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Biomedical subjects

T Kamiya

Publications and source records attributed to T Kamiya.

At least 127 records · Page 7Linked to original sources
PubMed1997

Effects of inhaled nitric oxide on postoperative pulmonary circulation in patients with congenital heart disease.

We studied 22 patients with residual pulmonary hypertension or symptoms of postoperative pulmonary hypertensive crisis. They received low-dose inhalation (10 ppm) of nitric oxide (NO), a selective pulmonary vasodilator, after total correction for congenital heart anomalies. Fifteen minutes of NO inhalation improved the pulmonary circulation and lessened the imbalance in the ventilation-perfusion ratio in both groups. Thus, NO inhalation is effective in the treatment of pulmonary hypertension and in the prevention of pulmonary hypertensive crises after total correction for congenital heart anomalies. All patients continued to receive NO therapeutically. The duration of such therapeutic NO inhalation was well correlated with postoperative Qp/Qs (p = 0.014) and Rp/Rs (p = 0.029).

Administration, Inhalation↗
PubMed1997

Cytomegalovirus glycoprotein B sequence variation among Japanese bone marrow transplant recipients.

Glycoprotein B (gB) of human cytomegalovirus (CMV) is the major target protein of neutralizing antibodies, and four variant types are known. A previously reported polymerase chain reaction (PCR)-restriction fragment length polymorphism (RFLP) method was modified by eliminating the cell culture step and amplifying a CMV fragment (corresponding to a.a. 441-450 of gB) by nested PCR. DNA was extracted from the sera of 27 pediatric bone marrow transplant recipients and subjected to nested PCR. Of the samples, 20 yielded PCR products, and the gB type was determined by RFLP. Of the 20 patients, 4 (20%) had gB type 1 (Towne type), 15 patients (75%) had gB type 2 (AD 169 type), and 1 patient (5%) had gB type 3. Previous studies showed that gB type was most common among Caucasians [Chou and Dennison: J Infect Dis 1991;163:1229-1234; Fries et al: J Infect Dis 1994;169:769-774]. Thus, gB genotypes seem to be distributed differently in Caucasians and Japanese. Further, nucleotide sequence analysis of the amplified region revealed that all the type 2 viruses had the same amino acid sequences. The type 3 sample had a novel amino acid substitution at position 498. Of the type 1 samples, 3 had amino acid substitutions in various positions: 1 sample at position 493, 1 sample at position 447 and 1 sample at position 452, 493 and 498.

Bone Marrow Transplantation↗
PubMed1997

Balloon angioplasty for aortic coarctation--report of a questionnaire survey by the Japanese Pediatric Interventional Cardiology Committee.

The aim of this study was to analyze the results of a questionnaire survey regarding acute and late effects of balloon angioplasty for aortic coarctation in Japan. Considerable controversy still exists regarding the effectiveness and safety of balloon angioplasty in native coarctation. Moreover, little information about this mode of treatment is available from Japan. A questionnaire was sent to 55 Japanese institutions with pediatric cardiology units. A total of 208 patients from 35 institutions were reported and analyzed for indications for balloon angioplasty, acute and late results, and complications. Balloon angioplasty was performed in 56 patients with native coarctation (group I) and in 152 patients with postoperative recoarctation (group II). In group I, the pressure gradient across the coarcted site decreased significantly from 34 +/- 19 to 16 +/- 21 mmHg (p < 0.001), and the diameter of the coarcted site increased significantly from 3.7 +/- 1.7 to 6.0 +/- 2.5 mm (p < 0.001). In group II the pressure gradient significantly decreased from 41 +/- 20 to 15 +/- 15 mmHg (p < 0.001) and the diameter of the coarcted site significantly increased from 4.2 +/- 2.2 to 6.8 +/- 3.1 mm (p < 0.001). The restenosis rate was significantly higher in group I (19/41, 46%) than in group II (25/139, 18%) (p = 0.0006). Redilation was successfully performed in 27 of 29 of the patients with restenosis. Major complications included femoral pulse loss, transient bradycardia, and arrhythmia. No patient died of a cardiac event related to the procedure. The significant risk factors for late restenosis included type of coarctation, age under 4 months, balloon size used, pressure gradient and coarctation diameter before the procedure. Balloon angioplasty is a suitable treatment for aortic coarctation in both native coarctation and postoperative recoarctation. Restenosis was significant after initial balloon angioplasty in native coarctation but redilation was effective in most cases. The most significant risk group for restenosis is young children with native coarctation.

Adolescent↗
PubMed1997

Alveolar-arterial gas tension differences during progressive exercise in patients after the Fontan operation.

We investigated alveolar-arterial gas tension differences as a measurement of ventilatory impairment during exercise in patients who had undergone the Fontan operation. The ventilatory response to exercise in 13 operated patients was compared with that of 11 control subjects. The difference between end-tidal and arterial oxygen tension (P(ET-a)DO2) and between arterial and end-tidal carbon dioxide tension (P(a-ET)DCO2) as well as the physiologic dead space-tidal volume ratio were calculated during progressive treadmill exercise testing. In the Fontan group, P(ET-a)DO2 and P(a-ET)DCO2 were significantly higher than in control subjects and increased in parallel during the study period. The physiologic dead space-tidal volume ratio was higher in the Fontan group than in the control group, and the difference in these ratios between the values obtained using end-tidal carbon dioxide tension and those using arterial carbon dioxide tension correlated well with P(a-ET)DCO2 (r = -0.79 to -0.98, p < 0.001). The physiologic dead space-tidal volume ratio during exercise was significantly higher in patients with low exercise capacities than in those with high exercise capacities (p < 0.05). The alveolar-arterial gas tension differences during exercise were greater in Fontan patients than in control subjects. We conclude that the size of the physiologic dead space can be evaluated from measurements of arterial carbon dioxide tension and is correlated with impaired exercise capacity after the Fontan operation.

Adolescent↗
PubMed1997

Coil occlusion for patent ductus arteriosus in Japan.

We surveyed Japanese experience of coil occlusion of patent ductus arteriosus up to 30 September 1996 by sending questionnaires to 175 hospitals. Thirty-four hospitals reported outcome data for 231 procedures in 218 patients. Successful implantation was achieved in 94% and acute complete closure of the ductus occurred in 71% of those in whom implantation of the coil was successful. Of the latter, 83% reported late complete closure. When those patients who underwent reocclusion for residual shunt are included, 89% attained complete closure. No life-threatening complications have occurred so far. Late reopening was reported in 3 cases. Although the angiographic type of ductus was significantly related to successful implantation (p < 0.01), there was no significant correlation with complete occlusion. Ductuses with a minimum diameter greater than 3 mm had a decreased chance of successful implantation, whereas those less than 2 mm had a greater incidence of complete closure.

Child↗
PubMed1997

Intraatrial rerouting in left isomerism and late complications.

We performed a total repair for a 1-year-old boy with left isomerism, a common atrium, incomplete atrioventricular septal defect and hemiazygos continuation. The operation performed was intraatrial rerouting with a baffle and mitral repair. The postoperative course was uneventful. However, two and a half years after the total repair, the patient revealed obstruction of the systemic atrium constructed by the baffle and the left ventricular outflow tract. Reoperation to relieve these obstructions was successful.

Cardiac Surgical Procedures↗
PubMed1997

[Abnormally distributed regional cerebral blood flow in brain malformations detected by single photon emission computed tomography].

Brain malformations are rare congenital anomalies caused by neuronal migration disorders or cerebral tissue destruction during gestation. And epileptic disorders and psychomotor retardation are sometimes induced by them. Previous understanding of these anomalies was derived from pathologic studies after autopsy. The recent advancement of neuroimaging techniques, such as magnetic resonance imaging (MRI), has allowed us to achieve a high diagnostic capability of these malformations. These abnormalities have been more widely recognized morphologically. However, cerebral function in these cases has been rarely described. To evaluate the cerebral functional state in these anomalies, 123I-N-isopropyl-p-iodoamphetamine (123I-IMP) single photon emission computed tomography (SPECT) was performed in 3 cases with brain malformations and 22 normal controls. Several regions of interest (ROI) in the cortex were determined, and the radioactivity at each ROI was counted. The regional cerebral blood flow (rCBF) distribution was evaluated semiquantitatively by calculating the cortico-cerebellar ratios at each ROI. A 23-year-old female with schizencephaly (Case-1) and a 21-year-old male (Case-2) with polymicrogyria showed increased rCBF in their abnormal cortices. And a 39-year-old male with porencephaly (Case-3) demonstrated severely decreased rCBF in his abnormal cortex with gliosis which was considered to be a result from a secondarily disturbed neuronal migration after tissue destruction during gestation. Furthermore, abnormal rCBF distribution was observed in their morphologically normal cortices in addition to their abnormal cortices compared to normal controls. Case-2 showed decreased cerebral perfusion in the morphologically normal cortex around his abnormal cortex with increased rCBF, suggesting surrounding suppression associated with epileptic foci. In contrast, the lesions with decreased rCBF in Case-1 were not around the abnormal cortices. In the cortices with decreased rCBF, despite morphologically normal imaging, of Case-3, the decrement was considered to be diaschisis, since these lesions were located in the ipsilateral hemisphere of the tissue defect. We concluded that brain malformations show various rCBF abnormalities, and these are spread over a larger area than detected by MRI. Therefore, SPECT is a valuable examination method for the determination of abnormal areas and the assessment of pathologic functional state in patients with brain malformations.

Adolescent↗
PubMed1997

[Perioperative risk factors and anesthetic management of patients for carotid endarterectomy].

Data from the records of 142 patients for carotid endarterectomy at Chugoku Rosai General Hospital between 1983 and 1995, were evaluated concerning perioperative risk factors and anesthetic management. As a preoperative anesthetic risk, the incidence of hypertension was the commonest (76%), and there was a significant incidence of ischemic heart disease (18%). Fentanyl and isoflurane have been used for anesthesia recently and the patients were closely observed and cared in the intensive care unit postoperatively. In order to prevent cerebral ischemia during the occlusion of the internal carotid artery, we measured somatosensory evoked potential as well as jugular venous oxygen saturation, and used near infrared spectophotometry. As a result, postoperative mortality and morbidity were 0% and 2%, respectively. The candidates for CEA have potentially high perioperative risks, and it is important to evaluate the coexisting diseases and to select proper anesthetic technic and monitors.

Adult↗
PubMed1997

[Anesthetic management of a child with Hunter syndrome associated with sleep apnea].

A 2-year-old boy with Hunter syndrome was scheduled for adenotomy under general anesthesia. Preoperative examinations of this patient revealed that he had stridor, sleep apnea, short neck, and a hypertrophic pharyngeal structure as revealed by fiberoptic pharyngoscopy, from which we expected to encounter difficulty in mask ventilation and tracheal intubation. On standby with settings for an emergency fiberoptic laryngoscopy and an emergency tracheotomy, we first attempted slow induction technique preserving spontaneous breathing. Thereafter mask ventilation was possible and a muscle relaxant was administered. On the second trial, almost blind orotratcheal intubation was successful. Postoperatively, mechanical ventilation was performed for 12 hours, in consideration of the airway obstruction due to pharyngeal bleeding and edema. The most severe anesthetic complication in the case of Hunter syndrome is the difficulty of intubation and respiratory disorder. Preoperative evaluation of the upper airway and careful perioperative monitoring and observation of respiration are of the greatest importance.

Adenoidectomy↗
PubMed1996

Cysteine protease activated by expression of HIV-1 protease in transgenic mice. MIP26 (aquaporin-0) cleavage and cataract formation in vivo and ex vivo.

Transgenic mice, homozygous for HIV-1 protease expression in the eye lens, display degradation of some lens crystallins and cytoskeletal proteins prior to cataract formation on postnatal days 23-25. Alterations to the internal lens hydration state also occur; therefore, the status of the aquaporin protein MIP26 was examined over postnatal days 16-25 to determine if it was altered during cataractogenesis. The MIP was identical in transgenic and control lenses until day 21. By postnatal day 25 (frank cataract), in the lenses obtained from transgenic animals, the 26-kDa band was absent and there was a concurrent increase in the proportion of MIP23. Immunoblotting demonstrated cleavage at the C terminus. Lenses were also maintained in an organ culture system to demonstrate that the cataractogenic process is inherent to the isolated lens and to determine the contribution of cysteine protease action. Organ culture experiments revealed a similar progression to nuclear cataract formation as seen in vivo. Two-dimensional gel analysis of the soluble lens crystallin fraction of organ cultured lenses revealed the same cleavage pattern as occurs in vivo. Organ culture of transgenic lenses with E64, a cysteine protease inhibitor, dramatically delayed cataractogenesis and prevented proteolytic cleavage of both MIP26 and crystallins. HIV-1 protease, while the trigger of cataract formation, does not appear to be the protease responsible for cleavage of MIP or lens crystallins. These results suggest that activation of endogenous cysteine protease activity is involved in the cleavage of these proteins and occurs downstream of HIV-1 protease action.

Animals↗
PubMed1996

Regulation of energy metabolism by interleukin-1beta, but not by interleukin-6, is mediated by nitric oxide in primary cultured rat hepatocytes.

The effects of inflammatory cytokines (interleukin-1beta, interleukin-6, and tumor necrosis factor-alpha) on energy metabolism were studied in primary cultured rat hepatocytes. Adenine nucleotide (ATP, ADP, and AMP) content, lactate production, the ketone body ratio (acetoacetate/beta-hydroxybutyrate) reflecting the liver mitochondrial redox state (NAD+/NADH), and nitric oxide formation were measured. Insulin increased ATP content in hepatocytes and had a maximal effect after 8-12 h of culture. Both interleukin-1beta and interleukin-6, but not tumor necrosis factor-alpha, significantly inhibited the ATP increase time- and dose-dependently. Interleukin-1beta and interleukin-6 also stimulated lactate production. During the same period, interleukin-1beta but not interleukin-6 decreased the ketone body ratio. Furthermore, interleukin-1beta markedly stimulated nitric oxide formation in hepatocytes, and this increase was blocked by NG-monomethyl-L-arginine (a nitric oxide synthase inhibitor) and by interleukin-1 receptor antagonist. NG-monomethyl-L-arginine reversed inhibition of the ATP increase, decrease in the ketone body ratio, and increase in lactate production, which were induced by interleukin-1beta. Interleukin-1 receptor antagonist completely abolished all of the effects induced by interleukin-1beta. These results demonstrated that interleukin-1beta and interleukin-6 affect the insulin-induced energy metabolism in rat hepatocytes by different mechanisms. Specifically, interleukin-1beta inhibits ATP synthesis by causing the mitochondrial dysfunction, a process which may be mediated by nitric oxide.

Adenine Nucleotides↗
PubMed1996

Lymphoblastic transformation of chronic myelomonocytic leukemia in an infant.

A 10-month-old infant with chronic myelomonocytic leukemia (CMML) of 5 months' duration, who had been treated only with transfusion, displayed leukemic transformation characterized by lymphoid morphology, PAS positivity, and myeloperoxidase negativity. Surface marker analysis of blast cells revealed expression of lymphoid-associated antigens (CD10 and CD19) but not myeloid-associated antigens (CD13, CD14, and CD33). These findings suggest that some cases of infantile CMML are clonal disorders arising in a pluripotent stem cell that can also differentiate along the lymphoid cell lineage.

Antigens, CD↗
PubMed1996

Long-term maintenance of monkey lenses in organ culture: a potential model system for the study of human cataractogenesis.

Lenses from Rhesus monkeys were maintained in protein-free medium and both their biochemical and histological changes were examined. Lenses were dissected under a dissecting microscope to ensure minimal contamination by other ocular tissue, which allowed successful observation of whole lens morphology during culture. Lenses in culture showed no acute leakage of protein into medium, indicating that they had not been physically damaged during dissection. Cultured lenses remained transparent for 21 days without any noticeable histological changes. Even at 21 days of culture, 35S-methionine incorporation into lens protein was approximately 60% of the level observed in fresh lenses. The amounts of most protein species were rather constant in the lens capsule/epithelium throughout culture, but the amount of crystallins gradually decreased during the first 14 days, of culture due to selective decrease in crystallin synthesis. After day 14, both the amount of crystallins and their synthesis became stable. When 30 mM fructose, present in the control medium, was replaced with 30 mM xylose, lens opacification with some histological abnormalities such as vacuole formation was observed. In the xylose-induced cataract, the protein synthetic activity decreased dramatically. This system would be a valuable tool in investigating the mechanisms of lens homeostasis as well as mechanisms of cataractogenesis in primate lens.

Animals↗
PubMed1996

Collateral vessels assessed by myocardial contrast echocardiography in patients with coronary artery lesions after Kawasaki disease.

Using myocardial contrast echocardiography (MCE), coronary arteriography, and thallium-201 myocardial imaging (TMI), we examined the characteristics and the role of collateral vessels in 35 patients with coronary artery lesions after Kawasaki disease. The male/female ratio was 25:10. The patients' ages are examination ranged from 1.0 to 20.3 years (mean, 10.8 years). The age at onset of Kawasaki disease ranged from 0.3 to 11.6 years (mean, 2.6 years). The coronary artery lesions were: dilated lesions without coexistent stenotic lesions in 5 patients (14%), localized stenosis with less than 50% narrowing in 5 patients (14%), localized stenosis with 50% or more narrowing in 4 patients (11%), and obstructive lesions, such as occlusion and/or segmental stenosis, in 21 patients (60%). In the group with no stenotic lesions and the group with less than 50% localized stenosis, the perfusion area of the right coronary artery was 32.6 +/- 8.4% and that of the left coronary artery was 76.3 +/- 7.9%. The total perfusion area of the right and the left coronary arteries was 108.9 +/- 2.6%, which value was inversely correlated with age at examination (r = 0.716, P = 0.020). In the group more than 50% localized stenosis, an increase in overlap areas detected by MCE, where a perfusion defect was seen on TMI, was not found, except in 1 patient with 99% stenosis. In the patients with obstructive lesions development of collateral channels was better in the perfusion area of the occluded right coronary artery than in that of the occluded left coronary artery, and well developed collateral channels were significantly correlated with good wall motion. We conclude that overlapping perfusion occurs in younger rather than in older children without stenotic coronary systems, and this may contribute to the food development of collateral circulation in infants and young children with coronary artery lesions after Kawasaki disease.

Adolescent↗
PubMed1996

Endoscopic treatment of a choledochocele in a 2-year-old child.

Choledochocele is an extremely rare congenital lesion of the biliary tree causing abdominal pain, pancreatitis, and obstructive cholestasis. Traditionally the therapy for this malformation has been surgery. Recently endoscopic therapy has been utilized alternatively for the treatment of choledochocele in adults. We report the case of a 2-year-old girl with a choledochocele who was treated by endoscopic sphincterotomy and placement of a biliary stent. The prosthesis was removed after 4 months. After a follow-up of 20 months the patient remains free of symptoms. Our experience suggests that endoscopic treatment of congenital biliary disease can be performed accurately. Further studies will be necessary to confirm the value of stent implantation in congenital bile duct stenosis.

Child, Preschool↗
PubMed1996

Functional behavior and morphology of the coronary artery wall in patients with Kawasaki disease assessed by intravascular ultrasound.

OBJECTIVES: To examine the development of coronary artery lesions in Kawasaki disease, we assessed the functional behavior and morphology of coronary arteries by intravascular ultrasound. BACKGROUND: Long-term follow-up studies of patients with Kawasaki disease have demonstrated the development of localized coronary stenoses even after aneurysms have regressed. It is also possible that angiographically normal coronary segments in patients with this disease may retain histologic changes. METHODS: Twenty-three patients followed up by serial coronary angiography were examined at a mean age +/- SD of 14.9 +/- 2.9 years. The thickness of the intima-media complex was measured by intravascular ultrasound (30 MHz; 3.5 or 4.3 F; 1,800 rpm). Coronary reactivity to nitroglycerin was determined by measuring percent changes in cross-sectional coronary artery area after intracoronary injection (7 microgram/kg body weight) of this agent. RESULTS: A remarkably thickened intima-media complex was observed at the sites with persisting (0.54 +/- 0.20 mm, n = 19) and regressed (0.84 +/- 0.40 mm, n = 23) aneurysms. Mild thickening of the intima-media complex was often observed even in angiographically normal segments (0.22 +/- 0.05 mm, n = 31), in the left main coronary artery (0.47 +/- 0.15 mm, n = 20) and at normal branches (0.36 +/- 0.09 mm, n = 13). Coronary reactivity to nitroglycerin was significantly lower at the sites of regressed aneurysms (12.8 +/- 6.6%, n = 9) than in normal segments (32.8 +/- 10.9%, n = 13, p < 0.01), indicating the presence of functional impairment at the sites with regressed aneurysms. Decreased nitroglycerin reactivity was also observed in some segments without evidence of aneurysm. CONCLUSIONS: These results indicate that in patients with Kawasaki disease the coronary disease accompanying impaired reactivity to nitroglycerin is present at the sites of regressed aneurysms as well as in angiographically normal coronary segments. We suggest that these sites with morphologic and functional abnormalities are related to the development of significant stenosis.

Adolescent↗