Search

Ferritic stainless steels armored with borides had their endurance tested in demanding both abrasive and corrosive environment. The degradation was investigated through a very aggressive plate-on-cylinder wear test in water-based drilling mud containing chlorides, which was designed to simulate, in laboratorial scale, the corrosive tribosystem found in the wear of risers and casings used in deep water oil exploitation. A commercially-grade 430 ferritic stainless steel containing boron content far beyond its solubility limity, namely 1.2 and 3.5 wt.%, was processed by spray-forming to induce a ferritic stainless steel matrix protected by a boride skeleton. Additional corrosion assessment was performed by potentiodynamic polarization and electrochemical impedance spectroscopy in 0.27 M KCl solution, since KCl is a common clay swelling inhibitor. For comparison, API 5L X80 steel was also included since this material is used in risers and casings manufacture. The addition of boron (1.2 and 3.5 wt.%) led to the formation of microstructures composed of an α-ferrite matrix with homogeneously distributed M2B-type borides of different morphologies. Electrochemical tests revealed high corrosion resistance of the alloy with 1.2 wt.% B. However, the alloy with 3.5 wt.% B showed a considerable decrease in corrosion resistance due to Cr-depletion of the ferritic matrix given the M2B formation richer in Cr. Therefore, the alloy with 1.2 wt.% B offered the best tribocorrosion resistance.

The microstructure of Fe76·5Nb8·5B15 (at.%) ultrafine eutectic (UE) coatings were processed by laser cladding, then the bulk alloy coating and wear debris were evaluated by advanced electron microscopy techniques in order to understand the ultrafine matrix and nanoscale intermetallic sub-micron and nanoscale phases formed, as a result of rapid solidification. In addition, according to the laser cladding processing parameters used, the coatings presented nanoscale borides that increased mechanical properties, with the coating michohardness values reached being four times higher than those of the AISI mild steel substrate. Combined with the sliding speeds, it played an important role in the definition of different wear mechanisms. The wear performance of the coatings and substrate was evaluated by three-body wear tests using a pin-on-disc device. It can be seen at lowest sliding speed a plastic deformation and for higher slidding speed, an accumulation of debris on the laser clad coating surface. Different wear mechanisms were observed in the coatings samples: abrasive, adhesive, shearing and delamination. The presence of oxide particles, responsible for the formation of a tribofilm, was also observed for some coatings. Debris nanoparticles from 10 to 100 nm, resulting from fracture or breakage of the coatings during wear tests, were also be identified as Fe-based and oxide nanoparticles. Thus, the Fe–Nb–B ultrafine eutectics laser clad coatings showed wear resistance properties comparable to or even superior to commercial alloys and other materials processed by rapid solidification.

With the increase in cultivated areas, one of the great challenges faced by eucalyptus growers is abiotic stresses, especially because new areas are often affected by water deficit. Therefore, the identification of tolerant genotypes is important to overcome this problem. Thus, the objective of this work was to characterize the germinative and physiological performance of eucalyptus species under abiotic stress. Four Eucalyptus species (E. brassiana, E. camaldulensis, E. saligna, and E. urophylla) were evaluated in two experiments. In the first experiment, the germination potential was assessed under two temperatures (25 and 35 °C) and 11 water potentials of the substrate: 0 (deionized water), -0.05, -0.10, -0.15, -0.20, -0.25, -0.30, -0.40, -0.60, -0.80, and -1.0 MPa. In the second experiment, the species were evaluated in a protected environment under two water regimes comprised by 60% and 20% of the maximum water retention capacity by the soil of the pots. Regarding germination, E. saligna was the most sensitive species to stress, showing only 48% germination on 0 MPa potential (35 °C) and under substrate water deficit it reduced 50% germination on -0.21 MPa (25 °C) and -0.16 MPa potential (35 °C). On the other hand, E. brassiana maintained germination at both temperatures and reduced half of its germination at potentials of -0.33 MPa (25 °C) and -0.32 MPa (35 °C). In protected environment, the physiological metabolism of plants decreased under lower water availability. E. saligna was the species with the highest reduction for the rate of net assimilation and efficiency in water use. In addition, E. camaldulensis showed better physiological performance under water deficit. Thus, E. brassiana and E. camaldulensis would be the most suitable species to be used for breeding program aiming to improve water deficit tolerance. E. saligna is indicated for places with a mild climate and with good water availability. The behavior of the species between the experiments showed that under certain conditions there are correspondences in performance, which indicates that this type of experiment assists in the characterization of species, especially when considering the establishment and initial plant development.

The Atlantic Forest is a Neotropical biome encompassing mainly Brazil's coastline and parts of Paraguay, Uruguay, and Argentina, but today surviving largely in small degraded patches and protected areas. Being a region under threat of extinction of its biological components, little is known about how climate change could influence the biodiversity, dynamics, and stability of this ecosystem. Here, we analyze the response of tree-growth dynamics to regional climate variability and drought, both in temporal and spatial scale. For this purpose, five Cedrela spp forest sites located in the biogeographic region ‘Serra do Mar’ (AFSM) in southeastern Brazil was considered. This region contains the best-preserved secondary forests of the Atlantic Forest biome, a fact that represents a natural laboratory to ascertain the environmental influence on the tree development through large spatial scales. Correlation and regression analysis were used to explore the relationship between growth and rainfall, air temperature, and a drought index. Results indicate that tree growth performance is highly dependent to the dry season rainfall amounts in the most humid sector of the gradient, while sites settled in areas of lower summer temperatures, rainfall during the warm-rainy season is the main determining factor influencing tree-growth dynamics. This implies that the same environmental factor (rainfall) affect differentially the growth of Cedrela sites depending on the sector in the gradient in which they are. We found that the population located at the highest-altitude site experienced a growth decline in recent decades linked to increases of winter regional warming, being more sensitivity to long periods of drought (6–10 years). In summary, the seasonal response of cambium activity in AFSM trees to rainfall varies across a climatic gradient. These results are crucial to understand how the present and future global change may differentially impact on tree population dynamics of montane Neotropical forests. Keywords: Tropical dendroecology, Biogeography, Cedro, Serra do Mar, Neotropical forest

Introduction: Several presentations of neurologic complications caused by JC virus (JCV) in human immunodeficiency virus (HIV)-infected patients have been described and need to be distinguished from the “classic” form of progressive multifocal leukoencephalopathy (PML). The objectives of this study were: 1) to describe the spectrum and frequency of presentations of JCV-associated central nervous system (CNS) diseases; 2) identify factors associated with in-hospital mortality of patients with JCV-associated CNS disease; and 3) to estimate the overall mortality of this population. Material and methods: This was a retrospective study of HIV-infected patients admitted consecutively for JCV-associated CNS diseases in a referral teaching center in Sao Paulo, Brazil, from 2002 to 2007. All patients with laboratory confirmed JCV-associated CNS diseases were included using the following criteria: compatible clinical and radiological features associated with the presence of JCV DNA in the cerebrospinal fluid. JCV-associated CNS diseases were classified as follows: 1) classic PML; 2) inflammatory PML; and 3) JC virus granule cell neuronopathy (GCN). Results: We included 47 cases. JCV-associated CNS diseases were classified as follows: 1) classic PML: 42 (89%); 2) inflammatory PML: three (6%); and 3) JC virus GCN: four (9%). Nosocomial pneumonia (p = 0.003), previous diagnosis of HIV infection (p = 0.03), and imaging showing cerebellar and/or brainstem involvement (p = 0.02) were associated with in-hospital mortality. Overall mortality during hospitalization was 34%. Conclusions: Novel presentations of JCV-associated CNS diseases were observed in our setting; nosocomial pneumonia, previous diagnosis of HIV infection, and cerebellar and/or brainstem involvement were associated with in-hospital mortality; and overall mortality was high. Keywords: JC virus, Leukoencephalopathy, progressive multifocal, Diagnosis, Acquired immunodeficiency syndrome, Brazil

Objetivo: Evaluar la eficiencia predictiva de modelos estadísticos paramétricos y no paramétricos para predecir episodios críticos de contaminación por material particulado PM10 del día siguiente, que superen en Santiago de Chile la norma de calidad diaria. Una predicción adecuada de tales episodios permite a la autoridad decretar medidas restrictivas que aminoren la gravedad del episodio, y consecuentemente proteger la salud de la comunidad. Método: Se trabajó con las concentraciones de material particulado PM10 registradas en una estación asociada a la red de monitorización de la calidad del aire MACAM-2, considerando 152 observaciones diarias de 14 variables, y con información meteorológica registrada durante los años 2001 a 2004. Se ajustaron modelos estadísticos paramétricos Gamma usando el paquete estadístico STATA v11, y no paramétricos usando una demo del software estadístico MARS v 2.0 distribuida por Salford-Systems. Resultados: Ambos métodos de modelación presentan una alta correlación entre los valores observados y los predichos. Los modelos Gamma presentan mejores aciertos que MARS para las concentraciones de PM10 con valores Objective: To evaluate the predictive efficiency of two statistical models (one parametric and the other non-parametric) to predict critical episodes of air pollution exceeding daily air quality standards in Santiago, Chile by using the next day PM10 maximum 24h value. Accurate prediction of such episodes would allow restrictive measures to be applied by health authorities to reduce their seriousness and protect the community´s health. Methods: We used the PM10 concentrations registered by a station of the Air Quality Monitoring Network (152 daily observations of 14 variables) and meteorological information gathered from 2001 to 2004. To construct predictive models, we fitted a parametric Gamma model using STATA v11 software and a non-parametric MARS model by using a demo version of Salford-Systems. Results: Both models showed a high correlation between observed and predicted values. However, the Gamma model predicted PM10 values below 240µg/m³ more accurately than did MARS. The latter was more efficient in predicting PM10 values above 240µg/m³ throughout the study period. Conclusion: MARS models are more efficient in predicting extreme PM10 values and allow health authorities to adopt preventive methods to reduce the effects of these levels on the population´s health. The reason for this greater accuracy may be that MARS models correct variations in the series over time, thus better fitting the curve associated with PM10 concentrations.

INTRODUCTION: Several presentations of neurologic complications caused by JC virus (JCV) in human immunodeficiency virus (HIV)-infected patients have been described and need to be distinguished from the "classic" form of progressive multifocal leukoencephalopathy (PMl). The objectives of this study were: 1) to describe the spectrum and frequency of presentations of JCV-associated central nervous system (CNS) diseases; 2) identify factors associated with in-hospital mortality of patients with JCV-associated CNS disease; and 3) to estimate the overall mortality of this population. MATERIAL AND METHODS: This was a retrospective study of HIV-infected patients admitted consecutively for JCVassociated CNS diseases in a referral teaching center in São Paulo, Brazil, from 2002 to 2007. All patients with laboratory confirmed JCV-associated CNS diseases were included using the following criteria: compatible clinical and radiological features associated with the presence of JCV DNA in the cerebrospinal fluid. JCV-associated CNS diseases were classified as follows: 1) classic PMl; 2) inflammatory PMl; and 3) JC virus granule cell neuronopathy (GCN). RESULTS: We included 47 cases. JCV-associated CNS diseases were classified as follows: 1) classic PMl: 42 (89%); 2) inflammatory PMl: three (6%); and 3) JC virus GCN: four (9%). Nosocomial pneumonia (p = 0.003), previous diagnosis of HIV infection (p = 0.03), and imaging showing cerebellar and/or brainstem involvement (p = 0.02) were associated with in-hospital mortality. overall mortality during hospitalization was 34%. CONCLUSIONS: Novel presentations of JCV-associated CNS diseases were observed in our setting; nosocomial pneumonia, previous diagnosis of HIV infection, and cerebellar and/or brainstem involvement were associated with in-hospital mortality; and overall mortality was high.

Genetic parameters were estimated for objective and subjective traits assessed after 3 and 29 days aging in meat samples of 1154 commercial beef cattle. Meat attributes [Warner-Bratzler shear force (WBSF), intramuscular fat (IMF), and pH] and sensory traits [flavor intensity (FI), off-flavor (OF), connective tissue (CT), overall tenderness (OT), sustained juiciness (SJ), and overall palatability (OP)] were available. The animal mixed model used included additive genetic and residual effects as random effects, contemporary group as fixed effect and genomic breed composition and slaughter age as covariates. Genetic parameters were estimated using airemlf90 software and single-step genomic BLUP. Heritability estimates for OT (3 and 29 d), OP (3 d) and OF (29 d) were of moderate magnitude ranging from 0.18 ± 0.07 to 0.31 ± 0.07. Heritabilities were negligible or of low magnitude for all other sensory traits with values ranging from 0.03 ± 0.05 to 0.14 ± 0.07. Among objectively measured traits, the estimate of heritability for meat pH was moderate at day 3 (0.20 ± 0.08) and negligible at 29 (0.00 ± 0.05). For IMF and WBSF the heritability estimates were 0.43 ± 0.09 and 0.54 ± 0.09, and 0.22 ± 0.07 and 0.19 ± 0.07 for day 3 and 29, respectively. Genetic correlations between days for each sensory trait tended to be of high and positive magnitude ranging from 0.54 ± 0.60 to 0.99 ± 0.28. Genetic and phenotypic correlations of subjectively assessed traits were consistent in direction and magnitude with WBSF (negative) and IMF (positive) suggesting that genetic selection based on objectively measured traits can be used for meat quality improvement and to increase consumer satisfaction. In addition, selection can be implemented using sensory traits collected after 3 days of aging., Competing Interests: Declaration of Competing Interest All authors declare no conflicts of interest related to this study, and there has been no significant financial support for this work that could have influenced its outcome., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

This study identified genomic variants and underlying candidate genes related to the whole carcass and individual primal cut lean content in Canadian commercial crossbred beef cattle. Genotyping information of 1035 crossbred beef cattle were available alongside estimated and actual carcass lean meat yield and individual primal cut lean content in all carcasses. Significant fixed effects and covariates were identified and included in the animal model. Genome-wide association analysis were implemented using the weighted single-step genomic best linear unbiased prediction (WssGBLUP). A number of candidate genes identified linked to lean tissue production were unrelated to estimated lean meat yield and were specific to the actual lean traits. Among these, 41 genes were common for actual lean traits, on specific regions of BTA4, BTA13 and BTA25 indicating potential involvement in lean mass synthesis. Therefore, the results suggested the inclusion of primal cut lean traits as a selection objective in breeding programs with consideration of further functional studies of the identified genes could help in optimizing lean yield for maximal carcass value., Competing Interests: Declaration of Competing Interest None., (Crown Copyright © 2023. Published by Elsevier Ltd. All rights reserved.)

The Covid-19 outbreak has triggered a global crisis that is challenging governments, health systems and the scientific community worldwide. A central question in the Covid-19 pandemic is whether climatic factors have influenced its progression. To address this question, we used mortality rates during the first three weeks of recorded mortality in 144 countries, during the first wave of the pandemic. We examined the effect of climatic variables, along with the proportion of the population older than 64 years old, the number of beds in hospitals, and the timing and strength of the governmental travel measures to control the spread of the disease. Our first model focuses on air temperature as the central climatic factor and explains 67% of the variation in mortality rate, with 37% explained by the fixed variables considered and 31% explained by country-specific variations. We show that mortality rate is negatively influenced by warmer air temperature. Each additional Celsius degree decreases mortality rate by ~5%. Our second model is centred on the UV Index and follows the same trend as air temperature, explaining 69% of the variation in mortality rate. These results are robust to the exclusion of countries with low incomes, as well as to the exclusion of low- and medium-income countries. We also show that the proportion of vulnerable age classes and access to healthcare are critical factors impacting the mortality rate of this disease. The effects of air temperature at an early stage of the Covid-19 outbreak is a key factor to understand the primary spread of this pandemic, and should be considered in projecting subsequent waves., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2021 The Authors. Published by Elsevier B.V. All rights reserved.)

The present cohort study was set up with the aim of determining the incidence of dengue among children and adolescents, from 2 to 16 years of age, living in Araraquara, South-Eastern Brazil, a city classified as a mid-level endemicity location for dengue. Enrollment took place from September 2014 to March 2015. Baseline socio-demographic data were collected, and a blood sample from the participant was drawn, for dengue serology. Families were contacted weekly for fever surveillance. If the child developed fever, a nurse visited the household to collect a blood sample. PCR, NS1 and IgM were used for dengue diagnosis. Parents or legal guardians of participating children provided a written informed consent. 3,514 children and adolescents were enrolled in the cohort. Dengue baseline seroprevalence was 12.2% (95%CI: 11.1 - 13.3). The incidence density of symptomatic dengue was 8.94 per 100 person/years in the first year of follow-up, 0.58 in the second, and 0.19 in the fourth. No cases were confirmed in the third year. Incidence was associated with age, sex, baseline seroprevalence and with living in a house as opposed to an apartment. This study provides relevant information on the epidemiology of dengue in mid-level transmission settings that may be useful to policymakers in the evaluation of control strategies., Competing Interests: Declaration of Competing Interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: EJA Luna has received consultancy fees and travel grants form Sanofi-Pasteur. The other authors declare no potential conflicts of interest with respect to the research, authorship, and/or publication of this article., (Copyright © 2019 Elsevier B.V. All rights reserved.)

In bacteria, proteins containing GGDEF domains are involved in production of the second messenger c-di-GMP. Here we report that the cdgA gene encoding diguanylate cyclase A (CdgA) is involved in biofilm formation and exopolysaccharide (EPS) production in Azospirillum brasilense Sp7. Biofilm quantification using crystal violet staining revealed that inactivation of cdgA decreased biofilm formation. In addition, confocal laser scanning microscopy analysis of green-fluorescent protein-labeled bacteria showed that, during static growth, the biofilms had differential levels of development: bacteria harboring a cdgA mutation exhibited biofilms with considerably reduced thickness compared with those of the wild-type Sp7 strain. Moreover, DNA-specific staining and treatment with DNase I, and epifluorescence studies demonstrated that extracellular DNA and EPS are components of the biofilm matrix in Azospirillum. After expression and purification of the CdgA protein, diguanylate cyclase activity was detected. The enzymatic activity of CdgA-producing cyclic c-di-GMP was determined using GTP as a substrate and flavin adenine dinucleotide (FAD(+)) and Mg(2)(+) as cofactors. Together, our results revealed that A. brasilense possesses a functional c-di-GMP biosynthesis pathway., (Copyright © 2016 Institut Pasteur. Published by Elsevier Masson SAS. All rights reserved.)

Endovascular repair is an established modality of treatment for abdominal aortic aneurysms. It is therefore reasonable to expect its application to other less common aneurysmal conditions, including isolated iliac and popliteal artery aneurysms (PAA). There are, however, essential differences between aortic aneurysms and peripheral aneurysms: smaller arterial caliber, mobility of the arterial segment, associated occlusive disease, and devices that have not been specifically designed for peripheral applications. Due to these differences, results obtained in abdominal aortic aneurysms cannot be extrapolated to peripheral aneurysms. The attraction of the endovascular repair for PAA is its minimally invasive nature. The literature, however, provides only case reports, case series and small cohorts, and one small randomized, controlled trial. A cumulative summary of these studies provides the clinician with information upon which to base the choice of treatment on a specific patient. Endovascular repair for PAA with suitable anatomy and good run-off can be considered safe, and medium term results appear comparable with those of open repair.

Objectives: To study the risk factors and rate of progression of asymptomatic carotid stenosis in patients with peripheral arterial occlusive disease., Methods: Between July 1999 and September 2003, we studied consecutive patients referred to a vascular laboratory for peripheral arterial occlusive disease who had not experienced neurologic symptoms within the previous 3 years. Carotid duplex ultrasound scan (DUS) was performed at baseline and at 6 to 12-month intervals. The internal carotid artery peak systolic velocity (PSV) was used to determine severity of carotid stenosis. Multilevel linear regression modeling (MLM) was used to identify the rate of progression and risk factors for progression., Results: For 614 consecutive patients, median follow-up by DUS was 30 (2-42) months. Patients were 73 +/- 10-years-old, and 62% were men. Mean ankle-brachial index (ABI) was 0.79 +/- 0.24. The baseline prevalence of carotid stenosis >or=50% (PSV >or=125 cm/second) was 22%. During follow-up, ipsilateral amaurosis fugax, transient ischemic attacks, and strokes occurred in 3 (0.4%), 7 (1.1%), and 5 (0.8%) patients, respectively. Overall, there was little progression in carotid stenosis. Female gender, low ABI, and smoking were risk factors for progression of disease regardless of severity of carotid stenosis. Patients with >or=50% carotid stenosis were at greatest risk of progression if they continued smoking and were diabetic. Prediction models for progression of carotid stenosis given a baseline PSV and patient risk factors were constructed., Conclusion: There are few neurologic events in patients with asymptomatic carotid stenosis. The average rate of progression of stenosis over 2 years is not significant but greater in diabetic patients with baseline stenosis >50% who continue smoking. Rescreening by serial DUS should be limited to high-grade stenosis and follow-up performed at an interval of 1-2 years.

Objective: The objective of this study is to assess the impact of surgery on quality of life (QOL) in patients who underwent thoracoabdominal aortic aneurysm (TAAA) repair., Methods: This is a prospective single center cohort study using two quality of life questionnaires administered before surgery, at 6 months, and 1 year after surgery. The Illness Intrusiveness Rating Scale (IIRS) is a tool that on a 7-point Likert scale assesses the impact of disease on each of 13 domains of quality of life. The Karnofsky Activity Scale (KAS) uses a single rating to assess the impact on overall quality of life. At each visit, participants completed the IIRS and KAS. Healthy, nonaneurysmal individuals also completed the IIRS to form a control group., Results: From 1998 to 2006, 297 patients underwent thoracoabdominal aneurysm repair at a tertiary care hospital. Quality of life was measured on 80 patients in total. Preoperative data was available in 45 patients (7 completed the IIRS and 3 the KAS only, and 35 both); 6-month postoperative data in 25 (1 completed the KAS only, and 24 both); and 1-year data postoperative in 35 (4 completed the IIRS and 2 the KAS only, and 29 both). Internal consistency was established for IIRS (Cronbach's alpha 0.85) and KAS (0.81). The mean preoperative IIRS score was 32.10 (SD 17.91). After surgery, there was no change at the 6-month and 1-year postoperative intervals: at 6 months, the mean IIRS score was 33.17 (SD 17.66) and at 1 year the mean was 28.09 (SD 13.61). Total IIRS in nonaneurysmal controls was 13.5 (SD 0.7). The mean preoperative Karnofsky Activity Scale score was 80.0 (SD 15.07), which corresponds to an ability to perform normal activity with effort and some signs or symptoms of disease. After surgery, there was no change as patients reported a 6-month mean score of 79.60 (SD 21.89), and a 1-year postoperative mean score of 86.94 (SD 13.94)., Conclusions: Quality of life for patients undergoing TAAA repair who survive to attend follow-up in an ambulatory setting can be measured using reliable and valid instruments. Preoperatively, QOL is poor compared with healthy controls. After surgery, at 6- and 12-month follow-up, QOL seems to return to the preoperative levels. Further research is necessary to address responsiveness and sensitivity of QOL measuring tools.

Objectives: The perioperative mortality for people with ruptured abdominal aortic aneurysms (RAAA) has not changed for two decades. Of patients who survive long enough to undergo open repair for ruptured aneurysms, half die (48%; 95% confidence interval [CI] 46 to 50). Randomized trials have shown that endovascular aneurysm repair (EVAR) for nonruptured abdominal aortic aneurysms decreases perioperative mortality compared with open repair. EVAR may similarly benefit patients with RAAA. We aimed to summarize studies of patients undergoing EVAR for ruptured aneurysms., Methods: Two reviewers searched Medline and EMBASE databases from 1994 to July 2006, Cochrane Database of Systematic Reviews, the Database of Abstracts of Reviews of Effectiveness, the Cochrane Central Register of Controlled Trials, Best Evidence 1994 to 2006, reference lists, clinical trial registries, and conference proceedings; we also contacted authors. All published and unpublished studies in which a group of people with ruptured aneurysms, assessed objectively by imaging, was treated with EVAR (REVAR) were eligible. We used the generic inverse variance function of the REVMAN software to pool results for death in hospital. Sensitivity analyses, using prespecified subgroups, explored heterogeneity between studies., Results: Pooled mortality in 18 observational studies describing 436 people who underwent REVAR was 21% (95% CI 13 to 29); however, 90% of the heterogeneity between studies was not explained by chance alone. Surgical volume explained substantial heterogeneity. According to study-specific criteria, 47% (95% CI 39 to 55) of people with ruptured aneurysms were potentially eligible for REVAR., Conclusions: Mortality in people who underwent REVAR is lower than that in historical reports of unselected people undergoing open repair. Further investigation is needed to determine whether the difference in mortality is attributable to patient selection alone or to this new approach to treatment.

Background: The study was conducted to demonstrate improved survival (30-day mortality) after the introduction of an emergency endovascular therapy protocol for ruptured abdominal aortic aneurysms (rAAA). Numerous authors have successfully demonstrated reduced mortality in patients with rAAA using endovascular techniques. Comparison of endovascular aneurysm repair (EVAR) with open repair for rAAA may be misleading, however, because EVAR cannot be performed on all patients, and selection bias may explain the superior performance of any given surgical or endovascular strategy. We developed a model to predict mortality in patients before the introduction of EVAR (preprotocol population), applied this model to predict 30-day mortality among prospective patients (postprotocol population), and compared observed vs expected results., Methods: We assessed 126 patients with rAAA. Primary outcome was 30-day mortality. Potential confounding variables were age, sex, presurgical lowest recorded systolic blood pressure (SBP), and glomerular filtration rate (GFR). A logistic regression model incorporating significant confounders was used to evaluate changes in 30-day mortality for all patients with rAAA after introduction of the EVAR protocol. Separate logistic regressions were done to compare 30-day mortality for preprotocol vs patients receiving EVAR and preprotocol vs patients receiving postprotocol open repair. Cumulative sum (CUSUM) analysis was used to assess shifts in the performance of the rAAA program over time., Results: Significant confounders were SBP, absence of SBP, and GFR. Logistic regression found evidence of lower mortality after the protocol was introduced, 17.9% vs 30.0% (odds ratio [OR], 0.385; 95% confidence interval [CI], 0.141 to 0.981; P = .046). Comparison of all open repairs (preprotocol and postprotocol) and EVAR demonstrated decreased risk for EVAR of 5.0% vs 28.3% (OR, 0.109; 95% CI, 0.013 to 0.906; P = .0084). Unstable patients (SBP

The low spin states of microperoxidases (MP)-8, -9 and -9 N-acetylated (N-Ac) were characterized using UV-visible, circular dichroism, and electron paramagnetic resonance spectroscopies over the 6.0-12.0 pH range. The first MP-8 alkaline transition (pK(a)=8.53) produced hemepeptide aggregates in the low spin state in which a water molecule was replaced by the peptide chain N-terminal group of a neighboring MP-8 molecule. Higher pH led to the deprotonation of the MP-8 histidine imidazole ring (pK(a)=10.37) at the fifth coordination position. This MP-8 species was in equilibrium with a high spin state aggregate in which OH(-) replaced histidinate, the histidinate becoming the heme iron sixth ligand in a neighboring MP-8 molecule. In a similar way to the N-AcMP-8, the low spin state of N-AcMP-9 was produced by the deprotonation of the water molecule (pK(a)=9.6) situated at the sixth coordination position of the heme iron. Up to pH 8.5, the low spin states of MP-9 were aggregates in which the alpha-amino group of Lys13 replaced water at the sixth coordination position of a neighboring MP-9 molecule. Above pH 8.5, the epsilon-amino groups of Lys13 established intra-chain coordination and impaired the formation of aggregates. Such intra-chain interaction in MP9 was supported by molecular dynamics simulation. These MP-9 monomers might also exhibit OH(-) or histidinate at the fifth coordination position.

Background: Duplex ultrasound is widely used for the diagnosis of internal carotid artery stenosis. Standard duplex ultrasound criteria for the grading of internal carotid artery stenosis do not exist; thus, we conducted a systematic review and meta-analysis of the relation between the degree of internal carotid artery stenosis by duplex ultrasound criteria and degree of stenosis by angiography., Methods: Data were gathered from Medline from January 1966 to January 2003, the Cochrane Central Register of Controlled Trials and Database of Systematic Reviews, Database of Abstracts of Reviews of Effects, ACP Journal Club, UpToDate, reference lists, and authors' files. Inclusion criteria were the comparison of color duplex ultrasound results with angiography by the North American Symptomatic Carotid Endarterectomy Trial method; peer-reviewed publications, and >/=10 adults., Results: Variables extracted included internal carotid artery peak systolic velocity, internal carotid artery end diastolic velocity, internal carotid artery/common carotid artery peak systolic velocity ratio, sensitivity and specificity of duplex ultrasound scanning for internal carotid artery stenosis by angiography. The Standards for Reporting of Diagnostic Accuracy (STARD) criteria were used to assess study quality. Sensitivity and specificity for duplex ultrasound criteria were combined as weighted means by using a random effects model. The threshold of peak systolic velocity >/=130 cm/s is associated with sensitivity of 98% (95% confidence intervals [CI], 97% to 100%) and specificity of 88% (95% CI, 76% to 100%) in the identification of angiographic stenosis of >/=50%. For the diagnosis of angiographic stenosis of >/=70%, a peak systolic velocity >/=200 cm/s has a sensitivity of 90% (95% CI, 84% to 94%) and a specificity of 94% (95% CI, 88% to 97%). For each duplex ultrasound threshold, measurement properties vary widely between laboratories, and the magnitude of the variation is clinically important. The heterogeneity observed in the measurement properties of duplex ultrasound may be caused by differences in patients, study design, equipment, techniques or training., Conclusions: Clinicians need to be aware of the limitations of duplex ultrasound scanning when making management decisions.

Objectives: We undertook a quantitative systematic review of randomized controlled trials (RCTs) and observational studies to determine the effectiveness of cerebrospinal fluid (CSF) drainage to prevent paraplegia in thoracic aneurysm (TA) and thoracoabdominal aortic aneurysm (TAAA) surgery., Methods: We included RCTs and cohort studies that met the following criteria: elective or emergent aneurysm surgery involving the thoracic or thoracoabdominal aorta, documentation of postoperative neurologic deficits, and patient age older than 18 years. We excluded studies that reported results in 10 or fewer patients and duplicate publications. We identified eligible studies by searching computerized databases, our own files, and the reference lists of relevant articles and review articles. Database searching, eligibility decisions, relevance and method quality assessments, and data extraction were performed in duplicate with prespecified criteria., Results: Of 372 publications identified in our search, 14 met our eligibility criteria. Three RCTs reported 289 patients with type I or type II TAAA. Lower limb neurologic deficits occurred in 12% of patients who underwent CSF drainage and 33% of control subjects (number needed to treat, 9; 95% confidence interval [CI], 5-50). The pooled odds ratio (OR) for development of paraplegia in patients in the CSF drainage group was 0.35 (P =.05; 95% CI, 0.12-0.99). Similar results were found in five cohort studies with a control group (pooled OR, 0.26; P =.0002; 95% CI, 0.13-0.53). When all studies were considered together the pooled OR of TA and TAAA was 0.3 (95% CI, 0.17-0.54). There was no statistical heterogeneity among studies included in the meta-analysis. In six cohort studies without a control group, the incidence of paraplegia in high-risk TA and TAAA was 7.6%., Conclusions: Evidence from randomized and nonrandomized trials and from cohort studies support the use of CSF drainage as an adjunct to prevent paraplegia when this adjunct is used in centers with large experience in the management of TAAA.

Between October 1990 and June 2001, 121 patients underwent surgery for thoracoabdominal aortic aneurysm (TAAA)-99 procedures were elective and 22 were for ruptured aneurysms. Between October 1990 and September 1997, the clamp-and-go technique was used for all aneurysms (43 patients), and from October 1997, clamp-and-go was reserved for type IV TAAAs, and atriofemoral bypass (AFB) was used for types I, II, and III (78 patients). Overall hospital mortality was 21.4% (26/121)-12% for the elective group and 64% for the ruptured group. Hospital mortality was associated with age (67 years in survivors vs. 73 years in nonsurvivors, p = 0.03), FEV1<2 L (RR 4.1, p = 0.01), CSF drainage (RR 5.0, p = 0.03), type II aneurysms vs. other aneurysms (RR 3.7, p = 0.02), and relative inexperience (mean rank in the series was 52 in survivors vs. 30 in nonsurvivors, p = 0.01). The overall incidence of neurologic deficits due to spinal cord ischemia was 6.2% (paraplegia in 4.4%). Temporary dialysis was necessary in 13% of patients, and chronic dialysis in 2%. In long-term follow-up of patients undergoing elective repair, 5-year survival was 80% and median survival was 7.9 years. Mortality and neurologic deficits have improved over time as a consequence of either increased surgical experience, the adoption of a protocolized strategy for repair, or secular improvements in ICU care. Long-term survival after elective TAAA repair is excellent.

Purpose: We describe outcomes in a cohort of patients undergoing subclavian carotid transposition (SCT) for occlusive disease of the first segment of the subclavian artery and perform a systematic review of the literature on SCT and carotid subclavian bypass grafting (CSB)., Methods: Relevance, validity and extraction of review results were done in duplicate. Data were collected prospectively in our consecutive cohort of patients., Results: From September 1990 to February 2001, we performed 27 SCTs, four for aneurysmal disease and 23 for occlusive disease. SCTs done for aneurysms were excluded from the current analysis. In patients with occlusive disease, the primary indications for surgery were vertebrobasilar and carotid symptoms (10, 44%), vertebrobasilar insufficiency (7, 30%), vertebrobasilar and arm symptoms (4, 17%), carotid symptoms (1, 4%), and vertebrobasilar, carotid, and arm symptoms (1, 4%). An SCT was performed in conjunction with an endarterectomy of the carotid artery in 12 patients (52%), with an endarterectomy of the subclavian artery in seven patients (30%), and with an endarterectomy of the vertebral artery in six patients (26%). A lymph leak complicated two surgeries (9%). In our series, patients improved clinically after surgery, and reconstructions were all found to be patent by means of Doppler ultrasound scanning at a mean follow-up of 25 +/- 21 months. Three patients (13%) died during follow-up of complications of coronary artery disease. From 1966 to 2000, 516 patients who underwent CSB and 511 patients who underwent a SCT were reported in the literature. Patency rates were 84% and 98%, respectively (P <.0001; absolute risk reduction, 15%; number-needed-to-treat-differently, 7), and the rates of freedom from symptoms were 88% and 99%, respectively, at a mean follow-up of 59 +/- 17 months (range, 1-228 months)., Conclusion: Our cohort study showed that SCT is safe and effective for reconstruction of the first segment of the subclavian artery. The systematic review suggested that rates of patency and freedom from clinical symptoms are higher with SCT than with CSB.