摘要:

AbstractHuman T‐cell leukemia virus type I (HTLV‐1) is the etiologic agent for adult T‐cell leukemia (ATL). Among the X region products of HTLV‐1, the p42 kDa protein Tax was identified, as responsible for cell immortalization and transformation. However, the observations that only a low percentage of individuals infected with HTLV‐1 eventually progress to leukemia and that leukemic transformation of HTLV‐1‐infected cells is associated with aberrant karyotype suggest that additional genetic events are required for HTLV‐1‐induced malignant transformation. Results of our study demonstrate that expression of the Tax protein of HTLV‐1 increased the radiosensitivity of a mouse fibroblast cell line. These data are consistent with a previous report indicating a negative regulatory control by Tax on DNA repair. Unrepaired DNA damage and karyotypic instability could represent a common factor in both the initiation and progression of HTLV‐1‐related diseases.

ISSN:1065-7541    

DOI:10.1002/roi.2970010302

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1993

数据来源: WILEY

摘要:

AbstractThere is a need for radiosensitizers, to be used in conjunction with fractionated radiotherapy (∼2 Gy), because of the resistance of the hypoxic portions of tumors. A marked selective interaction between cisplatin (cis‐diamminedichloroplatinum (II)) and low doses of radiations was reported in hypoxic cells [Korbelik and Skov: Radiat Res 119:145–156, 1989]. A first hypothesis might be the interference with repair of radiationinduced DNA breaks by cisplatin, or vice versa. In order to study these possible mechanisms of interaction, the effects of changing the delivery time of cisplatin before and after low‐dose X‐irradiation of hypoxic cells were investigated. Survival after low doses of X‐rays of both Chinese hamster ovary (CHO) and V79 cells growing exponentially was assessed using the Cell Analyzer for location of individual cells. In cells exposed to cisplatin (2.5 μM for 1 hr) and low doses of X‐rays in hypoxia, the pronounced enhancement ratio (ER; 1.7 in CHO, 1.8 in V79) did not decrease regardless of scheduling (up to 8 hr after or 3 hr before irradiation). Since the repair of single‐strand breaks (SSB) is rapid, it appears that interference with their repair is not a major contribution to the interaction. The longer‐term damage (or misrepair) was examined indirectly by looking at 1) colony size: CHO cells which were irradiated with low doses of X‐rays (1 Gy, hypoxia) or treated with cisplatin (2.5 μM) produced smaller colonies than controls; the data for the combined treatments are presented, and 2) chromosome aberrations in hypoxic CHO cells: the ER for exchanges agrees with the survival data.

ISSN:1065-7541    

DOI:10.1002/roi.2970010303

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1993

数据来源: WILEY

摘要:

AbstractWe obtained peripheral lymphocytes from both healthy donors (n = 7) and cancer patients (n = 14) for the cytokinesis‐blocked micronucleus (MN) assay. Lymphocytes were irradiated with137Cs to 2 Gy. Cytochalasin B (6 μg/ml) was added to the incubation at 44 hr and the cells were harvested at 72 hr. We found that compared to healthy donors, lymphocytes of cancer patients revealed no significant difference in the MN baseline level (P= 0.86). Apparently DNA damage manifested as MN in the lymphocytes of cancer patients is not more severe than that of healthy donors. In addition, 2 Gy in vitro irradiation of lymphocytes caused no difference in the MN formation between cancer patients and healthy donors (P= 0.9). Radiation induced cell cycle delay as evaluated by the number of mononucleate, binucleate, and cells with>2 nuclei and by the mitotic indices showed similar results in both populations. However, the difference for MN frequency in lymphocytes before and after 2 Gy in vitro irradiation was highly significant for both cancer patients and healthy donors (P = 0.0001). These studies in general indicate that the MN frequency in cytochalasin B‐blocked human lymphocytes has the potential of serving as a quantitative biological dosimeter for the screening of radiation exposure to either healthy individuals or cancer patients. © 1993 Wiley‐Li

ISSN:1065-7541    

DOI:10.1002/roi.2970010304

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1993

数据来源: WILEY

摘要:

AbstractThe hypothesis that hypoxia may be present in the intraductal component associated with infiltrating breast cancer was tested by studying the morphology of the intraductal component with respect to expansion of the tumor‐filled breast ducts and intraductal necrosis. Of 52 consecutive patients with T1–2N0–1M0infiltrating ductal breast carcinoma, 10 had an extensive intraductal component (EIC), 27 had a limited intraductal component (LIC), and 15 had no intraductal component. The necrosis‐containing comedo‐ and cribriform‐predominant types of intraductal carcinoma were common (50%) in the EIC group, but infrequent (19%) in the LIC group. The frequency of intraductal necrosis increased with duct diameter. Seventy‐five percent of ducts with a radius exceeding the oxygen diffusion distance (>180 μm) contained necrosis compared with 33% of ducts below that size. The average duct diameter was significantly larger (404 μm;P= 0.0056) and intraductal necrosis was more common (61%) in the EIC group than in the LIC group (263 μm; 33%). All patients with local recurrence in the EIC group (20%) had the comedo‐predominant pattern, with a high percentage (79%) of necrotic ducts. The increasing frequency of intraductal necrosis with increasing duct size, particularly with radii of more than 180 μm, suggests that tumor cell hypoxia is present in the intraductal component. The larger duct size and higher frequency of necrosis in the EIC group suggest that hypoxia is more common in EIC than in LIC. ©

ISSN:1065-7541    

DOI:10.1002/roi.2970010305

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1993

数据来源: WILEY

摘要:

AbstractThe time of onset of accelerated tumor‐clonogen repopulation produced by radiotherapy is an important, but unresolved question. The suggestion by Withers et al. [Acta Oncol 27:131–146, 1988] and colleagues [Maciejewski and Majewski: Radiother Oncol 21:163–170, 1991]that onset is delayed has been questioned due to the variety of data sources and the methodology used to reach this conclusion. We describe an analysis of a single clinical data set, which allows a more credible estimate of the time of onset of accelerated repopulation. We analyze a recent report of tumor control of T2and T3laryngeal cancer as a function of dose and overall time. By virtue of their broad dynamic range, these results allow an estimate to be made of the time of onset of accelerated repopulation based on a single self‐consistent data set. The analyses suggest that rapid proliferation in these tumors is delayed by an estimated 32 days (95% confidence limits of 21–36 days). For these laryngeal tumors, and within the framework of the linear‐quadratic model, the hypothesis that accelerated repopulation begins at the start of radiotherapy can be rejected in favor of the suggestion that accelerated repopulation begins after 3–5 weeks. This conclusion, if generally true, would have significant ramifications for the design of optimized radiotherapeutic protocols. © 1993 W

ISSN:1065-7541    

DOI:10.1002/roi.2970010306

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1993

数据来源: WILEY

摘要:

AbstractIn conformation radiotherapy a target is irradiated uniformly, whereas surrounding organs receive non‐uniform radiation. Clinical data concerning complications with conventional radiation are not applicable there without appropriate compensation. A solution was proposed by Lyman [Int J Radiat Oncol Biol Phys 13:103–109, 1987 and 17:433–436, 1989; Radiat Res Suppl 8:13–19, 1985] using dose‐volume histograms. It reduces a given histogram to a single step which corresponds to the equivalent complication probability. It converts non‐uniform radiation into a unique dose to the whole organ which has the equivalent complication probability. This method was applied to actual patients treated by pion conformation technique at Paul Scherrer Institute (PSI). Of 90 pelvic tumors, 16 developed grade III‐TV bladder injury and 7 developed grade III‐IV rectal injury. The 90 cases were divided into roughly equal groups according to the equivalent doses to the entire bladder and rectum. Observed complication rates and the equivalent doses to the full organs in these groups could be represented by a sigmoid dose‐effect relation. When the relative biological effectiveness (RBE) is assumed to be 2.1 for bladder injury, the observed complication rates of the bladder fit best to the theoretical curve. When the RBE value is 2.3, the rates of rectal injury fit best. These values are close to the conversion factor of 2.0 used in clinical practice. This agreement suggests the feasibility of the method. © 19

ISSN:1065-7541    

DOI:10.1002/roi.2970010307

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1993

数据来源: WILEY

摘要:

AbstractThere has recently been a resurgence of interest in iodine‐125 (I‐125) prostate implantation for early stage carcinoma due to the introduction of transrectal ultrasonography (TRUS) or computerized‐tomographic (CT)‐based transperineal techniques. The present study details initial tumor response and morbidity of CT‐based transperineal prostate implantation. Forty‐two patients with clinical stage T1 or T2 prostatic carcinoma had CT‐planned transperineal I‐125 implantation of the prostate and have been followed for 6–47 months (median: 19 months). Thirty‐eight patients had an elevated PSA before implantation (>4.0 ng/ml). A total of 35–73 mCi I‐125 was implanted (median: 48 mCi). At 1 year after implantation, 84% of 29 palpable tumors were no longer palpable. Of 38 patients with an elevated prostate specific antigen (PSA) prior to implantation, 98% returned to normal within 12 months of treatment. In 74% of patients, the PSA value fell to below 1.0 ng/ml within 12 months of implantation. Of 25 patients who were sexually potent prior to implantation, 80% remained potent at 3 years. Four patients developed radiation‐induced rectal ulcerations 9–19 months following implantation. Of those four patients, one has healed spontaneously, two are improving, and one was diagnosed only 1 month prior to this report. Initial tumor response to I‐125 implantation is comparable to that achieved with external beam irradiation, with acceptable morbidity and high preservation of sexual potency. With adjustments in technique, morbidity is expected to be lower in the f

ISSN:1065-7541    

DOI:10.1002/roi.2970010308

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1993

数据来源: WILEY

ISSN:1065-7541    

DOI:10.1002/roi.2970010301

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1993

数据来源: WILEY