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Biomedical subjects

Y Yamagata

Publications and source records attributed to Y Yamagata.

At least 19 recordsLinked to original sources
PubMed2006

Improvement of pulmonary function and dyspnea by tiotropium in COPD patients using a transdermal beta(2)-agonist.

BACKGROUND: A combination of bronchodilators may be effective in the treatment of chronic obstructive pulmonary disease (COPD). We examined the effect of adding a long-acting anti-cholinergic agent (tiotropium) to a transdermal-type beta(2)-agonist (tulobuterol) on dyspnea as well as pulmonary function. METHODS: In a multicentre, randomized, parallel design study, 60 COPD patients treated with the transdermal beta(2)-agonist tulobuterol were divided into a tiotropium added group (Tulo+Tio group, n=40) or transdermal beta(2)-agonist tulobuterol alone group (Tulo group, n=20), and then treated for 4 weeks after a 2 week run-in period. Pulmonary function and a dyspnea (Medical Research Council (MRC)) scale were assessed before and after the treatment. Daily peak expiratory flow (PEF) monitoring was also performed. RESULTS: After 4 weeks, the Tulo+Tio group showed a significant increase in pulmonary function compared with the Tulo group; DeltaFVC (0.31+/-0.06 L vs. 0.06+/-0.05 L, p< 0.01), DeltaFEV(1) (0.15+/-0.03 L vs. -0.02+/-0.02 L, p<0.0001), and DeltaPEF (41.0+/-5.1 L/min vs. 0.5+/-3.5 L/min, p<0.0001). The MRC dyspnea scale was also significantly improved in Tulo+Tio, but not in Tulo group. CONCLUSION: These results suggest that tiotropium caused a significant improvement in both pulmonary function and dyspnea in COPD patients already treated with the transdermal beta(2)-agonist tulobuterol.

Administration, Cutaneous↗
PubMed2006

A mechanism for the inactivation of Ca2+/calmodulin-dependent protein kinase II during prolonged seizure activity and its consequence after the recovery from seizure activity in rats in vivo.

Seizure is a form of excessive neuronal excitation and seizure-induced neuronal damage has profound effects on the prognosis of epilepsy. In various seizure models, the inactivation of Ca2+/calmodulin-dependent protein kinase II (CaMKII) occurs during seizure activity preceding neuronal cell death. CaMKII is a multifunctional protein kinase enriched in the brain and involved in various ways the regulation of neuronal activity. CaMKII inactivation during seizure activity may modify neuronal cell survival after seizure. However, the mechanism for CaMKII inactivation and its consequence after seizure recovery remain to be elucidated yet. In the present study, we employed a prolonged seizure model by systemic injection of kainic acid into rats and biochemically examined the activity state of CaMKII. In status epilepticus induced by kainic acid, not only the inactivation of CaMKII in brain homogenate, but also a shift in the distribution of CaMKII protein from the soluble to particulate fraction occurred in both hippocampus and parietal cortex. The particulate CaMKII showed a large decrease in the specific activity and a concurrent large increase in the autophosphorylation ratio at Thr-286 (alpha) and at Thr-287 (beta). In contrast, the soluble CaMKII showed normal or rather decreased specific activity and autophosphorylation ratio. After 24 h of recovery from kainic acid-induced status epilepticus, all such changes had disappeared. On the other hand, the total amount of CaMKII was decreased by 35% in hippocampus and 20% in parietal cortex, but the existing CaMKII was indistinguishable from those of controls in terms of the autonomous activity ratio, specific activity and autophosphorylation ratio. Thus, CaMKII inactivation in kainic acid-induced status epilepticus seems to be derived not from simple degradation of the enzyme, but from the formation of the autophosphorylated, inactivated and sedimentable CaMKII. Such a form of CaMKII may be important during pathological conditions in vivo in preventing excessive CaMKII activation due to Ca2+ overload.

Animals↗
PubMed2006

Inhibition of reactive nitrogen species production in COPD airways: comparison of inhaled corticosteroid and oral theophylline.

BACKGROUND: Reactive nitrogen species (RNS) are thought to be one of the important factors in the pathogenesis of chronic obstructive pulmonary disease (COPD). A study was undertaken to examine the effects of theophylline and fluticasone propionate (FP) on RNS production in subjects with COPD. METHODS: Sixteen COPD subjects participated in the study. Theophylline (400 mg/day orally) or FP (400 mug/day inhalation) were administered for 4 weeks in a randomised crossover manner with a washout period of 4 weeks. Induced sputum was collected at the beginning and end of each treatment period. 3-nitrotyrosine (3-NT), which is a footprint of RNS, was quantified by high performance liquid chromatography with an electrochemical detection method as well as by immunohistochemical staining. RESULTS: Theophylline significantly reduced the level of 3-NT in the sputum supernatant as well as the number of 3-NT positive cells (both p<0.01). FP also reduced 3-NT formation, but the effect was smaller than that of theophylline. Theophylline also significantly reduced the neutrophil cell counts in the sputum (p<0.01), while FP treatment had no effect on the number of inflammatory cells in the sputum, except eosinophils. CONCLUSIONS: Theophylline reduces nitrative stress and neutrophil infiltration in COPD airways to a larger extent than inhaled corticosteroid.

Administration, Inhalation↗
PubMed2005

Effect of the adenovirus E1A gene on nitric oxide production in alveolar epithelial cells.

This study determined the effect of the adenovirus E1A gene on nitric oxide (NO) production in alveolar epithelial (A549) cells. E1A-positive A549 cells (E1A transfectants), E1A-negative A549 cells (control transfectants) and untransfected A549 cells were placed in 96-well tissue culture plates. After stimulation with lipopolysaccharide (LPS) or cytokine mixture (CM), the biochemical reaction products of NO (nitrite and nitrate) in the culture medium were measured by chemiluminescence. The inducible (iNOS) and the endothelial (eNOS) isoforms of nitric oxide synthase (NOS) protein expression were examined by Western blotting. iNOS mRNA expression was examined by Northern blotting and RT-PCR. CM-induced NO production by E1A-positive A549 cells was significantly lower than that of E1A-negative cells (p < 0.0001). LPS stimulation failed to enhance NO production in both cell types. CM induced iNOS protein expression in E1A-negative A549 cells, but not in E1A-positive cells. eNOS protein expression was constitutive and was not affected by CM stimulation, LPS stimulation or E1A. CM induced iNOS mRNA expression in E1A-negative A549 cells, but not in E1A-positive cells. In conclusion, the adenovirus E1A gene suppressed NO production through transcriptional control of the iNOS gene in A549 cells. This inhibition of NO production may enable the virus to persist in human tissue, since NO is an antiviral effector of the innate immune system.

Adenovirus E1A Proteins↗
PubMed2005

Increased serum concentrations of tissue inhibitor of metalloproteinase-1 in COPD patients.

Matrix metalloproteinase (MMP)-9 and tissue inhibitors of metalloproteinase (TIMP)-1 concentrations are increased in the sputum of asthma and chronic bronchitis patients, and are thought to be related to airflow obstruction. However, serum concentrations of these enzymes have not been clearly evaluated in patients with chronic obstructive pulmonary disease (COPD). The aim of this study was to examine the serum concentrations of these enzymes in COPD and asthmatic patients in order to determine their relationship with airway obstruction. Serum samples were obtained from 72 patients with COPD: 66 control subjects and 26 patients with asthma. Smoking histories of control subjects were matched with those of COPD patients. Serum concentrations of TIMP-1 and MMP-9 were determined by ELISA. The circulating TIMP-1 concentration was significantly higher in stable COPD patients than in control and asthmatic subjects, and was significantly negatively correlated with forced expiratory volume in one second/forced vital capacity in COPD patients. The molar ratio between MMP-9 and TIMP-1 was significantly lower in COPD patients than in control subjects. In patients with COPD, the serum TIMP-1 concentration was significantly increased during disease exacerbation. In conclusion, the current findings suggest that serum tissue inhibitors of metalloproteinase-1 concentration can be used as a serum marker of airway obstruction and exacerbation in chronic obstructive pulmonary disease patients.

Adrenal Cortex Hormones↗
PubMed2003

The pilot trial of the prevention of the increase in electrical taste thresholds by zinc containing fluid infusion during chemotherapy to treat primary lung cancer.

It is well known that there are various adverse effects during chemotherapy for cancer treatment. A taste disorder is also seen in 35-70% of patients. It has been reported that a zinc deficiency is associated with the development of these alterations in taste sensation. The purpose of this pilot study was to determine whether the zinc including infusion had the effect on taste disorder in patients with lung cancer. Taste disorder was evaluated as the increase in electrical taste thresholds using an electrogustometer. The plasma zinc concentration was also measured. Although there was no significant correlation, the increase in taste thresholds was detected in many patients who had a low zinc concentration even before receiving chemotherapy. Moreover, after 2 weeks of chemotherapy, almost all patients who did not have a zinc containing infusion showed development of taste disorder (5/5, 100% at chorda tympani area; 4/5, 80% at glossopharyngeal area), whereas no development of taste disorder was observed in those patients receiving a zinc containing infusion. These results suggest the possibility that the administration of zinc during chemotherapy could be a useful supportive therapy for preventing taste disorder and to help maintain a better quality of life.

Aged↗
PubMed2002

Acridine Orange for malaria diagnosis: its diagnostic performance, its promotion and implementation in Tanzania, and the implications for malaria control.

One hundred years ago, Giemsa's stain was employed for the first time for malaria diagnosis. Giemsa staining continues to be the method of choice in most malarious countries, although, in the recent past, several alternatives have been developed that exhibit some advantages. Considerable progress has been made with fluorescent dyes, particularly with Acridine Orange (AO). The literature on the discovery, development and validation of the AO method for malaria diagnosis is reviewed here. Compared with conventional Giemsa staining, AO shows a good diagnostic performance, with sensitivities of 81.3%-100% and specificities of 86.4%-100%. However, sensitivities decrease with lower parasite densities, and species differentiation may occasionally be difficult. The most notable advantage of the AO method over Giemsa staining is its promptness; results are readily available within 3-10 min, whereas Giemsa staining may take 45 min or even longer. This is an important advantage for the organization of health services and the provision of effective treatment of malaria cases. The national malaria control programme of Tanzania, together with the Japan International Co-operation Agency, began to introduce the AO method in Tanzania in 1994. So far, AO staining has been introduced in 70 regional and district hospitals, and 400 laboratory technicians have been trained to use the method. The results of this introduction, which are reviewed here and have several important implications, indicate that AO is a viable alternative technique for the laboratory diagnosis of malaria in highly endemic countries.

Acridine Orange↗
PubMed2001

Role of amino acid residues in left-handed helical conformation for the conformational stability of a protein.

Our previous study of six non-Gly to Gly/Ala mutant human lysozymes in a left-handed helical region showed that only one non-Gly residue at a rigid site had unfavorable strain energy as compared with Gly at the same position (Takano et al., Proteins 2001; 44:233-243). To further examine the role of left-handed residues in the conformational stability of a protein, we constructed ten Gly to Ala mutant human lysozymes. Most Gly residues in human lysozyme are located in the left-handed helix region. The thermodynamic parameters for denaturation and crystal structures were determined by differential scanning calorimetry and X-ray analysis, respectively. The difference in denaturation Gibbs energy (DeltaDeltaG) for the ten Gly to Ala mutants ranged from + 1.9 to -7.5 kJ/mol, indicating that the effect of the mutation depends on the environment of the residue. We confirm that Gly in a left-handed region is more favorable at rigid sites than non-Gly, but there is little difference in energetic cost between Gly and non-Gly at flexible sites. The present results indicate that dihedral angles in the backbone conformation and also the flexibility at the position should be considered for analyses of protein stability, and protein structural determination, prediction, and design.

Amino Acids↗
PubMed2001

Role of non-glycine residues in left-handed helical conformation for the conformational stability of human lysozyme.

To understand the role of non-Gly residues in the left-handed helical conformation for the conformational stability of a protein, the non-Gly to Gly and Ala mutations at six left-handed residues (R21, Y38, R50, Q58, H78, and N118) of the human lysozyme were examined. The thermodynamic parameters for denaturation were determined using a differential scanning calorimeter, and the crystal structures were analyzed by X-ray crystallography. If a left-handed non-Gly had an unfavorable steric interaction between the side-chain Cbeta and backbone, the Gly mutation would be expected to stabilize more than the Ala mutation at the same position. For the mutant human lysozymes, however, there were few differences in the denaturation Gibbs energy (DeltaG) between the Gly and Ala mutants, except for the substitution at position 58. Analysis of the changes in stability (DeltaDeltaG) based on the structures of the wild-type and mutant proteins showed that the experimental DeltaDeltaG value of Q58G was approximately 7 kJ/mol higher than the estimated value without consideration of any local steric interaction. These results indicate that only Q58G increased the stability by elimination of local constraints. The residue 58 is located at the most rigid position in the left-handed non-Gly residues and is involved in its enzymatic function. It can be concluded that the left-handed non-Gly residues do not always have unfavorable strain energies as compared with Gly at the same position.

Amino Acid Substitution↗
PubMed2001

Capping the cost of compliance with the Kyoto Protocol and recycling revenues into land-use projects.

There is the concern among some countries that compliance costs with commitments under the Kyoto Protocol may be unacceptably high. There is also the concern that technical difficulties with the inclusion of land use, land-use change, and forestry activities in non-Annex I countries might lead to an effective exclusion of such activities from consideration under the Protocol. This paper is proposing a mechanism that addresses both these concerns. In essence, it is suggested that parties should be able to purchase fixed-price offset certificates if they feel they cannot achieve compliance through other means alone, such as by improved energy efficiency, increased use of renewable energy, or use of the flexible mechanisms in the Kyoto Protocol. These offset certificates would act as a price cap for the cost of compliance for any party to the Protocol. Revenues from purchase of the offset certificates would be directed to forest-based activities in non-Annex I countries such as forest protection that may carry multiple benefits including enhancing net carbon sequestration.

Energy-Generating Resources↗
PubMed2001

Contribution of polar groups in the interior of a protein to the conformational stability.

It has been generally believed that polar residues are usually located on the surface of protein structures. However, there are many polar groups in the interior of the structures in reality. To evaluate the contribution of such buried polar groups to the conformational stability of a protein, nonpolar to polar mutations (L8T, A9S, A32S, I56T, I59T, I59S, A92S, V93T, A96S, V99T, and V100T) in the interior of a human lysozyme were examined. The thermodynamic parameters for denaturation were determined using a differential scanning calorimeter, and the crystal structures were analyzed by X-ray crystallography. If a polar group had a heavy energy cost to be buried, a mutant protein would be remarkably destabilized. However, the stability (Delta G) of the Ala to Ser and Val to Thr mutant human lysozymes was comparable to that of the wild-type protein, suggesting a low-energy penalty of buried polar groups. The structural analysis showed that all polar side chains introduced in the mutant proteins were able to find their hydrogen bond partners, which are ubiquitous in protein structures. The empirical structure-based calculation of stability change (Delta Delta G) [Takano et al. (1999) Biochemistry 38, 12698--12708] revealed that the mutant proteins decreased the hydrophobic effect contributing to the stability (Delta G(HP)), but this destabilization was recovered by the hydrogen bonds newly introduced. The present study shows the favorable contribution of polar groups with hydrogen bonds in the interior of protein molecules to the conformational stability.

Amino Acids↗
PubMed2001

Changes of serum melatonin level and its relationship to feto-placental unit during pregnancy.

Serum melatonin concentrations were studied in normal pregnant women and in women with several types of pathologic pregnancies, e.g., twins, preeclampsia or intrauterine growth retardation (IUGR). Blood samples were collected from the maternal antecubital vein at 14:00 hr (daytime) and 02:00 hr (nighttime) during pregnancy, and also from the umbilical vein and artery immediately after delivery. Serum melatonin concentrations were measured by radioimmunoassay. Daytime serum melatonin levels in normal (single fetus; singleton) pregnancies were low. While the levels showed an increasing tendency toward the end of pregnancy, no statistically significant changes occurred. On the other hand, the nighttime serum melatonin levels increased after 24 weeks of gestation, with significantly (P < 0.01) high levels after 32 weeks; these values decreased to non-pregnant levels on the 2nd day of puerperium. Nighttime serum melatonin levels were significantly (P < 0.05) higher in twin pregnancies after 28 weeks of gestation than in singleton pregnancies, whereas the patients with severe preeclampsia showed significantly (P < 0.05) lower serum melatonin levels than the mild preeclampsia or the normal pregnant women after 32 weeks of gestation. Melatonin concentrations in umbilical vessels showed a higher tendency in neonates who were born during at night compared with the other neonates; moreover, those in the umbilical artery were generally higher than those in the umbilical vein. The present results indicate that in humans, the maternal serum melatonin levels show a diurnal rhythm, which increases until the end of pregnancy, reflecting some pathologic states of the feto-placental unit. Fetuses may produce melatonin with a circadian rhythm.

Adult↗
PubMed2001

Induction of manganese superoxide dismutase by tumour necrosis factor-alpha in human endometrial stromal cells.

The present study was undertaken to investigate the effect of tumour necrosis factor-alpha (TNFalpha) on superoxide dismutase (SOD) expression in human endometrial stromal cells (ESC) and to determine whether there is a difference in responsiveness to TNFalpha between ESC and decidualized ESC. TNFalpha increased manganese-SOD (Mn-SOD) mRNA level and Mn-SOD activity in a dose-dependent manner in ESC. The concentration of TNFalpha required for an effect was lower for decidualized ESC than for non-decidualized ESC. TNFalpha had no effect on copper-zinc-SOD (Cu,Zn-SOD) expression in either type of cell. Incubation of ESC with actinomycin D, an RNA synthesis inhibitor, blocked TNFalpha-induced Mn-SOD mRNA expression, but cycloheximide, a protein synthesis inhibitor, had no effect. H7, an inhibitor of protein kinase C (PKC), also inhibited TNFalpha-stimulated Mn-SOD mRNA expression in both types of cells. These findings suggest that TNFalpha-induced Mn-SOD expression is regulated at the transcription level and mediated by PKC-dependent phosphorylation and that de-novo protein synthesis is not required for the TNFalpha effect. In summary, TNFalpha induces Mn-SOD expression in human ESC. This phenomenon may be important for protection of ESC from cytokine-mediated oxidative stress.

1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine↗
PubMed2001

Alkaline-resistance model of subtilisin ALP I, a novel alkaline subtilisin.

The alkaline-resistance mechanism of the alkaline-stable enzymes is not yet known. To clarify the mechanism of alkaline-resistance of alkaline subtilisin, structural changes of two typical subtilisins, subtilisin ALP I (ALP I) and subtilisin Sendai (Sendai), were studied by means of physicochemical methods. Subtilisin NAT (NAT), which exhibits no alkaline resistance, was examined as a control. ALP I gradually lost its activity, accompanied by protein degradation, but, on the contrary, Sendai was stable under alkaline conditions. CD spectral measurements at neutral and alkaline pH indicated no apparent differences between ALP I and Sendai. A significant difference was observed on measurement of fluorescence emission spectra of the tryptophan residues of ALP I that were exposed on the enzyme surface. The fluorescence intensity of ALP I was greatly reduced under alkaline conditions; moreover, the reduction was reversed when alkaline-treated ALP I was neutralized. The fluorescence spectrum of Sendai remained unchanged. The enzymatic and optical activities of NAT were lost at high pH, indicating a lack of functional and structural stability in an alkaline environment. Judging from these results, the alkaline resistance is closely related to the surface structure of the enzyme molecule.

Autolysis↗
PubMed2001

Regulation and role of vascular endothelial growth factor in the corpus luteum during mid-pregnancy in rats.

The present study was undertaken to investigate the role of vascular endothelial growth factor (VEGF) in luteal angiogenesis and the regulation of VEGF in the corpus luteum (CL) during mid-pregnancy in rats. Protein concentrations and mRNA levels of VEGF in the CL significantly increased from Day 9 to Day 12 and remained at the same level as Day 12 until Day 15. To study whether estradiol is involved in VEGF expression between Day 12 and Day 15, rats undergoing hypophysectomy-hysterectomy on Day 12 were treated with estradiol until Day 15. Protein concentrations and mRNA levels of VEGF in the CL were significantly decreased by hypophysectomy-hysterectomy, and this inhibitory effect was completely reversed by estradiol treatment. Changes in vascular density in the CL were parallel to those in VEGF expression. To examine whether the effect of estradiol is mediated by VEGF, anti-VEGF antibody was administered to hypophysectomized-hysterectomized rats simultaneously with estradiol. The recovery in the vascular density, CL weight, and serum progesterone concentration caused by estradiol was significantly inhibited by the anti-VEGF antibody treatment. In conclusion, the present study has demonstrated that VEGF contributes to luteal angiogenesis, CL development, and progesterone production during mid-pregnancy in rats and that luteal VEGF expression is increased by estradiol.

Animals↗
PubMed2001

Identification of N-terminal autodigestion target site in subtilisin ALP I.

Autodigestion of subtilisin ALP I (ALP I), secreted from the alkalophilic Bacillus sp. NKS-21 and its predicted amino acid sequence having about 60% identity with other alkaline subtilisins, was examined under alkaline conditions. At the alkaline pH of 12, ALP I was rapidly degraded, and almost no breakdown products were detectable. However, by incubating ALP I at 5 degrees C for an extended time, a couple of specific peptides (26.7 kDa and 25.6 kDa) were accumulated. Each of them was purified and amino acid sequences of these fragments were found. Both peptides appeared to start at Gly-19 of the mature sequence of ALP I.

Amino Acid Sequence↗