Biomedical subjects

Kenji Iino

Publications and source records attributed to Kenji Iino.

14 recordsLinked to original sources

PubMed2006

Upregulation of TRPC1 in the development of cardiac hypertrophy.

The importance of Ca(2+) entry in the cardiac hypertrophic response is well documented, but the actual Ca(2+) entry channels remain unknown. Transient receptor potential (TRP) proteins are thought to form either homo- or heteromeric Ca(2+) entry channels that are involved in the proliferation and differentiation of various cells. The purpose of this study was to explore the potential involvement of TRP channels in the development of cardiac hypertrophy. The mRNA and protein expression of several TRP channel subunits were evaluated using hearts from abdominal aortic-banded (AAB) rats. Although TRPs C1, C3, C5, and C6 were constitutively expressed, only TRPC1 expression was significantly increased in the hearts of AAB rats compared to sham-operated rats. Using primary cultures of neonatal rat cardiomyocytes, we detected increases in the expression of TRPC1, brain natriuretic peptide (BNP), and atrial natriuretic factor (ANF), as well as increases in store-operated Ca(2+) entry (SOCE) and cell surface area, following endothelin-1 (ET-1) treatment. Silencing of the TRPC1 gene via small interfering RNA (siRNA) attenuated SOCE and prevented ET-1-, angiotensin-II (AT II)-, and phenylephrine (PE)-induced cardiac hypertrophy. In HEK 293T cells, overexpression of TRPC1 augmented SOCE, leading to an increase in nuclear factor of activated T cells (NFAT) promoter activity, while co-transfection with dominant-negative forms of TRPC1 suppressed it. In conclusion, TRPC1 functions in Ca(2+) influx, and its upregulation is involved in the development of cardiac hypertrophy; moreover, it plays an important role in the regulation of the signaling pathways that govern cardiac hypertrophy. These findings establish TRPC1 as a functionally important regulator of cardiac hypertrophy.

Animals↗

PubMed2006

Regulatory role of neuron-restrictive silencing factor in expression of TRPC1.

Neuron-restrictive silencer factor (NRSF) binds its consensus element to repress the transcription of various genes. The dominant-negative form (dnNRSF) has a hypertrophic effect on cardiogenesis through an unidentified mechanism. We examined the involvement of transient receptor potential (TRP) channel proteins, using transgenic mice overexpressing dnNRSF (dnNRSF mice). Electrophoretic mobility-shift assays revealed an interaction between NRSF and a neuron-restrictive silencer element-like sequence in intron 4 of TRPC1 genomic DNA. According to RT-PCR and Western analyses, TRPC1 was up-regulated in dnNRSF mouse heart. Transient overexpression of TRPC1 in HEK 293T cells increased the activity of the nuclear factor in activated T cells (NFAT) promoter and stimulated store-operated Ca(2+) channel (SOCC)-mediated Ca(2+) entry. Transfection of TRPC1 into primary cardiomyocytes increased NFAT activity, indicating a major role for TRPC1 in NFAT activation. Our findings strongly suggest that NRSF regulates TRP1 gene expression and causes changes in the levels of calcium entry through SOCCs.

Animals↗

PubMed2006

Biventricular pacing 18 months after Batista operation.

We conducted biventricular pacing in a patient with dilated cardiomyopathy and complete left bundle branch block who had recurrent heart failure and mitral valve regurgitation 18 months after partial left ventriculectomy and mitral valve repair. An epicardial lead was fixed on the left ventricular free wall surgically through a thoracotomy, and the other two leads were implanted transvenously. Biventricular pacing restored contractile synchrony and led to more efficient left ventricular contraction and reductions in mitral regurgitation. Biventricular pacing may produce beneficial effects for patients with the recurrent intractable heart failure associated with cardiomyopathy and complete left bundle branch block after partial left ventriculectomy.

Bundle-Branch Block↗

PubMed2006

Successful coronary revascularization using the PAS-Port system in a patient with Takayasu's arteritis and Behcet's disease.

Coronary artery disease is rare in patients with Takayasu's arteritis or Behcet's disease. We report the case of a patient with concomitant Takayasu's arteritis and Behcet's disease who had angina pectoris develop due to severe narrowing of the left main coronary artery. The patient underwent revascularization with saphenous vein grafts with the assistance of the PAS-Port Proximal Anastomosis System (Cardica, Inc, Redwood City, CA). In conclusion, the PAS-Port Proximal Anastomosis System seems to be a safe and effective method of facilitating revascularization, particularly when severe calcification of the ascending aorta precludes cross-clamping during off-pump coronary artery bypass grafting.

Anastomosis, Surgical↗

PubMed2006

[Use of angiotensin converting enzyme inhibitors and angiotensin receptor blockers in patients with acute coronary syndrome].

Renin-angiotensin system is well known that it plays an important role in the initiation and amplification of atherosclerosis that lead to cardiovascular disease. Angiotensin II is deeply involved in vasoconstriction, oxidative stress, inflammation, thrombosis, vascular remodeling, and sympathetic nerve activity. Many studies have documented the favorable effects of angiotensin converting enzyme inhibitor(ACE-I) and angiotensin receptor blocker(ARB) on cardiovascular disease in basic and clinical trials. Now accumulated evidences suggest ACE-I and ARB potentially prevent coronary plaque rapture, thrombosis and myocardial remodeling with acute coronary syndrome (ACS). ACS is occurred from plaque rupture on mild to moderate coronary atherosclerosis. Therefore, on treatment of ACS, it is important to prevent the plaque rupture and thrombosis by pharmacological intervention with ACE-I and ARB than coronary artery intervention which is down stream therapy for coronary artery stenosis.

Angina, Unstable↗

PubMed2005

Extended resection of mediastinal undifferentiated carcinoma after chemosensitivity test-guided induction treatment: report of a case.

We performed extended resection of primary mediastinal undifferentiated carcinoma, together with the superior vena cava and the upper lobe of the right lung, after effective induction chemoradiation therapy based on the results of a chemosensitivity test. Pathological examination of the resected specimen revealed that almost all of the tumor cells had died. The patient received adjuvant chemotherapy and has remained free from disease progression for 27 months since his operation. Our experience supports the effectiveness of an aggressive approach, in the form of chemosensitivity test-guided induction therapy, to treat this high-grade malignant disease, despite the risk of cancer dissemination.

Carcinoma↗

PubMed2005

Intramyocardial foreign body: sewing needle with the uncommon clinical feature of constrictive pericarditis.

A rare case of intracardiac injury with a sewing needle causing constrictive pericarditis is reported. A 72-year-old woman was admitted with edema of the face and legs. A chest radiogram showed a needle-shaped metallic image overlying the cardiac silhouette. Computed tomography revealed the needle was located in the left ventricular myocardium, and also showed a thickened pericardium. Surgical removal of the needle and pericardectomy were performed simultaneously.

Aged↗

PubMed2004

Radionuclide study of mid-term left ventricular function after endoventricular circular patch plasty.

OBJECTIVE: Although the early result of endoventricular circular patch plasty (EVCPP) has been reported, few are seen about the long-term results. We studied left ventricular (LV) function in the early and mid-term periods after EVCPP with electrocardiographic-gated single photon emission computed tomography (Gated SPECT). METHODS: Consecutive 14 patients with LV asynergy after myocardial infarction, who had the EVCPP procedure, were studied by Gated SPECT. Mean age of patients was 67+/-10 years. Gated SPECT images were obtained and LV end-diastolic volume index (EDVI), LV end-systolic volume index (ESVI) and ejection fraction (EF) were studied with QGS(+) program. Gated SPECT study was performed before surgery, early (23 days) and mid-term periods (32 months) after surgery. RESULTS: EDVI changed significantly from preoperative value to early postoperative value (107+/-39 to 72+/-37 ml/m(2), P < 0.01). There was no significant difference between early and mid-term postoperative values. ESVI also changed significantly from preoperative value to early postoperative value, and from early value to mid-term postoperative value (78+/-37 to 51+/-34 to 47+/-35 ml/m(2), P < 0.05, respectively). EF increased significantly from preoperative value to early postoperative value, and from early value to mid-term postoperative value (30+/-10 to 35+/-13 to 45+/-18%, P < 0.05, respectively). CONCLUSIONS: Direct influence of EVCPP brought significant improvement of LV function in early period. Further decrease of ESVI and increase of EF were noticed from early period to mid-term period. This result suggest that the effect of EVCPP sustains long and yields reverse LV remodeling.

Aged↗

PubMed2003

TNF-alpha rapidly antagonizes the beta-adrenergic responses of the chloride current in guinea-pig ventricular myocytes.

The purpose of this study was to test the hypothesis that tumor necrosis factor-alpha (TNF-alpha) rapidly antagonizes the beta-adrenergic responses of the chloride current and to clarify the intracellular mechanisms responsible for the anti-adrenergic action. The whole-cell patch-clamp technique was used to monitor the anti-adrenergic effects of TNF-alpha on the cAMP-dependent chloride current (I(Cl)) recorded from isolated guinea-pig ventricular myocytes. Ramp pulses (+/-120 mV; dv/dt = +/-0.4 V/s) were applied from the holding potential of -40 mV. TNF-alpha rapidly (<15 min) inhibited the isoproterenol (Iso, 0.1 micromol/L)-induced I(Cl) in a concentration-dependent manner (30-1,000 U/ml, IC (50) = 144 U/ml, n=30). The inhibitory action of TNF-alpha was also observed when I(Cl) had been previously stimulated by 1 micromol/L forskolin (n=5). Prior exposure of myocytes to 5 microg/ml pertussis toxin (PTX) hardly affected the anti-adrenergic action of TNF-alpha (n=4). However, when I(Cl) was induced by both 8-bromo-cAMP (100 micromol/L) and isobutylmethylxanthine (0.1 mmol/L), TNF-alpha (1,000 U/ml) failed to decrease I(Cl) amplitude (n=5). Prior exposure of myocytes to 5 mg/ml pertussis toxin (PTX) hardly affected the anti-adrenergic action of TNF-alpha (n=4). Furthermore, despite of the presence of nitro-L-arginine methyl ester (0.1 mmol/L), a nitric oxide synthase (NOS) inhibitor, TNF-alpha reversed the Iso-induced increase in I(Cl) (n=5). These results suggest that TNF-alpha rapidly antagonizes the beta-adrenergic responses of I(Cl) by reducing cAMP concentration. This anti-adrenergic action is mediated by neither the PTX-sensitive G proteins regulatory pathway nor constitutive NOS activation.

Adrenergic beta-Agonists↗

PubMed2002

Ca2+ overload evokes a transient outward current in guinea-pig ventricular myocytes.

There are 2 types of transient outward currents (Ito) in the hearts of various mammals: a 4-aminopyridine (4-AP) sensitive K+ current and a 4-AP resistant Ca2+ activated current, carried by Cl-, (referred to as I(to1) and I(to2), respectively). However, the I(to) has been considered to be absent in guinea-pig ventricular myocytes and so this study tested the hypothesis that I(to1) is generally absent in guinea-pig ventricular myocytes, but I(to2) appears under the condition of Ca2+ overload. Membrane currents were recorded by the whole-cell patch-clamp technique and Ca2+ overload was achieved by adding internal, and eliminating external, Na+ with subsequent enhancement of Ca2+ influx via the Na+-Ca2+ exchange. Under physiological conditions, I(to) could not be elicited by 300 ms-test pulse from -70 mV to 0 mV (n=32). However, under Ca2+ overload, a biphasic current resulting from the overlap of the L-type Ca2+ channel current and Ito was elicited (n=38). This I(to) was resistant to 4-AP (3 mmol/L, n=30) but sensitive to both anthrancene-9-carboxylic acid (9-AC, 3 mmol/L, n=8) and 4,4'-diisothiocyanatostilbene-2,2'-disulfonic acid (100 micromol/L, n=3). Replacing K+ with Cs+ on both sides of the membrane failed to abolish I(to) (n=38). I(to) disappeared by lowering the external Cl- (n=3). The amplitude of I(to) was dependent on that of the L-type Ca2+ channel current (n=4). Because Ca2+ release from the sarcoplasmic reticulum was prevented by caffeine (5 mmol/L), I(to) was negligible (n=6). These results suggest that I(to1) is absent, but Ca2+ overload evokes I(to2) in guinea-pig ventricular myocytes.

4-Aminopyridine↗

PubMed2002

Beneficial effect of dual-chamber pacing for a left mid-ventricular obstruction with apical aneurysm.

Sustained ventricular tachycardia (VT) developed in a 63-year-old woman. The 2-dimensional echocardiogram revealed left mid-ventricular obstructive hypertrophy and a discrete apical chamber. A continuous wave Doppler signal across the mid-ventricular narrowing exhibited early systolic ejection flow and diastolic paradoxical jet flow from the apex to the basal chamber, implying a significant systolic and diastolic intraventricular gradient with a high apical pressure. The left ventriculogram confirmed a mid-ventricular obstruction with an apical aneurysm. Invasive assessment of intraventricular pressure showed a peak-to-peak gradient greater than 100 mmHg. Treatment with antiarrhythmic agents could not prevent the VT, but dual-chamber pacing reduced the intraventricular pressure gradient and suppressed the VT completely. Continuous wave Doppler showed that the early systolic ejection flow from the apex had disappeared, that there was isovolumetric relaxation flow toward the apex and that there was attenuation of the diastolic paradoxical jet flow toward the basal chamber. Such findings by continuous wave Doppler can be useful in pacing therapy for evaluating changes in the severity of mid-ventricular obstruction.

Cardiac Pacing, Artificial↗

PubMedDate not supplied

Surgical treatment of a left ventricular neurofibroma.

Primary cardiac neurofibroma is a rare occurrence. We describe a case of left ventricular neurofibroma in a 56-year-old woman with Von Recklinghausen disease. Resection of the tumor with concomitant mitral valve replacement yielded a satisfactory clinical result, and histological examination of the resected tissue confirmed benign neurofibroma. The anatomic distribution of the vagus nerve plexus, which penetrates the epicardium and myocardium and courses over the left ventricular subendocardial surface, provides a tissue source from which this neurogenic tumor may arise.

Cardiac Surgical Procedures↗

PubMedDate not supplied

Comparison of volume study by left ventriculography and gated SPECT in endoventricular circular patchplasty.

Although quantitative gated SPECT (QGS) is widely used for left ventricular (LV) volume study, its accuracy is not established for those who have a large myocardial infarction scar or who had endoventricular circular patch plasty (EVCPP). Therefore, we compared LV volumes and LVEF calculated by QGS and those calculated by left ventriculography (LVG) before and after EVCPP. Sixteen patients (13 men and 3 women, mean age 67 +/- 9.5 years) were treated with EVCPP for postinfarction LV dyskinetic and/or akinetic scar. All patients were evaluated with both QGS and LVG before and after surgery. QGS was performed using eight frames per cardiac cycle, 1 hour after 740 MBq (99 m)Tc-tetrofosimin was administered. LVG images were acquired at a frame rate of 30 frames per second in the right anterior oblique 30-degree projection. We compared LV end-diastolic volume (LVEDV), LV end-systolic volume (LVESV), and LV ejection fraction (LVEF) between QGS and LVG. There was an excellent linear correlation between QGS and LVG in LVEDV (preoperative; r = 0.87, postoperative; r = 0.94), LVESV (preoperative; r = 0.95, postoperative; r = 0.89), and LVEF (preoperative; r = 0.73, postoperative; r = 0.81) before and after EVCPP. However, both preoperative LV volumes and postoperative LVEF calculated from QGS gave a smaller value than those calculated from LVG. Postoperative volume data by QGS was much close to LVG. The present study indicated that volume study by QGS is very useful to evaluate the LV function after EVCPP. However, we should pay attention to those facts.

Aged↗

PubMedDate not supplied

Surgical treatment of multiple coronary artery fistulas with an associated small saccular aneurysm--a case report.

Coronary angiography (CAG) of a 57-year-old woman with anterior chest discomfort revealed no stenosis of the coronary arteries but multiple coronary artery fistulas (CAFs). The sites of origin for the CAFs were the right coronary artery, left main coronary artery, left anterior descending coronary artery, and ascending aorta. The only site for drainage was the main pulmonary artery. Furthermore, a small saccular aneurysmal formation was detected. Surgical treatment was considered better than conservative treatment or coil embolization, and ligation and division of the CAFs were performed during cardiopulmonary bypass. Using a Harmonic Scalpel to expose fistulous arteries was very effective. CAG performed immediately after surgery demonstrated that all CAFs were repaired. The postoperative course was uneventful.

Aorta↗