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H Kamiyama

Publications and source records attributed to H Kamiyama.

At least 37 records · Page 2Linked to original sources
PubMed1999

[Ruptured persistent primitive hypoglossal artery aneurysm: case report].

Persistent primitive hypoglossal artery is less common than persistent primitive trigeminal artery. About one hundred examples of such hypoglossal arteries have been demonstrated by angiography. The origin of persistent primitive hypoglossal artery is the cervical segment of the internal carotid artery, usually at the level of the first to second cervical vertebrae. The artery then enters, with varying degrees of tortuosity, the anterior condyloid (hypoglossal) canal and joints the basilar artery immediately above its lower end. When enlargement of this canal is identified, the presence of a persistent primitive hypoglossal artery should be strongly suspected. The homolateral vertebral artery is frequently hypoplasia. A 66-year-old man was brought to our hospital due to faintness. CT showed thick subarachnoid hemorrhage. Angiography showed that a persistent primitive hypoglossal artery aneurysm was present, but the posterior communicating artery was absent. Right vertebral angiography showed extravasation due to re-rupture of the aneurysm. An operation was performed at day 0 using the left transcondylar approach despite deterioration of SAH grading. Intraoperative re-rupturing occurred and the lower cranial nerves clustered around the aneurysm, so the aneurysm was partially clipped on the dome. The second angiography was carried out at day 10, and there was no vasospasm. Palsy of the lower cranial nerves appeared transiently. A ventricle-peritoneum shunt was required due to normal pressure hydrocephalus, but the patient was discharged with no neurological deficits.

Aged↗
PubMed1998

Pharmacokinetics of erythropoietin in genetically anemic mice.

We examined the pharmacokinetics of recombinant human erythropoietin (rh-EPO) in genetically anemic mice (W/Wv genotype) to clarify its disposition mechanism in hematopoietic injury such as occurs in aplastic anemia. After rh-EPO was administered to W/Wv and control (+/+ genotype) mice once a day for 1 week at different doses, both the hematocrit (Hct) and tissue uptake clearance (CLup) of 125I-rh-EPO by spleen and bone marrow in the femur were estimated on the eighth day. The hematocrit increased on eighth day, depending on the dose administered. Compared with +/+ mice 10 times more rh-EPO was needed in W/Wv mice to produce an almost equivalent pharmacological effect. In +/+ mice, the CLup of 125I-rh-EPO by spleen increased to 4-fold that of controls after treatment with rh-EPO, 4.8 microg/kg, whereas that by bone marrow remained unchanged, irrespective of the dose administered. On the other hand, the increase in both the Hct and CLup in spleen was minimal in W/Wv mice. The CLup by bone marrow and spleen in both types of mice showed saturation with similar Km values (389-619 pM), comparable with the dissociation constant of the EPO receptor. In addition, the Hct correlated with the sum of the CLup by bone marrow and spleen in both types of mice, and the correlation lines were superimposable. These results suggest that the pharmacological receptors govern the saturable tissue uptake not only in normal mice but also in those that are anemic.

Animals↗
PubMed1998

[Clinical effects of sodium ozagrel and urokinase in patients with acute cerebral infarction in the territory of the internal carotid artery].

In this study, the clinical effects were compared between a thromboxane synthetase inhibitor (sodium ozagrel) and a thrombolytic agent (urokinase) in patients with acute cerebral infarction. The subjects consisted of 598 patients admitted on the day of the onset of the cerebral infarction in the territory of the internal carotid artery who showed a low density area on CT images within 5 days. Of these patients, 300 were treated with sodium ozagrel and classified as Group Oz, while the remaining 298 were treated with urokinase and classified as Group Ur. The results were as follows: 1. In group Oz, complete recovery of motor impairment was seen in 209 (69.7%) patients. Complete recovery within 3 weeks after onset was seen in 186 (62.0%) patients. In group Ur, complete recovery of motor impairment was seen in 175 (58.7%) patients. Complete recovery within 3 weeks after onset was seen in 120 (40.3%) patients. Therefore, a higher incidence of complete recovery of the motor impairment was noted in group Oz [p < 0.001: chi 2 test]. Similarly, complete recovery within 3 weeks after onset was more frequent in group Oz [p < 0.001: chi 2 test]. 2. In group Oz, complete recovery was made contribution statistically by Anosognosia (Ag) and unilateral neglect (UN) on admission [multivariate analysis: p < 0.01]. In group Ur, complete recovery was made contribution statistically by Ag (p < 0.01), UN (p < 0.01) and aphasia (p < 0.05). 3. Progressive stroke was observed in 29 (9.5%) patients in the group Oz and in 71 (23.0%) patients in group Ur. There was a higher incidence of progressive stroke in group Ur [p < 0.001: chi 2 test] 4. All patients with progressive stroke had initial evidence of deterioration of neurological deficits within 6 days after the onset in group Oz, and within 5 days after the onset in group Ur. The maximal period from the beginning to the end of the deterioration of neurological deficit was 7 days. 5. In group Oz, progressive stroke was only seen in 29 (29.9%) of the patients who were admitted with motor disturbances and unilateral neglect. In group Ur, progressive stroke was seen in 8 (4.3%) of the 187 patients with motor disturbances without higher cortical dysfunction, in 17 (47.2%) of the 36 patients with motor disturbances and higher cortical dysfunction without unilateral neglect and was seen in 46 (61.3%) of the patients with motor disturbances and unilateral neglect. 6. Hemorrhagic infarction was observed in 14 (4.6%) patients in group Oz and in 31 (10.0%) patients in group Ur. There was a higher incidence of hemorrhagic infarction in group Ur [p < 0.001: chi 2 test]. 7. In group Oz, there was a higher incidence of hemorrhagic infarction among patients with atrial fibrillation (Af) on the ECG [p < 0.001: chi 2 test]. Similarly, in group Ur, hemorrhagic infarction was more frequent among patients with atrial fibrillation (Af) on the ECG [p < 0.001: chi 2 test]. Therefore, sodium ozagrel was clinically more efficient and safer than urokinase in patients with acute cerebral infarction.

Adult↗
PubMed1998

[Advanced gastric cancer curatively resected following combined neoadjuvant chemotherapy--report of a case].

An advanced gastric cancer patient with T3N1M0 successfully underwent a curatively total gastrectomy combined with distal pancreatectomy and lymphnode dissection following ELF-P combined chemotherapy. The patient received two courses of etoposide (75 mg/m2, Day 1-5, i.v.), leucovorin (30 mg/body, Day 2-5, i.v.), 5-FU (500 mg/m2, Day 2-5, i.v.) and CDDP (60 mg/m2, Day 1, i.v.). A partial response for the primary lesion and lymphnode metastasis was obtained, and a successful curative resection of the stomach was performed. No drug adverse responses occurred. The effect of ELF-P chemotherapy was confirmed with grade 1b by histopathological examinations. Neoadjuvant chemotherapy with ELF-P may be useful as an inductive approach for advanced gastric cancer.

Adenocarcinoma↗
PubMed1998

Metabolism of 2(R,S)-1,2-bis(nicotinamido)propane, a new agent with anti-vasospasm activity, in rats and rabbits.

1. The metabolic fate of the new Anti-vasospasm Substance (AVS), 2(R,S)-1,2-bis(nicotinamido)propane (CAS 79455-30-4), was studied using 14C-labelled drug in rats and rabbits by thinlayer chromatography, mass spectrometry and nuclear magnetic resonance. 2. More than 75% of the radioactivity was observed in the urine when 14C-AVS was given intravenously to rabbits and rats, showing that the major route of excretion of AVS and its metabolites is via the kidney. 3. Marked species differences were observed in the metabolism of AVS in rats and rabbits. In rabbits, the major metabolites were 6- or 6'-monopyridone (23.5% of dose), and there were a few minor metabolites such as the mono N- or N1-oxide of two pyridine rings. In rats, however, only approximately 5% of the radioactivity was due to metabolites, mainly the N-oxide. 4. Formation of AVS monopyridone by rabbit liver cytosol was much higher than in rats, and was markedly inhibited by the aldehyde oxidase inhibitor, menadione. The difference between rats and rabbits in oxidase activity giving the AVS monopyridone metabolite correlated well with that measured by the general assay method for aldehyde oxidase. These results suggest that the species difference in AVS metabolism between rats and rabbits is mainly due to the difference in aldehyde oxidase activity, which is involved in formation of the monopyridone.

Aldehyde Oxidoreductases↗
PubMed1998

[Can EC-IC bypass prevent brain ischemia from recurring?].

The effectiveness of extracranial-intracranial arterial bypass (EC-IC bypass) surgery for patients with hemodynamic compromise still remains controversial. In the present study, we evaluated the correlation between the pre- and post-surgical cerebral hemodynamics and long-term prognosis. 28 patients and a subsequent 21 patients (41 men, eight women: mean age 59.9 [S.D. 8.6] years) with reduced cerebrovascular reserve due to steno-occlusive disease of the cerebral major arteries formed the study groups 1 and 2, respectively. Measurement of the mean hemispheric cerebral blood flow (mCBF) and the cerebral vasoreactivity (%mCVR) with an intravenous acetazolamide injection were performed by a 133Xe inhalation method and SPECT. Patients were treated with EC-IC bypass surgery and measurement of mCBF and %mCVR were made again about one month after surgery. The patients were observed for a long period (mean 44.3 months). During the follow-up period, 6 patients experienced recurrent ischemic strokes. The annual incidence of recurrent ischemic stroke was 4.4%. The patients with significantly reduced pre- and post-surgical resting mCBF of the affected hemisphere were at significantly higher risk of recurrent ischemic stroke than the patients with normal mCBF (p < 0.01). The %mCVR of the affected hemisphere rose after surgery.

Adult↗
PubMed1997

Combined revascularization surgery for childhood moyamoya disease: STA-MCA and encephalo-duro-arterio-myo-synangiosis.

We present surgical techniques for optimal revascularization in childhood moyamoya disease. During the past 10 years we performed revascularization surgery for childhood moyamoya disease using direct revascularization with superficial temporal artery to middle cerebral artery (STA-MCA) anastomosis and indirect revascularization of encephalo-duro-arterio-myo-synangiosis (EDAMS) 43 times. Points of this surgery are as follows: (1) craniotomy and dural opening for the most extensive possible exposure of the brain surface, (2) protective manipulation of the STA, temporal muscle and middle meningeal artery, (3) STA-MCA anastomosis to the frontal branch of the MCA to improve cerebral circulation of the frontal lobe using a small branch of the STA, and (4) a small opening in the arachnoid membrane and watertight closure.

Brain Ischemia↗
PubMed1997

Effects of surgical revascularization on outcome of patients with pediatric moyamoya disease.

BACKGROUND AND PURPOSE: We reviewed surgically treated patients with pediatric moyamoya disease and examined whether vasoreconstructive surgeries reduced the risk of recurrent ischemic attacks and changed overall outcomes in terms of the patients' performance and intellectual status. METHODS: Sixty-four hemispheric sides in 34 pediatric moyamoya disease patients who received surgical treatment were examined. We performed superficial temporal artery to middle cerebral artery (STA-MCA) bypass and encephalo-duro-arterio-myo-synangiosis (EDAMS) on 48 sides (combined group) and indirect bypass surgery such as EDAMS on 16 sides (indirect group). These 34 patients were observed postoperatively from 1 to 14 years (mean +/- SD, 6.6 +/- 3.8 years) and were examined for the incidence of recurrent ischemic attack. Of the 34 patients, 23 were followed up for > 5 postoperative years, and their overall outcomes in terms of their performance and intellectual status were determined. RESULTS: Perioperative ischemic events (< or = 2 weeks after surgery) occurred in 5 surgeries (31%) of the indirect group and in 6 (13%) of the combined group (P = NS). The incidence of postoperative ischemic events (> 2 weeks after surgery) was significantly reduced in the combined group (10%) compared with the indirect group (56%; P < .01). Of the 23 patients observed > 5 years, 7 patients (30%) were mentally retarded and regarded as having a fair outcome. CONCLUSIONS: Combined surgery (STA-MCA bypass with EDAMS) for pediatric moyamoya disease was effective in reducing the risk of postoperative ischemic attacks compared with indirect surgery. Surgical revascularization may be effective in preventing intellectual deterioration and improving overall outcome.

Adolescent↗
PubMed1997

Immunological response to repeated administration of recombinant human erythropoietin in rats: biphasic effect on its pharmacokinetics.

We studied changes in the pharmacokinetics of 125I-recombinant human erythropoietin (125I-rh-EPO) after repeated subcutaneous administration once a week for 4 weeks. The plasma level of trichloroacetic acid-precipitable radioactivity after the fourth administration of 125I-rh-EPO was minimal in 8 of 10 rats, whereas in the other two rats, the plasma level was almost the same or somewhat higher than that in control rats that had received the vehicle solution 3 times instead of the first three sequential administrations. Antibody against rh-EPO in serum was detected in all 10 rats receiving multiple administrations of 125I-rh-EPO. However, the binding capacity for 125I-rh-EPO in the latter two rats, assessed by an in vitro serum binding study, was lower than for the other eight rats, suggesting that the antibody level in these two was lower. The effect of intravenous preinjection of various volumes of anti-rh-EPO antiserum on the pharmacokinetics of 125I-rh-EPO was examined. The half-life in the beta-phase was prolonged at lower doses of antiserum. When the pretreatment dose of antiserum was further increased, the half-life in the beta-phase rather shortened and the total body clearance (CL(total) increased. These results suggest that repeated administration of rh-EPO induces the production of antibody against rh-EPO that affects the pharmacokinetics of rh-EPO in a biphasic manner; CL(total) was reduced when a small amount of antibody was produced, and CL(total) was increased when a large amount of antibody was produced.

Animals↗
PubMed1997

Mechanism for the nonlinear pharmacokinetics of erythropoietin in rats.

The contribution of erythropoietin- (EPO) receptors in target tissues, such as bone marrow and spleen, to the nonlinear pharmacokinetics of recombinant human EPO (rh-EPO) was evaluated in rats. The total body clearance after i.v. administration of rh-EPO (0.2-5 microg/kg) decreased as the dose of rh-EPO increased, approaching a plateau at high doses. The uptake clearance of 125I-rh-EPO by the target tissues, bone marrow and spleen, exhibited clear saturation. The Km values ranged from 240 to 450 pM, which are comparable with the reported value for the dissociation constant of EPO binding to EPO-receptors (180 pM) in rat bone marrow cells. A single s.c. administration of a large dose of rh-EPO (1 microg/kg) caused a reduction in tissue uptake clearance of 125I-rh-EPO by bone marrow and spleen (down-regulation). Furthermore, repeated intravenous injection of rh-EPO caused up-regulation of the tissue uptake clearance of 125I-rh-EPO, especially by the spleen, in a dose-dependent manner. Hematopoietic parameters such as hematocrit and hemoglobin concentration were also increased by repeated rh-EPO treatment and significantly correlated with the sum of the tissue uptake clearances in bone marrow and spleen. These findings suggest that the pharmacological receptor could be an important factor in defining the nonlinear pharmacokinetics of rh-EPO.

Animals↗
PubMed1996

Surgical therapy for adult moyamoya disease. Can surgical revascularization prevent the recurrence of intracerebral hemorrhage?

BACKGROUND AND PURPOSE: It is well recognized that revascularization surgery using direct and/or indirect bypass provides effective surgical management for pediatric moyamoya disease. However, surgical treatment of the adult hemorrhagic type remains controversial. In this study, the effect of surgery for adult moyamoya disease was investigated. METHODS: We analyzed 35 patients with adult moyamoya disease (patient age, over 20 years), 24 patients with initial onset of intracerebral hemorrhage, and 11 patients with initial onset of cerebral ischemia who underwent both direct bypass surgery of the superficial temporal artery to the middle cerebral artery anastomosis and indirect revascularization of encephalo-duro-arteriomyo-synangiosis. RESULTS: Of 24 patients with hemorrhagic-type disease, 3 showed rebleeding: of 11 patients with the ischemic type, 2 showed intracerebral hemorrhage after surgery. Overall, 5 of 35 patients (14.3%) had hemorrhage after revascularization surgery (mean follow-up period, 6.4 years). Postoperative angiography revealed that direct anastomosis is effective whereas indirect revascularization is not always effective for adult moyamoya disease. Moyamoya vessels, which are supposed to be responsible for hemorrhage, decreased in 25% of patients. CONCLUSIONS: Revascularization surgery cannot always prevent rebleeding. However, a decrease in moyamoya vessels was induced by surgery, which may reduce the risk of hemorrhage more effectively than conservative treatment. In cases of adult moyamoya disease, direct bypass is particularly important, since the indirect revascularization is not as useful in adult cases as in pediatric cases.

Adult↗
PubMed1996

Evaluation of cardiac sympathetic nervous function by 123I-metaiodobenzylguanidine scintigraphy in insulin-treated non-insulin dependent diabetics with hypoglycemia unawareness.

The association between the lack of adrenergic symptoms during hypoglycemia and myocardial 123I-metaiodobenzylguanidine (MIBG) accumulation was investigated in 12 insulin-treated non-insulin-dependent diabetes mellitus (NIDDM) patients who had no evidence of heart disease. These patients were divided into 2 groups according to the presence (group A) or absence (group B) of adrenergic symptoms during hypoglycemia. Autonomic function tests revealed significantly severe autonomic dysfunction in group B compared to that in group A. Insulin infusion test indicated no significant difference in the catecholamine response between the two groups. 123I-MIBG scintigraphy showed that the heart/mediastinum ratio of MIBG uptake was significantly lower, and scintigraphic defect was greater in group B than in group A. There were no significant differences in the washout rate between the two groups. These results suggested that the lack of adrenergic symptoms during hypoglycemia may be associated with cardiac sympathetic nervous dysfunction in insulin-treated NIDDM patients, and this dysfunction is mainly due to cardiac sympathetic denervation.

3-Iodobenzylguanidine↗
PubMed1995

Cerebral hemodynamics and "re-build-up" phenomenon on electroencephalogram in children with moyamoya disease.

"Re-build-up" phenomenon, induced by hyperventilation, is a characteristic finding on electroencephalogram (EEG) in children with moyamoya disease, and suggests close correlation with cerebral ischemic attack. Its mechanism, however, remains obscure. In this study, we examined the relationship between the cerebral hemodynamics and this phenomenon before and after vascular reconstructive surgery. Regional cerebral blood flow and its reactivity to acetazolamide were analyzed using the xenon-133 inhalation method and single photon emission computed tomography in six children with moyamoya disease. These results were compared with the EEG. Regional vasoreactivity to acetazolamide was significantly lower in "re-build-up" -positive regions than in "re-build-up" -negative regions. Postoperative studies revealed a significant improvement of reactivity in the regions where the "re-build-up" phenomenon disappeared after surgery. These results suggest that the "re-build-up" phenomenon represents a focal reduction of the cerebral perfusion reserve in moyamoya disease.

Acetazolamide↗
PubMed1995

Regional cerebral hemodynamics in childhood moyamoya disease.

Regional cerebral blood flow (rCBF) and its reactivity to acetazolamide were analyzed in a series of 15 cases of childhood moyamoya disease, using the xenon-133 inhalation method and single photon emission CT (SPECT). Most of the patients had normal mean hemispheric cerebral blood flow (mCBF), comparable to that of age-matched healthy children. However, they had abnormal rCBF distribution and disturbed reactivity to acetazolamide in the territory of the internal carotid artery, especially in the frontal lobe. Surgical revascularization for the anterior circulation, which consisted of STA-MCA anastomosis and indirect synangiosis, dramatically improved these cerebral hemodynamics in the anterior circulation, including the frontal lobe, and reactivity to acetazolamide in the whole brain. These results suggest that surgical revascularization for the anterior circulation should be carried out in order to improve cerebral hemodynamics as widely as possible, especially in the frontal lobe, and may improve cerebral perfusion reserve in the posterior circulation.

Acetazolamide↗
PubMed1995

A3-A3 side-to-side anastomosis in the anterior communicating artery aneurysm surgery: report of four cases.

BACKGROUND: Giant or large aneurysms prevent direct clipping without compromise of the parent vessels, and any countermeasures should be attempted. METHODS: We describe an A3-A3 side-to-side anastomosis as a method of revascularization of the pericallosal artery in surgery of an aneurysm of the anterior communicating artery (ACoA) in four patients. RESULTS: In two patients with the pericallosal artery narrowed or occluded by the clipping or trapping procedure, and in two other patients with giant aneurysms clipped with prolonged duration of temporary occlusion of the parent vessels, no serious neurologic changes were observed after surgery. CONCLUSIONS: We believe that an A3-A3 side-to-side anastomosis is effective in preventing ischemic complications in the territory of the pericallosal artery.

Aged↗
PubMed1995

Postsurgical observations of mean hemispheric cerebral blood flow with patients receiving high-flow EC-IC bypass using a radial artery graft (preliminary report, one-year observation of 10 hemispheres).

BACKGROUND: When we encounter an inaccessible internal carotid artery lesion, we sacrifice the inaccessible internal carotid artery and, at the same time, establish a high-flow extracranial-to-intracranial arterial bypass (EC-IC bypass). Questions and concerns remain, however, about the dynamics of the patient's cerebral blood flow postoperatively. METHOD: Ten hemispheres from 9 patients had received radial artery grafting as an EC-IC bypass with the simultaneous obstruction of the internal carotid artery. Their mean hemispheric cerebral blood flow (mCBF) was measured longitudinally during 1 year after surgery by single photon emission computed tomography (SPECT) and a 133Xenon-inhalation method. RESULTS: The serial mCBF values of the five hemispheres with giant aneurysm or paracavernous meningioma were attenuated during the postoperative 3-month period and then returned to the normal range. In only one case did the postoperative reduction of mCBF fail to return to normal; in addition there was a memory disturbance that had developed and progressed. Five hemispheres with the ICA stenosis did not present reduction in mCBF. In three out of five hemispheres, transient elevation of mCBF at 1 month after surgery was observed.

Aged↗
PubMed1995

Cerebral haemodynamics and long-term prognosis after extracranial-intracranial bypass surgery.

The effectiveness of extracranial-intracranial arterial (EC-IC) bypass surgery for haemodynamic stroke remains controversial. In this study correlation of presurgical and postsurgical cerebral haemodynamics with long term prognosis was evaluated. Twenty eight patients (25 men, three women: mean age 61.4 (SD 8.2) years) with reduced cerebrovascular reserve due to steno-occlusive cerebral vascular disease formed the study group. Measurement of mean hemispheric cerebral blood flow (mCBF) and the cerebral vasodilatory capacity (% mCVR) with an intravenous acetazolamide injection were performed by a xenon-133 inhalation method and SPECT. Patients were treated with EC-IC bypass surgery and measurements of mCBF and % mCVR were made again about one month after surgery. The patients were then observed for a long period (range 27-115 months). During the observation period, four patients experienced subsequent ischaemic strokes. The presurgical and the postsurgical resting mCBF for the affected hemisphere were significantly reduced in the patients with strokes during follow up compared with the values in patients without strokes during follow up (P < 0.03 and 0.01 respectively). The % mCVR of the affected hemisphere was significantly raised after surgery in all patients except one (P < 0.01). The postsurgical change in resting mCBF was not unidirectional. In conclusion, resting mCBF was unchanged and % mCVR was improved after EC-IC bypass surgery in patients with reduced cerebrovascular reserve. The group of patients with a reduced presurgical and postsurgical resting mCBF continue to be a high risk group for subsequent ischaemic stroke seen after EC-IC bypass surgery.

Aged↗