1,154 research outputs found

    Characterization of Spontaneous and Induced Puberty in Girls with Turner Syndrome

    Get PDF
    OBJECTIVE: To characterize puberty in girls with Turner syndrome (TS) and determine whether specific patient characteristics are associated with the timing of menarche. We also sought to compare spontaneous versus induced puberty in these patients. METHODS: Medical records of girls followed in our Pediatric Endocrine clinic for TS from 2007 to 2015 were reviewed. RESULTS: Fifty-three girls were included, of whom 10 (19%) achieved menarche spontaneously and 43 (81%) received hormone replacement therapy (HRT). Of girls receiving HRT, a younger age at estrogen initiation correlated with a longer time to menarche (P = .02), and a mosaic karyotype was associated with a shorter time to menarche (P = .02), whereas no relationship was seen for body mass index, estrogen regimen, or maternal age at menarche. Nineteen girls (44%) receiving HRT had bleeding on estrogen alone at a wide dose range and were more likely to be on transdermal than oral preparations (P = .01). Girls with spontaneous puberty achieved menarche at a younger age (P<.01) and were more likely to have mosaic TS (P = .02). CONCLUSION: Significant variability in the timing of menarche exists among girls with TS. However, age at pubertal induction and karyotype were significantly correlated with age at menarche in our patients. A wide range of estrogen doses is seen in girls who bleed prior to progesterone, suggesting extreme variability in estrogen sensitivity among patients with TS. Girls achieving spontaneous menarche are younger and more likely to have a mosaic karyotype than those with induced menarche. Large-scale prospective studies are needed to confirm these results

    A growing disconnection from nature is evident in cultural products

    Get PDF
    Human connection with nature is widely believed to be in decline, even though empirical evidence on the magnitude and temporal pattern of the change is scarce. Studying works of popular culture in English throughout the 20th century and later, we document a cultural shift away from nature, beginning in the 1950s. Since then, references to nature have been decreasing steadily in fiction, song lyrics, and film storylines. No parallel decline is observed in references to the human-made environment. These findings are cause for concern, not only because they imply foregone benefits from engagement with nature, but also because cultural products are agents of socialization that can evoke curiosity, respect, and concern for the natural world

    Fowler-Nordheim-like local injection of photoelectrons from a silicon tip

    Full text link
    Tunneling between a photo-excited p-type silicon tip and a gold surface is studied as a function of tip bias, tip/sample distance and light intensity. In order to extend the range of application of future spin injection experiments, the measurements are carried out under nitrogen gas at room temperature. It is found that while tunneling of valence band electrons is described by a standard process between the semiconductor valence band and the metal, the tunneling of photoelectrons obeys a Fowler-Nordheim-like process directly from the conduction band. In the latter case, the bias dependence of the photocurrent as a function of distance is in agreement with theoretical predictions which include image charge effects. Quantitative analysis of the bias dependence of the dark and photocurrent spectra gives reasonable values for the distance, and for the tip and metal work functions. For small distances image charge effects induce a vanishing of the barrier and the bias dependence of the photocurrent is exponential. In common with many works on field emission, fluctuations in the tunneling currents are observed. These are mainly attributed to changes in the prefactor for the tunneling photocurrent, which we suggest is caused by an electric-field-induced modification of the thickness of the natural oxide layer covering the tip apex.Comment: 12 pages, 11 figures. Submitted to Phys. Rev.

    Characterizing and prognosticating chronic lymphocytic leukemia in the elderly: prospective evaluation on 455 patients treated in the United States.

    Get PDF
    BACKGROUND: Median age at diagnosis of patients with chronic lymphocytic leukemia (CLL) is \u3e 70 years. However, the majority of clinical trials do not reflect the demographics of CLL patients treated in the community. We examined treatment patterns, outcomes, and disease-related mortality in patients ≥ 75 years with CLL (E-CLL) in a real-world setting. METHODS: The Connect® CLL registry is a multicenter, prospective observational cohort study, which enrolled 1494 adult patients between 2010-2014, at 199 US sites. Patients with CLL were enrolled within 2 months of initiating first line of therapy (LOT1) or a subsequent LOT (LOT ≥ 2). Kaplan-Meier methods were used to evaluate overall survival. CLL- and infection-related mortality were assessed using cumulative incidence functions (CIF) and cause-specific hazards. Logistic regression was used to develop a classification model. RESULTS: A total of 455 E-CLL patients were enrolled; 259 were enrolled in LOT1 and 196 in LOT ≥ 2. E-CLL patients were more likely to receive rituximab monotherapy (19.3 vs. 8.6%; p \u3c 0.0001) and chemotherapy-alone regimens (p \u3c 0.0001) than younger patients. Overall and complete responses were lower in E-CLL patients than younger patients when given similar regimens. With a median follow-up of 3 years, CLL-related deaths were higher in E-CLL patients than younger patients in LOT1 (12.6 vs. 5.1% p = 0.0005) and LOT ≥ 2 (31.3 vs. 21.5%; p = 0.0277). Infection-related deaths were also higher in E-CLL patients than younger patients in LOT1 (7.4 vs. 2.7%; p = 0.0033) and in LOT ≥ 2 (16.2 vs. 11.2%; p = 0.0786). A prognostic score for E-CLL patients was developed: time from diagnosis to treatment \u3c 3 months, enrollment therapy other than bendamustine/rituximab, and anemia, identified patients at higher risk of inferior survival. Furthermore, higher-risk patients experienced an increased risk of CLL- or infection-related death (30.6 vs 10.3%; p = 0.0006). CONCLUSION: CLL- and infection-related mortality are higher in CLL patients aged ≥ 75 years than younger patients, underscoring the urgent need for alternative treatment strategies for these understudied patients. TRIAL REGISTRATION: The Connect CLL registry was registered at clinicaltrials.gov: NCT01081015 on March 4, 2010

    Toward integrated conservation of North America's crop wild relatives

    Get PDF
    North America harbors a rich native flora of crop wild relatives—the progenitors and closely related species of domesticated plants—as well as a range of culturally significant wild utilized plants. Despite their current and potential future value, they are rarely prioritized for conservation efforts; thus many species are threatened in their natural habitats, and most are underrepresented in plant genebanks and botanical gardens. Further coordination of efforts among land management, botanical, and agricultural science organizations will improve conservation and general public awareness with regard to these species. We present examples of productive collaborations focused on wild cranberries (Vaccinium macrocarpon and Vaccinium oxycoccos) and chile peppers (Capsicum annuum var. glabriusculum). We then discuss five shared priorities for further action: (1) understand and document North America's crop wild relatives and wild utilized plants, (2) protect threatened species in their natural habitats, (3) collect and conserve ex situ the diversity of prioritized species, (4) make this diversity accessible and attractive for plant breeding, research, and education, and (5) raise public awareness of their value and the threats to their persistence

    Vibration analysis of adding contaminants particles and carbon nanotubes to lithium grease of ball bearing

    Get PDF
    This paper examines vibration behavior of ball bearings dispersed by solid as a function of contamination of lubricant. Experimental tests were performed using SKF 6004 deep groove ball bearing, dispersed with different contaminants particles. Silica sand with different particle sizes, copper (Cu micro particles), poly methyl methacrylate (PMMA), low-density polyethylene (LDPE), and polyamide (PA), all at five concentration levels were used to disperse the lubricant. The contaminants concentration as well as the carbon nanotubes (CNTs) concentration is varied as 1, 2, 3, 4, and 5 wt. %. It was found that as the contaminants particles size and concentration increased, the corresponding acceleration values also increased up to certain limit. Furthermore, the vibration amplitudes decrease due to the increase of the copper concentration. The vibration amplitude was improved due to increase of concentration of carbon nanotubes CNTs

    Differential effects of hydrocortisone, prednisone, and dexamethasone on hormonal and pharmacokinetic profiles: a pilot study in children with congenital adrenal hyperplasia

    Get PDF
    BACKGROUND: Little is known about the comparative effects of different glucocorticoids on the adrenal and growth hormone (GH) axes in children with congenital adrenal hyperplasia (CAH). We sought to compare the effects of hydrocortisone (HC), prednisone (PDN), and dexamethasone (DEX) in children with classic CAH and to investigate a potential role of pharmacogenetics. METHODS: Subjects were randomly assigned to three sequential 6-week courses of HC, PDN, and DEX, each followed by evaluation of adrenal hormones, IGF-1, GH, and body mass index (BMI). Single nucleotide polymorphism (SNP) analysis of genes in the glucocorticoid pathway was also performed. RESULTS: Nine prepubertal subjects aged 8.1 ± 2.3 years completed the study. Mean ACTH, androstenedione, and 17-hydroxyprogesterone (17-OHP) values were lower following the DEX arm of the study than after subjects received HC (p ≤ 0.016) or PDN (p ≤ 0.002). 17-OHP was also lower after HC than PDN (p < 0.001). There was no difference in IGF-1, GH, or change in BMI. SNP analysis revealed significant associations between hormone concentrations, pharmacokinetic parameters, and variants in several glucocorticoid pathway genes (ABCB1, NR3C1, IP013, GLCCI1). CONCLUSIONS: DEX resulted in marked adrenal suppression suggesting that its potency relative to hydrocortisone and prednisone was underestimated. SNPs conferred significant differences in responses between subjects. Although preliminary, these pilot data suggest that incorporating pharmacogenetics has the potential to eventually lead to targeted therapy in children with CAH

    Real-world clinical experience in the Connect® chronic lymphocytic leukaemia registry: a prospective cohort study of 1494 patients across 199 US centres.

    Get PDF
    The clinical course of chronic lymphocytic leukaemia (CLL) is heterogeneous, and treatment options vary considerably. The Connect® CLL registry is a multicentre, prospective observational cohort study that provides a real-world perspective on the management of, and outcomes for, patients with CLL. Between 2010 and 2014, 1494 patients with CLL and that initiated therapy, were enrolled from 199 centres throughout the USA (179 community-, 17 academic-, and 3 government-based centres). Patients were grouped by line of therapy at enrolment (LOT). We describe the clinical and demographic characteristics of, and practice patterns for, patients with CLL enrolled in this treatment registry, providing patient-level observational data that represent real-world experiences in the USA. Fluorescence in&nbsp;situ hybridization (FISH) analyses were performed on 49·3% of patients at enrolment. The most common genetic abnormalities detected by FISH were del(13q) and trisomy 12 (45·7% and 20·8%, respectively). Differences in disease characteristics and comorbidities were observed between patients enrolled in LOT1 and combined LOT2/≥3 cohorts. Important trends observed include the infrequent use of genetic prognostic testing, and differences in patient characteristics for patients receiving chemoimmunotherapy combinations. These data represent experiences of patients with CLL in the USA, which may inform treatment decisions in everyday practice

    Foodways in transition: food plants, diet and local perceptions of change in a Costa Rican Ngäbe community

    Get PDF
    Background Indigenous populations are undergoing rapid ethnobiological, nutritional and socioeconomic transitions while being increasingly integrated into modernizing societies. To better understand the dynamics of these transitions, this article aims to characterize the cultural domain of food plants and analyze its relation with current day diets, and the local perceptions of changes given amongst the Ngäbe people of Southern Conte-Burica, Costa Rica, as production of food plants by its residents is hypothesized to be drastically in recession with an decreased local production in the area and new conservation and development paradigms being implemented. Methods Extensive freelisting, interviews and workshops were used to collect the data from 72 participants on their knowledge of food plants, their current dietary practices and their perceptions of change in local foodways, while cultural domain analysis, descriptive statistical analyses and development of fundamental explanatory themes were employed to analyze the data. Results Results show a food plants domain composed of 140 species, of which 85 % grow in the area, with a medium level of cultural consensus, and some age-based variation. Although many plants still grow in the area, in many key species a decrease on local production–even abandonment–was found, with much reduced cultivation areas. Yet, the domain appears to be largely theoretical, with little evidence of use; and the diet today is predominantly dependent on foods bought from the store (more than 50 % of basic ingredients), many of which were not salient or not even recognized as ‘food plants’ in freelists exercises. While changes in the importance of food plants were largely deemed a result of changes in cultural preferences for store bought processed food stuffs and changing values associated with farming and being food self-sufficient, Ngäbe were also aware of how changing household livelihood activities, and the subsequent loss of knowledge and use of food plants, were in fact being driven by changes in social and political policies, despite increases in forest cover and biodiversity. Conclusions Ngäbe foodways are changing in different and somewhat disconnected ways: knowledge of food plants is varied, reflecting most relevant changes in dietary practices such as lower cultivation areas and greater dependence on food from stores by all families. We attribute dietary shifts to socioeconomic and political changes in recent decades, in particular to a reduction of local production of food, new economic structures and agents related to the State and globalization

    Effect of Biodiversity Changes in Disease Risk: Exploring Disease Emergence in a Plant-Virus System

    Get PDF
    The effect of biodiversity on the ability of parasites to infect their host and cause disease (i.e. disease risk) is a major question in pathology, which is central to understand the emergence of infectious diseases, and to develop strategies for their management. Two hypotheses, which can be considered as extremes of a continuum, relate biodiversity to disease risk: One states that biodiversity is positively correlated with disease risk (Amplification Effect), and the second predicts a negative correlation between biodiversity and disease risk (Dilution Effect). Which of them applies better to different host-parasite systems is still a source of debate, due to limited experimental or empirical data. This is especially the case for viral diseases of plants. To address this subject, we have monitored for three years the prevalence of several viruses, and virus-associated symptoms, in populations of wild pepper (chiltepin) under different levels of human management. For each population, we also measured the habitat species diversity, host plant genetic diversity and host plant density. Results indicate that disease and infection risk increased with the level of human management, which was associated with decreased species diversity and host genetic diversity, and with increased host plant density. Importantly, species diversity of the habitat was the primary predictor of disease risk for wild chiltepin populations. This changed in managed populations where host genetic diversity was the primary predictor. Host density was generally a poorer predictor of disease and infection risk. These results support the dilution effect hypothesis, and underline the relevance of different ecological factors in determining disease/infection risk in host plant populations under different levels of anthropic influence. These results are relevant for managing plant diseases and for establishing conservation policies for endangered plant species
    corecore