Construction and evaluation of yeast expression networks by database-guided predictions.

DNA-Microarrays are powerful tools to obtain expression data on the genome-wide scale. We performed microarray experiments to elucidate the transcriptional networks, which are up- or down-regulated in response to the expression of toxic polyglutamine proteins in yeast. Such experiments initially generate hit lists containing differentially expressed genes. To look into transcriptional responses, we constructed networks from these genes. We therefore developed an algorithm, which is capable of dealing with very small numbers of microarrays by clustering the hits based on co-regulatory relationships obtained from the SPELL database. Here, we evaluate this algorithm according to several criteria and further develop its statistical capabilities. Initially, we define how the number of SPELL-derived co-regulated genes and the number of input hits influences the quality of the networks. We then show the ability of our networks to accurately predict further differentially expressed genes. Including these predicted genes into the networks improves the network quality and allows quantifying the predictive strength of the networks based on a newly implemented scoring method. We find that this approach is useful for our own experimental data sets and also for many other data sets which we tested from the SPELL microarray database. Furthermore, the clusters obtained by the described algorithm greatly improve the assignment to biological processes and transcription factors for the individual clusters. Thus, the described clustering approach, which will be available through the ClusterEx web interface, and the evaluation parameters derived from it represent valuable tools for the fast and informative analysis of yeast microarray data.

10 years quality assurance of the dermatologist's procedure. ABD review board part II: 2003-2009.

BACKGROUND: The dermatologist's procedure ("procedure for early detection of occupational skin diseases") enables dermatologists to conduct the relevant diagnostics at the expenses of the statutory employers' liability insurance funds (UVT) if there is a possibility of a work-related skin disorder in an employee. Acceptance of this most relevant tool for secondary prevention in occupational dermatology in Germany is high and most dermatologists make careful use of this unparalleled privilege. However, there have been occasional complaints by the UVT, concerning overly extensive diagnostics. Consequently, the Task Force on Occupational and Environmental Dermatology (ABD) of the German Society of Dermatology set up a review board in May 1999. RESULTS: Dermatologists' reports in question were submitted by the UVT to the review board and reviewed separately by two experienced occupational dermatologists both in the 1(st) period (1999-2003) and now in the second period (June 2003 - November 2009). The criticism of the reviewers was mostly directed towards the number of tests and an insufficient documentation in the dermatologist's report. There were 69 dermatologists' reports submitted to the review board (as compared to 155 in the 1(st) period). CONCLUSIONS: The decreased number of dermatologists' reports submitted could be a result of the review process itself. Other factors may include the optimization of the dermatologist's report with a better reimbursement as well as the recent publication of guidelines and continuous education in occupational dermatology with certification of more than 700 dermatologists. These measures of quality assurance are aimed to further optimize the dermatologist's procedure and to allow for improved and more rapid care for patients with occupational dermatoses by dermatologists.

Controlling surface functionality through generation of thiol groups in a self-assembled monolayer.

A lithographic method to generate reactive thiol groups on functionalized synthetic diamond for biosensor and molecular electronic applications is developed. We demonstrate that ultrananocrystalline diamond (UNCD) thin films covalently functionalized with surface-generated thiol groups allow controlled thiol-disulfide exchange surface hybridization processes. The generation of the thiol functional head groups was obtained by irradiating phenylsulfonic acid (PSA) monolayers on UNCD surfaces. The conversion of the functional headgroup of the self-assembled monolayer was verified by using X-ray photoelectron spectroscopy (XPS), near-edge X-ray absorption fine structure (NEXAFS), and fluorescence microscopy. Our findings indicate the selective generation of reactive thiol surface groups. Furthermore, we demonstrate the grafting of yeast cytochrome c to the thiol-modified diamond surface and the electron transfer between protein and electrode.

[Four years of quality assurance of dermatologic procedures: report from the ABD clearing institution]. / Vier Jahre Qualitätssicherung im Hautarztverfahren: Bericht aus der Clearingstelle der ABD.

BACKGROUND: Expert dermatologic evaluation is the most relevant tool for secondary prevention in occupational dermatology in Germany. If there is a possibility of a work-related skin disorder in an employee, dermatologists may conduct the relevant diagnostic procedures (e.g. patch-and prick-tests, serology) at the expenses of the public employers' liability insurance fund (UVT). Most dermatologists make careful use of this unparalleled privilege, which is also an obligation. However, recently, with an increasing number of dermatologist's reports submitted, there have been occasional complaints by the UVT concerning overly extensive testing. In 1999 the Task Force on Occupational and Environmental Dermatology (ABD) of the German Dermatological Society established a clearing procedure. Two experienced occupational dermatologists will--separately--give their expert opinion on dermatologist's reports which have been forwarded anonymously by the UVT for expert review. RESULTS: Thus far, from May 1999 to May 2003 155 dermatologist's reports have been submitted to the clearing procedure. The complaints were in > 95% of cases considered justified by the experts. Their criticism was primarily directed towards excessive testing procedures and failure to provide sufficient clinical information. CONCLUSIONS: The UVT does not undertake such extensive preventive efforts for any other occupational disease. Therefore, quality management of the dermatologist's procedure--conducted by dermatologists and providing transparency--is essential to maintain and develop this effective tool of secondary prevention for the benefit of workers and employers.

Patch testing with components of water-based metalworking fluids.

Water-based metalworking fluids (MWFs) may cause both irritant and allergic contact dermatitis. Several well-known MWF allergens are available for patch testing, but considering the wide variety of possible components used in MWF, our diagnostic arsenal covers only a small part of potential allergens. We therefore selected 13 frequently used MWF components that might be sensitizers and had not yet been tested routinely. In 5 centres, 233 dermatitis patients with present or past occupational exposure to MWF were patch tested with this and other panels. Only 7 patients showed positive reactions to the study panel. Allergic reactions to the emulsifier diglycolamine [syn. 2-(2-aminoethoxy) ethanol] were seen in 5 patients, and 1 patient each reacted positively to 2-amino-2-ethyl-1,3-propanediol (AEPD) and methyldiethanolamine (MDEA). Clinical relevance of the reactions to diglycolamine was unequivocally proven by its presence in the MWF from the patients' workplace in 3 cases. Diglycolamine seems to be an important MWF allergen, independently from monoethanolamine and diethanolamine. A test concentration of 1% petrolatum (pet.) appears to be appropriate. The importance of AEPD and MDEA as MWF allergens still remains to be established. The lack of positive test reactions to the other MWF components tested may be due to their low-sensitizing potential or too low a patch test concentration being used.