The mechanism that controls the selective vulnerability of striatal neurons in Huntington's disease is unclear. Brain-derived neurotrophic factor (BDNF) protects striatal neurons and is regulated by Huntingtin through the interaction with the neuron-restrictive silencer factor. Here, we demonstrate that the downregulation of BDNF by mutant Huntingtin depends on the length and levels of expression of the CAG repeats in cell cultures. To analyze the functional effects of these changes in BDNF in Huntington's disease, we disrupted the expression of bdnf in a transgenic mouse model by cross-mating bdnf ϩ/Ϫ mice with R6/1 mice. Thus, we compared transgenic mice for mutant Huntingtin with different levels of BDNF. Using this double mutant mouse line, we show that the deficit of endogenous BDNF modulates the pathology of Huntington's disease. The decreased levels of this neurotrophin advance the onset of motor dysfunctions and produce more severe uncoordinated movements. This behavioral pathology correlates with the loss of striatal dopamine and cAMPregulated phosphoprotein-32-positive projection neurons. In particular, the insufficient levels of BDNF cause specific degeneration of the enkephalinergic striatal projection neurons, which are the most affected cells in Huntington's disease. This neuronal dysfunction can specifically be restored by administration of exogenous BDNF.Therefore, the decrease in BDNF levels plays a key role in the specific pathology observed in Huntington's disease by inducing dysfunction of striatal enkephalinergic neurons that produce severe motor dysfunctions. Hence, administration of exogenous BDNF may delay or stop illness progression.

Objective: To present the adaptations to treatment protocols made in a child and adolescent eating disorders (ED) unit during the eight-week confinement period mandated in response to the COVID-19 pandemic and examine clinical and treatment variables in the outpatient, day hospital, and inpatient care programs. Method: Description of the implementation of a combined teletherapy program for outpatient and day-hospital patients and the adaptations made to the inpatient protocol. Retrospective review of medical records and analysis of general and specific variables related to the pandemic and confinement. Results: We held 1,329 (73.10%) telehealth consultations and 489 (26.9%) faceto-face outpatient visits with 365 patients undergoing treatment in the outpatient clinic or day hospital. Twenty-eight (7.67%) were initial evaluations. Twenty-two patients were newly admitted and 68 ED-related emergencies were attended. Almost half of the children and adolescents studied experienced reactivation of ED symptoms despite treatment, and severe patients (25%) presented self-harm and suicide risk. Conclusions: The implementation of a combined teletherapy program has enabled continuity of care during confinement for children and adolescents with ED. Delivery of treatment to adolescents in the day hospital program posed the biggest challenge due to their greater degrees of severity and higher hospitalization rates. An adapted inpatient program should be maintained throughout confinement, as the need for hospitalization of children and adolescents with ED does not decrease with lockdown.

Objective: Our aim was to compare physical activity and biochemical markers with bone mineral acquisition in rhythmic gymnasts and ballet dancers. Methods: Weight, height, body mass index, nutritional intake, bone age and menstrual histories were analyzed in nine rhythmic gymnasts, twelve ballet dancers and fourteen controls. Bone mineral density (BMD) was assessed by X-ray absorptiometry at the lumbar spine, hip and radius. Bone alkaline phosphatase (bAP) and amino-terminal propeptide of procollagen I (PNIP) in serum and urinary a-isomer of the carboxy-terminal telopeptide of collagen I (a-CTX) were measured. Results: Bone age was delayed 2 years and mean age at menarche was 15^0.9 years in rhythmic gymnasts and 13.7^1 years in ballet dancers, compared with 12.5^1 years in controls. Trocanteric and femoral neck BMD was significantly higher in rhythmic gymnasts compared with ballet dancers and controls. Right forearm (non-loaded zone) BMD was significantly decreased in rhythmic gymnasts and ballet dancers compared with controls. All subjects had normal bAP and PNIP levels, but the a-CTX/creatinine (Cr) ratio was increased in rhythmic gymnasts (P , 0.001) with an inverse correlation between right forearm BMD and the a-CTX/Cr ratio (r ¼ 2 0.74, P , 0.001). Serum leptin levels were decreased in rhythmic gymnasts and ballet dancers. Rhythmic gymnasts had a positive correlation between right forearm BMD and leptin levels (r ¼ 0.85, P , 0.001). Conclusions: Decreased bone mass in rhythmic gymnasts could be partially explained by an increase in bone resorption. Serum leptin levels could be implicated in the pubertal delay and be a good marker of bone mass in these subjects. European Journal of Endocrinology 151 491-496

There is still controversy over the impact of diabetes control and duration on bone mass and growth parameters in children and adolescents with insulin-dependent diabetes mellitus (IDDM). The aim of this study was to assess bone mineral density (BMD) at axial and appendicular sites, in children with noncomplicated IDDM of recent onset, and its relation to metabolic control and auxological parameters (weight, height, and puberal stage). Fifty-five young Spanish IDDM, otherwise healthy patients (26 males, aged (SD 9.7 +/- 4.3 years) and 29 females, aged (SD 11.2 +/- 3.8 years) were studied. Duration of diabetes was 1-13.8 years. Two hundred eighty-two age-matched, healthy, Spanish children served as controls. HbA1 was assayed by high pressure liquid chromatography (HPLC) and BMD was measured using dual X-ray absorptiometry (DXA) densitometry at the spine and forearm. Results showed a Gaussian BMD distribution of patients according to sex and age, without sexual-stage differences. There was no correlation between BMD and glycated hemoglobin (average life disease or last HbA1 values) or duration of the disease; moreover, no differences in bone mass were found between <3 and >/=3 years of disease duration. Diabetes impact index (mean HbA1 x duration of disease in months) showed no significant influence of diabetes control on BMD. We could not demonstrate any impact of diabetes on BMD and growth parameters in children with IDDM of short duration.

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