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Biomedical subjects

Y Okada

Publications and source records attributed to Y Okada.

At least 559 records · Page 31Linked to original sources
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

[Determinants of long-term outcome for operative survivors of acute aortic dissection].

Predictability of aorta-related complications and survival was examined in 79 operative survivors of acute aortic dissection. Follow-up was 94.9% complete and totaled 458 patient-years. Actuarial survival was 93 +/- 3% (+/- S.E.) (n = 43) at 5 years, and 74 +/- 8% (n = 13) at 10 years. Survival was significantly lower in patients having neurological complication. Freedom from aorta-related complications was 82 +/- 5% (n = 37) at 5 years, and 67 +/- 8% (n = 11) at 10 years. Multivariate Cox regression analysis identified residual entry and leak on anastomotic site as independent predictors of aorta-related complications. We conclude that in the treatment of acute aortic dissections, reducing the incidence of residual entry and leak on anastomotic site improves long-term outcome.

Acute Disease↗
PubMed1998

Expression and tissue localization of membrane-types 1, 2, and 3 matrix metalloproteinases in human urothelial carcinomas.

PURPOSE: Three different membrane-type matrix metalloproteinases (MT1, 2, 3-MMP) which can activate proMMP-2 (progelatinase A) are thought to have an important role in various human carcinoma invasions and metastases. We examined the mRNA expression of MT-MMPs and the tissue immunolocalization of MT1-MMP in human urothelial carcinomas. MATERIALS AND METHODS: mRNA was extracted from 27 clinical urothelial carcinomas and 10 normal urothelial mucosa tissues remote from the tumor. RT-PCR using specific primers was performed, and PCR products were hybridized to 32P-labeled internal probes and analyzed by a bioimage analyzer. Immunolocalization was studied using a monoclonal antibody against MT1-MMP (114-6G6). RESULTS: MT1-MMP and MT2-MMP mRNA expressions in urothelial carcinomas were significantly higher than those in the normal mucosa. In contrast, MT3-MMP mRNA was little expressed in both tissues, and the amount of MT3-MMP mRNA appeared to be much lower than MT1-MMP and MT2-MMP in the tissue samples. In terms of the tumor multiplicity, MT1-MMP and MT2-MMP mRNA expressions in the group of multiple tumors were significantly higher than those in the solitary tumor group. The carcinoma cells were immunostained for MT1-MMP predominantly in invasive and superficial carcinoma cells. The immunoreactivity was more intense in the invasive type than in the superficial type. CONCLUSIONS: It is suggested that MT1-MMP and MT2-MMP play an important role in the development of human urothelial carcinomas and reflect some aspects of the pathogenesis of multifocal occurrence. In spite of the possible contribution to the invasive and metastatic phenotype, MT1-MMP mRNA and its product are thought to be expressed already in the clinical superficial stage in some cases of this tumor type.

Carcinoma, Transitional Cell↗
PubMed1998

[Use of the radial artery graft in coronary artery bypass grafting: harvesting technique and spasm prevention].

The use of radial artery (RA) in coronary artery bypass grafting (CABG) has been increasing recently as a revival. In this report, we describe several practical suggestions for improving patency rate of the graft. Between April of 1997 and February of 1998, 41 CABGs were performed using RA graft, totalling 56 anastomoses. The early patency rate of the graft has been 100% (graft: 38/38, anastomosis: 53/53). Harvesting technique: with the use of Harmonic Scalpel, it is possible to atraumatically harvest the vessel in a short time. Although longitudinal fasciotomy of the adventitia has been recently reported to be effective in releasing spasm, the nature of the vessel raise concern that the fasciotomy may even induce spasm. We hypothesize that leaving the adventitia intact, preserving vasa vasorum, rather than performing fasciotomy leads to improvement of long-term patency. Spasm prevention: we consider the body temperature to be the most important factor. Therefore, we utilize normothermic cardiopulmonary bypass (CPB). Another important factor is that the arterial CO2 is kept at a high level during CPB. For dilation of RA graft, milrinone is used instead of papaverine. For the intra- and postoperative management, intravenous continuous administration of diltiazem was changed to nicorandil. Technically, essential resolution for improvement of patency rate is either to allow for large proximal anastomosis, or to make sequential anastomosis with another coronary artery which has a good run off. For these purposes, the proximal anastomosis on the ascending aorta seems to have the advantage over placing it on ITA.

Adult↗
PubMed1998

[Postoperative chylothorax treated with fibrin glue and absorbent mesh: a case report].

A 66-year-old man was treated by graft replacement for a thoracic aortic aneurysm. Chylothorax occurred on postoperative day 2. In spite of cessation of oral intake and IVH management, chest tube drainage did not decrease, the patient became malnourished. A chest X-ray and CT scan revealed the massive pleural effusion. Reoperation assisted with a thoracoscopy was carried out for chylothorax on postoperative day 27. Because we were unable to find the thoracic duct and the leakage point, the fibrin glue and absorbent mesh was applied to parietal and mediastinal pleura. Four days after reoperation, the chest tube was removed. This method is useful for this type of a chylothorax and lymphorrhea.

Absorption↗
PubMed1998

[Expression of major histocompatibility complex antigens and adhesion molecules on renal cell carcinoma cells, and effect of interferon-alpha and/or cimetidine on the expression].

Recently the combined therapy with interferon-alpha (IFN-alpha) and cimetidine has been reported to be effective against advanced renal cell carcinoma (RCC). IFN-alpha and cimetidine have an antitumor effect partly due to enhancement of cytotoxic activity of lymphocytes against cancer cells. We examined the expression of major histocompatibility complex (MHC) antigens and adhesion molecules on 4 fresh RCC cells and 5 RCC cultured cell lines, which have an important role in recognition and killing of cytotoxic lymphocytes against cancer cells. The effect of treatment with IFN-alpha and/or cimetidine on the expression of MHC antigens and adhesion molecules on RCC cells was also investigated. MHC class I and leukocyte function-associated antigen-3 (LFA-3) were expressed on all RCC cells, but not MHC class II. Intercellular adhesion molecule-1 (ICAM-1) and B7 were expressed on 6 and 5 of 8 RCC cells, respectively. IFN-alpha significantly augmented the expression of MHC class I in 6 of 9 RCC cells, ICAM-1 in 1 and LFA-3 in 2 of 8 RCC cells. However, IFN-alpha did not affect the expression of MHC class II and B7. On the other hand, cimetidine enhanced the expression of LFA-3 in 2 of 8 RCC cells, but not MHC antigens, ICAM-1 or B7. The combination of IFN-alpha and cimetidine did not show a synergistic enhancing effect on the expression of MHC antigens, ICAM-1, LFA-3 or B7. These results suggest that IFN-alpha augments the sensitivity of RCC cells to lysis by cytotoxic lymphocytes partly due to the enhancement of expression of MHC class I, ICAM-1 and LFA-3 on RCC cells, and that cimetidine also augments the susceptibility of RCC cells to lymphocytes by the enhanced expression of LFA-3 on RCC cells.

Adjuvants, Immunologic↗
PubMed1998

[Aortic arch replacement and elephant trunk method for thoracic aneurysm].

A 73-year-old female with ischemic heart disease and thoracic aneurysm from the ascending aorta to the descending aorta underwent coronary bypass and aortic arch replacement combined with the elephant trunk method with the aid of extracorporeal circulation and selective cerebral perfusion. The graft provided with four limbs for arch replacement was inverted in advance. The ascending aorta was cross-clamped following extracorporeal circulation. The anastmosis of the left internal thoracic artery to LAD was continuously performed by 8/0 prolene. As the elephant trunk 11 cm in length of the inverted graft was inserted into descending aorta after the arch and descending aorta were opened. The inverted end of the graft was sutured to the aorta beyond the origin of the left subclavian artery. The inverted end of graft with four limbs was then withdrawn. Brachiocephalic vessels were reconstructed during rewarming. The patient recovered well without any cerebral complications. Aortogram made after operation showing proximal aortic replacement and a segment dangling in the distal aneurysm surrounded with thrombus.

Aged↗
PubMed1998

Alteration of the GABAergic neuronal system of the retina and superior colliculus in streptozotocin-induced diabetic rat.

Diabetes mellitus (DM) often causes neural dysfunctions, including visual disorders. To investigate the effect of hyperglycemia on the visual system, we studied the metabolism of gamma-aminobutyric acid (GABA), a major inhibitory neurotransmitter that has an important role in visual functions. We determined the GABA content and activities of glutamate decarboxylase (GAD) and GABA transaminase (GABA-T) in the retina and superior colliculus (SC) in streptozotocin (STZ)-induced DM rats. The GABA content and activities of GAD and GABA-T were decreased in the retinas of STZ-treated rats. The GABA content and GAD activity were reduced in the SC of STZ-treated rats, whereas GABA-T activity showed no marked change. This GABA reduction in the diabetes may be correlated with visual dysfunctions.

4-Aminobutyrate Transaminase↗
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

[Synchronous multifocal development of invasive transitional cell carcinoma of the urinary tract in a patient with renal failure receiving long-term hemodialysis: a case report].

We report a case of transitional cell carcinoma in a patient with chronic renal failure receiving hemodialysis for 22 years. A 55-year-old man was admitted to our hospital. Under diagnosis of invasive bladder cancer and left renal pelvic tumor, removal of the whole urinary tract, e.g., bilateral nephroureterectomy and total cystourethrectomy was performed. Transitional cell carcinoma was found in bilateral renal pelvis, left ureter, bladder and prostate in the resected specimen. Thirteen months after the operation, multiple lung metastases and pathologic bone fracture of the 4th lumber vertebra were found. Chemotherapy (3 courses of modified CISCA, consisting of cisplatin, adriamycin and cyclophosphamide) was performed, but the died of systemic metastases of cancer and bleeding due to perforation of multiple gastric ulcers.

Carcinoma, Transitional Cell↗
PubMed1997

Inhibition of gene expression from the human c-erbB gene promoter by a retroviral vector expressing anti-gene RNA.

Anti-gene is a potent inhibitor of transcriptional promoter activity and subsequent gene expression. This property has been exploited to suppress the expression of a variety of oncogenes for regulating tumor proliferation or viral activities. In this paper, we describe a novel retroviral vector designed to express human c-erbB anti-gene RNA and to reduce the promoter activity in the cells. Mouse fibroblast NIH3T3 cells were stably transfected with an expression construct containing a truncated human c-erbB gene promoter fused to the firefly luciferase reporter gene. Infection into these cells of the c-erbB anti-gene retroviral vector targeted to the 26 bp pyrimidine-rich element in the human c-erbB gene promoter resulted in a dose-dependent decrease in the luciferase activity of the cells. Retroviral vector expressing anti-gene RNA may be useful as an alternative program of gene regulation in the cells.

3T3 Cells↗
PubMed1997

Accumulation of platelets in rat syngeneic lung transplants: a potential factor responsible for preservation-reperfusion injury.

BACKGROUND: Platelets are known to play an important role in the pathogenesis of adult respiratory distress syndrome as well as preservation-reperfusion injury of liver allografts. However, the role of platelets in pulmonary preservation-reperfusion injury is unknown. In this study, we examined whether the extent of platelet accumulation in the preserved and subsequently reperfused lungs correlated with the degree of preservation-reperfusion injury in a rat lung isotransplant model. METHODS: Heart-lung blocks from donor rats were flushed with and preserved in modified Euro-Collins solution at 4 degrees C for 0 hr (n=5), 6 hr (n=6), and 24 hr (n=6). The left lung was divided from the heart-lung block, transplanted into the recipient rat, and reperfused for 1 hr. Lung injury was evaluated by the left-to-right pulmonary blood flow ratio, the weight gain of the isograft, and the scores for histological categories of lung injury (intra-alveolar edema, intra-alveolar hemorrhage, and capillary congestion). Small portions of the lung isograft were excised and stained with an antibody specific for rat platelets. A scoring system was developed to semiquantitate the intensity of antibody staining in isografts. RESULTS: Lung isografts were injured and platelets accumulated in the capillaries in proportion to the length of preservation endured before transplantation. The extent of platelet accumulation evaluated by our morphological scoring system correlated significantly with the degree of lung injury assessed by the blood flow ratio (P<0.001), the weight gain (P<0.001), and the histological scores for intra-alveolar hemorrhage (P<0.05) and for capillary congestion (P<0.001). CONCLUSIONS: The results of this study suggest that platelet accumulation is a potential factor responsible for preservation-reperfusion injury of lung isografts in the rat.

Animals↗
PubMed1997

Neural activity and intracellular Ca2+ mobilization in the CA1 area of hippocampal slices from immature and mature rats during ischemia or glucose deprivation.

To investigate the correlation between neural activity and intracellular Ca2+ ([Ca2+]i) mobilization in immature and adult brain during ischemia (hypoxia and glucose deprivation) and deprivation of glucose, hippocampal slices were prepared from 7-, 10-day-old and adult rats. Population spikes (PS) and antidromic responses (AR) were recorded in the pyramidal cell layer of the CA1 area as an index of neural function. [Ca2+]i mobilization of the stratum radiatum in the CA1 area was measured using the fluorescent dye fura-2 AM. The rise in [Ca2+]i occurred earlier in the adult animal and the decay times for the orthodromic PS and antidromic responses were shorter in the adult during ischemia. The field potentials and antidromic responses decreased substantially prior to the elevation of [Ca2+]i in both developing and adult brains. Furthermore, ATP levels decreased substantially before the elevation of [Ca2+]i during ischemia. These results suggest that neural activity and intracellular Ca2+ homeostasis in the immature rats brain are more resistant to energy failure than adult rats and that neuronal activity in the developing and adult brain is impaired initially by energy depletion during ischemia. In the immature animal, during glucose deprivation, the antidromic responses were slowly decayed or even failed to extinguish and [Ca2+]i levels were maintained for a longer period or even failed to rise in spite of the rapid loss of PS. Furthermore, ATP levels were well preserved at the time of PS loss. These results agree well with our previous reports showing that glucose plays an important role in the preservation of synaptic transmission in addition to its major function as an energy substrate.

Aging↗
PubMed1997

Identification and classification of 16 new kinesin superfamily (KIF) proteins in mouse genome.

KIF (kinesin superfamily) proteins are microtubule-dependent molecular motors that play important roles in intracellular transport and cell division. The extent to which KIFs are involved in various transporting phenomena, as well as their regulation mechanism, are unknown. The identification of 16 new KIFs in this report doubles the existing number of KIFs known in the mouse. Conserved nucleotide sequences in the motor domain were amplified by PCR using cDNAs of mouse nervous tissue, kidney, and small intestine as templates. The new KIFs were studied with respect to their expression patterns in different tissues, chromosomal location, and molecular evolution. Our results suggest that (i) there is no apparent tendency among related subclasses of KIFs of cosegregation in chromosomal mapping, and (ii) according to their tissue distribution patterns, KIFs can be divided into two classes-i.e., ubiquitous and specific tissue-dominant. Further characterization of KIFs may elucidate unknown fundamental phenomena underlying intracellular transport. Finally, we propose a straightforward nomenclature system for the members of the mouse kinesin superfamily.

Amino Acid Sequence↗
PubMed1997

The effects of lactate and beta-hydroxybutyrate on the energy metabolism and neural activity of hippocampal slices from adult and immature rat.

We investigated the correlation between energy metabolism and neural activity during glucose deprivation and during replacement of glucose with lactate and beta-hydroxybutyrate (OHBA) in neural tissue from rats of different ages. Hippocampal slices were prepared from 4-, 7-, 10-, 13- and 16-day-old and adult rats. The population spikes (PS) were recorded in the pyramidal cell layer of the CA3 area as the index of neural activity. ATP and creatine-phosphate (CrP) levels in each slice were determined during glucose deprivation and during replacement of glucose with lactate or OHBA. After deprivation of glucose, the PS of the slices from 4-, 7- and 10-day-old and adult rats decayed and extinguished in 30 min and the decay time was shortened according to the age of the rat. The levels of ATP and CrP in the slices also decreased, but to a lesser extent than the amplitudes of PS. After substitution of lactate or beta-hydroxybutyrate (OHBA) for glucose, PS of the adult rat disappeared as was the case with glucose deprivation, although the levels of high energy phosphates were well maintained. In the case of the immature rat, however, PS decayed more slowly. Especially in the case of 4-day-old rat, ATP and CrP in the slices were maintained as high as those under the initial concentrations and PS amplitude showed no decay even after 60 min. These results indicate that the presence of glucose is essential for neural activity in the adult rat, and lactate or OHBA cannot replace it for the maintenance of neural activity. In the immature rat, glucose metabolites such as lactate and OHBA are available for both neural activity as well as maintaining the levels of high-energy phosphates in the tissue slice.

3-Hydroxybutyric Acid↗
PubMed1997

Calcium release from intracellular stores evoked by extracellular ATP in a Xenopus renal epithelial cell line.

1. The signal transduction mechanism mediating extracellular adenosine 5'-triphosphate (ATP)-induced calcium release in a renal epithelial cell line (A6) was investigated using the whole-cell voltage-clamp technique and fura-2 fluorescence measurement. 2. ATP (10 microM) activated calcium-dependent non-selective cation channels in cells held under voltage clamp. 3. Guanosine 5'-O-(2-thiodiphosphate) (GDP beta S; 0.1-1.0 mM) in the pipette inhibited the ATP-activated calcium-dependent currents. With guanosine 5'-O-(3-thiotriphosphate) (GTP gamma S; 0.1-1.0 mM) in the pipette, the currents were spontaneously elicited without application of ATP. Pretreatment with pertussis toxin (PTX) affected neither the ATP-activated currents nor the increase in intracellular free calcium concentration ([Ca2+]i) evoked by ATP. 4. Intracellular application of neomycin or heparin inhibited the ATP-activated currents. Inositol 1,4,5-trisphosphate (IP3; 0.1-100 microM) in the internal solution produced currents similar to those due to ATP activation. 5. These results suggest that a PTX-insensitive guanosine 5'-triphosphate (GTP)-binding regulatory protein (G. protein) is involved in extracellular. ATP-induced phosphoinositide turnover and subsequent calcium release from IP3-sensitive stores, which subsequently activates the calcium-dependent channels in A6 cells.

Adenosine Triphosphate↗
PubMed1997

Endogenous adenosine facilitates neurotransmission via A2A adenosine receptors in the rat superior colliculus in vivo.

The concentration of endogenous adenosine in the cerebrospinal fluid increased 2-3-fold of the original level in the area of rat superior colliculus after the intraperitoneal administration of an adenosine deaminase inhibitor, EHNA (erythro-9-(2-hydroxy-3-nonyl)adenosine, 10 mg/kg). Potentials evoked in the superior colliculus by optic tract stimulation were also facilitated by 120-160% of their initial amplitudes. A selective A1 adenosine receptor antagonist, DPCPX (8-cyclopentyl-1,3-dipropylxanthine), failed to reduce such EHNA-induced facilitation. However, a selective A2A adenosine receptor antagonist, KF17837 (8(3,4-dimethoxystyryl)-1,3-dipropyl-7-methylxanthine) completely eliminated the facilitatory effects of EHNA. Northern blot analysis demonstrated abundant expression of A1 adenosine receptor mRNA in the superior colliculus. RT-PCR analysis was able to detect the concomitant expression of A2A adenosine receptor mRNA, but at levels lower than one-tenth of the striatal expression. In the superior colliculus, A2A adenosine receptors function predominantly on the facilitatory effects of adenosine, irrespective of the ubiquitous expression of A1 adenosine receptors.

Adenine↗