Biomedical subjects

Amanda Brown

Publications and source records attributed to Amanda Brown.

6 recordsLinked to original sources

PubMed2006

In vitro modeling of the HIV-macrophage reservoir.

Macrophages are recognized as a putative reservoir for HIV-1, but whether HIV can establish latent infection in this cell type is not known. An in vitro model using long-term cultured primary human monocyte-derived macrophages (MDM) infected with an M-tropic, enhanced green fluorescent protein (EGFP) tagged reporter virus was developed to test the hypothesis that HIV can establish a latent infection of this cell type. The EGFP-IRES-Nef cassette allowed detection of early gene transcription. The expression of GFP+ MDM was followed with time and the GFP- population was purified and analyzed for evidence of latent infection. Interestingly, in MDM cultures propagated for over two months, distinct subpopulations of infected GFP+ cells were observed and quantitated. In particular, infected MDM that displayed a high level of transcription, characterized as the GFP hi group, yet produced low levels of the late viral gene product, p24, increased with time and represented 10% of the GFP+ population in long-term cultures. The high level production of early genes such as Nef, a protein that can facilitate viral immune escape, but low level of structural proteins such as p24 in the GFP hi population suggests that a subset of infected MDM can exhibit an alternative mode of replication. The GFP- MDM population obtained by a two-step purification protocol using flow cytometry and laser ablation contained integrated provirus as assessed by Alu-LTR real-time PCR analyses. A subset of these, were replication competent as shown by their ability to express GFP and/or p24 antigen after reactivation with IL-4.

Cell Proliferation↗

PubMed2006

Language-specific and universal influences in children's syntactic packaging of Manner and Path: a comparison of English, Japanese, and Turkish.

Different languages map semantic elements of spatial relations onto different lexical and syntactic units. These crosslinguistic differences raise important questions for language development in terms of how this variation is learned by children. We investigated how Turkish-, English-, and Japanese-speaking children (mean age 3;8) package the semantic elements of Manner and Path onto syntactic units when both the Manner and the Path of the moving Figure occur simultaneously and are salient in the event depicted. Both universal and language-specific patterns were evident in our data. Children used the semantic-syntactic mappings preferred by adult speakers of their own languages, and even expressed subtle syntactic differences that encode different relations between Manner and Path in the same way as their adult counterparts (i.e., Manner causing vs. incidental to Path). However, not all types of semantics-syntax mappings were easy for children to learn (e.g., expressing Manner and Path elements in two verbal clauses). In such cases, Turkish- and Japanese-speaking children frequently used syntactic patterns that were not typical in the target language but were similar to patterns used by English-speaking children, suggesting some universal influence. Thus, both language-specific and universal tendencies guide the development of complex spatial expressions.

Adult↗

PubMed2005

HLA-A2 down-regulation on primary human macrophages infected with an M-tropic EGFP-tagged HIV-1 reporter virus.

Multiple mechanisms are used by the human immunodeficiency virus type 1 (HIV-1) to interfere with host-cell immune effector functions. The 27-kD Nef protein has been shown to down-modulate specific genes of the major histocompatibility complex class I (MHC-I) on the surface of infected primary T cells, facilitating their escape from lysis by cytolytic T lymphocytes. Macrophages, as the other major immune cell type targeted by the virus, also contribute to the transmission, persistence, and pathogenesis of HIV-1. Yet, whether Nef modulates MHC-I expression on HIV-infected primary macrophages remains unclear. Currently available infectious HIV-1 molecular clones, which express a reporter gene, only infect T cells and/or do not express Nef. To overcome these limitations, we generated macrophage-tropic green fluorescent protein (GFP)-tagged HIV-1 viruses, which express the complete viral genome, and used these to assess the expression of human leukocyte antigen (HLA)-A2 on the surface of productively infected macrophages. The reporter viral genomes were replication-competent and stable, as Nef, p24 antigen, and GFP expression could be detected by immunostaining of infected, monocyte-derived macrophages (MDM) after more than 2 months postinfection. Fluorescence-activated cell sorter analyses of infected macrophages and T cells revealed that although wild-type reporter virus infection induced a statistically significant decrease in the density of surface HLA-A2, down-regulation of HLA-A2 was not seen in cells infected with reporter viruses encoding a frameshift or a single point mutation in Nef at prolines 74P and P80. The impact of Nef on HLA-A2 surface expression in MDM was also confirmed by confocal microscopy. These results suggest that the mechanisms of HLA-A2 down-modulation are similar in primary T cells and macrophages.

CD4 Antigens↗

PubMed2005

Dietitian services are associated with improved patient outcomes and the MEDFICTS dietary assessment questionnaire is a suitable outcome measure in cardiac rehabilitation.

OBJECTIVE: The purposes of this study were to (a) examine the effectiveness of registered dietitian (RD) education and counseling on diet-related patient outcomes compared with general education provided by the cardiac rehabilitation (CR) staff, and (b) evaluate the effectiveness of the Meats, Eggs, Dairy, Fried foods, In baked goods, Convenience foods, Table fats, Snacks (MEDFICTS) score as an outcome measure in CR. METHODS: Observational study data examined from 426 CR patients discharged between January 1996 and February 2004. Groups were formed based on education source: (a) RD and (b) general education from CR staff. Baseline characteristics were compared between groups; pre/post diet-related outcomes (lipids, waist circumference, body mass index, MEDFICTS score) were compared within groups. Controlling for baseline measures and lipid-lowering medication, associations were examined between (a) RD education and diet-related outcomes and (b) ending MEDFICTS score and diet-related outcomes. RESULTS: Mean age was 62+/-11 years, 30% of patients were female, and 28% were nonwhite. At baseline, the RD group (n=359) had more dyslipidemia (88% vs 76%), more obesity (47% vs 27%), a larger waist (40+/-6 vs 37+/-5 inches), a higher body mass index (calculated as kg/m(2); 30+/-6 vs 27+/-5), a higher diet score (32+/-28 vs 19+/-19), and lower self-reported physical activity (7+/-12 vs 13+/-18 metabolic equivalent hours) (all P<.05) than the general education group (n=67). RD education was associated with improved low-density lipoprotein (r=0.13; P=.04), triglycerides (r=0.48; P=.01), and MEDFICTS score (r=0.18; P=.01). Improvements in MEDFICTS scores were correlated with improved total cholesterol, triglycerides, and waist measurements (all r=0.19; P=.04). CONCLUSIONS: Dietary education by an RD is associated with improved diet-related outcomes. The MEDFICTS score is a suitable outcome measure in CR.

Behavior Therapy↗

PubMed2004

Multiple human immunodeficiency virus type 1 Nef functions contribute to efficient replication in primary human macrophages.

The human immunodeficiency virus type 1 (HIV-1) Nef protein has been shown to accelerate viral growth kinetics in primary human T-lymphocytes and macrophages; however, the specific function(s) of Nef responsible for this phenotype in macrophages is unknown. To address this issue, mutants of a molecularly cloned macrophage-tropic isolate, HIV-1(SF162), were generated expressing single point mutations that abrogate the ability of Nef to interact with cellular kinases or mediate CD4 down-regulation. Infection of primary monocyte-derived macrophages (MDM) with these mutant viruses revealed that residues in the PXXP motif contribute to efficient replication. Interestingly, viruses expressing alleles of Nef defective in CD4 down-modulation activity retain wild-type levels of infectivity in single-round assays but exhibited delayed replication kinetics and grew to lower titres compared to the wild-type virus in MDM. These data suggest that efficient HIV-1 replication is dependent on the ability of Nef to interact with cellular kinases and remove CD4 from the surface of infected macrophages.

Amino Acid Motifs↗

PubMed2003

Using standardized patients to teach disease management skills to preclinical students: a pilot project.

BACKGROUND: Physician adherence to practice guidelines has been poor. Exposure to such guidelines is not a routine part of medical school curricula. PURPOSE: This study was designed to determine whether standardized patients could be used to teach preclinical students the skills to manage a patient with newly diagnosed diabetes mellitus. METHODS: Students were assigned a standardized patient with hyperglycemia. The students were given guidelines on the management of diabetes and told to manage the patient appropriately. Patients' charts were reviewed to determine if all cardiovascular risks were managed appropriately. RESULTS: Students successfully managed all cardiovascular risks according to published guidelines. Participants overwhelmingly believed this methodology was a valuable way to teach disease management. CONCLUSION: Second-year students can use practice guidelines to successfully manage patients with diabetes. The students' performance exceeded the standards of care found in the published literature. This problem-based approach may be an ideal way to teach disease management.

Adult↗