50 resultados para Optimal Control Problems
Resumo:
Reliable detection of JAK2-V617F is critical for accurate diagnosis of myeloproliferative neoplasms (MPNs); in addition, sensitive mutation-specific assays can be applied to monitor disease response. However, there has been no consistent approach to JAK2-V617F detection, with assays varying markedly in performance, affecting clinical utility. Therefore, we established a network of 12 laboratories from seven countries to systematically evaluate nine different DNA-based quantitative PCR (qPCR) assays, including those in widespread clinical use. Seven quality control rounds involving over 21,500 qPCR reactions were undertaken using centrally distributed cell line dilutions and plasmid controls. The two best-performing assays were tested on normal blood samples (n=100) to evaluate assay specificity, followed by analysis of serial samples from 28 patients transplanted for JAK2-V617F-positive disease. The most sensitive assay, which performed consistently across a range of qPCR platforms, predicted outcome following transplant, with the mutant allele detected a median of 22 weeks (range 6-85 weeks) before relapse. Four of seven patients achieved molecular remission following donor lymphocyte infusion, indicative of a graft vs MPN effect. This study has established a robust, reliable assay for sensitive JAK2-V617F detection, suitable for assessing response in clinical trials, predicting outcome and guiding management of patients undergoing allogeneic transplant.
Resumo:
BACKGROUND A number of epidemiological studies indicate an inverse association between atopy and brain tumors in adults, particularly gliomas. We investigated the association between atopic disorders and intracranial brain tumors in children and adolescents, using international collaborative CEFALO data. PATIENTS AND METHODS CEFALO is a population-based case-control study conducted in Denmark, Norway, Sweden, and Switzerland, including all children and adolescents in the age range 7-19 years diagnosed with a primary brain tumor between 2004 and 2008. Two controls per case were randomly selected from population registers matched on age, sex, and geographic region. Information about atopic conditions and potential confounders was collected through personal interviews. RESULTS In total, 352 cases (83%) and 646 controls (71%) participated in the study. For all brain tumors combined, there was no association between ever having had an atopic disorder and brain tumor risk [odds ratio 1.03; 95% confidence interval (CI) 0.70-1.34]. The OR was 0.76 (95% CI 0.53-1.11) for a current atopic condition (in the year before diagnosis) and 1.22 (95% CI 0.86-1.74) for an atopic condition in the past. Similar results were observed for glioma. CONCLUSIONS There was no association between atopic conditions and risk of all brain tumors combined or of glioma in particular. Stratification on current or past atopic conditions suggested the possibility of reverse causality, but may also the result of random variation because of small numbers in subgroups. In addition, an ongoing tumor treatment may affect the manifestation of atopic conditions, which could possibly affect recall when reporting about a history of atopic diseases. Only a few studies on atopic conditions and pediatric brain tumors are currently available, and the evidence is conflicting.
Resumo:
Purpose: Results from previous studies indicate that children with brain tumors (BT) might present with cognitive problems at diagnosis and thus before the start of any medical treatment. The question remains whether these problems are due to the underlying tumor itself or due to the high level of emotional and physical stress which is involved at diagnosis of a malignant disorder. All children with a de novo oncological diagnosis not involving the central nervous systems (CNS) are usually exposed to a comparable level of distress. However, patients with cancer not involving the CNS are not expected to show disease-related cognitive problems. Thus they serve as a well-balanced control group (CG) to help distinguish between the probable causes of the effect. Method: In a pilot study we analyzed an array of cognitive functions in 16 children with BT and 17 control patients. In both groups, tests were administered in-patient at diagnosis before any therapeutic intervention such as surgery, chemotherapy od irradiation. Results: Performance of children with BT was comparable to that of CG patients in the areas of intelligence, perceptual reasoning, verbal comprehension, working memory, and processing speed. In contrast, however, BT patients performded significantly worse in verbal memory and attention. Conclusion: Memory and attention seem to be the most vulnerable funstions affected by BT, with other functions being preserved at the time of diagnosis. It ist to be expected that this vulnerability might exacerbate the cognitive decline after chemotherapy and radiation treatment - known to impair intellectual performance. The findings highlight the need of early cognitive assessments in children with BT in order to introduce cognitive training as early as possible to minimize or even prevent cognitive long-term sequelae. This might improve long-term academic and professional outcome of these children, but especially helps their return to school after hospitalization.
Resumo:
Chlamydia trachomatis infection (chlamydia) is the most common notifiable bacterial sexually transmitted infection (STI) worldwide. In the United States of America (USA) in 2009, 1,244,180 cases of chlamydia were reported to the Centers for Disease Control and Prevention (CDC), the largest number of cases ever reported to CDC for any notifiable disease [1]. It has been estimated, from population prevalence surveys, that approximately 2 % of sexually active adults aged 18–44 years old in the UK [2] and 2.2 % (CI, 1.8–2.8 %) of the US population aged 14–39 years [3] are infected with chlamydia. This level of prevalence in the USA translates into an estimated 2,291,000 (95 % confidence interval, CI, 1,857,000–2,838,000) chlamydia infections each year [3]. Globally, the World Health Organization (WHO) estimates that there are about 92 million new cases of chlamydia each year [4].
Resumo:
An imminent food crisis reinforces the need for novel strategies to increase crop yields worldwide. Effective control of pest insects should be part of such strategies, preferentially with reduced negative impact on the environment and optimal protection and utilization of existing biodiversity. Enhancing the presence and efficacy of native biological control agents could be one such strategy. Plant strengthener is a generic term for several commercially available compounds or mixtures of compounds that can be applied to cultivated plants in order to ‘boost their vigour, resilience and performance’. Studies into the consequences of boosting plant resistance against pests and diseases on plant volatiles have found a surprising and dramatic increase in the plants' attractiveness to parasitic wasps. Here, we summarize the results from these studies and present new results from assays that illustrate the great potential of two commercially available resistance elicitors. We argue that plant strengtheners may currently be the best option to enhance the attractiveness of cultivated plants to biological control agents. Other options, such as the genetic manipulation of the release of specific volatiles may offer future solutions, but in most systems, we still miss fundamental knowledge on which key attractants should be targeted for this approach.
Resumo:
Historical information is always relevant for clinical trial design. Additionally, if incorporated in the analysis of a new trial, historical data allow to reduce the number of subjects. This decreases costs and trial duration, facilitates recruitment, and may be more ethical. Yet, under prior-data conflict, a too optimistic use of historical data may be inappropriate. We address this challenge by deriving a Bayesian meta-analytic-predictive prior from historical data, which is then combined with the new data. This prospective approach is equivalent to a meta-analytic-combined analysis of historical and new data if parameters are exchangeable across trials. The prospective Bayesian version requires a good approximation of the meta-analytic-predictive prior, which is not available analytically. We propose two- or three-component mixtures of standard priors, which allow for good approximations and, for the one-parameter exponential family, straightforward posterior calculations. Moreover, since one of the mixture components is usually vague, mixture priors will often be heavy-tailed and therefore robust. Further robustness and a more rapid reaction to prior-data conflicts can be achieved by adding an extra weakly-informative mixture component. Use of historical prior information is particularly attractive for adaptive trials, as the randomization ratio can then be changed in case of prior-data conflict. Both frequentist operating characteristics and posterior summaries for various data scenarios show that these designs have desirable properties. We illustrate the methodology for a phase II proof-of-concept trial with historical controls from four studies. Robust meta-analytic-predictive priors alleviate prior-data conflicts ' they should encourage better and more frequent use of historical data in clinical trials.
Resumo:
Operationsziel Geschlossene, anatomische Reposition und sichere Fixation von problematischen suprakondylären Typ-III- und Typ-IV-Humerusfrakturen, die mit den herkömmlichen Operationsmethoden nur schwierig geschlossen zu behandeln sind. Indikationen Gemäß der AO-Kinderklassifikation der suprakondylären Humerusfrakturen vom Typ III und IV: Frakturen, welche nicht geschlossen mittels üblicher Repositionsmethoden reponierbar sind sowie Frakturen, die nicht mittels der üblichen, gekreuzten perkutanen Kirschner-Draht-Technik zu fixieren sind. Bei schweren Schwellungszuständen, offener Fraktur oder initial neurologischen und/oder vaskulären Problemen („pulseless pink hand“) sowie bei mehrfachverletzten Kindern, welche eine optimale Rehabilitation benötigen und die Extremität gipsfrei sein sollte. Bei Kindern mit Komorbiditäten (z. B. Anfälle, Spastizität), die eine bessere Stabilität benötigen. Kontraindikationen Prinzipiell keine Kontraindikationen Operationstechnik Im nichtreponierten Zustand unter Durchleuchtungskontrolle Einbringen einer einzelnen Schanz-Schraube in den lateralen (radialen) Aspekt des distalen Fragments, welches sich in der streng seitlichen Röntgenprojektion als „Sand-Uhr“- bzw. Kreisform des Capitulum humeri darstellt. Je nach Größe dieses distalen Fragments kann die Schanz-Schraube rein epiphysär oder metaphysär liegen. Danach in absolut streng seitlicher Projektion des distalen Humerus im Bereich des meta-diaphysären Übergangs Einbohren einer 2. Schanz-Schraube unabhängig von der Ersten, die möglichst rechtwinklig zur Längsachse des Humerus in der a.-p.-Ebene zu liegen kommen sollte, um spätere Manipulationen mittels „Joy-Stick“-Technik zu erleichtern. Sind die beiden Schanz-Schrauben mehr oder weniger in beiden Ebenen parallel, so ist die Fraktur praktisch anatomisch reponiert. Nach erreichter Reposition Feinjustierung aller Achskomponenten. Sicherung der Flexion/Extension mittels einem von radial, distal eingebrachten sog. Anti-Rotations-Kirschner-Drahts, der die Stabilität signifikant erhöht und eine Drehung des distalen Fragments um die einzelne Schanz-Schraube verhindert. Postoperative Behandlung Keine zusätzliche Gipsruhigstellung notwendig. Es sollte eine funktionelle Nachbehandlung erfolgen. Ergebnisse Gemäß unserer Langzeitstudien bewegen die meisten Kinder bereits zum Zeitpunkt der ambulanten Pin-Entfernung in der Frakturambulanz ihren Ellbogen weitgehend normal. Bei einer Follow-up-Zeit über 40 Monate hatten 30/31 Kindern eine seitengleiche Achse und Beweglichkeit.
Resumo:
The goal of asthma treatment is to obtain clinical control and reduce future risks to the patient. To reach this goal in children with asthma, ongoing monitoring is essential. While all components of asthma, such as symptoms, lung function, bronchial hyperresponsiveness and inflammation, may exist in various combinations in different individuals, to date there is limited evidence on how to integrate these for optimal monitoring of children with asthma. The aims of this ERS Task Force were to describe the current practise and give an overview of the best available evidence on how to monitor children with asthma. 22 clinical and research experts reviewed the literature. A modified Delphi method and four Task Force meetings were used to reach a consensus. This statement summarises the literature on monitoring children with asthma. Available tools for monitoring children with asthma, such as clinical tools, lung function, bronchial responsiveness and inflammatory markers, are described as are the ways in which they may be used in children with asthma. Management-related issues, comorbidities and environmental factors are summarised. Despite considerable interest in monitoring asthma in children, for many aspects of monitoring asthma in children there is a substantial lack of evidence.
Resumo:
BACKGROUND Assessment of the proportion of patients with well controlled cardiovascular risk factors underestimates the proportion of patients receiving high quality of care. Evaluating whether physicians respond appropriately to poor risk factor control gives a different picture of quality of care. We assessed physician response to control cardiovascular risk factors, as well as markers of potential overtreatment in Switzerland, a country with universal healthcare coverage but without systematic quality monitoring, annual report cards on quality of care or financial incentives to improve quality. METHODS We performed a retrospective cohort study of 1002 randomly selected patients aged 50-80 years from four university primary care settings in Switzerland. For hypertension, dyslipidemia and diabetes mellitus, we first measured proportions in control, then assessed therapy modifications among those in poor control. "Appropriate clinical action" was defined as a therapy modification or return to control without therapy modification within 12 months among patients with baseline poor control. Potential overtreatment of these conditions was defined as intensive treatment among low-risk patients with optimal target values. RESULTS 20% of patients with hypertension, 41% with dyslipidemia and 36% with diabetes mellitus were in control at baseline. When appropriate clinical action in response to poor control was integrated into measuring quality of care, 52 to 55% had appropriate quality of care. Over 12 months, therapy of 61% of patients with baseline poor control was modified for hypertension, 33% for dyslipidemia, and 85% for diabetes mellitus. Increases in number of drug classes (28-51%) and in drug doses (10-61%) were the most common therapy modifications. Patients with target organ damage and higher baseline values were more likely to have appropriate clinical action. We found low rates of potential overtreatment with 2% for hypertension, 3% for diabetes mellitus and 3-6% for dyslipidemia. CONCLUSIONS In primary care, evaluating whether physicians respond appropriately to poor risk factor control, in addition to assessing proportions in control, provide a broader view of the quality of care than relying solely on measures of proportions in control. Such measures could be more clinically relevant and acceptable to physicians than simply reporting levels of control.
Resumo:
International air travel has already spread Ebola virus disease (EVD) to major cities as part of the unprecedented epidemic that started in Guinea in December 2013. An infected airline passenger arrived in Nigeria on July 20, 2014 and caused an outbreak in Lagos and then Port Harcourt. After a total of 20 reported cases, including 8 deaths, Nigeria was declared EVD free on October 20, 2014. We quantified the impact of early control measures in preventing further spread of EVD in Nigeria and calculated the risk that a single undetected case will cause a new outbreak. We fitted an EVD transmission model to data from the outbreak in Nigeria and estimated the reproduction number of the index case at 9.0 (95% confidence interval [CI]: 5.2-15.6). We also found that the net reproduction number fell below unity 15 days (95% CI: 11-21 days) after the arrival of the index case. Hence, our study illustrates the time window for successful containment of EVD outbreaks caused by infected air travelers.
Resumo:
BACKGROUND Patients requiring anticoagulation suffer from comorbidities such as hypertension. On the occasion of INR monitoring, general practitioners (GPs) have the opportunity to control for blood pressure (BP). We aimed to evaluate the impact of Vitamin-K Antagonist (VKA) monitoring by GPs on BP control in patients with hypertension. METHODS We cross-sectionally analyzed the database of the Swiss Family Medicine ICPC Research using Electronic Medical Records (FIRE) of 60 general practices in a primary care setting in Switzerland. This database includes 113,335 patients who visited their GP between 2009 and 2013. We identified patients with hypertension based on antihypertensive medication prescribed for ≥6 months. We compared patients with VKA for ≥3 months and patients without such treatment regarding BP control. We adjusted for age, sex, observation period, number of consultations and comorbidity. RESULTS We identified 4,412 patients with hypertension and blood pressure recordings in the FIRE database. Among these, 569 (12.9 %) were on Phenprocoumon (VKA) and 3,843 (87.1 %) had no anticoagulation. Mean systolic and diastolic BP was significantly lower in the VKA group (130.6 ± 14.9 vs 139.8 ± 15.8 and 76.6 ± 7.9 vs 81.3 ± 9.3 mm Hg) (p < 0.001 for both). The difference remained after adjusting for possible confounders. Systolic and diastolic BP were significantly lower in the VKA group, reaching a mean difference of -8.4 mm Hg (95 % CI -9.8 to -7.0 mm Hg) and -1.5 mm Hg (95 % CI -2.3 to -0.7 mm Hg), respectively (p < 0.001 for both). CONCLUSIONS In a large sample of hypertensive patients in Switzerland, VKA treatment was independently associated with better systolic and diastolic BP control. The observed effect could be due to better compliance with antihypertensive medication in patients treated with VKA. Therefore, we conclude to be aware of this possible benefit especially in patients with lower expected compliance and with multimorbidity.
Resumo:
BACKGROUND A rapid review, guided by a protocol, was conducted to inform development of the World Health Organization's guideline on personal protective equipment in the context of the ongoing (2013-present) Western African filovirus disease outbreak, with a focus on health care workers directly caring for patients with Ebola or Marburg virus diseases. METHODS Electronic databases and grey literature sources were searched. Eligibility criteria initially included comparative studies on Ebola and Marburg virus diseases reported in English or French, but criteria were expanded to studies on other viral hemorrhagic fevers and non-comparative designs due to the paucity of studies. After title and abstract screening (two people to exclude), full-text reports of potentially relevant articles were assessed in duplicate. Fifty-seven percent of extraction information was verified. The Grading of Recommendations Assessment, Development and Evaluation framework was used to inform the quality of evidence assessments. RESULTS Thirty non-comparative studies (8 related to Ebola virus disease) were located, and 27 provided data on viral transmission. Reporting of personal protective equipment components and infection prevention and control protocols was generally poor. CONCLUSIONS Insufficient evidence exists to draw conclusions regarding the comparative effectiveness of various types of personal protective equipment. Additional research is urgently needed to determine optimal PPE for health care workers caring for patients with filovirus.
Resumo:
HIV-infected women are at increased risk of cervical intra-epithelial neoplasia (CIN) and invasive cervical cancer (ICC), but it has been difficult to disentangle the influences of heavy exposure to HPV infection, inadequate screening, and immunodeficiency. A case-control study including 364 CIN2/3 and 20 ICC cases matched to 1,147 controls was nested in the Swiss HIV Cohort Study (1985-2013). CIN2/3 risk was significantly associated with low CD4+ cell counts, whether measured as nadir (odds ratio (OR) per 100-cell/μL decrease=1.15, 95% CI: 1.08, 1.22), or at CIN2/3 diagnosis (1.10, 95% CI: 1.04, 1.16). An association was evident even for nadir CD4+ 200-349 versus ≥350 cells/μL (OR=1.57, 95% CI: 1.09, 2.25). After adjustment for nadir CD4+, a protective effect of >2-year cART use was seen against CIN2/3 (OR versus never cART use=0.64, 95% CI: 0.42, 0.98). Despite low study power, similar associations were seen for ICC, notably with nadir CD4+ (OR for 50 versus >350 cells/μL= 11.10, 95% CI: 1.24, 100). HPV16-L1 antibodies were significantly associated with CIN2/3, but HPV16-E6 antibodies were nearly exclusively detected in ICC. In conclusion, worsening immunodeficiency, even at only moderately decreased CD4+ cell counts (200-349 CD4+ cells/μL), is a significant risk factor for CIN2/3 and cervical cancer. This article is protected by copyright. All rights reserved.
Resumo:
We present a real-world staff-assignment problem that was reported to us by a provider of an online workforce scheduling software. The problem consists of assigning employees to work shifts subject to a large variety of requirements related to work laws, work shift compatibility, workload balancing, and personal preferences of employees. A target value is given for each requirement, and all possible deviations from these values are associated with acceptance levels. The objective is to minimize the total number of deviations in ascending order of the acceptance levels. We present an exact lexicographic goal programming MILP formulation and an MILP-based heuristic. The heuristic consists of two phases: in the first phase a feasible schedule is built and in the second phase parts of the schedule are iteratively re-optimized by applying an exact MILP model. A major advantage of such MILP-based approaches is the flexibility to account for additional constraints or modified planning objectives, which is important as the requirements may vary depending on the company or planning period. The applicability of the heuristic is demonstrated for a test set derived from real-world data. Our computational results indicate that the heuristic is able to devise optimal solutions to non-trivial problem instances, and outperforms the exact lexicographic goal programming formulation on medium- and large-sized problem instances.
Resumo:
BACKGROUND In 2012, the levels of chlamydia control activities including primary prevention, effective case management with partner management and surveillance were assessed in 2012 across countries in the European Union and European Economic Area (EU/EEA), on initiative of the European Centre for Disease Control (ECDC) survey, and the findings were compared with those from a similar survey in 2007. METHODS Experts in the 30 EU/EEA countries were invited to respond to an online questionnaire; 28 countries responded, of which 25 participated in both the 2007 and 2012 surveys. Analyses focused on 13 indicators of chlamydia prevention and control activities; countries were assigned to one of five categories of chlamydia control. RESULTS In 2012, more countries than in 2007 reported availability of national chlamydia case management guidelines (80% vs. 68%), opportunistic chlamydia testing (68% vs. 44%) and consistent use of nucleic acid amplification tests (64% vs. 36%). The number of countries reporting having a national sexually transmitted infection control strategy or a surveillance system for chlamydia did not change notably. In 2012, most countries (18/25, 72%) had implemented primary prevention activities and case management guidelines addressing partner management, compared with 44% (11/25) of countries in 2007. CONCLUSION Overall, chlamydia control activities in EU/EEA countries strengthened between 2007 and 2012. Several countries still need to develop essential chlamydia control activities, whereas others may strengthen implementation and monitoring of existing activities.