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Biomedical subjects

T Ueda

Publications and source records attributed to T Ueda.

At least 235 records · Page 13Linked to original sources
PubMed1993

Discordant LFA-1/ICAM-1 expression in a case of secondary plasma cell leukemia associated with subcutaneous plasmacytoma.

We observed a unique case of multiple myeloma that was transformed into plasma cell leukemia presenting with subcutaneous and soft tissue infiltrates. Subcutaneous and minor pelvic soft tissue plasmacytomas and the leukemic transformation were diagnosed in a 72-year-old woman after she had completed 9 months of chemotherapy for IgG kappa multiple myeloma. Immunophenotypic study revealed that leukemic cells in her peripheral blood were positive for ICAM-1 (CD54) but negative for LFA-1 alpha (CD11a) and LFA-1 beta (CD18), whereas infiltrating leukemic cells in the subcutaneous plasmacytoma of the left thigh were positive for LFA-1 alpha and LFA-1 beta but negative for ICAM-1. In addition, intermingling capillary endothelial cells were positive for ICAM-1. Extramedullary soft tissue plasmacytoma is uncommon in association with plasma cell tumors, and the exact mechanism of the development of plasmacytoma is not known. In the present case, however, the discordant expression of LFA-1/ICAM-1 adhesion molecules may have accounted for the distinct patterns of growth and the spread of the subcutaneous plasmacytoma through homing of the LFA-1 alpha+, LFA-1 beta+ leukemic cells to ICAM-1+ endothelial cells.

Aged↗
PubMed1993

Depolarization of Raman scattering from some nucleotides of RNA and DNA.

Depolarization ratios of Raman bands, excited at 488.0 nm, of guanosine-5'-monophosphoric acid, cytidine-5'-monophosphoric acid, adenosine-5'-monophosphoric acid, thymidine-5'-monophosphoric acid, and uridine-5'-monophosphoric acid have been measured in their H2O and D2O solutions in the spectral region from 300 to 1800 cm-1. For comparison, the disodium salt of 2'-deoxyadenosine-5'-monophosphoric acid was also subjected to the depolarization measurement in its H2O solution. The results have been correlated with possible orientations of the principal axes of the Raman scattering tensors as well as with the relative magnitudes of the tensor components. Results should be useful for future polarized Raman studies of synthetic and natural DNA.

DNA↗
PubMed1993

Effects of phospholipid adsorption on nonthrombogenicity of polymer with phospholipid polar group.

Polymers with phospholipid polar groups, 2-methacryloyloxyethyl phosphorylcholine (MPC) polymers, have excellent nonthrombogenic properties. The effects of adsorption of phospholipids on platelet adhesion and activation on the MPC copolymer with n-butyl methacrylate (BMA) were investigated with particular attention to the structure of the phospholipids adsorbed onto the polymer surface. The electrical nature of the phospholipids adsorbed on the polymer surface affected the thrombogenicity of the polymer. On the MPC polymer surface treated with an aqueous liposomal solution of acidic phospholipids, phosphatidylserine, platelet adhesion and activation occurred to a greater extent when compared to a poly(MPC-co-BMA) surface. However, on the MPC polymer surface treated with electrically neutral phosphatidylcholines, reduced thrombogenicity could be observed. Therefore, the adsorption of the phosphatidylcholines was an important factor in reducing the thrombogenicity on the polymers. Moreover, by comparison of the poly(MPC-co-BMA) to a poly(BMA), platelet adhesion and activation on these polymer surfaces depended on the adsorption state of the phosphatidylcholines. The amount of phosphatidylcholine adsorbed on the poly(MPC-co-BMA) increased with an increase in the MPC mole fraction of the copolymer. This indicates that the MPC moieties have affinity for the phosphatidylcholines. We conclude that the poly(MPC-co-BMA) can adsorb large amounts of phosphatidylcholines and that these phospholipids organize themselves. The organized adsorption layer of the phosphatidylcholines on the surface, which construct biomembrane-like surfaces, can reduce platelet adhesion and activation effectively.

1,2-Dipalmitoylphosphatidylcholine↗
PubMed1993

Immediate-type allergy related to okra (Hibiscus esculentus Linn) picking and packing.

Two workers (cases A and B) engaged in picking and packing okra who had complaints of work-related allergic symptoms showed distinct positive intradermal reactions to two brands of okra extracts only with thresholds of 1 x 10(-8) w/v for Case A and 1 x 10(-6) w/v for Case B. Both also showed positive reactions to okra extracts in the Prausnitz-Küstner test and in the provocative nasal test. The radioallergosorbent test scores to the okra extract were determined to be 2 (defined as clear positive) for Case A and 1 (border line) for Case B. These findings indicated that the allergic conditions of these cases were from an IgE-mediated immediate-type allergy induced by handling okra. To confirm the etiology of the two cases 14 farmers engaged in picking and packing okra were examined. Among them, 8 subjects (57%) showed positive intradermal reactions to okra extracts. A close association between intradermal reactions to okra extracts and complaints of work-related allergic symptoms was seen in these subjects. These results confirm that the okra may be capable of inducing IgE-mediated immediate-type allergy to workers handling okra.

Adult↗
PubMed1993

Time sequential single photon emission computed tomography studies in brain tumour using thallium-201.

Time sequential single photon emission computed tomography (SPECT) studies using thallium-201 were performed in 25 patients with brain tumours to evaluate the kinetics of thallium in the tumour and the biological malignancy grade preoperatively. After acquisition and reconstruction of SPECT data from 1 min post injection to 48 h (1, 2, 3, 4, 5, 6, 7, 8, 9, 10 and 15-20 min, followed by 4-6, 24 and 48 h), the thallium uptake ratio in the tumour versus the homologous contralateral area of the brain was calculated and compared with findings of X-ray CT, magnetic resonance imaging, cerebral angiography and histological investigations. Early uptake of thallium in tumours was related to tumour vascularity and the disruption of the blood-brain barrier. High and rapid uptake and slow reduction of thallium indicated a hypervascular malignant tumour; however, high and rapid uptake but rapid reduction of thallium indicated a hypervascular benign tumour, such as meningioma. Hypovascular and benign tumours tended to show low uptake and slow reduction of thallium. Long-lasting retention or uptake of thallium indicates tumour malignancy.

Brain↗
PubMed1993

Contribution of differentiated ratings of perceived exertion to overall exertion in women while swimming.

The purpose of this study was to identify, using multiple regression analysis, the contribution of differentiated ratings of perceived exertion to overall exertion (RPEO) in women while swimming. Ten female subjects swam at submaximal and maximal intensities and the variables measured included oxygen uptake (VO2), heart rate (fc), ventilation (VE), breathing frequency, tidal volume, blood lactate concentration ([la-]b), RPEO, and four differentiated RPE. These four differentiated RPE were cardiac frequency rating (RPEC), respiratory frequency rating (RPER), arm rating (RPE(arm)), and leg rating (RPE(leg)). These variables used the following equation based on VO2 - R = a + c.(S-b)n, where R was the response to increasing exercise intensity (S) and a, b, and c were constants. The exponents (n) of fc, VE and [la-]b were approximately 1.0, 2.0 and 3.3, respectively. The estimated exponents of RPEO, RPEC, RPER, RPE(arm) and RPE(leg) were approximately 2.4, 2.3, 2.2, 2.5 and 2.5, respectively. There was a highly significant relationship between the four differentiated RPE and their associated physiological responses. The results of this study showed that these interrelationships were clearly delineated. As the percentage maximal oxygen uptake (% VO2max) increased, the major contributing factor to RPEO changed. The RPEC was found to be the main contributing factor from 20% to 45% VO2max, but ceased to contribute beyond 50% VO2max. Above 45% VO2max, RPE(arm) was the major influence, and RPER was the secondary influence from 66% to 96% VO2max. The RPE(leg) was the secondary contributing factor only from 27% to 35% VO2max. It was concluded that differentiated RPE contribution was dependent upon the intensity of exercise in women while swimming.

Adult↗
PubMed1993

Glutamate uptake system in the presynaptic vesicle: glutamic acid analogs as inhibitors and alternate substrates.

A variety of naturally occurring amino acids, their isomers, and synthetic analogs were tested for their ability to inhibit uptake of [3H]glutamate into presynaptic vesicles from bovine cerebral cortex. Strongest inhibition (Ki < 1mM) was observed for trans-1-aminocyclopentane-1,3-dicarboxylic acid (t-ACPD) and erythro-4-methyl-L-glutamic acid (MGlu), while 4-methylene-L-glutamic acid (MeGlu) was only moderately inhibitory (Ki = approximately 3mM), indicating that the synaptic vesicle glutamate translocator has higher affinity for trans-ACPD and MGlu than for glutamate. A few other amino acids, e.g., 4-hydroxyglutamic acid, S-carboxyethyl cysteine, and 5-fluorotryptophan, were slightly inhibitory; all L- and DL-isomers of protein amino acids and longer chain acidic amino acids were without measurable inhibition. Potassium tetrathionate and S-sulfocysteine exhibited strong to moderate noncompetitive or irreversible inhibition. Inhibition by t-ACPD, MGlu, or MeGlu was competitive with glutamic acid. Each of these competitive inhibitors was also taken up by the vesicle preparation in an ATP-dependent manner, as indicated by their being recovered unchanged from filtered vesicles. Similar results were obtained with reconstituted vesicles, while glutamate uptake by partially purified rat synaptosomes was inhibited only by MGlu. These results indicate that the glutamate translocator of presynaptic vesicles has stringent structural requirements distinct from those of the plasma membrane translocator and the metabotropic type of postsynaptic glutamate receptor. They further suggest possible structural requirements of pharmacologically significant compounds that can substitute for glutamic acid in the presynaptic side of glutamatergic synapses, thus serving to moderate or control glutamate excitation and associated excitotoxic effects in these neurons.

Animals↗
PubMed1993

The evolutionary change of the genetic code as restricted by the anticodon and identity of transfer RNA.

The discovery of non-universal genetic codes in several mitochondria and nuclear systems during the part ten years has necessitated a reconsideration of the concept that the genetic code is universal and frozen, as was once believed. Here, the flexibility of the relationship between codons and amino acids is discussed on the basis of the distribution of non-universal genetic codes in various organisms insofar as has been observed to date. Judging from the result of recent investigations into tRNA identity, it would appear that the non-participation of the anticodon in recognition by aminoacyl-tRNA synthetase has significantly influenced the variability of codons.

Animals↗
PubMed1993

Codons AGA and AGG are read as glycine in ascidian mitochondria.

A 1.2-kb DNA fragment of the cytochrome oxidase subunit I (CO I) gene of mitochondria isolated from an ascidian, Halocynthia roretzi, was amplified by polymerase chain reaction (PCR) and sequenced. Codons AGA and AGG appeared in its reading frame, indicating that these are sense codons in this organelle. Sequence comparisons with the corresponding regions of other animal mitochondrial CO I genes suggest that codons AGA and AGG correspond to glycine in the ascidian mitochondrial genome, but not to serine as in most invertebrate genomes, nor to stops as in vertebrate genomes. The other codons are identical to those of vertebrate mitochondria.

Amino Acid Sequence↗
PubMed1993

Prophylactic effect of methylprednisolone against cisplatin-induced nephrotoxicity in rats.

Male Sprague-Dawley rats were intravenously injected with 6.5 mg/kg of cisplatin combined with a subcutaneous methylprednisolone (MP) injection to study the prophylactic effects of steroid hormone on cisplatin-induced nephrotoxicity. In Expt. 1, the rats were injected twice with either 10, 20 or 50 mg/kg of MP4 and 0 h prior to the cisplatin injection and in Expt. 2, they were given a single injection of 100 mg/kg of MP either 24, 4, 2 or 0 h prior to the cisplatin injection. In Expt. 1, elevations of the BUN and serum creatinine levels caused by the cisplatin were dose-dependently inhibited by the administration of MP. In the second experiment, BUN and serum creatinine levels in rats which were pretreated with MP 4 or 2 h prior to the cisplatin injection were significantly lower than those in rats which received cisplatin alone. Our preliminary results suggest that pretreatment with MP is an effective means of protection against cisplatin-induced nephrotoxicity.

Animals↗
PubMed1993

3'-end processing of the maize 27 kDa zein mRNA.

Cis-regulatory elements involved in the mRNA 3'-end processing of the 27 kDa zein gene have been investigated by deletion and site-directed mutagenesis analyses. In the 3' flanking region of the 27 kDa zein gene, several AATAAA-like sequences and a sequence resembling the mammalian GT-rich sequence are present around the polyadenylation sites. Among the multiple AATAAA-like sequences, the duplicated AATGAA motifs, located 30-40 bp upstream from the polyadenylation sites, have been shown to play roles as polyadenylation signals. Although either of the two AATGAA motifs can function as a polyadenylation signal in chimeric gene constructs, the one proximal to the polyadenylation sites is likely to be the functional polyadenylation signal in the 27 kDa zein gene. Deletion of the downstream GT-rich sequence as well as alteration of the sequence surrounding the poly-adenylation sites has little effect on the mRNA 3'-end processing. However, the sequence elements located upstream from the polyadenylation signals are essential for the mRNA 3'-end processing. Mutations in the AATGAA motifs or the upstream sequences reduced the level of a reporter gene expression. A model depicting the mechanism involved in the 3'-end processing of the 27 kDa zein mRNA is presented.

Base Sequence↗
PubMed1993

Signal intensity of brain metastases on T2-weighted images: specificity for metastases from colonic cancers.

In this report, we present and discuss the signal intensity of brain metastases from colon cancer on both T1- and T2-weighted images. In five of 6 cases, metastases were seen as markedly hypointense areas on T2-weighted images. This finding should alert one to the possibility of a primary cancer of the colon. Some haemorrhagic metastases from other malignancies also showed marked hypointensity. They usually exhibited hyperintensity on T1-weighted images. A case of colon metastasis was also haemorrhagic, and in this case a hyperintense area was observed on T1-weighted images. The marked hypointense area corresponded to peripheral necrosis and probably some viable tumour. Aetiologically, such hypointensity was not induced by severe fibrosis, calcification or excessive iron deposition.

Adolescent↗
PubMed1993

Detection of subtle differences in the surface structure of lysozymes by use of an immobilized Fab fragment.

A method was developed to evaluate the association constant at physiological pH (pH 7.5) between a lysozyme and the Fab fragment derived from anti-lysozyme monoclonal antibody 37-7, which was immobilized to the adsorbent for HPLC. Comparison of the association constants between lysozymes and the immobilized Fab fragment indicated that mAb 37-7 recognized the prominently exposed regions (hills and ridges) around His15 of hen lysozyme, but His15 itself was not directly involved in the binding with mAb 37-7. Moreover, the epitope was confirmed by the reactivity of His15 with monoiodoacetic acid in the presence of mAb 37-7. The association constant of 15-carboxymethylated histidine lysozyme (15CM lysozyme) with the immobilized Fab fragment was smaller by one-seventh than that of 15-carboxamidated histidine lysozyme, though the side chains introduced were almost identical in size. From the pH titration of 15CM lysozyme with 13C-enriched carboxyl group by use of 13C-NMR, the pKa of the introduced carboxyl group was evaluated to be 5.06. Since the carboxyl group was fully ionized under the conditions of measurement (pH 7.5), electrostatic repulsion was found to disturb severely the association between mAb 37-7 and hen lysozyme. Moreover, it was demonstrated that, because of the high reproducibility of measurement, the immobilized Fab fragment could detect subtle differences in the surface structure of lysozymes.

Animals↗
PubMed1993

Thermodynamic and kinetic stabilities of hen-egg lysozyme and its chemically modified derivatives: analysis of the transition state of the protein unfolding.

For the stabilization of a protein against irreversible denaturation caused by rapid reaction of the unfolded form of the protein (kinetic stabilization), the free energy change of activation for unfolding should be increased. First, we demonstrated that this strategy was effective to stabilize a protein against protease digestion. For kinetic stabilization, it is important to stabilize a protein at a site where the local structures are largely unfolded in the transition state for unfolding. We developed a method to find such sites by comparison of the thermodynamic stabilities and the unfolding rate constants between unmodified and modified proteins. Application of this method to analyze the transition state of hen-egg lysozyme using some chemically modified derivatives is also described. Moreover, it was confirmed that the protease digestion method is superior to the relaxation method for estimation of the unfolding rate constant. Namely, the protease digestion method may be useful in analyzing the transition state of protein unfolding.

Animals↗
PubMed1993

Effects of polyamines on a continuous cell-free protein synthesis system of an extreme thermophile, Thermus thermophilus.

A continuous cell-free protein synthesis system of an extremely thermophilic eubacterium, Thermus thermophilus HB27, was constructed. This system produced MS2 phage RNA translation products at a rate of more than 5 micrograms per hour per 1.9 mg of ribosomes at 65 degrees C and the production continued linearly for at least 340 min. When no polyamine was added, the system did not produce the proteins. The highest activity was recorded when 0.1 mM tetrakis(3-aminopropyl)ammonium and 1.0 mM spermine were added simultaneously.

Bacterial Proteins↗
PubMed1993

Stabilization of lysozyme by the introduction of Gly-Pro sequence.

Three mutant lysozymes where the Asp101-Gly102 sequence of lysozyme was converted to Asp101-Pro102, Gly101-Pro102 and Pro101-Gly102 were prepared to investigate the effect of proline residues on the stabilization of proteins. The free energy changes of lysozymes for the unfolding in aqueous solution at pH 5.5 and 35 degrees C were 10.0, 10.1, 11.0 and 7.7 kcal/mol for wild type, Asp101Pro102, Gly101Pro102 and Pro101Gly102 lysozyme respectively. When the energy level in the unfolded state of wild type lysozyme was fixed at a standard level, the energy levels in the folded state of Asp101Pro102 and Pro101Gly102 lysozymes were found to be higher than that of wild type lysozyme on the basis of delta GD(H2O) and entropy losses of their polypeptide chains in the unfolded state. The presence of some strain in the folded state of these lysozymes was supported by both the calculation of conformational energy for a trans-L-prolyl residue [Schimmel, P.R. and Flory, P.J. (1968) J. Mol. Biol., 34, 105-120] and the analysis of structures of energy-minimized mutant lysozymes. Therefore, it is concluded that the formation of the Gly-Pro sequence is effective in avoiding possible strain in the folded state of a protein caused by the introduction of proline residue(s).

Amino Acid Sequence↗
PubMed1993

Absence of hepatic uptake of Tc-99m phytate in a man with chronic toluene hepatotoxicity.

The case reported here is of a 28-year-old man diagnosed as having toluene hepatotoxicity. He had a 5-year history of exposure to toluene and was admitted to hospital complaining of two episodes of loss of consciousness. The high total bilirubin and the low prothrombin time suggested serious liver dysfunction. Based on histologic examination of a liver biopsy specimen, the diagnosis of toxic liver dysfunction caused by toluene poisoning was made. Hepatic images were not present in Tc-99m phytate scintigrams, but they were present in hepatobiliary scintigrams done with the Tc-99m N-pyridoxyl-5-methyltryptophan. The diagnosis of hepatic reticuloendothelial failure was made.

Adult↗