豚鼠气道上皮对钾通道开放剂Rp52891作用的影响

为了观察气道上皮对钾通道开放剂Ｒｐ５２８９１作用的影响，将正常豚鼠和致敏豚鼠的气管螺旋条随机分成完整上皮组和去除上皮组，用组胺诱发收缩后，分别加入Ｒｐ５２８９１、氨茶碱及异丙肾上腺素，测定气管螺旋条对组胺及上述三种物质的反应。结果发现，正常豚鼠和致敏豚鼠气管螺旋条对组胺的反应性在两组间差异无显著性（Ｐ＞０．０５），Ｒｐ５２８９１对去除上皮组的舒张作用明显弱于完整上皮组（Ｐ＜０．０５），氨茶碱和异丙肾上腺素的舒张作用在两组间差异无显著性（Ｐ＞０．０５）。提示Ｒｐ５２８９１可直接舒张气道平滑肌，气道上皮参与介导其舒张作用。     

Tracheal responsiveness to both isoprenaline and beta2-adrenoreceptor blockade by propranolol in cigarette smoke exposed and sensitized guinea pigs

OBJECTIVE: Airway hyperresponsiveness is the main feature of asthma and also exists in cigarette smokers. In previous studies we have shown increased airway responsiveness to isoprenaline in asthmatic patients and smokers. In this study, tracheal responsiveness to isoprenaline and beta-adrenergic receptor blockade was investigated in animals exposed to cigarette smoke (AECS) with or without sensitization by ovalbumin (OA). METHODOLOGY: Guinea pigs were exposed to cigarette smoke over a 3-month period with or without sensitization by injection and inhalation of OA. Tracheal responses in AECS, AECS + sensitized and control animals (n = 7 for each group) to isoprenaline in the absence and presence of 20 nmol/L propranolol were measured and EC(50) was established. The propranolol blockade (concentration ratio minus one (CR-1)) was calculated (post-propranolol EC(50)/EC(50)) - 1. RESULTS: The tracheal response of AECS and AECS + sensitized guinea pigs to isoprenaline was significantly higher than that of control animals (EC(50): 4.24 +/- 0.54, 3.66 +/- 0.53 and 7.71 +/- 0.68.79 micromol for AECS, AECS + sensitized and control animals, respectively) (P < 0.001). There was no significant difference in EC(50) between AECS and AECS + sensitized. CR-1 was also significantly higher in the trachea of AECS and AECS + sensitized compared with controls (13.39 +/- 2.22 and 15.35 +/- 2.95 vs. 3.10 +/- 0.6, P < 0.05 in both cases). There was no significant difference in CR-1 between AECS and AECS + sensitized. There was a significant correlation between the tracheal response to isoprenaline (EC(50)) and CR-1 (r =-0.731, P < 0.001). There was no significant difference in tracheal maximum response to isoprenaline between the three groups of animals. CONCLUSIONS: The results of this study indicate an increased tracheal response to a beta(2)-adrenergic stimulating drug and enhanced beta(2)-adrenergic blockade by propranolol in both AECS and AECS + sensitized. These results suggest similar increase in airway responsiveness to beta(2)-adrenergic agonists and beta(2)-receptor blockade in AECS and AECS + sensitized guinea pigs.     

Comparative study on the stability of soybean (Glycine max) β-conglycinin in vivo

The immunoreactivity and structural variation of β-conglycinin in digesta from digestive tracts of pigs were measured by inhibition ELISA and sodium dodecyl sulphate polyacrylamide gel electrophoresis, respectively. Results showed that the immunoreactivity disappearance proportion of β-conglycinin significantly increased from stomach to the caecum in all groups (P<0.05). In the stomach, upper-jejunum and middle-jejunum, the immunoreactivity disappearance proportion of β-conglycinin significantly increased among these three groups (P<0.05), while it has no significant difference in ileum and caecum (P>0.05). The α′, α subunits of β-conglycinin were easier to digest than the β subunit. It indicated that immunoreactivity disappearance proportion of β-conglycinin tended to increase with the growth of age and the descending down of digestive tract, while the β subunits of β-conglycinin are more stable to digestion than α′, α subunits.     

高糖环境对豚鼠膀胱Cajal样间质细胞内向电流的影响

目的观察高糖环境对豚鼠膀胱Cajal样间质细胞（ICCs）内向电流的影响。方法采用胶原酶消化法,得到原代培养的成年豚鼠膀胱ICCs;采用膜片钳技术,在全细胞记录模式下,记录葡萄糖5（对照组）、15（高糖Ⅰ组）、30mmol／L（高糖Ⅱ组）下ICCs超极化激活时的内向电流值。结果正常对照组膀胱ICCs的内向电流值为（505．75±157．660）pA,高糖Ⅰ组为（349．25±71．087）pA,高糖Ⅱ组为（95．00±33．337）pA。三组间比较,P均〈0．01。结论高糖环境可导致豚鼠膀胱ICCs超极化激活的内向电流值降低,这可能是导致糖尿病膀胱病变的原因之一。     

Long‐Term Controlled Normoglycemia in Diabetic Non‐Human Primates After Transplantation with hCD46 Transgenic Porcine Islets

Xenotransplantation of porcine islets into diabetic non‐human primates is characterized by (i) an initial massive graft loss possibly due to the instant blood‐mediated inflammatory reaction and (ii) the requirement of intensive, clinically unfriendly immunosuppressive therapy. We investigated whether the transgenic expression of a human complement‐regulatory protein (hCD46) on porcine islets would improve the outcome of islet xenotransplantation in streptozotocin‐induced diabetic Cynomolgus monkeys. Immunosuppression consisted of thymoglobulin, anti‐CD154 mAb for costimulation blockade, and mycophenolate mofetil. Following the transplantation of islets from wild‐type pigs (n = 2) or from 1,3‐galactosyltransferase gene‐knockout pigs (n = 2), islets survived for a maximum of only 46 days, as evidenced by return to hyperglycemia and the need for exogenous insulin therapy. The transplantation of islets from hCD46 pigs resulted in graft survival and insulin‐independent normoglycemia in four of five monkeys for the 3 months follow‐up of the experiment. One normalized recipient, selected at random, was followed for >12 months. Inhibition of complement activation by the expression of hCD46 on the pig islets did not substantially reduce the initial loss of islet mass, rather was effective in limiting antibody‐mediated rejection. This resulted in a reduced need for immunosuppression to preserve a sufficient islet mass to maintain normoglycemia long‐term.     

分阶段添加细胞诱导因子诱导豚鼠脂肪间充质干细胞定向分化内耳毛细胞

背景：感音神经性耳聋主要是由内耳毛细胞的缺失或受损造成,用脂肪间充质干细胞来再生修复内耳毛细胞是治疗听力损失的有效方法。目的：探讨体外定向诱导豚鼠脂肪间充质干细胞向内耳毛细胞样细胞分化的可行性。方法：体外分离培养豚鼠脂肪间充质干细胞至第3代,流式细胞仪检测细胞免疫表型,分阶段加入表皮生长因子、碱性成纤维细胞生长因子、胰岛素样生长因子1、全反式维甲酸、脑源性神经营养因子、神经营养因子3,观察诱导分化的效果。结果与结论：豚鼠脂肪间充质干细胞体外培养呈梭形,漩涡状贴壁生长,第3代细胞表面标记CD29与CD44表达呈现阳性,CD34与CD45表达呈现阴性。应用细胞因子诱导后细胞早期nestin和GFAP表达阳性,继续诱导10 d后表达毛细胞特异性标记物MyosinⅦa和Math1,说明细胞因子可定向诱导豚鼠脂肪间充质干细胞向内耳毛细胞分化。     

Non-invasive measurement of adrenocortical and gonadal activity in male and female guinea pigs (Cavia aperea f. porcellus)

Taking blood samples is a common method in biomedical and biological research using guinea pigs. However, most blood sampling techniques are complicated and highly invasive and may therefore not be appropriate for certain research topics concerning stress and reproduction. Thus, a non-invasive method to measure steroid hormones is critically needed. The aim of this study was the biological validation of corresponding enzyme immunoassays for the measurement of fecal cortisol, progesterone, estrogen, and testosterone metabolites in guinea pigs. We examined the effect of subcutaneous injections of ACTH or saline on fecal cortisol metabolites to investigate the suitability of fecal samples to monitor adrenocortical activity. Furthermore, we investigated whether fecal sex steroid metabolites accurately reflected endocrine changes observed in plasma samples during female estrous cycles and male puberty, respectively. In addition, we compared fecal testosterone metabolites of intact males, castrated males, and females to investigate the reliability of fecal samples in discriminating gonadal status of males. Concentrations of fecal cortisol metabolites were significantly increased following ACTH challenge, indicating that adrenocortical activity can be monitored via fecal samples. Secondly, in females, plasma and fecal gonadal steroids were significantly correlated in most subjects. The assay for testosterone metabolites, on the other hand, could not clearly discriminate between test groups. From these findings we conclude that fecal samples can be used for the non-invasive assessment of adrenocortical and female reproductive status in guinea pigs. Testosterone metabolism seems to be more complex and further investigations are needed to establish a more suitable assay.     

Effect of the calcium sensitizer levosimendan on the performance of ischaemic myocardium in anaesthetised pigs

The calcium sensitizer levosimendan (LEV) improves the function of stunned myocardium, cardiac performance in heart failure, and possibly the efficiency of myocardial work. The present experiments investigated the effect of LEV on myocardial contraction and metabolism of acutely ischaemic myocardium distal to a functionally effective coronary artery stenosis. Anaesthetised open chest pigs (n = 14) were instrumented to assess heart rate (HR), aortic pressure (AoP), cardiac output (CO), blood flow in the left descending (QLAD) and circumflex (QLCX) coronary artery, myocardial end-diastolic segment length and systolic shortening (edL, MSS by sonomicrometry) in the LAD- and LCX-territory. Systemic vascular resistance (SVR), and a myocardial power index (PowI) for the LAD- and LCX-region were calculated. Following obstruction of QLAD by an external snare proximal to the first diagonal branch LEV was given intravenously (10 + 20 + 30 g/kg 15 min apart, n = 8) or the vehicle of LEV (n = 6). Following LEV haemodynamics and regional myocardial performance changed significantly: HR +22 min^–1, AoP –6 mmHg, CO +17%, SVR –21%; intact myocardium: QLCX +15%, RLCX –24%, PowILCX + 39%; ischaemic myocardium: QLAD –7%, MSSLAD –42%, PowILAD –27%. The data confirm the pharmacological profile of LEV: positive chronotropy, positive inotropy, and vasodilatation. The pump function of acutely ischaemic myocardium worsened following LEV. The efficiency of myocardial performance did not improve. A beneficial effect of LEV on the function of ischaemic myocardium was possibly outmanoeuvred by the increase in heart rate.