Risikokommunikation zum Schutz vor Gefahrstoffen am Arbeitsplatz

Bundesgesundheitsblatt - Gesundheitsforschung - Gesundheitsschutz - Gefahrstoffe sind in der Arbeitswelt allgegenwärtig. Beschäftigte aus allen Branchen sind bei ihrer Arbeit mit...     

Einfach und praktisch: rechtliche Grundlagen und Verhalten an Einsatzorten mit Verstorbenen

Notfall + Rettungsmedizin -     

Effectiveness of maxillary protraction using a hybrid hyrax-facemask combination: A controlled clinical study

Objective:To evaluate the treatment effects of a hybrid hyrax-facemask (FM) combination in growing Class III patients.Material and Methods:A sample of 16 prepubertal patients (mean age, 9.5 ± 1.6 years) was investigated by means of pre- and posttreatment cephalograms. The treatment comprised rapid palatal expansion with a hybrid hyrax, a bone- and toothborne device. Simultaneously, maxillary protraction using an FM was performed. Mean treatment duration was 5.8 ± 1.6 months. The treatment group was compared with a matched control group of 16 untreated Class III subjects. Statistical comparisons were performed with the Mann-Whitney U-test.Results:Significant improvement in skeletal sagittal values could be observed in the treatment group over controls: SNA: 2.4°, SNB: −1.7°, Co-Gn: −2.3 mm, Wits appraisal: 4.5 mm. Regarding vertical changes, maintenance of vertical growth was obtained as shown by a small nonsignificant increase of FMA and a small significant decrease of the Co-Go-Me angle.Conclusions:The hybrid hyrax-FM combination was found to be effective for orthopedic treatment in growing Class III patients in the short term. Favorable skeletal changes were observed both in the maxilla and in the mandible. No dentoalveolar compensations were found.     

Mini-implant stability at the initial healing period: A clinical pilot study

Objective:To evaluate the changes of mini-implant stability over the initial healing period in humans.Material and Methods:A sample of 19 consecutively treated patients (mean age 15.5 ± 7.3 years) was examined. In each patient, a mini-implant of a size of 2 × 9 mm was inserted into the anterior palate. Implant stability was assessed using resonance frequency analysis (RFA) immediately after insertion (T0), 2 weeks later (T1), 4 weeks later (T2), and 6 weeks later (T3). Insertion depth (ID) and the maximum insertion torque (IT) were measured. Data were tested for correlations between RFA, ID, and IT. All RFA values were tested for statistically significant differences between the different times.Results:The mean ID was 7.5 ± 0.6 mm, and the mean IT was 16.8 ± 0.6 Ncm. A correlation was found between RFA and ID (r  =  .726, P < .0001), whereas no correlations between RFA and IT or between IT and ID were observed. From T0 to T1, the stability (36.1 ± 6.1 implant stability quotient [ISQ]) decreased nonsignificantly by 4.9 ± 6.1 ISQ values (P > .05). Between T1 and T2, the stability decreased highly significantly (P < .001) by 7.9 ± 5.9 ISQ values. From T2 on, RFA remained nearly unchanged (−1.7 ± 3.5 ISQ; P > .05).Conclusions:Mini-implant stability is subject to changes during the healing process. During weeks 3 and 4, a significant decrease of the stability was observed. After 4 weeks, the stability did not change significantly.     

Molecular typing and in vitro resistance of Cryptococcus neoformans clinical isolates obtained in Germany between 2011 and 2017

Cryptococcosis is a fungal infection of the central nervous system predominantly caused by Cryptococcus neoformans in immunocompromised patients. In several countries worldwide, up to 50% of isolates show in vitro resistance to clinically used antifungals including fluconazole. No prospective data on susceptibility to antifungal drugs are available for Germany. In this study, we characterised all C. neoformans isolates collected from individual patients’ samples at the German reference laboratory for cryptococcosis 2011 and 2017 (n = 133) by multi-locus sequence typing and phenotypic drug susceptibility testing. We identified serotype A/genotype VNI isolates belonging to clonal complexes previously described from Europe, Africa, Asia and South America as the most prevalent agents of cryptococcosis in Germany. Overall, we observed minimal inhibitory concentrations (MICs) above the epidemiological cut-offs (ECVs) in 1.6% of isolates regarding fluconazole and 2.3% of isolates regarding 5-flucytosine. Here, two C. neoformans var. grubii isolates displayed decreased drug susceptibility to fluconazole, one of them additionally to 5-flucytosine. We also found 5-flucytosine MICs above the ECV for two C. neoformans var. neoformans isolates. We identified a novel mutation in the ERG11 gene which might be associated with the elevated fluconazole MIC in one of the isolates. The clinical importance of the detected in vitro resistance is documented by patient histories showing relapsed infection or primary fatal disease. Of note, sertraline demonstrated antifungal activity comparable to previous reports. Systematic collection of susceptibility data in combination with molecular typing of C. neoformans is important to comprehensively assess the spread of isolates and to understand their drug resistance patterns.     

Radiographic guided drilling of bony tibial tunnels for fixation of meniscus transplants using percentage references

The objective of our investigation was to evaluate the precision of radiographic-guided tibial tunnel drilling for anatomical anchoring of meniscus transplants at the tibial insertion areas. In 20 cadaveric proximal tibiae, the meniscal insertions were dissected and their circumferences outlined. Standardized photographs of the tibial plateau were obtained. Applying established percentage values for radiographic determination of the meniscus insertion midpoints, tibial tunnels were drilled using a standard ACL-guide. Guide positioning was performed by using the midpoints as determined on standard AP and lateral radiographs. After tibial tunnel drilling, a second set of standardized photographs of the tibial plateau was obtained. Digital imaging permitted the superposition of pre- and postoperative images. Overlapping between the anatomical insertion areas and the tibial tunnel exit was determined, as well as the distance between the borders of the insertion areas and the tunnel exit. Insertion area and tunnel exit showed a mean overlapping of 59.8 ± 34.8% (anterior horn), respectively 62.4 ± 32.0% (posterior horn) for the lateral meniscus and of 88.4 ± 15.5% (anterior horn), respectively 60.3 ± 31.6% (posterior horn) for the medial meniscus. Mean distance between the borders of insertion area and tunnel exit was 2.0 ± 1.5 mm (anterior horn), respectively 2.0 ± 1.7 mm (posterior horn) for the lateral meniscus and 0.9 ± 0.9 mm (anterior horn), respectively 2.1 ± 1.4 mm (posterior horn) for the medial meniscus. Thus, a precise drilling of tibial tunnels at the anatomical insertions of the menisci can be obtained by positioning a standard ACL-guide under radiographic control in a cadaver setting. In advanced day-by-day clinic, this knowledge could facilitate the surgical technique for anatomical fixation of lateral and medial meniscus transplants.     

Quantitative tissue oxygen measurement in multiple organs using 19F MRI in a rat model

Measurement of individual organ tissue oxygen levels can provide information to help evaluate and optimize medical interventions in many areas including wound healing, resuscitation strategies, and cancer therapeutics. Echo planar ¹⁹F MRI has previously focused on tumor oxygen measurement at low oxygen levels (pO₂) <30 mmHg. It uses the linear relationship between spin‐lattice relaxation rate (R₁) of hexafluorobenzene (HFB) and pO₂. The feasibility of this technique for a wider range of pO₂values and individual organ tissue pO₂ measurement was investigated in a rat model. Spin‐lattice relaxation times (T₁= 1/R₁) of hexafluorobenzene were measured using ¹⁹F saturation recovery echo planar imaging. Initial in vitro studies validated the linear relationship between R₁ and pO₂ from 0 to 760 mmHg oxygen partial pressure at 25, 37, and 41°C at 7 Tesla for hexafluorobenzene. In vivo experiments measured rat tissue oxygen (ptO2) levels of brain, kidney, liver, gut, muscle, and skin during inhalation of both 30 and 100% oxygen. All organ ptO₂ values significantly increased with hyperoxia (P < 0.001). This study demonstrates that ¹⁹F MRI of hexafluorobenzene offers a feasible tool to measure regional ptO2 in vivo, and that hyperoxia significantly increases ptO2 of multiple organs in a rat model. Magn Reson Med, 2011. © 2011 Wiley Periodicals, Inc.     

Tracheal transplantation: demonstration of HLA class II subregion gene products on human trachea

The present morphological study was designed to investigate the expression of HLA class II subregion gene products on human trachea. Frozen sections from the tracheas of 20 cadavers not suffering from ear, nose or throat diseases were studied immunohistochemically using monoclonal antibodies which recognize monomorphic determinants of HLA-DR, -DP and -DQ molecules. Positive reactions could be detected in the airway epithelium and mixed glands. HLA-DR and -DP showed a stronger presence than HLA-DQ. Our results indicate that tracheal mucosa may be the major antigenic structure of the trachea and therefore responsible for the immunogenic action of allogenic tracheal transplants.     

Detection of class II antigens on human nasal cartilage

The presence and distribution of class II antigens on human nasal cartilage was investigated using monoclonal antibodies directed against HLA-DR, HLA-DP, and HLA-DQ molecules. Tissue sections and chondrocytes in suspension were prepared for immunoperoxidase staining and flow cytometric analysis. Class II antigens were detected primarily on the perichondrium. In contrast, chondrocytes, either isolated or in tissue sections, were completely negative, suggesting that cells of the perichondrium, may, by themselves, be capable of initiating a rejection process.