Rheumatoid plantar synovial cysts

[Clinical and laboratory characteristics of rheumatoid arthritis with positive antinuclear antibody]

OBJECTIVE

To analyse the clinical and laboratory characteristics of antinuclear antibody (ANA) positive rheumatoid arthritis (RA) patients.

METHODS

The clinical and laboratory data of 428 RA cases from Department of of Rheumatology and Immunology Peking University Third Hospital from Jan 2013 to Dec 2018 were collected and used to analyse characters between ANA positive group and ANA negative group. T test was used for the quantitative data in accordance with normal distribution. Wilcoxon rank sum test was used for the quantitative data of non normal distribution. The qualitative data were analyzed by chi square test. But while 1≤theoretical frequency < 5, chi square test of corrected four grid table was used. And Fisher exact probability method was used when theoretical frequency < 1.

RESULTS

The number of ANA positive group was 231 (54%). The female rate was obviously higher in ANA positive group (82.7% vs. 63.5%, χ²=20.355, P < 0.01). The rate of metatarsophalangeal joints (MTPJs) involvement was lower in ANA positive group (22.1%) than in ANA negative group (33.0) (χ²=6.414, P < 0.05). The incidence of secondary Sjögren's syndrome (sSS) was much higher in ANA positive group(19.5% vs. 4.1%, χ²=23.300, P < 0.01). The positivity of rheumatoid factor (RF), as well as the positivity of anti-cyclic citrullinated peptide(CCP) antibody was much higher in ANA positive group (77.1% vs. 53.8%, χ²=25.743, P < 0.01, 74.9% vs. 59.4%, χ²=11.694, P < 0.01, respectively). The levels of immunoglobulin G (IgG) and immunoglobulin M (IgM) of ANA positive group were higher [(15.1±5.1) g/L vs. (13.8±5.3) g/L, t=2.359, P < 0.05, 1.25 (0.92) g/L vs. 1.05 (0.65) g/L, Z=-3.449, P < 0.01, respectively]. But the levels of hemoglobin (Hb) and platelet (PLT) was lower in ANA positive group[(109.64±17.98) vs. (114.47±18.48) g/L, t=-2.734, P < 0.01; (266.4×10⁹±104.6×10⁹) vs. (295.9×10⁹±100.1×10⁹) /L, t=-2.970, P < 0.01, respectively].

CONCLUSION

The incidence of sSS was obviously higher in ANA positive group than in ANA negative group. Serum IgG of ANA positive group was higher, but Hb and PLT were lower.

Monte Carlo simulations of polyampholyte-polyelectrolyte complexes: effect of charge sequence and strength of electrostatic interactions

We present the results of Monte Carlo simulations of complexation between polyampholyte and polyelectrolyte chains. Polymers are modeled as bead-spring chains of charged Lennard-Jones particles each consisting of 32 monomers. Formation of a polyampholyte-polyelectrolyte complex is driven by polarization-induced attractive interactions. The complex is usually formed at the end of the polyelectrolyte with the polyampholyte chain elongated and aligned along the polyelectrolyte backbone. This complex structure between the polarized polyampholyte chain and the polyelectrolyte leads to maximization of the attractive and minimization of the repulsive electrostatic interactions. The size of a polyampholyte in a complex is usually larger than that of an isolated polyampholyte chain. We also observed that initially collapsed polyampholytes undergo a coil-globule transition by forming a complex. The structure of a polyampholyte-polyelectrolyte complex was analyzed by tail and loop distribution functions. We have found that the number of loops increases while their sizes decrease with the strength of the electrostatic interactions. Polyampholytes with random charge sequence form stronger complexes with polyelectrolytes than those with alternating charge sequence. Polyampholytes with long blocky sequences form a double helix with a polyelectrolyte at sufficiently large values of the Bjerrum length.

Giant synovial cysts

Giant synovial cysts (GSC) are large, well-defined cavities, containing synovial fluid and lined by a synovium-like membrane, which extend for a variable distance outside the joint cavity. We are reporting 15 cases of GSC of various joints. Rheumatoid arthritis is the most common disease process reported in association with GSC. We suggest that trauma may be a more important cause of GSC than has previously been described. Arthrography and ultrasonography are both helpful in diagnosing these large cysts, especially in the knee to aid in differentiating GSC from thrombophlebitis.

The formation of a stable complex between dissociated proteoglycan and hyaluronic acid in the absence of a link protein

A proteoglycan fraction prepared from bovine articular cartilage under dissociative conditions was shown to interact with three purified hyaluronic acid preparations to form stable complexes in the analytical ultracentrifuge. It is concluded from these experiments that, although link proteins are associated with hyaluronic acid and proteoglycans in complexes between these macromolecular constituents.