Decrease of inorganic blood sulfate following treatment with selected antirheumatic drugs: potential consequence for articular cartilage

The elimination kinetics of inorganic blood sulfate in mice was followed for four hours after a single, oral administration of an antirheumatic drug. Sodium salicylate, aspirin, diflunisal and benorylate, all in a dose of 1.25 mmol/kg, reduced the sulfate level to the less than half that of control. This phenomenon was also demonstrated by phenylbutazone, oxyphenbutazone (both 1 mmol/kg), chloroquine diphosphate (0.6 mmol/kg) and tiaprofenic acid (0.02-0.35 mmol/kg). Niflumic acid (1.08 mmol/kg), piroxicam (0.03 mmol/kg), indomethacin (6.10(-3) mmol/kg), diclofenac (5.10(-3) mmol/kg), ketoprofen (0.2 mmol/kg), naproxen (0.08 mmol/kg) and ibuprofen (0.24 mmol/kg) possessed no sulfate lowering properties. The potential relevance of the use of sulfate lowering drugs for articular cartilage integrity is discussed in the light of what is already known about this subject.     

The effect of low sulfate concentrations on the glycosaminoglycan synthesis in anatomically intact articular cartilage of the mouse

We have studied the effect of environmental sulfate concentration on the glycosaminoglycan synthesis of anatomically intact patellar cartilage of the mouse in vitro. Incubation of mouse patellae in medium with sulfate concentrations below 0.5 mM resulted in a diminished incorporation of sulfate but in unaltered incorporation of glucosamine. This suggested the synthesis of undersulfated glycosaminoglycans under these conditions. We characterized glycosaminoglycans synthesized at three different sulfate concentrations: a sulfate concentration physiological for the mouse (1.0 mM), a sulfate concentration in the range where sulfate incorporation was strongly diminished (0.1 mM), and an extremely low sulfate concentration (10 nM). Analysis of glycosaminoglycan disaccharides and DEAE anion chromatography of the glycosaminoglycans could not confirm the synthesis of undersulfated glycosaminoglycans at 0.1 mM. The chromatogram of glycosaminoglycans synthesized in medium containing 10 nM showed the presence of a very low sulfated glycosaminoglycan pool not observed at higher medium sulfate concentrations. Intermediately sulfated glycosaminoglycans were also synthesized during incubation with 10 nM sulfate. So, our data indicate that only very low sulfate concentrations in the medium lead to the synthesis of undersulfated glycosaminoglycans and that the sulfation mechanism of murine patellar cartilage chondrocytes does not seem to fit completely in an "all-or-nothing" pattern.     

Specific immunotherapy prevents increased levels of allergen-specific IL-4- and IL-13-producing cells during pollen season

BACKGROUND: Specific allergen immunotherapy (SIT) is effective for treatment of IgE-mediated diseases: however, the mechanisms of action still remain unclear. Earlier, we showed that IL-4 and IL-13 are produced in response to specific allergens. The aim of this study was to investigate whether these cytokine responses were affected by allergen SIT, and, furthermore, to evaluate the effect of SIT on allergen-specific IgE and IgG4 levels. METHODS: Blood samples from pollen-sensitized individuals were collected before the pollen season (before treatment) and during the pollen season (after SIT or placebo treatment). Peripheral blood mononuclear cells were activated in vitro with allergens and the numbers of IL-4-, IL-13-, IL-10-, and IFN-gamma-producing cells were determined by ELISPOT. Serum levels of allergen-specific IgE and IgG4 were measured by RAST and ELISA, respectively. RESULTS: The numbers of IL-4- and IL-13-producing cells were shown to be increased in the placebo group during the pollen season, an increment which was absent in patients receiving allergen SIT. We found an increase in allergen-specific IgG4 in the SIT-treated individuals, but not in the placebo group. Both groups displayed elevated specific IgE levels during the pollen season. CONCLUSIONS: Taken together, our data show a downregulation of IL-4- and IL-13-producing cells in peripheral blood after SIT, suggesting induction of nonresponsiveness/tolerance or a redistribution of these cells. Furthermore, we demonstrate that SIT acts on antibody production by increasing the specific IgG4 levels.     

Somatization in frequent attenders of general practice

The DSM-III-(R) definition of somatization disorder is too restrictive for use in general practice. A more comprehensive definition, the somatic symptom index (SSI) has shown good validity in open populations. However, a definition has to differentiate validlywithin a population of frequent attenders to be a useful diagnostic instrument in general practice. We studied a threshold of five complaints (nearly identical to the SSI) in 80 Dutch general practice patients. Patients were selected on age (20–44 years), history of back, neck or abdominal complaints, and on frequency of consultation—at least 12 consultations in the previous 3 years, corrected for consultations with compelling somatic reason for encounter. Prevalence of somatization in this group was 45%. Women had a 2 times higher risk of somatization. A relation with age was not found. Somatization was related to depressive complaints (relative risk 2.5) and probably also to anxiety. Somatizing patients consulted their general practitioner more often and had more health problems (especially psychic problems) than non-somatizers. These results support the validity of this definition. The distinction between our definition of somatization and somatization defined as a symptom of psychiatric (e.g. depressive or anxiety) disorder is emphasized.     

Effects of methotrexate on glycosaminoglycan production by scleroderma fibroblasts in culture.

OBJECTIVE--To determine the effects of increasing concentrations of methotrexate on the proliferation and glycosaminoglycan (GAG) synthesis of cultured dermal fibroblasts from patients with scleroderma. METHODS--Cultured dermal fibroblasts from nine patients with scleroderma and nine normal volunteers were grown for 72 hours in media containing various concentrations of methotrexate. The GAG synthesis in each cell was measured after incubating the fibroblasts with [3H]glucosamine and [35S]sulphate. RESULTS--A negative correlation was found between the concentration of methotrexate and numbers of fibroblasts from patients with scleroderma and normal controls. A positive correlation was found between GAG synthesis in each cell, as measured by [3H]glucosamine and [35S]sulphate incorporation, and increasing methotrexate concentrations in fibroblasts from patients with scleroderma and normal controls. CONCLUSIONS--These data indicate increased GAG synthesis in scleroderma and normal fibroblasts with increasing concentrations of methotrexate. Therefore the reported beneficial effect of methotrexate on skin fibrosis in scleroderma is most probably not the result of direct inhibition of GAG synthesis by fibroblasts.     

Analysis of the cell infiltrate and expression of proinflammatory cytokines and matrix metalloproteinases in arthroscopic synovial biopsies: comparison with synovial samples from patients with end stage,destructive rheumatoid arthritis

BACKGROUND: Synovial tissue (ST) from end stage destructive rheumatoid arthritis (RA) and arthroscopic biopsies obtained during active inflammation might exhibit different characteristics. OBJECTIVE: To define the cell infiltrate and the expression of proinflammatory cytokines, angiogenic factors, and matrix metalloproteinases (MMPs) in ST selected at arthroscopy compared with that from end stage RA. METHODS: Synovial biopsy specimens were obtained from the actively inflamed knee joints of 13 patients with chronic RA by arthroscopy and compared with ST from 10 patients with end stage, destructive RA. Immunohistological analysis was performed to detect T cells, plasma cells, macrophages, fibroblast-like synoviocytes (FLS), and the expression of interleukin (IL)1beta, IL6, tumour necrosis factor alpha (TNFalpha), MMP-1, MMP-3, MMP-13, TIMP-1, and VEGF. RESULTS: The expression of CD68+ macrophages was significantly higher in ST selected at arthroscopy than in samples obtained at surgery, both in the intimal lining layer and in the synovial sublining. The expression of CD3+ T cells also tended to be higher in arthroscopic samples. The expression of TNFalpha, IL6, MMP-1, MMP-3, MMP-13, TIMP-1, and VEGF was on average higher in ST obtained at arthroscopy. In contrast, the expression of IL1beta was on average higher in surgical samples. CONCLUSION: Active arthritis activity is associated with increased cell infiltration, expression of proinflammatory cytokines, MMPs, and angiogenic growth factors in synovial biopsy samples selected at arthroscopy. Increased expression of IL1beta in the synovium of patients with destructive RA requiring joint replacement may well reflect the important role of IL1beta in cartilage and bone destruction.     

Reduction of intra- and interlaboratory variation in CD34+ stem cell enumeration using stable test material, standard protocols and targeted training. DK34 Task Force of the European Working Group of Clinical Cell Analysis (EWGCCA)

The European Working Group on Clinical Cell Analysis (EWGCCA) has, in preparation for a multicentre peripheral blood stem cell clinical trial, developed a single-platform flow cytometric protocol for the enumeration of CD34+ stem cells. Using this protocol, stabilized blood and targeted training, the EWGCCA have attempted to standardize CD34+ stem cell enumeration across 24 clinical sites. Results were directly compared with participants in the UK National External Quality Assessment Scheme (NEQAS) for CD34+ Stem Cell Quantification that analysed the same specimens using non-standardized methods. Two bead-counting systems, Flow-Count and TruCount, were also evaluated by the EWGCCA participants during trials 2 and 3. Using Flow-Count, the intralaboratory coefficient of variation (CV) was 相似文献