Exercise associated factors affecting cardiovascular health and function: from myocyte signaling to genetic variations

The exact mechanisms of the exercise induced adaptations is not lucid, but recent studies have delineated two means of signaling by which the adaptations occur (1) substrate availability signaling (metabolic stress) (2) hormone-receptor signaling. We have decided to specifically investigate two metabolic signaling enzymes [AMP-activated kinase (AMPK) and Sirtuin 1(SIRT1)] and two hormones [Adiponectin and Adrenergic stimulation].Tis based on four papers with the following conclusions: (1)Increase in SIRT1 activity and expression in H9c2 cells treated with phenylephrine is an adaptive response to the hypertrophic stress, mediated by AMPK. (2)The lack of optimal nutritional conditions (energetic substrates) due to a prolonged activation of AMPK can contrast the establishment of hypertrophy, possibly also by means of the negative modulation of ODC activity. (3) Our findings offer a possibile hypothesis as to the fact the the G allele on site 45 could lead to the increasd risk of Type II diabetes through a decrease in lean body mass. (4) Our results suggest that there is an ADIPOQ gene effect in relation to bone parameters. Statistical analysis show that the presence of the T allele in position 45 favors an increase in lumbar spine bone mineral content (BMC) when compared to subjects with a G allele substitution, which can be do the the increase in lean body mass in this genotype group.

Approaching water stress in the Alps: Transdisciplinary co-production of systems, target and transformation knowledge

There is increasing recognition that transdisciplinary approaches are needed to create suitable knowledge for sustainable water management. However, there is no common understanding of what transdisciplinary research may be and there is very limited debate on potentials and challenges regarding its implementation. Against this background, this paper presents a conceptual framework for transdisciplinary co-production of knowledge in water management projects oriented towards more sustainable use of water. Moreover, first experiences with its implementation are discussed. In so doing, the focus lies on potentials and challenges related to the co-production of systems, target and transformation knowledge by researchers and local stakeholders.

Exercise induces rapid interstitial lung water accumulation in patients with chronic mountain sickness

Chronic mountain sickness (CMS) is a major public health problem in mountainous regions of the world. In its more advanced stages, exercise intolerance is often found, but the underlying mechanism is not known. Recent evidence indicates that exercise-induced pulmonary hypertension is markedly exaggerated in CMS. We speculated that this problem may cause pulmonary fluid accumulation and aggravate hypoxemia during exercise.

RV contractility and exercise-induced pulmonary hypertension in chronic mountain sickness: a stress echocardiographic and tissue Doppler imaging study

OBJECTIVES The aim of this study was to evaluate right ventricular (RV) and left ventricular function and pulmonary circulation in chronic mountain sickness (CMS) patients with rest and stress echocardiography compared with healthy high-altitude (HA) dwellers. BACKGROUND CMS or Monge's disease is defined by excessive erythrocytosis (hemoglobin >21 g/dl in males, 19 g/dl in females) and severe hypoxemia. In some cases, a moderate or severe increase in pulmonary��pressure is present, suggesting a similar pathogenesis of pulmonary hypertension. METHODS In La Paz (Bolivia, 3,600 m sea level), 46 CMS patients and 40 HA dwellers of similar age were evaluated at rest and during semisupine bicycle exercise. Pulmonary artery pressure (PAP), pulmonary vascular resistance, and cardiac function were estimated by Doppler echocardiography. RESULTS Compared with HA dwellers, CMS patients showed RV dilation at rest (RV mid diameter: 36������5 mm��vs. 32 �� 4 mm, CMS vs. HA, p��= 0.001) and reduced RV fractional area change both at rest (35���� 9% vs. 43������9%, p��= 0.002) and during exercise (36 �� 9% vs. 43 �� 8%, CMS vs. HA, p��= 0.005). The RV systolic longitudinal function (RV-S') decreased in CMS patients, whereas it increased in the control patients (p��<��0.0001) at peak stress. The RV end-systolic pressure-area relationship, a load independent surrogate of RV contractility, was similar in CMS patients and HA dwellers with a significant increase in systolic PAP and pulmonary vascular resistance in CMS patients (systolic PAP: 50 �� 12 mm Hg vs. 38 �� 8 mm Hg, CMS vs. HA, p < 0.0001; pulmonary vascular resistance: 2.9 �� 1 mm Hg/min/l vs.��2.2 �� 1 mm Hg/min/l, p��= 0.03). Both groups showed comparable systolic and diastolic left ventricular function both at rest and during stress. CONCLUSIONS Comparable RV contractile reserve in CMS and HA suggests that the lower resting values of RV function in CMS may represent a physiological adaptation to chronic hypoxic conditions rather than impaired RV function. (Chronic Mountain Sickness, Systemic Vascular Function [CMS]; NCT01182792).

Impacts of drought stress on water relations and carbon assimilation in grassland species at different altitudes

Grassland is an important ecosystem type which is not only used agriculturally, but also covers sites which cannot be used for other purposes, e.g. in very steep locations or above timberlines. Prolonged summer droughts in the mid-term future, as are predicted for Central Europe, are expected to have a major impact on such ecosystems. To address this topic, rainfall exclusion via shelters was performed on three grassland sites at different altitudes (393, 982 and 1978 m above sea level) in Switzerland. Diurnal drought treatment effects were studied at each study site on a completely sunny day towards the end of an 8���10 week shelter period. Ecophysiological parameters including gas exchange (An, gs and intrinsic WUE) and chlorophyll a fluorescence (Fv/Fm, ��PSII and NPQ) were considered for several species. The lowland and the Alpine field site were more strongly affected by soil drought than the pre-Alpine site. At all sites, grasses showed different patterns of reductions in stomatal conductance under soil drought compared to legumes and forbs. In addition, grasses were significantly more affected by reductions in assimilation rates at all sites. Time courses of reductions in assimilation rates relative to controls differed between species at the Alpine site, as some species showed reduced assimilation rates at this site in the early morning. Thus, similar rainfall exclusion treatments can trigger different reactions in various species at different sites, which might not become obvious during mere midday measurements. Overall, results suggest strong impacts of prolonged summer drought on grassland net photosynthesis especially at the Alpine site and, within sites, for grasses

Dehydrin expression as a potential diagnostic tool for cold stress in white clover

Cold acclimation is important for crop survival in environments undergoing seasonal low temperatures. It involves the induction of defensive mechanisms including the accumulation of different cryoprotective molecules among which are dehydrins (DHN). Recently several sequences coding for dehydrins were identified in white clover (Trifolium repens). This work aimed to select the most responsive to cold stress DHN analogues in search for cold stress diagnostic markers. The assessment of dehydrin transcript accumulation via RT-PCR and immunodetection performed with three antibodies against the conserved K-, Y-, and S-segment allowed to outline different dehydrin types presented in the tested samples. Both analyses confirmed that YnKn dehydrins were underrepresented in the controls but exposure to low temperature specifically induced their accumulation. Strong immunosignals corresponding to 37���40 kDa with antibodies against Y- and K-segment were revealed in cold-stressed leaves. Another ���cold-specific��� band at position 52���55 kDa was documented on membranes probed with antibodies against K-segment. Real time RT-qPCR confirmed that low temperatures induced the accumulation of SKn and YnSKn transcripts in leaves and reduced their expression in roots. Results suggest that a YnKn dehydrin transcript with GenBank ID: KC247805 and the immunosignal at 37���40 kDa, obtained with antibodies against Y- and K-segment are reliable markers for cold stress in white clover. The assessment of SKn (GenBank ID: EU846208) and YnSKn (GenBank ID: KC247804) transcript levels in leaves could serve as additional diagnostic tools.

The role of abscisic acid and water stress in root herbivore-induced leaf resistance

Herbivore-induced systemic resistance occurs in many plants and is commonly assumed to be adaptive. The mechanisms triggered by leaf-herbivores that lead to systemic resistance are largely understood, but it remains unknown how and why root herbivory also increases resistance in leaves. To resolve this, we investigated the mechanism by which the root herbivore Diabrotica virgifera induces resistance against lepidopteran herbivores in the leaves of Zea mays. Diabrotica virgifera infested plants suffered less aboveground herbivory in the field and showed reduced growth of Spodoptera littoralis caterpillars in the laboratory. Root herbivory did not lead to a jasmonate-dependent response in the leaves, but specifically triggered water loss and abscisic acid (ABA) accumulation. The induction of ABA by itself was partly responsible for the induction of leaf defenses, but not for the resistance against S. littoralis. Root-herbivore induced hydraulic changes in the leaves, however, were crucial for the increase in insect resistance. We conclude that the induced leaf resistance after root feeding is the result of hydraulic changes, which reduce the quality of the leaves for chewing herbivores. This finding calls into question whether root-herbivore induced leaf-resistance is an evolved response. �� The Authors (2010). Journal compilation �� New Phytologist Trust (2010).

Modeling tree water deficit from microclimate: an approach to quantifying drought stress

Tree water deficit estimated by measuring water-related changes in stem radius (DeltaW) was compared with tree water deficit estimated from the output of a simple, physiologically reasonable model (DeltaW(E)), with soil water potential (Psi(soil)) and atmospheric vapor pressure deficit (VPD) as inputs. Values of DeltaW were determined by monitoring stem radius changes with dendrometers and detrending the results for growth, We followed changes in DeltaW and DeltaW(E) in Pinus sylvestris L. and Quercus pubescens Willd. over 2 years at a dry site (2001-2002; Salgesch, Wallis) and in Picea abies (L.) Karst. for 1 year at a wet site (1998; Davos, Graubuenden) in the Swiss Alps. The seasonal courses of DeltaW in deciduous species and in conifers at the same site were similar and could be largely explained by variation in DeltaW(E). This finding strongly suggests that DeltaW, despite the known species-specific differences in stomatal response to microclimate, is mainly explained by a combination of atmospheric and soil conditions. Consequently, we concluded that trees are unable to maintain any particular DeltaW. Either Psi(soil) or VPD alone provided poorer estimates of AWthan a model incorporating both factors. As a first approximation of DeltaW(E), Psi(soil) can be weighted so that the negative mean Psi(soil) reaches 65 to 75% of the positive mean daytime VPD over a season (Q. pubescens: similar to65%, P abies: similar to70%, P sylvestris: similar to75%). The differences in DeltaW among species can be partially explained by a different weighting of Psi(soil) against VPD. The DeltaW of P. sylvestris was more dependent on Psi(soil) than that of Q. pubescens, but less than that of P. abies, and was less dependent on VPD than that of P. abies and Q. pubescens. The model worked well for P. abies at the wet site and for Q. pubescens and P. sylvestris at the dry site, and may be useful for estimating water deficit in other tree species.

The Efficacy of a Novel Microbial 6-Phytase Expressed in Aspergillus oryzae on the Performance and Phosphorus Utilization of Cold- and Warm-Water Fish: Rainbow Trout, Oncorhynchus mykiss , and Nile Tilapia, Oreochromis niloticus

The efficacy and tolerance of a novel microbial 6-phytase were investigated in rainbow trout, Oncorhynchus mykiss, and Nile tilapia, Oreochromis niloticus. Reference diets were sufficient in available phosphorus (P). The test diet limiting in available P was supplemented with phytase at 500, 1000, or 2000 phytase units/kg feed. The enzyme was effective in increasing total P apparent digestibility coefficient in relation to increasing the dose of phytase in rainbow trout and Nile tilapia. Zinc apparent digestibility improved in relation to phytase supplementation in rainbow trout. P release due to phytase supplementation ranged from 0.06 to 0.18% P/kg feed in rainbow trout and from 0.13 to 0.26% P/kg feed in Nile tilapia. A 58-d performance trial was conducted to evaluate tolerance of fish to phytase supplementation. Dietary treatments consisted of a basal diet without phytase or supplemented with 2000 and 200,000 phytase units/kg feed. Results indicate that this novel microbial 6-phytase is well tolerated by fish. Significant improvements for growth as well as feed conversion ratio were observed when the phytase was fed at 2000 phytase units/kg feed. This phytase is proven efficient in releasing P from phytate and could be added when plants are used for fish meal replacement in diets for salmonid and omnivorous fish.

The role of cold stress in predicting extra cardiovascular and respiratory admissions

Although several studies have examined effects of air temperature and/or other meteorological variables separately on disease rates, the relationship of meteorological variables and human disease is, in fact, rather complex in the ���real-world��� [1,2] including the number of potential variables to be considered and their weighting. In other words, 1�����C of air temperature difference in a warm climate may not necessarily mean the same in a cold climate across regions on Earth [3,4]. Why some seasonality was observed in certain regions at certain times only is likely due in part to the imprecise weather estimation from mean, maximum, or minimum air temperature or the definition of study catchments or time period to be included.

Climatic and anthropogenic changes in Western Switzerland: Impacts on water stress

Recent observed hydro-climatic changes in mountainous areas are of concern as they may directly affect capacity to fulfill water needs. The canton of Vaud in Western Switzerland is an example of such a region as it has experienced water shortage episodes during the past decade. Based on an integrated modeling framework, this study explores how hydro-climatic conditions and water needs could evolve in mountain environments and assesses their potential impacts on water stress by the 2060 horizon. Flows were simulated based on a daily semi-distributed hydrological model. Future changes were derived from Swiss climate scenarios based on two regional climate models. Regarding water needs, the authorities of the canton of Vaud provided a population growth scenario while irrigation and livestock trends followed a business-as-usual scenario. Currently, the canton of Vaud experiences moderate water stress from June to August, except in its Alpine area where no stress is noted. In the 2060 horizon, water needs could exceed 80% of the rivers' available resources in low- to mid-altitude environments in mid-summer. This arises from the combination of drier and warmer climate that leads to longer and more severe low flows, and increasing urban (+ 40%) and irrigation (+ 25%) water needs. Highlighting regional differences supports the development of sustainable development pathways to reduce water tensions. Based on a quantitative assessment, this study also calls for broader impact studies including water quality issues.