Biomedical subjects

Joshua Chen

Publications and source records attributed to Joshua Chen.

4 recordsLinked to original sources

PubMed2005

Endostatin binds biglycan and LDL and interferes with LDL retention to the subendothelial matrix during atherosclerosis.

Retention of lipoproteins to proteoglycans in the subendothelial matrix (SEM) is an early event in atherosclerosis. We recently reported that collagen XVIII and its proteolytically released fragment endostatin (ES) are differentially depleted in blood vessels affected by atherosclerosis. Loss of collagen XVIII/ES in atherosclerosis-prone mice enhanced plaque neovascularization and increased the vascular permeability to lipids by distinct mechanisms. Impaired endothelial barrier function increased the influx of lipoproteins across the endothelium; however, we hypothesized that enhanced retention might be a second mechanism leading to the increased lipid content in atheromas lacking collagen XVIII. We now demonstrate a novel property of ES that binds both the matrix proteoglycan biglycan and LDL and interferes with LDL retention to biglycan and to SEM. A peptide encompassing the alpha coil in the ES crystal structure mediates the major blocking effect of ES on LDL retention. ES inhibits the macrophage uptake of biglycan-associated LDL indirectly by interfering with LDL retention to biglycan, but it has no direct effect on the macrophage uptake of native or modified lipoproteins. Thus, loss of ES in advanced atheromas enhances lipoprotein retention in SEM. Our data reveal a third protective role of this vascular basement membrane component during atherosclerosis.

Animals↗

PubMed2005

A mobile trauma database with charge capture.

BACKGROUND: Charge capture plays an important role in every surgical practice. We have developed and merged a custom mobile database (DB) system with our trauma registry (TRACS), to better understand our billing methods, revenue generators, and areas for improved revenue capture. METHODS: The mobile database runs on handheld devices using the Windows Compact Edition platform. The front end was written in C# and the back end is SQL. The mobile database operates as a thick client; it includes active and inactive patient lists, billing screens, hot pick lists, and Current Procedural Terminology and International Classification of Diseases, Ninth Revision code sets. Microsoft Information Internet Server provides secure data transaction services between the back ends stored on each device. Traditional, hand written billing information for three of five adult trauma surgeons was averaged over a 5-month period. Electronic billing information was then collected over a 3-month period using handheld devices and the subject software application. One surgeon used the software for all 3 months, and two surgeons used it for the latter 2 months of the electronic data collection period. This electronic billing information was combined with TRACS data to determine the clinical characteristics of the trauma patients who were and were not captured using the mobile database. RESULTS: Total charges increased by 135%, 148%, and 228% for each of the three trauma surgeons who used the mobile DB application. The majority of additional charges were for evaluation and management services. Patients who were captured and billed at the point of care using the mobile DB had higher Injury Severity Scores, were more likely to undergo an operative procedure, and had longer lengths of stay compared with those who were not captured. CONCLUSION: Total charges more than doubled using a mobile database to bill at the point of care. A subsequent comparison of TRACS data with billing information revealed a large amount of uncaptured patient revenue. Greater familiarity and broader use of mobile database technology holds the potential for even greater revenue capture.

Accounting↗

PubMed2003

Long-term efficacy, safety, and tolerability of indinavir-based therapy in protease inhibitor-naive adults with advanced HIV infection.

A double-blind, randomized study of zidovudine-experienced, PI- and lamivudine-naive adults with baseline CD4 cell counts of < or =50 cells/mm3 had demonstrated that the HIV suppression achieved with zidovudine, lamivudine, and indinavir therapy was superior to that achieved with dual-nucleoside or indinavir-only regimens after 24 weeks of therapy. In a 192-week extension of the study, 371 participants received open-label indinavir with or without other antiretroviral drugs. One hundred and eight subjects were originally randomized to receive triple therapy. After 216 weeks, the proportion of subjects with HIV RNA levels of <500 copies/mL were 34%, according to a general estimating equation analysis, 92%, according to an observed data analysis, and 24%, according to an intention-to-treat analysis counting noncompleters as failures; the proportions of subjects with HIV RNA levels of <50 copies/mL were 31%, 85%, and 22%, respectively. Hyperbilirubinemia (experienced by 31% of subjects), nausea (17%), abdominal pain (14%), and nephrolithiasis (13%) were the most common drug-related adverse events during the extension.

Adult↗

PubMed2003

Treatment with indinavir, efavirenz, and adefovir after failure of nelfinavir therapy.

A prospective, open-label study was conducted to assess the response to indinavir, efavirenz, and adefovir in human immunodeficiency virus (HIV)-infected patients experiencing viral rebound while receiving therapy with nelfinavir-containing regimens, to determine whether the protease genotype influenced the outcome of the salvage regimen. Genotyping from 29 nelfinavir failures revealed D30N in 17 (59%) and L90M in 11 (38%) cases. Suppression to <400 viral RNA copies/mL was achieved at week 48 in 56% of patients with the D30N virus versus 18% of patients with the L90M virus.

Adenine↗