Blade life span, structural investment, and nutrient allocation in giant kelp.

The turnover of plant biomass largely determines the amount of energy flowing through an ecosystem and understanding the processes that regulate turnover has been of interest to ecologists for decades. Leaf life span theory has proven useful in explaining patterns of leaf turnover in relation to resource availability, but the predictions of this theory have not been tested for macroalgae. We measured blade life span, size, thickness, nitrogen content, pigment content, and maximum photosynthetic rate (P max) in the giant kelp (Macrocystis pyrifera) along a strong resource (light) gradient to test whether the predictions of leaf life span theory applied to this alga. We found that shorter blade life spans and larger blade areas were associated with increased light availability. In addition, nitrogen and P max decreased with blade age, and their decrease was greater in shorter lived blades. These observations are generally consistent with patterns observed for higher plants and the prevailing theory of leaf life span. By contrast, variation observed in pigments of giant kelp was inconsistent with that predicted by leaf life span theory, as blades growing in the most heavily shaded portion of the forest had the lowest chlorophyll content. This result may reflect the dual role of macroalgal blades in carbon fixation and nutrient absorption and the ability of giant kelp to modify blade physiology to optimize the acquisition of light and nutrients. Thus, the marine environment may place demands on resource acquisition and allocation that have not been previously considered with respect to leaf life span optimization.

The importance of progressive senescence in the biomass dynam of giant kelp (Macrocystis pyrifera).

Temporal variation in primary producer biomass has profound effects on the structure and function of the surrounding ecological community. The giant kelp (Macrocystis pyrifera) exhibits strong intra-annual variation in biomass density, which is better explained by the demographic rates of fronds than by those of whole plants. To better understand the processes controlling the dynamics of giant kelp fronds we collected monthly time-series data of frond initiation and survival. These data were used to determine how frond loss and frond initiation rates were predicted by factors thought to affect the growth and survival of Macrocystis, including external environmental factors (i.e., wave height, day length, temperature, nutrient concentration, and neighborhood density) and intrinsic biological characteristics (i.e., frond age, plant size, and nutritional status). Our results revealed that frond dynamics were better explained by intrinsic biological processes rather than external environmental factors. A metric of frond age structure that incorporated progressive senescence was the best predictor of frond loss rate, accounting for 58% of the explained variation in frond loss. A similar analysis revealed that frond age structure was also the single best predictor of frond initiation rate, accounting for 46% of the explained variation. To further examine the importance of senescence in biomass dynamics, we used frond age-dependent mortality and frond initiation rates to predict biomass in subsequent months and found that the model explained 73% of the observed variation in biomass at our sites. Vegetation dynamics of many species including giant kelp are often considered largely in the context of external controls on resource availability and physical disturbance. Our results indicate that investigations of the processes controlling vegetation dynamics may benefit greatly from the inclusion of intrinsic biological factors such as age-dependent mortality and growth, which can outweigh the effects of external forcing in accounting for fluctuations in vegetation biomass.

Masitinib as an add-on therapy to riluzole in patients with amyotrophic lateral sclerosis: a randomized clinical trial.

Objective: To assess masitinib in the treatment of ALS. Methods: Double-blind study, randomly assigning 394 patients (1:1:1) to receive riluzole (100 mg/d) plus placebo or masitinib at 4.5 or 3.0 mg/kg/d. Following a blinded transition from phase 2 to phase 2/3, a prospectively defined two-tiered design was implemented based on ALSFRS-R progression rate from disease-onset to baseline (ΔFS). This approach selects a more homogeneous primary efficacy population ("Normal Progressors", ΔFS < 1.1 points/month) while concurrently permitting secondary assessment of the broader population. Primary endpoint was decline in ALSFRS-R at week-48 (ΔALSFRS-R), with the high-dose "Normal Progressor" cohort being the prospectively declared primary efficacy population. Missing data were imputed via last observation carried forward (LOCF) methodology with sensitivity analyses performed to test robustness. Results: For the primary efficacy population, masitinib (n = 99) showed significant benefit over placebo (n = 102) with a ΔALSFRS-R between-group difference (ΔLSM) of 3.4 (95% CI 0.65-6.13; p = 0.016), corresponding to a 27% slowing in rate of functional decline (LOCF methodology). Sensitivity analyses were all convergent, including the conservative multiple imputation technique of FCS-REGPMM with a ΔLSM of 3.4 (95% CI 0.53-6.33; p = 0.020). Secondary endpoints (ALSAQ-40, FVC, and time-to-event analysis) were also significant. Conversely, no significant treatment-effect according to ΔALSFRS-R was seen for the broader "Normal and Fast Progressor" masitinib 4.5 mg/kg/d cohort, or either of the low-dose (masitinib 3.0 mg/kg/d) cohorts. Rates of treatment-emergent adverse events (AEs) (regardless of causality or post-onset ΔFS) were 88% with masitinib 4.5 mg/kg/d, 85% with 3.0 mg/kg/d, and 79% with placebo. Likewise, rates of serious AE were 31, 23, and 18%, respectively. No distinct event contributed to the higher rate observed for masitinib and no deaths were related to masitinib. Conclusions: Results show that masitinib at 4.5 mg/kg/d can benefit patients with ALS. A confirmatory phase 3 study will be initiated to substantiate these data.

Predictors of amyotrophic lateral sclerosis mimic syndrome.

The term amyotrophic lateral sclerosis mimic syndrome (ALSms) includes pathologies that present signs or symptoms similar to those caused by amyotrophic lateral sclerosis (ALS), which can lead to misdiagnosis. In general, any kind of misdiagnosis can result in negative clinical, psychological and economic consequences as well diagnostic and treatment delay. The objectives were to determine the frequency and to compare the demographic and clinical characteristics of patients with ALS and ALSms in our ALS clinic. We retrospectively studied all patients evaluated from 2007 to 2017 including only patients with a definite final diagnosis. Out of 368 patients with motor neuron disease symptomatology, 43 (11.7%) had an ALSms. The most frequent etiology was compressive myelopathy (32.6%). Multivariate analysis considering positive associations was statistically significant for patients having only upper or lower motor neuron signs in the physical examination, a non-compatible electromyogram (EMG), as well as atypical first symptoms. ALS misdiagnosis is an ongoing and not infrequent problem. From our series of patients, atypical symptoms, absence of EMG pathological findings or isolated upper or lower motor neuron disease should prompt suspicion of a differential diagnosis.

Everything you always wanted to know about sex and Neurology: neurological disability and sexuality.

OBJECTIVE: Chronic neurological disorders generate disabilities affecting multiple aspects of life, including sexuality. OBJECTIVE: To describe the presence of sexual dysfunction and comorbidities in a population with chronic neurological disorders. To analyze the relationship between disability and sexual dysfunction. METHODS: A cross-sectional case-control study was carried out. Patients with amyotrophic lateral sclerosis (ALS), multiple sclerosis (MS), Parkinson's disease (PD), and stroke of at least one year since the onset of symptoms were included, and compared with controls with no neurological disease, matched by age and sex. RESULTS: We included 71 participants: 29 controls, with a mean age of 49.4 years, and 42 patients with a mean age of 53.8 years. Sexual dysfunction was present in 22.5% of the controls and 77.5% of the patients. A statistically significant relationship between sexual dysfunction and disability was found in the logistic regression analysis (OR = 20.38, 95%CI: 2.5 -165.86). CONCLUSIONS: Disability proved to be the main variable related to the presence of sexual dysfunction. Patients with ALS had the worst rates of sexual dysfunction. Patients with MS were similar to the control group. As for the PD group, no patient had normal sexuality. Finally, in stroke patients, the presence of comorbidities and their treatment may have negatively influenced sexuality. These findings showed that patients with chronic neurological diseases have sexual dysfunction and underscore the need for neurologists to know and address this problem.

Outcome of sporadic amyotrophic lateral sclerosis treated with non-invasive ventilation and riluzole.

Sporadic amyotrophic lateral sclerosis (sALS) is a progressive degenerative motor neuron disorder lacking specific treatment. Riluzole is the only drug able to modestly slow down the course of the disease. Respiratory insufficiency is the main cause of death; non invasive ventilation (NIV) has shown to improve survival. Our aim was to evaluate the effect of NIV and riluzole on survival. Ninety seven patients with a diagnosis of sALS were assessed and followed up for 60 months. Twenty nine patients received NIV and 68 did not (nNIV). Overall median survival In the NIV group was 15.41 +/- 7.78 months vs. 10.88 +/- 7.78 months in the nNIV group (p= 0.028). Median survival time was not different in patients receiving riluzole (n=44), as compared with those who did not (n=53), although at month 4th and 5th riluzole treated patients showed a modest benefit. In those who only received NIV (n=11) or only riluzole (n=26), survival time was 13.45 +/- 13.44 months and 11.19 +/- 7.79 months, respectively. Patients who received both NIV and riluzole (n=18) had a median survival time of 16.61 +/- 10.97 months vs. 10.69 +/- 7.86 months for those who received only supportive treatment (n=42) (p= 0.021). NIV improved survival in our series of patients. Riluzole did not show any significant impact on survival when employed as the only therapy. Patients receiving both treatments simultaneously had a significant longer survival.

Everything you always wanted to know about sex and Neurology: neurological disability and sexuality / Todo lo que siempre quiso saber sobre sexo y Neurologia pero nunca se atrevió a preguntar: estudio sobre discapacidad neurologica y sexualidad

ABSTRACT Chronic neurological disorders generate disabilities affecting multiple aspects of life, including sexuality. Objective To describe the presence of sexual dysfunction and comorbidities in a population with chronic neurological disorders. To analyze the relationship between disability and sexual dysfunction. Methods A cross-sectional case-control study was carried out. Patients with amyotrophic lateral sclerosis (ALS), multiple sclerosis (MS), Parkinson's disease (PD), and stroke of at least one year since the onset of symptoms were included, and compared with controls with no neurological disease, matched by age and sex. Results We included 71 participants: 29 controls, with a mean age of 49.4 years, and 42 patients with a mean age of 53.8 years. Sexual dysfunction was present in 22.5% of the controls and 77.5% of the patients. A statistically significant relationship between sexual dysfunction and disability was found in the logistic regression analysis (OR = 20.38, 95%CI: 2.5 -165.86). Conclusions Disability proved to be the main variable related to the presence of sexual dysfunction. Patients with ALS had the worst rates of sexual dysfunction. Patients with MS were similar to the control group. As for the PD group, no patient had normal sexuality. Finally, in stroke patients, the presence of comorbidities and their treatment may have negatively influenced sexuality. These findings showed that patients with chronic neurological diseases have sexual dysfunction and underscore the need for neurologists to know and address this problem.

RESUMO Las enfermedades neurológicas crónicas generan discapacidad afectando múltiples aspectos de la vida, incluida la sexual. Objetivo Describir en una población con enfermedades neurológicas crónicas la presencia de disfunción sexual y posibles comorbilidades acompañantes. Analizar la relación entre discapacidad y disfunción sexual. Métodos Se realizó un estudio transversal de tipo casos y controles. Se incluyeron pacientes con Esclerosis Lateral Amiotrófica (ELA), Esclerosis Múltiple (EM), enfermedad de Parkinson (EP) y secuelados por enfermedad cerebrovascular (sACV) de al menos un año de evolución, controlando con sujetos sin enfermedad neurológica pareados por edad y sexo. Resultados Se incluyeron 71 sujetos: 29 controles, con una edad media 49,4 años y 42 casos con una edad media de 53,8 años. Presentaron disfunción sexual el 22,5% de los controles y el 77,5% de los casos. En el análisis por regresión logística se encontró una relación estadísticamente significativamente entre disfunción sexual y discapacidad. (OR = 20.38, IC95%: 2.5-165.86). Conclusiones La discapacidad demostró ser la principal variable relacionada con la presencia de disfunción sexual. Los enfermos con ELA fueron los que peores índices de disfunción sexual presentaron. Los pacientes con EM se comportaron de forma similar al grupo control. En cuanto al grupo de EP todos los pacientes tuvieron algún trastorno en su sexualidad. Por último, en sACV la presencia de comorbilidades y su tratamiento podrían influir negativamente en la sexualidad. Estos hallazgos evidencian que la disfunción sexual está presente en los pacientes con enfermedades neurológicas crónicas y confirma la necesidad de conocer este problema por parte de los neurólogos.

Morphological abnormalities in mitochondria of the skin of patients with sporadic amyotrophic lateral sclerosis.

OBJECTIVES: Mitochondrial dysfunction has been reported in the central nervous system, hepatocytes and peripheral blood lymphocytes from patients with sporadic amyotrophic lateral sclerosis (SALS). However, the status of skin mitochondria has not been reported, in spite of the fact that SALS patients present skin abnormalities. The objective of the present study was to compare mitochondrial ultrastructural parameters in keratinocytes from patients with SALS and healthy controls. METHODS: Our study was based on the analysis of 112 skin mitochondria from 5 SALS patients and 99 organelles from 4 control subjects by electron microscopy. RESULTS: Computerized image analysis showed that mitochondrial major axis length, area and perimeter of the organelle were significantly smaller in SALS respect of healthy control subjects. Morphologically, SALS mitochondria presented cristolysis and breakage of the outer membrane. CONCLUSIONS: Mitochondrial dysfunction in the skin may possibly reflect changes occurring in mitochondria of the central nervous system. The analysis of mitochondrial morphology in this tissue may be of value to follow disease progression and, eventually, the effectiveness of current therapies for SALS.

Morphological abnormalities in mitochondria of the skin of patients with sporadic amyotrophic lateral sclerosis / Alteraciones morfológicas en las mitocondrias en la piel de enfermos con esclerosis lateral amiotrófica esporádica

OBJECTIVES: Mitochondrial dysfunction has been reported in the central nervous system, hepatocytes and peripheral blood lymphocytes from patients with sporadic amyotrophic lateral sclerosis (SALS). However, the status of skin mitochondria has not been reported, in spite of the fact that SALS patients present skin abnormalities. The objective of the present study was to compare mitochondrial ultrastructural parameters in keratinocytes from patients with SALS and healthy controls. METHODS: Our study was based on the analysis of 112 skin mitochondria from 5 SALS patients and 99 organelles from 4 control subjects by electron microscopy. RESULTS: Computerized image analysis showed that mitochondrial major axis length, area and perimeter of the organelle were significantly smaller in SALS respect of healthy control subjects. Morphologically, SALS mitochondria presented cristolysis and breakage of the outer membrane. CONCLUSIONS: Mitochondrial dysfunction in the skin may possibly reflect changes occurring in mitochondria of the central nervous system. The analysis of mitochondrial morphology in this tissue may be of value to follow disease progression and, eventually, the effectiveness of current therapies for SALS.

OBJETIVOS: Existen alteraciones en la función mitocondrial en el sistema nervioso central, en hepatocitos y en linfocitos de sangre periférica en SALS. Aunque, no se ha estudiado si existen cambios estructurales en las mitocondrias de la piel. Nuestro objetivo fue comparar la ultraestructura de mitocondrias en queratinocitos de enfermos con SALS con la de controles sanos. MÉTODO: Fueron analizadas en el microscopio electrónico 112 mitocondrias dérmicas de 5 pacientes y 99 provenientes de 4 controles. RESULTADOS: EL análisis computarizado mostró que el eje mayor mitocondrial, el área y el perímetro de las organelas fueran significativamente menor que en controles. Morfológicamente, las mitocondrias de SALS presentaron cristólisis y ruptura de la membrana externa. CONCLUSIÓN: La alteración mitocondrial en la piel posiblemente refleje cambios que también ocurran en las mitocondrias neuronales. Este análisis morfológico de las mitocondrias podría tener valor en el seguimiento de la enfermedad y eventualmente en la evaluación de la efectividad de futuras terapias.

Outcome of sporadic amyotrophic lateral sclerosis treated with non-invasive ventilation and riluzole / Sobrevida en pacientes con esclerosis lateral amiotrófica esporádica tratados con ventilación no invasiva y riluzole

Sporadic amyotrophic lateral sclerosis (sALS) is a progressive degenerative motor neuron disorder lacking specific treatment. Riluzole is the only drug able to modestly slow down the course of the disease. Respiratory insufficiency is the main cause of death; non invasive ventilation (NIV) has shown to improve survival. Our aim was to evaluate the effect of NIV and riluzole on survival. Ninety seven patients with a diagnosis of sALS were assessed and followed up for 60 months. Twenty nine patients received NIV and 68 did not (nNIV). Overall median survival In the NIV group was 15.41 ± 7.78 months vs. 10.88 ± 7.78 months in the nNIV group (p= 0.028). Median survival time was not different in patients receiving riluzole (n=44), as compared with those who did not (n=53), although at month 4th and 5th riluzole treated patients showed a modest benefit. In those who only received NIV (n=11) or only riluzole (n=26), survival time was 13.45 ± 13.44 months and 11.19 ± 7.79 months, respectively. Patients who received both NIV and riluzole (n=18) had a median survival time of 16.61 ± 10.97 months vs. 10.69 ± 7.86 months for those who received only supportive treatment (n=42) (p= 0.021). NIV improved survival in our series of patients. Riluzole did not show any significant impact on survival when employed as the only therapy. Patients receiving both treatments simultaneously had a significant longer survival.

La esclerosis lateral amiotrófica esporádica (sALS) es una enfermedad degenerativa para la que no existe tratamiento etiológico eficaz. El riluzole prolonga poco la sobrevida. La principal causa de muerte es la insuficiencia respiratoria. Uno de los tratamientos para esta última es la ventilación asistida no invasiva (NIV) con equipos de doble nivel de presión. El objetivo de este trabajo fue determinar el impacto en la sobrevida de estos enfermos combinando ventilación no invasiva y riluzole. Se evaluaron y siguieron durante 60 meses 97 pacientes con diagnóstico de sALS, según criterios definidos en El Escorial modificados, y fueron seguidos por 60 meses. Veintinueve pacientes recibieron NIV y 68 no (nNIV). En el grupo NIV la sobrevida media fue de 15.41 ± 7.78 meses vs. 10.88 ± 7.78 meses en nNIV (p= 0.028). La sobrevida media de los pacientes que recibieron riluzole (n=44) no fue diferente de la que no lo recibieron (n=53), aunque en el 4° y 5° mes los pacientes tratados con riluzole mostraron un escaso beneficio. Los pacientes que recibieron NIV y riluzole (n=18) tuvieron una sobrevida media de 16.61 ± 10.97 meses vs. 10.69 ± 7.86 meses para los que sólo recibieron tratamiento sintomático (n=42) (p= 0.021). La NIV prolongó significativamente la sobrevida en este grupo de pacientes. El riluzole, empleado como única terapéutica, no lo hizo. Los pacientes que combinaron los dos tratamientos tuvieron la mayor sobrevida.

Evaluación del estado nutricional en pacientes con Esclerosis Lateral Amiotrófica. Comparación del valor de diferentes parámetros antropométricos / Evaluation of the nutritional condition in patients with amyotrophic lateral sclerosis. Comparison amongst different anthropometric measurements

En los pacientes con Esclerosis Lateral Amikotrófica (ELA) el déficit nutriciional es un factor predictivo negativo indpendiente de sobrevida. Por este motivo, la intervención nutricional es parte del tratamiento paliativo. Nuestro objetivo fue evaluar el estado nutricional en pacientes con ELA

Evaluación fonodeglutoria en pacients con esclerosis lateral amiotrófica / Evaluation of speech and seallowing disorders in patients with amyotrophic lateral sclerosis

En la Esclerosis lateral Amiotrófica (ELA) el treinta por ciento de los pacientes comienza con síntomas bulbares que incluyen disfagia, disartria y alteraciones fonatorias. No es claro si el comporomiso bulbar implica el deterioro simultáneo de las tres funciones o si ellas pueden tener una evolución independiente. Existen escalas para evaluar individualmente esas funciones que son de dificil cuantificación clínica. La detección y la mensura adecuada de sus alteraciones permiten apreciar adecuadamente la discapacidad existente