Comparison of contrast imaging characteristic and acoustic pressure resistance between perfluorooctylbromide lipidic particles and C3F8 lipidic microbubbles in vitro / 中国医学影像技术

Objective: To analyze contrast imaging characteristic and resistance to acoustic pressure of perfluorooctylbromide (PFOB) lipidic microbubbles and compared with perfluoropropane (C3F8) lipidic microbubbles in vitro. Methods: PFOB lipidic particles with biotin and C3F8 lipidic microbubbles with biotin were prepared, and the stability of them were evaluated. Then the agents were used for imaging before and after adding of avidin, and the signal intensity were compared. Both PFOB particles and C3F8 microbubbles were exposed in ultrasound field of low (MI=0.28) and high (MI=0.56) ultrasound pressure levels. Their signal intensity after different exposure time (10, 20, 30 s) were compared. Results: Aggregation occurred in both two contrast agents after addition of avidin,and the particle sizes were significantly larger before (both P<0.05). The differences of particle size between the two contrast agents were significant before (t=16.225, P<0.001) and after addition of avidin (t=-5.046,P<0.001). The concentration of PFOB lipid particles did not change significantly during the observation period of stability evaluation, while C3F8 microbubbles decreased with standing time. Addition of avidin produced significant imaging enhancement in PFOB particles. However, C3F8 microbubbles manifested ultrasonic backscatter before and after adding of avidin. The signal intensity of PFOB particles were stable under low (MI=0.28) and high acoustic pressure (MI=0.56). The signal intensity of C3F8 microbubbles decreased with the prolongation of exposure time under low (MI=0.28) and high acoustic pressure (MI=0.56). Conclusion: Compared with C3F8microbubbles, PFOB particles with smaller particle size and better resistance to acoustic pressure, more suitable for targeted contrast ultrasound imaging.

Sandwich technique using a combination of perfluoropropane and silicone oil for inferior retinal detachment

We report a novel surgical sandwich technique using a combination of intraocular perfluoropropane (C3F8) and silicone oil for inferior retinal detachment (RD). After conventional pars plana vitrectomy and posterior vitreous detachment induction, fluid-gas exchange using 14% C3F8was done. This was followed by silicone oil injection using automated infusion pump to 50% fill of the vitreous cavity under direct visualization to achieve formation of two bubbles – gas bubble superiorly and silicone oil inferiorly. The patient was subsequently asked to maintain upright position. The two immiscible bubbles of C3F8and silicone oil provide tamponade to superior and inferior retina, respectively. With time, gas bubble reduces in size with a gradual superior shift of silicone oil. This novel sandwich technique achieves complete attachment of retina and reduces the risk of retinal redetachment in inferior RDs by adequately tamponading the inferior retina.

Experimental Study of Posterior Vitreous Detachment in Rabbits Induced by Hyaluronidase and Perfluoropropane(C3F8) / 医学研究杂志

Objective To evaluate the effectson experimental posterior vitreous detachment(PVD) induced by intravitrous injection of hyaluronidase and perfIuoroethane(C3F8),and whether it is safe or not.Methods Twelve rabbits(24 eyes) were divided into 3 experimental groups,the contralateral eyes in same animals served as the controls.The eyes in group A(4 eyes) and B(4 eyes) were injected with 10IU of hyaluronldase(0.2ml) and 0.2ml perfluoropropane(C3F8) respectively.The eyes in group C(4 eyes) were received vitreous injections of 10IU(0.1ml) of hyaluronldase and 0.1ml perfluoropropane(C3F8) together.All control eyes were injected with balanced salt solution(0.2ml).The ocular and fundus signs were examined for 2 following weeks and then killed for histological examination.Results Four eyes in group C showed complete separation of the vitreous cortex from the retina(PVD) by B-scan and scanning electron microscopy,and no PVD was detected in group A、B and all control eyes.No evidence of retinal toxicity was revealed by light or transmisson electron microscopy in all eyes.Conclusion Vitreous injection of hyaluronidase combined with perfluoropropane(C3F8),as a safety method,can induce posterior vitreous detachment after 2 weeks.

Methodology and clinical application of left heart contrast echocardiagraphy with perfluoropropane-albumin microsphere / 中国临床药理学与治疗学

0.05 ). The average enhancement rate of LV endocardial border was 96.6 %. The myocardial contrast agent perfusions of left ventricular walls were clearly visualized in 30 patients. CONCLUSION: Clinical application of intravenous left heart contrast echocardiagraphy with perfluoropropane-albumin microsphere is feasibility and effective.

The Effect of Subconjunctival Retention of Perfluoropropane Gas on the Success Rates of Trabeculectomy in Rabbits

PURPOSE: This study was aimed to evaluate the effect of subconjunctival retention of perfluoropropane gas on the success rates in trabeculectomized rabbits. METHODS: Fifthteen white rabbits were trabeculectomized by fornix-base conjunctival flap, full thickness sclerotomy and iridectomy. The right eye was control and the left eye was injected with 0.2 ml perfluoropropane gas(C3F8) into subconjunctival space through the 30 guage long needle. Each rabbit was examined for bleb morphology under slit-lamp microscope and measured for intraocular pressure by tonopen at preoperative, postoperative 3 days, 1 week, 2 weeks, 4 weeks, and 6 weeks. The results were analyzed by Wilcoxon rank sum test in SAS release 6.12 program. RESULTS: Mean gas retention time was 15+/-2 days. Intraocular pressure measured at postoerpative 2 weeks was statistically significantly lower in gas injected group than control group. At postoperative 2 weeks, fibrovascularization was more prominent in control group than gas injected group. Fibroblast proliferation and collagen tissue formation were more prominent in control group than gas injected group at postoperative 6 weeks. CONCLUSIONS: Subconjunctival perfluoropropane gas(C3F8) bubbles, via "spacer" effect, aid the maintenance of filtering blebs in the early postoperative period. This technique may be useful in augmenting or salvaging blebs at high risk of failure.

Vitreous surgery for macular holes / 眼科新进展

Objective　To review the anatomic and visual outcomes of a series of patients with macular holes who underwent vitreous surgery without adjunctive therapy.Methods　We performed a retrospective review of 16 patients who underwent vitrectomy, fluid-gas exchange and perflu oropropane(C3 F8) gas temponade for 14 eyes with idiopathic and 2 eyes with traumatic macular holes.Results　Anatomical closure of the macular holes was achieved in 15(93%) of 16 eyes with an average follow-up of 7 months. Only one eye needed performing second surgery. Three(19%) eyes achieved postoperative visual acuity of 0.4, four (25%)eyes 0.2～0.3,and nine(56%)eyes 0.1 or worse. Conclusions　Vitreous surgery without adjunctive therapy with intraocular gas tamponade and postoperative posturing is a well tolerated and effective intervention for idiopathic or some traumatic macular holes. Anatomical closure of the macular hole is associated with a significant improvement in visual acuity in most eyes.

Induction of vitreolysis and vitreous detachment with hyaluronidase and perfluoropropane gas

To simulate the posterior vitreous detachment (PVD) in the rabbit, 1 IU hyaluronidase and/or 0.2 ml of perfluoropropane gas was intravitreally injected. Ophthalmoscopic, light microscopic examination prepared by cryotechnique, electron microscopic examination, and electroretinogram were done on the 3rd and 28th postoperative days. As a result, the eyes undergone simultaneous intravitreal injection of 1 IU hyaluronidase and 0.2 ml perfluoropropane gas showed membranous structure split from the internal limiting membrane of the superior retina in 3 days after injection. The eyes also demonstrated membranous structure separated from the superior retina after 28 days, simulating vitreous detachment. On the contrary, neither agent alone induced vitreous detachment. No toxic retinal changes associated with simultaneous intravitreal injection of 1 IU hyaluronidase and 0.2 ml perfluoropropane gas were observed. Therefore, with a future support by histologic examination other than cryotechnique and by immunohistochemical analysis, the simultaneous intravitreal injection of perfluoropropane gas and hyaluronidase would be a promising method to induce vitreous detachment in non-vitrectomized eye.

Improved left ventricular endocardial border echo resolution by perfluoropropane-albumin microsphere injection: a multiple center stage Ⅲ clinical study / 中华超声影像学杂志

0.05 ). After once injection both observers considered the number of clearly recognized endocardial border segments increased significantly. The number evaluated by observers A increased from 2.68 ? 0.95 to 5.99 ? 0.10 while from 2.82 ? 1.03 to 5.99 ? 0.11 by observers B( P 0.05 ). The average contrast enhancement rate of LV endocardial border was 99.7 %. Perfluoropropane-albumin microsphere injection had no significant effection on vital signs such as blood prssure, heart rate and respiration. Electrocardiogram didn′t change markedly and the variance of the laboratory findings like blood and urine routine examination, hepatic and renal function was in normal range. Only one case( 0.33 %) had slight side-effects who suffered from mild nausea and diarrhea, which suggested the clinical safety of this contrast agent. Conclusions Perfluoropropane-albumin microsphere injection could enhance the resolution of LV endocardial borders and make the judgement of regional myocardial movement easier. It has little side-effects and will be appropriate for clinical use.