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Biomedical subjects

H Kamiyama

Publications and source records attributed to H Kamiyama.

At least 55 records · Page 3Linked to original sources
PubMed1995

Surgical treatment of childhood moyamoya disease--comparison of reconstructive surgery centered on the frontal region and the parietal region.

Indirect revascularization procedures centered on the parietal region, such as encephalo-myo-arterio-synangiosis (parietal synangiosis) and direct procedures centered on the frontal region using both the anterior and the posterior branches of the superficial temporal artery (STA), such as STA to middle cerebral artery anastomosis combined with encephalo-duro-arterio-myo-synangiosis (frontal anastomosis) were compared in childhood moyamoya disease patients. The parietal synangiosis group consisted of 10 sides in five patients, and the frontal anastomosis group consisted of 30 sides in 15 patients. The development of postoperative collateral circulation was assessed by external carotid angiography, the neurological outcome was monitored for 2 years after surgery, and the intelligence quotient (IQ) was measured at least 6 months after surgery. Frontal anastomosis achieved superior results compared to the parietal synangiosis assessed by development of collateral circulation, in particular to the orbitofrontal artery, the prefrontal artery, and the precentral artery (p < 0.01), and reduction in the incidence of ischemic attacks, such as transient ischemic attacks (p < 0.05). The mean IQ in the frontal anastomosis group was higher than that in the parietal synangiosis group. Vascular reconstruction centered on the frontal region utilizing both the anterior and posterior branches of the STA is more efficacious than only synangiosis centered on the parietal region.

Arteriovenous Anastomosis↗
PubMed1994

Familial occurrence of moyamoya disease. Magnetic resonance angiography as a screening test for high-risk subjects.

The authors report four cases of familial occurrence of moyamoya disease. Although the pathogenesis of moyamoya disease is not clear, there is extensive evidence that this disease has a tendency to show multifactorial inheritance. Therefore, a screening test for those at high risk, i.e., who have a moyamoya patient among their blood relatives, is clinically important. Magnetic resonance angiography (MRA) successfully revealed abnormal findings specific to moyamoya disease in members of the four probands families. MRA is a powerful and noninvasive way of detecting individuals at high risk of developing moyamoya disease.

Anastomosis, Surgical↗
PubMed1994

Ventricular unloading and improvement in left ventricular function after angiotensin converting enzyme inhibition with enalapril in patients with chronic congestive heart failure.

To clarify how angiotensin converting enzyme inhibition affects left ventricular function through ventricular unloading, ventricular wall stress, ventricular volumes, and other cardiac indices and exercise tolerance were evaluated in 17 patients with mild to moderate chronic congestive heart failure before and after 3 months of treatment with enalapril. Echocardiographic examination revealed that treatment with this angiotensin converting enzyme inhibitor resulted in significant reductions in end-systolic wall stress (117 +/- 25 to 89 +/- 28 g/cm2, p < 0.01) and left ventricular volume indices (end-diastolic: 163 +/- 56 to 143 +/- 60; end-systolic 99 +/- 51 to 77 +/- 57 ml/m2 p < 0.01). Ejection fraction (42 +/- 11 to 48 +/- 13%, p < 0.01) and systolic blood pressure/end-systolic volume (SBP/ESV; 1.06 +/- 0.30 to 1.33 +/- 0.48 mmHg/ml, p < 0.01) were both increased. By radionuclide ventriculography, ejection fraction and peak ejection rate (2.30 +/- 0.74 to 2.80 +/- 0.76 EDV/sec, p < 0.01) were increased, while time to peak ejection, time to peak filling, and peak filling rate were unchanged. Heart rate and double product at exercise were decreased and delta EF was significantly increased (-1.4 +/- 4.1 to 1.6 +/- 4.4%, p < 0.02). The decrease in end-systolic wall stress was consistently related to both the increase in ejection fraction and SBP/ESV, while the decrease in end-diastolic volume was related only to SBP/ESV and not to ejection fraction. Furthermore, there was a direct relationship between the decrease in systolic wall stress and the decrease in end-diastolic volume.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

Temporary neurological deterioration caused by hyperperfusion after extracranial-intracranial bypass--case report and study of cerebral hemodynamics.

A 64-year-old female with occlusion of the left internal carotid artery (ICA) developed temporary neurological deterioration after superficial temporal artery to middle cerebral artery anastomosis. Preoperative single photon emission computed tomography (SPECT) showed marked reduction of the cerebral perfusion reserve in the left ICA territory. She suddenly developed aphasia 18 hours after operation. Follow-up SPECT revealed temporary hyperperfusion in the left temporal lobe, strongly suggesting that this unusual complication resulted from bypass flow into the brain tissue with chronic severe ischemia and impaired autoregulation.

Aged↗
PubMed1993

The cerebrospinal fluid in patients with moyamoya disease (spontaneous occlusion of the circle of Willis) contains high level of basic fibroblast growth factor.

The level of basic fibroblast growth factor (bFGF) in cerebrospinal fluid (CF) was measured by an EIA in 15 patients with moyamoya disease, in 11 patients with atherosclerotic occlusive disease, and in 8 patients with spinal disc disease. In the moyamoya patients, bFGF was found in 13 out of 15 CF samples with a mean value of 101 pg/ml. However, bFGF was detected in only 4 out of 11 patients with atherosclerotic disease with a mean of 8 pg/ml. In all the patients with disc disease, bFGF was not detected. The elevated level of bFGF may play a crucial role in the pathogenesis of moyamoya disease.

Adult↗
PubMed1993

Distal ligation and revascularization from external carotid to vertebral artery with radial artery graft for treatment of extracranial vertebral artery dissection. Report of a case.

We present a case of dissection of the extracranial vertebral artery with prominent occipital pain and elements of the lateral medullary syndrome. Arteriography showed a string and pearl sign. Magnetic resonance imaging allowed visualization of an intramural thrombus associated with a narrow vascular lumen. The distal portion of the diseased artery was ligated and vascular reconstruction using an interposed radial artery graft was performed. Pathological studies confirmed the diagnosis. The diagnostic roles of angiography and magnetic resonance imaging, and therapeutic strategies are discussed.

Adult↗
PubMed1993

Longitudinal changes in proton magnetic resonance spectroscopy in cerebral infarction.

BACKGROUND AND PURPOSE: Proton magnetic resonance spectroscopy has revealed changes in lactate and N-acetyl-aspartate in acute cerebral infarction. However, the details of these drastic changes and subsequent chronic changes have not been clarified. The purpose of this study was to disclose longitudinal changes in spectra seen in proton magnetic resonance spectroscopy. METHODS: Six patients with completed cerebral infarction were examined longitudinally with localized proton magnetic resonance spectroscopy. RESULTS: (1) In the acute stage (within 2 days after onset), two drastic changes were observed: N-acetyl-aspartate decreased rapidly and severely within 2 days after onset, and lactate increased immediately and reached a high level in the acute stage after onset. (2) In the chronic stage (more than 1 month after onset), two features were observed: lactate, which had increased in the acute stage, remained high for more than 1 month, and other signals such as those of N-acetyl-aspartate, choline, and phosphocreatine/creatine decreased dramatically. CONCLUSIONS: These results suggest that N-acetyl-aspartate and lactate as revealed by proton magnetic resonance spectroscopy can be useful indicators of the ischemic damage to the brain in clinical cases of cerebral infarction.

Adult↗
PubMed1993

Acetazolamide test in detecting reduced cerebral perfusion reserve and predicting long-term prognosis in patients with internal carotid artery occlusion.

In a series of 32 patients with internal carotid artery occlusion, regional cerebral blood flow (rCBF) and regional cerebral vasoreactivity (rCVR) were measured by xenon-133 single photon emission computed tomography and the acetazolamide test. We evaluated its usefulness in detecting the reduced cerebral perfusion reserve and predicting long-term prognosis. All Type 1 patients (normal rCBF and rCVR) were medically treated and experienced no recurrent ischemic attack. Cerebral hemodynamics remained unchanged. Type 2, 3, and 4 patients underwent superficial temporal artery-middle cerebral artery double anastomosis, if they consented to surgery. All Type 2 (normal rCBF and reduced rCVR) and Type 3 (reduced rCBF and rCVR) patients, who underwent surgery, showed no further ischemic attacks, as well as long-term normalization of rCVR, although long-term rCBF normalization was obtained in only three of seven Type 3 patients. Cerebral hemodynamics remained unchanged in Type 4 patients after surgery. In follow-up periods, major completed stroke occurred in all 3 Type 2 and Type 3 patients who were medically treated. These results suggest that the acetazolamide test is valuable in assessing the cerebral perfusion reserve and predicting long-term prognosis in patients with internal carotid artery occlusion, although further long-term or randomized studies are needed.

Acetazolamide↗
PubMed1993

Visualization of the ostium of an arteriotomy in bypass surgery.

Visualization of the ostium of an arteriotomy by staining it blue with methylrosaniline chloride (pyoctaninum blue) in anastomotic bypass surgery for children with moyamoya disease is described. This technique enables surgeons to create an anastomosis more precisely and quickly. No adverse effects were observed.

Anastomosis, Surgical↗
PubMed1993

Quantitative evaluation of the shape and the elasticity of repaired cleft lip.

Tight lip in repaired cleft lip patients with or without cleft palate (CL[P]) has been discussed as one of the causal factors of maxillary growth retardation and malocclusion. The purpose of this study was to evaluate the shape and the elasticity of repaired cleft lip quantitatively. Forty-one Japanese CL(P) patients were examined. Fifty-four noncleft patients under orthodontic treatment were used as a control group. An apparatus to stretch the anguli oris bilaterally was devised and the extensibility of the lip was measured to evaluate lip elasticity. Standardized photos of the lips were taken to examine lip shape. CL(P) patients showed poor elasticity of the lip. This trend was more apparent in bilateral CL(P) patients than in unilateral CL(P) patients. The upper lip of CL(P) patients was significantly shorter in vertical height. These results clearly demonstrated the tightness and shortness of the repaired lip in CL(P) patients.

Adolescent↗
PubMed1993

Technetium-99m-labeled recombinant tissue plasminogen activator for the imaging of emboli in vivo.

Tissue-type plasminogen activator (t-PA) effectively lyses active thrombus by direct action. Recombinant t-PA (rt-PA) was labeled with technetium-99m (99mTc) to investigate the in vivo binding to fibrin clots in a feline cerebral embolism model created by insertion of an artificial fibrin clot within the carotid artery. 99mTc-rt-PA administered intravenously provided clearer imaging of clots after priming with cold rt-PA, with uptake peaking 5-10 minutes after the injection. 99mTc-labeled human serum albumin was not retained at clot sites. Systemically administered 99mTc-rt-PA binds to fibrin clots within carotid arteries in our feline model. Our results suggest that the interaction of intrinsic plasminogen activator inhibitors with extrinsically administered rt-PA may regulate the demonstration of a clot, although the precise mechanism is unclear.

Animals↗
PubMed1993

Cerebral blood flow in children with spontaneous occlusion of the circle of Willis (moyamoya disease): comparison with healthy children and evaluation of annual changes.

Changes in the mean cerebral blood flow (mCBF) with growth in normal children (1-20 years old) were evaluated, and compared to serial mCBF changes in children with spontaneous occlusion of the circle of Willis (moyamoya disease) after vascular reconstructive surgery. mCBF gradually decreased with growth in control children. Preoperative mCBF was similar or decreased in moyamoya disease patients with transient ischemic attack, and slightly decreased in those with cerebral infarction. Postoperative mCBF gradually decreased similarly to physiological changes with growth in controls. These results suggest that changes with age should be considered when preoperative and long-term cerebral hemodynamics are evaluated in children with moyamoya disease.

Age Factors↗
PubMed1993

Clinical application of angioscopy during carotid endarterectomy for patients with internal carotid artery stenosis.

The accuracy of angioscopy in detecting atherosclerotic changes, such as plaque, ulcer, and mural thrombus, in the extracranial cerebral arteries was evaluated during carotid endarterectomy by comparison with angiographic and operative findings. Ten patients with internal carotid artery stenosis underwent intraoperative angioscopy during surgery. After clamping the carotid bifurcation, intra-arterial atherosclerotic lesions were observed with an angioscope (0.8 or 1.4 mm outer diameter) inserted through a small incision in the common carotid artery. Angioscopic findings correlated well with both angiographic and operative findings in six patients, and provided additional information in two patients, such as organized thrombi within the ulcer and mural thrombi. Angioscopic findings were quite different to those from angiograms in two patients. In one, an ulcer on angiograms was false positive, and in the other, false negative. These findings were confirmed intraoperatively. Our results suggest that preoperative carotid angioscopy is of great value in detecting ulcers more accurately than angiography, and in selecting candidates for carotid endarterectomy, although further development of equipment is needed.

Adult↗
PubMed1993

[Analysis of cerebral blood flow dynamics and evaluation of extracranial-intracranial arterial bypass function using magnetic resonance angiography with presaturation pulse sequence].

Magnetic resonance (MR) angiography was applied to the study of blood flow dynamics and evaluation of extracranial-intracranial arterial bypass function in patients who had received bypass surgery. Three-dimensional gradient-echo acquisitions with selective presaturation of individual vessels were used to determine the direction of blood flow. Presaturation causes signal loss within the territory supplied by the presaturated artery, without affecting vessels not coursing through the presaturation slab. The patency of arterial bypass graft could be demonstrated as properly with MR angiography as with conventional angiography. In addition to that, MR angiography with presaturation pulse clearly demonstrated the direction of blood flow and the territory supplied by arterial bypass graft. The results were correlated with those from transcranial Doppler sonography and conventional angiography. We concluded that MR angiography is a noninvasive useful method for the evaluation of dependency on post-surgical collaterals and bypass function.

Aged↗
PubMed1993

[Usefulness and limitation of MR imaging and MR angiography in diagnosis of juvenile moyamoya disease].

Magnetic resonance (MR) images and MR angiograms (MRA) were studied in 20 childhood cases of moyamoya disease. Both MRI and MRA successfully demonstrated moyamoya vessels in the basal ganglia in all cases, with a positive but not definite correlation to the conventional angiographic findings. MRI depicted the stenotic and occlusive lesions of the carotid fork and horizontal portion of the middle cerebral artery effectively. MRA demonstrated some lesions which even MRI failed to prove, but it tended to overestimate the lesions. Post-operative state of collateral flow and the patency of EC-IC bypass graft could be evaluated as accurately with MRA as with conventional angiography, although MRA was limited in spatial resolution and evaluation of flow direction. In conclusion, MRI and MRA were considered to be useful in the diagnosis of moyamoya disease in stage 3 and 4, but less effective in the evaluation of its angiographical stage.

Child↗
PubMed1993

[Diagnosis of intracranial occlusive vascular disease and evaluation of extracranial-intracranial (EC/IC) arterial bypass using three-dimensional magnetic resonance angiography].

The three-dimensional time-of-flight (TOF) magnetic resonance angiograms (MRA) were studied to evaluate its accuracy in the assessment of the intracranial carotid occlusive lesions, collateral circulation and also the patency of extracranial-intracranial (EC/IC) arterial bypass surgery. All occlusive lesions of the intracranial major arteries seen in conventional angiograms were revealed clearly with MRA. However MRA had its practical limitation in the evaluation of the leptomeningeal anastomosis (collateral circulation) probably due to the deterioration of contrast in its slow flow and saturation effect of the magnetization. In addition to that, MRA often exaggerated the severity of the stenotic lesions, mostly in severe cases. The post-operative state of collateral flow and the patency of EC/IC bypass could be evaluated as properly with MRA as with conventional angiography, although MRA was limited in spatial resolution and evaluation of flow direction. In conclusion, MRA was considered t be a reliable non-invasive modality as a screening examination for the evaluation of the carotid occlusive disease and as the follow-up study of the post-operative patients with EC/IC bypass surgery.

Carotid Artery Diseases↗
PubMed1992

Distal aneurysms of the superior cerebellar artery and posterior inferior cerebellar artery feeding an associated arteriovenous malformation: case report.

The authors report a case of two distal aneurysms of the cerebellar arteries, one arising from the vermian branch of the posterior inferior cerebellar artery, the other arising from the hemispheric branch of the superior cerebellar artery, and both feeding an associated arteriovenous malformation (AVM). The aneurysm of the distal posterior inferior cerebellar artery was considered the source of a cerebellar hemorrhage because of the location of a hematoma in the cerebellar vermis. The life-threatening hematoma was evacuated in an emergency operation 6 hours after the acute onset of symptoms. The cerebellar aneurysms and the AVM were clipped or extirpated successfully after the patient's condition improved. The association of two rare types of aneurysms with an AVM strongly supports the theory that increased hemodynamic stress derived from the AVM plays an important role in aneurysm formation. The authors think that one should operate on the symptomatic lesion first or both the aneurysm and the AVM in the same operative procedure.

Aged↗