灵敏专属的HPLC法测定比格犬中非索非那定的浓度

目的建立简便的测定血浆中非索非那定血药浓度的高效液相色谱法.方法流动相为乙腈∶0.02磷酸缓冲液(35∶65,V∶V),流速为1.0 mL·min-1.柱温40 ± 1 ℃,检测波长210 nm.结果标准曲线的线性范围在10～1000 ng·mL-1,r = 0.999 4.最低检测限为3 ng·mL-1.高(800 ng·mL-1)、中(400 ng·mL-1)、低(10 ng·mL-1) 浓度提取回收率分别为85.2%±4.2%, 88.0%±3.9%和89.7%±3.5%;日间和日内RSD分别低于6.1%和4.2%.结论所建立的方法灵敏、快速、重现性好、选择性强.     

Kinetics of hypodermically injected technetium-99m and correlation with cutaneous structures: an experimental study in dogs

We investigated the involvement of cutaneous structures in specific linear migration pathways of technetium-99m pertechnetate hypodermically injected at points of low electrical resistance in the metacarpus of male beagles. Skin-deep incisions were made in the front or back legs on either the same side as the ^99mTc injection or on the opposite side. Incisions in the back legs did not affect the migration pattern. Incisions in the front legs before the injection of ^99mTc prevented tracer migration. After the injection of ^99mTc, incisions in the front contralateral leg caused sudden cessation of the migration, while incisions in the ipsilateral leg caused immediate disappearance of the pathway previously observed. Radioactivity was not detected in flaps obtained from the skin overlying the migration pathway or from the corresponding area of the contralateral leg. In conclusion, the specific linear migration pathways of ^99mTc hypodermically injected at points of low electrical resistance cannot be explained by any known biological function. Although the migration of ^99mTc does not seem to be strongly linked to any cutaneous structure, the skin overlying the radioactive pathway and the corresponding area of the contralateral leg must be intact if tracer migration is to take place.     

Low dose of human PTH(1-34) improved tibial subcortical bone mass without further cortical bone loss in adult intact beagles

Cortical bone loss has not been observed in parathyroid hormone- (PTH-) treated rats, but clinical investigators suggest that it may augment cancellous bone mass at the expense of cortical bone in PTH-treated patients. In this study, the effects of PTH on cancellous and cortical bone mineral density of the tibia were studied in dogs with Haversian cortical bone remodeling by peripheral quantitative computed tomography (pQCT). Sixteen 19- to 20-month-old beagle dogs were randomized into four groups. In group 1, the vehicle control group, saline was injected daily throughout the experimental period. In group 2, the sequential group, 0.375 μg/kg of hPTH(1-34) was injected daily during the first 4 weeks, then stopped for 8 weeks, and this sequence was once repeated (on 4 weeks, off 8 weeks, and on 4 weeks, off 8 weeks). In group 3, the one-time group, the same dose of PTH was injected once per week for 24 weeks. In group 4, the three-time group, the same dose of PTH was given three times per week for 24 weeks. Peripheral QCT measurements were carried out 7 mm distal to the growth plate in the proximal metaphysis of the tibia. A voxel size of 0.295 mm and threshold for cortical and subcortical bone of 0.930 was chosen throughout the experiment. In adult beagles, group 4 had a significantly higher value in subcortical bone mineral density (SubCt.BMD) than control group (852 vs 771 mg/mm³; P < .05). Higher but non-significant increase occurred in the PTH-treated animals (groups 2, 3, 4) in the following parameters: total (Total.BMD), cancellous bone mineral density (Cn.BMD), cortical bone mineral density (Ct.BMD), and cortical thickness (Ct.Th). These findings show that a low dose of PTH improved subcortical bone mineral density without decreasing cortical bone mineral density during this dosage and period. Received: Sept. 8, 1997 / Accepted: Jan. 6, 1998     

胶囊内镜用于比格犬上消化道检查方法的建立与初步应用

目的 探索胶囊内镜用于比格犬等较大体型动物上消化道黏膜疾病实时监测的方法及可行性.方法 (1)对PillCam SB2型胶囊内镜进行简单改造,采用4号手术线一端束缚胶囊内镜的腰部做牵引线,另一端从胃管的顶端穿过,从一侧孔穿出胃管,通过拉伸将胶囊内镜顶靠在胃管的前端;(2)麻醉比格犬,胃管辅助胶囊内镜通过比格犬口咽送入食管、胃腔.(3)40％无水乙酸40 ml灌胃,胶囊内镜检查系统观察消化道黏膜变化.结果 (1)改装后的胶囊内镜在胃管的帮助下可以顺利地进入比格犬食管和胃内,并可通过拉伸牵引线将胶囊式内镜顶靠在胃管的前端部,控制胶囊内镜改变拍摄位置和角度.(2)40％无水乙酸40 ml灌胃,成功制造比格犬急性胃黏膜病变模型.(3)胶囊内镜可以清晰拍摄胃腔图像,观察胃黏膜在不同时间点出现的不同表观变化,实现对动物消化道疾病模型黏膜变化的实时监测.结论 成功建立了胶囊内镜实时监测上消化道黏膜急性病变发生发展的方法,将其初步应用于观察体型较大动物比格犬胃黏膜急性损伤过程中的表观变化是可行的.     

Effect of age, castration, and testosterone replacement on the development and restoration of canine benign prostatic hyperplasia

An experiment was designed to test the effect of castration and testosterone replacement on the development of benign prostatic hyperplasia (BPH) in young and on the restoration of BPH in old beagles. Twenty beagles were divided by age into young (1.5-2.5-yr) and old (6.0-8.5-yr) groups. Each of these groups was further divided randomly into two additional groups of age-matched, intact, untreated control and castrate beagles. The latter were then treated with testosterone-filled Silastic implants designed to clamp serum testosterone at concentrations similar to those observed in adult beagles for 7 months beginning 5 months after castration. Histopathologic characterization of each prostate was completed on biopsy material obtained at the beginning and end of the experiment. Prostate weights were determined each month for 12 months via a noninvasive two-dimensional X-ray procedure. Testosterone treatment for 7 months allowed BPH to develop in young and restored BPH in old beagles. These results suggest that testosterone in the adult beagle acts permissively to allow BPH to develop in the prostate of the aging dog. Some other testicular product may be required for the continued growth of BPH in aged beagles.     

Capillary Gas Chromatographic (GC) Analysis of Nitroglycerin and Its Denitration Products in Plasma

A convenient, specific, and sensitive capillary gas chromatographic (GC) assay for analyzing nanogram concentrations of nitroglycerin and its dinitro- and mononitrometabolites in plasma has been developed. Using a bonded-phase (DB-1) 30-m, 1-µm-thick film capillary column and a 1-m, 5-µm-thick film precolumn, separation of nitroglycerin and all four partially nitrated metabolites was achieved in less than 15 min. On-column injection, electron capture detection, and isothermal operation at 100°C yielded a linear extraction curve over a 300-ng/ml range without any need to concentrate sample extracts. Using methyl t-butyl ether as extraction solvent and o-chloronitrobenzene as internal standard, recoveries from plasma spiked at levels greater than 10 ng/ml approximated 35% for the 1-monometabolite, 40% for the 2-monometabolite, and greater than 90% for all others. The method was employed in a pharmacokinetic study of nitroglycerin administered intravenously to beagle dogs. Plasma samples were collected at various time points and analyzed.     

超声引导下急性缺血性左室舒张功能障碍并二尖瓣反流犬模型的构建

 目的 探讨超声引导下急性缺血性左室舒张功能障碍并二尖瓣反流犬模型的构建。方法 (1)二尖瓣反流模型的建立:比格犬15条,经左颈动脉穿刺并送入动脉鞘。在超声引导下,将动脉鞘送入左室,鞘前端置于二尖瓣前叶边缘,经动脉鞘将内镜活体取样钳置于二尖瓣尖下,钳断二尖瓣腱索。经胸心脏超声证实存在二尖瓣反流。(2)急性缺血性左室舒张功能障碍模型的建立:在超声引导下,外撤动脉鞘使其前端置于左冠状动脉窦内,间歇多次注射塑料微球于左冠状动脉窦内,微栓塞冠状动脉,左室舒张末压升高≥5 mmHg定义为建模成功,形成急性缺血性舒张功能不全。结果 (1)15条比格犬制作二尖瓣反流模型全部成功;14条犬形成中度二尖瓣反流,1条比格犬造成重度二尖瓣反流。多普勒频谱测量二尖瓣反流,V max为(483.0 ±1.1) m/s,PG max为(162.7± 1.8) mmHg。(2)15条二尖瓣反流比格犬进行急性缺血左室舒张功能障碍模型构建,成功12条,3条未成功。12条成功模型的左室舒张末压升高、最大左室压力下降速率(-dP/dtmax)降低、左室松弛时间常数(Tau)延长。结论 超声引导下,经颈动脉鞘管送入活检钳钳夹二尖瓣腱索制造二尖瓣反流(MR)、间歇多次注射微球入左冠状动脉窦构建急性缺血性舒张功能障碍比格犬模型,具有操作简便、方法可靠、成功率高等优点。     

HYPOTENSIVE RESPONSE TO ATRIAL NATRIURETIC FACTOR IN CONSCIOUS RENAL HYPERTENSIVE BEAGLES

The hemodynamic responses to i.v. infusion of 0.3 and 0.6 microgram/kg per min of human atrial natriuretic factor (hANF [102-126]) in intact, conscious, one-kidney, perinephritic, hypertensive beagles were examined and compared with the responses in ganglionic-blocked dogs. Blood pressure and heart rate were not affected but plasma ANF-like immunoreactivity was increased by as much as 627%. After hexamethonium (20 mg/kg, i.v.) blockade, a dose-dependent hypotensive response of up to 29 mmHg with no change in heart rate was observed. It is concluded that the compensatory mechanisms of the neurally mediated baroreflex system masked the depressor actions of hANF.     

Evaluation of gastrointestinal pH and gastric residence time via the Heidelberg radiotelemetry capsule: Pharmaceutical application

The Heidelberg Radiotelemetry Capsule (7 mm diameter x 20 mm length) represents a noninvasive device to monitor gastrointestinal (GI) pH and to evaluate gastric residence time (GRT) in both animals and humans. Due to its large size and indigestible nature, gastric emptying of the Heidelberg capsule occurs during the 5–15 min of Phase III migrating motor complex (MMC), which is responsible for emptying of indigestible debris leftover from a meal, the so-called housekeeper wave of the GI tract. Following initial in vitro accuracy and in vivo reproducibility studies, the Heidelberg capsule was used in young beagle dogs and normal healthy subjects. In the fasting state, gastric pH was comparable in dogs and humans (1.5 ± 0.04 vs. 1.1 ± 0.15, mean ± SEM), where postprandially a more acidic pH was reported in beagle dogs (2.1 ± 0.04 vs. 3.6 ± 0.4). Both duodenal and fasting intestinal pHs were consistently higher in dogs than humans. Although fasting GRT of the Heidelberg capsule was similar between the two species (1.2 ± 0.33 vs. 1.2 ± 0.45 h), high intersubject variability in the GRT estimation was observed in both dogs and humans. The Heidelberg radiotelemetry technique was utilized in several clinical studies to evaluate the influence of physical and physiological parameters which alter the normal GI motility (i.e., food with varying composition and energy density, posture, gender, age, and gastric alkalinization). The results of pH and GRT measurements via the Heidelberg capsule were found to be sensitive and responsive toward factors which alter the GI motility, and therefore, the Heidelberg capsule may be used in the clinical studies as a model for a large, nondisintegrating solid dosage form (i.e., enteric-coated formulations). Subsequently, the Heidelberg capsule was administered together with the enteric-coated aspirin (which is known for high inter- and intra-subject absorption variability) and with a more challenging enteric-coated formulation, diclofenac sodium. The results demonstrated that by reasonable estimation of the GRT, the Heidelberg capsule is capable of explaining and minimizing the traditional absorption variabilities observed with these formulations. In summary, the Heidelberg radiotelemetry device can be used as a noninvasive means of GI pH and transit time. This accurate and reproducible telemetry system mimics the GI transit of a large indigestible solid dosage form and may be used in both animal research and human oral bioavailability/bioequivalency studies. © 1996 Wiley-Liss, Inc.     

通脉颗粒在急性心肌缺血模型比格犬体内药动学研究

通脉颗粒(TM)是由丹参、川芎、葛根组方而成,临床上用于对缺血性心脑血管疾病的治疗。为研究TM的药效物质基础,对急性心肌缺血模型比格犬给予TM干预,分析了血清中吸收成分及其药动学特征。以盐酸酸化-乙酸乙酯萃取法提取血清样品,在LS-MS/MS的ESI-检测模式下,采用Merck RP-18e整体反相硅胶色谱柱分离,以乙腈-甲醇1∶1(0.07%FA)和水(0.01%FA)为流动相,在优化的梯度洗脱程序下实现了在8.5 min内对犬血清中8种葛根黄酮成分、5种丹参酚酸成分和2种葛根成分的同时定量分析。分析方法的验证结果表明该方法特异、准确、精密,符合生物分析要求。对急性心梗模型比格犬十二指肠注射TM后6 h内不同时间点血清样品的分析结果显示,给药后5 min药物成分即吸收入血,15种成分均能在血清中检出,分别于给药后0.18~3.83 h达峰。各成分的血药浓度差异很大,其中葛根素、丹参素体内暴露量远高于其他成分,其次为3'-甲氧基葛根素、芹糖基葛根素和3'-羟基葛根素。研究结果表明葛根异黄酮类和丹参素是TM在心肌缺血模型犬体内的主要活性成分。