- Type of paper
: Paper in journal
Title: EPR evidence for the oxidation-induced formation of
negatively chargedspecies on the low-density lipoprotein surface
- Authors:
- Brnjas-Kraljević, Jasminka (5663)
- Pifat, Margareta (37174)
- Herak, Janko (234)
- Jurgens, G. (2345)
Journal: Free Rad.Res.Comms.
Number: 5
ISSN: 8755-0199
Volume: 14
Year: 1991
Pages: from 307 to 313
Number of references: 21
Language: engleski
Summary:
Oxidation-induced increase of the net negative charge on LDL wasstudied by
electrophoretic mobility and electron paramagnetic re-sonance. The
negative-charge increase is associated not only withneutralisation of the
lysine residues of apo-B, but also with theexposition of the excessive
negatively charged residues on thelipoprotein surface. The accumulation of
the negatively chargedresidues is believed to be brought about by the
conformationalchange of apo-B, triggered by neutralization of lysines
andcleavage of peptide bonds. Alternatively, reactive oxygen speciescould
also convert histidine to aspatic acid and proline toglutamic acid.
Keywords: EPR, low-density lipoprotein, ion binding, lipoprotein oxidation, electrophoretic mobility
- Type of paper
: Paper in journal
Title: The effect of gallium arsenide laser irradiation and
partial hepatectomy on murine skin wound healing and lipoprotein
composition
- Authors:
- Žarković, Neven (2345)
- Saltzer, Branka (2345)
- Hrženjak, Maja (23445)
- Ilić, Zoran (2345)
- Pifat, Margareta (37174)
- Stipančić, Igor (1234)
- Vučković, Ivo (12345)
- Jurin, Mislav (1234)
Journal: Periodicum Biologorum
Number: 2
ISSN: 0031-5362
Volume: 93
Year: 1991
Pages: from 359 to 361
Number of references: 10
Language: engleski
- Type of paper
: Paper in journal
Title: Reinvestigation of the Oxidation Properties of Nitroxides
- Authors:
- Noethig-Laslo, Vesna (33526)
- Bobst, Albert M. (123)
Journal: Croatica Chemica Acta
Number: 1
ISSN: 0011-1643
Volume: 64
Year: 1991
Pages: from 1 to 8
Number of references: 25
Language: engleski
Summary: The rates of reduction of the two
amino-nitroxides,3-amino-2,2,5,5-tetramethylpyrrolidine-1-oxyl(I)
and4-amino-2,2,6,6-tetramethylpiperidine-1-oxyl (II) were compared.Reducing
agents, beta-mercaptoethanol and sodium ascorbate, werefreshly prepared in
the presence of nitrogen or air, in a bufferconsisting of 0.1 M
Na-cacodylate, 0.01 M NaCl, pH 7. Similarfunctions of the ESR signal
decrease with time were detected forI i II with both reducing agents under
nitrogen when the ratio ofnitroxide molarity versus reducing agent molarity
was kept thesame for a given set of experiments. However, a
significantdifference in the ESR signal decrease with time was
observedbetween I and II with ascorbate in the presence of air.Reproducible
time dependence of the ESR signal decay required theuse of freshly prepared
reducing solutions. Our results stronglysuggest that at least amino
substited five and sixmembered ringnitroxides oxidize electron donors at
the same rate. The apparentgreater stability of I versus II seems to be due
to the slowerreoxidation rate of the hydroxylamine of II as compared to
thehydroxylamine of I. Thus, under in vivo conditions, I and II willbecome
ESR silent at the same rate unles the tissue is not underanaerobic
conditions.
- Type of paper
: Paper in journal
Title: The Role of the Aluminosilicate Matrix in the
Gamma-irradiation Energy Transfer to the Oxalate Molecule
- Authors:
- Horvath, Laszlo (74311)
- Noethig-Laslo, Vesna (33526)
- Bilinski, Halka (12345)
Journal: Radiat. Phys. Chem.
Number: 2
ISSN: 0146-5724
Volume: 37
Year: 1991
Pages: from 325 to 329
Number of references: 14
Language: engleski
Summary: Three types of aluminosilicate matrices, prepared from
oxalatesolutions, were gamma-irradiated and investigated by
ESRspectroscopy. In the aluminosilicates with Al:Si= 1:1 that can
beconsidered as the end member of allophane series upongamma-irradiation at
room temperature in the presence of air, nostabile paramagnetic species
were formed, even if thealuminiumsilicate was precipitated in the presence
of oxalate. Onthe other hand, in the evacuated sample upon
gamma-irradiation atroom temperature a single line ESR spectrum at g=2 was
detectedthat was ascribed to oxalate redical, which was observed in
theother two types of aluminosilicastes even in the presence of air.Upon
gamma-irradiation at 77 K, in addition to the descriebedoxalate radical,
primary irradiation sites were observed andidentified as paramagnetic
centres derived from chlorides andhydrogen atoms. Radicals from chlorides
were observed in allsamples except in NaAl(OH)4(H4SiO4)2, the same as were
found inprotoimogolite allophane. Hydrogen atoms were found in
Al(OH)3H4SiO4 and NaAl(OH)4(H4SiO4)7. The results suggest that oxalateacts
as a trap for gamma-irradiation energy.
- Type of paper
: Paper in journal
Title: Paramagnetic Molecular Centers in the Gamma-irradiated
Novel Compound of Aluminium and Leucine, Al6(OH)10(leucine)2 x 5H20
- Authors:
- Noethig-Laslo, Vesna (33526)
- Himdan, Takialdin A. (1234)
- Bilinski, Halka (12345)
Journal: Radiat. Phys. Chem.
Number: 2
ISSN: 0146-5724
Volume: 37
Year: 1991
Pages: from 169 to 174
Number of references: 13
Language: engleski
Summary: A new microcrystalline compound Al6O4(OH)10(leucine)2x5H2O
ofpossible biological and biochemical interest has been preparedand
characterized by chemical analysis, i.r.spectrum, X-raydiffraction and
thermogravimetric analysis. It was exposed togamma-irradiation at 77 K and
at room temperature. Paramagneticspecies formed were studied by ESR
spectroscopy. The leucineradical has been identified which seems to be
stabilized in thealuminium leucine compound by crystalline water.
Coordinatedleucine molecule in aluminium hydroxide acts as a trap
forgamma-irradiation energy.
Keywords: aminoacids, ESR, gamma-irradiation, aluminates,
- Type of paper
: Paper in journal
Title: The influence of liver regeneration and tumor growth on
serum lipoprotein composition in mice
- Authors:
- Žarković, Neven (2345)
- Pifat, Margareta (37174)
- Saltzer, Branka (2345)
Journal: Periodicum Biologorum
Number: 1
ISSN: 0031-5362
Volume: 94
Year: 1992
Pages: from 53 to 58
Number of references: 23
Language: engleski
Summary: Since the proliferating cells catabolize intensively
sereumlipoproteins, especially low-density lipoproteins, the effects
oftumor growth and normal tissue regeneration on serum
lipoproteincomposition were analysed. The growth of melanoma
B16transplanted into the hind limb of mice was inhibited inlaparatomized
and even more in partially hepatectomized mice. Inlaparatomized and in
nonoperated tumor-bearing mice, the VLDLincreased and LDL fraction
decreased while the concentration ofthe HDL did not change significantly.
Thus, we concluded thattumor growth and surgucal treatment induced similar
changes inserum lipoprotein composition. Tumor growth inhibition
wasaccompained by the LDL concentrations equal to those determinedfor
normal healthy mice.
- Type of paper
: Paper in journal
Title: Electronic and ESR Spectra of Copper(II) Complexes with
N,N-dialkyl Aminoacids
- Authors:
- Paulić, Nevenka (35172)
- Noethig-Laslo, Vesna (33526)
- Simeon, Vladimir (43171)
Journal: Z.anorg.allg.Chem.
ISSN: 0044-2313
Volume: 613
Year: 1992
Pages: from 132 to 136
Number of references: 11
Language: engleski
Summary: Five N,N-dialkylamino acids were
synthesised:N,N-dimethylisoleucine (DMIL),
N,N-dimethyl-alloisoleucine(DMAIL), N,N-dimethlvaline(DMV),
N,N-diethilvaline(DEV), N,N-dimethyl-alanine (DEA) as well as their
complexes withcopper(II): Cu(DIML)2, Cu(DMAIL)2, Cu(DMV)2,
Cu(DMIL)(DMV),Cu(DEA)2 and Cu(DEV)2. UV/VIS spectra of the complexes
wererecorded in CH2Cl2 solutions and the ESR spectra in CN2Cl2, CD3ODand
D2O solutions. By applying the analysis of variance, ESRspectra were shown
to be influenced by the solvent andsubstituent differences, the former
effect being related to thedegree of covalency of the copper-ligand bonds.
The effect of theligands spatial configuration upon the ESR spectrum of
thecomplex was demonstrated and explained.
Keywords: amino-acidate complexes, Copper(II), ESR, N-alkylated amino acids
- Type of paper
: Paper in journal
Title: Dependence of the Co-ordination Sphere in
Bis(valinato)-copper(II) Complexes on Solvent and Alkylation at Nitrogen
- Authors:
- Noethig-Laslo, Vesna (33526)
- Paulić, Nevenka (35172)
Journal: J.Chem.Soc.Dalton Trans.
ISSN: 0300-9246
Year: 1992
Pages: from 2045 to 2047
Number of references: 16
Language: engleski
Summary: The N14 superhyperfine structure in the ESR spectra
ofbis(aminoacidato)copper(II) complexes(valine,alanine and
theirN,N-diethylated counterparts) was studied as a function of thesolvent
composition and temperature. The equlibrium between twocomponents,
presumably the cis and trans isomers, was found todepend on the solvent
dioxane:D2O ratio and on temperature, indifferent ways for the valine and
alanine complexes. Thusaddition of dioxane to water solvent, and an
increase intemperature from 293 K, stabilizes the valine
complexesanddestabilizes the alanine complexes. This suggests a
ligand-ligandinteraction between the two isopropyl residues of the
valinate.
- Type of paper
: Paper in journal
Title: Paramagnetic Molecular Centers in Gamma-irradiated
Precipitates in theSystem AlCl3-dl-alpha-valine-NaOH
- Authors:
- Noethig-Laslo, Vesna (33526)
- Himdan, Takialdin A. (1234)
- Bilinski, Halka (12345)
Journal: Radiation Research
ISSN: 0485-4611
Volume: 132
Year: 1992
Pages: from 1 to 6
Number of references: 23
Language: engleski
Summary: Formation and stability of paramagnetic molecular centers
werestudied in AlCl3-NaOH-dl-alpha-valine by ESR spectroscopy.
InAl3(OH)9(valine)x3H2O gamma-irradiated at room temperature thevaline(I)
radical was detected. The radical was formed byabstraction of a hydrogen
atom from the valine molecule coupledto the aluminium hydroxide matrix.
Stability of the radicaldepended critically on structural properties of the
aluminiumhydroxide matrix. In aluminium hydroxide with ratio (Al)/(valine)=
20, either no paramagnetic species were detected or a singletat g=2.008 of
1.8 mT linewidth was detected at room temperature.Primary paramagnetic
species in Al3(OH)9(Val)x3H2O are chlorideparamagnetic centers and the
primary neutral valine radical(II).It was formed by abstraction of the NH2
group from the valinemolecule. With warming, this radical was not
transformed toradical (I).
- Type of paper
: Paper in journal
Title: Aspartic Acid as a Trap for gamma-Radiation Energy in the
Amorphous Al5(OH)15(asp)3x3H2O
- Authors:
- Himdan, Takialdin A. (1234)
- Noethig-Laslo, Vesna (33526)
- Bilinski, Halka (12345)
Journal: Radiation Research
ISSN: 0485-8611
Volume: 131
Year: 1992
Pages: from 266 to 271
Number of references: 16
Language: engleski
Summary: Paramagnetic molecular centers produced by
gamma-irradiation at77 K and at room temperature in the novel
compoundAl5(OH)15(Asp)3 x 3H2O were studied by ESR spectroscopy. The gvalue
of 2.0034 and the lack of such lines in pure aluminiumhydroxide suggested
that all the paramagnetic centers observedare related to the aspatic acid
molecule. However, none of theparamagnetic centers gave an ESR spectrum
characteristic forgamma-irradiated pure aspatic acid powder. The influence
of theoxygen on the formation of the paramagnetic centers was noticed.The
extreme stability of the paramagnetic molecular centersformed in
Al5(OH)15(Asp)3 x3H2O suggests that aspatic acidcomplexed in aluminium
hydroxide is a good trap forgamma-radiation energy.
- Type of paper
: Paper in journal
Title: Paramagnetic Molecular Centers in the Gamma-irradiated
Precipitates Obtained in the System AlCl3-beta-alanine-NaOH
- Authors:
- Himdan, Takialdin A. (1234)
- Noethig-Laslo, Vesna (33526)
- Bilinski, Halka (12345)
Journal: Radiat. Phys. Chem.
Number: 3
ISSN: 0146-5724
Volume: 40
Year: 1992
Pages: from 225 to 231
Number of references: 10
Language: engleski
Summary: The presented results are the continuation of our work
onparamagnetic molecular centers in the model clay compounds. Hereit was
attempted to incorporate beta-alanine in the aluminiumhydroxide matrix. A
series of precipitates were prepared with thehighest ratio of
beta-alanine/Al = 0.22 obtained at pH=7. X-raydiffrection analysis revealed
in addition to amorphousprecipitates, microcristalline samples of four
different X-raypetterns in nine precipitates, indicating variations in
thestructure of aluminium hydroxide matrix with
incorporatedbeta-alanine.Selected samples were exposed to
gamma-irradiationat 77 K, and at room temperature in the presence and in
theabsence of air. In all the samples of amorphous structure nostable
paramagnetic centers were determined by ESR aftergamma-irradiation in air.
In all samples of microcristallinestructure similar stable paramagnetic
centers were determined byESR after gamma-irradiation in air and in
evacuated tubes. Theseparamagnetic centers that we were unable to identify
due tothe poor resolution of the lines in the ESR spectrum can be
mostprobably ascribed to structural defects introduced into thealuminium
hydroxide matrix by beta-alanine. In all amorphoussamples gamma-irradiated
in the absence of air, the radicalCH2CH2COOH formed by abstraction of amino
group from thebeta-alanine was determined by ESR. The radical was unstabile
inair. Thus in the absence of air beta-alanine may be consideredas a
storage site for the gamma-irradiation energy in theamorphous aluminium
hydroxides.
- Type of paper
: Paper in journal
Title: Chemical modification of low-density lipoprotein enhances
the number of binding sites for divalent cations
- Authors:
- Pifat, Margareta (37174)
- Brnjas-Kraljević, Jasminka (5663)
- Jurgens, G. (2345)
- Herak-Kramberger, Carol M.
- Herak, Janko (234)
Journal: Chemistry and Physics of Lipids
ISSN: 0009-3084
Volume: 63
Year: 1992
Pages: from 159 to 167
Number of references: 33
Language: engleski
Summary: The EPR technique with paramagnetic Mn(II) ions has been
used toprobe the negatively charged sites on the surface of
modifiedlow-density lipoprotein (LDL). LDL modified in five differentways
exhibited increased binding capacity for divalent cations.Enhanced binding
is caused by the increase in the number of"strong" binding sites. The
"strong" sites have been identifiedto be the aspartic acid and/or glutamic
acid residues and the"weak" sites are zwitter-ionic phospholipids. In
native LDL thenegative groups make "bonds" with positive lysyl residues,
thusstabilizing the structure. Any deprotonation or modification ofthe
lysine amino groups makes the LDL structure more loose andthe amino acid
carboxyl groups accessible to divalent cations.
Keywords: EPR, LDL, LDL modification, stabilization of structure, Mn(II) binding
- Type of paper
: Paper in journal
Title: A methodology for cluster analysis of citation histories
- Authors:
- Lužar, Vesna
- Dobrić, Vesna
- Maričić, Siniša
- Pifat, Margareta (37174)
- Spaventi, Jagoda
Journal: Quality & Quantity
Volume: 26
Year: 1992
Pages: from 337 to 365
Number of references: 20
Language: engleski
Summary: multydisciplinary (natural sciences) research institute
within"scientific periphery" were collected for the 11-year periodafter
10-year lapse since the publication years. All the paperswere grouped into
31 research topics, three of which had no suchlate citations at all. For
remaining 28 groups of papers threeindicators were defined; ALPHa, the
ratio of the number of paperswith citations, to the number of all papers of
the particularresearch topic, indicating thus an overall CITATION
EFFICACY;BETA, the ratio of the sum of all citation
, to the number of the cited papers, indicating CITATIONINTENSITY, and
GAMMA, expressing the CITATION LONGEVITY for agiven research topic as the
incidence of cited papers within the11-year citid period. In addidition,
three normalizedtransformation of the indicator BETA were
checked.Two-dimensional and three dimensional graphical
representationstogether with a pairwise correlation analysis served
aspreliminary guidance in the latter ststistical analyses by(a) Wards
Hierarchical Cluster Analysis and (b) Polar TaxonsAnalysis. Both of them
resulted in good agreement. Thus, the 28research topics were found to
belong to three clusters. Theircomposition varied slightly for the original
BETA and its threenormalized values. It was concluded that ALPHA is not a
redundantbut quite usful indicator, and that one of the
normalizedBETA-veriants appears most suitable for this kind of studies.
Inthe three-dimensional graphs the clusters may be related toscientific
merit as judged in a composite way by all the threeindicators. This is done
with regard to the diagonal joining theindicators maximal wth their minimal
values. The citationLONGRVITY (GAMMA) appears ti be most important. Cluster
stabilityteste showed fluctuations of few research topics, which wasrelated
to their specific features within the given researchsetting. It emerges on
the whole that the research merit of this scientific production is
determined neither by the journalsstatus the papers were published in, nor
by the authorsinstitutional status. Rather, it is the very scientific
qualityof individual papers within a given research topic that isdecisive
for the citation "survival".
- Type of paper
: Paper in journal
Title: The ESR characterization of molecular mobility in the
lipid surface layer of human serum lipoproteins
- Authors:
- Kveder-Ilakovac, Marina (113615)
- Pifat, Margareta (37174)
- Pečar, Slavko
- Schara, Milan
Journal: Chemistry and Physics of Lipids
ISSN: 0009-3084
Year: 1993
Pages: from 0 to 0
Number of references: 22
Language: engleski
Summary: Three different nitroxides were used to probe either the
headgroup (Tempil stearate) or acyl chain region (Spin labeledcholestane
(ChSl) and methyl ester of 5 doxyl palmitate(MeFASL(10.3))) of human plasma
LDL and VLDL. The ESR data werecompared with the stimulated spectra which
assume rapidanisotropic motion of nitroxide. The results indicate that in
thehead group region of both LDL and VLDL only the slowing down ofthe
rotational motion occured when temperature was lowered andthe whole region
showed up as a unique compartment. On the otherhand, the acyl chain region,
probed with MeFASL(10,3), behaved asone compartment at physiological
temperatures, while at lowertemperatures coexistance of fluid and
immobilized components wereobserved. The ESR spectra of lipoproteins
labeled with Cholestaneshowed even higher sensitivity to the mobility
constrains. Here,the LDL spectra revealed a drastic immobilization of ChSl
axialrotation already at physiological temperatures. The results ofthese
experiments were discussed in terms of core phasetransition and/or
lipid-protein interaction.
Keywords: ESR, LDL, VLDL, nitroxides, lipoproteins, simulation
- Type of paper
: Paper in journal
Title: Hydroxilamines as oxygen-sensitive procontrast agens for
in vivo magnetic resonance imaging
- Authors:
- Dem(ar, Slavko
- Kveder-Ilakovac, Marina (113615)
- Rugelj, S
- Blinc, A
- Šentjurc, Marjeta
- Pečar, Slavko
Journal: J.Mag. Res.
ISSN: 0022-2364
Volume: 95
Year: 1991
Pages: from 281 to 285
Number of references: 16
Language: engleski
- Type of paper
: Paper in journal
Title: Nitroxide radicals as model system for biotransformations
of radicals in tissues
- Authors:
- Kveder-Ilakovac, Marina (113615)
- Pečar, Slavko
- Nemec, M
- Schara, Milan
Journal: Acta Pharmaceutica Jugoslavica
ISSN: 0001-6667
Volume: 41
Year: 1991
Pages: from 391 to 400
Language: engleski
Summary: Nitroxide free radicals were used as a model system to
study thebiotransformation of free radicals in rat liver tissue samples.The
results indicate that in aerobic conditions iron ions canswitch the
commonly observed reduction of nitroxides into theprevalence of reoxidation
processes. These observations werecomfirmed by the experiments in aqueous
solutions withhomogeneous mixtures of reactants. The conclusions from
thisstudy confirm the general idea of oxygen toxicity and give aninsight in
the possible mechanisms sustaining radical vitality invivo in the presence
of iron ions or their complexes.
Keywords: biotransfornation, nitroxides, tissue, iron ions, ESR
- Type of paper
: Summary in proceedings
Title:
- Authors:
- Noethig-Laslo, Vesna (33526)
- Paulić, Nevenka (35172)
Proceedings title: 6th Chianti Workshop on Magnetic Resonance, Nuclear and Electron Relaxation
Language: engleski
Place: Pisa, Italija
Year: 1995
Meeting: 6th Chianti Workshop on Magnetic Resonance, Nuclear and Electron Relaxation
Held: from 05/27/95 to 06/02/95
- Type of paper
: Summary in proceedings
Title:
- Authors:
- Brnjas-Kraljević, Jasminka (5663)
Proceedings title: International Conference on Molecular Biophysics
Language: engleski
Place: Hunfeld, Njemačka
Year: 1993
Meeting: International Conference on Molecular Biophysics
Held: from 05/13/93 to 05/15/93
- Type of paper
: Summary in proceedings
Title:
- Authors:
- Brnjas-Kraljević, Jasminka (5663)
- Knipping, G.
- Jurgens, G. (2345)
Proceedings title: 11th International Biophysics Congress
Place: Budimpešta, Mađarska
Year: 1993
Meeting: 11th International Biophysics Congress
Held: from 07/25/93 to 07/30/93
- Type of paper
: Summary in proceedings
Title:
- Authors:
- Kveder-Ilakovac, Marina (113615)
- Pifat, Margareta (37174)
- Pečar, Slavko
- Schara, Milan
Proceedings title: Fifth International Summer School on Biophysics
Language: engleski
Place: Zagreb
Year: 1994
Pages: from 83
Meeting: 5th International Summer School on Biophysics
Held: from 09/18/94 to 09/29/94
- Type of paper
: Summary in proceedings
Title:
- Authors:
- Mesagarzadeh, A.
- Lassen, D.
- Kveder-Ilakovac, Marina (113615)
- Specht, B.
- Lezius, A.
- Spener, F.
- Ruterjans, H.
Proceedings title: The Use of Stable Isotopes in NMR Studies of Protein Structure, Dynamics and Fun
Language: engleski
Place: Pariz, Francuska
Year: 1994
Meeting: Utilisation des Isotopes Stables dans l'Etude des Proteines par RMN: Structure, Dynamique et Fonction
Held: from 03/21/94 to 03/23/94
- Type of paper
: Invited lecture
Title:
- Authors:
- Noethig-Laslo, Vesna (33526)
- Paulić, Nevenka (35172)
Institution: EPR in Living Systems and Condensed Matter
Year: 1995
- Type of paper
: Invited lecture
Title:
Institution: Slovensko kemijsko društvo
Year: 1995
- Type of paper
: Invited lecture
Title:
Institution: Hrvatsko biofizičko društvo
Year: 1994
