In Situ pH Measurement in Partly Frozen Aqueous Solution Using the Fluorescent Probe 8-Hydroxypyrene-1,3,6-Trisulfonic Acid

A method based on the fluorescence probe 8-hydroxypyrene-1,3,6-trisulfonic acid for in situ measurement of pH in partly frozen aqueous solutions was developed using multifrequency, phase-modulated fluorescence spectroscopy inherently correcting for light scattering. The probe was determined to have pK _a = 7.72 ± 0.03 at 25.0 °C extrapolated to zero ionic strength with as derived from temperature dependence (5 to 25 °C investigated). Ionic strength dependence of pK _a determined experimentally was described using Debye–Hückel formalism for ionic strength up to 3 M. Temperature and ionic strength dependence were combined to yield for determination of pH at subzero temperatures with α experimentally determined from the ratio between fluorescence intensity after excitation at 454 and 415 nm, α = FI(454 nm)/2.5·FI(415 nm). Fluorescence could be described as a decay of a single excited state with a fluorescence life time of 5.40 ± 0.05 ns at 25 °C, and excited state acid–base equilibration was shown not to interfere with the pH measurement. Using the method, pH of a 0.25 M phosphate buffer with pH = 6.8 at 25 °C was shown to decrease gradually to pH = 4.2 in the ice slurry at −13 °C.     

Cardiovascular disease is increased prior to onset of rheumatoid arthritis but not osteoarthritis: the population-based Nord-Tr?ndelag health study (HUNT)

Introduction

Patients with rheumatoid arthritis (RA) have increased risk of cardiovascular (CV) events. We sought to test the hypothesis that due to increased inflammation, CV disease and risk factors are associated with increased risk of future RA development.

Methods

The population-based Nord-Trøndelag health surveys (HUNT) were conducted among the entire adult population of Nord-Trøndelag, Norway. All inhabitants 20 years or older were invited, and information was collected through comprehensive questionnaires, a clinical examination, and blood samples. In a cohort design, data from HUNT2 (1995–1997, baseline) and HUNT3 (2006–2008, follow-up) were obtained to study participants with RA (n = 786) or osteoarthritis (n = 3,586) at HUNT3 alone, in comparison with individuals without RA or osteoarthritis at both times (n = 33,567).

Results

Female gender, age, smoking, body mass index, and history of previous CV disease were associated with self-reported incident RA (previous CV disease: odds ratio 1.52 (95% confidence interval 1.11-2.07). The findings regarding previous CV disease were confirmed in sensitivity analyses excluding participants with psoriasis (odds ratio (OR) 1.70 (1.23-2.36)) or restricting the analysis to cases with a hospital diagnosis of RA (OR 1.90 (1.10-3.27)) or carriers of the shared epitope (OR 1.76 (1.13-2.74)). History of previous CV disease was not associated with increased risk of osteoarthritis (OR 1.04 (0.86-1.27)).

Conclusion

A history of previous CV disease was associated with increased risk of incident RA but not osteoarthritis.     

Modulation of Lck function through multisite docking to T cell-specific adapter protein

T cell-specific adapter protein (TSAd), encoded by the SH2D2A gene, interacts with Lck through its C terminus and thus modulates Lck activity. Here we mapped Lck phosphorylation and interaction sites on TSAd and evaluated their functional importance. The three C-terminal TSAd tyrosines Tyr(280), Tyr(290), and Tyr(305) were phosphorylated by Lck and functioned as docking sites for the Lck Src homology 2 (SH2) domain. Binding affinities of the TSAd Tyr(P)(280) and Tyr(P)(290) phosphopeptides to the isolated Lck SH2 domain were similar to that observed for the Lck Tyr(P)(505) phosphopeptide, whereas the TSAd Tyr(P)(305) peptide displayed a 10-fold higher affinity. The proline-rich Lck SH3-binding site on TSAd as well as the Lck SH2 domain were required for efficient tyrosine phosphorylation of TSAd by Lck. Interaction sites on TSAd for both Lck SH2 and Lck SH3 were necessary for TSAd-mediated modulation of proximal TCR signaling events. We found that 20-30% of TSAd molecules are phosphorylated in activated T cells and that the proportion of TSAd to Lck molecules in such cells is approximately 1:1. Therefore, in activated T cells, a considerable number of Lck molecules may potentially be engaged by TSAd. In conclusion, Lck binds to TSAd prolines and phosphorylates and interacts with the three C-terminal TSAd tyrosines. We propose that through multivalent interactions with Lck, TSAd diverts Lck from phosphorylating other substrates, thus modulating its functional activity through substrate competition.     

Certolizumab pegol plus methotrexate 5-year results from the rheumatoid arthritis prevention of structural damage (RAPID) 2 randomized controlled trial and long-term extension in rheumatoid arthritis patients

IntroductionAs patients with rheumatoid arthritis (RA) receive treatment with anti-tumour necrosis factors over several years, it is important to evaluate their long-term safety and efficacy. The objective of this study was to examine the safety and benefits of certolizumab pegol (CZP)+methotrexate (MTX) treatment for almost 5 years in patients with RA.MethodsPatients who completed the 24-week Rheumatoid Arthritis Prevention of Structural Damage (RAPID) 2 randomized controlled trial (RCT; {"type":"clinical-trial","attrs":{"text":"NCT00160602","term_id":"NCT00160602"}}NCT00160602), or who were American College of Rheumatology (ACR) 20 non-responders at Week 16, entered the open-label extension (OLE; {"type":"clinical-trial","attrs":{"text":"NCT00160641","term_id":"NCT00160641"}}NCT00160641). After ≥6 months treatment with CZP 400 mg every two weeks (Q2W), dose was reduced to 200 mg Q2W, the approved maintenance dose. Safety data are presented from all patients who received ≥1 dose CZP (Safety population, n=612). Efficacy data are presented to Week 232 for the intent-to-treat (ITT, n=492) and Week 24 CZP RCT Completer (n=342) populations, and through 192 weeks of dose-reduction for the Dose-reduction population (patients whose CZP dose was reduced to 200 mg, n=369). Radiographic progression (modified total Sharp score change from RCT baseline >0.5) to Week 128 is reported for the Week 24 CZP Completers.ResultsIn the RCT, 619 patients were randomized to CZP+MTX (n=492) or placebo+MTX (n=127). Overall, 567 patients (91.6%) entered the OLE: 447 CZP and 120 placebo patients. Of all randomized patients, 358 (57.8%) were ongoing at Week 232. Annual drop-out rates during the first four years ranged from 8.4–15.0%. Event rates per 100 patient-years were 163.0 for adverse events (AEs) and 15.7 for serious AEs. Nineteen patients (3.1%) had fatal AEs (incidence rate=0.8). Clinical improvements in the RCT were maintained to Week 232 in the CZP Completers: mean Disease Activity Score 28 (Erythrocyte Sedimentation Rate) change from baseline was −3.4 and ACR20/50/70 responses 68.4%/47.1%/25.1% (non-responder imputation). Similar improvements observed in the ITT were maintained following dose-reduction. 73.2% of CZP Completers had no radiographic progression at Week 128.ConclusionsIn patients with active RA despite MTX therapy, CZP was well tolerated, with no new safety signals identified. CZP provided sustained improvements in clinical outcomes for almost 5 years.

Trial registration

ClinicalTrials.gov, {"type":"clinical-trial","attrs":{"text":"NCT00160602","term_id":"NCT00160602"}}NCT00160602 and {"type":"clinical-trial","attrs":{"text":"NCT00160641","term_id":"NCT00160641"}}NCT00160641. Registered 8 September 2005.

Electronic supplementary material

The online version of this article (doi:10.1186/s13075-015-0767-2) contains supplementary material, which is available to authorized users.     

Prognostic molecular markers in pediatric liver disease – Are there any?

Pediatric liver disease (PLD) is a major cause of severe morbidity and prolonged hospitalizations in children. Stratifying patients in terms of prognosis remains challenging. The limited knowledge about molecular mechanisms causing and accompanying PLD remains the main obstacle in a search for reliable prognostic biomarkers. A systematic search of MEDLINE via PubMed and Embase via OVID was conducted on studies published between August 2007 and August 2017. Molecular markers with a prognostic potential in terms of survival, need for liver transplantation or disease progression/regression were selected. In general, identified studies were single center smaller case-control studies or case series with a low level of evidence and a high risk of bias. Only 23 studies comprising 898 patients could be included, mostly focusing on biliary atresia, non-alcoholic fatty liver disease, viral hepatitis, and LT; and markers related to morphogenesis and fibrosis. Furthermore, molecular markers in metabolic pathways and inflammation shown to be relevant, however requiring further validation. Hence, further biological and clinical studies are needed to gain greater molecular insight into PLD.     

Effectiveness of a Training Course for General Practice Nurses in Motivation Support in Type 2 Diabetes Care: A Cluster-Randomised Trial

Background

Type 2 diabetes is a common metabolic disease with the potential for prevention of complications. The prevention requires a high level of lasting actions from the patients, which may be burdensome. The aim of this trial was to evaluate the effectiveness of a training course for general practice nurses in motivation support at 18 months follow-up in the affiliated type 2 diabetes population.

Methods

Forty general practices with nurse-led diabetes consultations from the area of Aarhus, Denmark were randomised 1∶1 to either intervention or usual practice. Intervention practices were offered a 16-hour Self-determination theory - based course including communication training for general practice nurses delivered over 10 months. The affiliated diabetes populations (aged 40–74 years) were identified from registers (intervention n = 2,005; usual n = 2,029). Primary outcomes were register-based glycated haemoglobin (HbA_1c) -, total cholesterol levels, and well-being measured by the Problem Areas In Diabetes scale (PAID) and the mental component summary score, SF12 (SF12, mcs). Intention-to-treat analyses were performed. Predefined subgroups analyses were performed.

Results

The differences between the intervention- and the control practices’ mean HbA_1c and total cholesterol at follow-up adjusted for baseline values and clustering were respectively: −0.02%-points (95% CI: −0.11 to 0.07; p: 0.67); 0.08 mmol/l (95% CI: 0.01 to 0.15; p: 0.02). Differences in median scores adjusted for clustering were for PAID: 1.25; p = 0.31 and SF12, mcs: 0.99; p = 0.15. Women in intervention practices differed from women in usual practices on mean HbA_1c: −0.12%-points (−0.23 to −0.02; p = 0.02) and SF12, mcs: 2.6; p = 0.01.

Conclusions

Offering a training course for general practice nurses in applying the Self-determination theory in current type 2 diabetes care had no effect compared with usual practice measured by HbA_1c and total cholesterol levels and the well-being at 18 months of follow-up in a comprehensive register-based diabetes population. Subgroup analyses suggested a possible effect in women, which deserves further attention.

Trial Registration

ClinicalTrials.gov (Identifier {"type":"clinical-trial","attrs":{"text":"NCT01187069","term_id":"NCT01187069"}}NCT01187069).     

The hemopexin and O-glycosylated domains tune gelatinase B/MMP-9 bioavailability via inhibition and binding to cargo receptors

Gelatinase B/matrix metalloproteinase-9 (MMP-9), a key regulator and effector of immunity, contains a C-terminal hemopexin domain preceded by a unique linker sequence of approximately 64 amino acid residues. This linker sequence is demonstrated to be an extensively O-glycosylated (OG) domain with a compact three-dimensional structure. The OG and hemopexin domains have no influence on the cleavage efficiency of MMP-9 substrates. In contrast, the hemopexin domain contains a binding site for the cargo receptor low density lipoprotein receptor-related protein-1 (LRP-1). Furthermore, megalin/LRP-2 is identified as a new functional receptor for the hemopexin domain of MMP-9, able to mediate the endocytosis and catabolism of the enzyme. The OG domain is required to correctly orient the hemopexin domain for inhibition by TIMP-1 and internalization by LRP-1 and megalin. Therefore, the OG and hemopexin domains down-regulate the bioavailability of active MMP-9 and the interactions with the cargo receptors are proposed to be the original function of hemopexin domains in MMPs.     

Self-reported diseases and symptoms by rupture status among unselected Danish women with cosmetic silicone breast implants

Epidemiologic evidence does not support an association between silicone breast implants and connective tissue or other rheumatic diseases. However, a recent study has suggested that women with ruptured implants may be at increased risk of developing fibromyalgia. An analysis of adverse health outcomes according to breast implant rupture status was conducted in 238 unselected Danish women with cosmetic silicone breast implants. Ninety-two of the women had definite implant rupture, and 146 had intact implants as determined by magnetic resonance imaging. Before undergoing imaging, the women provided blood samples and completed a self-administered questionnaire. Women with ruptured implants overall, and the subgroup with extracapsular ruptures (n = 23), were compared with women with intact implants regarding a number of self-reported diseases and symptoms and the presence of specific autoantibodies, such as antinuclear antibodies, rheumatoid factor, and cardiolipin immunoglobulin G and M antibodies. Overall, there were no differences in the occurrence of self-reported diseases or symptoms or in the presence of autoantibodies between women with intact implants and women with ruptured implants, including extracapsular rupture. The only exception was capsular contracture, which was reported six times more frequently by women with extracapsular ruptures than by women with intact implants (OR, 6.3; 95 percent CI, 1.7 to 23.5). In conclusion, this study of unselected women with silicone breast implants could establish no association between silicone implant rupture and specific diseases or symptoms related to connective tissue disease or other rheumatic conditions, except for an excess of capsular contracture among women with extracapsular rupture.     

Quantitative proteomics suggests metabolic reprogramming during ETHE1 deficiency

Deficiency of mitochondrial sulfur dioxygenase (ETHE1) causes the severe metabolic disorder ethylmalonic encephalopathy, which is characterized by early‐onset encephalopathy and defective cytochrome C oxidase because of hydrogen sulfide accumulation. Although the severe systemic consequences of the disorder are becoming clear, the molecular effects are not well defined. Therefore, for further elucidating the effects of ETHE1‐deficiency, we performed a large scale quantitative proteomics study on liver tissue from ETHE1‐deficient mice. Our results demonstrated a clear link between ETHE1‐deficiency and redox active proteins, as reflected by downregulation of several proteins related to oxidation‐reduction, such as different dehydrogenases and cytochrome P450 (CYP450) members. Furthermore, the protein data indicated impact of the ETHE1‐deficiency on metabolic reprogramming through upregulation of glycolytic enzymes and by altering several heterogeneous ribonucleoproteins, indicating novel link between ETHE1 and gene expression regulation. We also found increase in total protein acetylation level, pointing out the link between ETHE1 and acetylation, which is likely controlled by both redox state and cellular metabolites. These findings are relevant for understanding the complexity of the disease and may shed light on important functions influenced by ETHE1 deficiency and by the concomitant increase in the gaseous mediator hydrogen sulfide. All MS data have been deposited in the ProteomeXchange with the dataset identifiers PXD002741 ( http://proteomecentral.proteomexchange.org/dataset/PXD002741 ) and PXD002742 ( http://proteomecentral.proteomexchange.org/dataset/PXD002741 ).