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Understanding the adaptive basis of life history variation is a central goal in evolutionary ecology. The use of model species enables the combination of molecular mechanistic knowledge with ecological and evolutionary questions, but the study of life history variation in natural environments is required to merge these disciplines. Here, we tested for clinal variation in life history and associated traits along an environmental and altitudinal gradient in the model species Arabidopsis thaliana. Seventeen natural populations of A. thaliana were geo-referenced in northeastern Spain on a gradient in which precipitation increases but maximum spring temperature and minimum winter temperature decrease with altitude. One hundred and eighty-nine genotypes from the 17 populations were grown under uniform controlled conditions. Variations in traits related to biomass allocation, fecundity, phenology and vegetative growth were tested for relationships with the altitude and climatic variables associated with the home sites. Aboveground mass, number of rosette leaves at bolting, developmental time and seed weight increased with the home site's altitude. Root allocation, vegetative growth during winter and number of seeds decreased with altitude. We suggest that the differences among home sites provide clues to the variation in adaptive strategies associated with the climatic gradient. We compared these results with adaptations and clinal relationships reported for other species and with molecular mechanisms described in Arabidopsis. [ABSTRACT FROM AUTHOR]

Bryophytes have increased in abundance in northern regions, and climate changes have been proposed to account for this change. However, changes in the population dynamics of microtine rodents may also contribute to changes in bryophyte abundance. New evidence indicates a tendency for microtine rodent population oscillations to change from periodicity of 3-5 years to become irregular or acyclic. The impact on ecosystem functioning is potentially great. We study the impact of variation in microtine rodent population characteristics, such as cycle length and amplitude, on the population dynamics of the boreal, clonal moss Hylocolmium splendens. We use experimental and observational demographic data to construct 127 scenarios representing all combinations of disturbance type (gap formation and/or clipping), period (cyclic with 4, 6, 12, or 24 years between rodent peaks; or acyclic with constant or stochastically varying annual disturbance severity) and disturbance severity (fraction of individuals affected by disturbance in each year relative to the maximum disturbance carried out in the field experiment; seven levels). Population data collected in the field during 13 years were used as a baseline scenario. By subjecting all scenarios to stochastic matrix modeling, we demonstrate considerable impact of microtine rodent on the population dynamics of H. splendens, most notably when rodent populations fluctuate with short periods and high peak disturbance seventies. Under the same average disturbance severity, H. splendens population growth rates are highest in acyclic scenarios and are progressively reduced with increasing peak disturbance seventies (i.e., with increasing period). Stochastic elasticity analyses show that in less variable environments mature segment survival contributes more to the population growth rate, while in more variable environments the regeneration pathway (branching of older parts of the plant) plays a stronger role, inevitably leading to lower population fitness. Our results support the hypothesis that breakdown of cyclic rodent population dynamics accentuates increase in the abundance of H. splendens and other large bryophytes in boreal forests in Norway, observed empirically in recent years and primarily ascribed to climatic change. [ABSTRACT FROM AUTHOR]

Ecological factors contributing to fecundity showed a high degree of between-year variability. Pre-dispersal fruit predation had a minor influence on total reproductive output, and most of the variability was found among individuals within populations and years. Spatio-temporal variability in growth and survival was rather low but significant, whereas recruitment showed important between-population variability. Among-year variability in fecundity and growth was related to climatic fluctuations on a regional scale, notably rainfall and temperature in a particular period, while the spatial variability in survival and recruitment was explained by within-population (patch) habitat quality. Although R. myconi is able to withstand repeated periods of drought, water availability seems to be the most important factor affecting plant performance in all the study populations. These findings suggest that the long-term persistence of species showing remnant population dynamics in habitats under the influence of Mediterranean climate might be threatened by increased aridity as a result of climate change. [ABSTRACT FROM AUTHOR]

Peripheral neuropathy is a rare, yet treatable manifestation of sarcoidosis, a multisystem disorder characterized by the presence of non-caseating granulomas that are seldom found in nerve biopsy specimens. In order to learn more about the subject, we reviewed our clinical and pathological findings in a series of 11 patients (six men and five women aged 26-83 years) with symptomatic neuropathy associated with characteristic granulomas in nerve biopsy specimens. Only two patients were known to have sarcoidosis before the occurrence of the neuropathy. The neuropathy was focal or multifocal in six patients, including one with a multifocal neuropathy associated with conduction blocks, and one with a multifocal axonal motor deficit. Four patients had a distal symmetrical deficit and one patient had a Guillain-Barré-like syndrome with facial diplegia and respiratory failure. Serum angiotensin-converting enzyme concentration was elevated in only two patients. Epineurial granulomas and perineuritis were present in all nerve specimens. The inflammatory infiltrates invaded the endoneurium, following connective tissue septae and blood vessels, in five patients. Multinucleated giant cells were found in eight patients and necrotizing vasculitis in seven. Inflammatory lesions were associated with variable, asymmetrical involvement of nerve fascicles and axon loss. A muscle specimen was sampled during the same procedure in 10 patients. It showed inflammatory infiltrates and granulomas in nine patients and necrotizing vasculitis in two. Immunolabeling showed a mixed inflammatory infiltrate of T cells (predominantly CD4+ cells) and macrophages, in keeping with a delayed hypersensitivity reaction. In addition to nerve involvement, all patients had at least one other tissue or organ affected, including muscle in nine patients, lungs and/or intrathoracic lymph nodes in eight, skin in three, arthritis in two, and peripheral lymph nodes, stomach and eye in one patient each.... [ABSTRACT FROM AUTHOR]

Background and Aims: Complex aortic atheroma (CAA) is a common cause of acute brain ischemia (BI), including ischemic stroke (IS) and transient ischemic attack (TIA), and is associated with recurrence. The CHA2DS2-VASc score is a useful tool for predicting stroke in patients with atrial fibrillation (AF), and can also predict cardiovascular events in other populations, including non-AF populations. The ADAM-C score is a new risk score for predicting the diagnostic yield of transesophageal echocardiography (TEE) after BI. We aimed to evaluate the ability of CHA2DS2-VASc and ADAM-C scores to predict CAA after BI., Methods: This prospective, multicenter, observational study included 1479 patients aged over 18 years who were hospitalized for BI. CAA was defined as the presence of one or more of the following criteria: thrombus, ulcerated plaque, or plaque thickening ≥ 4 mm., Results: CAA was diagnosed in 216 patients (14.6%). CHA2DS2-VASc and ADAM-C scores were significantly higher in the CAA group versus the non-CAA group (P < .0001 for both). The CHA2DS2-VASc and ADAM-C scores appear to be good predictors of CAA (AUC 0.699 [0.635, 0.761] and 0.759 [0.702, 0.814], respectively). The sensitivity, specificity, predictive positive value (PPV), and negative predictive value (NPV) of the scores for detecting CAA were 94%, 22%, 17%, and 96%, respectively, for a CHA2DS2-VASc score < 2, and 90%, 46%, 22%, and 96%, respectively, for an ADAM-C score < 3 CONCLUSIONS: CHA2DS2-VASc and ADAM-C scores are able to predict CAA after BI. CHA2DS2-VASc < 2 and ADAM-C < 3 both have an interesting NPV of 96%., (© 2021 Wiley Periodicals LLC.)

Background Long-working hours (LWH) are a probable risk factor for ischemic heart diseases (IHD); however, no previous study has considered duration of exposure to LWH when addressing this topic. We aimed to determine the association between cumulative exposure to LWH and IHD while accounting for relevant confounders. Methods and Results In this retrospective study, we included all baseline participants from the French population-based cohort CONSTANCES. Part-time employees and those who reported a cardiac event in the 5 years before LWH exposure were excluded. From self-administered questionnaires and clinical examinations, we obtained participants' age, sex, body mass index, occupational status, smoking habits, high blood pressure, diabetes mellitus, familial history of cardiovascular disease, dyslipidemia, exposure to LWH, and its duration. We defined LWH as working for >10 hours daily for at least 50 days per year. The main outcome was reported history of IHD, ie, myocardial infarction or angina pectoris, during a clinical examination. Of 137 854 included participants, 69 774 were men. There were 1875 cases (1.36%) of IHD, and exposure to LWH was reported by 42 462 subjects (30.8%) among whom 14 474 (10.50%) reported exposure for at least 10 years. Overall, exposure to LWH for ≥10 years was associated with an increased risk of IHD, adjusted odds ratio (aOR) 1.24 (1.08-1.43), P =0.0021. In stratified analyses, this effect was not observed in women, but was significant amongst men, aOR 1.28 (1.11-1.48), P =0.0008. Conclusions This large population-based study supports an association between cumulative exposure to LWH and IHD in men. Future research should consider relevant strategies for reducing LWH exposure and duration.

Background and Aim: The clinical utility of transesophageal echocardiography (TEE) after brain ischemia (BI) remains a matter of debate. We aimed to evaluate the clinical impact of TEE and to build a score that could help physicians to identify which patients should better benefit from TEE., Methods: This prospective, multicenter, observational study included patients over 18 years old, hospitalized for BI. TEE findings were judged discriminant if the results showed important information leading to major changes in the management of patients. Most patients with patent foramen ovale were excluded. Variables independently associated with a discriminant TEE were used to build the prediction model., Results: Of the entire population (1479 patients), 255 patients (17%) were classified in the discriminant TEE group. Five parameters were selected as predictors of a discriminant TEE. Accordingly, the ADAM-C score could be calculated as follows: Score = 4 (if age ≥60) + 2 (if diabetes) + 2 (if aortic stenosis from any degrees) + 1 (if multi-territory stroke) + 2 (if history of coronary artery disease). At a threshold lower than 3, the sensitivity, specificity, positive predictive value, and negative predictive value (NPV) of detecting discriminant TEE were 88% (95% CI 85-90), 44% (95% CI 41-47), 21% (95% CI 19-27), and 95% (95% CI 94-97), respectively., Conclusion: A simple score based on clinical and transthoracic echocardiographic parameters can help physicians to identify patients who might not benefit from TEE. Indeed, a score lower than 3 has an interesting NPV of 95% (95% CI 94-97)., (© 2018 Wiley Periodicals, Inc.)