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N Tamahashi

Publications and source records attributed to N Tamahashi.

At least 19 recordsLinked to original sources
PubMed2001

Comprehensive allelotype study of ovarian tumors of low malignant potential: potential differences in pathways between tumors with and without genetic predisposition to invasive carcinoma.

Ovarian tumors of low malignant potential (LMP) are intermediate between adenomas and ovarian carcinomas (OC); however, the relevance of LMP to ovarian carcinogenesis is not clear. We performed a comparative analysis of allelotypes in 50 cases of LMP (42 mucinous and 8 serous) and 23 cases of OC (15 mucinous and 8 serous) to investigate any differences in genetic changes. Analysis of loss of heterozygosity (LOH) using 25 microsatellite markers reportedly associated with OC revealed that the total LOH frequency at each marker was significantly lower in LMP than in OC (p < 0.01). However, 9 (36%) loci showed higher LOH frequency in mucinous LMP than in mucinous OC. A genome-wide scan for LOH using 91 microsatellite markers and fine mapping revealed that LOH at D7S1805 (7q35) is characteristic of mucinous LMP (19.4% in mucinous LMP, 8.3% in mucinous OC). We further studied LOH in 3 cases of mucinous OC that were accompanied by mucinous LMP lesions. In 2 cases, LOH frequency was higher in the carcinoma portion than in the morphologically LMP portion. The other case showed microsatellite instability in the morphologically LMP portion and LOH in the carcinoma portion. Our results suggest the presence of an LMP-to-OC developmental sequence and the existence of a subset of LMP that does not develop into OC in the mucinous subtype of ovarian tumors.

Adenoma↗
PubMed1995

High accumulation of fluorine-18-fluorodeoxyglucose in turpentine-induced inflammatory tissue.

UNLABELLED: Fluorine-18-2-deoxy-2-fluoro-D-glucose ([18F]FDG) uptake and distribution in an experimentally induced inflammatory tissue were investigated. METHODS: Rats were subcutaneously inoculated with turpentine oil to induce inflammation and used for tissue distribution studies and autoradiography. RESULTS: Time course study of [18F]FDG tissue distribution showed that the uptake in inflammatory tissue increased gradually until 60 min and then decreased. A longitudinal study of [18F]FDG tissue distribution showed that the uptake increased progressively to a peak 4 days after inoculation and then decreased. On the fourth day postinoculation, a section of inflammatory tissue showed characteristic changes of chronic inflammation. Macro- and micro-autoradiography showed a high density of silver grains in the abscess wall consisting of an inflammatory cell layer and granulation tissue. Grain counting on micro-autoradiography of the abscess wall showed that the highest grain density was found in the marginal zone of young fibroblasts, endothelial cells of vessels and phagocytes of neutrophils and macrophages, followed by that in the neutrophil layer and granulation tissue. CONCLUSION: Our results indicate that [18F]FDG PET may be useful in detecting and monitoring chronic inflammatory processes.

Animals↗
PubMed1995

Methionine uptake by tumor tissue: a microautoradiographic comparison with FDG.

UNLABELLED: L-methyl-11C-methionine (11C-Met) and 2-deoxy-2-18F-fluoro-D-glucose (18F-FDG) are used for tumor diagnosis and treatment evaluation by PET. In order to examine the role of these tracers in cancer imaging, intratumoral properties of 14C-Met were studied and compared to those of 18F-FDG. METHODS: The distribution of 14C-Met in various cellular elements of two different mouse malignant tumor tissues, MH134 and FM3A, was analyzed serially using microautoradiography within a period of 120 min after injection of the tracer. RESULTS: Carbon-14-Met and 18F-FDG showed different distributions in tumor tissue. Carbon-14-Met uptake by the tumor was mostly by viable cancer cells. The uptake by macrophages and other cellular components was low. The uptake was higher in the highly proliferative tumor but did not reflect protein synthesis. The rapid and slow growing tumors demonstrated that 14C-Met uptake ratio was lower than that of 18F-FDG, reflecting de novo DNA synthesis ratio. CONCLUSION: Carbon-14-Met uptake represents the presence of viable cancer cells. Carbon-11-Met may be suitable for treatment evaluation of individual tumors but not growth rates of different tumors. Fluorine-18-FDG reflects tumor-host immune system reaction and is an excellent tool for pretreatment evaluation of tumors and determination of tumor proliferative activity.

Animals↗
PubMed1994

Active and passive mechanisms of [fluorine-18] fluorodeoxyglucose uptake by proliferating and prenecrotic cancer cells in vivo: a microautoradiographic study.

UNLABELLED: In this study, [18F]FDG uptake mechanisms were investigated in neoplastic cells during cell proliferation and cell death. METHODS: Detailed analysis was performed on mouse tumor models of different growth rates using [18F]FDG, [6-13H]thymidine [3H]Thd (a precursor of DNA synthesis) and [125I]bovine serum albumin ([125I]BSA) (a marker of diffusion) with autoradiographic and histopathologic techniques and electron microscopy. RESULTS: The three compounds, [18F]FDG, [3H]Thd and [125I]BSA, showed different heterogeneous patterns of distribution within tumor tissue sections in neoplastic and non-neoplastic cellular elements. The uptake of [18F]FDG by prenecrotic (or necrobiotic) tumor cells surrounding focal necrotic cell debris was 1.5 to 2.3 times higher than that of viable tumor cells. Prenecrotic cells did not retain trapped [18F]FDG; therefore, the uptake was considered to be nonmetabolic. Inconspicuous cell membrane, vesicular cytoplasmic organelles and condensed nuclear chromatin were remarkable findings in the prenecrotic cells. A comparison of viable tumor cells in tumors undergoing different growth rates showed that the ratio of [18F]FDG uptake was similar to that of [3H]Thd uptake in each S-phase cell. Fluorine-18-FDG showed a cell cycle dependency, with a higher uptake observed in cells in G0/G1 and G2 phases of the cell cycle compared with the S and M phases. CONCLUSION: A passive mechanism of [18F]FDG uptake may exist in the necrobiotic/prenecrotic or hypoxic/anoxic cells in tumors. However, the discordance of [18F]FDG and [3H]Thd uptake may be the result of the different cell cycle dependency of tracer uptake in the same tumor.

Animals↗
PubMed1994

Microautoradiographic study for the differentiation of intratumoral macrophages, granulation tissues and cancer cells by the dynamics of fluorine-18-fluorodeoxyglucose uptake.

UNLABELLED: A substantial amount of macrophage infiltration occurs in both human and animal tumors. We previously showed that 2-deoxy-2-[18F]fluoro-D-glucose ([18F]FDG) uptake was higher in tumor-associated macrophages and young granulation tissues than in tumor cells. Differentiation of intratumoral non-neoplastic cells from neoplastic cells is important not only for the reduction of false-positives in FDG-PET tumor studies but also for patient management. METHODS: A time-course study was performed using micro- and macro-autoradiography and tissue distribution in C3H/He mice bearing transplanted syngeneic FM3A mammary carcinoma and MH134 hepatoma was evaluated to analyze the intratumoral cellular dynamics of [18F]FDG and 2-deoxy-D-[3H]glucose in vivo. RESULTS: The volume-doubling time in vivo was 1.3 days for MH134 and 4.9 days for FM3A, and the survival time of the host was 32.1 and 40.3 days, respectively. The peak uptake of both tracers in the tumor was 60 min after intravenous injection. The uptake by MH134 was 1.7-2.1 times higher than that by FM3A. The intracellular concentration as determined by counting the silver grains on micro-autoradiographic sections showed that the uptake by macrophages and focal small necrotic areas in both tumors was faster than the blood clearance until 15 min after tracer injection. CONCLUSION: Thus, non-neoplastic cellular elements can be differentiated from viable neoplastic cells by means of the dynamic analysis of [18F]FDG uptake.

Animals↗
PubMed1993

Development of antigenic heterogeneity in the splenic meshwork of severe combined immunodeficient (SCID) mice after reconstitution with T and B lymphocytes.

Recently, we produced monoclonal antibodies reacting specifically with the reticular meshwork (RM) of lymphoid tissues, and demonstrated that, in the splenic white pulp of normal mouse, the antigenic heterogeneity of RM was associated with the segregation of the T and B lymphocytes. In the present study, we attempted to visualize further the interaction between splenic RM and T and B lymphocytes transferred into severe combined immunodeficient (SCID) mice. The splenic white pulp of naive SCID mice, containing a few T and B cells, showed little tendency for T-B segregation and antigenic diversity of RM. Transfer of spleen or bone marrow cells from normal mice resulted in complete recovery of lymphocyte populations, showing not only a clear segregation of T and B lymphocytes but also a remarkable antigenic diversity of RM. The same results were obtained following the transfer of spleen or bone marrow cells from the nude mouse. Next, we transferred purified T lymphocytes to one group of SCID mice and B cells to another. In mice given T cells, a few B cells were observed in the white pulp; T lymphocytes lodged not only in the inner periarterial lymphatic sheath (PALS) but also in the outer PALS and follicles. In the animals to which B cells were transferred, T cells were few and the homing of B cells occurred only into their proper compartments, such as the outer PALS, follicles and marginal zone, but not in the inner PALS. Thus, B cells can home into their proper compartments of the splenic white pulp independently of T lymphocytes.

Animals↗
PubMed1992

The microvasculature of the human bone marrow correlated with the distribution of hematopoietic cells. A computer-assisted three-dimensional reconstruction study.

Surgical specimens of ordinary bone marrow from eight patients were submitted to computer-assisted three-dimensional reconstruction from resin-embedded, semi-thin serial sections. This was undertaken with the aim of contributing to a better understanding of hematopoietic microenvironment by establishing the basic architecture of the bone marrow, particularly the microvasculature and its relation to the hematopoietic cell series. The basic vascular structure was found to consist of mutually intertwining sinuses and hematopoietic cords (or compartments), the latter with an arteriole running along the axis. This allowed to define the unitary structure of the bone marrow as a hematopoietic cord with a central arteriole and surrounded by sinuses. Here granulopoietic cells were distributed mostly along the wall of the central arteriole. Erythropoietic cells, located mainly around the sinus wall, proved to be forming a continuous network of cord instead of separate "islands" as usually assumed, justifying a designation of "erythroblastic cords". Megakaryocytes were positioned in close vicinity to the sinus wall. These findings appear not only to be helpful in analyzing factors involved in the in vivo hematopoiesis of man, but also to visualize the importance of structural studies of bone marrow.

Adult↗
PubMed1992

Intratumoral distribution of fluorine-18-fluorodeoxyglucose in vivo: high accumulation in macrophages and granulation tissues studied by microautoradiography.

While 2-deoxy-2-[18F]fluoro-D-glucose ([18F]FDG) is a useful tumor imaging agent, its intratumoral distribution has not been described well at the cellular level. In order to demonstrate cellular localization of [18F]FDG and 2-deoxy-D-[3H]glucose (3H-DG) uptake by the tumor in vivo, C3H/He mice transplanted subcutaneously with FM3A tumors were studied 1 hr after intravenous injection of [18F]FDG or 3H-DG using micro- and macro-autoradiography. Fluorine-18-FDG and 3H-DG showed the same distribution pattern in the tumor with both autoradiographic methods. The newly formed granulation tissue around the tumor and macrophages, which were massively infiltrating the marginal areas surrounding necrotic area of the tumor showed a higher uptake of [18F]FDG than the viable tumor cells. A maximum of 29% of the glucose utilization was derived from nontumor tissue in this tumor. The comparison of double-tracer autoradiographic distribution patterns of [18F]FDG and [6-3H]-thymidine showed the differences and the similarities between glucose utilization and the DNA synthesis. Whole proliferating tissue metabolizes [18F] FDG but not vice versa. High accumulation of [18F]FDG in the tumor is believed to represent high metabolic activity of the viable tumor cells. Our results showed that one should consider not only the tumor cells proper but also the non-neoplastic cellular elements, which appear in association with growth or necrosis of the tumor cells, for precise analysis of [18F]FDG uptake in tumor-bearing subjects, especially after anti-neoplastic treatment.

Animals↗
PubMed1992

[Autoradiographic demonstration of 18F-FDG distribution within mouse FM3A tumor tissue in vivo].

To demonstrate the distribution of 2-deoxy-2-18F-fluoro-D-glucose (FDG) within the tumor in vivo, C3H/He mice transplanted with FM3A tumors were studied one hour after intravenous injection of FDG using whole-body, macro- and micro-autoradiography. The whole-body autoradiograph showed that the tumor mass as well as the brain, heart, bone marrows, and the diaphragm and crus diaphragm were clearly visualized. The macro-autoradiograph showed the heterogeneous distribution of FDG in the tumor mass. Markedly dense areas surrounding the tumor and the necrotic area were observed. Micro-autoradiograph showed the high grain densities in the macrophages between the necrosis and viable tumor cells, and in the young granulation tissues demarcating between the tumor and surrounding intact host tissues. Our results showed that the FDG uptake in the tumors may reflect not only the uptake by the tumor cells but also that by the inflammatory reaction elements.

Animals↗
PubMed1991

Antigenic heterogeneity of the reticular meshwork in the white pulp of mouse spleen.

Monoclonal antibodies against cellular components of reticular meshworks were produced by immunizing rats with heterogeneous stromal-cell population of mouse spleen. Immunohistochemical screening selected two antibodies, WP-1 and RPSC-2. WP-1 proved to immunostain the meshwork of the B area densely, leaving the marginal zone unstained; it also reacted sparsely with the meshwork of the T-cell region. In contrast, RPSC-2 selectively immunostained the meshwork of the T region. Immuno-electron microscopy clearly visualized, for both antibodies, reaction products being deposited along the cytomembrane of the fibroblastic reticulum cells, along their abundant cytoplasmic processes that were densely intertwined with lymphocytes. Double immunostaining with RPSC-2 followed by WP-1 clearly divided the white pulp into the T and the B domains. The meshwork in the T-cell region proved to be immunostainable with both WP-1 and RPSC-2. Thus, the fibroblastic reticulum cells of the T- and the B-cell areas, while indistinguishable by routine microscopy, are at least partially heterogeneous.

Animals↗
PubMed1989

Fatal acute interstitial pneumonia induced by low-dose doxorubicin and vindesine.

A 53-year-old female smoker with small cell carcinoma of the lung with cerebral metastases was initially treated with whole brain radiation with favorable responses. She developed fulminant and fatal interstitial pneumonia following administration of 30 mg of doxorubicin and 6 mg of vindesine. Histopathology revealed that the interstitial pneumonia was compatible with a drug-induced pneumonia.

Acute Disease↗
PubMed1988

Isolated dog hearts prepared in cold tyrode solution and reperfused with arterial blood are functionally and ultrastructurally normal.

Isolated dog whole heart preparations run by means of cross-circulation with support dogs were prepared in two different ways. In one way the donors' hearts were quickly removed, and cannulation of their major vessels, insertion of a latex balloon into the left ventricle, etc. were all done in cold Tyrode solution in the condition of heart-anoxia within 30 min and then reperfused with arterial blood of support dogs (Group A). In the other, cannulation of the major vessels of the donors' hearts were done in the state of "beating heart" (Group B). In these two kinds of preparations we compared basal cardio-coronary measurements (coronary blood flow, left ventricular pressure (LVP), its first derivative (LV dP/dt) and myocardial oxygen consumption (MVO2) and ultrastructure of the myocardium at various periods of the experiments. There were no significant differences in these cardio-coronary measurements and ultrastructural findings. Furthermore, Group A preparations kept stable levels of cardio-coronary measurements for 5 hr or more and responded normally to isoproterenol. Therefore, isolated, blood-perfused dog whole hearts prepared in cold Tyrode solution and reperfused by means of the cross-circulation method would be useful for physiological, pharmacological and biochemical studies.

Animals↗
PubMed1987

Results of surgical treatment for thymoma based on 66 patients.

Sixty-six patients with thymoma have undergone surgical treatment since 1965 and have been assessed from the viewpoint of clinical manifestations and prognosis. Thirty-one patients with encapsulated thymoma were treated with total surgical resection alone, and they had no postoperative tumor recurrence. With the exception of one patient who died of respiratory insufficiency on the fourth day after the operation, 34 patients with invasive thymoma were evaluated on the basis of their postoperative prognosis. Fifteen patients with invasive thymoma died from 1 1/2 months to 10 years, 1 month postoperatively; 9 died of local or metastatic tumor and 6 died of other diseases. Associated autoimmune diseases, as well as the invasive tendency of the tumors, apparently affected the prognosis. Ten-year survival rates of the patients who underwent surgical treatment were as follows: 61.6% for the total group, 74.3% for those with encapsulated thymoma, and 49.4% for those with invasive thymoma. In the surgical treatment for invasive thymomas, one should aim to resect the tumor totally, even though adjacent tissues are resected simultaneously. Even for the patient with total resection of invasive tumor, postoperative radiation should be required. Finally, if residual tumor must be left during the operation, postoperative radiation as well as anticancer chemotherapy should be aggressively scheduled, because postoperative distant metastasis may appear in these patients with residual thymoma.

Adolescent↗
PubMed1985

The functional significance of human notochord in the development of vertebral column. An electron microscopic study.

Twenty-one human embryos or fetuses from four to twenty-one weeks in gestation age were submitted to light and electron microscopic observations of the notochord and its related structures. The notochord cells were found to have densely developed rER and Golgi areas, which were correlated with an activity to secrete into their surroundings specific ground substance probably containing proteoglycan. The highest differentiation of this cell as estimated by the peak secretory activity was reached at about ten weeks, while signs of degeneration emerged shortly thereafter and became increasingly apparent with the advancing gestation. The synthesis and secretion of matrices were likely to be taken over by the fibrocartilage cells surrounding the notochord by about 20 weeks when the notochord cells had undergone severe degenerative changes. Another characteristic feature of the notochord cells at their fully differentiated stage was abundance in intracytoplasmic glycogen that coexisted with striking paucity of mitochondria. This was interpreted as suggesting the metabolic dependence of these cells upon anaerobic glycolysis even at the peak of their secretory performance.

Cartilage↗
PubMed1981

Electron microscopic studies on cell-sized bilayer liposomes.

Cell-sized bilayer liposomes have been visualized directly in the electron microscope by a thin section method. Fixation in lanthanum nitrate plus potassium permanganate has made this visualization possible. Trilamellar images were seen in thin sections of the fixed liposomes; measurements made from microdensitometer tracings revealed a thickness (peak-to-peak distance) ranging from 25.3 to 55.3 A. The mean peak-to-peak distance of 35.6 +/- 8.2 A (+/- S.D.) was in good agreement with the value obtained by Robertson from typical myelin figures.

Liposomes↗