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.

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.

[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.

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).

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.

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.

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.

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.

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.

Blood pressure reduction in hypertensive patients after withdrawal of effervescent medication.

BACKGROUND: Raised blood pressure associated with the sodium excipient content of soluble or effervescent analgesic has been previously reported. However, the influence of other anions associated with sodium on blood pressure is still controversial. METHODS: Observational study of elderly hypertensive patients with uncontrolled blood pressure treated with effervescent paracetamol (3 g/day) for osteoarthritis. Blood pressure was measured before and after (4 weeks or more) switching paracetamol from an effervescent format to a tablet form in 34 patients. Blood pressure was recorded by community pharmacists during a pharmacotherapeutic follow-up service. RESULTS: Sodium intake in an effervescent form was 74 mmol/day (mainly associated with sodium bicarbonate and carbonate excipients). Initial blood pressure was high (range: 153-168 mmHg systolic and 92-99 mmHg diastolic). Switching to paracetamol tablets (no sodium content) was associated with both lowered systolic pressure of 13.1 mmHg (95%CI: 11.9-14.3, p < 0.0001) and a moderate reduction of diastolic pressure of 2.5 mmHg (95%CI: 2.1-2.9, p < 0.0001). No changes in medication in the study period took place, and weight and lifestyles remained stable. A detailed review of pharmacotherapy and lifestyle reveals no other causes for blood pressure to lower. CONCLUSIONS: A relationship of causality between the intake of high sodium excipients and high blood pressure in elderly hypertensive individuals, without chloride ions, was found. Clinicians should be aware of possible raised blood pressure when effervescent formulations are prescribed to hypertensive patients.

Inhibition of protein phosphatases impairs the ability of astrocytes to detoxify hydrogen peroxide.

We have used protein phosphatase (PP) inhibitors and rat cerebellar glial cells in primary culture to investigate the role of PP activity in the ability of glial cells to detoxify exogenously applied hydrogen peroxide (H2O2). The marine toxin okadaic acid (OKA), a potent PP1 and PP2A inhibitor, caused a concentration-dependent degeneration of astrocytes and increased the formation of hydroperoxide radicals significantly. Subtoxic exposures to OKA significantly potentiated toxicity by exogenous H2O2. The concentration of H2O2 that reduced by 50% the survival of astrocytes after 3 h was estimated at 720+/-40 microM in the absence and 85+/-30 microM in the presence of the toxin. The PP inhibitors calyculin A and endothall also potentiated H2O2 toxicity in cerebellar astrocytes. OKA caused a time-dependent inhibition of both glial catalase and glutathione peroxidase, reducing by approximately 50% the activity of these enzymes after 3 h, whereas other enzymatic activities remained unaffected. Also, OKA reduced the cellular content of total glutathione and elevated oxidized glutathione to about 25% of total glutathione. OKA-treated astrocytes cleared H2O2 from the incubation medium approximately two times more slowly than control cultures. Our results suggest a prominent role for PP activity in the antioxidant mechanisms protecting astrocytes against damage by H2O2.

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.

Potent neurotoxic action of the shellfish biotoxin yessotoxin on cultured cerebellar neurons.

Yessotoxin (YTX) and its analogues are disulphated polyether compounds of increasing occurrence in seafood. The biological effects of these algal toxins on mammals and the risk associated to their ingestion have not been clearly established. We have used primary cultures of rat cerebellar neurons to investigate whether YTX affected survival and functioning of central nervous system neurons. Exposure to YTX (> or =25 nM) caused first (approximately 8 h) weakening, granulation, and fragmentation of neuronal network, and later (approximately 48 h) complete disintegration of neurites and extensive neuronal death, with a significant decrease in the amount of filamentous actin. The concentration of YTX that reduced by 50% the maximum neuronal survival (EC50(48)) was approximately 20 nM. Lower toxin concentrations (approximately 15 nM) also caused visible signs of toxicity affecting neuronal network primarily. Removal of YTX after 5 h exposure delayed the onset of neurotoxicity but did not prevent neuronal degeneration and death. YTX induced a two-fold increase in cytosolic calcium that was prevented by the voltage-sensitive calcium channel antagonists nifedipine and verapamil. These antagonists were, however, completely ineffective in reducing neurotoxicity. Voltage-sensitive sodium channel antagonists saxitoxin and nefopam, and the NMDA receptor antagonist MK-801 also failed to prevent YTX neurotoxicity. Neuronal death by YTX involved typical hallmarks of apoptosis and required the synthesis of new proteins. Our data suggest neuronal tissue to be a vulnerable biological target for YTX. The potent neurotoxicity of YTX we report raises reasonable concern about the potential risk that exposure to YTX may represent for neuronal survival in vivo.

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.

Free radicals and antioxidant systems in reflux esophagitis and Barrett's esophagus.

AIM: Experimental studies suggest that free radicals are involved in acid and pepsin-induced damage of esophageal mucosa. The profile and balance between free radicals and antioxidant systems in human esophagitis are unknown. METHODS: Superoxide anion and its powerful oxidant reaction with nitric oxide (peroxynitrite) generation were determined in esophageal mucosal biopsies from 101 patients with different gastro-esophageal reflux diseases and 28 controls. Activity of both superoxide dismutase (SOD) and catalase, and reduced glutathione (GSH) levels, were also assessed. Expression of Cu, ZnSOD, MnSOD and tyrosine-nitrated MnSOD were analyzed by Western blot and/or immunohistochemistry. RESULTS: The highest levels of superoxide anion generation were found in patients with severe lesions of esophagitis. Peroxynitrite generation was intense in Barrett's biopsies, weaker in esophagitis and absent/weak in normal mucosa. Expression of Cu, ZnSOD and MnSOD isoforms were present in normal mucosa and increased according to the severity of the lesion, reaching the highest level in Barrett's esophagus. However, SOD mucosal activity significantly decreased in patients with esophagitis and Barrett's esophagus, which was, at least in part, due to nitration of its tyrosine residues. Catalase activity and GSH levels were significantly increased in mucosal specimens from patients with esophagitis and/or Barrett's esophagus. CONCLUSION: A decrease in SOD antioxidant activity leading to increased mucosal levels of superoxide anion and peroxynitrite radicals may contribute to the development of esophageal damage and Barrett's esophagus in patients with gastroesophageal reflux. Administration of SOD may be a therapeutic target in the treatment of patients with esophagitis and Barrett's esophagus.

The marine toxin dinophysistoxin-2 induces differential apoptotic death of rat cerebellar neurons and astrocytes.

Diarrhetic shellfish poisoning (DSP) toxins of algal origin are frequent contaminants of coastal waters and seafood. The potential risk for human health due to the continuous presence of these toxins in food has not been clearly established. We have used cerebellar primary cultures to investigate the effects of the DSP toxin dinophysistoxin-2 (DTX-2) on central nervous system neurons and glial cells. Exposure to DTX-2 produced neurotoxicity at concentrations starting at 2.5 nM, characterized first by disintegration of neurites and later by cell death. DTX-2-induced neurodegeneration required long exposures (at least 20 h), involved DNA fragmentation and condensation and fragmentation of chromatin, typical hallmarks of apoptosis, and required the synthesis of new proteins. The concentration that reduced by 50% the maximum neuronal survival after 24 h exposure to DTX-2 (EC50(24)) was approximately 8 nM. Morphology and viability of glial cells remained unaffected up to at least 15 nM DTX-2. Higher concentrations of the toxin caused strong shrinkage of glial cell bodies and retraction of processes, and a significant reduction of glial cell viability. Glial toxicity by DTX-2 involved typical apoptotic condensation and fragmentation of chromatin. Compared to neurons, the effect on glial cells was a much shorter process, and extensive glial degeneration and death occurred after 7 h exposure to DTX-2 (EC50(7) approximately 50 nM; EC50(24) approximately 30 nM). Although further experiments are needed to confirm these toxic actions in vivo, our in vitro data suggest that chronic exposure to amounts of DSP toxins below the current safety regulatory limits may represent a risk for human health that should be taken into consideration.

RNA synthesis-dependent potentiation of alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionate receptor-mediated toxicity by antihistamine terfenadine in cultured rat cerebellar neurons.

We have studied the effects of terfenadine on neurotoxicity and elevation of free cytoplasmic Ca2+ levels upon stimulation of alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionate (AMPA) receptors in cultured cerebellar neurons. Pre-exposure to terfenadine (5 microM, 5 h) significantly increased neuronal death following specific stimulation of receptors by 100 microM AMPA or by subtoxic concentrations of domoate (8 microM), stimuli that are non-toxic when applied to terfenadine-untreated sister cultures. Terfenadine potentiation was prevented by the transcription inhibitor actinomycin D and was significantly ameliorated by histamine (1 mM). In terfenadine-treated neurons, AMPA increased [Ca2+](i) by approximately five fold, while AMPA induced no significant increase in [Ca2+](i) in the absence of terfenadine. Terfenadine reduced neuronal steady-state concentrations of [Ca2+](i) by approximately 75%. Our results suggest a role for histamine H1 receptors and intracellular calcium in the modulation of the excitotoxic response via AMPA receptors.