Near-infrared fluorescence imaging of mouse myocardial microvascular endothelium using Cy5.5-lectin conjugate.

Cy5.5-lectin, a non-toxic conjugate, combines the benefits of near-infrared (NIR) imaging, such as significant reduction of background fluorescence and increased tissue depth penetration, with its affinity for vascular endothelial cells. When compared to endothelial staining methods using FITC-lectin and ICAM2 antibodies, Cy5.5-lectin was confirmed to specifically bind endothelial cells and produce a fluorescence signal both in real-time and post-infusion. Ex-vivo experiments with isolated hearts demonstrated that binding was limited to perfused areas of the myocardium. With mouse in-vivo tail-vein injections, other organs such as the liver, spleen, and kidney were also stained and yielded similar quality images of the heart.

Chronic care and monitoring of woodchucks (Marmota monax) during repeated magnetic resonance imaging of the liver.

We monitored the development of hepatocellular carcinoma due to chronic infection with woodchuck hepatitis virus by using monthly serum samples, physical examination, and magnetic resonance imaging. The same woodchucks can be imaged repeatedly over a 1-y period by allowing the animals to recover after each experiment, thus reducing the number of animals required without compromising the quality of the data obtained. Age- and sex-matched uninfected control (n = 5) and chronically infected (n = 5) woodchucks were group-housed according to sex and infection status. Woodchucks were anaesthetized using an inhalation anesthetic (isoflurane) without premedication. During imaging, we regularly monitored heart rate, body temperature, and respiration. Tumor growth was observed using MRI, whereas the extent of hepatocyte injury was followed using serum liver enzymes. Elevated serum gamma glutamyltransferase and aspartate aminotransferase levels indicated hepatocyte injury due to tumor growth. On magnetic resonance images, the liver should appear as a well-defined, homogenous organ with defined regions of hyperintensities from larger blood vessels. Within tumor nodules, the liver appeared irregularly shaped, having heterogeneous intensity from unregulated cellular proliferation. Changes in tumor size can be monitored by imaging infected woodchucks on a regular basis. Using the imaging techniques we describe, the development of hepatocellular carcinoma can be visualized using magnetic resonance imaging, correlated to serum tests, and compared with the results from uninfected control woodchucks, thereby improving the understanding of the disease progress.

Functional MRI of the rat lumbar spinal cord involving painful stimulation and the effect of peripheral joint mobilization.

PURPOSE: To examine neuronal activation in the spinal cord due to secondary hyperalgesia resulting from intrajoint capsaicin injection, and the effect of physiotherapy manipulation, using functional magnetic resonance imaging (fMRI), in alpha-chloralose anesthetized rats. MATERIALS AND METHODS: FMRI of the rat lumbar spinal cord was performed at 9.4 Tesla. Stimuli included injection of 25 microL of capsaicin (128 microg/mL in 7.5% dimethyl sulfoxide [DMSO]) into the right forepaw or 75 microL into the right ankle joint followed by a light touch stimulus, with and without physiotherapy manipulation. RESULTS: Activation of pain areas of the spinal cord (dorsal horn) was found in all animals after injection of capsaicin into the plantar surface of the rat hindpaw and ankle joint. Overlay maps depicting activations and deactivations showed significant reproducibility between experiments. Greater overlay of activations were observed for intrajoint compared to intradermal capsaicin injection. The distribution of activations after stimulation of the hindpaw using a light touch stimulus was somewhat more varied; activation of the dorsal horn was evident, with greater overlap resulting when joint mobilization was not performed. CONCLUSION: Results suggest a trend toward decreased areas of activation in the spinal cord associated with pain, as a result of hyperalgesia, following physiotherapy joint mobilization.

Functional MRI involving painful stimulation of the ankle and the effect of physiotherapy joint mobilization.

We examined whether cerebral activation due to secondary hyperalgesia resulting from intrajoint capsaicin injection could be detected using functional magnetic resonance imaging (fMRI) in alpha-chloralose anesthetized rats. We also examined whether we could detect analgesic changes in the central nervous system response to pain as a result of physiotherapy joint manipulation. Robust activation of areas of the brain known to be associated with the processing of pain, namely the anterior cingulate (bilateral), frontal cortex (bilateral) and sensory motor cortex (contralateral), was found in all animals following injection of 25 microl of capsaicin (128 microg/ml in 7.5% DMSO) into the plantar surface of the rat hindpaw (n = 7) and 75 microL into the ankle joint (n = 13). Significantly greater activation was observed when capsaicin was injected into the plantar surface of the hindpaw compared to the ankle joint. Mechanical allodynia and secondary hyperalgesia following capsaicin injection into the ankle joint also resulted in activation of the same brain regions. Trends toward decreased areas of activation in brain regions associated with pain in animals following physiotherapy joint mobilization were observed.