Herstellung radioaktiv markierter äthylen/propylen copolymerer. Berechnung der primärstruktur aus kinetischen daten

A synthesis method for ethylene/propylene copolymers labelled with tritium at the α-methyl groups was worked out. The activity is sufficient for a detection of the pyrolysis products in a Geiger counter. The sequence distribution of copolymers prepared with Ziegler-Natta catalysts was calculated from kinetic measurements. Studies on mechanisms of thermal decomposition in such copolymers as well as on the application of pyrolysis to determine the distribution of chemical sequences shall be discussed in further reports.     

Die präoperative Verminderung der Darmfora unter Verwendung von Achromycin,Neomycin und Intestin-Euvernil

Ohne Zusammenfassung     

Triggering effect of physical and mental stress on spontaneous ventricular tachyarrhythmias in patients with implantable cardioverter-defibrillators

BACKGROUND: Physical and mental stress as well as sexual activity are potential triggering factors of acute coronary events and sudden cardiac death. HYPOTHESIS: These factors may also trigger recurrence of spontaneous ventricular tachyarrhythmias in patients with implantable cardioverter-defibrillators (ICDs). METHODS: We performed a case-crossover study in 43 consecutive patients with 95 symptomatic, ICD-documented tachyarrhythmic events and calculated the relative risk of tachyarrhythmia recurrence during physical and mental stress. Physical and mental activity was graded on a 4-step intensity scale, and stress was defined as physical exertion or mental stress with an intensity grade > or = II during or up to 1 h before arrhythmia recurrence. Relative risk was determined taking into account the habitual weekly stress frequency of each patient. RESULTS: Physical stress was present in 26% (n = 25), mental stress in 24% (n = 23), and sexual activity in 2% (n = 2) of analyzed events. The weekly habitual stress frequency was 8 +/- 8 (median 7) for physical stress, 6 +/- 6 (median 4) for mental stress, and 0.5 +/- 0.5 (median 0.25) for sexual activity. Thus, relative risk of arrhythmia recurrence during the presence of stress was 7.5 for physical activity (95% confidence interval [CI] 5.2-11.1), 9.5 (CI 6.3-14.5) for mental activity, and 7.5 (CI 2.3-24.8) for sexual activity. CONCLUSIONS: Physical and mental stress as well as sexual activity are factors that significantly increase relative risk of spontaneous recurrence of sustained ventricular tachyarrhythmias in patients with ICDs. Consideration of this stress-related relative risk increase may contribute to avoidance of harmful shock delivery in ICD recipients.     

Pityriacitrin -- an ultraviolet-absorbing indole alkaloid from the yeast Malassezia furfur

As the main nitrogen source in Malassezia furfur, tryptophan induces the formation of fluorochromes and pigments, which make the yeast less sensitive to UV light. To detect a chemical UV filter, M. furfur (CBS 1878) was incubated at 30 degrees C for 14 days on a pigment-inducing medium and agar extracts were purified by column chromatography, preparative TLC and HPLC. Structural analysis of the pure metabolites was performed by mass spectroscopy and NMR. A yellow compound eluting from the column with 64% acetonitrile was found to be a potential UV filter because of its broad UV absorption (lambda(max) 389, 315, 289, 212 nm). It was an indole derivative (C(20)H(13)N(3)O; pityriacitrin) which had recently been shown to be a potent UV filter in bacteria. Its UV protective properties were confirmed in a yeast model and also in humans. Pityriasis versicolor induced by Malassezia yeasts is characterized by depigmented skin areas showing reduced melanin synthesis but no increased UV sensitivity. This UV protection might be explained by the presence of pityriacitrin which is produced by M. furfur.     

Defining the glycophenotype of squamous epithelia using plant and mammalian lectins. Differentiation-dependent expression of alpha2,6- and alpha2,3-linked N-acetylneuraminic acid in squamous epithelia and carcinomas,and its differential effect on binding of the endogenous lectins galectins-1 and -3

A thorough characterization of the properties of squamous epithelial cells is necessary in order to improve our understanding of the functional aspects of normal development and malignant aberrations. Up to now, studies have focused almost exclusively on monitoring distinct protein markers. With our growing awareness of the coding function of glycan chains of cellular glycoconjugates and their interaction with receptors (lectins) in situ, defining the glycophenotype of these cells has become an important issue. Whereas the commonly applied plant lectins are tools used to map the presence and localization of biochemically defined saccharide epitopes, the introduction of endogenous (mammalian) lectins to this analysis enables us to take the step from monitoring the presence of glycan to understanding the functional implications by revealing ligand properties of the detected epitope for tissue lectin. Thus, in this study we investigated a distinct aspect of glycosylation using plant and mammalian lectins, i.e. the linkage type of sialylation. We first mapped the expression profile of the type of sialylation (alpha2,3- or alpha2,6-linked) by plant lectins. Based on the hypothesis that this factor regulates accessibility of ligands for endogenous lectins we introduced two labeled galectins to this study. Galectin-3 (but not galectin-1) binding was related to cell differentiation in normal adult and developing epithelia, cultured epidermal cells, and carcinomas derived from these epithelia. The presented data suggest that alpha2,6-linked N-acetyl-D-neuraminic acid moieties could serve to mask galectin-3-reactive glycoepitopes. As a consequence, monitoring of the linkage type of sialic acid in glycans by plant lectins therefore has implications for the extent of glycan reactivity with endogenous lectins, pointing to a potential function of changes in sialylation type beyond these cell and lectin systems.     

Antibody formation during intravenous and intramuscular therapy with Erwinia asparaginase

BACKGROUND: Determination of the frequency of antibody formation during first and second exposure to Erwinia asparaginase after i.v. and i.m. administration. PROCEDURE: Thirty-nine children with newly diagnosed acute lymphoblastic leukemia (ALL) were included in this prospective study. Antibodies were determined (ELISA method) in plasma from these patients on specific days during and after therapy with 30,000 IU/m(2) i.v. or i.m. every day for ten days during the induction phase (first exposure). For 19 children, antibodies were measured in plasma during and after the re-induction phase (second exposure) following treatment with 30,000 IU/m(2) i.v. or i.m. twice a week for two weeks (Mondays and Thursdays). On the same days of therapy, enzyme activity (spectrophotometric method) and the concentration of asparagine (HPLC) was determined. RESULTS: During the first exposure, none of the patients developed anti-Erwinia asparaginase antibodies. During the second exposure, one patient (1 of 8 patients) treated intravenously developed antibodies, which were associated with disappearance of enzyme activity and reappearance of asparagine. Three of eleven patients developed antibodies of pharmacokinetic importance after i.m. therapy. None of the children had any clinical symptoms of hypersensitivity. CONCLUSIONS: The formation of antibodies and subsequently altered pharmacokinetics of Erwinia asparaginase seemed to be of importance only during a second period of asparaginase therapy.