Demotate is a new tetraamine-functionalised [Tyr3]octreotate derivative that binds technetium-99m with a high efficiency under mild conditions. The resulting radioligand, [99mTc]Demotate, forms in a high purity and is stable for at least 6 h after labelling. The affinity of the unlabelled peptide for somatostatin receptors is high (IC(50)=0.13 n M) and comparable to that of [Tyr3]octreotate or [Tyr3]octreotide, as demonstrated by competition binding experiments in rat brain cortex or AR42J cell membrane preparations. An equally very high affinity ( K(d)=0.07 n M) was exhibited by [99mTc/99gTc]Demotate during saturation binding experiments using rat brain cortex membrane homogenates. The radioligand resisted hydrolytic degradation in mouse plasma and was excreted intact in mouse urine. In vivo, [99mTc]Demotate cleared very rapidly from non-target tissues into the bladder via the kidneys, while radioactivity uptake in target organs was very high. In mice bearing the experimental AR42J tumour, [99mTc]Demotate demonstrated a very high tumour uptake at 1 h p.i. (25%ID/g) that remained high (20%ID/g) at 4 h p.i. This uptake could be effectively blocked by co-injection of a high dose of [Tyr3]octreotate together with the radioligand. High-quality planar and single-photon emission tomographic images were acquired 1 h after injection of [99mTc]Demotate in tumour-bearing mice, illustrating the excellent properties of this agent for somatostatin receptor tumour imaging.
Clustering of biocompatible magnetic iron oxide nanocrystallites (MIONs) is a synthetic strategy which improves magnetic manipulation, imaging, and sensing for biomedical applications. In this work we describe the synthesis of condensed clustered MIONs obtained through biomineralization and epitaxial aggregation in the presence of alginate at ambient conditions, mimicking the process that so far has been achieved only by nature, in iron-oxidizing bacteria. These condensed-type magnetic nanostructures exhibit higher magnetophoretic responses compared to other types of magnetic colloids and clustered systems. The soft environmental conditions used for the synthesis of the magnetic nanosystems enables the alginate coating material to retain high drug loading ability for the doxorubicin molecule as well as strong binding proclivity for radionuclides. The strong binding of doxorubicin forms the physical basis to obtain magnetic nanocarriers, where the selective release of the drug occurs only under the action of external stimuli, such as remote magnetic hyperthermia or increased temperature (i.e., inflamed tissue). Furthermore, the strong binding proclivity of radionuclides facilitates in vivo SPECT imaging. The witnessed properties are obtained by using only ∼17 wt % alginate content in the magnetic superstructures; thus, very high saturation magnetization value is imparted to the condensed system, expressed in terms of the hybrid's mass. In spite of the fact that the magnetic nanoassemblies are characterized by low hydrodynamic diameter, ∼45 nm, the transverse relaxivity reaches the remarkable value of 250 s −1 mM −1 Fe (for negative MION contrast agents of this size), a property that validates the use of these nanostructures as effective MRI contrast agents.
Neuromuscular diseases are characterized by progressive muscle degeneration and muscle weakness resulting in functional disabilities. While each of these diseases is individually rare, they are common as a group, and a large majority lacks effective treatment with fully market approved drugs. Magnetic resonance imaging and spectroscopy techniques (MRI and MRS) are showing increasing promise as an outcome measure in clinical trials for these diseases. In 2013, the European Union funded the COST (co-operation in science and technology) action BM1304 called MYO-MRI (
www.myo-mri.eu
), with the overall aim to
advance novel MRI and MRS techniques for both diagnosis and quantitative monitoring of neuromuscular diseases through sharing of expertise and data, joint development of protocols, opportunities for young researchers and creation of an online atlas of muscle MRI and MRS
. In this report, the topics that were discussed in the framework of working group 3, which had the objective to:
Explore new contrasts, new targets and new imaging techniques for NMD
are described. The report is written by the scientists who attended the meetings and presented their data. An overview is given on the different contrasts that MRI can generate and their application, clinical needs and desired readouts, and emerging methods.
Early
cancer detection and perfect understanding of the disease
are imperative toward efficient treatments. It is straightforward
that, for choosing a specific cancer treatment methodology, diagnostic
agents undertake a critical role. Imaging is an extremely intriguing
tool since it assumes a follow up to treatments to survey the accomplishment
of the treatment and to recognize any conceivable repeating injuries.
It also permits analysis of the disease, as well as to pursue treatment
and monitor the possible changes that happen on the tumor. Likewise,
it allows screening the adequacy of treatment and visualizing the
state of the tumor. Additionally, when the treatment is finished,
observing the patient is imperative to evaluate the treatment methodology
and adjust the treatment if necessary. The goal of this review is
to present an overview of conjugated photosensitizers for imaging
and therapy.
The ability of iron-doped hydroxyapatite nanoaprticles (FeHA) to work in vivo as imaging agents for magnetic resonance (MR) and nuclear imaging is demonstrated. FeHA applied an higher MR contrast in the liver, spleen and kidneys of mice with respect to Endorem®. The successful radiolabeling of FeHA allowed for scintigraphy/X-ray and ex vivo biodistribution studies, confirming MR results and envisioning FeHA application for dual-imaging.
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