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P Lüthy

Publications and source records attributed to P Lüthy.

17 recordsLinked to original sources
PubMed1993

[Role of transesophageal echocardiography in the diagnosis of cardiac disorders].

Transesophageal echocardiography provides a new window for ultrasound examination of the heart. The approach allows ultrasonic access to the heart in patients with transthoracic images of inadequate quality. Furthermore, transesophageal examination may provide information additional to that from the conventional transthoracic approach in the search for lesions including complications of endocarditis, mitral prosthesis dysfunction, aortic dissection, embolism of cardiac origin and selected cardiac malformations.

Echocardiography, Transesophageal↗
PubMed1988

Binding of the delta endotoxin from Bacillus thuringiensis to brush-border membrane vesicles of the cabbage butterfly (Pieris brassicae).

The insecticidal delta endotoxin of Bacillus thuringiensis was labeled with iodine-125. Brush-border membrane vesicles, prepared from the midgut epithelium of Pieris brassicae larvae, known to be highly susceptible to the toxin, and from a non-target tissue: the small intestine of rat, were examined for binding of 125I-toxin. The toxin was bound specifically only to insect vesicles. Its binding to the insect membrane system was competitively inhibited by 127I-toxin and non-iodinated toxin, whereas the binding of the 125I-toxin to the mammalian membrane system was not affected by unlabeled toxin. Vesicles of P. brassicae possess two individual binding-site populations for iodinated toxin with dissociation constants of 46 nM and 490 nM. The Hill coefficients of both sites were approximately 1 and the binding capacities were 0.2 pmol and 30 pmol/mg vesicle protein for the high and the low-affinity sites respectively. The estimation of the dissociation constant for non-iodinated toxin, using a competition experiment, revealed only one binding-site population which possessed a dissociation constant of 235 nM. It is concluded that this is the binding site for the native toxin. This site was sensitive towards treatment with proteases or mixed glycosidases. It is suggested that it is a protein or a glycoprotein.

Animals↗
PubMed1988

Assessment of myocardial metabolism with iodine-123 heptadecanoic acid: effect of decreased fatty acid oxidation on deiodination.

Terminally radioiodinated fatty acid analogs are of potential use for the noninvasive delineation of regional alterations of fatty acid metabolism by gamma imaging. Since radioactivity from extracted iodine-123 heptadecanoic acid [( 123I]HDA) is released from the myocardium in form of free radioiodide (123I-) the present study was performed to determine whether deiodination of [123I]HDA is related to free fatty acid metabolism. Myocardial production of free radioiodide was measured in rat hearts in vitro and in vivo both under control conditions and after inhibition of fatty acid oxidation. In isolated rat hearts perfused at constant flow with a medium containing [123I]HDA, release of 123I- was markedly reduced during cardioplegia and pharmacologic inhibition of mitochondrial fatty acid transfer with POCA by 67% (p less than 0.005) and 72% (p less than 0.005), respectively. In fasted rats in vivo, 1 min after i.v. injection of [123I]HDA, 51 +/- 5% of myocardial radioactivity was recovered in the aqueous phase, containing free iodide, of myocardial lipid extracts. Aqueous activity was significantly decreased in fed (20 +/- 2%; p less than 0.002) and POCA pretreated (30 +/- 3.7%; p less than 0.05) animals exhibiting reduced oxidation of [14C]palmitate. Thus, deiodination of [123I]HDA was consistently reduced during inhibition of fatty acid oxidation in vitro and in vivo. The results apply to the interpretation of myocardial clearance curves of terminally radioiodinated fatty acid analogs.

Animals↗
PubMed1986

Binding and activity of Bacillus thuringiensis delta-endotoxin to invertebrate cells.

Fluorescein isothiocyanate was used as a label to detect delta-endotoxin of Bacillus thuringiensis subsp. thuringiensis and israelensis in binding studies with different in vitro cell systems. Protoxin of the subspecies thuringiensis could be labelled directly whereas the activated toxin had to be traced indirectly with labelled antibodies. Both protoxin and activated toxin bound to primary midgut cell cultures of Pieris brassicae larvae as well as to cells of an established culture of Drosophila melanogaster. No binding with either toxin form could be observed with hemocytes of P. brassicae. Biological activity as shown by the trypan blue viability assay was obtained only with the activated toxin against the midgut cells. Toxin of the subspecies israelensis reacted very unspecifically. Binding followed by rapid destruction was obtained with all the tested cultures.

Animals↗
PubMed1984

Introduction of plasmid pC194 into Bacillus thuringiensis by protoplast transformation and plasmid transfer.

The Staphylococcus aureus plasmid pC194 which codes for resistance to chloramphenicol was introduced into six Bacillus thuringiensis strains representing five varieties by protoplast transformation. Six other varieties could not be transformed. pC194 could be identified in transformed strains as autonomous plasmid. The transformed clones contained in addition a new extrachromosomal element of somewhat lower electrophoretic mobility hybridizing with pC194, and pC194 in multimeric forms. pC194 was also transferred from one B. thuringiensis variety to another and from Bacillus thuringiensis to Bacillus subtilis and vice versa by a conjugation-like process, requiring close cell-to-cell contact.

Bacillus thuringiensis↗
PubMed1983

Specificities of monoclonal antibodies against the activated delta-endotoxin of Bacillus thuringiensis var. thuringiensis.

Eight hybrid cell lines secreting monoclonal antibodies directed against the activated delta-endotoxin of Bacillus thuringiensis var. thuringiensis were grown in BALB/c mice. Ascites fluids were collected, and the antibodies were purified by antigen-affinity chromatography. The specificity of each monoclonal antibody for the toxin and protoxin was established by the indirect enzyme-linked immunosorbent assay. All the antibodies consisted of gamma 1 heavy and kappa light chains. They were reactive with both the native toxin and the protoxin. In contrast to specific goat antiserum, they failed, however, to bind to heat and sodium dodecyl sulfate denatured antigen. These eight cloned cell lines gave rise to five kinds of antibodies distinguished by isoelectric focusing. Competitive antibody binding studies revealed that these five antibodies recognize at least four distinct antigenic determinants of the native toxin and the protoxin. Two of the epitopes are unrelated, whereas three antibodies compete for binding to their antigenic determinants. In the bioassay with larvae of Pieris brassicae, one antibody was found to block the toxin and protoxin activity completely. A second inhibited it partially, whereas the other three antibodies did not affect it at all.

Antibodies, Bacterial↗
PubMed1981

Bacterial mesosomes: method dependent artifacts.

The occurrence of mesosomes was investigated during septum formation of vegetative and sporulating cells of Bacillus cereus. It has been demonstrated that bacterial mesosomes which are considered by numerous microbiologists as an integrated constituent of Gram positive bacteria, are in reality artifacts arising during the preparation for electron microscopy. The conventional fixation methods allowed enough time for the cytoplasmic membrane to react to the changed conditions and to form the typical pocket-like membrane invaginations. With cryofixation followed by freeze-substitution it was shown in ultrathin sections that mesosomes do not occur. The extremely rapid freezing and the substitution of the ice by an organic solvent containing the fixative prevented the formation of membraneous artifacts.

Bacillus cereus↗
PubMed1979

[Blood picture changes in patients hospitalized in an internal medical department].

One quarter, i.e. 810 of 3621 patients admitted to a medical department showed quantitative abnormalities of the blood picture even when leukocytosis is excluded. In contrast, only in 113 cases were hematological diseases the main diagnoses on the hospital charts. 18% of the patients hospitalized for the first time had anemia. On analysis of blood changes according to their causes, 28% were found to be of either iatrogenic or toxic origin, the two causes exhibiting roughly the same frequency. The incidence of iatrogenic and toxic blood changes was equal to that of blood abnormalities due to malignant disease including hemoblastoses. Alcohol and phenacetin were the most frequent exogenous toxins, while anticoagulant, immunosuppressant and ulcerogenic drugs were the most frequent iatrogenic causes of abnormalities.

Alcoholism↗
PubMed1973

Production of -endotoxin by Bacillus thuringiensis as a function of glucose concentrations.

The insect pathogen Bacillus thuringiensis was cultured at different glucose concentrations. Size, protein content, and insecticidal activity of the parasporal inclusions, which are formed during the sporulation process, were measured. Increased glucose concentrations led to bigger crystalline inclusions with a higher content of protein and insecticidal activity. Maximum yields of protein and endotoxin were obtained in a semisynthetic medium that contained glucose concentrations of 6 to 8 g/liter.

Animals↗