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Schwyzer R, Iselin B, Rittel W, Sieber P. Synthesen zyklischer Polypeptide. c-Tetraglycyl und c-Hexaglycyl. Über aktivierte Ester VII. Helv Chim Acta 2004. [DOI: 10.1002/hlca.19560390331] [Citation(s) in RCA: 84] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Diokno A, Sand P, Labasky R, Sieber P, Antoci J, Leach G, Atkinson L, Albrecht D. Long-term safety of extended-release oxybutynin chloride in a community-dwelling population of participants with overactive bladder: a one-year study. Int Urol Nephrol 2003; 34:43-9. [PMID: 12549638 DOI: 10.1023/a:1021372426421] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
In this multicenter, open-label study of extended- and immediate-release oxybutynin chloride, community-dwelling participants were studied for up to 12 months to evaluate the long-term safety profile of extended-release oxybutynin. Quality-of-life assessments designed to measure the impact of incontinence and evaluate treatment outcome were used to study subjective improvement. A total of 904 women and 163 men (mean age 64 years, range 29-91 years) were enrolled. The majority of discontinuations were in the first 3 months (25.5%); of those who continued after 3 months, 62% remained on extended-release oxybutynin chloride for one year. The majority of discontinuations were for adverse events; dry mouth was the most frequently cited event leading to discontinuation (8.4%). Significant improvements were seen in QOL measures. Long-term therapy with extended-release oxybutynin chloride was generally well tolerated and effective, improving quality of life significantly in participants with overactive bladder over 3-12 months of therapy.
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53
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Sieber P, Schorderet M, Ryser U, Buchala A, Kolattukudy P, Métraux JP, Nawrath C. Transgenic Arabidopsis plants expressing a fungal cutinase show alterations in the structure and properties of the cuticle and postgenital organ fusions. Plant Cell 2000; 12:721-738. [PMID: 10810146 DOI: 10.2307/3870997] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
A major structural component of the cuticle of plants is cutin. Analysis of the function of cutin in vivo has been limited because no mutants with specific defects in cutin have been characterized. Therefore, transgenic Arabidopsis plants were generated that express and secrete a cutinase from Fusarium solani f sp pisi. Arabidopsis plants expressing the cutinase in the extracellular space showed an altered ultrastructure of the cuticle and an enhanced permeability of the cuticle to solutes. In addition, pollen could germinate on fully differentiated leaves of cutinase-expressing plants but not on control leaves. These differences coincided with strong postgenital organ fusions. The junctions of the fusions contained pectic polysaccharides. As fused organs grew apart from each other, organ deformations and protrusions of epidermal cells developed at positions with high mechanical stress. These results demonstrate that an intact cutin layer not only is important for plant-environment interactions but also prevents fusions between different plant organs and is therefore necessary for normal epidermal differentiation and organ formation.
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Affiliation(s)
- P Sieber
- Department of Biology, Unit of Plant Biology, University of Fribourg, CH-1700 Fribourg, Switzerland
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Sieber P, Schorderet M, Ryser U, Buchala A, Kolattukudy P, Métraux JP, Nawrath C. Transgenic Arabidopsis plants expressing a fungal cutinase show alterations in the structure and properties of the cuticle and postgenital organ fusions. Plant Cell 2000; 12:721-38. [PMID: 10810146 PMCID: PMC139923 DOI: 10.1105/tpc.12.5.721] [Citation(s) in RCA: 200] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/19/1999] [Accepted: 03/10/2000] [Indexed: 05/18/2023]
Abstract
A major structural component of the cuticle of plants is cutin. Analysis of the function of cutin in vivo has been limited because no mutants with specific defects in cutin have been characterized. Therefore, transgenic Arabidopsis plants were generated that express and secrete a cutinase from Fusarium solani f sp pisi. Arabidopsis plants expressing the cutinase in the extracellular space showed an altered ultrastructure of the cuticle and an enhanced permeability of the cuticle to solutes. In addition, pollen could germinate on fully differentiated leaves of cutinase-expressing plants but not on control leaves. These differences coincided with strong postgenital organ fusions. The junctions of the fusions contained pectic polysaccharides. As fused organs grew apart from each other, organ deformations and protrusions of epidermal cells developed at positions with high mechanical stress. These results demonstrate that an intact cutin layer not only is important for plant-environment interactions but also prevents fusions between different plant organs and is therefore necessary for normal epidermal differentiation and organ formation.
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Affiliation(s)
- P Sieber
- Department of Biology, Unit of Plant Biology, University of Fribourg, CH-1700 Fribourg, Switzerland
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55
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Schiefthaler U, Balasubramanian S, Sieber P, Chevalier D, Wisman E, Schneitz K. Molecular analysis of NOZZLE, a gene involved in pattern formation and early sporogenesis during sex organ development in Arabidopsis thaliana. Proc Natl Acad Sci U S A 1999; 96:11664-9. [PMID: 10500234 PMCID: PMC18091 DOI: 10.1073/pnas.96.20.11664] [Citation(s) in RCA: 271] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Sexual reproduction is a salient aspect of plants, and elaborate structures, such as the flowers of angiosperms, have evolved that aid in this process. Within the flower the corresponding sex organs, the anther and the ovule, form the male and female sporangia, the pollen sac and the nucellus, respectively. However, despite their central role for sexual reproduction little is known about the mechanisms that control the establishment of these important structures. Here we present the identification and molecular characterization of the NOZZLE (NZZ) gene in the flowering plant Arabidopsis thaliana. In several nzz mutants the nucellus and the pollen sac fail to form. It indicates that NZZ plays an early and central role in the development of both types of sporangia and that the mechanisms controlling these processes share a crucial factor. In addition, NZZ may have an early function during male and female sporogenesis as well. The evolutionary aspects of these findings are discussed. NZZ encodes a putative protein of unknown function. However, based on sequence analysis we speculate that NZZ is a nuclear protein and possibly a transcription factor.
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Affiliation(s)
- U Schiefthaler
- Institute of Plant Biology, University of Zürich, Zollikerstr. 107, CH-8008 Zürich, Switzerland
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56
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Sieber P, Lindemann A, Boehm M, Seidel G, Herzing U, van der Heusen P, Müller R, Rüger W, Jaenicke R, Rösch P. Overexpression and structural characterization of the phage T4 protein DsbA. Biol Chem 1998; 379:51-8. [PMID: 9504717 DOI: 10.1515/bchm.1998.379.1.51] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The double strand binding protein A (DsbA) of bacteriophage T4 is one of several viral gene products participating in transcriptional regulation. These proteins interact or associate with the host RNA polymerase core enzyme, enabling the enzyme to successively initiate transcription at different classes of viral promoters: early, middle and late. This leads to a temporally controlled expression of the T4 gene products. The DsbA binding site overlaps the late promoter region, and DsbA binding seems to intensify transcription of late genes in vitro, possibly acting as an enhancer protein (Molecular Biology of Phage T4, Karam, 1994). To further investigate the function and structure of DsbA, we overexpressed the protein in E. coli and purified it to homogeneity. Physiological functionality of the recombinant protein was shown by gel retardation experiments and by circular dichroism (CD) spectroscopy. DsbA shows strong bands in the near UV-CD spectra. The far UV-CD spectroscopy analysis shows alpha-helices to be the main secondary structure elements. This is in agreement with secondary structure predictions. A possible helix-turn-helix motif in the center of the protein could be identified. Results from crosslinking and sedimentation analyses show that DsbA forms a dimer in solution. The thermal unfolding curve fits a dimer-two-state-folding-model, and the unfolding temperature was concentration dependent. Therefore, dimerization should supply the main portion of the free energy of stabilization of deltaG0 = 42 kJ/mol.
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Affiliation(s)
- P Sieber
- Lehrstuhl für Struktur und Chemie der Biopolymere, Universität Bayreuth, Germany
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Schaldach J, Sieber P, Diakonov D, Goeke K. Spontaneous annihilation of high-density matter in the electroweak theory. Phys Rev D Part Fields 1996; 54:2814-2828. [PMID: 10020959 DOI: 10.1103/physrevd.54.2814] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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Diakonov D, Polyakov M, Sieber P, Schaldach J, Goeke K. Sphaleron transitions in the minimal standard model and the upper bound for the Higgs boson mass. Phys Rev D Part Fields 1996; 53:3366-3391. [PMID: 10020330 DOI: 10.1103/physrevd.53.3366] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
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Diakonov D, Polyakov M, Sieber P, Schaldach J, Goeke K. Fermion sea along the sphaleron barrier. Phys Rev D Part Fields 1994; 49:6864-6882. [PMID: 10017008 DOI: 10.1103/physrevd.49.6864] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
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60
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Rink H, Liersch M, Sieber P, Meyer F. A large fragment approach to DNA synthesis: total synthesis of a gene for the protease inhibitor eglin c from the leech Hirudo medicinalis and its expression in E. coli. Nucleic Acids Res 1984; 12:6369-87. [PMID: 6382168 PMCID: PMC320083 DOI: 10.1093/nar/12.16.6369] [Citation(s) in RCA: 81] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
A DNA containing the coding sequence for the proteinase inhibitor protein, eglin c, from the leech Hirudo medicinalis has been obtained by enzymatic assembly of chemically synthesized DNA fragments. The synthetic gene consists of a 232 base-pair fragment containing initiation and termination codon signals with restriction enzyme recognition sites conveniently placed for cloning into a plasmid vector. Only six oligonucleotides from 34 to 61 bases in length, sharing pairwise stretches of complementary regions at their 3'-termini, were prepared by phosphotriester solid-phase synthesis. The oligomers were annealed pairwise and converted into double stranded DNA fragments by DNA polymerase I mediated repair synthesis. The fragments were assembled by ligation, and the synthetic gene was expressed in high yield in E. coli under the transcriptional control of the E. coli tryptophan promoter. The expression product was purified to homogeneity and was shown to have similar physicochemical and identical biological properties as the authentic protein isolated from the leech.
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Abstract
Recent data indicates that the free-radical anion superoxide (O2-), an unstable cytotoxic form of oxygen, is implicated in the pathogenesis of ischemic bowel following reperfusion after low flow states. This report evaluates the effect of free radical scavengers on survival in an animal model with bowel ischemia. At laparotomy, the superior mesenteric artery (SMA) of 79 weanling rats (90 g) was occluded for one minute and released. Animals were divided into three experimental groups: group I acted as controls (n = 41), group II, received thiopental 5 mg/kg IV (n = 19), group III, received methohexital 2.5 mg/kg IV (n = 19). At one week animals were evaluated for mortality, mean survival time, evidence of bowel necrosis or perforation, and bowel appearance on scanning electron microscopy (EM). Mortality was 63.5% (26/41) in group I, 19 had necrotic bowel and 7 had gross perforation; 31.6% in group II (6/19) (p less than .05 versus control), with one necrotic bowel and 5 perforations; and 57.9% in group III (11/19) where 7 had necrotic bowel and 4 had perforations (p NS v control). Survival time (mean +/- SD in days) post SMA occlusion was 3.2 +/- 1.9 for group I; 4.0 +/- 1.7 for group II; and 2.5 +/- 2.0 for group III. EM showed mucosal destruction worsened by the duration of reperfusion, decreased by thiopental but not by methohexital. Thiopental, a free radical anion scavenger was cytoprotective in this animal model, as it decreased mortality and the incidence of bowel necrosis and perforation. These data support the thesis that following low flow states bowel ischemia may be related to a reperfusion injury due to the release of toxic free radical anions.
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Weber TR, Dalsing MC, Sawchuck A, Sieber P, Grosfeld JL. The effect of protein deficiency on growth and response of primary and metastatic hepatoma. J Surg Res 1983; 34:395-403. [PMID: 6843109 DOI: 10.1016/0022-4804(83)90088-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Although protein-energy malnutrition is common in the cancer patient, the efficacy of aggressive nutritional therapy is unclear. This study evaluates the effects of protein deficiency on tumor growth, response, and chemotherapy complications in primary and metastatic rat hepatoma. Seventy-two ACI rats (200-250 g) with implanted Morris hepatoma were divided into four groups (N = 18 for each group): 1, regular diet; 2, regular diet plus cyclophosphamide (CPM) (100 mg/kg/ip); 3, protein-free diet; and 4, protein-free diet + CPM. Forty additional rats in similar groups (5-8, ten in each group) underwent intravenous injection of 6 X 10(3) tumor cells to produce pulmonary metastases. Animals were assessed for survival, tumor size, serum albumin, number of pulmonary metastases, and hemorrhagic cystitis at 2 weeks. Survival was 50% in groups 4 and 8, and 100% in the others. Serum albumin was significantly lower in rats on protein free diets (2.59 +/- 0.37 vs 3.35 +/- 0.40 g%, P less than 0.01). Tumor volume was significantly reduced by CPM (26.0 +/- 4.2 cm3 vs 1.2 +/- 0.4 cm3, P less than 0.01). Protein-free diets resulted in lower total body weight, and reduced tumor volume without, but not with CPM (14 +/- 1.6 cm3 P less than 0.05, 1.1 +/- 0.3 cm3, P less than 0.05 vs above controls). CPM reduced the number of pulmonary metastases in regular diet groups (307.2 +/- 108.3 vs 36 +/- 11, P less than 0.01), while protein free diets did not significantly affect metastases, without or with CPM (251.7 +/- 71.4 and 22.3 +/- 12.4, P greater than 0.05 vs controls). Hemorrhagic cystitis was much more common in protein free groups compared to rats on regular diets (55 vs 11%, P less than 0.01). These data indicate that protein deficiency did not affect response to chemotherapy in a primary or metastatic rat hepatoma model. However, protein deficiency results in a significantly increased rate of mortality, weight loss, and hemorrhagic cystitis which may lead to delay or cessation of cancer therapy.
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Abstract
Somatostatin (SRIF) was applied microiontophoretically to neurons in the frontal and parietal neocortex, the hippocampus and the striatum of rats anaesthetized with either urethane or chloral hydrate. Qualitatively identical results were obtained under both anaesthetic conditions. In urethane-treated rats SRIF elicited a dose-dependent increase of the firing rate of 74% of the neurons studied in the frontal cortex and of 46% of the neurons studied in the parietal cortex. All cortical cells identified as pyramidal cells were excited. In the hippocampus SRIF provoked excitatory responses in two thirds of all neurons. Six out of the nine cells identified as pyramidal cells were excited by SRIF. In the striatum 80% of all neurons were excited. Following repeated exposure of central neurons to SRIF, the magnitude of the excitatory response gradually diminished, indicating desensitisation. SRIF in concentrations ranging from 10(-8) to 10(-4) M did not interfere with the binding of (3H)-muscimol to GABA receptor sites. The release of GABA from synapses preloaded with (3H-GABA) was not influenced by SRIF in the concentration range from 10(-6) to 10(-4) M. These results indicated that SRIF does not evoke the excitatory responses through attenuation of GABA-mediated inhibition. In conclusion, the findings support the hypothesis that somatostatin may function as a neurotransmitter in the central nervous system.
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Märki F, de Gasparo M, Eisler K, Kamber B, Riniker B, Rittel W, Sieber P. Synthesis and biological activity of seventeen analogues of human insulin. Hoppe Seylers Z Physiol Chem 1979; 360:1619-32. [PMID: 511097 DOI: 10.1515/bchm2.1979.360.2.1619] [Citation(s) in RCA: 38] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
We synthesized seventeen analogues of human insulin, applying the principle of stepwise, selective formation of the disulphide bonds. Most of these analogues only differ from human insulin in the replacement of a single amino acid in positions 2, 5, 6, 7, 8 and 11 of the A chain and 5, 7, 13 and 16 of the B-chain. The influence of these modifications on the physicochemical properties of the analogues is discussed. Eight analogues could be crystallized. All the analogues produce the same biological effects as insulin, but differ markedly in their potency. In isolated fat cells in vitro, [HisA8]insulin showed a relative potency of 2.46 in stimulating glucose oxidation (human insulin = 1), whereas [D-CysA6,A11]insulin had a potency of only 0.00027. Very low potency was observed when IleA2 or the half-cystines A6, A7, A11 or B7 were modified. Replacement of the invariant GlnA5 by alanine only reduced potency slightly. All the analogues are full agonists. The effects of the analogues on glucose oxidation and lipolysis are correlated, supporting the view that they are mediated by a common receptor on the fat-cell membrane. Hypoglycaemic potencies in the rat were similar to potencies in vitro. As expected, no correlation was demonstrable between antiserum binding--measured in the radioimmunoassay--and biological activity. Several results of this investigation are difficult to reconcile with the current view regarding the structure-activity relationship of insulin which appears to require further refinement.
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Abstract
The effects of two [D-Cys14]-analogues of somatostatin on basal plasma levels of glucagon, insulin and glucose were determined in unanaesthetized rats to re-examine a glucagon-selective action of these peptides which has been claimed by others. Somatostatin, [D-Cys14]-somatostatin and [D-Trp8, D-Cys14]-somatostatin caused a short-lasting, dose-dependent decrease of plasma glucagon and insulin but they had no significant influence on plasma glucose. Glucagon and insulin reached the nadir 2 min after intravenous injection of the peptides (dose range 1--10 micrograms/kg) or 5 min after subcutaneous administration (30 and 300 micrograms/kg). At the nadir, insulin was decreased to a greater extent than glucagon and the effecer the nadir and at high doses, the time-course of some effects of the analogues on either glucagon or insulin differed from that of somatostatin. Thus, these [D-Cys14]-analogues may show partial kinetic dissociation of effects on glucagon and insulin but they are not truly selective inhibitors of glucagon release.
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Heidbreder E, Sieber P, Heidland A. [The effect of mainly alpha-adrenergic drugs, indirect sympathomimetrics and dopamine on exocrine pancreatic function. Studies in the isolated cat pancreas (author's transl)]. Res Exp Med (Berl) 1978; 172:97-108. [PMID: 25465 DOI: 10.1007/bf01851069] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The influence of mainly alpha-adrenergic drugs (noradrenaline, adrenaline, phenylephrine), indirect sympathomimetics (ephedrine, tyramin) and dopamine on the exocrine pancreatic function of the isolated perfused organ of cats was studied. The injection of noradrenaline and adrenaline induced simultaneously a rapid depression of flow rate and an increase of perfusion pressure. Phenylephrine, indirect sympathomimetic drugs and dopamine did not change the perfusion pressure and the hydrelatic function (flow rate, secretion of chloride and total calcium). The protein and enzyme secretion was enhanced both in normal animals and cats pretreated by reserpine or 6-hydroxydopamine. The pancreatic protein secretion was inhibited by alpha-adrenolytic as well as beta-adrenolytic substances, tetracain and atropine. It is concluded, that mainly alpha-adrenergic drugs stimulate the pancreatic enzyme secretion in a cholinergic manner.
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Sieber P, Eisler K, Kamber B, Riniker B, Rittel W, Märki F, de Gasparo M. Synthesis and biological activity of two disulphide bond isomers of human insulin: [A7-A11,A6-B7-cystine]- and [A6-A7,A11-B7-cystine]insulin (human). Hoppe Seylers Z Physiol Chem 1978; 359:113-23. [PMID: 627397 DOI: 10.1515/bchm.1978.359.1.113] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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68
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Heidbreder E, Sieber P, Heidland A. [The effect of sympathomimetric drugs on exocrine pancreatic function. Studies in the isolated cat pancreas (author's transl)]. Res Exp Med (Berl) 1977; 171:79-82. [PMID: 20653 DOI: 10.1007/bf01851591] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
This study reports on effects of beta-sympathomimetic drugs on the exocrine function of the isolated cat pancreas. The injection of these drugs resulted in an increase of pancreatic protein and enzyme secretion, the excretion of calcium into the juice and the rate of volume output were not changed. The enzyme secretion was inhibited by different adrenolytic drugs (phenoxybenzamine, practolol, butoxamine), by tetracain, hemicholinium, and atropine. The pancreatic function of cats pretreated by reserpine or 6-hydroxydopamine was not altered. It is concluded, that beta-sympathomimetic drugs influence the pancreatic protein and enzyme secretion in a cholinergic way. These results are consistent with those of other investigators showing a suppressibility of the isoproterenol-induced pancreatic amylase secretion by atropine.
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69
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McMartin C, Purdon GE, Schenkel L, Desaulles PA, Maier R, Brugger M, Rittel W, Sieber P. Differences between in-vitro and in-vivo potencies of corticotrophins: an interpretation in terms of metabolic stability. J Endocrinol 1977; 73:79-89. [PMID: 192825 DOI: 10.1677/joe.0.0730079] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Relative activities of a series of corticotrophin analogues have been measured by means of five different bioassays using the rat. Similarities in the relative potencies of various ACTH analogues determined using lipolysis or steroidogenesis in vivo and for the lipolytic and steroidogenic responses of fat pads and adrenal slices in vitro emerged and support the concept of a close structural relationship between the ACTH receptors in adipose and adrenal tissues in the rat. Potencies based on the steroidogenic response of isolated adrenal cells, adrenal slices or in-vivo experiments differed markedly from each other. Inactivation of peptides did not occur in the isolated cell assay, so it is likely that this assay estimates potency at the receptor level. A number of arguments suggest that the difference between the isolated cell assay and the other steroidogenic assays lies solely in the effects of peptide inactivation in the latter, and this allows the relative metabolic stabilities for the peptide analogues in these assays to be calculated. In this way it can be shown that: (1) Replacement of L-Ser by D-Ser in amino acid position 1 markedly increases the metabolic stability of the peptide and has only a slight effect on receptor properties. (2) Shortening at the NH2-terminus reduces the activity of peptides at the receptor level by several orders of magnitude, but increases their relative metabolic stability. (3) Introduction of amide groups at the CO2H-terminus markedly increases receptor potency of (1-16), (1-17) and (1-18) ACTH without affecting their metabolic stability in vivo. However, amidation of the CO2H-terminus does have a large effect on metabolic stability in the adrenal slice assay. (4) Replacement of Arg by Lys in positions 17 and 18 of (1-18) ACTH increases potency at the receptor level (adrenal cells) but has little effect on metabolic stability. The comparison of potencies obtained in the various assays, therefore, throws light on the significance of each assay. In addition, the effects of structural modification of analogues can be separately evaluated with respect to the metabolic stability of a peptide and its potency at the receptor level.
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Sieber P, Kamber B, Hartmann A, Jöhl A, Riniker B, Rittel W. [Total synthesis of human insulin. IV. Description of the final steps (author's transl)]. Helv Chim Acta 1977; 60:27-37. [PMID: 838597 DOI: 10.1002/hlca.19770600105] [Citation(s) in RCA: 92] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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71
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Kamber B, Riniker B, Sieber P, Rittel W. [Synthesis of human insulin. III. Preparation of the A(14-21) - B(17-30) fragment (author's transl)]. Helv Chim Acta 1976; 59:2830-40. [PMID: 1017975 DOI: 10.1002/hlca.19760590821] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
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72
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Sieber P, Kamber B, Eisler K, Hartmann A, Riniker B, Rittel W. [Synthesis of human insulin. II. preparation of the a(1-13) fragment (author's transl)]. Helv Chim Acta 1976; 59:1489-97. [PMID: 931751 DOI: 10.1002/hlca.19760590510] [Citation(s) in RCA: 31] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
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73
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Rittel W, Maier R, Brugger M, Kamber B, Riniker B, Sieber P. [Structure-activity relationship of human calcitonin. III. Biological activity of synthetic analogues with shortened or terminally modified peptide chains (author's transl)]. Experientia 1976; 32:246-8. [PMID: 1269626 DOI: 10.1007/bf01937791] [Citation(s) in RCA: 48] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Assays of 8 synthetic analogues of human calcitonin in rats showed that their hypocalcaemic activity was drastically reduced by deletion of the C-terminal amide group, chain-shortening or opening of the disulphide ring, but unaffected or enhanced by modification of the N-terminal amino group.
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74
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Heidbreder E, Sieber P, Heidland A. [Exocrine pancreatic function and calcium balance. Experimental studies of the effect of parathyroid hormone, vitamin D3, 25-hydroxycholecalciferol, dihydrotachysterin and thyrocalcitonin (author's transl)]. Res Exp Med (Berl) 1975; 166:147-63. [PMID: 173000 DOI: 10.1007/bf01851181] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The effect of the acute elevation of extracellular calcium concentration, of vitamin D3, 25-hydroxycholecalciferol, dihydrotachysterin, parathyroid hormone and of thyrocalcitonin on the exocrine function of the perfused cat pancreas was studied. Elevation of the perfusate calcium concentration resulted in an initial increase in the enzyme and, occasionally, calcium concentration of the pancreatic juice, the flow rate and the secretion of magnesium and chloride were not very much altered. The application of vitamin D3 and 25-hydroxycholecalciferol elevated the stimulated (by acetylcholine or cholecystokinin-pancreocymin) protein and enzyme output (lipase, alpha-amylase). Parathyroid hormone and, especially, thyreocalcitonin inhibited the stimulated protein and enzyme secretion, volume and rate of the electrolyte secretion were not changed. In states of calcium excess the stimulated protein output was decreased by both vitamin D3 and parathyroid hormone.
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Schenkel-Hulliger L, Maier R, Barthe PL, Desaulles PA, Jarret A, Riniker B, Rittel W, Sieber P. Biological activity of synthetic human corticotropin with revised amino acid sequence. Acta Endocrinol (Copenh) 1974; 75:24-32. [PMID: 4363844 DOI: 10.1530/acta.0.0750024] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
ABSTRACT
The corticotrophic, melanotrophic and lipolytic activity of synthetic human corticotrophin of revised structure has been evaluated and compared with that of synthetic porcine ACTH (uncorrected structure). The amino acid sequence of the two peptides differs at 3 sites in the 25 to 31 region. The two peptides exihibit identical biological activities in in vitro and in vivo test systems in the rat.
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Sieber P, Kamber B, Hartmann A, Jöhl A, Riniker B, Rittel W. [Total synthesis of human insulin under directed formation of the disulfide bonds]. Helv Chim Acta 1974; 57:2617-21. [PMID: 4443293 DOI: 10.1002/hlca.19740570839] [Citation(s) in RCA: 110] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
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78
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Andreatta RH, Hartmann A, Jöhl A, Kamber B, Maier R, Riniker B, Rittel W, Sieber P. [Synthesis of sequence 1-34 of human parathyroid hormone]. Helv Chim Acta 1973; 56:470-3. [PMID: 4721748 DOI: 10.1002/hlca.19730560139] [Citation(s) in RCA: 29] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
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79
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Riniker B, Sieber P, Rittel W, Zuber H. Revised amino-acid sequences for porcine and human adrenocorticotrophic hormone. Nat New Biol 1972; 235:114-5. [PMID: 4334191 DOI: 10.1038/newbio235114b0] [Citation(s) in RCA: 76] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
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81
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Kamber B, Brückner H, Riniker B, Sieber P, Rittel W. [Human calcitonin. V. Synthesis and characterization of the protected calcitonin M-(1-10)-decapeptide]. Helv Chim Acta 1970; 53:556-64. [PMID: 5425934 DOI: 10.1002/hlca.19700530312] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
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83
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Sieber P, Iselin B. [On the synthesis of 2-(p-biphenyl)-isopropyloxycarbonyl-(Bpoc)-aminoacids and the decomposition of aralkyl-phenyl carbonates]. Helv Chim Acta 1969; 52:1525-31. [PMID: 5820777 DOI: 10.1002/hlca.19690520613] [Citation(s) in RCA: 29] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
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85
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Sieber P, Iselin B. [Peptide synthesis under application of the 2-(p-diphenyl)-isopropyloxycarbonyn (Dpoc)-amino protection groups]. Helv Chim Acta 1968; 51:622-32. [PMID: 5683980 DOI: 10.1002/hlca.660510405] [Citation(s) in RCA: 129] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
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90
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92
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Schwyzer R, Rittel W, Sieber P, Kappeler H, Zuber H. Synthese vonL-Arginyl-L-propyl-L-propyl-glycyl-L-phenylalanyl-L-seryl-L-phenylalanyl-L-arginin (Bradykinin?). Vorl�ufige Mitteilung. Helv Chim Acta 1960. [DOI: 10.1002/hlca.19600430423] [Citation(s) in RCA: 27] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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93
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Burckhardt V, Kündig W, Sieber P. Über die Herstellung von N-Methyl-N-[1,2,3,4-tetra-hydro-naphtyl-(2)]-β-aminopropionsäure-(2′-oxy-isopropyl)-amid und N-Methyl-N-[1,2,3,4-tetrahydro-naphtyl-(2)]-β-amino-propionsäure-(2′-amino-isopropyl)-ester-dihydrochlorid. Helv Chim Acta 1952. [DOI: 10.1002/hlca.19520350502] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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