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Biomedical subjects

K Masuda

Publications and source records attributed to K Masuda.

At least 937 records · Page 52Linked to original sources
PubMedDate not supplied

Radiologic diagnosis of adenomyomatosis of the gallbladder: comparative study among MRI, helical CT, and transabdominal US.

PURPOSE: The goal of this work was to evaluate the diagnostic accuracy of transabdominal ultrasound (US), helical CT, and MRI in the diagnosis of adenomyomatosis (ADM) of the gallbladder. METHOD: Twenty patients with surgically proven ADM were included, all of whom underwent preoperative US, helical CT with 3 mm collimation, and MRI with half-Fourier rapid acquisition with relaxation enhancement (RARE). All images were retrospectively reviewed by two radiologists, and the presence of ADM was assessed at three compartments (neck, body, and fundus) of the organ. Receiver operating characteristic analysis was performed, and sensitivity, specificity, and accuracy were calculated for each modality. RESULTS: The A z values (area under the curve) for MRI, helical CT, and US were 0.98, 0.85, and 0.72 for the Reader 1, respectively, showing no statistically significant interobserver difference in any of the three modalities. MRI showed a significantly higher A z value than helical CT or US (p < 0.1). The accuracies of MRI, helical CT, and US were 93, 75, and 66%, respectively. CONCLUSION: Among the three modalities tested, MRI with half-Fourier RARE sequence was the most accurate for diagnosing ADM.

Adenomyoma↗
PubMedDate not supplied

Noninvasive estimation of cardiac systolic function using continuous-wave Doppler echocardiography in dogs with experimental mitral regurgitation.

OBJECTIVE: To evaluate the feasibility of noninvasive estimation of cardiac systolic function using transthoracic continuous-wave Doppler echocardiography in dogs with mitral regurgitation. PROCEDURE: Seven mongrel dogs with experimental mitral regurgitation were used. Left ventriculography and measurement of pulmonary capillary wedge pressure were performed under inhalational anaesthesia. A micromanometer-tipped catheter was placed into the left ventricle and transthoracic echocardiography was carried out. The peak rate of left ventricular pressure rise (peak dP/dt) was derived simultaneously by continuous-wave Doppler and manometer measurements. The Doppler-derived dP/dt was compared with the catheter-measured peak dP/dt in the dogs. RESULTS: Classification of the severity of mitral regurgitation in the dogs was as follows: 1+, 2 dogs; 2+, 1 dog; 3+, 2 dogs; 4+, 1 dog; and not examined, 1 dog. We were able to derive dP/dt from the transthoracic continuous-wave Doppler echocardiography in all dogs. Doppler-derived dP/dt had a significant correlation with the catheter-measured peak dP/dt (r = 0.90, P < 0.0001). CONCLUSION: It was demonstrated that transthoracic continuous-wave Doppler echocardiography is a feasible method of noninvasive estimation of cardiac systolic function in dogs with experimental mitral regurgitation and may have clinical usefulness in canine patients with spontaneous mitral regurgitation.

Animals↗
PubMedDate not supplied

Spectrum of CT findings in nonmalignant disease of the adrenal gland.

Computed tomography (CT) plays a leading role in the evaluation of nonmalignant disease of the adrenal gland. CT is highly accurate in the localization of adrenal masses in patients with diseases associated with hyperfunctioning adrenal glands such as Cushing syndrome and Cushing disease, Conn syndrome, adrenal tumors leading to virilization or feminization, and pheochromocytomas. CT permits a specific diagnosis of acute or subacute adrenal hematoma and myelolipoma. Hematomas are round to oval and have increased attenuation (50-90 HU) that decreases on follow-up CT scans. Myelolipomas typically manifest as a well-defined suprarenal mass with an attenuation of-30 to -115 HU. Adrenal cysts are usually round to oval and manifest as a hypoattenuating mass with a smooth, thin wall. CT is useful in the evaluation of patients with Addison disease, particularly the subacute form secondary to tuberculosis or disseminated histoplasmosis. Findings typically include bilateral adrenal enlargement with a central necrotic area of hypoattenuation and peripheral enhancement. Thin-section unenhanced CT permits accurate measurement of attenuation and can be used to differentiate adrenal adenoma from metastasis in a cancer patient with an indeterminate mass: Attenuation of 10 HU or less usually indicates adenoma rather than cancer. If the mass is found incidentally at contrast material-enhanced CT, delayed scans obtained as early as 5-15 minutes after intravenous administration of contrast material appear to have comparable accuracy.

Addison Disease↗
PubMedDate not supplied

Pitfalls in MR cholangiopancreatographic interpretation.

Magnetic resonance (MR) cholangiopancreatography (MRCP) is widely used in the evaluation of pancreatobiliary disorders. However, numerous related pitfalls may simulate or mask pancreatobiliary disease. Maximum-intensity-projection (MIP) reconstructed images completely obscure small filling defects and may demonstrate respiratory motion artifacts. T2 weighting may vary with different MR imaging sequences and influence MRCP findings. Incomplete imaging may create confusion regarding ductal anatomy or disease. Furthermore, MRCP yields only static images and thus may fail to depict various anomalies. Limited spatial resolution makes differentiation between benign and malignant strictures with MRCP alone extremely difficult. Susceptibility artifacts may be caused by metallic foreign bodies or gastric-duodenal gas. Fluid accumulation may produce a pseudolesion or pseudostricture, although changing the imaging angle or section thickness may be helpful. Pneumobilia may be misinterpreted as bile duct stones, and true stones may be overlooked. Pulsatile vascular compression can cause pseudo-obstruction of the bile duct. Use of both source and MIP reconstructed images obtained from different angles can help avoid cystic duct-related pitfalls. Repeat MRCP or conventional MR imaging can help avoid pitfalls related to the periampullary region. Segmental collapse of the normal main pancreatic duct may be misinterpreted as stenosis, but administration of secretin is helpful. An awareness of these pitfalls and possible solutions is crucial for avoiding misinterpretation of MRCP images.

Biliary Tract↗
PubMedDate not supplied

Effects of different intensity endurance training on the capillary network in rat skeletal muscle.

Effects of low- and high-intensity endurance training on the capillary luminal diameter and number were studied morphometrically in the rat plantaris muscle. Male Wistar-Imamichi rats were divided into three groups: sedentary control group (Cont, n = 9), low-intensity (running speed of 20 m/min) training group (T-20, n = 8) and high-intensity (running speed of 40 m/min) training group (T-40, n = 7). Rats in both training groups were subjected to each treadmill running program for 60 min/day, 5 days/week for 9 weeks. After 9 weeks of training, citrate synthase activity significantly increased in T-40 compared with Cont, but did not change in T-20. All morphometric parameters with respect to capillary and muscle fiber area were determined in the perfusion-fixed plantaris muscle. The mean muscle fiber areas in both T-20 and T-40 were similar to that in Cont. The capillary-to-fiber ratios were significantly higher in T-20 (2.28 +/- 0.06) and T-40 (2.29 +/- 0.06) than in Cont (2.00 +/- 0.07). The number of capillaries with a small luminal diameter (2-4 microns) was significantly higher in T-20 than in Cont. In contrast, T-40 had a significantly higher number of capillaries with a large luminal diameter (8-10 microns) compared with Cont. This study indicates that endurance training induces changes in the capillary luminal diameter as well as capillary number, and that the adaptive response of the capillary luminal diameter to endurance training depends on the training intensity.

Animals↗
PubMedDate not supplied

Cerebral primitive neuroectodermal tumor in an adult male. A case report.

BACKGROUND: Primitive neuroectodermal tumors (PNETs) are very rare. Malignant tumors of the cerebrum in young individuals are composed predominantly of undifferentiated cells, with moderate differentiation along either neuronal or glial lines. To our knowledge, cerebral PNETs in adults are extraordinarily rare and have been reported in only 11 cases, with little cytologic documentation in the literature. The cytopathologic, immunohistochemical and ultrastructural features of cerebral PNET arising in an adult male are presented. CASE: A cystic tumor, on computed tomography and magnetic resonance imaging, arose from the left frontal lobe in a 39-year-old man and contained histopathologic features of PNET. Specimens obtained from surgery revealed the presence of an undifferentiated type of PNET with moderate neuronal and glial differentiation and mild characteristic findings of peripheral PNET. The cytologic and histologic specimens showed evidence of a scattered pattern of blastic and undifferentiated tumor cells and a neural arrangement with Homer-Wright-like rosettes. Immunohistochemically, the tumor cells were glial fibrillary acidic protein, neuron-specific enolase, synaptophysin and CD-99 positive and epithelial membrane antigen, S-100 protein and vimentin negative. Ultrastructurally, neither microtubular structures nor intermediate filaments, except neurosecretory granules, were found in the tumor cells. CONCLUSION: Both immunohistochemical and ultrastructural studies on cytologic and histologic slides were important for the diagnosis of PNET because of establishing not only undifferentiated tumor cells but also neural and glial differentiation.

Adult↗
PubMedDate not supplied

Persistent infection with human polyomavirus revealed by urinary cytology in a patient with heart transplantation. A case report.

BACKGROUND: Management after heart transplantation must deal with the twin risks of rejection and infection. Early infection with viral infection, particularly cytomegalovirus (CMV), is becoming more prevalent two to three months after transplantation. To our knowledge, there has been no previous report of human polyomavirus (HPOV) infection after heart transplantation. CASE: A 20-year-old male with a history of Kawasaki disease and who had suffered from severe congestive heart failure after a coronary artery bypass graft, underwent heart transplantation. Urinary cytology demonstrated HPOV infection, the diagnosis of which was established by the immunoperoxidase technique, in situ hybridization and electron microscopy. CONCLUSION: The definitive diagnosis of HPOV infection after a heart transplant can be made on urinary cytology.

Adult↗
PubMedDate not supplied

Hematologic abnormalities and outcome of 16 cats with myelodysplastic syndromes.

We investigated the hematologic abnormalities and prognoses in 16 cats with myelodysplastic syndromes (MDS). Nonregenerative anemia, thrombocytopenia, and neutropenia were observed in 15, 13, and 4, respectively, of the 16 cats with MDS. Morphologic abnormalities characteristic of MDS included megaloblastoid rubricytes (9 cats), hyposegmentation of neutrophils (7 cats), nuclear abnormality of rubricytes (10 cats) and neutrophils (13 cats), and micromegakaryocytes (10 cats). Disease in these 16 cats was subclassified into refractory anemia (RA; 8 cats), RA with excess of blasts (RAEB; 5 cats), RAEB in transformation (RAEB in T; 1 cat), and chronic myelomonocytic leukemia (CMMoL; 2 cats), according to the human French-American-British (FAB) classification. In the cats in which the clinical outcome was known, 3 of 6 cats with high blast cell count MDS, including RAEB, RAEB in T, and CMMoL, developed acute myeloid leukemia, but only 1 of 8 cats with low blast cell count MDS (RA) developed acute myeloid leukemia. Based on the Dusseldorf scoring system for the prognosis of human MDS, the survival times of the cats showing high scores (> or =3 points) were significantly shorter than those of the cats with low scores (<3 points). The FAB classification and Dusseldorf scoring system were considered to be useful for predicting the prognosis of feline MDS. Furthermore, 15 of the 16 cats with MDS in this study were infected with feline leukemia virus, indicating its possible etiologic role in the pathogenesis of feline MDS.

Anemia↗
PubMedDate not supplied

HTLV-I-associated myelopathy (HAM) in Tokushima Prefecture--geographical and clinical studies in an area between endemic and non-endemic areas of HTLV-I infection.

The geographic distribution and clinical features of patients with HTLV-I-associated myelopathy (HAM) in Tokushima prefecture were investigated. Nine patients were found prior to December 1990. The minimal prevalence was estimated as 1.1 per 100,000 in the general population, and 1 per 1,309 in HTLV-I-seropositive persons. Seven patients were found in the southern district facing the Pacific Ocean, but only 1 patient each was found in the northern and western districts. The age at disease onset ranged from 15 to 53 yr (average 33 yr). The ratio of male to female patients was 1:8. Adult T cell leukemia was associated with HAM in 1 patient, and Hashimoto's disease in 2 patients. These cases have not been reported previously. The route of transmission of HTLV-I was concluded to be vertical in 4 patients and horizontal in 4 patients, but was uncertain in 1 patient. No evidence of transmission by blood transfusion was found in these patients.

Adult↗
PubMedDate not supplied

Factory outbreak of Escherichia coli O157:H7 infection in Japan.

To determine the cause of a July 1996 outbreak of Escherichia coli O157:H7 among factory workers in Kyoto, Japan, we conducted cohort and case-control studies. Eating radish sprout salad during lunch at the factory cafeteria had been linked to illness. The sprouts were traced to four growers in Japan; one had been associated with an outbreak of E. coli O157:H7 among 6,000 schoolchildren in Sakai earlier in July.

Case-Control Studies↗
PubMedDate not supplied

Heterozygous ras mutations are preserved in serially passaged human tumor xenografts and established cell lines.

We examined c-K-ras gene point mutations in human tumor xenografts and established cell lines as markers of genetic stability. Our previous study demonstrated the stability of c-K-ras gene mutations in human primary neoplasms and their tumor xenografts through serial passages in mice. In this study, we established 27 human cell lines derived from various human tumor xenografts in nude mice. Point mutation of the c-K-ras gene at codon 12 was found in 29.6% (8/27) of the cell lines, as well as in 29.6% (8/27) of the xenografts. The eight ras-mutated cell lines were derived from corresponding tumor xenografts carrying the ras mutation. Heterozygous ras gene mutation was confirmed in seven of the eight ras-mutated cell lines, as well as their corresponding xenografts. The incidence, type and heterozygosity of the c-K-ras gene mutation showed no discrepancies between the original xenografts and the established cell lines. From these findings, we concluded that point mutation of the c-K-ras gene was very stable in human tumor xenografts and established cell lines derived from the xenografts.

Animals↗
PubMedDate not supplied

Detection of HBs antigen with latex particles coated with human antibody prepared by affinity chromatography on concanavalin A-sepharose.

Human HBs antibody was isolated by affinity chromatography on HBs antigen absorbed to concanavalin A linked to Sepharose 4B. When a human anti-HBs immunoglobulin preparation obtained by Cohn's cold ethanol fractionation method was used as a starting material, the antibody was concentrated about 10 times in terms of the passive hemagglutination titer with a recovery rate higher than 50%. Latex particles coated with human anti-HBs antibody thus prepared were proved to be useful in detecting HBs antigen in human blood samples. In its sensitivity and in rapidity of its performance, the antibody-coated latex agglutination test seems to be superior to conventional immunodiffusion techniques.

Chromatography, Affinity↗
PubMedDate not supplied

High-resolution CT characteristics of poorly differentiated adenocarcinoma of the peripheral lung: comparison with well differentiated adenocarcinoma.

OBJECTIVE: The purpose of this study was to elucidate the characteristic high-resolution CT (HRCT) findings of poorly differentiated adenocarcinoma (PDA) in comparison with those of well differentiated adenocarcinoma (WDA). MATERIALS AND METHODS: We investigated the HRCT features of surgically resected PDAs (n=21) and WDAs (n=31). We analyzed the margin, CT attenuation, and internal architecture of the tumor and findings in the surrounding lung field, comparing them with the corresponding pathologic findings. RESULTS: Smoothness of the greater part (full-1/2 round) of the tumor and solid appearance were more prevalent in PDAs than WDAs (81% vs. 32%, 100% vs. 35%) [p<0.01]. Air-bronchogram was prevalent in WDAs (58%), but was never seen in PDAs [p<0.01]. Ground-glass opacity in PDAs pathologically corresponded to inflammation and edema in the alveolar space. CONCLUSIONS: Smoothness of the tumor margin and solid appearance without air-bronchogram were more commonly found in PDA than in WDA. HRCT may predict the histological differentiation of adenocarcinoma in selected cases in which differentiation is inconclusive by sputum cytology and transbronchial or CT-guided biopsy.

Adenocarcinoma↗
PubMedDate not supplied

Relapsed non-Hodgkin's lymphoma: detection and treatment.

PURPOSE: To evaluate the optimal management strategy during clinical remission and after relapse in patients with non-Hodgkin's lymphoma (NHL). METHODS: Sixty-six patients with relapse of NHL from a state of clinical remission between 1987 and 1997 were analyzed retrospectively. The pattern of relapses, diagnostic methods used for relapses, and clinical outcome of salvage treatment were analyzed with attention to time after the achievement of clinical remission. RESULTS: Thirty-three relapses (50%) occurred within 12 months, and the remainder occurred gradually from 12-48 months after the first remission. Diagnosis of relapse in 61 of the 66 patients (93%) was made at unscheduled evaluations prompted by symptoms, on physical examinations, or because of high LDH levels. The 1- and 5-year cause-specific survival rates after relapse were 56.7% and 39.4%, respectively. The 1- and 5-year relapse-free survival rates were 50.1% and 35.0%, respectively. The 5-year relapse-free survival rate in patients with late relapse (49.5%) was significantly better than in those with early relapse (21.2%) (p<0.01). CONCLUSION: Time to relapse may be a useful factor to determine optimal management strategy in NHL patients.

Adult↗