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The Distribution, Exposure Dynamics And Toxic Significance Of 42 Polychlorinated Biphenyls (Including Three Coplanar Congeners), In Biota And Sediment From The Western Basin Of Lake Erie., Susan Elizabeth. Koslowski
The Distribution, Exposure Dynamics And Toxic Significance Of 42 Polychlorinated Biphenyls (Including Three Coplanar Congeners), In Biota And Sediment From The Western Basin Of Lake Erie., Susan Elizabeth. Koslowski
Electronic Theses and Dissertations
Polyclorinated biphenyls are ubiquitous pollutants which are associated with wasting syndrome, reproductive problems, teratogenicity and mortality in wildlife (Borgmann et al. 1990; Kubiak et al. 1989). There are 209 PCB congeners which differentially partition, bioaccumulate and degrade in the environment. It is important to analyze the exposure dynamics of individual PCBs, as congener toxicity and persistence varies considerably. This study examined the dynamics and distribution of 42 congeners in sediment and biota from the Western Basin of Lake Erie. The non-ortho substituted congeners IUPAC #77, #126 and #169 were quantified, and their concentrations were examined in various trophic levels. The …
Life History Characteristics And Size Variation Of The Burrowing Mayfly Hexagenia (Ephemeroptera: Ephemeridae): Maternal Vs. Environmental Constraints., Elizabeth Christene. Hanes
Life History Characteristics And Size Variation Of The Burrowing Mayfly Hexagenia (Ephemeroptera: Ephemeridae): Maternal Vs. Environmental Constraints., Elizabeth Christene. Hanes
Electronic Theses and Dissertations
There is tremendous size variation within both laboratory and field populations of the mayfly Hexagenia. I studied the size variation in adults (imagoes) of this mayfly collected in the summers of 1989 and 1990 from Lake St. Clair, Southwestern Ontario (42$\sp\circ$20$\sp\prime$N; 82$\sp\circ57\sp\prime$W). Additionally, I examined the influence of endogenous factors (egg hatching, egg diapause, maternal size) on size and survivorship of larval Hexagenia. Female imagoes collected early in the emergence period were significantly larger than females collected later in the summer. There was low incidence of parthenogenesis ($<$5%), egg diapause ($<$0.01%) and viability of eggs produced through interspecific mating (0%) in the laboratory. Egg size of H. limbata was negatively correlated with collection date. Although egg size did vary among female sizes, there was no clear relationship between egg size and maternal size. Maternal size was negatively correlated with larval size, after 40 d growth. Maternal size and (maternal size$\sp2$) were correlated with per cent larval survival. Maternal parents exhibiting mean body length produced larvae with the highest survivorship after 40 d growth. The length of incubation (days) required for egg hatch was negatively associated with per cent larval survival (40 d) but was positively correlated with larval size (80 d). Of sediments examined from six different waterbodies, Saginaw Bay sediment provided larvae with the best survivorship and the largest size, and when given a choice, larvae selected that sediment type. Subsequently, I developed a standard sediment (STND-3) that mimiced the particle size distribution and organic content of Saginaw Bay sediment. (Abstract shortened by UMI.)Dept. of Biological Sciences. Paper copy at Leddy Library: Theses & Major Papers - Basement, West Bldg. / Call Number: Thesis1993 .H354. Source: Masters Abstracts International, Volume: 32-02, page: 0540. Adviser: J. J. H. Ciborowski. Thesis (M.Sc.)--University of Windsor (Canada), 1993.
Studies In Excitation-Contraction Coupling In Isoproterenol-Induced Hypertrophied Rat Heart., Lihui. Tang
Studies In Excitation-Contraction Coupling In Isoproterenol-Induced Hypertrophied Rat Heart., Lihui. Tang
Electronic Theses and Dissertations
Cardiac hypertrophy was induced by daily subcutaneous injections of isoproterenol (0.3 mg/kg. body weight) for 12 consecutive days. A significant increase in whole ventricular weight (35.7%) was achieved. Regionally, the right ventricle produced a greater hypertrophy response than the left ventricle. Contractile force, +Dt/dt, and $-$DT/dt in right ventricular trabecular muscle were significantly increased, suggesting that either Ca$\sp{2+}$ responsiveness of the myofilaments or the availability of (Ca$\sp{2+}\rbrack\rm\sb i$ was increased. The Ca$\sp{2+}$ sensitivity of the myofilaments was investigated using a Triton-100 skinned trabecular preparation. The force-pCa relationship showed no difference in the myofilament Ca$\sp{2+}$ sensitivity. The force-interval relationship was studied …
Expression Of Lysosomal Cysteine Protease Activities In Differentiating Hepatocyte And Myoblast Cells In Culture., Derek Thomas. Jane
Expression Of Lysosomal Cysteine Protease Activities In Differentiating Hepatocyte And Myoblast Cells In Culture., Derek Thomas. Jane
Electronic Theses and Dissertations
The expression of the lysosomal cysteine proteases, cathepsins B, H and L and cysteine protease inhibitors in intracellular and extracellular fractions prepared from the differentiating malignantly transformed human hepatoma cell line HepG2, the differentiating rat myoblast cell line L6, and the L6-D3 non-fusing variant, were examined using synthetic substrates. HepG2 cells were established in serum-free medium for greater than 100 generations and demonstrated biological (e.g., growth characteristics) and biochemical (e.g., the synthesis and secretion of apolipoprotein B and cathepsin B) parameters similar to their serum-grown counterparts. HepG2 cells expressed high constant levels of intracellular cathepsins B and L activity as …
The Olfactory Organ Of Sea Lamprey, Petromyzon Marinus L. During Metamorphosis: Morphological Changes And Morphometric Analysis., Jamie. Vandenbossche
The Olfactory Organ Of Sea Lamprey, Petromyzon Marinus L. During Metamorphosis: Morphological Changes And Morphometric Analysis., Jamie. Vandenbossche
Electronic Theses and Dissertations
Metamorphosis of the primitive Agnathan vertebrates, the sea lampreys, Petromyzon marinus L., is a programmed and highly synchronized sequence of changes in external and internal structures. Before metamorphosis, the olfactory organ is relatively small and contains thin densely packed cells, whereas after metamorphosis, it is large, and contains lamellar folds with wider more distinct olfactory epithelial cells (VanDenbossche et al., '93). We have used scanning electron microscopy and right microscopy of 1 $\mu$m sections of epoxy embedded tissue to document changes in the structure of the olfactory sac during the seven stages of metamorphosis (M1-M7). The changes I observed in …
An Investigation Of Frequency And Length Changes In Diabetic Papillary Muscles., Patrick Neil Alexander
An Investigation Of Frequency And Length Changes In Diabetic Papillary Muscles., Patrick Neil Alexander
Electronic Theses and Dissertations
The length-dependence of several excitation-contraction coupling elements were investigated in diabetic papillary muscles. Female Wistar rats (200-300 g) were chemically-induced with a single tail vein injection of streptozotocin (65 mg/kg) and sacrificed a minimum of 5 weeks later. Twitch curves at 100 and 95%L$\sb{\rm max}$ (percentage of optimal length) of diabetic myocardium, compared to the control group, demonstrated significant, p $<$ 0.05, depressions in the maximal rates of contraction and relaxation, and prolongation of the time to peak contraction, the time to maximal relaxation, time to the maximal rate of contraction and relaxation. The reduction of muscle length caused similar significant, p $<$ 0.05, depressions of these parameters including peak muscle force, in both the control and diabetic groups, although in the diabetic group there was no significant change in the maximal rate of relaxation. Force-interval data revealed that diabetes caused significant depressions, p $<$ 0.05, of both the beta and gamma phases at 100 and 95%L$\sb{\rm max}$ The reduction of muscle length caused significantly greater, p $<$ 0.05, potentiation during the beta and gamma phases at 95%L$\sb{\rm max}$ in the control group, however, there were no significant differences observed in the diabetic group. The addition of ryanodine (1 $\mu$M) coupled with increases in frequency, 1.67, 2.50, 3.33 and 5.00 Hz, was used to investigate whether diabetes caused an alteration of the calcium influx through the slow calcium channel. Both the control and diabetic groups exhibited negative inotropic effects, and upon an increase in stimulation from a pacing frequency of 0.5 Hz, produced positive staircases. Comparison was accomplished by assessing the number of beats required to attain relative percentages of the staircase force. There were no significant differences, p $<$ 0.05, at 100 and 95%L$\sb{\rm max}$ between the control and diabetic groups although it seemed that fewer beats were required for the diabetic group to achieve relative percentages of staircase force. Upon a reduction in muscle length, both the control and diabetic groups exhibited, in almost every comparison, no significant differences, p $<$ 0.05, in the number of beats required to reach a relative percentage of staircase force.Dept. of Kinesiology. Paper copy at Leddy Library: Theses & Major Papers - Basement, West Bldg. / Call Number: Thesis1993 .A576. Source: Masters Abstracts International, Volume: 32-06, page: 1598. Adviser: Kenji Kenno. Thesis (M.H.K.)--University of Windsor (Canada), 1993.
Studies Of Trehalose Metabolism In Dictyostelium Discoideum: The Role Of Trehalose In Stress Management And The Purification Of Trehalase., Lesly Ann. Temesvari
Studies Of Trehalose Metabolism In Dictyostelium Discoideum: The Role Of Trehalose In Stress Management And The Purification Of Trehalase., Lesly Ann. Temesvari
Electronic Theses and Dissertations
The levels of the disaccharide trehalose, in the dormant stages of various slime molds, were determined. Trehalose comprised 7.1%, 2.4%, 3.2%, and 3.4% of the dry weight of Dictyostelium mucoroides macrocysts, Polysphondylium pallidum microcysts, and Dictyostelium discoideum spores (strains AC4 and SG1), respectively. In the vegetative amoebae of D. discoideum, and P. pallidum, additional roles for this storage carbohydrate were examined. It was found that trehalose could also act as a general stress manager; its levels increasing to those observed in dormant structures, when amoebae were exposed to heat (30$\sp\circ$C), cold (4$\sp\circ$C) and heavy metals. Trehalose-6-phosphate synthetase and trehalase activities …
Characterization Of Cysteine Protease And Cysteine Protease Inhibitor Activities In Mcf-7, And Mcf-7/Adr(R) Human Breast Cancer Cells., Paul Blakely. Scaddan
Characterization Of Cysteine Protease And Cysteine Protease Inhibitor Activities In Mcf-7, And Mcf-7/Adr(R) Human Breast Cancer Cells., Paul Blakely. Scaddan
Electronic Theses and Dissertations
The expression of the lysosomal cysteine proteases, cathepsins B, H, and L, and cysteine protease inhibitors in intracellular (cells) and extracellular (media) fractions prepared from the MCF-7 human breast cancer cell line, its adriamycin resistant variant, MCF-7/Adr$\sp{\rm R}$, and their somatic cell hybrid, M:A, was examined using synthetic substrates. Although these three cell populations had similar growth parameters, MCF-7/Adr$\sp{\rm R}$ demonstrated statistically significant 10-25 fold and 10-15 fold higher levels of intracellular cathepsins B and L activities respectively, than those found in the MCF-7 parent, or the M:A hybrid. Moreover, the increased levels of cathepsins B and L observed in …