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Biomedical subjects

T Ueda

Publications and source records attributed to T Ueda.

At least 307 records · Page 17Linked to original sources
PubMed1999

The Arabidopsis thaliana RER1 gene family: its potential role in the endoplasmic reticulum localization of membrane proteins.

Many endoplasmic reticulum (ER) proteins are known to be localized to the ER by a mechanism called retrieval, which returns the molecules that are exported from the ER to the Golgi apparatus back to the ER. Signals are required to be recognized by this retrieval system. In the work on yeast Saccharomyces cerevisiae, we have demonstrated that transmembrane domains of a subset of ER membrane proteins including Sec12p, Sec71p and Sec63p contain novel ER retrieval signals. For the retrieval of these proteins, a Golgi membrane protein, Rer1p, is essential (Sato et al., Mol. Biol. Cell 6 (1995) 1459-1477; Proc. Natl. Acad. Sci. USA 94 (1997) 9693-9698). To address the role of Rer1p in higher eukaryotes, we searched for homologues of yeast RER1 from Arabidopsis thaliana. We identified three cDNAs encoding Arabidopsis counterparts of Rer1p with an amino acid sequence identity of 39-46% to yeast Rer1p and named AtRER1A, AtRER1B, and AtRER1C1. AtRer1Ap and AtRer1Bp are homologous to each other (85% identity), whereas AtRer1C1p is less similar to AtRer1Ap and AtRer1Bp (about 50%). Genomic DNA gel blot analysis indicates that there are several other AtRER1-related genes, implying that Arabidopsis RER1 constitutes a large gene family. The expression of these three AtRER1 genes is ubiquitous in various tissues but is significantly higher in roots, floral buds and a suspension culture in which secretory activity is probably high. All the three AtRER1 cDNAs complement the yeast rer1 mutant and remedy the defect of Sec12p mislocalization. However, the degree of complementation differs among the three with that of AtRER1C1 being the lowest, again suggesting a divergent role of AtRer1C1p.

Amino Acid Sequence↗
PubMed1999

Randomized clinical trial of ultrasonic dissector or conventional division in distal pancreatectomy for non-fibrotic pancreas.

BACKGROUND: Resection of the non-fibrotic pancreas is prone to postoperative pancreatic fistula because of well preserved exocrine secretions and easily crushed soft parenchyma. The purpose of this study was to evaluate ultrasonic dissection for division of the non-fibrotic pancreas in distal pancreatectomy. METHODS: All pancreata included in this study were soft on direct palpation and their main ducts had no dilatation, at least proximally from the transection line. Fifty-eight patients with gastric cancer or pancreatic disease were randomly assigned to the two groups. In the ultrasonic dissection (UD) group (n = 27), all pancreatic ducts were identified and ligated securely. The stump was left open without parenchymal suturing. In the conventional (CV) group (n = 31), the pancreas was cut with a knife and the stump was oversewn in mattress fashion. The main pancreatic duct was ligated in all patients in both groups. Pancreatic fistula was defined as a pancreatic fluid discharge for more than 7 days after operation diagnosed according to amylase concentration in the drainage fluid. RESULTS: In the UD group, approximately 20-30 tubes including a mean(s.d.) 5.2(0.8) (range 4-6) pancreatic ducts were skeletonized and ligated per patient. There were nine pancreatic fistulas (16 per cent); one in the UD group and eight in the CV group (P = 0.020). CONCLUSION: In distal pancreatectomy for the non-fibrotic pancreas, ultrasonic dissection without suture closure of the stump reduced the incidence of pancreatic fistula compared with conventional division and suture, in this randomized trial.

Adult↗
PubMed1999

Spatio-temporally regulated expression of receptor tyrosine kinases, mRor1, mRor2, during mouse development: implications in development and function of the nervous system.

BACKGROUND: Drosophila neurospecific receptor tyrosine kinases (RTKs), Dror and Dnrk, as well as Ror1 and Ror2 RTKs, isolated from human neuroblastoma, have been identified as a structurally related novel family of RTKs (Ror-family RTKs). Thus far, little is known about the expression and function of mammalian Ror-family RTKs. RESULTS: We have identified murine Ror-family RTKs, mRor1 and mRor2. Both mRor1 and mRor2 genes are induced upon neuronal differentiation of P19EC cells. During neuronal differentiation in vitro, the expression of mRor2 is transiently induced, although that of mRor1 increases continuously. During embryogenesis, the mRor1 gene is expressed in the developing nervous system within restricted regions and in the developing lens epithelium. The expression of mRor1 is sustained in the nervous system and is also detected in non-neuronal tissues after birth. In contrast, the expression of mRor2 is detected mainly in the developing nervous system within broader regions and declines after birth. Possible relationships of mRor1 and mRor2 genes with previously identified mutants have also been examined. CONCLUSIONS: The developmental expressions of mRor1 and mRor2, in particular in the nervous system, are differentially regulated, reflecting their expression patterns in vitro. mRor1 and mRor2 may thus play differential roles during the development of the nervous system.

Amino Acid Sequence↗
PubMed1999

Orthotopic ileal neobladder in male patients: functional outcomes of 66 cases.

BACKGROUND: Orthotopic urinary diversion has become the preferred form of bladder reconstruction after cystectomy. We report on our experience with 66 male patients undergoing this procedure from November 1990 to February 1998. METHODS: A neobladder was constructed using an ileal segment with a Hautmann type bladder. Complications were assessed and subdivided into early and late types. Voiding function was evaluated in terms of voiding pattern and continence. Median follow up was 19.5 (range 3.5-87.7) months. RESULTS: There was one (1.5%) perioperative death. The most frequent pouch-related and unrelated early complications were persistent urine leak (7.6%) and prolonged ileus (16.7%), respectively, the majority of cases of which were managed conservatively. Analysis of late complications revealed 6.2% ureteroileal stenosis and 1.5% urethrointestinal stenosis rates, but no case of bladder stone formation. Of the 61 patients in whom voiding function was evaluable, 95.1% achieved excellent daytime continence, while only 67.2% had night-time continence. With regard to posture at voiding, 23 (37.7%) voided in a sitting position. Three of the patients (4.9%) were unable to void and required regular intermittent catheterization. CONCLUSIONS: An orthotopic neobladder can be constructed with acceptable morbidity and excellent functional results. We believe that orthotopic urinary diversion offers an attractive alternative to a bladder substitute when cystectomy is required.

Adult↗
PubMed1999

Metanephric adenoma of the kidney.

BACKGROUND: Metanephric adenoma is a rare renal neoplasm that is histologically and clinically unique. We found this neoplasm in a 62-year-old female, whose renal tumor was incidentally detected on abdominal ultrasound examination. METHODS/RESULTS: Ultrasound, computed tomography and magnetic resonance imaging were compatible with those of renal cell carcinoma. With a diagnosis of renal cell carcinoma, right partial nephrectomy was performed. This tumor showed histologic similarity to developing metanephric tubular epithelium. It was composed of uniformly small epithelial cells, which formed tubules. CONCLUSIONS: The patient has been well and healthy for 20 months after surgery. The unique features of metanephric adenoma should be clinically and pathologically recognized because of its invariably benign course.

Adenoma↗
PubMed1999

Takayasu's aortitis with dissection in systemic lupus erythematosus.

A forty-seven-year-old Japanese woman under treatment for systemic lupus erythematosus (SLE), complained of severe back pain. Chest X-ray and MRI showed an aneurysmal dilatation of the ascending aorta. Subsequently an aortic replacement was performed. Microscopically, the resected aorta showed Takayasu's aortitis with chronic dissection. Both aortitis and dissection are rare events in SLE patients. To our knowledge, this is the first report of Takayasu's aortitis with dissection in a patient with SLE.

Aortic Dissection↗
PubMed1999

Complete DNA sequence of the mitochondrial genome of the ascidian Halocynthia roretzi (Chordata, Urochordata).

The complete nucleotide sequence of the 14,771-bp-long mitochondrial (mt) DNA of a urochordate (Chordata)-the ascidian Halocynthia roretzi-was determined. All the Halocynthia mt-genes were found to be located on a single strand, which is rich in T and G rather than in A and C. Like nematode and Mytilus edulis mtDNAs, that of Halocynthia encodes no ATP synthetase subunit 8 gene. However, it does encode an additional tRNA gene for glycine (anticodon TCT) that enables Halocynthia mitochondria to use AGA and AGG codons for glycine. The mtDNA carries an unusual tRNA(Met) gene with a TAT anticodon instead of the usual tRNA(Met)(CAT) gene. As in other metazoan mtDNAs, there is not any long noncoding region. The gene order of Halocynthia mtDNA is completely different from that of vertebrate mtDNAs except for tRNA(His)-tRNA(Ser)(GCU), suggesting that evolutionary change in the mt-gene structure is much accelerated in the urochordate line compared with that in vertebrates. The amino acid sequences of Halocynthia mt-proteins deduced from their gene sequences are quite different from those in other metazoans, indicating that the substitution rate in Halocynthia mt-protein genes is also accelerated.

Animals↗
PubMed1999

Nucleotide sequences of animal mitochondrial tRNAs(Met) possibly recognizing both AUG and AUA codons.

To elucidate the role of modified nucleosides of tRNA in mitochondrial translation systems, especially with regard to their codon recognition, we purified mitochondrial tRNAs(Met) isolated from liver of frog, chicken and rat, and determined their nucleotide sequences. All of these tRNAs(Met) were found to possess 5-formylcytidine in the first letter of the anticodon, which is known to be prerequisite for bovine mt tRNA(Met) to decode AUA codon as well as AUG codon. These tRNA possesses two pseudeuridines in similar positions, and only chicken tRNA(Met) had ribothymidine at the first position of the T-loop, which is always found in the usual tRNAs. Considering that AUA codon is used as five times frequently as AUG codon in these animal mitochondrial genomes, it is deduced that 5-formylcytidine at the wobble position is essential for the recognition of both AUA and AUG codons.

Animals↗
PubMed1999

The molecular weight ratio of monomethoxypolyethylene glycol (mPEG) to protein determines the immunotolerogenicity of mPEG proteins.

Immunotolerogenic activity of monomethoxypolyethylene glycol- (mPEG) conjugated proteins is a beneficial property in protein pharmaceutics. However, procedures for the preparation of tolerogenic mPEG proteins have not yet been defined. We prepared mPEG proteins with different mPEG contents using three proteins, hen egg lysozyme, ovalbumin and bovine gamma globulin, and their tolerogenicities to antigen-specific T and B cell responses were examined. We found the most appropriate ratio of tolerance induction to be 1.5-2.0, which is the molecular weight ratio of conjugated total mPEGs to protein. This value may assist in the preparation of tolerogenic mPEG proteins.

Animals↗
PubMed1999

Outcome in acute stroke with successful intra-arterial thrombolysis and predictive value of initial single-photon emission-computed tomography.

This study investigates retrospectively, in selected patients, the ischemic outcome (reversible ischemia, infarction, and hemorrhage) and neurologic outcome of acute stroke treated with intra-arterial thrombolysis and the predictive value of pretreatment single-photon emission-computed tomography (SPECT). Thirty patients with complete recanalization within 12 hours were analyzed. The extent of ischemia was outlined on SPECT, and two CBF parameters were calculated: the ratio of ischemic regional activity to CBF in the cerebellum and the asymmetry index. Reversible ischemia, infarction, and hemorrhage were identified by comparing SPECT and follow-up computed tomography. Nine patients (30%) had no or small infarction, 14 (47%) had medium or large infarction, and seven (23%) had hemorrhage. Forty-two lesions were identified (22 reversible ischemia, 13 infarction, and 7 hemorrhage). Duration of ischemia, urokinase dose, disease type, and occlusion site were nonsignificant factors, whereas neurologic outcome and CBF parameters were significant among the three patient groups and three types of ischemic lesions. Ischemic tissue with CBF greater than 55% of cerebellar flow still may be salvageable, even with treatment initiated 6 hours after onset of symptoms. Ischemic tissue with CBF greater than 35% of cerebellar flow still may be salvageable with early treatment (less than 5 hours). Ischemic tissue with with CBF less than 35% of cerebellar flow may be at risk for hemorrhage within the critical time window. Pretreatment SPECT can provide useful parameters to increase the efficacy of thrombolysis by reducing hemorrhagic complications and improving neurologic outcome.

Adult↗
PubMed1999

Current and future imaging of acute cerebral ischemia: assessment of tissue viability by perfusion imaging.

With the advances and availability of new imaging modalities, the role of imaging of acute stroke has been broadened from making diagnosis to providing valuable information for patient management. We need to have rapid diagnostic modalities that distinguish reversible ischemic tissue from irreversibly damaged tissue for successful thrombolytic therapy. Although diffusion imaging has been reported to have both high sensitivity and specificity for acute ischemia in clinical studies, previous reports do not conclude whether the diffusion abnormality is indicative of reversibly or irreversibly injured tissue. Perfusion imaging such as perfusion magnetic resonance imaging and single-photon emission computed tomography may have the potential for providing useful information that determines tissue viability and/or reversibility. Cerebral blood flow thresholds evaluated by pretreatment single-photon emission computed tomography provide important information that is potentially useful in the management of acute stroke patients with intra-arterial thrombolysis. Perfusion imaging, when combined with diffusion imaging, may thus be potentially useful in improving patient selection for thrombolytic therapy.

Acute Disease↗
PubMed1999

Influence of treated blood pressure on progression of silent cerebral infarction.

PURPOSE AND METHODS: To examine whether treatment for hypertensive patients prevents the progression of cerebral infarction, we performed magnetic resonance imaging (MRI) repeatedly at mean intervals of 22 months on 117 Japanese subjects aged 65-89 (mean 74 years), including 84 hypertensive patients. The patients were given various anti-hypertensive agents, and the blood pressure of each patient was monitored periodically during the observation period. Depending on the average blood pressure at the end of the follow-up period, hypertensive patients were classified into three subgroups: normotension (N), borderline (B) and hypertension (H). None had a prior history of symptomatic cerebral infarction and neurological abnormalities. The number of infarcted lesions were determined on brain MRI by two independent observers. RESULTS: Silent cerebral infarction (SCI) lesions were observed in 42 hypertensive subjects (50.0%) and in eight control subjects (24.2%) on enrollment. The numbers of SCI lesions increased in 33 hypertensive subjects (39.3%) and three control subjects (9.1%) during the observation period. In the hypertensive subjects, an increased number of infarcted lesions was found in six of 28 subjects in group N (21.4%), 17 of 44 in group B (38.6%), and 10 of 12 in group H (83.3%). Thus, blood pressure controlled to the normal level appears to result in a lower incidence of progression of infarcted areas in patients with hypertension (N versus H, P < 0.001). CONCLUSION: Our data indicate that an appropriate anti-hypertensive treatment reduces the risk of a cerebrovascular accident in hypertensive patients.

Aged↗
PubMed1999

Norepinephrine, but not epinephrine, enhances platelet reactivity and coagulation after exercise in humans.

The effects of exercise and catecholamines on platelet reactivity or coagulation and fibrinolysis appear to be inconsistent. This may be partly due to the methods employed in previous studies. In the present study, we investigated the effects of acute aerobic exercise and catecholamines on the thrombotic status by a novel in vitro method, shear-induced hemostatic plug formation (hemostatometry), using nonanticoagulated (native) blood. Aerobic exercise (60% maximal O2 consumption) was performed by healthy male volunteers for 20 min, and the effect on platelet reactivity and coagulation was assessed by performing hemostatometry before and immediately after exercise. Exercise significantly increased shear-induced platelet reactivity, coagulation, and catecholamine levels. The effect of catecholamines on platelet reactivity and coagulation was assessed in vitro by adding catecholamines to blood collected in the resting state. The main findings of the present study are that elevation of circulating norepinephrine at levels that are attained during exercise causes platelet hyperreactivity and a platelet-mediated enhanced coagulation. This may be a mechanism of an association of aerobic exercise with thrombotic risk.

Adult↗
PubMed1999

In vitro testing of antioxidants and biochemical end-points in bovine retinal tissue.

Lipid peroxidation in aliquots of bovine retina (without rod outer segments, ROS), purified ROS and retinal pigment epithelium (RPE) was initiated with 5 mM ferric iron and 80 mM ADP. After 30 min of oxidation at 37 degrees C, the concentration of thiobarbituric-acid-reacting substances (TBARS) which approximates lipid hydroperoxide (LHP), increased in the ROS from 2.0 +/- 3.6 to 90.2 +/- 34.5 nmol malondialdehyde (MDA)/mg protein and in the RPE from 0.54 +/- 0.2 to 51.5 +/- 15.8 nmol MDA/mg protein. Sixteen lipid and aqueous antioxidants (AOX) from natural or synthetic sources, including five flavonoids, were evaluated for their ability to inhibit the oxidative reaction. Palm-oil-derived vitamin E showed significant protection in retina, ROS and RPE (64, 68 and 74%), respectively. Of the flavonoids tested, good protection in the retina was found at 10(-5) M for epigallocatechin gallate (50%) and at 50 ng/ml for pycnogenol (61%) and catechin (52%). When catechin and palm oil vitamin E, catechin and coenzyme Q(10) or coenzyme Q(10) and pycnogenol were combined, the individual effect was enhanced. TBARS as an indirect measure of LHP level and hemoglobin-methylene blue determination for direct LHP were used as alternative end-point determinations of lipid peroxidation. These measure different aspects of AOX reactions. The results demonstrate the usefulness of an in vitro model system that can rapidly and accurately determine the capacity of a single AOX against lipid peroxidation or be used to show synergistic efficacy.

Animals↗
PubMed1999

Daily aerobic exercise improves reactive hyperemia in patients with essential hypertension.

The effects of long-term aerobic exercise on endothelial function in patients with essential hypertension remain unclear. To determine whether endothelial function relating to forearm hemodynamics in these patients differs from normotensive subjects and whether endothelial function can be modified by continued physical exercise, we randomized patients with essential hypertension into a group that engaged in 30 minutes of brisk walking 5 to 7 times weekly for 12 weeks (n=20) or a group that underwent no activity modifications (control group, n=7). Forearm blood flow was measured using strain-gauge plethysmography during reactive hyperemia to test for endothelium-dependent vasodilation and after sublingual nitroglycerin administration to test endothelium-independent vasodilation. Forearm blood flow in hypertensive patients during reactive hyperemia was significantly less than that in normotensive subjects (n=17). Increases in forearm blood flow after nitroglycerin were similar between hypertensive and normotensive subjects. Exercise lowered mean blood pressure from 115.7+/-5.3 to 110.2+/-5.1 mm Hg (P<0.01) and forearm vascular resistance from 25.6+/-3.2 to 23. 2+/-2.8 mm Hg/mL per minute per 100 mL tissue (P<0.01); no change occurred in controls. Basal forearm blood flow, body weight, and heart rate did not differ with exercise. After 12 weeks of exercise, maximal forearm blood flow response during reactive hyperemia increased significantly, from 38.4+/-4.6 to 47.1+/-4.9 mL/min per 100 mL tissue (P<0.05); this increase was not seen in controls. Changes in forearm blood flow after sublingual nitroglycerin administration were similar before and after 12 weeks of exercise. Intra-arterial infusion of the nitric oxide synthase inhibitor NG-monomethyl-L-arginine abolished the enhancement of reactive hyperemia induced by 12 weeks of exercise. These findings suggest that through increased release of nitric oxide, continued physical exercise alleviates impairment of reactive hyperemia in patients with essential hypertension.

Analysis of Variance↗
PubMed1999

Multivariable analysis of predictive factors related to outcome at 6 months after intra-arterial thrombolysis for acute ischemic stroke.

BACKGROUND AND PURPOSE: Recent reports have suggested that a rapid assessment of pretreatment residual cerebral blood flow (CBF) could be used to optimize selection criteria for thrombolysis in patients with acute ischemic stroke to improve clinical outcome. We investigated retrospectively residual CBF and other clinical factors related to outcome at 6 months after intra-arterial thrombolysis by using multivariable analysis. METHODS: Seventy-six patients received intra-arterial thrombolysis within 6 hours of symptom onset. The multiple regression method was used to analyze associations between the modified Rankin scale (MRS) at 6 months after treatment and clinical factors including age, infarction type, duration of ischemia, dose of urokinase, degree of recanalization, hemorrhage, National Institutes of Health Stroke Scale score (NIHSSS), and residual CBF evaluated by pretreatment single-photon emission-computed tomography; these values were assessed with the use of the regional-to-cerebellar activity (R/CE) ratio of ischemic region to cerebellum and asymmetry index. RESULTS: MRS at 6 months was good (0 to 3) in 65% and poor (4 to 6) in 35%. Factors significantly related to MRS at 6 months were R/CE ratio (P<0.0001), NIHSSS at baseline and the following day (P<0.0001), cardioembolic infarction (P=0.0014), age (P=0.0074), and recanalization grade (P=0. 007). NIHSSS of >20, R/CE ratio of <0.35, cardioembolic infarction, incomplete recanalization (grade <3), and older age (>75 years) were determined to be significant independent predictors of poor outcome. CONCLUSIONS: The residual CBF, neurological score at baseline and the following day, age, and recanalization grade correlated significantly with long-term outcome. The NIHSSS of >20 and R/CE ratio of <0.35 were determined to be significant independent predictors of poor outcome by multivariable analysis.

Acute Disease↗