Biomedical subjects

H Büchner

Publications and source records attributed to H Büchner.

11 recordsLinked to original sources

PubMed1993

Molecular cloning and functional characterization of V2 [8-lysine] vasopressin and oxytocin receptors from a pig kidney cell line.

[Arg8]vasopressin and oxytocin are the two main members of the neurohypophysial hormone family found to be present in nearly all mammals. [Lys8]vasopressin ([Lys8]VP) has been identified as the antidiuretic hormone in pig and some marsupial families. The porcine-derived kidney epithelial cell line, LLC-PK1, expresses both [Lys8]VP receptors coupled to the activation of adenylate cyclase (V2 receptors) and oxytocin receptors. Here we report the molecular cloning of the V2 [Lys8]VP receptor and the oxytocin receptor from LLC-PK1 cells. The cloned V2 [Lys8]VP receptor differs from human and rat V2 [Arg8] receptors mainly in its N-terminal region, in residues located in the extracellular loops and in intracellular phosphorylation sites. When expressed in COS7 cells, the V2 [Lys8]VP receptor exhibits the relative order of ligand affinity [Lys8]VP = [Arg8]VP >> 1-deamino[D-Arg8]VP > or = oxytocin and adenylate-cyclase stimulation, expected for the porcine V2 [Lys8]VP receptor but different from V2 [Arg8]VP receptors. Adenylate-cyclase activation by [Lys8]VP was inhibited in COS7 cells by a V2 antagonist. The cloned oxytocin receptor exhibits in COS7 cells a ligand specificity typical of mammalian oxytocin receptors. mRNA-distribution analysis revealed a single 5.5-kb transcript in the uterus from pregnant guinea pig.

Amino Acid Sequence↗

PubMed1992

Molecular cloning of a new bombesin receptor subtype expressed in uterus during pregnancy.

The homology screening approach has been used to clone a new member of the guanine-nucleotide-binding-protein-coupled receptor superfamily from guinea pig uterus. The cloned cDNA encodes a 399-amino-acid protein and shows the highest amino acid similarity to members of the bombesin receptor family; 52% and 47% similarity to the gastrin-releasing-peptide (GRP) receptor and the neuromedin-B receptor, respectively. Binding experiments with the stably transfected LLC-PK1 cell line expressing the new receptor protein confirmed the bombesin-like nature of the cloned receptor. The relative order of ligand affinity, GRP = neuromedin C much greater than neuromedin B, suggests that the cloned cDNA represents the GRP subtype rather than the neuromedin-B subtype of bombesin receptors. Northern-blot analysis of mRNA species from several guinea-pig tissues showed that the mRNA for the new bombesin receptor subtype is expressed mainly in uteri of pregnant animals.

Amino Acid Sequence↗

PubMed1987

[Variation in nocturnal blood pressure behavior in stage III (WHO) hypertension--a case report].

In some cases of hypertensive men the authors obtained 24-hour blood pressure profiles by easy non-invasive technique (Mercury manometer) and under the usual atmosphere and activities of a hospital. The control Group, 32 normotensive men, showed a normal circadian blood pressure variability with systolic acrophases at 10.00 h and 16.00 h and a bathyphase around 3.00 h. The diastolic blood pressure had a smaller variability. One patient with essential hypertension stage II (WHO), case 1, kept the normal day-night rhythm. By case 2, a man with essential hypertension stage III (WHO), the authors refer to the possibility of considerable differences of blood pressure behaviour during the night in cases of severe hypertension in contrary to normal blood pressure variability. After a supplementary fourth medication this patient showed a significant decrease of blood pressure during the night. Nevertheless he kept his acrophase at night. The recording of day-night profiles of blood pressure seems to be useful in relation to the judgement of classification of severity, of the mode of anti-hypertensive medication and of the success in therapy.

Antihypertensive Agents↗

PubMed1984

[Quality assurance in roentgen tomography. Initial report on a sectional phantom assembly for all parameters].

A tomographie phantom developed by a new principle is presented for quality assurance and testing of the installation as well as for postgraduate teaching and lectures. It is composed likely to a set for construction-games consisting of fitting cubes and parts. The phantom-cubes include some test objects not yet published. The concerning parameters and conditions of tomographic technique are thus able to be demonstrated separately, in a selected combination or all together by one exposure. All parameters are to be read off the tomogram without calculations or further operations. Some examples are selected out of the group of the parameter- and teaching-cubes.

Humans↗

PubMed1969