Novel Cocrystal Structures of Peptide Antagonists Bound to the Human Melanocortin Receptor 4 Unveil Unexplored Grounds for Structure-Based Drug Design.

Melanocortin 4 receptor (MC4-R) antagonists are actively sought for treating cancer cachexia. We determined the structures of complexes with PG-934 and SBL-MC-31. These peptides differ from SHU9119 by substituting His6 with Pro6 and inserting Gly10 or Arg10. The structures revealed two subpockets at the TM7-TM1-TM2 domains, separated by N2857.36. Two peptide series based on the complexed peptides led to an antagonist activity and selectivity SAR study. Most ligands retained the SHU9119 potency, but several SBL-MC-31-derived peptides significantly enhanced MC4-R selectivity over MC1-R by 60- to 132-fold. We also investigated MC4-R coupling to the K+ channel, Kir7.1. Some peptides activated the channel, whereas others induced channel closure independently of G protein coupling. In cell culture studies, channel activation correlated with increased feeding, while a peptide with Kir7.1 inhibitory activity reduced eating. These results highlight the potential for targeting the MC4-R:Kir7.1 complex for treating positive and restrictive eating disorders.

Inhibition of the melanocortin-3 receptor (MC3R) causes generalized sensitization to anorectic agents.

The melanocortin-3 receptor (MC3R) acts presynaptically to regulate GABA release from agouti-related protein (AgRP) nerve terminals and thus may be a negative regulator of multiple circuits involved in feeding behavior and energy homeostasis. Here, we examined the role of MC3R in regulating the response to various anorexigenic agents. Our findings reveal that genetic deletion or pharmacological inhibition of MC3R improves the dose responsiveness to Glucagon-like peptide 1 (GLP1) agonists, as assayed by inhibition of food intake and weight loss. An enhanced anorectic response to other agents, including the acute satiety factors peptide YY (PYY3-36) and cholecystokinin (CCK) and the long-term adipostatic factor, leptin, demonstrated that increased sensitivity to anorectic agents is a generalized result of MC3R antagonism. Enhanced neuronal activation in multiple nuclei, including ARH, VMH, and DMH, was observed using Fos immunohistochemistry following low-dose liraglutide in MC3R knockout mice (Mc3r-/-), supporting the hypothesis that the MC3R is a negative regulator of circuits regulating multiple aspects of feeding behavior. The enhanced anorectic response in Mc3r -/- mice after administration of GLP1 analogs was also independent of the incretin effects and malaise induced by GLP1R analogs, suggesting that MC3R antagonists may have value in enhancing the dose-response range of obesity therapeutics.

Thermal acclimation and habitat-dependent differences in temperature robustness of a crustacean motor circuit.

Introduction: At the cellular level, acute temperature changes alter ionic conductances, ion channel kinetics, and the activity of entire neuronal circuits. This can result in severe consequences for neural function, animal behavior and survival. In poikilothermic animals, and particularly in aquatic species whose core temperature equals the surrounding water temperature, neurons experience rather rapid and wide-ranging temperature fluctuations. Recent work on pattern generating neural circuits in the crustacean stomatogastric nervous system have demonstrated that neuronal circuits can exhibit an intrinsic robustness to temperature fluctuations. However, considering the increased warming of the oceans and recurring heatwaves due to climate change, the question arises whether this intrinsic robustness can acclimate to changing environmental conditions, and whether it differs between species and ocean habitats. Methods: We address these questions using the pyloric pattern generating circuits in the stomatogastric nervous system of two crab species, Hemigrapsus sanguineus and Carcinus maenas that have seen a worldwide expansion in recent decades. Results and discussion: Consistent with their history as invasive species, we find that pyloric activity showed a broad temperature robustness (>30°C). Moreover, the temperature-robust range was dependent on habitat temperature in both species. Warm-acclimating animals shifted the critical temperature at which circuit activity breaks down to higher temperatures. This came at the cost of robustness against cold stimuli in H. sanguineus, but not in C. maenas. Comparing the temperature responses of C. maenas from a cold latitude (the North Sea) to those from a warm latitude (Spain) demonstrated that similar shifts in robustness occurred in natural environments. Our results thus demonstrate that neuronal temperature robustness correlates with, and responds to, environmental temperature conditions, potentially preparing animals for changing ecological conditions and shifting habitats.

Impacts of artificial light at night on the early life history of two ecosystem engineers.

Sessile marine invertebrates play a vital role as ecosystem engineers and in benthic-pelagic coupling. Most benthic fauna develop through larval stages and the importance of natural light cycles for larval biology and ecology is long-established. Natural light-dark cycles regulate two of the largest ocean-scale processes that are fundamental to larvae's life cycle: the timing of broadcast spawning for successful fertilization and diel vertical migration for foraging and predator avoidance. Given the reliance on light and the ecological role of larvae, surprisingly little is known about the impacts of artificial light at night (ALAN) on the early life history of habitat-forming species. We quantified ALAN impacts on larval performance (survival, growth, development) of two cosmopolitan ecosystem engineers in temperate marine ecosystems, the mussel Mytilus edulis and the barnacle Austrominius modestus. Higher ALAN irradiance reduced survival in both species (57% and 13%, respectively). ALAN effects on development and growth were small overall, and different between species, time-points and parentage. Our results show that ALAN adversely affects larval survival and reiterates the importance of paternal influence on offspring performance. ALAN impacts on the early life stages of ecosystem engineering species have implications not only for population viability but also the ecological communities that these species support. This article is part of the theme issue 'Light pollution in complex ecological systems'.

Targeting the central melanocortin system for the treatment of metabolic disorders.

A large body of preclinical and clinical data shows that the central melanocortin system is a promising therapeutic target for treating various metabolic disorders such as obesity and cachexia, as well as anorexia nervosa. Setmelanotide, which functions by engaging the central melanocortin circuitry, was approved by the FDA in 2020 for use in certain forms of syndromic obesity. Furthermore, the FDA approvals in 2019 of two peptide drugs targeting melanocortin receptors for the treatment of generalized hypoactive sexual desire disorder (bremelanotide) and erythropoietic protoporphyria-associated phototoxicity (afamelanotide) demonstrate the safety of this class of peptides. These approvals have also renewed excitement in the development of therapeutics targeting the melanocortin system. Here, we review the anatomy and function of the melanocortin system, discuss progress and challenges in developing melanocortin receptor-based therapeutics, and outline potential metabolic and behavioural disorders that could be addressed using pharmacological agents targeting these receptors.

Aspectos asistenciales de la infección periamigdalina antes y durante la pandemia de COVID-19 / Healthcare aspects of peritonsillar infection before and during the COVID-19 pandemic

Introducción: Este estudio trata de valorar la repercusión de la pandemia sobre la incidencia y la evolución clínica de la infección periamigdalina (IPA).Material y métodosRevisamos en un seguimiento longitudinal y descriptivo retrospectivo las circunstancias de los pacientes atendidos durante 5 años, de 2017 a 2021, en dos hospitales, uno comarcal y otro terciario. Se registraron variables relacionadas con la patología de base, antecedentes de amigdalitis, tiempo de evolución, visitas previas en Atención Primaria, hallazgos en el diagnóstico, relación absceso/flemón y días de estancia hospitalaria.ResultadosDe 2017 a 2019 la incidencia de la enfermedad osciló entre 14 y 16 casos/100.000 habitantes-año, pero en 2020 se redujo a 9,3, un 43% menos. Los pacientes con IPA que consultaron en pandemia generaron pocas visitas previas en servicios de Atención Primaria, presentaron mayor severidad de los síntomas y mayor demora en el diagnóstico. Además, hubo más abscesos que flemones y la necesidad de ingreso hospitalario superior a 24h fue del 66%. Apenas hubo causalidad con amigdalitis agudas, aunque el 66% de los pacientes padecía amigdalitis de repetición, y el 71% patología concomitante. Todos estos hallazgos mostraron diferencias estadísticamente significativas respecto a los casos prepandemia.ConclusionesLa protección de la transmisión aérea, el distanciamiento social y el confinamiento adoptados en nuestro país son medidas que han podido modificar la evolución de la IPA, con una incidencia muy inferior, un período de recuperación mayor y mínima relación con amigdalitis aguda. (AU)

Introduction: This study assessed if the healthcare system overload and the organizational changes made in response to COVID-19 may be having an impact on clinical and epidemiological characteristics of the peritonsillar infection (PTI).Materials and methodsIn a retrospective longitudinal and descriptive follow-up, we reviewed the circumstances of the patients attended during 5 years, from 2017 to 2021, in two hospitals, one regional and other tertiary. Variables related to underlying pathology, history of tonsillitis, time of evolution, previous visits to Primary Care, diagnostic findings, abscess/phlegmon ratio, and length of hospital stay were recorded.ResultsFrom 2017 to 2019, the incidence of the disease ranged between 14 and 16 cases/100,000 inhabitants-year, and decreased to 9.3 in 2020, a 43% less. Patients with PTI consulting in pandemic time were visited much less often in Primary Care services. They showed a greater severity of symptoms and the period of time between their appearance and diagnosis was longer. Additionally, there were more abscesses and the need for hospital admission greater than 24h was 66%. There was hardly a causal relationship with acute tonsillitis, although 66% of the patients evidenced history of recurrent tonsillitis, and 71% concomitant pathology. All these findings showed statistically significant differences with the pre-pandemic cases.ConclusionsThe protection of airborne transmission, the social distancing and the lockdown adopted in our country are measures that seem having been able to modify the evolution of PTI, with a much lower incidence, a longer recovery period and a minimal relationship with acute tonsillitis. (AU)

Healthcare aspects of peritonsillar infection before and during the COVID-19 pandemic.

INTRODUCTION: This study assessed if the healthcare system overload and the organizational changes made in response to COVID-19 may be having an impact on clinical and epidemiological characteristics of the peritonsillar infection (PTI). MATERIALS AND METHODS: In a retrospective longitudinal and descriptive follow-up, we reviewed the circumstances of the patients attended during 5 years, from 2017 to 2021, in two hospitals, one regional and other tertiary. Variables related to underlying pathology, history of tonsillitis, time of evolution, previous visits to Primary Care, diagnostic findings, abscess/phlegmon ratio, and length of hospital stay were recorded. RESULTS: From 2017 to 2019, the incidence of the disease ranged between 14 and 16 cases/100,000 inhabitants-year, and decreased to 9.3 in 2020, a 43% less. Patients with PTI consulting in pandemic time were visited much less often in Primary Care services. They showed a greater severity of symptoms and the period of time between their appearance and diagnosis was longer. Additionally, there were more abscesses and the need for hospital admission greater than 24h was 66%. There was hardly a causal relationship with acute tonsillitis, although 66% of the patients evidenced history of recurrent tonsillitis, and 71% concomitant pathology. All these findings showed statistically significant differences with the pre-pandemic cases. CONCLUSIONS: The protection of airborne transmission, the social distancing and the lockdown adopted in our country are measures that seem having been able to modify the evolution of PTI, with a much lower incidence, a longer recovery period and a minimal relationship with acute tonsillitis.

The unique structural characteristics of the Kir 7.1 inward rectifier potassium channel: a novel player in energy homeostasis control.

The inward rectifier potassium channel Kir7.1, encoded by the KCNJ13 gene, is a tetramer composed of two-transmembrane domain-spanning monomers, closer in homology to Kir channels associated with potassium transport such as Kir1.1, 1.2, and 1.3. Compared with other channels, Kir7.1 exhibits small unitary conductance and low dependence on external potassium. Kir7.1 channels also show a phosphatidylinositol 4,5-bisphosphate (PIP2) dependence for opening. Accordingly, retinopathy-associated Kir7.1 mutations mapped at the binding site for PIP2 resulted in channel gating defects leading to channelopathies such as snowflake vitreoretinal degeneration and Leber congenital amaurosis in blind patients. Lately, this channel's role in energy homeostasis was reported due to the direct interaction with the melanocortin type 4 receptor (MC4R) in the hypothalamus. As this channel seems to play a multipronged role in potassium homeostasis and neuronal excitability, we will discuss what is predicted from a structural viewpoint and its possible implications for hunger control.

Thallium poisoning: a case report.

Thallium poisoning is usually accidental. We present a case of a 51-year-old woman who was evaluated in June 2018 for myalgia, vertigo, asthenia, and abdominal pain. Physical examination revealed temporal-spatial disorientation, jaundice, and asterixis. The laboratory reported the following: bilirubin, 10.3 mg/dL; aspartate transaminase, 78 U/L; alanine transaminase, 194 U/L; albumin, 2.3 g/dL; prothrombin time, 40%; and platelet count, 60,000/mm3. Serology performed for hepatitis A, B, and C; Epstein-Barr virus; cytomegalovirus; and human immunodeficiency virus was negative, and a collagenogram was negative. Physical reevaluation revealed alopecia on the scalp, armpits, and eyebrows; macules on the face; plantar hyperkeratosis; and ulcers on the lower limbs. Tests for lead, arsenic, copper, and mercury were carried out, which were normal; however, elevated urinary thallium (540 µg/g; range, 0.4-10 µg/g) was observed. The patient was treated with ᴅ-penicillamine 1,000 mg/day and recovered her urinary thallium levels were within normal range at annual follow-up. Thallium poisoning is extremely rare and can be fatal in small doses. An adequate clinical approach can facilitate early diagnosis.

[Healthcare aspects of peritonsillar infection before and during the COVID-19 pandemic]. / Aspectos asistenciales de la infección periamigdalina antes y durante la pandemia de COVID-19.

Introduction: This study assessed if the healthcare system overload and the organizational changes made in response to COVID-19 may be having an impact on clinical and epidemiological characteristics of the peritonsillar infection (PTI). Materials and methods: In a retrospective longitudinal and descriptive follow-up, we reviewed the circumstances of the patients attended during 5 years, from 2017 to 2021, in two hospitals, one regional and other tertiary. Variables related to underlying pathology, history of tonsillitis, time of evolution, previous visits to Primary Care, diagnostic findings, abscess/phlegmon ratio, and length of hospital stay were recorded. Results: From 2017 to 2019, the incidence of the disease ranged between 14 and 16 cases/100,000 inhabitants-year, and decreased to 9.3 in 2020, a 43% less. Patients with PTI consulting in pandemic time were visited much less often in Primary Care services. They showed a greater severity of symptoms and the period of time between their appearance and diagnosis was longer. Additionally, there were more abscesses and the need for hospital admission greater than 24 h was 66%. There was hardly a causal relationship with acute tonsillitis, although 66% of the patients evidenced history of recurrent tonsillitis, and 71% concomitant pathology. All these findings showed statistically significant differences with the pre-pandemic cases. Conclusions: The protection of airborne transmission, the social distancing and the lockdown adopted in our country are measures that seem having been able to modify the evolution of PTI, with a much lower incidence, a longer recovery period and a minimal relationship with acute tonsillitis.

Experiencias subjetivas del personal de salud durante la emergencia sanitaria en Uruguay / Experiences of health personnel during the health emergency in Uruguay / Vivências subjetivas dos trabalhadores de saúde na emergência sanitária en Uruguay

La emergencia sanitaria COVID-19 impactó en los/as trabajadores de salud, dejando en evidencia: el malestar subjetivo y altos índices de ansiedad y depresión. El objetivo del presente trabajo es analizar las experiencias y vivencias de trabajadores/as de la salud durante la pandemia. La misma se realizó a partir del análisis de las respuestas obtenidas en la pregunta abierta del formulario autoadministrado del proyecto Héroes Uruguay. La población objetivo fue el personal de los servicios de salud integrados al Sistema Nacional Integrado de Salud en los tres niveles de atención. Las respuestas fueron agrupadas y categorizadas en base a su frecuencia. La categoría condiciones de trabajo fue la temática más mencionada, seguida de organización del trabajo y vivencias. Realizamos otra categorización sobre los sentidos subjetivos durante la pandemia, nueve categorías son las frecuentes, siendo el 86% de los sentidos subjetivos: ansiedad y estrés, miedo, cansancio, no apoyo social y sobrecarga son los más mencionados. Los resultados muestran que la mayoría de las respuestas remite a las condiciones y a la organización del trabajo, se trata de dimensiones claves en la salud del trabajador, en su entorno, y en los procesos de asistencia al paciente y su familia. Este estudio nos permite afirmar la importancia a nivel organizacional y de políticas de salud, de generar entornos laborales seguros y saludables. La emergencia sanitaria generada por el COVID 19, expuso y agudizó la tensión de los sistemas sanitarios y su impacto en la salud y bienestar del personal.

The COVID-19 health emergency impacted health workers, revealing: subjective discomfort and high rates of anxiety and depression. The objective of this work is to analyze the experiences of health workers during the pandemic. It was carried out from the analysis of the answers obtained in the open question of the self-administered form of the Héroes Uruguay project. The target population was the staff of the health services integrated into the National Integrated Health System at the three levels of care. The responses were grouped and categorized based on recurring themes. The working conditions category was the most mentioned theme, followed by work organization and experiences. We carry out another categorization of the subjective senses during the pandemic, nine categories are the most frequent, with 86% of the subjective senses: anxiety and stress, fear, tiredness, lack of social support and overload are the most mentioned. The results show that most of the answers refer to the conditions and organization of work, these are key dimensions in the worker's health, in his environment, and in the patient assisted and his family. This study allows us to affirm the importance at the organizational and health policy level of generating safe and healthy work environments. The health emergency generated by COVID 19 exposed and exacerbated the tension in health systems and its impact on the health and well-being of personnel.

A emergência sanitária da COVID-19 impactou os trabalhadores da saúde, revelando: desconforto subjetivo e altos índices de ansiedade e depressão. O objetivo deste trabalho é analisar as vivências dos trabalhadores da saúde durante a pandemia. Foi realizada a partir da análise das respostas obtidas na questão aberta do formulário autoaplicável do projeto Héroes Uruguai. A população alvo foram os trabalhadores dos serviços de saúde integrados no Sistema Único de Saúde Integrado nos três níveis de cuidados. As respostas foram agrupadas e categorizadas com base em temas recorrentes. A categoria condições de trabalho foi o tema mais citado, seguido de organização do trabalho e experiências. Realizamos outra categorização dos sentidos subjetivos durante a pandemia, nove categorias são as mais frequentes, com 86% dos sentidos subjetivos: ansiedade e estresse, medo, cansaço, falta de apoio social e sobrecarga são os mais citados. Os resultados mostram que a maioria das respostas se refere às condições e organização do trabalho, dimensões fundamentais na saúde do trabalhador, em seu ambiente, e no paciente assistido e sua família. Este estudo permite afirmar a importância a nível organizacional e da política de saúde de gerar ambientes de trabalho seguros e saudáveis. A emergência de saúde gerada pelo COVID 19 expôs e exacerbou a tensão nos sistemas de saúde e seu impacto na saúde e bem-estar do pessoal.

European Lobster Larval Development and Fitness Under a Temperature Gradient and Ocean Acidification.

Climate change combined with anthropogenic stressors (e.g. overfishing, habitat destruction) may have particularly strong effects on threatened populations of coastal invertebrates. The collapse of the population of European lobster (Homarus gammarus) around Helgoland constitutes a good example and prompted a large-scale restocking program. The question arises if recruitment of remaining natural individuals and program-released specimens could be stunted by ongoing climate change. We examined the joint effect of ocean warming and acidification on survival, development, morphology, energy metabolism and enzymatic antioxidant activity of the larval stages of the European lobster. Larvae from four independent hatches were reared from stage I to III under a gradient of 10 seawater temperatures (13-24°C) combined with moderate (∼470 µatm) and elevated (∼1160 µatm) seawater pCO2 treatments. Those treatments correspond to the shared socio-economic pathways (SSP), SSP1-2.6 and SSP5-8.5 (i.e. the low and the very high greenhouse gas emissions respectively) projected for 2100 by the Intergovernmental Panel on Climate Change. Larvae under the elevated pCO2 treatment had not only lower survival rates, but also significantly smaller rostrum length. However, temperature was the main driver of energy demands with increased oxygen consumption rates and elemental C:N ratio towards warmer temperatures, with a reducing effect on development time. Using this large temperature gradient, we provide a more precise insight on the aerobic thermal window trade-offs of lobster larvae and whether exposure to the worst hypercapnia scenario may narrow it. This may have repercussions on the recruitment of the remaining natural and program-released specimens and thus, in the enhancement success of future lobster stocks.

A framework to understand the role of biological time in responses to fluctuating climate drivers.

Understanding biological responses to environmental fluctuations (e.g. heatwaves) is a critical goal in ecology. Biological responses (e.g. survival) are usually measured with respect to different time reference frames, i.e. at specific chronological times (e.g. at specific dates) or biological times (e.g. at reproduction). Measuring responses on the biological frame is central to understand how environmental fluctuation modifies fitness and population persistence. We use a framework, based on partial differential equations (PDEs) to explore how responses to the time scale and magnitude of fluctuations in environmental variables (= drivers) depend on the choice of reference frame. The PDEs and simulations enabled us to identify different components, responsible for the phenological and eco-physiological effects of each driver on the response. The PDEs also highlight the conditions when the choice of reference frame affects the sensitivity of the response to a driver and the type of join effect of two drivers (additive or interactive) on the response. Experiments highlighted the importance of studying how environmental fluctuations affect biological time keeping mechanisms, to develop mechanistic models. Our main result, that the effect of the environmental fluctuations on the response depends on the scale used to measure time, applies to both field and laboratory conditions. In addition, our approach, applied to experimental conditions, can helps us quantify how biological time mediates the response of organisms to environmental fluctuations.

Demonstration of a Common DPhe7 to DNal(2')7 Peptide Ligand Antagonist Switch for Melanocortin-3 and Melanocortin-4 Receptors Identifies the Systematic Mischaracterization of the Pharmacological Properties of Melanocortin Peptides.

Melanocortin peptides containing a 3-(2-naphthyl)-d-alanine residue in position 7 (DNal(2')7), reported as melanocortin-3 receptor (MC3R) subtype-specific agonists in two separate publications, were found to lack significant MC3R agonist activity. The cell lines used at the University of Arizona for pharmacological characterization of these peptides, consisting of HEK293 cells stably transfected with human melanocortin receptor subtypes MC1R, MC3R, MC4R, or MC5R, were then obtained and characterized by quantitative polymerase chain reaction (PCR). While the MC1R cell line correctly expressed only hMCR1, the three other cell lines were mischaracterized with regard to receptor subtype expression. The demonstration that a 3-(2-naphthyl)-d-alanine residue in position 7, irrespective of the melanocortin peptide template, results primarily in the antagonism of MC3R and MC4R then allowed us to search the published literature for additional errors. The erroneously characterized DNal(2')7-containing peptides date back to 2003; thus, our analysis suggests that systematic mischaracterization of the pharmacological properties of melanocortin peptides occurred.

The impact of the COVID-19 pandemic on the mental health of healthcare workers: study protocol for the COVID-19 HEalth caRe wOrkErS (HEROES) study.

BACKGROUND: Preliminary country-specific reports suggest that the COVID-19 pandemic has a negative impact on the mental health of the healthcare workforce. In this paper, we summarize the protocol of the COVID-19 HEalth caRe wOrkErS (HEROES) study, an ongoing, global initiative, aimed to describe and track longitudinal trajectories of mental health symptoms and disorders among health care workers at different phases of the pandemic across a wide range of countries in Latin America, Europe, Africa, Middle-East, and Asia. METHODS: Participants from various settings, including primary care clinics, hospitals, nursing homes, and mental health facilities, are being enrolled. In 26 countries, we are using a similar study design with harmonized measures to capture data on COVID-19 related exposures and variables of interest during two years of follow-up. Exposures include potential stressors related to working in healthcare during the COVID-19 pandemic, as well as sociodemographic and clinical factors. Primary outcomes of interest include mental health variables such as psychological distress, depressive symptoms, and posttraumatic stress disorders. Other domains of interest include potentially mediating or moderating influences such as workplace conditions, trust in the government, and the country's income level. RESULTS: As of August 2021, ~ 34,000 health workers have been recruited. A general characterization of the recruited samples by sociodemographic and workplace variables is presented. Most participating countries have identified several health facilities where they can identify denominators and attain acceptable response rates. Of the 26 countries, 22 are collecting data and 2 plan to start shortly. CONCLUSIONS: This is one of the most extensive global studies on the mental health of healthcare workers during the COVID-19 pandemic, including a variety of countries with diverse economic realities and different levels of severity of pandemic and management. Moreover, unlike most previous studies, we included workers (clinical and non-clinical staff) in a wide range of settings.

A state-space approach to understand responses of organisms, populations and communities to multiple environmental drivers.

Understanding the response of biotic systems to multiple environmental drivers is one of the major concerns in ecology. The most common approach in multiple driver research includes the classification of interactive responses into categories (antagonistic, synergistic). However, there are situations where the use of classification schemes limits our understanding or cannot be applied. Here, we introduce and explore an approach that allows us to better appreciate variability in responses to multiple drivers. We then apply it to a case, comparing effects of heatwaves on performance of a cold-adapted species and a warm-adapted competitor. The heatwaves had a negative effect on the native (but not on the exotic) species and the approach highlighted that the exotic species was less responsive to multivariate environmental variation than the native species. Overall, we show how the proposed approach can enhance our understanding of variation in responses due to different driver intensities, species, genotypes, ontogeny, life-phases or among spatial scales at any level of biological organization.

Noisy waters can influence young-of-year lobsters' substrate choice and their antipredatory responses.

Offshore human activities lead to increasing amounts of underwater noise in coastal and shelf environments, which may affect commercially-important benthic invertebrate groups like the re-stocked Helgoland European lobster (Homarus gammarus) in the German Bight (North Sea). It is crucial to understand the impact tonal low-frequency noises, like maritime transport and offshore energy operations, may have on substrate choice and lobsters' behavior to assess potential benefits or bottlenecks of new hard-substrate artificial offshore environments that become available. In this study, we investigated the full factorial effect of a tonal low-frequency noise and predator presence on young-of-year (YOY) European lobsters' in a diurnal and nocturnal experiment. Rocks and European oyster shells (Ostrea edulis) were offered as substrate to YOY lobsters for 3 h. Video recordings (n = 134) allowed the identification of lobsters' initial substrate choice, diel activity and key behaviors (peeking, shelter construction, exploration and hiding). To ensure independence, YOY lobsters in the intermolt stage were randomly selected and assigned to the experimental tanks and used only once. We provide the first evidence that stressors alone, and in combination, constrain YOY lobsters' initial substrate choice towards rocks. During nighttime, the joint effect of exposure to a constant low-frequency noise and predator presence decreased antipredator behavior (i.e., hiding) and increased exploration behavior. Noise may thus interfere with YOY lobsters' attention and decision-making processes. This outcome pinpoints that added tonal low-frequency noise in the environment have the potential to influence the behavior of early-life stages of European lobsters under predator pressure and highlights the importance of including key benthic invertebrates' community relationships in anthropogenic noise risk assessments. Among others, effects of noise must be taken into consideration in plans involving the multi-use of any offshore area for decapods' stock enhancement, aquaculture, and temporary no-take zones.

Influence of environmental variables over multiple spatial scales on the population structure of a key marine invertebrate.

Quantifying scale-dependent patterns and linking ecological to environmental variation is required to understand mechanisms regulating biodiversity. We conducted a large-scale survey in rocky shores along the SE Brazilian coast to examine spatial variability in body size and density of an intertidal barnacle (Chthamalus bisinuatus) and its relationships with benthic and oceanographic predictors. Both the size and density of barnacles showed most variation at the smallest spatial scales. On average, barnacle body size was larger on shores located in areas characterised by higher chlorophyll levels, colder waters, low wave action and low influence of freshwater. Barnacles were more abundant at wave-exposed shores. We identified critical scales of spatial variation of an important species and linked population patterns to essential environmental predictors. Our results show that populations of this barnacle are coupled to scale-dependent oceanographic variation. This study offers insights into the mechanisms regulating coastal populations along a little studied coastline.

Physiological basis of interactive responses to temperature and salinity in coastal marine invertebrate: Implications for responses to warming.

Developing physiological mechanistic models to predict species' responses to climate-driven environmental variables remains a key endeavor in ecology. Such approaches are challenging, because they require linking physiological processes with fitness and contraction or expansion in species' distributions. We explore those links for coastal marine species, occurring in regions of freshwater influence (ROFIs) and exposed to changes in temperature and salinity. First, we evaluated the effect of temperature on hemolymph osmolality and on the expression of genes relevant for osmoregulation in larvae of the shore crab Carcinus maenas. We then discuss and develop a hypothetical model linking osmoregulation, fitness, and species expansion/contraction toward or away from ROFIs. In C. maenas, high temperature led to a threefold increase in the capacity to osmoregulate in the first and last larval stages (i.e., those more likely to experience low salinities). This result matched the known pattern of survival for larval stages where the negative effect of low salinity on survival is mitigated at high temperatures (abbreviated as TMLS). Because gene expression levels did not change at low salinity nor at high temperatures, we hypothesize that the increase in osmoregulatory capacity (OC) at high temperature should involve post-translational processes. Further analysis of data suggested that TMLS occurs in C. maenas larvae due to the combination of increased osmoregulation (a physiological mechanism) and a reduced developmental period (a phenological mechanisms) when exposed to high temperatures. Based on information from the literature, we propose a model for C. maenas and other coastal species showing the contribution of osmoregulation and phenological mechanisms toward changes in range distribution under coastal warming. In species where the OC increases with temperature (e.g., C. maenas larvae), osmoregulation should contribute toward expansion if temperature increases; by contrast in those species where osmoregulation is weaker at high temperature, the contribution should be toward range contraction.

Patients' and family members' perspectives on arrhythmias and sudden death in dialysis: the HeartLink focus groups pilot study.

BACKGROUND: Patients receiving dialysis face a high risk of cardiovascular disease, arrhythmia and sudden cardiac death. Few patients, however, are aware of this risk. Implantable cardiac monitors are currently available for clinical use and can continuously monitor cardiac rhythms without the need for transvenous leads. Our goal was to gauge patients' and family members' perceptions of these risks and to identify their concerns about cardiac monitors. METHODS: Two 90-minute focus groups were conducted: one with patients receiving in-center hemodialysis and one with their family members. Trained moderators assessed: (1) knowledge of cardiovascular disease; (2) cardiovascular disease risk in dialysis; (3) risk of death due to cardiovascular disease; (4) best ways to convey this risk to patients/families; and (5) concerns about cardiac monitors. The sessions were audiotaped, transcribed, and independently analyzed by two reviewers to identify core themes. Emblematic quotations were chosen to illustrate the final themes. RESULTS: Nine adult patients and three family members participated. Patients felt education was inadequate and had little knowledge of arrhythmias. Patients'/families' concerns regarding cardiac monitors were related to adverse effects, the notification process, and cosmetic effects. Patients/families felt that nephrologists, not dialysis staff, would be the best source for education. CONCLUSIONS: The preliminary data from this small study population suggest that patients/families are not well aware of the high risk of arrhythmia and sudden cardiac death in dialysis. Further investigation is required to gauge this awareness among patients/families and to assess their impressions of implantable cardiac monitors for arrhythmia detection and management.