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T Yamaguchi

Publications and source records attributed to T Yamaguchi.

At least 145 records · Page 8Linked to original sources
PubMed2001

Tear in the trabecular meshwork caused by an airsoft gun.

PURPOSE: To report a case of a tear in the trabecular meshwork caused by an airsoft gun, a toy that propels a plastic bullet. METHODS: Case report. RESULTS: A 7-year-old Japanese boy sustained an ocular injury to the right eye from an airsoft gun. Ophthalmic examination 1 hour after the injury showed a best-corrected visual acuity in the injured eye of hand motion, corneal abrasion and edema, hyphema, and commotio retinae. Gonioscopy 6 days after the injury revealed a tear in the trabecular meshwork as well as an angle recession. Ultrasound biomicroscopy (UBM) strongly suggested that the tear extended into Schlemm's canal. Corneal abrasion and edema, hyphema, and commotio retinae resolved over 10 days, and best-corrected visual acuity improved to 20/15. Two months after the injury, the trabecular meshwork had not healed. CONCLUSION: Airsoft guns can cause a full-thickness tear in the trabecular meshwork, which may contribute to development of late-onset glaucoma. UBM is useful to evaluate the tomographic features of the disrupted trabecular meshwork. The potential force of airsoft guns to cause substantial ocular injuries should be recognized. Wearing ocular protection should be mandatory while playing with airsoft guns.

Child↗
PubMed2001

Surgical outcome of pulmonary resection in chronic necrotizing pulmonary aspergillosis.

BACKGROUND: Surgical treatment of chronic necrotizing pulmonary aspergillosis is hazardous and controversial. METHODS: Ten patients (8 men, 2 women; mean age, 50 years) with chronic necrotizing pulmonary aspergillosis underwent pulmonary resection between 1989 and 2000. Single segmentectomy or lobectomy, pneumonectomy, or bilobectomy and multisegmentectomy were performed. Clinicopathologic features of these patients were reviewed to clarify the role of surgical intervention for chronic necrotizing pulmonary aspergillosis. RESULTS: The mean time from the onset of clinical symptoms to operation was 5.3 years. Surgical intervention was undertaken because of prolonged illness in 4 patients and hemoptysis in 6 patients. All patients survived. Three major complications (1 late empyema, 2 bronchopleural fistulas) occurred in the large dead space in the right pleural cavity. All survivors were free of aspergillosis at a mean follow-up time of 4.8 years, and only 1 patient required antifungal drugs for relapse during the follow-up period. CONCLUSIONS: Aggressive pulmonary resection in chronic necrotizing pulmonary aspergillosis should be considered when patients have prolonged illness or frequent hemoptysis. Empyema and bronchopleural fistula are the main complications. Concomitant thoracoplasty or intrathoracic transposition of the chest wall musculature is recommended in cases involving a large residual pleural cavity on the right side.

Adult↗
PubMed2001

The application of dimethyldioxirane for the selective oxidation of polyfunctional steroids.

Oxidation and epoxidation reactions of a series of structurally different steroids related to methyl 5 beta-cholanoates having hydroxyl groups and/or double bonds by treatment with dimethyldioxirane (DMDO) are described. Steroidal alcohols, olefines, and unsaturated alcohols and conjugated enones with DMDO were transformed into ketones, epoxides, and epoxy-ketones, respectively, in good isolated yields. The regio- and stereoselectivities for DMDO reaction differing from those observed for organic peracids, tert-butyl hydroperoxide and alkaline hydrogen peroxide are also discussed.

Epoxy Compounds↗
PubMed2001

Microbial-ecological significance of sulfide precipitation within anaerobic granular sludge revealed by micro-electrodes study.

Micro-electrodes were applied to anaerobic granular sludge, which was developed in a UASB reactor, to examine intra-granule profiles with respect to pH, glucose and sulfide. When glucose was employed as a bulk liquid substrate, the micro-electrodes study demonstrated the pH behavior along granule depth: pH decrement at the granule exterior portion due to acid formation (buildup of acidity), and subsequent pH increment at the granule inner portion due to the consumption of acid (buildup of alkalinity). Sulfide micro-electrode proved sulfate reduction that mostly occurred at the granule exterior portion. Chemical equilibrium consideration evidently explained the occurrence of ferric sulfide predominantly in the interior portion, which accounts well for the morphology of a representative double-layered structure of granules grown on a low level of sulfite. Inorganic elements distribution within anaerobic granule was examined by electron probe X-ray micro analysis (EPMA) and ICP methods. The presence of crystalline calcium carbonate (calcite) was identified by X-ray diffraction analysis.

Bacteria, Anaerobic↗
PubMed2001

beta-amyloid deposits in transgenic mice expressing human beta-amyloid precursor protein have the same characteristics as those in Alzheimer's disease.

A transgenic mouse expressing the human beta-amyloid precursor protein with the "Swedish" mutation, Tg2576, was used to investigate the mechanism of amyloid-beta peptide (Abeta) deposition. We characterized Abeta deposits in the cerebral cortex biochemically and pathologically. A surface-enhanced laser desorption/ionization affinity mass spectrometric study using the 6E10 monoclonal antibody demonstrated that the major species of Abeta in a formic acid-extracted fraction of the cortex were Abeta(1-38), Abeta(1-40) and Abeta(1-42). Immunohistochemistry using antibodies to the carboxy-terminal epitopes of Abeta(1-40) and Abeta(1-42), as well as 6E10, showed that plaques containing Abeta(1-42) were more numerous than those containing Abeta(1-40) throughout the cortex. Laser confocal analysis of the immunoreactivities in the plaques demonstrated that Abeta(1-40) was preferentially located in the central part of the Abeta(1-42) positive plaques. Enzyme-linked immunosorbent assay measurements of Abeta(1-40) and Abeta(1-42) showed that Abeta(1-40) was several-fold more abundant than Abeta(1-42). From these data we suggest that Abeta(1-42) deposition may precede Abeta(1-40) deposition, while Abeta(1-40) begins to deposit in the central part of the plaques and accumulates there. Furthermore, localization of Abeta(1-40) corresponded almost exactly to congophilic structures, which were associated with aberrant swollen synapses detected with antibodies to synaptophysin and alpha-synuclein. Thus, Abeta deposits in Tg2576 mice have similar characteristics to those in Alzheimer's disease.

Alzheimer Disease↗
PubMed2001

Involvement of the brain-derived neurotrophic factor/TrkB pathway in neuroprotecive effect of cyclosporin A in forebrain ischemia.

Recent studies have shown that cyclosporin A, a specific antagonist of calcineurin, a phosphatase, ameliorates neuronal cell death in the CA1 sector of the hippocampus after forebrain ischemia in animal models. The mechanism of this neuroprotective effect, however, has not yet been established. Brain-derived neurotrophic factor (BDNF), a member of the neurotrophins, is one of the potent survival and developmental factors whose expression is regulated by cyclic AMP-response element-binding protein (CREB). Activation of CREB is dependent on its phosphorylation at Ser(133), and calcineurin has been reported to dephosphorylate CREB via protein phosphatase 1. Based on these observations, we attempted to investigate how cyclosporin A treatment would affect the changes of phosphorylated CREB (pCREB), BDNF and its receptor tyrosine kinase B (TrkB) after forebrain ischemia in rats. Phosphorylation of CREB was kept augmented throughout the time course examined in cyclosporin A-treated animals, while it ceased without cyclosporin A. Reverse transcription-polymerase chain reaction revealed prolonged maintenance of BDNF mRNA expression in the CA1 sector of cyclosporin A-treated animals. The protein expression of BDNF and TrkB appeared to be up-regulated in cyclosporin A-treated animals, whereas it was transiently up-regulated but decreased to the marginal level of expression without cyclosporin A.From these results we suggest that cyclosporin A induces pCREB by an inhibition of calcineurin, resulting in the induction of BDNF. The mechanisms by which cyclosporin A protects the CA1 region from neuronal cell death in forebrain ischemia may involve the interaction of pCREB, BDNF and TrkB.

Animals↗
PubMed2001

Assessment of noninvasive markers in identifying patients at risk in the Brugada syndrome: insight into risk stratification.

OBJECTIVES: The aim of this study was to compare the use of various noninvasive markers for detecting risk of life-threatening arrhythmic events in patients with Brugada syndrome. BACKGROUND: The role of conduction disturbance in arrhythmogenesis of the syndrome is controversial, whereas it is well established that repolarization abnormalities are responsible for arrhythmias. The value of noninvasive markers reflecting conduction or repolarization abnormalities in identifying patients at risk for significant arrhythmias has not been shown. METHODS: We assessed late potentials (LP) using signal-averaged electrocardiography (ECG), microvolt T-wave alternans (TWA), and corrected QT-interval dispersion (QTD) in 44 consecutive patients who had ECGs showing a pattern of right bundle branch block and ST-segment elevation in leads V1 to V3 but structurally normal hearts. The patients were compared with 30 normal individuals. RESULTS: Eleven patients were excluded from data analysis because of an absence of ECG manifestations of Brugada syndrome at the time of the tests. A history of life-threatening events defined as syncope and aborted sudden death was present in 19 of 33 patients (58%); in 15 of the 19 patients, stimulation induced ventricular fibrillation or polymorphic ventricular tachycardia. The LP were present in 24 of 33 patients (73%); TWA were present in 5 of 31 patients (16%); and a QTD >50 ms was present in 9 of 33 patients (27%). The incidence of LP in Brugada patients was significantly (p < 0.0001) higher than in the controls, whereas incidences of TWA and QTD were not significantly different. Multivariate logistic regression analysis revealed that the presence of LP had the most significant correlation to the occurrence of life-threatening events (p = 0.006). CONCLUSIONS: Late potentials are a noninvasive risk stratifier in patients with Brugada syndrome. These results may support the idea that conduction disturbance per se is arrhythmogenic.

Action Potentials↗
PubMed2001

U73122 inhibits the dephosphorylation and translocation of cofilin in activated macrophage-like U937 cells.

Cofilin, an actin-binding protein, plays an important role in the migration, phagocytosis, and superoxide production of activated phagocytes through cytoskeletal reorganization. In unstimulated phagocytes, cofilin is a major phosphoprotein. However, upon activation, the phosphoprotein is dephosphorylated and translocated from cytosol to plasma membranes. Only the unphosphorylated form of cofilin is an active form that binds actin, whereas the regulatory mechanisms of cofilin have not been elucidated. We found that 1-[6-[[17beta-3-methoxyestra-1,3,5(10)-trien-17-yl]amino]hexyl]-1H-pyrrole-2,5-dione (U73122), an inhibitor of phospholipase C (PLC), suppressed both opsonized zymosan (OZ)-induced dephosphorylation and translocation of cofilin in macrophage-like U937 cells at 4 microM concentration. OZ triggered an increase in inositol 1,4,5-trisphosphate (IP3), and U73122 inhibited it. 1-[6-[[17beta-3-Methoxyestra-1,3,5(10)-trien-17-yl]amino]hexyl]-1H-pyrrole-2,5-pyrrodione-dione (U73343), which was employed as an inactive analogue, had no such inhibitory activities as did U73122. Furthermore, herbimycin A, an inhibitor of src-type tyrosine kinase, also inhibited OZ-triggered IP3 formation. These results suggest that the activity and localization of cofilin are regulated by PLC at the downstream of src-family tyrosine kinase.

Actin Depolymerizing Factors↗
PubMed2001

Characterization of itch-associated responses of NC mice with mite-induced chronic dermatitis.

To clarify the behavioral and pathological features of spontaneous scratching of NC mice with mite-induced chronic dermatitis, we investigated the spontaneous and pruritogen-evoked scratching of NC mice. Although the frequency of scratching of NC mouse did not increase under specific pathogen-free environment, it gradually and markedly increased from 3 to 6 weeks after transfer to conventional environment. The onset of increase in spontaneous scratching was similar to that of dermatitis development and the elevation of plasma concentration of immunoglobulin E. At chronic stage (16 weeks after environment change), the frequency of spontaneous scratching was roughly parallel to the degree of dermatitis, but not to the plasma concentration of immunoglobulin E. The spontaneous scratching of NC mice with dermatitis was inhibited by distraction and the opioid antagonist naltrexone, suggesting that the scratching is itch-associated response. An intradermal injection of serotonin, but not histamine and substance P, elicited scratching of the injected site. Methysergide and cyproheptadine inhibited the serotonin-induced scratching but not spontaneous scratching. The results suggest that marked elevation of plasma immunoglobulin E is not always the cause of spontaneous itch-associated response of NC mice with dermatitis. Serotonin, histamine and substance P may not play an important role in spontaneous itch-scratch response at a chronic stage.

Animals↗
PubMed2001

A case of awareness with sevoflurane and epidural anesthesia in ovarian tumorectomy.

We experienced a case of awareness during ovarian tumorectomy in a patient who was anesthetized with sevoflurane and epidural anesthesia. A 74-year-old woman was scheduled for resection of an ovarian tumor. After epidural catheter insertion, anesthesia was induced with 60 mg of propofol and 6 mg of vecuronium, and anesthesia was maintained with epidural anesthesia (1% mepivacaine), 1 to 2% sevoflurane, and 66% nitrous oxide in oxygen. The operative course was uneventful and the total operation time was 2 hours and 50 minutes. Two days after the operation, we were surprised to learn that the patient complained of awareness during the surgery.

Aged↗
PubMed2001

Clinical application of vacuum-assisted cardiopulmonary bypass with a pressure relief valve.

OBJECTIVES: Hemodilution induced by cardiopulmonary bypass (CPB) often prevents open heart operations without blood transfusion because of a large CPB-priming volume. A vacuum-assisted venous drainage system appears to overcome this problem and our previous experimental study demonstrated the beneficial effect of a vacuum-assisted CPB with a pressure relief valve. In this study, we clinically applied this novel system, and evaluated its efficacy by comparing it with the results of a conventional siphon-dependent drainage system. METHODS: Sixty patients undergoing open heart operation were divided into Group V (vacuum-assisted system, n=30) and Group S (siphon-dependent system, n=30). The vacuum-assisted system contains a powerful vacuum generator and a pressure relief valve to keep the negative pressure in the reservoir constant when the blood suction is used. RESULTS: The CPB-priming volume was significantly smaller in Group V (V vs. S: 1071+/-88 vs. 1405+/-137 ml; P<0.01), resulting in the lower hemodilution in Group V evidenced by the minimum hemoglobin level (V vs. S: 6.83+/-1.06 vs. 5.78+/-0.79 mg/dl; P<0.01) and blood transfusion rate (V vs. S: 9 vs. 20%; P<0.01). There were no significant differences in the plasma free hemoglobin level and the reduction ratio of plasma haptoglobin between the groups. CONCLUSIONS: These data demonstrate that this vacuum-assisted CPB can provide simplification of the CPB circuit, resulting in a smaller CPB-priming volume and lower hemodilution. This vacuum-assisted CPB may attenuate the negative effect of CPB by minimizing hemodilution and appears to be a useful modification to accomplish no blood-requiring open heart operations.

Blood Transfusion↗
PubMed2001

Effects of estradiol, progesterone and testosterone on the function of carp, Cyprinus carpio, phagocytes in vitro.

The modulation of phagocytic cells by beta-estradiol, 11-ketotestosterone and progesterone was analyzed in common carp Cyprinus carpio. Carp kidney leukocytes were cultured in RPMI 1640 medium containing 0.1, 1, 10, 100 or 1000 nM concentration of each hormone. The production of superoxide anion, nitric oxide (NO) and phagocytosis were measured in vitro. Similar concentrations of cortisol were used as control. Phagocytic activities of carp macrophages was suppressed by treatment with beta-estradiol, progesterone and 11-ketotestosterone. The production of NO in carp macrophages was suppressed by progesterone and 11-ketotestosterone. However, carp macrophages incubated with beta-estradiol, progesterone and 11-ketotestosterone did not show any difference in the production of superoxide anion in comparison with control macrophages in the absence of hormones. Carp macrophages treated with cortisol suppressed phagocytosis and the production of nitric oxide and superoxide anion.

Animals↗
PubMed2001

Vam3p structure reveals conserved and divergent properties of syntaxins.

Syntaxins and Sec1/munc18 proteins are central to intracellular membrane fusion. All syntaxins comprise a variable N-terminal region, a conserved SNARE motif that is critical for SNARE complex formation, and a transmembrane region. The N-terminal region of neuronal syntaxin 1A contains a three-helix domain that folds back onto the SNARE motif forming a 'closed' conformation; this conformation is required for munc18-1 binding. We have examined the generality of the structural properties of syntaxins by NMR analysis of Vam3p, a yeast syntaxin essential for vacuolar fusion. Surprisingly, Vam3p also has an N-terminal three-helical domain despite lacking apparent sequence homology with syntaxin 1A in this region. However, Vam3p does not form a closed conformation and its N-terminal domain is not required for binding to the Sec1/munc18 protein Vps33p, suggesting that critical distinctions exist in the mechanisms used by syntaxins to govern different types of membrane fusion.

Amino Acid Sequence↗
PubMed2001

Association of polymorphic alleles of the calcium-sensing receptor gene with the clinical severity of primary hyperparathyroidism.

OBJECTIVE: Primary hyperparathyroidism (pHPT) is a heterogeneous disease in its clinical course and severity. Previous studies have suggested an association between the clinical severity of pHPT and the genotypes of vitamin D receptor, oestrogen receptors and PTH molecules. The Ca-sensing receptor (CaR) is activated by an extracellular calcium ion and controls PTH secretion, and thus polymorphisms of CaR might be associated with the magnitude of PTH secretion and the clinical severity of pHPT. In this study, we examined the relationship between CaR polymorphisms and biochemical markers in pHPT patients. METHODS: We analysed 105 Japanese pHPT patients (85 females and 20 males; mean age 55.6 +/- 14.0 years). We determined the CaR genotypes of G990R and intron 5 polymorphisms with genomic DNA extracted from peripheral lymphocytes. The intron 5 polymorphism was defined as T/T, T/C and C/C. RESULTS: In the G990R polymorphism, serum levels of both intact PTH and alkaline phosphatase (ALP) were significantly higher and the serum level of phosphorus was significantly lower in the RR group than in the GG group. In the intron 5 polymorphism, the T/T group showed significantly lower serum levels of intact PTH and Ca. Furthermore, patients with both the codon 990 RR and the intron 5 C allele (the RRC(+) group) had significantly higher serum levels of intact PTH and ALP than did the other patients. CONCLUSIONS: The present study is the first to show that CaR polymorphisms of G990R and intron 5 were closely associated with the magnitude of PTH secretion and/or PTH degradation as well as the clinical severity in pHPT patients.

Adolescent↗
PubMed2001

Plasma leptin concentrations are associated with bone mineral density and the presence of vertebral fractures in postmenopausal women.

OBJECTIVE: Although total fat body mass (FM) is considered to be one of the major determinants of bone mass, the mechanism by which FM and bone mass are positively correlated remains unclear. Leptin, the product of the obese (ob) gene, is secreted from adipocytes and its plasma levels are known to be positively correlated with %fat (FM divided by total body weight). There is recent evidence suggesting that leptin directly stimulates osteoblastic differentiation. Thus it is possible that the anabolic action of this hormone on bone may participate in the positive correlation between FM and bone mass. In this study, we analysed the relationships between either plasma leptin levels or %fat vs. bone mineral density (BMD) values as well as the presence of vertebral compression fractures, and evaluated whether or not plasma leptin levels were associated with BMD or bone fragility in a manner independent of FM. PATIENTS: One hundred and thirty-nine postmenopausal women (age 48-78 years, mean 62.5), who visited our outpatient clinic for the evaluation of osteoporosis. DESIGN AND MEASUREMENTS: Plasma concentrations of leptin after an overnight fast were measured by radioimmunoassay. BMD values were measured by dual-energy X-ray absorptiometry (DXA) at the lumbar spine, femoral neck and whole body. Distal one-third of radius BMD was measured by single photon absorptiometry (SPA). Vertebral fractures were assessed by lateral thoracic and lumbar spine radiographs. RESULTS: Although neither plasma leptin levels nor %fat correlated with age, there was a significant positive correlation between plasma leptin levels and %fat (r = 0.563, P < 0.001). Plasma leptin levels were significantly and positively correlated with BMD values at all skeleton sites measured, and multiple regression analysis revealed that this positive relationship was still observed with BMD values of the femoral neck and of the whole body, even after %fat and age were taken into account. Moreover, plasma leptin levels but not %fat were significantly lower in women with vertebral fractures than in those without fractures. When multiple logistic regression analysis was performed with either plasma leptin value or %fat employed as independent variables, plasma leptin values but not %fat were selected as an index affecting the presence of vertebral fractures. CONCLUSION: Our study showed that plasma leptin levels but not %fat are associated with BMD and the presence of vertebral fractures in postmenopausal women, suggesting that circulating leptin might play a physiological role in maintaining bone mass as well as better bone quality.

Adipose Tissue↗
PubMed2001

Effects of glibenclamide on hydroxyl radical formation in the postischaemic reperfused heart with or without inhalation anaesthetics.

BACKGROUND AND OBJECTIVE: We investigated whether glibenclamide (glyburide) affects myocardial metabolism and hydroxyl radical formation in the rat heart-lung preparation with or without inhalation anaesthetics. METHODS: Thirty-seven male Wistar rats were allocated to four groups: (a) control group (C), received vehicle only; (b) group G, received glibenclamide 10 microM L-1; (c) group I, received glibenclamide 10 microM L-1 and 1.4% isoflurane during perfusion; (d) group S, received glibenclamide 10 microM L-1 and 2.7% sevoflurane during perfusion. Glibenclamide was administered 7 min after the start of perfusion. Ten minutes later, the heart was rendered globally ischaemic for 10 min by reducing the preload and afterload to zero, and then the heart was reperfused for 10 min. The formation of hydroxyl radicals in perfusate blood and heart was measured with high performance liquid chromatography using salicylic acid. Hydroxyl radicals react with salicylic acid, yielding dihydroxybenzoic acids. RESULTS: The recovery time from ischaemia in group G was significantly longer than the other groups. However, there were no differences in myocardial metabolites and dihydroxybenzoic acids concentrations in the perfusate and heart among the four groups. CONCLUSIONS: Glibenclamide prolonged recovery time from ischaemia, but did not affect hydroxyl radical formation in the postischaemic reperfused heart. In addition, isoflurane and sevoflurane shortened this time. These facts suggest that mechanisms other than effects of volatile anaesthetics on hydroxyl radical formation are responsible for their protective effects in this model.

Adenosine Triphosphate↗
PubMed2001

Comparison of phosphocreatine concentration in the human masseter and medial pterygoid muscles by 31P-CSI.

The aim of this study is to compare phosphocreatine (PCr) concentrations of human masseter and medial pterygoid muscles by a recently developed localized magnetic resonance spectroscopy (MRS) method, chemical shift imaging (CSI). The characteristic spectra of phosphorous metabolites including PCr and beta-ATP from the superficial part of the masseter (SM) and the deep part of the masseter (DM) and the medial pterygoid muscles (MPt) from 11 volunteers, 20-27-year-old were obtained. The study clearly demonstrated higher PCr/beta-ATP in the SM and MPt than in the DM both in mean values (P < 0.01) and in individual subjects. The results indicate that SM and MPt are power producers. There were no significant differences in the mean values of the PCr/beta-ATP ratios in SM and MPt, however, the PCr/beta-ATP ratios varied individually and the subjects could be divided into three distinct groups: values of MPt higher than SM (group A, 4 subjects); values of MPt almost equal to SM (group B, 3 subjects); and values of MPt lower than SM (group C, 4 subjects). There appears to be a close relationship between the PCr content as determined in the groups here and occlusal guidance.

Adenosine Triphosphate↗