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Biomedical subjects

A J M Watson

Publications and source records attributed to A J M Watson.

18 recordsLinked to original sources
PubMed2007

The role of positron emission tomography in the management of recurrent colorectal cancer: a review.

PURPOSE: Surgery remains the only option for potential cure in patients with recurrent colorectal cancer. Accurate staging modalities aid in the avoidance of futile surgery, which may result in considerable morbidity in patients with incurable disease. Current imaging techniques used in disease staging often are not sensitive enough to identify low-volume metastatic disease. This study reviews the role of positron emission tomography in the assessment of patients with suspected recurrent colorectal cancer. METHODS: A literature search using the PubMed, MEDLINE, and Embase database was performed, locating English language articles on positron emission tomography, positron emission tomography, recurrent colon, and/or rectal cancer. The references of these papers were searched manually for further references. RESULTS: Positron emission tomography is more sensitive and more specific than conventional diagnostic imaging for metastatic disease and local recurrence respectively. Studies confirm the superior ability of positron emission tomography scans compared with conventional diagnostic imaging in differentiating between scar tissue and invasive tumor. Positron emission tomography scanning is more sensitive and specific for the assessment of liver metastases (and probably in patients with lung metastasis) than conventional diagnostic imaging. Positron emission tomography is superior to conventional diagnostic imaging in the investigation of raised carcinoembryonic antigen in the postoperative patient and alters management in approximately 37 percent of patients with recurrent colorectal cancer. The limitations and cost effectiveness of positron emission tomography are discussed. CONCLUSIONS: Positron emission tomography scanning is emerging as the imaging modality of choice for patients being considered for surgery for locally recurrent colorectal cancer. Positron emission tomography has the greatest impact by detecting unresectable disease and thereby averting inappropriate surgery. Despite the high set-up costs, its use seems to be cost effective.

Colorectal Neoplasms↗
PubMed2007

Management of duodenal involvement in locally advanced colonic carcinoma.

Removal of locally advanced right-sided colonic carcinoma involving the duodenum can be challenging. There are few data on the optimal surgical approach. Adjacent organ involvement is associated with a poor prognosis and may be classified as inoperable with patients having palliative bypass procedures rather than primary resection. Survival is however improved after en bloc resection of adjoining viscera compared with intestinal bypass. We present a variety of surgical options depending on the extent of local invasion and the debility of the patient.

Colonic Neoplasms↗
PubMed2006

Regional localisation of p53-independent apoptosis determines toxicity to 5-fluorouracil and pyrrolidinedithiocarbamate in the murine gut.

Pyrrolidinedithiocarbamate (PDTC) enhanced the activity of 5-fluorouracil (5-FU) in a colorectal cancer xenograft model. Pyrrolidinedithiocarbamate also reduced gastrointestinal toxicity associated with 5-FU therapy in large but not small bowel. We sought to clarify the basis of this differential enteric toxicity. Apoptosis and mitosis were assessed on a cell positional basis in small and large intestinal crypts of p53 wild-type (+/+) and p53 null (-/-) mice 6, 12, 24, 36, 48 and 72 h after the administration of high (200 mg kg(-1)) or low (40 mg kg(-1)) dose 5-FU+/-250 mg kg(-1) PDTC. Regimens were chosen to model a single human dose and a weekly schedule. The effects of another antioxidant N-acetylcysteine (NAC) were also investigated. Large intestinal crypts affect apoptosis purely by p53-dependent mechanisms, whereas small intestinal crypts are able to initiate both p53-dependent and -independent pathways following treatment with 5-FU. Pyrrolidinedithiocarbamate and NAC antagonised p53-dependent but potentiated p53-independent apoptotic activity. Consequently, the proportion of surviving clonogens increased in the large but not in the small intestine. Regional availability of p53-dependent and -independent apoptotic pathways in small and large intestine together with separate modulation of these pathways by antioxidants explains the different regional enterotoxicity following 5-FU therapy.

Animals↗
PubMed2005

Outcomes after placement of colorectal stents.

BACKGROUND: Colonic stents are increasingly used to palliate or alleviate large bowel obstruction in patients with colon cancer and other obstructing lesions in whom a definitive surgical procedure is inappropriate. We report on the outcomes of a large group of patients who underwent deployment of a colon stent in a single institution by a single operator. PATIENTS AND METHODS: This was a retrospective observational cohort study of all patients undergoing colonic stenting between September 1995 and May 2002. Data collected included nature of pathology, type of stent used, procedure morbidity, patient survival and details of any definitive procedures performed after stenting. RESULTS: One hundred and seven patients were evaluated (58 male) with a median age of 75 years (range 36-99 years). A total of 112 stents were successfully deployed (46 as an emergency). Twelve patients had double stents inserted coaxially and overlapping. In 7 patients the stent could not be safely deployed. Eighty-seven patients had colorectal cancer, 13 patients had an extra-luminal malignancy, 5 had diverticular strictures and in 2 patients the pathology was unknown. At last review (May 2002) 18 patients were alive, 82 patients had died and 7 patients had been lost to follow-up. Of those patients who died, the median survival after stenting alone was 6 weeks (range 4 days-36 weeks). Ten patients underwent subsequent definitive surgery. Stent complications included, 2 colonic perforations, 3 stent occlusions and 4 stent migrations. CONCLUSION: Colonic stenting can be used effectively, with acceptable morbidity, to manage patients presenting with large bowel obstruction. In a smaller number of patients colon stents may safely temporize symptoms while definitive surgery is planned.

Adult↗
PubMed2005

Pathological audit of stapled haemorhoidopexy.

INTRODUCTION: Stapled haemorrhoidopexy is increasingly used for the surgical management of prolapsing haemorrhoids. Accurate placement of the staple line is essential to avoid involvement of the internal anal sphincter (IAS) and the pain sensitive squamous epithelium. The aim of this study was to correlate histology with symptomatic outcome after stapled haemorrhoidopexy. PATIENTS AND METHODS: A single pathologist reviewed one hundred and six consecutive rectal mucosal specimens. Each specimen was assessed for the presence of columnar, transitional and squamous epithelium as well as involvement of smooth and skeletal muscle. In November 2003 all patients were sent a previously validated postal questionnaire about haemorrhoidal symptoms and a Cleveland Clinic continence scale. Symptomatic outcome was compared between patients who did or did not have squamous epithelium involvement in their pathology specimens and were analysed by Mann-Whitney U-test. RESULTS: One hundred and six stapled haemorrhoidopexies were performed between June 2001 and September 2003. Eighty-four patients (79%) returned the questionnaire; 19 patients had squamous epithelium present in the pathology specimens. There was no significant difference between symptom or Cleveland Clinic scores in patients with or without squamous epithelium in their pathology specimens. Some specimens (n = 6) were found to have smooth muscle underlying squamous epithelium; this was interpreted as the presence of internal anal sphincter (IAS) within the specimen. There was no significant difference in Cleveland Clinic scores between this group and those without IAS involvement. CONCLUSION: This study has not demonstrated a long-term difference in symptomatic outcome or continence in patients who have squamous epithelium present in their stapled haemorrhoidopexy specimens.

Adult↗
PubMed2004

COOH-terminal 26-amino acid residues of progastrin are sufficient for stimulation of mitosis in murine colonic epithelium in vivo.

Transgenic mice (hGAS) that overexpress human progastrin are more susceptible than wild-type mice (FVB/N) to the induction of colonic aberrant crypt foci (ACF) and adenomas by the chemical carcinogen azoxymethane. We have previously shown significantly increased levels of colonic mitosis in hGAS compared with FVB/N mice after gamma-radiation. To investigate whether the effects of progastrin observed in hGAS colon require the presence of other forms of circulating gastrin, we have crossed hGAS (hg(+/+)) with gastrin knockout (G(-/-)) mice to generate mice that express progastrin and no murine gastrin (G(-/-)hg(+/+)). After azoxymethane, G(-/-)hg(+/+) mice developed significantly more ACF than control G(-/-)hg(-/-) mice (which do not express any forms of gastrin). G(-/-)hg(+/+) mice also exhibited significantly increased colonic mitosis both before and after exposure to 8 Gray Gy gamma-radiation or 50 mg/kg azoxymethane compared with G(-/-)hg(-/-). Treatment of G(-/-)hg(-/-) mice with synthetic progastrin (residues 21-101 of human preprogastrin) or G17 extended at its COOH terminus corresponding to the COOH-terminal 26-amino-acid residues of human preprogastrin (residues 76-101, G17-CFP) resulted in continued colonic epithelial mitosis after gamma-radiation, whereas glycine-extended gastrin-17 and the COOH-terminal tryptic fragment of progastrin [human preprogastrin-(96-101)] had no effect. Immunoneutralization with an antibody against G17-CFP before gamma-radiation significantly decreased colonic mitosis in G(-/-)hg(+/+) mice to levels similar to G(-/-)hg(-/-). We conclude that progastrin does not require the presence of other forms of gastrin to exert proliferative effects on colonic epithelia and that the portion of the peptide responsible for these effects is contained within amino acid residues 76-101 of human preprogastrin.

Amino Acid Sequence↗
PubMed2004

Comparison of three different procedures for antireflux surgery.

BACKGROUND: No long-term comparisons of the various open and laparoscopic antireflux procedures have been undertaken. The aim of this study was to compare symptomatic outcomes of three procedures for antireflux surgery performed at three specialist units. METHODS: Patients undergoing open Nissen fundoplication, laparoscopic Nissen fundoplication and laparoscopic anterior partial fundoplication between December 1993 and February 2001 were identified. Patient outcome was assessed by means of a postal questionnaire. This was a hypothesis-generating study. RESULTS: Three hundred and fifty-seven patients (80.0 per cent) completed the questionnaire, with no differences in response rate between centres. Overall, a mean of only 7.6 per cent of patients reported a poor outcome. Logistic regression revealed no significant differences amongst the three procedures for any symptoms, after allowing for the effect of time. There was a general increase in the DeMeester score with increasing time from operation. The incidence of revisional reflux surgery was similar in the three groups. CONCLUSION: Medium-term symptomatic outcome following all three procedures was similar. There was some recurrence of symptoms of gastro-oesophageal reflux with time for all procedures, suggesting that the effects of surgery diminish with time. The level of experience of the surgeon in a particular operation was more important than the procedure performed.

Adult↗
PubMed2004

Perforation of the terminal ileum: a possible complication of nicorandil therapy.

Recent reports have implicated nicorandil as a possible causative agent in the pathogenesis of anal and oral ulceration. We report a case of ulceration and perforation of the terminal ileum in a patient taking nicorandil. The possibility of an association between nicorandil therapy and gastrointestinal ulceration is discussed.

Dose-Response Relationship, Drug↗
PubMed2004

Colonic pouchography is not routinely required prior to stoma closure.

BACKGROUND: Colonic pouch formation with pouch-anal anastomosis is now regarded as the procedure of choice for restoration of intestinal continuity following anterior resection for low rectal cancers. The aim of this study was to review the necessity for routine colonic pouchography prior to closure of a diverting loop stoma. METHODS: This was a prospective study of 52 consecutive patients who underwent colonic pouch formation between 1 June 1999 and 31 May 2002, four of whom have subsequently died. Each pouch was assessed clinically and radiologically prior to stoma closure. RESULTS: There were no clinical anastomotic leaks. Forty-six of 48 surviving patients have had a colonic pouchogram and in no case was either a pouch or pouch-anal anastomotic defect identified. To date 40 patients have undergone stoma closure without an anastomosis-related complication. CONCLUSION: Following successful colonic pouch formation, routine study of the pouch by contrast radiology does not add to clinical assessment. As a consequence radiological imaging is unnecessary and can be omitted.

Adenocarcinoma↗
PubMed2001

Revisional surgery after failed laparoscopic anterior fundoplication.

BACKGROUND: Partial fundoplication may have functional advantages over a circumferential wrap but the reconstruction is more complex. Revisional surgery for recurrent reflux may be more difficult because of the additional suturing involved in the original operation. We report experience with revisional surgery in a large cohort of patients who had undergone laparoscopic anterior fundoplication and hiatal repair. METHODS: Between August 1993 and September 1999, 11 (3.5%) of 309 patients who had laparoscopic anterior fundoplication for uncomplicated gastroesophageal reflux disease required revisional surgery (1 open and 10 laparoscopic revisions). Data were retrieved from a prospective database supplemented by a postal questionnaire following the second operation. RESULTS: The operative findings were posterior hiatal disruption (n = 9), anterior paraesophageal hernia (n = 1), and inadequate initial esophageal mobilization (n = 1). There were no conversions to open surgery in the laparoscopic group. Ten (91%) of the respondents described the outcome of their repeat procedure as either good or excellent. All patients would recommend the repeat procedure to patients with similar symptoms. CONCLUSIONS: Revisional surgery after laparoscopic anterior fundoplication can be performed safely with a good outcome. Modifications to technique both in the primary procedure and for revision may decrease the incidence of early technical failure.

Fundoplication↗