Risk assessment of SARS-CoV-2 transmission in hospitality employees in a highly frequented tourist area.

Right from the start of the COVID pandemic in January 2020, the entire tourism sector was put under immense pressure because of its assumed role in SARS-CoV-2 transmission and infection dynamics. Based on reports of single superspreading events in the early days of the pandemic, the hotel industry appeared in a bad light that impaired a strategic risk-assessment of existing transmission risks between tourists and employees. We prospectively analysed samples of 679 employees of 21 hotels and restaurants from July 2020 to December 2020, a time during which more than 1.5 million tourists visited the Lübeck/Ostholstein Baltic Sea vacation area in Northern Germany. Employees were tested up to three times for an acute SARS-CoV-2 infection (PCR from nasopharyngeal swabs) and the presence of SARS-CoV-2 specific antibodies, and were asked to complete a short questionnaire. Despite the massive increase in tourist influx, no significant increase in SARS-CoV-2 cases was observed amongst employees of the tourism sector from July to September 2020. In a cluster-outbreak analysis of 104 study participants of one single hotel in the Lübeck/Ostholstein region in October 2020 being employed in the low-wage sector "housekeeping" could be determined as major risk factor for becoming infected. In conclusion, in a low incidence setting, touristic activities are safe under COVID-related hygiene measures for both the local population and employees of the tourism sector. Whereas, the field of work is a potential risk factor for increased infection dynamics.

Protective effect of endotoxin preconditioning in pancreas: analysis with DNA chip arrays.

Recently we demonstrated a protective effect of endotoxin preconditioning 24 hours before pancreatic ischemia-reperfusion injury, which has also been described for other organs. The mechanisms underlying this phenomenon, such as differential gene expression, are poorly investigated. We chose to approach this question by investigating differential gene expression in the rat pancreas over the time course of endotoxin pretreatment. Male Wistar rats (5 groups, 5 animals per group) were pretreated with endotoxin intraperitoneally (1 mg/kg of body weight). After treatment at 30 minutes, and at 3 and 24 hours the pancreas was removed. Untreated animals and animals with injection of saline solution served as controls. After RNA isolation, RNA was pooled and hybridized to Affymetrix chips to measure the relative mRNA levels of 7000 genes and 1000 expression sequence tags. Three hours after administration of endotoxin there was an activation of proinflammatory transcription factors and other proinflammatory genes. After 24 hours there was a clear decrease of these proinflammatory genes, but a remaining and increasing upregulation of important antiapoptotic genes, antiproteases, and other probably protective genes. There was also a significant upregulation of complement factors. It was surprising that heat-shock proteins and other typical immediate early genes of the AP-1 complex were not upregulated. Our data show that 24 hours after endotoxin stress there is a regulation of a network of genes that represents a multifaceted preconditioning. As most important factors, inhibition of apoptosis and antiproteatic strategies are identified. Heat-shock proteins seem to play no important role in the mechanism of endotoxin preconditioning.

[The extracellular matrix structure in keratoconus]. / Die Struktur der Extrazellulärmatrix bei Keratokonus.

PURPOSE: Keratoconus is a non-inflammatory disease characterized by progressive thinning of the central cornea. There are indications for an autosomal dominant heredity. Our purpose was to find correlations between gene expression and structural changes in extracellular matrix components. METHODS: Stromal RNA (keratoconus and comparison) was isolated from corneas, transformed to cRNA and analysed using biochips (Affymetrix). Structural investigations were performed by laser scanning and transmission electron microscopy. RESULTS: In keratoconus corneas there was an upregulation of different extracellular matrix components (collagen XV, metalloproteases) and a down-regulation of collagen IV (alpha1, alpha3) and versican. The morphological changes correlated to genetic obtained data. The orthogonal arrangement of the collagen fibrills (anteriorly and central) was altered in the collagen matrix of keratoconus corneas. CONCLUSIONS: The changes point on deregulation of the matrix arrangement. The interest in the cause of the disease is focused on the interfibrillar arrangement, the interaction between collagen and proteoglucanes.

[Gene expression in keratoconus. Initial results using DNA microarrays]. / Genexpression bei Keratokonus. Erster Einsatz von DNA-Microarrays.

INTRODUCTION: Keratoconus is a non-inflammatory ocular disease characterised by conical deformation, progressive thinning and scarring of the central cornea. Despite intensive investigations, the exact cause of the disease still remains unclear. Clinical studies provide strong indications of a major genetic role in the aetiology. We set out to examine the involvement in the manifestation of keratoconus of any of the 5,600 gene specificities available on the Affymetrix GeneChip HuGeneFL. METHODS: After examination of two corneas they were stored in RNAlater, RNA was extracted and hybridised on the chips. Using a combination of dyes it was possible to read the chips with laser detection and to visualise the gene expression pattern. RESULTS: We found an upregulation of collagens, versican, metalloproteinases and cell adhesion proteins. A downregulation was observed for TIGR protein, cytokeratins, eyes absent homologue (Eab1) and the proteins for radical treatment selenoprotein P and monooxygenase. CONCLUSIONS: Our results indicate that keratoconus is a process in which repair and scar-formation mechanisms operate at the same time. As candidate genes for this mechanism, collagen IV and related proteoglycans were favoured.

Human proteins IEF 58 and 57a are associated with the Golgi apparatus.

A mouse monoclonal antibody (mAB 22-II-D8B) raised against lysed transformed human amnion cells (AMA) has been characterized. The mAB decorated the Golgi apparatus in growing and quiescent cultured monolayer cells (fibroblasts and epithelial cells) of various species as determined by double immunofluorescence labeling and colocalization with galactosyltransferase antibodies. It reacted with the acidic human proteins IEF 58 (Mr = 29,000) and 57a, respectively (Mr = 30,000) (HeLa protein catalogue number; [(1982) Clin. Chem. 28, 766]), Golgi staining was also observed in BS-C-1 cells microinjected with mAB 22-II-D8B suggesting that the epitopes recognized by the antibody are most likely located on the cytoplasmic face of the membranes. The precise localization of the antigens to the various cisternae of the Golgi apparatus could not be demonstrated by immunogold cytochemistry on ultrathin cryosections due to either weak reactivity of the antibody or low concentration of the antigens. Immunofluorescence staining with mAB 22-II-D8B of lymphoid human Molt-4 cells and some human tissues failed to reveal any significant staining even though these expressed high levels of both IEF 58 and 57a. These results are taken to imply that the epitopes recognized by mAB 22-II-D8B may be masked in some cell types.

Bilirubin acidity. Titrimetric and 13C NMR studies.

Acidimetric titration of bilirubin IX-alpha, dissolved in excess aqueous sodium hydroxide, showed that two protons are dissociated with pK values well below 7 and that one or several additional acidic groups titrate with pK around 12.9. Precipitation of the nearly insoluble acid precluded determination of the two lower pK values by titration in aqueous solution. In dimethyl sulfoxide solution, four acidic protons were demonstrated, titrating two by two without precipitation. 13C NMR spectra of bilirubin IX-alpha were recorded and complete assignments were made by comparison with the spectra of bilirubin XIII-alpha and mesobilirubin etc. Such spectra, recorded after addition of 2 and 4 mol of base per mol of bilirubin IX-alpha, showed that both carboxyl groups are titrated by the first 2 mol of base, and both lactams by the following 2 mol of base. Cotitrations of bilirubin IX-alpha with other acids, o- and m-hydroxybenzoic acid and 2-pyridone, were used to determine relative pK values in dimethyl sulfoxide solution, and pK values for the four acidic protons of bilirubin IX-alpha in aqueous solution were calculated from the Born equation. Both carboxyl groups exhibited pK = 4.4, and both lactams pK = 13.0, in good agreement with values expected from the chemical structure of the bilirubin molecule. The implications of these findings for understanding the mechanism of bilirubin neurotoxicity are discussed.

Effects of tritiated thymidine on cell population kinetics.

This paper reports growth-kinetic data of Chinese Hamster tissue culture cells exposed at various times to differnt activities (0.05 muCi/ml up to 10.0 muCi/ml of tritiated thymidine. The analysis of the results aims at the determination of colony-size distribution and to the cellular capacity of reproduction after treatment which is reflected in the cell division spectrum within dialy intervals. The results of the growth-curves represented were converted into integrated curves of colony-size distribution, and their alteration as exponential curves for estimation of the cell cycle as a function of culture time was established. The recovery process and course determination of population kinetics following the 3H-TdR-treatments were evaluated.

[Development and application possibilities of a computer-controlled microspectrophotometric system for cytoanalysis (CYTOS)]. / Entwicklung und Anwendungsmöglichkeiten eines rechnerge-steurerten mikrospektrophotometrischen Systems zur Zytoanalytik (CYTOS).

A computer-assisted microspectrophotometric system for quantitative cell identification and data conversion, based on the scanned intracellular image pattern, will be introduced. The CYTOS system was developed with high flexibility for the analysis of general morphological and physiological problems of cell recognition and classification. The investigation include the quantitative transformation of extinction values in relation to cytomorphologic and cytochemical properties of a cell. In order to objectivate the subjective impression of visible or non-visible information, contained in a microscopic image, the measured extinction values were transformed in color values by a special developed interface. Each color shade corresponds to the intracellular substance concentration. The results, presented, concentrate on the CYTOS methodology, its application to the translation of data cytograms of DNA containing chromatic structures, and the intra-cytoplasmatic distribution pattern of enzyms. The CYTOS method might be considered as a useful technique revealing discrimination factors of diagnostical value.