Cohort profile: the Food Chain Plus (FoCus) cohort.

The Food Chain Plus (FoCus) cohort was launched in 2011 for population-based research related to metabolic inflammation. To characterize this novel pathology in a comprehensive manner, data collection included multiple omics layers such as phenomics, microbiomics, metabolomics, genomics, and metagenomics as well as nutrition profiling, taste perception phenotyping and social network analysis. The cohort was set-up to represent a Northern German population of the Kiel region. Two-step recruitment included the randomised enrolment of participants via residents' registration offices and via the Obesity Outpatient Centre of the University Medical Center Schleswig-Holstein (UKSH). Hence, both a population- and metabolic inflammation- based cohort was created. In total, 1795 individuals were analysed at baseline. Baseline data collection took place between 2011 and 2014, including 63% females and 37% males with an age range of 18-83 years. The median age of all participants was 52.0 years [IQR: 42.5; 63.0 years] and the median baseline BMI in the study population was 27.7 kg/m2 [IQR: 23.7; 35.9 kg/m2]. In the baseline cohort, 14.1% of participants had type 2 diabetes mellitus, which was more prevalent in the subjects of the metabolic inflammation group (MIG; 31.8%). Follow-up for the assessment of disease progression, as well as the onset of new diseases with changes in subject's phenotype, diet or lifestyle factors is planned every 5 years. The first follow-up period was finished in 2020 and included 820 subjects.

Advanced glycation end products in human diabetic lens capsules.

Advanced glycation end products (AGEs) accumulate with age in human lens capsules. AGEs in lens capsules potentiate the transforming growth factor beta-2-mediated mesenchymal transition of lens epithelial cells, which suggests that they play a role in posterior capsule opacification after cataract surgery. We measured AGEs by liquid chromatography-mass spectrometry in capsulorhexis specimens obtained during cataract surgery from nondiabetic and diabetic patients with and without established retinopathy. Our data showed that the levels of most AGEs (12 out of 13 measured) were unaltered in diabetic patients and diabetic patients with retinopathy compared to nondiabetic patients. There was one exception: glucosepane, which was significantly higher in diabetic patients, both with (6.85 pmol/µmol OH-proline) and without retinopathy (8.32 pmol/µmol OH-proline), than in nondiabetic patients (4.01 pmol/µmol OH-proline). Our study provides an explanation for the similar incidence of posterior capsule opacification between nondiabetic and diabetic cataract patients observed in several studies.

Does Protein Glycation Impact on the Drought-Related Changes in Metabolism and Nutritional Properties of Mature Pea (Pisum sativum L.) Seeds?

Protein glycation is usually referred to as an array of non-enzymatic post-translational modifications formed by reducing sugars and carbonyl products of their degradation. The resulting advanced glycation end products (AGEs) represent a heterogeneous group of covalent adducts, known for their pro-inflammatory effects in mammals, and impacting on pathogenesis of metabolic diseases and ageing. In plants, AGEs are the markers of tissue ageing and response to environmental stressors, the most prominent of which is drought. Although water deficit enhances protein glycation in leaves, its effect on seed glycation profiles is still unknown. Moreover, the effect of drought on biological activities of seed protein in mammalian systems is still unstudied with respect to glycation. Therefore, here we address the effects of a short-term drought on the patterns of seed protein-bound AGEs and accompanying alterations in pro-inflammatory properties of seed protein in the context of seed metabolome dynamics. A short-term drought, simulated as polyethylene glycol-induced osmotic stress and applied at the stage of seed filling, resulted in the dramatic suppression of primary seed metabolism, although the secondary metabolome was minimally affected. This was accompanied with significant suppression of NF-kB activation in human SH-SY5Y neuroblastoma cells after a treatment with protein hydrolyzates, isolated from the mature seeds of drought-treated plants. This effect could not be attributed to formation of known AGEs. Most likely, the prospective anti-inflammatory effect of short-term drought is related to antioxidant effect of unknown secondary metabolite protein adducts, or down-regulation of unknown plant-specific AGEs due to suppression of energy metabolism during seed filling.

Pathways of the Maillard reaction under physiological conditions.

Initially investigated as a color formation process in thermally treated foods, nowadays, the relevance of the Maillard reaction in vivo is generally accepted. Many chronic and age-related diseases such as diabetes, uremia, atherosclerosis, cataractogenesis and Alzheimer's disease are associated with Maillard derived advanced glycation endproducts (AGEs) and α-dicarbonyl compounds as their most important precursors in terms of reactivity and abundance. However, the situation in vivo is very challenging, because Maillard chemistry is paralleled by enzymatic reactions which can lead to both, increases and decreases in certain AGEs. In addition, mechanistic findings established under the harsh conditions of food processing might not be valid under physiological conditions. The present review critically discusses the relevant α-dicarbonyl compounds as central intermediates of AGE formation in vivo with a special focus on fragmentation pathways leading to formation of amide-AGEs.

Comprehensive analysis of maillard protein modifications in human lenses: effect of age and cataract.

In human lens proteins, advanced glycation endproducts (AGEs) originate from the reaction of glycating agents, e.g., vitamin C and glucose. AGEs have been considered to play a significant role in lens aging and cataract formation. Although several AGEs have been detected in the human lens, the contribution of individual glycating agents to their formation remains unclear. A highly sensitive liquid chromatography-tandem mass spectrometry multimethod was developed that allowed us to quantitate 21 protein modifications in normal and cataractous lenses, respectively. N(6)-Carboxymethyl lysine, N(6)-carboxyethyl lysine, N(7)-carboxyethyl arginine, methylglyoxal hydroimidazolone 1, and N(6)-lactoyl lysine were found to be the major Maillard protein modifications among these AGEs. The novel vitamin C specific amide AGEs, N(6)-xylonyl and N(6)-lyxonyl lysine, but also AGEs from glyoxal were detected, albeit in minor quantities. Among the 21 modifications, AGEs from the Amadori product (derived from the reaction of glucose and lysine) and methylglyoxal were dominant.

Extending the spectrum of α-dicarbonyl compounds in vivo.

Maillard α-dicarbonyl compounds are known as central intermediates in advanced glycation end product (AGE) formation. Glucose is the primary source of energy for the human body, whereas l-threo-ascorbic acid (vitamin C) is an essential nutrient, involved in a variety of enzymatic reactions. Thus, the Maillard degradation of glucose and ascorbic acid is of major importance in vivo. To understand the complex mechanistic pathways of AGE formation, it is crucial to extend the knowledge on plasma concentrations of reactive key α-dicarbonyl compounds (e.g. 1-deoxyglucosone). With the present work, we introduce a highly sensitive LC-MS/MS multimethod for human blood plasma based on derivatization with o-phenylenediamine under acidic conditions. The impact of workup and reaction conditions, particularly of pH, was thoroughly evaluated. A comprehensive validation provided the limit of detection, limit of quantitation, coefficients of variation, and recovery rates. The method includes the α-dicarbonyls 1-deoxyglucosone, 3-deoxyglucosone, glucosone, Lederer's glucosone, dehydroascorbic acid, 2,3-diketogulonic acid, 1-deoxypentosone, 3-deoxypentosone, 3,4-dideoxypentosone, pentosone, 1-deoxythreosone, 3-deoxythreosone, threosone, methylglyoxal, glyoxal; the α-keto-carboxylic acids pyruvic acid and glyoxylic acid; and the dicarboxylic acid oxalic acid. The method was then applied to the analyses of 15 healthy subjects and 24 uremic patients undergoing hemodialysis. The comparison of the results revealed a clear shift in the product spectrum. In most cases, the plasma levels of target analytes were significantly higher. Thus, this is the first time that a complete spectrum of α-dicarbonyl compounds relevant in vivo has been established. The results provide further insights into the chemistry of AGE formation and will be helpful to find specific markers to differentiate between the various precursors of glycation.

High cut-off dialysis in chronic haemodialysis patients.

BACKGROUND: Haemodialysis patients suffer from chronic systemic inflammation and high incidence of cardiovascular disease. One cause for this may be the failure of diseased kidneys to eliminate immune mediators. Current haemodialysis treatment achieves insufficient elimination of proteins in the molecular weight range 15-45 kD. Thus, high cut-off dialysis might improve the inflammatory state. DESIGN: In this randomized crossover trial, 43 haemodialysis patients were treated for 3 weeks with high cut-off or high-flux dialysis. Inflammatory plasma mediators, monocyte subpopulation distribution and leucocyte gene expression were quantified. RESULTS: High cut-off dialysis supplemented by a low-flux filter did not influence the primary end-point, expression density of CD162 on monocytes. Nevertheless, treatment reduced multiple immune mediators in plasma. Such reduction proved - at least for some markers - to be a sustained effect over the interdialytic interval. Thus, for example, soluble TNF-receptor 1 concentration predialysis was reduced from median 13·3 (IQR 8·9-17·2) to 9·7 (IQR 7·5-13·2) ng/mL with high cut-off while remaining constant with high-flux treatment. The expression profile of multiple proinflammatory genes in leucocytes was significantly dampened. Treatment was well tolerated although albumin losses in high cut-off dialysis would be prohibitive against long-term use. CONCLUSIONS: The study shows for the first time that a dampening effect of high cut-off dialysis on systemic inflammation is achievable. Earlier studies had failed due to short study duration or insufficient dialysis efficacy. Removal of soluble mediators from the circulation influences cellular activation levels in leucocytes. Continued development of less albumin leaky membranes with similar cytokine elimination is justified.

Accumulation of advanced glycation end products in the rabbit blastocyst under maternal diabetes.

Diabetes mellitus (DM) during pregnancy is one of the leading causes of perinatal morbidity and birth defects. The mechanism by which maternal hyperglycemia, the major teratogenic factor, induces embryonic malformations remains unclear. Advanced glycation end products (AGEs) are known to accumulate during the course of DM and contribute to the development of diabetic complications. Employing a diabetic rabbit model, we investigated the influence of maternal hyperglycemia during the preimplantation period on AGE formation (pentosidine, argpyrimidine, and N(ϵ)-carboxymethyllysine (CML)) in the reproductive tract and the embryo itself. As a consequence of type 1 DM, the AGE levels in blood plasma increased up to 50%, correlating closely with an AGE accumulation in the endometrium of diabetic females. Embryos from diabetic mothers had increased protein-bound CML levels and showed enhanced fluorescent signals for AGE-specific fluorescence in the blastocyst cavity fluid (BCF). The quantification of CML by HPLC-mass spectrometry (MS/MS) showed a higher amount of soluble CML in the BCF of blastocysts from diabetic rabbits (0.26±0.05 µmol/l) compared with controls (0.18±0.02 µmol/l). The high amount of AGEs in blastocysts from diabetic mothers correlates positively with an increased AGER (receptor for AGE (RAGE)) mRNA expression. Our study gives alarming insights into the consequences of poorly controlled maternal diabetes for AGE formation in the embryo. Maternal hyperglycemia during the preimplantation period is correlated with an increase in AGE formation in the uterine environment and the embryo itself. This may influence the development of the embryo through increased AGE-mediated cellular stress by RAGEs.

Viability and adaptation potential of indigenous microorganisms from natural gas field fluids in high pressure incubations with supercritical CO2.

Carbon Capture and Storage (CCS) is currently under debate as large-scale solution to globally reduce emissions of the greenhouse gas CO2. Depleted gas or oil reservoirs and saline aquifers are considered as suitable reservoirs providing sufficient storage capacity. We investigated the influence of high CO2 concentrations on the indigenous bacterial population in the saline formation fluids of a natural gas field. Bacterial community changes were closely examined at elevated CO2 concentrations under near in situ pressures and temperatures. Conditions in the high pressure reactor systems simulated reservoir fluids i) close to the CO2 injection point, i.e. saturated with CO2, and ii) at the outer boundaries of the CO2 dissolution gradient. During the incubations with CO2, total cell numbers remained relatively stable, but no microbial sulfate reduction activity was detected. After CO2 release and subsequent transfer of the fluids, an actively sulfate-respiring community was re-established. The predominance of spore-forming Clostridiales provided evidence for the resilience of this taxon against the bactericidal effects of supercritical (sc)CO2. To ensure the long-term safety and injectivity, the viability of fermentative and sulfate-reducing bacteria has to be considered in the selection, design, and operation of CCS sites.

Population-level coding of avoidance learning in medial prefrontal cortex.

The medial prefrontal cortex (mPFC) has been proposed to link sensory inputs and behavioral outputs to mediate the execution of learned behaviors. However, how such a link is implemented has remained unclear. To measure prefrontal neural correlates of sensory stimuli and learned behaviors, we performed population calcium imaging during a new tone-signaled active avoidance paradigm in mice. We developed an analysis approach based on dimensionality reduction and decoding that allowed us to identify interpretable task-related population activity patterns. While a large fraction of tone-evoked activity was not informative about behavior execution, we identified an activity pattern that was predictive of tone-induced avoidance actions and did not occur for spontaneous actions with similar motion kinematics. Moreover, this avoidance-specific activity differed between distinct avoidance actions learned in two consecutive tasks. Overall, our results are consistent with a model in which mPFC contributes to the selection of goal-directed actions by transforming sensory inputs into specific behavioral outputs through distributed population-level computations.

Neutrophil extracellular traps in CSF and serum of dogs with steroid-responsive meningitis-arteritis.

In steroid-responsive meningitis-arteritis (SRMA), inflammatory dysregulation is driven by neutrophilic granulocytes resulting in purulent leptomeningitis. Neutrophils can generate neutrophil extracellular traps (NET). Uncontrolled NET-formation or impaired NET-clearance evidently cause tissue and organ damage resulting in immune-mediated diseases. The aim of the study was to verify that NET-formation is detectable in ex vivo samples of acute diseased dogs with SRMA by visualizing and measuring NET-markers in serum and cerebrospinal fluid (CSF) samples. CSF-samples of dogs with acute SRMA (n = 5) and in remission (n = 4) were examined using immunofluorescence (IF)-staining of DNA-histone-1-complexes, myeloperoxidase and citrullinated Histone H3 (H3Cit). Immunogold-labeling of H3Cit and neutrophil elastase followed by transmission electron microscopy (TEM) were used to determine ultrastructural NET-formation in the CSF of one exemplary dog. H3Cit-levels and DNase-activity were measured in CSF and serum samples using an H3Cit-ELISA and a DNase-activity-assay, respectively in patients with the following diseases: acute SRMA (n = 34), SRMA in remission (n = 4), bacterial encephalitis (n = 3), meningioma with neutrophilic inflammation (n = 4), healthy dogs (n = 6). NET-formation was detectable with IF-staining in n = 3/5 CSF samples of dogs with acute SRMA but were not detectable during remission. Vesicular NET-formation was detectable in one exemplary dog using TEM. DNase-activity was significantly reduced in dogs suffering from acute SRMA compared to healthy control group (p < 0.0001). There were no statistical differences of H3Cit levels in CSF or serum samples of acute diseased dogs compared to dogs under treatment, dogs suffering from meningioma or bacterial encephalitis or the healthy control group. Our findings demonstrate that NET-formation and insufficient NET-clearance possibly drive the immunologic dysregulation and complement the pathogenesis of SRMA. The detection of NETs in SRMA offers many possibilities to explore the aetiopathogenetic influence of this defence mechanism of the innate immune system in infectious and non-infectious canine neuropathies.

Tuning Human Serum Albumin (HSA) Hydrogels through Albumin Glycation.

The changes of technological properties of albumin-based hydrogels induced by increasing degrees of post-translational modification of the protein are reported. Maillard-type modification of amino acids arginine and lysine of albumin is achieved through glyoxal as an α-dicarbonyl compound. The degrees of modification are fine-tuned using different molar ratios of glyoxal. Hydrogels are thermally induced by heating highly concentrated precursor solutions above the protein's denaturation temperature. While the post-translational modifications are determined and quantified with mass spectrometry, continuous-wave (CW) electron paramagnetic resonance (EPR) spectroscopy shed light on the protein fatty acid binding capacity and changes thereof in solution and in the gel state. The viscoelastic behavior is characterized as a measure of the physical strength of the hydrogels. On the nanoscopic level, the modified albumins in low concentration solution reveal lower binding capacities with increasing degrees of modification. On the contrary, in the gel state, the binding capacity remains constant at all degrees of modifications. This indicates that the loss of fatty acid binding capacity for individual albumin molecules is partially compensated by new binding sites in the gel state, potentially formed by modified amino acids. Such, albumin glycation offers a fine-tuning method of technological and nanoscopic properties of these gels.

Current definition, diagnosis, and treatment of canine and feline idiopathic vestibular syndrome.

Idiopathic vestibular syndrome (IVS) is one of the most common neurological disorders in veterinary medicine. However, its diagnosis and treatment varies between publications. The aim of the current study was to gather experts' opinion about IVS definition, diagnosis, and treatment. An online-survey was used to assess neurology specialists' opinion about the definition, diagnosis and treatment of IVS. The study demonstrated that the definition, diagnosis, and treatment of IVS are largely consistent worldwide, with the EU prioritising less frequently advanced imaging and more often otoscopy to rule out other diseases. IVS was defined by most specialists as an acute to peracute, improving, non-painful peripheral vestibular disorder that often affects cats of any age and geriatric dogs. Regarding diagnosis, a detailed neurological examination and comprehensive blood tests, including thyroid values, blood pressure, and otoscopic examination, was seen as crucial. A thorough workup may also involve MRI and CSF analysis to rule out other causes of vestibular dysfunction. Treatment of IVS typically involved intravenous fluid therapy and the use of an antiemetic, with maropitant once daily being the preferred choice among specialists. Antinausea treatment was considered, however, only by a handful specialists. This survey-based study provides valuable insights from neurology experts and highlights areas that require further research to bridge the gap between theory and practice.

Molecular basis of maillard amide-advanced glycation end product (AGE) formation in vivo.

The Maillard reaction in vivo entails alteration of proteins or free amino acids by non-enzymatic glycation or glycoxidation. The resulting modifications are called advanced glycation end products (AGEs) and play a prominent role in various pathologies, including normoglycemic uremia. Recently, we established a new class of lysine amide modifications in vitro. Now, human plasma levels of the novel amide-AGEs N(6)-acetyl lysine, N(6)-formyl lysine, N(6)-lactoyl lysine, and N(6)-glycerinyl lysine were determined by means of LC-MS/MS. They were significantly higher in uremic patients undergoing hemodialysis than in healthy subjects. Model reactions with N(1)-t-butoxycarbonyl-lysine under physiological conditions confirmed 1-deoxy-d-erythro-hexo-2,3-diulose as an immediate precursor. Because formation of N(6)-formyl lysine from glucose responded considerably to the presence of oxygen, glucosone was identified as another precursor. Comparison of the in vivo results with the model experiments enabled us to elucidate possible formation pathways linked to Maillard chemistry. The results strongly suggest a major participation of non-enzymatic Maillard mechanisms on amide-AGE formation pathways in vivo, which, in the case of N(6)-acetyl lysine, parallels enzymatic processes.

Canine muscle cell culture and consecutive patch-clamp measurements - a new approach to characterize muscular diseases in dogs.

BACKGROUND: The recognition of functional muscular disorders, (e.g. channelopathies like Myotonia) is rising in veterinary neurology. Morphologic (e.g. histology) and even genetic based studies in these diseases are not able to elucidate the functional pathomechanism. As there is a deficit of knowledge and skills considering this special task, the aim of the current pilot study was to develop a canine muscle cell culture system derived from muscle biopsies of healthy client-owned dogs, which allows sampling of the biopsies under working conditions in the daily veterinary practise. RESULTS: Muscular biopsies from 16 dogs of different age and breed were taken during standard surgical procedures and were stored for one to three days at 4°C in a transport medium in order to simulate shipping conditions. Afterwards biopsies were professionally processed, including harvesting of satellite cells, inducing their proliferation, differentiating them into myotubes and recultivating myotubes after long-term storage in liquid nitrogen. Myogenic origin of cultured cells was determined by immunofluorescence, immunohistology and by their typical morphology after inducing differentiation. Subsequent to the differentiation into myotubes feasibility of patch-clamp recordings of voltage gated ion channels was successfully. CONCLUSION: We have developed a canine muscle cell culture system, which allows sampling of biopsies from young and old dogs of different breeds under practical conditions. Patch clamp measurements can be carried out with the cultured myotubes demonstrating potential of these cells as source for functional research.

Glycation Alters the Fatty Acid Binding Capacity of Human Serum Albumin.

Glycation significantly alters the physicochemical and biofunctional properties of proteins in foods and in vivo. In the present study, human serum albumin (HSA) as the major transporter of fatty acids was modified with glyoxal under physiological conditions. Reversibly albumin-bound glyoxal was removed, and advanced glycation end products were quantitated by liquid chromatography-tandem mass spectrometry (LC-MS/MS). The total modification of protein-bound lysine and arginine residues reached up to 4.2 and 9.6%, respectively. The impact of these modifications on the transport capacity of long-chain fatty acids was characterized by spin-labeled fatty acid probes via electron paramagnetic resonance spectroscopy. With increasing degree of glycation, the equivalence of the seven binding sites of native HSA with a dissociation constant of 0.74 ± 0.09 µM was set off with only the three high-affinity sites 2, 4, and 5 remaining (0.46 ± 0.07 µM). The other four sites were shifted to low affinities with significantly higher dissociation constants (1.32 ± 0.35 µM). Tryptic peptide mapping enabled us to relate these findings to molecular changes at specific binding sites. Modification hotspots identified were lysine 351, 286, 159 and arginine 144, 485, 117. Further investigation of plasma protein samples of uremic patients vs healthy controls gave first insights into the in vivo situation.

Validation of the Simplified Disease Activity Index (SDAI) with a quick quantitative C-reactive protein assay (SDAI-Q) in patients with rheumatoid arthritis: a prospective multicenter cross-sectional study.

Objectives: The Simplified Disease Activity Index (SDAI) is a recommended composite score for assessing the remission status in patients with rheumatoid arthritis (RA). However, determination of C-reactive protein (CRP) levels takes several hours and sometimes days and limits the use of the SDAI in the clinical setting. The aim of this study was to validate the SDAI using a quick quantitative C-reactive protein (qCRP) assay (as SDAI-Q) in RA patients. Design: This is a multicenter, prospective, cross-sectional pilot study in RA patients. Methods: Adult patients (⩾18 years) with a clinical diagnosis of RA were recruited between January 2020 and September 2020 from five rheumatologic centers located in Berlin, Germany. SDAI, SDAI-Q, Clinical Disease Activity Index (CDAI), and DAS28 scores comprising CRP, qCRP, or erythrocyte sedimentation rate (ESR) were calculated. The agreement of disease activity categories was analyzed using cross tabulations and weighted Cohen's kappa. The agreement of numerical values was analyzed with Bland-Altman plots and intraclass correlation coefficients (ICCs). Results: Overall, 100 RA patients were included in the statistical analysis. The mean value of qCRP (7.89 ± 16.98 mg/l) was slightly higher than that of routine laboratory CRP (6.97 ± 15.02 mg/l). Comparing SDAI and SDAI-Q, all patients were assigned to identical disease activity categories. Agreement of disease activity categories by CDAI and SDAI/SDAI-Q was observed in 93% with a weighted Cohen's kappa of 0.929 (95% confidence interval (CI) = 0.878; 0.981). Conclusion: The SDAI-Q showed an absolute agreement regarding the assignment of disease activity categories in comparison with the conventional SDAI. Therefore, the SDAI-Q may facilitate the application of a treat-to-target concept in clinical trials and clinical routine as a quickly available disease activity score incorporating CRP as an objective parameter.

Validation of the ASDAS with a quick quantitative CRP assay (ASDAS-Q) in patients with axial SpA: a prospective multicentre cross-sectional study.

Objectives: The objective of the study was to validate the Ankylosing Spondylitis Disease Activity Score (ASDAS) based on a quick quantitative C-reactive protein (qCRP) assay (ASDAS-Q) in a multicentre, prospective, cross-sectional study in patients with axial spondyloarthritis (axial SpA). Methods: Disease activity assessment was performed in prospectively recruited patients with axial SpA. Routine laboratory CRP was determined in the central laboratory of each study centre, while quick qCRP and erythrocyte sedimentation rate (ESR) were measured locally. Consequently, ASDAS-CRP, ASDAS-Q using the qCRP and ASDAS-ESR were calculated. The absolute agreement on the disease activity category ascertainment was analysed with cross-tabulations and weighted Cohen's kappa. Bland-Altman plots and intraclass correlation coefficients (ICCs) were used to analyse the criterion validity. Results: Overall, 251 axial SpA patients were included in the analysis. The mean qCRP value (6.34 ± 11.13 mg/l) was higher than that of routine laboratory CRP (5.26 ± 9.35 mg/l). The ICC for routine laboratory CRP versus qCRP was 0.985 [95% confidence interval (CI): 0.972-0.991]. Comparing ASDAS-Q with ASDAS-CRP, 242 of 251 (96.4%) patients were assigned to the same disease activity categories with a weighted Cohen's kappa of 0.966 (95% CI: 0.943-0.988) and ICC of 0.997 (95% CI: 0.994-0.999). Conclusions: ASDAS-Q showed an almost perfect agreement with ASDAS-CRP in the assignment to specific disease activity categories. Consequently, ASDAS-Q using the qCRP value can be applied as an accurate and quickly available alternative to ASDAS-CRP, thus facilitating the implementation of the treat-to-target concept in clinical trials and clinical routine.

Evaluation of the Disease Activity index for PSoriatic Arthritis (DAPSA) with a quick quantitative C reactive protein assay (Q-DAPSA) in patients with psoriatic arthritis: a prospective multicentre cross-sectional study.

OBJECTIVES: This study aimed to evaluate the Disease Activity index for PSoriatic Arthritis (DAPSA) based on a quick quantitative C reactive protein (qCRP) assay (Q-DAPSA) in a multicentre, prospective, cross-sectional study in patients with psoriatic arthritis (PsA). METHODS: The assessment of prospectively recruited study patients included joint examination and patient reported outcome (PRO) measures (patient global assessment, patient pain assessment). Following, the DAPSA based on a routine laboratory CRP measurement, Q-DAPSA and clinical DAPSA (cDAPSA) were calculated. Cross-tabulations and weighted Cohen's kappa were performed to analyse the agreement of disease activity categories. Bland-Altman plots and intraclass correlation coefficients were used to determine the agreement of numerical values regarding CRP and qCRP as well as different disease activity scores. RESULTS: Altogether, 104 patients with PsA could be included in the statistical analysis. With Q-DAPSA, 102 of 104 (98.1%) patients achieved identical disease activity categories in comparison to DAPSA with a weighted Cohen's kappa of 0.980 (95% CI: 0.952 to 1.000). The agreement between DAPSA and cDAPSA was slightly lower with identical disease activity categories seen in 97 of 104 (93.3%) of patients and with a weighted Cohen's kappa of 0.932 (95% CI 0.885 to 0.980). CONCLUSIONS: The Q-DAPSA showed an almost perfect agreement with the conventional DAPSA regarding identical disease activity categories. Thus, the Q-DAPSA can be used as a timely available disease activity score in patients with PsA with the additional benefit of CRP involvement. Consequently, the Q-DAPSA could facilitate the implementation of the treat-to-target concept in clinical routine and clinical trials.

Hydroimidazolone modification of human alphaA-crystallin: Effect on the chaperone function and protein refolding ability.

AlphaA-crystallin is a molecular chaperone; it prevents aggregation of denaturing proteins. We have previously demonstrated that upon modification by a metabolic alpha-dicarbonyl compound, methylglyoxal (MGO), alphaA-crystallin becomes a better chaperone. AlphaA-crystallin also assists in refolding of denatured proteins. Here, we have investigated the effect of mild modification of alphaA-crystallin by MGO (with 20-500 microM) on the chaperone function and its ability to refold denatured proteins. Under the conditions used, mildly modified protein contained mostly hydroimidazolone modifications. The modified protein exhibited an increase in chaperone function against thermal aggregation of beta(L)- and gamma-crystallins, citrate synthase (CS), malate dehydrogenase (MDH) and lactate dehydrogenase (LDH) and chemical aggregation of insulin. The ability of the protein to assist in refolding of chemically denatured beta(L)- and gamma-crystallins, MDH and LDH, and to prevent thermal inactivation of CS were unchanged after mild modification by MGO. Prior binding of catalytically inactive, thermally denatured MDH or the hydrophobic probe, 2-p-toluidonaphthalene-6-sulfonate (TNS) abolished the ability of alphaA-crystallin to assist in the refolding of denatured MDH. However, MGO modification of chaperone-null TNS-bound alphaA-crystallin resulted in partial regain of the chaperone function. Taken together, these results demonstrate that: 1) hydroimidazolone modifications are sufficient to enhance the chaperone function of alphaA-crystallin but such modifications do not change its ability to assist in refolding of denatured proteins, 2) the sites on the alphaA-crystallin responsible for the chaperone function and refolding are the same in the native alphaA-crystallin and 3) additional hydrophobic sites exposed upon MGO modification, which are responsible for the enhanced chaperone function, do not enhance alphaA-crystallin's ability to refold denatured proteins.