青蒿素纳米脂质体的制备工艺研究

研究旨在优化青蒿素纳米脂质体制备工艺,以制备粒径较小、包封率较高的青蒿素纳米脂质体。试验采用薄膜分散法、逆向蒸发法、乙醇注入法和改良乙醇注入法制备青蒿素纳米脂质体,优选改良乙醇注入法;以磷脂与胆固醇的质量比、药物与磷脂的质量比、水相体积和超声时间为考察因素,以包封率为评价指标,通过单因素试验和Box-Benhnken响应面法优化脂质体制备工艺,并对纳米脂质体进行表征。结果显示,改良乙醇注入法制备青蒿素纳米脂质体的最佳工艺为青蒿素与磷脂的质量比为1∶14.53,磷脂与胆固醇的质量比为5.42∶1,生理盐水体积9.74 mL （此时磷脂质量为250 mg）。此条件下制备的青蒿素纳米脂质体形态呈双层球形,包封率为68.57%,平均粒径为195.13 nm,PDI为0.19,Zeta电位为-12.10 mV。     

辣蓼黄酮长循环纳米脂质体的制备

研究旨在优化辣蓼黄酮长循环纳米脂质体制备条件。试验首先以包封率为评价指标,筛选辣蓼黄酮长循环纳米脂质体制备方法。确定改良乙醇注入法后,采用单因素试验考察磷胆比、药脂比、生理盐水体积、超声时间、表面活性剂用量因素对包封率的影响;再通过Box-Behnken响应面法进行3因素3水平优化,选取磷胆比、药脂比、生理盐水体积等3个因素进一步优化;确定最佳的脂质体制备条件后,通过后插入法将DSPEMPEG 2000插入辣蓼黄酮纳米脂质体上,制成辣蓼黄酮长循环纳米脂质体并进行表征。结果显示,改良乙醇注入法制备辣蓼黄酮长循环纳米脂质体最优条件是：磷胆比（质量比） 6.8∶1、药脂比（质量比） 1∶10.3、生理盐水体积9.5 mL。选择摩尔比为5%的DSPE-MPEG 2000制备长循环纳米脂质体,在最优条件下制备的辣蓼黄酮长循环纳米脂质体平均包封率为（72.60±2.44）%,脂质体粒径为（80.93±0.30） nm,多分散性指数（PDI）为0.14±0.01,Zeta电位（-1.70±0.29） mV。     

槲皮素纳米粒的制备及其体外评价

为了考察槲皮素纳米粒的体外特性,试验采用薄膜分散法制备了槲皮素纳米粒,采用透射电镜、X射线衍射法(XRD)对其进行表征,采用动态膜透析法考察载药纳米粒的体外释药特性。结果表明:薄膜分散法制备的纳米粒呈球形或类球形,平均粒径为(51.5±5.9)nm,平均包封率为(89.13±3.97)%,平均载药量为(2.87±1.91)%;槲皮素以无定型状态或分子状态分散在纳米粒中;槲皮素纳米粒体外释放具有明显的缓释作用。说明槲皮素纳米粒制备工艺简单,其粒径、包封率、载药量可控,具有缓释作用。     

黄藤素柔性纳米脂质体水凝胶贴剂的制备及体外透皮给药研究

为奶牛乳房炎的治疗提供了一种新型高效的透皮给药制剂,并考察其体外透皮给药的行为特点。采用薄膜分散法制备黄藤素柔性纳米脂质体(PFL),高效液相色谱仪(HPLC)测定包封率,透射电镜(TEM)观察PFL的结构、激光粒度仪(LPSA)测定PFL的粒径和表面Zeta电位;然后将PFL制备成水凝胶贴剂(PFL-HP),并采用立式双室扩散池考察PFL-HP体外透皮给药的行为特点,并同药物水凝胶贴剂(P-HP)与加入5%氮酮的水凝胶贴剂(P-A-HP)进行对照。结果表明,PFL对黄藤素的包封率为(79±2.23)%,PFL为圆球形层状囊泡结构,粒径为(190±24)nm,Zeta电位为(-54±2.65)m V;PFL-HP膏体柔软、膏面平整光洁,黏附性良好可48 h黏附于奶牛乳房而不脱落;24 h时,PFL-HP的药物累积透过量是P-HP与P-A-HP的2.12倍(t-test,P0.05)与1.13倍(t-test,P0.05),同时,PFL-HP组中药物在皮肤组织的滞留量(即"储库效应")也高于P-HP与P-A-HP(t-test,P0.05)。黄藤素柔性纳米脂质体水凝胶贴剂(PFL-HP)药物透皮吸收效率高、黏附性良好、使用方便,奶牛对其具有良好的依从性。PFL-HP可作为治疗奶牛乳房炎的一种新型高效透皮给药制剂。     

马尾藻多糖纳米脂质体对人工感染鸡白痢沙门氏菌预防试验

目的：研究马尾藻多糖纳米脂质体对鸡白痢的预防效果。方法：采用人工感染鸡白痢沙门氏菌病症模型,分别加马尾藻多糖纳米脂质体100、200、400 mg/kg于人工感染雏鸡,观察马尾藻多糖纳米脂质体对鸡白痢的预防作用。结果：马尾藻多糖纳米脂质体能降低鸡人工感染沙门氏菌的死亡率。结论：马尾藻多糖纳米脂质体对鸡白痢有一定的预防作用。     

转移因子纳米脂质体的制备及其体内吸收情况的观察

采用逆相蒸发法制备转移因子脂质体（TFL），以包封率为优化指标，正交试验优选最佳配方；电镜下观察TFL形态，紫外法检测包封率和渗透率；并用电镜观察用药后小白鼠小肠的吸收情况。结果，确定的最佳制备工艺为：卵磷脂与胆固醇的摩尔比为2：1，转移因子（TF）浓度为6mg／mL，吐温-80为1mL，有机相与水相的体积比为4：1。电镜下大部分TFL粒径小于100nm，分布均匀，包封率高达49．5％，4.5个月后的渗透率为52．4％。采用优选工艺制备的转移因子纳米脂质体具有一定的稳定性，而且小肠内吸收良好。     

阿莫西林脂质体的制备及质量评价

采用薄膜分散法制备阿莫西林脂质体,以粒径和包封率为指标评价其质量.前期以正交设计优化筛选出最佳制备工艺,以最优工艺制备阿莫西林脂质体,测定其平均粒径和包封率.实验所制得的脂质体的平均粒径为114.6 nm,包封率为64.89％.结果表明,采用薄膜分散法制备阿莫西林脂质体的方法可行,阿莫西林脂质体的制备为兽药新剂型的研究与应用提供了有价值的参考.     

Box-behnken响应面法优化茶树精油纳米脂质体的制备及其表征与抑菌活性分析

筛选茶树精油纳米脂质体(TTONL)最佳制备工艺并对其进行表征和抑菌效果评价。采用薄膜水化超声法制备TTONL,Box-behnken响应面法优化TTONL的制备最佳条件，并对其性能和抑菌效果进行测定。结果显示，TTONL的最佳制备条件：卵磷脂和胆固醇质量比3.7∶1,茶树精油(tea tree oil, TTO)浓度0.5%,水化介质pH 7.4,包封率为(80.31±0.56)%。透射电镜显示TTONL形状接近球形，平均粒径为(227.8±25.3) nm。红外光谱结果显示TTO被包合到脂质体内腔中。对TTONL的缓释性和稳定性进行考察，TTONL中的药物能在pH 7.4条件下缓慢释放，在42 d内，4℃环境下TTONL的粒径和多散性指数(PDI)变化都不大。体外抑菌试验表明TTONL对大肠杆菌具有很好的抑制和杀灭效果，最低抑菌浓度(MIC)为0.08%,最低杀菌浓度(MBC)为0.16%,较TTO原液相比降低；TTONL的抑菌活性与浓度呈正相关，1 MIC的TTONL处理大肠杆菌后，在8 h已完全达到杀菌效果。经优化后的TTONL形态表征良好，稳定性较好，缓释效果明显，对大肠杆菌...     

普多沙星凝胶剂的制备及质量控制

普多沙星是一种专用于犬、猫细菌感染的新型动物专用氟喹诺酮类药物,以普多沙星为主药,以羧甲基纤维素纳、甘油、丙二醇的用量及pH为考察因素,以凝胶剂的涂展性、均匀度、离心性为指标进行综合评分,筛选优化处方,制备普多沙星凝胶剂,并对其进行质量控制研究。采用紫外分光光度法测定普多沙星的含量。优化处方为CMC-Na 50g/L、甘油160mL/L、丙二醇200mL/L、pH 6.7。检测波长282nm,普多沙星在2μg/mL～10μg/mL与吸收度呈良好的线性关系,R2=0.999 7,平均回收率为98.02%,RSD=0.15%(n=5),所制得的凝胶稳定性良好,无变化。表明该凝胶剂制备方法简单,稳定性好,质量可控,各项指标符合凝胶剂的质量标准。     

奥比沙星对水生生物病原菌的体外抑菌作用

采用纸片法和二倍试管稀释法研究了动物专用药物奥比沙星对6种水生生物病原菌(大肠埃希菌、嗜水气单胞菌、产酸克雷伯菌、鱼害黏球菌、荧光假单胞和金黄色葡萄球菌)的体外抗菌效果和最小抑菌浓度(MIC)。结果表明,奥比沙星对这几种水生生物病原菌表现为中度和高度敏感,MIC最低可低于0.125μg/mL。奥比沙星对上述病原菌抑菌效果好,通过进一步的临床疗效研究,可望作为治疗水生生物细菌性疾病的抗菌新药。     

Phase I evaluation of CCNU (lomustine) in tumor-bearing cats

1-(2-Chloroethyl)3-cyclohexyl-1-nitrosourea (CCNU) is an alkylating agent in the nitrosourea subclass. A prospective evaluation of CCNU was done to determine the maximally tolerated dosage of CCNU in tumor-bearing cats. Response data were obtained when available. Twenty-five cats were treated with CCNU at a dosage of 50-60 mg/m3 body surface area. Complete hematologic data were available for 13 cats. Neutropenia was the acute dose-limiting toxicity. The median neutrophil count at the nadir was 1,000 cells/microL (mean, 2,433 cells/microL; range, 0-9,694 cells/microL). The time of neutrophil nadir was variable, occurring 7-28 days after treatment, and counts sometimes did not return to normal for up to 14 days after the nadir. Based on these findings, a 6-week dosing interval and weekly hematologic monitoring after the 1st treatment with CCNU are recommended. The nadir of the platelet count may occur 14-21 days after treatment. The median platelet count at the nadir was 43,500 cells/microL. No gastrointestinal, renal, or hepatic toxicities were observed after a single CCNU treatment, and additional studies to evaluate the potential for cumulative toxicity should be performed. Five cats with lymphoma and 1 cat with mast cell tumor had measurable responses to CCNU. Phase II studies to evaluate antitumor activity should be completed with a dosing regimen of 50-60 mg/m3 every 6 weeks.     

Furosemide continuous rate infusion in the horse: evaluation of enhanced efficacy and reduced side effects

Continuous rate infusion (CRI) of furosemide in humans is considered superior to intermittent administration (IA). This study examined whether furosemide CRI, compared with IA, would increase diuretic efficacy with decreased fluid and electrolyte fluctuations and activation of the renin-angiotensin-aldosterone system (RAAS) in the horse. Five mares were used in a crossover-design study. During a 24-hour period, each horse received a total of 3 mg/kg furosemide by either CRI (0.12 mg/kg/h preceded by a loading dose of 0.12 mg/kg IV) or IA (1 mg/kg IV q8h). There was not a statistically significant difference in urine volume over 24 hours between methods; however, urine volume was significantly greater after CRI compared with IA during the first 8 hours ([median 25th percentile, 75th percentile]: 9.6 L [8.9, 14.4] for CRI versus 5.9 L [5.3, 6.0] for IA). CRI produced a more uniform urine flow, decreased fluctuations in plasma volume, and suppressed renal concentrating ability throughout the infusion period. Potassium, Ca, and Cl excretion was greater during CRI than IA (1,133 mmol [1.110, 1,229] versus 764 mmol [709, 904], 102.7 mmol [96.0, 117.2] versus 73.3 mmol [65.0, 73.5], and 1,776 mmol [1,657, 2.378] versus 1,596 mmol [1,457, 1,767], respectively). Elimination half-lives of furosemide were 1.35 and 0.47 hours for CRI and IA, respectively. The area under the excretion rate curve was 1,285.7 and 184.2 mL x mg/mL for CRI and IA, respectively. Furosemide CRI (0.12 mg/kg/h) for 8 hours, preceded by a loading dose (0.12 mg/kg), is recommended when profound diuresis is needed acutely in horses.     

Prevalence of gastric lesions in racing Alaskan sled dogs

Human and equine athletes are reported to have a high prevalence of gastric disease, and anecdotal evidence suggests a similar phenomenon applies to racing sled dogs. To investigate the prevalence of gastric disease in racing sled dogs, we conducted 2 gastroscopy studies on dogs competing in the annual Iditarod Sled Dog Race. A pilot study of dogs that were either dropped from the 2000 Iditarod Sled Dog Race because of illness or that finished the race indicated that, approximately 5 days after competing, 10 of 28 dogs (35%) had endoscopic evidence of gastric ulceration, erosion, or hemorrhage. The next year, an endoscopic study of 73 dogs participating in the 2001 Iditarod race was performed in order to evaluate a larger population of dogs. Data from 70 of these dogs could be used; 34 (48.5%) had ulceration, erosion, gastric hemorrhage, or some combination of these findings. When this group of 70 dogs was compared retrospectively to a control group of 87 dogs presented to the Texas A&M University (TAMU) Veterinary Medical Teaching Hospital, the Iditarod sled dogs had a significantly higher prevalence (P = .049) of gastric lesions. These findings suggest that, similar to athletes of other species, elite canine athletes have an increased prevalence of gastric disease compared to the canine population at large.     

The Epidemiology of Gastrointestinal Nematodes of Dairy Cattle in Central Kenya

The epidemiology of H. placei and of other gastrointestinal nematodes in yearling dairy cattle was examined on two farms in Kiambu District, central Kenya during each of 13 one-month periods from April 1993 to April 1994. On each farm, 32 newly weaned dairy calves were given a single dose of albendazole and then placed on experimental pastures. Twelve of the animals were designated for bi-monthly slaughter (n = 2) and analysis of worm population characteristics and 20 were designated for blood and faecal collection and for weighing. Two parasite-free tracer calves were grazed alongside the weaner calves each month throughout the study period and were also slaughtered for analysis of worm populations. Faecal egg counts, haematological and serum pepsinogen determinations, herbage larval counts, and animal live weight changes were recorded monthly. The study revealed that Haemonchus placei, Trichostrongylus axei, Cooperia spp. and Oesophagostomum radiatum were responsible for parasitic gastroenteritis and that H. placei was the predominant nematode present in the young cattle on both farms. Faecal egg counts from resident cattle and necropsy worm counts revealed that pasture larval levels were directly related to the amount of rainfall. The total worm burdens in the animals were highest during the rainy season (March–June and October–December) and lowest during the dry seasons (July–September and January–February). The very low recovery of immature larvae of H. placei from the tracer calves indicated that arrested development is not a feature of the life cycle of this parasite in central Kenya. The maintenance of the parasite population depended on continuous cycling of infection between the host and the pasture. The agroclimatic conditions of the study area were such that, in general, favourable weather conditions for the development and survival of the free-living stages of gastrointestinal nematodes existed all year round.     

Diversity of Ectoparasites in Sheep Flocks in Sa~o Paulo,Brazil

The occurrence of ectoparasites in sheep flocks is frequently reported but seldom quantified. Sheep production used to be a predominantly family activity in the state of Sa~o Paulo (Brazil), but it began to become a commercial activity in the past decade. Thus, information about the ectoparasites existing in sheep flocks has become necessary. The present data were obtained by means of questionnaires sent to all sheep breeders belonging to the `Associaça~o Paulista de Criadores de Ovinos' (ASPACO; Sa~o Paulo State Association of Sheep Breeders). Response reliability was tested by means of random visits paid to 10.6% of the respondents. Most of the properties (89.5%) reported the presence of one or more ectoparasites. Screw-worm (Cochliomyia hominivorax) was the most frequent ectoparasite (72.5%), followed by bot fly larvae (Dermatobia hominis, 45.0%), ticks (Amblyomma cajennense) and Boophilus microplus, 31.3%) and finally lice (Damalinia ovis, 13.8%). Combined infestations also occurred, the most common one being screw-worm with bot fly larvae (36.0%) followed by bot fly larvae with ticks (13.9%), screw-worm with ticks (9.3%), bot fly larvae with lice (6.9%), and ticks with lice (5.0%). The most common triple combination was screw-worm, bot fly larvae and ticks (12.8%). Breeds raised for meat or wool were attacked by bot fly larvae and ticks more often than other breeds. Lice were only absent from animals of indigenous breeds. The relationships among these ectoparasites are discussed in terms of sheep breeds, flock size, seasonality and the ectoparasitic combinations on the host.     

Evaluation of biohydrogenation rate of canola vs. soya bean seeds as unsaturated fatty acids sources for ruminants in situ

An experiment was conducted to study disappearance of C14 to C18 fatty acids, lag times and biohydrogenation (BH) rates of C18 fatty acids of ground soya bean and canola seeds in situ. Three ruminally fistulated Dallagh sheep were used to determine ruminal BH of unsaturated fatty acids (UFAs). Differences in the disappearance of fatty acids through the bags and lag times were observed between the oilseeds. We saw that the longer the incubation time of the oilseeds in the rumen, the lower the content of C18:2 and C18:3. Significantly higher lag times for both C18:2 and C18:3 were observed in ground canola compared to ground soya bean. BH rates of C18:2 and C18:3 fatty acids in soya bean were three times higher than those of canola. These results suggest that the fatty acid profile of fat source can affect the BH of UFAs by rumen micro‐organisms. So that UFAs of canola had higher ability to escape from ruminal BH. It seems that fatty acid profile of ruminant products is more affected by canola seed compared to soya bean seed.     

Serum biochemical values and mineral element contents of tissues in yaks

Serum biochemical values and the wet weight to dry weight ratios of tissues were determined in yaks in Shandan county of Gansu province. The liver, kidney, heart and muscle contents of seven elements in yaks were also analysed. Most serum biochemical values were similar to those of cattle, camels and sheep, but the calcium concentration was considerably above the normal range for other ruminants. The liver contained the highest concentrations of copper, manganese and cobalt and the kidney of selenium, iron and calcium.Abbreviations Alb albumin - ALT alanine aminotransferase - AST aspartate aminotransferase - BUN blood urea nitrogen - Chol cholesterol - Glob globulin - -GT -glutamyl transpeptidase - IP inorganic phosphorus - TP total protein     

Avian brood parasitism — a growing research area in behavioral ecology (part Ⅱ)

正We are pleased to publish the second special issue on avian brood parasitism and to be responsible guest editors for the two special issues of Chinese Birds (Vol. 3, No. 4, 2012 and Vol. 4, No. 1, 2013), entitled "Avian Brood Parasitism - A Growing Research Area in Behavioral Ecology". The first issue was published in December 2012. The goal of the two special issues is to publish accumulated knowledge and some of the recent developments in     

Internal Parasites and Haematological Values in Cattle Slaughtered in Buea Subdivision of Cameroon

Tropical Animal Health and Production -