PubMed Health⌕ Search

Biomedical subjects

F Grossmüller

Publications and source records attributed to F Grossmüller.

10 recordsLinked to original sources
PubMed2001

Influence of a transiently transfected gene on apoptosis, measurements guided by cotransfected GFP.

A rapid and quantitative flow cytometric method simultaneously identifying cells that incorporated a gene of interest in a transient electroporation and discriminating between dead, live and apoptotic states in a single measurement is presented. An expression vector encoding the gene of interest was cotransfected with a plasmid carrying the green fluorescent protein (GFP). Subsequently, the cultured cells were stained with 7-amino-actinomycin D (7-AAD) without fixation and were subjected to a multivariate analysis. The value of the method and its high reproducibility were demonstrated on Jurkat cells. Those cells were transiently transfected with a construct expressing a short C-terminal fragment of presenilin 1 (PS1-f) known to show anti-apoptotic properties. The PS1-f gene was under the control of the tetracycline-responsive transactivator.

Apoptosis↗
PubMed1996

Rapid identification of phosphopeptide ligands for SH2 domains. Screening of peptide libraries by fluorescence-activated bead sorting.

A method for the identification of high-affinity ligands to SH2 domains by fluorescence-activated bead sorting (FABS) was established. Recombinant SH2 domains, expressed as glutathione S-transferase (GST) fusion proteins, were incubated with a phosphotyrosine (Y*)-containing peptide library. 6.4 x 10(5) individual peptides of nine amino acids in length (EPX6Y*X19X7X19X7X6) were each displayed on beads. Phosphopeptide interaction of a given SH2 domain was monitored by binding of fluorescein isothiocyanate-labeled antibodies directed against GST. High-fluorescence beads were isolated by flow cytometric sorting. Subsequent pool sequencing of the selected beads revealed a distinct pattern of phosphotyrosine-containing motifs for each individual SH2 domain: the SH2 domain of the adapter protein Grb2 predominantly selected beads with the sequence Y*ENDP, whereas the C-terminal SH2 domain of the tyrosine kinase Syk selected Y*EELD, each motif representing the most frequently found residues C-terminal to the phosphotyrosine. For deconvolution studies, soluble phosphopeptides comprising variations of the Grb2 motifs were resynthesized and analyzed by surface plasmon resonance.

Amino Acid Sequence↗
PubMed1994

Light scatter based lymphocyte gate--helpful tool or source of error?

During flow cytometric analysis of 29 samples of human peripheral blood mononuclear cells, we observed that a light scatter-based lymphocyte gate would fail to cover all TCR (CD3)-expressing cells. A mean of 7.9 +/- 5.3% of all CD3+ cells was found outside the gate. In addition, this shifted cell subset showed an altered CD4/CD8 ratio (8.1 +/- 5.0% of all CD4+ and 13.7 +/- 5.8% of all CD8+ cells). The use of standard light scatter-based lymphocyte gates in acquisition and/or analysis of flow cytometry (FCM) data may thus lead to erroneous results, particularly if T cells are to be studied.

Artifacts↗
PubMed1978

Solid-phase radioimmunoassay method for determination of Escherichia coli enterotoxin.

The development of a solid-phase radioimmunoassay procedure for the determination of Escherichia coli enterotoxin(s) is described. Radioiodinated E. coli enterotoxin with about three radioiodine atoms per toxin molecule is, by the criterion of electrophoresis, identical to the unlabeled toxin. Goat anti-E. coli-enterotoxin antibody was coupled to polystyrene tubes and served as a solified toxin binder in the reported procedure. Various conditions necessary for the optimization and standardization of the solid-phase method were established. With the help of this technique it was possible to determine E. coli enterotoxin released from a porcine E. coli strain into culture medium.

Bacterial Toxins↗
PubMed1978

Highly sensitive solid-phase radioimmunoassay suitable for determination of low amounts of cholera toxin and cholera toxin antibodies.

A direct solid-phase radioimmunoassay procedure was developed for the determination of cholera toxin and cholera toxin antibody. The reported method employed anti-choleragenoid antibody attached to polystyrene tubes as a solidified binder for cholera toxin. The binding of radioidinated cholera toxin on its solidified antibody was inhibitable by unlabeled cholera toxin and cholera toxin antibody. With the help of this method, the heat stability of cholera toxin was also studied. Radioiodinated cholera toxin was shown to be labeled in both of its subunits. The stability of the iodinated cholera toxin at the reported specific radioactivity is remarkable. It was found that the labeled cholera toxin can be used in the solid-phase radioimmunoassay even 4 months after iodination.

Antitoxins↗
PubMed1971

Some quantitative aspects of the labelling of proteins with 125 I by the iodine monochloride method.

The labelling of proteins by the iodine monochloride method was studied by using a mathematical model. The equations used were primarily derived from the mass law equation of the isotopic exchange reaction between [(125)I]iodide and iodine monochloride. For convenient application, all equations were programmed into a computing desk-top calculator. To support the validity of the theoretical model, a series of iodinations of insulin were performed under various labelling conditions. The results of these experiments compare well with the theoretically derived values. Deviations from the theoretical values occurring at molar ratios of [(125)I]iodide to iodine monochloride < 0.1 and > 4.0 are explained and suggestions made about how to prevent them. The mathematical model was used to simulate the isotopic exchange, and the iodination reaction under various conditions, to study (a) the influence of the amount of [(125)I]iodide on the amount of [(125)I]iodine monochloride formed, (b) the influence of the specific radioactivity of [(125)I]iodide on the amount of [(125)I]iodine monochloride formed, and (c) the influence of the specific radioactivity of [(125)I]iodide on the number of millicuries needed for labelling to a desired extent.

Chlorides↗