SARS-CoV-2 seroprevalence in healthcare workers of a Swiss tertiary care centre at the end of the first wave: a cross-sectional study.

Objective: To assess the SARS-CoV-2 transmission in healthcare workers (HCWs) using seroprevalence as a surrogate marker of infection in our tertiary care centre according to exposure.

Design: Seroprevalence cross-sectional study.

Setting: Single centre at the end of the first COVID-19 wave in Lausanne, Switzerland.

DNA methylation profiling of esophageal adenocarcinoma using Methylation Ligation-dependent Macroarray (MLM).

Most types of cancer cells are characterized by aberrant methylation of promoter genes. In this study, we described a rapid, reproducible, and relatively inexpensive approach allowing the detection of multiple human methylated promoter genes from many tissue samples, without the need of bisulfite conversion. The Methylation Ligation-dependent Macroarray (MLM), an array-based analysis, was designed in order to measure methylation levels of 58 genes previously described as putative biomarkers of cancer.

Identification and molecular characterisation of Lausanne Institutional Biobank participants with familial hypercholesterolaemia - a proof-of-concept study.

Aims: We aimed to identify familial hypercholesterolaemia mutation carriers among participants to the Lausanne Institutional Biobank (BIL). Our experimental workflow was designed as a proof-of-concept demonstration of the resources and services provided by our integrated institutional clinical research support platform.

Methods: Familial hypercholesterolaemia was used as a model of a relatively common yet often underdiagnosed and inadequately treated Mendelian disease.

Bicc1 links the regulation of cAMP signaling in polycystic kidneys to microRNA-induced gene silencing.

Genetic defects in autosomal-dominant polycystic kidney disease (ADPKD) promote cystic growth of renal tubules, at least in part by stimulating the accumulation of cAMP. How renal cAMP levels are regulated is incompletely understood. We show that cAMP and the expression of its synthetic enzyme adenylate cyclase-6 (AC6) are up-regulated in cystic kidneys of Bicc1(-)(/-) knockout mice.

Bicaudal C, a novel regulator of Dvl signaling abutting RNA-processing bodies, controls cilia orientation and leftward flow.

Polycystic diseases and left-right (LR) axis malformations are frequently linked to cilia defects. Renal cysts also arise in mice and frogs lacking Bicaudal C (BicC), a conserved RNA-binding protein containing K-homology (KH) domains and a sterile alpha motif (SAM). However, a role for BicC in cilia function has not been demonstrated.

Imprinting of tumor-suppressor genes in human placenta.

Transcriptional deregulation in cancer has been shown to be associated with epigenetic alterations, in particular to tumor-suppressor- gene (TSG) promoters. In contrast, DNA methylation of TSGs is not considered to be present in normal differentiated cells. Nevertheless, we previously showed that the promoter of the tumor-suppressor gene APC is methylated, for one allele only, in normal gastric cells.

Epigenetic alteration of the Wnt inhibitory factor-1 promoter occurs early in the carcinogenesis of Barrett's esophagus.

The role of Wnt antagonists in the carcinogenesis of esophageal adenocarcinoma (EAC) remains unclear. We hypothesized that downregulation of the Wnt inhibitory factor-1 (WIF-1) might be involved in the neoplastic progression of Barrett's esophagus (BE). We analyzed the DNA methylation status of the WIF-1 promoter in normal, preneoplastic, and neoplastic samples from BE patients and in EAC cell lines.

Dual role of DNA methylation inside and outside of CTCF-binding regions in the transcriptional regulation of the telomerase hTERT gene.

Expression of hTERT is the major limiting factor for telomerase activity. We previously showed that methylation of the hTERT promoter is necessary for its transcription and that CTCF can repress hTERT transcription by binding to the first exon. In this study, we used electrophoretic mobility shift assay (EMSA) and chromatin immunoprecipitation (ChIP) to show that CTCF does not bind the methylated first exon of hTERT.

Unusual distribution of DNA methylation within the hTERT CpG island in tissues and cell lines.

The promoter region of the gene encoding the human telomerase reverse transcriptase (hTERT) is located in a CpG island and was shown to be regulated, at least in part, by DNA methylation. However, the observed correlation between hTERT methylation and gene expression was opposite to the general model of regulation by DNA methylation. We established a detailed mapping of methylcytosines at the CpG island (-1539 to +1732) surrounding the hTERT promoter in tissues and cell lines.

Demethylation of the human telomerase catalytic subunit (hTERT) gene promoter reduced hTERT expression and telomerase activity and shortened telomeres.

Telomerase is the ribonucleoproteic complex involved in maintaining telomere size. It is expressed in germ and stem cells but not in normal somatic cells. In most tumors, telomerase is reactivated.

The human telomerase RNA gene (hTERC) is regulated during carcinogenesis but is not dependent on DNA methylation.

Telomerase, the ribonucleoprotein complex involved in telomere maintenance, is composed of two main components: hTERT and hTERC. hTERT seems to be the rate-limiting factor for telomerase activity, although hTERC expression was also shown to correlate to a certain extent with telomerase reactivation. To determine whether the absence of hTERC expression could be the consequence of DNA methylation, we quantified hTERC RNA in 60 human samples (19 telomerase-negative normal tissues, nine telomerase-positive and 22 telomerase-negative tumor tissues, eight telomerase-positive and two telomerase-negative cell lines) using a quantitative dot blot on RT-PCR products.

Hypermethylation of the human telomerase catalytic subunit (hTERT) gene correlates with telomerase activity.

DNA methylation is an epigenetic process involved in embryonic development, differentiation and aging. It is 1 of the mechanisms resulting in gene silencing in carcinogenesis, especially in tumor suppressor genes (e.g.

Pitfalls in TRAP assay in routine detection of malignancy in effusions.

Telomerase has been found to be reactivated in a majority of cancers but is inactive in most somatic cells. Our principal goal was to determine the potential use of the telomeric repeat amplification protocol (TRAP) assay as marker for malignancy in cytological effusions. The simple selection criterion was the cytological diagnosis, and routine samples were classified into malignant (58 samples) and nonmalignant (233 samples).

Detection of malignant effusions: comparison of a telomerase assay and cytologic examination.

Telomerase is inactive in most somatic cells, but has been found to be reactivated in a majority of cancers. Our principal goal was to test whether the presence of telomerase activity concurred with positive cytology, and was thus of potential use in detecting cancer cells in effusions. The telomeric repeat amplification protocol (TRAP) assay and cytological examination were performed in a blinded fashion on 91 unselected effusions, for which laboratory processing was done according to standard procedures.

Human release factor eRF1: structural organisation of the unique functional gene on chromosome 5 and of the three processed pseudogenes.

In lower and higher eukaryotes, a family of tightly related proteins designated eRF1 (for eukaryotic release factor 1) catalyses termination of protein synthesis at all three stop codons. The human genome contains four eRF1 homologous sequences localised on chromosomes 5, 6, 7 and X. We report here the cloning and the structural analysis of the human eRF1 gene family.