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T Takamatsu

Publications and source records attributed to T Takamatsu.

At least 37 records · Page 2Linked to original sources
PubMed1999

Detection and evaluation of asymptomatic myocarditis in schoolchildren: report of four cases.

STUDY OBJECTIVE: Data on the prevalence of myocarditis in children are limited. Autopsy studies have shown that myocarditis is often undiagnosed. We attempted to investigate the clinical features of asymptomatic myocarditis in four schoolchildren detected during a mass ECG screening in schoolchildren. DESIGN AND SETTING: To evaluate asymptomatic myocarditis, we clinically examined 12 schoolchildren who were referred to Shiga University of Medical Science Hospital, Otsu, Japan, because of abnormal ST or T waves detected during ECG screening. None of the 12 children had experienced any episodes suggesting cardiac disease or Kawasaki disease. Cardiac function and myocardial viability were assessed by two-dimensional echocardiography (2-DE), thallium-201 (201Tl) myocardial scintigraphy, and cardiac catheterization. Endomyocardial biopsy specimens were examined histologically. PATIENTS: Endomyocardial biopsy specimens revealed histologic evidence of myocarditis in 4 of the 12 children with abnormal ST or T waves. RESULTS: Abnormal tracer perfusion was observed on 201Tl myocardial scintigrams in these four children, but the results of coronary arteriography were normal. 2-DE showed left ventricular hypokinesis in one child and left ventricular enlargement in one of the four children with histologic evidence of myocarditis. A second endomyocardial biopsy specimen was obtained in two of four children, showing persistent myocarditis in one child. CONCLUSIONS: This type of screening program and indepth evaluation using 2-DE and 201Tl myocardial scintigraphy appear to be helpful in identifying children with myocarditis. The present histologic investigations suggested that even asymptomatic myocarditis might result in persistent heart damage.

Biopsy↗
PubMed1998

Regulation of cytosol-nucleus pH gradients by K+/H+ exchange mechanism in the nuclear envelope of neonatal rat astrocytes.

In order to study the subcellular heterogeneity of intracellular H+ concentration in reactive astrocytes, the pH in the nucleus and cytosol of cultured astrocytes was measured using a confocal laser scanning microscope (CLSM) and pH indicator dye, 5'(and 6')-carboxyseminaphthofluorescein (carboxy SNAFL-1). The change in intracellular pH was indexed by the fluorescence ratio (F535/F610) at an excitation wavelength of 514.5 nm. The in vitro fluorescence ratio increased as pH decreased. This ratio in the nucleus was significantly lower than that in the cytosol of astrocytes when perfused by HEPES-buffered Hanks' balanced salt solution (HHBSS) at pH 7.4. Acid stimulations of cells (pH 5.0) raised the fluorescence ratio in both nucleus and cytosol. However, the increase in the fluorescence ratio of the nucleus was less than that of cytosol. Treatment with a K+/H+ ionophore, nigericin (20 microM), reversibly nullified this cytosol-nucleus pH gradient. These findings suggest that a buffering mechanism(s) for maintaining of intracellular pH exists between the nucleus and cytosol, and a K+/H+ exchanger may act on the nuclear envelope to eventuate intranuclear pH maintenance in the living cells.

Animals↗
PubMed1998

Human neuroblastoma demonstrating clonal evolution in vivo.

Neuroblastoma demonstrates various clinical behaviors, ranging from spontaneous regression to rapid progression regardless of the therapy used. To study the possibility that progression occurs in neuroblastoma through the accumulation of genetic aberrations, we analyzed the clonal constitution of the primary tumor and metastatic tumor samples from a stage-4 patient. Using cytofluorometry and FISH analyses, intratumor clonal heterogeneity was revealed. In the initial primary tumor sample, the nuclear DNA content indicated the coexistence of diploid and aneuploid clones, and the copy number of chromosome 1 varied from two to six. The chromosome 1 aneusomy population was composed of MYCN-amplified and 1p-deleted clones, whereas, in the chromosome 1 disomy population, coexistence of MYCN-amplified and non-amplified clones as well as 1p-deleted and 1p-intact clones was revealed. In the primary tumor after chemotherapy, the DNA-diploid component had become predominant, although the coexistence of MYCN-amplified and non-amplified clones could still be demonstrated in poorly- and well-differentiated tumor regions, respectively. This contrasted with the findings in the metastatic tumors, in which either diploid or aneuploid clone with MYCN amplification and 1p deletion dominated completely in each metastatic site. The findings suggest that the aneuploid clones had evolved from a diploid clone with MYCN amplification and a 1p deletion which, in turn, may have evolved from a diploid clone with neither MYCN nor 1p abnormality. This illustrates how various stages of multiple-step tumorigenesis may provide clues to a better understanding of the clinical heterogeneity of neuroblastoma.

Child, Preschool↗
PubMed1998

Value of iodine-123 metaiodobenzylguanidine scintigraphy in patients with vasospastic angina.

To assess the presence and location of presynaptic myocardial sympathetic abnormality in patients with vasospastic angina, iodine-123 labelled metaiodobenzylguanidine (MIBG) single-photon emission tomography (SPET) was performed. Fifty patients suspected of having vasospastic angina pectoris were enrolled in the study. All patients underwent a provocative test with intracoronary ergonovine infusion during coronary angiography, in which 99%-100% obstructive spasm was defined as a positive result. Twenty-five patients were diagnosed as having vasospastic angina based on a positive provocative test. MIBG SPET was performed at 20 min and 3 h after administration of 111 MBq or MIBG. On early images, only 5 of 25 patients with vasospastic angina showed a mild reduction in MIBG uptake, whereas 3-h delayed images demonstrated MIBG abnormality in 20 patients (80%). The location of the MIBG abnormality was completely or partially consistent with the spastic coronary territory in 18 patients. On the other hand, only 4 of 25 patients (16%) with negative provocative test demonstrated reduced MIBG uptake. Accordingly, positive and negative predictive values of MIBG SPET for the provocative test were 83% (20/24) and 81% (21/26) respectively. In conclusion, MIBG scintigraphy with SPET can permit the non-invasive detection and evaluation of suspected vasospastic angina.

3-Iodobenzylguanidine↗
PubMed1998

Regulation of apoptotic cell death in the pyloric glands of the canine stomach.

In gastrointestinal epithelia, apoptosis has been thought to play a part in the shedding of postmitotic cells into the lumen. However, we have found that apoptosis more frequently in the generative cell (G) zone (the lower one third of the pit) than in the luminal zone (the upper one third of the pit) and the gland zone in the canine pyloric gland. To analyse the regulation of apoptotic cell death in each zone, we labelled S-phase cells by single and repeated injections of bromodeoxyuridine (BrdU) i.v. at intervals of 8 h. We found that 30% of apoptoses in the G zone were flash-labelled by BrdU and might derive from cells in or just after the S phase. The incidence of apoptosis and mitotic index did not change significantly after repeated injections of BrdU until the 49-h point, when the incidence of apoptosis increased and the mitotic index decreased significantly in the G zone, while the incidence of apoptosis decreased in the luminal zone. The BrdU-induced increase of apoptosis and cell-cycle arrest at the 49-h point may be caused by enhanced DNA mispairs that are elicited by incorporation of BrdU, in particular using the template of BrdU incorporated DNA. Apoptosis in the luminal zone may be down-regulated by reduced cell production in the G-zone.

Animals↗
PubMed1998

Real time in situ confocal imaging of calcium wave in the perfused whole heart of the rat.

To understand the calcium handling in whole heart having automaticity of the sinus node, we have developed a system of in situ imaging the intracellular calcium ion concentration in the perfused whole heart of the rat. The system consists of a stage-fixed upright microscope equipped with a real-time confocal laser scanning device of a multipinhole type with a water-immersion objective lens for observation. This in situ imaging system rendered observations and analyses of the rapidly changing images of intracellular calcium dynamics possible in the whole rat heart loaded with fluo-3. The scanning was conducted at a video rate of 30 frames per second, and the confocal effects included both X and Y planes. Calcium waves were frequently interrupted by calcium transients from either external electro-stimulation pulses or spontaneous sinus rhythm. Our findings suggest that abnormal calcium waves in minute areas cannot disturb the excitation-contraction coupling in the whole heart if the myocardial cells have orderly end-on-end intercellular electric paths.

Animals↗
PubMed1998

Confocal microscopy. Applications in research and practice of pathology.

OBJECTIVE: To discuss recent advances in the use of confocal microscopy to perform quantitative analysis of physiologic and pathologic intracellular events in the living organ. STUDY DESIGN: We developed a new confocal microscope system equipped with a microlens-arrayed multipinhole scanning disc and water-immersion objective lenses. The confocal microscope enables us to quantitate nonhomogeneous changes in the three-dimensional intracellular calcium ion concentration in a living, whole heart. RESULTS: The new system allows in situ quantitative imaging of the calcium wave in the living heart at a full video rate. Calcium waves propagating from cell to cell were frequently interrupted by calcium transients from spontaneous sinus rhythm, but low transparency of the living tissues and cell injury with laser light still remained unsolved. CONCLUSION: The evolution of the confocal microscope with high spatial and temporal resolution renders the investigation of biologic phenomena even in the living organ.

Calcium↗
PubMed1997

Direct retinal projections to GRP neurons in the suprachiasmatic nucleus of the rat.

The retinal projections to gastrin-releasing peptide (GRP)-expressing neurons in the rat suprachiasmatic nucleus (SCN) were investigated by double immunofluorescence and immunoelectron microscopy. Optic nerve terminals labeled by cholera toxin B subunit (CTb) which was transported from the retinal ganglion cells were intermingled with GRP-immunoreactive cell bodies and processes in the ventrolateral portion of the SCN. Ultrastructural analysis revealed that CTb-immunoreactive retinal terminals made synaptic contacts with GRP-immunoreactive dendritic processes. These results demonstrated that photic information is directly input from the optic nerve to GRP neurons in the SCN and these GRP neurons may be involved in circadian entrainment by light.

Animals↗
PubMed1997

Study of salivary catecholamines using fully automated column-switching high-performance liquid chromatography.

Cortisol and catecholamines are major physiological markers of human stress. In order to establish a fully automated assay system for both cortisol and catecholamines in saliva, which can be sampled without imposing stress, the previously developed system for salivary cortisol [Okumura et al., J. Chromatogr. B, 670 (1995) 11] was modified. The practical sensitivity was around 0.1 pmol ml(-1) for norepinephrine and epinephrine and 0.5 pmol ml(-1) for dopamine. The established assay procedure provided R.S.D. values of 2 approximately 3% and recoveries of 96 approximately 104% at 0.5 pmol ml(-1). Measurement of salivary catecholamines in more than 300 samples taken from about 50 healthy volunteers indicated that the normal values of norepinephrine and dopamine were very low, about 0.1 pmol ml(-1) each. In contrast to cortisol, salivary catecholamine levels did not parallel those in plasma. Nevertheless, since levels of salivary catecholamines may reflect the sympathetic nerve activity in the salivary gland, they were assayed in volunteers making a scientific presentation before a large audience. Four out of eleven volunteers reported strong feelings of fear or anxiety, and their salivary catecholamine levels were about ten times higher than normal.

Adult↗
PubMed1997

Ischaemia-induced temporal expression of connexin43 in rat heart.

To investigate the regulation of cell-to-cell coupling in myocardial ischaemia, the three-dimensional expression of connexin43 (Cx43) during experimental ischaemia was examined using a confocal laser scanning microscope. After induction of myocardial infarction in rats, serial optical sections were obtained from the left ventricular myocardium at various times (3 h to 60 days after ligation). The expression of Cx43 was detected immunohistochemically with FITC-labelled anti-rat Cx43 antibody. Fluorescent dots of Cx43 remained along the intercalated disc and decreased in number around the infarct up to 12 h after ligation. Cx43-expression disappeared completely within 48 h after ligation. After day 4, and especially on days 8 and 15 after ligation, the edges of the cardiomyocytes bordering the infarcted area manifested numerous sarcoplasmic tentacles that reacted positively to anti-desmin antibody. Distinct expression of Cx43 was observed extensively on the tentacles, although no cardiomyocytes remained viable around them. By day 60 after ligation, atypical expression of Cx43 had disappeared. These findings suggest that ischaemia induces temporally abnormal expression of Cx43, which might be responsible for abnormal conduction around the infarct.

Animals↗
PubMed1997

Temporal and spatial patterns of phosphotyrosine immunolocalization during cardiac myofibrillogenesis of the chicken embryo.

To investigate the possible role of phosphorylation of protein tyrosine during myofibrillogenesis (6- to 13-somite stages) of the chicken embryonic heart tube, immunolocalization of phosphotyrosine (P-Tyr) and the relationship between P-Tyr and developing myofibrils were studied by means of confocal scanning laser microscopy and immuno-electron microscopy. The staining pattern of P-Tyr varied in different sites of myocytes at different stages of embryonic development: At the cell-cell boundaries, P-Tyr was localized at the adhesion belt of outer myocardial layer cells (6- to 13-somite stages), non-junctional cell-cell contacts (6- to 13-somite stages) and early intercalated disks of both the outer and inner myocardial layer cells (8- to 13-somite stages). At the cell-extracellular matrix boundaries of inner layer cells, the first stages of myofibril formation appeared as serially aligned areas of P-Tyr localization closely associated with circumferentially aligned thick actin bundles (8- to 9-somite stages). This P-Tyr immunostaining decreased when the thick actin bundles developed into mature striated myofibrils at the 10- to 13-somite stages. These findings suggest that the phosphorylation of protein tyrosine residues is primarily concentrated at the modulating cell-cell and cell-matrix adhesion sites of developing myocytes and myofibrils.

Actins↗
PubMed1997

Effects of basal [Ca2+]i on calcium handling in Ca(2+)-overloaded rat cultured heart muscle cells.

To elucidate the relationship between intracellular free Ca2+ concentration ([Ca2+]i) and Ca(2+)-signalling by the sarcoplasmic reticulum (SR) in Ca(2+)-overloaded heart muscle cells, the direct effects of "basal" [Ca2+]i on calcium waves were investigated by altering the membrane potential. When basal inter-calcium wave (BCW) [Ca2+]i was maintained at a high level, (i) calcium waves showed more gradual and more rapidly suppressed increase in [Ca2+]-profile (P < 0.005), and (ii) calcium waves occurred at a significantly higher frequency and velocity (259% and 137%), than when low BCW [Ca2+]i was maintained. Similar investigations on inhibition of the Na(+)-Ca2+ exchanger, however, showed that membrane potential did not elicit direct effects on calcium waves. These results showed that the elevation of BCW [Ca2+]i per se directly influences Ca(2+)-signalling in heart muscle cells through non-equilibrated release-restoration Ca(2+)-handling by the SR.

Aniline Compounds↗
PubMed1997

Evolution of coronary vascular tone in vasospastic angina.

In general, anginal symptoms diminish with time in patients with vasospastic angina. We assessed changes in coronary vascular tone (CVT) in patients with vasospastic angina over a 4-year period to evaluate the time course of spastic activity. Vasospastic angina was evaluated in 39 patients in whom occlusive spasm was evoked by selective intracoronary injection of ergonovine maleate (ERG-S) 48 h after stopping all coronary vasodilator drugs. These patients had no organic coronary stenosis and developed no stenosis during follow-up. ERG-S was repeated 3 times at 2-year intervals. CVT was determined at each ERG-S study using the equation: CVT = 1-(coronary artery diameter before ERG-S/coronary artery diameter after intracoronary injection of isosorbide dinitrate). Thirty-four patients (87%) had no angina pectoris at the second ERG-S study and 28 (72%) had none at the third. Coronary spasm was induced in 25 patients at the second ERG-S study and in 20 at the third. The overall CVT was shown to decrease at each successive ERG-S study (p < 0.01). There was no correlation between changes in CVT and anginal symptoms or the coronary spasm induction rate. These results demonstrate that CVT decreases over time in patients with vasospastic angina, suggesting that myocardial ischemia may improve spontaneously.

Aged↗
PubMed1996

Structural characterization and location of disulphide linkages of a potent vasodilatory peptide, recombinant maxadilan, by a multiple mass spectrometric approach.

A multiple mass spectrometric strategy using fast-atom bombardment (FAB) and matrix-assisted laser desorption/ionization (MALDI) has been used to confirm the sequence and to locate the disulfide linkages of recombinant maxadilan (r-maxadilan) (average molecular mass 7422.5 Da), a potent vasodilatory peptide from Lutzomyia longipalpis. MALDI measurements of intact r-maxadilan, its reduced form and its pyridylethylated form (p-maxadilan) indicated the presence of four Cys residues without major post-translational modifications. FAB and FAB-tandem mass spectrometry measurements of chymotryptic digests of p-maxadilan were sufficient to map the primary structure of p-maxadilan, though the complementary use of MALDI was necessary for complete mapping using Asp-N digestion due to a strong suppression observed in FAB. Assignment of the Cys-5-Cys-9 linkage was achieved by comparison of FAB mass spectra before and after reduction of tryptic digests of r-maxadilan. Since the molecular weight of the peptide fragment containing the Cys-18-Cys 55 linkage is more than 4000, MALDI measurement was indispensable for assignment of this linkage. The results fully support the value of the multiple mass spectrometric strategy in the structural characterization of peptides and proteins.

Amino Acid Sequence↗
PubMed1996

[Endovascular stenting for a recurrent angina patient].

We report successful Palmaz-Schatz stenting for recurrent angina. Coronary arteriography in a 65-year-old man with recurrent angina six months after coronary artery bypass grafting (CABG) showed stenosis in the right coronary artery and in the saphenous vein graft to the left anterior descending artery. For both stenotic lesions, balloon dilatation was performed. However, both lesions recoiled after dilatation. Therefore, Palmaz-Schatz stents were inserted in both stenotic lesions. After stenting, the patient did not experience any further chest pain. Three months later coronary arteriography showed the stents remained patient. Balloon angioplasty for post-CABG angina is technically easier than additional surgery. However, angioplasty by balloon dilatation alone can induce dangerous complications during the acute phase and restenosis frequently develops. This method is not sufficiently effective or safe for recurrent angina. To prevent these problems, the stent was developed as a useful adjunct to balloon dilatation for the native artery. Using this new device, angioplasty for recurrent angina will be safer and more effective than additional surgery.

Aged↗
PubMed1995

Column-switching high-performance liquid chromatographic system with a laser-induced fluorimetric detector for direct, automated assay of salivary cortisol.

In order to measure human stress, an easy and rapid, fully automated method for the determination of cortisol in saliva has been developed, using column-switching high-performance liquid chromatography with laser-induced fluorescence detection, which involves post-column labeling with sulfuric acid. The developed system requires only 0.1 ml of saliva, and a simple pretreatment consisting of dilution and filtration is sufficient. The column-switching system consisted of a Polymer-Coated Mixed-Functional silica (PCMF) column for deproteinization, and a CN column for frontal concentration and separation. An ODS column in place of the CN provided a better separation, but required a post-column make-up of water for safe reaction. Detection limit of cortisol was 8 fmol (signal-to-noise ratio = 3), which is adequate for routine determination of normal levels of cortisol (1-20 pmol/ml). The analysis time was about 40 min and reproducibility was excellent with an R.S.D. of less than 5%.

Chromatography, High Pressure Liquid↗