夏枯草提取物的抗氧化活性

对夏枯草（Prunella vulgaris）不同溶剂提取物体外抗氧化活性进行评价,为进一步开发利用夏枯草提供参考。采用70%乙醇超声波提取,然后用等体积的乙酸乙酯、正丁醇和水萃取,得到乙酸乙酯、正丁醇和水提取物,并以BHT为对照,研究不同溶剂提取物的抗氧化活性。结果表明,夏枯草提取物具有良好的抗氧化性。不同溶剂提取物及BHT清除DPPH·的能力高低次序为乙酸乙酯提取物＞正丁醇提取物＞BHT＞水提物,清除·OH的能力高低次序为BHT＞乙酸乙酯提取物＞正丁醇提取物＞水提物,清除O-2·的能力高低次序为乙酸乙酯提取物＞水提物＞BHT＞正丁醇提取物,还原力高低次序为BHT＞乙酸乙酯提取物＞正丁醇提取物＞水提物。夏枯草乙酸乙酯提取物具有较强的抗氧化活性。     

植物提取物对家禽肠道健康的调控及其作用机制

植物提取物中的活性物质有黄酮类、植物精油、生物碱、茶多酚、皂苷和多糖等,这些活性物质在动物机体内具有抗菌、抗氧化、增强肠道免疫、促进消化酶分泌及改善肠道健康等多种生理功能,且具有无残留和无耐药性等特点,是抗生素的理想替代品之一。本文借鉴国内外学者近年来的植物提取物在家禽肠道健康调控方面的研究成果,对植物提取物的抑菌活性成分及抗菌机制进行了概括和阐述,重点综述了植物提取物对家禽肠道消化生理、肠道发育及黏膜形态、肠道菌群、肠道免疫和肠道有害代谢产物的影响及其作用机制,以期为今后在家禽生产中合理使用植物提取物提供科学依据。     

夏枯草等14味中药对金黄色葡萄球菌的体外抑菌活性

采用索氏提取,超声波和水煎煮方法提取夏枯草等14味中药的有效部位,应用二倍试管稀释法分别测定其提取物对金黄色葡萄球菌的最小抑菌浓度（MIC）和最小杀菌浓度（MBC）。结果显示,夏枯草、虎杖、何首乌、连翘、柴胡、穿心莲、地榆7味中药有效部位对金黄色葡萄球菌的抗菌活性最强,其MIC为1．953～3lI250g／L,MBC为3．90～31．25g／L;佛手、黄柏2味中药有效部位具有较强的体外抗菌活性,其MIC值为62．5g／L,MBC值为125．0g／L;大青叶、板蓝根、金银花、杜仲、白头翁5味中药有效部位的抗菌活性较差,其MIC值为125．0g／L,MBC值为250．0,≥250．0g／L。不同中药有效部位对金黄色葡萄球菌的抗菌活性有所差异,其中夏枯草、虎杖、何首乌、地榆和佛手有效部位对金黄色葡萄球菌具有较好的抗菌活性。     

Antigenic analyses of tissues and excretory and secretory products from Strongylus vulgaris.

Rabbit antisera were prepared against veronal buffered saline extracts of L4 and L5 Strongylus vulgaris, adult S. vulgaris and adult Strongylus equinus retrieved from naturally infected horses. In agar gel diffusion with these antisera, adult S vulgaris and S. equinus each appeared to have at least one unique antigen; larval S. vulgaris appeared to have two species-specific and two stage-specific antigens. There were several common antigens. Excretory and secretory products were collected also from L4 and L5 an maintained over several days in tissue culture fluid. In agar gel diffusion against the above rabbit antisera, a stage-specific antigen was found also in excretory and secretory products. In addition, excretory and secretory products had three antigens in common with adult and larval S. vulgaris, but only one of these was common to adult S. equinus. The excretory and secretory products appear, therefore, to have two species-specific and one stage-specific antigens.     

谷氨酰胺对免疫细胞的影响研究进展

谷氨酰胺作为一种条件性必需氨基酸,在动物处于特殊生长阶段如幼龄期或在应激期间都显示出明显的免疫促进作用。动物免疫力的高低直接取决于各种免疫细胞如淋巴细胞、中性粒细胞、巨噬细胞的生长情况和免疫应答能力,谷氨酰胺的免疫促进作用与影响免疫细胞生长和免疫应答能力的发挥密切相关。本文就谷氨酰胺与免疫细胞增殖、分化、凋亡、分泌和热休克反应的研究进展做一综述。     

百里香在草地植被恢复中的优势及展望

百里香为唇形科百里香属常见种,在我国分布较为广泛,其野生资源丰富。研究表明,百里香不仅是重要的香料和园林植物,还是很好的草地植被恢复植物。综述了百里香的生物学特性及其在草地植被恢复中的优势,并对其开发利用前景进行了展望,以期为全方位挖掘百里香的应用价值提供参考。     

In vivo activation of equine eosinophils and neutrophils by experimental Strongylus vulgaris infections

Eosinophils and neutrophils from ponies with Strongylus vulgaris-induced eosinophilia (eosinophilic ponies; activated eosinophils and neutrophils) were assayed in vitro for chemotactic and chemokinetic responses to zymosan-activated serum (ZAS) using the filter system in Boyden chambers, for Fc and complement (C) receptors using the EA and EAC-rosette assays, respectively, and for phagocytic and bactericidal activities using opsonized Escherichia coli and the acridine orange method. The responses of activated eosinophils and neutrophils in the above assays were compared with those of eosinophils and neutrophils from S. vulgaris-naive ponies without eosinophilia (noneosinophilic ponies; nonactivated eosinophils and neutrophils). Differences in cell density following centrifugation in a continuous Percoll gradient were used to further characterize the heterogeneity of activated eosinophils and neutrophils. Activated and nonactivated eosinophils demonstrated similar chemotactic responses to ZAS while activated and nonactivated neutrophils demonstrated similar chemokinetic responses to ZAS. A higher percentage of activated eosinophils and neutrophils expressed Fc and C receptors compared with nonactivated cells (P less than 0.05). Generally, higher percentages of eosinophils and neutrophils expressed C than Fc receptors. However, the percentage of neutrophils with both receptors was higher than that of eosinophils. Phagocytosis and killing of E. coli by either type of eosinophil were not consistently observed. Both activated and nonactivated neutrophils phagocytized E. coli and significant differences between the two cell types were not observed. The bacterial activity, however, of activated neutrophils was significantly greater than that obtained using nonactivated neutrophils (P less than 0.05). Activated eosinophils and neutrophils were both separated into two distinct fractions based on differences in cell densities. A higher percentage of band 2 eosinophils (density of 1.106) expressed C receptors than did band 1 eosinophils (density of 1.049) (P less than 0.05). A higher percentage of band 1 neutrophils (density of 1.072) expressed both Fc and C receptors and these neutrophils were more phagocytic and bactericidal than were band 2 neutrophils (density of 1.082) (P less than 0.05). These data suggest that equine eosinophils and neutrophils are activated by chronic S. vulgaris infections.     

The use of Thymi Herba as feed additive (0.1%, 0.5%, 1.0%) in weanling piglets with assessment of the shedding of haemolysing E. coli and the detection of thymol in the blood plasma

Thymi Herba (Thymus vulgaris, rubbed) was given as feed additive to weanling piglets. 3 concentrations (0.1%, 0.5%, 1%) were tested against a control group. Rectal swabs were collected weekly and were sent in for bacterial testing. The shedding of haemolysing E. coli was evaluated. There was no significant difference in the shedding of haemolysing E. coli between the 4 groups. Neither was there a difference in the distribution of the various serotypes. Thymol was detected in the blood plasma in all thyme groups. The increase in thymol level with greater amounts of thyme herb was significant. Three days after withdrawal of the feed additive no thymol levels were detected. The study results did not reveal any effects on haemolysing E. coli in the gut.     

Effect of Cysticercus cellulosae on neutrophil function and death

Neutrophils, eosinophils and macrophages interact with invading parasites and naive hosts. The initial reaction of leukocytes is the generation of reactive oxygen species (ROS). The cytotoxic effects of extracts derived from intact Cysticercus cellulosae and from the scolex or membrane fractions on neutrophils were examined. DNA fragmentation of neutrophils was observed when cells were incubated with an extract from the intact metacestode; however, the addition of antioxidant enzymes to the incubation medium had a protective effect. The scolex and membrane extracts did not affect DNA fragmentation of neutrophils. Hydrogen peroxide production of neutrophils incubated with metacestode fractions from C. cellulosae increased by 190% (total extract), 120% (scolex) or 44% (membrane). An increase in antioxidant catalase activity (28%) concomitant with the increased production of ROS was observed in neutrophils incubated with metacestode fractions, which could be an attempt at self-protection. ROS production by neutrophils in the presence of the intact cysticerci extract did not alter phagocytosis. In contrast, the scolex and membrane fractions increased the phagocytic capacity of neutrophils by 44 and 28%, respectively. The results showed that the extract from intact C. cellulosae was toxic for neutrophils via ROS production, leading to DNA fragmentation and inhibition of phagocytic capacity, but neutrophils are able to protect themselves against oxidative stress by via catalase activity.     

Innate immune traits differ between Meishan and Large White pigs

A panel of innate immune traits were compared between Meishan and Large White pigs. These pigs were of similar age and kept under the same environmental conditions to reduce non-genetically derived variation in immune traits. The animals were all apparently healthy and were not experimentally challenged with any pathogen during the study. The measures only required a small blood sample. Total white cell counts were similar between the pig breeds. However, the numbers of lymphocytes, neutrophils and monocytes differed significantly, with Meishans having higher neutrophil and monocyte counts and lower lymphocyte counts. Flow cytometric methods were used to determine quantitatively the characteristics and function of neutrophils and monocytes. Meishan neutrophils were smaller and less complex than Large White neutrophils, and phagocytosis of Escherichia coli and the ensuing oxidative burst was lower in Meishan neutrophils compared to Large White neutrophils. Monocyte phagocytosis of E. coli was significantly less than that of neutrophils in both breeds but the function of Meishan monocytes as measured by phagocytosis and tumour necrosis factor alpha (TNFalpha) release did not differ from that of Large White monocytes. Levels of acute phase proteins also differed between the breeds with a significantly higher proportion of Meishans having elevated serum amyloid A levels. However, Meishans had lower alpha(1)-acid glycoprotein levels than Large Whites and haptoglobin levels were similar. Such differences in innate immune traits may have implications in the resistance to infection by a broad range of pathogens and subsequent disease effects in these breeds. Further studies are warranted to investigate the genes underlying these traits.     

Emigration of polymorphonuclear leucocytes into the intestinal lumen of the neonatal piglet in response to challenge with K88-positive Escherichia coli

The emigration of neutrophils from the blood of neonatal piglets into the intestinal lumen in response to a K88-positive strain of Escherichia coli was investigated. The pig herd used was of known genetic susceptibility to K88-positive E coli and had recently experienced an outbreak of neonatal diarrhoea. Neutrophil emigration depended on certain factors. Neutrophils emigrated into ligated loops in susceptible piglets sucking immune colostrum from susceptible dams but not into loops in colostrum deprived resistant piglets or piglets sucking non-immune colostrum from resistant dams. In susceptible, colostrum deprived piglets neutrophils in intestinal contents were only associated with severe lesions. Large numbers of neutrophils which appeared at several foci on the villi were observed in three of six resistant piglets that sucked immune colostrum from susceptible dams. It was concluded that neutrophil emigration into the intestinal lumen of piglets could occur in response to K88-positive E coli and resulted not from the presence or absence of the intestinal K88-receptor but from the ingestion of immune colostrum.     

Molecular characterization of a myosin alkali light chain-like protein, a "concealed" antigen from the hard tick Haemaphysalis qinghaiensis

There should be some differences between antibodies generated by feeding ticks on animals and those derived by immunizing animals with tick extracts. Here, we found serum collected from sheep immunized with Haemaphysalis qinghaiensis salivary gland extracts could detect two more protein bands with molecular weights of 22 and 37 kDa (P22 and P37) on Western blots of extracts of tick salivary glands than serum from tick infected animals. Rabbit anti-H. qinghaiensis differential protein immune serum was then generated from P22 and P37 and was used to immunoscreen a cDNA library constructed from salivary glands, Malpighian tubules and ovaries of partially engorged H. qinghaiensis. A cDNA contains an open reading frame of 483 bp that codes for 160 amino acid residues with a coding capacity of 18 kDa was cloned and designated Hq02. Expression analysis by RT-PCR showed that this gene is expressed in salivary glands, midguts, other organs and different developmental stages of H. qinghaiensis. The predicted amino acid sequence of the Hq02 gene had high homology to some known myosin alkali light chain (MLC) proteins. A fusion protein consisting of 130 amino acids of Hq02 protein and 335 amino acids of T7 gene 10 protein was expressed in Escherichia coli and used to immunize sheep. Western blot showed that only rabbit anti-H. qinghaiensis differential protein immune serum could recognize the expressed Hq02 protein, while rabbit anti-H. qinghaiensis saliva immune could not. This proved Hq02 protein was a "concealed" antigen. Immunization with the recombinant Hq02 conferred a 21.8% reduction of engorgement weight for adult female ticks that fed on the immunized sheep. This is the first report of tick myosin alkali light chain and the function of this protein is discussed.     

Evaluation of assays for the measurement of bovine neutrophil reactive oxygen species

During mastitis and other bacterial-mediated diseases of cattle, neutrophils play a critical role in the host innate immune response to infection. Neutrophils are among the earliest leukocytes recruited to the site of infection and contribute to host innate immune defenses through their ability to phagocytose and kill bacteria. The bactericidal activity of neutrophils is mediated, in part, through the generation of reactive oxygen species (ROS). Extracellular release of ROS can induce injury to host tissue as well, and aberrant release of ROS has been implicated in the pathogenesis of certain inflammatory-mediated diseases. Due to their essential role in bacterial clearance and implicated involvement in the pathogenesis of other diseases, there is much interest in the study of neutrophil-generated ROS. Several assays have been developed to measure ROS production, however, many of these have not been evaluated with bovine neutrophils. The objectives of the current study were to evaluate different assays capable of measuring bovine neutrophil ROS, and to compare the results of assays never previously tested with bovine neutrophils to those obtained from more well-established assays frequently used with these cells. Eight different assays were evaluated, including: luminol, isoluminol, and methyl cypridina luciferin analog (MCLA) chemiluminescence assays; Amplex Red, dihydroethidium (DHE), dichlorodihydrofluorescein diacetate (CM-H(2)DCFDA), and dihydrorhodamine 123 fluorescence assays; and the cytochrome c absorbance assay. The assays were evaluated in the context of their abilities to detect ROS produced in response to two agonists commonly used to induce neutrophil activation, phorbol 12-myristate, 13-acetate (PMA) and opsonized zymosan. Diphenyleneiodonium chloride, a NADPH oxidase inhibitor, was used to assess the specificity of the assays to detect ROS. The ability of these assays to discriminate between intra- and extracellular ROS and to specifically detect distinct ROS was evaluated using superoxide dismutase and catalase, which scavenge extracellular superoxide and hydrogen peroxide, respectively. With the exception of the DHE assay, all assays detected bovine neutrophil ROS generation elicited by PMA and zymosan. PMA, but not zymosan, was able to stimulate neutrophil generation of ROS at levels that were detectable with DHE. The MCLA chemiluminescence assay was the only assay that detected ROS produced in response to each of the lowest concentrations of PMA and zymosan tested. To our knowledge, this is the first study to evaluate DHE-, MCLA-, Amplex Red-, and isoluminol-based assays for the measurement of bovine neutrophil ROS, and the most comprehensive comparative study of ROS assays under similar experimental conditions.     

Haematological and biochemical values in horses naturally infected with Strongylus vulgaris

The concentrations of serum proteins (beta 1, beta 2, gamma, alpha 1, alpha 2 globulins and albumin) and absolute numbers of eosinophils, neutrophils and lymphocytes were examined in 64 naturally infected horses and ponies in which the number of larvae of Strongylus vulgaris in the cranial mesenteric artery and the severity of the lesion of verminous arteritis could be determined. The horses were grouped according to the number of larvae found and the severity of the arteritis. The results demonstrated that, although some significant deviation from a random distribution occurred in certain of the values (chi 2 test), there was considerable individual variation in the values obtained for individual animals within groups and overlap of the range of values between groups. Also the number of larvae present in the artery did not necessarily accurately reflect the severity of the arterial lesion. Thus, the parameters examined could not be used reliably to estimate the intensity of infection with S vulgaris in an individual animal.     

IgG antibody responses to an inhaled antigen in horses with "heaves" (recurrent airway obstruction).

A controlled experimental system for the evaluation of pulmonary immune responses in horses with "heaves" (recurrent airway obstruction) has been developed. We hypothesized that the humoral immune response to an inhaled antigen in diseased horses would be different from that of healthy horses and that chronic pulmonary inflammation would bias the production of IgG isotypes in diseased horses as compared to healthy horses. Healthy and affected horses were housed in a natural challenge environment (stabled, fed dusty hay) and exposed by inhalation, to a nebulized solution of keyhole limpet hemocyanin (KLH). Sera and bronchoalveolar lavage fluids (BALFs) were collected from horses prior to and following their inhalation exposure to the antigen. Differential cell counts were performed on the cells in the BALF. An enzyme-linked immunosorbent assay (ELISA) was used to determine the concentrations of IgGa, IgGb, IgG(T) and combined IgG specific for KLH in the sera and BALF. The percentages of neutrophils in the BALF of diseased horses were increased 4-6-fold over healthy horses. Combined IgG specific for KLH was significantly greater in BALF and serum from healthy compared to diseased horses. Differences in isotypes were also evident; however, only IgGb specific for KLH in the BALF was significantly increased in healthy versus diseased horses. Possible explanations for this difference include: (1) increased destruction of antigen before it could interact with lymphocytes, (2) down-regulation of IgGb production by inhibitory cytokines in diseased horses, or (3) binding of IgGb to Fc receptors on the large numbers of neutrophils in the lungs of diseased horses. In contrast to the prevailing notion that horses with heaves have exaggerated immune responses, our data suggest that diseased horses exposed to an aerosolized protein mount weaker IgG responses compared to healthy horses.     

Tissue strength and wound morphology of the equine linea alba after ventral median celiotomy

OBJECTIVE: To evaluate the tensile strength and wound morphology of the equine linea alba at intervals over 6 months after ventral median celiotomy. STUDY DESIGN: Linea alba tensile strength and wound morphology were determined at 2, 4, 8, 16, and 24 weeks postoperatively. Linea alba samples from 3 unoperated horses were used as controls. ANIMALS: Eighteen adult horses, weighing 400 to 500 kg, 4 to 15 years old. METHODS: Tensile strength and thickness of incised linea alba samples collected at 2, 4, 8, 16, and 24 weeks after ventral median celiotomy were compared with control linea alba samples. Additional samples were subjectively evaluated for wound morphology, notably collagen morphology. RESULTS: Control linea alba had a mean (+/-SEM) tensile strength of 484.9 +/- 58.3 N and was significantly (P < or = .05) stronger than at 2 weeks (87.7 +/- 61.4 N) after surgery. The tensile strength of 4-week (305.8 +/- 61.7 N), 8-week (465.4 +/- 56.5 N), and 16-week (477.8 +/- 57.2 N) samples were not significantly different from control linea alba. At 24 weeks, the tensile strength (721.0 +/- 57.9 N) was significantly stronger than control. The 2-, 4-, and 8-week samples were significantly thicker than controls, whereas the 16- and 24-week samples were not different from controls. On microscopy, control samples were characterized by dense mature collagen bundles. At 2 weeks, samples consisted primarily of granulation tissue, whereas at 4 weeks, samples had immature collagen fibers that were not formed into bundles, and at 8, 16, and 24 weeks, all samples had abundant mature collagen fibers formed into bundles. CONCLUSIONS: At 8 weeks, incised and sutured equine linea alba had a tensile strength comparable with non-incised linea alba and was characterized by mature collagen. CLINICAL RELEVANCE: Based on tensile strength and wound morphology, horses that have had an uncomplicated recovery after ventral median celiotomy should be able to return to controlled exercise as early as 60 days after surgery.     

Effects of midazolam on equine innate immune response: a flow cytometric study

Benzodiazepines (BDZ) are among the most frequently used class of psychotropic drugs employed in veterinary medicine in Brazil and worldwide due to their anxiolytic, muscle relaxant and anticonvulsant effects [J. Clin. Pharmacol. 33 (1993) 124]. Peripheral benzodiazepine receptor (PBR) sites were described in peripheral organs, endocrine steroidogenic tissues and immune organs and cells. Midazolam is a mixed-type agonist of PBRs. The present study is focused on the effects of midazolam on equine peripheral blood neutrophils, peritoneal macrophages and cortisol levels in plasma. Adult horses were treated with a single dose of midazolam (0.06 or 0.1 mg/kg) or with 0.9% NaCl. Immune cells were collected 24 h after treatment for flow cytometry analysis of Staphylococcus aureus-induced phagocytosis and oxidative burst. Plasma cortisol concentration was measured 30, 90, 180 and 360 min after midazolam treatment. Midazolam induced a dose-dependent reduction on: (1) peripheral blood neutrophil and peritoneal macrophage oxidative burst; (2) the capacity of both peripheral blood neutrophils and peritoneal macrophages to phagocyte S. aureus. Increments on plasma cortisol concentration were not found after 0.06 and 0.1 mg/kg of midazolam. The effects on oxidative burst of neutrophils and macrophages from horses treated with midazolam were interpreted as a consequence of an impairment of S. aureus-induced phagocytosis. The present data suggest that midazolam, most probably acting on PBRs present on equine macrophage and neutrophil membranes, might have changed some mechanisms related to both phagocytosis and oxidative burst. These results support the use of flow cytometry to identify functional properties and dysfunction of equine immune cells. They also confirm the notion that changes in the functional capacity of the immune system may represent an important hazard of exposure to drugs or chemicals.     

Study into wild Egyptian plants of potential medicinal activity. Ninth communication: hypoglycaemic activity of some selected plants in normal fasting and alloxanised rats

31 desert plants belonging to 17 families were collected from different Egyptian localities. 21 plants extracts were orally given to normal rats, and 15 were tested on fasted and to alloxanised rats. The results were compared with a standard oral hypoglycaemic drug (Daonil, Hoechst) used as a positive control. The following findings were obtained: 8 plants exhibited persistent hypoglycaemic effects, Lycium shawii, Salvia (S.) aegyptiaca, Pergularia tomentosa, Convolvulus (C.) althaeoides, Haloxylon salicornicum, Ephedra alata, Scrophularia deserti, and Crotalaria aegyptiaca. Transient hypoglycaemic effects appeared only 1 hour after administration in response to 4 plants, Silena succulenta, Lygos raetam, C. lanatus, and Pulicaria incisa. In the cases of Ochradenus baccatus and Zygophyllum album, slow hypoglycaemic activity was produced and appeared 3 hours after administration. 5 plants showed hypoglycaemic effects viz, Thymus capitatus, Launaea nudicaulis, Conyza dioscorides, Nitraria retusa, and Limonium tubiflorum. Among the 15 plant extracts tested on alloxanised diabetic rats only 4 showed hypoglycaemic effects more potent than those of the administered dose of Daonil. These were Matthiola livida, S. aegyptiaca, Astragalus species, and Arthrocnemum glaucum. The hypoglycaemic effect of S. aegyptiaca in fasting rats has been confirmed also in alloxanised diabetic animals. This emphasises the importance of conducting both experiments in order to obtain a reliable conclusion.