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K Osada

Publications and source records attributed to K Osada.

At least 19 recordsLinked to original sources
PubMed2001

Tumor cell growth inhibition and extracellular signal-regulated kinase (ERK) phosphorylation by novel K vitamins.

2-(2-hydroxy-ethylsulfanyl)-3-methyl-1,4-naphthoquinone or CPD-5, a K vitamin analog, was previously indicated to be a potent growth inhibitor for Hep 3B hepatoma cells in vitro. Here, we show that CPD-5 and two newly synthesized analogs, 2-(2-hydroxy-ethylsulfanyl)-3-methyl-5- nitro-1,4-naphthoquinone (PD-37) and 2-(2-hydroxy-ethylsulfanyl)-3- methyl-5-acetylamino-1,4-naphthoquinone (PD-42), are potent growth inhibitors of 13 different human cancer cell lines, with IC50 values in the range of 3-54 microM. Phospho-ERK was induced by each of three K vitamin analogs in every cell line in a dose-dependent manner, at growth inhibitory doses. ERK phosphorylation and growth inhibitory effects were strongly correlated, with p=0.0080 for CPD-5, p=0.0076 for PD-37 and p=0.0251 for PD-42. The induction of phospho-ERK and growth inhibition were antagonized by thiol-containing anti-oxidants, but not by catalase, consistent with a possible arylating mechanism. The data show a novel class of growth inhibitors with a wide spectrum of action that induces ERK hyper-phosphorylation, as a possible new growth inhibitory feature.

Antioxidants↗
PubMed2001

Critical role of extracellular signal-regulated kinase phosphorylation on menadione (vitamin K3) induced growth inhibition.

BACKGROUND: Although it is widely known that the extracellular signal-regulated kinase (ERK) pathway stimulates cell growth and protects cells from death, recent findings have proposed a proapoptotic action of ERK phosphorylation. Because the authors found that vitamin K3 (VK3) was a potent growth inhibitor and an inducer for ERK phosphorylation through a specific pathway in the stomach cancer cell line, the critical role of ERK phosphorylation in VK(3)-mediated growth inhibitory effect was examined. METHODS: The fluorochrome Hoechst 33258 assay (Hoechst AG [now Aventis] Frankfort, Germany) was used for counting cells (excitation at 360 nm; emission at 460 nm). For two-dimensional electrophoresis, cells were dissolved in urea standard buffer and applied first to isoelectronic focusing gels. Cell lysates were subjected to sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) using 10% polyacrylamide gels. To examine the phosphorylation of receptors, cell lysates were immunoprecipitated with receptor antibody. RESULTS: VK3 induced phosphorylation of hepatocyte growth factor receptor (c-met), epidermal growth factor receptor (EGFR), or external signal-regulated kinase (ERK), which increased progressively to a maximum level at 30 minutes, in a dose-dependent manner and occurred at growth inhibitory concentrations. VK(3)-mediated growth inhibition and protein tyrosine phosphorylation were nullified completely by glutathione or L-cysteine but not by nonthiol antioxidants, thus suggesting that sulfhydryl arylation might have been involved in VK(3)-mediated action. The phosphorylation of EGFR and c-met by VK(3) appeared to be functional, because these were coimmunoprecipitated with growth factor receptor-bound protein 2 (Grb2) and SOS1 antibody. Epidermal growth factor (EGF) or hepatocyte growth factor (HGF) stimulated increase of cyclin D1 protein after 12 hours and increased DNA content after 3 days in culture. In addition, U0126, which is a potent inhibitor for ERK phosphorylation, antagonized increase of cyclin D1, thus suggesting that EGF- or HGF-mediated ERK phosphorylation might have played an essential role for cell growth. By contrast, ERK phosphorylation by VK3 was more prolonged and intense than the signal induced by the growth factors. U0126 reduced ERK phosphorylation and prevented growth inhibition by VK3. Two-dimensional gels showed VK(3)-induced additional phospho-ERK spots, compared with those obtained from growth factors. This extra spot was completely antagonized by U0126. CONCLUSIONS: VK(3)-induced growth inhibition and protein tyrosine phosphorylation were mediated by the sulfhydryl arylation system. The tyrosine phosphorylation of EGFR or c-met by VK3 activated the Ras signaling pathway. The overexpressed ERK phosphorylation by VK3 seemed to originate from additional spots on two-dimensional gels, which played a critical role in VK(3)-induced growth inhibitory action despite the fact that ERK phosphorylation by growth factors had had an essential association with cell growth.

Apoptosis↗
PubMed2001

Tea catechins inhibit cholesterol oxidation accompanying oxidation of low density lipoprotein in vitro.

Endogenous oxidized cholesterols are potent atherogenic agents. Therefore, the antioxidative effects of green tea catechins (GTC) against cholesterol oxidation were examined in an in vitro lipoprotein oxidation system. The antioxidative potency of GTC against copper catalyzed LDL oxidation was in the decreasing order (-)-epigalocatechin gallate (EGCG)=(-)-epicatechin gallate (ECG)>(-)-epicatechin (EC)=(+)-catechin (C)>(-)-epigallocatechin (EGC). Reflecting these activities, both EGCG (74%) and ECG (70%) inhibited the formation of oxidized cholesterol, as well as the decrease of linoleic and arachidonic acids, in copper catalyzed LDL oxidation. The formation of oxidized cholesterol in 2,2'-azobis(2-amidinopropane) hydrochloride (AAPH)-mediated oxidation of rat plasma was also inhibited when the rats were given diets containing 0.5% ECG or EGCG. In addition, EGCG and ECG highly inhibited oxygen consumption and formation of conjugated dienes in AAPH-mediated linoleic acid peroxidative reaction. These two species of catechin also markedly lowered the generation of hydroxyl radical and superoxide anion. Thus, GTC, especially ECG and EGCG, seem to inhibit cholesterol oxidation in LDL by combination of interference with PUFA oxidation, the reduction and scavenging of copper ion, hydroxyl radical generated from peroxidation of PUFA and superoxide anion.

Animals↗
PubMed2000

Effects of dietary protein type on oxidized cholesterol-induced alteration in age-related modulation of lipid metabolism and indices of immune function in rats.

Exogenous oxidized cholesterol disturbs both lipid metabolism and immune functions. Therefore, it may perturb these modulations with ageing. Effects of the dietary protein type on oxidized cholesterol-induced modulations of age-related changes in lipid metabolism and immune function was examined using differently aged (4 weeks versus 8 months) male Sprague-Dawley rats when casein, soybean protein or milk whey protein isolate (WPI) was the dietary protein source, respectively. The rats were given one of the three proteins in diet containing 0.2% oxidized cholesterols mixture. Soybean protein, as compared with the other two proteins, significantly lowered both the serum thiobarbituric acid reactive substances value and cholesterol, whereas it elevated the ratio of high density lipoprotein-cholesterol/cholesterol in young rats, but not in adult. Moreover, soybean protein, but not casein and WPI, suppressed the elevation of Delta6 desaturation indices of phospholipids in both liver and spleen, particularly in young. On the other hand, WPI, compared to the other two proteins, inhibited the leukotriene B4 production of spleen, irrespective of age. Soybean protein reduced the ratio of CD4(+)/CD8(+) T-cells in splenic lymphocytes. Therefore, the levels of immunoglobulin (Ig)A, IgE and IgG in serum were lowered in rats given soybean protein in both age groups except for IgA in adult, although these observations were not shown in rats given other proteins. Thus, various perturbations of lipid metabolism and immune function caused by oxidized cholesterol were modified depending on the type of dietary protein. The moderation by soybean protein on the change of lipid metabolism seems to be susceptible in young rats whose homeostatic ability is immature. These observations may be exerted through both the promotion of oxidized cholesterol excretion to feces and the change of hormonal release, while WPI may suppress the disturbance of immune function by oxidized cholesterol in both ages. This alleviation may be associated with a large amount of lactoglobulin in WPI. These results thus showed a possibility that oxidized cholesterol-induced perturbations of age-related changes of lipid metabolism and immune function can be moderated by both the selection and combination of dietary protein.

Aging↗
PubMed2000

Cholesterol oxidation in meat products and its regulation by supplementation of sodium nitrite and apple polyphenol before processing.

The levels of cholesterol oxidation derivatives (OxChol) in eight commercial species of meat products were examined. These products contained more than 1 mg/100 g of OxChol, and 7beta-hydroxycholesterol + 5beta-epoxycholesterol (111-1092 microg/100 g), 5alpha-epoxycholesterol (80-712 microg/100 g), cholestanetriol (0-368 microg/100 g), and 7-ketocholesterol (708-1204 microg/100 g) were detected. To know the interaction of sodium nitrite supplementation against cholesterol oxidation in meat products, sausage was produced with or without varying levels of sodium nitrite and stored in the refrigerator for 15 days. As a result, cholesterol oxidation in sausage was inhibited by addition of sodium nitrite in a dose-dependent manner. This observation may be associated with inactivation of O(2)(-) radical and stabilization of polyunsaturated fatty acids (PUFAs). In fact, the levels of OxChol in sausage increased, accompanying the decrease of coexisting linoleic acid when sodium nitrite was not added to sausage meat. Thus, cholesterol oxidation in meat products seems to be considarably promoted by the oxidation of coexisting PUFAs. On the other hand, additive apple polyphenol also inhibited linoleic acid oxidation in sausage and then suppressed cholesterol oxidation through its radical scavenging effects. Therefore, apple polyphenol, having a large amount of an oligomer of catechin, may interfere with cholesterol oxidation in meat processing or storage of meat products through its antioxidative action and be useful as a new antioxitant for meat products when it is added to the original meat before processing.

Cholesterol↗
PubMed2000

Guidelines for irradiation of blood and blood components to prevent post-transfusion graft-vs.-host disease in Japan.

The Japanese Red Cross analysed the results of questionnaires sent in 1993 regarding post-transfusion graft-vs.-host disease (PT-GVHD) from hospitals; the majority of patients with PT-GVHD in 1993 were transfused for cardiovascular or cancer surgery, and about 10 patients had died yearly from PT-GVHD in the following few years. The Japan Society of Blood Transfusion (JSBT) organized a subcommittee for the prevention of PT-GVHD, and issued a fourth version of guidelines for the irradiation of blood to prevent PT-GVHD. These guidelines recommended transfusion of irradiated blood for cardiosurgery, cancer surgery, elderly recipients and severe trauma, as well as congenital immunodeficient recipients, newborn infants and other immunocompromised patients. Also recommended was irradiation not only of blood within 72 h after collection but also of blood stored for 14 days. Reported PT-GVHD has diminished to a few cases in recent years.

Blood↗
PubMed2000

Effect of oxidized cholesterol on age-associated changes to immune parameters in spleen lymphocytes and peritoneal exudate cells derived from rats.

The effects of oxidized cholesterol on immune parameters were examined by using spleen lymphocytes and peritoneal exudate cells (PEC) derived from 5-week- (Young) and 9-month-old (Adult) rats. The immunoglobulin (Ig) G and IgM production was inhibited by oxidized cholesterol in the rats of both ages when lymphocytes were exposed to 30 micrograms/ml of oxidized cholesterol for 24 hr. The intracellular IgA level was also lowered by 30 micrograms/ml of oxidized cholesterol, irrespective of age. In contrast, IgE production was significantly increased by the addition of 30 micrograms/ml of oxidized cholesterol in only young lymphocytes. Moreover, oxidized cholesterol enhanced the intracellular histamine accumulation in only adult PEC, although the total histamine level produced by PEC was similar in the rats of both ages. These results thus suggest the possibility that oxidized cholesterol can have different effects on the age-related modulation of immune functions such as Igs production and histamine release.

Aging↗
PubMed2000

Lower plasma triglyceride level in Syrian hamsters fed on skim milk fermented with Lactobacillus casei strain Shirota.

The effect of fermented skim milk (FSM) by Lactobacillus casei strain Shirota on plasma lipids in hamsters was examined. Hamsters fed on cholesterol-free and -enriched diets containing 30% FSM had lower levels of plasma triglyceride than those fed on the control diet. In the experiment with the cholesterol-enriched diet-fed hamsters, the plasma triglyceride level was suppressed by FSM at concentrations of 10% to 30%. Unfermented milk tended to lower the level of triglyceride, but not significantly. The plasma cholesterol concentration was not affected by an FSM and unfermented skim milk supplement to the diet. L. casei strain Shirota grew well in the presence of mixed lipid micelles containing bile acid, but did not have the ability to remove cholesterol from the culture broth. These results indicate that FSM lowered the plasma triglyceride level in hamsters.

Animals↗
PubMed2000

[Intramasseter hemangiomas: a case report].

Intramuscular hemangiomas are uncommon tumours in the head and neck region, especially in the masseter muscle. This article presents a case of a 10-year-old male treated by surgical excision. The authors review the literature to discuss the clinical characteristics, sex, age, differential diagnosis, surgical approaches, and histology.

Child↗
PubMed2000

[Influences of chronic stress on central nervous systems].

Chronic mild or moderate stress elicits an adaptive change in central nervous systems that function to maintain homeostasis. The principal components of stress response are the extrahypothalamic corticotropin-releasing hormone (CRH) and the locus coeruleus (LC)-norepinephrine (NE) systems. CRH is known to produce various stress-, anxiety- and arousal-associated behaviors in animals. Moreover, CRH causes an increase in the firing rate and activity of tyrosine hydroxylase in the LC, and NE release in LC projection areas. It is thought that chronic inescapable and unpredictable stress can result in a sustained dysregulation of both CRH neuronal activity and LC-NE systems. One may hypothesize that the NE-CRH interaction occurs in the terminal projection of forebrain NE systems, the hypothalamic paraventricular nucleus (PVN), the bed nucleus of the stria terminalis (BNST) and the central nucleus of the amygdala (CeA) where NE stimulates CRH release. Such CRH-NE-CRH feed-forward systems elicit progressive augmentation of stress responsivity with repeated exposure. The beta-adrenergic receptor down-regulation is induced by acute and chronic exposure to moderate and predictable stress, implying an adaptation to stress. However, chronic unpredictable (variable) stress (CVS), a model for depression, up-regulated the beta-AR. In our laboratory, we found that concurrent treatment with the selective serotonin reuptake inhibitor (SSRI) citalopram caused beta-R down-regulation in the frontal cortex of rats treated with CVS for 14 days. As previously reported by the authors, an increase in 5-HT availability plays a role in preserving beta-R down-regulation by NE potentiating agents. In depressed patients, hyperactivation of the CRH-NE systems caused by the CRH-NE feed-forward system is thought to be involved in generating anxiety, sympathetic activation and hyperarousal. Moreover, a decrease in the 5-HT turnover in depressed patients has been reported. Accordingly, it is proposed that an increase in 5-HT availability by SSRI might contribute to normalize beta-R down-regulation as an adaptive regulatory mechanism against excessive CRH-NE neurotransmission under a "stressful" situation.

Animals↗
PubMed2000

Chemoselective oxidative polymerization of m-ethynylphenol by peroxidase catalyst to a new reactive polyphenol.

Enzymatic oxidative polymerization of m-ethynylphenol possessing two reactive groups, phenol and acetylene moieties, was carried out in aqueous methanol under air. Horseradish peroxidase and hydrogen peroxide were used as catalyst and oxidizing agent, respectively. 1H NMR and IR analysis showed that only the phenolic moiety was polymerized to produce the polymer having the ethynyl group in the side chain. The reaction of the monomer using a copper/amine catalyst, a conventional catalyst for oxidative coupling, exclusively produced a diacetylene derivative. From these data, it was found that the peroxidase catalysis induced the chemoselective polymerization of the monomer. The resulting polymer was converted to carbonized polymer in a much higher yield than enzymatically synthesized poly(m-cresol) and is expected to have potential applications as a reactive starting polymer.

Catalysis↗
PubMed1999

Simultaneous measurement of volatile sulfur compounds using ascorbic acid for oxidant removal and gas chromatography-flame photometric detection.

A method for the simultaneous measurement of volatile sulfur compounds (COS, H2S, CS2, CH3SH, DMS) is established with preconcentration and GC-flame photometric detection (FPD). Prior to preconcentration of ambient air, it was necessary to remove SO2, water vapor and atmospheric oxidant. SO2 and water vapor were removed using a glass fiber filter and a cooled PTFE water trap loop, respectively. In order to remove atmospheric oxidant, the efficiency of an ascorbic acid scrubber was examined. It was found that an ascorbic acid scrubber enabled measurement of volatile sulfur compounds without adsorption and reaction loss. The detection limits for COS, H2S, CS2, CH3SH and DMS were 20, 34, 35, 263 and 44 pg of S, respectively.

Air↗
PubMed1999

Dietary soybean protein moderates the deleterious disturbance of lipid metabolism caused by exogenous oxidized cholesterol in rats.

Effects of dietary protein on oxidized cholesterol-induced disturbance of lipid metabolism were examined in 4 week old male Sprague-Dawley rats, using casein and soybean protein as dietary protein source. The rats were given one of the two proteins in 0. 078% cholesterol (control), 0.25% cholesterol or 0.25% oxidized cholesterol mixture (containing 0.078% cholesterol) diets. Dietary oxidized cholesterol, compared to cholesterol, tended to inhibit hepatic sterol biosynthesis in casein-fed rats, whereas this inhibitory action was slightly moderated by intake of soybean protein. As a result, the hepatic 3-hydroxy-3-methylglutaryl-CoA reductase activity was rather higher in the rats fed oxidized cholesterol than in those fed cholesterol in the soybean protein-fed group. The hepatic cholesterol 7alpha-hydroxylase activity tended to be higher in the rats fed oxidized cholesterol than in those fed control diet in the soybean protein-fed group, despite the fact that oxidized cholesterol lowered the hydroxylase activity in the casein-fed group. On the other hand, dietary oxidized cholesterol tended to slightly enhance the hepatic Delta6 desaturase activity in the casein-fed group; however, this observation was not shown in the soybean protein-fed group. Moreover, dietary soybean protein facilitated fecal oxidized cholesterol excretion and simultaneously inhibited the accumulation of oxidized cholesterol in serum and liver. In conclusion, dietary soybean protein alleviated the deleterious actions of exogenous oxidized cholesterol on hepatic cholesterol and linoleic acid metabolism, although these efficacies were not necessarily significant. A great part of these moderations may be exerted by the specific hypocholesterolemic function of soybean protein, such as the stimulation of fecal oxidized cholesterol excretion, the change of hormonal release and modulation of lipoprotein catabolism.

Animals↗
PubMed1999

Percutaneous absorption of biotin in healthy subjects and in atopic dermatitis patients.

The study was designed to test the ability of sequential applications of biotin-containing ointment to increase serum biotin levels. Twenty atopic dermatitis patients (mean age, 20.5 yr) and 11 healthy subjects (mean age, 25.5 yr) volunteered to participate in this study. The diagnosis of atopic dermatitis was established dermatologically. Seven grams per day of ointment containing 0.3% biotin and 1-4 g per day of steroid ointment were both applied sequentially. The healthy subjects applied only biotin ointment. The biotin concentration was determined microbiologically. Before biotin treatment, the average serum biotin level was significantly lower in atopic dermatitis patients than in healthy subjects. The percutaneous application of biotin-containing ointment caused a significant increase in the serum biotin concentration in both healthy subjects (from 41.5 +/- 10.0 to 50.2 +/- 9.2 nmol/L) and in atopic dermatitis patients (from 27.9 +/- 17.4 to 50.7 +/- 21.6 nmol/L), especially in patients whose initial level was low, and also could be effective in regulating the atopic allergic response involving eosinophils. In conclusion, biotin appears to be readily absorbed through both normal and dermatitis-affected human skin.

Absorption↗
PubMed1998

Dietary oxidized cholesterol modulates cholesterol metabolism and linoleic acid desaturation in rats fed high-cholesterol diets.

The interactive effect of high dietary levels of oxidized cholesterol on exogenous cholesterol and linoleic acid metabolism was examined in male 4-wk-old Sprague-Dawley rats given high-cholesterol diets. The rats were pair-fed purified diets free of or containing either 0.5% cholesterol alone or both 0.5% cholesterol and 0.5% oxidized cholesterol mixture (containing 93% oxidized cholesterol) for 3 wk. Hepatic 3-hydroxy-3-methylglutaryl CoA reductase activity was reduced in rats given cholesterol alone or both cholesterol and oxidized cholesterol. However, hepatic cholesterol 7alpha-hydroxylase activity was lowered only when rats were given both cholesterol and oxidized cholesterol, although dietary cholesterol increased this activity. Reflecting this effect, acidic steroid excretion was lowest among the groups of rats given cholesterol and oxidized cholesterol. On the other hand, the activity of hepatic delta6 desaturase, a key enzyme in the metabolism of linoleic acid to arachidonic acid, was increased in rats given both cholesterol and oxidized cholesterol, although dietary cholesterol alone lowered its activity. As a result, the delta6 desaturation index, 20:3n-6 + 20:4n-6/18:2n-6, in liver and serum phospholipids tended to be higher in the group fed both cholesterol and oxidized cholesterol than in the one fed cholesterol alone. Thus, dietary oxidized cholesterol significantly modulated exogenous cholesterol metabolism and promoted linoleic acid desaturation even when it was given at high levels together with a high cholesterol diet.

Animals↗
PubMed1998

Role of macrophages in acute murine cytomegalovirus infection.

It has been recognized that macrophages play an important role in controlling virus infection in experimental animal models. To evaluate the role of macrophages in acute murine cytomegalovirus infection, macrophages in the spleen and the liver were eliminated by an intravenous injection of liposomes containing a cytolytic agent, dichloromethylene diphosphonate. The depletion of macrophages led to a significant increase of virus titer in the spleen and lungs in both susceptible BALB/c and resistant C57BL/6 mice during the first three days after intravenous infection. In the spleen, the increase of virus titer in macrophage-depleted BALB/c mice was much greater than that in NK cell-depleted mice. These results suggest that macrophages contribute to protection mainly by the mechanisms which are independent of NK cells during the first three days after infection. The increase of virus titer in macrophage-depleted C57BL/6 mice was as great as that in NK cell-depleted mice because of the high contribution of NK cells to protection in C57BL/6 mice. In the liver in both strains of mice, the effects of macrophage depletion on virus titer were not as much as those in the spleen and lungs. Furthermore, the local depletion of peritoneal macrophages resulted in a great increase of virus titer in the spleen at three days after intraperitoneal infection. We conclude that macrophages greatly contribute to decreasing the virus load in some organs possibly through either or both intrinsic and extrinsic mechanisms in the early phase of primary infection with murine cytomegalovirus.

Acute Disease↗
PubMed1998

Doppler echocardiographic method to determine early and late diastolic filling volume separately. Validation and relationship between filling velocity and volume.

We devised a pulsed Doppler echocardiographic method of separately calculating early diastolic filling volume (EDFV) and late diastolic filling volume during atrial contraction (LDFV) and observed a relationship between diastolic filling volume and velocity in thirty patients with coronary artery disease. By analysing the transmitral flow velocity curve and mitral valve motion, EDFV and LDFV were measured on the basis of the equality of left ventricular inflow and outflow volumes. The Doppler-determined EDFV and LDFV correlated well with those obtained from the left ventricular filling curve produced by left ventriculography. Angiographic EDFV and LDFV were measured from the time (t)-volume (V) curve, using the t-dV/dt curve to define early and late diastolic phases. A good correlation was found between Doppler and angiographic EDFV (y = -3.0 + 1.0 x, r = 0.98, p = 0.0001, n = 20), Doppler and angiographic LDFV (y = 1.6 + 1.0 x, r = 0.86, p = 0.0001), and also between Doppler and angiographic EDFV/LDFV (y = 0.05 + 0.9 x, r = 0.93, p = 0.0001). EDFV and the peak early diastolic filling velocity were significantly correlated (E velocity; y = 25 + 0.51 x, r = 0.48, p = 0.0068), while LDFV and the peak late diastolic filling velocity during atrial contraction (A velocity) were not. Our results validate the method of calculating EDFV and LDFV separately and suggest that early diastole in the left ventricle has flow volume dependency, but that the late diastole filling velocity during atrial contraction may be regulated by other factors such as increased left atrial contraction.

Adult↗