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G Frey

Publications and source records attributed to G Frey.

At least 19 recordsLinked to original sources
PubMed1992

Transcription in vitro and in vivo of the 7S RNA gene associated with the ribosomal RNA operon in the hyperthermophilic archaeon Methanothermus fervidus.

The gene encoding the archaeal 7S RNA in the hyperthermophile Methanothermus fervidus is linked to a tRNA(Ser) and rRNA operon in the arrangement 5'-7S RNA-14nt-tRNA(Ser)-196nt-16S rRNA and the promoter directing transcription of this 7S RNA gene has now been identified. Initiation of transcription of the 7S RNA gene has been shown to occur both in vivo in M. fervidus and in vitro, using a Methanococcus thermolithotrophicus derived cell-free transcription system, at the first G residue within the initiator sequence ATGG, located 6 bp upstream of the 5' end of the 7S RNA coding region. Cotranscription of the 7S RNA and tRNA(Ser) has been demonstrated in vitro.

Base Sequence↗
PubMed1992

Transcription in vivo and in vitro of the histone-encoding gene hmfB from the hyperthermophilic archaeon Methanothermus fervidus.

Immediately upstream of the hmfB gene, in a DNA fragment cloned from Methanothermus fervidus, are two identical tandemly repeated copies of a 73-bp sequence that contain the sequence 5'TTTATATA, which conforms precisely to the consensus TATA box element proposed for methanogen promoters. By using this duplicated region as the template DNA and a cell-free transcription system derived from Methanococcus thermolithotrophicus, transcription in vitro was found to initiate at two identical sites 73 bp apart, each 25 bp downstream from a TATA box, thus providing strong evidence for the functional conservation of this transcriptional signal in two phylogenetically very diverse methanogens. Transcription of the hmfB gene in vivo in M. fervidus was found to occur at only one of these sites, and consistent with this observation, recloning and sequencing of this intergenic region after its amplification by the polymerase chain reaction demonstrated that the genome of M. fervidus contains only one copy of the 73-bp sequence upstream of the hmfB gene. Since the second copy of the 73-bp sequence, presumably generated artifactually during the original hmfB cloning, functioned equally well as a promoter in the M. thermolithotrophicus transcription system, all information needed by the heterologous RNA polymerase to initiate transcription accurately in vitro must be present within this sequence. The hmfB gene encodes HMf-2, one of the two subunits of HMf, an abundant DNA binding protein in M. fervidus which binds to DNA molecules in vitro, forming nucleosomelike structures. Cell-free transcription was inhibited by adding HMf or eucaryotic core histones at protein-to-DNA mass ratios of 0.3:1 and 1:1, respectively, whereas the archael histonelike protein HTa from Thermoplasma acidophilum inhibited transcription in vitro only at much higher protein-to-DNA mass ratios and the bacterial histonelike protein HU from Escherichia coli had no detectable effect on transcription.

Archaeal Proteins↗
PubMed1992

[Bilateral Gradenigo syndrome--on the value of an integrated therapy concept including hyperbaric oxygenation and chronic destructive inflammation of the skull base].

The case of a 30-year-old female with bilateral Gradenigo's syndrome is presented in order to detail commonly applied therapy. In particular, the importance of a comprehensive therapeutic approach is emphasized that includes such adjuvant therapeutic options as hyperbaric oxygenation and the administration of specific immunoglobulins. Indications, therapeutic benefits and limitations of treatment modalities are discussed in relationship to current concepts of therapy.

Adult↗
PubMed1991

Control regions of an archaeal gene. A TATA box and an initiator element promote cell-free transcription of the tRNA(Val) gene of Methanococcus vannielii.

To identify the DNA sequences required for initiation of transcription in archaea, the 5'-flanking region of the tRNA(Val) gene of Methanococcus vannielii was modified by deletions, restructuring and site-directed mutagenesis, and the tRNA encoding sequence was replaced by a fortuitous Escherichia coli sequence. The effects of these mutations on promoter function were tested in an homologous cell-free transcription system. The DNA region from position -35 to +9 relative to the transcription start site was sufficient for maximal initiation of cell-free transcription. Removal of the DNA region between -35 and -30 reduced initiation by a factor of 2. Deletions extending to position -24 almost completely abolished specific transcription. Analysis of 16 site-specific mutations in the region from -33 to +2 provided evidence that a conserved A + T-rich sequence (TATA box), centered at -25, is essential for initiation of transcription. Single point mutations in six positions of the TATA box reduced initiation of transcription from 0.2 to 0.01 of wild-type levels. A second conserved motif at the transcription start site (consensus ATGC) could be replaced by some sequences containing a pyrimidine-purine dinucleotide but appeared necessary for a maximal rate of gene transcription. Mutations altering the spacing between the two conserved elements demonstrated that initiation occurs at a strictly defined distance of 22 to 27 base-pairs downstream from the TATA box. Our results support the conclusion that the TATA box is the major DNA region mediating promoter recognition, influencing the efficiency of transcription and specifying the site of transcription initiation. This Methanococcus promoter element closely resembles in structure and function the TATA box of promoters of eukaryotic protein-encoding genes transcribed by RNA polymerase II.

Base Sequence↗
PubMed1991

[Neither propranolol nor the vasodilating beta-blocker carvedilol have a direct effect on coronary resistance vessels].

Seventeen patients with coronary heart disease were included in a double-blind randomized study. They received either 5 mg of carvedilol or 6 mg of propranolol intravenously. Heart rate, aortic pressure, mean coronary sinus pressure and coronary flow (thermodilution) were measured, and coronary resistance and rate-pressure product were calculated before and 15 min after the infusion, which lasted 10 min. Carvedilol lowered significantly (p less than 0.05) heart rate (mean 76 to 69/min), aortic pressure (mean 153/80 to 135/72 mm Hg), rate-pressure product (mean 117 to 93 mm Hg/min) and coronary flow (mean 114 to 94 ml/min). Coronary resistance and coronary flow related to rate-pressure product showed no significant change after carvedilol. Propranolol lowered heart rate (mean 76 to 64/min; p less than 0.05) and rate-pressure product (mean 109 to 96 mm Hg/min; ns). Aortic pressure, coronary flow, coronary resistance, and coronary flow related to rate-pressure product showed no significant change after propranolol. Thus, carvedilol lowered rate-pressure product more markedly than propranolol on account of its acute blood-pressure lowering effect. Neither drug seems to have a direct influence on coronary resistance vessels.

Adrenergic beta-Antagonists↗
PubMed1990

[Danger in cave diving].

A diving accident fatal for two divers, that occurred in the Blautopf-cave near Ulm, FRG, is reported. The circumstances fundamental in precipitating the fatal outcome are discussed. As a consequence accident- or life insurance coverage has become one of the prerequisites to obtain the official permit to dive in this cave.

Adult↗
PubMed1990

An archaebacterial cell-free transcription system. The expression of tRNA genes from Methanococcus vannielii is mediated by a transcription factor.

Our understanding of the mechanism of RNA biosynthesis in archaebacteria is limited, due in part to the inability of purified RNA polymerases to transcribe purified genes accurately in vitro. In the present study, we show that cell extracts of Methanococcus vannielii and Methanococcus thermolithotrophicus purified by gradient centrifugation synthesize a distinct transcript from templates harboring a cloned homologous tRNA(Val) and tRNA(Arg) gene. The in vitro transcripts initiate with GTP at the same sites as in Methanococcus cells. About 60% of the sequence of the in vitro RNA products was analyzed by dideoxyterminated primer extension and found to be identical with that of the precursors of tRNA(Val) and tRNA(Arg). This finding indicates that this RNA polymerase fraction both initiates and terminates transcription faithfully in vitro. After purification of a cell-free extract (S-100) of M. thermolithotrophicus by phosphocellulose chromatography, the endogenous RNA polymerase has lost its ability to transcribe the tRNA(Val) gene accurately. The activity directing specific expression of this template was reconstituted by the addition of a protein-fraction devoid of RNA polymerase activity. Thus, a transcription factor appears to be required for accurate cell-free expression of tRNA genes from M. vannielii.

Base Sequence↗
PubMed1990

Influence of carvedilol and propranolol on coronary blood flow.

A total of 17 patients with angiographically proven coronary artery disease and at least one stenosis blocking greater than or equal to 70% of the left anterior descending or circumflex artery were included in a double-blind, randomized study. They received either 5 mg carvedilol or 6 mg propranolol intravenously. Heart rate, aortic pressure, mean coronary sinus pressure and coronary flow (thermodilution) were measured and coronary resistance and the rate-pressure product were calculated before and 25 min after injection. Carvedilol significantly (P less than 0.05) lowered the heart rate (mean, 76 to 69 beats/min), aortic pressure (mean, 153/80-135/72 mm Hg), rate-pressure product (mean, 117-93 mm Hg/min), and coronary flow (mean, 114-94 ml/min). Coronary resistance (mean, 0.97-1.07 mm Hg x min/ml) and coronary flow related to the rate-pressure product (mean, 1.0-1.02 ml/mm Hg) showed no significant change after carvedilol treatment. Propranolol lowered the heart rate (mean, 76-64/min; P less than 0.05) and rate-pressure product (mean, 109-96 mm Hg/min; not significant). Aortic pressure (mean, 145/72-147/74 mm Hg), coronary flow (mean 109-101 ml/min), coronary resistance (mean, 1.1-1.2 mm Hg x min/ml), and coronary flow related to the rate-pressure product (mean, 1.12-1.19 ml/mm Hg) showed no significant change after propranolol administration. Following single application, carvedilol lowered the rate-pressure product more markedly than did propranolol on account of its acute blood-pressure-lowering effect. No differences in the hemodynamic effects of carvedilol and propranolol were found. Neither drug seems to influence the adaption of coronary flow to myocardial oxygen demand.

Adrenergic beta-Antagonists↗
PubMed1979

[Effects of ventilation with defined formaldehyde concentrations on lung function and lung structures. Animal experiments on the noxiousness of formaldehyde residues after disinfection in the aseptor (author's transl)].

Having seen the development of fatal pneumonias in ventilated patients, the cause of which was assumed to be the presence of residual traces of formaldehyde in the air in the respirator Kilian and Haug showed in 1973 initial formaldehyde concentrations up to 0.2 ppm in the ventilatory air of respirators correctly disinfected in the Aseptor. To study the effects of formaldehyde on lung function and lung structures, 23 young pigs were automatically ventilated with defined formaldehyde concentrations during 6 hours. The concentrations used were 0.02 ppm, 0.2 ppm and 2.0 ppm (double of the maximum permissible concentration). We found no differences in lung function, as shown by compliance measurements and arterial blood gas analysis. No radiological differences were in the thorax. Histologically, there were only slight alterations in lung structure in the group ventilated with double the maximum permissible concentration of formaldehyde. We conclude that the disinfection of respirators using formaldehyde in the Aseptor will remain the method of choice.

Animals↗
PubMed1977

[Rescue helicopters in secondary missions].

During the last five years, we have had to fly 560 primary and 1150 secondary missions with the rescue helicopter of the Ulm Rescue Centre. This relationship of approximately 1 : 2 is distinctly different from the numbers obtained in other helicopter bases. The geographical location and structure of the hospitals within range of the Ulm rescue helicopter account for the large proportion of urgent secondary missions. The evaluation of these secondary missions concurs with the ADAC statistics and shows that the quick transport of the emergency doctor to the scene of the emergency, is only one component in the functions of the rescue helicopter. During primary and secondary missions, the ability to transport emergency patients to the nearest qualified hospital by helicopter, which is a mobile intensive care unit, is of equal importance. In the future, rescue helicopters will have to take these requirements into account by providing the necessary equipment and more especially, by providing sufficient space to carry out emergency diagnostic and therapeutic treatment.

Aircraft↗