Confidence intervals for point-of-stabilization of content uniformity.

Within the framework of continuous pharmaceutical manufacturing, we are interested in statistical modeling of the initial behavior of the production line. Assuming a gradually changing sequence of a suitable product quality characteristic (e.g., the content uniformity), we estimate the so-called point-of-stabilization (PoSt) and construct corresponding confidence regions based on appropriate asymptotic distributions and bootstrap. We investigate linear, quadratic, and nonlinear gradual change models both in homoscedastic and heteroscedastic setup. We propose a new nonlinear Emax gradual change model and show that it is applicable even if the true model is linear. Asymptotic distribution of the PoSt estimator is known only in a homoscedastic linear and quadratic model and, therefore, bootstrap approximations are used to construct one-sided PoSt confidence intervals.

Muscle function in Turner syndrome: normal force but decreased power.

OBJECTIVE: Although hypogonadism and SHOX gene haploinsufficiency likely cause the decreased bone mineral density and increased fracture rate associated with Turner syndrome (TS), the exact mechanism remains unclear. We tested the hypothesis that muscle dysfunction in patients with TS contributes to increased fracture risk. The secondary aim was to determine whether menarche, hormone therapy duration, positive fracture history and genotype influence muscle function parameters in patients with TS. DESIGN: A cross-sectional study was conducted in a single university hospital referral centre between March 2012 and October 2013. PATIENTS: Sixty patients with TS (mean age of 13·7 ± 4·5 years) were compared to the control group of 432 healthy girls. MEASUREMENTS: A Leonardo Mechanograph(®) Ground Reaction Force Platform was used to assess muscle force (Fmax ) by the multiple one-legged hopping test and muscle power (Pmax ) by the single two-legged jump test. RESULTS: While the Fmax was normal (mean weight-specific Z-score of 0·11 ± 0·77, P = 0·27), the Pmax was decreased in patients with TS (Z-score of -0·93 ± 1·5, P < 0·001) compared with healthy controls. The muscle function parameters were not significantly influenced by menarcheal stage, hormone therapy duration, fracture history or genotype (linear regression adjusted for age, weight and height; P > 0·05 for all). CONCLUSION: Fmax , a principal determinant of bone strength, is normal in patients with TS. Previously described changes in bone quality and structure in TS are thus not likely related to inadequate mechanical loading but rather represent a primary bone deficit. A decreased Pmax indicates impaired muscle coordination in patients with TS.

Increase in lumbar spine but not distal radius bone mineral density in adults after pancreas kidney transplantation.

Osteoporosis occurs in every third individual after simultaneous pancreas kidney transplantation (SPKT). Currently used bone measures insufficiently predict their fracture risk. Lumbar spine Trabecular bone score (TBS) and distal radius areal and volumetric bone mineral density (BMD) were monitored for the first time in patients with type 1 diabetes and chronic renal failure after SPKT with steroid-sparing protocol. In 33 subjects (mean age 43.4 ± 9.8 years), dual-energy X-ray absorptiometry and peripheral quantitative computed tomography were performed just after SPKT (baseline) and one and three years later. While TBS Z-scores increased (-1.1 ± 1.2 and -0.3 ± 1.0; p˂0.001, at baseline and year three, respectively), trabecular volumetric BMD Z-scores at distal radius metaphysis did not change during the study (-1.3 ± 1.3 and -1.3 ± 1.0; p = 0.38). Similarly, areal BMD Z-scores increased at lumbar spine, total hip and femoral neck (all p < 0.01), but not at the distal radius. SPKT induced bone measures' improvement at lumbar spine and hip but not at distal radius. Before suggesting changes in current clinical care, predictive value of individual bone measures or its combination for fracture risk assessment remains to be elucidated.

Bone geometry and volumetric bone mineral density in girls with Turner syndrome of different pubertal stages.

OBJECTIVE: An increased rate of fractures has been reported in patients with Turner syndrome (TS). We aimed to assess bone geometry and volumetric bone mineral density (vBMD) at the radius in girls with TS and to evaluate the relationships between bone parameters and fracture history. METHODS AND DESIGN: Sixty-seven girls with TS aged 6-19 years treated currently or in the past with growth hormone (GH) and/or oestrogens were examined using peripheral quantitative computed tomography. Results were compared to reference data. RESULTS: Cortical area and cortical thickness were low in all age groups (all P<0·001). Height-adjusted total bone area at the diaphysis was increased in prepubertal and postpubertal girls (mean Z-score 1·0, P<0·05 for both) and normal in the pubertal group (mean Z-score 0·1). Cortical vBMD was decreased (mean age-specific Z-scores -2·0, -1·6 and -1·0 for prepubertal, pubertal and postpubertal groups, respectively, P<0·01 for all groups). Height- , age- and cortical thickness-adjusted cortical vBMD was positively correlated to the duration of GH therapy (P=0·012) and to oestrogen administration (P=0·047). Girls with a history of fractures had lower total vBMD at the metaphysis compared to nonfractured TS girls (mean Z-scores -1·7 vs-0·9, P=0·04). CONCLUSIONS: There is a cortical bone deficit in girls with TS characterized by low cortical area, thin cortex and probably decreased cortical vBMD. Early commencement of GH therapy, as well as oestrogen replacement, is associated with higher cortical vBMD. Further studies should investigate the potential causality of this relation.

A 6-Year Follow-Up of Fracture Incidence and Volumetric Bone Mineral Density Development in Girls With Turner Syndrome.

Context: Patients with Turner syndrome (TS) are at risk for osteoporotic fractures. Objective: The aims of this study were to assess the incidence of clinically important fractures in girls with TS and prospectively describe the development of volumetric bone mineral density (BMD). Design: Peripheral quantitative computerized tomography (pQCT) of the radius every other year over the 6 years of observation. Setting: Government-funded university referral center. Participants: Thirty-two girls with TS, aged 6 to 16 years, were included in the analyses. Fracture incidence was compared with the data in the general population. Bone density and strength were compared with data from 185 healthy girls. Outcomes: The main clinical outcome was the fracture occurrence. The secondary outcomes were the changes in Z-scores of the bone parameters. Results: Three girls with TS sustained four fractures during 6 years of observation. The fracture rate in TS was not substantially higher than the downward-biased fracture-rate estimate from age-matched, healthy controls (P = 0.48). Whereas the trabecular BMD Z-score decreased with age (ß estimate -0.21 ± 0.04, P < 0.001), total bone cross-sectional area correspondingly increased (+0.16 ± 0.04, P < 0.001), which led to normal bone strength. A positive history of incident fractures was not significantly associated with any of the pQCT-derived bone parameters. Conclusions: Current pediatric TS patients that are treated with growth hormone and estrogens are not at risk for osteoporotic fractures. Low BMD in TS may be counterweighted by enlarged bone radius, which leads to normal bone strength at the appendicular skeleton.

Muscle functions and bone strength are impaired in adolescents with type 1 diabetes.

BACKGROUND: Sarcopenia and osteoporosis are among the late complications of type 1 diabetes (T1D) in adults. Whether and to what extent musculoskeletal impairment is present in childhood and adolescence has yet to be determined. The aim of this study was to assess volumetric bone mineral density (BMD) and dynamic muscle function in adolescents with T1D and to assess the clinical and biochemical predictors of their musculoskeletal system. METHODS: Ninety-five children and adolescents (59 boys and 36 girls, mean age 16.2±1.2years) with T1D were included in this cross-sectional study. Study participants were divided into two groups according to the duration of the disease (<6years and >9years, respectively). Volumetric BMD of the non-dominant tibia was assessed using peripheral quantitative computed tomography (pQCT). Dynamic muscle function was evaluated using jumping mechanography. Gender- and height-specific Z-scores were calculated using published reference data. HbA1c was evaluated retrospectively as an average over the past 5years. RESULTS: Relative muscle power (Pmax/mass) and force (Fmax/body weight) were significantly decreased in T1D subjects (mean Z-scores -0.4±1.0; p<0.001, and -0.3±1.1; p<0.01, respectively). The duration of T1D negatively affected Pmax/mass (p<0.01) but not Fmax/body weight (p=0.54). Patients with T1D had also decreased trabecular BMD, the Strength-Strain Index and cortical thickness (mean Z-scores -0.8±1.3; -0.5±0.8 and -1.1±0.8, respectively, p<0.001 for all) whereas cortical BMD was increased when compared to controls (Z-score 1.2±0.90, p<0.001). No association was observed between the HbA1c and 25-hydroxyvitamin D levels and bone or muscle parameters. CONCLUSION: T1D influences the musculoskeletal system in adolescence. Decreased muscle function could contribute to the osteoporosis reported in adult diabetic patients.

Dynamic balance in children with attention-deficit hyperactivity disorder and its relationship with cognitive functions and cerebellum.

BACKGROUND: Attention-deficit hyperactivity disorder (ADHD) is linked to the presence of motor deficiencies, including balance deficits. The cerebellum serves as an integrative structure for balance control and is also involved in cognition, including timing and anticipatory regulation. Cerebellar development may be delayed in children and adolescents with ADHD, and inconsistent reaction time is commonly seen in ADHD. We hypothesized that dynamic balance deficits would be present in children with ADHD and they would correlate with attention and cerebellar functions. METHODS: Sixty-two children with ADHD and no other neurological conditions and 62 typically developing (TD) children were examined with five trials of the Phyaction Balance Board, an electronic balancing platform. Cerebellar clinical symptoms were evaluated using an international ataxia rating scale. Conners' Continuous Performance Test was used to evaluate patterns of reaction. RESULTS: Children with ADHD had poorer performance on balancing tasks, compared to TD children (P<0.001). They exhibited significantly greater sway amplitudes than TD children (P<0.001) in all of the five balancing trials. The effect size of the difference between the groups increased continuously from the first to the last trial. Balance score in both groups was related to the variation in the reaction time, including reaction time standard error (r =0.25; P=0.0409, respectively, r =0.31; P=0.0131) and Variability of Standard Error (r =0.28; P=0.0252, respectively, r =0.41; P<0.001). The burden of cerebellar symptoms was strongly related to balance performance in both groups (r =0.50, P<0.001; r =0.49, P=0.001). CONCLUSION: This study showed that ADHD may be associated with poor dynamic balance control. Furthermore, we showed that maintaining balance correlates with neuropsychological measures of consistency of reaction time. Balance deficits and impaired cognitive functioning could reflect a common cerebellar dysfunction in ADHD children.

Cerebellar Symptoms Are Associated With Omission Errors and Variability of Response Time in Children With ADHD.

OBJECTIVE: We examined the presence of cerebellar symptoms in ADHD and their association with behavioral markers of this disorder. METHOD: Sixty-two children with ADHD and 62 typically developing (TD) children were examined for cerebellar symptoms using the ataxia rating scale and tested using Conners' Continuous Performance Test. RESULTS: Children with ADHD had significantly more cerebellar symptoms compared with the TD children. Cerebellar symptom scores decreased with age in the ADHD group; in the TD group remained stable. In both groups, cerebellar symptoms were associated with parent-rated hyperactive/impulsive symptoms, variability of response time standard error (RT-SE) and increase of RT-SE as the test progresses. More variables were associated with cerebellar symptoms in the ADHD group including omission errors, overall RT-SE and its increase for prolonged interstimulus intervals. CONCLUSION: Our results highlight the importance of research into motor functions in children with ADHD and indicate a role for cerebellar impairment in this disorder.

Early stages of pediatric bipolar disorder: retrospective analysis of a Czech inpatient sample.

BACKGROUND: Approximately 30%-60% of adults diagnosed with bipolar disorder (BD) report onset between the ages 15 and 19 years; however, a correct diagnosis is often delayed by several years. Therefore, investigations of the early features of BD are important for adequately understanding the prodromal stages of the illness. METHODS: A complete review of the medical records of 46 children and adolescents who were hospitalized for BD at two psychiatric teaching centers in Prague, Czech Republic was performed. Frequency of BD in all inpatients, age of symptom onset, phenomenology of mood episodes, lifetime psychiatric comorbidity, differences between very-early-onset (<13 years of age) and early-onset patients (13-18 years), and differences between the offspring of parents with and without BD were analyzed. RESULTS: The sample represents 0.83% of the total number of inpatients (n=5,483) admitted during the study period at both centers. BD often started with depression (56%), followed by hypomania (24%) and mixed episodes (20%). The average age during the first mood episode was 14.9 years (14.6 years for depression and 15.6 years for hypomania). Seven children (15%) experienced their first mood episode before age 13 years (very early onset). Traumatic events, first-degree relatives with mood disorders, and attention deficit hyperactivity disorder were significantly more frequent in the very-early-onset group vs the early-onset group (13-18 years) (P≤0.05). The offspring of bipolar parents were significantly younger at the onset of the first mood episode (13.2 vs 15.4 years; P=0.02) and when experiencing the first mania compared to the offspring of non-BD parents (14.3 vs 15.9 years; P=0.03). Anxiety disorders, substance abuse, specific learning disabilities, and attention deficit hyperactivity disorder were the most frequent lifetime comorbid conditions. CONCLUSION: Clinicians must be aware of the potential for childhood BD onset in patients who suffer from recurrent depression, who have first-degree relatives with BD, and who have experienced severe psychosocial stressors.

The muscle-bone interaction in Turner syndrome.

OBJECTIVES: Turner syndrome (TS) is associated with an increased fracture rate due to reduced bone strength, which is mainly determined by skeletal muscle force. This study aimed to assess the muscle force-bone strength relationship in TS and to compare it with that of healthy controls. METHODS: This study included 39 girls with TS and 67 healthy control girls. Maximum muscle force (Fmax) was assessed through multiple one-legged hopping with jumping mechanography. Peripheral quantitative computerized tomography assessed the bone strength index at the tibial metaphysis (BSI 4) and the polar strength-strain index at the diaphysis (SSI polar 66). The effect of TS on the muscle-bone unit was tested using multiple linear regression. RESULTS: TS had no impact on Fmax (p=0.14); however, a negative effect on bone strength (p<0.001 for BSI 4 and p<0.01 for SSI polar 66) was observed compared with healthy controls. Bone strength was lower in the TS group (by 18%, p<0.01, for BSI 4 and by 7%, p=0.027, for SSI polar 66), even after correcting for Fmax. CONCLUSIONS: Similar muscle force induces lower bone strength in TS compared with healthy controls, which suggests altered bone-loading sensitivity in TS.

HIV-related stigma, social norms, and HIV testing in Soweto and Vulindlela, South Africa: National Institutes of Mental Health Project Accept (HPTN 043).

OBJECTIVE: HIV testing is necessary to curb the increasing epidemic. However, HIV-related stigma and perceptions of low likelihood of societal HIV testing may reduce testing rates. This study aimed to explore this association in South Africa, where HIV rates are extraordinarily high. METHODS: Data were taken from the Soweto and Vulindlela, South African sites of Project Accept, a multinational HIV prevention trial. Self-reported HIV testing, stigma, and social norms items were used to study the relationship between HIV testing, stigma, and perceptions about societal testing rates. The stigma items were broken into 3 factors: negative attitudes, negative perceptions about people living with HIV, and perceptions of fair treatment for people living with HIV (equity). RESULTS: Results from a univariate logistic regression suggest that history of HIV testing was associated with decreased negative attitudes about people living with HIV/AIDS, increased perceptions that people living with HIV/AIDS experience discrimination, and increased perceptions that people with HIV should be treated equitably. Results from a multivariate logistic regression confirm these effects and suggest that these differences vary according to sex and age. Compared with people who had never tested for HIV, those who had previously tested were more likely to believe that the majority of people have tested for HIV. CONCLUSIONS: Data suggest that interventions designed to increase HIV testing in South Africa should address stigma and perceptions of societal testing.

A comparison of HIV/AIDS-related stigma in four countries: negative attitudes and perceived acts of discrimination towards people living with HIV/AIDS.

HIV/AIDS-related stigma and discrimination have a substantial impact on people living with HIV/AIDS (PLHA). The objectives of this study were: (1) to determine the associations of two constructs of HIV/AIDS-related stigma and discrimination (negative attitudes towards PLHA and perceived acts of discrimination towards PLHA) with previous history of HIV testing, knowledge of antiretroviral therapies (ARVs) and communication regarding HIV/AIDS and (2) to compare these two constructs across the five research sites with respect to differing levels of HIV prevalence and ARV coverage, using data presented from the baseline survey of U.S. National Institute of Mental Health (NIMH) Project Accept, a four-country HIV prevention trial in Sub-Saharan Africa (Tanzania, Zimbabwe and South Africa) and northern Thailand. A household probability sample of 14,203 participants completed a survey including a scale measuring HIV/AIDS-related stigma and discrimination. Logistic regression models determined the associations between negative attitudes and perceived discrimination with individual history of HIV testing, knowledge of ARVs and communication regarding HIV/AIDS. Spearman's correlation coefficients determined the relationships between negative attitudes and perceived discrimination and HIV prevalence and ARV coverage at the site-level. Negative attitudes were related to never having tested for HIV, lacking knowledge of ARVs, and never having discussed HIV/AIDS. More negative attitudes were found in sites with the lowest HIV prevalence (i.e., Tanzania and Thailand) and more perceived discrimination against PLHA was found in sites with the lowest ARV coverage (i.e., Tanzania and Zimbabwe). Programs that promote widespread HIV testing and discussion of HIV/AIDS, as well as education regarding and universal access to ARVs, may reduce HIV/AIDS-related stigma and discrimination.