Focal Laser Ablation of Prostate Cancer: Phase I Clinical Trial

PURPOSE

Focal laser ablation is an investigational technique to treat prostate cancer in a region confined manner via coagulative necrosis. This phase I trial primarily examines the safety of transrectal magnetic resonance imaging guided (in-bore) focal laser ablation in men with intermediate risk prostate cancer. An exploratory end point is cancer control after 6 months.

MATERIALS AND METHODS

In an institutional review board approved trial we studied focal laser ablation in 8 men with intermediate risk prostate cancer diagnosed using magnetic resonance-ultrasound fusion. Focal laser ablation was performed by inserting a cylindrically diffusing, water cooled laser fiber into magnetic resonance visible regions of interest, followed by interstitial heating at 10 to 15 W for up to 3 minutes. Secondary safety monitors (thermal probes) were inserted to assess the accuracy of magnetic resonance thermometry. Comprehensive magnetic resonance-ultrasound fusion biopsy was performed after 6 months. Adverse events and health related quality of life questionnaires were recorded.

RESULTS

Focal laser ablation was successfully performed in all 8 subjects. No grade 3 or greater adverse events occurred and no changes in International Prostate Symptom Score or International Index of Erectile Function 5 were observed. Ablation zones, as measured by posttreatment magnetic resonance imaging, had a median volume of 3 cc or 7.7% of prostate volume. Prostate specific antigen decreased in 7 men (p <0.01). At followup magnetic resonance-ultrasound fusion biopsy cancer was not detected in the ablation zone in 5 men but was present outside the treatment margin in 6 men.

CONCLUSIONS

Focal laser ablation of the prostate is feasible and safe in men with intermediate risk prostate cancer without serious adverse events or changes in urinary or sexual function at 6 months. Comprehensive biopsy followup indicates that larger treatment margins than previously thought necessary may be required for complete tumor ablation.

Analysis of Neural-BOLD Coupling Through Four Models of the Neural Metabolic Demand

The coupling of the neuronal energetics to the blood-oxygen-level-dependent (BOLD) response is still incompletely understood. To address this issue, we compared the fits of four plausible models of neurometabolic coupling dynamics to available data for simultaneous recordings of the local field potential and the local BOLD response recorded from monkey primary visual cortex over a wide range of stimulus durations. The four models of the metabolic demand driving the BOLD response were: direct coupling with the overall LFP; rectified coupling to the LFP; coupling with a slow adaptive component of the implied neural population response; and coupling with the non-adaptive intracellular input signal defined by the stimulus time course. Taking all stimulus durations into account, the results imply that the BOLD response is most closely coupled with metabolic demand derived from the intracellular input waveform, without significant influence from the adaptive transients and nonlinearities exhibited by the LFP waveform.

Structural and functional connectivity in healthy aging: Associations for cognition and motor behavior

Age-related behavioral declines may be the result of deterioration of white matter tracts, affecting brain structural (SC) and functional connectivity (FC) during resting state. To date, it is not clear if the combination of SC and FC data could better predict cognitive/motor performance than each measure separately. We probed these relationships in the cingulum bundle, a major white matter pathway of the default mode network. We aimed to attain deeper knowledge about: (a) the relationship between age and the cingulum's SC and FC strength, (b) the association between SC and FC, and particularly (c) how the cingulum's SC and FC are related to cognitive/motor performance separately and combined. We examined these associations in a healthy and well-educated sample of 165 older participants (aged 64-85). SC and FC were acquired using probabilistic tractography to derive measures to capture white matter integrity within the cingulum bundle (fractional anisotropy, mean, axial and radial diffusivity) and a seed-based resting-state functional MRI correlation approach, respectively. Participants performed cognitive tests measuring processing speed, memory and executive functions, and motor tests measuring motor speed and grip force. Our data revealed that only SC but not resting state FC was significantly associated with age. Further, the cingulum's SC and FC showed no relation. Different relationships between cognitive/motor performance and SC/FC separately were found, but no additive effect of the combined analysis of cingulum's SC and FC for predicting cognitive/motor performance was apparent.

Multimodal SHG-2PF Imaging of Microdomain Ca2+-Contraction Coupling in Live Cardiac Myocytes

RATIONALE

Cardiac myocyte contraction is caused by Ca(2+) binding to troponin C, which triggers the cross-bridge power stroke and myofilament sliding in sarcomeres. Synchronized Ca(2+) release causes whole cell contraction and is readily observable with current microscopy techniques. However, it is unknown whether localized Ca(2+) release, such as Ca(2+) sparks and waves, can cause local sarcomere contraction. Contemporary imaging methods fall short of measuring microdomain Ca(2+)-contraction coupling in live cardiac myocytes.

OBJECTIVE

To develop a method for imaging sarcomere level Ca(2+)-contraction coupling in healthy and disease model cardiac myocytes.

METHODS AND RESULTS

Freshly isolated cardiac myocytes were loaded with the Ca(2+)-indicator fluo-4. A confocal microscope equipped with a femtosecond-pulsed near-infrared laser was used to simultaneously excite second harmonic generation from A-bands of myofibrils and 2-photon fluorescence from fluo-4. Ca(2+) signals and sarcomere strain correlated in space and time with short delays. Furthermore, Ca(2+) sparks and waves caused contractions in subcellular microdomains, revealing a previously underappreciated role for these events in generating subcellular strain during diastole. Ca(2+) activity and sarcomere strain were also imaged in paced cardiac myocytes under mechanical load, revealing spontaneous Ca(2+) waves and correlated local contraction in pressure-overload-induced cardiomyopathy.

CONCLUSIONS

Multimodal second harmonic generation 2-photon fluorescence microscopy enables the simultaneous observation of Ca(2+) release and mechanical strain at the subsarcomere level in living cardiac myocytes. The method benefits from the label-free nature of second harmonic generation, which allows A-bands to be imaged independently of T-tubule morphology and simultaneously with Ca(2+) indicators. Second harmonic generation 2-photon fluorescence imaging is widely applicable to the study of Ca(2+)-contraction coupling and mechanochemotransduction in both health and disease.

Main applications of hybrid PET-MRI contrast agents: a review

In medical imaging, the continuous quest to improve diagnostic performance and optimize treatment strategies has led to the use of combined imaging modalities. Positron emission tomography (PET) and computed tomography (CT) is a hybrid imaging existing already for many years. The high spatial and contrast resolution of magnetic resonance imaging (MRI) and the high sensitivity and molecular information from PET imaging are leading to the development of this new hybrid imaging along with hybrid contrast agents. To create a hybrid contrast agent for PET-MRI device, a PET radiotracer needs to be combined with an MRI contrast agent. The most common approach is to add a radioactive isotope to the surface of a small superparamagnetic iron oxide (SPIO) particle. The resulting agents offer a wide range of applications, such as pH variation monitoring, non-invasive angiography and early imaging diagnosis of atherosclerosis. Oncology is the most promising field with the detection of sentinel lymph nodes and the targeting of tumor neoangiogenesis. Oncology and cardiovascular imaging are thus major areas of development for hybrid PET-MRI imaging systems and hybrid contrast agents. The aim is to combine high spatial resolution, high sensitivity, morphological and functional information. Future prospects include the use of specific antibodies and hybrid multimodal PET-MRI-ultrasound-fluorescence imaging with the potential to provide overall pre-, intra- and postoperative patient care.

Bottom-Up Synthesis of Metal-Ion-Doped WS₂ Nanoflakes for Cancer Theranostics

Recently, two-dimensional transition metal dichalcogenides (TMDCs) have received tremendous attention in many fields including biomedicine. Herein, we develop a general method to dope different types of metal ions into WS2 nanoflakes, a typical class of TMDCs, and choose Gd(3+)-doped WS2 (WS2:Gd(3+)) with polyethylene glycol (PEG) modification as a multifunctional agent for imaging-guided combination cancer treatment. While WS2 with strong near-infrared (NIR) absorbance and X-ray attenuation ability enables contrasts in photoacoustic (PA) imaging and computed tomography (CT), Gd(3+) doping offers the nanostructure a paramagnetic property for magnetic resonance (MR) imaging. As revealed by trimodal PA/CT/MR imaging, WS2:Gd(3+)-PEG nanoflakes showed efficient tumor homing after intravenous injection. In vivo cancer treatment study further uncovered that WS2:Gd(3+)-PEG could not only convert NIR light into heat for photothermal therapy (PTT) but also enhance the ionizing irradiation-induced tumor damage to boost radiation therapy (RT). Owing to the improved tumor oxygenation after the mild PTT, the combination of PTT and RT induced by WS2:Gd(3+)-PEG resulted in a remarkable synergistic effect to destroy cancer. Our work highlights the promise of utilizing inherent physical properties of TMDC-based nanostructures, whose functions could be further enriched by elementary doping, for applications in multimodal bioimaging and synergistic cancer therapy.

Coherent Raman Scattering Microscopy in Biology and Medicine

Advancements in coherent Raman scattering (CRS) microscopy have enabled label-free visualization and analysis of functional, endogenous biomolecules in living systems. When compared with spontaneous Raman microscopy, a key advantage of CRS microscopy is the dramatic improvement in imaging speed, which gives rise to real-time vibrational imaging of live biological samples. Using molecular vibrational signatures, recently developed hyperspectral CRS microscopy has improved the readout of chemical information available from CRS images. In this article, we review recent achievements in CRS microscopy, focusing on the theory of the CRS signal-to-noise ratio, imaging speed, technical developments, and applications of CRS imaging in bioscience and clinical settings. In addition, we present possible future directions that the use of this technology may take.

(177)Lu-Labeled Cerasomes Encapsulating Indocyanine Green for Cancer Theranostics

This Article reported the fabrication of a robust theranostic cerasome encapsulating indocyanine green (ICG) by incorporating 1,2-distearoyl-sn-glycero-3-phosphoethanolamine-N-[carboxy(polyethylene glycol)2000]-1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid monoamide (DSPE-PEG2000-DOTA), followed by chelating radioisotope of (177)Lu. Its applications in optical and nuclear imaging of tumor uptake and biodistribution, as well as photothermal killing of cancer cells, were investigated. It was found that the obtained cerasome could act efficiently as fluorescence contrast agent as well as nuclear imaging tracer. Encapsulating ICG into cerasome could protect ICG from degradation, aggregation, and fast elimination from body, resulting in remarkable improvement in near-infrared fluorescence imaging, photothermal stability, and in vivo pharmacokinetic profile. Both fluorescence and nuclear imaging showed that such agent could selectively accumulate in tumor site after intravenous injection of the cerasome agent into Lewis lung carcinoma tumor bearing mice, resulting in efficient photothermal ablation of tumor through a one-time NIR laser irradiation at the best time window. The ability to track the uptake of cerasomes on a whole body basis could provide researchers with an excellent tool for developing cerasome-based drug delivery agents, especially the strategy of labeling cerasomes with theranostic radionuclide (177)Lu, enabling the ability of the (177)Lu-labeled cerasomes for radionuclide cancer therapy and even the combined therapy.

Multimodal and multiplex spectral imaging of rat cornea ex vivo using a white-light laser source

We applied our multimodal nonlinear spectral imaging microscope to the measurement of rat cornea. We successfully obtained multiple nonlinear signals of coherent anti-Stokes Raman scattering (CARS), third-order sum frequency generation (TSFG), and second harmonic generation (SHG). Depending on the nonlinear optical processes, the cornea tissue was visualized with different image contrast mechanism simultaneously. Due to white-light laser excitation, multiplex CARS and TSFG spectra were obtained. Combined multimodal and spectral analysis clearly elucidated the layered structure of rat cornea with molecular structural information. This study indicates that our multimodal nonlinear spectral microscope is a promising bioimaging method for tissue study. Multimodal nonlinear spectral images of rat cornea at corneal epithelium and corneal stroma in the in-plane (XY) direction. With use of the combinational analysis of different nonlinear optical processes, detailed molecular structural information is available without staining or labelling.

Multimodal Partial-Volume Correction: Application to 18F-Fluoride PET/CT Bone Metastases Studies

(18)F-fluoride PET/CT offers the opportunity for accurate skeletal metastasis staging, compared with conventional imaging methods. (18)F-fluoride is a bone-specific tracer whose uptake depends on osteoblastic activity. Because of the resulting increase in bone mineralization and sclerosis, the osteoblastic process can also be detected morphologically in CT images. Although CT is characterized by high resolution, the potential of PET is limited by its lower spatial resolution and the resulting partial-volume effect. In this context, the synergy between PET and CT presents an opportunity to resolve this limitation using a novel multimodal approach called synergistic functional-structural resolution recovery (SFS-RR). Its performance is benchmarked against current resolution recovery technology using the point-spread function (PSF) of the scanner in the reconstruction procedure.

METHODS

The SFS-RR technique takes advantage of the multiresolution property of the wavelet transform applied to both functional and structural images to create a high-resolution PET image that exploits the structural information of CT. Although the method was originally conceived for PET/MR imaging of brain data, an ad hoc version for whole-body PET/CT is proposed here. Three phantom experiments and 2 datasets of metastatic bone (18)F-fluoride PET/CT images from primary prostate and breast cancer were used to test the algorithm performances. The SFS-RR images were compared with the manufacturer's PSF-based reconstruction using the standardized uptake value (SUV) and the metabolic volume as metrics for quantification.

RESULTS

When compared with standard PET images, the phantom experiments showed a bias reduction of 14% in activity and 1.3 cm(3) in volume estimates for PSF images and up to 20% and 2.5 cm(3) for the SFS-RR images. The SFS-RR images were characterized by a higher recovery coefficient (up to 60%) whereas noise levels remained comparable to those of standard PET. The clinical data showed an increase in the SUV estimates for SFS-RR images up to 34% for peak SUV and 50% for maximum SUV and mean SUV. Images were also characterized by sharper lesion contours and better lesion detectability.

CONCLUSION

The proposed methodology generates PET images with improved quantitative and qualitative properties. Compared with standard methods, SFS-RR provides superior lesion segmentation and quantification, which may result in more accurate tumor characterization.

Multimodal cancer imaging using lanthanide-based upconversion nanoparticles

Multimodal nanoprobes that integrate different imaging modalities in one nano-system could offer synergistic effect over any modality alone to satisfy the higher requirements on the efficiency and accuracy for clinical diagnosis and medical research. Upconversion nanoparticles (UCNPs), particularly lanthanide (Ln)-based NPs have been regarded as an ideal building block for constructing multimodal bioprobes due to their fascinating properties. In this review, we first summarize recent advances in the optimizations of existing UCNPs. In particular, we highlight the applications of Ln-based UCNPs for multimodal cancer imaging in vitro and in vivo. The explorations of UCNPs-based multimodal nanoprobes for targeting diagnosis and imaging-guided therapeutics are also presented. Finally, the challenges and perspectives of Ln-based UCNPs in this rapid growing field are discussed.

Imaging Modalities to Assess Oxygen Status in Glioblastoma

Hypoxia, the result of an inadequacy between a disorganized and functionally impaired vasculature and the metabolic demand of tumor cells, is a feature of glioblastoma. Hypoxia promotes the aggressiveness of these tumors and, equally, negatively correlates with a decrease in outcome. Tools to characterize oxygen status are essential for the therapeutic management of patients with glioblastoma (i) to refine prognosis, (ii) to adapt the treatment regimen, and (iii) to assess the therapeutic efficacy. While methods that are focal and invasive in nature are of limited use, non-invasive imaging technologies have been developed. Each of these technologies is characterized by its singular advantages and limitations in terms of oxygenation status in glioblastoma. The aim of this short review is, first, to focus on the interest to characterize hypoxia for a better therapeutic management of patients and, second, to discuss recent and pertinent approaches for the assessment of oxygenation/hypoxia and their direct implication for patient care.

Multimodal imaging of bone metastases: From preclinical to clinical applications

Metastases to the skeletal system are commonly observed in cancer patients, highly affecting the patients' quality of life. Imaging plays a major role in detection, follow-up, and molecular characterisation of metastatic disease. Thus, imaging techniques have been optimised and combined in a multimodal and multiparametric manner for assessment of complementary aspects in osseous metastases. This review summarises both application of the most relevant imaging techniques for bone metastasis in preclinical models and the clinical setting.

NaGdF4:Yb(3+)/Er(3+)@NaGdF4:Nd(3+)@Sodium-Gluconate: Multifunctional and Biocompatible Ultrasmall Core-Shell Nanohybrids for UCL/MR/CT Multimodal Imaging

Multimodal bioimaging nanoparticles by integrating diverse imaging ingredients into one system, represent a class of emerging advanced materials that provide more comprehensive and accurate clinical diagnostics than conventional contrast agents. Here monodisperse and biocompatible core-shell nanoparticles, NaGdF4: Yb(3+)/Er(3+)@NaGdF4:Nd@sodium-gluconate (termed as GNa-Er@Nd), with about 26 nm in diameter were successfully prepared by a facile two step reactions in high boiling solvents, and followed a ligand exchange process with sodium gluconate. The resulting GNa-Er@Nd nanoparticles were well characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD), Fourier transform infrared spectra (FTIR), and zeta potentials. These nanohybrids present brightly dual-wavelength excited upconversion luminescence (UCL) under both 980 and 793 nm laser because of the synergistic effect of Yb(3+)/Er(3+) and Nd(3+). They also exhibited excellent relaxivity parameters (r1) in magnetic resonance imaging (MRI) and Hounsfield units (HU) in X-ray computed tomography (CT) that are comparable to the clinical contrast agents. Therefore, these small and monodisperse nanoparticles provide options to construct a unique platform for potential multimodal UCL/CT/MRI imaging simultaneously.

Stable confinement of positron emission tomography and magnetic resonance agents within carbon nanotubes for bimodal imaging

AIMS

Simultaneous positron emission tomography/MRI has recently been introduced to the clinic and dual positron emission tomography/MRI probes are rare and of growing interest. We have developed a strategy for producing multimodal probes based on a carbon nanotube platform without the use of chelating ligands.

MATERIALS & METHODS

Gd(3+) and (64)Cu(2+) ions were loaded into ultra-short single-walled carbon nanotubes by sonication. Normal, tumor-free athymic nude mice were injected intravenously with the probe and imaged over 48 h.

RESULTS & CONCLUSION

The probe was stable for up to 24 h when challenged with phosphate-buffered saline and mouse serum. Positron emission tomography imaging also confirmed the stability of the probe in vivo for up to 48 h. The probe was quickly cleared from circulation, with enhanced accumulation in the lungs. Stable encapsulation of contrast agents within ultra-short single-walled carbon nanotubes represents a new strategy for the design of advanced imaging probes with variable multimodal imaging capabilities.

Visualization of delayed release of compounds from pH-sensitive capsules in vitro and in vivo in a hamster model

Delayed controlled release is an innovative strategy to locally administer therapeutic compounds (e.g. chemotherapeutics, antibodies etc.). This would improve efficiency and reduce side effects compared with systemic administration. To enable the evaluation of the efficacy of controlled release strategies both in vitro and in vivo, we investigated the release of contrast agents ((19)F-FDG and BaSO4) to the intestinal tract from capsules coated with pH-sensitive polymers (EUDRAGIT L-100) by using two complementary techniques, i.e. (19)F magnetic resonance imaging (MRI) and computed tomography (CT). Using in vitro (19)F-MRI, we were able to non-destructively and dynamically establish a time window of 2 h during which the capsules are resistant to low pH. With (19)F-MRI, we could establish the exact time point when the capsules became water permeable, before physical degradation of the capsule. This was complemented by CT imaging, which provided longitudinal information on physical degradation of the capsule at low pH that was only seen after 230 min. After oral administration to hamsters, (19)F-MRI visualized the early event whereby the capsule becomes water permeable after 2 h. Additionally, using CT, the integrity and location (stomach and small intestines) of the capsule after administration could be monitored. In conclusion, we propose combined (19)F-MRI and CT to non-invasively visualize the different temporal and spatial events regarding the release of compounds, both in an in vitro setting and in the gastrointestinal tract of small animal models. This multimodal imaging approach will enable the in vitro and in vivo evaluation of further technical improvements to controlled release strategies.

Interactions between glutamate, dopamine, and the neuronal signature of response inhibition in the human striatum

Response inhibition is a basic mechanism in cognitive control and dysfunctional in major psychiatric disorders. The neuronal mechanisms are in part driven by dopamine in the striatum. Animal data suggest a regulatory role of glutamate on the level of the striatum. We used a trimodal imaging procedure of the human striatum including F18-DOPA positron emission tomography, proton magnetic resonance spectroscopy, and functional magnetic resonance imaging of a stop signal task. We investigated dopamine synthesis capacity and glutamate concentration in vivo and their relation to functional properties of response inhibition. A mediation analysis revealed a significant positive association between dopamine synthesis capacity and inhibition-related neural activity in the caudate nucleus. This relationship was significantly mediated by striatal glutamate concentration. Furthermore, stop signal reaction time was inversely related to striatal activity during inhibition. The data show, for the first time in humans, an interaction between dopamine, glutamate, and the neural signature of response inhibition in the striatum. This finding stresses the importance of the dopamine-glutamate interaction for behavior and may facilitate the understanding of psychiatric disorders characterized by impaired response inhibition.

Smart Albumin-Biomineralized Nanocomposites for Multimodal Imaging and Photothermal Tumor Ablation

Smart cyanine-grafted gadolinium oxide nanocrystals (Cy-GdNCs) obtained by albumin-based biomineralization are shown to be theranostic nanocomposites, with promising properties for trimodal near-infrared fluorescence/photoacoustics/magnetic-resonance imaging-guided photothermal tumor ablation.

Single-Step Assembly of Multimodal Imaging Nanocarriers: MRI and Long-Wavelength Fluorescence Imaging

Magnetic resonance imaging (MRI)- and near-infrared (NIR)-active, multimodal composite nanocarriers (CNCs) are prepared using a simple one-step process, flash nanoprecipitation (FNP). The FNP process allows for the independent control of the hydrodynamic diameter, co-core excipient and NIR dye loading, and iron oxide-based nanocrystal (IONC) content of the CNCs. In the controlled precipitation process, 10 nm IONCs are encapsulated into poly(ethylene glycol) (PEG) stabilized CNCs to make biocompatible T2 contrast agents. By adjusting the formulation, CNC size is tuned between 80 and 360 nm. Holding the CNC size constant at an intensity weighted average diameter of 99 ± 3 nm (PDI width 28 nm), the particle relaxivity varies linearly with encapsulated IONC content ranging from 66 to 533 × 10(-3) m(-1) s(-1) for CNCs formulated with 4-16 wt% IONC. To demonstrate the use of CNCs as in vivo MRI contrast agents, CNCs are surface functionalized with liver-targeting hydroxyl groups. The CNCs enable the detection of 0.8 mm(3) non-small cell lung cancer metastases in mice livers via MRI. Incorporating the hydrophobic, NIR dye tris-(porphyrinato)zinc(II) into CNCs enables complementary visualization with long-wavelength fluorescence at 800 nm. In vivo imaging demonstrates the ability of CNCs to act both as MRI and fluorescent imaging agents.

Physiologic imaging in acute stroke: Patient selection

Treatment of acute stroke is changing, as endovascular intervention becomes an important adjunct to tissue plasminogen activator. An increasing number of sophisticated physiologic imaging techniques have unique advantages and applications in the evaluation, diagnosis, and treatment-decision making of acute ischemic stroke. In this review, we first highlight the strengths, weaknesses, and possible indications for various stroke imaging techniques. How acute imaging findings in each modality have been used to predict functional outcome is discussed. Furthermore, there is an increasing emphasis on using these state-of-the-art imaging modalities to offer maximal patient benefit through IV therapy, endovascular thrombolytics, and clot retrieval. We review the burgeoning literature in the determination of stroke treatment based on acute, physiologic imaging findings.

Multifunctional Nano-Bioprobes Based on Rattle-Structured Upconverting Luminescent Nanoparticles

Lanthanide-doped upconversion nanoparticles (UCNPs) have shown great promise in versatile bioapplications. For the first time, organosilica-shelled β-NaLuF4:Gd/Yb/Er nanoprobes with a rattle structure have been designed for dual-modal imaging and photodynamic therapy (PDT). Benefiting from the unique rattle structure and aromatic framework, these nanoprobes are endowed with a high loading capacity and the disaggregation effect of photosensitizers. After loading of β-carboxyphthalocyanine zinc or rose Bengal into the nanoprobes, we achieved higher energy transfer efficiency from UCNPs to photosensitizers as compared to those with conventional core-shell structure or with pure-silica shell, which facilitates a large production of singlet oxygen and thus an enhanced PDT efficacy. We demonstrated the use of these nanoprobes in proof-of-concept X-ray computed tomography (CT) and UC imaging, thus revealing the great potential of this multifunctional material as an excellent nanoplatform for cancer theranostics.

Neuroimaging studies of social cognition in schizophrenia

Impaired social cognition is considered a core contributor to unfavorable psychosocial functioning in schizophrenia. Rather than being a unitary process, social cognition is a collection of multifaceted processes that recruit multiple brain structures, thus structural and functional neuroimaging techniques are ideal methodologies for revealing the underlying pathophysiology of impaired social cognition. Many neuroimaging studies have suggested that in addition to white-matter deficits, schizophrenia is associated with decreased gray-matter volume in multiple brain areas, especially fronto-temporal and limbic regions. However, few schizophrenia studies have examined associations between brain abnormalities and social cognitive disabilities. During the last decade, we have investigated structural brain abnormalities in schizophrenia using high-resolution magnetic resonance imaging, and our findings have been confirmed by us and others. By assessing different types of social cognitive abilities, structural abnormalities in multiple brain regions have been found to be associated with disabilities in social cognition, such as recognition of facial emotion, theory of mind, and empathy. These structural deficits have also been associated with alexithymia and quality of life in ways that are closely related to the social cognitive disabilities found in schizophrenia. Here, we overview a series of neuroimaging studies from our laboratory that exemplify current research into this topic, and discuss how it can be further tackled using recent advances in neuroimaging technology.

High sensitivity and high resolution element 3D analysis by a combined SIMS-SPM instrument

Using the recently developed SIMS-SPM prototype, secondary ion mass spectrometry (SIMS) data was combined with topographical data from the scanning probe microscopy (SPM) module for five test structures in order to obtain accurate chemical 3D maps: a polystyrene/polyvinylpyrrolidone (PS/PVP) polymer blend, a nickel-based super-alloy, a titanium carbonitride-based cermet, a reticle test structure and Mg(OH)2 nanoclusters incorporated inside a polymer matrix. The examples illustrate the potential of this combined approach to track and eliminate artefacts related to inhomogeneities of the sputter rates (caused by samples containing various materials, different phases or having a non-flat surface) and inhomogeneities of the secondary ion extraction efficiencies due to local field distortions (caused by topography with high aspect ratios). In this respect, this paper presents the measured relative sputter rates between PVP and PS as well as in between the different phases of the TiCN cermet.

Biofunctionalized prussian blue nanoparticles for multimodal molecular imaging applications

Multimodal, molecular imaging allows the visualization of biological processes at cellular, subcellular, and molecular-level resolutions using multiple, complementary imaging techniques. These imaging agents facilitate the real-time assessment of pathways and mechanisms in vivo, which enhance both diagnostic and therapeutic efficacy. This article presents the protocol for the synthesis of biofunctionalized Prussian blue nanoparticles (PB NPs)--a novel class of agents for use in multimodal, molecular imaging applications. The imaging modalities incorporated in the nanoparticles, fluorescence imaging and magnetic resonance imaging (MRI), have complementary features. The PB NPs possess a core-shell design where gadolinium and manganese ions incorporated within the interstitial spaces of the PB lattice generate MRI contrast, both in T1 and T2-weighted sequences. The PB NPs are coated with fluorescent avidin using electrostatic self-assembly, which enables fluorescence imaging. The avidin-coated nanoparticles are modified with biotinylated ligands that confer molecular targeting capabilities to the nanoparticles. The stability and toxicity of the nanoparticles are measured, as well as their MRI relaxivities. The multimodal, molecular imaging capabilities of these biofunctionalized PB NPs are then demonstrated by using them for fluorescence imaging and molecular MRI in vitro.

Iron oxide-based multifunctional nanoparticulate systems for biomedical applications: a patent review (2008 - present)

INTRODUCTION

Iron oxide nanoparticles (IO NPs) exhibit remarkable properties, including inherent magnetism, biocompatibility, high surface to volume ratio, and versatility of engineering, making them ideal candidates for a variety of clinical applications.

AREAS COVERED

The review provides an in-depth discussion on recent patents and developments related to IO NPs in Biomedicine from the last 7 years. It covers innovations in the chemical synthesis, surface coating and functionalization, and biomedical applications, including MRI and multimodal imaging, molecular imaging, cell labeling, drug delivery, hyperthermia, hyperphosphatemia, and antibacterial activity. A brief outline of the important properties of IO NPs is also presented.

EXPERT OPINION

The main focus of current research is the development of new approaches to generate high-quality IO NPs with optimal properties in terms of particle geometry, crystal structure, surface functionalities, stability, and magnetization. Among chemical synthesis methods, thermal decomposition and hydrothermal synthetics processes allow fine control of the particle properties. Plenty of coating materials have been successfully used as shells for these NPs to provide colloidal stability, even enabling the formulation of nanotheranostics for simultaneous disease diagnosis and therapy. However, long-term toxicity and pharmacokinetic studies are necessary before magnetic nanosystems can be approved for clinical use.