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Biomedical subjects

K Miyahara

Publications and source records attributed to K Miyahara.

At least 37 records · Page 2Linked to original sources
PubMed2001

Arteriosclerosis in the influx and intravisceral arteries of the liver, kidney and lung of WHHL rabbits.

We performed a histopathological investigation on arteriosclerotic development in the influx and intravisceral arteries of the liver, kidney and lung of male WHHL rabbits. In the influx arteries of these organs, we observed severe atherosclerotic vascular lesions with high-grade luminal stenosis. In the intravisceral arteries of the liver and kidney, no arteriosclerotic lesions were observed. However, in the intrapulmonary arteries, we recognized severe atherosclerotic vascular changes with high-grade stenosis or total obstruction of the lumen in some middle to large sized pulmonary arteries. These observations indicate that the development of arteriosclerosis in parenchymatous organs differs, and that some organs are predisposed to arteriosclerosis formation.

Animals↗
PubMed2001

[Spontaneous dissection of the anterior cerebral artery presenting subarachnoid hemorrhage and cerebral infarction: a case report].

A case is reported of anterior cerebral artery dissecting aneurysm presenting with subarachnoid hemorrhage and cerebral infarction. A 50-year-old man presented with sudden onset of weakness of the left lower limb was admitted to our hospital. CT scan on admission showed a subarachnoid hemorrhage in the interhemispheric fissure and CT on the 6th day demonstrated a cerebral infarction on the right medial frontal lobe. A carotid angiogram 12 hours after the onset showed no aneurysmal lesion, but, the angiogram repeated 11 days after the onset revealed an aneurysmal dilatation with distal narrowing at the right A2-A3 segment. To prevent rebleeding, we performed a wrapping procedure through the interhemispheric route on the 18th day after onset. The postoperative course was uneventful. We reviewed 27 previously reported cases with symptomatic dissecting aneurysm confined to the anterior cerebral artery.

Aortic Dissection↗
PubMed2001

[Extraction of di-2-ethylhexyl phthalate from a cardiopulmonary bypass circuit].

We measured levels of di-2-ethylhexyl phthalate (DEHP) in a priming solution of a cardiopulmonary bypass circuit. The circuit consisted of a venous reservoir, an oxygenator, and polyvinyl chloride (PVC) tubes. Eight circuits were used in this study. In 4 circuits a heparin-coating PVC tube was used and, in the others, a non-coating PVC tube. After they were primed with 1,500 ml of saline, the saline was circulated for 30 minutes at a rate of 6 l/min at 42 degrees C. Another four samples were collected directly from the saline in a polyethylene container as a control. Then the concentrations of DEHP in them were determined by means of gas chromatography. No detectable DEHP was found in controls. But, a small amount was detected in the saline from the circuits (2.75 +/- 4.27 ppb, and 3.75 +/- 4.99 ppb, respectively). DEHP was considered to be leached from the circuit to the priming solution because the tubes were made of PVC containing DEHP as a plasticizer. We suppose the DEHP concentration is probably at a safe level. However, the data on the endocrinologically toxic level of blood DEHP are insufficient. Therefore, the use of plastic in a circuit may require closer scrutiny to determine whether DEHP leached from PVC contributes to exposure to xenoestrogens.

Cardiopulmonary Bypass↗
PubMed2001

Bladder transplantation in rats using FK-506.

PURPOSE: We created viable bladder tissue by transplantation with immunosuppression. MATERIALS AND METHODS: For bladder transplantation the bladder of newborn Brown-Norway rats was excised and each was transplanted into a pouch created in the distal omentum of a 5-week-old Lewis rat. In 15 group 1 rats no immunosuppressive agent was used. In 20 group 2 rats 0.6 mg./kg. FK-506 daily were given intramuscularly until a predetermined day of harvest. Recipient rats were sacrificed on day 3, 5, 7 or 14 after bladder transplantation, and the bladder grafts were harvested and formalin fixed. Hematoxylin and eosin staining was done to examine bladder graft survival and the degree of rejection, and immunohistochemical testing was performed for assessing the vesical nervous system. In 5 rats in the control group bladder augmentation was performed by anastomosing the bladder graft to the native bladder. Each augmented bladder was harvested 21 days later for histopathological assessment. RESULTS: Overall bladder graft survival was 96.4%. Each successfully transplanted bladder graft appeared macroscopically as a thin walled cyst. In group 1 all bladder grafts showed rejection with cellular infiltration. In group 2 there was mild rejection in 5 rats and no evidence of rejection in the remaining 15. All group 2 bladder grafts had intact nerve distribution. Bladder augmentation was successful in all 5 cases and the mucosa was normal throughout each augmented bladder. CONCLUSION: Because FK-506 successfully prevents rejection, our technique would appear to have the potential for creating viable bladder tissue that may be used for bladder augmentation in cases of vesical exstrophy or neurogenic bladder.

Animals↗
PubMed2001

[Reoperation for late postoperative right ventricular outflow tract obstruction].

Between February 1993 and July 2000, 18 patients with a mean age of 7.9 years underwent re-operation for critical stenosis of the right ventricular outflow tract. Their diagnoses of these patients included tetralogy of Fallot (n = 7), transposition of the great arteries (n = 6), truncus arteriosus communis (n = 3), and double outlet right ventricle with pulmonary stenosis (n = 2). The first operations were extracardiac conduit operations (n = 9), arterial switch operations (n = 6) and patch reconstruction of the right ventricular outflow tract (n = 3). At re-operation, the right ventricular outflow tract obstruction was released completely and reconstructed using a monocusp ventricular outflow patch (n = 14), valved pericardial roll (n = 2), or bovine pericardial patch sparing the native pulmonary valve annulus (n = 2). There were no early deaths, although one patient died of arrhythmia 2.6 years after re-operation. The pressure gradient across the right ventricular outflow tract, right ventricular systolic pressure, and right ventricle to systemic systolic pressure ratio were satisfactorily relieved (84.3 +/- 19.0 vs. 16.7 +/- 19.7 mmHg, 109.2 +/- 20.5 vs. 48.7 +/- 16.7 mmHg, 0.92 +/- 0.25 vs. 0.43 +/- 0.16; p < 0.001, p < 0.001, p < 0.001, respectively). The right ventricular end-diastolic volume index and right ventricular ejection fraction were also improved (166.3 +/- 85.2 vs. 105.6 +/- 28.8% of normal, 38.3 +/- 12.6 vs. 50.9 +/- 8.8%; p < 0.05, p < 0.005, respectively). Re-operation should be done before the development of marked right ventricular dysfunction, while it can still be performed at a low risk with satisfactory results.

Child↗
PubMed2001

[A case of diffuse alveolar hemorrhage developing after open heart surgery].

A 47-year-old man was receiving anticoagulant therapy after coronary artery bypass grafting and mitral valve plasty. A chest roentgenogram disclosed alveolar infiltrates throughout both lung fields 6 months postoperatively. Lung biopsy specimens showed the presence of hemosiderin-laden macrophages in the alveolar spaces, establishing a diagnosis of diffuse alveolar hemorrhage. Anticoagulant therapy may have caused the hemorrhage, because the patient had no immunologic disorder or renal disease. The shadows completely disappeared after steroid therapy and discontinuation of anticoagulant therapy. Diffuse alveolar hemorrhage should be considered, when extensive infiltrates develop on chest roentgenogram in patients receiving anticoagulant therapy after open heart surgery. Lung biopsy is essential, when a bronchoalveolar lavage fails to diagnose the disease.

Cardiac Surgical Procedures↗
PubMed2001

[Successful treatment of a patient with low pressure syndrome associated with gait disturbance].

The authors report an unusual case of low intracranial pressure (ICP) syndrome that was successfully treated by the placement of an anti-siphon device (ASD). This 36-year-old male had suffered suprasellar germinoma with hydrocephalus and had had a V-P shunt following radiotherapy. Sixteen years later he developed gait disturbance and somnolence and MRI demonstrated a small lateral ventricle as well as a diffuse dural enhancement. A lumbar tap revealed a low ICP of 12 mmH2O. Because of this, an ASD was placed in the patient. Postoperatively, his symptoms of gait and consciousness disturbance improved. Typical clinical findings of low ICP syndrome such as headache were not observed in this case. To our knowledge, no symptom of gait disturbance with low ICP has been reported previously. We present an interesting case of low ICP syndrome with gait disturbance and discuss the mechanism of the symptoms. Symptoms of this patient were due at first to brain ischemia. After convulsion and consciousness disturbance due to low intracranial pressure, the symptoms increased in strength until gait disturbance occurred. The possibility is suggested that gait disturbance in this patient was due both to brain ischemia and low intracranial pressure.

Adult↗
PubMed2001

[Surgical reconstruction for radiation-induced extracranial vertebral artery stenosis: a case report].

We report a case of symptomatic extracranial vertebral artery stenosis after radiation therapy. This 49-year-old female received radiation therapy to the neck for nasopharyngeal carcinoma 11 years earlier, was admitted because of continuous dizziness and a floating sensation. Magnetic resonanse imaging showed no abnormalities, but an aortography demonstrated complete occlusion of the right common carotid artery as well as occlusion of the right vertebral artery and severe stenosis of the left vertebral artery at its origin, which was presumed to be the result of previous radiation therapy. Percutaneous transluminal angioplasty (PTA) for the left vertebral artery was performed using conventional balloon treatment, which resulted in wall dissection. Because of this, she underwent end-to-side vertebral artery to subclavian artery transposition, and she has had no further ischemic events science that time. PTA has been successfully performed as the first treatment of choice for vertebral artery stenosis, but surgical reconstruction can be a therapeutic management of choice for cases of failed PTA.

Female↗
PubMed2000

Evidence for the presence of 1,2-cyclic acetal type sn-glycero-3-phosphoethanolamines in the sea anemone, Actiniogeton sp.

Five 1,2-cyclic acetal-type sn-glycero-3-phosphoethanolamines (CGPE) were isolated in a pure state from the sea anemone, Actiniogeton sp. (Coelenterata). Their structures, including the absolute configurations, have been determined on the basis of chemical and spectral data to be so-called Feulgen's acetalphosphatides, which have been regarded as artifacts derived from original plasmalogens. We examined whether these CGPE are intact constituents in the animal tissues and obtained reliable confirmation that CGPE are normally present in the sea anemone.

Animals↗
PubMed2000

Tubed latissimus dorsi musculocutaneous flaps for esophageal replacement in puppies: long-term follow-up.

PURPOSE: The aim of this study was to show that a tubed latissimus dorsi musculocutaneous flap (tubed LDMCF) may be useful for treating circumferential esophageal defects. METHODS: A segment of esophagus 3 vertebrae long was excised through a right thoracotomy in each of 6 puppies, and a tubed LDMCF was interposed between the cut ends of esophagus. The puppies were sacrificed after a mean follow-up period of 6.6 years. The tubed LDMCF was examined histologically. Functional integrity was assessed using barium meal and endoscopy before sacrifice. RESULTS: All puppies survived and grew normally on a normal diet, although 4 vomited occasionally. There was smooth passage of barium through the tubed LDMCF without stenosis, although endoscopy showed regrowth of hair. Histologically, no metaplasia, dysplasia, or malignancy was observed in any tubed LDMCF. CONCLUSIONS: The tubed LDMCF is technically safe, obviates the necessity for laparotomy, and long-term follow-up would suggest that it is histologically stable. Thus, it could become an alternative procedure for bridging esophageal defects.

Animals↗
PubMed2000

Idiopathic gastric perforation in neonates and abnormal distribution of intestinal pacemaker cells.

BACKGROUND/PURPOSE: The etiology of idiopathic gastric perforation (IGP) in neonates is unclear. Interstitial cells of Cajal (ICC) express tyrosine kinase receptor C-kit, and act as gastrointestinal pacemaker cells. Stem cell factor (SCF) is a C-kit ligand and plays an important role in immune system homeostasis in the gastrointestinal tract. The authors hypothesized that abnormal distribution of ICC or SCF in the gastric wall (ie, abnormal motility or impaired immunity) could predispose the stomach to IGP. METHODS: Stomachs obtained at postmortem from neonates who died of IGP (n = 7) and other causes (control group; n = 10) were used. Biopsy sections were taken at random from various sites in the stomach, including macroscopically intact areas, and labeled immunohistochemically using antibodies to C-kit(a marker for ICC) and SCF. RESULTS: In all control specimens, ICC were present between the muscle layers and around the myenteric plexuses of the stomach wall. In contrast, ICC were absent in all biopsy sections from 3 of the 7 IGP stomachs. In the remaining 4 IGP stomachs, there were fewer ICC in the muscle layers compared with controls, and ICC were absent around the myenteric plexuses. The distribution of SCF immunoreactivity in IGP and control specimens was similar. CONCLUSION: The findings suggest that a lack of ICC (ie, gastric hypomotility) may be implicated in the etiology of IGP in neonates.

Analysis of Variance↗
PubMed2000

Hemodynamic effects of intravenous administration of olprinone hydrochloride on experimental pulmonary hypertension.

To examine acute effects of olprinone hydrochloride (CAS 106730-54-0, Coretec) on pulmonary hypertension, hypoxic pulmonary hypertension was produced in 6 adult Beagle dogs. Using this pulmonary hypertension model, single intravenous bolus injections of olprinone at doses of 10, 30 and 100 micrograms/kg were administered at 5-min intervals and hemodynamic parameters were evaluated. Heart rate increased at doses of 30 and 100 micrograms/kg, but did not change at a dose of 10 micrograms/kg. Mean aortic pressure, mean pulmonary arterial pressure, pulmonary vascular resistance and systemic vascular resistance and right ventricular stroke work index did not change at doses of 10 and 30 micrograms/kg, but they decreased significantly at a dose of 100 micrograms/kg. On the other hand, cardiac index and the first derivative value of the left ventricular pressure did not show significant change at all doses. These results indicate the vasodilating effects on peripheral and pulmonary vessels in hypoxic model at high doses of olprinone. Its application in right heart failure accompanied by pulmonary hypertension therefore is expected to yield promising results.

Animals↗
PubMed2000

Optically active N-acetyldopamine dimer of the crude drug "Zentai," the cast-off shell of the Cicada, Cryptotympana sp.

Two optically active N-acetyldopamine dimers together with four phenolic monomers were isolated from the crude drug "Zentai," a cast-off shell of the cicada of Cryptotympana sp. (Cicadidae). The former two were 2-(3',4'-dihydroxyphenyl)-1,4-benzodioxane derivatives carrying substituents at the 3 and 6 (or 7) positions, which are known to be components of sclerotized insect cuticles. Their structures including absolute configurations were determined on the basis of NMR and circular dichroism (CD) spectroscopic data.

Animals↗
PubMed2000

Fourteen-year survival in a case of ventricular septal perforation after myocardial infarction.

We treated a case of ventricular septal perforation (VSP) who survived for 14 years after myocardial infarction. Nine years after the onset of myocardial infarction, an apparent cardiac murmur was discovered by chance, and following further examination, the patient was diagnosed as having VSP. The patient is still in the NYHA functional class I, and requiring no surgical treatment. In general, the prognosis of myocardial infarction complicated with VSP is so poor that there have only been 14 reported cases of long survival without surgical treatment. Among these patients, only 2 survived for more than 10 years. The present case is extremely rare, and evidently is the longest living survivor with this condition yet reported.

Aged↗
PubMed2000

[Evaluation of cardiac autonomic nerves by iodine-123 metaiodobenzylguanidine scintigraphy and ambulatory electrocardiography in patients after arterial switch operations].

The autonomic cardiac nerves reach the heart after passing through the vicinity of the aortic root and the pulmonary trunk. The arterial switch operation (ASO) completely transects the ascending aorta and the pulmonary trunk. Therefore, this surgical procedure virtually denerves the heart. Cardiac sympathetic denervation and reinnervation were evaluated in patients after ASO using iodine-123 metaiodobenzylguanidine (MIBG) myocardial scintigraphy and parasympathetic denervation and reinnervation using ambulatory electrocardiography [Holter electrocardiogram (ECG)]. MIBG scintigraphy was performed in 14 patients who underwent ASO (ASO group) and 3 patients who underwent other open heart surgery (control group). All patients in the ASO group underwent the operation in the neonatal or infantile period. Planar and single photon emission computed tomography (SPECT) images of the myocardium were obtained. Defect score was determined by the SPECT images as a semi-quantitative index. The mean interval between ASO and MIBG scintigraphy was 25.6 +/- 14.6 months. Holter ECG was also performed in 14 patients in the ASO group and 19 age-matched normal children. The Holter ECGs were plotted on a Lorenz plot. The H index, which is related to vagal tone for the cardiovascular system, was calculated from the R-R intervals. The mean interval between the ASO and Holter ECG was 8.3 +/- 9.7 months. MIBG scintigraphy in the control group demonstrated an almost normal homogeneous tracer uptake, but showed extremely reduced tracer uptake and significantly higher defect score in the ASO group. The extent and degree of the reduction of MIBG uptake improved with time after the ASO. The heart-to-mediastinum MIBG count ratio tended to increase with time. The H index of the ASO group was lower than that of normal children (< 12 months: Control group 0.0280 +/- 0.0068 vs ASO group 0.0219 +/- 0.0083), and gradually increased with time (1-3 years: 0.0470 +/- 0.0157 vs 0.0314 +/- 0.0124). These results indicate that MIBG scintigraphy reflects the presence of sympathetic denervation and the possibility of reinnervation after ASO, and that H index reflects the presence of parasympathetic denervation and the possibility of reinnervation after ASO. These are simple and useful methods for assessing the extent and degree of autonomic denervation and reinnervation.

3-Iodobenzylguanidine↗
PubMed2000

Repair of leaking postinfarction ventricular septal defect under circulatory arrest via left thoracotomy.

We treated a 60-year-old woman for postinfarction ventricular septal defect (VSD) and closed it by the infarction exclusion method. Postoperatively she was complicated by Candida sternal mediastinitis and residual shunt of VSD. After her sternal infection came under control we repaired the leaking VSD via left thoracotomy under hypothermic circulatory arrest. She recovered well and repair of the leaking VSD under circulatory arrest via left thoracotomy seemed to be a safe and promising alternative for VSD repair.

Blood Vessel Prosthesis Implantation↗
PubMed2000

[Mid-term results of the arterial switch operation for transposition of the great arteries: effect of fresh autologous pericardial patch in preventing postoperative pulmonary stenosis].

To evaluate the differences in patch-materials used to reconstruct the pulmonary artery in arterial switch operation for transposition of the great arteries, we compared mid-term results in 50 consecutive survivors who underwent arterial switch operation. In 35 patients (XP-group), the pulmonary artery was reconstructed using a glutaraldehyde-treated heterologous pericardial patch, while in 15 patients (AP-group) it was reconstructed using a fresh autologous pericardial patch. A W-shaped patch was used in 14 patients of the XP-group. In 21 patients of the XP-group and all those of the AP-group, a square patch was used. The mean length of follow-up has been 94.1 +/- 38.1 months after surgery in XP-group, and 16.7 +/- 11.8 months in AP-group, respectively. Four patients in XP-group required balloon angioplasty for pulmonary stenosis and 5 patients in XP-group underwent reoperation, but no patients in AP-group required balloon angioplasty or reoperation for pulmonary stenosis. The risk factors influencing postoperative pulmonary stenosis (sex, age at surgery, preliminary pulmonary artery banding, patch shape and material) were analyzed by multiple regression analysis. The patch material (heterologous patch) was the only identifiable risk factor for pulmonary stenosis. These data suggest that pulmonary artery reconstruction with an autologous pericardial patch may be effective to prevent postoperative pulmonary stenosis, although the long-term prognosis remains unknown.

Female↗