Evaluation of neutrophil function in female goats

Polymorphonuclear neutrophils (PMN) were isolated from the blood of healthy adult female goats on each of 3 consecutive days. The PMN isolated were evaluated, using random migration, chemotaxis, Staphylococcus aureus ingestion, cytochrome C reduction, iodination, and antibody-dependent cell-mediated cytotoxicity assays. Over the 3 days, mean values for each of the assays ranged as follows: area of random migration, 11.3 to 19.9 mm2; chemotactic index, 6.4 to 11; chemotactic difference, 2.8 to 4.2 mm; S aureus ingestion, 18.3% to 26.1% ingested; cytochrome C reduction, 2.7 to 3.2 nmoles of O2- produced/well; iodination, 19.4 to 25.1 nmoles of NaI/10(7) PMN/h; and antibody-dependent cell-mediated cytotoxicity 59% to 90% 51Cr released. Significant (P less than 0.05) day-to-day variations were found for all assays. Parallel increases and decreases for all test results on a per day basis indicated a common denominator influencing cell functional status rather than variability inherent in the assays themselves. Alterations induced in the cells during the cell isolation procedure were considered a probable cause.     

Effect of levamisole on lymphocyte blastogenesis and neutrophil function in dexamethasone-treated cattle

Levamisole was evaluated at 6 dose levels for its ability to prevent the dexamethasone-induced suppression of in vitro lymphocyte blastogenesis or neutrophil function in cattle. Dexamethasone (0.4 mg/kg of body weight, IM) and levamisole hydrochloride (0.5, 1.0, 2.0, 4.0, or 8.0 mg/kg orally) were administered to groups of 4 cattle daily for 3 days. Another group of 4 cattle were given the 3-day dexamethasone treatment and 6.0 mg/kg of levamisole (the recommended anthelmintic dose) was given only once on the 1st day that dexamethasone was given. Results obtained from the dexamethasone-levamisole-treated cattle were compared with results obtained from cattle that were given only dexamethasone. Levamisole had no apparent consistent ability to enhance lymphocyte blastogenic responsiveness (to the mitogens phytohemagglutinin, concanavalin A, or pokeweed mitogen or in a 1-way mixed lymphocyte reaction) or to enhance neutrophil function (random migration, nitroblue tetrazolium reduction, iodination, or antibody-dependent cell-mediated cytotoxicity) in dexamethasone-treated cattle.     

地塞米松对山羊皮质醇分泌和瘤胃生物钟基因表达的影响

为了研究地塞米松对山羊皮质醇分泌和瘤胃生物钟基因表达的影响,试验选用10只装有永久性瘤胃瘘管的波尔杂交山羊,随机分为对照组(n=5)和地塞米松组(n=5),对照组注射生理盐水,地塞米松组注射地塞米松(0.2 mg/kg),每天注射1次,连续注射21 d。试验结束后,采集血液和瘤胃组织;放射免疫分析法(radioimmunoassay,RIA)检测血浆皮质醇含量;Real-time PCR检测瘤胃生物钟基因表达量。结果显示:与对照组相比,地塞米松组血浆皮质醇浓度显著降低(P0.05),瘤胃液中皮质醇浓度无显著变化(P0.05),瘤胃上皮组织中永恒蛋白基因(Tim)和肌肉芳香烃受体核转运样蛋白1(Bmal1)mRNA表达显著上调(P0.05);相关性分析结果显示:血浆皮质醇浓度与瘤胃上皮组织中Tim(R=-0.64,P=0.08)和Bmal1(R=-0.62,P=0.09)mRNA表达呈负相关趋势,瘤胃中皮质醇浓度与瘤胃上皮组织中Bmal1 mRNA表达呈显著负相关(R=-0.84,P0.05)。结果提示,外源性地塞米松降低山羊体内内源性皮质醇的生成,上调瘤胃上皮组织中生物钟基因的表达,且生物钟基因表达水平与血液、瘤胃液中皮质醇浓度呈高度负相关。     

Immunosuppression in goats by dexamethasone and cyclophosphamide

The influence of dexamethasone and cyclophosphamide on the goat immune system was investigated. Seven goats, with a previous contact with caprine herpesvirus type 1 (CHV-1), were used. All had been vaccinated with live Mycobacterium paratuberculosis vaccine.

Six goats were injected intravenously (i.v.) with dexamethasone daily for 5 days (2.5–4 mg/kg BW per day). Three also received 25 mg/kg BW of cyclophosphamide on day 0. The seventh goat was not treated.

Dexamethasone alone caused depression, slight lymphopenia and fall in tuberculin reaction. Dexamethasone plus cyclophosphamide caused a severe clinical reaction, marked leukopenia (lymphopenia), fall in tuberculin reaction and significant increase in CHV-1 neutralizing antibody titres. M. paratuberculosis antibody reaction was variable and thus difficult to be assessed. CHV-1 was not isolated.     

Effects of photoperiod on the secretion of growth hormone in female goats

The aim of the present study was to clarify the effect of photoperiod on the secretion of growth hormone (GH) in goats. Adult female goats were kept at 20°C with an 8‐h or 16‐h photoperiod, and secretory patterns of GH for 4 h (12.00 to 16.00 hours) were compared. In addition, the goats were kept under a 16‐h photoperiod and orally administered saline (controls) or melatonin, and the effects of melatonin on the secretion of GH were examined. GH was secreted in a pulsatile manner. There were no significant differences in pulse frequency between the 8‐ and 16‐h photoperiods; however, GH pulse amplitude tended to be greater in the group with the 16‐h photoperiod (P = 0.1), and mean GH concentrations were significantly greater in the 16‐h photoperiod (P < 0.05). The GH‐releasing response to GH‐releasing hormone (GHRH) was also significantly greater for the 16‐h photoperiod (P < 0.05). There were no significant differences in GH pulse frequency between the saline‐ and melatonin‐treated groups. However, GH pulse amplitude and mean GH concentrations were significantly greater in the saline‐treated group (P < 0.05). The present results show that a long photoperiod enhances the secretion of GH, and melatonin modifies GH secretion in female goats.     

Toxicity and tissue residue depletion of levamisole hydrochloride in young goats

Toxicity and tissue residue depletion studies were conducted in young goats, using an oral drench formulation of levamisole hydrochloride. In the target animal toxicity study, 3 groups of 5 goats each were given levamisole orally to provide approximately 11.88, 23.76, or 35.64 mg of levamisole HCl/kg/d for 3 consecutive days; a fourth group of 5 goats served as untreated controls. Blood samples were taken for analysis of levamisole 1 day prior to dosing and 1, 2, 3, 4, and 7 days following the third dose. At the 35.64-mg/kg dose, 2 of 5 goats responded with typical cholinergic signs of toxicosis on each of the 3 days of dosing. The times for the onset of clinical signs of toxicosis ranged from 18 to 63 minutes, with an average duration of 32 minutes. Administration of 23.76 mg of levamisole HCl/kg resulted in hyperactive behavior in 1 of 5 goats only on the first day of dosing; no abnormal behavior was observed in any of the 5 goats following the second or third dose of levamisole HCl at 23.76 mg/kg. Untoward effects were not seen in the 5 goats dosed at 11.88 mg of levamisole HCl/kg or in the controls during the 3-day dosing period or in the following 7-day observation period. Overall, the observed signs of toxicosis did not become more severe, affect more goats, or persist for a longer period on subsequent dosing days.(ABSTRACT TRUNCATED AT 250 WORDS)     

Alteration of neutrophil function associated with coccidiosis in cattle: influence of decoquinate and dexamethasone

Twenty Holstein steers subclinically infected with coccidia were allotted to 2 groups of 10 steers each. One group received a diet containing 0.5 mg of decoquinate/kg of body weight. After 25 days on the diet, there was no difference between the groups in lymphocyte blastogenic responsiveness to mitogens; however, there were differences in neutrophil function. Lymphocytes from steers of the decoquinate-fed group had decreased random migration under agarose, enhanced cytochrome C reduction, and enhanced iodination activity. Other measures of neutrophil function evaluated (chemotactic index, Staphylococcus aureus ingestion, and antibody-dependent and -independent cell-mediated cytotoxicity) were not affected. After 30 days of decoquinate feeding, half of the cattle in each group received 5 daily IM injections of dexamethasone (0.04 mg/kg of body weight). The dexamethasone-treated steers from the group that did not have decoquinate in the diet developed clinical coccidiosis, whereas the decoquinate-treated steers remained clinically normal. Lymphocyte and neutrophil function were again evaluated for a 3-day period beginning 4 days after dexamethasone treatment was halted. Neutrophils from the steers that developed clinical coccidiosis after dexamethasone administration had significantly (P less than 0.05) inhibited random migration under agarose, cytochrome C reduction, and iodination activity, but significantly (P less than 0.01) enhanced S aureus ingestion. The feeding of decoquinate prevented the inhibition of neutrophil cytochrome C reduction and lessened the inhibition of neutrophil iodination in the dexamethasone-treated group. Dexamethasone treatment was associated with an inhibition of lymphocyte blastogenic responsiveness to phytohemagglutinin in principals as well as controls.     

Effects of female sex hormones on uterine motility and reactivity to oxytocin in goats.

Uterine motility was recorded for several weeks in 10 ovariectomised goats, using small intra-uterine balloons, to study the effects of female sex hormones on uterine activity and reactivity to oxytocin. Oestradiol stimulated uterine contractions and increased both the sensitivity and intra-uterine pressure response to oxytocin. When progesterone was administered in addition to oestradiol, spontaneous uterine motility became irregular with low amplitude contrations; the sensitivity and reactivity to oxytocin was significantly depressed.     

Efficacy of levamisole against immature and mature nematodes in goats with induced infections

Anthelmintic efficacy of levamisole against induced infections with 7- and 21-day-old Haemonchus contortus, Ostertagia circumcincta, Trichostrongylus axei, and T colubriformis was evaluated as an oral drench in goats. Group 1 (n = 8) was not treated, group 2 (n = 8) was given 3.96 mg of levamisole/kg of body weight, group 3 (n = 8) was given 7.92 mg of levamisole/kg, and group 3 (n = 7) was given 11.88 mg of levamisole/kg. Efficacy against all worms was low in goats given 3.96 mg of levamisole/kg, but was high against adult H contortus (99%) and adult T colubriformis (99.7%) in goats given 7.92 mg of levamisole/kg. Although efficacy against adults of all species was high in goats given 11.88 mg of levamisole/kg, some immature worms of all species remained in the abomasa of goats.     

不同CO2气腹压对山羊肝、肾功能的影响

选择21只健康山羊随机均分为A、B、C 3组。分别用1.33、2.0、2.4kPa的气腹压值进行充气腹试验,以探讨不同CO2气腹压对山羊肝、肾功能的影响。结果表明:CO2气腹压可引起ALT、AST、ALP、Tbil、Crea升高和U-rea降低;在放气后1或2、3 d时,B、C 2组与A组相比较对肝、肾功能的影响差异显著;在放气后4d,A组肝、肾功能基本能恢复到气腹前水平,B、C 2组放气后4d尚未恢复到气腹前水平。当气腹压≥1.06 kPa时,均能够保证山羊的腹腔充分膨胀隆起。本试验确定了在山羊腹腔镜手术充气腹时,应选用1.06kPa≤PP≤1.33kPa气腹压值为宜,从而为今后开展山羊腹腔镜手术奠定了理论基础。     

Effects of pentoxifylline on equine neutrophil function and flow properties.

Pentoxifylline has been reported to improve peripheral vascular circulation by altering the flow properties of blood. To determine if the hemorrheological effects of pentoxifylline were mediated by alterations in neutrophil function and/or flow properties, we evaluated the drug's effects on equine neutrophils in vitro. Pentoxifylline, at a concentration of 1 x 10(-1) M, but not at concentrations of 1 x 10(-6) M to 1 x 10(-2) M, markedly suppressed neutrophil superoxide production, zymosan phagocytosis and adherence to nylon wool. Pentoxifylline failed to improve neutrophil filterability through 3 mu polycarbonate filters at any concentration tested. We conclude that equine neutrophil function and flow properties are unlikely to be affected by pentoxifylline concentrations achievable in vivo.     

Effects of photoperiod on the secretion of growth hormone and prolactin during nighttime in female goats

The aim of the present study was to clarify the effect of photoperiod on nighttime secretion of growth hormone (GH) in goats. Adult female goats were kept at 20°C with an 8 h or 16 h dark photoperiod, and secretory patterns of GH for 8 h in the dark period were examined with the profile of prolactin (PRL) secretion. GH was secreted in a pulsatile manner in the dark period. There were no significant differences in pulse frequency between the 8‐ and 16‐h dark photoperiods; however, pulse amplitude tended to be greater in the group with the 16‐h dark photoperiod (P = 0.1), and mean GH concentrations were significantly greater in the same photoperiod (P < 0.05). PRL secretion increased quickly after lights off under both photoperiods. The PRL‐releasing responses were weaker in the 8‐h than 16‐h dark photoperiod. The secretory response to photoperiod was more obvious for PRL than GH. The present results show that a long dark photoperiod enhances the nighttime secretion of GH in female goats, although the response is not as obvious as that for PRL.     

Use of dexamethasone for induction of parturition in goats

Parturition was induced in 5 goats of Beetal and Beetal x Black Bengal cross in advanced stages of pregnancy, using intramuscular injection of 10 mg of dexamethasone. Goats required 47.7 +/- 1.26 hours on average after injection for parturition. There were no deleterious effects of induction on placental expulsion, kid weight, kid survival, and postpartum fertility of does. Plasma concentrations of progesterone and oestradiol 17 beta followed a similar trend in controls and treated animals. While plasma progesterone concentrations declined before parturition, the oestradiol concentration rose to its peak on the day of parturition.     

Effects of human IL-8 isoforms on bovine neutrophil function in vitro

Interleukin 8 (IL-8) is a potent chemotactic and activating agent for human neutrophils and bovine IL-8 is chemotactic for bovine neutrophils; however, it is unclear whether IL-8 activates bovine neutrophils. Two isoforms of human recombinant (hr) IL-8 protein (77 and 72 amino acid) were used to stimulate bovine neutrophils in vitro. Bovine neutrophils exhibited significant migration in the presence of 0.1, 0.5, 1.0 and 5.0ngml(-1) hr IL-8 when incubated for 30min at 37 degrees C in a modified Boyden chamber assay. Both the 77 and 72 aa forms were equally effective in inducing migration in this assay. At the highest doses of IL-8 examined (1 and 5ngml(-1)), migration was similar to migration in the presence of 20% zymosan-activated serum (ZAS) or 12h lipopolysaccharide (LPS)-stimulated blood monocyte supernatants (CM). Significant (p<0. 05) release of alkaline phosphatase (ALK-P) (from specific granules) occurred but myeloperoxidase (MPO) release and superoxide anion production were not enhanced in bovine neutrophils by either form of hrIL-8 at any of the doses tested. Significant (p<0.05) alkaline phosphatase release was observed in the presence of 10 and 100ngml(-1) for the 72 aa form of IL-8 and only at the higher dose for the 77 aa form of IL-8. The ZAS and CM significantly enhanced neutrophil degranulation of ALK-P and MPO as well as inducing superoxide anion production. These results suggest that IL-8 may play a role in both neutrophil recruitment and activation during bovine inflammatory processes.