Increased risk of tuberculosis in health care workers: a retrospective survey at a teaching hospital in Istanbul,Turkey

Background  

Tuberculosis (TB) is an established occupational disease affecting health care workers (HCWs). Determining the risk of TB among HCWs is important to enable authorites to take preventative measures in health care facilities and protect HCWs. This study was designed to assess the incidence of TB in a teaching hospital in Istanbul, Turkey. This study is retrospective study of health records of HCWs in our hospital from 1991 to 2000.     

Preparation of a sialic acid-binding protein from Streptococcus mitis KS32AR.

A recent report has identified a lectin on the surfaces of several strains of Streptococcus mitis and Streptococcus sanguis with specificity for an N-acetylneuraminic acid alpha 2,3-galactose-beta 1,3-N-acetylgalactosamine sequence (P.A. Murray, M.J. Levine, L.A. Tabak, and M.S. Reddy, Biochem. Biophys. Res. Commun. 106:390-396, 1982). In the present study, purification and characterization of this sialic acid-binding protein (SABP) was begun. A clinical isolate of S. mitis was grown to mid stationary phase in synthetic FMC medium and then extracted with lithium 3,5-diiodosalicylate. Lyophilized extract was subjected to gel filtration on a Sephadex G-200 column, giving four protein peaks (A to D). Peak B, shown by hemagglutination assay to contain SABP, was next subjected to affinity chromatography on a Sepharose-4B matrix coupled to fetuin glycopeptides. After an extensive washing, peak B materials bound to the affinity matrix were eluted with buffered N-acetylneuraminic acid. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis with 2-mercaptoethanol on 7.5% gels of affinity-purified materials revealed components of 96, 70, and 65 kilodaltons (kDa). Without reducing agent, only the 65-kDa band and materials which did not penetrate the gel were visualized, suggesting that the 96- and 70-kDa components were disulfide linked. The chemical cross-linking agent, disuccinimidyl suberate, was used to demonstrate specific interactions between the SABP preparation and [14C]fetuin glycopeptides. After cross-linking, sodium dodecyl sulfate-polyacrylamide gel electrophoresis and fluorography revealed the 96- and 70-kDa components, indicating that the SABP is at least bivalent. These findings support our previous suggestion that human salivary glycoproteins facilitate clearance of selected oral streptococci via specific interactions between sialic acid-containing oligosaccharides and a carbohydrate-binding protein on the bacterial cell surface.     

A philosophy underlying excellence in teaching

This article discusses nursing education and changing paradigms of knowledge, emphasizing critical thinking, nursing praxis, and the place of the educator as a role model who provides knowledge, facilitates critical thinking, and teaches students how to cope with the knowledge. It interprets the connection between knowledge and power as a potential source of injustice and inequality in the student–teacher relationship; and tries to solve this problematic issue by annulling the differences in power. Examples from clinical areas are presented to illustrate differential power the educator‐teacher‐researcher has in different clinical areas.     

Risk of tuberculous infection among house staff in an urban teaching hospital

Physicians in training in our medical center were found to have a higher risk of tuberculous infection than other hospital employees. Their annual tuberculin conversion rate was 3.96%; in two of the 15 recent converters, active disease developed. There is a significant linear relationship between the acquisition of tuberculous infection and the duration of training in an urban teaching hospital. Their compliance rate to annual tuberculin testing and chemoprophylaxis is less than 50%.     

Metabolism and pharmacokinetics of a novel Src kinase inhibitor TG100435 ([7-(2,6-dichloro-phenyl)-5-methyl-benzo[1,2,4]triazin-3-yl]-[4-(2-pyrrolidin-1-yl-ethoxy)-phenyl]-amine) and its active N-oxide metabolite TG100855 ([7-(2,6-dichloro-phenyl)-5-methylbenzo[1,2,4]triazin-3-yl]-{4-[2-(1-oxy-pyrrolidin-1-yl)-ethoxy]-phenyl}-amine).

TG100435 ([7-(2,6-dichloro-phenyl)-5-methyl-benzo[1,2,4]triazin-3-yl]-[4-(2-pyrrolidin-1-yl-ethoxy)-phenyl]-amine) is a novel multitargeted, orally active protein tyrosine kinase inhibitor. The inhibition constants (K(i)) of TG100435 against Src, Lyn, Abl, Yes, Lck, and EphB4 range from 13 to 64 nM. TG100435 has systemic clearance values of 20.1, 12.7, and 14.5 ml/min/kg and oral bioavailability of 74%, 23%, and 11% in mouse, rat, and dog, respectively. Four oxidation metabolites of TG100435 have been found in human, dog, and rat in vitro and in vivo. The ethylpyrrolidine N-oxide of TG100435 is the predominant metabolite (TG100855; [7-(2,6-dichloro-phenyl)-5-methyl-benzo[1,2,4]triazin-3-yl]-{4-[2-(1-oxy-pyrrolidin-1-yl)-ethoxy]-phenyl}-amine) in human, dog, and rat. TG100855 is 2 to 9 times more potent than the parent compound. Flavin-containing monooxygenases are the primary enzymes mediating the biotransformation. Significant conversion of TG100435 to TG100855 has been observed in rat and dog after oral administration. Systemic exposure of TG100855 is 1.1- and 2.1-fold greater than that of TG100435 in rat and dog after oral dosing of TG100435. Since TG100435 is predominantly converted to the more potent N-oxide metabolite across species in vivo and in vitro, the overall tyrosine kinase inhibition in animal models may be substantially increased after oral administration of TG100435.     

On the interaction of small molecules with hemoglobin: orientational effects of hydration layers in protein crystal

The spin label TEMPO does not show a binding to hemoglobin molecule in solution. In the crystal however the spin label is bound and a considerable anisotropy in the ESR spectra is observed similar to that with covalent spin labeling. Since TEMPO is a small spherical molecule the anisotropy should be a consequence of the ordering in the crystal packing observed for the hydration layers. Besides the anisotropic sites (one per asymmetric unit) an isotropic signal is apparent. The population of these sites is sensitive to the temperature and above around 30 degrees C a transition is observed of the label from the anisotropic site to the isotropic one. This is consistent with a change in the hydration structure above this temperature so that the spin label is sensitive to the reorganization of water or crystallization. Results of simulations based on the relaxation theory in liquids are compared for different hemoglobin physical states: crystal, powder and solution. It is shown that the ESR parameters obtained in the crystal are very different from those used for spectral stimulation at low temperature.     

Exhaled nitric oxide measurement in workers in a microwave popcorn production plant

Airways obstruction in microwave-popcorn workers has been attributed to inhalation of flavoring agents. Two former workers at a microwave-popcorn plant were found by lung biopsy to have bronchiolitis obliterans. The study's aim was to determine whether exhaled nitric oxide (FENO) levels were associated with exposure levels, respiratory symptoms, or airways obstruction. A questionnaire, spirometry, and FENO measurements were completed by 135 workers. The FENO levels of workers with high flavoring exposures (n = 107) were compared with those of workers with low exposures (n = 28) and healthy external controls (n = 31). FENO levels were significantly lower in the high-exposure group (p < 0.05). There is no indication that FENO is useful as a marker of lung injury in a flavoring-exposed worker population with a substantial lung disease burden, but the finding of low FENO in the high-exposure group should not be dismissed.