This paper describes a method to preserve functioning islets of Langerhans from mice in Millipore® chamber during eight days of implantation in subcutaneous tissue of normal mice. In vitro it might be difficult to imitate the real conditions which influence the islets of Langerhans (Andersson 1973). Therefore we investigated the possibility of preserving isolated

In cases of gout with a low synovial fluid (SF) leukocyte count and atypical clinical presentation, such as in intercritical periods, the load of monosodium urate (MSU) crystals is frequently low, and thus, methods to improve the crystal detection may be beneficial. We compared the MSU crystal detection rates between cytospin slides and common smear preparations in low-cellular (<2,000/μl) SF samples of patients with gout. We determined the number of MSU crystals/15 high power fields (HPF) at × 1,000 magnification by polarised microscopy in cytospin preparations and smears in SF samples of 17 patients with MSU-crystal-proven gout and compared the two methods statistically. All of the cytospin slides (100 %) contained MSU crystals and showed a median number of 124 crystals/15 HPF (range 2-3,915), whereas 5 of the 17 smears (29 %) were MSU-crystal-negative, with a median count of 2 crystals/15 HPF (range 0-430/HPF). The difference was statistically highly significant (p < 0.0001). In conclusion, we have shown that the cytospin technique is superior to smears in the detection of MSU crystals in SF with a low SF leukocyte count. In light of our observations, we recommend the use of cytocentrifuges for routine crystal analysis in such cases.

In synovial fluids (SF) with low leukocyte or/and crystal counts, important features may be missed, if exclusively smears are examined by polarized microscopy. That may be overcome by cytocentrifuges, which use low-speed centrifugal force to concentrate cells onto a glass slide and thus enhance the number of cells per high power field (HPF). We compared the calcium pyrophosphate (CPP) crystal counts in cytospin preparations with those in common smears of SF. The number of CPP crystals was counted in 50 SF samples by polarized microscopy, and statistical comparisons of the mean values of the cytospin and smear preparations were performed using the Wilcoxon test. The reproducibility within the slides of the cytocentrifuge and smear samples was determined by Spearman's rank correlation. The crystal counts were significantly higher in the cytospin than in the smear preparations (median 96/10 HPF vs. 2.5/10 HPF, p < 0.0001). The correlation in the crystal count between the slides 1 and 2 was significantly higher within the cytocentrifuge than in the smear group (0.97 vs. 0.73, p = 0.0004). CPP-negative cytospin preparations in initially smear-positive slides were not observed. We confirmed that the cytospin technique significantly enhances the number of examinable crystals per HPF, compared to common smears.

No abstract

There are only a few studies dealing with the detection and clinical impact of calcium pyrophosphate (CPPD) crystals in patients with rheumatoid arthritis (RA) published to date. In particular, data determined by the cytospin technique, which is an effective tool to enhance the crystal detection rate, are lacking. The objectives of this study were to determine the prevalence of CPPD crystals in the synovial fluid (SF) of patients with RA and to investigate whether the detection of CPPD crystals is correlated with demographic, clinical and serological features. We examined 113 consecutive SF samples of patients with RA, obtained from therapeutic arthrocentesis of knee joints. After cytocentrifugation, the sediments were examined by polarized microscopy for the occurrence of CPPD crystals. Demographic, clinical and serological data, acquired from the medical records, were compared between crystal-positive and crystal-negative subjects. CPPD crystals were observed in 20 of the 113 cases, representing 17.7%. CPPD-positive and CPPD-negative subjects did not differ significantly in sex, duration of disease, Steinbrocker radiologic stage, disease activity score 28, as well as serum rheumatoid factor and anti-CCP positivity. Patients positively tested for CPPD crystals had a significantly higher age than CPPD-negative patients (p < 0.0001). An age-independent association of long-time treatment with diuretics and CPPD crystal formation was not found. In conclusion, demographic, clinical and serological characteristics of patients with RA were not associated with the occurrence of CPPD crystals. Age was the only significant influencing factor on CPPD crystal formation in patients with RA.