Disinfection and sterilization of reusable devices]

Official of quality assurance requirements for the disinfection and sterilization of reusable medical devices in health care facilities has been reminded recently. These requirements concern good manufacturing practices, essential to avoid adverse events. Identification of non critical and invasive devices, protocols for pre-disinfection, cleaning, high level disinfection and sterilization for thermosensitive materials must be evaluated. Monitoring and process control of these operations are defined by French regulations and European standards, and every health professional has to become aware of these limits.     

Development of a microassay for estradiol receptors

The calculation of equilibrium binding constants for a specific receptor-hormone interaction requires the exact determination of the unbound ligand concentration and the specifically bound concentration at equilibrium. These determinations usually require corrections for the contribution of non-specific binding. We introduce several parameters allowing equilibrium concentrations to be calculated from experimental concentration values; these parameters can be measured for the particular receptor assay procedure used. These parameters are used in a microassay of estradiol-receptor complex by selective retention on DE-81 cellulose paper.     

Deletion of the central proline-rich repeat domain results in altered antigenicity and lack of surface expression of the Streptococcus mutans P1 adhesin molecule

Members of the family of surface adhesins of oral streptococci, including P1 of Streptococcus mutans, contain two highly conserved repeat domains, one rich in alanine (A region) and the other rich in proline (P region). To assess the contribution of the P region to the biological properties of P1, an internal deletion in spaP was engineered. In addition, the P region was subcloned and expressed as a fusion partner with the maltose binding protein of Escherichia coli and liberated by digestion with factor Xa. Results of Western blot experiments in which recombinant polypeptides were probed with a panel of 11 monoclonal antibodies indicated that the P region is a necessary component of conformational epitopes within the central portion of P1. Antibodies reactive with the P region were detected in a polyclonal rabbit antiserum generated against whole S. mutans cells but not in two rabbit antisera generated against purified P1 (Mr approximately 185,000), suggesting that this domain is immunogenic on the surface of intact bacteria but not as part of a soluble full-length molecule. Finally, transformation of a spaP-negative mutant with a shuttle vector containing an internally deleted spaP lacking P-region DNA resulted in a complete absence of surface-localized P1 and substantially less P1 in sonicated cells compared to the case for the mutant complemented with the full-length gene. These results suggest that the P region is an integral component contributing to the conformation of the central region of P1 and indicate that its presence is necessary for surface expression of the molecule on S. mutans.     

5-hydroxytryptamine1A receptor-mediated effects on adenylate cyclase and nitric oxide synthase activities in rat ventral prostate

AIM: To investigate the patterns of expression of transforming growth factor alpha (TGF-alpha) and epidermal growth factor receptor (EGFR) in squamous metaplasia and squamous cell carcinomas of the urinary bladder with and without schistosomiasis. METHODS: Immunohistochemical study of the expression of TGF-alpha and EGFR in squamous metaplasias (n = 12) and various grades of squamous cell carcinomas (n = 21) of the bladder with and without schistosomiasis. RESULTS: Focal cytoplasmic and membranous positivity for EGFR and TGF-alpha was seen in all cases of squamous metaplasia. The markers were diffusely coexpressed in a concordant pattern in areas of hyperplastic keratinising squamous metaplasia. A similar pattern of positivity was seen in verrucous carcinomas (n = 2) and well differentiated squamous carcinomas (n = 6). Progressive loss of differentiation was associated with increasing loss of EGFR staining while TGF-alpha staining was retained. Squamous cell carcinoma in situ (n = 2) showed focal positivity for TGF-alpha and EGFR. There were no differences in staining patterns between cases with and without schistosomiasis. CONCLUSIONS: The coexpression of TGF-alpha and EGFR by well differentiated squamous cell carcinomas and hyperplastic keratinising squamous metaplasia is consistent with the active regulatory role exerted by this autocrine loop. There is regional absence of expression of EGFR but not of TGF-alpha in squamous cell carcinomas of lesser differentiation, suggesting heterogeneity of such control in these tumours. The focal expression of the two markers in squamous cell carcinomas in situ indicates a possible second pathway of oncogenesis for less differentiated tumours. These observations may have important implications for the effectiveness of putative growth factor based treatments.     

Ocular chrysiasis correlated with gold concentrations in the crystalline lens during chrysotherapy

The eyes of 11 patients with rheumatoid arthritis (RA) who received extended chrysotherapy (mean cumulative dose greater than 7 grams during a mean 6-year period) were examined biomicroscopically. Minute reddish-purple particles were seen in the cornea (corneal chrysiasis) in 5 and in the lens (lens chrysiasis) in 4 patients. Particulate deposits were absent in 11 other RA patients who had not received gold treatment. Seven crystalline lenses from 5 gold-treated patients were removed surgically because of incidental cataract formation and analyzed for gold content using neutron activation analysis. Although the mean lens gold concentration was higher in these patients than in non-gold-treated controls without RA (0.0073 microgram/grams versus 0.001 microgram/grams), the absolute gold level was markedly lower than that found in 25 diverse tissue analyzed previously. This finding is compatible with the absence of clinical gold-related lens disease or visual impairment.