Distal Loop Research Articles

Mechanistic insights into the effect of phosphorylation on Ras conformational dynamics and its interactions with cell signaling proteins

Ras undergoes interconversion between the active GTP-bound state and the inactive GDP-bound state. This GTPase cycle, which controls the activities of Ras, is accelerated by Ras GTPase-activating proteins (GAPs) and guanine nucleotide exchange factors (SOS). Oncogenic Ras mutations could affect the GTPase cycle and impair Ras functions. Additionally, Src-induced K-Ras Y32/64 dual phosphorylation has been reported to disrupt GTPase cycle and hinder Ras downstream signaling. However, the underlying mechanisms remain unclear. To address this, we performed molecular dynamics simulations (~30 μs in total) on unphosphorylated and phosphorylated K-Ras4B in GTP- and GDP-bound states, and on their complexes with GTPase cycle regulators (GAP and SOS) and the effector protein Raf. We found that K-Ras4B dual phosphorylation mainly alters the conformation at the nucleotide binding site and creates disorder at the catalytic site, resulting in the enlargement of GDP binding pocket and the retard of Ras-GTP intrinsic hydrolysis. We observed phosphorylation-induced shift in the distribution of Ras-GTP inactive-active sub-states and recognized potential druggable pockets in the phosphorylated Ras-GTP. Moreover, decreased catalytic competence or signal delivery abilities due to reduced binding affinities and/or distorted catalytic conformations of GAP, SOS and Raf were observed. In addition, the allosteric pathway from Ras/Raf interface to the distal Raf L4 loop was compromised by Ras phosphorylation. These results reveal the mechanisms by which phosphorylation influences the intrinsic or GAP/SOS catalyzed transformations between GTP- and GDP-bound states of Ras and its signal transduction to Raf. Our findings project Ras phosphorylation as a target for cancer drug discovery.

Pericecal Hernia

Background: Internal hernias involve prolapse of any viscus through normal or abnormal mesenteric or peritoneal aperture and constitute <1% of all cases of hernia. Pericecal hernia is one form of internal hernia rarely reported in the pediatric population. Clinical Description: We describe the case of a 10-year-old boy with underlying tetralogy of Fallot, who presented with third episode of severe abdominal pain, requiring hospital admission with tenderness in the umbilical and right iliac quadrants, voluntary guarding but no organomegaly or abdominal distension, and preserved bowel sounds. Management: Baseline investigations (complete blood count, C-reactive protein, erythrocyte sedimentation rate, blood culture sensitivity, and stool and urine microscopy) and serum amylase and lipase were normal. Ultrasound showed mesenteric lymphadenopathy but no pancreatitis or appendicitis. Computed tomography (CT) demonstrated circumferential wall thickening in distal ileum with clustering of distal ileal loops, posterior and lateral to the cecum, extending into right paracolic gutter, suggestive of pericecal hernia. Child received conservative management and improved. Definitive surgical reduction was deferred due to negative parental consent. Conclusion: To conclude, internal abdominal hernia is rare in children with nonspecific clinical presentation. CT should be considered when underlying etiology of acute abdomen is not found on the basis of history, examination, and baseline investigative workup. Early intervention helps in reducing the morbidity and mortality to great extent.

S2371 Endoscopic Vacuum Therapy (EVT) for the Successful Treatment of Duodenal Fistula

INTRODUCTION: Perforation is a devastating complication. The solution has always been surgical. At the Minneapolis, we have encountered a case of complicated duodenal ulcer which failed both surgical and radiology interventions. The EVT finally achieved the closure. CASE DESCRIPTION/METHODS: A 65 y/o veteran presented with persistent vomiting and weight loss. Initial CT revealed a large stomach and a duodenal wall thickening. EGD showed a large amount of bezoar, reflux esophagitis, and ulcerated duodenal stricture that only 6mm endoscope could pass. A 15 mm Axio stent was placed in the stricture. The patient’s symptoms improved and the stent was removed after 3 weeks. Two weeks later, the symptoms recurred. NPO and TPN were initiated. Repeat EGD revealed a pin point pylorus that could not be traversed. Liquid contrast was injected. A duodenal fistula between the duodenal bulb and sub-hepatic space was identified. A surgical procedure was then performed consisting of pylorus exclusion, gastro-jejunostomy (GJ), and sub-hepatic drain, Continuous bilious material via the sub-hepatic drain continued. The patient was unable to tolerate any oral intake. A PEG-J tube then was inserted by the Interventional radiology. Afterwards, the patient’s abdominal pain and drainage increased. Another EGD was performed. This time, a wide-open GJ was seen. The tube was found to pass through the suture line of the “excluded pylorus”. There were 2 additional disruptions at suture line. The PEG-J tube was repositioned into the GJ. The 3 open disruptions at the suture lines were cauterized using argon plasma and then closed using two 8mm and one 12mm Ovasco clips. Within a week, the percutaneous drain from the fistula decreased by 80%. But abdominal pain continued. A fifth EGD was performed to initiate EVT. A new PEG-J tube was inserted through the GJ into the duodenum loop. The distal tip loop string of the tube was secured onto the duodenal wall using 3 small endo-clips. High vacuum suction was applied to the J-port. Within a few days, all drainage from the fistula had ceased. A sixth EGD showed that 1 of the 3 Ovasco clips had fallen off so that standard 9mm endoscope could pass. The duodenal bulb was narrowed. The fistula resolved. The PEG-J was removed. DISCUSSION: EVT is a very effective treatment for perforation and fistula. The fundamental basis is to evacuate gastric, bile, and pancreatic secretions near the internal wound. This therapy should be considered as first-line rather than last resort.

S2909 Granulomatous Appendicitis: Idiopathic or Prospective Crohn’s Disease?

INTRODUCTION: Isolated granulomatous inflammation of the appendix is a rare entity, identified histologically in < 2% of specimens, and typed into idiopathic granulomatous appendicitis (GA) and appendiceal Crohn’s disease (CD). Less than 10% of GA cases develop CD. CASE DESCRIPTION/METHODS: A healthy 26-year-old male was advised to seek care for computed tomography (CT) suggesting acute appendicitis, ordered to assess dysuria and right testicular and abdominal pain of 1-month duration. CT measured a dilated appendix extending to the seminal vesicle, with fecolith and fat stranding. Vitals were stable, abdomen benign, and labs normal. During appendectomy, an inflamed appendix was seen adherent to the bladder. An uneventful post-op period was followed by discharge home. Despite interval recovery, readmission for pain, vomiting, and diarrhea occurred on POD 10. Tachycardia was noted without fever. Abdomen was distended and generally tender. There was leukocytosis. CT found thickened jejunum with proximal dilation and air-fluid-levels. Jejunitis and obstruction resolved with conservative care, but evidence of GA (granuloma with giant cell, negative AFB and GMS stains) on recent pathology prompted testing for a broadened differential. There was denial of travel, ill contacts, personal and family history of CD, but admittance to colonoscopy a decade prior with findings of proctitis. Blood, urine, and stool cultures, as well as C. difficile and O&P were negative. CD, tuberculosis, fungal, and Coccidioides serologies were negative. Ileocolonoscopy found post-op cecal changes. Random ileocolonic biopsies resulted normal mucosa. With clinical stabilization, discharge home was planned. During follow-up visit, the patient declared return to normalcy, and thus declined investigations for CD. DISCUSSION: Causes of GA include infectious, systemic, and local reactions, but often remains elusive, as does a uniform approach to diagnosis and management. Omitted tests limit confidence in diagnosing idiopathic GA, and uncertainty in proper follow-up delays diagnosis of related conditions. Despite idiopathic labeling, we remain vigilant to alternate causes. The patient at first lacked acute infectious features, but as Yersenia is linked to ¼ of cases, serologic testing would be ideal to exclude infection and support idiopathic nature. Sub-acuity lends support to interval appendectomy as a cause. Lastly, a remote history of proctitis, in concert with enteritis on readmit, may hint at chronicity, and begs close follow-up for CD.Figure 1.: Histology showing presence of non-caseating granulomas in a background of lymphocytic inflammation in the appendiceal wall (x10).Figure 2.: Histology showing a giant cell in a granuloma in the appendiceal wall (x10).Figure 3.: Computed tomography of the abdomen and pelvis with IV contrast showing diffuse circumferential thickening of multiple distal jejunal loops.

Our arteriovenous fistula experiences with grafts in hemodialysis patients

Aim: In patients whose life is dependent on hemodialysis, the most suitable vascular access routes are arteriovenous fistulas made with native vessels. However, in patients whose natural vessels are depleted, or not suitable, arteriovenous fistulas can be opened with artificial grafts. Our aim is to examine arteriovenous fistulas opened with synthetic grafts in hemodialysis patients who do not have native vascular access in the upper extremity and share our results.Methods: Patients who underwent opening of an arteriovenous fistula with a synthetic graft to the upper extremities in Adıyaman University Faculty of Medicine, Cardiovascular Surgery Clinic between December 2012 and December 2018 were examined in this retrospective cohort study. They were screened for age, gender, end-stage renal failure etiology, complications in vascular access site, postoperative follow-up, and duration of use. Primary and secondary patency rates were determined.Results: It was determined that synthetic grafts were used in 33 (15 males, 18 females) out of 436 arteriovenous fistulas (AVF) opened to 372 patients. The mean age was 59.2 (17) years. Left radiocephalic (RC) straight graft fistula was opened in 2 patients, left brachiocephalic (BC) straight graft fistula was opened in 12, left BC distal loop AVF in 13, right BC distal loop AVF in 1, left brachioaxillary (BA) distal loop AVF in 3 and right BA distal loop was used to open an AVF in 2 patients. Primary cumulative patency rates were as follows: 72% in the 3rd month, 65% in the 6th month, 42.24% in the 12th month. The secondary patency rates were 33.9% in the 60th month, 12% in the 60th month, 96.96% in the 12th and 24th months, 90.28% in the 36th and 48th months, 59.12% in the 60th month and 43.11% in the 72nd month.Conclusion: In chronic renal failure patients who do not have a natural vascular access routes or whose natural routes have been exhausted, AVFs that are opened to the upper extremities with a synthetic graft are suitable vascular access routes for long-term dialysis.

“Meckel’s Diverticulum” – A diagnostic bizarre of abdominal pain in adults

A 30-year-old male presented to the emergency room with complaints of periumbilical abdominal pain and vomiting. A contrast-enhanced computed tomography scan of the abdomen revealed subacute intestinal obstruction with dilated small bowel loops and associated bowel wall thickening of mid and distal ileal bowel loops. There was a fairly large small bowel diverticulum arising from the antimesenteric border of distal ileum. Findings were suggestive of small bowel diverticulitis or possibly focal enteritis. The patient was then immediately taken to the operating room for emergency laparotomy and was intra-operatively found to have a thickened Meckel’s diverticulitis with adjacent small bowel obstruction. Meckel’s diverticulectomy was performed in continuity with the adjacent inflamed small bowel. The patient had a stable post-operative course without any complications and was discharged within a week.

Development of extrinsic innervation in the abdominal intestines of human embryos.

Compared to the intrinsic enteric nervous system (ENS), development of the extrinsic ENS is poorly documented, even though its presence is easily detectable with histological techniques. We visualised its development in human embryos and foetuses of 4–9.5 weeks post‐fertilisation using Amira 3D‐reconstruction and Cinema 4D‐remodelling software. The extrinsic ENS originated from small, basophilic neural crest cells (NCCs) that migrated to the para‐aortic region and then continued ventrally to the pre‐aortic region, where they formed autonomic pre‐aortic plexuses. From here, nerve fibres extended along the ventral abdominal arteries and finally connected to the intrinsic system. Schwann cell precursors (SCPs), a subgroup of NCCs that migrate on nerve fibres, showed region‐specific differences in differentiation. SCPs developed into scattered chromaffin cells of the adrenal medulla dorsolateral to the coeliac artery (CA) and into more tightly packed chromaffin cells of the para‐aortic bodies ventrolateral to the inferior mesenteric artery (IMA), with reciprocal topographic gradients between both fates. The extrinsic ENS first extended along the CA and then along the superior mesenteric artery (SMA) and IMA 5 days later. Apart from the branch to the caecum, extrinsic nerves did not extend along SMA branches in the herniated parts of the midgut until the gut loops had returned in the abdominal cavity, suggesting a permissive role of the intraperitoneal environment. Accordingly, extrinsic innervation had not yet reached the distal (colonic) loop of the midgut at 9.5 weeks development. Based on intrinsic ENS‐dependent architectural remodelling of the gut layers, extrinsic innervation followed intrinsic innervation 3–4 Carnegie stages later.

Key Dynamic Residues in the Catalytic Activity of Human Cyclophilins Identified with a Dynamical Evolution Analysis

Cyclophilins belong to peptidyl‐prolyl isomerases (PPIases), a group of enzymes catalyzing the interconversion of the peptide bond preceding a proline between the cis and trans isomer. Of the 17 unique human cyclophilins, five closely related homologues (CypA‐E) were the focus of this project. These five isoforms function in a variety of environments, and participate in diverse subcellular processes, yet all have highly conserved sequences, very similar structures, and the same core catalytic function. As dynamics are known to couple protein function, looking into the conserved dynamics can provide insights into the catalysis of peptidyl‐prolyl isomerization by cyclophilins. Functional dynamics were compared using multiple statistical analyses, including Cartesian and dihedral principal component analysis (PCA), root mean square fluctuation (RMSF), and angular variance analysis. A set of key dynamical residues, defined by the most dynamically conserved positions, were identified in the gatekeeper 2 region. The highly conserved glycine (GLY79) in this region was predicted to underlie the local flexibility. To test it, additional simulations were performed for CypE and CypA, where GLY79 was mutated to alanine. Mutation of GLY79 to ALA79 leads to decreased flexibility of CypE and CypA during substrate binding (free → cis) but increased flexibility during catalysis (cis → ts). Dynamical changes occur in the mutated region, as well as in a distal loop downstream of the mutation site in sequence. Allosteric effects on catalysis by the mutation were also examined. Both mutated CypE and CypA show shifted binding free energies of substrate under distinct substrate peptide cis‐trans conformations. The results suggest a reversal in the direction of catalysis in the mutated CypE and enhanced catalytic activity in the mutated CypA.Support or Funding InformationNSF‐REU program award no. 1757933, NSF grant (MCB‐1517617)

Autologous esophageal mucosa with polyglycolic acid transplantation and temporary stent implantation for the prevention of esophageal stenosis after circumferential endoscopic submucosal dissection.

Autologous esophageal mucosa with polyglycolic acid transplantation and temporary stent implantation for the prevention of esophageal stenosis after circumferential endoscopic submucosal dissection.

Potential Risk in Combined Use of Capsule Retractors and Capsular Tension Rings

The aim of this study, present a complication associated with capsular tension ring (CTR) implantation after placement of capsule retractors. A 66-year-old man presented with progressive bilateral vision loss. He had no history of ocular trauma, and previous eye surgery. In ophthalmological examination bilateral large zonular deficiency had been noted in both eyes. The remaining ocular and medical history was unremarkable. Cataract extraction with IOL placement was performed in the right eye by the help of capsule retractors and CTR. On attempted removal one of the capsule retractor, it was discovered that the CTR had passed through the retractor's distal loop. Additional gently manipulation and rotation of the CTR through the retractor’s distal loop was ended with atraumatic removal of the capsule retractor. Though capsule retractors improve challenge of weak zonules during cataract surgery, the instrument itself may cause complications and unwanted problems when combined use with CTRs.

Integrative prediction of gene expression with chromatin accessibility and conformation data

BackgroundEnhancers play a fundamental role in orchestrating cell state and development. Although several methods have been developed to identify enhancers, linking them to their target genes is still an open problem. Several theories have been proposed on the functional mechanisms of enhancers, which triggered the development of various methods to infer promoter–enhancer interactions (PEIs). The advancement of high-throughput techniques describing the three-dimensional organization of the chromatin, paved the way to pinpoint long-range PEIs. Here we investigated whether including PEIs in computational models for the prediction of gene expression improves performance and interpretability.ResultsWe have extended our textsc{TEPIC} framework to include DNA contacts deduced from chromatin conformation capture experiments and compared various methods to determine PEIs using predictive modelling of gene expression from chromatin accessibility data and predicted transcription factor (TF) motif data. We designed a novel machine learning approach that allows the prioritization of TFs binding to distal loop and promoter regions with respect to their importance for gene expression regulation. Our analysis revealed a set of core TFs that are part of enhancer–promoter loops involving YY1 in different cell lines.ConclusionWe present a novel approach that can be used to prioritize TFs involved in distal and promoter-proximal regulatory events by integrating chromatin accessibility, conformation, and gene expression data. We show that the integration of chromatin conformation data can improve gene expression prediction and aids model interpretability.

Pouch of Douglas internal hernia successfully treated laparoscopically.

A rare case of internal herniation of a peritoneal defect in the pouch of Douglas is being reported. It presented as a case of intestinal obstruction, which after investigation, on laparoscopic exploration was found to be a case of internal hernia getting obstructed in the pouch of Douglas. It was successfully treated by marsupialisation of the defect laparoscopically. A 33-year-old female presented with pain abdomen and vomiting. On investigations, she was found to be having a small intestinal obstruction. Conservative trial failed and then diagnostic laparoscopy was done, which revealed a peritoneal defect in the pouch of Douglas with the incarcerated distal ileal loop. Contents were reduced, and laparoscopic marsupialisation of the peritoneal defect was done. A rare case of defect in peritoneum with no defect in muscular layer in the pouch of douglas. Internal hernia is being reported and successfully treated laparoscopically by marsupialisation for the first time.

Distal Loop Colonoscopy-Assisted Transanal Excision of Retained Spur after Duhamel's Procedure.

Distal Loop Colonoscopy-Assisted Transanal Excision of Retained Spur after Duhamel's Procedure.

Pneumatosis Intestinalis and Portal Venous Gas: An Unusual Complication of Fecal Impaction

We present an unusual case of pneumatosis intestinalis and portal venous gas due to massive fecal impaction resulting in ischemic infarction of three separate bowel segments. The patient was taken emergently to the operating room for an exploratory laparotomy with resection and anastomosis of a proximal loop of the jejunum, distal loop of the jejunum, and most of the terminal ileum, with creation of a loop ileostomy. In our review of the literature, there have been only two similar cases of pneumatosis intestinalis/portal venous gas caused by fecal impaction requiring operative intervention. J Curr Surg. 2020;10(1-2):10-12 doi: https://doi.org/10.14740/jcs398

A case report of endorectal displacement of a right ureteral stent following radiochemotherapy and Bevacizumab

BackgroundThe angiogenesis inhibitor monoclonal antibody Bevacizumab is presently the standard treatment for numerous neoplasms but particular toxicities are emerging, such as hypertension, haemorrhage, thromboembolism, gastrointestinal perforation, fistulae, and delayed wound healing. The addition of Bevacizumab to radio and chemotherapy has improved the overall survival rate in patients with metastatic, persistent or recurrent cervical carcinoma. However an increased risk of enteric or urinary fistula formation has been documented, related to hypoxia which is induced by the inhibition of angiogenesis. Moreover, previous pelvic surgery, repeated ureteral stenting and radiation are additional risk factors.Case presentationWe describe the remarkable case of a right ureteral stent displacement inside the rectum lumen in a patient treated with Bevacizumab for pelvic recurrence of cervical cancer. The patient was referred to our Urology Department with urinary sepsis and bilateral hydronephrosis. Right ureteral stent substitution was planned; at cystoscopy the distal loop of the stent was not visualized inside the bladder. The presence of the distal loop of the right ureteral inside the rectum was clearly demonstrated with a CT scan.ConclusionsSince Bevacizumab is increasingly used in the treatment of gynaecological neoplasms and indwelling ureteral stents are often required to treat or prevent ureteral compressions, similar cases are likely to be diagnosed and this complication should be considered in the management of advanced pelvic cancers.

Expression patterns of natriuretic peptides in pre-hibernating and hibernating Anatolian ground squirrel (Spermophilus xanthoprymnus) kidney.

Hibernation is characterized by marked suppression of renal function. Natriuretic peptides (NPs) are involved in the regulation of renal function. However, the role ofNPs in the renal function during hibernation remains unclear. We aimed to investigate the distribution patterns of atrial natriuretic peptide (ANP), brain natriuretic peptide (BNP) and C-type natriuretic peptide (CNP) in Anatolian ground squirrel (Spermophilus xanthoprymnus) kidneys during pre-hibernation and hibernation periods. Cortical proximal tubules showed weak ANP immunoreactivity, with moderate staining on the brush border during the pre-hibernation period. In the hibernation period, moderate ANP immunoreactivity was seen in cortical proximal tubules, with very weak reaction in hibernating cortical distal tubules, medullary proximal and collecting tubules. Cortical proximal and distal tubules of both periods had strong and weak BNP immunoreactivity, respectively. Medullary proximal, distal and Henle's loop segments showed very weak BNP immunoreactivity during pre-hibernation. Medullary distal, proximal and collecting tubules and Henle's loop segments had moderate staining during hibernation. In both periods, cortical proximal tubules displayed strong immunoreactivity to CNP. Distal tubules had moderate CNP staining during pre-hibernation, albeit weak staining during hibernation. Medullary proximal tubules exhibited moderate to strong immunoreactivity during pre-hibernation. Medullary distal and proximal tubules had weak and moderate CNP staining, respectively, during pre-hibernation. In both periods, Henle's loop segments displayed moderate CNP immunoreactivity. Glomeruli had similar weak ANP, BNP and CNP staining in both periods. These results suggest that heterothermic conditions differently affected the expression of NPs in the squirrel kidney. This different expression of NPs may contribute to the renal adaptation during hibernation.

Learning from Antibodies: Phage Host-Range Engineering

In a recent Cell paper, Yehl et al., 2019 find that bacteriophage T3 binds its host via four distal loops on the tail fiber. Randomization of these regions yield bacteriophage libraries capable of infecting resistant bacteria and preventing further resistance. These strategies may generate phage capable of infecting new hosts.

2610 Metastatic Melanoma Mimicking Enteritis

INTRODUCTION: Metastasis of melanoma to the gastrointestinal tract is rarely identified in clinical practice. We relay the case of a patient presenting with abdominal pain and leukocytosis with CT imaging initially suspicious for infectious or inflammatory bowel disease, but later confirmed to be small bowel melanoma. This report highlights the unpredictable nature of melanoma and underscores the need to be cognizant of imaging and endoscopy limitations in identifying disseminated disease. CASE DESCRIPTION/METHODS: A 59-year-old man with no past medical history presented to the ED with a one-day history of nausea associated with severe right lower quadrant abdominal pain. Labs showed leukocytosis to 20 K/uL. CT of the abdomen and pelvis showed significant wall thickening of a long segment of distal small bowel loop with adjacent fat stranding. He was discharged with antibiotics for presumed infectious enteritis and with gastroenterology follow up. Patient underwent ileocolonoscopy one month later that was significant for multiple polyps but otherwise normal appearing ileum and biopsies were negative for colitis or ileitis. Two months later, during follow up, patient underwent MR enterography which showed large mass measuring 9.0 × 7.1 × 7.4 cm in size in the small bowel, correlating with area of thickened bowel noted on CT previously (Figure 1). Patient underwent exploratory laparotomy with resection of small bowel mass with pathology positive for melanoma (Figure 2). Primary site was identified shortly thereafter as a cutaneous lesion in area of right upper back. DISCUSSION: Delayed diagnosis in this case hinged on unrevealing colonoscopy and CT findings describing only distal small bowel wall thickening concerning for enteritis due to infection or inflammatory bowel disease. Bender et al reported a sensitivity of 66% for contrast-enhanced CT in demonstrating intestinal metastatic deposits. A less common radiographic manifestation of metastatic melanoma infiltrating the serosa described in the literature includes segmental circumferential bowel thickening that can mimic the appearance of Crohn’s disease or intestinal enteritis, a characteristic that might explain the CT findings described in our patient. Also of note is the inability of endoscopy to uncover serosal metastases which is especially concerning as it is common for intestinal melanoma metastases to grow extraluminally.

2688 Blame It on the Migrating Stent: A Case Report

INTRODUCTION: Endoscopic implantation of plastic or metal stents is widely used to manage gastric and biliary disorders. However, complications from stent migration have also been well-documented. Biliary stents usually pass through the intestine without complications. In the case where invasive intervention is necessary, endoscopic retrieval is preferred to prevent surgical intervention. We report an acute abdominal pain case presumably from stent migration. CASE DESCRIPTION/METHODS: A 56 yo woman with past medical history of SMA chronic mesenteric ischemia status post revascularization and choledocholithiasis status post stent placement presented to the hospital for acute abdominal pain with nausea and vomiting. One month ago, she had a metal common bile duct stent placed for choledocholithiasis with biliary obstruction. Imaging showed showed the dislodged stent and mild mid-small bowel loop thickening with mid-small bowel stent. Initially, gastroenterology recommended watchful waiting and she was discharged home in stable condition. She returned to the hospital for persistent abdominal pain. Repeat imaging showed the dislodged common bile duct stent within the distal loop of small bowel, now appearing abnormally thickened and hyperemic but no evidence for bowel obstruction. After review with the surgery team, she was taken for combined mesenteric angiogram and exploratory laparotomy as the stent was inaccessible by endoscopy due to its location. On angiogram, all GI vasculature was patent, however a stricture was found adjacent to the stent. The strictured bowel was surgically resected and the stent was removed. The stricture was related to the ischemic changes that she previously suffered from prior revascularization. Abdominal pain improved and she was discharged home after tolerating a regular diet. DISCUSSION: This case illustrates that when abdominal pain is out of proportion to the physical exam, a broader differential would provide a different perspective. Initially, the diagnosis was homed in on the stent migration as the etiology of acute abdominal pain. Unfortunately, histories of previous abdominal surgeries and SMA revascularization were not explored until later. The stricture was only discovered after exploratory laparotomy. This case demonstrates premature diagnosis can be detrimental to patient care. It is imperative to understand the entirety of the patient’s history in order to make not only the correct diagnosis but to intervene in a timely manner to prevent morbidity and mortality.

1926 Gastrointestinal Bleeding in a Patient With Latent Tuberculosis and Remote T-Cell Lymphoma

INTRODUCTION: Immunosuppressed patients such as those with malignancies are susceptible to reactivation of tuberculosis (TB), which can affect the gut. CMV should also be considered as a cause of colitis in these patients. CASE DESCRIPTION/METHODS: A 68-year-old man with a history of T-cell lymphoma of the kidney and nasal cavity and latent TB presented with weight loss and cough. He was cachectic and had diffuse rhonchi in the lung bases. CT of the chest showed areas of cavitation. Multiple sputum cultures positive for acid-fast bacilli (AFB) and a positive mycobacterium tuberculosis (MTB) PCR confirmed active TB infection. The patient developed repeated episodes of melena with a hemoglobin level of 5.0 g/dL, MCV of 71.5 fL, iron of 4.5 ug/dL, transferrin saturation of 1%. Colonoscopy revealed extensive diverticulosis in the sigmoid colon and evidence of a prior cecectomy with ulceration of the ileocolonic anastomosis. Biopsies showed dense mature lymphocytic infiltrate and granulation tissue with no evidence of T-cell lymphoma. A CT revealed a 4 cm segment of terminal ileum with mild wall thickening, mucosal hyperenhancement and thickened folds of a distal loop of jejunum. Stool AFB culture and MTB PCR were both positive, indicating a probable diagnosis of TB enteritis. A push enteroscopy showed a 60 mm infiltrative lesion with ulcerated bases and three smaller lesions of similar appearance on the anterior wall of the stomach along with jejunal ulceration. Ulcer biopsies revealed large cells with inclusions consistent with CMV enteritis. Stains for AFB were also positive. Biopsies of the stomach lesions revealed an ulcerative oxyntic mucosa with dense atypical lymphoid infiltrate. Markers were consistent with a diagnosis of Burkitt’s Lymphoma (BL). The patient was treated with TB therapy, ganciclovir, and R-CHOP. DISCUSSION: Immunosuppression due to this patient’s BL likely led to dissemination and reactivation of latent TB and susceptibility to infection with CMV. The stomach and bowel are the most common sites of extranodal involvement in BL. The incidence of TB in malignancy is highest in non-Hodgkin’s lymphoma like BL. Bowel involvement in TB is seen in less than 5% of cases in the United States. Common endoscopic findings include ileal or ileocecal disease, non-confluent involvement of the colon, and nodular mucosa with areas of ulceration. The diagnosis can be made by biopsy showing caseating granulomas, a positive TB culture or PCR result, or by clinical suspicion with improvement following treatment.