Search PubMed⌕ Search

Biomedical subjects

M B Orringer

Publications and source records attributed to M B Orringer.

At least 19 recordsLinked to original sources
PubMed2006

Genomic amplification of MET with boundaries within fragile site FRA7G and upregulation of MET pathways in esophageal adenocarcinoma.

Esophageal adenocarcinoma (EA) is characterized by a poor prognosis making the identification of clinically targetable proteins essential for improving patient outcome. We report the involvement of multiple alterations of the MET pathway in EA development and progression. Microarray analysis of Barrett's metaplasia, dysplasia, and EA revealed overexpression of the MET oncogene in EAs but only those with MET gene amplification. STS-amplification mapping revealed that the boundary of the MET amplicon in these EAs is defined by fragile site FRA7G. We also identified an amplicon at 11p13 that resulted in amplification and overexpression of CD44, a gene involved in MET autophosphorylation upon HGF stimulation. Tissue microarrays with phospho-MET-specific antibodies demonstrated a uniformly high abundance of MET activation in primary EA and cells metastatic to lymph nodes but to a lesser extent in a subset of metaplastic and dysplastic Barrett's samples. Increased expression of multiple genes in the MET pathway associated with invasive growth, for example, many MMPs and osteopontin, also was found in EAs. Treatment of EA-derived cell lines with geldanamycin, an inhibitor for tyrosine kinases including MET receptor kinase, reduced cell migration and induced EA cell apoptosis. The data indicate that upregulation of the MET pathway may contribute to the poor outcome of EA patients and that therapeutic agents targeting this pathway may help improve patient survival.

Adenocarcinoma↗
PubMed2001

Randomized trial of preoperative chemoradiation versus surgery alone in patients with locoregional esophageal carcinoma.

PURPOSE: A pilot study of 43 patients with potentially resectable esophageal carcinoma treated with an intensive regimen of preoperative chemoradiation with cisplatin, fluorouracil, and vinblastine before surgery showed a median survival of 29 months in comparison with the 12-month median survival of 100 historical controls treated with surgery alone at the same institution. We designed a randomized trial to compare survival for patients treated with this preoperative chemoradiation regimen versus surgery alone. MATERIALS AND METHODS: One hundred patients with esophageal carcinoma were randomized to receive either surgery alone (arm I) or preoperative chemoradiation (arm II) with cisplatin 20 mg/m2/d on days 1 through 5 and 17 through 21, fluorouracil 300 mg/m2/d on days 1 through 21, and vinblastine 1 mg/m2/d on days 1 through 4 and 17 through 20. Radiotherapy consisted of 1.5-Gy fractions twice daily, Monday through Friday over 21 days, to a total dose of 45 Gy. Transhiatal esophagectomy with a cervical esophagogastric anastomosis was performed on approximately day 42. RESULTS: At median follow-up of 8.2 years, there is no significant difference in survival between the treatment arms. Median survival is 17.6 months in arm I and 16.9 months in arm II. Survival at 3 years was 16% in arm I and 30% in arm II (P = .15). This study was statistically powered to detect a relatively large increase in median survival from 1 year to 2.2 years, with at least 80% power. CONCLUSION: This randomized trial of preoperative chemoradiation versus surgery alone for patients with potentially resectable esophageal carcinoma did not demonstrate a statistically significant survival difference.

Adenocarcinoma↗
PubMed2001

Esophagectomy for achalasia: patient selection and clinical experience.

BACKGROUND: In 1989, we predicted an increasing number of esophagectomies for megaesophagus and for recurrent symptoms after prior esophagomyotomy or balloon dilatation for achalasia. Patient selection in this group is challenging, as the potential operative morbidity of an esophagectomy must be weighed against the expected clinical outcome after a redo esophagomyotomy or alternative procedures designed to salvage the native esophagus. METHODS: The hospital records of 93 patients undergoing esophagectomy for achalasia during the past 20 years were reviewed retrospectively and the results of operation assessed using our prospectively established Esophageal Resection Database and follow-up information obtained through personal contact with the patients. RESULTS: Patient age averaged 51 years. Indications for esophagectomy included tortuous megaesophagus (64%), failure of prior myotomy (63%), and associated reflux stricture (7%). Ninety-four percent of the patients underwent a transhiatal esophagectomy. Stomach was used as the esophageal substitute in 91% cases. Intraoperative blood loss averaged 672 mL. Postoperative length of stay averaged 12.5 days. Major complications included anastomotic leak (10%), recurrent laryngeal nerve injury (5%), delayed mediastinal bleeding requiring thoracotomy (2%), and chylothorax (2%). There were 2 hospital deaths (2%) from respiratory insufficiency and sepsis. Follow-up has averaged 38 months. In all, 95% of patients eat well; nearly 50% have required an anastomotic dilatation; troublesome regurgitation has been rare; and 4% have refractory postvagotomy dumping. CONCLUSIONS: Esophagectomy, preferably through a transhiatal approach, is generally safe and effective therapy in selected patients with achalasia. Unique technical considerations include difficulty encircling the dilated cervical esophagus, deviation of the esophagus into the right chest, large aortic esophageal arteries, and adherence of the exposed esophageal submucosa to the adjacent aorta after prior myotomy.

Adolescent↗
PubMed2001

Transhiatal esophagectomy for treatment of benign and malignant esophageal disease.

Since our initial 1978 report, we have performed transhiatal esophagectomy (THE) in 1085 patients with intrathoracic esophageal disease: 285 (26%) benign lesions and 800 (74%) malignant lesions (4.5% upper, 22% middle, and 73.5% lower third/cardia). THE was possible in 97% of patients in whom it was attempted; reconstruction was performed at the same operation in all but six patients. The esophageal substitute was positioned in the original esophageal bed in 98%, stomach being used in 782 patients (96%) and colon in those with a prior gastric resection. Hospital mortality was 4%, with three deaths due to uncontrollable intraoperative hemorrhage. Major complications included anastomotic leak (13%), atelectasis/pneumonia prolonging hospitalization (2%), recurrent laryngeal nerve paralysis, chylothorax, and tracheal laceration (< 1% each). There were five reoperations for mediastinal bleeding within 24 hours of THE. Intraoperative blood loss averaged 689 ml. Altogether, 78% of the patients had no postoperative complications. Actuarial survival of the cancer patients mirrors that reported after transthoracic esophagectomy. Late functional results are good or excellent in 80%. Approximately 50% have required one or more anastomotic dilatations. With intensive preadmission pulmonary and physical conditioning, use of a side-to-side staple technique (which has reduced the cervical esophagogastric anastomotic leak rate to less than 3%), and postoperative epidural anesthesia, the need for an intensive care unit stay has been eliminated and the length of hospital stay was reduced to 7 days. We concluded that THE can be achieved in most patients requiring esophageal resection for benign and malignant disease and with greater safety and less morbidity than the traditional transthoracic approaches.

Anastomosis, Surgical↗
PubMed2000

Identification and characterization of a 19q12 amplicon in esophageal adenocarcinomas reveals cyclin E as the best candidate gene for this amplicon.

Genomic DNA amplification in tumors is frequently associated with an increased gene copy number of oncogenes or other cancer-related genes. We have used a two-dimensional whole-genome scanning technique to identify gene amplification events in esophageal adenocarcinomas. A multicopy genomic fragment from a tumor two-dimensional gel was cloned, and genomic amplification encompassing this fragment was confirmed by Southern blot analysis. The corresponding DNA sequence was matched by BLAST to a BAC contig, which allowed the use of electronic-PCR to localize this amplicon to 19q12. Sequence tagged site-amplification mapping, an approach recently implemented in our laboratory (Lin, L. et al., Cancer Res., 60: 1341-1347,2000), was used to characterize the amplicon. Genomic DNA from 65 esophageal and 11 gastric cardia adenocarcinomas were investigated for 19q12 amplification using quantitative PCR at 11 sequence tagged site markers neighboring the cloned fragment. The amplicon was narrowed from >8 cM to a minimal critical region spanning <0.8 cM, between D19S919 and D19S882. This region includes the cyclin E gene. Fourteen expressed sequence tags (ESTs) covering the minimal region were then assayed for potential gene overexpression using quantitative reverse transcription-PCR. Seven of the selected ESTs were found to be both amplified and overexpressed. Among these seven ESTs, cyclin E showed the highest frequency of gene amplification and overexpression in the tumors examined, which allowed us to finalize the core-amplified region to <300 kb. These results indicate that cyclin E is the likely target gene selected by the amplification event at 19q12. The fact that cyclin E overexpression was found only in the amplified tumors examined indicates that gene amplification underlies the cyclin E gene overexpression. Our study represents the first extensive analysis of the 19q12 amplicon, and is the first to physically map the core-amplified domain to a region of <300 kb that includes cyclin E. Amplification of 19q12 was found neither in the 28 esophageal squamous cancers nor in the 39 lung adenocarcinomas examined but was observed in 13.8% of esophageal and 9.1% of gastric cardia adenocarcinomas.

Adenocarcinoma↗
PubMed2000

A minimal critical region of the 8p22-23 amplicon in esophageal adenocarcinomas defined using sequence tagged site-amplification mapping and quantitative polymerase chain reaction includes the GATA-4 gene.

The incidence of esophageal adenocarcinomas has increased greatly over the past 20 years. The genetic alterations associated with this disease, however, remain largely unknown. We identified recently a novel amplicon at 8p22-23 in esophageal adenocarcinomas using the restriction landmark genomic scanning two-dimensional gel technique. Four known genes within or near this amplicon were initially characterized. The cathepsin B (CTSB) gene was found to be amplified in 13% of esophageal tumors. CTSB was shown previously to be overexpressed without amplification in many other human cancers. An approach termed sequence tagged site-amplification mapping has been implemented in the present study, allowing the 8p22-23 amplicon to be narrowed from 12 cM to a <2-cM minimal amplified area located between markers D8S552 and D8S1759. The CTSB gene maps within this region. To identify other cancer-related candidate genes in this region, a positional candidate gene approach was subsequently applied to characterize this minimal critical region. An expressed sequence tag (EST), which was included in the minimal critical region, demonstrated both amplification and overexpression. This EST and the extended sequence from the EST were determined to be a novel sequence in the 3' untranslated region of the human GATA-4 gene. GATA-4, a member of a zinc finger transcription factor family, was confirmed to be amplified and overexpressed in esophageal adenocarcinomas and was localized within <0.5 kb from CTSB. Furthermore, amplification of 8p22-23 was detected in one of eight gastric cardia adenocarcinomas but was not observed in either human lung adenocarcinomas (n = 39) or in esophageal squamous cell carcinomas (n = 24). The relatively high frequency of the 8p22-23 amplification in esophageal (13.6%) and gastric cardia (12.5%) adenocarcinomas may indicate a specificity of this amplicon for tumors of gastroesophageal origin.

Adenocarcinoma↗
PubMed2000

Content of thoracic residency training and its relevance to the practice of medicine.

BACKGROUND: The Thoracic Surgery Directors Association (TSDA) curriculum book provides learning objectives for a thoracic surgery residency. Our purpose was to evaluate the relevance of these objectives through feedback from recent graduates. METHODS: Graduates of multiple TSDA programs were mailed a 50-item questionnaire. Survey items were objectives from the TSDA curriculum book representing six areas of thoracic surgery. Graduates rated each objective for adequacy of instruction and relevance to their current practice on Likert-type scales. RESULTS: Two hundred twenty-eight surveys were included in the analysis. Despite excellent operating room education, graduates across subspecialty lines reported the need for improved education in "nonoperative" subjects. Graduates practicing cardiac surgery reported little relevance of their general thoracic educational experience. Conversely, graduates practicing general thoracic surgery expressed the need for more/better educational experiences in thoracic oncology and esophageal surgery. CONCLUSIONS: Contemporary thoracic surgical education can be improved. A strong need for improvement exists in the teaching of "nonoperative" subjects. As graduates elect careers in thoracic subspecialties, a need exists to align thoracic surgery educational experiences with ultimate career goals of residents.

Curriculum↗
PubMed2000

Eliminating the cervical esophagogastric anastomotic leak with a side-to-side stapled anastomosis.

BACKGROUND: Although the acute postoperative complications of a cervical esophagogastric anastomosis are less than those with an intrathoracic esophageal anastomosis, the long-term sequelae of a cervical anastomotic leak are not as minor as initially reported. Nearly 50% of cervical anastomotic leaks result in an anastomotic stricture, and the subsequent need for chronic dilatations negates the merits of an operation intended to restore comfortable swallowing. OBJECTIVE: This study was undertaken to determine whether construction of a side-to-side stapled cervical esophagogastric anastomosis after transhiatal esophagectomy could reliably eliminate the majority of anastomotic leaks. METHODS: In 114 consecutive patients undergoing transhiatal esophagectomy, a functional side-to-side cervical esophagogastric anastomosis was constructed with the Auto Suture Endo-GIA II stapler (United States Surgical Corporation, Auto Suture Company Division, Norwalk, Conn) applied directly through the cervical wound. This side-to-side stapled anastomosis has 3 rows of staples. Early postoperative anastomotic morbidity, subsequent need for anastomotic dilatations, and patient satisfaction with swallowing were evaluated. RESULTS: Before the side-to-side stapled anastomosis, the incidence of cervical esophagogastric anastomosis leak in over 1000 patients undergoing transhiatal esophagectomy having a manually sewn anastomosis varied from 10% to 15%. Among the 111 survivors of transhiatal esophagectomy and a side-to-side stapled anastomosis, there were 3 (2.7%) clinically significant anastomotic leaks. This lowered incidence of leaks has contributed to reduction in the average length of stay after an uncomplicated transhiatal esophagectomy to 7 days and has provided more comfortable swallowing, ease of subsequent esophageal dilatations, and greater patient satisfaction. CONCLUSIONS: Construction of the cervical esophagogastric anastomosis with a side-to-side stapled anastomosis greatly reduces the frequency of anastomotic leaks and later strictures. The side-to-side stapled anastomosis is a major technical advance in the progression of refinements of transhiatal esophagectomy and a cervical esophagogastric anastomosis.

Aged↗
PubMed2000

Thoracic surgery training at the University of Michigan.

The process of thoracic surgery resident education is and always has been taken very seriously at the University of Michigan, where it is regarded as a key mission of the faculty. More attention is paid to the details of providing a supportive educational environment using established principles of education, curriculum planning, evaluation, and feedback. Resident education is the order of business today and, although challenged by the demands of managed care and cost containment, it remains among the most important priorities at the University of Michigan.

History, 20th Century↗
PubMed1999

Induction of glutathione s-transferase-pi in Barrett's metaplasia and Barrett's adenocarcinoma cell lines.

Barrett's metaplasia consists of columnar epithelium that replaces the normal esophageal mucosa in patients with chronic gastroesophageal reflux. Because intestinal-type Barrett's metaplasia is the major risk factor for adenocarcinoma development, understanding the mechanisms that predispose the esophageal mucosa to malignant degeneration is clinically important. Glutathione s-transferase (GST)-pi belongs to a class of protective enzymes whose activity has been shown to be much lower in Barrett's metaplasia than in the normal esophagus, where this form of GST is predominant. In the studies described here, using immunocytochemical analysis, we observed higher levels of cytoplasmic GST-pi protein in normal esophageal mucosa than in Barrett's metaplasia. Using northern blot analysis, we also observed lower GST-pi mRNA levels in Barrett's metaplasia than in normal esophagus or adenocarcinomas from the same patients. Using as model systems three Barrett's adenocarcinoma cell lines and short-term organ culture of freshly resected normal esophagus and Barrett's metaplasia, dose-dependent induction of GST-pi mRNA was observed by using butylated hydroxyanisole and dexamethasone. GST-pi mRNA in Barrett's metaplasia was induced up to 2.5-fold with 60 microM butylated hydroxyanisole and nearly fivefold with 320 nM dexamethasone after 24 h. These studies demonstrate the ability to induce protective GST-pi in Barrett's metaplasia and may suggest a mechanism for future chemoprevention studies in patients with this type of epithelium, which is at high risk for malignant degeneration.

Adenocarcinoma↗
PubMed1999

Identification of intestinal-type Barrett's metaplasia by using the intestine-specific protein villin and esophageal brush cytology.

Villin is an actin-binding cytoskeletal protein required for brush-border formation in the normal small intestinal and renal proximal tubule epithelium. Villin is a marker of cell differentiation in small intestinal and renal cell lineages, and recent studies have shown villin to be highly expressed in 100% of intestinal-type Barrett's metaplasias. This epithelium is the single greatest risk factor for developing esophageal adenocarcinoma and arises when the normal esophageal squamous epithelium is replaced by a small intestine-like columnar epithelium after damage by chronic gastroesophageal reflux. In intestinal-type Barrett's metaplasia, the villin protein exhibits a highly characteristic staining pattern in which strong apical, brush-border staining of columnar epithelial cells is observed. In this study, the ability to identify intestinal metaplastic cells by using this distinct villin staining pattern was examined in endoscopic esophageal brushings from patients with confirmed Barrett's metaplasia. Esophageal brushings from 81% (17 of 21) of patients with Barrett's metaplasia demonstrated individual columnar cells with the characteristic villin staining pattern, whereas all normal esophageal squamous cells, blood cells, and gastric columnar cells were negative for villin expression. Northern blot analysis demonstrated villin mRNA expression in Barrett's metaplasia but not in the normal squamous esophagus or gastric mucosa from the same patients. The combined use of villin immunohistochemical analysis and esophageal brush cytology may provide a simple and effective method of detecting intestinal-type Barrett's metaplasia in patients at higher risk for developing this epithelium, such as those experiencing chronic gastroesophageal reflux symptoms.

Barrett Esophagus↗
PubMed1999

As originally published in 1992: Anterior mediastinal tracheostomy with and without cervical exenteration. Updated in 1998.

Anterior mediastinal tracheostomy (AMT) facilitates resection of stomal recurrences after laryngectomy for carcinoma and tumors involving the cervicothoracic trachea and esophagus. Erosion of the innominate artery has been reported as a frequent major complication of AMT, and routine prophylactic division of the innominate artery with AMT has even been advised. Forty-four patients underwent AMT, 10 as an isolated procedure (for stomal recurrence, laryngeal carcinoma, or benign stenosis after laryngectomy) and 34 with concomitant cervical exenteration (laryngopharyngoesophagectomy) for laryngeal, thyroid, or cervicothoracic esophageal malignancies. Transposition of the remaining tracheal stump beneath and to the right of the innominate artery to eliminate tension on the vessel was carried out in 14 patients (32%). Postoperatively, anastomotic leaks complicated nine of 31 pharyngogastric anastomoses. Iatrogenic hypoparathyroidism occurred in 10 patients. All six hospital deaths (14%) occurred in patients undergoing AMT with cervical exenteration, not isolated AMT. There was only one instance of innominate artery erosion. Survival was related to the pathology for which AMT was performed. Anterior mediastinal tracheostomy is a valuable adjunct in the treatment of select patients with malignancies of the cervicothoracic trachea and esophagus, and with attention to operative detail, innominate artery erosion should rarely, if ever, complicate the operation. Prophylactic division of the innominate artery with AMT is unnecessary.

Esophageal Neoplasms↗
PubMed1999

Epidural abscess: a delayed complication of esophageal stenting for benign stricture.

A case of anterior cervical epidural abscess associated with perforation of an endoscopically placed esophageal stent is presented. Although delayed esophageal perforation is a known complication of endoscopic stenting, no cases presenting with epidural abscess have yet been reported. The increasing application of endoscopic stenting for benign esophageal strictures provides greater opportunity for this type of delayed complication.

Abscess↗
PubMed1999

Differential expression of Hsp27 in normal oesophagus, Barrett's metaplasia and oesophageal adenocarcinomas.

The protein expression patterns of normal, metaplastic and malignant oesophageal tissues were analysed by two-dimensional polyacrylamide gel electrophoresis (2D-PAGE) to identify changes associated with Barrett's metaplasia and transformation to oesophageal adenocarcinoma. Heat-shock protein 27 (Hsp27), a small heat-shock protein which is protective against cytotoxic stresses, was abundant in normal oesophagus. However, Hsp27 expression was markedly lower in Barrett's metaplasia and oesophageal adenocarcinomas. This was confirmed by immunohistochemical analysis. Hsp27 protein was most highly expressed in the upper layers of squamous epithelium and exhibited a pattern of expression that corresponded with the degree of squamous maturation. Northern and Southern analysis demonstrated Hsp27 to be regulated at the level of mRNA transcription or abundance. Normal oesophageal tissues were examined for gender differences in Hsp27 expression. Women expressed fourfold higher levels of Hsp27 mRNA, however, this difference was not appreciable in protein expression. Hsp27 protein was inducible by heat shock in Barrett's adenocarcinoma cell lines and an immortalized oesophageal epithelial cell line (HET-1A), but not by oestradiol. These results demonstrate abundant constitutive expression of the stress-response protein Hsp27 in the normal oesophagus, and suggest that low-level expression in Barrett's metaplasia may be one factor which may influence susceptibility to oesophageal adenocarcinoma development.

Adenocarcinoma↗
PubMed1999

Cytochromes P450 are expressed in proliferating cells in Barrett's metaplasia.

The expression of cytochromes P450 (CYP) in Barrett's esophagus and esophageal squamous mucosa was investigated. Esophagectomy specimens from 23 patients were examined for CYP expression of CYP1A2, CYP3A4, CYP2C9/10, and CYP2E1 by immunohistochemical analysis, and the expression of CYP1A1, CYP3A4, CYP1B1, CYP2E1, and CYP2C9/10 in these tissues was further confirmed by reverse transcription polymerase chain reaction. Immunohistochemical analysis of esophageal squamous mucosa (n = 12) showed expression of CYP1A2, CYP3A4, CYP2E1, and CYP2C9/10 proteins, but it was noted that cells within the basal proliferative zone did not express CYPs. Immunohistochemical analysis of Barrett's esophagus (n = 13) showed expression of CYP1A2, CYP3A4, CYP2E1, and CYP2C9/10 that was prominent in the basal glandular regions, which are areas containing a high percentage of actively proliferating cells. Immunohistochemical staining for both proliferating cell nuclear antigen and the CYPs further supported the colocalization of CYP expression to areas of active cell proliferation in Barrett's esophagus, whereas in the esophageal squamous epithelium, CYP expression is limited to cells that are not proliferating. RT-PCR with amplification product sequence analysis confirmed CYP1A1, CYP3A4, CYP1B1, CYP2E1, and CYP2C9/10 mRNA expression in Barrett's esophagus. These data suggest that the potential ability of cells in Barrett's esophagus to both activate carcinogens and proliferate may be important risk factors affecting carcinogenesis in this metaplastic tissue.

Barrett Esophagus↗