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Biomedical subjects

J D Hardcastle

Publications and source records attributed to J D Hardcastle.

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

Gastric carcinoid expresses the gastrin autocrine pathway.

BACKGROUND: In gastric adenocarcinoma the gastrin autocrine-paracrine pathway is activated. As enterochromaffin-like (ECL) cells originate from the same stem as epithelial cells, the aim of this study was to determine if the gastrin autocrine pathway is present in gastric carcinoid. METHODS: Samples from ten patients with gastric carcinoid were assessed by immunocytochemistry using primary antibodies directed against gastrin precursors and the gastrin/cholecystokinin B receptor and detected using the avidin-biotin immunoperoxidase system. RESULTS: A high level of expression of precursor and mature gastrin peptides, together with the gastrin receptor, was seen in all carcinoids screened. CONCLUSION: In common with the glandular epithelium of the stomach the gastrin gene is activated during the neoplastic process in ECL cells. This finding may explain why some carcinoids do not regress after surgical procedures that lower serum gastrin. Antigastrin agents may be a useful treatment for carcinoid either in their own right or as an adjunct to surgery.

Adult↗
PubMed1998

Should we be screening for colorectal cancer?

Mass population screening for asymptomatic neoplastic disease is now national policy in the UK for breast cancer and has been established for many years in the early diagnosis of carcinoma of the cervix. Cancer screening is based on the concept that treatment is more effective when the disease is localised and aims to detect it when it is at a less advanced clinico-pathological stage prior to the development of symptoms. Because colorectal cancer develops in benign adenomatous polyps which are often amenable to endoscopic resection, screening may both reduce the incidence of the disease as well as improving outcome from it. Flexible sigmoidoscopy screening focuses mainly on the detection of potentially malignant adenomas, their endoscopic removal producing a decrease in colorectal cancer incidence. It is a promising approach but conclusive data on effectiveness from a Medical Research Council-sponsored multicentre randomised controlled trial will not be available before 2006. Faecal occult blood testing aims to preferentially detect early stage invasive disease. Three randomised controlled trials of faecal occult blood screening show that the disease can be detected earlier in its development leading to reduced mortality from the disease--and that this is achieved at reasonable cost. The Department of Health is currently giving consideration to its national implementation.

Colorectal Neoplasms↗
PubMed1998

Endoscopic screening of relatives of patients with colorectal cancer.

BACKGROUND: The risk of colorectal cancer is higher among relatives of those affected. The neoplastic yield reported from screening such individuals varies enormously between studies and depends on the age and strength of the family history of those screened. AIMS: To ascertain the neoplastic yield of endoscopic screening of first degree relatives of patients with colorectal cancer by age and familial risk. SUBJECTS: A total of 330 individuals with a family history of colorectal cancer. METHOD: Endoscopic screening conducted according to a protocol. RESULTS: Adenomas were found in 12%, and adenomas larger than 1 cm in 8%, of "high risk" individuals screened primarily by colonoscopy. Of those with neoplasia, 26% had lesions at or proximal to the splenic flexure. Neoplasia was found in 9.5% of individuals at lower familial risk, screened primarily by 60 cm flexible sigmoidoscopy, 4% of whom had neoplasia larger than 1 cm in size or cancer. Neoplastic yield was greatest in the fourth and fifth decades in those at highest risk, but increased with age in those at lower risk. CONCLUSIONS: For individuals with two or more first degree relatives, or relatives who have developed colorectal cancer at a young age, colonoscopy appears to be the only satisfactory method of screening, but 60 cm flexible sigmoidoscopy may be useful in those at lower levels of risk.

Adenoma↗
PubMed1997

The effect of onapristone, a progesterone antagonist, on the growth of human gastrointestinal cancer xenografts.

Onapristone is a progesterone antagonist which inhibits the growth of mammary tumours in mice. The effect of Onapristone and concomitant oestrogen (E2) supplements on the growth of five human gastrointestinal cancer xenografts was examined. E2 stimulated RD19 (gastric tumour) tumour growth in female mice and tumours grew less well when also treated with Onapristone (P < 0.05). Onapristone had no effect on male mice bearing RD19 tumours or mice of either sex bearing MKN45G (gastric) tumours. PAN-1 (pancreatic) tumours were significantly stimulated by E2 (by 64% of control, P = 0.02) and Onapristone treatment inhibited E2 stimulated growth (52% reduction of E2 control, P > 0.05). C146 (colorectal) tumour growth was not stimulated by E2 nor inhibited by Onapristone. E2 stimulated formation of AP5LV (colorectal) tumour nodules (in lungs) (mean 38-52, P = 0.001). Onapristone significantly reduced the number of nodules (mean 32, P < 0.05) only in female mice not given E2. Xenografts of some GI tumour cell lines grow at different rates in male and female mice. E2 may cause additional growth stimulation and E2 stimulated growth can be reversed by Onapristone to basal levels.

Analysis of Variance↗
PubMed1997

Chemical and immunological testing for faecal occult blood in screening subjects at risk of familial colorectal cancer.

BACKGROUND: People with a family history of colorectal cancer have an increased risk of the disease themselves. Many centres are advocating family history screening by endoscopy. AIMS: The performance of chemical and immunological faecal occult blood tests (Haemoccult and Hemeselect) in 212 subjects with a family history of colorectal cancer was assessed. RESULTS: Both Hemeselect and Haemoccult were positive in the only patient with colorectal cancer. Hemeselect was more sensitive than Haemoccult for adenomas (40% compared with 20%) (adenomas larger than 1 cm 75% compared with 50%). No additional abnormality was detected by the addition of Haemoccult or Hemeselect to 60 cm flexible sigmoidoscopy in screening people at lower levels of familial risk. A false positive rate of 16% for Hemeselect resulted in a high proportion of additional colonoscopies in this group. CONCLUSIONS: At present faecal occult blood tests are not sufficiently sensitive or specific to replace endoscopy in screening people at risk of familial colorectal cancer.

Adenoma↗
PubMed1997

Long-term results of the Angelchik prosthesis for gastro-oesophageal reflux.

INTRODUCTION: Between 1982 and 1989, 46 patients had insertion of an Angelchik prosthesis for gastro-oesophageal reflux. Eleven patients (24 per cent) subsequently had the prosthesis removed, all but one for intractable dysphagia. METHODS: Thirty-six of the original patients were followed by questionnaire, and 32 of these had a barium marshmallow swallow investigation. RESULTS: A high proportion of patients (20 of 26) with a prosthesis in situ had symptoms of dysphagia. On objective evaluation by marshmallow swallow, the transit time was significantly slower than that of an age-matched control group (P < 0.01), but showed no significant deterioration with time compared with previous postinsertion studies. CONCLUSION: The Angelchik prosthesis causes long-term dysphagia in a high proportion of patients, severe enough in one-quarter to necessitate its removal. Its continued use cannot, therefore, be recommended.

Adult↗
PubMed1997

Randomized trial of the addition of flexible sigmoidoscopy to faecal occult blood testing for colorectal neoplasia population screening.

BACKGROUND: Published data suggest that screening might reduce the mortality rate from colorectal neoplasia. Faecal occult blood (FOB) testing suffers from poor sensitivity and significant numbers of interval cancers, both of which should be improved by the addition of flexible sigmoidoscopy (FOS). METHODS: This prospective, randomized study aimed to assess the compliance and neoplasia yield of FOB testing and FOS compared with that of FOB testing alone. From general practitioner registers, 6371 asymptomatic patients (3124 men, 3247 women; age range 50-74 years) were invited for screening by means of FOB testing (3128 patients) performed at home, or a combination of FOB testing and FOS (3243 patients). RESULTS: Compliance with FOB testing alone was 50 per cent. In the FOB testing/FOS group, 48 per cent returned the FOB test but only 20 per cent went on to FOS. Despite the poor compliance, the neoplasia yield was four times greater in the FOB testing/FOS group. CONCLUSION: FOS increase the neoplasia yield but strategies to improve compliance must be identified for this to become a population screening test.

Aged↗
PubMed1996

Randomised controlled trial of faecal-occult-blood screening for colorectal cancer.

BACKGROUND: There is growing evidence that faecal-occult-blood (FOB) screening may reduce colorectal cancer (CRC) mortality, but this reduction in CRC mortality has not been shown in an unselected population-based randomised controlled trial. The aim of this study was to assess the effect of FOB screening on CRC mortality in such a setting. METHODS: Between February, 1981, and January, 1991, 152,850 people aged 45-74 years who lived in the Nottingham area of the UK were recruited to our study. Participants were randomly allocated FOB screening (76,466) or no screening (controls; 76,384). Controls were not told about the study and received no intervention. Screening-group participants were sent a Haemoccult FOB test kit with instructions from their family doctor. FOB tests were not rehydrated and dietary restrictions were imposed only for retesting borderline results. Individuals with negative FOB tests at the first screening, together with those who tested positive but in whom no neoplasia was found on colonoscopy, were invited to take part in further screening every 2 years. Screening was stopped in February, 1995, by which time screening-group participants had been offered FOB tests between three and six times. Screening-group participants who had a positive test were offered full colonoscopy. All participants were followed up until June, 1995. The primary outcome measure was CRC mortality. FINDINGS: Of the 152,850 individuals recruited to the study, 2599 could not be traced or had emigrated and were excluded from the analysis. Thus, there were 75,253 participants in the screening group and 74,998 controls. 44,838 (59.6%) screening-group participants completed at least one screening. 28,720 (38.2%) of these individuals completed all the FOB tests they were offered and 16,118 (21.4%) completed at least one screening but not all the tests they were offered. 30,415 (40.4%) did not complete any test. Of 893 cancers (20% stage A) diagnosed in screening-group participants (CRC incidence of 1.49 per 1000 person-years), 236 (26.4%) were detected by FOB screening, 249 (27.9%) presented after a negative FOB test or investigation, and 400 (44.8%) presented in non-responders. The incidence of cancer in the control group (856 cases, 11% stage A) was 1.44 per 1000 person-years. Median follow-up was 7.8 years (range 4.5-14.5). 360 people died from CRC in the screening group compared with 420 in the control group-a 15% reduction in cumulative CRC mortality in the screening group (odds ratio=0.85 [95%; CI 0.74-0.98], p = 0.026). INTERPRETATION: Our findings together with evidence from other trials suggest that consideration should be given to a national programme of FOB screening to reduce CRC mortality in the general population.

Adenoma↗
PubMed1996

Gastrimmune raises antibodies that neutralize amidated and glycine-extended gastrin-17 and inhibit the growth of colon cancer.

The effect of gastrin neutralization was evaluated on the in vivo growth of the rat colon line, DHDK12, which expressed cholecystokinin B/gastrin receptors and secreted glycine-extended gastrin-17 (G17). Gastrin neutralization was achieved by administration of the immunogen, Gastrimmune, which is composed of the amino terminal portion of G17 linked to a diphtheria toxoid. A rat-specific version of Gastrimmune was used to preimmunize rats, with control animals receiving diphtheria toxoid only. The antibodies raised neutralized both carboxy-amidated and glycine-extended G17. The tumor was implanted into the muscle layer of the abdominal wall, and rats immunized with Gastrimmune had significantly reduced median cross-sectional tumor areas (70.2% reduction; P = 0.005) and weights (56.5% reduction; P = 0.0078)) when compared to control rats. Histological analysis revealed that the tumors had an enhanced degree of necrosis, with the area of viable tumor in the Gastrimmune-immunized rat reduced to 40.3% compared to 58.6% in the control rats (P = 0.003). Immunization with Gastrimmune raised antibodies that inhibited the growth of a rat colon tumor. This could have been mediated by neutralization of both serum G17 and cell-associated precursor gastrin molecules.

Amino Acid Sequence↗
PubMed1996

Ki-ras mutations in adenomas: a characteristic of cancer-bearing colorectal mucosa.

Activating mutations in the Ki-ras2 oncogene are frequently observed in sporadic colorectal adenomas and their incidence is reported to rise in large and tubulovillous adenomas to values close to those in carcinomas. This study shows that this property is a feature of adenomas growing in large bowel that has already demonstrated its propensity to engender malignant tumours: i.e., bowel in which there is a synchronous carcinoma. Adenomas from cancer-free bowel do not share this high incidence of Ki-ras mutations. This difference in mutation incidence between adenomas from cancer-free and cancer-bearing patients does not appear to derive from sampling bias relative to adenoma size, site, or patient age, nor is it found in another gene (APC) known to be of importance in adenoma formation. Large, dysplastic adenomas from cancer-bearing bowel, however, are particularly liable to carry Ki-ras mutations when they arise in patients over 70 years old. The observations suggest that the role of Ki-ras mutations may be more subtle than merely enhancing adenoma growth. Adenoma cells of cancer-prone individuals may suffer more mutational events than those in persons selected as cancer-free.

Adenoma↗
PubMed1996

Screening for colorectal cancer with an immunological faecal occult blood test: 2-year follow-up.

This study is a 2-year follow-up of an average-risk population offered screening with both Haemoccult and Hemeselect tests to determine the interval cancer rate, and thus sensitivity. The effect on compliance with Hemeselect of testing over 1 day rather than 3 days was investigated in a separate cohort. In the first study, 3948 subjects received tests; 1489 (37.7 per cent) completed both tests and 148 had a positive result, 17 (1.1 per cent) were Haemoccult positive and 145 (9.7 per cent) were Hemeselect positive. Investigation of 142 patients revealed ten with cancer (Dukes stage A, seven; B, one; C, two). All were detected by Hemeselect but only one was Haemoccult positive. After a median follow-up of 35 (range 26-43) months, seven further patients developed colorectal cancer (stage A, one; B, three; C, three) but none followed a negative Hemeselect test (100 per cent sensitivity). In the second study 2703 subjects were offered Hemeselect tests. Compliance for testing over 1 day (48.6 per cent) was significantly better than that over 3 days (43.1 per cent) (chi 2 = 8.1, 1 d.f., P < 0.01). Hemeselect is a promising screening test for the early detection of colorectal cancer.

Aged↗
PubMed1996

Oestrogen and progesterone receptors in gastrointestinal cancer cell lines.

Expression of sex steroid receptors by gastrointestinal (GI) tumours may indicate a role for hormonal manipulation in their management. A panel of seven established cell lines derived from primary human GI tumours were assayed for oestrogen and progesterone receptor (ER and PgR) expression by ligand binding, immunocytochemistry and enzyme-immunoassay methods. It was possible to demonstrate very low levels of both ER and PgR in the GI cell lines using enzyme immunoassay (EIA), with levels of PgR generally higher than those for ER. Neither ER nor PgR were detected in cytosols made from the GI cell lines in a classical dextran coated charcoal ligand binding assay. Similarly, immunohistological analysis (Abbott ERICA, PgRICA) of cultured cell preparations or of frozen and paraffin sections of xenograft tumour failed to demonstrate receptors. This confirms that low PgR levels are measurable by EIA in GI tumour cell lines. Upregulation of PgR expression in tumours by exposure to oestradiol in vitro was not observed.

Animals↗
PubMed1996

Greater frequency of K-ras Val-12 mutation in colorectal cancer as detected with sensitive methods.

Assays for tumor mutations need to be sufficiently sensitive that a mutation can be readily detected in a high background of wild-type sequence. We have evaluated competitive allele-specific oligonucleotide (cASO) hybridization, the amplification refractory mutation system (ARMS), and a combination of cASO with mutant-enriched polymerase chain reaction (ME-PCR) for their respective sensitivities in detecting the K-ras Val-12 mutation. cASO hybridization detected 1 mutant allele in 100 wild-type alleles and identified 6 of 74 (8%) colorectal tumors as having the Val-12 mutation. ARMS detected 1 mutant in 1000 and 12 of 74 (16%) tumor samples, and the ME-PCR with cASO hybridization detected 1 in 5000 and 20 of 74 (27%) tumor samples. The mutation was not detected in normal bowel mucosa from selected Val-12 tumor-positive patients. ME-PCR combined with cASO resulted in a threefold higher detection rate than has previously been reported and suggests that other studies may have underestimated the frequency of K-ras mutations.

Base Sequence↗
PubMed1995

Effect of gastrointestinal hormones and synthetic analogues on the growth of pancreatic cancer.

The effects of hormones and synthetic analogues have been examined on the growth of 2 human pancreatic cancer cell lines, MiaPaCa2 a well-established cell line and PANI which was derived in our own laboratories from a tumour specimen. The hormones/growth factors included gastrin (G-17), epidermal growth factor (EGF) and bombesin, while the synthetic analogues used were a gastrin receptor antagonist (CR 1718), a somatostatin analogue (RC-160) and a bombesin receptor antagonist (ICI 216,140). Cell proliferation was assessed by the [75Se]selenomethionine uptake method which has been shown to correlate with cell counts. The effect of each hormone or growth factor on growth was expressed as a percentage of the untreated control. There were 5 replicates in each experiment, and each one was repeated at least 3 times. In vitro growth of both cell lines was unaffected by gastrin, bombesin or the respective antagonists (CR1718 and ICI 216140). The somatostatin analogue RC-160 also had no effect on basal growth. Significant growth stimulation of both MiaPaCa2 and PANI was seen with epidermal growth factor. We tested the hypothesis that somatostatin analogues may inhibit EGF-stimulated growth on both MiaPaCa2, a somatostatin receptor positive cell line, and on PANI which is negative for somatostatin receptors. RC-160 did not inhibit EGF-stimulated growth of either MiaPaCA2 or PANI. Both cell lines were established in vivo as xenografts in nude mice. The effect of RC-160 on tumour growth was measured. RC-160 inhibited the growth of MiaPaCa2, the somatostatin receptor-positive cell line, but not of PANI.

Adenocarcinoma↗
PubMed1995

Inhibition of organ invasion by the matrix metalloproteinase inhibitor batimastat (BB-94) in two human colon carcinoma metastasis models.

The effect of the matrix metalloproteinase inhibitor batimastat was evaluated in two human colorectal cancer metastasis models involving: (a) the liver-invasive tumor C170HM2 and (b) the lung-invasive tumor AP5LV, both of which have been shown to express the M(r) 72,000 type IV collagenase. Batimastat at concentrations between 0.01 and 3.0 micrograms/ml had no direct cytotoxic effects on the in vitro growth of the cell lines. In the liver-invasive tumor model, batimastat administered i.p. from day 10 to termination of the therapy (day 39) at 40 mg/kg reduced both the mean number of liver tumors (35% of vehicle-treated control; P < 0.05) and the cross-sectional area of the tumors (43% of vehicle-treated control; P < 0.05). In the lung-invasive tumor model, batimastat administered daily (40 mg/kg i.p.) significantly reduced tumor weight within the lung (72% of vehicle-treated control; P < 0.05) but did not significantly affect nodule number. In the latter model, in which the take rate was unaffected, tumor cells were introduced into the lateral tail vein, and lung localization may have been a physical phenomenon not involving invasion. In the former model, tumor cells were introduced directly into the peritoneal cavity, and from there the cells adhered to and invaded the liver capsule. Because the take rate is significantly reduced, it may be that the matrix metalloproteinases are involved in this process. Batimastat may be a therapeutic modality for the treatment of colorectal cancer metastasis.

Animals↗
PubMed1995

Five-year prospective study of DNA tumor ploidy and colorectal cancer survival.

BACKGROUND: Retrospective studies have suggested that DNA tumor content (ploidy) has a significant effect on survival. This group has reported, prospectively, that among patients who had colorectal resections for carcinoma, the 2-year tumor recurrence rate was significantly greater for patients with aneuploid tumor than for those with diploid tumors. This paper reports the 5-year survival rates of this cohort of patients. METHODS: Three hundred sixty-three patients who had colorectal resections for cancer between November, 1982, and March, 1988, were studied prospectively. The DNA tumor ploidy was measured from fresh and paraffin embedded tissues. These patients were followed regularly in a dedicated colorectal clinic for a minimum of 5 years or until death. Of the 363 patients studied, 2 were lost to follow-up. RESULTS: Forty percent of the tumors were diploid, the remainder aneuploid. The 5-year survival for patients who had curative resections was 76% for those with diploid tumors compared with 64% for aneuploid tumors (P = 0.05; Mantel-Cox, 3.7). On further analysis, the survival benefit conferred by a diploid tumor appeared to be confined to those with Stage B tumors. There was no relation between ploidy and sex, age of patient, stage, histologic grade, or site of tumor. CONCLUSIONS: Ploidy is a useful objective measurement of the aggressiveness of Stage B tumors. Patients with aneuploid Stage B tumors have a poor prognosis; this group may benefit from adjuvant therapy.

Adult↗