In vitro comparison of three materials as apical sealants of equine premolar and molar teeth

REASONS FOR PERFORMING STUDY: Surgical endodontic therapy is a conservative dental technique used in horses with some degree of clinical success. Failure of this procedure can partially be explained by inadequate sealing of the root apices with resultant microleakage in the periapical area. OBJECTIVES: To assess and compare in vitro sealing ability of 3 different dental restorative materials used as apical sealants during equine surgical endodontics. METHODS: Thirty extracted equine cheek teeth were divided randomly into 3 groups and subjected to apicoectomy and apical sealing using 3 materials: reinforced zinc oxide-eugenol cement; intermediate restorative material (IRM); a resin-modified glass ionomer; and amalgam. After apical sealing, the teeth were submerged in a solution of Procion Brilliant Cresyl Blue stain for a period of 7 days. The teeth were then washed, embedded in resin, sectioned and assessed microscopically for dye leakage around the apical restorations. RESULTS: Although the materials proved effective as apical sealants, some dye leakage was encountered in all 3 groups with no statistical difference (P = 0.114). CONCLUSIONS AND POTENTIAL RELEVANCE: IRM, a resin-modified glass ionomer and amalgam all showed comparative features as apical sealants when used in vitro in equine teeth. IRM is currently regarded as the superior material in clinical situations due to its ease of handling and lesser sensitivity to environmental moisture during placement compared to the other 2 materials.     

Inactivation of Clostridium haemolyticum toxic fluids and their antigenicity.

One hundred fifty-one isolates of Clostridium haemolyticum were examined for consistent toxin production following repeated serial transfers in laboratory media. Most of these isolates produced only small amounts of toxic materials and serial transfers appeared to reduce toxigenic characteristics. Eleven of the isolates consistenly produced measurable amounts of toxic materials. One of these isolates was used for production of toxic fluids that were concentrated by lyophilization and reconstitution to a smaller volume or by precipitation with ammonium sulphate followed by dialysis against water and glycerol. Known amounts of these substances were inactivated with formalin, heat, beta-propiolactone, ultra-violet irradiation and glutathione. The resulting toxoids were inoculated into guinea pigs and most were judged to be nonimmunogenic because the animals were unable to resist dermal challenge. Toxic materials with added glycine were inactivated with formaldehyde as readily as those without the amino acid but the resulting toxoids were immunogenic while those prepared without the amino acid were not.     

Trehalose in glycerol-free freezing extender enhances post-thaw survival of boar spermatozoa

Cryopreservation of boar semen is still considered suboptimal due to lower fertility as compared with fresh samples when glycerol, a permeating cryoprotectant, is used. Trehalose is a non-permeable cryoprotectant and nonreducing disaccharide known to stabilize proteins and biologic membranes. The aim of this study was to evaluate the cryosurvival and in vitro penetrability of boar spermatozoa when glycerol was replaced with trehalose in a freezing extender. Ejaculated Berkshire semen samples were diluted in egg yolk-based freezing extender containing glycerol (100 mM) or trehalose (0, 50, 100, 150, 200 and 250 mM) and cryopreserved using a straw freezing procedure. Thawed samples were analyzed for motility, viability, mitochondrial membrane potential (MMP), and acrosome integrity. In experiment 2, penetrability of spermatozoa cryopreserved with 100 mM glycerol or trehalose was examined. Replacement of cryoprotectant glycerol (100 mM) with trehalose had no effect on sperm viability, but replacing it with 100 mM trehalose improved motility, MMP and acrosome integrity significantly. Sperm motility and MMP were considerably higher in 100 mM trehalose, whereas the acrosome integrity was substantially higher in 100–250 mM trehalose. The in vitro penetration rate was also significantly higher in spermatozoa cryopreserved with trehalose (61.3%) than in those cryopreserved with glycerol (43.6%). In conclusion, 100 mM non-permeable trehalose can be used to replace glycerol, a permeating cryoprotectant, for maintenance of better post-thaw quality of boar spermatozoa.     

谷氨酰胺替代部分甘油对冻融猪精子获能和体外受精能力的影响

本试验旨在探索用谷氨酰胺（Gln）替代部分甘油对冻融猪精子体外获能和受精能力的影响，试验分为6组：3%甘油对照组和5个处理组（Ⅰ~Ⅴ组：2%甘油＋谷氨酰胺（0、20、40、80和100 mmol/L））。对冻融松辽黑猪精子的精子活力、质膜完整性、顶体完整性、线粒体膜电位、鱼精蛋白水平、获能及体外受精等指标进行了检测。结果显示，用谷氨酰胺替代部分甘油均对冻融精子质量有一定的改善作用，改善的程度受谷氨酰胺浓度的影响。与对照组相比，Ⅰ组精子的质量参数均显著下降（P<0.05）；与Ⅰ组相比，Ⅱ组精子活力、顶体完整性和活率显著提高（P<0.05），Ⅲ组精子线粒体膜电位显著提高（P<0.05），Ⅴ组精子活力、质膜完整性、顶体完整性、活率和线粒体膜电位均显著提高（P<0.05）。说明用谷氨酰胺替代部分甘油对精子质量具有很大的影响，且当谷氨酰胺为100 mmol/L时可得到更高质量的精子，因此，后续试验使用浓度为100 mmol/L的谷氨酰胺进行研究。与对照组相比，2%甘油＋100 mmol/L谷氨酰胺处理组精子鱼精蛋白缺失率显著下降（P<0.05），精子获能无显著差异（P>0.05），但胚胎卵裂率显著提高（P<0.05）。综上所述，谷氨酰胺可作为一种新型冷冻保护剂替代部分甘油来提高猪精液的质量，并降低甘油对猪精液的毒性作用，为猪精液的冷冻保存及商业化生产提供技术支撑。     

Cryopreservation of Hen Red Blood Cells

The cryoprotection of hen erythrocytes, used as reagent in virus titration, was investigated. The cryoprotective agents tested were neutralized polyvinylpyrrolidone (PVP), dimethylsulfoxide (DMSO) and glycerol. Good results were obtained with PVP, especially with PVP K15 (average molecular weight 10 000), and with DMSO, especially when used in a final concentration of 10 %, whereas glycerol was unfit for use in the concentrations tested. The red cell concentration, the suspending buffer before freezing and the washing procedure after thawing were of importance. The cells could be frozen and stored for at least three months without any significant effect on the virus titer.     

Effects of in ovo feeding with glycerol for broilers

The objective was to evaluate the effect of in ovo feeding with glycerol on post‐hatch development in broiler chicks. A total of 408 fertile eggs were divided into six experimental groups consisting of five 0.9% saline solutions containing various concentrations of glycerol (12.5, 25.0, 37.5 and 50.0 nmol/ml), and a placebo group (inoculation with saline only) and a control group (without inoculation). Inoculations were performed at 17 days of incubation for the evaluation of hatchability, embryo mortality, body and viscera weights, intestinal epithelium morphometry, blood glucose and liver glycerol kinase activity of chicks at hatching. Inoculation of solutions containing glycerol did not influence body weight at hatching and relative weights of liver, pancreas, intestine and breast. There was a quadratic effect of glycerol levels on the weights of yolk residue and gizzard and on blood glucose, and an increasing linear effect on spleen and heart weights. Higher duodenum and ileum villous height and deeper jejunum and ileum crypts were obtained with 50.0 nmol/ml of glycerol. A linear increasing effect was also observed in liver glycerol kinase activity; however, lower blood glucose was observed with 37.5 and 50 nmol/ml of glycerol. It is therefore concluded that glycerol may be used at doses of 25 nmol/ml as a substrate in in ovo feeding of broiler chickens. However, further studies must be conducted not only to establish an optimal dose but also to evaluate the combination of this substrate with other nutrients used in the in ovo feeding.     

The fate of glycerol entering the rumen of dairy cows and sheep

This study investigated the fate of glycerol entering the rumen, in particular whether glycerol could be absorbed across the rumen epithelium. Three non‐lactating rumen‐fistulated cows were used to calculate the overall disappearance rate of glycerol in vivo and evaluate the rate of ruminal glycerol absorption. Rumen epithelial tissues isolated from sheep were used to characterise glycerol transport properties. The rate of rumen microbial degradation of glycerol was then studied in an in vitro system under anaerobic and thermo‐regulated conditions. The results showed that glycerol can be absorbed from the rumen in significant amounts. The fractional rate of absorption of glycerol was not affected by variations in glycerol concentration in the buffer solution in the in vivo study. The glycerol absorption apparently occurred largely by passive diffusion and was probably not facilitated by carriers. Glycerol also disappeared via microbial digestion and outflow from the rumen through the omasal orifice.     

二甲基乙酰氨在鸡精液冷冻中的作用分析

用二甲基乙酰氨（ＤＭＡ）及甘油作为冷冻保护剂，对鸡精液进行冷冻保存，解冻后观察精子活力，并进行输精试验，发现以ＤＭＡ作为冷冻保护剂冷冻的精子解冻后活力及人工输精后的受精率都显著高于以甘油作冷冻保护剂的结果。经过毒性试验、冷冻试验及输精试验，发现ＤＭＡ的确是一种效果较好的冷冻保护剂。它在许多方面比甘油更为理想。本文还叙述了ＤＭＡ的性质及作用机理     

Characteristics of frozen-thawed spermatozoa cryopreserved with different concentrations of glycerol in captive Japanese black bears (Ursus thibetanus japonicus)

Seven mature Japanese black bears were used as semen donors, and a total of 7 semen samples collected from the animals by the electroejaculation method were cryopreserved in liquid nitrogen. Egg yolk-TRIS-citrate-glucose extender was used, and the effects of different final concentrations of glycerol, at 4-12% (v/v), on frozen-thawed spermatozoa were examined. No significant difference was observed in percent motility or percent abnormal morphology of frozen-thawed spermatozoa among the different glycerol concentrations. Percent viability and percent intact acrosomes of spermatozoa cryopreserved with 4 and 6% glycerol were significantly higher than those with 10 and 12% glycerol. These results suggest that a suitable glycerol concentration for freezing Japanese black bear semen within the range tested would be 4-6%.     

Comparison of Cryoprotective Effects of Lycopene and Cysteamine in Different Cryoprotectants on Bull Semen and Fertility Results

The objectives of this study were to compare glycerol and ethylene glycol at different concentrations as cryoprotectants and lycopene or cysteamine (with/without) as antioxidants in Tris extender for bull semen. Twenty‐four ejaculates were obtained from three bulls. Each ejaculate was split into four equal aliquots and diluted using both of the Tris extenders with glycerol (5% or 7%) or ethylene glycol (3% or 5%). After that, each extenders were split into three equal aliquots and added using both of the cysteamine 5 mm or lycopene 500 μg/ml, and control (without additives). The addition of 7% glycerol with cysteamine, 5% ethylene glycol with cysteamine and 3% ethylene glycol with cysteamine groups gave the lowest CASA motility than the other groups. However, 7% glycerol and 7% glycerol with lycopene resulted in a better rate of CASA progressive motility compared with that of other groups. Generally, all the lycopene groups signed better protective effects on acrosome and total morphology than the other groups. Glycerol 7% and 3% ethylene glycol with lycopene groups yielded to slight higher percentages of membrane integrity assessed by HOST than that of the other groups, but 7% glycerol with cysteamine and 3% ethylene glycol with cysteamine showed the worst percentages of membrane integrity. Glycerol 7% and 5% glycerol with lycopene gave rise to a higher value of VAP, VSL and VCL compared with that of the other groups. On the contrary, adding to 5% glycerol with cysteamine showed negative effect for VAP, VSL, VCL and ALH values. All cryoprotectant groups with lycopene decreased chromatin damage than the other groups. Ethylene glycol 3% led to lower non‐return rates of inseminated cows. However, this result was not considered to be statistically important.     

Evaluation of a Hemostasis Model for Teaching Basic Surgical Skills

The need for alternative methods of teaching veterinary medicine and surgery has increased in recent years because of increasing costs and changing public opinion. For these reasons a hemostasis model was developed that mimics the arteries and veins of the peripheral vascular system, and can be used to teach the basic skills involved in blood vessel ligation and division. This study evaluated the effectiveness of the fluid hemostasis model compared with using live animals for teaching these skills. Forty sophomore veterinary students participated in the study. Two groups of 20 students each received identical instruction in the basic techniques required for vessel ligation and division. The students then completed various exercises using inanimate models to objectively evaluate their psychomotor skills. Both groups then practiced the techniques for equal time periods; one group used the hemostasis model and the other performed a splenectomy on live dogs. After the practice session, the students were videotaped (for later evaluation), as they performed vessel ligations and divisions. The students then repeated the exercises using the inanimate models for evaluation of skills improvement. Questionnaire responses before and after the project were obtained to determine the students' views on the need for inanimate models for teaching purposes. Results of this study indicate that the hemostasis model was as effective as live animals for teaching the basic skills involved in blood vessel ligation. The students' opinions regarding the use of properly designed inanimate models for teaching these skills were dramatically changed.     

兽医流行病学教学方法改革的探索与实践

兽医流行病学是研究动物群体中疾病频率分布及其决定因素的学科。为提高教学质量,积极配合以学生为主体的教学模式转变,在兽医流行病学教学中采用了PBL、TBL、案例教学等新型教学方法,极大地激发了学生学习热情,培养了学生创新与团队意识,取得良好教学效果。     

Artificial insemination with canine spermatozoa frozen in a skim milk/glucose-based extender

Due to the recent outbreak of avian influenza, transportation of frozen canine semen with egg yolk has been sharply restricted. Thus, there is urgent need to develop a novel egg yolk-free extender for freezing canine spermatozoa. In the present study, the effect of using skim milk/glucose (SG)-based extender without egg yolk on the motility and fertilizing capacity of canine spermatozoa frozen-thawed in the presence of glycerol was examined. There was a tendency for the proportion of motile spermatozoa exposed to SG-based extender for 3 h to be higher than that exposed for 1 h, but the difference was not significant. The motility and other viability parameters of canine spermatozoa after thawing were similar to those obtained with an egg yolk-based extender. When spermatozoa frozen with SG-based extender containing glycerol after 3 h exposure were transcervically inseminated into 2 recipient bitches, a total of 6 pups were obtained. These results suggest that a simple extender composed of skim milk, glucose and glycerol is useful for cryopreservation of canine spermatozoa, which may contribute to improved exchange of genetic material and efficient production of companion and working dogs, such as guide dogs for the blind.     

Effects of various cryoprotectants on the survival of mouse embryos cryopreserved by the quick freezing method

The effects of concentrations of glycerol, ethylene glycol or dimethylsulphoxide (DMSO) in the presence of either 0.25 M lactose or sucrose on the post-thaw survival of mouse quickly-frozen compacted morulae were studied. In this method, the embryos were directly frozen in liquid nitrogen (LN2) vapor at approximately -170 degrees C for 2 min before being plunged into LN2. High survival rates of frozen-thawed embryos were obtained when the freezing medium contained 3 M ethylene glycol with either 0.25 M lactose or sucrose (76.5 and 70.2%, respectively). When the embryos were frozen in glycerol, significantly high survival was obtained with 3 M glycerol + 0.25 M sucrose (73.5%, P less than 0.001). However, a freezing medium containing DMSO with either sugar gave lower survival rates. At a higher concentration of 4 M, ethylene glycol with 0.25 M lactose gave significantly higher survival rate than glycerol or DMSO (P less than 0.05). Significantly higher rates were obtained at 2 M with all 3 cryoprotectants when the freezing medium contained lactose rather than sucrose (P less than 0.05). This study showed that glycerol and ethylene glycol were effective cryoprotectants in the quick freezing of mouse embryos, while DMSO was less effective. In addition, the protective effects of these cryoprotectants are affected by their concentrations and the type of sugar used.     

The Effect of Glycerol on the Viability, Mitochondrial Function and Acrosomal Integrity of Bovine Spermatozoa

Contents Eight bull ejaculates were split to evaluate the effects of glycerol on sperm organelle function. Although glycerol protects sperm membranes during cryopreservation, preliminary data suggested that glycerol was detrimental to sperm organelles to varying degrees. To assess the compartmental effects, three organelle-specific fluorophores were used to analyze with (G+) and without glycerol (G–) in spermatozoa stored for 24 h at 5°C in an egg-yolk-based extender. The mitochondrial probe, 5,5′,6,6′-tetrachloro-1,1′,3,3′-tetraethyl benzimidazolylcarbocyanine iodide (JC-1) was used to examine the level of mitochondrial metabolic function by it’s discrimination between high (J-aggregate staining, red-orange) and low membrane potentials (JC-1 monomeric staining, green); while acosomal reacted spermatozoa were identified using fluorescein-labelled lectin from arachis hypogaea, PNA-FITC. The proportions of living and dead spermatozoa were determined by staining with the combination of SYBR-14 and propidium iodide (PI). Split-plot analysis of variance revealed that within bulls, glycerol altered the proportions of sperm staining with each organelle-specific fluorophore to varying degrees. The proportion of spermatozoa labelled with SYBR-14, indicating intact plasmalemmae, were not affected by the addition of glycerol (p = 0.11). Although the total proportion of JC-1-labeled spermatozoa were similar in G– and G+ samples (p = 0.90), the presence of glycerol decreased the proportion of spermatozoa that exhibited J-aggregate staining (p < 0.01) while producing an increase in monomeric staining (p = 0.02). The proportions of acrosome-reacted spermatozoa, however, were greater in the G– samples than in the G+ samples as indicated by PNA-FITC (p = 0.03). These findings suggest that mitochondria, acrosomes and the plasmalemmae of unfrozen spermatozoa vary in their response to the addition of the cryoprotectant glycerol.     

Digestible and metabolizable energy of crude glycerol for growing pigs

The apparent DE and ME values of crude glycerol for growing pigs were determined in 5 experiments using crude glycerol (86.95% glycerol) from a biodiesel production facility, which used soybean oil as the initial feedstock. Dietary treatments were 0, 5, or 10% glycerol addition to basal diets in Exp. 1; 0, 5, 10, or 20% glycerol addition to basal diets in Exp. 2; and 0 and 10% crude glycerol addition to the basal diets in Exp. 3, 4, and 5. Each diet was fed twice daily to pigs in individual metabolism crates. After a 10-d adjustment period, a 5-d balance trial was conducted. During the collection period, feces and urine were collected separately after each meal and stored at 0 degrees C until analyses. The GE of each dietary treatment and samples of urine and feces from each pig were determined by isoperibol bomb calorimetry. Digestible energy of the diet was calculated by subtracting fecal energy from the GE in the feed, whereas ME was calculated by subtracting the urinary energy from DE. The DE and ME values of crude glycerol were estimated as the slope of the linear relationship between either DE or ME intake from the experimental diet and feed intake. Among all experiments, the crude glycerol (86.95% glycerol) examined in this study was shown to have a DE of 3,344 +/- 8 kcal/kg and an ME of 3,207 +/- 10 kcal/kg, thereby providing a highly available energy source for growing pigs.     

抹茶椰子乳饮料制作工艺的研究

选用生牛乳、椰子粉、抹茶粉为主要原料,开发一款抹茶椰子乳饮料,以感官评分为指标,通过正交试验方法优化了抹茶椰子乳饮料配方及稳定剂的复配方案。最优配方为:生牛乳添加量4.5%、椰子粉添加量2.5%、抹茶粉添加量0.3%、白砂糖添加量6.0%,稳定剂的最优配比结果为:单、双甘油脂肪酸酯添加量0.1%、三聚磷酸钠添加量0.05%、结冷胶添加量0.03%。在该配方及稳定剂组合条件下,可获得香甜适口、风味醇厚、货架期稳定的抹茶椰子乳饮料。     

Extenders containing dimethylformamide associated or not with glycerol are ineffective for ovine sperm cryopreservation

The study aimed at testing the effectiveness of dimethylformamide, alone or combined with glycerol, as cryoprotectant for freezing ram semen. Ejaculates from nine rams were cryopreserved in Tris-based extenders, containing 5% of glycerol, association of dimethylformamide with glycerol, in four proportions achieving 5% of cryoprotectors in the media and pure dimethylformamide (2, 3, 4 and 5%) in replacement to glycerol. The samples were diluted to 100 × 10(6) sptz/ml and stored in 0.25-ml straws in liquid nitrogen. After thawing (37 °C for 30 s), motility was preserved better by the extender containing 5% of glycerol (p < 0.05). The extenders containing pure dimethylformamide, or more than 2% in combination with glycerol, provided sperm motilities close to zero. Plasma and acrosomal membrane integrity were preserved better (p < 0.05) in the extender containing 5% glycerol. It can be concluded that dimethylformamide, alone or combined with glycerol, has no beneficial effects on ovine semen cryopreservation.     

16份无芒雀麦种质资源生产性能与营养品质的综合评价

为了筛选出生产性能与营养品质表现优良的无芒雀麦(Bromus inermis)种质材料,测量和分析了国内外16份无芒雀麦种质资源生产性能和营养品质的相关指标,并运用聚类分析、灰色关联度分析进行综合评价。结果表明：不同无芒雀麦种质材料之间生产性能与营养品质差异显著(P < 0.05),其中Q6、Q8、Q2的鲜草产量与Q16、Q4的干草产量显著高于其他种质材料(P < 0.05),可作为追求产草量的基础材料利用;Q16粗蛋白含量高,中性洗涤纤维含量低,牧草消化率高,营养品质好;Q2、Q4、Q10、Q14叶茎比显著高于其他种质材料(P < 0.05)。聚类分析将16份种质材料聚为4类,聚类结果与原产地关系较小。根据灰色关联度分析,叶茎比、干草产量、粗灰分、粗蛋白在无芒雀麦生产性能与营养品质综合评价系统中权重最大,可作为无芒雀麦品种评价和筛选时的关键性状;Q6、Q4、Q10、Q16、Q2、Q8与理想品系关联系数最大,综合表现最好,可为无芒雀麦品种改良和新品种培育提供基础材料。