Biomedical subjects

O N Tucker

Publications and source records attributed to O N Tucker.

7 recordsLinked to original sources

PubMed2006

The management of insulinoma.

BACKGROUND: Insulinomas are rare tumours. Their clinical presentation, localization techniques and operative management were reviewed. METHODS: An electronic search of the Medline, Embase and Cochrane databases was undertaken for articles published between January 1966 and June 2005 on the history, presentation, clinical evaluation, use of imaging techniques for tumour localization and operative management of insulinoma. RESULTS AND CONCLUSION: Most insulinomas are intrapancreatic, benign and solitary. Biochemical diagnosis is obtained during a supervised 72-h fast. Non-invasive preoperative imaging techniques to localize lesions continue to evolve. Intraoperative ultrasonography can be combined with other preoperative imaging modalities to improve tumour detection. Surgical resection is the treatment of choice. In the absence of preoperative localization and intraoperative detection of an insulinoma, blind pancreatic resection is not recommended.

Female↗

PubMed2005

The 'small for size' liver syndrome.

PURPOSE OF REVIEW: Small-for-size syndrome (SFSS) is a clinical syndrome described following liver transplantation (LT) and extended hepatectomy. New evidence has emerged documenting the importance of preoperative evaluation of functional liver mass, liver quality, influence of portal hypertension, and variations in surgical technique to improve outcome. RECENT FINDINGS: SFSS is characterized by postoperative coagulopathy and liver dysfunction due to insufficient functional liver mass. Recent radiologic advances allow accurate preoperative estimation of total, graft, and remnant liver volume (RLV). In adult-to-adult living donor liver transplantation (LDLT), a graft-to-recipient body weight ratio > or = 0.8% or graft weight ratio > or = 30% are important to avoid SFSS. Minimal functional RLV following extended hepatectomy is > or = 25% in a normal liver, and > or = 40% with preoperative liver dysfunction. Preoperative portal vein or hepatic artery embolization to increase RLV and function after extended hepatectomy, and the increasing use of parenchymal-sparing segmental resections have improved outcome. In LT, the evolving use of split livers, LDLT and marginal grafts has resulted in increased recognition of SFSS. This has led to a renewed interest in defining the pathophysiology, and the development of new surgical techniques to reduce its incidence. SUMMARY: Current radiologic imaging techniques can be used to evaluate liver volume and the risk of SFSS following LT and extended hepatectomy. Intraoperative techniques to predict postoperative dysfunction are emerging, and may be helpful in directing the use of pre-emptive surgical interventions. The future lies in the development of perioperative liver protection and support in predicted SFSS, and enhancement of healthy liver regeneration.

Adult↗

PubMed2004

Factors influencing the development of Barrett's epithelium in the esophageal remnant postesophagectomy.

BACKGROUND: Barrett's esophagus results from chronic reflux of both acid and bile. Reflux of gastric and duodenal contents is facilitated through the denervated stomach following esophagectomy, but the development of Barrett's changes in this model and the relationship to gastric and esophageal physiology is poorly understood. AIMS: To document the development of new Barrett's changes, i.e., columnar metaplasia or specialized intestinal metaplasia (SIM) above the anastomosis, and relate this to the recovery of gastric acid production, acid and bile reflux, manometry, and symptoms. PATIENTS AND METHODS: Forty-eight patients at a median follow-up of 26 months (range = 12-67) postesophagectomy underwent endoscopy with biopsies taken 1-2 cm above the anastomosis. The indication for esophagectomy had been adenocarcinoma (n = 27), high-grade dysplasia (n = 2), and squamous cell cancer (n = 19). Physiology studies were performed in 27 patients and included manometry (n = 25), intraluminal gastric pH (n = 24), as well as simultaneous 24-hour esophageal pH (n = 27) and bile monitoring (n = 20). RESULTS: Duodenogastric reflux increased over time, with differences between patients greater than and less than 3 years postesophagectomy for acid (p = 0.04) and bile (p = 0.02). Twenty-four patients (50%) developed columnar metaplasia and of these 13 had SIM. The prevalence of columnar metaplasia did not relate to the magnitude of acid or bile reflux, to preoperative neoadjuvant therapies, or to the original tumor histology. The duration of reflux was most significant, with increasing prevalence over time, with SIM in 13 patients at a median of 61 months postesophagectomy compared with 20 months in the 35 patients who were SIM-negative (p < 0.006). Supine reflux correlated with symptoms. CONCLUSIONS: The development of Barrett's epithelium is frequent after esophagectomy, is time-related, reflecting chronic acid and bile exposure, and is not specific for adenocarcinoma or the presence of previous Barrett's epithelium. This model may represent a useful in vivo model of the pathogenesis of Barrett's metaplasia and tumorigenesis.

Adenocarcinoma↗

PubMed2003

Granulomatous appendicitis.

Granulomatous inflammation of the appendix is uncommon. It can be caused by a variety of conditions, including systemic disorders such as Crohn's disease and sarcoidosis, and infections such as mycobacterium tuberculosis, yersinia pseudotuberculosis, parasites and fungi. Granulomatous appendicitis as an isolated pathological entity unassociated with systemic disease is rare. Isolated granulomatous inflammation of the appendix of unknown aetiology, otherwise known as idiopathic granulomatous appendicitis is extremely rare. Patients with this condition present with the typical signs and symptoms of acute appendicitis. We present a series of patients with isolated granulomatous inflammation of the appendix, and discuss the difficulties encountered in the management of this condition.

Adolescent↗

PubMed1999

Cyclooxygenase-2 expression is up-regulated in human pancreatic cancer.

A large body of evidence suggests that cyclooxygenase-2 (COX-2) is important in gastrointestinal cancer. The purpose of this study was to determine whether COX-2 was expressed in adenocarcinoma of the human pancreas. Quantitative reverse transcription-PCR, immunoblotting, and immunohistochemistry were used to assess the expression of COX-2 in pancreatic tissue. Levels of COX-2 mRNA were increased by >60-fold in pancreatic cancer compared to adjacent nontumorous tissue. COX-2 protein was present in 9 of 10 cases of adenocarcinoma of the pancreas but was undetectable in nontumorous pancreatic tissue. Immunohistochemical analysis showed that COX-2 was expressed in malignant epithelial cells. In cultured human pancreatic cancer cells, levels of COX-2 mRNA and protein were induced by treatment with tumor-promoting phorbol esters. Taken together, these results suggest that COX-2 may be a target for the prevention or treatment of pancreatic cancer.

Adenocarcinoma↗

PubMedDate not supplied

Giant solitary non-parasitic cyst of the liver.

BACKGROUND: Cystic diseases of the liver and intrahepatic biliary tree are uncommon. The majority of cases are detected only when patients become symptomatic, or as an incidental finding on radiological imaging. METHODS: We discuss the case of a 25-yr-old female with a centrally located giant liver cyst causing obstructive jaundice, and briefly discuss the management options in the treatment of this uncommon problem. RESULTS AND CONCLUSIONS: Intervention is recommended in patients with symptomatic simple cysts of the liver. Surgical cystectomy is the treatment of choice for large deep seated cysts.

Adult↗

PubMedDate not supplied

Unusual presentation of an appendiceal malignancy.

Primary malignant epithelial tumors of the appendix are uncommon. The most common presentation of appendiceal malignancy is right lower abdominal pain suggestive of acute appendicitis. Presentation caused by loco-regional spread with involvement of neighboring organs is rare. We present the case of a 48-year-old woman with an appendiceal malignancy who presented with symptoms and signs suggestive of complicated diverticular disease with an enterovaginal fistula. From a review of the literature, this is the first report of an appendiceal malignancy presenting in this manner.

Adenocarcinoma, Mucinous↗