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Biomedical subjects

M Iwata

Publications and source records attributed to M Iwata.

At least 55 records · Page 3Linked to original sources
PubMed2001

[Minocycline-induced pneumonitis presenting as multiple ring-shaped opacities on chest CT, pathologically diagnosed bronchiolitis obliterans organizing pneumonia (BOOP)].

A 39-year old woman was admitted to our hospital because of cough and abnormal shadows on chest radiographs. She had been treated for 5 months for acne vulgaris with minocycline hydrochloride (MINO). Chest computed tomographic (CT) scans showed multiple ring-shaped opacities in both lungs. Bronchoalveolar lavage disclosed an increase in the total number of cells and a marked increase of lymphocytes. A lung specimen obtained by transbronchial lung biopsy (TBLB) was pathologically diagnosed as bronchiolitis obliterans organizing pneumonia (BOOP). Withdrawal of minocycline led to rapid remission without treatment. The clinical course and histological findings for TBLB suggested that this case was minocycline-induced BOOP. Several cases with minocycline-induced pneumonitis have been reported. However, there are few reported cases of minocycline-induced BOOP, the present case being only the second found in the literature.

Adult↗
PubMed2001

[Roles of posterior parietal cortex in stereopsis: characteristics of responses of axis-orientation-selective neurons in monkey caudal intraparietal area].

Patients with parietal lesions may fail to adjust the orientation of their hand to that of a target object, or may make errors in judging the orientation of a bar. This suggests that the parietal cortex has a function in the discrimination of the orientation of objects. In this study we investigated the responses of axis-orientation-selective neurons in caudal intraparietal (CIP) area to stereoscopic stimuli. Among the characteristics we investigated responses to the length and thickness of objects, sensitivity to binocular disparity, and position invariance in depth. Computer generated stereoscopic stimuli were presented to the monkey on a 70 inch screen. Most of the neurons responded better to long or narrow stimuli. All neurons which were orientation selective only in the frontal plane were not disparity sensitive. Most of the neurons which were orientation selective in the sagittal or horizontal plane were sensitive for binocular disparity. The majority of these neurons had wide receptive fields and their responses were position-invariant. These results suggest that the axis-orientation-selective neurons in CIP area encode the orientation of the longitudinal axis of objects in 3-dimensional space.

Animals↗
PubMed2001

[Intestinal permeability in Crohn's disease and effects of elemental dietary therapy].

Enteral intake of non-metabolic monosacharide and disaccharide, followed by measurement of the urinary excretion ratio of the two, is a method used to investigate intestinal permeability. L/R ratio (lactulose/1-rhamnose urinary excretion ratio) is considered an indicator of permeability of the small intestine. An increased L/R ratio is caused by mucosal disorders of the small intestine. The L/R ratio in all patients (n = 92) with Crohn's disease was 0.079 +/- 0.081 (mean +/- S.D.), which was significantly higher than the value in normal controls (0.027 +/- 0.009, n = 20, p < 0.05). In 39 patients with Crohn's disease, we assessed intestinal permeability before after treatment with an elemental diet, and during remission. The L/R ratio was 0.120 +/- 0.092, before treatment and 0.065 +/- 0.097 after treatment (p < 0.05), showing increased intestinal permeability before elemental dietary treatment. During remission, the L/R ratio was 0.035 +/- 0.028; this did not differ significantly from the value obtained after treatment. We conclude that intestinal permeability is useful for investigating disease activity in patients with Crohn's disease.

Adolescent↗
PubMed2001

Induction of thymic apoptosis by Shiga toxin from Escherichia coli O157:H7 in vivo and in vitro.

It is not known how Shiga toxins (Stxs), which are major virulence factors of enterohemorrhagic Escherichia coli, can affect the host immune system. We investigated the effect of Stx2 on murine thymic cells in vivo and in vitro. After intraperitoneal administration of Stx2, the body weight of mice (BW) and the organ index of thymocytes (OIT) gradually decreased from day 1 to day 4. Apoptosis of thymocytes, assessed by TUNEL staining, and DNA fragmentation assay, was marked on day 3 and day 4. Decrease in BW and OIT due to Stx2 was antagonized by the simultaneous administration of murine anti-Stx2 IgG antibody with Stx2. In vitro administration of Stx2 also induced apoptosis of cultured thymocytes on day 3 and day 4 in a dose-dependent fashion. These results showed that Stx2 directly caused apoptosis of thymocytes in vivo and in vitro. Our findings imply that StA2 may be intimately related to pathogenesis of E. coli O157:H7 infection, by causing apoptosis of thymus.

Animals↗
PubMed2001

The effect of stress on toxicant-dependent cytochrome p450 enzyme responses in the Arctic charr (Salvelinus alpinus).

In the present study we investigated the effect of stress and cortisol on cytochrome P450 (CYP) expression in Arctic charr exposed to benzo[a]pyrene (BaP). Expression of hepatic CYP1A and CYP3A was monitored 8 d after a single oral dose of BaP (10 mg/kg fish) and compared to that in unexposed fish. During this period the fish were subjected to one of the following stress regimes: no stress, no stress and cortisol implantation, 10 min of daily handling and confinement stress, and confinement stress during the last 6 h before sampling. In BaP-exposed fish daily stress resulted in significantly lower (53%) CYP1A protein levels as compared to those in unstressed fish. For CYP1A catalytic activity (measured as 7-ethoxyresorufin-O-deethylase [EROD] activity), the suppressive response to stress was less pronounced. These results contrast to previous findings of a potentiation by corticosteroids on xenobiotic-dependent CYP1A induction in vitro in cultured fish hepatic cells. No effects of high cortisol levels or BaP were found on the steroid-metabolizing CYP3A enzyme levels. The lack of any alterations in the CYP3A protein level indicates that CYP3A expression is not inducible by cortisol in the Arctic charr under the conditions used here. The conclusion was made that short-term stress associated with sampling (i.e., 6 h of confinement stress before sampling) of wild charr does not compromise the EROD activity as a reliable biomarker.

Adaptation, Physiological↗
PubMed2001

[Evaluation of thiazolidinedione derivative drugs for safety].

The first thiazolidinedione derivative drug for diabetes, troglitazone, was found to cause fatal hepatotoxicity, although it was judged as safe during the clinical trial. Subsequently, pioglitazone has been clinically used both in Japan and U.S. and has had no fatal cases but caused heart failure. Therefore, careful follow up observation is necessary in these drugs by checking liver function tests and cardiac function.

Animals↗
PubMed2001

[Ergocalciferol Reference Standard (Control 001) of National Institute of Health Sciences].

The raw material of ergocalciferol was examined for the preparation of "Ergocalciferol Reference Standard (Control 001)". Analytical data obtained were: melting point, 114.8 degrees C; UV and infrared spectra, the same as those of JP Ergocalciferol Reference Standard (Control 971); specific absorbance, E1ca1% = 471(265 nm); optical rotation, [alpha]D20 = +102.4 degrees; thin-layer chromatography, no impurities were detected until 100 micrograms; high-performance liquid chromatography (HPLC), total amount of impurities estimated to be less than 0.1%. Based on the above results, the raw material was authorized as the Japanese Pharmacopoeia Ergocalciferol Reference Standard (Control 001).

Chemical Phenomena↗
PubMed2001

[Alprostadil Reference Standard (Control 001) of National Institute of Health Sciences].

The raw material of Alprostadil was examined for the preparation of "Alprostadil Reference Standard (Control 001)". Analytical data obtained were: IR spectrum, same as that of the Alprostadil Reference Standard (Control 923); thin-layer chromatography, no impurities were detected until 20 micrograms; high-performance liquid chromatography (HPLC), total amount of impurities estimated to be less than 0.2%. Based on the above results, the raw material was authorized as the Japanese Pharmacopoeia Alprostadil Reference Standard (Control 001).

Alprostadil↗
PubMed2001

[Cholecalciferol Reference Standard (Control 001) of National Institute of Health Sciences].

The raw material of cholecalciferol was examined for the preparation of "Cholecalciferol Reference Standard (Control 001)". Analytical data obtained were: melting point, 83.2 degrees C; UV and infrared spectra, the same as those of JP Cholecalciferol Reference Standard (Control 971), respectively; specific absorbance at 265 nm, E1ca1% = 478; optical rotation, [alpha]D20 = +108.6 degrees; thin-layer chromatography, no impurities were detected until 100 micrograms; high-performance liquid chromatography (HPLC), total amount of impurities estimated to be less than 0.05%. Based on the above results, the raw material was authorized as the Japanese Pharmacopoeia Cholecalciferol Reference Standard (Control 001).

Chemical Phenomena↗
PubMed2001

[Betamethasone Sodium Phosphate Reference Standard (Control 001) of National Institute of Health Sciences].

The raw material of betamethasone sodium phosphate was examined for the preparation of the "Betamethasone Sodium Phosphate Reference Standard (Control 001)". The analytical data obtained were: melting point, 207.2 degrees C; pH, 8.1; optical rotation, [alpha]D20 = +104.4 degrees; UV spectrum, lambda max of 242 nm and specific absorbance in water at 242 nm = 272.9; IR spectrum, specific absorptions at 3386.9, 1721.7, 1663.3, 1620.4, 1605.0, 1094.3, 985.8, 889.8 cm-1; free phosphoric acid, 0.3%; thin-layer chromatography, one impurity was detected until 200 micrograms; high-performance liquid chromatography, total amount of impurities estimated to be less than 0.5%; water, 9.2%. Based on the above results, the raw material was authorized as the Betamethasone Sodium Phosphate Reference Standard (Control 001) of the National Institute of Health Sciences.

Betamethasone↗
PubMed2001

[Hydrocortisone Sodium Phosphate Reference Standard (Control 001) of National Institute of Health Sciences].

The raw material of hydrocortisone sodium phosphate was examined for the preparation of the "Hydrocortisone Sodium Phosphate Reference Standard (Control 001)". The analytical data obtained were: pH, 8.3: optical rotation, [alpha]D20 = +126.2 degrees; UV spectrum, lambda max of 248 nm and specific absorbance in water at 248 nm = 338.6; IR spectrum, same as that of the Hydrocortisone Sodium Phosphate Reference Standard (Control 891); free phosphoric acid, 0.2%; free hydrocortisone, 0.01%; thin-layer chromatography, no impurity was detected until 200 micrograms; high-performance liquid chromatography, total amount of impurities estimated to be less than 0.2%; residual solvent, 0.0% (acetone) and 0.02% (ethanol); loss on drying, 1.5%. Based on the above results, the raw material was authorized as the Hydrocortisone Sodium Phosphate Reference Standard (Control 001) of the National Institute of Health Sciences.

Chromatography, High Pressure Liquid↗
PubMed2001

[Beclometasone Dipropionate Reference Standard (Control 011) of National Institute of Health Sciences].

The raw material of beclometasone dipropionate was examined for the preparation of the "Beclometasone Dipropionate Reference Standard (Control 011)". The analytical data obtained were: melting point, 208.8 degrees C; optical rotation, [alpha]D20 = +91.7 degrees; IR spectrum, same as that of the Beclometasone Dipropionate Reference Standard (Control 865); thin-layer chromatography, one impurity was detected until 40 micrograms; high-performance liquid chromatography, total amount of impurities estimated to be less than 0.5%; loss on drying, 0.6%. Based on the above results, the raw material was authorized as the Beclometasone Dipropionate Reference Standard (Control 011) of the National Institute of Health Sciences.

Beclomethasone↗
PubMed2001

[Dexamethasone Sodium Phosphate Reference Standard (Control 001) of National Institute of Health Sciences].

The raw material for dexamethasone sodium phosphate was examined for the preparation of the "Dexamethasone Sodium Phosphate Reference Standard (Control 001)". The analytical data obtained were: pH, 8.0; optical rotation, [alpha]D20 = +79.6 degrees; UV spectrum, lambda max of 242 nm and specific absorbance in water at 242 nm = 313.6; IR spectrum, same as that of the Dexamethasone Sodium Phosphate Reference Standard (Control 893); free phosphoric acid, 0.06%; free dexamethasone, 0.07%; thin-layer chromatography, no impurities were detected until 100 micrograms; high-performance liquid chromatography, total amount of impurities estimated to be less than 0.2%; residual solvent, 4.3% (ethanol); water, 7.3%. Based on the above results, the raw material was authorized as the Dexamethasone Sodium Phosphate Reference Standard (Control 001) of the National Institute of Health Sciences.

Chromatography, High Pressure Liquid↗
PubMed2001

[Glycyrrhizinic Acid Reference Standard (Control 001) of National Institute of Health Sciences].

The raw material of glycyrrhizinic acid was examined for preparation of the "Glycyrrhizinic Acid Reference Standard". The analytical data obtained were: UV spectrum: lambda max, 251 nm; and specific absorbance (E1ca1%) in ethanol at 251 nm, 146; IR spectrum, specific absorptions at 1714, 1655, 1215, and 1170 cm-1; and the spectrum of raw material was consistent with that of Standard (Control 991). Also, thin-layer chromatography, no impurity was detected; high-performance liquid chromatography, several impurities were detected. The amount of each impurity was estimated at less than 0.2% and total amount of impurities was less than 0.4%. Based on the above results, the candidate material was authorized as the Glycyrrhizinic Acid Reference Standard (Control 001) of the National Institute of Health Sciences.

Chromatography, High Pressure Liquid↗
PubMed2001

[Berberine Hydrochloride Reference Standard (Control 001) of National Institute of Health Sciences].

The raw material of Berberine Hydrochloride was examined for preparation of the "Berberine Hydrochloride Reference Standard". The analytical data obtained were: UV spectrum: lambda max, 420, 345, 263 and 228 nm and specific absorbance (E1ca1%) in ethanol at each lambda max, 155, 724, 796 and 820, respectively; IR spectrum, specific absorptions at 2844, 1635, 1569, and 1506 cm-1; and the spectrum of raw material was consistent with that of Standard (Control 941). Also, thin-layer chromatography, an impurity was detected; high-performance liquid chromatography, several impurities were detected. The amount of each impurity was estimated at less than 0.1% and the total amount of impurities was less than 0.2%. Based on the above results, the candidate material was authorized as the Berberine Hydrochloride Reference Standard (Control 001) of the National Institute of Health Sciences.

Berberine↗
PubMed2001

[Clinical features of a senior patient with Williams syndrome].

We experienced a case of 62-year-old woman who was admitted for the evaluation of her trembling hands. She was diagnosed as Williams syndrome (WS) by fluorescent in situ hybridization (FISH) analysis. She was short in stature, had a characteristic face and moderate mental retardation, whereas she was talkative and gregarious. She also presented impaired visuospatial cognition, cerebellar ataxia and tremor like involuntary movement of the hands. No remarkable abnormality is noted in MRI of the brain. MRA study of the brain revealed the arteriosclerotic vascular change, such as elongation of basilar artery and dilatation of bilateral carotid arteries. Heterozygous microdeletion of chromosome 7q11.23 of this patient is typical for WS, the delction including elastin (ELN) and LIMK 1 gene. Although she was complicated by diabetes mellitus and hyperlipidemia, she had no cardiovascular abnormalities like supravalvular aortic stenosis (SVAS), and survived to her age in good condition. The tremor-like involuntary movement disappeared after her discharge and its mechanism remains to be elucidated.

Brain↗
PubMed2001

[Strategy for circulatory disturbance].

A meta-analysis by the Cochrane Stroke Group (CSG) showed that thrombolytic therapy increased deaths as well as symptomatic and fatal intracranial hemorrhage within the first seven to 10 days and at final follow-up, although these risks are offset by a reduction in disability in survivors, so that there is overall a significant net reduction in the proportion of patients dead or dependent. Trials testing intravenous (i.v.) tPA suggest that it may be associated with less hazard and more benefit. A recent trial demonstrated that intra-arterial pro-urokinase improved long-term outcome in patients with M 1 or M 2 occlusion within 6 hours of onset. Trials of the third generation of thrombolytic agents are ongoing in patients with acute ischemic stroke. The latest CSG's meta-analysis showed that immediate anticoagulant therapy in patients with acute ischemic stroke was not associated with net short or long-term benefit because there was no evidence that anticoagulant therapy reduced deaths or non-fatal stroke during treatment or patients dead or dependent at the end of follow-up. However, an i.v. low-molecular-weight heparinoid showed a trend toward improving long-term outcome in subgroup of patients with atherothrombotic stroke. The thrombin inhibitor argatroban was proven to be comparable to the thromboxane A2 synthetase inhibitor ozagrel in the effect on the outcome at one month in patients with atherothrombotic stroke within 48 hours of onset in Japan, and a trial of the agent is ongoing in patients with ischemic stroke within 12 hours of onset in the United States. Two large trials of aspirin in patients with ischemic stroke within 48 hours of onset indicated that aspirin had a modest effect on reducing patients dead or dependent at the end of follow-up. An international trial of abciximab, a monoclonal antibody directed against platelet glycoprotein IIb/IIIa, is ongoing in patients with ischemic stroke within 6 hours of onset.

Abciximab↗