Biomedical subjects

M Ishida

Publications and source records attributed to M Ishida.

At least 73 records · Page 4Linked to original sources

PubMed2000

[Vitrectomy for the treatment of expulsive hemorrhage].

PURPOSE: To evaluate the surgical outcome of vitrectomy in the treatment of expulsive hemorrhage associated with intraocular surgery. METHODS: We reviewed 12 eyes from 12 patients with expulsive hemorrhage, occurring after or during cataract extraction (4 eyes), phacoemulsification (2 eyes), glaucoma filtering surgery (4 eyes), or vitrectomy (2 eyes). Mean follow-up period was 21 months. RESULTS: The retina was reattached in 6 eyes (50%) after the initial surgery and ultimately in 9 eyes (75%). Three eyes, which failed to achieve retinal reattachment, resulted in phthisis bulbi. Final visual acuity was 0.1 or belter in 4 eyes and 0.01 to 0.09 in 4 eyes. The incidence of expulsive hemorrhage was 0% for cataract surgery, 0.57% for trabeculectomy, and 0.09% for vitrectomy at Toho University Sakura Hospital. CONCLUSION: In the treatment of expulsive hemorrhage, vitrectomy is an effective surgical procedure to improve the visual function.

Adolescent↗

PubMed2000

[Evaluation of vascular endothelial function].

Endothelial function was evaluated in renal and forearm vessels from patients with essential hypertension. First, the increase in renal blood flow evaluated by the clearance of para-aminohippurate, serum c-GMP and urinary NOx during L-arginine infusion was significantly attenuated in essential hypertension. This attenuated endothelium-dependent vasodilation was improved by angiotensin converting enzyme inhibitor, but unchanged by calcium antagonist. Second, the increase in forearm blood flow evaluated by plethysmography during acetylcholine infusion or reactive hyperemia was attenuated in essential hypertension. This attenuation was abolished by NO synthesis inhibitor. Forearm endothelial function was improved by angiotensin converting enzyme inhibitor, daily aerobic exercise and body weight reduction by low calorie diet. In conclusion, endothelium-dependent vasodilation was attenuated in renal and forearm vasculature of essential hypertensives via reduction of NO synthesis. This attenuation can be improved by several treatments.

Acetylcholine↗

PubMed2000

Multivariate analysis of long-term results after an axillobifemoral and aortobifemoral bypass in patients with aortoiliac occlusive disease.

BACKGROUND: Controversy still remains regarding the long-term results and indications for axillofemoral bypass (AxFB). A comparison of axillobifemoral bypass (AxBFB) and aortobifemoral bypass (ABFB) was thus conducted to determine whether AxFB is an acceptable alternative vascular procedure to anatomic bypass for high-risk patients. METHODS: Sixty-three patients who underwent a total of 25 AxBFBs and 38 ABFBs for aortoiliac occlusive disease were reviewed retrospectively, and both univariate and multivarate analyses were perfomed. RESULTS: The overall survival was 82.8% at five years. A univariate analysis revealed significantly lower survival rates for patients with limb-threatening ischemia, coronary disease, and cerebrovascular disease. A multivariate analysis disclosed no significant factors influencing survival rates. The overall primary patency was 79.8% at five years. The primary patency rates for AxBFB (67.7% at five years) were significantly lower than for ABFB (88.5% at five years) based on a univariate analysis (p=0.0045). In addition, the secondary patency rates for AxBFB (80.3% at five years) were significantly lower than for ABFB (96.5% at five years, p=0.0025). A multivariate analysis disclosed significantly lower primary patency rates for grafts with a higher angiographic outflow score and simultaneous infrainguinal reconstructive procedures, but the differences between AxBFB and ABFB were not significant. CONCLUSIONS: The survival and primary patency for the AxBFB group were both inferior to the ABFB group, however a multivarate analysis disclosed no significant differences between the two groups. Poor femoral run-off and the presence of synchronous infrainguinal reconstructive procedures significantly affected graft patency, and these factors modulated the patency of AxBFB. AxFB for aortoiliac occlusive disease is therefore considered to be an acceptable procedure in appropriately selected patients.

Adult↗

PubMed1999

TIP120B: a novel TIP120-family protein that is expressed specifically in muscle tissues.

TATA-binding protein (TBP) forms complexes with various nuclear proteins and plays roles in all eukaryotic transcription. We previously identified TBP-interacting protein 120 (TIP120) from rat liver. TIP120 stimulates in vitro transcription generally. Homologs of TIP120 exist in various higher eukaryotes including D. melanogaster, C. elegans, and A. thaliana. Here, we isolated cDNA of a novel rat TIP120-like protein, named TIP120B. Rat TIP120B was composed of 1,235 amino acids and was 60% identical to the original TIP120 (re-named TIP120A). However, TIP120B gene was expressed specifically in the muscle tissues, which was contrary to the ubiquitous expression of TIP120A. Moreover, TIP120B protein was observed exclusively in the muscle tissues. TIP120B is therefore suggested to be a muscle-specific protein. Northern blot analysis of the mouse embryo revealed that the expression of TIP120B was temporarily increased during the embryogenesis, whereas TIP120A maintained a constant expression level. Pull-down assay using GST-fused TBP demonstrated that TBP specifically associated with TIP120B in the nuclear extract. These results indicate that TIP120B is a muscle-specific TIP120 family protein and can also interact with TBP. TIP120B is supposed to have a specific role in muscle tissues, which may be diffrerent from that of TIP120A.

Amino Acid Sequence↗

PubMed1999

Analysis of the chicken TBP-like protein(tlp) gene: evidence for a striking conservation of vertebrate TLPs and for a close relationship between vertebrate tbp and tlp genes.

TLP (TBP-like protein), which is a new protein dis-covered by us, has a structure similar to that of the C-terminal conserved domain (CCD) of TBP, although its function has not yet been elucidated. We isolated cDNA and genomic DNA that encode chicken TLP (cTLP) and determined their structures. The predicted amino acid sequence of cTLP was 98 and 91% identical to that of its mammalian and Xenopus counterparts, respectively, and its translation product was ubiquitously observed in chicken tissues. FISH detection showed that chicken tlp and tbp genes were mapped at 3q2.6-2.8 and 3q2.4-2.6 of the same chromosome, respectively. Genome analysis revealed that the chicken tlp gene was spliced with five introns. Interestingly, the vertebrate tbp genes were also found to be split by five introns when we focused on the CCDs, and their splicing points were similar to those of tlp. On the contrary, another TBP-resembling gene of Drosophila, trf1, is split by only one intron, as is the Drosophila 's tbp gene. These results support our earlier assumption that vertebrate TLPs did not directly descend from Drosophila TRF1. On the basis of these results together with phylogenetical exam-ination, we speculate that tlp diverged from an ancestral tbp gene through a process of gene duplication and point mutations.

Amino Acid Sequence↗

PubMed1999

Shear stress-mediated extracellular signal-regulated kinase activation is regulated by sodium in endothelial cells. Potential role for a voltage-dependent sodium channel.

Fluid shear stress is an important regulator of endothelial cell (EC) function. To determine whether mechanosensitive ion channels participate in the EC response to shear stress, we characterized the role of ion transport in shear stress-mediated extracellular signal-regulated kinase (ERK1/2) stimulation. Replacement of all extracellular Na+ with either N-methyl-D-glucamine or choline chloride increased the ERK1/2 stimulation in response to shear stress by 1.89 +/- 0.1-fold. The Na+ effect was concentration-dependent (maximal effect, </=12.5 mM) and was specific for shear stress-mediated ERK1/2 activation as epidermal growth factor-stimulated ERK1/2 activation was unaffected by removal of extracellular Na+. Shear stress-mediated ERK1/2 activation was potentiated by the voltage-gated sodium channel antagonist, tetrodotoxin (100 nM), to a magnitude similar to that achieved with extracellular Na+ withdrawal. Transfection of Chinese hamster ovary cells with a rat brain type IIa voltage-gated sodium channel completely inhibited shear stress-mediated ERK1/2 activation in these cells. Inhibition was reversed by performing the experiment in sodium-free buffer or by including tetrodotoxin in the buffer. Western blotting of bovine and human EC lysates with SP19 antibody detected a 250-kDa protein consistent with the voltage-gated sodium channel. Degenerate polymerase chain reaction of cDNA from primary human EC yielded transcripts whose sequences were identical to the sodium channel SCN4a and SCN8a alpha subunit genes. These results indicate that shear stress-mediated ERK1/2 activation is regulated by extracellular sodium and demonstrate that ion transport via Na+ channels modulates EC responses to shear stress.

Animals↗

PubMed1999

Simple high-performance liquid chromatography determination of ampicillin in human serum using solid-phase extraction disk cartridges.

A simple and reproducible method for the analysis of ampicillin in human serum was developed. Serum samples were extracted using solid-phase extraction disk cartridges containing a sorbent of styrene divinyl/benzene. Extracts were separated by reversed-phase C18 high-performance liquid chromatography with UV detection at 220 nm. The mobile phase consisted of acetonitrile-10 mM NaH2PO4 (6.5:93.5, v/v). Using this extraction procedure, recovery from serum was 98.4+/-5.6%. The quantitation limit was 0.19 microg/ml using 0.5 ml of serum. The calibration curves from 0.19 to 9.41 microg/ml were linear with correlation coefficients of 0.999. This method is suitable for therapeutic drug monitoring of ampicillin (ABPC) after oral administration of lenampicillin hydrochloride.

Ampicillin↗

PubMed1999

Purification, crystallization, and preliminary X-ray crystallographic analysis of thermus thermophilus V(1)-ATPase B subunit.

The gene of V(1)-ATPase B subunit from the thermophilic eubacterium Thermus thermophilus has been cloned and the protein overproduced in Escherichia coli. The purified protein, with a molecular weight of 53.2 kDa, was crystallized from 10% (w/v) polyethylene glycol 1000, 120 mM magnesium chloride, and 100 mM Na-tricine, pH 8.0, by the vapor diffusion method. The crystals diffracted X-rays beyond 3.5 A on a synchrotron radiation source. The crystals belong to the monoclinic space group C2, with unit cell dimensions of a = 153.1 A, b = 129.6 A, c = 92.7 A, and beta = 100.3 degrees. Assuming that three or four molecules are contained in an asymmetric unit, the V(M) value is calculated as 2.8 or 2.1 A (3)/Da, respectively.

Crystallization↗

PubMed1999

Suppression of transforming growth factor beta and vascular endothelial growth factor in diabetic nephropathy in rats by a novel advanced glycation end product inhibitor, OPB-9195.

AIMS/HYPOTHESIS: Advanced glycation end products (AGEs) participate in the pathogenesis of diabetic nephropathy. We reported earlier that OPB-9195, a synthetic thiazolidine derivative and novel inhibitor of advanced glycation, prevented progression of diabetic glomerulosclerosis by lowering serum concentrations of advanced glycation end products and reducing their deposition in the glomeruli. Here, we examined their contribution and that of growth factors, such as transforming growth factor-beta (TGF-beta) and vascular endothelial growth factor (VEGF), to the progression of diabetic nephropathy. We also investigated the expression of type IV collagen in the kidneys of Otsuka-Long-Evans-Tokushima-Fatty (OLETF) rats, a Type II (non-insulin-dependent) diabetes mellitus model, after treatment with OPB-9195. METHODS: Using northern blots and immunohistochemical techniques, we determined the renal expression of TGF-beta and type IV collagen mRNAs and proteins in OLETF rats. We also examined OPB-9195's effects on renal expression of VEGF mRNA and protein. RESULTS: Concomitant increases in TGF-beta and type IV collagen expression were observed at each point in time in OLETF rats not given OPB-9195. In contrast, OPB-9195 treatment greatly suppressed the renal expression of TGF-beta, VEGF and type IV collagen mRNAs and proteins to that seen in non-diabetic rats. CONCLUSION/INTERPRETATION: Since OPB-9195, an AGE-inhibitor, prevented the progression of diabetic nephropathy by blocking type IV collagen production and suppressing overproduction of two growth factors, TGF-beta and VEGF, in diabetic rats, this compound warrants further investigation.

Animals↗

PubMed1999

Treatment of gastric tumors by endoscopic mucosal resection with a ligating device.

BACKGROUND: This study attempted to determine the indication for endoscopic mucosal resection with a ligating device (EMRL) and to assess the efficacy of radical (complete) resection of early gastric carcinoma and adenoma. METHODS: Sixteen patients with early gastric carcinoma (17 lesions) and 21 patients with gastric adenoma (23 lesions) underwent EMRL with an endoscope with a ligating device. After epinephrine solution was injected into the submucosa, the lesions were aspirated, ligated, and resected. RESULTS: Twelve of 17 early carcinomas (70.6%) and 18 of 23 adenomas (78.3%) were radically resected by EMRL. The average size of the resected specimens was 12.8 x 11.0 mm. The rate of successful radical resection by EMRL, including piecemeal resection, was 100% (15/15) for lesions located in the antrum, 80% (4/5) in the angle, 61.1% (11/18) in the body, and 0% (0/2) for lesions at the cardia. Repeat EMRL was performed successfully in cases of partial resection (n = 3). No serious complication was encountered. No recurrence of the tumors was identified in cases of radical resection during a median follow-up period of 22.8 months. CONCLUSION: EMRL is suitable for the treatment of gastric tumorous lesions. For the treatment of early carcinoma, well-differentiated mucosal carcinomas smaller than 10 mm located in the distal stomach represent the best indication for EMRL.

Adenocarcinoma↗

PubMed1999

Monochloramine-induced cytolysis to cultured rat gastric mucosal cells: role of glutathione and iron in protection and injury.

Helicobacter pylori (H. pylori) infection plays a role in the pathogenesis of peptic ulceration as well as active chronic gastritis. Possible mechanisms of H. pylori-induced mucosal injury include the generation of toxic monochloramine (NH2Cl) from oxidant (HOCl)--which is a product of activated neutrophils-and ammonia (NH3), which is a metabolite of H. pylori urease. To clarify mechanisms by which NH2Cl induces cytolysis, we determined the effects of glutathione (GSH) alteration and iron chelation on NH2Cl-induced damage in cultured rat gastric mucosal cells, because these are involved in oxidant injury. Cytotoxicity was quantified by chromium 51 release from prelabeled cells that were exposed to NH2Cl or hydrogen peroxide (H2O2). Although both NH2Cl and H2O2 caused a time-related and dose-dependent increase in 51Cr release, NH2Cl was more cytotoxic than H2O2. Pretreatment with extracellular GSH caused a right shift of the dose-response curve for NH2Cl, whereas pretreatment with diethyl maleate (a depletor of cellular GSH) rendered cells less resistant to NH2Cl. Iron chelation with 1,10-phenanthroline or deferoxamine failed to influence NH2Cl injury, whereas such treatment was protective against H2O2. Intracellular GSH seems to play an important role as a potent defense system against NH2Cl, as observed in H2O2-induced damage. However, the mechanisms of NH2Cl-induced damage seem to be distinctly different from cytolysis by H2O2 in terms of the mediation of cellular iron.

Animals↗

PubMed1999

Inhibition of uptake and release of a novel mGluR agonist (L-F2CCG-I) by anion transport blockers in the rat spinal cord.

A new metabotropic glutamate receptor (mGluR) agonist, (2S,1'S,2'S)-2-(2-carboxy-3,3-difluorocyclopropyl)glycine (L-F2CCG-I), induces a priming effect on (RS)-alpha-aminopimelate in the isolated spinal cord of newborn rats. Similar to (RS)-alpha-aminopimelate, L-glutamate (30-100 microM) neither affected spinal reflexes nor the resting membrane potentials of motoneurones, but preferentially potentiated the depression of monosynaptic excitation caused by L-F2CCG-I (0.4 microM). Following L-F2CCG-I treatment (1-2 microM), L-glutamate decreased the monosynaptic spinal reflexes in a concentration dependent manner, indicating a priming' effect of L-F2CCG-I. Thus L-glutamate is completely compatible with (RS)-alpha-aminopimelate in revealing the priming effect. An anion transport blocker, 4,4'-dinitrostilbene-2,2'-disulphonic acid (DNDS) (100 microM), markedly inhibited both the response to (RS)-alpha-aminopimelate and the induction of the L-F2CCG-I priming effect. The data suggest that L-F2CCG-I is Cl- -dependently incorporated into certain stores, and that (RS)-alpha-aminopimelate or L-glutamate must stimulate the release of L-F2CCG-I from the storage site. There were pharmacological similarities between the quisqualate and L-F2CCG-I priming effect. The physiological significance of the quisqualate or L-F2CCG-I priming is not yet established. L-F2CCG-I would be expected to be a useful pharmacological probe for elucidating the mechanism of the priming.

Amino Acids, Dicarboxylic↗

PubMed1999

Area- and lamina-specific organization of a neuronal subpopulation defined by expression of latexin in the rat cerebral cortex.

The aim of the present study was to investigate the density, laminar distribution, size, morphology, and neurotransmitter phenotype of rat cortical neurons expressing latexin, an inhibitor of carboxypeptidase A. Immunohistochemical analyses established that latexin-immunoreactive neurons are restricted essentially to the infragranular layers of lateral cortical areas in the rat. The overall density, laminar or sublaminar localization, and cell size distribution of latexin-positive neurons differed substantially across cytoarchitectonic areas within lateral cortex. Numerous latexin-positive neurons had the morphology of modified pyramidal cells especially of layer VI. The vast majority of latexin-positive neurons were glutamate-immunoreactive in the six lateral neocortical areas examined, while neurons immunoreactive for both latexin and GABA were virtually absent. Thus the majority of latexin-positive neurons are likely to be excitatory projection neurons. The area- and lamina-specific distribution of the latexin-expressing subpopulation of glutamate-immunoreactive neurons is a distinctive feature that may contribute to the functional specialization of the lateral cortical areas.

Animals↗

PubMed1999

Actions of 3-[2-phosphonomethyl[1,1-biphenyl]-3-yl]alanine (PMBA) on cloned glycine receptors.

1. PMBA is a novel antagonist of strychnine-sensitive glycine receptors in the rat spinal cord, however, its mode of action is unknown. The actions of PMBA on rat glycine receptor alpha1 and alpha2 homomers in Xenopus oocytes were studied under two-electrode voltage-clamp. 2. Co-application of PMBA and glycine to both alpha1 and alpha2 homomers yielded inward currents which decayed to a steady-state. Responses rose slowly to the same steady-state amplitude following a 2 min pre-incubation in PMBA. Strychnine, but not picrotoxinin, showed similar antagonism to PMBA. The potency of PMBA was independent of membrane potential between -100 and 0 mV. 3. When tested against EC50 concentrations of glycine, PMBA was almost equally potent on alpha1 (IC50, 406+/-41 nM: Hill coefficient, 1.5+/-0.2) and alpha2 (IC50, 539+/-56 nM; Hill coefficient, 1.4+/-0.2) homomers. 4. PMBA (1-I0 microM) and strychnine (200 nM) reduced the potency of glycine and the amplitude of the maximal agonist response of alpha1 and alpha2 homomers. In 10 microM PMBA, two distinct classes of glycine response were observed on alpha2, only a single class of responses were observed on alpha1. 5. There are similarities in PMBA and strychnine antagonism, although these compounds are structurally distinct. The possibility that PMBA interacts at two binding sites which differ in alpha1 and alpha2 subunits is discussed. PMBA may provide a lead structure for novel antagonists with which to investigate structural differences in glycine receptor at alpha1 and alpha2 subunits.

Animals↗

PubMed1999

A new 200 kV Omega-filter electron microscope.

A new 200 kV Omega-filter electron microscope was developed under a project supported by a Grant-in-Aid for Specially Promoted Research of the Ministry of Education, Science, Sports and Culture of Japan. The performance of the microscope is described.

Journal Article↗

PubMed1999

Development of a high energy resolution electron energy-loss spectroscopy microscope.

We have developed a high energy resolution electron energy-loss spectroscopy (EELS) microscope, which can take spectra from specified small specimen areas and specified small reciprocal space areas to investigate detailed electronic structures. The EELS microscope is equipped with retarding Wien filters as the monochromator and the analyser. The filters are designed to achieve a stigmatic focus. The energy resolutions are 12 meV and 25 meV for cases without and with a specimen, respectively. Spatial and momentum resolutions are 30-110 nm in diameter and 1.1 nm-1 in angular diameter, respectively. EELS spectra are presented to show the performance of this instrument.

Journal Article↗

PubMed1999

Clinical efficacy of prosthetic mandibular advancement on obstructive sleep apnea syndrome.

In order to clarify the efficacy and indication of prosthetic mandibular advancement (PMA) on obstructive sleep apnea syndrome (OSAS), we made a comparison of both the polysomnographic findings and the upper airway configuration between before and during PMA on 19 OSAS patients. During PMA, there was a significant decreased apnea hypopnea index compared to before treatment. The changes in magnetic resonance imaging of the upper airway during sleep with PMA indicated that the treatment is regarded to be the first choice for OSAS patients with glossopharyngeal obstruction. In addition to that, the treatment might be considered for use in velopharyngeal obstruction.

Airway Resistance↗

PubMed1999

Properties of endothelium and smooth muscle cells in canine femoral arteries after lumbar sympathectomy.

OBJECTIVE: To find out whether the lumbar sympathectomy modulated the endothelial function (as measured by nitric oxide (NO) and prostacyclin (PGI2), and blood flow in the canine femoral artery. DESIGN: Laboratory experiments. SETTING: Teaching hospital, Japan. ANIMALS: 16 mongrel dogs. INTERVENTION: Unilateral sympathectomy from L3 to L6. MAIN OUTCOME MEASURES: Five weeks later, the changes in blood flow, the endothelium-dependent responses and the PGI2 production in the canine femoral arteries were measured. RESULTS: The median (range) blood flow of left (denervated) and right (innervated) femoral arteries was 162 ml/min (122-330) and 65 ml/min (40-92), respectively. There was a significant difference between the two groups (p < 0.01). The endothelium-dependent relaxations to acetylcholine, adenosine diphosphate (ADP) and A23187 were comparable. The amounts of PGI2 produced in the two groups were similar. Direct relaxation in response to sodium nitroprusside was also similar in the two groups. CONCLUSIONS: Lumbar sympathectomy did not alter the endothelial function, although the median blood flow in the denervated femoral arteries was significantly higher than in the innervated ones. The continuous vasodilatation after sympathectomy may be a more potent factor in the regulation of vascular tonus than the physiological regulation of NO and PGI2.

Animals↗