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Biomedical subjects

K Tsuchiya

Publications and source records attributed to K Tsuchiya.

At least 19 recordsLinked to original sources
PubMed1992

DNA cleavage by hydroxyl radicals generated in a vanadyl ion-hydrogen peroxide system.

Vanadyl ion (+4 oxidation state) has been shown to be an effective agent for chemoprotection of cancers in animals. For understanding the mechanism, distribution of vanadium was studied. More vanadium was found to accumulate in the nuclei of the liver of rats when it was given as vanadyl sulfate than when it was given as sodium vanadate (+5 oxidation state). The reactivity of vanadyl ion with DNA was investigated by the DNA cleavage technique and the reaction mechanism by ESR spectroscopy. Incubation of double-strand DNA with vanadyl ion and hydrogen peroxide resulted in marked concentration- and pH-dependent DNA cleavage. Studies by the ESR spin-trap method demonstrated that hydroxyl radicals are generated during the reactions of vanadyl ion with hydrogen peroxide. Thus the antineoplastic action of vanadyl ion is proposed to be due to DNA cleavage by hydroxyl radicals generated in the cells.

Animals↗
PubMed1992

ATP is a coupling modulator of parallel Na,K-ATPase-K-channel activity in the renal proximal tubule.

A fundamental and essential property of nearly all salt-transporting epithelia is the tight parallel coupling between the magnitude of the K-conductive pathway at the basolateral membrane and the activity of the Na,K-dependent ATPase (Na,K-ATPase). In the present study, we demonstrate that the coupling response in the renal proximal tubule is governed, at least in part, through the interaction between ATP-sensitive K channels and Na,K-ATPase-mediated changes in intracellular ATP levels. First, we identified a K-selective channel at the basolateral membrane, which is inhibited by the cytosolic addition of ATP. Second, conventional microelectrode analysis in the isolated perfused proximal straight tubule revealed that these channels are the major determinant of the macroscopic K conductance so that ATP-mediated changes in the open probability of the K channel could alter the extent of K recycling. Indeed, the increase in the macroscopic K conductance upon stimulation of transcellular Na transport and pump activity was found to be paralleled by a decrease in intracellular ATP. Finally, a causal link between parallel Na,K-ATPase-K-channel activity and ATP was established by the finding that intracellular ATP loading uncoupled the response. With our recent observations that similar ATP-sensitive K channels are expressed abundantly in other epithelia, we postulate that ATP may act as a universal coupling modulator of parallel Na,K-ATPase-K-channel activity.

Adenosine Triphosphate↗
PubMed1992

The discovery of the causal agent of Minamata disease.

After the outbreak of an epidemic of a strange disease characterized by severe neurological signs in the small Japanese town of Minamata, a number of scientists in different disciplines were required to identify the causal agent. An account is given of the three-year program, with its disappointments and frustrations as a result of the limitations of knowledge of ecological principles and the absence of adequate techniques for detection and measurement. The lessons that have been learned on how toxic compounds can accumulate and concentrate in food chains are described as are the ecological contributions of environmentally safe waste disposal techniques. This article is based on the recollections of Dr. Shoji Kitamura, who contributed greatly to the discovery of the causative agent of Minamata disease.

Animals↗
PubMed1992

High level expression of the synthetic human lysozyme gene in Aspergillus oryzae.

Aspergillus oryzae was transformed with a synthetic gene consisting of a chicken lysozyme signal sequence and a mature human lysozyme (HLY) sequence. The transformants secreted active HLY (about 1.2 mg/l) when the HLY gene was expressed under the control of the Taka-amylase A gene (amyB) promoter. Western blot analysis suggested that the secreted protein was immunoreactive with anti-human lysozyme antibody and the signal peptide was correctly cleavaged off in the A. oryzae transformants. The transcriptional level of the HLY gene was investigated by Northern blot analysis using a probe that was equivalently specific to both the HLY gene and the amyB gene. The HLY gene was expressed at a higher level compared with the amyB gene because of its multi-copy integration. The efficient transcription of the HLY gene suggested that A. oryzae is a promising host for production of heterologous proteins from higher eukaryotes.

Amylases↗
PubMed1992

Contrast-enhanced magnetic resonance imaging of sub- and epidural empyemas.

Contrast-enhanced magnetic resonance images (MRI) of three patients with subdural (SDE) and two with epidural empyemas (EDE) were reviewed. In each case, the capsule of the lesion demonstrated enhancement, and distinction between capsule and contents was obvious on contrast-enhanced images. In SDE, contrast-enhanced images clearly depicted thickening of the neighbouring dura mater and a co-existent brain abscess. In EDE, part of the displaced dura mater did not enhance, which facilitated differentiation from SDE. Contrast-enhanced MRI was thus of value in diagnosis.

Adolescent↗
PubMed1992

Millardia meltada, a new host for Acanthocheilonema viteae and a simple technique for separation of microfilariae from peripheral blood.

Millardia meltada were infected with Acanthocheilonema viteae and examined for their susceptibility. The morbidity of infected M. meltada was low compared with that of jirds. On day 47 post-infection (p.i.), 13 of 14 M. meltada developed microfilaremia. Male M. meltada then showed gradually increasing microfilaremia with a peak level of 7000 per 30 microliters blood at week 20 p.i., which was much higher than that (3000) of male jirds. In contrast, microfilarial densities of female M. meltada were markedly low with a peak level of 200 during weeks 10-12 p.i. A simple centrifugation technique with Lympholyte-M was devised for microfilarial separation from the peripheral blood of infected M. meltada and yielded approximately 17 x 10(5) viable microfilariae from 1 ml of blood. This method also makes it possible to collect microfilariae from the same individuals repeatedly. M. meltada, coupled with this microfilarial separation technique, serves as a useful animal model for microfilarial studies of A. viteae.

Animals↗
PubMed1992

Intravascular foreign bodies: loop-snare retrieval system with a three-lumen catheter.

A foreign body retrieval system composed of a three-lumen catheter, a guide wire, and a wire loop nearly perpendicular to the axis of the catheter was used to retrieve catheter fragments located in the inferior vena cava in two patients and in the superior vena cava in one patient. Fragments were looped within 1 minute of catheterization and were retrieved without complication. Catheter fragments placed in the pulmonary artery of one dog were also successfully retrieved.

Animals↗
PubMed1992

Guide-wire-directed detachable balloon: clinical application in treatment of varicoceles.

Wire-directed detachable balloons were used in embolization treatment of varicoceles in six patients. Advancement of the balloon over a guide wire allowed easy embolization of the internal spermatic vein at the level of the inguinal ring. Additional detachable balloons were used to occlude the collateral vessels to the varicocele. This method proved highly effective in embolization of tortuous veins and in placement of multiple balloons.

Adolescent↗
PubMed1992

Further observations on serial serum immunoreactive inhibin levels in the luteal phase and early gestation after ovarian stimulation for in vitro fertilization and embryo transfer.

Serum immunoreactive inhibin of the luteal phase was measured by radioimmunoassay in 71 patients in vitro fertilization and embryo transfer (IVF-ET). The correlation between the pregnancy outcome and the serial inhibin pattern from the luteal phase to early gestation was studied. In nonconception cycles (n = 35), serum inhibin concentration rose and reached a peak level around 5 or 6 days after oocyte pick-up (OPU), then fell to the level of the early follicular phase. In conception cycles (n = 22), serum inhibin levels rose again 10-15 days after OPU. Serum inhibin levels were significantly higher from 10 days after OPU in multiple pregnancy (n = 5) than in single pregnancy (n = 17). In viable single pregnancy (n = 17), serum inhibin levels were significantly higher than in non-viable pregnancy (n = 14) from 15 days after OPU. Serum inhibin levels in early gestation correlated well with the pregnancy outcome of IVF-ET. These data suggest that inhibin is an important factor for the diagnosis of pregnancy outcome.

Abortion, Spontaneous↗
PubMed1992

Indonesian medicinal plants. II. Chemical structures of Pongapinones A and B, two new phenylpropanoids from the bark of Pongamia pinnata (Papilionaceae).

Two new phenylpropanoids named pongapinone A (1) and pongapinone B (2) were isolated from the bark of Pongamia pinnata (Papilionaceae), an Indonesian medicinal plant, and their chemical structures have been elucidated on the basis of their physicochemical properties. Pongapinone A (1) was found to inhibit interleukin-1 production.

Chromones↗
PubMed1992

Deletion analysis of the Taka-amylase A gene promoter using a homologous transformation system in Aspergillus oryzae.

The Taka-amylase A gene (amyB) of Aspergillus oryzae is induced by starch or maltose. The molecular mechanism of the induction was investigated using a fusion of the amyB promoter and the Escherichia coli uidA gene encoding beta-glucuronidase (GUS). To identify the region responsible for high-level expression and regulation within the amyB promoter, a series of deletion promoters was constructed and introduced into the A. oryzae met locus by homologous recombination. Deletion of the region between -377 to -290 (the number indicates the distance in base pairs from the translation initiation point (+1) to the deletion end point) significantly reduced of the GUS activity, but slight reduction of the GUS activity was observed in deletions up to -377. Northern blot analysis showed that reduction of the GUS activity depended upon the expression level of the GUS gene. The region between -377 to -290 is suggested to include the sequence required directly for high-level expression and regulation of the amyB gene.

Aspergillus oryzae↗
PubMed1992

Purification and characterization of a thermostable alkaline protease from alkalophilic Thermoactinomyces sp. HS682.

Protease secreted into the culture medium by alkalophilic Thermoactinomyces sp. HS682 was purified to an electrophoretically homogeneous state through only two chromatographies using Butyl-Toyopearl 650M and SP-Toyopearl 650S columns. The purified enzyme has an apparent relative molecular mass of 25,000 according to gel filtration on a Sephadex G-75 column and SDS-PAGE and an isoelectric point above 11.0. Its proteolytic activity was inhibited by active-site inhibitors of serine protease, DFP and PMSF, and metal ions, Cu2+ and Hg2+. The enzyme was stable toward some detergents, sodium perborate, sodium triphosphate, sodium-n-dodecylbenzenesulfonate, and sodium dodecyl sulfate, at a concentration of 0.1% and pH 11.5 and 37 degrees C for 60 min. The optimum pH was pH 11.5-13.0 at 37 degrees C and the optimum temperature was 70 degrees C at pH 11.5. Calcium divalent cation raised the pH and heat stabilities of the enzyme. In the presence of 5 mM CaCl2, it showed maximum proteolytic activity at 80 degrees C and stability from pH 4-12.5 at 60 degrees C and below 75 degrees C at pH 11.5. The stabilization by Ca2+ was observed in secondary conformation deduced from the circular dichroic spectrum of the enzyme. The protease hydrolyzed the ester bond of benzoyl leucine ester well. The amino acid terminal sequence of the enzyme showed high homology with those of microbial serine protease, although alanine of the NH2-terminal amino acid was deleted.

Amino Acid Sequence↗
PubMed1992

[Prognostic value of urinary cytology in bladder tumor].

Retrospective analysis was carried out to evaluate the prognostic value of urinary cytology in bladder tumor patients. All of the 170 patients (107 superficial (less than T2), 60 advanced (greater than T1) and 3 unknown (TX)), who were followed after their first occurrence, had histologically diagnosed transitional cell tumors. Recurrence rate for superficial cases was higher (p less than 0.05) when urinary cytology, either before or after the initial treatment, was positive than when negative. Patients with positive urinary cytology before the initial treatment proved to show poor prognosis compared to those with negative cytology (p less than 0.01), and many of the positive cases were with advanced cancer. Urinary cytology seemed to be indicative of the neoplastic potential of bladder tumor.

Adult↗
PubMed1992

Isolation of spotted fever group rickettsia from Apodemus speciosus in an endemic area in Japan.

A spotted fever group rickettsia was isolated from Apodemus mice captured near the site where a person had been infected in Miyazaki Prefecture. Antigenic characteristics of the isolate designated as strain TO-1 were compared with those of Rickettsia japonica (strain YH) and Rickettsia montana (ATCC VR611) by the indirect fluorescent antibody test with 14 serum specimens obtained from Apodemus speciosus, immune rat antisera against the strains TO-1 and YH, and three patients' sera. The titers of these sera measured with strain TO-1 were identical to those with strain YH, suggesting the antigenic similarity between these two organisms. It was also suggested that Apodemus speciosus is likely to be an important vertebrate host for a spotted fever group rickettsia in Japan.

Animals↗
PubMed1992

[Benign brainstem encephalopathy with truncal ataxia--a clinical study of 3 cases].

Three cases (case 1, female, aged 30; case 2, male, aged 32; case 3, male, aged 34) of benign brainstem encephalopathy with truncal ataxia were reported. Two patients had prodromal symptoms Neurological examination revealed truncal ataxia in all cases. As additional neurological signs, anisocoria, mydriasis, nystagmus, ptosis, transient opsoclonus, and facial palsy were seen. There was neither drowsiness nor myoclonus in the three cases. On laboratory examinations, cold agglutination test revealed significant elevation in two cases. The examination of cerebrospinal fluid showed a moderate rise of proteins in one case, but did not revealed pleocytosis in any of the cases. Magnetic resonance imaging of one patient revealed an area of high intensity in the left pontine tegmentum by T2-weighed imaging. The prognosis for all these cases was good, and the reappearance of neurological signs was not present until now. Our cases were different from brainstem encephalitis (Bickerstaff's encephalitis) because of an absence of disturbed consciousness and no pleocytosis in the cerebrospinal fluid. Our cases were also different from "myoclonus-opsoclonus syndrome" because of an absence of myoclonus. We discussed a possibility of a new clinical syndrome which we call "benign brainstem encephalopathy with truncal ataxia".

Adult↗
PubMed1992

[An autopsied case of Parkinson's disease manifesting Shy-Drager syndrome].

We report an autopsied case of Parkinson's disease manifesting Shy-Drager syndrome. At the age of 63 years, the patient noticed an onset of progressive orthostatic dizziness, which was followed by constipation, dysuria, and sexual impotence. When he was 66 years old, syncopal attack for a few minutes, tremor in the bilateral hands, and memory disturbance developed. On admission, his blood pressure was 142/72 mmHg in supine position, which fell to 58/42 mmHg on standing with appropriate increase of heart rate. Neurological examination revealed hallucination, memory disturbance, masked face, muscular rigidity, bradykinesia, mild postural tremor, and autonomic dysfunction including severe orthostatic hypotension, hypohydrosis, constipation, dysuria, and sexual impotence. Electroencephalogram showed diffuse slowing. Brain CT demonstrated absence of severe atrophy of the cerebellum, and brain stem. Pharmacological study revealed denervation hypersensitivity to the intravenously administrated noradrenaline. A diagnosis of Shy-Drager syndrome was made, and he was treated with anti parkinsonian drugs. However, no improvement was observed in his clinical symptoms. Seven months later, he died of pneumonia. Neuropathological examination revealed marked neuronal cell loss and gliosis in the substantia nigra and locus ceruleus. Lewy bodies were seen in those pigmented nuclei, dorsal vagal nucleus, hypothalamus and nucleus basalis of Meynert. No abnormality was found in the intermediolateral nucleus of the spinal cord. This is the first report on a Japanese patient who presented clinically Shy-Drager syndrome and pathologically typical Parkinson's disease. In this patient, from the pharmacological and pathological findings, sympathetic ganglia were supposed to be the responsible lesion for orthostatic hypotension.

Aged↗