Biophysical and enzymatic properties of aminoglycoside adenylyltransferase AadA6 from Pseudomonas aeruginosa

AbstractThe gene coding for the aminoglycoside adenylyltransferase (aadA6) from a clinical isolate of Pseudomonas aeruginosa was cloned and expressed in Escherichia coli strain BL21(DE3)pLysS. The overexpressed enzyme (AadA6, 281 amino-acid residues) and a carboxy-terminal truncated variant molecule ([1-264]AadA6) were purified to near homogeneity and characterized. Light scattering experiments conducted under low ionic strength supported equilibrium between monomeric and homodimeric arrangements of the enzyme subunits. Circular Dichroism spectropolarimetry indicated a close structural relation to adenylate kinases. Both forms modified covalently the aminoglycosides streptomycin and spectinomycin. The enzyme required at least 5mM MgCl2 for normal Michaelis–Menten kinetics. Streptomycin exhibited a strong substrate inhibition effect at 1mM MgCl2. The truncated 17 residues at the C-terminus have little influence on protein folding, whereas they have a positive effect on the enzymic activity and stabilize dimers at high protein concentrations (>100μM). Homology modelling and docking based on known crystal structures yielded models of the central ternary complex of monomeric AadA6 with ATP and streptomycin or spectinomycin

Changes in hand and generalised bone mineral density in patients with recent-onset rheumatoid arthritis

Objectives: To evaluate changes in bone mineral density (BMD) in the hands, hip and spine after 1 and 2 years of follow-up, in relation to antirheumatic and antiresorptive therapies and disease and demographic variables in patients with recent-onset rheumatoid arthritis ( RA). Methods: Changes in BMD measured in metacarpals 2-4 by digital x-ray radiogrammetry and in the hip and spine by dual energy x-ray absorptiometry were assessed at baseline and after 1 and 2 years of follow-up in 218 patients with recent-onset RA from the BeSt study, who received one of four treatment strategies: sequential monotherapy ( group 1); step-up combination therapy ( group 2); initial combination therapy with tapered high-dose prednisone ( group 3); or initial combination therapy with infliximab (group 4). Results: After 1 and 2 years, there was significant BMD loss in all locations, with significantly greater BMD loss in the hands than generalised BMD loss in the hip and spine. Initial combination therapy with prednisone or infliximab were associated with less hand BMD loss compared with initial monotherapy after 1 and 2 years (-0.9 and -1.6%, -0.6 and -1.4%, -1.7 and -3.3%, and -2.6 and -3.6% for group 4-1 after 1 and 2 years, overall p = 0.001 and p = 0.014, respectively). Progression in erosions was independently associated with increased BMD loss both in the hands and hip after 1 year. The use of bisphosphonates protected only against generalised BMD loss in the hip and spine. Conclusions: The association between joint damage progression and both hand and generalised BMD loss in RA suggests common pathways between these processes, with hand BMD loss occurring earlier in the disease course than generalised BMD los

Body mass index and treatment survival in patients with RA starting treatment with TNF alpha-inhibitors: long-term follow-up in the real-life METEOR registry

Objectives To study whether there is an association between body mass index (BMI) category and survival of various tumour necrosis factor inhibitors (TNFi) in rheumatoid arthritis (RA) patients in a real-life longitudinal international registry.Methods Data from 5230 patients with RA starting treatment with any TNFi were selected from the METEOR registry. Patients were divided into six BMI categories: 3.7% underweight, BMI40 kg/m(2). Time on treatment in the different BMI categories was compared for all TNFi combined and for the infliximab, adalimumab and etanercept separately, using Kaplan-Meier curves and Cox regression analyses. Cox regression analyses were adjusted for potential confounders, with follow-up censored at 5000 days.Results Patients in obesity class II (HR 1.28, 95% CI 1.06 to 1.54) and III (HR 1.67, 95% CI 1.29 to 2.18) and underweight patients (HR 1.30, 95% CI 1.07 to 1.58) showed statistically significantly shorter TNFi survival than normal weight patients. The effect in underweight patients was strongest for infliximab (HR 1.82, 95% CI 1.20 to 2.76), the effect in overweight patients was strongest for infliximab (category II (HR 1.49, 95% CI 0.98 to 2.26); category III (HR 1.46, 95% CI 0.79 to 2.71)) and etanercept (category II (HR 1.27 95% CI 0.98 to 1.65); category III (HR 1.79, 95% CI 1.25 to 2.55)). No significant effect modification from reported pain was found.Conclusion Both underweight and overweight patients discontinued TNFi treatment earlier than normal weight patients, without evidence of reported pain as the main determinant. It remains uncertain what determines TNFi survival in individual patients.Pathophysiology and treatment of rheumatic disease

Clinical and radiological efficacy of initial vs delayed treatment with infliximab plus methotrexate in patients with early rheumatoid arthritis

= 6 months, IFX was tapered and finally stopped. We aimed to correct for allocation bias using propensity scores. Functional ability was measured by the Health Assessment Questionnaire (HAQ), radiological progression by Sharp/van der Heijde scoring (SHS). Results: Baseline differences between the initial and delayed groups were no longer significant after propensity score adjustment. At 3 years after baseline, patients treated with initial MTX+IFX experienced more improvement in HAQ over time and were less likely to have SHS progression than patients treated with delayed MTX+IFX (p = 0.034). At 2 years after IFX initiation, more patients in the initial group compared with the delayed group could discontinue IFX after a good response (56% vs 29%, p = 0.008). Conclusions: The results of this post hoc analysis suggest that using MTX+IFX as initial treatment for patients with recent onset RA is more effective than reserving MTX+IFX for patients who failed on traditional DMARDs, with more HAQ improvement over time, more IFX discontinuation and less progression of joint damag

Prospective study into COVID-19-like symptoms in patients with and without immune-mediated inflammatory diseases or immunomodulating drugs

Cellular mechanisms in basic and clinical gastroenterology and hepatolog

Earlier chronotype in patients with rheumatoid arthritis

Health and self-regulatio

Age affects joint space narrowing in patients with early active rheumatoid arthritis

Background: Joint space narrowing ( JSN) in rheumatoid arthritis (RA) may be a manifestation of (primary) osteoarthritis becoming more prominent with age. We investigated the severity and predictors of JSN progression among different age groups. Methods: 10-year follow-up data of the BeSt study, a randomised controlled treat-to-target trial in early RA were used. Annual X-rays of hands and feet were scored using the Sharp/van der Heijde score (SHS). Subgroups were defined by age at baseline: 55, 40<55 and <40 years. JSN progression predictors were assessed by Poisson regression. Results: Baseline JSN scores (median (IQR)) were igher in patients 55 (2.0 (0.0-6.0)) compared with the other age groups: 1.0 (0.0-3.0) 40<55 and 0.3 (0.0-3.0) <40, p<0.001. After 10 years, total JSN and SHS were similar in all age groups. In patients 55 the mean erythrocyte sedimentation rate (ESR) over time (relative risk 1.02 (95% CI 1.00 to 1.03)

Feasibility of tailored treatment based on risk stratification in patients with early rheumatoid arthritis

Introduction: Personalized medicine is the holy grail of medicine. The EULAR recommendations for the management of rheumatoid arthritis (RA) support differential treatment between patients with baseline characteristics suggestive of a non-poor prognosis (non-PP) or poor prognosis (PP) (presence of autoantibodies, a high inflammatory activity and damage on radiographs). We aimed to determine which prognostic risk groups benefit more from initial monotherapy or initial combination therapy. Methods: 508 patients were randomized t

Earlier chronotype in patients with rheumatoid arthritis (Jan, 10.1007/s10067-020-05546-x, 2021)

A correction to this paper has been published:Pathophysiology and treatment of rheumatic disease

Correction to: Earlier chronotype in patients with rheumatoid arthritis

Health and self-regulatio