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Biomedical subjects

D Richter

Publications and source records attributed to D Richter.

At least 307 records · Page 17Linked to original sources
PubMed1987

Purification and characterization of a beta-toxin from the venom of the African scorpion Leiurus quinquestriatus.

The venom of the African scorpion Leiurus quinquestriatus was subjected to high-performance ion-exchange chromatography. Among a large number (greater than 25) of small proteins and other substances, a protein component of approx. 6500 Da was purified. The effect of this toxin was tested on single myelinated nerve fibres of the frog Rana esculenta. Toxin concentrations less than 10 nM produced clear effects. Activation rather than inactivation of the voltage-dependent sodium channel was strongly affected. Thus, this toxin from an African scorpion acts like the beta-toxins present in the venom of North American scorpions.

Animals↗
PubMed1987

Expression of the oxytocin gene in the large cells of the bovine corpus luteum.

In the bovine ovary there is a delay of 4-6 days between the observed maximum of oxytocin mRNA and the peak in the luteal levels of oxytocin nonapeptide. This implies a maturation process involving components of the post-translational processing pathway. In situ hybridization shows the oxytocin gene to be transcribed exclusively in the large cells of the corpus luteum at the beginning of the estrous cycle.

Animals↗
PubMed1987

[Pregnancy protein-1 in the serum of patients with diseases of the breast].

Pregnancy-specific beta 1-glycoprotein (SP1) was assayed by enzyme immunoassay in serum from 32 patients with breast diseases (11 mastopathies, 6 benign tumors and 15 breast cancers). Healthy blood donors were used as control group. There were significant differences between the SP1-serum concentrations of patient group (mastopathies, benign tumors, breast cancer) and the control group (p less than 0.001). The SP1-values of the groups with mastopathies, benign tumors and breast cancer did not differ significantly. Elevated SP1-concentrations were found in 4 of 11 patients with mastopathy, in 3 of 6 patients with benign tumor and in 10 of 15 patients with breast cancer versus 1 of 24 blood donors. With the help of SP1 determination in serum of 5 breast cancer patients before operation and 6 months post operation we did not found a correlation with further clinical course.

Adenocarcinoma, Scirrhous↗
PubMed1987

[Detection of specific antibodies to influenza viruses of the genital tract of mice following oral immunization].

Balb c-mice were immunized orally twice within 10 days with a live influenza vaccine (A PR 8/34, H1 N1). Specific antibodies were determined in sera, uterus homogenates and uterus lavage fluids. In all compartments specific antibodies of IgG class were estimated by means of an enzymimmunoassay. Regarding estrogen cyclus of mice the antibody titers were divided into diestrus, proestrus, estrus and metestrus. We have not seen any cyclic changes of antibody titers. The results support the concept of a common immune mucosal system. The continuous antibody titers during genital cyclus are evident for using oral vaccination aiming to induce secretory antibodies in genital tract.

Administration, Oral↗
PubMed1986

[Endometriosis of a scar].

We report on a case of cutaneous endometriosis having developed in the scar of a cesarean section. The slowly growing cutaneous nodule did not cause any cyclic pain or swelling. Histologic examination showed mainly histiocytic granulation tissue without multinuclear cells and extensive phagocytosis of hemosiderin. Only few tubular glands were seen.

Adult↗
PubMed1986

Expression of a mutant vasopressin gene: differential polyadenylation and read-through of the mRNA 3' end in a frame-shift mutant.

Sequence analysis of cDNA clones derived from hypothalamic mRNA of diabetes insipidus (Brattleboro) rats shows that the vasopressin gene transcript also includes the single base deletion demonstrated in the gene. This causes a frame-shift in the C terminus of the vasopressin precursor with a reading frame open through the 3' end of the mRNA including the poly(A) sequence. Antibodies raised against a synthetic tetradecapeptide (CP-14) corresponding to the frame-shifted C terminus identified a product of mol. wt approximately 26 000 in a reticulocyte lysate system programmed with Brattleboro hypothalamic mRNA. Immunohistochemical analysis indicated that a similar precursor is also present in vivo in neurones of the Brattleboro hypothalamus. Electrophoretic analysis of vasopressin mRNA from wild-type and mutant rat tissues revealed that (i) the hypothalamic mRNA from Brattleboro rats contains a longer stretch of poly(A) sequence than the wild-type strains; (ii) vasopressin mRNA is also present in the adrenal, ovary, testis and cerebellum, at very low levels; however, (iii) the extra-hypothalamic mRNA is considerably shorter than that in the hypothalamus because of a curtailed poly(A) sequence. Thus similar vasopressin gene transcripts are subject to a tissue-specific differential polyadenylation.

Amino Acid Sequence↗
PubMed1986

Immunocytochemical staining of supraoptic neurons from homozygous Brattleboro rats by use of antibodies against two domains of the mutated vasopressin precursor.

By use of antibody against the 14 amino acids in the mutated vasopressin precursor (CP-14) characteristic of the homozygous Brattleboro rat, an immunohisto- and -cytochemical study was performed on the supraoptic nuclei of homozygous Brattleboro rats. At the light-microscopic level, varying numbers of perikarya per section exhibited a positive reaction. The most intense staining was observed in a patchy manner on the peripheral portions of the cytoplasm, its central portion being stained less intensely. The antiserum did not react with the supraoptic perikarya of the Wistar rat. In the homozygous Brattleboro rat, antibodies against normal vasopressin only rarely resulted in a positive immunoreaction. However, when it was observed, incubation of the subsequent section with CP-14-antiserum suggested a co-localization of both peptides in the same perikaryon. At the ultrastructural level, CP-14 immunoreactivity was demonstrated on the secretory cisternae of the Golgi apparatus, on lysosome-like bodies and on parts of the rough endoplasmic reticulum. With the use of an antibody against normal vasopressin, immunoreactivity was confined to very limited areas of the rough endoplasmic reticulum. The oxytocin immunoreactivity in supraoptic perikarya of Brattleboro rats did not differ from that in the Wistar rat, either at the light- or at the electron-microscopic levels.

Animals↗
PubMed1986

Biosynthesis of vasopressin.

The nonapeptide vasopressin is synthetized as part of a longer common precursor polypeptide, together with its carrier protein neurophysin and a glycopeptide of unknown function. The gene for this common precursor has been isolated and sequenced and shown to comprise three exons encoding, respectively, the protein domains approximately corresponding to the N-terminal leader peptide and hormone, to most of the neurophysin, and to the glycopeptide. In the Brattleboro rat, the hereditary hypothalamic diabetes insipidus, characteristic of this strain, has been shown to be caused by a single nucleotide deletion in the vasopressin gene. This leads to the much reduced synthesis of a mutant vasopressin precursor, whose C terminus is quite unlike that in wild-type rats and which does not appear to be correctly processed in vivo.

DNA↗