Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 21
Filtrar
1.
Clin Nucl Med ; 49(5): e206-e207, 2024 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-38389221

RESUMO

ABSTRACT: Gamma/delta T-cell lymphoma is a rare and aggressive subtype of primary cutaneous lymphoma. Clinical manifestations typically include the development of subcutaneous nodules and ulcerated plaques. Some forms present as panniculitis with hemophagocytic syndrome. Prognosis is bleak, with a 10% 5-year survival rate. In this report, we present the case of a 20-year-old man from French Polynesia, referred for 18 F-FDG PET/CT because of the progressive worsening of febrile cutaneous-mucosal infiltration on the face persisting for 1 month. PET examination guided a biopsy from the right deltoid muscle, and expert histological analysis confirmed a CD8 + not otherwise specified T-cell lymphoma, granzyme+ and TCR gamma/delta.


Assuntos
Linfoma Cutâneo de Células T , Linfoma de Células T , Paniculite , Neoplasias Cutâneas , Masculino , Humanos , Adulto Jovem , Adulto , Linfócitos T/patologia , Fluordesoxiglucose F18 , Tomografia por Emissão de Pósitrons combinada à Tomografia Computadorizada , Linfoma Cutâneo de Células T/diagnóstico por imagem , Linfoma de Células T/patologia , Neoplasias Cutâneas/diagnóstico por imagem , Neoplasias Cutâneas/patologia , Paniculite/patologia
2.
Cancers (Basel) ; 14(3)2022 Jan 27.
Artigo em Inglês | MEDLINE | ID: mdl-35158904

RESUMO

(1) Background: triple-negative breast cancer (TNBC) remains a clinical and therapeutic challenge primarily affecting young women with poor prognosis. TNBC is currently treated as a single entity but presents a very diverse profile in terms of prognosis and response to treatment. Positron emission tomography/computed tomography (PET/CT) with 18F-fluorodeoxyglucose ([18F]FDG) is gaining importance for the staging of breast cancers. TNBCs often show high [18F]FDG uptake and some studies have suggested a prognostic value for metabolic and volumetric parameters, but no study to our knowledge has examined textural features in TNBC. The objective of this study was to evaluate the association between metabolic, volumetric and textural parameters measured at the initial [18F]FDG PET/CT and disease-free survival (DFS) and overall survival (OS) in patients with nonmetastatic TBNC. (2) Methods: all consecutive nonmetastatic TNBC patients who underwent a [18F]FDG PET/CT examination upon diagnosis between 2012 and 2018 were retrospectively included. The metabolic and volumetric parameters (SUVmax, SUVmean, SUVpeak, MTV, and TLG) and the textural features (entropy, homogeneity, SRE, LRE, LGZE, and HGZE) of the primary tumor were collected. (3) Results: 111 patients were enrolled (median follow-up: 53.6 months). In the univariate analysis, high TLG, MTV and entropy values of the primary tumor were associated with lower DFS (p = 0.008, p = 0.006 and p = 0.025, respectively) and lower OS (p = 0.002, p = 0.001 and p = 0.046, respectively). The discriminating thresholds for two-year DFS were calculated as 7.5 for MTV, 55.8 for TLG and 2.6 for entropy. The discriminating thresholds for two-year OS were calculated as 9.3 for MTV, 57.4 for TLG and 2.67 for entropy. In the multivariate analysis, lymph node involvement in PET/CT was associated with lower DFS (p = 0.036), and the high MTV of the primary tumor was correlated with lower OS (p = 0.014). (4) Conclusions: textural features associated with metabolic and volumetric parameters of baseline [18F]FDG PET/CT have a prognostic value for identifying high-relapse-risk groups in early TNBC patients.

3.
J Clin Med ; 9(11)2020 Oct 27.
Artigo em Inglês | MEDLINE | ID: mdl-33120982

RESUMO

BACKGROUND: Pseudoxanthoma elasticum (PXE) is an inherited metabolic disease characterized by elastic fiber fragmentation and ectopic calcification. There is growing evidence that vascular calcification is associated with inflammatory status and is enhanced by inflammatory cytokines. Since PXE has never been considered as an inflammatory condition, no incidence of chronic inflammation leading to calcification in PXE has been reported and should be investigated. In atherosclerosis and aortic stenosis, positron emission tomography combined with computed tomographic (PET-CT) imaging has demonstrated a correlation between inflammation and calcification. The purpose of this study was to assess skin/artery inflammation and calcification in PXE patients. Methods: 18F-FluroDeoxyGlucose (18F-FDG) and 18F-Sodium Fluoride (18F-NaF) PET-CT, CT-imaging and Pulse wave velocity (PWV) were used to determine skin/vascular inflammation, tissue calcification, arterial calcium score (CS) and stiffness, respectively. In addition, inorganic pyrophosphate, high-sensitive C-reactive protein and cytokines plasma levels were monitored. RESULTS: In 23 PXE patients, assessment of inflammation revealed significant 18F-FDG uptake in diseased skin areas contrary to normal regions, and exclusively in the proximal aorta contrary to the popliteal arteries. There was no correlation between 18F-FDG uptake and PWV in the aortic wall. Assessment of calcification demonstrated significant 18F-NaF uptake in diseased skin regions and in the proximal aorta and femoral arteries. 18F-NaF wall uptake correlated with CS in the femoral arteries, and aortic wall PWV. Multivariate analysis indicated that aortic wall 18F-NaF uptake is associated with diastolic blood pressure. There was no significant correlation between 18F-FDG and 18F-NaF uptake in any of the artery walls. CONCLUSION: In the present cross-sectional study, inflammation and calcification were not correlated. PXE would appear to more closely resemble a chronic disease model of ectopic calcification than an inflammatory condition. To assess early ectopic calcification in PXE patients, 18F-NaF-PET-CT may be more relevant than CT imaging. It potentially constitutes a biomarker for disease-modifying anti-calcifying drug assessment in PXE.

4.
Front Bioeng Biotechnol ; 8: 602998, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33718332

RESUMO

Inhibition of the PI3K/Akt/mTOR signaling pathway represents a potential issue for the treatment of cancer, including glioblastoma. As such, rapamycin that inhibits the mechanistic target of rapamycin (mTOR), the downstream effector of this signaling pathway, is of great interest. However, clinical development of rapamycin has floundered due to the lack of a suitable formulation of delivery systems. In the present study, a novel method for the formulation of safe rapamycin nanocarriers is investigated. A phase inversion process was adapted to prepare lipid nanocapsules (LNCs) loaded with the lipophilic and temperature sensitive rapamycin. Rapamycin-loaded LNCs (LNC-rapa) are ~110 nm in diameter with a low polydispersity index (<0.05) and the zeta potential of about -5 mV. The encapsulation efficiency, determined by spectrophotometry conjugated with filtration/exclusion, was found to be about 69%, which represents 0.6 wt% of loading capacity. Western blot analysis showed that LNC-rapa do not act synergistically with X-ray beam radiation in U87MG glioblastoma model in vitro. Nevertheless, it demonstrated the selective inhibition of the phosphorylation of mTORC1 signaling pathway on Ser2448 at a concentration of 1 µM rapamycin in serum-free medium. Interestingly, cells cultivated in normoxia (21% O2) seem to be more sensitive to mTOR inhibition by rapamycin than those cultivated in hypoxia (0.4% O2). Finally, we also established that mTOR phosphorylation inhibition by LNC-rapa induced a negative feedback through the activation of Akt phosphorylation. This phenomenon was more noticeable after stabilization of HIF-1α in hypoxia.

5.
Front Pharmacol ; 10: 772, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31354487

RESUMO

Glioblastoma is the most common malignant adult brain tumor and has a very poor patient prognosis. The mean survival for highly proliferative glioblastoma is only 10 to 14 months despite an aggressive current therapeutic approach known as Stupp's protocol, which consists of debulking surgery followed by radiotherapy and chemotherapy. Despite several clinical trials using anti-angiogenic targeted therapies, glioblastoma medical care remains without major progress in the last decade. Recent progress in nuclear medicine, has been mainly driven by advances in biotechnologies such as radioimmunotherapy, radiopeptide therapy, and radionanoparticles, and these bring a new promising arsenal for glioblastoma therapy. For therapeutic purposes, nuclear medicine practitioners classically use ß- particle emitters like 131I, 90Y, 186/188Re, or 177Lu. In the glioblastoma field, these radioisotopes are coupled with nanoparticles, monoclonal antibodies, or peptides. These radiopharmaceutical compounds have resulted in a stabilization and/or improvement of the neurological status with only transient side effects. In nuclear medicine, the glioblastoma-localized and targeted internal radiotherapy proof-of-concept stage has been successfully demonstrated using ß- emitting isotopes. Similarly, α particle emitters like 213Bi, 211At, or 225Ac appear to be an innovative and interesting alternative. Indeed, α particles deliver a high proportion of their energy inside or at close proximity to the targeted cells (within a few micrometers from the emission point versus several millimeters for ß- particles). This physical property is based on particle-matter interaction differences and results in α particles being highly efficient in killing tumor cells with minimal irradiation of healthy tissues and permits targeting of isolated tumor cells. The first clinical trials confirmed this idea and showed good therapeutic efficacy and less side effects, thus opening a new and promising era for glioblastoma medical care using α therapy. The objective of this literature review is focused on the developing field of nuclear medicine and aims to describe the various parameters such as targets, vectors, isotopes, or injection route (systemic and local) in relation to the clinical and preclinical results in glioblastoma pathology.

6.
Front Med (Lausanne) ; 6: 124, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31214593

RESUMO

Monoclonal antibody (mAb)-based therapies have experienced considerable growth in cancer management. When labeled with radionuclides, mAbs also represent promising probes for imaging or theranostic approaches. Initially, mAbs have been radiolabeled with single-photon emitters, such as 131I, 99mTc, or 111In, for diagnostic purposes or to improve radioimmunotherapy (RIT) using dosimetry estimations. Today, more accurate imaging is achieved using positron- emission tomography (PET). Thanks to the important technical advances in the production of PET emitters and their related radiolabeling methods, the last decade has witnessed the development of a broad range of new probes for specific PET imaging. Immuno-PET, which combines the high sensitivity and resolution of a PET camera with the specificity of a monoclonal antibody, is fully in line with this approach. As RIT, immuno-PET can be performed using directly radiolabeled mAbs or using pretargeting to improve imaging contrast. Pretargeted immuno-PET has been developed against different antigens, and promising results have been reported in tumor expressing carcinoembryonic antigen (CEA; CEACAM5) using a bispecific mAb (BsmAb) and a radiolabeled peptide. Medullary thyroid carcinoma (MTC) is an uncommon thyroid cancer subtype which accounts for <10% of all thyroid neoplasms. Characterized by an intense expression of CEA, MTC represents a relevant tumor model for immuno-PET. High sensitivity of pretargeted immunoscintigraphy using murine or chimeric anti-CEA BsMAb and pretargeted haptens-peptides labeled with 111In or 131I were reported in metastatic MTC patients 20 years ago. Recently, an innovative clinical study reported high tumor uptake and contrast using pretargeted anti-CEA immuno-PET in relapsed MTC patients. This review focuses on MTC as an example, but the same pretargeting technique has been applied with success for clinical PET imaging of other CEA-expressing tumors and other pretargeting systems. In particular, those exploiting bioorthogonal chemistry also appear interesting in preclinical animal models, suggesting the high potential of pretargeting for diagnostic and theranostic applications.

8.
Int J Nanomedicine ; 12: 8159-8170, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-29184405

RESUMO

Lipid nanocapsules (LNCs) are potential drug carriers for pulmonary delivery since they can be nebulized without any structural or functional changes, and the aerosols produced are highly compatible with pulmonary drug delivery in human beings. The alveolar surface tension, in vitro cytotoxicity, biodistribution and pulmonary toxicity in rats of a single endotracheal spray of LNCs or paclitaxel-loaded LNCs were studied. In vitro cytotoxicity of LNCs after a spray remained unchanged. Biodistribution study showed a homogeneous repartition in the lungs in rats with an improvement in lung retention of the radiolabeled tracer loaded in LNCs compared to the absence of LNCs with a lung half-time of 8.8±0.7 hours. Bronchoalveolar fluid analysis revealed transient 7-day alveolar inflammation, reaching a maximum between days 2 and 4, characterized by a peak of granulocytes at day 1 followed by a peak of lymphocytes at day 3. Alveolar protein levels were increased at days 3 and 7. Acute inflammation was increased with paclitaxel-loaded LNCs in comparison with blank LNCs but dropped out at day 7. No histological pulmonary lesion was observed at day 60. LNCs lowered surface tension to a greater degree than Curosurf® in a physicochemical model of the pulmonary alveolus. A single pulmonary delivery of LNCs induces a short-term alveolar inflammation with no residual lesions in rats at day 60. These data permit to start the study of LNCs in surfactant replacement therapy.


Assuntos
Portadores de Fármacos/efeitos adversos , Portadores de Fármacos/farmacocinética , Pulmão/efeitos dos fármacos , Pulmão/patologia , Nanocápsulas/efeitos adversos , Aerossóis/administração & dosagem , Aerossóis/efeitos adversos , Aerossóis/química , Animais , Produtos Biológicos , Linhagem Celular , Portadores de Fármacos/administração & dosagem , Sistemas de Liberação de Medicamentos/efeitos adversos , Sistemas de Liberação de Medicamentos/métodos , Feminino , Fibrose , Humanos , Lipídeos/química , Nanocápsulas/administração & dosagem , Nanocápsulas/química , Paclitaxel/química , Paclitaxel/farmacocinética , Fosfolipídeos , Alvéolos Pulmonares/efeitos dos fármacos , Alvéolos Pulmonares/fisiopatologia , Ratos Sprague-Dawley , Tensão Superficial/efeitos dos fármacos , Distribuição Tecidual
9.
PLoS One ; 11(10): e0164626, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-27741267

RESUMO

PURPOSE: This work aims to develop, validate and optimize the radiolabeling of Starch-Based Microparticles (SBMP) by 188Re and 68Ga in the form of ready-to-use radiolabeling kits, the ultimate goal being to obtain a unique theranostic vector for the treatment of Hepatocellular Carcinoma. METHODS: Optimal labeling conditions and composition of freeze-dried kits were defined by monitoring the radiochemical purity while varying several parameters. In vitro stability studies were carried out, as well as an in vivo biodistribution as a preliminary approach with the intra-arterial injection of 68Ga radiolabeled SBMP into the hepatic artery of DENA-induced rats followed by PET/CT imaging. RESULTS: Kits were optimized for 188Re and 68Ga with high and stable radiochemical purity (>95% and >98% respectively). The in vivo preliminary study was successful with more than 95% of activity found in the liver and mostly in the tumorous part. CONCLUSION: SBMP are a promising theranostic agent for the Selective Internal Radiation Therapy of Hepatocellular carcinoma.


Assuntos
Carcinoma Hepatocelular/diagnóstico por imagem , Neoplasias Hepáticas/diagnóstico por imagem , Compostos Radiofarmacêuticos/química , Rênio/química , Amido/química , Animais , Radioisótopos de Gálio/química , Injeções Intra-Arteriais , Marcação por Isótopo , Masculino , Tomografia por Emissão de Pósitrons combinada à Tomografia Computadorizada , Compostos Radiofarmacêuticos/farmacocinética , Ratos , Ratos Wistar , Nanomedicina Teranóstica , Distribuição Tecidual
11.
EJNMMI Res ; 6(1): 21, 2016 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-26944734

RESUMO

BACKGROUND: This study is an assessment of the impact of acquisition times on SUV with [(18)F]FDG-PET/CT on healthy livers (reference organ with stable uptake over time) and on tumors. METHODS: One hundred six [(18)F]FDG-PET/CT were acquired in list mode over a single-bed position (livers (n = 48) or on tumors (n = 58)). Six independent datasets of different durations were reconstructed (from 1.5 to 10 min). SUVmax (hottest voxel), SUVpeak (maximum average SUV within a 1-cm(3) spherical volume), and SUVaverage were measured within a 3-cm-diameter volume of interest (VOI) in the right lobe of the liver. For [(18)F]FDG avid tumors (SUVmax ≥ 5), the SUVmax, SUVpeak, and SUV41% (isocontour threshold method) were computed. RESULTS: For tumors, SUVpeak values did not vary with acquisition time. SUVmax displayed significant differences between 1.5- and 5-10-min reconstruction times. SUV41% was the most time-dependent parameter. For the liver, the SUVaverage was the sole parameter that did not vary over time. CONCLUSIONS: For [(18)F]FDG avid tumors, with short acquisition times, i.e., with new generations of PET systems, the SUVpeak may be more robust than the SUVmax. The SUVaverage over a 3-cm-diameter VOI in the right lobe of the liver appears to be a good method for a robust and reproducible assessment of the hepatic metabolism.

12.
Arch Phys Med Rehabil ; 97(4): 646-649, 2016 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-26582550

RESUMO

OBJECTIVE: To assess the potential use of indium-111 diethylenetriamine pentaacetic acid ((111)In-DTPA) scintigraphy coupled with computed tomography (CT) for the investigation of intrathecal baclofen (ITB) device malfunction. DESIGN: Retrospective study of a case series of patients. SETTING: Neurosurgical and physical and rehabilitation medicine departments. PARTICIPANTS: Patients (N=7) with reduced ITB effectiveness in whom prior conventional radiographs were inconclusive. INTERVENTION: Nine (111)In-DTPA scintigraphic studies and 8 CT scans. Planar acquisitions were followed by tomoscintigraphy combined with CT. MAIN OUTCOME MEASURE: Progression of the radiotracer in the pump, catheters, and in the subarachnoid space. RESULTS: In 7 cases, scintigraphy coupled with CT showed leakage behind the pump, lack of activity outside the pump reservoir, abrupt interruption of activity in the catheter, or abnormal distribution of the radiotracer, thus demonstrating that the drug did not reach its target. Surgical revision confirmed these findings in 5 cases. In 1 case, combined imagery ruled out device dysfunction. In the remaining case, only planar acquisitions were performed, showing correct diffusion of the radiotracer. CONCLUSIONS: The combination of scintigraphy and CT provides simultaneous functional and anatomic imagery of the device. The slow infusion of the radioisotope mimics the diffusion of baclofen, and this could be a useful method to explore intrathecal device malfunction. Further studies are required to compare scintigraphy coupled with CT, to radiopaque injection followed by fluoroscopy or CT.


Assuntos
Falha de Equipamento , Bombas de Infusão Implantáveis/efeitos adversos , Injeções Espinhais/instrumentação , Ácido Pentético/análogos & derivados , Tomografia Computadorizada de Emissão/métodos , Adolescente , Adulto , Idoso , Baclofeno/administração & dosagem , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Relaxantes Musculares Centrais/administração & dosagem , Espasticidade Muscular/tratamento farmacológico , Espasticidade Muscular/etiologia , Estudos Retrospectivos , Adulto Jovem
13.
PLoS One ; 8(3): e58152, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-23516443

RESUMO

UNLABELLED: A multi-centre trial using PET requires the analysis of images acquired on different systems We designed a multi-centre trial to estimate the value of 18F-FLT-PET to predict response to neoadjuvant chemotherapy in patients with newly diagnosed breast cancer. A calibration check of each PET-CT and of its peripheral devices was performed to evaluate the reliability of the results. MATERIAL AND METHODS: 11 centres were investigated. Dose calibrators were assessed by repeated measurements of a 68Ge certified source. The differences between the clocks associated with the dose calibrators and inherent to the PET systems were registered. The calibration of PET-CT was assessed with an homogeneous cylindrical phantom by comparing the activities per unit of volume calculated from the dose calibrator measurements with that measured on 15 Regions of Interest (ROIs) drawn on 15 consecutive slices of reconstructed filtered back-projection (FBP) images. Both repeatability of activity concentration based upon the 15 ROIs (ANOVA-test) and its accuracy were evaluated. RESULTS: There was no significant difference for dose calibrator measurements (median of difference -0.04%; min = -4.65%; max = +5.63%). Mismatches between the clocks were less than 2 min in all sites and thus did not require any correction, regarding the half life of 18F. For all the PET systems, ANOVA revealed no significant difference between the activity concentrations estimated from the 15 ROIs (median of difference -0.69%; min = -9.97%; max = +9.60%). CONCLUSION: No major difference between the 11 centres with respect to calibration and cross-calibration was observed. The reliability of our 18F-FLT multi-centre clinical trial was therefore confirmed from the physical point of view. This type of procedure may be useful for any clinical trial involving different PET systems.


Assuntos
Neoplasias da Mama/diagnóstico , Didesoxinucleosídeos , Radioisótopos de Flúor , Imagem Multimodal/normas , Tomografia por Emissão de Pósitrons , Tomografia Computadorizada por Raios X , Análise de Variância , Neoplasias da Mama/tratamento farmacológico , Calibragem , Feminino , Humanos , Imagem Multimodal/instrumentação , Controle de Qualidade , Reprodutibilidade dos Testes
14.
Biomaterials ; 32(28): 6781-90, 2011 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-21705077

RESUMO

To date, glioblastoma treatments have only been palliative. In this context, locoregional drug delivery strategies, which allow for blood--brain barrier bypass and reduced systemic toxicity, are of major significance. Recent progress in nanotechnology has led to the development of colloidal carriers of radiopharmaceutics, such as lipid nanocapsules loaded with rhenium-188 (LNC(188)Re-SSS) that are implanted in the brain. In our study, we demonstrated that fractionated internal radiation using LNC(188)Re-SSS triggered remarkable survival responses in a rat orthotopic glioma model (cure rates of 83%). We also highlighted the importance of the radioactivity activity gradient obtained by combining a simple stereotactic injection (SI) with convection-enhanced delivery (CED).We assumed that the immune system played a role in the treatment's efficacy on account of the overproduction of peripheral cytokines, recruitment of immune cells to the tumor site, and memory response in long-term survivor animals. Hence, nanovectorized internal radiation therapy with activity gradients stimulating immune responses may represent a new and interesting alternative for the treatment of solid tumors such as glioblastomas.


Assuntos
Neoplasias Encefálicas/radioterapia , Portadores de Fármacos/metabolismo , Glioma/radioterapia , Terapia de Imunossupressão , Nanocápsulas/química , Radioisótopos/uso terapêutico , Rênio/uso terapêutico , Animais , Neoplasias Encefálicas/imunologia , Neoplasias Encefálicas/mortalidade , Neoplasias Encefálicas/patologia , Linhagem Celular Tumoral , Portadores de Fármacos/química , Sistemas de Liberação de Medicamentos , Feminino , Glioma/imunologia , Glioma/mortalidade , Glioma/patologia , Lipídeos/química , Teste de Materiais , Radioisótopos/química , Radioisótopos/metabolismo , Ratos , Ratos Endogâmicos F344 , Rênio/química , Rênio/metabolismo , Taxa de Sobrevida , Sobreviventes , Distribuição Tecidual
15.
PLoS One ; 6(3): e16926, 2011 Mar 07.
Artigo em Inglês | MEDLINE | ID: mdl-21408224

RESUMO

BACKGROUND: Due to their nanometric scale (50 nm) along with their biomimetic properties, lipid nanocapsules loaded with Rhenium-188 (LNC(188)Re-SSS) constitute a promising radiopharmaceutical carrier for hepatocellular carcinoma treatment as its size may improve tumor penetration in comparison with microspheres devices. This study was conducted to confirm the feasibility and to assess the efficacy of internal radiation with LNC(188)Re-SSS in a chemically induced hepatocellular carcinoma rat model. METHODOLOGY/PRINCIPAL FINDINGS: Animals were treated with an injection of LNC(188)Re-SSS (80 MBq or 120 MBq). The treated animals (80 MBq, n = 12; 120 MBq, n = 11) were compared with sham (n = 12), blank LNC (n = 7) and (188)Re-perrhenate (n = 4) animals. The evaluation criteria included rat survival, tumor volume assessment, and vascular endothelial growth factor quantification. Following treatment with LNC(188)Re-SSS (80 MBq) therapeutic efficiency was demonstrated by an increase in the median survival from 54 to 107% compared with control groups with up to 7 long-term survivors in the LNC(188)Re-SSS group. Decreased vascular endothelial growth factor expression in the treated rats could indicate alterations in the angiogenesis process. CONCLUSIONS/SIGNIFICANCE: Overall, these results demonstrate that internal radiation with LNC(188)Re-SSS is a promising new strategy for hepatocellular carcinoma treatment.


Assuntos
Carcinoma Hepatocelular/patologia , Progressão da Doença , Lipídeos/química , Neoplasias Hepáticas/patologia , Nanocápsulas/química , Rênio/química , Animais , Carcinoma Hepatocelular/sangue , Carcinoma Hepatocelular/enzimologia , Cateterismo , Modelos Animais de Doenças , Cinética , Lipídeos/farmacocinética , Neoplasias Hepáticas/sangue , Neoplasias Hepáticas/enzimologia , Imageamento por Ressonância Magnética , Masculino , Radioisótopos , Ratos , Ratos Wistar , Rênio/farmacocinética , Análise de Sobrevida , Distribuição Tecidual , Transaminases/metabolismo , Carga Tumoral , Fator A de Crescimento do Endotélio Vascular/sangue
16.
Nucl Med Commun ; 32(1): 30-6, 2011 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-21042226

RESUMO

BACKGROUND: In 2008, American consensus recommendations for performing gastric emptying (GE) scintigraphy were published. It was recommended that data are acquired only at 0, 1, 2, and 4 h and that the results are expressed as percentages of meal retention. Until now, it was established that the GE time-activity curves should have many points (every 10, 15, or 20 min) to reflect the GE process accurately and to be optimally adjusted by a mathematical model. In this study, we have evaluated the curve fitting using only a few points as proposed by the consensus protocol. MATERIALS AND METHODS: GE scintigraphy tests of 224 patients were retrospectively analyzed. Two curve fittings were done for each patient, either using data acquired every 20 min or using data acquired every hour. A comparison of these two methods was made based on the values of the computed GE parameters. RESULTS: We observed strong correlations between the two methods (r=0.81-0.99, P<0.05). Using the Bland-Altman analysis, more than 95% of the differences were included in the mean difference 95% confidence interval. The mean differences were weak with a relatively small SD and Cohen's k coefficients ranging from 0.84 to 0.93, indicating an excellent agreement between the two methods. CONCLUSION: Our results showed the feasibility and accuracy of curve fitting using only a few points. The curve fitting is easy to perform and allows the computation of reliable and reproducible parameters that reflect the whole GE process.


Assuntos
Consenso , Esvaziamento Gástrico , Cintilografia/métodos , Estômago/diagnóstico por imagem , Estômago/fisiologia , Estudos de Viabilidade , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Controle de Qualidade , Cintilografia/normas , Reprodutibilidade dos Testes , Estados Unidos
18.
Eur J Nucl Med Mol Imaging ; 37(1): 146-55, 2010 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-19662407

RESUMO

PURPOSE: In order to avoid the microbiological risks linked to human serum albumin macroaggregates (MAA) used for lung perfusion scintigraphy, we developed a new starch-based Tc-99m potential radiopharmaceutical. METHODS: Microparticles were prepared from oxidised starch coupled to natural polyamine for Tc-99m complexation. Suspensions were formulated as ready-to-use kits for easy one-step labelling procedures. RESULTS: Particle-size analysis, electron microscopy, and confocal microscopy were performed for microparticle characterisation, and gave a typical size distribution ranging from 7 to 63 microm, with a homogenous population of spherical or oval-shaped microparticles. Radiochemical purity exceeded 95%, and was stable for at least 8 h. When challenged with histidine and human plasma, labelling was also stable. Dynamic scintigraphic acquisitions and biodistribution studies conducted on healthy Wistar rats showed a tracer accumulation with more than 80% of the ID in the lungs after 15 min. CONCLUSIONS: With clinically significant characteristics such as a lung half-life of 3 h, a lung-to-vascular ratio of 900, and a lung-to-liver ratio of 90, starch-based microparticles exhibit all the qualities for an effective new lung perfusion agent.


Assuntos
Pulmão/diagnóstico por imagem , Pulmão/metabolismo , Reconhecimento Automatizado de Padrão/métodos , Compostos Radiofarmacêuticos/farmacocinética , Amido/química , Tecnécio/farmacocinética , Animais , Portadores de Fármacos/química , Marcação por Isótopo/métodos , Masculino , Tamanho da Partícula , Imagem de Perfusão/métodos , Compostos Radiofarmacêuticos/síntese química , Ratos , Ratos Wistar , Reprodutibilidade dos Testes , Sensibilidade e Especificidade , Tecnécio/química
19.
MAGMA ; 22(3): 167-74, 2009 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-19107536

RESUMO

INTRODUCTION: The aim of this work was to map E-selectin expression in a traumatic brain injury model using a newly-designed MR contrast agent. Iron cores, responsible for susceptibility effects and therefore used as T2* contrast agents, need to be coated in order to be stabilized and need to be targeted to be useful. METHODS: We have designed a molecule coating composed, at one end, of bisphosphonate to ensure anchorage of the coating on the iron core and, at the other end, of Fukuda's defined heptapeptide known to target selectin binding sites. CONCLUSION: The synthesized nanoparticles were able to non-invasively target the traumatic brain lesion, inducing a specific T2* decrease of about 25% up to at least 70 min post-injection of the targeted contrast agent.


Assuntos
Lesões Encefálicas/metabolismo , Meios de Contraste , Selectina E/metabolismo , Ferro , Óxidos , Animais , Lesões Encefálicas/diagnóstico por imagem , Lesões Encefálicas/patologia , Meios de Contraste/química , Dextranos , Difosfonatos/química , Feminino , Óxido Ferroso-Férrico , Nanopartículas de Magnetita , Nanopartículas , Oligopeptídeos/química , Polietilenoglicóis/química , Cintilografia , Ratos , Ratos Sprague-Dawley , Tecnécio
20.
J Nanosci Nanotechnol ; 7(12): 4612-7, 2007 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-18283853

RESUMO

As non-phagocytic eukaryotic cells can internalize particles < 1 microm in size, small size (25 to 110 nm) lipid nanocapsules (LNC) are proposed for the intracellular drug delivery of anticancer drugs to cancer cells. LNC of different diameters were loaded with etoposide or paclitaxel and subsequently tested for drug release kinetics and their efficiency to reduce cancer cell growth in cell culture. Relative high drug loads could be achieved and sustained drug release can be provided over a period of several days (etoposide) up to a few weeks (paclitaxel). While particle size exhibited only minor influences on the release kinetics, higher initial drug load led to a distinctly lower burst release. In a cancer cell culture model, etoposide or paclitaxel LNC showed a 4-fold or 40-fold higher efficiency, respectively than the drug solution while blank LNC were found to be less toxic than the pure drug at equivalent concentrations. The uptake and intracellular accumulation of LNC was confirmed by confocal laser scanning microscopy after fluorescence labeling of the nanocarriers. This nanoparticulate system is able to achieve efficient intracellular drug concentrations and seems to be therefore a promising therapeutic approach in cancer treatment.


Assuntos
Antineoplásicos/administração & dosagem , Etoposídeo/administração & dosagem , Lipídeos/administração & dosagem , Nanocápsulas , Paclitaxel/administração & dosagem , Antineoplásicos/farmacocinética , Linhagem Celular Tumoral , Portadores de Fármacos , Etoposídeo/farmacocinética , Humanos , Microscopia Confocal , Paclitaxel/farmacocinética
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...