In Vivo Near-Infrared Imaging of Fibrin Deposition in Thromboembolic Stroke in Mice

imaging of activated factor XIII (FXIIIa), an important mediator of thrombosis or fibrinolytic resistance. The present study was to investigate the fibrin deposition in a thromboembolic stroke mice model by FXIIIa–targeted near-infrared fluorescence (NIRF) imaging., which were correlated with histology after animal euthanasia. NIRF images and lesion volume.Non-invasive detection of fibrin deposition in ischemic mouse brain using NIRF imaging is feasible and this technique may provide an in vivo experimental tool in studying the role of fibrin in stroke

Fetal ocular development in the second trimester of pregnancy documented by 7.0 T postmortem Magnetic Resonance Imaging.

Few investigators have analyzed fetal ocular growth with Magnetic Resonance Imaging (MRI) of high magnetic strength. Our purpose is to obtain normative biometrics for fetal ocular development in the second trimester of pregnancy. Sixty specimens with a gestational age (GA) of 12-23 weeks were scanned using a 7.0 T MRI scanner. The linear interocular and binocular distances (IOD and BOD, respectively), globe diameter (GD) and lens diameter (LD) were measured on the transverse section of the largest diameter of the eyeballs. The three dimensional (3D) visualization model of the eyeball was reconstructed with Amira software. Then, the globe and lens volumes (GV and LV, respectively) were obtained. All the measurements were plotted as a function of GA. The fetal ocular structures in the second trimester of pregnancy could be clearly delineated on 7.0 T postmortem MRI images. All the linear measurements logarithmically increased with GA, while, the volumetric measurements linearly increased with GA. Postmortem MRI of high magnetic strength can clearly document fetal ocular growth in the second trimester of pregnancy. These quantitative data may be a valuable reference for the assessment of normal fetal eyeball development in clinical settings and may be considered a supplement to anatomical investigations

Resting-State Functional Connectivity Analyses: Brain Functional Reorganization in a Rat Model of Postherpetic Neuralgia

Postherpetic neuralgia (PHN) is a chronic neuropathic pain syndrome, similar to other chronic pains, the mechanisms of which are not fully understood. To further understand the neural mechanism of this chronic pain and its transition, we performed functional magnetic resonance imaging (fMRI) scans on PHN rat models. Twelve PHN rat models were established by intraperitoneal injection of resiniferatoxin, with an additional 12 rats serving as controls. Nociceptive behavioral tests were performed on these rats and fMRI scans were performed on days 7 and 14 after modeling. Functional connection (FC) analysis was used to investigate the brain FC alterations associated with chronic pain in PHN rats, with the anterior cingulate cortex (ACC) as a seed. Nociceptive behavioral tests showed that PHN rats presented symptoms similar to those of PHN patients. FC analysis showed that compared to the control group, the PHN group showed different FC patterns on days 7 and 14. As can be seen, the brain FC alterations in the rat model of PHN changed dynamically, shifting from brain regions processing sensory information to regions processing emotions and motives

Precise Study on Size-Dependent Properties of Magnetic Iron Oxide Nanoparticles for In Vivo Magnetic Resonance Imaging

Developing a biocompatible contrast agent with high stability and favorable magnetism for sensitive detection of malignant tumors using magnetic resonance imaging (MRI) remains a great demand in clinical. Nowadays, the fine control of magnetic iron oxide nanoparticle (MION) sizes from a few nanometers to dozens of nanometers can be realized through a thermal decomposition method of iron precursors. This progress allows us to research accurately on the size dependence of magnetic properties of MION, involving saturation magnetization (Ms), specific absorption rate (SAR), and relaxivity. Here, we synthesized MION in a size range between 14 and 26 nm and modified them with DSPE-PEG2000 for biomedical use. The magnetic properties of PEGylated MION increased monotonically with MION size, while the nonspecific uptake of MION also enhanced with size through cell experiments. The MION with the size of 22 nm as a T2-weighted contrast agent presented the best contrast-enhancing effect comparing with other sizes in vivo MRI of murine tumor. Therefore, the MION of 22 nm may have potential to serve as an ideal MRI contrast agent for tumor detection

Representative NIRF imaging of different groups 24 h after infusion of the fluorescent probe.

<p>In vivo NIRF imaging (A, Left) or ex vivo NIRF imaging of the mouse brains removed from the skull (A, Right) showed no difference between the hemispheres in sham-operated mice injected with the A15 probe. The rectangular boxes represented the ROIs placed over the right and left hemisphere. There was only slight increase of fluorescence intensities in the injected hemisphere compared with the contralateral side in MCAO mice injected with the C15 control probe (in vivo NIRF imaging, B, Left; and ex vivo NIRF imaging, B, Right). Strong fluorescence was seen over the ipsilateral side of MCAO mice injected with the A15 probe shown by in vivo NIRF imaging (C, Left) or ex vivo NIRF imaging (C, Right). The images were normalized on the color scaling bar. Target-to-background ratios (TBRs) were calculated from ROI analyses of noninvasive NIRF images in different groups as shown in Fig D. Only the MCAO mice receiving the A15 probe showed significantly higher TBRs (*P<0.05 versus SHAM). Bar in (A–C) = 5 mm.</p

Fluorescence images of brain sections showed the ipsilateral cortex of MCAO mice at 1, 8, 24 and 96 hours after intravenous injection of A15.

<p>The green signals showed the staining with FITC-labeled antibodies against fibrin (A), and the red signals (NIRF channel) displayed the distribution of the injected Cy5.5-labeled probes (B). The embedded scatter gram in the upper left corner of each image (C) showed good overlap of colocalization analysis (C). (40×, Bar = 50 µm).</p

Time courses of in vivo NIRF imaging of MCAO mice injected with A15 at 6 h, 8 h, 20 h and 96 h (A).

<p>Quantification of target-to-background ratios (TBRs) at different time points (From 0–96 h post injection of A15) was shown in B. The group that were significantly different were compared with 0 h (TBRs = 1). (*P<0.05 versus time 0).</p

Quantitative analysis of targeted signals from in vivo and ex vivo NIRF imaging of the mouse brains removed from the skull and lesion volume of T₂WI (%HLV^e).

<p>The targeted signals of in vivo and ex vivo NIRF images are separated from background signals by multispectral imaging technology (A). ROI was selected by threshold segmentation (B). <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0030262#pone-0030262-g005" target="_blank">Fig. 5C</a> shows T₂WI of MCAO mice 24 h after injection of A15, and area of hyperintensity delineates ischemia lesion. A significant correlation is observed between the total targeted signal values of in vivo NIRF images (R² = 0.526, P<0.05) and the total targeted signal values of ex vivo NIRF images of MCAO mice injected with the A15 probe (D, Left). A significant correlation is observed between the value of total targeted signal from in vivo NIRF imaging (R² = 0.483, P<0.05) or from ex vivo NIRF imaging (R² = 0.843, P<0.05) and lesion volume of T2WI (%HLV^e) (D, Middle, Right). Bar in (A–D) = 5 mm.</p