LET Dependence of 8-Hydroxy-2'-deoxyguanosine (8-OHdG) Generation in Mammalian Cells under Air-Saturated and Hypoxic Conditions: A Possible Experimental Approach to the Mechanism of the Decreasing Oxygen Effect in the High-LET Region.

One of the most distinguished features in biological effects of heavy ions would be the decrease of oxygen effect in the high-LET region. This feature has been referred to as the radiobiological basis for the control of hypoxic fraction in cancer radiotherapy. However, mechanisms to explain this phenomenon have not been fully understood. One of the explanations was given by the oxygen in the track hypothesis, which proposes that oxygen is produced along ion tracks even in the hypoxic irradiation condition. In the present study, we designed an experimental approach to support this hypothesis by using 8-hydroxy-2'-deoxyguanosine (8-OHdG) as DNA damage requiring oxygen to produce. The LET dependence of 8-OHdG under hypoxic condition revealed that with increasing LET 8-OHdG yield seems to increase, despite that the yield of OH radical, which is also required for the production of 8-OHdG, decreases in the high-LET region. This result is consistent with the explanation that the local generation of oxygen along ion tracks contributes to the increase of 8-OHdG yield.

DOSE-RATE AND CELL-KILLING SENSITIVITY OF HIGH-LINEAR ENERGY TRANSFER ION BEAM.

It is believed that the dose-rate of radiation will have an influence on cell sensitivity. The dose-rate effects on cell survival can be expressed by the change of the ß term in the linear quadratic model. The value at a high-dose-rate decreases below 60 Gy/h and reaches zero at 0.2 Gy/h or less for photons. However, the effect for a high-LET ion-beam is not well known. At HIMAC, cells were exposed to 70 keV/µm carbon-ion beams at different dose-rates between 0.5 and 600 Gy/h at room temperature. The ß values for all survival curves show no significant differences among the dose-rates tested for HSG, V79 and CHO cells. Changing the ion-beam dose-rate had no effect on cell survival. This suggests that high-LET particle beams, such as galactic cosmic rays, may not exhibit a dose-rate effect on cell survival. Low-dose-rate radiation showed an effect similar to high-dose-rate radiation.

[Case with cardiac myxoma causing cerebral metastasis after cardiac tumor resection].

We report a case of cardiac myxoma causing cerebral metastasis after cardiac tumor resection. A 68-year-old man with a cerebral infarction was admitted to our hospital. A cardioembolic source was suspected and echocardiography was performed. In that examination, a cardiac tumor was found in the left atrium. Tumor resection was performed urgently and his postoperative course was uneventful. After the operation he had no new episodes of cerebral deficit. However 6 months after the operation, he complained of headaches. The brain computed tomography (CT) showed there were multiple high-density areas. One of the tumors was resected and the tumor was diagnosed pathologically as metastasis of cardiac myxoma. Brain metastases were treated with 40.8 Gy whole-brain radiation therapy. As the result the tumors were effectively treated and reduced.

Adaptation of the microdosimetric kinetic model to hypoxia.

Ion beams present a potential advantage in terms of treatment of lesions with hypoxic regions. In order to use this potential, it is important to accurately model the cell survival of oxic as well as hypoxic cells. In this work, an adaptation of the microdosimetric kinetic (MK) model making it possible to account for cell hypoxia is presented. The adaptation relies on the modification of damage quantity (double strand breaks and more complex lesions) due to the radiation. Model parameters such as domain size and nucleus size are then adapted through a fitting procedure. We applied this approach to two cell lines, HSG and V79 for helium, carbon and neon ions. A similar behaviour of the parameters was found for the two cell lines, namely a reduction of the domain size and an increase in the sensitive nuclear volume of hypoxic cells compared to those of oxic cells. In terms of oxygen enhancement ratio (OER), the experimental data behaviour can be reproduced, including dependence on particle type at the same linear energy transfer (LET). Errors on the cell survival prediction are of the same order of magnitude than for the original MK model. Our adaptation makes it possible to account for hypoxia without modelling the OER as a function of the LET of the particles, but directly accounting for hypoxic cell survival data.

Overexpression of nm23-H2/NDP kinase B in a human oral squamous cell carcinoma cell line results in reduced metastasis, differentiated phenotype in the metastatic site, and growth factor-independent proliferative activity in culture.

The metastasis suppressor activity of nm23/nucleoside diphosphate (NDP) kinase was assessed using human oral squamous cell carcinoma (SCC) cell lines. When the expression of nm23/NDP kinase was compared among several SCC cell lines, nm23-H2/NDP kinase B gene product, but not nm23-HI/NDP kinase A gene product, was reduced in the metastatic cells. Transfection of nm23-H2 into the metastatic SCC cell line LMF4 caused reduction in the lung metastasis in an experimental metastasis assay. A histological analysis of the pulmonary metastatic foci revealed that although foci of the control clones were composed of anaplastic squamous cells, those of the nm23-H2-transfected clones consisted of mostly well-differentiated cells mimicking normal stratified epithelial constitution. The transfected cells were morphologically indistinguishable from the control ones in culture, but they differed from each other in that the former cells proliferated faster than the latter, became less serum dependent, and lost responsiveness to growth factors such as platelet-derived growth factor, insulin-like growth factor I, and insulin, although both clones retained sensitivity to transferrin. These results demonstrate that nm23-H2 protein does have metastasis suppressor activity for human SCC cells and suggest that this activity may be elicited by modulating growth and/or differentiation potential in response to environmental factors.

Differential effect of host microenvironment and systemic humoral factors on the implantation and the growth rate of metastatic tumor in parabiotic mice constructed between young and old mice.

B16 melanoma cells were injected into the tail vein of young mice, old mice and parabiotic mice constructed between young and old mice, and the number and shape of pulmonary metastases were compared among three experimental groups. In unpaired mice, the number of metastatic colonies in the lungs was 10-fold larger in young than in old mice. In parabiotic mice, the number in young mice was almost comparable with that of unpaired young mice, but the number in old mice approached the level of young mice. Metastatic colonies on the pulmonary surface of young mice were mostly nodular in shape, while those of old mice were flat in shape. The shape of colonies reflecting the tumor growth rate did not change in parabiotic old mice in spite of an increase in number. In young parabiotic mice, the large and intermediate colonies decreased with a concomitant increase of small ones as compared with unpaired young mice. These results suggest that the implantation of metastatic colonies in the lung is mainly dependent on systemic humoral factors and their growth is mainly dependent on the host local factors in the microenvironment, and distinct age changes of both factors greatly influence the metastatic mode of tumors, respectively.

Insulin sensitizer YM268 ameliorates insulin resistance by normalizing the decreased content of GLUT4 in adipose tissue of obese Zucker rats.

Genetically obese Zucker rats exhibit mild hyperglycaemia and hyperinsulinaemia suggesting the existence of peripheral insulin resistance. We have examined the effects of YM268, an analogue of thiazolidinedione, on the content and translocation of a glucose transporter (GLUT4) in epididymal adipose tissue in 11-week-old obese and lean Zucker rats. The administration of YM268 at a dose of 10 mg/kg for 2 weeks ameliorated hyperglycaemia, hyperinsulinaemia, and impaired glucose tolerance after glucose load in obese rats. The GLUT4 content per fat pad in obese rats was reduced to 36% of that in lean littermates. Obese rats treated with YM268 increased GLUT4 concentrations in their fat pads from a basal value of 36% up to 191% of the level in lean rats. Furthermore, in adipocytes prepared from obese rats, an increase in the ratio of GLUT4 in plasma membrane to the total amount of GLUT4 (PM-GLUT4 ratio) induced by the submaximal concentration of insulin (0.3 nmol/l) was significantly attenuated compared with that in lean rats. But the maximum effect of insulin (3 nmol/l) was not attenuated. Meanwhile, YM268 had no significant effect on the attenuated PM-GLUT4 ratio in response to insulin in obese rats. These data suggested that one of the mechanisms by which YM268 improved insulin resistance in obese Zucker rats was to normalize the decreased GLUT4 content in the adipose tissue.

Telomere shortening in gastric carcinoma with aging despite telomerase activation.

In the present study, we analyzed both telomere length and telomerase activity in surgical and autopsy samples of non-neoplastic mucosa and carcinomas of the stomach. Telomere length, determined by Southern blot analysis, demonstrated progressive shortening with age in non-neoplastic gastric mucosal specimens from 38 human subjects aged between 0 and 99 years, with an average annual loss rate of 46 base pairs (bp). The mean (+/- SD) telomere length in 21 gastric carcinomas was 7.0 +/- 1.6 x 10(3) base pairs (1.6 kbp). In 20 (95%) of the 21 subjects, the values were smaller than those in the nonneoplastic gastric mucosa (mean shortening 1.8 kbp), although a strong correlation was observed for the paired data (r = 0.69, P = 0.0004). Similarly, telomere lengths in carcinomas were shorter than those for intestinal metaplasia (a mean difference of 1.1 kbp). Telomerase activity, estimated using the telomeric repeat amplification protocol assay, was positive in 18 (86%) of the 21 gastric carcinomas, without significant differences among the three histological types (well, moderately, and poorly differentiated adenocarcinomas) or with sex or age. The results suggest that telomere length and possibly shortening rates vary with the individual, and that examination of both non-neoplastic mucosa and tumors is necessary to improve our understanding of the significance of telomerase in neoplasia.

The novel hypoglycemic agent YM440 normalizes hyperglycemia without changing body fat weight in diabetic db/db mice.

To determine the relationship between hypoglycemic activity and body weight gain induced by insulin sensitizers, we compared the effects of thiazolidinedione analogs (troglitazone and pioglitazone) and the oxadiazolidinedione analog (Z)-1,4-bis4[(3,5-dioxo-1,2,4-oxadiazolidin-2-yl)methyl]phen oxy¿but-2-ene (YM440) in diabetic db/db mice. Oral treatment with YM440(100 mg/kg) for 28 days decreased the blood glucose concentration (control v YM440, 418 +/- 12 v243 +/- 44 mg/dL). The hypoglycemic activity of this agent was comparable to that of troglitazone (300 mg/kg) and pioglitazone (100 mg/kg). There were no changes in food intake among the groups. Troglitazone and pioglitazone, but not YM440, significantly increased body weight gain during treatment (control, 7.2 +/- 0.5 g; YM440, 7.5 +/- 0.8 g; troglitazone, 10.9 +/- 0.8 g; and pioglitazone, 14.5 +/- 1.1 g). To further assess whether the increase in body weight by troglitazone or pioglitazone was due to adipogenesis, the weight of intraabdominal fat tissue (epididymal, retroperitoneal, and perirenal) was determined. There were no differences in the total weight of visceral fat between the control and YM440 treatment (3.53 +/- 0.23 and 3.60 +/- 0.16 g). In contrast, troglitazone and pioglitazone significantly increased the fat weight (4.31 +/- 0.13 and 4.66 +/- 0.19 g). Thiazolidinediones are known as ligands for peroxisome proliferator-activated receptor gamma (PPARgamma), a nuclear receptor responsible for adipogenesis. Troglitazone and pioglitazone activated PPARgamma and increased triglyceride accumulation and mRNA expression of fatty acid-binding protein (FABP) in 3T3-L1 cells. However, YM440 had no effect on these indices for adipocyte differentiation. These results suggest that the mechanism is different for the hypoglycemic action of YM440 versus the thiazolidinediones. YM440 ameliorates hyperglycemia without changing PPARgamma activity, adipocyte differentiation, or fat weight. Thus, YM440 could be a useful hypoglycemic agent for the treatment of non-insulin-dependent diabetes mellitus (NIDDM) without affecting body weight.

Thymidylate synthase gene expression in primary colorectal cancer and metastatic sites.

Thymidylate synthase (TS) expression has been identified as an important predictor of response to 5-fluorouracil (5-FU). However, there is relatively little information on the heterogeneity of TS mRNA expression between primary and metastatic tumors, as well as differential expression of TS mRNA in metastatic sites. In this study, TS mRNA expression was measured in primary colorectal cancer tumors and various metastatic tumors. The median TS/glyceraldehyde-3-phosphate dehydrogenase (GAPDH) mRNA ratio was 0.98 in primary tumors, 0.70 in liver metastases, 1.92 in lymph node metastases, and 3.42 in pulmonary metastases. A significantly higher expression of TS mRNA was observed in pulmonary and lymph node metastases compared with their respective primary tumors. In contrast, TS mRNA expression in hepatic metastases was significantly lower than in primary tumors. Similar results were observed in tumors obtained from the same patient. These results may explain the difference in the clinical response to 5-FU-based chemotherapy between various metastatic sites. The discordant TS expression between primary and metastatic tumors is a critical factor that must be taken into account when TS is being used as a predictive biomarker for the antitumor effect of 5-FU-based chemotherapy.

Comparison by carcinoembryonic antigen doubling time of hepatic injection and infusion for unresectable hepatic metastasis from colorectal cancer.

This study explored the efficacy of hepatic arterial therapy, comparing both injection and infusion of 5-fluorouracil (5-FU) in prolonging the survival of 92 patients with recurrent unresectable hepatic metastasis from colorectal cancer. With respect to pretreatment carcinoembryonic antigen doubling time (CEA-DT), 56 patients were treated with intra-arterial injection, and 36 with intra-arterial infusion. In 21 patients with a CEA-DT of less than 40 days, the cumulative survival of patients treated with arterial injection was significantly longer than that of patients treated with arterial infusion. In 45 patients with a CEA-DT of 40-80 days, the survival curves of patients did not differ from each other. Of the remaining 26 patients with a CEA-DT of more than 80 days, those treated using arterial infusion had an excellent prognosis, in contrast to those treated using arterial injection, with statistical significance. CEA-DT may be useful when choosing a chemotherapy regimen, and may help to accurately establish the prognosis of patients with unresectable hepatic metastasis from colorectal cancer.

Estimation of glycogen levels in human colorectal cancer tissue: relationship with cell cycle and tumor outgrowth.

In this study, we quantitatively measured glycogen levels in tissue samples obtained from tumors, regions adjacent to tumor, and regions of normal colorectum to determine whether the levels were related to cell cycle and cancer growth. Glycogen levels were analyzed in relation to histopathological factors, (tumor size and stage of disease) and cell cycle progression. The glycogen level was found to be highest in the cancer tissue, lower in normal tissue, and lowest in the adjacent tissue. The difference in glycogen level between the cancer tissue and the other two regions was significant (P < 0.05). There was a negative correlation between glycogen level and tumor size, but it was not significant. The level of glycogen in cancer tissues decreased as the stage of the disease progressed, but a significant difference was not found between stages. There was a negative correlation between the glycogen level and the proliferation index. There was a positive correlation between the glycogen level and the proportion of cancer cells in G1 phase, while there was a negative correlation with S and G2M phases. Glycogen levels were highest in cancers with a high proportion of cells in G1, and decreased with progression to S phase. It may be that glycogen is utilized in the progression to S phase, and the cancer tissues are supplied with glycogen from the tumors themselves as well as their adjacent tissues. Cancer growth may be inhibited by artificial control of the glycogen level in the G1 phase of cancer cells.

Access to the emergency psychiatry system in Japan.

Although the need for an emergency psychiatry system is increasing in Japan because of a shift to providing psychiatric care from hospitalization to community-based services, little attention is being given to what the general population expects from the health care system. To ascertain the expectations of the general population about how emergency psychiatric cases should be handled, the authors distributed a questionnaire to 1000 people containing 12 characteristic psychiatric emergency cases. The results showed that most expected psychiatric care to be rendered in a general hospital. This was different from the opinion held by most mental health professionals who felt that mental health hospitals should be the core hospitals of emergency psychiatry. Although there was a higher expectation for police officers or paramedics to provide emergent psychiatric care, the general population expected less from public health centers which now provide mental health service in the community. To connect emergency psychiatry with the community, the general hospital must play a larger role in the system through training programs for general hospital psychiatrists as well as nonpsychiatrist professionals, paramedics, and police officers.

Angiosarcoma of the breast: report of a case and its findings of MRI.

A 67-year-old woman with angiosarcoma of the left breast is presented. Physical findings showed a hard mass in the left breast with skin discoloration and erythema. Mammography showed a high density shadow in the mass without microcalcification and spicula. On ultrasonography, a hypoechoic mass with an ill-defined boundary was detected. On MRI, the tumor had low signal intensity on T1-weighted images, and higher signal intensity on T2-weighted images. MRI with Gd-DTPA images showed higher signal intensity on T1-weighted images with relatively lower intensity in the central area of the tumor. The artery supplying the tumor derived from the left inner thoracic artery and was visualized on three-dimensional dynamic MRI angiography. Initially misdiagnosed as inflammatory breast cancer, an arterial injection of CPA (100 mg) and 5-FU (500 mg) had been performed preoperatively. The definitive diagnosis of angiosarcoma was established by intraoperative frozen section examination. She underwent modified radical mastectomy and is now free of recurrence. This case emphasizes the difficulties in the clinical diagnosis of angiosarcoma of the breast.

[A case of nonresectable advanced gastric cancer responding to combined chemotherapy with 5'-DFUR, CDDP, and MMC].

A 39-year-old man was referred for epigastric fullness and a mass in the umbilical region. A giant mass was palpated in the epigastric region, while a mass 1 cm in diameter with a hemorrhagic tendency was felt in the umbilical region. Fluoroscopy of the upper gastrointestinal tract and gastroscopy revealed a Borrmann 3 tumor in the upper part of the gastric corpus. The tumor was found by CT scanning to be growing clearly across the wall of the stomach, and the invasion to the transverse colon was suspected by the enema. The tumor was unresectable because of the extensive tumor invasion of the abdominal wall. Therefore, the patient received 2 courses of combined chemotherapy with 5'-DFUR, CDDP, and MMC. As a result, the tumor in the epigastric region was reduced dramatically, and it became unpalpable 6 months after treatment. At the same time, the tumor in the umbilical region disappeared. Both CT scanning and upper gastrointestinal radiography disclosed tumor reduction, and sufficient oral ingestion became possible. The administration of 5'-DFUR has since been continued as maintenance therapy. Aside from transient anorexia and slight leukopenia, the patient developed no symptoms during the treatment period. At present. 2 years and 9 months after starting chemotherapy, the patient is in good health.

[Studies on the effect of lentinan on human immune system. II. In vivo effect on NK activity, MLR induced killer activity and PHA induced blastic response of lymphocytes in cancer patients].

Immunological activities of lymphocytes were studied in patients with cancer of digestive organs and mamma after administration of lentinan. When 11 cancer patients received lentinan i.v. 2 mg, NK activity of lymphocytes was increased in 4 patients on the following day. With the same condition, MLR induced killer activity against Raji cell of lymphocytes was increased in 3/7 patients and PHA response was also increased in 3/7 patients. These activities were returned to values before the administration of lentinan. Then each activity was examined after administration of lentinan twice a week. NK activity, MLR induced killer activity and PHA response were increased in 4/15, 8/12 and 5/11 patients, respectively.

[Maximum tolerated dose of tegafur in rats].

Maximum Tolerated Dose of Tegafur was estimated by per-oral administration in male Donryu rats. Tegafur was administered for 24 weeks at respective doses of 90 mg, 120 mg and 150 mg/kg/day. Six of 10 (60%) died during the treatment in those groups administered with 120 mg and 150 mg/kg/day, respectively. The cause of death of these rats was severe pneumonia. All 10 of the group given 60 mg/kg/day survived until end of the administration and were sacrificed for histological examination of organs. These rats showed apparent suppression of body weight gain compared with controls (p less than 0.001). Slight inflammation of the lungs was observed in all rats, congestion of the liver and local degeneration and necrosis of the liver cells in a few rats and cellular degeneration of bone marrow in one rat. There was no remarkable change in the digestive tract, kidney, thymus or reproductive organs. Accordingly, the Maximum Tolerated Dose of Tegafur was determined to be 90 mg/kg/day.

[Preoperative intra-arterial injection of mitoxantrone for locally advanced breast cancer].

Mitoxantrone (MIT) is a new anthraquinone anti-cancer agent. We successfully treated 3 patients with locally advanced breast cancer, including two inflammatory breast cancers, by pre-operative arterial injection of MIT. The treatment protocol was MIT 12 mg/m2 injected into both the internal mammary and the subclavian artery with oral administration of 5' DFUR 1,200 mg/day. In two cases of inflammatory breast cancer, the redness of skin was immediately reduced after the first course. After 2 courses, all tumors were decreased over 50% in size. Standard radical mastectomy could be carried out on all patients. Preoperative arterial injection of MIT might be the treatment of choice for locally advanced breast cancer. This preliminary result encourages further study.

[Clinical study on the effect of intra-arterial injection of mitoxantrone-lipiodol emulsion for hepatocellular carcinoma].

To investigate the effect of intra-arterial injection of mitoxantrone emulsified with ethiodized oil, forty-eight patients with hepatocellular carcinoma were evaluated. After the treatment, ten of the patients underwent hepatectomy. In the thirty-eight unresected cases, there were 15 (39%) partial responses, which continued 1.2 to 11.8 months (mean, 5.8 months). The 1- and 2- year survival rates were 67% and 38%, respectively. The response rate was higher in cases with tumor under 5 cm in diameter. In the remaining 10 resected cases, the necrotic areas in main nodules ranged from 65% to 100% (mean, 85%). This treatment might be applied effectively to patients with small hepatocellular carcinoma.

[Successful preparation of mitoxantrone emulsion containing non-ionic contrast medium].

Mitoxantrone, a new anti-cancer agent, was successfully prepared for Lipiodol emulsion. The mixture of Mitoxantrone and non-ionic contrast medium, Omnipaque 300, was combined with Lipiodol at the ratio of 1:2. When the ratio of Mitoxantrone and Lipiodol was 1:4, microscopic study revealed stabilized water in oil emulsion, which could release the anti-cancer agent slowly. We applied it for a case of hepatocellular carcinoma with good result. Intra-arterial infusion of this emulsion might be considered effective for treatment of hepatocellular carcinoma.