Search PubMed⌕ Search

Biomedical subjects

S D Ryder

Publications and source records attributed to S D Ryder.

At least 37 records · Page 2Linked to original sources
PubMed1998

Peanut ingestion increases rectal proliferation in individuals with mucosal expression of peanut lectin receptor.

BACKGROUND & AIMS: The Thomsen-Friedenreich blood group antigen (galactose beta 1,3-N-acetyl galactosamine alpha-) acts as an oncofetal antigen in the colonic epithelium, with low expression in normal adult epithelia but increasing to fetal levels of expression in hyperplasia or malignancy. Peanut lectin is one of the commonest dietary lectins that binds this antigen. The aim of this study was to determine whether peanut ingestion can alter rectal epithelial proliferation. METHODS: Thirty-six patients with normal colonic mucosa consumed 100 g of peanuts each day for 5 days. Rectal mitotic index was measured before and after ingestion, and changes in proliferation were correlated with immunohistochemical detection of lectin receptor expression by colonocytes and fecal lectin activity as measured by hemagglutination assay. RESULTS: Peanut ingestion caused a 41% increase in rectal mucosal proliferation in individuals with macroscopically normal mucosa who express TF antigen in their rectal mucosae (10 of 36 patients studied). The proliferative response correlated with fecal hemagglutinating activity, and peanut lectin could be shown immunohistochemically within the rectal mucosa. CONCLUSIONS: The common expression of galactose beta 1,3-N-acetyl galactosamine alpha- by hyperplastic and neoplastic epithelia may therefore be functionally important because it allows interaction with mitogenic dietary lectins. This could be an important mechanism for the association between diet and colorectal cancer.

Adult↗
PubMed1998

Hepatitis G infection: role in cryptogenic chronic liver disease and primary liver cell cancer in the UK. Trent Hepatitis C virus Study Group.

Hepatitis G virus (HGV) is a flavivirus that can cause acute hepatitis and persistent infection but its role in chronic liver disease or primary liver cancer is unproven. In this study we have examined the prevalence of HGV RNA in the serum of patients with hepatitis C virus (HCV) infection and in patients with cryptogenic chronic liver disease, including non-alcoholic steatohepatitis (NASH), and in patients with HCV-related hepatocellular carcinoma (HCC) and HCC arising in patients with cryptogenic liver disease. One-hundred and thirty patients who were positive for antibody to HCV (anti-HCV), 54 patients with cryptogenic chronic liver disease (including 17 patients with NASH) and 46 patients with hepatitis C-related (n = 27) or cryptogenic liver disease-related HCC (n = 19) were studied. HGV RNA was detected using nested reverse transcriptase-polymerase chain reaction (RT-PCR) and was found in 16.1% of patients with HCV infection. HGV RNA was not detected in any patient with cryptogenic liver disease. In patients with HCC, 7/34 samples were positive for HGV RNA and six out of seven HGV-positive subjects also had HCV infection. Only one patient with HCC in cryptogenic liver disease was positive for HGV RNA. Hence, cryptogenic liver disease in the UK is not caused by HGV/GBVc infection. It seems unlikely that HGV plays a significant role in hepatocarcinogenesis.

Carcinoma, Hepatocellular↗
PubMed1997

The long-term management of patients with bleeding duodenal ulcers.

BACKGROUND: Gastrointestinal haemorrhage is a common complication of duodenal ulcers. Patients who bleed are at substantial risk of recurrent bleeding. AIM: To determine whether appropriate therapeutic steps were taken to reduce the risk of recurrent haemorrhage in patients with a bleeding duodenal ulcer. METHODS: The management of patients surviving a duodenal ulcer bleed in the University Hospital. Nottingham, was assessed by case-note review before (1993) and after (1995-1996) institution of clinical guidelines. The following measures aimed at reducing the risk of recurrent haemorrhage were considered appropriate: stopping non-steroidal anti-inflammatory drugs (NSAIDs) when these were implicated in bleeding; successful eradication of Helicobacter pylori if present; and long-term maintenance acid-suppression therapy. RESULTS: In 1993, appropriate steps were taken to reduce the risk of recurrent haemorrhage in only 48% of cases. Following the institution of guidelines, management improved significantly in 1995-1996 (appropriate in 83% of cases, P < 0.001), was associated with increased referral to gastroenterologists (P < 0.001), improved patient compliance with follow-up (P < 0.05), and more rigorous attempts to identify (P < 0.001) and ensure clearance (P < 0.001) of H. pylori. CONCLUSION: In this study, inadequate long-term management of patients with a bleeding duodenal ulcer was common. This was to a failure to adopt strategies aimed at reducing the risk of ulcer relapse and rebleeding. The quality of care improved significantly following the institution of guidelines and encouragement to refer to gastroenterologists.

Aged↗
PubMed1996

Chemoembolisation with lipiodol and doxorubicin: applicability in British patients with hepatocellular carcinoma.

Chemoembolisation has been extensively used as primary treatment for unresectable hepatocellular carcinoma (HCC). In this unit, 185 patients with a new diagnosis of HCC not amenable to surgery were seen between 1988 and 1991. Intended therapy for these patients was chemoembolisation with doxorubicin (60 mg/m2) and lipiodol, repeated at six week intervals until it was technically no longer possible or until complete tumour response had been obtained. Chemoembolisation was possible in 67 of the 185 (37%). Reasons for exclusion were portal vein occlusion (n = 36), decompensated cirrhosis (n = 44), distant metastases (n = 5), diffuse tumour or unsuitable anatomy (tumour or vasculature) (n = 11), patient refusal (n = 11), and other (n = 11). Patients excluded from treatment survived for a median of 10 weeks (range 3 days-19 months). In patients treated, 18 had small HCC (< 4 cm) and 49 had large or multifocal HCC. Chemoembolisation was carried out a median of two sessions for small and three sessions for large tumours. Ten of 18 patients with small HCC showed a 50% or greater reduction in tumour size. Five of 49 patients with large or multifocal tumours showed a response to treatment. Median overall survival for treated patients was 36 weeks (range 3 days-4 years). One patient has subsequently undergone liver transplantation with no recurrence and minimal residual disease at transplantation. Two other patients are alive three years after chemoembolisation, one with no evidence of recurrent disease. No patient was thought suitable for surgery after their response to chemoembolisation. Chemotherapy related complications were seen in 22%. Complications were significantly more common in patients with larger tumours and poor liver reserve. Five patients died as a result of chemotherapy related complications. In conclusion, only one third of UK patients with unresectable HCC are treatable by chemoembolisation. Results with small tumours are encouraging, with a high response rate and the possibility of surgical intervention in previously inoperable disease. Large tumours, however, show a poor response and a significant incidence of side effects, suggesting that this treatment offers little benefit in advanced disease.

Antineoplastic Agents↗
PubMed1996

p53 Protein overexpression in cholangiocarcinoma arising in primary sclerosing cholangitis.

The protein encoded by the p53 tumour suppressor gene plays an important part in the regulation of cell growth. Abnormalities of this gene represent one of the most common genetic changes in the development of human cancers. This study investigated the expression of p53 protein in cholangiocarcinoma arising in association with primary sclerosing cholangitis (PSC). Of the 14 patients with cholangiocarcinoma studied, 13 had underlying PSC. The expression of p53 protein was detected immunohistochemically in paraffin wax embedded liver specimens, after microwave pretreatment. The expression of p53 protein was shown in the cholangiocarcinoma tissue of 11 of 14 (78.5%) patients. In five of 10 patients, the accumulation of p53 protein highlighted the presence of neoplastic cells in biliary tissue separate from the main tumour. These cells were mainly located in the septal bile ducts or in the accessory glands, or both, but occasionally also in large portal areas at the periphery of nerves and lymphatics, and in one case in the mucosa of an extrahepatic bile duct. No p53 protein was detectable in liver tissue obtained at the time of transplantation in 15 patients with PSC but not cholangiocarcinoma. These results show that cholangiocarcinoma development in PSC is commonly associated with abnormalities of p53 and that these occur at a late stage in the development of the malignant process. Staining for p53 protein could represent an additional criterion for the diagnosis of cholangiocarcinoma development in patients with PSC.

Adult↗
PubMed1996

Use of specific ELISA for the detection of antibodies directed against p53 protein in patients with hepatocellular carcinoma.

AIMS: To analyse the significance of antibodies to p53 protein as a serological marker for changes in p53 gene expression in patients with hepatocellular carcinoma. METHODS: Thirty eight patients with hepatocellular carcinoma, 19 showing accumulation of p53 protein by immunohistochemistry and 19 having no accumulation, were studied. The presence of anti-p53 was tested using a novel ELISA utilising a recombinant p53 protein as a capture system and verified by western blotting. p53 gene mutations were sought by single strand conformational polymorphism and DNA sequencing analyses. RESULTS: Of 19 patients with p53 protein accumulation in tumour tissue, 10 (52%) had antibodies to p53 in serum by ELISA. Four patients with p53 negative immunohistochemistry also had detectable anti-p53. Western blot analysis confirmed the specificity of the ELISA positive serum samples. The presence of anti-p53 was independent of serum alpha-fetoprotein and was detected in 50% of small tumours while only 8% were alpha-fetoprotein positive. Mutations affecting exons 5 and 6 seem to be more frequently associated with development of anti-p53, than mutations in exons 7 or 8. CONCLUSIONS: The ELISA for anti-p53 is a convenient and specific tet for the detection of humoral response to alterations in p53 gene expression and could be of value in the diagnosis and characterisation of patients with hepatocellular carcinoma.

Antibodies, Neoplasm↗
PubMed1995

Experience of orthotopic liver transplantation and hepatic resection for hepatocellular carcinoma of less than 8 cm in patients with cirrhosis.

Fifteen patients with cirrhosis underwent orthotopic liver transplantation for small hepatocellular carcinoma (HCC) and 12 patients with cirrhosis underwent hepatic resection for similar HCC. All tumours were of the non-fibrolamellar variant. The majority of the patients in the transplant group had Child's grade B or C cirrhosis. Median follow-up was 37 months with a minimum of 18 months. Eleven of 12 patients in the resection group had Child's grade A cirrhosis. Median follow-up was 29 months with a minimum of 16 months. Actuarial survival rates at 1 and 3 years for the transplanted patients were 80 and 63 per cent and all were tumour free. Tumour recurrence rate was 15 per cent. The overall 1- and 3-year tumour-free survival rates for patients in the resection group were 61 and 33 per cent. Tumour recurrence rate was 45 per cent. The results show orthotopic liver transplantation to be an important surgical option in cirrhotic patients with small HCC, particularly in those with moderate to severe hepatic decompensation.

Adult↗
PubMed1995

The economic and quality-of-life benefits of Helicobacter pylori eradication in chronic duodenal ulcer disease--a community-based study.

A policy of Helicobacter pylori eradication in patients with duodenal ulceration on long-term acid-suppressing therapy was evaluated in a prospective study amongst a general practice population, with particular reference to economic and quality-of-life benefits. One hundred and sixty-eight patients on long-term acid-suppressing therapy had chronic duodenal ulcer disease of whom 88 were eligible for the study; 45 patients attended for review, with 42 testing positive for H pylori (as assessed by 13C-urea breath test). The median duration of acid-suppressing therapy was six years (maximum 15 years); 47.6% of the patients were using additional antacids and 80.9% still experienced epigastric discomfort. Two-thirds (28/42) of the patients eradicated H pylori. Successful eradication was associated with a highly significant reduction in all symptoms. At 12 months follow-up, heartburn had decreased from 28.7% to 7.1%, epigastric discomfort from 75% to 3.6%, nausea from 32.1% to 0% and wind from 50% to 0%. Of the patients that eradicated H pylori 96.4% reported an improvement in their general health compared to none of those that remained H pylori positive. Successful H pylori eradication therapy scored higher on satisfaction ratings than long-term acid-suppressing therapy. Eradication of H pylori resulted in 27/28 patients being able to discontinue acid-suppressing therapy, representing a 5.8% reduction in the use of such drugs per year in the local general practice population. A policy of H pylori eradication in chronic duodenal ulcer disease reduces the use of long-term acid-suppression therapy in general practice. This has important financial implications as well as offering considerable symptomatic benefits to the patients and improving their quality of life.

Adult↗
PubMed1995

Increased rate of sialylation of colonic mucin by cultured ulcerative colitis mucosal explants.

Sialylation of mucus glycoproteins confers charge and increased resistance to enzymatic degradation. The hypothesis that mucus sialylation might be altered in ulcerative colitis has been studied using in vitro culture of mucosal biopsies for 24 h with 3H N-acetyl mannosamine as a specific sialic acid precursor. Rectal biopsies were obtained at colonoscopy from patients with clinically inactive ulcerative colitis (n = 9) and controls (n = 12) who were patients found to have a normal colonoscopy performed for iron deficiency anaemia or altered bowel habit. The incorporation of 3H N-acetyl mannosamine into mucin was increased in ulcerative colitis (n = 9; 150; 113.3-393.2 dpm/micrograms mucin, median and interquartile ranges), compared with controls (n = 12; 33.6; 19.7-68.4 dpm/micrograms; p < 0.01). The ratio of incorporation into mucin of 3H N-acetyl mannosamine/14C N-acetyl galactosamine was also increased in ulcerative colitis (3.27; 1.93-4.98 dpm/dpm), compared with controls (1.35; 1.24-1.7 dpm/dpm; p < 0.001) suggesting that the increased incorporation of N-acetyl mannosamine probably reflects an increase in the average extent of sialylation per mucin oligosaccharide chain rather than an increase in the number of oligosaccharide chains. This increase in mucin sialylation seems unlikely to have a pathogenic role in the development of colitis but provides further evidence for the similarity between the alterations that occur in ulcerative colitis, colonic polyposis and malignancy.

Acetylgalactosamine↗
PubMed1995

Abnormal mucosal glycoprotein synthesis in inflammatory bowel diseases is not related to cigarette smoking.

Patients with ulcerative colitis are usually non- or ex-smokers in contrast to Crohn's disease where smoking is common. Abnormalities of quantity and quality of intestinal mucus have been postulated in the pathogenesis of these diseases. It is possible that smoking habit may exert its effects via changes in mucus in inflammatory bowel disease. We have therefore studied incorporation of N-acetylglucosamine into synthesized colonic mucin in explants from 85 controls with normal colonoscopic appearances and histology, including 27 smokers and 58 nonsmokers, 36 patients with ulcerative colitis and 19 with ileocolonic Crohn's disease over 24 h in tissue culture. Incorporation of N-acetylglucosamine into normal explants was 31.3 +/- (SD) 7.1 dpm/microgram biopsy protein, incorporation was increased in patients with active Crohn's disease (mean 41.2 +/- (SD) 10.4 dpm/microgram biopsy protein, p = 0.003), decreased in inactive ulcerative colitis (mean 24.1 +/- 7.8 dpm/microgram biopsy protein, p = 0.0006) but normal in active ulcerative colitis (mean 35.0 +/- 13.8 dpm/microgram biopsy protein, p = 0.44). No significant relationship was found between cigarette smoking habits and mucus synthesis in controls with normal mucosa (nonsmokers, n = 58, mean 31.0 +/- (SD) 7.52 dpm/microgram biopsy protein; smokers, n = 27, mean 31.8 +/- (SD) 6.1 dpm/microgram biopsy protein, p = 0.9). This study shows that mucus glycoprotein synthesis is reduced in inactive ulcerative colitis, rising to normal levels in active disease and that synthesis is increased in Crohn's disease. There is no effect of smoking on mucus synthesis by control biopsies suggesting that the differences seen in inflammatory bowel disease are not related to cigarette smoking.

Acetylglucosamine↗
PubMed1995

Hepatocellular carcinoma complicating autoimmune hepatitis: role of hepatitis C virus.

The risk of hepatocellular carcinoma in autoimmune hepatitis is low, even in patients with long-standing cirrhosis. Because of the increasing recognition of an association of hepatitis C virus (HCV) with autoimmune hepatitis, at least in some geographical areas, and with hepatocellular carcinoma (HCC) (hepatoma), we have examined eight cases (4 male, 4 female) who presented between 1985 and 1993 with hepatoma complicating autoimmune hepatitis. All had steroid-responsive autoimmune hepatitis with serum anti-smooth muscle and anti-nuclear autoantibodies. Median duration of disease was 17.1 years, and all patients had biopsy-proven cirrhosis. One patient had a history of intravenous drug abuse, and four had previously received blood transfusions. Serum samples (stored at -20 degrees C from up to 9 years before diagnosis of hepatoma) were tested for anti-hepatitis C virus antibodies by a second-third-generation assay and for HCV RNA by the polymerase chain reaction method using primers from the 5'noncoding region. Tissue from liver adjacent to tumor areas was subjected to polymerase chain reaction along with tissue from previous liver biopsy specimens (taken up to 19 years before diagnosis of hepatoma) in all patients. Six patients had evidence of HCV infection: four seropositive for HCV RNA (two of whom were also anti-HCV positive) and two seronegative for HCV RNA and anti-HCV but with HCV RNA in liver tissue at presentation with hepatoma. Retrospective testing showed probable acquisition of HCV through blood transfusion in the four transfused patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1994

Long term acid suppressing treatment in general practice.

OBJECTIVE: To determine the current practice in selected general practices for prescribing long term (> 6 months) treatment to suppress gastric acid secretion. SETTING: Seven general practices in the Harrow area that always or usually refer to Northwick Park Hospital. SUBJECTS: 60,148 patients on lists of the general practices. DESIGN: Identification of patients receiving long term treatment through repeat prescribing data, followed by a manual and computer survey of patients' notes for indications and investigations. Patient compliance and views on treatment were sought by a postal questionnaire. MAIN OUTCOME MEASURES: Indications for treatment, treatment given, investigations undertaken before and during treatment. RESULTS: 492 patients (0.82% of the population) were taking long term acid suppressing treatment. The most common diagnosis was duodenal ulcer disease (183 (37%) of all patients); oesophageal disease (118 (24%)) was also common. 93 patients (19%) were treated for abdominal pain where no diagnosis had been reached or who had only a diagnosis of gastritis on endoscopy. Ranitidine was prescribed in 394 (80%) patients. 298 (74%) patients found treatment helpful, but 108 (27%) had a poor understanding of their diagnosis. 317 patients (78%) took their drug as prescribed. 37 patients were also taking prescribed non-steroidal anti-inflammatory drugs and an additional 43 patients took regular aspirin or ibuprofen without prescription. CONCLUSIONS: Long term acid suppressing treatment is common, and a substantial number of patients are taking these drugs long term without a diagnosis having been reached. It is hoped that protocols for investigation and treatment will improve these figures. Patients need to be better informed about their disease and the possible adverse effects of taking non-steroidal anti-inflammatory drugs in acid related upper gastrointestinal disease.

Abdominal Pain↗
PubMed1994

Accuracy of radiology in detection of hepatocellular carcinoma before liver transplantation.

BACKGROUND/AIMS: Recurrence of hepatocellular carcinoma (HCC) after orthotopic liver transplantation (OLT) depends on tumor size and number; the accuracy of radiology in detecting HCC is uncertain. This study compared tumor size at radiological and pathological examination in 30 patients with HCC who underwent OLT. METHODS: Pre-OLT radiology included ultrasonography (US), computerized tomography (CT), and hepatic angiography (HA). Sensitivity of radiology was calculated by comparison with pathology. RESULTS: Radiology missed HCC in two patients but showed five with small (< 4 cm) and eight with large (> 4 cm) lesions. Multicentricity was shown in 15 cases at radiological examination and 24 at pathological examination, including one incidental and 4 of 5 radiologically small HCC. Mean tumor bulk was 3.4, 74, 338, and 1375 cm3, respectively, in patients with incidental, small, large, and multicentric HCC at radiology. Sensitivities of US, CT, and HA in detection of HCC (and multicentricity) were 80% (16.6%), 86.6% (58.3%), and 90% (58.3%). No recurrence was found in patients with incidental or small HCC; even when multicentric. CONCLUSIONS: US, CT, and HA identified patients with small or large tumor bulk, but sensitivity in detecting satellites was poor; their finding in patients with radiologically small or incidental tumors does not affect outcome. The failure of US, CT, and HA to detect satellites must be considered in patients undergoing partial hepatectomy for HCC.

Carcinoma, Hepatocellular↗
PubMed1994

Proliferative responses of HT29 and Caco2 human colorectal cancer cells to a panel of lectins.

BACKGROUND/AIMS: Altered lectin binding is common in malignant and premalignant epithelia, but its functional significance is unclear. This study examined the proliferative effects of four lectins on HT29 and Caco2 colon cancer cells. METHODS: Proliferation was assessed in log growth and confluent culture by thymidine incorporation and cell counts. Peanut agglutinin (PNA) binding was characterized by Scatchard analysis and electrophoresis of lectin affinity-purified cell surface-radiolabeled preparations. RESULTS: PNA, 5 micrograms/mL, increased thymidine incorporation in HT29 but had no effect on Caco2. Wheat germ agglutinin and concanavalin A stimulated proliferation slightly at 0.5-1.0 microgram/mL but were inhibitory at higher concentrations. Ulex europaeus 1 had no significant effect. Similar results were obtained when proliferation was assessed by cell counts and with confluent cell cultures. Scatchard analysis with both cell lines showed multisite best fit models with similar binding affinities. Three PNA-binding glycoproteins were identified in both cell lines, but two were of lower molecular weight in HT29 than in Caco2. Membrane preparations from a resected colorectal cancer contained a 30-kilodalton PNA-binding glycoprotein similar to that in HT29 cells. CONCLUSIONS: Lectins are plentiful in the normal diet and often escape digestion. This study suggests that altered expression of lectin receptors, particularly the upregulation of PNA receptor seen in colonic malignancy and hyperplasia, may have an important role in growth modulation.

Carcinoma↗
PubMed1994

Peanut lectin stimulates proliferation in colonic explants from patients with inflammatory bowel disease and colon polyps.

BACKGROUND/AIMS: The TF antigen (galactose-beta 1,3-N-acetylgalactosamine alpha) is overexpressed in malignant and premalignant colonic epithelium. Previous studies have shown that peanut lectin (PNA), which binds TF, is mitogenic for normal human colonic epithelium. This study aimed to determine its effect on abnormal colonic epithelium. METHODS: Crypt cell proliferation rate (CCPR) was measured using vincristine arrest and mucus synthesis by incorporation of radiolabeled N-acetyl glucosamine in colonoscopic biopsy specimens cultured with and without PNA. RESULTS: Unstimulated CCPR was greater in patients with ulcerative colitis than in patients with histologically normal colon. PNA (25 micrograms/mL) produced a 25% average increase in CCPR in tissues from patients with ulcerative colitis, Crohn's disease, and colonic polyps. In ulcerative colitic biopsy specimens incubated with PNA, CCPR increased to more than double that of unstimulated normal colonic epithelium. In controls, the response to PNA was greater when adjacent specimens were positive for PNA (avidin-biotin) histochemistry than when they were negative. Mucus synthesis was increased by an average 75% over 24 hours by PNA. CONCLUSIONS: Increased TF expression by premalignant epithelia may allow stimulation of proliferation by dietary galactose N-acetylgalactosamine-binding lectins. If the hyperplasia-dysplasia cancer hypothesis is correct, this could explain the increased colon cancer risk in ulcerative colitis.

Acetylglucosamine↗
PubMed1994

Liver disease.

Explore the source record for details and available documents.

Carcinoma, Hepatocellular↗
PubMed1993

Stress proteins in colorectal mucosa. Enhanced expression in ulcerative colitis.

Stress (heat shock) proteins are ubiquitous intracellular proteins that can be induced in vitro by physiological stress events that occur during inflammation. We have used an indirect immunoperoxidase method to locate 60-kDa stress proteins in biopsies taken from normal and inflamed colorectal mucosa. An anti-60-kDa monoclonal antibody (ML30) produced specific staining of surface epithelial cells localized to the site of the Golgi apparatus. In ulcerative colitis, there was an increased concentration of this stress protein compared with controls (P < or = 0.002) and also with a small group of active Crohn's colitis (P < or = 0.01), but no relationship between its concentration and disease activity. All biopsies also showed staining of goblet cells by ML30, suggesting a possible cross-reaction with mucin; electroblotting of crude but not purified mucin showed a faint 60-kDa band with ML30. We conclude that the 60-kDa stress protein is present in normal colorectal epithelial cells and is markedly induced in vivo in ulcerative colitis. Further, we suggest that since the 60-kDa protein functions as a molecular chaperone, it may associate with colonic mucin aiding in its synthesis and/or secretion.

Adult↗