2,712 research outputs found

    The relationship between anti-mullerian hormone in women receiving fertility assessments and age at menopause in subfertile women: evidence from large population studies

    Get PDF
    <p>Context: Anti-Müllerian hormone (AMH) concentration reflects ovarian aging and is argued to be a useful predictor of age at menopause (AMP). It is hypothesized that AMH falling below a critical threshold corresponds to follicle depletion, which results in menopause. With this threshold, theoretical predictions of AMP can be made. Comparisons of such predictions with observed AMP from population studies support the role for AMH as a forecaster of menopause.</p> <p>Objective: The objective of the study was to investigate whether previous relationships between AMH and AMP are valid using a much larger data set.</p> <p>Setting: AMH was measured in 27 563 women attending fertility clinics.</p> <p>Study Design: From these data a model of age-related AMH change was constructed using a robust regression analysis. Data on AMP from subfertile women were obtained from the population-based Prospect-European Prospective Investigation into Cancer and Nutrition (Prospect-EPIC) cohort (n = 2249). By constructing a probability distribution of age at which AMH falls below a critical threshold and fitting this to Prospect-EPIC menopausal age data using maximum likelihood, such a threshold was estimated.</p> <p>Main Outcome: The main outcome was conformity between observed and predicted AMP.</p> <p>Results: To get a distribution of AMH-predicted AMP that fit the Prospect-EPIC data, we found the critical AMH threshold should vary among women in such a way that women with low age-specific AMH would have lower thresholds, whereas women with high age-specific AMH would have higher thresholds (mean 0.075 ng/mL; interquartile range 0.038–0.15 ng/mL). Such a varying AMH threshold for menopause is a novel and biologically plausible finding. AMH became undetectable (<0.2 ng/mL) approximately 5 years before the occurrence of menopause, in line with a previous report.</p> <p>Conclusions: The conformity of the observed and predicted distributions of AMP supports the hypothesis that declining population averages of AMH are associated with menopause, making AMH an excellent candidate biomarker for AMP prediction. Further research will help establish the accuracy of AMH levels to predict AMP within individuals.</p&gt

    Assessment of ovarian reserve: Anti-Mullerian hormone versus follicle stimulating hormone

    Get PDF
    Background: This study aimed to evaluate the strength of anti-Mullerian hormone (AMH) and follicle stimulating hormone (FSH) in reflecting the antral follicle count (AFC) in infertile females.Materials and methods: This cross-sectional study was conducted on 160 females, visiting infertility clinic for assisted reproduction. Serum samples collected on the 3rd day of the cycle were assayed for FSH, luteinizing hormone, and AMH while AFC was assessed via transvaginal ultrasound. The study cohort was segregated into three groups based on AFC.Results: Chronological age and FSH was significantly high in females with very low AFC (P \u3c 0.01 and 0.009, respectively), yet they failed to discriminate patients with normal and higher follicle count (P = 0.65 and 0.84). Conversely, AMH reported highly significant difference between very low AFC and with those having either normal AFC (P = 0.002) or higher AFC (P = 0.001). Moreover, a significant difference in AMH was observed between normal and higher AFC group (P = 0.04).Conclusion: Compared to female\u27s age and FSH, AMH is superior in clustering study cohort on the bases of antral follicular pool, especially in setups with nonavailability of technological expertise to assess AFC. Incorporation of AMH along with other biomarkers improves estimation of baseline ovarian reserve, required to standardize dose for optimum response; avoiding the risk of failure to retrieve oocyte or inappropriate stimulation leading to ovarian hyperstimulation syndrome. Further prospective studies are required to ascertain its role in predicting the outcomes of ART in such patients

    Temporally delayed linear modelling (TDLM) measures replay in both animals and humans

    Get PDF
    There are rich structures in off-task neural activity which are hypothesised to reflect fundamental computations across a broad spectrum of cognitive functions. Here, we develop an analysis toolkit - Temporal Delayed Linear Modelling (TDLM) for analysing such activity. TDLM is a domain-general method for finding neural sequences that respect a pre-specified transition graph. It combines nonlinear classification and linear temporal modelling to test for statistical regularities in sequences of task-related reactivations. TDLM is developed on the non-invasive neuroimaging data and is designed to take care of confounds and maximize sequence detection ability. Notably, as a linear framework, TDLM can be easily extended, without loss of generality, to capture rodent replay in electrophysiology, including in continuous spaces, as well as addressing second-order inference questions, e.g., its temporal and spatial varying pattern. We hope TDLM will advance a deeper understanding of neural computation and promote a richer convergence between animal and human neuroscience

    Plastic energies in layered superconductors

    Full text link
    We estimate the energy cost associated with two pancake vortices colliding in a layered superconductor. It is argued that this energy sets the plastics energy scale and is the analogue of the crossing energy for vortices in the continuum case. The starting point of the calculation is the Lawrence-Doniach version of the Ginzburg-Landau free energy for type-II superconductors. The magnetic fields considered are along the c-direction and assumed to be sufficiently high that the lowest Landau level approximation is valid. For Bi-2212, where it is know that layering is very important, the results are radically different from what would have been obtained using a three-dimensional anisotropic continuum model. We then use the plastic energy for Bi-2212 to successfully explain recent results from Hellerqvist {\em et al.}\ on its longitudinal resistance.Comment: 5 Pages Revtex, 4 uuencoded postscript figure

    Incidence, risk factors and causes of death in an HIV care programme with a large proportion of injecting drug users.

    Get PDF
    Objectives  To identify factors influencing mortality in an HIV programme providing care to large numbers of injecting drug users (IDUs) and patients co-infected with hepatitis C (HCV). Methods  A longitudinal analysis of monitoring data from HIV-infected adults who started antiretroviral therapy (ART) between 2003 and 2009 was performed. Mortality and programme attrition rates within 2 years of ART initiation were estimated. Associations with individual-level factors were assessed with multivariable Cox and piece-wise Cox regression. Results  A total of 1671 person-years of follow-up from 1014 individuals was analysed. Thirty-four percent of patients were women and 33% were current or ex-IDUs. 36.2% of patients (90.8% of IDUs) were co-infected with HCV. Two-year all-cause mortality rate was 5.4 per 100 person-years (95% CI, 4.4-6.7). Most HIV-related deaths occurred within 6 months of ART start (36, 67.9%), but only 5 (25.0%) non-HIV-related deaths were recorded during this period. Mortality was higher in older patients (HR = 2.50; 95% CI, 1.42-4.40 for ≥40 compared to 15-29 years), and in those with initial BMI < 18.5 kg/m(2) (HR = 3.38; 95% CI, 1.82-5.32), poor adherence to treatment (HR = 5.13; 95% CI, 2.47-10.65 during the second year of therapy), or low initial CD4 cell count (HR = 4.55; 95% CI, 1.54-13.41 for <100 compared to ≥100 cells/μl). Risk of death was not associated with IDU status (P = 0.38). Conclusion  Increased mortality was associated with late presentation of patients. In this programme, death rates were similar regardless of injection drug exposure, supporting the notion that satisfactory treatment outcomes can be achieved when comprehensive care is provided to these patients

    Does landscape-scale conservation management enhance the provision of ecosystem services?

    Get PDF
    Biodiversity conservation approaches are increasingly being implemented at the landscape-scale to support the maintenance of metapopulations and metacommunities. However, the impact of such interventions on the provision of ecosystem services is less well defined. Here we examine the potential impacts of landscape-scale conservation initiatives on ecosystem services, through analysis of five case study areas in England and Wales. The provision of multiple ecosystem services was projected according to current management plans and compared with a baseline scenario. Multicriteria analysis indicated that in most cases landscape-scale approaches lead to an overall increase in service provision. Consistent increases were projected in carbon storage, recreation and aesthetic value, as well as biodiversity value. However, most study areas provided evidence of trade-offs, particularly between provisioning services and other types of service. Results differed markedly between study areas, highlighting the importance of local context. These results suggest that landscape-scale conservation approaches are likely to be effective in increasing ecosystem service provision, but also indicate that associated costs can be significant, particularly in lowland areas

    Renal impairment in a rural African antiretroviral programme

    Get PDF
    Background: There is little knowledge regarding the prevalence and nature of renal impairment in African populations initiating antiretroviral treatment, nor evidence to inform the most cost effective methods of screening for renal impairment. With the increasing availability of the potentially nephrotixic drug, tenofovir, such information is important for the planning of antiretroviral programmes Methods: (i) Retrospective review of the prevalence and risk factors for impaired renal function in 2189 individuals initiating antiretroviral treatment in a rural African setting between 2004 and 2007 (ii) A prospective study of 149 consecutive patients initiating antiretrovirals to assess the utility of urine analysis for the detection of impaired renal function. Severe renal and moderately impaired renal function were defined as an estimated GFR of ≤ 30 mls/min/1.73 m2 and 30–60 mls/min/1.73 m2 respectively. Logistic regression was used to determine odds ratio (OR) of significantly impaired renal function (combining severe and moderate impairment). Co-variates for analysis were age, sex and CD4 count at initiation. Results: (i) There was a low prevalence of severe renal impairment (29/2189, 1.3% 95% C.I. 0.8–1.8) whereas moderate renal impairment was more frequent (287/2189, 13.1% 95% C.I. 11.6–14.5) with many patients having advanced immunosuppression at treatment initiation (median CD4 120 cells/μl). In multivariable logistic regression age over 40 (aOR 4.65, 95% C.I. 3.54–6.1), male gender (aOR 1.89, 95% C.I. 1.39–2.56) and CD4<100 cells/ul (aOR 1.4, 95% C.I. 1.07–1.82) were associated with risk of significant renal impairment (ii) In 149 consecutive patients, urine analysis had poor sensitivity and specificity for detecting impaired renal function. Conclusion: In this rural African setting, significant renal impairment is uncommon in patients initiating antiretrovirals. Urine analysis alone may be inadequate for identification of those with impaired renal function where resources for biochemistry are limited

    Alteration of Hypothalamic–Pituitary–Thyroid Axis Function in Non-Small-Cell Lung Cancer Patients

    Get PDF
    The aim of this study was to evaluate the hypothalamic–pituitary–thyroid (HPT) axis function in patients suffering from lung cancer. Thyrotropin-releasing hormone (TRH), thyroid-stimulating hormone (TSH), free thyroxine (FT4), interleukin (IL)-2, and melatonin serum levels were measured in blood samples collected every 4 hours for 24 hours from 11 healthy participants (H; ages 35-53 years) and 9 patients suffering from non-small-cell lung cancer (C; ages 43-63 years). Relationships between hormone levels overall and over time of day were evaluated within and among groups. A prominent circadian rhythm with peaks near midnight was present for TSH and melatonin serum levels in both H and C, indicating similar synchronization of the main body clock to the 24-hour environmental light–dark cycle. As regards 24-hour means in H and C, TSH was lower in C, whereas TRH, FT4, and IL-2 were higher in C, with no difference in melatonin levels. Simple linear regression, FT4 versus TRH, showed a positive correlation in H..

    Genetic evidence for an essential role of neuronally expressed IL-6 signal transducer gp130 in the induction and maintenance of experimentally induced mechanical hypersensitivity in vivo and in vitro

    Get PDF
    Tenderness and mechanical allodynia are key symptoms of malignant tumor, inflammation and neuropathy. The proinflammatory cytokine interleukin-6 (IL-6) is causally involved in all three pathologies. IL-6 not only regulates innate immunity and inflammation but also causes nociceptor sensitization and hyperalgesia. In general and in most cell types including immune cells and sensory neurons, IL-6 binds soluble μ receptor subunits which heteromerizes with membrane bound IL-6 signal transducer gp130. In the present study, we used a conditional knock-out strategy to investigate the importance of signal transducer gp130 expressed in C nociceptors for the generation and maintenance of mechanical hypersensitivity. Nociceptors were sensitized to mechanical stimuli by experimental tumor and this nociceptor sensitization was preserved at later stages of the pathology in control mice. However, in mice with a conditional deletion of gp130 in Nav1.8 expressing nociceptors mechanical hypersensitivity by experimental tumor, nerve injury or inflammation recovery was not preserved in the maintenance phase and nociceptors exhibited normal mechanical thresholds comparable to untreated mice. Together, the results argue for IL-6 signal transducer gp130 as an essential prerequisite in nociceptors for long-term mechanical hypersensitivity associated with cancer, inflammation and nerve injury
    corecore