Résumé La survenue d’une acidose lactique dans l’asthme aigu grave (AAG) est classique chez l’adulte mais peu décrite chez l’enfant. Sa reconnaissance peut avoir des conséquences sur la prise en charge thérapeutique de la crise d’asthme. Une petite fille de 2 ans a été hospitalisée en réanimation pédiatrique pour un AAG, traité par oxygénothérapie à haut débit, méthylprednisolone et salbutamol par voie intraveineuse. Elle a présenté une acidose métabolique (pH = 7,29) avec hypocapnie (26 mmHg), chute des bicarbonates (12 mmol/L), trou anionique (20 mmol/L) et augmentation des lactates (8 mmol/L). La recherche d’une maladie métabolique sous-jacente a été négative. L’évolution a été favorable avec amélioration spontanée de l’acidose lactique permettant la sortie de l’unité de réanimation après 72 heures. L’origine d’une acidose lactique au cours de l’AAG est multifactorielle. Bien que sa résolution soit spontanée, il est essentiel de la reconnaître car elle peut modifier la symptomatologie respiratoire et conduire à une escalade thérapeutique inappropriée. Summary Lactic acidosis is a recognized event in adult patients with acute severe asthma (ASA). Only a few cases have been reported in children. Hereinafter is reported the case of a 2-year-old girl hospitalized in the pediatric intensive care unit for ASA, which was treated with high-flow oxygen therapy and intravenous methylprednisolone and salbutamol. During hospitalization, she had metabolic acidosis with a 7.29 pH, a 26 mmHg hypocapnia, and a decrease in bicarbonates to 12 mmol/L. The anion gap was increased to 20 mmol/L and lactates to 8 mmol/L. The work-up for a congenital metabolic disease was normal. Progression was propitious with spontaneous improvement of lactic acidosis, and the child was discharged from the intensive care unit after 72 h. The origin of lactic acidosis during ASA seems to be multifactorial. Although its recovery can be spontaneous, it is important to know how to identify it because it can worsen respiratory symptoms and can lead to incongruous therapeutic escalation.

Introduction The occurrence of life threatening severe respiratory failure in patients with an incurable illness may be an indication for the use of noninvasive ventilation (NIV). State of the art Two approaches are associated with the use of NIV in palliative care settings. In the “palliative approach”, NIV is proposed for patients with end stage of chronic respiratory failure and do-not-tracheostomize orders as a ceiling of care. In the “palliative and probably curative” approach, NIV may help patients with do-not-intubate orders or to forego endotracheal intubation. This review provides some guidelines for clinicians responsible for patients with incurable illness, to help to guide and anticipate the medical management if acute respiratory failure (ARF) develops. Conclusions and perspectives NIV may palliate symptoms in patients near the end of life. In the case of severe ARF in patients with do-not-intubate orders, NIV may avoid the need for endotracheal mechanical ventilation, most often in patients with COPD or cardiogenic pulmonary oedema. NIV may help some patients to forego endotracheal intubation. Future studies are needed to examine the attitudes of patients and families to this intervention.

Introduction The occurrence of life threatening severe respiratory failure in patients with an incurable illness may be an indication for the use of noninvasive ventilation (NIV). State of the art Two approaches are associated with the use of NIV in palliative care settings. In the “palliative approach”, NIV is proposed for patients with end stage of chronic respiratory failure and do-not-tracheostomize orders as a ceiling of care. In the “palliative and probably curative” approach, NIV may help patients with do-not-intubate orders or to forego endotracheal intubation. This review provides some guidelines for clinicians responsible for patients with incurable illness, to help to guide and anticipate the medical management if acute respiratory failure (ARF) develops. Conclusions and perspectives NIV may palliate symptoms in patients near the end of life. In the case of severe ARF in patients with do-not-intubate orders, NIV may avoid the need for endotracheal mechanical ventilation, most often in patients with COPD or cardiogenic pulmonary oedema. NIV may help some patients to forego endotracheal intubation. Future studies are needed to examine the attitudes of patients and families to this intervention.

Introduction The occurrence of life threatening severe respiratory failure in patients with an incurable illness may be an indication for the use of noninvasive ventilation (NIV). State of the art Two approaches are associated with the use of NIV in palliative care settings. In the “palliative approach”, NIV is proposed for patients with end stage of chronic respiratory failure and do-not-tracheostomize orders as a ceiling of care. In the “palliative and probably curative” approach, NIV may help patients with do-not-intubate orders or to forego endotracheal intubation. This review provides some guidelines for clinicians responsible for patients with incurable illness, to help to guide and anticipate the medical management if acute respiratory failure (ARF) develops. Conclusions and perspectives NIV may palliate symptoms in patients near the end of life. In the case of severe ARF in patients with do-not-intubate orders, NIV may avoid the need for endotracheal mechanical ventilation, most often in patients with COPD or cardiogenic pulmonary oedema. NIV may help some patients to forego endotracheal intubation. Future studies are needed to examine the attitudes of patients and families to this intervention.

Despite the increasing use of speleothems as high-resolution archives of past climate proxies, few efforts have been made to improve understanding of diagenetic pathways affecting this material and to assess the degree of postdepositional transformation of initial features, including associated geochemical signatures. To provide criteria for distinguishing primary (spelean growth history) and secondary (spelean diagenetic history) features, this study documents a process-based approach combining mineralogical, textural, and geochemical data at different scales to characterize various diagenetic processes undergone by aragonite and calcite speleothems from the Pont-de-Ratz Cave (Herault, S. France). Results show that the initial precipitation of carbonate minerals forming the stalagmites (vadose precipitation) is represented alternatively by aragonite and calcite and consists of two types of primary aragonite and a primary columnar calcite. Four different types of growth interruption and inclusion horizons are evident, and attest to the discontinuous growth of stalagmites in this cave. Postdepositional diagenetic processes include void-filling calcite cementation, selective dissolution of either aragonite or calcite, and recrystallization. Recrystallization processes include 1) textural change of original aragonite precipitates (isomineralogical recrystallization), and 2) two distinct types of aragonite-to-calcite recrystallization. These results highlight the diversity of potential synformational and postformational processes controlling the formation and evolution of speleothems and their impact on the geochemical properties of the primary and secondary carbonate phases, and the potential importance in paleoclimatic interpretation.

Calpains are a large family of cytosolic cysteine proteases composed of at least fourteen distinct isoforms. The family can be divided into two groups on the basis of distribution: ubiquitous and tissue-specific. Our current knowledge about calpains properties apply mainly to the ubiquitous isozymes, micro- and milli-calpain (classic calpains). These forms are activated after autolysis. Translocation and subsequent interactions with phospholipids of these enzymes increase their activity. Calpains are able to cleave a subset of substrates, as enzymes, structural and signalling proteins. Cardiac pathologies, such as heart failure, atrial fibrillation or clinical states particularly ischemia reperfusion, are associated with an increase of cytosolic calcium and in this regards, calpain activation has been evoked as one of the mediators leading to myocardial damage. Calpain activities have been shown to be increased in hearts experimentally subjected to ischemia reperfusion or during hypertrophy, but also in atrial tissue harvested from patients suffering from atrial fibrillations. These activities have been related to an increase of the proteolysis of different myocardial components, particularly, troponins, which are major regulators of the contraction of cardiomyocytes. Moreover, recent works have demonstrated that calpains are involved in the development of myocardial cell death by necrosis or apoptosis.

In order to predict the ability of a material to support the load applied at asperities, the flow stress of the surface regions must be known. However, there is little quantitative data on the work hardening behaviour resulting from plastic sliding contact. Both linear hardening and the achievement of a saturation flow stress have been predicted. Two binary Al alloys, Al-4wt.%Cu and Al-11.7wt.%Si, were worn against a cast iron disc in a tri-pin-on-disc machine, under dry sliding conditions at 1 m s−1 over the load range 6-40 N. Detailed transmission electron microscopy was performed on cross-sections taken from worn surfaces of both materials. The subgrain size was found to decrease substantially as the surface was approached for both alloys. In the Al-Si alloy, the Si particle size was also found to decrease as the surface was approached. Taper sections were taken parallel to the sliding direction and the microhardness was measured as a function of depth below the worn surface. The equivalent strain was measured from the displacement of prominent microstructural features such as grain boundaries. This allowed stress-strain curves to be constructed for the worn surface of the two materials. The stress-strain data were interpreted in relation to established work hardening laws, and correlated with the subgrain size. The maximum flow stress observed correlated with a minimum subgrain width of approximately 0.2 μm in the Al-Cu and approximately 0.4 μm in the Al-Si alloy.