PubMed Health⌕ Search

Biomedical subjects

H Wakabayashi

Publications and source records attributed to H Wakabayashi.

At least 19 recordsLinked to original sources
PubMed1995

Purification and identification of mouse lung microvessel endothelial cell-derived chemoattractant for lung-metastasizing murine RAW117 large-cell lymphoma cells: identification as mouse monocyte chemotactic protein 1.

We reported recently that medium conditioned with mouse lung microvessel endothelial cells possessed chemotactic activity for a highly lung-metastatic variant (L17) of the RAW117 murine large-cell lymphoma cell line but not for the poorly metastatic parental cells (P) or a liver-metastasizing variant (H10). The chemotactic factor was purified to homogeneity by a five-step procedure involving hydrophobic interaction, Cibacron blue F3GA affinity, metal affinity, anion exchange, and reversed phase chromatography, followed by preparative gel electrophoresis. The purified material appeared as a single broad band when analyzed by SDS-PAGE, with an average molecular weight of 26,000. The factor was cleaved by cyanogen bromide treatment, and a partial amino acid sequence of one of the cleaved polypeptides proved identical to mouse monocyte chemotactic protein 1 (mMCP-1/JE). The amino acid composition of the factor also indicated similarity to mMCP-1/JE. Separately purified mMCP-1/JE significantly stimulated the chemotactic migration of RAW117 cells (L17 >> H10, P). When recombinant human monocyte chemotactic protein 1 was compared to the purified endothelial cell chemotactic factor as a chemoattractant, similar migratory responses were observed in the RAW117 sublines. The chemotactic activity for L17 cells was significantly reduced from lung microvessel endothelial cell-conditioned medium after treatment with anti-mouse MCP-1 antibody. In contrast, the migration-stimulating activity of liver sinusoidal endothelial cell-conditioned medium to H10 cells was not affected by anti-mouse MCP-1. A major function of mMCP-1/JE is to recruit monocytes to inflammatory sites, and our results suggest that mMCP-1/JE also facilitates lymphoma lung invasion and metastasis.

Amino Acid Sequence↗
PubMed1995

Ca2+ channel blocker, diltiazem, prevents physical dependence and the enhancement of protein kinase C activity by opioid infusion in rats.

The influence of an L-type Ca2+ channel blocker, diltiazem [(2S-cis)-3-(acetyloxy)-5-[2-(dimethylamino)-ethyl]-2,3-dihydro-2- (4- methoxyphenyl)-1,5-benzothiazepin-4(5H)-one], on the behavioral signs of naloxone (opioid receptor antagonist)-precipitated withdrawal syndrome and the enhancement of protein kinase C activity in the pons/medulla regions of rats rendered dependent on morphine (mu-opioid receptor agonist) or butorphanol (mu/delta/kappa mixed opioid receptor agonist) was investigated. The expression of physical dependence produced by continuous intracerebroventricular (i.c.v.) infusion of morphine (26 nmol/microliters per h) or butorphanol (26 nmol/microliters per h) for 3 days, as evaluated by naloxone (5 mg/kg, i.p.)-precipitated withdrawal signs, was dose dependently attenuated by concomitant infusion of diltiazem (10 and 100 nmol/microliters per h). Furthermore, diltiazem (100 nmol/microliters per h) completely inhibited the enhancement of cytosolic protein kinase C activity in the pons/medulla regions in rats rendered dependent by continuous infusion with morphine or butorphanol. These results suggest that the augmentation of intracellular Ca2+ concentration mediated through L-type Ca2+ channels during continuous opioid infusion leads to the enhancement of cytosolic protein kinase C activity in the pons/medulla region which is intimately involved in the development and/or expression of physical dependence on opioids.

Animals↗
PubMed1995

Prediction of the early prognosis of the hepatectomized patient with hepatocellular carcinoma with a neural network.

The early prognosis of the hepatectomized patients with hepatocellular carcinoma was determined preoperatively with a perceptron-type neural network. The neural network was trained with the preoperative data of 54 example cases with the early prognosis, successful or died of hepatic dysfunction, as teaching signals. After learning these examples, the neural network came to give a precise prediction to the example data except for one case. With the learned neural network, the outcomes of the hepatectomy of 11 patients (10 successful; 1 died) were predicted prospectively with 100% precision. The usefulness of the neural network for the prediction was determined.

Adult↗
PubMed1994

The effect of FK506 on warm ischemia and reperfusion injury in the rat liver.

The protective effect of FK506 on hepatocytes against ischemia and reperfusion injury was examined by evaluating the following: the high energy phosphorus metabolism obtained using 31P magnetic resonance spectroscopy (31P-MRS) and the tissue blood flow of the liver in ischemia and the reperfusion process, mitochondrial glutamic oxaloacetic transaminase (m-GOT) and glutamic pyruvic transaminase (GPT), the survival rates of the animals, a histological study and immunohistological staining for intercellular adhesion molecule-1 (ICAM-1) in the liver after ischemia. The rats were treated with FK506 1 mg/kg/day i.m. for 4 days before testing. Ischemia was induced by clamping the hepatoduodenal ligament for 30 min. In 31P-MRS, the recovery of the hepatic energy status after ischemia, evaluated by beta-ATP/inorganic phosphate (Pi), was significantly better in the FK506 group. It also coincided with the recovery of tissue blood flow monitored with a laser Doppler flowmeter. In the histological examination, the congestion observed in the periportal region of the control group was mild, while there was less induction of ICAM-1 in the endothelial cells of the portal veins and hepatic veins in the FK506 group. From these findings, we concluded that FK506 had a protective effect on hepatocytes against warm ischemia and reperfusion injury, and the mechanism for this could partially be attributed to improved tissue blood flow after ischemia by the modulation of immunological events.

Alanine Transaminase↗
PubMed1992

Identification of the bactericidal domain of lactoferrin.

We report the existence of a previously unknown antimicrobial domain near the N-terminus of lactoferrin in a region distinct from its iron-binding sites. A single active peptide representing this domain was isolated following gastric pepsin cleavage of human lactoferrin, and bovine lactoferrin, and sequenced by automated Edman degradation. The antimicrobial sequence was found to consist mainly of a loop of 18 amino acid residues formed by a disulfide bond between cysteine residues 20 and 37 of human lactoferrin, or 19 and 36 of bovine lactoferrin. Synthetic analogs of this region similarly exhibited potent antibacterial properties. The active peptide of bovine lactoferrin was more potent than that of human lactoferrin having effectiveness against various Gram-negative and Gram-positive bacteria at concentrations between 0.3 microM and 3.0 microM, depending on the target strain. The effect of the isolated domain was lethal causing a rapid loss of colony-forming capability. Our studies suggest this domain is the structural region responsible for the bacterial properties of lactoferrin.

Amino Acid Sequence↗
PubMed1992

Specific detection of acetyl-coenzyme A by reversed-phase ion-pair high-performance liquid chromatography with an immobilized enzyme reactor.

A selective chromatographic detection system for the determination of acetyl-coenzyme A (CoA) is reported. The short-chain acyl-CoA thioesters were separated by reversed-phase ion-pair high-performance liquid chromatography (HPLC), and then acetyl-CoA was selectively detected on-line with an immobilized enzyme reactor (IMER) as a post-column reactor. Thio-CoA liberated enzymatically from acetyl-CoA was determined spectrophotometrically after reaction with Ellman's reagent in the reagent stream. The IMER with phosphotransacetylase had a substrate specificity sufficient to determine acetyl-CoA and was active and stable in the mobile phase containing methanol and the ion-pair reagent. The calibration graph was linear between 0.2 and 10 nmol, with a detection limit of 0.05 nmol. This HPLC system with detection by IMER allows the selective identification and determination of acetyl-CoA in a mixture of acetoacetyl-CoA and 3-hydroxy-3-methylglutaryl-CoA, which are difficult to separate with ion-pair HPLC.

Acetyl Coenzyme A↗
PubMed1992

Determination of idebenone in rat serum and brain by high-performance liquid chromatography using platinum catalyst reduction and electrochemical detection.

A high-performance liquid chromatographic determination of idebenone, a new cerebral metabolism-improving agent, in rat serum and brain has been developed. After separation of idebenone on a reversed-phase column, idebenone was reduced once in a platinum catalyst reduction column connected on-line, then monitored quantitatively by electrochemical detection. A linear relationship between the peak-height ratio of idebenone to the internal standard and idebenone concentration was observed in the range 0.015-50 ng with a detection limit of 5 pg (signal-to-noise ratio = 5). This method was satisfactorily rapid and sensitive, and was successfully applied to the determination of idebenone in rat serum and brain tissues.

Animals↗
PubMed1992

Substrate adhesiveness and experimental metastatic potential of rat ascites hepatoma AH7974-derived variant sublines.

Cells of an adherent subline (74AD, adhesion greater than 95%) and a floating subline (74FL, adhesion less than 1%) of rat ascites hepatoma AH7974 produced substrates containing fibronectin (FN), laminin (LN) and type IV collagen (CL-IV), with 74AD cells producing higher levels of each component. 74AD cells possessed high adhesion affinities to LN and CL-IV substrates. By contrast, 74FL cells hardly adhered to these purified attachment proteins. The difference in adhesion between the two lines in vitro tended to increase on incubation of the cells in medium containing fetal bovine serum. However, 74FL and 74AD cells adhered avidly to the extracellular matrix (ECM) of vascular endothelial cells. Although the cell-ECM adhesion apparently was not inhibited by pretreatment of the ECM with anti-FN, anti-LN and anti-CL-IV antibodies, the 74FL cell-ECM adhesion was inhibited considerably by pretreatment of the ECM with a mixture of these antibodies, especially with a combination of anti-FN and anti-LN antibodies. The lung-colonizing potential of 74FL cells was greater than that of 74AD cells, but the liver-colonizing potential of 74FL cells was less than that of 74AD cells. These results suggest that rat ascites hepatoma cells with extremely reduced substrate adhesiveness retain an adhesion mechanism that binds to FN and LN in the ECM of vascular endothelial cells. This mechanism may be a minimum essential unit of tumor cell-ECM adhesion in lung colonization, but the unit is insufficient for liver colonization of these cells.

Animals↗
PubMed1992

Antibacterial spectrum of lactoferricin B, a potent bactericidal peptide derived from the N-terminal region of bovine lactoferrin.

A physiologically diverse range of Gram-positive and Gram-negative bacteria was found to be susceptible to inhibition and inactivation by lactoferricin B, a peptide produced by gastric pepsin digestion of bovine lactoferrin. The list of susceptible organisms includes Escherichia coli, Salmonella enteritidis, Klebsiella pneumoniae, Proteus vulgaris, Yersinia enterocolitica, Pseudomonas aeruginosa, Campylobacter jejuni, Staphylococcus aureus, Streptococcus mutans, Corynebacterium diphtheriae, Listeria monocytogenes and Clostridium perfringens. Concentrations of lactoferricin B required to cause complete inhibition of growth varied within the range of 0.3 to 150 micrograms/ml, depending on the strain and the culture medium used. The peptide showed activity against E. coli O111 over the range of pH 5.5 to 7.5 and was most effective under slightly alkaline conditions. Its antibacterial effectiveness was reduced in the presence of Na+, K+, Mg2+ or Ca2+ ions, or in the presence of various buffer salts. Lactoferricin B was lethal, causing a rapid loss of colony-forming capability in most of the species tested. Pseudomonas fluorescens, Enterococcus faecalis and Bifidobacterium bifidum strains were highly resistant to this peptide.

Amino Acid Sequence↗
PubMed1992

Fibronectin degradation by human gastric carcinoma cell lines and its associated proteases in relation to stromal invasion in nude mice.

The invasiveness of human gastric carcinoma cell lines (MKN45 and MKN28) in the subcutaneous tissue of nude mice and the degrading capacities of extracellular matrix (ECM) were studied. MKN45 cells were more invasive than were the MKN28 cells. Immunostaining revealed dense lamellar accumulation of fibronectin (FN) around the tumors. Along the front of the invasive MKN45 growth, however, the FN fibers were discontinuous and/or had completely vanished; the MKN28 tumor showed no FN fiber disconnection. ECM components other than FN never displayed such peritumoral massive accumulation. Cocultivation of human fibroblasts with MKN45 cells, more evidently than with MKN28 cells, revealed degradation of FN produced by fibroblasts in contact with each tumor. Both cell lines produced several FN-degrading enzymes in serum-free cultures. Proteases from the MKN45 medium were more active than were those of MKN28 in urokinase-type plasminogen activator (uPA) and metal-dependent serine proteinase-like proteases of 75 and 68 kDa in molecular weight (MW). Type I collagen-degrading 48-kDa protease was also detected from MKN45 medium but not from the MKN28 medium. MKN28 cells secreted other kinds of FN-degrading enzymes, estimated at approximate MWs of 29 and 100-150 kDa. We found no distinct differences in capacity to produce ECM components or ability to adhere to purified ECM components between these two cell lines. From these results we conclude that the stromal invasion of these cells into the subcutaneous tissue of nude mice is profoundly related to their FN-degrading capability. This capability may be catalyzed by uPA and/or metal-dependent serine proteinase-like proteases of 75 and 68 kDa.

Adenocarcinoma↗
PubMed1991

Superoxide is involved in the pathogenesis of paraquat-induced injury in cultured rat liver slices.

We examined whether superoxide is a factor responsible for paraquat-induced liver injury in terms of superoxide dismutase using cultured rat liver slices exposed to various concentrations of paraquat. The degree of liver injury was assessed by measurement of percentage of lactate dehydrogenase leakage into the medium and lipid hydroperoxides in the liver slices and by direct histopathological observation. Paraquat produced concentration- and time-related liver injury in the cultured rat liver slices. Notably, after exposure to 5 mmol/L paraquat, a significant increase of the percentage of lactate dehydrogenase leakage occurred from 4 hr (p less than 0.05 vs. control group), and this gradually increased up to 8 hr (p less than 0.01 and p less than 0.001 vs. control group at 6 and 8 hr, respectively). Changes in lipid hydroperoxides in the liver slices were similar to those in percentage of lactate dehydrogenase leakage (p less than 0.05 and p less than 0.01 vs. control group at 6 and 8 hr, respectively). Liver injury was located around the central vein at 6 hr and gradually spread at 8 hr. Paraquat-induced liver injury was aggravated both biochemically and histopathologically by pretreatment with 5 mmol/L diethyldithiocarbamate, an inhibitor of copper- and zinc-containing superoxide dismutase activity (percentage of lactate dehydrogenase leakage: p less than 0.01 and p less than 0.001 vs. paraquat group at 6 and 8 hr, respectively; lipid hydroperoxides: p less than 0.01 vs. paraquat group at 8 hr). Incubation of liver slices with liposome-encapsulated superoxide dismutase increased the augmentation of superoxide dismutase in the liver slices.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1991

Two autopsy cases of primary leiomyosarcoma of the liver. Superiority of muscle-specific actin immunoreactivity in diagnosis.

Two autopsy cases of leiomyosarcoma of the liver in a 49-year-old female and 63-year-old male are reported. Both of the liver tumors showed electron microscopically dense patches in the cytoplasm and intermediate junctions between the tumor cells, suggesting a smooth muscle cell origin, irrespective of their different histological features. The nature of both tumors was confirmed by positive immunoreactivity for muscle-specific actin in the tumor cells, whereas desmin immunoreactivity was labile in both cases, showing a higher diagnostic value of the former compared with the latter in these leiomyosarcomas. Both cases, showed extensive distant metastases in spite of an evident difference in their mitotic indices, indicating that this index is not reliable for judging the metastatic potential of these tumors.

Actins↗
PubMed1991

Changes in alpha 1- and beta 1-adrenergic receptors and calcium ion binding sites in the fetal myocardium of spontaneously hypertensive rats (SHR).

The present study examined changes in [3H]prazosin, [125I]iodocyanopindolol and [3H]nitrendipine binding to alpha 1- and beta 1-adrenergic receptors and Ca2+ binding sites of cardiac muscle isolated from fetal Wistar Kyoto rats (WKY) and spontaneously hypertensive rats (SHR), using the radioligand binding assay method. The catecholamine concentration in the cardiac muscle of both groups was also determined. The Bmax values in beta 1-adrenoceptors and Ca2+ binding sites in SHR cardiac muscle were lower than those of WKY, but values for SHR alpha 1-adrenoceptors were higher than those of WKY. The Kd values of beta 1-adrenoceptors in cardiac muscles of SHRs were also lower than those of WKY. On the other hand, there were no differences between the catecholamine concentrations in fetal SHR and WKY cardiac muscles. Thus, significant differences in both alpha 1- and beta 1-adrenoceptors and Ca2+ binding sites were already present in fetal SHR hearts, thus suggesting that the changes in fetal hearts of SHRs may be caused by genetic defects in the mother rats at early age.

Animals↗
PubMed1991

Effects of diazepam administration on melatonin synthesis in the rat pineal gland in vivo.

The effect of diazepam (DZP) on melatonin synthesis in rat pineal gland was investigated in vivo. Subcutaneous injection of DZP (3 mg/kg) 1 h before the start of darkness significantly suppressed nocturnal elevations of pineal N-acetylserotonin (NAS) and melatonin contents in rats, and caused a 2-h delay in reaching the maximum melatonin level in the dark phase. DZP treatment also markedly suppressed the dark-induced increase of pineal N-acetyltransferase activity, which catalyzes the rate-limiting step in melatonin synthesis, but had no effect on hydroxyindole-O-methyltransferase activity, which catalyzes the final step of melatonin formation. Pineal norepinephrine and dopamine contents, in contrast, were not altered by DZP injection. The distribution rate of DZP to the brain reached the highest level 30 min after a single injection, while that to the pineal gland was observed 5 h later (i.e., 4 h after the start of darkness). It is clear that the inhibitory effect of DZP on melatonin synthesis in rat pineal gland appears concomitantly with the increase in the distribution volume of DZP into this gland. These results suggest that the inhibitory effect of DZP on melatonin synthesis results from the drug's direct action on the rat pineal gland.

Acetylserotonin O-Methyltransferase↗
PubMed1991

Effects of adrenergic blockers or bicuculline on diazepam induced changes in rat pineal melatonin synthesis in vivo and in vitro.

The effect of propranolol (PPL), phenoxybenzamine (PBZ) or bicuculline (BCL) on the diazepam (DZP)-induced changes of pineal melatonin synthesis in male rats was examined in vivo and in vitro. Administration of PBZ did not affect the inhibitory action of DZP on pineal melatonin synthesis in vivo. A single injection of PPL inhibited the pineal melatonin synthesis similarly to the administration of DZP alone, but the two drugs together did not exhibit additive or synergistic effects on the melatonin synthesis. Significant decreases in the N-acetyltransferase (NAT) activity and the N-acetylserotonin (NAS) and melatonin contents were observed in the BCL-injected group, being greater than those in the DZP-treated group. Unexpectedly, however, the combination treatment of DZP and BCL causes an increase in the NAT activity and melatonin content compared with the BCL-alone group. Incubation with DZP at higher concentrations resulted in an increase of pineal NAT activity in vitro, but this increase was inhibited by preincubation with PPL, PBZ or BCL. DZP treatment thus appeared to have different effects on pineal NAT activity in vivo and in vitro. These results suggest that both a GABAergic mechanism and peripheral benzodiazepine (BZP) receptors in rat pineal gland may be involved in the modulation of melatonin synthesis by DZP.

Acetylserotonin O-Methyltransferase↗
PubMed1991

Potent antibacterial peptides generated by pepsin digestion of bovine lactoferrin.

The antibacterial properties of enzymatic hydrolysates of bovine lactoferrin were examined to determine whether active peptides are produced from this protein. Hydrolysates prepared by cleavage of lactoferrin with porcine pepsin, cod pepsin, or acid protease from Penicillium duponti showed strong activity against Escherichia coli O111, whereas hydrolysates produced by trypsin, papain, or other neutral proteases were much less active. Low molecular weight peptides generated by porcine pepsin cleavage of lactoferrin showed broad-spectrum antibacterial activity, inhibiting the growth of a number of Gram-negative and Gram-positive species, including strains that were resistant to native lactoferrin. The antibacterial potency of the hydrolysate was at least eightfold greater than that of undigested lactoferrin with all strains tested. The active peptides retained their activity in the presence of added iron, unlike native lactoferrin. The effect of the hydrolysate was bactericidal as indicated by a rapid loss of viability of E. coli O111. The lactoferrin hydrolysate described in the present study has commercial value as a natural preservative agent for use in foods and cosmetics, and as a functional component of new clinical foods for prevention or treatment of gastrointestinal disease.

Animals↗