A Clinical Trial Comparing Smoking Cessation Interventions at Two Levels of Intensity in Stroke Patients, Stratified by the Presence of Insular Cortex Lesions.

INTRODUCTION: Smoking is a stroke risk factor but the most efficient way to promote cessation is unknown. The smoking behavior in patients during the first 2 years post-stroke is studied comparing brief advice and intensive behavioral counseling interventions, taking into consideration biological, psychological, and social factors. METHODS: Randomized clinical trial of 196 stroke patients, stratified by the presence or not of an insular cortex lesion, with two levels of smoking cessation intervention. RESULTS: The study retention rate was 85.2%. Abstinence point prevalence at three months after stroke was 50% in the brief advice group and 51.7% in the intensive behavioral counseling group (p = .82) and at 24 months, 48.3% in the brief group and 47.5% in the intensive group (p = .92). Most relapses occurred in the first weeks. After 3 months the curves separated with fewer events in the intensive group and at 24 months the Hazard Ratio was 0.91 (95% CI = 0.61 to 1.37; p = .67). Twenty-four months after stroke, patients with an insular lesion were more likely to be abstinent (OR 3.60, 95% CI = 1.27 to 10.14), as were those who lived with a partner (OR 2.31, 95% CI = 1.17 to 4.55) and those who were less dependent (OR 0.84, 95% CI = 0.73 to 0.97). CONCLUSIONS: A high percentage of patients gave up smoking in both intervention groups with no significant differences between the two. The effect of the insular lesion on smoking cessation, which is early and continued after two years, is particularly notable. IMPLICATIONS: This two-year clinical trial compares for the first time the efficacy of two different intensities of smoking cessation intervention in stroke patients, taking into consideration the effect of the insula. Good results are obtained both in the short and medium-term in people with stroke, especially when this is accompanied by an insular cortex lesion, but there is no evidence that better results are obtained with longer, more time-intensive, and possibly more costly follow-ups obtain better results than are obtained with briefer interventions.

Tubulointerstitial nephritis and uveitis syndrome in children: report of three cases / Nefrite tubulointersticial e uveíte em idade pediátrica: descrição de três doentes

ABSTRACT Tubulointerstitial nephritis and uveitis syndrome is a rare and probably underdiagnosed condition. Renal and ocular manifestations may not occur simultaneously, making the diagnosis more difficult. Nephritis may be asymptomatic; therefore, renal function evaluation is essential for diagnosis. Urinary β2-microglobulin levels may be particularly useful. Uveitis, mostly anterior, nongranulomatous and bilateral, occurs usually after the onset of nephritis. Treatment includes corticosteroids and, eventually, other immunosuppressant agents. Renal disease is usually benign and resolves spontaneously or after treatment with systemic corticosteroids. Uveitis, however, may be chronic or recurrent. The authors described the cases of three pediatric patients diagnosed with tubulointerstitial nephritis and uveitis syndrome. The goal of this paper was to warn the medical community over the need to screen patients with uveitis for renal disease.

RESUMO A síndrome nefrite tubulointersticial e uveíte é uma doença rara, provavelmente subdiagnosticada. As manifestações renais e oculares podem não ocorrer simultaneamente, tornando o diagnóstico mais difícil. A nefrite é geralmente assintomática, tornando fundamental a avaliação da função renal em doentes com uveíte. O doseamento da excreção urinária de β2-microglobulina é particularmente útil para o diagnóstico. A uveíte, tipicamente anterior, não granulomatosa e bilateral, manifesta-se após a nefrite na maioria dos casos. O tratamento inclui corticoides e, por vezes, outros imunossupressores. A doença renal tem evolução benigna, resolvendo-se espontaneamente ou com terapêutica com corticoides sistêmicos na maioria dos casos, no entanto, a uveíte pode ser crônica ou recorrente. Os autores descrevem três casos de síndrome nefrite tubulointersticial e uveíte, diagnosticados em idade pediátrica, e pretendem alertar para a necessidade de pesquisar sempre alterações renais nos doentes com uveíte.

Tubulointerstitial nephritis and uveitis syndrome in children: report of three cases.

Tubulointerstitial nephritis and uveitis syndrome is a rare and probably underdiagnosed condition. Renal and ocular manifestations may not occur simultaneously, making the diagnosis more difficult. Nephritis may be asymptomatic; therefore, renal function evaluation is essential for diagnosis. Urinary ß2-microglobulin levels may be particularly useful. Uveitis, mostly anterior, nongranulomatous and bilateral, occurs usually after the onset of nephritis. Treatment includes corticosteroids and, eventually, other immunosuppressant agents. Renal disease is usually benign and resolves spontaneously or after treatment with systemic corticosteroids. Uveitis, however, may be chronic or recurrent. The authors described the cases of three pediatric patients diagnosed with tubulointerstitial nephritis and uveitis syndrome. The goal of this paper was to warn the medical community over the need to screen patients with uveitis for renal disease.

Caracterización de los procedimientos para la realización de hemocultivos en pacientes adultos, en instituciones hospitalarias del Área Metropolitana del Valle de Aburrá / Characterization of procedures for performing blood cultures in adult patients, in hospitals of the Metropolitan Area of Aburrá Valley

Objetivo: Caracterizar procedimientos para la toma, análisis, reporte y aseguramiento de la calidad en hemocultivos en pacientes adultos, en instituciones hospitalarias. Material Y método: Estudio descriptivo en 15 Hospitales de Medellín y alrededores. Se empleó un formulario semiestructurado para recolectarla información, se utilizó SPSS(r) para el análisis. Resultados: Todas las instituciones tienen protocolos basados en fuentes de autoridad reconocida; con diferencias importantes en procesos pre-analíticos y postanalíticos. Los Productos más empleados para la antisepsia fueron gluconato declorhexidina al 2-4%(66,7%) Y alcohol isopropílico o etílico al 70% (20,0%),Con discrepancias en los tiempos de acción. El 73,3% emplea guantes estériles y la misma proporción usa sistema abierto (jeringa) para la venopunción. En el 46,6% se toman dos botellas aerobias y una anaerobia por episodio y en 33,3% dos botellas aerobias. El 66,6% lleva un indicador de contaminación, 53,3% de positividad y 26,6% de volumen de sangre. La tasa promedio de hemocultivos contaminados durante el semestre de seguimiento fue 1,61%. Conclusión: Se observa heterogeneidad en los procedimientos, especialmente en fases pre-analítica y post-analítica. En La búsqueda de la excelencia y la seguridad del paciente son necesarios protocolos estandarizados e indicadores para medir y controlar el desempeño de los hemocultivos.

Objective: To characterize the procedures that are performed for the collection, analysis, reporting and quality assurance of blood cultures in adult patients in hospital institutions. Material and Methods: Descriptive study in 15 hospitals of Medellin and its surroundings. A semi-structured collection instrument was used to collect the information provided by each hospital; SPSS(r) was used for the analysis. Results: All Institutions have protocols based o nauthorized sources; there were important differences in the pre-analytic and post-analytic processes. The Products employed for skin antisepsis were2-4% Chlorhexidine gluconate (66.7%)And70% Isopropyl or ethyl alcohol(20.0%), with discrepancies in product action times. 73.3% use sterile gloves and an equal proportion uses an open system (syringe) for venipuncture. Two aerobic and one anaerobic bottles are taken per episode in adult patients in 46.6% of institutions and only two aerobic bottles in 33.3% of them. Indicators of contamination were used by 66.6 % of institutions, of positivity in 53.3% and of blood volume in 26.6%. The average rate of contaminated blood cultures during the follow-up period was 1.61%. Conclusion: Heterogeneity in the procedures was observed especially in the pre-analytic and post-analytical phases. In the pursuit of excellence and patient safety, standardized protocols and the use of indicators to measure and control the performance of blood cultures are needed.

Relevancia a corto plazo de la coinfección viral en pacientes menores de 2 años hospitalizados con infecciones de las vías respiratorias inferiores / Short-term relevance of lower respiratory viral coinfection in inpatients under 2 years of age

Introducción: Avances en el diagnóstico molecular han hecho posible la detección de agentes virales desconocidos en infecciones de las vías respiratorias inferiores (IVRI). Sin embargo, sigue habiendo dudas relativamente a su frecuencia y relevancia. Objetivo: Comparar la clínica y la gravedad entre la infección por virus único y la coinfección en niños admitidos por IVRI. Métodos: Se realizó un estudio durante 3 años consecutivos (2012-2015) que incluyó a niños menores de 2 años ingresados por IVRI. La identificación viral se realizó mediante la técnica de PCR para 16 virus. Los datos clínicos y el uso de los recursos hospitalarios se recogieron de forma estándar durante la estancia hospitalaria y se compararon la infección única con coinfecciones virales. Resultados: Fueron analizadas 524 muestras (451 pacientes); 448 (85,5%) tuvieron al menos un virus identificado. Coinfecciones virales se encontraron en 159 (35,5%). RSV y HRV fueron los virus más frecuentes; bronquiolitis y neumonía, los diagnósticos principales. Los pacientes con coinfecciones virales eran mayores, iban a la guardería, tenían sibilancias recurrentes con más frecuencia y eran más sintomáticos al ingreso. No fueron sometidos a más exámenes, pero les fueron prescritos medicamentos con más frecuencia. El grupo de la coinfección viral no mostró una mayor duración de la estancia hospitalaria, de la necesidad de oxígeno, de UCI o soporte ventilatorio. Discusión: Nuestro estudio mostró una proporción significativa de coinfecciones virales en los niños pequeños ingresados con IVRI y confirma dados previos que muestran que la prescripción es más frecuente en las coinfecciones virales, sin asociación con peor resultado clínico (AU)

Introduction: Advances in molecular diagnosis have made it possible to detect previously unknown viral agents as causative agents of lower respiratory tract infections (LRTI). The frequency and relevance of viral coinfections is still debatable. Objective: compare clinical presentation and severity between single virus infection and viral coinfection in children admitted for LRTI. Methods: A 3-year period observational study (2012-2015) included children younger than two years admitted for LRTI. Viral identification was performed using PCR technique for 16 viruses. Clinical data and use of health resources was gathered during hospital stay using a standard collection form and we compared single virus infection and viral coinfections. Results: The study included 524 samples (451 patients); 448 (85,5%) had at least one virus identified. Viral coinfections were found in 159 (35,5%). RSV and HRV were the most commonly identified virus; bronchiolitis and pneumonia the most frequent diagnosis. Patients with viral coinfections were older, attended day-care centers, had previous recurrent wheezing more frequently and were more symptomatic at admission. These patients did not have more complementary exams performed but were prescribed medications more often. Viral coinfection group did not show longer length of hospital stay and oxygen need, more need for ICU nor ventilatory support. Discussion: Our study showed a significant proportion of viral coinfections in young infants admitted with LRTI and confirmed previous data showing that prescription was more frequent in inpatients with viral coinfections, without an association with worst clinical outcome (AU)

[Short-term relevance of lower respiratory viral coinfection in inpatients under 2 years of age]. / Relevancia a corto plazo de la coinfección viral en pacientes menores de 2 años hospitalizados con infecciones de las vías respiratorias inferiores.

INTRODUCTION: Advances in molecular diagnosis have made it possible to detect previously unknown viral agents as causative agents of lower respiratory tract infections (LRTI). The frequency and relevance of viral coinfections is still debatable. OBJECTIVE: compare clinical presentation and severity between single virus infection and viral coinfection in children admitted for LRTI. METHODS: A 3-year period observational study (2012-2015) included children younger than two years admitted for LRTI. Viral identification was performed using PCR technique for 16 viruses. Clinical data and use of health resources was gathered during hospital stay using a standard collection form and we compared single virus infection and viral coinfections. RESULTS: The study included 524 samples (451 patients); 448 (85,5%) had at least one virus identified. Viral coinfections were found in 159 (35,5%). RSV and HRV were the most commonly identified virus; bronchiolitis and pneumonia the most frequent diagnosis. Patients with viral coinfections were older, attended day-care centers, had previous recurrent wheezing more frequently and were more symptomatic at admission. These patients did not have more complementary exams performed but were prescribed medications more often. Viral coinfection group did not show longer length of hospital stay and oxygen need, more need for ICU nor ventilatory support. DISCUSSION: Our study showed a significant proportion of viral coinfections in young infants admitted with LRTI and confirmed previous data showing that prescription was more frequent in inpatients with viral coinfections, without an association with worst clinical outcome.

Short-term relevance of lower respiratory viral coinfection in inpatients under 2 years of age.

INTRODUCTION: Advances in molecular diagnosis have made it possible to detect previously unknown viral agents as causative agents of lower respiratory tract infections (LRTI). The frequency and relevance of viral coinfections is still debatable. OBJECTIVE: Compare clinical presentation and severity between single virus infection and viral coinfection in children admitted for LRTI. METHODS: A 3-year period observational study (2012-2015) included children younger than two years admitted for LRTI. Viral identification was performed using PCR technique for 16 viruses. Clinical data and use of health resources was gathered during hospital stay using a standard collection form and we compared single virus infection and viral coinfections. RESULTS: The study included 524 samples (451 patients); 448 (85.5%) had at least one virus identified. Viral coinfections were found in 159 (35.5%). RSV and HRV were the most commonly identified virus; bronchiolitis and pneumonia the most frequent diagnosis. Patients with viral coinfections were older, attended day-care centers, had previous recurrent wheezing more frequently and were more symptomatic at admission. These patients did not have more complementary exams performed but were prescribed medications more often. Viral coinfection group did not show longer length of hospital stay and oxygen need, more need for ICU nor ventilatory support. DISCUSSION: Our study showed a significant proportion of viral coinfections in young infants admitted with LRTI and confirmed previous data showing that prescription was more frequent in inpatients with viral coinfections, without an association with worst clinical outcome.

INTRODUCCIÓN: Avances en el diagnóstico molecular han hecho posible la detección de agentes virales desconocidos en infecciones de las vías respiratorias inferiores (IVRI). Sin embargo, sigue habiendo dudas relativamente a su frecuencia y relevancia. OBJETIVO: Comparar la clínica y la gravedad entre la infección por virus único y la coinfección en niños admitidos por IVRI. MÉTODOS: Se realizó un estudio durante 3 años consecutivos (2012-2015) que incluyó a niños menores de 2 años ingresados por IVRI. La identificación viral se realizó mediante la técnica de PCR para 16 virus. Los datos clínicos y el uso de los recursos hospitalarios se recogieron de forma estándar durante la estancia hospitalaria y se compararon la infección única con coinfecciones virales. RESULTADOS: Fueron analizadas 524 muestras (451 pacientes); 448 (85,5%) tuvieron al menos un virus identificado. Coinfecciones virales se encontraron en 159 (35,5%). RSV y HRV fueron los virus más frecuentes; bronquiolitis y neumonía, los diagnósticos principales. Los pacientes con coinfecciones virales eran mayores, iban a la guardería, tenían sibilancias recurrentes con más frecuencia y eran más sintomáticos al ingreso. No fueron sometidos a más exámenes, pero les fueron prescritos medicamentos con más frecuencia. El grupo de la coinfección viral no mostró una mayor duración de la estancia hospitalaria, de la necesidad de oxígeno, de UCI o soporte ventilatorio. DISCUSIÓN: Nuestro estudio mostró una proporción significativa de coinfecciones virales en los niños pequeños ingresados con IVRI y confirma dados previos que muestran que la prescripción es más frecuente en las coinfecciones virales, sin asociación con peor resultado clínico.

Arginine deiminase pathway genes and arginine degradation variability in Oenococcus oeni strains.

Trace amounts of the carcinogenic ethyl carbamate can appear in wine as a result of a reaction between ethanol and citrulline, which is produced from arginine degradation by some bacteria used in winemaking. In this study, arginine deiminase (ADI) pathway genes were evaluated in 44 Oenococcus oeni strains from wines originating from several locations in order to establish the relationship between the ability of a strain to degrade arginine and the presence of related genes. To detect the presence of arc genes of the ADI pathway in O. oeni, pairs of primers were designed to amplify arcA, arcB, arcC and arcD1 sequences. All strains contained these four genes. The same primers were used to confirm the organization of these genes in an arcABCD1 operon. Nevertheless, considerable variability in the ability to degrade arginine among these O. oeni strains was observed. Therefore, despite the presence of the arc genes in all strains, the expression patterns of individual genes must be strain dependent and influenced by the different wine conditions. Additionally, the presence of arc genes was also determined in the 57 sequenced strains of O. oeni available in GenBank, and the complete operon was found in 83% of strains derived from wine. The other strains were found to lack the arcB, arcC and arcD genes, but all contained sequences homologous to arcA, and some of them had also ADI activity.

Ready-to-eat street-vended food as a potential vehicle of bacterial pathogens and antimicrobial resistance: An exploratory study in Porto region, Portugal.

The ready-to-eat street vending commerce, as street mobile food vendors, has grown exponentially worldwide, representing in some countries a significant proportion of food consumed by the urban population. However, the microbiological food safety hazards of mobile vending units in industrialized countries are scarcely evaluated. To assess the microbiological quality and safety of this type of food and try to achieve the connection of its contamination with hygienic conditions of food-handlers, we analyzed hotdogs (n = 10), hamburgers (n = 10) and hands (n = 9) from ten street-vending trailers in the Porto region. Food and food-handler samples were tested for Enterobacteriaceae and coliform counts, Escherichia coli and coagulase-positive staphylococci counts/detection and presence of Salmonella. Aerobic mesophilic counts and detection of Listeria monocytogenes (Pulsed Field Gel Electrophoresis-PFGE and serotyping) were also tested in food samples. E. coli isolates were confirmed by MALDI-TOF and characterized for clonality (phylogenetic groups-PhG, PFGE and Multilocus Sequence Typing), antibiotic resistance (disk diffusion, PCR/sequencing) and intestinal pathogenic virulence factors (PCR/sequencing). All food samples presented poor microbiological quality (100% Enterobacteriaceae and coliforms; 20% E. coli (4 hamburgers, 4 trailers) and 20% (2 hamburgers/2 hotdogs, 3 trailers) were positive for L. monocytogenes (2 PFGE-types belonging to serotype 1/2a and 4b). Salmonella and coagulase-positive staphylococci were not detected. Food-handlers carried Enterobacteriaceae and coliforms (100%), E. coli (11%) and/or coagulase-positive staphylococci (44%). E. coli was detected in 12 samples (n = 30-food/food-handlers; phylogenetic groups A0/A1/B1) with 33% resistant to one or more antibiotics. Two multidrug resistant atypical E. coli pathotype strains (astA-ST165(CC165)/food-handler, eaeA-ST327/food) were detected. Three out of eight E. coli clonal lineages [ST409/ST976(CC10)/ST297] and the two L. monocytogenes clones were spread in different samples/trailers, suggesting cross-contamination or a common source of contamination. This exploratory study, in Porto region, showed ready-to-eat street foods from vending trailers as potential vehicles of clinically relevant L. monocytogenes serotypes and/or E. coli carrying clinically relevant virulence/antibiotic resistance features, and food-handlers as a critical risk factor in this expanding food sector.

Cuidados a los pacientes con ictus agudo: eficacia del ecógrafo vesical portátil en la unidad de ictus / Care for patients with acute stroke: effectiveness of portable vesical ultrasound imaging in the stroke unit

Introducción. Más de una tercera parte de los pacientes con ictus, en fase aguda, presenta trastornos urinarios que se deben evaluar y tratar. Objetivo. Valorar la eficacia de un ecógrafo portátil de vejiga en el cuidado de pacientes con ictus agudo. Pacientes y métodos. Ensayo clínico aleatorizado con pacientes con diagnóstico de ictus establecido y admitidos en la unidad de ictus entre julio de 2009 y febrero de 2010. Se monitorizó a los pacientes respecto a su función urinaria. En elgrupo control, entre otras medidas, se valoró la retención de orina con el método tradicional y en el grupo de intervención se valoró mediante un ecógrafo vesical portátil.Resultados. Se han estudiado 145 pacientes (78 del grupo de intervención y 67 del grupo control). Un 62,3% de los pacientesdel grupo de intervención presentó retención urinaria al ingreso con volúmenes superiores a 500 mL en el 14,3% de los casos. Se observaron más molestias suprapúbicas durante las primeras 24 horas en el grupo control (p < 0,05) y un porcentaje superior de retención urinaria en el grupo de intervención, durante las primeras 24 horas. Globalmente, observamos alguna disfunción urinaria en el 26,9% de los pacientes del grupo control y en el 23,1% del grupo de intervención (p > 0,05). Conclusiones. El ecógrafo vesical portátil se ha mostrado como un método eficaz que permitió un mayor control del paciente y detectó la retención de orina con precisión, de modo que evitó mayores molestias al paciente, por lo que recomendamos su incorporación en los cuidados de enfermería en fase aguda del ictus, sobre todo en los primeros días dehospitalización (AU)

Introduction. More than a third of the patients with acute stroke have urinary disorders that should be evaluated and treated.Aim. To evaluate the effectiveness of portable ultrasound scanner in patients with acute stroke.Patients and methods. Randomized clinical trial with stroke patients admitted consecutively to the stroke unit betweenJuly 2009 and February 2010. Patients were monitored for their urinary function. Specifically, the control group was assessed for retention of urine with the traditional method and the intervention group was assessed using a portable bladder scanner.Results. The study included 145 patients (78 in the intervention group and 67 in the control group). On admission, 62.3% of patients in the intervention group had urinary retention, with volumes above 500 mL in 14.3% of these patients. Wefound more difficult suprapubic discomfort during the first 24 hours in the control group (p < 0.05) and a higher frequency of urinary retention in intervention group during the first 24 hours. Urinary dysfunction was observed in 26.9% of the control group and in 23.1% of the intervention group (p < 0.05).Conclusions. The portable bladder ultrasound was an effective method that allowed greater control of the patient, it detected urine retention accurately, preventing further discomfort to the patient, and we recommend their incorporationin nursing care of acute stroke, especially in the first days of hospitalization (AU)

[Care for patients with acute stroke: effectiveness of portable vesical ultrasound imaging in the stroke unit]. / Cuidados a los pacientes con ictus agudo: eficacia del ecógrafo vesical portatil en la unidad de ictus.

INTRODUCTION: More than a third of the patients with acute stroke have urinary disorders that should be evaluated and treated. AIM: To evaluate the effectiveness of portable ultrasound scanner in patients with acute stroke. PATIENTS AND METHODS: Randomized clinical trial with stroke patients admitted consecutively to the stroke unit between July 2009 and February 2010. Patients were monitored for their urinary function. Specifically, the control group was assessed for retention of urine with the traditional method and the intervention group was assessed using a portable bladder scanner. RESULTS: The study included 145 patients (78 in the intervention group and 67 in the control group). On admission, 62.3% of patients in the intervention group had urinary retention, with volumes above 500 mL in 14.3% of these patients. We found more difficult suprapubic discomfort during the first 24 hours in the control group (p < 0.05) and a higher frequency of urinary retention in intervention group during the first 24 hours. Urinary dysfunction was observed in 26.9% of the control group and in 23.1% of the intervention group (p < 0.05). CONCLUSIONS: The portable bladder ultrasound was an effective method that allowed greater control of the patient, it detected urine retention accurately, preventing further discomfort to the patient, and we recommend their incorporation in nursing care of acute stroke, especially in the first days of hospitalization.

Detection of arc genes related with the ethyl carbamate precursors in wine lactic acid bacteria.

Trace amounts of the carcinogen ethyl carbamate can appear in wine by the reaction of ethanol with compounds such as citrulline and carbamyl phosphate, which are produced from arginine degradation by some wine lactic acid bacteria (LAB). In this work, the presence of arc genes for the arginine-deiminase pathway was studied in several strains of different species of LAB. Their ability to degrade arginine was also studied. To detect the presence of arc genes, degenerate primers were designed from the alignment of protein sequences in already sequenced LAB. The usefulness of these degenerate primers has been proven by sequencing some of the amplified PCR fragments and searching for homologies with published sequences of the same species and related ones. Correlation was found between the presence of genes and the ability to degrade arginine. Degrading strains included all heterofermentative lactobacilli, Oenococcus oeni , Pediococcus pentosaceus , and some strains of Leuconostoc mesenteroides and Lactobacillus plantarum .

The R6 lines of transgenic mice: a model for screening new therapies for Huntington's disease.

Huntington's disease (HD) is a hereditary neurodegenerative disorder caused by an expanded CAG repeat in the HD gene that results in cortical and striatal degeneration, and mutant huntingtin aggregation. Current treatments are unsatisfactory. R6 transgenic mice replicate many features of the human condition, show early onset of symptoms and fast disease progression, being one of the most used models for therapy screening. Here we review the therapies that have been tested in these mice: environmental enrichment, inhibition of histone deacetylation and methylation, inhibition of misfolding and oligomerization, transglutaminase inhibition, rescue of metabolic impairment, amelioration of the diabetic phenotype, use of antioxidants, inhibition of excitotoxicity, caspase inhibition, transplantation, genetic manipulations, and restoration of neurogenesis. Although many of these treatments were beneficial in R6 mice, they may not be as effective in HD patients, and thus the search for a combination of therapies that will rescue the human condition continues.

Mechanisms of neurodegeneration in Huntington's disease.

Huntington's disease (HD) is caused by an expansion of cytosine-adenine-guanine (CAG) repeats in the huntingtin gene, which leads to neuronal loss in the striatum and cortex and to the appearance of neuronal intranuclear inclusions of mutant huntingtin. Huntingtin plays a role in protein trafficking, vesicle transport, postsynaptic signaling, transcriptional regulation, and apoptosis. Thus, a loss of function of the normal protein and a toxic gain of function of the mutant huntingtin contribute to the disruption of multiple intracellular pathways. Furthermore, excitotoxicity, dopamine toxicity, metabolic impairment, mitochondrial dysfunction, oxidative stress, apoptosis, and autophagy have been implicated in the progressive degeneration observed in HD. Nevertheless, despite the efforts of a multidisciplinary scientific community, there is no cure for this devastating neurodegenerative disorder. This review presents an overview of the mechanisms that may contribute for HD pathogenesis. Ultimately, a better understanding of these mechanisms will lead to the development of more effective therapeutic targets.

Calpain activation is involved in early caspase-independent neurodegeneration in the hippocampus following status epilepticus.

Evidence for increased calpain activity has been described in the hippocampus of rodent models of temporal lobe epilepsy. However, it is not known whether calpains are involved in the cell death that accompanies seizures. In this work, we characterized calpain activation by examining the proteolysis of calpain substrates and in parallel we followed cell death in the hippocampus of epileptic rats. Male Wistar rats were injected with kainic acid (10 mg/kg) intraperitoneally and killed 24 h later, after development of grade 5 seizures. We observed a strong Fluoro-Jade labeling in the CA1 and CA3 areas of the hippocampus in the rats that received kainic acid, when compared with saline-treated rats. Immunohistochemistry and western blot analysis for the calpain-derived breakdown products of spectrin showed evidence of increased calpain activity in the same regions of the hippocampus where cell death is observed. No evidence was found for caspase activation, in the same conditions. Treatment with the calpain inhibitor MDL 28170 significantly prevented the neurodegeneration observed in CA1. Taken together, our data suggest that early calpain activation, but not caspase activation, is involved in neurotoxicity in the hippocampus after status epilepticus.

Progressive alterations in the hypothalamic-pituitary-adrenal axis in the R6/2 transgenic mouse model of Huntington's disease.

Huntington's disease (HD) is characterized by a triad of motor, psychiatric and cognitive symptoms. Although many of these symptoms are likely to be related to central nervous system pathology, others may be due to changes in peripheral tissues. The R6/2 mouse, a transgenic model of HD expressing exon 1 of the human HD gene, develops progressive alterations in the hypothalamic-pituitary-adrenal axis, reminiscent of a Cushing-like syndrome. We observed muscular atrophy, reduced bone mineral density, abdominal fat accumulation and insulin resistance in the mice. All these changes could be consequences of increased glucocorticoid levels. Indeed, hypertrophy of the adrenal cortex and a progressive increase in serum and urine corticosterone levels were found in R6/2 mice. In addition, the intermediate pituitary lobe was markedly enlarged and circulating adreno-corticotrophic hormone (ACTH) increased. Under normal conditions dopamine represses the ACTH expression. In the R6/2 mice, however, the expression of pituitary dopamine D2 receptors was reduced by half, possibly explaining the increase in ACTH. Urinary samples from 82 HD patients and 68 control subjects were analysed for cortisol: in accord with the observations in the R6/2 mice, urinary cortisol increased in parallel with disease progression. This progressive increase in cortisol may contribute to the clinical symptoms, such as muscular wasting, mood changes and some of the cognitive deficits that occur in HD.

Reduced hippocampal neurogenesis in R6/2 transgenic Huntington's disease mice.

We investigated whether cell proliferation and neurogenesis are altered in R6/2 transgenic Huntington's disease mice. Using bromodeoxyuridine (BrdU), we found a progressive decrease in the number of proliferating cells in the dentate gyrus of R6/2 mice. This reduction was detected in pre-symptomatic mice, and by 11.5 weeks, R6/2 mice had 66% fewer newly born cells in the hippocampus. The results were confirmed by immunohistochemistry for the cell cycle markers Ki-67 and proliferating cell nuclear antigen (PCNA). We did not observe changes in cell proliferation in the R6/2 subventricular zone, indicating that the decrease in cell proliferation is specific for the hippocampus. This decrease corresponded to a reduction in actual hippocampal neurogenesis as assessed by double immunostaining for BrdU and the neuronal marker neuronal nuclei (NeuN) and by immunohistochemistry for the neuroblast marker doublecortin. Reduced hippocampal neurogenesis may be a novel neuropathological feature in R6/2 mice that could be assessed when evaluating potential therapies.

Proteolysis of NR2B by calpain in the hippocampus of epileptic rats.

Overactivation of N-methyl-D-aspartate receptors is known to mediate excitotoxicity due to excessive entry of calcium, leading to the activation of several calcium-dependent enzymes. Calpains are calcium-activated proteases that appear to play a role in excitotoxic neuronal death. Several cellular proteins are substrates for these proteases, particularly the N-methyl-D-aspartate receptor. Recently, cleavage of NR2B subunits has been implicated in excitotoxic neurodegeneration in ischemia. In this work, we investigated the proteolysis by calpains of NR2B subunits of the N-methyl-D-aspartate receptor in the hippocampus of epileptic rats. Our results show that cleaved forms of NR2B subunits are formed after status epilepticus, in the same areas of the hippocampus where calpain activation was detected by immunohistochemical staining of calpain-specific spectrin breakdown products.

The R6/2 transgenic mouse model of Huntington's disease develops diabetes due to deficient beta-cell mass and exocytosis.

Diabetes frequently develops in Huntington's disease (HD) patients and in transgenic mouse models of HD such as the R6/2 mouse. The underlying mechanisms have not been clarified. Elucidating the pathogenesis of diabetes in HD would improve our understanding of the molecular mechanisms involved in HD neuropathology. With this aim, we examined our colony of R6/2 mice with respect to glucose homeostasis and islet function. At week 12, corresponding to end-stage HD, R6/2 mice were hyperglycemic and hypoinsulinemic and failed to release insulin in an intravenous glucose tolerance test. In vitro, basal and glucose-stimulated insulin secretion was markedly reduced. Islet nuclear huntingtin inclusions increased dramatically over time, predominantly in beta-cells. beta-cell mass failed to increase normally with age in R6/2 mice. Hence, at week 12, beta-cell mass and pancreatic insulin content in R6/2 mice were 35+/-5 and 16+/-3% of that in wild-type mice, respectively. The normally occurring replicating cells were largely absent in R6/2 islets, while no abnormal cell death could be detected. Single cell patch-clamp experiments revealed unaltered electrical activity in R6/2 beta-cells. However, exocytosis was virtually abolished in beta- but not in alpha-cells. The blunting of exocytosis could be attributed to a 96% reduction in the number of insulin-containing secretory vesicles. Thus, diabetes in R6/2 mice is caused by a combination of deficient beta-cell mass and disrupted exocytosis.

Orexin loss in Huntington's disease.

Huntington's disease (HD) is a devastating neurodegenerative disorder caused by an expanded CAG repeat in the gene encoding huntingtin, a protein of unknown function. Mutant huntingtin forms intracellular aggregates and is associated with neuronal death in select brain regions. The most studied mouse model (R6/2) of HD replicates many features of the disease, but has been reported to exhibit only very little neuronal death. We describe for the first time a dramatic atrophy and loss of orexin neurons in the lateral hypothalamus of R6/2 mice. Importantly, we also found a significant atrophy and loss of orexin neurons in Huntington patients. Like animal models and patients with impaired orexin function, the R6/2 mice were narcoleptic. Both the number of orexin neurons in the lateral hypothalamus and the levels of orexin in the cerebrospinal fluid were reduced by 72% in end-stage R6/2 mice compared with wild-type littermates, suggesting that orexin could be used as a biomarker reflecting neurodegeneration. Our results show that the loss of orexin is a novel and potentially very important pathology in HD.