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Biomedical subjects

M Hashimoto

Publications and source records attributed to M Hashimoto.

At least 181 records · Page 10Linked to original sources
PubMed2000

Comparison of standard coronary artery bypass grafting and minimary invasive direct coronary artery bypass grafting. Early and mid-term result.

OBJECTIVES: We studied indications and problems involved in minimally invasive coronary artery bypass grafting (MIDCAB). METHODS: We compared patients profiles, graft patency, stenosis severity, morbidity, mortality, long-term survival and freedom from cardiac accidents in 174 patients undergoing elective standard coronary artery bypass grafting (CABG) and 128 undergoing between January 1996 and March 1999. RESULTS: No statistically difference was seen in gender, diabetes mellitus, renal failure, cerebrovascular accident, multi-vessel disease ratios, or left main trunk stenosis between 2 groups. Internal thoracic artery graft patency was 97% (114/118) and the rate of anastomotic stenosis (> 50%) was 9% (10/118) compared to 96% (213/221) in the MIDCAB group. The 3-year survival rate was 91% in the MIDCAB group and 92% in the CABG group and freedom from cardiac accidents, most involving pericutaneus transluminal coronary angioplasty retreatment, was 66% in the MIDCAB group and 88% in the CABG group. CONCLUSION: Although patency and stenosis incidence did not differ between 2 groups, freedom from cardiac accidents was lower in the MIDCAB group.

Aged↗
PubMed2000

C-terminal alpha-synuclein immunoreactivity in structures other than Lewy bodies in neurodegenerative disorders.

alpha-Synuclein is a presynaptic terminal protein that accumulates abnormally in plaques in Alzheimer's disease (AD), in Lewy bodies in Lewy body disease (LBD) and in filamentous inclusions in multiple system atrophy. Since it has been previously shown that proteinase K or formic acid pretreatment enhances alpha-synuclein immunoreactivity in Lewy bodies and plaques, we hypothesized that the immunoreactivity in tangles, glial cells and Pick bodies might be revealed by such pretreatment. Brain sections from patients with AD, LBD, progressive supranuclear palsy (PSP), corticobasal degeneration (CBD) and Pick's disease were pretreated with proteinase K or formic acid and immunostained with antibodies against the N-terminal, C-terminal or non-amyloid beta component of AD amyloid (NAC) regions of alpha-synuclein. This study showed that after proteinase K (but not formic acid) pretreatment the anti-C terminus antibody immunostained neurofibrillary tangles of AD, PSP and CBD, and glial inclusions of PSP and CBD, as well as Pick bodies. Western blot analysis confirmed that in cases other than LBD, the anti-C terminus antibodies also recognized the native alpha-synuclein band and no cross-reactive bands were observed. In contrast, in LBD, after formic acid pretreatment with the anti-NAC antibody astroglial cells and granular neurons were immunostained. The N-terminal region antibody only recognized the lesions in LBD cases and not those of other neurodegenerative disorders. These results support the view that different fragments of alpha-synuclein might play an important role in the pathogenesis of several neurodegenerative disorders.

Aged↗
PubMed2000

Osteoblastoma-like osteosarcoma.

We report an osteoblastoma-like osteosarcoma in the right proximal fibula in a 22-year-old woman. Radiographs showed an irregular osteolytic lesion from the metaphysis to the epiphysis in the proximal fibula with partial destruction of cortical bone. Tissue from a biopsy indicated a typical osteoblastoma. Curettage and bone graft was performed. One year after the surgery, local recurrence occurred, and a wide excision was performed. Histological examination of the en-bloc surgical specimen revealed the tumor had permeated through the host bony trabeculae, although the nuclear atypia was not marked. Immunohistochemical expression of MIB-1 was detected in 9.0% of cells.

Adult↗
PubMed2000

Normal-tension glaucoma with reversed ophthalmic artery flow.

PURPOSE: To describe a case of normal-tension glaucoma with bilateral complete occlusion of the internal carotid artery. METHODS: A 58-year-old man who had a 2-year history of normal-tension glaucoma in the left eye presented with ocular ischemic syndrome. To evaluate the orbital circulation, cerebral angiography and color Doppler imaging were performed. RESULTS: Cerebral angiography showed bilateral complete occlusion of the internal carotid artery and collateral blood supply through the right and left ophthalmic arteries, in which the flow was reversed. Moreover, color Doppler imaging revealed lower blood flow velocities in the left central retinal and short posterior ciliary arteries, suggesting a steal phenomenon. CONCLUSION: Normal-tension glaucoma in the present case may be caused by chronic reduction of retrobulbar blood flow resulting from a steal phenomenon.

Blood Flow Velocity↗
PubMed2000

Isolation and localization of type IIb Na/Pi cotransporter in the developing rat lung.

Differential display analysis of rat lung at different developmental stages identified a fragment, HG80, which appeared on embryonic day 16.5 and thereafter. A full-length cDNA derived from a cDNA library of newborn rat lung probed with HG80 was the rat counterpart of sodium-dependent phosphate transporter type IIb and was designated rNaPi IIb. In situ hybridization showed that rNaPi IIb was expressed in type II alveolar cells, suggesting a role in the synthesis of surfactant in the alveoli. The time-dependent changes in localization of this gene in the developing lung and its possible use as a type II pneumocyte marker are discussed.

Animals↗
PubMed2000

alpha-synuclein promotes mitochondrial deficit and oxidative stress.

Abnormal accumulation of the presynaptic protein alpha-synuclein has recently been implicated in the pathogenesis of Alzheimer's and Parkinson's diseases. Because neurodegeneration in these conditions might be associated with mitochondrial dysfunction and oxidative stress, the effects of alpha-synuclein were investigated in a hypothalamic neuronal cell line (GT1-7). alpha-Synuclein overexpression in these cells resulted in formation of alpha-synuclein-immunopositive inclusion-like structures and mitochondrial alterations accompanied by increased levels of free radicals and decreased secretion of gonadotropin-releasing hormone. These alterations were ameliorated by pretreatment with anti-oxidants such as vitamin E. Taken together these results suggest that abnormal accumulation of alpha-synuclein could lead to mitochondrial alterations that may result in oxidative stress and, eventually, cell death.

Animals↗
PubMed2000

Limit of warm ischemia time before cryopreservation in rat tracheal isografts.

BACKGROUND: The viability of cadaveric tracheal grafts undergoing cryopreservation is still unclear. We evaluated the limit of warm ischemia time before cryopreservation in rat tracheal isografts. METHODS: Each isograft was harvested from donor rats 0 to 48 hours (0, 6, 12, 18, 24, and 48 hours) after circulatory arrest, immersed in the preservative solution, and stored in a deep freezer until reaching -80 degrees C and then was kept in liquid nitrogen for 3 months. Heterotopic transplantation into the omentum was performed after the isografts were thawed. Graft morphology 3 months after transplantation was assessed. RESULTS: The stepwise increase of warm ischemia time significantly reduced graft survival. A prolonged period of warm ischemia had a degenerative effect on both the epithelium and cartilage. The morphology of the epithelium and cartilage in isografts undergoing warm ischemia for less than 18 hours was better preserved, whereas it deteriorated in isografts undergoing warm ischemia for more than 24 hours. CONCLUSIONS: We thus conclude that the permissible period of warm ischemia before 3-month cryopreservation to maintain tracheal isograft viability is 18 hours in rats.

Animals↗
PubMed2000

Heart preservation in HTK solution: role of coronary vasculature in recovery of cardiac function.

BACKGROUND: Poor myocardial tolerance to prolonged cold ischemia remains a major concern in heart transplantation. In this study, we estimated superiority of Histidine-Tryptophan-Ketoglutarate (HTK) over University of Wisconsin (UW) as a cardiac preservation solution. METHODS: Isolated rat hearts were mounted on a Langendorff apparatus to estimate the baseline cardiac function. The hearts were arrested and stored at 4 degrees C in UW and HTK solution for 8 hours, and then reperfused. The aortic flow, coronary flow, cardiac output, rate pressure product, and left ventricular dp/dt in the HTK group recovered significantly more than the UW group. The values of myocardial total adenine nucleotides and the adenosine triphosphate to adenosine diphosphate ratio were higher in the HTK than in the UW group. We also examined coronary vascular responsiveness using left coronary arteries dissected from the rat hearts before flushing, before storage, after storage, and after reperfusion. RESULTS: The maximal relaxation response to acetylcholine was significantly higher in the HTK than in the UW group after reperfusion, although there were no significant differences at each stage before reperfusion. In addition, the endothelium-independent relaxation response to sodium nitroprusside in the HTK group was also well preserved after reperfusion. CONCLUSIONS: These results indicate that HTK is superior to UW solution for cardiac preservation. HTK protects coronary vasculature during preservation, which together with reperfusion might lead to improved functional cardiac recovery following preservation.

Adenosine↗
PubMed2000

Influence of sex and age on serum nitrite/nitrate concentration in healthy subjects.

Measurement of serum nitrite/nitrate (NOx) concentrations has been considered useful to estimate nitric oxide production in humans. However little is known about the physiologic range and the factors affecting serum NOx levels. The aim of this study was, thus, to investigate the influence of sex and age on serum NOx levels in healthy subjects. We selected 263 healthy subjects (118 women and 145 men, 20-69 y) from 505 consecutive subjects who received annual medical checkups at our hospital. Serum NOx levels were determined using an analyzer employing the Griess method. The linear regression analysis showed that NOx increased significantly according to age in women (r=0.22, P<0.05), but did not in men (P=NS). Women of the younger age group (<40 y) showed significantly lower NOx levels than men of the same age group (P<0.05), whereas there was no significant difference between men and women of the older age (> or =40 y). Then, to investigate whether menopause affects serum NOx levels, middle aged women (46-55 y) were selected. Multiple logistic regression analysis showed that menopause was an independent factor for increased serum NOx levels in middle aged women (r=0.4, P<0.05). These results suggest that the serum NOx concentration is affected by age in healthy women, possibly depending on menopausal state.

Age Factors↗
PubMed2000

Shear stress enhances prostacyclin release from endocardial endothelial cells.

The effect of shear stress on the release of prostacyclin (PGI2) from cultured endocardial endothelial cells (EECs) was investigated. EECs were harvested from the right ventricle (RV) and the left ventricle (LV) of porcine heart. Confluent EECs were incubated under various degrees of shear stress (0.2, 1, 4 and 6 dyne/cm2) and PGI2 release from each cell was measured. PGI2 release from LV-EECs and RV-EECs was enhanced by the elevation of shear stress in a shear-dependent manner with a rapid increase at the onset of flow; however, there was no significant difference in PGI2 production between RV-EECs and LV-EECs. production of PGI2 was significantly inhibited from cells exposed to 8-(dimetilamino) octyl 3,4,5-trymethoxybenzoate hydrochloride (10 and 100 microM: an inhibitor of intracellular calcium mobilization) or cyclopiazonic acid (10 microM: an endoplasmic reticulum Ca2+-ATPase inhibitor). These results indicate that shear stress enhances PGI2 release from cultured EECs and that mechanotransduction of shear stress depends on calcium mobilization in EECs.

Animals↗
PubMed2000

The effect of hybrid layer thickness on bond strength: demineralized dentin zone of the hybrid layer.

OBJECTIVES: The purpose of this study was to evaluate the correlation between hybrid layer thickness and bond strength using specimens acid-conditioned for varying lengths of time. METHODS: The dentin surfaces of human premolars, sectioned to remove the enamel from the labial surface, were conditioned with 35.0% phosphoric acid of an adhesive resin system (Scotchbond Multi-Purpose; 3M) for 15 (as directed by the manufacturer), 60, 120, or 180 s (experimental acid-conditioning times). The bonded specimens were then sectioned perpendicular to the adhesive interface to measure the hybrid layer thickness by SEM. The specimens for the micro-tensile test were sectioned perpendicular to the adhesive interface and trimmed to an hourglass-shape. Then, the micro-tensile test was performed at a crosshead speed of 1.0 mm/min. The bond strengths and hybrid layer thickness were statistically compared with Student's t-test (p < 0.05). All fractured surfaces were also observed by SEM. RESULTS: Significant differences between the groups exposed to acid for 15 and 60 s, and those exposed for 120 and 180 s were observed in hybrid layer thickness and bond strength (p < 0.05). SEM observation of the fractured surfaces revealed that a demineralized dentin zone without resin impregnation remained within the hybrid layer. SIGNIFICANCE: A demineralized dentin zone was formed in the bond structures after prolonged acid-conditioning, resulting in low bond strength. The shrinkage of the hybrid layer due to desiccation during the SEM examination process provided evidence of the presence of the demineralized dentin zone within the hybrid layer.

Acid Etching, Dental↗
PubMed2000

Postoperative vesicourethral function after ultrasonic surgical aspirator-assisted surgery of gynecologic malignancies.

OBJECTIVE: The most concerned complication of radical hysterectomy includes the vesicourethral dysfunction. The use of Cavitron ultrasonic surgical aspirator (CUSA) may preserve the blood supply to the urinary tract even during the surgical procedure, prompting us to evaluate the advantage of using the CUSA with the complication. STUDY DESIGN: We analyzed medical profiles of a total of 275 patients with pelvic lymphnode dissection (137 subjects with radical hysterectomy and 138 with modified radical hysterectomy). RESULTS: The use of CUSA in radical (formal or extended) hysterectomy reduced the period for the residual urine to become <50 ml in cases of advanced stages equal and over Ib of uterine cervical cancers. CONCLUSION: The CUSA may be more effective in the prevention of radical hysterectomy for its major complication, vesicourethral dysfunction. The CUSA-assisted surgery may be applicable, primarily, for advanced uterine cancer.

Female↗
PubMed2000

A new approach for glomerular lesions: evaluation of scanning acoustic microscopy (SAM) for experimental glomerular disease in rats.

Most pathological evaluations using ordinary optical microscopy are usually qualitative and subjective. The beneficial properties of scanning acoustic microscopy (SAM) include not only observation of microstructure but also quantitative measurement of acoustic propagation speed, indicating the tissue elasticity. In this study, we examined the capability of SAM to evaluate pathological findings in glomeruli using anti-Thy.1 glomerulonephritis. Light microscopic observations of the glomeruli showed severe cell proliferation and mesangial matrix expansion at 10 days after induction of glomerulonephritis and, yet, to a lower extent at day 21 with onset of healing. C-mode scanning of SAM enabled imaging of glomerular structure compatible to findings of ordinary light microscopy. In addition, glomerular propagation speed in nephritic rats was significantly increased at day 10, and then decreased at day 21. These results indicate that SAM evaluation may be a new, useful technique for quantitative evaluation of proliferative glomerular lesions.

Animals↗
PubMed2000

Phospholipase A2-mediated superoxide production of murine peritoneal macrophages induced by chrysotile stimulation.

In the present study, we investigated how chrysotile-stimulated macrophages generate superoxide using murine peritoneal macrophages, with special attention to the modulatory role of phospholipase A(2) (PLA(2)). We examined the effects of the following inhibitors and antagonists for signaling molecules on the superoxide anion (O(2)(-)) production of chrysotile-stimulated macrophages: p-bromophenacyl bromide (pBPB) and mepacrine for PLA(2); islet-activating protein (IAP) for G-protein; H-7 for protein kinase C (PKC); AA861 for 5-lipoxygenase (5-LO); indomethacin for cyclo-oxygenase (COX); ETYA for both 5-LO and COX; hexanolamine PAF for platelet-activating factor (PAF). The PLA(2) and PKC inhibitors effectively inhibited the chrysotile-induced superoxide anion production of macrophages, but not the G-protein inhibitor, the 5-LO and COX inhibitors, and the PAF antagonist. We also examined the effects of the PLA(2) inhibitors on macrophages stimulated by phorbol 12-myristate 13-acetate (PMA) which directly activates PKC. The two structurally different PLA(2) inhibitors showed differential effects on the PMA-induced superoxide generation: pBPB inhibited it but mepacrine did not. These results suggested that (1) PLA(2) and PKC modulate the chrysotile-induced O(2) production, and (2) two different kinds of PLA(2) work upstream and downstream of PKC, but (3) G-protein, 5-LO and COX metabolites, and PAF have no modulatory role in the reaction.

Animals↗
PubMed2000

Site-directed mutagenesis of Asp280 suggests substrate-assisted catalysis of chitinase A1 from Bacillus circulans WL-12.

To study the involvement of Asp280 of chitinase A1 from Bacillus circulans WL-12 in the catalytic reaction of the enzyme, site-directed mutagenesis of this residue was carried out. Kinetic analysis of the mutant chitinases revealed that the residue is not absolutely essential for the catalytic reaction and thus, does not act as the catalytic nucleophile.

Journal Article↗