357 research outputs found
Is there a relation between type of primary melanoma treatment and the development of intralymphatic metastasis? A review of the literature
AbstractBackgroundIntralymphatic metastases (ILM) originate from tumor cell emboli entrapped in dermal lymphatics between primary tumor and regional lymph node basin. Because of this origin, sentinel lymph node biopsy (SLNB) might increase ILM by restricting lymph flow.MethodsPubmed, Embase, Cochrane and Medline were searched for articles on ILM between 1980 and September 2014. ILM Incidences were calculated after wide local excision (WLE), excision with elective lymph node dissection (ELND) or therapeutic lymph node dissection (TLND), WLE with SLNB with or without completion lymph node dissection (CLND) and delayed lymph node dissection (DLND) for patients developing nodal metastasis during follow-up.ResultsIn 36 studies, 14,729 patients underwent WLE, 1682 patients WLE/ELND, 362 patients WLE/DLND and 11,201 patients WLE/SLNB. On meta-analysis, ILM occurrence was 3.4% (95% CI 2.8–4.2%). ILM occurred most frequently in the WLE/DLND group (5.5%, 95% CI 3.5–8.7%), followed by WLE/ELND (4.7%, 95% CI 3.1–7.0%), WLE/SLNB (4.5%, 95% CI 3.5–5.7%) and WLE alone (1.9%, 95% CI 1.4–2.7%). 1330 SLNB+ patients were identified and 5783 SLNB− patients. For these groups, on meta-analysis, ILM recurrence was 13.2% (95% CI 10.8–16.2%) and 3.4% (95% CI 2.5–4.5%), respectively (p=0.01).ConclusionIn this review SLNB is associated with an increase of ILM with an incidence of 1.9% for WLE vs. 3.4% for SNLB−. Selection bias in this review cannot be excluded. However, ILM occur four times more frequently after SLNB+ than SLNB− procedures and more often after SLNB+/CLND than WLE/DLND or WLE/ELND. ILM should therefore be viewed as a bio-marker of aggressive primary disease.SynopsisSentinel lymph node biopsy is thought to increase intralymphatic metastasis by restricting lymph flow. This review demonstrates that there is an increase in metastasis, but this result has to be interpreted with caution due to possible selection bias. Aggressive tumor characteristics are likely the cause of this increase
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DEMONSTRATION OF LEACHXS/ORCHESTRA CAPABILITIES BY SIMULATING CONSTITUENT RELEASE FROM A CEMENTITIOUS WASTE FORM IN A REINFORCED CONCRETE VAULT
The objective of the work described in this report is to demonstrate the capabilities of the current version of LeachXS{trademark}/ORCHESTRA for simulating chemical behavior and constituent release processes in a range of applications that are relevant to the CBP. This report illustrates the use of LeachXS{trademark}/ORCHESTRA for the following applications: (1) Comparing model and experimental results for leaching tests for a range of cementitious materials including cement mortars, grout, stabilized waste, and concrete. The leaching test data includes liquid-solid partitioning as a function of pH and release rates based on laboratory column, monolith, and field testing. (2) Modeling chemical speciation of constituents in cementitious materials, including liquid-solid partitioning and release rates. (3) Evaluating uncertainty in model predictions based on uncertainty in underlying composition, thermodynamic, and transport characteristics. (4) Generating predominance diagrams to evaluate predicted chemical changes as a result of material aging using the example of exposure to atmospheric conditions. (5) Modeling coupled geochemical speciation and diffusion in a three layer system consisting of a layer of Saltstone, a concrete barrier, and a layer of soil in contact with air. The simulations show developing concentration fronts over a time period of 1000 years. (6) Modeling sulfate attack and cracking due to ettringite formation. A detailed example for this case is provided in a separate article by the authors (Sarkar et al. 2010). Finally, based on the computed results, the sensitive input parameters for this type of modeling are identified and discussed. The chemical speciation behavior of substances is calculated for a batch system and also in combination with transport and within a three layer system. This includes release from a barrier to the surrounding soil as a function of time. As input for the simulations, the physical and chemical properties of the materials are used. The test cases used in this demonstration are taken from Reference Cases for Use in the Cementitious Barriers Partnership (Langton et al. 2009). Before it is possible to model the release of substances from stabilized waste or radioactive grout through a cement barrier into the engineered soil barrier or natural soil, the relevant characteristics of such materials must be known. Additional chemical characteristics are needed for mechanistic modeling to be undertaken, not just the physical properties relevant for modeling of transport. The minimum required properties for modeling are given in Section 5.0, 'Modeling the chemical speciation of a material'
Rollator usage lets young individuals switch movement strategies in sit-to-stand and stand-to-sit tasks
The transitions between sitting and standing have a high physical and coordination demand, frequently causing falls in older individuals. Rollators, or four-wheeled walkers, are often prescribed to reduce lower-limb load and to improve balance but have been found a fall risk. This study investigated how rollator support affects sit-to-stand and stand-to-sit movements. Twenty young participants stood up and sat down under three handle support conditions (unassisted, light touch, and full support). As increasing task demands may affect coordination, a challenging floor condition (balance pads) was included. Full-body kinematics and ground reaction forces were recorded, reduced in dimensionality by principal component analyses, and clustered by k-means into movement strategies. Rollator support caused the participants to switch strategies, especially when their balance was challenged, but did not lead to support-specific strategies, i.e., clusters that only comprise light touch or full support trials. Three strategies for sit-to-stand were found: forward leaning, hybrid, and vertical rise; two in the challenging condition (exaggerated forward and forward leaning). For stand-to-sit, three strategies were found: backward lowering, hybrid, and vertical lowering; two in the challenging condition (exaggerated forward and forward leaning). Hence, young individuals adjust their strategy selection to different conditions. Future studies may apply this methodology to older individuals to recommend safe strategies and ultimately reduce falls
Diet Quality and Upper Gastrointestinal Cancers Risk:A Meta-Analysis and Critical Assessment of Evidence Quality
We aimed to assess the effect of a high-quality diet on the risk of upper gastrointestinal cancer and to evaluate the overall quality of our findings by searching PubMed, EMBASE, Web of Science, Cochrane, and the references of related articles to February 2020. Two reviewers independently retrieved the data and performed the quality assessments. We defined the highest-quality diet as that with the lowest Diet Inflammatory Index category and the highest Mediterranean Diet Score category. Overall odds ratios and 95% confidence intervals were estimated for upper gastrointestinal cancer risk comparing the highest- versus lowest-diet quality. A random-effects meta-analysis was then applied with Review Manager, and the quality of the overall findings was evaluated with the Grading of Recommendations Assessment, Development, and Evaluation approach. The highest-quality diets were significantly associated with reduced risk of upper gastrointestinal cancers, achieving odds ratios of 0.59 (95% confidence interval: 0.48-0.72) for the Diet Inflammatory Index, pooling the findings from nine studies, and 0.72 (95% confidence interval: 0.61-0.88) for the Mediterranean Diet Score, pooling the findings from 11 studies. We observed a minimum of 69% heterogeneity in the pooled results. The pooled results were graded as low quality of evidence. Although it may be possible to offer evidence-based general dietary advice for the prevention of upper gastrointestinal cancers, the evidence is currently of insufficient quality to develop dietary recommendations
Cost-Effectiveness of Pre-Exposure Prophylaxis (Prep) in Preventing HIV-1 Infections in Rural Zambia: A Modeling Study
Background: Pre-exposure prophylaxis (PrEP) with tenofovir and emtricitabine effectively prevents new HIV infections. The optimal scenario for implementing PrEP where most infections are averted at the lowest cost is unknown. We determined the impact of different PrEP strategies on averting new infections, prevalence, drug resistance and cost-effectiveness in Macha, a rural setting in Zambia. Methods: A deterministic mathematical model of HIV transmission was constructed using data from the Macha epidemic (antenatal prevalence 7.7%). Antiretroviral therapy is started at CD4/mm 3 . We compared the number of infections averted, cost-effectiveness, and potential emergence of drug resistance of two ends of the prioritization spectrum: prioritizing PrEP to half of the most sexually active individuals (5-15% of the total population), versus randomly putting 40-60% of the total population on PrEP. Results: Prioritizing PrEP to individuals with the highest sexual activity resulted in more infections averted than a non-prioritized strategy over ten years (31% and 23% reduction in new infections respectively), and also a lower HIV prevalence after ten years (5.7%, 6.4% respectively). The strategy was very cost-effective at $323 per quality adjusted life year gained and appeared to be both less costly and more effective than the non-prioritized strategy. The prevalence of drug resistance due to PrEP was as high as 11.6% when all assumed breakthrough infections resulted in resistance, and as low as 1.3% when 10% of breakthrough infections resulted in resistance in both our prioritized and non-prioritized scenarios. Conclusions: Even in settings with low test rates and treatment retention, the use of PrEP can still be a useful strategy in averting infections. Our model has shown that PrEP is a cost-effective strategy for reducing HIV incidence, even when adherence is suboptimal and prioritization is imperfect
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