Association of Loss of Heterozygosity at the p53 Locus with Chemoresistance in Osteosarcomas

Although the osteosarcoma is considered to be among the most chemosensitive malignancies and preoperative chemotherapy is commonly applied, an appreciable proportion of cases are in fact quite insensitive. Predictive markers for chemosensitivity are therefore desirable in order to develop effective treatment strategies. Thirty-two cases of conventional osteosarcomas treated at the Cancer Institute Hospital, Tokyo, were analyzed. The sensitivity to preoperative chemotherapy was investigated with reference to loss of heterozygosity (LOH) at the 17p13 ( p 53) and 13q14 ( Rb ) loci and expression of the cell-cycle associated proteins, p53, Rb, p21/Waf-1, mdm-2 and Ki-67, as detected immunohistochemically. LOH was detected by analyzing polymerase chain reaction products at marker microsatellite loci. The efficacy of chemotherapy was evaluated both radiologically and histologically. LOH at p 53 or Rb loci was seen in 54% (13/24) and 58% (14/24) of cases, respectively. Only 15% of osteosarcomas with LOH at the p 53 locus were sensitive to preoperative chemotherapy, as compared to 64% of tumors without such loss ( P <0.05). A similar but much less distinct tendency was observed with LOH at the Rb locus. No relationship was evident between chemosensitivity and immunohistochemical staining patterns for p53, Rb, p21/Waf-1, mdm-2 or Ki-67. The results suggest that p 53 gene deletion, but not the other parameters investigated, may be useful for predicting chemoresistance of osteosarcomas.     

Antitumor Immunity Induction by Intracellular Hyperthermia Using Magnetite Cationic Liposomes

Induction of antitumor immunity to T-9 rat glioma by intracellular hyperthermia using functional magnetic particles was investigated. Magnetite cationic liposomes (MCLs), which have a positive surface charge, were used as heating mediators for intracellular hyperthermia. Solid T-9 glioma tissues were formed subcutaneously on both femurs of female F344 rats, and MCLs were injected via a needle only into the left solid tumors (treatment side). The rats were then divided into two groups, which received no irradiation, or irradiation for 30 min given three times at 24-h intervals with an alternating magnetic field (118 kHz, 384 Oe). On the treatment side, the tumor tissue disappeared completely in many rats exposed to the magnetic field. The tumor tissue on the opposite side also disappeared completely, even though MCLs were not injected into the right solid tumors. To examine whether a long-lasting and tumor-specific immunity could be generated, the rats that had been cured by the hyperthermia treatment were rechallenged with T-9 cells 3 months later. After a period of transient growth, all tumors disappeared. Furthermore, immuno-cytochemical assay revealed that the immune response induced by the hyperthermia treatment was mediated by both CD8⁺ and CD4⁺ T cells and accompanied by a marked augmentation of tumor-selective cytotoxic T lymphocyte activity. These results suggest that our magnetic particles are potentially effective tools for hyperthermic treatment of solid tumors, because in addition to killing of the tumor cells by heat, a host immune response is induced.     

Mutation Analysis of the WT1 Gene in Myelodysplastic Syndromes

The WT1 tumor suppressor gene was examined for mutations in a panel of 44 patients with myelo-dysplastic syndromes (MDS) including acute myelogenous leukemias (AML) secondary to MDS, using polymerase chain reaction single-strand conformation polymorphism (PCR-SSCP) analysis and sequencing analysis. A WT1 mutation was detected in one out of 17 cases of AML secondary to MDS. This mutation exists upstream of the zinc finger region and is predicted to produce a truncated WT1 protein lacking the zinc finger region. No mutations were detected in 27 MDS patients who had not progressed to AML. This is the first report of analysis for WT1 mutations in a large number of MDS patients, suggesting that WT1 mutations are uncommon in MDS. Abnormalities in this gene may, however, contribute to a small proportion of cases showing progression from MDS into AML.     

Tumor-specific Activation of Mitogen-activated Protein Kinase in Human Colorectal and Gastric Carcinoma Tissues

To search for the signaling events in colorectal carcinoma relevant to its tumorigenesis, we investigated the activity of mitogen-activated protein kinase (MAPK) in human colorectal carcinoma tissues and paired normal tissues. Of 64 cases examined, approximately 75% (48 cases) showed tumor-specific activation of MAPK by in situ kinase renaturation assay, as well as in vitro kinase assay with immunoprecipitated MAPK. In addition, tumor-specific activation of MAPK was associated with the activation of MAPK kinase in the cases we examined. However, no clear correlation of MAPK activation with lymph node involvement, metastatic rate, stage, histological classification, age or sex was observed. These results suggest that the MAPK pathway is involved in colorectal tumor development, but its activation alone is not sufficient for malignant conversion. In contrast to colorectal carcinoma, gastric carcinoma tissues showed a lower rate of MAPK activation, suggesting that the signaling pathway activated in colorectal carcinoma tissues may differ in part from that of gastric carcinoma.     

Selection of Human Ovarian Carcinoma Cells with High Dissemination Potential by Repeated Passage of the Cells in vivo into Nude Mice, and Involvement of Lex-determinant in the Dissemination Potential

Cells of the human tumor cell line RMG-1, derived from a clear-cell adenocarcinoma of the ovary, were injected intraperitoneally into nude mice, and the cells obtained from the tumor nodules in the mesenterium were found to form a larger number of, and larger-sized, tumor nodules than the original RMG-1 cells. The RMG-1-h cells, transferred into culture from the tumor nodules after a 4th in vivo passage, showed a dissemination potential as high as that of cells disseminating directly from the tissues, and exceedingly higher than that of RMG-1 cells. To assess the molecular bases of the different biological properties of RMG-1 and RMG-1-h cells, we compared the content and expression of various carbohydrate antigens in both cells. The chromosomal profile of RMG-1-h cells revealed their human origin and was identical to that of the original RMG-1 cells. In contrast to the broad histogram for the Le^x-bearing cells among RMG-1 cells in flow cytometry, the weakly and moderately positive cells toward anti-Le^x antibody were found to be eliminated from the histogram for the RMG-1-h cells, resulting in the enrichment of cells strongly expressing Le^x, which may account for the high dissemination potential. In addition, the adhesion of RMG-1 cells to mesothelial cells was found to be significantly inhibited by pretreatment of the cells with anti-Le^x antibody, indicating Le^x-mediated cell-to-cell interaction between ovarian cancer cells and mesothelial cells. By TLC-immunostaining, two Le^x-glycolipids, III³Fucα-nLc₄Cer and V³Fucα-nLc₆Cer were detected in both RMG-1 and RMG-1-h cells, and their total concentrations were not significantly different from each other. However, the hydrophobic moieties of Le^x-glycolipids in RMG-1-h cells were different from those in RMG-1 cells, suggesting that a difference in the structure of the hydrophobic moieties of Le^x is partly involved in the enhanced reactivity of RMG-1-h cells toward anti-Le^x antibody. Thus, the high dissemination potential of ovarian cancer cells was shown to be mediated by the Le^x-determinant and the Le^x-bearing cells are enriched by repeated in vivo passage of the cells into nude mice.     

Potentiation of Paclitaxel Cytotoxicity by Inostamycin in Human Small Cell Lung Carcinoma, Ms-1 Cells

In the present study, we found that inostamycin increased the ability of paclitaxel to induce apoptosis in Ms-1 cells. A considerably higher concentration of paclitaxel was required for the induction of apoptosis in Ms-1 cells than in other cell lines tested. Treatment of Ms-1 cells with inostamycin, an inhibitor of phosphatidylinositol (PI) synthesis, reduced the dosage of paclitaxel required to induce cell death by apoptosis. This effect of inostamycin is specific to Ms-1 cells, and inostamycin did not increase the cytotoxicity of other antitumor drugs such as adriamycin, vinblastine, methotrexate, cisplatin, etoposide, or camptothecin in Ms-1 cells. Addition of inostamycin to paclitaxel-treated cells caused a significant increase in the sub G1 peak, representing apoptosis, which was accompanied by a decrease in the G2/M peak seen in paclitaxel-treated Ms-1 cells, without affecting paclitaxel-inhibited tubulin depolymerization. Moreover, paclitaxel did not enhance inostamycin-inhibited PI synthesis. The expression levels of Bcl-2, Bax, and Bcl-X_L were not changed following the co-treatment with inostamycin plus paclitaxel, whereas the activated form of caspase-3 was markedly increased. Thus, inostamycin is a chemosensitizer of paclitaxel in small cell lung carcinoma Ms-1 cells.     

CT图像中噪声产生机理与维修

本文重点阐述和分析了CT图像中的几种噪声产生的原因和对图像的影响,并结合笔者多年的维修经验,从理论和实际相结合,介绍了几种实用的维修方法,提出了减小噪声提高图像质量的有效措施。     

Nephrolithiasis associated with autosomal dominant polycystic kidney disease: contemporary urological management

PURPOSE: We evaluate the role of contemporary urological intervention in patients with nephrolithiasis associated with autosomal dominant polycystic kidney disease. MATERIALS AND METHODS: Intervention for upper tract stones associated with autosomal dominant polycystic kidney disease was performed in 5 women and 2 men 29 to 65 years old (mean age 47). Indications for intervention consisted of flank pain in 6 patients and/or hematuria in 2. A total of 12 procedures (mean 1.7 per patient) were performed, including shock wave lithotripsy in 6 patients, percutaneous nephrolithotomy in 2, retrograde endoscopy or manipulation in 3 and extended pyelonephrolithotomy in 1. RESULTS: All patients were rendered stone-free or had only residual "dust." Hospital stay for 5 patients was 1 night or less and there were no complications. Renal function for each patient was stable or improved as measured by serum creatinine. CONCLUSIONS: Most patients with autosomal dominant polycystic kidney disease who require intervention for nephrolithiasis can be safely and effectively treated with essentially any or all contemporary, minimally invasive techniques. The choice of intervention can be based primarily on size and location of the upper tract stones rather than the associated presence of polycystic kidneys.     

Variation in clinical outcome following shock wave lithotripsy

PURPOSE: We measure and compare operator specific success rates of extracorporeal shock wave lithotripsy (ESWL) performed by 12 urologists in 1 unit to determine interoperator variation. MATERIALS AND METHODS: From January 1, 1994 to September 1, 1997 a total of 5,769 renal and ureteral stones received 9,607 ESWL treatments by 15 urologists with a Dornier MFL 5000 lithotriptor. The 3-month followup data are available for 4,409 stones. Outcome measures consisted of patient demographics, stone characteristics, technical details of lithotripsy, and stone-free and success rates by treating urologists. RESULTS: Treatment results were analyzed for 12 urologists (surgeons A to L) who treated more than 100 stones each, totaling 4,244 with followup information available. Mean stone-free and success rates were 50.6% and 72.3%, respectively. Surgeon A had significantly higher stone-free and success rates of 56.2% and 76.7%, respectively (p<0.05), with treatment results from 877 stones, which was a significantly higher number than others (p<0.05). Significant differences existed in mean number of shocks delivered among urologists (p = 0.0001), with surgeons A and J delivering the highest mean numbers (2,317 and 2,801, respectively). There was no difference in treatment duration (p = 0.75) but variation existed among urologists in terms of mean maximum treatment voltage (p = 0.0001). Mean fluoroscopy time at 4.1 minutes was higher for surgeon A than others (p<0.05). Mean complication rate following ESWL was 4.9% with no difference among urologists (p = 0.175). Re-treatment was required in 21.7% of cases and surgeon A had the lowest rate (15.9%, p<0.05). CONCLUSIONS: We demonstrated clinically and statistically significant intra-institutional differences in success rates following ESWL. The best results were obtained by the urologist who treated the greatest number of patients, used a high number of shocks and had the longest fluoroscopy time. Accurate targeting is crucial when using a lithotriptor, such as the Dornier MFL 5000, with a narrow focal zone of 6.5 mm. in diameter. Other centers should be encouraged to develop similar programs of outcome analysis in an attempt to improve performance.