pH and bicarbonate in the ductuli efferentes testis of the rat

The pH and bicarbonate concentrations of luminal fluids in the efferent ducts of the rat were estimated from pH measurements of samples in vitro under conditions of controlled temperature and carbon dioxide tension. The pH of scrotal blood was estimated to be more acidic than systemic blood (mean pH=7.44) at either of the putative scrotal carbon dioxide tensions (5% and 7%, pH, respectively,=7.42 and 7.28). For PCO2 tensions of 5% and 7%, respectively, the data indicated that the pH in the efferent ducts was significantly higher (distal initial zone pH=7.55 or 7.41; coni vasculosi pH=7.66 or 7.51; p < 0.01) than in fluid entering (rete testis fluid, pH=7.34 or 7.20) or leaving the ducts (zone 1a of the epididymal duct 7.26 or 7.11). Bicarbonate concentrations were also significantly higher (p < 0.01) in the efferent ducts (35.4 +/- 4.7 mM, distal initial zone; 45.2 +/- 7.6 mM, coni vasculosi) than in fluids entering (22.9 +/- 3.6 mM) or leaving (20.4 +/- 4.9 mM) the ducts. Estimates of the reabsorption of bicarbonate and fluid indicated that 96% of the testicular output of bicarbonate was reabsorbed in the efferent ducts, but there was also some secretion of bicarbonate into the ducts. It is concluded that luminal pH and bicarbonate levels in the efferent ducts of the rat are high relative to those found in the epididymis where low pH and bicarbonate contributes to sperm quiescence during storage. Nevertheless, the high rate of bicarbonate reabsorption in the efferent ducts is a major contributor to the establishment of the low pH and bicarbonate milieu of the epididymis.     

pH对盐酸美普他酚鼻腔吸收的影响

目的研究盐酸美普他酚制剂中pH和鼻腔吸收之间的关系.方法通过鼻腔在体循环试验考察不同pH环境对盐酸美普他酚鼻腔吸收的影响,并利用体内试验考察模型药物经鼻入脑的情况.结果鼻腔在体循环试验发现盐酸美普他酚在碱性条件下吸收显著优于酸性条件,但是在体内试验中发现不同pH环境对药物吸收入脑并没有显著性差异.结论制剂中的pH环境对盐酸美普他酚鼻腔吸收和入脑无显著影响.     

利用粘附式细胞仪测定培养巨噬细胞内pH值

用ｐＨ值敏感荧光探针Ｓｎａｆｌｃａｌｃｅｉｎ－ＡＭ标记体外培养４８小时的小鼠腹腔巨噬细胞，５７０型粘附式细胞仪观察巨噬细胞在对刀豆素Ａ进行受体介导内吞过程中细胞内ｐＨ值的变化。结果显示，开始内吞后细胞内ｐＨ值即降低，内吞进行到第５分钟细胞内ｐＨ值降到最低，在此后的６分钟内均维持于这一较低水平。本法灵敏度高，简便快捷，适用范围广，可无损伤观察活细胞或细胞器ｐＨ值的变化。     

pH值影响细菌内毒素测定的实验室研究

 目的：研究样品pH对细菌内毒素测定的影响。方法：应用动态浊度法定量测定样品中细菌内毒素的含量；由细菌内毒素参考标准品(RSE)制成两种浓度的稀释液，在14个pH量级上，与国内外两种鲎试剂(TAL,Tal)反应；观察每组平均回收率。结果：pH梯度上，两种鲎试剂回收曲线都呈现三个反应高峰，分别为pH5.20,pH7.83/pH6.23和pH10.55。样品pH在6～8间实验结果稳定，4λ阳性对照的平均回收率为76.5%～115.9%和85.8%～99.8%；当样品pH值≤3或≥12时，细菌内毒素试验受到抑制，平均回收率≤56.8%。结论：细菌内毒素试验中应该调节检品pH；使用TAL时，检品pH应预调在(6.5～7.5)为好；使用LAL时，检品pH应预调在(6.2±0.1)或(6.7～7.8)为好。     

羟基红花黄色素(HSYA)纯化条件的影响

目的探讨纯化羟基红花黄色素A（HSYA）的影响因素。方法用HPLC法测定，以HSYA百分舍量为指标，考查醇沉浓度．药液浓度及pH值对HSYA纯化的影响。结果醇沉浓度对HSYA的纯化影响较大，其次为药液浓度和pH值，而且先调pH值后醇沉得到的HSYA舍量更高。结论80％的乙醇沉淀．药液浓度为料液比2：1，pH值为6．5，是最佳工艺条件。     

主动载药法制备盐酸去氢骆驼蓬碱脂质体

目的制备高包封率的盐酸去氢骆驼蓬碱脂质体。方法处方前研究测定了药物在不同pH值缓冲液中的溶解度和表观油水分配系数;采用pH梯度进行主动载药。超滤法分离脂质体与游离药物,测定包封率,考察了外水相pH值、孵育温度、药脂比对包封率的影响。结果随pH值的增大,盐酸去氢骆驼蓬碱的溶解度降低,表观油水分配系数增大;采用主动载药法,包封率随脂质体内外相pH梯度的减少而降低,受孵育温度的影响不大,在药脂比小于1∶5时脂质体包封率达到80%以上。结论主动载药法可制得包封率较高的去氢骆驼蓬碱脂质体。     

Extracellular acidification decreases the basal motility of cultured mouse microglia via the rearrangement of the actin cytoskeleton

The present study was undertaken to examine the effect of extracellular pH (pH(0)) on the locomotor function of murine microglial cells in vitro. We have found that basal motility of microglia, as measured by a computer-assisted video assay, decreased in an acidic, but not in an alkaline environment. Extracellular acidification affected the architecture of F-actin cytoskeleton, inducing bundling of actin and the formation of stress fibers. The change in intracellular pH (pH(i)) resulting from the change in pH(0) seems to be a prerequisite for the motility decrease since other means to decrease pH(i), namely Na(+)-free solution (in the absence of HCO(-)(3)) and nigericin-containing solution, mimicked the extracellular acidification. In contrast to its pronounced effect on basal motility of microglial cells, the motility increase, as induced by the chemoattractant complement 5a (C5a), was not affected by the acidic environment. The relationship of pH(0) to the locomotor function was also studied in a long-term microchemotaxis assay where microglia migrated within a pH gradient. Intracellular acidification induced by lowering pH(0) to 6.0 or removal of Na(+) from the assay medium decreased basal microglial cell migration. The C5a-induced chemotactic migration was moderately decreased by the acidic environment. In conclusion, our results suggest that acidification of the microglial extracellular milieu leads to a decrease in pH(i) and thereby reduces the basal microglial motility and C5a-induced chemotaxis via a rearrangement of the cytoskeleton. We would therefore like to speculate that changes in pH(i) constitute an important control mechanism in regulating the locomotor function of microglia in culture and probably also in the intact tissue.     

Alteration of intracellular pH and activity of CA3-pyramidal cells in guinea pig hippocampal slices by inhibition of transmembrane acid extrusion

Transmembrane acid extruders, such as electroneutral operating Na(+)/H(+)-exchangers (NHE) and Na(+)-dependent Cl(-)/HCO(3)(-)-exchangers (NCHE) are essential for the maintenance and regulation of cell volume and intracellular pH (pH(i)). Both of them are hypothesised to be closely linked to the control of excitability. To get further information about the relation of neuronal pH(i) and activity of cortical neurones we investigated the effect of NHE- and/or NCHE-inhibition on (i) spontaneous action potentials and epileptiform burst-activity (induced by bicuculline-methiodide, caffeine or 4-aminopyridine) and (ii) on pH(i) of CA3-neurones. NHE-inhibition by amiloride (0.25-0.5 mM) or its more potent derivative dimethylamiloride (50 microM) and NCHE-inhibition by 4,4'-diisothiocyanostilbene-2,2'-disulfonic acid (DIDS, 0.25-0.5 mM) induced a biphasic alteration of neuronal activity: an initial, up to 30 min lasting, increase in frequency of action potentials and bursts preceded a growing and partially reversible suppression of neuronal activity. In BCECF-loaded neurones the pH(i), however, continuously decreased during either amiloride- or DIDS-treatment and reached its steady-state (DeltapH(i) up to 0.3 pH-units) when the neuronal activity was markedly suppressed. Combined treatment with amiloride (0.5 mM) and DIDS (0.5 mM) or treatment with harmaline alone (0.25-0.5 mM), which also continuously acidified neurones via inhibition of an amiloride-insensitive NHE-subtype, induced a monophasic and partially reversible suppression of neuronal activity. As an initial excitatory period failed to occur during combined NHE/NCHE-inhibition we speculate that its occurrence during amiloride- or DIDS-treatment resulted rather from disturbances in volume- than in pH(i)-regulation. The powerful inhibitory and anticonvulsive properties of NHE- and NCHE-inhibitors, however, very likely based upon intracellular acidification - as derived from our previous findings that a moderate increase in intracellular free protons is sufficient to reduce membrane excitability of CA3-neurones.     

一种新的双向电泳蛋白样品制备方法

目的探讨双向凝胶电泳（2-DE）样品裂解液对蛋白质分离和双向凝胶电泳结果的影响。方法以MOLT-4细胞为例，采用3种溶解性能不同的裂解液提取细胞中的蛋白质组，并分别进行双向聚丙烯酰胺凝胶电泳。结果通过对2-DPAGE图谱的比较分析，发现采用8mol／L Urea，2mol／L Thiourea，4％CHAPS，1％NP-40.4％Triton X-100，65mmol／LDTT，0．5mmol／LPMSF，0．5％pharmalyte3-10，能获得质量较高的2-DE图谱。结论采用高浓度脲、三去污裂解液有利于获得优质的蛋白质样品，从而提高蛋白质提取率和双向电泳分辨率等。