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Biomedical subjects

M Hirata

Publications and source records attributed to M Hirata.

At least 775 records · Page 43Linked to original sources
PubMedDate not supplied

Localized gallbladder carcinoma: sonographic findings.

Our study of color (seven cases) and contrast (three cases) Doppler results of seven cases with gallbladder carcinoma localized in the gallbladder wall (TNM stage T1) showed that the presence or absence of blood flow signals distinguishes gallbladder carcinoma in stage T1b (muscular involvement) from tumefactive biliary sludge and that injection of contrast medium markedly increased diagnostic confidence. Thus, when color Doppler sonography is ambiguous, contrast-enhanced Doppler sonography is the next line of investigation. However, actual color Doppler sonography is still not fully capable of displaying fine blood flow signals from gallbladder carcinoma in stage T1a (mucosal involvement), and greater Doppler sensitivity is mandatory for this purpose.

Carcinoma↗
PubMedDate not supplied

Ciliated hepatic foregut cyst: case report with an emphasis on US findings.

Ciliated hepatic foregut cyst (CHFC) is a rare mass, and its medical imaging findings are seldom reported. We present a histologically proven case of CHFC. The patient was asymptomatic, and a mass was found incidentally by sonography (US) in segment IV. The lesion was almost anechoic on fundamental US but filled with dense echoes with distinct posterior echo enhancement on second harmonic imaging. The lesion was avascular on color Doppler US and angiography. Thus, when US detects a mass in segment IV, the possibility of a CHFC should be considered regardless of the US results.

Cysts↗
PubMedDate not supplied

Segmental chronic cholecystitis: sonographic findings and clinical manifestations.

BACKGROUND: In chronic cholecystitis, the gallbladder (GB) wall is usually evenly involved, whereas marked segmental thickening of the GB wall (segmental cholecystitis) seldom is reported. We wanted to define its clinical manifestations and sonographic (US) findings. METHODS: We reviewed the clinical and US data of 13 cases and compared these results with those of 30 patients with chronic cholecystitis with evenly thickened GB walls (usual-cholecystitis group). RESULTS: (a) All cases of segmental cholecystitis showed the portion distal to the kinking to be markedly thickened. (b) The thickened portion corresponded to the fundus in three cases, the body and fundus in seven cases, and the fundus, body, and infundibulum in three cases; and the thickened distal portion contained many stones in 11 cases. (c) There was no difference in the maximal diameters of the GB walls between the segmental-cholecystitis group and the usual-cholecystitis group. However, there was a significant difference in the minimal diameters of the GB walls between groups. CONCLUSION: Knowledge of the US findings and clinical presentations of segmental cholecystitis can help in the development of appropriate diagnostic and therapeutic strategies.

Adult↗
PubMedDate not supplied

Primary carcinoid tumor of the liver: report of two cases with an emphasis on US findings.

Primary carcinoid tumor of the liver is rare, and its sonographic (US) findings have rarely been reported. We present two histologically proven cases. Both patients were asymptomatic and huge masses, found incidentally by US, were echogenic with many cystic areas. Lesions were markedly hypervascular on color Doppler US and angiography. Thus, primary carcinoid tumor of the liver should be considered when US detects this type of mass in asymptomatic patients.

Adult↗
PubMedDate not supplied

Mesenteric cyst: sonographic findings.

BACKGROUND: Mesenteric cyst (MC) is a relatively rare disease, and its sonographic characteristics have not been sufficiently analyzed. METHODS: We studied the sonographic findings of eight patients with MC, with attention paid to its size, shape, internal echoes, and especially the presence or absence of lateral shadowing and the mode of back echoes. In four cases, the sound velocity and acoustic impedance of cystic fluid were also measured. The mode of blood flow was evaluated by color Doppler sonography. RESULTS: Six cases showed an oval or comma-shaped mass. Internal echoes were present in six cases, and two of them showed a pseudosolid pattern. In these cases, M-mode sonography confirmed the movement of these internal echoes. Only one case showed a posterior echo enhancement, and no case showed lateral shadowing. Sound velocity measured in four cases was 1,515-1,537 m/s, with an acoustic impedance of 1.550-1.576 kg/m2/s. No blood flow signals were obtained from the lesion. CONCLUSION: MC exhibits so many patterns on ultrasound that we should consider the possibility of MC when encountering an avascular oval mesenteric mass.

Adolescent↗
PubMedDate not supplied

Macronodular hepatic deformity on normal liver.

BACKGROUND AND METHODS: Macronodular hepatic deformity on normal liver is very rare. We present nine such cases and try to define the characteristic clinical and ultrasound (US) findings. RESULTS: In the left lobe, the lateral segment was replaced by multiple nodules and the medial segment was very atrophied and irregularly shaped. Compared with the left lobe, the right lobe showed very few abnormalities except for segment 6, which showed a macronodular deformity. These nodules, regardless of diameter or lobe, showed a relatively homogeneous internal structure and were isoechoic relative to the surrounding hepatic parenchyma. These multinodular changes on US corresponded to multiple regenerative nodules identified at laparoscopic evaluation. On color Doppler US and angiography, the major intrahepatic vessels were patent in all cases. CONCLUSION: Although relatively rare, the macronodular hepatic deformity on normal liver collected in our series showed a characteristic appearance by US. A good understanding of its characteristics may help sonographers in differentiating it from other, more common hepatic deformities.

Adult↗
PubMedDate not supplied

Choledochal cyst due to anomalous pancreatobiliary junction in the adult: sonographic findings.

BACKGROUND: Adult cases of choledochal cyst due to anomalous pancreaticobiliary duct junction have been rarely reported. At present, sonography (US) is the first tool for diagnosing biliary disorders. The aim of this study was to reevaluate the US findings of choledochal cysts due to anomalous pancreaticobiliary duct junction in adults. METHODS: We reviewed the clinical manifestations and US findings of 12 such adult cases confirmed by endoscopic retrograde cholangiopancreatic ductography (ERCP). Patients were assigned to three groups: (a) associated with biliary carcinoma (two cases), (b) associated with choledocholithiasis (one case), and (c) not associated with other abdominal diseases (nine cases). RESULTS: Patients in group c were asymptomatic, and the lesions were detected incidentally detected by US. In contrast, patients in group a sought medical care because of symptoms such as jaundice and those in group b sought medical attention because of abdominal pain. The diameter of a dilated bile duct on US was considerably less than that of ERCP (ERCP: 26-58 mm, mean = 37.6 mm; US: 13-32 mm, mean = 21.8 mm). Its diameter changed significantly under probe compression when the dilated bile duct took a purely cystic form but changed very little when it took a tubular form. CONCLUSION: Unlike cases in children, adult cases of choledochal cyst are generally asymptomatic. Careful US observation of the bile duct is thus expected to detect asymptomatic adult choledochal cysts cases. Cyst diameter can change significantly under probe compression, so it is important not to compress the bile duct during routine US examination.

Adult↗
PubMedDate not supplied

Reduced conduction function in central nervous system by 2,5-hexanedione.

In order to examine the involvement of the central nervous system (CNS) following administration of 2,5-hexanedione (2,5-HD) in rats, the present experiment was conducted using the auditory brainstem response (ABR) and somatosensory-evoked potentials (SEPs). Nine male Wistar rats were given 2,5-HD subcutaneously at 350 mg/kg/day, five days a week for three weeks. For the control group, nine male rats were employed. One week after the last administration, ABRs were measured from the scalp with subcutaneous needle electrodes under pentobarbital anesthesia. Click sounds of 61 and 86 dB sound pressure level were used in ABR measurement (61dB-ABR and 86dB-ABR, respectively). The SEP evoked by stimulation at the forepaw and the medulla oblongata (SEP and SEP-M) were recorded from the surface of the cerebral cortex using screw electrodes under immobilization. The significant findings observed in 2,5-HD-treated rats included: 1) delayed latencies of the Ist, IIIrd, IVth and Vth components of the 61dB-ABR and the Ist, IInd, IIIrd and Vth components of the 86dB-ABR; 2) increased interpeak latencies (IPLs) between III-V and I-V of the 61dB-ABR; 3) delayed latencies of the P1 and N1 components of the SEP and the N1 component of the SEP-M. The delays of IPL-III-V of the 61dB-ABR and the N1 component of the SEP-M were considered to reflect conduction disorders of the auditory and somatosensory afferent pathway in the CNS, respectively. Thus, the ABR may be a sensitive method to detect disorders in the CNS produced by neurotoxic substances.

Animals↗
PubMedDate not supplied

Irreversible inhibition of Ca2+ release in saponin-treated macrophages by the photoaffinity derivative of inositol-1, 4, 5-trisphosphate.

D-myo-inositol-1,4,5-trisphosphate (InsP3) is a putative intracellular second messenger for the mobilization of Ca2+ from intracellular stores, in particular, the endoplasmic reticulum. Specific binding sites on the endoplasmic reticulum may participate in the InsP3-induced release of Ca2+ from the Ca2+ pool. To examine the specific binding sites on the endoplasmic reticulum, we synthesized an arylazide derivative of InsP3 for photoaffinity labelling; InsP3 coupled to p-azidobenzoic acid (InsP3-pAB) using N,N'-carbonyldiimidazole (CDI) was obtained at a 9-11% yield. Here, we report that InsP3-pAB, but not an arylazide derivative of inositol-1,4-bisphophate (Ins(1,4)P2), causes the irreversible inhibition of InsP3-induced release of Ca2+ in saponin-permeabilized photo-irradiated macrophages. The irreversible inhibition by InsP3-pAB after photo-irradiation was prevented by a 10-fold excess of unmodified InsP3.

Affinity Labels↗
PubMedDate not supplied

Effect of 2-phenylaminoadenosine (CV-1808) on ischemic ST-segment elevation in anesthetized dogs.

The effect of 2-phenylaminoadenosine (CV-1808) against myocardial ischemia was studied in anesthetized dogs. During intravenous infusion of CV-1808 (0.25 and 0.5 microgram/kg/min for 10 min) the ST-segment elevation in the epicardial ECG induced by a 5-min occlusion of a coronary arterial branch was occasionally enhanced in association with cardiac acceleration. In a dose of 0.5 microgram/kg/min, the agent inhibited the ST elevation 30 and 60 min after administration. The same dose did not change myocardial blood flow in the ischemic area despite significant systemic hypotension. In hearts with continuous coronary occlusion, CV-1808 (0.3 and 1.0 microgram/kg, i.v. bolus) increased the retrograde blood flow from the ischemic area immediately after administration, suggesting a collateral vasodilating action. Nifedipine (0.5 and 2.5 microgram/kg/min, i.v. for 10 min) and nitroglycerin (0.5 and 5.0 microgram/kg/min, i.v. for 10 min) had no influence on the ischemic ST-segment elevation, while a significant inhibition was seen with propranolol (0.5 mg/kg, i.v.). A moderate hypotension was induced by CV-1808, nifedipine, and nitroglycerin, while a significant reduction in cardiac function was seen after dosing with propranolol.

Adenosine↗
PubMedDate not supplied

Inhibition of coronary circulatory failure and thromboxane A2 release during coronary occlusion and reperfusion by 2-phenylaminoadenosine (CV-1808) in anesthetized dogs.

The effects of potent coronary vasodilator, 2- phenylaminoadenosine (CV-1808), on coronary circulatory failure and thromboxane (TX) A2 release were studied during coronary occlusion (for 60 min) and subsequent reperfusion (for 60 min) in anesthetized dogs. During coronary reperfusion, reactive hyperemic response was attenuated, and coronary conductance decreased gradually with time, suggesting coronary circulatory failure. TXA2 release was markedly increased, as demonstrated by contraction of rabbit aortic strips perfused with coronary venous blood draining the ischemic myocardium, and by increased release of radioimmunologically assayable TXB2. CV-1808 (0.25 microgram/kg/min i.v. infusion throughout the experimental period, starting 10 min before coronary occlusion) inhibited coronary circulatory failure and TXA2 release. TXA2 synthetase of horse platelet microsomes was not significantly inhibited (-11.6 +/- 2.1%) by 10(-4) M CV-1808. The compound (10(-5) and 10(-4) M) inhibited collagen-induced TXB2 formation in a dose-dependent manner (-23.0 +/- 9.0 and -74.0 +/- 15.0%, respectively), but not arachidonic acid-induced TXB2 formation by dog platelets, suggesting that CV-1808 inhibited phospholipases. Myocardial infarct size determined 60 min after reperfusion was significantly reduced by CV-1808. Thus, CV-1808 appeared to be effective for salvaging ischemic myocardium. The effect might be related to improvement of coronary circulation and inhibition of release of vasoactive substances, including TXA2, from the ischemic myocardium.

Adenosine↗
PubMedDate not supplied

Protective effect of a novel thromboxane synthetase inhibitor, CV-4151, on myocardial damage due to coronary occlusion and reperfusion in the hearts of anesthetized dogs.

The protective effect of a novel thromboxane (TX) synthetase inhibitor, (E)-7-phenyl-7-(3-pyridyl)-6-heptenoic acid (CV-4151), on myocardial damage due to an ischemic episode and reperfusion was investigated in anesthetized, open-chested dogs. The left anterior descending coronary artery (LAD) was occluded for 60 min and subsequently reperfused for 60 min. CV-4151 was infused i.v. at a dose of 1 mg/kg over a 10-min period starting 20 min before the LAD occlusion. The agent had no acute hemodynamic effects. Within 30 min after LAD occlusion, 15.6-33.3% of dogs experienced ventricular fibrillation (VF); CV-4151 had no significant effect on the incidence of VF. After reperfusion, the frequency of ventricular extrasystoles (PVCs) was markedly increased, and 33.3% (9 of 27 dogs) died of VF in the control group. CV-4151 suppressed the exaggerated PVCs, and the incidence of VF in the group was 0% (0/18, p less than 0.05). Myocardial infarct size determined 60 min after reperfusion by a p-nitroblue tetrazolium (p-NBT) staining technique was significantly reduced by CV-4151. Increase in TXB2 release into the great coronary vein during reperfusion was completely inhibited by CV-4151, whereas release of 6-keto-PGF1 alpha tended to increase during occlusion and reperfusion. Thus, the ratio of 6-keto-PGF1 alpha to TXB2 levels was significantly increased throughout occlusion and reperfusion periods. These results suggest that inhibition of TXA2 synthesis is beneficial for protection of the myocardium during reperfusion from ischemic damage.

6-Ketoprostaglandin F1 alpha↗
PubMedDate not supplied

Extra-articular wide tumor resection and limb reconstruction in malignant bone tumors invading the knee joint.

We demonstrate our procedure of extra-articular wide tumor resection and its clinical outcome. The knee joint including the femorotibial, patellofemoral and the proximal tibiofibular joints was totally resected without any view of articular cartilage and synovium. The resected limb was reconstructed with endoprosthesis of the knee joint. The average score of the limb function evaluated by ISOLS criteria was 69.3% in all patients. The limb function of these patients was almost the same as that of the patients who received the intra-articular procedure. The procedure of extra-articular resection was theoretically necessary and clinically practical.

Arthroplasty, Replacement, Knee↗
PubMedDate not supplied

Bone reaction induced by femoral stem of titanium alloy endoprosthesis for malignant bone tumors at the distal femur.

We demonstrated radiological evaluations after limb salvage surgery with an uncemented titanium endoprosthesis possessing a rotating hinge-type knee joint for 7 patients with malignant bone tumors at the distal femur. Although radiographically, cortical hypertrophy and new bone formation at the junction between implant and cortex appeared in all cases, there was a small quantity of subsidence of the implant in all cases. Loosening of the stem was found in 2 patients at 4 and 9 years after surgery. However, after revision surgery, the function restored as before. The latest average functional score according to the system of the International Society of Limb Salvage was good, being 73%.

Adolescent↗
PubMedDate not supplied

Two cases of secondary angiosarcoma arising from fibrous dysplasia.

Angiosarcoma associated with fibrous dysplasia is very rare. We have recently experienced two cases of angiosarcoma that secondarily arose from fibrous dysplasia. The first patient, a 55 year-old man, had noticed a deformity in the right upper arm since he was five years old. At the age of 25 years, polyostotic fibrous dysplasia was diagnosed by X-ray examination. The patient complained of swelling and pain around the left shoulder. The diaphysis of the humerus was mostly non-observable due to severe bone destruction by tumor invasion and there was a large soft tissue tumor. Biopsy examination revealed grade II or III hemangioendothelioma with typical histologic findings of fibrous dysplasia. After interscapulothoracic amputation for wide tumor resection, he died of DIC. Autopsy revealed multiple liver metastatic lesions of angiosarcoma. The second patient was a 66-year-old woman. She presented with a pathological fracture in the right tibia, due to an osteolytic lesion with cortical bone swelling and thinning. The histologic diagnosis was fibrous dysplasia without any sarcomatous changes. However, after a 3-time recurrence, angiosarcoma arose from the same lesion. She is now still alive with disease-free period of 6.5 years after amputation.

Aged↗