Detection of testosterone administration based on the carbon isotope ratio profiling of endogenous steroids: international reference populations of professional soccer players.

BACKGROUND AND OBJECTIVES: The determination of the carbon isotope ratio in androgen metabolites has been previously shown to be a reliable, direct method to detect testosterone misuse in the context of antidoping testing. Here, the variability in the 13C/12C ratios in urinary steroids in a widely heterogeneous cohort of professional soccer players residing in different countries (Argentina, Italy, Japan, South Africa, Switzerland and Uganda) is examined. METHODS: Carbon isotope ratios of selected androgens in urine specimens were determined using gas chromatography/combustion/isotope ratio mass spectrometry (GC-C-IRMS). RESULTS: Urinary steroids in Italian and Swiss populations were found to be enriched in 13C relative to other groups, reflecting higher consumption of C3 plants in these two countries. Importantly, detection criteria based on the difference in the carbon isotope ratio of androsterone and pregnanediol for each population were found to be well below the established threshold value for positive cases. CONCLUSIONS: The results obtained with the tested diet groups highlight the importance of adapting the criteria if one wishes to increase the sensitivity of exogenous testosterone detection. In addition, confirmatory tests might be rendered more efficient by combining isotope ratio mass spectrometry with refined interpretation criteria for positivity and subject-based profiling of steroids.

Some go without a cigarette: characteristics of cannabis users who have never smoked tobacco.

OBJECTIVES: To estimate the prevalence of youth who use cannabis but have never been tobacco smokers and to assess the characteristics that differentiate them from those using both substances or neither substance. DESIGN: School survey. SETTING: Postmandatory schools. PARTICIPANTS: A total of 5263 students (2439 females) aged 16 to 20 years divided into cannabis-only smokers (n = 455), cannabis and tobacco smokers (n = 1703), and abstainers (n = 3105). OUTCOME MEASURES: Regular tobacco and cannabis use; and personal, family, academic, and substance use characteristics. RESULTS: Compared with those using both substances, cannabis-only youth were younger (adjusted odds ratio [AOR], 0.82) and more likely to be male (AOR, 2.19), to play sports (AOR, 1.64), to live with both parents (AOR, 1.33), to be students (AOR, 2.56), and to have good grades (AOR, 1.57) and less likely to have been drunk (AOR, 0.55), to have started using cannabis before the age of 15 years (AOR, 0.71), to have used cannabis more than once or twice in the previous month (AOR, 0.64), and to perceive their pubertal timing as early (AOR, 0.59). Compared with abstainers, they were more likely to be male (AOR, 2.10), to have a good relationship with friends (AOR, 1.62), to be sensation seeking (AOR, 1.32), and to practice sports (AOR, 1.37) and less likely to have a good relationship with their parents (AOR, 0.59). They were more likely to attend high school (AOR, 1.43), to skip class (AOR, 2.28), and to have been drunk (AOR, 2.54) or to have used illicit drugs (AOR, 2.28). CONCLUSIONS: Cannabis-only adolescents show better functioning than those who also use tobacco. Compared with abstainers, they are more socially driven and do not seem to have psychosocial problems at a higher rate.

Stable hydrogen and oxygen isotope composition of waters from mine tailings in different climatic environments

The stable isotope composition of waters (delta H-2, delta O-18) can be used as a natural tracer of hydrologic processes in systems affected by acid mine drainage. We investigated the delta H-2 and delta O-18 values of pore waters from four oxidizing sulfidic mine tailings impoundments in different climatic regions of Chile (Piuquenes at La Andina with Alpine climate, Cauquenes and Caren at El Teniente with Mediterranean climate, and Talabre at the Chuquicamata deposit with hyperarid climate). No clear relationship was found between altitude and isotopic composition. The observed displacement of the tailings pore waters from the local meteoric water line toward higher delta O-18 values (by similar to +2% delta O-18 relative to delta H-2) is partly due to water-rock interaction processes, including hydration and O-isotope exchange with sulfates and Fe(III) oxyhydroxides produced by pyrite oxidation. In most tailings, from the saturated zone toward the surface, isotopically different zones can be distinguished. Zone I is characterized by an upward depletion of H-2 and O-18 in the pore waters from the saturated zone and the lowermost vadose zone, due to ascending diffused isotopically light water triggered by the constant loss of water vapor by evaporation at the surface. In zone II, the capillary flow of a mix of vapor and liquid water causes an evaporative isotopic enrichment in H-2 and O-18. At the top of the tailings in dry climate a zone III between the capillary zone and the surface contains isotopically light diffused and atmospheric water vapor. In temperate climates, the upper part of the profile is affected by recent rainfall and zone III may not differ isotopically from zone II.

Stable isotope composition of smectite in suevites at the Ries crater, Germany: Implications for hydrous alteration of impactites

The 24-km diameter Ries crater, Germany, exhibits well-preserved crater filling and surficial melt-rich breccia deposits that are believed to have been altered by post-impact hydrothermal fluids. The alteration mineralogy of the crater filling breccias is characterized by clay (smectite, chlorite) and a zeolite assemblage, and secondary clay phases (smectite, minor halloysite) in surficial melt-bearing breccia deposits. Using stable isotope analysis of secondary smectitic clay fractions, evidence of significant hydrous alteration of impactites at large water/rock ratios was found. The estimated fluid temperatures, using data derived by delta(18)O and delta D fractionation, suggest smectite precipitation in surficial breccias in equilibrium with meteoric fluids at temperatures 16 +/- 5 degrees C in agreement with the long-term variation of modern precipitation in the area. The stable isotope composition of smectite in crater-fill breccia, however, suggests a trend of monotonously increasing temperatures from 43 to 112 degrees C. with increasing depth through the breccia sequence. This demonstrates a different origin of alteration and temperature distribution for the surficial and crater filling melt-bearing impact breccias in the Ries crater. Our results suggest that the inverted structure of hydrothermal systems observed in some terrestrial impact craters, including the Ries crater, could indicate the initial configuration of a thermal anomaly in the crater filling sequence, but which is replaced with a normal hydrothermal convection in crater proper, during the course of post-impact cooling. (C) 2010 Elsevier B.V. All rights reserved.

Cellular schwannomas of the intracranial and intraspinal compartment: morphological and immunological characteristics compared with classical benign schwannomas.

The concept of cellular schwannoma as an unusual benign tumor is well established for peripheral nerves but has never been tested in neurosurgical series. In order to test the validity of this concept in cranial nerves and spinal roots we performed an analysis of the clinical and morphological characteristics of 12 cellular and 166 classical benign schwannomas. Immunohistochemical detection of antigen expression in Schwann cells including proliferating cell nuclear antigen (PCNA) was also performed. This study shows that cellular schwannomas in neurosurgical series manifest at a lower age than the classical benign variant and occur mainly in the spinal roots. Mitotic activity and sinusoidal vessels appear more frequently in cellular schwannomas and constitute with high cellularity, the most valuable criteria separating both entities. The postoperative course in both types of tumors was free of metastases or sarcomatous changes. Immunoexpression of S-100 protein, vimentin, epithelial membrane antigen and glial fibrillary acidic protein is not statistically different between the two variants. In contrast, PCNA is more highly expressed in cellular schwannomas. These These results confirm the concept that cellular schwannomas are a clinico-pathological variant of benign schwannomas and provide significant support for the introduction of this entity in neurosurgical oncology.

Characteristics of infections associated with external ventricular drains of cerebrospinal fluid.

OBJECTIVES: Manifestations of external ventricular drain (EVD) - associated infections overlap with those of the underlying neurosurgical conditions. We analyzed characteristics of EVD-associated infections. METHODS: We included patients aged ≥18 years with EVD-associated infections from 1997 to 2008, using modified CDC criteria for nosocomial infections. Hospital charts were reviewed retrospectively and the in-hospital outcome was evaluated. RESULTS: Forty-eight patients with EVD-associated infections were included (median age, 52 years, range 20-74 years). The median EVD-indwelling time was 7 days (range, 1-39 days) and EVD-associated infection occurred 6 days after insertion (range, 1-17 days). In 23% of patients, meningitis occurred 1-10 days after EVD removal. Fever >38 °C was present in 79% of patients, but Glasgow Coma Scale (GCS) scores were reduced in only 29%, and headache, vomiting and/or neck stiffness were present in only 31%. The median cerebrospinal fluid (CSF) leukocyte count was higher at onset of EVD-associated infection than at EVD insertion (175 × 10(6)/l versus 46 × 10(6)/l, p = 0.021), but other CSF parameters did not differ significantly. The most commonly implicated organisms were coagulase-negative staphylococci (63%) and Propionibacterium acnes (15%). CONCLUSIONS: Fever and increased CSF leukocytes should raise the suspicion of EVD-associated infection, which may occur up to 10 days after removal of EVD.

Prevalence and characteristics of periodic leg movements during sleep in the general population : the Hypnolaus study

Objective: The aim of this study was to describe the prevalence and characteristics of periodic legs movements of sleep (PLMS) in theadult general population. Methods: Data from 2162 subjects (51.2% women, mean SD age:58, 11 years, range: 40.5-84.4 years) participating in a population-based cohort study (HypnoLaus, Lausanne, Switzerland) wascollected. They completed a series of sleep related questionnaires and underwent polysomnographic recordings at home. PLMS index(PLMSI) was determined according to AASM 2007 criteria. APLMSI>15/h was considered to be of potential clinical significance. Conclusions: PLMS are highly prevalent in the general population. Age, male gender and RLS are independent predictors of a PLMSIhigher than 15/h. Further studies are needed to evaluate the clinical impact of PLMS.

Innovative method for carbon dioxide determination in human postmortem cardiac gas samples using headspace-gas chromatography-mass spectrometry and stable labeled isotope as internal standard.

A novel approach to measure carbon dioxide (CO2) in gaseous samples, based on a precise and accurate quantification by (13)CO2 internal standard generated in situ is presented. The main goal of this study was to provide an innovative headspace-gas chromatography-mass spectrometry (HS-GC-MS) method applicable in the routine determination of CO2. The main drawback of the GC methods discussed in the literature for CO2 measurement is the lack of a specific internal standard necessary to perform quantification. CO2 measurement is still quantified by external calibration without taking into account analytical problems which can often occur considering gaseous samples. To avoid the manipulation of a stable isotope-labeled gas, we have chosen to generate in situ an internal labeled standard gas ((13)CO2) on the basis of the stoichiometric formation of CO2 by the reaction of hydrochloric acid (HCl) with sodium hydrogen carbonate (NaH(13)CO3). This method allows a precise measurement of CO2 concentration and was validated on various human postmortem gas samples in order to study its efficiency.

Anatomy of contaminated aquifers of an industrial site: insights from the stable isotope compositions of waters and dissolved inorganic carbon

The hydrogen and oxygen isotopes of water and the carbon isotope composition of dissolved inorganic carbon (DIC) from different aquifers at an industrial site, highly contaminated by organic pollutants representing residues of the former gas production, have been used as natural tracers to characterize the hydrologic system. On the basis of their stable isotope compositions as well as the seasonal variations, different groups of waters (precipitation, surface waters, groundwaters and mineral waters) as well as seasonably variable processes of mixing between these waters can clearly be distinguished. In addition, reservoir effects and infiltration rates can be estimated. In the northern part of the site an influence of uprising mineral waters within the Quaternary aquifers, presumably along a fault zone, can be recognized. Marginal infiltration from the Neckar River in the cast and surface water infiltration adjacent to a steep hill on the western edge of the site with an infiltration rate of about one month can also be resolved through the seasonal variation. Quaternary aquifers closer to the centre of the site show no seasonal variations, except for one borehole close to a former mill channel and another borehole adjacent to a rain water channel. Distinct carbon isotope compositions and concentrations of DIC for these different groups of waters reflect variable influence of different components of the natural carbon cycle: dissolution of marine carbonates in the mineral waters, biogenic, soil-derived CO2 in ground- and surface waters, as well as additional influence of atmospheric CO2 for the surface waters. Many Quaternary aquifer waters have, however, distinctly lower delta(13)C(DIC) values and higher DIC concentrations compared to those expected for natural waters. Given the location of contaminated groundwaters at this site but also in the industrially well-developed valley outside of this site, the most likely source for the low C-13(DIC) values is a biodegradation of anthropogenic organic substances, in particular the tar oils at the site.

Personal indebtedness, community characteristics and theft crimes

Becker (1968) and Stigler (1970) provide the germinal works for an economic analysis of crime, and their approach has been utilised to consider the response of crime rates to a range of economic, criminal and socioeconomic factors. Until recently however this did not extend to a consideration of the role of personal indebtedness in explaining the observed pattern of crime. This paper uses the Becker (1968) and Stigler (1970) framework, and extends to a fuller consideration of the relationship between economic hardship and theft crimes in an urban setting. The increase in personal debt in the past decade has been significant, which combined with the recent global recession, has led to a spike in personal insolvencies. In the context of the recent recession it is important to understand how increases in personal indebtedness may spillover into increases in social problems like crime. This paper uses data available at the neighbourhood level for London, UK on county court judgments (CCJ's) granted against residents in that neighbourhood, this is our measure of personal indebtedness, and examines the relationship between a range of community characteristics (economic, socio-economic, etc), including the number of CCJ's granted against residents, and the observed pattern of theft crimes for three successive years using spatial econometric methods. Our results confirm that theft crimes in London follow a spatial process, that personal indebtedness is positively associated with theft crimes in London, and that the covariates we have chosen are important in explaining the spatial variation in theft crimes. We identify a number of interesting results, for instance that there is variation in the impact of covariates across crime types, and that the covariates which are important in explaining the pattern of each crime type are largely stable across the three periods considered in this analysis.

Clinician characteristics, communication, and patient outcome in oncology: a systematic review.

OBJECTIVE: The aim of this study was to review the literature on clinician characteristics influencing patient-clinician communication or patient outcome in oncology. METHODS: Studies investigating the association of clinician characteristics with quality of communication and with outcome for adult cancer patients were systematically searched in MEDLINE, PSYINFO, PUBMED, EMBASE, CINHAL, Web of Science and The Cochrane Library up to November 2012. We used the preferred reporting items for systematic reviews and meta-analyses statement to guide our review. Articles were extracted independently by two of the authors using predefined criteria. RESULTS: Twenty seven articles met the inclusion criteria. Clinician characteristics included a variety of sociodemographic, relational, and personal characteristics. A positive impact on quality of communication and/or patient outcome was reported for communication skills training, an external locus of control, empathy, a socioemotional approach, shared decision-making style, higher anxiety, and defensiveness. A negative impact was reported for increased level of fatigue and burnout and expression of worry. Professional experience of clinicians was not related to communication and/or to patient outcome, and divergent results were reported for clinician gender, age, stress, posture, and confidence or self-efficacy. CONCLUSIONS: Various clinician characteristics have different effects on quality of communication and/or patient outcome. Research is needed to investigate the pathways leading to effective communication between clinicians and patients. Copyright © 2013 John Wiley & Sons, Ltd.