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Biomedical subjects

K Ueda

Publications and source records attributed to K Ueda.

At least 973 records · Page 54Linked to original sources
PubMed1990

Serum hemolytic activity in dogs infected with Babesia gibsoni.

The hemolytic activity in serum of Babesia gibsoni-infected dogs was examined. When the activity was assayed in a reaction system consisting of similar concentrations of the serum and canine red blood cells to those in blood, significant hemolysis was observed. The activity of the serum of B. gibsoni-infected dogs, either naturally or experimentally, was always higher than that of uninfected animals. Moreover, in the experimental infection with B. gibsoni, the change in serum hemolytic activity was parallel to those of anemia and parasitemia, whereas it was inversely parallel to that of the hematocrit value. The present study revealed the presence of a hemolytic factor(s) in the serum of B. gibsoni-infected dogs, suggesting that the progressive anemia was due to hemolysis by the factor(s).

Anemia, Hemolytic↗
PubMed1989

Tissue-specific expression of three types of beta-protein precursor mRNA: enhancement of protease inhibitor-harboring types in Alzheimer's disease brain.

Expression of three types of mRNA encoding amyloid beta-protein precursor (APP) in various tissues was analysed, using a ribonuclease protection assay, with special reference to Alzheimer's disease (AD). The total content and the proportion of APP mRNAs were specific to each tissue. Among eight tissues examined, the brain was distinct in that the expression level was highest and APP695 mRNA was expressed in abundance. The ratio of APP770/APP751/APP695 mRNAs was approximately 1:10:20 in the cerebral cortex of control brain. The proportions of APP770 mRNA and APP770-plus-APP751 mRNAs increased up to 2.6- and 1.4-fold, respectively, in various regions of AD brain compared with control. The enhanced expression of protease inhibitor-harboring types (APP770 and APP751) may disturb the balance between biosynthesis and degradation of APPs and ultimately lead to accumulation of beta-protein as amyloid.

Aged↗
PubMed1989

After-effects of moving textured background in motion-sensitive neurons of anuran optic tectum.

Motion-sensitive neurons in anuran optic tectum were shown to respond to a stationary object centered in the excitatory receptive field, if a textured background moved for a while and then stopped ('motion after-response'). This motion after-response was attributed to a post-inhibitory rebound activation derived from effects of masking the excitatory receptive field center surrounded by an antagonistic inhibitory region. It was suggested that a similar rebound activation mechanism may also be involved in a certain type of perceptual motion after-effects in humans.

Action Potentials↗
PubMed1989

[Clinical results of hyperthermia alone in the treatment of refractory human tumors].

Retrospective analysis of patients with refractory tumors which were treated with hyperthermia alone in five institutions was performed. Hyperthermia was applied to 30 refractory tumors including 19 deep-seated tumors for a total of 427 sessions by 8 MHz or 13.56 MHz radiofrequency capacitive heating devices. Of the 30 tumors treated, 3 (10%) showed complete regression and 2 (7%) more than 50% regression. Although tumor regression was observed in small tumors, large deep-seated tumors did not respond to heat alone. Thus, response rate of hyperthermia alone was lower than expected, although subjective improvement by hyperthermia was noted in 53% patients. We consider that hyperthermia should be combined with radiation or chemotherapy whenever possible.

Adult↗
PubMed1989

Deletion and insertion mutants of the multidrug transporter.

The multidrug transporter is a 170,000-dalton membrane glycoprotein which confers multidrug resistance through its activity as an ATP-dependent efflux pump for hydrophobic, cytotoxic drugs. To determine the essential structural components of this complex membrane transporter we have altered an MDR1 cDNA in an expression vector by deletion and insertion mutations. The structure of the transporter deduced from its amino acid sequence suggests that it consists of two homologous, perhaps functionally autonomous, halves each with six transmembrane segments and a cytoplasmic ATP-binding domain. However, several carboxyl-terminal deletions, one involving 53 amino acids, the second removing 253 amino acids, and an internal deletion within the carboxyl-terminal half of the molecule, totally eliminate the ability of the mutant transporter to confer drug resistance. An internal deletion of the amino-terminal half, which removed residues 140-229, is also nonfunctional. Small carboxylterminal deletions of up to 23 amino acids leave a functional transporter, although the removal of 23 COOH-terminal amino acids reduces its ability to confer colchicine resistance. Insertions of 4 amino acids in a transmembrane domain, and in one of the two ATP-binding regions, have no effect on activity. These studies define some of the limits of allowable deletions and insertions in the MDR1 gene, and demonstrate the requirement for two intact halves of the molecule for a functional multidrug transporter.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1989

[Clinical effects of hyperthermia treatment for recurrent bladder cancer].

The usefulness of the application of thermotherapy for cases of recurrent bladder cancer was investigated. We encountered 7 cases of which intravesical recurrent bladder cancer was found to occur in 5 cases. The involvement of the lymph node was found in one case and recurrence in intrapelvic cavity was observed in another case after total cystectomy. As a treatment method, thermotherapy was applied for the above 5 cases between 2 and 7 times in conjunction with an intrabladder injection of hydroxy propyl cellulose-adriamycin following M-VAC treatment for one case; the combined use of OK 432 and 5Fu was administered for another case together with thermotherapy applied 4 to 5 times, respectively. Results; Three of the above 5 cases were found to be CR including 2 cases of PR. One case was MR with another case of NC. Shrinkage of the tumor by more than 50% was recognized in one case of NC after five months.

Adult↗
PubMed1989

Location of forelimb motoneurons in the Japanese toad (Bufo japonicus): a horseradish peroxidase study.

To label the spinal motoneurons innervating the forelimb muscles of the Japanese toad, horseradish peroxidase (HRP) was injected into these muscles or applied to the cut end of the brachial nerves (N. radialis and N. ulnaris). Spatial distribution of the HRP-labeled motoneurons was reconstructed from serial frontal sections of the spinal cord and their location was examined. Motoneurons innervating forelimb muscles were distributed in the lateral cell column from segment 3 to segment 5 of the ipsilateral brachial spinal cord. In the transverse plane of the spinal cord, motoneurons innervating the medial forearm muscles (innervated by N. ulnaris) were located in the more medial part of the lateral cell column, whereas those innervating the lateral forearm muscles and the upper arm muscle (innervated by N. radialis) were located in the more lateral part of the lateral cell column. Along the longitudinal axis of the spinal cord, motoneurons innervating the more anterior (flexor side) forearm muscles were located in the more rostral part of the spinal cord, whereas those innervating the more posterior (extensor side) forearm muscles were located in the more caudal part of the spinal cord. Thus, motoneurons innervating forearm muscles were well organized somatotopically not only in the transverse plane, but also along the longitudinal axis of the spinal cord. Such a somatotopic organization of motoneurons along the longitudinal axis could also be regarded as a functional one; the flexor motoneurons were located rostrally to the extensor motoneurons.

Animals↗
PubMed1989

P-glycoprotein gene (MDR1) cDNA from human adrenal: normal P-glycoprotein carries Gly185 with an altered pattern of multidrug resistance.

We isolated a full-length MDR1 cDNA from human adrenal where P-glycoprotein is expressed at high level. The deduced amino acid sequence shows two amino acid differences from the sequence of P-glycoprotein obtained from colchicine-selected multidrug resistant cultured cells. The amino acid substitution Gly----Val at codon 185 in P-glycoprotein from colchicine resistant cells occurred during selection of cells in colchicine. As previously reported, cells transfected with the MDR1 cDNA carrying Val185 acquire increased resistance to colchicine compared to other drugs. The other amino acid substitution Ser----Ala at codon 893 probably reflects genetic polymorphism. The MDR1 gene, the major member of the P-glycoprotein gene family expressed in human adrenal, is sufficient to confer multidrug-resistance on culture cells.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1989

Cholescintigraphic observation of the sphincter of Oddi motor activity in patients with gallstone.

In 36 cases with gallstones, biliary scintigraphy was performed before and after operation to prepare the time-activity curve in the juxta-papillary duodenum. This curve showed different patterns depending on the conditions of disease, and seemed to represent on aspect of the sphincter of Oddi phasic activity, in view of the exerted effect of caerulein administration. This method is useful as a non-invasive one for the diagnosis of dynamic function of the sphincter of Oddi.

Ampulla of Vater↗
PubMed1989

Comparative study on metabolic formation of N-arylformamides and N-arylacetamides from carcinogenic arylamines in mammalian species.

The metabolism of carcinogenic arylamines was examined focusing on their N-acylation in mammalian species. When 4-aminobiphenyl, 2-aminonaphthalene, 2-aminofluorene, or 1-aminopyrene was given orally to rabbits, the corresponding N-arylformamides were isolated from the urine together with the corresponding N-arylacetamides. Identification of these N-arylformamides and N-arylacetamides was performed unequivocally by comparing their mass and UV spectra, and thin-layer chromatographic behaviors with those of authentic samples. Such metabolic conversion of the arylamines to the N-arylformamides and N-arylacetamides was also observed in guinea pigs and rats. In addition, carcinogenic nitro compounds such as 4-nitrobiphenyl and 2-nitronaphthalene, which are metabolically reducible to the arylamines, were metabolized to the corresponding N-arylformamides and N-arylacetamides in rabbits. On the other hand, quantitative experiments showed that only minor amounts of the N-arylformamides and N-arylacetamides were excreted in the urine or feces of rats and rabbits given the arylamines. This seems to be due to almost complete further metabolism of these N-acyl derivatives in vivo. Liver cytosols from several mammalian species exhibited a significant N-formylating activity toward the arylamines in the presence of N-formyl-L-kynurenine and N-acetylating activity in the presence of acetyl-CoA. In rabbits, the N-formylating activity was clearly higher than the N-acetylating activity, while the reverse was the case in guinea pigs and hamsters. The experiments with rat liver preparations showed that the liver cytosolic N-formylating and N-acetylating activities are due to formamidase and arylamine acetyltransferase, respectively. Furthermore, enzymatic transfer of the formyl group from one arylamine to another was demonstrated.

2-Naphthylamine↗
PubMed1989

Interaction of histones in glucocorticoid receptor binding to DNA in vitro.

We recently demonstrated that [1,2,4-3H]triamcinolone acetonide-receptor complexes purified 3000-fold from rat livers bound strongly to histone-agarose. The binding was not electrostatic, because it was not affected by ionic strength. In this in vitro study, we examined the effects of histones on the binding of glucocorticoid-receptor complexes to DNA-cellulose. The binding of the purified [1,2,4-3H]triamcinolone acetonide-receptor complexes to calf thymus DNA-cellulose was increased markedly in a dose-dependent manner by low concentrations of a whole histone mixture (H2A, H2B, H3, H4, and H1 from calf thymus), but this high level of binding decreased at higher concentrations of the histone mixture. The binding of receptor complexes to DNA-cellulose was enhanced greatly by histones H4 and H3 and slightly by histone H2A, was not affected by histone H2B, and was inhibited by histone H1. Similar stimulatory and inhibitory effects of these histones were seen when the DNA-cellulose was preincubated with the various histones and then washed to remove free histones before measurement of binding of the receptor complex. These results suggest that histones are involved in the mechanism of action of glucocorticoid hormones.

Animals↗
PubMed1989

Tongue-muscle-controlling motoneurons in the Japanese toad: neural inputs from the thalamus.

The anuran tongue is an effector organ specialized for snapping up prey during visually guided prey-catching behavior. As a step toward elucidating the control mechanisms of the tongue movement and overall organization of visually guided behavior, properties of neural inputs from the thalamus (of which electrical stimulation elicited a behavior very similar to the visually guided predator-avoidance behavior under freely behaving conditions) were investigated in paralyzed Japanese toads. Tongue-muscle-controlling motoneurons (tongue-protractor motoneurons (PMNs) and tongue-retractor motoneurons (RMNs)) were identified antidromically, and synaptic inputs in response to electrical stimuli applied to various points in the thalamus (mainly the posterocentral thalamic nucleus) were examined. Hyperpolarizing potentials were evoked in both PMNs and RMNs in response to single electrical stimuli applied to the thalamus contralateral or ipsilateral to the recording side. Since these potentials reversed to depolarizing ones after injecting Cl- ions into the cell interior, these hyperpolarizing potentials were concluded to be the usual fast type of inhibitory postsynaptic potentials (IPSPs). On the other hand, depolarizing potentials which were superimposed on the underlying IPSPs were evoked when repetitive electrical stimuli were applied to the thalamus. The amplitude of these depolarizing potentials was decreased when depolarizing currents were injected intracellularly, while it was increased when hyperpolarizing currents were injected, indicating that these depolarizing potentials are excitatory postsynaptic potentials (EPSPs).(ABSTRACT TRUNCATED AT 250 WORDS)

Action Potentials↗
PubMed1989

D-alanine as a chemical marker for the determination of streptococcal cell wall levels in mammalian tissues by gas chromatography/negative ion chemical ionization mass spectrometry.

A gas chromatography/mass spectrometry method using selected ion monitoring with negative ion detection and methane chemical ionization was employed to quantitate a marker for bacterial peptidoglycan, D-alanine, in mammalian tissues. D-Alanine originating from bacterial peptidoglycan was obscured by substantial amounts of D-alanine generated by racemization from L-alanine present in tissue protein. To overcome this problem, samples were enzymatically treated and hydrolyzed in deuterated hydrochloric acid. Newly formed D-alanine derived from protein was labeled with deuterium and bacterial D-alanine remained unlabeled, enabling differentiation by the molecular weight increase. Butyl heptafluorobutyryl derivatives of the D- and L-amino acids were separated on a fused silica capillary column coated with Chirasil-val. The amounts of bacterial D-alanine found in livers of arthritic rats were consistent with previously reported levels of other carbohydrate-derived markers for bacterial peptidoglycan-polysaccharide complexes.

Alanine↗
PubMed1989

Merkel cell carcinoma. A successful treatment with tumor necrosis factor.

A Merkel cell carcinoma of the mandibular area in a 78-year-old woman was treated successfully by direct intratumoral administration of recombinant human tumor necrosis factor. The patient received 2.5 x 10(5) U/d of recombinant human tumor necrosis factor every other day. A total of six injections (total dose, 1.5 x 10(6) U, 0.52 mg of protein) were administered over a period of 12 days. Soon after the therapy ended, the lesion softened and decreased in size. After 1 month, only erythema was visible. The lesion had completely disappeared clinically and histologically 5 months after the local injection of recombinant human tumor necrosis factor. Neither recurrence nor metastasis has been observed for at least 12 months following the treatment. Recombinant human tumor necrosis factor is suggested to be effective for the treatment of Merkel cell carcinoma.

Aged↗