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Biomedical subjects

A Watanabe

Publications and source records attributed to A Watanabe.

At least 235 records · Page 13Linked to original sources
PubMed1999

Tyrosine 265 of alanine racemase serves as a base abstracting alpha-hydrogen from L-alanine: the counterpart residue to lysine 39 specific to D-alanine.

Alanine racemase of Bacillus stearothermophilus has been proposed to catalyze alanine racemization by means of two catalytic bases: lysine 39 (K39) abstracting specifically the alpha-hydrogen of D-alanine and tyrosine 265 (Y265) playing the corresponding role for the antipode L-alanine. The role of K39 as indicated has already been verified [Watanabe, A., Kurokawa, Y., Yoshimura, T., Kurihara, T., Soda, K., and Esaki, N. (1999) J. Biol. Chem. 274, 4189-4194]. We here present evidence for the functioning of Y265 as the base catalyst specific to L-alanine. The Y265-->Ala mutant enzyme (Y265A), like Y265S and Y265F, was a poor catalyst for alanine racemization. However, Y265A and Y265S catalyzed transamination with D-alanine much more rapidly than the wild-type enzyme, and the bound coenzyme, pyridoxal 5'-phosphate (PLP), was converted to pyridoxamine 5'-phosphate (PMP). The rate of transamination catalyzed by Y265F was about 9% of that by the wild-type enzyme. However, Y265A, Y265S, and Y265F were similar in that L-alanine was inert as a substrate in transamination. The apo-form of the wild-type enzyme catalyzes the abstraction of tritium non-specifically from both (4'S)- and (4'R)-[4'-(3)H]PMP in the presence of pyruvate. In contrast, apo-Y265A abstracts tritium virtually from only the R-isomer. This indicates that the side-chain of Y265 abstracts the alpha-hydrogen of L-alanine and transfers it supra-facially to the pro-S position at C-4' of PMP. Y265 is the counterpart residue to K39 that transfers the alpha-hydrogen of D-alanine to the pro-R position of PMP.

Alanine↗
PubMed1999

AtUCP2: a novel isoform of the mitochondrial uncoupling protein of Arabidopsis thaliana.

Mitochondrial uncoupling proteins (UCPs) play a central role in adaptive thermogenesis in mammals. The UCPs dissipate the proton gradient formed through respiration without ATP synthesis, and the freed energy is readily converted to heat, helping the animals to maintain their body temperature in cold environments. Recently, it was found that UCPs also function in plant mitochondria. Subsequently, a cDNA clone encoding a UCP in potato was isolated. Whereas the UCP gene constitutes a multigene family in mammals, only a single cDNA sequence has been reported so far for the potato UCP. Moreover, it has been recently suggested that Arabidopsis has only a single nuclear gene for UCP. Here we report the existence of another UCP gene in the Arabidopsis genome, showing for the first time the occurrence of a multigene family for the protein in higher plants. A cDNA analysis of this gene showed that the novel isoform possesses all typical features reported for known UCPs. However, the new gene, unlike the other gene in Arabidopsis and the gene in potato, did not appear to respond to low temperature.

Amino Acid Sequence↗
PubMed1999

Identification of clp genes expressed in senescing Arabidopsis leaves.

Clp protease is a highly selective protease in E. coli, which consists of two types of subunits, the regulatory subunit with ATPase activity, ClpA, and the catalytic subunit, ClpP. In order to examine the possible association of plant Clp protease with the degradation of protein in senescing chloroplasts, we isolated a cDNA clone for ClpC which is a plant homologue of ClpA from Arabidopsis thaliana in addition to ERD1 which we had isolated earlier [Kiyosue et al. (1993) Biochem. Biophys. Res. Commun. 196: 1214]. We also isolated a clone for the plastidic gene, clpP (pclpP) and cDNA clones for putative nuclear clpP genes (nclpP1-6). We analyzed the expression of these clp genes in Arabidopsis leaves after various dark periods and during natural senescence. The expression of erd1 was increased by dark-induced and by natural senescence, as reported earlier [Nakashima et al. (1997) Plant J. 12: 851], while that of AtclpC was decreased. Two catalytic subunits nclpPs (nclpP3 and nclpP5) showed high expression in naturally senescing leaves, but the expression of pclpP and the other nclpPs was not changed. Immunoblot analysis of chloroplast protein and in vitro import analysis demonstrated that both nucleus-encoded regulatory subunits as well as nClpP5 were localized in the chloroplast stroma. These observations suggest that chloroplast Clp protease is composed of very complicated combinations of subunits, and that ERD1, nClpP5 and pClpP have a role in the concerted degradation of protein in senescing chloroplasts.

Adenosine Triphosphatases↗
PubMed1999

Usefulness of dual SPECT with Tc-99m pyrophosphate and Tl-201 to predict further events after acute myocardial infarction with single-vessel coronary artery disease.

PURPOSE: This study was undertaken to determine whether the findings of dual SPECT with Tc-99m pyrophosphate (PYP) and Tl-201 were predictive of further cardiac events after acute myocardial infarction. METHODS: The authors evaluated 88 patients with acute myocardial infarction who underwent dual SPECT for single-vessel coronary artery disease. RESULTS: Twenty-nine patients showed overlapping of Tc-99m PYP and Tl-201 in the same location (overlap-positive group), and 59 patients had no overlap (overlap-negative group). In patients in the overlap-positive group, the incidence of subsequent events was significantly higher than in patients in the overlap-negative group (P < 0.001). In the overlap-positive group, the number of overlap segments in patients with further events was significantly greater than that in patients without further events (P < 0.005). CONCLUSIONS: Areas with overlapping of Tc-99m PYP and Tl-201 may contain jeopardized myocardium. These results suggest that patients who have a Tc-99m PYP and Tl-201 overlap-negative scan are a low risk group, whereas patients who have more overlapping segments may require catheterization and revascularization. Thus simultaneous SPECT imaging with Tc-99m PYP and Tl-201 might be useful to identify patients with greater ischemic risk after acute myocardial infarction.

Aged↗
PubMed1999

Anchoring method for hemifacial spasm associated with vertebral artery: technical note.

OBJECTIVE: We describe an easy and useful method for treating hemifacial spasm related to the vertebral artery. METHODS: The technique entails the manufacture of a dural belt harvested from the cerebellar convexity dura and a dural bridge made at the petrous dura combined with the use of an aneurysm clip. The dural belt holds the vertebral artery and is anchored to the dural bridge by fixation with an aneurysm clip after the vertebral artery is transposed to an appropriate position. RESULTS: The technique proved to be safe and effective in a series of six patients with hemifacial spasm who were followed up for a period of 2 months to more than 10 years after surgery. All patients were affected on the left side. Multiple offending arteries were present in three cases. Hemifacial spasm completely disappeared in all patients. CONCLUSION: This method represents a feasible option for the treatment of hemifacial spasm caused by a tortuous, elongated, or enlarged vertebral artery.

Adult↗
PubMed1999

[Evaluation of mycobacteria growth indicator tube (MGIT), an automated culture system for detection of mycobacteria from clinical specimens].

We compared the Mycobacteria Growth Indicator Tube 960 (MGIT 960) and Ogawa medium (OM) for the detection of mycobacteria (acid fast bacteria: AFB) using 882 sputum specimens. Overall, 120 strains of AFB were isolated by the MGIT 960 system and 99 strains of AFB were isolated by using OM. As far as Mycobacterium tuberculosis is concerned, 88 and 71 isolates were achieved by the MGIT 960 and OM respectively. A total of 28 isolates (18 isolates of M. tuberculosis and 10 isolates of nontuberculous mycobacteria: NTM) were detected by the MGIT 960 only whereas only 2 isolates (1 M. tuberculosis and 1 NTM) were detected by OM only. Of these sputum specimens, 72 were smear positive for AFB. The rates of smear negative but culture positive specimens were 8.0% (65 out of 809) for the MGIT 960 system and 6.2% (50 out of 809) for OM. The contamination rate for MGIT 960 was only 1.2%. The average time required for detection of M. tuberculosis was 14.1 days by the MGIT 960 system and 24.6 days by OM. For the NTM, the average detection time were 8.3 days for the MGIT 960 system and 22.8 days for OM. These results indicate that the MGIT 960 system allows detection of mycobacteria significantly faster than OM.

Automation↗
PubMed1999

In vitro activity of HSR-903, a new oral quinolone, against bacteria causing respiratory infections.

The in vitro activity of HSR-903, an oral quinolone, against 196 recent clinical isolates of respiratory pathogens was evaluated. HSR-903 was 2 to 32 times more active than ofloxacin, ciprofloxacin, and sparfloxacin against Staphylococcus aureus, including methicillin-resistant strains, and Streptococcus pneumoniae and was at least as active as the other quinolones against gram-negative pathogens.

Anti-Infective Agents↗
PubMed1999

Eating problems and related weight control behaviour in adult Japanese women.

BACKGROUND: Fewer studies concerning eating problems have been conducted in adult than in adolescent female populations. The aims of this study are to ascertain the proportion of eating problems and clarify weight control behaviour in adult Japanese women. METHODS: This study employed a questionnaire survey with a cross-sectional design. Subjects were adult females aged 20-39 years, working in a computer factory. Four hundred and six women agreed to participate in the study. The questionnaire elicited self-reported age, body height, body weight and various histories of dieting, fasting and purging behaviour. The Eating Attitudes Test 26-item version (EAT-26) was also administered. Subjects showing an EAT-26 score equal to or greater than 20 were identified as having eating problems. RESULTS: Among the subjects, 172 women (42.4%) had some history of dieting behaviour and 24 (5.9%) had some history of fasting behaviour. Regarding misuse of laxatives, diet pills and diuretics for the purpose of weight loss, 50 (14.3%) were past or current users of diet pills, followed by 42 (10.3%) laxative abusers and 15 (3.7%) diuretic abusers. Six (1.5%) subjects had an EAT-26 score of 20 or greater, 5 (1.9%) in their 20s, and 1 (0.8%) in her 30s, the difference not being statistically significant. CONCLUSIONS: Although dieting behaviour is common in adult Japanese working women, the proportion of eating problems is low in comparison with Western adult populations.

Adult↗
PubMed1999

Role of transforming growth factor-beta 1 in invasion and metastasis in gastric carcinoma.

PURPOSE: Transforming growth factor-beta1 (TGF-beta1) is a major modulator of cellular proliferation and extracellular matrix formation. We determined the role of TGF-beta1 in invasion and metastasis in gastric cancer. MATERIALS AND METHODS: We detected TGF-beta1 expression in primary and lymph node metastatic lesions of gastric cancer, using an antibody and in situ hybridization. The plasma TGF-beta1 levels in the peripheral vein and in the tumor drainage vein were assayed. RESULTS: In the cytoplasm of cancer cells, TGF- beta1 was immunostained in 35.9% (78 of 217) of primary gastric carcinomas, and this expression was confirmed by in situ hybridization. Of 59 gastric carcinomas with a TGF-beta1-negative primary tumor, metastatic lymph nodes were positive for TGF-beta1 staining in 32 cases (54.2%). Positive staining of TGF-beta1 in gastric cancer tissues was closely related to serosal invasion, infiltrative growth, and lymph node metastasis. Multivariate analysis showed that the expression of TGF-beta1 was an independent risk factor for serosal invasion and infiltrative growth of the tumor. The plasma level of TGF-beta1 did not differ between TGF-beta1-negative and -positive groups. There were also no differences in plasma TGF-beta1 levels among each tumor stage, between the peripheral and the tumor drainage veins, and between preoperative and postoperative testings. CONCLUSION: Transforming growth factor-beta1 is closely related to the invasion and metastasis of gastric cancer, and production of TGF-beta1 in the tumor does not contribute to the total amount of TGF-beta1 in the blood circulation. We interpret our observations to mean that in a tumor microenvironment, TGF-beta1 alters the biologic behavior of the tumor.

Aged↗
PubMed1999

Depressive state with anxiety in repeated cold-stressed mice in forced swimming tests.

The effects of various types of stress and drugs were studied to assess mouse performance in forced swimming tests, following characterization of SART (specific alternation of rhythm in environmental temperature) stress. Immobility time in the test decreased in mice subjected to SART, acute cold and restraint stress. No change was noted due to chronic cold stress or repeated fasting. The shortened time did not recover even 24 hr after the end of SART and chronic restraint stress. The time in SART-stressed mice finally recovered at 5-7 days. Shortening of immobility time in SART-stressed mice was inhibited by diazepam and repeated imipramine but not by lithium carbonate. In chronic restraint-stressed mice, this time was inhibited by repeated lithium carbonate but not diazepam or imipramine. SART stress would thus appear related to anxiety and depression and may be useful for detecting new types of antidepressants.

Animals↗
PubMed1999

Heterologous expression and product identification of Colletotrichum lagenarium polyketide synthase encoded by the PKS1 gene involved in melanin biosynthesis.

The Colletotrichum lagenarium PKS1 gene was expressed in the heterologous fungal host, Aspergillus oryzae, under the starch-inducible alpha-amylase promoter to identify the direct product of polyketide synthase (PKS) encoded by the PKS1 gene. The main compound produced by an A. oryzae transformant was isolated and characterized to be 1,3,6,8-tetrahydroxynaphthalene (T4HN) as its tetraacetate. Since the PKS1 gene was cloned from C. lagenarium to complement the nonmelanizing albino mutant, T4HN was assumed to be an initial biosynthetic intermediate, and thus the product of the PKS reaction, but had not been isolated from the fungus. The production of T4HN by the PKS1 transformant unambiguously identified the gene to encode a PKS of pentaketide T4HN. In addition, tetraketide orsellinic acid and pentaketide isocoumarin were isolated, the latter being derived from a pentaketide monocyclic carboxylic acid, as by-products of the PKS1 PKS reaction. Production of the pentaketide carboxylic acid provided insights into the mechanism for the PKS1 polyketide synthase reaction to form T4HN.

Aspergillus oryzae↗
PubMed1999

Molecular cloning and ethylene-inducible expression of Chib1 chitinase from soybean (Glycine max (L.) Merr.).

A soybean seed-specific PR-8 chitinase, named Chib2, has a markedly extended C-terminal segment compared to other plant Chib1 homologues of the PR-8 chitinase family known to date. To further characterize the molecular structure and the expression pattern of this chitinase family, we cloned two typical Chib1-similar cDNAs (Chib1-1 and Chib1-2) from soybeans by PCR-cloning techniques. The deduced primary sequence of Chib1-1 chitinase is composed of a signal peptide segment (26 amino acid residues) and a mature 273 amino acid sequence (calculated molecular mass 28,794, calculated pI 3.7). This Chib1-1 enzyme is more than 90% identical to Chib1-2 chitinase but is below 50% identical to Chib2 enzyme. Thus, we confirmed the occurrence of two distinct classes, Chib1 and Chib2 in the plant PR-8 chitinase family. The Chib1 genes, interrupted by one intron, were found to be up-regulated in response to ethylene in stems and leaves, but scarcely expressed in developing soybean seeds. Chib1 chitinases may be responsible for protecting the plant body from various pathogenic attacks.

Amino Acid Sequence↗
PubMed1999

Effects of isoprothiolane on cell growth of cultured bovine mammary epithelial cells.

This study was performed to investigate the effects of isoprothiolane on cell growth and the production of interleukin (IL)-1 and IL-6 by bovine mammary epithelial cells in vitro. Isoprothiolane increased proliferation of mammary epithelial cells in a dose-dependent manner at the concentration of 0.05 to 5 microM when cultured either with or without serum-supplemented medium. In contrast, isoprothiolane (0.0005-5 microM) significantly inhibited the production of IL-1 and IL-6 by mammary epithelial cells. Moreover, the cytokines, IL-1alpha, IL-1beta, IL-6, and tumor necrosis factor (TNF)-alpha tended to inhibit the proliferation of mammary epithelial cells in a dose-dependent manner. These results indicated that isoprothiolane regulated mammary epithelial cell growth in vitro possibly by modulating the production of cytokines.

Animals↗
PubMed1999

Bronchiectasis with myeloperoxidase antineutrophil cytoplasmic antibody and bactericidal/permeability-increasing protein antineutrophil cytoplasmic antibody.

A 56-year-old woman was hospitalized for recurrent hemoptysis. She had been suffering from bronchiectasis for 4 years. Pseudomonas aeruginosa was persistently detected in her sputum. Serum was positive for Myeloperoxidase antineutrophil cytoplasmic antibody (MPO-ANCA) and bactericidal/permeability-increasing protein antineutrophil cytoplasmic antibody (BPI-ANCA). She underwent lung resection. Histopathologically, the resected lung showed bronchiectasis with pulmonary fibrosis but did not show vasculitis. Her serum became negative for the ANCAs after the operation. To date, she has no recurrence of hemoptysis. We discuss this case of bronchiectasis with MPO-ANCA and BPI-ANCA and suggest a possible role for ANCAs in chronic airway infection.

Antibodies, Antineutrophil Cytoplasmic↗
PubMed1999

Closed water recirculating system for fish rearing equipped with bioreactor capable of simultaneous nitrification and denitrification.

Five crucian carp, Carassius auratus langsdorfiicarps had been reared in a closed water recirculating system. The system was equipped with the compact bioreactor using the plate gels capable of both nitrification and denitrification in a single unit. Ammonia and nitrite concentrations in the rearing water had been maintained below 0.05 mg-N/L, and nitrate concentration also controlled between 2 and 8 mg-N/L with the bioreactor. As concerns nitrogen budget in the closed system, 95.0% of nitrogen income from feed was lost as nitrogen gas from the closed system. All fish was alive for 91 days without any unusual behavior. Thus, the bioreactor performed both nitrification and denitrification abilities enough to rear the five fish for 91 days. The bioreactor using the plate gels would be effective to simplify the closed system both physically and operationally, since it can remove the ammonia excreted from fish as nitrogen gas by a single step.

Ammonia↗
PubMed1999

Endosaccular aneurysm occlusion with Guglielmi detachable coils for obstructive hydrocephalus caused by a large basilar tip aneurysm. Case report.

The authors present the case of a 60-year-old man with obstructive hydrocephalus caused by a large basilar artery tip aneurysm, in whom direct surgical clipping of the aneurysm neck was considered hazardous. After endosaccular aneurysm occlusion, his symptoms (headache, intellectual impairment, and gait disturbance) and ventricular dilation immediately improved without placement of a ventricular shunt. To the authors' knowledge, this is the first case of its kind treated solely endovascularly.

Basilar Artery↗