The meiotic chromosome axis plays key roles in meiotic chromosome organization and recombination, yet the underlying protein components of this structure are highly diverged. Here, we show that 'axis ...core proteins' from budding yeast (Red1), mammals (SYCP2/SYCP3), and plants (ASY3/ASY4) are evolutionarily related and play equivalent roles in chromosome axis assembly. We first identify 'closure motifs' in each complex that recruit meiotic HORMADs, the master regulators of meiotic recombination. We next find that axis core proteins form homotetrameric (Red1) or heterotetrameric (SYCP2:SYCP3 and ASY3:ASY4) coiled-coil assemblies that further oligomerize into micron-length filaments. Thus, the meiotic chromosome axis core in fungi, mammals, and plants shares a common molecular architecture, and likely also plays conserved roles in meiotic chromosome axis assembly and recombination control.
Changes induced by perturbed aerosol conditions in moderately deep mixed-phase convective clouds
(cloud top height ∼ 5 km)
developing along sea-breeze convergence
lines are investigated with ...high-resolution numerical model simulations. The
simulations utilise the newly developed Cloud–AeroSol Interacting Microphysics (CASIM) module for
the Unified Model (UM), which allows for the representation of the two-way interaction between cloud and
aerosol fields. Simulations are evaluated against observations collected during the COnvective
Precipitation Experiment (COPE) field campaign over the southwestern peninsula of the UK in 2013.
The simulations compare favourably with observed thermodynamic profiles, cloud base cloud droplet
number concentrations (CDNC), cloud depth, and radar reflectivity statistics. Including the
modification of aerosol fields by cloud microphysical processes improves the correspondence with
observed CDNC values and spatial variability, but reduces the agreement with observations for
average cloud size and cloud top height. Accumulated precipitation is suppressed for higher-aerosol conditions before clouds become organised
along the sea-breeze convergence lines. Changes in precipitation are smaller in simulations with
aerosol processing. The precipitation suppression is due to less efficient precipitation production
by warm-phase microphysics, consistent with parcel model predictions. In contrast, after convective cells organise along the sea-breeze convergence zone, accumulated
precipitation increases with aerosol concentrations. Condensate production increases with the
aerosol concentrations due to higher vertical velocities in the convective cores and higher cloud
top heights. However, for the highest-aerosol scenarios, no further increase in the condensate
production occurs, as clouds grow into an upper-level stable layer. In these cases, the reduced
precipitation efficiency (PE) dominates the precipitation response and no further precipitation
enhancement occurs. Previous studies of deep convective clouds have related larger vertical
velocities under high-aerosol conditions to enhanced latent heating from freezing.
In the presented simulations changes in latent heating above the 0∘C are negligible, but latent
heating from condensation increases with aerosol concentrations. It is hypothesised that this
increase is related to changes in the cloud field structure reducing the mixing of environmental air
into the convective core. The precipitation response of the deeper mixed-phase clouds along well-established convergence lines
can be the opposite of predictions from parcel models. This occurs when clouds interact with a
pre-existing thermodynamic environment and cloud field structural changes occur that are not
captured by simple parcel model approaches.
Juvenile idiopathic arthritis (JIA) is a heterogeneous group of conditions unified by the presence of chronic childhood arthritis without an identifiable cause. Systemic JIA (sJIA) is a rare form of ...JIA characterised by systemic inflammation. sJIA is distinguished from other forms of JIA by unique clinical features and treatment responses that are similar to autoinflammatory diseases. However, approximately half of children with sJIA develop destructive, long-standing arthritis that appears similar to other forms of JIA. Using genomic approaches, we sought to gain novel insights into the pathophysiology of sJIA and its relationship with other forms of JIA.
We performed a genome-wide association study of 770 children with sJIA collected in nine countries by the International Childhood Arthritis Genetics Consortium. Single nucleotide polymorphisms were tested for association with sJIA. Weighted genetic risk scores were used to compare the genetic architecture of sJIA with other JIA subtypes.
The major histocompatibility complex locus and a locus on chromosome 1 each showed association with sJIA exceeding the threshold for genome-wide significance, while 23 other novel loci were suggestive of association with sJIA. Using a combination of genetic and statistical approaches, we found no evidence of shared genetic architecture between sJIA and other common JIA subtypes.
The lack of shared genetic risk factors between sJIA and other JIA subtypes supports the hypothesis that sJIA is a unique disease process and argues for a different classification framework. Research to improve sJIA therapy should target its unique genetics and specific pathophysiological pathways.
To describe clinical outcomes of juvenile idiopathic arthritis (JIA) in a prospective inception cohort of children managed with contemporary treatments.
Children newly diagnosed with JIA at 16 ...Canadian paediatric rheumatology centres from 2005 to 2010 were included. Kaplan-Meier survival curves for each JIA category were used to estimate probability of ever attaining an active joint count of 0, inactive disease (no active joints, no extraarticular manifestations and a physician global assessment of disease activity <10 mm), disease remission (inactive disease >12 months after discontinuing treatment) and of receiving specific treatments.
In a cohort of 1104 children, the probabilities of attaining an active joint count of 0 exceeded 78% within 2 years in all JIA categories. The probability of attaining inactive disease exceeded 70% within 2 years in all categories, except for RF-positive polyarthritis (48%). The probability of discontinuing treatment at least once was 67% within 5 years. The probability of attaining remission within 5 years was 46-57% across JIA categories except for polyarthritis (0% RF-positive, 14% RF-negative). Initial treatment included joint injections and non-steroidal anti-inflammatory drugs for oligoarthritis, disease-modifying antirheumatic drugs (DMARDs) for polyarthritis and systemic corticosteroids for systemic JIA.
Most children with JIA managed with contemporary treatments attain inactive disease within 2 years of diagnosis and many are able to discontinue treatment. The probability of attaining remission within 5 years of diagnosis is about 50%, except for children with polyarthritis.
Joint inflammation is the common feature underlying juvenile idiopathic arthritis (JIA). Clinicians recognize patterns of joint involvement currently not part of the International League of ...Associations for Rheumatology (ILAR) classification. Using unsupervised machine learning, we sought to uncover data-driven joint patterns that predict clinical phenotype and disease trajectories.
We analyzed prospectively collected clinical data, including joint involvement using a standard 71-joint homunculus, for 640 discovery patients with newly diagnosed JIA enrolled in a Canada-wide study who were followed serially for five years, treatment-naïve except for nonsteroidal anti-inflammatory drugs (NSAIDs) and diagnosed within one year of symptom onset. Twenty-one patients had systemic arthritis, 300 oligoarthritis, 125 rheumatoid factor (RF)-negative polyarthritis, 16 RF-positive polyarthritis, 37 psoriatic arthritis, 78 enthesitis-related arthritis (ERA), and 63 undifferentiated arthritis. At diagnosis, we observed global hierarchical groups of co-involved joints. To characterize these patterns, we developed sparse multilayer non-negative matrix factorization (NMF). Model selection by internal bi-cross-validation identified seven joint patterns at presentation, to which all 640 discovery patients were assigned: pelvic girdle (57 patients), fingers (25), wrists (114), toes (48), ankles (106), knees (283), and indistinct (7). Patterns were distinct from clinical subtypes (P < 0.001 by χ2 test) and reproducible through external data set validation on a 119-patient, prospectively collected independent validation cohort (reconstruction accuracy Q2 = 0.55 for patterns; 0.35 for groups). Some patients matched multiple patterns. To determine whether their disease outcomes differed, we further subdivided the 640 discovery patients into three subgroups by degree of localization-the percentage of their active joints aligning with their assigned pattern: localized (≥90%; 359 patients), partially localized (60%-90%; 124), or extended (<60%; 157). Localized patients more often maintained their baseline patterns (P < 0.05 for five groups by permutation test) than nonlocalized patients (P < 0.05 for three groups by permutation test) over a five-year follow-up period. We modelled time to zero joints in the discovery cohort using a multivariate Cox proportional hazards model considering joint pattern, degree of localization, and ILAR subtype. Despite receiving more intense treatment, 50% of nonlocalized patients had zero joints at one year compared to six months for localized patients. Overall, localized patients required less time to reach zero joints (partial: P = 0.0018 versus localized by log-rank test; extended: P = 0.0057). Potential limitations include the requirement for patients to be treatment naïve (except NSAIDs), which may skew the patient cohorts towards milder disease, and the validation cohort size precluded multivariate analyses of disease trajectories.
Multilayer NMF identified patterns of joint involvement that predicted disease trajectory in children with arthritis. Our hierarchical unsupervised approach identified a new clinical feature, degree of localization, which predicted outcomes in both cohorts. Detailed assessment of every joint is already part of every musculoskeletal exam for children with arthritis. Our study supports both the continued collection of detailed joint involvement and the inclusion of patterns and degrees of localization to stratify patients and inform treatment decisions. This will advance pediatric rheumatology from counting joints to realizing the potential of using data available from uncovering patterns of joint involvement.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Vitamin D and juvenile idiopathic arthritis Finch, Sarah L; Rosenberg, Alan M; Vatanparast, Hassan
Pediatric rheumatology online journal,
05/2018, Letnik:
16, Številka:
1
Journal Article
Recenzirano
Odprti dostop
Vitamin D has been implicated in the pathogenesis of autoimmune diseases. While the roles of vitamin D in other autoimmune diseases have been investigated, less is known about the role of vitamin D ...in chronic childhood arthritis.
This review summarizes and evaluates evidence relating to 25-hydroxyvitamin D (25(OH)D) and chronic childhood arthritis. A scoping literature review was conducted using Ovid Medline, Ovid Embase, Cumulative Index to Nursing and Allied Health Literature, Web of Science and Scopus. Further, we geo-mapped the results of the studies to identify the patterns of the association between vitamin D and chronic childhood arthritis across the globe. Of 38 studies reporting 25(OH)D concentrations in childhood chronic arthritis, 32 (84.2%) reported that a significant number of children had suboptimal (< 75 nmol/L) status.
The data indicate suboptimal vitamin D status in children with chronic arthritis. Further, the association between low vitamin D and increased arthritis activity follow a north-south geographical gradient.
Objective
Individuals with deficiency of adenosine deaminase 2 (DADA2), a recently recognized autosomal recessive disease, present with various systemic vascular and inflammatory manifestations, ...often with young age at disease onset or with early onset of recurrent strokes. Their clinical features and histologic findings overlap with those of childhood‐onset polyarteritis nodosa (PAN), a primary “idiopathic” systemic vasculitis. Despite similar clinical presentation, individuals with DADA2 may respond better to biologic therapy than to traditional immunosuppression. The aim of this study was to screen an international registry of children with systemic primary vasculitis for variants in ADA2.
Methods
The coding exons of ADA2 were sequenced in 60 children and adolescents with a diagnosis of PAN, cutaneous PAN, or unclassifiable vasculitis (UCV), any chronic vasculitis with onset at age 5 years or younger, or history of stroke. The functional consequences of the identified variants were assessed by ADA2 enzyme assay and immunoblotting.
Results
Nine children with DADA2 (5 with PAN, 3 with UCV, and 1 with antineutrophil cytoplasmic antibody–associated vasculitis) were identified. Among them, 1 patient had no rare variants in the coding region of ADA2 and 8 had biallelic, rare variants (minor allele frequency <0.01) with a known association with DADA2 (p.Gly47Arg and p.Gly47Ala) or a novel association (p.Arg9Trp, p.Leu351Gln, and p.Ala357Thr). The clinical phenotype varied widely.
Conclusion
These findings support previous observations indicating that DADA2 has extensive genotypic and phenotypic variability. Thus, screening ADA2 among children with vasculitic rash, UCV, PAN, or unexplained, early‐onset central nervous system disease with systemic inflammation may enable an earlier diagnosis of DADA2.
Abstract
Objective
To assess changes in juvenile idiopathic arthritis (JIA) treatments and outcomes in Canada, comparing 2005–2010 and 2017–2021 inception cohorts.
Methods
Patients enrolled within ...three months of diagnosis in the Research in Arthritis in Canadian Children Emphasizing Outcomes (ReACCh-Out) and the Canadian Alliance of Pediatric Rheumatology Investigators Registry (CAPRI) cohorts were included. Cumulative incidences of drug starts and outcome attainment within 70 weeks of diagnosis were compared with Kaplan–Meier survival analysis and multivariable Cox regression.
Results
The 2005–2010 and 2017–2021 cohorts included 1128 and 721 patients, respectively. JIA category distribution and baseline clinical juvenile idiopathic arthritis disease activity (cJADAS10) scores at enrolment were comparable. By 70 weeks, 6% of patients (95% CI 5, 7) in the 2005–2010 and 26% (23, 30) in the 2017–2021 cohort had started a biologic DMARD (bDMARD), and 43% (40, 47) and 60% (56, 64) had started a conventional DMARD (cDMARD), respectively. Outcome attainment was 64% (61, 67) and 83% (80, 86) for inactive disease (Wallace criteria), 69% (66, 72) and 84% (81, 87) for minimally active disease (cJADAS10 criteria), 57% (54, 61) and 63% (59, 68) for pain control (<1/10), and 52% (47, 56) and 54% (48, 60) for good health-related quality of life (≥9/10).
Conclusion
Although baseline disease characteristics were comparable in the 2005–2010 and 2017–2021 cohorts, cDMARD and bDMARD use increased with a concurrent increase in minimally active and inactive disease. Improvements in parent and patient-reported outcomes were smaller than improvements in disease activity.
PDF
