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At least 1,315 records · Page 73Linked to original sources
PubMed2003

Inhibition of neointimal proliferation with 188Re-labeled self-expanding nitinol stent in a sheep model.

PURPOSE: To evaluate a self-expanding rhenium 188 (188Re) radiochemically labeled radioactive stent in sheep. MATERIALS AND METHODS: A self-expanding nitinol stent (30 mm in length, 8 mm in diameter) coated with a functionalized polymer layer was radiolabeled with 188Re. Fifty prostheses, 25 of which were radioactive (mean radioactivity, 20 MBq +/- 3.8 [SD]) and 25 of which were nonradioactive, were implanted into the external iliac arteries of 25 sheep. Stent patency was assessed with angiography. Neointimal formation was assessed with intravascular ultrasonography and histologic examination 1 month (in all sheep) and 3 months (in 12 sheep) after implantation. The results were analyzed by using repeated-measures analysis of variance with two repeated factors and paired t tests for comparison at each measuring point. RESULTS: All stents were placed successfully. Data in one animal had to be excluded from the study. After 3 months, a mean neointimal area reduction of 70 mm2 +/- 55 (SD) was observed inside the radioactive stents, and a mean lumen reduction of 126 mm2 +/- 39 was observed inside the nonradioactive control stents (P =.022). An edge effect was observed in the radioactive stents in that they showed an amount of neointimal formation at the edges that was similar to that seen in control stents. This neointimal formation accounted for the maximum lumen loss in the vascular segment with the stent. CONCLUSION: As compared with a nonradioactive stent, a beta particle-emitting stent, through endovascular irradiation, significantly inhibits neointimal formation inside the stent but not at the stent edges.

Alloys↗
PubMed2007

[177Lu]pertuzumab: experimental therapy of HER-2-expressing xenografts.

Pertuzumab (Omnitarg) is a novel antibody against HER-2, domain II. HER-2 is a tyrosine kinase receptor that is overexpressed in several carcinomas, especially breast cancer. Pertuzumab, labeled with the low-energy beta emitter (177)Lu, might be a candidate for targeted radiotherapy of disseminated HER-2-positive micrometastases. The radiolabeled antibody [(177)Lu]pertuzumab showed favorable targeting properties in BALB/c (nu/nu) mice with HER-2-overexpressing xenografts. The absorbed dose in tumors was more than five times higher than the absorbed dose in blood and more than seven times the absorbed dose in any other normal organ. Experimental therapy showed that [(177)Lu]pertuzumab delayed tumor progression compared with controls (no treatment, P < 0.0001; nonlabeled pertuzumab antibody, P < 0.0001; and (177)Lu-labeled irrelevant antibody, P < 0.01). No adverse side effects of the treatment could be detected. Thus, the experimental results support the planning of clinical studies applying [(177)Lu]pertuzumab for therapy.

Animals↗
PubMed2006

Non-small-cell lung cancers with kinase domain mutations in the epidermal growth factor receptor are sensitive to ionizing radiation.

Non-small cell lung cancers (NSCLCs) bearing mutations in the tyrosine kinase domain (TKD) of the epidermal growth factor receptor (EGFR) often exhibit dramatic sensitivity to the EGFR tyrosine kinase inhibitors gefitinib and erlotinib. Ionizing radiation (IR) is frequently used in the treatment of NSCLC, but little is known how lung tumor-acquired EGFR mutations affect responses to IR. Because this is of great clinical importance, we investigated and found that clonogenic survival of mutant EGFR NSCLCs in response to IR was reduced 500- to 1,000-fold compared with wild-type (WT) EGFR NSCLCs. Exogenous expression of either the L858R point mutant or the DeltaE746-E750 deletion mutant form of EGFR in immortalized human bronchial epithelial cells, p53 WT NSCLC (A549), or p53-null NSCLC (NCI-H1299) resulted in dramatically increased sensitivity to IR. We show that the majority of mutant EGFR NSCLCs, including those that contain the secondary gefitinib resistance T790M mutation, exhibit characteristics consistent with a radiosensitive phenotype, which include delayed DNA repair kinetics, defective IR-induced arrest in DNA synthesis or mitosis, and pronounced increases in apoptosis or micronuclei. Thus, understanding how activating mutations in the TKD domain of EGFR contribute to radiosensitivity should provide new insight into effective treatment of NSCLC with radiotherapy and perhaps avoid emergence of single agent drug resistance.

Apoptosis↗
PubMed1999

Cutaneous T cell lymphoma: update of treatment.

The state-of-the art therapy of cutaneous T cell lymphoma (CTCL) is reviewed. Commonly used treatments for early-stage (patch/plaque) mycosis fungoides (MF) include topical corticosteroids, mechlorethamine, carmustine, ultraviolet light B and PUVA. Total skin electron beam (TSEB) therapy is indicated for widespread infiltrated plaque and tumor stage disease. Low-dose methotrexate is often useful for resistant patch/plaque MF and erythrodermic CTCL. Interferon alpha (IFN-alpha) is indicated for methotrexate failures and recurrent tumors following TSEB therapy. Photopheresis may be helpful for early-stage erythrodermic CTCL but is very costly. Retinoids may be of value for early and moderately advanced CTCL particularly in combination with other agents such as IFN-alpha and PUVA. Systemic disease usually requires combination chemotherapy such as that used for non-Hodgkin's lymphoma; however, responses are usually short lived.

Administration, Topical↗
PubMed1998

[Comparative study of beta irradiation (106Ru/106Rh) and gamma irradiation (125I) on the rabbit eye].

We compared beta irradiation (106Ru/106Rh) to gamma irradiation (125I) on the normal rabbit eye, using ophthalmic plaques to deliver doses similar to those recommended in man for choroidal melanoma treatment. A detailed dosimetry was performed and the animals were followed up by clinical and histological examinations during 1 year. The mean total doses were either comparable, or larger with iodine-125, but the globes treated with ruthenium-106 exhibited more damaging effects: total destruction of the chorioretina on the plaque site, abnormalities of the retinal vessels and of the close nerve fiber layers, cavernous atrophy of the optic nerve. In the eyes treated with iodine-125, only the external retinal layers were destroyed.

Animals↗
PubMedDate not supplied

Irradiation for inhibition of endothelial cell growth in vitro.

The clinical effect of ionising radiation on ocular neovascularisations is controversial, not only because of the variety of treatment modalities. The aim of our study was to investigate an experimental model which allows to evaluate radiation parameters and to study the mechanism of the inhibitory effect on neoangiogenesis. In vitro experiments were performed using human umbilical vein endothelial cells and human corneal keratocytes. The cells were irradiated with different doses of photon beam radiation and counted daily after treatment. Cell cultures confirmed the efficiency of irradiation in inhibiting proliferation of vascular endothelial cells. Radiosensitivity was shown to be higher in vascular endothelial cells than in corneal stromal keratocytes. This might be helpful in investigating therapy parameters for treating ocular neovascularisations, as well as underlying mechanisms.

Beta Particles↗
PubMed2005

Beta-ray brachytherapy of retinoblastoma: feasibility of a new small-sized ruthenium-106 plaque.

UNLABELLED: A non-comparative case observation study estimated the feasibility of brachytherapy for retinoblastoma with a newly designed ruthenium-106 plaque (label: CXS) with an 8-mm diameter of the irradiation zone. METHODS: The new CXS plaque was used between 2001 and 2003 for brachytherapy of 13 retinoblastomas. Indications were recurrences after preceding local treatment or endophytic retinoblastoma with an impending vitreous tumour cell seeding. The prescribed radiation dose at the apex was 88 Gy (NIST-calibrated dosimetry). RESULTS: The mean age at brachytherapy was 1.2 years (standard deviation, SD: 1.1 years), and the mean follow-up was 1.7 years (SD: 0.6 years). The treated tumours had a mean diameter of 2.3 mm (SD: 0.7 mm) and a mean height of 1.5 mm (SD: 0.6 mm) with a mean distance to the optic disc of 9.9 mm (SD: 2.2 mm). The mean duration of irradiation was 29.3 h (SD: 9.9 h) with a mean dose at the sclera of 213 Gy (SD: 80 Gy). Surgery was uneventful in all cases. Complete regression developed after 3.1 months (SD: 2.8 months) in all cases without a recurrence or a progression of the vitreous tumour cell seeding. The eyes developed no further side-effects besides a temporary circumscribed intra-ocular haemorrhage that emerged from the regressive tumour remnants. CONCLUSION: Brachytherapy with the CXS plaque seems to be a safe and reliable treatment option for small-sized retinoblastoma when laser or cryocoagulation failed to control the tumour growth or for small retinoblastoma with an incipient local tumour cell seeding on the tumour surface.

Beta Particles↗
PubMed1994

Two distinct types of reticular cells in the pig sheathed artery.

The morphology of reticular cells of the sheathed arteries, in the red pulp of pig spleen, was studied by using transmission electron microscopy; and their histochemical reactivity with periodic acid-thiocarbohydrazide-silver proteinate (PA-TCH-SP). The phagocytic ability was evaluated by injecting colloidal carbon into the splenic artery. Reticular cells of the sheathed arteries were classified as type I and type II cells. Type I cells have a nucleus with scanty chromatin, and the cytoplasm reacts positively to PA-TCH-SP. The PA-TCH-SP-positive granules are considered to be subunits of beta-glycogen particles based on their morphological features. Type II cells have a nucleus with abundant chromatin and are not stained by PA-TCH-SP. Both types of reticular cells are connected with reticular fibers. Results of the colloidal carbon injection showed that type I reticular cells did not ingest carbon particles during the time frame of the experiment, whereas type II reticular cells are phagocytic and ingested carbon.

Animals↗
PubMed1991

Fractionated beta-irradiation of a conjunctival lymphangioma.

Fractionated beta-radiation was applied on a conjunctival lymphangioma, which had been known for several years. Histological diagnosis was established 3 years previously. Excision was not possible because the tumor had involved a considerable part of the conjunctiva. Using a strontium-90 applicator a total dose of 30 Gy was applied in 6 fractions with 5 Gy each. The initial tolerance was satisfactory. No radiogenic damage occurred, an involution of the tumor could be observed. During a follow-up time of nearly 2 years no further progression was noted. We consider the beta-radiation as an interesting therapeutic alternative for conjunctival lymphangiomas which are difficult to treat surgically due to their size.

Beta Particles↗