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Biomedical subjects

K Yoshimitsu

Publications and source records attributed to K Yoshimitsu.

At least 73 records · Page 4Linked to original sources
PubMed1979

Prolonged pseudoaldosteronism induced by glycyrrhizin.

We describe the natural recovery from the aggravated hypertension, hypokalemia and suppression of the renin-aldosterone axis after the glycyrrhizin discontinuation in two mild hypertensive women aged 71 and 68 years, who had been administered 273 to 546 mg glycyrrhizin daily for 1.5 and 6 months, respectively, for the treatment of liver disease. About one month after the glycyrrhizin discontinuation, acceleration of hypertension, hypokalemia and suppression of the renin-aldosterone system still continued in both patients. At this stage, sodium restriction resulted in the normalization of blood pressure with weight loss and the subsequent sodium repletion produced a rapid increase in blood pressure to hypertensive levels observed before sodium restriction, with weight gain. Plasma renin activity and plasma aldosterone were low and did not respond to sodium restriction. Inappropriately excessive amounts of potassium were also excreted in the presence of hypokalemia. About one and a half months later, the improvements of aggravated hypertension, hypokalemia and suppressed renin-aldosterone system gradually occurred in both patients. Sodium restriction performed about three months later in case 2 no longer produced the changes in blood pressure and body weight. Plasma renin activity and plasma aldosterone responded subnormally to sodium restriction. These results demonstrate that both patients had a prolongation of the syndrome resembling primary aldosteronism except the low plasma aldosterone level about one month after the glycyrrhizin discontinuation. The possible mechanisms by which this prolongation was caused are discussed.

Aged↗
PubMed1976

[Effect of somatostatin on pancreatic endocrine--experiment by somatostatin infusion into the pancreaticoduodenal artery in dogs--(author's transl)].

The direct inhibitory action of somatostatin (cyclized SRIF) on the pancreatic endocrine function was investigated by a technique using pancreaticoduodenal arteriovenous system in vivo. Somatostatin was infused for 20 minutes at a speed of 2.5 mug/minute into the superior pancreaticoduodenal vein and femoral artery were measured before and every 5 minutes throughout the experiment for 30 minutes. The results were compared with those obtained from the control experiment which was carried out in the same time schedule under infusion of physiologic saline solution instead of somatostatin. Next, the effect of somatostatin on the glucose-induced insulin release from the pancreas was also evaluated. The following findings were obtained. (1) Somatostatin infused at a speed of 2.5 mug/minute into the superior pancreaticoduodenal artery caused a statistically significant inhibition of plasma levels of IRI and IRG and also pancreatic output of these hormones. With the sessation of somatostatin infusion an abrupt rise of the hormones were seen. This "rebound" phenomenon was more pronounced in insulin secretion than in glucagon. No significant changes in the plasma glucose levels in either the pancreaticoduodenal vein or the femoral artery throughout the experiment were found. (2)During infusion of somatostatin at a speed of 1.25 mug/minute, insulin response to glucose injected into the pancreaticoduodenal artery in a small dose, as well as having no effect on the plasma glucose level in systemic circulation, was also significantly inhibited. From these findings obtained by direct experiment using the pancreaticoduodenal arterio-venous system, it was confirmed that somatostatin exhibits a direct inhibitory action on pancreas endocrine in a very low concentration in vivo, and it was suggested that this action might be partly due to a reduction in pancreatic circulation.

Animals↗
PubMedDate not supplied

Unsuppressed fat in the right anterior diaphragmatic region on fat-suppressed T2-weighted fast spin-echo MR images.

The authors retrospectively evaluated magnetic resonance images of the abdomen obtained in 52 consecutive patients. All cases included fast spin-echo (FSE) T2-weighted images acquired with a frequency-selective fat saturation technique. All imaging was performed with a 1.5-T unit. In 42 patients (81%), fat was not suppressed in the right anterior diaphragmatic region on the T2-weighted FSE images with fat suppression. In 11 (26%) of these 42 patients, subcutaneous fat adjacent to the unsuppressed anterior diaphragmatic fat was well suppressed. Hence, the fat in the diaphragmatic region mimicked fluid or peritoneal implants. The cause of the artifact appears to be the juxtaposition of liver, fat, and lung parenchymal air within a small anatomic space, creating a localized inhomogeneity of the magnetic field and susceptibility effects. Radiologists should be aware of this phenomenon to prevent confusion of an artifact with fluid or neoplasms.

Abdomen↗
PubMedDate not supplied

MR prediction of benign and malignant vertebral compression fractures.

We reviewed spinal MR images of 58 patients with 98 compressed vertebrae. Benign (47 vertebrae) or malignant (51 vertebrae) etiology was established by biopsy or radiologic follow-up. Compressed vertebrae were analyzed for presence and characteristics of signal abnormality, altered vertebral contour, Schmorl's nodes, pedicular involvement, and contrast uptake. Statistical analysis was performed. Diffuse and homogeneous decrease in signal intensity on T1-weighted images, convex vertebral contour, involvement of the pedicles, and a lumbar location were more frequently observed in malignant fractures (P < .01). A thoracic location, lack of signal change, or a band-like abnormality and absence of pedicular involvement or contour abnormality characterized benign fractures (P < .01). Schmorl's nodes and enhancement did not help establish a diagnosis. When a constellation of MR criteria are applied, the accuracy of the diagnosis of malignant and benign vertebral compression fractures may reach 94%.

Adult↗
PubMedDate not supplied

MR signal intensity changes in hepatic parenchyma with ductal dilation caused by intrahepatic cholangiocarcinoma.

MR images of the liver in 13 patients with surgically proven intrahepatic cholangiocarcinoma were reviewed retrospectively and correlated to the histologic analysis of surgical specimens. We paid special attention to the peripheral liver tissue with ductal dilation but without tumorous involvement. High signal intensity was observed in the hepatic parenchyma with ductal dilation on T1-weighted spin-echo images (8 of 12) and spoiled gradient-recalled echo images (seven of seven), as compared with the contralateral hepatic lobe without duct dilation. The high signal intensity was not suppressed with fat saturation and showed enhancement after administration of contrast (11 of 12). Concurrent portal venous obstruction did not have significant effect on these findings (P < .05). Correlation with pathologic specimens suggested that this enhancement was associated with periportal fibrosis. The etiology of the high signal intensity on unenhanced spin echo or gradient-recalled T1-weighted image remains unclear. Radiologists should recognize these findings and should distinguish these from tumor involvement or the arterial buffer response caused by portal venous obstruction.

Bile Duct Neoplasms↗
PubMedDate not supplied

Dynamic MRI of the gallbladder lesions: differentiation of benign from malignant.

Forty-nine pathologically proven gallbladder lesions were evaluated in 45 patients using dynamic MRI with a spoiled gradient pulse sequence (SPGR), to access the ability of this technique to differentiate benign from malignant gallbladder lesions. The studies were reviewed retrospectively. Signal intensity of the lesions were measured. Twenty-one malignant and 28 benign lesions were classified into three categories: polypoid, diffuse wall thickening, and exophytic. Early and delayed enhancement patterns were evaluated. For the polypoid masses, malignant lesions (n = 9) demonstrated early and prolonged enhancements, whereas benign lesions (n = 14) had early enhancement with subsequent washout (P < .05). For diffuse gallbladder wall thickening, malignant lesions (n = 6) demonstrated early and prolonged enhancement and benign lesions (n = 14) showed relatively slow, prolonged enhancement (P < .05). The exophytic masses (n = 6) all were malignant and demonstrated early and prolonged enhancement. Dynamic MRI can help differentiate benign from malignant gallbladder lesions.

Adult↗
PubMedDate not supplied

Multiple intrahepatic portosystemic venous shunts: treatment by portal vein embolization.

A rare case of symptomatic, multiple, intrahepatic, portosystemic venous shunts which was treated by portal vein embolization after surgical cannulation is reported. The patient, having suffered from hepatic encephalopathy, improved dramatically after embolization. This method might be the only choice of therapy for intrahepatic portosystemic shunts of this kind.

Embolization, Therapeutic↗
PubMedDate not supplied

Coil embolization of arterioportal fistula that developed after partial gastrectomy.

A 51-year-old man suffered from bleeding esophageal varices. He had undergone partial gastrectomy for gastric cancer 1 year before. An extrahepatic arterioportal fistula and resultant portal hypertension were found. We successfully performed transarterial embolization of the fistula using stainless steel coils. Portal hypertension improved dramatically.

Angiography↗
PubMedDate not supplied

Measurement of the apparent diffusion coefficient in intraductal mucin-producing tumor of the pancreas by diffusion-weighted echo-planar MR imaging.

BACKGROUND: We investigated whether diffusion-weighted echo-planar magnetic resonance (MR) imaging can help differentiate intraductal mucin-producing tumors of the pancreas from other cystic lesions. METHODS: Diffusion-weighted echo-planar MR imaging was performed in patients with mucin-producing tumors (n = 19), pseudocysts (n = 9), chronic pancreatitis with diffuse main pancreatic dilatation (n = 5), and serous cystadenomas (n = 2). Images were obtained with diffusion sensitizing gradients of 30, 300, and 900 s/mm2. The apparent diffusion coefficient (ADC) was calculated. RESULTS: The mean (+/- standard deviation) ADCs of mucin-producing tumors (2.8 x 10(-3) mm2/s +/- 1.0 x 10(-3)), pseudocysts (2.9 x 10(-3) mm2/s +/- 1.2 x 10(-3)), dilated main pancreatic duct in chronic pancreatitis (3.3 x 10(-3) mm2/s +/- 1.2 x 10(-3)), serous cystadenomas (2.9 x 10(-3) and 2.6 x 10(-3) mm2/s), and cerebrospinal fluid (3.5 x 10A(-3) mm2/s +/- 1.1 x 10(-3)) were not statistically different. CONCLUSION: It is difficult to differentiate between mucin-producing tumors and other cystic lesions by ADC measurements when using diffusion-weighted echo-planar MR imaging.

Adult↗
PubMedDate not supplied

Gallbladder torsion: case report.

Torsion of the gallbladder (GB) is a rare, acute abdominal condition. The treatment of choice is cholecystectomy. Even with recent advances in radiologic imaging modalities, it is difficult to make a correct preoperative diagnosis of GB torsion. We report a case of GB torsion with a retrospective review of the radiologic findings of magnetic resonance imaging, computed tomography, and ultrasonography. Those findings were compared with the histopathologic findings of the surgical specimen. The radiologic findings in our case were useful for making a preoperative diagnosis of GB torsion. We postulate the characteristic magnetic resonance findings and discuss discrepancies in the evaluations of the GB wall.

Adult↗
PubMedDate not supplied

Fat in liver metastasis from renal cell carcinoma detected by chemical shift MR imaging.

A case with liver metastasis from papillary renal cell carcinoma (RCC) is presented, in which intratumoral fat was detected on dual-echo chemical shift magnetic resonance imaging (MRI). The preoperative chemical shift MR image of the primary RCC also suggested the presence of intratumoral fat. Liver metastasis from fat-containing RCC should be included in the differential diagnosis of fat-containing liver masses as observed on chemical shift MRI.

Adipose Tissue↗
PubMedDate not supplied

Fat detection in gallbladder carcinoma with extensive xanthogranulomatous change demonstrated by chemical shift MR imaging.

We present a case of gallbladder carcinoma, in which fat was detected on dual-echo chemical shift magnetic resonance imaging (MRI). Histologic analysis showed poorly differentiated adenocarcinoma associated with massive xanthogranulomatous change. Sudan IV staining successfully confirmed the presence of fat within the interstitial histiocytes. Although rare, gallbladder carcinoma with xanthogranulomatous change should be included in the differential diagnosis of fatty tumor involving the region of the liver as observed on chemical shift MRI.

Adenocarcinoma↗
PubMedDate not supplied

Bilateral ovarian leiomyomas: CT and MRI features.

We recently treated a 21-year-old woman with leiomyomas arising from the bilateral ovaries, a very rare condition. On magnetic resonance imaging, more than half of the left adnexal mass showed low signal intensity on T2-weighted images and good enhancement by gadolinium-DTPA, and the remaining part showed high signal intensity on T2-weighted images, so the lesions initially were diagnosed as ovarian fibromas or as thecomas with a certain degree of degeneration. Pathologic examination of the excised tumors proved that they were bilateral ovarian leiomyomas; in addition, the tumor from the left side showed hemorrhagic and myxoid changes with torsion of 180 degrees.

Adult↗
PubMedDate not supplied

Abdominal cystic tumors containing small amount of fat in the septa: report of two cases.

We present two cases of abdominal cystic tumors containing small amounts of fat in their septa. Although the final pathologic diagnoses of these tumors were cystic lymphangioma and angiomatosis, the computed tomographic and magnetic resonance imaging features were almost identical and indistinguishable; a purely cystic mass around the region of the pancreas head associated with little mass effect on the surrounding organs and septa containing a radiologically evident fatty component. Radiologists should be aware of these two entities as differential diagnoses of abdominal cystic masses containing small amounts of septal fat.

Abdominal Neoplasms↗
PubMedDate not supplied

Metastatic adrenal tumor from clear-cell renal cell carcinoma: a pitfall of chemical shift MR imaging.

We present a case of adrenal metastasis from clear-cell renal cell carcinoma in which presence of a small amount of fat was shown on chemical shift gradient-echo magnetic resonance imaging. Radiologists should be aware that signal loss of the adrenal tumor on out-of-phase gradient-echo images does not always suggest the diagnosis of benign adenoma, particularly in patients with a history of renal cell carcinoma.

Adenocarcinoma, Clear Cell↗
PubMedDate not supplied

Sclerosed hemangioma of the liver.

We report the radiologic findings of sclerosed hemangioma (SH), a rare variant of hepatic hemangioma. Dynamic contrast-enhanced computed tomography showed a hypodense mass in the liver with delayed enhancement. T2-weighted magnetic resonance imaging showed the mass as hypointense in relation to cerebrospinal fluid. The final diagnosis of SH was made pathologically. Although SH is rare, understanding its radiologic appearance is important to avoid unnecessary surgery and should be included in the differential diagnoses of hepatic lesion with delayed enhancement.

Aged↗