Prevalence of undiagnosed psoriatic arthritis among psoriasis patients: Systematic review and meta-analysis.

BACKGROUND: Skin psoriasis precedes the onset of psoriatic arthritis (PsA) in 84% of patients with psoriasis. Dermatologists have an important role to screen psoriasis patients for PsA. The efficiency of PsA screening remains unknown. OBJECTIVE: We sought to determine the point prevalence of undiagnosed PsA in patients with psoriasis using a systematic search of the literature and meta-analysis. METHODS: PubMed, Cochrane, and Embase database searches yielded 394 studies for review. No study aimed to determine the prevalence of undiagnosed PsA in patients with psoriasis. We assumed that the prevalence of newly diagnosed PsA in patients with psoriasis at the time they seek medical care could be a sound estimate of this value. Seven epidemiological studies and 5 studies on PsA screening questionnaires allowed us to clearly identify patients with newly diagnosed PsA and were selected for review. RESULTS: The prevalence of undiagnosed PsA was 15.5% when all studies were considered and 10.1% when only epidemiological studies were considered. LIMITATIONS: Data were obtained from studies not designed to address the question at hand. Heterogeneity was high (I(2) = 96.86%), and therefore a random effects model was used. CONCLUSION: The high prevalence of undiagnosed PsA in patients with psoriasis adds to the recommendation that dermatologists need to screen all patients with psoriasis for PsA.

The mouse dorsal skinfold chamber as a model for the study of thrombolysis by intravital microscopy.

Although intravital microscopy models of thrombosis in mice have contributed to dissect the mechanisms of thrombus formation and stability, they have not been well adapted to study long-term evolution of occlusive thrombi. Here, we assessed the suitability of the dorsal skinfold chamber (DSC) for the study of thrombolysis and testing of thrombolytic agents by intravital microscopy. We show that induction of FeCl3-induced occlusive thrombosis is achievable in microvessels of DSCs, and that thrombi formed in DSCs can be visualised by intravital microscopy using brightfield transmitted light, or fluorescent staining of thrombus components such as fibrinogen, platelets, leukocytes, and von Willebrand factor. Direct application of control saline or recombinant tissue-plasminogen activator (rtPA) to FeCl3-produced thrombi in DSCs did not affect thrombus size or induce recanalisation. However, in the presence of hirudin, rtPA treatment caused a rapid dose-dependent lysis of occlusive thrombi, resulting in recanalisation within 1 hour after treatment. Skin haemorrhage originating from vessels located inside and outside the FeCl3-injured area was also observed in DSCs of rtPA-treated mice. We further show that rtPA-induced thrombolysis was enhanced in plasminogen activator inhibitor-1-deficient (PAI-1-/-) mice, and dropped considerably as the time between occlusion and treatment application increased. Together, our results show that by allowing visualization and measurement of thrombus lysis and potential bleeding complications of thrombolytic treatments, the DSC provides a model for studying endogenous fibrinolysis and for first-line screening of thrombolytic agents. Furthermore, using this system, we found that thrombin and clot aging impair the thrombolytic action of rtPA towards FeCl3-produced thrombi.