Each year in the U.S., approximately 7-8 million patients with non-traumatic chest pain visit hospital emergency departments (ED) for medical evaluation. It is estimated that approximately 2-5% of these patients are experiencing acute cardiac ischemia, but due to the shortcomings of current test methods, they are incorrectly diagnosed and discharged without appropriate treatment provided, thus leading to poor patient outcome and potential medical malpractice litigation.The goals of this research were to evaluate plasma samples for potential biomarker(s) of acute cardiac ischemia prior to heart tissue necrosis, and to ultimately develop a rapid method for detection of the potential biomarker(s) in human plasma. Initial experiments were performed using the mouse model, with subsequent evaluations on human plasma samples using high performance liquid chromatographic ultraviolet detection (HPLC-UV). The final phase of this research involved the development of a rapid luminometer test method (An HPLC-UV detection method was developed and utilized for inosine, hypoxanthine and other adenosine triphosphate (ATP) catabolic by-products in Krebs-Henseleit (Krebs) buffer solution, with analysis on perfusate samples from isolated mouse hearts undergoing 20 min acute global ischemia. The HPLC-UV method was modified for subsequent use on human plasma samples, obtained from hospital emergency department (ED) patients presenting with non-traumatic chest pain (potential acute cardiac ischemia) and from healthy normal individuals. The HPLC-UV (component quantification) and HPLC-MS (component identification) test methods utilized C18 column technology, mobile phases consisting of aqueous trifluoroacetic acid (0.05% TFA in deionized water pH 2.2, v/v) and methanol gradient to achieve component separation, with both utilizing simple sample preparations (e.g. direct injection of Krebs perfusate samples and centrifugal membrane filtration on plasma samples).Results of the animal experiments using isolated mouse hearts undergoing 20 min acute global ischemia demonstrated significant levels of endogenous inosine effluxed from the heart tissue, indicating its use as a potential candidate biomarker of acute cardiac ischemia. The HPLC results from human plasma representing ED non-traumatic chest pain patients demonstrated elevated levels of inosine (hypoxanthine precursor) and significant levels of hypoxanthine, which provided additional support for the use of these candidate biomarker(s) as a potential diagnostic tool for the initial acute cardiac ischemic event, prior to heart tissue necrosis.The final phase of this research focused on the development of a rapid, simple and sensitive chemiluminescence test method. Using a microplate luminometer with direct injectors and continuous mixing, the measurement of inosine and hypoxanthine in human plasma was achieved for healthy normal individuals and on patients with confirmed acute MI, with an analysis time of less than 5 minutes. The utility of this rapid luminescence technique would be the potential use at point-of-care (POC) services (e.g. hospital clinical laboratory or emergency medical services) as part of the initial ED treatment protocol on patients presenting with non-traumatic chest pain and signs/symptoms of acute myocardial ischemia or acute MI.

As peçonhas de artrópodos são ricas fontes de neurotoxinas, verdadeiras ferramentas moleculares com ação seletiva e específica sobre o Sistema Nervoso Central (SNC) de mamíferos, e de grande relevância clínico-científica. Demonstramos recentemente que a peçonha de P. bistriata, quando injetada por via intracerebroventricular (i.c.v.), desencadeava crises convulsivas em ratos, um indício da existência de neurotoxinas pró-convulsivantes na peçonha dessa aranha. O grupo do Prof. Dr. Joaquim Coutinho-Netto isolou da peçonha dessa aranha várias neurotoxinas, dentre as quais uma denominada PbTx 2.2.1, que possui a capacidade de inibir a captação do neurotransmissor GABA em sinaptosomas corticais de ratos (in vitro), uma ação considerada como potencialmente anticonvulsivante. As frações PbTx 2.2.1 e 1.2.3 protegem retinas de ratos após isquêmia. Mas, não se testou o efeito anticonvulsivante dessa fração em experimentos in vivo. O presente trabalho teve dois objetivos: 1- Propor um método cromatográfico para isolar da peçonha de aranhas, neurotoxinas pró-convulsivantes não protéicas e de baixo peso molecular. Isolar e caracterizar parcialmente estas neurotoxinas da peçonha da aranha P.bistriata; 2- verificar se a fração PbTx 2.2.1 possui efeito anticonvulsivante in vivo. O isolamento da peçonha de P. bistriata, realizado com filtração em gel (Sephadex G-50 e G-25), cromatografia líquida de alta eficiência (CLAE) (colunas de fase reversa e troca catiônica), e CLAE-acoplado a espectrometria de massa (CLAE-MS) produziu uma fração (fração 7) e um subcomponente (fração 7.1) com atividade pró-convulsivante, após injeção i.c.v. Tal fração apresenta características típicas de ácidos nucléicos. Confirmou-se, através de ressonância magnética nuclear (RMN) que o constituinte majoritário desta fração é o nucleosídeo inosina. O método cromatográfico mostrou-se muito lento. Uma outra fração (fração 6) da mesma peçonha inibiu as crises causadas por bicuculina i.c.v., ao passo que a fração 1 apresentou atividade de fosfatase ácida e alcalina. A injeção i.c.v. da fração PbTx 2.2.1, 20 min antes do convulsivante bicuculina também i.c.v., bloqueou as crises convulsivas em 71,4% dos animais, o que caracteriza um efeito anticonvulsivante in vivo desta fração. Conclui-se que: 1- A peçonha de P. bistriata possui, dentre muitas, uma fração (fração 7) com efeito pró-convulsivante quando injetada i.c.v. em ratos. Nesta fração, aparentemente o composto majoritário é o nucleosídeo inosina. A peçonha da mesma aranha possui também uma fração com atividade anticonvulsivante (fração 6) e outra com atividade de fosfatase ácida e alcalina (fração 1). 2- o método cromatográfico proposto pode ser otimizado talvez pelo uso de ultrafiltração; 3- a fração PbTx 2.2.1 apresenta efeito anticonvulsivante in vivo no modelo de indução de crises por injeção i.c.v. de bicuculina. / Arthropod venoms are rich sources of neurotoxins, molecular tools with selective and specific actions over the mamalian central nervous system with great clinical and scientific importance. Previous work of our laboratory showed that the spider venom of Parawixia bistriata, when injected by intracerebroventricular (i.c.v.) route, induced convulsive seizures in rats, a sign of convulsant neurotoxins. The group of Professor Joaquim Coutinho-Netto isolated from this spider venom a neurotoxin called PbTx 2.2.1 which is a GABA transporter inhibitor in the rat cortical synaptosomal preparation (in vitro), a potencially anticonvulsant property. The fractions PbTx 2.2.1 and 1.2.3 protected retinal cells against isquemy. But, it has not been tested if the PbTx 2.2.1 fraction also has an in vivo anticonvulsant action. Present work has two objectives: 1- to propose a chromatographic methodology to isolate non-proteic low molecular weigh convulsant neurotoxins from spider venoms. Isolate and partially characterize these neurotoxins from P. bistriata venom; 2- test if PbTx 2.2.1 has in vivo anticonvulsant effect. Biochemical venom isolation by gel filtration (Sephadex G-50 and G-25), reverse phase and cationic exchange in high pressure liquid cromatography (HPLC) and also HPLC coupled to mass spectrometry (HPLC-MS), has pointed that the P. bistriata spider venom has a fraction (fraction 7) and a subfraction (7.1) with convulsant activity when injected i.c.v. in rats. Fraction 7 has nucleosidic characteristics. Nuclear magnetic ressonance (NMR) has showed that the principal component of this fraction is the nucleoside iosine. An other fraction (fraction 6) isolated from the same venom, inhibited seizures induced by i.c.v. bicuculine and the fraction 1 showed acid and basic phosphatase activity PbTx 2.2.1, when injected i.c.v. 20 min prior to the convulsant bicuculline (i.c.v.), has blocked seizures in 71.4 % of the animals, what was considered an anticonvulsant effect. The conclusions are: 1- the spider venom of P. bistriata has a fraction (fraction 7) with convulsant action when injected i.c.v. in rats. The major component of this fraction is the nucleoside iosine. This spider venom also has another fraction (fraction 6) with anticonvulsant activity and one with acid and alcaline phosphatase (fraction 1); 2- the chomatographic methodology can be improved, perhaps by ultrafiltration methods; 3- the PbTx 2.2.1 fraction has anticonvulsant effect in vivo.

As peçonhas de artrópodos são ricas fontes de neurotoxinas, verdadeiras ferramentas moleculares com ação seletiva e específica sobre o Sistema Nervoso Central (SNC) de mamíferos, e de grande relevância clínico-científica. Demonstramos recentemente que a peçonha de P. bistriata, quando injetada por via intracerebroventricular (i.c.v.), desencadeava crises convulsivas em ratos, um indício da existência de neurotoxinas pró-convulsivantes na peçonha dessa aranha. O grupo do Prof. Dr. Joaquim Coutinho-Netto isolou da peçonha dessa aranha várias neurotoxinas, dentre as quais uma denominada PbTx 2.2.1, que possui a capacidade de inibir a captação do neurotransmissor GABA em sinaptosomas corticais de ratos (in vitro), uma ação considerada como potencialmente anticonvulsivante. As frações PbTx 2.2.1 e 1.2.3 protegem retinas de ratos após isquêmia. Mas, não se testou o efeito anticonvulsivante dessa fração em experimentos in vivo. O presente trabalho teve dois objetivos: 1- Propor um método cromatográfico para isolar da peçonha de aranhas, neurotoxinas pró-convulsivantes não protéicas e de baixo peso molecular. Isolar e caracterizar parcialmente estas neurotoxinas da peçonha da aranha P.bistriata; 2- verificar se a fração PbTx 2.2.1 possui efeito anticonvulsivante in vivo. O isolamento da peçonha de P. bistriata, realizado com filtração em gel (Sephadex G-50 e G-25), cromatografia líquida de alta eficiência (CLAE) (colunas de fase reversa e troca catiônica), e CLAE-acoplado a espectrometria de massa (CLAE-MS) produziu uma fração (fração 7) e um subcomponente (fração 7.1) com atividade pró-convulsivante, após injeção i.c.v. Tal fração apresenta características típicas de ácidos nucléicos. Confirmou-se, através de ressonância magnética nuclear (RMN) que o constituinte majoritário desta fração é o nucleosídeo inosina. O método cromatográfico mostrou-se muito lento. Uma outra fração (fração 6) da mesma peçonha inibiu as crises causadas por bicuculina i.c.v., ao passo que a fração 1 apresentou atividade de fosfatase ácida e alcalina. A injeção i.c.v. da fração PbTx 2.2.1, 20 min antes do convulsivante bicuculina também i.c.v., bloqueou as crises convulsivas em 71,4% dos animais, o que caracteriza um efeito anticonvulsivante in vivo desta fração. Conclui-se que: 1- A peçonha de P. bistriata possui, dentre muitas, uma fração (fração 7) com efeito pró-convulsivante quando injetada i.c.v. em ratos. Nesta fração, aparentemente o composto majoritário é o nucleosídeo inosina. A peçonha da mesma aranha possui também uma fração com atividade anticonvulsivante (fração 6) e outra com atividade de fosfatase ácida e alcalina (fração 1). 2- o método cromatográfico proposto pode ser otimizado talvez pelo uso de ultrafiltração; 3- a fração PbTx 2.2.1 apresenta efeito anticonvulsivante in vivo no modelo de indução de crises por injeção i.c.v. de bicuculina. / Arthropod venoms are rich sources of neurotoxins, molecular tools with selective and specific actions over the mamalian central nervous system with great clinical and scientific importance. Previous work of our laboratory showed that the spider venom of Parawixia bistriata, when injected by intracerebroventricular (i.c.v.) route, induced convulsive seizures in rats, a sign of convulsant neurotoxins. The group of Professor Joaquim Coutinho-Netto isolated from this spider venom a neurotoxin called PbTx 2.2.1 which is a GABA transporter inhibitor in the rat cortical synaptosomal preparation (in vitro), a potencially anticonvulsant property. The fractions PbTx 2.2.1 and 1.2.3 protected retinal cells against isquemy. But, it has not been tested if the PbTx 2.2.1 fraction also has an in vivo anticonvulsant action. Present work has two objectives: 1- to propose a chromatographic methodology to isolate non-proteic low molecular weigh convulsant neurotoxins from spider venoms. Isolate and partially characterize these neurotoxins from P. bistriata venom; 2- test if PbTx 2.2.1 has in vivo anticonvulsant effect. Biochemical venom isolation by gel filtration (Sephadex G-50 and G-25), reverse phase and cationic exchange in high pressure liquid cromatography (HPLC) and also HPLC coupled to mass spectrometry (HPLC-MS), has pointed that the P. bistriata spider venom has a fraction (fraction 7) and a subfraction (7.1) with convulsant activity when injected i.c.v. in rats. Fraction 7 has nucleosidic characteristics. Nuclear magnetic ressonance (NMR) has showed that the principal component of this fraction is the nucleoside iosine. An other fraction (fraction 6) isolated from the same venom, inhibited seizures induced by i.c.v. bicuculine and the fraction 1 showed acid and basic phosphatase activity PbTx 2.2.1, when injected i.c.v. 20 min prior to the convulsant bicuculline (i.c.v.), has blocked seizures in 71.4 % of the animals, what was considered an anticonvulsant effect. The conclusions are: 1- the spider venom of P. bistriata has a fraction (fraction 7) with convulsant action when injected i.c.v. in rats. The major component of this fraction is the nucleoside iosine. This spider venom also has another fraction (fraction 6) with anticonvulsant activity and one with acid and alcaline phosphatase (fraction 1); 2- the chomatographic methodology can be improved, perhaps by ultrafiltration methods; 3- the PbTx 2.2.1 fraction has anticonvulsant effect in vivo.

No description available.

In clinical diagnostics and research, blood samples are one of the most frequently used materials. Nevertheless, exploring the chemical composition of human plasma and serum is challenging due to the highly dynamic influence of pre-analytical variation. A prominent example is the variability in pre-centrifugation delay (time-to-centrifugation; TTC). Quality indicators (QI) reflecting sample TTC are of utmost importance in assessing sample history and resulting sample quality, which is essential for accurate diagnostics and conclusive, reproducible research. In the present study, we subjected human blood to varying TTCs at room temperature prior to processing for plasma or serum preparation. Potential sample QIs were identified by Ultra high pressure liquid chromatography tandem mass spectrometry (UHPLC-MS/MS) based metabolite profiling in samples from healthy volunteers (n = 10). Selected QIs were validated by a targeted MS/MS approach in two independent sets of samples from patients (n = 40 and n = 70). In serum, the hypoxanthine/guanosine (HG) and hypoxanthine/inosine (HI) ratios demonstrated high diagnostic performance (Sensitivity/Specificity > 80%) for the discrimination of samples with a TTC > 1 h. We identified several eicosanoids, such as 12-HETE, 15-(S)-HETE, 8-(S)-HETE, 12-oxo-HETE, (±)13-HODE and 12-(S)-HEPE as QIs for a pre-centrifugation delay > 2 h. 12-HETE, 12-oxo-HETE, 8-(S)-HETE, and 12-(S)-HEPE, and the HI- and HG-ratios could be validated in patient samples.

The importance of nucleic acids in plant and animal cells as carriers of genetic information and as protein biosynthesis agents is well recognized. It is also known that nucleic acid is a component of all viruses. Takahashi (45) and Fraenkel-Conrat (16) demonstrated that the protein component of tobacco mosaic virus is non-infectious to the host plant, although it is identical to the original virus morphologically. The virus ribonucleic acid (RNA) alone was infectious, however. Deoxyribonucleic acid (DNA), which is present in chromosomes, displays a very specific function. The chromosome long has been accepted as the carrier of the hereditary unit, the gene, whose main component is DNA, which controls the formation of enzymes and of many proteins. Agents that bring about a mutational effect, affect DNA. Some of these agents are ultraviolet light, X-ray radiation and nitrous acid.

Les éléments Alu sont les retrotransposons les plus prolifiques chez l'humain avec plus d'1 million de copies occupant plus de 10% du génome. Afin de contrecarrer l'expansion des rétro-éléments, les organismes ont développés différents mécanismes pour préserver l'intégrité de leurs génomes. Le plus proéminent, également utilisé pour lutter contre la réinsertion d'ADN viral dans le génome hôte, est l'édition de l'ARN. Chez les mammifères, la plus courante est la déamination de l'adénine en inosine catalysée par la famille de protéine ADAR dont Les principales cibles sont les éléments Alu chez l'humain. L'édition des éléments Alu conduit à leur séquestration dans le noyau des cellules, mute leurs promoteurs internes, cible de l'ARN polymérase III (POLIII), et leurs queues poly-A, prévenant ainsi leur future rétrotransposition. Dans la première partie de cette étude, l'analyse de données de séquençage haut-débit révèle que ~40% des éléments Alu sont reconnus par POLIII, qu'ils sont présents en tant que petits ARN dans le cytoplasme et le noyau des cellules, que certain d'entre eux sont associés à la chromatine, et que la transcription des éléments Alu est un phénomène courant dans les tissus somatiques qui concorde avec l'expression d'éléments LINE1 fonctionnels. Ceci suggère que la rétrotransposition peut être un mécanisme normal dans la plupart des tissus humains. Enfin, l'analyse de l'expression des éléments Alu et LINE1 chez la souris montre que la transcription de rétrotransposons n'est pas spécifique de l'humain. Dans la seconde partie de cette étude, une nouvelle méthode a été développée pour explorer l'impact de l'édition de l'ARN sur le transcriptome en identifiant les ARN édités par séquençage haut-débit. Dans un premier temps, un anticorps ciblant ADAR a été utilisé pour extraire les ARN associés aux protéines de l'édition. Cette méthode n'étant pas suffisamment efficace, une autre stratégie, qui extrait directement les ARN contenant de l'inosine, a été développée : dans un premier temps, l'ARN est fixé à des billes magnétiques par leurs extrémités 3', ensuite, les billes sont traitées au glyoxal/acide borique et à la RNAse T1 pour libérer la région 5' des ARN contenant une ou plusieurs inosines, et enfin, les ARN libérés sont séquencés par séquençage haut débit. En utilisant cette méthode, 1822 sites d'éditions ont été identifiés dans l'ARN de cerveau de souris, incluant 28 nouveaux sites présents dans des séquences codantes qui conduisent à des mutations non-synonymes des futures protéines. Des sites d'éditions ont aussi été observés pour la première fois dans les ARN ribosomaux, les snoRNA et les snRNA.

The umami sensation contributes to beef flavor and acceptability. Inosine 5’- monophosphate (IMP) was the most abundant nucleotide in meat known to impart umami taste which thus far had been overlooked in meat flavor studies. The objectives of this study were to determine the umami taste threshold of inosine 5'-monophosphate (IMP), the effects of spiking IMP on the sensory descriptive attributes of various USDA graded beef strip steaks, and to differentiate beef by IMP content using electrochemistry. USDA Prime, Choice, and Select steaks were spiked with 0.3 and 0.6 mM IMP and analyzed chemically and organoleptically. Liquid chromatography-mass spectrometry and descriptive sensory analysis showed no changes in IMP content and the perceived sensory attributes of steaks. The electrochemical approach successfully differentiated IMP concentrations in aqueous solutions when present at 0.5 mM or above and was able to recognize the presence of nucleotides in the meat extract.

No description available.

Pavel Jůda - Abstract The cell nucleus is a complex cellular organelle. The nucleus and nuclear processes are organized into functionally and morphologically separated nuclear subcompartments. This thesis is particularly concerned with the three following nuclear subcompartments: sites of DNA replication, Polycomb bodies and nuclear inclusions constituted of inosine monophosphate dehydrogenase 2 (IMPDH2). First, we examined the relationship between MCM proteins and DNA replication. Using immunofluorescent labeling of cells extracted prior fixation and applying cross-correlation function analysis, we showed that MCM proteins are present at the sites of active DNA synthesis. Our results contributed to the solving of the first part of so-called MCM paradox. Second, we studied the structural basis of the Polycomb bodies. Based on fluorescence microscopy studies, Polycomb bodies have been considered to be the nuclear subcompartments formed by the accumulation of Polycomb proteins in the interchromatin compartment. In our work, using correlative light electron microscopy and experimental changes in macromolecular crowding, we clearly showed that a Polycomb body is a chromosomal domain formed by an accumulation of heterochromatin structures, rather than a typical nucleoplasmic body. Third, we were interested in...