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Biomedical subjects

H Kasanuki

Publications and source records attributed to H Kasanuki.

At least 73 records · Page 4Linked to original sources
PubMed1998

Evaluation of regional cardiac sympathetic innervation in congenital long QT syndrome using 123I-MIBG scintigraphy.

The aim of this study was to determine whether sympathetic imbalance in congenital long QT syndrome (LQTS) can be identified by cardiac sympathetic neuronal dysinnervation. 123I-metaiodobenzylguanidine (MIBG) is a tracer of the norepinephrine analogue which reflects the regional innervation and norepinephrine kinetics in cardiac sympathetic nerves. Sixteen patients with LQTS, who were members of 12 families, and 7 normal controls underwent MIBG scintigraphy. Myocardial SPET and planar images were obtained 15 min and 4 h after the injection of MIBG in each patient. The relative regional uptake (RRU) and regional washout rate (rWR) of MIBG at 4 h in each of nine regions were compared with those in the control group. The heat-to-mediastinum ratio (H/M) and global washout rate (GWR) were also calculated. The RRU, rWR, H/M and GWR showed no significant difference between LQTS patients and normal controls. Furthermore, the RRU in 96% of all regions in LQTS was within the mean +/- 2 standard deviations of that in the control group. Patients with LQTS have normal cardiac sympathetic innervation, as assessed by MIBG. The sympathetic imbalance hypothesis is unlikely to be attributed to an abnormal distribution and different regional norepinephrine kinetics of cardiac sympathetic nerves.

3-Iodobenzylguanidine↗
PubMed1998

Familial sick sinus syndrome with atrioventricular conduction disturbance.

A family with sick sinus syndrome is presented: a mother and her 2 daughters affected with sinus node dysfunction. Electrophysiological studies revealed abnormal atrioventricular conduction in the 2 daughters. All 3 individuals were implanted with a permanent pacemaker to relieve their symptoms. Endomyocardial biopsy from the right ventricle of one daughter showed disarrangement, degeneration, myocyte necrosis and interstitial fibrosis suggestive of myocardial disease.

Adult↗
PubMed1998

Primary cardiac angiosarcoma of the right atrium undiagnosed by transvenous endocardial tumor biopsy.

A 50-year-old man was admitted with acute pericarditis. Echocardiography demonstrated a large mass on the right atrial free wall along with a pericardial effusion. We performed transvenous biopsy of this mass under transesophageal echocardiographic guidance. Though the biotome obtained the mass, the pathological findings were of organized thrombus. Two weeks later, a new precordial mass appeared around the left third rib and was suspected to be a metastasis. Incisional biopsy of this mass gave the diagnosis of angiosarcoma.

Acute Disease↗
PubMed1998

[The effect of MS-551 on two VT/Vf patients in CABG: a case report].

Uncontrollable arrhythmia is one of the causes of operative death in CABG. We report two cases of successful treatment of recurrent VT/Vf in CABG operation by MS-551. One case was a 72-year-old male, who had unstable angina and OMI with left ventricular dysfunction (LVEF 24%). After weaning from CPB, the rhythm turned into VT/Vf suddenly. Lidocaine and verapamil were not effective. VT/Vf recurred over the over. The another case was a 52-year-old male, who had OMI and effort angina. He became myocardial infarction during operation. VT/Vf occurred after the weaning from CPB. Lidocaine and amiodarone were of no effect on his VT/Vf. In both cases, intravenous injection of MS-551 promptly stopped VT/Vf. Use of MS-551 was limited mainly on DCM patients. But other antiarrhythmic agents were ineffective on these cases. We have had to continue support circulation for a long time without MS-551. As MS-551 is being used as a trial on medically followed patients, it was unknown how effective clinically on the acute myocardial infarction. In this regard, our cases may suggest a positive answer to that.

Aged↗
PubMed1998

[Cardiac sympathetic denervation after aortic surgery in a patient with thoracic dissecting aneurysm: a case report].

We experienced a case of a 60 year-old man with cardiac sympathetic denervation after aortic graft replacement of ascending aorta for a dissecting aneurysm (Debakey type II). Fourteen years after pheochromocytomectomy (paraganglioma), the patient developed a severe chest pain, and admitted to the hospital for the diagnosis of dissecting aneurysm. CT scan with contrast enhancement revealed thrombosed dissecting aneurysm in the region of ascending aorta to aortic arch. Graft replacement was undergone on the same day. 123I-MIBG imaging 20 days after the operation showed severely attenuated myocardial uptake (heart to mediastinum ratio 1.19), although the MIBG imaging before the operation showed normal myocardial uptake (heart to mediastinum ratio 1.55). Heart rate variability analysis in Holter ECG showed that the power of the low frequency (LF), that of the high frequency (HF) and L/H ratio were severely decreased. MIBG and heart rate variability analysis indicated that cardiac sympathetic and parasympathetic nerve were denervated. This is the first report of cardiac sympathetic denervation after aortic vascular surgery. Clinical significance of cardiac sympathetic denervation after aortic vascular surgery is uncertain, and further investigation will be required.

3-Iodobenzylguanidine↗
PubMed1998

[Catheter intervention for adult congenital heart diseases].

The efficacy of catheter intervention for adult congenital heart diseases was evaluated in 27 patients aged 20 to 52 years (mean age at catheterization 25 +/- 7 years) from 1986 to 1996. Four patients had pulmonary valve stenosis, four had aortic valve stenosis, three had coarctation of the aorta, 10 had pulmonary artery stenosis, four had cyanotic heart diseases and aorto-pulmonary collateral arteries, one had patent ductus arteriosus, and one had cyanotic heart disease and stenotic Blalock-Taussig shunt. Balloon dilation was successful in all patients with pulmonary valve stenosis, and follow-up evaluation (1-8 years) showed no restenosis in any patients. Balloon dilation was successful in all patients with aortic valve stenosis, and follow-up evaluation (0.5-5 years) showed transvalvular pressure gradient < 50 mmHg. Stenosis was relieved successfully in all patients with coarctation of the aorta, and follow-up evaluation showed no restenosis. Balloon dilation was successful in eight of 13 locations (62%) in patients with pulmonary artery stenosis. Coil embolization was successful in all patients with cyanotic heart diseases and aortopulmonary collateral arteries. In a patient with patent ductus arteriosus, two coils were placed in the ductus arteriosus but were retrieved because hemolysis was observed after the embolization. These data indicate that catheter intervention in young adults with congenital heart diseases is as effective as in children.

Adult↗
PubMed1998

[Treatment of cardiovascular Behçet's disease: a problem with valve replacement].

The treatment of aortic regurgitation (AR) caused by cardiovascular Behçet's disease was retrospectively analyzed in five patients with Behçet's disease complicated by moderate or severe AR (four men and one woman, with a mean age of 47 +/- 5.8 years; complete 1, incomplete 2, and suspected 2). The preoperative left ventricular end-diastolic diameter was larger than 60 mm (mean: 74 mm) in all patients, and the left ventricular fractional shortening was less than 0.28 in three patients. Aortic valve replacement (AVR) was performed in four patients, but perivalvular regurgitation developed in all patients after a mean of 5.4 +/- 1.2 months (range: 0.6-10 months) following surgery, causing the death of three patients. One patient (grade III) who did not undergo operation showed gradually increasing end-diastolic diameter, but he is still being followed up medically due to the poor outcome of surgery. Because of inflammation-induced tissue fragility, AVR was associated with postoperative perivalvular regurgitation and suture breakdown, resulting in an extremely poor outcome. Thus, AVR was considered best avoided even if Behçet's disease was complicated with moderate or severe AR.

Adult↗
PubMed1997

Idiopathic ventricular fibrillation induced with vagal activity in patients without obvious heart disease.

BACKGROUND: Recently, idiopathic ventricular fibrillation (VF) has gained much attention. Although several subgroups have been described, its pathogenesis, mechanism, treatment, and prognosis remain unknown. METHODS AND RESULTS: We studied six cases of idiopathic VF with transient late r' waves and ST elevation (late r'/ST elevation) in leads V1 through V3. Late r'/ST elevation was augmented before and after VF episodes. Signal-averaged ECGs showed late potentials even when no late r'/ST elevation occurred. During late r', a conduction delay was observed by use of body-surface maps at the anterior wall and outflow tract of the right ventricle without inhomogeneity of the repolarization phase. There was a decrease or total disappearance of late r'/ST elevation with isoproterenol, atropine, and exercise stress testing and induction or exacerbation with propranolol, edrophonium, and hyperventilation. VF was induced by programmed electrical stimulation in all cases but two, in which it was induced only after edrophonium injection. In two cases, VF was exacerbated by propranolol, and in all cases, it was uninducible with isoproterenol. Heart rate spectral analysis just before VF episodes showed a sudden rise in vagal activity in two cases. As the VF mechanism, a conduction delay exists at the anterior wall and outflow tract of the right ventricle that is possibly exacerbated by an abrupt rise in vagal activity, inducing random reentry that results in VF. Class I antiarrhythmic agents and beta-blockers were ineffective for this VF. All subjects required implantable cardioverter-defibrillators. CONCLUSIONS: We propose this VF associated with late r'/ST elevation in the precordial leads and influenced by vagal activity as a new possible mechanism of idiopathic VF.

Adult↗
PubMed1997

ATP-activated cationic current in rabbit sino-atrial node cells.

The electrophysiological effect of extracellular ATP was investigated in voltage-clamped single cells from the rabbit sino-atrial node. External 0.5 mM ATP consistently activated a time-independent, weakly inwardly rectifying current (2.26 +/- 0.14 pA/pF at -100 mV, n = 23). This external ATP-activated current increased in a dose-dependent manner over the concentration range 0.01 to 1 mM ATP. However, non-hydrolysable ATP analogs (a, beta-methylene ATP and beta,r-methylene ATP) failed to activate this current. Moreover, adenosine, adenosine monophosphate and adenosine diphosphate were all ineffective in eliciting the ATP-activated current over the concentration range 0.5 to 1 mM, suggesting that it is regulated via the P2-purinoreceptor. The permeability sequence for the ATP-activated current among different cations (determined from reversal potential measurements) was 1.09: 1: 1: 0.24: 0.22 for K+, Na+, Cs+, Tris and N-methyl-D-glucamine. The current component was not affected by substitution of external Cl- by aspartate or by the application of a stilbene-derivative Cl- channel blocker. Thus, the ATP-activated current in rabbit sino-atrial node cells was non-selective for monovalent cations, and could be carried by large molecular ions, such as N-methyl-D-glucamine or Tris. We suggest that it might make some contribution to the chronotropic effects seen on release of transmitters from autonomic nerve endings in the heart.

Adenosine↗
PubMed1997

Functional activity of the CFTR Cl- channel in human myocardium.

The cyclic AMP (cAMP)-dependent chloride channel in the heart has been identified in various species as the cystic fibrosis transmembrane conductance regulator (CFTR). Although functional expression of the channel in the human atrium has been reported, we could not induce any cAMP-dependent chloride conductance in the atrial cells even with maximal cAMP stimulation, whereas the conductance could be induced in rabbit ventricular cells. To clarify the discrepancy between the results, we examined the level of CFTR mRNA expression in both conductance-positive (human colonic epithelium and rabbit ventricle) and -negative (human atrium) tissues. Total RNA samples prepared from these tissues were subjected to the reverse transcription-polymerase chain reaction (RT-PCR). While CFTR transcripts were amplified from the conductance-positive samples, no amplified products could be detected from the conductance-negative sample. A nested PCR performed on the RT-PCR products of the conductance-negative sample resulted in successful amplification of the transcripts, indicating that the level of the CFTR mRNA expression in human atrium is extremely low compared with that in colonic epithelium and rabbit ventricle. The same molecular results were observed in human ventricular tissues. A nucleotide sequencing of the amplified transcripts showed that exon 5 of the CFTR gene was not alternatively spliced in human atrium and ventricle, and both the exon 5 spliced and unspliced isoforms were expressed in rabbit ventricle, unlike the findings of previous reports. Our data suggest that the amount of CFTR expressed in human myocardium might be physiologically insufficient to activate detectable cAMP-dependent chloride conductance.

Adolescent↗
PubMed1997

Disopyramide improves the balance between myocardial oxygen supply and demand in patients with hypertrophic obstructive cardiomyopathy.

We evaluated the effects of disopyramide in terms of the balance between myocardial oxygen supply and demand in patients with hypertrophic obstructive cardiomyopathy (HOCM). The myocardial oxygen supply was evaluated by measuring coronary flow velocity and the myocardial oxygen demand was assessed by the pressure-volume area (PVA). The time velocity integral of coronary flow did not change significantly (20 +/- 6 to 21 +/- 8 cm), but the peak left ventricular pressure and left ventricular external work decreased significantly (206 +/- 44 to 157 +/- 37 mmHg, P < 0.001; 1.09 +/- 0.33 to 0.80 +/- 0.23 J/beat, P < 0.001) after disopyramide administration. From theoretical analysis using these data, we concluded that disopyramide improves the myocardial oxygen supply-demand balance in patients with HOCM.

Adult↗
PubMed1997

Cardiac memory in patients with intermittent Wolff-Parkinson-White syndrome.

This study used body surface mapping to evaluate the ventricular repolarization process in the absence of delta waves in 13 patients with the intermittent Wolff-Parkinson-White (WPW) syndrome. The findings were compared with data from 30 normal individuals and 50 patients with the overt WPW syndrome. The QRST isointegral maps of patients with the overt WPW syndrome exhibited abnormal areas and the QRST departure maps showed a peculiar distribution to each accessory pathway site. The QRST isointegral map exhibited abnormal areas in 11 of the 13 cases (85%) of the intermittent WPW syndrome in the absence of delta waves. In 8 of these 11 cases (73%), the distribution of the departure map resembled that in the overt WPW syndrome. These findings suggest that abnormal ventricular repolarization due to cardiac memory is present in patients with the intermittent WPW syndrome even in the absence of delta waves.

Adolescent↗
PubMed1997

Contribution of phosphodiesterase isozymes to the regulation of the L-type calcium current in human cardiac myocytes.

1. To determine the contribution of the various phosphodiesterase (PDE) isozymes to the regulation of the L-type calcium current (ICa(L)) in the human myocardium, we investigated the effect of selective and non-selective PDE inhibitors on ICa(L) in single human atrial cells by use of the whole-cell patch-clamp method. We repeated some experiments in rabbit atrial myocytes, to make a species comparison. 2. In human atrial cells, 100 microM pimobendan increased ICa(L) (evoked by depolarization to +10 mV from a holding potential of -40 mV) by 250.4 +/- 45.0% (n = 15), with the concentration for half-maximal stimulation (EC50) being 1.13 microM. ICa(L) was increased by 100 microM UD-CG 212 by 174.5 +/- 30.2% (n = 10) with an EC50 value of 1.78 microM in human atrial cells. These two agents inhibit PDE III selectively. 3. A selective PDE IV inhibitor, rolipram (1-100 microM), did not itself affect ICa(L) in human atrial cells. However, 100 microM rolipram significantly enhanced the effect of 100 microM UD-CG 212 on ICa(L) (increase with UD-CG 212 alone, 167.9 +/- 33.9, n = 5; increase with the two agents together, 270.0 +/- 52.2%; n = 5, P < 0.05). Rolipram also enhanced isoprenaline (5 nM)-stimulated ICa(L) by 52.9 +/- 9.3% (n = 5) in human atrial cells. 4. In rabbit atrial cells, ICa(L) at +10 mV was increased by 22.1 +/- 9.0% by UD-CG 212 (n = 10) and by 67.4 +/- 12.0% (n = 10) by pimobendan (each at 100 microM). These values were significantly lower than those obtained in human atrial cells (P < 0.0001). Rolipram (1-100 microM) did not itself affect ICa(L) in rabbit atrial cells. However, ICa(L) was increased by 215.7 +/- 65.2% (n = 10) by the combination of 100 microM UD-CG 212 and 100 microM rolipram. This value was almost 10 times larger than that obtained for the effect of 100 microM UD-CG 212 alone. 5. These results imply a species difference: in the human atrium, the PDE III isoform seems dominant, whereas PDE IV may be more important in the rabbit atrium for regulating ICa(L). However, PDE IV might contribute significantly to the regulation of intracellular cyclic AMP in human myocardium when PDE III is already inhibited or when the myocardium is under beta-adrenoceptor-mediated stimulation.

1-Methyl-3-isobutylxanthine↗
PubMed1997

Influence of early coronary reperfusion on QT interval dispersion after acute myocardial infarction.

We studied the influence of early coronary reperfusion on QT interval dispersion in patients with acute myocardial infarction (MI). There were 54 males and 18 females with a mean age of 60 +/- 10 years. Of the 51 patients with recanalization of the infarct related vessel in the recovery phase, 28 (group A) had early coronary reperfusion (5.5 +/- 2.7 hours), 23 other patients (group B) were not confirmed with early coronary reperfusion. Twenty-one patients (group C) did not undergo recanalization of the infarct related vessel in the recovery phase. Corrected QT (QTc) maximum, QTc minimum, and QTc dispersion calculated as the difference between the maximum and minimum QTc intervals, were compared among these three groups at both acute and recovery phase. At the acute phase after MI, there were no significant differences in the QTc maximum, QTc minimum, QT dispersion, and QTc dispersion among these three groups. At the recovery phase after MI, there were also no significant differences in the QTc maximum and QTc minimum. However, there were significant differences in the QT dispersion (0.035 +/- 0.010 in group A, 0.049 +/- 0.015 in group B, and 0.061 +/- 0.031 s in group C, respectively; P = 0.0001), and QTc dispersion (0.038 +/- 0.012 in group A, 0.050 +/- 0.015 in group B, and 0.063 +/- 0.032 s in group C, respectively; P = 0.0003) among the three groups. Comparison of QTc dispersion between acute and recovery phase revealed significant reduction from acute to recovery phase in group A. The number of premature ventricular contraction was lower in group A and B than group C. In summary, early coronary reperfusion may reduce electrophysiological instability by reducing QT dispersion in the recovery phase after acute MI.

Cardiac Catheterization↗
PubMed1997

The role of cadherin-catenin-cytoskeleton complex in angiogenesis: antisense oligonucleotide of plakoglobin promotes angiogenesis in vitro, and protein kinase C (PKC) enhances angiogenesis through the plakoglobin signaling pathway.

Angiogenesis plays an important role in various diseases and conditions such as malignant tumor, wound healing, and atherosclerosis. Since cell-to-cell adhesion may play a key role in angiogenesis, we investigated the effect of the cadherin-catenin-cytoskeleton complex on angiogenesis in human umbilical vein endothelial cells (HUVECs). Immunofluorescence staining revealed that alpha-catenin, beta-catenin, and plakoglobin were concentrated at cell-cell contacts in HUVECs. Antisense oligonucleotide (AS-oligo), complementary to the region of human plakoglobin was dissolved in saline and applied to the media at 1 mM every 12 h for 4 days, and sense oligonucleotide (S-oligo) was used as control. HUVEC migration from an injury line was enhanced by AS-oligo. Interestingly, HUVECs migrated in line with S-oligo, and in a scattered fashion with AS-oligo. Tube formation on Matrigel occurred earlier with AS-oligo than with S-oligo. These findings indicate that plakoglobin inhibited HUVEC migration and tube formation (angiogenesis) by regulating cell-cell adhesion.

Cadherins↗
PubMed1997

Recent therapeutic strategy for sustained ventricular tachycardia in Japan.

We investigated the therapeutic principles and strategies to treat sustained ventricular tachycardia (SVT) as five leading medical institutions in the Tokyo area and summarized the present situation of SVT treatment in Japan. Catheter ablation (ABL) has been almost established to be effective in idiopathic ventricular tachycardia (IVT) and was used as the last treatment in 60.3% of IVTs in this series. ABL may be the first option of therapy for IVT. In patients with SVT who have underlying cardiac diseases, the last treatment was class I drugs in 8.3%, class III drugs in 34.3%, combination drug therapy in 24.0%, ABL in 33.3%, surgical therapy (SUR) in 7.3%, and implantable cardioverter defibrillator (ICD) in 12.5% (nonpharmacological therapy in combination with other therapy). The use of class I drugs was not common, whereas class III drugs were used more frequently in patients with a low left ventricular ejection fraction. In some patients with reduced cardiac function, a combination of class III drugs and non-pharmacological therapy is appropriate.

Adult↗