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Biomedical subjects

H Matsuo

Publications and source records attributed to H Matsuo.

At least 91 records · Page 5Linked to original sources
PubMed2000

Recognition and Management of Thrombosed Type of Aortic Dissection With Long-term Follow-up Results.

In a previous report we have stated that two distinct types of aortic dissection exist, namely the opened-communicated type (O-type) which demonstrates communication between the true lumen and the false lumen, and the thrombosed type (T-type, also known as aortic dissecting hematoma or as intramural hematoma). The latter, in its acute phase, shows no opacification of the false lumen through medical imagings such as CT scans or angiography. In previous studies we analyzed the long-term follow-up results of consecutive patients with aortic dissections at our hospital. During the past 14 years a study has been conducted of a total of 466 consecutive patients including 371 who were classified O-type and 95 who were classified as T-type. In 18 T-type patients (19%), complications such as cerebral ischemic episodes were observed. These were, however, transient and not serious, sometimes indicating only minor surgery. Only three T-type patients were indicated for surgery in the follow-up period, two because of the extension of a protruded lesion, and one because of the occurrence of redissection. Three of these died, but the actuarial survival rate of the T-type group was significantly higher than that of the O-type group. In conclusion, it can be stated that at the acute phase, a differentiation between the two types of dissection, ie, T-type and O-type, is important in the deciding of treatment.

Journal Article↗
PubMed2000

Surgical considerations of occlusive lesions associated with Takayasu's arteritis.

OBJECTIVE: Takayasu's arteritis is an inflammatory vascular disease of unknown etiology that affects the aorta and its main branches, requiring surgical intervention due to occlusive lesions. We studied early and late surgical results. METHODS: Between 1979 and December 1998, 46 patients--1 man and 45 women aged 15 to 72 years (mean: 46 +/- 13 years)--with occlusive lesions caused by Takayasu's arteritis underwent surgery. Preoperative steroids were administered to 22 patients having inflammation. Diagnosis indicating surgery included obstructive cervical vessel disease in 13 patients, obstructive coronary artery disease in 19, aortic coarctation in 15, and abdominal branch stenosis in 3. Surgical procedures involved bypass grafting in 31 (cervical vessel bypass in 13, ascending-abdominal aortic bypass in 4, axillary artery-abdominal aortic bypass in 10, descending-abdominal aortic bypass in 1, abdominal branch bypass in 3), coronary artery bypass grafting in 10, and coronary ostial endarterectomy in 9. RESULTS: Four (8.7%) died during hospitalization. Follow-up ranged from 1 to 240 months (mean: 117 months). Eight suffered late deaths and 6 patients died of cardiovascular problems. The total actuarial survival rate was 76.2% at 5 years and 70.5% at 10 years. CONCLUSIONS: Steroid therapy before and after surgery appears to affect the overall prognosis positively in patients with Takayasu's arteritis.

Adolescent↗
PubMed2000

Surgery in three-channeled aortic dissection. A 31-patient review.

OBJECTIVE: Three-channeled aortic dissection with 2 adjacent false lumens present is rare. METHODS: The 31 patients whose dissections we treated surgically accounted for 7.3% of the 426 patients with aortic dissection treated surgically between 1978 and May 1999. The 17 men and 14 women ranged in age from 24 to 77 years (mean: 45 +/- 12 years). Marfan syndrome was present in 18. Pain was observed at different times in 20. computed tomography scanning and magnetic resonance image proved useful in preoperative diagnosis. The morphology of the 1st and 2nd false lumens was Stanford type A + B in 13, type B + B in 15, type A + A in 2, and localized abdominal dissection in 1. RESULTS: Descending aortic replacement was done in 18 patients, thoracoabdominal aortic replacement in 7, ascending aortic replacement in 3, and others in 3. Five patients died in hospital and later during follow-up for 1-181 months (mean, 57 +/- 55 months). CONCLUSIONS: Pain recurring in patients with aortic dissection should alert the physician to the possibility of 3-channeled dissection and the necessity of surgery. The incidence of such dissection is high in patients with Marfan syndrome.

Adult↗
PubMed2000

Preservation of the right atrial appendage improves reduced plasma atrial natriuretic peptide levels after the maze procedure.

OBJECTIVES: The present study was conducted to determine whether preservation of the right atrial appendage lessens the decrease of plasma atrial natriuretic peptide levels after the maze procedure and whether the increase of plasma atrial natriuretic peptides improves the ability of the kidneys to excrete the fluid load after the operation. METHODS: We evaluated 42 patients who underwent the maze procedure. The right atrial appendage was preserved in 22 patients but not in 20. Blood samples were obtained before and after the operation for measurement of atrial natriuretic peptides. To evaluate the influence of atrial natriuretic peptides on the ability of the kidneys, we also measured body weight, fluid balance, and the doses of furosemide and dopamine administered after the operation. RESULTS: The restoration to sinus rhythm at 1 month after was comparable in the two groups. Plasma atrial natriuretic peptide levels significantly increased after the operation in patients in whom the right atrial appendage was preserved (1 day after: 23.4 +/- 17.8 vs 3 days after: 42.7 +/- 23.6 and 7 days after: 36.3 +/- 23.7 pg/mL, P <.05) but not in patients in whom the right atrial appendage was not preserved (1 day after: 20.0 +/- 19.6, 3 days after: 28.5 +/- 19.3, and 7 days after: 23.0 +/- 16.1 pg/mL). Furthermore, plasma atrial natriuretic peptide levels were significantly lower in patients in whom the right atrial appendage was not preserved than in patients in whom the right atrial appendage was preserved at 3 and 7 days after the operation. The fluid balance during the first 7 days of the postoperative period was comparable in the two groups, although the total dose of dopamine used in the same period was significantly smaller in patients in whom the right atrial appendage was preserved than in patients in whom the right atrial appendage was not preserved (155.3 +/- 119.0 vs 244.9 +/- 129.0 microg/kg, P <.05). CONCLUSIONS: The present study showed that preservation of the right atrial appendage lessens the decrease of plasma atrial natriuretic peptide levels after the maze procedure and that increased plasma atrial natriuretic peptides may improve the ability of the kidneys to excrete the fluid load after the operation.

Atrial Appendage↗
PubMed2000

Induction of apoptosis in mouse brain capillary endothelial cells by cyclosporin A and tacrolimus.

Although cyclosporin A and tacrolimus are used clinically as potent immunosuppressants, there have been reports of neurotoxicity and encephalopathy. A possible mechanism is that these drugs damage the blood-brain barrier (BBB), inducing dysfunction and increased permeability, and are then able to enter the brain. We studied the cytotoxicity of cyclosporin A and tacrolimus, focused on apoptosis induction, using an immortalized cell line established from BALB/c mouse cerebral microvessel endothelial cells (MBEC4). We found that these two drugs induced cell shrinkage, chromatin condensation and DNA fragmentation, which are characteristics of apoptosis. Our data suggest that the induction of apoptosis on the brain capillary endothelial cells may be at least partly involved in the occurrence of immunosuppressant-induced encephalopathy.

Animals↗
PubMed2000

A new approach for glomerular lesions: evaluation of scanning acoustic microscopy (SAM) for experimental glomerular disease in rats.

Most pathological evaluations using ordinary optical microscopy are usually qualitative and subjective. The beneficial properties of scanning acoustic microscopy (SAM) include not only observation of microstructure but also quantitative measurement of acoustic propagation speed, indicating the tissue elasticity. In this study, we examined the capability of SAM to evaluate pathological findings in glomeruli using anti-Thy.1 glomerulonephritis. Light microscopic observations of the glomeruli showed severe cell proliferation and mesangial matrix expansion at 10 days after induction of glomerulonephritis and, yet, to a lower extent at day 21 with onset of healing. C-mode scanning of SAM enabled imaging of glomerular structure compatible to findings of ordinary light microscopy. In addition, glomerular propagation speed in nephritic rats was significantly increased at day 10, and then decreased at day 21. These results indicate that SAM evaluation may be a new, useful technique for quantitative evaluation of proliferative glomerular lesions.

Animals↗
PubMed2000

Physical properties of the mitral valve tissue assessed by tissue sound speed in cardiac amyloidosis: relationship to the severity of mitral regurgitation.

Cardiac amyloidosis has been documented to show mitral regurgitation (MR) and a thickened mitral valve (MV) due to amyloid deposits. However, the changes in the physical properties of the thickened MV tissue in cardiac amyloidosis, which may be a causative factor of the MR, have not been described. Physical properties of the tissue, which are expressed by the elastic bulk modulus, can be evaluated by tissue sound speed. If biological tissue is assumed to be fluid-like, the tissue sound speed may be given by c= square root of K/rho, where c is the tissue sound speed, K is the elastic bulk modulus, and rho is the density. A reduction in tissue sound speed indicates a reduction in the elastic bulk modulus of the tissue, assuming that there is little change in rho. This suggests that the tissue is less elastic. The purpose of this study was to assess the physical properties of MV tissue by evaluating the sound speed of the MV tissue in cardiac amyloidosis. MV specimens were obtained at autopsy from 20 control adults without cardiovascular diseases and from 20 patients with cardiac amyloidosis. An acoustic microscope operating at 450 MHz was used to measure the tissue sound speed in the tip and basal portions of the MV tissue. The density of MV tissue was measured by microgravimetry. The severity of the MR had been evaluated by Doppler echocardiography before death, and it was compared with the tissue sound speed measured after death. In cardiac amyloidosis showing mild MR, the tissue sound speed of the MV in the tip portion (1605 +/- 19 m/s) and in the basal portion (1791 +/- 64 m/s) were lower than the corresponding values in control subjects (1637 +/- 42 m/s and 1851 +/- 62 m/s). However, these differences were not statistically significant. In cardiac amyloidosis showing moderate MR, the tissue sound speed of MV in the tip portion (1563 +/- 17 m/s) and in the basal portion (1654 +/- 59 m/s) were significantly lower than the corresponding values in the control subjects (p < 0.001) and the patients with mild MR (p < 0.05). No significant differences were observed in the density of MV tissue among the three groups. Therefore, the low value of the MV tissue sound speed in patients with cardiac amyloidosis indicated a reduced elastic bulk modulus, suggesting the less elasticity of the MV tissue. Furthermore, the patients with moderate MR demonstrated the greater reduction in the tissue sound speed than the patients with mild MR. The data suggest that the changes in physical properties of the MV tissue may be one of the causes of MR in cardiac amyloidosis.

Acoustics↗
PubMed2000

Evaluation of progression in nonrheumatic aortic valvular stenosis by scanning acoustic microscopy.

To investigate distributions of hardness and thickness in nonrheumatic aortic stenosis (AS), scanning acoustic microscopy was used. The acoustic propagation speed (APS: m/s) and thickness at three sites (tip, middle and base) of aortic valve were measured in 18 cusps from 7 surgical patients with AS (late lesion), 27 showing mild lesions from 9 autopsy cases (early lesion) and 18 healthy from 6 autopsy cases (healthy). These were measured in each layer of cusps: fibrosa (F), spongiosa (S) or ventricularis (V). In early lesions, an increase in APS preceded the thickening and distributed in the tip (1666 +/- 107), the three layers of the middle (F: 1782 +/- 121; S: 1590 +/- 38; V: 1636 +/- 59) and the fibrosa of the base (1736 +/- 203). In late lesions, APS of the tip and three layers of the base were markedly increased. Progressive nonrheumatic AS is characterized by increased hardness that precedes the thickening, and its distribution may be related to mechanical stress.

Adult↗
PubMed2000

Three minute, but not one minute, ischemia and nicorandil have a preconditioning effect in patients with coronary artery disease.

OBJECTIVES: This study focused on 1) the determination of the optimal preconditioning (PC) duration, and 2) the protective effect of nicorandil (NC), a hybrid nitrate with a KATP channel opening effect, during a percutaneous transluminal coronary angioplasty (PTCA) model in humans. BACKGROUND: The ischemic PC effect is induced in 180 s ischemia, but not in 120 s ischemia in rabbit hearts. However, the duration of ischemia that induces PC effect and the role of the KATP channel in the PC effect in humans are still unclear. METHODS: Forty-six patients with stable angina were randomly allocated to four groups: the duration of the first inflation as PC ischemia was 60 s in the PC60 group (n = 12), and 180 s in the PC180 group (n = 12). In the other groups, NC (80 microg/kg) was intravenously given for 1 min in the NC group (n = 12), and isosorbide dinitrate (ISDN) (40 microg/kg) was given in the ISDN group (n = 10). Five minutes after first inflation or drug administration, a second inflation was conducted for 120 s in each group. In the ECG, the lead with the largest shift in ST segment (deltaST max), and the sum of elevated ST levels in all leads (sigmaST) were determined. RESULTS: In the PC60 group, no significant difference was observed in either deltaST max or sigmaST between the first and second inflation. However, the second inflation in the PC180 group showed significantly lower levels of deltaST max and sigmaST compared with those of the first inflation. In the NC group, both deltaST max and sigmaST measured at 30 s and 60 s after balloon inflation were significantly lower than those of the first inflation in the PC60 and PC180 control groups. In the ISDN group, no significant difference was observed in deltaST max or sigmaST. CONCLUSION: In human PTCA models, a PC effect is observed in 180 s ischemia, but not in 60 s ischemia. A pharmacological PC effect is induced by NC, a KATP channel opener with a nitrate-like effect but not ISDN. This suggests that the opening of KATP channels plays an important role in the protecting effect of NC.

Angina Pectoris↗
PubMed2000

Production and clearance sites of two molecular forms of adrenomedullin in human plasma.

Human adrenomedullin (AM) precursor is converted to glycine-extended AM (AM-Gly), an inactive intermediate form of AM. Subsequently, AM-Gly is converted to active mature AM (AM-m) by enzymatic amidation. A recent study showed that two molecular forms of adrenomedullin (AM) are present in human plasma. In this study we investigated the production and clearance sites of two molecular forms of adrenomedullin in humans. We measured plasma levels of AM-m and AM-Total (T) (AM-m+AM-Gly) by immunoradiometric assay and calculated plasma levels of AM-Gly in blood samples taken from various sites during cardiac catheterization in patients with ischemic heart disease. Plasma AM-m levels were significantly lower in left-sided sites after passing through pulmonary circulation than in right-sided sites, whereas there were no significant differences in AM-Gly levels between left-sided sites and right-sided sites. These results suggest that AM-m produced in many organs is released into veins and that the main clearance sites of AM-m are the lungs. Considering that AM preferentially dilates pulmonary vessels rather than systemic vessels, a possible role of this peptide is suggested in the regulation of pulmonary vascular tonus.

Adrenomedullin↗
PubMed2000

Propiverine-induced Parkinsonism: a case report and a pharmacokinetic/pharmacodynamic study in mice.

PURPOSE: We present a case report of propiverine-induced Parkinsonism. We previously reported the induction of catalepsy by amiodarone, aprindine and procaine, which possess a diethylaminomethyl moiety and demonstrated selective blockade of dopamine D2 receptors by these drugs in mice. We hypothesized that drugs possessing a diethylaminomethyl structure may generally induce Parkinsonism and/or catalepsy. METHODS: Thus, we performed a study to examine whether oxybutynin, pentoxyverine and etafenone, as well as propiverine, induce catalepsy in mice. RESULTS: The intensity of drug-induced catalepsy was in the order: haloperidol > etafenone > pentoxyverine > propiverine > oxybutynin. In vivo occupancy of dopamine D1, D2 and mACh receptors in the striatum was also examined. The in vitro binding affinities to the D1, D2 and mACh receptors in the striatum synaptic membrane were within the ranges of 2.4-140 microM, 380-4,200 nM, and 1.2-2,800 nM, respectively. CONCLUSIONS: These results support the idea that any drug possessing a diethylaminomethyl moiety may contribute to the induction of catalepsy, possibly by occupying dopamine receptors.

Animals↗
PubMed2000

Parahisian radiofrequency catheter ablation in dogs: comparison of the above-valve and below-valve approaches.

In patients with an accessory pathway close to the His bundle, radiofrequency catheter ablation (RFCA) requires additional care to avoid damage to the normal conduction system. To assess differences between approaches from above or below the tricuspid valve (TV), we performed RFCA in 20 dogs (from above, group A, n=10; from below, group B, n=10). RF energy with temperature control at 60 degrees 60 seconds was administered at the site where a small His potential was recorded from the ablation catheter guided by fluoroscopy and transesophageal echocardiography (TEE) (in the latter six dogs). Before and after RFCA, electrophysiological testing was performed and histological findings were compared. An ablated lesion was created in 7 of 10 (2 of 2 guided by TEE) dogs in group A and 5 of 10 (3 of 4 TEE) dogs in group B. In group A, an ablated lesion involved the atrium and ventricle in the anterior site of His bundle, but the lesion was only in the ventricle in group B. An atrioventricular block (AVB) and severe damage to the penetrating bundle was observed in one dog of group A. A large hematoma on the TV was made in 2 dogs and the complete right bundle branch block (CRBBB) occurred in 3 dogs of group B. The approach from below the TV was safer than that from above the TV in parahisian RFCA, because it did not create an AVB, although it has a high incidence of CRBBB and associated technical difficulties.

Animals↗
PubMed2000

Effect of furanocoumarin derivatives in grapefruit juice on the uptake of vinblastine by Caco-2 cells and on the activity of cytochrome P450 3A4.

1. The presence of inhibitors of drug efflux transporters, such as P-glycoprotein (P-gp), in grapefruit juice (GFJ) was confirmed based on the uptake of [(3)H]-vinblastine (VBL) by Caco-2 cells. 2. The uptake of [(3)H]-VBL by Caco-2 cells was significantly increased by the ethyl acetate extract of GFJ as well as by cyclosporin A. The extract was separated on a Cosmosil column and the eluate with 60% methanol increased [(3)H]-VBL uptake, while the activity to inhibit CYP3A4 was greatest in the 70 and 80% eluates. 3. These results show that the major inhibitor of efflux transport of VBL is different from that of CYP3A4. 4. Further separation of the 60% methanol eluate afforded dihydroxybergamottin (DHBG). Both ethyl acetate extract of GFJ and DHBG increased steady-state [(3)H]-VBL uptake by LLC-GA5-COL300 cells. Besides DHBG, other furanocoumarins contained in GFJ, such as bergamottin, FC726, bergaptol and bergapten, increased the steady-state uptake of [(3)H]-VBL by Caco-2 cells. 5. The order of inhibitory potency of these compounds was FC726>DHBG>bergamottin>bergapten>bergaptol . While, the IC(50) values for inhibition of CYP3A4 were 0.075, 0.45, 1.0, 1.0 and >20 microM, respectively. Bergaptol specifically inhibited VBL efflux. 6. DHBG was thus identified as a candidate for inhibitors of VBL transport, together with other furanocoumarins. Moreover, partly involvement of the P-gp inhibition was suggested. 7. Therefore, the inhibition of efflux transport of drugs as well as of drug metabolism by CYP3A4 could be an important cause of drug-GFJ interaction.

3-O-Methylglucose↗
PubMed2000

Effect of neutral endopeptidase inhibitor on endogenous atrial natriuretic peptide as a paracrine factor in cultured cardiac fibroblasts.

1. Cardiac remodelling is a fundamental response to hypertension, myocardial infarction and chronic heart failure, and involves cardiac fibroblast proliferation and production of extracellular matrix components such as collagen. The present study was performed to examine the role of endogenous atrial natriuretic peptide (ANP) as a possible paracrine factor for cardiac fibroblasts, and to examine the effects of three neutral endopeptidase (NEP) inhibitors, thiorphan, phosphoramidon and ONO-BB-039-02 (ONO-BB) on endogenous ANP-induced changes in collagen synthesis by cultured neonatal rat cardiac fibroblasts. 2. Each NEP inhibitor singly had no significant effect on collagen synthesis by cardiac fibroblasts, except for maximum concentration (10(-3) M) of thiorphan. 3. Exogenous ANP inhibited collagen synthesis in a concentration-dependent manner (10(-8) - 10(-6) M). Thiorphan (10(-4) and 10(-3) M) and phosphoramidon (10(-5) and 10(-4) M) enhanced the ANP (10(-7) M)-induced decrease in collagen synthesis. ONO-BB (10(-5) and 10(-4) M) slightly enhanced the ANP-induced decrease in collagen synthesis. 4. Myocyte-conditioned medium (MC-CM), as well as exogenous ANP, inhibited collagen synthesis dose-dependently. The decrease in collagen synthesis at 100% MC-CM was augmented by thiorphan (10(-3) M), phosphoramidon (10(-4) M) and ONO-BB (10(-4) M). 5. HS-142-1, a natriuretic peptide receptor antagonist, significantly reduced the MC-CM plus thiorphan- and MC-CM plus ONO-BB-induced decrease in collagen synthesis, by 92 and 62%, respectively and showed a tendency to attenuate the MC-CM plus phosphoramidon-induced decrease in collagen synthesis by 40%. 6. Our observations suggested that endogenous ANP released from cardiomyocytes inhibited collagen synthesis as a paracrine factor and that NEP inhibitors enhanced the activity of this peptide in cardiac fibroblasts.

Animals↗
PubMed2000

Pharmacokinetic analysis of felodipine-grapefruit juice interaction based on an irreversible enzyme inhibition model.

UNLABELLED: Aims Ingestion of grapefruit juice (GFJ) alters the pharmacokinetics of various orally administered drugs. Quantitative evaluation of this GFJ-drug interaction is required for the proper clinical management of patients. Methods Using felodipine as a model drug, we constructed a pharmacokinetic model based on irreversible inhibition of intestinal cytochrome P450 3A4 (CYP3A4) by GFJ. We fitted previously published data [5, 6] for felodipine ER (extended release formulation) to the ratio of CLGI,int before and after grapefruit juice ingestion by nonlinear least-squares regression analysis to estimate the reaction rate constant between GFJ and CYP3A4 (K) and the elimination rate constant of CYP3A4 (k ). RESULTS: The model gave a turnover rate of CYP3A4 of 0.0849 h-1, corresponding to a half-life of 8.16 h, in agreement with reported values. The AUC-time profiles of felodipine ER in the case of different amounts and schedules of GFJ ingestion were simulated using the parameter values estimated from the model. CONCLUSIONS: The modelling leads to the important conclusion that GFJ-felodipine interaction increases with increasing frequency and amount of GFJ ingestion, and that an interval of 2-3 days between GFJ intake and felodipine administration is necessary if GFJ-felodipine interaction is to be avoided.

Adult↗
PubMed2000

Hydrogen peroxide augments eosinophil adhesion via beta2 integrin.

During eosinophil (EOS) accumulation at sites of allergic inflammation, an initial step is the binding of EOS to adhesion molecules expressed on vascular endothelial cells (EC). We have previously observed that adhesion of peripheral blood EOS to recombinant human vascular cell adhesion molecule-1 (rh-VCAM-1) stimulates the respiratory burst of EOS. Although the biological consequence of this activation remains to be elucidated, reactive oxygen species such as hydrogen peroxide (H2O2) may modify the adhesive property of EOS. In the present study, we examined whether H2O2 modifies the adhesive property of EOS. EOS were isolated from the peripheral blood of healthy subjects. Adhesion of the EOS to paraformaldehyde-fixed human umbilical vein EC (HUVEC), stimulated or not stimulated with tumour necrosis factor-alpha (TNF-alpha; 100 pM for 24 hr), was examined in the presence or absence of H2O2. H2O2 significantly enhanced adhesion of EOS to both resting and TNF-alpha-stimulated fixed HUVEC (P < 0.01, respectively). Such enhancing effects were inhibited by anti-beta2 integrin antibody or anti-CD11b antibody, but not by anti-CD11a or anti-alpha4 integrin antibody. H2O2 also enhanced EOS adhesion to rh-intracellular cell adhesion molecule-1 (ICAM-1) but not to rh-VCAM-1. Finally, H2O2 enhanced the expression of both CD11b and CD18 on EOS. These results indicate that H2O2 directly augments the adhesive property of EOS through beta2 integrin.

Adult↗