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Biomedical subjects

M Fukunaga

Publications and source records attributed to M Fukunaga.

At least 163 records · Page 9Linked to original sources
PubMed1997

Pleomorphic hyalinizing angiectatic tumor of soft parts.

A case of recently described pleomorphic hyalinizing angiectatic tumor (PHAT) of soft parts is reported. The subcutaneous solid tumor arising in the axilla of a 58-year-old man was histologically characterized by sheets of mitotically inactive oval and pleomorphic cells, intranuclear cytoplasmic inclusions, and clusters of ectatic vessels with perivascular hyalinization. Mono- and multinucleated giant cells were also present. A hemangiopericytoma-like pattern of vascularity, pseudovascular spaces, stromal collagen with degenerative changes, and immunoreactivity for CD34 were observed. Since these features were very similar to those of solitary fibrous tumors of various sites and newly categorized giant cell angiofibroma, it is considered that PHAT, solitary fibrous tumor, and giant cell angiofibroma may be in the same family of tumor. The tumor was diploid with a low S-phase fraction. The patient was well with no evidence of disease for 23 months.

Antigens, CD34↗
PubMed1997

Small cell carcinoma of the ovary: a case report of large cell variant.

An extremely rare case of large cell variant of ovarian small cell carcinoma is described. A 34-year-old woman (gravida 1, para 1) had a unilateral ovarian mass measuring 17cm in greatest diameter and a metastatic lesion in the omentum. Microscopically, the tumor showed a diffuse arrangement of large, closely packed epithelial cells with abundant eosinophilic cytoplasm and large nuclei with prominent nucleoli. The tumor cells also were arranged in follicle-like and trabecular structures and cords. Immunohistochemically, many tumor cells were diffusely positive for epithelial membrane antigen and some cells contained cytokeratin CAM5.2, vimentin, neurofilament, neuron-specific enolase, or alpha-1 antitrypsin. However, no specific lineage was detected. The tumor was aneuploid by flow cytometry. The patient received chemotherapy postoperatively. However, the patient showed metastases in the inguinal and retroperitoneal lymph nodes. The serum calcium level, which was not measured preoperatively, was mildly elevated postoperatively. The patient was well with no evidence of disease 17 months after diagnosis. This tumor must be distinguished from other primary or metastatic 'undifferentiated' neoplasms, especially ovarian small cell carcinoma of pulmonary type and granulosa cell tumor.

Adult↗
PubMed1997

Endometrial low-grade stromal sarcoma with ovarian sex cord-like differentiation: report of two cases with an immunohistochemical and flow cytometric study.

Two cases of endometrial low-grade stromal sarcoma with ovarian sex cord-like differentiation occurring in a 39-year-old woman and a 42-year-old woman are presented. Both tumors, which were intramyometrial and measured 7.5 cm and 7.0 cm in greatest diameter, respectively, showed a multinodular, ill-demarcated, and yellowish white cut-surface. Histologically, most parts of the tumors were composed of trabecular, cord-like, or plexiform arrangements that were reminiscent of the growth pattern seen in ovarian sex cord tumors. Features of conventional endometrial low-grade stromal sarcoma were only focally observed. The tumors showed infiltrative margins and lymphatic invasion. The tumor cells were positive for vimentin, desmin, alpha-smooth muscle actin, and muscle actin (HHF35). The tumors were also positive for both estrogen and progesterone receptors. Both tumors were DNA diploid as determined by flow cytometry. One patient had recurrences, including osteolytic lesions in the pelvic bones, but had no evidence of recurrence or metastasis 11 months after the last surgery. The other patient had no evidence of tumor in a limited follow-up. Familiarity with the neoplasm and other uterine mesenchymal tumors with ovarian sex cord-like differentiation by gynecologists and pathologists is essential in avoiding misdiagnosis because adjuvant hormonal therapy may be effective in treating low-grade stromal sarcomas.

Adult↗
PubMed1997

Columnar cell carcinoma of the thyroid.

A case of columnar cell carcinoma of the thyroid occurring in a 50-year-old female is described. Histologically, the 2 cm tumor showed a prominent papillary architecture with thin fibrous cores covered by columnar cells and marked nuclear stratification. It also showed microfollicular, glandular, and solid patterns. The nuclear features were different to those of conventional papillary carcinoma and similar to those of follicular tumors. The tumor was principally encapsulated with vascular and minimal capsular invasion. The tumor cells were positive for thyroglobulin. The tumor was DNA diploid with a low S phase traction as determined by flow cytometry. The patient had no lymph node or distant metastasis. The patient was well and without disease 9 months after surgery. The possibility that the neoplasm is one of poorly differentiated thyroid carcinomas rises.

Biomarkers, Tumor↗
PubMed1997

Hemorrhagic and nonhemorrhagic stroke: diagnosis with diffusion-weighted and T2-weighted echo-planar MR imaging.

PURPOSE: To determine if diffusion- and T2-weighted echo-planar magnetic resonance (MR) imaging can be used to detect acute hemorrhagic stroke and to differentiate hemorrhagic from nonhemorrhagic stroke. MATERIALS AND METHODS: A total of 118 examinations (diffusion- and T2-weighted MR imaging) in 19 patients with 27 nonhemorrhagic strokes and in six patients with seven hemorrhagic strokes were performed. The ratios of apparent diffusion coefficient and of signal intensity on T2-weighted MR images in lesions to those in contralateral control areas were calculated. RESULTS: Decreased ADC was shown in lesions of acute (0-3 days) hemorrhagic stroke, as well as in lesions of acute nonhemorrhagic stroke. Hypointense areas were seen on T2-weighted MR images in patients with acute hemorrhagic stroke, in contrast to normal to increased signal intensity in those with acute nonhemorrhagic stroke. Apparent diffusion coefficient tended to remain decreased in hemorrhagic stroke lesions even 100 days after onset, in contrast to the increased coefficient in nonhemorrhagic stroke lesions at the late chronic stage (31 days or older). CONCLUSION: Diffusion- and T2-weighted echo-planar MR imaging can be used to detect and distinguish between acute hemorrhagic and nonhemorrhagic stroke.

Acute Disease↗
PubMed1997

Evidence for the distinct nature of F2-isoprostane receptors from those of thromboxane A2.

In rat glomeruli and mesangial cells, the thromboxane A2 (TxA2) mimetic, U-46,619, but not 8-iso-prostaglandin F2alpha (8-iso-PGF2alpha), reduced glomerular inulin space and increased inositol 1,4,5-trisphosphate production, effects abolished by SQ-29,548. In competitive binding studies using 8-iso-[3H]PGF2alpha or [3H]SQ-29,548, mesangial cells displayed TxA2 binding sites but not ones for 8-iso-PGF2alpha. In contrast, rat aortic smooth muscle cells possessed specific binding sites for both TxA2 and 8-iso-PGF2alpha and displayed functional responses to both agonists, such as time- and dose-dependent activation of mitogen-activated protein kinases. In these cells, the mean dissociation constant value for the isoprostane receptor was 31.8 +/- 5.7 nM. When human TxA2 receptor cDNA was expressed in Xenopus oocytes injected with the Ca2+-specific photoprotein, aequorin, 8-iso-PGF2alpha gave much weaker responses than U-46,619. These studies provide the first radioligand binding characteristics of the F2-isoprostane receptor and demonstrate its specific and heterologous cellular localization. These studies support the distinct nature and biological significance of isoprostane receptors and provide a tool for their further molecular characterization.

15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5↗
PubMed1997

Effects of cholestatic agents on the structure and function of bile canaliculi in neonatal rat hepatocytes in primary culture.

The effects of cytochalasin B and colchicine on the structure and function of bile canaliculi were studied in neonatal rat hepatocytes in primary culture. Cellular contacts of neonatal hepatocytes were not as tight as those of adult hepatocytes. There was no remarkable difference in the ultrastructure of bile canaliculi between neonatal and adult hepatocytes. Neonatal hepatocytes treated with cytochalasin B were round in shape and aggregated in groups of several cells. Actin filaments stained by rhodamine-phalloidin were disrupted and condensed at the cell periphery or around dilated bile canaliculi. Markedly-dilated bile canaliculi with less microvilli were observed by transmission electron microscopy while the secretory function of horseradish peroxidase, which was used as a marker for uptake, transport and secretion into bile canaliculi, were maintained. The lumen of dilated bile canaliculi was found close to the undersurfaces of hepatocytes by scanning electron microscopy after turning over the cultured cells. By colchicine treatment, the filamentous structure of microtubules in neonatal hepatocytes disappeared. The ultrastructure of the bile canaliculi was not affected by the treatment, but transport and secretion of horseradish peroxidase into bile canaliculi were inhibited. The development of strict cellular polarity in neonatal hepatocytes may be suppressed in neonatal hepatocytes; however, cholestatic agents which rearrange the cytoskeleton caused the same morphological or functional changes of bile canaliculi as in adult hepatocytes.

Animals↗
PubMed1997

Extrapleural solitary fibrous tumor: a report of seven cases.

Solitary fibrous tumors (SFTs) are rare, spindle-cell neoplasms generally associated with the serosal surface, especially the pleura. Histopathologic, immunohistochemical, ultrastructural, and flow cytometric analyses were performed on seven SFTs of extrapleural sites (two retroperitoneal, two soft tissue, one each peritoneal, nasal cavity, and orbit). Five patients were women, and two were men, aged from 21 to 68 years (average, 39 yr). All of the lesions presented as well-circumscribed masses. The lesions ranged in size from 2 to 20 cm in greatest diameter. Histologically, these lesions were entirely comparable to the pleural SFTs and lacked the characteristic features of other recognized neoplasms that occur in these regions. One tumor contained pleomorphic and round-cell sarcomatous foci. Immunohistochemically, all of the tumors were strongly positive for vimentin and CD34. Six of the seven tumors showed varying numbers of spindle cells positive for alpha smooth muscle actin, HHF35, neuron-specific enolase, Leu 7, or glial fibrillary acidic protein. Ultrastructural examinations of three tumors showed that they were composed of primitive mesenchymal or fibroblast-like cells. Six tumors examined were diploid by flow cytometric examination. Clinical follow-up in six patients ranged from 1 to 7.5 years (average, 2.6 yr) and showed that five patients remained well with no evidence of disease after excision and that the patient with the sarcomatous elements died of recurrence 2.5 years after surgical treatment. These findings suggest that SFTs represent ubiquitous neoplasms of fibroblasts or primitive mesenchymal cells with aggressive potential.

Adult↗
PubMed1997

Myofibroblastoma of the breast with diverse differentiations.

BACKGROUND: The histogenesis of myofibroblastoma of the breast remains unknown. DESIGN: Two cases of myofibroblastoma of the female breast were analyzed using light microscopy and immunohistochemistry. RESULTS: The tumors were well circumscribed and predominantly composed of bland bipolar spindle cells and interspersed bands of hyalinized collagen. Additionally, one tumor contained a cartilaginous island, and the other contained a well-defined small nodule that consisted of fascicular arrangements of mitotically inactive atypical cells, simulating atypical leiomyoma. Both lesions contained a fatty element. Immunohistochemically, spindle tumor cells expressed desmin, alpha-smooth muscle actin, muscle actin, and CD34. The atypical cells were strongly and diffusely positive for all these markers. Both tumors were DNA diploid and had a moderate S-phase fraction. The patients have no evidence of disease 4 and 18 months after simple excision. CONCLUSIONS: Myofibroblastoma of the breast may be a benign mesenchymal neoplasm capable of diverse lines of differentiation.

Adult↗
PubMed1997

[Theory and clinical application of functional MRI: 3D-functional brain mapping].

Functional magnetic resonance imaging (fMRI) was performed using a clinical 1.5 T MR scanner. Normal volunteers and patients with several neurological disorders were studied with somatosensory stimulation using sponge at right hand and visual stimulation using checkerboard pattern. Both fMR images by gradient echo echo planar imaging and three dimensional gradient echo images were studied. Reconstructed 3 dimensional functional brain mapping was superimposed on 3D anatomical images. Apparent signal increase was observed at contra lateral sensorimotor cortex and secondary sensory cortex with sponge stimulation. In the case of left homonymous hemianopia due to cerebral infarction, increasing signal was only observed surrounding left calcarine fissure by using stimulation of all visual field. In conclusion, fMRI and 3-D functional brain mapping has extremely high potentiality to examine pathophysiology of various neurological disorders.

Brain↗
PubMed1997

[Functional brain mapping in motor task and somatosensory stimulation using echo planar MRI].

Functional brain mapping was performed with a 1.5T clinical MRI apparatus. Single shot gradient echo echo-planar imaging (EPI) sequence was employed. Normal volunteers were studied with the task of grasping hand or opposition of fingers at the frequency of 3 Hz, median nerve electro-stimulation, pure somatosensory stimulation by roller for acupuncture. Apparent signal increase was observed at contralateral sensorimotor cortex with motor task. Signal changes delayed about 5 seconds compared with the start and the cessation of the task, which may suggest that regional changes of CBF and blood oxygen level in capillary and/or in venule lag behind electrical excitation. It was hard to detect the activated area with median nerve electro-stimulation. On the other hand, roller stimulation provoked distinct activated areas at contralateral sensorimotor cortex. The activated areas caused by the roller stimulation and the motor task coincided entirely, which suggests the possibility of the intermixed localization of primary areas of motor and somatosensory. It was also clearly demonstrated that the activated area was broader with quick (3 Hz) and complicated motor task (finger opposition) than with slow (1Hz) and simple motor task (hand grasping).

Adult↗
PubMed1997

[Compartment analysis of 123I-iomazenil brain on early and delayed SPECT].

We investigated the characteristics of 123I-Iomazenil (IMZ) SPECT images in 12 adults (six males and six females, with a mean age of 56.1 years). The washout rate of 123I-IMZ from the brain was estimated from two SPECTs done 15 min and 3 hr after injection. Although the washout was relatively slow, the rates differed in each intracerebral region, suggesting that the distribution of 123I-IMZ was gradually changing. Furthermore, assuming 123I-IMZ kinetics in the brain for the three-compartment, two-parameter model, the transition rate constant (K1) from the blood to the brain and the binding potentials (BP) of benzodiazepine to the receptor were calculated. The BP and K1 values were compared with 123I-IMZ SPECT counts and CBF values by 123I-IMP. The BP values correlated more closely with the counts on the delayed SPECT than those on the early SPECT. It was confirmed that delayed SPECT images reflect better the distribution of the benzodiazepine receptor than early images do. On the other hand, the K1 values correlated highly with CBF obtained by 123I-IMP, and this finding suggested that super-early SPECT images might be remarkably influenced by the distribution of CBF.

Adult↗
PubMed1997

[Three-dimensional brain mapping using fMRI].

Functional mapping of the activated brain, the location and extent of the activated area were determined, during motor tasks and sensory stimulation using fMRI superimposed on 3 D anatomical MRI. Twelve volunteers were studied. The fMR images were acquired using a 2 D gradient echo echo planar imaging sequence. The 3D anatomical MR images of the whole brain were acquired using a conventional 3D gradient echo sequence. Motor tasks were sequential opposition of fingers, clenching a hand and elbow flexion. Somatosensory stimulation were administered by scrubbing the palm and sole with a washing sponge. Visual stimulation consisted of full visual field stimulation. Data were analyzed by the cross-correlation method. Transversal fMR images and anatomical images were reconstructed using both volume-, surface-rendering methods, and reconstructed for coronal and sagittal sections. Activated areas were expressed using the three primary colors. Motor tasks activated the contralateral primary motor area (M1), the primary somatosensory area (S1) and the supplementary motor area (SMA). Somatosensory tasks activated the contralateral S 1, M1 and secondary sensory area (S2). Activated areas during full visual field stimulation was observed in the bilateral occipital lobe, including both the primary cortex. Three-dimensional brain mapping allowed visualization of the anatomical location and extent of the activated brain during both motor task and sensory stimulation. Using this method we could obtain a functional map similar to the Penfield's schema.

Adult↗
PubMed1997

[Comparative study on the tumor accumulation of 99mTc-tetrofosmin and 99mTc-MIBI in rabbits bearing VX-2 cancer].

Each of myocardial blood flow imaging agents has a potential usefulness as an agent for tumor scintigraphy. The tumor accumulation and washout of 99mTc-tetrofosmin and 99mTc-MIBI were comparatively studied using rabbits bearing VX-2 cancer. From seventeen to twenty days after the implantation of VX-2 cancer into the femoral region of seven rabbits, tumor to soft tissue accumulation ratio (T/S ratio) of each agent was calculated in early images (5 min after injection) and in late images (50 min after injection). Compared with 99mTc-tetrofosmin, the T/S ratio of 99mTc-MIBI was higher and, moreover, the washout was delayed. These results suggest that there is a difference in tumor accumulation property between these two agents.

Animals↗
PubMed1996

Homology of variable major protein genes between Borrelia hermsii and Borrelia miyamotoi.

Antigenic variation has been studied in detail for the etiological agent of relapsing fever, Borrelia hermsii. The variable major proteins (vmps) are found at its cell surface, enabling it to avoid the host's immune response. We have cloned and sequenced the vmp-gene (vmp)-like sequences from the Borrelia miyamotoi strains HT31 and FR64b and the deduced amino acid sequences were compared with the published vmp proteins vmp3, vmp24, and vmp33 of B. hermsii. The sequences were aligned and revealed pairwise sequence identities ranging from 45 to 51%, and differences were scattered throughout the sequences. Southern hybridization using the cloned vmp-like sequence of strain HT31 as a probe suggested that the vmp homologues reside on the linear plasmids of B. miyamotoi. The probe hybridized weakly with B. hermsii linear plasmids and restriction digests. These results suggest that B. miyamotoi has sequences resembling the vmp genes in B. hermsii.

Amino Acid Sequence↗
PubMed1996

Choriocarcinoma in situ at a first trimester. Report of two cases indicating an origin of trophoblast of a stem villus.

Two cases of choriocarcinoma in situ arising in a first trimester placenta are reported in a 28-year-old gravida 2, para 1, Japanese woman and a 38-year-old gravida 2, para 0. Both had a dilation and curettage (D and C) for vaginal bleeding and the absence of intrauterine fetus. No macroscopic abnormalities were noted in either case. However, histologically, localized nodules of neoplastic trophoblastic proliferation measuring 5 mm in the first case, and 6 mm in the second appeared to arise directly from normal stem villi and project into the intervillous space. Both tumours were composed of biphasic cytotrophoblast and syncytiotrophoblast. Fetal elements were not observed in either case. Radiographic studies showed no metastatic lesions in either patient. Urinary human chorionic gonadotropin levels were within normal range in both patients. The first patient had a normal full-term spontaneous vaginal delivery 22 months after the D and C and was free from disease without therapy at 32 months. The second patient was free from disease without therapy with a limited follow-up. These tumours provide evidence for an origin of choriocarcinoma from trophoblast of a stem villus. This report illustrates the need to perform thorough microscopic examination of the products of conception especially in the absence of a fetus or fetal parts.

Adult↗