Micro- and macrovascular function in the highest city in the world: a cross sectional study.

Background: Since vascular responses to hypoxia in both healthy high-altitude natives and chronic mountain sickness (a maladaptive high-altitude pathology characterised by excessive erythrocytosis and the presence of symptoms-CMS) remain unclear, the role of inflammation and oxidative/nitrosative stress on the endothelium- and - responses in both the micro- and macrocirculation, in healthy Andeans at different altitudes and in CMS patients, was examined.

Methods: 94 men were included: 18 lowlanders (LL), 38 healthy highlanders permanently living at 3800 m (n = 21-HL-3800) or in La Rinconada, the highest city in the world (5100-5300 m) (n = 17-HL-5100/No CMS). Moreover, 14 participants with mild (Mild CMS) and 24 with moderate to severe CMS (Mod/Sev CMS) were recruited.

Body composition assessment of people with overweight/obesity with a simplified magnetic resonance imaging method.

To develop a simplified magnetic resonance imaging method (MRI) to assess total adipose tissue (AT) and adipose tissue free mass (ATFM) from three single MRI slices in people with overweight/obesity in order to implement body composition follow-up in a clinical research setting. Body composition of 310 participants (70 women and 240 men, age: 50.8 ± 10.

Nocturnal hypoxemia, blood pressure, vascular status and chronic mountain sickness in the highest city in the world.

Introduction: Chronic mountain sickness (CMS) is a condition characterized by excessive erythrocytosis in response to chronic hypobaric hypoxia. CMS frequently triggers cardiorespiratory diseases such as pulmonary hypertension and right or left heart failure. Ambient hypoxia might be further amplified night-time by intermittent hypoxia related to sleep-disordered breathing (SDB) so that sleep disturbance may be an important feature of CMS.

Toward Neuro-Oncologic Clinical Trials of High-Dose-Rate Synchrotron Microbeam Radiation Therapy: First Treatment of a Spontaneous Canine Brain Tumor.

Purpose: The high potential of microbeam radiation therapy (MRT) in improving tumor control while reducing side effects has been shown by numerous preclinical studies. MRT offers a widened therapeutic window by using the periodical spatial fractionation of synchrotron generated x-rays into an array of intense parallel microbeams. MRT now enters a clinical transfer phase.

Effects of high intensity interval training on sustained reduction in cardiometabolic risk associated with overweight/obesity. A randomized trial.

Background: Considering the potential greater cardiocirculatory effects of high intensity interval training (HIIT), we hypothesized that a 2-month supervised high volume short interval HIIT would induce greater improvements in CRF and cardiometabolic risk and increase long-term maintenance to physical activity compared to isocaloric moderate intensity continuous training (MICT) in overweight/obesity.

Methods: Sixty (19 females) subjects with overweight/obesity were randomized to three training programs (3 times/week for 2 months): MICT (45 min, 50% peak power output-PPO), HIIT (22 × 1-min cycling at 100% PPO/1-min passive recovery) and HIIT-RM (RM: recovery modulation, i.e.

MEDEX 2015: Prophylactic Effects of Positive Expiratory Pressure in Trekkers at Very High Altitude.

Positive expiratory pressure (PEP) breathing has been shown to increase arterial oxygenation during acute hypoxic exposure but the underlying mechanisms and consequences on symptoms during prolonged high-altitude exposure remain to be elucidated. Twenty-four males (41 ± 16 years) were investigated, at sea level and at 5,085 m after 18 days of trekking from 570 m. Participants breathed through a face-mask with PEP = 0 cmHO (PEP, 0-45 min) and with PEP = 10 cmHO (PEP, 46-90 min).

Medex 2015: The key role of cardiac mechanics to maintain biventricular function at high altitude.

New Findings: What is the central question of this study? This study is the first to investigate the effects of high-altitude trekking on biventricular mechanics, including measurements of left ventricular subendocardial and subepicardial function. What is the main finding and its importance? We provide new evidence that an increased contractility and untwisting efficiency, a key element of diastolic function, probably plays a key role in preservation of cardiac function during high-altitude trekking. Persistent increased loading conditions during several weeks at high altitude might have a key role in the appearance of left or right ventricular dysfunction.

Microbeam radiation therapy - grid therapy and beyond: a clinical perspective.

Microbeam irradiation is spatially fractionated radiation on a micrometer scale. Microbeam irradiation with therapeutic intent has become known as microbeam radiation therapy (MRT). The basic concept of MRT was developed in the 1980s, but it has not yet been tested in any human clinical trial, even though there is now a large number of animal studies demonstrating its marked therapeutic potential with an exceptional normal tissue sparing effect.

Towards the Design of a Patient-Specific Virtual Tumour.

The design of a patient-specific virtual tumour is an important step towards Personalized Medicine. However this requires to capture the description of many key events of tumour development, including angiogenesis, matrix remodelling, hypoxia, and cell state heterogeneity that will all influence the tumour growth kinetics and degree of tumour invasiveness. To that end, an integrated hybrid and multiscale approach has been developed based on data acquired on a preclinical mouse model as a proof of concept.

Multiparametric Magnetic Resonance Investigation of Brain Adaptations to 6 Days at 4350 m.

Objective: Hypoxic exposure in healthy subjects can induce acute mountain sickness including headache, lethargy, cerebral dysfunction, and substantial cerebral structural alterations which, in worst case, can lead to potentially fatal high altitude cerebral edema. Within this context, the relationships between high altitude-induced cerebral edema, changes in cerebral perfusion, increased brain parenchyma volume, increased intracranial pressure, and symptoms remain unclear.

Methods: In 11 subjects before and after 6 days at 4350 m, we performed multiparametric magnetic resonance investigations including anatomical, apparent diffusion coefficient and arterial spin labeling sequences.

Cerebral volumetric changes induced by prolonged hypoxic exposure and whole-body exercise.

The present study assessed the isolated and synergetic effects of hypoxic exposure and prolonged exercise on cerebral volume and subedema and symptoms of acute mountain sickness (AMS). Twelve healthy males performed three semirandomized blinded 11-hour sessions with (1) an inspiratory oxygen fraction (FiO2) of 12% and 4-hour cycling, (2) FiO2=21% and 4-hour cycling, and (3) FiO2=8.5% to 12% at rest (matching arterial oxygen saturation measured during the first hypoxic session).

Absolute perfusion measurements and associated iodinated contrast agent time course in brain metastasis: a study for contrast-enhanced radiotherapy.

Contrast-enhanced radiotherapy is an innovative treatment that combines the selective accumulation of heavy elements in tumors with stereotactic irradiations using medium energy X-rays. The radiation dose enhancement depends on the absolute amount of iodine reached in the tumor and its time course. Quantitative, postinfusion iodine biodistribution and associated brain perfusion parameters were studied in human brain metastasis as key parameters for treatment feasibility and quality.

Cerebral hemodynamic and ventilatory responses to hypoxia, hypercapnia, and hypocapnia during 5 days at 4,350 m.

This study investigated the changes in cerebral near-infrared spectroscopy (NIRS) signals, cerebrovascular and ventilatory responses to hypoxia and CO2 during altitude exposure. At sea level (SL), after 24 hours and 5 days at 4,350 m, 11 healthy subjects were exposed to normoxia, isocapnic hypoxia, hypercapnia, and hypocapnia. The following parameters were measured: prefrontal tissue oxygenation index (TOI), oxy- (HbO2), deoxy- and total hemoglobin (HbTot) concentrations with NIRS, blood velocity in the middle cerebral artery (MCAv) with transcranial Doppler and ventilation.

Photoactivation of gold nanoparticles for glioma treatment.

Unlabelled: Radiosensitization efficacy of gold nanoparticles (AuNPs) with low energy radiations (88 keV) was evaluated in vitro and in vivo on rats bearing glioma. In vitro, a significant dose-enhancement factor was measured by clonogenic assays after irradiation with synchrotron radiation of F98 glioma cells in presence of AuNPs (1.9 and 15 nm in diameter).

On the normalization of cerebral blood flow.

Cerebral blood flow (CBF) is the most common parameter for the quantification of brain's function. Literature data indicate a widespread dispersion of values that might be related to some differences in the measurement conditions that are not properly taken into account in CBF evaluation. Using recent high-resolution imaging of the complete cortical microvasculature of primate brain, we perform extensive numerical evaluation of the cerebral perfusion.

Synchrotron X-ray interlaced microbeams suppress paroxysmal oscillations in neuronal networks initiating generalized epilepsy.

Radiotherapy has shown some efficacy for epilepsies but the insufficient confinement of the radiation dose to the pathological target reduces its indications. Synchrotron-generated X-rays overcome this limitation and allow the delivery of focalized radiation doses to discrete brain volumes via interlaced arrays of microbeams (IntMRT). Here, we used IntMRT to target brain structures involved in seizure generation in a rat model of absence epilepsy (GAERS).

Intracerebral delivery of carboplatin in combination with either 6 MV photons or monoenergetic synchrotron X-rays are equally efficacious for treatment of the F98 rat glioma.

Background: The purpose of the present study was to compare side-by-side the therapeutic efficacy of a 6-day infusion of carboplatin, followed by X-irradiation with either 6 MV photons or synchrotron X-rays, tuned above the K-edge of Pt, for treatment of F98 glioma bearing rats.

Methods: Carboplatin was administered intracerebrally (i.c.

Ventilatory responses to exercise training in obese adolescents.

The aim of this study was to examine ventilatory responses to training in obese adolescents. We assessed body composition, pulmonary function and ventilatory responses (among which expiratory flow limitation and operational lung volumes) during progressive cycling exercise in 16 obese adolescents (OB) before and after 12 weeks of exercise training and in 16 normal-weight volunteers. As expected, obese adolescents' resting expiratory reserve volume was lower and inversely correlated with thoraco-abdominal fat mass (r = -0.

On the importance of the submicrovascular network in a computational model of tumour growth.

A computational model is potentially a powerful tool to apprehend complex phenomena like solid tumour growth and to predict the outcome of therapies. To that end, the confrontation of the model with experiments is essential to validate this tool. In this study, we develop a computational model specifically dedicated to the interpretation of tumour growth as observed in a mouse model with a dorsal skinfold chamber.

Cerebral perturbations during exercise in hypoxia.

Reduction of aerobic exercise performance observed under hypoxic conditions is mainly attributed to altered muscle metabolism due to impaired O(2) delivery. It has been recently proposed that hypoxia-induced cerebral perturbations may also contribute to exercise performance limitation. A significant reduction in cerebral oxygenation during whole body exercise has been reported in hypoxia compared with normoxia, while changes in cerebral perfusion may depend on the brain region, the level of arterial oxygenation and hyperventilation induced alterations in arterial CO(2).

Monochromatic minibeams radiotherapy: from healthy tissue-sparing effect studies toward first experimental glioma bearing rats therapy.

Purpose: The purpose of this study was to evaluate high-dose single fraction delivered with monochromatic X-rays minibeams for the radiotherapy of primary brain tumors in rats.

Methods And Materials: Two groups of healthy rats were irradiated with one anteroposterior minibeam incidence (four minibeams, 123 Gy prescribed dose at 1 cm depth in the brain) or two interleaved incidences (54 Gy prescribed dose in a 5 × 5 × 4.8 mm(3) volume centered in the right hemisphere), respectively.

Dual energy CT at the synchrotron: a piglet model for neurovascular research.

Background: Although the quality of imaging techniques available for neurovascular angiography in the hospital environment has significantly improved over the last decades, the equipment used for clinical work is not always suited for neurovascular research in animal models. We have previously investigated the suitability of synchrotron-based K-edge digital subtraction angiography (KEDSA) after intravenous injection of iodinated contrast agent for neurovascular angiography in radiography mode in both rabbit and pig models. We now have used the KEDSA technique for the acquisition of three-dimensional images and dual energy CT.