Search PubMed⌕ Search

Biomedical subjects

M Nakazawa

Publications and source records attributed to M Nakazawa.

At least 109 records · Page 6Linked to original sources
PubMed1999

Ultrastructural features of the myocardium of children with dilated cardiomyopathy.

We analyzed the electron-microscopic features of endomyocardial biopsy from pediatric patients with dilated cardiomyopathy (DCM). The specimens examined were taken from the right ventricle of ten patients aged from 2 to 15 years (mean 9.7 years). Biopsy specimens from eight patients with congenital heart disease (tetralogy of Fallot), aged from 3 to 12 (mean 7.3 years), and ten adult patients with DCM, aged from 32 to 60 (mean 45 years), were also examined. Patients considered to have endocardial fibroelastosis, arrhythmogenic right ventricular cardiomyopathy, specific cardiomyopathy, or coronary heart disease were excluded from this study. Specimens from pediatric patients with DCM showed various degrees of ultrastructural abnormalities of myocytes, including myofibrillar fragmentation, mitochondrial abnormalities, and intracellular edema. The ultrastructurally determined contractility failure index based on the severity of myocardial degeneration at the electronmicroscopic level was 4.9 +/- 1.1. This value was significantly higher than that in patients with tetralogy of Fallot (0.9 +/- 0.6, P < 0.001) but was not significantly different from that in adult patients with DCM (6.1 +/- 2.6). The index of pediatric patients with DCM who died within 3 years was high (6.0 +/- 0.8). Basal lamina layering of a capillary (BLL) in the myocardium was revealed in 1 of the 10 (10%) pediatric patients with DCM and in 6 of the 10 (60%) adult patients with DCM (P < 0.05). No BLL was noted in the patients with tetralogy of Fallot. These findings may be related to the pathogenesis of DCM in children and adults.

Adolescent↗
PubMed1999

Indocyanine green iris angiography of lung carcinoma metastatic to the iris.

BACKGROUND: To investigate the usefulness of indocyanine green (ICG) iris angiography for monitoring vascular abnormalities and the clinical course of metastatic iris tumor during chemotherapy. METHODS: We performed ICG iris angiography at several points during systemic chemotherapy for a 67-year-old man who had been diagnosed as having small-cell carcinoma of the lung with metastatic iris tumors. RESULTS: ICG iris angiography clearly demonstrated hyperfluorescent tumor vessels, rubeosis iridis, and dilated iris stromal vessels. After chemotherapy, these hyperfluorescent vessels and rubeosis regressed. CONCLUSION: ICG iris angiography appears to be an effective and useful method for observing abnormal vessels associated with metastatic iris tumors.

Aged↗
PubMed1999

Time course of endothelin-1 and adrenomedullin after the Fontan procedure.

BACKGROUND: The endothelium-derived vasoconstrictor endothelin (ET)-1 might contribute to the physiology of blood flow regulation and play a role in cardiovascular disease. Adrenomedullin (AM) is a potent vasodilator peptide that has major effects on cardiovascular function and has multiple biologic effects involved in cardiovascular homeostasis. Although pulmonary vascular resistance is known to be one of the most important factors to determine the indications for a Fontan procedure, the time course of the plasma cytokine before and after the Fontan procedure is not known. METHODS: Sixteen patients were divided into two groups, 8 patients (1 to 14 years) who had the Fontan procedure (atriopulmonary connection) and 8 age-matched controls who had biventricular repair with normal central venous pressure. Plasma ET-1 and adrenomedullin levels were measured in both groups immediately before cardiopulmonary bypass, immediately after cardiopulmonary bypass, and 6 and 24 hours after cardiopulmonary bypass. A thermodilution catheter was inserted during the operation, and mean pulmonary arterial pressure, pulmonary wedge pressure, and cardiac output were measured, and pulmonary vascular resistance was calculated at the same time points. Correlation between the plasma ET-1 levels and pulmonary vascular resistance data were obtained in the Fontan group. RESULTS: Plasma ET-1 levels in the Fontan group were elevated after operation and were higher than the control group at 6 and 24 hours after cardiopulmonary bypass. Plasma adrenomedullin in the Fontan group was lower than in the control group at 6 and 24 hours after cardiopulmonary bypass. A significant positive correlation was obtained between the plasma ET-1 and pulmonary vascular resistance data (r = 0.475). CONCLUSIONS: Imbalance between increased ET-1 and relatively decreased adrenomedullin after cardiopulmonary bypass in the Fontan procedure could contribute to dominant effects of ET-1, which might induce vasoconstriction after the Fontan procedure. ET-1 might play an important role in maintaining vasoconstriction after the Fontan procedure.

Adolescent↗
PubMed1999

Antioxidants from Lespedeza homoloba. (I).

The stems of Lespedeza homoloba yielded eight new and three known phenolic compounds. Their structures have been elucidated on the basis of their spectral data. These compounds had strong antioxidative activity against lipid peroxidation in the rat brain homogenate test. 3,9-Dihydroxypterocarp-6a-en and lespedezol A2 showed significant antiallergic activity in allergic (type I) mice.

Animals↗
PubMed1999

Possible involvement of a sigma receptor subtype in the neck dystonia in rats.

To clarify which subtype of sigma receptors is involved in the sigma receptor-mediated neck dystonia in rats, we examined whether 1-(3,4-dimethoxyphenethyl)-4-(3-phenylpropyl)piperazine dihydrochloride (SA4503), a selective sigma1 receptor agonist, and 1,3-di-(2-tolyl)guanidine (DTG), a sigma1 and sigma2 receptor agonist, induce neck dystonia in rats. Microinjection of SA4503 into the red nucleus of rat brain scarcely produced neck dystonia at the concentration of 10 nmol/0.5 microl. On the contrary, DTG produced significant dystonia at a concentrations of more than 5 nmol/0.5 microl. These results indicate that the sigma2 receptor subtype, but not sigma1 receptor subtype, may play an important role in the sigma receptor-mediated neck dystonia in rats.

Animals↗
PubMed1999

Solitary fibrous tumor of the buccal mucosa: report of a case with immunohistochemical studies.

We describe a case of a solitary fibrous tumor of the buccal mucosa and report the results of immunohistochemical studies of the lesion. Solitary fibrous tumors are extremely rare in the intraoral region. These tumors are generally difficult to diagnose because of their broad range of morphologic characteristics. We regard the expression of CD34 within the appropriate clinical and morphologic setting, in the absence of reactivity for other specific markers of differentiation, as evidence supporting the diagnosis of solitary fibrous tumor.

Adult↗
PubMed1999

Molecular typing of Escherichia coli O157:H7 (H-) isolates from cattle in Japan.

A total of 77 Escherichia coli O157:H7 (H-) isolates from cattle in Japan were investigated by molecular biological methods. Most of these isolates (43 isolates) possessed the stx-2 gene, but not stx1. Fifteen bacteriophage types and 50 pulsed-field gel electrophoresis (PFGE) profiles were observed. One isolate was indistinguishable from the human outbreak strain by these methods. This indicates that cattle must be considered as a possible source of human E. coli O157:H7 infection in Japan.

Animals↗
PubMed1999

The shift of genetic subtypes of Escherichia coli O157:H7 isolates from cattle.

A total of 46 Escherichia coli O157:H7 isolates were obtained from sequential faecal samples from seven cattle collected over periods of 2 months. Nine closely related genetic subtypes, determined by pulsed-field gel electrophoresis types using three kinds of restriction endonuclease were observed among the isolates. Distinguishable, but closely related genetic subtypes can be isolated from one farm, or from one cow, should be considered when undertaking an epidemiological survey.

Animals↗
PubMed1999

Histopathologic aspects of endomyocardial biopsy in pediatric patients with idiopathic ventricular tachycardia.

PURPOSE: The present study aimed to investigate the clinicopathologic findings and histopathologic characteristics of endomyocardial biopsy in pediatric patients with idiopathic ventricular tachycardia. METHODS: Histopathological findings of endomyocardial biopsy from 17 patients aged 7-15 years with idiopathic ventricular tachycardia (VT) but no organic heart disease were examined. Patients considered to have cardiomyopathy of the dilated, hypertrophic or specific form or arrhythmogenic right ventricular cardiomyopathy were excluded from this study. RESULTS: Advanced histopathologic findings, including myocyte hypertrophy, degeneration, interstitial fibrosis and disarrangement of muscle bundles, were disclosed in three cases (17.6%). One of these cases exhibited sustained VT with left bundle branch block configuration and showed increased frequency of VT during exercise testing. The remaining two cases had non-sustained VT with multifocal origin and had syncope episodes. Another 14 cases showed mild or no significant findings in the biopsy. CONCLUSIONS: These results indicate that advanced histopathology in endomyocardial biopsy is occasionally disclosed in cases of idiopathic VT, especially those of exercise-related VT or multifocal VT, and that these patients may be considered as having heart muscle disease.

Adolescent↗
PubMed1999

Response of skin blood volume, velocity and flow to local warming in newborns, measured by laser Doppler flowmetry.

BACKGROUND: In order to know the response of the skin microcirculation to local warming, we determined changes in the skin blood volume (Vol), velocity (Vel) and flow (F) by using a new laser Doppler device on newborns. METHODS: The study subjects were 39 infants whose gestational age was 34.1 +/- 2.8 weeks and birth weight was 2189 +/- 572 g. The study was performed from 8 h postnatally to 28 postnatal days. We measured skin blood volume, velocity and flow at 36 degrees C (Vol36, Vel36, F36), and each value at 5 min (Vol44-5, Vel44-5, F44-5) and 10 min (Vol44-10, Vel44-10, F44-10) after local warming was applied at 44 degrees C and the response curve of each parameter was obtained. Subsequently, serial changes in the response of skin microcirculation to local warming were investigated in nine very low birth weight (VLBW) infants (28.3 +/- 0.9 weeks, 1150 +/- 148 g) and 12 low birth weight (LBW) infants (32.8 +/- 1.3 weeks, 1971 +/- 292 g). The F36, the increment rate of blood volume (delta Vol) and the increment rate of blood velocity (delta Vel) were obtained within 24 h, from day 1 to day 7 and from day 8 to day 30 in both VLBW and LBW infants and from day 31 to day 60 and at more than 61 days in VLBW infants. The F36, delta Vol and delta Vel were compared during the study periods in VLBW and LBW infants. All results were expressed as mean +/- SD. RESULTS: The results showed that F36/F44-10 and F44-5/F44-10, Vol36/Vol44-10 and Vol44-5/Vol44-10, Vel36/Vel44-10 and Vel44-5/Vel44-10 were 0.25 +/- 0.09 and 0.74 +/- 0.17, 0.58 +/- 0.14 and 0.94 +/- 0.08, 0.42 +/- 0.12 and 0.79 +/- 0.15, respectively. Different modes of delivery did not have a significant effect on this response. The F36 in VLBW infants was high during the early neonatal period and gradually decreased with postnatal age. The delta Vol was low in VLBW infants during the neonatal period and gradually increased. The F36 in VLBW1-7 was significantly higher than in LBW1-7 (P < 0.01) and full-term controls (P < 0.001). The delta Vol in VLBW1-7 was 0.26 +/- 0.23, which is significantly lower than in LBW1-7 (0.57 +/- 0.17, P < 0.001) and full-term controls (0.77 +/- 0.21, P < 0.001). The delta Vel in VLBW1-7 and LBW1-7 was significantly higher than in controls (P < 0.05). CONCLUSIONS: The skin blood flow increased continuously when local warming was applied at 44 degrees C. This high blood flow and limited potential of vasodilatation are the characteristics of the skin microcirculation in VLBW infants during the neonatal period.

Blood Flow Velocity↗
PubMed1999

[Chromophobe cell renal carcinoma: a case report].

A 61-year-old man was admitted to our hospital because of the left renal mass lesion. We performed left radical nephrectomy under the diagnosis of renal cell carcinoma. The tumor showed a dark red color. The pathological diagnosis was chromophobe cell renal carcinoma. We could not make the diagnosis before the operation by echography, computed tomography or magnetic resonance imaging. It is still controversial whether this diagnosis can be made preoperatively.

Carcinoma, Renal Cell↗
PubMed1999

[Cerebral infarction accompanied by dysgeusia--a clinical study on the gustatory pathway in the CNS].

Dysgeusia was investigated in 11 patients with thalamic infarction and 13 patients with corona radiata infarction to locate the gustatory pathways based on the sites of the lesions. Dysgeusia was present in 4 out of 11 patients with thalamic infarction and 3 out of 13 patients with corona radiata infarction. The dysgeusia was contralateral to the lesion in all these patients. Cheiro-oral syndrome was observed as a complication in 2 patients each from both groups. The responsible lesion was located on the medial side of the ventral posterolateral (VPL) nucleus and the ventral posteromedial (VPM) nucleus in the patients with thalamic infarction who developed dysgeusia, and was located posteriorly to the corona radiata in the other group. In the patients without gustatory disturbance, on the other hand, the lesions showed no such spread. These findings suggest that the gustatory pathway ascends contralaterally in the cerebral hemisphere and that the pathway from the thalamus projects to the cerebral cortex via the posterior part of the corona radiata. It is also suggested that the pathways in the thalamus and corona radiata are very close to the sensory fibers from the mouth and hands projecting to the sensory area.

Aged↗
PubMed1999

[Validation and optimization of the use of standardized arterial input function in N-isopropyl-p[123I]iodoamphetamine cerebral blood flow SPECT].

UNLABELLED: Use of a standardized arterial input function and calibrating it by a single blood sample has been proposed to assess quantitatively cerebral blood flow using N-isopropyl-p[123I]iodoamphetamine (IMP) and single-photon emission computed tomography. This study was intended to validate this approach using a larger number of measured arterial radioactivity curves in the clinical setting. METHOD: Arterial input function was measured for 50 patients at rest following the i.v. IMP, and its inter-subject variation was assessed. Difference between smokers and non-smokers in addition to effects of acetazolamide administration were particularly investigated. We also evaluated the accuracy of the calibration procedures by means of either a single blood sample or a continuous arterial blood withdrawal sampling for an early period. RESULTS: Inter-subject variation of the observed arterial input function appeared not to show large variations among the 50 patients, thus suggesting the validity of using the standardized arterial input function for the IMP SPECT study. There was a significant difference in the shape of the arterial input function between the smokers and non-smokers, but the calibration at an optimized sampling time provided the area-under-the curve (AUC) that was not significantly different between the two groups. The arterial input function after the acetazolamide showed no significant difference as compared with the shape at rest. The calibration of the standardized input function by means of the early integration of individual curve did not show better accuracy except for a short period of AUC (i.e., < 20 min) for longer integration period > 10 min. CONCLUSION: Thus, use of the standardized arterial input function has been validated for the IMP SPECT study. The single blood sampling procedure for calibrating the standardized input function has also been validated, and has been shown to provide better accuracy compared with the continuous withdrawal procedure.

Adult↗
PubMed1999

Automated Processing of 2-D Gel Electrophoretograms of Genomic DNA for Hunting Pathogenic DNA Molecular Changes.

We have developed the automated processing algorithms for 2-dimensional (2-D) electrophoretograms of genomic DNA based on RLGS (Restriction Landmark Genomic Scanning) method, which scans the restriction enzyme recognition sites as the landmark and maps them onto a 2-D electrophoresis gel. Our powerful processing algorithms realize the automated spot recognition from RLGS electrophoretograms and the automated comparison of a huge number of such images. In the final stage of the automated processing, a master spot pattern, on which all the spots in the RLGS images are mapped at once, can be obtained. The spot pattern variations which seemed to be specific to the pathogenic DNA molecular changes can be easily detected by simply looking over the master spot pattern. When we applied our algorithms to the analysis of 33 RLGS images derived from human colon tissues, we successfully detected several colon tumor specific spot pattern changes.

Journal Article↗
PubMed1998

Sympathetic denervation and reinnervation after arterial switch operation for complete transposition.

BACKGROUND: Sympathetic cardiopulmonary nerves arise from the cervical sympathetic trunks and the stellate ganglia and subsequently course along the origin of the great arteries and the coronary arteries to innervate the ventricles. Therefore, the sympathetic nerves may be obligatorily interrupted by the arterial switch operation (ASO) for complete transposition of the great arteries. METHODS AND RESULTS: To demonstrate and characterize the possible sympathetic denervation, 51 patients after ASO, 4.8 years old (range, 1 month to 10.1 years), underwent [123I]metaiodobenzylguanidine (MIBG) imaging of the sympathetic nerve terminal. MIBG uptake to the heart was graded by quantitative analysis using the heart-to-mediastinum (H/M) ratio of MIBG uptake. A quantitative criterion for absent uptake of MIBG was set to 1.48 in the H/M ratio. Four patients < 1 month after ASO showed complete absence of MIBG uptake, which had been observed preoperatively. In contrast, 47 patients late after ASO (range, 15 months to 10.1 years) showed various degrees of uptake of MIBG. Patients operated on at < or =55 days of age showed positive MIBG uptake much more frequently than those operated on at later ages. Heart rate and rate-pressure product at peak exercise on a treadmill exercise test were significantly greater in patients with positive uptake than in those with absent uptake of MIBG. CONCLUSIONS: Cardiac sympathetic nerves were denervated early after and reinnervated late after ASO. Neonatal ASO may be favorable to facilitate sympathetic reinnervation, which may affect exercise tolerance late after surgery.

3-Iodobenzylguanidine↗