酶法辅助超声提取红菜苔皮花色苷及其降血糖活性研究

研究旨在优化花色苷的提取工艺并考察其降血糖活性。试验以红菜苔皮为原料,通过单因素试验与正交试验探究酶法辅助超声优化花色苷的提取工艺。结果显示,酶法辅助超声提取红菜苔皮花色苷的最佳工艺条件为超声时间40 min、液料比20 mL/g、果胶酶与纤维素酶比例3∶1、pH值2.2、加酶量2‰,此条件下提取红菜苔皮花色苷含量为7.61 mg/g。体外降血糖试验发现,红菜苔皮花色苷对α-淀粉酶和α-葡萄糖苷酶的半数抑制浓度(IC₅₀值)分别为3.32、6.46 g/L,当花色苷水平为7.00%时,花色苷对α-淀粉酶的抑制率为77.00%,当花色苷水平为8.00%时,花色苷对α-葡萄糖苷酶的抑制率为86.00%,花色苷对α-淀粉酶和α-葡萄糖苷酶为抑制类型均为反竞争的抑制。研究表明,酶法辅助超声提取红菜苔皮花色苷是一种高效的提取方法,可为天然红色素的生产及食用色素品种的筛选提供参考。     

山茱萸活性成分的鉴定及降糖效果的研究

目前，临床常用的降血糖药物如胰岛素和各种化学合成药物都具有多重不良反应，易造成患者的急性低血糖，乳酸中毒和肝、肾损伤。迄今为止没有一种药物能彻底治愈糖尿病，科学家将希望寄予无毒副作用的天然植物的药用开发上。山茱萸作为我国传统药物常出现在中医降血糖的组方中，但其明确的降血糖效果和降血糖活性成分目前还不清楚。试验采用多种方法提取山茱萸中的熊果酸，通过动物试验评价其降血糖效果，这将为该药物的进一步开发提供重要的科学依据。     

热水浸提和微波萃取桑叶多糖的药效比较及降血糖机制初探

通过动物试验,对采用热水浸提法和微波萃取法所得桑叶多糖的降血糖效果进行比较,并探讨其降血糖机制。结果表明,微波萃取桑叶多糖的降血糖效果好于热水浸提的桑叶多糖;桑叶多糖可以提高四氧嘧啶诱导糖尿病模型小鼠机体的超氧化物歧化酶(SOD)活性,极显著抑制糖尿病模型小鼠的脂质过氧化作用,修复糖尿病模型小鼠的胰岛细胞损伤,因此推测桑叶多糖对治疗四氧嘧啶诱导的糖尿病模型小鼠具有多项代谢调节作用。     

丝素降血糖效果的初步研究

以高血糖小白鼠为实验动物,测定了丝素粉、丝素溶液的降血糖效果。用等量丝素粉、丝素溶液及降血糖药剂盐酸二甲双胍片灌胃的高血糖小白鼠的餐后血糖值,在4周后分别下降了13.81%、16.33%、18.41%。与已经开发利用的化学降血糖药剂盐酸二甲双胍片相比,丝素降血糖的效果也比较明显。研究结果可为蚕丝资源的综合利用和开发人体降血糖保健食品提供试验数据。     

黑洋葱粗多糖的提取及降血糖作用研究

为了研究黑洋葱有效成分对高血糖模型小鼠降血糖的作用,试验采用整头洋葱为原料,发酵获得黑洋葱,以腹腔注射生理盐水为对照,通过四氧嘧啶诱发小鼠糖尿病的试验验证黑洋葱有效成分的降血糖作用,并与黑洋葱汁的降血糖作用进行对比。结果表明:黑洋葱粗多糖和黑洋葱汁均能有效对抗四氧嘧啶诱发小鼠的高血糖,其中黑洋葱粗多糖的效果较黑洋葱汁更明显。说明黑洋葱粗多糖对四氧嘧啶致高血糖模型小鼠有降血糖作用。     

桑宁茶多糖对糖尿病小鼠的降血糖作用研究

为探寻桑宁茶多糖对糖尿病模型小鼠的降血糖作用 ,利用分级纯化的方法 ,得到 3种不同纯度的桑宁茶多糖 (Ⅰ、Ⅱ、Ⅲ ) ;以常规降糖药格列本脲 (优降糖 )为阳性治疗对照 ,通过对糖尿病小鼠进行降血糖治疗试验 ,研究了 3种桑宁茶多糖的降血糖作用。结果表明 :3种桑宁茶多糖对链脲佐菌素诱导的糖尿病小鼠均有显著的降血糖作用 ,降糖效果以初步纯化的多糖效果最好 ,且效果均优于格列苯脲。     

全蚕粉降血糖作用研究进展

概述了近10年来国内关于全蚕粉成分的测定、全蚕粉降血糖的活性成分和作用机理,全蚕粉降血糖的动物试验与临床研究、全蚕粉制作的加工工艺等方面的研究,提出对全蚕粉进一步研究和开发的思路.     

家蚕、桑叶粗提物降血糖的作用效果

为进一步开发高效、多剂型的蚕、桑降血糖制剂,研究了不同品种的家蚕和桑叶粗提物降血糖的体外和体内实验效果。结果表明:家蚕提取物的降血糖效果明显优于桑叶粗提物;蚕品种间存在差异,桑品种间差异显著。灌胃家蚕和桑叶粗提物4周后的动物,其餐后血糖值分别降低了33.48%和24.24%。对不同蚕、桑品种降血糖差异的作用机理进行了探讨。     

全蚕粉(SP)降血糖的作用效果及其机理的研究

研究了全蚕粉及其对实验鼠降血糖的作用。初步检测发现全蚕粉中含有三碘甲腺原氨酸 (T3) ,不含甲状腺素T4。试验证明全蚕粉具有显著降血糖的效果。添加 0 1%的全蚕粉饲喂高血糖实验鼠 4周 ,摄食后 1h和 2h的血糖值分别降低了 13 81% (p <0 0 5 )和 11 0 7%。T淋巴细胞转化率提高 35 % (p <0 0 1)。实验还对全蚕粉降血糖的作用机理进行了探讨 ,认为全蚕粉的降血糖作用可能与抑制小肠粘膜α 麦芽糖苷酶活性有关     

马齿苋多糖对四氧嘧啶糖尿病小白鼠的降糖作用

马齿苋(Portulaca oleracea L.)是一种药食同源植物,是马齿苋科一年生草本植物马齿苋的干燥地上全草,别名为五行草、酸苋、猪母菜、地马菜、马蛇子菜、长寿菜等,具有抗糖尿病、抗细菌、抗病毒、抗衰老、提高免疫力等功能.马齿苋富含α-不饱和脂肪酸、β-胡萝卜素、黄酮、香豆素、单萜糖苷、生物碱、多糖等化学成分.马齿苋多糖(POP)具有增强机体免疫力、抗肿瘤、抗氧化等作用,而有关降血糖作用未见相关报道,为深入研究其发挥药理作用的有效成分及降血糖效果,本试验研究了马齿苋多糖对四氧嘧啶糖尿病小白鼠的降血糖作用,现介绍如下.     

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.     

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.     

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.     

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