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Biomedical subjects

T Mizuno

Publications and source records attributed to T Mizuno.

At least 91 records · Page 5Linked to original sources
PubMed2000

Analysis of aspartate aminotransferase in gingival crevicular fluid assessed by using PocketWatch: a longitudinal study with initial therapy.

AIM: The aim of this longitudinal study was to analyze the level of aspartate aminotransferase (AST) in gingival crevicular fluid (GCF) by using PocketWatch before and after initial therapy in patients with chronic adult periodontitis and to determine the relationship between AST and conventional measures of periodontal status, such as probing depth, clinical attachment level, bleeding on probing, and gingival index. METHOD: A total of 11 patients with chronic adult periodontitis were enrolled. Their periodontal status and AST levels in GCF were measured at baseline and post-initial therapy (the number of pockets=67), and statistically analyzed. RESULTS: There was a statistically significant difference in AST levels between diseased periodontal sites (1.2+/-0.7) and healthy sites (0.3+/-0.6, p<0.05), and between baseline and post-initial therapy (p<0.05). Improvements in clinical status were noted following periodontal therapy and there was a corresponding decrease in AST levels. CONCLUSIONS: In conclusion, it is suggested that AST levels may be a useful adjunct in the clinical assessment of periodontal disease sites, since AST level decreases when periodontal status improves.

Adult↗
PubMed2000

Tuning of the porin expression under anaerobic growth conditions by his-to-Asp cross-phosphorelay through both the EnvZ-osmosensor and ArcB-anaerosensor in Escherichia coli.

BACKGROUND: Widespread bacterial signal transduction circuits are generally referred to as 'two-component systems' or 'histidine (His)-to-aspartate (Asp) phosphorelays.' In Escherichia coli, as many as 30 distinct His-to-Asp phosphorelay signalling pathways operate in response to a wide variety of environmental stimuli, such as medium osmolarity and anaerobiosis. In this regard, it is of interest whether or not some of them together constitute a network of signalling pathways through a physiologically relevant mechanism (often referred to as 'cross-regulation'). We have addressed this issue, with special reference to the osmo-responsive EnvZ and anaero-responsive ArcB phosphorelay signalling pathways in E. coli. RESULTS: Under standard aerobic growth conditions, it is well known that the osmoregulatory profile of the outer membrane porins (OmpC and OmpF) is mainly regulated by the EnvZ-OmpR phosphorelay system in response to medium osmolarity. In this study, it was found that, under anaerobic growth conditions, E. coli cells exhibit a markedly altered expression profile of OmpC and OmpF This profile was significantly different from that observed for the cells grown aerobically. Results from extensive genetic studies showed that, under such anaerobic growth conditions, the arcB gene encoding the anaero-sensory His-kinase appears to be an auxiliary genetic determinant that regulates the expression profile of porins. We then provided several lines of in vivo and in vitro evidence, which taken together, supported the following conclusions. CONCLUSIONS: Under anaerobic growth conditions, porin expression is tuned not only by the authentic osmo-resposive EnvZ sensor, but also by the anaero-responsive ArcB sensor, in an OmpR-dependent manner. It is suggested that such ArcB-mediated cross-regulation plays a physiological role by integrating anaerobic respiratory signals into the porin regulation in E. coli anaerobiosis. The proposed model is a clear example of the interplay of two distinct His-to-Asp phosphorelay signalling pathways.

Anaerobiosis↗
PubMed2000

Complicating risk factors for pyelonephritis after extracorporeal shock wave lithotripsy.

PURPOSE: The score to predict the risk of post-extracorporeal shock wave lithotripsy (ESWL) pyelonephritis was evaluated. The score was based on the multivariate analysis of risk factors available pre-operatively. Stone size, pyuria, bacteriuria, previous pyelonephritis and other adjunctive procedures had been selected and scored. METHODS: Three-hundred and forty-eight adult patients without active urinary infection undergoing ESWL therapy were studied. One of three regimens were selected by either doctor or patient: (i) no antimicrobial treatment; (ii) one dose of levofloxacin; or (iii) 1 week course of levofloxacin. Who and why selected it were described. Post-ESWL fever over 38 degrees C was defined as the unfavorable event. RESULTS/CONCLUSION: With increasing score, doctors recommend taking an antimicrobial. There were 11 bacteriuric patients and post-ESWL pyelonephritis developed in one of them. Bacteria within the stone and post-ESWL ureteral obstruction caused by the stone fragments were considered to be important in developing pyelonephritis. However, multiple factors were related with it. Although their decision was not based simply on the score, the score was confirmed to be useful in identifying the high-risk patients and, therefore, to implement cost-effective antimicrobial use.

Adolescent↗
PubMed2000

Eradication of hepatitis C virus 1b by interferon in a health care worker with acute hepatitis following needlestick transmission from a patient with chronic hepatitis C unresponsive to interferon.

Hepatitis C virus (HCV) was successfully eradicated by a short course of interferon (IFN) therapy in a nurse with acute HCV infection from a needlestick accident. The source patient had chronic hepatitis C and was a nonresponder to IFN therapy. The HCV genotype was 1b in patients, and a single point mutation (H-->R in amino acid 2218) was observed in the IFN sensitivity-determining region of the nonstructural 5A gene, in comparison with sequences of HCV-J, in HCV RNA from both the source patient (before and after IFN therapy) and the recipient (before IFN therapy). Though the strain transmitted was believed to be IFN-resistant in the patient with chronic hepatitis, the patient with acute hepatitis had a sustained response.

Acute Disease↗
PubMed2000

Characterization of three putative sub-domains in the signal-input domain of the ArcB hybrid sensor in Escherichia coli(1).

The ArcB sensor plays a crucial role in the histidine to aspartate (His-to-Asp) phosphorelay signal transduction, which is involved in the transcriptional regulatory network that allows Escherichia coli cells to sense various respiratory growth conditions. ArcB is one of the best-studied hybrid His-kinases involved in the multi-step His-to-Asp phosphorelay. However, a major question that remains to be elucidated is: how does ArcB sense an anoxic signal? The N-terminal region of ArcB is considered to be a signal-input domain, which probably plays a role in such signal-perception. In this study, this N-terminal region of ArcB was dissected into three putative sub-domains, a "transmembrane domain," a "leucine-zipper-like domain, " and a "PAS-like domain." The importance of these structural domains was assessed in vivo and in vitro by systematically analyzing a number of arcB mutants, each of which encodes a mutant ArcB protein having an amino acid substitution or a deletion within one of these sub-domains. The results are discussed with special reference to the nature of the ArcB anaerobic sensor.

Amino Acid Sequence↗
PubMed2000

Genes encoding pseudo-response regulators: insight into His-to-Asp phosphorelay and circadian rhythm in Arabidopsis thaliana.

In the higher plant, Arabidopsis thaliana, results from recent intensive studies suggested that His-to-Asp phosphorelay mechanisms are involved presumably in propagation of environmental stimuli, such as phytohormones (e.g. ethylene and cytokinin). Here we identified and characterized a set of novel Arabidopsis genes whose products considerably resemble the authentic response regulators (ARR-series) of Arabidopsis in the sense that they have a phospho-accepting receiver-like domain. However, they should be discriminated from the classical ones in the strict sense that they lack the invariant phospho-accepting aspartate site. They were thus named APRRs (Arabidopsis pseudo-response regulators). Two such representatives, APRR1 and APRR2, were characterized extensively through cloning of the corresponding cDNAs, in terms of their structural designs, biochemical properties, subcellular localization in plant cells, and expression profiles at the transcriptional level. The result of in vitro phosphorylation experiment with the Arabidopsis AHP phosphotransmitter suggested that the pseudo-receivers have no ability to undergo phosphorylation. The result of transient expression assay with onion epidermal cells showed that the GFP-APRR1 fusion protein has an ability to enter into the nuclei. The C-terminal domain of APRR1, termed CONSTANS-motif, appears to be responsible for the nuclear-localization. The most intriguing result was that the accumulation of APRR1 transcript is subjected to a circadian rhythm. The APRR1 protein is identical to the one that was recently suggested to interact with the ABI3 (ABISCISIC ACID INSENSITIVE3) protein. These are discussed with special reference to the His-to-Asp phosphorelay signal transduction and circadian rhythm in Arabidopsis thaliana.

Amino Acid Sequence↗
PubMed2000

Circadian waves of expression of the APRR1/TOC1 family of pseudo-response regulators in Arabidopsis thaliana: insight into the plant circadian clock.

The Arabidopsis pseudo-response regulator, APRR1, has a unique structural design containing a pseudo-receiver domain and a C-terminal CONSTANS motif. This protein was originally characterized as a presumed component of the His-to-Asp phosphorelay systems in Arabidopsis thaliana. Recently, it was reported that APRR1 is identical to the TOC1 gene product, a mutational lesion of which affects the periods of many circadian rhythms in Arabidopsis plants. TOC1 is believed to be a component of the presumed circadian clock (or central oscillator). Based on these facts, in this study four more genes, each encoding a member of the APRR1/TOC1 family of pseudo-response regulators were identified and characterized with special reference to circadian rhythms. It was found that all these members of the APRR1/TOC1 family (APRR1, APRR3, APRR5, APRR7, and APRR9) are subjected to a circadian rhythm at the level of transcription. Furthermore, in a given 24 h period, the APRR-mRNAs started accumulating sequentially after dawn with 2-3 h intervals in the order of APRR9-->APRR7-->APRR5-->APRR3-->APRR1. These sequential events of transcription, termed 'circadian waves of APRR1/TOCI', were not significantly affected by the photoperiod conditions, if any (e.g. both long and short days), and the expression of APRR9 was first boosted always after dawn. Among these APRRs, in fact, only the expression of APRR9 was rapidly and transiently induced also by white light, whereas such light responses of others were very dull, if any. These results collectively support the view that these members of the APRR1/TOC1 family are together all involved in an as yet unknown mechanism underlying the Arabidopsis circadian clock. Here we propose that the circadian waves of the APRR1/TOC1 family members are most likely a molecular basis of such a biological clock in higher plants.

Amino Acid Sequence↗
PubMed2000

Spy1, a histidine-containing phosphotransfer signaling protein, regulates the fission yeast cell cycle through the Mcs4 response regulator.

Common histidine-to-aspartate (His-to-Asp) phosphorelay signaling systems involve three types of signaling components: a sensor His kinase, a response regulator, and a histidine-containing phosphotransfer (HPt) protein. In the fission yeast Schizosaccharomyces pombe, two response regulators, Mcs4 and Prr1, have been identified recently, and it was shown that they are involved in the signal transduction implicated in stress responses. Furthermore, Mcs4 appears to be involved in mitotic cell-cycle control. However, neither the HPt phosphotransmitter nor His kinase has been characterized in S. pombe. In this study, we identified a gene encoding an HPt phosphotransmitter, named Spy1 (S. pombe YPD1-like protein). The spy1(+) gene showed an ability to complement a mutational lesion of the Saccharomyces cerevisiae YPD1 gene, which is involved in an osmosensing signal transduction. The result from yeast two-hybrid analysis indicated that Spy1 interacts with Mcs4. To gain insight into the function of Spy1, a series of genetic analyses were conducted. The results provided evidence that Spy1, together with Mcs4, plays a role in regulation of the G(2)/M cell cycle progression. Spy1-deficient cells appear to be precocious in the entry to M phase. In the proposed model, Spy1 modulates Mcs4 in a negative manner, presumably through a direct His-to-Asp phosphorelay, operating upstream of the Sty1 mitogen-activated protein kinase cascade.

Amino Acid Sequence↗
PubMed2000

Role of hypothermia induced by tumor necrosis factor on apoptosis and function of inflammatory neutrophils in mice.

Changes in body temperature and cell infiltration, mediated by cytokines including tumor necrosis factor-alpha (TNF-alpha), occur during inflammation, but a role of body temperature on inflammatory responses remains obscure. Intraperitoneal injection of 10% casein to mice resulted in transient hypothermia followed by neutrophil accumulation in peritoneal cavities. Peritoneal TNF-alpha was rapidly raised, and pretreatment of mice with an anti-TNF-alpha antibody promoted temperature restoration and partially inhibited neutrophil accumulation. To investigate direct effects of body temperature on neutrophils, peritoneal or peripheral blood neutrophils were cultured at 35 degrees C or 37 degrees C with or without recombinant murine TNF-alpha (100 ng/ml) or a protein synthesis inhibitor cycloheximide (1 microg/ml). Significant inhibition of spontaneous and TNF-alpha-induced apoptosis was obtained at 35 degrees C compared with 37 degrees C, an effect that was not altered by the addition of cycloheximide. Moreover, phagocytic ability of peritoneal neutrophils was significantly enhanced by incubating them at the lower temperature. These results indicate that mild hypothermia induced by endogenous TNF-alpha has enhancing roles on neutrophil survival and function during peritoneal inflammation.

Animals↗
PubMed2000

Age-dependent change in the levels of Abeta40 and Abeta42 in cerebrospinal fluid from control subjects, and a decrease in the ratio of Abeta42 to Abeta40 level in cerebrospinal fluid from Alzheimer's disease patients.

In order to address an age-dependent alteration in the concentration of beta-amyloid polypeptides (Abetas) within the central nervous system and its probable predisposition to amyloidgenesis in Alzheimer's disease (AD), we measured two species of soluble Abetas, Abeta40 and Abeta42, in cerebrospinal fluids (CSF) from randomly selected Japanese control subjects at various ages (n = 33) and then compared these data with those of probable Japanese AD patients (n = 23). CSF concentrations of Abeta40 and Abeta42 peptides were age-dependent (ANOVA, Bonferroni's multiple comparison; p < 0.01 and p < 0.05, respectively) and were lower in the infant than in adults. From mid-20, the Abeta40 concentrations were decreasing while Abeta42 were rather stable. Abetas in CSF from AD patients (n = 23), whose epsilon4 allele frequency of the apolipoprotein E gene was higher than in controls (n = 83, p < 0.03), were not statistically different from those of age-matched controls (n = 13). A linear relationship was detected between the Abeta40 concentration and the Mini-Mental State Examination score (p < 0.05). The ratio of the Abeta42 to the Abeta40 level measured in the AD CSF samples was approximately 38% decreased compared to age-matched controls (p < 0. 05). These data suggest that the physiological metabolism of soluble Abetas in the brain is regulated in an age-dependent manner, and that the ratio of Abeta42 to Abeta40 level in the CSF would be a useful marker for monitoring progression of AD.

Adult↗
PubMed2000

Age-dependent decline in the apolipoprotein E level in cerebrospinal fluid from control subjects and its increase in cerebrospinal fluid from patients with Alzheimer's disease.

In order to address the significance of apolipoprotein E (apoE) in the pathogenesis as well as the clinical diagnosis of Alzheimer's disease (AD), we measured its level in cerebrospinal fluid (CSF) from randomly selected Japanese control subjects at various ages (n = 36), which included 14 age-matched controls, and from AD patients including early-onset (n = 11, EOAD) and late-onset (n = 14, LOAD) cases. The CSF apoE level in controls linearly decreased during aging to over 80 years (r(2) = 0.323, p < 0.0001). The CSF apoE level in AD patients was 31.9% elevated compared to the age-matched controls (n = 14, p < 0.05) and linearly increased with a decrement of the patients' Mini Mental State Examination scores. Moreover, the CSF apoE level of EOAD patients (n = 11) was higher than that of LOAD patients (n = 14, p < 0.05), whose APOE epsilon4 allele frequency was significantly higher than that of controls (chi(2) = 7. 16, p < 0.03). Two-dimensional gel electrophoretic analysis of the heparin-Mn(2+)-precipitable lipoprotein fraction in CSFs showed that the ratio between the level of CSF apoA-I and that of CSF apoE of controls was significantly higher than those of all AD and LOAD subjects (p < 0.01, p < 0.05), while the CSF apoA-I-to-apoE ratios of the two AD groups were not significantly different. These results suggest that overproduction of apoE protein may be a consequence of astroglial response to neurodegeneration in AD and that the determination of CSF apoliprotein levels serves as a clinical marker for monitoring the progression of AD.

Adolescent↗
PubMed2000

Microcatheter intrathecal urokinase infusion into cisterna magna for prevention of cerebral vasospasm: preliminary report.

BACKGROUND AND PURPOSE: The feasibility of preventing vasospasm by intrathecal anterograde infusion of urokinase (UK) into the cisterna magna was studied in patients with recently ruptured aneurysms who had just undergone the placement of a Guglielmi detachable coil (GDC). METHODS: Immediately after complete embolization with the use of GDC-10 coils, 15 patients with Hunt and Hess neurological grades III and IV received 60 000 IU of UK in normal saline through a microcatheter advanced into the cisterna magna. UK infusion was repeated once or twice over a period of 2 to 3 days according to a decision based on CT evidence of a subarachnoid clot remaining in the cisterns. Before administering the last UK infusion, we obtained CT confirmation of almost complete clearance of clots in the basal cisterns. RESULTS: In all 15 patients, the microcatheter was advanced easily into the cisterna magna by use of the over-the-wire microcatheter technique. In 8 patients who received thrombolytic therapy within 24 hours of the ictus, there was almost complete clearance of the clot in the basal cisterns within 2 days of suffering the insult. When UK was injected at 24 to 48 hours after the insult, 7 patients manifested CT evidence of clearance at the latest 4 days after suffering the insult. In all 15 patients, CT scans obtained within 24 hours of the final UK administration showed complete resolution of clots in the basal cistern and almost complete resolution of clots in the basal interhemispheric fissure and bilateral proximal sylvian fissures. Although one patient developed a transient neurological deficit, no patients manifested permanent delayed neurological deficits as a result of vasospasm. Outcome assessment according to the Glasgow Outcome Scale, no less than 3 months after GDC placement, revealed good recovery in all patients, and none developed hydrocephalus requiring a shunt procedure. CONCLUSIONS: In patients with recently ruptured aneurysms, GDC placement followed by immediate intrathecal administration of UK from the cisterna magna may be a safe and reasonable means of preventing vasospasms and may result in improved treatment outcomes.

Adult↗
PubMed2000

Identification and characterization of a novel gene, hos3+, the function of which is necessary for growth under high osmotic stress in fission yeast.

hos3 mutants of the fission yeast Schizosaccharomyces pombe showed the phenotype of high osmolarity sensitivity for growth. An S. pombe strain carrying the hos3-M26 allele cannot form colonies on agar plates containing 2 M glucose, but the parental strain can do so very well, as demonstrated previously. The hos3+ gene was cloned and identified as one that encodes a small protein of 94 amino acids, which shows no sequence similarity to any other proteins in the current databases. A hos3delta strain, which we then constructed, had the phenotype of high osmolarity sensitivity, as in the case of the original hos3-M26 mutant. More interestingly, when these hos- cells were grown in the non-permissive growth condition in the presence of 2 M glucose, we found that unusually many septated cells were accumulated after a prolonged incubation. A multicopy suppressor gene for hos- mutations was also isolated and identified as the dsk1+ gene encoding a protein kinase, which was previously suggested to be implicated in a process of the mitotic regulation of S. pombe. The function of the hos3+ gene is discussed from these results.

Cloning, Molecular↗
PubMed2000

Compilation and characterization of histidine-containing phosphotransmitters implicated in His-to-Asp phosphorelay in plants: AHP signal transducers of Arabidopsis thaliana.

Histidine (His)-to-Aspartate (Asp) phosphorelay signal transduction systems are generally made up of a "sensor histidine (His)-kinase", a "response regulator", and a "histidine-containing phosphotransmitter (HPt)". In the higher plant, Arabidopsis thaliana, results from recent intensive studies suggested that the His-to-Asp phosphorelay mechanism is at least partly responsible for propagation of environmental stimuli, such as phytohormones (e.g. ethylene and cytokinin). Here we compiled the members of the HPt family of phosphotransmitters in Arabidopsis thaliana (AHP-series, Arabidopsis HPt phosphotransmitters), based on both database and experimental analyses, in order to provide a comprehensive basis at the molecular level for understanding the function of the AHP phosphotransmitters that are implicated in the His-to-Asp phosphorelay of higher plants.

Amino Acid Sequence↗
PubMed2000

Identification and characterization of a novel gene, hos2+, the function of which is necessary for growth under high osmotic stress in fission yeast.

hos2 mutants of the fission yeast Schizosaccharomyces pombe showed the phenotype of high osmolarity sensitivity for growth. An S. pombe strain carrying the hos2-M10 allele cannot form colonies on agar plates containing 2 M glucose, but the parental strain can do so very well, as demonstrated previously. In this study, the hos2+ gene was identified as one that encodes a small protein of 94 amino acids, which shows no sequence similarity to any other proteins in the current databases. The hos2-M10 mutation resulted in Gln-62 to TAG-termination codon. A Hos2-defective (hos2delta) strain, which we then constructed, showed the phenotype of high osmolarity sensitivity, as in the case of the original hos2-M10 mutant. For this hos2delta mutant, three multicopy suppressor genes were isolated and one of which was identified as the pgk1+ gene, encoding a phosphoglycerate kinase.

Amino Acid Sequence↗
PubMed2000

Deletion of the yhhP gene results in filamentous cell morphology in Escherichia coli.

The Escherichia coli yhhP gene was predicted to encode a small hypothetical protein of 81 amino acids, the cellular function of which is not known. To gain insight into the function of this uncharacterized YhhP protein, genetic and biochemical studies were done. We first tried to express and purify the YhhP protein to prepare an anti-YhhP antiserum. Western blotting showed that the hypothetical yhhP gene is indeed transcribed and translated as a minor cytoplasmic protein. YhhP-deficient (delta yhhP) cells formed colonies poorly on a rich medium (e.g., Luria-Bertani medium) containing a relatively low concentration of NaCl, while they can grow normally either in LB containing 3% NaCl or in a synthetic medium (e.g., M9-glucose). During exponential growth in rich medium, an early step of cell division was inhibited in delta yhhP cells, forming filaments. For the YhhP-deficient filamentous cells, the FtsZ-ring formation was analyzed with immunofluorescence microscopy. The FtsZ-ring formation did not occur normally in the delta yhhP filaments, although the filamentous cells contained the FtsZ protein at a certain level comparable to that in the wild-type cells. The ftsZ gene was found to function as a multicopy suppressor of the delta yhhP mutant. Another multicopy suppressor gene was identified as the dksA gene. Provided that either the ftsZ or dksA gene was introduced into the mutant cells with its multicopy state, the resulting transformants were capable of growing in rich medium, formed wild-type short rods. These results are discussed with regard to the presumed function of this ubiquitous protein.

Amino Acid Sequence↗
PubMed2000

Clonality analysis of various hematopoietic disorders in cats naturally infected with feline leukemia virus.

The clonality analysis of the bone marrow cells was carried out by detecting the integrated proviruses of feline leukemia virus (FeLV) to understand the pathogenesis of FeLV-associated hematopoietic disorders in cats. Bone marrow cells from 4 cases with acute myeloid leukemia (AML), 9 cases with myelodysplastic syndromes (MDS), 2 cases with pure red cell aplasia (PRCA) and 3 healthy carriers infected with FeLV were subjected to Southern blot analyses using an exogenous FeLV probe. Clonal hematopoiesis was found in all the cases with AML and in 6 of the 9 cases with MDS, but not in the cases with both PRCA and healthy carriers infected with FeLV. In the 2 cases with MDS, it was thought that the same clones of the hematopoietic cells might proliferate before and after the progression of the disease irrespective of the changes of the hematological diagnoses by cytological examination. This study indicates that MDS in cats is a disease manifestation as a result of clonal proliferation of hematopoietic cells and can be recognized as a pre-leukemic state of AML.

Animals↗