endinopathy, a common soft tissue disorder in tendons and their insertions, features hypercellularity, a disoriented fiber arrangement, and neovascularization on histologic examinations. 1,2 Healthy tendons are hypovascular in architecture, receiving a blood supply from the extrinsic system through the paratendon or synovial sheath and the intrinsic system at the myotendinous or osteotendinous junction. 3 Although temporary hyperemia is a normal response after exercise or a healing process on injury, 4,5 persistent hypervascularity elicits unresolved pain and possibly alters the mechanical properties of tendons. 6 Sclerosing Ke-Vin Chang, MD, Chueh-Hung Wu, MD, Yu-Hui Ding, BD, Hsiu-Yu Shen, MD, Tyng-Guey Wang, MD, Wen-Shiang Chen, MD, PhD Received September 30, 2011, ORIGINAL RESEARCHObjectives-The purpose of this study was to investigate the ability of contrastenhanced sonography in staging and grading hypervascularity in tendinopathic tissues by using a rabbit model.Methods-Fourteen rabbits were injected with 100 and 50 μL of collagenase in their left and right Achilles tendons, respectively. The vascularity was assessed by non-contrastenhanced and contrast-enhanced power Doppler sonography on day 0 (baseline) and days 1, 7, and 14 after collagenase injections. Color pixels within targeted areas were plotted according to time and analyzed by a curve-fitting method.Results-Non-contrast-enhanced power Doppler sonography failed to differentiate vascularity at various stages or between bilateral tendons, whereas contrast-enhanced sonography showed that the peak color pixel amount reached its maximum on day 1 and declined over time in tendons treated with 100 μL of collagenase. A similar trend was observed in tendons receiving 50 μL of collagenase. For comparisons between bilateral tendons, higher vascularity was detected in those treated with more collagenase on day 1 or 7. Time-intensity curve analysis revealed rapid microbubble replenishment in both tendons during their initial phase after collagenase injections.Conclusions-Contrast-enhanced sonography discriminated the vascularity of various injury grades at different time points after collagenase injections. Time-intensity curve analysis detailed the hemodynamics in tendinopathic tissues, which helped differentiate vascularity in acute inflammatory from later degenerative phases.
Discrepancies between hyperecho-predicted necrosed volume in ultrasound (US) images and the actual size of a thermal lesion might cause incomplete ablation or damage normal structures during high intensity focused US (HIFU) ablations. A novel dual-frequency sonication procedure is proposed to reduce this discrepancy. HIFU transducers of either 1 or 3.5 MHz were applied to transparent tissue-mimicking phantoms and ex vivo bovine liver samples. A diagnostic probe and a charge-coupled device (CCD) camera were used to record lesion formation in real time, allowing for comparison of the sizes of the hyperechoes in US images and the protein denaturing area on optical images. Bovine liver specimens were segmented to reveal the lesion's terminal sizes. Differences between actual lesion volume and hyperechoes in US images were demonstrated to be dependent on acoustic frequency and intensity. At a low frequency (1 MHz), the hyperechoes appeared to be larger than the actual volume, but the difference decreased with the duration of ablation. In contrast, at a high frequency (3.5 MHz), the hyperechoes were smaller for ablations lasting longer than 10 s. Moreover, given certain low-intensity conditions, lesions were formed without detectable hyperechoes (3.5 MHz), or hyperechoes appeared before a visible lesion was formed (1 MHz). Dual frequency sonications (low frequency followed by high frequency) produce more stable and larger lesions, and with less position shift, which might be useful for designing future ablation strategies.
Tropidoneis maxima is a marine diatom with a rapid growth rate that produces high levels of lipids. To explore whether the lipid content could be further enhanced, cultures were first incubated under optimal conditions and then stressed under low temperature (10°C), a high light intensity level (80 μmol/m2·s), and the two factors together (interaction treatment). The results indicated that high light intensity and the temperature‐light interaction exhibited greater impacts on lipid synthesis of T. maxima than low temperature. The two stress treatments increased lipid content by 17.16% and 16.6% compared to the control. In particular, higher biomass concentration was obtained with high light intensity (1.082 g L−1) and low temperature (1.026 g L−1). Moreover, high light intensity (9.06%) and interaction (10.3%) treatments yielded lower starch content compared to low temperature (14.27%) at the end of the stress culture. After 3 days of stress culture, the high light intensity treatment resulted in a 97.01% increase in cell wall thickness and an 18.46% decrease in cell diameter. The results suggest that high light intensity stress on T. maxima would open a new approach to cost‐effective biolipid production.
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