Adonis microcarpa (pheasant''s eye) toxicity in pigs fed field pea screenings

Seed of Adonis microcarpa (pheasant's eye) fed at 5.6 g/kg of the diet induced virtually total feed refusal within 3 d in growing and finishing pigs. It also caused vomiting, rapid and shallow breathing and death in a minority. These effects were probably caused by cardiac glycosides whose structure and effects closely resemble those of digoxin. Feed intake and growth recovered within 2 weeks of removal of the seed.     

聚合体不影响Alimet(R)的生物利用率

前言 1979以来,随着蛋氨酸羟基类似物的诞生--一种粉状D,L-蛋氨酸(DLM)的替代产品,世界蛋氨酸添加剂市场开始发生巨大的转变.Alimet(R)就是蛋氨酸市场上替代DLM的知名品牌,它开创性地为饲料生产者提供了一种液态的蛋氨酸源.随着Alimet(R)的出现,粉状蛋氨酸源和液态蛋氨酸源生产商间就这两种产品的化学结构和生物效价也开始了激烈的争论,也正是由于这种争论强化了蛋氨酸羟基类似物在全球蛋氨酸添加剂市场上的地位,蛋氨酸添加剂市场从此向液态蛋氨酸羟基类似物稳步转变.     

The survival and fecundity of buffalo flies after treatment of cattle with three anthelmintics

Two anthelmintics with known insecticidal action (ivermectin and closantel) and one with no recorded effect on insects (levamisole) were tested to evaluate their effects on buffalo fly (Haematobia irritans exigua). Blood from animals given closantel or levamisole had no significant effect on mortality of buffalo flies in an in-vitro assay. In contrast, blood from animals given ivermectin showed a dose-dependent effect on the mortality of buffalo flies. At 24 h after one injection of the recommended dose of ivermectin, 98% of the flies applied to cattle in an in-vivo assay are killed. Blood from cattle injected with ivermectin killed 95% of flies 8 d after injection and still killed 15% of flies at 18 days after injection. Surviving flies laid almost no eggs and this effect on flies was significant up to 33 d after injection. The results indicate that ivermectin may be useful to control buffalo fly populations in the field.     

Dynamics of thymocyte-stromal cell interactions visualized by two-photon microscopy

Thymocytes are selected to mature according to their ability to interact with self major histocompatibility complex (MHC)-peptide complexes displayed on the thymic stroma. Using two-photon microscopy, we performed real-time analysis of the cellular contacts made by developing thymocytes undergoing positive selection in a three-dimensional thymic organ culture. A large fraction of thymocytes within these cultures were highly motile. MHC recognition was found to increase the duration of thymocyte-stromal cell interactions and occurred as both long-lived cellular associations displaying stable cell-cell contacts and as shorter, highly dynamic contacts. Our results identify the diversity and dynamics of thymocyte interactions during positive selection.     

YIGSR, a synthetic laminin pentapeptide, inhibits experimental metastasis formation

The invasion of tumor cells through basement membranes is a critical step in the formation of metastases. The binding of the malignant cells to laminin in the basement membranes allows their attachment and activates their invasiveness. Recently a synthetic nonapeptide from the B1 chain sequence of laminin was identified as a major site for cell binding. A pentapeptide within the nonapeptide sequence was found to reduce the formation of lung colonies in mice injected with melanoma cells and also to inhibit the invasiveness of the cells in vitro.     

Characterization of envelope and core structural gene products of HTLV-III with sera from AIDS patients

The envelope (env) and structural (gag) gene products of human T-cell leukemia (lymphotropic) virus type III were identified by immunoaffinity chromatography, immunoprecipitation, and two-dimensional oligopeptide mapping methods. The env gene specifies a glycosylated polypeptide with a molecular weight of 160,000 (gp160) that is processed to gp120 and smaller gene products. The gag gene specifies two polypeptides of 70,000 and 55,000 molecular weight (p70 and p55), both of which contain p24, the major structural protein of the mature virion. The techniques in this study can be used to define the extent of variability of the env gene product among different virus isolates and may identify the nature and patterns of the humoral immune response that lead to an immunologically protected state.     

Oestrous Synchronization,Ovarian Superovulation and Intraspecific Transfers From a Closed Breeding Colony of Inbred SLA Miniature Pigs

The inbred SLA miniature pig is a unique animal model developed for organ transplantation studies and pre‐clinical experimental purposes. Reported oestrous synchronization and superovulation treatments were examined in two SLA haplotypes (AA and DD) to allow collection of embryos for both practical embryo transfer and experimental technologies from a closed breeding colony. Pre‐puberal miniature pigs were poor responders to oestrous synchronization treatments, while post‐puberal sows were equivalent to commercial sows. Following superovulation, the ovulation number (corpora .hemorrhagica) was higher (p < 0.05) in the cycling sows when compared with non‐cycling sows. Ovulations were equivalent to commercial pre‐puberal gilts and non‐cycling sows (p > 0.05). No difference in ovulation number between haplotypes was observed, which differs from the previous report (DD>AA). Collection of zygotes for pronuclear injection was the highest in the non‐cycling post‐puberal miniature pig group (p < 0.05), although significantly lower when compared with the commercial pig treatment groups (p < 0.05). The incidence of cystic endometrial hyperplasia in our colony was equivalent to rates observed in commercial pigs. Pronuclear visualization following centrifugation was the highest in the non‐cycling miniature sow group and approximates to about 25% of ovulations and about half the rate observed in the commercial pigs (50%). Miniature pig embryos transferred between SLA haplotypes and transfer of DD embryos to commercial pigs resulted in live births at a higher efficiency than previously reported. This study demonstrates the feasibility of undertaking assisted reproductive technologies in a closed breeding colony of inbred SLA miniature pigs without compromise to the breeding programmes.