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Masayuki Takeda

Publications and source records attributed to Masayuki Takeda.

At least 37 records · Page 2Linked to original sources
PubMed2004

DRESSA: biosensing of dioxin and dioxin-like chemicals using secreted alkaline phosphatase.

In this article, we describe a highly sensitive biosensing system, DRESSA, for detection of dioxin and dioxin-like chemicals. Tandem copies of the dioxin-responsive element (DRE) fused to a minimal viral promoter were subcloned into an expression plasmid upstream of a secreted alkaline phosphatase (SEAP) gene. When murine hepatoma cell line Hepa-1c1c7 was stably transfected with this construct, established sensor clones secreted SEAP following stimulation with 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). A clone HeDS49 was found to be extremely sensitive; it secreted SEAP in response to TCDD in dose- and time-dependent manners, and the minimal detection limit was 100 fM. To detect more than 6 pM of TCDD, the whole assay time (from cell seeding to measurement of SEAP activity) could be reduced to 4h. Secretion of SEAP was induced selectively by other activators of DRE (3-methylcholanthrene, benzo[a]pyrene, and beta-naphthoflavone) but not by activators of unrelated responsive elements. These data suggested that because of the rapidity, easiness, specificity, and high sensitivity of DRESSA, it is more suitable than currently available detection systems for dioxin and dioxin-like chemicals and would be of great advantage to high-throughput screening of these pollutants in environmental samples.

Alkaline Phosphatase↗
PubMed2004

Nitric oxide-mediated regulation of connexin43 expression and gap junctional intercellular communication in mesangial cells.

This study investigated a potential role of nitric oxide (NO) in the regulation of gap junctional intercellular communication (GJIC). Incubation of mesangial cells (MC) with NO donor S-nitroso-N-acetylpenicillamine (SNAP) enhanced both basal and 8-bromo-cAMP-stimulated GJIC as well as expression of gap junction protein connexin43 (Cx43). This potentiating action of SNAP on Cx43 expression was mimicked by two other NO donors and significantly blocked by soluble guanylate cyclase inhibitor 1H-[1,2,4]oxadiazolo[4,3,-alpha]quinoxalin-1-1. Guanosine 3',5'-cyclic monophosphate (cGMP) analogue 8-bromo-cGMP exerted an effect similar to NO, whereas another cGMP analogue, 8-pCPT-cGMP, which selectively activates cGMP-dependent kinase without affecting cGMP-inhibited phosphodiesterase (PDE3), had no effect. Moreover, the synergistic action of NO on Cx43 expression was completely prevented by protein kinase A inhibitor H89 but not by cGMP-dependent kinase inhibitor Rp-8-Br-PET-cGMP. These results suggested a possible involvement of NO-cAMP interaction via cGMP-mediated inhibition of PDE3. Indeed, PDE3 inhibitor cilostamide caused potentiation of 8-bromo-cAMP-elicited elevations of Cx43 expression that is similar to the effect of SNAP, and an elevation of intracellular cAMP was detected in SNAP-treated cells. With the use of genetically engineered reporter MC that express secreted alkaline phosphatase under the control of the cAMP response element, significant potentiation of cAMP-elicited activation of cAMP response element by SNAP was found. This effect was abrogated in the presence of PDE3 inhibitor cilostamide. Taken together, the results suggest that NO is involved in the control of GJIC and Cx43 expression. This effect of NO is due to activation of protein kinase A via cGMP-dependent inhibition of PDE3 activity.

3',5'-Cyclic-AMP Phosphodiesterases↗
PubMed2004

AP-1-independent sensitization to oxidative stress-induced apoptosis by proteasome inhibitors.

Hydrogen peroxide (H(2)O(2)) induces apoptosis of mesangial cells via c-Jun N-terminal kinase (JNK)-activator protein-1 (AP-1) and extracellular signal-regulated kinase (ERK)-AP-1 pathways. We recently found that subtoxic doses of proteasome inhibitors, MG132 and lactacystin, dramatically enhanced H(2)O(2)-induced apoptosis in mesangial cells. In this report, we examined molecular mechanisms involved in this phenomenon, especially focusing on AP-1 pathways. Reporter assays showed that MG132 induced activation of AP-1. However, pharmacological inhibitors of AP-1, retinoic acid, and curcumin, did not suppress the proapoptotic effect of MG132. Suppression of JNK-AP-1 by transfection with either a dominant-negative mutant of JNK or a dominant-negative mutant of c-Jun did not attenuate the apoptosis enhancement by MG132. Similarly, suppression of ERK-AP-1 by PD98059 or dominant-negative mutants of ERK did not affect the apoptosis-promoting effect of MG132. Interestingly, pretreatment with MG132 did not enhance activation of AP-1 by H(2)O(2). These data suggested a novel, AP-1-independent promotion of apoptosis by proteasome inhibitors.

Animals↗
PubMed2004

Overexpression of epithelial sodium channels in epithelium of human urinary bladder with outlet obstruction.

OBJECTIVES: To examine whether the epithelial sodium channel (ENaC) is expressed in the human urinary bladder and how its expression changes in association with outlet obstruction. Detrusor instability occurs in association with bladder outlet obstruction. The increase of afferent activity is one of the possible mechanisms for this detrusor instability. The ENaC expressed in mammals has been implicated in various mechanosensory functions. METHODS: Specimens of urinary bladder mucosa were obtained from 9 controls and 9 patients with bladder outlet obstruction verified by the International Prostate Symptom Score, prostate volume, and urodynamic tests. In 7 patients with outlet obstruction, involuntary detrusor contraction was demonstrated. The expression and localization of ENaC proteins was examined using immunofluorescent staining. The quantification of ENaC gene expression was assessed by real-time reverse transcriptase-polymerase chain reaction. RESULTS: The alpha-ENaC, beta-ENaC, and gamma-ENaC proteins were expressed in human urinary bladder epithelium with outlet obstruction, and the alpha-ENaC and gamma-ENaC proteins were virtually unstained in the control bladders. Alpha-ENaC, beta-ENaC, and gamma-ENaC mRNA were detected in 1, 6, and 4 of 9 control bladders, respectively. Each ENaC mRNA was clearly present in all obstructed bladders. The expression levels of each subunit in the obstructed bladders were significantly greater than those in controls. The quantified ENaC expression correlated significantly with the storage symptom score. CONCLUSIONS: The ENaC expressed in the bladder epithelium might be implicated in the mechanosensory transduction in the bladder afferent pathways, thereby inducing detrusor instability by outlet obstruction.

Aged↗
PubMed2004

Efficiently finding regulatory elements using correlation with gene expression.

We present an efficient algorithm for detecting putative regulatory elements in the upstream DNA sequences of genes, using gene expression information obtained from microarray experiments. Based on a generalized suffix tree, our algorithm looks for motif patterns whose appearance in the upstream region is most correlated with the expression levels of the genes. We are able to find the optimal pattern, in time linear in the total length of the upstream sequences. We implement and apply our algorithm to publicly available microarray gene expression data, and show that our method is able to discover biologically significant motifs, including various motifs which have been reported previously using the same data set. We further discuss applications for which the efficiency of the method is essential, as well as possible extensions to our algorithm.

Algorithms↗
PubMed2003

Diagnosis and treatment of voiding symptoms.

Lower urinary tract symptoms (LUTS) are associated with lower urinary tract dysfunction. Symptoms are the subjective indicator of a disease or change in condition as perceived by the patient, caregiver, or partner and may lead the individual to seek help from health care professionals. LUTS are usually qualitative and, therefore, cannot usually be used to make a definitive diagnosis. LUTS also can indicate pathologies other than lower urinary tract dysfunction, such as urinary infection. LUTS are divided into 7 groups: storage, voiding (obstructive), postmicturition symptoms and 4 others. Voiding symptoms, which are caused by lower urinary tract obstruction, include slow stream, splitting or spraying, intermittency, hesitancy, straining, and terminal dribble. Postmicturition symptoms, which are experienced immediately after micturition, consist of the feeling of incomplete emptying and postmicturition dribble. Postmicturition dribble describes the involuntary loss of urine immediately after the individual has finished passing urine; in men, usually after leaving the toilet and in women, after rising from the toilet. Hence, postmicturition dribble is elicited by different situations or is considered as having different implications. For example, although postmicturition dribble usually implies incomplete emptying (voiding symptoms) in elderly men with benign prostatic hyperplasia, postmicturition dribble is often considered as urinary incontinence (a storage symptom) in many patients, even with bladder outlet obstruction. In such cases, detailed history taking and further evaluation, such as urinary flowmetry, postvoid residual volume, and comprehensive urodynamic evaluation, should be performed as appropriate. If no urodynamic abnormalities of either the detrusor or the outlet can be detected despite significant LUTS, factors unrelated to the lower urinary tract may be responsible for the voiding symptoms.

Female↗
PubMed2003

Current and future directions in diagnostic markers in interstitial cystitis.

Interstitial cystitis (IC) is a chronic bladder disorder of unknown etiology that is often diagnosed by symptom criteria with or without cystoscopic findings. Several potential diagnostic markers have recently been described that may facilitate diagnosis of this disorder. A summary of the literature and a discussion regarding these biomarkers is provided, along with a brief discussion of new biomarkers presented at the meeting.

Biomarkers↗
PubMed2003

The methylentetrahydrofolate reductase C677T point mutation is a risk factor for vascular access thrombosis in hemodialysis patients.

BACKGROUND: Many reports indicate that a high homocysteine (Hcy) level is a potential risk factor for such thrombotic diseases as arteriosclerosis, myocardial infarction, and cerebral infarction in healthy individuals or hemodialysis (HD) patients. The methylentetrahydrofolate reductase (MTHFR) C677T polymorphism has been reported to be closely related to plasma Hcy level. METHODS: Using a cross-sectional design in this study, the relationship between arteriovenous fistula (AVF) obstruction and the MTHFR C677T point mutation was examined in 337 HD patients. RESULTS: Results of multivariate analysis showed no significant influence of age, HD therapy duration, sex, or the presence of diabetes mellitus, cerebral infarction, or myocardial infarction. Only the presence of the MTHFR C677T polymorphism yielded a significant difference. Percentages of patients who experienced AVF obstruction were as follows: CC (12.6%), CT (20.3%), and TT (31.8%). The number of those who experienced obstruction was significantly larger with the TT than CC (P < 0.01). Moreover, total obstruction episode ratios were as follows: CC, 1 in 107.21 episodes/patient-month; CT, 1 in 74.08 episodes/patient-month; and TT, 1 in 50.33 episodes/patient-month. Episode percentages tended to be greater when the degree of mutation was greater, and a significant difference was observed between the CC and TT alleles (P < 0.01). CONCLUSION: Although AVF obstruction is affected by numerous factors, there was a strong relationship between MTHFR C677T mutation and AVF obstruction. These findings suggest that the MTHFR C677T point mutation could serve as an important indicator in identifying susceptibility to AVF obstruction.

Arteriovenous Shunt, Surgical↗
PubMed2003

Retroperitoneoscopic nephron-sparing surgery of renal tumor using a microwave tissue coagulator without renal ischemia: comparison with open procedure.

PURPOSE: It is ideal to use not a transperitoneal but a retroperitoneal approach for both open and endoscopic partial nephrectomy. We compared the results of retroperitoneoscopic nephron-sparing surgery for small renal tumors using a microwave tissue coagulator without renal pedicle clamping with those of a retroperitoneal open procedure. PATIENTS AND METHODS: Between 1996 and 2002, eight patients with small renal tumors underwent retroperitoneoscopic partial nephrectomy without renal ischemia, and nine patients with small renal tumors underwent open partial nephrectomy via a retroperitoneal approach. Both groups were operated on using a microwave tissue coagulator. RESULTS: Retroperitoneoscopic partial nephrectomy without renal ischemia was performed without any major or minor complications in any patient. The mean operation time for retroperitoneoscopic surgery was significantly longer than that for open partial nephrectomy (221.9 minutes v 145.9 minutes; P = 0.0004). However, the mean estimated blood loss for retroperitoneoscopic surgery was less than that for open partial nephrectomy (137.5 mL v 334.8 mL; P = 0.012). In addition, the retroperitoneoscopic group seemed to recover more rapidly than the open surgery group. CONCLUSIONS: Retroperitoneoscopic nephron-sparing surgery of small renal tumors using a microwave tissue coagulator without renal ischemia is feasible as minimally invasive procedure. It results in saving renal function, minimal blood loss, and rapid recovery.

Aged↗
PubMed2003

Relationship of bladder dysfunction to lesion site in multiple sclerosis.

PURPOSE: We investigated the relationship of voiding dysfunction type and the lesion site in patients with multiple sclerosis. MATERIALS AND METHODS: Voiding dysfunction was evaluated in 32 patients with multiple sclerosis using the International Prostate Symptom Score and urodynamic tests. Lesion sites were determined by combined neurological examination and magnetic resonance imaging findings. RESULTS: Compared with reports from Western countries the ratio of emptying-to-filling symptoms was high in Japan. Of urinary symptoms only filling correlated with disability status and disease duration. Urinary symptoms were not related to lesion sites. Urodynamic evaluation revealed detrusor hyperreflexia in 14 of 32 patients, hyporeflexia or areflexia in 12, detrusor hyperreflexia with impaired contractile function in 4, a low compliance bladder in 1 and normal function in 1. Of 14 patients with hyperreflexia 13 had overactive sphincter concurrently. Incompetent sphincter was identified in 2 patients who had detrusor hyperreflexia with impaired contractility and in 1 with a low compliance bladder. A significant correlation was noted for a pontine lesion and detrusor hyporeflexia, and for a cervical cord lesion and detrusor-sphincter dyssynergia. CONCLUSIONS: Detrusor hyporeflexia and detrusor-sphincter dyssynergia are indicative of a pontine and cervical spinal cord lesion, respectively. Thus, the lesion site in the central nervous system may be a major determinant of the type of bladder and urethral sphincter dysfunction. The high prevalence of emptying symptoms in Japanese patients may reflect the prevalence of detrusor hyporeflexia and detrusor-sphincter dyssynergia.

Adolescent↗
PubMed2003

Lower urinary tract symptoms in men and women without underlying disease causing micturition disorder: a cross-sectional study assessing the natural history of bladder function.

PURPOSE: We examined the influence of aging on bladder function in men and women. MATERIALS AND METHODS: Using the International Prostate Symptom Score questionnaire with an additional question on urinary incontinence lower urinary tract symptoms were evaluated in all outpatients who first visited our urological department from June 2001 to December 2002. In 550 of the 1,201 patients who completed the questionnaire any pathological conditions that might cause micturition disorder could not be detected with urological examinations. Symptom scores of these patients without underlying disease causing micturition disorder were the basis of this study. RESULTS: In men and women total and storage symptom scores but not the voiding symptom score increased significantly with age. In each age group total, storage and voiding symp-tom scores were not significantly different between men and women. Women 50 to 69 years old had significant higher incontinence scores than men of the same age, whereas a significant increase in the incontinence score with age was found only in men. The quality of life score increased with age in men but not in women. However, the 2 sexes did not significantly differ in quality of life score. CONCLUSIONS: Lower urinary tract symptoms, especially storage symptoms, showed age related alterations in the 2 sexes without any underlying disease causing micturition disorder. The prevalence of urinary symptoms was not different between men and women. Therefore, bladder function in each sex might be subject to a gender independent aging process.

Age Factors↗
PubMed2003

[Molecular biological researches of the lower urinary tract function].

Adrenergic alpha1 and beta receptors are present in the target organs of sympathetic nerve and they participate in the signal transduction mechanism of the lower urinary tract. Adrenergic alpha1 receptors are present in urethral and prostatic smooth muscles, and contract these muscles. Among these receptor subtypes, the alpha1-A receptor has the most important role, and mRNA expression of the corresponding alpha1-a subtype is predominant. In the human urinary bladder detrusor smooth muscle, the expression of adrenergic beta3 receptor subtype mRNA is predominant, and relaxation of detrusor smooth muscle is mediated mainly via beta3 receptor. Afferent nerve with lower threshold can easily transmit bladder sensation and takes an important role in the pathophysiology of urge urinary incontinence. Successful molecular cloning of vanilloid receptors, which are present in these afferent nerves, revealed that vanilloid receptors are ion-channels, sensitive for heat and pH, and termed VR1 and VRL1. Among purinergic receptors, ion channel type P2X3 receptor is found in afferent nerve fibers and plays some roles in the signal transduction of bladder sensation. In the near future, agonist for the adrenergic beta3 receptor and selective antagonists for VR1, VRL1, or P2X3 will possibly become drugs for pollakisuria and urge urinary incontinence.

Humans↗
PubMed2003

[Pharmacokinetics of paclitaxel and carboplatin in a hemodialysis patient with metastatic urothelial carcinoma--a case report].

A 69-year-old-man undergoing hemodialysis for 8 years developed metastatic urothelial carcinoma and received combination chemotherapy with paclitaxel and carboplatin. Paclitaxel 175 mg/m2 was given as a 3-hour intravenous infusion, and carboplatin was dosed to the area under the plasma concentration-time curve (AUC) of 5 mg.min/ml calculated according to the Calvert formula as a 30-minute intravenous infusion immediately after paclitaxel. Hemodialysis was started 1 hour after carboplatin, then their pharmacokinetics was determined in the patient. The AUC of paclitaxel and carboplatin were 15.2 and 64.56 micrograms.h/ml, respectively. The metastatic tumor size was reduced by more than 20% after 3 courses of this chemotherapy. Grade 3 neutropenia and grade 1 thrombopenia were observed. This is the first report that the combination of paclitaxel and carboplatin is feasible in a patient with metastatic urothelial carcinoma undergoing hemodialysis, with low toxicity and safety.

Aged↗
PubMed2002

Renography as a measure of renal and neobladder function in patients with ileal bladder substitution.

INTRODUCTION: Using renography, we evaluated the function of both the kidneys and neobladder of 20 patients who underwent ileal bladder substitution. METHODS: The patients were measured for renal and neobladder function with renography using 99mTc MAG3. Renal function was assayed in every renal unit using O'Reilly patterns. Voiding function was estimated using radioisotope counts for the reservoir. RESULTS: Thirty-two of 37 renal units had normal renograms. Five renal units showed non-obstructive renograms. The percentage of total residual urine (RU) in the reservoir was 30% and more in 6 patients, 10-30% in 8, and <10% in 6. In 7 of 12 patients, the data on estimated RU correlated with the data on measured RU. However, in 5 patients, the data on estimated RU increased more in quantity than the data on RU measured at another time. CONCLUSIONS: In patients with bladder substitution the functions of both the kidneys and neobladder could be evaluated in a single renography.

Aged↗
PubMed2002

Inhibition of c-Jun N-terminal kinase ameliorates apoptosis induced by hydrogen peroxide in the kidney tubule epithelial cells (NRK-52E).

BACKGROUND: Hydrogen peroxide (H2O2)-induced apoptosis has been shown to be involved in ischemic and toxic tubular damage. Recent studies have revealed that oxidative stress can activate c-Jun N-terminal kinase (JNK), and the oxidative stress-JNK pathway is an important apoptotic pathway of cells exposed to various stresses. The present study was designed to investigate JNK activation and the effects of the JNK pathway inhibition during H2O2-induced apoptosis in kidney epithelial tubule cells (NRK-52E). MATERIALS AND METHODS: NRK-52E cells were treated with 0-500 microM H2O2 and/or 100 microM quercetin (an inhibitor of the JNK pathway). Apoptosis was assessed by flow cytometry analysis and DNA ladder. JNK activity was assessed by the GST-c-Jun (1-169) binding/protein kinase assay. RESULTS: H2O2 induced apoptosis in NRK-52E cells in a concentration-dependent manner, which was demonstrated by the reduced DNA PI staining, externalization of phosphatidylserine and DNA ladder. Apoptosis induced by H2O2 was accompanied by JNK activation and up-regulated JNK activity. Quercetin treatment suppressed the JNK activity and ameliorated apoptosis induced by H2O2. CONCLUSIONS: H2O2 induced apoptosis in NRK-52E cells, which was associated with activation and up-regulation of JNK. Quercetin treatment could decrease JNK activity and ameliorate H2O2-induced apoptosis.

Animals↗
PubMed2002

[Prostaglandin].

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Alprostadil↗