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Impact of N-2-mercaptopropionylglycine (MPG) and simvastatin on exercise-induced cardiac adaptationsNelson, Matthew Jay 20 September 2012 (has links)
Experiments were conducted to investigate the role of free radicals in exercise induced cardiac adaptations and to determine if statin administration would adversely affect cardiac adaptations to exercise. In the first experiment myocardial antioxidant enzymes, cardiac function and cardiac hypertrophy were assessed following a chronic exercise protocol previously used by our lab. MPG effectively reduced myocardial oxidative stress and activation of the signaling proteins Akt and S6 following an exercise bout. Skeletal muscle mitochondria content increased to similar levels in E and E+MPG. Similar increases (P<0.05) in both exercised groups were observed for heart wt and heart wt to body wt ratio. Cardiac function at the high workload improved in E vs S as indicated by higher (P<0.05) peak systolic pressure (SP), cardiac output (CO), coronary flow, COxSP and mechanical efficiency (COxSP/VO2). MPG prevented these exercise-induced functional improvements. This study provides evidence that free radicals do not play a role in the development of exercise-induced cardiac hypertrophy, however, they are involved in functional cardiac adaptations, which may be mediated through the PI3K/Akt pathway. In the second experiment a similar exercise protocol was used to determine if statins which have been shown to prevent pathological forms of cardiac hypertrophy, would be detrimental to exercise induced cardiac adaptations. In addition to the sedentary and exercise groups sedentary+statin and exercise+statin groups were assessed. Hearts were isolated and perfused and assessed for function at low and high workloads. Exercise treatment resulted in cardiac hypertrophy in absolute and relative terms to a similar extent in statin-treated and untreated exercised rats. Additionally it resulted in significant functional increases for SP, CO, COxSP, VO₂, and EFF in both exercised groups. In conclusion, these studies provide evidence that exercise in the cold is a valid model for physiological cardiac hypertrophy and that pathological and physiological cardiac hypertrophy signal through different pathways due to the fact that two well established treatments (mpg and statins) that prevent pathological cardiac hypertrophy did not affect exercise induced cardiac hypertrophy. / text
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Measurement of free radicals and their effects on human spermatozoaLampiao, Fanuel 03 1900 (has links)
Thesis (MSCMedSc (Biomedical Sciences. Medical Physiology))--University of Stellenbosch, 2006. / In this study, we presented data on the role of free radicals in human spermatozoa, particularly in the context of centrifugation and the potential development of defective sperm function. In order to achieve this, methods were developed to directly measure intracellular free radicals in human sperm and the effects of exogenously applied free radicals on sperm function were established. The role of brief and prolonged centrifugation and the associated generation of free radicals was also investigated.
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Evaluation of antioxidant and free radical scavenging activities of honeybush tea (Cyclopia)Hubbe, Michelle E. (Michelle Elzabet) 12 1900 (has links)
Thesis (MSc)--Stellenbosch University, 2000. / ENGLISH ABSTRACT:
Please refer to fulltext for abstract / AFRIKAANSE OPSOMMING:
Sien asb volteks vir opsomming
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Tagged polymers as recognition agentsRamiah, Vernon 12 1900 (has links)
Thesis (MSc)--University of Stellenbosch, 2005. / ENGLISH ABSTRACT: Chemical and molecular tagging agents have illustrated their diversity in a number of
different applications. One of the most significant applications includes the use of chemical
tagging agents for product registration in industry. Industrial enterprises producing good
products need to ensure product authenticity to prevent duplication through piracy and
unscrupulous industrialists. Fluorescent probes are chemical compounds that satisfy most
of the technical and commercial aspects that are required to be excellent tagging agents.
They are generally quick to synthesize, do not affect the product integrity, display little or
no impact on the uses of the product or the environment and they can be identified by
relatively simple detection procedures. The aim of the present study was to synthesize
fluorescent polymers as tagging agents for the paint industry.
7-Hydroxy-2H-chromen-2-one (A1) and 7-hydroxy-4-methyl-2H-chromen-2-one (B1),
commercially available fluorescent hydroxyl compounds, were selected as the starting
materials. An esterification reaction resulted in the production of 2-oxo-2H-chromen-7-yl
acrylate (A2) and 4-methyl-2-oxo-2H-chromen-7-yl acrylate (B2), which are acrylic-type
monomers that were required for polymerisation. Studies showed that fluorescence was
maintained during the esterification.
Copolymers poly(MMA-co-A2), poly(MMA-co-B2), poly(BA-co-A2) and poly(BA-co-B2),
synthesized via homogeneous free radical initiated copolymerisation, revealed how
copolymer compositions were affected by the feed compositions and the pattern of
monomer incorporation over time. This was investigated by following individual monomer
consumption rates by 1H-NMR spectroscopy. Fluorescence studies revealed that the
fluorescence behaviour of A2 and B2 was maintained during the copolymerisation.
Latex particles, with fluorescent behaviour, were synthesized via in situ miniemulsion
polymerisation. High molecular weight copolymers with monodisperse particle sizes (nm
range) were obtained. A bench-top UV lamp and UV-reflectance studies confirmed the fact that fluorescent latex
particles can be identified and quantified respectively, when dispersed in paints that are
either free of titanium dioxide or paints that contain titanium dioxide. / AFRIKAANSE OPSOMMING: Die diversiteit van chemiese en molekulêre merkers in ‘n verskeidenheid van toepassings is
al telkemale geïllustreer. Een van die mees belangrike toepassings in die industrie is die
gebruik van chemiese merkers vir produkregistrasie. Industrieë wat goeie produkte verskaf
moet die egtheid van hul produkte kan verseker deur duplikasie via nadruk (Eng: piracy)
deur ander te voorkom. Fluoresserende merkers is chemiese stowwe wat aan die meeste
van die tegniese en kommersiële vereistes voldoen om as uitstekende merkers te dien. Die
sintese van die merkers is gewoonlik nie tydrowend nie, beïnvloed nie die integriteit van
die produk nie, het min of geen impak op die gebruike van die produk of die omgewing en
kan deur relatief eenvoudige prosedures bepaal word. Die doel van hierdie studie was die
sintese van fluoresserendepolimere om as merkers in die verfindustrie te dien.
7-Hidroksie-2H-chromen-2-oon (A1) en 7-hidroksie-4-metiel-2H-chromen-2-oon (B1),
fluoresserende hidroksielverbindings wat kommersieël beskikbaar is, is gekies as
uitgangstowwe vir die bereiding van die merkers in hierdie studie. ‘n Esterifikasie-reaksie
het gelei tot die produksie van 2-okso-2H-chromen-7-ielakrilaat (A2) en 4-metiel-2-okso-
2H-chromen-7-ielakrilaat (B2). Hierdie produkte is tipiese akrilaat-tipe monomere wat
benodig word vir polimerisasie. Ondersoeke het getoon dat fluoressensie behoue tydens
esterifikasie gebly het.
Die kopolimere poli(MMA-ko-A2), poli(MMA-ko-B2), poli(BA-ko-A2) en poli(BA-ko-B2)
is deur homogene vry-radikaal-geïnisieerde kopolimerisasie gesintetiseer. Daar is vasgestel
hoe die kopolimeersamestelling geaffekteer is deur die samestelling van die reagense (Eng:
feed composition) en die patroon van monomeer inkorporasie met tyd. Dit was ondersoek
deur die tempo van verbruik van die individuele monomere d.m.v. 1H-KMR spektroskopie
te bepaal. Daar is verder vasgestel dat die fluoressensie van A2 en B2 gedurende
kopolimerisasie behoue gebly het. Latekspartikels, met fluoressensie gedrag, is via in-situ
mini-emulsie-polimerisasie gesintetiseer. Hoë molekulêre massa kopolimere met
monodisperse partikelgroottes (in die order van nanometers) is verkry. Deur van ‘n UV-lamp en UV-refleksie studies gebruik te maak is daar bepaal dat
fluoresserende latekspartikels in polimere, in verf - wat of titaniumdioksied bevat of geen
titaniumdioksied bevat nie -, beide geïdentifiseer and gekwantifiseer kan word.
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Mechanistic studies of reversible addition-fragmentation chain transfer mediated polymerizationCalitz, Francois Malan 03 1900 (has links)
Thesis (PhD)--Stellenbosch University, 2004. / ENGLISH ABSTRACT: To comply with the ever growing demands for materials with better properties and complex architectures,
polymer chemistry has resorted to the use of living free radical polymerization techniques. Despite the structural
control some of these techniques offer, major disadvantages do exist. For example, most require ultra-pure
reagents, hence only a small fraction of the monomers used in industry can be polymerized in this way. This
rendered these new living techniques less advantageous from a commercial point of view. Recently, a
revolutionary new living free radical process, namely the reversible addition-fragmentation chain transfer
process, or RAFT process, was developed that combines the control over the polymer produced with the
robustness and versatility of a free radical process.
However, the RAFT process is not without its problems. In some dithioester mediated polymerizations,
significant inhibition and rate retardation effects have been observed. Two main opposing opinions have been
proposed in recent literature to explain these phenomena observed. The main point of difference between these
two groups is the fate of the formed intermediate RAFT radicals, i.e., slow fragmentation of the formed
intermediate radicals together with possible reversible intermediate RAFT radical termination, or fast
fragmentation of the formed intermediate radicals together with possible irreversible intermediate RAFT radical
termination. Between these opposing two groups, there is a difference of six orders of magnitude for the rate of
fragmentation of the formed intermediate RAFT radicals.
The work presented in this thesis is an attempt to clarify some of the mysteries, i.e., inhibition and rate
retardation observed in some RAFT polymerizations. Experimental evidence to support or contradict the
theories of the above mentioned two opposing groups was investigated.
The concentration-time evolution of the intermediate radical concentration (cy), for styrene and butyl acrylate
polymerizations mediated by cumyl dithiobenzoate (COB) at 70°C and 90 °C, was followed via in situ electron
spin resonance spectroscopy (ESR). The concentration-time evolution profiles observed were ascribed to the
formation of very short chains during the early stages of the reaction. It was also found that the RAFT process is
not particularly sensitive to oxygen. The intermediate and propagating radical (cp) concentrations (and their
ratio) for the cumyl dithiobenzoate mediated styrene polymerizations were examined by ESR spectroscopy and
kinetics. The system showed strong chain length effects in kinetics, assuming all chains were of similar number
average molar mass (Mn). However, unusual behavior with respect to existing mechanistic knowledge was
observed in other aspects of the system. The central equilibrium "constant" (Keq) was found to be dependent on
both temperature and initial reactant concentrations. The observed intermediate radical concentrations were not
consistent with predictions based on existing literature models. It was also found that the time dependence of
the intermediate radical concentration varies significantly with the type of RAFT agent used. Unexpectedly, intermediate radicals were detected at very long reaction times in the virtual absence of initiator, enhancing the
belief of possible reversible termination reactions involving the intermediate radicals. An extra radical (nonpropagating
or intermediate) species was observed (via ESR spectroscopy) to form during some reactions. Its
concentration increased with time.
The combination of data from several analytical techniques provided evidence for the formation of dead chains
by the termination of intermediate radicals in the free radical polymerization of styrene, mediated by a cumyl
dithiobenzoate RAFT agent, at 84°C. Experiments done focused on the early stages of the reactions, targeting
very low final number average molar mass values, with high initiator concentrations. The formation of these
terminated chains did not occur to a significant extent until a large fraction of the chains reached a degree of
polymerization greater than unity. This corresponded to the occurrence of a maximum in intermediate radical
concentration.
In situ 1H nuclear magnetic resonance (NMR) and electron spin resonance spectroscopy was used to directly
investigate the processes that occur during the early stages (typically the first few monomer addition steps) of an
AIBN-initiated reversible addition fragmentation chain transfer polymerization of styrene, in the presence of a
cyanoisopropyl dithiobenzoate and cumyl dithiobenzoate RAFT agent, at 70°C and 84 °C respectively. 1H NMR
spectroscopy allowed the investigation of the change in concentration of important dithiobenzoate species as a
function of time. Identification and concentrations of the radicals present in the system could be inferred from
corresponding ESR spectroscopy data. An apparent "inhibition" effect was observed in both the cyanoisopropyl
and cumyl dithiobenzoate mediated polymerizations. This effect could be reduced by increasing the reaction
temperature to 84 °C. However, the use of cumyl dithiobenzoate as RAFT agent prolonged this effect. This
apparent "inhibition" effect was attributed to selective fragmentation of the formed intermediate radicals during
the early stages of the reaction, and to different propagation rate coefficients (kp) of the resulting (different)
radicals. A change in the equilibrium coefficient for the systems investigated was ascribed to possible
progressively decreasing addition and fragmentation rate coefficients of propagating and intermediate radicals
formed during the reaction. The increase in intermediate radical concentration, and thus possible intermediate
radical termination, was shown to also be a probable cause of the rate retardation observed in the RAFT
mediated systems investigated.
To conclude, probable causes of the observed inhibition and rate retardation in some dithiobenzoate mediated
systems were investigated. It was found that intermediate RAFT radical termination does occurs, albeit
reversibly or irreversibly. A maximum in the intermediate radical concentration, and thus possible intermediate
radical termination, was seen to occur during the observed rate retardation. An apparent inhibition effect
observed was ascribed to a possible change in termination kinetics, the formation of terminated intermediate
radical products and a rapidly changing kp of the propagating radicals. / AFRIKAANSE OPSOMMING: Om te voldoen aan die ewig groeiende aanvraag vir materiale met beter eienskappe en komplekse
samestellings, is in die polimeerchemie lewende vry-radikaal polimerisasietegnieke ontwikkel. Ten spyte van die
feit dat party van die polimerisasie tegnieke die strukuur van die gevormende polimere kan beheer, bestaan daar
tog nadele. Die meeste polimerisasie tegnieke benodig ultra suiwer reagense, dus kan net 'n klein fraksie van
die monomere wat deur die industrie gebruik word op so 'n manier gepolimeriseer word. Dus, vanuit 'n
komersieële oogpunt, is die nuwe lewende polimerisasietegnieke minder voordelig. Onlangs is 'n revolusionere
nuwe lewende vry-radikaal polimerisasieproses, naamlike die RAFT-(eng. reversible addition-fragmentation
chain transfer process) proses ontwikkel, wat die beheer oor die geproduseerde polimere, kombineer met die
robuustheid en veelsydigheid van 'n vry-radikaalproses.
Die RAFT proses is egter nie sonder probleme nie. Beduidende inhibisie en vertraging van die polimerisasie
tempo is in sommige dithioester-bemiddelde polimerisasies opgemerk. Daar is hoofsaaklik twee opponerende
opinies oor die redes vir die inhibisie en vertragings effekte. Die grootste verskil tussen die twee groepe lê in die
lot van die gevormde intermediêre radikaal, m.a.w. stadige fragmentasie van die gevormende intermediêre
radikale tesame met moontlike onveranderlike intermediêre radikaalterminasie, of vinnige fragmentasie tesame
met moontlike omkeerbare intermediêre radikaalterminasie. Tussen die twee groepe, is daar 'n verskil van ses
ordegrotes vir die groote van die tempo van fragmentasie van die gevormende intermediêre radikaal.
Die werk wat in die tesis weergee word, is 'n poging om sommige van die geheime van die RAFT proses, m.a.w.
inhibisie en vertraging van die polimerisasietempo, op te los. Die ondersoek was gerig op eksperimetele bewyse
om die teorieë van die twee opponerede groepe of te bevestig of teen te spreek.
Die konsentrasie tyd-verandering van die intermediêre radikaal konsentrasie vir stireen- en
butielakrilaatpolimerisasie, bemiddeled deur CDB (eng cumyl dithiobenzoate) by 70 oe and 90 oe, is gevolg deur
middel van in situ (lat. vir in die oorspronklike plek, m.a.w. binne-in die ESR masjien) elektronspin-resonans
(ESR) spektroskopie. Die vorm van die konsentrasie tyd-profiele is toegeskryf aan die vorming van baie kort
polimeerkettings gedurende die vroeë reaksietye. Dit is ook bepaal dat die RAFT-proses nie besonder sensitief
was vir suurstof nie. Die intermediêre en die propagerende radikaalkonsentrasie (en hulle verhouding) vir die
CDB bemiddelde stireen polimerisasies, is bepaal deur middel van elektronspin-resonans spektroskopie en die
kinetika van die sisteem. Die kinetika van die sisteem toon 'n sterk afhanklikheid teenoor die lengte van die
polimeerkettings, as aanvaar word dat al die kettings dieselfde numeriese gemiddelde molêre massa het. Des
nieteenstaande, is egter onverwagte gedrag in ander aspekte van die sisteem opgemerk. Dit was ook gevind
dat die sentrale ewewigs-"konstante" (Keq) afhanklik was van die temperatuur en die oorspronklike reaktant
konsentrasie. Die bepaalde intermediêre radikaalkonsentrasie het verskil van voorspelde waardes gebaseer op literatuur modelle. Dit is ook gevind dat die intermediêre radikaalkonsentrasie afhanklik is van die tipe RAFT
agent wat in die polimerisasie reaksies gebruik word. Intermediêre radikale is onverwags gevind na baie lang
reaksietye, wanner verwag is dat die konsentrasie van die afsetter, en dus ook die intermediêre radikale, baie
klein sou wees. Dit het die verwagting dat omkeerbare intermediêre radikaalterminasie kan plaasving, versterk.
'n Ekstra radikale spesie, wat gedurende die reaksie vorm en waarvan die konsentrasie groter word met tyd, is
ook deur ESR-spektroskopie geidentifiseer.
'n Kombinasie van verskillende skeikundige tegnieke is gebruik om bewyse te kry vir die vorming van dooie
kettings wat ontstaan deur middel van intermediêre radikale terminasiereaksies, in die vry-radikaalpolimerisasie
van stireen, wat deur 'n CDB RAFT-agent bemiddeled word by 84°C. Eksperimente is gedoen om die reaksie
tydens vroeë reaksietye te ondersoek. Baie hoë afsetter konsentrasies is ook gebruik, wat tot uiters lae
numeriese gemiddelde molêre massas van die polimeerkettings gelei het. Beduidende konsentrasies van die
dooie kettings is eers gevind nadat 'n graad van polimerisasie van groter as een bereik is. Dit het ooreengestem
met 'n maksimum in die konsentrasie van die intermediêre radikale.
In situ 1H kern magnetiese-resonans (KMR) en electronspin-resonans spektroskopie was gebruik om 'n RAFT
proses, wat gedurende die vroeë reaksie tye (tipies gedurende die eerste paar monomeer toevoegingstappe) te
bestudeer, wat deur AIBN (eng azo bis(isobutyronitrile)) afgeset word en bestaan uit stireen en CIDB (eng
cyanoisopropyl dithiobenzoate) en CDB RAFT agente onderskeidelik, en by 70°C and 84 °C reageer. 1H KMRspektroskopie
was gebruik om die veranderinge in die konsentrasie van die belangrike spesies te bepaal. Die
identifikasie en konsentrasie van die radikale kon bepaal word deur middel van ESR data. 'n Skynbare
'inhibisie-effek' is waargeneem in die reaksies wat bemiddeled word deur CIDB en CDB. Die effek is verminder
toe die reaksietemperatuur verhoog is na 84°C. Die gebruik van CDB as RAFT agent het egter die effek
vergroot. Die skynbare 'inhibisie effek' was toegeskryf aan die selektiewe fragmentasie van die intermediêre
radikale gedurende die vroeë reaksietye, en aan verskillende propagasie tempokoëffisiënte (kp) van die
verskillende radikale. Die veranderlike sentrale ewewigskoëffisiënte is toegeskryf aan die toevoegings en
fragmentasie tempokoëffisiënte van die propagerende en intermediêre radikale wat toenemend afneem. Die is
ook getoon dat die toename in die konsentrasie van die intermediêre radikale en dus moontlike intermediêre
radikale terminasie, 'n oorsaak kan wees van die vertraging van die polimerisasietempo in die RAFT-bemiddelde
reaksies.
Ter samevatting, die waarskynlike oorsake vir inhibisie en die polimerisasietempo vertraging opgemerk in sekere
dithiobenzoaat-bemiddelde sisteme, is ondersoek. Dit was gevind dat intermediêre radikaalterminasie wel kan
gebeur, of dit nou omkeerbaar of onveranderlik gebeur. 'n Maksimum in die konsentrasie van die intermediêre
radikale, en dus moontlike intermediêre radikaalterminasie, het voorgekom tesame met 'n vertraging in die
polimerisasietempo. Die skynbare inhibisie-effek wat opgemerk was kan toegeskryf word aan 'n moontlike verandering in die terminasie kinetika, die formasie van getermineerde intermediêre radikale en 'n vinnig
veranderende propagasie tempokoëffisiënt.
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Analysis of free radical characteristics in biological systems based on EPR spectroscopy, employing blind source separation techniquesRen, Jiyun., 任紀韞. January 2006 (has links)
published_or_final_version / abstract / Electrical and Electronic Engineering / Doctoral / Doctor of Philosophy
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Exercise and DNA damage and repair in middle aged men / Matthew Andrew AikmanAikman, Matthew Andrew January 2007 (has links)
Regular physical activity (PA) leads to an increased quality of life by means of certain
physiological adaptations. Regular PA is beneficial to the human body and its functionality,
including the physiological, biochemical and even psychological modalities. During PA an
increased burden is placed on all physiological mechanisms due to the increased energy demand,
resulting in an adaptation of the physiological systems. Currently the biochemical mechanisms
by which these adaptations occur are not well understood or defined.
During the flow of electrons through the electron transport chain in the mitochondria free
radicals and reactive oxygen species (ROS) are produced. PA results in increased ROS
production. The relationship of different exercise intensities and ROS production with resulting
DNA damage is unclear. These free radicals and ROS disturb the pro-oxidant anti-oxidant
balance resulting in oxidative stress. When this balance is disturbed oxidative stress could lead to
potential oxidative damage, Oxidative damage occurs in lipid, protein and nucleic acid
macromolecules. ROS can attack DNA bases or deoxyribose residues to produce damaged bases
and/or single and double strand breaks. When the DNA is regarded and the damages are
replicated it could cause mutations or apoptosis, affecting the cell function and physiology.
The purpose of this study was to investigate the influence of different aerobic intensities on
oxidative DNA damage and repair in middle aged men by means of the Comet assay. Five PA
males and five physically inactive males were assigned to an experimental and control group
respectively. The subjects did not differ significantly at baseline. The VO2-max of each subject
was determined at baseline. Subjects were then randomly assigned to 60, 70, 80 and 90% of
individual baseline VO2-max intensities for an acute exercise intervention of 30 minutes on a
bicycle ergometer. Blood sampling was done at baseline, post-exercise and 24 hours post-exercise
for oxygen radical absorbance capacity (ORAC) and hydroperoxide analysis (dROM).
Peripheral blood was obtained for DNA damage testing by means of Comet analysis at baseline,
post-exercise, 5, 15, 30 minutes, and also 6, 12, 24, 48 and 72 hours after exercise. The results
obtained indicated that subjects who regularly participate in PA had an increased baseline
reading of ORAC and dROM values. ORAC levels after each acute exercise session increased,
with the highest increase in the control group, with a decrease in the direction of baseline
readings 24 hours post exercise. A biphasic damage-repair cycle over the 72 hour period was
observed with the Comet analysis. The most damaged cells occur directly after acute exercise.
The highest incidence of DNA damage over a 72 hour period was observed at 70% VO2-max,
with the least amount of damage after 90% VO2-max.
In conclusion the study indicates stress proteins or other kinds of physiological reaction to
minimize the damaging effect of oxidative stress, is in place to restore the cell's homeostasis.
Thus PA results in the development of oxidative DNA damage. To minimize DNA damage the
optimal intensity for acute physical exercise is between 70-80% VO2-max. At higher intensities
the release of stress proteins are initiated to buffer the damaging effect of oxidative stress and to
restore homeostasis. / Thesis (M.Sc. (Human Movement Science))--North-West University, Potchefstroom Campus, 2007.
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Poruchy buněčného metabolismu jako společný patofyziologický mechanismus onemocnění CNS / Impairment of cellular metabolism as common pathophzsiological mechanism of CNS diseasesHasala, Ondřej January 2012 (has links)
Name of thesis: Impairment of cellular metabolism as common pathophysiological mechanism of CNS diseases Problem definition: Every human cell needs energy for living. If the prodcution of ATP (as an universal energy carrier) is broken, cell restricts its activity first and during longterm depletion of ATP, dies. It was found, that cellular metabolism is broken in most pathologies in CNS. Disorder of respiratory chain by free radicals is the best known at Parkinson's disease, epilepsy, brain ischemia etc. Mitochondria, where respiratory chain is situated, is not only the aim of free radicals, but it is their major producer. The activity of respiratory chain decreases during the life and this phenomenan is called aging. Aim of thesis: To determine whether there is increased production of free radicals in mitochondria of rat (LE Wistar) hippocampus during the epileptic seizure. Method: Thesis involves experiment which was done with acute rat hippocampal slices. To induce epileptic seizure it was used 4-aminopyridine model. It was used fluorescence imaging as imaging method. Changes of superoxide production was detected with MitoSOX. Electrophysiological record was taken by programme Spike 2 with stimulation and recording electrode inside the slice. Results: There was no significant difference between...
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Efeito do tratamento com antioxidantes e ácidos graxos poli-insaturados em amostras espermáticas epididimárias de touros / Effect of antioxidant and poli-unsaturated fatty acids on epididymal sperm in bullsNichi, Marcilio 27 November 2009 (has links)
Amostras espermáticas provenientes do epidídimo podem ser utilizadas com diversas finalidades tais como: modelo experimental para pesquisa com sêmen, aproveitamento do sêmen de animais de alto valor genético que vierem a óbito e possibilidade da coleta e aproveitamento do sêmen de animais em perigo de extinção. No entanto, para a utilização desta técnica é necessário o estudo de diversos fatores que poderiam influenciar sua eficiência, como por exemplo, as formas de armazenamento dos testículos, efeitos da criopreservação, diluidores utilizados, entre outros. O presente estudo teve como objetivos: 1- determinar a temperatura mais adequada para o armazenamento do testículo após o abate do animal (4 ou 34ºC) levando-se em consideração testes funcionais e fecundação in vitro; 2- avaliar o efeito desta temperatura de armazenamento no sêmen epididimário fresco e criopreservado e; 3- verificar a eficiência do tratamento com ácido decosaexanóico (DHA) e antioxidantes adicionados ao diluidor. Para isso, amostras espermáticas foram coletadas da cauda do epidídimo de touros provenientes de abatedouros. Para testar o efeito da temperatura de acondicionamento dos testículos, os mesmos foram armazenados entre 2 e 4 horas após o abate, à temperatura de 4 ou 34º C. O sêmen foi então coletado da cauda do epidídimo, submetido ou não à criopreservação e avaliado quanto a análise computadorizada da motilidade espermática (CASA), integridade de membrana e potencial mitocondrial (iodeto de propídeo, SYBR e JC1), fertilização in vitro e susceptibilidade ao estresse oxidativo (TBARS). Visto que os resultados deste experimento indicaram que a temperatura de 4ºC era a mais indicada, a mesma foi utilizada para a avaliação do efeito da suplementação com DHA e antioxidantes adicionados ao diluidor. Nesta fase, o sêmen foi avaliado quanto à integridade de membrana e acrossomo (eosina/nigrosina e fast green/rosa bengala, respectivamente), atividade mitocondrial (diaminobenzidina), integridade do DNA (ensaio da estrutura da cromatina espermática SCSA) e susceptibilidade ao estresse oxidativo (TBARS). Os resultados do presente estudo indicam que o tratamento com o DHA tornou os espermatozóides mais susceptíveis aos danos causados pelo estresse oxidativo. Por outro lado, resultados diversos foram encontrados com a associação entre DHA e antioxidantes. A associação entre DHA e superóxido dismutase (SOD) e DHA e glutationa reduzida (GSH) apresentaram os melhores resultados em relação à motilidade espermática e à integridade de membrana, respectivamente. No entanto, o DHA, quando associado à Vitamina E, apresentou resultados negativos para a atividade mitocondrial. Os resultados do presente estudo indicam que o tratamento com DHA e SOD ou DHA e GSH em amostras espermáticas coletadas de epidídimos armazenados a 4ºC por até 4 horas, pode melhorar a qualidade espermática pós criopreservação. / Sperm recovery from the cauda epididymis can be very advantageous, for example: in case of the unexpected death of a genetically highly valuable animal, as an experimental model for research on semen and for the use in endangered species. However, the efficiency of this technique demands the study of several issues such as the storage conditions of the testicles prior semen collection, the effects of cryopreservation and semen extenders, among others. The objective of the present study was: 1- to evaluate the ideal temperature for testicles storage after slaughter (4 or 34ºC) based on functional tests and on in vitro fertility; 2- to evaluate the effect of storage temperature on fresh and cryopreserved semen samples, and; 3- to test the addition of decosaexanoic acid (DHA) and antioxidants to the semen extender. Sperm samples were collected from the caudae epididymides of testicles collected from abattoirs. To test the effect of temperature of storage, testicles were kept under 4 or 34ºC, between two to four hours after slaughter. Semen was then collected from the caudae epididymides and cryopreserved or not. Samples were then evaluated for computer assisted sperm analysis (CASA), membrane integrity and mitochondrial potential (propidium iodide, SYBR and JC1), in vitro fertilization outcomes, and susceptibility to the oxidative stress (TBARS). Results of this study indicated that, with no doubt, storage of testicles under 4ºC is the most appropriate in order to improve post-thaw sperm quality and in vitro fertility. Therefore, this temperature was used in the rest of the study to test the effect of DHA and antioxidant treatments to the semen extender. In this part of the study, semen was evaluated for membrane and acrosome integrities (eosin/nigrosin and fast green/bengal rose stain, respectively), mitochondrial activity (diaminobenzidine stain), DNA integrity (sperm chromatin structure assay SCSA) and, sperm susceptibility to the oxidative stress (TBARS). Results of the present study indicate that due to the treatment with DHA, epididymal sperm became more susceptible to the oxidative stress. On the other hand, different results were found regarding the association between DHA and antioxidant. The association between DHA and superoxide dismutase (SOD) and between DHA and reduced glutathione (GSH) showed better results on sperm motility and membrane integrity, respectively. On the other hand, when associated to the Vitamin E, the DHA showed poor results on mitochondrial activity. Results of the present study indicate that the treatment with DHA and SOD or GSH to epididymal sperm samples collected from testicles stored at 4ºC for up to 4 hours, may improve post-thaw sperm quality.
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Efeito hipolipemiante e antioxidante de subprodutos da uva em hamsters / Hypolipidemic and antioxidant effects of grape processing byproducts in hamstersIshimoto, Emilia Yasuko 13 May 2008 (has links)
Introdução: Recentes pesquisas têm indicado o enorme potencial de certas substâncias alimentares, como polifenóis antioxidantes e fibras na redução de riscos de doenças crônicas. O bagaço de uva, subproduto do processamento de vinhos e sucos, representa uma ótima fonte de fibras e antioxidantes naturais de baixo custo. Objetivo: Avaliar o potencial hipolipemiante, antioxidante e sensorial de subprodutos do processamento do vinho e do suco. Métodos: Para avaliar a capacidade antioxidante in vitro, foi utilizado o método do DPPH. O potencial antioxidante e hipolipemiante in vivo foi avaliado mediante ensaio biológico, no qual sessenta hamsters foram divididos em seis grupos diferenciados pelas dietas: controle, hiperlipemiante, extrato de bagaço do vinho (BV), extrato de bagaço do suco (BS), suplementada com BV e suplementada com BS. Amostras de sangue e fígado foram coletadas após 4 semanas de experimento para avaliação do perfil lipídico, capacidade de inibição da oxidação de LDL-colesterol (LDL-c) e atividade das enzimas antioxidantes superóxido dismutase (SOD), catalase (CAT) e glutationa peroxidase (GPx). Para a avaliação sensorial, foram desenvolvidos sorbet e picolé de BV e BS, cujos atributos sensoriais foram avaliados por 43 pessoas aplicando-se o método afetivo de escala hedônica de 9 pontos. Resultados: Extratos de BV e BS apresentaram uma expressiva capacidade antioxidante in vitro. No modelo animal, os grupos tratados com BV e BS apresentaram uma melhora significativa do perfil lipídico e da atividade da enzima CAT, em relação aos grupos controle e hipercolesterolêmico (p<0,05). Com relação aos valores de SOD, GPx e inibição da oxidação de LDL-c, observou-se melhores resultados em relação ao grupo hipercolesterolêmico, embora não significativamente em todos os grupos tratados. Na análise sensorial, somente o picolé de BV não preencheu totalmente os requisitos de aceitação. Conclusão: Os subprodutos de ambas as espécies de uva apresentaram potencial biológico e sensorial para serem utilizados como ingredientes funcionais. / Introduction: Recent studies have shown the great potential of certain food components such as antioxidant polyphenols and fiber in reducing the risk of chronic diseases. Grape pomace, a wine and juice processing byproduct, is a low cost material and a very good source of fiber and natural antioxidants. Objectives: To evaluate the hypolipidemic, antioxidant and sensory potential of wine and grape byproducts. Methods: To evaluate the in vitro antioxidant capacity, the DPPH method was used. The in vivo antioxidant and hypolipidemic potential was evaluated through an animal model, in which sixty hamsters were divided into six groups according to their diets: control, hyperlipidemic, wine pomace (WP) extract, juice pomace (JP) extract, WP supplemented diet and JP supplemented diet. Samples of blood and liver were collected after a 4-week experimental period to evaluate the lipid profile, ability to inhibit the LDL-cholesterol (LDL-c) oxidation and antioxidant activity of superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx) enzymes. For the sensory evaluation, BV and BS sorbet and popsicle were developed, and the sensory attributes were evaluated by 43 tasters according to a 9- point affective hedonic scale. Results: WP and JP extracts showed a very good in vitro antioxidant capacity. In the animal model, both WP and JP treated groups presented a significant improvement in the lipid profile and CAT enzyme antioxidant activity in comparison to hypercholesterolemic and control groups (p <0.05). Regarding the values of SOD, GPx and inhibition of LDL-c oxidation, there values were better when compared to hypercholesterolemic group, even though they were not significant in all treated groups. In the sensory evaluation, only the BV popsicle was not fully accepted. Conclusion: Both grapes byproducts showed a biological and sensory potential to be used as functional ingredients.
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