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Biomedical subjects

M Contzen

Publications and source records attributed to M Contzen.

9 recordsLinked to original sources
PubMed2006

[Comparison of two different laryngeal mask models for airway management in patients with immobilization of the cervical spine].

BACKGROUND: Reduced cervical spine mobility can impair laryngoscopy and tracheal intubation. Supraglottic airway devices can be important alternatives for oxygenation under these circumstances. The Ambu laryngeal mask (ALM) and the LMA-Classic (LMA) are compared in patients with immobilization of the cervical spine. METHODS: In 60 patients scheduled for elective ambulatory interventions, ALM or LMA were inserted after cervical immobilization with an extrication collar and assessment of laryngoscopic view. Insertion time (removal of facemask until first tidal volume), number of insertion attempts, airway leak pressure (cuff pressure 60 cm H(2)O), intraoperative complications and postoperative complaints were assessed. RESULTS: Demographical data, insertion attempts, insertion time (ALM 15.6+/-4.4 s, LMA 15.5+/-4.9 s) and airway leak pressure (ALM 25.6+/-5.2 cm H(2)O, LMA 26.5+/-6.5 cm H(2)O) were comparable. Traces of blood were found in 6 LMAs and 3 ALMs after removal, mild trouble with swallowing (visual analogue scale, VAS 2-4) in the recovery room and after 24 h were complaints by 1 ALM and 2 LMA patients. CONCLUSIONS: LMA-Classic and Ambu laryngeal masks are suitable for rapid and reliable airway management in patients with cervical immobilization.

Adolescent↗
PubMed2001

Cloning of the genes for a 4-sulphocatechol-oxidizing protocatechuate 3,4-dioxygenase from Hydrogenophaga intermedia S1 and identification of the amino acid residues responsible for the ability to convert 4-sulphocatechol.

The genes for a protocatechuate 3,4-dioxygenase (P34O-II) with the ability to oxidize 4-sulphocatechol were cloned from the 4-aminobenzenesulphonate(sulphanilate)-degrading bacterium Hydrogenophaga intermedia strain S1 (DSMZ 5680). Sequence comparisons of the deduced amino acid sequences of both subunits of the P34O-II from H. intermedia S1 (PcaH-II and PcaG-II) with those of another P34O-II, previously obtained from Agrobacterium radiobacter S2, and the corresponding sequences from the protocatechuate 3,4-dioxygenases from other bacterial genera demonstrated that seven amino acid residues, which were conserved in all previously known P34Os (P34O-Is), were different in both P34O-IIs. According to previously published structural data for the P34O of Pseudomonas putida only two of these amino acid residues were located near the catalytical centre. The respective amino acid residues were mutated in the P34O-I from A. radiobacter S2 by site-specific mutagenesis, and it was found that a single amino acid exchange enabled the protocatechuate converting P34O also to oxidize 4-sulphocatechol.

3,4-Dihydroxyphenylacetic Acid↗
PubMed2000

Hydrogenophaga intermedia sp. nov., a 4-aminobenzenesulfonate degrading organism.

The taxonomic status of a gram-negative, oxidase positive rod (strain S1) able to degrade 4-aminobenzenesulfonate was studied using a polyphasic approach. Chemotaxonomic investigations of quinones and polar lipids established the allocation of this strain to the beta-subclass of the Proteobacteria and revealed similarities to Hydrogenophaga palleronii. 16S rRNA sequence comparisons demonstrated that this strain clusters phylogenetically with H. palleronii and H. taeniospiralis, but clearly represents a new species. The fatty acid patterns and substrate utilization profile displayed similarity to the characteristics of the four validly published species of Hydrogenophaga, although clear differentiating characters were also observed. No close similarities between the type strains of H. palleronii and H. taeniospiralis were detected in hybridization experiments with the genomic DNAs. On basis of these results, the new species Hydrogenophaga intermedia sp. nov. is proposed, with the type strain S1T (= DSM 5680).

Bacterial Typing Techniques↗
PubMed2000

Characterization of the genes for two protocatechuate 3, 4-dioxygenases from the 4-sulfocatechol-degrading bacterium Agrobacterium radiobacter strain S2.

The genes for two different protocatechuate 3,4-dioxygenases (P34Os) were cloned from the 4-sulfocatechol-degrading bacterium Agrobacterium radiobacter strain S2 (DSMZ 5681). The pcaH1G1 genes encoded a P34O (P34O-I) which oxidized protocatechuate but not 4-sulfocatechol. These genes were part of a protocatechuate-degradative operon which strongly resembled the isofunctional operon from the protocatechuate-degrading strain Agrobacterium tumefaciens A348 described previously by D. Parke (FEMS Microbiol. Lett. 146:3-12, 1997). The second P34O (P34O-II), encoded by the pcaH2G2 genes, was functionally expressed and shown to convert protocatechuate and 4-sulfocatechol. A comparison of the deduced amino acid sequences of PcaH-I and PcaH-II, and of PcaG-I and PcaG-II, with each other and with the corresponding sequences from the P34Os, from other bacterial genera suggested that the genes for the P34O-II were obtained by strain S2 by lateral gene transfer. The genes encoding the P34O-II were found in a putative operon together with two genes which, according to sequence alignments, encoded transport proteins. Further downstream from this putative operon, two open reading frames which code for a putative regulator protein of the IclR family and a putative 3-carboxymuconate cycloisomerase were identified.

Amino Acid Sequence↗
PubMed1999

Catalytic properties of the 3-chlorocatechol-oxidizing 2, 3-dihydroxybiphenyl 1,2-dioxygenase from Sphingomonas sp. strain BN6.

The 2,3-dihydroxybiphenyl dioxygenase from Sphingomonas sp. strain BN6 (BphC1-BN6) differs from most other extradiol dioxygenases by its ability to oxidize 3-chlorocatechol to 3-chloro-2-hydroxymuconic semialdehyde by a distal cleavage mechanism. The turnover of different substrates and the effects of various inhibitors on BphC1-BN6 were compared with those of another 2,3-dihydroxybiphenyl dioxygenase from the same strain (BphC2-BN6) as well as with those of the archetypical catechol 2,3-dioxygenase (C23O-mt2) encoded by the TOL plasmid. Cell extracts containing C23O-mt2 or BphC2-BN6 converted the relevant substrates with an almost constant rate for at least 10 min, whereas BphC1-BN6 was inactivated significantly within the first minutes during the turnover of all substrates tested. Furthermore, BphC1-BN6 was much more sensitive than the other two enzymes to inactivation by the Fe(II) ion-chelating compound o-phenanthroline. The reason for inactivation of BphC1-BN6 appeared to be the loss of the weakly bound ferrous ion, which is the cofactor in the catalytic center. A mutant enzyme of BphC1-BN6 constructed by site-directed mutagenesis showed a higher stability to inactivation by o-phenanthroline and an increased catalytic efficiency for the conversion of 2,3-dihydroxybiphenyl and 3-methylcatechol but was still inactivated during substrate oxidation.

Catalytic Domain↗
PubMed1998

Isolation of a bacterial strain with the ability to utilize the sulfonated azo compound 4-carboxy-4'-sulfoazobenzene as the sole source of carbon and energy.

A bacterial strain (strain S5) which grows aerobically with the sulfonated azo compound 4-carboxy-4'-sulfoazobenzene as the sole source of carbon and energy was isolated. This strain was obtained by continuous adaptation of "Hydrogenophaga palleronii" S1, which has the ability to grow aerobically with 4-aminobenzenesulfonate. Strain S5 probably cleaves 4-carboxy-4'-sulfoazobenzene reductively under aerobic conditions to 4-aminobenzoate and 4-aminobenzene-sulfonate, which are mineralized by previously established degradation pathways.

Azo Compounds↗
PubMed1996

Degradation of benzene 1,3-disulfonate by a mixed bacterial culture.

A benzene 1,3-disulfonate degrading mixed bacterial culture was isolated from the River Elbe downstream of Hamburg. The mixed culture was composed of five different bacterial strains. None of these strains grew in axenic culture with benzene 1,3-disulfonate as sole source of carbon and energy. In the presence of 4-nitrocatechol, resting cells of the mixed culture converted benzene 1,3-disulfonate to catechol 4-sulfonate. Experiments with cell-free extracts demonstrated that catechol 4-sulfonate was further metabolized via 3-sulfomuconate and 4-carboxymethyl-4-sulfobut-2-en-4-olide.

Benzenesulfonates↗