160 research outputs found

    Reduced metal transferrin binding in neurological diseases

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    By employing G75 gel-filtration chromotography, it has been demonstrated that human plasma gallium speciation (and by implication, Al speciation) is bimodal. Normally, gallium was predominantly bound to a high molecular weight fraction which was presumably transferrin. Literature reviews and experimental work throughout this thesis provided evidence to support this idea. An aluminium-transferrin species was assumed to be relatively non-toxic and a protective function for this complex has been suggested. A second, low molecular weight species of gallium was observed and its identity has been suggested to be citrate. The results of this thesis support the concept citrate was a gallium binding ligand present in the plasma, but there was another species (tentatively identified as phosphate) which bound gallium to a much greater degree than did citrate in the majority of samples studied. The consequence of a low molecular weight species of aluminium is the possibility that this leads to a more rapid, uncontrolled deposition of the metal in the brain compared to a transferrin mediated mechanism. Plasma speciation studies in Alzheimer's disease, Parkinson's disease, Down's syndrome, and neonates has revealed an altered ratio of the two gallium species found in control subjects. In all groups there was an increase in the potentially more neurotoxic low molecular weight species. These observations have led to a suggested mechanism of accumulation of metals in the brain, which is known to occur in the first three groups. Possible pathogenic mechanisms are described. The results can also offer an explanation to the reported increased sensitivity to the toxic effects of aluminium in the neonate. Speciation studies on normal plasma has shown the balance between high and low molecular weight species of gallium to be influenced by many physiological factors. There appears to be a fine equilibrium between both species which can be altered without any great difficulty. Therefore, in the diseased groups studied, it is possible that there are subtle biochemical changes within the circulatory system to affect the equilibrium which results in an increased low molecular weight species of aluminium. Furthermore, it has been demonstrated that there is a group of normal controls with no clinical signs of Alzheimer's or Parkinson's disease which have reduced transferrin binding. This indicates there is a population of healthy people who are at risk to the development of either disease

    Reference hydrologic networks II: using reference hydrologic networks to assess climate-driven changes in streamflow

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    Reference hydrologic networks (RHNs) can play an important role in monitoring for changes in the hydrological regime related to climate variation and change. Currently, the literature concerning hydrological response to climate variations is complex and confounded by the combinations of many methods of analysis, wide variations in hydrology, and the inclusion of data series that include changes in land use, storage regulation and water use in addition to those of climate. Three case studies that illustrate a variety of approaches to the analysis of data from RHNs are presented and used, together with a summary of studies from the literature, to develop approaches for the investigation of changes in the hydrological regime at a continental or global scale, particularly for international comparison. We present recommendations for an analysis framework and the next steps to advance such an initiative. There is a particular focus on the desirability of establishing standardized procedures and methodologies for both the creation of new national RHNs and the systematic analysis of data derived from a collection of RHNs

    The decisions regarding ADHD management (DRAMa) study: uncertainties and complexities in assessment, diagnosis and treatment, from the clinician's point of view

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    Clinical decision making is influenced by a range of factors and constitutes an inherently complex task. Here we present results from the decisions regarding ADHD management (DRAMa) study in which we undertook a thematic analysis of clinicians' experiences and attitudes to assessment, diagnosis and treatment of ADHD. Fifty prescribing child psychiatrists and paediatricians from Belgium and the UK took part in semi-structured interviews about their decisions regarding the assessment, diagnosis and treatment of ADHD. Interviews were transcribed and processed using thematic analysis and the principles of grounded theory. Clinicians described the assessment and diagnostic process as inherently complicated and requiring time and experience to piece together the accounts of children made by multiple sources and through the use of varying information gathering techniques. Treatment decisions were viewed as a shared process between families, children, and the clinician. Published guidelines were viewed as vague, and few clinicians spoke about the use of symptom thresholds or specific impairment criteria. Furthermore, systematic or operationalised criteria to assess treatment outcomes were rarely used. Decision making in ADHD is regarded as a complicated, time consuming process which requires extensive use of clinical impression, and involves a partnership with parents. Clinicians want to separate biological from environmental causal factors to understand the level of impairment and the subsequent need for a diagnosis of ADHD. Clinical guidelines would benefit from revisions to take into account the real-world complexities of clinical decision making for ADHD

    Reference hydrologic networks I: the status and potential future directions of national reference hydrologic networks for detecting trends

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    Identifying climate-driven trends in river flows on a global basis is hampered by a lack of long, quality time series data for rivers with relatively undisturbed regimes. This is a global problem compounded by the lack of support for essential long-term monitoring. Experience demonstrates that, with clear strategic objectives, and the support of sponsoring organizations, reference hydrologic networks can constitute an exceptionally valuable data source to effectively identify, quantify and interpret hydrological change—the speed and magnitude of which is expected to a be a primary driver of water management and flood alleviation strategies through the future—and for additional applications. Reference hydrologic networks have been developed in many countries in the past few decades. These collections of streamflow gauging stations, that are maintained and operated with the intention of observing how the hydrology of watersheds responds to variations in climate, are described. The status of networks under development is summarized. We suggest a plan of actions to make more effective use of this collection of networks

    Impact of Mental Health Comorbidities on Health Care Utilization and Expenditure in a Large US Managed Care Adult Population with ADHD

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    AbstractObjectiveTo estimate the health resource use (HRU) and expenditure of adult patients with attention deficit/hyperactivity disorder (ADHD) subsequently diagnosed with one or more mental health (MH) comorbidities.MethodsUsing Kaiser Permanente Southern California electronic medical records (January 1, 2006, to December 31, 2009), we identified adults with at least one ADHD diagnosis and at least two subsequent prescriptions fills for ADHD medication. The date of first MH comorbidity diagnosis after the index ADHD diagnosis was defined as the index transition date. Continuous eligibility 12 months before and after the index transition date was required. For patients with multiple transitions (≥2), the post-transition period reflected the 12 months after the second transition. HRU for all-cause inpatient, outpatient, emergency department, behavioral therapy, overall prescription fill counts, and ADHD-specific prescription fill counts and mean patient expenditure (2010 US )wereestimated.GeneralizedestimatingequationswereusedtoevaluatedifferencesinHRUandexpenditurebetweenthepreandposttransitionperiods,respectively.ResultsOfthe3809patientswithADHDidentified,989(26) were estimated. Generalized estimating equations were used to evaluate differences in HRU and expenditure between the pre- and post-transition periods, respectively.ResultsOf the 3809 patients with ADHD identified, 989 (26%) had at least one transition (n = 357 single and n = 632 multiple). From the pre- to the post-transition period, for single transition cohort, all HRU increased significantly except for behavioral therapy. In the multiple transition cohort, all HRU increased significantly. Total expenditure increased by mean ± SE of 1822 ± 306and306 and 4432 ± $301 (both P < 0.0001) in the single and multiple transition cohorts, respectively.ConclusionsTwenty-six percent of patients with ADHD transitioned to MH comorbid diagnoses. Increased HRU and expenditure were associated with MH transitions. Identifying of patients with ADHD at risk for MH comorbidities may help to improve their outcomes

    Treatment response and remission in a double-blind, randomized, head-to-head study of lisdexamfetamine dimesylate and atomoxetine in children and adolescents with attention-deficit hyperactivity disorder

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    The Author(s) 2014. This article is published with open access at Springerlink.com Objectives A secondary objective of this head-to-head study of lisdexamfetamine dimesylate (LDX) and ato-moxetine (ATX) was to assess treatment response rates in children and adolescents with attention-deficit hyperactiv-ity disorder (ADHD) and an inadequate response to methylphenidate (MPH). The primary efficacy and safety outcomes of the study, SPD489-317 (ClinicalTrials.gov NCT01106430), have been published previously. Methods In this 9-week, double-blind, active-controlled study, patients aged 6–17 years with a previous inadequate response to MPH were randomized (1:1) to dose-optimized LDX (30, 50 or 70 mg/day) or ATX (patients \70 kg: 0.5–1.2 mg/kg/day, not to exceed 1.4 mg/kg/day; patients C70 kg: 40, 80 or 100 mg/day). Treatment response was a secondary efficacy outcome and was predefined as a reduction from baseline in ADHD Rating Scale IV (ADHD-RS-IV) total score of at least 25, 30 or 50 %. Sustained response was predefined as a reduction from baseline in ADHD-RS-IV total score (C25, C30 or C50 %) or a Clinical Global Impressions (CGI)–Improvement (CGI–I) score of 1 or 2 throughout weeks 4–9. CGI– Severity (CGI–S) scores were also assessed, as an indicator of remission. Results A total of 267 patients were enrolled (LDX, n = 133; ATX, n = 134) and 200 completed the study (LDX, n = 99; ATX, n = 101). By week 9, significantly (p \ 0.01) greater proportions of patients receiving LDX than ATX met the response criteria of a reduction from baseline in ADHD-RS-IV total score of at least 25 % (90.5 vs. 76.7 %), 30 % (88.1 vs. 73.7 %) or 50 % (73.0 vs. 50.4 %). Sustained response rates were also signifi-cantly (p \ 0.05) higher among LDX-treated patient

    Economic impact of childhood/adolescent ADHD in a European setting:the Netherlands as a reference case

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    Attention-deficit/hyperactivity disorder (ADHD) is a highly prevalent psychiatric disorder in children/adolescents. This study reviews available European-based studies of ADHD-related costs and applies the findings to the Netherlands to estimate annual national costs for children/adolescents from a societal perspective. A systematic literature search was conducted for primary studies in Europe, published January 1, 1990 through April 23, 2013. Per-person cost estimates were converted to 2012 Euros and used to estimate annual national ADHD-related costs based on the Dutch 2011 census, ADHD prevalence rates, family composition, and employment rates. Seven studies met the inclusion criteria. The average total ADHD-related costs ranged from a,not sign9,860 to a,not sign14,483 per patient and annual national costs were between a,not sign1,041 and a,not sign1,529 million (M). The largest cost category was education (a,not sign648 M), representing 62 and 42 % of the low- and high-value overall national estimates, respectively. By comparison, ADHD patient healthcare costs ranged between a,not sign84 M (8 %) and a,not sign377 M (25 %), and social services costs were a,not sign4.3 M (0.3-0.4 %). While the majority of the costs were incurred by ADHD patients themselves, a,not sign161 M (11-15 %) was healthcare costs to family members that were attributable to having an ADHD child/adolescent. In addition, productivity losses of family members were a,not sign143-a,not sign339 M (14-22 %). Despite uncertainties because of the small number of studies identified and the wide range in the national cost estimates, our results suggest that ADHD imposes a significant economic burden on multiple public sectors in Europe. The limited number of European-based studies examining the economic burden of ADHD highlights the need for more research in this area

    The 'dirty dozen' of freshwater science: detecting then reconciling hydrological data biases and errors

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    Sound water policy and management rests on sound hydrometeorological and ecological data. Conversely, unrepresentative, poorly collected, or erroneously archived data introduce uncertainty regarding the magnitude, rate, and direction of environmental change, in addition to undermining confidence in decision-making processes. Unfortunately, data biases and errors can enter the information flow at various stages, starting with site selection, instrumentation, sampling/measurement procedures, postprocessing and ending with archiving systems. Techniques such as visual inspection of raw data, graphical representation, and comparison between sites, outlier, and trend detection, and referral to metadata can all help uncover spurious data. Tell-tale signs of ambiguous and/or anomalous data are highlighted using 12 carefully chosen cases drawn mainly from hydrology (‘the dirty dozen’). These include evidence of changes in site or local conditions (due to land management, river regulation, or urbanization); modifications to instrumentation or inconsistent observer behavior; mismatched or misrepresentative sampling in space and time; treatment of missing values, postprocessing and data storage errors. Also for raising awareness of pitfalls, recommendations are provided for uncovering lapses in data quality after the information has been gathered. It is noted that error detection and attribution are more problematic for very large data sets, where observation networks are automated, or when various information sources have been combined. In these cases, more holistic indicators of data integrity are needed that reflect the overall information life-cycle and application(s) of the hydrological data

    The “dirty dozen” of freshwater science: Detecting then reconciling hydrological data biases and errors

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    Sound water policy and management rests on sound hydrometeorological and ecological data. Conversely, unrepresentative, poorly collected or erroneously archived data introduces uncertainty regarding the magnitude, rate and direction of environmental change, in addition to undermining confidence in decision-making processes. Unfortunately, data biases and errors can enter the information flow at various stages, starting with site selection, instrumentation, sampling/ measurement procedures, post-processing and ending with archiving systems. Techniques such as visual inspection of raw data, graphical representation and comparison between sites, outlier and trend detection, and referral to metadata can all help uncover spurious data. Tell-tale signs of ambiguous and/or anomalous data are highlighted using 12 carefully chosen cases drawn mainly from hydrology (‘the dirty dozen’). These include evidence of changes in site or local conditions (due to land management, river regulation or urbanisation); modifications to instrumentation or inconsistent observer behaviour; mismatched or misrepresentative sampling in space and time; treatment of missing values, post-processing and data storage errors. As well as raising awareness of pitfalls, recommendations are provided for uncovering lapses in data quality after the information has been gathered. It is noted that error detection and attribution are more problematic for very large data sets, where observation networks are automated, or when various information sources have been combined. In these cases, more holistic indicators of data integrity are needed that reflect the overall information life-cycle and application(s) of the hydrological data
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