Bioelectrochemistry and bioenergetics (Lausanne, Switzerland)最新文献_第8页

Chinese hamster ovary cells sensitivity to localized electrical stresses 中国仓鼠卵巢细胞对局部电应激的敏感性

Bioelectrochemistry and bioenergetics (Lausanne, Switzerland) Pub Date : 1999-02-01 DOI: 10.1016/S0302-4598(98)00239-6

M.-C Vernhes , P.-A Cabanes , J Teissie

{"title":"Chinese hamster ovary cells sensitivity to localized electrical stresses","authors":"M.-C Vernhes , P.-A Cabanes , J Teissie","doi":"10.1016/S0302-4598(98)00239-6","DOIUrl":"10.1016/S0302-4598(98)00239-6","url":null,"abstract":"<div><p>Application of an external electric field on a cell suspension induces an alteration in the membrane structure giving free access to the cell cytoplasm. Under mild pulsation conditions, permeabilization is a reversible process which weakly affects cell viability while drastic electrical conditions lead to cell death. The field pulse must be considered as a complex stress applied on the cell assembly. This study is a systematic investigation of the stress effects of field strength, pulse duration and number of pulses, at given joule energy. The loss in cell viability is not related to the energy delivered to the system. At a given joule energy, a strong field during a short cumulated pulse duration affects more viability than using a weak field associated with a long cumulated pulsation. At a given field strength and for a given cumulated pulse duration an accumulation of short pulses is also observed to be very damaging for cells. A control by the delay between the pulses suggests a memory effect. The field effect appears also to be vectorial in line with the known asymmetry of the membrane organization. These results suggest that processes at a cellular level are involved, either an activation of cell death or damage in cellular functions.</p></div>","PeriodicalId":79804,"journal":{"name":"Bioelectrochemistry and bioenergetics (Lausanne, Switzerland)","volume":"48 1","pages":"Pages 17-25"},"PeriodicalIF":0.0,"publicationDate":"1999-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/S0302-4598(98)00239-6","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"21098941","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 60

EMF signals and ion/ligand binding kinetics: prediction of bioeffective waveform parameters 电磁场信号和离子/配体结合动力学:生物有效波形参数的预测

Bioelectrochemistry and bioenergetics (Lausanne, Switzerland) Pub Date : 1999-02-01 DOI: 10.1016/S0302-4598(98)00148-2

A.A Pilla , D.J Muehsam , M.S Markov , B.F Sisken

{"title":"EMF signals and ion/ligand binding kinetics: prediction of bioeffective waveform parameters","authors":"A.A Pilla , D.J Muehsam , M.S Markov , B.F Sisken","doi":"10.1016/S0302-4598(98)00148-2","DOIUrl":"10.1016/S0302-4598(98)00148-2","url":null,"abstract":"<div><p>The kinetics of an electromagnetic field (EMF) target pathway are used to estimate frequency windows for EMF bioeffects. Ion/ligand binding is characterized via first order kinetics from which a specific electrical impedance can be derived. The resistance/capacitance properties of the binding pathway impedance, determined by the kinetics of the rate-determining step, define the frequency range over which the target pathway is most sensitive to external EMF. Applied signals may thus be configured such that their spectral content closely matches that of the target, using evaluation of the signal to thermal noise ratio to optimize waveform parameters. Using the approach proposed in this study, a pulsed radio frequency (PRF) waveform, currently employed clinically for soft tissue repair, was retuned by modulation of burst duration, producing significant bioeffects at substantially reduced signal amplitude. Application is made to Ca<sup>2+</sup>/Calmodulin-dependent myosin phosphorylation, for which the binding time constants may be estimated from reported kinetics, neurite outgrowth from embryonic chick dorsal root explants and bone repair in a fracture model. The results showed that the retuned signal produced increased phosphorylation rates, neurite outgrowth and biomechanical strength that were indistinguishable from those produced by the clinical signal, but with a tenfold reduction in peak signal amplitude, ≈800-fold reduction in average amplitude and ≈10<sup>6</sup>-fold reduction in average power.</p></div>","PeriodicalId":79804,"journal":{"name":"Bioelectrochemistry and bioenergetics (Lausanne, Switzerland)","volume":"48 1","pages":"Pages 27-34"},"PeriodicalIF":0.0,"publicationDate":"1999-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/S0302-4598(98)00148-2","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"21098942","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 65

Is genetics the unrecognized confounding factor in bioelectromagnetics? Flock-dependence of field-induced anoxia protection in chick embryos 遗传学是生物电磁学中未被认识到的混淆因素吗?鸡胚野外缺氧保护的群体依赖性

Bioelectrochemistry and bioenergetics (Lausanne, Switzerland) Pub Date : 1999-02-01 DOI: 10.1016/S0302-4598(98)00213-X

A.L Di Carlo , T.A Litovitz

{"title":"Is genetics the unrecognized confounding factor in bioelectromagnetics? Flock-dependence of field-induced anoxia protection in chick embryos","authors":"A.L Di Carlo , T.A Litovitz","doi":"10.1016/S0302-4598(98)00213-X","DOIUrl":"10.1016/S0302-4598(98)00213-X","url":null,"abstract":"<div><p>Work in bioelectromagnetics has long been plagued by problems with replication. This includes experiments done on electromagnetic (EM) field-induced effects in chick embryos. Our laboratory investigated responses of embryos from two flocks of White Leghorn hens. Both flocks were studied simultaneously, and it was found that they responded differently to EM field exposures. Embryos were exposed to 60 Hz, 8 μT EM fields prior to placement in an anoxic chamber. Following re-oxygenation, survival in controls was 34.6%, exposed flock 1 survival was 62% (<em>P</em><0.0001) and exposed flock 2 survival was 43% (<em>P</em><0.0136). <em>P</em> values are from comparison of data between EM field exposed embryos (flocks 1 and 2) versus controls. In order to induce maximum protection in flock 2, (≈62% survival), embryos required a longer exposure time at higher magnetic field strengths. These results reinforce the concepts that genetics are important in determining whether or not chick embryos will respond to EM field stimulation. A broader look at the role of genetic factors emphasizes that these variations in response to external stimuli (e.g., drugs, radiation, and EM fields) are found in all areas of biological research (cell culture, chick, rat, and human studies). The present study suggests that genetics may be a prime cause of the difficulties encountered in replication studies in the field of bioelectromagnetics. We conclude that replication studies should not be undertaken unless care is taken to insure that exactly the same strains of cells or animals are used. Researchers should also first confirm that the responses of their model to non-EM field stimuli are similar to that obtained in the original study.</p></div>","PeriodicalId":79804,"journal":{"name":"Bioelectrochemistry and bioenergetics (Lausanne, Switzerland)","volume":"48 1","pages":"Pages 209-215"},"PeriodicalIF":0.0,"publicationDate":"1999-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/S0302-4598(98)00213-X","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"21099370","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 19

Dose–response of electromagnetic field-enhanced ornithine decarboxylase activity 电磁场增强鸟氨酸脱羧酶活性的剂量响应

Bioelectrochemistry and bioenergetics (Lausanne, Switzerland) Pub Date : 1999-02-01 DOI: 10.1016/S0302-4598(98)00229-3

J.M Mullins , L.M Penafiel , J Juutilainen , T.A Litovitz

引用次数: 48

Polarographic properties and potential carcinogenicity of some natural nucleosides and their synthetic analogues 一些天然核苷及其合成类似物的极谱性质和潜在致癌性

Bioelectrochemistry and bioenergetics (Lausanne, Switzerland) Pub Date : 1999-02-01 DOI: 10.1016/S0302-4598(99)00005-7

Ladislav Novotny , Anna Vachalkova , Alois Piskala

{"title":"Polarographic properties and potential carcinogenicity of some natural nucleosides and their synthetic analogues","authors":"Ladislav Novotny , Anna Vachalkova , Alois Piskala","doi":"10.1016/S0302-4598(99)00005-7","DOIUrl":"10.1016/S0302-4598(99)00005-7","url":null,"abstract":"<div><p>The polarographic reduction and the index of potential carcinogenicity tg <em>α</em> determined polarographically in aprotic conditions and in the presence of α-lipoic acid of nine naturally occurring and synthetic pyrimidine and six synthetic 1,3,5-triazine (5-aza) nucleosides was compared to the reduction of eight synthetic 1,3,6-triazine (6-aza) nucleosides. Nucleosides are of interest because of their key role in the nucleic acid structure and because of the antimetabolite and cytotoxic/antileukemia properties of their synthetic analogues. It was shown that polarographic reduction of the studied compounds is achieved at gradually increased potentials in the order of 6-aza<5-aza<pyrimidine nucleosides. On other hand, the potential carcinogenicity of studied compounds increases usually in the order of pyrimidine<6-aza≪5-aza nucleoside. The only compounds with remarkable potential carcinogenicity identified at this study were those ones from the 5-aza (1,3,5-triazine) antimetabolite series - arabinosyl-5-azacytosine (0.275), 5-aza-cytidine (0.295) and 5-aza-uracil (0.400) - and 2,2′-anhydrouridine (0.260). The relation of the data obtained to biological activity of nucleosides included in the study is discussed.</p></div>","PeriodicalId":79804,"journal":{"name":"Bioelectrochemistry and bioenergetics (Lausanne, Switzerland)","volume":"48 1","pages":"Pages 129-134"},"PeriodicalIF":0.0,"publicationDate":"1999-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/S0302-4598(99)00005-7","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"21098291","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 6

Study on the direct electron transfer process of superoxide dismutase 超氧化物歧化酶直接电子转移过程的研究

Bioelectrochemistry and bioenergetics (Lausanne, Switzerland) Pub Date : 1999-02-01 DOI: 10.1016/S0302-4598(98)00233-5

Xia-Qin Wu, Xiao-Yun Meng, Zhe-Su Wang, Zong-Rang Zhang

引用次数: 21

Surface charge density and light-scattering of the Plectonema boryanum spheroplasts 硼球质体的表面电荷密度和光散射

Bioelectrochemistry and bioenergetics (Lausanne, Switzerland) Pub Date : 1999-02-01 DOI: 10.1016/S0302-4598(98)00217-7

Virjinia Doltchinkova

{"title":"Surface charge density and light-scattering of the Plectonema boryanum spheroplasts","authors":"Virjinia Doltchinkova","doi":"10.1016/S0302-4598(98)00217-7","DOIUrl":"10.1016/S0302-4598(98)00217-7","url":null,"abstract":"<div><p>The electrokinetic properties of spheroplasts from the cyanobacterium <em>Plectonema boryanum</em> were examined by particle microelectrophoresis technique. The electrophoretic mobility (EPM) of the particles was determined after incubation with CaCl<sub>2</sub> in dependence of iron content in culture media as follows: an iron sufficient medium (`control' variant), an iron-deficient medium (`Fe-starved' variant) and an excess of iron supply medium (`20×Fe' variant). Strong increase in EPM was observed with micromolar concentrations of divalent cations at `20×Fe' spheroplasts. This pattern of calcium efficiency was not accompanied with the cation influences on the aggregate ability of particles. The EPM of `control' spheroplasts strongly decreased with addition of calcium cations. The `Fe-starved' speroplasts were characterized with a slight reduction in EPM and a mild change in light-scattering properties of the particles. The data is the direct demonstration of the interaction between calcium cations and spheroplast surface, which could be proposed to play a role in the environmental cycling of iron.</p></div>","PeriodicalId":79804,"journal":{"name":"Bioelectrochemistry and bioenergetics (Lausanne, Switzerland)","volume":"48 1","pages":"Pages 237-241"},"PeriodicalIF":0.0,"publicationDate":"1999-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/S0302-4598(98)00217-7","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"21099375","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 1

Electric pulse-induced precipitation of biological macromolecules in electroporation 电穿孔中生物大分子的电脉冲诱导沉淀

Bioelectrochemistry and bioenergetics (Lausanne, Switzerland) Pub Date : 1999-02-01 DOI: 10.1016/S0302-4598(98)00206-2

Romualdas Stapulionis

引用次数: 31

Electron transfer between ferrocene-modified Au/octadecanethiol/lipid BLM electrode and redox couples in solution 二茂铁修饰金/十八烷硫醇/脂质BLM电极与溶液中氧化还原对之间的电子转移

Bioelectrochemistry and bioenergetics (Lausanne, Switzerland) Pub Date : 1999-02-01 DOI: 10.1016/S0302-4598(98)00202-5

Xiaoli Cui , Dianlu Jiang , Peng Diao , Junxin Li , Ruting Tong , Xinkui Wang

引用次数: 7

Thiohydrazone copper(II) complexes. The relationship between redox properties and superoxide dismutase mimetic activity 硫腙铜(II)配合物。氧化还原性质与超氧化物歧化酶模拟活性的关系

Bioelectrochemistry and bioenergetics (Lausanne, Switzerland) Pub Date : 1999-02-01 DOI: 10.1016/S0302-4598(98)00231-1

Zdena Ďuračková , Ma.Antonia Mendiola , Ma.Teresa Sevilla , Aladar Valent

{"title":"Thiohydrazone copper(II) complexes. The relationship between redox properties and superoxide dismutase mimetic activity","authors":"Zdena Ďuračková , Ma.Antonia Mendiola , Ma.Teresa Sevilla , Aladar Valent","doi":"10.1016/S0302-4598(98)00231-1","DOIUrl":"10.1016/S0302-4598(98)00231-1","url":null,"abstract":"<div><p>The redox behaviour of copper(II) complexes with the open chain ligand, benzilbisthiosemicarbazone, and the macrocyclic one [3,4,10,11-tetraphenyl-1,2,5,8,9,12,13-octaazacyclotetradeca-7,14-dithione-2,4,9,11-tetraene] has been explored by cyclic voltammetry. The half-wave potential values for the copper(II)/copper(I) redox couple and the spectral data obtained on dimethylsulfoxide (DMSO) solution agree with the superoxide dismutase (SOD)-mimetic activity of the complexes. The macrocyclic complexes show more positive reduction potential and more activity than the open chain derivatives. From our results it follows that the structure and conformation of ligand has influence on the redox potential of central atom in coordination compound. The changes in the coordination sphere are connected with the change of biological function of compounds represented by SOD-mimic activity. In addition, the <span><math><mtext>L</mtext><msup><mi></mi><mn>1</mn></msup><mtext>H</mtext><msub><mi></mi><mn>6</mn></msub></math></span> derivatives show quasireversible waves associated to Cu(II)/Cu(III) process.</p></div>","PeriodicalId":79804,"journal":{"name":"Bioelectrochemistry and bioenergetics (Lausanne, Switzerland)","volume":"48 1","pages":"Pages 109-116"},"PeriodicalIF":0.0,"publicationDate":"1999-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/S0302-4598(98)00231-1","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"21098289","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 32