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  • 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.
21

IN-QUEST OF BIOMARKERS FOR ALZHEIMER’S DISEASE AND PHARMACOKINETIC PROFILE OF ANTICANCER AGENTS USING LC-MS IN HUMAN PLASMA

Mannem, Chandana January 2019 (has links)
No description available.
22

Vitamin D in Normal Breast Tissue Correlates to Early Breast Carcinogenesis

Lan, Shang-Lun January 2016 (has links)
No description available.
23

Aufbau und Anwendung einer Methode zur Identifizierung und Quantifizierung von Giften und deren Metaboliten in Blut und Haaren in der Systematischen Toxikologischen Analyse mittels Flüssigchromatographie-Quadrupol-Flugzeitmassenspektrometrie-Kopplung (LC-QTOF-MS)

Broecker, Sebastian 15 February 2012 (has links)
Die Systematische Toxikologische Analyse (STA) stellt auf Grund der großen Vielfalt und der ständigen Zunahme an toxikologisch relevanten Substanzen eine der größten Herausforderungen in der chemischen Analyse dar. In der vorliegenden Arbeit wurde daher die Eignung der Flüssigchromatographie in Kombination mit der Hybrid-Quadrupol-Flugzeitmassenspektrometrie (LC-QTOF-MS) für diesen Zweck untersucht. Dazu wurden eine Datenbank mit über 7360 und eine CID-Spektrenbibliothek mit mehr als 2720 toxikologisch relevanten Substanzen erstellt und geeignete Probenvorbereitungsmethoden entwickelt. Die Erprobung der Methoden erfolgte an dotierten Blut- und Haarproben. Hierbei zeigte sich, dass die Analyse im Auto-MS/MS-Modus (Messzyklen von MS- und MS/MS-Spektren) eine Identifizierung basischer Substanzen mittels CID-Spektren zwischen 0,5 und 2 ng/ml im Blut ermöglichte. Die Nachweisgrenzen der für 24 Wirkstoffe validierten Methode in Haaren lagen bei 3 bis 15 pg/mg. Die Eignung der LC-QTOF-MS zur STA von Haarproben wurde an 30 Drogentodesfällen und 60 Todesfällen mit bekannter chronischer Medikamenteneinnahme zu Lebzeiten sowie an 77 Blutproben nachgewiesen. Für die Suche nach Metaboliten wurde ein Metaboliten-Tool entwickelt. In der praktischen Anwendung auf Datenfiles von Blut- und Haarproben erwies sich das Tool als wertvolles Hilfsmittel zur Identifizierung unbekannter Peaks und zur Bestätigung von Suchergebnissen in der Datenbank. Zur automatischen Konzentrationsabschätzung identifizierter Substanzen wurde ein Tool „Estimate Concentration“ geschaffen. Die Überprüfung des Verfahrens an realen Blut- und Haarproben durch Vergleich mit HPLC-DAD- und GC-MS-Ergebnissen wies eine gute Übereinstimmung der Konzentrationen auf. Insgesamt zeigten die Untersuchungen, dass die LC-QTOF-MS zurzeit die am besten geeignete Methode für die STA darstellt. Auch bei einem erst später aufkommenden Verdacht kann eine gezielte Suche in dem bereits gemessenen Datenfile durchgeführt werden. / Due to the large variety and the steady increase of toxicologically relevant substances, systematic toxicological analysis (STA) is one of the most difficult tasks in analytical chemistry and, therefore, a steady topic of research and methodical improvement. For this reason, the suitability of liquid chromatography in combination with hybrid quadrupole time-of-flight mass spectrometry (LC-QTOF-MS) for STA was investigated. For this purpose, a database of more than 7360 and a CID spectra library of more than 2720 toxicologically relevant substances and suitable methods for sample preparation were developed. The application was evaluated at spiked blood and hair samples. It was found that the analysis in Auto-MS/MS mode (alternating measurement cycles of MS and MS/MS spectra) allowed substance identification in blood using CID spectra between 0.5 and 2 ng/ml for basic substances. The detection limits of the validated method in hair ranged from 3 to 15 pg/mg for 24 drugs. The suitability of LC-QTOF-MS for STA was tested for hair samples from 30 drug-related death cases and from 60 death cases with known chronic medication as well as for 77 blood samples. For the search of metabolites, a metabolite tool was developed. In the practical application to data files from blood and hair samples, the tool proved to be very helpful for identification of unknown peaks and for confirmation of results obtained only from the database without CID spectra. A tool "Estimate Concentration" was created for automatic estimation of concentrations of identified substances. The application to real blood and hair samples and the comparison of the concentrations with results from HPLC-DAD and GC-MS showed good agreement. Overall, these investigations showed that LC-QTOF-MS is currently the most favorable method for STA. Because of the comprehensive registration of all substances in a sample, the data files can be checked for the presence of certain poisons even later without new measurements.
24

Ethnobotany, Pharmacology, and Metabolomics of Antidiabetic Plants used by the Eeyou Istchee Cree, Lukomir Highlanders, and Q’eqchi’ Maya

Ferrier, Jonathan 15 January 2014 (has links)
A study was undertaken of plants used for treatment of diabetic symptoms by traditional healers of the Eeyou Istchee Cree (Canada), Lukomir Highlanders (Bosnia & Herzegovina), and Q’eqchi’ Maya (Belize). All antidiabetic plants were ranked by syndromic importance value (SIV) based on 15 symptoms, all of which were recognized by the Cree and Maya and 8 by the Highlanders. The Cree used only 18 species, the Highlanders 41, and the Maya 150, numbers which reflect the diversity of flora in their region. Vaccinium (Ericaceae) was one of the few genera in all three regions and the only consensus genus between the Cree and Highlander study sites. The Q’eqchi’ Maya ethnobotany did not present any cross-cultural consensus genera with Cree or Highlander medicinal plants, perhaps due to major biogeographic differences. In ethnopharmacological studies, Vaccinium species and Q’eqchi’ antidiabetic plants were tested in an assay relevant to diabetes, the advanced glycation endproduct (AGE) inhibition assay. Boreal and tropical Vaccinium species were potent inhibitors of AGEs and demonstrated concentration dependent inhibition, with a half maximal inhibitory concentration (IC50) range of 5.93–100 µg/mL. Phenolic content ranged from 80.3 to 201 µg/mL in boreal samples and from 1470 to 2170 µg/mL in tropical samples. Tropical species have a greater phenolic content and AGE inhibition. Seven Q’eqchi’ antidiabetic plant species were tested and all plant extracts showed AGE-inhibition. The IC50s ranged from 40.8 to 733 µg/mL, and the most active was Tynanthus guatemalensis Donn.. Tynanthus guatemalensis IC50 was about fives times greater (less active) than the mean ± SE IC50 reported for six tropical Vaccinium species of Vaccinium (8.77 ± 0.79 μg/mL). The highest consensus and most active Maya antidiabetic plant, Tynanthus guatemalensis Donn. Sm. was discovered to be an important plant recorded in archeological artifacts from the Late Classic Maya period (~750 CE). Ancient Maya used a cross shaped sign (k’an glyph) as a decorative element on Late Classic polychrome vessels and murals. The sign was believed to be the xylem template for a plant used as a flavouring in cacao drinks. However, the plant was incorrectly identified in the literature as Pimenta dioica (L.) Merr. (common name: Allspice) based on a common name and aromatic plant quality – not from a botanical voucher specimen. Pimenta dioica wood does not have a cross shape visible in the xylem but a unique character visible after a cross section of T. guatemalensis, is the xylem's cross shape organization. Wood of T. guatemalensis' also has an "allspice" aroma. Tynanthus guatemalensis is most likely the true botanical template behind the ancient Maya k’an glyph and this finding would show the continuity of use of this medicinal plant from ancient to modern times. Vaccinium was selected for an in depth phytochemical analysis using modern metabolomic methods. Nuclear magnetic resonance (1H NMR) was used to evaluate leaf extract spectra to provide information on (1) the taxonomic identity and (2) quantities of bioactive metabolites across multiple sites. Spectra clearly differentiated leaf samples of V. angustifolium, V. boreale, V. corymbosum, V. macrocarpon, V. myrtilloides, V. myrtillus, V. ovalifolium, and V. uliginosum according to generic, subgeneric, specific, phenotypic circumscriptions. Quantification of chlorogenic acid and hyperoside were replicated with a method that is highly reproducible across multiple sites with different NMR equipment. This methodology provides an important new approach to taxonomy and quality control for plants and natural health products.
25

Ethnobotany, Pharmacology, and Metabolomics of Antidiabetic Plants used by the Eeyou Istchee Cree, Lukomir Highlanders, and Q’eqchi’ Maya

Ferrier, Jonathan January 2014 (has links)
A study was undertaken of plants used for treatment of diabetic symptoms by traditional healers of the Eeyou Istchee Cree (Canada), Lukomir Highlanders (Bosnia & Herzegovina), and Q’eqchi’ Maya (Belize). All antidiabetic plants were ranked by syndromic importance value (SIV) based on 15 symptoms, all of which were recognized by the Cree and Maya and 8 by the Highlanders. The Cree used only 18 species, the Highlanders 41, and the Maya 150, numbers which reflect the diversity of flora in their region. Vaccinium (Ericaceae) was one of the few genera in all three regions and the only consensus genus between the Cree and Highlander study sites. The Q’eqchi’ Maya ethnobotany did not present any cross-cultural consensus genera with Cree or Highlander medicinal plants, perhaps due to major biogeographic differences. In ethnopharmacological studies, Vaccinium species and Q’eqchi’ antidiabetic plants were tested in an assay relevant to diabetes, the advanced glycation endproduct (AGE) inhibition assay. Boreal and tropical Vaccinium species were potent inhibitors of AGEs and demonstrated concentration dependent inhibition, with a half maximal inhibitory concentration (IC50) range of 5.93–100 µg/mL. Phenolic content ranged from 80.3 to 201 µg/mL in boreal samples and from 1470 to 2170 µg/mL in tropical samples. Tropical species have a greater phenolic content and AGE inhibition. Seven Q’eqchi’ antidiabetic plant species were tested and all plant extracts showed AGE-inhibition. The IC50s ranged from 40.8 to 733 µg/mL, and the most active was Tynanthus guatemalensis Donn.. Tynanthus guatemalensis IC50 was about fives times greater (less active) than the mean ± SE IC50 reported for six tropical Vaccinium species of Vaccinium (8.77 ± 0.79 μg/mL). The highest consensus and most active Maya antidiabetic plant, Tynanthus guatemalensis Donn. Sm. was discovered to be an important plant recorded in archeological artifacts from the Late Classic Maya period (~750 CE). Ancient Maya used a cross shaped sign (k’an glyph) as a decorative element on Late Classic polychrome vessels and murals. The sign was believed to be the xylem template for a plant used as a flavouring in cacao drinks. However, the plant was incorrectly identified in the literature as Pimenta dioica (L.) Merr. (common name: Allspice) based on a common name and aromatic plant quality – not from a botanical voucher specimen. Pimenta dioica wood does not have a cross shape visible in the xylem but a unique character visible after a cross section of T. guatemalensis, is the xylem's cross shape organization. Wood of T. guatemalensis' also has an "allspice" aroma. Tynanthus guatemalensis is most likely the true botanical template behind the ancient Maya k’an glyph and this finding would show the continuity of use of this medicinal plant from ancient to modern times. Vaccinium was selected for an in depth phytochemical analysis using modern metabolomic methods. Nuclear magnetic resonance (1H NMR) was used to evaluate leaf extract spectra to provide information on (1) the taxonomic identity and (2) quantities of bioactive metabolites across multiple sites. Spectra clearly differentiated leaf samples of V. angustifolium, V. boreale, V. corymbosum, V. macrocarpon, V. myrtilloides, V. myrtillus, V. ovalifolium, and V. uliginosum according to generic, subgeneric, specific, phenotypic circumscriptions. Quantification of chlorogenic acid and hyperoside were replicated with a method that is highly reproducible across multiple sites with different NMR equipment. This methodology provides an important new approach to taxonomy and quality control for plants and natural health products.

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