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Biomedical subjects

M Fukazawa

Publications and source records attributed to M Fukazawa.

At least 37 records · Page 2Linked to original sources

Bilateral congenital cholesteatoma.

We report a case of bilateral congenital cholesteatoma in a 6-year-old boy. Cholesteatoma was present in both ears around the tympanic isthmus (the only open passage from the tympanic cavity to the attic), extending to behind the horizontal portion of the facial nerve. This patient underwent a total of three canal wall up operations on each side to remove the cholesteatoma completely and improve hearing. This case fulfills the criteria proposed by Derlacki and Clemis in 1965. Bilateral congenital cholesteatoma is a rare condition, but the incidence of congenital cholesteatoma in children has increased recently for the following reasons: Reassessment of the criteria, the introduction of computed tomography, and increased awareness of congenital cholesteatoma. When operating on patients with bilateral cholesteatoma, the best method for preservation of hearing should be chosen. We discuss these problems in the present report.

Cartilage↗

Effect of endothelin on angiotensin converting enzyme activity in cultured vascular smooth muscle cells.

We evaluated the effect of endothelin-1 (ET) on the angiotensin converting enzyme (ACE) activity in rat aortic smooth muscle cells (VSMCs). ACE activity was determined by radioimmunoassay of the amount of angiotensin II generated after the addition of angiotensin I (500 pg/ml) to cultured VSMCs. The antibody used had less than 0.1% cross-reactivity with angiotensin I. ACE activity increased 1.9-fold 5 hr after the addition of 10(-6) M ET under serum-free conditions. This stimulatory effect of ET on ACE activity in VSMCs was completely inhibited by 10(-7) M captopril. Results suggested that the ACE present in SMCs is stimulated by ET.

Angiotensin II↗

Vascular smooth muscle relaxation by alpha-adrenoceptor blocking action of dobutamine in isolated rabbit aorta.

We investigated the mechanism of vascular relaxation produced by dobutamine, a positive inotropic agent with beta 1-adrenergic action. Dobutamine concentration-dependently (10 nM-10 microM) relaxed ring segments of rabbit aorta partially precontracted with 1 microM phenylephrine (PE) but did not relax those precontracted with 40 mM K+ or 5 microM prostaglandin F2 alpha (PGF2 alpha). The relaxation was not completely inhibited by pretreatment with 10 microM propranolol. Dobutamine did not significantly increase tissue cyclic AMP levels concomitantly with relaxation as does isoproterenol (ISO) in rabbit aorta. Dobutamine produced a parallel rightward shift in concentration-response curves to PE. The Schild plot analysis resulted in a linear regression of a slope of 1.077 +/- 0.077, which was not significantly different from unity. The pA2 value of dobutamine as compared with PE in rabbit aorta was 6.81 +/- 0.03. Dobutamine causes arterial dilatation mediated not only through a beta-adrenergic action but also through an alpha-adrenergic blocking action in rabbit aorta.

Abortifacient Agents↗

[Prostaglandin E1 bladder instillations for late-onset hemorrhagic cystitis following allogeneic bone marrow transplantation].

Between July, 1990 and March, 1994, 31 patients with hematological malignancies or severe aplastic anemia underwent allogeneic bone marrow transplantation (BMT) at the Second Department of Internal medicine, Chiba University Hospital. Among the 29 evaluable patients who survived over 100 days after transplant, 11 patients (37.9%) developed late-onset hemorrhagic cystitis with a median time of onset of 57 days (range 11-205) from BMT. Adenovirus type 11 was isolated from the urine of 4 patients. Five patients recovered with fluid hydration and forced diuresis, while 6 patients had persistent gross hematuria with clot formation, 5 of whom also developed hydronephrosis. Seven-day courses of 500 micrograms prostaglandin E1 (PGE1) bladder instillations was initiated to control hematuria in these 6 patients. Complete resolution of gross hematuria was achieved in 4, and partial response with decreased clot formation and partial clearing of the urine was observed after 4 of 9 courses of the treatment. Although all patients experienced bladder spasm or lower abdominal pain during the PGE1 instillations, these symptoms were manageable with sedative drugs and morphine. No systemic side effect was apparent. PGE1 bladder instillations is a safe and useful treatment for severe, life-threatening late-onset hemorrhagic cystitis after allogeneic BMT.

Administration, Intravesical↗

[A case of pentalogy of Cantrell with tetralogy of Fallot and left ventricular diverticulum].

We report a successful repair of tetralogy of Fallot and left ventricular diverticulum associated with pentaology of Cantrell. The repair consisted of partial infundibular septectomy, closure of ventricular septum, reconstruction of right ventricular outlet using monocuspid transjunctional patch, and resection of left ventricular diverticulum. The infundibulum was extremely elongated, caused by ventricular dextroversion, and the hypoplasia of pulmonary trunk was absent. Therefore, transjunctional patch was longer, even after infundibular septectomy. This report discuss the pathogenesis of these cardiac anomalies and surgical imlication.

Abnormalities, Multiple↗

Reduced endothelium-dependent vasodilation by acetylcholine and bradykinin in isolated nitroglycerin-tolerant blood vessels.

1. Rings of porcine pulmonary arteries were mounted in tissue organ baths and incubated in physiological solution. The rings were allowed to equilibrate for > 1 hr under a resting tension of 1.0 g. The presence of endothelium was confirmed by 10(-6) M acetylcholine (ACh)-induced relaxation (60-80%) of 10(-6) M norepinephrine (NE) contraction. 2. Relaxation response generated by nitroglycerin (NTG) (10(-9) - 10(-5) M), ACh (10(-9) - 10(-5) M), bradykinin (BK) (10(-13) - 10(-6) M) and nitric oxide (NO) after NE (10(-6) M) contraction was compared before and after 1 hr treatment of NTG (5 x 10(-4) M). Then tissues were pretreated with NG-monomethyl-L-arginine (LNMMA) (10(-4) M) each before and after NTG treatment respectively, and ACh-induced relaxation was compared. 3. After 1 hr treatment with 5 x 10(-4) M NTG, the relaxation response of NTG at concentrations > 10(-7) M was attenuated significantly. This indicates that 1 hr treatment with 5 x 10(-4) M NTG induces NTG tolerance in isolated porcine pulmonary arterial rings. 4. The relaxation response of ACh at concentrations > 10(-7) M was attenuated significantly after NTG tolerance induction. 5. Relaxation response of BK at concentrations > 10(-10) M was attenuated significantly after NTG tolerance induction. 6. NTG tolerance had no effect on NO-induced vascular smooth muscle relaxation. 7. The relaxation response of ACh pretreated with LNMMA at concentrations higher than 10(-7) M was attenuated after NTG tolerance.(ABSTRACT TRUNCATED AT 250 WORDS)

Acetylcholine↗

Endothelium-dependent relaxation by angiotensin-converting enzyme inhibitors in canine femoral arteries.

The effects of angiotensin-converting enzyme (ACE) inhibitors on vascular reactivity were investigated using isolated canine femoral arteries with and without endothelium. N-N-(S)-1-carboxy-3-phenylpropyl-L-alanyl-N-(indan-2-yl)glycine (M-1; an active metabolite of delapril, a nonsulfhydryl ACE inhibitor) and captopril (a sulfhydryl ACE inhibitor, 10(-8) to 10(-5) M) relaxed in a dose-dependent manner canine femoral arterial rings precontracted with prostaglandin F2 alpha in the presence of endothelium only. The endothelium-dependent relaxations by M-1 and captopril were completely blocked by methylene blue, an inhibitor of soluble guanylate cyclase; NG-monomethyl-L-arginine (L-NMMA), an inhibitor of nitric oxide synthesis; and oxyhemoglobin, an inactivator of nitric oxide; they were partially blocked by aspirin, an inhibitor of cyclooxygenase and were enhanced by superoxide dismutase, a radical scavenger. The inhibitory effect of L-NMMA on the relaxations by M-1 and captopril were reversed by a high dose of L-arginine. Moreover, a bradykinin antagonist partially inhibited these relaxations. These results suggest that endothelium-dependent relaxations by M-1 and captopril in canine femoral arteries are mediated through the release of both prostanoids and endothelium-derived nitric oxide via endogenous bradykinin.

Angiotensin-Converting Enzyme Inhibitors↗

[Cytoprotective effects of nicorandil on immature myocytes under hypothermic conditions].

We evaluated the functional and biochemical effects of nicorandil on cardiac myocytes incubated under hypothermic conditions. Cardiac myocytes were isolated from neonatal rat ventricles and cultured for 4 days. Myocytes (12.5 x 10(5) myocytes/flask) were then incubated at 4 degrees C for 24 hrs in media with nicorandil as follows: O M nicorandil (group C: control), 10(-5)M (group N 1), 5 x 10(-5)M (group N 2), 10(-4)M (group N 3). After hypothermic incubation, CPK and LDH were measured. The myocytes were then cultured for 24 hrs at 37 degrees C to evaluate the recovery of myocyte beating rate. For the beating rate, group N 3 showed a significantly increased recovery compared to the control (N 3: 44.2, p < 0.02, C: 24.6 percent of control; ie, beating rate prior to hypothermic incubation). The release of CPK and LDH was significantly suppressed in group N 3 compared to the control (N 3: 24.1, p < 0.005, 247.2, p < 0.01; C: 125.4 mIU/flask, 459.5 mIU/flask, respectively). Thus, nicorandil has cytoprotective effects on immature myocytes under hypothermic conditions.

Animals↗

[A rare case of total anomalous pulmonary venous connection to the right atrium confounding with cor triatrium].

Three-days-old newborn baby underwent ligation of the ductus arteriosus under the diagnosis of TAPVC and PDA with high flow heart failure. Her UCG showed the direct connection of common pulmonary venous chamber (CPVC) to the upper and medial portion of right atrium. CPVC positioned just above the left atrium but does not communicated with the left atrium. These findings characterized this anomaly as II A cor triatriatum classified by Lucus-Schumidt. At 5-month-old, corrective operation was performed. Both right and left venous chambers joined just before the connection to right atrium and drained to right atrium at the upper portion of atrial septum. CPVC and left atrium had independent wall. Accordingly, operative diagnosis was made as TAPVC (IIb). Intraatrial routing was performed using porcine pericardial patch. At 6 months after operation, patient is doing well without the sign of venous obstruction. This type of TAPVC is rare and may confound with cor triatriatum. Our case may suggest the pathological mechanism of cor triatriatum and that at least some of cor triatriatum may be identical with TAPVC.

Cardiac Surgical Procedures↗

[A combination chemotherapy of mitoxantrone, etoposide, carboplatin, and prednisolone (MECP) in recurrent or refractory non-Hodgkin's lymphomas].

Twenty-two patients with recurrent or refractory non-Hodgkin's lymphoma were treated with a combination chemotherapy of mitoxantrone, etoposide, carboplatin, and prednisolone (MECP). Of 22 evaluable patients, 11 (50%) responded to MECP and 7 (32%) achieved complete remission. Particularly in relapsed cases, 9 (75%) responded and 6 (50%) achieved complete remission. Myelosuppression was the major toxicity. Thirteen patients (59%) experienced WBC counts under 1,000/microliters, and thrombocytopenia under 50,000/microliters was seen in 12 patients (55%). During myelosuppression, 2 patients developed sepsis and 1 showed intestinal bleeding. Other gastrointestinal toxicities were well tolerated. There was no death due to chemotherapy. These results show that MECP is a well-tolerated treatment regimen, and effective for recurrent or refractory non-Hodgkin's lymphomas.

Administration, Oral↗

Discordance between thallium-201 scintigraphy and coronary angiography in patients with Kawasaki disease: myocardial ischemia with normal coronary angiogram.

To assess the usefulness of radionuclide tests in detecting coronary occlusive lesions in children with Kawasaki disease, we compared the results of stress thallium-201 myocardial single photon emission computed tomography with dipyridamole infusion and coronary angiography in 34 patients (19 males and 15 females). Perfusion defects on the stress image only were categorized as transient and were attributed to coronary vascular disease in the presence of redistribution on the delayed image. Others were classified as persistent, due to myocardial damage. Five of the seven children (71%) with severe stenosis on coronary angiography showed persistent and/or transient perfusion defects. However, six of the 11 children (55%) with aneurysms but no obvious stenosis, and four of the 16 children (25%) with normal angiography, showed persistent and/or transient defects. After analyzing 20 individual segments of perfusion defects in the 15 children, six segments (30%) were attributed to the stenosis of supplying coronary arteries, six segments (30%) were related to the coronary aneurysms, and eight segments (40%) were unrelated to any abnormalities on angiography. Thus, significant discordance between the radionuclide and angiographic studies was demonstrated. These results suggest that coronary lesions, as conventionally defined by angiography and supplemented by echocardiography, may not completely identify all Kawasaki patients who may develop myocardial ischemia in the future or who had ischemia in the past.

Adolescent↗

[In vitro evaluation of prostaglandin I2 analogue on hypothermic injury to immature myocytes].

We evaluated the functional and biochemical effects of prostaglandin I2 analogue (PGI-A) on cardiac myocytes incubated under hypothermic conditions. Myocytes were isolated from neonatal rat ventricles and cultured for 4 days. Then, myocytes (12.5 x 10(5) myocytes/flask) were incubated at 4 degrees C for 24 hrs in media with PGI-A as follows; O M PGI-A (group C: control), 10(-9) M (group P1), 10(-8) M (group P2), 10(-7) M (group P3), 10(-6) M (group P4). After hypothermic incubation, CPK and LDH were measured. The myocytes were then cultured for 24 hrs at 37 degrees C to evaluate the recovery of myocyte beating rate. For the beating rate, group P2 showed significantly increased recovery compared to the control (P2: 47.9, p < 0.025, C:18.1 percent of control; ie, beating rate prior to hypothermic incubation). The release of CPK and LDH was significantly suppressed in group P2 compared to the control (P2:57.7, p < 0.05, 275.1, p < 0.025; C:96.8 mIU/flask, 439.6 mIU/flask, respectively). In conclusion, prostaglandin I2 has direct cytoprotective characteristics for immature myocytes that may be suitable for cardiac preservation.

Animals↗

Anomalous origin of the left coronary artery from the right pulmonary artery: report of a case.

A 1-year-old boy was referred to our hospital for further investigation of mitral regurgitation. Color-Doppler echocardiography revealed the site of the anomalous origin of the left coronary artery which was confirmed by a cineangiographic study. This case is interesting for several reasons: the first is that the anomalous left coronary artery originated from the right pulmonary artery; the second is that two-dimensional echocardiographic findings can be misleading, i.e., a vessel-like structure which seemed to be the left coronary artery arising normally from the aorta was visualized; and the last is that a two-dimensional color-Doppler echocardiogram was useful in the diagnosis of the anomalous origin of the left coronary artery. The patient underwent implantation of the anomalous left coronary artery as well as Kay's plasty of the mitral valve, and has been doing well since then.

Coronary Vessel Anomalies↗

Granulocyte-colony stimulating factor stimulates immunoreactive endothelin-1 release from cultured bovine endothelial cells.

We examined the effect of human recombinant granulocyte-colony stimulating factor (G-CSF) on the release of immunoreactive endothelin-1 (ET-1) from cultured bovine vascular endothelial cells. G-CSF dose dependently (10(-8)-10(-6) M) increased the release of immunoreactive ET-1 as a function of time under a serum-free condition. Coaddition of G-CSF and thrombin induced an additive effect on immunoreactive ET-1 release. Neither Ca2+ channel antagonist nor cyclooxygenase inhibitor affected immunoreactive ET-1 release stimulated by G-CSF. These results suggest that G-CSF, in addition to its effect on granulocyte progenitors, has a direct effect on vascular endothelium to induce the release of immunoreactive ET-1.

Animals↗

Effect of increase in heart rate on interatrial shunt in atrial septal defect.

The effect of increases in heart rate by atrial pacing was investigated in 20 children [mean 9 +/- 4 (SD) years] with atrial septal defect. Systemic blood flow increased by 13 +/- 10 and 27 +/- 22% with a 25 and 50% increase in heart rate, respectively. Pulmonary blood flow, however, remained unaltered. Thus, rapid pacing decreased the pulmonary to systemic blood flow ratio significantly (-15 +/- 10 and -22 +/- 13%, respectively). This hemodynamic alteration was attributed to the difference in diastolic distensibility (compliance) between the left and right ventricles, and the ratio of right ventricular to left ventricular compliance (defined by dV/dP) near the end-diastolic pressure was estimated to be 6.5 +/- 4.2. It is suspected that the increase in heart rate may contribute to the lowering of pulmonary to systemic flow ratio during exercise in children with atrial septal defect.

Adolescent↗

Cardiac beriberi (shoshin beriberi) caused by excessive intake of isotonic drink.

A 21 month old female had voluntarily ingested 0.5-1.51 of isotonic sports drink daily from 10 months of age. She developed hyponatremia and beriberi heart disease, which resulted in metabolic acidosis and cardiogenic shock (shoshin beriberi). Mechanical ventilation was applied for pulmonary edema. Right heart failure was improved after administering vitamin B1. However, 5 days after the shock, hypoxemia and diffuse radiographic infiltrates progressed, and a diagnosis of adult respiratory distress syndrome (ARDS) was made. After the occurrence of an air leak, the patient died of respiratory failure. The cardiogenic shock and pulmonary edema due to cardiac beriberi may have triggered the ARDS.

Beriberi↗