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Masaaki Ito

Publications and source records attributed to Masaaki Ito.

At least 19 recordsLinked to original sources
PubMed2007

Preparation of N-acylated proteins modified with fatty acids having a specific chain length using an insect cell-free protein synthesis system.

To establish a strategy to generate N-acylated proteins modified with fatty acids having a specific chain length, tGelsolin-streptag, an epitope-tagged model protein having an N-myristoylation motif, was synthesized using an insect cell-free protein synthesis system in the presence of acyl-CoA with various fatty acid chain lengths. It was found that the fatty acid species attached to the N-termini fully depended on the acyl-CoA species added to the reaction mixture. N-Acylated proteins with fatty acid chain lengths of 8, 10, 12, and 14 were generated successfully.

Acetylation↗
PubMed2007

The relationship between aortic augmentation index and pulse wave velocity: an invasive study.

OBJECTIVES: The aortic augmentation index (AI) and aortic pulse wave velocity (PWV) are known to be indicators of arterial stiffness. However, it is not clear whether aortic AI and PWV reflect aortic stiffness in similar ways. We investigated the relationship between aortic AI and PWV by measuring them directly using a catheter technique. DESIGN AND METHODS: Forty-one patients, aged 34-79 years, were studied during diagnostic cardiac catheterization. Aortic pressures were measured using a catheter-tip manometer at two points, one in the ascending aorta and one 40 cm distally in the descending aorta. Aortic AI was defined as the difference between early and late pressure peaks divided by the pulse pressure of the ascending aorta. Aortic PWV was calculated as the distance between the two measuring sites divided by the transit time. We also examined the effects of vasodilatation on AI and PWV by the intra-aortic administration of nitroglycerin in 15 patients. RESULTS: AI was significantly related to age, systolic aortic pressure, heart rate, left ventricular ejection time, and height. Aortic PWV showed an association only with age and systolic aortic pressure. There was no significant relationship between aortic AI and PWV (r = 0.28, NS). Nitroglycerin also produced different effects on aortic AI and PWV: aortic AI was significantly decreased (-0.17, P < 0.01) after nitroglycerin, but PWV remained unchanged (+0.4 m/s, NS). CONCLUSIONS: Aortic AI and PWV cannot be used interchangeably as an index of arterial stiffness. AI may not be a true indicator of arterial stiffness, but an index of wave reflection including PWV.

Adult↗
PubMed2006

Changes in vertebral wedging rate between supine and standing position and its association with back pain: a prospective study in patients with osteoporotic vertebral compression fractures.

STUDY DESIGN: Prospective consecutive series. OBJECTIVE: To analyze supine and standing radiographs and the association of back pain using subjective pain criteria. SUMMARY OF BACKGROUND DATA: It has been considered that there is little correlation between the degree of collapse of the vertebral body and the level of pain. In previous studies, however, measurements have only been based on supine radiographs. Although there were 2 authors who reported the results of supine lateral and standing lateral radiographs in patients with thoracolumbar vertebral fractures, as far as we know, there has not been any detailed report concerning the correlation between radiologic findings using supine and standing lateral radiographs and back pain. METHODS: We examined 100 consecutively treated patients, prospectively. Back pain and the supine and standing radiographs were assessed 1 month after injury. Changes in vertebral wedging rate (WR) from supine to standing position (Delta WR) was reported by the following equation: Delta WR = WR(standing)-WR(supine). RESULTS: The median age of the cohort was 75 years (range, 60-89 years). The median VAS of back pain at supine position, at standing position, and when standing erect was 13, 33, and 41, respectively. The median wedging rate on the supine and standing radiographs were 28% and 37%, respectively (P < 0.001). There was a significant correlation between Delta WR and back pain when standing erect (r = 0.79, P < 0.001). CONCLUSION: Changes in vertebral wedging rate between supine and standing position and its association with back pain may give a clue to the pathogenesis of pain from osteoporotic thoracolumbar vertebral compression fractures.

Aged↗
PubMed2006

Urocortin-induced decrease in Ca2+ sensitivity of contraction in mouse tail arteries is attributable to cAMP-dependent dephosphorylation of MYPT1 and activation of myosin light chain phosphatase.

Urocortin, a vasodilatory peptide related to corticotropin-releasing factor, may be an endogenous regulator of blood pressure. In vitro, rat tail arteries are relaxed by urocortin by a cAMP-mediated decrease in myofilament Ca2+ sensitivity through a still unclear mechanism. Here we show that contraction of intact mouse tail arteries induced with 42 mmol/L KCl or 0.5 micromol/L noradrenaline was associated with a approximately 2-fold increase in the phosphorylation of the regulatory subunit of myosin phosphatase (SMPP-1M), MYPT1, at Thr696, which was reversed in arteries relaxed with urocortin. Submaximally (pCa 6.1) contracted mouse tail arteries permeabilized with alpha-toxin were relaxed with urocortin by 39+/-3% at constant [Ca2+], which was associated with a decrease in myosin light chain (MLC20Ser19), MYPT1Thr696, and MYPT1Thr850 phosphorylation by 60%, 28%, and 52%, respectively. The Rho-associated kinase (ROK) inhibitor Y-27632 decreased MYPT1 phosphorylation by a similar extent. Inhibition of PP-2A with 3 nmol/L okadaic acid had no effect on MYPT1 phosphorylation, whereas inhibition of PP-1 with 3 micromol/L okadaic acid prevented dephosphorylation. Urocortin increased the rate of dephosphorylation of MLC20Ser19 approximately 2.2-fold but had no effect on the rate of contraction under conditions of, respectively, inhibited kinase and phosphatase activities. The effect of urocortin on MLC20Ser19 and MYPT1 phosphorylation was blocked by Rp-8-CPT-cAMPS and mimicked by Sp-5,6-DCl-cBIMPS. In summary, these results provide evidence that Ca(2+)-independent relaxation by urocortin can be attributed to a cAMP-mediated increased activity of SMPP-1M which at least in part is attributable to a decrease in the inhibitory phosphorylation of MYPT1.

Animals↗
PubMed2006

Characterization and function of MYPT2, a target subunit of myosin phosphatase in heart.

Characterization of cardiac MYPT2 (an isoform of the smooth muscle phosphatase [MP] target subunit, MYPT1) is described. Several features of MYPT2 and MYPT1 were similar, including: a specific interaction with the catalytic subunit of type 1 phosphatase, delta isoform (PP1cdelta); interaction of MYPT2 with the small heart-specific MP subunit; interaction of the C-terminal region of MYPT2 with the active form of RhoA; phosphorylation by Rho-kinase at an inhibitory site, Thr646 and thiophosphorylation at Thr646 inhibited activity of the MYPT2-PP1cdelta complex. MYPT2 activated PP1cdelta activity, using light chains from smooth and cardiac muscle, by reducing K(m) and increasing k(cat). The extent of activation (k(cat)) was greater than for MYPT1 and could reflect distinct N-terminal sequences in the two MYPT isoforms. Adenovirus-mediated gene transfer of MYPT2 and PP1cdelta reduced the phosphorylation level of cardiac light chains following stimulation with A23187. Overexpression of MYPT2 and PP1cdelta blocked the angiotensin II-induced sarcomere organization in cultured cardiomyocytes. Electron microscopy indicated locations of MYPTs, at, or close to, the Z-line, the A band and mitochondria. Similarity of the two MYPT isoforms suggests common enzymatic mechanisms and regulation. Cardiac myosin is a substrate for the MYPT2 holoenzyme, but the Z-line location raises the possibility of other substrates.

Angiotensin II↗
PubMed2006

Association of the PIG3 promoter polymorphism with invasive bladder cancer in a Japanese population.

PIG3 (p53-induced gene 3) is one of the targets of TP53 and is involved in apoptosis. The promoter of PIG3 contains a variable number of tandem repeats (VNTRs) of pentanucleotides (TGYCC)n (Y = C or T) and the number of VNTRs was reported to be correlated with the activation by TP53. In this study, the clinical significance of the PIG3 promoter VNTRs was analyzed in the bladder cancer patients using the genome DNAs from 338 controls and 273 bladder cancer patients. There was no significant difference in the allele frequency of the PIG3 promoter VNTRs between them. However, the presence of 14 or less repeats allele was associated with higher cancer grade (P = 0.038) and higher stage in relative risk (adjusted odds ratio = 2.31, 95% confidence interval = 1.05-5.90). These data suggested that the PIG3 promoter VNTRs was associated with generation of invasive bladder cancer.

Aged↗
PubMed2006

N-Terminal protein modifications in an insect cell-free protein synthesis system and their identification by mass spectrometry.

To evaluate the ability of an insect cell-free protein synthesis system to generate proper N-terminal cotranslational protein modifications such as removal of the initiating Met, N-acetylation, and N-myristoylation, several mutants were constructed using truncated human gelsolin (tGelsolin) as a model protein. Tryptic digests of these mutants were analyzed by MALDI-TOF MS and MALDI-quadrupole-IT-TOF MS. The wild-type tGelsolin, which is an N-myristoylated protein, was found to be N-myristoylated when myristoyl-CoA was added to the in vitro translation reaction mixture. N-myristoylation did not occur on the Gly-2 to Ala mutant, in which the N-myristoylation motif was disrupted, whereas this mutant was found to be N-acetylated after removal of the initiating Met. Analyses of Gly-2 to His and Leu-3 to Asp mutants revealed that the amino acids at positions 2 and 3 strongly affect the susceptibility of the nascent peptide chain to removal of the initiating Met and to N-acetylation, respectively. These results suggest that N-terminal modifications occurring in the insect cell-free protein synthesis system are quite similar to those observed in the mammalian protein synthesis system. Thus, a combination of the cell-free protein synthesis system with MS is an effective strategy to analyze protein modifications.

Acetylation↗
PubMed2006

Intersphincteric resection in patients with very low rectal cancer: a review of the Japanese experience.

PURPOSE: This study was designed to evaluate the feasibility and oncologic and functional outcomes of intersphincteric resection for very low rectal cancer. METHODS: A feasibility study was performed using 213 specimens from abdominoperineal resections of rectal cancer. Oncologic and functional outcomes were investigated in 228 patients with rectal cancer located <5 cm from the anal verge who underwent intersphincteric resection at seven institutions in Japan between 1995 and 2004. RESULTS: Curative operations were accomplished by intersphincteric resection in 86 percent of patients who underwent abdominoperineal resection. Complete microscopic curative surgery was achieved by intersphincteric resection in 225 of 228 patients. Morbidity was 24 percent, and mortality was 0.4 percent. During the median observation time of 41 months, rate of local recurrence was 5.8 percent at three years, and five-year overall and disease-free survival rates were 91.9 percent and 83.2 percent, respectively. In 181 patients who received stoma closure, 68 percent displayed good continence, and only 7 percent showed worsened continence at 24 months after stoma closure. Patients with total intersphincteric resection displayed significantly worse continence than patients with partial or subtotal resection. CONCLUSIONS: Curability with intersphincteric resection was verified histologically, and acceptable oncologic and functional outcomes were obtained by using these procedures in patients with very low rectal cancer. However, information on potential functional adverse effects after intersphincteric resection should be provided to patients preoperatively.

Adult↗
PubMed2006

Force- and relaxation-frequency relations in patients with diastolic heart failure.

BACKGROUND: Chronotropic effects on myocardial contractility (the positive force-frequency relation) and relaxation (the positive relaxation-frequency relation) are impaired in patients with congestive heart failure and depressed left ventricular (LV) ejection fraction (systolic heart failure [SHF]). However, the force- and relaxation-frequency relation and LV-arterial coupling in patients with diastolic heart failure (DHF) has not been fully investigated. METHODS AND RESULTS: To examine inotropic and lusitropic responsiveness to atrial pacing, LV pressure-volume relations were measured using a conductance catheter and microtip manometer in patients with DHF (n = 18) and SHF (n = 11). In patients with SHF, an increase in heart rate by 40 beat/min did not affect LV end-systolic elastance (Ees), which reflects LV contractility, or the time constant of LV relaxation. By contrast, in patients with DHF, an increase in heart rate by 40 beat/min significantly enhanced Ees (2.1 vs 2.9 mm Hg/mL, P < .05) but not the time constant. Furthermore, LV-arterial coupling, quantified as Ees/arterial elastance, was impaired during pacing in patients with DHF (1.1 vs 0.8, P < .05) as well as SHF. CONCLUSIONS: In patients with DHF, the force-frequency relation was preserved, but the relaxation-frequency relation was impaired. Furthermore, LV-arterial coupling was impaired as heart rate increased, which may be related to the impaired LV function. These results suggest that the impaired relaxation-frequency relation and exacerbated LV-arterial coupling during tachycardia may be an important therapeutic target in patients with DHF.

Adult↗
PubMed2006

Single beat determination of regional myocardial strain measurements in patients with atrial fibrillation.

Atrial fibrillation (AF) and congestive heart failure share several features and often coexist in the same patients; therefore, serial assessment of regional myocardial function is important for patients with AF. However, the clinical assessment of regional myocardial function in AF is unreliable and difficult because of beat-to-beat variation. Recent reports have shown that the ratio of the preceding to the prepreceding R-R interval (RR1/RR2) can be used to assess global left ventricular systolic function. Accordingly, we tested the hypothesis that regional wall motion can be estimated from a single beat based on RR1/RR2 in patients with AF. Peak systolic strain at basal, mid, and apical segments of the septal wall was measured by Doppler tissue imaging from an apical 4-chamber view for 30 seconds in 50 patients with AF (mean ejection fraction 52.1 +/- 15.3%; mean heart rate 76.4 +/- 16.0/min). There was a positive linear relationship between peak strain and RR1/RR2 and RR1, and a negative relationship with RR2, with the correlation of peak strain to RR1/RR2 was better than that in RR1 or RR2. Furthermore, peak strain at RR1/RR2 = 1 was calculated from the linear regression and compared with the average measured value of all recorded cardiac cycles in each patient. In all cases, average peak strain showed a significant positive correlation with RR1/RR2 at each segment (r = 0.99). In conclusion, regional myocardial strain at RR1/RR2 = 1 on the linear regression represents the average value of all recorded cardiac cycles in patients with AF.

Aged↗
PubMed2006

NKG2D ligation without T cell receptor engagement triggers both cytotoxicity and cytokine production in dendritic epidermal T cells.

NKG2D is an activating receptor that recognizes self-ligands induced on stressed, infected, or transformed cells. In mice, two NKG2D isoforms (NKG2D-S (short) and NKG2D-L (long)) that associate differentially with DAP10 and DAP12 adaptor proteins exist. Differential expression of these isoforms and adaptor proteins depending on the activating state and cell types determines distinct functional outcomes of NKG2D ligation: direct activation of cytotoxicity in natural killer (NK) cells and cytokine production in activated NK cells, but only costimulation in activated CD8+ T cells. Intraepithelial gammadelta T cells of the mouse skin, termed dendritic epidermal T cells (DETCs), were also shown to express NKG2D, but the NKG2D isoform(s) expressed in DETCs have not been determined. Furthermore, functional outcomes of NKG2D ligation in DETCs are largely unknown, although costimulation of DETC-mediated cytotoxicity by NKG2D was demonstrated. Here, we show that DETCs constitutively express NKG2D-S, NKG2D-L, DAP10, and DAP12 transcripts as well as cell surface NKG2D protein. Blocking of NKG2D inhibited DETC-mediated cytotoxicity against target cells that do not express T cell receptor ligands. Cross-linking of NKG2D on DETCs induced IFN-gamma production. These findings demonstrate that DETCs constitutively express NKG2D that acts as a primary activating receptor, and indicate its important role in cutaneous immune surveillance.

Adaptor Proteins, Signal Transducing↗
PubMed2006

Mutations in the desmoglein 4 gene are associated with monilethrix-like congenital hypotrichosis.

The gene encoding human desmoglein 4 (DSG4) was recently cloned, and a mutation in this gene has been reported in several consanguineous Pakistani families affected with localized autosomal recessive hypotrichosis (LAH). In addition, various mutations in the Dsg4 gene have been identified in animal models of hypotrichosis that share a characteristic phenotype called "lanceolate hair". To date, the features of the hair-shaft anomaly in patients with LAH have not been well described. We report a Japanese patient affected with congenital hypotrichosis that was originally diagnosed as monilethrix because she had a hair-shaft abnormality that resembled moniliform hair. However, no mutations were found in the type II hair keratin genes, hHb1, hHb3, and hHb6, whose mutations cause monilethrix. Instead, we identified novel compound heterozygous mutations in the DSG4 gene of our patient. On the maternal allele is a novel S192P transition within the extracellular cadherin II domain of DSG4; on the paternal allele is a novel 2039insT mutation leading to the generation of unstable transcripts. Here we present the observation that mutations in the DSG4 gene can cause monilethrix-like congenital hypotrichosis. Based on our findings, we propose that LAH and monilethrix could overlap.

Alleles↗
PubMed2006

High throughput comparative genomic hybridization array analysis of multifocal urothelial cancers.

The purpose of this study was to examine genetic alterations occur during synchronous or metachronous multifocal development of urothelial cancers on the whole genome using a comparative genomic hybridization (CGH) array. We used 10 tumor pairs (2 tumors for each patient), in which we had previously defined a clonal relationship by microsatellite analysis. For CGH array analysis, Vysis GenoSensor Array 300 kit was used. An unsupervised hierarchical cluster analysis revealed that the tumors from one patient were clustered together independent of the tumors of all other patients. On the other hand, many genetic divergences among multifocal urothelial cancers were newly found by a CGH array analysis. The concordant genetic alteration patterns of the chromosomal arm in tumor pairs were most frequently observed in 9p, 9q, 8p, 7p, 7q and 11q, while discordant patterns were most frequently found in 15q, 20q, 2q, 10p and 11q. Investigation using a CGH array showed that genetically stable multifocal tumors were less frequent, and that a large percentage of urothelial cancers accumulate genetic alterations during multifocal development by clonal evolution. We might have to consider these genetic accumulations during multifocal development when designing strategies for prevention and detection of recurrent multifocal urothelial cancers. CGH array can be a powerful tool for genetic analysis of multifocal urothelial cancer.

Chromosome Aberrations↗
PubMed2006

Heat shock-induced augmentation of vascular contractility is independent of rho-kinase.

In a previous study, we demonstrated that heat shock augments the contractility of vascular smooth muscle through the stress response. 2. In the present study, we investigated whether Rho-kinases play a role in heat shock-induced augmentation of vascular contractility in rat isolated aorta. 3. Rat aortic strips were mounted in organ baths, exposed to 42 C for 45 min and subjected to contractile or relaxant agents 5 h later. 4. The level of expression of Rho-kinases in heat shock-exposed tissues was no different to that of control tissues, whereas heat shock induced heat shock protein (Hsp) 72 at 3 and 5 h. Heat shock resulted in an increase in vascular contractility in response to phenylephrine 5 h later. 5. The Rho-kinase inhibitors Y27632 (30 nmol/L-10 mmol/L) or HA 1077 (10 nmol/L-10 mmol/L) relaxed 1.0 mmol/L phenylephrine-precontracted vascular strips in a concentration-dependent manner; these effects were attenuated in heat shock-exposed strips. Pretreatment with Y27632 resulted in greater inhibition of the maximum contraction in control strips compared with those in heat shock-exposed strips. 6. The results of the present study suggest that Rho-kinases are unlikely to be involved in heat shock-induced augmentation of vascular contractility.

Actins↗
PubMed2006

Management of concomitant ureteral carcinoma in situ at radical cystectomy.

OBJECTIVE: We conducted a retrospective study to evaluate and define the management of concomitant ureteral carcinoma in situ (CIS) at radical cystectomy. METHODS: For 158 consecutive patients, who underwent radical cystectomy for invasive bladder cancer, ureteral CIS missed by preoperative examinations were evaluated by intraoperative analysis of frozen sections or postoperative histological analysis. The median follow-up period was 3.4 years. RESULTS: In total, 15 concomitant ureteral CIS were diagnosed by intraoperative (n=9) or postoperative analysis (n=6). Additional ureteral resection achieved no malignancies in the final ureteral margins of eight patients. During the follow-up period, five patients (3.6%) suffered from tumor recurrence in the upper urinary tract in total, as did three (20%) among the 15 patients with ureteral CIS missed by preoperative examinations. No recurrence was identified in the eight patients with no malignancy in the final ureteral margins after additional resection. Furthermore, multivariate analysis indicated that the presence of bladder CIS was a risk factor for the presence of concomitant ureteral CIS. CONCLUSIONS: Detection of concomitant ureteral CIS by intraoperative studies, in combination with complete resection of ureteral CIS, might be beneficial for patients with risk factors such as bladder CIS.

Adult↗
PubMed2006

Beneficial acute effects of rho-kinase inhibitor in patients with pulmonary arterial hypertension.

BACKGROUND: Pulmonary arterial hypertension (PAH) is a poor prognostic disease with limited treatment options. Rho-kinase is involved in the pathophysiology of several diseases underlying smooth muscle hypercontraction, so the purpose of this study was to investigate the efficacy of fasudil, a Rho-kinase inhibitor, in patients with PAH. METHODS AND RESULTS: Fasudil 30 mg was intravenously injected over 30 min in 8 patients (all female, mean +/- SD, 41+/-11 years) with PAH. The lowest total pulmonary resistance (TPR) time was within 30-60 min after administration. Administration of fasudil decreased TPR from 1,069+/-573 dyne . s . cm (-5) to 809+/-416 dyne . s . cm(-5) (p<0.005) and mean pulmonary arterial pressure from 41.3+/-12.8 mmHg to 37.9+/-14.6 mmHg (p<0.05). The cardiac index was increased from 2.42+/-0.73 L . min(-1) . m(-2) to 2.84+/-0.79 L . min(-1) . m(-2) (p<0.02). Systemic vascular resistance and systolic systemic arterial pressure (SAP) were decreased (p<0.005, p=0.09, respectively), but the decrease in SAP was small (-6.4+/-9.1 mmHg). CONCLUSION: These results suggest that Rho-kinase is involved in the pathogenesis of human PAH and that fasudil is a novel therapeutic agent.

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