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Biomedical subjects

K Murakami

Publications and source records attributed to K Murakami.

At least 91 records · Page 5Linked to original sources
PubMed2001

Reaction kinetics and modeling of the enzyme-catalyzed production of lactosucrose using beta-fructofuranosidase from Arthrobacter sp. K-1.

Lactosucrose synthesis from sucrose and lactose was carried out by using beta-fructofuranosidase from Arthrobacter sp. K-1. The transfructosylation mechanism was found to be of an ordered bi-bi type in which sucrose was bound first to the enzyme and lactosucrose was released last. Hydrolysis side-reaction experiments indicated that the reactions were uncompetitively inhibited by glucose and lactose, while no inhibition by fructose was apparent. The overall reaction rates were formulated. The reaction rate constants, equilibrium constant, and dissociation and Michaelis constants were determined at 35 degrees C and 50 degrees C by fitting the experimental concentration changes with the calculated values by a nonlinear least-square method. The average relative derivation for the concentrations was 9.67%. The kinetic parameters were also calculated for 43 degrees C and 60 degrees C by assuming the Arrhenius law, and the course of reaction was predicted. The obtained reaction rate equations well represented the concentration changes during the experiment at all temperatures.

Algorithms↗
PubMed2001

Acute effect of human cardiotrophin-1 on hemodynamic parameters in spontaneously hypertensive rats and Wistar Kyoto rats.

There is considerable evidence to indicate that humoral factors play an important role in the development of left ventricular hypertrophy. Cardiotrophin-1 (CT-1) is a cytokine that has been shown to induce cardiac hypertrophy in a dose-dependent manner. The aim of the present study was to investigate the acute effect of CT-1 on hemodynamic parameters in spontaneously hypertensive rats (SHR) and Wistar Kyoto rats (WKY) and to study the relationship between the plasma concentration of CT-1 and its hemodynamic effect. Ten-week-old SHR and age-matched WKY were used. Blood pressure (BP), heart rate (HR) and plasma concentration of CT-1 were measured both before and for 60 min after intravenous bolus injection of human CT-1 (10 microg/kg). CT-1 injection significantly decreased BP and significantly increased HR in SHR and WKY. There were significant differences in BP and HR between the two groups at all time points after injection. The lowest BP, highest HR and maximal plasma concentrations of CT-1 were observed in both groups within 10 min after injection. However, after converting the values into the percentage change from their respective baselines, there were no significant differences between the two groups in BP or HR at any time point. There was also no significant difference between the two groups at any time point in the plasma concentration of CT-1. This study indicates that CT-1 decreases BP and increases HR in both SHR and WKY. The most obvious change occurred within 10 min after injection. However, there was no significant difference in the hypotensive effect of CT-1 on 10-week-old SHR and WKY.

Animals↗
PubMed2001

p53, but not c-Ki-ras, mutation and down-regulation of p21WAF1/CIP1 and cyclin D1 are associated with malignant transformation in gastric hyperplastic polyps.

To investigate tumorigenesis in the gastric hyperplastic polyp (HP), we evaluated 19 HPs with and 50 HPs without dysplasia (including carcinoma in situ), as compared with normal mucosa and fundic gland polyps. Helicobacter pylori density was highest in HPs without dysplasia. Apoptotic activity and Ki-67 and p53 expression also were higher in dysplasia in HPs than in normal mucosa, fundic gland polyps, or HPs themselves. The p21WAF1/CIP1 and cyclin D1 levels, in contrast, were highest in HPs. In HPs without dysplasia, size was correlated positively with the degree of stromal inflammation and with p53 and cyclin D1 expression. p53 and c-Ki-ras mutations were detected in 41% (8/19) and 5% (1/19) of dysplasia (including carcinoma in situ) in HPs. Our results demonstrate that the HP enlarges with enhanced cell turnover and overexpression of p53, p21WAF1/CIP1, and cyclin D1, associated with H pylori-related inflammation, and that p53 but not c-Ki-ras mutations may have an important role in dysplastic change in HPs.

Adult↗
PubMed2001

Affective states associated with bingeing and purging behaviours in Japanese patients with bulimia nervosa.

This study investigated the relationship between binge-purge episodes and the affective state by analysing the changes in affective states during the binge-purge cycle. Thirty-seven Japanese patients with bulimia nervosa were surveyed for 22 types of affective states. Some negative affects were alleviated by bingeing or purging, while others were exacerbated by these behaviours. These findings suggest that one has to differentiate the temporal situations in the binge-purge cycle in considering the relationship between the affective states and binge-purge behaviours. The escape hypothesis and hopelessness hypothesis proposed by Beebe (1994) suggest some possible mechanisms. Binge and purge behaviours should be examined separately as defence functions to regulate negative moods and as acting out in response to intense negative affects.

Adult↗
PubMed2001

Vestibuloplasty after secondary alveolar bone grafting.

OBJECTIVE: This paper introduces a surgical technique for vestibuloplasty after secondary alveolar bone grafting of patients with cleft lip and palate (CLP). This paper also reports on the patients who underwent this modified vestibuloplasty. SURGICAL PROCEDURE: The vestibuloplasty technique described in this paper consists of: (1) reduction of submucosal scar tissue of the upper lip, (2) V-Y plasty of the superficial mucosa, (3) placement of horizontal mattress sutures between nostril floor skin and freed marginal mucosa, (4) application of artificial skin to cover the exposed periosteal surface, and (5) use of a removable retention splint. CONCLUSION: This surgical procedure appears to be very useful for patients with CLP. The technique enables the surgeon to obtain an adequate sulcus depth around the graft area. In addition, this technique releases the mucosal scar contraction and improves the shape and mobility of the upper lip.

Adolescent↗
PubMed2001

Pulmonary lymphoma of large B-cell type mimicking Wegener's granulomatosis.

A 27-year-old man with a primary pulmonary lymphoma of large B-cell type is described. Symptoms involved both the upper and lower respiratory tract. A chest roentgenogram showed a dense mass with cavitation. Transbronchial biopsy specimens revealed no atypical cells, rather they demonstrated granulomatous infiltration and vasculitis consistent with but not conclusively diagnostic of Wegener's granulomatosis. The pulmonary mass became smaller after sulfamethoxazole-trimethoprim therapy. These features suggested Wegener's granulomatosis. However, an open biopsy specimen was diagnostic for diffuse lymphoma of large B-cell type. High-grade pulmonary lymphoma should be considered in the differential diagnosis of patients with clinical and pathologic features suggesting Wegener's granulomatosis.

Adult↗
PubMed2001

Cavernous angioma of the corpus callosum mimicking an astrocytic tumor--case report.

A 49-year-old female presented with a mass at the genu of corpus callosum manifesting as vertiginous sensation persisting for a couple of months. The preoperative diagnosis based on neuroimaging was astrocytic tumor, probably an oligodendroglioma. The mass was totally excised through a left interhemispheric approach without postoperative neurological deficits. Histological examination of the mass revealed only vascular components with tiny hemorrhage, compatible with cavernous angioma. Cavernous angioma at the genu of corpus callosum is very rare, and definitive diagnosis can be achieved only through surgery. Surgical intervention should be considered before starting radiotherapy without histological confirmation.

Corpus Callosum↗
PubMed2001

Xanthurenic acid inhibits metal ion-induced lipid peroxidation and protects NADP-isocitrate dehydrogenase from oxidative inactivation.

Vitamin B6 deficiency increases the lipid peroxidation and the synthesis of xanthurenic acid from tryptophan. Antioxidant properties of xanthurenic acid were examined in relation to the coordination of transition metals. Xanthurenic acid inhibited the formation of thiobarbituric acid-reactive substances as a marker of iron-mediated lipid peroxidation and copper-dependent oxidation of low density lipoprotein. NADP-isocitrate dehydrogenase (EC 1.1.1.42), a principal NADPH-generating enzyme for the antioxidant defense system, was inactivated by reduced iron and copper, and xanthurenic acid protected the enzyme from the Fe2+-mediated inactivation. Xanthurenic acid may participate in the enhanced regeneration of reduced glutathione by stimulating the NADPH supply. Xanthurenic acid further enhanced the autooxidation of Fe2+ ion. Other tryptophan metabolites such as kynurenic acid and various quinoline compounds did not inhibit the lipid peroxidation and the inactivation of NADP-isocitrate dehydrogenase, and they showed little or no effect on the Fe2+ autooxidation. The antioxidant properties of xanthurenic acid are related to the metal-chelating activity and probably to the enhanced oxidation of reduced transition metals as a prooxidant, and this action may be due to the electron deficient nature of this compound.

Antioxidants↗
PubMed2001

[Selection of antibiotics and planning of eradication for H. pylori infection].

There is general agreement that H. pylori should be eradicated in patients with peptic ulcers. But the optimal therapeutical regimen to be used still remains a matter for many investigations. An increase in the prevalence of antibiotic-resistant H. pylori strains has been reported recently. The recommended drugs for the eradication in Japan are clarithromycin (CAM) and amoxicillin (AMPC) because metronidazole (MNZ) is anti-parasites drug in Japan. A total of 392 H. pylori strains in the last twelve years were tested for sensitivity to CAM, MNZ, and AMPC. The Primary resistance of H. pylori to CAM, MNZ, and AMPC were found in 10.2%, 26.5%, and 0.3% strains, respectively. The resistant strains to CAM were gradually increasing in the last few years. The eradication therapies which do not increase antibiotics resistant strains after eradication failure were reported. The recommendation for eradication in patients with peptic ulcer disease includes those with bleeding ulcers. The pretreatment with proton pump inhibitors (PPI) does not influence the success of PPI-based triple therapy in eradicating H. pylori.

2-Pyridinylmethylsulfinylbenzimidazoles↗
PubMed2001

[Occurrence of upper gastrointestinal tract disease after Helicobacter pylori eradication].

Helicobacter pylori (H. pylori) infection is recognized to be a pathogen of various gastro-duodenal disease. Eradication therapy of H. pylori reduces the recurrence of gastro-duodenal ulcer, improves gastritis histologicaly, and is suggested to act an certain role in protection against gastric carcinogenesis. Although, several studies show uncomfortable results arise after H. pylori infection was cured. These studies suggest that gastro-esophageal reflux disease (GERD) and gastro-doudenal erosion may increase after successful eradication of H. pylori. Recently, adenocarcinoma of the gastric cardia and esophagus increase in incidence. Reflux esophagitis and Barrett's esophagus are recognized as precancerous lesion of esophageal adenocarcinoma. It is uncertain the association of newly occurrence of GERD after H. pylori eradication and increase of esophageal adenocarcinoma. Although GERD may lead to adenocarcinoma, long term observations is necessary after H. pylori eradication.

Adenocarcinoma↗
PubMed2001

Accumulation of extracellular matrix in the liver induces high metastatic potential of hepatocellular carcinoma to the lung.

The liver undergoes pathogenic changes such as hepatitis, fibrosis and cirrhosis under continuous stimulation by hepatitis virus or alcohol intake, leading to the development of hepatocellular carcinoma. The metastatic potential of HCC can be positively or negatively regulated by pathogenic alterations of liver. We investigated whether the metastatic abilities of HCC after orthotopic implantation can be influenced in the fibrotic liver by continuous injection of carbon-tetrachloride (CCl4) for seven weeks. The incidence of lung metastasis after orthotopic implantation of murine HCC (CBO140C12) fragments into CCl4-treated livers was higher than into normal livers. The amount of mRNA for MMP-2 increased in the CCl4-treated livers as compared with normal livers, and CBO140C12 cells constitutively expressed mRNA for MT1-MMP in early amplification cycles by RT-PCR. In addition, we found that the culture of CBO140C12 cells on the substrates pre-coated with ECM components increased the expression of MMP-2 mRNA. Thus, enhanced incidence of lung metastasis in the fibrotic liver might be partly due to: i) over-expression of MMP-2 in the fibrotic liver in cooperation with MT1-MMP on the CBO140C12 cell surface, ii) over-expression of MMP-2 in CBO140C12 cells, possibly mediated by the interaction of tumor cells (surface integrins) with accumulated ECM in the fibrotic liver. This is the first report showing that increase of MMP-2 in the fibrotic liver can influence the metastatic potential of HCC cells.

Animals↗
PubMed2001

[Multislice CT of the thorax: effects of contrast material pushed with saline solution using a dual power injector on contrast material dose and perivenous artifacts].

A new method of power injection of contrast material flushed with saline solution for thoracic multislice CT using a dual power injector was evaluated in 105 patients. The patients were categorized into 3 groups of 35 patients each, according to the protocol of contrast material administration: (1) 100 mL of non-ionic contrast material(300 mgI/mL), (2) 75 mL of the same contrast material, and (3) 75 mL of the same contrast material flushed with 30 mL of saline solution. Scanning was performed in a caudal-to-cranial direction. Mean attenuation for the three protocols was measured in the superior vena cava, pulmonary trunk, ascending aorta, and descending aorta. Vascular opacification and perivenous artifacts were graded using four-point scoring by a consensus panel of three blinded radiologists. Intravenous injection of 75 mL of contrast material flushed with saline solution provided significantly better vascular opacification in the superior vena cava(p < 0.001) and pulmonary trunk(p < 0.02) than that provided by a 75 mL or 100 mL injection of contrast material alone. A similar degree of enhancement was observed in the ascending and descending aorta. Further, perivenous artifacts in the subclavian vein were significantly reduced (p < 0.05).

Adult↗
PubMed2001

[Orchiectomy for tuberculous epididymitis: a report of two cases with intractable to antituberculosis treatment].

This paper describes two cases with tuberculous epididymitis. The first case was a 69-year-old man who was admitted to our hospital because of ulceration or right scrotum. Physical examination revealed a hard, rounded, a little bigger than egg-sized mass in the right scrotum. The second case was a 40-year-old man who was admitted to our hospital because of cough, fever and body weight loss. He was treated for pulmonary tuberculosis with isoniazid, rifampicin, streptomycin and pyrazinamide. Six months after admission, he complained of a painless swelling of the right scrotum. Physical examination revealed a hard, rounded, more than egg-sized mass in the right scrotum. Right orchiectomy was performed in these two cases, and they were cured.

Adult↗
PubMed2001

[Quantitative determination of lipoprotein by agarose gel electrophoresis and enzymatic staining of cholesterol and triglyceride: effects of age and gender].

290 normal duplicate samples (152 males and 138 females), were subjected to lipoprotein analysis by agarose gel electrophoresis to yield HDL, VLDL and LDL fractions which were respectively stained with Cholesterol and Triglyceride reagents. HDL-Cholesterol were significantly higher in female than male, and VLDL-TG were significantly higher in male than female. Assay C.V.'s varied from 0.96 to 5.75 for cholesterol fractions and 2.00 to 4.34 for triglyceride fractions. Comparison of electrophoretic HDL-Cholesterol and LDL-Cholesterol concentrations with the results of a direct method (HDL-EX and LDL-EX, Denka Seiken) gave correlation coefficients of 0.967 and 0.952 respectively. This method is simple, rapid and can provide the simultaneous assessment of the cholesterol and triglyceride component in each Lipoprotein fraction. Additionally, the method is useful for evaluating lipoprotein assays.

Adult↗
PubMed2000

Basophil responses to chemokines are regulated by both sequential and cooperative receptor signaling.

To investigate human basophil responses to chemokines, we have developed a sensitive assay that uses flow cytometry to measure leukocyte shape change as a marker of cell responsiveness. PBMC were isolated from the blood of volunteers. Basophils were identified as a single population of cells that stained positive for IL-3Ralpha (CDw123) and negative for HLA-DR, and their increase in forward scatter (as a result of cell shape change) in response to chemokines was measured. Shape change responses of basophils to chemokines were highly reproducible, with a rank order of potency: monocyte chemoattractant protein (MCP) 4 (peak at <1 nM) >/= eotaxin-2 = eotaxin-3 >/= eotaxin > MCP-1 = MCP-3 > macrophage-inflammatory protein-1alpha > RANTES = MCP-2 = IL-8. The CCR4-selective ligand macrophage-derived chemokine did not elicit a response at concentrations up to 10 nM. Blocking mAbs to CCR2 and CCR3 demonstrated that responses to higher concentrations (>10 nM) of MCP-1 were mediated by CCR3 rather than CCR2, whereas MCP-4 exhibited a biphasic response consistent with sequential activation of CCR3 at lower concentrations and CCR2 at 10 nM MCP-4 and above. In contrast, responses to MCP-3 were blocked only in the presence of both mAbs, but not after pretreatment with either anti-CCR2 or anti-CCR3 mAb alone. These patterns of receptor usage were different from those seen for eosinophils and monocytes. We suggest that cooperation between CCRs might be a mechanism for preferential recruitment of basophils, as occurs in tissue hypersensitivity responses in vivo.

Basophils↗
PubMed2000

Expression of membrane-type 1 matrix metalloproteinase (MT1-MMP) on prostate cancer cell lines.

Membrane-type metalloproteinase-1 (MT1-MMP) is a transmembrane metalloproteinase, which activates proMMP-2 and expressed on the cell surface in many invasive cancer cells. We investigated the expression of MT1-MMP in prostate cancer cell lines. MT1-MMP protein and mRNA were expressed in PC-3, DU-145 and TSU-pr1 cells (androgen-independent prostate cancer cell lines), but in LNCaP cells (androgen-dependent prostate cancer cell line). MT1-MMP protein was negative and mRNA was low to detect by RT-PCR. Cell lysate of PC-3 cleaved proMMP-2 to the active form. In addition, both hepatocyte growth factor (HGF) and gastrin-releasing peptide (GRP) increased Matrigel invasion and induced the expression of MT1-MMP protein in DU-145 prostate cancer cells. These results suggest that MT1-MMP is indeed the tumor-specific activator of proMMP-2 in androgen-independent prostate cancer cells and plays an important role in the invasive properties of prostate cancer cells.

Catalysis↗