Browsing by Author "Ward, Ewan"
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Item Item Digestion of Repair Sites in Rat Liver DNA by Endogenous Nucleases(1986-11-01) Haber, Michelle; Stewart, Bernard W.; Ward, EwanThe proportion of sheared rat liver DNA recovered from benzoylated DEAE-cellulose in the final stage following stepwise elution with NaCl and caffeine solutions was dependent upon the DNA isolation procedure. An increase in the proportion of DNA containing single stranded regions, consequent upon delay or addition of Mg2+ prior to phenol extraction, suggested nuclease mediated degradation. Administration of methyl methanesulphonate to rats resulted in a consistent proportional increase in the caffeine-eluted fraction. The results of caffeine gradient elution of control and alkylated DNA from benzoylated DEAE-cellulose were consistent with repair-associated single stranded regions being substrates for endogenous single strand-specific exonucleases.
Item HDL Subfraction Changes with a Low-fat, Plant-based Complete Health Improvement Program (CHIP)(2018-09-01) Ward, Ewan; Rankin, Paul; Morton, Darren; Watts, Greg; Grant, Ross; Kent, LillianBackground and Objectives: Low HDL concentrations are considered an important risk factor for cardiovascular disease. Interventions promoting a low-fat, plant-based eating pattern appear to reduce CVD risk while paradoxically also reducing HDL concentrations. Recent studies show HDL to comprise a range of subfractions, but the role these play in ameliorating the risk of CVD is unclear. The purpose of this study was to characterise changes in HDL subfractions in participants where HDL decreased following the CHIP intervention which promotes a low-fat, plant-based diet, with physical activity. Methods and Study Design: Individuals (n=22; mean age=55.4±16.3 years; 45.5% men, 54.5% women) participating in a CHIP intervention were assessed at baseline and 30 days for changes in BMI, blood pressure, lipid profile, (including large-, intermediate- and small-HDL subfractions) and fasting glucose. Results: HDL significantly decreased (10.6%, pConclusions: This paper discusses specific changes in HDL subfractions when overall-HDL decreases as a response to low fat, whole-food, plant-based eating and exercise. Additional research is required to elucidate the reasons through which behavioural therapies remodel the HDL particle and how this impacts the functional properties of HDL and CVD risk.
Item Intelligent Design: The Biochemical Challenge to Darwinian Evolution?(2001-01-01) Hancock, Marty A.; Ward, EwanThe idea that nature shows evidence of intelligent design has been argued by theologians and scientists for centuries. The most famous of the design arguments is Paley’s watchmaker illustration from his writings of the early 19th century. Interest in the concept of design in nature has recently had a resurgence and is often termed the Intelligent Design movement. Significant is the work of Michael Behe on biochemical systems. In his book, Darwin’s Black Box, Behe develops the idea that many biochemical systems are irreducibly complex in the sense that each component of these systems is essential for their functioning and cannot be removed or altered without compromising the system of which they are a part. Thus traditional Darwinian evolutionary theory has difficulty in explaining their development. When applied to the question of life’s origin on this planet, design arguments raise serious questions about traditional views of chemical evolution. To be considered a scientific alternative to Darwinian evolution, intelligent design needs to be empirically detectable. The development of a three-stage explanatory filter by William Dembski is arguably a fully scientific method that can, on the basis of observational data, reliably distinguish intelligent design in biological systems from undirected natural causes. However, at this stage, detection of intelligent design does not necessitate speculation on the nature of the designer, but does infer an intelligence behind the design.
Item Long Term Persistence of Nitrosamine-Induced Structural Damage to Heterochromatic DNA(1987-01-01) Ward, Ewan; Stewart, Bernard W.Different levels of damage and repair to eu- and heterochromatic DNA from the livers of rats receiving a dose of 10 mg/kg N-nitrosodimethylamine (NDMA) were apparent. Preincorporated 3H~thymidine was lost rapidly from euchromatic DNA but persisted in the heterochromatic fraction. Persistent damage, determined as single-stranded regions binding 10 benzoylated DEAE-cellulose (BD-cellulose), was evident in heterochromatic DNA for up to three months. By subjecting rats treated with NDMA to partial hepatectomy, generation of single-stranded regions in the newly synthesized heterochromatic DNA could be demonstrated. Such structural defects were evident when hepatectomy was performed two months after administration of the carcinogen. These findings indicate that structural damage to non-transcribed DNA is one of the most persistent molecular lesions following exposure to nitrosamines.
Item Persistent and Heritable Structural Damage Induced in Heterochromatic DNA from Rat Liver by N-Nitrosodimethylamine(1987-03-01) Stewart, Bernard W.; Ward, EwanAnalysis, by benzoylated DEAE-cellulose chromatography, has been made of structural change in eu- and heterochromatic DNA from rat liver following administration of the carcinogen N-nitrosodimethylamine. Either hepatic DNA was prelabeled with [3H]thymidine administered 2-3 weeks before injection of the carcinogen or the labeled precursor was given during regenerative hyperplasia in rats treated earlier with N-nitrosodimethylamine. Following phenol extraction of either whole liver homogenate or nuclease-fractionated eu- and heterochromatin, carcinogen-modified DNA was examined by stepwise or caffeine gradient elution from benzoylated DEAE-cellulose. In whole DNA, nitrosamine-induced single-stranded character was maximal 4-24 h after treatment, declining rapidly thereafter; gradient elution of these DNA preparations also provided short-term evidence of structural change. Caffeine gradient chromatography suggested short-term nitrosamine-induced structural change in euchromatic DNA, while increased binding of heterochromatic DNA was evident for up to 3 months after carcinogen treatment. Preparations of newly synthesized heterochromatic DNA from animals subjected to hepatectomy up to 2 months after carcinogen treatment provided evidence of heritable structural damage. Carcinogen-induced binding of heterochromatic DNA to benzoylated DEAE-cellulose was indicative of specific structural lesions whose affinity equalled that of single-stranded DNA up to 1.0 kilobase of single-stranded DNA up to 1.0 kilobase in length. The data suggest that structural lesions in heterochromatin, which may be a consequence of incomplete repair, are preferentially degraded by endogenous nuclease(s)
Item Potential Small and Large-Scale Effects of Mechanical Beach Cleaning on Biological Assemblages of Exposed Sandy Beaches Receiving Low Inputs of Beach-Cast Macroalgae(2015-11-01) de Berg, Kevin C.; Ward, Ewan; Morton, Jason K.Mechanical beach cleaning occurs worldwide on heavily urbanised beaches to remove litter and decomposing macroalgae from impacting tourismand recreation. This study investigated the potential small- (100 s of metres) and largescale (kms) ecological impacts of beach cleaning in a region receiving low inputs of macroalgae with a focus on: levels of total nitrogen and nitrate; abundances of bacteria, meiofauna, macrofauna and ocypodid crabs; and assemblages of meiofauna and macrofauna. Results indicated that beach cleaning was not having an impact. Given beach cleaning occurred only weekly to twice-weekly on small sections of a few beaches, and that collected beach-cast macroalgae in the study region is relocated on the same beach for degradation, it is likely that nutrients are redistributed from surrounding areas to cleaned sites and that potential physical impacts to biota are short-term and sustainable. Impacts of beach cleaning may be evident in regions that experience more extensive beach cleaning operations or on beaches with high inputs of beachcast macroalgae. This study also highlights the importance of comparing sites at the same location to investigate the effects of beach cleaning, as ecological differences among distant locations may incorrectly be attributed to beach cleaning but may actually be driven by differences in their physical characteristics.
Item Science for Primary Teachers(2014-01-01) Ward, Ewan; Morton, Jason K.; Boddey, Kerrie; Christian, Gemma J.; Rogers, LyndenThe general aim of this textbook was to provide some basic knowledge of how science works. After all, we live in a very science-oriented and techno world. We also wanted to make it easier for you to get your pupils interested in science.
Item Single-strand Specific Degradation of DNA During Isolation of Rat Liver Nuclei(1985-10-01) Stewart, Bernard W.; Norris, Murray D.; Haber, Michelle; Ward, EwanWe have investigated structural change in rat liver DNA produced by different isolation procedures and specifically compared the integrity of DNA derived by phenol extraction from isolated and purified nuclei with preparations extracted immediately from a crude liver homogenate containing intact nuclei. As indicated by stepwise elution from benzoylated DEAE-cellulose, most structural change in DNA was evident following nuclei isolation. Damage principally involved generation of single-stranded regions in otherwise double-stranded DNA fragments; totally single-stranded DNA was not detected by hydroxylapatite chromatography. Caffeine gradient elution suggested formation of single-stranded regions extending for up to several kilobases. In neutral sucrose gradients, differences in sedimentation rates of respective DNA samples consequent upon S1 nuclease digestion could be detected after isolation of nuclei, though not in other circumstances. The observed single-strand-specific nuclease digestion of DNA could apparently be reduced if steps were taken to reduce autodigestion during nuclei isolation by reduction of temperature and covalent cation concentration. The results are discussed in terms of the use of exogenous and endogenous nucleases in chromatin fractionation studies involving isolated nuclei and possible artifactual findings that may be generated by single-strand-specific autodigestion.
Item The Biochemical and Pathophysiological Effects of Alcohol Consumption(2010-07-01) Ward, Ewan; Sheedy, Daniel; Lassila, Sophie; Kemp, Amanda; Beecroft, JodieWhile the stance of some conservative Christian (and other) groups advocating abstinence from alcohol intake may not be popular, contemporary research into alcohol and its effects on the body may lend weight to such a position. The consumption of alcohol, coupled with its addictive properties, can lead to a wide not only costly in medical terms but also in terms of domestic violence, accidents and antisocial behaviour.
Alcohol is metabolised by the liver and this organ may be consequently damaged resulting in serious impairment of normal hepatic structure and function. Nearly all the physiological systems of the body are adversely affected by alcohol to varying degrees and the behavioural effects observed with intoxication are associated with compromised neurotransmitter functions in the brain and altered brain structure in the long term. Adverse consequences of alcohol intake may be evident in other systems including the cardiovascular, gastrointestinal, reproductive and immunological systems. There is an increased risk of atherosclerosis, cancers of the oral cavity, pancreatitis and immune system disturbances associated with prolonged alcohol intake. In pregnant women alcohol metabolism is reduced and as the developing foetus has lowered ability to metabolise blood alcohol compared to an adult there is an elevated risk of serious consequences associated with foetal alcohol syndrome. Despite the nearly overwhelming negative consequences of alcohol intake, the beneficial effects of drinking red wine linked to lowered heart disease despite a high fat diet (the ‘French Paradox’) may be associated with the antioxidants and other polyphenols also found in non-alcoholic red grape juice. Serious consideration of the effects of alcohol on the body should inform decisions on the intake of alcohol.
Item The Effect of a Low-Fat, Plant-Based Lifestyle Intervention (CHIP) on Serum HDL Levels and the Implications for Metabolic Syndrome Status - A Cohort Study(2013-10-01) Diehl, Hans A.; Gobble, John; Grant, Ross; Ward, Ewan; Rankin, Paul; Morton, Darren; Kent, LillianBackground
Low levels of high-density lipoproteins (HDL) are considered an important risk factor for cardiovascular disease and constitute one of the criteria for the Metabolic Syndrome (MetS). Lifestyle interventions promoting a low-fat, plant-based eating pattern appear to paradoxically reduce cardiovascular risk but also HDL levels. This study examined the changes in MetS risk factors, in particular HDL, in a large cohort participating in a 30-day lifestyle intervention that promoted a low-fat, plant-based eating pattern.
Methods
Individuals (n = 5,046; mean age = 57.3 ± 12.9 years; 33.5% men, 66.5% women) participating in a in a Complete Health Improvement Program (CHIP) lifestyle intervention within the United States were assessed at baseline and 30 days for changes in body mass index (BMI), blood pressure (BP), lipid profile and fasting plasma glucose (FPG).
Results
HDL levels decreased by 8.7% (p
Conclusions
When people move towards a low-fat, plant-based diet, HDL levels decrease while other indicators of cardiovascular risk improve. This observation raises questions regarding the value of using HDL levels as a predictor of cardiovascular risk in populations who do not consume a typical western diet. As HDL is part of the assemblage of risk factors that constitute MetS, classifying individuals with MetS may not be appropriate in clinical practice or research when applying lifestyle interventions that promote a plant-based eating pattern.[from publisher's website].
Item The Effect of a Low-Fat, Plant-Based Lifestyle Intervention (CHIP) on Serum HDL Subfraction Levels - A Cohort Study(2017-06-01) Ward, Ewan; Morton, Darren; Watts, Greg; Grant, Ross; Kent, LillianThis conference abstract discusses a low-fat plant-based diet and the effect it has on HDL levels
Item The Influence of Religious Affiliation on Participant Responsiveness to the Complete Health Improvement Program (CHIP) Lifestyle Intervention(2016-10-01) Diehl, Hans A.; Gobble, John; Ferret, Rick; Rankin, Paul; Ward, Ewan; Morton, Darren; Kent, LillianSeventh-day Adventist (SDA) and non-SDA (21.3 and 78.7 %, respectively) individuals (n = 7172) participating in the Complete Health Improvement Program, a 30-day diet and lifestyle intervention, in North America (241 programs, 2006–2012) were assessed for changes in selected chronic disease risk factors: body mass index (BMI), blood pressure (BP), pulse, lipid profile and fasting plasma glucose (FPG). Reductions were greater among the non-SDA for BMI, pulse and blood lipids. Furthermore, the majority of non-SDA in the highest risk classifications for BP, lipids and FPG, but only some lipids among SDA, were able to show improvement by 20 % or more.
Publication The Mechanics of Intelligent Design — Good Enough to Teach?(Avondale Academic Press, 2008-01-01) Ward, EwanConsiderable debate has taken place in the last two years over whether or not Intelligent Design (ID) should be taught to high school students. This paper examines some of the basic features of ID as set out by its major proponents. It also outlines the arguments of detractors who would argue that ID is not science, but religion or creationism in disguise. These suggest that ID is a type of ‘god of the gaps’ argument which then languishes when mechanisms accounting for the appearance of complex objects or systems having the hallmarks of design are elucidated by further scientific research. It is also noted that while the complexity, functionality and apparent purpose of biological systems may have the appearance of being designed, other explanations exist. Further, it is noted that design theory is unable to speculate on the mechanism(s) leading to their formation. It is also observed that the design discussion has some general concepts which go beyond the specific ID framework and with which many more Christians in science resonate. Internationally, ID has not featured in school science curricula and attempts to integrate it into Australian school curricula should be very carefully evaluated with respect to the experiences of the global educational and scientific community.