Atopic status and level of bronchial responsiveness in parents of children with acute bronchiolitis.

To examine whether children with a genetic predisposition to asthma are more likely to be afflicted with bronchiolitis, we studied 122 parents of infants who were hospitalized with the diagnosis of acute bronchiolitis (index group) and 120 parents of children who had never suffered from this disease (control group). The parents underwent bronchial challenge testing with methacholine and skin prick testing with common airborne allergens, and gave blood specimens for measurement of serum total IgE. There was no difference in atopic status, as assessed by the prevalence of atopy (at least one positive response to the allergens tested) or by serum total IgE levels, between index and control parents. The prevalence of bronchial hyperresponsiveness (BHR) (concentration of methacholine causing a 20% reduction in forced expiratory volume in 1 sec [PC20] < 18 mg/mL) was higher in index parents than in control parents (17.2% vs. 7.5%, p = 0.02). Bronchial responsiveness (BR) index was significantly higher in index parents than in control parents (1.135 +/- 0.088 vs. 1.104 +/- 0.071, p < 0.01). Parents of children who were hospitalized with acute bronchiolitis showed a higher level of BR, but not atopy. This suggests that in terms of BHR, there may be a genetic predisposition to the development of bronchiolitis.     

Polymerase chain reaction (PCR) for human herpesvirus 8 and heteroduplex PCR for clonality assessment in angiolymphoid hyperplasia with eosinophilia and Kimura's disease

BACKGROUND: Recently, human herpesvirus 8 (HHV-8) has been isolated from almost all cases of Kaposi's sarcoma. It has not been found in most cutaneous hemangioproliferative disorders other than Kaposi's sarcoma. Benign vascular lesions including Kimura's disease were not found to contain the HHV-8 DNA sequence. However, there has been contradictory data concerning the presence of HHV-8 in angiolymphoid hyperplasia with eosinophilia (ALHE). Clonality studies in ALHE and Kimura's disease were rare. METHODS: We performed polymerase chain reaction (PCR)-based analysis to determine whether HHV-8 is present and heteroduplex analysis of rearranged T-cell receptor (TCR) gene for clonality assessment in paraffin-embedded skin biopsy samples of 7 ALHE and 2 Kimura's disease, taken from immunocompetent patients. RESULTS: HHV-8 could not be identified in all the cases of ALHE and Kimura's disease. Although 2 cases (2/7) of ALHE and 2 cases (2/2) of Kimura's disease showed positive result for PCR analysis of TCR, all the cases were negative for heteroduplex-PCR. CONCLUSIONS: We suggest that HHV-8 may not involve in a pathogenetic role in ALHE and Kimura's disease and the failure to demonstrate clonality may be consistent with the reactive nature of these diseases and lack of malignant transformation. In addition, heteroduplex-PCR can be applied to confirm doubtful cases of lymphoma in that heteroduplex-PCR is more specific than PCR as seen in our study.     

Membrane of hybrid chitosan–silica xerogel for guided bone regeneration

Chitosan–silica xerogel hybrid membranes were fabricated using a sol–gel process and their potential applications in guided bone regeneration (GBR) were investigated in terms of their in vitro cellular activity and in vivo bone regeneration ability. TEM observation revealed that the silica xerogel was dispersed in the chitosan matrix on the nanoscale. The hybrid membrane showed superior mechanical properties to chitosan in the wet state and the rapid induction of calcium phosphate minerals in simulated body fluid, reflecting its excellent in vitro bone bioactivity. Osteoblastic cells were observed to adhere well and grow actively on the hybrid membrane to a level higher than that observed on the chitosan membrane. The alkaline phosphatase activity of the cells was also much higher on the hybrid than on the chitosan membrane. The in vivo study in a rat calvarial model demonstrated significantly enhanced bone regeneration using the hybrid membrane compared to that observed using the pure chitosan one. Histomorphometric analysis performed 3 weeks after implantation revealed a fully closed defect in the hybrid membrane, whereas there was only 57% defect closure in the chitosan membrane.