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Biomedical subjects

N Shimazu

Publications and source records attributed to N Shimazu.

At least 19 recordsLinked to original sources
PubMed2001

Doxazosin, an alpha1-adrenergic antihypertensive agent, decreases serum oxidized LDL.

Oxidized low-density lipoprotein (ox-LDL) is well known to play an important role in atherogenesis through the recruitment of monocytes into vessel walls and the deposition of cholesterol ester in the macrophages, which leads to the formation of lipid-rich plaque. It was assumed that only trace amounts of ox-LDL were present in plasma because the half-life of ox-LDL was only a few minutes. Recently, through the use of a monoclonal antibody against ox-LDL, a quantitative method to measure serum ox-LDL concentration has been developed. Metabolites of doxazosin, an alpha1-adrenergic antihypertensive agent, have been reported to inhibit oxidation of LDL in vitro. In this study, we investigated the in vivo effect of doxazosin on LDL oxidation using this new method to measure serum ox-LDL concentration. After the administration of doxazosin for 1 to 2 months, serum concentration of ox-LDL decreased significantly (P < .05). Although the reduction of ox-LDL concentration does not strictly indicate doxazosin's antiatherosclerotic effect, it may constitute one of doxazosin's additional weapons beside lowering blood pressure and serum lipid values in the prevention of atherosclerosis.

Adrenergic alpha-Antagonists↗
PubMed1999

[Chylomicron].

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Chylomicrons↗
PubMed1998

Internal thoracic-carotid bypass surgery for Takayasu's arteritis.

BACKGROUND: Various carotid reconstructions have been used in Takayasu's arteritis (TA) to relieve brain ischemic insult. The indications and guidelines for surgical management, however, have remained poorly defined. The authors present a new reconstructive procedure using the sequential internal thoracic artery (ITA) as the donor for bypass surgery to supplement the cerebral blood flow. CASE DESCRIPTION: A 38-year-old woman presented with three episodes of syncope. The patient was admitted to our hospital and was diagnosed with TA. Before the operation, the patient was designated to undergo aortocarotid bypass using saphenous veins. However, a dilated ascending aorta with an extremely thin wall made it impossible. Finally, we decided to use the ITA as the donor for bypass surgery. This patient is now free of cerebral ischemic insult 8 months after the operation. CONCLUSION: Although the procedure is still at a preliminary stage, a successful case is briefly described.

Adult↗
PubMed1998

[Pituitary enlargement in spontaneous intracranial hypotension on MRI].

PURPOSE: To examine whether the pituitary gland enlarges in patients with spontaneous intracranial hypotension (SIH). MATERIALS AND METHODS: All six patients were women ranging in age from 17 to 51 years. They developed severe headache that was completely relieved by lying flat, and MR imaging showed diffuse enhancement of the pachymeninx. They were clinically diagnosed with SIH. The height of the pituitary gland was measured on midsagittal MR image. RESULTS: Pituitary heights ranged from 8 to 11 mm. The measurements were greater than the size of the normal pituitary gland in women described age-matched in the previous report. In one case, follow-up MR images showed that the size of the pituitary gland was decreased from 11 to 5 mm in height. CONCLUSION: The pituitary gland was enlarged in all six patients with SIH on MR images. SIH may cause enlarged pituitary gland.

Adolescent↗
PubMed1997

[Active MR tracking system at 0.2T MR, a preliminary report: real time position tracking on interventional MR].

An active MR tracking system was installed in a 0.2 T open-type MRI. Interventional devices with a receive-only microcoil at their tips were newly developed for tracking at 0.2T. The low signal-to-noise ratio at 0.2T required the microcoils to have a diameter of about 2 mm and 20 turns for stable tracking. Simulation of MR-guided biopsy using biplane images with tracking in the gelatin phantom was performed. MR tracking in the aorta and IVC of a dog by a catheter with a microcoil at its tip was successful.

Animals↗
PubMed1996

CETP is a determinant of serum LDL-cholesterol but not HDL-cholesterol in healthy Japanese.

Cholesteryl ester transfer protein (CETP) is one of the factors that regulate plasma levels of HDL-cholesterol. To identify the factors that may regulate CETP activity, and to determine to what extent CETP is correlated with physiologic concentrations of lipoprotein, we performed an epidemiologic study in 586 healthy volunteers (317 males and 269 females mean age 52.2 +/- 10.9 years). CETP activity in these subjects was 192.96 +/- 48.73 (mean +/- S.D.) nmol/ml/h and distributed to a wide range (60-450 nmol/ml/h). Using multiple regression analysis, we found significant positive correlations between CETP activity and LDL-cholesterol (P < 0.03), apolipoprotein (apo) E (P < 0.005) and LCAT activity (P < 0.001). CETP activities showed significant negative correlation with apo A-I (P < 0.03). However, CETP activity showed no significant correlation either with HDL cholesterol or with apo B. One-way layout analysis of variance showed that alcohol drinking and cigarette smoking significantly reduced CETP activity, but there was no significant association between CETP activity and body mass index. Although CETP activities were significantly higher in females than in males (P < 0.001), multiple regression analysis showed no correlation between CETP activity and age in either the males or the females. Our results suggest that CETP activity regulates the concentration of apo A-I and LDL-cholesterol, and that such activity may be influenced by gender, alcohol consumption and cigarette smoking.

Adult↗
PubMed1995

Role of acyl coenzyme A cholesterol acyltransferase in intrahepatic processing of apo B-lipoprotein in suncus.

We have previously shown that fatty liver was easily induced in suncus by starvation and that the plasma level of apolipoprotein B (apoB) was very low. We also previously reported that a defect in the assembling process of apo B-containing lipoprotein (very low density lipoprotein, VLDL) may be one of the reasons for the low level of plasma apo B and for induction of fatty liver by starvation in suncus. We also found that hepatic acyl coenzyme A cholesterol acyltransferase (ACAT) activity is very low in the animals, resulting in decreased cholesteryl ester contents in the liver. A deficiency of cholesteryl ester in suncus liver may be one of the reasons for the defect in the assembling process of VLDL. In this study, we investigated the effect of cholesterol-feeding, which induces an increase in triglyceride and cholesteryl ester of the liver as a consequence of the induction of both intestinal and hepatic ACAT activities, on the secretion of VLDL. Although the basal ACAT activity of intestinal mucosa was high, cholesterol-feeding did not induce either an increase in plasma lipid or an increase in intestinal ACAT activities in suncus. The hepatic secretion rate of VLDL was estimated by treatment with Triton WR1339, which is well known to inhibit the catabolism of VLDL. Cholesterol-feeding caused a slight increase in hepatic triglyceride and cholesteryl ester but no increase either in the secretion rate of VLDL or in hepatic ACAT activity.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1995

Importance of impairment of the airway epithelium for ozone-induced airway hyperresponsiveness in guinea pigs.

We examined the relationship between ozone (O3)-induced airway hyperresponsiveness (AHR) and inflammation in guinea pigs. Inhalation of methacholine (MCh) was adopted in the time course study of AHR that was assessed by measuring pulmonary inflation pressure after O3 exposure (3 ppm, for 2 hr) because the degree of AHR detected by inhalation of MCh was greater than that detected by i.v. administration. AHR was detected up to 5 hr after O3 exposure and was not observed at 24 and 48 hr. In the bronchoalveolar lavage (BAL) study, the numbers of neutrophils, eosinophils, lymphocytes and macrophages in BAL fluid (BALF) reached maximum at 24 hr or later. On the other hand, the number of airway epithelial cells in the BALF significantly increased at 2 and 5 hr. In the histological study, disorder and impairment of the airway epithelium in the trachea and lung were observed at 2 and 5 hr. Changes in the airway epithelium were recovered at 48 hr, although an increase in leukocytes was observed in the lung. These results indicate that O3-induced AHR in guinea pigs is most probably associated with impairment of the epithelium rather than with infiltration of inflammatory cells in the airway.

Administration, Inhalation↗
PubMed1995

[Chylomicron].

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Chylomicrons↗
PubMed1994

Peripheral anterior inferior cerebellar artery aneurysms.

Two cases of peripheral anterior inferior cerebellar artery (AICA) aneurysms are reported. The first case was a 60-year-old man who showed frequent attacks of subarachnoid hemorrhage (SAH) and hearing disturbance. His aneurysm was obliterated by trapping the AICA and his neurologic status was unchanged compared with preoperatively. The second case had SAH without cranial nerve involvement; this aneurysm was obliterated by neck clipping. He was discharged without neurologic deficit. Peripheral AICA aneurysm has already been reported in 48 cases including arteriovenous malformation-associated cases. This aneurysm may show cranial nerve involvement (seventh and eighth) without SAH as in the case of internal carotid-posterior communicating artery aneurysms. We review the clinical signs of these cases and discuss them from the point of view of anatomic variations of the AICA and internal auditory artery.

Aged↗
PubMed1993

[Thalamic infarction in young adult caused by embolism from an unruptured aneurysm of the posterior cerebral artery--a case report].

A 21-year-old man presented with sudden weakness and dysesthesia of his right limbs. Computerized tomography (CT) scan showed a low density area in the posterolateral part of the left thalamus. Right vertebral angiography revealed a small aneurysm at the P2 segment of the posterior cerebral artery. Magnetic resonance imaging (MRI) demonstrated intra-aneurysmal clot and signal void in the residual lumen. There were no other lesion and no predisposing risk factors that produced cerebral ischemia. It was thought that the aneurysm was the source of emboli resulting in thalamic infarction. The patient underwent a left subtemporal craniotomy, and the aneurysm was clipped. Following surgery, there has been no recurrence of ischemic attacks. The diagnosis and the therapy were discussed, with reference to the literature.

Adult↗
PubMed1991

Systemic histopathology of rats with CCl4-induced hepatic cirrhosis.

Systemic histopathological examinations were carried out on rats with CCl4-induced hepatic cirrhosis. Moderate congestion in the spleen, prominent oedema in the focal acinar cell degeneration in the pancreas, marked haemorrhage and phagocytosis of haemosiderin by macrophages in the pancreaticoduodenal lymph node, appearance of monocytes bearing haemosiderin-like granules in the pulmonary arteries and cardiac right atrium, and focal segmental glomerulosclerosis were consistently observed in rats with hepatic cirrhosis. In addition, a marked increase in number of target cells and the appearance of a small number of monocytes bearing haemosiderin-like granules were also commonly found in the peripheral blood smears of these animals. These findings are considered to be important in the use of the CCl4-induced model of hepatic cirrhosis in the rat.

Animals↗
PubMed1991

Brain metastasis of thyroid papillary carcinoma--case report.

A rare case of brain metastasis of thyroid papillary carcinoma is reported. The cerebral metastasis was surgically treated without irradiation despite the presence of a spinal metastasis. No recurrence was demonstrated by computed tomography 1 year postoperatively. We suggest that surgery is indicated for a brain metastasis of thyroid papillary carcinoma even if other metastatic lesions are present.

Adenocarcinoma, Papillary↗
PubMed1986

[Tuberous sclerosis with intraventricular tumor: report of 2 cases].

It is well known that intraventricular tumors are occasionally seen in patients with tuberous sclerosis. We have experienced two cases of tuberous sclerosis with intraventricular tumor. Case 1: an 8-year-old girl was admitted to our clinic because of headache and vomiting of one month's duration. She had adenoma sebaceum, mental retardation and seizures clinically, and a large tumor was found in the right lateral ventricle by pneumoventriculography. Partial removal of the tumor was performed by the right frontal transcortical approach, but she later died of pneumonia. Necropsy revealed hamartomatous disease characterized by multiple focal tumor-like malformations in various organs including the brain, kidneys, heart, lungs and liver. The histological diagnosis of the intraventricular tumor was subependymal giant cell astrocytoma. Case 2: a 6-year-old boy was admitted to our clinic because of headache of one year's duration. He had also suffered from seizures since 6 months of age. Adenoma sebaceum was noted in the cheeks. CT revealed a medium sized tumor at the right foramen of Monro and the moderately dilated right lateral ventricle and several calcified deposits in the lateral ventricle wall. The tumor was subtotally removed by the right frontal transcortical approach. The pathological examination showed subependymal giant cell astrocytoma. Now 6 years after the operation he is enjoying a normal school life. In our cases, intraventricular tumors associated with tuberous sclerosis were of a typically benign histological appearance, that is subependymal giant cell astrocytoma.(ABSTRACT TRUNCATED AT 250 WORDS)

Astrocytoma↗
PubMed1986

[Effect of calcium antagonist (diltiazem) on symptomatic cerebral vasospasm--with special reference to CT classification].

CT is important for detecting subarachnoid clots and intracerebral or intraventricular hemorrhage. The presence of subarachnoid clots surrounding the cerebral arteries may be one of the causes of cerebral vasospasm. It is agreed that there is a correspondence between the site of subarachnoid clots and the location of cerebral vasospasm. The authors have already reported that the appearance and severity of symptomatic cerebral vasospasm were not affected by calcium antagonists (Diltiazem), but the prognosis improved significantly for 105 patients (especially Hunt-Hess grade II and III) at the 3-month follow-up examination. In this study, the above 105 patients, each with a ruptured supratentorial aneurysm, were classified preoperatively according to Fisher's CT grading system and the effect of Diltiazem was re-examined. Patients in Hunt-Hess grade V were excluded and the duration of treatment with Diltiazem was 2 weeks following the operation. 105 cases (Diltiazem) were compared as a control group with 100 cases who were operated on before the administration of Diltiazem. The frequency of occurrence of symptomatic cerebral vasospasm tended to decline in patients with a CT grade of 2 or 3, and the prognosis improved significantly for 105 patients including 32 cases with symptomatic cerebral vasospasm. The preliminary results here indicate that Diltiazem might be especially effective for patients of Hunt-Hess grade II and III with CT grades of 2 and 3.

Adult↗
PubMedDate not supplied

Well-differentiated hepatocellular carcinoma: findings of US, CT, and MR imaging.

BACKGROUND: To elucidate the imaging characteristics of well-differentiated hepatocellular carcinomas (HCCs) on ultrasonography (US), computed tomography (CT), and magnetic resonance (MR) imaging. METHODS: Ultrasonograms, CTs, and MR images of 18 histopathologically proven well-differentiated HCCs in 15 patients were reviewed. The findings of these images were correlated with histopathologic findings. RESULTS: On US, seven tumors were depicted as a hyperechoic area and eight as a hypoechoic area. Three tumors were not visualized. On precontrast CT, four tumors were depicted as a low-density area, but 14 were not visualized. On conventional contrast-enhanced CT, 12 tumors were depicted as a low-density area but six were not visualized. On T1-weighted MR images, 10 tumors had high signal intensity and two had low signal intensity. Six tumors were not visualized. On T2-weighted MR images, five tumors had high signal intensity and two had low signal intensity. Eleven tumors were not visualized. Tumors with fatty change and/or clear cell formation were frequently hyperechoic on US and hyperintense on T1-weighted MR images. CONCLUSIONS: Well-differentiated HCCs show different findings on US, CT, and MR imaging. Therefore, reliable diagnosis of well-differentiated HCCs by these imaging techniques may be difficult.

Aged↗