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Biomedical subjects

T Ueda

Publications and source records attributed to T Ueda.

At least 1,009 records · Page 56Linked to original sources
PubMed1991

Recurrence of bladder tumors following surgery for transitional cell carcinoma of the upper urinary tract.

A retrospective analysis of 53 patients with an upper urinary tract (UUT) transitional cell carcinoma, which was treated surgically, was performed in relation to the development of a subsequent bladder tumor. In 19 of the 53 patients (35.8%) bladder tumors developed following surgery of a UUT tumor. The simultaneous occurrence of a bladder tumor and more than two tumors in the UUT had a significant influence on the rate of bladder tumor recurrence. On the other hand, location, mode of growth, grade, stage and vascular invasion of the UUT tumor, and history of bladder tumors did not seem to be related to the frequency of subsequent bladder tumors. These findings suggest that the diversity of UUT tumors at the time of diagnosis is an important factor in bladder tumor recurrence. Therefore, clinical and pathological examinations should be carefully performed in patients with UUT tumors.

Aged↗
PubMed1991

Plasma endothelin concentrations in patients with pulmonary hypertension associated with congenital heart defects. Evidence for increased production of endothelin in pulmonary circulation.

BACKGROUND: To elucidate the pathophysiological significance of endothelin in pulmonary hypertension associated with congenital heart defects, we measured plasma endothelin-like immunoreactivity (ET-LI) concentrations by using radioimmunoassay in 18 patients with pulmonary hypertension (PH group; age, 6 months to 12 years) in comparison with 27 patients without pulmonary hypertension (non-PH group; age, 6 months to 12 years). METHODS AND RESULTS: Blood samples were obtained from the vena cava, right atrium, right ventricle, left or right pulmonary artery, and pulmonary vein or the pulmonary arterial wedge position (pulmonary venous blood) during cardiac catheterization. Plasma ET-LI concentrations in the PH group were significantly higher than those in the non-PH group at all sampling sites. In the PH group, plasma ET-LI concentration showed a significant increase between the right ventricle and pulmonary artery and between the pulmonary artery and pulmonary vein. The increment of plasma ET-LI concentrations from the right ventricle to the pulmonary vein was significantly larger in the PH group than in the non-PH group and was significantly correlated with pulmonary artery pressure. CONCLUSIONS: Plasma ET-LI concentrations were elevated in patients with pulmonary hypertension; the elevation was due to the increased production of ET-LI in pulmonary circulation, indicating the possible involvement of endothelin in the pathophysiology of pulmonary hypertension.

Blood Pressure↗
PubMed1991

Protein adsorption on biomedical polymers with a phosphorylcholine moiety adsorbed with phospholipid.

The effects of phospholipid adsorption onto the polymer surface during adsorption of plasma proteins were investigated. When a polymer with the phosphorylcholine moiety, 2-methacryloyloxyethyl phosphorylcholine (MPC) co-polymer, was treated with dipalmitoylphosphatidylcholine (DPPC) liposome solution, an organized adsorption layer of DPPC was formed on the MPC co-polymer surface, which was confirmed by differential scanning calorimetric analysis and X-ray photoelectron spectroscopy. On the other hand, an organized layer of DPPC on poly(n-butyl methacrylate) and poly(2-hydroxyethyl methacrylate) could not be found. The amount of albumin adsorbed on the polymer surfaces was decreased by pretreatment of the surface with DPPC liposome solution in every polymer case. The smallest amount of adsorbed proteins was found on the MPC co-polymer. Protein adsorption on the surface of MPC co-polymers from the plasma was also small. The difference in protein adsorption on the polymers probably reflects the difference in the orientation of the phospholipid molecules which cover the polymer surface.

Adsorption↗
PubMed1991

Inherited type of allelic methylation variations in a mouse chromosome region where an integrated transgene shows methylation imprinting.

It is still unclear whether or not parent-of-origin-dependent differential methylation observed in some transgenes reflects genomic imprinting of endogenous genes. We have characterized a transgene locus showing such methylation imprinting together with the corresponding native chromosome region. We show that only part of the transgene is affected by methylation imprinting and the methylation pattern is established before early prophase I during spermatogenesis. Interestingly, the native genomic region, which is mapped to the proximal chromosome 11, shows no evidence of methylation imprinting but displays heritable, strain-specific type of allelic methylation differences. The results demonstrate that transgenes do not necessarily reflect the methylation status of either the surrounding or corresponding chromosome region. In addition, inherited type of allelic methylation variations previously described in human may be widespread in mammals.

Animals↗
PubMed1991

Studies on the chemical modification of monensin. III. Synthesis and sodium ion transport activity of macrocyclic monensylamino acid-1,29-lactones.

Monensylglycine (2a) was lactonized to macrocyclic monensylglycine-1,29-lactone (3a) by Corey's method. Lactonization of monensylamino acids (2b--d) to monensylamino acid-1,29-lactones (3b--d) was carried out by utilizing the template effect of K+ ion. Monobenzyl esters of dicarboxylic monensylamino acids (5e--f) also were lactonized followed by debenzylation to yield carboxylic monensylamino acid-1,29-lactones (3e--f). Sodium ion transport activity of monensin (1) and the lactones (3) was measured in a liquid membrane and in guinea pig erythrocyte membrane. Monensylaspartic acid-1,29-lactone (3e) exhibited 2.5 times higher activity than 1 in the liquid membrane. Monensylalanine-1,29-lactone (3b), monensylphenylalanine-1,29-lactone (3c), and monensyltyrosine-1,29-lactone (3d), having smaller Na+ ion transport activity than 3e, showed weak antibacterial activity, while 3e was inactive in biological tests, probably due to the lower lipophilicity.

Animals↗
PubMed1991

Studies on cardiac ingredients of plants. VII: Chemical transformation of proscillaridin by means of the Diels-Alder reaction and biological activities of its derivatives.

The Diels-Alder reactions of a cardiac glycoside, proscillaridin (1), with some dienophiles were investigated. The reaction of 1 with alkenes such as methyl vinyl ketone and methyl acrylate afforded 3-oxo-2-oxabicyclo[2.2.2]oct-7-enes (2-5) and para-substituted benzene derivatives (6 and 7), while 1 reacted with alkynes (3-butyn-2-one, methyl propiolate) to yield para- or meta-substituted benzene derivatives (6-9). The biological activities of the resulting derivatives were evaluated by the use of isolated guinea-pig papillary muscle preparations and Na+,K(+)-adenosine triphosphatase (ATPase) preparation from dog kidney. Among the proscillaridin derivatives, compounds 4 and 7 moderately inhibited Na+,K(+)-ATPase activity. Furthermore, the concentration range of 7 over which its positive inotropic effect on guinea-pig papillary muscle preparations, increased from 5% to 95% of maximum was broader than that of 1, i.e., concentration dependency was maintained over a greater range of concentration.

Adenosine Triphosphatases↗
PubMed1991

Studies on glycolipids. III. Glyceroglycolipids from an axenically cultured cyanobacterium, Phormidium tenue.

Seven new monogalactosyl diacylglycerols (1-7) and six new digalactosyl diacylglycerols (11-16) were isolated from an axenically cultured cyanobacterium, P. tenue. Their structures were elucidated on the basis of physicochemical evidence and the results of enzymatic hydrolysis using a lipase (from Rhizopus arrhizus). Comparison of antialgal activity for P. tenue between monogalactosyl diacylglycerols (1-8) and digalactosyl diacylglycerols (11-19) revealed that the former showed more potent activity than the latter.

Cyanobacteria↗
PubMed1991

[Studies on cardiac ingredients of plants. VIII. Preparation of nitrates of proscillaridin and their pharmacological activities].

To reduce the vascular contracting effect of the cardiac glycoside, proscillaridin (1), all kinds of its nitrates were prepared by utilizing effectively an isopropylidene function as a protective group. The pharmacological activities of proscillaridin nitrates were evaluated by the use of isolated guinea-pig papillary muscle preparations and Na+,K(+)-adenosine triphosphatase preparations from the dog kidney. Furthermore, the effect for smooth muscle using the helical strips isolated from 13-week old spontaneously hypertensive rat was examined. The positive inotropic effects and Na+, K(+)-adenosine triphosphatase inhibition activities of mononitrates (6, 9, 15) and dinitrates (3, 4, 5) were a little less potent than 1, but those of trinitrate (2) were much reduced. Every nitrate did not exhibited a vascular contracting effect but a relaxing effect. Among them, the vascular relaxing effects of 2',3'-dinitrate (3) and 2',4'-dinitrate (4) were more potent than those of the other nitrates.

Animals↗
PubMed1991

[Assessment of occupational exposure to p-tert-butylphenol in synthetic resin factories].

Two cases of occupational vitiligo were observed in a resin factory where p-tert-butylphenol (PTBP) has been used as a starting material or an intermediate of synthetic resin. In this resin factory (A shop) and another resin factory (B shop), occupational exposure to PTBP was assessed in workers charging this chemical into the reaction vessel by means of a gas-chromatographic measurement of the environmental PTBP concentration and their urinary PTBP excretion. Assessment in A shop was made after the working condition was partly improved. Geometrical mean values of 8 h-time-weighted-average (8 h-TWA) of PTBP in air near the charger's breathing zone (personal air) were 0.215 mg/m3 in A shop and 2.12 mg/m3 in B shop. Continuous measurements of PTBP concentration in some stationary air of the shops showed that the maximum environmental PTBP values occurred during charging. Urinary PTBP concentration was increased to the maximum values 2 to 4 h after charging of this chemical and then rapidly decreased. Biological half-lives of urinary PTBP were estimated as 4.4 h in A shop and 4.8 h in B shop. The urinary PTBP concentration was correlated to 8 h-TWA of PTBP in the personal air. In particular, PTBP in urine collected at the end of the shift showed an excellent correlation to PTBP in the personal air (r = 0.84, n = 9, A shop; r = 0.88, n = 11, B shop). These results indicate that biological monitoring using urinary PTBP concentration is a suitable means of assessing exposure to this alkylphenol and the urine collected at the end of shift is the best sample for monitoring. In addition, the present environmental and urinary PTBP values were compared with those described in the literature and the relation of the occupational vitiligo with PTBP exposure is discussed.

Chemical Industry↗
PubMed1991

Experimental studies on the pharmacokinetics and nephrotoxicity of carboplatin (cis-diammine-1, 1-cyclobutane dicarboxylate platinum II) in rats.

To study the nephrotoxicity of carboplatin (cis-diammine-1, 1-cyclobutane dicarboxylate platinum II, CBDCA), an analogue of cisplatin, we examined its pharmacokinetics and functional and histopathological changes of the kidney in rats that received i.v. injection of carboplatin. Platinum concentrations in the whole plasma rapidly decreased during the first 2 hours and was undetectable at 72 hours following the carboplatin administration. Approximately 90% of the platinum in the whole plasma was ultrafilterable during the first 30 minutes. The renal tissue concentrations of platinum rapidly decayed during the first 4 hours and then slowly declined up to 120 hours following the carboplatin administration. Platinum concentrations in the renal cortex showed higher levels than those in the renal medulla throughout the experimental period. BUN levels were within the normal range except on day 7. Serum creatinine levels remained stable and normal during the 7 days. Histopathological alterations of the renal tubules were not observed during the experimental period. These results suggest that carboplatin has less nephrotoxicity than cisplatin, because of its rapid excretion through glomerulus and less accumulation in the tubular cells.

Animals↗
PubMed1991

[Study on recurrence of hypertensive intracerebral hemorrhage].

Recurrence of hypertensive intracerebral hemorrhage confirmed by computed tomography scan has rarely been reported. The authors have experienced nine cases of recurrent hemorrhage among 494 cases of hypertensive intracerebral hemorrhage. Recurrence rate was 1.8%. There were eight males and one female with an average age of 60.5 years. Six cases had their first and second attacks in ganglionic regions. Among them, three cases had the second attack in the ipsilateral side, and the other three cases had the second attack in the contralateral side. Two cases had the first attack in the thalamic and the second in the cerebellar regions. One case had the first attack in the pontine and the second in the putaminal regions. Intervals between the first and second attacks were within 6 months for ipsilateral ganglionic attacks and over 4 years for contralateral ganglionic attacks. In all cases systemic blood pressure was normalized or well controlled by antihypertensive agents after the first attack. The mechanism of rebleeding has not been clarified.

Activities of Daily Living↗
PubMed1991

Diminished specific activity of cytosolic protein kinase C in sciatic nerve of streptozocin-induced diabetic rats and its correction by dietary myo-inositol.

The impaired Na(+)-K(+)-ATPase activity in peripheral nerve from diabetic rats is prevented by dietary myo-inositol (MI) supplementation in vivo and corrected by protein kinase C (PKC) agonists in vitro, suggesting that PKC may mediate the effects of nerve MI depletion on Na(+)-K(+)-ATPase activity. However, little is known about the effect of diabetes on PKC activity or peptide in rat peripheral nerve. Therefore, the effect of streptozocin-induced diabetes and dietary MI supplementation on the activity and distribution of PKC in rat sciatic nerve homogenates and cytosolic and particulate fractions was explored with histone phosphorylation assay and Western-blot analysis. PKC activity but not peptide was selectively decreased in the cytosolic fraction by streptozocin-induced diabetes, and this abnormality was partially corrected by dietary MI supplementation. These results suggest that altered MI metabolism may affect nerve PKC specific activity, and this alteration may play a role in reduced Na(+)-K(+)-ATPase activity and blunted regenerative response in diabetic nerve.

Administration, Oral↗
PubMed1991

The effect of microtubule stabilizer on rat caerulein-induced pancreatitis.

Inhibition of pancreatic digestive enzyme secretion in the acinar cell is a significant phenomenon which can trigger acute pancreatitis. It has been shown that microtubules are responsible for the intracellular vesicular transport. The effect of taxol, a microtubule stabilizer, was examined in a model of acute edematous pancreatitis induced in rats by supramaximal stimulation with cholecystokinin analogue, caerulein. Prophylactic administration of taxol ameliorated inhibition of pancreatic digestive enzyme secretion, increased level of serum amylase, pancreatic edema, and histological alterations in this model. Immunofluorescence studies revealed that taxol stabilized the arrangement of microtubules by promoting tubulin polymerization. On the other hand, microtubule disorganization was found in rats without prophylactic taxol treatment. In caerulein-treated rats, there is microtubule disorganization which causes interference with intracellular vesicular transport leading to inhibition of pancreatic digestive enzyme secretion--a forerunner of acute pancreatitis. Taxol was found to prevent these events.

Alkaloids↗
PubMed1991

Cell-free translation system using phosphorothioate-containing mRNA.

Phosphorothioate-containing RNAs were generated by transcription of template DNA using the Sp diastereomers of ribonucleoside 5'-O-(1-thiotriphosphates) (NTP alpha S) and T7 RNA polymerase. The substitution of mRNA by phosphorothioate increased the efficiency of protein synthesis by stabilizing the mRNAs in prokaryotic cell-free translation systems. The substituted mRNAs were also shown to be applicable to the continuous cell-free translation system developed by Spirin and coworkers.

Escherichia coli↗
PubMed1991

Structure of mitochondrial tRNA.

Some mitochondrial (mt) tRNAs are presumed to have unusual secondary structures on the basis of DNA sequence analyses. However there are few tRNAs whose structures have been investigated at RNA level. Thus we isolated some mt tRNAs to investigated their structures and also synthesized mt tRNA by run-off transcription. In these experiments, following results have been obtained. 1) Bovine mt tRNA(Ser)(AGY) needs the interaction between the T-loop and D-arm for its aminoacylation activity. 2) The secondary structure of bovine mt tRNA(Ser)(UCN) is difficult from that predicted previously from its gene. 3) It has been confirmed by the hybridization using oligonucleotide probes that some Ascaris suum mt tRNAs possessing the unusual T-arms actually exist in its mitochondria.

Animals↗
PubMed1991

[A study of dental status and its contributing factors in mentally retarded persons institutionalized in welfare facilities].

Two hundred and forty-one mentally retarded persons, institutionalized in three private welfare facilities in Oita Prefecture, were assessed for dental status and tooth brushing ability. Information on their life style was also obtained by a questionnaire completed by their supervisors in the facilities. 1) Dental status of mentally retarded subjects was found to be inferior compared to the general Japanese population studied in the survey of dental disease in 1987 by the Ministry of Health and Welfare. Inferior dental status was characterized by a low score for filled teeth and a high score for missing teeth. 2) Both low tooth brushing ability and low intelligence quotient were associated with their poor dental status. 3) Discrepancy between supervisor assessment of tooth brushing ability and actual ability was observed. 4) Periodontitis was observed in young epileptics taking antiepileptic medication at a high rate. However there was no association between the taking of antiepileptic medication and missing teeth score. These results indicate a necessity for more active dental services including the teaching of tooth brushing and early treatment by dentists and supervisors.

Adolescent↗