米非司酮486阻断鸡GR及其对地塞米松诱导的免疫抑制的逆转效应

本研究在应用 1 0 ,2 5 ,5 0 ,75 mg/ kg米非司酮阻断部分去除肾上腺鸡糖皮质激素受体 ( GR)的基础上研究了 2 5 mg/ kg和 5 0mg/ kg米非司酮对 1 0 ,2 5 ,5 0 ,75 mg/ kg地塞米松 ( Dex)引起的免疫抑制的逆转效应。结果显示 :2 5 ,5 0 mg/ kg米非司酮对 GR的阻断率可达 ( 39.2 5± 5 . 42 % )和 ( 74. 93±9.5 0 % ) ,为阻断鸡 GR提供了理想选择剂量。同时 2 5 mg/ kg米非司酮几乎可以完全逆转 1 0 ,2 5 ,5 0 mg/ kg Dex引起的脾细胞 IL - 2、IFN诱生活性 ,T、B细胞刺激增殖活性及淋巴器官体重比的下降 ;5 0 mg/ kg米非司酮可以部分逆转这些效应 ,并且还可阻断 Dex( 5 0mg/ kg以下剂量 )诱导的淋巴细胞凋亡。提示应用米非司酮部分阻断 GR可以逆转糖皮质激素 ( GC)诱导的免疫抑制效应 ,对畜禽应激性疾病的预防具有理论上的指导意义。     

中央杏仁核内微量注射地塞米松对NA／NPY在NTS所致心血管效应的影响

运用电生理学技术和心血管实验,观察了中央杏仁核(CeA)神经元与孤束核(NTS)神经元活动之间的相互作用,以及在CeA 内注射地塞米松(Dex)对NTS内去甲肾上腺素(NA)/神经肽Y(NPY)诱导的心血管效应的影响。电生理学实验显示,用L-谷氨酸兴奋CeA 神经元后,NTS内神经元活动主要呈现抑制反应(12/18);向NTS内注射NPY 后,CeA 内神经元活动也以抑制反应为主(13/23)。向CeA 内注射Dex,可以消除NTS内微量注射NA/NPY 所引起的降压和减慢心率效应。NA:动脉血压下降(- 0.37±0.25) kPa,心率下降(- 5±5) 次/m in,对照分别为(- 2.57±0.21) kPa,(- 33±11) 次/m in。NPY:(- 0.47±0.29)kPa,(- 10±8) 次/m in,对照(- 3.37±0.36) kPa, (- 50±9) 次/m in。由此表明,不仅CeA 与NTS在心血管活动调节中存在相互抑制作用,而且当CeA 受到高水平的糖皮质激素作用时,会抑制NTS内降压系统的作用。这可能是应激致发高血压的重要原因     

Bone development of suckling piglets after prenatal,neonatal or perinatal treatment with dexamethasone

In mammals, the release from growth‐inhibiting conditions results in catch‐up growth. To investigate animal evidence for whether prenatal dexamethasone (DEX) treatment leads to the development of growth restriction especially reduced mineralization of skeleton, and release from it leads to the phenomenon of catch‐up, piglets were prenatally exposed to DEX (3.0 mg/sow per day^?2) during the last 24 days of prenatal life and tested further in two different ways: discontinued at birth and continued administration of DEX (0.5 mg/kg day^?2) to piglets through 30 days of neonatal life. Using dual energy X‐ray absorptiometry methods, bone mineral density (BMD) and bone mineral content (BMC) were measured. The three‐point bending test was applied to determine the mechanical properties of the bones. Furthermore, geometric properties of the bones were assessed. Serum concentration of osteocalcin (OC) was determined. Histomorphological analysis of the ribs was also performed. The consequences of neonate DEX treatment and in utero DEX exposure were reflected in a dramatic decrease of BMD, BMC and blood serum OC concentration and geometric parameters of piglets’ bones. Prenatal action of DEX during the last 24 days of pregnancy resulted in continued neonatal modification of bone tissues, thus diminishing bone quality, and negatively influenced structural development and mechanical properties, finally increasing the risk of fractures of ribs and limb bones. Prenatal DEX treatment limited to the last 24 days of foetal life did not reduce the term birth weight and the growth of suckling piglets followed up to 30 days of neonatal life, and catch‐up in bone mineralization did not occur.     

Dexamethasone-induced exophthalmos in a group of Holstein calves

Six Holstein calves were evaluated for progressive exophthalmos. The affected calves were receiving daily injections of dexamethasone (30 microg/kg subcutaneously twice daily) as part of a metabolic study. The control calves did not exhibit exophthalmos. The ocular examinations were normal except for the exophthalmos, which ranged from mild to marked in severity. Upon postmortem examination, marked deposition of retrobulbar adipose tissue was noted in the affected calves. Dexamethasone administration appears to increase deposition of retrobulbar adipose tissue resulting in a progressive exophthalmos.     

The Effects of Dexamethasone on the Response of Bronchus-associated Lymphoid Tissue to Intranasal Administration of Formalin-killed Pasteurella haemolytica A2 in Goats

A trial was conducted to observe the immediate and chronic effects in goats of dexamethasone administration on the bronchus-associated lymphoid tissue (BALT) response to intranasal administration of formalin-killed Pasteurella haemolytica A2. Twenty-four goats were divided into four groups. Those in group 1 were injected intramuscularly with 1 mg/kg dexamethasone on three consecutive days, followed by intranasal exposure to formalin-killed P. haemolytica A2 one day after the last dexamethasone treatment. The goats in group 2 were similarly injected with dexamethasone followed by intranasal exposure to formalin-killed P. haemolytica A2 21 days after the last dexamethasone treatment. The animals in group 3 were exposed intranasally to formalin-killed P. haemolytica A2 without prior dexamethasone treatment. The animals in group 4 were untreated controls. The intranasal exposures to formalin-killed P. haemolytica A2 were repeated 2 weeks later. Intranasal exposure to formalin-killed P. haemolytica 1 day after dexamethasone treatment further reduced the number and size of BALT compared to the untreated control. Significantly (p<0.01) more reduction of BALT occurred in goats exposed to formalin-killed P. haemolytica A2 21 days after dexamethasone treatment. On the other hand, intranasal exposure of goats without prior dexamethasone treatment stimulated the BALT compared to the untreated controls.     

醋酸可的松和地塞米松诱发野鼠卡氏肺孢子虫肺炎的试验研究

采用16只褐家鼠、30只黄胸鼠和20只小家鼠经皮下注射醋酸可的松和地基米松12周，建立野鼠卡氏肺孢子虫肺炎模型。经剖捡，取肺组织制备涂片、印片和切片，用不同染色液染色后，进行病原体形态观察。结果表明：黄胸鼠卡氏肺孢子虫感染率最高，为100％；褐家鼠感染率次之，为81．25％；小家鼠最低，为65％；注射醋酸可的松的诱导率高于地塞米松的诱导率。支气管灌洗液涂片和肺组织印片用姬姆萨染色后，可见卡氏肺孢子虫的囊内小体和滋养体；肺组织印片和切片用哥氏银、甲苯胺蓝染色后，可见清晰的卡氏肺孢子虫的包囊壁。     

Peripheral plasma levels of estrone and progesterone in pregnant pigs treated with dexamethasone

Five pregnant pigs of the Swedish Landrace Breed were treated with dexamethasone i.m. injections during early and late pregnancy. The daily dose of dexamethasone was never more than 100 mg. There were no significant changes in the maternal plasma levels of estrone and progesterone during dexamethasone injections. The dexamethasone initiated neither abortion nor parturition.     

Effect of an Immunosuppressor (Dexamethasone) on <Emphasis Type="Italic">Eperythrozoon</Emphasis> Infection

The aim was to study the relationship between the infection rate of Eperythrozoon suis and the status of the immune system. Four pigs with chronic eperythrozoonosis were divided into experimental and control groups. Immunosuppression of the experimental group was accomplished by injecting with high-dose glucocorticoid (dexamethasone) on 3 consecutive days. Microscopic examination of blood smears was performed to observe the change of infection rate after administration. The blood samples of each group were collected on day 7 after administration for half-nested PCR assay. The microscopic results showed that the infection rate of the experimental group rose distinctly by 40 h late and remained at 90% in the days following administration. No changes were observed in the control group. PCR results showed a single expected 250 bp fragment in each group, which validated the positive microscopic results. This study demonstrated the significant effect of dexamethasone (DEX) on Eperythrozoon infection.     

高三尖杉酯碱联合地塞米松防治翼状胬肉的临床及病理研究

目的：了解术前局部注射高三尖极酯碱联合地塞米松对减少翼状胬肉术后复发的效果。方法：将７２例翼状胬肉患者分为两组,治疗组４２例４２眼,术前７、３及１ｄ翼状胬肉局部注射１．８×１０＾－４ｍｏｌ／Ｌ高三尖杉酯碱０．２ｍＬ加９．６８×１０＾－２ｍｏｌ／Ｌ地塞米松０．２ｍＬ的混合液共约０．４ｍＬ,对照组３０例３０眼术前不用药。分别观察术后眼部反应、复发率及行增殖细胞核抗的（ＰＣＮＡ）免疫组化研究。结果：平均     

液相色谱-电喷雾串联四极杆质谱法同时测定牛肉中地塞米松、倍他米松和倍氯米松残留

【研究目的】建立一种可检测实际牛肉样品中地塞米松、倍他米松和倍氯米松药物残留的液相色谱-电喷雾串联四极杆质谱方法;【方法】样品在碱性条件下经乙酸乙酯提取,正已烷脱脂,通过MCX固相萃取小柱净化后,进行液相色谱-质谱分析。采用Xterra MS C18色谱柱,以均含1％甲酸的乙腈和水为流动相做梯度洗脱;【结果】方法的检出限和定量限为0．5μg／kg和2．0μg/kg,三种药物添加水平为0．5、2和50μg／kg时。方法的回收率在77．6％～97．9％之间,批内变异系数为2．5％～7．9％,批间变异系数为3．10%～8．7％;【结论】所建方法简便快速,可用于实际应用。