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Biomedical subjects

M Yamaguchi

Publications and source records attributed to M Yamaguchi.

At least 865 records · Page 48Linked to original sources
PubMed1994

Decidua is a possible source of serum mouse soluble interleukin-6 receptor (msIL-6R): gestational profile of serum msIL-6R concentration.

The serum concentration of msIL-6R of 10 weeks old virgin ICR mouse assessed by a RIA was 45.6 +/- 6.6 ng/ml. The serum msIL-6R concentration of the pregnant mouse mated at 10 weeks of age was 41.2 +/- 3.0 ng/ml on day 7 of pregnancy. The serum concentration gradually increased during gestation and reached peak on day 17 of pregnancy (149.1 +/- 13.7 ng/ml). On the third day of the puerperium, the serum msIL-6R concentration of the mother from which the pups had been removed on the day of delivery was decreased to the level of that on day 7 of pregnancy. IL-6R mRNA level in the decidua significantly increased during mid and late gestational stages. msIL-6R was detected in the medium of cultured decidual cells (8.03 +/- 0.28 ng/ml), but not placental cells. Western analysis for msIL-6R using the conditioned medium of the cultured decidual cells resulted in a single band at approximately 45 K. To find out a biological role of msIL-6R during gestation, placental cells were incubated with mIL-6 and msIL-6R, and mPL-I concentration in the medium was assessed by RIA. 2.5 nM mIL-6 did not affect the secretion of mPL-I in placental cells; however, addition of msIL-6R resulted in a significant stimulation of mPL-I secretion. These results suggest that serum msIL-6R, which is likely to be secreted from decidua, may play an important role during gestation.

Analysis of Variance↗
PubMed1994

Expression of hepatic calcium-binding protein regucalcin mRNA is decreased by phenobarbital administration in rats.

The effect of phenobarbital on the expression of calcium-binding protein regucalcin mRNA in rat liver was investigated. The change of regucalcin mRNA levels was analyzed by Northern blotting using liver regucalcin cDNA (0.9 kb of open reading frame). Phenobarbital (4, 8 and 12 mg/ 100 g body weight) was intraperitoneally administered to rats 3 times with 24 h intervals, and the animals were sacrificed by bleeding at 24 h after the last administration. The hepatic regucalcin mRNA levels were markedly reduced by phenobarbital administration. This decrease was about 50% of control level with the 12 mg/100 g dose. Moreover, the hepatic regucalcin concentration was significantly decreased by the administration of phenobarbital (12 mg/100 g), although the serum regucalcin concentration was not altered appreciably. Meanwhile, serum transaminases (GOT and GPT) activities were not increased by the administration of phenobarbital (4 and 12 mg/100 g). The present study demonstrates that the expression of hepatic regucalcin mRNA is decreased by phenobarbital administration in rats, suggesting that regucalcin does not have a role in drug metabolism related to phenobarbital.

Alanine Transaminase↗
PubMed1994

Activation mechanism of NADPH oxidase by SDS in intact guinea pig neutrophils.

It is well known that sodium dodecyl sulfate (SDS) activates NADPH oxidase in a cell-free system independently of protein kinase C (PKC). However, in intact neutrophils, direct evidence has never been presented to show that O2- production by SDS is actually due to the NADPH oxidase activation observed in the cell-free system. So, in this paper, we investigated the activation mechanism by SDS in intact guinea pig neutrophils. We previously reported that hypotonic treatment reversibly enhanced O2- production stimulated by PKC activators in intact neutrophils (M. Hiura et al., 1991, Arch. Biochem. Biophys. 291, 31-37). In this paper, SDS also significantly stimulated O2- production in the intact cells under the hypotonic condition. This enhancement was gradual and was PKC inhibitor resistant. Furthermore, phosphorylation of the 46-kDa protein, one of cytosolic activation factors, was not detected by autoradiography of two-dimensional electrophoresis. Translocation of cytosolic activation factors was demonstrated by a decrease in the activity of the factors remained in the cytosol. In the presence of SDS, addition of 1-oleoyl-2-acetylglycerol, a PKC activator, further enhanced O2- production and translocation of the cytosolic activation factors. On the other hand, SDS remarkably increased membrane fluidity in intact neutrophils as well as in the cell-free system. These results indicate that activation of NADPH oxidase by SDS in intact neutrophils seems to be partly due to the same mechanism observed in cell-free activation, and that SDS alone slightly activates the oxidase and other stimulation, such as hypotonic and/or PKC activator treatments, is required for significant activation. The increase in the membrane fluidity may be one of the activation mechanisms of NADPH oxidase by SDS.

Animals↗
PubMed1994

Transforming growth factor-beta 1 post-transcriptionally inhibits mouse growth hormone releasing factor secretion in placenta.

The aim of this study was to investigate whether TGF-beta 1 regulates mouse GHRF secretion by primary cultures of placental cells from day 12 of pregnancy. Ten ng/ml TGF-beta 1 significantly inhibited mouse GHRF secretion by the third day of culture. The lowest concentration of TGF-beta 1 that significantly inhibited mouse GHRF secretion was 1 ng/ml. The inhibitory effect of TGF-beta 1 on mouse GHRF secretion was completely eliminated by addition of an anti-TGF-beta 1 antibody. Steady-state levels of mouse GHRF mRNA as assessed by Northern analysis was not reduced by incubation of placental cells from day 12 of pregnancy with 10 ng/ml TGF-beta 1 for 5 days. Both placenta and decidua expressed TGF-beta 1 mRNA, and the level of TGF-beta 1 mRNA in decidua increased during gestation while the level of TGF-beta 1 mRNA was constant throughout gestation. These findings suggest that TGF-beta 1 is one of the potent regulators of mouse GHRF secretion and that TGF-beta 1 regulates mouse GHRF secretion in an autocrine or paracrine manner in the mouse placenta in vivo.

Animals↗
PubMed1994

Simultaneous high-performance liquid chromatographic determination of 6 beta-hydroxycortisol and cortisol in urine with fluorescence detection and its application for estimating hepatic drug-metabolizing enzyme induction.

A simple and sensitive high-performance liquid chromatographic method is described for the simultaneous determination of 6 beta-hydroxycortisol (6 beta-OHF) and cortisol (F) in urine. Urine (1 ml) containing fludrocortisone as the internal standard is extracted with ethyl acetate. The extract is washed successively with sodium hydroxide solution and water, and subsequently dried under a stream of nitrogen. The residue is redissolved in methanol. The 6 beta-OHF, F and fludrocortisone in the methanol solution are oxidized by cupric acetate and the resulting glyoxal compounds are converted into fluorescent derivatives with 1,2-diamino-4,5-methylenedioxybenzene (DMB). The DMB derivatives of the corticosteroids are separated within 70 min on a reversed-phase column, L-Column ODS, using stepwise elution with methanol-acetonitrile-0.5 M ammonium acetate and detected fluorimetrically at 350 nm (excitation) and 390 nm (emission). The lower limits of detection for 6 beta-OHF and F are 1.8 pmol (680 pg) and 2.4 pmol (950 pg)/ml urine (0.6 pmol and 0.8 pmol/100 microliters injection volume), respectively, at a signal-to-noise ratio of 3. This method can be applied to the determination of urinary 6 beta-OHF, and the ratio of 6 beta-OHF to F in humans and in rhesus monkeys treated orally with phenobarbital as a hepatic drug-metabolizing enzyme inducer.

Administration, Oral↗
PubMed1994

High-performance liquid chromatographic determination of phenylephrine in human serum using column switching with fluorescence detection.

A method for the determination of total phenylephrine (free plus conjugated) in human serum was developed using column-switching high-performance liquid chromatography (HPLC) with fluorescence detection. After serum was deproteinized with acetonitrile, the conjugated phenylephrine was hydrolyzed with diluted hydrochloric acid. The solution was evaporated to dryness. The reconstituted residue was analyzed with HPLC using a heart-cut technique. Good recoveries of the analytes from spiked human serum samples were obtained with small coefficients of variation. A good linear response was obtained for the concentration range 5-500 ng/ml. The lower limit of quantitation for phenylephrine in human serum was 5 ng/ml. The method was applied to the determination of phenylephrine in human serum after oral administration of phenylephrine hydrochloride.

Chromatography, High Pressure Liquid↗
PubMed1994

Sensitive high-performance liquid chromatographic determination of chlorpheniramine in human serum using column switching.

A sensitive method for the determination of chlorpheniramine in human serum was developed using column-switching high-performance liquid chromatography (HPLC) with ultraviolet detection at 210 nm. The analyte was extracted with diethyl ether from alkalinized serum. After evaporation of the organic layer, the reconstituted residue was analyzed by HPLC using a heart-cut technique. Good recoveries of the analyte from spiked human serum samples were obtained with a coefficient of variation below 7%. A good linear response was obtained for the concentration range 0.5-50 ng/ml, with a correlation coefficient higher than 0.999. The lower limit of quantitation for chlorpheniramine in human serum was 0.5 ng/ml. The method was satisfactorily applied to the determination of chlorpheniramine in human serum after oral administration of chlorpheniramine maleate.

Administration, Oral↗
PubMed1994

High-performance liquid chromatographic determination of busulfan in human serum with on-line derivatization, column switching and ultraviolet absorbance detection.

A high-performance liquid chromatographic (HPLC) method is described for the determination of busulfan in human serum using on-line derivatization and column switching. Busulfan was extracted from serum with a mixture of diethyl ether and dichloromethane. After the evaporation of the organic layer, the reconstituted residue was injected into the HPLC system and busulfan was derivatized with sodium diethyldithiocarbamate on the first short column. The back-flushed derivative was then separated on the second column. Finally, after column switching, the heart-cut fraction containing the derivative was further analysed on the third column and monitored with ultraviolet absorbance detection at 278 nm. The lower limit of quantitation in serum was 10 ng/ml.

Busulfan↗
PubMed1994

Lipopolysaccharide primes human basophils for enhanced mediator release: requirement for plasma co-factor and CD14.

Lipopolysaccharide (LPS) is known to enhance IgE-mediated basophil degranulation. Recently, the complex of LPS and plasma LPS-binding protein(LBP) has been shown to induce secretory response via CD14 in monocytes and neutrophils. In the current study, we observed that the sensitivity to LPS of basophils was increased to 100-fold by co-incubation with plasma. LPS promptly completed its effect and amplified degranulation by stimuli bypassing IgE-receptors. Treatment with anti-CD14 completely abolished the priming effect of LPS. These results indicate that the priming effect of LPS on basophil mediator release is mediated via CD14, and that plasma co-factor, possibly identical to LBP, potentiates this reaction.

Acute-Phase Proteins↗
PubMed1994

Inhibitory effect of zinc compounds on osteoclast-like cell formation in mouse marrow cultures.

The effect of zinc compounds on osteoclast-like cell formation in mouse marrow culture in vitro was investigated. The bone marrow cells were cultured for 7 days in alpha-minimal essential medium containing a well-known bone resorbing agent [1,25-dihydroxyvitamin D3, parathyroid hormone (1-34), interleukin-1 alpha or prostaglandin E2]. Osteoclast-like cell formation was estimated by staining for tartrate-resistant acid phosphatase (TRACP), a marker enzyme of osteoclasts. The presence of 1,25-dihydroxyvitamin D3 (10(-8) M), parathyroid hormone (10(-8) M), interleukin-1 alpha (50 U/mL) or prostaglandin E2 (10(-6) M) induced a remarkable increase in osteoclast-like multinucleated cells. These increases were inhibited by the presence of zinc sulfate or zinc-chelating dipeptide (beta-alanyl-L-histidinato zinc; AHZ) in the concentration range of 10(-8) to 10(-5) M. The inhibitory effect of AHZ (10(-8) and 10(-7) M) was more intensive than that of zinc sulfate. Furthermore, the presence of Ni2+, Cu2+, Mn2+ or Co2+ (10(-7) and 10(-6) M) did not have an effect on parathyroid hormone (10(-8) M)-induced osteoclast-like cell formation. The present study clearly demonstrates that zinc compounds have a potent inhibitory effect on osteoclast-like cell formation in mouse marrow culture.

Acid Phosphatase↗
PubMed1994

[A study on the pathogenesis of hyporeninemia in diabetics].

Hyporeninemic hypoaldosteronism has mainly been described in patients with diabetes mellitus. In order to elucidate the mechanisms of hyporeninemia in diabetic patients, the author studied the response of active renin concentration (ARC) and inactive renin concentration (IRC) to the administration of captopril or sodium depletion in patients with diabetes mellitus and glomerulonephritis and in normal subjects. The diabetic patients were separated into four groups: Group 0, diabetic patients without neuropathy or nephropathy; Group I, those with neuropathy without nephropathy; Group II, those without neuropathy with nephropathy; Group III, those with neuropathy and nephropathy. Diabetic patients with some complications had slightly lower plasma active renin levels than those without complications. The mean increase in plasma active renin after captopril (delta ARC) and sodium depletion was lower in group I than in group 0, and there was no difference between group II and group 0. There was no correlation between delta ARC and creatinine clearance (Ccr) in diabetes mellitus. Plasma prorenin was higher in group I than in group 0, and there was no difference between group II and group 0. No significant change of prorenin after captopril was observed in all groups, but the mean increase in plasma inactive renin after sodium depletion was slightly higher in groups I and III than in groups 0 and II. ARC/IRC was significantly lower in group I than in group 0, and there was no difference between group II and group 0. There was no correlation between ARC/IRC and Ccr in diabetes mellitus, but significant correlation between ARC/IRC and postural change in systolic blood pressure. In three diabetic patients with hyporeninemic hypoaldosteronism, the postural fall in systolic blood pressure was significant, and ARC/IRC was significantly low, but IRC was not high. These results suggest that autonomic dysfunction is a major factor in an impairment of the processing of prorenin to active renin in diabetic patients, and severe autonomic dysfunction may impair the biosynthesis of prorenin in patients with hyporeninemic hypoaldosteronism.

Adult↗
PubMed1994

Tumor necrosis factor-alpha (TNF-alpha) inhibits expression of mouse placental lactogen-II through TNF-alpha type-I but not type-II receptor.

The aim of this study was to determine whether TNF-alpha inhibits mPL-II secretion through TNF-RI or TNF-RII, and to investigate the gestational profile of TNF-RI and TNF-RII gene expression. The mouse trophoblast cells from day 12 pregnancy were cultured with or without agonistic polyclonal antibodies directed against the individual TNF-alpha receptors, and mPL-II secretion in the medium was assessed by RIA. Anti-TNF-RI antibody significantly inhibited the mPL-II secretion in a dose- and time-dependent manner, but anti-TNF-RII antibody did not. Moreover, the TNF-RII antibody did not influence the inhibitory effect of the TNF-RI antibody on mPL-II secretion. TNF-RI antibody inhibited the mPL-II gene expression by Northern blot analysis. Amount of the gene expression of TNF-RI in the second half of pregnancy was higher than those in the first half of pregnancy both in vitro and in vivo, although the gene expression of TNF-RII was not detectable by Northern blot analysis using poly(A)+RNA. These results suggest that TNF-RI is a main receptor for TNF-alpha in mouse placenta and that TNF-alpha may have an important role in regulating mPL-II secretion after midpregnancy.

Animals↗
PubMed1994

Molecular cloning and nucleotide sequence of the complementary DNA for penicillolysin gene, plnC, and 18 kDa metalloendopeptidase gene from Penicillium citrinum.

A full-length cDNA encoding the penicillolysin, an 18 kDa metalloendopeptidase from Penicillium citrinum, was cloned. Analysis of the 1284 base pair nucleotide sequence of the cDNA revealed a single open reading frame coding for 351 amino acid residues. The coding region of penicillolysin gene, plnC, occupies 1053 base pairs of the cDNA. The sequence consists of a putative 19-residue signal sequence, a 155-residue propeptide segment, and the 177-residues of penicillolysin with a molecular weight of 18,529. The deduced primary structure of penicillolysin is unique and the enzyme is a member of a new metalloendopeptidase family. Two histidine residues, His-128 and His-132, and glutamic acid residue, Glu-65 in penicillolysin were assumed to correspond to zinc ligands in the homologous thermolysin.

Amino Acid Sequence↗
PubMed1994

Clinical importance of extraordinary integration patterns of human T-cell lymphotropic virus type I proviral DNA in adult T-cell leukemia/lymphoma.

The proviral DNA of human T-cell lymphotrophic virus type I (HTLV-I) is known to be integrated monoclonally in the malignant cells of adult T-cell leukemia/lymphoma (ATL), which is a peripheral T-cell malignancy caused by this virus. We studied the relationship between the integration patterns of HTLV-I and clinical characteristics in 89 patients with ATL. The proviral DNA of HTLV-I was examined by the standard Southern blot analysis using the endonucleases EcoRI and Pst I. One clear band of greater than 9 kb was detected in most of the patients (83 case) when cellular DNA was digested with EcoRI. On the other hand, extraordinary integration patterns of HTLV-I proviral DNA were detected in 6 patients; 3 of them showed two bands, while the other 3 showed one band smaller than 9 kb. When cellular DNA was digested with PstI, the band patterns of these patients were quite different from those of typical patients. The patients with the extraordinary integration patterns had clinical characteristics dissimilar to those of the other 83 patients with the ordinary integration pattern. The patients with two bands by EcoRI digestion always had severe hypoxemia with extremely high levels of serum lactate dehydrogenase at first presentation and showed peculiar organ infiltrations, such as retina and muscle, which were less frequent in the other ordinary 83 patients. They all died within 8 months after the onset. In contrast, the patients with one smaller band by EcoRI digestion always had small and mature T lymphocytes with bilobulated nuclei without lymphadenopathy and showed a favorable clinical course, which was uncommon in the ordinary cases. They were alive 20 to 38 months after diagnosis. Rearranged bands of the T-cell receptor gene were detected in all patients with unusual integration. These findings indicate that the integration patterns of HTLV-I proviral DNA have a clinical implication and may be one of the explanations for heterogeneity in the behavior of this disease.

DNA, Viral↗
PubMed1994

Effect of beta-alanyl-L-histidinato zinc on protein components in osteoblastic MC3T3-El cells: increase in osteocalcin, insulin-like growth factor-I and transforming growth factor-beta.

The effect of beta-alanyl-L-histidinato zinc (AHZ) on protein components in osteoblastic MC3T3-E1 cells was investigated. Cells were cultured for 3 days at 37 degrees C in CO2 incubator in plastic dishes containing alpha-modified minimum essential medium supplemented with 10% fetal bovine serum. After the cultures, the medium was exchanged for that containing 0.1% bovine serum albumin plus various concentrations of AHZ or other reagents, and the cells were cultured further 3 or 6 days. The homgenate of cells was analyzed with SDS-polyacrylamide gel electrophoresis (SDS-PAGE). The presence of AHZ (10(-7) to 10(-5) M) caused an appreciable increase of many protein components in cells. Especially, the 67 killo-dalton (kDa) and 44 kDa proteins which are the major components from control cells were clearly increased by the presence of AHZ. Furthermore, the concentrations of osteocalcin, insulin-like growth factor-I and transforming growth factor-beta in the culture medium secreted from osteoblastic cells were markedly increased by the presence of AHZ (10(-6) and 10(-5) M). The effect of AHZ was a greater than that of zinc sulfate (10(-6) and 10(-5) M). The present findings suggest that AHZ can increase many proteins which are involved in the stimulation of bone formation and cell proliferation in osteoblastic cells.

Carnosine↗
PubMed1994

Expression of calcium-binding protein regucalcin mRNA in rat liver is stimulated by calcitonin: the hormonal effect is mediated through calcium.

The involvement of a hypocalcemic hormone calcitonin (CT) in the expression of hepatic Ca(2+)-binding protein regucalcin mRNA was investigated. The change of regucalcin mRNA levels was analyzed by Northern blotting using liver regucalcin complementary DNA (0.9 kb). A single oral administration of calcium chloride (100 mg Ca/100 g body weight) to rats induced a remarkable increase in the serum calcium concentration and a corresponding elevation of the liver calcium content during 120 min after the administration. Thyroparathyroidectomy (TPTX) did not cause a significant increase in the liver calcium content after calcium administration. Hepatic regucalcin mRNA level was markedly elevated by calcium administration; the level was about 180% of controls at 60 min after the administration. This increase was completely abolished by TPTX. A single subcutaneous administration of CT (synthetic eel CT; 25-100 MRC mU/100 g) to TPTX rats received oral administration of calcium (100 mg/100 g) produced a remarkable increase in hepatic regucalcin mRNA levels; the level was about 280% of controls with the dose of 25 MRC mU CT/100 g. The present finding suggests that the expression of hepatic mRNA is stimulated by CT, and that the hormonal effect is mediated through Ca2+ in rat liver.

Animals↗
PubMed1994

Activating effect of regucalcin on (Ca(2+)-Mg2+)-ATPase in rat liver plasma membranes: relation to sulfhydryl group.

The activating mechanism of regucalcin, a calcium-binding protein isolated from rat liver cytosol, on (Ca(2+)-Mg2+)-ATPase in the plasma membranes of rat liver was investigated. (Ca(2+)-Mg2+)-ATPase activity was markedly increased by a sulfhydryl (SH) group protecting reagent dithiothreitol (DTT; 2.5 and 5 mM as a final concentration), while the enzyme activity was significantly decreased by a SH group modifying reagent N-ethylmaleimide (NEM; 0.5-5 mM). The effect of DTT (5 mM) to increase the enzyme activity was clearly blocked by NEM (5 mM). Regucalcin (0.25-1.0 microM) significantly increased (Ca(2+)-Mg2+)-ATPase activity. This increase was completely blocked by NEM (5 mM). Meanwhile, digitonin (0.04%), which can solubilize the membranous lipids, significantly decreased (Ca(2+)-Mg2+)-ATPase activity. Digitonin did not have an effect on the DTT (5 mM)-increased enzyme activity. However, the effect of regucalcin (0.25 microM) increasing (Ca(2+)-Mg2+)-ATPase activity was entirely blocked by the presence of digitonin. The present results suggest that regucalcin activates (Ca(2+)-Mg2+)-ATPase by the binding to liver plasma membrane lipids, and that the activation is involved in the SH groups which are an active site of the enzyme.

Animals↗