Vicuña antipredator diel movement drives spatial nutrient subsidies in a high Andean ecosystem.

Large animals could be important drivers of spatial nutrient subsidies when they ingest resources in some habitats and release them in others, even moving nutrients against elevational gradients. In high Andean deserts, vicuñas (Vicugna vicugna) move daily between nutrient-rich wet meadows, where there is abundant water and forage but high risk of predation by pumas (Puma concolor), and nutrient-poor open plains with lower risk of predation. In all habitats, vicuñas defecate and urinate in communal latrines. We investigated how these latrines impacted soil and plant nutrient concentrations across three habitats in the Andean ecosystem (meadows, plains, and canyons) and used stable isotope analysis to explore the source of fecal nutrients in latrines. Latrine soils had higher concentrations of nitrogen, carbon, and other nutrients than did nonlatrine soils across all habitats. These inputs corresponded with an increase in plant quality (lower C:N) at latrine sites in plains and canyons, but not in meadows. Stable isotope mixing models suggest that ~7% of nutrients in plains latrines originated from vegetation in meadows, which is disproportionately higher than the relative proportion of meadow habitat (2.6%) in the study area. In contrast, ~68% of nutrients in meadow latrines appear to originate from plains and canyon vegetation, though these habitats made up nearly 98% of the study area. Vicuña diel movements thus appear to concentrate nutrients in latrines within habitats and to drive cross-habitat nutrient subsidies, with disproportionate transport from low-lying, nutrient-rich meadows to more elevated, nutrient-poor plains. When these results are scaled up to the landscape scale, the amount of nitrogen and phosphorus subsidized in soil at plains latrines was of the same order of magnitude as estimates of annual atmospheric nitrogen and phosphorus deposition for this region (albeit far more localized and patchy). Thus, vicuña-mediated nutrient redistribution and deposition appears to be an important process impacting ecosystem functioning in arid Andean environments, on par with other major inputs of nutrients to the system.

Effects of Short-Distance Recreational Mushing on Oxytocin, Gastrin, and Creatinine Kinase in Sled Dogs.

A considerable increase in creatinine kinase (CK) activity and gastrin hormone due to exercise has been observed in sled dogs during endurance mushing races; however, there have been no studies on sled dogs during recreational mushing. Although oxytocin hormone is involved in social behaviors and empathy, it has not been studied in sled dogs. This study aimed to assess changes in plasma CK activity, and gastrin and oxytocin concentrations in adult sled dogs used in touristic mushing in North Patagonia, Argentina. Blood samples were collected before, during, and after the winter season of 2017. Creatinine kinase activity measurement was done using an enzymatic assay. Hormone analyses were performed using commercial Enzyme-Linked InmunoSorbent Assay kits. Results showed an expected two-fold increase in CK activity during the winter, with recovering basal values after winter (< 400 UI/L), low and stable levels of gastrin (9.4 ± 8.8 pg/mL), and a slight increase in oxytocin (23%) after mushing activities. No evidence indicated gastrin alterations or muscular damage from touristic mushing, but an oxytocin increase would indicate a stimulation of the brain reward system.

Metabolic fingerprint of insulin resistance in human polymorphonuclear leucocytes.

The present study was aimed at determining the metabolic profile of PMNs in obese subjects, and to explore its potential relationship with insulin resistance (IR). To achieve this goal, a pilot clinical study was performed using PMNs from 17 patients with obesity and IR, and 17 lean controls without IR, which was validated in an additional smaller cohort (consisting of 10 patients and 10 controls). PMNs were isolated from peripheral blood and nuclear magnetic resonance was used to perform the metabolomic analysis. A total of 48 metabolites were quantified. The main metabolic change found in PMNs was a significant increase in 2-aminoisobutyric acid with a direct correlation with HOMA-IR (p<0.001), BMI (p<0.000001) and waist circumference (p<0.000001). By contrast, a decrease of 3-hydroxyisovalerate was observed with an inverse correlation with HOMA-IR (p = 0.001), BMI (p = 0.001) and waist circumference (p = 0.0001). Notably, the metabolic profile in plasma was different than that obtained in PMNs. In summary, our results suggest that the change in 3-hydroxyisovalerate and 2-aminoisobutyric is the key metabolic fingerprint in PMNs of obese subjects with IR. In addition, our methodology could be an easy and reliable tool for monitoring the effect of treatments in the setting of precision medicine.

Perceval Less Invasive Aortic Replacement Register: multicentric Spanish experience with the Perceval S bioprosthesis in moderate-high-risk aortic surgery.

OBJECTIVES: The development of new percutaneous and surgical techniques has reduced the risk associated with aortic valve replacement procedures. We present the results of a Spanish register after initiating a programme for sutureless prostheses in moderate-high-risk patients. METHODS: This prospective multicentre study was carried out from November 2013 to November 2016. Data were obtained from 448 patients in whom a Perceval S prosthesis was implanted. RESULTS: The mean age was 79.24 (standard deviation [SD] 4.1) years, and 61.2% were women. The estimated EuroSCORE I log risk was 11.15% (SD 7.6), with an observed mortality of 4.4% (20 patients). Isolated aortic valve replacement was performed on 69.26% of patients, with 64% involving ministernotomy. The incidence of neurological events was 2%, with 2 permanent cerebrovascular accidents, and 41 (9.2%) patients were implanted with a permanent endocavitary pacemaker. At discharge, 12 (2.6%) patients presented minimal periprosthetic leakage, and 4 (0.89%) patients had moderate leakage. There were 3 reinterventions during follow-up (2 endocarditis and 1 dysfunction due to periprosthetic leak progression). The mean gradient at discharge, 6 months and 1 year was 12.94 (SD 5.3) mmHg, 12.19 (SD 4.7) mmHg and 11.77 (SD 4.7) mmHg, respectively; 59.4% of the patients were octogenarians, with a survival rate of 98% at both 6 months and 1 year at discharge. There was neither valve migration nor early structural degeneration. The mean follow-up was 12 ± 3 months. The 6-month and 1-year mortality was 1.4% and 2.1%, respectively. CONCLUSIONS: This is a prospective multicentric study on the largest cohort of patients with sutureless valves conducted in Spain to date. It is a reproducible procedure that has enabled surgery on patients with a moderate-high risk with low morbidity and mortality, providing good haemodynamic results.

Prognostic factors of infective endocarditis in patients on hemodialysis: A case series from a National Multicenter Registry.

BACKGROUND: Infective endocarditis (IE) is a severe complication associated with high mortality. OBJECTIVES: To examine the clinical characteristics of IE in hemodialysis (HD) patients and to determine prognostic factors related to HD. METHODS: From January 2008 to April 2015, 2488 consecutive patients with definite IE were included. Clinical characteristics of IE patients on HD were compared with those of IE patients who were not on HD. RESULTS: A total of 126 patients (63% male, median age: 66years; IQR: 54-74years) with IE (5.1%) were on HD. Fifty-two patients died during hospitalization (41%) and 17 additional patients (14%) died during the first year. The rate of patients who underwent surgery during hospitalization was lower in HD patients (38 patients, 30%) than in non-HD patients (1177 patients, 50%; p<0.001). Age >70years (OR: 4.1, 95% CI: 1.7-10), heart failure (OR: 3.3, 95% CI: 1.4-7-6), central nervous system (CNS) vascular events (OR: 6.7, 95% CI: 2.1-22) and septic shock (OR: 4.1, 95% CI: 1.4-12.1) were independently associated with fatal outcome in HD patients. Of the 38 patients who underwent surgery, 15 (39.5%) died during hospitalization. CONCLUSIONS: HD patients with IE present a high mortality. Advanced age and complications, such as heart failure, CNS stroke or septic shock, are associated with mortality.

Spatial and seasonal dynamic of abundance and distribution of guanaco and livestock: insights from using density surface and null models.

Monitoring species abundance and distribution is a prerequisite when assessing species status and population viability, a difficult task to achieve for large herbivores at ecologically meaningful scales. Co-occurrence patterns can be used to infer mechanisms of community organization (such as biotic interactions), although it has been traditionally applied to binary presence/absence data. Here, we combine density surface and null models of abundance data as a novel approach to analyze the spatial and seasonal dynamics of abundance and distribution of guanacos (Lama guanicoe) and domestic herbivores in northern Patagonia, in order to visually and analytically compare the dispersion and co-occurrence pattern of ungulates. We found a marked seasonal pattern in abundance and spatial distribution of L. guanicoe. The guanaco population reached its maximum annual size and spatial dispersion in spring-summer, decreasing up to 6.5 times in size and occupying few sites of the study area in fall-winter. These results are evidence of the seasonal migration process of guanaco populations, an increasingly rare event for terrestrial mammals worldwide. The maximum number of guanacos estimated for spring (25,951) is higher than the total population size (10,000) 20 years ago, probably due to both counting methodology and population growth. Livestock were mostly distributed near human settlements, as expected by the sedentary management practiced by local people. Herbivore distribution was non-random; i.e., guanaco and livestock abundances co-varied negatively in all seasons, more than expected by chance. Segregation degree of guanaco and small-livestock (goats and sheep) was comparatively stronger than that of guanaco and large-livestock, suggesting a competition mechanism between ecologically similar herbivores, although various environmental factors could also contribute to habitat segregation. The new and compelling combination of methods used here is highly useful for researchers who conduct counts of animals to simultaneously estimate population sizes, distributions, assess temporal trends and characterize multi-species spatial interactions.

Do cortisol and corticosterone play the same role in coping with stressors? Measuring glucocorticoid serum in free-ranging guanacos (Lama guanicoe).

Habitat can constrain and shape successful ecological and physiological strategies, thus providing the context for the evolution of life-history traits. However, unpredictable challenges, such as storms, natural disasters, and human activities can also have great effects on stress. Glucocorticoids (GCs) are adrenal steroid hormones that play an important role in how vertebrates cope with these predictable and unpredictable environmental challenges. Although assessing GCs levels can have many applications in the study of wildlife and/or captive animals, with or without capturing individuals, it requires a species-specific complete validation (analytical and biological) before its use. In this work, our aim was to: (a) validate a radioimmunoassay (RIA) for measuring GCs levels in L. guanicoe serum; (b) assess cortisol and corticosterone levels (if present) in serum of wild L. guanicoe individuals; and (c) compare the response to acute stressors (handling, shearing, and release). Our results successfully: (a) validated RIA for asses GCs levels in wild ungulates; (b) confirmed the presence for cortisol and corticosterone and showed that both GCs are differently affected by environmental stimuli in L. guanicoe; and (c) showed that GCs exhibit different patterns in the field and in response to acute stressors, making these camelids an interesting endocrinological model when seeking the adaptive functions of a given variation and further emphasizing the complexity of GC physiology in wild mammals.

Cooperative vigilance: the guanaco's (Lama guanicoe) key antipredator mechanism.

The concept of sociality has been associated with the effectiveness of antipredator mechanisms, like cooperative vigilance and the dilution effect. Lama guanicoe (guanaco) is a social native herbivore in South America and a social species. The objectives of this study were to evaluate the antipredator responses of different-sized groups of guanacos in areas with varying predation risks and to determine antipredator mechanisms in guanacos. For this, we measured different antipredator responses to a potential predator (human subjects). Detection of predator and flight distances from predator both increased with a greater number of guanacos per group and with greater distances among guanacos within the social group. Both buffer distance and flight time decreased with a greater number of guanacos per group, but increased with greater distances among guanacos inside the social group. Solitary adult males moved shorter distance and mixed groups moved greater distances. Flight distances were greater in areas with tall and dense vegetation than in areas with low vegetation. Buffer distance and flight time were shorter in undulating land than on flat lands, and groups were usually observed on hill slopes. Our results suggest that the benefit of social grouping in guanacos is the increased probability of avoiding predator with cooperative vigilance and not with the dilution effect. This means that a predator could be detected earlier when approaching a guanaco group than when approaching a solitary individuals and could thus be avoided.

FM19G11: A new modulator of HIF that links mTOR activation with the DNA damage checkpoint pathways.

The network consisting of mTOR and p53 pathways is crucial to understanding a wide variety of physiological and pathological events, including cancer and aging. In addition, the HIF1alpha protein, a downstream target of mTOR, is a hallmark of different tumor types and was the desired strategy of many drug discovery efforts. Here we present the novel chemical entity FM19G11, a new modulator of HIF1alpha expression, which was used as a molecular tool to dissect and further characterize the cross-talk between these signaling cascades in human colon carcinoma cell lines. To our knowledge, FM19G11 is the first drug that triggers a DNA damage response (DDR) associated with G(1)/S-phase arrest in a p53-dependent manner, due to rapid hyper-activation of the growth signaling pathway through mTOR. Assessment of colonies demonstrated that FM19G11 decreases the clonogenicity of HT29, HCT116/p53(+/+) and HCT116/p53(-/-) cells. Moreover, FM19G11 causes significant lower colony growth in soft agar of p53-proficient human colon cancer cells. Consequently, p53 sensitizes human colon cancer cells to FM19G11 by significant reduction of their viability, lessening their colony formation capability and shrinking their anchorage-independent growth. Cell signaling studies served to assign a new mode of action to FM19G11, whose tumor-suppressant activity compromises the survival of functional p53 malignant cells.