Diversidad de ninfas de Leptohyphidae (Ephemeroptera) en el río Quenane-Quenanito, piedemonte llanero colombiano / Diversity of Leptohyphidae (Ephemeroptera) nymphs in the Quenane-Quenanito river, Colombian plain foothills

Resumen Introducción: Varias presiones antrópicas sufren los ecosistemas acuáticos del piedemonte llanero en Colombia. La respuesta a estresores ambientales aún se desconoce en organismos bioindicadores como Leptohyphidae. Objetivo: Determinar la diversidad de ninfas de Leptohyphidae del río Quenane-Quenanito, en dos periodos hidrológicos contrastantes y su relación con algunas variables fisicoquímicas. Métodos: En diciembre (2014) y febrero (2015) se recolectaron organismos con red Surber en seis estaciones a lo largo del río. Se analizó la diversidad alfa y beta y se aplicó análisis de redundancia y modelos lineales generalizados con el fin de establecer la relación entre los taxones y las variables ambientales. Resultados: Se identificaron 369 organismos pertenecientes a cuatro géneros (Amanahyphes, Traverhyphes, Tricorythopsis y Tricorythodes), dos especies y ocho morfoespecies. Se reporta por primera vez para el departamento del Meta Amanahyphes saguassu. Se registró la mayor diversidad de ninfas en la transición a la sequía y la mayor abundancia en sequía. La diversidad beta señaló que la configuración del ensamblaje cambia a nivel espacial y temporal. Conclusiones: Los organismos de Leptohyphidae prefieren hábitats de corrientes, particularmente en el periodo de sequía, donde hallan alimento (hojarasca, detritos) y refugio para establecerse exitosamente; actividades antrópicas como la urbanización afectan notablemente la diversidad. La alta diversidad registrada en este pequeño río de piedemonte llanero refleja la necesidad de incrementar este tipo de trabajos y esfuerzos de recolección de material de estudio en la región.

Abstract Introduction: Various anthropic pressures affect the aquatic ecosystems of the foothills of Colombia. The response to environmental stressors is still unknown in bioindicator organisms such as Leptohyphidae. Objective: To determine the diversity of Leptohyphidae nymphs of the Quenane-Quenanito river, in two contrasting hydrological periods and its relationship with some physicochemical variables. Methods: In December (2014) and February (2015), organisms were collected with a Surber net at six stations along the current. Alpha and beta diversity was analyzed and redundancy analysis and generalized linear model were applied to establish the relationship between taxa and environmental variables. Results: Were identified 369 organisms belonging to four genera (Amanahyphes, Traverhyphes, Tricorythopsis, and Tricorythodes), two species, and eight morphospecies. Amanahyphes saguassu is reported for the first time for the Meta department. High diversity of Leptohyphidae nymphs was recorded in the transition to drought season and greater abundance in drought. Beta diversity indicated that the configuration of the assemblage changes spatially and temporally. Conclusions: Leptohyphidae organisms prefer fast habitats, particularly in the dry period where they find food (leaf litter, detritus) and shelter to establish themselves successfully; anthropic activities such as urbanization notably affect diversity. The high diversity recorded in this small river in the foothills of the plains reflects the need to increase this type of works and collection efforts of study material in the region.

The synthetic molecule stauprimide impairs cell growth and migration in triple-negative breast cancer.

Stauprimide, a semi-synthetic derivative of staurosporine, is known mainly for its potent differentiation-enhancing properties in embryonic stem cells. Here, we studied the effects of stauprimide in cell growth and migration of triple-negative breast cancer cells in vitro, evaluating its potential antitumoral activity in an orthotopic mouse model of breast cancer in vivo. Our results from survival curves, EdU incorporation, cell cycle analysis and annexin-V detection in MDA-MB-231 cells indicated that stauprimide inhibited cell proliferation, arresting cell cycle in G2/M without induction of apoptosis. A decrease in the migratory capability of MDA-MB-231 was also assessed in response to stauprimide. In this work we pointed to a mechanism of action of stauprimide involving the modulation of ERK1/2, Akt and p38 MAPK signalling pathways, and the downregulation of MYC in MDA-MB-231 cells. In addition, orthotopic MDA-MB-231 xenograft and 4T1 syngeneic models suggested an effect of stauprimide in vivo, increasing the necrotic core of tumors and reducing metastasis in lung and liver of mice. Together, our results point to the promising role of stauprimide as a putative therapeutic agent in triple-negative breast cancer.

Color Doppler Sonography Assisted Subcutaneous Mastectomy with Inferior Pedicled Nipple-Areola Complex in Female-to-Male Transsexuals: A Retrospective Cohort Analysis.

BACKGROUND: The surgical goals of gender reassignment surgery of the breast in female-to male transsexuals (FMT) is the aesthetic shaping of a male thoracic wall with minimal scarring, while preserving the sensitivity of the nipple-areola complex (NAC). For large and ptotic breasts, we perform a mastectomy over an inframammary access with inferior pedicled NAC under color Doppler visualization of the perforators. This paper presents the technique, including complications and assessment of quality of life, as part of a unicentric analysis. METHODS: This was a retrospective analysis of 23 patients (46 mastectomies) performed between September 2014 and September 2020. The complication rate and the number of corrective surgeries were recorded for quality assessment. A semiquantitative score was used to evaluate aesthetic outcome, nipple sensitivity, quality of life, and sexuality. RESULTS: A total of 46 mastectomies were performed in 23 patients. The patient survey showed high patient satisfaction. Loss of nipple sensitivity was observed after one mastectomy (2.17%). In 91.67% of cases, patients reported that their appearance reflected how they feel on the inside. In 75% of cases, patients reported feeling equal to other men. The overall complication rate was 10.87%. Shape correction due to persistent excess of volume was rare (2.17%, equivalent to one mastectomy). CONCLUSION: Subcutaneous mastectomy with inferior nipple pedicle can be performed with a high degree of safety and satisfaction in FMT. Color Doppler-guided visualization of the perforator vessels is helpful in allowing a thin pedicle preparation, thus reducing the need for secondary surgeries to optimize the shape. LEVEL OF EVIDENCE IV: This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Simultaneous correction of a pectus excavatum with tubular breast deformity using a custom-made silicone implant.

Pectus excavatum (PE) is one of the most common congenital deformities of the thorax and is characterized by a depressed sternum with reduction of the antero-posterior thoracic diameter. Although the majority of patients with PE have no physiologic limitations, it is often associated with psychological problems influencing the patients' quality of life. Surgical treatment options show particular variation with regard to invasiveness and morbidity of the respective procedures. Surgical treatment using a custom-made silicone implant represents a less invasive alternative for patients without further accompanying physical symptoms. This article describes the simultaneous correction of a PE combined with tubular breast deformity using this minimally invasive technique.

Hypervirulent and hypermucoviscous extended-spectrum ß-lactamase-producing Klebsiella pneumoniae and Klebsiella variicola in Chile.

Convergence of virulence and antibiotic-resistance has been reported in Klebsiella pneumoniae, but not in Klebsiella variicola. We, hereby, report the detection and genomic characterization of hypervirulent and hypermucoviscous K. pneumoniae and K.variicola recovered in Chile from health-care associated infections, which displayed resistance to broad-spectrum cephalosporins. One hundred forty-six K. pneumoniae complex isolates were screened by hypermucoviscosity by the "string test." Two hypermucoid isolates, one hypermucoviscous K. pneumoniae (hmKp) and one K. variicola (hmKv), were further investigated by whole-genome sequencing. In vivo virulence was analyzed by the Galleria mellonella killing assay. In silico analysis of hmKp UCO-494 and hmKv UCO-495 revealed the presence of multiple antibiotic-resistance genes, such as blaCTX-M-1, blaDHA-1 and blaLEN-25 among others clinically relevant resistance determinants, including mutations in a two-component regulatory system related to colistin resistance. These genetic features confer a multidrug-resistant (MDR) phenotype in both strains. Moreover, virulome in silico analysis confirmed the presence of the aerobactin gene iutA, in addition to yersiniabactin and/or colicin V encoding genes, which are normally associated to high virulence in humans. Furthermore, both isolates were able to kill G. mellonella and displayed higher virulence in comparison with the control strain. In summary, the convergence of virulence and the MDR-phenotype in K. pneumoniae complex members is reported for the first time in Chile, denoting a clinical problem that deserves special attention and continuous surveillance in South America.

A scenario-based analysis of the effect of carbon pricing on organic livestock farm performance: A case study of Spanish dehesas and rangelands.

The current livestock farm production model is being questioned due to its excessive use of resources and impacts on the environment, and it has played a major role in climate change due to the excessive level of greenhouse gas (GHG) emissions. A valid tool in the reduction of such emissions is the imposition of a tax on CO2 emissions that can act as an economic and financial instrument. Additionally, livestock production based on grazing animals is proposed as a more sustainable model that involves improved environmental practices and provides society with various ecosystem services, including carbon sequestration. The main purpose of this paper is to estimate the maximum price per tonne of CO2 equivalent (eq) that could be borne by the various models of organic livestock farms in the dehesas and rangelands of southwestern Spain. With this purpose in mind, we have made a scenario-based estimation of the environmental-economic balance in three different scenarios considering farm emissions and CO2 sequestration levels. The results show that the maximum price that farms can bear is within a range of € 0.20 to € 792/tn of CO2 eq depending on the scenario analysed and the production model. In the cases in which carbon sequestration balances GHG emissions, the implementation of carbon pricing implies additional economic income for farm accounts.

Mass Transfer and Colour Analysis during Vacuum Frying of Colombian Coastal Carimañola.

This study is aimed at analysing the effect of vacuum frying on the kinetic parameters of mass transfer, the CIE L ∗ a ∗ b ∗ colour parameters of the Carimañola. For the kinetic analysis, the moisture and oil content were measured by means of an experimental design consisting of two factors: frying time with seven levels (60, 120, 180, 240, 300, 420, and 540 s) and frying temperature with three levels (120, 130, and 140°C). The diffusivity coefficient, the moisture transfer rate, and the oil adsorption rate, with their respective activation energies, were calculated. For the colour analysis, the reflectance technique was used to determine the colour coordinates of the CIE L ∗ a ∗ b ∗ space, and the general colour change was calculated (ΔE). Concerning the kinetics, the increase in temperature and frying time reduced the moisture content, while the oil content decreased with the increase in temperature and increases with frying time. The diffusivity ranged from 1, 238 × 10-6 m2/s at 120°C to 2, 84 × 10-6 m2/s at 140°C. The mass transfer coefficients for moisture ranged from 2 × 10-4 m/s at 120°C to 4 × 10-4 m/s at 140°C. The values of the oil uptake rate were from 0.0022 s-1 at 120°C to 0.0018 s-1 at 140°C. Finally, the luminosity parameter shows a decrease with the increase in temperature, although the first 240 s shows a rise and then begins to decrease. Vacuum frying allowed Carimañolas to be obtained with a lower oil and moisture content, with an appropriate colouring, eye-catching and visually attractive to consumers.

Is production system a relevant attribute in consumers' food preferences? The case of Iberian dry-cured ham in Spain.

Spanish consumers have a strong preference for Iberian meat products, as they perceive them to be of extra sensorial and nutritional quality. The production of these meat products depends on multiple variables, such as genetics, livestock production systems and, above all, the feed provided. The aim of this paper is to study the preferences of Spanish consumers for the various types of Iberian dry-cured ham, analysing whether they are willing to pay the premium required by the highest-quality products. The methodological approach combined a sensory analysis and a choice-based conjoint experiment with obtained through tasting sessions in Extremadura (SW of Spain). Findings of the sensory test have shown that there are significant differences in odour, texture and taste, explained mainly by the type of feed pigs were fed. The main results of the choice experiment have also shown that the type of feed is the most preferred attribute by consumers, in line with the sensory analysis.

Concurrent Daily Cisplatin and High-Dose Radiation Therapy in Patients With Stage III Non-Small Cell Lung Cancer.

PURPOSE: The purpose of this study was to determine survival, local and distant control, toxicity, and prognostic factors in patients with stage III non-small cell lung cancer (NSCLC) treated with concurrent chemoradiation therapy (CCRT). METHODS AND MATERIALS: Consecutive patients with stage IIIA and IIIB NSCLC (N = 154) staged with 18F-fluorodeoxyglucose positron emission tomography/computed tomography were retrospectively selected (2005-2015). CCRT consisted of daily low-dose cisplatin (6 mg/m2) combined with 24 fractions of 2.75 Gy to a total dose of 66 Gy. RESULTS: During a median follow-up period of 22 months (range, 1-92 months) the median overall survival was 36 months. The 1-, 2-, 3-, and 5-year survival rates were 79% (95% confidence interval [CI], 73%-86%), 61% (95% CI, 54%-70%), 52% (95% CI, 43%-60%), and 40% (95% CI, 31%-51%), respectively. The local relapse-free survival at 5 years was 55% (95% CI, 44%-69%). Metastasis-free survival at 5 years was 53% (95% CI, 44%-65%). The incidence of severe gastrointestinal disorders (grade 3-5) was 11%, among which grade 3 radiation esophagitis was 8.4%. The incidence of severe respiratory, thoracic, and mediastinal disorders (grade 3-5) was 8.4%, among which grade 3 radiation pneumonitis was 1.3%. Predictors of overall survival were lymph node gross tumor volume (GTV) (hazard ratio [HR], 1.007; 95% CI, 1.000-1.012) and sex (HR, 0.500; 95% CI, 0.320-0.870) in favor of women. Although lymph node GTV was a predictor of treatment toxicity (HR, 1.010; 95% CI, 1.000-1.013), tumor GTV was the predictor for distant metastasis during follow-up (HR, 1.002; 95% CI, 1.001-1.003). CONCLUSIONS: CCRT with daily low-dose cisplatin for locally advanced stage III NSCLC resulted in promising overall survival (3-year survival rate of 52% and 5-year survival rate of 40%) with low toxicity. Lymph node GTV, tumor GTV, and sex were predictors of overall survival, treatment toxicity, and distant metastasis.

A participative approach to develop sustainability indicators for dehesa agroforestry farms.

This paper provides a list of specific indicators that will allow the managers of dehesa farms to assess their sustainability in an easy and reliable way. To this end a Delphi analysis has been carried out with a group of experts in agroforestry systems and sustainability. A total of 30 experts from public institutions, farming, research bodies, environmental and rural development associations, agricultural organizations and companies took part in the study which intended to design a set of sustainability indicators adapted to dehesa agroforestry systems. The experts scored 83 original indicators related to the basic pillars of sustainability (environmental, social and economic) through a two-round procedure. Finally, 24 indicators were selected based on their importance and the consensus achieved. From an environmental point of view, and in line with its significance for dehesa ecosystems, it has been observed that "Stocking rate" is the indicator with greater relevance. Within the economic pillar, "Farm profitability" is the most important indicator, while regarding the technical indicators "Percentage of animal diet based on grazing" is the one that got the highest score. Finally, the "Degree of job satisfaction" and the "Generational renewal" were the most relevant labor indicators. It is considered that the Delphi approach used in this research settles some of the flaws of other sustainability models, such as the adaptation to the system to be studied and the involvement of stakeholders in the design.

The Effect of Arterial Curvature on Blood Flow in Arterio-Venous Fistulae: Realistic Geometries and Pulsatile Flow.

Arterio-Venous Fistulae (AVF) are regarded as the "gold standard" method of vascular access for patients with End-Stage Renal Disease (ESRD) who require haemodialysis. However, up to 60% of AVF do not mature, and hence fail, as a result of Intimal Hyperplasia (IH). Unphysiological flow and oxygen transport patterns, associated with the unnatural and often complex geometries of AVF, are believed to be implicated in the development of IH. Previous studies have investigated the effect of arterial curvature on blood flow in AVF using idealized planar AVF configurations and non-pulsatile inflow conditions. The present study takes an important step forwards by extending this work to more realistic non-planar brachiocephalic AVF configurations with pulsatile inflow conditions. Results show that forming an AVF by connecting a vein onto the outer curvature of an arterial bend does not, necessarily, suppress unsteady flow in the artery. This finding is converse to results from a previous more idealized study. However, results also show that forming an AVF by connecting a vein onto the inner curvature of an arterial bend can suppress exposure to regions of low wall shear stress and hypoxia in the artery. This finding is in agreement with results from a previous more idealized study. Finally, results show that forming an AVF by connecting a vein onto the inner curvature of an arterial bend can significantly reduce exposure to high WSS in the vein. The results are important, as they demonstrate that in realistic scenarios arterial curvature can be leveraged to reduce exposure to excessively low/high levels of WSS and regions of hypoxia in AVF. This may in turn reduce rates of IH and hence AVF failure.

Quantitative Thermal Testing Profiles as a Predictor of Treatment Response to Topical Capsaicin in Patients with Localized Neuropathic Pain.

There are no reliable predictors of response to treatment with capsaicin. Given that capsaicin application causes heat sensation, differences in quantitative thermal testing (QTT) profiles may predict treatment response. The aim of this study was to determine whether different QTT profiles could predict treatment outcomes in patients with localized peripheral neuropathic pain (PeLNP). We obtained from medical records QTT results and treatment outcomes of 55 patients treated between 2010 and 2013. Warm sensation threshold (WST) and heat pain threshold (HPT) values were assessed at baseline at the treatment site and in the asymptomatic, contralateral area. Responders were defined as those who achieved a > 30% decrease in pain lasting > 30 days. Two distinct groups were identified based on differences in QTT profiles. Most patients (27/31; 87.1%) with a homogenous profile were nonresponders. By contrast, more than half of the patients (13/24, 54.2%) with a nonhomogenous profile were responders (p = 0.0028). A nonhomogenous QTT profile appears to be predictive of response to capsaicin. We hypothesize patients with a partial loss of cutaneous nerve fibers or receptors are more likely to respond. By contrast, when severe nerve damage or normal cutaneous sensations are present, the pain is likely due to central sensitization and thus not responsive to capsaicin. Prospective studies with larger patient samples are needed to confirm this hypothesis.

Risk of Symptomatic Stroke After Radiation Therapy for Childhood Cancer: A Long-Term Follow-Up Cohort Analysis.

PURPOSE: Long-term childhood cancer survivors are at high risk of late adverse effects, including stroke. We aimed to determine the cumulative incidence of clinically validated symptomatic stroke (transient ischemic attack [TIA], cerebral infarction, and intracerebral hemorrhage [ICH]) and to quantify dose-effect relationships for cranial radiation therapy (CRT) and supradiaphragmatic radiation therapy (SDRT). METHODS AND MATERIALS: Our single-center study cohort included 1362 survivors of childhood cancer that were diagnosed between 1966 and 1996. Prescribed CRT and SDRT doses were converted into the equivalent dose in 2-Gy fractions (EQD2). Multivariate Cox regression models were used to analyze the relationship between the EQD2 and stroke. RESULTS: After a median latency time of 24.9 years and at a median age of 31.2 years, 28 survivors had experienced a first stroke: TIA (n=5), infarction (n=13), and ICH (n=10). At an attained age of 45 years, the estimated cumulative incidences, with death as competing risk, among survivors treated with CRT only, SDRT only, both CRT and SDRT, and neither CRT nor SDRT were, respectively, 10.0% (95% confidence interval [CI], 2.5%-17.0%), 5.4% (95% CI, 0%-17.0%), 12.5% (95% CI, 5.5%-18.9%), and 0.1% (95% CI, 0%-0.4%). Radiation at both locations significantly increased the risk of stroke in a dose-dependent manner (hazard ratios: HRCRT 1.02 Gy(-1); 95% CI, 1.01-1.03, and HRSDRT 1.04 Gy(-1); 95% CI, 1.02-1.05). CONCLUSIONS: Childhood cancer survivors treated with CRT, SDRT, or both have a high stroke risk. One in 8 survivors treated at both locations will have experienced a symptomatic stroke at an attained age of 45 years. Further research on the pathophysiologic processes involved in stroke in this specific group of patients is needed to enable the development of tailored secondary prevention strategies.

Using a retrospective pretest instead of a conventional pretest is replacing biases: a qualitative study of cognitive processes underlying responses to thentest items.

BACKGROUND: The thentest design aims to detect and control for recalibration response shift. This design assumes (1) more consistency in the content of the cognitive processes underlying patients' quality of life (QoL) between posttest and thentest assessments than between posttest and pretest assessments; and (2) consistency in the time frame and description of functioning referenced at pretest and thentest. Our objective is to utilize cognitive interviewing to qualitatively examine both assumptions. METHODS: We conducted think-aloud interviews with 24 patients with cancer prior to and after radiotherapy to elicit cognitive processes underlying their assessment of seven EORTC QLQ-C30 items at pretest, posttest and thentest. We used an analytic scheme based on the cognitive process models of Tourangeau et al. and Rapkin and Schwartz that yielded five cognitive processes. We subsequently used this input for quantitative analysis of count data. RESULTS: Contrary to expectation, the number of dissimilar cognitive processes between posttest and thentest was generally larger than between pretest and posttest across patients. Further, patients considered a range of time frames when answering the thentest questions. Moreover, patients' description at the thentest of their pretest functioning was often not similar to that which was noted at pretest. Items referring to trouble taking a short walk, overall health and QoL were most often violating the assumptions. CONCLUSIONS: Both assumptions underlying the thentest design appear not to be supported by the patients' cognitive processes. Replacing the conventional pretest-posttest design with the thentest design may simply be replacing one set of biases with another.

Alginate-hyaluronan composite hydrogels accelerate wound healing process.

In this paper we propose polysaccharide hydrogels combining alginate (ALG) and hyaluronan (HA) as biofunctional platform for dermal wound repair. Hydrogels produced by internal gelation were homogeneous and easy to handle. Rheological evaluation of gelation kinetics of ALG/HA mixtures at different ratios allowed understanding the HA effect on ALG cross-linking process. Disk-shaped hydrogels, at different ALG/HA ratio, were characterized for morphology, homogeneity and mechanical properties. Results suggest that, although the presence of HA does significantly slow down gelation kinetics, the concentration of cross-links reached at the end of gelation is scarcely affected. The in vitro activity of ALG/HA dressings was tested on adipose derived multipotent adult stem cells (Ad-MSC) and an immortalized keratinocyte cell line (HaCaT). Hydrogels did not interfere with cell viability in both cells lines, but significantly promoted gap closure in a scratch assay at early (1 day) and late (5 days) stages as compared to hydrogels made of ALG alone (p<0.01 and 0.001 for Ad-MSC and HaCaT, respectively). In vivo wound healing studies, conducted on a rat model of excised wound indicated that after 5 days ALG/HA hydrogels significantly promoted wound closure as compared to ALG ones (p<0.001). Overall results demonstrate that the integration of HA in a physically cross-linked ALG hydrogel can be a versatile strategy to promote wound healing that can be easily translated in a clinical setting.

Combining Mitomycin C and Regional 70 MHz Hyperthermia in Patients with Nonmuscle Invasive Bladder Cancer: A Pilot Study.

PURPOSE: Despite intravesical therapy with immunotherapy or chemotherapy intermediate and high risk nonmuscle invasive bladder cancer is associated with a high risk of recurrence and progression to muscle invasive bladder carcinoma. While intravesical hyperthermia combined with mitomycin C has proved effective to treat nonmuscle invasive bladder cancer, there is less experience with invasive regional 70 MHz hyperthermia and mitomycin C. Therefore, we examined the safety and feasibility of this treatment combination for intermediate and high risk nonmuscle invasive bladder cancer. MATERIALS AND METHODS: Between 2009 and 2011, 20 patients with intermediate and high risk nonmuscle invasive bladder cancer were treated with intravesical mitomycin C (40 mg) combined with regional hyperthermia. Treatment consisted of 6 weekly sessions followed by a maintenance period of 1 year with 1 hyperthermia-mitomycin C session every 3 months. Regional hyperthermia was administered using a 70 MHz phased array system with 4 antennas. Toxicity was scored using CTC (Common Toxicity Criteria) 3.0. RESULTS: The records of 18 of 20 patients could be analyzed. Median followup was 46 months. Of the 18 patients 15 (83%) completed the induction period of 6 treatments. Four patients (22%) discontinued treatment because of physical complaints without exceeding grade 2 toxicity. Toxicity scored according to CTC 3.0 was limited to grade 1 in 43% of cases and grade 2 in 14%. Mean T90 and T50 bladder temperatures were 40.6C and 41.6C, respectively. The 24-month recurrence-free survival rate was 78%. CONCLUSIONS: Treatment with regional hyperthermia combined with mitomycin C in patients with intermediate and high risk nonmuscle invasive bladder cancer is feasible with low toxicity and excellent bladder temperatures.

The effect of in-plane arterial curvature on blood flow and oxygen transport in arterio-venous fistulae.

Arterio-Venous Fistulae (AVF) are the preferred method of vascular access for patients with end stage renal disease who need hemodialysis. In this study, simulations of blood flow and oxygen transport were undertaken in various idealized AVF configurations. The objective of the study was to understand how arterial curvature affects blood flow and oxygen transport patterns within AVF, with a focus on how curvature alters metrics known to correlate with vascular pathology such as Intimal Hyperplasia (IH). If one subscribes to the hypothesis that unsteady flow causes IH within AVF, then the results suggest that in order to avoid IH, AVF should be formed via a vein graft onto the outer-curvature of a curved artery. However, if one subscribes to the hypothesis that low wall shear stress and/or low lumen-to-wall oxygen flux (leading to wall hypoxia) cause IH within AVF, then the results suggest that in order to avoid IH, AVF should be formed via a vein graft onto a straight artery, or the inner-curvature of a curved artery. We note that the recommendations are incompatible-highlighting the importance of ascertaining the exact mechanisms underlying development of IH in AVF. Nonetheless, the results clearly illustrate the important role played by arterial curvature in determining AVF hemodynamics, which to our knowledge has been overlooked in all previous studies.

Valvular abnormalities detected by echocardiography in 5-year survivors of childhood cancer: a long-term follow-up study.

PURPOSE: To determine the prevalence of valvular abnormalities after radiation therapy involving the heart region and/or treatment with anthracyclines and to identify associated risk factors in a large cohort of 5-year childhood cancer survivors (CCS). METHODS AND MATERIALS: The study cohort consisted of all 626 eligible 5-year CCS diagnosed with childhood cancer in the Emma Children's Hospital/Academic Medical Center between 1966 and 1996 and treated with radiation therapy involving the heart region and/or anthracyclines. We determined the presence of valvular abnormalities according to echocardiograms. Physical radiation dose was converted into the equivalent dose in 2-Gy fractions (EQD2). Using multivariable logistic regression analyses, we examined the associations between cancer treatment and valvular abnormalities. RESULTS: We identified 225 mainly mild echocardiographic valvular abnormalities in 169 of 545 CCS (31%) with a cardiac assessment (median follow-up time, 14.9 years [range, 5.1-36.8 years]; median attained age 22.0 years [range, 7.0-49.7 years]). Twenty-four CCS (4.4%) had 31 moderate or higher-graded abnormalities. Most common abnormalities were tricuspid valve disorders (n=119; 21.8%) and mitral valve disorders (n=73; 13.4%). The risk of valvular abnormalities was associated with increasing radiation dose (using EQD2) involving the heart region (odds ratio 1.33 per 10 Gy) and the presence of congenital heart disease (odds ratio 3.43). We found no statistically significant evidence that anthracyclines increase the risk. CONCLUSIONS: Almost one-third of CCS treated with potentially cardiotoxic therapy had 1 or more asymptomatic, mostly mild valvular abnormalities after a median follow-up of nearly 15 years. The most important risk factors are higher EQD2 to the heart region and congenital heart disease. Studies with longer follow-up are necessary to investigate the clinical course of asymptomatic valvular abnormalities in CCS.

Not all fish are equal: functional biodiversity of cartilaginous fishes (Elasmobranchii and Holocephali) in Chile.

A review of the primary literature on the cartilaginous fishes (sharks, skates, rays and chimaeras), together with new information suggests that 106 species occur in Chilean waters, comprising 58 sharks, 30 skates, 13 rays and five chimaeras. The presence of 93 species was confirmed, although 30 species were encountered rarely, through validated catch records and sightings made in artisanal and commercial fisheries and on specific research cruises. Overall, only 63 species appear to have a range distribution that normally includes Chilean waters. Actual reliable records of occurrence are lacking for 13 species. Chile has a cartilaginous fish fauna that is relatively impoverished compared with the global species inventory, but conservative compared with countries in South America with warm-temperate waters. The region of highest species richness occurs in the mid-Chilean latitudes of c. 30-40° S. This region represents a transition zone with a mix of species related to both the warm-temperate Peruvian province to the north and cold-temperate Magellan province to the south. This study provides clarification of species occurrence and the functional biodiversity of Chile's cartilaginous fish fauna.

The use of equivalent radiation dose in the evaluation of late effects after childhood cancer treatment.

PURPOSE: In epidemiologic research radiation-associated late effects after childhood cancer are usually analyzed without considering fraction dose. According to radiobiological principles, fraction dose is an important determinant of late effects. We aim to provide the rationale for using equivalent dose in 2-Gy fractions (EQD2(α/ß)) as the measure of choice rather than total physical dose as prescribed according to the clinical protocol. METHODS: Between 1966 and 1996, 597 (43.8%) children in our cohort of 1,362 5-year childhood cancer survivors (CCS) received radiotherapy before the age of 18 years as part of their primary cancer treatment. Detailed information from individual patients' charts was collected and physical doses were converted into the EQD2(α/ß), which includes total dose, fraction dose, and the tissue-specific α/ß ratio. The use of EQD2(α/ß) is illustrated in examples studies describing different analyses using EQD2(α/ß) and physical dose. RESULTS: Radiotherapy information was obtained for 510 (85.4%) CCS. Multivariable analyses rendered different risk estimates for total body irradiation in EQD2(α/ß)-based vs. physical-dose-based models. For other radiotherapy regimens, risk estimates were similar. CONCLUSIONS: Using the total physical dose is not adequate for advanced analyses of radiation-associated late effects in CCS. Therefore, it is advised that for future studies the EQD2(α/ß) is used, because the EQD2(α/ß) incorporates the fraction dose, and the tissue-specific α/ß ratio. Furthermore, it enables comparisons across fractionation regimens and allows for summing doses delivered by various contemporary and future radiation modalities. IMPLICATIONS FOR CANCER SURVIVORS: Risk estimates of radiation-associated side effects expressed in EQD2(α/ß) provide more precise, clinically relevant information for cancer survivor screening guidelines.