Effects of lead,copper, and zinc on the rat's lactate dehydrogenase in vivo and in vitro

Following subacute intoxication of rats with Pb-, Cu-, and Zn-salts (separately or in mixture) for 5 weeks, the chelating agent D-penicillamine was administered for 3 weeks. In the course of the 3-month experiment, lactate dehydrogenase (LDH) was estimated in serum and in cytoplasmic fraction of the kidney. Pb²⁺ treatment resulted in an increase of LDH activity, Cu²⁺ in a slight decrease, whereas Zn²⁺ had no effect, respectively. Mixture of these metals caused a significant rise in the enzymatic activity. Seven weeks after the stoppage of the administration of toxic substances, altered LDH activity, both in serum and in kidney returned to normal. D-penicillamine treatment was found to accelerate a restoration of the enzyme activity.In the experiments in vitro, Cu²⁺ inhibited significantly the kidney LDH activity, Pb²⁺ and Zn²⁺ being 100- and 400-times less efficient, respectively. Cu²⁺ inhibition was reversed by D-penicillamine, whereas inhibition of LDH by Zn²⁺ or Pb²⁺ was irreversible.     

Early postnatal maturation of GABAA-mediated inhibition in the brainstem respiratory rhythm-generating network of the mouse

It is well established that GABA_A‐mediated postsynaptic potentials are excitatory in many brain regions during embryonic and early postnatal life. The pre‐Bötzinger complex (PBC) in the brainstem is an essential component of the respiratory rhythm‐generating network, where GABA_A‐mediated inhibition plays a critical role in generating a stable respiratory rhythm in adult animals. In the present study, using the perforated patch technique, we investigated the maturation of GABA_A receptor‐mediated effects on rhythmically active PBC neurons and on the motor output in slice preparations from P0–15 neonatal mice. The reversal potential of GABA_A receptor‐mediated current (E_GABA‐A) switched from depolarizing to hyperpolarizing within the first postnatal week. E_GABA‐A was ?13.7 ± 9.8 mV at P0, then it changed to ?44.8 ± 7.0 mV at P2 and ?71.5 ± 6.8 mV at P4. Perfusion of bicarbonate‐free saline has no detectable influence on E_GABA‐A, indicating that a lack of Cl^– extrusion during P0–3 is mainly responsible for early GABA_A‐ergic excitation. At the network level, blockade of GABA_A receptors with bicuculline did not significantly change the frequency of rhythmic bursts recorded from hypoglossal nerve roots before P3, whereas it increased the coefficient of variation. After P3, bicuculline increased burst frequency with little effect on the coefficient of variation. Thus, chloride‐mediated inhibition, which appears in PBC neurons after P3, coincides with the appearance of GABA_A‐mediated modulation of the respiratory rhythm. GABA_A receptor‐activated inhibition may therefore be necessary for frequency modulation in the respiratory network beginning on the fourth postnatal day in the mouse brainstem.     

胞磷胆碱钠氯化钠注射液及其注射液细菌内毒素检查法的研究

目的:胞磷胆碱钠氯化钠注射液是一种新型制剂,我们对其进行了细菌内毒素检查方法的研究,同时对原剂型胞磷胆碱钠注射液也进行了该方法研究。方法:对五个厂家的10批样品,采用不同生产厂家和规格的TAL,进行了干扰试验和细菌内毒素检查。结果:本品高浓度时对TAL与细菌内毒素的凝集反应有干扰作用,经稀释后可排除。结论:本品的不干扰浓度,以胞磷胆碱钠计为0.25mg·ml~(-1),可采用细菌内毒素检查法进行质量控制。     

复方毛冬青注射液与3种输液配伍后的微粒及其pH值观察

目的　观察复方毛冬青注射液分别与 0 9%氯化钠注射液、10 %葡萄糖注射液和小儿用葡萄糖氯化钠注射液 3种输液配伍时的不溶性微粒及其pH值变化。方法　不同剂量 ( 4、6、8和 10ml)的复方毛冬青注射液分别与 10 0ml上述输液配伍 ,混合液的不溶性微粒利用微粒分析仪测定 ,以及其 pH值利用pH/离子计仪测定。 结果　不同剂量复方毛冬青注射液与各输液混合其 4个通道 (≥ 2 5 μm、≥ 10 μm、≥ 5 μm、≥ 2 μm)的不溶性微粒均显著性增多 (P <0 .0 1) ,且其pH也有明显变化。 结论　复方毛冬青注射液与 3种输液配伍的不溶性微粒不符合中国药典及英国药典的质量标准 ,应引起重视。建议在临床应用时可在其一次性输液器加装有效的终端滤器     

透析液中氯化钾含量测定方法的改进

目的：改进透析液中氯化钾含量测定方法提高回收率。方法：将原方法中四苯硼钠的浓度增加到0．02mol／l。结果：测得的回收率从原来的94．79％增加以100．15％。结论：改进后的方法准确、可靠。     

特异性鲎试剂分析甘露聚糖肽氯化钠注射液的细菌内毒素

目的　考察甘露聚糖肽氯化钠注射液进行细菌内毒素检查的可行性。方法　应用普通鲎试剂及特异性鲎试剂对样品进行内毒素的定性及定量检查。结果　甘露聚糖肽氯化钠注射液经 6倍稀释后对普通鲎试剂的细菌内毒素检查有明显的干扰作用 ,而对特异性鲎试剂无干扰作用 ;以特异性鲎试剂检查 6批样品其细菌内毒素含量均小于 15 0 0EU·L-1,凝胶法和动态浊度法鲎试验均证实了这一点。结论　必须应用特异性鲎试剂检查甘露聚糖肽氯化钠注射液中的细菌内毒素以排除其干扰作用     

氯化铝对大鼠皮层神经元凋亡及bc1-2、bax基因表达的影响

目的　探讨氯化铝 (AlCl3)对大鼠皮层神经元凋亡的诱导作用及对bc1 2、bax基因表达的影响。方法　体外原代无血清培养至第 7天的大鼠皮层神经元 ,实验组的培养液中加入AlCl3(终浓度分别为 10、10 0、10 0 0 μmol L) ,对照组的培养液中加入等体积分数为 0 9%的生理盐水 ,培养 48h后 ,用原位末端标记法 (TUNEL)测定其细胞凋亡率 ;培养 2 4h后 ,用RT PCR法检测bc1 2、bax基因的表达。结果　各染铝组大鼠皮层神经元凋亡率明显升高 ,与对照组相比 ,差异有显著性 (P <0 0 5 ) ,并具有明显的剂量 反应关系 ;bc1 2基因表达明显下降 ,bax基因表达明显升高 ,bc1 2 bax逐渐下降 ,与对照组相比 ,差异有显著性 ,也具有明显的剂量 反应关系。相关分析表明 ,大鼠皮层神经元凋亡率与bc1 2基因表达呈负相关 ,与bax基因表达呈正相关 ,而与bc1 2 bax呈负相关 (P <0 0 1)。结论　铝可以诱导大鼠皮层神经元凋亡 ,其机制可能与bc1 2基因表达下调 ,bax基因表达上调以及bc1 2 bax下降有关。     

丙烯酸树脂水性包衣工艺制备氯化钾缓释片的研究

目的:研究氯化钾缓释片的优化工艺.方法:采用丙烯酸树脂水性包衣工艺,通过体外溶出试验对工艺参数进行筛选.结果:包衣后热处理、包衣处方因数(聚合物配比、增塑剂、包衣增重等)都对缓释片释放度有影响,而浆法转速和介质渗透压对缓释片释放度几乎无影响.结论:本研究缓释片的体外释放按零级模式释药.     

酶电极法测定氯化琥珀胆碱注射液氯化胆碱及氯化琥珀胆碱含量

 目的：测定氯化琥珀胆碱注射液中氯化胆碱与氯化琥珀胆碱含量。方法：以固定化胆碱氧化酶（EC5896）结合H₂O₂电极构成电流型酶电极生物传感分析仪并与银量法对比测定。结果：酶电极法测定线性范围：0mg·L^－1～200mg·L^－1，精度RSD＜1．5％，响应时间：40s，固定化胆碱氧化酶膜使用寿命大于60d，实际测定氯化琥珀胆碱注射液中氯化胆碱含量；回收率：100．3％～102．3％。与银量法对比测定，两法测定结果的相关系数r＝0．9929。结论：采用酶电极法能准确测定氯化琥珀胆碱注射液中氯化胆碱及氯化琥珀胆碱含量。     

HPLC法测定两面针中氯化两面针碱的含量

建立了两面针中氯化两面针碱的HPLC测定法，方法简便、准确。加样回收率为97.7％，RSD＝0．82％，最低检测浓度0．8μg／mL，可用于两面针的质量控制。