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Biomedical subjects

A Itoh

Publications and source records attributed to A Itoh.

At least 55 records · Page 3Linked to original sources
PubMed2000

Amperometric detection studies of Nafion/indium hexacyanoferrate film for the determination of electroinactive cations in ion chromatography.

An amperometric detector based on the chemical modification of Nafion and indium (III) hexacyanoferrate (II, III) thin film (Nafion/In-CN-Fe) onto a glassy carbon (GC) electrode, was first successfully used for the determination of electroinactive cations (Li+, Na+, K+, Rb+, Cs+, NH4+) in single column ion chromatography (IC). A set of well-defined peaks of electroinactive cations was obtained. The detection limits of the cations are 8.9 x 10(-6) mol/L for Li+, 2.3 x 10(-6) mol/L for Na+, 5.2 x 10(-6) mol/L for K+, 4.8 x 10(-6) mol/L for Rb+, 4.0 x 10(-6) mol/L for Cs+ and 5.3 x 10(-6) mol/L for NH4+ at a single-to-noise ratio of 3. The proposed method was quick, sensitive and simple. The cations in rainwater and mineral water were successfully analyzed by this method.

Acid Rain↗
PubMed2000

Polydiphenylamine-dodecyl sulfate films for the simultaneous amperometric determination of electroinactive anions and cations in ion-exclusion cation-exchange chromatography.

An amperometric detector with two working electrodes both modified with polydiphenylamine-dodecyl sulfate (PDPA-DS) was successfully used for the simultaneous determination of electroinactive anions (SO42-, Cl-, NO3-) and cations (Na+, NH4+ and K+) in single-column ion-exclusion cation-exchange chromatography (IEC-CEC). The PDPA-DS chemical modified electrode (CME) was based on the incorporation of dodecyl sulfate (DS) into PDPA by electropolymerization of diphenylamine in the presence of sodium dodecyl sulfate. The electrochemical responses against the anions and cations at the PDPA-DS CME in differential pulse voltammetry were studied. A set of well-defined peaks of electroinactive anions and cations were obtained. The anions and cations were detected conveniently and reproducibly in a linear concentration range 0.01-5.0 mmol/L and their detection limits were in the range 5-9 micromol/L at a signal-to-noise ratio of 3 (S/N = 3). The proposed method was quick, sensitive and simple and was successfully applied to the analysis of lake water samples. The working electrode was stable over one week period of operation with no evidence of chemical and mechanical deterioration.

Journal Article↗
PubMed2000

Use of ECG-gated SPET to assess the evolution of perfusion after acute myocardial infarction.

Serial improvement in myocardial perfusion images from the acute or subacute to the chronic stage of acute myocardial infarction (AMI) has been attributed to improved coronary microcirculation or cell function after acute ischaemia and reperfusion. However, conventionally used non-gated imaging cannot eliminate the effect of improved regional contraction. We studied the possibility that such scintigraphic improvement reflects the functional recovery by using ECG-gated myocardial perfusion imaging with technetium-99m sestamibi. Nineteen AMI patients who received acute reperfusion therapy underwent ECG-gated myocardial single-photon emission tomography (SPET) in the subacute and chronic stages. Serial changes in regional image count distributions were analysed on the non-gated, end-diastolic (ED) and end-systolic (ES) images by using segmental mean percent peak activity (MPA) and AMPA (MPA in chronic stage - MPA in subacute stage) on bull's-eye polar maps. These changes were compared with those in regional wall motion on biplane left ventriculography (LVG) from the acute (just after reperfusion) to the chronic stage. During the follow-up, regional wall motion remained the same in 42 (group A) but improved in 17 (group B) of the 59 ischaemically compromised segments. MPA showed no improvement in group A but significant improvement in group B on the non-gated and ES images (P<0.0001 and P<0.001, respectively). However, MPA on the ED images showed no improvement in either group. In the follow-up study of AMI, the scintigraphic improvement documented on the non-gated myocardial images appears to be mainly related to the recovery of wall thickening and not to a real improvement in myocardial perfusion. Therefore, ECG-gated myocardial imaging, which enables simultaneous assessment of changes in perfusion and contraction, is preferable to conventional non-gated imaging for follow-up of AMI.

Acute Disease↗
PubMed2000

Transpapillary biopsy in gallbladder disease.

BACKGROUND: Endoscopic biopsy is routine in gastrointestinal disease; similarly, histopathologic diagnosis is desirable in gallbladder disease. In this study we examined the clinical usefulness and the problems associated with transpapillary gallbladder biopsy. METHODS: Transpapillary gallbladder biopsy was attempted in 9 patients with gallbladder disease. After inserting a catheter sheath into the gallbladder using a guidewire via the transpapillary route without sphincterotomy, we inserted a biopsy forceps into the lumen of the sheath up to the gallbladder lumen and obtained specimens. RESULTS: We could obtain sufficient specimens for histopathologic diagnosis in 8 of 9 cases (88.9%). Of the 8 successful cases, targeted specimens were obtained in 7 (87.5%). Diagnostic accuracy with respect to malignant versus benign disease was 100% (2 of 2) and 83.3% (5 of 6), respectively. There were no complications. CONCLUSION: Transpapillary gallbladder biopsy is a clinically useful technique because it facilitates histopathologic diagnosis and therefore guides the choice of therapy.

Biopsy↗
PubMed2000

Attenuation of the development of morphine dependence/tolerance by nefiracetam: involvement of adenosine 3':5'-cyclic monophosphate system.

Biochemical changes such as intracellular cAMP and Ca(2+) underlying morphine dependence and tolerance have been suggested. Therefore, we investigated the effects of nefiracetam (N-(2, 6-dimethyl-phenyl)-2(2-oxo-1-pyrrolidinyl) acetamide), which increases intracellular cAMP and Ca(2+) levels, on the development of morphine dependence and tolerance. Mice administered morphine (6 or 20 mg kg(-1)) twice daily for 5 days, showed withdrawal symptoms (jumping, diarrhea and body weight loss) after naloxone challenge (5 mg kg(-1)), indicating morphine dependence. Furthermore, tolerance to the analgesic effect of morphine was observed in these mice. Co-administration of nefiracetam (5 or 10 mg kg(-1)) with morphine during the pretreatment period, significantly reduced the signs of withdrawal symptoms, moreover, the tolerance was significantly attenuated. Elevation of cAMP levels in the cortex was observed in morphine-dependent mice, but not in mice co-administered nefiracetam. Acute administration of nefiracetam shows no effect on the withdrawal symptoms and the analgesic effect in morphine-naive mice. Theophylline (3 or 10 mg kg(-1)) tended to attenuate and enprofylline (10 or 30 mg kg(-1)) significantly attenuated the development of morphine dependence and tolerance. These findings suggest that co-administration of nefiracetam or compounds, which increase the cAMP level, may be a useful strategy for attenuating the development of morphine dependence and tolerance in the clinic.

Animals↗
PubMed2000

Two Alangium alkaloids from Alangium lamarckii.

Two new Alangium alkaloids, 1',2'-dehydrotubulosine (1) and alangine (2), were isolated from the dried fruits of Alangium lamarckii along with tubulosine (3), isotubulosine (4), deoxytubulosine, cephaeline, isocephaeline, psychotrine, neocephaeline, 10-O-demethylcephaeline, 2'-N-(1"-deoxy-1" -beta-D-fructopyranosyl)cephaeline, protoemetine, protoemetinol, salsoline, and alangiside. The structures of the new alkaloids (1 and 2) were determined by spectroscopic and chemical means.

Alkaloids↗
PubMed2000

Five phenolic glycosides from Alangium chinense.

From the dried leaves of Alangium chinense, five novel phenolic glycosides, 6'-O-galloylsalicin (1); 4',6'-di-O-galloylsalicin (2); 4',6'-O-(S)-hexahydroxydiphenoylsalicin (3); 4', 6'-O-(R)-hexahydroxydiphenoylsalicin (4); and pyrocatechol 1-O-beta-D-xylopyranosyl(1-->6)-beta-D-glucopyranoside (5) were isolated. The structures of these new compounds were determined by spectroscopic methods.

Carbohydrate Conformation↗
PubMed2000

Clinicoepidemiologic features of sudden deafness diagnosed and treated at university hospitals in Japan.

Nationwide epidemiologic surveys were done 3 times by the Research Committee of the Ministry of Health and Welfare in Japan to investigate the number of patients and clinical manifestations of idiopathic sudden sensorineural hearing loss (sudden deafness). The first, second, and third surveys were carried out during the 1970s, 1980s, and 1990s, respectively. For each patient, we have compiled data regarding age, sex, onset day, presence or absence of vertigo, and hearing ability, including initial and final audiograms, in a computer in the Nagoya University Computer Center. Regarding patients who visited university hospitals, complete data were collected for 421 subjects (age: 40.2+/-15.4 years, female: 203, male: 218) between July 1973 and June 1974, for 813 subjects (age: 45.1+/-15.4 years, female: 407, male: 406) in 1987, and for 1112 subjects (age: 49.1+/-16.0 years, female: 591, male: 521) in 1993. The number of patients with sudden deafness treated in university hospitals in Japan has increased, especially in the elderly population. This increase is associated with population increase and age-adjusted incidence rates per 100,000 in the elderly population. The initial and final hearing levels in the first survey were worse than those in the second and third surveys; there was no significant difference in hearing between the second and third surveys. The hearing levels were worse in children and elderly patients than in the other age groups.

Adolescent↗
PubMed2000

Colocalization of GP125/CD98 with tropomyosin isoforms at the cell-cell adhesion boundary.

Two monoclonal antibodies designated as 1F6 and 4B10 were obtained on screening for reactivities to CD98-associated molecules by sandwich-type enzyme-linked immunosorbent assaying using hybridoma culture supernatants as the solid phase, cell lysates as an antigen source, and a mixture of biotinylated antibodies to CD98HC as a detector. Flow cytometric analysis with microspheres in combination with 1F6, 4B10, and anti-CD98HC also indicated the association of antibody-defined antigen(s) with CD98. 1F6 and 4B10, stained fibrillate components in fixed and permeated cells but were not reactive with unfixed live cells, suggesting that epitopes reside in the cytoskeleton-associated structure in the intracellular region. Two-color immunostaining followed by confocal microscopy revealed the colocalization of the antigen with CD98 at the cell-cell adhesion boundary of HeLa cells. 1F6 detected proteins with relative molecular masses of 33,000 to 43,000 on immunoblotting analysis involving cell lysates of human and rat cell lines. Analysis with a purified tropomyosin specimen from rabbit skeletal muscle demonstrated that 1F6 and 4B10 recognize tropomyosin. Two-dimensional gel electrophoresis followed by immunoblotting analysis revealed that 1F6 recognizes various tropomyosin isoforms. These results indicated that CD98 physically associates directly or indirectly with tropomyosin, and that this association is closely related to the cell-cell interaction.

Actins↗
PubMed2000

Cytochrome P450-dependent metabolism of oxylipins in tomato. Cloning and expression of allene oxide synthase and fatty acid hydroperoxide lyase.

Allene oxide synthase (AOS) and fatty acid hydroperoxide lyase (HPL) are plant-specific cytochrome P450s that commit fatty acid hydroperoxides to different branches of oxylipin metabolism. Here we report the cloning and characterization of AOS (LeAOS) and HPL (LeHPL) cDNAs from tomato (Lycopersicon esculentum). Functional expression of the cDNAs in Escherichia coli showed that LeAOS and LeHPL encode enzymes that metabolize 13- but not 9-hydroperoxide derivatives of C(18) fatty acids. LeAOS was active against both 13S-hydroperoxy-9(Z),11(E),15(Z)-octadecatrienoic acid (13-HPOT) and 13S-hydroperoxy-9(Z),11(E)-octadecadienoic acid, whereas LeHPL showed a strong preference for 13-HPOT. These results suggest a role for LeAOS and LeHPL in the metabolism of 13-HPOT to jasmonic acid and hexenal/traumatin, respectively. LeAOS expression was detected in all organs of the plant. In contrast, LeHPL expression was predominant in leaves and flowers. Damage inflicted to leaves by chewing insect larvae led to an increase in the local and systemic expression of both genes, with LeAOS showing the strongest induction. Wound-induced expression of LeAOS also occurred in the def-1 mutant that is deficient in octadecanoid-based signaling of defensive proteinase inhibitor genes. These results demonstrate that tomato uses genetically distinct signaling pathways for the regulation of different classes of wound responsive genes.

Aldehyde-Lyases↗
PubMed2000

Action potential remodeling in the human right atrium with chronic lone atrial fibrillation.

It has been shown in animal experiments that recurrent induction of atrial fibrillation (AF) or long-lasting atrial pacing causes a shortening of the atrial effective refractory period (ERP) and action potential duration (APD) and a loss of their physiological adaptation to rate. Much remains to be clarified as to the electrical remodeling in human patients with chronic AF. We recorded monophasic action potentials (MAPs) from the right atrium at pacing cycle lengths (CLs) of 300, 333, 400, 500, 600, and 750 ms after external cardioversion in 13 patients with chronic lone AF. Their configuration was compared with those obtained from 13 control patients. APDs at 50% and 90% repolarization (APD50, APD90) at the shortest CL (300 ms) in control and AF patients were 131 +/- 14, 211 +/- 19 ms and 136 +/- 12, 210 +/- 22 ms, respectively (mean +/- SD). APDs in control patients increased linearly with increases of CL, reaching maximal values of 174 +/- 30 ms (APD50) and 277 +/- 38 ms (APD90) at a CL of 750 ms. In AF patients, the steady-state CL-APD relation was shifted downward and flattened at CLs > 500 ms; APD50 and APD90 at a CL of 750 ms were 158 +/- 19 ms, 232 +/- 28 ms, respectively. APD90s at CLs of 600 and 750 ms were significantly shorter in AF than in control patients. No statistically significant difference was obtained in APD50 between the two groups at any CL tested. MAP configuration in AF patients was characterized by an acceleration of the late repolarization. The difference between APD90 and APD50 (APD90-50) in control patients was increased with increases of CL, reaching a plateau at a CL of 600 ms. This CL dependent slowing of the late repolarization of MAPs was abolished in AF patients. The atrial ERP, measured at CLs of 400 and 600 ms, showed changes parallel to those of APD90. ERP at a CL of 600 ms in AF patients (224 +/- 13 ms) was significantly shorter than that in control patients (247 +/- 25 ms). We conclude that chronic lone AF leads to electrical remodeling in the human atrium, which causes a loss of rate response of the late repolarization of action potential, leading to a shortening of APD and ERP at slower heart rates.

Action Potentials↗
PubMed2000

[Two cases of HIV infection accompanied with borderline personality disorder].

We report here two cases of HIV infection with a borderline personality disorder. Case 1 was a 25-year-old male patient who was diagnosed with HIV infection 4 years ago. Borderline personality disorder was also diagnosed at that time. Although he was referred to our hospital in 1999, we had to refer him to another hospital for his regular outpatient hemodialysis. Case 2 was a 24-year-old male patient who had borderline personality disorder since 1996. He was diagnosed with HIV infection in 1999 and referred to our hospital. He ignored rules in visiting clinics such as prior reservations and frequently called doctors, case-workers and nurses. After several visit he intentionally took excessive sedative medicines and called a case-workers at our hospital. He was admitted to our hospital for three days. After he was discharged, we set limitations for his behavior not to harm himself and to obey the rules in visiting clinics. In other countries investigators report that borderline personality disorder is more common in HIV-infected persons. It may be because persons with borderline personality disorder are more likely to engage in high-risk sexual behavior, which is also applicable to these two cases. As HIV infection is rapidly prevailing in Japan, it is possible that the chance are that this disorder will be seen more frequently in HIV infected cases.

Adult↗
PubMed2000

Is preinfarction angina related to the presence or absence of coronary plaque rupture?

OBJECTIVE: To analyse the prodrome of acute myocardial infarction in relation to the plaque morphology underlying the infarct. DESIGN: A retrospective investigation of the relation between rupture and erosion of coronary atheromatous plaques and the clinical characteristics of acute myocardial infarction. The coronary arteries of 100 patients who died from acute myocardial infarction were cut transversely at 3 mm intervals. Segments with a stenosis were examined microscopically at 5 micrometer intervals. The clinical features of the infarction were obtained from the medical records. RESULTS: A deep intimal rupture was encountered in 81 plaques, whereas 19 had superficial erosions only. There were no differences in the location of infarction, the incidence of hypertension, diabetes mellitus, or hyperlipidaemia, diameter stenosis of the infarcted related artery, Killip class, Forrester's haemodynamic subset, or peak creatine kinase between plaque rupture and plaque erosion groups. The presence of plaque rupture was associated with significantly greater incidences of leucocytosis, current smoking, and sudden or unstable onset of acute coronary syndrome. In patients with unstable preinfarction angina, new onset rest angina rather than worsening angina tended to develop more often in the plaque rupture group than in the plaque erosion group (p = 0.08). CONCLUSIONS: Plaque rupture causes the sudden onset of acute myocardial infarction or unstable preinfarction angina, which may be aggravated by smoking and inflammation.

Aged↗
PubMed2000

A tetrahydroisoquinoline-monoterpene glucoside and an iridoid glucoside from Alangium kurzii.

From the leaves of Alangium kurzii, a new tetrahydroisoquinoline-monoterpene glucoside, 6-O-methyl-N-deacetylipecosidic acid and a new iridoid glucoside, 10-O-benzoyladoxosidic acid, were isolated along with alangiside, demethylalangiside, 6''-O-beta-D-glucosylhenryoside, uridine and four known flavonoid glycosides. The structures of new glucosides were determined on the basis of spectroscopic and chemical methods.

Acetylation↗
PubMed2000

[Synthetic organic reactions with mesoporous silicas].

Some hexagonal mesoporous silicas were attempted to use as a promoter for fine organic synthesis. Ti-HMS, a Ti-loaded hexagonal mesoporous silica, which possesses Lewis acid sites due to Ti-atom, was found to accelerate deprotection of benzyl ethers under hydrogenolytic conditions with palladium catalyst. Such acid-sensitive functional groups as silyl ether and acetal moieties in the molecule were little affected by Ti-HMS. MCM-41, a hexagonal mesoporous silica, /MeOH heterogeneous system was found to remove selectively and easily triethylsilyl (TES) group of silyl ethers of several types in the presence of t-butyldimethylsilyl (TBS) groups. FSM-16, another hexagonal mesoporous silica, was found to catalyze oxidative photodecarboxylation of alpha-hydroxy carboxylic acid and phenyl acetic acid derivatives to afford the corresponding carbonyl compounds. Furthermore, FSM-16 proved to be reuseable by recalcination at 450 degrees C after the reaction. Efficiency of these reactions was investigated concerning the solvent effect and activities of the promoters including common zeolites and ion-exchange resins.

Catalysis↗
PubMed2000

Meningitis carcinomatosa originating from an alpha fetoprotein-producing gastric cancer.

Alpha fetoprotein (AFP)-producing gastric cancer is relatively rare and meningitis carcinomatosa is similarly a rare manifestation among the neoplastic diseases. There have been no previous reports of meningitis carcinomatosa originating from AFP-producing gastric cancer. A 68-year-old man with AFP-producing gastric cancer was treated with cisplatin and doxifluridine because of multiple liver metastases. Although the liver lesion was reduced to 30% of pretreatment size after 6 courses of chemotherapy, meningitis carcinomatosa subsequently occurred. Immunostaining of AFP and magnetic resonance imaging (MRI) were useful in the diagnosis of meningitis caused by AFP producing cancer cells.

Adenocarcinoma↗