CYP3A4*16 and CYP3A4*18 alleles found in East Asians exhibit differential catalytic activities for seven CYP3A4 substrate drugs.

CYP3A4, the major form of cytochrome P450 (P450) expressed in the adult human liver, is involved in the metabolism of approximately 50% of commonly prescribed drugs. Several genetic polymorphisms in CYP3A4 are known to affect its catalytic activity and to contribute in part to interindividual differences in the pharmacokinetics and pharmacodynamics of CYP3A4 substrate drugs. In this study, catalytic activities of the two alleles found in East Asians, CYP3A4*16 (T185S) and CYP3A4*18 (L293P), were assessed using the following seven substrates: midazolam, carbamazepine, atorvastatin, paclitaxel, docetaxel, irinotecan, and terfenadine.

Substrate-dependent functional alterations of seven CYP2C9 variants found in Japanese subjects.

CYP2C9 is a polymorphic enzyme that metabolizes a number of clinically important drugs. In this study, catalytic activities of seven alleles found in Japanese individuals, CYP2C9*3 (I359L), *13 (L90P), *26 (T130R), *28 (Q214L), *30 (A477T), *33 (R132Q), and *34 (R335Q), were assessed using three substrates (diclofenac, losartan, and glimepiride). When expressed in a baculovirus-insect cell system, the holo and total (apo and holo) CYP2C9 protein expression levels were similar among the wild type (CYP2C9.

P-selectin glycoprotein ligand-1 mediates L-selectin-independent leukocyte rolling in high endothelial venules of peripheral lymph nodes.

Lymphocyte homing to peripheral lymph nodes (LNs) requires L-selectin. Previous studies, however, suggest that there are L-selectin-independent mechanisms of lymphocyte homing. P-selectin glycoprotein ligand-1 (PSGL-1) is a major ligand for P-selectin expressed in a selectin-binding form on myeloid cells and subsets of lymphoid cells.

Matrix metalloproteinase-1 produced by human CXCL12-stimulated natural killer cells.

Natural killer (NK) cells play a key role in inflammation and tumor regression through their ability to migrate into tissues. CXCL12 is a chemokine that promotes lymphocyte invasion and migration into tissues; however, the mechanism for this process remains incompletely understood. In this study, we show that CXCL12 significantly enhanced CD16(+)CD56(+) human peripheral NK-cell invasion into type I collagen by the catalytic activity of matrix metalloproteinase-1 (MMP-1).

Effect of nonspecific binding to microsomes and metabolic elimination of buprenorphine on the inhibition of cytochrome P4502D6.

Recently, the pharmaceutical industry has employed the high-throughput method for the evaluation of cytochrome P450 (CYP) inhibition, using a combination of the heterologously expressed enzyme and a fluoregenic substrate. When buprenorphine (BN), a potent mixed agonist-antagonist analgesic, was evaluated by this method, it exhibited potent inhibition of CYP2D6 with an IC50 value of 0.25 microM in recombinant CYP2D6-expressing insect cell microsomes (rCYP2D6 microsomes).

A direct binding site for Grb2 contributes to transformation and leukemogenesis by the Tel-Abl (ETV6-Abl) tyrosine kinase.

A direct binding site for the Grb2 adapter protein is required for the induction of fatal chronic myeloid leukemia (CML)-like disease in mice by Bcr-Abl. Here, we demonstrate direct binding of Grb2 to the Tel-Abl (ETV6-Abl) fusion protein, the product of complex (9;12) chromosomal translocations in human leukemia, via tyrosine 314 encoded by TEL exon 5. A Tel-Abl point mutant (Y314F) and a splice variant without TEL exon 5 sequences (Deltae5) lacked Grb2 interaction and exhibited decreased binding and phosphorylation of the scaffolding protein Gab2 and impaired activation of phosphatidylinositol 3-kinase, Akt, and extracellular signal-regulated kinase/mitogen-activated protein kinase in hematopoietic cells.

AML1-ETO expression is directly involved in the development of acute myeloid leukemia in the presence of additional mutations.

The t(8;21) is one of the most frequent chromosomal abnormalities associated with acute myeloid leukemia (AML). The translocation, which involves the AML1 gene on chromosome 21 and the ETO gene on chromosome 8, generates an AML1-ETO fusion transcription factor. To examine the effect of the AML1-ETO fusion protein on leukemogenesis, we made transgenic mice in which expression of AML1-ETO is under the control of the human MRP8 promoter (hMRP8-AML1-ETO).

Dichotomy of AML1-ETO functions: growth arrest versus block of differentiation.

The fusion gene AML1-ETO is the product of t(8;21)(q22;q22), one of the most common chromosomal translocations associated with acute myeloid leukemia. To investigate the impact of AML1-ETO on hematopoiesis, tetracycline-inducible AML1-ETO-expressing cell lines were generated using myeloid cells. AML1-ETO is tightly and strongly induced upon tetracycline withdrawal.

Analysis of the role of AML1-ETO in leukemogenesis, using an inducible transgenic mouse model.

As reported previously, AML1-ETO knock-in mice were generated to investigate the role of AML1-ETO in leukemogenesis and to mimic the progression of t(8;21) leukemia. These knock-in mice died in midgestation because of hemorrhaging in the central nervous system and a block of definitive hematopoiesis during embryogenesis. Therefore, they are not a good model system for the development of acute myeloid leukemia.

Down-regulation of CXCR2 expression on human polymorphonuclear leukocytes by TNF-alpha.

TNF-alpha is implicated in the initiation of cytokine cascades in various inflammatory settings. To assess the interactions of multiple cytokines at the level of inflammatory effector cells, we examined the effects of TNF-alpha on the expression of two IL-8Rs (CXCR1 and CXCR2) on polymorphonuclear leukocytes (PMNs). TNF-alpha decreased the surface expression of CXCR2 in a dose- and time-dependent manner.

Leukotriene B4-activated human endothelial cells promote transendothelial neutrophil migration.

We explored the effect of leukotriene B4 (LTB4) on endothelial cells in LTB4-induced transendothelial migration (TEM) of neutrophils as an in vitro model of neutrophil extravasation. Chemotactic response of human neutrophils to LTB4 was significantly lower than that in response to N-formyl-methionyl-leucyl-phenylalanine (fMLP), whereas the extent of TEM in response to LTB4 was significantly higher than that to fMLP. The study on random migration induced by LTB4 and fMLP also showed similar results, which indicated that LTB4 might affect the human umbilical cord vein endothelial cell (HUVEC) barrier.

Demonstration of functionally distinct human polymorphonuclear leukocyte fractions by simultaneous measurement of phagocytosis and oxygen radical generation.

Phagocytosis and oxygen radical generation by human polymorphonuclear leukocytes (PMNLs) were studied by a two-color flow cytometric analysis, where the red fluorescent product(s) of hydroethidine was used as an indicator of intracellular generation of oxygen radicals and opsonized zymosan (OZ) as an indicator of phagocytosis. Unstimulated cells formed a single population of cells without any significant fluorescence. PMNLs stimulated by OZ exhibited a high red fluorescence.

Random migration of polymorphonuclear leukocytes induced by GM-CSF involving a signal transduction pathway different from that of fMLP.

Granulocyte-macrophage colony-stimulating factor (GM-CSF) induced random migration of human polymorphonuclear leukocytes (PMNs) but not chemotaxis. Chemoattractants such as N-formyl-methionyl-leucyl-phenylalanine (fMLP), leukotriene B4 (LTB4), and interleukin-8 (IL-8) induced both random migration and chemotaxis. Other inflammatory cytokines, including granulocyte colony-stimulating factor (G-CSF), interleukin 1alpha (IL-1alpha), and tumor necrosis factor alpha (TNF-alpha), did not induce either movement.

Pharmacokinetics of human activated protein C. 1st communication: plasma concentration and excretion of a lyophilized purified human activated protein C after intravenous administration in the mouse and the rabbit.

Pharmacokinetic studies of human activated protein C (CAS 42617-41-4, APC) were investigated in mice and rabbits with 125I-labeled compound. Plasma levels of APC were determined by three different assays: total radioactivity, APC antigenicity determined by sandwich enzyme-linked immunosorbent assay (ELISA), and the amidolytic activity which was performed by immunologically captured APC. APC concentration obtained from these assays were shown to be correlated well at early times post-dose.

[Complete remission in acute myeloblastic leukemia (M0) after treatment with rhG-CSF].

A 57-year-old man was admitted because of fever and night sweat. The bone marrow was hypercellular with 86.4% blast cells.

Mechanism of leukemic cell lysis by activated human macrophages: leukemic cells can be lysed without direct contact.

We recently reported that human macrophages effectively destroyed leukemic cells. In this study, we investigated the mechanism of leukemic cell lysis by human macrophages. Human peripheral blood monocyte-derived macrophages were activated with interferon-gamma and lipopolysaccharide.

Leukemic cell lysis by activated human macrophages: significance of membrane-associated tumor necrosis factor.

In this study, we analyzed the mechanism(s) of leukemic cell lysis by human macrophages. Peripheral blood monocyte-derived macrophages were activated with recombinant interferon-gamma and lipopolysaccharide and their lytic activity against two leukemic cell lines (K562 and HL-60 cells) was assessed by an 111In releasing assay. Activated macrophages lysed these leukemic cells, and the lytic activity against leukemic cells was almost completely inhibited by anti-tumor necrosis factor (TNF) antibody.