Constructing networks for comparison of collagen types.

Collagens are structural proteins that are predominantly found in the extracellular matrix of multicellular animals, where they are mainly responsible for the stability and structural integrity of various tissues. All collagens contain polypeptide strands (α-chains). There are several types of collagens, some of which differ significantly in form, function, and tissue specificity. Because of their importance in clinical research, they are grouped into subdivisions, the so-called collagen families, and their sequences are often analysed. However, problems arise with highly homologous sequence segments. To increase the accuracy of collagen classification and prediction of their functions, the structure of these collagens and their expression in different tissues could result in a better focus on sequence segments of interest. Here, we analyse collagen families with different levels of conservation. As a result, clusters with high interconnectivity can be found, such as the fibrillar collagens, the COL4 network-forming collagens, and the COL9 FACITs. Furthermore, a large cluster between network-forming, FACIT, and COL28a1 α-chains is formed with COL6a3 as a major hub node. The formation of clusters also signifies, why it is important to always analyse the α-chains and why structural changes can have a wide range of effects on the body.

Hearing assessment in dental practitioners and other academic professionals from an urban setting.

INTRODUCTION: Extended exposure to high-speed handpieces and other noise-intensive devices might put dentists at risk for possible hearing impairment. The aim of this study was to determine the hearing ability of dentists and other scientists for comparison. METHODS: After approval by the ethics committee, 115 subjects (dentists and other academic professionals as controls) of both genders were enrolled in the study. Exclusion criteria were colds, ear-blockages or abnormal hearing-thresholds. An audiometric determination (Oscilla USB audiometer, AudioConsole 3, Inmedico A/S, Denmark) was performed in the frequency range of 125 Hz to 8 kHz for both ears. Anamnestic data and number of years in the profession were assessed using a questionnaire. Differences between groups were analyzed with the Mann-Whitney-U-test. RESULTS: Data from 53 dentists and 55 other academic professionals (69.4% male, 30.6% female) with a mean age of 51.7 ± 9.6 years and similar gender distributions in both groups were analyzed. The audiometric tests for the right and left air conduction showed that the hearing of dentists tended to be slightly more impaired than in the control subjects. For the frequencies 3 kHz and 4 kHz these differences were statistically significant for both ears. In contrast, no significant differences were found in this range for bone conduction. CONCLUSIONS: Hearing impairment in dentists was slightly higher than in controls. Although other factors like environmental noise exposure were comparable for both groups, occupational exposure to high-speed handpieces and other noisy devices can be an additional burden for the hearing.