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Age-Associated Changes In The Kinetics Of Ventilation And Pulmonary Gas Exchange, Mark Anthony Babcock
Age-Associated Changes In The Kinetics Of Ventilation And Pulmonary Gas Exchange, Mark Anthony Babcock
Digitized Theses
The purpose of these studies was to examine ageing effects on the dynamics of pulmonary gas exchange and ventilation during the transition from light to moderate work. In the first study maximal oxygen uptake (VO{dollar}\sb2{dollar}max), ventilation threshold (VeT), the time constant for VO{dollar}\sb2{dollar} ({dollar}\tau\sp\prime{dollar}VO{dollar}\sb2{dollar}), and efficiency were determined from a ramp forcing test in eighty-three males aged 30 to 84y. The results showed a decline in VO{dollar}\sb2{dollar}max with age of {dollar}-{dollar}0.037 1{dollar}\cdot{dollar}min{dollar}\sp{lcub}-1{rcub}{dollar} per year. The VeT also declined with age but at one-third the rate of loss of the VO{dollar}\sb2{dollar}max. The {dollar}\tau\sp\prime{dollar}VO{dollar}\sb2{dollar} increased with age; the older group (60+y) had …
Natural Lta Tumor Cell Resistance To Malignant Conversion By Oncogenesras Andmyc, Alan Bradley Tuck
Natural Lta Tumor Cell Resistance To Malignant Conversion By Oncogenesras Andmyc, Alan Bradley Tuck
Digitized Theses
A tumorigenic, non-metastatic murine fibroblast cell line (LTA) was here used to study aspects of natural cellular resistance to induction of progression to malignancy. The nature of LTA cell growth was established by testing both in vitro and in vivo. In vitro growth showed some but not all characteristic features of transformation (eg. cells showed little contact inhibition of cell growth and were able to multilayer, but were not serum independent). In vivo tumor growth was that of a benign (non-metastatic) fibrosarcoma. Attempts were made to induce LTA cell progression to malignancy by both epigenetic and genetic means. Treatment of …
A Genetic Analysis Of Folate Transport In Chinese Hamster Ovary Cells, T Michael Underhill
A Genetic Analysis Of Folate Transport In Chinese Hamster Ovary Cells, T Michael Underhill
Digitized Theses
Chinese Hamster Ovary cells that are about 50x more resistant to the cytotoxic action of methotrexate than wild-type cells were deficient in the ability to take up methotrexate. In the absence of any exogeneous folates these cells require 100-250x the level of folinic acid as do wild-type cells to support growth at a similar level. Two classes of mutants were distinguishable by their revertability for growth on folinic acid and ability to take-up folic acid. Revertants derived from one class were similar to wild-type cells in their ability to grow in medium containing low levels of folinic acid and in …
Determinants Of Critical Power And Anaerobic Work Capacity In Young And Elderly Men, Thomas James Overend
Determinants Of Critical Power And Anaerobic Work Capacity In Young And Elderly Men, Thomas James Overend
Digitized Theses
Determinants of critical power (CP, the theoretical maximal rate of non-fatiguing work) and anaerobic work capacity (AWC, a finite energetic reserve from intra-muscular sources) were determined in young (n = 13, 24.5 y) and elderly men (n = 12, 70.7 y). The purposes of the four studies were to: (1a) determine and compare CP and AWC in young and elderly men; (1b) determine if CP does represent a true maximal rate of non-fatiguing work; (2) determine thigh component cross-sectional areas (CSA) and volumes; (3) determine the strength and strength/CSA ratios of the knee extensors and knee flexors; and (4) identify …
The Structure, Biosynthesis And Function Of Corticosteroid Binding Globulin, Carolyn L. Smith
The Structure, Biosynthesis And Function Of Corticosteroid Binding Globulin, Carolyn L. Smith
Digitized Theses
Corticosteroid binding globulin (CBG) is the major plasma transport protein for glucocorticoids. Complementary DNAs for rat, mouse, rabbit and squirrel monkey CBG were isolated, sequenced and their deduced primary structures were aligned. Overall, they exhibit 40.9% identity, and their comparison revealed conserved N-glycosylation sites and the probable position of the cysteine located within the human CBG steroid binding domain. Rat CBG mRNA is produced primarily by the liver, and in adults, males have two-thirds the CBG mRNA levels of females. During the last third of pregnancy, maternal hepatic CBG mRNA levels are relatively constant while fetal levels are highest at …
The Theory Of Character-Based Community Analysis, Valerio De Pillar
The Theory Of Character-Based Community Analysis, Valerio De Pillar
Digitized Theses
Vegetation analysis is, as a rule, comparative. Based on community components, which are plant populations, the analysis is necessarily taxonomy dependent. The fact that alternative taxonomies may, depending on the defining character set and the degree of fuzziness inherent in grouping plant individuals, lead to different perceptions has been notoriously unobserved by the dominant ecological tradition.;In the presence of choice, the question arises: which taxonomy? My main theses in the dissertation are concerned with how to answer this question. Specifically, I argue that: (1) Different taxonomic systems have conceptual justification and practical utility in vegetation studies. (2) The utility of …
Mucus-Secreting Cells Of The Colon In Health And Disease, Deena Patricia Rodney
Mucus-Secreting Cells Of The Colon In Health And Disease, Deena Patricia Rodney
Digitized Theses
Two morphologically distinct mucous cell types have been described in the ascending colon of rat and man. These include the goblet cells and non-goblet mucous (NGM) cells. The latter are known in the rat as "deep crypt secretory" (DCS) cells.;The purpose of this study was to examine various aspects of these NGM cells, including the histochemical nature of the rat DCS cell and human NGM cells. In addition, the reactions of the NGM cells were studied and compared to those of the goblet cells in an experimental model of colitis and in human IBD. A range of mammalian species, classed …
Regulation Of Porcine Thecal Cell Steroidogenesis By Locally Produced Factors, Heidi E. Engelhardt
Regulation Of Porcine Thecal Cell Steroidogenesis By Locally Produced Factors, Heidi E. Engelhardt
Digitized Theses
Regulation of steroidogenesis (measured by radioimmunoassay) by peptides produced within the ovary was investigated in monolayer cultures of porcine thecal cells (TC). In serum-free cultures LH but not FSH stimulated accumulation of androstenedione (Ad) and progesterone (P). No further accumulation of either steroid occurred after 19h. Addition of fetal bovine serum (FBS; optimal at 1%) maintained steroidogenesis for 3-4 days, but Ad production declined, and, in the presence of LH, P production increased. IGF-I plus LH markedly enhanced P production, an effect most pronounced after 3-4 days of treatment, and not associated with increases in DNA per well. Changes in …
Statistical Inference For An Interacting Particle System, Willard J. Braun
Statistical Inference For An Interacting Particle System, Willard J. Braun
Digitized Theses
The growth patterns of cell tumors may be modelled stochastically by a multi-type lattice interacting particle system. The process is Markovian in time with spatial nearest-neighbor interactions. The cell population growth depends on several numerical parameters. These parameters specify the fission rates for individual cells and the types of resulting offspring cells.;Experimental methodology allows such a process to be observed at a specific time. It is assumed that the data obtained at this time is in the form of counts of cells of different types and locations. Based on such data, it is shown that certain statistics such as cell …
The Role Of Genetic And Phenotypic Variation In The Colonization Biology Of The Weedy Nightshade, Solanum Ptycanthum Dun, Luise Anne Hermanutz
The Role Of Genetic And Phenotypic Variation In The Colonization Biology Of The Weedy Nightshade, Solanum Ptycanthum Dun, Luise Anne Hermanutz
Digitized Theses
Solanum ptycanthum (eastern black nightshade) is a serious weed of tomato and soybean crops at the northern margin of its distribution in southwestern Ontario. Evidence for direct immigration, albeit at low, sporadic frequencies, of nightshade into these agrestal habitats occurs via tomato transplants imported from Georgia and North Carolina. Northern ruderal populations are also common in a variety of natural habitats. Outcrossing rates in northern and southern genotypes were compared in simulated populations grown in northern agricultural habitats. Greenhouse experiments were used to examine levels of genetic variation and phenotypic plasticity in life history traits among ruderal, agrestal and southern …
Studies On The Compositional And Metabolic Heterogeneity Of Very Low-Density Lipoproteins In Hypertriglyceridemic Human Subjects, Andrew John Evans
Studies On The Compositional And Metabolic Heterogeneity Of Very Low-Density Lipoproteins In Hypertriglyceridemic Human Subjects, Andrew John Evans
Digitized Theses
Experiments were designed to characterize more fully specific aspects of the compositional and metabolic heterogeneity of Sf 60-400 very low density lipoproteins (VLDL) known to be associated with Type IV hypertriglyceridemia in humans. Apolipoprotein E (apo E) is thought to be an important mediator of VLDL catabolism. Heparin-Sepharose chromatography was shown to be a reproducible method for separating Type IV VLDL into apo E-poor and apo E-rich subfractions. The apo E-poor fraction was found to contain more intestinally-derived lipoproteins than the apo E-rich fraction. VLDL from subjects with Types I, III and V hyperlipoproteinemia could not be subfractionated in an …