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  • DSC  (52)
  • apoptosis  (52)
  • Springer  (104)
  • American Geophysical Union
  • Oxford University Press
  • 2010-2014
  • 1995-1999  (104)
  • 1985-1989
  • 2010
  • 1999  (104)
Collection
Keywords
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  • Springer  (104)
  • American Geophysical Union
  • Oxford University Press
  • Wiley-Blackwell  (1)
Years
  • 2010-2014
  • 1995-1999  (104)
  • 1985-1989
Year
  • 1
    Electronic Resource
    Electronic Resource
    Study on thermal transitions of toluene diisocyanate-based polyurethane elastomers with poly (tetramethylene oxide) as the soft segment by TSC/RMA, DSC and DMA thermal analyzers (1999)
    Springer
    Journal of polymer research 6 (1999), S. 67-78 
    Details
    ISSN: 1572-8935
    Keywords: TDI-based polyurethane elastomers ; Tg ; Tglobal transition ; DSC ; TSC/RMA ; DMA
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract Thermal transitions of TDI-based polyurethane elastomers with PTMO as the soft segment were characterized by the depolarization technique in TSC and by using with the thermal windowing technique on selected specimens in the RMA measurements. Results indicate that the broadened thermal transition in the glass transition region as observed in the DSC thermogram is related to the combined Tg transition and the Tglobal transition in the TSC spectrum. This Tglobal transition is associated with the macromolecular property as detected by tan δ in DMA measurement. The increase in the Tg with a high NCO content may be explained by the structural modification found on the urethanic chain with the additional linkage of the hard segment that affects the cooperative motion of the molecular chain. Data measured from DSC, TSC/RMA and DMA with simulated DEA and wide angle X-ray data are presented for the characterization of the polyurethanes. The RMA measurement leads to a compensation search on Tg transition and provides pertinent thermokinetic data that correlates the NCO content with changes in enthalpy and entropy on the relaxation behaviors in the Tg transition of polyurethane elastomers.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s10965-006-0073-4
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  • 2
    Electronic Resource
    Electronic Resource
    Apoptosis and p53 gene expression in male reproductive tissues of cadmium exposed rats (1999)
    Springer
    BioMetals 12 (1999), S. 131-139 
    Details
    ISSN: 1572-8773
    Keywords: cadmium ; apoptosis ; RT-PCR ; p53 gene expression ; testes ; rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Reverse transcription (RT) PCR technique was used to investigate the mechanism of apoptosis induced by Cd and the change of its related genes in testes and prostate of rats. Adult male rats were given a single (s.c.) injection of CdC l2 0, 2.5, 5.0, 10 μmol/kg. 48 h and 72 h after administration of Cd, animals were sacrificed. The results indicated that Cd can induce apoptosis in testes via p53-independent pathway. No apoptosis occurred in prostate in any of the Cd-exposed groups. There was a clearly negative relationship in testes between p53 gene expression and Cd exposure and this dose-response relationship was observed both at 48 h and 72 h. There was a very small increase of this gene expression in the dorsolateral lobe of the prostate in Cd exposed groups. The other apoptosis related gene, bcl-x, was not detectable in either control or Cd-exposed group in testes and dorsal prostate. Although the MT-I gene was expressed in testes or dorsal prostate both in control and exposed groups, no overexpression of MT-I gene was found after administration of Cd . The expression of MT-I in the ventral prostate was not detected in the control group, but a weak expression was found after Cd exposure. Since p53 is a tumo r suppressor gene which can inhibit tumorigenesis, the consequence of a Cd-induced decrease of p53 in testes may have a relation to the known risk of Cd tumorigenesis in this tissue.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1009273711068
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  • 3
    Electronic Resource
    Electronic Resource
    Thermal Analysis Studies on Isopropylnitrate (1999)
    Springer
    Journal of thermal analysis and calorimetry 55 (1999), S. 9-19 
    Details
    ISSN: 1572-8943
    Keywords: ARC ; DSC ; HFC ; kinetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Isopropylnitrate (IPN) is described as a detonable material used in propellants and explosives. While there is considerable information available on its sensitivity and compatibility with other materials, very little is known about its thermochemical properties. This paper will describe the results obtained from some DSC, heat flux calorimetry (HFC) and accelerating rate calorimetry (ARC) measurements. The ASTM DSC method using a hermetic aluminum pan having a lid with a laser-produced pin hole was used to determine the vapour pressure of IPN1. Results calculated from an Antoine equation are in substantial agreement with those determined from DSC measurements. From the latter measurements, the enthalpy of vaporization was determined to be 35.32±0.62 kJ mol−1. Attempts to determine vapour pressures above about 0.8 MPa resulted in significant decomposition of IPNg. The enthalpy change for decomposition in sealed glass systems was found to be -3.43±0.09 kJ g−1 and -3.85±0.03 kJ g−1, respectively from DSC and HFC measurements on IPN1 samples loaded in air. Slightly larger exotherms were observed for the HFC results in air than those in inert gas, suggesting some oxidation occurs. In contrast, no significant difference in the observed onset temperature of about 150°C was observed for both the HFC and ARC results. From DSC measurements, an Arrhenius activation energy for decomposition of 126±4 kJ mol−1 was found. These measurements were also conducted in sealed glass systems and decomposition appeared to proceed primarily from the liquid phase.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1010190829563
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  • 4
    Electronic Resource
    Electronic Resource
    Apparent Activation Energies of the Non-isothermal Degradation of Eva Copolymer (1999)
    Springer
    Journal of thermal analysis and calorimetry 55 (1999), S. 67-76 
    Details
    ISSN: 1572-8943
    Keywords: activation energy ; DSC ; ethylene-vinyl acetate copolymer ; TG ; TG/IR ; thermal degradation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract When ethylene-vinyl acetate copolymer, EVA, is heated, a two-stage thermal degradation occurs following its melting. The vinyl acetate content of the copolymer was determined to be 43.8% by using TA 2950 and TA 2050 thermogravimetric instruments. TG/FTIR was used to detect the evolved gas. Acetic acid and trans-1-R-4-R'-cyclohexane were the main products evolved from EVA in the first and second stage, respectively. The apparent activation energies were determined for both stages by differential methods.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1010175904064
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  • 5
    Electronic Resource
    Electronic Resource
    Crystallization Kinetics of Polypropylene-polyethylene-based Copolymers (1999)
    Springer
    Journal of thermal analysis and calorimetry 55 (1999), S. 57-65 
    Details
    ISSN: 1572-8943
    Keywords: artificial ageing ; DSC ; dynamic crystallization ; isoconversional method
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract A crystallization kinetics analysis of several polypropylene-polyethylene (PP-PE), PP-rich copolymers was made by means of differential scanning calorimetry. The crystallization was studied via calorimetric measurements at different cooling rates. Several additives were added to the base material. Some test samples were subjected to artificial ageing processes. A modified isoconversional method was used to describe the crystallization process under non-isothermal conditions. The value of the Avrami parameter was determined for primary and secondary crystallization.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1010123819994
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  • 6
    Electronic Resource
    Electronic Resource
    Kinetic Analysis of Thermogravimetric Data XXXII. DSC Study of Some [Co(Diox·H)2(amine)2]X and H[Co(Diox·H)2(N3)2] Type Complexes with Alicyclic α-dioximes (1999)
    Springer
    Journal of thermal analysis and calorimetry 55 (1999), S. 311-320 
    Details
    ISSN: 1572-8943
    Keywords: dioximine complexes of Co ; DSC ; kinetic compensation effect ; kinetic parameters of thermal decomposition
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract 14 mixed Co(III) dioximine chelates of the types [Co(Diox·H)2(amine)2]X (X = Br, I, NO3, ClO4) and H[Co(Diox·H)2(N3)2], respectively (Diox·H2-1,2-cyclohexane dione dioxime (nyoxime), 1,2-cycloheptane dione dioxime (heptoxime) 1,2-cyclooctane dione dioxime (octoxime) were obtained and their thermal decompositions were studied in an argon atmosphere. After the dehydration of the crystallohydrates, both types of complexes exhibit 3 decomposition stages. For the [Co(Diox·H)2(amine)2]X type complexes (X = Br, I) the first endothermal stage is the substitution of an amine molecule for the external sphere anion and this process is followed by two exothermal decomposition stages. With H[Co(Diox·H)2(N3)2] type complexes the first and third processes are relatively slow, but the second process is very fast, corresponding to a vertical portion of the TG curves. From the TG curves kinetic parameters were derived for 11 processes and the validity of a non-linear compensation law was observed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1010185517693
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  • 7
    Electronic Resource
    Electronic Resource
    Calorimetric Investigations of Some Phases in the System Sodium Fluoride - Aluminium Fluoride (1999)
    Springer
    Journal of thermal analysis and calorimetry 56 (1999), S. 51-57 
    Details
    ISSN: 1572-8943
    Keywords: DSC ; enthalpies ; NaAlF4 ; Na5Al3F14
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Beside the two well-known minerals cryolite, Na3AlF6, and chiolite, Na5Al3F14, the binary system NaF-AlF3 also contains a third compound, NaAlF4, sodium tetrafluoroaluminate. Solid NaAlF4 has been prepared from its vapour under controlled conditions. The stability of NaAlF4 has been investigated by differential scanning calorimetry. It is shown that the disproportionation of the compound: 5NaAlF4(s)=Na5Al3F14(s)+2AlF3(s) takes place at considerable rate between 700 and 900 K. The enthalpy of this reaction is calculated and found to be -66.9 kJ. Enthalpies of the two solid state transitions α-Na3AlF6 → β-Na3AlF6 and α-AlF3 → β-AlF3 have also been measured and new values are reported. The enthalpy of formation of chiolite, Na5Al3F14, at 900 K has been recalculated from enthalpy increment data obtained by drop calorimetry. A value of ΔH900 o = -7513.6±12.0 kJ mol-1 has been obtained. This value is in disagreement with the recommended value given in JANAF Thermochemical Tables given at 900 K ΔHf o = -7559.2 kJ mol-1.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1010175006354
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  • 8
    Electronic Resource
    Electronic Resource
    The Fe-Ni Distribution Between Pentlandite and Monosulfide Solid Solution Equalized at Low Temperature (1999)
    Springer
    Journal of thermal analysis and calorimetry 56 (1999), S. 925-929 
    Details
    ISSN: 1572-8943
    Keywords: DSC ; equilibrium ; Fe-Ni distribution ; monosulfide solid solution ; pentlandite
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Two mixtures of pentlandite and the monosulfide solid solution (mss) have been synthesized. The bulk compositions of the samples are Fe6Ni3S8 and Fe3Ni6S8. Differential scanning calorimetry detected exothermic process in the samples under heating. The process takes place in temperature range between phase transition in the mss (near 400 K) and 690 K and is governed by diffusion. X-ray powder diffraction has showed that equilibrium Fe-Ni distribution between pentlandite and the mss is achieved after short-time heating up to 670 K.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1010199332433
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  • 9
    Electronic Resource
    Electronic Resource
    Cure Kinetics of Amine Cured Tetrafunctional Epoxy Blends with Poly(Styrene-Co-Acrylonitrile) (1999)
    Springer
    Journal of thermal analysis and calorimetry 56 (1999), S. 1033-1040 
    Details
    ISSN: 1572-8943
    Keywords: cure kinetics ; DSC ; epoxy resin ; SAN ; thermoplastic blends
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Cure kinetics using a differential scanning calorimetry (DSC) technique were analyzed for a thermoplastic modified tetraglycidyl-4,4′-diaminodiphenylmethane (TGDDM) epoxy resin cured with diaminodiphenylsulphone (DDS), an aromatic diamine. The neat resin and its blends with the poly(styrene-co-acrylonitrile) (SAN) of various compositions were studied by applying a phenomenological model proposed by Kamal. Kinetic parameters were determined by fitting experimental data. This model gives a good description of cure kinetics up to the onset of vitrification. Diffusion control was incorporated to describe the cure in the latter stages of cure. The results showed that the addition of SAN did not alter the nature of the reaction, but the reaction rates and final conversions decreased when SAN contents increase, due to reduction of mobility of the reacting species.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1010128206026
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  • 10
    Electronic Resource
    Electronic Resource
    Thermal Analysis, Microcalorimetry and Combined Techniques for the Study of Pharmaceuticals (1999)
    Springer
    Journal of thermal analysis and calorimetry 56 (1999), S. 1285-1304 
    Details
    ISSN: 1572-8943
    Keywords: amorphous state ; combined techniques ; drug design ; drug product development ; drug substance ; drug technology ; DSC ; excipients ; failure investigations ; hydrates ; MDSC ; microcalorimetry ; pharmaceuticals ; polymorphism ; polymers ; preformulation ; process optimization ; purity ; quality control ; solvates ; stability ; sub-ambient DSC ; TG ; temperature resolved X-ray diffraction ; water interactions ; thermal microscopy ; water sorption-desorption
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Modern thermal analysis, microcalorimetry and new emerging combined techniques which deliver calorimetric, microscopic and spectroscopic data offer a powerful analytical battery for the study of pharmaceuticals. These techniques are very useful in all steps of development of new drug products as well as methods for quality control in production. The characterization of raw materials enables to understand the relationships between polymorphs, solvates and hydrates and to choose the proper development of new drug products with very small amount of material in a very short time. Information on stability, purity is valuable for new entities as well as for marketed drug substances from different suppliers. Excipients which vary from single organic or inorganic entity to complexes matrixes or polymers need to be characterized and properly controlled. The thermodynamic phase-diagrams are the basis of the studies of drug-excipients interactions. They are very useful for the development of new delivery systems. A great number of new formulations need proper knowledge of the behaviour of the glass transition temperature of the components. Semi-liquid systems, interactions in aqueous media are also successfully studied by these techniques.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1010194020563
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  • 11
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    Thermal Analysis, Microcalorimetry and Combined Techniques for the Study of the Polymorphic Behaviour of a Purine Derivative (1999)
    Springer
    Journal of thermal analysis and calorimetry 57 (1999), S. 61-73 
    Details
    ISSN: 1572-8943
    Keywords: amorphous ; combined techniques for polymorphism ; DSC ; MKS 492 ; polymorphism ; purine ; quantitative determination ofamorphous and polymorphs ; solvent mediated transitions ; temperature resolved X-ray diffraction ; TG ; thermodynamic relation between polymorphs ; xanthine
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The polymorphic behaviour of the purine derivative MKS 492 was studied with investigations of suspensions of selected samples in different solvents and of samples obtained by crystallizations. The samples were analyzed by DSC, TG and X-ray diffraction. Six different crystalline modifications called A, B, B’, C, D and E and an amorphous form were identified. Four pure crystalline modifications, A, B, C and D have been manufactured and characterized by DSC, X-ray, IR, solubilities, densities, hygroscopicity and dissolution measurements. The four forms A, C, D and E are monotrop to the form B. The form B is enantiotrop to the form B’, which revealed the highest melting point of all known polymorphs. This form B’ is only stable at high temperature. Temperature resolved X-ray diffraction was very helpful for proper interpretation of the thermal events. The melting peaks of the forms A and C and the endothermic peak corresponding to the enantiotropic transition B into B’ occur in a narrow range of temperature. The form B which is the most stable one at room temperature has been chosen for further development. Quantitative methods to determine the content of the forms A, C and D in samples of form B or to determine the content of form A, B and D in form C have been developed by using X-ray diffraction. Limits of detection are 1 or 2%. For the quantitative determination of the amorphous fraction, X-ray diffraction and microcalorimetry are compared. For high amounts of the amorphous fraction, the X-ray diffraction method is preferred because it is faster. Microcalorimetry is very attractive for levels below 10% amorphous content. The lowest limit of detection is obtained by microcalorimetry, about 1%.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1010145125531
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  • 12
    Electronic Resource
    Electronic Resource
    Comparison of Experimental Methods and Theoretical Calculations on Crystal Energies of ‘Isoenergetic’ Polymorphs of Cimetidine (1999)
    Springer
    Journal of thermal analysis and calorimetry 57 (1999), S. 7-22 
    Details
    ISSN: 1572-8943
    Keywords: crystal modifications ; DSC ; Gibbs free energy function ; molecular modelling ; solution calorimetry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The thermodynamic energy relationship between two crystal modifications of cimetidine was investigated and compared with differences in their processing properties with respect to transformation from one modification to the other. The crystal energies of the two modifications A and D were found to be almost identical and therefore the polymorphs are regarded as virtually isoenergetic crystals. This statement is based on DSC measurements of the melting points and of the enthalpies of fusion for the two crystal forms, which enable the calculation of the Gibbs free energy functions. Furthermore, the statement is supported by measurements of the enthalpies of solution in two different solvents. Both DSC and solution experiments reveal a slightly higher stability of the D modification with respect to the A form. In addition, tribomechanical treatment also indicates modification D to be the more stable one, as well as the higher density of the D form. No transformation during DSC at low heating rate was found which could be used in a stability consideration. As the explicit crystal structures of the two modifications are resolved, it was possible to calculate crystal energies theoretically as well. The theoretical results showed a remarkable difference in the crystal energies at zero degree Kelvin. Furthermore, they were just contradicting experimental findings by stating A being more stable than D. Possible reasons for this discrepancy and the feasibility of today's calculation methods with respect to prediction of stability properties are discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1010137505058
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  • 13
    Electronic Resource
    Electronic Resource
    Polymorphism of Acrylic and Methacrylic Acid Esters Containing Long Fluorocarbon Chains and Their Polymerizability (1999)
    Springer
    Journal of thermal analysis and calorimetry 57 (1999), S. 631-642 
    Details
    ISSN: 1572-8943
    Keywords: DSC ; fluorocarbon chain ; polymerizability ; polymorphic behaviors ; X-ray diffraction
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The molecular aggregation of acrylic and methacrylic acid esters containing long-fluorocarbon chains: 2-(perfluoroalkyl)ethyl acrylate (FFnEA) and 2-(perfluoroalkyl)ethyl methacrylate (FFnEMA) (F(CF2)nCH2CH2OCOC(X)=CH2, where X=H, CH3 and n=6, 8, 10) was investigated by differential scanning calorimetry (DSC) and temperature controlled X-ray powder diffraction measurement. These compounds exhibited some characteristic polymorphic behaviors depending on the length of fluorocarbon chain and the α-position methyl group. The solid-state polymerization by γ-ray irradiation was studied for these compounds in the various crystal forms. In the solid-state polymerization, highest polymerizability was observed in the crystal form that exists in the highest temperature region for each compound.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1010113420330
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  • 14
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    Study of Ethyl Cellulose—Benzoic Acid Interactions in Matrices for Controlled Drug Release by DSC (1999)
    Springer
    Journal of thermal analysis and calorimetry 58 (1999), S. 29-38 
    Details
    ISSN: 1572-8943
    Keywords: benzoicacid ; controlled release ; DSC ; ethyl cellulose ; FTIR
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The physical state of benzoic acid (BA) and its interaction with ethyl cellulose (EC) were examined in ethyl cellulose—benzoic acid matrices by Differential Scanning Calorimetry (DSC). The glass transition temperature (Tg) of EC of various matrices having BA in solid solution form (upto 27.7%) was reduced. The BA in matrices containing more than 38.9% drug exhibited distinct melting endotherms due to crystalline form. The peak temperatures of these endotherms were lowered and they broadened as the concentration was lowered. The solubility of BA increased at its melting point as compared to ambient temperature. The melting enthalpy of BA, when plotted as a function of its concentration yielded a straight line with intercept of 330 mg g−1 of matrix. This is the solubility of BA in EC at its melting temperature. Fourier Transform Infra Red Spectroscopy (FTIR) investigations confirmed that hydrogen bonding occurred between EC and BA through hydroxyl groups.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1010183301617
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  • 15
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    Combination of DSC and X-ray Diffraction in the Study of the Phase Behaviour of Lipids: Mini-review (1999)
    Springer
    Journal of thermal analysis and calorimetry 58 (1999), S. 363-368 
    Details
    ISSN: 1572-8943
    Keywords: DSC ; lipid ; phase behaviour ; synchrotron radiation ; X-ray diffraction
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The phase behaviour and phase stability of lipids are of importance in an understanding of the biological functions of cell membranes. Among a variety of physical techniques employed to study the phase behaviour and structural properties of polar lipids, differential scanning calorimetry and X-ray diffraction have proved to be successful and are the most frequently used methods. Applications involving a combination of the two techniques, particularly when synchrotron radiation is used as the light source of X-ray diffraction, are reviewed in this article.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1010103205120
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  • 16
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    Measurements of Heat of Zeolite Dehydration by Scanning Heating (1999)
    Springer
    Journal of thermal analysis and calorimetry 58 (1999), S. 653-662 
    Details
    ISSN: 1572-8943
    Keywords: dehydration ; DSC ; TG ; water ; zeolites
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract A procedure for measurement of the heat of zeolite dehydration by scanning heating has been designed. Simultaneous data on heat flow (DSC) and mass loss (TG) are required for evaluation. The heating rate depends on the experimental conditions (point-spread function, sample mass, crucible design, and calorimetric reproducibility). Dehydration measurements have three advantages as compared with the sorption procedure: i) one can investigate samples with irreversible dehydration; ii) no approximation model is needed for calculation of the partial molar heat of dehydration; and iii) the procedure is not labor-consuming. The procedure was tested on the natural zeolites heulandite, chabazite and mordenite. The results are close to those measured by the sorption procedure. The partial molar heat of dehydration was found to depend on the water content. It increases from 50 to 87 J mol−1 K−1 for heulandite, from 53 to 81 J mol−1 K−1 for chabazite, and from 51 to 71 J mol−1 K−1 for mordenite. The approximation of the heat of sorption by linear regression was found to be wrong. Detection of a ‘phase transitioN’ after this approximation has no meaning.
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    URL: http://dx.doi.org/10.1023/A:1010116930852
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  • 17
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    Transformation-Governed Heating Techniques in Thermal Analysis II. (1999)
    Springer
    Journal of thermal analysis and calorimetry 58 (1999), S. 725-739 
    Details
    ISSN: 1572-8943
    Keywords: DDC ; DSC ; DTA ; transformation-governed TA
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The described instrumental method makes it possible that the quasi-static heating technique, well applicable to thermogravimetric measurements, (see Part I of this paper) can be used in the case of DTA and DSC examinations, too. Based on the new type of curves the characteristic transformation temperatures, the whole course of the transformation in dependence of sample temperature, the extent of the enthalpy change caused by the transformation or by its partial processes can accurately be determined. The essentially greater accuracy of the measurements — in comparison to the conventional ones — is due to the quasi-static heating technique which ensures that the transformations should take place under quasi-equilibrium conditions.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1010181217648
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  • 18
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    Effects of Added Urea and Alkylureas on Gel to Liquid-Crystal Transitions in Doab Vesicles (1999)
    Springer
    Journal of thermal analysis and calorimetry 55 (1999), S. 29-35 
    Details
    ISSN: 1572-8943
    Keywords: alkylureas ; DOAB vesicles ; DSC ; gel-liquid transitions ; urea
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The gel to liquid-crystal transition for vesicles in aqueous solution formed by dimethyldi-n-octadecylammonium bromide (DOAB) occurs at 44.7°C. Moreover, the shapes of the scans recorded by a sensitive DSC microcalorimeter are very similar when the vesicular solutions are prepared starting with solid DOAB and comparable amounts of either solid urea or solid alkylureas. Therefore, the DOAB vesicles in aqueous solution accommodate this class of solutes without marked changes in the melting temperature and the enthalpy of the transition. The contrast with effects of added surfactants and simple organic solutes such as THF and ethanol is particularly significant.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1010159400429
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  • 19
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    Thermal and Spectroscopic Study of Dehydration of Lithium Formate Monohydrate Single-crystals (1999)
    Springer
    Journal of thermal analysis and calorimetry 55 (1999), S. 807-816 
    Details
    ISSN: 1572-8943
    Keywords: DSC ; hydrogen-bond ; IR ; lithium formate monohydrate ; Raman spectroscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Differential scanning calorimetry (DSC) and thermogravimetric analysis (TG) of lithium formate monohydrate (LiHCOO·H2O) were performed in the temperature range 300–700 K. The DSC/TG measurements show that the dehydration process to anhydrous lithium formate (LiHCOO) is complex and occurs in two stages. The data are correlated to the structure and to the arrangement of the molecules in the crystal, including the hydrogen-bonding. Infrared transmittance and Raman spectra of this crystal are reported and commented on.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1010125631748
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    Thermal Decomposition of Strontium and Barium Malonates (1999)
    Springer
    Journal of thermal analysis and calorimetry 55 (1999), S. 789-796 
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    ISSN: 1572-8943
    Keywords: alkaline earth malonates ; DSC ; DTA ; kinetic parameters ; TG ; thermal decomposition
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The thermal decomposition of strontium and barium malonates has been studied isothermally and non-isothermally employing simultaneous TG-DTG-DTA, DSC, XRD and IR spectroscopic techniques. DSC of these malonates has been recorded both in oxygen and nitrogen atmospheres. The decomposition is a single step process and the end product formed is carbonate. The energy of activation and frequency factor values for the decomposition of strontium malonate are 547 kJ mol−1 and 1041 s−1 respectively. The activation energy and frequency factor values for isothermal dehydration of barium malonate sester-hydrate are 57–111 kJ mol−1 and 107–1012 s−1 respectively and the corresponding values for decomposition from DSC are 499.5 kJ mol−1 and 1044 s−1 respectively. The higher thermal stability of strontium malonate as compared to that of barium salt is ascribed to its being anhydrous so that decomposition proceeds without restructuring. Their thermal stabilities have also been compared with that of respective oxalate salts.
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    URL: http://dx.doi.org/10.1023/A:1010169414001
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    From Precursors to Thin Films - Thermoanalytical Techniques in the Thin Film Technology (1999)
    Springer
    Journal of thermal analysis and calorimetry 56 (1999), S. 7-15 
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    ISSN: 1572-8943
    Keywords: ALE ; CVD ; DSC ; DTA ; EGA ; EL display ; solar cell ; sol-gel ; spray pyrolysis ; super-conductor ; TG ; thin films
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Processing thin films for advanced applications, for instance in electronics and optoelectronics, involves several steps starting from precursor synthesis and ending up with the devices. Especially when optimizing the first steps of this chain of processes, thermoanalytical techniques play an important role. The review will focus on the main chemical deposition methods (CVD, ALE, spray pyrolysis, sol-gel) giving selected examples of problem-solving by thermal analysis. The techniques discussed are TG, DTA/DSC, EGA and their combinations. High-temperature X-ray diffraction (HTXRD) is also a powerful tool for in situ studies of thin films. The examples are taken from solar cell, superconductor and flat panel electroluminescent display technologies.
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    URL: http://dx.doi.org/10.1023/A:1010154818649
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    α-β Phase Re-Transformation Kinetics in Nickel Sulphide (1999)
    Springer
    Journal of thermal analysis and calorimetry 56 (1999), S. 429-435 
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    ISSN: 1572-8943
    Keywords: DSC ; nickel sulphide ; TG ; toughened glass ; X-ray diffraction
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Nickel sulphide (NiS) was characterised using X-ray diffraction, thermal gravimetric analysis (TG) and differential scanning calorimetry (DSC). The 'as received' Millerite, stoichiometric NiS, observed to be slightly nickel deficient, was found to readily decompose in a nitrogen atmosphere at elevated temperatures (450°C max.) to the sulphur deficient Godlevskite, Ni7S6. DSC and X-ray measurements demonstrated that the high temperature form of the Godlevskite was readily stabilised at room temperature. The kinetics of the α-β re-transformation in Godlevskite were then investigated using DSC and were observed to be first order.
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    Thermochemistry of the Decomposition of Some Cobalt Compounds (1999)
    Springer
    Journal of thermal analysis and calorimetry 56 (1999), S. 547-552 
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    ISSN: 1572-8943
    Keywords: cobalt oxysalts ; DSC ; enthalpy of decomposition ; enthalpy of dehydration ; thermal decomposition
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Differential scanning calorimetry (DSC) was used to determine the molar enthalpies of dehydration and decomposition of CoC2O4·2H2O, Co(HCOO)2·2H2O and [Co(NH3)6]2(C2O4)3·4H2O. The first stage of dissociation of each compound is a single-step dehydration both in air and argon atmospheres. The next stages are decomposition processes influenced by experimental parameters. The enthalpies of dehydration and decomposition vary from compound to compound in each atmosphere. The obtained data have been related to the macromechanisms proposed for the thermal decomposition and the parallel-consecutive decomposition-oxidation processes.
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    URL: http://dx.doi.org/10.1023/A:1010156728374
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    Isothermal and Non-Isothermal Kinetics When Mechanistic Information Available (1999)
    Springer
    Journal of thermal analysis and calorimetry 56 (1999), S. 783-792 
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    ISSN: 1572-8943
    Keywords: complex process ; DSC ; isoconversional methods ; kinetics ; model-free kinetics ; peak maximum evolution methods ; simulations
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract In the case of a complex mechanism of two parallel independent reactions, peak maximum evolution methods and model-fitting methods give only a mean value of the kinetic parameters, while isoconversional methods are useful to describe the complexity of the mechanism. Isothermal and non-isothermal isoconversional methods can be used to elucidate the kinetics of the process. Nevertheless, isothermal isoconversional methods can be limited by restrictions on the temperature regions experimentally available because of duration times or detection limits.
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    Feasibility Study of Crude Oil Fields by Thermal Analysis Techniques (1999)
    Springer
    Journal of thermal analysis and calorimetry 56 (1999), S. 947-951 
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    ISSN: 1572-8943
    Keywords: combustion ; crude oil ; DSC ; TG/DTG
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract This paper investigates the minimum oil content necessary for self-sustained combustion, which is introduced as a criterion for the selection of suitable reservoirs for in-situ combustion processes. Differential scanning calorimetry was used to determine the heat values of oil-limestone mixtures. The minimum temperature required for the total consumption of the fuel was obtained by thermogravimetry (TG/DTG). The minimum amount of oil necessary to sustain combustion was calculated from these two parameters and compared with the oil content of the reservoir. Reservoirs with an oil content greater than or equal to this minimum value were considered feasible. It was seen that the fields examined are generally not suitable for in-situ combustion processes.
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    URL: http://dx.doi.org/10.1023/A:1010155617412
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    Isothermal Crystallisation of PCL Studied by Temperature Modulated Dynamic Mechanical and TMDSC Analysis (1999)
    Springer
    Journal of thermal analysis and calorimetry 56 (1999), S. 1155-1161 
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    ISSN: 1572-8943
    Keywords: crystallisation ; DMA ; DSC ; PCL ; polymer ; temperature modulation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Temperature modulated dynamic mechanical analysis (TMDMA) was performed in the same way as temperature modulated DSC (TMDSC) measurements. As in TMDSC TMDMA allows the investigation of reversible and non-reversible phenomena during crystallisation of polymers. The advantage of TMDMA compared to TMDSC is the high sensitivity for small and slow changes in crystallinity, e.g. during re-crystallisation. The combination of TMDMA and TMDSC yields new information about local processes at the surface of polymer crystallites. It is shown that during and after isothermal crystallisation the surface of the individual crystallites is in equilibrium with the surrounding melt.
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    The Influence of Annealing and Heavy Ion Irradiation of Multiple Melting and Crystallization in PBT Films (1999)
    Springer
    Journal of thermal analysis and calorimetry 56 (1999), S. 1141-1146 
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    ISSN: 1572-8943
    Keywords: crystallization ; DSC ; heavy ion irradiation ; melting ; PBT films ; poly(butyleneterephthalate) films
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The influence of heavy ion-irradiation (Ar 5.5 MeV amu-1, 5·1011 ion cm-2) on the melting and crystallization of two PBT films subjected to different modes of thermal treatment was investigated. Differences were observed between the processes occurring in both initial films, due to differences in crystalline phase content. The course of melting and crystallization in heavy ion-irradiated films during first heating, cooling and second heating differs from that in the initial films. The density data and DSC results indicate a decreased crystalline phase content in the PBT films after irradiation.
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    Thermal Behaviour of Some Terpenoids (1999)
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    Journal of thermal analysis and calorimetry 56 (1999), S. 1353-1357 
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    ISSN: 1572-8943
    Keywords: DSC ; terpenoids ; TG ; thermal behaviour
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The terpenoids acetyl sitosterol, lupeol, acetyl diosgenin and stigmasterol were studied. Comparison of the thermogravimetric curves and the activation energies of the terpenoids suggested the following sequence of thermal stability: acetyl sitosterol 〈 acetyl diosgenin 〈 lupeol 〈 stigmasterol. The DSC curves allowed determination of the melting points and the degrees of purity. Comparison of the TG and DSC curves revealed the presence of phase transitions without mass loss that were attributed to rearrangements in the terpenoid molecules.
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    Lipid-similar Thermal Transition of Polyethylene Glycol Alkyl Ether Detergents (1999)
    Springer
    Journal of thermal analysis and calorimetry 57 (1999), S. 371-375 
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    ISSN: 1572-8943
    Keywords: C14E8 ; detergent ; DSC ; polyethylene glycol tetradecyl ether ; thermal transition
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract A narrow, reversible endothermic main transition is found in the aqueous micellar phase of octaethylene glycol tetradecyl ether (C14E8) by DSC, characterized by a transition temperature of 41°C and a ΔH value of 0.5 kcal mol−1, which is not observed by light scattering. This transition is assigned to a cooperative conformational rearrangement of the assembled amphiphilic detergent molecules and not to a micelle aggregation process. It is suggested that the detergent’s polar head group is primarily involved in this rearrangement.
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    On the Oximine Complexes of Transition Metals: Part 110: Spectroscopic and DSC study on some [Fe(Diox·H)2L2] and [Fe(Diox)3(BOR)2] type chelates and clathrochelates (1999)
    Springer
    Journal of thermal analysis and calorimetry 57 (1999), S. 433-445 
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    ISSN: 1572-8943
    Keywords: DSC ; iron(II)-oxime complexes ; kinetic parameters ; Mössbauer spectroscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract A number of 15 [Fe(Diox#x00B7;H)2L2] type chelates and [Fe(Diox)3(BOR)2] clathrochelates (Diox#x00B7;H2 — dimethylglyoxime, glyoxime, propoxime, nyoxime, furyl-dioxime; L-pyridine, alkyl-pyridine derivatives, diethyl-phenyl-phosphine, diethyl-p-tolyl-phosphine) were obtained and characterized by means of far and middle FTIR and Mössbauer spectroscopic methods. Some structural problems were discussed on the basis of the optical data. The DSC measurements show the higher thermal stability of the clathrochelates without O—H⋯O intramolecular hydrogen bonds (with asymmetric octahedral structure), as compared to the [Fe(Diox#x00B7;H)2L2] trans, symmetric chelates containing O—H⋯O bonds. The kinetic parameters of the thermal decomposition of the complexes have been derived using the nomogram method.
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    Decoupled Molecular Dynamics of Glass-forming Liquids Confined in Nano-meter Pores (1999)
    Springer
    Journal of thermal analysis and calorimetry 57 (1999), S. 745-752 
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    ISSN: 1572-8943
    Keywords: confinement effects ; DSC ; dynamic light scattering ; finite-size effects ; glass transition ; o-terphenyl
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Calorimetry is the method first used by Jackson and McKenna to study the effect of finite-size on the molecular dynamics of glass-formers confined in nano-meter scale pores. It was found that the glass transition is shifted to lower temperature as pore size decreases. Since then, other spectroscopic techniques have corroborated this finding and given more information on the molecular dynamics. These results are used to compare with the predictions of several theories of glass transition, and in particular the coupling model of the author.
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    Identification of Polyethylene by Differential Scanning Calorimetry: Application to forensic science (1999)
    Springer
    Journal of thermal analysis and calorimetry 57 (1999), S. 847-851 
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    ISSN: 1572-8943
    Keywords: DSC ; linear low-density polyethylene(LLDPE) ; low density polyethylene (LDPE) ; polymer blend ; thermal properties
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract A forensic sample consisting of melt-recrystallized polymers that was recovered from the scene of a fire in a factory was identified by differential scanning calorimetry. The factory commonly used two kinds of film sheets, A and B, made by different manufacturers. It was necessary to decide whether the forensic sample related to material A or B. The forensic sample and reference samples of materials A and B were subjected to infrared spectroscopy and pyrolysis gas chromatograph mass spectrometry measurements, which revealed their polyethylene nature. The thermal behaviour of the samples was examined by differential scanning calorimetry (DSC) and they were found to be blends of two kinds of polyethylenes, low-density polyethylene and linear low-density polyethylene. The samples could be identified and distinguished from each other via the DSC measurements.
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    Estimation of the Critical Temperature of Thermal Explosion for the Highly Nitrated Nitrocellulose Using Non-isothermal DSC (1999)
    Springer
    Journal of thermal analysis and calorimetry 58 (1999), S. 369-373 
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    ISSN: 1572-8943
    Keywords: critical temperature ; DSC ; HNNC ; non-isothermal
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Two methods for estimating the critical temperature (Tb) of thermal explosion for the highly nitrated nitrocellulose (HNNC) are derived from the Semenov's thermal explosion theory and two non-isothermal kinetic equations, dα/dt=Af(α)e−E/RT and dα/dt=Af(α)[1+E/(RT)(1–To/T)]e−E/RT, using reasonable hypotheses. We can easily obtain the values of the thermal decomposition activation energy (E), the onset temperature (Te) and the initial temperature (To) at which DSC curve deviates from the baseline of the non-isothermal DSC curve of HNNC, and then calculate the critical temperature (Tb) of thermal explosion by the two derived formulae. The results obtained with the two methods for HNNC are in agreement to each other.
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    Enthalpic Relaxation of 25Na2O·xTiO2·(75-x)SiO2 Glasses (1999)
    Springer
    Journal of thermal analysis and calorimetry 55 (1999), S. 155-164 
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    ISSN: 1572-8943
    Keywords: DSC ; glass ; relaxation ; structure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The enthalpic relaxation of the title glasses, studied by differential scanning calorimetry, is well described by a mathematical model based on the stretched exponential relaxation function with the relaxation time proportional to the actual viscosity. The dependence of viscosity on temperature and the fictive temperature was expressed by Mazurin's approximation. The relaxation parameters obtained correlated significantly with the glass composition, indicating the changes in the structural of the TiO2 role near a TiO2 content of 3–4 mol%.
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    Thermal Studies of Nickel(II) Squarate Complexes of Triamines in the Solid State (1999)
    Springer
    Journal of thermal analysis and calorimetry 55 (1999), S. 165-172 
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    ISSN: 1572-8943
    Keywords: DSC ; nickel(II) squarate ; phase transition ; TG-DTA ; triamine
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract [NiL2]C4O4·nH2O [where n=2 when L=diethylenetriamine(dien) and N-(3-aminopropyl)-1,3-propanediamine (dpt); n=3 when L=N-(2-aminoethyl)-1,3-propanediamine (aepn); n=0 when L=N2-methyldiethylenetriamine (medien)] and Ni(tmdien)C4O4·2H2O (where tmdien=1,4,7 trimethyl-diethylenetriamine) have been synthesised and investigated thermally in the solid state. Ni(dpt)C4O4·H2O has also been synthesised pyrolytically in the solid state from the corresponding bis complex. All the complexes possess octahedral geometry. The squarate anion takes part in coordination only in monotriamine species. [Ni(medien)2]C4O4 upon heating undergoes phase transition (270–285°C; ΔH=4.9 kJ mol−1) accompanied by colour change pink to grey. Thermal stability decreases with increase in chain length of the triamines.
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    Effects of Pretreatments on the Structure of Palladium-Containing Amorphous Alloys Followed by DSC (1999)
    Springer
    Journal of thermal analysis and calorimetry 56 (1999), S. 305-310 
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    ISSN: 1572-8943
    Keywords: amorphous palladium alloys ; DSC ; hydrogenation ; mechanical alloying ; phenylacetylene ; structural characterization ; X-ray diffractometry ; X-ray photoelectron spectroscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Amorphous PdZr, PdCuZr and PdCuSi alloy ribbons and powders are characterized by DSC, XRD and XPS in the as-received state and after treatments with oxygen, hydrogen or dilute hydrogen fluoride solution. Zr-containing alloys are shown to undergo substantial structural changes resulting in palladium enrichment on their surface, whereas no apparent changes in the bulk structure are found for PdCuSi. Catalytic activity and selectivity of the pretreated samples were tested in the hydrogenation of phenylacetylene.
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    Effect of Nucleotides on Thermal Transitions of Myosin (1999)
    Springer
    Journal of thermal analysis and calorimetry 56 (1999), S. 1203-1209 
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    ISSN: 1572-8943
    Keywords: conformation of myosin ; DSC ; EPR ; spin labelling
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The internal dynamics and the thermal stability of myosin in rabbit psoas muscle fibres in different intermediate states of the ATP hydrolysis cycle were studied by differential scanning calorimetry (DSC) and electron paramagnetic resonance (EPR) spectroscopy. Three overlapping endotherms were detected in rigor, in strongly binding and weakly binding state of myosin to actin. The transition at 58.4°C can be assigned to the nucleotide-binding domain. The transition at highest temperature represents the unfolding of the actin and the contributions arising from the actin-myosin interaction. The transition of 54°C reflects the interaction between the subunits of myosin. Nucleotide binding induced shifts of the melting temperatures and produced variations in the calorimetric enthalpy changes. The changes of the EPR parameters indicated local rearrangements of the internal structure in myosin heads.
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    Application of Thermogravimetry in the Quality Control of Chloramphenicol Tablets (1999)
    Springer
    Journal of thermal analysis and calorimetry 56 (1999), S. 1323-1327 
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    ISSN: 1572-8943
    Keywords: chloramphenicol ; DSC ; quality control ; TG
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The stability and thermal behaviour of chloramphenicol and various of its mixtures were investigated. The thermogravimetric and stability constant results showed that the chloramphenicol base is thermally more stable than the tablet in the studied formulation. The reduction in stability was attributed to the presence of starch in the formulation. The thermal decompositions of the chloramphenicol base and the tablet obey first-order kinetics.
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    Transient DSC, a Novel and Rapid Method for Assessing Pharmaceutical Powder Compacts (1999)
    Springer
    Journal of thermal analysis and calorimetry 56 (1999), S. 1311-1316 
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    ISSN: 1572-8943
    Keywords: alumina ; aluminum oxide ; compact ; DSC ; particles ; pentaerythritol tetraacetate ; pharmaceuticals ; powder ; thermal resistance ; transient state
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The previously described method involving the use of transient DSC was applied to pharmaceutical powder compacts and to ceramic powder compacts. The samples were prepared by compressing powders of pentaerythritol tetraacetate and two kinds of alumina powder (differing in particle size distribution) up to a pressure of 20 MPa by using a jig. For pentaerythritol tetraacetate, a linear relationship was obtained between the parameter obtained by DSC and the compaction pressure.
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    Simulation of the Glass Transition (1999)
    Springer
    Journal of thermal analysis and calorimetry 56 (1999), S. 1005-1010 
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    ISSN: 1572-8943
    Keywords: DSC ; enthalpic relaxation ; glass transition ; physical ageing
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Enthalpic relaxation has been used to model the development of the glass transition in polymers, using kinetic parameters determined separately. For this purpose the Kohlrausch-Williams-Watt stretched exponential function, relating the extent of relaxation, Φ(t), to time t and an average relaxation time, τa, i.e. $$1 - \Phi \left( t \right) = \exp \left( { - t/ta} \right)^{\beta }$$ where β is inversely related to the breadth of the relaxation spectrum, has been adopted. The relaxation time dependence on temperature was taken to follow the modified Arrhenius relationship, $$\tau _a = A\exp \left[ {\frac{{X\Delta H}}{{RT}} + \frac{{\left( {1 - X} \right)\Delta H}}{{RT'}}} \right]$$ where T is the storage and T′ the fictive temperature, X is the structure factor and ΔH the activation enthalpy. Both have been found to describe the process of enthalpic relaxation in polymer glasses and a direct comparison has been made with the change in specific heat observed with different cooling rates in DSC experiments. The effect of variables, such as activation enthalpies, pre-exponential factors, and the non-linear factors such as X and β on the observed Tgs and the temperature range over which the transition occurred have been determined.
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    Differential Scanning Calorimetric Investigations on Pyloric Caeca During Ripening of Salted Herring Products (1999)
    Springer
    Journal of thermal analysis and calorimetry 57 (1999), S. 283-291 
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    ISSN: 1572-8943
    Keywords: DSC ; fish ; general proteolytic activity ; pyloric caeca ; ripening ; salted herring product
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The thermoanalytical behaviour of pyloric caeca during salting and ripening was investigated using a Perkin Elmer DSC 7. Not only the thermal stability of the muscle proteins was influenced by salting but also that of pyloric caeca. It was recognised that the salting itself leads to a remarkable increase of the transition temperature compared with raw herring. An influence of the salt:fish ratio could be observed. The higher the salt content the higher the increase of the denaturation temperature. During ripening the transition temperature remained on a high level or showed only a slight decrease during the investigation period. The dependency from the salt content remained evident. The increase of the transition temperature was accompanied by a decrease of the transition enthalpy. The increase of thermal stability is connected with a decrease of the general proteolytic activity in pyloric caeca. Possibly, the enzymes are diffusing from the pyloric caeca into the muscle and cause there an increase of enzymatic activity observable in North Sea herring accompanied by a decrease of activity in pyloric caeca itself. Simultaneous the thermal stability of pyloric caeca is lowered. The reason for the differences in ripening could be seen in some enzyme-inhibiting factors unknown until now.
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    Thermal Denaturation of Bacterial Cells Examined by Differential Scanning Calorimetry (1999)
    Springer
    Journal of thermal analysis and calorimetry 57 (1999), S. 409-414 
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    ISSN: 1572-8943
    Keywords: DSC ; thermal denaturation ; vegetative bacteria
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Thermal stability of vegetative cells of Listeria monocytogenes, Escherichia coli and Lactobacillus plantarum was studied by counting viable fractions and determining DSC curves of their suspensions. DSC curves in the 5–99°C range showed a series of endothermic transitions between 50 and 60°C, where the heat destruction of cells occurred. Heat denaturation of DNA required a higher temperature than cell killing. Thermal death was strongly influenced by the pH, composition and NaCl content of the suspending buffer. A mathematical model developed by us enabled comparison of DSC peak temperatures and temperatures required for loss of viability.
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    Thermal Properties of Standard and Reference Humic Substances by Differential Scanning Calorimetry (1999)
    Springer
    Journal of thermal analysis and calorimetry 57 (1999), S. 517-526 
    Details
    ISSN: 1572-8943
    Keywords: DSC ; humic substances ; thermal properties
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Differential Scanning Calorimetry combined with Fourier transform infrared spectroscopy, was applied to the study of a number of fulvic and humic acids extracted from soils, peat, river and seawater. The thermal patterns obtained were related to the nature and origin of samples. The low-temperature endotherms were attributed to dehydration and loss of peripheral polysaccharide chains. The endotherm at 250°C observed for soil FA was ascribed to partial decarboxylation of more labile surface COOH groups, whereas the high-temperature exotherms at about 500°C were related to the degree of polycondensation of the aromatic network of the humic molecules.
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    Thermal Characterization of Polyurethane Acrylate Resins (1999)
    Springer
    Journal of thermal analysis and calorimetry 58 (1999), S. 13-18 
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    ISSN: 1572-8943
    Keywords: DSC ; enthalpic relaxation ; polyurethane ; TSDC
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Polyurethane acrylate resins cured by two different ways, a thermal way and a photochemical way, are investigated by means of differential scanning calorimetry (DSC) and thermally stimulated depolarization currents (TSDC). Even if both curing methods lead to the same material from a chemical point of view, we show that important differences exist between the thermocured resin and the photocured resin in terms of molecular relaxation behaviour.
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    Thermal and Mechanical Properties of Polyethylenes Synthesized with Metallocene Catalysts (1999)
    Springer
    Journal of thermal analysis and calorimetry 58 (1999), S. 559-568 
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    ISSN: 1572-8943
    Keywords: DMTA ; DSC ; mechanical properties ; metallocene catalysts ; polyethylene
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract A series of high density polyethylenes (HDPE) were synthesized via homogeneous polymerization with metallocene catalyst in two different reactors (glass and stainless steel). The thermal and mechanical properties of the polyethylenes, synthesized with two types of reactor and different reaction parameters, are discussed.
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    Regulation of cardiomyocyte apoptosis in ischemic reperfused mouse heart by glutathione peroxidase (1999)
    Springer
    Molecular and cellular biochemistry 196 (1999), S. 13-21 
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    ISSN: 1573-4919
    Keywords: apoptosis ; DNA fragmentation ; GSHPx-1 knockout mice ; GSHPx-1 transgenic mice ; ischemia/repurfusion
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Abstract Apoptosis, a genetically controlled programmed cell death, has been found to play a role in ischemic reperfusion injury in several animal species including rats and rabbits. To examine whether this is also true for other animals, an isolated perfused mouse heart was subjected to 30 min of ischemia followed by 2 h of reperfusion. Experiments were terminated before ischemia (baseline), after ischemia, and at 30, 60, 90 and 120 min of reperfusion. At the end of each experiment, hearts were processed for the evaluation of apoptosis and DNA laddering. The in situ end labeling (ISEL) technique was used to detect apoptotic cardiomyocyte nuclei while DNA laddering was evaluated by subjecting the DNA obtained from the cardiomyocytes to 1.8% agarose gel electrophoresis followed by photographing under UV illumination. The results of our study revealed that apoptotic cells appear only after 60 min of reperfusion as demonstrated by the intense fluorescence of the immunostained genomic DNA when observed under fluorescence microscopy. None of the ischemic hearts showed any evidence of apoptosis. These results were corroborated with the findings of DNA fragmentation showing increased ladders of DNA bands in the same reperfused hearts representing integer multiples of the internucleosomal DNA length (about 180 bp). Since our previous studies showed a role of glutathione peroxidase (GSHPx) in apoptotic cell death, we performed identical experiments using isolated hearts from GSHPx-l knockout mice and transgenic mice overexpressing GSHPx-l. GSHPx-l knockout mice showed evidence of apoptotic cell death even after 30 min of reperfusion. Significant number of apoptotic cells were found in the cardiomyocytes as compared to non-transgenic control animals. To the contrary, very few apoptotic cells were found in the hearts of the transgenic mice overexpressing GSHPx-l. Hearts of GSHPx-l knockout mice were more susceptible to ischemia/reperfusion injury while transgenic mice overexpressing GSHPx- 1 were less susceptible to ischemia reperfusion injury compared to non-transgenic control animals. The results of this study clearly demonstrate a role of GSHPx in ischemia/reperfusion-induced apoptosis in mouse heart.
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    Human DU145 prostate cancer cells overexpressing mitogen-activated protein kinase phosphatase-1 are resistant to Fas ligand-induced mitochondrial perturbations and cellular apoptosis (1999)
    Springer
    Molecular and cellular biochemistry 199 (1999), S. 169-178 
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    ISSN: 1573-4919
    Keywords: MKP-1 ; Fas ligand ; Fas ; apoptosis ; prostate cancer
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Abstract Recent studies have suggested that MAP kinase phosphatase 1 (MKP-1) is overexpressed in prostate cancer. To evaluate the role of MKP-1 in regulating cell death and tumor growth in prostate cancer, MKP-1 was conditionally overexpressed in the human prostate cancer cell line DU145. Overexpression of MKP-1 in DU145 cells blocked activation of stress-activated protein kinase (SAPK/JNK). MKP-1 overexpression in DU-145 cells was also found to inhibit Fas ligand (FasL)-induced apoptosis, as well as block the activation of caspases by Fas engagement. In addition, MKP-1 blocked the activation of apoptosis by transfected MEKK-1 and ASK-1, presumably through its inhibition of the SAPK/JNK family of enzymes. MKP-1 blocked the ability of FasL to induce loss of mitochondrial transmembrane potential (Δγm), suggesting that MKP-1 acts upstream of mitochondrial pro-apoptotic events induced by FasL and that the SAPK/JNK pathway may form the signaling link between Fas receptor and mitochondrial dysfunction. Thus, MKP-1 overexpression in prostate cancer may play a role in promoting prostate carcinogenesis by inhibiting FasL-induced cell death.
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    URL: http://dx.doi.org/10.1023/A:1006980326855
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    Poly(ADP-ribosylation) and apoptosis (1999)
    Springer
    Molecular and cellular biochemistry 199 (1999), S. 125-137 
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    ISSN: 1573-4919
    Keywords: apoptosis ; ADP-ribosylation ; caspases ; PARP ; PARG
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Abstract Poly(ADP-ribosylation) is a post-translational modification playing a relevant role in DNA damage recovery, DNA replication and viral integration. Several reports also suggest a modulation of this process during cell death by apoptosis. The aim of this review is to discuss the possible involvement of poly(ADP-ribosylation) during apoptosis, by dealing with general considerations on apoptosis, and further examining the correlation between NAD consumption and cell death, the regulation of poly(ADP-ribose) metabolism in apoptotic cells, the effect of poly(ADP-ribose) polymerase inhibition on cell death occurrence and the use of enzyme cleavage as a marker of apoptosis. Finally, the future prospects of the research in this area will be addressed.
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    A dual approach in the study of poly (ADP-ribose) polymerase: In vitro random mutagenesis and generation of deficient mice (1999)
    Springer
    Molecular and cellular biochemistry 193 (1999), S. 53-60 
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    ISSN: 1573-4919
    Keywords: DNA binding protein ; NAD metabolism ; cellular response to DNA damage ; γ-rays ; alkylating agents ; genomic instability ; apoptosis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Abstract A dual approach to the study of poly (ADP-ribose)polymerase (PARP) in terms of its structure and function has been developed in our laboratory. Random mutagenesis of the DNA binding domain and catalytic domain of the human PARP, has allowed us to identify residues that are crucial for its enzymatic activity. In parallel PARP knock-out mice were generated by inactivation of both alleles by gene targeting. We showed that: (i) they are exquisitely sensitive to γ-irradiation, (ii) they died rapidly from acute radiation toxicity to the small intestine, (iii) they displayed a high genomic instability to γ-irradiation and MNU injection and, (iv) bone marrow cells rapidly underwent apoptosis following MNU treatment, demonstrating that PARP is a survival factor playing an essential and positive role during DNA damage recovery and survival.
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    Involvement of PARP and poly(ADP-ribosyl)ation in the early stages of apoptosis and DNA replication (1999)
    Springer
    Molecular and cellular biochemistry 193 (1999), S. 137-148 
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    ISSN: 1573-4919
    Keywords: PARP ; poly(ADP-ribosyl)ation ; apoptosis ; DNA replication
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Abstract We have focused on the roles of PARP and poly(ADP-ribosyl)ation early in apoptosis, as well as during the early stages of differentiation-linked DNA replication. In both nuclear processes, a transient burst of PAR synthesis and PARP expression occurs early, prior to internucleosomal DNA cleavage before commitment to apoptosis as well as at the round of DNA replication prior to the onset of terminal differentiation. In intact human osteosarcoma cells undergoing spontaneous apoptosis, both PARP and PAR decreased after this early peak, concomitant with the inactivation and cleavage of PARP by caspase-3 and the onset of substantial DNA and nuclear fragmentation. Whereas 3T3-L1, osteosarcoma cells, and immortalized PARP +/+ fibroblasts exhibited this early burst of PAR synthesis during Fas-mediated apoptosis, neither PARP-depleted 3T3-L1 PARP-antisense cells nor PARP -/- fibroblasts showed this response. Consequently, whereas control cells progressed into apoptosis, as indicated by induction of caspase-3-like PARP-cleavage activity, PARP-antisense cells and PARP -/- fibroblasts did not, indicating a requirement for PARP and poly(ADP-ribosyl)ation of nuclear proteins at an early reversible stage of apoptosis. In parallel experiments, a transient increase in PARP expression and activity were also noted in 3T3-L1 preadipocytes 24 h after induction of differentiation, a stage at which ~95% of the cells were in S-phase, but not in PARP-depleted antisense cells, which were consequently unable to complete the round of DNA replication required for differentiation. PARP, a component of the multiprotein DNA replication complex (MRC) that catalyzes viral DNA replication in vitro, poly(ADP-ribosyl)ates 15 of ~40 MRC proteins, including DNA pol α, DNA topo I, and PCNA. Depletion of endogenous PARP by antisense RNA expression in 3T3-L1 cells results in MRCs devoid of any DNA pol α and DNA pol δ activities. Surprisingly, there was no new expression of PCNA and DNA pol α, as well as the transcription factor E2F-1 in PARP-antisense cells during entry into S-phase, suggesting that PARP may play a role in the expression of these proteins, perhaps by interacting with a site in the promoters for these genes.
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    Bcl-2, survivin and variant CD44 v7-v10 are downregulated and p53 is upregulated in breast cancer cells by progesterone: Inhibition of cell growth and induction of apoptosis (1999)
    Springer
    Molecular and cellular biochemistry 202 (1999), S. 53-61 
    Details
    ISSN: 1573-4919
    Keywords: breast cancer cells ; anti-apoptotic genes ; apoptosis ; progesterone
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Abstract Progesterone inhibits the proliferation of normal breast epithelial cells in vivo, as well as breast cancer cells in vitro. But the biologic mechanism of this inhibition remains to be determined. We explored the possibility that an antiproliferative activity of progesterone in breast cancer cell lines is due to its ability to induce apoptosis. Since p53, bcl-2 and survivin genetically control the apoptotic process, we investigated whether or not these genes could be involved in the progesterone-induced apoptosis. We found a maximal 90% inhibition of cell proliferation with T47-D breast cancer cells after exposure to 10 μM progesterone for 72 h. Control progesterone receptor negative MDA-231 cancer cells were unresponsive to 10 μM progesterone. The earliest sign of apoptosis is translocation of phosphatidylserine from the inner to the outer leaflet of the plasma membrane and can be monitored by the calcium-dependent binding of annexin V in conjunction with flow cytometry. After 24 h of exposure to 10 μM progesterone, cytofluorometric analysis of T47-D breast cancer cells indicated 43% were annexin V-positive and had undergone apoptosis and no cells showed signs of cellular necrosis (propidium iodide negative). After 72 h of exposure to 10 μM progesterone, 48% of the cells had undergone apoptosis and 40% were annexin V positive/propidium iodide positive indicating signs of necrosis. Control untreated cancer cells did not undergo apoptosis. Evidence proving apoptosis was also demonstrated by fragmentation of nuclear DNA into multiples of oligonucleosomal fragments. After 24 h of exposure of T47-D cells to either 1 or 10 μM progesterone, we observed a marked down-regulation of protooncogene bcl-2 protein and mRNA levels. mRNA levels of survivin and the metastatic variant CD44 v7-v10 were also downregulated. Progesterone increased p53 mRNA levels. These results demonstrate that progesterone at relative high physiological concentrations, but comparable to those seen in plasma during the third trimester of human pregnancy, exhibited a strong antiproliferative effect on breast cancer cells and induced apoptosis.
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    URL: http://dx.doi.org/10.1023/A:1007081021483
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    Role of nitric oxide in the induction of apoptosis by smokeless tobacco extract (1999)
    Springer
    Molecular and cellular biochemistry 200 (1999), S. 51-57 
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    ISSN: 1573-4919
    Keywords: smokeless tobacco ; apoptosis ; nitric oxide
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Abstract Smokeless tobacco usage is, a growing public health concern in the United States. Lesions of the oral cavity have been clearly linked to smokeless tobacco use. The objective of this study was to determine the biochemical effects of smokeless tobacco extract (STE) exposure upon hamster cheek pouch cell (HCPC-1) cultures. HCPC-1 cells were exposed to a 5 -fold dose-range of STE (0.5, 1.0 and 2.5%) over a time-course of 24-96 h. Following each exposure we measured various biochemical parameters of cell proliferation and cell death. Cell viability, cell cycle progression and S-phase DNA synthesis were measured as markers of cell proliferation. We measured lactate dehydrogenase leakage as a marker of cell membrane damage and cell death due to necrosis. No significant alterations were observed in cell cycle progression and cell proliferation as a result of exposure to STE. LDH measured colorimetrically indicated no significant effect with the lower doses (0.5, 1.0 and 2.5% STE). Apoptosis measured as the A0 peak and by the TUNEL procedure revealed that STE caused significant rates of apoptosis. Maximal apoptosis was noted between 48-96 h. In order to probe the mechanism further we measured the levels of nitrites as an indicator of nitric oxide (NO) in the media. NO levels were significantly elevated at the doses that caused an induction of apoptosis. The results from this study indicate that STE causes a dose-dependent induction of apoptosis and that this is mediated by nitric oxide.
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    Clostridial toxins: Molecular probes of Rho-dependent signaling and apoptosis (1999)
    Springer
    Molecular and cellular biochemistry 193 (1999), S. 37-42 
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    ISSN: 1573-4919
    Keywords: Rho ; GTPase ; toxins ; Clostridium ; signal transduction ; apoptosis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Abstract The Rho family small GTPases are members of the Ras superfamily of small GTPases. Rho proteins were first determined to act as key regulators of many types of actin cytoskeletal-dependent cellular functions. Recent work by several investigators indicates that Rho GTPases are also critical modulators of several important intracellular and nuclear signal transduction pathways. Certain clostridial toxins and exoenzymes covalently modify, and thereby inactivate, specific types of Rho family GTPases. As such, these microbial enzymes have proven invaluable in helping to identify structural and functional attributes of Rho GTPases.
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    Functional analysis of poly(ADP-ribose) polymerase in Drosophila melanogaster (1999)
    Springer
    Molecular and cellular biochemistry 193 (1999), S. 103-108 
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    ISSN: 1573-4919
    Keywords: Poly(ADP-ribose) polymerase ; Drosophila melanogaster ; alternative splicing ; apoptosis ; DNA repair ; development
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Abstract Poly(ADP-ribose) polymerase (PARP) is conserved in eukaryotes. To analyze the function of PARP, we isolated and characterized the gene for PARP in Drosophila melanogaster. The PARP gene consisted of six translatable exons and spanned more than 50 kb. The DNA binding domain is encoded by exons 1-4. Although the consensus cleavage site of CED-3 like protease during apoptosis is conserved from human to Xenopus laevis PARPs, it is neither conserved in the corresponding region of Drosophila nor Sarcophaga peregrina. There are two cDNAs species in Drosophila. One cDNA could encode the full length PARP protein (PARP I), while the other is a truncated cDNA which could encode a partial-length PARP protein (PARP II), which lacks the automodification domain and is possibly produced by alternative splicing. The expression of these two forms of PARP in E. coli demonstrated that while PARP II has the catalytic NAD-binding domain and DNA-binding domain it is enzymatically inactive. On the other hand PARP I is active. A deletion mutant of PARP gene could grow to the end of embryogenesis but did not grow to the adult fly. These results suggest that the PARP gene plays an important function during the development of Drosophila.
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    Newly discovered anti-inflammatory properties of the benzamides and nicotinamides (1999)
    Springer
    Molecular and cellular biochemistry 193 (1999), S. 119-125 
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    ISSN: 1573-4919
    Keywords: benzamides ; nicotinamides ; apoptosis ; inflammation ; NF-kB ; DNA repair
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Abstract Our laboratory has concentrated on the possible regulation the benzamides and nicotinamides may have on the processes of DNA repair and apoptosis. Recent reports [14-16] have suggested that both apoptosis and inflammation are regulated by the transcription factor NF-kB. We have initiated studies regarding the hypothesis that the benzamides and nicotinamides could inhibit the production of tumor necrosis factor alpha (TNFalpha) and the inflammatory response as well as induce apoptosis via inhibition of NF-kB. Our data have shown that nicotinamide and two N-substituted benzamides, metoclopramide (MCA) and 3-chloroprocainamide (3-CPA), gave dose dependent inhibition of lipopolysacharide induced TNFalpha in the mouse within the dose range of 10-500 mg/kg. Moreover, lung edema was prevented in the rat by 3 ï 50 mg/kg doses of 3-CPA or MCA, and 100-200 μM doses of MCA could also inhibit NF-kB in Hela cells. Taken together these data strongly support the notion that benzamides and nicotinamides have potent anti-inflammatory and antitumor properties, because their primary mechanism of action is regulated by inhibition at the gene transcription level of NF-kB, which in turn inhibits TNFalpha and induces apoptosis.
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    Growth arrest and induction of apoptosis in breast cancer cells by antisense depletion of protein kinase A-RIα subunit: p53-independent mechanism of action (1999)
    Springer
    Molecular and cellular biochemistry 195 (1999), S. 25-36 
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    ISSN: 1573-4919
    Keywords: antisense oligonucleotide ; apoptosis ; cAMP-dependent protein kinase ; cancer cells ; growth inhibition
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Abstract The enhanced expression of the RIα subunit of cyclic AMP-dependent protein kinase type 1 (PKA-I) has been correlated with cancer cell growth. We have investigated the effects of sequence-specific inhibition of RIα gene expression on the growth of MCF-7 human breast cancer cells. We report that RIα antisense treatment results in a reduction in RIα expression at both mRNA and protein levels and inhibition of cell growth. The growth inhibition was accompanied by changes in cell morphology, cleavage of poly(ADP-ribose) polymerase (PARP) and appearance of apoptotic nuclei. In addition, bcl-2 protein level was reduced and p53 expression increased in growth arrested cells. Interestingly, RIα antisense inhibited cell viability and induced apoptosis in the absence of p53, suggesting that these actions of RIα antisense are exerted independent of p53. In contrast, two- and four-base mismatched control oligonucleotides had no effect on either cell growth or morphology. These results demonstrate that the RIα antisense, which efficiently depletes the growth stimulatory molecule RIα, induces cell differentiation and apoptosis, providing a new approach to combat breast cancer cell growth.
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    TNF-α induced altered signaling mechanism in human neutrophil (1999)
    Springer
    Molecular and cellular biochemistry 197 (1999), S. 97-108 
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    ISSN: 1573-4919
    Keywords: neutrophil ; PKC ; TNF-α ; apoptosis ; DNA fragmentation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Abstract In the present study we investigated the TNF-α induced signal transduction mechanism in human neutrophil. Exogenously added TNF-α affects both PKC activity and its translocation from cytosol to the membrane. Endogenous protein phosphorylation pattern is inhibited in TNF-α induced neutrophil in Ca-dependent and Ca-independent manner, including a major 47 and 66 kDa cytosolic proteins, which may be implicated in superoxide anion generation. However TNF-α dose dependently enhances the expression of ζ-PKC isotype but not the β-PKC. Morphology and cell cytotoxicity are studied in TNF-α treated neutrophil to understand the TNF-α induced cell death or apoptosis and these experiment is further confirmed by DNA fragmentation analysis. These results clearly demonstrate that TNF-α induces cellular death of human neutrophil at least in part by enhanced expression of Ca-independent ζ-PKC. These observations provide an insight towards understanding the function of ζ-PKC in apoptotic pathway.
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    Diminished energy metabolism and enhanced apoptosis in livers of B6C3F1 mice treated with the antihepatocarcinogen rotenone (1999)
    Springer
    Molecular and cellular biochemistry 201 (1999), S. 25-32 
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    ISSN: 1573-4919
    Keywords: rotenone ; apoptosis ; oncogenes ; liver cancer
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Abstract Rotenone decreases the incidence of hepatocellular carcinoma and lowers rates of hepatocellular proliferation. In an effort to delineate mechanisms involved, the in vivo effect of rotenone on liver mitochondrial metabolism, apoptotic machinery as well as elements of the hepatic signal transduction pathways were investigated. Mitochondria from livers of male B6C3F1 mice fed a standard diet containing 600 ppm rotenone for 7 days were uncoupled or inhibited when succinate or glutamate plus malate were used as the substrate, respectively. These livers also showed a significant increase in apoptosis compared with control livers. Furthermore, rotenone increased the expression of c-myc mRNA to 5-fold of control values within 3 days, an effect which was still observed (3-fold) after 7 days. Levels of p53 mRNA were also increased 3-fold after 1 day, but declined to control levels by 7 days. Rotenone also caused a transient, yet marked increase in liver particulate glyceraldehyde phosphate dehydrogenase (GAPDH) protein expression, while it did not alter the expression of the cytosolic form of the enzyme. Conversely, mRNA of the proto-oncogene H-ras showed a decline of 35% after 3 days of rotenone treatment, and remained diminished for the duration of the experiment. These data suggest that rotenone may act as an anticancer agent by diminishing mitochondrial bioenergetics which prevents basal hepatocyte proliferation and lowers the threshold for liver cells with DNA damage to undergo apoptosis.
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    Preparative High-Resolution Two-Dimensional Electrophoresis Enables the Identification of RNA Polymerase B Transcription Factor 3 as an Apoptosis-Associated Protein in the Human BL60–2 Burkitt Lymphoma Cell Line (1999)
    Springer
    The protein journal 18 (1999), S. 225-231 
    Details
    ISSN: 1573-4943
    Keywords: Two-dimensional electrophoresis ; MALDI-MS ; apoptosis ; RNA polymerase B transcription factor 3
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Apoptosis or programmed cell death is essential in the process of controlling lymphocyte growth and selection. We identified RNA polymerase B transcription factor 3 (BTF3), which is associated with anti-IgM antibody-mediated apoptosis, using a subclone of the human Burkitt lymphoma cell line BL60. To identify the transcription factor BTF3, which is expressed only in minor amounts, we used preparative high-resolution two-dimensional gel electrophoresis (2DE) employing carrier ampholytes for isoelectric focusing. Comparison of the 2DE protein patterns from apoptotic and nonapoptotic cells showed BTF3 as a predominantly altered protein spot. The characterization of the differentially expressed transcription factor and 13 marker proteins described in this study were performed by internal Edman microsequencing and/or by peptide mass fingerprinting using matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS). The proteome analysis was significantly improved by performing the newly developed preparative high-resolution two-dimensional gels employing high protein concentrations.
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    Protein Kinase C Targeting in Antineoplastic Treatment Strategies (1999)
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    Investigational new drugs 17 (1999), S. 227-240 
    Details
    ISSN: 1573-0646
    Keywords: apoptosis ; protein kinase C ; sphingoid bases ; safingol ; diglyceride ; bryostatin 1 ; staurosporine ; 7-hydroxy staurosporine (UCN-01) ; 4′-N-benzoyl staurosporine (CGP-41251) ; calphostin C (UCN-1028c)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Abstract Neoplastic cell survival is governed by a balance between pro-apoptotic and anti-apoptotic signals. Noteworthy among several anti-apoptotic signaling elements is the protein kinase C (PKC) isoenzyme family, which mediates a central cytoprotective effect in the regulation of cell survival. Activation of PKC, and subsequent recruitment of numerous downstream elements such as the mitogen-activated protein kinase (MAPK) cascade, opposes initiation of the apoptotic cell death program by diverse cytotoxic stimuli. The understanding that the lethal actions of numerous antineoplastic agents are, in many instances, antagonized by cytoprotective signaling systems has been an important stimulus for the development of novel antineoplastic strategies. In this regard, inhibition of PKC, which has been shown to initiate apoptosis in a variety of malignant cell types, has recently been the focus of intense interest. Furthermore, there is accumulating evidence that selective targeting of PKC may prove useful in improving the therapeutic efficacy of established antineoplastic agents. Such chemosensitizing strategies can involve either (a) direct inhibition of PKC (e.g., following acute treatment with relatively specific inhibitors such as the synthetic sphingoid base analog safingol, or the novel staurosporine derivatives UCN-01 and CGP-41251) or (b) down-regulation (e.g., following chronic treatment with the non-tumor-promoting PKC activator bryostatin 1). In preclinical model systems, suppression of the cytoprotective function(s) of PKC potentiates the activity of cytotoxic agents (e.g., cytarabine) as well as ionizing radiation, and efforts to translate these findings into the clinical arena in humans are currently underway. Although the PKC-driven cytoprotective signaling systems affected by these treatments have not been definitively characterized, interference with PKC activity has been associated with loss of the mitogen-activated protein kinase (MAPK) response. Accordingly, recent pre-clinical studies have demonstrated that pharmacological disruption of the primary MEK-ERK module can mimic the chemopotentiating and radiopotentiating actions of PKC inhibition and/or down-regulation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1006328303451
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    Activation-Induced Apoptosis of Peripheral Lymphocytes Treated with 7-Hydroxystaurosporine, UCN-01 (1999)
    Springer
    Investigational new drugs 17 (1999), S. 335-341 
    Details
    ISSN: 1573-0646
    Keywords: UCN-01 ; IL-2 receptor ; Fas ; Fas-ligand ; apoptosis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Abstract 7-hydroxystaurosporine (UCN-01) is a new anticancer agentwhich exerts an inhibitory effect on cell cycle check points andis currently under phase I clinical trials in US and Japan.Preliminary clinical data indicated that UCN-01 remained inplasma at high concentrations for long periods of time. Thisunavoidable high plasma drug exposure is likely to lead tohematological toxicities in patients. In the present study,cultured human peripheral blood lymphocytes (PBLs) were used toevaluate the possible hematological toxicities of UCN-01treatment. UCN-01 induces apoptosis, and the induction ofapoptosis-related surface markers were also examined toinvestigate the involvement of these molecules in UCN-01-inducedapoptosis in PBLs. in vitroviability of PBLs wasdecreased by high dose of UCN-01 (25 μM, 3-day exposure). Thiseffect of UCN-01 was significantly suppressed by the presence ofhuman serum, suggesting that some specific inhibitory factor(s)in human serum may antagonize the lympholytic effect of UCN-01.The percentage of annexin V-positive PI-negative cells increasedwith exposure to UCN-01 in a time- and dose-dependent manner; byup to 30.3% after exposure to 25 μM UCN-01 for 3 days.At the same time, the expression of both interleukin-2 receptor(IL-2R, CD25) and Fas (CD95), analyzed by flow cytometry, wasinduced. Con A-stimulated PBLs were more sensitive toUCN-01-induced apoptosis than non-stimulated lymphocytes andUCN-01 increased the sFas-L released into culture medium from conA-stimulated PBLs. Therefore, lymphocyte depletion mediated byactivation-induced apoptosis is likely to occur in patientstreated with UCN-01 at high doses.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1006374118879
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    Influence of bcl-2 on antibody productivity in high cell density perfusion cultures of hybridoma (1999)
    Springer
    Cytotechnology 30 (1999), S. 95-106 
    Details
    ISSN: 1573-0778
    Keywords: apoptosis ; Bcl-2 ; fixed-bed ; hollow fibre ; hybridoma ; perfusion ; protein-free medium
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract Apoptosis is an active, genetically determined death mechanism which can be induced by a wide range of physiological factors and by mild stress. It is the predominant form of cell death during the production of antibodies from murine hybridoma cell lines. A number of studies have now demonstrated that the suppression of this death pathway, by means of over-expression of survival genes such as bcl-2, results in improved cellular robustness and antibody productivity during batch culture. In the present study, the influence of bcl-2 expression on hybridoma productivity in two high density perfusion bioreactor systems was investigated. In the first system, a fixed-bed reactor, the DNA content in the spent medium was 25% higher in the control (TB/C3-pEF) culture than that found in the bcl-2 transfected (TB/C3-bcl2) cultures at all perfusion rates. This is indicative of a higher level of cell death in the control cell line. The average antibody concentration for the TB/C3-pEF cell line was 14.9 mg L-1 at perfusion rates of 2.6 and 5.2 d-1. However, for the TB/C3-bcl2 cell line it was 33 mg L-1 at dilution rates of 2 and 4 d-1. A substantial increase in antibody concentration was also found in the Integra Tecnomouse hollow fibre reactor. The antibody titre in the TB/C3-bcl2 cassette was nearly 100% higher than that in the TB/C3-pEF cassette during the cultivation period which lasted 6 weeks. Clearly, these results demonstrate the positive impact of bcl-2 over-expression on production of antibody in hybridoma perfusion cultures.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1008055702079
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    Co-expression of bcl-2 and bag-1, apoptosis suppressing genes, prolonged viable culture period of hybridoma and enhanced antibody production (1999)
    Springer
    Cytotechnology 31 (1999), S. 143-151 
    Details
    ISSN: 1573-0778
    Keywords: antibody productivity ; apoptosis ; BAG-1 ; Bcl-2 ; cell survival ; hybridoma
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract Human bcl-2 and bag-1 DNA were introduced into mouse hybridoma 2E3- O cells and expressed. The expression of bcl-2 in BCMGneo-bcl2 transfectants was confirmed by ELISA and that of bag-1 in pZeo-bag1 was confirmed by western blotting. In batch cultures, the over-expression of bcl-2 prolonged the culture period by 2 days and co-expression of bcl-2 and bag-1 prolonged the culture period by 3 days. The delayed increase in the dead cell number in culture of the bcl-2 and bag-1 cotransfectant indicated the additional antiapoptosis effect of bcl-2 and bag-1 cotransfection in comparison with the bcl-2 only transfection. The bcl-2 transfectants (2E3O-Bcl2) produced antibody twofold per batch culture in comparison with 2E3-O cells transfected with BCMGSneo (2E3O-Mock). Enhancement of this MoAb production was due to the improved survival of the cells and was not due to stimulation of antibody production rate per cell by Bcl-2 expression. And the bcl-2 and bag-1 co-transfectant (2E3O-Bcl2-BAG1) produced antibody approximately fourfold of 2E3O-Mock per batch culture. Enhancement of this MoAb production was due to the improved survival of the cells and was partly due to stimulation of MoAb production rate per cell in the non-growing phase by the cotransfection. The method to engineer hybridoma cells genetically with bcl-2 and bag-1 for increasing viability and productivity would be widely applied for improving antibody productivity of hybridoma cultures.
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    URL: http://dx.doi.org/10.1023/A:1008080407581
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    A novel 96-well scintillation proximity assay for the measurement of apoptosis (1999)
    Springer
    Cytotechnology 31 (1999), S. 271-282 
    Details
    ISSN: 1573-0778
    Keywords: annexin V ; Apo-2 ligand ; apoptosis ; Cytostar-T® scintillating microplates ; flow cytometry ; lymphotoxin (LT)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract The translocation of phospholipids across the plasma membrane has been widely documented as one of the earliest measurable biochemical events of apoptosis. Using fluorescently labelled annexin V, which preferentially binds phosphatidylserine (PS) in the presence of Ca2+, the externalization of PS can be measured and apoptosis quantified using flow cytometry. Conventional detection methods utilizing annexin V, while faster than in situ DNA end-labelling or DNA laddering, require extensive sample preparation which may compromise samples and makes rapid, high volume screening prohibitive. This paper describes a novel assay for the measurement of apoptosis based upon binding of radiolabelled annexin V to apoptotic cells attached to the growth surface of a 96-well scintillating microplate (Cytostar-T®). We compared measurements of apoptosis made by flow cytometry to those obtained with the scintillating microplate in three model systems, treatment of: mouse connective tissue (L-M) cells with lymphotoxin (LT), human lung carcinoma (H460) cells with Apo-2 ligand and human umbilical vein endothelial (HUVE) cells with staurosporine. In this assay, we compare both direct and indirect labelling methods by utilizing either iodinated annexin V or biotinylated annexin V/[35S] streptavidin to radiolabel apoptotic cells. The signal detected is a direct consequence of the binding of annexin V to externalized PS on apoptotic cells and the proximity of the label to the base of the plate. Using this method, separation of bound and unbound radiolabel signal occurs directly within the well resulting in a sensitive assay that requires minimal manipulation and can accomodate a large number of samples.
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    URL: http://dx.doi.org/10.1023/A:1008053320396
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    Verotoxin/Globotriaosyl Ceramide Recognition: Angiopathy, Angiogenesis and Antineoplasia (1999)
    Springer
    Bioscience reports 19 (1999), S. 345-354 
    Details
    ISSN: 1573-4935
    Keywords: Glycolipid ; apoptosis ; intracellular traffic ; multidrug resistance ; ovarian carcinoma ; astrocytoma ; post transplant lymphoproliferative disease ; bone marrow purging
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Verotoxin (VT) is involved in the etiology of both hemorrhagic colitis and the hemolytic uremic syndrome which are microvasculopathies of the colon and pediatric renal glomerulus respectively. Thus, VT can be considered a vasotoxin. Cell sensitivity in vitro varies according to the receptor glycolipid (globotriaosyl ceramide-Gb3) expression and also to intracellular trafficking of the receptor/toxin complex, such that in highly sensitive cells, the toxin is targeted to the endoplasmic reticulum and nuclear envelope. Such cells include tumor cells which have become drug resistant. Thus Gb3 is upregulated in certain tumors and when such tumor cells become drug resistant, their sensitivity to verotoxin increases. This may be due to a direct role of the MDR1 drug efflux pump in glycolipid biosynthesis. In addition to the tumor tissue, the toxin receptor may also be expressed in the tumor neovasculature suggesting that activated endothelial cells may be verotoxin sensitive. Thus VT may have both a direct and indirect antineoplastic potential. VT has proved highly effective in a xenograft cancer model and the possible therapeutic use of VT is discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1020299819637
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    Ceramide Glycanase Activities in Human Cancer Cells (1999)
    Springer
    Bioscience reports 19 (1999), S. 449-460 
    Details
    ISSN: 1573-4935
    Keywords: ceramide glycanase ; cancer cells ; glycosphingolipid ; sphingosine ; ceramide ; apoptosis ; PPMP ; PDMP
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Ceramide glycanase (CGase) activities have been detected in different human tumor cells (colon, carcinoma Colo-205; neuroblastoma, IMR-32; breast cancer lines, SKBr3 and MCF7). However, the level of enzymatic activity is lower in these cells compared to that present in other mammalian tissues reported before (Basu, M., Kelly, P., Girzadas, M. A., Li, Z., and Basu, S. Methods Enzymol. (in press)). The majority of CGase activity was found in the 100,000g soluble supernatant fraction isolated from all these cell lines and tissues. Using the soluble enzyme, the requirement for optimum CGase activity was found to be consistent with previous observations found for rat and rabbit tissues (Basu, M., Dastgheib, S., Girzadas, M. A., O'Donnell, P. H., Westervelt, C. W., Li, Z., Inokuchi, J. I., and Basu, S. (1998) Acta Pol. Biochim. 42:327). The CGase activities from both Colo-205 and IMR-32 cells are optimum at a protein to detergent ratio of one. All the mammalian CGases, including human cancer cells, show an optimum pH between 5.5 and 5.8 in sodium acetate buffer. The CGase activities from cancer cells are found to be cation-independent; however, mercury, zinc, and copper ions seem to inhibit the enzyme activity substantially in both tumor cells lines. The mercury ion inhibition of CGase activities from all different sources indicates a possible structural homology in the CGase proteins. Radiolabeled substrates, labeled at the sphingosine double bond or at the 3-position of sphingosine without modifying double bond of sphingosine were used in this investigation. Both were active substrates with all enzyme preparations isolated from different cancer cells (apparent Km, 500 μM for nLcOse5[3H-DT]Cer and 350 μM for GgOse4[sph-3-3H]Cer with Colo-205 enzyme). Structural analogues of ceramide and sphingosine (L-PPMP, L-PDMP, alkylamines, and Tamoxifen) inhibited cancer cell CGase activities in vitro.
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    URL: http://dx.doi.org/10.1023/A:1020220524180
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    Adenosine-induced cell death: evidence for receptor-mediated signalling (1999)
    Springer
    Apoptosis 4 (1999), S. 197-211 
    Details
    ISSN: 1573-675X
    Keywords: Adenosine ; apoptosis ; necrosis ; physiopathological implications.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Adenosine modulates the proliferation, survival and apoptosis of many different cell types, ranging from epithelial, endothelial and smooth muscle cells, to cells of the immune and neural lineages. In this review, we critically discuss the available in vitro and in vivo data which support a role for adenosine in both development-associated apoptosis, and in diseases characterized by either pathologically increased cell death (e.g., ischemia, trauma and aging-associated neurodegeneration) or abnormally reduced spontaneous apoptosis (e.g., cancer). Particular emphasis is given to the possible role of extracellular adenosine receptors, since these may represent novel and attractive molecular targets for the pharmacological modulation of apoptosis. In some instances, adenosine-induced cell death has been demonstrated to require entry of the nucleoside inside cells; however, in many other cases, activation of specific adenosine extracellular receptors has been demonstrated. Of the four G protein-coupled adenosine receptors so far identified, the A2A and the A3 receptors have been specifically implicated in modulation of cell death. For the A3 receptor, results obtained by exposing both cardiomyocytes and brain astrocytes to graded concentrations of selective agonists suggest induction of both cell protection and cell death. Such opposite effects, which likely depend on the degree of receptor activation, may have important therapeutic implications in the pharmacological modulation of cardiac and brain ischemia. For the A2A receptor, recent intriguing data suggest a specific role in immune cell death and immunosuppression, which may be relevant to both adenosine-deaminase-immunodeficiency syndrome (a pathology characterized by accumulation of adenosine to toxic levels) and in tumors where induction of apoptosis via activation of specific extracellular receptors may be desirable. Finally, preliminary data suggest that, in a similar way to the adenosine-deaminase-immunodeficiency syndrome, the abnormal accumulation of adenosine in degenerative muscular diseases may contribute to muscle cell death. Although the role of adenosine receptors in this effect still remains to be determined, these data suggest that adenosine-induced apoptosis may also represent a novel pathogenic pathway in muscular dystrophies.
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    URL: http://dx.doi.org/10.1023/A:1009666707307
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    Apoptin®-induced apoptosis: a review (1999)
    Springer
    Apoptosis 4 (1999), S. 317-319 
    Details
    ISSN: 1573-675X
    Keywords: Anti-tumor therapy ; Apoptin® ; apoptosis ; Bcl-2 ; p53.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Apoptin, a protein encoded by an avian virus, induces apoptosis in various cultured human tumorigenic and/ or transformed cell lines, e.g. derived from breast and lung tumor, leukemia, lymphoma, osteosarcoma melanoma, cholangiocarcinoma, and hepatoma. In such cells, Apoptin induces p53-independent apoptosis, and the proto-oncogene Bcl-2 can accelerate this effect. The latter is surprising for, in general, Bcl-2 is known to inhibit e.g., p53-induced apoptosis. On the other hand, in normal non-transformed human cells, Apoptin is unable to induce apoptosis, even when Bcl-2 is over-expressed. In animal models Apoptin-induced apoptosis appears to be a safe and efficient anti-tumor agent. These data, in continuation with the observations that Apoptin is specifically stimulated by Bcl-2 in tumor cells, does not need p53, and is not inhibited by Bcr-Abl in these cells, imply that Apoptin is a potential anti-tumor therapy.
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    URL: http://dx.doi.org/10.1023/A:1009687019221
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    Apoptosis in ventricular myocytes: the role of tumor suppressor proteins (1999)
    Springer
    Apoptosis 4 (1999), S. 229-234 
    Details
    ISSN: 1573-675X
    Keywords: Adenovirus ; apoptosis ; Bcl-2 ; p53 ; Rb ; ventricular myocytes.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Apoptosis or programmed cell death is an important physiologic event crucial for the selective removal of damaged or unwanted cells from body tissues. In the cardiovascular system, apoptosis has been observed in the vasculature and myocardium. Untimely or inappropriate myocardial cell loss through an apoptotic process may contribute to ventricular remodeling and the ultimate demise of ventricular function following injury. Therapeutic interventions designed to modulate or prevent myocardial apoptotic cell loss may therefore prove beneficial in maintaining cardiac function. Incite into the molecular mechanisms that govern apoptosis in mammalian cells has led to the identification of several key factors that promote or prevent the apoptotic process. In this report, we discuss putative regulators of cardiac cell apoptosis with specific reference to the tumor suppressor proteins, p53 and Rb. The interplay between these factors, as well as the anti-apoptotic molecules related to the Bcl-2 the family are discussed in the context of the heart under normal and disease conditions.
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    URL: http://dx.doi.org/10.1023/A:1009640124029
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    Tau protein is involved in the apoptotic process induced by anti-microtubule agents on neuroblastoma cells (1999)
    Springer
    Apoptosis 4 (1999), S. 47-58 
    Details
    ISSN: 1573-675X
    Keywords: Anti-microtubule agents ; apoptosis ; doxorubicin ; neuroblastoma ; tau ; taxoid
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Paclitaxel and docetaxel are potent anti-microtubule and antimitotic agents that induce apoptosis in bone marrow-derived cells and epithelial cells. This study examined apoptosis induced by anti-microtubule agents in the neuroblastoma SK-N-SH cell line with a special focus on tau protein which is one of the main Microtubule-Associated- Proteins (MAPs) in neuronal cells. In time, treatment with 1 μM paclitaxel successively induced formation of bundles, then pseudo-asters concomitantly with mitotic block and phosphorylation of bcl-2 (48 h), then phosphorylation of tau and externalization of phosphatidylserine at the early phase of apoptosis (72 h) and finally DNA fragmentation (96 h). Similar results were obtained with 0.5 μM vinorelbine. Paclitaxel induced a lower increase in tau phosphorylation in differentiated SK-N-SH/RA+ cells which are less sensitive to apoptosis. Moreover, doxorubicin whose mechanism of action is independent of microtubules also induced immunostaining of tau at 72 h treatment. In conclusion, our results on neuroblastoma cells show that overexpression of hyperphosphorylated tau is involved in the apoptotic process induced by anti-microtubule agents and may be extended to others cytostatic drugs. Thus, tau protein may play a role in the cellular events observed in neuroblastoma cells undergoing apoptosis.
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    URL: http://dx.doi.org/10.1023/A:1009682116158
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    IL-3 induces apoptosis in a ras-transformed myeloid cell line (1999)
    Springer
    Apoptosis 4 (1999), S. 71-80 
    Details
    ISSN: 1573-675X
    Keywords: abl ; apoptosis ; interleukin-3 ; oncogenes ; ras.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Growth factors promote cell survival and proliferation. Homeostasis is maintained by programmed cell death which occurs when the growth stimulus is withdrawn, in response to negative growth regulators such as interferons, TNF-α and CD95 ligand, or following differentiation. Although acutely-transforming oncogenes often overcome the need for growth factors, growth regulatory cytokines can influence proliferative responses of transformed cells. In this study we investigated the effects of IL-3 on the proliferative responses of parental bone marrow-derived 32D cells and cells transformed with ras and abl oncogenes. We show that treatment of ras-transformed 32D cells with IL-3 reduced proliferative responses and decreased colony-forming ability. These effects were exacerbated in the absence of serum and associated with inhibition of tyrosine kinase activity, down-regulation of RAS and MYC expression, and induction of apoptosis as indicated by DNA fragmentation. In contrast, treatment of parental 32D cells with IL-3, which is obligatory for cell survival and proliferation, increased tyrosine kinase activity, upregulated MYC and RAS expression and maintained DNA integrity. With abl-transformed cells, proliferation and colony-forming ability were also inhibited by IL-3. Tyrosine kinase activity and MYC expression were reduced, but early apoptosis was not evident. Calcium uptake however, was stimulated by IL-3 in both parental and oncogene-transformed cells. These results suggest that threshold levels of tyrosine kinase activity are necessary for cell survival and proliferation and that with ras-transformed cells, IL-3 treatment may result in this threshold being breached. We conclude that in some situations, growth-promoting cytokines can inhibit proliferation of transformed cells and induce cell death by apoptosis.
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    URL: http://dx.doi.org/10.1023/A:1009686220607
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    Ameloblast apoptosis and IGF-1 receptor expression in the continuously erupting rat incisor model (1999)
    Springer
    Apoptosis 4 (1999), S. 441-447 
    Details
    ISSN: 1573-675X
    Keywords: ameloblasts ; amelogenesis ; apoptosis ; insulin-like growth factor.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Enamel-producing cells (ameloblasts) pass through several phenotypic and functional stages during enamel formation. In the transition between secretory and maturation stages, about one quarter of the ameloblasts suddenly undergo apoptosis. We have studied this phenomenon using the continuously erupting rat incisor model. A special feature of this model is that all stages of ameloblast differentiation are presented within a single longitudinal section of the developing tooth. This permits investigation of the temporal sequence of gene and growth factor receptor expression during ameloblast differentiation and apoptosis. We describe the light and electron microscopic morphology of ameloblast apoptosis and the pattern of insulin-like growth factor-1 receptor expression by ameloblasts in the continuously erupting rat incisor model. In the developing rat incisor, ameloblast apoptosis is associated with downregulated expression of the insulin-like growth factor-1 receptor. These data are consistent with the hypothesis that ameloblasts are “hard wired” for apoptosis and that insulin-like growth factor-1 receptor expression is required to block the default apoptotic pathway. Possible mechanisms of insulin-like growth factor-1 inhibition of ameloblast apoptosis are presented. The rat incisor model may be useful in studies of physiological apoptosis as it presents apoptosis in a predictable pattern in adult tissues.
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    URL: http://dx.doi.org/10.1023/A:1009600409421
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    Apoptotic cell death and related gene expression in metastatic tumors of AKR lymphomas of varying malignancy (1999)
    Springer
    Apoptosis 4 (1999), S. 429-440 
    Details
    ISSN: 1573-675X
    Keywords: AKR lymphoma malignancy variants ; apoptosis ; apoptosis-related gene expression ; tumor progression
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Resistance to apoptosis may be related to tumor progression, due to the implications it might have on both tumor mass and genetic instability. We compared the tendency to spontaneous apoptosis and the proliferative capacity of metastatic growths of several AKR lymphoma variants (TAU-45, TAU-47, TAU-44, TAU-33, TAU-42 and TAU-46, in the order of increasing metastatic potential). We further compared the expression of several apoptosis-related genes. Cell proliferative capacity did not appear to determine malignant behavior since, on the whole, a decrease in S + G2M fraction was observed with increasing malignancy. Sensitivity to apoptotic cell death decreased with increasing malignancy when comparing the TAU-45, TAU-47, TAU-44 and TAU-33 variants, suggesting a role of reduced apoptosis in this T-cell lymphoma. An increase in Bcl-2 content with increasing aggressiveness among these variants, implicates this protein in this tumor progression-related resistance to apoptosis. However, the two variants of highest malignancy, TAU-42 and TAU-46, did not follow the same trend, since they displayed a relatively high content in apoptotic cells and a low Bcl-2 content. Fas receptor expression did not correlate with tendency to apoptosis, indicating that malignant behavior in the AKR lymphoma does not depend on CD95/Fas/APO1 downregulation. Overexpression of p53 was observed only in one of the variants of lowest malignancy.
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    URL: http://dx.doi.org/10.1023/A:1009648325350
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    Signalling steps in apoptosis by ether lipids (1999)
    Springer
    Apoptosis 4 (1999), S. 419-427 
    Details
    ISSN: 1573-675X
    Keywords: Anti-oxidant defence ; apoptosis ; ether lipids ; glutathione ; ionising radiation ; stress.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract We have investigated the mechanisms of induction of apoptosis by the antineoplastic ether lipid ET-18-OCH3 (ALP) in sensitive S49wt mouse lymphoma cells and ALP-resistant S49ar variants, both with wild-type p53, and in related L1210 cells with mutated p53. Ether lipid-resistant S49ar cells were cross-resistant to extracellular stress factors (cold shock, heat shock, H2O2, dimethylsulfoxide) and to radiation-induced apoptosis but not to physiological apoptotic signals (dexamethasone, growth factor deprivation, thapsigargin, C2-ceramide) and expressed similar levels of the apoptosis-regulating proteins Bcl-2, Bcl-X, Bax, Bad and Bak as did the parent S49wt cells. The uptake of [3H]-ALP was strongly reduced in the stress-resistant cells but this was not associated with significant differences in membrane cholesterol:phospholipid content nor in membrane microviscosity. In S49ar cells the activity of the antioxidant enzyme glutathione peroxidase (GSH-Px) was increased 4-fold and depletion of glutathione with the drug L-buthionine-S-R-sulfoximine (L-BSO) lowered the resistance of S49ar cells to ALP, stress factors and ionising radiation. The results indicate that ether lipids induce apoptosis by imposing a special form of physico-chemical stress, mediated by reactive oxygen species but independent of p53 status. The capacity of glutathione-dependent anti-oxidant defence appeared an important and shared determinant of the sensitivity to ether lipids, several types of extracellular stress and ionising radiation.
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    URL: http://dx.doi.org/10.1023/A:1009644208512
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    Sequential occurrence of mitochondrial and plasma membrane alterations, fluctuations in cellular Ca2+ and pH during initial and later phases of cell death (1999)
    Springer
    Apoptosis 4 (1999), S. 455-460 
    Details
    ISSN: 1573-675X
    Keywords: Annexin V ; apoptosis ; flow cytometry ; intracellular Ca2+ ; intracellular pH ; mitochondrial membrane potential.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract The sequential occurrence of plasma and mitochondrial membrane alterations, intra-cellular pH shifts and changes in intracellular Ca2+ concentration after induction of cell death was monitored by flow cytometry in Jurkat and HSB2-cells. Cell death was induced by treatment with anti-Fas antibodies or by irradiation. Phosphatidylserine (PS) exposure and plasma membrane integrity were measured with FITC-Annexin V adhesion and by Propidium Iodide exclusion. Transition of the mitochondrial membrane potential was monitored by the occurrence of decay of DiOC6 fluorescence. Intracellular pH shifts were monitored by changes in the ratio of fluorescence at 575 nm and at 635 nm of SNARF-1-AM. Fluctuations in intracellular Ca2+ concentration were established by changes in Fura red quenching. The Jurkat cells were sensitive to anti-Fas treatment, while HSB-2 cells were not. HSB-2 cells appeared more sensitive to radiation damage than Jurkat cells. In all experiments the transition of mitochondrial membrane potential occurred first, almost immediately followed by PS exposure. Fluctuations in intracellular Ca2+ concentration occurred later and were less outspoken. A decrease in intracellular pH occurred not earlier than 24 hours after anti-Fas treatment. Chelation of intracellular Ca2+ concentration with BAPTA-AM had no effect on the time sequence of cell death related events.
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    URL: http://dx.doi.org/10.1023/A:1009604510329
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    Pharmacodynamics and Toxicodynamics of Drug Action: Signaling in Cell Survival and Cell Death (1999)
    Springer
    Pharmaceutical research 16 (1999), S. 790-798 
    Details
    ISSN: 1573-904X
    Keywords: MAPK ; caspases ; chemopreventive agents ; phase II drug metabolizing enzymes ; apoptosis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract In therapeutic response to drugs, the plasma concentration range leads to the establishment of a safe and effective dosage regimen. Our hypothesis is that by studying drug concentration-dependent effect on signal transduction mechanisms, a better understanding of the beneficial pharmacodynamic and adverse toxicodynamic responses elicited by the drug may be achieved. Using two classes of chemopreventive compounds (phenolic antioxidants and isothiocyanates), we illustrate the potential utility of two signal transduction pathways elicited by these agents to predict the pharmacodynamic effect (induction of Phase II drug metabolizing enzymes) and the potential toxicodynamic response (stimulation of caspase activity and cytotoxic cell death). At lower concentration, phenolic antioxidants and isothiocyanates activate mitogen-activated protein kinase (MAPK; extracellular signal-regulated protein kinase 2, ERK2; and c-Jun N-terminal kinase 1, JNK1) in a concentration-and time-dependent manner. The activation of MAPK by these compounds may lead to the induction of cell survival/protection genes such as c-jun, c-fos, or Phase II drug metabolizing enzymes. However, at higher concentrations, these agents activate another signaling molecule, ICE/Ced3 cysteine protease enzymes (caspases) leading to apoptotic cell death. The activation of these pathways may dictate the fate of the cells/tissues upon exposure to drugs or chemicals. At lower concentrations, these compounds activate MAPK leading to the induction of Phase II genes, which may protect the cells/tissues against toxic insults and therefore may enhance cell survival. On the other hand, at higher concentrations, these agents may activate the caspases, which may lead to apoptotic cell death, and have toxicity. Understanding the activation of these and other signal transduction events elicited by various drugs and chemicals may yield insights into the regulation of gene expression of drug metabolizing enzymes and cytotoxicity. Thus, the study of signaling events in cell survival (hemeostasis) and cell death (cytotoxicity) may have practical application during pharmaceutical drug development.
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    URL: http://dx.doi.org/10.1023/A:1011953431486
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    Effect of ethrel on apoptosis in carrot protoplasts (1999)
    Springer
    Plant growth regulation 27 (1999), S. 119-123 
    Details
    ISSN: 1573-5087
    Keywords: apoptosis ; carrot protoplast ; DNA ladder ; ethrel ; ethylene ; nucleus condensation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract In recent years, apoptosis has been reported to exist in plants during normal development and in response to stress. However, little is known about the relation of hormones to this form of programmed cell death. Here, we report examination of characteristics of apoptosis in carrot protoplasts induced by ethylene evolved from ethrel (2-chloroethylphosphonic acid). Nucleus condensation and DNA ladders were observed, and neutral comet assay, which detects DNA cleavage, also provided evidence that ethrel treatment resulted in nuclear DNA fragmentation. Strikingly, a close correlation between the incidence of DNA comets and the percentage of apoptotic protoplasts was shown in ethrel-treated carrot protoplasts. In conclusion, this study demonstrated that ethylene is an active inducer of apoptosis in carrot protoplasts, and that ethylene-induced plant cell death showed characteristics similar to those of apoptosis in animals.
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    URL: http://dx.doi.org/10.1023/A:1006105101813
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    Mitochondrial Events in the Life and Death of Animal Cells: A Brief Overview (1999)
    Springer
    Journal of bioenergetics and biomembranes 31 (1999), S. 291-304 
    Details
    ISSN: 1573-6881
    Keywords: Cell death ; aging ; necrosis ; apoptosis ; mitochondria ; oxidative phosphorylation ; electron transport chain ; ATP synthase ; cytochrome c ; mitochondrial DNA ; reactive oxygen species (ROS)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Physics
    Notes: Abstract Traditionally, mitochondria have been viewed as the “powerhouse” of the cell, i.e., the site of theoxidative phosphorylation machinery involved in ATP production. Consequently, much of theresearch conducted on mitochondria over the past 4 decades has focused on elucidating both thosemolecular events involved in ATP synthesis by oxidative phosphorylation and those involved inthe biogenesis of the oxidative phosphorylation machinery. While monumental achievements havebeen made, and continue to be made, in the study of these remarkable but extremely complexprocesses essential for the life of most animal cells, it has been only in recent years that a largebody of biological and biomedical scientists have come to recognize that mitochondria participatein other important processes. Two of these are cell death and aging which, not surprisingly, are relatedprocesses both involving, in part, the oxidative phosphorylation machinery. This new awareness hassparked a new and growing area of mitochondrial research, that has become of great interest to awide variety of scientists ranging from those involved in elucidating the role of mitochondria incell death and aging to those interested in either suppressing or facilitating these processes as itrelates to identifying new therapies or drugs for human disease. It is the purpose of this briefintroductory review to provide an overview of those mitochondrial events involved in the life anddeath of animal cells and to indicate how these events might relate to the human aging process.Much more is known, much remains controversial, and even more remains to be learned as indicatedin the excellent set of minireviews that follow.
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    Mitochondria at the Crossroad of Apoptotic Cell Death (1999)
    Springer
    Journal of bioenergetics and biomembranes 31 (1999), S. 321-326 
    Details
    ISSN: 1573-6881
    Keywords: Mitochondria ; apoptosis ; caspases ; cytochrome c ; Fas ; bcl-2
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Physics
    Notes: Abstract In the past few years, it has become widely appreciated that apoptotic cell death generallyinvolves activation of a family of proteases, the caspases, which undermine the integrity ofthe cell by cleavage of critical intracellular substrates. Caspases, which are synthesized asinactive zymogens, are themselves caspase substrates and this cleavage leads to their activation.Hence, the potential exists for cascades of caspases leading to cell death. However, it has beenrecently recognized that another, perhaps more prominent route to caspase activation, involvesthe mitochondria. Upon receipt of apoptotic stimuli, either externally or internally generated,cells initiate signaling pathways which converge upon the mitochondria to promote release ofcytochrome C to the cytoplasm; cytochrome c, thus released, acts as a potent cofactor incaspase activation. Even cell surface “death receptors” such as Fas, which can trigger directcaspase activation (and potentially a caspase cascade), appear to utilize mitochondria as partof an amplification mechanism; it has been recently demonstrated that activated caspases cancleave key substrates to trigger mitochondrial release of cytochrome c, thereby inducing furthercaspase activation and amplifying the apoptotic signal. Therefore, mitochondria play a centralrole in apoptotic cell death, serving as a repository for cytochrome c.
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    Mitochondrial Uncoupling: Role of Uncoupling Protein Anion Carriers and Relationship to Thermogenesis and Weight Control “The Benefits of Losing Control” (1999)
    Springer
    Journal of bioenergetics and biomembranes 31 (1999), S. 493-506 
    Details
    ISSN: 1573-6881
    Keywords: Energy expenditure ; reactive oxygen species ; cellular viability ; apoptosis ; necrosis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Physics
    Notes: Abstract Uncoupling proteins, a subgroup of the mitochondrial anion transporter superfamily, have beenidentified in prokaryotes, plants, and mammalian cells. Evolutionary conservation of thesemolecules reflects their importance as regulators of two critical mitochondrial functions, i.e.,ATP synthesis and the production of reactive oxygen species (ROS). Although the amino acidsequences of the three mammalian uncoupling proteins, UCP1, UCP2 and UCP3, are verysimilar, each homolog is the product of a unique gene and important differences have beendemonstrated in their tissue-specific expression and regulation. UCP1 and UCP3 appear to bekey regulators of energy expenditure, and hence, nonshivering thermogenesis, either in brownadipose tissue (UCP1) or skeletal muscle (UCP3). UCP2 is expressed more ubiquitously,although generally at low levels, in many tissues. There is conflicting evidence about itsimportance as a regulator of resting metabolic rate. However, evidence suggests that thishomolog might modulate the mitochondrial generation of ROS in some cell types, includingmacrophages and hepatocytes. While the induction of various uncoupling protein homologsprovides adaptive advantages, both to the organism (e.g., thermogenesis) and to individual cells(e.g., reduced ROS), increased uncoupling protein activity also increases cellular vulnerability tonecrosis by compromising the mitochondrial membrane potential. This narrow “risk—benefit”margin necessitates tight control of uncoupling protein activity in order to preserve cellularviability and much remains to be learned about the regulatory mechanisms involved.
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    Hepatotoxicity due to mitochondrial dysfunction (1999)
    Springer
    Cell biology and toxicology 15 (1999), S. 367-373 
    Details
    ISSN: 1573-6822
    Keywords: apoptosis ; drugs ; hepatitis ; mitochondria ; steatosis ; steatohepatitis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Mitochondria are involved in fatty acid β-oxidation, the tricarboxylic acid cycle, and oxidative phosphorylation, which provide most of the cell energy. Mitochondria are also the main source of reactive oxygen species in the cell and are involved in cell demise through opening of the mitochondrial permeability transition pore. It was therefore to be expected that mitochondrial dysfunction could be a major mechanism of drug-induced liver disease. Microvesicular steatosis (which may cause liver failure, coma, and death) is the consequence of severe impairment of mitochondrial β-oxidation. Endogenous compounds (such as cytokines or female sex hormones) or xenobiotics (including toxins such as ethanol and drugs such as aspirin, valproic acid, ibuprofen, or zidovudine) can inhibit β-oxidation directly or through a primary effect on the mitochondrial genome or the respiratory chain itself. In some patients, infections and cytokines, or inborn errors of β-oxidation enzymes or the mitochondrial genome, may favor the appearance of drug-induced microvesicular steatosis. Nonalcoholic steatohepatitis may develop under conditions causing prolonged, microvesicular, and/or macrovacuolar steatosis. In this condition, chronic impairment of mitochondrial β-oxidation (causing steatosis) and the respiratory chain (increasing the production of ROS) lead to lipid peroxidation, which, in turn, may cause the diverse lesions of steatohepatitis, namely, necrosis, inflammation, Mallory's bodies, and fibrosis. Finally, mitochondria are involved in several forms of drug-induced cytolytic hepatitis, through inhibition or uncoupling of respiration or through a drug-induced or reactive metabolite-induced mitochondrial permeability transition. The latter effect commits hepatocytes to either apoptosis or necrosis, depending on the number of organelles that have undergone the permeability transition.
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    The Involvement of p53 in Dopamine-Induced Apoptosis of Cerebellar Granule Neurons and Leukemic Cells Overexpressing p53 (1999)
    Springer
    Cellular and molecular neurobiology 19 (1999), S. 261-276 
    Details
    ISSN: 1573-6830
    Keywords: Parkinson's disease ; catecholamines ; oxidative metabolites ; phosphorylation ; DNA damage ; apoptosis ; p53
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract 1. The pathogenesis of the selective degeneration of the dopaminergic neurons in Parkinson's disease is still enigmatic. Recently we have shown that dopamine can induce apoptosis in postmitotic neuronal cells, as well as in other cellular systems, thus suggesting a role for this endogenous neurotransmitter and associated oxidative stress in the neuronal death process. 2. Dopamine has been shown to be capable of inducing DNA damage through its oxidative metabolites. p53 is a transcription factor that has a major role in determining cell fate in response to DNA damage. We therefore examined the possible correlation between dopamine-triggered apoptosis, DNA damage and levels of total phosphorylated p53 protein in cultured mouse cerebellar granule neurons. 3. Marked DNA damage and apoptotic nuclear condensation and fragmentation were detected within several hours of exposure to dopamine. An associated marked threefold increase in p53 phosphorylation was observed within this time window. Using a temperature-sensitive p53 activation system in leukemia LTR6 cells, were found that p53 inactivation dramatically attenuated dopamine toxicity. 4. We therefore conclude that DNA damage and p53 activation may have a role in mediating dopamine-induced apoptosis. Modulation of the p53 system may therefore have a protective role against the toxicity of this endogenous neurotransmitter and associated oxidative stress.
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    URL: http://dx.doi.org/10.1023/A:1006933312401
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    Culture filtrates of Aspergillus fumigatus induce different modes of cell death in human cancer cell lines (1999)
    Springer
    Mycopathologia 146 (1999), S. 67-74 
    Details
    ISSN: 1573-0832
    Keywords: apoptosis ; Aspergillus fumigatus ; cell death ; culture filtrate(s) ; necrosis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Aspergillus fumigatus culture filtrate (CF) has a potent cytotoxic effect on three human cancer cell lines (DLKP, A549 and HEp-2) and initiates cell death by apoptosis but the execution of the apoptotic process is incomplete. DLKP cells treated with A. fumigatus CF demonstrate features associated with apoptosis but cytoplasmic and nuclear fragmentation were not observed and cells ultimately underwent necrosis. The apoptotic process commenced in A549 and HEp-2 cells upon exposure to CF, cell shrinkage was observed but membrane blebbing and apoptotic body formation were not detected and detached cells died by necrosis. In contrast, extensive nuclear fragmentation and apoptotic body formation were evident in DLKP and A549 cells treated with anti-neoplastic agents. This work indicates that A. fumigatus CF is cytotoxic to cancer cells and can initiate apoptosis but that the complete apoptotic pathway is not followed.
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    URL: http://dx.doi.org/10.1023/A:1007092112873
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    Non-isothermal Decomposition Kinetics of Complex of Co(III), Ni(II) with O,O'-dialkyldithiophosphates and Adducts of Ni-complex with Pyridines (1999)
    Springer
    Journal of thermal analysis and calorimetry 55 (1999), S. 197-203 
    Details
    ISSN: 1572-8943
    Keywords: adducts ; cobalt complex ; DSC ; kinetics ; nickel complex ; O,O'-dialkyldithiophosphate ; pyridine ; TG-DTG
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Thermal behaviour of tri(O,O'-diisopropyldithiophosphate)cobalt(III), Co(dptp)3 and bis (O,O'-diethyldithiophosphate)nickel(II), Ni(detp)2 and its adducts with pyridine, Ni(detp)2(py)2 or 4-methylpyridine, Ni(detp)(mpy)2 in a dynamic nitrogen atmosphere was investigated by TG-DTG and DSC techniques, which showed a medium endothermic peak for the evolution process of pyridine(or 4-methylpyridine) and a strong exothermic peak for that of O,O'-diethyldithiophosphate. The thermal stability and decomposition patterns for these compounds were compared and interpreted in terms of structural features such as bond character and steric effects. The kinetic parameters and mechanisms of every decomposition stage involved for all these complexes were obtained employing the non-isothermal kinetic analysis method suggested by Malek et al., which showed the kinetics mechanism for pyrolysis of pyridine(or 4-methylpyridine) is an S-B empirical model with lower activation energy, while that of O,O'-dialkyldithiophosphate is a diffusion model. These results are in accord with the fact that two ligands are of different type.
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    Effect of Solvent Composition on DSC Exothermic Peak of Human Serum Albumin Suspended in Pyridine-n-Hexane Mixtures (1999)
    Springer
    Journal of thermal analysis and calorimetry 55 (1999), S. 85-92 
    Details
    ISSN: 1572-8943
    Keywords: DSC ; exothermic peak ; human serum albumin ; non-equilibrium state ; pyridine-n-hexane mixtures
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Human serum albumin (HSA) immersed in pyridine-n-hexane mixtures was analyzed using differential scanning calorimetry (DSC). State of the solid HSA in organic solvent mixtures is the non-equilibrium state which is seen as the exothermic peak on the DSC curves. The enthalpy change corresponding to this exothermic peak approaches zero when going from pure pyridine to pure n-hexane. Dependence of the enthalpy change on the pyridine concentration is suggestive that the non-equilibrium state of the immersed HSA results from the HSA-pyridine interactions 'frozen' at the lower temperature. Most likely the temperature-initiated exothermic peak observed on the DSC curves reflects the swelling of HSA by pyridine.
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    Effect of Heating Rate on Crystallization Kinetics of Amorphous Al91La5Ni4 Alloys by DSC (1999)
    Springer
    Journal of thermal analysis and calorimetry 56 (1999), S. 437-446 
    Details
    ISSN: 1572-8943
    Keywords: Al-La-Ni amorphous ribbons ; DSC ; heating rate ; non-isothermal crystallization kinetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Crystallization kinetics of Al91La5Ni4 amorphous ribbons produced by a melt-spinning method were studied by DSC analysis and X-ray diffraction. The effect of heating rate (from 4 to 200°C min-1) was investigated in the temperature range from 298 to 700 K. Increases the heating rate from 4 to 200°C min-1 resulted in increases of the temperature difference between the two stages of the transformation process: crystallization of Al and crystallization of the Al compounds from 148.9 to 167.4 K. The apparent activation energies for the first step, related to Al crystallization, and to the second step related to crystallization of Al4La and Al3Ni, were found to be 161±9 and 199±10 kJ mol-1, respectively. The results indicate the possibility of tailoring the heating treatment to produce the required fraction of the amorphous phase.
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    DSC and Electronmicroscopic Investigation of Dispersion-Type Processed Cheeses Made Without Peptization (1999)
    Springer
    Journal of thermal analysis and calorimetry 56 (1999), S. 1211-1216 
    Details
    ISSN: 1572-8943
    Keywords: dispersion-type processed cheese ; DSC ; ELMI
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract In contrast with the traditional method of cheese processing, where Ca breaks down from the protein chain and protein is peptized, a new technology has been elaborated, during which cheese is dispersed without phosphate-containing processing salt, when the gel is formed by plant hydrocolloids. Raw material of constant composition was processed with a phosphate-containing salt or in the presence of hydrocolloids. Thermodynamic processes occurring during the processing and in the end-products were examined by an ultra-sensitive micro DSC method. The structures of end-products were also investigated by electronmicroscopy. The temperature ranges of the endothermal processes indicating the transformations of protein and hydrocolloids can be distinguished: 81-90°C for peptization processing and 61-72°C for processing without peptization. The differences are less in the end-products: 75-87°C in traditional processed cheese and 68-74°C in processed cheeses made without peptization. In contrast with the spongy structure of traditional processed cheeses consisting of peptized proteins, processed cheeses made without peptization involve structure-forming elements created by the interaction of linear macromolecules of hydrocolloids and cheese proteins.
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    DSC Screening of Potential Prochlorperazine-Excipient Interactions in Preformulation Studies (1999)
    Springer
    Journal of thermal analysis and calorimetry 56 (1999), S. 1317-1322 
    Details
    ISSN: 1572-8943
    Keywords: cyclodextrins ; drugs ; DSC ; excipients ; prochlorperazine
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Differential scanning calorimetry was used to examine the thermal behaviour of mixtures of the drug prochlorperazine with standard excipients, to assess potential interactions, and of mixtures with cyclodextrins, to investigate inclusion complexation which could increase the photostability of the drug. For most of the excipients (magnesium stearate, stearic acid, Explotab®, Ac-Di-Sol®, Encompress® and Ludipress®, lactose and Starch 1500) disappearance or broadening of the melting endotherm of the drug indicated interactions. Lubritab® was the only 'inert' excipient tested. Mixtures of prochlorperazine and the cyclodextrins gave incomplete inclusion complexation as shown by only partial disappearance of the melting endotherm of the drug.
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    Melting of PbBr2: A DSC investigation (1999)
    Springer
    Journal of thermal analysis and calorimetry 57 (1999), S. 599-605 
    Details
    ISSN: 1572-8943
    Keywords: DSC ; lead bromide ; melting ; systematic error
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The melting of PbBr2 in sealed crucibles was investigated by means of DSC. Three factors were considered to affect melting point: i) impurities, ii) the bromine pressure over the PbBr2, and iii) photolysis. Both crystals and powders were investigated. The peak of the melting changed after sample grinding. The bromine pressure over the PbBr2 was found to cause a significant error in the determination of the melting point. Lead bromide melts at 370.6±0.2°C. The heat of melting is 42.9±1.8 J g−1.
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    DSC Studies of the Effects of Cisplatin and Transplatin on G-Actin (1999)
    Springer
    Journal of thermal analysis and calorimetry 58 (1999), S. 243-248 
    Details
    ISSN: 1572-8943
    Keywords: actin ; cisplatin ; DSC ; thiol ; transplatin
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The effects of cisplatin and its trans isomer transplatin on the thermal denaturation of G-actin were studied with a Micro DSC-III differential scanning calorimeter. The denaturation enthalpy of G-actin was found to be 12 J g−1, and the denaturation temperature was 328 K. The thermal denaturation curve showed that increasing cisplatin concentration decreased the enthalpy change. However, after the ratio of cisplatin to G-actin attained 8:1 (mol:mol), the denaturation enthalpy no longer decreased. Transplatin decreased the enthalpy change more rapidly. In contrast with cisplatin, the denaturation peak at 328 K disappeared, and a strong exothermic peak appeared at 341 K when the ratio of transplatin to G-actin was 8:1 (mol:mol). The enthalpy change was 75 J g−1, which is far in excess of the range of weak interactions. This strong exothermic phenomenon probably reflects the agglutination of protein. The effects of cisplatin and transplatin on the number of the free thiol groups of G-actin are discussed.
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    Thermal Behavior of Nafion Membranes (1999)
    Springer
    Journal of thermal analysis and calorimetry 58 (1999), S. 569-577 
    Details
    ISSN: 1572-8943
    Keywords: counterion effect ; DSC ; membrane ; Nafion-H ; Nafion salts ; TG
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The thermal behavior of Nafion-117 membranes was investigated by thermogravimetric analysis (TG) and differential scanning calorimetry (DSC). TG measurements revealed that the mechanism of thermal degradation of a Nafion membrane in the acid form is different from that of Nafion in the sodium form. The DSC curves for the first heating, for both acid and salt forms, display two endothermic peaks, near 120 and 230°C. The high-temperature peak was assigned to the crystalline domains melting in Nafion, and the low-temperature peak was attributed to a transition into ionic clusters, since this transition exhibits significant changes depending on the nature of the counterion and the degree of hydration.
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    Fas-mediated apoptosis is attenuated in preneoplastic GST-P-positive hepatocytes isolated from diethylnitrosamine-treated rats (1999)
    Springer
    Cell biology and toxicology 15 (1999), S. 239-247 
    Details
    ISSN: 1573-6822
    Keywords: apoptosis ; bile acid ; diethylnitrosamine ; enzyme-altered foci ; Fas ; hepatocytes ; p53 ; preneoplastic
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Previous reports have indicated that apoptosis is selectively decreased in enzyme-altered foci (EAF) in the livers of rats treated with a carcinogen. Here we have investigated the effects of an anti-Fas antibody (anti-Fas Ab) on EAF cells in vitro. Hepatocytes were isolated from rats treated repeatedly with diethylnitrosamine (DEN), whose livers contained glutathione S-transferase P (GST-P)-positive EAF. Subsequently, primary cultures of GST-P-positive and GST-P-negative hepatocytes were established and exposed to anti-Fas Ab. Anti-Fas Ab (4 μg/ml) preferentially induced apoptosis in GST-P-negative cells. Furthermore, GST-P-positive cells were shown to be resistant to p53-mediated apoptosis. We conclude that EAF hepatocytes are resistant to Fas-mediated apoptosis in vitro. This lack of response may explain the selective decrease in apoptosis in EAF.
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    Different induction of adaptive response to ionizing radiation in normal and neoplastic cells (1999)
    Springer
    Cell biology and toxicology 15 (1999), S. 111-119 
    Details
    ISSN: 1573-6822
    Keywords: adaptive response ; apoptosis ; low-dose radiation ; neoplastic cells ; normal cells
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Since the beneficial effects of low-dose radiation (0.01 Gy) are usually observed in normal cells, we investigated whether the adaptive response was induced by low-dose radiation in neoplastic cells of different origin as well as in normal cells. Cell lines used in this experiment were as follows: mouse lymphocytes (NL); L929 cells established from mouse connective tissue; primary mouse keratinocytes (PK); line 308 from mouse papilloma; X-ray sensitive lymphoma cells, L5178Y-S and EL-4 cells from mouse lymphoma. The adaptive response was determined by cell survival and apoptosis. The involvement of apoptosis in the adaptive response was examined by ELISA and TUNEL assay. Adaptive response was induced by pretreatment with low-dose radiation of 0.01 Gy in normal cells such as NL, L929, and PK, but not in L5178Y-S, EL-4, and line 308 cells. In addition, the reduction of apoptosis by pretreatment with low-dose radiation was observed in NL, L929, and PK, but not in L5178Y-S, EL-4, and line 308 cells. These results suggested that the adaptive response could be induced by pretreatment with low-dose radiation and the phenomena were observed in normal cells, not in neoplastic cells. In addition, pretreatment with low-dose radiation reduced apoptosis, suggesting that an anti-apoptotic pathway may be involved in the adaptive response.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1007525531145
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  • 94
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    Electronic Resource
    A reappraisal of the role of Zn2+ in TGF-β1-induced apoptosis in primary hepatocytes (1999)
    Springer
    Cell biology and toxicology 15 (1999), S. 381-387 
    Details
    ISSN: 1573-6822
    Keywords: apoptosis ; hepatocytes ; in situ end-labeling ; TGF-β1 ; Zn2+
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract There is now a wealth of information regarding the apoptotic mode of cell death and its importance in toxicological studies in many mammalian organs including the liver. In this study, we investigated the modulatory effects of the heavy metal Zn2+ on transforming growth factor-β1 (TGF-β1)-induced apoptosis in primary rat hepatocytes. Apoptosis induced by TGF-β1 (1 ng/ml) in hepatocytes was accompanied by nuclear condensation as assessed morphologically by staining with Hoechst 33258 and DNA cleavage as detected biochemically by in situ end-labeling, field inversion and conventional gel electrophoresis. Pretreatment with 100 μmol/L Zn2+ abrogated the nuclear condensation, in situ end-labeling, and DNA laddering in TGF-β1-treated hepatocytes. Surprisingly, Zn2+ did not inhibit the formation of high-molecular-weight DNA fragments (30–50 kbp to 250–300 kbp). These data provide evidence that Zn2+ exerts its effects on the endonucleases that act downstream in the execution phase of TGF-β1-induced apoptosis in hepatocytes.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1007606016901
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  • 95
    Electronic Resource
    Electronic Resource
    A Novel Podophyllotoxin-Derived Compound GL331 Is More Potent than Its Congener VP-16 in Killing Refractory Cancer Cells (1999)
    Springer
    Pharmaceutical research 16 (1999), S. 997-1002 
    Details
    ISSN: 1573-904X
    Keywords: GL331 ; VP-16 ; apoptosis ; cytotoxicity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Purpose. GL331 is a new homolog of VP-16, and has demonstrated more efficacious anti-cancer activity in both the in vitro and in vivo lymphoma systems. To extensively explore GL331's clinical value, we furthermore evaluate the cytotoxicity and apoptosis-inducing activity of GL331 in several human cell lines from cancers that are not normally treated with VP-16. Methods. By MTT and clonogenic survival assays, the cytotoxicities of GL331 and VP-16 were evaluated in a variety of cell lines including nasopharyngeal, hepatocellular, gastric, colon, cervical, and neuro-blastoma cancer types. Western blot analysis was performed to detect the MDR-1 level in these cell lines. By Annexin V-staining flow cytometry and detection of DNA ladders, the apoptosis-inducing activities of GL331 and VP-16 were also evaluated. Results. GL331 showed more efficacy than its congener VP-16 in killing cancer cells. The estimated ID50 of GL331 were 2.5 to 17-fold lower than those of VP-16. GL331 possessed more cell-killing activity even in MDR-1-overexpressing cell lines such as HCC36 and SW620. Its higher cytotoxicity could be attributed by the elevated ability to induce apoptotic cell death. Conclusions. GL331's overriding drug resistance and higher cancer cell-killing activity suggest its superiority in clinical cancer therapy.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1018971313256
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  • 96
    Electronic Resource
    Electronic Resource
    Effects of Arbekacin and Vancomycin on Release of Lactate Dehydrogenase and Fragmentation of DNA in LLC-PK1 Kidney Epithelial Cells (1999)
    Springer
    Pharmaceutical research 16 (1999), S. 1132-1135 
    Details
    ISSN: 1573-904X
    Keywords: arbekacin ; vancomycin ; cisplatin ; apoptosis ; toxicity ; LLC-PK1 cells
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1011919306412
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  • 97
    Electronic Resource
    Electronic Resource
    New antitumor leads from a peptidomimetic library (1999)
    Springer
    International journal of peptide research and therapeutics 6 (1999), S. 325-333 
    Details
    ISSN: 1573-3904
    Keywords: antiproliferative effect ; apoptosis ; combinatorial library ; isosteric structures ; oxaniloyl hydrazides ; peptidomimetics ; substrate-binding site ; tyrosine kinase inhibition
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract A parallel combinatorial library of over 1600 compounds has been designed and synthesized for the development of new potential peptidomimetic protein tyrosine kinase (PTK) inhibitor leads. These peptidomimetic molecules are aimed at intervening with the substrate binding site of the pp60c-src enzyme. The new structures were based on known PTK inhibitors with at least two variously substituted aromatic moieties attached by spacer groups of different length and flexibility. Eleven bis-aryl-type inhibitory compounds were found in the range of 18–100 μM IC50 concentrations from combinations of 12 different substituents. Molecular modeling of the active compounds showed a characteristic distance of 12–14 Å between the farthest sp2 carbon atoms of the two aromatic rings. Conformational analysis of several peptide substrates recently found for pp60c-src PTK showed that the energy-minimized conformers had the same distance between the two aromatic moieties. Several compounds in the library not only showed remarkable PTK inhibitory activity but also a significant apoptosis-inducing effect on HT-29 human colon tumor cells.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1008994116275
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  • 98
    Electronic Resource
    Electronic Resource
    New antitumor leads from a peptidomimetic library (1999)
    Springer
    International journal of peptide research and therapeutics 6 (1999), S. 325-333 
    Details
    ISSN: 1573-3904
    Keywords: antiproliferative effect ; apoptosis ; combinatorial library ; isosteric structures ; oxaniloyl hydrazides ; peptidomimetics ; substrate-binding site ; tyrosine kinase inhibition
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary A parallel combinatorial library of over 1600 compounds has been designed and synthesized for the development of new potential peptidomimetic protein tyrosine kinase (PTK) inhibitor leads. These peptidomimetic molecules are aimed at intervening with the substrate binding site of the pp60c−src enzyme. The new structures were based on kown PTK inhibtors with at least two variously substituted aromatic moieties attached by spacer groups of different length and flexibility. Eleven bis-aryl-type inhibitory compounds were found in the range of 18–100 μM IC50 concentrations from combinations of 12 different substituents. Molecular modeling of the active compounds showed a characteristic distance of 12–14 Å between the farthest sp2 carbon atoms of the two aromatic rings. Conformational analysis of several peptide substrates recently found for pp60c−src PTK showed that the energyminimized conformers had the same distance between the two aromatic moieties. Several compounds in the library not only showed remarkable PTK inhibitory activity but also a significant apoptosis-inducing effect on HT-29 human colon tumor cells.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02443428
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  • 99
    Electronic Resource
    Electronic Resource
    Effect of methimazole on thyroid follicular structure in rats (1999)
    Springer
    Bulletin of experimental biology and medicine 127 (1999), S. 429-432 
    Details
    ISSN: 1573-8221
    Keywords: folliculogenesis ; follicle elimination ; apoptosis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Methimazole enhances blood circulation in the thyroid gland, thus stimulating folliculogenesis. Spasm of blood capillaries contacting with follicles non-adjacent to proliferating follicles leads to blood redistribution, apoptosis of the thyroid epithelium, destruction of the follicular wall, and elimination of the follicle.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02433401
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  • 100
    Electronic Resource
    Electronic Resource
    Polyfurancarbonic acid inhibits proliferation and induces apoptosis of cultured human T lymphocytesin vitro (1999)
    Springer
    Bulletin of experimental biology and medicine 127 (1999), S. 613-614 
    Details
    ISSN: 1573-8221
    Keywords: apoptosis ; proliferation ; lymphocytes ; polyfurancarbonic acid
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Polyfurancarbonic acid dose-dependently suppresses proliferation and induces apoptosis of human peripheral blood T lymphocytesin vitro. This finding indicates its possible involvement in the pathogenesis of lymphopenia during chronic renal failure.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02433293
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