Search PubMed⌕ Search

Biomedical subjects

M Daimon

Publications and source records attributed to M Daimon.

At least 19 recordsLinked to original sources
PubMed2006

High durability cementitious material with mineral admixtures and carbonation curing.

Nuclear waste repositories need highly durable cementitious materials to function for over thousands of years while resisting leaching and degradation. The durability of cementitious material can be effectively improved by reducing permeability and by changing cement hydrates to a less soluble matrix. This paper describes the properties of carbonated new cementitious materials containing belite-rich cement and gamma-2CaO.SiO2 as main components. In addition, the long-term leaching properties are investigated and compared with ordinary Portland cement by using a predictive leaching model.

Carbon↗
PubMed2004

Lateral and medial medullary infarction: a comparative analysis of 214 patients.

BACKGROUND AND PURPOSE: No large-scale study has ever compared the clinical and radiological features of lateral medullary infarction (LMI) and medial medullary infarction (MMI). The aim of this study was to investigate them through the use of cooperatively collected cases. METHODS: Medical information on all patients from 1996 to 2000 with medullary infarction (MI) proven by brain MR images at 35 stroke centers in the Tohoku district, Japan, was collected, and their clinical and radiological features were analyzed. RESULTS: A total of 214 cases of MI were registered. They included 167 cases (78%) of LMI, 41 (19%) of MMI, and 6 (3%) of LMI plus MMI. The mean age of onset and the male-to-female ratio were 60.7 years and 2.7:1 in LMI and 65.0 years and 3.6:1 in MMI, respectively. The middle medulla was most frequently affected in LMI, and the upper medulla was most frequently affected in MMI. Dissection of the vertebral artery was observed in 29% of LMI and 21% of MMI. Prognosis, assessed by the Barthel Index, was favorable in both LMI and MMI. Diabetes mellitus was more frequently associated with MMI than with LMI. CONCLUSIONS: The present study surveyed a large number of MI cases and revealed that (1) the mean age of onset of MMI is higher than that of LMI, (2) the dissection of the vertebral artery is an important cause not only of LMI but also of MMI, and (3) diabetes mellitus is frequently associated with MMI.

Age Factors↗
PubMed2003

[Benefit of off-pump coronary artery bypass grafting evaluated from the change of the regional myocardial oxygen metabolism during bypass grafting].

Recently, off-pump coronary artery bypass grafting (off-pump CABG: OPCAB) has been considered a safe alternative to conventional CABG (CCAB) for myocardial revascularization, because OPCAB improves operative mortality and morbidity from the view of reduction of multi-organ complications, duration of hospital stay, risks of blood transfusion and operative costs. This study was performed to estimate the benefit of OPCAB by examining the change of myocardial oxygen metabolism during OPCAB. Twenty five patients who had undergone OPCAB including the internal thoracic artery (LITA) on the segment 8 of the left anterior descending coronary artery (LAD) were studied in this series, and divided in 2 groups [17 angina pectoris (AP) cases, 8 old myocardial infarction (OMI) cases]. With 3-wave length near infrared spectroscopy (TOS-96: TOSTEC, Tokyo, Japan), the tissue hemoglobin (Hb) volume in the myocardium [Hb index (HbI) = 10 x calibrated absorption at 801 nm/clinical absorption intensity at 801 nm] and the myocardial tissue oxygen saturation (rSo2) on the surface of the left ventricle surrounded by LAD and the 2nd diagonal branch were measured at 5 minutes before and after OPCAB to LAD, and myocardial oxygen metabolism (OM) was calculated [OM = (20-1.34 x systemic Hb x rSo2/100) x HbI]. During OPCAB, several hemodynamic data, systemic Hb and arterial gas findings were not changed. In both groups, the HbI and the OM were significantly increased [HbI: AP group; 1.04 +/- 0.23 to 1.57 +/- 0.41 (p < 0.0001), OMI group; 0.99 +/- 0.28 to 1.55 +/- 0.39 (p = 0.0051), OM: AP group; 11.6 +/- 3.1 to 17.5 +/- 6.0 (p = 0.0010), OMI group; 10.6 +/- 2.3 to 16.1 +/- 2.8 (p = 0.0007)]. The rSo2 was not changed and remained within normal limit during OPCAB. These findings suggested that the regional myocardial oxygen metabolism would be improved immediately just after OPCAB and this finding might be one of the reasons why OPCAB shows the good mortality and morbidity compared with CCAB.

Aged↗
PubMed2002

Optically stimulated luminescence in an imaging plate using BaFi:Eu.

BaFI:Eu phosphors are fabricated using a new method of synthesis: liquid phase synthesis, in which the phosphor particles are formed through the association of Ba2+ ions, F-ions and Eu2+ ions in solution. An intense optically stimulated luminescence (OSL) peak at about 410 nm is observed by stimulating X ray irradiated BaFI:Eu phosphor with about 550-750 nm light. It is found that the peak wavelength of the optically stimulation spectrum is about 690 nm. This result suggests that the semiconductor laser can be used as the stimulating light source. It is also found that the OSL intensity is increased with increasing the X ray dose. The BaFI:Eu phosphor as a photostimulable material for the imaging plate of a computed radiography system provides the following advantages; (1) high X ray absorption coefficient, (2) high monodispersion in size which would contribute to sharp images, (3) high OSL and thus low luminescence mottle and (4) high DQE (detective quantum efficiency).

Barium Compounds↗
PubMed2002

[Influence of preoperative factors on off-pump coronary aortic bypass grafting success].

Heart displacement during off-pump CABG (OPCAB) might induce the hemodynamic instability. We attempted to show which preoperative factors would contribute to an increase in that incident during OPCAB. Between February 2000, and October 2000, 51 patients underwent CABG in Okamura Memorial Hospital. Of these patients, 42 patients (82.4%) underwent OPCAB and 9 patients (17.6%) were operated upon under cardiac arrest with cardiopulmonary bypass (NOPCAB). To expose target coronary arteries for OPCAB, 3 deep pericardial traction stitches were placed near the left lower pulmonary vein (LPV), the left of the inferior vena cava (IVC) and the mid portion between LPV and IVC. To further assist in providing good presentation, patients were placed in Trendelenburg position (30 degree head-down tilt) and the right decubitus (30 degree the right side-down tilt). There were no OPCAB patients to be converted to on-pump CABG during anastomosis. Mean number of grafts in OPCAB group was 2.5 +/- 0.1 per patient, while that in NOPCAB group was 3.4 +/- 0.2 (p < 0.01). The bypass patient rate were 97.1% (100/103) in OPCAB group and 100% (31/31) in NOPCAB group (p = NS). In both groups, bilateral internal thoracic arteries were actively used for reperfusion to the left coronary artery. In the preoperative catheterization findings, pulmonary capillary wedge pressure (PCW) and left ventricular end-diastolic pressure (LVEDP) were significantly higher in NOPCAB group than those in OPCAB group (PCW: 14.0 vs 7.9 mmHg, LVEDP: 14.0 vs 8.7 mmHg: p < 0.05), and there was a tendency of low preoperative ejection fraction (EF) and cardiac index (CI) in NOPCAB group compared with those in OPCAB group, although there were no differences in left ventricular end-diastolic and end-systolic volume index (LVEDVI and LVESVI) between both groups. These findings suggested that PCW and LVEDP within the normal limit could be credited for the success with OPCAB, while an increase of the left ventricular volume would not contribute to the actual success.

Aged↗
PubMed2001

Neonatal-onset hereditary coproporphyria with male pseudohermaphrodism.

The appearance of hereditary coproporphyria (HCP) before puberty is very rare, and all reported cases of early-onset HCP have been in the homozygous or the compound heterozygous state. Some have been identified as harderoporphyria, which is a rare erythropoietic variant form of HCP. These conditions can be differentiated by molecular analysis because the gene abnormality responsible for harderoporphyria seems to be unique (K404E). Early-onset HCP, not harderoporphyria, is reported with a gene mutation in the heterozygous state and male pseudohermaphrodism. It was shown that adrenal gland hypofunction resulted in male pseudohermaphrodism. This case demonstrates the possibility that abnormalities of steroid metabolism influence porphyria.

Adrenal Insufficiency↗
PubMed2001

Candesartan inhibits carotid intimal thickening and ameliorates insulin resistance in balloon-injured diabetic rats.

This study investigates the effects of candesartan, an angiotensin II type 1 receptor blockade, on carotid arterial intimal thickening and glucose tolerance in balloon-injured male Wistar fatty rats and their littermates (Wistar lean rats). Candesartan was orally administered to 12-week-old rats for 21 days, and age-matched rats without the agent were used as the respective controls. Balloon catheterization in the left common carotid artery was performed on day 7, and the artery was removed on day 14 for histological analysis. Compared with the area ratios of the neointima/media in fatty rats without treatment, the ratios in fatty rats treated with candesartan at 1 mg. kg(-1). d(-1) and lean rats without treatment were significantly decreased to 65%; on the other hand, the ratios of fatty rats treated with candesartan at 10 mg. kg(-1). d(-1) and lean rats treated with 1 mg. kg(-1). d(-1) were reduced to 35%, and those of lean rats treated with 10 mg. kg(-1). d(-1) were reduced to 28%. The administration of candesartan also decreased the level of plasma glucose time- and dose-dependently in fatty rats. In an intragastric glucose load, the levels of both glucose and insulin at 30 and 60 minutes were significantly decreased when fatty rats were treated with candesartan at 10 mg. kg(-1). d(-1). In cultured vascular smooth muscle cells from fatty rats, insulin-stimulated Akt (New England Biolabs) phosphorylation and 2-deoxy-D-glucose uptake were inhibited to 59% and 68%, respectively, by angiotensin II, but the effects were ameliorated by the addition of 10(-7) mol/L candesartan. We conclude that candesartan could be effective for the suppression of vascular smooth muscle cell growth dose-dependently in Wistar fatty and lean rats. Furthermore, the agent could improve insulin resistance in Wistar fatty rats.

Angiotensin Receptor Antagonists↗
PubMed2001

Galectin-1 is a component of neurofilamentous lesions in sporadic and familial amyotrophic lateral sclerosis.

In amyotrophic lateral sclerosis (ALS), abnormal accumulation of neurofilaments induces pathological changes such as axonal spheroids, cord-like neurite swellings, and perikaryal conglomerate inclusions in degenerating motor neurons of the spinal cord, and the accumulation seems to cause motor neuron degeneration in this disease. Such ALS lesions were intensely labeled with HepSS-1, a monoclonal antibody to heparan sulfate. Since the identification of HepSS-1-immunoreactive substance seems to be an important step for understanding the molecular pathology of ALS, we purified the substance from human spinal cord tissue to homogeneity. Amino acid sequence of the protein was consistent with that of galectin-1. Immunohistochemistry using antibodies against recombinant human galectin-1 showed that galectin-1 was accumulated in these lesions in ALS. Although HepSS-1 was believed to be specific for heparan sulfate, it reacted with recombinant human galectin-1 which has no heparan sulfate moiety. The results show that galectin-1 is a component of the neurofilamentous lesions in ALS. Since galectin-1 has axonal regeneration-enhancing activity, the abnormal accumulation of galectin-1 to the lesions seems to be related to the pathological process of ALS.

Aged↗
PubMed2001

Physiologic assessment of coronary artery stenosis by coronary flow reserve measurements with transthoracic Doppler echocardiography: comparison with exercise thallium-201 single piston emission computed tomography.

OBJECTIVES: We evaluated the value of coronary flow reserve (CFR), as determined by transthoracic Doppler echocardiography (TTDE), for physiologic assessment of coronary artery stenosis severity, and we compared TTDE measurements with those obtained by exercise thallium-201 (Tl-201) single-photon emission computed tomography (SPECT). BACKGROUND: Coronary flow reserve measurements by TTDE have been reported to be useful for assessing angiographic left anterior descending coronary artery (LAD) stenosis. However, discrepancies exist between angiographic and physiologic estimates of coronary lesion severity. METHODS: We studied 36 patients suspected of having coronary artery disease. The flow velocity in the distal LAD was measured by TTDE both at rest and during intravenous infusion of adenosine. Coronary flow reserve was calculated as the ratio of hyperemic to basal peak (peak CFR) and mean (mean CFR) diastolic flow velocities. The CFR measurements by TTDE were compared with the results of Tl-201-SPECT. RESULTS: Complete TTDE data were acquired for 33 of 36 study patients. Of these 33 patients, Tl-201-SPECT confirmed reversible perfusion defects in the LAD territories in 12 patients (group A). Twenty-one patients had normal perfusion in the LAD territories (group B). Peak CFR and mean CFR (mean value +/- SD) were 1.5 +/- 0.6 and 1.5 +/- 0.7 in group A and 2.8 +/- 0.8 and 2.7 +/- 0.7 in group B, respectively. Both peak and mean CFR < or = 2.0 predicted reversible perfusion defects, with a sensitivity and specificity of 92% and 90%, respectively. CONCLUSIONS: Noninvasive measurement of CFR by TTDE provides data equivalent to those obtained by Tl-201-SPECT for physiologic estimation of the severity of LAD stenosis.

Aged↗
PubMed2001

Characterization of platelet-derived growth factor-induced p38 mitogen-activated protein kinase activation in vascular smooth muscle cells.

BACKGROUND: The mitogen-activated protein (MAP) kinase super-family plays a crucial role in cell growth and differentiation and even in programmed cell death in response to diverse extracellular stimuli. The platelet-derived growth factor (PDGF)-BB is well known to promote the proliferation of vascular smooth muscle cells (VSMC) via extracellular-regulated protein kinases (ERKs), leading to the development of cardiovascular diseases. However, it has not yet been clarified whether PDGFs that include other isoforms can activate the other parallel signal transduction pathways, c-jun NH2-terminal protein kinase (JNK) and p38 MAP kinase (p38), in VSMC. In this study, we investigated the effect of PDGFs on p38 activation in cultured rat VSMC. MATERIALS AND METHODS: After stimulation by PDGFs with SB-203580 or PD-98059, the cells were solubilized, and the expressions of MAP kinases, MAP kinase kinases (MKKs), phosphorylated DNA-binding proteins, and cyclooxigenases (COXs) were examined by immunoblot analysis. RESULTS: PDGFs activated p38 phosphorylation dose-dependently, and the phosphorylations were specifically inhibited by SB-203580 but not by PD-98059. PDGFs also activated the phosphorylation of MKK 3/MKK 6 but not that of either stress-activated protein kinase/ERK kinase or JNK. PDGFs affected the activation of a cyclic AMP response-element binding protein, which was inhibited by SB-203580. However, the activating transcription factor-2 was not activated by PDGFs. Interestingly, the stimulation of PDGFs for 72 h enhanced the level of COX-2, and these levels were decreased by SB-203580. CONCLUSION: These results have clarified that PDGFs activate the p38 cascade via an MKK 3/6 pathway, independently of the ERK cascade, and subsequently regulate the level of COX-2 in rat VSMC, providing that PDGFs influence the inflammatory process in the vascular wall.

Activating Transcription Factor 2↗
PubMed2001

Characterization of an inhibitory effect of pioglitazone on balloon-injured vascular smooth muscle cell growth.

This study investigates whether pioglitazone could suppress an atherogenic process such as balloon-injured carotid intimal thickening and the proliferation of vascular smooth muscle cells (VSMC). We first examined the effect of pioglitazone to determine whether it could suppress intimal thickening induced by balloon catheterization in Sprague-Dawley rats. After 14 days postcatheterization in the left common carotid artery, the neointimal layers were completely occupied by proliferated VSMC, and the area ratio of neointima to media treated with 10 mg/kg/d of pioglitazone was significantly decreased to 57%. Next, we evaluated the effect of pioglitazone on the proliferation of rat cultured VSMC. Piogliotazone dose-dependently decreased the values of DNA synthesis, total cellular protein content, phosphorylations of extracellular signal-regulated protein kinase 1/2 and mitogen-activated protein kinase kinase 1/2, and proliferative cell nuclear antigen in VSMC. Pioglitazone also inhibited the phosphorylation of Pyk2. We conclude that pioglitazone itself could be effective for suppressing the growth of VSMC and consequent carotid intimal thickening.

Animals↗
PubMed2001

Insulin inhibits glucagon-induced glycogenolysis in perivenous hepatocytes specifically.

Hepatocytes form the hepatic acinus as the unit of microcirculation. Following the bloodstream, at least 2 different zones can be discerned: the periportal and perivenous zones. Two types of hepatocytes, periportal hepatocytes (PPHs) and perivenous hepatocytes (PVHs), have been thought to be functionally heterogeneous, with PPHs being predominantly gluconeogenic and PVHs being glycolytic. We therefore investigated the region-specific functional effects of insulin on glycogen synthesis, glycolysis, glycogenolysis, and gluconeogenesis in isolated PPHs and PVHs prepared by using the digitonin-collagenase method. Glycogen synthesis from 5 to 20 mmol/L glucose did not differ between the PPHs and PVHs of fed rats during 60 minutes of incubation. Lactate release induced by 5 to 20 mmol/L glucose was 3 times greater from PVHs than from PPHs (P <.01). The addition of insulin did not accelerate either glycogen synthesis or lactate release during 60 minutes of incubation. Insulin did not inhibit glucose release from gluconeogenic substrates with or without 0.2 nmol/L glucagon in either the PPHs or the PVHs of fasting rats. Insulin antagonized the 0.1 nmol/L glucagon-induced increase in glucose release from the PVHs of fed rats during 30 minutes of incubation (to 56.1% +/- 7.2%, P <.01) but not that from the PPHs (to 81.8% +/- 7.3%, P =.10). Thus the antagonizing effect was greater in PVHs than in PPHs (P <.01). Insulin binding did not differ between the PPHs and PVHs of fed rats. It was confirmed that PVHs are actually glycolytic. An acute metabolic effect of insulin was observed only in antagonizing glucagon-induced glycogenolysis in PVHs specifically. The specific effect of insulin on PVHs might depend on the differences in intracellular characteristics between PPHs and PVHs rather than hormone binding.

Animals↗
PubMed2001

Platelet-derived growth factor BB-induced p38 mitogen-activated protein kinase activation causes cell growth, but not apoptosis, in vascular smooth muscle cells.

The aim of this experiment was to examine the regulation of p38 mitogen-activated protein (MAP) kinase by platelet-derived growth factor (PDGF)-BB and its biological effects on rat cultured vascular smooth muscle cells (VSMCs). VSMCs were obtained from aortae of male Wistar rats by the media explant technique. After being stimulated by PDGF-BB with or without the p38 MAP kinase-specific inhibitor, SB-203580, the cells were solubilized, and the levels of phosphorylated p38 MAP kinase were examined by immunoblot analysis. The amounts of DNA synthesis and content were measured by using [3H]-thymidine and Hoechst-33258 dye, respectively. The detection of apoptotic cells was evaluated by the TUNEL method. PDGF-BB could phosphorylate p38 MAP kinase dose-dependently, and the phosphorylation was specifically inhibited by SB-203580 in a dose-dependent manner. However, PDGF-BB did not affect the protein level of p38 MAP kinase. Both [3H]-thymidine incorporation and total cellular DNA content were increased by PDGF-BB, and these elevations were prevented by SB-203580. In contrast, PDGF-BB-stimulated VSMCs did not show apoptotic change in spite of the presence or absence of SB-203580. These results established that PDGF-BB activated p38 MAP kinase and subsequently regulated cell growth in VSMCs, providing a molecular mechanism by which p38 MAP kinase can cause the development of cardiovascular diseases, including atherosclerosis.

Animals↗
PubMed2001

Genotype Arg/Arg, but not Trp/Arg, of the Trp64Arg polymorphism of the beta(3)-adrenergic receptor is associated with type 2 diabetes and obesity in a large Japanese sample.

OBJECTIVE: Despite a large number of studies, no association of the Trp64Arg polymorphism of the beta(3)-adrenergic receptor gene with obesity and type 2 diabetes has yet to be clearly elucidated. We examined the associations in a large population-based sample. RESEARCH DESIGN AND METHODS: A total of 1,685 subjects (935 women and 750 men, aged 58.7 +/- 12.4 years) from a cohort population (n = 3,706) of the Funagata Diabetes Study were divided into three groups according to genotypes: Trp/Trp (n = 1,155), Trp/Arg (n = 486), and Arg/Arg (n = 44). Glucose tolerance was diagnosed according to the 1985 World Health Organization criteria. Subjects who had a BMI > or =30 kg/m(2) were considered obese. Associations with the traits related to obesity, diabetes, hypertension, and dyslipidemia were also examined. The chi(2) test and analysis of variance were used for the association studies and to assess the differences in the traits' values, respectively. RESULTS: More subjects with genotype Arg/Arg were obese and had diabetes (13.6% for each) than those with genotype Trp/Trp (3.29%, P < 0.001; and 4.16%, P = 0.007, respectively) or genotype Trp/Arg (2.06%, P < 0.001; and 5.97%, P = 0.051, respectively). No significant differences in the frequencies of occurrence of these conditions were observed between genotypes Trp/Arg and Trp/Trp. Traits related to obesity, such as percent body fat (28.82 +/- 7.95 vs. 25.93 +/- 7.21, P = 0.038) and BMI (25.07 +/- 3.84 vs. 23.63 +/- 3.18, P = 0.018), were higher in the genotype Arg/Arg than in the genotype Trp/Trp groups. CONCLUSIONS: Genotype Arg/Arg, but not Trp/Arg, of the beta(3)-adrenergic receptor was associated with both obesity and type 2 diabetes in a large Japanese sample.

Aged↗