Biomedical subjects

T Shima

Publications and source records attributed to T Shima.

At least 55 records · Page 3Linked to original sources

PubMed1998

Bile acids influence hepatic chemiluminescence in normal and oxidative-stressed rats.

The aim of the present study was to clarify whether bile acids influence chemiluminescence (CL) in the liver in vivo. Hepatic CL was determined on the surface of the liver of anaesthetized rats by using a photon counter. In normal rats, hepatic CL was significantly decreased 30 min after enteral administration of chenodeoxycholic acid (CDCA) or deoxycholic acid (DCA), but returned to its initial level 3 h later, after part of the CDCA administered was metabolized. Ursodeoxycholic acid (UDCA) and cholic acid had no effect on CL. In contrast, hepatic CL was markedly increased 30 min after CDCA or DCA administration in rats given either buthionine sulphoximine (BSO), an inhibitor of gamma-glutamylcysteine synthetase, or diethyldithiocarbamate (DDC), an inhibitor of both superoxide dismutase and glutathione peroxidase. Chenodeoxycholic acid further increased the CL of BSO- or DDC-treated rats during inhalation of oxygen via a tracheal cannula. Coadministration of UDCA eliminated the effects of CDCA on the hepatic CL of normal and BSO- or DDC-treated rats with or without oxygen inhalation. We conclude that cytotoxic bile acids, such as CDCA, increase CL in the antioxidants-depleted or oxidative-stressed liver in vivo, but that UDCA prevents CDCA from developing CL.

Animals↗

PubMed1998

Effectiveness of superficial temporal artery-middle cerebral artery anastomosis in adult moyamoya disease: cerebral hemodynamics and clinical course in ischemic and hemorrhagic varieties.

BACKGROUND AND PURPOSE: The efficacy of superficial temporal artery-middle cerebral artery (STA-MCA) anastomosis in adult moyamoya disease was evaluated by clinicopathophysiological studies. METHODS: Fifteen patients with cerebral ischemic attacks (ischemia group) and 15 patients with intracranial hemorrhages (hemorrhage group) were investigated. Clinicoangiographic features and regional cerebral blood flow (rCBF) of the MCA territory were preoperatively and postoperatively investigated, and cortical arterial pressure (CAP) and anastomotic blood flow (AF) were intraoperatively measured. RESULTS: In the ischemia group, the preoperative rCBF of 38.4 mL/100 g per minute was significantly increased to 42.1 mL/100 g per minute with a diminution of angiographic moyamoya vessels in 67% of patients after surgery. The mean CAP and AF were 25.6 mm Hg and 34.7 mL/min, respectively. Proximal and distal cerebral vascular resistance (PCVR = [Mean Systemic Arterial Blood Pressure-Mean CAP]/rCBF and DCVR = [Mean CAP/rCBF]) were 1.78 and 0.68, respectively. One patient died perioperatively as a result of intracerebral hemorrhage. During follow-up (mean, 67 months), 12 of 14 patients recovered without neurological deficits, 1 was moderately disabled because of the initial insult, and another patient experienced an intracerebral hemorrhage but recovered fully. In the hemorrhage group, the preoperative rCBF of 38.0 mL/100 g per minute was significantly increased to 42.7 mL/100 g per minute with a diminution of moyamoya vessels in 60% after surgery. The mean CAP and AF were 29.1 mm Hg and 24.1 mL/min, respectively. PCVR and DCVR were 1.72 and 0.77, respectively. One patient became hemiparetic because of perioperative intracerebral hemorrhage. During follow-up (mean, 94 months), 3 patients had fatal intracranial hemorrhages, 10 had good recoveries, and 2 had moderate disabilities. CONCLUSIONS: This study revealed a high PCVR and a very low DCVR in both the ischemia and hemorrhage groups of patients. STA-MCA anastomosis partially normalized cerebral circulation and decreased moyamoya vessels but did not completely prevent rebleeding.

Adult↗

PubMed1998

The relation between the pacing sites in the right ventricular outflow tract and QRS morphology in the 12-lead ECG.

Optimal pace mapping is a good predictor of the appropriate ablation site for idiopathic right ventricular tachycardia (VT) originating from the right ventricular outflow tract (RVOT). We studied the relationship between the RVOT pacing site and QRS morphology in the 12-lead ECG during pacing to find the optimal site more quickly. In 13 patients with idiopathic VT, pacing at 8 sites in the RVOT (free wall, septum, and anterior and posterior regions of upper and lower sites) was performed while 12-lead ECGs were recorded. The R-wave amplitude minus the S-wave amplitude in lead I (RI-SI) and aVF (RavF-SavF) and the transitional zone index (TZI) were compared in the different pacing sites; TZI was defined to examine the transitional zone as a value. The RI-SI was smaller in the anterior region than in the other regions, and the negative RI-SI predicted that the pacing site was in the upper or lower anterior regions. The RavF-SavF was larger in the septum and anterior regions than in the free wall and posterior regions. The TZI was larger in the free wall region than in the septum. From the results, we constructed a flow chart that differentiates the origin of the arrhythmia in the RVOT and a directional guide that indicates the direction from the current mapping site for optimal pace mapping. The results provided an ECG guide for locating the focus of VT originating from the RVOT. These findings may systematically improve the mapping procedure.

Adolescent↗

PubMed1998

Magnetic resonance angiography visualization of four vessel (bilateral carotid and vertebral artery) occlusion--two case reports.

A 44-year-old female with transient vertigo and a 51-year-old female with headache and numbness of the hand presented with four vessel occlusion of the cerebral arteries (bilateral internal carotid arteries and bilateral vertebral arteries). This is an extremely rare entity, and the clinicoradiological features are not well documented. Magnetic resonance (MR) angiography visualized the cerebral arterial occlusion. Conventional angiography confirmed the diagnosis and demonstrated extensive collateral vessels. MR angiography is a useful method for screening patients with minimal or no symptoms for abnormalities in the cerebral circulation.

Adult↗

PubMed1998

Subarachnoid hemorrhage caused by Aspergillus aneurysm as a complication of transcranial biopsy of an orbital apex lesion--case report.

A 62-year-old male complaining of unilateral visual disturbance and pain in the involved eye had a small mass at the right orbital apex which was identified as an Aspergillus granuloma by transcranial biopsy. One month later, the patient became comatose because of fatal subarachnoid hemorrhage due to a newly developed aneurysm. Autopsy showed a ruptured aneurysm on the right internal carotid-posterior communicating artery. Histological examination demonstrated prominent Aspergillus invasion of the arterial wall. Aspergillus infection must be taken into consideration in patients with orbital apex syndrome, which may lead to serious cerebrovascular consequences. If sino-orbital lesions are detected by neuroimaging techniques, biopsy using an extradural approach should be performed to obtain a definitive diagnosis.

Aneurysm, Infected↗

PubMed1998

[Spinal anesthesia in a patient with spina bifida occulta].

A 32-year-old woman with spina bifida occulta was scheduled for hemorroidectomy under spinal anesthesia. Preoperatively, computed tomography and magnetic resonance imaging (MRI) were performed. The MRI demonstrated the conus medul laris reaching the L 3 level and a lipoma connected with conus medullaris intrathecally. Spinal anesthesia was done successfully at the L 3-4 interspace using 0.3% dibucaine 1.2 ml with 5% glucose 0.8 ml. Postoperatively she showed no neurologic complications. With exact anatomical findings of MRI, spinal anesthesia can be safely performed for patients with spina bifida occulta.

Adult↗

PubMed1998

[Effect of somatosensory disturbance to outcomes of motor function in thalamic hemorrhage: evaluation with short-latency somatosensory evoked potential (SSEP)].

We investigated the effect of the somatosensory functions to the outcomes of motor functions in 28 patients with thalamic hemorrhage. The disturbance of the pyramidal tracts was assessed by the destruction of the internal capsule found in computed tomography (CT). The disturbance of the somatosensory function was analyzed by the N20 component of short-latency somatosensory evoked potentials (SSEP). The outcomes of motor function was evaluated after 3 months of ictus. Correlations between the outcomes of motor function, disturbance of the pyramidal tract, and disturbance of the somatosensory function were discussed. The result indicated that functional outcomes statistically correlated with neither disturbance of the internal capsule alone nor disturbance of N20 alone. But, there was statistically significant between functional outcomes and the combination of disturbance of the internal capsule with disturbance of N20 (p < 0.05, Wilcoxon signed-rank). There was not statistical difference in hematoma volume or consciousness. The implications of these results suggest that somatosensory function may affect the recovery of motor functions.

Aged↗

PubMed1998

[Macroscopic and pathohistological investigation of endarterial plaque after intraoperative balloon dilatation of the carotid artery during carotid endarterectomy].

Twelve patients associated with stenosis of the extracranial carotid artery underwent intraluminal balloon dilatation during carotid endarterectomy (CEA). There were 11 men and 1 woman, and age ranged from 56 to 73 years old. The rate of stenosis, shown by angiography, in each patient was from 60 to 85% in width. After securing carotid blood flow by a T-shaped shunt tube, a balloon catheter was inserted from the exposed common carotid artery into the internal carotid artery. The balloon was inflated three or four times with 2.5-3.5 atm. for 30-40 seconds. Immediately after balloon dilatation, endoscopic investigation was performed (Wolf; hard type endoscope, 2.7 mm diameter). Then CEA was performed using the usual procedure. The removed endarterial plaque was investigated pathohistologically. In macroscopic and endoscopic findings, there were 6 patients with mural thrombosis, 4 patients with laceration of the intima, and one patient with outflow of atheroma from the intima. Only 3 patients had increase in lumen after balloon dilatation. In pathohistological appearance, all patients had a moderate degree of fibrosis, calcification, and atheroma in the cross section of the plaque. Ten patients had intramural hemorrhage. Three typical patients were revealed by the use of angiographical, ultrasonographical, endoscopic, and pathohistological presentation. Case 10 showed laceration of the intima by balloon dilatation, and had moderate increase in lumen size macroscopically and endoscopically. There were moderate cases of fibrosis, calcification, atheroma, and intramural hemorrhage. Dilatation of the lumen seemed to be accomplished by a decrease in thickness of the atheroma and intramural hemorrhage. Case 8 demonstrated an increase in lumen size, but also laceration of the intima and outflow of atheroma from the arterial wall. There were much atheroma and large intramural hemorrhage in the intima, which might become a source of enbolism. Case 7 revealed no laceration of the intima and no increase in lumen size. Preoperative ultrasonography showed hyperechoic finding and postoperative pathohistological findings showed severe fibrosis and calcification, which were thought to have interrupted balloon dilatation. There have been small numbers of reports about pathohistological presentation after percutaneous transluminal angioplasty (PTA), because it is very difficult to take a specimen after PTA. In this report we were able to present the necessity of preoperative investigations by angiography, ultrasonography, and 3D-CT.

Aged↗

PubMed1998

Continuous monitoring of jugular bulb venous oxygen saturation for evaluation of cerebral perfusion during carotid endarterectomy.

In this study we examined whether continuous monitoring of jugular bulb venous oxygen saturation (SjO2) is applicable for the evaluation of cerebral hypoperfusion during carotid endarterectomy (CEA). The subjects were 25 patients who underwent elective CEA under general anaesthesia. After the carotid stump pressure (SP) was measured, SjO2 and the somatosensory evoked potentials (SEP) were monitored during the carotid test clamping for 10 min. There was no alteration in cardiovascular and respiratory status during the test clamping. No correlation was observed between SEP amplitude and SP (r = 0.16, p = 0.25). However, at clamping, SjO2 decreased from 70 to 64% (p < 0.01) with a reduction in SEP amplitude from 2.0 to 1.6 microV (p < 0.01). After declamping, SjO2 increased from 65 to 70% (p < 0.01) with a recovery in SEP from 1.6 to 1.9 microV (p < 0.01). The changes in SEP amplitude and SjO2 correlated (r = 0.66, p < 0.001). These results suggest that continuous monitoring of SjO2 is superior to SP measurement in the prediction of cerebral hypoperfusion caused by carotid clamping and applicable to CEA.

Cerebrovascular Circulation↗

PubMed1997

Increased expression of interleukin-2 receptor alpha on peripheral blood mononuclear cells in HTLV-I tax/rex mRNA-positive asymptomatic carriers.

Using the double-nested reverse transcription-polymerase chain reaction, we assayed human T-cell leukemia virus type I (HTLV-I) tax/rex-encoded mRNA in the peripheral blood mononuclear cells (PBMCs) of asymptomatic carriers as an index of the expression of HTLV-I in vivo in relation to the proviral DNA level. HTLV-I tax/rex mRNA was detected in only 1 (3.3%) of 30 samples with medium or lower proviral DNA levels, but it was detected in 11 (39.3%) of 28 samples with high HTLV-I proviral DNA levels, estimated as equal to or more than the proviral DNA of 10 ng of HUT102 (i.e., HUT102 cells were used as positive controls). The mean number of interleukin-2 receptor alpha (IL-2R alpha)-positive cells as a percentage of the total number of PBMCs was higher (13.2%) in the tax/rex mRNA-positive carriers with high proviral DNA levels than in the carriers who were mRNA negative (8.4%) (p = 0.004, Wilcoxon test). These results suggest that virus activation as indicated by the presence of tax/rex mRNA in asymptomatic carriers with high proviral DNA levels is associated with an elevation of the IL-2R alpha-positive cells in vivo.

Carrier State↗

PubMed1997

Melatonin suppresses hyperglycemia caused by intracerebroventricular injection of 2-deoxy-D-glucose in rats.

To elucidate the role of melatonin (MT), we examined the effects of intracranial injection of MT and an MT-antagonist (S20928) on the hyperglycemic response to intracranial injection of 2-deoxy-D-glucose (2DG) in rats. The hyperglycemic and hyperglucagonemic responses caused by intracerebroventricular injection of 2DG were inhibited by intracerebroventricular co-injection of MT, but enhanced by co-injection of the MT-antagonist. Intraperitoneal injection of MT also inhibited the hyperglycemic response, though the inhibition seemed to be less than that after intracranial injection of MT. These results suggest that MT plays an endogenously suppressive role in the hyperglycemia caused by 2DG, possibly through a brain site.

Animals↗

PubMed1997

Serum 7S domain of type IV collagen levels in essential hypertension and hypertensive type 2 diabetic patients.

Metabolic alteration of Type IV collagen occurs in micro- or macrovascular basement membrane of diabetic patients. Hypertension, a risk factor for clinical progression of diabetic vascular disease, may influence this metabolic alteration. The object of this study was to evaluate the serum 7S domain of type IV collagen (7S-collagen) levels in patients with essential hypertension and in Type 2 diabetic patients with or without hypertension and to investigate the relationship between the type IV collagen metabolism and the arterial blood pressure. Serum 7S-collagen levels in 18 patients with essential hypertension were significantly higher than in 24 normal subjects (4.2 +/- 0.5 vs 3.6 +/- 0.4 ng ml(-1) p < 0.01). Serum 7S-collagen levels in 28 normotensive diabetic patients (4.2 +/- 0.5 ng ml(-1)) were significantly higher than in normal subjects (p < 0.01). The serum 7S-collagen levels were significantly higher in 22 diabetic patients with hypertension (4.8 +/- 0.6 ng ml(-1)) than in the other groups. There was a significant correlation between the serum 7S-collagen levels and the systolic blood pressure in cases with essential hypertension (r = 0.59, p < 0.001) and in all diabetic patients (r = 0.52, p < 0.001), suggesting that elevation of the systolic blood pressure may influence the type IV collagen metabolism of vascular basement membrane. We conclude that the metabolic alteration of basement membrane occurring in patients with diabetes mellitus may worsen in the presence of high systolic blood pressure.

Age Factors↗

PubMed1997

Immortalization of mutant p53-transfected human fibroblasts by treatment with either 4-nitroquinoline 1-oxide or X-rays.

The study of in vitro cell transformation is valuable for understanding the multistep carcinogenesis of human cells. The difficulty in inducing neoplastic transformation of human cells by treatment with chemical or physical agents alone is due to the difficulty in immortalizing normal human cells. Thus, the immortalization step is critical for in vitro neoplastic transformation of human cells. We transfected a mutant p53 gene (mp53: codon 273Arg-His) into normal human fibroblasts and obtained two G418-resistant mp53-containing clones. These clones showed an extended life span but ultimately senesced. However, when they were treated with either 4-nitroquinoline 1-oxide or X-rays, they were immortalized. The immortalized cells showed both numerical and structural chromosome abnormalities, but they were not tumorigenic. The expression of mutant but not wild type p53 was detected in the immortalized cells by RT-PCR. Expression of p21, which is located downstream of p53, was remarkably reduced in the immortalized cells, resulting in increased cdk2 and cdc2 kinase activity. However, there was no significant difference between the normal and immortalized human cells in expression of another tumor suppressor gene, p16. These findings indicate that the p53-p21 cascade may play an important role in the immortalization of human cells.

4-Nitroquinoline-1-oxide↗

PubMed1997

Effect of triiodothyronine on glucose transport in rat adipocytes.

The in vitro effect of thyroid hormones on glucose transport in insulin-stimulated muscle cells or adipocytes is still unclear. The objective of the present study was to assess the direct effect of 3,3',5-triiodothyronine (T3) on glucose transport and on the translocation of insulin-regulatable glucose transporter (GLUT4) in insulin-stimulated rat adipocytes. This evaluation was performed using an in vitro assay to avoid the well-known systemic effects of this hormone ( e.g.: hyperinsulinemia). Adipocytes were isolated from epididymal adipose tissue of Sprague-Dawley rats. Glucose transport assay and immunoblot analysis of GLUT4 were carried out in insulin-stimulated and unstimulated adipocytes after treating with or without T3. The results were as follows; 1) T3 inhibited the glucose transport in insulin-stimulated and unstimulated adipocytes in a dose-dependent manner. 2) T3 decreased the maximal response level (Vmax) but did not alter the sensitivity (Km) of glucose transport to insulin. 3) T3 did not affect the translocation of GLUT4 from the intracellular pool to the plasma membrane. We concluded that T3 inhibits the glucose transport in insulin-stimulated adipocytes in a post-receptor level without affecting the translocation of GLUT4 from the intracellular pool to the plasma membrane. This suggests that T3 acts by decreasing the intrinsic activity or the accessibility of GLUT4 in the plasma membrane.

3-O-Methylglucose↗

PubMed1997

Binding of iron to neuromelanin of human substantia nigra and synthetic melanin: an electron paramagnetic resonance spectroscopy study.

The binding of iron by melanin is a potentially important phenomenon as detailed knowledge of this binding is essential for understanding the role of melanin and iron in the pathogenesis of oxidative damage in the substantia nigra. Electron paramagnetic resonance spectroscopy is one of the most useful approaches in the investigation of melanins and their interaction with iron. This study was undertaken to obtain systematic data on the effects of ferric iron on the electron paramagnetic resonance spectra of neuromelanin and synthetic models of neuromelanin. Data from the latter can potentially be used to infer as to the state of neuromelanin in the human substantia nigra. The results of this study indicate that the spectra at g = 4.3, attributable to Fe3+, provides a useful parameter for determining the amount of paramagnetic iron bound to melanin. These data together with the magnitude of the free radical signal from melanin provides an indication of the amount of iron bound to neuromelanin in intact human substantia nigra. After binding to melanin, the iron can change its location and/or state, which is indicated by the change in the microwave power saturation that occurs gradually after the binding of the iron. At least part of this process could occur at low temperatures (i.e., during storage at -15 degrees C).

Adult↗

PubMed1997

Large sixth nerve neuroma involving the prepontine region: case report.

OBJECTIVE AND IMPORTANCE: Tumors originating from the cranial nerves are uncommon, except for the acoustic and trigeminal neuromas. The sixth nerve, however, has the potential to generate neuromas with characteristic clinical features. CLINICAL PRESENTATION: A 54-year-old woman presented with diplopia and increased intracranial pressure. Magnetic resonance imaging showed a large mass in the prepontine region. Surgery was performed via a condylar approach and demonstrated a tumor originating from the prepontine portion of the sixth nerve. CONCLUSION: The sixth nerve neuroma at the pontomedullary junction showed characteristic clinical features and could be successfully removed via a condylar approach.

Abducens Nerve↗

PubMed1997

Abnormal metabolism of type-IV collagen in normotensive non-insulin-dependent diabetes mellitus patients.

The objective of this study was to investigate the serum level of the 7S domains of type-IV collagen [IVc(7S)] and its relations with microangiopathy in non-insulin-dependent diabetes mellitus (NIDDM). This study comprised 73 patients with NIDDM that were consulted in our outpatient clinic. Among the 73 NIDDM patients, 43 with normal arterial pressure were selected to assess the relationship between serum levels of 7S collagen and microangiopathy. There was a significant relationship between the serum IVc(7S) levels and the presence of retinopathy and nephropathy. These findings suggest that an increased IVc (7S) concentration may reflect the abnormal collagen metabolism of the vascular basement membrane in NIDDM patients. Column chromatography of the NIDDM patients' sera revealed the heterogeneity of immunoreactive type-IV collagen (7S) and showed that these domains were composed mainly of degradation products of type-IV collagen. These data suggest that degradation of IVc is accelerated in the vascular basement membrane of NIDDM patients.

Chromatography↗

PubMed1997

Combined inhalation of nitric oxide and oxygen in chronic obstructive pulmonary disease.

Inhaled nitric oxide (NO) has been shown to reduce the mean pulmonary artery pressure (mPAP) and to improve PaO2 in patients with acute respiratory failure undergoing oxygen (O2) therapy. However, inhaled NO reduced pulmonary hypertension without improving PaO2 in patients with chronic obstructive pulmonary disease (COPD). This study was intended to compare the hemodynamic and gas exchange responses during inhalation of NO or O2 with those observed during the combined inhalation of NO and O2 in 10 spontaneously breathing COPD patients. Hemodynamic and blood gas parameters were measured after breathing: (1) room air; (2) NO added to room air; (3) O2 (1 L/min); or (4) NO and O2. During inhalation of 2 ppm NO added to room air, the mPAP (23.1 +/- 2.5 versus 20.6 +/- 2.2 mm Hg) and the pulmonary vascular resistance (PVR) (434 +/- 70 versus 378 +/- 50 dyne s/cm5) were significantly (p < 0.05) lower than those measured with room air. However, the values of PaO2 did not improve. The combined inhalation of NO and O2 was associated not only with a significant (p < 0.05) decrease of mPAP (21.4 +/- 2.3 versus 19.7 +/- 1.8 mm Hg) and PVR (431 +/- 72 versus 370 +/- 44 dyne s/cm5), but also with a remarkable improvement (p < 0.05) in the values of PaO2 (91.4 +/- 6.6 versus 111.5 +/- 7.8 mm Hg) as compared with values obtained during the inhalation of O2 alone. These findings suggest that combined therapy with NO and O2 may constitute an alternative approach to treating patients with COPD and pulmonary hypertension.

Administration, Inhalation↗