156 research outputs found

    Exercise training has contrasting effects in myocardial infarction and pressure overload due to divergent endothelial nitric oxide synthase regulation

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    The beneficial effects of exercise training (EX) on cardiac pathology are well recognized. Previously, we found that the effects of EX on cardiac dysfunction in mice critically depend on the underlying etiology. EX exerted beneficial effects after myocardial infarction (MI); however, cardiac pathology following pressure overload produced by transverse aortic constriction (TAC) was aggravated by EX. In the presented study, we investigated whether the contrasting effects of EX on cardiac dysfunction can be explained by an etiology-specific response of endothelial nitric oxide (NO) synthase (eNOS) to EX, which divergently affects the balance between nitric oxide and superoxide. For this purpose, mice were exposed to eight weeks of voluntary wheel running or sedentary housing (SED), immediately after sham, MI, or TAC surgery. Left ventricular (LV) function was assessed using echocardiography and hemodynamic measurements. EX ameliorated LV dysfunction and remodeling after MI, but not following TAC, in which EX even aggravated fibrosis. Strikingly, EX attenuated superoxide levels after MI, but exacerbated NOS-dependent superoxide levels following TAC. Similarly, elevated eNOS S-glutathionylation and eNOS monomerization, which were observed in both MI and TAC, were corrected by EX in MI, but aggravated by EX after TAC. Additionally, EX reduced antioxidant activity in TAC, while it was maintained following EX in MI. In conclusion, the present study shows that EX mitigates cardiac dysfunction after MI, likely by attenuating eNOS uncoupling-mediated oxidative stress, whereas EX tends to aggravate cardiac dysfunction following TAC, likely due to exacerbating eNOS-mediated oxidative stress

    Dichotomy between the transcriptomic landscape of naturally versus accelerated aged murine hearts

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    We investigated the transcriptomic landscape of the murine myocardium along the course of natural aging and in three distinct mouse models of premature aging with established aging-related cardiac dysfunction. Genome-wide total RNA-seq was performed and the expression patterns of protein-coding genes and non-coding RNAs were compared between hearts from naturally aging mice, mice with cardiac-specific deficiency of a component of the DNA repair machinery, mice with reduced mitochondrial antioxidant capacity and mice with reduced telomere length. Our results demonstrate that no dramatic changes are evident in the transcriptomes of naturally senescent murine hearts until two years of age, in contrast to the transcriptome of accelerated aged mice. Additionally, these mice displayed model-specific alterations of the expression levels of protein-coding and non-coding genes with hardly any overlap with age-related signatures. Our data demonstrate very limited similarities between the transcriptomes of all our murine aging models and question their reliability to study human cardiovascular senescence

    Implementing structured, multiprofessional medical ethical decision-making in a neonatal intensive care unit

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    Background In neonatal intensive care, a child’s death is often preceded by a medical decision. Nurses, social workers and pastors, however, are often excluded from ethical case deliberation. If multiprofessional ethical case deliberations do take place, participants may not always know how to perform to the fullest. Setting A level-IIID neonatal intensive care unit of a paediatric teaching hospital in the Netherlands. Methods Structured multiprofessional medical ethical decision-making (MEDM) was implemented to help overcome problems experienced. Important features were: all professionals who are directly involved with the patient contribute to MEDM; a five-step procedure is used: exploration, agreement on the ethical dilemma/ investigation of solutions, analysis of solutions, decision-making, planning actions; meetings are chaired by an impartial ethicist. A 15-item questionnaire to survey staff perceptions on this intervention just before and 8 months after implementation was developed. Results Before and after response rates were 91/105 (87%) and 85/113 (75%). Factor analysis on the questionnaire suggested a four-factor structure: participants’ role; structure of MEDM; content of ethical deliberation; and documentation of decisions/ conclusions. Effect sizes were 1.67 (p<0.001), 0.69 (p<0.001) and 0.40 (p<0.01) for the first three factors respectively, but only 0.07 (p¼0.65) for the fourth factor. Nurses’ perceptions of improvement did not significantly exceed those of physicians. Conclusion Professionals involved in ethical case deliberation perceived that the process of decisionmaking had improved; they we

    Reproducibility via coordinated standardization:A multi-center study in a Shank2 genetic rat model for Autism Spectrum Disorders

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    Inconsistent findings between laboratories are hampering scientific progress and are of increasing public concern. Differences in laboratory environment is a known factor contributing to poor reproducibility of findings between research sites, and well-controlled multisite efforts are an important next step to identify the relevant factors needed to reduce variation in study outcome between laboratories. Through harmonization of apparatus, test protocol, and aligned and non-aligned environmental variables, the present study shows that behavioral pharmacological responses in Shank2 knockout (KO) rats, a model of synaptic dysfunction relevant to autism spectrum disorders, were highly replicable across three research centers. All three sites reliably observed a hyperactive and repetitive behavioral phenotype in KO rats compared to their wild-type littermates as well as a dose-dependent phenotype attenuation following acute injections of a selective mGluR1 antagonist. These results show that reproducibility in preclinical studies can be obtained and emphasizes the need for high quality and rigorous methodologies in scientific research. Considering the observed external validity, the present study also suggests mGluR1 as potential target for the treatment of autism spectrum disorders

    Development and validation of a prognostic score for long-term transplant-free survival in autoimmune hepatitis type 1

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    Background No prognostic score is currently available for long-term survival in autoimmune hepatitis (AIH) patients. Objective The aim of this study was to develop and validate such a prognostic score for AIH patients at diagnosis. Methods The prognostic score was developed using uni- & multivariate Cox regression in a 4-center Dutch cohort and validated in an independent 6-center Belgian cohort. Results In the derivation cohort of 396 patients 19 liver transplantations (LTs) and 51 deaths occurred (median follow-up 118 months; interquartile range 60-202 months). In multivariate analysis age (hazard ratio [HR] 1.045; p < 0.001), non-caucasian ethnicity (HR 1.897; p = 0.045), cirrhosis (HR 3.266; p < 0.001) and alanine aminotransferase level (HR 0.725; p = 0.003) were significant independent predictors for mortality or LT (C-statistic 0.827; 95% CI 0.790-0.864). In the validation cohort of 408 patients death or LT occurred in 78 patients during a median follow-up of 74 months (interquartile range: 25-142 months). Predicted 5-year event rate did not differ from observed event rate (high risk group 21.5% vs. 15.7% (95% CI: 6.3%-24.2%); moderate risk group 5.8% versus 4.3% (95% CI: 0.0%-9.1%); low risk group 1.9% versus 5.4% (95% CI: 0.0%-11.4%); C-statistic 0.744 [95% CI 0.644-0.844]). Conclusions A Dutch-Belgian prognostic score for long-term transplant-free survival in AIH patients at diagnosis was developed and validated

    Seasonal diet changes in elephant and impala in mopane woodland

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    Abstract Elephant and impala as intermediate feeders, having a mixed diet of grass and browse, respond to seasonal fluctuations of forage quality by changing their diet composition. We tested the hypotheses that (1) the decrease in forage quality is accompanied by a change in diet from more monocots in the wet season to more dicots in the dry season and that that change is more pronounced and faster in impala than in elephant; (2) mopane (Colophospermum mopane), the most abundant dicot species, is the most important species in the elephant diet in mopane woodland, whereas impala feed relatively less on mopane due to the high condensed tannin concentration; and (3) impala on nutrient-rich soils have a diet consisting of more grass and change later to diet of more browse than impala on nutrient-poor soils. The phosphorus content and in vitro digestibility of monocots decreased and the NDF content increased significantly towards the end of the wet season, whereas in dicots no significant trend could be detected. We argue that this decreasing monocot quality caused elephant and impala to consume more dicots in the dry season. Elephant changed their diet gradually over a 16-week period from 70% to 25% monocots, whereas impala changed diets rapidly (2-4 weeks) from 95% to 70% monocots. For both elephants and impala, there was a positive correlation between percentage of monocots and dicots in the diet and the in vitro digestibility of these forage items. Mopane was the most important dicot species in the elephant diet and its contribution to the diet increased significantly in the dry season, whereas impala selected other dicot species. On nutrient-rich gabbroic soils, impala ate significantly more monocots than impala from nutrient-poor granitic soils, which was related to the higher in vitro digestibility of the monocots on gabbroic soil. Digestibility of food items appears to be an important determinant of diet change from the wet to the dry season in impala and elephants

    An open-label randomised-controlled trial of azathioprine vs. mycophenolate mofetil for the induction of remission in treatment-naive autoimmune hepatitis

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    Background &amp; Aims: Patients with autoimmune hepatitis (AIH) almost invariably require lifelong immunosuppressive treatment. There is genuine concern about the efficacy and tolerability of the current standard combination therapy of prednisolone and azathioprine. Mycophenolate mofetil (MMF) has emerged as an alternative option. The aim of this study was to compare MMF to azathioprine as induction therapy for AIH. Methods: In this 24-week, prospective, randomised, open-label, multicentre superiority trial, 70 patients with treatment-naive AIH received either MMF or azathioprine, both in combination with prednisolone. The primary endpoint was biochemical remission defined as normalisation of serum levels of alanine aminotransferase and IgG after 24 weeks of treatment. Secondary endpoints included safety and tolerability. Results: Seventy patients (mean 57.9 years [SD 14.0]; 72.9% female) were randomly assigned to the MMF plus prednisolone (n = 39) or azathioprine plus prednisolone (n = 31) group. The primary endpoint was met in 56.4% and 29.0% of patients assigned to the MMF group and the azathioprine group, respectively (difference, 27.4 percentage points; 95% CI 4.0 to 46.7; p = 0.022). The MMF group exhibited higher complete biochemical response rates at 6 months (72.2% vs. 32.3%; p = 0.004). No serious adverse events occurred in patients who received MMF (0%) but serious adverse events were reported in four patients who received azathioprine (12.9%) (p = 0.034). Two patients in the MMF group (5.1%) and eight patients in the azathioprine group (25.8%) discontinued treatment owing to adverse events or serious adverse events (p = 0.018). Conclusions: In patients with treatment-naive AIH, MMF with prednisolone led to a significantly higher rate of biochemical remission at 24 weeks compared to azathioprine combined with prednisolone. Azathioprine use was associated with more (serious) adverse events leading to cessation of treatment, suggesting superior tolerability of MMF. Impact and implications: This randomised-controlled trial directly compares azathioprine and mycophenolate mofetil, both in combination with prednisolone, for the induction of biochemical remission in treatment-naive patients with autoimmune hepatitis. Achieving complete remission is desirable to prevent disease progression. Patients assigned to the mycophenolate mofetil group reached biochemical remission more often and experienced fewer adverse events. The findings in this trial may contribute to the re-evaluation of international guidelines for the standard of care in treatment-naive patients with autoimmune hepatitis. Trial registration number: #NCT02900443.</p

    An open-label randomised-controlled trial of azathioprine vs. mycophenolate mofetil for the induction of remission in treatment-naive autoimmune hepatitis

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    Background &amp; Aims: Patients with autoimmune hepatitis (AIH) almost invariably require lifelong immunosuppressive treatment. There is genuine concern about the efficacy and tolerability of the current standard combination therapy of prednisolone and azathioprine. Mycophenolate mofetil (MMF) has emerged as an alternative option. The aim of this study was to compare MMF to azathioprine as induction therapy for AIH. Methods: In this 24-week, prospective, randomised, open-label, multicentre superiority trial, 70 patients with treatment-naive AIH received either MMF or azathioprine, both in combination with prednisolone. The primary endpoint was biochemical remission defined as normalisation of serum levels of alanine aminotransferase and IgG after 24 weeks of treatment. Secondary endpoints included safety and tolerability. Results: Seventy patients (mean 57.9 years [SD 14.0]; 72.9% female) were randomly assigned to the MMF plus prednisolone (n = 39) or azathioprine plus prednisolone (n = 31) group. The primary endpoint was met in 56.4% and 29.0% of patients assigned to the MMF group and the azathioprine group, respectively (difference, 27.4 percentage points; 95% CI 4.0 to 46.7; p = 0.022). The MMF group exhibited higher complete biochemical response rates at 6 months (72.2% vs. 32.3%; p = 0.004). No serious adverse events occurred in patients who received MMF (0%) but serious adverse events were reported in four patients who received azathioprine (12.9%) (p = 0.034). Two patients in the MMF group (5.1%) and eight patients in the azathioprine group (25.8%) discontinued treatment owing to adverse events or serious adverse events (p = 0.018). Conclusions: In patients with treatment-naive AIH, MMF with prednisolone led to a significantly higher rate of biochemical remission at 24 weeks compared to azathioprine combined with prednisolone. Azathioprine use was associated with more (serious) adverse events leading to cessation of treatment, suggesting superior tolerability of MMF. Impact and implications: This randomised-controlled trial directly compares azathioprine and mycophenolate mofetil, both in combination with prednisolone, for the induction of biochemical remission in treatment-naive patients with autoimmune hepatitis. Achieving complete remission is desirable to prevent disease progression. Patients assigned to the mycophenolate mofetil group reached biochemical remission more often and experienced fewer adverse events. The findings in this trial may contribute to the re-evaluation of international guidelines for the standard of care in treatment-naive patients with autoimmune hepatitis. Trial registration number: #NCT02900443.</p

    An enzyme-linked immunosorbent assay for detection of avian influenza virus subtypes H5 and H7 antibodies

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    BACKGROUND: Avian influenza virus (AIV) subtypes H5 and H7 attracts particular attention because of the risk of their potential pathogenicity in poultry. The haemagglutination inhibition (HI) test is widely used as subtype specific test for serological diagnostics despite the laborious nature of this method. However, enzyme-linked immunosorbent assays (ELISAs) are being explored as an alternative test method. H5 and H7 specific monoclonal antibodies were experimentally raised and used in the development of inhibition ELISAs for detection of serological response specifically directed against AIV subtypes H5 and H7. The ELISAs were evaluated with polyclonal chicken anti-AIV antibodies against AIV subtypes: H1N2, H5N2, H5N7, H7N1, H7N7, H9N9, H10N4 and H16N3. RESULTS: Both the H5 and H7 ELISA proved to have a high sensitivity and specificity and the ELISAs detected H5 and H7 antibodies earlier during experimental infection than the HI test did. The reproducibility of the ELISA’s performed at different times was high with Pearson correlation coefficients of 0.96-0.98. CONCLUSIONS: The ELISAs are a potential alternative to the HI test for screening of large amounts of avian sera, although only experimental sera were tested in this study
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