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Biomedical subjects

Chuong D Hoang

Publications and source records attributed to Chuong D Hoang.

11 recordsLinked to original sources
PubMed2006

Technology-enhanced interactive surgical education.

BACKGROUND: Our goal was to create surgical resident centered, interactive teaching modules rich in basic science and clinical content directly pertinent to patient care and surgical techniques that would facilitate education in the 80-h work week environment. METHODS: A systematic evaluation of available instructional tools determined that a technology-enhanced approach can effectively and efficiently address the new requirements for resident learning. An extensive evaluation of available technology determined the technology best suited to teaching the adult surgical learner. RESULTS: An on-line, multimedia-based surgical education environment using WebCT Vista (WebCT, Inc., Lynnfield, MA) and Macromedia Breeze (Adobe Systems, Inc., San Jose, CA) software packages was implemented. The concept was constructed on tenets of adult learning theory and based on the APDS curriculum and ACGME core competencies. WebCT Vista serves as virtual scaffolding, and Macromedia Breeze functions to deliver content rich multimedia audio and visual presentations. Core subdiscipline teaching modules were created, comprised of individual lecture packets developed by faculty. Components for testing pre/post module knowledge, feedback and evaluations are built-in. The online nature allows for 24-h access at locations that are convenient to the resident. CONCLUSIONS: Teaching modules enable maximal trainee and instructor flexibility, which translates into optimal adult learning and teaching. Lecture packets can be conveyed to all residents with unlimited availability in the virtual domain. Further refinement and continued implementation will help fill the void in direct didactic teaching left by mandated work hour restrictions, allowing for more efficient learning and teaching. There is great potential for broad application of the concept and technology to other training programs.

Adult↗
PubMed2006

Wedge gastroplasty and reinforced crural repair: important components of laparoscopic giant or recurrent hiatal hernia repair.

OBJECTIVE: Laparoscopic repair of a giant hiatal hernia (>50% of the stomach above the diaphragm) is associated with short-term recurrence rates of 12% to 42%. Recurrent hiatal hernias often have significantly altered anatomy, making laparoscopic repair challenging. We hypothesized that increasing intra-abdominal esophageal length by means of Collis wedge gastroplasty, complete fat-pad dissection, hernia-sac excision, and primary reinforced crural repair would minimize short-term recurrence and provide adequate symptomatic relief. METHODS: From January 1, 2001, though May 1, 2005, 61 patients underwent laparoscopic repair of a giant or recurrent hiatal hernia with a Collis wedge gastroplasty and Nissen fundoplication. Symptomatic outcomes were assessed with a validated questionnaire (Gastroesophageal Reflux Disease Health-Related Quality of Life). We obtained postoperative radiographic imaging to objectively assess anatomic results at a median of 1.13 years. RESULTS: Of the 61 patients, 12 (20%) were referred to our institution after previous repairs. Operating time averaged 308 +/- 103 minutes. The median hospital stay was 4 days. Postoperative complications occurred in 5 (8.2%) patients. One (1.6%) patient died of cardiac complications. Postoperatively, 52 (85%) patients completed the questionnaire with mean a Gastroesophageal Reflux Disease Health-Related Quality of Life questionnaire score of 1.15 +/- 2.78 (scale, 0-45; 0 = asymptomatic). Overall, 51 (98%) of the 52 respondents were satisfied with their surgical outcome. Postoperative radiographic data were available for 54 (89%) patients. We identified no recurrences at 1-month follow-up, and only 4.7% (2/42) had evidence of radiographic recurrence at 1 year or more. CONCLUSIONS: Consistent use of a Collis wedge gastroplasty with reinforced crural repair minimizes short-term recurrence after minimally invasive giant hiatal hernia repair. Symptomatic results are excellent in most patients.

Diaphragm↗
PubMed2005

Analysis of paired primary lung and lymph node tumor cells: a model of metastatic potential by multiple genetic programs.

BACKGROUND: The current paradigm of metastasis proposes that rare cells within primary tumors acquire metastatic capability via sequential mutations, suggesting that metastases are genetically dissimilar from their primary tumors. We tested this hypothesis by examining the molecular differences, if any, between primary tumor cells and matched lymph node metastatic cells in human non-small-cell lung carcinoma specimens. METHODS: We performed transcriptional profiling studies on malignant cells from 11 pairs of stage III tumors and their tumor-positive lymph nodes using multiple, complementary analytic techniques. To confirm the overall validity of microarray data, we used real-time polymerase chain reaction. RESULTS: The molecular signature of nodal metastasis was a composite of two paradoxical, but not mutually exclusive, expression patterns: metastatic cells are: (1) different from their primary tumor cells based on a few genes and (2) genetically similar, overall, to their primary tumor cells. Consequently, we found a 27-gene subset sufficient to differentiate nodal metastatic cells from primary tumor cells. CONCLUSIONS: Thus, we concluded that a more accurate model of metastatic potential is based on a global primary tumor expression pattern along with the appearance of distinct metastatic variants. The 27-gene signature differentiating primary tumors from their metastatic cells may define non-small-cell lung carcinoma nodal metastatic potential.

Carcinoma, Non-Small-Cell Lung↗
PubMed2005

Short esophagus and esophageal stricture.

Short esophagus and peptic esophageal stricture are complications of chronic severe GERD. Short esophagus is properly diagnosed by an objective,intraoperative assessment after appropriate dissection of the GEJ. A laparoscopic Collis gastroplasty combined with an antireflux procedure comprises effective therapy. Peptic stricture should be addressed with an initial course of dilator therapy and optimization of antiacid medication. Consideration is given to an antireflux procedure if conservative therapy fails. Laparoscopic techniques have proven to be safe and effective in treating short esophagus and peptic stricture.

Chronic Disease↗
PubMed2005

An unusual rectosigmoid mass: endometrioid adenocarcinoma arising in colonic endometriosis: case report and literature review.

Malignant transformation is an infrequent complication of endometriosis. The ovary is the primary site in 79 per cent of cases, and extragonadal sites are identified in 21 per cent. Primary involvement of these types of tumors with the colon and/or rectum is a rare clinical entity. Endometrioid carcinoma is a common histologic type that remains a diagnostic challenge-the main differential diagnosis includes colorectal carcinomas. We report a case of malignant transformation arising in colonic endometriosis. The patient had a total abdominal hysterectomy and bilateral salpingo-oophorectomy 10 years before she presented with hematochezia. The patient was ultimately treated by surgical resection. Immunohistochemical staining in addition to the usual histopathology was critical for accurate diagnosis of this endometriosis-associated intestinal tumor.

Carcinoma, Endometrioid↗
PubMed2004

Selective activation of insulin receptor substrate-1 and -2 in pleural mesothelioma cells: association with distinct malignant phenotypes.

Molecular mechanisms active in transforming human pleural cells remain incompletely understood. Our previous microarray analysis of malignant pleural mesothelioma revealed alterations in components of the insulin-like growth factor (IGF) system, implicating this signaling axis in tumorigenesis. Therefore, in this current study, we characterized the molecular phenotype and investigated the key signaling pathways of the IGF system in malignant pleural mesothelioma specimens. For the major IGF components, we assessed mRNA abundance and total protein levels. We measured IGF-I ligand-dependent activation of signaling pathways downstream of the type I IGF receptor in a subset of malignant pleural mesothelioma cell lines and determined the corresponding biological consequences. At the transcriptional level, we observed consistent changes in IGF components that may contribute to a malignant phenotype. IGF-I stimulation of cells resulted in enhanced activation of type I IGF receptor and IRS adaptor proteins. Differential activation of IRS-1 signaling was associated with cell growth, whereas IRS-2 signaling was associated with cell motility. Thus, these data suggest that multiple mechanisms likely contribute to malignant pleural mesothelioma tumorigenesis. Therefore, IGF system components represent novel malignant pleural mesothelioma therapeutic targets for investigation.

Cell Line, Transformed↗
PubMed2004

Gene expression profiles in esophageal adenocarcinoma.

BACKGROUND: The incidence of esophageal adenocarcinoma (EAC) has risen dramatically in the last two decades. As with other malignancies, changes in gene expression play a key role in the development and progression of these tumors. METHODS: Microarray analysis was used to study gene expression of 12,000 genes in EAC specimens. Adenocarcinoma tissue samples (n = 10) and controls of normal stomach (n = 6) and esophageal (n = 7) mucosa were collected fresh, then rapidly frozen in liquid nitrogen. The messenger ribonucleic acid (mRNA) from the samples was isolated, reverse transcribed, and used to generate biotin-labeled mRNA fragments, which were hybridized to Affymetrix U95 gene chips (AME Bioscience, Norway) for analysis. Additional samples analyzed included tissue containing dysplastic Barrett's epithelium from three patients, metastatic lymph nodes from two patients with EAC, one squamous carcinoma, and two esophageal cancer cell lines. Samples were segregated into groups with similar patterns of gene expression using clustering algorithms and gene sets that differentiated tumors from normal tissue were generated. RESULTS: There were 150 genes that were fourfold up regulated and 183 genes that were fourfold down regulated in the esophageal adenocarcinoma specimens, as compared to normal esophageal mucosa tissue controls. Using paired specimens (n = 5) and the paired t-test (p Value of 0.05) as a filter, only 64 genes were fourfold up regulated and 110 were fourfold down regulated. These groups included cytoskeletal, cell adhesion, tumor suppressor, and signal transduction genes. Hierarchical clustering segregated the samples into the expected divisions. The esophageal cancer cell lines, OE19 and OE33, clustered separately from the EAC specimens. Extremely high gene expression levels of the ERBB2 gene, seen in the microarray analysis of the 2 cell lines, correlated with amplification of the gene determined by Southern blotting. CONCLUSIONS: Gene expression patterns from a small subset of genes distinguish EAC specimens from normal controls. This technique can rapidly identify genes for targeted chemotherapeutic approaches to cancer treatment.

Adenocarcinoma↗
PubMed2004

Expression profiling of non-small cell lung carcinoma identifies metastatic genotypes based on lymph node tumor burden.

OBJECTIVE: This study hypothesized that non-small cell lung carcinoma cells from primary tumors isolated by laser capture microdissection would exhibit gene expression profiles associated with graded lymph node metastatic cell burden. METHODS: Non-small cell lung carcinoma tumors (n = 15) were classified on the basis of nodal metastatic cell burden by 2 methods, obtaining 3 groups: no metastasis, micrometastasis, and overt metastasis. We then performed microarray analysis on microdissected primary tumor cells and identified gene expression profiles associated with graded nodal tumor burden using a correlation-based selection algorithm coupled with cross-validation analysis. Hierarchical clustering showed the regrouping of tumor specimens; the classification inference was assessed with Fisher's exact test. We verified data for certain genes by using another independent assay. RESULTS: The 15 specimens clustered into 3 groups: cluster A predominated in specimens with overt nodal metastasis; cluster B had more specimens with nodal micrometastases; and cluster C included only specimens without nodal metastases. Cluster assignment was based on a validated 75-gene discriminatory subset. Notably, genes not previously associated with positive non-small cell lung carcinoma lymph node status were encountered in the profiling analysis. CONCLUSIONS: Microdissection, combined with microarray analysis, is a potentially powerful method to characterize the molecular profile of tumor cells. The 75-gene expression profiles representative of clusters A and B may define genotypes prone to metastasize. Overall, the 3 groups of tumor specimens clustered separately, suggesting that this approach may identify graded metastatic propensity. Further, genes singled out in clustering may yield insights into underlying metastatic mechanisms and may represent new therapeutic targets.

Carcinoma, Non-Small-Cell Lung↗
PubMed2004

Return to work after thoracic surgery: an overlooked outcome measure in quality-of-life studies.

In the literature on thoracic surgery, return to work has received little attention in QOL investigations. At present, it is difficult to appreciate clinically meaningful trends in return to work after thoracic surgery, even within a specialized area, such as lung cancer resection. It is evident, however, that return to work is not a simple variable, easily measured; rather, it is a complex construct that is influenced by a multitude of personal and societal factors. Focusing only on disease-related or treatment-related symptoms renders QOL studies limited in scope and perhaps in usefulness. Return to work is not a trivial component of global postsurgical QOL; it should be recognized as a major factor. Patients have indicated that maintaining return-to-work ability is as highly valued as their overall health. Surgical societies should design, validate, and implement a simple data collection instrument to characterize better return to work after thoracic surgery.

Employment↗
PubMed2004

Gene expression profiling identifies matriptase overexpression in malignant mesothelioma.

STUDY OBJECTIVE: We investigated the gene expression profiles of malignant pleural mesothelioma (MPM) specimens to identify novel genes that are potentially involved in the oncogenic transformation of human pleural cells. DESIGN: Complementary DNA (cDNA) microarray transcriptional profiling studies of 10 MPM cell lines and 4 MPM primary tumor specimens were performed using hierarchic clustering. To confirm microarray data, we used real-time polymerase chain reaction and immunoblotting. RESULTS: Cluster analysis differentiated among epithelial (E), sarcomatoid, and biphasic MPM variants. Expression profiling identified common overexpressed or underexpressed genes in MPM. Notably, matriptase messenger RNA was found to be overexpressed by 826-fold in E MPM, with protein expression subsequently confirmed by immunoblot analysis. This recently characterized trypsin-like serine protease has been implicated in tumor invasion and metastasis of E-derived cancers, but has not been described until now in MPM. We also identified other novel genes, such as insulin-like growth factor binding protein 5 and a cDNA clone similar to proteolipid MAL2. CONCLUSIONS: Thus, further large-scale profiling of MPM may elucidate previously unrecognized molecular mechanisms by identifying novel genes that are involved in malignant transformation. Our study has now found matriptase to be one of these mesothelioma-associated genes, with potential pathogenic and therapeutic significance.

Cell Line, Tumor↗