• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 51
  • 11
  • 5
  • 2
  • 1
  • 1
  • 1
  • Tagged with
  • 79
  • 79
  • 45
  • 44
  • 24
  • 16
  • 11
  • 11
  • 10
  • 10
  • 9
  • 8
  • 8
  • 8
  • 7
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
61

Bacterial toxins for cancer treatment

Johansson, David January 2008 (has links)
Even though anti‐cancer chemotherapy has been continuously improved during the last decades. problems with adverse effects and drug resistance still constitutes a considerable obstacle and sets a demand for new effective treatment options. Tissue homeostasis in multi‐cellular organisms is maintained through intrinsic cell death, apoptosis, which removes unwanted or damaged cells. Disrupted apoptosis is an important factor in tumorgenesis and drug resistance, therefore induction or restoration of apoptotic pathways is also important for the treatment of cancer. Several naturally occurring bacterial toxins have the ability to induce apoptosis and could thus be candidates to complement or improve the therapeutic effect of other anticancer drugs. The bacterial toxins, adenylate cyclase (AC) toxin from Bordetella pertussis, α‐toxin from Staphylococcus aureus and verotoxin‐1 (VT‐1) from Escherichia coli were investigated for their ability to induce apoptosis in different tumor cell lines. Toxin induction of cell death was investigated by cell viability assays, end‐stage apoptosis induction by DNA‐fregmentation (TUNEL) assay. Toxin receptor expression and signal transduction pathways to apoptosis were investigated by flow cytometry, caspase enzyme activity assays and western blot. Immunohistochemistry was used for identification of toxin receptor expression in tumor tissue samples. AC‐toxin was cytotoxic and induced apoptosis in cultured malignant plural mesothelioma (MPM) and small‐cell lung cancer (SCLC) cells. Low‐toxic concentrations of AC‐toxin enhanced cisplatin cytotoxicity and apoptosis in both cell lines. MPM‐cells with acquired cisplatin resistance were more sensitive to α‐toxin than the less resistant parental MPM cell line. A low‐toxic concentration of α‐toxin re‐sensitized resistant MPM cells to cisplatin cytotoxicity by apoptosis induced through the mitochondrial pathway without detectable activation of common up‐stream apoptosis signalling proteins. VT‐1 was highly cytotoxic and induced apoptosis in globotriosylceramide (Gb3) ‐expressing glioma, breast cancer and non‐small‐cell lung cancer (NSCLC) cells but was not cytotoxic to non‐Gb3‐expressing cells. PPMP, an inhibitor of glucosylceramide synthesis which makes exposed cells unable to synthesize Gb3 rendered Gb3‐expressing cells resistant to VT‐1. MPM cells with acquired‐cisplatin resistance expressed Gb3 in contrast to the absent of expression in the less resistant parental cell line. Gb3, could however be up‐regulated by cisplatin in Gb3‐negative MPM‐cells. Presence of a low‐toxic concentration of VT‐1 potentiated cisplatin‐induced cytotoxicity and apoptosis in the cisplatin‐resistance MPM cell line. VT‐1 was a potent inducer of apoptosis, probably via stress‐induced Mitogen‐activated protein kinase (MAPK)‐signaling involving c‐Jun N‐terminal kinase (JNK) and p38, leading to disruption of the mitochondrial membrane integrety, activation of caspase‐9 and ‐3, and ultimately DNA fragmentation and cell death. Gb3 expression was demonstrated in clinical specimens of glioblastoma and breast cancer making these tumor types interesting for further VT‐1 studies. We conclude that bacterial toxins may be used to induce apoptosis in several types of cancer cells. Low concentrations of verotoxin‐1 and α‐toxin may potentially be used to overcome acquired cisplatin‐resistance in cancer patients.
62

Bestämning av syntetiska cannabinoider med gaskromatografi-masspektrometri / Determination of synthetic cannabinoids by gas chromatography-mass spectrometry

Pettersson, Sandra January 2011 (has links)
This thesis has been performed at Clinical Chemistry at Sahlgrenska University Hospital in Gothenburg. The purpose of the project was to investigate new and alternative ways to determinate synthetic cannabinoids by gas chromatography-mass spectrometry. Currently, the possibilities to quantify synthetic cannabinoids are very limited. This can lead to an increased use of synthetic cannabinoids as the risk of detection is low, which may be known by drug users. The synthetic cannabinoids are sold mixed with different herbs and have varying names like Spice Gold, Spice Silver, K2, Smoke and Pot-pourri. The synthetic cannabinoids analyzed were JWH-018 and JWH-073, which are commonly found in seized Spice material. At intake of these drugs, usually through smoking, cannabis-like effects arise. This is because they bind to cannabinoid receptors in a similar way as THC does, which is the primary active cannabinoid of cannabis. For urine samples an analytical method would probably be the most sensitive if the major metabolite could be analyzed, as it is expected to be present in high concentrations in this sample type. Since information regarding the metabolism of synthetic cannabinoids is very limited there may be reasons to analyze the mother substance in urine. Further, in plasma and serum samples the mother substance is expected in high concentrations. Thus different ways to detect JWH-018 and JWH-073 directly were investigated in this project. Derivatization of JWH-018 and JWH-073 was the first step to get more selective and sensitive GC-MS analysis. Different derivatization-reagents were investigated, for example BSTFA and TFAA. The results show that the derivatization of JWH-018 with BSTFA after reduction and extraction was successful. To achieve this, samples had to be heated at 115°C for 1-3 hours, but still the samples were not completely derivatized. The results indicate that JWH-substances are difficult to derivatized, but they are possible to derivatize with BSTFA. This could mean that a GC-MS-method maybe could be established for these substances, preferably trough TFAA-derivatization.
63

A Comparison of Two Immunoturbidimetric Assay Methods for Serum Amyloid A in Cats.

Edblom, Sara January 2011 (has links)
The analysis of acute phase protein serum amyloid A (SAA) has recently been brought into clinical use in veterinary medicine. Some of the difficulties with incorporating the SAA method in clinical practice have been the expensive and rather large equipment required for the method. Due to these difficulties only larger clinics can afford to use the SAA analysis. The company Equinostic has recently developed a smaller instrument that costs one-tenth of a larger instrument. The instrument is named EVA1 and has so far only been used to analyze SAA in horses. The aim of this study was to investigate if the EVA1 instrument could be used to analyze SAA in cats. This study included 24 serum samples from cat, which were first analyzed twice on the EVA1 instrument and then sent to the Strömsholm Referral Animal Hospital in Sweden where they reanalyzed the samples using a validated reference method. Both instruments are based on an immunoturbidimetric assay. The correlation between the two instruments was good (r=0.97) but the EVA1 instrument showed constantly lower results than the reference method. The difference between the duplicates when analyzed on the EVA1 instrument was larger than expected. The conclusion is that EVA1 could be used to analyze SAA in cats. However, before it could be used clinically in veterinary practice an extended study is recommended.
64

Tipagem E Teste De Compatibilidade Sanguínea, Caracterização Hematológica E Bioquímica Em Felinos Selvagens E Domésticos / Blood typing and crossmatching, haematological and biochemical characterization in wild and domestic cats

SILVA, Talita Dayane Pereira e 31 May 2011 (has links)
Made available in DSpace on 2014-07-29T15:07:33Z (GMT). No. of bitstreams: 1 Dissertacao Talita Dayane Pereira e Silva.pdf: 3126915 bytes, checksum: 570135c97ada384da1836d9ed08ac153 (MD5) Previous issue date: 2011-05-31 / The neotropical felids are represented by ten species, having been Brazil eight host of these. These animals are constant victims of running over in highways and still they suffer with intense infestation for parasites, what it can result in intense anemia, being necessary the accomplishment of blood transfusion. In the present study blood samples were used of eight jaguarundies (Puma yagouaroundi), eight ocelots (Leopardus pardalis), seven pampas cats (Leopardus colocolo), seven domestic cats (Felis catus) of the Persian race and eight domestic cats (Felis catus) without definite race (SRD), whose aim was: a) to carry through blood typing and tests of compatibility between corresponding blood types in the different species; b) to carry through count blood cells (CBC), comparing the technique automatized by means of device BC - 2800 vet (software for domestic cats), with the manual technique for the wild species; and c) to carry through the profile biochemist and electrophoretic of serum proteins. In the typing, the occurrence of the blood type A was of 100% between ocelots, pampas cats and domestic cats Persian and of 85,72% between domestic cats SRD. 100% of the jaguarundies were type B and 14,28% of domestic cats SRD. To the tests of blood compatibility, 87,5% (n=4) of the ocelots were incompatible with domestic cats and 12,5% (n=1) were compatible; 100% (n= 6) of the pampas cats were compatible with domestic cats and 100% (n= 4) of the jaguarundies were incompatible with domestic cat of type B. It is concluded that in accordance with tests of blood compatibility the transfusion between domestic and pampas cats is possible, it is impossible the transfusion between domestic and jaguarundies and that more studies must be carried through for ocelots. In the comparison enters the techniques for the accomplishment of the CBC the automatized technique demonstrated statistical results equal for the majority of the parameters, also inside of the values of reference for the species, except in the counting of leukocytes of jaguarundies, whose resulted gotten for automation were bigger. It had good correlation between the techniques, mainly in the ocelot species. Concludes that device BC 2800 vet with the configuration for domestic cats is a technique fast and trustworthy in the accomplishment of blood cells count for species pampas cat and ocelot. The manual counting of leukocytes must be preferred for jaguarundies. The results gotten for many of the evaluated parameters biochemistries were similar to the described as values of reference for the studied species. However, the values found for ALT and AST were above of the values of reference for jaguarundies and ocelots. The value of glucose was above for the species pampas cat. The urea was above of the values of reference for the three species. The electrophoretic race for the analyzed species was similar to the described one for domestic cats contends albumen, alpha globulins (alpha 1 and 2), beta globulins (beta 1 and 2) and gamma globulins, however, in all the species had individuals that they had not presented beta globulin of the type beta 2. The gotten results can be used as normality parameters for the species pampas cat, ocelots and jaguarundies from Cerrado biome. / Os felídeos neotropicais são representados por dez espécies, sendo o Brasil hospedeiro de oito destas. Estes animais são constantes vítimas de atropelamentos em rodovias e sofrem com infestação intensa por parasitas, o que pode resultar em quadros de anemia intensa, necessitando transfusão sanguínea. No presente estudo foram utilizadas amostras sanguíneas de oito gatos mouriscos (Puma yagouaroundi), oito jaguatiricas (Leopardus pardalis), sete gatos palheiros (Leopardus colocolo), sete gatos domésticos (Felis catus) da raça Persa e de oito gatos domésticos (Felis catus) sem raça definida (SRD), cujo objetivo foi: a) realizar tipagens sanguíneas e testes de compatibilidade entre tipos sanguíneos correspondentes nas diferentes espécies; b) realizar hemogramas, comparando a técnica automatizada por meio do contador automático BC 2800 vet, com software para gatos domésticos, com a técnica manual para as espécies selvagens; e c) realizar o perfil bioquímico e eletroforético de proteínas séricas. Nas tipagens, a ocorrência do tipo sanguíneo tipo A foi de 100% entre as jaguatiricas, gatos palheiro e gatos domésticos Persa e de 85,72% entre os gatos domésticos SRD. 100% dos gatos mouriscos foi tipo B e 14,28% dos gatos domésticos SRD. Aos testes de compatibilidade sanguínea, 87,5% (n=4) das jaguatiricas foram incompatíveis com gatos domésticos e 12,5% (n=1) foram compatíveis; 100% (n= 6) dos gatos palheiros foi compatível com gatos domésticos e 100% (n= 4) dos gatos mouriscos foi incompatível com gato doméstico do tipo B. Conclui-se que, de acordo com testes de compatibilidade sanguínea, é possível não reação transfusional aguda entre gatos domésticos e palheiros, é impossível a transfusão entre gatos domésticos e mouriscos e que mais estudos devem ser realizados para jaguatiricas. Na comparação entre as técnicas para a realização do hemograma a técnica automatizada demonstrou resultados estatisticamente iguais para a maioria dos parâmetros, inclusive dentro dos valores de referência para as espécies, exceto na contagem de leucócitos de gatos mouriscos, cujos resultados obtidos por automação foram maiores. Houve boa correlação entre as técnicas, principalmente na espécie jaguatirica. Conclui-se que o aparelho BC 2800 vet com a configuração para gatos domésticos é uma maneira rápida e confiável na realização de hemogramas para as espécies gato palheiro e jaguatirica e que a contagem manual de leucócitos deve ser preferida para gatos mouriscos. Os resultados obtidos para muitos dos parâmetros bioquímicos avaliados foram semelhantes aos descritos como valores de referência para as espécies estudadas. No entanto, os valores encontrados para ALT e AST estavam acima dos valores de referência para gatos mouriscos e jaguatiricas e o valor de glicose estava acima para a espécie gato palheiro. A uréia estava acima dos valores de referência para as três espécies. A corrida eletroforética para as espécies analisadas foi semelhante à descrita para gatos domésticos contendo albumina, alfaglobulinas alfa 1 e alfa 2, betaglobulinas beta 1 e beta 2 e gamaglobulina, no entanto, em todas as espécies houveram indivíduos que não apresentaram betaglobulina do tipo beta 2. Os resultados obtidos podem ser utilizados como parâmetros de normalidade para as espécies gato palheiro, gato mourisco e jaguatirica do bioma Cerrado.
65

Jämförelse av kemiinstrument och validering av referensintervall hos hund och katt / Comparison of chemical instruments and validation of reference intervals in dogs and cats

Borg, Johanna January 2021 (has links)
Klinisk kemiska analyser har hög klinisk relevans. I serum/plasma kan olika parametrar kvantifieras. Dessa parametrar kan vara proteiner, enzymer, joner, metaller, lipider och kolhydrater. Med hjälp av referensintervall kan veterinärer ställa diagnos, följa behandling och sjukdomsförlopp. Parametrar detekteras med olika analysprinciper/metoder; kolorimetri, immunturbidimetri, enzymatisk metod och potentiometri. Djursjukhuset, AniCura, i Hässleholm mottagas både hundar och katter. Cirka 120 kemianalyser analyseras varje dag. AniCura har köpt in ett nytt våtkemiiinstrument, Indiko Plus, som ska ersätta Cobas C111. Med Indiko Plus tillkommer fler provpositioner, 8 nya analyser, ökad kapaciteten och underlättad användning.  Syftet med denna studie var att jämföra instrumenten och ta fram eget referensintervall som jämfördes med referensintervall framtaget av Thermo Fisher. Verifiering av det nya instrumentet genomfördes med precisionsstudie och linjäritetsstudie. Provtagning på hundar och katter utfördes av personal på AniCura. Jämförelsen gjordes med patientprover och referensintervall togs fram med hjälp av prover från friska hundar och katter. Jämförelsen visade att 9 av 13 analyser hade statistisk signifikant skillnad. Orsaken till det beror troligen på skillnaden av reagens, instrumentens ålder och tid mellan mätningar. Ett nytt referensintervall utarbetades och skiljde sig inte mycket från Thermo Fishers intervall. Vidare validering på grund av liten population rekommenderades. Precisionen för Indiko Plus blev godkänd. Linjäriteten blev icke linjär och berodde troligen på en dålig pipett och bör göras om. / Clinical chemical analyzes has high clinical relevance. In serum/plasma, different parameters can be quantified. Parameters can be proteins, enzymes, ions, metals, lipids, and carbohydrates. With reference intervals, veterinarians can set diagnosis, follow treatment and development of the disease. Parameters are detected with different analysis principles/methods; colorimetry, immunoturbidimetry, enzymatic method and potentiometry. The animal hospital, AniCura, in Hässleholm accept dogs and cats. About 120 chemical analyzes are analyzed every day. AniCura purchased a new instrument, Indiko Plus, which will replace Cobas C111. Indiko Plus provide, more sample positions, 8 new analyzes, increased capacity, and facilitated use. The purpose of this study was to compare the instruments and produce a new reference interval which was compared to the reference interval provided by Thermo Fisher. To verify Indiko Plus, a precision and linearity study were conducted. Blood sampling of dogs and cats was performed by staff at AniCura. The comparison was made with patient samples and the reference intervals were obtained using samples from healthy animals. The comparison showed 9 of 13 analyzes had a statistically significant difference. The reason for this is probably due to the difference in reagents, the age of the instruments and the time between measurements. A new reference interval was developed and did not differ much from the Thermo Fisher interval. Further validation due to low population was recommended. The precision for Indiko Plus was approved. The linearity study shows not linear trend but was likely due to a bad pipette and should be redone.
66

Utilisation des aptamères pour le dosage des petites molécules d'intérêt biologique / Use of aptamers for the determination of small molecules of biological interest

Chovelon, Benoit 21 December 2018 (has links)
La biochimie médicale est une discipline en constante évolution. L’enjeu du développement de nouvelles techniques est de permettre l’analyse à haut débit, de manière spécifique et à faible coût. Les techniques d’immunoanalyse omniprésentes en laboratoire de biologie médicale (LBM) répondent convenablement à ces critères, mais sont cependant perfectibles en ce qui concerne l’analyse des petites molécules d’intérêt biologique. L’objectif de ce travail est de développer des méthodes de dosage innovantes, pour les petites molécules, en utilisant les aptamères comme nouveaux outils de reconnaissance moléculaire. Il s’agit d’oligonucléotides fonctionnels simple brin, capables de reconnaître de manière spécifique une cible, isolés à partir d’une banque de candidats par une approche combinatoire in vitro nommée SELEX (Systematic Evolution of Ligands by Exponential Enrichment). Ils sont en concurrence avec les anticorps, en particulier dans le domaine du diagnostic. Nous avons dans un premier temps travaillé sur le développement de systèmes de dosage à double reconnaissance pour petite molécule, impliquant la formation d’un complexe boucle-boucle. L’adénosine et la théophylline ont tout d’abord servi de cibles modèles pour le développement en phase hétérogène d’une technique de dosage colorimétrique avec amplification enzymatique du signal. Le développement a ensuite été axé sur un analyte ayant un réel intérêt biologique, l’arginine-vasopressine. Le système a été développé en phase homogène en utilisant la technique d’anisotropie de fluorescence. L’application en milieu biologique a été facilitée par l’utilisation d’oligonucléotides non naturels en série L. Enfin nous avons décrit une méthode particulièrement innovante, sans marquage (« label-free »), permettant l’analyse des cibles de petite taille. Cette méthode basée sur l’utilisation du SYBR Green en solution couplée à la technique d’anisotropie de fluorescence, permet également l’étude des ligands de l’ADN. / Clinical chemistry is a constantly evolving discipline. The challenge of developing new techniques is to enable high throughput analysis specific and at low cost. Immunoassay techniques respond appropriately to these criteria, but are nevertheless perfectible with regards to the detection of small molecules of biological interest. The aim of this work is to develop innovative assay methods for small molecules of biological interest, using aptamers as alternative molecular recognition tools. They are single-stranded functional nucleic acids that are isolated from a very large library of candidates through an in vitro combinatorial approach (SELEX) for their ability to bind a peculiar species. They compete with antibodies, particularly in the area of diagnosis. First, we focused our work on the design of small molecule dual recognition assay systems that involved the formation of a loop-loop complex. Adenosine and theophylline served as model targets for the heterogeneous phase development of a colorimetric assay with enzymatic signal amplification. Subsequent works were performed by using arginine-vasopressin, an analyte with a real biological interest as target. A homogeneous phase fluorescence anisotropy detection system was constructed. Applications in complex matrix were facilitated by the use of non-natural L-oligonucleotides. Finally, a particularly innovative SYBR Green-based fluorescence anisotropy method, was reported allowing the detection of both small targets and DNA ligands.
67

New Advances in Capillary Electrophoresis for Biomonitoring in Population Health and Newborn Screening of Cystic Fibrosis

Mathiaparanam, Stellena January 2022 (has links)
Biological markers (i.e., biomarkers) are essential in clinical and epidemiological studies as they may provide mechanistic insights into the developmental origins of disease, as well as improve diagnostic testing and risk assessment for disease prevention. However, major challenges remain due to the lack of rapid yet selective analytical methods for high throughput screening that are also amenable to volume-restricted specimens. This thesis includes two major research themes that take advantage of capillary electrophoresis (CE) separations, including (1) the targeted analysis of urinary iodide and thiocyanate for assessment of nutritional adequacy and tobacco smoke exposures in the population, and (2) the discovery of new biomarkers in sweat specimens that may improve universal newborn screening programs for cystic fibrosis (CF) infants beyond impaired chloride transport. Chapter II examines the prevalence and risk factors associated with iodine deficiency in 24 h urine samples collected from 800 participants across four clinical sites in Canada as part of the Prospective Urban and Rural Epidemiological (PURE) study when using CE with UV detection in conjunction with sample self-stacking. Importantly, regional variations in iodine status were revealed with participants from Quebec City and Vancouver at greater risk for iodine deficiency than Hamilton and Ottawa. Overall, iodine supplement use, thyroxine prescription, urinary sodium excretion, and self-reported dairy intake were found to be protective factors against iodine deficiency. Chapter III applied a validated CE assay to measure urinary thiocyanate as a biomarker of tobacco smoke and dietary exposures in an international cohort of 1000 participants from the PURE study spanning 14 countries with varied income status, smoking habits, and diet quality. Current smokers residing in high-income countries had the highest extent of cyanide exposure indicative of greater harms from tobacco smoke compared to middle- and low-income countries after adjusting for smoking intensity and other covariates. Chapter IV introduces a rapid CE method with indirect UV detection to simultaneously measure sweat chloride and bicarbonate from presumptive CF infants’ residual sweat samples. Although bicarbonate did not provide clinical value in neonatal CF diagnosis, sweat chloride testing by CE may reduce test failure rates due to insufficient volumes from infants in a clinical setting. Lastly, Chapter V applied an untargeted strategy to characterize the sweat metabolome from presumptive CF infants when using multisegment injection-capillary electrophoresis-mass spectrometry (MSI-CE-MS). A panel of sweat metabolites were found to discriminate CF from non-CF (i.e., unaffected carriers) infants, including aspartic acid, glutamine, oxoproline, and pilocarpic acid, which also correlated with sweat chloride. The clinical utility of these sweat metabolites to prognosticate late-onset CF infants from indeterminate sweat chloride test results was also explored. In summary, this thesis contributes innovative separation methods for biomarker screening and discovery in clinical and epidemiological studies for the prevention and early treatment of human diseases that benefit from optimal nutrition. / Dissertation / Doctor of Philosophy (PhD)
68

PURIFICATION AND CHARACTERIZATION OF BLOOD ASPIRIN HYDROLASES

Zhou, Gang 06 June 2012 (has links)
No description available.
69

MASS SPECTROMETRY TO CHARACTERIZE SIGNIFICANT PROCESSES: FROM CHIRAL ENRICHMENT TO DISEASE METABOLISM

Rong Chen (9702269) 12 October 2022 (has links)
<p>Mass spectrometry (MS) can provide rapid, sensitive, and specific analysis, making it a valuable tool to characterize biomolecules, especially their dynamic changes when involved in significant processes.  Compared to other analytical techniques, which mostly focus on solution-phase or solid-phase characterization, MS enjoys a more general and efficient detection of gas-phase analytes since it ultimately measures abundances of bare ions in vacuum. This unique detection capability of MS has been demonstrated, in this dissertation, by characterizing the neutral serine octamer, a gas-phase amino acid cluster that has been detected by MS only so far. Besides its existence, the progress of chiral enrichment has also been monitored and quantified by MS during octamer formation. The acquired MS data is crucial to interpreting the mechanism of chiral enrichment achieved by serine octamer and might suggest its involvement in the prebiotic world to eventually achieve biohomochirality. The work also showcases the capability of detecting neutral compounds by MS, which breaks the stereotype that MS is exclusively an ion-based technique. </p> <p><br></p> <p>Besides process monitoring in the open air, MS also monitors the highly complicated metabolism processes inside biosamples, primarily benefiting from its excellent sensitivity, specificity, and throughput of ion detection. Since altered cellular metabolism is being recognized as a hallmark of cancer, MS is suitable for cancer diagnostics, whose performance of diagnosing glioma, a common brain cancer, has been tested.  Desorption electrospray ionization(DESI) has been used as it avoids sample preparation and allows direct characterization of raw tissue, therefore well suited for on-site analysis such as in the operating room. In short, we have applied intraoperative DESI-MS analysis on raw brain biopsies to provide glioma diagnostics within 5 min. Specifically, the molecular features revealed by MS are translated into pathological information of analyzed tissue, like genetic mutations and tumor concentrations, which is highly desired during surgeries to guide tumor resection and improve patient management. </p> <p><br></p> <p>Knowledge of diagnostic biomarkers is essential to the translation from MS data to pathology, which can be obtained by metabolic profiling using MS. Despite the tradeoff between comprehensive characterization and analysis time, we have extensively explored endogenous metabolites by using tandem MS and expedited analysis by avoiding the use of chromatography. After fast profiling, statistical analysis of all MS features has been applied to discover diagnostic markers to distinguish healthy brain tissue from cancerous tissue. DESI-MS methods have been developed to facilitate a simple and rapid characterization of these biomarkers in tissue for a smooth clinical transition. </p> <p><br></p> <p>However, the complete characterization of endogenous metabolites in a complicated biomixture, like tissue, is challenging, especially without the orthogonal separation provided by chromatography. This unmet demand calls for the development of novel MS scans to improve the metabolite coverage. For lipidomics by direct infusion MS, the MS scans used for lipid profiling have not been greatly expanded since its introduction. These conventionalMS scans only target one structural moiety of lipids and leave the rest unresolved, which limits the structure elucidation and biological interpretation of diagnostic lipids. We have introduced additional lipid scans that target both the lipid headgroup and one fatty acyl chain, leaving the other fatty acyl chain flexible. These scans with higher specificity can further alleviate the matrix effect by uncovering fewer ions in each scan and provide more structural information to support lipid identification. As a proof-of-concept, we have used them to profile both common phospholipids and the rarer ether lipids that display significant variations between healthy mice tissue and those with metabolic syndrome. The additional structural information provided by these scans ensures a clear message expressed by the disease metabolism and potentially indicates invention points and therapeutic candidates.</p>
70

Contrução do fago recombinante D29::gfp com potencial de aplicação nos testes de sensibilidade pela concentração inibitória mínima para o Mycobacterium spp. / Construction of the recombinant phage D29::gfp with application potential in sensitivity tests by the minimum inhibitory concentration for Mycobacterium spp.

Carbone, Paulo Henrique Lage 29 June 2007 (has links)
O objetivo desse trabalho foi construir o fago recombinante D29::gfp e testar a sua utilização como um agente revelador da viabilidade bacilar na determinação da concentração inibitória mínima (GIM) aos principais fármacos administrados no tratamento da tuberculose. O fago recombinante contém o promotor hsp70 e o gene da proteína verde fluorescente (gfp) e foi construído através da restrição pela Spe I em uma região intergênica próxima a extremidade coesiva direita no genoma do fago D29. O promotor hsp70 e gfp clonados no pYL GFP foram amplificados pela PCR utilizando iniciadores com sítios para Spe I. O DNA do fago D29 digerido pela Spe I foi ligado com o fragmento hsp 70- gfp empregando a T 4 DNA ligase e os produtos da reação de ligação foram transformados de acordo com o protocolo de encapsulamento. A infecção do M.smegmatis com esse fago recombinante induziu a expressão da proteína verde fluorescente (GFP). Para avaliar o uso do fago recombinante em teste de sensibilidade aos fármacos anti-tuberculose, 100 isolados clínicos foram testados quanto ao perfil de sensibilidade a isoniazida (H), rifampicina (R), estreptomicina (S) e etambutol (E), utilizando o método das proporções em Lowenstein-Jensen (L-J), técnica em microplaca com a resazurina (REMA) e técnica em microplaca com D29::gfp. Os resultados do REMA demonstraram que 30 isolados clínicos foram sensíveis à H e 58 (66 %) isolados clínicos foram resistentes, dentre os quais a CIM foi 1 &#181;g/mL ou maior para 41 (71 %). A CIM da R para 49 (56%) dos isolados clínicos resistentes foi de 0,5 &#181;g/mL para 17 (35%). A CIM da S para 33 (37%) dos isolados clínicos resistentes foi de 2 &#181;g/mL para 13 (40%) e CIM do E para 34 (39%) dos isolados clínicos resistentes foi de 16 &#181;g/mL ou maior para 19 (56%). A caracterização molecular pela PCR IS6110 identificou 88 isolados clínicos como M.tuberculosis e pelo PRA hsp65, sete isolados clínicos foram M.kansasii, quatro foram M.abscessus e um M.szulgai. Após empregar o fago recombinante como um agente indicador da viabilidade bacilar para testar a atividade dos fármacos anti-tuberculose conclui-se que a expressão da proteína verde fluorescente foi inespecífica e não reprodutiva, não justificando o seu uso para determinar a CIM para os principais fármacos administrados no tratamento da tuberculose. / The objective of this work was to construct the recombinant phage D29::gfp and to use this phage as an indicator agent of cell viability in a minimal inhibitory concentration (MIC) assay for the mains drugs used for tuberculosis treatment. The recombinant phage contains the mycobacteria-specific hsp70 promoter controlling the green fluorescent protein gene (gfp) and was constructed by Spe I restriction in the intergenic region next to the right cohesive termini of the D29 phage genome. An hsp 70 promoter and gfp previously cloned in p YL GFP was amplified by PCR using primers with Spe I sites. The Spe I-restricted D29 phage DNA was ligated with the hsp 70-gfp fragment using T4 DNA ligase and ligated product was transformed using the packing protocol. Infection of M.smegmatis with this recombinant phage indicated the expression of green f1uorescent protein (GFP). To use the recombinant phage for assaying the activity of anti-TB drugs, 100 clinical isolates was tested for susceptibility to isoniazid (H), rifampicin (R), streptomycin (S), and ethambutol (E) using both the proportion method on Lowenstein-Jensen (L-J) medium, resazurin microtiter assay plate (REMA), as well as a microplate assay using D29::gfp. The REMA plate method showed that 30 clinical isolates were susceptible to H and 58 (66%) clinical isolates were resistant, where the MICs were 1 &#181;g/mL or higher for 41 (71%). The R MICs for 49 (56%) resistant clinical isolates were 0,5 &#181;g/mL for 17 (35%). The S MICs for 33 (37%) resistant clinical isolates were 2 &#181;g/mL for 13 (40%) and E MICs for 34 (39%) resistant clinical isolates were 16 &#181;g/mL or higher for 19 (56%). Molecular characterization by PCR IS6110 showed that 88 clinical isolates were M.tuberculosis and by PRA hsp65 were seven clinical isolates were M.kansasii and four was M.abscessus, and one M.zulgai. After using the recombinant phage as an indicator agent of cell viability for assaying the activitity of anti-TB drugs we can conclude that the expression of green fluorescent protein was non-specific and not reproducible, rendering it not useful for the determination of the MIC of the principal drugs used for the treatment of tb.

Page generated in 0.1546 seconds