جستجوی مقالات مرتبط با کلیدواژه « contrast agents » در نشریات گروه « پزشکی »

Hybrid nanoparticles have emerged as promising tools in cancer diagnosis and treatment, offering the potential for early detection and precise eradication of malignant cells by integrating diverse materials. However, navigating the intricacies, limitations, and hurdles within this domain underscores the importance of thoughtful decision-making. This editorial provides a comprehensive exploration of the merits and challenges of nanotechnology in the context of cancer diagnosis, therapy, and theranostics. It sheds light on the current applications and delves into the promising future prospects in this field. By doing so, this editorial aims to foster a deeper understanding of the intricacies involved in designing efficient protocols for hybrid nanoparticle production, contributing to advancing cancer management strategies.

Increasing research has been focused on the development of various nanocomplexes as targeted contrastmedia in diagnostic modalities, mainly in computed tomography (CT) scan imaging. Herein, we report a new methodthat uses Triptorelin [a luteinizing hormone-releasing hormone (LHRH) agonist]-targeted gold nanoparticles (AuNPs)via alginate for early detection of cancer by molecular CT imaging. In the experimental study, the formed multifunctional AuNPs coated with alginate conjugatedwith Triptorelin peptide (Triptorelin-Alginate-AuNPs) were synthesized and characterized via different techniques,including transmission electron microscopy (TEM), dynamic light scattering (DLS), and fourier transform infrared (FTIR)spectroscopy. The MTT assay was applied to calculate the toxicity of the NPs. The results indicated that the formed Triptorelin-Alginate-AuNPs with an Au core size of ~18 nm arenoncytotoxic at 127-, 254-, 381- and 508-mM concentrations and revealed significant improvement in the attenuationof X-rays intensity and contrast to noise ratio (CNR), compared with non-targeted cells at the highest energies (90, 120,140 kVp). At 90 kVp, compared to non-targeted cells, targeted cells (Triptorelin-Alginate-AuNPs) enable 1.58, 1.69, 3.7and 3.43 times greater contrast at a concentration of 127 mM, 254 mM, 381 mM, and 508 mM, respectively. These results suggest that the developed Triptorelin-Alginate-AuNPs may be considered an effectivecontrast agent for molecular CT imaging of gonadotropin-releasing hormone (GnRH) receptor-expressing cancer cells.

Gadolinium (Gd3+) is a chemical element belonging to the lanthanide group and commonly used in magnetic resonance imaging (MRI) as a contrast agent. However, recently, gadolinium has been reported deposition in the body after a patient receives multiple injections. Gadolinium is a potent block and competes with calcium diffusion into the presynaptic. There has not been a precise mechanism of gadolinium blocking calcium channel as a channel of calcium diffusion to presynaptic until now.

This study aims to investigate the mechanism of calcium influx model and the effect of neurotransmitter release to the synaptic cleft influenced by the presence of Gd3+.

Monte Carlo Cell simulation was used to analyze simulation and also Blender was used to create and visualize the model for synapse. The synapse modeled by a form resembling the actual synapse base on a spherical shape.

The presence of gadolinium around the presynaptic has been disturbing diffusion of calcium influx presynaptic. The result shows that the presence of gadolinium around the presynaptic has caused a decrease in the amount of calcium influx presynaptic. These factors contribute to reducing the establishment of the active membrane, then the amount of synaptic vesicle docking and finally the amount of released neurotransmitter.

Gadolinium and calcium compete with each other across of calcium channel. The presence of gadolinium has caused a chain effect for signal transmission at the chemical synapse, reducing the amount of active membrane, synaptic vesicle docking, and releasing neurotransmitter.

The aim of the study was to evaluate the potential of manganese‑zinc ferrite nanoparticles (MZF NPs) as a novel negative magnetic resonance imaging (MRI) contrast agents for 4T1 (mouse mammary carcinoma) and L929 (murine fibroblast) cell lines.

MZF NPs and its suitable coating, polyethylene glycol (PEG) via covalent bonding, were investigated under in vitro condition. The cytotoxicity of MZF NPs was tested by 3‑(4,5‑dimethyl thiazolyl‑2)‑2,5‑diphenyltetrazolium bromide assay after 12 and 24 h of incubation. To evaluate the potential of MZF NPs as T2 MRI nanocontrast agent, images were obtained from phantom containing different Fe concentrations and T2 relaxivity (r2) was measured. The viability of both 4T1 breast cancer and L929 murine fibroblast cell lines incubated with different Fe concentrations.

In vitro T2‑weighted MRI showed that signal intensity of 4T1 cells was lower than that of L929 as control cells. T2‑weighted MRI showed that signal intensity of MZF NPs enhanced with increasing concentration of NPs. The values of 1/T2 relaxivity (r2) for coated MZF NPs with PEG found to be 85.5 mM−1 s−1 which is higher than that of commercially clinical used (Sinerem) MRI contrast agent.

The results showed that MZF NPs have potential to detect breast cancer cells (4T1) and also have high contrast resolution between normal (L929) and cancerous cells (4T1) which is a suitable nanoprobe for T2‑weighted MR imaging contrast agents.

Radiofrequency ablation (RFA) is not feasible when hepatocellular carcinoma (HCC) is poorly defined or invisible on conventional gray-scale ultrasonography (GSUS). Recent introduction of contrast-enhanced ultrasonography (CEUS) helps diagnose HCC by showing its typical enhancement pattern.
The purpose of this study is to demonstrate the added value of CEUS as a RFA planning modality for HCC compared with conventional GSUS.
Patients and A total of 64 HCCs from 57 patients (men:women = 41:16; mean age, 62.6) who had undergone GSUS and CEUS for RFA planning in 2011 were retrospectively reviewed. Ultrasound contrast agent was used for CEUS after conventional GSUS. The recorded images of GSUS and CEUS were reviewed retrospectively. On GSUS, the size, location, echogenicity, and margin of each HCC were reviewed. The visibility scores of HCC on GSUS and CEUS were measured using a 3-point scale. GSUS visibility score: score 1, definite nodule with well-defined margin; score 2, slightly hypo-/hyperechoic nodule with partial margin; score 3, isoechoic nodule without margin. CEUS visibility score: score 1, arterial enhancement; score 2, only delay washout; score 3, no arterial enhancement or washout.
The mean size of HCCs was 1.8 cm (range, 1.0 - 4.8 cm). Among 64 HCCs, visibility score 1 were 37; score 2, 8; score 3, 19 on GSUS. By performing CEUS, 10 out of 19 HCCs with GSUS visibility score 3 showed CEUS visibility score 1. Seven out of 8 HCCs with GSUS visibility score 2 showed CEUS visibility score 1. Total 37 HCCs showed visibility score 1 on GSUS; whereas, 53 HCCs showed visibility score 1 on CEUS (57.8% vs. 82.8%).
CEUS can be an effective RFA planning modality when a target HCC is invisible or questionable on GSUS.

Magnetic resonance imaging is an exclusive imaging method which can distinguish injured tissues from the healthy tissues or organs without using ionizing radiation. Magnetic resonance imaging is able to provide quantitative data regarding the anatomical and physiological features of each specific organ. Magnetic resonance imaging is a non-invasive method, but contrast agents are necessary to enhance the visualization of inaccessible organs in some organs such as gastrointestinal (GI) imaging. Various types of contrast agents have been used in studies including intravascular administration and oral materials. Oral contrast agents can be the artificial materials or natural factors. Natural contrast agents consist of fruit juice or pulps. Some advantages have been reported regarding the natural types of contrast agents over the artificial agents including better taste and tolerability. We briefly reviewed the different types of contrast agents and focused on the studies in which natural oral contrast agents used to investigate their efficacy in increasing the gastrointestinal magnetic resonance imaging clarity.