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Biomedical subjects

M Miyamoto

Publications and source records attributed to M Miyamoto.

At least 19 recordsLinked to original sources
PubMed1995

Induction of Fas-mediated apoptosis in p53-transfected human colon carcinoma cells.

To investigate the biological function of p53 in colon carcinoma cells, a wild-type p53 expression plasmid under the control of the human cytomegalovirus promoter was stably transfected into the human colon adenocarcinoma cell line WiDr, which carries a mutation of the p53 gene at codon 273. Exogenous wild-type p53 transcripts were detected at various expression levels in 8 of 117 G418-resistant clones. The growth rates of the wild-type p53+ clones in culture did not change significantly. The efficiency of colony formation in soft agar, however, was completely suppressed in two wild-type p53+ clones. This is the first to demonstrate the feasibility of stable transfection of the wild-type p53 gene under the control of non-inducible promoter in human colon cancer cells. The major alteration found was that wild-type p53+ cells which were incubated with anti-Fas IgM showed marked cytolysis with preferential over-expression of wild-type p53 accompanied by overexpression of a cyclin-dependent kinase inhibitor, WAF1, whereas the endogenous mutant p53 retained its expression level. The findings suggest that a Fas-initiated pathway is incidentally linked to a p53-dependent apoptotic pathway through the reconstituted wild-type p53 gene in WiDr cells. This model should help elucidating the additional role of the p53 tumor suppressor gene and the mechanism of apoptosis in colon carcinoma cells.

Adenocarcinoma↗
PubMed1995

Bacterial steroid monooxygenase catalyzing the Baeyer-Villiger oxidation of C21-ketosteroids from Rhodococcus rhodochrous: the isolation and characterization.

Steroid monooxygenase from Rhodococcus rhodochrous, isolated in homogeneity with a high yield, catalyzes Baeyer-Villiger oxidation of progesterone to produce testosterone acetate with the stoichiometric consumptions of NADPH and molecular oxygen. It is a flavoenzyme with the molecular size of 60 kDa in the monomeric form and the isoelectric point of 4.9. The absorption spectrum has the maxima at 278, 376, and 439 nm and the shoulders at 360 and 465 nm, indicating a strong hypsochromic shift (blue-shift) of the absorption peak in the visible wavelength region. The prosthetic group of the enzyme was identified to be FAD, and the Kd value was estimated to be 0.95 microM. The enzyme catalyzed only the oxidative esterification of progesterone, 11 alpha- and 11 beta-hydroxyprogesterone and not the oxidative lactonization of androstenedione. Km for progesterone was 100 microM, for NADPH was 3.3 microM, and the turnover number was 185 min-1. Kd values for progesterone, 11 alpha-hydroxyprogesterone, deoxycorticosterone, and androstenedione were 110, 130, 2000, and 450 microM, respectively. The optimum pH of the reaction was about 8.5. The reaction was inhibited competitively by 17 alpha-hydroxyprogesterone and androstenedione. Amino terminal sequences of the enzymes from the bacterium and also from fungus, Cylindrocarpon radiocicola were considerably different, and the potential flavin-binding site could be detected on the amino-terminal region of the fungus enzyme but not on that of the bacterial enzyme. Western blotting analyses of the two steroid monooxygenases resulted that mouse antiserum raised for each enzyme reacted only with the antigenic enzyme protein but did not show the cross-reactions. It is clarified that bacterial steroid monooxygenase is distinctly different from the fungal enzyme in the molecular and enzymic properties.

Amino Acid Sequence↗
PubMed1995

Fetal pancreas transplantation in miniature swine. V. The functional and immunodulatory effects of ultraviolet light on fetal pig islets.

We have used the pig as a large animal model for studies of fetal pancreas transplantation. Fetal pig pancreas (FPP) has also been proposed as a potential source of endocrine cells for the treatment of diabetes mellitus. Among the approaches to prevent rejection, the irradiation of donor islets with ultraviolet B light has been used for its immunomodulating properties. Our goal was to study in vitro the effects of UV-B irradiation of FPP on the function and immunogenicity of the tissue. FPP were collagenase-digested and cultured for 1-29 days prior to UV-B irradiation. Static incubation tests were used to measure glucose-theophylline stimulated insulin release. Data obtained at 300 J/m2 revealed no impairment of insulin release (78% to 129% of controls, P = ns). At 500 J/m2, a significant reduction of glucose-theophylline stimulated insulin release was observed with 50-60-day-old FPP (35% to 66% of controls, P < 0.05), but not with 80-day-old FPP (93% of controls, P = ns). At both doses, prolonged observation in culture did not show any alteration of the growth and proliferation of islet cell clusters. UV-irradiated (300 J/m2) adult and fetal pig islet allografts released C-peptide and survived > 200 days. The immunogenicity of irradiated tissues was determined in vitro with allogeneic mixed islet-lymphocyte cultures (MILC). Proliferative responses of allogeneic lymphocytes to UV-irradiated FPP were very significantly decreased by 52-91% at both 300 and 500 J/m2 doses. This effect was observed from 1 to 10 days following UV irradiation and was not modulated by exposure of the tissues to gamma-interferon. We conclude that UVB-irradiation of FPP at a dose of 300 J/m2 does not alter its endocrine function and growth and is effective in reducing tissue immunogenicity. This treatment may be a useful approach for fetal islet transplantation in large animal models.

Animals↗
PubMed1995

[The effect of iontophoresis with several Ca channel blockers for PHN patients].

We performed iontophoresis with Ca channel blockers for healthy adult volunteers. In this clinical study, we used iontophoresis with Ca channel blockers. Ten out patients with PHN treated at our pain clinic were treated with iontophoresis. They were randomly assigned to one of the following four treatments: (1) 5 ml of 4% lidocaine HCl, (2) 2 mg of nicardipine HCl + 5 ml of distilled water, (3) 2 mg of verapamil HCl + 5 ml of distilled water, and (4) 2 mg of diltiazem HCl + 5 ml distilled water. Iontophoresis was performed using the above four drugs on the positive pole. Using a VAS, each patient was evaluated concerning the analgesic effect. The pain before treatment (10 points) was used as the base line. Compared with the scores before treatment, VAS scores decreased significantly after iontophoresis in all four groups. In the lidocaine group, a significant decrease in VAS scores occurred immediately after iontophoresis and lasted up to 24 hours, reaching the nadir at 2 hours. In the nicardipine group, the decrease occurred immediately after iontophoresis and lasted up to one day, reaching the nadir at four hours. In the verapamil group, the decrease started 1 hour after iontophoresis and lasted up to 48 hours, reaching the nadir at 8 hours. In diltiazem group, the decrease started 1 hour after iontophoresis and lasted up to 48 hours, reaching the nadir at 4 hours. Iontophoresis with Ca channel blockers produced a prolonged analgesic effect in PHN patients. Previously we had observed the same effect in adult volunteers. Therefore, we believe that this therapy will be clinically useful.

Aged↗
PubMed1995

HLA-DRB1*1502 allele, subtype of DR15, is associated with susceptibility to ulcerative colitis and its progression.

HLA-DRB1 allele typing was performed by the PCR-RFLP method on 59 ulcerative colitis (UC) patients and 136 healthy controls. Phenotypic frequencies of HLA-B52 and DR2 were significantly increased among the UC patients, serologically. DNA typing of HLA-DRB1 revealed that the genotypic frequency of DRB1*1502 was higher in UC than in the controls (49.2% vs 17.6%; P < 0.0001). In the analysis of clinical parameters, 82.8% of patients bearing DRB1*1502 were treated with corticosteroids. DRB1*1501 and DRB1*1502 differ in only one amino acid at residue 86 (valine vs glycine), and 66% of the UC patients carried two glycines at position 86 in the HLA-DR beta-chain (vs 51% of control; P < 0.05). These observations suggest that the presence of Gly-86 in the HLA beta-chain and surrounding amino acid sequence of HLA-DRB1*1502 is strongly associated with susceptibility to UC.

Adolescent↗
PubMed1995

The hypotensive effect of an oral adenosine analog with selectivity for the A2 receptor in the spontaneously hypertensive rat.

Adenosine is a potent arterial vasodilator that, because of a short duration of action and acid lability, is ineffective in the oral treatment of hypertension. Y-341 is a synthetic adenosine analog that is acid stable and has a prolonged duration of action. It is highly selective for the A2 receptor, which is prevalent in the vascular smooth muscle and mediates vasodilation. To determine the efficacy of Y-341 as an antihypertensive agent, the effect of Y-341 on arterial pressure was studied in spontaneously hypertensive rats (SHR) in the awake state, 3 to 4 days after arterial cannulation. Y-341 (3 mg/kg) was dissolved in 5% DMSO and administered by gavage. Blood pressure and heart rate were monitored continuously at predetermined intervals. Fifteen minutes after administration, Y-341 reduced MAP from 180 +/- 4 to 126 +/- 2 mm Hg (n = 9, P < .001). There was no significant change in heart rate. The hypotensive effect was sustained over 8 h. Vehicle (n = 5) had no effect on blood pressure. The hypotensive effect was dose dependent when the dose of Y-341 was increased from 3 to 6 and 12 mg/kg. When Y-341 was administered at 3 mg/kg/day in a single dose for 5 consecutive days, there was no significant change in the magnitude of the hypotensive response over time.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenosine↗
PubMed1995

Dissecting thoracic aorta and fusiform aneurysm of the abdominal aorta.

A 59-year-old woman with dissection of the thoracic aorta and a fusiform aneurysm of the abdominal aorta without evidence of Marfan's syndrome underwent aneurysmorrhaphy with a bifurcated expanded polytetrafluoroethylene graft. Histological specimens of the aneurysmal wall revealed the presence of idiopathic cystic medial necrosis. As typical findings of idiopathic cystic medial necrosis in the aortic wall are very rare except in cases of Marfan's syndrome, the present case is reported and the implications of this condition are discussed.

Aortic Dissection↗
PubMed1995

Separation of neutrophils from blood in human and laboratory animals and comparison of the chemotaxis.

We separated neutrophils from the peripheral blood of the human, monkey, dog, rabbit, rat, hamster, and mouse and investigated their responses to several chemotactic factors to evaluate the species-dependent difference in responsiveness. Heparinized blood was obtained by venipuncture from human, monkey, dog, and rabbit. In the rat, hamster, and mouse, the hetastarch exchange transfusion method was used to increase the neutrophil recovery. After sedimentation of red blood cells, a leukocyte suspension was layered on 5-step discontinuous Percoll gradients of densities from 1.081 to 1.097. We could routinely obtain the fractions containing neutrophils at more than 90% in all of the seven species tested. Chemotaxis assay was performed using a 48-well modified Boyden chamber. Dog neutrophils did not migrate to N-formylmethionyl-leucyl-phenylalamine (fMLP), and dog and rat neutrophil responses to leukotriene B4 (LTB4) were remarkably modest. However, neutrophils from other species showed a high reactivity to fMLP and LTB4. Although neutrophils of all species responded to human recombinant interleukin 8 (hrIL-8), the sensitivity of human and monkey neutrophils to hrIL-8 were higher as compared with other species. Human, dog, and rat neutrophils reacted most to homologous zymosan-activated serum derived respectively from human, dog, and rat serum. The present results show species-dependent differences of neutrophils in chemotactic responses.

Animals↗
PubMed1995

Ultraviolet light irradiation reduces human islet immunogenicity without altering islet function.

Allograft rejection is the major cause for failure in clinical islet transplantation for diabetic patients. A reduction of donor islet immunogenicity is potentially a useful approach for altering recipient's immune responses. Studies in animal models have shown the immunomodulatory properties of ultraviolet (UV)-B light that are beneficial for allograft survival. However, there is a narrow window between the doses required for immunomodulation and those toxic to beta-cells. In addition, this window varies between one species to another. Our study was designed to determine, in vitro, the UV-B dose for human islets that effectively reduces immunogenicity and maintains islet viability and normal function. Islets were isolated from donor pancreas by collagenase digestion and density gradient centrifugation on Euro-Ficoll. Static incubation and perifusion tests were used to measure glucose-stimulated insulin release. Viability was also assessed by histology and function of UV-irradiated islets transplanted under the renal capsule of athymic mice. The immunogenicity of UV-treated islets was determined in vitro with mixed islet lymphocyte culture using healthy human peripheral blood lymphocytes as responders. At a dose of 300 J/m2, both functional assays detected no impairment of insulin release. At 500 J/m2, a slight decrease of stimulated insulin release was observed only in the perifusion system. At the levels of 600 and 900 J/m2, a clear alteration was observed in both basal and stimulated insulin release. Islets irradiated at 300 J/m2 and transplanted into athymic mice stained strongly for insulin and responded to high glucose challenge in in vivo perfusion performed at two weeks.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1995

Quantitative analysis of the gastric ulcer healing process using video endoscopic pseudocolor imaging systems.

We developed an endoscopic pseudocolor imaging system in cooperation with Olympus Optical. This system was used for color processing of ulcer images observed over time using an electronic endoscope with measurement capability. The patients were receiving ranitidine (group R) or lansoprazole (group L) for ulcer treatment. By this method it is possible to differentiate between the types of healing tissue by their color. The total area of regions with a high degree of redness in the pseudocolor processed images was measured with a digitizer, and the hemoglobin-rich area (HA) in the regenerated epithelium was determined for the two groups. In the second week of drug administration, the HA was significantly larger in group L, at 170.70 +/- 64.70 mm2, than in group R, at 22.61 +/- 5.72 mm2 (p < 0.05). The hemoglobin rate was significantly higher in group L, at 0.90 +/- 0.02 (p < 0.01) at 2 weeks and 0.94 +/- 0.02 (p < 0.05) at 4 weeks, than in group R, at 0.72 +/- 0.06 and 0.86 +/- 0.05 at 2 and 4 weeks, respectively.

2-Pyridinylmethylsulfinylbenzimidazoles↗
PubMed1995

Clinical, microbiological and host defense parameters associated with a case of localized prepubertal periodontitis.

A 4-year-old Japanese boy was referred to Osaka University Dental Hospital because of severe mobility and pain of the right lower primary canine. The canine had severe bone loss and a pocket depth exceeding 5-6 mm. The left lower canine showed slight mobility and moderate alveolar bone loss. The other primary teeth showed no pathogenic findings. The subgingival microflora from the right lower canine was dominated by gram-negative rods, especially capnocytophaga and fusobacterium, while actinomyces sp. were the most common gram-positive bacteria. While neutrophil functions of the patient were within the normal ranges of healthy subjects, some lymphocyte functions such as IL-2 production and IgG and IgM syntheses were lower in the patient. 7 months after the extraction of the right lower primary canine, the patient complained of pain around the right lower primary lateral incisor. In 3-4 weeks, the alveolar bone was lost rapidly and mobility of the lower anterior teeth increased significantly. The primary lateral incisor was extracted and the other primary teeth were treated by sealing and systemic and local administration of antibiotics. After treatment, the lower anterior teeth became less mobile and the gram-positive cocci predominated.

Actinomyces↗
PubMed1995

Alteration of spleen lymphocyte populations in rats with arthritis induced by muramyl dipeptide analogue or complete adjuvant.

To examine the involvement of lymphocytes in the development of MDP-Lys(L18)-induced arthritis (MIA) in rats and the exacerbation of MIA by cyclosporin A (CsA), we analysed the spleen lymphocyte subset using monoclonal antibodies and flow cytometry during the development of arthritis and compared the results with those found in adjuvant-induced arthritis (AIA). Subcutaneous injection of MDP-Lys(L18) 4 mg/kg to male Lewis rats for 14 days caused very slight and quite clear increases in tarsal joint thickness on days 8 and 15, respectively. This increase was significantly enhanced by co-administration of CsA 10 mg/kg on both of these days. Adjuvant intracutaneously injected once increased the thickness only on day 15, and this was completely inhibited by CsA. The populations of CD4+ and CD8+ cells were increased and decreased, respectively, increasing the CD4+/CD8+ ratio, from day 8 in MIA. CsA enhanced the MDP-Lys(L18)-induced changes in these populations and caused additional decreases in the number of CD5+ cells. Only the CD4+ cell population was increased on day 15 in AIA, and this increase was inhibited by CsA. These results suggest that the spleen lymphocyte subsets in MIA have a different role from those in AIA, and that the contribution of enhancement of the subset changes to the exacerbating effect of CsA on MIA.

Acetylmuramyl-Alanyl-Isoglutamine↗
PubMed1995

Serum concentration of intercellular adhesion molecule-1 in patients with hepatocellular carcinoma is a marker of the disease progression and prognosis.

Serum levels of soluble forms of intracellular adhesion molecule-1 (sICAM-1) and lymphocyte function-associated antigen-3 (sLFA-3) in 122 patients with chronic liver disease including hepatocellular carcinoma (HCC) were measured by enzyme-linked immunosorbent assays. Serum levels of sICAM-1 in patients with HCC were significantly higher than those of chronic hepatitis (CH) and cirrhosis. On the other hand, serum levels of sLFA-3 in patients with HCC were almost the same as those of cirrhosis. Western blot analyses showed that molecular sizes of sICAM-1 and sLFA-3 detected in the sera were 90 kd and 50 kd, respectively, indicating that both molecules include whole extracellular domains. In patients with HCC, circulating sICAM-1 levels were significantly (P < .001) correlated with tumor volume (r = .50), total bilirubin (r = .38), serum aspartate aminotransferase levels (r = .51), and gamma-globulin (r = .63). Furthermore, serum sICAM-1 levels were significantly elevated in patients with multiple HCC (tumor number > 3) or HCC with tumor embolus in the first branch or trunk of portal vein. Survival periods were analyzed in relation to serum sICAM-1 levels in patients with HCC who had been treated by transcatheter arterial chemoembolization. The HCC patients with < 1,000 ng/mL of serum ICAM-1 showed significantly (P = .0005) longer survival than those with higher levels of the molecule. The same results were obtained when only patients with moderately differentiated HCC were analyzed (P = .02). Analyses by Cox's proportional hazard model showed that sICAM-1 is a significant (P = .032) prognostic factor for patients with HCC.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1995

[Clinical analysis of the surgical therapy of DeBakey type I acute aortic dissection].

We investigated relation of operative mortality with factors such as during from onset to operation, cardiac tamponade, age (more than 70 years old), aortic regurgitation, and shock. Fourteen patients underwent emergent surgery for DeBakey type I acute aortic dissection. These patients were the basis for this reports. Operative mortality was 43% (6/14). Although not statistically significant, there was a trend toward preoperative cardiac tamponade, namely the patients with preoperative tamponade had a poor prognosis. Causes of death were as follows, two patients related to the residual false lumen, two patients to surgical procedure, one patients to ischemic heart and one to mis-swallowing after operation. Among two patients who related to the residual false lumen, one died of rupture of the descending aorta that the clamping was performed during operation and the other occlusion of superior mesenteric artery 43 days after operation. Causes of deaths in patients in relation with surgical procedure were brain death and postoperative bleeding in 1 each. We concluded that the residual false lumen is a risk factor in the peri-operative stage.

Adult↗