Biomedical subjects

H Masuda

Publications and source records attributed to H Masuda.

At least 55 records · Page 3Linked to original sources

PubMed2001

The Japanese Study Group of Insulin Therapy for Childhood and Adolescent Diabetes (JSGIT): initial aims and impact of the family history of type 1 diabetes mellitus in Japanese children.

The Japanese Study Group of Insulin Therapy for Childhood and Adolescent Diabetes (JSGIT) was established in July 1994 with the chief aim to improve the quality of therapy for type 1 diabetes in children, an entity far less common in Japan than in Europe. We proposed four initial research topics: (i) to determine the current status of medical care and glycemic control in Japanese children with type 1 diabetes mellitus; (ii) to standardize the measurement of hemoglobin A1c; (iii) to establish a registry of a large cohort of patients in order to enable prospective studies to improve the quality of therapy for children with type 1 diabetes in Japan; and (iv) to enable participants of the JSGIT to hold a workshop twice annually. We registered a total of 736 patients from 45 hospitals throughout Japan. Intervention via insulin treatment was instituted after 2 yr for those patients whose hemoglobin A1c level was more than 8.1%. The proportion of patients receiving multiple insulin injections increased after intervention; however, average hemoglobin A1c in females remained significantly higher than in males. We identified two forms of diabetes in Japanese children: a rapidly progressive form and a more slowly progressive form. There was a significantly higher prevalence of a family history of diabetes in first-degree relatives in the slowly progressive form. These preliminary findings are the result of the first collaborative study of childhood diabetes in Japan.

Journal Article↗

PubMed2001

Involvement of accumulated endogenous NOS inhibitors and decreased NOS activity in the impaired neurogenic relaxation of the rabbit proximal urethra with ischaemia.

1. We examined the effect of ischaemia on the neurogenic and nitric oxide (NO)-mediated urethral relaxation. 2. Rabbits were divided into control and urethral ischaemia (UI) groups, which was prepared by the partial occlusion of bilateral iliac arteries using blood vessel occluders. 3. Neurogenic and NO-mediated proximal urethral relaxation induced by electrical field stimulation (EFS) was greatly impaired in the UI group, while relaxation by sodium nitroprusside (SNP) as a NO donor showed no difference between the two groups. Pretreatment with L-arginine significantly improved but did not normalize the impaired relaxation in the UI group. Not only basal level, but also stimulated production of cyclic GMP with EFS, were significantly decreased in the UI group. 4. The tissue contents of N(G)-methyl-L-arginine (L-NMA) and asymmetric N(G), N(G)-dimethyl-L-arginine (ADMA) in the proximal urethra were increased following ischaemia. While L-arginine and symmetric N(G), N'(G)-dimethyl-L-arginine (SDMA) contents remained unchanged. Exogenously applied authentic L-NMA and ADMA (1 -- 100 microM) concentration-dependently inhibited the EFS-induced urethral relaxation in the control group. The inhibition with L-NMA and ADMA was undetectable in the presence of 3 mM L-arginine. 5. The Ca(2+)-dependent NOS activity in the urethra from the UI group was significantly lower than that from the control group and was not restored by an addition of 3 mM L-arginine. 6. These results suggest that the impaired neurogenic and NO-mediated urethral relaxation with ischaemia is closely related to the increased accumulation of L-NMA and ADMA and decreased NOS activity, which would result in an accelerated reduction in NO production/release.

Animals↗

PubMed2001

Clinicopathological features of gastric mucosa-associated lymphoid tissue lymphoma: a comparison with diffuse large B-cell lymphoma without a mucosa-associated lymphoid tissue lymphoma component.

BACKGROUND AND AIMS: The aim of this study was to clinicopathologically distinguish the pathogenesis of gastric mucosa-associated lymphoid tissue (MALT) lymphoma and diffuse large B-cell lymphoma without a MALT lymphoma component (DLL). METHODS: We investigated clinicopathological features of these gastric lymphomas including age, sex ratio, tumor location and depth, macroscopic appearance, and infection with Helicobacter pylori of these gastric lymphomas and hepatitis viruses in 24 patients with gastric low-grade MALT lymphoma, 10 patients with high-grade MALT lymphoma, and 19 patients with DLL. The frequency of H. pylori infection in lymphoma patients was compared with that in age- and sex-matched control subjects. RESULTS: There was a predominance of females with MALT lymphoma (male to female ratio, 8/16 for low-grade MALT lymphomas and 1/9 for high-grade MALT lymphomas), and there was a predominance of males with DLL (male to female ratio, 13/6); the ratios differed significantly (P < 0.05). Ninety-two percent of low-grade MALT lymphomas and 80% of high-grade MALT lymphomas were confined to the mucosal and submucosal layers, but lymphoma cells invaded the muscular layer or more deeply in 74% of DLL. Helicobacter pylori infection occurred significantly more often in patients with low-grade MALT lymphoma than in age- and sex-matched controls (96 vs 67%, P < 0.01). Conversely, the frequency of H. pylori infection in DLL patients did not differ from that in controls. CONCLUSIONS: These data suggest that H. pylori infection may be associated with the development of gastric MALT lymphoma, but not DLL, and that MALT lymphoma and DLL may have a different pathogenesis.

Adult↗

PubMed2001

Endometrioid adenocarcinoma arising from adenomyosis: report and immunohistochemical analysis of an unusual case.

A case of endometrioid adenocarcinoma arising from adenomyosis is reported. The patient was a 53-year-old woman who complained of vulvar itching. Smear cytology of the endometrium revealed adenocarcinoma. Magnetic resonance imaging of the pelvis revealed a lesion with a slightly high intensity in the uterine fundus on a T2-weighted image. Semiradical total hysterectomy and bilateral adnexectomy were performed, followed by chemotherapy. Histologically, the lesion in the uterine fundus was composed mostly of adenocarcinoma with stromal invasion. There were many adenomyotic foci in and around the carcinoma, including some showing transition to adenocarcinoma. There was no malignant finding in the normally situated endometrium. The carcinoma invaded in the myometrium, involving the uterine serosa, but no dissemination to the peritoneal cavity was found. The carcinoma was, therefore, considered to be endometrioid adenocarcinoma arising from adenomyosis. Immunohistochemistry showed expression of p53 oncoprotein and Ki-67 antigen in the carcinoma cells. The value of immunohistochemistry in predicting prognosis is discussed.

Adenocarcinoma↗

PubMed2001

Expression of intercellular adhesion molecule 1 (ICAM-1) in Plasmodium falciparum-infected placenta.

We investigated the expression of intercellular adhesion molecule 1 (ICAM-1) in malarial placenta and related histological changes. Thirty-two malarial and 40 control term placentae were collected at Tanga, Tanzania and examined histologically and immunohistochemically. Malaria infected placentae were further divided into acute (15) and chronic (17) cases according to the presence of malarial pigment. The expression of ICAM-1 on monocyte, syncytio- and cytotrophoblasts, endothelial and stromal cells was assessed. Birthweight was lower and leukocyte counts higher in placentae with chronic infection. Many monocytes were present within the intervillous spaces, especially in placentae with chronic infection, and aggregated with parasitized erythrocytes. Some monocytes were adhesive to the surface of fibrinoid deposits. ICAM-1 expression on monocytes of malarial placentae was significantly conspicuous and correlated to the degree of intervillous leukocyte infiltration. Syncytiotrophoblasts often did not show ICAM-1, even though ICAM-1 was expressed by endothelium and weakly by cytotrophoblasts and stromal cells in both infected and control placentae. These results suggest that the expression of ICAM-1 on monocytes contributes to sequestration of infected erythrocytes within the intervillous spaces and their adhesion to fibrin masses and that ICAM-1 is unlikely to be associated with the direct adhesion of infected erythrocytes to the syncytiotrophoblasts.

Birth Weight↗

PubMed2001

Molecular mechanisms of aortic wall remodeling in response to hypertension.

OBJECTIVE: The molecular basis of vascular response to hypertension is largely unknown. Both cellular and extracellular components are critical. In the current study we tested the hypothesis that there is a balance between vascular cell proliferation and cell death during vessel remodeling in response to hypertension. METHODS: A midthoracic aortic coarctation was created in rats to induce an elevation of blood pressure proximal to the coarctation. The time course was 1 and 3 days and 1, 2, and 4 weeks for the study of the proximal aorta. Ribonuclease protection assay and Western blot analysis were used to evaluate gene expression of growth and apoptosis-related cytokines with two sets of multiple probes, rCK-3 and rAPO-1. Cell proliferation was determined with BrdU (5-bromo-2'-deoxyuridine) incorporation. Apoptosis was examined with TUNEL (transferase-mediated dUTP nick end-labeling). Morphometry was performed on histologic sections. RESULTS: Coarctation produced hypertension in the proximal aorta, 118 +/- 9 mm Hg versus 94 +/- 6 mm Hg in controls (P <.002). Both messenger RNA and protein levels of transforming growth factor (TGF)-beta1 and TGF-beta3 were increased (P <.005 vs controls). Messenger RNA and protein of Bcl-xS and Fas ligand, known as proapoptotic factors, were both reduced after coarctation (P <.005 vs controls). There was increased BrdU incorporation at 3 days and 1 and 2 weeks (P <.001 vs controls). There were no remarkable changes in the apoptosis rate until 4 weeks later. CONCLUSION: Cell proliferation was stimulated at 3 days, and apoptosis was halted until 4 weeks. These changes were associated with upregulation of TGF-beta and downregulation of Bcl-xS and Fas ligand gene expression. These findings suggest that a coordinated regulation of cell proliferation and cell death contributes to arterial remodeling in response to acute sustained elevation of blood pressure. Cell proliferation precedes apoptosis by 2 weeks in this procedure.

Animals↗

PubMed2001

Effects of sarpogrelate hydrochloride on adenosine diphosphate- or collagen-induced platelet responses in arteriosclerosis obliterans.

To evaluate the effects of the 5-HT2 receptor antagonist sarpogrelate hydrochloride (sarpogrelate) on platelet responses in arteriosclerosis obliterans (ASO), we examined platelet aggregation and its relationships to platelet-derived growth factor (PDGF), soluble P-selectin (sP-selectin), and transforming growth factor-beta 1 (TGF-beta1). Circulating plasma levels of PDGF and sP-selectin in 13 patients with ASO after 1 week of medication with sarpogrelate were significantly lower than those before medication. In contrast, circulating plasma levels of TGF-beta1 after medication were significantly higher than those before medication. When platelet-rich plasma obtained from ASO patients after medication was stimulated with adenosine diphosphate (ADP) or collagen, platelet aggregation was suppressed compared with rates before medication. Significant decreases in levels of PDGF, sP-selectin and TGF-beta1 released from platelets in response to 5 micromol/l ADP and 1 microg/ml collagen after taking of sarpogrelate were found. There were close correlations between platelet aggregation and respective molecules released from platelets. In conclusion, since platelet activation is involved in pathogenesis of thrombotic disease, sarpogrelate may suppress the development of obstructive arteriosclerosis. PDGF and TGF-beta1, as well as sP-selectin, appear to be useful markers for clinical evaluation of anti-platelet drugs.

Adenosine Diphosphate↗

PubMed2001

Upregulatory expression of furin and transforming growth factor-beta by fluid shear stress in vascular endothelial cells.

Furin, a yeast Kex2-family endoprotease, converts many vasoregulatory propeptides, including pro-transforming growth factor (TGF)-beta to their mature forms. We examined whether furin expression is regulated by shear stress in vivo and in vitro. When an arteriovenous shunt was placed between the carotid artery and external jugular vein in rabbits, furin and TGF-beta were highly expressed in shear stress-loaded endothelial cells. Exposure of bovine aortic endothelial cells in culture to shear stress induced furin and TGF-beta expression in a similar manner. Molecular analysis of furin expression in bovine aortic endothelial cells revealed that shear stress increases the furin gene expression at transcriptional levels. Furthermore, TGF-beta itself increased the furin mRNA levels. Shear-mediated furin expression was partly mediated by TGF-beta because shear-induced furin mRNA levels were considerably decreased by overexpression of the truncated form of the TGF-beta type II receptor. Likewise, blockade of furin activity by a furin inhibitor significantly decreased the endothelial production of mature TGF-beta. Taken together, the results indicate that furin expression is induced and maintained by a coordination of shear stress and TGF-beta. Increased furin expression may facilitate the formation of mature TGF-beta, resulting in the enhanced effects of TGF-beta on endothelial cells and vascular smooth muscle cells in the vasculature.

Animals↗

PubMed2001

Adrenomedullin inhibits angiotensin II-induced expression of tissue factor and plasminogen activator inhibitor-1 in cultured rat aortic endothelial cells.

Adrenomedullin (AM) is a potent vasodilating peptide having a variety of pharmacological properties mainly in respect to vascular pathophysiology. We have previously demonstrated that angiotensin II (Ang II) or natriuretic peptides have influence on the expression of tissue factor (TF) and plasminogen activator inhibitor-1 (PAI-1) in vascular endothelial cells. The aim of this study was to elucidate the effects of AM on TF and PAI-1 mRNA and protein expression in endothelial cells. As a result, AM inhibited Ang II-induced TF and PAI-1 mRNA expression in a dose- and time-dependent manner. Because the expression of TF and PAI-1 mRNA induced by Ang II was attenuated by the increase of intracellular concentrations of cAMP by forskolin and 8-bromo-cAMP and because AM increased the intracellular level of cAMP in rat aortic endothelial cells, it was indicated that the inhibitory effect of AM on the expressions of TF and PAI-1 was mainly mediated by the cAMP-dependent signal transduction. Furthermore, the inhibitory effect of AM on TF and PAI-1 expression was partly attenuated by an NO synthase inhibitor, N(G)-nitro-L-arginine methyl ester. In conclusion, AM is shown to contribute to the regulation of blood coagulation and fibrinolysis by vascular endothelial cells mainly via the cAMP pathway.

8-Bromo Cyclic Adenosine Monophosphate↗

PubMed2001

Blood flow decrease induces apoptosis of endothelial cells in previously dilated arteries resulting from chronic high blood flow.

We investigated apoptosis of endothelial cells during the arterial narrowing process in response to reduction in flow. The decrease in flow was created in the carotid artery by closure of an arteriovenous fistula (AVF), which had been established for 28 days in rabbits. The endothelial cell apoptosis in the carotid artery was studied at 1, 3, 7, and 21 days of flow reduction after closure of the AVF by use of terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling (TUNEL) with laser scanning confocal microscopy and transmission and scanning electron microscopy. After AVF closure, arterial lumen diameter was reduced by 36%, and compared with endothelial cells before the closure, the number of endothelial cells was decreased by 45% at 21 days. Endothelial cell apoptosis was observed at 1 day, peaked at 3 days (381.3+/-87.1 cells per square millimeter), and decreased at 7 days. These cells had irregular protrusions under scanning electron microscopy and were characterized by fragmented nuclei under transmission electron microscopy. Apoptotic cells were mainly beneath the endothelium and were occasionally within smooth muscle cells and endothelial cells. The results suggest that apoptosis of endothelial cells may play a role in the arterial remodeling in response to a reduction in flow.

Animals↗

PubMed2001

HMG-CoA reductase inhibitor mobilizes bone marrow--derived endothelial progenitor cells.

Endothelial progenitor cells (EPCs) have been isolated from circulating mononuclear cells in peripheral blood and shown to incorporate into foci of neovascularization, consistent with postnatal vasculogenesis. These circulating EPCs are derived from bone marrow and are mobilized endogenously in response to tissue ischemia or exogenously by cytokine stimulation. We show here, using a chemotaxis assay of bone marrow mononuclear cells in vitro and EPC culture assay of peripheral blood from simvastatin-treated animals in vivo, that the HMG-CoA reductase inhibitor, simvastatin, augments the circulating population of EPCs. Direct evidence that this increased pool of circulating EPCs originates from bone marrow and may enhance neovascularization was demonstrated in simvastatin-treated mice transplanted with bone marrow from transgenic donors expressing beta-galactosidase transcriptionally regulated by the endothelial cell-specific Tie-2 promoter. The role of Akt signaling in mediating effects of statin on EPCs is suggested by the observation that simvastatin rapidly activates Akt protein kinase in EPCs, enhancing proliferative and migratory activities and cell survival. Furthermore, dominant negative Akt overexpression leads to functional blocking of EPC bioactivity. These findings establish that augmented mobilization of bone marrow-derived EPCs through stimulation of the Akt signaling pathway constitutes a novel function for HMG-CoA reductase inhibitors.

Animals↗

PubMed2001

Effects of peppermint (Mentha piperita L.) extracts on experimental allergic rhinitis in rats.

The present study was carried out to clarify the effects of extracts of the leaves of Mentha piperita L. on experimental allergic rhinitis. The 50% EtOH extract of peppermint inhibited histamine release from rat peritoneal mast cells induced by compound 48/80. The effect was dose-dependent and significant inhibition was observed at a concentration of 3 microg/ml. In addition, the 50% EtOH eluate separated from the 50% EtOH extract of peppermint by column chromatography (DIAION HP-20) was also effective in inhibiting histamine release at a concentration of 1 microg/ml. Nasal symptoms, sneezing and nasal rubbing induced by antigen challenge in actively sensitized rats were inhibited by oral administration of the 50% EtOH eluate. Significant inhibition of sneezing and nasal rubbing was observed at doses of 300 and 1000 mg/kg, p.o., respectively. Furthermore, the 50% EtOH eluate inhibited dye leakage into the nasal cavity of rats induced by antigen in a dose-dependent manner. These results suggested that extracts of Mentha piperita L. may be clinically effective in alleviating the nasal symptoms of allergic rhinitis.

Animals↗

PubMed2001

Usefulness of the combination of pre- and intraoperative selective intraarterial calcium injection to detect residual insulinomas.

In a 35-year-old woman diagnosed with insulinoma selective intraarterial calcium injection was positive for proximal gastroduodenal artery and inferior pancreaticoduodenal artery involvement preoperatively. Although non-invasive imaging studies were negative, a mass was detected at the pancreatic uncus by intraoperative ultrasonography. Gastroduodenal artery calcium injection was performed after enucleation of the tumor. Following calcium injection, the insulin level was inappropriately increased and further pancreaticoduodenectomy was performed. After excision, another tumor was detected at the head of the pancreas by histopathological examination. As shown, selective intraarterial calcium injection is useful to localize tumors preoperatively and intraoperatively.

Adult↗

PubMed2001

Helicobacter pylori eradication therapy for high-grade mucosa-associated lymphoid tissue lymphomas of the stomach with analysis of p53 and K-ras alteration and microsatellite instability.

Recent studies have shown that 70-80% of low-grade mucosa-associated lymphoid tissue (MALT) lymphomas regress in response to eradication of Helicobacter pylori (H. pylori). However, there are no reports on whether gastric high-grade MALT lymphomas regress after H. pylori eradication. We performed H. pylori eradication therapy in 4 patients with stage I, high-grade MALT lymphoma after obtaining their informed consent. H. pylori infection was observed in all 4 patients. The patients were treated with proton-pump inhibitor-based eradication therapy for 1 or 2 weeks, and then underwent endoscopic examination and biopsy sampling. H. pylori eradication was achieved in all 4 patients. Six months after eradication treatment, 2 patients showed complete regression of the lymphoma and 2 patients showed no change. The 2 patients with non-responding lymphoma were then treated with an additional chemotherapy (CHOP regimen), whereupon the tumors completely regressed. These patients, followed-up at least 18 months after eradication treatment, showed no recurrence. We also examined genetic alteration of the p53 and K-ras genes and microsatellite instability in these high-grade MALT lymphomas. One patient with a tumor that showed no change after H. pylori eradication, had a loss of heterozygosity of the p53 gene. No other genetic alterations were detected among the patients. Our results indicate that the eradication of H. pylori may be effective not only for patients with low-grade MALT lymphoma but also for patients with high-grade MALT lymphoma. The treatment may be efficacious as a first-line therapy for patients with high-grade MALT lymphoma. However, our sample size was limited and further studies are needed to clarify the issue.

Aged↗

PubMed2001

Role of a central muscarinic cholinergic pathway for relaxation of the proximal urethra during the voiding phase in rats.

PURPOSE: We examined the role of a central muscarinic cholinergic pathway in proximal urethral function during the voiding phase. MATERIALS AND METHODS: During isovolumetric bladder contraction we independently recorded proximal urethral pressure, external urethral sphincter activity, and hypogastric and pelvic nerve discharge in urethane anesthetized rats. We administered intravenous, intrathecal or intracerebral ventricular atropine sulfate and atropine methyl nitrate. Atropine sulfate crosses the blood-brain barrier, while atropine methyl nitrate does not. RESULTS: Filling the bladder with 0.5 ml saline induced rhythmic urethral relaxation accompanied by efferent burst discharges from the pelvic nerve. When administered intravenously, only atropine sulfate caused the dose dependent inhibition of urethral relaxation and efferent pelvic nerve discharge. Neither atropine sulfate nor atropine methyl nitrate affected the maximum firing rate of the external urethral sphincter or hypogastric efferent discharge. Intrathecal and intracerebral ventricular atropine sulfate and atropine methyl nitrate similarly inhibited urethral relaxation. CONCLUSIONS: These results suggest that excitation of the central muscarinic cholinergic pathway at a supraspinal or spinal site promotes proximal urethral relaxation during the voiding phase through the activation of efferent pathways in the pelvic nerves.

Animals↗

PubMed2001

[Experience of four cases of postoperative pulmonary embolism requiring surgical treatment].

Four patients underwent a pulmonary embolectomy using cardiopulmonary bypass for acute pulmonary embolism which had occurred after various operations. In two cases, dehydration due to either diabetes insipidus or ileus had existed. In two cases, pulmonary embolism suddenly occurred in our hospital. In the remainder, the disease occurred in the previous hospitals and its diagnosis was established on the 6th and 7th postoperative days, respectively. In massive pulmonary embolism, echocardiography and/or enhanced chest CT are useful for prompt and noninvasive diagnosis. Thrombolytic therapy was performed in only one case before surgical embolectomy, which was not effective. Three patients were discharged without any postoperative complications, but one requiring preoperative external cardiac massage died of multiple organ failure 9 days after operation. Acute pulmonary embolism is one of the fatal postoperative complications. Recognition of this entity, and prompt diagnosis and treatment are essential for managing the fatal disease. Even in the early postoperative period, embolectomy using cardiopulmonary bypass is a safe and effective treatment.

Acute Disease↗

PubMed2001

Double left renal vein associated with abdominal aortic aneurysm.

Double left renal vein is a rare venous anomaly. We operated on 72-year-old man of abdominal aortic aneurysm (AAA) with double left renal vein. Massive hemorrhage was encountered during encircling the tape around the abdominal aorta. One vein passing posterior to the aorta was injured. Further dissection revealed the presence of double left renal vein forming a ring around the aorta. The patient underwent an abdominal aortic replacement following prompt repair of the injured vein. He had an uneventful postoperative course without renal complication. We missed that preoperative computed tomographic (CT) scan had demonstrated double left renal vein. Preoperative contrast-enhanced CT scan is useful and essential not only for evaluation of AAA, but also for establishing the presence of venous anomalies. Venous anomalies should be taken into consideration on the AAA operation.

Aged↗

PubMed2001

Expression of L-type amino acid transporter 1 in a rat model of liver metastasis: positive correlation with tumor size.

The purpose of this study was to examine whether L-type amino acid transporter 1 (LAT1), one of the amino acid transporters, is related closely to tumor size in liver metastasis. Rat colon cancer cells (RCN-9) were injected into the capsule of the spleen of 12 male rats (inbred F344/DuCrj). Conversely, four rats received only phosphate-buffered saline (control group 1), and four rats underwent only laparotomy (control group 2). In each rat, the metastatic tumors, areas surrounding tumor nodules, or the livers of the control groups were immunostained with the antibodies to LAT1 C peptide antigen. In control groups 1 and 2, normal hepatocytes did not indicate a staining of LAT1. A total of 90 metastatic nodules were found in 12 livers with metastasis. Of the 90 metastatic nodules, 43 nodules indicated a positive staining of LAT1. Conversely, the remaining 47 metastatic nodules had a negative staining of LAT1. The average size in metastatic nodules in the group with positive staining of LAT1 was 1.6 +/- 0.4 mm2, which was significantly higher than that of the group with negative staining of LAT1 (0.6 +/- 0.2 mm2; P = .0007). The ratio of the average area of the metastatic nodule against the average largest section of the left lobe of the lateral segment (RML, %) was measured. The RML in the group with positive staining of LAT1 was 1.2 +/- 0.3%, whereas the RML in the group with negative staining of LAT1 was 0.4 +/- 0.1%. A significant difference was noted between the two groups (P = .0004). We concluded that LAT1 plays an important role in tumor cell growth of liver metastatic tumors.

Animals↗