Search PubMed⌕ Search

Biomedical subjects

H Terada

Publications and source records attributed to H Terada.

At least 37 records · Page 2Linked to original sources
PubMed2001

Growth condition-dependent synchronized changes in transcript levels of type II hexokinase and type 1 glucose transporter in tumor cells.

Transcript levels of hexokinase (HK) isozymes and glucose transporter (GLUT) isoforms in RNA samples of AH130 cells obtained from dish cultures and ascites were evaluated in a quantitative manner. In AH130 cells cultured in dishes, HKI and HKII were expressed at a similar level, but HKIII and HKIV were not. GLUT1 and GLUT3 were also expressed, and messages of these two isoforms represented 27% and 71%, respectively, of the total GLUT messages. A faint signal of GLUT2 was also observed. On the contrary, in cells grown as ascites, the transcript of HKII was dominant, and its level was about 15-fold over that of dish-cultured AH130 cells. Transcript levels of GLUT1 and GLUT3 were 4.5- and 2-fold, respectively, higher than those in dish-cultured cells. Thus, GLUT1 was more susceptible to changes in culture conditions than GLUT3. Based on these results, we concluded that the change in growth conditions caused synchronized changes in the transcript levels of HKII and GLUT1 in AH130 cells. However, such marked changes in the transcript levels of HKII and GLUT1 were not observed when AH130 cells were cultured in dishes under a hypoxic condition, indicating that the observed changes were not solely attributable to the difference in oxygen concentration between the ascites and cell culture conditions. Accordingly, other factors such as growth factors may be responsible for this difference in levels of HKII and GLUT1 between the two growth conditions.

Animals↗
PubMed2001

Endophthalmitis after keratoprosthesis: incidence, bacterial causes, and risk factors.

OBJECTIVES: To determine the rate of endophthalmitis in a group of patients with keratoprostheses and to analyze possible risk factors. METHODS: A total of 108 patient eyes, operated on between 1990 and 2000 with double-plated keratoprostheses, were analyzed with regard to the surface flora, the incidence and cause of bacterial endophthalmitis or sterile vitreitis, the keratoprosthesis design, prophylactic antibiotics, concomitant immunosuppression, and preoperative diagnosis. RESULTS: Surveillance cultures were obtained from 30 uninfected eyes. The flora was similar to that reported in the normal population and did not vary significantly with time. Thirteen cases of bacterial endophthalmitis occurred 2 to 46 months postoperatively in the patient population that had been followed up for 2 months to 17 years (average, 3 years 4 months). The incidence was 39% in 13 patients with Stevens-Johnson syndrome, 19% in 27 patients with ocular cicatricial pemphigoid, and 7% in 28 patients with ocular burns. Only 1 of the other 40 cases (consisting mostly of repeated graft failures in noncicatrizing conditions) developed endophthalmitis; this patient had a filtering bleb. All endophthalmitis pathogens were gram positive: Streptococcus pneumoniae, 23%; other streptococci, 39%; Staphylococcus aureus, 23%; and Staphylococcus epidermidis, 15%. CONCLUSIONS: The most important risk factor for endophthalmitis after these keratoprostheses was found to be preoperative diagnosis. The rate of infection was very high in Stevens-Johnson syndrome and ocular cicatricial pemphigoid, moderate in chemical burns, and low in noncicatrizing corneal disease.

Anti-Bacterial Agents↗
PubMed2001

Simultaneous total arch replacement and abdominal aortic surgery.

It is common to encounter patients with coexisting aortic arch aneurysm and abdominal aortic lesions. We conducted simultaneous total arch replacement and abdominal aortic surgery in 3 patients having such lesions. Mean operative time was 511 minutes and no in-hospital mortality occurred. Postoperative respiratory failure was observed in an 80-year-old patient who recovered and all three patients were discharged in good condition. No other postoperative complication was seen. Simultaneous total arch replacement and abdominal aortic surgery may thus offer advantages to patients with such double aortic lesions if it can be conducted safely.

Aged↗
PubMed2001

New cerebral monitoring using optical topography during total arch replacement.

We investigated the levels of oxygenation in the extended cerebral regions, including the middle cerebral artery region, using optical topography in two patients who underwent total arch replacement assisted by selective cerebral perfusion. During the cooling phase, the oxyhemoglobin levels were almost homogenous. During selective cerebral perfusion, when 18 French and 16 French cannulae were used for the innominate and the left common carotid artery respectively, the oxyhemoglobin levels in the left hemisphere were consistently greater than those in the right. After the 16 French cannula was replaced with a 14 French in the left common carotid artery, then no difference between the hemispheres was found. During the rewarming phase, the increase in the oxyhemoglobin levels in the parietal region was consistently more delayed than that in the temporal region, in both patients. Optical topography might be useful for more precise monitoring of the cerebral circulatory status during an aortic arch operation.

Aorta, Thoracic↗
PubMed2001

Aortic regurgitation with dilation of ascending aorta and right coronary artery occlusion by a rudimentary aortic cusp.

Occlusion of a coronary artery ostium, especially that of the right by an aortic cusp, is a rare congenital anomaly. We had the experience of dealing with an adult patient with aortic regurgitation due to a rudimentary aortic cusp that also occluded the right coronary ostium. We performed composite graft replacement because the patient also had coexistent dilation of the ascending aorta. Postoperative course was uneventful.

Adult↗
PubMed2001

Cerebral oxygenation monitoring for total arch replacement using selective cerebral perfusion.

BACKGROUND: This study was undertaken to verify the safety of our total arch replacement assisted by selective cerebral perfusion with respect to cerebral oxygenation. METHODS: Subjects to be evaluated were selected between February 1999 and March 2000 and comprised 13 patients who underwent total arch replacement (TAR) (TAR group) and 18 patients who had undergone coronary artery bypass grafting or valve replacement (control group). They were monitored throughout the operation by two-channel near-infrared spectroscopy. Changes in intracranial oxyhemoglobin and the tissue oxygenation index were compared between the two groups. Additionally, jugular venous oxygen saturation was simultaneously measured in 10 patients from each group. Maximum changes in these variables from baseline in the TAR group were compared with those in the control group. Bilateral oxygenation differences between two hemispheres were also evaluated. RESULTS: There was no incidence of postoperative cerebral infarction, and no significant difference was observed in the maximum decrease in these variables between the two groups. Bilateral oxygenation differences between the two hemispheres in the TAR group were similar to those in the control group, except for the tissue oxygenation index in the rewarming phase. CONCLUSIONS: From the standpoint of cerebral oxygenation, our technique of total arch replacement was nearly as safe as an ordinary cardiac operation.

Adult↗
PubMed2001

Role of biologic glue repair of proximal aortic dissection in the development of early and midterm redissection of the aortic root.

BACKGROUND: Redissection of the aortic root after supracommissural aortic graft replacement with reapproximation of the layers of the dissected aortic root is relatively rare. Causes and surgical treatment of this lesion remain controversial. METHODS: From January 1983 to September 2000, 130 patients had emergency operation for acute type A aortic dissection. Of them, 57 patients underwent root reconstruction using biologic glues and 4 patients (7.0%) developed redissection of the aortic root associated with moderate to severe aortic regurgitation 5 to 27 months after the initial operation. In all patients, the proximal false lumen was obliterated with infusion of gelatin-resorcinol-formaldehyde (GRF) glue or BioGlue and the aorta was reinforced with Teflon felt strip or Surgicel placed on its outside wall. RESULTS: During reoperation, the noncoronary aortic sinus was found to be redissected in all patients with the dissection extending retrogradely to the aortic annulus. This resulted in aortic regurgitation with prolapse of the noncoronary cusp because the proximal suture line dehisced. Histopathology showed disappearance of the nuclei of the medial smooth muscle cells, suggesting tissue necrosis at the site of GRF glue application. The lesions were treated successfully with full root replacement using a freestyle heterograft bioprosthesis or a composite graft prosthesis. CONCLUSIONS: The use of biologic glues for reapproximating the layers of the dissected aortic root is associated with a certain amount of risk of aortic wall necrosis. Therefore, care should be taken to ensure proper use of these glues. Full root replacement could be a preferable technique for treating redissection of the aortic root.

Adult↗
PubMed2001

Molecular characteristics of astaxanthin and beta-carotene in the phospholipid monolayer and their distributions in the phospholipid bilayer.

The molecular characteristics of the monolayers of astaxanthin with polar group on the beta-ionone ring in the molecule and beta-carotene without polar group and their interactions in mixed carotenoid-phospholipid monolayers and the effects of carotenoids on the phase behavior of the phospholipid bilayers were examined by the monolayer technique and differential scanning calorimetry (DSC). We found from the monolayer study that beta-carotene had an amphiphilic nature. The molecular assembly of astaxanthin in the monolayer at the hydrophobic/hydrophilic interface was more stable than that of beta-carotene. Dimyristoylphosphatidylcholine (DMPC) in the monolayer was miscible with astaxanthin in the range of 0-0.4 mol fractions of astaxanthin, but not fully miscible with beta-carotene even at low concentrations below 0.1 mol fraction of beta-carotene. Surface potential and compression/expansion cycles of beta-carotene monolayer indicated the formation of molecular aggregates by itself. DSC study showed that when small amount of astaxanthin was added, the transition temperature of dipalmitoylphosphatidylcholine (DPPC) was markedly shifted to lower temperatures and that the transition peak was asymmetrically broadened, indicative of a significant depression in cooperativity of the gel to liquid-crystalline transition. The asymmetric DSC endothermic bands of DPPC incorporating small amounts of astaxanthin were well fit by deconvolution into two to three domains containing different concentrations of astaxanthin. On the contrary, the incorporation of beta-carotene resulted in a small depression of the main transition temperature with a slight broadening of the transition peak, suggesting a small miscibility of beta-carotene with the phospholipid bilayer or a formation of aggregates of beta-carotene in the membranes. These results suggest that there would be a high localized concentration in the phase separated membrane for astaxanthin or beta-carotene to function effectively as scavenger.

1,2-Dipalmitoylphosphatidylcholine↗
PubMed2001

The importance of glycolytically-derived ATP for the Na+/H+ exchange activity in guinea pig ventricular myocytes.

The cardiac subtype of Na+/H+ exchanger (NHE-1) plays an important role in the regulation of intracellular pH (pHi) and also can be a major route for Na+ influx. Although intracellular ATP is required for the optimal function of NHE-1, the regulation of the exchanger by ATP is less well characterized. This study was designed to investigate which intracellular ATP generated by oxidative phosphorylation or by glycolysis is dominant for the activation of NHE-1 in intact cardiac myocytes. Isolated guinea pig ventricular myocytes were loaded with the pHi-sensitive fluorescent indicator, 2'-7'-bis(carboxyl)-5',6'-carboxy fluorescein (BCECF), and exposed to 20 mM 2-deoxyglucose (2-DG) or 2 mM sodium cyanide (CN) to inhibit glycolysis or oxidative phosphorylation, respectively. The activity of NHE-1 was estimated with pHi recovery following transient application of 15 mM NH4Cl (NH4Cl prepulse). After the NH4Cl prepulse, pHi decreased from 7.00 +/- 0.03 (mean +/- S.E.) to 6.60 +/- 0.06 and recovered to 6.94 +/- 0.13 at 10 min (n = 7). The pHi recovery was suppressed in the presence of 2-DG (6.67 +/- 0.05, p < 0.01, n = 7), but was not changed in the presence of CN (6.88 +/- 0.18, n = 6). Since there was no difference in the intrinsic H+ buffering power, the estimation of the net acid efflux demonstrated that the activity of NHE-1 was significantly depressed in 2-DG. The inhibitory effect of 2-DG was not due to more extensive depletion of global intracellular ATP or secondary to the change in either intracellular Na+ or Ca2+ concentration. We concluded that ATP generated by glycolysis rather than by oxidative phosphorylation is essential to activate NHE-1 in ventricular myocytes.

Adenosine Triphosphate↗
PubMed2001

Improved results of atherosclerotic arch aneurysm operations with a refined technique.

OBJECTIVE: We sought to analyze the postoperative hospital mortality and postoperative neurologic dysfunction in patients who had total arch replacement for atherosclerotic arch aneurysms using our recent refined technique. METHODS: Between June 1997 and April 2000, 50 consecutive patients underwent total arch replacement with an aortic arch branched graft for atherosclerotic arch aneurysms. Their mean age was 71 +/- 7 years (range, 57-87 years). Forty-eight (96%) patients were operated on electively, and the remaining 2 (4%) were operated on an emergency basis because of rupture of aneurysm. All operations were performed with hypothermic extracorporeal circulation, selective cerebral perfusion for cerebral protection during aortic arch repair, and systemic circulatory arrest during distal graft anastomosis. A total of 19 concomitant procedures were done in 17 patients. Mean selective cerebral perfusion time was 78.1 +/- 16.5 minutes. RESULTS: Overall in-hospital mortality was 2% (95% confidence intervals, 0%-5.9%). On univariable analysis, permanent neurologic dysfunction was the only risk factor for in-hospital mortality. Postoperative temporary and permanent neurologic dysfunctions were 4% (95% confidence intervals, 0%-9.4%) and 4% (95% confidence intervals, 0%-9.4%), respectively. On univariable analysis, cardiopulmonary bypass time was the only risk factor for temporary neurologic dysfunction, and history of cerebrovascular disease was the only risk factor for permanent neurologic dysfunction. There was no significant correlation between selective cerebral perfusion time and temporary and permanent neurologic dysfunction. CONCLUSION: Integrated cerebral protective effect of antegrade selective cerebral perfusion and total arch replacement with an aortic arch branched graft could substantially reduce in-hospital mortality and postoperative neurologic dysfunction in patients with atherosclerotic arch aneurysms.

Aged↗
PubMed2001

Experimental study on the effect of antegrade cerebral perfusion on brains with old cerebral infarction.

OBJECTIVE: Patients with old cerebral infarction who undergo aortic arch operations are susceptible to postoperative neurologic dysfunction. To verify such susceptibility, we performed this experimental study. METHODS: A cerebral infarct model was created in mongrel dogs by means of injection of cylindrical silicone embolus through the internal carotid artery. The dogs that had obvious neurologic deficits 1 day later and survived for 4 weeks or more were included in the cerebral infarct model. One month after cerebral infarction was induced, deep hypothermia and selective cerebral perfusion were used in 14 mongrel dogs (infarct group, n = 7; control group, n = 7). During this procedure, serum glutamate concentration and venous-arterial lactate difference were measured. Histopathologic study of the brain was also performed. RESULTS: Changes in venous-arterial lactate difference in both groups were almost similar, except in the rewarming phase. At 32 degrees C during rewarming, the venous-arterial lactate difference in the infarct group was significantly higher than that in the control group (P =.006). Although pre-cooling concentrations of serum glutamate were similar in both groups, the values in the infarct group at the end of rewarming were significantly higher than those in the control group (P =.046). On histologic examination, the presence of old cerebral infarction with gliosis was confirmed in the infarct group, but neither new cerebral infarction nor destruction of the blood-brain barrier was found. CONCLUSION: We observed an accelerated anaerobic metabolism and an increased extracellular glutamate release in the infarct group. The brain with old cerebral infarction is more susceptible to ischemia during arch operation than noninfarcted brain.

Animals↗
PubMed2001

Reduction of ischemic spinal cord injury by dextrorphan: comparison of several methods of administration.

OBJECTIVES: We investigated the effect of dextrorphan, an N -methyl-D -aspartate receptor antagonist, on the reduction of ischemic spinal cord injury and the safe clamping time after various methods of administration. METHODS: Spinal cord ischemia was induced in New Zealand White rabbits by infrarenal aortic clamping and animals were divided into 5 groups. Group A (n = 15) received simple clamping. Groups B (n = 20) and C (n = 35) received dextrorphan pretreatment (10 mg/kg), followed by continuous intravenous or intra-aortic infusion (1 mg/min), respectively. Group D (n = 25) received the same dextrorphan pretreatment and bolus intra-aortic injection at clamping (1 mg per minute of clamping time). Group E (n = 15) received bolus intrathecal injection of dextrorphan (0.2 mg/kg). Each dextrorphan-treated group had a small group of control animals (n = 5). The neurologic status was assessed by the Johnson score (5 = normal, 0 = paraplegic) 48 hours after unclamping, and animals were put to death for histopathologic examination. RESULTS: All dextrorphan-treated groups showed better neurologic function than the respective control animals (P <.001 vs groups B, C, and D; P =.014 vs group E). The order of efficacy of dextrorphan (as revealed by the average of neurologic status) was as follows: group C > group D (P =.017, after 50 minutes of clamping), group D > group B (P =.014, after 45 minutes of clamping), and group B > group E (P <.001, after 40 minutes of clamping). Histopathologic findings did not necessarily correspond with hind-limb neurologic function. CONCLUSIONS: Dextrorphan reduced the physical findings associated with ischemic spinal cord injury, and continuous intra-aortic infusion prolonged the safe clamping time significantly more than delivery by other routes.

Animals↗
PubMed2001

The Japan Home-health Apparatus Industrial Association: investigation of home-use electronic sphygmomanometers.

The Japanese Home-health Apparatus Industrial Association is an official independent organization comprising ten departments. That concerned with home electronic sphygmomanometers, which has seven participants from different Japanese manufacturers, has already undertaken and is currently involved in various activities related to voluntary standards for performance validation and quality assurance. Because Japanese companies form a large proportion of manufacturers, these activities are important in terms of autonomic regulation. Although many improvements have been made to home electronic sphygmomanometers, some problems still remain unresolved, especially in terms of measurement reliability and easy operation by lay people. Another aspect of the department's work relates to making proposals on major validation standards, such as those of the Association for the Advancement of Medical Instrumentation, the British Hypertension Society and Comité Européen de Normalisation (CEN). Clinical validation should be discussed in order to define a more accurate standard method of measurement using auscultation and more appropriate criteria that are unaffected by primary blood pressure variation.

Blood Pressure Determination↗
PubMed2001

Significant expression of functional human type 1 mitochondrial ADP/ATP carrier in yeast mitochondria.

As a first step to characterize the unknown functional properties of the human mitochondrial ADP/ATP carrier (AAC), we tried to express human type 1 AAC (hAAC1) in Saccharomyces cerevisiae. Expression of hAAC1 in yeast mitochondrial membrane was very low, although its transcript level was high. Its expression was improved greatly by replacement of its N-terminal region with the corresponding region of yeast type 2 AAC (yAAC2), as observed with the bovine type 1 AAC (bAAC1). This chimeric hAAC1 showed similar ADP transport activity to that of chimeric bAAC1, corresponding to the transport activity of bAAC1 in bovine heart mitochondria. These results suggested that the N-terminal region of yAAC2 is important for expression of the mammalian carriers in yeast mitochondria. Using the present expression system, studies on the functional properties of the human AAC isoforms in relation to their structures are now possible.

Animals↗
PubMed2001

[True posterior communicating artery aneurysm].

We report a case of a true posterior communicating artery aneurysm. A 51-year-old male suffered a subarachnoid hemorrhage with severe headache and vomiting. A true posterior communicating artery aneurysm was recognized after repeated angiography on the seventh day. Right frontotemporal craniotomy was performed and the aneurysm was successfully clipped. The incidence of true posterior communicating artery aneurysms ranges from 0.1-2.8%, and 21 cases including our case have been reported in detail. There are no reported cases in which the aneurysm arises from the branching site of perforating arteries. In almost all cases the dome of the aneurysm projects inferiorly or posteriorly or laterally, so perforating arteries from the posterior communicating artery rarely interfere with dissection of the aneurysm or neck clipping. In a few cases, true posterior communicating artery aneurysms had been diagnosed as IC-PC aneurysms preoperatively, leading to intraoperative aneurysmal rupture or postoperative neurological deficit or death. In the cases of a fusiform aneurysm or an aneurysm of wide-based neck, there may be no other choice than trapping of the aneurysm. It is difficult to predict whether trapping causes postoperative ischemic complications.

Cerebral Angiography↗
PubMed2001

Importance of glycolytically derived ATP for Na+ loading via Na+/H+ exchange during metabolic inhibition in guinea pig ventricular myocytes.

The increase in the intracellular Na+ concentration ([Na+](i)) during myocardial ischaemia is crucial for ischaemia/reperfusion cell injury, and the cardiac subtype of the Na+/H+ exchanger (NHE-1) has been shown to be a major pathway for Na(+) loading. While the importance of glycolytically derived ATP for the optimal functioning of membrane transporters and channels has been suggested, whether NHE-1 is actually activated during myocardial ischaemia remains controversial. Here we examined whether the activity of NHE-1 is predominantly dependent on intracellular ATP generated by glycolysis, and whether the additional inhibition of glycolysis can affect the increase in ([Na+](i)) during the inhibition of oxidative phosphorylation in intact guinea pig ventricular myocytes. The selective inhibition of glycolysis by 2-deoxyglucose prevented the recovery of intracellular pH and the transient increase in ([Na+](i)) following intracellular acidosis induced by a NH(4)Cl pre-pulse. During severe metabolic inhibition (SMI; induced by amobarbital and carbonyl cyanide m-chlorophenylhydrazone in a glucose-free perfusate), most myocytes changed from rod-shaped to contracted forms by approximately 15 min. ([Na+](i)) increased linearly until rigor contracture occurred, but after rigor contracture the rate of increase was blunted. The increase in ([Na+](i)) during SMI was suppressed significantly by an inhibitor of NHE-1, hexamethylene amiloride. The increase in the intracellular Mg(2+) concentration, which can reciprocally indicate depletion of intracellular ATP, was small during the initial 10 min of SMI, but became larger from just a few minutes before rigor contracture. In the presence of 2-deoxyglucose, the time to rigor during SMI was shortened, but the increase in ([Na+](i)) before rigor contracture was not significant, and was much less than that in the absence of 2-deoxyglucose. It is concluded that ATP generated by glycolysis is essential to activate NHE-1, and that the dependence of NHE-1 on glycolysis might affect the increase in ([Na+](i)) observed during myocardial ischaemia.

Adenosine Triphosphate↗
PubMed2000

Specific labeling of the bovine heart mitochondrial phosphate carrier with fluorescein 5-isothiocyanate: roles of Lys185 and putative adenine nucleotide recognition site in phosphate transport.

The amine/SH-modifying fluorescein 5-isothiocyanate (FITC) specifically labeled Lys(185) in the putative membrane-spanning region of the phosphate carrier from both the cytosolic and matrix sides of bovine heart mitochondria at 0 degrees C and pH 7.2, and the labeling inhibited the phosphate transport. Nonmodifying fluorescein derivatives having similar structural features to those of ADP and ATP (Majima, E., Yamaguchi, N., Chuman, H., Shinohara, Y., Ishida, M., Goto, S., and Terada, H. (1998) Biochemistry 37, 424-432) inhibited the specific FITC labeling and phosphate transport, but the nonfluorescein phenylisothiocyanate did not inhibit FITC labeling, suggesting that there is a region recognizing the adenine nucleotides in the phosphate carrier and that this region is closely associated with the transport activity. The phosphate transport inhibitor pyridoxal 5'-phosphate inhibited the specific FITC labeling, possibly due to competitive modification of Lys(185). In addition, FITC inhibited the ADP transport and specific labeling of the ADP/ATP carrier with the fluorescein SH reagent eosin 5-maleimide. Based on these results, we discuss the structural features of the phosphate carrier in relation to its transport activity.

Adenosine Diphosphate↗