| 3459111 |
The biodistribution of 67Ga-labelled N-hydroxyamino acid derivatives in tumour-bearing rats |
10.1097/00006231-198601000-00007. |
Nucl Med Commun |
The biodistribution of 67Ga-labelled N-hydroxyamino acid derivatives in tumour-bearing rats
Abstract
- The biodistribution of 67Ga-labelled complexes of some mono- and di-N-hydroxyamino acid derivatives and of two siderophores (trihydroxamates) were evaluated in Rhabdomyosarcoma-bearing rats. It was found that the mono- and dihydroxamates could not enhance the tumour-localizing properties of 67Ga-citrate, while the 67Ga-labelled trihydroxamates showed very rapid urinary excretion.
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| 3494014 |
Protein sequence of endothelial glycoprotein IIIa derived from a cDNA clone. Identity with platelet glycoprotein IIIa and similarity to 'integrin'. |
10.1016/s0021-9258(18)61290-6 |
J. Biol. Chem. |
Protein sequence of endothelial glycoprotein IIIa derived from a cDNA clone. Identity with platelet glycoprotein IIIa and similarity to 'integrin'.
Abstract
- Platelet membrane glycoprotein (GP) IIIa forms a Ca2+-dependent heterodimer complex with GP IIb. The GP IIb-IIIa complex constitutes the fibrinogen and fibronectin receptor on stimulated platelets. A biochemically and immunologically similar membrane glycoprotein complex is present on endothelial cells. A human umbilical vein endothelial cell cDNA library was screened using oligonucleotide probes designed from peptide sequences obtained from platelet GP IIIa. A cDNA clone was sequenced and found to encode a protein of 84.5 kDa. The translated endothelial cDNA contained five sequences that corresponded to peptide sequences in platelet GP IIIa, including the amino-terminal 19 residues. Thus, the endothelial and platelet forms of GP IIIa are apparently identical. Glycoprotein IIIa consists of a long amino-terminal extracellular domain with several potential N-linked glycosylation sites and four cysteine-rich tandem repeats, a 29-residue hydrophobic transmembrane segment, and a short carboxyl-terminal cytoplasmic domain. Glycoprotein IIIa has a 47% amino acid sequence homology to "integrin," a fibronectin receptor from chicken embryo fibroblasts. This homology suggests that GP IIIa is a member of a family of cell-surface adhesion receptors.
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| 3509344 |
Degradation of a tetragastrin analogue by a membrane fraction from rat gastric mucosa |
None |
Drug Des Deliv |
Degradation of a tetragastrin analogue by a membrane fraction from rat gastric mucosa
Abstract
- Our previous work on the effect of modification of peptide bonds in gastrin-like peptides led us to speculate that cleavage of the bond between the Met and Asp residues occurs in gastric mucosal membranes, and that this cleavage may have functional significance. In agreement with this speculation, we now show that the tetragastrin analogue BOC-Trp-Leu-Asp-Phe-NH2 (1) is degraded by a membrane fraction from rat gastric mucosa, and that the main products are BOC-Trp-Leu and Asp-Phe-NH2. Pseudo-peptide analogues in which the peptide bonds are replaced by CH2NH had differing stabilities; BOC-Trp-Leu-Asp-psi (CH2NH)-Phe NH2 (4) and BOC-Trp-Leu-psi(CH2NH)-Asp-Phe-NH2 (3) were stable under the incubation conditions, whereas BOC-Trp-psi(CH2NH)-Leu-Asp-Phe-NH2 (2) was degraded. The peptide and pseudo-peptide which were degraded (1 and 2) have been shown to stimulate gastric acid secretion in rats, in vivo, whereas 3 and 4 (which were not hydrolyzed) were inactive in stimulating gastric acid secretion and were found to antagonize the action of gastrin.
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| 3525401 |
Radiometric evaluation of antibacterial activity of bouvardin (NSC 259968) on Escherichia coli and Staphylococcus aureus |
None |
Indian J Exp Biol |
Radiometric evaluation of antibacterial activity of bouvardin (NSC 259968) on Escherichia coli and Staphylococcus aureus
Abstract
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| 3542546 |
Plasmodium falciparum: inhibition in vitro with lactoferrin, desferriferrithiocin, and desferricrocin |
10.1016/0014-4894(87)90072-5. |
Exp Parasitol |
Plasmodium falciparum: inhibition in vitro with lactoferrin, desferriferrithiocin, and desferricrocin
Abstract
- The microbial iron chelators desferriferrithiocin and desferricrocin as well as human lactoferrin were tested in vitro against Plasmodium falciparum. The microbial chelators inhibit the growth of P. falciparum in a dose dependent way. Parasite multiplication is stopped at 25-30 microM desferriferrithiocin, whereas 60-90 microM desferricrocin are needed to exhibit the same effect. After iron saturation, the microbial chelators are ineffective. Human lactoferrin (30 microM), both iron free and iron saturated, inhibits P. falciparum. A 3-day preincubation of host erythrocytes with iron free and iron saturated lactoferrin prior to infection enhances this effect, which is therefore attributed to lactoferrin bound iron. It has been suggested that the lactoferrin/iron complex generates oxygen free radicals, which may cause membrane damage of both erythrocyte and parasite. This process can be considered to lead to growth inhibition of the parasite.
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| 3567158 |
Prothrombin Tokushima, a replacement of arginine-418 by tryptophan that impairs the fibrinogen clotting activity of derived thrombin Tokushima |
10.1021/bi00378a020. |
Biochemistry |
Prothrombin Tokushima, a replacement of arginine-418 by tryptophan that impairs the fibrinogen clotting activity of derived thrombin Tokushima
Abstract
- Structural studies on a hereditarily abnormal prothrombin, prothrombin Tokushima, have been performed to identify the difference responsible for its reduced fibrinogen clotting activity upon conversion to thrombin. The prothrombin sample used was from a heterozygote but contained exclusively a defective prothrombin molecule, since the patient was heterozygous for both dysprothrombinemia and hypoprothrombinemia. Amino acid sequence analysis of a peptide isolated from a lysyl endopeptidase digest of the abnormal thrombin indicated that Arg-418 (equivalent to Asn-101 in the chymotrypsin numbering system) had been replaced by Trp. This amino acid substitution can result from a single nucleotide change in the codon for Arg-418 (CGG----TGG). The Arg----Trp replacement found in the thrombin portion of prothrombin Tokushima appears to reduce its interaction with various substrates including fibrinogen and platelet receptors and accounts for the recurrent bleeding episode observed in the propositus.
|
| 3570979 |
Mulundocandin, a new lipopeptide antibiotic. I. Taxonomy, fermentation, isolation and characterization |
10.7164/antibiotics.40.275. |
J Antibiot (Tokyo) |
Mulundocandin, a new lipopeptide antibiotic. I. Taxonomy, fermentation, isolation and characterization
Abstract
- Mulundocandin, a new lipopeptide antibiotic, was isolated from the culture broth of a strain of Aspergillus sydowi No. Y-30462. The antibiotic, obtained as a colorless amorphous powder having the molecular formula C48H77N7O16, is an antifungal antibiotic active against yeasts and filamentous fungi.
|
| 3570980 |
Mulundocandin, a new lipopeptide antibiotic. II. Structure elucidation |
10.7164/antibiotics.40.281. |
J Antibiot (Tokyo) |
Mulundocandin, a new lipopeptide antibiotic. II. Structure elucidation
Abstract
- The structure of a new antifungal antibiotic, mulundocandin, C48H77N7O16, was elucidated by high field NMR experiments e.g., homo- and heteronuclear correlation spectra, distortionless enhancement by polarization transfer (DEPT) spectra as well as nuclear Overhauser effect. The compound is a lipopeptide antibiotic belonging to the echinocandin class.
|
| 3580176 |
Effect of phalloidin and viroisin on Acanthamoeba castellanii after permeabilization of the cell |
10.1139/o87-034. |
Biochem Cell Biol |
Effect of phalloidin and viroisin on Acanthamoeba castellanii after permeabilization of the cell
Abstract
- We have developed a new technique for the permeabilization of the membrane of Acanthamoeba castellanii. This technique involves the use of digitonin which alters neither the morphology nor the motility of the cell, but favours the penetration of phalloidin and viroisin. Treatment of permeabilized cells with phalloidin or viroisin induces, in the cortex of the cell, an intensive proliferation of filaments which have been identified as actin. This cortical filamentous layer detaches from the membrane and slowly contracts, acting as a fine mesh sieve which concentrates the organelles in the middle of the cell, causing therefore the formation of a central granuloplasm and a cortical hyaloplasm. During this process, cell motility is irreversibly lost. The results indicate that extensive proliferation and reorganization of actin filaments cannot support cell motility and they are discussed in terms of a general understanding of amoeboid movement.
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| 3583913 |
Isolation and characterization of new iturins: iturin D and iturin E |
10.7164/antibiotics.40.437. |
J Antibiot (Tokyo) |
Isolation and characterization of new iturins: iturin D and iturin E
Abstract
- Two new antibiotics, iturin D and iturin E, were isolated from a strain of Bacillus subtilis producing iturin A. These compounds belong to the iturin group, the acid hydrolysates contained alpha-amino acids Asp3, Glu1, Pro1, Ser1, Tyr1, and a mixture of n-C14, iso-C15, anteiso-C15, iso-C16 and n-C16 beta-amino acids. They differ from iturin A by the presence of a free carboxyl group in iturin D and a carboxymethyl group in iturin E.
|
| 3583919 |
OF4949, new inhibitors of aminopeptidase B. IV. Effects of OF4949 and its derivatives on enzyme systems |
10.7164/antibiotics.40.512. |
J Antibiot (Tokyo) |
OF4949, new inhibitors of aminopeptidase B. IV. Effects of OF4949 and its derivatives on enzyme systems
Abstract
- OF4949-I and II inhibited aminopeptidase B from Ehrlich ascites carcinoma in a competitive way and the Ki value for both against L-arginine-beta-naphthylamide was 8 X 10(-9) M. Inhibition by I and II of various exopeptidases and endopeptidases was examined. OF4949-I and II both strongly inhibited leucine aminopeptidase and enkephalin-degrading aminopeptidase; I also inhibited enkephalinase B. The inhibitory effects of various derivatives of I and II on aminopeptidase B activity, showed that the terminal amino and carboxamide groups are essential for activity.
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| 3583920 |
OF4949, new inhibitors of aminopeptidase B. V. Effect on the murine immune system |
10.7164/antibiotics.40.519. |
J Antibiot (Tokyo) |
OF4949, new inhibitors of aminopeptidase B. V. Effect on the murine immune system
Abstract
- OF4949-I inhibited the growth of the solid form of IMC carcinoma and protected against pulmonary metastases of Lewis lung carcinoma. It also augmented the cytostatic activity of mouse peritoneal macrophages, the natural killer activity, and the antibody-dependent cell-mediated cytotoxicity of mouse spleen cells. This substance was not cytotoxic to cultured tumor or normal cells even at high concentrations. These results suggest that a cell-mediated immune response stimulated by this compound might account for its antitumor activity.
|
| 3596898 |
17O and 14N n.m.r. studies of the Co (II) interaction with cyclo(Ala*-Ala) in aqueous solution |
10.1111/j.1399-3011.1987.tb02267.x. |
Int J Pept Protein Res |
17O and 14N n.m.r. studies of the Co (II) interaction with cyclo(Ala*-Ala) in aqueous solution
Abstract
- The complexation of cyclo(Ala*-Ala) with the cobaltous ions in aqueous solution was investigated by 17O and 14N n.m.r. spectroscopy. The 17O and 14N transverse relaxation time (T2p) and chemical shift (delta omega a) of cyclo(Ala*-Ala) were measured as a function of the temperature at pH = 7.03 +/- 0.02, and pH = 6.45 +/- 0.02, and as a function of pH at room temperature. No effects of pH on the transverse relaxation time and chemical shift were observed. Complementary 17O studies of the solvent water molecules were also carried out. The hyperfine coupling constant and the entropy and enthalpy of activation for the exchange of cyclo(Ala*-Ala) and water molecules between the coordinated and noncoordinated states were determined by least-square fit of theoretical equation for the chemical shift delta omega a to experimental data. The hyperfine coupling constant of the peptide bound oxygen was determined to be (-1.6 +/- 0.1) X 10(5) Hz and the entropy and enthalpy (32.0 +/- 3.0) kJ/mol and (-12.0 +/- 1.0) e.u, respectively. Information obtained from 17O n.m.r. study allows some inferences concerning the probable coordination sphere of the cobaltous ion. There are three types of complexes: Co(H2O)6(2+), CoL X 5H2O and CoL2 X 4H2O, with relative concentrations 19.9%, 2.9%, and 77.2%, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)
|
| 3610474 |
Fourth polymorph of Phe4 Val6 antamanide (pentahydrate) |
None |
Int J Pept Protein Res |
Fourth polymorph of Phe4 Val6 antamanide (pentahydrate)
Abstract
- The cyclic decapeptide antamanide and the synthetic, biologically active analog Phe4 Val6antamanide (cyclicValProProPhePhe2) crystallize in various crystal forms as a function of the solvent. The present crystalline polymorph obtained from acetone/water (also from ethanol/water and DMSO/water) crystallizes in space group P2(1)2(1)2(1) with a = 20.194 (30) A, b = 21.118 (31) A, c = 16,132 (25) A and four molecules of peptide in the unit cell. There are five cocrystallized water molecules per peptide molecule, of which four water molecules are intrinsic to the peptide molecule. Although the molecular packing is entirely different in each of the polymorphs, the conformation of the peptide molecule, including the intrinsic water molecules, is very similar in all the polymorphs.
|
| 3631886 |
Antitumor activity and toxicity in mice of RA-700, a cyclic hexapeptide |
None |
Anticancer Res |
Antitumor activity and toxicity in mice of RA-700, a cyclic hexapeptide
Abstract
- The antitumor activity of RA-700, a cyclic hexapeptide isolated from Rubia Cordifolia, was evaluated in comparison with deoxy-bouvardin and vincristine (VCR). As regards the proliferation of L1210 cultured cells, the cytotoxicity of RA-700 was similar to that of VCR but superior to that of deoxy-bouvardin. The IC50 value of RA-700 was 0.05 mcg/ml under our experimental conditions. RA-700 inhibited the incorporation of 14C-leucine at a concentration at which no effects were observed on the incorporation of 3H-thymidine and 3H-uridine in L1210 culture cells in vitro. The antitumor activity of RA-700 was similar to that of deoxy-bouvardin and VCR against P388 leukemia. Daily treatment with RA-700 at an optimal dose resulted in 118% ILS. As with deoxy-bouvardin and VCR, the therapeutic efficacy of RA-700 depends on the time schedule. RA-700 showed marginal activity against L1210 leukemia (50% ILS), similar to that of deoxy-bouvardin but inferior to that of VCR. RA-700 inhibited Lewis tumor growth in the early stage after tumor implantation, whereas deoxy-bouvardin and VCR did not. As regards toxicity, a slight reduction of peripheral WBC counts was observed with the drug, but no reduction of RBC and platelet counts. BUN, creatinine, GPT and GOT levels in plasma did not change with the administration of the drug.
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