Brain stem auditory evoked potentials (BAEP) and somatosensory evoked potentials (SEP), recorded from subcutaneously placed electrodes in anesthetized rats, were used to detect the neurotoxic effects of acrylamide and 2,5-hexanedione. Sixty adult male rats were equally divided into four groups: acrylamide (20 mg/kg/day), 2,5-hexanedione (350 mg/kg/day), food restricted and control. Brain stem auditory evoked potentials and somatosensory evoked potentials were recorded on weeks 0,1,2 and 3 of treatment. SEP waveforms were considerably more variable than BAEP results. Mean latencies in the control, food restricted and acrylamide groups were similar for the entire three weeks. A nonsignificant increase was seen in the mean latencies in the 2,5-hexanedione group. Brain stem auditory evoked potential latencies recorded on the pretreatment week were compared to each successive week within a treatment group. The control group had small but statistically significant prolongations in the latencies of wave II on weeks 2 and 3, and latencies III and IV on week 3. Results from the food restricted group were not statistically different at any time. The acrylamide group had prolongations in latency II and IV by week 3 of treatment. Latencies of all waveforms from the 2,5-hexanedione group were significantly longer than pretreatment values on weeks 2 and 3. Mean latencies of the two consistently identified somatosensory evoked potential waves (Pl, Nl) recorded from the contralateral cortex on the pretreatment week were comparable to values reported in the literature. Brain stem auditory evoked potentials recorded from subcutaneously placed electrodes in anesthetized rats can detect the neurotoxic effects of acrylamide and 2,5-hexanedione. Lack of significant differences in the food restricted group indicates the observed effects in the groups receiving neurotoxicant were not related to weight loss. Differences in the control group were of small magnitude and variance and therefore may be statistically but not biologically significant. / Master of Science

Wetland wastewater treatment offers low-cost, energy efficient alternatives to conventional wastewater technologies. In this study, an artificial wetland was constructed at the City of Denton, Texas Pecan Creek Water Reclamation Plant to facilitate diazinon removal from treated effluent.

This study evaluated the effects of chlorinated effluent discharged from the City of Denton, Texas' wastewater treatment plant on Pecan Creek's fish and macroinvertebrate assemblages, and their recovery upon dechlorination. A baseline of ecological conditions was established while chlorine was present in the effluent (June 1993- October 1993), and was evaluated again after dechlorination with sulfur dioxide (October 1993-August 1994). In situ Asiatic clam and fathead minnow ambient toxicity tests, and fish and macroinvertebrate collections were used to establish this baseline for comparison to post-dechlorination results.

Dischargers to the Trinity River in North Texas were required to dechlorinate their effluents in 1990-91. Field surveys were conducted above and below an outfall to determine the response of resident immature insects and caged in situ juvenile Asiatic clams to chlorinated and dechlorinated effluent. Within six months after dechlorination began, insect community composition and C. fluminea survival significantly improved at stations below the outfall. Significantly lower clam growth within one mile below the dechlorinated effluent indicated the presence of non-chlorine toxicants. Effects from chlorinated and dechlorinated effluent exposure were comparable between Ceriodaphnia dubia lab tests and in situ C. fluminea.

Thesis (MSc)--University of Stellenbosch, 2004. / ENGLISH ABSTRACT: Agricultural environments are usually contaminated with mixtures of antropogenically introduced chemicals as a result of pesticide spraying, which can affect beneficial, nontarget soil invertebrates, such as earthworms negatively. Most studies on mixture toxicity have focused on interactions of chemicals with similar structures and mechanisms. However, chemical mixtures may occur as conglomerates of diverse structures and toxicological mechanisms in the environment. This study was aimed at assessing the effects of pesticides singly, and in a mixture, on earthworms, using lifecycle parameters (growth and reproduction) and biomarkers (neutral red retention (NRR) assay and acetylcholinesterase (AChE) inhibition) as endpoints. Thus, to determine whether any interactions occurred between the pesticides as shown by the measured endpoints. Another aim was to validate the use of the chosen biomarkers for assessing mixture toxicity. The pesticides used were from three groups: organophosphates, heavy metal-containing pesticides and pyrethroids. From these three groups, four of the most commonly used pesticides in the orchards and vineyards of the Western Cape, South Africa, were chosen, namely chlorpyrifos (organophosphate), azinphos-methyl (organophosphate), copper oxychloride (heavy metal-containing fungicide) and cypermethrin (pyrethroid). Earthworms were exposed in the laboratory to a range of concentrations of chlorpyrifos and copper oxychloride singly, and in 1:1 mixtures of these pesticides in artificial soil, for four weeks. After the exposure period, the biomass change was determined as measure of growth, and cocoon production, hatching success and number of hatchlings per cocoon were determined as measures of reproduction. Growth (biomass change) and reproduction (cocoon production) were affected by the highest concentration treatment (20mg/kg) of chlorpyrifos, but copper oxychloride and the mixture of the two pesticides showed no observable effects on lifecycle parameters. Dose related effects on NRR times were however determined for both pesticides and the mixture. Dose related effects on AChE activity were found for chlopyrifos and the mixture of the two pesticides, but not for copper oxychloride. Short-term exposures (48 hours) of earthworms to the following pesticides in artificial groundwater: chlorpyrifos, copper oxychloride, azinphos-methyl, cypermethrin, chlorpyrifos-copper oxychloride, chlorpyrifos -azinphos-methyl and chlorpyrifos-cypermethrin, were done followed by the determination of AChE inhibition. Dose related effects were exhibited on the AChE activity of earthworms exposed to chlorpyrifos, a mixture of chlorpyrifos and copper oxychloride, azinphos-methyl, and a mixture of azinphos-methyl and chlorpyrifos. Copper oxychloride, cypermethrin and the mixture of chlorpyrifos and cypermethrin had no effect on AChE activity. Earthworms died at the highest exposure concentration of the mixture of chlopyrifos and cypermethrin. Results have shown that although the pesticides did not cause observable effects on lifecycle parameters, there were effects at subcellular and biochemical level, as shown by the biomarkers. Mixtures of pesticides, in some instances, affected earthworms differently from their single components, indicating interactions between the pesticides in mixtures, as shown by the measured endpoints. The NRR assay proved to be a good general biomarker of soil contamination, and the AChE activity could also be a valuable tool in assessing the effects of organophosphate mixtures and mixtures of organophosphates and pesticides from other groups. / AFRIKAANSE OPSOMMING: Nie-teiken organismes, soos erdwurms, word negatief beïnvloed deur mengsels van antropogeniese chemikalieë in landbou-omgewings. Die meeste studies wat handel oor die toksisiteit van chemiese mengsels het tot dusver gefokus op chemikalieë van dieselfde aard en met dieselfde meganismes van werking. Mengsels van chemiese stowwe kan egter as konglomerate van 'n verskeidenheid strukturele eienskappe en met verskillende toksiese meganismes in die omgewing aangetref word. Tydens die studie is gepoog om die effekte van enkel pestisiede sowel as mengsels daarvan op erdwurms te bestudeer, deur van lewensloop kenmerke (groei en voortplanting) en biomerkers (neutraalrooi retensietyd - NNR en inhibisie van asetielcholienesterase -AChE) as eindpunte gebruik te maak. 'n Verdere doel van die studie was om vas te stel of daar enige wisselwerkings tussen die verskillende pestisiede plaasvind, soos aangetoon deur die gemete eindpunte, en verder ook om die gebruik van die gekose biomerkers as maatstawwe van mengseltoksisiteit te evalueer. Die pestisiede wat gebruik is, is van drie verskillende groepe afkomstig: organofosfate, swaarmetale en piretroiede. Van hierdie drie groepe is vier van die pestisiede wat vry algemeen in boorde en wingerde in die Weskaap, Suid-Afrika, gebruik word, geïdentifiseer. Hierdie stowwe is chlorpyrifos (organofosfaat), azinphos-metiel (organofosfaat), koperoksichloried (swaarmetaalbevattende fungisied) en sipermetrien (piretroied). Erdwurms is in die laboratorium aan 'n reeks konsentrasies van chlorpyrifos en koperoksichloried as enkel toksikante en as 1:1 mengsels in kunsmatige grond, vir vier weke blootgestel. Voor en na die blootstellingsperiode is die biomassa van die wurms, as maatstaf van groei, bepaal en kokonproduksie, uitbroeisukses en getal nakomelinge per kokon bepaal as maatstawwe van voortplantingsvaardigheid. Groei (biomassaverandering) en voortplanting (kokonproduksie) is beinvloed deur behandeling met die hoogste konsentrasie (20 mg/kg) chlorpyrifos, terwyl geen effek van koperoksichloried of die mengsel van hierdie twee pestisiede gevind is nie. Daar is gevind dat beide die pestisiede, enkel en in die mengsel, die NRR tye beinvloed het. Die AChE aktiwiteit is beinvloed deur chlorpyrifos en die mengsel, maar nie deur die koperoksichloried nie. Korttermyn blootstellings van erdwurms (48 uur), in kunsmatige grondwater, van erdwurms aan chlorpyrifos, koperoksichloried, azinphos-metiel en sipermetrien as enkel toksikante en mengsels van chlorpyrifos-koperoksichloried, chlorpyrifos-azinphos-metiel en chlorpyrifos-sipermetrien, is gedoen en gevolg deur die bepaling van AChE inhibisie. Koperoksichloried, cypermetrien en die chlorpyrifos-sipermetrien mengsel het geen waarneembare effek op die AChE aktiwiteit gehad nie ?????. Die erdwurms wat blootgestel is aan die hoogste konsentrasie in die mengsel van chlorpyrifos-sipermetrien het doodgegaan. Die resultate het getoon dat die pestisiede nie in die korttermyn die lewensloopkenmerke in enige waarneembare mate geaffekteer het nie maar daar was effekte op sellulêre en biochemiese vlakke soos aangetoon deur die biomerkers. Sommige mengsels van die pestisiede het die erdwurms verskillend van die enkelstowwe geaffekteer. Daar het dus wisselwerking tussen sommige van die pestisiede wat in mengsels aangewend is, plaasgevind, soos aangetoon deur die gemete eindpunte. Die NRR toets, as breë-spektrum biomerker was 'n goeie maatstaf van kontaminasie in grond en daar is aanduidings dat die AChE aktiwiteit, as 'n spesifieke biomerker, 'n nuttige maatstaf kan wees om die effekte van organofosfaatmengsels en mengsels van hierdie chemiese groep en die van ander chemikalieë aan te toon.

Chan, Wing Lung. / Thesis (M.D.)--Chinese University of Hong Kong, 2011. / Includes bibliographical references (leaves 111-130). / Abstracts in English and Chinese. / Title --- p.i / Acknowledgements --- p.ii / Table of Content --- p.iii / List of Tables --- p.viii / List of Figures --- p.xi / List of Graphs --- p.xii / Abbreviations --- p.xiv / Abstract --- p.xv / Abstract (Chinese) --- p.xvii / Chapter Chapter 1: --- General Introduction / Chapter 1.1 --- Diabetes Mellitus --- p.2 / Chapter 1.1.1 --- Type 1 diabetes mellitus --- p.3 / Chapter 1.1.2 --- Type 2 diabetes mellitus --- p.4 / Chapter 1.1.3 --- Gestational diabetes mellitus --- p.5 / Chapter 1.2 --- Diabetic Pregnancy --- p.6 / Chapter 1.2.1 --- Incidence of congenital malformations in diabetic pregnancy --- p.6 / Chapter 1.2.2 --- Long term complications in the infant of diabetic mother --- p.7 / Chapter 1.3 --- Hyperglycemia --- p.7 / Chapter 1.4 --- Oxidative Stress --- p.8 / Chapter 1.4.1 --- Oxidative stress and antioxidant enzymes --- p.8 / Chapter 1.4.2 --- Cellular function of oxidative stress --- p.9 / Chapter 1.4.3 --- Adverse effects of excess oxidative stress during embryogenesis --- p.9 / Chapter 1.5 --- Retinoic Acid --- p.10 / Chapter 1.5.1 --- Function of RA during embryonic development --- p.10 / Chapter 1.5.2 --- RA synthesis and degradation --- p.10 / Chapter 1.5.3 --- Mechanisms of retinoic acid signaling : --- p.12 / Chapter 1.5.4 --- Developmental genes regulated by RA --- p.12 / Chapter 1.6 --- Strategy of the Thesis --- p.14 / Chapter Chapter 2: --- General Materials and Methods / Chapter 2.1 --- Animals --- p.17 / Chapter 2.2 --- Induction of Diabetes --- p.17 / Chapter 2.3 --- Mating Methods --- p.18 / Chapter 2.3.1 --- Mice --- p.18 / Chapter 2.3.2 --- Rats --- p.18 / Chapter 2.4 --- Whole Mount In Situ Hybridization --- p.19 / Chapter 2.4.1 --- Synthesis of DNA plasmids and riboprobes --- p.19 / Chapter 2.4.1.1 --- Mini-scale preparation of plasmid DNA --- p.19 / Chapter 2.4.1.2 --- Linearization of DNA plasmid --- p.20 / Chapter 2.4.1.3 --- In vitro transcription and labeling --- p.21 / Chapter 2.4.2 --- Fixation and dehydration of embryos --- p.22 / Chapter 2.4.3 --- Hybridization with RNA probes --- p.23 / Chapter 2.4.4 --- Post-hybridization wash --- p.24 / Chapter 2.4.4.1 --- Pre-absorption of anti-DIG antibody --- p.25 / Chapter 2.4.4.2 --- Embryo powder preparation --- p.25 / Chapter 2.4.5 --- Post antibody wash and signal development --- p.25 / Chapter 2.5 --- Real-time Quantitative Reverse Transcription-Polymerase Chain Reaction (RT-PCR) --- p.26 / Chapter 2.5.1 --- Sample collection and storage --- p.26 / Chapter 2.5.2 --- Total RNA extraction --- p.27 / Chapter 2.5.3 --- Reverse transcription --- p.28 / Chapter 2.5.4 --- Quantitative real-time PCR --- p.28 / Chapter 2.5.5 --- Preparation of cDNA standards for real-time PCR --- p.29 / Chapter 2.6 --- RA-responsive Cell Line --- p.29 / Chapter 2.6.1 --- Cell culture --- p.30 / Chapter 2.6.2 --- Seeding 96-well plate with RA-responsive cells --- p.31 / Chapter 2.6.3 --- Applying samples to 96-well plate coated with RA-responsive cells --- p.31 / Chapter 2.6.4 --- β-galactosidase staining --- p.32 / Chapter 2.7 --- Separation of Protein Isoforms by Isoelectric Focusing (IEF) --- p.33 / Chapter 2.7.1 --- Preparing protein samples for IEF --- p.33 / Chapter 2.7.2 --- Isoelectric focusing --- p.33 / Chapter 2.7.3 --- IEF native gel staining --- p.34 / Chapter 2.7.4 --- Locating three retinaldehyde dehydrogenase (Raldh) isoforms --- p.35 / Chapter 2.8 --- In Vitro RA Synthesizing Reaction --- p.36 / Chapter Chapter 3: --- Effect of Maternal Diabetes on Retinoic Acid Synthesis in the Mouse Embryo / Chapter 3.1 --- Introduction --- p.38 / Chapter 3.2 --- Experimental Design --- p.41 / Chapter 3.3 --- Materials and Methods --- p.42 / Chapter 3.3.1 --- Sample collection --- p.42 / Chapter 3.3.1.1 --- Criteria for selecting embryos at the same developmental stage --- p.42 / Chapter 3.3.1.2 --- Sample collection for in situ hybridization --- p.42 / Chapter 3.3.1.3 --- Sample collection for real-time quantitative RT-PCR --- p.43 / Chapter 3.3.1.4 --- Sample collection for in vitro RA synthesizing reaction --- p.44 / Chapter 3.3.2 --- Statistical analyses --- p.45 / Chapter 3.4 --- Results --- p.46 / Chapter 3.4.1 --- "Comparison of the in situ expression pattern of Raldh 1, Raldh2 and Raldh3 between embryos of diabetic and non-diabetic mice" --- p.46 / Chapter 3.4.1.1 --- In situ hybridization patterns of Raldh 1 --- p.46 / Chapter 3.4.1.2 --- In situ hybridization patterns of Raldhl --- p.46 / Chapter 3.4.1.3 --- In situ hybridization patterns of Raldh3 --- p.47 / Chapter 3.4.2 --- "Comparison of the relative expression level of Raldh 1, Raldh2 and Raldh3 between embryos of diabetic and non-diabetic mice at different developmental stages" --- p.48 / Chapter 3.4.2.1 --- Relative expression levels of Raldh 1 --- p.50 / Chapter 3.4.2.2 --- Relative expression levels of Raldh2 --- p.50 / Chapter 3.4.2.3 --- Relative expression levels of Raldh3 --- p.51 / Chapter 3.4.3 --- Comparison of the in vitro RA synthesizing activity of Raldh 1 Raldh2 and Raldh3 enzymes between embryos of diabetic and non-diabetic mice at different developmental stages --- p.52 / Chapter 3.5 --- Discussion --- p.55 / Chapter Chapter 4: --- Effect of Hyperglycemia on Retinoic Acid Synthesis / Chapter 4.1 --- Introduction --- p.59 / Chapter 4.2 --- Experimental Design --- p.61 / Chapter 4.3 --- Materials and Methods --- p.64 / Chapter 4.3.1 --- Phlorizin treatment --- p.64 / Chapter 4.3.2 --- Whole rat embryo culture --- p.64 / Chapter 4.3.3 --- Preparation of rat serum --- p.65 / Chapter 4.3.4 --- In situ hybridization --- p.66 / Chapter 4.3.5 --- Real-time quantitative RT-PCR --- p.66 / Chapter 4.3.6 --- In vitro RA synthesizing reaction --- p.68 / Chapter 4.3.7 --- Statistical analyses --- p.68 / Chapter 4.4 --- Results --- p.70 / Chapter 4.4.1 --- "Comparison of the relative expression level of Raldh 1, Raldh2 and Raldh3 between embryos of diabetic and non-diabetic mice injected with phlorizin or suspension vehicle as control" --- p.70 / Chapter 4.4.2 --- Comparison of the in vitro RA synthesizing activity of different isoforms of Raldh enzymes between embryos of diabetic and non-diabetic mice injected with phlorizin or suspension vehicle as control --- p.73 / Chapter 4.4.3 --- In situ expression pattern of Raldh2 in rat embryos cultured in medium containing varying concentrations of D-glucose --- p.77 / Chapter 4.4.4 --- Relative expression levels of Raldh2 in rat embryos cultured in medium supplemented with varying concentrations of D-glucose --- p.78 / Chapter 4.4.5 --- In vitro RA synthesizing activity ofRaldh2 in rat embryos cultured in medium supplemented with varying concentrations of D-glucose --- p.79 / Chapter 4.5 --- Discussion : --- p.82 / Chapter Chapter 5: --- In Vitro Supplementation with RA Rescued Rat Embryos from Hyperglycemia-induced Congenital Malformations / Chapter 5.1 --- Introduction --- p.86 / Chapter 5.2 --- Experimental Design --- p.88 / Chapter 5.3 --- Materials and Methods --- p.89 / Chapter 5.3.1 --- Preparation of RA --- p.89 / Chapter 5.3.2 --- Supplementation of RA to rat embryos in culture --- p.89 / Chapter 5.3.3 --- Morphological scoring system --- p.90 / Chapter 5.3.4 --- Statistical analyses --- p.90 / Chapter 5.4 --- Results --- p.92 / Chapter 5.4.1 --- Supplementation with RA rescued embryos from hyperglyce- miainduced malformations --- p.92 / Chapter 5.5 --- Discussion --- p.101 / Chapter Chapter 6: --- Conclusion and Future Perspectives / Chapter 6.1 --- Conclusion and Future Perspectives --- p.106 / References --- p.111

A large number of weed seeds in the soil persist because of seed dormancy, and depletion of the seed bank through manipulation of seed dormancy has been suggested as one of the goals in weed control. This study was designed to investigate some of the factors which control dormancy and germination in Amaranthus retroflexus seeds. Germination studies were conducted at different temperatures, and either in continuous white light or in the dark. Higher temperatures increased germination and, although light interacted with temperature, its effect on germination varied with the temperature. In an attempt to determine changes in dormancy during dry storage, two lots of seeds were stored dry at different temperatures. Loss in dormancy increased with an increase in storage temperature and duration, but the time required for maximum germination varied according to the seedlot. Seeds germinated to higher percentages at high temperatures, but storage at higher temperatures and for prolonged duration resulted in seeds gaining the ability to germinate at lower temperatures. Changes in dormancy under field conditions were also examined. Seeds were buried at different depths and for different durations and they all lost viability with time, but this loss was greater in surface-sown and shallowly buried seeds. Dormancy was broken during cold periods and induced as warmer periods progressed. The effects of chemical stimulants on dormancy and germination were investigated. The response of seeds to ethephon and nitrate were assessed at different temperatures either at continuous white light or in the dark. Germination increased with the concentration of the chemicals, and a greater response was observed at lower temperatures. The response to light varied depending on temperature / Master of Science (Hons)

Includes examples of information booklets as appendices / Includes bibliographical references: p. 232-251 / xiv, 251 p. : photo. ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Thesis (Ph.D.)--University of Adelaide, Dept. of Community Medicine, 1994

Includes examples of information booklets as appendices Includes bibliographical references: p. 232-251

Two specific goals were addressed for this dissertation. First to investigate and identify the mechanistic profile of ketoconazole (KT)-induced hepatotoxicity by utilizing in vivo and in vitro approaches determining the mechanism of action for the hepatotoxicity incurred. To date, there has not been a mechanistic determination of the hepatotoxicity associated with KT in vivo. This dissertation evaluates the possible metabolic bioactivation of KT by cytochrome-P450 (CYP) or flavin-containing monooxygenases (FMO) resulting in covalent binding with hepatic macromolecules. The hypothesis of this study was to reveal whether covalent binding by the parent compound, KT, and/or reactive metabolites produces hepatic damage associated with increased serum alanine aminotransaminase (ALT) release and decreased hepatic glutathione (GSH). The first objective was determination of in vivo covalent binding in a dose-time response comparison in Sprague-Dawley (SD) rat ALT and GSH levels. Increased ALT and reduced hepatic GSH levels occurred. The second objective was an in vitro comparison of covalent binding with GSH levels utilizing SD microsomal protein with incubations of KT. Covalent binding decreased with added GSH to microsomal incubations. Thirdly, correlate in vivo with in vitro findings. Covalent binding of KT in vivo and in vitro occurred with increased doses and time. The final objective was to determine the bioactivation pathway utilizing heat inactivation and no NADPH in vitro. Covalent binding of KT decreased in the absence of NADPH and deactivation of FMO. The second goal was to determine and quantitate in vitro the presence of FMO isozymes in microsomes of the human intestinal duodenum, jejunum, ileum, and colon as well as the Caco-2 (HTB-37), epithelial intestinal (CCL-241) and colon (CRL1790) cell lines. The presence of FMO could result in a first-pass effect decreasing the bioavailability of soft nucleophiles or a toxicity effect due to inhibition or modulation of the enzyme from co-administration. To date, this is the first evaluation of FMO isoforms in human intestine and cell lines. Western blot techniques were utilized for detection of human FMO1, FMO3, and FMO5 using human FMO-expressed recombinant cDNA from a baculovirus system. / Graduation date: 2003