Andrews University

Berrien Springs, MI, United States

Publications

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    ABSTRACT: Microsporidia are obligate intracellular parasites with extremely reduced genomes and a dependence on host-derived ATP. The microsporidium Encephalitozoon cuniculi proliferates within a membranous vacuole and we investigated how the ATP supply is optimized at the vacuole-host interface. Using spatial EM quantitation (stereology), we found a single layer of mitochondria coating substantial proportions of the parasitophorous vacuole. Mitochondrial binding occurred preferentially over the vegetative "meront" stages of the parasite, which bulged into the cytoplasm, thereby increasing the membrane surface available for mitochondrial interaction. In a broken cell system mitochondrial binding was maintained and was typified by electron dense structures (>10nm long) bridging between outer mitochondrial and vacuole membranes. In broken cells mitochondrial binding was sensitive to a range of protease treatments. The function of directly bound mitochondria, as measured by the membrane potential sensitive dye JC-1, was indistinguishable from other mitochondria in the cell although there was a generalized depression of the membrane potential in infected cells. Finally, quantitative immuno-EM revealed that the ATP-delivering mitochondrial porin, VDAC, was concentrated at the mitochondria-vacuole interaction site. Thus E. cuniculi appears to maximize ATP supply by direct binding of mitochondria to the parasitophorous vacuole bringing this organelle within 0.020 microns of the growing vegetative form of the parasite. ATP-delivery is further enhanced by clustering of ATP transporting porins in those regions of the outer mitochondrial membrane lying closest to the parasite.
    Cellular Microbiology 11/2013;
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    ABSTRACT: There is inconclusive evidence for the effectiveness of cryotherapy for the treatment of exercised induced muscle damage (EIMD). Small sample sizes and treatment applications that did not correspond to evidence based practice are limitations in previous studies that may have contributed to these equivocal findings. The purpose of this study was to examine the effectiveness of daily multiple applications of ice on EIMD throughout the 72-hour recovery period, an icing protocol that more closely resembles current clinical practice. Thirty-three subjects were assigned to either the cryotherapy group (n=23) or control group (n=10). EIMD was induced through repeated isokinetic eccentric contractions of the right hamstring muscle group. The experimental group received ice immediately after induction of EIMD and continued to ice 3x/day for 20-minutes throughout the 72 hours; the control group received no intervention. Isometric torque, hamstring length, pain, and biochemical markers (CK, ALT, and AST) were assessed at baseline, 24, 48, and 72 hours. Both groups demonstrated a significant change (p < .05) in all dependent variables compared to baseline, but there was no difference between groups except for pain. The cryotherapy group had significantly (p= .048) less pain (3.0 cm ± 2.1) compared to the control (5.35 cm ± 2.5) at 48 hours. Although not statistically significant, the cryotherapy group had greater range of motion and lower CK and AST means at 72 hours compared to the control group. Repeated applications of ice can decrease the pain associated with EIMD significantly at 48 hours post EIMD. While the results may not be unique, the methodology in this study was distinctive in that we used a larger sample size and an icing protocol similar to current recommended treatment practice.
    The Journal of Strength and Conditioning Research 01/2013;
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    ABSTRACT: College students are one of the most at-risk population groups for food poisoning, due to risky food safety behaviors. Using the Likert Scale, undergraduate students were asked to participate in a Food Safety Survey which was completed by 499 students ages 18-25. Data was analyzed using SPSS and AMOS statistical software. Four conceptual definitions regarding food safety were defined as: general food safety, bacterial food safety, produce food safety, and politics associated with food safety. Knowledge seems to be an important factor in shaping students attitudes regarding general and bacterial safety. Ethnicity plays a role in how people view the politics of food safety, and the safety of organic foods.
    Nutrients 01/2013; 5(2):328-39.
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    ABSTRACT: Exosomes are secreted by many cell types and display multiple biological functions. The ability to both rapidly detect and quantify exosomes in biological samples would assist in the screening of agents that interfere with their release, and which may therefore be of clinical relevance. Nanoparticle tracking analysis, which detects the size and concentration of exosomes, was used to monitor the inhibition of exosome secretion from MDA-MB-231 breast cancer cells expressing inhibitory RNA targeted for Rab27a, a known component of the exosome pathway. Inhibition of both Rab27a and Rab27b was observed, resulting in alterations to intracellular CD63+ compartments and the release of fewer exosomes into the culture medium, as determined by nanoparticle tracking analysis and confirmed by immunoblotting and protein quantification. These data show that nanoparticle tracking analysis can be used effectively and rapidly to monitor the disruption of exosome secretion.
    Experimental Cell Research 10/2012;
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    ABSTRACT: The crystal-field and Zeeman splittings of the energy levels of Nd3+(4f3) 2S+1LJ in hexagonal phase AlN have been investigated. The multiplet manifolds of Nd3+(4f3) analyzed include the ground state, 4I9/2, and excited states 4I11/2, 4I13/2, 4F3/2, 4F5/2, 2H(2)9/2, 4F7/2, 4S3/2, 4G5/2, and 2G7/2. Experimental energy levels were obtained from analyses of the 12 K cathodoluminescence spectra from Nd3+-implanted films of AlN, and from the 15 K photoluminescence excitation spectra and the site-selective combined excitation-emission spectra (CEES) recently reported for in situ Nd-doped hexagonal AlN grown by plasma-assisted molecular beam epitaxy (PA-MBE). CEES results identify a main site and two minority sites for Nd3+ in both samples. Transition line strengths attributed to the ion in minority sites are relatively stronger in Nd:AlN than in Nd:GaN. The 15 K experimental Zeeman splitting of Nd3+ are analyzed in the PA-MBE grown AlN samples and compared with the Zeeman splitting observed in Nd:GaN. The crystal-field and Zeeman splittings were modeled using a parametrized Hamiltonian consisting of atomic and crystal-field terms. We considered possible site distortion due to the size of the implanted Nd ion that would reduce the site symmetry from C3v to C3 or C1h. However, no significant improvement was obtained using these lower symmetry models, leading us to conclude that C3v symmetry is a reasonable approximation for the main site Nd3+ ions in AlN.
    Optical Materials Express 09/2012; 2(9):1176-1185.
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    ABSTRACT: In humans, coping behaviour is an action taken to soothe oneself during or after a stressful or threatening situation. Some human behaviours with physiological functions also serve as coping behaviours, for example, comfort sucking in infants and comfort eating in adults. In birds, the behaviour of preening, which has important physiological functions, has been postulated to soothe individuals after stressful situations. We combine two existing modelling approaches - logistic regression and Darwinian dynamics - to explore theoretically how a behaviour with crucial physiological function might evolve into a coping behaviour. We apply the method to preening in colonial seabirds to investigate whether and how preening might be co-opted as a coping behaviour in the presence of predators. We conduct an in-depth study of the environmental correlates of preening in a large gull colony in Washington, USA, and we perform an independent field test for comfort preening by computing the change in frequency of preening in gulls that were alerted to a predator, but did not flee.
    Journal of Biological Dynamics 01/2012; 6(1):17-37.
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    ABSTRACT: The Institute of Medicine noted that effective substance abuse treatment (SAT) programs integrate individual therapeutic approaches with transitional/ancillary services. In addition, research suggests that type of ownership impacts SAT services offered and that Medicaid plays a key role in SAT access. Data from the National Survey of Substance Abuse Treatment Services for the years 2000 and 2002-2006 were used to examine relationships among SAT program Medicaid acceptance, program ownership, and transitional/ancillary service accessibility. Multivariate logistic regression models controlling for state- and program-level contextual factors were used to analyze the data. Nonprofit SAT programs were significantly more likely to offer transitional/ancillary services than for-profit programs. However, programs that accepted Medicaid, regardless of ownership, were significantly more likely to offer most transitional/ancillary services. The data suggest that Medicaid may play a significant role in offering key transitional/ancillary services related to successful treatment outcome, regardless of program ownership type.
    Journal of substance abuse treatment 12/2011; 42(2):116-24.
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    ABSTRACT: Walnuts contain a number of potentially neuroprotective compounds like vitamin E, folate, melatonin, several antioxidative polyphenols and significant amounts of n-3 α-linolenic fatty acid. The present study sought to determine the effect of walnuts on verbal and non-verbal reasoning, memory and mood. A total of sixty-four college students were randomly assigned to two treatment sequences in a crossover fashion: walnuts-placebo or placebo-walnuts. Baseline data were collected for non-verbal reasoning, verbal reasoning, memory and mood states. Data were collected again after 8 weeks of intervention. After 6 weeks of washout, the intervention groups followed the diets in reverse order. Data were collected once more at the end of the 8-week intervention period. No significant increases were detected for mood, non-verbal reasoning or memory on the walnut-supplemented diet. However, inferential verbal reasoning increased significantly by 11·2 %, indicating a medium effect size (P = 0·009; d = 0·567). In young, healthy, normal adults, walnuts do not appear to improve memory, mood or non-verbal reasoning abilities. However, walnuts may have the ability to increase inferential reasoning.
    The British journal of nutrition 09/2011;
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    ABSTRACT: Drug resistance is a major hurdle in the global battle against tuberculosis (TB). In tackling this problem it is important to understand both how resistance emerges as well as the ways in which multi-drug and extensively drug-resistant TB (M/XDR-TB) may be successfully treated. The biggest problem with treatment is the lack of effective drugs. Exciting developments have been made in this area over recent years with useful drugs being found from older agents as well as new discoveries. Patent applications are being made for novel agents and are also possible as new use for older agents such as thioridazine. A flourishing drug pipeline is critical if we are to make progress in the management of M/XDR-TB.
    Recent Patents on Anti-Infective Drug Discovery 05/2011; 6(2):77-83.
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    ABSTRACT: Obesity and ageing are both characteristics of the human population that are on the increase across the globe. It has long been established that ageing is the major risk factor for neurodegenerative conditions such as Alzheimer's disease, and it is becoming increasingly evident that obesity is another such factor. Leptin resistance or insensitivity has been uncovered as a cause of obesity, and in addition the leptin signalling system is less potent in the elderly. Taken together, these findings reveal that this molecule may be a link between neurodegeneration and obesity or ageing. It is now known that leptin has beneficial effects on both the survival and neurophysiology of the neurons that are lost in Alzheimer's disease suggesting that it may be an important research target in the quest for strategies to prevent, halt, or cure this condition.
    Current Gerontology and Geriatrics Research 01/2011; 2011:708154.