In vitro comparison of three different mesh constructions.

BACKGROUND: Material amount and pore size have been recently discussed as probable important determinants of biocompatibility of mesh implants used in hernia repair. This study aimed to find out whether other constructional parameters affect the extent of early foreign body reaction in vitro. MATERIALS AND METHODS: An NRK-49F (mixed culture of normal rat kidney cells) fibroblast culture was incubated in the presence of a 'light' microporous mesh (35 g/m(2), 0.25 mm thick), a 'heavy' polypropylene knitted mesh (95 g/m(2), 0.55 mm thick) and a polypropylene/polyglactin composite mesh (35 g/m(2), 0.5 mm thick). A mesh-free cell suspension was used as a control group. Fibroblasts' proliferation, invasion and apoptosis rates were measured by commercially available quantification tests. Levels of tumour necrosis factor-alpha, transforming growth factor-beta1, interleukin (IL)-1 beta, IL-6 and IL-10 secreted by the fibroblasts in the supernatant were dynamically measured in a time kinetics of 6-96 h. RESULTS: Invasion potential as well as proliferation and apoptosis rates of fibroblasts were enhanced by all meshes. The composite mesh stimulated the cell turnover with correspondingly increased levels of IL-6 and suppressed levels of transforming growth factor-beta1 significantly more than the two pure polypropylene meshes and the control group. CONCLUSION: Early biological response of fibroblasts as a major component of foreign body reaction was most affected by the filament construction of the mesh combining polypropylene with multifilament, partially absorbable polyglactin fibres. Material reduction did not weaken foreign body reaction. Confirming previous findings from animal experiments and clinical observations, the described in vitro model seems to be an appropriate primary tool for studying the biological tolerance towards meshes.

Short-term effect of solidified benzyl benzoate on mite-allergen concentrations in house dust.

The effect of solidified benzyl benzoate (bb) foam and powder on concentrations of the major allergens of Dermatophagoides pteronyssinus (Der p I) and D. farinae (Der f I) in dust samples from mattresses and carpets in 22 households was investigated in a randomized, double-blind, placebo-controlled trial. All houses had been demonstrated to have significant (greater than or equal to 2000 ng/gm of dust) mite-allergen concentrations on mattresses. Dust samples were collected from mattresses and carpets before treatment and on days 10, 30, and 60 after the first treatment. There was a second application on day 10. Der p I and Der f I were determined by a sandwich-type ELISA with monoclonal noncross-reacting antibodies to Der p I and polyclonal monospecific antibodies to Der f I. There was a significant reduction of mite allergens in mattresses and carpets within both bb-treated and control groups, but only the results on carpets of the bb-treated group were significantly different from results of the control group on days 30 and 60 (p less than 0.05).

High mite-allergen exposure increases the risk of sensitization in atopic children and young adults.

Concentrations of major allergens of Dermatophagoides pteronyssinus (Dpt) and D. farinae (Df), Der p I and Der f I, were determined in 183 dust samples of mattresses of 133 atopic and 50 nonatopic children by a sandwich-type ELISA. Atopic children and young adults living in houses with high levels of Der p I and Der f I (greater than or equal to 2000 ng/gm of dust) were found to have significantly higher serum IgE levels to Dpt and Df (p less than 0.0001) compared to patients with low mite-allergen exposure. Washed leukocytes of 55 atopic children and 14 control subjects were investigated for in vitro histamine release to serial dilutions of Der p I; 86% of highly exposed (greater than or equal to 10,000 ng/gm) children demonstrated positive histamine release in response to Der p I compared to 17% in the group with very low exposure (less than 400 ng/gm). There was a positive correlation between basophil sensitivity (rs = 0.6; p less than 0.0001) and reactivity (rs = 0.54; p less than 0.0001) to Der p I and mite-allergen exposure. The relative risk for sensitization in the highly exposed group versus the group with very low exposure was sevenfold to 32-fold increased. We conclude that high concentrations of mite allergen (greater than or equal to 2000 ng/gm) increase the risk of specific sensitization in atopic children and young adults and thus may facilitate allergic airway disease.