Biomedical subjects

M Ohsawa

Publications and source records attributed to M Ohsawa.

At least 109 records · Page 6Linked to original sources

PubMed1997

Topoisomerase II inhibitors fail to induce chromosome-type aberrations in etoposide-resistant cells: evidence for essential contribution of the cleavable complex formation to the induction of chromosome-type aberrations.

The induction of chromosome-type aberrations is mediated by stabilization of the DNA-topoisomerase II (topo-II) complex, the cleavable complex (CC), induced by topo-II inhibitors. In the present study, in order to confirm the critical contribution of topo-II in producing chromosome-type aberrations, the inducibility of chromosome-type aberrations by topo-II inhibitors was compared between human epidermoid cancer KB cells and their mutant cells (KB/ VP-2 cells) which were resistant to etoposide (VP-16) and which have reduced levels of topo-II and its gene expression. KB/VP-2 cells were resistant to the cytotoxicity of topo-II inhibitors and most resistant to etoposide. In KB cells treated with etoposide which had accumulated CC, chromosome-type aberrations but not chromatid-type aberrations were efficiently induced, as has already been reported in Chinese hamster fibroblasts. In contrast, in KB/VP-2 cells with no accumulation of CC, etoposide induced mainly chromatid-type aberrations, with a few chromosome-type aberrations. Unlike etoposide, however, adriamycin, which was known to accumulate CC in Chinese hamster fibroblastic cells, neither induced chromosome-type aberrations nor accumulated CC in either KB or KB/VP-2 cells. No difference in cell incorporation of [3H]etoposide between the two cell lines was observed. These findings indicate that CC formation contributes to the induction of chromosome-type aberrations, although the reason why adriamycin could not accumulate CC in KB cells is not clear. This may suggest a mechanism for resistance to topo-II inhibitors in cancer chemotherapy.

Antineoplastic Agents, Phytogenic↗

PubMed1997

Anisotropic expansion in gypsum-bonded cristobalite investment mold.

Expansion of a gypsum-bonded investment mold was investigated using a fused quartz tube pattern. Two hours after mixing, a fusible alloy was cast into the space around the pattern induced by setting expansion. The other molds were heated up to 700 degrees C, then a dental silver alloy was cast into the space around the pattern induced by total expansion of the mold. Thickness of the castings was measured at every thirty degrees on seven cross-sections. The setting expansion was almost uniform, but the total expansion was not. Especially, a large amount of total expansion was produced toward the open ends of the casting ring and toward a seam of the asbestos liner. The thermal expansion of the mold was anisotropic because the investment was a mixture of calcium sulfate and silica, and was affected considerably by its environment.

Anisotropy↗

PubMed1997

Non-Hodgkin's lymphoma of Waldeyer's ring as a manifestation of lymphoproliferative diseases associated with human T-cell leukemia virus type 1 in southwestern Japan.

Adult T-cell leukemia/lymphoma (ATL) usually presents with node- and/or cutaneous-based diseases, with a leukemic picture. It is not clear whether ATL initially manifests with lesions in Waldeyer's ring (WR) in an ATL-endemic area. In the present study, we examined distributions of immunophenotypes and the presence of human T-cell leukemia virus type 1 (HTLV-1) and Epstein-Barr virus (EBV) genomes in 62 cases of non-Hodgkin's lymphoma (NHL) of WR (NHL-WR) from two areas of Japan: Osaka, an ATL-nonendemic area (25 cases), and Okinawa, an ATL-endemic area (37 cases). In both areas, age ranged from 10 to 94 years (median, 64 yr), with a male-to-female ratio of 1.81:1. Twelve patients were in Stage I, 34 in Stage II, and 6 in Stage III; stage was unknown in 10. The 25 Osaka cases were B-cell type (16 diffuse immunoblastic type (DIB), 8 diffuse large cell predominantly noncleaved cell (DLNC), 1 cleaved cell (DLC)). Of the 37 Okinawa cases, 20 were B-cell type (3 DIB, 10 DLNC, 2 DLC, 5 other). The remaining 17 cases showed T-cell phenotype (4 DIB, 3 DLC, 3 diffuse large cell not otherwise specified, 7 other). There was a significant difference in the distribution of immunophenotypes between these two areas (P < .001). Combined studies of polymerase chain reaction (PCR) and in situ hybridization revealed the presence of EBV genome in 1 (4%) of 24 Osaka cases, 2 (13%) of 16 B-cell NHLs from Okinawa, and 3 (23%) of 13 T-cell NHLs from Okinawa. HTLV-1 proviral genome was found in 11 (85%) of 13 T-cell lymphomas from Okinawa but could not be detected in B-cell lymphomas from Osaka and Okinawa. Combined clinical, histologic, serologic, and PCR findings suggest that NHL-WR in an ATL-endemic area could be an initial manifestation of ATL.

Adolescent↗

PubMed1997

Effects of streptozotocin-induced diabetes on place conditioning action of cocaine in mice.

The effect of diabetes on the cocaine-induced place conditioning in mice was examined. In non-diabetic mice, cocaine, at dose ranges from 1 to 30 mg/kg, s.c. caused a dose-related preference for the drug-associated place, and significant place conditioning was observed at 10 and 30 mg/kg. In diabetic mice, cocaine at a dose of 10 mg/kg, s.c. did not produce a significant place preference, but a significant place conditioning was observed at 30 mg/kg. These results suggest that the reinforcing property of cocaine in diabetic mice was less than that in non-diabetic mice.

Animals↗

PubMed1996

Effects of diabetes on methamphetamine-induced place preference in mice.

The effects of diabetes on methamphetamine-induced place preference in mice were examined. Methamphetamine caused a dose-dependent place preference in both diabetic and non-diabetic mice. Methamphetamine preferentially induced place preference in diabetic mice as compared to those in non-diabetic mice. Indeed, methamphetamine-induced place preference at a dose of 0.3 mg/kg in diabetic mice was similar to that at 3 mg/kg in non-diabetic mice. Furthermore, methamphetamine-induced place preference in both diabetic and non-diabetic mice was significantly antagonized by pretreatment with quinpirole, a dopamine D2/D3 receptor agonist. Methamphetamine-induced place preference was also antagonized by pretreatment with 7-hydroxy-N,N-di-n-propyl-2-aminotetralin (7-OH-DPAT), a selective dopamine D3 receptor agonist. On the other hand, 7-OH-DPAT produced significant place aversion in non-diabetic mice. 7-OH-DPAT produced neither place preference nor place aversion in diabetic mice. These results suggest that methamphetamine-induced place preference may be modulated by dopamine D3 receptors. Furthermore, increased dopamine neurotransmission associated with the down-regulation of presynaptic dopamine D3 receptor-mediated functions may account for the enhancement of methamphetamine's reinforcing effect in diabetic mice.

Animals↗

PubMed1996

Expression of Epstein-Barr virus latent infection genes and oncogenes in lymphoma cell lines derived from pyothorax-associated lymphoma.

Malignant lymphomas frequently develop in the pleural cavity of patients with long-standing pyothorax. The term pyothorax-associated lymphoma (PAL) has been proposed for this type of tumor. Most PALs are diffuse lymphomas of the B-cell type and contain Epstein-Barr virus (EBV) DNA. We have established 2 lymphoma cell lines from biopsy specimens of PAL cases, OPL-1 and OPL-2, and examined their growth characteristics and the expression of EBV latent infection genes and oncogenes. OPL-2 exhibited a more rapid growth and higher saturation density than OPL-1, and only OPL-2 exhibited colony-forming activity in soft agar. OPL-1 and -2 were positive for B-cell differentiation markers and showed clonal surface immunoglobulins. Both line contained a single predominant form of episomal EBV DNA, indicating clonal cellular proliferation of an EBV-infected progenitor cell. OPL-1 and -2 contained type B and A EBV genome, respectively. Expression of EBV nuclear antigen (EBNA)2 mRNA and protein was detected by Northern and Western blot analysis in OPL-1, but not in OPL-2. On the other hand, the expression of latent membrane protein (LMP)1 mRNA in both OPL-1 and -2 was extremely weak and detectable only by reverse transcription-polymerase chain reaction. Protein expression of LMP1 was not observed by Western blot analysis or immunocytochemistry. Both lines expressed c-myc mRNA. Only OPL-1 expressed mRNA of c-fgr, an oncogene whose expression is upregulated by EBNA2. Both OPLs expressed bcl-2 mRNA without detectable expression of LMP1 protein.

Aged↗

PubMed1996

Epstein-Barr virus in Hodgkin's disease patients in Japan.

BACKGROUND: The association of Epstein-Barr virus (EBV) and Hodgkin's disease (HD) has been suggested by serologic, epidemiologic, and molecular biologic studies. The high level of EBV association with HD in the developing countries was discussed in relation to the high HD incidence in these areas. Japanese HD shows a distinct peak incidence in older adults. In contrast, Western HD shows a bimodal pattern, the first peak in young adulthood and a second peak in older patients. In the present study, the EBV association with HD in Japan was investigated, and the results were compared with those reported from industrialized and developing countries. METHODS: Fifty-seven patients with HD were studied for the presence or absence of the EBV genome by the polymerase chain reaction and in situ hybridization methods. Seven cases were excluded from the analysis for EBV because of poor preservation of nucleotides in the specimens. RESULTS: EBV genomes were detected in the Reed-Sternberg (R-S) cells of 32 of the 50 patients examined (64%). The EBV association was independently affected by histologic subtype (84% in mixed cellularity and 44% in others), sex (76% in males and 31% in females), and age (76% in patients aged 40 years and older and 38% in patients younger than 40 years of age; P < 0.01). High EBV association is found at the peak in older adults predominantly with mixed cellularity type. Previous studies revealed that the high EBV was associated with the older peak of the bimodal peaks in Western HD, and a unimodal peak in childhood in developing countries. The EBV subtype was predominantly type A, which is identical to the immunocompetent type of HD reported previously. CONCLUSIONS: The results of the current study, together with those reported previously, showed that the presence of the Epstein-Barr virus correlated with mixed cellularity type, age older than 40 years, and male sex.

Adolescent↗

PubMed1996

Prognostic factors in angiosarcoma: a multivariate analysis of 55 cases.

Data for prognostic factors in angiosarcoma (AS) are limited, prompting a large-scale study of AS with multivariate analysis. To analyze prognostic factors in angiosarcoma (AS), clinical and histologic findings in 55 patients collected from hospitals in Japan were reviewed. Prognostic factors were evaluated by univariate and multivariate Cox's proportional hazards models. The study involved 32 males and 23 females, ages 18-93 (median, 69) years. The primary sites of tumors included head and neck (32 cases), trunk (10), extremities (3), spleen (3), breast (3), and other (4). The overall 2-year survival rate was 21%. Univariate analysis of clinical factors including age, sex, size and depth of tumor, tumor-related symptoms, interval between onset of symptoms and admission, surgical procedures, adjuvant chemotherapy, and adjuvant radiotherapy showed that age, tumor size, and mode of treatment were significant for survival. Histologic factors analyzed were mitotic counts, cellularity, cellular pleomorphism, extent of necrosis, vascular differentiation, and nonspecific diagnosis. Only mitotic counts were significant for prognosis. Multivariate analysis on these four factors revealed that tumor size, mode of treatment, and mitotic counts were independent prognostic factors.

Adolescent↗

PubMed1996

Occurrence of monocytoid B lymphocytes in lymph nodes of patients treated by chemotherapy.

Occurrence of monocytoi B lymphocytes (MBL) in the lymph nodes of patients receiving preoperative chemotherapy for cancer was examined and compared to lymph nodes in controls who had not received chemotherapy. Number of patients receiving and not receiving preoperative chemotherapy were 3 and 10 cases in ovarian cancer, 7 and 11 in testicular cancer, and 22 and 8 in lung cancer, respectively. Chemotherapeutic agents for ovarian, testicular, and lung cancer consisted of cisplatin, Adriamycin, and cyclophosphamide; cisplatin, vinblastine, and bleomycin; and cisplatin, vindesin, and mitomycin, respectively. MBL were defined morphologically as having abundant pale cytoplasm with distinct cell borders and small nucleus. Immunohistochemistry revealed a B-cell nature of these cells, i.e., CD20+ and/or MB-1+ together with negative reactivity for antibodies for T lymphocytes (CD43, CD45RO, OPD4) and macrophages (KP-1, PGM-1). Monocytoid cells in two cases showed a positive reactivity for CD43 together with CD20. The occurrence rate of MBL in patients with ovarian, lung, and testicular cancer receiving and not receiving chemotherapy was 67% (2/3) and 10% (1/10), 59% (13/22) and 75% (6/8), and 43% (3/7) and 9% (1/11), respectively. The occurrence rate in the total patients receiving chemotherapy (56%) was significantly higher than for those not receiving chemotherapy (28%) (P < 0.05). These findings suggest that chemotherapy-induced depressed immune function is causative for the occurrence of MBL in the lymph nodes. MBL might be found more frequently in nodes from patients who have received chemotherapy in certain settings.

Adult↗

PubMed1996

Possible involvement of mu 2-opioid receptor-mediated mechanisms in morphine-induced enhancement of the pentobarbital-induced loss of the righting reflex in the mouse.

The effects of pretreatment with selective mu-, delta- and kappa-opioid receptor antagonists on the enhancement of the pentobarbital-induced loss of the righting reflex by morphine were examined in mice. Mice injected with pentobarbital (50 mg/kg, i.p.) showed an increased duration for the loss of the righting reflex after administration of morphine. This enhancement of the pentobarbital-induced loss of the righting reflex produced by morphine (10 mg/kg, s.c.) was significantly antagonized by pretreatment with beta-funaltrexamine, a selective mu-opioid receptor antagonist, but not by pretreatment with naloxonazine, a selective mu 1-opioid receptor antagonist. Furthermore, neither naltrindole, a selective delta-opioid receptor antagonist, nor nor-binaltorphimine, a selective kappa-opioid receptor antagonist, had a significant effect on the enhancement of the pentobarbital-induced loss of the righting reflex by morphine. These results suggest that mu 2-, rather than mu 1-, delta- and kappa-, opioid receptor-mediated mechanisms are involved in the morphine-induced enhancement of the pentobarbital-induced loss of the righting reflex.

Animals↗

PubMed1996

Immunotoxic effect of low dose cisplatin in mice.

The immunosuppressive effects of cisplatin at relatively low doses were investigated in CD-1 mice. Mice were injected intraperitoneally with 8, 40 and 200 micrograms/kg cisplatin for 10 days. A decrease in body and thymus weights was observed at 200 micrograms/kg. Though there were no dose-related effects on the IgM antibody response to sheep erythrocytes, a statistically significant reduction of the contact hypersensitivity response (CHR) was seen at 200 micrograms/kg. In vivo and in vitro effects of cisplatin on T- and B-lymphocyte function were assessed by proliferative response to concanavalin A and lipopolysaccharide, respectively. Cisplatin inhibited splenic T-lymphocyte function more than splenic B-lymphocyte function. These data indicate that a relatively low dose of cisplatin induce immunosuppressive effects in mice with a greater effect on T-lymphocytes than the B-lymphocytes.

Animals↗

PubMed1996

Malignant lymphoma of the adrenal gland: its possible correlation with the Epstein-Barr virus.

Initial manifestation of malignant lymphoma in the adrenal gland is a rare event, and clinical and pathologic features are not fully understood. We conducted a nationwide study in Japan, and 20 patients with malignant lymphoma that showed initial and main manifestation in the adrenal gland were identified. Clinical and pathologic findings were summarized. In addition, the presence of the Epstein-Barr virus (EBV) genome in the tumor cells was examined by using polymerase chain reaction (PCR) and in situ hybridization (ISH), together with the immunohistochemical evaluation of the expression of latent membrane protein-1 (LMP-1). There were 13 men and seven women; their ages at admission ranged from 40 to 87 years (median, 65 yr). Fever, anemia, and elevation of lactic dehydrogenase levels were the common presenting findings. One patient had acquired immunodeficiency syndrome. Adrenal tumors were bilateral in 15 patients and unilateral (all in the left site) in five. Prognosis was very poor; all but two patients died within 1 year after admission. Histologically diffuse large cell type was the commonest type (14 specimens). Immunohistologically, 16 specimens were B-cell type, and one was T-cell type. Another three specimens showing no positive reaction for any antibodies were also judged as B-cell type on purely morphologic grounds. Prominent intravascular proliferation of tumor cells was found in five patients. PCR for EBV genomes gave positive results in five patients; the virus was subtyped as A in three patients and as B in two. The ISH provided positive signals in nine samples, including all five specimens positive for PCR. Four of the nine cases with detectable EBV by PCR and/or ISH expressed LMP-1. The present study shows that adrenal lymphoma is EBV associated and has a B-cell phenotype.

Adrenal Gland Neoplasms↗

PubMed1996

[Sinus venosus atrial septal defect: report of two cases with successful repair by the Vargas' procedure].

Two cases of sinus venosus atrial septal defect with partial anomalous of right upper pulmonary venous drainage into superior vena cava treated by the Vargas' procedure were reported. These patients were 5 and 6 years old. Post operative courses were uneventful, and results of postoperative hemodynamic and clinical evaluation were encouraging. The Vargas' procedure is useful method for a reconstraction of the anomaly in childhood because of use of the autologus tissues. Though long-term fate of this procedure is still uncertain. Then, we consider that a long-term follow up is necessary.

Cardiac Surgical Procedures↗

PubMed1996

[Large granular lymphocyte leukemia].

Large granular lymphocyte leukemia (LGLL) is defined as clonal proliferation of LGLs in peripheral blood. The following studies were conducted to address some issues in chronic LGLL. (1) Chronic LGLL is characterized by the indolent course, and the diagnosis of leukemia is difficult in such patients as those without distinct organomegaly and/or any evidence of monoclonality. We performed immunohistological studies in a patient with persistent NK lymphocytosis. No organomegaly had been seen in the patient during a three-year-observation, who died from cerebrovascular accident. The autopsy findings revealed multi-organ infiltration including spleen, liver, bone marrow, lymph nodes and lung. These findings suggest that the cells of chronic LGLL have infiltrative capacity characteristic of malignant cells. (2) Lymphocytosis in chronic LGLL is usually stable for a long period. We found that both T- and NK-LGLL cells strongly expressed CD95, an apoptosis related protein. Anit-CD95 did not induce apoptosis, but suppressed proliferation induced by IL-2 or anti-CD3. These results suggest that CD95-CD95 ligand system is involved in the slow cell growth characteristic of chronic LGLL. (3) CD4+CD8+ double positive (DP) cases are rarely seen in LGLL, and the physiologic counterpart of the leukemic cells has not been determined yet. We found that the DP-LGLL had alpha alpha type in the CD8 subunit and did not express RAG-1, these findings being characteristic of peripheral T cells. We also found that they expressed IL-4 mRNA and secreted IL-4 on activation. These results strongly suggest that DP-T-LGLL represents an expansion of a rare subset of peripheral DP-T cells, possibly derived from IL-4 activated CD4 single positive T cells.

Aged↗

PubMed1996

[LGL lymphoma].

We reported in this article two patients with large granular lymphocytic lymphoma (abbreviated as LGL lymphoma). One was the patient with LGL leukemia/lymphoma (patient 1) and other was the patient with NK-LGL lymphoma (patient 2). Because the gene of TCR delta was rearranged in the patient 1, the clonality of the LGL leukemia/lymphoma was confirmed. However, it is not determined yet whether the lineage of tumor cells is T cells or NK cells. The cytochemical features of the lymphoma cells of the patient 2 were studied. It was found that NK cell-derived lymphoma cells of the patient were positively stained with these two monoclonal antibodies that are reactive with T cell; one is anti-CD45RO (UCHL-1) and other is anti-CD3. Judging from the result, malignant NK-LGL cells in some patients are cytoplasmic CD3+ and UCHl-1+. It is emphasized that May-Grünwald-Giemsa stain of biopsied specimen of the lymphoma is required for making the diagnosis of LGL lymphoma.

Adult↗

PubMed1995

Use of immunohistochemical procedures in diagnosing angiosarcoma. Evaluation of 98 cases.

BACKGROUND: Differential diagnosis of angiosarcoma, predominantly showing a non- or poorly vasoformative proliferation from other types of sarcomas, poorly differentiated carcinomas, and amelanotic melanoma, is often problematic. METHODS: The use of antibodies directed against Factor VIII-related antigen (FVIIIRA), Ulex europaeus lectin type 1 (UEA-1), CD31, and vascular endothelial growth factor (VEGF) in the diagnosis of angiosarcoma was examined in 98 cases of autopsy-proven angiosarcoma diagnosed during 1974-1990 in a survey of 178 Japanese hospitals. Reactivity of angiosarcoma cells for epithelial membrane antigen, cytokeratin, and melanoma cell antigen (HMB45) also was examined. RESULTS: Histologic specimens were formed exclusively by vasoformative areas in 32 cases and combined vasoformative and varying extents of non- or poorly vasoformative areas in another 66 cases. In vasoformative areas, the proliferating cells showed a diffuse positive reaction in the cytoplasm and/or cell surface for anti-FVII-IRA in 82 (84%) of 98 cases, for anti-CD31 in 78 (80%), and for UEA-1 in 69 (70%). In non- or poorly vasoformative areas, the positivity rate for FVIIIRA, CD31, and UEA-1 was 29%, 62%, and 46%, respectively. A positive reaction was found for either one of three endothelial markers in the non- or poorly vasoformative areas of 57 cases (86%). Epithelial membrane antigen and anticytokeratin antibody were positive in 4 and 11 cases, respectively, in the vasoformative areas and in 3 and 14 cases, respectively, in non- or poorly vasoformative areas with a simultaneous positive reaction for either one of three endothelial cell markers. None of the proliferating cells showed a positive reactivity for HMB45. The positivity rates of the angiosarcoma cells for each marker were different according to the primary tumor sites. The angiosarcoma cells in non- or poorly vasoformative areas showed the lowest positivity rate for anti-FVIIIRA in the heart (9%) and for anti-CD31 in the extremities (17%) and the highest positivity rate for anticytokeratin in the trunk (60%). Ulex europaeus lectin type 1 had almost the same reactivity rate (30-56%) in every organ. Angiosarcoma cells in 13 (36%) of 36 biopsy specimens and 8 (14%) of 56 autopsy specimens were positive for the anti-VEGF antibody. CONCLUSION: These findings suggest that the combined use of endothelial cell markers including FVIIIRA, UEA-1, and CD31 is useful in the diagnosis of angiosarcoma, especially in cases exclusively with a non- or poorly vasoformative pattern.

Adolescent↗

PubMed1995

Antinociceptive effects of the selective non-peptidic delta-opioid receptor agonist TAN-67 in diabetic mice.

The antinociceptive potencies of 2-methyl-4 alpha alpha-(3-hydroxyphenyl)-1,2,3,4,4a,5,12,12 alpha alpha-octahydro-quinolino[2,3,3-g]isoquinoline (TAN-67), a non-peptidic delta-opioid receptor agonist, were examined using the acetic acid abdominal constriction test and the tail-flick test in diabetic mice. TAN-67, at doses of 3-100 mg/kg, s.c. [corrected], produced a marked and dose-dependent inhibition of the number of acetic acid-induced abdominal constrictions in both non-diabetic and diabetic mice. The antinociceptive effect of TAN-67 in the acetic acid abdominal constriction test in diabetic mice was greater than that in non-diabetic mice. Indeed, the ED50 (95% confidence limits) value of TAN-67 for the inhibition of acetic acid-induced abdominal constrictions in diabetic mice (6.0 (3.5-10.5) mg/kg) was significantly lower than that in non-diabetic mice (31.4 (14.2-69.4) mg/kg). The antinociceptive effect of TAN-67 was not antagonized by pretreatment with either beta-funaltrexamine, a selective mu-opioid receptor antagonist, or nor-binaltorphimine, a selective kappa-opioid receptor antagonist. When 7-benzylidenenaltrexone (0.3 mg/kg, s.c.), a selective delta 1-opioid receptor antagonist, was administered 10 min before treatment with TAN-67, the antinociceptive effect of TAN-67 was significantly antagonized. However, naltriben, a selective delta 2-opioid receptor antagonist, had no significant effect on the antinociceptive effect of TAN-67. Furthermore, in the tail-flick test, TAN-67 at doses of 3-30 mg/kg, s.c. [corrected], also produced a marked and dose-dependent antinociceptive effect in diabetic mice, but not in non-diabetic mice. In conclusion, TAN-67 produced an antinociceptive effect through the activation of delta 1-opioid receptors. Furthermore, the results of this study support our hypothesis that mice with diabetes are selectively hyperresponsive to delta 1-opioid receptor-mediated antinociception.

Analgesics↗

PubMed1995

Angiosarcoma in Japan. A review of 99 cases.

BACKGROUND: Angiosarcoma is rare, and information about its clinical features are limited. Therefore, a large scale study of angiosarcoma was performed in Japan. METHODS: Through a nationwide Japanese study, 99 cases of angiosarcoma were collected and their clinicopathologic findings were summarized relative to predisposing risk factors. RESULTS: The patient age at diagnosis was 3-92 years, (mean, 62 years), with a two to one male to female ratio. The head and face were the most common primary site (29 cases); other sites were liver (17); trunk (13): pleural cavity (6), chest wall (2), abdominal wall (2), buttock (2), inguinal region (1); heart (12); and extremities (7). The proven predisposing risk factors included chronic pyothorax for angiosarcoma in the pleural cavity (six), thorotrast in the liver (five), radiotherapy to the abdominal wall and buttock (four), and chronic limb edema of the forearm (one). Irrespective of primary sites, the majority of cases had metastases to lung in 72 cases, bone in 42, liver in 36, regional lymph nodes in 30, and adrenal gland in 24. The 2-year survival rate was 17%. CONCLUSIONS: This study describes a different etiology in the development of angiosarcoma in patients from Japan compared with that of patients from Western countries, though the frequency of angiosarcoma among all soft-tissue sarcomas was similar in both areas. In Japan, chronic pyothorax, radiotherapy, and thorotrast proved to be distinctive causative factors of angiosarcoma.

Adolescent↗