Search PubMed⌕ Search

Biomedical subjects

U Lüthi

Publications and source records attributed to U Lüthi.

At least 19 recordsLinked to original sources
PubMed2006

Manufacture of a cell-free amnion matrix scaffold that supports amnion cell outgrowth in vitro.

We manufactured a cell-free extracellular matrix scaffolds in order to obtain a support material for amnion cell outgrowth, eventually being used for repair of prematurely ruptured fetal membrane. Human preterm or term amnion tissue was separated into its collagenous extracellular matrix and cell components. The acellular scaffold was explored for its capacity to support regrowth of isolated human amnion epithelial or mesenchymal cells in vitro. The outgrowth of amnion cells on and in the scaffold was investigated by scanning and transmission electron microscopy, and confocal laser scanning microscopy. Cell-free amnion matrix scaffolds demonstrated a porous collagen fiber network similar as in native amnion. Inoculation of acellular amnion scaffolds with human amnion cells revealed that its property to support amnion cell outgrowth was retained. Amnion epithelial and mesenchymal cells were found to grow into dense layers on the surface of the scaffold within 3-4 days and 7-8 days, respectively, and to some extent, invaded the scaffold during the culture period. Manufactured acellular amnion matrix retains structural and functional properties required for cell outgrowth in vitro. It may become useful to repair prematurely ruptured fetal membranes.

Amnion↗
PubMed2006

[Metaanalysis of reference values in hematology].

The reference values of the most commonly used parameters in hematology were evaluated in a metaanalysis using practices of a group of major hospitals in Switzerland and in detail review of the literature. Extensive differences of the reference values have been noted being caused mainly by selection of different patient/control collectives. Whenever possible, reference values were separately evaluated for age, gender and race. The reported reference values approximated a Gauss distribution allowing for statistical evaluation accordingly. Due to recent standardization (ICSH and NCCLS), differences caused by instrumentation and preanalytics were found to be of less importance. Our presented validated reference values in hematology should allow for better discrimination of classical hematological disease entities such as an iron deficiency anemia, thalassemia and hemolysis.

Blood Cell Count↗
PubMed2004

[Blast cells in peripheral blood smear].

Despite modern technologies such as immunophenotyping and molecular probing cytomorphological examination of stained peripheral blood smears by microscopy remains the mainstay of diagnosis in a large variety of diseases. Although technically simple morphological analysis requires considerable skill. Early diagnosis in several hematological diseases is important (for example acute promyelocytic leukaemia associated frequently with disseminated intravascular coagulation), in order to initiate adjusted therapy. Further, referral of the patient to tertiary care centers is only justified after a solid diagnosis is obtained. Many disorders can be diagnosed by pathognomonic blood smears. The present article is a short overview of important hematological disorders, which are associated with blast cells in the peripheral blood. Important morphological cell characteristics are illustrated by microscopic pictures.

Blast Crisis↗
PubMed2004

[Classification of neoplastic disorders of the haematopoietic system].

The present article is written in an attempt to illustrate the ongoing diagnostic progress by presenting some examples of pre-existing and newly defined entities. The World Health Organisation proposed in 2001 a "Classification of Tumours of the Haematopoietic and Lymphoid Tissues". Relying on the broadest consensus possible, it received high acclamation by both clinicians and pathologists. The approach is based on cell lineage assignment including morphology and immunophenotype, but also relies on cytogenetic and clinical features in order to define disease entities to an extent as far as possible. The diagnostic criteria for myeloid, lymphoid and histiocytic neoplasms have been compiled by an international group of 51 experts assembled in ten disease-related committees. In order to cover the interests of daily haematological practice, selected topics are focussed including chronic and acute myeloid neoplasias, precursor lymphoid neoplasias, mature B-, T- and NK-cell lymphomas, Hodgkin lymphoma as well as histiocytic and dendritic cell neoplasias.

Hematologic Neoplasms↗
PubMed2001

Functional analysis of the p300 acetyltransferase domain: the PHD finger of p300 but not of CBP is dispensable for enzymatic activity.

Acetylation of nucleosomal histones is a major regulatory step during activation of eukaryotic gene expression. Among the known acetyltransferase (AT) families, the structure-function relationship of the GNAT superfamily is the most well understood. In contrast, less information is available regarding mechanistic and regulatory aspects of p300/CBP AT function. In this paper, we investigate in closer detail the structure and sequence requirements for p300/CBP enzymatic activity. Unexpectedly, we find that the PHD finger of p300, but not of CBP, is dispensable for AT activity. In order to identify residues involved in substrate or acetyl-coenzyme A (acetyl-CoA) recognition, we have introduced 19 different amino acid substitutions in segments that are highly conserved between animal and plant p300/CBP proteins. By performing acetylation reactions with histones, a p53 peptide or the AT domain itself, we define several residues required for histone and p53 substrate recruitment but not for acetyl-CoA binding. Finally, we show that identical mutations in the p300 and CBP AT domain impair AT activity differently. This latter result combined with the finding of a differential requirement for the PHD finger provides evidence for structural differences between p300 and CBP that may in part underlie a previously reported functional specialization of the two proteins.

Acetyl Coenzyme A↗
PubMed2001

Plant orthologs of p300/CBP: conservation of a core domain in metazoan p300/CBP acetyltransferase-related proteins.

p300 and CBP participate as transcriptional coregulators in the execution of a wide spectrum of cellular gene expression programs controlling cell differentiation, growth and homeostasis. Both proteins act together with sequence-specific transcription factors to modify chromatin structure of target genes via their intrinsic acetyltransferase activity directed towards core histones and some transcription factors. So far, p300-related proteins have been described in animals ranging from Drosophila and Caenorhabditis elegans to humans. In this report, we describe p300/CBP-like polypeptides in the plant Arabidopsis thaliana. Interestingly, homology between animal and plant p300/CBP is largely restricted to a C-terminal segment, about 600 amino acids in length, which encompasses acetyltransferase and E1A-binding domains. We have examined whether this conservation in sequence is paralleled by a conservation in function. The same amino acid residues critical for acetyltransferase activity in human p300 are also critical for the function of one of the plant orthologs. Remarkably, plant proteins bind to the adenovirus E1A protein in a manner recapitulating the binding specificity of mammalian p300/CBP. The striking conservation of an extended segment of p300/CBP suggests that it may constitute a functional entity fulfilling functions that may be essential for all metazoan organisms.

Acetyltransferases↗