63 research outputs found
Induced-Innovation and Invasive Species Management
Public policy for managing invasive species has largely focused on preventive measures prior to detection (stage 1) and on the use of chemical/mechanical or biological control measures after the establishment and dispersion of the invasive species (stage 2). Optimal management policy depends both on the initial stock of the invasive species and on the costs associated with conventional control measures. However, little attention has focused on how an induced technology such as Bt corn and Bt cotton is developed and adopted by farmers (stage 3), or how it affects the manageability of economic and ecological damages from an invasive species. This analysis evaluates the optimal allocation of management resources between preventive and control measures for invasive species by incorporating induced technology under uncertainty into a conventional dynamic model of invasive species management.Invasive species, preventive measures, control measures, induced technology, hazard function, optimal control, comparative dynamic analysis, Environmental Economics and Policy, Production Economics,
Unraveling the non-senescence phenomenon in Hydra
Unlike other metazoans, Hydra does not experience the distinctive rise in mortality with age known as senescence, which results from an increasing imbalance between cell damage and cell repair. We propose that the Hydra controls damage accumulation mainly through damage-dependent cell selection and cell sloughing. We examine our hypothesis with a model that combines cellular damage with stem cell renewal, differentiation, and elimination. The Hydra individual can be seen as a large single pool of three types of stem cells with some features of differentiated cells. This large stem cell community prevents âcellular damage drift,â which is inevitable in complex conglomerate (differentiated) metazoans with numerous and generally isolated pools of stem cells. The process of cellular damage drift is based on changes in the distribution of damage among cells due to random events, and is thus similar to MullerŚłs ratchet in asexual populations. Events in the model that are sources of randomness include budding, cellular death, and cellular damage and repair. Our results suggest that non-senescence is possible only in simple Hydra-like organisms which have a high proportion and number of stem cells, continuous cell divisions, an effective cell selection mechanism, and stem cells with the ability to undertake some roles of differentiated cells
Safety margin assessment after microwave ablation of liver tumors: inter- and intrareader variability
Background. The aim of the study was to evaluate the inter- and intrareader variability of the safety margin assessment after microwave ablation of liver tumors using post-procedure computed tomography (CT) images as well as to determine the sensitivity and specificity of identification remnant tumor tissue. Patients and methods. A retrospective analysis of 58 patients who underwent microwave ablation (MWA) of primary or secondary liver malignancies (46 hepatocellular carcinoma, 9 metastases of a colorectal cancer and 3 metastases of pancreatic cancer) between September 2017 and June 2019 was conducted. Three readers estimated the minimal safety margin in millimeters using side-by-side comparison of the 1-day pre-ablation CT and 1-day postablation CT and judged whether ablation was complete or incomplete. One reader estimated the safety margin again after 6 weeks. Magnetic resonance imaging (MRI) after 6 weeks was the gold standard. Results. The intraclass correlation coefficient (ICC) for estimation of the minimal safety margin of all three readers was 0.357 (95%-confidence interval 0.194-0.522). The ICC for repeated assessment (reader 1) was 0.774 (95%-confidence interval 0.645-0.860). Sensitivity and specificity of the detection of complete tumor ablation, defined as no remnant tumor tissue in 6 weeks follow-up MRI, were 93%/82%/82% and 33%/17%/83%, respectively. Conclusions. In clinical practice, the safety margin after liver tumor ablation is often assessed using side-by-side comparison of CT images. In the study, we were able to show, that this technique has a poor reliability (ICC 0.357). From our point of view, this proves the necessity of new technical procedures for the assessment of the safety distance
Psychological factors as risk factors for poor hip function after total hip arthroplasty
Recovery after total hip arthroplasty (THA) is influenced by several psychological aspects, such as depression, anxiety, resilience, and personality traits. We hypothesized that preoperative depression impedes early functional outcome after THA (primary outcome measure). Additional objectives were perioperative changes in the psychological status and their influence on perioperative outcome. This observational study analyzed depression, anxiety, resilience, and personality traits in 50 patients after primary unilateral THA. Hip functionality was measured by means of the Harris Hip Score. Depression, state anxiety, and resilience were evaluated preoperatively as well as 1 and 5 weeks postoperatively. Trait anxiety and personality traits were measured once preoperatively. Patients with low depression and anxiety levels had significantly better outcomes with respect to early hip functionality. Resilience and personality traits did not relate to hip functionality. Depression and state anxiety levels significantly decreased within the 5-week stay in the acute and rehabilitation clinic, whereas resilience remained at the same level. Our study suggests that low depression and anxiety levels are positively related to early functionality after THA. Therefore, perioperative measurements of these factors seem to be useful to provide the best support for patients with risk factors
Changes in gadoxetic-acid-enhanced MR imaging during the first year after irreversible electroporation of malignant hepatic tumors
Purpose To evaluate the appearance and size of ablation zones in gadoxetic-acid-enhanced magnetic resonance imaging (MRI) during the first year after irreversible electroporation (IRE) of primary or secondary hepatic malignancies and to investigate potential correlations to clinical features. Material and methods The MRI-appearance of the ablation area was assessed 1-3 days, 6 weeks, 3 months, 6 months, 9 months and 1 year after IRE. The size of the ablation zone and signal intensities of each follow-up control were compared. Moreover, relationships between clinical features and the MRI-appearance of the ablation area 1-3 days after IRE were analyzed. Results The ablation zone size decreased from 5.6 +/- 1.4 cm (1-3 days) to 3.7 +/- 1.2 cm (1 year). A significant decrease of central hypointensities was observed in T2-blade- (3 months), T2 haste- (6 weeks; 3 months; 6 months; 1 year), T1 arterial phase- (3 months; 1 year), and diffusion-sequences (6 weeks; 3 months; 6 months; 9 months; 1 year). The unenhanced T1-sequences showed significantly increasing central hypointensities (6 weeks; 3 months; 6 months; 9 months; 1 year). Significantly increasing peripheral hypointensities were detected in T1 arterial phase- (3 months; 6 months; 9 months; 1 year) and in T1 portal venous phase-sequences (6 weeks; 3 months; 6 months; 9 months; 1 year). Peripheral hypointensities of unenhanced T1-sequences decreased significantly 1 year after IRE. 1-3 days after IRE central T1 portal venous hypo- or isointensities were detected significantly more often than hyperintensities, if more than 3 IRE electrodes were used. Conclusion Hepatic IRE results in continuous reduction of ablation zone size during the first postinterventional year. In addition to centrally decreasing T1-signal and almost steadily increasing signal in the enhanced T2 haste-, diffusion- and T1 arterial phase-sequences, there is a trend toward long-term decreasing T1 arterial- and portal venous MRI-signal intensity of the peripheral ablation area, probably representing a region of reversible electroporation
Injury Pattern and Current Early Clinical Care of Pediatric Polytrauma Comparing Different Age Groups in a Level I Trauma Center
Introduction: Pediatric polytrauma is a complex condition with unique characteristics and requirements for early clinical care. This study aimed to analyze the injury patterns, early clinical care, and outcomes of pediatric polytrauma patients in a Level I trauma center. The focus was on evaluation between different age groups and the recognition of injuries as potential factors influencing outcomes. Methods: A prospective cohort study model of pediatric polytrauma patients (ISS â„ 16) was conducted over a 13-year period, stratified by age groups (Group A: 0â5 years; Group B: 6â10 years; Group C: 11â15 years; and Group D: 16â18 years). A comparison of the groups was conducted to examine variations in early clinical care, trauma mechanisms, distribution of affected body regions (as per AIS and ISS criteria), and trauma-related mortality. Additionally, factors contributing to mortality were evaluated. Results: The median age of patients was 16 years, with a male predominance (64.7%). The Injury Severity Score (ISS) varied across age groups, with no significant difference. The 30-day mortality rate was 19.0%, with no significant age-related differences. Trauma mechanisms varied across age groups, with motor vehicle accidents being the most common mechanism in all age groups except 0â5 years, where falls were prevalent. Analysis of injury patterns by AIS body regions indicated that head trauma was a significant predictor of mortality (Hazard Ratio 2.894, p < 0.001), while chest, abdominal, and extremity trauma showed no significant association with mortality. Multiple regression analysis identified the ISS and preclinical GCS as valid predictors of mortality (p < 0.001 and p = 0.006, respectively). Conclusions: While age-related differences in injury severity and clinical interventions were limited, head trauma emerged as a critical predictor of mortality. Early recognition and management of head injuries are crucial in improving outcomes. Additionally, the ISS and preclinical GCS were identified as valid predictors of mortality, emphasizing the importance of early assessment and resuscitation. A tailored approach to pediatric polytrauma care, considering both age and injury patterns, might contribute to survival benefits in this vulnerable populatio
Evaluation of Alterations to Bile Ducts and Laboratory Values During the First 3 Months After Irreversible Electroporation of Malignant Hepatic Tumors
Purpose: To assess the incidence and evolution of biliary alterations adjacent to the ablation area in patients with hepatic malignancies during the first 3 months after percutaneous irreversible electroporation (IRE) and to investigate associated changes in laboratory values. Material and Methods: Bile ducts located within a <1.0 cm radius of the ablation zone were analyzed in 45 patients by preinterventional and postinterventional MRI (1-3 days, 6 weeks, and 3 months after IRE). Moreover, levels of alkaline phosphatase (AP) and serum bilirubin (SB) were examined for evidence of bile duct injury. Biliary alterations and the presence of postinterventional-elevated laboratory levels were correlated with features of the lesions, patients, ablation procedures, and laboratory values. Results: A total of 80 bile ducts were located within a 1.0 cm radius of the ablation zone: 59 were encased, 16 were abutting and 5 were located within a radius of 0.1-1.0 cm of the ablation area. In total, 38 biliary injuries (narrowing, n=22; dilatation, n=14; biloma, n=2) were detected, 3 cases of narrowing occurred for the first time 6 weeks and 3 months after IRE, 21 alterations (dilatation: n=9; narrowing; n=10; biloma: n=2) had resolved during the first 6 weeks, 1 alteration (dilatation: n=1) had resolved by the last follow-up control. Three months after IRE, 19 patients showed elevated levels of AP, whereas SB levels were increased in 10 cases. No significant association between biliary alterations or postinterventional-elevated laboratory values and the investigated characteristics of lesions, patients, ablation procedures or laboratory values could be proven. Conclusion: Different alterations of bile ducts adjacent to an IRE ablation zone are common, of which dilatation and especially narrowing commonly represent a long-term complication after IRE. Moreover, a definite correlation between the frequently observed prolonged post-ablative elevation of AP- and SB-levels and the postinterventional biliary alterations could not be proven
Tuberculostearic Acid-Containing Phosphatidylinositols as Markers of Bacterial Burden in Tuberculosis
One-fourth of the global human population is estimated to be infected with strains of the Mycobacterium tuberculosis complex (MTBC), the causative agent of tuberculosis (TB). Using lipidomic approaches, we show that tuberculostearic acid (TSA)-containing phosphatidylinositols (PIs) are molecular markers for infection with clinically relevant MTBC strains and signify bacterial burden. For the most abundant lipid marker, detection limits of âŒ10 colony forming units (CFUs) and âŒ10 CFUs for bacterial and cell culture systems were determined, respectively. We developed a targeted lipid assay, which can be performed within a day including sample preparationâroughly 30-fold faster than in conventional methods based on bacterial culture. This indirect and culture-free detection approach allowed us to determine pathogen loads in infected murine macrophages, human neutrophils, and murine lung tissue. These marker lipids inferred from mycobacterial PIs were found in higher levels in peripheral blood mononuclear cells of TB patients compared to healthy individuals. Moreover, in a small cohort of drug-susceptible TB patients, elevated levels of these molecular markers were detected at the start of therapy and declined upon successful anti-TB treatment. Thus, the concentration of TSA-containing PIs can be used as a correlate for the mycobacterial burden in experimental models and in vitro systems and may prospectively also provide a clinically relevant tool to monitor TB severity
Severe COVID-19 pneumonia: Perfusion analysis in correlation with pulmonary embolism and vessel enlargement using dual-energy CT data
Background
Gas exchange in COVID-19 pneumonia is impaired and vessel obstruction has been suspected to cause ventilation-perfusion mismatch. Dual-energy CT (DECT) can depict pulmonary perfusion by regional assessment of iodine uptake.
Objective
The purpose of this study was the analysis of pulmonary perfusion using dual-energy CT in a cohort of 27 consecutive patients with severe COVID-19 pneumonia.
Method
We retrospectively analyzed pulmonary perfusion with DECT in 27 consecutive patients (mean age 57 years, range 21â73; 19 men and 8 women) with severe COVID-19 pneumonia. Iodine uptake (IU) in regions-of-interest placed into normally aerated lung, ground-glass opacifications (GGO) and consolidations was measured using a dedicated postprocessing software. Vessel enlargement (VE) within opacifications and presence of pulmonary embolism (PE) was assessed by subjective analysis. Linear mixed models were used for statistical analyses.
Results
Compared to normally aerated lung 106/151 (70.2%) opacifications without upstream PE demonstrated an increased IU, 9/151 (6.0%) an equal IU and 36/151 (23.8%) a decreased IU. The estimated mean iodine uptake (EMIU) in opacifications without upstream PE (GGO 1.77 mg/mL; 95%-CI: 1.52â2.02; p = 0.011, consolidations 1.82 mg/mL; 95%-CI: 1.56â2.08, p = 0.006) was significantly higher compared to normal lung (1.22 mg/mL; 95%-CI: 0.95â1.49). In case of upstream PE, EMIU of opacifications (combined GGO and consolidations) was significantly decreased compared to normal lung (0.52 mg/mL; 95%-CI: -0.07â1.12; p = 0.043). The presence of VE in opacifications correlated significantly with iodine uptake (p<0.001).
Conclusions
DECT revealed the opacifications in a subset of patients with severe COVID-19 pneumonia to be perfused non-uniformly with some being hypo- and others being hyperperfused. Mean iodine uptake in opacifications (both ground-glass and consolidation) was higher compared to normally aerated lung except for areas with upstream pulmonary embolism. Vessel enlargement correlated with iodine uptake: In summary, in a cohort of 27 consecutive patients with severe COVID-19 pneumonia, dual-energy CT demonstrated a wide range of iodine uptake in pulmonary ground-glass opacifications and consolidations as a surrogate marker for hypo- and hyperperfusion compared to normally aerated lung. Applying DECT to determine which pathophysiology is predominant might help to tailor therapy to the individual patientÂŽs needs
Randomized trial of a GPIIb/IIIa platelet receptor blocker in refractory unstable angina
BACKGROUND: Patients with unstable angina despite intensive medical therapy, ie, refractory angina, are at high risk for developing thrombotic complications: myocardial infarction or coronary occlusion during percutaneous transluminal coronary angioplasty (PTCA). Chimeric 7E3 (c7E3) Fab is an antibody fragment that blocks the platelet glycoprotein (GP) IIb/IIIa receptor and potently inhibits platelet aggregation. METHODS AND RESULTS: To evaluate whether potent platelet inhibition could reduce these complications, 60 patients with dynamic ST-T changes and recurrent pain despite intensive medical therapy were randomized to c7E3 Fab or placebo. After initial angiography had demonstrated a culprit lesion suitable for PTCA, placebo or c7E3 Fab was administered as 0.25 mg/kg bolus injection followed by 10 micrograms/min for 18 to 24 hours until 1 hour after completion of second angiography and PTCA. During study drug infusion, ischemia occurred in 9 c7E3 Fab and 16 placebo patients (P = .06). During hospital stay, 12 major events occurred in 7 placebo patients (23%), including 1 death, 4 infarcts, and 7 urgent interventions. In the c7E3 Fab group, only 1 event (an infarct) occurred (3%, P = .03). Angiography showed improved TIMI flow in 4 placebo and 6 c7E3 Fab patients and worsening of flow in 3 placebo patients but in none of the c7E3 Fab patients. Quantitative analysis showed significant improvement of the lesion in the patients treated with c7E3 Fab, which was not observed in the placebo group, although the difference between the two treatment groups was not significant. Measurement of platelet function and bleeding time demonstrated > 90% blockade of GPIIb/IIIa receptors, > 90% reduction of ex vivo platelet aggregation to ADP, and a significantly prolonged bleeding time during c7E3 Fab infusion, without excess bleeding. CONCLUSIONS: Combined therapy with c7E3 Fab, heparin, and aspirin appears safe. These pilot study results support the concept that effective blockade of the platelet GPIIb/IIIa receptors can reduce myocardial infarction and facilitate PTCA in patients with refractory unstable angina
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