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Biomedical subjects

M Ueda

Publications and source records attributed to M Ueda.

At least 163 records · Page 9Linked to original sources
PubMed2001

Characterization of ascorbate peroxidases from unicellular red alga Galdieria partita.

Galdieria partita, a unicellular red alga isolated from acidic hot springs and tolerant to sulfur dioxide, has at least two ascorbate peroxidase (APX) isozymes. This was the first report to demonstrate that two isozymes of APX are found in algal cells. Two isozymes were separated from each other at the hydrophobic chromatography step of purification and named APX-A and APX-B after the elution order in the chromatography. APX-B accounted for 85% of the total activity. Both isozymes were purified. APXs from Galdieria were monomers whose molecular weights were about 28,000, similar to stromal APX of higher plants. APX-A cross-reacted with monoclonal antibody raised against APX of Euglena gracilis in immunoblotting, but APX-B did not, although the antibody can recognize all other APXs tested. The amino-terminal sequences of APX-A and -B from Galdieria had some homology with each other but little homology with those from other sources. Their Km values for ascorbate and hydrogen peroxide were comparable with those of APX from higher plants. Unlike the green algal enzymes, the donor specificities of Galdieria APXs were as high as those of plant chloroplastic APX. On the contrary, these APXs reduced tertiary-butyl hydroperoxide as an electron acceptor as APXs from Euglena and freshwater Chlamydomonas do. The inhibition of APX-A and -B by cyanide and azide, and characteristics of their light absorbance spectra indicated that they were heme peroxidases.

Amino Acid Sequence↗
PubMed2001

Role of potassium channels in isoflurane- and sevoflurane-induced attenuation of hypoxic pulmonary vasoconstriction in isolated perfused rabbit lungs.

BACKGROUND: Although potassium channels are thought to be responsible for the initiation of hypoxic pulmonary vasoconstriction (HPV), their role in the HPV-inhibitory effect of volatile anesthetics is unclear. The current study tested if the HPV-inhibitory effect of isoflurane and sevoflurane can be affected by changing the potassium-channel opening status with specific potassium-channel inhibitors in isolated rabbit lungs. METHODS: Isolated rabbit lungs were divided into eight groups (n = 6 each in isoflurane groups and n = 8 in sevoflurane groups): those receiving no inhibitor treatment = control-isoflurane and control-sevoflurane groups; those treated with an adenosine triphosphate-sensitive potassium (K(ATP))-channel inhibitor, glibenclamide = glibenclamide-isoflurane and glibenclamide-sevoflurane groups; those treated with a high-conductance calcium-activated potassium (K(Ca))-channel inhibitor, iberiotoxin = iberiotoxin-isoflurane and iberiotoxin-sevoflurane groups; and those treated with a voltage-sensitive potassium (Kv)-channel inhibitor, 4-aminopyridine = 4-aminopyridine-isoflurane and 4-aminopyridine-sevoflurane groups. The effect of anesthetic on HPV was tested by exposure of the lungs to isoflurane at a concentration of 0, 0.5, 1, or 2 minimum alveolar concentration, or to sevoflurane at a concentration of 0, 0.5, 1, or 1.62 minimum alveolar concentration. The relation between anesthetic concentrations and the HPV response was analyzed by the Wagner equation. RESULTS: The inhibition of Kv channels by 4-aminopyridine and K(Ca) channels by iberiotoxin augmented the HPV response. The isoflurane-induced attenuation of HPV was attenuated by voltage-sensitive potassium-channel inhibition with 4-aminopyridine, potentiated by K(Ca)-channel inhibition with iberiotoxin, but not affected by K(ATP)-channel inhibition with glibenclamide. The sevoflurane-induced attenuation of HPV was not affected by any of the potassium-channel inhibitors. CONCLUSIONS: Isoflurane may modulate the HPV response partially through K(Ca) and Kv channels, but sevoflurane may attenuate the HPV response through other pathways rather than through the currently investigated potassium channels in isolated rabbit lungs.

Algorithms↗
PubMed2001

Effects of aging on muscle T2 relaxation time: difference between fast- and slow-twitch muscles.

RATIONALE AND OBJECTIVES: To determine whether the T2 relaxation time of skeletal muscle is affected by aging and to compare the effects of aging between fast- and slow-twitch muscles in a human study. To investigate the mechanisms of age-related changes in T2 relaxation time in an animal (mouse) study. METHODS: T2 relaxation times of the soleus (slow-twitch, rich in type I fiber) and gastrocnemius (fast-twitch, rich in type II fiber) muscles were examined in 59 healthy human subjects, 22 to 76 years of age, by clinical magnetic resonance imaging. In mice, T2 relaxation times, fat ratios, and extracellular space ratios (extracellular space/intracellular plus extracellular space) of the spinalis (fast-twitch, rich in type II fiber) muscles were also examined (group of 7 old mice, 24-26 months; group of 7 young mice, 8-10 weeks). RESULTS: In the human study, the T2 relaxation time of the gastrocnemius muscle increased significantly with aging (r = 0.53, P < 0.01) while that of the soleus muscle did not. In the animal study, the T2 relaxation time of the spinalis muscle was significantly longer (P < 0.05) and the extracellular space ratio of the spinalis muscle significantly wider (P < 0.01) in old than in young mice. No significant difference in fat ratio was observed between old and young mice. A significant, positive correlation was seen between the extracellular space ratio and T2 relaxation time (r = 0.84, P < 0.01). CONCLUSIONS: The T2 relaxation time of fast-twitch muscle increases with aging, due mainly to increased extracellular space, reflecting age-related type II fiber atrophy.

Adult↗
PubMed2001

Genetically controlled self-aggregation of cell-surface-engineered yeast responding to glucose concentration.

We constructed an arming (cell-surface-engineered) yeast displaying two types of agglutinin (modified a-agglutinin and alpha-agglutinin) on the cell surface, with agglutination being independent of both mating type and pheromones. The modified a-agglutinin was artificially prepared by the fusion of the genes encoding Aga1p and Aga2p. The modified a-agglutinin could induce agglutination of cells displaying Agalpha1p (alpha-agglutinin). The upstream region of the isocitrate lyase gene of Candida tropicalis (UPR-ICL), active at a low glucose concentration, was used as the promoter to express the modified a-agglutinin- and alpha-agglutinin-encoding genes. The arming yeast displaying both agglutinins agglutinated and sedimented in response to decreased glucose concentration. When the glucose concentration was high, the arming yeast grew normally. In the late log phase, when the glucose concentration became very low, agglutination occurred suddenly and drastically and yeast cells sedimented completely. Sedimentation was confirmed by weighing the aggregated cells after filtration of the broth. Strains in which aggregation can be genetically controlled can be used in industrial processes in which the separation of yeast cells from the supernatant is necessary.

Agglutination↗
PubMed2001

Role of alveolar macrophages in Candida-induced acute lung injury.

Recent studies have shown that alveolar macrophages (AMs) not only act as phagocytes but also play a central role as potent secretory cells in various lung diseases, including pneumonia and acute respiratory distress syndrome. The behavior of AMs during disseminated candidiasis, however, is insufficiently elucidated. This study is the first to report disseminated candidiasis in AM-depleted mice and to analyze the effect of AMs on Candida-induced acute lung injury. While all AM-sufficient mice died by day 2 after infection with Candida albicans, no mortality was observed among AM-depleted mice. Unexpectedly, the CFU numbers of C. albicans isolated from the lungs of AM-depleted mice were significantly higher than those for C. albicans isolated from AM-sufficient mice. The lung wet-to-dry weight ratio was lower for AM-depleted mice than for AM-sufficient mice, although this difference was not significant. We found that bronchoalveolar lavage fluid (BALF) from AM-depleted mice in candidemia contained fewer neutrophils than BALF from AM-sufficient mice. In addition, myeloperoxidase activities in lung homogenates of AM-depleted mice were significantly lower than those in homogenates of AM-sufficient mice. A significant decrease in levels of murine macrophage inflammatory protein 2 (MIP-2), a potent chemoattractant for neutrophils, was noted in lung homogenates from AM-depleted mice compared with levels in homogenates from AM-sufficient mice. Immunohistochemical studies using anti-MIP-2 antibodies revealed that AMs were the cellular source of MIP-2 within the lung during candidemia. We observed that AM depletion decreased levels of AM-derived neutrophil chemoattractant, alleviated acute lung injury during candidemia, and prolonged the survival of mice in candidemia, even though clearance of C. albicans from the lungs was reduced.

Acute Disease↗
PubMed2001

Biochemical alterations during medication withdrawal in Parkinson's disease with and without neuroleptic malignant-like syndrome.

The object was to assess alterations in CSF concentrations of monoamine metabolites during withdrawal of medication in patients with Parkinson's disease in relation to the presence or absence of episodes resembling neuroleptic malignant syndrome (NMS). This syndrome is a fatal condition developing after neuroleptic therapy, and a neuroleptic malignant-like syndrome (NMLS) may also occur after withdrawal of antiparkinsonian drugs in patients with Parkinson's disease. Previous biochemical assays showed that the CSF concentration of the dopamine metabolite homovanillic acid (HVA) is an independent prognostic factor for development of NMLS in patients with Parkinson's disease. In the present study, CSF concentrations of HVA, the noradrenaline (norepinephrine) metabolite 3-methoxy-4-hydroxyphenylethylene glycol, and the serotonin metabolite 5-hydroxyindole acetic acid were assayed using high performance liquid chromatography with electrochemical detection. The study population consisted of nine patients with Parkinson's disease with NMLS and 12 without NMLS, in whom metabolites were assayed during both withdrawal and remedicated periods. Concentrations of HVA in the CSF were significantly lower during the withdrawal period than the medicated period regardless of whether patients developed NMLS, and HVA concentrations were comparably increased after remedication in both groups. However, HVA concentrations were significantly lower in patients with NMLS than in those without NMLS during both withdrawal and medicated periods. Other metabolites showed no significant differences. The present data provide further biochemical evidence for extremely suppressed central dopaminergic activity during NMLS, which may indicate a narrow safety margin for medication withdrawal in patients with Parkinson's disease.

Aged↗
PubMed2001

C-type natriuretic peptide induces redifferentiation of vascular smooth muscle cells with accelerated reendothelialization.

We recently reported that C-type natriuretic peptide (CNP) occurs in vascular endothelial cells and acts as a vascular-type natriuretic peptide. In the present study, we stimulated the cGMP cascade in proliferating smooth muscle cells (SMCs), in which particulate guanylate cyclase-B, the specific receptor for CNP, is predominantly expressed, by use of an adenovirus encoding rat CNP cDNA (Ad.CNP). In the Ad.CNP-treated cultured SMCs, CNP caused the growth inhibition of SMCs at G(1) phase with an early increase of p21(CIP1/WAF1) expression and subsequent upregulation of p16(INK4a). The expression of smooth muscle myosin heavy chain-2, which is the molecular marker of highly differentiated SMCs, was reinduced in the Ad.CNP-treated SMCs. The Ad.CNP-treated SMCs also reexpressed particulate guanylate cyclase-A, which shows high affinity to atrial and brain natriuretic peptide and is exclusively expressed in well-differentiated SMCs. CNP, which was overexpressed in rabbit femoral arteries in vivo at the time of balloon injury, significantly suppressed neointimal formation. Furthermore, an enhancement of the expression of smooth muscle myosin heavy chain-2 occurred in the residual neointima. In addition, early regeneration of endothelial cells was observed in the Ad.CNP-infected group. Thus, stimulation of cGMP cascade in proliferating dedifferentiated SMCs can induce growth inhibition and redifferentiation of SMCs with accelerated reendothelialization.

Adenoviridae↗
PubMed2001

Neuroprotective effect of immunosuppressant FK506 in transient focal ischemia in rat: therapeutic time window for FK506 in transient focal ischemia.

Tacrolimus (FK506), an immunosuppressant currently used in clinic, is known to have neuroprotective properties. However, effects in focal ischemia are shown only in a endothelin induced middle cerebral artery (MCA) occlusion model or with filament technique at a relatively high dose. We have previously shown that FK506 had significant protective effects at a low dose of 0.3 mg kg(-1) when administered immediately after ischemia. In this study, we explored the therapeutic time window of FK506 at this low dose, in a transient focal ischemia model using filament technique. Male Sprague-Dawley rats were subjected to 2 h MCA occlusion and subsequent reperfusion. They received FK506 or vehicle (0.3 mg kg(-1)) i.v. at 30, 60 or 120 min after induction of ischemia, and were decapitated 24 h after ischemia. FK506 injected at 30 and 60 min significantly reduced cortical infarction volume (FK506 vs. vehicle; 30 min: 95 +/- 33 mm3 vs. 170 +/- 62 mm3, p < 0.05; 60 min: 93 +/- 45 mm3, vs. 168 +/- 35 mm3, p < 0.05, respectively). FK506 was ineffective when given at 120 min after ischemia. FK506 had no effect on edema formation, nor on the infarct volume in striatum. The therapeutic time window for this low dose of FK506 given i.v. is between 60 and 120 min in this model.

Animals↗
PubMed2001

Vascular smooth muscle cell phenotypes in primary pulmonary hypertension.

Primary pulmonary hypertension (PPH) is associated with specific structural alterations, including cellular intimal thickening, intimal fibrosis, and plexiform lesions. To determine the phenotypes of smooth muscle cells (SMCs) in such lesions, the authors conducted an immunohistochemical analysis of lung tissues from two patients with PPH, using two antimuscle actin antibodies, HHF35 and CGA7, and two anti-SMC myosin heavy chain markers, anti-SM1 and anti-SM2 antibodies and related antibodies. Cells that stained positive (+) with HHF35, CGA7, anti-SM1, and anti-SM2 were considered to be SMCs of a mature state. Conversely, those that stained positive with HHF35 and anti-SM1, but weakly positive (+/-) or negative (-) with CGA7 and anti-SM2, were considered to be SMCs exhibiting an immature state. Cellular intimal thickening was composed of SMCs of an immature phenotype (HHF35+, CGA7+/-, SM1+, SM2+/-), accompanied by the expression of fibronectin and the presence of macrophages; intimal fibrosis contained mature SMCs (HHF35+, CGA7+, SM1+, SM2+); and plexiform lesion consisted of proliferative endothelial cells (von Willebrand factor-positive cells, proliferating cell nuclear antigen-positive cells) and underlying immature SMCs (HHF35+, CGA7-, SM1+, SM2-) associated with fibronectin expression and macrophage infiltration. These findings suggest that smooth muscle cells with specific phenotypes may contribute to the development of specific vascular lesions in primary pulmonary hypertension.

Actins↗
PubMed2001

Acidic amino acid transport characteristics of a newly developed conditionally immortalized rat type 2 astrocyte cell line (TR-AST).

To characterize acidic amino acid transport in type 2 astrocytes, we established conditionally immortalized rat astrocyte cell lines (TR-AST) from newly developed transgenic rats harboring temperature-sensitive SV40 large T-antigen gene. TR-AST exhibited positive immunostaining for anti-GFAP antibody and A2B5 antibody, characteristics associated with type 2 astrocytes, and expressed glutamine synthetase. Acidic amino acid transporters, GLT-1 and system xc-, which consists of xCT and 4F2hc, were expressed in all TR-ASTs by RT-PCR. On the other hand, GLAST expression was found in TR-AST3 and 5. The characteristics of [3H]L-glutamic acid (L-Glu) uptake by TR-AST5 include an Na+-dependent and Na+-independent manner, concentration-dependence, and inhibition by L-aspartic acid (L-Asp) and D-aspartic acid (D-Asp). The corresponding Michaelis-Menten constants for the Na+-dependent and Na+-independent process were 36.3 microM and 155 microM, respectively. [3H]L-Asp and [3H]D-Asp uptake by TR-AST5 had an Na+-dependent and Na+-independent manner. This study demonstrated that GLT-1, system xc-, and GLAST were expressed in TR-AST, which has the characteristics of type 2 astrocytes and is able to transport acidic amino acids.

Amino Acid Transport Systems, Acidic↗
PubMed2001

Expression of a gene encoding chitinase (pCA 8 ORF) from Aeromonas sp. no. 10S-24 in Escherichia coli and enzyme characterization.

A gene encoding chitinase from Aeromonas sp. no. 10S-24 was expressed using pTrc99A in Escherichia coli JM 105 which yielded a 5-fold higher activity than when pUC19 was used. Three different truncated enzymes (SA-1, SA-2 and SA-3) were obtained after purification. Their isoelectric points were 7.0, 6.9, and 6.7, respectively. The enzymes showed two optimum pHs, 4.0 and 7.0, when incubated with ethylene glycol chitin as the substrate, and were stable over a wide pH range (3.0-9.0). The optimum temperature was 60 degrees C and the enzymes were stable up to 50 degrees C. The chitinases exhibited wide substrate specificities for chitin-related compounds.

Journal Article↗
PubMed2001

A comparative study on the integration of exogenous DNA into mouse, rat, rabbit, and pig genomes.

Transgenic mammals, from small laboratory rodents to domestic animals, have been successfully produced to date, but their production efficiency within or across species has been variable. This is probably due to the differences in the type of injected DNA and/or technical procedures employed in each laboratory, as well as the reproductive characteristics of the species. Here we report the direct comparison of the efficiencies of producing transgenic mice, rats, rabbits and pigs by one technician using a fusion gene composed of the bovine alpha S1-casein promoter and human growth hormone (hGH) gene. Before the fusion gene was injected into the zygotes, high magnitude centrifugation to visualize the pronuclei was necessary for all of the pig zygotes and one-third of the rabbit zygotes, but not for mouse and rat zygotes. Post-injection survival of the mouse zygotes (67.1%) was lower than those of the rat, rabbit and pig zygotes (89.6 to 100%). The volume change of the pronucleus following DNA injection was the lowest in mice (50% increase), moderate in rabbits (148% increase), and the most prominent in rats (238% increase). The data from only 1 pig zygote indicated a 22% increase in the pronucleus volume by DNA injection. The PCR analyses of the tail DNA of new born offspring indicated that 0.8% (4/493), 4.8% (22/463), 0.8% (3/367) and 0.9% (2/221) of the injected eggs in mice, rats, rabbits and pigs, respectively, developed into transgenic offspring. Some of the founder animals in all four species expressed the transgene in the mammary gland which was confirmed in hGH mRNA by RT-PCR and/or hGH peptide in Witch's milk with ELISA. These results suggest that the maximum volume of DNA solution injectable into the pronucleus is a possible factor explaining the species differences in the production of transgenic animals.

Animals↗
PubMed2001

Production of transgenic rats using young Sprague-Dawley females treated with PMSG and hCG.

The aim of this study was to examine the effects of gonadotrophin treatments on estrus synchronization and superovulation in young Sprague-Dawley (SD) rats that had not yet exhibited defined estrus cycles (5 to 7 weeks old), and to produce transgenic rats using these females as embryo donors and recipients. In Experiment 1, female rats were injected with PMSG and hCG (12.5, 25, 50 and 100 IU/kg each) and were mated with stud males. The reproductive performance of young rats were highest when PMSG and hCG at doses of 25 IU/kg each were injected (delivery rate 87.5%, nursing rate 92.9%). In Experiment 2, female rats were injected with PMSG and hCG (100, 150 and 300 IU/kg each) to induce superovulation. More eggs were recovered from the rats injected with PMSG and hCG at 150 and 300 IU/kg than from those treated with 100 IU/kg (33.4 and 41.3 vs. 13.3 eggs per female, respectively; p < 0.05). In Experiment 3, pronuclear-stage zygotes from 150 IU/kg PMSG/hCG-treated rats were used for microinjection of the fusion gene of bovine alpha S1-casein gene promoter and human growth hormone gene (2.8 kb), and the microinjected zygotes were transferred into the oviduct ampullae of the 25 IU/kg PMSG/hCG-treated rats. Seventeen transgenic rats were obtained from the 334 DNA-injected zygotes (5.1%). These results indicate that recipients and embryo donors for the production of transgenic rats can be prepared by the appropriate PMSG and hCG treatments of young SD rats, regardless of their estrus stages.

Animal Husbandry↗
PubMed2001

Spontaneous neoplastic lesions in aged Sprague-Dawley rats.

Neoplastic lesions were observed in untreated aged Sprague Dawley (SD) rats throughout their lifespan starting at 5 weeks. Their mean survival times were 89 to 105 weeks of age. The total tumor incidences were 70 to 76.7% and 87 to 95.8% in males and females, respectively. The common neoplasmas were pituitary adenoma and adrenal pheochromocytoma in both sexes, testicular Leydig cell tumor in males and mammary gland tumors, thyroidal C-cell adenoma and uterine stromal polyp in females.

Adenoma↗
PubMed2001

Arrangement of D-periodic collagen fibrils and association of proteoglycans with fibrils in the synovium of the mouse temporomandibular joint.

The present study was performed to examine changes in the arrangement of D-periodic collagen fibrils in the synovium of the growing temporomandibular joint in mice. At 1 week of age, the mandibular condyle was undeveloped, and only a few collagen fibrils were recognizable in the subintimal layer of the synovium. At 8 weeks, the mandibular condyle was structurally developed with an increase of collagen fibrils in the synovium; a fully mature condyle was observed at 6 months of age. The close association of proteoglycans with collagen fibrils in the synovium of the growing joint was examined by both conventional and energy-filtering transmission electron microscopy of cupromeronic blue-stained specimens. Proteoglycans were associated with D-periodic collagen fibrils in the short filamentous form in random fashion at 1 week of age, but in a regular pattern with D-periodicity at 6 months. These associations in the synovium could be correlated with the mechanical character of the temporomandibular joint.

Age Factors↗
PubMed2001

Development of endoscopic surgery for the minimally invasive treatment of digestive and other diseases.

Minimally invasive surgery has rapidly changed the performance of surgical practice in a wide range of surgical specialities in the last decade of the 20th century. The marked progress in endoscopic surgery has been conducted especially in general and digestive surgery. The Department of Surgery, School of Medicine, Keio University has contributed to the development and establishment of endoscopic surgery in every subspeciality of general and digestive surgery. Our achievements include the development of original methods for laparoscopic wedge gastrectomy and endoscopic thyroidectomy, establishment of surgical techniques in endoscopic surgery for esophageal, gastric, colorectal and hepatobiliary diseases, and the introduction of robotics and tele-communicative technologies to endoscopic surgery.

Digestive System Surgical Procedures↗
PubMed2001

[Statistics on the operations at the Department of Urology, Fuji City General Hospital during a 10-year period (January 1989-December 1998)].

A 10-year statistic survey was carried out on the operations performed at the Department of Urology, Fuji City General Hospital. The total number of operations was 1,862 cases during 10 years. The number of operations for malignant tumors has increased since 1994 year after year. Transurethral resection of prostate for benign prostatic hyperplasia has decreased since 1992, with the advent of the alpha 1-blocker. The patients with urolithiasis are being cured by extracorporeal shock wave lithotripsy on an outpatient basis, at our hospital, except in special cases. It was suggested to be safe, so the complications needing admission appeared in only 1.2% of the cases.

Female↗