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Search Results: 1 - 10 of 402965 matches for " Melinda M. Dean "
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Significance of Mannose-Binding Lectin Deficiency and Nucleotide-Binding Oligomerization Domain 2 Polymorphisms in Staphylococcus aureus Bloodstream Infections: A Case-Control Study
Michael Osthoff, Hue Mun Au Yong, Melinda M. Dean, Damon P. Eisen
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0076218
Abstract: Background Pathways coordinated by innate pattern recognition receptors like mannose-binding lectin (MBL) and nucleotide-binding oligomerization domain 2 (NOD2) are among the first immune responses to Staphylococcus aureus (S. aureus) bloodstream infections (BSI) in animal models, but human data are limited. Here, we investigated the role of MBL deficiency and NOD2 mutations in the predisposition to and severity of S. aureus BSI. Patients and Methods A matched case-control study was undertaken involving 70 patients with S. aureus BSI and 70 age- and sex-matched hospitalized controls. MBL levels, MBL2 and NOD2 polymorphisms were analyzed. Results After adjusting for potential confounders, MBL deficiency (<0.5 μg/ml) was found less frequently in cases than controls (26 vs. 41%, OR 0.4, 95% confidence interval (CI) 0.20-0.95, p=0.04) as were low producing MBL genotypes (11 vs. 23%, OR 0.2, 95% CI 0.08-0.75, p=0.01), whereas NOD2 polymorphisms were similarly distributed. Cases with NOD2 polymorphisms had less organ dysfunction as shown by a lower SOFA score (median 2.5 vs. 4.5, p=0.02), whereas only severe MBL deficiency (<0.1 μg/ml) was associated with life-threatening S. aureus BSI (OR 5.6, 95% CI 1.25-24.85, p=0.02). Conclusions Contrary to animal model data, our study suggests MBL deficiency may confer protection against acquiring S. aureus BSI. NOD2 mutations were less frequently associated with multi-organ dysfunction. Further human studies of the innate immune response in S. aureus BSI are needed to identify suitable host targets in sepsis treatment.
Oxidative Stress Decreases Functional Airway Mannose Binding Lectin in COPD
Hai B. Tran, Jessica Ahern, Greg Hodge, Phillip Holt, Melinda M. Dean, Paul N. Reynolds, Sandra Hodge
PLOS ONE , 2014, DOI: 10.1371/journal.pone.0098571
Abstract: We have previously established that a defect in the ability of alveolar macrophages (AM) to phagocytose apoptotic cells (efferocytosis) and pathogens is a potential therapeutic target in COPD. We further showed that levels of mannose binding lectin (MBL; required for effective macrophage phagocytic function) were reduced in the airways but not circulation of COPD patients. We hypothesized that increased oxidative stress in the airway could be a cause for such disturbances. We therefore studied the effects of oxidation on the structure of the MBL molecule and its functional interactions with macrophages. Oligomeric structure of plasma derived MBL (pdMBL) before and after oxidation (oxMBL) with 2,2′-azobis(2-methylpropionamidine)dihyd?rochroride(AAPH) was investigated by blue native PAGE. Macrophage function in the presence of pd/oxMBL was assessed by measuring efferocytosis, phagocytosis of non-typeable Haemophilus influenzae (NTHi) and expression of macrophage scavenger receptors. Oxidation disrupted higher order MBL oligomers. This was associated with changed macrophage function evident by a significantly reduced capacity to phagocytose apoptotic cells and NTHi in the presence of oxMBL vs pdMBL (eg, NTHi by 55.9 and 27.0% respectively). Interestingly, oxidation of MBL significantly reduced macrophage phagocytic ability to below control levels. Flow cytometry and immunofluorescence revealed a significant increase in expression of macrophage scavenger receptor (SRA1) in the presence of pdMBL that was abrogated in the presence of oxMBL. We show the pulmonary macrophage dysfunction in COPD may at least partially result from an oxidative stress-induced effect on MBL, and identify a further potential therapeutic strategy for this debilitating disease.
Thinking inside the Box: Tissue Culture for Plant Propagation in a Key Ecological Species, Andropogon gerardii  [PDF]
Ava M. Hoffman, Melinda D. Smith
American Journal of Plant Sciences (AJPS) , 2018, DOI: 10.4236/ajps.2018.910144
Abstract: Intraspecific diversity has widespread effects on ecological communities and ecosystems. To elucidate the mechanisms underlying these effects, manipulative studies require a rigorous and efficient empirical approach. Yet, replicating sufficient numbers of genetically identical individuals remains a challenge. As a result, we are limited in our understanding of the mechanisms underlying the ecological effects of intraspecific diversity. In contrast, large sample sizes are routinely produced in horticultural research using micropropagation, or tissue culture. In order to determine the potential usefulness of micropropagation technique for ecological studies, we investigated the efficiency and efficacy of micropropagation on the ecologically important non-model C4 grass species, Andropogon gerardii. Our preliminary results demonstrate that micropropagation is a rapid and effective technique for producing large numbers of genetically identical clones at up to 100 times the rate of traditional propagation. Key intraspecific differences among clones of A. gerardii were also retained through the micropropagation process. Given that traditional techniques used to test the effects of intraspecific diversity manipulations are time-limiting (greenhouse propagation) or can be biologically misrepresentative (seeds) for some species, we suggest that micropropagation might be a powerful tool for advancing ecological genetics studies in many plant systems.
Insights into the High Temperature Superconducting Cuprates from Resonant Inelastic X-ray Scattering
M. P. M. Dean
Physics , 2014, DOI: 10.1016/j.jmmm.2014.03.057
Abstract: Recent improvements in instrumentation have established resonant inelastic x-ray scattering (RIXS) as a valuable new probe of the magnetic excitations in the cuprates. This article introduces RIXS, focusing on the Cu $L_3$ resonance, and reviews recent experiments using this technique. These are discussed in light of other experimental probes such as inelastic neutron scattering and Raman scattering. The success of these studies has motivated the development of several new RIXS spectrometers at synchrotrons around the world that promise, among other improvements, 5-10 times better energy resolution. We finish by outlining several key areas which hold promise for further important discoveries in this emerging field.
Les variants colorés en race Mérinos d'Arles II. – Facteurs isolables chez les descendants: leur fréquence dans la race
JJ Lauvergne, M Danzart, Melinda J Burrill
Genetics Selection Evolution , 1981, DOI: 10.1186/1297-9686-13-3-219
Structural Examination of 6-Methylsulphonylphenanthro- [9,10-C]-furan-1(3H)-one—A Rofecoxib Degradation Product
Pamela M. Dean
Pharmaceuticals , 2010, DOI: 10.3390/ph3020369
Abstract: In the attempt to discover a new polymorph of rofecoxib (Vioxx?), an unexpected product resulted. The product was characterised by chemical composition, thermal behaviour and structure and found to be 6-methylsulphonylphenanthro-[9,10-C] furan-1(3 H)-one, a photo-cyclization degradation product of rofecoxib. This is a significant finding because it indicates that without appropriate control of the recrystallisation procedures, the structural integrity of rofecoxib may be seriously compromised.
A General Hermitian Nonnegative-Definite Solution to the Matrix Equation AXB = C  [PDF]
Phil D. Young, Dean M. Young, Marsha M. Young
Advances in Linear Algebra & Matrix Theory (ALAMT) , 2017, DOI: 10.4236/alamt.2017.71002
Abstract: We derive necessary and sufficient conditions for the existence of a Hermitian nonnegative-definite solution to the matrix equation AXB = C. Moreover, we derive a representation of a general Hermitian nonnegative-definite solution. We then apply our solution to two examples, including a comparison of our solution to a proposed solution by Zhang in [1] using an example problem given from [1]. Our solution demonstrates that the proposed general solution from Zhang in [1] is incorrect. We also give a second example in which we derive the general covariance structure so that two matrix quadratic forms are independent.
Are neonatal morbidities associated with no prenatal care different from those associated with inadequate prenatal care?  [PDF]
Ekwutosi M. Okoroh, Dean V. Coonrod, Kristina Chapple, David Drachman
Open Journal of Obstetrics and Gynecology (OJOG) , 2012, DOI: 10.4236/ojog.2012.22018
Abstract: Objective: Compare neonatal morbidities in women with no prenatal care, and women with inadequate prenatal care, to those with adequate prenatal care. Methods: Retrospective cohort study of neonatal morbidities of 3 exposure groups. Group 1: No prenatal care; Group 2: Inadequate prenatal care; Group 3: Intermediate/adequate prenatal care. Results: 2.5%, 23.3% and 74.1% of subjects (N = 264,138) were in Groups 1, 2 and 3 respectively. Severe neonatal morbidity was more common in Group 1, followed by Group 2, and least common in Group 3. After controlling for gestational age and birth weight, most of these differences were attenuated and not significant except for the following Group 1 vs Group 3 comparisons: meconium aspiration, odds ratio (OR) 2.15 and 95% confidence interval (CI) 1.39 - 3.33; suspected sepsis, OR 1.30 and CI 1.13 - 1.49; proven viral sepsis, OR 2.23 and CI 1.24 - 4.00. Conclusions: Severe neonatal morbidity was most common in those with no prenatal care followed by those with inadequate prenatal care. For most neonatal morbidities, this could largely be explained by gestational age and birth weight differences, but for some neonatal morbidities (meconium aspirations, viral sepsis and dysmorphic features) the impact of no prenatal care persisted after adjustment for these factors.
Hands-On Parent Empowerment (HOPE) Project: Comparing Implementation in Social Service Centres and Preschools  [PDF]
Cynthia Leung, Sandra K M Tsang, Suzanne Dean
Advances in Applied Sociology (AASoci) , 2012, DOI: 10.4236/aasoci.2012.23025
Abstract: This project examined the effectiveness and implementation of an early intervention program for children from new immigrant families in Hong Kong in two delivery settings, preschools and social services centres. Participants included 141 new immigrant mothers with preschool children, from 13 preschools and two social services centres. The preschool participants were randomized into an intervention group (30-session HOPE program) and a comparison group (six-session program) at the preschool level, while participants from the two social services centres attended the 30-session HOPE program. Results indicated that the HOPE participants in preschools and social services centres reported lower post-intervention child behavior problem scores than the comparison group. Preschool HOPE participants reported higher post-intervention social support than the social services HOPE participants and comparison group participants. Qualitative information from preschool principals and centre supervisors indicated different dynamics within the two settings. Implications and suggestions for service delivery were discussed.
Spatiotemporal Cattle Data—A Plea for Protocol Standardization  [PDF]
Dean M. Anderson, Rick E. Estell, Andres F. Cibils
Positioning (POS) , 2013, DOI: 10.4236/pos.2013.41012

It was not until the end of the 1990’s that animal born satellite receivers catapulted range cattle ecology into the 21st century world of microchip technology with all of its opportunities and challenges. With the global navigation satellite system (GNSS), insight about how cattle use a landscape is being revealed from previously unknown temporal and spatial behaviors. The most common system to date for studying ungulate movement is the global positioning system (GPS). With its use has come a clarity and completeness in documenting spatial and temporal data in new and exciting ways that offer almost unlimited possibilities to better understand and manage economic and societal returns from animal dominated landscapes. However, its use on free-ranging cattle is not without challenges, some of which are yet to be optimally solved. To maximize the usefulness of GNSS data, consideration must be given to: 1) developing a standardized protocol for reporting and analyzing research that facilitates interpretation of results across different ecosystems; 2) develop optimum ranges over which to collect satellite fixes depending upon the particular behaviors of interest; and 3) concurrently develop electronic hardware and equipment platforms that are easily deployed on animals and that are light, robust, and can be worn by cattle for extended periods of time without human intervention (e.g., changing batteries). Once data are collected, appropriate geographic information system (GIS) based models should be used to produce a series of products that can be used to implement flexible management strategies, some of which may support methodologies that are yet to be commercialized and adopted into future plant-animal interface management routines.

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