Neuropeptide Y expression in animal models of temporal lobe epilepsy.
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Amygdala↗
Biomedical subjects
E Rupp
Publications and source records attributed to E Rupp.
Optical investigations of defects in Cd1-xZnxTe.
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Journal Article↗
Demonstration of functionally different interactions between phospholipase C-gamma and the two types of platelet-derived growth factor receptors.
Phosphorylated tyrosine residues in receptor tyrosine kinases serve as binding sites for signal transduction molecules. We have identified two autophosphorylation sites, Tyr-988 and Tyr-1018, in the platelet-derived growth factor (PDGF) alpha-receptor carboxyl-terminal tail, which are involved in binding of phospholipase C-gamma (PLC-gamma). The capacities of the Y988F and Y1018F mutant PDGF alpha-receptors, expressed in porcine aortic endothelial cells, to bind PLC-gamma are 60 and 5% of that of the wild-type receptor, respectively. Phosphorylated but not unphosphorylated peptides containing Tyr-1018 are able to compete with the intact receptor for binding to immobilized PLC-gamma SH2 domains; a phosphorylated Tyr-988 peptide competes 10 times less efficiently. The complex between PLC-gamma and the PDGF alpha-receptor is more stable than that of PLC-gamma and the PDGF beta-receptor. However, PDGF stimulation results in a smaller fraction of tyrosine-phosphorylated PLC-gamma and a smaller accumulation of inositol trisphosphate in cells expressing the alpha-receptor as compared with cells expressing the beta-receptor. We conclude that phosphorylated Tyr-988 and Tyr-1018 in the PDGF alpha-receptor carboxyl-terminal tail bind PLC-gamma, but this association leads to only a relatively low level of tyrosine phosphorylation and activation of PLC-gamma.
Amino Acid Sequence↗
A unique autophosphorylation site in the platelet-derived growth factor alpha receptor from a heterodimeric receptor complex.
The platelet-derived growth factor (PDGF) alpha and beta receptors undergo dimerization as a consequence of ligand binding. Depending on the PDGF isoform (PDGF-AA, -AB or -BB), homodimers or heterodimers of receptors are formed. In this study, we have used transfected porcine aortic endothelial cells, coexpressing cDNAs for the alpha receptor and the beta receptor at comparable levels, to investigate the properties of the alpha beta-heterodimeric receptor complex. PDGF-AB, which mainly induced alpha beta-heterodimeric complexes, was the most efficient isoform for stimulating mitogenicity. Actin reorganization, in the form of circular membrane ruffling and chemotaxis, was induced by PDGF-AB and PDGF-BB, but not by PDGF-AA, thus indicating that the beta receptor in the homodimeric or heterodimeric configuration was required for induction of motility responses. The molecular basis for the apparent receptor dimer-specific properties was examined by analyzing receptor autophosphorylation and phosphorylation of substrates. The alpha receptor was found to be phosphorylated at an additional tyrosine residue, Tyr754, in the heterodimeric complex as compared to the alpha alpha receptor homodimer. Phosphorylation of this tyrosine residue could permit the binding of a specific signal-tranducing protein. A candidate is a 134,000-M(r) protein, which was shown to associate preferentially with the alpha receptor in the heterodimeric receptor complex. It is possible that phosphorylated Tyr754 in the alpha receptor mediates activation of specific signal-tranducing molecules like the 134,000-M(r) substrate, and thereby initiates signal-tranduction pathways from the alpha beta receptor heterodimer, which are distinct from those initiated via homodimeric receptor complexes.
Amino Acid Sequence↗
Differential NPY mRNA expression in granule cells and interneurons of the rat dentate gyrus after kainic acid injection.
Using in situ hybridization histochemistry neuropeptide Y (NPY) mRNA expression was investigated after intraperitoneal injection of kainic acid (KA) and after local application of KA or quinolinic acid into the dentate gyrus of the rat. Enhanced concentrations of NPY mRNA were observed in interneurons of the hilus, including presumptive fusiform neurons and pyramidal-shaped basket cells already 4 hours after initiation of limbic seizures by KA (10 mg/kg, i.p.). Increased NPY expression persisted in neurons resistant to seizure-induced cell death (6-48 h after i.p. KA). Exceptionally high hybridization signals were found in interneurons of the hilus and the CA1 and CA3 sectors 8 months after KA-induced limbic seizures. In the granule cell layer only a transient but pronounced increase in NPY mRNA was observed 12-24 h after injection. Only moderate changes were observed in this cell layer at later intervals. Anticonvulsant treatment with thiopental, after a brief period of generalized seizures, prevented the increase in NPY mRNA in granule cells but not in interneurons. No change in NPY message was found also in granule cells of rats which responded with mild "wet dog shake" behavior but not with motor seizures to KA injection. Local injections of low doses of KA (0.05-0.2 nmol) or quinolinic acid (6.5-100 nmol) into the dentate gyrus of the hippocampus under deep thiopental anesthesia, after 24 h, resulted in increased concentrations of NPY message in interneurons of the ipsilateral, but not of the contralateral hilus and not in granule cells.(ABSTRACT TRUNCATED AT 250 WORDS)
Animals↗
Tyr-716 in the platelet-derived growth factor beta-receptor kinase insert is involved in GRB2 binding and Ras activation.
Ligand stimulation of the platelet-derived growth factor (PDGF) beta-receptor leads to activation of its intrinsic tyrosine kinase and autophosphorylation of the intracellular part of the receptor. The autophosphorylated tyrosine residues mediate interactions with downstream signal transduction molecules and thereby initiate different signalling pathways. A pathway leading to activation of the GTP-binding protein Ras involves the adaptor molecule GRB2. Here we show that Tyr-716, a novel autophosphorylation site in the PDGF beta-receptor kinase insert, mediates direct binding of GRB2 in vitro and in vivo. In a panel of mutant PDGF beta-receptors, in which Tyr-716 and the previously known autophosphorylation sites were individually mutated, only PDGFR beta Y716F failed to bind GRB2. Furthermore, a synthetic phosphorylated peptide containing Tyr-716 bound GRB2, and this peptide specifically interrupted the interaction between GRB2 and the wild-type receptor. In addition, the Y716(P) peptide significantly decreased the amount of GTP bound to Ras in response to PDGF in permeabilized fibroblasts as well as in porcine aortic endothelial cells expressing transfected PDGF beta-receptors. The mutant PDGFR beta Y716F still mediated activation of mitogen-activated protein kinases and an increased DNA synthesis in response to PDGF, indicating that multiple signal transduction pathways transduce mitogenic signals from the activated PDGF beta-receptor.
Adaptor Proteins, Signal Transducing↗
Recombinant human retinoic acid receptor alpha. Binding of DNA and synthetic retinoids to the protein expressed in Escherichia coli.
The human retinoic acid receptor alpha was expressed in Escherichia coli. The recombinant protein was found to be very unstable in several E. coli strains, probably due to proteolysis. Conditions were established to obtain reasonable amounts of active protein for ligand and DNA binding studies. The recombinant receptor showed the expected DNA binding activities in gel-retardation assays. Ligand binding properties were measured in a charcoal absorption assay. The dissociation constant for highly specific bound retinoic acid was found to be 0.67 nM. The affinity of several synthetic retinoids to the recombinant protein was determined and compared to their biological activity. Some of the values presented here differ significantly from those published earlier for the receptor or its isolated hormone-binding domain.
Amino Acid Sequence↗
The promoter of the human parathyroid hormone gene contains a functional cyclic AMP-response element.
We have screened the sequence of the 394 base pairs upstream of the main transcriptional start site of the promoter of the human parathyroid hormone (PTH) gene for well-known protein recognition motifs with the aim to identify potential positive or negative regulatory elements. Within this region we found a potential cAMP-response element (CRE) besides several other putative binding sites for transcription factors. We fused promoter regions that contain this element and extend beyond the transcription start site to an appropriate reporter gene (CAT) and transfected different cell lines with these constructs. Transient expression of the CAT gene from these hybrid genes could be shown to be significantly stimulated by forskolin or isoproterenol thus proving the responsiveness of the whole promoter region towards elevated cAMP levels. DNase I protection studies revealed protein binding around the putative CRE (PTH-CRE) and an adjacent CCAAT element. Gel retardation assays with the PTH-CRE as well as the well-characterized CRE from the rat somatostatin promoter indicated specific binding of the same protein to both elements, although with a slightly reduced affinity of the PTH-CRE. Both of these elements were also able to confer cAMP-responsiveness to a heterologous promoter.
Animals↗
Intravenous infusions of nitroprusside, dobutamine, and nitroglycerin are compatible.
It is now customary practice to couple separately metered infusions via a manifold to a common catheter that enters the patient. Nitroprusside, however, is considered incompatible with all other medications. Critically ill patients who require multiple infusions of vasoactive and inotropic medications would benefit if physicians had additional information regarding compatibility of nitroprusside with other commonly used infusions. Utilizing high-performance liquid chromatography, the authors investigated the physical and chemical compatibility of nitroprusside, dobutamine, and nitroglycerin in solutions of 5% dextrose or 0.9% NaCl at clinically relevant concentrations. All drugs were present within the guidelines of the U.S. Pharmacopeia (+/- 10%) over 24 h in NaCl, but nitroglycerin degraded over 24 h when the three drugs were mixed in dextrose. We recommend diluting these medicines in NaCl when mixtures of them would exist for greater than 4 h.
Dobutamine↗
Identification of a high-affinity receptor for interleukin 1 alpha and interleukin 1 beta on cultured human rheumatoid synovial cells.
In this report the binding of recombinant human interleukins 1 alpha and 1 beta (rIL-1 alpha and rIL-1 beta) to primary cultures of human rheumatoid synovial cells is measured and compared to the concentrations of these mediators required for stimulation of PGE2 production by these same cells. The average concentration of IL-1 alpha required for half-maximal stimulation of PGE2 was 4.6 +/- 1.5 pM (+/- SEM) (n = 6), whereas for IL-1 beta half-maximal stimulation was observed at a concentration of 1.3 +/- 0.24 pM (n = 6). Both direct and competitive binding experiments were performed. In direct binding experiments, IL-1 alpha bound with a Kd of 66 pM (n = 1), while IL-1 beta bound with a Kd of 4 pM (n = 2). In competitive binding experiments, IL-1 alpha inhibited binding of 125I-IL-1 alpha with a Ki of 33-36 pM (n = 2) and binding of 125I-IL-1 beta with a Ki of 51-63 pM (n = 2). IL-1 beta inhibited binding of 125I-IL-1 alpha with a Ki of 2-3 pM (n = 2) and binding of 125I-IL-1 beta with a Ki of 7 pM (n = 2). The binding data were best fit by a model specifying a single class of receptors with homogeneous affinity for either IL-1 alpha or IL-1 beta and with an abundance of 3,000-14,000 sites per cell. Autoradiography showed that the vast majority of the synoviocytes within the cultures possessed IL-1 receptors. Comparison of biological response curves with the binding curves indicates that the observed receptors exhibit sufficiently high affinity to mediate the response of human synoviocytes to low picomolar concentrations of IL-1 alpha and IL-1 beta.
Arthritis, Rheumatoid↗
Identification of a high-affinity receptor for native human interleukin 1 beta and interleukin 1 alpha on normal human lung fibroblasts.
Native human IL-1 beta and IL-1 alpha stimulated prostaglandin E2 secretion by human embryonic lung fibroblasts at half-maximal concentrations of 3 +/- 1.2 pM (+/- SEM) and 10 +/- 2.3 pM, respectively. In contrast to the 20-50-fold lower affinities previously found for IL-1-R on 3T3 cells as well as murine and human lymphoblastoid lines, monoiodo 125I-IL-1 beta bound to normal human fibroblasts with a Kd of 8.4 +/- 4.1 pM in direct binding experiments, and with a Ki of 11.2 +/- 2.8 pM in competitive binding experiments. IL-1 alpha bound to the receptor identified by 125I-IL-1 beta with a Ki of 50 +/- 18 pM. The receptor exhibited homogeneous affinity for IL-1 beta or IL-1 alpha. The receptor did not recognize IL-2, IFN-gamma, tumor necrosis factor alpha, a functionally related monokine, or bovine acidic fibroblast growth factor, a structurally related mediator. Comparison of the biological response curves and binding curves obtained for IL-1 alpha and IL-1 beta showed that they were parallel and that 10-15% occupancy of the estimated 3,000 sites by either species of IL-1 was sufficient to give half-maximal stimulation of prostaglandin E2 secretion. Thus, the amount of apparent signal amplification observed on fibroblasts was considerably lower than the 100-100,000 fold amplification previously reported for lymphoid lines. Crosslinking experiments revealed a major band with a corrected molecular mass of approximately 80 kD and a minor band of approximately 200 kD. Labeling of these bands was blocked by IL-1 beta and IL-1 alpha but not by IL-2, IFN-gamma, or tumor necrosis factor alpha. These results demonstrate that normal human embryonic lung fibroblasts bear IL-1-R of sufficiently high affinity to mediate their biological responsiveness to low picomolar concentrations of IL-1 beta and IL-1 alpha and are consistent with the existence of a single receptor mediating the biological properties of both human IL-1 species.
Binding, Competitive↗
Beyond palliative mastectomy in inflammatory breast cancer--a reassessment of margin status.
BACKGROUND: Inflammatory breast cancer is a locally advanced tumor with an aggressive local and systemic course. Treatment of this disease has been evolving over the last several decades. The aim of this study was to assess whether current therapies, both surgical and chemotherapeutic, are providing better local control (LC) and overall survival (OS). We also attempted to identify clinical and pathologic factors that may be associated with improved OS, disease-free survival (DFS), and LC. METHODS: A 25-year retrospective review performed at the City of Hope National Medical Center identified 90 patients with the diagnosis of inflammatory breast cancer. RESULTS: Of the 90 patients identified with inflammatory breast cancer, 33 received neoadjuvant therapy (NEO) consisting of chemotherapy followed by surgery with radiation (n = 26) and without radiation (n = 7). Fifty-seven patients received other therapies (nonNEO). Treatments received by the nonNEO group consisted of chemotherapy, radiation, mastectomy, adrenalectomy, and oophorectomy, alone or in combination. The median follow-up was 28.9 months for the NEO group and 17.6 months for the nonNEO group. Borderline significant differences in the OS distributions between the two groups were found (P = .10), with 3- and 5-year OS for the NEO group of 40.0% and 29.9% and for the nonNEO group of 24.7% and 16.5%, respectively. DFS and LC were comparable in the two groups. Lower stage was associated with an improved OS (P < .05). The 5-year OS for stage IIIB was 30.9%, compared to 7.8% for stage IV. In those patients with stage III disease who were treated with mastectomy and rendered free of disease, margin status was identified by univariate analysis to be a prognostic indicator for OS (P < .05). The 3-year OS, DFS, and LC for patients with negative margins were 47.4%, 37.5%, and 60.3%, respectively, compared to 0%, 16.7%, and 31.3% in patients with positive margins. CONCLUSIONS: This study suggests that in patients with inflammatory breast cancer and nonmetastatic disease, an aggressive surgical approach may be justified with the goal of a negative surgical margin. Achievement of this local control is associated with a better overall outcome for this subset of patients. The ability to obtain negative margins may further identify a group of patients with a less aggressive tumor biology that may be more responsive to other modalities of therapy.
Adult↗