Biomedical subjects

T Yasui

Publications and source records attributed to T Yasui.

At least 109 records · Page 6Linked to original sources

PubMed1999

Vectorcardiographic evaluation of myocardial infarct size: comparisons with thallium myocardial scintigraphy.

OBJECTIVE: To determine the usefulness of vectorcardiography (VCG) in assessing myocardial infarct size. METHODS: The correlation of spatial and scalar parameters of VCG with the percent defect volume (%DV) of thallium myocardial single photon emission computed tomography (SPECT) was investigated in 63 patients with first-onset myocardial infarction (MI). VCG parameters included: (1) spatial parameters: magnitude, azimuth and elevation of the maximal vector, vectors at 20 ms and 30 ms, and (2) scalar parameters: amplitudes of 20 ms and 30 ms vectors at X, Y, and Z scalar leads abbreviated as X20, Y20, Z20, X30, Y30 and Z30, respectively. RESULTS: For anteroseptal MI, the azimuth of 30 ms vector and Z20 showed a significant correlation with %DV (r = 0.572, P < 0.05 and r = 0.832, P < 0.001) while in anteroseptal MI with involvement of lateral wall, the azimuth of 30 ms vector and X30 were correlated with %DV significantly (r = 0.775, and r = 0.780, P < 0.01). For inferior and inferoposterior MI, the elevation of 30 ms vector and Y30 were correlated well with %DV (r = 0.871, P < 0.01, r = 0.928, P < 0.001 for inferior MI and r = 0.678, P < 0.01, r = 0.760, P < 0.001 for inferoposterior MI). CONCLUSION: VCG parameters, especially scalar parameters, can be used to evaluate myocardial infarct size easily and non-invasively with remarkable accuracy.

Aged↗

PubMed1998

Transcriptional regulation of osteopontin gene in vivo by PEBP2alphaA/CBFA1 and ETS1 in the skeletal tissues.

Osteopontin (Opn) and polyoma enhancer-binding protein (PEBP) 2alphaA/core binding factor (CBFA) 1 have been suggested to play important roles in ossification. The overlapping localization of opn and PEBP2alphaA/CBFA1 mRNA, and the marked decrease of opn mRNA expression in PEBP2alphaA knockout mice, indicated that the transcription of opn gene was controlled by PEBP2alphaA. In the present study, we determined the direct regulation of PEBP2alphaA on the opn promoter activity. Opn promoter activity was markedly enhanced by PEBP2alphaA and ETS1 in a synergistic manner. The synergistic effect was diminished when either the PEBP2alphaA or ETS1 binding site was mutated, or the spatial arrangement of these sites was mutated by a 4-nt insertion. The distance between these sites was important for transactivation but not protein-DNA binding. The direct interaction between PEBP2alphaA and ETS1 was depended on protein-DNA binding. These results suggested that the specific spatial arrangement of both sites and direct interaction between PEBP2alphaA and ETS1, were essential for promoter function. Furthermore, endogenous opn mRNA was decreased with the introduction of dominant negative PEBP2alphaA to MC3T3/E1 cells expressing endogenous PEBP2alphaA, ETS1 and opn. These findings suggest that PEBP2alphaA and ETS1 cooperate in vivo to regulate expression of the opn gene in the skeletal tissue. Cell type-specific regulation of Opn gene expression will also be discussed.

3T3 Cells↗

PubMed1998

Serial MR observation of cortical laminar necrosis caused by brain infarction.

To examine the chronological changes characteristic of cortical laminar necrosis caused by brain infarction, 16 patients were repeatedly examined using T1-, T2-weighted spin-echo, T2*-weighted gradient echo, fluid attenuated inversion recovery (FLAIR) images, and contrast enhanced T1-weighted images at 1.0 or 1.5 T. High intensity cortical lesions were visible on the T1-weighted images from 2 weeks after ictus and became prominent at 1 to 3 months, then became less apparent, but occasionally remained at high intensity for 2 years. High intensity cortical lesions on FLAIR images became prominent from 1 month, and then became less prominent from 1 year, but occasionally remained at high intensity for 2 years. Subcortical lesions did not display high intensity on T1-weighted images at any stage. On FLAIR images, subcortical lesions initially showed slightly high intensity and then low intensity from 6 months due to encephalomalacia. Cortical lesions showed prominent contrast enhancement from 2 weeks to 3 months, but subcortical lesions were prominent from 2 weeks only up to 1 month. T2*-weighted images disclosed haemosiderin in 3 of 7 patients, but there was no correlation with cortical short T1 lesions. Cortical laminar necrosis showed characteristic chronological signal changes on T1-weighted images and FLAIR images. Cortical short T1 lesions were found not to be caused by haemorrhagic infarction.

Adult↗

PubMed1998

Alendronate inhibits osteopontin expression enhanced by parathyroid hormone-related peptide (PTHrP) in the rat kidney.

It has been reported that osteopontin (OPN) plays an important role during urolithiasis as well as bone formation. Generation of stones in the urinary tract may be associated with osteoporosis and bisphosphonates are potent inhibitors of bone resorption, being used with effect in the management of bone disease. We therefore investigated the relationship between alendronate, a bisphosphonate derivative, and OPN expression in the kidney. Alendronate was administered to rats made hypercalcemic by treatment with parathyroid hormone-related peptide (PTHrP). The renal expression of OPN was then evaluated at both protein and mRNA levels. OPN expression was enhanced in the distal tubular cells of hypercalcemic rats and was decreased by alendronate. The observed inhibition of OPN expression suggests an ability of alendronate and other bisphosphonates to act as inhibitors of stone formation in the urinary tract.

Alendronate↗

PubMed1998

Effects of methyl ethyl ketone, acetone, or toluene coadministration on 2,5-hexanedione concentration in the sciatic nerve, serum, and urine of rats.

OBJECTIVE: To clarify changes in the serum, nerve, and urinary levels of 2,5-hexanedione (2,5-HD) in rats on coadministration with methyl ethyl ketone (MEK), acetone (AC), and toluene (TO). METHOD: 2,5-HD alone or combined with MEK, AC, and TO was injected subcutaneously into a total of 306 male Wistar rats. The rats were divided as follows into 7 groups: (1) 2.6 mmol/kg 2,5-HD alone (HD) and (2) 2.6 mmol/ kg 2,5-HD combined with 2.6 mmol/kg MEK (HD + MEK), (3) with 2.6 mmol/kg AC (HD + AC), (4) with 2.6 mmol/kg TO (HD + TO), (5) with 13.0 mmol/kg MEK (HD + 5MEK), (6) with 13.0 mmol/kg AC (HD + 5AC), and (7) with 13.0 mmol/kg TO (HD + 5TO). 2,5-HD concentrations in the serum, sciatic nerve, and urine of rats were determined within 16 h of the injections and pharmacokinetic parameters were estimated. RESULTS: It was observed that (1) the 2,5-HD concentration and AUC value (area under concentration versus time curve) determined in the serum and nerve increased significantly in the cotreated groups as compared with the HD group; (2) the effect MEK had in elevating the 2,5-HD concentration and AUC in the serum and nerve was stronger than that of AC, and the effect AC had was stronger than that of TO; (3) a. dose increase from 2.6 to 13.0 mmol/kg for MEK and AC induced further increases in the 2,5-HD concentration and AUC determined in the serum and nerve; (4) elimination constants recorded for 2,5-HD (Ke) from the serum and nerve decreased in all the cotreated groups, and the degree of the decrease correlated inversely with the elevation in 2,5-HD concentration and AUC in the serum and nerve; and (5) urinary 2,5-HD concentrations measured in the 13.0-mmol/kg cotreated groups increased in parallel with the elevation in serum 2,5-HD concentrations. CONCLUSION: Coadministration of 2,5-HD with MEK, AC, or TO can increase the concentration and AUC of 2,5-HD in serum and the sciatic nerve, and these increases can be further enhanced by an increase in the concomitant doses of MEK and AC.

Acetone↗

PubMed1998

Intracranial aneurysms in identical twins.

BACKGROUND: Though familial intracranial aneurysms are well documented, only a few cases of intracranial aneurysms in identical twins have been reported. CASE REPORT: Our patient, a 46-year-old woman, presented with a subarachnoid hemorrhage (SAH) due to a ruptured aneurysm. At the age of 36, her identical twin sister had also suffered SAH from a ruptured aneurysm. Both twins were treated successfully. CONCLUSION: The likelihood of the occurrence of an aneurysm may be higher for a twin whose identical twin has developed an aneurysm than for the general population. Therefore, it is reasonable to perform certain screening procedures for aneurysms on an asymptomatic twin when the other presents with SAH due to a ruptured aneurysm.

Diseases in Twins↗

PubMed1998

Relationship between 2,5-hexanedione concentrations in nerve, serum, and urine alone or under co-treatment with different doses of methyl ethyl ketone, acetone, and toluene.

To ascertain the relationship among 2,5-hexanedione (2,5-HD) concentrations in nerve, serum and urine, rats were injected subcutaneously with 2.6 mmol/kg 2,5-HD alone, or together with 2.6 or 13.0 mmol/kg of methyl ethyl ketone, acetone and toluene. 2,5-HD concentrations in sciatic nerve (NC), serum (SC) and urine (UC) were determined, and the linear regression between each two of NC, SC, and UC were calculated. There was good correlation between NC and SC, SC and UC in the 2,5-HD alone group, and good correlation between NC and SC in the co-treated groups. Co-treatment solvent had little effect on the relationship between SC and NC. 13.0 mmol/kg co-treated solvent tended to decrease the regression coefficients compared with 2.6 mmol/kg co-treated solvent. These results show that SC can be used in estimating NC in the 2,5-HD alone or co-treated groups, and UC can be used in estimating SC in the 2,5-HD alone group.

Acetone↗

PubMed1998

Body composition analysis of cachectic rabbits by total body electrical conductivity.

A simple formula (1.536 x TOBEC + 475.146 = LBM, where TOBEC is total body electrical conductivity and LBM is lean body mass) to estimate LBM in grams was developed on the basis of the total body fat data obtained by ether extraction and TOBEC in normal rabbits. The formula was also applicable to rabbits with cachexia induced by inoculation of VX2 carcinoma or by starvation. We were able to assess the losses of body fat in the rabbits with cachexia at 10-day intervals by using TOBEC.

Animals↗

PubMed1998

Bilateral dissecting aneurysms of the vertebral arteries resulting in subarachnoid hemorrhage: case report.

OBJECTIVE AND IMPORTANCE: We present the case of a patient with bilateral dissecting aneurysms of the vertebral arteries resulting in subarachnoid hemorrhage. CLINICAL PRESENTATION: A 44-year-old man suffered a sudden onset of severe occipital headache and nausea and then dysphasia caused by subarachnoid hemorrhage. A computed tomographic scan demonstrated right side dominant subarachnoid hemorrhage mainly in the posterior fossa. Angiography revealed bilateral, vertebral dissecting aneurysms. The right aneurysm was larger and had a bleb-like protrusion, which strongly suggested a causative lesion of the subarachnoid hemorrhage. Six months later, the patient was referred to our hospital for further evaluation and treatment. INTERVENTION: The ruptured right aneurysm was trapped surgically through a lateral suboccipital approach. The patient's postoperative course was unremarkable, and he was discharged on the 14th day after surgery. However, postoperative angiography demonstrated slight enlargement of the left nonruptured aneurysm. Four months after surgery, the patient developed brain stem ischemic symptoms. The angiography conducted at that time showed further enlargement of the left aneurysm. Five months after surgery, fatal rupture of the left aneurysm occurred. CONCLUSION: These results indicate that sacrifice of the unilateral vertebral artery may result in an enlargement of the contralateral nonruptured aneurysm and may thus be dangerous in the case of a patient with bilateral dissecting aneurysms.

Adult↗

PubMed1998

Moyamoya disease and pregnancy: case report and review of the literature.

OBJECTIVE AND IMPORTANCE: Many female patients with moyamoya disease are of childbearing years, including those who were diagnosed before entering their childbearing years. However, there have been no extensive reviews of the management of pregnancy and delivery in association with moyamoya disease. The purpose of this report is to describe the case of a patient with moyamoya disease complicated by pregnancy and to review the literature on other such cases. CLINICAL PRESENTATION AND INTERVENTION: We report a 23-year-old primipara with moyamoya disease who delivered uneventfully by cesarean section under spinal anesthesia at 38 weeks of gestation. In the literature, 30 cases were reported of patients who had been diagnosed with moyamoya disease before pregnancy and delivery, and 23 patients who were symptomatic and were diagnosed for the first time with moyamoya disease in association with pregnancy. CONCLUSION: There is no evidence that pregnancy increases the risk of cerebrovascular accident or that bypass surgery decreases its risk. Poor prognosis of the patient or the newborn is mostly caused by cerebral hemorrhage and not by cerebral ischemia. It is important to control blood pressure and especially to avoid toxemia during pregnancy. Either cesarean section or vaginal delivery can be accomplished safely. Any anesthetic method can be used, provided special attention is given to avoiding hypocapnia, hypotension, and hypertension. Oral contraceptives should be avoided.

Adult↗

PubMed1998

Scrotal lymphangioma.

We report a case of scrotal lymphangioma. A 6-year-old boy was referred to our hospital due to a right scrotal mass with tenderness. On physical examination the mass was discriminated from the testis and showed transillumination. Total surgical excision of the mass was performed. The lesion was multicystic, and adherent to the skin. Pathological examination revealed lymphangioma. Total surgical excision is considered the treatment of choice for this disease.

Child↗

PubMed1998

Vectorcardiographic evaluation of myocardial infarct size: departure parameters are superior to conventional spatial parameters.

To determine whether the departure parameters derived from a "departure loop" of a vectorcardiogram are more accurate than conventional spatial parameters in evaluating myocardial infarct size, 74 patients with first-onset myocardial infarction (MI) were studied. The correlation between the departure parameters (amplitudes in scalar leads of the departure loop) and the percent defect volume of thallium myocardial scintigrams (%DV) was compared with that of the spatial parameters (magnitude, azimuth, and elevation of the original QRS loop). In anteroseptal MI, the amplitude of a 20-msec vector in the z-axis and the azimuth of a 30-msec vector (H30) were significantly correlated with %DV (r=0.783, p<0.001 and r=0.572, p<0.05). In anteroseptal MI with involvement of the lateral wall, the amplitude of a 30-msec vector in the x-axis and H30 showed significant correlation with %DV (r=0.802, p<0.001 and r=0.772, p<0.01). In inferior and inferoposterior MI, the amplitude of a 30-msec vector in the y-axis and the elevation of a 30-msec vector were significantly correlated with %DV (r=0.920, 0.891, p<0.001 and r=0.871, 0.678, p<0.01, respectively). In conclusion, the departure parameters are more accurate than the spatial parameters for evaluation of myocardial infarct size.

Aged↗

PubMed1998

Magnetic resonance imaging features of unusually dilated Virchow-Robin spaces--two case reports.

Two patients presented with unusually dilated Virchow-Robin spaces appearing as cystic lesions of varying size with signal intensity identical to the cerebrospinal fluid on all magnetic resonance pulse sequences. However, fluid-attenuated inversion-recovery (FLAIR) images disclosed small, high intensity foci adjacent to these cystic lesions in one patient. These high intensity foci on FLAIR images may represent chronic ischemic change, which produces the gradual dilation of the Virchow-Robin spaces.

Adult↗

PubMed1998

Embolic stroke in the territory of a cerebellar arteriovenous malformation--case report.

A 63-year-old male presented with an embolic stroke in the right medial inferior cerebellum. Angiography at 2 and 8 months after the stroke revealed arteriovenous shunts from the vermian branch of the right posterior inferior cerebellar artery of the right inferior vermian vein. The shunts mimicked the arteriovenous shunts of post-recanalization in acute ischemic stroke, but were finally diagnosed as a pre-existing congenital arteriovenous malformation based on their persistence. Arteriovenous shunts that persists more than 2 weeks after ictus should be differentiated from the post-recanalization arteriovenous shunts of ischemic stroke, as the different etiology may affect the ultimate prognosis and course of treatment.

Cerebellum↗

PubMed1998

Cerebellar mutism after basilar artery occlusion--case report.

A 30-year-old female became comatose due to embolic occlusion of the basilar artery, caused by surgical injury to the origin of the vertebral artery during removal of a neurinoma in the upper thoracic paravertebral region. The basilar artery occlusion was treated by local fibrinolysis through a microcatheter. Two weeks later she recovered her consciousness but suffered mutism. Her speech disturbance was characterized by severe ataxic dysarthria known as "cerebellar mutism" but without cranial nerve paresis. The mutism gradually improved during the following 3 months. This is case of cerebellar mutism was apparently due to ischemic stroke. Disturbance by hypoperfusion of the cerebellum and brain stem may have been involved in the pathogenesis of cerebellar mutism.

Adult↗

PubMed1998

Rupture mechanism of a thrombosed slow-growing giant aneurysm of the vertebral artery--case report.

A 76-year-old male developed left hemiparesis in July 1991. The diagnosis was thrombosed giant vertebral artery aneurysm. He showed progressive symptoms and signs of brainstem compression, but refused surgery and was followed up without treatment. He died of rupture of the aneurysm and underwent autopsy in March 1995. Histological examination of the aneurysm revealed fresh clot in the aneurysmal lumen, old thrombus surrounding the aneurysmal lumen, and more recent hemorrhage between the old thrombus and the inner aneurysmal wall. The most important histological feature was the many clefts containing fresh blood clots in the old thrombus near the wall of the distal neck. These clefts were not lined with endothelial cells, and seemed to connect the lumen of the parent artery with the most peripheral fresh hemorrhage. However, the diameter of each of these clefts is apparently not large enough to transmit the blood pressure of the parent artery. Simple dissection of the aneurysmal wall by blood flow in the lumen through many clefts in the old thrombus of the distal neck may be involved in the growth and rupture of thrombosed giant aneurysms of the vertebral artery.

Aged↗

PubMed1998

Middle cerebral artery variations: duplicated and accessory arteries.

PURPOSE: Our goal was to analyze the anatomic similarity between the duplicated middle cerebral artery (MCA) and the accessory MCA and their relationship to the early branches of the MCA. METHODS: We reviewed stereoscopic angiograms of duplicated MCAs in four patients and accessory MCAs in four patients with reference to the origin, size, and cortical supply of these anomalous vessels, along with the presence of perforating arteries and the recurrent artery of Heubner (RAH). RESULTS: The duplicated MCAs supplied the cortical territory of the temporopolar and the anterior temporal and/or middle temporal arteries. The accessory MCAs supplied the cortical territory of the orbitofrontal and/or prefrontal arteries. The duplicated MCAs had perforating arteries in three of four cases and coexisted with the RAH in three of four cases, whereas the main MCA had perforating arteries in all four cases. The accessory MCA had perforating arteries in all four cases and coexisted with the RAH in three of four cases, whereas the main MCA had perforating arteries in one of four cases. CONCLUSION: A consistent cortical supply by the duplicated MCA and the accessory MCA to the anterior temporal lobe and the anterior frontal lobe, respectively, and its similarity to the cortical supply by the early branches of the MCA suggest that development of duplicated and/or accessory MCAs is an anomalously early ramification of the early branches of the MCA.

Adult↗

PubMed1998

[Indications for external ventricular drainage after clipping of ruptured aneurysms in the acute stage].

The indication for external ventricular drainage after clipping of ruptured aneurysms in the acute stage is evaluated. Since 1990, 234 patients who presented with subarachnoid hemorrhage (SAH) and underwent aneurysmal clipping in the acute stage were evaluated retrospectively. Patients with ventricular dilatation had intraoperative placement of a ventriculostomy to obtain intraoperative brain relaxation, but the ventricular catheter was removed at the end of the surgery. All these patients were managed postoperatively in a similar fashion with no ventricular drainage, avoidance of dehydration complemented by a course of sodium ozagrel and nicardipine or fasudil hydrochloride. Acute hydrocephalus was defined as clinically and radiographically demonstrated ventricular dilatation that developed within 2 weeks of the onset of SAH and that required ventricular drainage. Three surgical approaches were employed; pterional approach (PA) for the aneurysms of the anterior circulation and upper basilar artery in 207 patients, interhemispheric approach (IHA) for the aneurysms of the pericallosal artery in 11 patients and lateral suboccipital approach (LSA) for the aneurysms of the vertebral arteries in 16 patients. No significant differences were found among these three approach groups in Fisher CT classification and the Hunt & Kosnik gradings. Four patients developed acute hydrocephalus within two weeks of surgery: three patients were operated on via LSA and one through IHA. Compared to the IHA or LSA, PA was superior for reestablishing cerebrospinal fluid circulation, because it is possible to remove more subarachnoid clot in the basal cisterns than to do so in the other two approaches. Opening of the lamina terminalis and the Liliequist membrane are also possible using PA. In conclusion, PA can prevent development of acute hydrocephalus, whereas postoperative ventricular drainage may be necessary in patients operated upon via IHA or LSA.

Acute Disease↗