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T Kamiya

Publications and source records attributed to T Kamiya.

At least 163 records · Page 9Linked to original sources
PubMed1995

Diagnosing infection of extracardiac conduit in children.

Between August 1985 and July 1992, at our center, 142 Japanese children had an extracardiac conduit operation to reconstruct the right ventricular outflow tract. The study group consisted of 22 of these 142 children who had a persistent fever and whose serum was positive for acute-phase reactants after the operation. We present the diagnostic findings for 10 children with infection of an extracardiac conduit that had been placed to restore the continuity of the right ventricle-pulmonary artery. They were part of the group of 22 children who were followed over the past 7 years with blood cultures, echocardiography, and 67Ga imaging. All 10 developed a persistent fever and were seropositive for acute-phase reactants. Conduit infection was diagnosed in only 2 patients by the detection of vegetation on echocardiography and was diagnosed in 9 of the 10 patients by an abnormal 67Ga uptake in the area of the artificial vessels used to reconstruct the pulmonary artery. The present study compared the use of blood cultures, echocardiography, and 67Ga imaging in diagnosing an infection of the extracardiac conduit. The sensitivity of blood cultures in diagnosing an extracardiac conduit infection was 70% (7/10), and the specificity was 92% (1/12). 67Ga imaging showed a higher sensitivity than echocardiography in diagnosing infection of an extracardiac conduit.

Acute-Phase Proteins↗
PubMed1995

A bicuspid pulmonary valve is not a contraindication for the arterial switch operation.

There are no obvious criteria concerning the optimal repair for complete transposition with bicuspid pulmonary valve if neither the organic changes in the valve nor the pressure gradient between the left ventricle and the pulmonary trunk are severe. Instead of intraatrial switching or intraventricular rerouting in such circumstances, we have proceeded to the arterial switch procedure in 6 patients with an adequate diameter of the pulmonary valve (greater than 100% of the calculated normal aortic orifice). Postoperative catheterization (at approximately 8 months after the procedures) showed no pressure gradient between the left ventricle and the neoaorta except for a finding of 34 mm Hg difference in 1 patient who had undergone simultaneous subpulmonary myotomy. Echocardiography (7 years later in the longest follow-up) has shown no more than slight regurgitation across the bicuspid neoaortic valve, with no progressive increase of blood velocity across the valve. From these results in the middle term, we conclude that the arterial switch procedure remains an option of choice for patients with initially bicuspid pulmonary valve, providing there is no severe subpulmonary stenosis.

Aorta↗
PubMed1995

Coronary arterial anatomy in double-outlet right ventricle with subpulmonary VSD.

We have examined 38 hearts with a double-outlet right ventricle with a subpulmonary ventricular septal defect. We divided the hearts into three groups according to the angle between the planes formed between the outlet septum and the remainder of the muscular ventricular septum; namely, at approximately right angles (15 hearts), parallel (11 hearts), and at an acute angle (12 hearts). The coronary arterial pattern corresponding to that seen in the normal heart was present in 11 hearts (73%) of the "right angle" group, in only one heart (8%) of the "acute angle" group, and in none of the "parallel" group. In contrast, the most common pattern in the setting of complete transposition was observed in none, 8%, and 91% of each group, respectively. Other diverse patterns were recognized in the hearts in the acute angle group, and the incidence of abnormal branching was significantly higher in this than in the other groups (p < 0.01). Knowledge of these anatomic variations in the course of the coronary arteries, some of which would cause problems at either definitive repair or reoperation, are essential for those seeking to achieve optimal surgical repair.

Coronary Vessel Anomalies↗
PubMed1995

Intrapulmonary reconstruction of pulmonary arteries using a heterologous pericardial roll.

Pulmonary artery reconstruction using a handmade heterologous pericardial roll was achieved in 5 patients with severe hypoplasia of the intrapericardial pulmonary arteries and in 9 patients with critical hilar pulmonary stenosis occurring subsequent to previous construction of a systemic-pulmonary shunt. The pericardial roll was 12 to 16 mm in diameter and was anastomosed to the pulmonary arteries through divided interlobar fissures. At the opposite end, it was fixed anteriorly to the chest wall and connected to a prosthetic tube so as to obtain a blood supply from the systemic circulation. The flow through the roll measured intraoperatively was 95 +/- 23 mL.kg-1.min-1. Postoperative catheterization showed that the mean pressure in the roll was 31 +/- 18 mm Hg. Eleven patients have subsequently undergone anatomic repair using an external conduit after 8 +/- 4 months. There were no operative deaths, but 1 patient died of esophageal bleeding after the definitive intracardiac repair. We conclude that this technique is a feasible surgical option as a part of staged operations leading to biventricular repair.

Adolescent↗
PubMed1995

Retrospective study of inhibitor formation in Japanese hemophiliacs.

We conducted a retrospective study on the rate of occurrence of inhibitor (factor VIII or factor IX antibody) formation in Japanese hemophiliacs, and examined some possible causes. The records of 51 medical institutions were analyzed. Inhibitors were found in 6.08% (101/1661) of the patients with hemophilia A and 4.17% (13/312) of those with hemophilia B. The median age for antibody formation was 11 (0.8-75.9 years old, n = 94) with hemophilia A, and 4 (1-42 years old, n = 13) with hemophilia B. Among the patients with inhibitors, 69.7% (62/89) of the hemophilia A cases and 81.8% (9/13) of the hemophilia B cases were classified as high responders (> 10 Bethesda units (BU)/ml). The median time from initial exposure to plasma factor concentrates until inhibitor formation (exposure days) was 46 days (4-162 days, n = 51) with hemophilia A and 30 days (2-151 days, n = 8) with hemophilia B. Studies on 15 families with two hemophiliacs showed a non-random distribution of antibodies. Gene analysis was performed in three patients with hemophilia A. A large gene deletion was detected in two cases and a nonsense mutation in one. Analysis of eight patients with hemophilia B revealed a large deletion in five cases and a nonsense mutation in three. The antibodies in these eight hemophiliacs whose mutation site was identified were found between the ages of one and nine. Of these, six patients were less than 4 years old. All these patients were considered high responders as they all exhibited a high inhibitor potency. Of the six hemophiliacs for whom the number of exposures could be determined, four became high responders with fewer than 10 exposures.

Adolescent↗
PubMed1995

What factors affect ventricular performance after a Fontan-type operation?

Postoperative conditions after a Fontan-type operation, particularly as they affect results in the early term, are thought to depend on factors such as the state of pulmonary circulation and ventricular function. In this study, we attempted to determine the factors that influence ventricular characteristics in the middle term after Fontan-type procedures. Catheterization was performed at a mean of 15 months after operation in 57 patients with univentricular atrioventricular connection who underwent the operation between 1.0 and 22.6 years of age. End-diastolic volume, end-systolic volume, ejection fraction, and end-diastolic pressure of the systemic ventricle were analyzed together with an estimation of the systemic flow index. These parameters were influenced significantly by the presence of atrioventricular valve insufficiency. The morphologically left ventricle showed a better ejection fraction than did the morphologically right ventricle, whereas the systemic flow index was greater in patients undergoing total cavopulmonary connection than in those receiving an atriopulmonary connection. Young age was significantly associated with a better postoperative contractility, whereas the potential for impaired ventricular compliance was suggested in several patients undergoing operation after 4 years of age. On the basis of our results, we conclude that total cavopulmonary connection performed at a young age should be the surgical procedure of choice and that atrioventricular insufficiency must be treated properly at, and even after, the initial definitive repair.

Adolescent↗
PubMed1995

Significance of dipyridamole loading in ultrafast x-ray computed tomography for detection of myocardial ischemia. A study in patients with Kawasaki disease.

BACKGROUND AND RATIONALE: To examine the significance of dipyridamole loading as a stress in ultrafast computed tomography (CT) to improve the detection of left ventricular myocardial ischemia. METHODS: Thirty-eight patients with coronary arterial involvement of Kawasaki disease and 18 control subjects received cardiac ultrafast CT with intravenous long-bolus iodinated contrast injection; dipyridamole was loaded in 40 examinations. Early (first-pass) and late (4 minutes) M/Ls (ratio of postcontrast incremental increases in the left ventricular myocardial [M] and luminal [L] CT number) were analyzed. RESULTS: Dipyridamole induced a prominent increase in early M/L of the normal myocardium in control subjects (no loading: 26.8%, dipyridamole: 39.2%; P < 0.001) with small influence on late M/Ls. In ischemic or infarcted myocardium in Kawasaki disease, dipyridamole early M/Ls (20.4%, 16.0%) and late M/Ls showed no difference from corresponding values without loading. Using early M/L with dipyridamole, sensitivity and specificity for detection of ischemic abnormalities were 89% and 100%, respectively. CONCLUSIONS: Dipyridamole-loaded first-pass contrast ultrafast CT was proven to have excellent detectability for myocardial ischemia comparable with stress thallium scintigraphy.

Adolescent↗
PubMed1995

Abnormal response to exercise, face immersion, and isoproterenol in children with the long QT syndrome.

The present study was performed to observe the change of QT interval by sympathetic stimulations in patients with the long Qt syndrome (LQTS). The study group consisted of 6 children with LQTS and 6 healthy children without QT prolongation. All LQTS patients had syncopal episodes. The QTc and delta QTc% ([QTc interval after examination-QTc interval at rest]/ QTc interval at rest x 100) by treadmill testing, face immersion, and isoproterenol were examined. One minute after peak exercise of treadmill testing, the changes in the QTc interval were not significant in either group, but delta QTc% was larger in the LQTS group than in the control group (+ 11.0 +/- 12.1% vs -2.6 +/- 3.2%; P = 0.02). The QTc interval at the shortest RR interval during face immersion was prolonged in the LQTS group (0.47 +/- 0.01 s to 0.51 +/- 0.04 s; P = 0.02), but there were no significant changes in the control group (0.40 +/- 0.03 s to 0.41 +/- 0.03 s; P = NS). delta QTc% was larger in the LQTS group than in the control group (+ 10.0 +/- 7.3% vs +1.1 +/- 5.5%; P = 0.04). In the LQTS group, the RR interval was shortened (P = 0.009) and QTc interval was prolonged (P = 0.0008) after isoproterenol infusion. These sympathetic stimulations amplified the TU abnormality in the LQTS group. By observing the TU changes caused by face immersion, we hoped to find a possible new method with which to diagnose LQTS. The combination of these examinations may be helpful in screening the borderline cases of TU abnormalities.

Adolescent↗
PubMed1995

Provocative testing and drug response in a patient with the long QT syndrome.

A girl of 14 with the long QT syndrome (LQTS) and torsades de pointes is reported. Isoprenaline or adrenaline infusions induced torsades de pointes and inversion of the TU wave. Changes in the TU wave during isoprenaline infusion were used to select effective drugs to treat this patient. A beta blocker and calcium channel blocker were selected and the patient had no episodes of syncope for two years. This electrocardiographically guided method may be useful for selecting effective drugs in patients with the LQTS.

Adolescent↗
PubMed1995

[Vasodilating effects of NY-008 in ring preparation of rat aorta].

Vasodilating effects of NY-008 were compared to those of verapamil in isolated rat aorta. NY-008 at the dose of 3 x 10(-5) M relaxed 10-70 mM potassium chloride (KCl)-induced contraction. NY-008 relaxed preparations precontracted with 60 mM KCl concentration-dependently with an IC50 of (6.17 +/- 1.75) x 10(-6) M, and those precontracted with norepinephrine (NE) (10(-6) M) concentration-dependently, maximally by 90.0 +/- 2.86%, with an IC50 of (2.06 +/- 0.38) x 10(-5) M. At 10(-8)-3 x 10(-6) M, verapamil relaxed preparations precontracted with NE (10(-6) M) concentration-dependently, maximally by 55.9 +/- 5.56%. At 3 x 10(-5) M and 10(-4) M, NY-008 relaxed (10(-6) M)-induced phasic contractions in a Ca(2+)-free 1 mM EGTA-containing buffer, by 22.4 +/- 3.69% and 35.4 +/- 5.74%, respectively. In contrast, 3 x 10(-7) M verapamil did not. NY-008 concentration-dependently decreased the maximal responses to calcium chloride (CaCl2) in 60 mM KCl-depolarized preparations, and it shifted the ED50 values of CaCl2 to the right, whereas verapamil shifted the ED50 values of CaCl2 to the right without decreasing the maximal responses to CaCl2. At 10(-5)-3 x 10(-4) M, NY-008 concentration-dependently relaxed preparations precontracted with prostaglandin F2 alpha (10(-5) M) in a Ca(2+)-free, 0.5 mM EGTA-containing buffer, whereas 10(-7)-10(-5) M verapamil did not. These results suggest that NY-008 antagonized Ca2+ and decreased the Ca(2+)-sensitivity of contractile elements or inhibited contractile proteins in rat aorta.

Animals↗
PubMed1995

Plasma brain natriuretic peptide concentrations in healthy children from birth to adolescence: marked and rapid increase after birth.

The aim of the present study is to establish the normal range and to determine the developmental changes of plasma brain natriuretic peptide (BNP) concentrations in children. We measured plasma BNP concentrations as well as atrial natriuretic peptide (ANP) concentrations in 58 healthy children from birth to adolescence and in the umbilical vein of 20 healthy neonates using highly sensitive immunoradiometric assays. The plasma BNP concentration was the highest at 0 days of age and descended through maturation to be almost constant and to be at the adult level at 3 months of age. The plasma BNP concentration at 0 days of age (56.7 +/- 49.6 fmol/ml; mean +/- SD) was 25 to 30 times higher than the adult level and 21 times higher than that in the umbilical vein (2.7 +/- 1.4 fmol/ml). The plasma ANP concentration at 0 days of age was not significantly different from that in the umbilical vein. The ratio of BNP to ANP was also the highest at 0 days of age (1.39 +/- 0.72) and decreased through maturation to be at the adult level at 3 months of age. Thus, the plasma BNP concentration in healthy subjects showed a marked, rapid and preferential increase immediately after birth, suggesting that BNP has a physiological role distinct from that of ANP in the perinatal circulatory changes from fetus to neonate.

Adolescent↗
PubMed1995

Inhibition and down-regulation of poly(ADP-ribose) polymerase results in a marked resistance of HL-60 cells to various apoptosis-inducers.

In a previous report we described that adenosine-induced apoptosis of HL-60 cells was blocked by the pretreatment of cells with a potent inhibitor (3-aminobenzamide) of poly(ADP-ribose) polymerase (PARP). The pretreatment of the cells with nicotinamide, another inhibitor of the enzyme, also suppressed most effectively the adenosine-induced apoptosis. This inhibition was reversible and observed during apoptosis mediated by other known apoptosis inducers such as actinomycin D and staurosporine (group I inducers), but nicotinamide was ineffective on the apoptosis mediated by VM 26, camptothecin and A23187 (group II inhibitors). In addition to the enzyme inhibition, a down-regulation of the enzyme level caused by the pretreatments of cells with differentiation-inducing agents, retinoic acid (RA) and dimethylsulfoxide (DMSO) also resulted in a marked resistance of the cells to the apoptosis inducers. A pretreatment of the cells for a limited time of 24 hrs. by these agents decreased the PARP level to 66-75% of the untreated cells and the cells showed a quite similar resistance to the group I apoptosis inducers like the cells treated with the enzyme inhibitors, whereas they were still sensitive to the group II inhibitors. A more prolonged treatment for 48 hrs. of the cells with RA and DMSO resulted in further down-regulation of the cellular PARP reaching respectively 50 and 43% of control cells and at this stage, the cells became resistant to all the inducers of both groups. These results suggest that the pathway, by which both groups of the inducers initiate and progress apoptosis, is not identical but include at least two different processes which are differently affected by PARP-inhibition or by different levels of cellular PARP.

Adenosine↗
PubMed1995

Regurgitation through the morphologically pulmonary valve after additional aortopulmonary anastomosis.

Although additional aortopulmonary anastomosis established by creating double outlet from the systemic ventricle and anastomosing the pulmonary trunk to the ascending aorta can undoubtedly provide an unobstructed outlet for the systemic ventricle, postoperative regurgitation of the morphologically pulmonary valve, if it occurs, may spoil the efficacy. To determine whether the pulmonary valve can be regurgitant, 11 patients undergoing this surgical option, six accompanying a Fontan-type operation and five associated with biventricular repair, were reviewed. Postoperative regurgitation was observed echocardiographically in five patients. One patient with severe pathologic changes of the valve showed progressive regurgitation, necessitating valve replacement two months after the aortopulmonary anastomosis. The other four patients, including one with slight thickening of the pulmonary leaflets, had previously undergone banding of the pulmonary trunk. Slight regurgitation in these cases appeared between one month and two years after the procedure, but then neither progressed nor regressed. Pathologic changes of the pulmonary valve, and previous banding, therefore, can be recognized as risk factors for postoperative regurgitation. The morphologically pulmonary valve, nonetheless, proved to be feasible for this surgical option unless it possessed severe organic changes.

Anastomosis, Surgical↗