Photodynamic therapy of feline cutaneous squamous cell carcinoma using a newly developed liposomal photosensitizer: preliminary results concerning drug safety and efficacy

BACKGROUND: Squamous cell carcinomas are common skin tumors in cats. We investigated photodynamic therapy (PDT) using a new liposomal photosensitizer as a minimally invasive, effective treatment that can be easily performed while achieving good cosmetic results. AIM: The goal of this study was to assess and describe possible toxicities using a liposomal formulation of the photosensitizer meta-(Tetrahydroxyphenyl)Chlorin (m-THPC) and investigate if favorable pharmacokinetics translate into favorable tumor response and control. ANIMALS: Eighteen client-owned cats with 20 spontaneous cutaneous squamous cell carcinomas were included in the study. METHODS: PDT was performed using a new, liposomal formulation of the photosensitizer. Toxicity, tumor response, and tumor control were evaluated retrospectively. RESULTS: No general adverse effects were observed in cats treated with the new liposomal formulation. Mild local toxicity such as erythema and edema were seen in 15% of the patients. All cats responded to therapy, with a complete response rate of 100%. The overall 1-year control rate was 75%. The tumor recurrence rate was 20% with a median time to recurrence of 172.25 +/-87.1) days. CONCLUSIONS AND CLINICAL IMPORTANCE: A new liposomal photosensitizer was successfully used for squamous cell carcinoma in cats and was well tolerated. There were no systemic adverse effects observed with the liposomal formulation. The favorable pharmacokinetics of the liposomal drug resulted in a favorable tumor response.     

Effect of cyclin B1 antisense oligodeoxynucleotides with liposomal transfection on proliferation of HL60 cells

目的:探讨脂质体转染细胞周期素B1(cyclinB1)反义脱氧寡核苷酸(ASON)对HL60细胞增殖调控的作用。方法:用针对cyclinB1mRNA5’端编码区起始密码子(ATG/AUG)的ASON,通过脂质体导入HL60细胞共培养后,用流式细胞术(FCM)和RT-PCR分别检测cyclinB1蛋白和mRNA的表达水平,电镜和原位细胞凋亡检测法(POD)、FCM及DNA凝胶电泳法检测细胞凋亡。结果:CyclinB1ASON组与SON及空白对照组相比,ASON能特异地抑制cyclinB1蛋白及mRNA水平的表达,当ASON的浓度达到一定程度时,HL60细胞的增殖及集落形成率均明显受抑制,出现细胞凋亡,并且此作用随ASON浓度的升高而增强。结论:CyclinB1的特异ASON能封闭其蛋白及mRNA的表达水平,可剂量依赖性地抑制白血病细胞增殖,诱导细胞凋亡。     

利福平脂质体制备工艺的初步研究

用薄膜分散法制备利福平脂质体,在单因素考察的基础上进行正交试验设计,筛选出利福平脂质体的最佳制备工艺条件。结果表明,成膜后,在初次乳化温度为20℃,氯仿:PBS(v:v)为1:5,药脂比(g:g)为1:7,乳化速度为400r/min的条件下,先乳化30min,再将乳化温度升至30℃乳化30min,所制得的脂质体微球形态圆整,粒径在2.5~10μm范围内的占总数82.4%,其中5~10μm的占33.8%,包封率32.8%。     

几种辅料对紫杉醇脂质体粒径及Zeta电位的影响

[目的]探讨处方中几种辅料的加入对紫杉醇（Tax）脂质体粒径大小及Zeta电位的影响。[方法]采用薄膜分散-超声法制备Tax脂质体,利用正交设计筛选出Tax脂质体的最优处方,并测定Tax脂质体的粒径及Zeta电位。[结果]脂质体粒径及稳定性与处方中所加油酸钠等辅料有显著关系,且随着辅料量的增加,脂质体粒径变小,Zeta电位值降低,稳定性提高。[结论]油酸钠等辅料能显著降低Tax脂质体粒径及Zeta电位值。采用优选工艺制备的Tax脂质体包封率高,粒径均匀,稳定性好。     

Effect of L-arginine liposome on L-arginine transport of pulmonary artery in rats chronically exposed to hypoxia-hypercapnia

AIM: To investigate the effect of chronic hypoxia-hypercapnia and L-arginine (L-Arg) liposome on L-Arg transport in rats pulmonary artery. METHODS: Forty Sprague-Dawley rats were randomly divided into four groups, normal control group (NC), chronic hypoxia-hypercapnia group (HH), chronic hypoxia- hypercapnia group+L-Arg (HL) and chronic hypoxia-hypercapnia group+L-Arg liposome (HP). Changes in pulmonary artery L-Arg transport and pulmonary arterial microscopy were observed. RESULTS: (1) The mean pulmonary artery pressure (mPAP) and weight ratio of right ventricle to left ventricle and septum (RV/LV+S) in HH group were higher than those in NC group, and in HP group was lower than that in HH group and HL group, but there was no significant difference between HL group and HH group; (2) At 0.005 mmol/L, 0.01mmol/L, 0.02mmol/L, 0.05 mmol/L, 0.1 mmol/L and 0.2mmol/L concentration of L-Arg, the velocity of L-Arg transport in HH group was lower than that in NC group, and in HL group higher than in HH group, and in HP group was much higher than that in HH group and in HL group. (3) Light microscopy showed that vessel well area/total area (WA/TA) and media thickness of pulmonary arterioles (PAMT) were much higher in rats of HH group than those in NC group, WA/TA and PAMT in HP group were obviously improved. CONCLUSION: The above results indicated that there existed a functional disturbance in L-Arg transport of pulmonary artery in rats chronically exposed to hypoxia-hypercapnia, and it was obviously enhanced when liposome was used as L-Arg carrier. Thus, it appears that liposome-L-Arg may have clinical perspective in the treatment of chronic hypoxic pulmonary hypertension.     

Enrichment of Artemia with free methionine

Different enrichment procedures of the free amino acid (FAA) methionine were tested for Artemia nauplii. A direct enrichment protocol (methionine dissolved in the culture water) was compared with liposome enrichment protocols that varied in their membrane composition. During 16 h of direct enrichment in 5.3 mM methionine, the nauplii increased their content of free methionine between 20 and 30 times compared to the unenriched control (43.1±1.2 and 68.4±3.8 pmol·nauplius⁻¹ in two separate experiments vs. 2.4±1.0 pmol·nauplius⁻¹ in control). However, by encapsulating the identical amount of methionine into liposomes made from pure egg yolk phosphatidylcholine (PC) (>99% PC) and cholesterol, the nauplii content of free methionine reached 148.8±27.6 pmol·nauplius⁻¹, which is approximately 60 times more than in the unenriched control. Another liposome composition tested, made from crude egg yolk PC (>60% PC) and cholesterol, resulted in 90.5±4.1 pmol·nauplius⁻¹. The enriched nauplii still retained 80% of the free methionine after 8 h of incubation at conditions simulating feeding for Atlantic halibut larvae (13°C, 33.5 g·l⁻¹).

In conclusion: (1) Artemia nauplii can successfully be enriched with free methionine, (2) the high retention of free methionine in the Artemia nauplii following transfer to fish tanks shows that it is possible to offer fish larvae a feed with a high level of FAA, based on enrichment of Artemia nauplii.     

Enrichment of Artemia nauplii in PUFA, phospholipids, and water-soluble nutrients using liposomes

Different liposome formulations, includingseveral combinations of membrane composition,type of vesicle (multilamellar and largeunilamellar vesicles), preparation method, andvehiculated nutrient, have been assayed asbioencapsulation products to enrich Artemia nauplii with nutrients for feeding fish larvae.The stability of the liposome preparationsunder conditions of use as enrichment producthas been tested using water soluble fluorescentmarkers as leakage indicators. The content ofthe fatty acids and lipid classesbioencapsulated in Artemia nauplii withliposomes has been analyzed by gas and thinlayer chromatography, respectively, andcompared with other enrichment products. Theeffect of the liposome enriched Artemianauplii used as food for fish larvae has beenevaluated in sea bass cultures. Liposomes withhigh content in polyunsaturated fatty acidsleak out more than 50% of their aqueous phasein less than 2 hours, unless they arestabilized with cholesterol and formed as largeunilamellar vesicles. Such vesicles hold70% of the encapsulated material for 8 hours.Liposome enriched nauplii in this study reflectthe influence of the enrichment products,however, they are far from the commercialemulsion (Super Selco) in terms ofdocosahexaenoic acid content, except for thenauplii enriched with liposomes made of purekrill phospholipid extract by the method ofdetergent solubilization. The liposome enrichednauplii show a higher amount of polar lipids incontrast to the feed enriched with emulsions.The larvae fed liposome enriched nauplii haveonly a slightly lower docosahexaenoic acidcontent than those fed emulsion enrichednauplii. The results obtained confirm thesuitable potential use of liposomes as foodsupplement in larviculture. Problems andadvantages are discussed.     

头孢噻呋钠脂质体的毒性研究

按每千克体重1 000mg、500mg和200mg给15只小鼠腹腔注射头孢噻呋钠脂质体,7d后小鼠仍健活;再将56只小鼠随机分为7组,即头孢噻呋钠脂质体高、中、低剂量组(分别相当于临床剂量的20、10和5倍),头孢噻呋钠原料药高、中、低剂量组和生理盐水对照组,连续21d腹腔注射头孢噻呋钠脂质体和头孢噻呋钠后,进行血液学、血清生化学和组织病理学检查。小鼠血常规及生化指标经t检验后显示,头孢噻呋钠高剂量组对小鼠有明显的毒性,脂质体高剂量组也有一定毒性,但相比同剂量的原料药毒性有所降低。肝脏和肾脏病理切片结果显示,脂质体对小鼠造成的毒性影响明显比头孢噻呋钠小。本研究结果表明,经脂质体包封后的头孢噻呋钠毒性明显下降,安全性提高。     

Non-viral vector-mediated high efficiency expression of manganese superoxide dismutase gene in mouse liver

AIM: To investigate the transfection efficiency of mouse liver with non-viral vector containing manganese superoxide dismutase (Mn-SOD) gene. METHODS: The eukaryotic expression vector, gWiz/Mn-SOD, encoding human manganese superoxide dismutase was constructed. The plasmids of gWiz/Mn-SOD were mixed with cationic lipids, followed by injection into mice via branch of superior mesenteric vein, to induce Mn-SOD over-expression in murine liver detected by RT-PCR, Western blotting, SOD activity and immunohistochemical staining. RESULTS: gWiz/Mn-SOD transfection resulted in the obvious expression of exogenous Mn-SOD mRNA and protein in hepatic tissues at 8 hours after injection, and elevated mitochondria SOD activity 8.4 times in transfected hepatocytes than that in non-transfected cells at 72 hours after injection. It was showed that nearly 70% of mouse hepatocytes was obviously Mn-SOD positive after transfection. CONCLUSION: High expression efficiency of Mn-SOD gene in mouse liver is achieved safely, by injection of gWiz/Mn-SOD and cationic lipid mixture into branch of superior mesenteric vein.