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- Dimberg, J, et al.
(författare)
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Decreased levels of precursor transforming growth factor beta(1) in human colorectal cancer
- 2001
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Ingår i: International Journal of Molecular Medicine. - 1107-3756 .- 1791-244X. ; 7:6, s. 597-601
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Tidskriftsartikel (refereegranskat)abstract
- Transforming growth factor (TGF) beta (1) is a growth factor with wide-ranging effects on proliferation, differentiation, immunosuppression, apoptosis and matrix remodelling. TGF beta (1) seems to have an antitumorigenic role in the gastrointestinal tract but may also be associated with the development of colorectal cancer. Initially, TGF beta (1) is produced in a latent (precursor) form in epithelial cells and then is activated by a not clearly understood multistep process. In this study, we analysed precursor TGF beta (1) protein expression (n=40) and TGF beta (1) gene expression (n=49) in human colorectal adenocarcinomas and 49 normal adjacent tissue. Out of these 49 normal tissues 40 were matched. Western blot analysis revealed that the precursor TGF beta (1) protein levels were generally lower in colorectal cancerous tissue compared to adjacent noncancerous tissue (P <0.001). Furthermore, with real-time PCR our results cannot reflect a statistically significant difference in TGF beta (1) gene expression between the tumour tissue and normal tissue. These finds indicate that it is likely that there are mechanisms which control precursor TGF beta (1) protein expression by factor(s) at the level of pre-translation of the TGF beta (1) transcript and/or at the level of post-translation of the TGF beta (1) protein in the tumours. This process may be related to carcinogenesis and poses the question whether the suppression of the precursor TGF beta (1) is an early event, in vivo, in the human colorectal adenoma-carcinoma sequence.
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| 7. |
- Dimberg, Jan, et al.
(författare)
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Enhanced expression of cyclooxygenase-2 and nuclear beta-catenin are related to mutations in the APC gene in human colorectal cancer
- 2001
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Ingår i: Anticancer Research. - 0250-7005 .- 1791-7530. ; 21:2A, s. 911-915
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Tidskriftsartikel (refereegranskat)abstract
- Mutational inactivation of the human tumour suppressor gene adenomatous polyposis coli (APC) results in constitutive activation of beta -catenin/T cell factor-4 (Tcf-4) mediated transcription of target genes. Up-regulation of cyclooxygenase-2 (COX-2) protein is frequently found in human colorectal cancer (CRC). We analysed 38 CRC for mutations in APC and beta -catenin and found an association between APC mutations and elevated COX-2 levels. Furthermore, APC mutations were predominantly observed in tumour tissues from the rectum compared to tumours of colonic origin. Western blot analysis revealed that nuclear beta -catenin levels were generally higher in tumours with APC mutations compared to tumours with wild type APC. However, there was also a higher level of nuclear beta -catenin in tumour compared to normal tissue, hut nuclear Tcf-4 protein was constitutively expressed in tumour and normal tissue and showed no differences. An identified putative Tcf-4 binding element in the COX-2 promoter may partly explain the enhanced level of COX-2 and support the idea that COX-2 may be a downstream target of the APC/beta -catenin/Tcf-4 pathway.
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| 10. |
- Bolmsjo, M., et al.
(författare)
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Experimental set-up for studies of microwave-induced hyperthermia in rats
- 1982
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Ingår i: Physics in Medicine and Biology. - : IOP Publishing. - 0031-9155 .- 1361-6560. ; 27:3, s. 397-406
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Tidskriftsartikel (refereegranskat)abstract
- A low-cost microprocessor-based temperature controller for hyperthermia experiments on rats is described. The system directs a microwave generator, used for heating, by feedback power regulating signals in accordance with the temperature in the animal. The microwave power is pulsed for short on-and-off periods and the temperature recordings are carried out during the off periods. More than 300 hyperthermia runs have been carried out on rats using this fully automated unit. The controller can direct the hyperthermia to the predetermined level with a deviation of +or-0.1 degrees C for systemic hyperthermia. For local hyperthermia in the liver, individual recorded mean temperatures were up to -0.5 degrees C from the preset temperature.
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| 11. |
- Bolmsjö, M., et al.
(författare)
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Measurement of blood flow in rat liver with Xenon-133.
- 1983
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Ingår i: International journal of microcirculation, clinical and experimental / sponsored by the European Society for Microcirculation. - 0167-6865. ; 2:1, s. 27-37
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Tidskriftsartikel (refereegranskat)abstract
- The blood flow in rat liver was measured with Xe-133. Three techniques for administering the activity to the liver were employed: injection via the portal vein, via the hepatic artery, and directly into the liver parenchyma. Use of intraparenchymal injection of Xe-133 gave 60% higher flow values than by portal or arterial injection techniques. Mean flow index (k1) was for portal injection 0.52, for arterial injection 0.51 and for intraparenchymal injection 0.80. These variations may be explained by the microcirculatory anatomy of the rat liver. The data presented have a high degree of variance between repeated experiments on the same animal. During an experimental procedure, only larger changes in the liver blood flow pattern can be detected with sufficient accuracy. For this purpose, the method is applicable since repeated and regional studies on the same organ can easily be performed.
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| 13. |
- Hugander, A., et al.
(författare)
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Liver blood flow studies during local hyperthermia. An experimental study in rats
- 1983
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Ingår i: Clinical Oncology. - 0305-7399. ; 9:4, s. 303-310
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Tidskriftsartikel (refereegranskat)abstract
- Regional blood flow in rat liver and in inoculated liver tumors was studied before, during and after local hyperthermia treatment at 42.0°C for one hour. Hyperthermia was induced by microwave irradiation of the central liver lobe. The method used for blood flow studies was the clearance of Xenon-133 following portal and intraparenchymal injection. The wash-out curves were analyzed by using a bi-exponential approach where k1 and k2 represented the individual curve slope of the two components. The fast component, k1, was considered to denote the relative liver blood flow. There was no difference in blood flow (k1) between tumor and normal parenchyma before heating. During local hyperthermia of the liver lobe an overall statistically significant decrease in relative blood flow occurred. In normal liver parenchyma a statistically significant increase in blood flow occurred within 30 min after concluded hyperthermia with a return to prehyperthermic values. Intratumoral blood flow did not increase in the posthyperthermic period. The decrease in relative blood flow in the liver parenchyma during hyperthermia may be one explanation for liver sensitivity to hyperthermia treatment. Local hyperthermia may impair the tumor capillary network with a decreased blood flow and alteration in the intratumoral environment as a result.
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| 14. |
- Hugander, A., et al.
(författare)
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Total body hyperthermia induced by a computerized microwave technique : studies in normal rats and in rats with liver tumors.
- 1983
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Ingår i: Anticancer research. - 0250-7005. ; 3:3, s. 161-165
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Tidskriftsartikel (refereegranskat)abstract
- A computerized system for inducing total body hyperthermia by microwave irradiation was tested in rats. The tolerance to hyperthermia at different temperatures and fractions was studied as well as its effect on the growth of transplanted adenocarcinomas in the liver. Survival results indicated that 41.5 degrees C was maximum tolerated temperature both after single and repeated one hour exposures. Besides the high mortality with a greater temperature (42 degrees C) there was a significant rise in S-aspartate-amino-transferase (S-ASAT) and S-beta-hexosaminidase (beta-nagas) indicating damage of normal cells. No significant reduction of tumor volume could be registered after treatment with total body hyperthermia (41.5 degrees C) for one hour three times during a 24 hour period.
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