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H Masaki

Publications and source records attributed to H Masaki.

At least 145 records · Page 8Linked to original sources
PubMed1996

[A case of swallowed fish bone-induced esophageal perforation and mediastinitis treated with pedicled omental graft].

We experienced a case of 47-year-old man who suffered swallowed fish bone-induced esophageal perforation with purulent mediastinitis and underwent direct suture closure of the perforation and reinforcement with a pedicled parietal pleura four days after the onset. Postoperative esophageal suture insufficiency was occured and reoperation was performed two months after the first operation. The esophageal fistula was plugged with a pedicled omental graft successfully. The postoperative course of the patient was uneventful and he discharged 45 days after the second operation. A reinforcement by pedicled omental graft for esophageal rupture accompanied with mediastinitis was considered to be a useful procedure.

Animals↗
PubMed1995

Role of cysteine 337 and cysteine 340 in flavoprotein that functions as NADH oxidase from Amphibacillus xylanus studied by site-directed mutagenesis.

A flavoprotein from Amphibacillus xylanus catalyzes the reduction of oxygen to hydrogen peroxide. Each polypeptide chain in the tetrameric enzyme contains 5 cysteine residues. The complete reduction of enzyme by dithionite requires 6 electrons. Such behavior indicates the presence of redox centers in addition to the FAD, and these could be disulfides. In order to assess the catalytic role of disulfide in the enzyme, 2 of the cysteines (Cys-337 and Cys-340), which show a high degree of homology with alkyl hydroperoxide reductase F52a protein and thioredoxin reductase, have been changed to serines by site-directed mutagenesis of the cloned flavoprotein gene (individually and in a double mutant). Titration of the three mutant enzymes, lacking Cys-337, Cys-340, or both cysteines, requires only 2 electron eq to reach the reduced flavin state. These results indicate the absence of a redox-active disulfide and demonstrate the involvement of Cys-337 and Cys-340 in the redox-active disulfide. The catalytic activity of the three enzymes was examined by steady-state analysis. The Km for NADH and oxygen and the kcat value of these mutant enzymes were essentially the same as those of wild type. The NADH oxidase activities were also accelerated markedly in the presence of free FAD, which is the case for wild-type enzyme. The NADH:5,5'-dithiobis(2-nitrobenzoic acid) (DTNB) oxidoreductase activities of all mutant enzymes were less than 3% of the activity of wild-type enzyme. The weak DTNB reductase activities in the mutant enzymes lacking Cys-337 or Cys-340 may occur through direct reduction of the mixed disulfide Cys-337-thiol or Cys-340-thiol and nitrothiobenzoate by FADH2. However, the weak DTNB reductase activity in the mutant enzyme lacking both cysteines indicates that FADH2 can reduce either DTNB or another disulfide directly, albeit inefficiently. These results suggest intramolecular dithiol-disulfide interchange reactions in the flavoprotein.

Amino Acid Sequence↗
PubMed1995

Temperature acclimation induces light meromyosin isoforms with different primary structures in carp fast skeletal muscle.

Carp acclimated to 10 degrees C gave 69k, 66k, and 62kDa light meromyosin (LMM) fragments in SDS-PAGE, while fish acclimated to 30 degrees C gave 74k, 69k, 66k, and 62kDa fragments. The microsequence analysis revealed that the 69k and 66kDa components from the 10 degrees C-acclimated carp contained an N-terminal amino acid sequence different from that of 62kDa. The four fragments from the 30 degrees C-acclimated carp showed the same sequence as that of the 69k and 66kDa components from the 10 degrees C-acclimated carp, except that the 2nd amino acid, Ala, of the 10 degrees C-acclimated LMM was replaced by Thr. DNA fragments encoding an N-terminal region of LMM were amplified by PCR or reverse transcriptase-PCR, demonstrating that the two acclimated groups further contained several amino acids substituted.

Acclimatization↗
PubMed1995

Detection of hydrogen peroxide and hydroxyl radicals in murine skin fibroblasts under UVB irradiation.

The purpose of this study was to identify the active oxygen species generated in murine skin fibroblasts under UVB irradiation. When fibroblasts were exposed to UV light (UVA + UVB), hydroxyl radicals were detectable by ESR-spin trapping using DMPO as a spin trapping agent. Cell damage induced by UVB irradiation was prevented by addition of DMSO, a typical hydroxyl radical scavenger. Fibroblasts treated with a catalase inhibitor 3-amino-1H-1,2,4-triazole were more sensitive to UVB irradiation than untreated-cells, but the sensitivity was improved by addition of DMSO. To find the origin of the hydroxyl radicals in fibroblasts during UVB irradiation, H2O2 was determined by dihydrorhodamine 123 and it was found that the formation of H2O2 increased under UVB irradiation. These results suggest that UVB-irradiated skin fibroblasts produce H2O2 and were followed by the formation of hydroxyl radicals, probably derived from the Fenton-like reaction (H2O2 + Fe2+ --> .OH + OH- + Fe3+), which in turn damages the cells.

Animals↗
PubMed1995

Iodine-123 metaiodobenzylguanidine images reflect intense myocardial adrenergic nervous activity in congestive heart failure independent of underlying cause.

OBJECTIVES: This study was undertaken to assess myocardial adrenergic activity using iodine-123 metaiodobenzylguanidine (MIBG) imaging in patients with heart failure. BACKGROUND: In patients with congestive heart failure, adrenergic nerve activity is accelerated. However, whether myocardial adrenergic nerve activity reflects the severity of heart failure and its relation to the underlying cause have not yet been elucidated. METHODS: Planar MIBG images were obtained from 96 patients with heart failure and compared with images from 9 age-matched healthy subjects. Groups 1 and 2 included 65 patients with heart failure related to impaired myocardial function and whose left ventricular ejection fraction was < 40% (group 1 = 40 patients with dilated cardiomyopathy; group 2 = 25 patients with ischemic cardiomyopathy). Group 3 included 31 patients with heart failure related to a mechanical abnormality and whose left ventricular ejection fraction was > 40% (mitral regurgitation in 16, aortic regurgitation in 9, aortic and mitral regurgitation in 4, ruptured aneurysm of Valsalva in 2). Myocardial uptake of MIBG was calculated as the heart/mediastinal activity ratio. Storage and release of MIBG were calculated as percent myocardial MIBG washout from 15 min to 4 h after isotope injection. RESULTS: The heart/mediastinal activity ratio in the immediate images (15 min) showed a significant decrease only in patients with severe heart failure (groups 1 and 2). The myocardial washout was accelerated in all three heart failure groups. The level of myocardial washout was related to severity of heart failure and correlated well with New York Heart Association functional classification. CONCLUSIONS: In severe heart failure associated with cardiomyopathy, norepinephrine uptake is reduced. In addition, myocardial adrenergic nerve activity is accelerated in proportion to severity of heart failure, independent of the underlying cause.

3-Iodobenzylguanidine↗
PubMed1995

Protective activity of hamamelitannin on cell damage of murine skin fibroblasts induced by UVB irradiation.

The protective activities of hamamelitannin (2',5-di-O-galloyl-hamamelose) in Hamamelis virginiana L. and its related compound, gallic acid, on damaged murine skin fibroblasts induced by UVB irradiation were investigated. In order to exclude the UV absorbing effect of the compounds, the protection study was performed such that the fibroblasts were pretreated with hamamelitannin or gallic acid for 24 h before UVB irradiation. At 200 microM concentration, hamamelitannin gave the higher survival of 72.6 +/- 0.4% in comparison with that of gallic acid (35.5 +/- 1.0%), while UVB absorbers such as 2-ethylhexyl p-methoxycinnamate and hexylbenzoate did not show such protection. The scavenging activities of hamamelitannin and gallic acid against active oxygens such as superoxide anion radicals, hydroxyl radicals and singlet oxygens were evaluated using electron spin resonance (ESR-spin trapping method). Hamamelitannin and gallic acid showed potent scavenging activities against all active oxygens tested. Furthermore, the association of hamamelitannin to fibroblasts was examined by comparing it with that of gallic acid, and the following results were obtained: (1) hamamelitannin reduces the reaction rate of liposome entrapped-nitroblue tetrazolium (NBT) with external superoxide anions, and (2) several glycosides associate with fibroblasts. From these results, it was concluded that hamamelitannin protects murine fibroblasts against external active oxygens by associating with the cell surface through its sugar moiety.

Animals↗
PubMed1995

[A clinical study of gastrointestinal flora in patients with, or without MRSA colonization in the upper-respiratory tract after introduction of preventive measures of hospital infection].

In early 1980's methicillin-resistant Staphylococcus aureus (MRSA) was reported as a major pathogenic organism of geriatric hospital infection in Japan. At the same time in the A geriatric hospital MRSA infection was prevalent. To decrease nosocomial infections some active preventive measures against hospital infection were taken since Oct. 1991. After introduction of preventive measures of hospital infection in geriatric ward (190 beds) nosocomial bacteremia and pneumonia were markedly decreased in comparison to the episode number before introduction of prevention. However several patients with MRSA colonization were observed every month. The aim of this clinical study was to clear how frequent MRSA was isolated from the gastric juice and stool. Any MRSA was not observed in 63 cultured stool, but just one MRSA was isolated in patients with MRSA colonization. On the other hand gram-negative organisms, which were E. coli, P. aeruginosa, P. mirabilis etc., were frequently observed in cultured stool. In conclusion, we considered frequency of MRSA colonization in gastrointestinal space was not so high but rather very low.

Adult↗
PubMed1995

[Decrease of nosocomial bacteremia and nosocomial pneumonia after introduction of preventive measures of hospital infection].

In the early 1980's methicillin-resistant staphylococcus aureus (MRSA) was reported as a major pathogenic organism of geriatric hospital infection in Japan. At the same time in the A geriatric hospital MRSA infection was prevalent. To decrease nosocomial infections some active preventive measures against hospital infection were taken since Oct. 1991. About a year before introduction of prevention of hospital infection in the geriatric ward (190 beds) of A hospital 193 episodes of nosocomial bacteremia were observed. However a year after introduction of preventive measures episodes of nosocomial bacteremia were decreased to less than a half (45.6%) in comparison to the number before introduction of prevention. As a causative organism gram-positive bacteria including MRSA were markedly decreased. Major portals of entry of bacteremia (74.9%) were urinary-tract system, intravenous hyperalimentation (IVH) catheter, and pressure sores. MRSA-positive pressure sores were decreased to 20.4% of those before prevention. On the other hand 87 episodes of nosocomial pneumonia were observed before prevention. However a year after introduction of preventive measures episodes of nosocomial pneumonia were decreased to less than a half (44.8%) in comparison to the number before introduction of prevention. After prevention MRSA and mixed infection of P. aeruginosa and MRSA were markedly decreased. The decrease of bacteremia and nosocomial pneumonia were caused by cleaning hands, the preventive measures for decrease and improvement of pressure sores, cleaning the upper respiratory tract for prevention of lower respiratory-tract infection cleaning floors and education of the staff, etc.

Adult↗
PubMed1995

Effect of Guglielmi detachable coils on experimental carotid artery aneurysms in primates.

BACKGROUND AND PURPOSE: Clinical experience has established that intravascularly placed metal coils can be a useful treatment for cerebral vascular aneurysms. However, the mechanism by which the coils induce occlusion of the aneurysm is unclear. Appropriate use of this promising treatment modality requires basic understanding of the occlusive process. We used an animal model system of experimentally induced carotid aneurysms to investigate the initial events induced by Guglielmi detachable coils (GDCs), as well as the subsequent vascular changes induced by the coils over time. METHODS: We induced 23 aneurysms in the carotid arteries of 16 Japanese monkeys. Nineteen aneurysms were then occluded with GDCs placed via endovascular surgery; 4 aneurysms served as controls. We then used gross and microscopic pathological examination, angiography, and scanning electron microscopy to assess the effects of the GDC. RESULTS: In the first few hours after placement of the GDC in the experimental aneurysms, we observed leukocyte attachment and deposition of fibrinlike materials and other proteins. By 4 days after coil placement, leukocytes and fibroblasts were observed in the thrombus. By 2 weeks after coil placement, there was evidence of an endothelial-like covering of the coils. At 3 months after coil placement, we observed development of an arterial media in the occluded aneurysms. CONCLUSIONS: The GDCs initiated a cellular response within several hours of aneurysm occlusion. By 2 weeks after coil placement, endothelialization was proceeding, and by 3 months after occlusion, remodeling of the aneurysm had progressed to produce a media-like structure in the former aneurysm.

Aneurysm↗
PubMed1995

Active-oxygen scavenging activity of plant extracts.

To find antioxidative compounds present in plants, 65 types of plant extract were tested using the neotetrazolium method for evidence of superoxide anion-scavenging effects and 7 plant extracts were selected for further investigation. The activity of active-oxygen scavengers such as superoxide anion radicals, hydroxyl radicals, singlet oxygens and lipid peroxides in the 7 plant extracts (Aeseclus hippocastanum L., Hamamelis virginiana L. Polygonum cuspidatum Sieb., Quercus robur L., Rosemarinous officinalis L., Salvia officinalis L. and Sanguisorba officinalis L.) was examined in detail by both ESR spin-trapping and malondialdehyde generation. Furthermore, the active-oxygen scavenging activity of these plant extracts was evaluated using a murine dermal fibroblast culture system. Both Aeseclus hippocastanum L. and Hamamelis virginia L. were found to have strong active-oxygen scavenging activity of and protective activity against cell damage induced by active oxygen. Both Aeseclus hippocastanum L. and Hamamelis virginiana L. are proposed as potent plant extracts with potential application as anti-aging or anti-wrinkle material for the skin.

Animals↗
PubMed1995

Protective activity of hamamelitannin on cell damage induced by superoxide anion radicals in murine dermal fibroblasts.

Previously we demonstrated that hamamelitannin (2',5-di-O-galloyl hamamelose) in Hamamelis virginiana L. exhibits potent superoxide-anion scavenging activity. We then examined the physiological and pharmacological activities of hamamelitannin as well as its functional homologues, gallic acid and syringic acid. The following results were obtained: (1) Hamamelitannin has a higher protective activity against cell damages induced by superoxide anions than gallic acid which is the functional moiety of hamamelitannin. The protective activity of hamamelitannin on murine fibroblast-damage induced by superoxide anions was found at a minimum concentration of 50 microM, while the corresponding figure for gallic acid was 100 microM. (2) Pre-treatment of fibroblasts with hamamelitannin enhances cell survival. (3) The superoxide-anion scavenging activity of the compound in terms of its IC50 value (50% inhibition concentration of superoxide anion radicals generated) was evaluated by ESR spin-trapping. Both hamamelitannin (IC50 = 1.31 +/- 0.06 microM) and gallic acid (IC50 = 1.01 +/- 0.03 microM) exhibited high superoxide-anion scavenging activity followed by syringic acid (IC50 = 13.90 +/- 2.38 microM). (4) When hamamelitannin was treated with superoxide anions generated by a KO2-crown ether system, HPLC analysis showed the disappearance of hamamelitannin and the concomitant formation of hamamelitannin-derived radicals (g = 2.005, delta H1 = 2.16 G, delta H2 = 4.69 G) was detected by ESR spectrometry.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1995

Central GABAergic mechanisms are defective in salt-induced hypertension in borderline hypertensive rats.

We examined the role of central GABAergic mechanisms in salt-induced hypertension and exaggerated responses to stress in borderline hypertensive rats (BHR), the first offspring of spontaneously hypertensive rats (SHR) and Wistar-Kyoto rats (WKY). The studies were done in conscious BHR and WKY on high (H) (8% NaCl) or normal (N) (0.3% NaCl) salt diets for 5 weeks. A high-salt diet elevated arterial pressure (AP) (p < 0.01) and augmented pressor responses to shaker stress (p < 0.05) in BHR but not in WKY. Intravenous hexamethonium caused a greater decrease in AP in BHR-H than in BHR-N at rest. Muscimol (a GABA agonist) injected into the central ventricle (i.c.v.) caused a greater decrease in resting AP (p < 0.01) and heart rate (HR) (p < 0.05) and BHR-H than in BHR-N. Renal sympathetic nerve activity (RSNA) did not change in BHR-H, but increased (p < 0.05) in BHR-N during muscimol-induced hypotension, although the magnitudes of muscimol-induced hypotension were greater in BHR-N than in BHR-N. The increases in RSNA in response to intravenous nitroglycerin were similar in BHR-N and BHR-N. Muscimol attenuated pressor and tachycardic responses to stress more in BHR-N than in BHR-N (p < 0.01). Muscimol did not alter AP and HR at rest or their responses to stress in the two groups of WKY. The magnitudes of pressor response to bicuculline (a GABA antagonist) did not differ between the two groups of BHR. These results suggest that a high salt diet may alter the central GABAergic system in BHR, which contributes to salt-induced hypertension and augmented pressor and tachycardic responses to stress.

Animals↗
PubMed1995

Isolation of Campylobacter spp. from slaughtered cattle and swine on blood-free selective medium.

The charcoal-cefazolin-sodium deoxycholate agar (CCDA) was compared with Butzler agar for selectivity of campylobacters from fecal samples. A total of 279 samples of cecal contents from 176 cattle and 103 pigs slaughtered in Saitama were examined. Fifty-five (31.3%) cattle were found to contain campylobacters by the direct plating culture on CCDA plates, compared with 29 (16.5%) on Butzler agar plates. The positive rates of pig samples on CCDA and Butzler agar were very high, being 96 (93.2%) and 86 (83.5%), respectively. After enrichment culture of 107 cattle specimens in Preston, CEM or Bu 10 broth, the isolation rate on CCDA was also higher (p < 0.01) than that on Butzler agar after enrichment in any medium. These results indicate that CCDA medium is easy to handle without blood and, as to this study shows, is superior to Butzler agar for isolation of Campylobacter species from fecal samples.

Abattoirs↗
PubMed1995

Peroxyl radical scavenging activities of hamamelitannin in chemical and biological systems.

The antioxidative activities of hamamelitannin (2',5-di-O-galloyl-hamamelose), gallic acid and dl-alpha-tocopherol against lipid peroxyl radicals were evaluated in chemical and biological systems. The peroxyl radical scavenging activity was evaluated by electron spin resonance (ESR) method in which both spin-trapping and direct reaction methods were used. In the spin-trapping method, as evaluated by 50% inhibition concentration (IC50) of peroxyl radicals generated in a t-butylhydroperoxide-methemoglobin system, hamamelitannin (IC50 = 95.3 +/- 2.7 microM) showed the highest activity, followed by gallic acid (IC50 = 152.8 +/- 14.6 microM) and dl-alpha-tocopherol (IC50 = 221.5 +/- 4.6 microM) as a positive control. When estimating by the direct method, IC50 values of hamamelitannin, gallic acid and dl-alpha-tocopherol were 93.5 +/- 2.1 microM, 141.6 +/- 2.0 microM and 1590.0 +/- 330.0 microM, respectively. On peroxidation of lipid bilayers induced by 2,2'-azobis-(2-amidinopropane) dihydrochloride (AAPH) in terms of inhibition period (tinh), hamamelitannin showed the longest tinh time (1107.0 +/- 38.18 sec), followed by those of dl-alpha-tocopherol (877.5 +/- 31.8 sec) and gallic acid (771.0 +/- 4.2 sec). The kinetic chain length, defined as the propagation numbers of a lipid peroxyl radical, and calculated from the ratio (Rp/Ri) of the rate of lipid peroxidation to that of inhibition by dl-alpha-tocopherol, hamamelitannin and gallic acid were 27.23, 7.86 and 7.09, respectively. The effects of hamamelitannin, gallic acid and dl-alpha-tocopherol were evaluated on murine fibroblasts exposed to t-butylhydroperoxide (BHP) in terms of the cell survivals. In the protection, hamamelitannin induced the highest survival of 27.6 +/- 0.6% at 50 microM, while both gallic acid and dl-alpha-tocopherol were less active at the same concentrations. On the basis of the results, hamamelitannin was concluded to have a high protective activity on cell damage induced by peroxides.

Animals↗
PubMed1995

[A case of primary mediastinal germ cell tumor, successfully treated with chemotherapy and curative resection].

A 20-year-old man was admitted to our hospital because of an abnormal shadow on chest X-ray Laboratory data revealed a high serum alpha-fetoprotein (AFP) and LDH level. Percutaneous needle biopsy of the tumor suggested primary mediastinal germ cell tumor. Curative resection was performed after three courses of combination chemotherapy (cis-platinum, VP-16, bleomycin and adriamycin). A post-operative histological examination of the mass revealed total necrosis. Post-operative course was uneventful, and he has been free of recurrence for the last six months.

Adult↗
PubMed1995

[Alexia-agraphia of kanji (Japanese morphogram) after left posterior-inferior temporal lesion].

Several cases of selective alexia with agraphia of kanji have been reported in Japan in this decade. It is well known that the lesion in the posterior inferior temporal lobe of the dominant hemisphere is responsible for this cognitive syndrome. Neuropsychological data in our patient suggest that the postero-inferior region of the temporal lobe of the dominant hemisphere may be the visuo-verbal association area for the analysis of the complex visuo-verbal information. The symptoms caused by the same lesion in western patients might be subangular alexia (alexia without agraphia). Alexia with agraphia of kanji and subangular alexia would appear to be distinct entities, but a dual processing hypothesis of visuo-verbal information and the concept of the visuo-verbal association area might well explain both syndromes.

Agraphia↗
PubMed1995

[Clinical study of radiation pneumonitis over 10 years].

We studied clinical aspects of radiation pneumonitis from 1983 to 1992. Fifty seven patients admitted to our hospital because of lung cancer were treated with radiotherapy, and radiation pneumonitis developed in 20 (35.1%). The incidence of radiation pneumonitis was closely related to male sex, chronic obstructive lung disease, and chemotherapy. Pneumonitis was not related to age, or to the area or amount of radiation. Eighteen cases (90%) of pneumonitis occurred during or within one month after radiotherapy. In all but five cases (25%), pneumonitis was limited to the area of radiation. Treatment was mainly with steroids. In 4 cases (20%), pneumonitis recurred when steroid therapy was reduced, and five patients (10%) died.

Aged↗