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Biomedical subjects

Keiichi Shishido

Publications and source records attributed to Keiichi Shishido.

5 recordsLinked to original sources

Ultrasound evaluation of dynamic responses of female pelvic floor muscles.

Ultrasound imaging of the pelvic floor carries diagnostically important information about the dynamic response of the pelvic floor muscles (PFM) to potentially incontinence-producing stress, which cannot be readily captured and assimilated by the observer during the scanning process. We presented an approach based on motion tracking quantitatively to analyze the dynamic parameters of PFM on the ano-rectal angle (ARA). Perineal ultrasonography was performed on 22 asymptomatic females and nine stress urinary incontinent (SUI) patients with a broad age distribution and parity. The ventral-dorsal and cephalad-caudad movements of the ARA were resolved and kinematic parameters, in terms of displacement, trajectory, velocity and acceleration, were analyzed. The results revealed the possible mechanisms of PFM responses to prevent the urine from incontinence in fast and stress events such as coughs. The statistical analyses showed that the PFM responses of the healthy subjects and the SUI patients are significantly different in both the supine and standing experiments.

Adult↗

Involvement of cyclic AMP-dependent and -independent mechanisms in the relaxation of rat detrusor muscle via beta-adrenoceptors.

We investigated the cAMP-dependent and -independent mechanisms of relaxation via beta-adrenoceptor in rat detrusor muscle with and without pre-contraction. A microdialysis technique was used to measure detrusor tension and cAMP level on the same detrusor tissue. In non-contracted tissue, isoproterenol, clenbuterol (beta2-adrenoceptor agonist) and FR165101, ((8S)-8-{[(2R)-2-(3-chlorophenyl)-2-hydroxyethyl]amino}-6,7,8,9-tetrahydro-5H-benzocyclohepten-2-yl)oxy]acetic acid hydrochloride (beta3-adrenoceptor agonist) relaxed detrusor muscle and cAMP levels also increased in a concentration dependent manner. SQ22536 (adenylyl cyclase inhibitor) markedly suppressed relaxation, suggesting that beta-adrenoceptor-mediated relaxation may be attributed mainly to cAMP-dependent mechanism. In high K+ pre-contracted tissue, although relaxation advanced in a concentration dependent manner, cAMP production reached a plateau at concentrations of more than 10(-7) M. SQ22536 had only a small inhibitory effect. However, large-conductance, Ca2+-activated K+ (BK(Ca)) channel inhibitors, charybdotoxin and iberiotoxin markedly suppressed relaxation. These results suggest that in addition to cAMP-dependent pathway, BK(Ca) channels are involved in the beta-adrenoceptor agonists-induced relaxation in pre-contracted detrusor muscle.

Adenine↗

[Retroperitoneal bronchogenic cyst: a case report].

A rare case of retroperitoneal bronchogenic cyst is presented. A 50-year-old man was referred to our hospital for an investigation of a retroperitoneal mass. Computed tomography and magnetic resonance imaging confirmed a retroperitoneal mass, about 4 cm in diameter, adjacent to the left kidney and spleen. On the basis of these imaging modalities, a definitive diagnosis of this mass could not be made. So, resection of the mass was performed. The removed mass was an unilocular cyst and filled with mucinous fluid. Histopathologically, the cyst wall was composed of a fibrovascular connective tissue containing mucus-secreting glands and cartilages and was lined by ciliated pseudostratified columnar epitherium. Thus, a diagnosis of bronchogenic cyst was made. Bronchogenic cysts are rare congenital anomalies of the primitive foregut and usually develop in the mediastinum and lung.

Bronchogenic Cyst↗