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Biomedical subjects

A Kato

Publications and source records attributed to A Kato.

At least 415 records · Page 23Linked to original sources
PubMed1995

Microvascular disorder of the stria vascularis in endolymphatic hydrops.

To investigate the role of pathology of the stria vascularis in endolymphatic hydrops, the vascularity and atrophy of the stria were examined by histological observation in guinea pig temporal bones affected by experimental endolymphatic hydrops. Blood cell sludge and vasoconstriction accompanied by strial atrophy were observed in the coiled arteriole and capillary of the stria vascularis of the ear with endolymphatic hydrops after exposure to noise, suggesting the development of inner ear circulatory disturbance. Furthermore, these findings were observed around the upper turn of the cochlea. The effect of glycerol and difenidol hydrochloride on endolymphatic hydrops was also examined. Vasoconstriction and blood cell sludge disappeared following administration of these agents, accompanied by collapse. These findings suggest the possibility that the circulatory disturbance might be the cause of endolymphatic hydrops, followed by strial atrophy.

Animals↗
PubMed1995

The emergence of free radicals after acoustic trauma and strial blood flow.

The effect of acoustic trauma on cochlear strial circulation was investigated immunohistologically in the guinea pig. Kanamycin was used as a tracer of blood flow. Moreover, histochemical examinations were made to reveal the emergence of free radicals in the cochlea following acoustic trauma. At 5 min (5 min after intense sound exposure 120-125 dB SPL, 3 h) the blood flow in the stria vascularis was greatly diminished. At 2 h the strial blood flow started to recirculate and at 6 h it appeared to have returned to normal. Superoxide anion radicals (O2-) emerged along the luminal membrane of the marginal cells of the stria vascularis at 5 min. O2- disappeared at 30 min, but reappeared at 2 h. The cause of its emergence at 5 min was obscure. However, the strange phenomenon that O2- emerged again at 2 h seemed ascribable to the re-circulation of strial blood flow after sound exposure.

Animals↗
PubMed1995

[Psychological problem due to long-term organic solvent abuse].

Organic solvent abuse in adolescents has become a serious social problem. One of the reasons for this is the relationship to juvenile delinquency, and another is that it leads to various clinical symptoms including disturbance of consciousness, hallucinations, fantasia and apathy. In this study, using a health questionnaire that is composed of 33 psychiatric and 29 physical items and the Rorschach Test, we investigated these symptoms and the psychodynamics of personality respectively. The principal component analysis obtained for the health questionnaire extracted four factors as follows: 1) feelings of general fatigue and somatic symptoms, 2) feelings of guilt and self blame, 3) low self esteem and withdrawal adaptation, and 4) unreasonable anxiety and sleeping disturbance. The results of Rorschach Test supported the loss of libido, disability of reality testing and ego vulnerability in organic solvent abusers. This research strongly suggests that apathetic or depressive mood in chronic organic solvent abusers relates with loss of drive.

Adolescent↗
PubMed1995

[Amotivational syndrome of chronic organic solvent abusers--neuropsychological study].

It is conceivable that many of chronic organic solvent abusers have shown "Amotivational Syndrome" that is often seen in marijuana abuse. This syndrome revealed various psychiatric symptoms such as diminution of ambition, productivity and motivation. However, the pathogenesis of this syndrome is not elucidated. In present study, we examined 31 patients who showed amotivational syndrome (AS) induced by chronic organic solvents abuse, using neuropsychological battery including Benton Visual Retention Test (BVRT) and Bender Gestalt Test (BGT). In BVRT, there was a differences between AS and controls in the items of number of errors, omission, distortion and misplacement. In BGT, each Figure's score except I and VIII has changed and total score was 43.25 (vs control; 23.05), corresponding to 9-10 year old development in AS. These results suggest that organic solvent-induced AS is closely related with neurological and cognitive impairments in the central nervous system.

Adolescent↗
PubMed1995

[Smoking habits in chronic schizophrenics].

The smoking habits of 48 chronic schizophrenics who were inpatients of private psychiatric were examined. Subjects were divided into three groups; non-smokers, moderate smokers and heavy smokers, and tested by Fagerstrom's Tolerance Questionnaire (FTQ) as a tobacco dependence evaluation, and Bender Gestalt Test (BGT) and Benton Visual Retention Test (BVRT) as a neuropsychological battery. In addition, we used the Scales for the Assessment of Negative Symptoms (SANS) to evaluate the degree of schizophrenic negative symptoms, confirming the correlation between SANS score and the amount of nicotine intake or FTQ item. From the results of FTQ scores and their correlation with SANS scores, the amount of nicotine intake was significantly related to the severity of schizophrenic negative symptoms including affective blunting, poverty of thinking and attention impairment. BGT and BVRT showed disturbances in visual-motor gestalt function, and attention and memory, in chronic schizophrenics who smoked, especially in heavy smokers. These results suggest that smoking behavior in chronic schizophrenics might increase the individual vigilance against negative symptoms, from the perspective of self-medication.

Adult↗
PubMed1994

Polymannosylation to asparagine-19 in hen egg white lysozyme in yeast.

Complementary DNA encoding hen egg white lysozyme (HEWL) was subjected to site-directed mutagenesis to have the N-glycosylation signal sequence (Asn19-Tyr20-Thr21) by substituting Arg with Thr at position 21. The mutant lysozyme (R21T) was expressed in Saccharomyces cerevisiae carrying the yeast expression plasmid inserting the mutant HEWL cDNA. The mutant lysozyme was expressed in the glycosylated forms which are mainly a polymannosyl form with a small amount of oligomannosyl form. The polymannosyl lysozyme was susceptible to Endo H cleavage of the carbohydrate chain. The length of the polymannose chain was predicted to be approximately 340 residues/mol of lysozyme from carbohydrate analysis. According to the estimation with low-angle laser light scattering combined with HPLC, the average molecular weight of polymannosyl lysozyme was 75 kDa, which is consistent with the value obtained from the carbohydrate analysis. The size of polymannosyl lysozyme R21T is similar or somewhat larger than that of G49N reported previously. Thus, it was confirmed that the unusually large polymannose chain was attached to heterologous mutant lysozyme, regardless of the N-linked position, in yeast.

Acetylglucosamine↗
PubMed1994

Colocalization of prolyl endopeptidase and amyloid beta-peptide in brains of senescence-accelerated mouse.

Prolyl endopeptidase-like immunoreactivity (PEP-LI) was detected and compared with amyloid beta-peptide-like immunoreactivity (A beta-LI) in the brains of senescence-accelerated mouse (SAM). Granular structures of PEP-LI in the hippocampus appeared progressively, and age- and strain-dependently to form deposits which distributed morphologically similar and closely to those of A beta-LI. These results suggest that PEP has functional relevance to amyloidgenesis in brains of SAM.

Aging↗
PubMed1994

The rolC promoter of Agrobacterium rhizogenes Ri plasmid is activated by sucrose in transgenic tobacco plants.

The 5'-upstream region of the rolC gene of the Ri plasmid is expressed specifically in phloem cells of transgenic higher plants. In this study, we demonstrated that the rolC promoter is activated by sucrose in phloem cells of transgenic tobacco seedlings bearing rolC promoter-uidA chimeric fusion gene. Since the rolC promoter is not activated by sorbitol, sucrose metabolism rather than osmotic pressure exerted by the disaccharide may be responsible for induction. Thus, experiments using 5'-upstream deletion mutants, internal deletion mutants, and chimeric constructs with a heterologous promoter (-90 region of the cauliflower mosaic virus 35S promoter) were conducted to define the region of the rolC promoter involved in sucrose activation. The results indicated that a cis-acting sucrose responsive region of the rolC promoter is located between -135 and -94 bp with respect to the transcription initiation site. In phloem cells, high concentrations of sucrose are encountered owing to ongoing translocation of photosynthates from source to sink tissues. Therefore, sucrose as a signal molecule may regulate the phloem-specific expression of the rolC promoter.

Bacterial Proteins↗
PubMed1994

Cloning, amino acid sequence and tissue distribution of porcine thimet oligopeptidase. A comparison with soluble angiotensin-binding protein.

We have previously determined the amino acid sequence of porcine soluble angiotensin-binding protein (sABP) by cDNA cloning and sequencing. In this study, we have cloned a sABP homologue (PABH) from the same porcine cDNA libraries used for sABP cloning. PABH and sABP have 65% sequence identity. Sequence comparisons with other proteins revealed very high similarities between porcine PABH and rat thimet oligopeptidase (90%), and between porcine sABP and rabbit microsomal endopeptidase (93%). This suggests that PABH and thimet oligopeptidase are identical and that sABP and microsomal endopeptidase are also the same. Indeed, sABP was shown to have a peptidase activity that is sensitive to the metal-chelating agents EDTA and 1,10-phenanthroline; sABP was also sensitive to the thiol reagent p-chloromercuriphenylsulfonic acid. RNase-protection assays, using RNA preparations from various porcine tissues, indicated that thimet oligopeptidase mRNA is ubiquitously expressed whereas sABP mRNA is predominantly expressed in the liver, kidney and adrenal gland. This assay also revealed tissue-specific alternative splicing of the sABP-encoding message.

Amino Acid Sequence↗
PubMed1994

Enhanced bactericidal action of lysozyme to Escherichia coli by inserting a hydrophobic pentapeptide into its C terminus.

The mechanism of the enhanced bactericidal action to Escherichia coli of the lysozyme having a hydrophobic pentapeptide (Phe-Phe-Val-Ala-Pro) at its C terminus was investigated. The modified lysozyme, hydrophobic pentapeptide-fused lysozyme (HLz), was secreted in the culture medium from yeast harboring the expression plasmid, in which a synthetic DNA fragment encoding a hydrophobic pentapeptide was introduced to the 3'-end of the coding region of the lysozyme cDNA. Although CD analysis showed that HLZ was considerably different from wild-type lysozyme (WLz) in the secondary and tertiary structures, it retained 76% of the lytic activity of WLz. When E. coli cells were exposed to the WLz or HLz, the survival cells were significantly reduced only in the case of HLz. Periplasmic proteins from the HLz-treated cells were released to an extent similar to that from the WLz-treated cells, indicating that HLz has nearly the same action as WLz with respect to the disruption of the outer membrane and peptidoglycan. Experiments with E. coli phospholipid liposomes revealed that HLz dissipated the valinomycin-induced transmembrane electrochemical potential, but WLz did not. These results suggest that the enhanced bactericidal action of HLz to E. coli is due to disruption of the electrochemical potential of the inner membrane in cooperation with the inherent function of the lysozyme to the outer membrane and peptidoglycan.

Alkaline Phosphatase↗
PubMed1994

Molecular cloning of the breakpoint for 3q27 translocation in B-cell lymphomas and leukemias.

Reciprocal exchanges between chromosomal region 3q27 and three loci of the Ig genes have been reported in cases of B-cell type non-Hodgkin's lymphoma. We have cloned a region containing a breakpoint junction of 3q27 from a cell line established from a patient with Burkitt's lymphoma carrying t(3;22)(q27;q11). The region cloned was shown to contain an Ig lambda light chain gene fused to a gene on chromosome 3q27. This finding was subsequently confirmed by fluorescence in situ hybridization. Extra nucleotides were present at the joining site. The heptamer-like and nonamer-like sequences separated by an intervening 24 bp were present in the region corresponding to the breakpoint of 3q27, suggesting that a misrecombination in Ig gene rearrangement may be involved in the translocation. Southern blot analysis with a 3q27-specific probe showed rearrangements in three additional patients with B-cell malignancies with the t(3;14)(q27;q32). The breakpoints of all four cases clustered within a limited 3-kb region on chromosome 3q27. The region of 3q27 involved in the translocation was designated as the BCL5 locus. The transcripts from the BCL5 locus were detected in normal tissues and hematopoietic cell lines, and the increased expression of transcript of aberrant size was detected in the established cell line carrying t(3;22). These observations suggest that a gene located at 3q27 is involved in the translocation and that its deregulation plays a role in the malignant transformation of B cells.

Base Sequence↗
PubMed1994

Nucleotide sequence of a rice cDNA similar to a maize NADP-dependent malic enzyme.

We have isolated a rice cDNA clone that is homologous to the gene for the maize NADP-dependent malic enzyme (EC 1.1.1.40; NADP-ME). The deduced amino acid sequence coded for by the cDNA indicates a high level of homology to chloroplast type NADP-ME, including a transit peptide with pronounced hydrophobic properties at the amino terminus. Northern blot analysis indicates that the expression of this gene is regulated by external stress such as submergence.

Amino Acid Sequence↗
PubMed1994

Isolation and characterization of a rice cDNA similar to the S-phase-specific cyc07 gene.

We isolated a rice cDNA clone (T151) which encodes an open reading frame of 262 amino acids. This clone is similar to the S-phase-specific cyc07 gene of Catharanthus roseus. Expression of this gene is much higher in callus than in seedlings and regulated by external stresses such as high osmotic pressure, salinity, low temperature and submergence.

Amino Acid Sequence↗
PubMed1994

Complete regression of anaplastic astrocytoma by intravenous tumor necrosis factor-alpha (TNF alpha) after recurrence: a case report.

A 61-year-old male patient had a recurrence of anaplastic astrocytoma after initial chemoradiotherapy. After histologic confirmation of the recurrent tumor, he was treated with intravenous administration of human natural tumor necrosis factor-alpha (TNF alpha). Morphometric analysis of the tumor volumes demonstrated that the tumor continued to regress for 8 months during the course of intravenous TNF alpha therapy, and finally disappeared (total dose of intravenous TNF alpha, 785,000 JRU). The regression of tumor paralleled the neurologic improvement. He has had no signs of recurrence for 2 years. The present experience indicates that at least a certain population of malignant gliomas can be successfully treated by a systemic administration of TNF alpha without a major adverse effect.

Brain↗
PubMed1994

Effects of oxygen free radical scavengers on uranium-induced acute renal failure in rats.

Study was made to determine whether oxygen free radicals mediate uranium-induced acute renal failure (ARF). Superoxide dismutase (SOD), a superoxide anion scavenger, did not prevent uranium acetate (UA) (5 mg/kg, i.v.)-induced renal injury 48 h after injection. In contrast, dimethylthiourea (DMTU), a hydroxyl radical scavenger, significantly attenuated UA-induced rise in serum creatinine concentration (1.11 +/- 0.05 (DMTU) vs. 1.40 +/- 0.06 mg/dl (control), p < .05), and tubular necrosis. Dimethyl sulfoxide (DMSO), a hydroxyl radical scavenger, decreased UA-induced tubular damage. UA injection caused no increase in renal cortical malondialdehyde (MDA) content. DMTU and DMSO did not modify intrarenal MDA content. UA administration brought about significant increase in plasma renin activity but not in renal cortical renin content. Treatment with DMTU and DMSO had no effect on plasma renin activity or intrarenal renin content. It follows from these findings that DMTU and DMSO may attenuate UA-induced renal injury. Such a protective effect would not be mediated through modulation of lipid peroxidation or renin activity.

Acute Kidney Injury↗
PubMed1994

Metabolic pathway of 2-deoxy-2-[18F]fluoro-D-talose in mice: trapping in tissue after phosphorylation by galactokinase.

To make clear the metabolic fate of 2-deoxy-2-[18F]fluoro-D-talose ([18F]FDT) in animals, the in vivo and in vitro metabolism of non-radioactive 2-deoxy-2-fluoro-D-talose (FDT) was investigated by 19F-NMR spectroscopy. Based on the 19F-NMR spectral analyses, 2-deoxy-2-fluoro-alpha-D-talose-1-phosphate (FDT-1-P) was identified as a single metabolite in the organs of tumor-bearing mice after FDT administration (60 mg/kg). In the liver, almost all FDT was converted to FDT-1-P within 10 min after FDT injection and the phosphate form remained unchanged for at least 3 h. FDT was well converted to FDT-1-P by galactokinase in vitro. The FDT-1-P formed, however, failed to convert to a uridylate derivative by treatment with galactose-1-phosphate uridyltransferase. The observed low affinity of galactose-1-phosphate uridyltransferase for the FDT-1-P could account for the accumulation mechanism of FDT-1-P in vivo. Similar metabolic studies of [18F]FDT with radio-TLC demonstrated the [18F]FDT-1-P as a single metabolite of [18F]FDT in the mouse liver. These results indicate that [18F]FDT enters a D-galactose metabolic pathway and undergoes a metabolic trapping in the [18F]FDT-1-P form by galactokinase in the tissues such as liver and tumor. Consequently, [18F]FDT is expected to be a new radiopharmaceutical for the measurement of galactokinase activity by positron emission tomography.

Animals↗