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C Thiele

Publications and source records attributed to C Thiele.

At least 37 records · Page 2Linked to original sources
PubMed1997

Protein secretion: puzzling receptors.

All known sorting receptors for soluble cargo in the secretory pathway are transmembrane proteins. For sorting to the regulated pathway, however, a subpopulation of secretory proteins, associated with the membrane but not membrane-spanning, appears to link cargo and membrane in storage granule biogenesis.

Adrenocorticotropic Hormone↗
PubMed1997

Lack of phospholipase A2 mutations in neuroblastoma, melanoma and colon-cancer cell lines.

A candidate murine tumor-suppressor gene, Mom1, has been identified as the secretory phospholipase A2 (GDB nomenclature: PLA2G2A) gene. Evidence suggests that PLA2G2A functions as a tumor-suppressor because mice lacking PLA2G2A expression demonstrate increased colonic polyposis. The human homologue of PLA2G2A has been mapped to chromosome 1p36, a region frequently implicated in the pathogenesis of neuroblastoma, colon cancer and melanoma. We identified 2 alterations in the PLA2G2A gene in a single neuroblastoma cell line out of 20 examined; however, we found no mutations in 24 melanoma cell lines, 12 lymphoblastoid cell lines from patients having chromosome 1-linked familial melanoma and 10 colon cancer cell lines. Secretory phospholipase A2 is unlikely to play a significant role in the pathogenesis of these tumors.

Animals↗
PubMed1997

L(p) estimates for the bilinear Hilbert transform.

For the bilinear Hilbert transform given by: H fg(x) = p.v.integral f(x - y)g(x + y) dyy, we announce the inequality parallel H fg parallel (p(3) ) </= K(p(1) ) (,p(2) ) parallel f parallel (p(1) ) parallel g parallel (p(2) ), provided 2 < p(1), p(2) < infinity, 1/p(3) = 1/p(1) + 1/p(2) and 1 < p(3) < 2.

Journal Article↗
PubMed1996

Photoaffinity labeling of the human brain cholecystokinin receptor overexpressed in insect cells. Solubilization, deglycosylation and purification.

The human cholecystokinin B (CCKB) receptor was expressed in Sf9 cells by infection with recombinant baculovirus. For immunodetection a c-myc epitope tag (EQKLISEEDL) was fused at the amino-terminus of the CCKB receptor. In a second construct an additional hexa-histidine tag was introduced at the C-terminus of the CCKB receptor to enable employment of metal affinity chromatography. The two receptor constructs were expressed at densities of 6.0 +/- 1.1 pmol/mg protein and 7.2 +/- 1.1 pmol/mg protein, respectively which are 100-200-fold higher compared with the receptor amounts found in natural sources. Saturation of the binding sites with [3H]propionyl-CCK8 revealed Kd values of 4.5 +/- 0.5 nM and 7.8 +/- 0.6 nM for the CCKB receptor without or with histidine tag. In SDS/PAGE and subsequent immunodetection the histidine-tagged CCKB receptor migrated as a 55-kDa band, whereas the CCKB receptor without C-terminal modification revealed apparent molecular masses of 45 kDa and 49 kDa. The differences in the mass values observed for the two constructs suggest that the histidine tag could protect the CCKB receptor against proteolytical degradation from its C-terminus. Furthermore two new photoreactive derivatives of cholecystokinin octapeptide residues 26-33 (CCK8) with high labeling efficiency and specificity for the cholecystokinin receptor subtype B were developed: [3H]BzBz-des-Met28-[p-NH2Bz29]-CCK8 and [3H]BzBz-biotinyl-des-Met28-[p-NH2Bz29]-CCK8. Both contain the p-benzoyl-benzoyl (BzBz) residue at the N-terminus for photoactivation and a p-aminobenzoyl (p-NH2BZ) residue instead of Met28-Gly29 in cholecystokinin. Enzymatic deglycosylation of the CCKB receptor with N-glycosidase F after photoaffinity labeling demonstrated that the CCKB receptor with three potential glycosylation sites was slightly glycosylated, amounting to a molecular mass of about 4 kDa. Using the biotinylated cholecystokinin derivative the photoaffinity-labeled CCKB receptor could be purified 1260-fold by a two-step procedure including affinity chromatography on a streptavidin/avidin agarose matrix. For purification of the native receptor, an improved solubilization protocol for the CCKB receptor using dodecyl beta-D-maltopyranoside was developed. The solubilized CCKB receptors with C-terminal histidine tag retained their ligand binding characteristics after chromatography on a nickel affinity matrix.

Affinity Labels↗
PubMed1994

Photocleavable biotinylated ligands for affinity chromatography.

Two derivatives of the peptide hormone cholecystokinin (CCK-8s) containing a photocleavable o-nitrobenzylester group have been synthesized. One analog, [3H]4-(biotin-epsilon-Ahx-oxymethyl)-3-nitrobenzoyl-Gly-Orn (propionyl)-epsilon-Ahx-CCK-8s ([3H]BANA-CCK-8s), was biotinylated, while the other, 4-alanyloxymethyl-3-nitrobenzoyl-epsilon-Ahx-CCK-8s (ANA-CCK-8s) had a free amino group for coupling to amino-reactive affinity matrices. The analogs retained high affinity to both CCK receptors and anti-CCK antibodies. [3H]BANA-CCK-8s was bound to a streptavidin-agarose affinity matrix and was subsequently released by irradiation with uv light of wavelengths > 320 nm. The ability to recover a biotinylated peptide ligand from a streptavidin column under very mild conditions should be useful in the purification of specifically binding proteins. As a demonstration of this approach, [3H]BANA-CCK-8s was incubated with anti-CCK-antiserum and was subsequently passed over a streptavidin-agarose affinity matrix. After washing, the bound antibodies were eluted by photocleavage of the affinity ligand. Forty-six percent of the bound antibodies were recovered after 40 min of irradiation. The eluted antibodies showed essentially unchanged binding characteristics. The suitability of ANA-CCK-8s for the purification of anti-CCK antibodies was also demonstrated. The approach may prove to be generally useful in the isolation of labile proteins in an intact form.

Amino Acid Sequence↗
PubMed1994

Heterogeneity in hepatic transport of somatostatin analog octapeptides.

Hepatic transport of the synthetic somatostatin analog octreotide-SMS 201-995, (D)Phe-Cys-Phe-(D)Trp-Lys-Thr-Cys-Throl--and its novel derivative N-alpha-(alpha-D-glucosyl(1-4)-1-deoxy-D-fructosyl)-octreotide--SD Z CO-611, N-alpha-(alpha-D-glucosyl(1-4)-1-deoxy-D-fructosyl)-(D)Phe-Cys-Phe- (D)Trp-Lys-Thr-Cys-Throl--was studied. In rats SMS 201-995 showed a plasma elimination half-life of 1.2 +/- 0.2 hr; that of SDZ CO-611 was 1.9 +/- 0.3 hours. Within 120 min 66% of a mesenterically injected 4.4-nmol dose of SMS 201-995 was excreted in bile, but only 5.3% of SDZ CO-611 was excreted in bile. Biliary concentration of SMS 201-995 showed a maximum enrichment of 540-fold +/- 75-fold over peripheral blood concentration, indicating hepatic transport mechanisms different from simple diffusion. Comparison of plasma profiles of both peptides after mesenteric and femoral administration demonstrated the relative importance of hepatic extraction for SMS 201-995 but not for SDZ CO-611. The mode of extraction was studied by means of multiple-indicator dilution in isolated perfused rat liver, with inulin as nonpermeable marker. Ratio plots, ln([inulin]/[peptide]) vs. time, exhibited decreasing slopes for SMS 201-995, suggesting very rapid binding to hepatocyte membranes. The slope of the ratio plot of (inulin/SDZ CO-611) was almost zero even at low doses (down to 0.2 microgram), implying mainly extracellular distribution and nonhepatic elimination. Binding assays indicated the absence of somatostatin receptors in sinusoidal hepatocyte membranes. However, SMS 201-995 and SDZ CO-611 bound with high affinity to somatostatin receptors in rat cortical membranes. Multiple-indicator dilution experiments in presence of increasing cholyltaurine concentrations suggested an interaction of SMS 201-995 with sinusoidal bile salt transport. In isolated hepatocytes, uptake of SMS 201-995 was saturable and showed mutual inhibition with cholyltaurine. The results indicate that SMS 201-995 transport is different from receptor mediated endocytosis as known for peptide hormones and elimination pathways of SDZ CO-611 other than biliary excretion.

Animals↗
PubMed1993

Photoaffinity labeling of central cholecystokinin receptors with high efficiency.

A new photoreactive tritiated cholecystokinin (CCK) analogue was synthesized which contains the p-benzoylbenzoyl moiety linked to an ornithine residue at the N-terminus of the sulfated CCK octapeptide (CCK-8s). p-Benzoylbenzoyl-Orn(propionyl)-CCK-8s bound specifically and with high affinity to CCK binding sites in membranes both from pig cerebral cortex and from rat pancreatic membranes. The apparent dissociation constants KD were 1.2 nM and 0.5 nM, respectively. [3H]-p-Benzoylbenzoyl-Orn(propionyl)-CCK-8s was incubated with CCKB receptor preparations enriched by lectin chromatography and subsequently photoactivated. A polypeptide migrating with an apparent molecular weight M(r) of 56,000 in sodium dodecyl sulfate-polyacrylamide gel electrophoresis was specifically labeled. The labeling was suppressed by the CCKB receptor agonist pentagastrin. The efficiency of incorporation of radioactivity was high, reaching up to 70% of specifically bound radioactivity. After treatment with trifluoromethanesulfonic acid, the molecular weight of the labeled protein decreased to 45,000, indicating that the receptor is glycosylated. Photoaffinity labeling of CCKA receptors from rat pancreas resulted in the specific labeling of a protein band with M(r) of 80,000-100,000. Our synthetic approach should be useful for the design of photoreactive analogues of a variety of peptides. The high efficiency photolabeling of the CCKB receptor will be valuable for further characterization and purification of this receptor.

Affinity Labels↗
PubMed1992

A novel POU homeodomain gene specifically expressed in cells of the developing mammalian nervous system.

We report the isolation of a novel human POU domain encoding gene named RDC-1. The POU domain of the RDC-1 encoded protein is highly related to the POU domain potentially encoded by the rat brain-3 sequence and to that of the Drosophila I-POU protein; outside of the POU region, RDC-1 is unrelated to any previously characterized protein. The RDC-1 gene is expressed almost exclusively in normal tissues and transformed cells of neural origin. In the developing mouse and human fetus, RDC-1 is expressed in a spatially and temporally restricted pattern that suggests a critical role in the differentiation of neuronal tissues. In addition, RDC-1 is expressed in a unique subset of tumors of the peripheral nervous system including neuroepitheliomas and Ewing's sarcomas but not neuroblastomas. Based on its unique structural characteristics and expression pattern, we discuss potential functions for the RDC-1 protein.

Amino Acid Sequence↗
PubMed1989

[Long-term results following fibrinolytic treatment of deep venous thromboses in the area of the pelvis and leg].

68 patients who underwent fibrinolytic treatment due to deep vein thrombosis of the lower extremity were followed-up after a median time interval of 6.3 years. Phlebography was carried out in all patients prior to and following fibrinolytic treatment. 28% of all patients showed complete patency and 38% partial patency. 34% showed no improvement. For the long term follow-up, physical examination, doppler-sonography, phlebodynamometry and vein occlusion plethysmography were assessed. The acute intervention, regarding treatment, turned out to be the crucial prognostic parameter. While late symptoms and clinical findings on the one hand and site, extent and age of thrombosis prior to fibrinolytic treatment on the other hand did not correlate with one another, symptoms and clinical findings did indeed correlate quite well with the outcome of fibrinolytic treatment. Postthrombotic syndrom was rare in cases with complete patency. In cases where patency was only partially or not at all achieved, postthrombotic syndrom was present to a higher degree the more central and the more extensive the remaining thrombosis was.

Adolescent↗
PubMed1986

Regulation of the in vitro monoclonal immunoglobulin production in cultures of peripheral blood mononuclear cells and bone marrow cells from myeloma patients mediated by T cell dependent mitogens.

In vitro monoclonal immunoglobulin (mIg) production of cultured tumour cells--prepared from the bone marrow (BM) or from the peripheral blood (PB) of 40 multiple myeloma (MM) patients, 16 patients with monoclonal gammopathy of undetermined significance and two patients with M. Waldenström--was measured with an enzyme-linked immunosorbent assay (ELISA) using anti-idiotype and anti-class specific antisera. After in vitro stimulation with pokeweed mitogen (PWM) or OKT3 antibody, mIg production was regularly suppressed in BM cell cultures, whereas enhanced, unaltered or suppressed production was observed in PB cell cultures. These observations show that the expanded clone in MM can still be regulated in vitro. Separation experiments demonstrated the involvement of T cells in this in vitro system. The results could be explained by the hypothesis that activated T cells can suppress mature cells of B cell differentiation, as found in BM of the patients, but stimulate earlier B cells from the peripheral blood towards differentiation into Ig secreting cells.

Antibodies, Monoclonal↗
PubMed1986

[Use of ketamine anesthesia in experimental animal investigations].

The use of the Ketamine anesthesia as an intramuscular injection proved itself as favourable in the animal experimental investigation. The duration of effect amounts to 20-30 minutes at a doses of 5-8 mg/kg body weight. Protective reflexes are preserved. The Ketamine anesthesia is qualified for difficult examination techniques thereby. Surgical interventions including the laparotomy become well-tolerated. The use of Ketamine is simple. The postoperative care is uncomplicated by the continuous analgesic effect.

Anesthesia, General↗