Eastern Sand Darter (Ammocrypta pellucida) is listed as Threatened under the Canadian Species at Risk Act. Canadian populations are declining primarily due to the siltation of sandy depositional areas, the preferred habitat of the species. Little other relevant biological information is available for most Canadian populations and only limited information is available for populations in the United States. To supplement the paucity of information, this study collected biological information on A. pellucida during field surveys in 2006- 2007 from 10 sites located around the Big Bend Conservation Area in the lower Thames River, Ontario, Canada. Collected data were used to estimate critical life history traits including: longevity, fecundity, clutch size and number, growth, survival, age-at-first-maturity and cohort age structure. Longevity was 3+ years, with age-at-first-maturity being 1+ for both sexes. A minimum of 2 clutches, were laid per year with an average clutch size of 71 eggs. Average density within in the study area was 0.36 ± 0.11 A. pellucida/m². Quantitative comparison of lower Thames River biological information with a more southerly A. pellucida population in the Little Muskingum River, Ohio, demonstrated little latitudinal variation between the populations. Data comparison suggests that localized environmental factors are affecting biological characteristics, in particular water temperature that may be controlled by differences in riparian cover and/or groundwater input. Field derived life history information was used to create a Leslie matrix model which was used for population viability analysis. Perturbation analyses of reproductive scenarios involving changes in clutch numbers and size and age-at-first maturity found large variations in the finite rate of population growth. Elasticity analyses further indicated that 0+ survival and 1+ fertility were the limiting life history parameters. Thus allowing fish to survive until first reproduction would have the largest overall impact on improving population viability. Inclusion of environmental stochasticity in the model facilitated estimation of extinction probabilities in the range of 0.13 to 0.21 within 100 years. Based on the above, it is recommended that management activities for protection and restoration of A. pellucida focus on habitat protection of nursery and spawning areas.

Cytotoxicity of Multi-Purpose Solutions (MPS) is commonly tested on cells using diluted MPS or extracts from MPS soaked contact lenses. There is evidence that lens type will affect uptake and release of compounds contained in MPS. To assess the cytotoxicity of agents contained in MPS that would be released by contact lens, an in vitro “onlay” model was used, whereby MPS soaked silicone hydrogel lenses were directly set onto a confluent monolayer of corneal cells. Chapter 4 describes the impact of MPS released from contact lenses on immortalized human corneal epithelial cells. MPS-soaked lens interactions with cells were characterized by studying cell viability, cell adhesion and caspase assays. In Chapter 5, mechanisms of cell death induced by exposure to MPS from contact lenses were determined through evaluation of apoptotic markers, such as activation of caspase 3 and 9. In Chapter 6, the impact of the physical properties of silicone hydrogel lenses, specifically surface treatments, on cytotoxicity of MPS were investigated. The development of methods for characterizing the release of MPS from lenses, using absorbance spectra, is also described. The results indicate that exposure to contact lenses soaked in Opti-Free Express (OFX) and ReNu not only induces cell death in vitro, but also has an adverse effect on adhesion phenotype, suggesting that the remaining cells may have a compromised epithelial structure. Borate- buffered MPS were found to be more cytotoxic than phosphate-buffered base solutions. Investigation of the mechanisms of cell death revealed that ReNu and OFX induced corneal epithelial cell death in vitro using different pathways, whereby ReNu induced a necrotic pathway while OFX-induced cell death was mediated by the intrinsic pathway of apoptosis. The in vitro model was also able to identify differences between silicone hydrogels with different surface treatments: the different surface treatments and chemistries of silicone hydrogels lens will affect the release profile of MPS and hence their potential cytotoxicity. By investigating the induction of cell death processes by solution-lens combinations in vitro, we aim to prevent potential adverse effects in the cornea, which may ultimately compromise various visual and barrier functions. The findings indicate the wealth of information in vitro cytotoxicity testing can provide when evaluating the toxicological profile of MPS.

Eastern Sand Darter (Ammocrypta pellucida) is listed as Threatened under the Canadian Species at Risk Act. Canadian populations are declining primarily due to the siltation of sandy depositional areas, the preferred habitat of the species. Little other relevant biological information is available for most Canadian populations and only limited information is available for populations in the United States. To supplement the paucity of information, this study collected biological information on A. pellucida during field surveys in 2006- 2007 from 10 sites located around the Big Bend Conservation Area in the lower Thames River, Ontario, Canada. Collected data were used to estimate critical life history traits including: longevity, fecundity, clutch size and number, growth, survival, age-at-first-maturity and cohort age structure. Longevity was 3+ years, with age-at-first-maturity being 1+ for both sexes. A minimum of 2 clutches, were laid per year with an average clutch size of 71 eggs. Average density within in the study area was 0.36 ± 0.11 A. pellucida/m². Quantitative comparison of lower Thames River biological information with a more southerly A. pellucida population in the Little Muskingum River, Ohio, demonstrated little latitudinal variation between the populations. Data comparison suggests that localized environmental factors are affecting biological characteristics, in particular water temperature that may be controlled by differences in riparian cover and/or groundwater input. Field derived life history information was used to create a Leslie matrix model which was used for population viability analysis. Perturbation analyses of reproductive scenarios involving changes in clutch numbers and size and age-at-first maturity found large variations in the finite rate of population growth. Elasticity analyses further indicated that 0+ survival and 1+ fertility were the limiting life history parameters. Thus allowing fish to survive until first reproduction would have the largest overall impact on improving population viability. Inclusion of environmental stochasticity in the model facilitated estimation of extinction probabilities in the range of 0.13 to 0.21 within 100 years. Based on the above, it is recommended that management activities for protection and restoration of A. pellucida focus on habitat protection of nursery and spawning areas.

Cytotoxicity of Multi-Purpose Solutions (MPS) is commonly tested on cells using diluted MPS or extracts from MPS soaked contact lenses. There is evidence that lens type will affect uptake and release of compounds contained in MPS. To assess the cytotoxicity of agents contained in MPS that would be released by contact lens, an in vitro “onlay” model was used, whereby MPS soaked silicone hydrogel lenses were directly set onto a confluent monolayer of corneal cells. Chapter 4 describes the impact of MPS released from contact lenses on immortalized human corneal epithelial cells. MPS-soaked lens interactions with cells were characterized by studying cell viability, cell adhesion and caspase assays. In Chapter 5, mechanisms of cell death induced by exposure to MPS from contact lenses were determined through evaluation of apoptotic markers, such as activation of caspase 3 and 9. In Chapter 6, the impact of the physical properties of silicone hydrogel lenses, specifically surface treatments, on cytotoxicity of MPS were investigated. The development of methods for characterizing the release of MPS from lenses, using absorbance spectra, is also described. The results indicate that exposure to contact lenses soaked in Opti-Free Express (OFX) and ReNu not only induces cell death in vitro, but also has an adverse effect on adhesion phenotype, suggesting that the remaining cells may have a compromised epithelial structure. Borate- buffered MPS were found to be more cytotoxic than phosphate-buffered base solutions. Investigation of the mechanisms of cell death revealed that ReNu and OFX induced corneal epithelial cell death in vitro using different pathways, whereby ReNu induced a necrotic pathway while OFX-induced cell death was mediated by the intrinsic pathway of apoptosis. The in vitro model was also able to identify differences between silicone hydrogels with different surface treatments: the different surface treatments and chemistries of silicone hydrogels lens will affect the release profile of MPS and hence their potential cytotoxicity. By investigating the induction of cell death processes by solution-lens combinations in vitro, we aim to prevent potential adverse effects in the cornea, which may ultimately compromise various visual and barrier functions. The findings indicate the wealth of information in vitro cytotoxicity testing can provide when evaluating the toxicological profile of MPS.

The effects of 1 min 4 hr exposures to mercuric chloride (HgCl2), methyl mercuric chloride (CH3HgCl), p-chloromercuribenzoate (p-CMB) and ethylmercurithiosalicylate (TMS) on cell viability and kinetics of cell death, microtubules, F-actin, CD3 receptor expression, protein tyrosine phosphorylation (PTyr-P), intracellular calcium [Ca2+]i and responses to polarized signals in YAC-1 lymphoma cells were investigated. We hypothesized that immunotoxic effects of HgCl2 (Hg2+) are initiated by global receptor triggering, accompanied by increased protein tyrosine phosphorylation (PTyr-P) and down-regulation of the T-cell receptor (TCR). As a polychloride anion with poor lipid solubility, inorganic Hg2+ may produce effects at the outer cell membrane before significant intracellular accumulation, loss of microtubule integrity (a sensitive target) and activation of cell death through apoptotic pathways. The organomercurial compound p-CMB is likewise thought to penetrate membranes slowly as a result of ionization. In contrast, the highly lipid-soluble organomercurial compounds CH3HgCl and TMS were expected to reduce responses to polarized stimuli only in conjunction with and not prior to loss of microtubule integrity and the onset of necrotic cell death. <p>Two general patterns of effects were observed. In HgCl2-treated YAC-1 cells, inhibition of responses to polarized stimuli preceded loss of microtubules and onset of cell death. Effects on polarized stimuli were preceded by a transient Ca2+ signal; however, this Ca2+ signal appeared abortive, accompanied by a paradoxic decrease in PTyr-P and partial down-regulation of CD3 receptors. Responses to polarised stimuli were inhibited prior to extensive loss of microtubule staining, indicating effects preceded cytosolic Hg2+ accumulation. HgCl2 exposure was followed rapidly by necrotic cell death. <p>Similarly, p-CMB-treated YAC-1 cells failed to respond to polarized stimuli before effects on microtubules or loss of viability, and proceeded rapidly to late apoptosis; however, a transient Ca2+ signal and progressive loss of F-actin preceded effects in all other assays and may account for loss of polarized responses. <p>In CH3HgCl- and TMS-treated YAC-1 cells, CD3 receptor expression, [Ca2+] and PTyr-P were increased immediately, along with loss of microtubules. These reductions preceded inhibition of polarized signaling responses and seemed to indicate a general loss of cellular homeostasis not seen in HgCl2- and p-CMB-treated cells; loss of homeostasis did not necessarily produce simultaneous loss of viability, as TMS-treated cells remained viable for 30 min while CH3HgCl-treated cells became apoptotic within 1 min. Nonetheless, the YAC-1 cells proceeded to cell death more slowly, remaining early apoptotic after 4 hr, when almost all HgCl2- and p-CMB-treated cells were necrotic. These findings indicate the two groups of mercury compounds may alter responses to polarized stimuli and induce cell death by distinct pathways, one involving an apparently abortive signal and the other mediated by much more profound disruption of cellular homeostasis. Within the larger patterns there are further differences between the effects produced by each Hg compound, likely reflecting the combined influence of pharmacokinetic and dynamic factors governing access to and interactions with different cellular targets leading to cell death. These distinct targets may in turn be reflected in the different immune effects produced by these compounds <i>in vivo</i>.

Of the seven pelican species found world wide, only the Great White Pelican (Pelecanus onocrotalus) and the Pink-backed Pelican (P. rufescens) are found in Africa. The KwaZulu-Natal province of South Africa supports only one breeding site for each of these species, and both sites represent the southern most breeding colonies for the two species in the eastern region of Africa. These nesting sites fall within the Greater St Lucia Wetland Park, and are afforded a degree of protection, but the same is not true for their foraging and dispersal ranges, and this is a cause for concern. Considerable amounts of data have been collected relating to the status, distribution and breeding efforts of these two species in north eastern KwaZulu-Natal. These data have been collected in a variety of ways by a large number of people. Part of this work represents an attempt to collate and summarise these data to produce an estimation of the status, distribution and breeding success of these species, and to evaluate any trends in their demography. For this south eastern region of Africa I estimated the population for the Great White Pelican to range between 6000 and 9000 individuals, and the Pink-backed Pelican to range between 600 and 900 individuals. Pelicans are highly mobile birds, and this allows them to move considerable distances when they forage, disperse or migrate. They are also long-lived birds with few natural predators. The two pelican species in south eastern Africa have been poorly studied and little is known about their movements, population dynamics and causes of mortality. Habitat change poses a potential threat to pelicans in north eastern KwaZulu-Natal, and habitat loss could drive these species out this region to areas north of South Africa. Much of this north eastern region of KwaZulu-Natal is under threat, mainly through the actions of man. Many areas are naturally unsuitable for pelican foraging, while others are vital to the survival of both species. This study includes an attempt to assess the movements of these two species in south eastern Africa, and to assess the relative importance and condition of the potential pelican habitat in the north eastern KwaZulu-Natal region, focusing particularly on Lake St Lucia and the Pongolo River floodplain. All this is necessary to produce a baseline from which long term predictions of potential pelican species survival can be made. In the absence of documented life tables and environmental variability data, a range of parameters was modelled to generate population viability analyses to simulate possible scenarios. These extinction models show the outcomes of both the deterministic and the stochastic processes. An attempt was also made to identify the factors that impact most severely on the persistence of these two species. The models were most sensitive to variation in survivorship in the first year of life and to the frequency of catastrophes. Changes in these parameters had the greatest effect on extinction risk. In January 2004 Lake St Lucia was reduced to a fraction of its normal capacity as a result of a severe drought in this region of KwaZulu-Natal. After rains in the area the lake level rose and then fluctuated considerably over the next 24 months. During this time the mouth of the estuary into the sea was closed. Great White Pelican numbers and lake levels were monitored throughout this period. This part of the study relates the changes in population numbers to the lake conditions, and highlights the importance of the lake to this avian species. It uses lake levels as a proxy for the conditions of wetlands in the Lake St Lucia region. It also addresses the implications of these relationships to the management strategy of the lake and the conservation of some avifauna. To identify conservation concerns for the Great White and Pink-backed Pelicans it was necessary to generate these baseline estimations. Although much of this information is uncertain for these two species, an attempt has been made here to predict the persistence of these species in north eastern KwaZulu-Natal and to highlight the conservation issues related to their future. / Thesis (M.Sc.)-University of KwaZulu-Natal, Pietermaritzburg, 2006

Sicyos deppei G. Don (Cucurbitaceae) is an invasive monoic annual tendril-bearing vine; it is endemic to Mexico, adapted to the rainfall cycle (June through the end of September) and produces spiny, single seeded fruits. Under serious infestation conditions, S. deppei grows extensively, covering native plants, crops and tree trunks. This study determined the breeding system and pollinators of S. deppei growing in three study sites at urban gardens and disturbed sites at the Campus of the Universidad de las Américas, Puebla in the city of San Andrés Cholula, Puebla (Mexico). Each female inflorescence had an average of 17 flowers at the three study sites. As a step prior to experiments, the timing for stigma receptiveness and pollen viability was determined with the Peroxtesmo KO test (PKO) and Diaminobenzidine test (DAB),respectively. Stigmas of female flowers reach maximum receptivity when flowers are at anthesis; receptivity decreases as the flower reaches the succeeding floral stages. Viability of pollen grains increases with flower development; viabilitypercentages at early stages of floral development are very low, as opposed to the higher percentages of pollen viability found in flowers at anthesis and following developmental stages. Breeding systems were tested for xenogamy and geitonogamy by hand pollinating female flowers. Breeding systems results demonstrated that S. i deppei has a mixed-mating system, being able to set fruit and seed when pollinated with pollen from different plants and from pollen of the same plants. The pollinators were determined with the single-visit method. The diversity of floral visitors in this study was low; the most effective pollinator for S. deppei in this study was Apis mellifera. Throughout the rainy season, this study also described the phenology of S. deppei at the plant and flower level, as well as total plant length. Each stage of development in male and female flowers lasts one day. At the end of the rainy season (N2010) individual plants measured between 947 and 270 cm. / CONACYT, NSERC-CANPOLIN

The main goal of this dissertation was to assess prospectively the value of two cardiovascular magnetic resonance methodises (the transmural extent of an late gadolinium enhancement and the contractile reserve during low dose dobutamine administration) as predictors of left ventricular segmental and global functional recovery in patients with left ventricular systolic dysfunction undergoing surgical or percutaneous revascularisation. Taking into account previous studies, revascularisation of the viable myocardium results in an improvement of patient’s symptoms and prognosis. This finding emphasized the need for and importance of noninvasive tests to quantify the amount of viable myocardium in patients with left ventricular dysfunction in order to define the optimal management strategy. On the basis of the research described in the dissertation, the diagnostic value of different cardiovascular magnetic resonance based viability prediction methods was assessed. The superiority of combined viability prediction model incorporating an late gadolinium enhancement and the contractile reserve during low dose dobutamine administration was confirmed. The optimal predictors of the significant improvement of left ventricular ejection fraction were found: the percentage of viable segments from all dysfunctional and revascularised segments in a patient and the absolute value of left ventricular ejection fraction measured during low dose dobutamine administration. On the basis of the... [to full text] / Disertacijoje nagrinėta dviejų magnetinio rezonanso metodikų (vėlyvojo kontrastinės medžiagos kaupimo transmuralumo bei mažų dobutamino dozių sukeliamo miokardo kontraktilinio rezervo) bei šių metodikų derinio vertė, prognozuojant bendrosios bei segmentinės kairiojo skilvelio funkcijos atsistatymą po revaskuliarizacijos (perkutaninės vainikinių arterijų intervencijos ar vainikinių arterijų apeinamųjų jungčių suformavimo operacijos), pacientams, turintiems išeminės kilmės kairiojo skilvelio sistolinę disfunkciją. Kadangi yra nustatyta, jog sėkminga gyvybingo miokardo revaskuliarizacija pagerina kairiojo skilvelio sistolinę disfunkciją turinčių pacientų simptomus bei prognozę, todėl gyvybingo miokardo nustatymas yra svarbus, siekiant parinkti optimalią tokių pacientų gydymo taktiką. Disertacijoje aprašomo tyrimo pagalba buvo nustatyta širdies magnetinio rezonanso vertė, prognozuojant miokardo bendrosios bei segmentinės kontrakcijos atsistatymą bei pagrįsta vėlyvojo kontrastinės medžiagos kaupimo transmuralumo bei mažų dobutamino dozių sukeliamo kontraktilinio rezervo nustatymo metodikų derinimo nauda. Disertacijoje aptarti optimalūs reikšmingo bendrosios kairiojo skilvelio sistolinės funkcijos pagerėjimo prognostiniai rodikliai: gyvybingų segmentų procentas nuo visų išeityje disfunkcinių bei revaskuliarizuotų paciento segmentų bei absoliuti kairiojo skilvelio išstūmimo frakcija, išmatuota mažų dobutamino dozių skyrimo metu. Disertacijos rezultatų pagrindu buvo sukurtas... [toliau žr. visą tekstą]

Disertacijoje nagrinėta dviejų magnetinio rezonanso metodikų (vėlyvojo kontrastinės medžiagos kaupimo transmuralumo bei mažų dobutamino dozių sukeliamo miokardo kontraktilinio rezervo) bei šių metodikų derinio vertė, prognozuojant bendrosios bei segmentinės kairiojo skilvelio funkcijos atsistatymą po revaskuliarizacijos (perkutaninės vainikinių arterijų intervencijos ar vainikinių arterijų apeinamųjų jungčių suformavimo operacijos), pacientams, turintiems išeminės kilmės kairiojo skilvelio sistolinę disfunkciją. Kadangi yra nustatyta, jog sėkminga gyvybingo miokardo revaskuliarizacija pagerina kairiojo skilvelio sistolinę disfunkciją turinčių pacientų simptomus bei prognozę, todėl gyvybingo miokardo nustatymas yra svarbus, siekiant parinkti optimalią tokių pacientų gydymo taktiką. Disertacijoje aprašomo tyrimo pagalba buvo nustatyta širdies magnetinio rezonanso vertė, prognozuojant miokardo bendrosios bei segmentinės kontrakcijos atsistatymą bei pagrįsta vėlyvojo kontrastinės medžiagos kaupimo transmuralumo bei mažų dobutamino dozių sukeliamo kontraktilinio rezervo nustatymo metodikų derinimo nauda. Disertacijoje aptarti optimalūs reikšmingo bendrosios kairiojo skilvelio sistolinės funkcijos pagerėjimo prognostiniai rodikliai: gyvybingų segmentų procentas nuo visų išeityje disfunkcinių bei revaskuliarizuotų paciento segmentų bei absoliuti kairiojo skilvelio išstūmimo frakcija, išmatuota mažų dobutamino dozių skyrimo metu. Disertacijos rezultatų pagrindu buvo sukurtas... [toliau žr. visą tekstą] / The main goal of this dissertation was to assess prospectively the value of two cardiovascular magnetic resonance methodises (the transmural extent of an late gadolinium enhancement and the contractile reserve during low dose dobutamine administration) as predictors of left ventricular segmental and global functional recovery in patients with left ventricular systolic dysfunction undergoing surgical or percutaneous revascularisation. Taking into account previous studies, revascularisation of the viable myocardium results in an improvement of patient’s symptoms and prognosis. This finding emphasized the need for and importance of noninvasive tests to quantify the amount of viable myocardium in patients with left ventricular dysfunction in order to define the optimal management strategy. On the basis of the research described in the dissertation, the diagnostic value of different cardiovascular magnetic resonance based viability prediction methods was assessed. The superiority of combined viability prediction model incorporating an late gadolinium enhancement and the contractile reserve during low dose dobutamine administration was confirmed. The optimal predictors of the significant improvement of left ventricular ejection fraction were found: the percentage of viable segments from all dysfunctional and revascularised segments in a patient and the absolute value of left ventricular ejection fraction measured during low dose dobutamine administration. On the basis of the... [to full text]

Nous avons identifié l’expression du récepteur des angiopoïétines, le récepteur Tie2, à la surface des neutrophiles humains. De plus, nous avons démontré qu’Ang1 et Ang2 induisent des activités pro-inflammatoires sur les neutrophiles, comme l’adhésion aux cellules endothéliales (CEs) et la synthèse du facteur d’activation plaquettaire (PAF). Puisque le PAF augmente la viabilité des neutrophiles et que les angiopoïétines modulent la survie des CEs, nous avons voulu évaluer l’effet des angiopoïétines sur la survie des neutrophiles. Des neutrophiles humains ont été isolés à partir du sang de donneurs sains en accord avec le comité d’éthique de l’Institut de cardiologie de Montréal. La viabilité des neutrophiles a été mesurée par cytométrie en flux à l’aide de marqueurs d’apoptose et de nécrose. Un traitement avec des témoins positifs, soit l’interleukine 8 (IL-8; 25 nM) ou le PAF (100 nM), a augmenté la survie basale des neutrophiles de 34 et 27%, respectivement. De plus, un traitement avec Ang1 (1 pM – 10 nM) a augmenté la survie des neutrophiles jusqu’à 35%, alors qu’Ang2 n’a eu aucun effet. La combinaison de l’IL-8 ou du PAF avec Ang1 (10 nM) a eu un effet additif sur la viabilité des neutrophiles et a augmenté la survie de 56 et 60%, respectivement. Un prétraitement avec des anticorps bloquants contre l’IL-8 a permis d’inhiber l’activité anti-apoptotique de l’IL-8 et d’Ang1 de 92 et 80%, respectivement. Ainsi, notre étude est la première à démontrer la capacité d’Ang1 à prolonger la viabilité des neutrophiles, qui est principalement causée par la relâche d’IL-8. / We reported the expression of angiopoietin receptor Tie2 on the surface of human neutrophils. In addition, we reported that Ang1 and Ang2 are both capable to promote pro-inflammatory activities in neutrophils, namely their adhesion onto endothelial cells (ECs) and platelet-activating factor (PAF) synthesis. PAF is known to promote pro-survival activity on neutrophils and since both angiopoietins can modulate ECs viability, we addressed whether Ang1 and/or Ang2 could modulate neutrophil viability. Human neutrophils were isolated from blood of healthy volunteers in accordance with the guidelines of the Montreal Heart Institute’s ethical committee. Neutrophil viability was assessed by flow cytometry using apoptotic and necrotic markers. Treatment with anti-apoptotic mediators such as interleukin 8 (IL-8; 25 nM) and PAF (100 nM) increased neutrophil basal viability by 34 and 27%, respectively. In addition, treatment with Ang1 (1 pM – 10 nM) increased neutrophil viability by up to 35%, while Ang2 had no effect. Combination of IL-8 or PAF with Ang1 (10 nM) provided an additive effect on neutrophil viability and further increased viability by 56 and 60%, respectively. Pretreatment of the neutrophils with blocking anti-IL-8 antibodies inhibited the anti-apoptotic effect of IL-8 and Ang1 by 92 and 80%, respectively. In summary, our data are the first one to report Ang1 pro-survival activity on neutrophils, which is mainly driven through IL-8 release.