Anil B. Nagar

Yale University, New Haven, CT, United States

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Publications (9)53.59 Total impact

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    ABSTRACT: Colonoscopy surveillance interval data longer than 5 years are limited. We examined adenoma yield to identify factors that predict appropriate intervals for postpolypectomy surveillance greater than 5 years, including risk of advanced adenoma recurrence. We identified patients with and without adenomas on an index colonoscopy who returned at 5 to 10 years for a follow-up colonoscopy. Multivariate logistic regression was used to identify variables that predict finding an adenoma on follow-up colonoscopy. Three hundred ninety-nine patients were identified with a follow-up colonoscopy at an interval of >5 years. Irrespective of surveillance interval, adenoma incidence occurred in 116 patients (29.1%) with 25 (6%) having advanced adenomas. Patients with nonadvanced adenomas on index colonoscopy had a similar risk of advanced adenoma on follow-up colonoscopy at 5 years versus 6 to 10 years, 5% versus 6.2% (P=0.39). The risk of advanced adenoma at 5 and 6 to 10 years in patients with a negative index colonoscopy was 7% versus 3.6% (P=0.15). Patients with an advanced adenoma at index colonoscopy had the highest rate of advanced adenoma detection at 5 years at 26%. Proximal polyp location (odds ratio 12.4, confidence interval 2.7-56.7) predicted advanced adenoma occurrence at 5 years. Postpolypectomy colonoscopy intervals can be extended beyond 5 years in patients with nonadvanced adenomas. Our findings also support a rescreening interval of 5 to 10 years in patients with a negative index colonoscopy. Patients with an index advanced adenoma are at highest risk for recurrent advanced adenoma and should have repeat colonoscopy before a 5 years interval.
    Journal of clinical gastroenterology 09/2010; 44(8):e162-6. · 2.21 Impact Factor
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    ABSTRACT: Acute pancreatitis is a painful inflammatory disorder known to occur in children. Recent reports, primarily on the basis of adult data, have suggested an increasing incidence. However, pediatric studies are limited. The study was performed to examine the frequency of acute pancreatitis in a pediatric population from 1994 to 2007 and to characterize etiologies by age subsets. In this retrospective study, cases of pancreatitis were identified by ICD-9 codes and subjected to inclusion criteria. Two hundred and seventy-one cases of pancreatitis met inclusion criteria. Mean age of the subjects was 13.1 +/- 5.6 years. The recurrence rate was 15.3%. Biliary disease was the most common etiology (32.6%). Acute pancreatitis cases evaluated at a single tertiary care center increased 53% between 1995 to 2000 and 2001 to 2006 (P < 0.02). However, when cases were normalized by all annual pediatric emergency department visits for all medical reasons, the increase was reduced to 22% and lost statistical significance (P = 0.16). The rise was not associated with a change in etiologies or body mass index (BMI). This is the first report demonstrating that an increase in pediatric pancreatitis may in part be due to growing referrals to tertiary care centers. The data on etiologies, particularly with regard to differing ages, may be helpful in managing children who present with acute pancreatitis.
    Journal of pediatric gastroenterology and nutrition 06/2009; 49(3):316-22. · 2.18 Impact Factor
  • Anil B Nagar, Fred Gorelick
    Gut 12/2008; 57(11):1492-3. · 10.73 Impact Factor
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    ABSTRACT: Ethanol abuse can lead to hepatic steatosis and evolve into cirrhosis and hepatocellular carcinoma. Pigment epithelium-derived factor (PEDF) is a multifunctional secreted glycoprotein that is expressed by hepatocytes. Proteomic, experimental, and clinical studies implicate PEDF's role in lipid regulation. Because matrix metalloproteinase (MMP)-2/9 activity regulates PEDF levels, we investigated whether PEDF degradation by MMPs has a permissive role in ethanol-induced hepatic steatosis. PEDF levels were examined in liver biopsy specimens from patients with ethanol-induced steatosis. Hepatic PEDF levels and MMP activity were assessed in 2 animal models of ethanol feeding (rats on an alcohol-containing liquid diet and mice given intragastric infusion of ethanol). The consequences of PEDF depletion in the liver were examined in PEDF-null mice. Liver biopsy samples from patients with ethanol-induced steatosis had reduced PEDF levels, compared with normal liver samples. Ethanol-fed animals had histologic steatosis and increased liver triglyceride content (P< .05), as well as reduced levels of hepatic PEDF and increased MMP-2/9 activity. Ethanol-exposed hepatic lysates degraded PEDF in a MMP-2/9-dependent manner, and liver sections demonstrated abundant MMP-2/9 activity in situ. Addition of recombinant PEDF to PEDF-null hepatocytes, reduced their triglyceride content. Ethanol exposure leads to marked loss of hepatic PEDF in human livers and in 2 animal models of ethanol feeding. Loss of PEDF contributes to the accumulation of lipids in ethanol-induced hepatic steatosis.
    Gastroenterology 10/2008; 136(1):331-340.e2. · 12.82 Impact Factor
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    ABSTRACT: Bouveret's syndrome is a rare condition of gastric outlet obstruction resulting from the migration of a gallstone through a choledochoduodenal fistula. Due to the large size of these stones and the difficult location in which they become impacted, endoscopic treatment is unsuccessful and most patients require surgery. We report the case of an elderly male who presented with nausea and hematemesis, and was found on CT scan and endoscopy to have an obstructing gallstone in his duodenal bulb. After several endoscopic sessions and the use of multiple instruments including a Holmium: YAG laser and electrohydraulic lithotripter, fragmentation and endoscopic removal of the stone were successful. We believe this to be the first case of Bouveret's syndrome successfully treated by endoscopy alone in the United States. We describe the difficulties encountered which necessitated varied and innovative therapeutic techniques.
    Diagnostic and Therapeutic Endoscopy 02/2008; 2008:471512.
  • Gastroenterology 01/2008; 134(4). · 12.82 Impact Factor
  • Gastroenterology 01/2008; 134(4). · 12.82 Impact Factor
  • Anil B Nagar
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    ABSTRACT: Isolated ulcers of the large intestine are not associated with an underlying colitis and may be an incidental finding on screening colonoscopy or present with abdominal pain, hematochezia, chronic gastrointestinal bleeding, and rarely, perforation. A common cause of isolated colonic ulcers is the use of nonsteroidal anti-inflammatory drugs (NSAIDs), with ulcers in the cecum and right colon. Isolated rectal ulcers are caused by ischemia, solitary rectal ulcer syndrome (SRUS), radiation, or fecal impaction. Stercoral ulceration and nonspecific ulcers of the colon are rare but can cause colonic perforation. Infectious causes include tuberculosis and amebiasis. Histology is important to rule out malignancy but is not helpful for diagnosis except in SRUS and certain infections. The approach to isolated colonic ulceration includes biopsy of the ulcer and surrounding tissue, cessation of any NSAIDs, management of constipation, and recognition of the patient with SRUS. Inflammatory bowel disease should be ruled out in appropriate patients.
    Current Gastroenterology Reports 11/2007; 9(5):422-8.
  • Timothy Wong, Jianmin Tian, Anil B. Nagar
    Gastrointestinal Endoscopy - GASTROINTEST ENDOSCOP. 01/2007; 65(5).