22 research outputs found

    The EDIBLES Survey. VII. A survey of C2 and C3 in interstellar clouds

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    We carried out a sensitive survey of C2_2 and C3_3 using the EDIBLES data set. We also expanded our searches to C4_4, C5_5, and 13^{13}C12^{12}C isotopologue in the most molecule-rich sightlines. We fit synthetic spectra generated following a physical excitation model to the C2_2 (2-0) Phillips band to obtain the C2_2 column density (NN) as well as the kinetic temperature (TkinT_\textrm{kin}) and number density (nn) of the host cloud. The C3_3 molecule was measured through its A~X~\tilde{A} - \tilde{X} (000-000) electronic origin band system. We simulated the excitation of this band with a double-temperature Boltzmann distribution. We present the largest combined survey of C2_2 and C3_3 to date in which the individual transitions can be resolved. In total we detected C2_2 in 51 velocity components along 40 sightlines, and C3_3 in 31 velocity components along 27 sightlines. The two molecules are detected in the same velocity components. We find a very good correlation between NN(C2_2) and NN(C3_3) with Pearson r=0.93r = 0.93 and an average NN(C2_2)/NN(C3_3) ratio of 15.5±\pm1.4. A comparison with the behaviour of the C2_2 DIBs shows that there are no clear differences among sightlines with and without detection of C2_2 and C3_3. This is in direct contrast to the better-studied non-C2_2 DIBs who have reduced strengths in molecule-rich environments. We also identify for the first time the QQ(2), QQ(3), and QQ(4) transitions of the 13^{13}C12^{12}C (2-0) Phillips band in a stacked average spectrum, and estimate the isotopic ratio of carbon 12^{12}C/13^{13}C as 79±\pm8. Our search for the C4_4 and C5_5 optical bands was unsuccessful.Comment: 31 pages, 23 figures. To appear in A&

    The ESO Diffuse Interstellar Bands Large Exploration Survey EDIBLES: I. Project description, survey sample and quality assessment

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    The carriers of the diffuse interstellar bands (DIBs) are largely unidentified molecules ubiquitously present in the interstellar medium (ISM). After decades of study, two strong and possibly three weak near-infrared DIBs have recently been attributed to the C+ 60 fullerene based on observational and laboratory measurements. There is great promise for the identification of the over 400 other known DIBs, as this result could provide chemical hints towards other possible carriers. In an effort to systematically study the properties of the DIB carriers, we have initiated a new large-scale observational survey: the ESO Diffuse Interstellar Bands Large Exploration Survey (EDIBLES). The main objective is to build on and extend existing DIB surveys to make a major step forward in characterising the physical and chemical conditions for a statistically significant sample of interstellar lines-of-sight, with the goal to reverse-engineer key molecular properties of the DIB carriers. EDIBLES is a filler Large Programme using the Ultraviolet and Visual Echelle Spectrograph at the Very Large Telescope at Paranal, Chile. It is designed to provide an observationally unbiased view of the presence and behaviour of the DIBs towards early-spectraltype stars whose lines-of-sight probe the diffuse-to-translucent ISM. Such a complete dataset will provide a deep census of the atomic and molecular content, physical conditions, chemical abundances and elemental depletion levels for each sightline. Achieving these goals requires a homogeneous set of high-quality data in terms of resolution (R ~ 70 000 – 100 000), sensitivity (S/N up to 1000 per resolution element), and spectral coverage (305–1042 nm), as well as a large sample size (100+ sightlines). In this first paper the goals, objectives and methodology of the EDIBLES programme are described and an initial assessment of the data is provided

    Effect of enrofloxacin treatment on plasma endotoxin during bovine Escherichia coli mastitis.

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    Objective and design: To investigate the effect of enrofloxacin on endotoxin resorption during bovine Escherichia coli mastitis. Animals: 12 healthy early postpartum Holstein cows. Treatment: Mastitis was induced by intramammary infusion of 10(4) cfu E. coli P4:O32. Six cows were treated twice according to the usual enrofloxacin therapy: 5 mg/kg enrofloxacin 1) intravenously at 10 h and 2) subcutaneously at 30 h after challenge. The other 6 cows served as non-treated controls. Methods: Blood and milk samples were collected at several time points after challenge. LPS in plasma was quantified using the limulus amoebocyte lysate (LAL) assay. The somatic cell count (SCC) and cfu of milk samples were also analysed. Results: Occasional LPS peaks were detected in the plasma of 2 control cows at 6 h post-challenge and of 1 enrofloxacin-treated cow at 10 h post-challenge (P < 0.01 and P < 0.05, respectively, in comparison with time 0), just before enrofloxacin treatment. After enrofloxacin treatment, no significant LPS amounts were detected in the plasma of treated cows, but neither in the control cows. Conclusion: During induced coliform mastitis, LPS resorption in plasma occured only sporadically and within 10 h post-challenge. Whereas enrofloxacin treatment clearly limited bacterial growth in milk, significant effects on LPS resorption could not be detected. This suggests that enrofloxacin treatment of E. coli mastitis is predominantly beneficial by its bactericidal activity and is not associated with enhanced resorption of endotoxins

    Assessing the Complex Causes of Kidney Allograft Loss

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    BACKGROUND: Although graft loss is a primary endpoint in many studies in kidney transplantation and a broad spectrum of risk factors has been identified, the eventual causes of graft failure in individual cases remain ill studied. METHODS: We performed a single-center cohort study in 1000 renal allograft recipients, transplanted between March 2004 and February 2013. RESULTS: In total, 365 graft losses (36.5%) were identified, of which 211 (57.8%) were due to recipient death with a functioning graft and 154 (42.2%) to graft failure defined as return to dialysis or retransplantation. The main causes of recipient death were malignancy, infections, and cardiovascular disease. The main causes of graft failure were distinct for early failures, where structural issues and primary nonfunction prevailed, compared to later failures with a shift towards chronic injury. In contrast to the main focus of current research efforts, pure alloimmune causes accounted for only 17.5% of graft failures and only 7.4% of overall graft losses, although 72.7% of cases with chronic injury as presumed reason for graft failure had prior rejection episodes, potentially suggesting that alloimmune phenomena contributed to the chronic injury. CONCLUSIONS: In conclusion, this study provides better insight in the eventual causes of graft failure, and their relative contribution, highlighting the weight of nonimmune causes. Future efforts aimed to improve outcome after kidney transplantation should align with the relative weight and expected impact of targeting these causes.status: publishe

    Antibody-mediated rejection with and without donor-specific anti-human leucocyte antigen antibodies: performance of the peripheral blood 8-gene expression assay

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    BACKGROUND: Recently a peripheral blood 8-gene expression assay was developed for non-invasive detection of antibody-mediated rejection (ABMR) after kidney transplantation. Its value has not yet been evaluated in detail in clinical scenarios with different baseline disease probability [human leucocyte antigen donor-specific antibodies (HLA-DSA)-positive versus HLA-DSA-negative cases at the time of stable graft function versus graft dysfunction]. METHODS: Here we investigated the diagnostic accuracy of the 8-gene expression assay for histology of ABMR (ABMRh) with or without HLA-DSA in a cross-sectional cohort study of 387 blood samples with a concomitant graft biopsy. RESULTS: In patients with HLA-DSA (n = 64), the 8-gene expression assay discriminated DSA-positive ABMRh (DSAposABMRh) cases (n = 16) with good diagnostic performance {area under the receiver operating characteristic curve [AUROC] 83.1% [95% confidence interval (CI) 70.8-95.3]}. Also, in HLA-DSA-negative samples (n = 323), a clinically relevant diagnostic performance for DSAnegABMRh cases was found (n = 30) with an AUROC of 75.8% (95% CI 67.4-84.4). The 8-gene assay did not discriminate DSAposABMRh cases from DSAnegABMRh cases. There was a net benefit for clinical decision-making when adding the 8-gene expression assay to a clinical model consisting of estimated glomerular filtration rate, proteinuria, HLA-DSA and age. CONCLUSION: The 8-gene expression assay shows great potential for implementation in the clinical follow-up of high-risk HLA-DSA-positive patients and clinical relevance in HLA-DSA-negative cases.status: publishe

    Mesangial matrix expansion in a novel mouse model of diabetic kidney disease associated with the metabolic syndrome

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    Introduction: The evolution of structural changes of diabetic nephropathy in human kidneys is not well documented. Instead, rodent models are used to study diabetic nephropathy in greater detail. However, all rodent models to date are subject to important limitations, and not representative for the more complex human setting where type 2 diabetes mellitus is often accompanied by the metabolic syndrome, induced by a high-fructose western diet. Objectives: To evaluate whether a novel mouse model of metabolic syndrome could be used as valid model for preclinical studies on diabetic nephropathy. Materials and Methods: We established a model of type 2 diabetes mellitus induced by a highsucrose/high-fat (HSHF) diet in female LDL-receptor knockout C57BL/6J mice and used manual morphometry to examine the renal histological changes in this model. Results: The HSHF diet induced a metabolic syndrome with weight gain, hyperinsulinemia, insulin resistance, type 2 diabetes mellitus, and hyperlipidemia. After 16 weeks on the HSHF diet, morphometric examination of kidney biopsies demonstrated increased mesangial matrix expansion, no glomerulosclerosis, and only discrete morphological changes in glomeruli. Mesangial matrix expansion was highly correlated with biological features of the metabolic syndrome. Conclusion: We describe a novel, accessible mouse model with features of the metabolic syndrome and development of mesangial matrix expansion. This model is comparable to the human setting and could serve as a relevant experimental model for nephropathy associated with type 2 diabetes mellitus. By assessing both morphological and morphometric features we demonstrated the increased sensitivity and more detailed evaluation of manual morphometry over visual estimation by light microscopy

    Correlation and Interchangeability of Venous and Capillary Blood Gases in Non-Critically Ill Neonates

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    Background: Venous blood gas (VBG) is frequently used in the neonatal unit as alternative for capillary blood gas (CBG). However, studies reporting correlation are conflicting and data on interchangeability in neonates are lacking. Objective: We investigated the correlation and interchangeability of the components between VBG and CBG in infants admitted to the neonatal intensive care unit. Methods: In a prospective study in the neonatal unit in Leiden University Medical Center (Netherlands), simultaneously VBG and CBG were withdrawn in neonates when both venous puncture and intravenous access as blood gas monitoring was indicated. From each blood gas analysis, a Pearson correlation, intraclass correlation, and Bland-Altman analysis was performed. Clinically acceptable difference for each blood gas value was defined up-front by means of an absolute difference: pH ± 0.05; partial pressure of carbon dioxide (pCO2) (±0.67 kPa = 5 mmHg); partial pressure of oxygen (pO2) (±0.67 kPa = 5 mmHg); base excess ± 3 mmol/l; and bicarbonate (HCO3-) ± 3 mmol/l. Results: In 93 patients [median gestational age 31 (IQR 29-34) weeks], 193 paired samples of VBG and CBG were collected. The Pearson correlation between VBG and CBG was very strong for pH (r = 0.79; P < 0.001), BE (r = 0.90; P < 0.001) and bicarbonate (r = 0.87; P < 0.001); strong for pCO2 (r = 0.68; P < 0.001); and moderate for pO2 (r = 0.31; P < 0.001). The percentage of the interchangeability within our acceptable absolute difference for pH was 88%, pCO2 72%, pO2 55%, BE 90%, and bicarbonate 94%. Conclusion: VBG and CBG in neonates are well correlated and mostly interchangeable, except for pO2

    Diagnostic performance of kSORT, a blood-based mRNA assay for noninvasive detection of rejection after kidney transplantation: A retrospective multicenter cohort study

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    The Kidney Solid Organ Response Test (kSORT) blood gene expression assay was developed to noninvasively detect acute rejection (AR) after kidney transplantation. Its performance in a setting with natural disease prevalence has not been evaluated. A retrospective, multicenter cohort study was conducted across all single kidney transplant recipients, transplanted between 2011 and 2015, with samples within the first year after transplantation available in existing biobanks. The primary objective was to determine the diagnostic performance of the kSORT assay to detect AR (T cell-mediated and/or antibody-mediated rejection) as compared to a concomitant renal biopsy. AR was reported on the concomitant biopsy in 188 of 1763 (10.7%) blood samples and any rejection (including borderline changes) in 614 of 1763 (34.8%) blood samples. In 320 of 1763 samples (18.2%) the kSORT risk category was indeterminate. The kSORT assay had no diagnostic value for AR (area under the curve [AUC] 0.51, 95% confidence interval [CI] 0.50-0.56; P = .46) overall, or when considering indication biopsies (N = 487) and protocol-specified biopsies (N = 1276) separately (AUC of 0.53, 95% CI 0.50-0.59, P = .44 and 0.55, 95% CI 0.50-0.61, P = .09, respectively). This large retrospective study utilizing samples obtained under real-world clinical conditions, was unable to validate the kSORT assay for detection of AR in the first year after transplantation.status: publishe

    Occurrence of Diabetic Nephropathy After Renal Transplantation Despite Intensive Glycemic Control: An Observational Cohort Study

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    OBJECTIVE: The kinetics and risk factors of diabetic nephropathy after kidney transplantation remain unclear. This study investigated the posttransplant occurrence of diabetic nephropathy and the contribution of posttransplant glycemic control. RESEARCH DESIGN AND METHODS: We performed a single-center prospective cohort study of 953 renal allograft recipients and 3,458 protocol-specified renal allograft biopsy specimens up to 5 years after transplantation. The effects of pretransplant diabetes and glycemic control (glycated hemoglobin levels) on the posttransplant histology were studied. RESULTS: Before transplantation, diabetes was present in 164 (17.2%) renal allograft recipients, primarily type 2 (n = 146 [89.0%]). Despite intensive glycemic control (glycated hemoglobin 7.00 ± 1.34% [53 ± 14.6 mmol/mol], 6.90 ± 1.22% [52 ± 13.3 mmol/mol], and 7.10 ± 1.13% [54 ± 12.4 mmol/mol], at 1, 2, and 5 years after transplantation), mesangial matrix expansion reached a cumulative incidence of 47.7% by 5 years in the pretransplant diabetes group versus 27.1% in patients without diabetes, corresponding to a hazard ratio of 1.55 (95% CI 1.07-2.26; P = 0.005). Mesangial matrix expansion was not specific for diabetic nephropathy and associated independently with increasing age. Pretransplant diabetes was associated with posttransplant proteinuria but not with estimated glomerular filtration rate, graft failure, or any other structural changes of the glomerular, vascular, or tubulointerstitial renal compartments. The occurrence of diabetic nephropathy was independent of posttransplant glycated hemoglobin levels. CONCLUSIONS: Mesangial matrix expansion, an early indicator of diabetic nephropathy, can occur rapidly in patients with diabetes before transplantation, despite intensive glycemic control. Prevention of diabetic nephropathy requires more than pursuing low levels of glycated hemoglobin.status: publishe
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