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Search Results: 1 - 10 of 9034 matches for " Elizabeth Kiefer "
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The Influence of Culture Medium Type on Cellular Phenotype of Canine Adipose Derived Stem Cells  [PDF]
Kristina M. Kiefer, G. Elizabeth Pluhar, Michael G. Conzemius, Timothy D. O’Brien
Open Journal of Regenerative Medicine (OJRM) , 2014, DOI: 10.4236/ojrm.2014.31004

Canine adipose derived stem cells (ASCs) hold a great promise for the therapy of osteoarthritis in veterinary medicine. Current therapy is an autologous, stromal vascular fraction. Allogeneic ASCs provide many advantages, including efficient, cost-effective treatments while eliminating a surgical procedure in a diseased animal. Cultured ASCs can be expanded and characterized, allowing selection of desirable qualities. Use of allogeneic ASCs requires selection of a culture medium that provides consistent, desirable cellular products. The supplements within a medium can greatly influence cellular phenotypes. We hypothesized that medium type influenced cellular phenotype, allowing selection of a specified cellular product for clinical applications. We evaluated ASCs derived from adipose tissue of six dogs, assessing mRNA expression of proinflammatory: interleukin-1b, cyclooxygenase-2, and anti-inflammatory mediators: tissue inhibitor metalloproteinase-2 and interleukin -1 receptor antagonist, via quantitative RT-PCR prior to, and following culture in five cell culture media: basic cell growth medium (BGM), Keratinocyte N acetyl-L-cysteine supplemented (KNAC) medium, Multipotent Adult Progenitor Cell (MAPC) medium, serum free medium (SFM) and xeno-free medium. Major histocompatability complex I (MHCI), major histocompatability complex II (MHCII), CD44 and CD90 immunophenotypes were assessed via flow cytometry analysis. Tri-lineage differentiation (bone, adipose and cartilage tissue) was utilized to verify multipotency. SFM and xeno-free culture conditions did not produce cell expansion sufficient to assess phenotype. ASCs prior to culture had wide variability in all mediator levels, while culturing in the remaining conditions resulted in more predictable expression levels of inflammatory mediators, with a decrease in all levels. Cultured ASCs retained expression of cell surface markers MHCI, CD44 and CD90, while decreasing MHCII expression levels. KNAC and MAPC medium conditions consistently produced

Simultaneous Echo Refocused Magnetization Transfer Imaging  [PDF]
Claus Kiefer
Open Journal of Medical Imaging (OJMI) , 2014, DOI: 10.4236/ojmi.2014.43021
Abstract: Purpose: To increase the efficiency of densely encoded magnetization transfer imaging of the brain, we time-multiplex multiple slices within the same readout using simultaneous echo refocusing FLASH imaging with magnetization transfer (MT) preparation (MT-SER-FLASH). Materials and Methods: Inefficiency in total scan time results from the number of frequency samples needed for sufficient quality of quantitative parameter maps for a binary spin bath model. We present a highly efficient multiplexing method, simultaneous echo refocused magnetization transfer imaging (MT-SER-FLASH) for reducing the total scan time of MT imaging by one-third. The specific absorption rate (SAR) was also reduced by reducing the number of MT-pulses per volume. Results: 2D-MT-SER-FLASH is performed in 19 minutes rather than 1 hour, acceptable for routine clinical application. The SAR could be reduced to 69% instead of more than 100% with a standard 2D or 3D-FLASH with MT-preparation. Conclusion: The net reduction of scan time and SAR enables the use of quantitative model based magnetization transfer imaging within a clinical environment.
Modelling Magnetization Transfer Considering Spin-Locking Effects  [PDF]
Claus Kiefer
Open Journal of Medical Imaging (OJMI) , 2014, DOI: 10.4236/ojmi.2014.44027
Abstract: Purpose: Recently it was demonstrated that spin-locking (SL) effects can manifest as pseudo magnetization transfer (MT). To our best knowledge the MT models proposed so far cannot distinguish between saturation effects caused by the MT preparation pulses and SL phenomena. Therefore a new MT model is proposed. Materials and Methods: A binary spin-bath model for magnetization transfer was extended in that sense that SL effects are considered. The new modified spin bath model was tested for a phantom with different agar concentrates (2%, 4%, 8%) and a MnCl2 (0.3 mM) solution. Results: The mean fitting error is 3.2 times lower for the modified model compared to the original model. Especially the parameter F for the fractional part of the bounded proton pool describes the situation for the MnCl2 (F = 0) better than the original model (F = 0.004). Conclusion: The proposed mathematical modifications of the binary spin-bath model considering SL seem to be a step in the right direction in that sense that the effects associated with SL are not interpreted as magnetization transfer.
Elucidating potentially significant genomic regions involved in the initiation and progression of undifferentiated pleomorphic sarcoma
Paul Kurywchak,Jeff Kiefer,Elizabeth Lenkiewicz,Lisa Evers
Rare Tumors , 2013, DOI: 10.4081/rt.2013.e14
Abstract: Sarcomas are cancers that arise in soft tissues or bone and make up a small percentage of malignancies. In an effort to identify potential genetic targets for therapy, this study explores the genomic landscape of a metastatic undifferentiated pleomorphic sarcoma (UPS) with spindle cell morphology. Thick sections (50 μm) of formalin-fixed, paraffin-embedded tissue from a primary, recurrent, and metastatic tumor were collected and processed from a single patient for DNA content-based flow-sorting and analyses. Nuclei of diploid and aneuploid populations were sorted from the malignant tissues and their genomes interrogated with array comparative genomic hybridization. The third sample was highly degraded and did not contain any intact ploidy peaks in our flow assays. A 2.5N aneuploid population was identified in the primary and recurrent sample. We detected a series of shared and unique genomic aberrations in the sorted aneuploid populations. The patterns of aberrations suggest that two similar but independent clonal populations arose during the clinical history of this rare tumor. None of these aberrations were detected in the matching sorted diploid samples. The targeted regions of interest might play a role in UPS and may lead to clinical significance with further investigation.
Disruption of Mycobacterium smegmatis Biofilms Using Bacteriophages Alone or in Combination with Mechanical Stress  [PDF]
Brendan Kiefer, John L. Dahl
Advances in Microbiology (AiM) , 2015, DOI: 10.4236/aim.2015.510073
Abstract: Environmental mycobacteria are capable of forming biofilms in low-nutrient environments, and these biofilms may act as reservoirs for opportunistic infections. The purpose of this study was to determine if bacteriophages could disrupt existing biofilms of acid-fast staining Mycobacterium smegmatis. Using the MBEC 96-well plastic peg assay system, M. smegmatis biofilms were created and then tested for their stability in the presence of mycobacteriophages isolated from a Minnesota sphagnum peat bog. All phages tested were lytic and were observed to have weak, intermediate, and strong abilities to disrupt M. smegmatis biofilms. The formation of biofilms was severely impaired in the presence of mycobacteriophages. Phage treatment was also shown to augment?M. smegmatis biofilm disruption by mechanical forces of sonication or water flow. Our study shows that, as with biofilms of Gram-positive and Gram-negative bacteria, mycobacterial biofilms are also susceptible to destruction by bacteriophages.
Association of Pre-Treatment Nutritional Status with Change in CD4 Count after Antiretroviral Therapy at 6, 12, and 24 Months in Rwandan Women
Elizabeth Kiefer, Donald R. Hoover, Qiuhu Shi, Jean-Claude Dusingize, Mardge Cohen, Eugene Mutimura, Kathryn Anastos
PLOS ONE , 2011, DOI: 10.1371/journal.pone.0029625
Abstract: Background Body mass index (BMI) independently predicts mortality in studies of HIV infected patients initiating antiretroviral therapy (ART). We hypothesized that poorer nutritional status would be associated with smaller gains in CD4 count in Rwandan women initiating ART. Methods and Findings The Rwandan Women's Interassociation Study and Assessment, enrolled 710 ART-na?ve HIV-positive and 226 HIV-negative women in 2005 with follow-up every 6 months. The outcome assessed in this study was change in CD4 count at 6, 12, and 24 months after ART initiation. Nutritional status measures taken prior to ART initiation were BMI; height adjusted fat free mass (FFMI); height adjusted fat mass (FMI), and sum of skinfold measurements. 475 women initiated ART. Mean (within 6 months) pre-ART CD4 count was 216 cells/μL. Prior to ART initiation, the mean (±SD) BMI was 21.6 (±3.78) kg/m2 (18.3% malnourished with BMI<18.5); and among women for whom the following were measured, mean FFMI was 17.10 (±1.76) kg/m2; FMI 4.7 (±3.5) kg/m2 and sum of skinfold measurements 4.9 (±2.7) cm. FFMI was significantly associated with a smaller change in CD4 count at 6 months in univariate analysis (?6.7 cells/uL per kg/m2, p = 0.03) only. In multivariate analysis after adjustment for covariates, no nutritional variable was associated with change in CD4 count at any follow up visit. Conclusion In this cohort of African women initiating ART, no measure of malnutrition prior to ART was consistently associated with change in CD4 count at 6, 12, and 24 months of follow up, suggesting that poorer pre-treatment nutritional status does not prevent an excellent response to ART.
Association of Serum Albumin with Markers of Nutritional Status among HIV-Infected and Uninfected Rwandan Women
Jean-Claude Dusingize, Donald R. Hoover, Qiuhu Shi, Eugene Mutimura, Elizabeth Kiefer, Mardge Cohen, Kathryn Anastos
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0035079
Abstract: Introduction The objectives of this study are to address if and how albumin can be used as an indication of malnutrition in HIV infected and uninfected Africans. Methods In 2005, 710 HIV-infected and 226 HIV-uninfected women enrolled in a cohort study. Clinical/demographic parameters, CD4 count, albumin, liver transaminases; anthropometric measurements and Bioelectrical Impedance Analysis (BIA) were performed. Malnutrition outcomes were defined as body mass index (BMI), Fat-free mass index (FFMI) and Fat mass index (FMI). Separate linear predictive models including albumin were fit to these outcomes in HIV negative and HIV positive women by CD4 strata (CD4>350,200–350 and <200 cells/μl). Results In unadjusted models for each outcome in HIV-negative and HIV positive women with CD4>350 cells/μl, serum albumin was not significantly associated with BMI, FFMI or FMI. Albumin was significantly associated with all three outcomes (p<0.05) in HIV+ women with CD4 200–350 cells/μl, and highly significant in HIV+ women with CD4<200 cells/μl (P<0.001). In multivariable linear regression, albumin remained associated with FFMI in women with CD4 count<200 cells/μl (p<0.01) but not in HIV+ women with CD4>200. Discussion While serum albumin is widely used to indicate nutritional status it did not consistently predict malnutrition outcomes in HIV- women or HIV+ women with higher CD4. This result suggests that albumin may measure end stage disease as well as malnutrition and should not be used as a proxy for nutritional status without further study of its association with validated measures.
Quantum cosmology and the arrow of time
Kiefer, Claus;
Brazilian Journal of Physics , 2005, DOI: 10.1590/S0103-97332005000200014
Abstract: although most fundamental laws are invariant under time reversal, experience exhibits the presence of irreversible phenomena - the arrows of time. their origin lies in cosmology, and i argue that only quantum cosmology can provide the appropriate formal framework. after briefly reviewing the formalism, i discuss how a simple and natural boundary condition can lead to the observed arrows of time. this yields at the same time interesting consequences for black holes.
Residential Location Choice: The Role of a Taste for Similarity
Hua Kiefer
International Journal of Economics and Finance , 2012, DOI: 10.5539/ijef.v4n9p34
Abstract: This paper examines the importance of social interactions on a household's location decision. The theory argues that individuals' utility will be greater when socially interacting with similar others. The hypothesis that a household desires to find a good community match is tested through the application of a discrete residential location choice model. In addition, this paper also tests Tiebout's hypothesis that households search for a community where their benefits from local public goods will exceed their local tax costs. The findings tend to support both hypotheses, indicating that a household prefers neighbors with a similar socio-economic background and somewhat larger houses.
A poética de Edgar Allan Poe
Kiefer, Charles
Letras de Hoje , 2010,
Abstract: O estudo abrange o início da vida literária de Edgar Allan Poe como crítico do periódico Graham’s Magazine. Ao produzir resenhas sobre Nathanael Hawthorne, Poe elabora uma síntese de suas concep es a respeito do conto. Para o autor a vantagem do conto, como gênero, é que ele permite uma leitura totalizadora. O exame das resenhas de Poe torna possível uma aproxima o entre a poética do autor norte-americado com a de Aristóteles.
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