the third week in vitro with high accuracy from those at earlier times using three machine learning models: Multivariate Adaptive Regression Splines, Support Vector Machines, and Random Forest. Our results indicate that initial patterns of electrical activity during the first week in vitro may already predetermine the final development of the neuronal network activity. The methodological approach used here may be applied to explore the biological mechanisms underlying the complex dynamics of spontaneous activity in developing neuronal cultures.

Prorocentroic Acid, a Neuroactive Super-Carbon-Chain Compound from the Dinoflagellate Prorocentrum hoffmannianum.

Prorocentroic acid (PA) was isolated from the dinoflagellate Prorocentrum hoffmannianum. Relative configurations for its 35 asymmetric centers were determined by analysis of NMR data including heteronuclear couplings and quantum mechanical calculations. PA was tested by using murine cortical neurons grown on microelectrode arrays. Long-term exposure to subtoxic concentrations induced a significant reorganization of neuronal signaling, mainly by changes in the bursting activity. The observed effects could be due to the activation of a plasticity process.

A meta-analysis of preclinical studies using antioxidants for the prevention of cisplatin nephrotoxicity: implications for clinical application.

Cisplatin is an effective chemotherapeutic drug whose clinical use and efficacy are limited by its nephrotoxicity, which affects mainly the renal tubules and vasculature. It accumulates in proximal and distal epithelial tubule cells and causes oxidative stress-mediated cell death and malfunction. Consequently, many antioxidants have been tested for their capacity to prevent cisplatin nephrotoxicity. In this study, we made a systematic review of the literature and meta-analyzed 152 articles, which tested the nephroprotective effect of isolated compounds or mixtures of natural origin on cisplatin nephrotoxicity in preclinical models. This meta-analysis identified the most effective candidates and examined the efficacy obtained by antioxidants administered by the oral and intraperitoneal routes. By comparing with a recent, similar meta-analysis performed on clinical studies, this article identifies a disconnection between preclinical and clinical research, and contextualizes, discusses, and integrates the existing preclinical information toward the optimized selection of candidates to be further explored (clinical level). Despite proved efficacy, this article discusses the barriers limiting the clinical development of natural mixtures, such as those in extracts from Calendula officinalis flowers and Heliotropium eichwaldii roots. On the contrary, isolated compounds are more straightforward candidates, among which arjunolic acid and quercetin stand out in this meta-analysis.

Glucosylpolyphenols as Inhibitors of Aß-Induced Fyn Kinase Activation and Tau Phosphorylation: Synthesis, Membrane Permeability, and Exploratory Target Assessment within the Scope of Type 2 Diabetes and Alzheimer's Disease.

Despite the rapidly increasing number of patients suffering from type 2 diabetes, Alzheimer's disease, and diabetes-induced dementia, there are no disease-modifying therapies that are able to prevent or block disease progress. In this work, we investigate the potential of nature-inspired glucosylpolyphenols against relevant targets, including islet amyloid polypeptide, glucosidases, and cholinesterases. Moreover, with the premise of Fyn kinase as a paradigm-shifting target in Alzheimer's drug discovery, we explore glucosylpolyphenols as blockers of Aß-induced Fyn kinase activation while looking into downstream effects leading to Tau hyperphosphorylation. Several compounds inhibit Aß-induced Fyn kinase activation and decrease pTau levels at 10 µM concentration, particularly the per-O-methylated glucosylacetophloroglucinol and the 4-glucosylcatechol dibenzoate, the latter inhibiting also butyrylcholinesterase and ß-glucosidase. Both compounds are nontoxic with ideal pharmacokinetic properties for further development. This work ultimately highlights the multitarget nature, fine structural tuning capacity, and valuable therapeutic significance of glucosylpolyphenols in the context of these metabolic and neurodegenerative disorders.

Urinary transferrin pre-emptively identifies the risk of renal damage posed by subclinical tubular alterations.

Nephrotoxicity is an important limitation to the clinical use of many drugs and contrast media. Drug nephrotoxicity occurs in acute, subacute and chronic manifestations ranging from glomerular, tubular, vascular and immunological phenotypes to acute kidney injury. Pre-emptive risk assessment of drug nephrotoxicity poses an urgent need of precision medicine to optimize pharmacological therapies and interventional procedures involving nephrotoxic products in a preventive and personalized manner. Biomarkers of risk have been identified in animal models, and risk scores have been proposed, whose clinical use is abated by their reduced applicability to specific etiological models or clinical circumstances. However, our present data suggest that the urinary level of transferrin may be indicative of risk of renal damage, where risk is induced by subclinical tubular alterations regardless of etiology. In fact, urinary transferrin pre-emptively correlates with the subsequent renal damage in animal models in which risk has been induced by drugs and toxins affecting the renal tubules (i.e. cisplatin, gentamicin and uranyl nitrate); whereas transferrin shows no relation with the risk posed by a drug affecting renal hemodynamics (i.e. cyclosporine A). Our experiments also show that transferrin increases in the urine in the risk state (i.e. prior to the damage) precisely as a consequence of reduced tubular reabsorption. Finally, urinary transferrin pre-emptively identifies subpopulations of oncological and cardiac patients at risk of nephrotoxicity. In perspective, urinary transferrin might be further explored as a wider biomarker of an important mechanism of predisposition to renal damage induced by insults causing subclinical tubular alterations.

Población y metodología del estudio SIMETAP: Prevalencia de factores de riesgo cardiovascular, enfermedades cardiovasculares y enfermedades metabólicas relacionadas / Population and methodology of the SIMETAP study: Prevalence of cardiovascular risk factors, cardiovascular diseases, and related metabolic diseases

La prevención de la enfermedad cardiovascular se fundamenta en la detección y control de los factores de riesgo cardiovascular (FRCV). En España existen importantes diferencias territoriales tanto en la prevalencia como en el grado de control de los FRCV. En la última década ha habido una mejora del control de la hipertensión y la dislipidemia, pero un empeoramiento de los factores de riesgo cardiometabólicos relacionados con la obesidad y la diabetes. El estudio SIMETAP es un estudio observacional descriptivo transversal realizado en 64 centros de atención primaria de la Comunidad de Madrid. El objetivo principal es determinar las tasas de prevalencia de FRCV, de las enfermedades cardiovasculares y de las enfermedades metabólicas relacionadas con el riesgo cardiovascular. El presente artículo informa sobre las características basales de la población, la metodología del estudio, y las definiciones de los parámetros y enfermedades en estudio. Se seleccionaron 6.631 sujetos de estudio mediante una muestra aleatoria base poblacional. Se determinaron variables antropométricas, estilos de vida, presión arterial, parámetros bioquímicos, y tratamientos farmacológicos. Las prevalencias crudas más elevadas se detectaron en tabaquismo, inactividad física, obesidad, prediabetes, diabetes, hipertensión, dislipidemias y síndrome metabólico. Para valorar la verdadera dimensión epidemiológica de estas enfermedades y FRCV, es necesario realizar un análisis pormenorizado de tasas de prevalencia estratificadas por grupos etarios y de las tasas de prevalencia ajustadas por edad y sexo

The prevention of cardiovascular disease is based on the detection and control of cardiovascular risk factors (CVRF). In Spain there are important geographical differences both in the prevalence and in the level of control of the CVRF. In the last decade there has been an improvement in the control of hypertension and dyslipidaemia, but a worsening of cardio-metabolic risk factors related to obesity and diabetes. The SIMETAP study is a cross-sectional descriptive, observational study being conducted in 64 Primary Care Centres located at the Community of Madrid. The main objective is to determine the prevalence rates of CVRF, cardiovascular diseases, and metabolic diseases related to cardiovascular risk. A report is presented on the baseline characteristics of the population, the study methodology, and the definitions of the parameters and diseases under study. A total of 6,631 study subjects were selected using a population-based random sample. The anthropometric variables, lifestyles, blood pressure, biochemical parameters, and pharmacological treatments were determined. The highest crude prevalences were detected in smoking, physical inactivity, obesity, prediabetes, diabetes, hypertension, dyslipidaemias, and metabolic syndrome. A detailed analysis needs to be performed on the prevalence rates, stratified by age groups, and prevalence rates adjusted for age and sex to assess the true epidemiological dimension of these CVRF and diseases

Population and methodology of the SIMETAP study: Prevalence of cardiovascular risk factors, cardiovascular diseases, and related metabolic diseases. / Población y metodología del estudio SIMETAP: Prevalencia de factores de riesgo cardiovascular, enfermedades cardiovasculares y enfermedades metabólicas relacionadas.

The prevention of cardiovascular disease is based on the detection and control of cardiovascular risk factors (CVRF). In Spain there are important geographical differences both in the prevalence and in the level of control of the CVRF. In the last decade there has been an improvement in the control of hypertension and dyslipidaemia, but a worsening of cardio-metabolic risk factors related to obesity and diabetes. The SIMETAP study is a cross-sectional descriptive, observational study being conducted in 64 Primary Care Centres located at the Community of Madrid. The main objective is to determine the prevalence rates of CVRF, cardiovascular diseases, and metabolic diseases related to cardiovascular risk. A report is presented on the baseline characteristics of the population, the study methodology, and the definitions of the parameters and diseases under study. A total of 6,631 study subjects were selected using a population-based random sample. The anthropometric variables, lifestyles, blood pressure, biochemical parameters, and pharmacological treatments were determined. The highest crude prevalences were detected in smoking, physical inactivity, obesity, prediabetes, diabetes, hypertension, dyslipidaemias, and metabolic syndrome. A detailed analysis needs to be performed on the prevalence rates, stratified by age groups, and prevalence rates adjusted for age and sex to assess the true epidemiological dimension of these CVRF and diseases.

Macromastia en la adolescencia: fibroadenoma gigante juvenil de la mama / Macromastia in adolescence: giant juvenile fibroadenoma of the breast

No disponible

Therapeutic failure with thalidomide in patients with recurrent intestinal bleeding due to angiodysplasias / Fracaso terapéutico a talidomida en paciente con sangrado intestinal recurrente debido a angiodisplasias

Angiodysplasias are one of the reasons of gastrointestinal bleeding, whose origin is usually due to vascular malformations. There are different types of therapies for angiodysplasia such as endoscopic, angiographic and pharmacological techniques. Among the last ones, there is little variety of effective drugs to treat the disease. We describe the therapeutic failure with thalidomide in a male with recurrent gastrointestinal bleeding due to angiodysplasias. A thorough diagnostic work-up, including gastroscopy, enteroscopy, angiography and capsule endoscopy were performed. Despite treatment with high-dose somatostatin analogues and oral iron, the patient continued bleeding. The patient was administered then thalidomide for three months with no clinical response. Thalidomide had to be withdrawn owing to adverse effects (AU)

Una de las causas de sangrado a nivel gastrointestinal son las angiodisplasias, cuyo origen suele deberse a malformaciones a nivel vascular. Existen distintos tipos de terapias para las angiodisplasias, como son las técnicas endoscópicas, angiográficas y farmacológicas. Dentro de estas últimas existe poca variedad de fármacos efectivos para dicha patología. Se describe el fracaso terapéutico con talidomida en un varón con sangrado gastrointestinal recurrente debido a angiodisplasias. Se le realiza un diagnóstico completo, incluyendo gastroscopia, enteroscopia, angiografía y cápsula endoscópica. A pesar del tratamiento con análogos de la somatostatina a altas dosis y hierro oral, el paciente continuó sangrando. El paciente recibió talidomida durante tres meses sin respuesta clínica. La talidomida tuvo que ser retirada debido a los efectos adversos y a la falta de eficacia (AU)

Therapeutic failure with thalidomide in patients with recurrent intestinal bleeding due to angiodysplasias.

Angiodysplasias are one of the reasons of gastrointestinal bleeding, whose origin is usually due to vascular malformations. There are different types of therapies for angiodysplasia such as endoscopic, angiographic and pharmacological techniques. Among the last ones, there is little variety of effective drugs to treat the disease. We describe the therapeutic failure with thalidomide in a male with recurrent gastrointestinal bleeding due to angiodysplasias. A thorough diagnostic work-up, including gastroscopy, enteroscopy, angiography and capsule endoscopy were performed. Despite treatment with high-dose somatostatin analogues and oral iron, the patient continued bleeding. The patient was administered then thalidomide for three months with no clinical response. Thalidomide had to be withdrawn owing to adverse effects.

Una de las causas de sangrado a nivel gastrointestinal son las angiodisplasias, cuyo origen suele deberse a malformaciones a nivel vascular. Existen distintos tipos de terapias para las angiodisplasias, como son las técnicas endoscópicas, angiográficas y farmacológicas. Dentro de estas últimas existe poca variedad de fármacos efectivos para dicha patología. Se describe el fracaso terapéutico con talidomida en un varón con sangrado gastrointestinal recurrente debido a angiodisplasias. Se le realiza un diagnóstico completo, incluyendo gastroscopia, enteroscopia, angiografía y cápsula endoscópica. A pesar del tratamiento con análogos de la somatostatina a altas dosis y hierro oral, el paciente continuó sangrando. El paciente recibió talidomida durante tres meses sin respuesta clínica. La talidomida tuvo que ser retirada debido a los efectos adversos y a la falta de eficacia.

Respuesta de los autores: Medicina familiar y comunitaria y la enfermedad pulmonar obstructiva crónica / Author's reply: Family and community medicine and chronic obstructive pulmonary disease

No disponible

Estudio ARAPOC: prevalencia de síntomas respiratorios y enfermedad obstructiva crónica en población general / ARAPOC Study: Prevalence of respiratory symptoms and chronic obstructive pulmonary disease in the general population

OBJETIVO: El objetivo de este trabajo fue conocer la prevalencia de síntomas respiratorios y de EPOC, así como las características de esta población en Aragón (España). Diseño y emplazamiento: Estudio epidemiológico, transversal, en población entre 40 y 75 años. Los sujetos fueron elegidos de forma aleatoria y estratificada por edad y sexo a partir de los datos de la tarjeta sanitaria del Servicio Aragonés de Salud. PARTICIPANTES: Un total de 1.185 sujetos aceptaron colaborar. MEDICIONES PRINCIPALES: Un cuestionario sociodemográfico y clínico y espirometría forzada antes y después de una prueba broncodilatadora. El diagnóstico de EPOC se realizaba según los criterios de la guía GOLD (cociente FEV1/CVF < 0,7). RESULTADOS: La prevalencia de EPOC alcanzó un 10,4% (IC: 9,8-11,0%), un 16,9% en hombres y un 5,7% en mujeres. Los síntomas respiratorios aparecieron en un 58% de la población general. Existía mayor prevalencia de EPOC en las mujeres que en otros estudios. Los factores asociados a desarrollar EPOC fueron ser hombre, tener más edad, mayor índice tabáquico y menor nivel de estudios. El 78,9% de los pacientes con EPOC no estaban diagnosticados. Los diagnosticados fueron de más edad, más fumadores, con EPOC más graves o con peor calidad de vida. CONCLUSIONES: La alta prevalencia de EPOC y el importante nivel de infradiagnóstico nos permite creer que el diagnóstico precoz de esta enfermedad es todavía una asignatura pendiente. Necesitamos desarrollar nuevas estrategias para atajar este problema

OBJECTIVE: The aim of this study was to determine the prevalence of respiratory symptoms and COPD, as well as the characteristics of this population in Aragon (Spain). Design and LOCATION: It is a cross-sectional epidemiological study in a population between 40 and 75 years of age. Subjects were randomly selected and stratified by age and sex using the data from the health card of the Aragonese Health Service. PARTICIPANTS: A total of 1185 subjects agreed to participate. MAIN MEASUREMENTS: A sociodemographic questionnaire and spirometry before and after bronchodilator test. The diagnosis of COPD was made according to the criteria of the GOLD guide (FEV1/FVC<0.7). RESULTS: COPD prevalence was 10.4%, 16.9% in men and 5.7% in women. Respiratory symptoms appeared in 58% of the general population. There was a higher prevalence of COPD in women than in other studies. Factors associated with developing COPD were, being male, increasing age, smoking more, and a lower education. More than three-quarters (78.9%) of COPD were not diagnosed. Diagnosis was associated with, being older, more smoking more, more severe COPD or poorer quality of life. CONCLUSIONS: The high prevalence of COPD and the significant level of underdiagnoses lead to believe that early diagnosis of this disease is still a pending issue. New strategies need to be developed to resolve this problem

[ARAPOC Study: Prevalence of respiratory symptoms and chronic obstructive pulmonary disease in the general population]. / Estudio ARAPOC: prevalencia de síntomas respiratorios y enfermedad obstructiva crónica en población general.

OBJECTIVE: The aim of this study was to determine the prevalence of respiratory symptoms and COPD, as well as the characteristics of this population in Aragon (Spain). DESIGN AND LOCATION: It is a cross-sectional epidemiological study in a population between 40 and 75 years of age. Subjects were randomly selected and stratified by age and sex using the data from the health card of the Aragonese Health Service. PARTICIPANTS: A total of 1185 subjects agreed to participate. MAIN MEASUREMENTS: A sociodemographic questionnaire and spirometry before and after bronchodilator test. The diagnosis of COPD was made according to the criteria of the GOLD guide (FEV1/FVC<0.7). RESULTS: COPD prevalence was 10.4%, 16.9% in men and 5.7% in women. Respiratory symptoms appeared in 58% of the general population. There was a higher prevalence of COPD in women than in other studies. Factors associated with developing COPD were, being male, increasing age, smoking more, and a lower education. More than three-quarters (78.9%) of COPD were not diagnosed. Diagnosis was associated with, being older, more smoking more, more severe COPD or poorer quality of life. CONCLUSIONS: The high prevalence of COPD and the significant level of underdiagnoses lead to believe that early diagnosis of this disease is still a pending issue. New strategies need to be developed to resolve this problem.

Cooperative hydrogen bonding in glyco-oligoamides: DNA minor groove binders in aqueous media.

A strategy to create cooperative hydrogen-bonding centers by using strong and directional intramolecular hydrogen-bonding motifs that can survive in aqueous media is presented. In particular, glyco-oligoamides, a family of DNA minor groove binders, with cooperative and non-cooperative hydrogen-bonding donor centers in the carbohydrate residues have been designed, synthesized, and studied by means of NMR spectroscopy and molecular modeling methods. Indeed, two different sugar moieties, namely, ß-D-Man-Py-γ-Py-Ind (1; Ind=indole, Man=mannose, Py=pyrrole) and ß-D-Tal-Py-γ-Py-Ind (2; Tal=talose), were chosen according to our design. These sugar molecules should present one- or two-directional intramolecular hydrogen bonds. The challenge has been to study the conformation of the glyco-oligoamides at low temperature in physiological media by detecting the exchangeable protons (amide NH and OH resonances) by means of NMR spectroscopic analysis. In addition, two more glyco-oligoamides with non-cooperative hydrogen-bonding centers, that is, ß-D-Glc-Py-γ-Py-Ind (3; Glc=glucose), ß-D-Gal-Py-γ-Py-Ind (4; Gal=galactose), and the model compounds ß-D-Man-Py-NHAc (5) and ß-D-Tal-Py-NHAc (6) were synthesized and studied for comparison. We have demonstrated the existence of directional intramolecular hydrogen bonds in 1 and 2 in aqueous media. The unexpected differences in terms of stabilization of the intramolecular hydrogen bonds in 1 and 2 relative to 5 and 6 promoted us to evaluate the influence of CH-π interactions on the establishment of intramolecular hydrogen bonds by using computational methods. Initial binding studies of 1 and 2 with calf-thymus DNA and poly(dA-dT)2 by NMR spectroscopic analysis and molecular dynamics simulations were also carried out. Both new sugar-oligoamides are bound in the minor groove of DNA, thus keeping a stable hairpin structure, as in the free state, in which both intramolecular hydrogen-bonding and CH-π interactions are present.

Belizentrin, a highly bioactive macrocycle from the dinoflagellate Prorocentrum belizeanum.

Belizentrin (1), a novel 25-membered polyketide-derived macrocycle, was isolated from cultures of the marine dinoflagellate Prorocentrum belizeanum. This metabolite is the first member of an unprecedented class of polyunsaturated and polyhydroxylated macrolactams. The structure of 1 was primarily determined by NMR and computational methods. Pharmacological assays with cerebellar cells showed that 1 produces important changes in neuronal network integrity at nanomolar concentrations.

Na+/K+-ATPase inhibitor palytoxin enhances vulnerability of cultured cerebellar neurons to domoic acid via sodium-dependent mechanisms.

Dysfunction or deficiency of the Na(+)/K(+)-ATPase appears to be a common event in a variety of pathological conditions in the central nervous system. Studies on neurotoxicity associated to impaired Na(+)/K(+)-ATPase activity have focused on NMDA receptors, while the involvement of non-NMDA receptors has been much less explored. We show that mild, non-toxic, exposures to the Na(+)/K(+)-ATPase inhibitor palytoxin (PTX) synergistically sensitized the vulnerability of neurons to normally non-toxic concentrations of domoic acid, leaving NMDA receptor-mediated excitotoxic response unaltered. Enhancement of excitotoxicity required at least 1 h pre-exposure to PTX, was not observed after longer exposures to PTX, and did not require RNA synthesis. PTX caused a voltage-sensitive Na(+) channel-independent increase in intracellular Na(+). Both intracellular Na(+) increase and potentiation of excitotoxicity depended upon the external concentrations of Na(+) and Cl(-), and were suppressed by the anion exchanger blocker 4,4'-diisothiocyanatostilbene-2, 2'-disulfonic acid in a dose-dependent manner. Other stilbene derivatives, chloride channel antagonists or Na(+) cotransporter inhibitors proved ineffective. Our results demonstrate a crucial role for Na(+)/K(+)-ATPase activity in determining neuronal vulnerability to domoic acid-mediated excitotoxicity. They also raise reasonable concern about possible risks for human health associated to the ingestion of low amounts of phycotoxins PTX and domoic acid in food.