Multimodal imaging and photothermal/chemotherapy in vitro study of peptide-mediated network engineering paclitaxel nanoparticles loaded with metal polyphenols / 中华超声影像学杂志

Objective:To prepare a phase-change lipid nanoparticle modified by tumor homing membrane-penetrating peptide (tLyP-1) and carrying paclitaxel (PTX) engineered by metal polyphenol network (TA-Fe 3+ ), and evaluate the therapeutic effects of tumor targeting, ultrasound/photoacoustic imaging and photothermal combined chemotherapy in vitro. Methods:Phase-change lipid nanoparticles (t-P@TFP) with TA-Fe 3+ engineered PTX mediated by tLyP-1 were prepared by solvent replacement method, thin film hydration method and double emulsification method. Its detection and characterization, in vitro targeting ability, photothermal conversion ability, in vitro photoacoustic and ultrasonic imaging ability, CCK-8 method, cell live and death double staining method and flow cytometry method were used to detect the safety of nanoparticles and the killing effects of different nanoparticles on 4T1 cells. Results:t-P@TFP nanoparticles were successfully prepared. Transmission electron microscopy showed that the nanoparticles were spherical with uniform shape and size, with a particle size of (209.8±1.56)nm and a potential of (-25.9±1.36)mV. Laser confocal scanning microscopy showed that t-P@TFP nanoparticles could gather around 4T1 cells in a targeted manner. It had an efficient photothermal conversion effect, and nanoparticles could quickly become microbubbles after being irradiated by near-infrared laser, which enhanced the in vitro ultrasonic imaging effect; The photoacoustic signal of nanoparticles increased with the increase of concentration. CCK-8 method, double staining of living and dead cells and flow cytometry showed that t-P@TFP combined photothermal chemotherapy had the best anti-tumor effect. Conclusions:t-P@TFP nanoparticles are successfully prepared. The nanoparticles have good targeting ability for photoacoustic and ultrasonic imaging and have good photothermal effect, killing breast cancer cells, which is expected to realize the integration of diagnosis and treatment.

Effects of different position during high frequency oscillatory ventilation on oxygenation and hemodynamics of dogs with severe smoke inhalation injury / 中华烧伤杂志

<p><b>OBJECTIVE</b>To study the effects of high frequency oscillatory ventilation (HFOV) with different position on oxygenation and hemodynamics of dogs with severe smoke inhalation injury.</p><p><b>METHODS</b>After being treated with conventional mechanical ventilation, 12 dogs were inflicted with severe smoke inhalation injury and treated by HFOV for 30 min. They were divided into HFOV+prone positioning (PP) group and HFOV+supine positioning (SP) group according to the random number table, with 6 dogs in each group. They received HFOV with corresponding position for 8 hours respectively.</p><p><b>RESULTS</b>of blood gas analysis (pH, PaO₂ and PaCO₂ levels), oxygen index (OI) and hemodynamic parameters [heart rate, mean arterial pressure (MAP), and cardiac output (CO)] were recorded or calculated before injury, immediately after injury, and at post ventilation hour (PVH) 2, 4, 6, 8. Data were processed with analysis of variance of repeated measurement, and LSD- t test.</p><p><b>RESULTS</b>(1) At PVH 8, pH value of dogs in group HFOV+PP was significantly higher than that in group HFOV+SP (t = 3.0571, P < 0.05). Compared with those observed immediately after injury, except for group HFOV+SP at PVH 2 and 4 (with t values respectively 2.066 5 and 1.440 7, P values all above 0.05), the pH values in both groups at other treatment time points were decreased (with t values from 2.449 5 to 3.985 3, P < 0.05 or P < 0.01). At PVH 2, 4, 8, the PaO₂ levels in group HFOV+PP [(131 ± 26), (150 ± 40), (112 ± 30) mmHg, 1 mmHg = 0.133 kPa] were higher than those in group HFOV+SP [(81 ± 15), (96 ± 5), (83 ± 6) mmHg, with t values from 2.366 4 to 4.083 5, P < 0.05 or P < 0.01]. The PaO₂ levels in both groups from PVH 2 to PVH 8 were increased, compared with those observed immediately after injury [(55 ± 15) mmHg in group HFOV+SP and (48 ± 11) mmHg in group HFOV+PP, with t values from 2.473 6 to 7.2310, P < 0.05 or P < 0.01]. No statistically significant differences were observed in PaCO₂ level at each time point between two groups (with t values from 0.661 0 to 2.141 9, P values all above 0.05). No statistically significant differences were observed in PaCO₂ levels from PVH 2 to PVH 8 compared with those observed immediately after injury in both groups (with t values from 0.126 2 to 1.768 3, P values all above 0.05). (2) The OI values in group HFOV+SP were significantly higher than those in group HFOV+PP from PVH 2 to PVH 8 (with t values from 3.091 9 to 3.791 6, P < 0.05 or P < 0.01). The OI values in both groups from PVH 2 to PVH 8 were significantly decreased, compared with those observed immediately after injury (with t values from 2.702 0 to 5.969 3, P < 0.05 or P < 0.01). (3) At PVH 6 and PVH 8, heart rate in group HFOV+PP was significantly higher than that in group HFOV+SP (with t values respectively 4.255 9 and 4.765 9, P values both below 0.01). Compared with that observed immediately after injury, heart rate in group HFOV+PP was significantly decreased (with t values from 3.006 2 to 5.135 5, P < 0.05 or P < 0.01) except for PVH 2 (t = 1.938 2, P > 0.05). However, there was no statistical significant difference at each treatment time point in group HFOV+PP (with t values from 0.786 5 to 1.525 8, P values all above 0.05). There was no statistically significant difference in MAP between two groups at each time point (with t values from 0.045 8 to 1.783 4, P values all above 0.05). Compared with that observed immediately after injury, MAP in group HFOV+SP was significantly decreased at PVH 8 (t = 2.368 3, P < 0.05); MAP in group HFOV+PP was significantly decreased at PVH 2 (t = 3.580 1, P < 0.01). At PVH 2 and 4, the CO values in group HFOV+SP were significantly higher than those in group HFOV+PP (with t values respectively 2.310 3 and 4.526 5, P values both below 0.01). Except for group HFOV+SP at PVH 2 (t = 1.294 1, P > 0.05), CO values at other treatment time points in both groups were significantly lower than that observed immediately after injury (with t values from 2.247 0 to 4.067 8, P < 0.05 or P < 0.01).</p><p><b>CONCLUSIONS</b>HFOV+ PP can improve oxygenation with no obvious CO₂ retention or adverse effect on hemodynamic parameters of dogs with severe smoke inhalation injury. Therefore, it is recommended for clinical application.</p>

Chest radiological analysis of SARS in children / 中华放射学杂志

Objective To discuss the radiological characteristics and improve the diagnostic ability of SARS in children. Methods The clinical data and X-ray findings of 35 SARS cases who hospitalized during Jan, 2003～Apr, 2003 were retrospectively analyzed. Results Chest X-ray features were as follows: massive consolidation (27 cases, 77.1%), pulmonary interstitial infiltration (6 cases, 17.1%), and mixed pattern (2 cases, 5.7%). There were two patients with emphysema, but no patient with lung abscess or pleural lesion. The radiological dynamic changes showed that the lesions of lung appeared early, the severest period was between the fifth day and the seventh day, the X-ray findings were not consistent with physical sign, and the absorption of lesion was slower than the clinical process. Conclusion There are some certain radiographic characteristic in children with SARS. A correct diagnosis can be made by closely combining the X-ray findings with clinical and laboratory results.