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Biomedical subjects

A Abe

Publications and source records attributed to A Abe.

At least 163 records · Page 9Linked to original sources
PubMed1995

Degradation of polyaromatic hydrocarbons by organic solvent-tolerant bacteria from deep sea.

We isolated three organic solvent (OS)-tolerant bacterial strains DS-1051, DS-1902, and DS-313 from a depth of 1,168 m in Sagami Bay, Japan. These isolates were tolerant to various kinds of toxic OSs such as benzene, toluene, and p-xylene. They also could degrade polyaromatic hydrocarbons, naphthalene or biphenyl, in a medium-OS (9:1) two-liquid-phase system. Percentage degradation of polyaromatic hydrocarbons in OS by these strains were higher than those obtained from cultures in which substrates were in the medium without OS.

Bacteria↗
PubMed1995

Primary hyperparathyroidism associated with multiple myeloma.

A 73-year-old woman was diagnosed as primary hyperparathyroidism. Hypercalcemia recurred after parathyroidectomy, though serum calcium concentration temporarily resumed to normal. Hypercalcemia was eventually shown to be due to multiple myeloma. In spite of the frequent association of hypercalcemia with malignant disease and the relative frequency of primary hyperparathyroidism as a cause of hypercalcemia, primary hyperparathyroidism accompanied by multiple myeloma has been considered in only a limited number of reports. Here, the cases in the literature are reviewed and discussed.

Adenoma↗
PubMed1995

Polymorphism and Distribution of Apo(a).

Several apo(a) isoforms, controlled by a series of alleles Lp(a)F, Lp(a)B, Lp(a)S1, Lp(a)S2, Lp(a)S3, Lp(a)S4 and null, were found in 470 healthy Japanese by 4% SDS-PAGE and immunoblotting techniques. There was a strong inverse relationship between the apparent molecular weight of apo(a) isoforms and plasma concentrations of Lp(a). Lp(a) in d < 1.006 fraction increased 2-4h after oral fat load. Lp(a) exhibited a marked avidity for triglyceride-rich lipoprotein (TRL), and we suggest that the TRL-bound Lp(a) is the intact Lp(a) derived from serum. We demonstrated that the lipid-free apo(a) does not contain apo B-100 in serum, and has a molecular mass of ca 200 kDa. The free apo(a) level in normal subjects was 1.75 mg/dl (as Lp(a)) and was no different from the level in CAD patients.

Coronary Disease↗
PubMed1995

Structural and stereochemical studies of potent inhibitors of glucosylceramide synthase and tumor cell growth.

Analogs and homologs of PDMP were synthesized, based on its structure (D-threo-1-phenyl-2-decanoylamino-3-morpholino-1-propanol). This compound had previously been found to block the synthesis of GlcCer (glucosylceramide). Increasing the acyl chain length from 10 to 16 carbon atoms greatly enhanced the efficacy of the enzyme inhibitor, as did the use of a less polar cyclic amine, especially a pyrrolidine instead of a morpholine ring. Replacement of the phenyl ring by a chain corresponding to sphingosine also yielded a strongly inhibitory material. By using a chiral synthetic route, we showed that the isomers active against GlcCer synthase had the R,R-(D-threo)-configuration. However, strong inhibition of the growth of human cancer cells in plastico was produced by both the threo and erythro racemic compounds, showing involvement of an additional factor (beyond simple depletion of cell glycosphingolipids by blockage of GlcCer synthesis). The growth arresting effects could be correlated with increases in cellular ceramide and diglyceride levels. The aliphatic pyrrolidino compound was strongly inhibitory toward the glucosyltransferase and produced almost complete depletion of glycolipids, but did not inhibit growth or cause an accumulation of ceramide. Attempts were made to see whether the differences in growth effects could be attributed to the influence of the inhibitors on related enzymes (ceramide and sphingomyelin synthase and ceramidase and sphingomyelinase). While some stimulation of enzyme activity was noted, particularly at high inhibitor concentrations (50 microM), these findings did not explain the differing effects of the different inhibitors. The best inhibitors of GlcCer synthase compared favorably in efficacy with some cancer chemotherapeutic drugs in current use when tested with a battery of human cancer cells.

Animals↗
PubMed1995

Establishment and characterization of an immature human megakaryoblastic cell line, MEG-A2.

We have established a novel human megakaryoblastic cell line, designated as MEG-A2, from a patient with megakaryoblastic crisis of Philadelphia (Ph) chromosome positive chronic myelogenous leukemia. MEG-A2 cells showed positive phenotypes for periodic acid Schiff and alpha-naphthylbutyrate esterase reactions, but were negative for myeloperoxidase and naphthol ASD chloroacetate esterase reactions. Flow cytometric analyses of cell surface markers revealed that MEG-A2 cells had a low level of GP IIb/IIIa expression as well as apparent expressions of CD4, CD7, CD13, CD33 and CD34 antigens, but no expression of GP Ib nor glycophorin A. Stimulation with phorbol 12-myristate 13-acetate (PMA) dramatically increased the expression of megakaryocyte-related markers such as HPL-3, J15, Pit-1, Y2/51 and AN51 in MEG-A2 cells. The PMA-stimulation also induced expression of platelet peroxidase (PPO) in MEG-A2 cells on electromicroscopic observation. Proliferative responses to granulocyte-macrophage colony-stimulating factor (GM-CSF), interleukin-3 (IL-3) or erythropoietin were observed, and the expression of GP IIb/IIIa was increased by stimulation with GM-CSF, IL-3, erythropoietin and interleukin-6 (IL-6). Protein S mRNA expression was seen in cultured cells on Northern blot analysis. Expression of platelet factor 4 mRNA was induced in PMA-stimulated cells, and a marked accumulation of protein was observed in the culture medium. In conclusion, a new cell line, MEG-A2, belongs to the relatively immature megakaryocytic lineage and has markedly increased megakaryocytic characteristics with PMA stimulation.

Adult↗
PubMed1994

High-performance liquid chromatograpy-thermospray mass spectrometry of omega-hydroxy polyunsaturated fatty acids from rat brain homogenate.

A method for the analysis of omega-hydroxy polyunsaturated fatty acids (omega-HPUFAs) in rat tissue homogenate, supplemented with NADPH and homo-gamma-linolenic acid [20:3(n-6)], arachidonic acid [20:4(n-6)], eicosapentaenoic acid [20:5(n-3)] or docosahexaenoic acid [22:6(n-3)] as a substrate was developed. By ion analysis of chromatograms obtained with reversed-phase HPLC-thermospray MS, many omega-HPUFAs corresponding to each precursor fatty acid could be characterized by the high intensity of the molecular ion (MH+) and quasimolecular ion (MNH4+, MNa+), while other common HPUFAs were characterized by the high intensity of the base ion of MH+--H2O. On a selected-ion monitoring chromatogram of rat brain homogenate, significant amounts of omega-HPUFA from each precursor fatty acid, especially from 22:6(n-3), were detected compared with the amounts found in rat large intestine homogenate. Based on these results, a highly active NADPH-dependent omega-oxidation system is suggested for rat brain homogenate resulting in extensive oxidation of 22:6(n-3).

Animals↗
PubMed1994

Influence of chemicals commonly found in a water environment on the Salmonella mutagenicity test.

The influence of 16 organic chemicals commonly found in a water environment--such as phenols, phthalic esters and phosphoric esters--on the Salmonella mutagenicity test was investigated. The test chemicals were subjected to the mutagenicity test using a fixed dose of various positive standard mutagens such as 2-nitrofluorene, Trp-P-1, Trp-P-2, 2-aminofluorene and benzo[a]pyrene, thus testing them for their influence on the mutagenic activities. The influence of each chemical was classified into one of five groups as follows: (1) toxic and inhibitory to mutagenicity; (2) toxic and promotive to mutagenicity; (3) non-toxic and inhibitory to mutagenicity; (4) non-toxic and promotive to mutagenicity; and (5) non-toxic and having no effect on mutagenicity. It is concluded that chemicals in the water environment may influence the results of a mutagenicity test on environmental samples. In particular, an effect may be noted with regard to wastewater and sediments which contain these chemicals in higher concentrations eventhough they themselves are not mutagenic.

Hydrocarbons↗
PubMed1994

Ceramide regulates oxidant release in adherent human neutrophils.

We investigated the role of sphingolipids in regulating oxidant release in adherent human neutrophils. Stimulation of adherent neutrophils with formyl-Met-Leu-Phe (fMLP) resulted in the accumulation of ceramide at a time when H2O2 release is terminated. H2O2 release in fMLP-stimulated neutrophils was suppressed in a concentration-dependent manner by the exogenous addition of several free sphingoid amines and short chain ceramides. Sphingosine, dihydrosphingosine, phytosphingosine, N-acetylsphingosine, and N-acetylphytosphingosine, but not N-acetyldihydrosphingosine, inhibited formyl peptide-stimulated oxidant release. The half-maximal inhibitory concentrations of N-acetylsphingosine and N-acetylphytosphingosine were 0.51 and 0.38 microM, respectively. Sphingosine, dihydrosphingosine, and phytosphingosine were less potent inhibitors with half-maximal inhibitory concentrations of 1.78, 15.4, and 1.48 microM, respectively. The 4 beta-phorbol 12 beta-myristate 13 alpha-acetate-induced respiratory burst was inhibited by 5 microM of sphingosine but not by 5 microM of N-acetylsphingosine. The effects of N-acetyl-conjugated sphingols (C2 ceramides) on phosphatidylcholine-specific phospholipase D and phosphatidic acid phosphohydrolase were markedly different from the effects of the related sphingoid bases. Both C2 ceramides and sphingoid bases partially inhibited the diradylglycerol formation by the phosphatidylcholine-specific phospholipase D pathway. Under the same conditions, however, N-acetyldihydrosphingosine and dihydrosphingosine failed to suppress H2O2 release in fMLP-stimulated neutrophils. These findings demonstrate that C2 ceramides inhibit H2O2 generation in fMLP-stimulated neutrophils via protein kinase C- or sphingoid base-independent mechanisms. The effect of ceramide in inhibiting the respiratory burst is structurally specific, because either a 4,5-trans double bond or 4-hydroxyl group is required for the inhibition. Therefore, ceramides may regulate oxidant release in adherent neutrophils.

Cell Adhesion↗
PubMed1994

Phospholipase D-mediated diradylglycerol formation coincides with H2O2 and lactoferrin release in adherent human neutrophils.

Polymorphonuclear leukocytes (PMNs) adherent to fibrinogen exhibit a delay in the onset of the respiratory burst in response to N-formyl-methionyl-leucyl-phenylalanine (fMLP). Previously, we demonstrated that H2O2 release in adherent PMNs coincides with the exocytosis of lactoferrin-containing specific granules. Since diradylglycerol (DRG) has been implicated in PMN secretion and oxidant release, we measured DRG formation during PMN adhesion to fibrinogen. PMNs were added to fibrinogen-coated plastic in the presence of fMLP, and H2O2 release, lactoferrin release, and DRG formation measured over a time course of 120 min. H2O2 and lactoferrin release were not apparent until 45-60 min, reaching maximal levels by 120 min. In contrast, DRG concentration increased by 15-30 min, from 275 +/- 27 pmol/mg of protein in resting cells to 600 +/- 173 pmol/mg protein in cells exposed to fMLP. DRG levels returned to base line by 30-45 min (383 +/- 32 pmol/mg of protein) before increasing again between 60 and 120 min (944 +/- 230 pmol/mg of protein and 1632 +/- 351 pmol/mg of protein, respectively). Propranolol, an inhibitor of phosphatidate phosphohydrolase, caused a dose-dependent inhibition of both H2O2 and lactoferrin release, with maximal inhibition at 50-100 microM. Propranolol also inhibited the second, but not the first phase of DRG formation. Similarly, ethanol treatment completely blocked H2O2 and lactoferrin release, and the second phase of DRG formation. In the presence of ethanol, phospholipase D (PLD)-mediated formation of [3H]phosphatidylethanol from 3H-O-alkyl-phosphatidylcholine corresponded to the second, but not the first, phase of DRG formation (23,169 +/- 2,017 cpm/mg protein, ethanol versus 2,696 +/- 261 cpm/mg protein, control). These data indicate that DRG, generated through the activation of PLD, plays an important role in degranulation and oxidant release in adherent PMNs.

Cell Adhesion↗
PubMed1994

High-performance liquid chromatography-thermospray mass spectrometry of epoxy polyunsaturated fatty acids and epoxyhydroxy polyunsaturated fatty acids from an incubation mixture of rat tissue homogenate.

A method for the analysis of epoxy polyunsaturated fatty acids (EpPUFAs) and epoxyhydroxy polyunsaturated fatty acids (EpHPUFAs) in rat tissue homogenate, with homo-gamma-linolenic acid (20:3, n - 6), arachidonic acid (20:4, n - 6), eicosapentaenoic acid (20:5, n - 3) or docosahexaenoic acid (22:6, n - 3) as a substrate, has been developed. Extraction with dichloromethane at pH 4-5 and concentration in the presence of pyridine were performed. Spectral analysis of chromatograms obtained with high-performance liquid chromatography-thermospray mass spectrometry showed the presence of EpPUFAs, EpHPUFAs and dihydroxy metabolites (DiHPUFAs) of EpPUFAs corresponding to each precursor fatty acid. On a selected-ion monitoring chromatogram, many EpPUFAs, EpHPUFAs and DiHPUFAs in an extract from an incubation mixture of each precursor fatty acid in aged rat tissue homogenate were detected simultaneously within 70 min. EpPUFAs and DiHPUFAs derived from 20:3 (n - 6) or 20:5 (n - 3) were detected in significant amounts. From these results, a highly active cytochrome P450 system or non-enzymic oxidative reactions in aged rat tissue homogenate were suggested.

Animals↗
PubMed1994

Role of diradylglycerol formation in H2O2 and lactoferrin release in adherent human polymorphonuclear leukocytes.

Polymorphonuclear leukocytes (PMNs) adherent to fibrinogen exhibit a delay in the release of H2O2 in response to fMLP. Previously, we demonstrated that H2O2 release in adherent PMNs coincides with the exocytosis of lactoferrin-containing specific granules and activation of phospholipase D (PLD). We also found that chelation of intracellular calcium blocked both lactoferrin and H2O2 release in stimulated PMNs in spite of the fact that adhesion and spreading remained normal. Since diradylglycerol (DRG) formation has been implicated in PMN secretion and oxidant release, we determined the effect of intracellular calcium chelation on PLD activation and DRG formation to ascertain whether DRG formation was coupled to lactoferrin and H2O2 release. We observed that chelation of intracellular calcium with bis-(O-aminophenoxy)-ethanol-N,N;N'-tetraacetic acid (BAPTA) prevented PLD activation as monitored by inhibition of phosphatidylethanol formation. Formation of DRG derived from phosphatidic acid (PA) was also inhibited in the presence of BAPTA. Following the addition of the calcium ionophore ionomycin to the BAPTA-treated PMNs, lactoferrin and H2O2 release was coincident with the onset of DRG formation. Also the addition of sn-1,2-didecanoylglycerol to the BAPTA-treated PMNs stimulated them to release H2O2. Our studies support the hypothesis that DRG derived from PLD activation is required for degranulation of specific granules and associated H2O2 release from adherent PMNs.

Amino Acid Sequence↗
PubMed1994

Lp(a): an acute-phase reactant?

The present study was designed to confirm the transient increases of plasma Lp(a) levels as an acute-phase reactant and to clarify the significance of these increases with the use of patients with acute myocardial infarction and patients subjected to surgical operations. Although interleukin 6, C-reactive protein and alpha 1 antitrypsin reached the maximal levels 1-2 days, 3 days and 4-5 days, respectively, after the episodes, the peak time of Lp(a) levels was delayed some extent in both patient groups. Studying the transient increases of Lp(a) levels as a function of apo(a) isoforms analyzed by density-gradient ultracentrifugation and SDS-PAGE, the higher-density Lp(a) particles preferentially containing high-molecular-weight apo(a) isoforms increased more than the lower-density Lp(a) particles containing low-molecular-weight apo(a) after the episodes. The immunohistochemical findings suggest that Lp(a) may play an important role as an acute-phase reactant in the repair of tissue injury, especially in the process of angiogenesis.

Acute-Phase Reaction↗
PubMed1994

Fully mechanized latex immunoassay for serum lipoprotein(a).

We have developed a fully automated system to quantify lipoprotein(a) (Lp(a)) in human serum, based on the latex-enhanced turbidimetric immunoassay by application of the Immuno Chemistry Analyzer 501X. This assay was carried out with undiluted serum and was able to detect at Lp(a) levels higher than 4.0 mg/l. When judged to be out of range of the calibration (> 600 mg/l), the sample was automatically re-tested after automatic 10-fold dilution. Within-run C.V.s ranged from 1.9 to 2.1% and between-run C.V.s from 2.7 to 3.9%. Results by the present method were in good agreement with those by the in-house ELISA (r = 0.978) and the commercial ELISA (r = 0.990). The distribution of Lp(a) levels in sera from 508 healthy donors was highly skewed; the mean and median were 158 mg/l and 105 mg/l, respectively.

Adolescent↗
PubMed1994

Humoral and cellular immunity to an encoded protein induced by direct DNA injection.

An immunization procedure with naked DNA that generates both humoral and cellular immune responses is described. A mammalian expression vector encoding human factor IX as an example of immunogen was injected into mice three times at 10-day intervals. Three of the 4 mice in which the DNA was injected intramuscularly and 5 of the 9 mice injected subcutaneously produced antibodies to human factor IX. Spleen cells from inoculated mice also showed significant cytotoxic T lymphocyte response to target cells expressing human factor IX. The titers of anti-single-stranded (ss)DNA antibodies were significantly higher in the subsets of genetically inoculated mice than in the control mice, but anti-double-stranded (ds)DNA antibodies were not detected in any serum samples. Thus, intramuscular and subcutaneous injection of plasmid DNA can induce immune responses against the encoded protein without an exposure to virus particles, and this approach may serve as the basis for immunotherapy in the treatment of cancer and infectious diseases in humans.

Animals↗
PubMed1994

Virulence region of plasmid pNL2001 of Salmonella enteritidis.

The virulence region of the Salmonella enteritidis 55 kb plasmid pNL2001 was identified by Tn1-insertion mutagenesis, DNA hybridization studies, and Western blot analysis of proteins encoded in the virulence region of the plasmid. DNA hybridization studies showed that the pNL2001 plasmid contained a 6.4 kb SalI-EcoRI fragment homologous to the 6.4 kb SalI-EcoRI Salmonella plasmid virulence (spv) region of the S. choleraesuis 50 kb plasmid (pKDSC50). One of the 247 Tn1-insertion mutants of S. enteritidis, designated strain TA19, showed a reduced mouse lethality, and the Tn1-insertion of strain TA19 was located within this homologous 6.4 kb region, suggesting that the 6.4 kb SalI-EcoRI fragment of pNL2001 contained the spv region. Two contiguous SalI-EcoRI fragment were cloned into the expression vectors. By the 6.4 kb SalI-EcoRI fragment were cloned into the expression vectors. By Western blot analysis using four Spv peptide antisera, each specific for individual proteins encoded in the spvR, spvA, spvB and spvC genes of pKDSC50, four proteins encoded in the 6.4 kb SalI-EcoRI fragment of pNL2001 were identified. Protein SpvR with an apparent molecular mass of 32 kDa was produced from the 2.3 kb SalI-EcoRI fragment, and protein SpvA, SpvB and SpvC with apparent molecular masses of 32, 70 and 29 kDa, respectively, were produced from the 4.1 kb EcoRI-EcoRI fragment. From the 4.1 kb EcoRI::Tn1 fragment of the TA19 plasmid, proteins SpvA and SpvB were expressed, but not SpvC. It was therefore suggested that the spvC gene may contribute to the expression of virulence of S. enteritidis. Furthermore, the nucleotide sequence of the 6.4 kb SalI-EcoRI fragment encoding these four proteins was determined. Four open reading frames which encoded the four proteins with deduced molecular masses of 33,906, 28,200, 65,349 and 27,646 Da were detected. Deduced amino acid sequences of each protein showed a high degree of identity to corresponding sequences in the virulence region of S. choleraesuis, S. dublin and S. typhimurium virulence plasmids. Therefore, we confirmed that the virulence plasmids of Salmonellae including S. enteritidis share the highly conserved region responsible for virulence.

Amino Acid Sequence↗
PubMed1994

Regulation of spvR gene expression of Salmonella virulence plasmid pKDSC50 in Salmonella choleraesuis serovar Choleraesuis.

The expression regulation of spvR, a regulatory gene on the virulence plasmid (pKDSC50) of Salmonella choleraesuis serovar Choleraesuis, was investigated by spvR-lacZ translational fusion. The spvR gene was found to be positively regulated by its own product, the SpvR protein, and this unusual positive autoregulation was repressed by the products of spvA and spvB, virulence-associated genes present downstream from the spvR gene. Amino acid sequence analysis revealed that the amino-terminal region of SpvB had homology with the CatM repressor protein of Acinetobacter calcoaceticus, which belongs to the MetR/LysR protein family. On the other hand, the sigma factor RpoS was required for expression of the spvR gene in the stationary phase of bacterial growth. The SpvR protein was also necessary for self-activation, suggesting that an RNA polymerase holoenzyme containing RpoS requires SpvR protein in order to recognize the spvR promoter.

Base Sequence↗
PubMed1994

[Complete remission during administration of rhG-CSF in acute myeloblastic leukemia with pneumonia].

A 54-year-old man was admitted with pneumonia and pancytopenia (WBC 400/microliters, RBC 297 x 10(4)/microliters, Hb 10.1g/dl, Plt 5.6 x 10(4)/microliter). Bone marrow aspiration revealed a proliferation of leukemic cells (61.6%) and led the diagnosis of AML (M2). Although no antileukemic agent had been administered previously, the combination therapy of antimicrobials and rhG-CSF for the infection not only improved pneumonia, but also induced a complete remission of AML. The short-term remission was followed by the first relapse of AML, in spite of the continuous administration of rhG-CSF. The abnormal karyotype (47, XY, +8) shown in the chromosomal analysis of the bone marrow cells at admission remained on the first remission. The second complete remission was induced by combination chemotherapy (BHAC-DMP), and the chromosomal analysis at this time showed a normal karyotype. These findings suggested that the first remission of AML in this case was caused mainly by the maturation induction effect of rhG-CSF on the leukemic cells, however, the possibility of the spontaneous remission in this case also remained.

Antineoplastic Combined Chemotherapy Protocols↗