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Biomedical subjects

Christopher S Huang

Publications and source records attributed to Christopher S Huang.

12 recordsLinked to original sources
PubMed2006

Comparison of microsatellite instability, CpG island methylation phenotype, BRAF and KRAS status in serrated polyps and traditional adenomas indicates separate pathways to distinct colorectal carcinoma end points.

The aim of this study was to compare BRAF and KRAS, CpG island methylator phenotype (CIMP), and microsatellite instability (MSI) status in each of the histologic categories, including end-point carcinomas with residual adenoma, of the serrated polyp neoplasia pathway and the traditional (nonserrated) adenoma-carcinoma sequence. Deoxyribonucleic acid (DNA) was extracted from the selected samples and assayed for BRAF, KRAS2 codon12, 13, CIMP using markers hMLH1, MGMT, MINT1, MINT2, p16, and MSI using an assay for BAT25 and BAT26. A BRAF mutation was present in 82% of serrated carcinomas (SCas), 62% of serrated adenomas (SAs), 83% of serrated polyps with abnormal proliferation (SPAPs-syn. sessile serrated adenoma [SSA]), 76% of microvesicular serrated polyps (MVSPs), and was not found in any of the histologic categories of the traditional adenoma-carcinoma sequence. KRAS2 mutations were found in 43% of the goblet cell serrated polyp (GCSP) category, 13% of MVSPs, 7% of SPAPs, and 24% of SAs; in 26% of large traditional adenoma (lTAs) compared with small traditional adenomas (sTAs) (0/30; P<0.005) and in 37.3% of traditional carcinomas (TCa). CIMP-H (>1 marker positive) was significantly more frequent in SPAP, SA, and SCa compared with MVSP (P<0.05); CIMP-H was present in 10% of sTAs but was found more frequently in lTA (44.4%; OR 7.2; P=0.007) and TCa (38.9%; OR 5.8; P=0.007). Higher CIMP levels (4 or more markers positive) were significantly more frequent in advanced categories of the serrated pathway (SAs [31%] and SCas [30%]) compared with lTAs [0%] and TCAs [3.4%] (OR 12.2; P=0.02). MSI-H was identified only in the adenocarcinoma component of SCas (9/11) or in the contiguous SAs (3/7). The findings indicate that a BRAF mutation is a specific marker for a serrated polyp pathway that has its origin in a hyperplastic polyp (MVSP) and a potential end point as MSI carcinoma. CIMP-High (CIMP-H) develops early in this sequence and MSI-H develops late. The data provided a less complete picture of a second serrated pathway, identified by a KRAS2 mutation in SAs, but showed that the progressive stages of both iterations of the serrated neoplasia pathway are separate and distinct from those of the traditional adenoma-carcinoma sequence.

Adenocarcinoma↗
PubMed2005

Colorectal cancer screening in average risk individuals.

Colorectal cancer is the third leading type of cancer, and the second leading cause of cancer-related death in the United States. Prevention of colorectal cancer should be achievable by screening programs that detect adenomas in asymptomatic patients and lead to their removal. In this manuscript, we review the major screening modalities, the advantages and disadvantages of each approach, the data supporting their use, and various issues affecting the implementation of each test. Screening guidelines will be reviewed, and future techniques for colorectal cancer screening examined.

Adenoma↗
PubMed2005

Treatment of Biliary Problems in Inflammatory Bowel Disease.

The most common biliary problem in patients with inflammatory bowel disease is primary sclerosing cholangitis (PSC). The treatment of this disease is multifaceted and frequently requires a multidisciplinary approach involving internists, nutritionists, gastroenterologists, and surgeons. Unfortunately, other than liver transplantation, no therapy that is currently available has been proven to alter the natural history of PSC or prolong survival. Ursodeoxycholic acid is currently the most promising pharmacologic treatment option for slowing disease progression and should be used in higher than usual doses (20 to 30 mg/kg/d). Treatment of symptoms due to cholestasis, such as pruritis and steatorrhea, is an important aspect of the medical care of patients with PSC. Our preferred treatment of pruritis due to cholestasis is with bile acid binding exchange resins such as cholestyramine or colestipol (which is generally better tolerated than cholestyramine). Endoscopic therapy should be reserved for patients with obstructive jaundice, cholangitis, or symptomatic dominant biliary strictures. We recommend dilation of dominant strictures with graduated or balloon dilators followed by temporary stenting if the postdilation cholangiographic appearance is not improved or adequate biliary drainage cannot be assured. There is indirect evidence that the combination of ursodeoxycholic acid and endoscopic therapy to maintain biliary patency may improve transplant-free survival in patients with PSC, although this remains to be proven. Liver transplantation remains the only effective treatment of advanced PSC, and should be considered in patients with complications of cirrhosis or intractable pruritis or fatigue.

Journal Article↗
PubMed2005

Endoscopy in the bariatric surgical patient.

Endoscopy in the bariatric surgical patient presents a new challenge for gastroenterologists, one that will be encountered with increasing frequency as the performance of bariatric surgery increases. To ensure a safe, successful, and useful endoscopy, it is important to be familiar with the expected postsurgical anatomy and endoscopic appearance after the various bariatric operations and common complications that can arise.

Bariatrics↗
PubMed2003

Endoscopic findings and their clinical correlations in patients with symptoms after gastric bypass surgery.

BACKGROUND: The aim of this study was to describe the endoscopic findings in patients with upper GI symptoms after Roux-en-Y gastric bypass surgery and to correlate clinical features with endoscopic findings. METHODS: Patients with symptoms after Roux-en-Y gastric bypass referred for endoscopy were studied. Endoscopy was performed in standard fashion with a 9.8-mm diameter endoscope. RESULTS: Forty-nine patients underwent a total of 69 upper endoscopy procedures between January 2001 and February 2003. The most common endoscopic findings were the following: normal post-surgical anatomy (21 patients, 43%), marginal ulcer (13 patients, 27%), stomal stenosis (9 patients [19%], including 5 with a concomitant marginal ulcer), and staple-line dehiscence (8 patients [16%], including one with a marginal ulcer). Abdominal pain was the most common symptom (26 patients, 53%) and was more frequent among patients with a normal endoscopy compared with those with an abnormal endoscopy (p=0.04). Stomal stenosis was present in 39% of patients with nausea, vomiting, or dysphagia; it was not present in any patient without these symptoms (p=0.001). Fifteen percent of procedures performed within the first 6 postoperative months were normal, compared with 53% of those performed beyond 6 months (p=0.02). There was no complication of endoscopy. CONCLUSIONS: Among patients with symptoms after Roux-en-Y gastric bypass presenting for endoscopy, normal post-surgical anatomy was the most common finding. Marginal ulcer was the most common abnormality. Presentation with abdominal pain and performance of endoscopy beyond the 6th post-operative month were predictive of a normal endoscopy, and lack of nausea, vomiting, and dysphagia predicted the absence of stomal stenosis.

Abdominal Pain↗
PubMed2003

Nonvariceal upper gastrointestinal bleeding.

Nonvariceal UGI bleeding is one of the most common emergencies that gastroenterologists encounter, and continues to be a significant cause of morbidity and mortality. The keys to management are rapid resuscitation and stabilization; appropriate triage based on pre-endoscopic risk factors; early endoscopy to achieve prompt diagnosis and implement hemostatic therapy to high-risk lesions; and aggressive antisecretory therapy (in the case of peptic ulcer bleeding) to reduce the risk of continued or recurrent bleeding.

Algorithms↗