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Query: UMLS:C0027651 (tumor)
 685,946 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Lipopolysaccharide (LPS) was shown to induce tumoricidal activity in peritoneal macrophages. The optimal concentration was found to be 25 micrograms/mL. Approximately 20-h exposure to LPS was required before maximal tumor cell killing was attained. Optimal tumor killing was obtained with a ratio of tumor cell to macrophages of 1:40 with the macrophages in a confluent layer. Diphenylene iodonium (DPI) reduced the tumor cell killing in a dose dependent manner up to 1 microM. Under similar conditions DPI was shown to inhibit the superoxide production of macrophages and this supports the view that the production of oxygen radicals is important in the killing of tumor cells by macrophages and that the inhibitor DPI can be used to investigate their contribution to cytotoxicity.
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PMID:The use of diphenylene iodonium and its analogues to investigate the role of the NADPH oxidase in the tumoricidal activity of macrophages in vitro. 193 27

A mathematical model analysis is used to address the question of optimal scheduling of combined treatments consisting of biologically targeted radiotherapy (BTR), total body irradiation (TBI), and bone marrow rescue. Radiation effects on normal tissue are described using an extension of the LQ model. Tumor effects are described using a simple model that allows for radiation-induced sterilization and exponential proliferation of tumor cells, a proportion of which completely escapes the effects of targeted radiotherapy. The effect on a tumor cell population of a set of treatment schedules, composed partly of targeted radiotherapy and partly of fractionated external beam irradiation, are calculated. Treatment schedules are chosen to be biologically equivalent, for a "late responding" organ, to a fractionated TBI schedule of 7 fractions of 2 Gy. The tumor effects of the treatment schedules depend on the specificity of targeting, represented by the ratio of initial dose-rate for the tumor cells to that in the dose-limiting organ, and the heterogeneity of targeting, represented by the proportion of tumor cells that escape irradiation by targeted radiotherapy. The main mechanism determining optimal combinations is an overkill of effectively targeted tumor cells. Treatment regiments consisting of targeted radiotherapy alone fail, due to the unimpeded growth of those tumor cells that escape targeted irradiation. Optimal schedules almost invariably consist of elements of both BTR and TBI. Although it is recognized that the model is simplistic in a number of respects, these findings provide support for the clinical use of integrated BTR, TBI, and bone marrow rescue for the treatment of systemic malignant disease.
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PMID:Optimal scheduling of biologically targeted radiotherapy and total body irradiation with bone marrow rescue for the treatment of systemic malignant disease. 193 68

Bladder cancer accounts for approximately 3% of all malignancies. About 70% of bladder cancers are superficial tumors (Ta, Tis, T1), the remaining 30% are muscle-invasive (T2-4). Important prognostic factors include TNM-stage, histologic grade, multifocality, associated Tis, and residual tumor after TUR. Superficial cancers are managed by TUR and, if necessary, intravesical chemotherapy, and bladder preservation is possible. In case of T1G3-cancers, we favour TUR plus irradiation with a moderate dose instead of cystectomy. Even advanced bladder cancers may be treated by an organ sparing approach. TUR plus radiotherapy or radiochemotherapy offer comparable survival figures and local control rates as compared to radical cystectomy. The 5-year survival rates are 60-70% for T1-2, 40% for T3, and 15% for T4-tumors. About 70% of long-term survivors maintain a functioning bladder. Radiochemotherapy (RCT) with platin compounds is equally effective but less toxic as compared to multi-agent chemotherapy or intraarterial administrations. We do not recommend preoperative radiotherapy or RCT with planned cystectomy because of the definitive organ loss. Optimal treatment results are achieved by complete TUR prior to irradiation. Persistent or recurrent tumor after radiotherapy requires salvage cystectomy. Intravesical recurrences in the spared bladder have a good prognosis. Adjuvant chemotherapy of bladder cancer is not established. Neoadjuvant chemotherapy may result in 20-30% complete remissions, but these figures are lower than those after radiotherapy or radiochemotherapy. Nevertheless, adjuvant treatment protocols are necessary because of the fact that even sophisticated local treatment with increased local control has not yet improved the overall survival rates.
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PMID:[Radiotherapy in the interdisciplinary approach to the treatment of bladder carcinoma]. 194 42

A study of 28 adolescents aged 10-20 years admitted with ovarian tumors during a 5-year period revealed that 75% had malignant ovarian tumors, with germ cell tumors being most frequent. The high incidence of malignancy was due to our hospital being a referral centre. One case of mixed germ cell tumor (mainly choriocarcinoma) presented with precocious puberty, and one case of arrhenoblastoma showed signs of virilization. Tumor markers were found useful in diagnosing choriocarcinoma and endodermal sinus tumor. Amongst the malignant ovarian tumors, the best prognosis was noted with dysgerminomas. Tumors were found more frequently on the right side. Optimal surgery at initial laparotomy, followed by adjuvant chemotherapy or radiotherapy were found to offer the best change of cure.
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PMID:Ovarian tumors in the second decade of life. 195 33

Targeted radiotherapy consists of biologically selective irradiation of malignant cells by means of radionuclides attached to tumour-seeking molecules. A variety of clinical strategies for targeted radiotherapy may be used, for which different normal tissues will be critical. A large number of radionuclides exist, emitting nuclear particles with a range of path lengths from nanometres to millimetres. An important feature of normal-tissue radiobiology is the dose-rate effect, which is especially marked for late-responding tissues. Radiobiological calculations imply that tolerance dose for targeted radiotherapy using low-LET emitters will depend strongly on the effective half-life of the radionuclide, which will be affected by pharmacokinetics and may vary between patients. Some strategies designed to improve the therapeutic radio (e.g. accelerated clearance of radionuclide) may have modulating effects on the tolerance dose. Tumour response will be governed by the 'four Rs' (repair, repopulation, reoxygenation, redistribution) as well as by mechanisms peculiar to targeted radiotherapy. Analysis based on the extended linear quadratic model predicts that dose-rate effects will be of major importance for only a minority of tumours. Most of the radiation dose to tumour will usually be delivered over a time-scale of a few days. This might give insufficient time for tumour reoxygenation, making the use of hypoxic sensitizers appropriate. A special feature of targeted radiotherapy is the complex relationship between tumour curability and tumour size for different radionuclides. For long-range beta-emitters, microscopic tumours may be operationally resistant because of inefficient absorption of radionuclide disintegration energy in small volumes. Short-range emitters will be more efficient in sterilization of micrometastases but sterilization of larger tumours may require an unattainable degree of homogeneity of radionuclide distribution. Optimal use of targeted radiotherapy may require it to be combined with external-beam irradiation or chemotherapy. Experimental studies will be necessary to investigate those features of targeted radiotherapy which differ from external-beam irradiation. Future directions may include targeted radiotherapy of minimal numbers of tumour cells detected by use of molecular probes. Such applications call for use of short-range alpha-emitters and Auger emitters whose radiobiology will become increasingly important.
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PMID:The radiobiology of targeted radiotherapy. 197 28

Interleukin-3 (IL-3) is a hematopoietic growth factor that regulates the differentiation of multilineage and committed progenitor cells and the functions of some mature blood cells. The expression of human IL-3 appears to be restricted to stimulated T lymphocytes. We have investigated the kinetics and mechanisms involved in the induction of IL-3 expression in the human T lymphocytic tumor cell line Jurkat. We show that accumulation of IL-3 mRNA is controlled at both the transcriptional and posttranscriptional level. Transcription of the IL-3 gene in these cells appears to be constitutive but no IL-3 mRNA was detected in unstimulated cells, indicating that in resting cells IL-3 mRNA is highly unstable. Treatment with phytohemagglutinin (PHA) induced a small and transient increase in the IL-3 gene transcription rate and led to the production of detectable levels of IL-3 mRNA and protein. Optimal induction of IL-3 expression required a second stimulus. Costimulation of Jurkat cells with both phorbol myristate acetate and PHA caused both a transient increase in IL-3 gene transcription, which is dependent on new protein synthesis, and also a transient increase in mRNA stability.
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PMID:Human interleukin-3 mRNA accumulation is controlled at both the transcriptional and posttranscriptional level. 200 50

Relative operating characteristic (ROC) analysis was used to examine the clinical applicability of 3 breast carcinoma tumor markers, CA 15.3, carcinoembryonic antigen, and mucin-like carcinoma-associated antigen. Each tumor marker was quantitated in single serum samples collected from 100 normal blood donors, 60 patients with nonmalignant diseases, 33 women at high risk for breast carcinoma, 30 patients with malignancies other than breast carcinoma, and 158 breast carcinoma patients including 67 with no evidence of disease following surgery, 46 with a tumor burden less than 5 g, and 45 with a tumor burden greater than 5 g. These were used to construct models for early diagnosis among those at high risk for breast carcinoma, the influence of nonmalignant disease on early diagnosis, discrimination of breast carcinoma from other adenocarcinomas, detection of early recurrence, and assessment of change in tumor burden. For each model ROC data permitted the unbiased selection of the most appropriate critical values based on the interaction of sensitivity and specificity. ROC analysis indicated that in practice the assays were remarkably similar. While CA 15.3 generally performed best, there was significant variation among models. Optimal marker selection can thus depend on specific clinical application. In some cases ROC identified a combination of markers as superior to any single assay, but this was not statistically significant.
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PMID:Relative operating characteristic analysis and group modeling for tumor markers: comparison of CA 15.3, carcinoembryonic antigen, and mucin-like carcinoma-associated antigen in breast carcinoma. 200 74

From January 1, 1984 to April 30, 1990, 38 patients were surgically found to have an intraabdominal disease resembling epithelial ovarian cancer. This diagnosis was confirmed in 31 patients; the remaining 7 met the criteria of primary peritoneal papillary serous carcinoma. Five of these were diagnosed retrospectively and two during surgery. The mean age at diagnosis was 61.2 years. Tumor histology revealed papillary serous carcinoma in six and mixed (papillary serous and papillary clear cell carcinoma) in one patient. Optimal debulking was achieved in three of seven cases (42.8%). Cisplatin-based combination chemotherapy was administered to all in the study group. Complete response was obtained in four patients, with one surviving for 76 months. The median survival in these patients was 34.5 months (range 6-76 months). Currently, three patients with complete response are alive with clinically undetectable disease. CA-125 assays were available in three cases and blood levels corroborated the clinically determined status of the disease. Tumor steroid hormone receptor status was determined in one case and revealed low levels of estrogen and progesterone receptors. To the best of our knowledge, the usefulness of CA-125 in the diagnosis, management, follow-up, and determination of tumor steroid hormone receptor status, mixed papillary serous and clear cell subtype histological patterns for primary peritoneal papillary serous carcinoma are first described in this report. It seems that this neoplasm may be treated and followed up as in epithelial ovarian cancer, obtaining long-term survival; however, the biologic behavior and management problems of this relatively new entity deserve further clinical experience.
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PMID:Primary peritoneal papillary serous adenocarcinoma: clinical and management aspects. 201 45

The aromatase enzyme and its inhibition by R 76 713 were characterized in the JEG-3 choriocarcinoma cell line in culture and in JEG-3 tumors grown in nude mice. Optimal cell culture parameters and enzyme reaction conditions for the determination of aromatase activity were established. Under these conditions, in vitro JEG-3 aromatase was inhibited by R 76 713 with IC50-values of 7.6 +/- 0.5 nM and 2.7 +/- 1.1 nM using 500 nM of androstenedione and testosterone as substrate respectively. The Km-value of the aromatase enzyme with androstenedione as substrate was 62 +/- 19 nM; with testosterone as substrate, a value of 166 +/- 27 nM was found. In the presence of increasing concentrations of R 76 713, the Km-values increased while the Vmax remained unchanged. Using androstenedione and testosterone as substrate Lineweaver-Burk analysis of the data showed Ki-values for R 76 713 of 0.43 +/- 0.06 nM and 0.47 +/- 0.39 nM respectively. R 76 713 appeared to competitively inhibit the JEG-3 aromatase. Aromatase could easily be measured in homogenates of JEG-3 tumors grown in nude mice and showed Km-values similar to those found for JEG-3 cells in vitro. IC50-values for inhibition of tumor aromatase by R 76 713 were also similar to those found in cultured cells. Tumor aromatase measured ex vivo, 2 h after a single oral administration of R 76 713 was dose-dependently inhibited. An ED50-value of 0.05 mg/kg was calculated. The JEG-3 choriocarcinoma proved to be a useful aromatase model enabling the comparative study of aromatase inhibition in vitro and in vivo.
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PMID:Aromatase in the human choriocarcinoma JEG-3: inhibition by R 76 713 in cultured cells and in tumors grown in nude mice. 203 56

Optimal resection of pelvic tumor was facilitated by cystotomy in one patient with a benign and five patients with malignant adherent pelvic tumors. Four of the five patients with malignant tumors had recurrent or persistent carcinoma of the ovary. Blood loss and surgical duration were acceptable and there were no postoperative complications. Cystotomy is a relatively easy and safe procedure and is recommended when optimal resection of adherent pelvic tumor is attempted.
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PMID:Cystotomy--for facilitation of optimal resection of adherent pelvic tumors. 205 Mar 4


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