Consistency of the mass variation formula for black holes accreting cosmological fluids

We address the spherical accretion of generic fluids onto black holes. We show that, if the black hole metric satisfies certain conditions, in the presence of a test fluid it is possible to derive a fully relativistic prescription for the black hole mass variation. Although the resulting equation may seem obvious due to a form of it appearing as a step in the derivation of the Schwarzschild metric, this geometrical argument is necessary to fix the added degree of freedom one gets for allowing the mass to vary with time. This result has applications on cosmological accretion models and provides a derivation from first principles to serve as a basis to the accretion equations already in use in the literature.

Heterogeneous time-dependent response of adipose tissue during the development of cancer cachexia

Cancer cachexia induces loss of fat mass that accounts for a large part of the dramatic weight loss observed both in humans and in animal models; however, the literature does not provide consistent information regarding the set point of weight loss and how the different visceral adipose tissue depots contribute to this symptom. To evaluate that, 8-week-old male Wistar rats were subcutaneously inoculated with 1 ml (2 x 10(7)) of tumour cells (Walker 256). Samples of different visceral white adipose tissue (WAT) depots were collected at days 0, 4, 7 and 14 and stored at -80 degrees C (seven to ten animals/each day per group). Mesenteric and retroperitoneal depot mass was decreased to the greatest extent on day 14 compared with day 0. Gene and protein expression of PPAR gamma(2) (PPARG) fell significantly following tumour implantation in all three adipose tissue depots while C/EBP alpha (CEBPA) and SREBP-1c (SREBF1) expression decreased over time only in epididymal and retroperitoneal depots. Decreased adipogenic gene expression and morphological disruption of visceral WAT are further supported by the dramatic reduction in mRNA and protein levels of perilipin. Classical markers of inflammation and macrophage infiltration (f4/80, CD68 and MIF-1 alpha) in WAT were significantly increased in the later stage of cachexia (although showing a incremental pattern along the course of cachexia) and presented a depot-specific regulation. These results indicate that impairment in the lipid-storing function of adipose tissue occurs at different times and that the mesenteric adipose tissue is more resistant to the 'fat-reducing effect' than the other visceral depots during cancer cachexia progression. Journal of Endocrinology (2012) 215, 363-373

Precision of Usual Food Intake Estimates According to the Percentage of Individuals with a Second Dietary Measurement

Background Statistical methods for estimating usual intake require at least two short-term dietary measurements in a subsample of the target population. However, the percentage of individuals with a second dietary measurement (replication rate) may influence the precision of estimates, such as percentiles and proportions of individuals below cut-offs of intake. Objective To investigate the precision of the usual food intake estimates using different replication rates and different sample sizes. Participants/setting Adolescents participating in the continuous National Health and Nutrition Examination Survey 2007-2008 (n=1,304) who completed two 24-hour recalls. Statistical analyses performed The National Cancer Institute method was used to estimate the usual intake of dark green vegetables in the original sample comprising 1,304 adolescents with a replication rate of 100%. A bootstrap with 100 replications was performed to estimate CIs for percentiles and proportions of individuals below cut-offs of intake. Using the same bootstrap replications, four sets of data sets were sampled with different replication rates (80%, 60%, 40%, and 20%). For each data set created, the National Cancer Institute method was performed and percentiles, Cl, and proportions of individuals below cut-offs were calculated. Precision estimates were checked by comparing each Cl obtained from data sets with different replication rates with the Cl obtained from original data set. Further, we sampled 1,000, 750, 500, and 250 individuals from the original data set, and performed the same analytical procedures. Results Percentiles of intake and percentage of individuals below the cut-off points were similar throughout the replication rates and sample sizes, but the Cl increased as the replication rate decreased. Wider CIs were observed at 40% and 20% of replication rate. Conclusions The precision of the usual intake estimates decreased when low replication rates were used. However, even with different sample sizes, replication rates >40% may not lead to an important loss of precision. J Acad Nutr Diet. 2012;112:1015-1020.

Cancer-related deaths among different treatment options in chronic coronary artery disease: results of a 6-year follow-up of the MASS II study

Introduction The primary end points of randomized clinical trials evaluating the outcome of therapeutic strategies for coronary artery disease (CAD) have included nonfatal acute myocardial infarction, the need for further revascularization, and overall mortality. Noncardiac causes of death may distort the interpretation of the long-term effects of coronary revascularization. Materials and methods This post-hoc analysis of the second Medicine, Angioplasty, or Surgery Study evaluates the cause of mortality of patients with multivessel CAD undergoing medical treatment, percutaneous coronary intervention, or surgical myocardial revascularization [coronary artery bypass graft surgery (CABG)] after a 6-year follow-up. Mortality was classified as cardiac and noncardiac death, and the causes of noncardiac death were reported. Results Patients were randomized into CABG and non-CABG groups (percutaneous coronary intervention plus medical treatment). No statistical differences were observed in overall mortality (P = 0.824). A significant difference in the distribution of causes of mortality was observed among the CABG and non-CABG groups (P = 0.003). In the CABG group, of the 203 randomized patients, the overall number of deaths was 34. Sixteen patients (47.1%) died of cardiac causes and 18 patients (52.9%) died of noncardiac causes. Of these, seven deaths (20.6%) were due to neoplasia. In the non-CABG group, comprising 408 patients, the overall number of deaths was 69. Fifty-three patients (77%) died of cardiac causes and 16 patients (23%) died of noncardiac causes. Only five deaths (7.2%) were due to neoplasia. Conclusion Different treatment options for multivessel coronary artery disease have similar overall mortality: CABG patients had the lowest incidence of cardiac death, but the highest incidence of noncardiac causes of death, and specifically a higher tendency toward cancer-related deaths. Coron Artery Dis 23:79-84 (C) 2012 Wolters Kluwer Health | Lippincott Williams & Wilkins.

Estimating total body fat using a skinfold prediction equation in Brazilian children

Background: The double burden of obesity and underweight is increasing in developing countries and simple methods for the assessment of fat mass in children are needed. Aim: To develop and validate a new anthropometric predication equation for assessment of fat mass in children. Subjects and methods: Body composition was assessed in 145 children aged 9.8 +/- 1.3 (SD) years from Sao Paulo, Brazil using dual energy X-ray absorptiometry (DEXA) and skinfold measurements. The study sample was divided into development and validation sub-sets to develop a new prediction equation for FM (PE). Results: Using multiple linear regression analyses, the best equation for predicting FM (R-2 - 0.77) included body weight, triceps skinfold, height, gender and age as independent variables. When cross-validated, the new PE was valid in this sample (R-2 = 0.80), while previously published equations were not. Conclusion: The PE was more valid for Brazilian children that existing equations, but further studies are needed to assess the validity of this PE in other populations.

On the mechanisms that limit oxygen uptake during exercise in acute and chronic hypoxia: role of muscle mass

[EN] Peak aerobic power in humans (VO2,peak) is markedly affected by inspired O2 tension (FIO2). The question to be answered in this study is what factor plays a major role in the limitation of muscle peak VO2 in hypoxia: arterial O2 partial pressure (Pa,O2) or O2 content (Ca,O2)? Thus, cardiac output (dye dilution with Cardio-green), leg blood flow (thermodilution), intra-arterial blood pressure and femoral arterial-to-venous differences in blood gases were determined in nine lowlanders studied during incremental exercise using a large (two-legged cycle ergometer exercise: Bike) and a small (one-legged knee extension exercise: Knee)muscle mass in normoxia, acute hypoxia (AH) (FIO2 = 0.105) and after 9 weeks of residence at 5260 m (CH). Reducing the size of the active muscle mass blunted by 62% the effect of hypoxia on VO2,peak in AH and abolished completely the effect of hypoxia on VO2,peak after altitude acclimatization. Acclimatization improved Bike peak exercise Pa,O2 from 34 +/- 1 in AH to 45 +/- 1 mmHg in CH(P <0.05) and Knee Pa,O2 from 38 +/- 1 to 55 +/- 2 mmHg(P <0.05). Peak cardiac output and leg blood flow were reduced in hypoxia only during Bike. Acute hypoxia resulted in reduction of systemic O2 delivery (46 and 21%) and leg O2 delivery (47 and 26%) during Bike and Knee, respectively, almost matching the corresponding reduction in VO2,peak. Altitude acclimatization restored fully peak systemic and leg O(2) delivery in CH (2.69 +/- 0.27 and 1.28 +/- 0.11 l min(-1), respectively) to sea level values (2.65 +/- 0.15 and 1.16 +/- 0.11 l min(-1), respectively) during Knee, but not during Bike. During Knee in CH, leg oxygen delivery was similar to normoxia and, therefore, also VO2,peak in spite of a Pa,O2 of 55 mmHg. Reducing the size of the active mass improves pulmonary gas exchange during hypoxic exercise, attenuates the Bohr effect on oxygen uploading at the lungs and preserves sea level convective O2 transport to the active muscles. Thus, the altitude-acclimatized human has potentially a similar exercising capacity as at sea level when the exercise model allows for an adequate oxygen delivery (blood flow x Ca,O2), with only a minor role of Pa,O2 per se, when Pa,O2 is more than 55 mmHg.

The contribution of the Finite Volume Point Dilution Method to the determination of solute mass flux in an alluvial aquifer.

Groundwater represents one of the most important resources of the world and it is essential to prevent its pollution and to consider remediation intervention in case of contamination. According to the scientific community the characterization and the management of the contaminated sites have to be performed in terms of contaminant fluxes and considering their spatial and temporal evolution. One of the most suitable approach to determine the spatial distribution of pollutant and to quantify contaminant fluxes in groundwater is using control panels. The determination of contaminant mass flux, requires measurement of contaminant concentration in the moving phase (water) and velocity/flux of the groundwater. In this Master Thesis a new solute flux mass measurement approach, based on an integrated control panel type methodology combined with the Finite Volume Point Dilution Method (FVPDM), for the monitoring of transient groundwater fluxes, is proposed. Moreover a new adsorption passive sampler, which allow to capture the variation of solute concentration with time, is designed. The present work contributes to the development of this approach on three key points. First, the ability of the FVPDM to monitor transient groundwater fluxes was verified during a step drawdown test at the experimental site of Hermalle Sous Argentau (Belgium). The results showed that this method can be used, with optimal results, to follow transient groundwater fluxes. Moreover, it resulted that performing FVPDM, in several piezometers, during a pumping test allows to determine the different flow rates and flow regimes that can occurs in the various parts of an aquifer. The second field test aiming to determine the representativity of a control panel for measuring mass flus in groundwater underlined that wrong evaluations of Darcy fluxes and discharge surfaces can determine an incorrect estimation of mass fluxes and that this technique has to be used with precaution. Thus, a detailed geological and hydrogeological characterization must be conducted, before applying this technique. Finally, the third outcome of this work concerned laboratory experiments. The test conducted on several type of adsorption material (Oasis HLB cartridge, TDS-ORGANOSORB 10 and TDS-ORGANOSORB 10-AA), in order to determine the optimum medium to dimension the passive sampler, highlighted the necessity to find a material with a reversible adsorption tendency to completely satisfy the request of the new passive sampling technique.

Population doublings and percentage of S100-positive cells as predictors of in vitro chondrogenicity of expanded human articular chondrocytes

The aim of this study was to investigate the interconnection between the processes of proliferation, dedifferentiation, and intrinsic redifferentiation (chondrogenic) capacities of human articular chondrocyte (HAC), and to identify markers linking HAC dedifferentiation status with their chondrogenic potential. Cumulative population doublings (PD) of HAC expanded in monolayer culture were determined, and a threshold range of 3.57-4.19 PD was identified as indicative of HAC loss of intrinsic chondrogenic capacity in pellets incubated without added chondrogenic factors. While several specific gene and surface markers defined early HAC dedifferentiation process, no clear correlation with the loss of intrinsic chondrogenic potential could be established. CD90 expression during HAC monolayer culture revealed two subpopulations, with sorted CD90-negative cells showing lower proliferative capacity and higher chondrogenic potential compared to CD90-positive cells. Although these data further validated PD as critical for in vitro chondrogenesis, due to the early shift in expression, CD90 could not be considered for predicting chondrogenic potential of HAC expanded for several weeks. In contrast, an excellent mathematically modeled correlation was established between PD and the decline of HAC expressing the intracellular marker S100, providing a direct link between the number of cell divisions and dedifferentiation/loss of intrinsic chondrogenic capacity. Based on the dynamics of S100-positive HAC during expansion, we propose asymmetric cell division as a potential mechanism of HAC dedifferentiation, and S100 as a marker to assess chondrogenicity of HAC during expansion, of potential value for cell-based cartilage repair treatments.

The impact of body mass index on the one year outcomes of patients treated by percutaneous coronary intervention with Biolimus- and Sirolimus-eluting stents (from the LEADERS Trial)

The aim of this analysis was to assess the effect of body mass index (BMI) on 1-year outcomes in patients enrolled in a contemporary percutaneous coronary intervention trial comparing a sirolimus-eluting stent with a durable polymer to a biolimus-eluting stent with a biodegradable polymer. A total of 1,707 patients who underwent percutaneous coronary intervention were randomized to treatment with either biolimus-eluting stents (n = 857) or sirolimus-eluting stents (n = 850). Patients were assigned to 1 of 3 groups according to BMI: normal (<25 kg/m(2)), overweight (25 to 30 kg/m(2)), or obese (>30 kg/m(2)). At 1 year, the incidence of the composite of cardiac death, myocardial infarction, and clinically justified target vessel revascularization was assessed. In addition, rates of clinically justified target lesion revascularization and stent thrombosis were assessed. Cox proportional-hazards analysis, adjusted for clinical differences, was used to develop models for 1-year mortality. Forty-five percent of the patients (n = 770) were overweight, 26% (n = 434) were obese, and 29% (n = 497) had normal BMIs. At 1-year follow-up, the cumulative rate of cardiac death, myocardial infarction, and clinically justified target vessel revascularization was significantly higher in the obese group (8.7% in normal-weight, 11.3% in overweight, and 14.5% in obese patients, p = 0.01). BMI (hazard ratio 1.47, 95% confidence interval 1.02 to 2.14, p = 0.04) was an independent predictor of stent thrombosis. Stent type had no impact on the composite of cardiac death, myocardial infarction, and clinically justified target vessel revascularization at 1 year in the 3 BMI groups (hazard ratio 1.08, 95% confidence interval 0.63 to 1.83, p = 0.73). In conclusion, BMI was an independent predictor of major adverse cardiac events at 1-year clinical follow-up. The higher incidence of stent thrombosis in the obese group may suggest the need for a weight-adjusted dose of clopidogrel.

What percentage of people in the general population satisfies the current clinical at-risk criteria of psychosis?

The clinical validity of at-risk criteria of psychosis had been questioned based on epidemiological studies that have reported much higher prevalence and annual incidence rates of psychotic-like experiences (PLEs as assessed by either self rating questionnaires or layperson interviews) in the general population than of the clinical phenotype of psychotic disorders (van Os et al., 2009). Thus, it is unclear whether “current at-risk criteria reflect behaviors so common among adolescents and young adults that a valid distinction between ill and non-ill persons is difficult” (Carpenter, 2009). We therefore assessed the 3-month prevalence of at-risk criteria by means of telephone interviews in a randomly drawn general population sample from the at-risk age segment (age 16–35 years) in the Canton Bern, Switzerland. Eighty-five of 102 subjects had valid phone numbers, 21 of these subjects refused (although 6 of them signaled willingness to participate at a later time), 4 could not be contacted. Sixty subjects (71% of the enrollment fraction) participated. Two participants met exclusion criteria (one for being psychotic, one for lack of language skills). Twenty-two at-risk symptoms were assessed for their prevalence and severity within the 3 months prior to the interview by trained clinical raters using (i) the Structured Interview for Prodromal Syndromes (SIPS; Miller et al., 2002) for the evaluation of 5 attenuated psychotic and 3 brief limited intermittent psychotic symptoms (APS, BLIPS) as well as state-trait criteria of the ultra-high-risk (UHR) criteria and (ii) the Schizophrenia Proneness Instrument, Adult version (SPI-A; Schultze-Lutter et al., 2007) for the evaluation of the 14 basic symptoms included in COPER and COGDIS (Schultze-Lutter et al., 2008). Further, psychiatric axis I diagnoses were assessed by means of the Mini-International Neuropsychiatric Interview, M.I.N.I. (Sheehan et al., 1998), and psychosocial functioning by the Scale of Occupational and Functional Assessment (SOFAS; APA, 1994). All interviewees felt ‘rather’ or ‘very’ comfortable with the interview. Of the 58 included subjects, only 1 (2%) fulfilled APS criteria by reporting the attenuated, non-delusional idea of his mind being literally read by others at a frequency of 2–3 times a week that had newly occurred 6 weeks ago. BLIPS, COPER, COGDIS or state-trait UHR criteria were not reported. Yet, twelve subjects (21%) described sub-threshold at-risk symptoms: 7 (12%) reported APS relevant symptoms but did not meet time/frequency criteria of APS, and 9 (16%) reported COPER and/or COGDIS relevant basic symptoms but at an insufficient frequency or as a trait lacking increase in severity; 4 of these 12 subjects reported both sub-threshold APS and sub-threshold basic symptoms. Table 1 displays type and frequency of the sub-threshold at-risk symptoms.

Correlation of fat embolism severity and subcutaneous fatty tissue crushing and bone fractures

Pulmonary fat embolism (PFE) is frequently encountered in blunt trauma. The clinical manifestation ranges from no impairment in light cases to death due to right-sided heart failure or hypoxaemia in severe cases. Occasionally, pulmonary fat embolism can give rise to a fat embolism syndrome (FES), which is marked by multiorgan failure, respiratory disorders, petechiae and often death. It is well known that fractures of long bones can lead to PFE. Several authors have argued that PFE can arise due to mere soft tissue injury in the absence of fractures, a claim other authors disagree upon. In this study, we retrospectively examined 50 victims of blunt trauma with regard to grade and extent of fractures and crushing of subcutaneous fatty tissue and presence and severity of PFE. Our results indicate that PFE can arise due to mere crushing of subcutaneous fat and that the fracture grade correlated well with PFE severity (p = 0.011). The correlation between PFE and the fracture severity (body regions affected by fractures and fracture grade) showed a lesser significant correlation (p = 0.170). The survival time (p = 0.567), the amount of body regions affected by fat crushing (p = 0.336) and the fat crush grade (p = 0.485) did not correlate with the PFE grade, nor did the amount of body regions affected by fractures. These results may have clinical implications for the assessment of a possible FES development, as, if the risk of a PFE is known, preventive steps can be taken.