Reaching task performance is associated to neuromuscular junction adaptations in rats with induced diabetes mellitus.

Upper limb performance is affected by diabetes mellitus (DM). Neuromuscular junction (NMJ) is a key structure to understand the relationship between performance and morphology in DM. The aim of the study was to analyze NMJ plasticity due to DM in an animal model and its relationship with the function of forelimbs in rats. Twelve Wistar rats were divided into control (C) and DM groups. Animals were trained to perform a grasping task, following procedures of habituation, shaping, and reaching task. DM was induced using streptozotocin. Forelimb neuromuscular performance for dexterity was evaluated one day before DM induction and five weeks following induction. After that, biceps, triceps, and finger flexors and extensors were removed. Connective tissue and muscle fiber cross-sectional area (CSA) were measured. NMJ was assessed by its morphometric characteristics (area, perimeter, and maximum diameter), using ImageJ software. Motor performance analyses were made using single pellet retrieval task performance test. Student's t-test was used for comparisons between groups. A significant decrease in all NMJ morphometric parameters was observed in the DM group compared with the C group. Results showed that DM generated NMJ retraction in muscles involved in a reaching task. These alterations are related to signs of muscular atrophy and to poor reaching task performance. In conclusion, induced DM caused NMJ retraction and muscular atrophy in muscles involved in reaching task performance. Induced DM caused significantly lower motor performance, especially in the final moments of evaluation, when DM compromised the tropism of the muscular tissue.

Reaching task performance is associated to neuromuscular junction adaptations in rats with induced diabetes mellitus

Upper limb performance is affected by diabetes mellitus (DM). Neuromuscular junction (NMJ) is a key structure to understand the relationship between performance and morphology in DM. The aim of the study was to analyze NMJ plasticity due to DM in an animal model and its relationship with the function of forelimbs in rats. Twelve Wistar rats were divided into control (C) and DM groups. Animals were trained to perform a grasping task, following procedures of habituation, shaping, and reaching task. DM was induced using streptozotocin. Forelimb neuromuscular performance for dexterity was evaluated one day before DM induction and five weeks following induction. After that, biceps, triceps, and finger flexors and extensors were removed. Connective tissue and muscle fiber cross-sectional area (CSA) were measured. NMJ was assessed by its morphometric characteristics (area, perimeter, and maximum diameter), using ImageJ software. Motor performance analyses were made using single pellet retrieval task performance test. Student's t-test was used for comparisons between groups. A significant decrease in all NMJ morphometric parameters was observed in the DM group compared with the C group. Results showed that DM generated NMJ retraction in muscles involved in a reaching task. These alterations are related to signs of muscular atrophy and to poor reaching task performance. In conclusion, induced DM caused NMJ retraction and muscular atrophy in muscles involved in reaching task performance. Induced DM caused significantly lower motor performance, especially in the final moments of evaluation, when DM compromised the tropism of the muscular tissue.

Functional characterization of the Aspergillus nidulans glucosylceramide pathway reveals that LCB Δ8-desaturation and C9-methylation are relevant to filamentous growth, lipid raft localization and Psd1 defensin activity.

C8-desaturated and C9-methylated glucosylceramide (GlcCer) is a fungal-specific sphingolipid that plays an important role in the growth and virulence of many species. In this work, we investigated the contribution of Aspergillus nidulans sphingolipid Δ8-desaturase (SdeA), sphingolipid C9-methyltransferases (SmtA/SmtB) and glucosylceramide synthase (GcsA) to fungal phenotypes, sensitivity to Psd1 defensin and Galleria mellonella virulence. We showed that ΔsdeA accumulated C8-saturated and unmethylated GlcCer, while gcsA deletion impaired GlcCer synthesis. Although increased levels of unmethylated GlcCer were observed in smtA and smtB mutants, ΔsmtA and wild-type cells showed a similar 9,Me-GlcCer content, reduced by 50% in the smtB disruptant. The compromised 9,Me-GlcCer production in the ΔsmtB strain was not accompanied by reduced filamentation or defects in cell polarity. When combined with the smtA deletion, smtB repression significantly increased unmethylated GlcCer levels and compromised filamentous growth. Furthermore, sdeA and gcsA mutants displayed growth defects and raft mislocalization, which were accompanied by reduced neutral lipids levels and attenuated G. mellonella virulence in the ΔgcsA strain. Finally, ΔsdeA and ΔgcsA showed increased resistance to Psd1, suggesting that GlcCer synthesis and fungal sphingoid base structure specificities are relevant not only to differentiation but also to proper recognition by this antifungal defensin.

[Identifying gaps between guidelines and clinical practice in Clostridium difficile infection]. / Diferencias entre las recomendaciones y la práctica clínica en la infección por Clostridium difficile.

OBJECTIVES: The first aim was to determine whether patients are being treated in accordance with the Society for Healthcare Epidemiology of America and the Infectious Diseases Society of America (IDSA/SHEA) Clostridium difficile guidelines and whether adherence impacts patient outcomes. The second aim was to identify specific action items in the guidelines that are not being translated into clinical practice, for their subsequent implementation. MATERIAL AND METHODS: A retrospective, descriptive study was conducted over a 36 month period, on patients with compatible clinical symptoms and positive test for C. difficile toxins A and/or B in stool samples, in an internal medicine department of a tertiary medical centre. Patient demographic and clinical data (outcomes, comorbidity, risk factors) and compliance with guidelines, were examined RESULTS: A total of 77 patients with C. difficile infection were identified (87 episodes). Stratified by disease severity criteria, 49.3% of patients were mild-moderate, 35.1% severe, and 15.6% severe-complicated. Full adherence with the guidelines was observed in only 40.2% of patients, and was significantly better for mild-moderate (71.0%), than in severe (7.4%) or severe-complicated patients (16.6%) (P<.003). Adherence was significantly associated with clinical cure (57% vs 42%), fewer recurrences (22.2% vs 77.7%), and mortality (25% vs 75%) (P<.01). The stratification of severity of the episode, and the adequacy of antibiotic to clinical severity, need improvement. CONCLUSIONS: Overall adherence with the guidelines for management of Clostridium difficile infection was poor, especially in severe and severe-complicated patients, being associated with worse clinical outcomes. Educational interventions aimed at improving guideline adherence are warranted.

An analysis of spatial and socio-economic determinants of tuberculosis in Hermosillo, Mexico, 2000-2006.

SETTING: The city of Hermosillo, in Northwest Mexico, has a higher incidence of tuberculosis (TB) than the national average. However, the intra-urban TB distribution, which could limit the effectiveness of preventive strategies and control, is unknown. METHODS: Using geographic information systems (GIS) and spatial analysis, we characterized the geographical distribution of TB by basic geostatistical area (BGA), and compared it with a social deprivation index. Univariate and bivariate techniques were used to detect risk areas. RESULTS: Globally, TB in the city of Hermosillo is not spatially auto-correlated, but local clusters with high incidence and mortality rates were identified in the northwest, central-east and southwest sections of the city. BGAs with high social deprivation had an excess risk of TB. DISCUSSION: GIS and spatial analysis are useful tools to detect high TB risk areas in the city of Hermosillo. Such areas may be vulnerable due to low socio-economic status. The study of small geographical areas in urban settings similar to Hermosillo could indicate the best course of action to be taken for TB prevention and control.

Anti-homeostatic synaptic plasticity of glycine receptor function after chronic strychnine in developing cultured mouse spinal neurons.

In this study, we describe a novel form of anti-homeostatic plasticity produced after culturing spinal neurons with strychnine, but not bicuculline or 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX). Strychnine caused a large increase in network excitability, detected as spontaneous synaptic currents and calcium transients. The calcium transients were associated with action potential firing and activation of gamma-aminobutyric acid (GABA(A)) and alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptors as they were blocked by tetrodotoxin (TTX), bicuculline, and CNQX. After chronic blockade of glycine receptors (GlyRs), the frequency of synaptic transmission showed a significant enhancement demonstrating the phenomenon of anti-homeostatic plasticity. Spontaneous inhibitory glycinergic currents in treated cells showed a fourfold increase in frequency (from 0.55 to 2.4 Hz) and a 184% increase in average peak amplitude compared with control. Furthermore, the augmentation in excitability accelerated the decay time constant of miniature inhibitory post-synaptic currents. Strychnine caused an increase in GlyR current density, without changes in the apparent affinity. These findings support the idea of a post-synaptic action that partly explains the increase in synaptic transmission. This phenomenon of synaptic plasticity was blocked by TTX, an antibody against brain-derived neurotrophic factor (BDNF) and K252a suggesting the involvement of the neuronal activity-dependent BDNF-TrkB signaling pathway. These results show that the properties of GlyRs are regulated by the degree of neuronal activity in the developing network.

[Study on the immediate care clinics of the Internal Medicine Department (University Clinic Hospital of Valladolid)]. / Evaluación de las consultas de atención inmediata en Medicina Interna (Hospital Clínico Universitario de Valladolid).

BACKGROUND: Several studies have found a high percentage of inadequate admissions to Internal Medicine Departments. In order to try to alleviate this situation, the Immediate Care Clinics of the Internal Medicine Department (ICCIMD) was created, to study those patients who are suspected of having a serious disease, and whose physical condition allows them to undergo an out-patient study the day after having visited the Emergency Department. The tests requested will take precedence over the rest of the consultations. METHODS: Descriptive, retrospective study, through the review of the clinical records of the patients who came to the ICCIMD during the first two years. RESULTS: Our service admitted 726 people in the ACCIMD, 52.2 % males, average age of 54.12 years old. A total of 18.6 % of the patients required hospital admission; this admission being carried out at the first medical examination in 66.7% of the cases. In most cases, it can be related with shortening a study that would have lasted longer. In spite of this, we consider that 1.4 daily admissions have been avoided. Mean time devoted to this study was about 33.20 days, much greater than that expected, because of the high prevalence of non-specific disease and hospital organization deficit. It was decided to study 76.6% of the patients sent, their diagnosis being achieved in 63.3% of the total number of patients. Nevertheless, the ICCIMD was inadequate, as hospital admission was required or the patient was sent to other specialities in the 27.3% of the cases. CONCLUSIONS: We think that the ACCIMD can be useful to improve efficiency of Internal Medicine Department, although, to do so, the significant problems found must be solved.

Evaluación de las consultas de atención inmediata en Medicina Interna (Hospital Clínico Universitario de Valladolid) / Study on the inmediate care clinics of the Internal Medicine Department (Universitary Clinic Hospital of Valladolid)

Introducción. Diversos estudios han encontrado un alto porcentaje de ingresos inadecuados en los servicios de Medicina Interna. Para paliar esta situación se creó la Consulta de Atención Inmediata en Medicina Interna (CAIMI), en la que se estudia a pacientes con sospecha de patología grave, pero que su estado físico les permita un estudio ambulatorio al día siguiente de haber ido a Urgencias. Las pruebas solicitadas tendrían prioridad sobre las del resto de consultas. Métodos. Estudio descriptivo, retrospectivo, mediante la revisión de las historias clínicas de los pacientes atendidos en la CAIMI durante los dos primeros años. Resultados. Nuestro servicio atendió en la CAIMI a 726 personas (el 52,2% varones) con una edad media de 54,12 años. El 18,6% de los pacientes atendidos precisó el ingreso; el 66,7% de ellos desde la primera consulta. En la mayoría de los casos parece relacionarse con el hecho de acortar un estudio que se prevé largo. A pesar de ello estimamos que se han evitado 1,4 ingresos al día. El tiempo medio de estudio empleado fue de 33,20 días, muy superior al esperado, debido a la alta prevalencia de patología inespecífica valorada y déficit de organización hospitalaria. Se decidió estudiar al 76,6% de los pacientes enviados, lográndose el diagnóstico en el 63,3% del total de pacientes. Sin embargo, la CAIMI fue insuficiente al precisar el ingreso o la derivación a otras especialidades en el 27,3% de los casos. Conclusiones. Creemos que la CAIMI puede ser útil para mejorar la eficiencia de los servicios de Medicina Interna, aunque para ello es necesario solucionar los importantes déficit encontrados

Background. Several studies have found a high percentage of inadequate admissions to Internal Medicine Departments. In order to try to alleviate this situation, the Immediate Care Clinics of the Internal Medicine Department (ICCIMD) was created, to study those patients who are suspected of having a serious disease, and whose physical condition allows them to undergo an out-patient study the day after having visited the Emergency Department. The tests requested will take precedence over the rest of the consultations. Methods. Descriptive, retrospective study, through the review of the clinical records of the patients who came to the ICCIMD during the first two years. Results. Our service admitted 726 people in the ACCIMD, 52.2 % males, average age of 54.12 years old. A total of 18.6 % of the patients required hospital admission; this admission being carried out at the first medical examination in 66.7% of the cases. In most cases, it can be related with shortening a study that would have lasted longer. In spite of this, we consider that 1.4 daily admissions have been avoided. Mean time devoted to this study was about 33.20 days, much greater than that expected, because of the high prevalence of non-specific disease and hospital organization deficit. It was decided to study 76.6% of the patients sent, their diagnosis being achieved in 63.3% of the total number of patients. Nevertheless, the ICCIMD was inadequate, as hospital admission was required or the patient was sent to other specialities in the 27.3% of the cases. Conclusions. We think that the ACCIMD can be useful to improve efficiency of Internal Medicine Department, although, to do so, the significant problems found must be solved

Pentylenetetrazole induced changes in zebrafish behavior, neural activity and c-fos expression.

Rodent seizure models have significantly contributed to our basic understanding of epilepsy. However, medically intractable forms of epilepsy persist and the fundamental mechanisms underlying this disease remain unclear. Here we show that seizures can be elicited in a simple vertebrate system e.g. zebrafish larvae (Danio rerio). Exposure to a common convulsant agent (pentylenetetrazole, PTZ) induced a stereotyped and concentration-dependent sequence of behavioral changes culminating in clonus-like convulsions. Extracellular recordings from fish optic tectum revealed ictal and interictal-like electrographic discharges after application of PTZ, which could be blocked by tetrodotoxin or glutamate receptor antagonists. Epileptiform discharges were suppressed by commonly used antiepileptic drugs, valproate and diazepam, in a concentration-dependent manner. Up-regulation of c-fos expression was also observed in CNS structures of zebrafish exposed to PTZ. Taken together, these results demonstrate that chemically-induced seizures in zebrafish exhibit behavioral, electrographic, and molecular changes that would be expected from a rodent seizure model. Therefore, zebrafish larvae represent a powerful new system to study the underlying basis of seizure generation, epilepsy and epileptogenesis.

Hippocampal heterotopia with molecular and electrophysiological properties of neocortical neurons.

Cortical malformations resulting from aberrant brain development can be associated with mental retardation, dyslexia, and intractable forms of epilepsy. Despite emerging interest in the pathology and etiology of cortical malformations, little is known about the phenotype of cells within these lesions. In utero exposure to the DNA methylating agent methylazoxymethanol acetate (MAM) during a critical stage in neurodevelopment results in animals with distinct clusters of displaced neurons in hippocampus, i.e. nodular heterotopia. Here we examined the molecular and electrophysiological properties of cells within hippocampal heterotopia using rats exposed to MAM during gestation. Molecular analysis revealed that heterotopic cells do not express mRNA markers normally found in hippocampal pyramidal cells or dentate granule cells (SCIP, Math-2, Prox-1, neuropilin-2). In contrast, Id-2 mRNA, normally abundant in Layer II-III supragranular neocortical neurons but not in CA1 pyramidal neurons, was prominently expressed in hippocampal heterotopia. Current-clamp analysis of the firing properties of heterotopic neurons revealed a striking similarity with supragranular cortical neurons. In particular, both cells were characterized by small hyperpolarizing 'sag' potentials, high input resistance values, slow spike-train afterhyperpolarizations, and the absence of a depolarizing afterpotential. Normotopic CA1 pyramidal neurons (e.g. pyramidal cells with normal lamination adjacent to a heterotopia) in the MAM brain exhibited molecular and electrophysiological properties that were nearly identical to those of age-matched CA1 pyramidal neurons from control rats. We conclude that neuronal heterotopiae in the hippocampus of MAM-exposed rats are comprised of neurons with a Layer II-III supragranular cortex phenotype. The MAM model, therefore, may serve as a useful tool in examination of the factors influencing aberrant brain development and epilepsy.

Hippocampal heterotopia lack functional Kv4.2 potassium channels in the methylazoxymethanol model of cortical malformations and epilepsy.

Human cortical malformations often result in severe forms of epilepsy. Although the morphological properties of cells within these malformations are well characterized, very little is known about the function of these cells. In rats, prenatal methylazoxymethanol (MAM) exposure produces distinct nodules of disorganized pyramidal-like neurons (e.g., nodular heterotopia) and loss of lamination in cortical and hippocampal structures. Hippocampal nodular heterotopias are prone to hyperexcitability and may contribute to the increased seizure susceptibility observed in these animals. Here we demonstrate that heterotopic pyramidal neurons in the hippocampus fail to express a potassium channel subunit corresponding to the fast, transient A-type current. In situ hybridization and immunohistochemical analysis revealed markedly reduced expression of Kv4.2 (A-type) channel subunits in heterotopic cell regions of the hippocampus of MAM-exposed rats. Patch-clamp recordings from visualized heterotopic neurons indicated a lack of fast, transient (I(A))-type potassium current and hyperexcitable firing. A-type currents were observed on normotopic pyramidal neurons in MAM-exposed rats and on interneurons, CA1 pyramidal neurons, and cortical layer V-VI pyramidal neurons in saline-treated control rats. Changes in A-current were not associated with an alteration in the function or expression of delayed, rectifier (Kv2.1) potassium channels on heterotopic cells. We conclude that heterotopic neurons lack functional A-type Kv4.2 potassium channels and that this abnormality could contribute to the increased excitability and decreased seizure thresholds associated with brain malformations in MAM-exposed rats.

Hippocampal dysplasia in rats exposed to cocaine in utero.

Prenatal cocaine exposure can result in neurobehavioral disturbances and structural modifications of the central nervous system. In the present study, cocaine was injected into pregnant rats and the brains of their offspring were examined at the light microscopic level. As adults, cocaine-exposed offspring exhibited subtle, but consistent, hippocampal abnormalities. In particular, the stratum pyramidale (particularly the CA1 region) was interrupted by frequent gaps in lamination, and ectopic pyramidal cells were found in stratum oriens and radiatum.

Micellar shape anisotropy and elastic constants in discotic lyotropic liquid crystals.

The elastic constants of a discotic lyotropic nematic liquid crystal are calculated by means of a pseudomolecular approach as functions of the micellar shape anisotropy. By assuming that the temperature dependence of the ratio of the elastic constants comes from the temperature dependence of the micellar shape anisotropy, the theoretical predictions are connected with experimental measurements for the ratio K(33)/K(11). This procedure permits one to determine, in a phenomenological way, the temperature dependence for the ratio of elastic constants and for the micellar shape anisotropy near the nematic-isotropic transition in agreement with the experimental data.