Biomedical subjects

H Masuda

Publications and source records attributed to H Masuda.

At least 127 records · Page 7Linked to original sources

PubMed1999

Identification of potent odorants in Japanese green tea (Sen-cha).

Application of aroma extract dilution analysis using the volatile fraction of a Japanese green tea (Sen-cha) sample resulted in the detection of 36 odor-active peaks with flavor dilution (FD) factors between 10 and 5000. Thirty-six potent odorants were identified from 36 odor-active peaks by gas chromatography/mass spectrometry (GC/MS) and/or the multidimensional GC/MS (MDGC/MS) system. Among these components, 4-methoxy-2-methyl-2-butanethiol (meaty), (Z)-1, 5-octadien-3-one (metallic), 4-mercapto-4-methyl-2-pentanone (meaty), (E,E)-2,4-decadienal (fatty), beta-damascone (honey-like), beta-damascenone (honey-like), (Z)-methyl jasmonate (floral), and indole (animal-like) showed the highest FD factors. Therefore, these odorants were the most important components of the Japanese green tea odor. In addition, 4-methoxy-2-methyl-2-butanethiol, 4-mercapto-4-methyl-2-pentanone, methional, 2-ethyl-3, 5-dimethylpyrazine, (Z)-4-decenal, beta-damascone, maltol, 5-octanolide, 2-methoxy-4-vinylphenol, and 2-aminoacetophenone were newly identified compounds in the green tea.

Gas Chromatography-Mass Spectrometry↗

PubMed1999

Synchronization of somatic embryogenesis at high frequency using carrot suspension cultures: model systems and application in plant development.

Materials and methods for the high frequency induction and synchronous somatic embryogenesis from cultured cells of higher plants are described, using carrot suspension cultures as a model system of higher plants. The following four synchronous systems of somatic embryogenesis, which were established in our laboratories, are reported: (1) Somatic embryogenesis from single cells. a) Small spherical single cells, obtained from suspension cultures in the presence of 2,4-D, zeatin and mannitol by sieving, density gradient centrifugation in Percoll solutions and manual picking up, form embryogenic cell clusters, which differentiate to embryos at high frequency, when embryogenic cell clusters are transferred to a medium lacking 2,4-D. b) Explants of hypocotyls of regenerated plantlets from somatic embryos were cultured after treatment with 2,4-D for 12-24 h, and then transferred into a fresh medium lacking 2,4-D. Single cells are released from hypocotyl explants and differentiated into embryos at high frequency. In this system, a large number of single cells and embryogenic cells can be collected. (2) Somatic embryogenesis from embryogenic cell clusters, which are obtained from suspension cultures by sieving, density gradient centrifugation in Ficoll solutions, and subsequent centrifugation at a low speed, differentiate synchronously to globular embryos at high frequency. Plantlets are formed from globular embryos. (3) Embryogenic cell clusters obtained according to the procedure described in (2) are cultured at cell densities of 2x10(3) cell clusters ml(-1). Globular embryos differentiate to torpedo-shaped embryos and subsequently to plantlets at high frequency when they are cultured at densities below 150 globular embryos ml(-1).

Daucus carota↗

PubMed1999

Ischemia- and cytokine-induced mobilization of bone marrow-derived endothelial progenitor cells for neovascularization.

Endothelial progenitor cells (EPCs) have been isolated from circulating mononuclear cells in human peripheral blood and shown to be incorporated into foci of neovascularization, consistent with postnatal vasculogenesis. We determined whether endogenous stimuli (tissue ischemia) and exogenous cytokine therapy (granulocyte macrophage-colony stimulating factor, GM-CSF) mobilize EPCs and thereby contribute to neovascularization of ischemic tissues. The development of regional ischemia in both mice and rabbits increased the frequency of circulating EPCs. In mice, the effect of ischemia-induced EPC mobilization was demonstrated by enhanced ocular neovascularization after cornea micropocket surgery in mice with hindlimb ischemia compared with that in non-ischemic control mice. In rabbits with hindlimb ischemia, circulating EPCs were further augmented after pretreatment with GM-CSF, with a corresponding improvement in hindlimb neovascularization. There was direct evidence that EPCs that contributed to enhanced corneal neovascularization were specifically mobilized from the bone marrow in response to ischemia and GM-CSF in mice transplanted with bone marrow from transgenic donors expressing beta-galactosidase transcriptionally regulated by the endothelial cell-specific Tie-2 promoter. These findings indicate that circulating EPCs are mobilized endogenously in response to tissue ischemia or exogenously by cytokine therapy and thereby augment neovascularization of ischemic tissues.

Animals↗

PubMed1999

Accelerated intimal hyperplasia and increased endogenous inhibitors for NO synthesis in rabbits with alloxan-induced hyperglycaemia.

1. We examined whether endogenous inhibitors of NO synthesis are involved in the augmentation of intimal hyperplasia in rabbits with hyperglycaemia induced by alloxan. 2. Four weeks after the endothelial denudation of carotid artery which had been performed 12 weeks after alloxan, the intimal hyperplasia was greatly augmented with hyperglycaemia. The degree of hyperplasia was assessed using three different parameters of histopathological findings as well as changes in luminal area and intima: media ratio. 3. There were positive and significant correlations between intima:media ratio, plasma glucose, and concentrations of N(G)-monomethyl-L-arginine (L-NMMA) and N(G), N(G)-dimethyl-L-arginine (ADMA) in endothelial cells, that is, the intima:media ratio became greater as plasma glucose and endothelial L-NMMA and ADMA were increased. Furthermore, endothelial L-NMMA and ADMA were increased in proportion to the increase in plasma glucose. 4. In contrast, there were inverse and significant correlations between cyclic GMP production by carotid artery strips with endothelium and plasma glucose, between cyclic GMP production and endothelial L-NMMA and ADMA, and between the intima:media ratio and cyclic GMP production. 5. Exogenously applied L-NMMA and ADMA inhibited cyclic GMP production in a concentration-dependent manner. IC50 values were determined to be 12.1 microM for the former and 26.2 microM for the latter. The cyclic GMP production was abolished after the deliberate removal of endothelium from the artery strips. 6. These results suggest that the augmentation of intimal hyperplasia with hyperglycaemia is closely related to increased accumulation of L-NMMA and ADMA with hyperglycaemia, which would result in an accelerated reduction in NO production/release by endothelial cells.

Alloxan↗

PubMed1999

Possible misinterpretation on computed tomography of left inferior vena cava as retroperitoneal lymph node metastasis: a report of two cases.

PURPOSE: We report on two cases of retroperitoneal lymph node metastasis of testicular cancer with left inferior vena cava. METHODS/RESULTS: A 25-year-old man with a left testicular cancer with pulmonary and retroperitoneal lymph node metastases received three courses of VIP (etoposide, ifosfamide and cisplatinum) chemotherapy. Subsequent abdominal computed tomography (CT) revealed round lesions enhanced with contrast agent on both sides of the aorta inside the degenerated lymphadenopathy. These lesions were regarded as a duplicated inferior vena cava (IVC) and this was confirmed at retroperitoneal lymph node dissection. The second case is of a 21-year-old man with a left testicular cancer with pulmonary, liver and widespread lymph node metastases. Subsequent to a course of VIP chemotherapy, super high-dose chemotherapy was administered. Abdominal CT revealed a round mass enhanced with contrast agent on the left side of the aorta adjacent to the degenerated lymphadenopathy, which was regarded as the transposed left IVC and this was confirmed at lymph node dissection. CONCLUSIONS: In both cases, initial CT failed to detect the lesions as the left IVC and there was a possibility for the misinterpretation of such venous anomalies with residual lymphadenopathy.

Adult↗

PubMed1999

Effectiveness of preoperatively obtained autologous platelet concentrates in open heart surgery.

BACKGROUND: Autologous blood components have been widely introduced in open heart surgery. However, the effectiveness of autologous platelet products remains controversial. METHODS: Autologous platelet concentrates (PC) were collected from patients (n = 35) scheduled for primary valvular heart surgery 1 to 3 days before the operation and were transfused immediately after cardiopulmonary bypass. Blood loss and platelet-related factors were compared with the control patients who had no PC (n=35). RESULTS: There were no serious complications in harvesting, preservation, and transfusion of autologous PC. The maximal platelet aggregation response significantly improved after its transfusion and tended to be higher with autologous PC stored 1 day than with ones stored 2-3 days. Activation of coagulation and fibrinolytic factors did not significantly differ between the groups. Postoperative blood loss was significantly less in autologous PC group, and seemed to have a negative correlation with platelet aggregation response. CONCLUSIONS: Autologous PC can be safely prepared and are clinically effective in reduction of postoperative blood loss in open heart surgery.

Aged↗

PubMed1999

Gestational changes in endothelin-1-induced receptors and myometrial contractions in rat.

The present experiments were performed to characterize the gestational changes in endothelin (ET)-1-induced myometrial contractions and ET receptors in rat. ET-1-induced contractions were composed of two types: increases in resting tone and rhythmic contractions. The increase in resting tone was decreased at 7 days of gestation, but increased at 20 days. The increase in amplitude and frequency of rhythmic contractions remained unchanged during days 7-14 of gestation. Continuous rhythmic contractions were not produced by ET-1 near the term. Both contractions were inhibited by the antagonists BQ 123 and Ro 46-2005 but not by RES 701-1 or BQ 788. In binding studies, total binding sites of [1251]-ET-1 were unchanged, however higher affinity binding sites appeared during pregnancy in addition to the lower affinity sites. The specific [125I]-ET-1 binding in non-pregnant and pregnant myometrium was completely inhibited by unlabelled ET-1 and Ro 46-2005. In contrast, the proportion which was inhibited by BQ 123 was decreased during pregnancy. In conclusion, characteristic gestational changes were the augmentation of ET-1-induced increased resting tone near term, and the appearance of high affinity ET-1 binding sites and an increase in BQ 123-resistant ET-1 binding sites during pregnancy. Further investigations are needed to understand the physiological role of these changes.

Animals↗

PubMed1999

Detection of two novel mutations (nt2762, exon 2, CAG to TAG, and nt2483 or 2484, exon 2, +A) in individuals with congenital type I antithrombin deficiencies.

Genetic analyses were performed on two Japanese kindreds with congenital type I antithrombin deficiency causing recurrent thrombosis. The seven exons and flanking intron regions of the antithrombin gene were amplified by polymerase chain reaction followed by direct nucleotide sequencing. In case 1, one novel nonsense mutation, CAG to TAG at codon 100, nucleotide 2762, in exon 2, was detected. In case 2, one novel minor insertion, AT to AAT at codon 7, nucleotide 2483 or 2484, in exon 2, was detected, leading to a frameshift which resulted in a stop codon TGA at codon 32.

Adolescent↗

PubMed1999

Adaptive remodeling of internal elastic lamina and endothelial lining during flow-induced arterial enlargement.

Gaps in the internal elastic lamina (IEL) have been observed in arteries exposed to high blood flow. To characterize the nature and consequences of this change, blood flow was increased in the carotid arteries of 56 adult, male, Japanese white rabbits by creating an arteriovenous fistula between the common carotid artery and the external jugular vein. The common carotid artery proximal to the arteriovenous fistula was studied at intervals from 1 hour to 8 weeks after exposure to high flow. In the controls, the IEL showed only the usual, small, physiological holes, 2 to 10 microm in diameter. At 3 days, some of the holes in the IEL had become enlarged, but they could not be detected by scanning electron microscopy, despite manifest endothelial cell proliferation. At 4 days, gaps in the IEL appeared as small, luminal surface depressions, 15 to 50 microm wide. At 7 days, the gaps in the IEL had enlarged and formed circumferential, luminal depressions occupying 15+/-5% of the lumen surface. Endothelial cell proliferation persisted in the gaps while proliferative activity decreased where the IEL remained intact. At 4 weeks, as the artery became elongated and dilated, the gaps in the IEL widened as intercommunicating circumferential and longitudinal luminal depressions occupying 64+/-5% of the lumen surface. At 8 weeks, the rate of elongation and dilatation of the artery slowed and the widening of the gaps in the IEL diminished. Endothelial cells covered the gaps throughout. We conclude that flow-induced arterial dilatation is accompanied by an adaptive remodeling of the intima. The gaps in the IEL permit an increase in lumen surface area while endothelial cell proliferation assures a continuous cell lining throughout.

Animals↗

PubMed1999

Sudden death with malignant hemangioendothelioma originating in the pericardium--a case report.

The authors report a rare case of a malignant hemangioendothelioma (MH) originating in the pericardium. In this case, a metastatic skin lesion was found first, and subsequently the existence of a primary cardiac lesion was confirmed. Generally, primary cardiac tumors grow slowly, and the prognosis of MH is relatively good. In this case, however, the patient died suddenly during the creation of a pericardial window for drainage. An autopsy showed that the MH originated from a pericardial lesion in the right atrium.

Death, Sudden↗

PubMed1999

ATZ1993, an orally active and novel nonpeptide antagonist for endothelin receptors and inhibition of intimal hyperplasia after balloon denudation of the rabbit carotid artery.

The present experiments were designed to investigate the effect of ATZ1993 [3-carboxy-4,5-dihydro-1-[1-(3-ethoxyphenyl)propyl]-7-(5-pyrimidinyl)met hoxy-[1H]-benz[g]indazole] on the intimal hyperplasia after balloon endothelial denudation of the rabbit carotid artery. ATZ1993 inhibited the specific [125I]endothelin (ET)-1 binding not only to ET-receptor subtype A (ET(A)) with a pKi value of 8.69+/-0.02, but also to ET-receptor subtype B (ET(B)) with a pKi value of 7.20+/-0.03. Counterscreening in the binding assay (30 different receptors) confirmed that ATZ1993 had a high selectivity for ET receptors. Increases in intima:media ratio and DNA content in the vessel wall were significantly (P < 0.005) inhibited by ATZ1993 in a daily dose of 30 mg x 200 ml(-1) x kg(-1) for 1 week before and 6 weeks after balloon denudation. Inhibition of the intimal hyperplasia with ATZ1993 was determined as approximately 77% for increases in intima:media ratio and DNA content. Plasma concentrations of ATZ1993 ranged between 121.6+/-26.6 and 131.7+/-20.9 nM throughout experimental periods. Mean arterial blood pressure, heart rate and body weight gain remained unaffected by administering ATZ1993. These results demonstrate that ATZ1993 is a novel nonpeptide and nonselective ET(A)/ET(B)-receptor antagonist, and the agent when administered orally inhibits effectively intimal hyperplasia after balloon denudation of the rabbit carotid artery.

Administration, Oral↗

PubMed1999

Susceptibility to hydrogen peroxide and catalase activity of root nodule bacteria.

The root nodule bacteria (free-living cells) tested had higher susceptibility to hydrogen peroxide (H2O2) than the other genera of aerobic or facultative anaerobic bacteria tested. The catalase activities tended to have a positive correlation with H2O2 resistance among all bacteria tested. Addition of a catalase inhibitor such as 3-amino-1, 2, 4-triazole increased the susceptibility to H2O2. These results suggest that the lower catalase activity brings about the higher susceptibility of root nodule bacteria to H2O2. Root nodule bacteria seemed to have two or three catalase isozymes during growth and their catalase activities were higher in log phase than in stationary phase, contrary to other genera of bacteria tested.

Amitrole↗

PubMed1999

Gene expression of vasoactive intestinal contractor/endothelin-2 in ovary, uterus and embryo: comprehensive gene expression profiles of the endothelin ligand-receptor system revealed by semi-quantitative reverse transcription-polymerase chain reaction analysis in adult mouse tissues and during late embryonic development.

Vasoactive intestinal contractor (VIC)/endothelin-2 (ET-2) is a 21 amino acid intestinal peptide characterized as a potent vasoactive and intestinal smooth muscle-contracting compound. To investigate the physiological roles of VIC/ET-2 further, we characterized the specificity of VIC gene expression relative to that of other members of the endothelin (ET) ligand-receptor system in adult mouse tissues and during embryonic development. Gene expression of ET-1, ET-3, ETA and ETB was ubiquitous in almost all tissues we examined while gene expression of VIC was localized to certain tissues. A high level of VIC gene expression was observed in ovary and uterus. The gene expression of VIC, relative to that of glyceraldehyde-3-phosphate dehydrogenase, was approximately 2.0%, 0.4%, and 2.3% in ovary, uterus, and intestine respectively, and was approximately 1.6 and 7. 1 times higher than that of ET-1 in ovary and intestine respectively. Thus, VIC may have some physiological role in adult ovary and uterus as well as intestine. In embryonic development, VIC gene expression sharply increased between 11 and 15 days post coitus and decreased after birth, suggesting an involvement in the later stages of embryonic development.

Animals↗

PubMed1999

A significant morphological transformation is recognized in human esophageal cancer cells with an amplification/overexpression of the cyclin D1 gene.

Amplification and expression status of the CCND1 gene in 12 cell lines derived from esophageal cancer was evaluated and the differences in the cell proliferation and morphology were investigated. Amplification was observed in 6 cell lines, all of which consequently overexpressed the mRNA. Although the amplification of the gene did not contribute to an increase of cell proliferation, an in vitro morphological transformation was observed in the colonies with an amplification of the CCND1 gene. An amplification/overexpression of the CCND1 gene plays an important role in the enhancement of cell transformation in esophageal squamous cell carcinoma cells.

Blotting, Northern↗

PubMed1999

[Long-term efficacy of the Gittes bladder neck suspension with use of ultrasonography for genuine stress urinary incontinence].

Thirty-eight patients with genuine stress incontinence underwent the Gittes procedures of the bladder neck suspension under ultrasonical monitoring. We performed the following two procedures. Original Gittes procedure: the puncture of the needle made twice through the different holes of the rectus fascia for each side and the bilateral helical suture was tied down separately above the rectus fascia. Modified Gittes procedure: the needle was passed through the rectus fascia once for each side and the both end of the helical suture was drawn up to suprapubic area, then the bilateral threads were tied over the rectus fascia. Original Gittes procedure was performed for twenty-nine patients and modified Gittes procedure for nine patients. Tightness of the suspension was decided by monitoring the posterior urethrovesical angle with use of the transrectal ultrasonography during the operation. A long term follow up survey was made up by means of a questionnaire by the phone or the mail. A total of thirty-six patients responded the questionnaire for a 94.7% response rate. The mean follow up was 33.1 months. 83.3% of the patients were cured and 5.6% were significantly improved. None of the patients claimed dysuria. There was no difference between the continent rates of the two procedures. We conclude that the Gittes bladder neck suspension with use of ultrasonography is effective for correction of female stress urinary incontinence.

Aged↗

PubMed1999

[A case of retroperitoneal hemangiopericytoma].

We report a case of a huge retroperitoneal tumor in a 67-year-old woman. When the patient was taken to another hospital by ambulance, she had lost consciousness because of hypertension and hypoglycemia and abdominal CT revealed a huge retroperitoneal tumor with deviation of the right kidney and inferior vena cava. After further examinations including ultrasonography, MRI and angiography in our hospital, the tumor was extirpated. The tumor, 22 x 17 x 10 cm in size and 2,580 g in weight was diagnosed as hemangiopericytoma histologically. She has remained well with no evidence of recurrence for 9 months since the operation.

Aged↗

PubMed1999

[A case of pure leiomyoma of the prostate].

Pure leiomyoma of the prostate is very rare. A 67-year-old man was hospitalized with gross hematuria and urinary retention. Drip infusion pyelography revealed a defect of the urinary bladder. By radiological examinations, submucosal tumor of the bladder neck was diagnosed. Transrectal biopsy suggested a benign prostatic tumor histologically. Open resection of the tumor was performed. Histological findings were pure leiomyoma of the prostate. The postoperative course was good and urinary retention was improved remarkably.

Aged↗

PubMed1999

Natriuretic peptides regulate the expression of tissue factor and PAI-1 in endothelial cells.

In the present study, we demonstrate that brain natriuretic peptide (BNP) and C-type natriuretic peptide (CNP) interact with angiotensin II (Ang II) in regulative blood coagulation and fibrinolysis by suppressing the expressions of both tissue factor (TF) and plasminogen activator inhibitor-1 (PAI-1) induced by Ang II. The expressions of TF and PAI-1 mRNA were analyzed by northern blotting methods, and the activities of TF on the surface of rat aortic endothelial cells (RAECs) and PAI-1 in the culture media were respectively measured by chromogenic assay. Both BNP and CNP suppressed the expressions of TF and PAI-1 mRNA induced by Ang II in a time- and concentration-dependent manner via cGMP cascade, which suppressions were accompanied by respective decrease in activities of TF and PAI-1. However, neither the expression of tissue factor pathway inhibitor (TFPI) nor tissue-type plasminogen activator (TPA) mRNA was affected by the treatment of BNP and CNP.

Angiotensin II↗