Результаты поиска

Nuclear myocardial perfusion imaging with a cadmium-zinc-telluride detector technique: optimized protocol for scan time reduction.

UNLABELLED: We aimed at establishing the optimal scan time for nuclear myocardial perfusion imaging (MPI) on an ultrafast cardiac gamma-camera using a novel cadmium-zinc-telluride (CZT) solid-state detector technology. METHODS: Twenty patients (17 male; BMI range, 21.7-35.5 kg/m(2)) underwent 1-d (99m)Tc-tetrofosmin adenosine stress and rest MPI protocols, each with a 15-min acquisition on a standard dual-detector SPECT camera. All scans were immediately repeated on an ultrafast CZT camera over a 6-min acquisition time and reconstructed from list-mode raw data to obtain scan durations of 1 mi

The fate of MAb-targeted Cd(125m)Te/ZnS nanoparticles in vivo.

INTRODUCTION: Nanoparticles (NP) have potential as carriers for drugs and radioisotopes. Quantitative measures of NP biodistribution in vivo are needed to determine the effectiveness of these carriers. We have used a model system of radiolabeled quantum dots to document the competition between efficient vascular targeting and interaction of the NP with the reticuloendothelial (RE) system. METHODS: We have prepared (125m)Te-labeled CdTe NP that are capped with ZnS. Te-125m has a half-life and decay characteristics very similar to those for (125)I. The synthesized particles are stable in aqueou

Feasibility of simultaneous dual isotope acquisition for myocardial perfusion imaging with a cadmium zinc telluride camera.

BACKGROUND: We studied the impact of technetium-99m (99mTc) in the thallium-201 (201Tl) energy window (70 keV) to determine if CZT cardiac cameras allow us to perform simultaneous dual-isotope acquisition for myocardial perfusion imaging. METHODS: We included 117 consecutive patients. We injected 0.7 MBq/kg of 201Tl at stress, performed the first scan (image T1), then injected at rest 2 MBq/kg of 99mTc-tetrofosmin and immediately acquired a second scan with reconstruction in the energy window of thallium (image T2). A corrected thallium image was created by the subtraction of 99mTc downscatte

Clinical significance of right ventricular activity on treadmill thallium-201 myocardial single-photon emission computerized tomography using cadmium-zinc-telluride cameras.

OBJECTIVE: Identification of right ventricular (RV) abnormalities is important in patients with suspected coronary artery disease (CAD). RV activity can be better visualized on myocardial single-photon emission computerized tomography (SPECT) using a higher sensitivity cadmium-zinc-telluride (CZT) detector. The aim of this study was to investigate the clinical significance of RV/left ventricular (LV) uptake ratios during exercise thallium-201 SPECT using CZT detectors. PATIENTS AND METHODS: A total of 102 patients underwent treadmill ECG-gated SPECT, coronary angiography, and echocardiography

Quantitative CZT SPECT Myocardial Blood Flow for Physiological Assessment and Risk Stratification of Cardiac Allograft Vasculopathy.

BACKGROUND: Cardiac allograft vasculopathy (CAV) remains a major cause of morbidity and mortality after orthotopic heart transplantation. Although positron emission tomography myocardial perfusion imaging with quantitative myocardial blood flow (MBF) effectively detects CAV, access remains limited. Cadmium-zinc-telluride (CZT) single-photon emission computed tomography (SPECT) enables quantitative MBF assessment and may provide a more accessible alternative. However, the diagnostic and prognostic value of quantitative CZT SPECT-derived MBF for CAV is unknown. METHODS: We retrospectively studi

Characterization and cancer cell targeted imaging properties of human antivascular endothelial growth factor monoclonal antibody conjugated CdTe/ZnS quantum dots.

High luminescence quantum yield water-soluble CdTe/ZnS core/shell quantum dots (QDs) stabilized with thioglycolic acid were synthesized. QDs were chemically coupled to fully humanized antivascular endothelial growth factor165 monoclonal antibodies to produce fluorescent probes. These probes can be used to assay the biological affinity of the antibody. The properties of QDs conjugated to an antibody were characterized by ultraviolet and visible spectrophotometry, fluorescent spectrophotometry, sodium dodecyl sulfate-polyacrylamide gel electrophoresis, transmission electron microscopy and fluore

Data-driven respiratory motion tracking and compensation in CZT cameras: a comprehensive analysis of phantom and human images.

BACKGROUND: This study described a method for tracking and compensating respiratory motion in cadmium-zinc-telluride (CZT) cameras. We evaluated motion effects on myocardial perfusion imaging and assessed the usefulness of motion compensation in phantom and clinical studies. METHODS: SPECT studies were obtained from an oscillating heart phantom and 552 patients using CZT cameras with list-mode acquisition. Images were reformatted in 500-ms frames, and the activity centroid was calculated as respiratory signal. The myocardial perfusion, left ventricular (LV) wall thickness, and LV volume were

Conjugates of folic acids with BSA-coated quantum dots for cancer cell targeting and imaging by single-photon and two-photon excitation.

Bovine serum albumin (BSA)-coated CdTe/ZnS quantum dots (BSA-QDs) were selected to conjugate with folic acid (FA), forming FA-BSA-QDs. This study aims to develop these small FA-BSA-QDs (less than 10 nm) for the diagnosis of cancers in which the FA receptor (FR) is overexpressed. The enhancement of cellular uptake in FR-positive human nasopharyngeal carcinoma cells (KB cells) for FA-BSA-QDs was found by means of confocal fluorescence microscopy under single-photon and two-photon excitation. The uptake enhancement for FA-BSA-QDs was further evaluated by flow-cytometric analysis in 10(4) KB cells

High efficiency gamma camera enables ultra-low fixed dose stress/rest myocardial perfusion imaging.

AIMS: We validated a 1-day myocardial perfusion imaging (MPI) protocol using an ultra low-dose(ULD) equal for stress and rest on a cadmium zinc telluride (CZT). METHODS AND RESULTS: Fifty-six patients underwent a 1-day MPI protocol using a standard (SD) 99mTc-tetrofosmin dose at stress (320 MBq) and rest (960 MBq) with 5 min acquisition time each (SD). Within 2 weeks MPI was repeated using ULD 99mTc-tetrofosmin equal for stress and rest (160 MBq) with 15 min acquisition time each (ULD). All scans were performed on a CZT camera (DNM 570c, GE Healthcare). Background subtraction was applied on t

Comparison between N13NH3-PET and 99mTc-Tetrofosmin-CZT SPECT in the evaluation of absolute myocardial blood flow and flow reserve.

BACKGROUND: PET/CT is the standard for quantitative assessments of myocardial blood flow (MBF), but it requires short-lived-tracers, costly, and not widely available. SPECT with Cadmium Zinc Telluride (CZT) detectors allows dynamic acquisition and quantitation of MBF. The study aims were to compare MBF measurements by 99mTc-tetrofosmin-CZT to N13NH3 PET/CT after regadenoson-induced coronary hyperemia and to evaluate the effect of attenuation correction (AC). METHODS: 54 patients were evaluated at rest and during vasodilation by 99mTc-tetrofosmin-CZT and N13NH3 PET/CT within 2 weeks. MBF and M

A new era in gated myocardial perfusion imaging: Feasibility of data-driven cardiac contraction gating with multiple pinhole CZT SPECT.

BACKGROUND: We previously validated the use of a data-driven cardiac respiratory-motion (RM) correction method (REGAT) applicable to CZT SPECT myocardial perfusion imaging (MPI). In this study, we adapted the same process used with REGAT for RM to generate data-driven cardiac contraction triggers and corresponding cardiac contraction-gated SPECT studies (GSPECT-DD). We aimed to study its feasibility and compare its performances to GSPECT studies generated with ECG monitor-based triggers (GSPECT-ECG). METHODS: We included seven non-consecutive randomly chosen patients addressed for 1-day 99mTc

Gelatin microcapsules for enhanced microwave tumor hyperthermia.

Local and rapid heating by microwave (MW) irradiation is important in the clinical treatment of tumors using hyperthermia. We report here a new thermo-seed technique for the highly efficient MW irradiation ablation of tumors in vivo based on gelatin microcapsules. We achieved 100% tumor elimination in a mouse model at an ultralow power of 1.8 W without any side-effects. The results of MTT assays, a hemolysis test and the histological staining of organs indicated that the gelatin microcapsules showed excellent compatibility with the physiological environment. A possible mechanism is proposed fo

Mechanisms of cellular adaptation to quantum dots--the role of glutathione and transcription factor EB.

Cellular adaptation is the dynamic response of a cell to adverse changes in its intra/extra cellular environment. The aims of this study were to investigate the role of: (i) the glutathione antioxidant system, and (ii) the transcription factor EB (TFEB), a newly revealed master regulator of lysosome biogenesis, in cellular adaptation to nanoparticle-induced oxidative stress. Intracellular concentrations of glutathione species and activation of TFEB were assessed in rat pheochromocytoma (PC12) cells following treatment with uncapped CdTe quantum dots (QDs), using biochemical, live cell fluoresc

The prognostic value of ultra low-dose thallium myocardial perfusion protocol using CZT SPECT.

The purpose of this study was to assess the prognostic value of ultra-low dose thallium myocardial perfusion imaging. Three hundred and sixty-six patients (245 men) underwent ultra-low dose stress-redistribution imaging on CZT SPECT camera GE Discovery NM 530c. The stress test was performed by bicycle ergometry or regadenoson injection. The activity of 0.5 MBq (0.014 mCi) Tl-201 chloride per kilogram of body weight was administered. The stress images were acquired immediately and redistribution images were taken after 3 h. Patient follow-up was focused on combined end-point (death, myocardial

The influence of anthropometric and basic circulatory variables on count rate in cadmium-zinc-telluride SPECT gated radionuclide angiography.

AIM: To determine the influence of weight, height, gender, age, heart rate, and blood pressure on count rate in cadmium-zinc-telluride single-photon emission computed tomography (CZT SPECT) gated radionuclide angiography. METHOD: A total of 1,065 eligible patients referred for routine assessment of left ventricular ejection fraction were registered from August 2015 to November 2016. Data were recorded on heart rate, systolic and diastolic blood pressure, age, gender, height, weight, and count rate. All radionuclide angiographies were performed on a dedicated cardiac CZT SPECT camera, GE Disco

Altered Gene expression of ABC transporters, nuclear receptors and oxidative stress signaling in zebrafish embryos exposed to CdTe quantum dots.

Adenosine triphosphate-binding cassette (ABC) transporters, including P-glycoprotein (Pgp) and multi-resistance associated proteins (Mrps), have been considered important participants in the self-protection of zebrafish embryos against environmental pollutants, but their possible involvement in the efflux and detoxification of quantum dots (QDs), as well as their regulation mechanism are currently unclear. In this work, gene expression alterations of ABC transporters, nuclear receptors, and oxidative stress signaling in zebrafish embryos after the treatment of mercaptopropionic acid (MPA)CdTe

Stress thallium-201/rest technetium-99m sequential dual-isotope high-speed myocardial perfusion imaging validation versus invasive coronary angiography.

BACKGROUND: Recent advances in nuclear myocardial perfusion imaging (MPI) have made it possible to develop a dual-isotope protocol for high-speed acquisition with image quality and radiation delivery comparable to that obtained with conventional single isotope protocols. So far, no study has compared dual-isotope high-speed MPI to invasive coronary angiography (ICA) in a large cohort using a Cadmium-zinc-telluride SPECT system. METHODS: Over a 1-year period (May 2011 to April 2012), 1366 patients underwent dual-isotope high-speed MPI. Patients with ICA within 3 months after dual-isotope high-

pH-responsive hybrid quantum dots for targeting hypoxic tumor siRNA delivery.

Hypoxia is a characteristic of cancer and plays a key role in tumorigenesis, angiogenesis and resistance to cancer therapies. SiRNA treatment is effective against hypoxic tumors by gene silencing. However, siRNA delivery to the hypoxic regions of solid tumors still presents a challenge due to the distance from blood vessels and the increased presence of efflux transporters. Therefore, tumor therapies would be improved through the immediate development of an effective siRNA delivery system to hypoxic regions. To this end, we synthesized a system to deliver HIF-1α siRNA into hypoxic tumor cells.

Интегрин α4β7:: патогенные роли в заболеваниях метаболики и воспаления и в терапии перевода.

Интегрин α4β7 является ключевым рецептором сцепления, который является посредником лимфоцита, движущегося к кишечной слизи через взаимодействие с MAdCAM-1, VCAM-1, и фибронектин, тем самым играя центральную роль в иммунной слежке и мукозаловом иммунитете. Появляющиеся данные расширили его функциональный охват за пределы кишечного гомеостаза, с тем чтобы охватить различные подстрекательские и метаболические заболевания. В настоящем обзоре систематически резюмируются структурные характеристики, взаимодействия лигандов и положения о соответствии α.4β7, с акцентом на патогенную роль в провокационн

Совпадение в полном тексте источника
… suppressing β-cell antigen presentation and autoimmune T-cell activation. 108 Tregs similarly rely on the α4β7/MAdCAM-1 pathway to localize to islets and exert immunosuppressive functions. α4 blockade or β7-deficient Tregs fail to enter islets, impairing their protective role against diabetes. 109 Tellurium-containing …

Molecular Mechanism and Prevention Strategy of Chemotherapy- and Radiotherapy-Induced Ovarian Damage.

Fertility preservation is an emerging discipline, which is of substantial clinical value in the care of young patients with cancer. Chemotherapy and radiation may induce ovarian damage in prepubertal girls and young women. Although many studies have explored the mechanisms implicated in ovarian toxicity during cancer treatment, its molecular pathophysiology is not fully understood. Chemotherapy may accelerate follicular apoptosis and follicle reservoir utilization and damage the ovarian stroma via multiple molecular reactions. Oxidative stress and the radiosensitivity of oocytes are the main c

Совпадение в полном тексте источника
… Tellurium compound AS101 induces PC12 differentiation and rescues the neurons from apoptotic death Ann. N. Y. Acad. Sci. 2003 1010 659 666 10.1196/annals.1299.120 15033807 122. Hayun M. Naor Y. Weil M. Albeck M. Peled A. Don J. Haran-Ghera N. Sredni B. …