Search PubMed⌕ Search

Biomedical subjects

H Matsuda

Publications and source records attributed to H Matsuda.

At least 307 records · Page 17Linked to original sources
PubMed2000

[Efficacy of aortic valve replacement with freestyle stentless valve in patients with aortic valve disease].

Stentless porcine aortic bioprosthesis has several potential advantages over conventional stented bioprosthesis. The Medtronic Freestyle aortic bioprosthesis, a stentless design analogous to an aortic allograft, has zero-pressure-fixed leaflets treated with an antimineralization agent, and has been shown to have benefits of superior effective orifice area, excellent flow characteristics and durability. To evaluate the early results for its efficacy in view of post-operative performance. The valve was implanted using the cylinder method, with subcoronary, root-inclusion techniques or full root techniques. No patients experienced any significant valvular regurgitation on echocardiography. The post-operative data of EDVI, ESVI and LVPWD decreased significantly as compared with the pre-operative data while ejection fraction remained unchanged. The average peak pressure gradient was 16.5 mmHg, and the average effective orifice area was 2.45 cm2. In conclusion, Freestyle stentless aortic bioprosthesis showed excellent hemodynamic function. It seems to be suited for the older patient with a small aortic annulus.

Aged↗
PubMed2000

[Heart transplantation; restarted in Japan].

The first heart transplantation after organ transplantation law was successfully carried out in February, 1999 in Japan. The case was a male patient with dilated phase of hypertrophic cardiomyopathy and had been supported by implantable left ventricular assist device for 4 months. The procurement of the heart was done at distant place and transportation required about 2 hours by helicopter. The operation was done uneventfully using Lower-Shumway method and the patient was discharged 75 days later and has returned to the previous work at 1 year follow-up.

Adult↗
PubMed2000

Longitudinal evaluation of early Alzheimer's disease using brain perfusion SPECT.

UNLABELLED: The aim of this SPECT study was to determine the initial abnormality and longitudinal changes in regional cerebral blood flow (rCBF) in early Alzheimer's disease (AD) using statistical parametric mapping (SPM). METHODS: rCBF was noninvasively measured using (99m)Tc-ethyl cysteinate dimer SPECT in 32 patients complaining of mild cognitive impairment, with a Mini-Mental State Examination score more than 24 at the initial study, and 45 age-matched healthy volunteers. All patients satisfied the diagnostic criteria of AD during the follow-up period of at least 2 y. Follow-up SPECT studies were performed on the patients at a mean interval of 15 mo. We used the raw data (absolute rCBF parametric maps) and the adjusted rCBF images of relative flow distribution (normalization of global cerebral blood flow [CBF] for each subject to 50 mL/100 g/min with proportional scaling) to compare these groups with SPM. RESULTS: In the baseline study, the adjusted rCBF was significantly and bilaterally decreased in the posterior cingulate gyri and precunei of patients compared with healthy volunteers. In the follow-up study, selected reduction of the adjusted rCBF was observed in the left hippocampus and parahippocampal gyrus. These areas showed the most prominent reduction in absolute rCBF on each occasion. Moreover, further decline of the absolute rCBF was longitudinally observed in extensive areas of the cerebral association cortex. CONCLUSION: SPM analysis showed the characteristic early-AD rCBF pattern of selective decrease and longitudinal decline, which may be overlooked by a conventional region-of-interest technique with observer a priori choice and hypothesis. This alteration in rCBF may closely relate to the pathophysiologic process of this disease.

Aged↗
PubMed2000

A multiple alignment algorithm for metabolic pathway analysis using enzyme hierarchy.

In many of the chemical reactions in living cells, enzymes act as catalysts in the conversion of certain compounds (substrates) into other compounds (products). Comparative analyses of the metabolic pathways formed by such reactions give important information on their evolution and on pharmacological targets (Dandekar et al. 1999). Each of the enzymes that constitute a pathway is classified according to the EC (Enzyme Commission) numbering system, which consists of four sets of numbers that categorize the type of the chemical reaction catalyzed. In this study, we consider that reaction similarities can be expressed by the similarities between EC numbers of the respective enzymes. Therefore, in order to find a common pattern among pathways, it is desirable to be able to use the functional hierarchy of EC numbers to express the reaction similarities. In this paper, we propose a multiple alignment algorithm utilizing information content that is extended to symbols having a hierarchical structure. The effectiveness of our method is demonstrated by applying the method to pathway analyses of sugar, DNA and amino acid metabolisms.

Algorithms↗
PubMed2000

Assessment of perioperative predictive factors influencing survival in patients with postinfarction ventricular septal perforation. Classified by the site of myocardial infarction.

BACKGROUND: The present study was designed to identify the perioperative factors and to consider a counterplan for the improvement of surgical results, based on the site of myocardial infarction. METHODS: Sixteen patients with postinfarction ventricular septal perforation underwent surgical repair. The operation was performed 5+/-3 days after the onset of ventricular septal perforation using the same method, an infarctectomy and reconstruction of the septum and right and left ventricular walls with a single Dacron patch. The ventricular septal perforation was anterior in 11 patients and posterior in 5. Preoperative hemodynamics between survivors and non-survivors were compared. Left ventricular wall motion was estimated using echocardiography by wall motion score (divided into 17 segments and each segment was graded on a fourpoint scale: normal, 0; hypokinetic, 1; severe hypokinetic, 2; a- or dyskinetic, 3) and summed up. RESULTS: The operative mortality was 36% in 11 patients with anterior ventricular septal perforation. In non-survivors compared to survivors, wall motion score was greater (25+/-4 vs 18+/-4, p<0.01) and all values were over 20. The value of the cardiac index divided by Qp/Qs was lower (0.98+/-0.09 vs 1.44+/-0.31, p<0.02) and all were under 1.1. In 5 patients with inferior ventricular septal perforation, the operative mortality was 40%. In non-survivors compared to survivors, wall motion score was greater (18, 18 vs 7, 2, 12) and the right atrial pressure was greater (18, 19 vs 10, 9, 9 mmHg) due to a right ventricular infarction. CONCLUSIONS: The patients with poor left ventricular wall motion were lost for reasons unrelated to the site of myocardial infarction. Moreover, a cardiac index over Qp/Qs in anterior ventricular septal perforation and the existence of a right ventricular infarction in inferior ventricular septal perforation was predictive of operative mortality.

Aged↗
PubMed2000

[SPECT and PET in Parkinson's disease].

In Parkinson's disease(PD) cerebral blood flow and glucose metabolic rate measurements using SPECT and PET have demonstrated functional abnormality in basal ganglia-thalamocortical and its related circuits. [123I] IBF SPECT and [11C] raclopride PET seemed promising tools to assessing D2 receptor status in humans. Studies of D2 status have demonstrated normal or increased receptor density in PD and decreased receptor density in multiple system atrophy. Marked differences of the dopamine transporters located on dopaminergic terminals in the striatum has been demonstrated in healthy controls and PD patients using SPECT. The correlation of SPECT measures of dopamine transporters and motor severity suggests that this may be an useful marker of disease severity in PD.

Biomarkers↗
PubMed2000

[Gene expression and the eye].

We examined the role of the expression of the various genes in ocular tissues using knockout mice. In this paper, the results are described in three sections: development, physiology, and pathology. Regarding development, the IKK alpha in the development of the ocular surface and maf family genes in the development of the lens were examined. We clearly demonstrated that the deletion of some genes results in disorganization in the development according to the function of the genes. Regarding physiology, c-fos gene was expressed in the subpopulation of retinal neurons under a physiological light/dark cycle, and its expression is dependent on signal transduction system in the retinal cells. Regarding pathology, focal retinal injury of the retina induced the expression of c-fos mRNA in retinal Müller cells. There is a significant contribution of Jun N-terminal phosphorylation to the induction of apoptosis of retinal ganglion cells after optic nerve transection. GLAST is required for normal signal transmission between photoreceptors and bipolar cells and both GLAST and GLT-1 play a neuroprotective role during ischemia in the retina. Blockage of the neurotrophin receptor p 75 rescue photoreceptor apoptosis induced by light exposure whereas the blockage of TrkC increased the photoreceptor cell death.

ATP-Binding Cassette Transporters↗
PubMed2000

Clinicopathological features of gastric stromal tumors.

Stromal tumors in the gastrointestinal (GI) tract consist of myogenic tumors, neurogenic tumors and gastrointestinal stromal tumors (GISTs). Mutations in the c-kit gene have been found in GISTs, and GISTs with c-kit mutations showed aggressive clinical behavior and histological features. In the present study, we classified stromal tumors into four groups according to histological differentiation and c-kit mutation: myogenic tumors, neurogenic tumors, c-kit mutation (-) GISTs and c-kit mutation (+) GISTs, and examined their clinicopathological importance and validity using data obtained from 125 patients with gastric stromal tumors. There was no difference in preoperative symptoms and signs among the four groups. GISTs with c-kit mutations were large and showed invasion into neighboring structures compared with the other tumors, indicating the clinically aggressive features of mutation (+) GISTs. In histological examinations, c-kit mutation (+) GISTs were higher in cellularity (P < 0.0001) and mitotic cell count (P = 0.0086), and showed frequent histological necrosis (P = 0.0058) and hemorrhage (P = 0.0170), and consequently, were higher in histological grade (P = 0.0001). In prognostic analyses, overall, cause-specific and disease-free survival of patients in the mutation (+) GIST group was the poorest among the four groups. No significant differences were found among the other three groups of myogenic tumors, neurogenic tumors and c-kit mutation (-) GISTs, indicating a similar aggressiveness in clinical presentation and histological features. Thus, this classification is considered to be clinically and pathologically important in the diagnosis of gastric stromal tumors.

Adult↗
PubMed2000

Direct in vivo visualization of glomerular microcirculation by intravital pencil lens-probe CCD videomicroscopy.

There have been developed several types of experimental techniques for evaluation of renal microcirculation. Although each methodology possesses excellent and unique characteristics, it requires substantial artificial manipulation that might alter the renal microvascular responsiveness. To circumvent such limitations of previous ex vivo or in vitro approaches to glomerular microcirculation, we have developed a pencil lens probe CCD intravital videomicroscopic system that allows us to evaluate both systemic hemodynamics and renal microcirculation. Furthermore, real time images of afferent and efferent arterioles as well as glomeruli can be continuously assessed, which would facilitate the functional characterization of these microvessels in vivo. Finally, the tapered nature of the CCD probe of this videomicroscopy may allow direct observation of the renal microvasculature in small animals. In conclusion, this novel technique is a valuable tool for unveiling the in vivo, in situ, and intact renal microvascular behavior, and may provide further approaches to the understanding of renal microcirculation.

Animals↗
PubMed2000

Prevalence of antibodies to Toxoplasma gondii among urban and rural residents in the Philippines.

A survey of antibodies to Toxoplasma gondii was carried out among residents in urban (Metro Manila) and rural (Mindoro and Leyte) areas in the Philippines. A total of 1,173 serum samples were examined for Toxoplasma antibody by an ELISA method. The overall seropositivity was 11.1% (n=904, 12.4% in males, 10.0% in females) in Metro Manila, 61.2% (n=152, 63.3% in males, 53.1% in females) in Mindoro, and 30.1% (n=113, 34.3% in males, 22.5% in females) in Leyte, indicating significantly higher (p<0.001) seropositivities in rural than urban settings. No significant differences in seropositivities were observed between males and females. In each group, seropositivity tended to increase with age of the subjects.

Adolescent↗
PubMed1999

Counterions of BINAP-Pt(II) and -Pd(II) complexes: novel catalysts for highly enantioselective Diels-Alder reaction.

[formula: see text] Platinum and palladium chiral bisphosphine complexes and their counterion effects in asymmetric Diels-Alder reactions have been investigated. The reaction of cyclopentadiene and various bidentate dienophiles in the presence of a catalytic amount of Pt(II)- or Pd(II)-BINAP complex proceeds with excellent endo/exo selectivity as well as endo enantioselectivity (up to 99% ee).

Catalysis↗
PubMed1999

Calmodulin activates intramolecular electron transfer between the two flavins of neuronal nitric oxide synthase flavin domain.

The neuronal NO synthase (nNOS) flavin domain, which has similar redox properties to those of NADPH-cytochrome P450 reductase (P450R), contains binding sites for calmodulin, FAD, FMN, and NADPH. The aim of this study is to elucidate the mechanism of activation of the flavin domain by calcium/calmodulin (Ca(2+)/CaM). In this study, we used the recombinant nNOS flavin domains, which include or delete the calmodulin (CaM)-binding site. The air-stable semiquinone of the nNOS flavin domains showed similar redox properties to the corresponding FAD-FMNH(&z.ccirf;) of P450R. In the absence or presence of Ca(2+)/CaM, the rates of reduction of an FAD-FMN pair by NADPH have been investigated at different wavelengths, 457, 504 and 590 nm by using a stopped-flow technique and a rapid scan spectrophotometry. The reduction of the oxidized enzyme (FAD-FMN) by NADPH proceeds by both one-electron equivalent and two-electron equivalent mechanisms, and the formation of semiquinone (increase of absorbance at 590 nm) was significantly increased in the presence of Ca(2+)/CaM. The air-stable semiquinone form of the enzyme was also rapidly reduced by NADPH. The results suggest that an intramolecular one-electron transfer between the two flavins is activated by the binding of Ca(2+)/CaM. The F(1)H(2), which is the fully reduced form of the air-stable semiquinone, can donate one electron to the electron acceptor, cytochrome c. The proposed mechanism of activation by Ca(2+)/CaM complex is discussed on the basis of that provided by P450R.

Binding Sites↗
PubMed1999

Function of human factor H and I on xenosurface.

The cell membrane-bound forms of mini-factor H with 1-4 short consensus repeats (fH-PI) and factor I (fI-PI) were constructed. Swine endothelial cell (SEC) lines and Chinese hamster ovary (CHO) cell expressing fH-PI or fI-PI were established and confirmed by flow cytometry. The cell lysate of the SEC line expressing fH-PI showed strong cofactor activity for the cleavage of C3b, and fI-PI demonstrated the protease activity for C4b and C3b not only in the fluid phase but also on the cell membrane. In addition, fH-PI blocked human complement-mediated cell lysis by approximately 30-40%. An SEC line with a low expression of fI-PI showed a weak inhibition of cell lysis in human serum, whereas a CHO cell transfectant with a high expression of fI-PI showed over a 60% inhibition of cell lysis. The results suggest that fH-PI and fI-PI have potential for use in clinical xenotransplantation.

Animals↗
PubMed1999

Activity of midbrain reticular formation and neocortex during the progression of human non-rapid eye movement sleep.

To clarify the neural correlates and brain activity during the progression of human non-rapid eye movement (NREM) sleep, we examined the absolute regional cerebral blood flow (rCBF) during light and deep NREM sleep and during wakefulness in normal humans using positron emission tomography with H(2)(15)O. Relative changes in rCBF during light and deep NREM sleep in comparison to the rCBF during wakefulness were also analyzed. During light NREM sleep, the rCBF in the midbrain, in contrast to that in the pons and thalamic nuclei, did not decrease when compared to that during wakefulness, whereas rCBF decreased in the left medial frontal gyrus, left inferior frontal gyrus, and left inferior parietal gyrus of the neocortex. During deep NREM sleep, the rCBF in the midbrain tegmentum decreased, and there was a marked and bilateral decrease in the rCBF in all neocortical regions except for the perirolandic areas and the occipital lobe. There have been three groups of brain structures, each representing one type of deactivation during the progression of NREM sleep. The activity of the midbrain reticular formation is maintained during light NREM sleep and therefore represents a key distinguishing characteristic between light and deep NREM sleep. Selective deactivation of heteromodal association cortices, including those related to language, occurs with increasingly deep NREM sleep, which supports the recent theory that sleep is not a global, but it is a local process of the brain.

Adult↗
PubMed1999

Effects of sesquiterpenes and triterpenes from the rhizome of Alisma orientale on nitric oxide production in lipopolysaccharide-activated macrophages: absolute stereostructures of alismaketones-B 23-acetate and -C 23-acetate.

The methanolic extract from a Chinese herbal medicine, the rhizome of Alisma orientale, was found to exhibit inhibitory activity of nitric oxide (NO) production in lipopolysaccharide (LPS)activated macrophages. Novel triterpenes, alismaketones-B 23-acetate and -C 23-acetate, were isolated from the active extract together with eight sesquiterpenes and eighteen protostane-type triterpenes. The absolute stereostructures of new triterpenes were characterized on the basis of chemical and physicochemical evidence, which included the chemical correlations with known triterpenes. The guaiane-type sesquiterpenes (alismol, orientalols A and C) and protostane- and seco-protostane-types triterpenes (alisols C monoacetate, E-23-acetate, F, H, I, L-23-acetate, and M-23-acetate, alismaketones-B 23-acetate and -C 23-acetate, alismalactone 23-acetate, and 3-methylalismalactone 23-acetate) inhibited LPS-induced NO production (IC50 = 8.4-68 microM). Other triterpenes (alisols A, A monoacetate, B, B monoacetate, E, G, K-23-acetate, and N-23-acetate and 11-deoxyalisol B) also showed the potent inhibitory activity, but they showed cytotoxic effects more than 30 microM (MTT assay). In addition, alismol and alisol F were found to suppress iNOS induction.

Animals↗