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Biomedical subjects

R Minami

Publications and source records attributed to R Minami.

At least 19 recordsLinked to original sources
PubMed2006

Observation and control of transverse energy-transport barrier due to the formation of an energetic-electron layer with sheared ExB flow.

Off-axis electron-cyclotron heating in an axisymmetric barrier mirror produces a cylindrical layer with energetic electrons, which flow through the central cell and into the end region. The layer, producing a localized bumped ambipolar potential Phi(C), forms a strong shear of radial electric fields E(r) and peaked vorticity with the direction reversal of E(r)xB sheared flow near the Phi(C) peak. Intermittent vortexlike turbulent structures near the layer are suppressed in the central cell by this actively produced transverse energy-transport barrier; this results in T(e) and T(i) rises surrounded by the layer.

Journal Article↗
PubMed2002

Variation in MT expression in early-stage depressed-type and polypoid-type colorectal tumours.

Metallothionein (MT) expression is observed in various carcinomas, but its role is not fully understood. To clarify the clinicopathological significance of MT, 87 colorectal adenomas and 128 early-stage carcinomas were immunohistochemically analysed for MT expression. The degree of MT immunostaining of a specimen was graded according to the proportion of MT-positive cells; negative (<5%) and positive (focally 5-50%, diffusely >50%). MT expression significantly decreased with tumour development. For carcinomas, MT-positivity was significantly associated with depth of invasion (T1 60% versus T2 33%; P<0.01), vascular involvement (positive 35% versus negative 61%; P<0.01) and morphology (polypoid 62% versus depressed 26%; P<0.01). Regarding MT-positive distribution, the diffuse-positive rate in MT-positive polypoid lesions was 28%, while MT-positive depressed lesions were all diffusely stained (P<0.01). In conclusion, our results suggested that decreasing MT expression is an early event in colorectal carcinogenesis and may reflect local invasion. Furthermore, MT-positive distribution may reflect genetic differences between the polypoid and depressed-type.

Adult↗
PubMed2001

Generalized scaling laws of the formation and effects of plasma-confining potentials for tandem-mirror operations in GAMMA 10.

The main operations from 1979 to 2000 in the GAMMA 10 tandem-mirror, characterized in terms of the high-potential mode having kV-order plasma-confining potentials and the hot-ion mode yielding fusion neutrons with 10-20 keV bulk-ion temperatures, are summarized and generalized as a result of scalings of the formation and the effects of the potentials. The wide validity of potential-formation physics from Cohen's theory and the validity of the generalized Pastukhov's theory for the effects of thermal-barrier potentials on electron confinement are verified and consolidated through electron-energy balance.

Journal Article↗
PubMed2001

Hepatocellular carcinoma with a sarcomatous appearance: report of a case.

A 59-year-old man was admitted with general fatigue, an epigastric mass, and remittent fever. Radiological examinations disclosed a huge solid-to-cystic mass in the right lobe of the liver, and the mass severely compressed the right diaphragm, the inferior vena cava, and the right atrium. In addition, the patient suffered from chronic hepatitis; however, the serum alpha-fetoprotein, carcinoembryonic antigen, and PIVKA II levels were all within the normal ranges. The serum C-reactive protein level was 7.71mg/dl. With a clinical diagnosis of a malignant hepatic tumor invading the right diaphragm, surgery was performed. The tumor originated from segments IV and VII of the liver, was well defined, and grew extrahepatically. The tumor was resected using an ultrasonic cavitational aspirator together with the infiltrated right diaphragm. The resected tumor measured 23 x 13 x 23cm in size and weighed 3,700 g. Histologically, the tumor was found to consist of hepatocellular carcinomatous component and sarcomatous component. In the sarcomatous component, spindle-shaped cells which were positive for the immunohistochemical localization of vimentin, alpha-smooth muscle actin, and keratin were identified. The postoperative course was uneventful. The value of the serum C-reactive protein returned to within the normal range, and the patient became afebrile. The patient received a postoperative combination chemotherapy (etoposide, epirubicin, and cisplatin), and remains well with no signs of recurrence 12 months after the operation.

Carcinoma, Hepatocellular↗
PubMed2001

Glut1 expression in T1 and T2 stage colorectal carcinomas: its relationship to clinicopathological features.

Glucose uptake is mediated by glucose transporter (Glut) proteins, which exhibit altered expression in a variety of malignant neoplasms. Glut1 expression is thought to be a potential marker for malignant transformation. The aim of the present study was to investigate the expression of Glut1 protein in colorectal adenomas, T1 and T2 stage carcinomas. Immunohistochemical detection of Glut1 protein was examined in 141 formalin-fixed and paraffin-embedded colorectal tumour specimens (57 adenomas, 84 carcinomas). The degree of Glut1 immunostaining of a specimen was graded according to the proportion of Glut1-positive cells in it; absent (positive cells are 0%), weakly positive (less than 10%), moderately positive (10-50%), and strongly positive (more than 50%). Glut1 expression was present in 18% of the adenomas with low-grade dysplasia, and in 63% of the adenomas with high-grade dysplasia. The positivity in such lesions was usually weak, but was moderate in 8% of the adenomas with high grade dysplasia. For the carcinomas, there were significant correlations between Glut1-positivity and depth of invasion (T1 45% versus T2 74%, P<0.01), histological differentiation (well 49% versus moderately to poorly 74%, P< 0.05) and morphological type (polypoid 42% versus depressed 73%, P< 0.05), if the cut-off value was set at 10% of cells. In conclusion, we clarified the relationship between Glut1 expression and clinicopathological features in T1 and T2 stage colorectal carcinomas, and our results suggested a high malignant potential of the depressed-type carcinoma.

Adenocarcinoma↗
PubMed2001

Subcutaneous malignant epithelioid schwannoma with cartilaginous differentiation.

BACKGROUND: Malignant epithelioid schwannoma is a rare tumor. The aim of this study is to describe a case of subcutaneous malignant epithelioid schwannoma with cartilaginous differentiation. METHODS: Histological, immunohistochemical, and ultrastructural examinations were performed on a tumor that arose on the back of a 37-year-old woman. RESULTS: Histologically, the tumor predominantly consisted of small, round or polygonal cells arranged in cords or nests. Immunohistochemical study revealed that the tumors cells were positive for vimentin, S-100 protein, glial fibrillary acidic protein and neuron specific enolase. The cells were negative for HMB-45, keratin, epithelial membrane antigen, and CAM5.2. Electron microscopic study showed closely associated cells with undifferentiated features. The cells were devoid of external laminae and cellular junctions. CONCLUSION: Malignant epithelioid schwannoma should be pathologically differentiated from other epithelioid tumors with cartilaginous elements.

Adult↗
PubMed2001

Pigmented neurofibroma: report of two cases and literature review.

Two cases of pigmented neurofibroma of the skin are reported. In case 1, the tumor was removed from the back of a 55-year-old man with no associated neurofibromatosis. In case 2, the tumor was removed from the abdominal wall of a 21-year-old woman with neurofibromatosis. Both tumors consisted of benign, short spindle cells and multiple foci of scattered melanin-laden cells. In case 1, the spindle cells were arranged in a storiform pattern, resembling features of dermatofibrosarcoma protuberans. Immunohistochemically, the spindle cells of both cases were demonstrated to be positive for S-100 protein and CD34. The melanin-laden cells stained positively for HMB-45. This report describes an additional two cases of pigmented neurofibroma that conform to the new diagnostic criteria for this disease.

Adult↗
PubMed2001

Lower abdominal phlegmon due to spontaneous rupture of an ileal neobladder.

A case is presented of spontaneous rupture of an ileal orthotopic neobladder due to a large residual urine volume. The present case is the 13th such case reported; however, this case is the first to show lower abdominal phlegmon and in which the perforation site was detected using computed tomography scanning. The indications for neobladder should be considered with great care. If spontaneous rupture is suspected, an early diagnosis of the perforation site and a measure of the extravasation volume using computed tomography are necessary. Appropriate treatment should include laparotomy.

Abdomen↗
PubMed2001

Angiosarcoma arising from skeletal haemangiomatosis in an atomic bomb survivor.

The authors report a unique case in which an angiosarcoma arose from skeletal haemangiomatosis in a 72 year old man. This patient had a history of atomic bomb irradiation more than 50 years ago. Radiographically, the patient had multiple sclerotic foci of benign haemangiomas in the pelvis, the sacrum, and the left femur. The patient developed a high grade angiosarcoma in the left pubic bone. It is thought that atomic bomb irradiation played an important role in the development of the malignant lesion.

Aged↗
PubMed2001

Aberrant BCR-ABL transcript with intronic insertion in a patient with philadelphia chromosome-positive chronic myeloid leukemia: implications for disease progression.

The BCR-ABL fusion gene is important for the leukemogenesis of chronic myeloid leukemia (CML). A relationship between types of BCR-ABL transcripts in CML and clinical features has been proposed. We present here a patient with CML who carried an aberrant BCR-ABL transcript with an intronic sequence insert. A 26-year-old woman was diagnosed as having Philadelphia chromosome (Ph) positive CML. Reverse transcription polymerase chain reaction detected an atypically large BCR-ABL mRNA transcript. Sequencing revealed a 589bp insertion consisting of a 5' portion of BCR intron b2 and a 3' portion of ABL intron 1b between BCR exon b2 and ABL exon a2. Although the typical b2a2 transcript was undetectable initially, it appeared after intensive chemotherapy. The aberrant transcript presumably arose as a result of a lack of splicing, and chemotherapy might modify the disease course by selecting the subpopulation of the CML clone expressing typical BCR-ABL mRNA dominantly.

Adult↗
PubMed2001

[Two cases of B cell lymphoma associated with hemophagocytic syndrome].

B cell lymphoma-associated hemophagocytic syndrome (B-LAHS) is clinically characterized by hepatosplenomegaly and bone marrow invasion without lymphadenopathy and skin lesions. Several cases of B-LAHS have been reported to demonstrate histopathologic findings of intravascular lymphomatosis (IVL), which in Western countries is characterized by a high rate of skin involvement and, rarely, bone marrow involvement and hemophagocytosis. Here we describe two interesting cases of B-LAHS. One patient was a 52-year-old woman whose bone marrow showed proliferation of large CD20-positive cells and hemophagocytosis at presentation. Combination chemotherapy was not effective, and the patient died of progressive disease. At autopsy, the lymphoma cells showed extravascular proliferation in many organs such as the bone marrow and liver, whereas in the adrenal glands, the lymphoma cells showed intravascular proliferation. The other patient was a 50-year-old man who had swellings of the bilateral kidneys and adrenal glands at presentation. Skin involvement by large lymphoma cells, a rare complication of B-LAHS, was observed. At autopsy, there was no evidence of IVL. Both of these patients showed high fever and cytopenia, and the disease took an aggressive clinical course, as in other reported cases of B-LAHS.

Female↗
PubMed2001

[Protein S deficiency in three patients with thrombosis].

Protein S (PS) deficiency, which is caused by various factors including congenital and acquired disorders, is a risk factor for thrombophilia. We described 3 patients with different backgrounds, who all exhibited PS deficiency. The first patient was a 47-year-old woman who suffered from frequent cerebral infarctions, deep-vein thrombosis (DVT) of her lower extremities, and pulmonary thromboembolism. Her son suffered from skin necrosis due to PS deficiency and both had the same mutant allele of the PS gene. The second patient was a 50-year-old woman who experienced a cold sensation in her fingers. Her relatives had a history of cerebrovascular disease. No mutation was detected in her PS gene. The third patient was a 27-year-old man with antiphospholipid antibody. He suffered from thrombocytopenia, skin necrosis, DVT of his lower extremities, and pulmonary thromboembolism. A mutation was identified in the steroid hormone-binding globulin-like (SHBG) domain of his PS gene. Neither his parents nor siblings had a history of thrombosis. The mutations found in the first and third patients were both missense mutations in the SHBG domain that have not been reported previously. The third patient had a mutation in the site that is involved in binding to C4b-binding protein, which modifies the immune response. These three cases provide key insights into the pathophysiology of PS deficiency.

Adult↗
PubMed2000

Flat-elevated and depressed, subtypes of flat early colorectal cancers, should be distinguished by their pathological features.

Flat-type colorectal tumors have are being detected with increasing frequency. It has become clear that these flat lesions contain two subtypes; flat-elevated and depressed lesions. However, their clinicopathological features and roles in colorectal carcinogenesis remain obscure. We classified colorectal adenomas and submucosal invasive cancers into three types: polypoid, flat-elevated, and depressed types. A clinicopathological study of 2505 colorectal tumors (2407 adenomas, 98 submucosal invasive cancers) was then performed. Furthermore, 64 tumors (25 adenomas with high-grade dysplasia, 39 submucosal invasive cancers) from which DNA was extracted were examined for K-ras gene mutation. The percentages of each configuration in the resected materials were 62.0%, 36.4%, and 1.6% of the polypoid, flat-elevated, and depressed types, respectively. The rate of submucosal invasive cancer in the depressed type was always high regardless of size. In the polypoid and flat-elevated types, lesions of larger size showed higher rates of invasion. Analysis of submucosal invasive cancers revealed no adenomatous components in any of the depressed-type lesions; in the polypoid and flat-elevated types the frequencies of cancer with adenomatous components were 83.6% and 77.8%, respectively. The flat-elevated type was more frequently located (77.8%) in the proximal colon than the other types (polypoid type 16.4%, depressed type 25.0%). The incidence of K-ras gene mutation was 47.2%, 18.2%, and 0% in the polypoid, flat-elevated, and depressed types, respectively. These findings suggest that the flat-elevated and depressed types are similar in that they are both morphologically flat and have infrequent incidences of K-ras gene mutation, but these two lesions differ in their pathological features. Especially, depressed type lesions have a tendency to invade the submucosal layer even when they are small. Therefore one should always be aware of this type of lesion during colonoscopic examination.

Adenoma↗