| 1. |
- Bansch, Peter, et al.
(author)
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Effect of charge on microvascular permeability in early experimental sepsis in the rat.
- 2011
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In: Microvascular Research. - : Elsevier BV. - 1095-9319 .- 0026-2862. ; 82, s. 339-345
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Journal article (peer-reviewed)abstract
- A key feature of sepsis is hypovolemia due to increased microvascular permeability. It has been suggested that the negative charge of albumin and of the endothelial glycocalyx is important for maintenance of the normally low permeability for albumin. Here we tested the hypothesis that charge effects contribute to the increased permeability in sepsis. Transcapillary escape rate (TER) and initial distribution volume for (125)I-labeled bovine serum albumin (BSA, isoelectric point pH 4.6) and for (131)I-labeled charge modified BSA (cBSA, average isoelectric point, pH 7.1) was measured 3h after sepsis was induced by cecal ligation and incision (CLI) (n=11) and in control animals (n=12). The importance of charge for permeability in sepsis was estimated by comparing the ratio between TER for cBSA and TER for BSA during control conditions to that after CLI. Plasma concentration of the glycocalyx component glycosaminoglycans (GAGs) was measured in separate control and CLI animals. The initial distribution volume for BSA and cBSA in control animals was 38±3ml/kg and 47±4mL/kg and decreased by 17% and 19%, respectively, following CLI. TER for BSA increased from 16.7±4.1% in the controls to 20.1±1.9% following CLI. Corresponding values for cBSA were 26.7±5.6% and 29.8±3.5%, respectively. The ratio between TER for cBSA and TER for BSA was 1.62±0.1 in the control group and 1.49±0.1 following CLI (p<0.05). Plasma GAG concentrations were higher in CLI animals than in the control group. We conclude that CLI induce hypovolemia secondary to increased microvascular permeability. Negative charge contributes to the normally low permeability of albumin and the importance of charge is decreased in early experimental sepsis. The observed charge effects are associated with CLI-induced breakdown of the glycocalyx.
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| 2. |
- Elgström, Erika, et al.
(author)
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Change in Cell Death Markers During (177)Lu-mAb Radioimmunotherapy-Induced Rejection of Syngeneic Rat Colon Carcinoma.
- 2014
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In: Cancer Biotherapy & Radiopharmaceuticals. - : Mary Ann Liebert Inc. - 1557-8852 .- 1084-9785. ; 29:4, s. 143-152
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Journal article (peer-reviewed)abstract
- Abstract Purpose: To monitor cell death in tumors during the rejection process after treatment with an antibody radiolabeled with a β-emitter. Methods: Tumors during rejection after treatment with (177)Lu-labeled antibody BR96 and after administration of unlabeled BR96 were compared with untreated tumors from the same immunocompetent syngeneic rat tumor model. Cell death was monitored with the terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay and immunohistochemical staining of activated caspase-3 and γH2AX. These data were evaluated together with histopathological morphology, BR96-binding antigen expression, and (177)Lu radioactivity distribution imaged by digital autoradiography. Results: The untreated tumors showed staining for all the markers, mainly in and around the necrotic areas. One to 2 days p.i. large areas were stained with anti-γH2AX, followed by a slight decrease. Staining of activated caspase-3 was intense and extensive 1-2 days p.i., while found in and around necrotic areas 3-8 days p.i. TUNEL staining was similar to activated caspase-3 staining 1-2 days p.i. but more extensive than activated caspase-3 staining 3-4 days p.i. Digital autoradiography revealed activity concentration in granulation tissue from 1 day p.i. Conclusion: Following radioimmunotherapy in an immunocompetent syngeneic colon carcinoma model, tumor cells did not only die through caspase-3-dependent apoptosis, but also by other mechanisms.
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| 3. |
- Elgström, Erika, et al.
(author)
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Pattern of antigen expression in metastases after radioimmunotherapy of a syngeneic rat colon carcinoma utilizing the BR96 antibody.
- 2012
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In: Experimental hematology & oncology. - : Springer Science and Business Media LLC. - 2162-3619. ; 1:1
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Journal article (peer-reviewed)abstract
- Abstract ABSTRACT: BACKGROUND: Repeated administration of antibody-based therapies such as radioimmunotherapy depends on preserved antigen expression in tumor lesions. The purpose of this study was to evaluate whether the antigen expression in metastases observed after radioimmunotherapy differs from that of untreated primary tumors. FINDINGS: 30 of the 35 Brown Norway rats with syngeneic colon carcinoma treated with 400 MBq/kg 177Lu-DOTA-BR96 exhibited consistent complete response of the primary tumor. 13 animals developed metastases that were detected after treatment. The antigen expression was reduced in 17 of 23 metastases detected after radioimmunotherapy compared with untreated tumors. No tumors completely lacked positively stained tumor cells. CONCLUSIONS: Although it was not possible to demonstrate that the antigen reduction is triggered by the radioimmunotherapy this result stress the importance of considering the risk of reduced antigen expression in metastases after radioimmunotherapy prior to further targeted therapies.
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| 4. |
- Eriksson, Sophie, et al.
(author)
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Repeated Radioimmunotherapy with (177)Lu-DOTA-BR96 in a Syngeneic Rat Colon Carcinoma Model.
- 2012
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In: Cancer Biotherapy & Radiopharmaceuticals. - : Mary Ann Liebert Inc. - 1557-8852 .- 1084-9785. ; 27:2, s. 134-140
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Journal article (peer-reviewed)abstract
- Abstract Aim: Fractionation is generally used as a mean to improve radioimmunotherapy (RIT). Since RIT is considered suitable for small-volume disease, the aim of the current study was to investigate whether repeated administration of (177)Lu-labeled mAb BR96 was tolerated and could delay or prevent metastatic disease after complete remission of the tumor obtained by the first administration. Methods: Immunocompetent rats bearing a syngeneic colon carcinoma were first treated with 400 MBq/kg (177)Lu-DOTA-BR96, an activity resulting in complete response in 29 of 30 animals. On day 21, two groups of rats were given an additional activity of 150 or 350 MBq/kg resulting in total administered activities corresponding to 0.9 and 1.3 times the maximal tolerated dose. Results: The additional treatment resulted in tolerable myelotoxicity; however, the frequency of metastatic disease and survival were not affected. Immunohistochemistry demonstrated binding of the BR96 antibody to tissue sections of analyzed metastases. Conclusions: In our model, development of metastatic disease after treatment of the manifest tumor was not prevented by an additional treatment with the same radioimmunoconjugate. Therefore, the antibody should be labeled with a more suitable radionuclide for treatment of metastases. The repeated targeted therapy was well tolerated in aspects of myelotoxicity.
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| 5. |
- Eriksson, Sophie, et al.
(author)
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Sequential Radioimmunotherapy with (177)Lu- and (211)At-Labeled Monoclonal Antibody BR96 in a Syngeneic Rat Colon Carcinoma Model.
- 2014
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In: Cancer biotherapy & radiopharmaceuticals. - : Mary Ann Liebert Inc. - 1557-8852 .- 1084-9785. ; 29:6, s. 238-246
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Journal article (peer-reviewed)abstract
- Abstract Alpha-particle emitters, such as astatine-211 ((211)At), are generally considered suitable for the treatment of small cell clusters due to their short path length, while beta-particle emitters, for example, Lutetium-177 ((177)Lu), have a longer path length and are considered better for small, established tumors. A combination of such radionuclides may be successful in regimens of radioimmunotherapy. In this study, rats were treated by sequential administration of first a (177)Lu-labeled antibody, followed by a (211)At-labeled antibody 25 days later. Methods: Rats bearing solid colon carcinoma tumors were treated with 400MBq/kg body weight (177)Lu-BR96. After 25 days, three groups of animals were given either 5 or 10MBq/kg body weight of (211)At-BR96 simultaneously with or without a blocking agent reducing halogen uptake in normal tissues. Control animals were not given any (211)At-BR96. Myelotoxicity, body weight, tumor size, and development of metastases were monitored for 120 days. Results: Tumors were undetectable in 90% of the animals on day 25, independent of treatment. Additional treatment with (211)At-labeled antibodies did not reduce the proportion of animals developing metastases. The rats suffered from reversible myelotoxicity after treatment. Conclusions: Sequential administration of (177)Lu-BR96 and (211)At-BR96 resulted in tolerable toxicity providing halogen blocking but did not enhance the therapeutic effect.
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| 6. |
- Eriksson, Sophie, et al.
(author)
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Treatment with Unlabeled mAb BR96 After Radioimmunotherapy with (177)Lu-DOTA-BR96 in a Syngeneic Rat Colon Carcinoma Model.
- 2012
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In: Cancer Biotherapy & Radiopharmaceuticals. - : Mary Ann Liebert Inc. - 1557-8852 .- 1084-9785. ; 27:3, s. 175-182
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Journal article (peer-reviewed)abstract
- Metastatic disease after successful treatment of the primary tumor continues to be a therapeutic challenge. Enhancement of therapeutic effects by the administration of unlabeled monoclonal antibodies (mAbs) after radioimmunotherapy (RIT) may provide a means of preventing or delaying the development of metastatic disease. In the present study, Brown Norway rats with syngeneic grafted colon carcinomas were administered the minimal effective therapeutic dose of 400 MBq/kg lutetium-177 ((177)Lu)-DOTA-BR96. After 2 weeks, half of the animals were given 15 mg/kg unlabeled mAb BR96 as consolidation therapy. Treatment response and toxicity were monitored 100 days after the treatment with unlabeled BR96. The treatment with unlabeled mAb after RIT resulted in a complete response (CR) in 19 of 19 animals, while RIT alone resulted in a CR in 17 of 19 animals. The additional treatment did not affect the number of animals with metastatic disease or the time to clinical symptoms of metastases. RIT resulted in reversible myelotoxicity. The unlabeled mAb BR96 did not cause any additional toxicity, making it possible to repeat the consolidation therapy.
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| 7. |
- Garkavij, Michael, et al.
(author)
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Lu-177-[DOTA0,Tyr3] Octreotate Therapy in Patients With Disseminated Neuroendocrine Tumors: Analysis of Dosimetry With Impact on Future Therapeutic Strategy
- 2010
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In: Cancer. - : Wiley. - 1097-0142 .- 0008-543X. ; 116:4, s. 1084-1092
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Journal article (peer-reviewed)abstract
- BACKGROUND: Lu-177-(DOTAO,Tyr3) octreotate is a new treatment modality for disseminated neuroendocrine tumors. According to a consensus protocol, the calculated maximally tolerated absorbed dose to the kidney should not exceed 27 Gy. In commonly used dosimetry methods, planar imaging is used for determination of the residence time, whereas the kidney mass is determined from a computed tomography (CT) scan. METHODS: Three different quantification methods were used to evaluate the absorbed dose to the kidneys. The first method involved common planar activity imaging, and the absorbed dose was calculated using the medical internal radiation dose (MIRD) formalism, using CT scan-based kidney masses. For this method, 2 region of interest locations for the background correction were investigated. The second method also included single-photon emission computed tomography (SPECT) data, which were used to scale the amplitude of the time-activity curve obtained from planar images. The absorbed dose was calculated as in the planar method. The third method used quantitative SPECT images converted to absorbed dose rate images, where the median absorbed dose rate in the kidneys was calculated in a volume of interest defined over the renal cortex. RESULTS: For some patients, the results showed a large difference in calculated kidney-absorbed doses, depending on the dosimetry method. The 2 SPECT-based methods generally gave consistent values, although the calculations were based on different assumptions. Dosimetry using the baseline planar method gave higher absorbed doses in all patients. The values obtained from planar imaging with a background region of interest placed adjacent to the kidneys were more consistent with dosimetry also including SPECT. For the accumulated tumor absorbed dose, the first 2 of the 4 planned therapy cycles made the major contribution. CONCLUSIONS: The results suggested that patients evaluated according to the conventional planar-based dosimetry method may have been undertreated compared with the other methods. Hematology and creatinine did not indicate any restriction for a more aggressive approach, which would be especially useful in patients with more aggressive tumors where there is not time for more protracted therapy. Cancer 2010;116(4 suppl):1084-92. (C) 2010 American Cancer Society.
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| 8. |
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| 9. |
- Kjölhede, Henrik, et al.
(author)
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Combined (18) F-fluorocholine and (18) F-fluoride positron emission tomography/computed tomography imaging for staging of high-risk prostate cancer.
- 2012
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In: BJU International. - 1464-4096. ; 110:10, s. 1501-1506
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Journal article (peer-reviewed)abstract
- Study Type - Diagnosis (cohort) Level of Evidence 2a What's known on the subject? and What does the study add? Positron emission tomography/computed tomography (PET/CT) with choline and fluoride for the detection of metastases in patients with prostate cancer have each been evaluated, with mixed results. Choline PET/CT has been evaluated against pelvic lymphadenectomy, generally with a low sensitivity but a high specificity; however, the study populations have been heterogenous. Fluoride PET/CT has been evaluated against other imaging methods, such as bone scan, single photon emission CT and MRI, and has been shown to have high specificity as well as sensitivity for bone metastases, but there are no studies with biopsy verification. This is the first study that evaluates the clinical use of both choline and fluoride PET/CT on the same patients in a well-defined population of patients with high-risk prostate cancer. OBJECTIVE: • To investigate how often positron emission tomography/computed tomography (PET/CT) scans, with both (18) F-fluorocholine and (18) F-fluoride as markers, add clinically relevant information for patients with prostate cancer who have high-risk tumours and a normal or inconclusive planar bone scan. PATIENTS AND METHODS: • Patients with prostate cancer with prostate specific antigen (PSA) levels between 20 and 99 ng/mL and/or Gleason score 8-10 tumours, planned for treatment with curative intent based on routine staging with a negative or inconclusive bone scan, were further investigated with a (18) F-fluorocholine and a (18) F-fluoride PET/CT. • None of the patients received hormonal therapy before the staging procedures were completed. RESULTS: • For 50 of the 90 included patients (56%) one or both PET/CT scans indicated metastases. • (18) F-fluorocholine PET/CT indicated lymph node metastases and/or bone metastases in 35 patients (39%). • (18) F-fluoride PET/CT was suggestive for bone metastases in 37 patients (41%). • In 18 patients (20%) the PET/CT scans indicated widespread metastases, leading to a change in therapy intent from curative to non-curative. • Of the patients with positive scans, 74% had Gleason score 8-10 tumours. Of the patients with Gleason score 8-10 tumours, 64% had positive scans. CONCLUSIONS: • PET/CT scans with (18) F-fluorocholine and (18) F-fluoride commonly detect metastases in patients with high-risk prostate cancer and a negative or inconclusive bone scan. • For 20% of the patients the results of the PET/CT scans changed the treatment plan.
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| 10. |
- Mårtensson, Linda, et al.
(author)
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High-Dose Radioimmunotherapy Combined With Extracorporeal Depletion in a Syngeneic Rat Tumor Model
- 2010
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In: Cancer. - : Wiley. - 1097-0142 .- 0008-543X. ; 116:4, s. 1043-1052
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Journal article (peer-reviewed)abstract
- BACKGROUND: The aim of the current study was to investigate the possibility of increasing the maximal tolerated dose (MTD) of a tumor-selective radiolabeled antibody when radioimmunotherapy (RIT) is combined with extracorporeal depletion of radioimmunoconjugates from the circulation. Furthermore, the authors evaluated whether this increase in dose improved the therapeutic effect on solid manifest tumors in an immunocompetent animal model. METHODS: Rats were injected with high activities/body weight of lutetium (Lu-177)- or yttrium (Y-90)-labeled antibody conjugates (monoclonal antibody tetraazacyclododecanetetraacetic acid-biotin) and subjected to removal of the conjugate from the circulation by extracorporeal affinity adsorption treatment 24 hours postinjection. Myelotoxicity was assessed by analysis of blood parameters for 12 weeks. The effect of increased doses in combination with extracorporeal affinity adsorption treatment was evaluated with respect to myelotoxicity and therapeutic effect in a syngeneic rat colon cancer model. RESULTS: The MTD of Lu-177- or Y-90-labeled immunoconjugates could be increased 2.0x or 1.5x, respectively, when RIT was combined with extracorporeal affinity adsorption treatment. All animals treated with Lu-177- or Y-90-labeled antibodies showed persistent complete response of manifest tumors (approximately 10 x 15 mm) within 16 days postinjection. However, several animals showed disseminated disease 1.5 to 3 months postinjection. CONCLUSIONS: Extracorporeal affinity adsorption treatment is a method that safely and efficiently reduces myelotoxicity associated with RIT. Extracorporeal affinity adsorption treatment allows increased administered activity without increased toxicity, with the aim of increasing the absorbed dose to the tumor. However, because tumor/normal tissue radiosensitivity ratios are more favorable in rodents, it is not possible to draw any conclusions concerning the therapeutic efficacy of increased administered activity in combination with extracorporeal affinity adsorption treatment in this study. Targeted RIT with beta-emitting radionuclides seems not to be effective in microscopic disease, because metastases developed at sites without previously known disease. (C) 2010 American Cancer Society.
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