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Biomedical subjects

George Triadafilopoulos

Publications and source records attributed to George Triadafilopoulos.

At least 19 recordsLinked to original sources
PubMed2007

A novel retrograde-viewing auxiliary imaging device (Third Eye Retroscope) improves the detection of simulated polyps in anatomic models of the colon.

BACKGROUND: Colonoscopy is the "gold standard" for colorectal polyp and cancer detection, but important lesions may be missed on the proximal aspect of haustral folds, rectal valves, or flexures. OBJECTIVE: Our purpose was to evaluate a prototype auxiliary imaging device that extends beyond the colonoscope's tip, providing a continuous retrograde view to detect lesions missed by the forward-viewing colonoscope. DESIGN: Three anatomic models of the colon were prepared with simulated polyps, 32% in obvious locations and 68% on the proximal aspect of folds. Six endoscopists examined each model with two methods. Method A used a standard video colonoscope. Method B involved an identical colonoscope with a retrograde-viewing auxiliary device positioned within its instrument channel. Order of testing was randomized and blinded. SETTING: Laboratory bench. MAIN OUTCOME MEASUREMENTS: Detection rates for simulated polyps. RESULTS: Of 78 "obvious" polyps, 69 (88%) and 70 (90%) were detected by methods A and B, respectively (P > .9). In contrast, of 162 polyps on proximal aspects of folds, 20 (12%) and 131 (81%) were detected by methods A and B, respectively (P < .00001). LIMITATIONS: Limitations resulted from (1) use of commercially available anatomic models in which haustral folds are less prominent and more rigid than in humans and (2) evaluation of a prototype device that had larger size and narrower angle of view than the planned production model and that was fixed in relation to the colonoscope. CONCLUSIONS: In simulated testing, a retrograde-viewing auxiliary imaging device used with a standard video colonoscope significantly improves detection rates of simulated polyps and promises to enhance the diagnostic yield of colonoscopy in humans.

Colonic Polyps↗
PubMed2006

Clinical, radiologic, and manometric characteristics of chronic intestinal dysmotility: the Stanford experience.

BACKGROUND AND AIMS: The clinical spectrum of chronic intestinal dysmotility (CID) is not well known. We determined the spectrum of motor abnormalities, underlying pathology, clinical course, and response to treatment of adults with CID at a tertiary referral center. METHODS: This was a descriptive retrospective analysis of a CID cohort conducted at a tertiary referral gastrointestinal (GI) motility center. A total of 113 referred patients underwent gastroduodenal manometry, other motility studies as appropriate, and radiologic and/or endoscopic assessment to exclude mechanical intestinal obstruction. RESULTS: Common symptoms included abdominal distention, abdominal pain, nausea, and constipation. The course was chronic with intermittent symptoms. Gastroduodenal manometry was abnormal in all patients; a pattern suggestive of a neuropathic process was the most common. Other GI motility studies showed delayed gastric, gallbladder, and colonic transit, nonspecific esophageal dysmotility, sphincter of Oddi hypertonicity, and poor rectal balloon sensation/expulsion. Treatment involved nutritional support, prokinetics, analgesics, antinausea agents, and laxatives, with variable response and high morbidity, multiple emergency admissions, need for nutritional support, and poor response to surgery. Nearly 40% of the patients underwent abdominal surgery. CONCLUSIONS: Patients with CID have a chronic course and high morbidity. Because any segment of the GI tract may be involved in CID, functional assessment of the entire GI tract is recommended. CID presents several unmet clinical needs even in tertiary centers with expertise.

Adolescent↗
PubMed2006

Interventional upper endoscopy: the adult perspective.

Advances in interventional endoscopic technology and techniques are paving the way for the increased application of minimally invasive methods to treat various upper gastrointestinal conditions, both benign and malignant. Through the description of enteral stenting for palliation of malignant obstruction, expanded techniques of enteral feeding tube placement, mucosectomy of early gastric cancer, and snare ampullectomy for benign ampullary lesions, this review focuses on recent progress in therapeutic endoscopy of the stomach and duodenum and highlights the importance of continued research and development.

Adult↗
PubMed2006

Celecoxib versus naproxen and diclofenac in osteoarthritis patients: SUCCESS-I Study.

PURPOSE: To evaluate the efficacy and upper gastrointestinal (UGI) safety of celecoxib, compared with nonspecific nonsteroidal anti-inflammatory drugs (NSAIDs), among patients with osteoarthritis. METHODS: A total of 13274 osteoarthritis patients from 39 countries were randomly assigned to double-blind treatment with either celecoxib 100 mg twice daily (BID), celecoxib 200 mg BID, or nonselective NSAID therapy (diclofenac 50 mg BID or naproxen 500 mg BID) for 12 weeks. Standard validated measures were used to assess osteoarthritis efficacy. Serious UGI events were evaluated by 2 blinded, independent, gastrointestinal events committees. RESULTS: Results from all primary efficacy assessments showed that both dosages of celecoxib were as effective as NSAIDs in treating osteoarthritis. Significantly more ulcer complications occurred within the nonselective NSAID group (0.8/100 patient-years) compared with the celecoxib group (0.1/100 patient-years) (odds ratio = 7.02; 95% confidence interval [CI], 1.46 to 33.80; P =.008). There were fewer ulcer complications in the celecoxib group compared with the NSAID group, both in patients taking concomitant aspirin and those not taking aspirin, but the difference reached statistical significance only in the latter comparison. The number of cardiovascular thromboembolic events was low and not statistically different between the groups (eg, myocardial infarction rates: celecoxib 10 events [0.55/100 patient-years] vs NSAIDs 1 event [0.11/100 patient-years], (P =.11), but the study was not powered to detect such differences. CONCLUSIONS: In the treatment of osteoarthritis, celecoxib is as effective as the nonspecific NSAIDs naproxen and diclofenac, but has significantly fewer serious upper gastrointestinal events.

Anti-Inflammatory Agents, Non-Steroidal↗
PubMed2006

Colorectal neoplasia in veterans is associated with Barrett's esophagus but not with proton-pump inhibitor or aspirin/NSAID use.

BACKGROUND: It has been suggested that Barrett's esophagus (BE) is associated with an increased risk of developing colorectal neoplasia, but this has not been reported consistently. AIM: To study whether BE is associated with an increased risk of colorectal neoplasia, and if it is, whether it is dependent on use of proton-pump inhibitors (PPIs) or aspirin and nonsteroidal anti-inflammatory drugs (NSAIDs). DESIGN: Case-control study. SETTING: Endoscopic database of the Palo Alto Veterans Affairs Health Care System. POPULATION: 268 veterans with BE were matched with 268 controls without BE. INTERVENTION: Controls had undergone upper GI endoscopy within 14 days of the corresponding case. Colonoscopy was performed within 6 months in cases and controls. MAIN OUTCOME MEASURE: Development of colorectal neoplasia. RESULTS: Colorectal neoplasia was present in 162 of 268 (60%) BE patients and in 105 of 268 (40%) controls (p < 0.001). The presence of BE (odds ratio [OR] 2.02: 95% CI [1.35, 3.04]), but also increasing age (OR 1.24 per decade: 95% CI [1.04, 1.48]) and alcohol use (OR 1.70: 95% CI [1.16, 2.50]) were associated with an increased risk of colorectal neoplasia in multivariable logistic regression analysis, whereas PPIs (OR 0.99: 95% CI [0.66, 1.48]) and aspirin/NSAIDs (OR 0.90: 95% CI [0.61, 1.33]) had no meaningful effect. LIMITATIONS: This was a retrospective study in mostly male veterans. CONCLUSIONS: Veterans with BE are at an increased risk of developing colorectal neoplasia. This association is independent from the use of PPIs or aspirin/NSAIDs.

Aged↗
PubMed2006

Gene expression profiling reveals stromal genes expressed in common between Barrett's esophagus and adenocarcinoma.

BACKGROUND & AIMS: Barrett's esophagus is a precursor of esophageal adenocarcinoma. DNA microarrays that enable a genome-wide assessment of gene expression enhance the identification of specific genes as well as gene expression patterns that are expressed by Barrett's esophagus and adenocarcinoma compared with normal tissues. Barrett's esophagus length has also been identified as a risk factor for progression to adenocarcinoma, but whether there are intrinsic biological differences between short-segment and long-segment Barrett's esophagus can be explored with microarrays. METHODS: Gene expression profiles for endoscopically obtained biopsy specimens of Barrett's esophagus or esophageal adenocarcinoma and associated normal esophagus and duodenum were identified for 17 patients using DNA microarrays. Unsupervised and supervised approaches for data analysis defined similarities and differences between the tissues as well as correlations with clinical phenotypes. RESULTS: Each tissue displays a unique expression profile that distinguishes it from others. Barrett's esophagus and esophageal adenocarcinoma express a unique set of stromal genes that is distinct from normal tissues but similar to other cancers. Adenocarcinoma also showed lower and higher expression for many genes compared with Barrett's esophagus. No difference in gene expression was found between short-segment and long-segment Barrett's esophagus. CONCLUSIONS: The genome-wide assessment provided by current DNA microarrays reveals many candidate genes and patterns not previously identified. Stromal gene expression in Barrett's esophagus and adenocarcinoma is similar, indicating that these changes precede malignant transformation.

Adenocarcinoma↗
PubMed2006

Potential relationship between gastroesophageal reflux disease and atrial arrhythmias.

A potential reduction in symptoms related to atrial fibrillation after treatment of gastroesophageal reflux disease symptoms with proton pump inhibitor therapy has been previously described. However, illustration of this relationship by combined 24-hour pH and ambulatory Holter monitoring has not been performed. We report 3 patients with symptoms of both palpitations and reflux who underwent simultaneous Holter and 24-hour ambulatory pH monitoring off of antireflux therapy. All of the patients reported a reduction in arrhythmia symptoms on proton pump inhibitor therapy. The findings from this preliminary series suggest a potential relationship between gastroesophageal reflux disease and atrial arrhythmias that might improve with antireflux therapy. Patients with documentation of both atrial arrhythmias and reflux should have a trial of aggressive acid suppressive therapy To further confirm this relationship, larger prospective studies are needed to assess whether maximal acid suppression improves arrhythmias.

Aged↗
PubMed2005

Endoscopic therapy for Barrett's esophagus.

With the increase in the rate of esophageal adenocarcinoma in the United States and the Western world matched with the high morbidity and mortality of esophagectomy, there is an increasing need for new and effective techniques to treat and prevent esophageal adenocarcinoma. A wide variety of endoscopic mucosal ablative techniques have been developed for early esophageal neoplasia. However, long-term control of neoplasic risk has not been demonstrated. Most studies show that specialized intestinal metaplasia may persist underneath neo-squamous mucosa, posing a risk for subsequent neoplastic progression. In this article we review current published literature on endoscopic therapies for the management of Barrett's esophagus.

Barrett Esophagus↗
PubMed2005

Endoscopic antireflux therapy: the Stretta procedure.

The Stretta procedure is safe and effective for the treatment of GERD. There are well-documented clinical trial data supporting its use, including a randomized sham-controlled study, single- and multi-center prospective trials, and community practice reports. The complication rate is within the acceptable range for therapeutic endoscopic procedures and less than the published complication rate for laparoscopic fundoplication. The durability of effect also is established beyond 2 years in several studies. Stretta should be added to the GERD management algorithm specifically for patients considering an antireflux surgical procedure but who are not accepting of the risks of surgery and anesthesia. These patients typically present with incomplete GERD control, despite optimal antisecretory drug therapy, or intolerance to medical therapy. Stretta should be considered only for patients who fit the anatomic inclusion criteria, whereas antireflux surgery should be reserved for those who do not. The decision to undergo antireflux surgery or Stretta must be based on the relative risks and benefits of each procedure. Although antireflux surgery provides better control of esophageal acid exposure than Stretta, the outcomes for GERD symptoms, quality of life, and reduction in PPI use are comparable. Stretta has a low risk of acute adverse events, has no reported cases of long-term dysphagia, and obviates general anesthesia and hospitalization, whereas antireflux surgery has a reported adverse event rate of approximately 2%, a considerable incidence of dysphagia, and requires general anesthesia and 1 to 2 days in the hospital. Another advantage of the Stretta procedure is that antireflux surgery still can be performed in the case of failures. In conclusion, the Stretta procedure offers a minimally invasive, safe, and effective alternative to antireflux surgery for those patients who have GERD who are controlled unsatisfactorily on antisecretory medications, who are considering surgery, and who meet the anatomic criteria that make the procedure technically feasible and safe.

Ambulatory Surgical Procedures↗