Stable hydrogen isotope ratios in crystal water of clay minerals

Hydrogen is the most abundant element in the Universe. But the utilization of the H isotopic composition (δH-2 value) of soil to elucidate biogeochemical processes or to serve as a palaeo climate proxy is still in its infancy. In our research, we will focus on the δH-2 value of nonexchangeable H in the clay fraction of soils. The δH-2 value of structural H in clay minerals – mainly from C-poor subsoils - has been studied since the 1970s. The δH-2 value of clay minerals mainly depends on (a) the average δH-2 value of ambient water at the site and time of formation, and on (b) the size of the equilibrium isotopic fractionation factor between water and clay mineral at the temperature of formation. In our research, we will focus on the δH-2 value of nonexchangeable H in the clay fraction of soils. Only nonexchangeable H in in structural water of minerals preserves its inherited δH-2 value and does not exchange with water at temperatures usually occurring in soil environments at the Earth’s surface. Nonexchangeable H is bound in crystal water, which integrates the δH-2 value of soil water over several millennia. This is in turn determined by palaeoclimatic variations of the precipitation’s δH-2 signal with distinguishable shifts e.g., from Pleistocene to Holocene. For a global data set, Ruppenthal (2014) reported a close correlation of bulk soil δH-2 values with those of the mean local precipitation and confirmed this for organic matter, while the clay fraction of soils was up to now not studied. We will adapt a steam equilibration method with water vapor of known H isotopic composition – formerly applied by Ruppenthal (2014) on SOM and bulk soil – to clay fractions and compare our results to the hitherto used heating treatments (200-250°C) under vacuum. We expect that the δH-2 signal of the clay fraction of Bt horizons will serve to differentiate soils developed in different climatic epochs (e.g., Holocene, last interstadial, last interglacial) by analyzing dated palaeo soil samples. To test the hypothesis that there is a similar global regression line of the δH-2 values in structural water of clay as up to now reported for bulk soils and soil organic matter, we will analyze the clay fraction in a global set of soil samples

Stable hydrogen isotope ratios in soil organic matter

Stable H isotope ratios are a promising indicator of OM transformation processes (Schimmelmann et al., 2006). δ2H values of bulk organic matter and of specific organic compounds can be used as ecological tracer and forensic tool if the proportion of H that readily exchanges with ambient moisture is accounted for (Wassenaar & Hobson, 1998). There are a few reports about the H isotope ratios in plant-soil systems illustrating that there is little knowledge of the controls of the isotopic composition of the non-exchangeable H fraction of bulk OM (Schimmelmann et al., 2006; Ruppenthal et al., 2015). The increasingly closer relationship between δ2H values of rainfall and of non-exchangeable H in OM (δ2Hn) in the order, plant – plant litter (above- and belowground) – soil along a climatic gradient (Ruppenthal et al., 2015) suggests that decomposition influences δ2Hn values in OM in a systematic way. However, there are knowledge gaps concerning the fractionation factors and the extent of incorporation of ambient water-H into the nonexchangeable fraction of H in OM during decomposition. Our research will focus on the mechanisms responsible for the strong correlation between δ2H values in rainfall and δ2Hn values of SOM. Therefore, our study aims to investigate (1) the incorporation of ambient water-H into the nonexchangeable H fraction in OM during decomposition by heterotrophic bacteria as model organisms and quantify apparent fractionation factors, (2) the extent of incorporation of ambient water into the nonexchangeable H fraction of OM by the soil microbial community under laboratory conditions, and (3) the extent to which H is incorporated into nonexchangeable OM pool from ambient water during decomposition of aboveground litter under field conditions. We will work with microcosms using two bacteria species and determine decomposition rates of litter. Steam equilibration (Ruppenthal et al., 2015) and TC/EA-IRMS are used as analytical tools. We expect that different decomposition rates because of differences in litter quality will be reflected by the extent of H incorporation from ambient water into the nonexchangeable H fraction of the products. Additionally, different litter types enriched in 2H will be buried in soil of forest stands. We hypothesize that the incorporation of 2H-depleted ambient water into 2H-enriched nonexchangeable H fraction of OM will depend on litter type, soil moisture/ temperature, and the heterotrophic activity during the experiment

CE–MS-based urinary biomarkers to distinguish non-significant from significant prostate cancer

BACKGROUND: Prostate cancer progresses slowly when present in low risk forms but can be lethal when it progresses to metastatic disease. A non-invasive test that can detect significant prostate cancer is needed to guide patient management. METHODS: Capillary electrophoresis/mass spectrometry has been employed to identify urinary peptides that may accurately detect significant prostate cancer. Urine samples from 823 patients with PSA (<15 ng/ml) were collected prior to biopsy. A case–control comparison was performed in a training set of 543 patients (nSig = 98; nnon-Sig = 445) and a validation set of 280 patients (nSig = 48, nnon-Sig = 232). Totally, 19 significant peptides were subsequently combined by a support vector machine algorithm. RESULTS: Independent validation of the 19-biomarker model in 280 patients resulted in a 90% sensitivity and 59% specificity, with an AUC of 0.81, outperforming PSA (AUC = 0.58) and the ERSPC-3/4 risk calculator (AUC = 0.69) in the validation set. CONCLUSIONS: This multi-parametric model holds promise to improve the current diagnosis of significant prostate cancer. This test as a guide to biopsy could help to decrease the number of biopsies and guide intervention. Nevertheless, further prospective validation in an external clinical cohort is required to assess the exact performance characteristics

Acceptance, Prevalence and Indications for Robot-Assisted Laparoscopy - Results of a Survey Among Urologists in Germany, Austria and Switzerland

Background: Robotic-assisted laparoscopy (RAL) is being widely accepted in the field of urology as a replacement for conventional laparoscopy (CL). Nevertheless, the process of its integration in clinical routines has been rather spontaneous. Objective: To determine the prevalence of robotic systems (RS) in urological clinics in Germany, Austria and Switzerland, the acceptance of RAL among urologists as a replacement for CL and its current use for 25 different urological indications. Materials and Methods: To elucidate the practice patterns of RAL, a survey at hospitals in Germany, Austria and Switzerland was conducted. All surgically active urology departments in Germany (303), Austria (37) and Switzerland (84) received a questionnaire with questions related to the one-year period prior to the survey. Results: The response rate was 63%. Among the participants, 43% were universities, 45% were tertiary care centres, and 8% were secondary care hospitals. A total of 60 RS (Germany 35, Austria 8, Switzerland 17) were available, and the majority (68%) were operated under public ownership. The perception of RAL and the anticipated superiority of RAL significantly differed between robotic and non-robotic surgeons. For only two urologic indications were more than 50% of the procedures performed using RAL: pyeloplasty (58%) and transperitoneal radical prostatectomy (75%). On average, 35% of robotic surgeons and only 14% of non-robotic surgeons anticipated RAL superiority in some of the 25 indications. Conclusions: This survey provides a detailed insight into RAL implementation in Germany, Austria and Switzerland. RAL is currently limited to a few urological indications with a small number of high-volume robotic centres. These results might suggest that a saturation of clinics using RS has been achieved but that the existing robotic capacities are being utilized ineffectively. The possible reasons for this finding are discussed, and certain strategies to solve these problems are offered

Fibronectin 1 mRNA expression correlates with advanced disease in renal cancer

<p>Abstract</p> <p>Background</p> <p>Fibronectin 1 (<it>FN1</it>) is a glycoprotein involved in cellular adhesion and migration processes. The aim of this study was to elucidate the role of <it>FN1 </it>in development of renal cell cancer (RCC) and to determine a prognostic relevance for optimal clinical management.</p> <p>Methods</p> <p>212 renal tissue samples (109 RCC, 86 corresponding tissues from adjacent normal renal tissue and 17 oncocytomas) were collected from patients undergoing surgery for renal tumors and subjected to total RNA extraction. Detection of <it>FN1 </it>mRNA expression was performed using quantitative real time PCR, three endogenous controls, renal proximal tubular epithelial cells (RPTEC) as biological control and the ΔΔCt method for calculation of relative quantities.</p> <p>Results</p> <p>Mean tissue specific <it>FN1 </it>mRNA expression was found to be increased approximately seven fold comparing RCC and corresponding kidney control tissues (p < 0.001; ANOVA). Furthermore, tissue specific mean <it>FN1 </it>expression was increased approx. 11 fold in clear cell compared to papillary RCC (p = 9×10^-5; Wilcoxon rank sum test). Patients with advanced disease had higher <it>FN1 </it>expression when compared to organ-confined disease (p < 0.001; Wilcoxon rank sum test). Applying subgroup analysis we found a significantly higher <it>FN1 </it>mRNA expression between organ-confined and advanced disease in the papillary and not in the clear cell RCC group (p = 0.02 vs. p = 0.2; Wilcoxon rank sum test). There was an increased expression in RCC compared to oncocytoma (p = 0.016; ANOVA).</p> <p>Conclusions</p> <p>To our knowledge, this is the first study to show that <it>FN1 </it>mRNA expression is higher in RCC compared to normal renal tissue. <it>FN1 </it>mRNA expression might serve as a marker for RCC aggressiveness, indicating early systemic progression particularly for patients with papillary RCC.</p

Management of Sporadic Renal Angiomyolipomas: A Systematic Review of Available Evidence to Guide Recommendations from the European Association of Urology Renal Cell Carcinoma Guidelines Panel

CONTEXT: Little is known about the natural history of sporadic angiomyolipomas (AMLs); there is uncertainty regarding the indications of treatment and treatment options. OBJECTIVE: To evaluate the indications, effectiveness, harms, and follow-up of different management modalities for sporadic AML to provide guidance for clinical practice. EVIDENCE ACQUISITION: A systematic review of the literature was undertaken, incorporating Medline, Embase, and the Cochrane Library (from 1 January 1990 to 30 June 2017), in accordance with Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. No restriction on study design was imposed. Patients with sporadic AML were included. The main interventions included active surveillance, surgery (nephron-sparing surgery and radical nephrectomy), selective arterial embolisation, and percutaneous or laparoscopic thermal ablations (radiofrequency, microwaves, or cryoablation). The outcomes included indications for active treatment, AML growth rate, AML recurrence rate, risk of bleeding, post-treatment renal function, adverse events of treatments, and modalities of follow-up. Risk of bias assessment was performed using standard Cochrane methods. EVIDENCE SYNTHESIS: Among 2704 articles identified, 43 were eligible for inclusion (zero randomised controlled trials, nine nonrandomised comparative retrospective studies, and 34 single-arm case series). Most studies were retrospective and uncontrolled, and had a moderate to high risk of bias. CONCLUSIONS: In active surveillance series, spontaneous bleeding was reported in 2% of patients and active treatment was undertaken in 5%. Active surveillance is the most chosen option in 48% of the cases, followed by surgery in 31% and selective arterial embolisation in 17% of the cases. Selective arterial embolisation appeared to reduce AML volume but required secondary treatment in 30% of the cases. Surgery (particularly nephron-sparing surgery) was the most effective treatment in terms of recurrence and need for secondary procedures. Thermal ablation was an infrequent option. The association between AML size and the risk of bleeding remained unclear; as such the traditional 4-cm cut-off should not per se trigger active treatment. In spite of the limitations and uncertainties relating to the evidence base, the findings may be used to guide and inform clinical practice, until more robust data emerge. PATIENT SUMMARY: Sporadic angiomyolipoma (AML) is a benign tumour of the kidney consisting of a mixture of blood vessels, fat, and muscle. Large tumours may have a risk of spontaneous bleeding. However, the size beyond which these tumours need to be treated remains unclear. Most small AMLs can be monitored without any active treatment. For those who need treatment, options include surgical removal of the tumour or stopping its blood supply (selective embolisation). Surgery has a lower recurrence rate and lower need for a repeat surgical procedure

Caveolin 1 protein expression in renal cell carcinoma predicts survival

<p>Abstract</p> <p>Background</p> <p>Caveolae play a significant role in disease phenotypes such as cancer, diabetes, bladder dysfunction, and muscular dystrophy. The aim of this study was to elucidate the caveolin-1 <it>(</it>CAV1<it>) </it>protein expression in renal cell cancer (RCC) and to determine its potential prognostic relevance.</p> <p>Methods</p> <p>289 clear cell RCC tissue specimens were collected from patients undergoing surgery for renal tumors. Both cytoplasmic and membranous CAV1 expression were determined by immunohistochemistry and correlated with clinical variables. Survival analysis was carried out for 169 evaluable patients with a median follow up of 80.5 months (interquartile range (IQR), 24.5 - 131.7 months).</p> <p>Results</p> <p>A high CAV1 expression in the tumor cell cytoplasm was significantly associated with male sex (p = 0.04), a positive nodal status (p = 0.04), and poor tumor differentiation (p = 0.04). In contrast, a higher than average (i.e. > median) CAV1 expression in tumor cell membranes was only linked to male sex (p = 0.03). Kaplan-Meier analysis disclosed significant differences in 5-year overall (51.4 vs. 75.2%, p = 0.001) and tumor specific survival (55.3 vs. 80.1%, p = 0.001) for patients with higher and lower than average cytoplasmic CAV1 expression levels, respectively. Applying multivariable Cox regression analysis a high CAV1 protein expression level in the tumor cell cytoplasm could be identified as an independent poor prognostic marker of both overall (p = 0.02) and tumor specific survival (p = 0.03) in clear cell RCC patients.</p> <p>Conclusion</p> <p>Over expression of caveolin-1 in the tumour cell cytoplasm predicts a poor prognosis of patients with clear cell RCC. CAV1 is likely to be a useful prognostic marker and may play an important role in tumour progression. Therefore, our data encourage further investigations to enlighten the role of CAV1 and its function as diagnostic and prognostic marker in serum and/or urine of RCC patients.</p

Does Applicability Domain Exist in Microarray-Based Genomic Research?

Constructing an accurate predictive model for clinical decision-making on the basis of a relatively small number of tumor samples with high-dimensional microarray data remains a very challenging problem. The validity of such models has been seriously questioned due to their failure in clinical validation using independent samples. Besides the statistical issues such as selection bias, some studies further implied the probable reason was improper sample selection that did not resemble the genomic space defined by the training population. Assuming that predictions would be more reliable for interpolation than extrapolation, we set to investigate the impact of applicability domain (AD) on model performance in microarray-based genomic research by evaluating and comparing model performance for samples with different extrapolation degrees. We found that the issue of applicability domain may not exist in microarray-based genomic research for clinical applications. Therefore, it is not practicable to improve model validity based on applicability domain