Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P01189 (beta-endorphin)
 21,003 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

There has been considerable effort in chemically conjugating a variety of plant and bacterial toxins to monoclonal antibodies that are directed to surface antigens on target cells. Coupling has been mediated through disulfide linkage, and the resulting conjugates are known generically as immunotoxins. In general, there are a few shortfalls to this approach. For example, since it is clear that not all surface antigens are internalized, one cannot predict the fate of a given IT once bound to its determinant on the surface of a target cell. In addition, in most instances one must activate the amino moiety of lysine residues with a heterobifunctional reagent in order to form disulfide linkage between the ligand and toxophore components. Since the number of reactive groups may be large, the disulfide linked conjugate molecules most likely represent a family of isomeric molecules rather than a defined protein. As a result, one cannot readily manipulate the fine structure of an IT in order to probe the mechanism of toxophore entry into the target cell. The approach that our group has taken toward the development of targeted cytotoxins, however, differs in a fundamental way: Rather than chemically coupling the ligand with toxophore through a disulfide bond, we have turned to genetic engineering in order to create gene fusions whose chimeric products are joined through a peptide bond. Thus, we have genetically constructed a family of fusion genes in which the receptor binding domain of diphtheria toxin has been deleted and replaced with DNAs encoding either alpha-MSH or IL-2. In each instance, it was known that the polypeptide ligand component of the fusion protein bound to specific receptors on target cells and was internalized by receptor mediated endocytosis. We reasoned, therefore, that the substitution of the diphtheria toxin receptor binding domain by these ligands should result in the formation of 'new' toxins whose action should be targeted toward selected eukaryotic cells that expressed either the alpha-MSH or IL-2 receptor. As along as the ligand component was exposed on the surface of the chimeric toxin, the molecule should bind to its receptor and be drawn into the cell by receptor-mediated endocytosis. Since the toxin-related/peptide hormone fusion protein is the product of a chimeric gene, it is a single molecular species. This has allowed us to begin to probe by site-directed mutagenesis the structure of fragment B sequences that are required to facilitate the translocation of fragment A across the target cell membrane.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Diphtheria-related peptide hormone gene fusions: a molecular genetic approach to chimeric toxin development. 290 22

We studied five cases of central nervous system neuronal tumor, one gangliocytoma and four gangliogliomas, both ultrastructurally and immunohistochemically, using antibodies to neuroendocrine markers including tyrosine hydroxylase (TH), serotonin (5HT), somatostatin (SOM), met-enkephalin (MEK), leu-enkephalin (LEK), substance P (SP), gastrin, vasopressin, oxytocin, vasoactive intestinal polypeptide, adrenocorticotropic hormone and calcitonin. In all cases, the presence of dense-core vesicles (60-250 nm) in the neuronal elements was the characteristic ultrastructural finding. Synapses were observed in two cases. Immunohistochemically, variable numbers of neuronal cells showed positive staining for SOM in five cases, TH, MEK and LEK in three cases, and 5HT and SP in one case each. The others were negative. Positive immunoreactivity for multiple markers was shown in all cases. SOM, TH, 5HT and SP were present in the small- to medium-sized cells, while MEK and LEK were almost exclusively confined to the large cells. Our study clearly indicated that these tumors contained neuronal cells which were not homogeneous with regard to neuroendocrine markers.
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PMID:Neuroendocrine markers in central nervous system neuronal tumors (gangliocytoma and ganglioglioma). 292 88

To determine whether changes in circulating levels of neuropeptides are associated with symptoms of premenstrual syndrome (PMS), 20 women with the diagnosis of PMS and 20 asymptomatic subjects were studied. The premenstrual beta-endorphin levels were significantly lower in PMS patients (P = 0.0001). The decrease in beta-endorphin levels during the luteal phase, compared with the follicular phase, in PMS patients was also significant (P = 0.0002). Neurotensin, human pancreatic peptide, vasoactive intestinal polypeptide, gastrin, and bombesin-like immunoreactivity levels did not reveal significant changes between days 7 and 25 in patients with PMS.
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PMID:Neuropeptide levels in premenstrual syndrome. 293 73

The bandwidths of several polypeptides related to human beta-endorphin have been investigated with different n-alkylsilica stationary phases and different elution gradients of 0.1% trifluoroacetic acid-water-acetonitrile mobile phases. In particular, we have examined the influence of changes in the gradient steepness parameter, b, on peakwidth with five different octadecylphases, chemically bonded to porous spherical silica particles of nominally 4 micron and 6 micron average particle diameter, respectively. The effect on the zone dispersion of these polypeptide solutes as the average pore diameter of the silica matrix was increased from 7.3 nm to 30 nm with stationary phases of similar ligand densities packed into columns of identical configuration has been further documented. The experimental data on solute bandwidths and peak capacities are comparable with the corresponding bandwidth and peak capacity values calculated from analytical equations, derived from the general plate height theory and from gradient elution theory. These comparisons clearly demonstrate that anomalous bandbroadening phenomena may occur when polypeptides are eluted with steep gradients, i.e. with gradients of large b values. Moreover, as the relative chromatographic residence times of beta-endorphin peptides capable of forming a C-terminal amphiphilic secondary structures is increased, i.e. as the dwell times and median capacity factors, k, for such peptides are increased, significant divergencies arise between the observed peakwidth behaviour and the behaviour predicted by analytical relationships which describe either the dependency of peak bandwidth (as 4 sigma v) on the gradient steepness parameter, b, or the dependency of peak capacity on gradient time, tG, median capacity factor, k, and the Knox parameter, C, respectively. The importance of these divergences from the predicted bandwidth and peak capacity behaviour for polypeptides separated on reversed phases, and for resolution optimisation in particular, is evaluated. These investigations thus enable further assessment of the quantitative relevance of current models that describe polypeptide zone migration under gradient elution reversed-phase chromatographic conditions in which solute-dependent slow equilibria, mediated by conformational or solvation effects, may still occur.
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PMID:High-performance liquid chromatography of amino acids, peptides and proteins. LXVII. Evaluation of bandwidth relationships of peptides related to human beta-endorphin, separated by gradient-elution reversed-phase high-performance liquid chromatography. 293 99

Arachnoiditis was produced experimentally in male albino ICR mice by intrathecal injection of meglumine iocarmate . A control group received intrathecal injection of an electrolyte solution resembling CSF. Eight weeks after injection, the brains and spinal cords were removed for brain beta-endorphin and spinal cord met-enkephalin measurement by radioimmunoassay, and the dural sacs were removed for histologic examination to confirm the presence or absence of arachnoiditis. Brain beta-endorphin content was significantly reduced and spinal-cord enkephalin concentration was significantly elevated in iocarmate-treated animals. The dura and arachnoid in the treated mice were thickened and infiltrated with lymphocytes. These studies indicate that arachnoiditis alters endogenous polypeptide concentrations.
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PMID:Brain beta-endorphin and spinal-cord enkephalin concentrations in experimental arachnoiditis. 295 48

Anomalous band broadening of beta-endorphin related polypeptides chromatographed on hydrophobic high performance stationary phases can be attributed to ligand induced conformational changes associated with polypeptide folding. In the presence of anionic lipids the size exclusion chromatographic behaviour of members of the beta-endorphin family also exhibits similar behaviour. These structure-retention and band broadening behaviour of these polypeptides were in accord with predictions made by hydropathy algorithms and amphipathic helix representations. These observations on surface accessibility of key amino acid residues and their interaction as a conformationally induced domains with stationary phase ligands are equally relevant to other peptidic solutes and neurotransmitters.
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PMID:Reverse phase liquid chromatography of beta-endorphins and related peptides. 295 74

In addition to corticotropin-releasing factor (CRF) and structurally related peptides, arginine vasopressin (AVP), oxytocin, angiotensin II, vasoactive intestinal polypeptide, peptide histidine isoleucinamide, epinephrine (E), and norepinephrine induce secretion of adrenocorticotropin (ACTH) from corticotropic cells in vitro. The apparent affinity and intrinsic ACTH-releasing activity of these substances are lower than those of CRF. These substances can also act synergistically with CRF. In this paper the role of catecholamines and AVP in the control of ACTH release is discussed. Infusion i.v. of E increases plasma ACTH and corticosterone to levels that are normally found during stress. E-induced stimulation of pituitary-adrenal activity is mediated by beta adrenoceptors and involves release of CRF, because it can be prevented by beta-adrenoceptor blockers and by destruction of CRF neurons (hypothalamic lesions), blockade of CRF release (chlorpromazine, morphine, and Nembutal), or administration of CRF antiserum. Although stress can cause a vast increase in plasma E, circulating E is not essential for the acute stress-induced release of ACTH because blockade of beta (or alpha) adrenoceptors, administration of chlorisondamine, or extirpation of the adrenal medulla and sympathectomy do not prevent the pituitary-adrenal response to stress. In contrast, circulating E plays a major role in the release of intermediate-lobe peptides during emotional stress. Studies of the role of AVP in pituitary-adrenal control by the use of pressor receptor (V1) antagonists are not valuable because of the ineffectiveness of such antagonists in blocking AVP-induced release of ACTH from corticotropic cells in vitro. Treatment of rats with an antiserum to AVP reduces the ACTH response to stress. We conclude that AVP has an important role in stress-induced activation of the pituitary-adrenal system, possibly by potentiating the effects of CRF.
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PMID:Role of epinephrine and vasopressin in the control of the pituitary-adrenal response to stress. 298 37

The effect of endotoxin (lipopolysaccharide from E. coli) on isolated adrenocortical cells was examined. Lipopolysaccharide decreased the ACTH-induced steroidogenesis. This effect was shown by all corticotropin concentrations studied, and the longer the incubation time, the higher the effect produced. The rate of decrease of ACTH-induced steroidogenesis was dependent on the concentration of lipopolysaccharide in the medium. Binding of [125I]ACTH to adrenocortical cells was modified by lipopolysaccharide; this modification was related to a decrease of the ACTH-induced steroidogenesis. This effect supports the hypothesis of a direct interaction between lipopolysaccharide and the cell membrane with a concomitant distortion of the cell surface affecting the ACTH receptor sites of their environment. [14C]Lipopolysaccharide binds to isolated adrenocortical cells. Binding specificity was investigated by competitive experiments in the presence of various types of endotoxins, polypeptide hormones and proteins. Unlabelled lipopolysaccharide from the same bacterial strain and isolated under identical conditions than the labelled lipopolysaccharide exerted the strongest inhibitory activity. Unlabelled lipopolysaccharide of various strains different from that originating the labelled lipopolysaccharide exerted the less displacement. It would imply a certain kind of specificity but the decrease in the binding of lipopolysaccharide produced by ACTH and glucagon suggests the existence of non-specific interactions between lipopolysaccharide and cell membrane.
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PMID:Influence of E. coli endotoxin on ACTH induced adrenal cell steroidogenesis. 298 73

By the peroxidase-antiperoxidase technique, the authors studied 7 malignant choroidal melanomas, 7 conjunctival nevi and 1 malignant conjunctival melanoma with the aim to detect the presence of vasoactive intestinal polypeptide (VIP), adrenocorticotropic hormone (ACTH), gastrin, estradiol and testosterone. Positive staining reaction for VIP, estradiol and testosterone was observed in both malignant melanomas of the choroid and conjunctival nevi. The case of conjunctival melanoma was positive for VIP and ACTH but not for estradiol and gastrin.
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PMID:Steroids and neuroendocrine hormones detected by the immunoperoxidase technique from malignant melanomas and nevi of the choroid and conjunctiva. 301 Feb 9

Interleukin 1 (IL1) is a macrophage-derived polypeptide which signals neurons in the preoptic-anterior hypothalamus to initiate fever and the acute-phase glycoprotein response. Recently, increases in cerebrospinal fluid and hypothalamic levels of beta-endorphin have been reported during endotoxin (LPS)- and IL1-induced fevers, suggesting that this opioid may participate in the modulation of IL1 effects in the CNS. In this study, we investigated whether purified (human) IL1 influences the specific binding of three prototypic opioid agonists (2-D-alanine-5-L-methionineamide, DAME; (-)-ethylketocyclazocine, EKC; dihydromorphine, DHM) and one antagonist (naloxone) to opioid receptor-enriched membrane preparations in cerebral cortex, hypothalamus, midbrain, pons, medulla, and cerebellum of guinea pig brain. IL1 reduced the binding of these ligands to their receptors during a 30-min incubation. The extent of IL1 inhibition of a given ligand for its binding sites varied according to the brain region; within some regions, the extent of this inhibition also varied with the four ligands tested. But in cortex the effect of IL1 on the specific binding of DHM is dose-dependent. Similar results were obtained with crude homologous IL1. S. enteritidis endotoxin, suspended in pyrogen-free saline at concentrations from 4 to 36 micrograms/ml, did not inhibit the binding of these opioid ligands to their receptors in any brain region. These results indicate that IL1 interacts with the opiate receptors in guinea pig brain. This interaction, moreover, is not limited to the hypothalamus alone, the primary site of the pyrogenic action of IL1, but also occurs in other brain regions.
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PMID:Interleukin 1 reduces opioid binding in guinea pig brain. 301 Feb 57


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