Both acuity and long term prognosis are important Emergency Department metrics: comparison of mobility assessment with the Emergency Severity Index.

OBJECTIVE: To compare the SUHB mobility scale (i.e., stable(S), unstable gait(U), needing help to walk(H), or bedridden(B)) and the Emergency Severity Index (ESI) associations with admission and mortality outcomes. DESIGN: Post-hoc analysis of a prospective observational study including all consenting presenting to the ED over a period of 3 weeks. Odd ratios and AUCs were calculated to assess predictive performance of SUHB and compared with ESI. RESULTS: Out of 2422 patients, 65% presented with a stable gait, 45% with an ESI level 3. With increasing mobility impairment on the SUHB scale, the probability for admission and mortality increased. SUHB had a higher AUC than ESI for 1-year mortality. CONCLUSION: SUHB was a better predictor than ESI of long-term mortality. The scale, which is rapid, requires little additional training, and no extra costs, could be used as a useful supplement to the triage process.

Quantification of mechanical properties in long-term in vivo used silicone catheter lines according to DIN 10555-3.

BACKGROUND: Totally implantable central venous access port devices are crucial for intravenous application of chemotherapeutics and long-term therapy for chronic disease. Common complications include thrombosis and device fracture related to altered material properties through exposure in situ. This study exhibits whether uniaxial tensile properties (DIN 10555-3) of in vivo used catheters prove inferior to unused catheters. MATERIAL AND METHODS: 5 unused, originally packed silicone catheters were cut into 6 segments of 50 mm: 3 segments each were cleaned via cleaning solution (n = 15) while 3 segments were left unattended (n = 15). Distal segments (50 mm) of long-term in vivo used silicone catheters were cleaned before testing (n = 33). Overall mechanical behavior was tested in a custom-made self-centering, torsion free carrier. Maximum force stress at failure, strain at failure and Young's modulus were determined and statistically analyzed. FINDINGS: Unused catheters showed no significant difference in testing. in vivo used catheters exhibited 20% lower maximal force than unused catheters (p < 0.001), strain at break (p ã€ˆ0,001), and 7% higher elastic modulus (p = 0.004; power: 0.845). Due to a constant cross section area, stress at failure was proportional to maximum force (p < 0.001). Relation between determined parameters and dwell times was non-significant. INTERPRETATION: In vivo long-term used silicone catheters showed significantly lower ultimate strength than unused ones. It is likely that in situ altering changes the mechanical properties of catheters and may potentially lead to failure.

An international multidisciplinary peer-driven consensus on the optimal use of hemostatic powders in surgical practice.

Bleeding is a consequence of insufficient hemostasis and excessive bleeding at a surgical site is associated with an increased risk of post-operative infection, transfusion and re-operation, in addition to increased hospital length of stay and costs. Surgeons employ a range of methods to achieve hemostasis, including topical hemostatic agents of differing composition and properties. Hemostatic powders are a sub-group of topical hemostats, which can be used in helping as adjuncts to manage troublesome bleeding in a variety of situations. As this technology is relatively new and potentially not well known by the broad surgical community, no specific guidelines or recommendations for the optimal use of hemostatic powders in surgery currently exist. A steering group throughout Europe of multidisciplinary surgeons, expert in hemostasis and hemostatics, identified from literature and from personal experience, five key topics. When to use hemostatic powder, the evidence for use, benefits of use, safety remarks and considerations in various surgical specialties. Thirty-seven statements were subsequently drawn from these five key topics. An online survey was sent to 128 high-volume surgeons working in breast surgery, gynaecological and obstetric surgery, general and emergency surgery, thoracic surgery and urological surgery in Europe to assess agreement (consensus) with these statements. Consensus was defined as high if ≥ 75% and very high if ≥ 90% of respondents agreed with a statement. A total of 79 responses were received and consensus among the surgical experts was very high in 27 (73%) statements, high in 8 (22%) statements and was not achieved in 2 (5%) statements. Based on the consensus scores, the steering group produced 16 key recommendations which they considered could improve patient outcomes by reducing post-operative bleeding and its associated complications using hemostatic powder.

Does a lower self-concept contribute to mental health disparities of diverse immigrant youth from middle childhood to late adolescence?

BACKGROUND: Three out of ten children in Germany have immigrant backgrounds and this proportion is expected to further increase in subsequent years. While immigrant youth have been found more vulnerable to developing symptoms of depression and anxiety, the underlying mechanisms of how such disparities unfold during youth development are still understudied. Some previous research has found that immigrant youth are at risk of experiencing a less positive self-concept compared to non-immigrant youth. We investigated whether the self-concept mediates mental health disparities and explored variability in such associations from middle childhood to late adolescence. METHODS: Overall 1839 children and adolescents aged 6-21 years (M = 14.05 years, SD = 3.03, 49.8% female, n = 782 with immigrant status) participated in a cross-sectional self-report survey in classroom settings using scales from the Beck Youth Inventories II (Beck et al. in Beck Youth Inventories - Second Edition, Psychological Corporation, San Antonio, 2005) to assess self-concept and symptoms of depression and anxiety. Links between immigrant status, age, self-concept and symptom levels of depression as well as anxiety were examined using hierarchical regression and moderated mediation models. RESULTS: Immigrant youth reported higher symptom levels of depression and anxiety than their non-immigrant peers but did not differ in their self-concepts. Hypothesized moderated mediation models were not fully supported and self-concept neither mediated the link between immigrant status and depression nor immigrant status and anxiety. However, self-concept was a significant predictor for symptom levels of depression as well as anxiety, with stronger associations in adolescents. CONCLUSIONS: Our study substantiates previous findings that immigrant youth in Germany have overall increased symptom levels of depression and anxiety compared to non-immigrant youth. Our study however does not support that immigrant youth have a more negative self-concept and that the self-concept mediates such internalizing mental health disparities. Findings match previous evidence that developing a positive attitude towards the self is linked to better mental health. Beyond that, our findings suggest that mental health interventions addressing the self-concept could be especially relevant when targeting adolescents. Further research is needed to deepen the understanding of the mediating processes between migration status and mental health variables.

Bionics and green technology in maritime shipping: an assessment of the effect of Salvinia air-layer hull coatings for drag and fuel reduction.

To save energy and reduce environmental impacts, new technologies towards a development of a sustainable 'greener' economy are needed. The main opportunity to improve sustainability by reducing emissions is within the transport sector. More than 90% of all goods worldwide are transported by ships. Particularly maritime ships using heavy fuel oil and marine gas oil play a major role. The total fuel consumption of shipping in 2016 was about 250 m t (domestic ca. 50 m t, international shipping ca. 200 m t). The vast portion of the energy consumption of a ship is the need to overcome the drag between ship hull and water-depending on the shape of the vessel and its size up to 90% of total fuel consumption. This means reducing drag helps to save fuel and reduces carbon emissions as well as pollution considerably. Different techniques for drag reduction are known, e.g. the micro-bubble technique or the bulbous bow. We investigated a novel bioinspired technique since 2002: the application of biomimetic surfaces with long-term stable air layers on ship hulls, serving as a slip agent. This technology is based on the Salvinia Effect, allowing a permanent stabilization of air layers under water. In this case study, we analysed the possible savings, which also could be combined with modified micro-bubble technologies. We calculated, based on a selection of five ship types, representing 75% of the world fleet, that air-layer hull coatings could lead to estimated savings of 32.5 million tons of fuel (meaning 13.0% of the worldwide shipping fuel consumption), equal to 18.5 billion US$ and 130.0 million tons of CO2e per year. The positive impacts on global temperature and other greenhouse gases are calculated and could be a contributing factor in accomplishing the UN Sustainable Development Goals and the Paris Agreement to the UN Framework Convention on Climate Change. The study is a contribution to enhance our patchy knowledge concerning the potential economic and ecological benefit of bionics and biomimetic technologies. This article is part of the theme issue 'Bioinspired materials and surfaces for green science and technology'.

Post-mortem MRI-based volumetry of the hippocampus in forensic cases of decedents with severe mental illness.

A decrease in the volume of the hippocampus is associated with severe mental illness, especially schizophrenia, and has been studied extensively in the living using magnetic resonance imaging. Autopsy cohorts also represent a valuable data source for imaging studies. However, post-mortem magnetic resonance imaging (PMMRI) is subject to unique challenges, such as the lower core temperature of scanned subjects and the influence of decomposition processes. This study aimed to determine if results from in vivo studies could be replicated on a post-mortem cohort of decedents who suffered from severe mental illness. We included 96 decedents with either schizophrenia (n = 34), depressive disorder (n = 17), or no known psychiatric diagnosis (n = 45) from April 2015 to January 2017. All cases underwent a T2-weighted cerebral MRI less than 24 h before autopsy. We used a manual segmentation algorithm to define the hippocampus on coronal images and subsequently estimate the volume of the region. The group with schizophrenia had a statistically significant 9.5% decrease in mean hippocampal volume compared with control subjects, while the group with depression trended towards a reduced volume, but this difference was not statistically significant. Thus we were able to replicate previous results from in vivo studies. PMMRI has unique potential for research in that it can be combined with procedures possible only in the research fields of clinical pathology and forensic science, e.g. histopathological sampling.

Assessing venous thrombus in renal cell carcinoma: preliminary results for unenhanced 3D-SSFP MRI.

AIM: To test the potential of unenhanced cardiac- and respiratory-motion-corrected three-dimensional steady-state free precession (3D-SSFP) magnetic resonance imaging (MRI) for the assessment of inferior vena cava (IVC) thrombus in patients with clear-cell renal cell carcinoma (cRCC), compared to standard contrast-enhanced (CE)-MRI and CE-computed tomography (CT). MATERIALS AND METHODS: Eighteen patients with cRCC and IVC thrombus, who received CE-MRI and 3D-SSFP at 1.5 T between June 2015 and December 2017, were included. The diagnostic performance of 3D-SSFP in determining the level of thrombus extension, contrast-to-noise ratio (CNR), and image quality were compared with standard MRI/CT and validated against intraoperative and histopathology results. RESULTS: There was 100% agreement between 3D-SSFP, 83.3% agreement between CE-MRI, and 71.4% agreement between CE-CT and surgical findings regarding the level of IVC thrombus. In addition, 3D-SSFP showed a slightly superior estimate of pathological IVC volume. 3D-SSFP reached a significantly higher CNR in the supra- and infrarenal IVC compared to the morphological sequence T2-weighted half-Fourier axial single-shot fast spin-echo (T2-HASTE) and all phases of CE-MRI. More specifically, 3D-SSFP showed a significantly higher CNR in the infrarenal IVC (mean CNR of 10.09±5.74 versus 4.21±2.33 in the delayed phase, p≤0.001) and in the suprarenal IVC (mean CNR of 9.22±4.11 versus 4.84±5.74 in the late arterial phase, p=0.015). CE-CT also was significantly inferior to 3D-SSFP (p≤0.01) and slightly inferior to CE-MRI (p>0.05). The thrombus delineation score for 3D-SSFP (4.38±0.67) was higher compared to CE-MRI (3.76±0.56, p=0.005). CONCLUSION: This preliminary study indicates that 3D-SSFP can achieve an accurate assessment of IVC thrombus in cRCC patients without the need for contrast medium administration, being superior to standard MRI and CT.

Test method for mechanical properties of implantable catheters according to DIN 10555-3.

To enable causal analysis of port catheter failure, this study aimed to develop an experimental setup for uniaxial tensile tests that addresses the specific requirements of highly elastic medical catheters; and to quantify parameters of the catheters' mechanical competence with respect to effects of artificial aging. Segments of 6F-polyurethane catheters were tested in their native status, after chemical and after mechanical aging. Tension experiments were performed with a rate of 220 mm/min until catheter failure. Material behavior was analyzed based on load cell measurements of the universal test system and an additional optical distance registration. The Young's modulus, the ultimate stress and the ultimate strain were determined. Chemical aging significantly decreased Young's modulus (84%; p = 0.001) and ultimate stress (83%; p < 0.001), whereas mechanical aged samples demonstrated similar results for the Young's modulus (p = 0.772) and a non-significant rise of ultimate stress (13%; p = 0.128). Ultimate strain did not differ significantly regardless of the pretreatment. The results proof reliability, reproducibility and sensitivity to quantify artificial aging induced variations and also promise to detect deviations in material features caused by long-term clinical usage of catheters.

Radiologically inserted gastrostomy: differences of maintenance of balloon- vs. loop-retained devices.

PURPOSE: To compare outcome and associated complications of ballon- vs. loop-retained devices for radiologically inserted gastrostomy (RIG). METHODS: From 2007 to 2011 233 patients (age 63.7 ± 10.6 years) were referred for a RIG because of pharyngeal stricture Intervention was performed with four different devices: balloon-retained - Freka® GastroTube, Fresenius Kabi (n = 121); MIC® Gastrostomy Feeding Tube, Kimberly-Clark (n = 34); Russell® Gastrostomy Tray, Cook Medical Inc. (n = 17); and loop-retained - Tilma® Gastrostomy Set, Cook Medical Inc. (n = 50). Follow-up was performed with regard to RIG-related complications, cause of removal and fatalities. Revision-free survival times after RIG were evaluated using Kaplan-Meier analysis and group differences by log-rank tests. For analysis of demographic and methodical variables multivariate Cox regression models were used. RESULTS: With a primary technical success rate of 95.3% (222/233) a total of 92 instances of revisions were necessary in 66 patients (66/233, 28.3%) during follow-up (mean 182.8 ± 86.6 days). The most common complication was tube dislodgement (14.3%). There were no significant differences between the distinct devices (p = 0.098), but analyzing the data in subgroups of balloon-compared to loop-retained gastrostomy tubes we observed a significantly higher probability of minor complications for the latter (p = 0.023). CONCLUSION: As it is significantly less prone to minor complications we recommend the use of balloon-retained gastrostomy tubes to improve the practicability and maintenance of RIG.

Does the onset of bone metastasis in sunitinib-treated renal cell carcinoma patients impact the overall survival?

PURPOSE: To evaluate the impact of bone metastasis (BM) onset toward prognosis in metastatic renal cell carcinoma (mRCC) patients treated with sunitinib. METHODS: mRCC patients with BM and sunitinib as first targeted therapy between May 2005 and December 2012 were retrospectively analyzed. Patients with synchronous (s) BM or metachronous (m) BM were compared with regard to treatment and outcome [time to clinical progression (TTcP), overall survival (OS), skeletal-related events (SRE)]. Descriptive statistics, Kaplan-Meier estimation of TTcP and OS, Cox regression analyses, and a landmark analysis were administered. RESULTS: BM was identified in 127 mRCC patients; thereof, 82 sunitinib-treated patients were analyzed [sBM n = 57 (69.5 %), mBM n = 25 (30.5 %)]. Higher tumor grading (p = 0.029), male predominance (p = 0.02), and less second-line therapy (p = 0.001) were detected in sBM compared to mBM. SRE remained similar between subgroups (p = 0.462). TTcP during sunitinib was similar [median sBM 8.1 (95 % CI 3.9-12.3) vs. mBM 8.7 (95 % CI 2.7-14.8) months, p = 0.903]. OS remained significantly inferior in sBM patients compared to mBM [median sBM 21.1 (95 % CI 16-26.2) months vs. mBM 38.5 (95 % CI 15-62) months, p = 0.001], which was confirmed by landmark analyses at 1.5, 3, 6, 9, and 12 months. However, OS after occurrence of BM was similar in both groups [median sBM 24.2 (95 % CI 17.3-31.1) months vs. mBM 17.2 (95 % CI 8.4-26) months, p = 0.519]. CONCLUSIONS: mBM is associated with an improved OS compared to sBM in mRCC with sunitinib treatment, despite similar efficacy of sunitinib treatment in both groups of patients.

A field investigation on transport of carbon-supported nanoscale zero-valent iron (nZVI) in groundwater.

The application of nanoscale zero-valent iron (nZVI) for subsurface remediation of groundwater contaminants is a promising new technology, which can be understood as alternative to the permeable reactive barrier technique using granular iron. Dechlorination of organic contaminants by zero-valent iron seems promising. Currently, one limitation to widespread deployment is the fast agglomeration and sedimentation of nZVI in colloidal suspensions, even more so when in soils and sediments, which limits the applicability for the treatment of sources and plumes of contamination. Colloid-supported nZVI shows promising characteristics to overcome these limitations. Mobility of Carbo-Iron Colloids (CIC) - a newly developed composite material based on finely ground activated carbon as a carrier for nZVI - was tested in a field application: In this study, a horizontal dipole flow field was established between two wells separated by 5.3m in a confined, natural aquifer. The injection/extraction rate was 500L/h. Approximately 1.2kg of CIC was suspended with the polyanionic stabilizer carboxymethyl cellulose. The suspension was introduced into the aquifer at the injection well. Breakthrough of CIC was observed visually and based on total particle and iron concentrations detected in samples from the extraction well. Filtration of water samples revealed a particle breakthrough of about 12% of the amount introduced. This demonstrates high mobility of CIC particles and we suggest that nZVI carried on CIC can be used for contaminant plume remediation by in-situ formation of reactive barriers.

Geographical distribution of torture: An epidemiological study of torture reported by asylum applicants examined at the Department of Forensic Medicine, University of Copenhagen.

Using reports from 154 examinations of alleged torture victims among asylum applicants to Denmark conducted by the Department of Forensic Medicine, University of Copenhagen, between 2001 and 2013, we have categorized the victims into four geographical regions, as well as according to the conflict that caused them to flee. The torture incidents described by the victims were divided into 12 different categories defined by the Istanbul Protocol. These data were cross referenced in order to identify any differences in the prevalence of the 12 forms of torture. The study showed that crush injuries were only reported by refugees from Asia, including Afghanistan and Pakistan, and that incidents of electrical torture were reported twice as frequently by torture victims from Middle Eastern and North African countries, though it was lower among Iraqis, Iranians and ethnic Kurds. Sexual torture was reported by 78% of females and 25% of males.

Age-related differences in the activity of arterial mineral deposition and regional bone metabolism: a 18F-sodium fluoride positron emission tomography study.

UNLABELLED: Functional (18)F-fluoride PET demonstrated an inverse relationship between the activity of arterial mineral deposition and regional bone metabolism. While bone metabolism decreases with age, the activity of arterial mineral deposition increases. INTRODUCTION: The extent of arterial calcification increases with age, whereas bone mineral density decreases, evidencing a well-known inverse correlation on morphological basis. The aim of this study was to evaluate the functional relationship between the activity of arterial mineral deposition and regional bone metabolism as assessed by (18)F-sodium fluoride (NaF) PET/CT. METHODS: Three hundred four subjects were examined by (18)F-NaF PET/CT. Tracer accumulation in the femoral arteries was analyzed both qualitatively and semiquantitatively by measuring the blood-pool-corrected standardized uptake value (target-to-background ratio). Uptake was compared with cardiovascular risk factors (RFs), calcified plaque burden, and regional bone metabolism as assessed by PET/CT. RESULTS: The activity of arterial mineral deposition significantly increased with age (p < 0.001), whereas regional bone metabolism significantly decreased (p < 0.001). There was a significant inverse correlation between bone metabolism and arterial mineral deposition (unadjusted, p < 0.001); that association was not significant (p = 0.79) when controlled for age and other RFs. Both high activity of arterial mineral deposition and low bone metabolism were significantly associated with cardiovascular events and other RFs. CONCLUSION: (18)F-NaF PET/CT provides a tool to visualize and quantify the activity of arterial mineral deposition and regional bone metabolism. In this study, we observed an inverse correlation between the activity of arterial mineral deposition and regional bone metabolism. While the activity of arterial mineral deposition significantly increases with age, regional bone metabolism decreases.

The heavy metals cadmium, lead and mercury in raw materials of animal origin: evaluation of data from practice.

Raw materials from animal origin are widely used in homoeopathy. Due to the lack of dedicated limits, the quality requirements for herbal drugs of the European Pharmacopoeia (Ph. Eur.) and/or the German Homoeopathic Pharmacopoeia (Homöopathisches Arzneibuch, HAB), including limits for heavy metals such as cadmium, lead and mercury, have been applied. A recent database evaluation shows that for some raw materials of animal origin the Ph. Eur. limits for herbal drugs cannot be met in practice. For this reason proposals for new limits for cadmium, lead and mercury are made based on recent experiences from the companies' daily practice. These specific limits are suggested to be included in the individual monographs of the Ph. Eur. or at least the German HAB, respectively, for Ambra grisea, Euspongia officinalis, Formica rufa and Sepia officinalis.

[Propensity score comparison of the various radical surgical techniques for high-risk prostate cancer]. / Propensity Score Vergleich der verschiedenen radikalen Operationstechniken beim high risk Prostatakarzinom.

INTRODUCTION: The optimal surgical treatment of patients with a high risk prostate cancer (PCa) in terms of radical prostatectomy (RP) is still controversial: open retropubic RP (RRP), laparoscopic RP (LRP), or robot-assisted (RARP). We aimed to investigate the influence of the different surgical techniques on pathologic outcome and biochemical recurrence. PATIENTS AND METHODS: A total of 805 patients with a high risk PCa (PSA >20 ng/mL, Gleason Score ≥8, or clinical stage ≥cT2c) were included. A comparison of 407 RRP patients with 398 minimally invasive cases (LRP+RARP) revealed significant confounders. Therefore all 110 RARP cases were propensity score (PS) matched 1:1 with LRP and RRP patients. PS included age, clinical stage, preoperative PSA, biopsy Gleason score, surgeon's experience and application of a nerve sparing technique. Comparison of overall survival (OS) and recurrence-free survival (RFS) was done with the log rank test. Predictors of RFS were analyzed by means of Cox regression models. RESULTS: Within the post-matching cohort of 330 patients a pathologic Gleason score < 7, = 7 and > 7 was found in 1.8, 55.5 and 42.7% for RARP, in 8.2, 36.4, 55.5% for LRP and in 0, 60.9 and 39.1% for RRP (p=0.004 for RARP vs. LRP and p=0.398 for RARP vs. RRP). Differences in histopathologic stages were not statistically significant. The overall positive surgical margin rate (PSM) as well as PSM for ≥ pT3 were not different. PSM among patients with pT2 was found in 15.7, 14.0 and 20.0% for RARP, LRP and RRP (statistically not significant). The respective mean 3-year RFS rates were 41.4, 77.9, 54.1% (p<0.0001 for RARP vs. LRP and p=0.686 for RARP vs. RRP). The mean 3-year OS was calculated as 95.4, 98.1 and 100% respectively (statistically not significant). CONCLUSION: RARP for patients with a high risk PCa reveals similar pathologic and oncologic outcomes compared with LRP and RRP.

Method transfer, partial validation, and cross validation: recommendations for best practices and harmonization from the global bioanalysis consortium harmonization team.

This paper presents the recommendations of the Global Bioanalytical Consortium Harmonization Team on method transfer, partial validation, and cross validation. These aspects of bioanalytical method validation, while important, have received little detailed attention in recent years. The team has attempted to define, separate, and describe these related activities, and present practical guidance in how to apply these techniques.

Tumour shrinkage measured with first treatment evaluation under VEGF-targeted therapy as prognostic marker in metastatic renal cell carcinoma (mRCC).

BACKGROUND: The aim of our analysis is to further characterise the prognostic relevance of early tumour shrinkage (TS) during VEGF-targeted therapy in mRCC, in order to explore whether this could define a group of patients with long-term survivorship. METHODS: A hundred patients were stratified into five subgroups according to their change of tumour size with first treatment evaluation: -100% to -60%; -59% to -30% and -29% to 0% TS or gain of tumour size from 1% to 19% and ≤20% or occurrence of new lesions (i.e., progressive disease). RESULTS: The median PFS and OS were 10.4 months and 28.2 months, respectively. The median OS stratified according to the subgroups as described above was 77.4, 33.5, 26.9, 30.0 and 14.3 months, respectively. Multivariate analysis revealed early TS as a prognostic marker (P=0.021; HR 1.624). CONCLUSION: The extent of TS defines a small proportion of patients with an excellent prognosis. Larger studies are warranted to define the relationship of long-term survivorship and extent of TS with targeted therapies.

Hybridization in natural sympatric populations of Dermacentor ticks in northwestern North America.

Hybridization in ticks has been described in a handful of species and mostly as a result of laboratory experiments. We used 148 AFLP loci to describe putative hybridization events between D. andersoni and D. variabilis in sympatric populations from northwestern North America. Recently, D. variabilis has expanded its range westward into the natural range of D. andersoni. Using a sample of 235 D. andersoni and 62 D. variabilis, we identified 31 individuals as putative hybrids: four F2 individuals and 27 backcrosses to D. andersoni (as defined by NewHybrids). We found no evidence of hybrids backcrossing into D. variabilis. Furthermore, all hybrids presented 16S mtDNA signatures characteristic of D. andersoni, which indicates the directionality of the hybrid crosses: female D. andersoni × male D. variabilis. We also discovered 13 species-specific AFLP fragments for D. andersoni. These loci were found to have a decreased occurrence in the putative hybrids and were absent altogether in D. variabilis samples. AFLP profiles were also used to determine the levels of genetic population structure and gene flow among nine populations of D. andersoni and three of D. variabilis. Genetic structure exists in both species (D. andersoni, ΦST = 0.110; D. variabilis, ΦST = 0.304) as well as significant estimates of isolation by distance (D. andersoni, ρ = 0.066, P = 0.001; D. variabilis, ρ = 0.729, P = 0.001).

Functional characterization of isolated, perfused outermedullary descending human vasa recta.

AIM: The renal medulla plays an important role in the control of water and salt balance by the kidney. Outer medullary descending vasa recta (OMDVR) are microscopic vessels providing blood flow to the renal medulla. Data on the physiology of human vasa recta are scarce. Therefore, we established an experimental model of human single isolated, perfused OMDVR and characterized their vasoactivity in response to angiotensin II and to pressure changes. METHODS: Human non-malignant renal tissue was obtained from patients undergoing nephrectomy due to renal cell carcinoma. OMDVR were dissected under magnification and perfused using concentric microscopic pipettes. The response of OMDVR to angiotensin II and pressure changes was quantified in serial pictures. All patients signed a consent form prior to surgery. RESULTS: Outer medullary descending vasa recta constricted significantly after bolus applications of angiotensin II. OMDVR constriction to angiotensin II was also concentration dependent. Response to luminal pressure changes was different according to the diameter of vessels, with larger OMDVR constricting after pressure increase, while smaller ones did not. CONCLUSION: Outer medullary descending vasa recta constrict in response to angiotensin II and pressure increases. Our results show that OMDVR may take part in the regulation of medullary blood flow in humans. Our model may be suitable for investigating disturbances of renal medullary circulation in human subjects.