463 research outputs found

    Numerical and in vitro experimental study of arterial deformation and buckling under hypertension and atherosclerotic conditions

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    Cardiovascular diseases remain the major cause of mortality worldwide. Pathologies of the vasculature such as atherosclerosis are often related to biochemical and genetic factors as well as mechanical effects that strongly change the function and shape of arteries. The present work is part of a general research project which aims to better understand the mechanical mechanisms responsible for atherosclerotic plaque formation and rupture. The chosen approach is to use numerical fluidstructure interaction (FSI) methods to study the relative influence of hemodynamic parameters on the structural stresses generated on plaques. To this aim, a numerical study of a simplified straight vessel exposed to lumen pressure was investigated under quiescent and steady flow conditions. As the internal pressure or the steady velocity increases, the vessel buckles lead-ing to a non-linear large deformation behaviour. The results have been validated using theoretical predictions for the buckling thresholds. Further studies on idealised cardiovascular conditions such as stenosis (i.e., lumen constriction) or aneurysm like (i.e., arterial wall expansion) formation have also been performed

    Endocrine treatment of gender-dysphoric/gender-incongruent persons : an Endocrine Society clinical practice guideline

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    Objective: To update the "Endocrine Treatment of Transsexual Persons: An Endocrine Society Clinical Practice Guideline," published by the Endocrine Society in 2009. Participants: The participants include an Endocrine Societyappointed task force of nine experts, a methodologist, and a medical writer. Evidence: This evidence-based guideline was developed using the Grading of Recommendations, Assessment, Development, and Evaluation approach to describe the strength of recommendations and the quality of evidence. The task force commissioned two systematic reviews and used the best available evidence from other published systematic reviews and individual studies. Consensus Process: Group meetings, conference calls, and e-mail communications enabled consensus. Endocrine Society committees, members and cosponsoring organizations reviewed and commented on preliminary drafts of the guidelines. Conclusion: Gender affirmation is multidisciplinary treatment in which endocrinologists play an important role. Gender-dysphoric/gender-incongruent persons seek and/or are referred to endocrinologists to develop the physical characteristics of the affirmed gender. They require a safe and effective hormone regimen that will (1) suppress endogenous sex hormone secretion determined by the persons genetic/gonadal sex and (2) maintain sex hormone levels within the normal range for the persons affirmed gender. Hormone treatment is not recommended for prepubertal gender-dysphoric/gender-incongruent persons. Those clinicians who recommend gender-affirming endocrine treatments-appropriately trained diagnosing clinicians (required), a mental health provider for adolescents (required) and mental health professional for adults (recommended)-should be knowledgeable about the diagnostic criteria and criteria for gender-affirming treatment, have sufficient training and experience in assessing psychopathology, and be willing to participate in the ongoing care throughout the endocrine transition. We recommend treating gender-dysphoric/gender-incongruent adolescents who have entered puberty at Tanner Stage G2/B2 by suppression with gonadotropin-releasing hormone agonists. Clinicians may add gender-affirming hormones after a multidisciplinary team has confirmed the persistence of gender dysphoria/gender incongruence and sufficient mental capacity to give informed consent to this partially irreversible treatment. Most adolescents have this capacity by age 16 years old. We recognize that there may be compelling reasons to initiate sex hormone treatment prior to age 16 years, although there is minimal published experience treating prior to 13.5 to 14 years of age. For the care of peripubertal youths and older adolescents, we recommend that an expert multidisciplinary team comprised of medical professionals and mental health professionals manage this treatment. The treating physician must confirm the criteria for treatment used by the referring mental health practitioner and collaborate with them in decisions about gender-affirming surgery in older adolescents. For adult gender-dysphoric/gender-incongruent persons, the treating clinicians (collectively) should have expertise in transgender-specific diagnostic criteria, mental health, primary care, hormone treatment, and surgery, as needed by the patient. We suggest maintaining physiologic levels of gender-appropriate hormones and monitoring for known risks and complications. When high doses of sex steroids are required to suppress endogenous sex steroids and/or in advanced age, clinicians may consider surgically removing natal gonads along with reducing sex steroid treatment. Clinicians should monitor both transgender males (female to male) and transgender females (male to female) for reproductive organ cancer risk when surgical removal is incomplete. Additionally, clinicians should persistently monitor adverse effects of sex steroids. For gender-affirming surgeries in adults, the treating physician must collaborate with and confirm the criteria for treatment used by the referring physician. Clinicians should avoid harming individuals (via hormone treatment) who have conditions other than gender dysphoria/gender incongruence and who may not benefit from the physical changes associated with this treatment

    Novel Leptin Receptor Mutations Identified in Two Girls with Severe Obesity Are Associated with Increased Bone Mineral Density

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    Background: Recessive mutations in the leptin receptor (LEPR) are a rare cause of hyperphagia and severe early-onset obesity. To date, the phenotype has only been described in 25 obese children, some of whom also had altered immune function, hypogonadotropic hypogonadism, reduced growth hormone secretion, hypothalamic hypothyroidism or reduced adult height. We provide a detailed description of the phenotype of 2 affected girls to add to this knowledge. Methods: Whole-exome sequencing and targeted sequencing were used to detect the LEPR mutations. RNA analysis was performed to assess the effect of splice-site mutations. Results: In 2 unrelated girls with severe obesity, three novel LEPR mutations were detected. Longitudinal growth data show normal childhood growth, and in the older girl, a normal adult height despite hypogonadotropic hypogonadism and the lack of an obvious pubertal growth spurt. Bone age is remarkably advanced in the younger (prepubertal) girl, and bone mineral density (BMD) is high in both girls, which might be directly or indirectly related to leptin resistance. Conclusion: The spectrum of clinical features of LEPR deficiency may be expanded with increased BMD. Future observations in LEPR-deficient subjects should help further unravel the role of leptin in human bone biology

    Birth weight in different etiologies of disorders of sex development

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    Context: It is well established that boys are heavier than girls at birth. Although the cause of birth weight (BW) difference is unknown, it has been proposed that it could be generated from prenatal androgen action. Objective: The aim of the current study was to determine the BW of children with disorders of sex development (DSD) of different etiologies and to evaluate the effects of androgen action on BW. Methods: Data regarding diagnosis, BW, gestational age, karyotype, and concomitant conditions were collected from the InternationalDisorders of SexDevelopment (I-DSD) Registry (www.i-dsd).BWstandard deviation score was calculated according to gestational age. Cases were evaluated according to disorder classification in I-DSD (i.e., disorders of gonadal development, androgen excess, androgen synthesis, androgen action, nonspecific disorder of undermasculinization groups, and Leydig cell defect). Results: A total of 533 cases were available; 400 (75%) cases were 46,XY, and 133 (25%) cases were 46,XX. Eighty cases (15%) were born small for gestational age (SGA). Frequency of SGA was higher in the 46,XY group (17.8%) than in the 46,XX (6.7%) group (P = 0.001). Mean BW standard deviation scores of cases with androgen excess and androgen deficiency [in disorders of gonadal development, androgen synthesis, and Leydig cell defect groups and androgen receptor gene (AR)mutation-positive cases in disorders of androgen action groups]were similar to normal childrenwith the same karyotype. SGA birth frequency was higher in the AR mutation-negative cases in disorders of androgen action group and in the nonspecific disorders of the undermasculinization group. Conclusions: BWdimorphism is unlikely to be explained by fetal androgen action per se. 46,XY DSDs due to nonspecific disorders of undermasculinizationare more frequently associatedwithfetal growth restriction, SGA, and concomitant conditions

    Trajectories of Adolescents Treated with Gonadotropin-Releasing Hormone Analogues for Gender Dysphoria

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    Gonadotropin-releasing hormone analogues (GnRHa) are recommended as initial treatment for adolescents diagnosed with gender dysphoria, providing time to follow gender identity development and consider further treatment wishes without distress caused by unwant
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