Über den Einfluss von Natriumsulfit,Natriumtellurit und Natriumselenit auf die Retention von Zink,Kadmium und Quecksilber im Organismus

Summary The influence of sodium sulfite, sodium tellurite and sodium selenite on the retention of zinc, cadmium and mercury in mice was studied. The retention of mercury was increased by sodium selenite and by sodium tellurite. The retention of cadmium was increased only by sodium selenite. Sodium sulfite did not influence the retention of metals studied. The retention of zinc was not influenced by any compounds used.     

Fungitoxicity of m-fluorophenylalanine-containing peptides towards Pythium ultimum

The tripeptide L-m-fluorophenylalanyl-L-alanyl-L-alanine was much more fungitoxic towards Pythium ultimum than the dipeptide L-m-fluorophenylalanyl-L-alanine or m-fluorophenylalanine. The fungitoxicity of the tripeptide was reduced by L-alanyl peptides and phenylalanine, but not by other amino acids. In contrast, the fungitoxicity of m-fluorophenylalanine was unaffected by peptides, and was antagonized by several amino acids. These results suggest the effective delivery of m-fluorophenylalanine into the cell by a tripeptide carrier.     

Adrenaline and the electrogenic sodium pump in Rana catesbeiana sympathetic ganglion cells.

The effect of adrenaline on the Na+-pump in bullfrog (Rana catesbeiana) sympathetic ganglion cells was studied by use of electrophysiological methods. The rate of removal of excess Na+ injected into a ganglion cell was increased by adrenaline. The K+-activated hyperpolarization of cell membrane, which might be produced by an electrogenic Na+-pump, was also increased by adrenaline. These results suggested that adrenaline was able to accelerate the Na+-pump, possibly the electrogenic Na+-pump.     

超临界CO2萃取法提取库尔勒香梨精油及其成分分析研究

采用超临界CO2萃取法提取库尔勒香梨精油,用气相色谱-串联质谱技术对其成分进行分析,并对几种提取方法进行综合比较。结果表明,与水蒸气蒸馏法、固相微萃取法相比,超临界CO2萃取法具有香梨精油提取率最高,为0．0549％。感官分析的结果表明,超临界CO2萃取法所得的库尔勒香梨精油颜色为橙色透明液体,而且风味好。气相色谱-质谱联用（GC-MS）分析结果表明：超临界CO2萃取法所得的香梨精油中共鉴定出28种成分。丁酸乙酯、顺-7-十四烯-1-醇和乙酸己酯的含量最高,含量分别为5．19％、4．85％和4．37％。     

Participation of microtubules and microfilaments in the transcellular biliary secretion of immunoglobulin A in primary cultures of rat hepatocytes

Summary The biliary secretion of immunoglobulin A (IgA) in primary hepatocyte cultures was investigated by means of immunofluorescence. The characteristic accumulation of IgA in visible bile canaliculi was found to be strongly inhibited by vinblastine and colchicine or by cytochalasin B, but its surface binding was not.The author thanks Prof. Dr D. Mecke for his support and encouragement. The excellent technical assistance of Mrs M. Behringer and Mrs A. Schneck is gratefully acknowledged. The author is grateful to the BIOTEST Serum Institut (Frankfurt) for the kind gift of human IgA. This work was supported by the Deutsche Forschungsgemeinschaft.     

纤维素分解混合菌群的筛选及腐解稻草研究Ⅱ纤维素分解混合菌群对稻草的腐解

对富集筛选的纤维素分解混合菌群进行了稻草腐解试验,结果表明：施用该纤维素分解混合菌群后能够减少氨态氮素的挥发,纤维素分解混合菌群在15d内对稻草的腐解效果明显,外观分散度明显比对照要好,对照的失重率为45．80％,而处理的失重率为57．85％,比对照提高了12．05个百分点。Duncan新复极差法分析表明,失重率在1％水平差异极显著,而还原糖量、纤维素酶活以及pH值的差异均不显著,说明还原糖量、纤维素酶活以及pH值不能作为判断稻草腐解程度的指标。得到了一个稻草腐解效果较好的混合菌群,能够在外界菌群存在的条件下较好腐解稻草。     

Activation of the electrogenic Na-pump of cardiac muscle fibres by ACh in K-free solutions

Summary The ionic mechanism of the membrane outward current (ACh-current) of bullfrog atrium muscle, induced by acetylcholine in K-free solution, was analyzed by a voltage-clamp experiment. The results suggested that the ACh-current was induced not only by an increase in K-conductance but also by an activation of the electrogenic Na-pump.Acknowledgment. This work was supported by a grant (257037) from the Ministry of Education of Japan.     

Inhibition of E coli ATPase activity by a troponin component, TN-I, and by mitochondrial ATPase inhibitor.

The enzymic activity of Mg2+- or Ca2+-stimulated ATPase from Escherichia coli was inhibited by one of the troponin components, TN-I, and by mitochondrial ATPase inhibitor (F1-inhibitor). The inhibitory ability of component TN-I against Mg2+-stimulated AtPase activity was lost after digestion of component TN-I with trypsin. The Mg2+-stimulated ATPase activity inhibited by component TN-I was completely restored by the addition of another troponin component TN-C.     

A promoting action of cyclic GMP on contractions of guinea-pig vas deferens

Summary The effect of dbc-GMP has been studied in ductus deferens of the guinea-pig. The nucleotide potentiated the contractions induced by electrical field stimulation and by adrenergic agonists. The site of action was probably in the smooth muscle cell, since the release of excitatory transmittor was not influenced.This work was supported by the Swedish State Medical Research Council (04X-4498).     

Effects and duration of resistance acquired by rabbits on feeding and egg laying in Ixodes ricinus L.

Summary Rabbits gradually developed a resistance against Ixodes ricinus ticks as a result of sequential experimental infestations. The resistance was characterized by an increased duration of feeding, by ticks engorging to a smaller extent and by reduced egg production. Once established, the immunity persisted for at least 9 months. Changes in the titre of circulating anti-I. ricinus antibodies was measured by indirect immunofluorescence.The present work was supported by the Swiss National Fund for Scientific Research, grant No. 3.558-0.75.     

Existence of several non-specific recognition systems in macrophages]

Rat peritoneal cells were made to bind five particle species: immunoglobulin-coated Sheep red cells, glutaraldehyde-treated Sheep red cells, latex beads, leishmania and tumor cells. The dependence of binding on various physico-chemical parameters was studied. The binding of latex beads or Leishmania was not inhibited by cold (4 degrees C), sodium azide, cytochalasin B and ethyleneglycol or dimethylsulphoxide. The binding of immunoglobulin-coated Sheep red cells was unaffected by cold and azide, but it was inhibited by cytochalasin B, ethyleneglycol and dimethylsulphoxide. The binding of glutaraldehyde-treated Sheep red cells was inhibited by cold, azide and ethyleneglycol, but it resisted cytochalasin B and dimethylsulphoxide. The binding of tumor cells was inhibited by azide, cytochalasin B, ethyleneglycol and dimethylsulphoxide. It is concluded that: (a) macrophages are endowed several sets of non-specific binding structures that are differently affected by physico-chemical parameters, which provides a simple way of characterizing them; (b) the expression of a given binding structure on the macrophage membrane is modulated by metabolic inhibitors; (c) some lymphocytes were able to bind tumor cells or Leishmania. Thus, lymphocytes and macrophages might share some non-specific adhesive structures.     

携SiRNA的聚乳酸羟基乙酸微球对Bel-7402/5-Fu细胞MDR1基因沉默作用的研究

目的 探讨携SiRNA的聚乳酸羟基乙酸(PLGA)微球通过沉默肝癌耐药细胞多药耐药基因(MDR1)基因,实现肝癌耐药的逆转.方法 合成针对MDR1的RNA干扰小片段(SiRNA),通过超声复乳法制备携药微球,转染肝癌耐药细胞Bel-7402/5 -Fu.运用Real-time PCR与Western blot方法,通过检测其mRNA及P糖蛋白表达水平,评价RNA干扰对MDR1表达的影响.MTT法检测RNA干扰逆转Bel-7402/5 Fu细胞对药性的效果,通过实验组细胞和对照组细胞之间的半数抑制剂量(IC50),计算RNA干扰组细胞的耐药逆转倍数.结果 在肝癌耐药细胞Bel-7402/5-Fu中,RNA干扰明显抑制了MDR1 mRNA和蛋白产物P糖蛋白的表达水平,且出现了P糖蛋白的持续低表达.MTT法显示,相同药物浓度下,实验组细胞生长明显受到抑制,表明其耐药性明显下降,其对药逆转倍数为11.56.结论 携SiRNA的PLGA微球能够有效减少肝癌耐药细胞Bel-7402/5-Fu的MDR1mRNA及P糖蛋白的表达水平,降低其耐药性.     

Uptake and toxic effects of heavy metal ions: interactions among cadmium, copper and zinc in cultured cells

Absorption of metal ions by KB, HeLa and L-59 cells has been analyzed by atomic absorption spectrophotometry in the course of culture. Ions of the elements of the fourth period in the periodic chart such as Fe(II), Cu(II), Zn(II), Mn(II) and Ni(II) were not taken up, but those of the higher periods, such as Cd(II), Pb(II), Hg(II) and Ag(I) were were taken up easily. The uptake behavior by the cultured cells was in accordance with the characteristic features of metals, that metals in the fourth period are essential elements, and most of the elements of the fifth and the sixth periods are non-essential or toxic elements. The initial rate of Cd(II) uptake and the Cd(II) concentration has a sigmoidal relationship. Cd(II) was absorbed homotropically through cell membranes. The uptake of Cd(II) was specifically inhibited by Cu(II), but was affected little by Zn(II). The toxicity of Cd(II) to KB cells was greatly enhanced in the presence of Cu(II). On the contrary, the toxicity of Cd(II) was reduced by the addition of Zn(II) at several concentrations of Cd(II). The toxicity of Cd(II) did not depend on the amount of Cd(II) absorbed in the cells, but was determined by cofactors such as Cu(II). The interaction between Cd(II) and Cu(II) may be important for Itai-itai disease.     

Monoamine oxidase activity of the hypothalamus and pituitary: alterations after pinealectomy, changes in photoperiod, or additions of melatonin in vitro.

Rat pituitary MAO activity was reduced by constant darkness and by additions of melatonin in vitro and was increased by constant light and by pinealectomy. Hypothalamic MAO activity followed the same pattern but was less dramatically affected. The data suggest that MAO may be a target enzyme for melatonin.     

Activation of the electrogenic Na-pump of cardiac muscle fibres by ACh in K-free solutions.

The ionic mechanism of the membrane outward current (ACh-current) of bullfrog atrium muscle, induced by acetylcholine in K-free solution, was analyzed by a voltage-clamp experiment. The results suggested that the ACh-current was induced not only by an increase in K-conductance but also by an activation of the electrogenic Na-pump.     

Effect of oridonin, a Rabdosia diterpenoid, on radiosensitization with misonidazole

The radiosensitization brought about by oridonin, one of the Rabdosia diterpenoids, alone or in combination with misonidazole, was investigated in Chinese hamster V79 cells. The enhancement ratio of 1.92 was obtained when 0.01 mM oridonin and 1 mM misonidazole were administered to hypoxic cells under radiation. The enhancement ratios of oridonin and misonidazole for hypoxic cells were 1.16 and 1.59 respectively. Hence, a supra-additive effect was obtained by the combined treatment with these two drugs. Under aerobic conditions, no effect of 0.01 mM oridonin on the radiosensitization caused by misonidazole was observed.     

Inhibition of human platelet lipoxygenase by cyanide

Summary Potassium cyanide inhibited the lipoxygenase activity of a human platelet cytosolic fraction in a concentration-dependent manner (ID₅₀=2 mM). The inhibition was monitored by spectrophotometry (conjugation of diene bonds at 236 nm), by chromatography (inhibition of formation of 12-hydroperoxy eicosatetraenoic acid) as well as by measuring suppression of oxygen consumption. The lipoxygenase activity of intact platelets was also inhibited by KCN as evidenced by the reduction in 12-hydroxy-eicosatetraenoic acid formation in response to thrombin.Acknowledgments. This work was supported in part by NIH grant HL-14890. D.A. was a recipient of the Pharmaceutical Manufacturers Association Advanced Pre-Doctoral Fellowship.     

Liver function during chronic renal failure in rabbits

In rabbits with chronic renal insufficiency the prothrombin index was increased by 25% and the alanine aminotransferase activity decreased by 20%; the results of other routine tests of hepatic function were not affected. The galactose elimination capacity was decreased by 12%, whereas the body clearance of antipyrine was unchanged. No change in hepatocytic structure was found.     

Direct observation of the NAD glycohydrolase reaction in human erythrocytes using NMR spectroscopy

Summary The hydrolysis of NAD by the extracellular membrane-associated enzyme NAD glycohydrolase was shown to be readily followed in concentrated suspensions of human erythrocytes using¹H spin-echo nuclear magnetic resonance spectroscopy (NMR). The maximal rate of the reaction was determined and the inhibitory effect of nicotinamide was confirmed by direct NMR observation. In addition, arginine, ergothioneine and iodoacetate did not influence the reaction rate.³¹P NMR analyses of reaction media from whole cells showed that no extraneous degradation of NAD occurred and the only phosphate-containing product was ADP-ribose.The work was supported by the Australian National Health and Medical Research Council     

Uptake and toxic effects of heavy metal ions: Interactions among cadmium,copper and zinc in cultured cells

Summary Absorption of metal ions by KB, HeLa and L-59 cells has been analyzed by atomic absorption spectrophotometry in the course of culture. Ions of the elements of the fourth period in the periodic chart such as Fe(II), Cu(II), Zn(II), Mn(II) and Ni(II) were not taken up, but those of the higher periods, such as Cd(II), Pb(II), Hg(II) and Ag(I) were were taken up easily. The uptake behavior by the cultured cells was in accordance with the characteristic features of metals, that metals in the fourth period are essential elements, and most of the elements of the fifth and the sixth periods are non-essential or toxic elements.The initial rate of Cd(II) uptake and the Cd(II) concentration has a sigmoidal relationship. Cd(II) was absorbed homotropically through cell membranes. The uptake of Cd(II) was specifically inhibited by Cu(II), but was affected little by Zn(II). The toxicity of Cd(II) to KB cells was greatly enhanced in the presence of Cu(II). On the contrary, the toxicity of Cd(II) was reduced by the addition of Zn(II) at several concentrations of Cd(II). The toxicity of Cd(II) did not depend on the amount of Cd(II) absorbed in the cells, but was determined by cofactors such as Cu(II). The interaction between Cd(II) and Cu(II) may be important for Itai-itai disease.