Reduction of alpha-synuclein oligomers in preclinical models of Parkinson's disease by electrical stimulation in vitro and deep brain stimulation in vivo.

BACKGROUND: Deep brain stimulation (DBS) has been widely used to manage debilitating neurological symptoms in movement disorders such as Parkinson's disease (PD). Despite its well-established symptomatic benefits, our understanding of the mechanisms underlying DBS and its possible effect on the accumulation of pathological proteins in neurodegeneration remains limited. Accumulation and oligomerization of the protein alpha-synuclein (α-Syn) are implicated in the loss of dopaminergic neurons in the substantia nigra in PD, making α-Syn a potential therapeutic target for disease modification. OBJECTIVE: We examined the effects of high frequency electrical stimulation on α-Syn levels and oligomerization in cell and rodent models. METHODS: High frequency stimulation, mimicking DBS parameters used for PD, was combined with viral-mediated overexpression of α-Syn in cultured rat primary cortical neurons or in substantia nigra of rats. Bimolecular protein complementation with split fluorescent protein reporters was used to detect and quantify α-Syn oligomers. RESULTS: High frequency electrical stimulation reduced the expression of PD-associated mutant α-Syn and mitigated α-Syn oligomerization in cultured neurons. Furthermore, DBS in the substantia nigra, but not the subthalamic nucleus, decreased overall levels of α-Syn, including oligomer levels, in the substantia nigra. CONCLUSIONS: Taken together, our results demonstrate that direct high frequency stimulation can reduce accumulation and pathological forms of α-Syn in cultured neurons in vitro and in substantia nigra in vivo. Thus, DBS therapy could have a role beyond symptomatic treatment, with potential disease-modifying properties that can be exploited to target pathological proteins in neurodegenerative diseases.

The effect of limited healthcare access on poor outcomes among hospitalized COVID-19 patients in Honduras: A single center cohort study.

Background: The COVID-19 pandemic has had a severe impact on the Latin American subcontinent, particularly in areas with limited hospital resources and a restricted Intensive Care Unit (ICU) capacity. This study aimed to provide a comprehensive description of the clinical characteristics, outcomes, and factors associated with survival of COVID-19 hospitalized patients in Honduras. Research question: What were the characteristics and outcomes of COVID-19 patients in a large referral center in Honduras? Study design and methods: This study employed a retrospective cohort design conducted in a single center in San Pedro Sula, Honduras, between October 2020 to March 2021. All hospitalized cases of confirmed COVID-19 during this timeframe were included in the analysis. Univariable and multivariable survival analysis were performed using Kaplan-Meier curves and Cox proportional hazards model aiming to identify factors associated with decreased 30 day in-hospital survival, using a priori-selected factors. Results: A total of 929 confirmed cases were identified in this cohort, with males accounting for 55.4 % of cases. The case fatality rate among the hospitalized patients was found to be 50.1 % corresponding to 466 deaths. Patients with comorbidities such as hypertension, diabetes, obesity, chronic kidney disease, chronic obstructive pulmonary disease and cardiovascular disease had a higher likelihood of mortality. Additionally, non-survivors had a significantly longer time from illness onset to hospital admission compared to survivors (8.2 days vs 4.7 days). Among the cohort, 306 patients (32.9 %) met criteria for ICU admission. However, due to limited capacity, only 60 patients (19·6 %) were admitted to the ICU. Importantly, patients that were unable to receive level-appropriate care had lower likelihood of survival compared to those who received level-appropriate care (hazard ratio: 1.84). Interpretation: This study represents, the largest investigation of in-hospital COVID-19 cases in Honduras and Central America. The findings highlight a substantial case fatality rate among hospitalized patients. In this study, patients who couldn't receive level-appropriate care (ICU admission) had a significantly lower likelihood of survival when compared to those who did. These results underscore the significant impact of healthcare access during the pandemic, particularly in low- and middle-income countries.

Spatial analysis and risk mapping of Fasciola hepatica infection in dairy cattle at the Peruvian central highlands.

This study aimed to develop maps for Fasciola hepatica infection occurrence in dairy cattle in the districts of Matahuasi and Baños in the Peruvian central highlands. For this, a model based on the correlation between environmental variables and the prevalence of infection was constructed. Flukefinder® coprological test were performed in samples from dairy cattle from 8 herds, during both the rainy and wet season. Grazing plots were geo-referenced to obtain information on environmental variables. Monthly temperature, monthly rainfall, elevation, slope, normalized difference vegetation index (NDVI), enhanced vegetation index (EVI), normalized difference water index (NDWI), distance to rivers, urban areas and roads were obtained by using remote sensor images and ArcGIS®. Multilayer perceptron Artificial Neural Networks modeling were applied to construct a predictive model for the occurrence of fasciolosis, based on the relationship between environmental variables and level of infection. Kappa coefficient (k > 0.6) was used to evaluate concordance between observed and forecasted risk by the model. Coprological results demonstrated an average prevalence from 20% to 100%, in Matahuasi, and between 0 and 87.5%, in Baños. A model with a high level of concordance between predicted and observed infection risk (k = 0.77) was obtained, having as major predicting variables: slope, NDWI, NDVI and EVI. Fasciolosis risk was categorized as low (p < 20%), medium (20% < p < 50%) and high (p ≥ 50%) level. Using ArcGIS 10.4.1, risk maps were developed for each risk level of fasciolosis. Maps of fasciolosis occurrence showed that 87.2% of Matahuasi area presented a high risk for bovine fasciolosis during the dry season, and 76.6% in the wet season. In contrast, 21.9% of Baños area had a high risk of infection during the dry season and 12.1% during the wet season. In conclusion, our model showed areas with high risk for fasciolosis occurrence in both districts during both dry and rainy periods. Slope, NDWI, NDVI and EVI were the major predictors for fasciolosis occurrence.

Trends and disparities in deep brain stimulation utilization in the United States: a Nationwide Inpatient Sample analysis from 1993 to 2017.

Background: Deep brain stimulation (DBS) is an approved treatment option for Parkinson's Disease (PD), essential tremor (ET), dystonia, obsessive-compulsive disorder and epilepsy in the United States. There are disparities in access to DBS, and clear understanding of the contextual factors driving them is important. Previous studies aimed at understanding these factors have been limited by single indications or small cohort sizes. The aim of this study is to provide an updated and comprehensive analysis of DBS utilization for multiple indications to better understand the factors driving disparities in access. Methods: The United States based National Inpatient Sample (NIS) database was utilized to analyze the surgical volume and trends of procedures based on indication, using relevant ICD codes. Predictors of DBS use were analyzed using a logistic regression model. DBS-implanted patients in each indication were compared based on the patient-, hospital-, and outcome-related variables. Findings: Our analysis of 104,356 DBS discharges from 1993 to 2017 revealed that the most frequent indications for DBS were PD (67%), ET (24%), and dystonia (4%). Although the number of DBS procedures has consistently increased over the years, radiofrequency ablation utilization has significantly decreased to only a few patients per year since 2003. Negative predictors for DBS utilization in PD and ET cohorts included age increase and female sex, while African American status was a negative predictor across all cohorts. Significant differences in patient-, hospital-, and outcome-related variables between DBS indications were also determined. Interpretation: Demographic and socioeconomic-based disparities in DBS use are evident. Although racial disparities are present across all indications, other disparities such as age, sex, wealth, and insurance status are only relevant in certain indications. Funding: This work was supported by Alan & Susan Hudson Cornerstone Chair in Neurosurgery at University Health Network.

Spinal Cord Stimulation for Parkinson's Disease: A Systematic Review and Meta-Analysis of Pain and Motor Outcomes.

BACKGROUND: Spinal cord stimulation (SCS) has been investigated as a potential therapeutic option for managing refractory symptoms in patients with Parkinson's disease (PD). OBJECTIVE: This systematic review and meta-analysis aimed to evaluate the safety and efficacy of SCS in PD. METHOD: A comprehensive literature search was conducted on PubMed and Web of Science to identify SCS studies reporting Unified Parkinson Disease Rating Scale-III (UPDRS-III) or Visual Analogue Scale (VAS) score changes in PD cohorts with at least 3 patients and a follow-up period of at least 1 month. Treatment effect was measured as the mean change in outcome scores and analyzed using an inverse variance random-effects model. The risk of bias was assessed using the Newcastle-Ottawa Scale and funnel plots. RESULTS: A total of 11 studies comprising 76 patients were included. Nine studies involving 72 patients reported an estimated decrease of 4.43 points (95% confidence interval [CI]: 2.11; 6.75, p < 0.01) in UPDRS-III score, equivalent to a 14% reduction. The axial subscores in 48 patients decreased by 2.35 points (95% CI: 1.26; 3.45, p < 0.01, 20% reduction). The pooled effect size of five studies on back and leg pain VAS scores was calculated as 4.38 (95% CI: 2.67; 6.09, p < 0.001), equivalent to a 59% reduction. CONCLUSIONS: Our analysis suggests that SCS may provide significant motor and pain benefits for patients with PD, although the results should be interpreted with caution due to several potential limitations including study heterogeneity, open-label designs, small sample sizes, and the possibility of publication bias. Further research using larger sample sizes and placebo-/sham-controlled designs is needed to confirm effectiveness.

Recharge PSYCH: A Study on Rechargeable Implantable Pulse Generators in Deep Brain Stimulation for Psychiatric Disorders.

BACKGROUND: Rechargeable implantable pulse generators (r-IPGs) for deep brain stimulation (DBS) promise longer battery life and fewer replacement surgeries versus non-rechargeable systems. Long-term data on the effects of recharging in patients who received DBS for psychiatric indications is limited. The Recharge PSYCH trial is the first study that included DBS patients with psychiatric disorders treated with different r-IPG models. METHODS: Standardized questionnaires were sent to all psychiatric DBS patients with an r-IPG implanted at the time of the study. The primary endpoint was convenience of recharging. Secondary endpoints were rate of user confidence and rate of usage-related complications, as well as charge burden (defined as minutes per week needed to recharge). RESULTS: Data sets of n = 21 patients were eligible for data analysis. At the time of the survey patients were implanted with the r-IPG for a mean 31.8 ± 22.4 months. Prior to being implanted with an r-IPG, patients had undergone a median of 3 IPG replacements. The overall convenience of the charging process was rated as "easy" with a median of 8.0 out of 10.0 points. 33.3% of patients experienced situations in which the device could not be successfully recharged. In 38.1% of patients, therapy with the r-IPG was interrupted unintentionally. The average charge burden was 286 ± 22.4 minutes per week. CONCLUSIONS: Patients with psychiatric disorders rated the recharging process as "easy", but with a significantly higher charge burden and usage-related complication rates compared to published data on movement disorder DBS patients.

Functionalization of Poly(styrene-co-methyl methacrylate) Particles for Selective Removal of Bilirubin.

Hyperbilirubinemia is one of the main causes of death in patients with severe hepatic problems, which justifies the research for bilirubin removal solutions. In this study, St-MMA particles with PEGMA and/or GMA brushes were synthesized. First, the recipe for St-MMA was optimized and then adapted for PEGMA and GMA incorporation. Different solvents were then assayed to improve the BSA immobilization capacity of the particles. Ethyl lactate proved to be the best solvent, reaching a BSA immobilization capacity improvement of up to 60% for St-MMA-GMA-PEGMA particles. These particles also presented the best results for BR removal from PBS. No significant differences in the final capacity for BR removal from PBS media were observed when BSA was attached to the particles; however, the kinetics were greatly improved, requiring half the time. Finally, St-MMA-GMA-PEGMA particles that were wetted in EL with BSA reduced the bilirubin concentration in plasma from levels that threaten the survival of critical patients to levels close to those of healthy individuals in less than 30 min. On the contrary, particles without BSA were unable to remove bilirubin from plasma. Thus, the attachment of albumin to the particles plays a key role in selectively reducing bilirubin levels.

Clinical outcomes and complications of peripheral nerve field stimulation in the management of refractory trigeminal pain: a systematic review and meta-analysis.

OBJECTIVE: Peripheral nerve field stimulation (PNFS) is a tool in the armamentarium of treatment options for trigeminal pain. The efficacy of this modality in mitigating trigeminal pain remains unclear. The aim of this study was to examine the existing literature on PNFS and elucidate pain score outcomes associated with its use in patients with trigeminal pain. METHODS: A systematic review and meta-analysis was performed in accordance with the PRISMA framework. The PubMed, Web of Science, and Scopus databases were queried on June 10, 2020. Studies reporting pain outcomes in more than 5 adult patients treated with PNFS for facial pain were included. The primary outcome of the study was the mean difference in the visual analog scale (VAS) score from the last follow-up to baseline, and it was analyzed by an inverse-variance, random-effect model. The risk of bias was assessed using the Newcastle-Ottawa Scale and a funnel plot. RESULTS: Of the 4597 studies screened for inclusion, 46 relevant full-text articles were assessed for eligibility. Eleven observational cohort studies from the 46 articles were found to be eligible, and reported on a total of 109 patients. In 86% (94/109) of cases, trial stimulation was successful and followed by a permanent system implantation. VAS scores improved by 75% (mean difference 6.32/10 points, 95% CI 5.38-7.27 points) compared to baseline. Seventy-six percent (42/55) of patients became medication free or required lower doses of medications. The complication rate necessitating surgical revision was estimated at 32% per procedure. CONCLUSIONS: These findings support the belief that PNFS provides effective, long-term pain control for trigeminal pain. Statistical heterogeneity was considerable across all studies. Future work should be aimed at conducting double-blind randomized controlled trials to determine the utility of PNFS for treating various forms of trigeminal pain for which limited therapeutic options exist.

Implantable Pulse Generators for Deep Brain Stimulation: Challenges, Complications, and Strategies for Practicality and Longevity.

Deep brain stimulation (DBS) represents an important treatment modality for movement disorders and other circuitopathies. Despite their miniaturization and increasing sophistication, DBS systems share a common set of components of which the implantable pulse generator (IPG) is the core power supply and programmable element. Here we provide an overview of key hardware and software specifications of commercially available IPG systems such as rechargeability, MRI compatibility, electrode configuration, pulse delivery, IPG case architecture, and local field potential sensing. We present evidence-based approaches to mitigate hardware complications, of which infection represents the most important factor. Strategies correlating positively with decreased complications include antibiotic impregnation and co-administration and other surgical considerations during IPG implantation such as the use of tack-up sutures and smaller profile devices.Strategies aimed at maximizing battery longevity include patient-related elements such as reliability of IPG recharging or consistency of nightly device shutoff, and device-specific such as parameter delivery, choice of lead configuration, implantation location, and careful selection of electrode materials to minimize impedance mismatch. Finally, experimental DBS systems such as ultrasound, magnetoelectric nanoparticles, and near-infrared that use extracorporeal powered neuromodulation strategies are described as potential future directions for minimally invasive treatment.

Active unilateral condylar hyperplasia: Assessment of the usefulness of single photon emission computed tomography

BACKGROUND: This study aims to evaluate whether the uptake difference by the condyles evaluated using single photon emission computed tomography (SPECT) examination is useful for predicting the activity of the feature and the advance of this pathology. MATERIAL AND METHODS: An observational and prospective study has been carried out on nine patients affected by unilateral condylar hyperplasia (UCH) with complete bone maturation, with a follow-up over 18 months. At the beginning of the study, a test-battery was conducted including dental casts, articular examination, teleradiography and cephalometry, computed tomography and SPECT, creating two groups of patients from a difference in uptake between both condyles greater than 10% over the follow-up period. Evolution of data obtained with the rest of the diagnostic tests were compared to confirm UCH activity predicted by SPECT. RESULTS: The comparison of both groups did not show hardly any significant differences, with little clinical significance. Deviation of the mandibular line, the size of the branches or condyles behaved similarly in both study groups. CONCLUSIONS: From the data obtained in our study, we can conclude that the use of the difference in uptake between both condyles by applying the SPECT technique is not a valid approach for predicting clinical activity in cases of UCH

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Desarrollo de modelo experimental animal de peritonitis bacteriana / Development of animal experimental model for bacterial peritonitis

OBJETIVO: Desarrollar un modelo de sepsis abdominal en animal de experimentación. MATERIAL Y MÉTODOS: Se utilizan ratas Sprague-Dawley(R), machos de 5 semanas con pesos entre 270-280 g en el momento de la inoculación (N=39). Inicialmente se realiza un estudio piloto (N=9), distribuyéndolas en 3 grupos (3/3/3) con inóculo de 1cc de Escherichia coli ATCC 25922 intraperitoneal en concentraciones de 10E8, 10E9 y 10E10 UFC. En un segundo estudio (N=6) con distribución en dos grupos (3/3) se utilizan 1cc una concentración de E. coli 10E10 UFC que se diluyen en 10 y 15 ml de agua destilada para su inoculación. Por último se inicia un ensayo experimental con aleatorización de 24 ratas en tres grupos de tratamiento tras la infección intraperitoneal: Grupo I con suero fisiológico (N=6), Grupo II con antibiótico (ceftriaxona) (N=9), Grupo III con antibiótico más adyuvante (ceftriaxona más alicina) (N=9). Se realizan muestras microbiológicas de sangre y líquido peritoneal, así como estudio histopatológico de órganos intraperitoneales (hígado, diafragma y peritoneo). RESULTADOS: Se observa muerte en el 100% de las ratas infectadas con la concentración de E. coli 10E10 UFC con la dilución de 15 ml de agua destilada y sin antibiótico. El hemocultivo y cultivo de líquido peritoneal es positivo a la misma cepa en todas ellas. Se observa la formación de abscesos en la superficie del hígado e infiltración por polimorfonucleares en los tejidos. CONCLUSIÓN: Se establece que la dosis letal de E. coli es 10E10 UFC diluida en 15 ml agua destilada en inyección intraperitoneal

OBJECTIVE: The aim of the study was to develop a model of abdominal sepsis in the experimental animal. MATERIAL AND METHODS: Sprague-Dawley male rats of 5 weeks (N=39) were used. Initially, a pilot study (N = 9) was performed and distributed in 3 groups with 1cc inoculum of Escherichia coli ATCC 25922 intraperitoneally at concentrations of 10E8, 10E9 and 10E10 CFU. Subsequently, concentrations of 10E10 CFU are used in two groups of 3 rats with dilutions of 10 cc and 15 cc of distilled water respectively. Finally, a randomized trial of 24 rats was started in three treatment groups after intraperitoneal infection: Group I with physiological serum (N = 6), Group II with ceftriaxone (N = 9), Group III with ceftriaxone plus allicin (N = 9). Microbiological samples of blood and peritoneal fluid were made, as well as histopathological study of intraperitoneal organs (liver, diaphragm and peritoneum). RESULTS: Death of 100% of the rats infected with 10E10 E. coli UFC concentration with the dilution of 15 ml of distilled water and without antibiotic was oberved. The blood culture and peritoneal fluid culture was positive for the same strain in all of them. The formation of abscesses on the liver surface and polymorphonuclear infiltration in tissues were observed. CONCLUSION: The lethal dose of E. coli is 10E10 CFU diluted in 15 cc distilled water by intraperitoneal injection

Complete resolution of postherpetic neuralgia following pallidotomy: case report.

The authors report on a female patient with left-dominant Parkinson's disease with motor fluctuations and levodopa-induced dyskinesias and comorbid postherpetic neuralgia (PHN), who underwent a right-sided pallidotomy. Besides a substantial improvement in her Parkinson's symptoms, she reported an immediate and complete disappearance of PHN. This neuralgia had been long-standing, pharmacologically refractory, and severe (preoperative Brief Pain Inventory [BPI] pain severity score of 8.0, BPI pain interference score of 7.3, short-form McGill Pain Questionnaire sensory pain rating index of 7 and affective pain rating index of 10, Present Pain Intensity rank value of 4, and visual analog scale score of 81 mm; all postoperative scores were 0). She continued to be pain free at 16 months postoperatively.This peculiar finding adds substantially to the largely unrecognized evidence for the role of the pallidum in pain processing, based on previous electrophysiological, metabolic, anatomical, pharmacological, and clinical observations. Therefore, the potential of the pallidum as a neurosurgical target for neuropathic pain warrants further investigation.

The Global End-Diastolic Volume (GEDV) Could Be More Appropiate to Fluid Management Than Central Venous Pressure (CVP) During Closed Hyperthermic Intrabdominal Chemotherapy with CO2 Circulation.

BACKGROUND: Closed hyperthermic intraperitoneal chemotherapy (HIPEC) may increase abdominal pressure and effects of hemodynamic changes due to maintenance hyperthermia. Our aim was to analyze the safety and effectiveness of our closed technique with CO2 circulation in management fluid status and hemodynamic parameters by means of cardiac preload control measured by Global End Diastolic Values (GEDV) and a gas exchanger. MATERIAL AND METHODS: A Pilot Clinical Study that included 18 advanced ovarian cancer patients undergoing citoreductive surgery and HIPEC. We used a closed-perfusion system (PRS Combat®) that includes CO2 circulation and a gas exchanger. Transpulmonary thermodilutions and hemodynamic measurements (PiCCO2®) were performed after citoreductive surgery (Pre-HIPEC); At half time of the HIPEC (Intra-HIPEC); After HIPEC (Post-HIPEC). RESULTS: No significant hemodynamic measurements changes in the three thermodilutions values of Cardiac Index (CI) (p = 0.227), Global End Diastolic Values (GEVD) (p = 0.966), Stroke Volume Variation (SVV) (p = 0,884) and Systemic Vascular Resistance Index (SVRI) (p = 0.082). No correlation between central venous pressure (CVP) and GEDV (Pre-HIPEC: r = 0.164, p = 0.211; Intra-HIPEC: r = 0.015, p = 0.900; Post-HIPEC: r = 0.018, p = 0.890). There was better correlation between GEDV and CI (Pre-HIPEC: r = 0.432, p = 0.071; Intra-HIPEC: r = 0.418, p = 0.074; Post-HIPEC: r = 0.411, p = 0.080). CONCLUSIONS: Closed intrabdominal chemotherapy with CO2 circulation model may be a safe model for HIPEC by means of a gas exchanger. GEDV and its changes significantly correlated to CI, and not observed for CVP. GEDV values may be more appropriate for monitoring cardiac preload, blood loss limitation and to predict changes in intravascular volume status during intraperitoneal chemotherapy.

Ischemic femoral head osteonecrosis in a piglet model causes three dimensional decrease in acetabular coverage.

Legg-Calve-Perthes disease (LCPD) is a childhood form of ischemic osteonecrosis marked by development of severe femoral head deformity and premature osteoarthritis. The pathogenesis of femoral head deformity has been studied extensively using a piglet model of ischemic osteonecrosis, however, accompanying acetabular changes have not been investigated. The purpose of this study was to determine if acetabular changes accompany femoral head deformity in a well-established piglet model of LCPD and to define the acetabular changes using three dimensional computed tomography (3-D CT) and modeling. Twenty-four piglets were surgically induced with ischemic osteonecrosis on the right side. The contralateral hip was used as control. At 8 weeks postoperative, pelvi were retrieved and imaged with CT. Custom software was used to measure acetabular morphologic parameters on 3-D CT images. Moderate to severe femoral head deformities were present in all animals. Acetabula with accompanying femoral head deformity had a significant decrease in acetabular version and tilt (p < 0.001) and in coverage angle in the superior, posterior, and inferior quadrants (p < 0.05). These findings indicate that the development of femoral head deformity following ischemic osteonecrosis produces specific and predictable changes to the shape of the acetabulum. Acetabular changes described in patients with LCPD were observed in the piglet model. This model may serve as a valuable tool to elucidate the relationship between femoral head and acetabular deformities. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 36:1173-1177, 2018.

Factors affecting the distribution of haemosporidian parasites within an oceanic island.

Understanding how different ecological and evolutionary processes influence the distribution of pathogens within the environment is important from many perspectives including wildlife epidemiology, evolutionary ecology and conservation. The simultaneous use of ecological and evolutionary frameworks can enhance our conceptual understanding of host-parasite interactions, however such studies are rare in the wild. Using samples from 12 bird species caught across all habitats existing on an oceanic island, we evaluated how environmental variables, parasite host specificity and parasite phylogenetic relationships determine the distribution and prevalence of haemosporidians (Haemoproteus, Plasmodium and Leucocytozoon) in the wild living avifauna. Differences were found in the prevalence of Plasmodium, but not Leucocytozoon, strains between habitats. The warmest temperature best predicted Plasmodium prevalence in the low altitude habitats, which had the highest incidence of Plasmodium. The prevalence of Leucocytozoon lineages was associated with natural factors, i.e. rainfall, temperature and habitat, but the two most important predictors (from model averaging) for models of Leucocytozoon were anthropogenic: poultry farms and distance to a water reservoir. We found no relationship between local (Tenerife, Canary Islands) versus global host range indices (which assess the diversity of hosts that a parasite is observed to infect), thus global generalist lineages do not behave in the same way on Tenerife (i.e. they infected less avian hosts than was expected). Phylogenetic analysis revealed that the most abundant haemosporidians on Tenerife grouped with lineages found in African host species. Our data indicate that climatic and anthropogenic factors, plus proximity to the African mainland, are the main factors influencing the presence and distribution of avian haemosporidians on Tenerife. Future climate projections for the archipelago foresee significant temperature increases which would, given our results, increase rates of Plasmodium infection in bird species in all habitats. Such patterns could be of concern if those increase mortality rates in the unique avifauna of these islands.

Consequences of Team Job Demands: Role Ambiguity Climate, Affective Engagement, and Extra-Role Performance.

In the absence of clearly established procedures in the workplace, employees will experience a negative affective state. This situation influences their well-being and their intention to behave in ways that benefit the organization beyond their job demands. This impact is more relevant on teamwork where members share the perception of ambiguity through emotional contagion (role ambiguity climate). In the framework of the job demands-resources model, the present study analyzes how high levels of role ambiguity climate can have such an effect to reduce employee affective engagement. Over time it has been associated with negative results for the organization due to a lack of extra-role performance. The sample included 706 employees from a multinational company, who were divided into 11 work teams. In line with the formulated hypotheses, the results confirm the negative influence of the role ambiguity climate on extra-role performance, and the mediated effect of affective engagement in the relationship between the role ambiguity climate and extra-role performance. These findings indicate that the role ambiguity climate is related to the adequate or inadequate functioning of employees within a work context.

Population history, gene flow, and bottlenecks in island populations of a secondary seed disperser, the southern grey shrike (Lanius meridionalis koenigi).

Studying the population history and demography of organisms with important ecological roles can aid understanding of evolutionary processes at the community level and inform conservation. We screened genetic variation (mtDNA and microsatellite) across the populations of the southern grey shrike (Lanius meridionalis koenigi) in the Canary Islands, where it is an endemic subspecies and an important secondary seed disperser. We show that the Canarian subspecies is polyphyletic with L. meridionalis elegans from North Africa and that shrikes have colonized the Canary Islands from North Africa multiple times. Substantial differences in genetic diversity exist across islands, which are most likely the product of a combination of historical colonization events and recent bottlenecks. The Eastern Canary Islands had the highest overall levels of genetic diversity and have probably been most recently and/or frequently colonized from Africa. Recent or ongoing bottlenecks were detected in three of the islands and are consistent with anecdotal evidence of population declines due to human disturbance. These findings are troubling given the shrike's key ecological role in the Canary Islands, and further research is needed to understand the community-level consequences of declines in shrike populations. Finally, we found moderate genetic differentiation among populations, which largely reflected the shrike's bottleneck history; however, a significant pattern of isolation-by-distance indicated that some gene flow occurs between islands. This study is a useful first step toward understanding how secondary seed dispersal operates over broad spatial scales.