Is hypoxia training good for muscles and exercise performance?

Altitude training has become very popular among athletes as a means to further increase exercise performance at sea level or to acclimatize to competition at altitude. Several approaches have evolved during the last few decades, with "live high-train low" and "live low-train high" being the most popular. This review focuses on functional, muscular, and practical aspects derived from extensive research on the "live low-train high" approach. According to this, subjects train in hypoxia but remain under normoxia for the rest of the time. It has been reasoned that exercising in hypoxia could increase the training stimulus. Hypoxia training studies published in the past have varied considerably in altitude (2300-5700 m) and training duration (10 days to 8 weeks) and the fitness of the subjects. The evidence from muscle structural, biochemical, and molecular findings point to a specific role of hypoxia in endurance training. However, based on the available performance capacity data such as maximal oxygen uptake (Vo(2)max) and (maximal) power output, hypoxia as a supplement to training is not consistently found to be advantageous for performance at sea level. Stronger evidence exists for benefits of hypoxic training on performance at altitude. "Live low-train high" may thus be considered when altitude acclimatization is not an option. In addition, the complex pattern of gene expression adaptations induced by supplemental training in hypoxia, but not normoxia, suggest that muscle tissue specifically responds to hypoxia. Whether and to what degree these gene expression changes translate into significant changes in protein concentrations that are ultimately responsible for observable structural or functional phenotypes remains open. It is conceivable that the global functional markers such as Vo(2)max and (maximal) power output are too coarse to detect more subtle changes that might still be functionally relevant, at least to high-level athletes.

Block training periodization in alpine skiing: effects of 11-day HIT on VO2max and performance

Attempting to achieve the high diversity of training goals in modern competitive alpine skiing simultaneously can be difficult and may lead to compromised overall adaptation. Therefore, we investigated the effect of block training periodization on maximal oxygen consumption (VO2max) and parameters of exercise performance in elite junior alpine skiers. Six female and 15 male athletes were assigned to high-intensity interval (IT, N = 13) or control training groups (CT, N = 8). IT performed 15 high-intensity aerobic interval (HIT) sessions in 11 days. Sessions were 4 x 4 min at 90-95% of maximal heart rate separated by 3-min recovery periods. CT continued their conventionally mixed training, containing endurance and strength sessions. Before and 7 days after training, subjects performed a ramp incremental test followed by a high-intensity time-to-exhaustion (tlim) test both on a cycle ergometer, a 90-s high-box jump test as well as countermovement (CMJ) and squat jumps (SJ) on a force plate. IT significantly improved relative VO2max by 6.0% (P < 0.01; male +7.5%, female +2.1%), relative peak power output by 5.5% (P < 0.01) and power output at ventilatory threshold 2 by 9.6% (P < 0.01). No changes occurred for these measures in CT. tlim remained unchanged in both groups. High-box jump performance was significantly improved in males of IT only (4.9%, P < 0.05). Jump peak power (CMJ -4.8%, SJ -4.1%; P < 0.01), but not height decreased in IT only. For competitive alpine skiers, block periodization of HIT offers a promising way to efficiently improve VO2max and performance. Compromised explosive jump performance might be associated with persisting muscle fatigue.

A hypoxia complement differentiates the muscle response to endurance exercise

Metabolic stress is believed to constitute an important signal for training-induced adjustments of gene expression and oxidative capacity in skeletal muscle. We hypothesized that the effects of endurance training on expression of muscle-relevant transcripts and ultrastructure would be specifically modified by a hypoxia complement during exercise due to enhanced glycolytic strain. Endurance training of untrained male subjects in conditions of hypoxia increased subsarcolemmal mitochondrial density in the recruited vastus lateralis muscle and power output in hypoxia more than training in normoxia, i.e. 169 versus 91% and 10 versus 6%, respectively, and tended to differentially elevate sarcoplasmic volume density (42 versus 20%, P = 0.07). The hypoxia-specific ultrastructural adjustments with training corresponded to differential regulation of the muscle transcriptome by single and repeated exercise between both oxygenation conditions. Fine-tuning by exercise in hypoxia comprised gene ontologies connected to energy provision by glycolysis and fat metabolism in mitochondria, remodelling of capillaries and the extracellular matrix, and cell cycle regulation, but not fibre structure. In the untrained state, the transcriptome response during the first 24 h of recovery from a single exercise bout correlated positively with changes in arterial oxygen saturation during exercise and negatively with blood lactate. This correspondence was inverted in the trained state. The observations highlight that the expression response of myocellular energy pathways to endurance work is graded with regard to metabolic stress and the training state. The exposed mechanistic relationship implies that the altitude specificity of improvements in aerobic performance with a 'living low-training high' regime has a myocellular basis.

Trauma mechanisms, patterns of injury, and outcomes in a retrospective study of 71 burns from civil gas explosions

Although explosion injuries caused by terror attacks or in war are evaluated in many studies, limited information about civil explosion injuries can be found in the literature.

Percutaneous collagen induction-regeneration in place of cicatrisation?

Ablative procedures that are used for the improvement of a degenerative process that leads to a loss of skin elasticity and integrity, injure or destroy the epidermis and its basement membrane and lead to fibrosis of the papillary dermis. It was recently shown in clinical and laboratory trials that percutaneous collagen induction (PCI) by multiple needle application is a method for safely treating wrinkles and scars and smoothening the skin without the risk of dyspigmentation. In our study, we describe the effect of PCI on epidermal thickness and the induction of genes relevant for regenerative processes in the skin in a small animal model.

Percutaneous collagen induction therapy: an alternative treatment for burn scars

This study aims to evaluate percutaneous collagen induction (PCI) in post-burn scarring.

[A Swiss multicentric project to improve the prevention of cardiovascular event recurrence after acute coronary syndromes]

Recurrence of cardiovascular events and mortality remain high after acute coronary syndromes. A Swiss multicentric study, "Inflammation and acute coronary syndromes (ACS)--Novel strategies for prevention and clinical managements", is currently underway with the support of the Swiss National Science Foundation. The study includes a clinical research subproject of which the aim is to assess the impact of the ELIPS program (multi-dimEnsionaL prevention Program after acute coronary Syndrome) on the recurrence of cardiovascular events after an ACS. The basic research sub-projects aim to investigate novel cardiovascular risk biomarkers and genetic determinants of recurrence and to study the role of stem cells after an ACS. Another sub-project will evaluate intracoronary imaging techniques and the efficacy of different types of stents.

Atorvastatin attenuates hepatic fibrosis in rats after bile duct ligation via decreased turnover of hepatic stellate cells

Activation of hepatic stellate cells (HSC) and transdifferentiation to myofibroblasts following liver injury is the main culprit for hepatic fibrosis. Myofibroblasts show increased proliferation, migration, contraction, and production of extracellular matrix (ECM). In vitro, HMG-CoA reductase inhibitors (statins) inhibit proliferation and induce apoptosis of myofibroblastic HSC. To investigate the antifibrotic effects of atorvastatin in vivo we used bile duct ligated rats (BDL).

MRI-based breast volumetry-evaluation of three different software solutions

As lipofilling of the female breast is becoming more popular in plastic surgery, the use of MRI to assess breast volume has been employed to control postoperative results. Therefore, we sought to evaluate the accuracy of magnetic resonance imaging (MRI)-based breast volumetry software tools by comparing the measurements of silicone implant augmented breasts with the actual implant volume specified by the manufacturer. MRI-based volume analysis was performed in eight bilaterally augmented patients (46 ± 9 years) with three different software programs (Brainlab© I plan 2.6 neuronavigation software; mass analysis, version 5.3, Medis©; and OsiriX© v.3.0.2. 32-bit). The implant volumes analysed by the BrainLab© software had a mean deviation of 2.2 ± 1.7% (r?=?0.99) relative to the implanted prosthesis. OsiriX© software analysis resulted in a mean deviation of 2.8 ± 3.0% (r?=?0.99) and the Medis© software had a mean deviation of 3.1 ± 3.0% (r?=?0.99). Overall, the volumes of all analysed breast implants correlated very well with the real implant volumes. Processing time was 10 min per breast with each system and 30 s (OsiriX©) to 5 min (BrainLab© and Medis©) per silicone implant. MRI-based volumetry is a powerful tool to calculate both native breast and silicone implant volume in situ. All software solutions performed well and the measurements were close to the actual implant sizes. The use of MRI breast volumetry may be helpful in: (1) planning reconstructive and aesthetic surgery of asymmetric breasts, (2) calculating implant size in patients with missing documentation of a previously implanted device and (3) assessing post-operative results objectively.