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Biomedical subjects

K Shimamoto

Publications and source records attributed to K Shimamoto.

At least 469 records · Page 26Linked to original sources
PubMedDate not supplied

Radiologic diagnosis of hepatocellular carcinoma.

Recent developments in medical imaging technology and their clinical application for the diagnosis and management of hepatocellular carcinoma (HCC) are reviewed. Real-time ultrasound is effective for the screening of HCC in high-risk patients with liver cirrhosis. Information on blood flow is available by color Doppler or power Doppler technique. Dynamic computed tomography (CT) using a fast scanner and the modified contrast administration technique is useful for detection, differential diagnosis, and staging of HCC. Application of magnetic resonance (MR) imaging is increasing with rapid improvements in speed of image acquisition and resolution. Dynamic MR imaging and MR angiography have also been available. Diagnostic and interventional hepatic angiography are now performed less invasively, more safely, and more quickly with modern technologies of digital subtraction angiography (DSA) and catheters. CT during hepatic arteriography (CT arteriography) and arterial portography (CTAP) are used for evaluation of small focal nodules in the cirrhotic liver.

Carcinoma, Hepatocellular↗
PubMedDate not supplied

Suppression of the degradation of adenine nucleotides during ischemia may not be a sufficient mechanism for infarct size limitation by preconditioning.

Preconditioning is known to decelerate degradation of the tissue adenine nucleotides during ischemia and to delay ischemic myocardial necrosis. However, it is not known whether these two phenomena are related. To obtain an insight into this question, the present study examined whether adenosine and B2 receptor antagonists, which block the infarct size-limiting effect of preconditioning, modify the interstitial purine levels during preconditioning and subsequent sustained ischemia. In pentobarbital anesthetized open-chest rabbits, a microdialysis probe was placed in the territory of a branch of the left coronary artery, and perfused with Ringer solution. Preconditioning was performed with 5 min ischemia/5 min reperfusion. Dialysate adenosine and inosine were elevated from the baseline values of 0.064 +/- 0.011 and 0.329 +/- 0.044 microM to 0.189 +/- 0.069 and 4.106 +/- 1.451 microM, respectively during preconditioning, but their elevation during a subsequent 20 min of ischemia was significantly lower compared with that in the non-preconditioned myocardium. This suppression of the purine accumulation during ischemia by preconditioning was not abolished by 2 micrograms/kg of Hoe 140, a specific B2 receptor antagonist, or by 10 mg/kg of 8-phenyltheophylline, a non-selective adenosine receptor antagonist. Since the doses of Hoe 140 and 8-phenyltheophylline are sufficient to block the infarct size-limiting effect of preconditioning, the present results suggest that there is a dissociation between the suppression of adenine nucleotide degradation during ischemia by preconditioning and the enhancement of myocardial resistance against infarction. Thus, it is unlikely that a reduction of adenine nucleotide utilization by preconditioning is sufficient to protect the myocardium against ischemic necrosis.

Adenine Nucleotides↗
PubMedDate not supplied

Suppression of reperfusion arrhythmia by ischemic preconditioning in the rat: is it mediated by the adenosine receptor, prostaglandin, or bradykinin receptor?

The mechanism for the suppression of reperfusion arrhythmia by preconditioning (PC) remains unknown. This study aimed to examine the roles of the adenosine receptor, prostaglandin (PG), and bradykinin (BK) receptor in PC. Under pentobarbital anesthesia, the coronary artery of the rat was occluded for 5 min and then reperfused. In untreated controls, this protocol induced ventricular tachycardia (VT) in 100% of the rats and ventricular fibrillation (VF) in 60%. PC with 2 min ischemia/5 min reperfusion prior to the 5 min coronary occlusion significantly reduced the incidence of reperfusion VT and VF to 30% and 0%, respectively. This antiarrhythmic effect of the PC was not blocked when rats were pretreated with 8-phenyltheophylline (8-PT, 10 mg/kg), aspirin-DL-lysin (18 mg/kg), or a specific BK receptor antagonist, Hoe140 (20 nmol/kg). None of these agents alone significantly modified the incidence of reperfusion VT or VF. These results suggest that neither the adenosine receptor, endogenous PG, nor BK receptor play a major role in the mechanism of suppression of perfusion arrhythmias by PC in the rat heart.

Adrenergic beta-Antagonists↗
PubMedDate not supplied

Pseudoaneurysm of the superficial femoral artery in Behçet's disease with spontaneous thrombosis followed by CT angiography.

A 25-year-old man developed sudden pain and a pulsating mass in the left thigh. A diagnosis of Behçet's disease was made because of four major symptoms. Laboratory data indicated active inflammation. Emergency spiral computed tomographic angiography (CTA) showed an aneurysm of the left superficial femoral artery (SFA). Under steroid therapy, follow-up spiral CTA showed spontaneous occlusion of the aneurysm. In the active phase of arteritis, spiral CTA is useful for the diagnosis of arterial lesions to avoid the arterial puncture of conventional arteriography.

Adult↗