Metabolic responses to physical activity in subjects with type 1 diabetes

[eng] Type 1 diabetes mellitus is an autoimmune chronic disease that has undergone drastic changes on its clinical natural history in the last decades. Until the early XX century, the diagnosis of diabetes would mean a fatal outcome in few weeks or months. The evidence of hyperglycemia associated with abrupt polyuria, polydipsia, polyphagia and weight loss in a child or a young person determined a diagnosis of failure of insulin secretion, metabolic catabolism and death. The introduction of treatments with exogenous insulin was the first important change in the natural clinical history of diabetes. Subjects affected by diabetes experienced then a hope of treatment and life. The main initial concern of physicians and scientists was to avoid important episodes of hypo or hyperglycemia, which could lead to hypoglycemic coma or diabetic ketoacidosis. Different classes of insulins were tested and used with success, offering better life expectancy for the affected persons. In parallel with the provided increase of life expectancy, chronic complications related to diabetes were prone to appear. Those patients who, at that moment, benefit from the exogenous insulin, but maintained many episodes of hyperglycemia and glycemia fluctuations, developed chronic complications leading to blindness, renal failure, limbs amputations and/or cardiovascular complications as heart attack or stroke. Aware of the consequences of hyperglycemia, researchers started to design studies promoting a more strict control of glucose levels, with the intention of minimizing chronic complications related to diabetes. Studies for type 1 diabetes (T1D) like DCCT, published in 1993 (The Diabetes Control and Complications Trial Research Group, 1993) and its follow-up EDIC (Nathan et al., 2005), and others alike for type 2 diabetes (T2D) (UK Prospective Diabetes Study, UKPDS Group 1998), proved the reduction of complications rates and marked a new change in the natural clinical history of diabetes. Recently, tighter glycemic control became possible with the help of new insulins, insulin infusers, glucose sensors and nutrition research. The incidence of retinopathy, nephropathy, neuropathy and their consequent serious outcomes as blindness, end renal stage disease and lower limb amputations, reduced in the past two decades, as described in the US patients with diabetes (Gregg et al., 2014). The excess risk of mortality in individuals over 20 years old with diabetes (T1D and T2D) if compared with the risk of individuals without diabetes has decreased over time in both Canada and the UK, as shown in data recently published (M Lind et al., 2013). This may be, in part, due to the earlier diagnosis, as well as to improvements in diabetes care (M Lind et al., 2013). In patients with T1D, a reduction of all-cause mortality and also of specific cardiovascular mortality could be verified, especially if associated with a good glycemic control; these rates, nevertheless, are still the double of the ones seen in subjects without diabetes (Marcus Lind et al., 2014). Physical activity is considered as a health promoter procedure for general population and a therapeutic tool for prevention and/or treatment of several chronic diseases, like T2D, cardiovascular disease or cancer. Persons with T1D are stimulated to participate in exercise training programs and competition events. Nowadays, with the current knowledge, several elite athletes with T1D are able to compete in the same categories that the ones without diabetes, but requiring for that a strict balance among insulin adjustments, carbohydrate intake and physical activity characteristics. Many questions may be formulated at the present time: are persons with T1D being beneficiated from physical activity as persons without diabetes? Do the subjects with T1D present the same physical conditions for exercise performance than the non-diabetic ones? Do they present different metabolic response when performing a session of exercise? Does physical activity improve lipoprotein profile generating cardiovascular benefits for the subjects with T1D? What are the characteristics of muscular composition of patients with T1D, and are they different from subjects without diabetes? What are the factors that could be interfering? These questions are discussed in the present thesis. Some answers were achieved and some other questions emerged. Nowadays, the availability of new technological approaches, the improvements on basic research, and the possibility to integrate the information of basic research with clinical research are improving the knowledge in biomedical science. A better understanding of physiopathology can be obtained, and with it, a better care, a better quality of life, and longer life expectancy can be offered to persons who have type 1 diabetes

Influence of warming and atmospheric circulation changes on multidecadal European flood variability

International audienceEuropean flood frequency and intensity change on a multidecadal scale. Floods were more frequent in the 19th (central Europe) and early 20th century (western Europe) than during the mid-20th century and again more frequent since the 1970s. The causes of this variability are not well understood and the relation to climate change is unclear. Palaeoclimate studies from the northern Alps suggest that past flood-rich periods coincided with cold periods. In contrast, some studies suggest that more floods might occur in a future, warming world. Here we address the contribution of atmospheric circulation and of warming to multidecadal flood variability. For this, we use long series of annual peak streamflow, daily weather data, reanalyses, and reconstructions. We show that both changes in atmospheric circulation and moisture content affected multidecadal changes of annual peak streamflow in central and western Europe over the past two centuries. We find that during the 19th and early 20th century, atmospheric circulation changes led to high peak values of moisture flux convergence. The circulation was more conducive to strong and long-lasting precipitation events than in the mid-20th century. These changes are also partly reflected in the seasonal mean circulation and reproduced in atmospheric model simulations, pointing to a possible role of oceanic variability. For the period after 1980, increasing moisture content in a warming atmosphere led to extremely high moisture flux convergence. Thus, the main atmospheric driver of flood variability changed from atmospheric circulation variability to water vapour increase.La fréquence et l'intensité des inondations en Europe changent à une échelle multidécennale. Les inondations étaient plus fréquentes au 19ème (Europe centrale) et au début du 20ème siècle (Europe occidentale) qu'au milieu du 20ème siècle et à nouveau plus fréquentes depuis les années 1970. Les causes de cette variabilité ne sont pas bien comprises et la relation avec le changement climatique n'est pas claire. Les études paléoclimatiques menées dans les Alpes du Nord suggèrent que les périodes passées riches en inondations coïncidaient avec des périodes froides. En revanche, certaines études suggèrent que davantage d'inondations pourraient se produire dans un monde futur en réchauffement. Nous abordons ici la contribution de la circulation atmosphérique et du réchauffement à la variabilité multidécennale des inondations. Pour cela, nous utilisons de longues séries de débit maximal annuel, des données météorologiques quotidiennes, des réanalyses et des reconstructions climatiques. Nous montrons que les changements de la circulation atmosphérique et du contenu en humidité ont affecté les changements multidécennaux du débit maximal annuel en Europe centrale et occidentale au cours des deux derniers siècles. Nous constatons qu'au cours du 19ème et du début du 20ème siècle, les changements de la circulation atmosphérique ont conduit à des valeurs de pointe élevées de convergence du flux d'humidité. La circulation était plus propice à des événements de précipitations forts et durables qu'au milieu du 20e siècle. Ces changements se reflètent également en partie dans la circulation moyenne saisonnière et sont reproduits dans les simulations des modèles atmosphériques, ce qui indique un rôle possible de la variabilité océanique. Pour la période après 1980, l'augmentation de la teneur en humidité dans une atmosphère qui se réchauffe a conduit à une convergence extrêmement élevée des flux d'humidité. Ainsi, le principal moteur atmosphérique de la variabilité des crues est passé de la variabilité de la circulation atmosphérique à l'augmentation de la vapeur d'eau

Differences in Physiological Responses to Cardiopulmonary Exercise Testing in Adults With and Without Type 1 Diabetes: A Pooled Analysis

OBJECTIVE To investigate physiological responses to cardiopulmonary exercise (CPX) testing in adults with type 1 diabetes compared with age-, sex-, and BMI-matched control participants without type 1 diabetes.RESEARCH DESIGN AND METHODS We compared results from CPX tests on a cycle ergometer in individuals with type 1 diabetes and control participants without type 1 diabetes. Parameters were peak and threshold variables of VO2, heart rate, and power output. Differences between groups were investigated through restricted maximum likelihood modeling and post hoc tests. Differences between groups were explained by stepwise linear regressions (P < 0.05).RESULTS Among 303 individuals with type 1 diabetes (age 33 [interquartile range 22; 43] years, 93 females, BMI 23.6 [22; 26] kg/m2, HbA1c 6.9% [6.2; 7.7%] [52 (44; 61) mmol/mol]), VO2peak (32.55 [26.49; 38.72] vs. 42.67 ± 10.44 mL/kg/min), peak heart rate (179 [170; 187] vs. 184 [175; 191] beats/min), and peak power (216 [171; 253] vs. 245 [200; 300] W) were lower compared with 308 control participants without type 1 diabetes (all P < 0.001). Individuals with type 1 diabetes displayed an impaired degree and direction of the heart rate-to-performance curve compared with control participants without type 1 diabetes (0.07 [−0.75; 1.09] vs. 0.66 [−0.28; 1.45]; P < 0.001). None of the exercise physiological responses were associated with HbA1c in individuals with type 1 diabetes.CONCLUSIONS Individuals with type 1 diabetes show altered responses to CPX testing, which cannot be explained by HbA1c. Intriguingly, the participants in our cohort were people with recent-onset type 1 diabetes; heart rate dynamics were altered during CPX testing

Avaliação da resposta autonômica simpática à exposição da face ao frio de indivíduos normais e de pacientes com diabetes mellitus com e sem microangiopatia

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Avaliação da resposta autonômica simpática à exposição da face ao frio de indivíduos normais e de pacientes com diabetes mellitus com e sem microangiopatia

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ModE-RA: a global monthly paleo-reanalysis of the modern era 1421 to 2008.

The Modern Era Reanalysis (ModE-RA) is a global monthly paleo-reanalysis covering the period between 1421 and 2008. To reconstruct past climate fields an offline data assimilation approach is used, blending together information from an ensemble of transient atmospheric model simulations and observations. In the early period, ModE-RA utilizes natural proxies and documentary data, while from the 17th century onward instrumental measurements are also assimilated. The impact of each observation on the reconstruction is stored in the observation feedback archive, which provides additional information on the input data such as preprocessing steps and the regression-based forward models. The monthly resolved reconstructions include estimates of the most important climate fields. Furthermore, we provide a reconstruction, ModE-RAclim, which together with ModE-RA and the model simulations allows to disentangle the role of observations and model forcings. ModE-RA is best suited to study intra-annual to multi-decadal climate variability and to analyze the causes and mechanisms of past extreme climate events