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Summary The aim of the present in vitro study was to evaluate the effect of carbamide peroxide (CP) bleaching on fluoride uptake in enamel. Additionally, the susceptibility for erosion in bleached and fluoridated enamel was tested. Each four enamel specimens were prepared from 44 bovine incisors. The four samples gained from each tooth were distributed among four groups (A–D) of 44 specimens each: A: (unbleached/unfluoridated) served for determination of baseline fluoride concentration; B: (unbleached/fluoridated) four times in 2000 ppm NaF solution (2 min); C: (bleached/unfluoridated) four times in 10% CP (8 h); D: (bleached/fluoridated) four times in 10% CP and fluoridation. In 22 specimens of each group both KOH-soluble and structurally bound fluoride were determined in the outermost 30 μm of the enamel. In the remaining specimens erosions were induced by immersing the samples in 5 mL of 1% citric acid (20 min) and microhardness was evaluated before and after demineralization. Statistical analysis showed that KOH-soluble fluoride uptake was similar for group B and D specimens. Structurally bound fluoride uptake after fluoride application in unbleached samples was significantly higher than in bleached ones. Bleaching only resulted in a highly significant fluoride loss. In all samples erosion caused a significant microhardness loss. The study showed that pre-treatment of enamel with CP followed by fluoridation does not improve erosive resistance. Moreover the study reveals that CP treatment decreases concentration of structurally bound fluoride in enamel which could not be outweighed by fluoridation with 2000 ppm NaF. It is concluded that it is not feasible to improve fluoride uptake in enamel with a pre-treatment with 10% CP. [ABSTRACT FROM AUTHOR]

Twenty-four cases of adenoid cystic carcinoma from the Salivary Gland Registry of the University of Hamburg were analysed with respect of their differentiation and subclassification. With immunohistochemical methods, several groups of marker substances were analysed in these tumors: marker for a glandular function; immunoglobulins; metalloproteins; tumor markers; substances associated with the basal membrane and carbohydrate chains. The following patterns of histological differentiation were found: cribriform pattern with typical pseudocysts; tubular pattern with ductal elements; trabecular pattern with predominance of hyalininzed stromal elements; basaloid pattern with low differentiated cells. For every pattern, a special immunohistochemical profile could be established. The morphological and immunohistochemical analysis revealed the following relation between the different patterns: Origin of the malignant proliferation is presumably the terminal ductal system of the salivary glans (indifferent cell of the reserve cell type). This cell can differentiate in 2 directions: a myoepithelial and a ductal cell type. Immunohistochemically, the presence of basement membrane-associated substances is accompanied by the appearance of myoepithelial-like cells. The presence of secretory products is a feature of ductal cells. [ABSTRACT FROM AUTHOR]

There is a general agreement that blood alcohol concentrations (BACs) of about 0.05% result in impairment of the ability to drive. This fact has been supported by means of experiments. In addition, there are only a few studies to date investigating low BACs. The present study aims to investigate the extent and quality of cognitive changes in low BACs of around 0.03%. Sixteen healthy male subjects were examined in a double-blind, placebo-controlled study. During the trials the BAC was regulated to about 0.03%. As part of the study a record was made of the general level of intelligence, subjective impairments, possible depressive symptoms, general ability to perform, vigilance, divided attention, response times and performance of memory. Statistical analysis took place using the two-period crossover design. Verbal intelligence, general performance, vigilance (optical stimuli), divided attention, vigilance towards acoustic stimuli and the general response time to acoustic and visual-acoustic sequential stimuli, and memory were not impaired significantly by a BAC of around 0.03%. The total response and motor response time to optical stimuli as well as decision time about sequential optical stimuli were, however, significantly changed for BACs of around 0.03%. In conclusion, the present results show that already in BACs of around 0.03%, particular cognitive functions which rely on perception and processing of visual information, are significantly impaired. This was evident in the more complex and urgent tasks.