Search Results - (Author, Cooperation:T. Zimmerman)

2011-03-25

Nature Publishing Group (NPG)

0028-0836

1476-4687

Biology

Chemistry and Pharmacology

Medicine

Natural Sciences in General

Physics

Amino Acid Sequence ; Blood Coagulation/genetics ; CpG Islands/genetics ; DNA Mutational Analysis ; DNA Repair/genetics ; Exons/genetics ; Exosome Multienzyme Ribonuclease Complex ; Genome, Human/*genetics ; Genomics ; Histones/metabolism ; Homeodomain Proteins/genetics ; Homeostasis/genetics ; Humans ; Methylation ; Models, Molecular ; Molecular Sequence Data ; Multiple Myeloma/drug therapy/enzymology/*genetics/metabolism ; Mutation/*genetics ; NF-kappa B/metabolism ; Oncogenes/genetics ; Open Reading Frames/genetics ; Protein Biosynthesis/genetics ; Protein Conformation ; Proto-Oncogene Proteins B-raf/antagonists & inhibitors/genetics/metabolism ; RNA Processing, Post-Transcriptional/genetics ; Ribonucleases/chemistry/genetics ; Signal Transduction/genetics ; Transcription, Genetic/genetics

1471-4159

Blackwell Publishing Journal Backfiles 1879-2005

Medicine

Abstract: Selective modification of the tetrahydrobiopterin levels in cultured chromaffin cells were followed by changes in the rate of tyrosine hydroxylation. Addition of sepiapterin, an intermediate on the salvage pathway for tetrahydrobiopterin synthesis, rapidly increased intracellular levels of tetrahydrobiopterin and elevated the rate of tyrosine hydroxylation in the intact cell. Tyrosine hydroxylation was also enhanced when tetrahydrobiopterin was directly added to the incubation medium of intact cells. When the cultured chromaffin cells were treated for 72 h with N-acetylserotonin, an inhibitor of sepiapterin reductase, tetrahydrobiopterin content and the rate of tyrosine hydroxylation were decreased. Addition of sepiapterin or N-acetylserotonin had no consistent effect on total extractable tyrosine hydroxylase activity or on catecholamine content in the cultured chromaffin cells. Three-day treatment of chromaffin cell cultures with compounds that increase levels of cyclic AMP (forskolin, cholera toxin, theophylline, dibutyryl- and 8-bromo cyclic AMP) increased total extractable tyrosine hydroxylase activity and GTP-cyclohydrolase, the rate-limiting enzyme in the biosynthesis of tetrahydrobiopterin. Tetrahydrobiopterin levels and intact cell tyrosine hydroxylation were markedly increased after 8-bromo cyclic AMP. The increase in GTP-cyclohydrolase and tetrahydrobiopterin induced by 8-bromo cyclic AMP was blocked by the protein synthesis inhibitor cycloheximide. Agents that deplete cellular catecholamines (reserpine, tetrabenazine, and brocresine) increased both total tyrosine hydroxylase and GTP-cyclohydrolase activities, although treating the cultures with reserpine or tetrabenazine resulted in no change in cellular levels of cyclic AMP. Brocresine and tetrabenazine increased tetrahydrobiopterin levels, but the addition of reserpine to the cultures decreased catecholamine and tetrahydrobiopterin content and resulted in a decreased rate of intact cell tyrosine hydroxylation in spite of the increased activity of the total extractable enzyme. These data indicate that in cultured chromaffin cells GTP-cyclohydrolase activity like tyrosine hydroxylase activity is regulated by both cyclic AMP-dependent and cyclic AMP-independent mechanisms and that the intracellular level of tetrahydrobiopterin is one of the many factors that control the rate of tyrosine hydroxylation.

Electronic Resource

1471-4159

Blackwell Publishing Journal Backfiles 1879-2005

Medicine

Rat brain myelin showed substantial activity of 5′-nucleotidase. The specific activity in myelin was enriched two- to threefold over that in rat brain homogenates, and the total activity in myelin accounted for approximately 24% of the activity in the homogenates. The 5′-nucleotidase in the homogenates and in isolated myelin had optimum activity at pH 7.5-9.0, was stimulated by Mg2+ and Mn2+, and was inhibited by Co2+, Zn2+, EDTA, and EGTA. 5′-AMP, 5′-UMP, and 5′-CMP were the preferred substrates, and 5′-GMP was hydrolyzed at approximately one-half the rate of the other mononucleotides. The very low rates of cleavage of β-glycerophosphate and 2′-AMP ruled out any significant contribution of nonspecific phosphatase to the observed 5′-nucleotidase activity in myelin. The 5′-nucleotidase was inhibited by concanavalin A and was protected by α-methyl-d-mannoside against inhibition by that lectin, suggesting that this enzyme in the CNS is a glycoprotein. It is concluded from these data, and from histochemical observations made in other laboratories, that the myelin sheath is one major locus of 5′-nucleotidase in the rat brain.

Electronic Resource

0168-9002

Elsevier Journal Backfiles on ScienceDirect 1907 - 2002

Physics

Electronic Resource

1420-908X

Springer Online Journal Archives 1860-2000

Medicine

Abstract We have studied the effect of taxol on two N-formyl-methionyl-leucyl-phenylalanine (FMLP)-induced neutrophil functions and the possible mechanism by which it inhibits these functions. Taxol inhibited FMLP-induced human neutrophil polarization (a characteristic change in neutrophil shape in response to a chemotactic stimulus) and H2O2 generation. Taxol also decreased the specific binding of [3H]FMLP to human neutrophils at 4°C. The decreased binding of FMLP to its receptor may be responsible for the inhibition by taxol of FMLP-induced polarization and H2O2 generation.

Electronic Resource

1420-908X

Springer Online Journal Archives 1860-2000

Medicine

Abstract Treatment of cultured human umbilical vein endothelial cells (HUVE) with tumor necrosis factor alpha (TNF-α) increases their capacity to adhere human neutrophils. We have found that 3-deazaadenosine (c3Ado), when added in conjunction with TNF-α, inhibited this increase in neutrophil adherence. This activity of c3Ado was potentiated by the addition ofl-homocysteine thiolactone (Hcy). The ability of c3Ado to inhibit neutrophil adherence to HUVE may contribute to the anti-inflammatory activity of this nucleoside analogue.

Electronic Resource

1573-9171

Springer Online Journal Archives 1860-2000

Chemistry and Pharmacology

Abstract Catalysts of 4.5% Co- 0.1% Rh- 5:10% Cu/TiO 2 display high activity in the synthesis from CO and H2 of a mixture of hydrocarbons and alcohols at 250–300°C and pressures of 0.1–6.0 MPa; these catalysts are more selective than traditional Co catalysts with respect to alcohol formation.

Electronic Resource