Effect of cholecystokinin and secretin on contractile activity of isolated gastric muscle strips in guinea pigs

AIM To study the effect of cholecystokininoctapeptide (CCK-8) and secretin on contractile activity of isolated gastric muscle strips in guinea pigs.METHODS Each isolated gastric muscle strip was suspended in a tissue chamber containing5 mL Krebs solution constantly warmed by water jacked at 37℃ and supplied with a mixed gas of 95% O2 and 5% CO2. After incubating for 1 h under 1 g tension, varied concentrations of CCK-8 and secretin were added respectively in the tissue chamber and the contractile response was measured isometrically on ink-writing recorders.circular and longitudinal muscular tension at rest (fundus LM 19.7%±2.1%, P＜0.01; fundus CM 16.7% ±2.2%, P＜0.01; gastric body LM 16.8% ± 2.3%, P＜0.01; body CM 12.7% ± 2.6%,P＜0.01; antrum LM 12.3%±1.3%, P＜0.01;antrum CM 16.7%±4.5%, P＜0.01; pylous CM frequencies of body LM, both LM and CM of antrum and pylorus CM (5.1/min ± 0.2/min to 5.6/min ± 0.2/min, 5.9/min ± 0.2/min to 6.6/ min ±0.1/min, 5.4/ min ± 0.3/ min to 6.3/min ± 0.4/min, 1.3/ min ± 0.2/min to 2.3/min ± 0.3/ min,amplitude of antral circular muscle (58.6%±pylorus CM (145.0% ± 23.8%, P＜0.01), but decrease the mean contractile amplitude of gastric body and antral LM ( - 10.3% ± 3.3%, -10.5% ±4.6%, respectively, P＜0.05). All the CCK-8 effects were not blocked by atropine or indomethacin. Secretin had no effect on gastric smooth muscle activity.CONCLUSION CCK-8 possessed both excitatory and inhibitory action on contractile activity of different regions of stomach in guinea pigs. Its action was not mediated via cholinergic M receptor and endogenous prostaglandin receptor.     

高频听力损失对豚鼠低频区时间分辨率的影响

目的 构建豚鼠高频听力损失模型,通过听觉惊跳反射前抑制方法观察高频听力损失后,低频区时间分辨率的变化.方法 采用简单随机法将豚鼠分为实验组(6只)和对照组(4只),实验组暴露于声压级110 dB的12 kHz纯音下30 h,建立8 kHz以上听力损失模型,对照组未作处理.于噪声暴露前、暴露后2周、4周、6周及8周等五个时间点进行听觉惊跳反射前抑制试验和听觉脑干反应(ABR)测试.在听觉惊跳反射前抑制试验中,选用0.5～2 kHz,0.5～4 kHz和0.5～8 kHz三种背景噪音频率(均在听敏度正常的低频段)来观察低频区时间分辨率的变化.结果 噪声暴露后2周,实验组动物呈现8 kHz以上频率陡降型高频听力损失,在16 kHz、32 kHz和48 kHz频率均有平均55 dB的阈移,与声暴露前相比差异均有统计学意义(P值均＜0.05),而1 kHz、2 kHz、4 kHz和8 kHz在噪音暴露前后差异均无统计学意义(P值均＞0.05).在8周的实验期内,实验组高频听力损失仍然存在.对照组豚鼠所有频率的听敏度在实验期内各个时间点差异均无统计学意义(P值均＞0.05).实验组在8 kHz的背景噪音下,声暴露后第2周抑制能力减弱,与暴露前相比差异具有统计学意义(P=0.036),其余时间点和暴露前相比差异无统计学意义(P值均＞0.05);在4 kHz的背景噪音下,声暴露后所有时间点的抑制能力与暴露前相比差异均无统计学意义(P值均＞0.05);在2 kHz的背景噪音下,声暴露后第6周、第8周抑制能力降低,与暴露前相比差异具有统计学意义(P值均＜0.05).结论 高频听力损失可降低正常低频区的时间分辨率.

Abstract：

Objective To constitute the animal model of high frequency hearing loss and observer the temporal processing abilities of low frequency regions using prepulse inhibition of auditory startle response (gap-PPI).Methods Ten guinea pigs were randomly grouped into two groups: the high frequency hearing loss group with six guinea pigs and the control group with four guinea pigs.The former group was exposed to 12 kHz tone at 110 dB SPL for 30 hours to establish the high frequency hearing loss above 8 kHz and the latter group received no stimuations.Before and two,four,six and eight weeks after noise exposure,gapPPI and auditory brainstem response (ABR) were recorded in both groups.In the gap-PPI experiment,three different background noises as 0.5-2 kHz,0.5-4 kHz and 0.5-8 kHz were applied to test the temporal gap.Results High frequency hearing loss above 8 kHz was shown two weeks after noise exposure.The averaged ABR thresholds of 16 kHz,32 kHz and 48 kHz were elevated about 55 dB and shown statistical significance compared to those before exposure (P ＜ 0.05＝.No significant difference of ABR thresholds were shown between 1 kHz,2 kHz,4 kHz and 8kHz before and after noise exposure(P ＞0.05).In the control group,the ABR thresholds remained stable during experiment.In the gap-PPI test,two weeks after noise exposure of 8 kHz,the experiment group showed attenuated inhibition ability and recovered gradually four weeks after noise exposure.No statistical differences of inhibition ability at time points of two,four,six and eight weeks after noise exposure of 4 kHz were detected when compared with that of pre-exposure.Under the background noise of 2 kHz,the inhibition ability attenuated and reached statistical significance at 6-8 weeks after noise exposure.Conclusion The high frequency hearing loss might induce an impairment of the temporal processing in the low frequency region.     

江西省表观健康猪群携带猪链球菌状况分析

目的：了解江西省表观健康猪群携带猪链球菌的情况,为有效防控猪链球菌病提供科学依据。方法选取景德镇市、崇仁县为采样点,采集表观健康猪群鼻咽拭子和扁桃体进行猪链球菌病原分离鉴定。结果共采集表观健康猪群鼻咽拭子和扁桃体样本301份,检出2株猪链球菌2型,其毒力基因mrp、sly、ef均为阴性。结论本次调查中江西省表观健康猪携带猪链球菌的带菌率为0.66％。     

融水小型猪剖检程序以及主要脏器自发性病变组织学观察

目的掌握融水小型猪主要器官解剖学及组织学数据。方法选择6月龄F1代小型猪雌雄各两头,麻醉后测体重,进行大体解剖,颈动脉取血测定全身血量、血浆量,记录脊柱数量和恒齿齿式,取出主要脏器进行拍照、称重及测量,切取脏器的部分组织,用福尔马林固定后做组织切片,在显微镜下观察并拍照。结果获得了融水小型猪的主要脏器形态图片、组织学显微图片、主要脏器重量、脏器系数及其他基础数据。结论初步掌握了融水小型猪的器官解剖学和组织学基础数据。     

经球囊导管肝段热凝固CT与病理对照研究

目的观察经球囊导管阻断肝动脉高热灌注生理盐水行肝段热凝固CT表现。方法实验猪6头,选用球囊导管阻断肝段动脉血流进行热灌注,导管流出温度设置50~60℃之间。热灌注结束后即刻、14天,行肝动脉DSA检查和肝脏螺旋CT扫描,14天将实验猪全部处死,取出肝脏进行病理检查。结果热灌注后14天,6头实验猪均存活。DSA检查见靶段动脉闭塞,肝组织热灌注区显示充盈缺损。肝脏热灌注区CT影像学表现:热灌注结束后即刻,热灌注区显示大片状低密度改变,无明显强化,边缘显示模糊;热灌注后14天,CT平扫示肝脏热灌注区呈典型楔形低密度改变;CT增强示热灌注区显示"三环征",由内向外分为低密度无增强区、边缘强化带和移行区透明带。病理上取得6个热凝固灶,CT上低密度无增强区、边缘强化带和移行区透明带分别代表病理的凝固性坏死区、炎性充血带和纤维化带。结论增强CT能准确反映经动脉导管肝段介入性热毁损的病理改变,DSA价值有限。     

豚鼠主动全身过敏试验两种阳性物质选择的探讨

目的 比较两种阳性物质人血白蛋白、卵白蛋白对豚鼠主动全身过敏作用,为过敏性试验提供较好的阳性对照。方法 将豚鼠随机分为14组,以人血白蛋白、卵白蛋白(2、10、100 mg/只)、0.9%氯化钠注射液等受试物为对照,研究不同致敏剂量、激发剂量、激发时间等条件下,豚鼠全身主动过敏的反应情况。结果 在2~100 mg/只剂量范围内,人血白蛋白、卵白蛋白豚鼠主动全身过敏反应的发生率为100%。在2~10 mg/只剂量范围内,过敏症状发生程度随致敏剂量、激发剂量的增加而增加,相同剂量的卵白蛋白较人血白蛋白反应程度更强。结论 豚鼠主动全身过敏试验,阳性对照推荐使用卵白蛋白,剂量为2 mg/只。     

融水小型猪的实验动物化系列研究概述

融水小型猪的种源来自广西融水县,2012年被引到广东繁育并测定了基础数据,包括种质特性、繁殖性能、生长曲线、血液学指标、血生化指标、脏器系数、染色体分析。参照国家和地方有关实验动物标准,初步建立了融水小型猪微生物与寄生虫、环境与设施、饲料、病理学、遗传学等质量控制标准。融水小型猪能适应当地气候,繁殖良好,自然受孕率为88.3%,妊娠期平均112 d,初产平均胎产仔6.1头,经产平均产仔7.9头。融水小型猪体型小,雌雄成年体重(6月龄)分别为17.21±5.20 kg和16.35±5.23 kg,性情温顺,线粒体DNA分析表明融水小型猪比兰屿猪更为古老。通过标准化的饲养管理与质量控制,具有培育成实验用小型猪的基本条件。     

Application of sodium alginate microspheres in ischemic stroke modeling in miniature pigs

The miniature pig is an optimal animal model for studying nervous system disease because of its physiologic and pathologic features. However, the rete mirabile composed of arteries and veins at the skull base limits their application as a model of ischemic stroke by middle cerebral artery occlusion. The present study investigated the possibility of establishing an ischemic stroke model in the miniature pig by blocking the skull base retia with sodium alginate microspheres. Three Bama miniature pigs were used. Using the monitor of C-arm X-ray machine, sodium alginate microspheres (100-300 μm), a novel embolic material, were injected through the femoral artery, aortic arch, common carotid artery, ascending pharyngeal artery and the retia. Results were evaluated using carotid arteriography, MRI, behavior observation and histology. The unilateral rete mirabile was completely blocked, resulting in disturbance in blood supply to the basal ganglia, astasia of the right hind limb and salivation. MRI and hematoxylin-eosin staining showed an evident infarction focus in the basal ganglia. These findings indicate that sodium alginate microspheres are a suitable embolic material for blocking the skull base retia in miniature pigs to establish an ischemic stroke models.     

冠状动脉内多普勒超声评价猪急性冠状动脉闭塞侧支循环状态及影响因素

目的评价猪急性闭塞冠状动脉侧支循环状态及硝酸甘油和酚妥拉明对其的影响。方法使用冠状动脉内多普勒超声测定14头小型家猪正常状态及急性闭塞后左回旋支的血流频谱,并观察冠状动脉内应用硝酸甘油和酚妥拉明对其的影响。结果急性闭塞10min时回旋支远端的平均峰值流速(APV)明显低于正常(0.97±1.05cm/s比25.78±4.36cm/s,P<0.01),应用硝酸甘油和酚妥拉明后梗死相关血管变为反向或双向血流,APV绝对值(8.32±1.53cm/s和8.54±2.15cm/s)较用药前明显增加(P<0.01);闭塞后90min时及重复应用上述两药后APV分别为0.99±1.14cm/s、9.02±1.47cm/s和8.95±2.36cm/s,闭塞90min较闭塞即刻差异无统计学意义,用两药后APV值差异无统计学意义(P均>0.05)。结论猪急性冠状动脉闭塞时侧支循环自身建立不足,硝酸甘油和酚妥拉明均可明显增加冠状动脉侧支循环血流。