Type II and VI collagen in nasal and articular cartilage and the effect of IL-1α on the distribution of these collagens

The distribution of type II and VI collagen was immunocytochemically investigated in bovine articular and nasal cartilage. Cartilage explants were used either fresh or cultured for up to 4 weeks with or without interleukin 1α (IL-1α). Sections of the explants were incubated with antibodies for both types of collagen. Microscopic analyses revealed that type II collagen was preferentially localized in the interchondron matrix whereas type VI collagen was primarily found in the direct vicinity of the chondrocytes. Treatment of the sections with hyaluronidase greatly enhanced the signal for both types of collagen. Also in sections of explants cultured with IL-1α a higher level of labeling of the collagens was found. This was apparent without any pre-treatment with hyaluronidase. Under the influence of IL-1α the area positive for type VI collagen that surrounded the chondrocytes broadened. Although the two collagens in both types of cartilage were distributed similarly, a remarkable difference was the higher degree of staining of type VI collagen in articular cartilage. Concomitantly we noted that digestion of this type of cartilage hardly occurred in the presence of IL-1α whereas nasal cartilage was almost completely degraded within 18 days of culture. Since type VI collagen is known to be relatively resistant to proteolysis we speculate that the higher level of type VI collagen in articular cartilage is important in protecting cartilage from digestion

Trace elements as a component of oxidative stress in COPD

Objective: The purpose of this study was to assess the serum concentrations of those trace elements that act as a component of oxidative stress in COPD patients. Clinically stable COPD outpatients (n = 26) and healthy controls (n = 24) were studied.Methodology: Serum concentrations of copper (Cu) and zinc (Zn) were determined using a Varian Spectra AA220 flame atomic absorption spectrophotometer. Serum concentration of iron (Fe) was measured by the ferene assay, using a commercially available kit (IL Test(TM) Iron) with the ILAb(TM) 900 autoanalyser. The lipid peroxidation product malondialdehyde (MDA) in serum samples was measured spectrophotometrically in terms of TBARS (thiobarbituric acid reactive substances).Results: The serum MDA concentration in COPD patients was found to be similar to the control group (0.68 +/- 0.15 nmol/mL vs 0.62 +/- 0.13 nmol/mL, respectively; P = 0.163). The serum concentrations of the trace elements in both study groups were in the normal reference range. There was no difference in Fe concentration between COPD patients and the control group (0.81 +/- 0.38 mug/mL vs 0.92 +/- 0.41 mug/mL; P = 0.360). Copper concentrations were higher (1.06 +/- 0.26 mug/mL vs 0.92 +/- 0.19 mug/mL; P < 0.040); while zinc was lower in the COPD group compared to the controls (0.83 +/- 0.25 mug/mL us 1.03 +/- 0.23 mug/mL; P = 0.006). Serum Zn concentrations were lower in the severe COPD patients compared to mild-moderate COPD patients (P = 0.038).Conclusion: The results of this study indicate that there are alterations in serum concentrations of trace elements in COPD patients, suggesting that they may play a role in the pathophysiology of this disease by virtue of their role in oxidative stress. We recommend further studies on the role of trace elements in the pathophysiology of COPD, their association with markers of oxidant/antioxidant status and on the clinical significance of their deficiency

The rabbit as an animal model for post-natal vitreous matrix differentiation and degeneration

Purpose This study evaluates whether rabbits are a suitable animal model to study post-natal vitreous differentiation and degeneration. Methods Human and rabbit eyes of various ages were studied by complementary anatomical techniques, light microscopy, and transmission electron microscopy. Results The global vitreous matrix organization is similar in human and rabbit eyes, lamellae are an important aspect thereof and show striking morphological changes with increasing age. In humans, liquefaction is more conspicuous than in rabbits but changes in matrix histology consistent with liquefaction can also be observed in the latter. Conclusions Lamellar development is consistent with vitreous differentiation, while increasing liquefaction is consistent with matrix degeneration. At the anatomical and histological levels, human and rabbit vitreous matrices are sufficiently similar to make the rabbit a promising animal model for the study of the pathogenesis of vitreous matrix differentiation and degeneration in more detail