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Biomedical subjects

Y Sumi

Publications and source records attributed to Y Sumi.

At least 19 recordsLinked to original sources
PubMed2002

Recent advances in the histochemical staining of heavy metals by means of chelating agents, with special reference to cadmium.

This review discusses the way of improving the sensitivity and specificity of chelating agents used for the histochemical demonstration of trace amounts of heavy metals in cells and tissues. In the search for a more sensitive and specific agent, various chelating agents have been prepared and their staining properties for various metals examined. Of those developed 1-(2-benzothiazolylazo)-2-naphthol (BTAN), 2-(8-quinolylazo)-4,5-(diphenyl)imidazole (QAI), and 2-(5-bromo-2-pridylazo)-5-(diethylamino)phenol (BrPADAP) were far superior to conventional staining agents in staining sensitivity. This was particularly so for staining cadmium. When modifying chelating agents to increase staining sensitivity, hydrophobicity of the agent molecules, selection of substituent groups, and the position of the groups added to the agent molecules must be taken into consideration. The most frequently mentioned factors in a staining mechanism are complex-tissue attractive forces, and recent studies have made it clear that weak interactions, such as hydrogen bonds and hydrophobic interactions, contribute significantly. The Hansch pi values were a useful indication of the hydrophobicity of metal staining agents. The published values for stability constants of metal complexes were found to be unreliable guides for choosing a masking agent to block interfering metals. The polyphosphates, aminopolycarboxylic acids, and alkylamines were among the most useful masking agents for metal staining from a practical standpoint.

Animals↗
PubMed2002

Colonization of denture plaque by respiratory pathogens in dependent elderly.

OBJECTIVES: Recently, there has been a resurgence of interest in the interactions between oral conditions and a number of prevalent systemic diseases. The morbidity and mortality of the dependent elderly that result from aspiration pneumonia have been recognized as a major geriatric health problem. The purpose of this study was to gain more information on the microflora of plaque on dentures and to assess the existence of oral infectious pathogens potentially causing the respiratory disease in the dependent elderly. SUBJECTS AND METHODS: The denture bacterial flora of 50 dependent elderly were examined to identify microorganisms by the culture method. RESULTS: 18 species of microorganisms were detected in denture plaque in this study. A variety of pathogens with the potential to cause respiratory infection pathogens colonized on the dentures of dependent elderly. CONCLUSION: The results of the present study revealed that bacteria that commonly cause respiratory infection colonized on the dentures of dependent elderly, suggesting that denture plaque may function as a reservoir of potential respiratory pathogens to facilitate colonization on the oropharynx.

Aged↗
PubMed2001

Involvement of NADH/NADPH oxidase in human platelet ROS production.

Platelets play an important role in atherosclerotic and thromboembolic vascular diseases. It has been reported that reactive oxygen species (ROS) could modify platelet function, and platelets themselves have the ability to produce ROS. However, the enzymatic sources of ROS in platelets have not been fully determined. The NADH/NADPH oxidase system was originally identified as the major source of ROS in phagocytes. Recently, it has become evident that this oxidase is functionally expressed not only in phagocytes but also in various cell types. The present study was undertaken to test the hypothesis that NADH/NADPH oxidase might be expressed in human platelets. Lucigenin-enhanced chemiluminescence (L-CL) and electron spin resonance (ESR) method demonstrated that human platelets obtained from healthy volunteers released ROS, and the released ROS were increased by stimulation with 12-O-tetradecanoylphorbol-13-acetate (TPA) or calcium ionophore. Homogenates of human platelets, as well as MEG01 cells, megakaryocytic cell line, had the enzymatic activity to produce superoxide in NADH/NADPH-dependent manners. This enzymatic activity was suppressed by diphenylene iodonium (DPI), an inhibitor of NADH/NADPH oxidase. Western blot analysis demonstrated that platelets and MEG01 cells expressed p22(phox) and p67(phox) proteins, components of NADH/NADPH oxidase. Thus, human platelets have the enzymatic activity of p22(phox)-based NADH/NADPH oxidase, and this oxidase is likely one of the important sources of ROS in platelets.

Blood Platelets↗
PubMed2001

Two-kaon correlations in central Pb+Pb collisions at 158 a GeV/c.

Two-particle interferometry of positive kaons is studied in Pb+Pb collisions at mean transverse momenta approximately 0.25 and 0.91 GeV/c. A three-dimensional analysis was applied to the lower p(T) data, while a two-dimensional analysis was used for the higher p(T) data. We find that the source-size parameters are consistent with the m(T) scaling curve observed in pion-correlation measurements in the same collisions, and that the duration time of kaon emission is consistent with zero within the experimental sensitivity.

Journal Article↗
PubMed2001

Putaminal hyperperfusion in dystonic posturing on subtracted SPECT: a case report.

Dystonic posturing (DP) is one of the most reliable lateralizing symptoms for mesial temporal lobe epilepsy, although the mechanism remains unclear. We demonstrated a hyperperfusion area in the right putamen on subtracted postictal SPECT by using the automatic registration technique in one patient with ictal DP of the left hand. The putamen may play a key role in DP, similar to other diseases with dystonia.

Adult↗
PubMed2001

The dangers of snowboarding: a 9-year prospective comparison of snowboarding and skiing injuries.

We studied 2,552 snowboarding injuries and 5048 skiing injuries sustained during 1988-97. The number of snowboarding injuries had been increasing year by year and was 6 times as many as skiing injuries (2.0 versus 0.35 per 1,000 visits). The types of snowboarding injuries included fractures (39%), lacerations (21%), dislocations (17%), and contusions (15%). Upper extremity injuries were more frequent than those in the lower extremity in snowboarders. The commonest fractures involved the radius (48%), clavicle (11%), humerus (11%), and ulna (7-8%). The shoulder joint was most commonly dislocated (55%) followed by the elbow (27%), acromioclavicular (10%), finger (4%), and hip joints. In snowboarding accidents, the rates of fractures and dislocations were higher than those in skiing in almost every part of the body. Severe injuries were commoner in snowboarding accidents. We recommend the use of appropriate equipment and instructions for beginners to prevent such injuries.

Adolescent↗
PubMed2001

Spinal injuries in snowboarders: risk of jumping as an integral part of snowboarding.

BACKGROUND: The purpose of this study was to clarify the occurrence rate and characteristics of spinal injuries caused by snowboarding that were sustained at the Okumino skiing area in Gifu Prefecture, Japan, from 1988 to 2000. METHODS: This study was a retrospective review of 13,490 cases of snowboard- or ski-related injury treated at Sumi Memorial Hospital over this period. RESULTS: A total of 7,188 patients sustained snowboard-related injuries, and 238 of these had spinal injuries caused by snowboarding (3.3%), whereas 6,302 patients sustained ski-related injuries, and 86 of these had spinal injuries caused by skiing (1.4%). Although there were no significant differences in the difficulty of slope, location of vertebral fracture, or spinal cord injury between snowboarders and skiers, the incidence of transverse process fractures was significantly higher in snowboard-related than in skiing-related injury (p < 0.05). In addition, there was a significantly higher incidence of spinal injury among beginner snowboarders than among beginner skiers (p = 0.04). Furthermore, intermediate or expert snowboarders were more likely to be injured because of jumping than beginners (p < 0.001), whereas about 70% of spinal injuries caused by skiing resulted from a simple fall. CONCLUSION: Spinal injuries sustained while snowboarding are increasing considerably in incidence and are characterized as complex injuries. We must educate young snowboarders of the risk of this sport, to prevent these serious injuries.

Adolescent↗
PubMed2001

Attitudes to oral care among caregivers in Japanese nursing homes.

OBJECTIVES: The purpose of this study is to investigate oral care practice and awareness of it among caregivers in Japanese nursing homes. METHODS: Caregivers were surveyed by means of a self-administered questionnaire designed to elicit the following information: awareness of oral care, its importance, the burden involved in oral care, and systematization of oral care. RESULTS: The results showed that most caregivers are adequately informed of the importance of oral care, but are inadequately educated in oral care and have little training in systematic oral care. CONCLUSION: The importance of providing appropriate and systematic oral care training must be stressed among caregivers along with the need to develop equipment to simplify and support oral care.

Adult↗
PubMed2001

Expression of glutaredoxin in human coronary arteries: its potential role in antioxidant protection against atherosclerosis.

Oxidative stress is considered an important factor in atherogenesis. Mammalian cells have a complex network of antioxidants such as catalase, superoxide dismutase, and glutathione peroxidase. However, the mechanisms that regulate the cellular redox state in the vessel wall remain unclear. Recent study has shown that thioredoxin, a thiol-disulfide oxidoreductase, is expressed in atherosclerotic plaques of human carotid arteries. In this study, we investigated the localization and expressional change of glutaredoxin and thioredoxin, two important members of the thiol-disulfide oxidoreductases, in autopsy samples of human coronary arteries. In nonatherosclerotic coronary arteries, glutaredoxin was expressed in endothelial cells, in fibroblasts of the adventitia, and most intensely in medial smooth muscle cells. Interestingly, in atherosclerotic lesions such as hypercellular lesions, the infiltrating macrophages highly expressed glutaredoxin. The expressional pattern of thioredoxin was quite similar to that of glutaredoxin. Western blot analysis demonstrated that hydrogen peroxide stimulated the expression of glutaredoxin in a time- and dose-dependent manner in cultured human coronary artery smooth muscle cells. Fluorescence microtopography with dihydroethidium demonstrated that the generation of reactive oxygen species was associated with the expression of glutaredoxin. These results suggest the possible involvement of thiol-disulfide oxidoreductases in antioxidant protection in human coronary arteries.

Aged↗
PubMed2001

[A case of Churg-Strauss syndrome in which positive rheumatoid factor and MPO-ANCA preceded the development of clinical symptoms of vasculitis].

A 52-year-old man in whom bronchial asthma had been diagnosed in 1995 was admitted for the treatment of Churg-Strauss syndrome in June 1997. Positive tests MPO-ANCA and rheumatoid factor preceded the symptoms of vasculitis for several months. A skin biopsy revealed infiltration of eosinophils in the vessel walls, and the diagnosis of Churg-Strauss syndrome was confirmed. After systemic administration of corticosteroids, the symptoms other than mononeuritis improved markedly, and his MPO-ANCA and rheumatoid factor became negative. Rheumatoid factor and MPO-ANCA may be useful for the early diagnosis of Churg-Strauss syndrome in patients with bronchial asthma in which a well-controlled disease develops into an intractable condition.

Antibodies, Antineutrophil Cytoplasmic↗
PubMed2000

Phase-dependent responses of Per1 and Per2 genes to a light-stimulus in the suprachiasmatic nucleus of the rat.

Single brief and discrete light treatments are sufficient to reset the overt mammalian rhythms of nocturnal rodents. In the present study, we examined the phase-dependent response of the mammalian clock genes, Per1 and Per2, to a brief strong light-stimulus (1000 lux) in the circadian oscillator center, the suprachiasmatic nucleus (SCN) of rats. Light-induced elevation of Per1 mRNA was observed through the subjective night (CT16, CT20 and CT0 (=CT24)) with a marked peak at the subjective dawn (CT0). However, the light influence was very limited for the induction of Per2; only weak elevation of Per2 mRNA was detected at CT16. The effect of light-stimulus on the Per1 gene was transient, and the effect was restricted to ventrolateral SCN neurons in both CT0 and CT16 after light exposure. Since it is known that these rats show a light-induced behavioral phase-shift throughout the subjective night with being strongest at subjective dawn, the present results suggest that the transient induction of Per1 in ventrolateral SCN neurons is a critical step in the resetting of the biological clock to environmental light-dark schedule.

Animals↗
PubMed2000

Secretory leukocyte protease inhibitor is a novel inhibitor of fibroblast-mediated collagen gel contraction.

Cultured epithelial cells, including those from the oral epithelium, have been successfully applied in the promotion of scarless wound healing. Factors released from the epithelial cells are thought to contribute significantly to the beneficial effects. In the conditioned medium of human oral epithelial cells, we found a factor that inhibited fibroblast-mediated collagen gel contraction, an in vitro model of wound healing and scar formation. Biochemical analysis identified the factor to be human secretory leukocyte protease inhibitor (SLPI). Fibroblasts transfected with SLPI cDNA showed reduced gel-contracting activity. SLPI purified from the conditioned medium inhibited gel contraction in a dose-dependent manner, and anti-SLPI antibody counteracted this activity. Upon SLPI treatment, human skin fibroblasts in collagen gel became shorter in length and were inhibited in pseudopodia extension. Furthermore, after SLPI treatment, alpha(1)-integrin immunoreactivity decreased, and cyclic AMP levels increased. Excessive gel contraction was observed when fibroblasts treated with TGF-beta1 and fibroblasts from hypertrophic and from keloid scar tissue were cultured in collagen gel. SLPI was also effective in inhibiting gel contraction in the above three models of scar formation. These results suggest that SLPI may be useful in promoting scarless wound healing.

Adolescent↗
PubMed2000

A Cu(II)-mediated C-H oxygenation of sterically hindered tripyridine ligands to form triangular Cu(II)3 complexes.

Two sterically hindered tris-pyridyl methane ligands, tris(6-methyl-2-pyridyl)methane (L1) and bis(6-methyl-2-pyridyl)pyridylmethane (L2), are newly synthesized. Under aerobic conditions, Ln (n = 1 or 2) reacts with CuX2 (X = Cl or Br), oxygenated at the methine position to LnOH or LnOMe. The former alcoholate ligand creates trinuclear Cu(II) complexes [Cu3(X)(LnO)3](PF6)2 [(X, n) = (Br, 1) 1, (C1, 1) 2, (Br, 2) 3, or (C1, 2) 4] in which the alkoxide oxygen atoms bridge copper centers. The crystal structures of 1-4 are presented along with their magnetic susceptibility data. The weak antiferromagnetic coupling between the Cu(II) centers in this trinuclear arrangement is due to weak interaction of the magnetic orbitals (dz2) which are oriented along three alternate sides in a hexagon of the Cu3O3 core in 1-4. Under anaerobic conditions, L1 reacts with CuBr2 to form a square pyramidal complex [CuL1Br2] (9) with the ligand facially capping. [Cu(Br)2(L1OMe)] (10) was obtained after the suspension of 9 in MeOH was stirred under air for 48 h. In the presence of cyclohexene, 9 is converted to [Cu(Br)(L1)]m (m = 1 or 2) 5 quantitatively to give trans- 1,2-dibromocyclohexane, indicating that Br2 is generated during the reaction. The FAB MS spectrum of [18O]-1 prepared by the reaction of L1 with CuBr2 under 18O2 shows that the ligand of [18O]-1 is L1(18O-.) L1(18OH), L1OCD3, and bis(6-methyl-2-pyridyl) ketone were obtained from reaction of L1 with CuBr2 in CD3OD under 18O2. These results indicate that the origins of the O atom in L1OH and L1OMe are O2 and MeOH, respectively. On the basis of these results, a mechanism of the oxygenation of L1 in the present system will be proposed.

Journal Article↗
PubMed2000

Circadian rhythm of serotonin N -acetyltransferase activity in rat lens.

Activity of serotonin N -acetyltransferase (NAT), a key regulatory enzyme in melatonin biosynthesis, was detected in the rat lens. NAT activity in the lens showed significant diurnal variation in vivo and in vitro, peaking during the period of darkness, when the lenses were maintained under 14 hr light/10 hr dark cycle. Cultured lenses exhibited a circadian rhythm of NAT activity when maintained under constant darkness. However, the rhythm in vitro was not entrained when the light/dark cycle was delayed 8 hr from the cycle in intact animals. These data strongly suggest that the rat lens contains a circadian clock that controls NAT activity, although the circadian clock appears to lack a photic entrainment mechanism.

Animals↗