Biomedical subjects
J Wagner
Publications and source records attributed to J Wagner.
Invasive Trichosporon cutaneum (beigelii) infection in a patient with relapsed acute myeloid leukemia undergoing bone marrow transplantation.
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[Concepts of the biomechanics of the human spine].
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Ground-state splitting of the 78-meV double acceptor in GaAs.
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[Aeromonas hydrophila as an autochthonous causative agent of infectious enteritis in Germany].
Aeromonas hydrophila was identified by culture technique in diarrhoeal stools and ascites in a patient of 57 years of age who suffered from known alcoholic cirrhosis and additional acute gastroenteritis. No other pathogens that would produce acute diarrhoea were found. The isolated Aeromonas hydrophila strain was characterised by the pathogenic properties known to date as pertaining to this species (formation of haemolysin and enterotoxins). Hence it is evident that Aeromonas hydrophila occurs in Germany also as an autochthonous pathogen of acute infectious enteritis.
Separation of the enantiomers of substituted putrescine and cadaverine analogues by gas chromatography on chiral and achiral stationary phases.
Capillary gas chromatography (GC) on chiral stationary phases, i.e., Chirasil-Val [L-valine-tert.-(R)-alpha-butylamide] and XE-60-S-valine-(R)-alpha-phenylethylamide, has been applied to the resolution of various substituted analogues of putrescine as their N,N'-perfluoroacyl derivatives. The influence of the nature of the substituent on the retention behaviour and on the resolution of the enantiomers was studied. The results are discussed in terms of volatility and interaction with the chiral stationary phase. The 1,4-disubstituted putrescine analogues with two chiral centres were also clearly resolved into their corresponding stereoisomers. When the chain length between the two amino groups was increased, no clear resolution was obtained of the monosubstituted cadaverine analogues as their N,N'-perfluoroacyl derivatives. However, resolution was obtained after derivatization of the cadaverine analogues with (-)-alpha-methoxy-alpha-trifluoromethylphenylacetyl chloride, followed by GC analysis on an achiral phase.
Chiral separation of enantiomers of substituted alpha- and beta-alanine and gamma-aminobutyric acid analogues by gas chromatography and high-performance liquid chromatography.
Gas chromatography (GC) with a chiral stationary phase, Chirasil-Val, has been used for separation of the enantiomers of several analogues of alpha- and beta-alanine as their N-trifluoroacetyl isopropyl esters. The same chiral phase GC procedure has been applied to the enantiomeric separation of various substituted gamma-aminobutyric acid analogues (GABA). Reversed-phase high-performance liquid chromatography (HPLC) with the chiral copper-L-proline complex allowed a clear resolution of all the alpha-amino acids in their underivatized forms. It yielded somewhat smaller separation coefficients for the substituted beta-alanines and no resolution for the GABA analogues. The influence of the nature of the amino acid, alpha, beta or gamma, and the effects of the different substituents on the separation coefficients obtained by GC and HPLC are discussed.
Monitoring heart and respiratory activity by impedance change using neck electrodes.
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Resolution of the enantiomers of various alpha-substituted ornithine and lysine analogs by high-performance liquid chromatography with chiral eluant and by gas chromatography on Chirasil-Val.
A reversed-phase high-performance liquid chromatography method, with L-proline and copper as chiral mobile phase, is described for the enantiomeric resolution of various alpha-substituted ornithine and lysine analogs. Although ornithine gives no separation with the chiral eluant used, excellent resolutions are obtained for various alpha-alkyl-, alpha-halogenomethyl-, alpha-vinyl-, and alpha-ethynyl-substituted ornithines. Similar separations are also observed for the dehydroornithine and lysine analogs. Gas chromatography on a chiral stationary phase, Chirasil-Val, allows the resolution of the ornithine and lysine analogs after derivatization into the monofluoroacyl derivatives of their corresponding lactams. No resolution or only a poor resolution is obtained by GC on Chirasil-Val for the dehydroornithine analogs as their di-N-perfluoroacyl alkyl esters. The chiral eluant HPLC procedure is easily scaled up for the semipreparative resolution of several ornithine analogs, i.e., alpha-fluoromethylornithine, alpha-difluoromethylornithine, alpha-chlorofluoromethylornithine, and alpha-fluoromethyldehydroornithine, which are known as potent ornithine decarboxylase inhibitors in vitro and in vivo.
Antigenic comparison of the polypeptides of foot-and-mouth disease virus serotypes and other picornaviruses.
The cross-reactivity of proteins coded for by the seven serotypes of foot-and-mouth disease virus (FMDV) was assessed by reaction of infected cell lysates with polyclonal and monospecific antisera against the structural and nonstructural proteins of FMDV type A12 strain 119ab. It was shown that the homologous polypeptides from most serotypes are antigenically related. The least cross-reactivity occurred between VP1, VP3, and the protease (3C) of type A12 and South African Territories types 1 and 3. There was also a reduced degree of reactivity of A12 VP1 serum with VP1 from some A subtypes and the other serotypes. Comparison of FMDV proteins with polypeptides from other picornaviruses by a radioimmune binding assay revealed a low level of reactivity of antisera against some A12 polypeptides with encephalomyocarditis virus (EMCV) infected cell lysates but no reactivity with bovine enterovirus type 1 and swine vesicular disease virus infected cells. The same EMCV proteins were immunoprecipitated by the various reactive A12 antisera, but the reaction was abolished if the lysate from EMCV infected cells was denatured prior to immunoprecipitation.
Epidural spinal cord compression from metastatic tumor.
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Anaesthetic properties of pregnanolone emulsion. A comparison with alphaxolone/alphadolone, propofol, thiopentone and midazolam in a rat model.
The anaesthetic properties of pregnanolone emulsion, a new steroid preparation for intravenous administration, were evaluated in rats and compared to those of Althesin, propofol, thiopentone and midazolam. The therapeutic index was found to be 50% higher than that of Althesin and 6-8 times higher than those of propofol, thiopentone and midazolam. Induction with pregnanolone emulsion was reliable and fast, with only minor excitatory side effects, although induction time was longer compared to Althesin, propofol and thiopentone. Movement of unstimulated rats during sleep was similar to that seen with Althesin but movement on painful stimulation was less than with propofol and thiopentone. Recovery was rapid and smooth, and the proportion of sleeping time to recovery time was higher than found for the other four anaesthetics. No cumulative effects were seen on repeated administration and there were no venous sequelae. The results indicate that pregnanolone emulsion may provide a short-acting, less cumulative and less toxic alternative to existing intravenous anaesthetic agents.
Prospective randomized controlled study of ciprofloxacin versus imipenem-cilastatin in severe clinical infections.
In a randomized prospective study, 66 patients with serious bacterial infections--mainly lower respiratory tract infections--were treated with either imipenem plus cilastatin (32 patients) or ciprofloxacin (34 patients); 30 patients in each group were evaluable for efficacy. Substantial underlying disease was present in most of the patients; pathogens isolated prior to treatment (77 isolates) consisted mainly of members of the family Enterobacteriaceae, Pseudomonas aeruginosa, Staphylococcus aureus, Haemophilus influenzae, and streptococci. Of the etiologic bacteria, 67% were eradicated by ciprofloxacin treatment and 79% by imipenem therapy; however, two patients (6.7%) failed in the ciprofloxacin group, and six patients (20%) did not respond to imipenem treatment (P = 0.25). All patients with therapeutic failures suffered from severe fatal underlying diseases, which had substantial impact on the outcome of treatment. Therapeutic drug monitoring in the ciprofloxacin patients revealed higher concentrations in serum at days 4 and 8 in comparison with day 1 of treatment, indicating that steady-state conditions were reached between days 1 and 4. The total number of side effects was relatively high--eight imipenem patients (25%) and six ciprofloxacin patients (18%) had reactions. Treatment had to be discontinued due to adverse reactions for three ciprofloxacin patients and two imipenem patients. Major side effects in both groups were gastrointestinal and central nervous system-related symptoms. In terms of clinical and bacteriological efficacy and safety, there was no statistical difference between the two groups, and both groups gave good to excellent results for bacterial infections that were difficult to treat.
Induction of microsomal enzymes in rat liver by oxcarbazepine, 10,11-dihydro-10-hydroxy-carbamazepine and carbamazepine.
1. The effects of the new anti-epileptic drug, oxcarbazepine, its major metabolite in man, 10,11-dihydro-10-hydroxy-carbamazepine, and carbamazepine, on hepatic microsomal enzyme activities have been studied in rats after repeated administration of equimolar doses. 2. All three compounds caused a qualitatively similar induction of the mono-oxygenase system, the greatest increase being observed in the activity of 4-nitroanisole O-demethylase. Oxcarbazepine is as potent as carbamazepine, while 10,11-dihydro-10-hydroxy-carbamazepine is a weak inducer. 3. The observation that oxcarbazepine is a potent inducer in rats but not in man is explained by the species differences in its metabolism.
[An information system for hospital hygiene. III. Exploratory data analysis of the dynamic aspects in the pathogen spectra of patient specimens from two intensive care units at a Berlin university hospital].
For the 18-months period ending June 1986 the computerised database of the institutes of medical microbiology and of hygiene at Berlin Free University showed about 12,200 specimens from 1,236 intensive care patients. In addition to a traditional tabulation of pathogens by site (urine, wound, bronchial secretion and blood) and service (multidisciplinary post-operative, 4,628 isolates and internal medicine, 1,813 isolates) resulting in a time aggregated assessment of the patients at both intensive care units (ICU) the same data were analysed to detect dynamic variations using 3 different approaches: (1) Medians of the sampling time span (STS) from first specimen of the same patient to follow-up specimens were analysed for 8 pathogens. In specimens from the bronchial tract S. aureus, Klebsiella spp., enterococci and P. aeruginosa showed the same sequence of STS-medians at both ICUs. (2) Dynamic modelling of sequential batches of 100 specimens from the bronchial tract using 3RSSH smoothing showed only poor variation in the proportion of E. coli and enterococci, but demonstrated substantial variation in S. aureus and P. aeruginosa. (3) The negative exponential model was used to fit frequency distributions of STS data. The model suggests a STS half life of 8 days before the first P. aeruginosa is reported from specimens of the bronchial tract of patients mostly with respirators. Periodical reporting of these indicators provides quantitative reference and enables the clinician to better relate individual information from his patients to the epidemiological outcome of his unit.
Calcium/calmodulin activation of gizzard skinned fibers at low levels of myosin phosphorylation.
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A sensitive high-performance liquid chromatographic procedure with fluorometric detection for the analysis of decarboxylated S-adenosylmethionine and analogs in urine samples.
A highly sensitive HPLC method for the determination of decarboxylated S-adenosylmethionine (dc-SAM) by fluorometric detection was developed. The reaction of dc-SAM and its analogs with chloroacetaldehyde leads to the corresponding 1,N6-etheno derivatives. These highly fluorescent derivatives were fully characterized through their proton nuclear magnetic resonance spectra and/or mass spectra. This derivatization procedure has been applied to the analysis of dc-SAM in rat and human urine. After a simple cation exchange column prepurification, the urine extracts were derivatized with chloroacetaldehyde and analyzed by reversed-phase HPLC with fluorometric detection. The method allowed the determination of subpicomole amounts of dc-SAM and was shown to be highly reproducible with the use of decarboxylated S-adenosylethionine as internal standard. The application of the method to the analysis of urine of rats treated with MDL 72175, a potent ornithine decarboxylase inhibitor, showed that the dc-SAM levels increased in a dose-related fashion.
Polyamine depletion increases cellular ribonucleotide levels.
Depletion of the putrescine and spermidine content of Ehrlich ascites tumor cells by alpha-difluoromethylornithine (DFMO) treatment results in at least a 1 500-fold increase in the decarboxylated S-adenosylmethionine (deSAM) content. The accumulation of this adenine nucleoside occurs because of the absence of putrescine and spermidine to act as aminopropyl group acceptors in the spermidine and spermine synthase reactions and because of an increase in S-adenosylmethionine decarboxylase activity. The fact that the synthesis of deSAM continues in DFMO-treated cells makes the pathway an adenine trap. This prompted a study of the adenine nucleotide pools. High-performance liquid chromatographic analysis showed that the total adenine nucleotide pool increased, rather than decreased, as a result of DFMO treatment; the major contributors to the increase being ATP and ADP, which increased 2.6 and 1.9 times, respectively. The cellular content of other ribonucleotides increased as well, particularly that of UTP and CTP. When putrescine was added together with DFMO, the increases in cellular ribonucleotide contents were prevented, showing that they were indeed caused by polyamine depletion.