东北梅花鹿配种后主要生殖激素变化

采集4头体况良好、健康、配种后梅花鹿的血样,用RIA分析方法对血清中的5种生殖激素(LH、FSH、E2、P4和hCG)的含量进行测定.结果表明:在配种后(第2～38 d)LH含量缓慢地降低,处于较低的水平,平均为29.97±32.70 mIU/mL;FSH的含量稳步上升,平均为1.60±0.66 mIU/mL;E2的含量除了一个较大的峰值(10.20±6.59 pg/mL)外,一直在降低,平均值是6.47±4.28 pg/mL;P4的含量平均为0.05±0.04 ng/mL;hCG的含量呈缓慢下降趋势,平均为22.71±26.48 mIU/mL.     

枫泾和长白青年母猪首次发情周期内血清中5种生殖激素含量变化

放射免疫法测定枫泾(FJ)和长白(L)青年母猪(各4头)首次发情周期内外周血清中促卵泡素(FSH)、促黄体素(LH)、17β-雌二醇(E_2)、孕酮(P_4)、和睾酮(T)的含量。测定结果,初情期开始日龄FJ猪平均为104.3±11.50天,L猪为235.0±1.95天。两猪种首次发情周期内外周血清中同种生殖激素有相似的变化趋势。在首次情期内,FJ和L猪的FSH平均含量分别波动在28.6±8.6～49.4±6.0ng/ml和16.8±2.5～38.9±0ng/ml之间;FSH总平均含量FJ猪组(37.8±2.7)显著高于L猪(27.0±3.1ng/ml)P<0.05;FJ猪发情0～2小时的FSH平均含量(34.4±2.1ng/ml)极显著地高于L猪(22.2±1.7ng/ml)P<0.001。排卵前LH峰均值FJ猪组(5.31±0.75ng/ml)显著高于L猪组(1.83±0.75ng/ml)P<0.05。发情当天(0天)E_2达峰值,FJ和L猪组分别是30.5±3.9和20.4±5.3pg/ml,两者无显著差异(P>0.05)。FJ和L猪组各自的P_4(ng/ml)和T(pg/ml)分泌呈显著正相关,相关系数依次为γ_F=0.71,P<0.05,γ_L=0.95,P<0.01。LH、FSH的含量高很可能是FJ猪高排卵率的重要因素之一。     

母犬发情周期血中生殖激素变化规律的研究

为研究自然发情和诱导发情的母犬发情期体内促卵泡素(FSH)、促黄体生成素(LH)、雌二醇(E2)和孕酮(P4)的分泌规律,将25只母犬随机分成2组:对照组为自然发情组,试验组为诱导发情组。对6只自然发情母犬和5只诱导发情母犬采血制备血浆,放射免疫分析法(RIA)测定FSH、LH、E2、P4的含量,采血时间为出现发情表征的第1、3、5、6、7、8、9、10、11、13、17、24天。对照组母犬FSH、LH和E2最低含量均值分别为(4.35±1.98)ng/m L、(4.95±2.22)ng/m L和(1.33±1.04)pg/m L,FSH、LH和E2峰值均值分别为(134.44±20.97)ng/m L、(117.56±17.49)ng/m L和(6.22±2.16)pg/m L,P4含量均值变化范围是(0.24±03)~(12.51±1.76)ng/m L;试验组母犬FSH、LH和E2最低含量均值分别为(4.19±2.12)ng/m L、(5.64±3.84)ng/m L和(1.57±0.76)pg/m L,FSH、LH和E2峰值均值分别为(172.98±56.40)ng/m L、(159.12±35.87)ng/m L和(6.08±1.16)pg/m L,P4含量均值变化范围是(0.24±0.06)~(12.51±3.95)ng/m L。结果表明:自然发情和诱导发情的母犬体内LH、FSH、E2和P4变化比较复杂,但仍有规律可循;E2对FSH的分泌具有一定的抑制作用,P4的含量变化在LH峰后的显著变化,P4稳定性和规律性更强;外源性PG-CI和FSH激素诱导发情的母犬的方法显著性提高了整个发情周期LH和FSH水平(P0.05),而对发情周期内E2和P4分泌水平均没有显著性影响(P0.05)。     

牦牛发情周期和妊娠早期乳脂孕酮水平的变化

采用放射免疫分析法对牦牛发情周期和妊娠早期的乳脂孕酮水平进行了测定,并对应用乳脂孕酮测定进行耗牛早期妊娠诊断的方法作了探讨。4头牦牛发情周期乳脂孕酮水平的变化类型与奶牛基本相似。发情期的乳脂孕酮含量低,为0.10±0.01(S.E.)ng/10μl;发情终止后4～5天,孕酮含量开始显著升高(P<0.01),并分别于周期第16,17,21和22天(周期长度分别为20、24、25、27天)达到峰值,平均为1.69±0.10(S.E)ng/10μl,下次发情前2天孕酮含量急剧下降到较低水平,于下次发情时重返到基础水平。15头牦牛妊娠12—30天的乳脂孕酮含量维持较高水平,平均为2.18±0.05(S.E)ng/10μl,妊娠18、20、22、24、26、28和30天的孕酮含量极显著高于8头未孕牛授精后相应各天的孕酮含量(P<0.01)。根据配后16和24天两份乳样的乳脂孕酮含量诊断怀孕与未孕的准确率分别为78.9%(15/19)和100%(11/11)。     

配种时间对母羊妊娠期生殖激素与生长激素的影响

为研究不同月份配种奶山羊妊娠期外周血中生殖激素与生长激素的变化规律,随机选择8月、10月、12月、翌年2月妊娠的关中奶山羊各10只,分别于配种后20d、75d、130d及分娩时采集其静脉血并分离血清,采用ELISA试剂盒检测血清中雌激素(E_2)、孕酮(P_4)、促卵泡生成素(FSH)、促黄体素(LH)、催乳素(PRL)和生长激素(GH)水平变化规律。结果表明,不同季节怀孕奶山羊在整个妊娠期间,同种激素的变化趋势一致,随着妊娠时间的延长,外周血中E_2、P_4、PRL和GH含量逐渐升高,FSH和LH含量递减,分娩前E_2和P_4含量下降,LH回升,FSH仍然下降,PRL和GH继续上升。不同月份妊娠期间外周血中E_2、P_4、FSH、LH、PRL、GH的均值变化范围分别为17.45~52.90ng/L,1899.39~6305.63pmol/L,4.45~6.99IU/L,142.33~207.09pg/L,367.37~626.88ng/L,15.55~28.71μg/L,奶山羊妊娠月份的不同对其激素水平有一定影响,但影响不大。说明奶山羊在不同月份配种妊娠后对其生殖内分泌无显著影响。     

促性腺激素(FSH、LH)对牛腔前卵泡体外发育及E_2分泌的影响

利用McCoy's 5a基础无血清培养系统研究了促卵泡素(FSH)、促黄体素(LH)2种促性腺激素对牛腔前卵泡的体外生长、存活及雌二醇(E2)分泌的影响.结果显示,培养液中单独添加LH对牛腔前卵泡生长影响不大,而单独添加50、100μg/L以上FSH对牛腔前卵泡直径增长和培养后期体外存活有明显的促进作用;当培养液中有10 μg/L LH存在时,2种促性腺激素协同刺激卵泡生长的作用更加明显.添加10 μg/L LH 50μg/L FSH对腔前卵泡体外生长、发育、存活及E2分泌均具有显著的促进作用(P<0.05).     

东北梅花鹿发情期血浆中LH,雌二醇含量变化

本文用放射免疫测定法测定了5头发情期东北梅花鹿血浆中促黄体素(LH)和17β-雌二醇的含量。所得结果:LH在发情前(0.288～0.321ng/ml血浆)与发情后(0.364～0.841ng/ml血浆)都处于低稳水平(P>0.05),但发情时出现非常显著的高峰(2.742ng/ml)(P<0.01);雌二醇在整个发情前后没有出现显著的高峰(P>0.05),仅在发情前约24小时发现一小峰(16.4±4.4pg/ml血浆),发情后12小时发现一小峰(24.9±6.1pg/ml血浆)。结果表明,东北梅花鹿发情期血浆LH、雌二醇含量的时相变化与其他已研究过的鹿种及一些反刍家畜基本一致。     

蓝狐阴茎化学成分的研究

应用放射免疫测定技术及激光速率散射比浊法对蓝狐阴茎中某些化学成分进行测定分析 ,得出与蓝狐生殖有关的睾酮 (T)、孕酮 (P)、17β -雌二醇 (E2 )、生长激素 (GH)、人绒毛膜促性腺激素 (HCG) ,其含量分别为 (2 0 5 0± 3 6 5 )ng/g、(0 6 7± 0 12 )ng/g、(99 2 5± 9 87)pg/g、(18 2 1± 2 98)ng/g、(4 5 6 3± 5 2 9)mIU/g ,得出与蓝狐生命活动有关的三碘甲状腺原氨酸 (T3 )、四碘甲状腺原氨酸 (T4)、生物信使cAMP、cGMP及免疫球蛋白IgA、IgG、IgM等成分含量分别为 (1 17± 0 17)ng/g、(2 6 13± 3 6 6 )ng/g、(2 1 39± 2 89)ng/g、(2 7 75±3 18)ng/g、(0 0 8± 0 0 1)mg/g、(0 0 7± 0 0 2 )mg/g、(0 0 4± 0 0 1)mg/g。     

枫泾公猪初情期前后外周血清中睾酮、促黄体素及皮质醇的含量变化

用放射免疫法测定并研究了在初情期间24小时内和交配过程中的3头枫泾公猪外周血清促黄体素(LH)、睾酮(T)和皮质醇(F)的含量及分泌范型。3头公猪平均于102日具有射精能力,开始进入初情期。初情期前(76～88日龄)T和LH含量较低,其平均值分别为1.28±0.44和1.57±0.09ng/ml。102日龄后,T含量迅速升高,平均为8.43±0.87ng/ml,与初情期前比较,差异极显著,(P<0.01);LH也随之升高,平均为2.04±0.15ng/ml,但前、后差异不明显(P>0.05)。初情期间24小时内,LH含量波动在1.04±0.40～2.25±0.87ng/ml之间,总平均为1.64±0.28ng/ml;T和F均呈突发性分泌方式,总平均值分别为4.32±1.49和14.79±9.61ng/ml,二者的分泌呈极显著正相关(r=0.88)。T和F的含量早上显著高于夜间(24点)。3头公猪在106日龄分别与发情母猪交配过程中,三种激素均处于较高水平,射精阶段T值显著高于爬下后5～6分钟的值,而LH和F值无显著变化。综上所述,初步揭示枫泾公猪平均于108日龄已建立睾酮、促黄体素和皮质醇性成熟的分泌范型。     

激素对猪卵母细胞体外成熟及孤雌胚胎发育的影响

为研究不同激素及其组合在猪卵母细胞体外成熟及对其后孤雌胚胎发育的影响,我们对比了孕马血清促性腺激素(PMSG)与人绒毛膜促性腺激素(hCG)组合、卵泡刺激素(FSH)与促黄体素(LH)组合、雌二醇(E2)及这些卵母细胞经孤雌激活后囊胚率的影响;以及不同FSH和LH浓度组合对猪卵母细胞体外成熟率。结果表明,在卵母细胞体外成熟液中添加10 U/mL PMSG和10 U/mL hCG的成熟率和孤雌囊胚率都达到最高(85.9%和55.3%);FSH与LH的组合次之,分别为77.1%和53.5%;E2最差,成熟率仅为54.0%囊胚率为19.5%。而在FSH与LH不同浓度配比中以10 U/mL FSH和20 U/mL LH时,猪卵母细胞成熟率最高达到80.9%。     

Induced abortion with two Prostaglandin F2α analogues in mares: Plasma progesterone changes

Three experiments were conducted to test the abortifacient effects of PGF2α analogues on mares during midgestation (average gestation length 141.5 days). The progesterone concentration was measured by radioimmunoassay. In experiment I, five mares recieved an injection of PGF2α analogue (fluprostenol: 500 μg intramuscularly) and a second injection either at 24, 48, of 72 h. Although the progesterone concentration decreased (P < 0.05) an average of 44 per cent in 24 h, none of the pregnancies were terminated. In experiment 2, beginning at least 10 days after experiment I, the same five mares were given PGF2α analogue as follows: 250 μg intravaginally and 500 μg intramuscularly. The treatment was repeated 48 h later. Progesterone concentrations had not increased since experiment 1 and dit not decrease during the 48 h following either injection. In experiment 3, six mares (average gestation length 162 days) were treated every 6 or 12 h with PGF2α analogue (cloprostenol: 375 μg) until expulsion of the fetus occurred at 47 ± 25 h after the initial injection; the mares received an average of 5 treatments. The progesterone concentration averaged 22 ± 7 ng/ml before the initial PGF2α treatment, decreased (P<0.05) to 8.4 ±2.7 ng/ml by 12 h before expulsion and 1–8 ±0.4 ng/ml 12 h after fetal expulsion. The progesterone concentration remained below 1.0 ng/ml for the next 4 days. However, only one of six mares exhibited estrual behavior after induced abortion.     

Pharmacokinetic Profile of Erythromycin after Intramammary Administration in Lactating Dairy Cows with Specific Mastitis

The pharmacokinetics of erythromycin was studied in five lactating dairy cows following single intramammary infusion of 300 mg erythromycin in each of two quarters per cow with specific mastitis. Levels of erythromycin in plasma and quarter milk samples were measured by agar plate diffusion assay using Micrococcus luteus (ATCC 9341) as the test organism. Erythromycin level in plasma reached a peak concentration value (C _max) of 0.07 ± 0.01 μg/ml at 30 min; thereafter, levels declined gradually to reach 0.05 ± 0.00 μg/ml 12 h post drug administration. The pharmacokinetic profile of the drug revealed mean absorption half life (t _1/2ka) as 0.26 ± 0.05 h. The drug was eliminated slowly with elimination half-life (t _1/2β) of 13.75 ± 0.35 h and elimination rate constant (k _el) of 0.04 ± 0.00 h⁻¹. The volume of distribution based on the zero-time plasma concentration intercept of the least-squares regression line of the elimination phase (V _d(B)) was 0.032 L/kg. The drug crossed to untreated quarters also; mean drug levels of 0.20 ± 0.07, 0.23 ± 0.07, 0.17 ± 0.04, and 0.17 ± 0.04 μg/ml were found at 3, 6, 8 and 12 h, respectively. The mean drug concentration for treated quarters was measured as 22.97 ± 2.31 μg/ml milk at first milking (12 h) following drug infusion. No apparent adverse reaction was seen in cows administered erythromycin. It is concluded that following intramammary infusion erythromycin diffuses readily and extensively in various body fluids and tissues and adequate concentration is maintained in udder tissues for at least 12 h post intramammary administration. Thus, erythromycin may be recommended for local therapy of acute mastitis caused by Gram-positive bacteria in lactating dairy cows.     

Pharmacokinetics and bone tissue concentrations of lincomycin following intravenous and intramuscular administrations to cats

Albarellos, G. A., Montoya, L., Denamiel, G. A. A., Velo, M. C., Landoni, M. F. Pharmacokinetics and bone tissue concentrations of lincomycin following intravenous and intramuscular administrations to cats. J. vet. Pharmacol. Therap.  35 , 534–540. The pharmacokinetic properties and bone concentrations of lincomycin in cats after single intravenous and intramuscular administrations at a dosage rate of 10 mg/kg were investigated. Lincomycin minimum inhibitory concentration (MIC) for some gram‐positive strains isolated from clinical cases was determined. Serum lincomycin disposition was best‐fitted to a bicompartmental and a monocompartmental open models with first‐order elimination after intravenous and intramuscular dosing, respectively. After intravenous administration, distribution was rapid (T_1/2(d) = 0.22 ± 0.09 h) and wide as reflected by the volume of distribution (V_(d(ss))) of 1.24 ± 0.08 L/kg. Plasma clearance was 0.28 ± 0.09 L/h·kg and elimination half‐life (T_1/2) 3.56 ± 0.62 h. Peak serum concentration (C_max), T_max, and bioavailability for the intramuscular administration were 7.97 ± 2.31 μg/mL, 0.12 ± 0.05 h, and 82.55 ± 23.64%, respectively. Thirty to 45 min after intravenous administration, lincomycin bone concentrations were 9.31 ± 1.75 μg/mL. At the same time after intramuscular administration, bone concentrations were 3.53 ± 0.28 μg/mL. The corresponding bone/serum ratios were 0.77 ± 0.04 (intravenous) and 0.69 ± 0.18 (intramuscular). Lincomycin MIC for Staphylococcus spp. ranged from 0.25 to 16 μg/mL and for Streptococcus spp. from 0.25 to 8 μg/mL.     

Comparison of Plasma Fentanyl Concentrations by Using Three Transdermal Fentanyl Patch Sizes in Dogs

Objective—To compare plasma fentanyl concentrations attained after the application of three transdermal fentanyl patch sizes (50, 75, and 100 μg/hour) in dogs. Design—Repeated Latin square controlled study. Animals—Six intact, mixed-breed adult dogs (2 males, 4 females) weighing 19.9 ± 3.4 kg. Methods—Each dog was randomly assigned to receive each of three treatments: 50 (P50), 75 (P75), or 100 (P100) μg/hour transdermal patches. Patches were left in place for 72 hours. Jugular venous blood was collected at 1,2, 4, 8, 12, 24, 36, 48, 60, and 72 hours after patch application and for 1, 2, 4, 8, and 12 hours after patch removal. Plasma fentanyl concentrations were measured using a radioimmunoassay technique. After a 96-hour washout period, each dog was moved to another treatment group and received a different patch size. Results—The following results were obtained (mean ± SD): average plasma fentanyl concentration from 24 to 72 hours, 0.7 ± 0.2 ng/mL (P50), 1.4 ± 0.5 ng/mL (P75), 1.2 ± 0.5 ng/mL (P100); the total area under the concentration versus time curve (0 hours to infinity), 46 ± 12.2 ng/h/mL (P50), 101.2 ± 41.4 ng/h/mL (P75), 80.4 ± 38.3 ng/h/mL (P100); and the apparent elimination half-life, 3.6 ± 1.2 hours (P50), 3.4 ± 2.7 hours (P75), and 2.5 ± 2.0 hours (P100). There was a high degree of variability in plasma fentanyl concentrations achieved. Plasma fentanyl concentrations declined rapidly after patch removal. Conclusions—The attainment of steady-state plasma concentrations takes up to 24 hours, and there is a great deal of variability in the final concentrations reached in different individuals. In this study, the 100 μg/hour patches did not provide statistically increased plasma concentrations when compared with the 50 μg/hour patches. Clinical Relevance—Because of the interindividual and intraindividual variation in plasma fentanyl concentrations, patches should be applied 24 hours before the anticipated time that analgesia will be required. Adequacy of analgesia and potentially deleterious side effects, such as sedation and respiratory depression, should be monitored while the patches are in place. Skin reactions may occur, and the patches should be removed if such skin irritation is seen. After the patch is removed, it is expected that analgesia will wane rapidly because of the brief elimination half-life.     

大气CO2浓度升高对绿色型豌豆蚜生长发育和繁殖的影响

为了研究大气CO₂浓度升高对绿色型豌豆蚜生长发育和繁殖的影响,应用CO₂人工气候箱,CO₂浓度设置中等浓度[(550±27) μL/L]和高浓度[(750±37) μL/L],并以当前浓度[(375±18) μL/L]为对照,观察并记录了饲养在蚕豆上的连续3代绿色型豌豆蚜的生长发育和繁殖指标。结果表明,随着CO₂浓度升高,连续3代绿色型豌豆蚜发育历期均缩短,初产若蚜体重、成蚜体重、体质量差和相对日均体重增长率均呈增加趋势;各世代的繁殖期延长,平均产蚜量和最大产蚜量均增加;各世代的净增殖率(R₀)增大,平均世代周期(T)延长,内禀增长率(r_m)和周限增长率(λ)均减小。因此,绿色型豌豆蚜的种群数量随着CO₂浓度升高而下降,故推测未来大气CO₂浓度的升高可能不利于豌豆蚜的发生。     

绿洲灌溉区与旱作区多龄苜蓿地土壤有机碳、氮及物理特性分析

以甘肃灌区和旱作区苜蓿(Medicago sativa)地土壤为研究对象,对不同地域的苜蓿地土壤全氮(TSN)、有机碳(SOC)、容重、含水量进行测定,结果表明:灌区SOC含量均高于旱作区,在90~100cm土层其含量与旱作区差值最大,达3.41g/kg。在0~100cm灌区SOC含量为6.81~12.49g/kg,均值为9.25g/kg,比旱作区高22%。旱作区TSN含量随土壤深度的增加而减小,含量在(1.03±0.01)~(0.44±0.04)g/kg。在0~30cm灌区TSN含量相对较稳定,差异不显著(P0.05),在30~60cm剖面全氮含量急剧下降,70~100cm含量变化较为稳定,TSN含量维持在(0.66±0.01)g/kg。旱作苜蓿地土壤含水量在0~60cm变化不显著(P0.05),0~100cm土壤含水量均值为(14.437±1.124)%,灌区苜蓿地土壤含水量均值为(16.025±2.029)%。随着土壤深度的增加,旱作区和灌区苜蓿地土壤容重均呈现依次增大的分布规律,旱作区最大值为(1.421±0.034)g/cm,比最小值高出17.5%,灌区最大值(1.332±0.017)g/cm,比最小值高出11.3%.     

The effects of L‐659,066, a peripheral α2‐adrenoceptor antagonist,and verapamil on the cardiovascular influences of dexmedetomidine in conscious sheep

Raekallio M. R., Honkavaara J. M., Vainio O. M. The effects of L‐659,066, a peripheral α₂‐adrenoceptor antagonist, and verapamil on the cardiovascular influences of dexmedetomidine in conscious sheep. J. vet. Pharmacol. Therap. 33 , 434–438. We investigated whether administration of L‐659,066, a peripheral α₂‐adrenoceptor antagonist, or verapamil, a calcium‐channel antagonist, would prevent the cardiovascular effects of dexmedetomidine. Eleven sheep received three intravenous treatments with a randomized, cross‐over design: dexmedetomidine (5 μg/kg, DEX); DEX with L‐659,066 (250 μg/kg, DEX + L); and verapamil (0.05 mg/kg) 10 min prior to DEX (Ver + DEX). Haemodynamics were recorded at intervals upto 40 min. Acute increases in mean arterial pressure (MAP) (106 ± 10.7 to 120.8 ± 11.7 mmHg), central venous pressure (CVP) (3.3 ± 3.2 to 14.7 ± 5.0 mmHg) and systemic vascular resistance (SVR) (1579 ± 338 to 2301 ± 523 dyne s/cm⁵), and decreases in cardiac output (CO) (5.36 ± 0.87 to 3.93 ± 1.30 L/min) and heart rate (HR) (88.6 ± 15.3 to 49.7 ± 5.5/min) were detected with DEX. The peak SVR remained lower after Ver + DEX (1835 ± 226 dyne s/cm⁵) than DEX alone, but the other parameters did not significantly differ between these treatments. 2 min after drug delivery, differences between DEX and DEX + L were statistically significant for all measured haemodynamic parameters. With DEX + L, an early decrease in MAP (99.9 ± 6.8 to 89.3 ± 6.6 mmHg) was detected, and DEX + L induced a slight but significant increase in CVP and a decrease in HR at the end of the observation period, while SVR and CO did not significantly change. All animals were assessed as deeply sedated from 2–20 min with no differences between treatments. L‐659,066 has great potential for clinical use to prevent the cardiovascular effects of dexmedetomidine mediated by peripheral α₂‐adrenoceptors, whereas the effects of verapamil were marginal.     

In Vitro Maturation of Dromedary (Camelus dromedarius) Oocytes: Effect of Different Protein Supplementations and Epidermal Growth Factor*

The present experiment was aimed to compare the effect of different protein supplementation sources, foetal calf serum (FCS), oestrous dromedary serum (EDS) and BSA, in experiment 1, and the effect of different concentrations of epidermal growth factor (EGF), in experiment 2, on in vitro nuclear maturation of the dromedary oocytes. Cumulus oocyte complexes (COCs) were harvested from the ovaries collected from a local slaughterhouse by aspirating the visible follicles in PBS supplemented with 5% FCS. Pooled COCs were randomly distributed to 4‐well culture plates containing 500 μl of the maturation medium and cultured at 38.5°C in an atmosphere of 5% CO₂ in air for 32–36 h. The basic maturation medium consisted of TCM‐199 supplemented with 0.1 mg/ml L‐glutamine, 0.8 mg/ml sodium bicarbonate, 0.25 mg/ml pyruvate, 50 μg/ml gentamicin, 10 μg/ml bFSH, 10 μg/ml bLH and 1 μg/ml estradiol. In experiment 1, this medium was supplemented with 10% FCS, 10% EDS or 0.4% BSA, whereas in experiment 2, it was supplemented with 0.4% BSA and 0, 10, 20 or 50 ng/ml of EGF. The oocytes were fixed, stained with 1% aceto‐orcein stain and their nuclear status was evaluated. Oocytes were classified as germinal vesicle, diakinesis, metaphase‐I, anaphase‐I (A‐I), metaphase‐II (M‐II) and those with degenerated, fragmented, scattered, activated or without visible chromatin as others. There was no difference (p > 0.05) observed in the proportion of oocytes reaching M‐II stage between the media supplemented with FCS (71.5 ± 4.8), EDS (72.8 ± 2.9) and BSA (72.7 ± 6.2). In experiment 2, a higher proportion (p < 0.05) of oocytes reached M‐II stage when the medium was supplemented with 20 ng/ml of EGF (81.4 ± 3.2) when compared with the media supplemented with 10 ng/ml (66.9 ± 4.1) and control (67.2 ± 7.1) groups. It may be concluded that the maturation media for dromedary camel oocytes can be supplemented with any of the three protein sources, i.e. FCS, EDS and BSA without any significant differences on the maturation rates. Also, a supplementation of 20 ng/ml of EGF in the maturation medium seems to be optimal and improves the nuclear maturation of dromedary camel oocytes.     

Pharmacokinetics of gamithromycin in cattle with comparison of plasma and lung tissue concentrations and plasma antibacterial activity

Huang, R. A., Letendre, L. T., Banav, N., Fischer, J., Somerville, B. Pharmacokinetics of gamithromycin in cattle with comparison of plasma and lung tissue concentrations and plasma antibacterial activity. J. vet. Pharmacol. Therap. 33 , 227–237. The pharmacokinetics (PK) and dose proportionality of gamithromycin (ZACTRAN^®), a novel azalide, after a single intravenous (i.v.) dose of 3 mg/kg or subcutaneous (s.c.) injection at 3, 6 and 9 mg/kg body weight were studied in 13 male castrate and 13 female Angus cattle. Following i.v. administration, the mean area under the curve extrapolated to infinity (AUC_inf) was 4.28 ± 0.536 μg·h/mL, and mean elimination half‐life (t_1/2) was 44.9 ± 4.67 h, with a large volume of distribution (V_ss) of 24.9 ± 2.99 L/kg and a high clearance rate (Cl_obs) of 712 ± 95.7 mL/h/kg. For cattle treated with s.c. injection of 3, 6 or 9 mg/kg, mean AUC_inf values were 4.55 ± 0.690, 9.42 ± 1.11 and 12.2 ± 1.13 μg·h/mL, respectively, and the mean elimination half‐lives (t_1/2) were 51.2 ± 6.10, 50.8 ± 3.80 and 58.5 ± 5.50 h. Gamithromycin was well absorbed and fully bioavailable (97.6–112%) after s.c. administration. No statistically significant (α = 0.05) gender differences in the AUC_Inf or elimination half‐life values were observed. Dose proportionality was established based on AUC_Inf over the range of 0.5 to 1.5 times of the recommended dosage of 6 mg/kg of body weight. Further investigations were conducted to assess plasma PK, lung/plasma concentration ratios and plasma antibacterial activity using 36 cattle. The average maximum gamithromycin concentration measured in whole lung homogenate was 18 500 ng/g at first sampling time of 1 day (～24 h) after treatment. The ratios of lung to plasma concentration were 265, 410, 329 and 247 at 1, 5, 10 and 15 days postdose. The lung AUC_inf was 194 times higher than the corresponding plasma AUC_inf. The apparent elimination half‐life for gamithromycin in lung was 90.4 h (～4 days). Antibacterial activity was observed with plasma collected at 6 h postdose with a corresponding average gamithromycin plasma concentration of 261 ng/mL. In vitro plasma protein binding in bovine plasma was determined to be 26.0 ± 0.60% bound over a range of 0.1–3.0 μg/mL of gamithromycin. The dose proportionality of AUC, high bioavailability, rapid and extensive distribution to lung tissue and low level of plasma protein binding are beneficial PK parameters for an antimicrobial drug used for the treatment and prevention of bovine respiratory disease.