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Biomedical subjects

M Masuda

Publications and source records attributed to M Masuda.

At least 37 records · Page 2Linked to original sources
PubMed2001

Effect of atorvastatin treatment on lipoprotein lipase mass in the pre-heparin plasma in Japanese hyperlipidemic subjects.

BACKGROUND: Atorvastatin is a recently introduced statin that lowers LDL-cholesterol (LDL-C) and triglycerides more than some of the older statins. METHODS: Twenty-one Japanese hyperlipidemic subjects were treated with atorvastatin (10 mg/day) for 6 weeks. Plasma lipid concentrations and pre-heparin plasma LPL mass before and after oral administration were evaluated using an open crossover trial format. LPL mass in the pre-heparin plasma was measured by a sandwich enzyme immunoassay. RESULTS: Atorvastatin decreased plasma triglyceride (TG) concentration (-21%, p<0.05), as well as plasma total and LDL-cholesterol concentrations. LPL mass in the pre-heparin plasma did not change significantly by this treatment during this period. Both apolipoprotein (apo) B and E decreased considerably (-33%, p<0.001 for apo B; -29% p<0.001 for apo E), while apo A-I concentration did not change. Other clinical parameters such as body mass index, blood pressure, and fasting plasma glucose concentration of these subjects did not change during this treatment. CONCLUSIONS: Atorvastatin is effective in reducing plasma TG, which did not appear to be associated with an increased LPL mass.

Aged↗
PubMed2001

Antibacterial halogenated metabolites from the Malaysian Laurencia species.

Two halogenated C15 acetogenins, named lembyne-A and lembyne-B, have been isolated from an unrecorded Laurencia species collected off the Malaysian waters. Their structures were deduced on the basis of spectroscopic evidence. Previously known elatol and iso-obtusol showed potent antibacterial activity against some marine bacteria.

Anti-Bacterial Agents↗
PubMed2001

Halogenated metabolites with antibacterial activity from the Okinawan Laurencia species.

The chemical compositions of five species of the red algal genus Laurencia from coastal waters of Okinawa Prefecture, Japan, have been investigated. A halogenated C(15) acetogenin, (12E)-lembyne-A, was isolated from L. mariannensis, and a halogenated sesquiterpene, (6R,9R,10S)-10-bromo-9-hydroxy-chamigra-2,7(14)-diene, was first found from L. majuscula as a naturally occurring compound. Laurencia nidifica yielded previously known laurinterol and isolaurinterol. Samples of L. cartilaginea and L. concreta afforded no halogenated metabolites. The structures of these halogenated metabolites as well as their antibacterial activity against some marine bacteria are reported.

Anti-Bacterial Agents↗
PubMed2001

FcgammaRIII b and FcgammaRIIa polymorphism may affect the production of specific NA1 autoantibody and clinical course of autoimmune neutropenia of infancy.

We studied 18 children with autoimmune neutropenia (AIN) to evaluate whether there was a possible relationship between the specificity of granulocyte autoantibodies (anti-NA1,2) and the phenotype of the NA system. Direct granulocyte immunofluorescence test (D-GIFT) was positive in all patients, and indirect granulocyte immunofluorescence test (I-GIFT) was positive in 17 of these 18 patients, respectively. Fourteen of 18 patients showed preferential binding to neutrophils from NA(1+2-) phenotyped donors. Immunoblotting with anti-FcgammaRIIImAb showed that IgG prepared from 7 of 12 patients precipitated both FcgammaRIIIb from NA1 and NA2 neutrophil lysate, whereas the other 5 precipitated only NA1. Patients' IgG did not react with purified FcgammaRIIa. FcgammaRIIIb genotype were NA(1+2-) in 15 of 18 patients and NA(1+2+) in the other 3. FcgammaRIIa type of all patients were (H+R-). These distributions were significantly different from those of healthy Japanese blood donors (n = 608). The genotype of FcgammaRIIIb and FcgammaRIIa may affect the production of neutrophil specific auto-antibodies in AIN of infancy and influence its clinical course.

Age of Onset↗
PubMed2001

Novel halogenated metabolites from the Malaysian Laurencia pannosa.

In connection with our chemotaxonomic studies of Malaysian species of the red algal genus Laurencia, the chemical composition of Laurencia pannosa Zanardini was examined. Two halogenated sesquiterpenoids, named pannosanol (1) and pannosane (2), have been isolated along with a halogenated C15-acetogenin, (3Z)-chlorofucin (3). The structures of these compounds were determined from their spectroscopic data (IR, 1H NMR, 13C NMR, 2D NMR, and MS). Pannosanol and pannosane are novel halometabolites with an unusual rearranged chamigrane framework. Antibacterial activities of these metabolites against marine bacteria are also described.

Anti-Bacterial Agents↗
PubMed2001

Formation of spiroiminodihydantoin nucleoside by reaction of 8-oxo-7,8-dihydro-2'-deoxyguanosine with hypochlorous acid or a myeloperoxidase-H(2)O(2)-Cl(-) system.

Hypochlorous acid (HOCl), generated by myeloperoxidase from H(2)O(2) and Cl(-), is a strong chlorinating and oxidizing agent, playing an important role in host defense and inflammatory tissue injury. As several recent studies have shown that various oxidizing agents including peroxynitrite and singlet oxygen react readily with 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxodGuo) to yield further oxidized products, we have studied the reaction of 8-oxodGuo with reagent HOCl and with a myeloperoxidase-H(2)O(2)-Cl(-) system. When 1 mM 8-oxodGuo was reacted with 0.5 mM HOCl at pH 7.4 and 37 degrees C, two major products were formed. They were identified as the diastereomers of spiroiminodihydantoin deoxyribonucleoside (dSph) on the basis of their identical ESI-MS and UV spectra and HPLC retention times with those of the major reaction products which were reported to be formed in other oxidation systems including potassium monopersulfate plus cobalt (II) chloride, peroxynitrite plus thiol, and type II photosensitization. Under the above reaction conditions, the yield of the diastereomers of dSph was 0.38 mM, with 0.57 mM 8-oxodGuo remaining unreacted. Since the presence of 50% D(2)O, 10 mM sodium azide, or 2% ethanol did not affect the yield of the products, involvement of singlet oxygen and hydroxyl radical in the formation of dSph from 8-oxodGuo with HOCl was ruled out. A 1000-fold excess of dGuo did not inhibit the reaction of 8-oxodGuo with HOCl, indicating that 8-oxodGuo reacts more readily than dGuo with HOCl. dSph was also formed by reaction of 8-oxodGuo with myeloperoxidase in the presence of H(2)O(2) and Cl(-). Our results suggest that formation of dSph from 8-oxodGuo is mediated, possibly via an addition of Cl(+) to, or two-electron oxidation of 8-oxodGuo, with HOCl or the myeloperoxidase-H(2)O(2)-Cl(-) system.

8-Hydroxy-2'-Deoxyguanosine↗
PubMed2001

Successful treatment with cyclosporin A for myelodysplastic syndrome with erythroid hypoplasia associated with T-cell receptor gene rearrangements.

Myelodysplastic syndrome (MDS) with erythroid hypoplasia, a rare form of MDS, has not yet been clearly defined. We report four patients with MDS with erythroid hypoplasia who received immunosuppressive therapy. All were elderly, had severe transfusion-dependent anaemia, morphological evidence of myelodysplasia and a low percentage (3.2-13.6%) of erythroid precursors. Administration of cyclosporin A (CsA) improved their anaemia; all transfusion-dependent patients achieved transfusion-independence. An inverted CD4/8 ratio was seen in three patients who also demonstrated T-cell receptor (TCR)-beta and -gamma gene rearrangements by Southern blotting and clonality by polymerase chain reaction. Treatment with CsA can be an attractive alternative treatment for patients with MDS with erythroid hypoplasia, which may be associated with a clonal abnormality in T cells.

Aged↗
PubMed2001

Identification of endogenous ouabain in culture supernatant of PC12 cells.

OBJECTIVE: Ouabain-like factor (OLF), assayed as ouabain-like immunoreactivity (OLI), is thought to represent an endogenous digitalis-like factor. We found increased plasma OLI during the surgical removal of a pheochromocytoma. The elution volume of the OLI extracted from plasma and the pheochromocytoma tissue was the same as that for authentic ouabain, using reverse phase high-performance liquid chromatography. The present study was performed to characterize OLF from the culture supernatant of a rat pheochromocytoma cell line, PC12 cells. DESIGN: OLI from culture supernatant and chromatographic fractions were assayed by a sensitive enzyme-linked immunosorbent assay for ouabain. PC12 cells, subcultured in RPMI 1640 with 10% horse serum and 5% fetal bovine serum, were washed, and then cultured in Iscove's modified Dulbecco's medium (Life Technologies, Rockville, Maryland, USA) with 0.4% bovine serum albumin (without serum). Progesterone was added to augment the production or secretion of OLI. The conditioned medium was acidified to dissociate the binding protein, and OLI was purified by five steps of octadecylsilane (ODS) column chromatography. The structural identity of this OLI was determined by liquid chromatography and mass spectrometry (LC/MS). RESULTS: OLI in the culture medium increased after addition of progesterone in a dose-dependent manner. The concentration in the culture medium was approximately double of that in homogenized PC12 cells. After five rounds of ODS column chromatography, approximately 100 ng of OLI was purified from 21 of culture supernatant, without fetal calf serum, in the presence of progesterone. The molecular size of purified OLI was found to be identical to authentic ouabain, based on analysis by LC/ MS. CONCLUSION: Mammalian cells originating from a rat pheochromocytoma cell line were found to produce and/or secrete OLF by the addition of progesterone.

Animals↗
PubMed2001

Inhibitory effect of somatostatin on cholecystokinin release is independent of luminal cholecystokinin-releasing factor content in conscious rats.

INTRODUCTION: Exclusion of bile-pancreatic juice from the intestine increases pancreatic secretion via cholecystokinin (CCK) release in conscious rats. Luminal CCK-releasing factor (LCRF), purified from rat intestinal secretions, is an intraluminal regulator of CCK secretion during bile-pancreatic juice diversion. AIMS: Because somatostatin is a potent inhibitor of CCK release and pancreatic secretion, the inhibitory effect of somatostatin on LCRF was examined. METHODOLOGY: Rats were prepared with bile and pancreatic cannulae and two duodenal cannulae and with an external jugular vein cannula. The experiments were conducted without anesthesia. After 1.5-hour basal collection of pancreatic juice with bile-pancreatic juice return, bile-pancreatic juice was diverted for 2 hours, during which time somatostatin (2, 10 nmol/kg/h) was infused intravenously. The rats were killed before and 1 and 2 hours after bile-pancreatic juice diversion. To examine the effect of luminal somatostatin, 50 or 200 nmol/kg/h of somatostatin was infused into the duodenum. The plasma CCK and luminal content of LCRF were measured by specific radioimmunoassays. RESULTS: Bile-pancreatic juice diversion significantly increased pancreatic secretion, plasma CCK, and LCRF levels. Intravenous infusion of somatostatin inhibited CCK release and pancreatic secretion, but not LCRF content. Luminal administration of somatostatin did not show any effect. CONCLUSION: Inhibitory effect of circulating somatostatin on CCK release and pancreatic secretion is independent of LCRF content.

Animals↗
PubMed2001

The Arabidopsis HY2 gene encodes phytochromobilin synthase, a ferredoxin-dependent biliverdin reductase.

Light perception by the plant photoreceptor phytochrome requires the tetrapyrrole chromophore phytochromobilin (P Phi B), which is covalently attached to a large apoprotein. Arabidopsis mutants hy1 and hy2, which are defective in P Phi B biosynthesis, display altered responses to light due to a deficiency in photoactive phytochrome. Here, we describe the isolation of the HY2 gene by map-based cloning. hy2 mutant alleles possess alterations within this locus, some of which affect the expression of the HY2 transcript. HY2 encodes a soluble protein precursor of 38 kD with a putative N-terminal plastid transit peptide. The HY2 transit peptide is sufficient to localize the reporter green fluorescent protein to plastids. Purified mature recombinant HY2 protein exhibits P Phi B synthase activity (i.e., ferredoxin-dependent reduction of biliverdin IX alpha to P Phi B), as confirmed by HPLC and by the ability of the bilin reaction products to combine with apophytochrome to yield photoactive holophytochrome. Database searches and hybridization studies suggest that HY2 is a unique gene in the Arabidopsis genome that is related to a family of proteins found in oxygenic photosynthetic bacteria.

Alleles↗
PubMed2001

Hepatocellular carcinoma: involvement of the internal mammary artery.

PURPOSE: To investigate factors related to the development of internal mammary arteries (IMAs) as feeding arteries of hepatocellular carcinomas (HCCs). MATERIALS AND METHODS: In 30 patients with HCC located in ventral hepatic areas directly beneath the diaphragm, bilateral internal mammary arteriography was performed to explore involvement of the IMA with HCC. The number of previous transcatheter arterial embolizations (TAEs), tumor size, time from initial TAE to IMA angiography, inferior phrenic artery (IPA) involvement with tumor, presence of hepatic artery occlusion, and use of other treatments were compared in groups with and without involvement of the IMA. RESULTS: The group with IMA involvement included 10 patients; the group without involvement, 20 patients. TAE had been performed two to 12 times in the group with involvement and zero to six times in the group without involvement (P =.01). Mean tumor sizes in these two groups were 5.1 and 6.0 cm, respectively; hepatic artery occlusion was noted in nine and zero patients (P =.01) in the two groups. The time from initial TAE to IMA angiography ranged from 3 to 53 months (median, 31.5 months) and from zero to 89 months (median, 0 months) (P =.01). IPA involvement was observed in seven and four patients (P =.015). CONCLUSION: These results strongly suggest that, regardless of tumor size, when HCCs are located in the ventral hepatic areas directly beneath the diaphragm, the IMAs serve as feeding arteries in patients with hepatic artery occlusion caused by repeated TAE.

Aged↗
PubMed2001

Tobacco smoke reduces viability in human lung fibroblasts: protective effect of glutathione S-transferase P1.

Cigarette smoking is thought to be a major risk factor in various lung diseases including lung cancer and emphysema. However, the direct effect of cigarette smoke on the viability of lung-derived cells has not been fully elucidated. In this study, we investigated the viability of human lung fibroblast-derived (HFL1) cells to different concentrations of cigarette smoke extract (CSE). CSE induced apoptosis at lower concentrations (10-25%) and necrosis at higher concentrations (50-100%). We also examined the effects of glutathione S-transferase P1 (GSTP1), one of the xenobiotic metabolizing and antioxidant enzymes in the lung, against the cytotoxicity of CSE. Our results indicated that the level of HFL1 cell death was decreased by transfection with a GSTP1 expression vector and was increased by GSTP1 antisense vector transfection. Therefore, transient overexpression and underexpression of GSTP1 appeared to inhibit and enhance the cytotoxic effects of CSE on HFL1 cells, suggesting that GSTP1 may have protective effects against cigarette smoke in the airway cells.

Apoptosis↗
PubMed2001

The influence of fractional pulse pressure on the outcome of pulmonary thromboendarterectomy.

Although pulmonary thromboendarterectomy is an effective modality for the treatment of chronic thromboembolic pulmonary hypertension (CTEPH), the mortality in patients with severe haemodynamic disease is still high. Recently it was reported that fractional pulse pressure (pulmonary arterial pulse pressure/mean pulmonary arterial pressure) was higher in CTEPH than in primary pulmonary hypertension (PPH). It was hypothesized that fractional pulse pressure might be low in CTEPH with inaccessible distal thrombi and/or secondary pulmonary hypertensive change, resulting to the high operative mortality. To determine the influence of fractional pulse pressure to the outcome of surgery, 32 patients with CTEPH who had thromboendarterectomy between 1985 and 1998 were studied. Pulmonary haemodynamics and fractional pulse pressure were compared between survivors (n=26) and nonsurvivors (n=6) postoperatively. Those parameters in PPH (n=18) and large vessel pulmonary arteritis (n=6) were also analysed. Fractional pulse pressure in CTEPH (1.23+/-0.21) was significantly higher than in PPH (0.93+/-0.22; p=0.0017) and lower than in pulmonary arteritis (1.69+/-0.32; p=0.03). Fractional pulse pressure in survivors (1.26+/-0.21) was significantly higher than in nonsurvivors (1.06+/-0.16; p=0.03). Fractional pulse pressure is a significant predictor for mortality in patients with high pulmonary vascular resistance >1100 dynes.sec.cm(-5). To conclude fractional pulse pressure in addition to pulmonary vascular resistance might be useful in predicting for the outcome of surgery, especially in patients with severe haemodynamic impairment.

Adult↗
PubMed2001

Is PECAM-1 a mechanoresponsive molecule?

Endothelial cells are capable of responding to fluid shear stress, but the molecular mechanism for this biological response remains largely unknown. Our studies indicate that the cell-cell adhesion site is a possible site of flow sensing. PECAM-1, a cell adhesion molecule localized to the interendothelial cell adhesion site, is tyrosine-phosphorylated when endothelial cells are exposed to physiological levels of fluid shear stress. This PE-CAM-1 phosphorylation initiates a signaling cascade leading to ERK activation. Here we review what is known about PECAM-1 tyrosine phosphorylation and suggest a possible role of PECAM-1 in mechanosensing by endothelial cells.

Animals↗
PubMed2001

Increases of calcium and magnesium and decreases of phosphorus and iron with aging in human uterine tubes.

To elucidate compositional changes of the uterine tube by aging, the authors studied age-related changes of elements in human uterine tubes by inductively coupled plasma-atomic emission spectrometry. The uterine tubes were resected postmortem or surgically removed from patients with uterine myoma. It was found that the contents of calcium and magnesium increased progressively with aging in uterine tubes, whereas the contents of phosphorus and iron decreased gradually with aging. The sulfur content of uterine tubes remained constant and independent of aging. Regarding relationships between elements, significant relationships were found between calcium and magnesium contents, between phosphorus and iron contents, between phosphorus and sulfur contents, and between phosphorus and sodium contents in human uterine tubes.

Aged↗
PubMed2001

Effects of nitric oxide on steroidogenesis in porcine granulosa cells during different stages of follicular development.

BACKGROUND: We have previously demonstrated that nitric oxide (NO) inhibits steroidogenesis via a cGMP-independent process, by inhibiting P450 aromatase activity in porcine granulosa cells (PGCs) derived from medium-sized (3--5 mm) ovarian follicles (M-PGC). OBJECTIVE: To determine whether the NO/NO synthase (NOS) system exerts any significant effects on steroidogenesis in PGCs derived from small follicles (<3 mm) (S-PGC) in comparison with those derived from medium follicles. DESIGN AND METHODS: PGCs, namely S-PGC and M-PGC, were incubated with the NO donor, NOC18, and a competitive blocker of NOS, N(3)-monomethyl-l-arginine (LNMMA), either alone or in the presence of FSH (200 ng/ml) or hCG (5 IU/ml). RESULTS: NOC18 significantly (P<0.01--0.001) suppressed basal (unstimulated) and gonadotropin-stimulated estradiol (E2) release from both S-PGC and M-PGC in a 2-h culture. NOC18 significantly (P<0.01--0.001) decreased basal and gonadotropin-stimulated progesterone release from S-PGC, but not from M-PGC. In addition, NOC18 significantly (P<0.05--0.001) inhibited aromatase activity in S-PGC. LNMMA had a significantly (P<0.01--0.001) stimulatory effect on the basal release of E2 and progesterone from M-PGC; however, it had no significant effect on basal steroidogenesis in S-PGC in a 24-h culture. In the presence of gonadotropin, LNMMA significantly (P<0.01--0.001) stimulated the release of E2 and progesterone from both S- and M-PGC, and this stimulatory effect was weaker in S-PGC than in M-PGC. These results demonstrate that NO inhibits E2 secretion by directly inhibiting the aromatase activity in S-PGC, as in M-PGC. It has been shown that the NO system suppresses the differentiation of S-PGC; however, the extent of suppression decreased with the progression of follicular growth. In addition, the activity of NOS in S-PGC was weaker than that in M-PGC. CONCLUSION: We strongly suggest that the NO/NOS system in PGC regulates steroidogenesis differently during different phase of follicular development.

Animals↗
PubMed2001

Marked uptake of technetium-99m pertechnetate by parathyroid adenoma.

We herewith report an unusual case of primary hyperparathyroidism whose parathyroid adenoma strongly accumulated technetium (Tc)-99m pertechnetate. A 41-year-old woman was referred to our department under the tentative diagnosis of primary hyperparathyroidism. Scintigraphy by thallium-201 chloride showed homogeneous uptake in the whole thyroid, whereas Tc-99m image revealed a strong local accumulation in the middle portion of the right thyroidal lobe. Neck exploration revealed a 12x8x5 mm tumor in the posterolateral region of the right thyroidal lobe, the pathology of which was parathyroid adenoma. In addition, a small nodule (8 mm in diameter) with pathological findings revealing follicular adenoma of the thyroid, was found within the medial portion of the right thyroidal lobe. Both lesions were removed by surgery, and a postoperative Tc-99m scintigraphy no longer demonstrated a significant uptake in the right thyroidal lobe. Since the thyroid adenoma was too small to be detected by any scintigraphic study and located much closer to the median line than the site of the marked accumulation of Tc-99m pertechnetate, it was considered very likely that the parathyroid adenoma concentrated Tc-99m. Search of literature revealed that there have been only thirteen cases of parathyroid tumor reported to date which significantly accumulated Tc-99m pertechnetate. The present patient represents another rare case of parathyroid adenoma showing sueh an unusual scintigraphic image.

Adenoma↗