The remarkable deformability of red blood cells (RBCs) depends on the viscoelasticity of the plasma membrane and cell contents and the surface area to volume (SA:V) ratio; however, it remains unclear which of these factors is the key determinant for passage through small capillaries. We used a microfluidic device to examine the traversal of normal, stiffened, swollen, parasitised and immature RBCs. We show that dramatic stiffening of RBCs had no measurable effect on their ability to traverse small channels. By contrast, a moderate decrease in the SA:V ratio had a marked effect on the equivalent cylinder diameter that is traversable by RBCs of similar stiffness. We developed a finite element model that provides a coherent rationale for the experimental observations, based on the nonlinear mechanical behaviour of the RBC membrane skeleton. We conclude that the SA:V ratio should be given more prominence in studies of RBC pathologies.
To evaluate the performance of the Birmingham Vasculitis Activity Score (BVAS) v3 and the Disease Extent Index (DEI) for the assessment of disease activity in 4 primary childhood (c-) systemic vasculitides.Patients fulfilling the EULAR/PRINTO/PRES (Ankara) c-vasculitis classification criteria for Henoch-Schönlein purpura (HSP), childhood (c) polyarteritis nodosa (c-PAN), c-Wegener's granulomatosis (c-WG) and c-Takayasu arteritis (c-TA) with disease duration at the time of diagnosis ≤3 months were extracted from the PRINTO database. The performance of the BVAS and DEI were examined by assessing convergent validity, the pattern of disease involvement, and responsiveness. We also evaluated alternative unweighted scoring methods for both tools.The analysis set included 796 patients with 669 HSP, 80 c-PAN, 25 c-WG and 22 c-TA. The median age at diagnosis was 6.9 years (6.6-12) and median delay in making the diagnosis from the onset of signs/symptoms was 0.01 (0.003-0.027) years. A strong correlation was found between the BVAS and DEI (rs=0.78) while correlation with the physician global assessment was moderate (rs=0.48) with BVAS and poor with DEI (rs=0.25). Both the BVAS and DEI sub-scores and total scores were able to descrive the disease involvement in the 4 childhood vasculitides. Responsiveness was large (>1.5) for both tools. The performance characteristics of the BVAS and DEI with the unweighted methods were comparable.This study demonstrates that both the BVAS and DEI are valid tools for the assessment of the level of disease activity in a large cohort of childhood acute and chronic vasculitides.
Toumeyella parvicornis (Cockerell), the Pine tortoise scale, is reported for the first time from Europe. Pre-imaginal instars and adults were observed starting from the fall of 2014 in several municipalities of Campania (Italy). Since the species is recorded as a harmful pest of several pine species in North America and the Caribbean, the presence of this alien insect in Europe is alarming and represents a possible major threat for native pine species and related economic activities.
Objectives To assess risk factors for a first thrombotic event in confirmed antiphospholipid (aPL) antibody carriers and to evaluate the efficacy of prophylactic treatments. Methods Inclusion criteria were age 18–65 years, no history of thrombosis and two consecutive positive aPL results. Demographic, laboratory and clinical parameters were collected at enrolment, once a year during the follow-up and at the time of the thrombotic event, whenever that occurred. Results 258 subjects were prospectively observed between October 2004 and October 2008. The mean±SD follow-up was 35.0±11.9 months (range 1–48). A first thrombotic event (9 venous, 4 arterial and 1 transient ischaemic attack) occurred in 14 subjects (5.4%, annual incidence rate 1.86%). Hypertension and lupus anticoagulant (LA) were significantly predictive of thrombosis (both at p<0.05) and thromboprophylaxis was significantly protective during high-risk periods (p<0.05) according to univariate analysis. Hypertension and LA were identified by multivariate logistic regression analysis as independent risk factors for thrombosis (HR 3.8, 95% CI 1.3 to 11.1, p<0.05, and HR 3.9, 95% CI 1.1 to 14, p<0.05, respectively). Conclusions Hypertension and LA are independent risk factors for thrombosis in aPL carriers. Thromboprophylaxis in these subjects should probably be limited to high-risk situations.
To investigate the clinical and laboratory patterns of HCV-unrelated cryoglobulinaemic vasculitis (CV), and the factors influencing its outcome.Prospective study of all anti-HCV and HCV-RNA negative patients with CV who have been observed since January 2004 in 17 centres participating in the Italian Group for the Study of Cryoglobulinaemias (GISC).175 enrolled were followed up for 677 person-years. The associated conditions were primary Sjögren's syndrome (21.1%), SLE (10.9%), other autoimmune disorders (10.9%), lymphoproliferative diseases (6.8%), solid tumours (2.3%) and HBsAg positivity (8.6%), whereas 69 patients (39.4%) had essential CV. There were significant differences in age (p<0.001), gender (p=0.002), the presence of purpura (p=0.005), arthralgia (p=0.009), liver abnormalities (p<0.001), sicca syndrome (p<0.001), lymphadenopathy (p=0.003), splenomegaly (p=0.002), and rheumatoid factor titres (p<0.001) among these groups. Type II mixed cryoglobulins were present in 96 cases (54.9%) and were independently associated with purpura and fatigue (odds ratio [OR]4.3; 95% confidence interval [CI] 1.8-10.2; p=0.001; and OR2.8; 95%CI 1.3-6.3; p=0.012). Thirty-one patients died during follow-up, a mortality rate of 46/1000 person-years. Older age (for each additional year, adjusted hazard ratio [aHR] 1.13; 95%CI 1.06-1.20; p<0.001), male gender (aHR 3.45; 95%CI 1.27-9.40; p=0.015), type II MCG (aHR 3.31; 95%CI 0.09-1.38; p=0.047) and HBsAg positivity (aHR 7.84; 95%CI 1.20-36.04; p=0.008) were independently associated with greater mortality.HCV-unrelated CV is a multifaceted and often disabling disorder. The associated conditions influence its clinical severity, giving rise to significantly different clinical and laboratory profiles and outcomes.
