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Biomedical subjects

Y Akutsu

Publications and source records attributed to Y Akutsu.

At least 37 records · Page 2Linked to original sources
PubMed1997

Correlations between resting regional wall motion and regional myocardial blood flow (at rest and during exercise) in infarct-related myocardium--a study with [13N]ammonia positron emission tomography.

We evaluated quantitatively the correlations between resting wall motion and regional myocardial blood flow (RMBF; at rest and during exercise) in infarct-related myocardium. The study was performed in 28 subjects: 21 patients who had previously suffered myocardial infarction of the anteroseptal wall, and 7 normal individuals. Positron emission tomography (PET) with [13N]ammonia was performed at rest and during low-grade exercise (bicycle ergometer fixed at 25 W for 6.5 min), and RMBF was measured quantitatively from the radioactivity in myocardial tissue and arterial blood. Resting regional wall motion was calculated using the centerline method on left ventriculographic findings. Resting regional wall motion was correlated with RMBF both at rest and during exercise in the infarct areas (anterior walls; y = 2.74 +/- 4.25 x 10(-2)x, r = 0.43, at rest; and y = -2.48 + 3.04 x 10(-2)x, r = 0.48, during exercise, p < 0.05; septal walls; y = -3.61 + 5.64 x 10(-2)x, r = 0.62, at rest; and y = -3.46 + 4.31 x 10(-2)x, r = 0.62, during exercise, p < 0.01). In each infarct-related wall, the coefficient (the slope) during exercise was smaller than that at rest (3.04 vs 4.25 and 4.31 vs 5.64 in each), and the infarct areas with preserved wall motion showed higher RMBF during exercise than those with reduced wall motion. Our results may show that wall motion depends on viable but ischemic myocardium in infarct-related walls.

Adult↗
PubMed1997

Significance of downsloping ST-segment depression induced by low-level exercise in severe coronary artery disease. Assessment with myocardial ischemia and collateral perfusion.

Exercise-induced downsloping ST-segment depression is a common manifestation of severe myocardial ischemia. Although greater downsloping ST-segment depression is suspected to indicate more severe ischemia, its exact relationship to regional myocardial blood flow (RMBF) has not yet been clarified. We investigated the relationship between the magnitude of downsloping ST-segment depression and exercise-induced changes in RMBF and collateral perfusion. Nitrogen-13 ammonia positron emission tomography was performed in 6 healthy volunteers and 72 patients with angiographically proven coronary artery disease. The left ventricle was divided into 11 regions of interest, and RMBF in each region was measured at rest and during low-level supine bicycle exercise. Downsloping ST-segment depression of 0.1 mV or more at 80 milliseconds after the J point was accepted as significant. Low-level exercise induced downsloping depression of 0.1 to 0.2 mV in 10 patients (group D1) and downsloping depression of 0.2 mV or more in 8 patients (group D2). Multivessel disease was common in both group D1 (80% of patients) and group D2 (88% of patients). Collateral circulation was significantly more frequent in group D1 (90%) than in group D2 (13%, p < 0.01). Ischemic areas were larger and cardiac function was worse in group D2 than in group D1. The RMBF increased sufficiently in all regions (56 +/- 30%) with exercise in the healthy group. In group D1, RMBF was unchanged or decreased in ischemic areas (10 +/- 23%) but increased sufficiently in surrounding areas (50 +/- 32%). In group D2, RMBF was unchanged in ischemic areas (17 +/- 24%) and increased insufficiently in surrounding areas (41 +/- 21%). Therefore, exercise-induced downsloping ST-segment depression of 0.1 to 0.2 mV may reflect an underlying change in blood flow in viable myocardium with collateral perfusion, and downsloping depression of 0.2 mV or more may reflect more severely impaired myocardium without collateral perfusion.

Adult↗
PubMed1997

Radical formation from the reaction of combustion smoke with diphenylamine.

We have attempted to examine the effects of radical scavengers, such as amines and phenols, to trap gas-phase radicals produced from the combustion of Poly (methyl methacrylate)(PMMA), which might cause damage to a living body, using an electron spin resonance (ESR) spin-trapping technique. As a result, diphenylamine did not decrease the amount of radicals but rather increased it. It indicates that under the conditions of this study, gas-phase radicals were hardly trapped by radical scavengers and that the precursors to produce other kinds of radicals can exist. It was suggested that from the experiments using several peroxides, the precursors should be diacylperoxides produced from the combustion of PMMA.

Butylated Hydroxytoluene↗
PubMed1995

Functional role of coronary collaterals with exercise in infarct-related myocardium.

We evaluated the regional myocardial blood flow in collateral dependent infarct-related areas to examine the functional role of coronary collaterals. Regional myocardial blood flow was measured by positron emission tomography with 13N-ammonia at rest and during low-grade exercise (bicycle ergometer fixed at 25 W for 6.5 min). The study was performed in 24 subjects, consisting of 19 patients with prior myocardial infarction, and five normal individuals. Regional myocardial blood flow was calculated using the radioactivity in myocardial tissue measured by positron emission tomography and the radioactivity in arterial blood. Concerning the infarct related area, the exercise caused myocardial blood flow to decrease by 18.4% (P < 0.01) in the collateral-dependent areas (n = 8) of angiographically positive collaterals, and to increase by 14.4% (P = not significant) in the areas (n = 10) of negative collaterals. Four patients in whom the myocardial blood flow in all walls, including the normal areas, decreased with exercise were excluded from this evaluation. Myocardial blood flow in collateral-dependent infarct-related areas appeared to decrease transiently by low-grade exercise. Our results suggest that collaterals increase the incidence of exercise-induced ischemia, but may protect the infarct related but viable myocardium from necrosis.

Adult↗
PubMed1995

Interleukin-6 in cerebrospinal fluid of patients with central nervous system infections.

Interleukin(IL)-6 levels were measured in cerebrospinal fluid (CSF) and serum samples from pediatric patients with central nervous system (CNS) infections by means of an enzyme-linked immunosorbent assay. Mean IL-6 concentrations in CSF samples from patients with bacterial meningitis (49,017 +/- 44,730 pg/ml) were significantly higher than those in patients with aseptic meningitis (1076 +/- 1572 pg/ml) or encephalitis (409 +/- 835 pg/ml). In aseptic meningitis and encephalitis, IL-6 levels in serum were within the lower ranges (< 100 pg/ml), in contrast with the highly elevated levels found in bacterial meningitis (14,332 +/- 18,385 pg/ml). In 5 of the 15 patients with encephalitis, elevated levels of IL-6 were observed in the initial CSF samples despite normal findings of routine CSF examinations. Also, sequential CSF samples revealed that there was an increase in the CSF cell count in two of the five patients. These results validated the potential of measuring IL-6 in CSF samples for the purpose of providing additional information on routine laboratory test results.

Blood-Brain Barrier↗
PubMed1995

Relation between cardiac index and regional myocardial blood flow in the non-infarcted wall using PET with 13NH3 in healed myocardial infarction.

It is not clear whether there is any relationship between cardiac output and myocardial blood flow in the infarcted heart. We measured regional myocardial blood flow (RMBF) quantitatively by positron emission tomography (PET) with 13N-ammonia at rest in 18 patients with prior myocardial infarction. RMBF was calculated using the radioactivity in myocardial tissue measured by PET and the radioactivity of arterial blood. Cardiac output was determined by the dilution method using 13NH3 as an indicator, and the relation between cardiac output and RMBF was evaluated at the same time during PET study. There was a good linear correlation between cardiac index (C.I.) and mean RMBF in non-infarcted myocardium (r = 0.45, p < 0.05), and non-infarcted size (r = 0.74, p < 0.01). There was an even better linear correlation between C.I. and sigma RMBF (representing the product of mean RMBF and non-infarcted size) as follows: y = 0.016x + 1.94, r = 0.76 (p < 0.001). It was indicated that the value of C.I. may be related to RMBF of non-infarcted myocardium and its size.

Aged↗
PubMed1995

[A case of Kasabach-Merrit syndrome complicated with DIC treated effectively by long term oral administration of warfarin].

A 20 year-old female patient with Kasabach-Merrit syndrome, suffered from chronic consumption coagulopathy due to localized intravascular coagulation in the tumors. She had been diagnosed as Kasabach-Merrit syndrome immediately after birth and below knee amputation of her right lower leg was performed at the age of 2 years because of her giant hemangioma on the right foot and lower leg. After the operation, she had often complained of severe pain and enlargement of the residual tumors due to continuous thrombus formation within the tumors. She was admitted to the third Department of Tohoku University Hospital in order to initiate oral anticoagulant therapy with Warfarin at the age of 12 years. After the administration of 2.5 mg/day Warfarin, she has maintained good clinical condition until now, despite the occasional occurrence of coagulation abnormalities. We believe that the results of this case indicate the efficacy of oral anticoagulant therapy in the treatment of chronic consumption coagulopathies complicated with other diseases.

Administration, Oral↗
PubMed1994

Determination of regional myocardial blood flow with 13N-ammonia positron emission tomography during low-grade exercise for evaluating coronary artery stenosis.

We measured regional myocardial blood flow (RMBF) by positron emission tomography (PET) with 13N-ammonia at rest and during low-grade exercise using a bicycle ergometer fixed at 25 watts for 6.5 min. The ischemic area with severe coronary artery stenosis was evaluated in terms of quantitative RMBF. The study was performed in 46 subjects consisting of 19 patients with old myocardial infarction, 20 with effort angina pectoris, and 7 normal individuals. RMBF was calculated using the radioactivity in myocardial tissue measured by PET and the radioactivity in arterial blood. The PET data were compared with coronary arteriographic findings and ECG findings. When the analysis was restricted to the anterior wall of the myocardium, it was found that exercise caused RMBF to increase by 44.9% (n = 28) in normal area, to increase by 23.3% (n = 37) in severely stenotic area (stenosis > or = 90%), and to decrease by 17.4% (n = 20) in infarcted area. When we considered only the infarcted area of the entire heart, exercise caused RMBF to decrease by 26.6% (n = 30) in the area of angiographically positive collaterals, and to increase by 0.8% (n = 31) in the area of negative collaterals. Thus, we were able to quantitate the degree of ischemia in myocardium that was associated with severe coronary artery stenosis. By application of low-grade exercise, RMBF in normal myocardium increased, while RMBF in myocardium perfused by collaterals decreased.

Adult↗
PubMed1994

[Study of correlation between urinary IL-6 level and mesangial lesion in childhood onset IgA nephropathy].

In the present study, urinary IL-6 levels in 28 patients with IgA nephropathy (IgAN), 10 patients with idiopathic minimal change nephrotic syndrome (IMCNS) and 11 normal controls were measured using by an ELISA method to clarify the role of IL-6 as an autocrine growth factor of mesangial cells. Spot urine was centrifuged at 1000 rpm for 10 minutes at 4 degrees C and the supernatant was utilized as samples. The patients with IgAN were classified into three groups, group I (18 patients); minor glomerular abnormalities, group II (5 patients); focal segmental lesions, group III (5 patients); diffuse glomerulonephritis, according to the WHO classification of glomerular diseases. Geometric mean +/- S.E. of urinary IL-6 was 1.619 +/- 0.075 in patients with IgAN (group I; 1.432 +/- 0.078, group II; 1.920 +/- 0.181 and group III; 1.987 +/- 0.055), 0.681 +/- 0.174 in IMCNS and 0.506 +/- 0.181 in normal controls, respectively. Urinary IL-6 levels were significantly elevated in patients with IgAN than in IMCNS and normal controls, but did not necessarily reflect the severity of mesangial lesions. Some patients with prominent segmental mesangial proliferation in group II showed much higher urinary IL-6 levels than those in group III. Elevated urinary IL-6 levels in group II may be involved in higher activity of mesangial proliferation, and the decreased production of IL-6 observed in some patients of group III may related to advanced glomerular sclerosis. The results suggests that IL-6 plays an important role as a mesangial proliferative growth factor in IgAN and that measurement of urinary IL-6 levels by an ELISA method is a useful method to estimate the degree of mesangial proliferation and disease activities easily and noninvasively in patients with IgAN.

Adolescent↗
PubMed1993

[Monostotic fibrous dysplasia of the occipital bone].

A case of monostotic fibrous dysplasia of the occipital bone in a 18-year-old female is described. She was admitted to our hospital with a hard, painless mass (5 x 5 cm) in the occipital region. Neurological examination and laboratory data revealed no abnormalities. Skull x-rays showed a radiolucent lesion with a sclerotic margin in the occipital bone. CT scan revealed an intradiploic multilocular mass separated by bone trabeculae. RI bone scan showed an abnormal uptake in this lesion. T1 and T2 MR image showed an abnormal low-intensity lesion in the occipital region. Operation was performed to verify the nature of the lesion, which was histologically confirmed to be an inactive fibrous dysplasia. Postoperative course was uneventful. Although its occurrence in the occipital bone is uncommon, fibrous dysplasia should be considered in the differential diagnosis of skull tumors.

Adolescent↗
PubMed1992

Immunochemical characterization of a cytochrome P450 isozyme and a protein purified from liver microsomes of male guinea pigs and their roles in the oxidative metabolism of delta 9-tetrahydrocannabinol by guinea pig liver microsomes.

A protein (designated as protein-B) was purified from liver microsomes of adult male guinea pigs by an affinity chromatography with omega-aminooctyl Sepharose 4B, followed by HPLC using DEAE-5PW and hydroxyapatite columns which had been used to purify a cytochrome P450 (P450) isozyme (P450-A) from the same subcellular fraction (Narimatsu et al., Biochem Biophys Res Commun 172: 607-613, 1990). Protein-B had a molecular mass of 49 kDa in SDS-PAGE, but did not show absorbance at 417 nm for heme. Further, it did not show any oxidative activities towards aniline (AN), d-benzphetamine (d-BP), p-nitroanisole (p-NA) or delta 9-tetrahydrocannabinol (delta 9-THC) in a reconstituted system including dilauroylphosphatidylcholine, NADPH-P450 reductase, and cytochrome b5. However, antiserum against protein-B raised in rabbits suppressed liver microsomal oxidative activities towards d-BP and p-NA dose-dependently. The antibody decreased delta 9-THC oxidative activity most effectively, but did not decrease AN hydroxylation activity. Antiserum against P450-A suppressed all the activities towards these four substrates, especially towards delta 9-THC, in liver microsomes of male guinea pigs. Moreover, reconstitution with hemin made it possible for protein-B to produce some oxidative activity toward delta 9-THC. These results suggest that protein-B is also a cytochrome P450 isozyme which has lost a heme moiety during purification steps. Both P450-A and protein-B could have a role as cytochrome P450 isozymes in the oxidative metabolism of drugs, especially that of delta 9-THC by the liver microsomes of adult male guinea pigs.

Amino Acid Sequence↗
PubMed1992

Vitreous, retinal and subretinal hemorrhages associated with von Willebrand's syndrome.

Two patients with von Willebrand's syndrome had intraocular hemorrhages without trauma or neovascularization. A 13-year-old Japanese girl complained of sudden spotted vision in her left eye. Vitreous, peripapillary retinal, and subretinal hemorrhages were seen by ophthalmoscopy in the affected eye. In addition, a 19-year-old Japanese man had repeated vitreous hemorrhage and epistaxis. Also noted was gyrate atrophy of the choroid and retina. Analysis of the coagulation-fibrinolysis system revealed decreased activities of Factor VIII and von Willebrand's factor in both patients. The amount of von Willebrand's factor antigen also was decreased. These results suggested that the patients had von Willebrand's syndrome. The bleeding tendency in the disorder appeared to be responsible for the pathogenesis of the intraocular hemorrhages seen in these patients.

Adolescent↗
PubMed1992

Pseudomembranous bronchitis (non-diphtherial) resulting in sudden death: an autopsy report.

A 69-year-old woman was admitted because of dyspnea. Thereafter, she fell into a state of shock. Resuscitation was attempted but she did not respond to it and died on the second hospital day. According to the autopsy findings, a wide range of area from the larynx to the trachea was covered with pseudomembrane. In the culture of bacteria, alpha Streptococcus and Corynebacterium genus (non-diphtherial) were all that was detected. These findings suggest that pseudomembranous lesion, an endogenous foreign matter of the air passage should be suspected when a patient presents with sudden dyspnea.

Aged↗
PubMed1991

Localization of acidic and basic fibroblast growth factor mRNA in human brain tumors.

Acidic and basic fibroblast growth factors (aFGF and bFGF) are closely related peptide mitogens acting on both mesoderm- and neuroectoderm-derived cells, including fibroblasts, endothelial cells and glial cells. In order to identify the expression of mRNAs for these growth factors, in situ hybridization using human aFGF and bFGF RNA probes was performed in 24 human brain tumors. The mRNAs for aFGF and bFGF were expressed in the cells of various tumors (1/1 and 1/1 astrocytoma, 2/2 and 2/2 anaplastic astrocytomas, 6/6 and 6/6 glioblastomas, 4/4 and 4/4 meningiomas, 3/3 and 3/3 schwannomas, 1/2 and 1/2 pituitary adenomas, 4/4 and 4/4 metastatic carcinomas, 0/1 an 0/1 hemangioblastoma, 0/1 and 0/1 craniopharyngioma) and were also detected in endothelial cells and surrounding neuronal cells of brain tumors. These results suggest the possibilities that aFGF and bFGF contribute to the uncontrolled growth of tumor cells and the proliferation of endothelial cells in autocrine and paracrine manners, and that the expression of mRNAs for these growth factors in the surrounding neuronal cells results in enhancement of tumor growth.

Adolescent↗
PubMed1991

Urinary excretion of terminal complement complexes in glomerular disease.

To evaluate renal terminal complement activation in patients with glomerular diseases, we measured terminal complement complexes (TCCs) in plasma and urine with sandwich enzyme-linked immunosorbent assay (ELISA) using a monoclonal antibody against a C9 neoepitope expressed on TCC and a polyclonal antihuman C7 antibody. TCCs were detectable in plasma but not in urine in most of normal controls. In plasma, TCC levels were elevated in 4 of 22 patients with lupus nephritis and in 6 of 12 with membranoproliferative glomerulonephritis. However all patients with IgA nephritis, focal glomerulosclerosis, idiopathic membranous nephritis and idiopathic minimal change nephrotic syndrome (MC) showed normal values. In urine, TCCs were detectable in almost all patients with heavy proteinuria (greater than or equal to 100 mg/ml) except MC. The TCCs present in urine were partially purified by gel filtration using Sepharose 6B and were found to contain C5, C6, C7, C8, C9 and S protein by ELISA. Although the molecular weight of TCC is similar to that of IgM, the fractional excretion rate of TCC was about 100 times higher than that of IgM. These results suggest that TCCs detectable in urine contain SC5b-9 complexes and are mostly of renal origin.

Adolescent↗