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Biomedical subjects

F A Macrae

Publications and source records attributed to F A Macrae.

At least 37 records · Page 2Linked to original sources

Impact of a hospital-based register on the management of familial adenomatous polyposis.

Colorectal cancer in familial adenomatous polyposis is a preventable disease in at-risk relatives of patients with primary cases. Until the recent establishment of a register in Western Australia, there has been no registration of pedigrees or central organization of surveillance in Australia. In the present study, the experience of 20 such families who were associated with The Royal Melbourne Hospital was documented, with an analysis of the reasons for any failure of management. The impact of a hospital-based register on the management of the disease was studied. In each family, results were categorized according to whether "at-risk" relatives had been diagnosed at surveillance examinations, and whether the Hospital register were involved. Before involvement with the register, 24 family members presented with symptomatic polyposis after the first affected case had been diagnosed. Eighteen of these had colorectal cancer at diagnosis, and 16 subjects now are dead. Identifiable reasons for the failure of surveillance were family communication failure (two cases), family denial (two cases), failure of the hospital clinic (two cases) and a failure to cover extended branches of families who were living locally (nine cases), interstate (four cases) or overseas (three cases). In contrast, only two (6%) of 33 affected cases that were identified at a planned surveillance endoscopy had colorectal cancer at diagnosis. Without the active surveillance of at-risk family members, lethal delays in diagnosis are likely to occur. Most reasons for failure potentially are correctable by a dedicated registry that is responsible for notifying clinicians and patients about the timing of surveillance procedures.

Adenomatous Polyposis Coli↗

Participation of healthy volunteers in research projects.

Research that involves healthy normal volunteers frequently is performed. This article examines ethical guide-lines for the recruitment of healthy volunteers in research projects. Ethical decisions on projects that are based on patient-volunteers or healthy normal volunteers should balance the risk to the volunteer and the collective benefit to the community. For healthy normal volunteers that risk should be minimal or trivial. Investigators should follow recruitment practices that avoid approaches to persons who are dependent upon them in some way, and should carry the day-to-day ethical responsibility even after institutional ethical approval has been granted. Pilot studies and self-experimentation readily can transgress ethical guide-lines. Compensation for mishaps or injuries that occur during research in which there is no question of negligence (for example, an unforeseeable reaction in a phase-1 drug trial) is an unresolved issue which should be addressed by the research community. It is recommended that action be taken to ensure that healthy volunteers who participate in approved research have redress in the rare event of an accident, whether this is a result of negligence, chance or misadventure. Hospitals/institutions or other bodies that sponsor research should extend their insurance to cover specifically such unforeseeable events in which there may be liability, and to have the facility for a payment of beneficence in the case of accidents in which liability cannot be established.

Australia↗

Chromosome studies in inherited nonpolyposis colon cancer syndrome.

This study was designed to determine if any constitutional chromosomal markers were linked with the expression of colorectal neoplasms in the inherited nonpolyposis colon cancer syndrome, using a number of cytogenetic techniques. High resolution G-banding in 12 affected and 17 unaffected family members did not reveal a structural chromosome abnormality. Increased C-band heteromorphism was not seen in either affected or unaffected individuals, and no heritable fragile sites were detected. Mean baseline and mitomycin C-induced sister chromatid exchanges were not elevated in affected patients compared with controls. Mapping of sister chromatid exchanges did not reveal any hot spots of exchange. A tumor cell line with the karyotype 46,XY,der(13),t(13;?)(p11;?) was established from one patient, but no constitutional abnormality of chromosome #13 was found. In addition, 11 patients with familial polyposis coli were studied with high resolution G-banding and no heteromorphism of chromosome #2 in the region 2q21.3 was detected.

Cell Line↗

Factors affecting compliance in colorectal cancer screening. Results of a study performed in Ballarat.

Non-compliance in screening programmes for colorectal cancer is likely to be the most important factor limiting the impact of screening on mortality. This study aimed to determine risk factors and correlates of compliance that could be readily identified by general practitioners. A total of 581 eligible subjects aged 40 to 75 years completed a questionnaire that covered demographic factors, personal medical history, family history of colorectal cancer and smoking status. Faecal occult blood tests were then offered by the general practitioner and compliance correlated with responses. The over-all compliance was 44% and increased to 51% for those who accepted the self-testing kit at consultation. For men, compliance increased with increasing level of education and was significantly greater for non-smokers than for smokers. For women, compliance increased with increasing age, and was greater for those with either symptoms and/or a family history of colorectal cancer. A doctor group-practice factor appeared to influence acceptance versus refusal of the test kit from the doctor. A triage approach to screening in general practice may improve over-all compliance and the yield of tumours. With this strategy, patients at high risk (for example, those with a family history of colorectal cancer or in older age groups) are identified first. Particular attention should be given during consultation to those at high risk who have poor compliance profiles (for example male smokers with a family history of colorectal cancer). High-risk subjects with high compliance profiles would need less attention and low-risk individuals would need least attention.

Adult↗

Therapeutic benefits from a poorly absorbed prednisolone enema in distal colitis.

A double blind controlled trial has been conducted in 40 patients to compare the therapeutic effects of prednisolone metasulphobenzoate enemas with those of prednisolone-21-phosphate enemas. Both enemas brought about improvement in symptoms and sigmoidoscopic appearances in more than 70% of patients treated. The absorption of prednisolone from the metasulphobenzoate enema in three patients was less than from the 21-phosphate enema. In view of the low plasma prednisolone concentrations obtained, there are theoretical advantages in using a poorly absorbed enema to avoid the possibility of systemic steroid effects in patients requiring long term steroid treatment.

Adult↗

A colon cancer cell line (LIM1215) derived from a patient with inherited nonpolyposis colorectal cancer.

A new human colon cancer cell line (LIM1215) has been derived from a tumor arising in a member of a family known to have a high incidence of colorectal cancer. The tumor cell line is comprised of small pleomorphic cells that clone in liquid medium and form tumors in immunosuppressed mice. Ultrastructurally, the cells are capable of differentiation, with cells with multiple microvilli and cells resembling goblet cells being present in the one culture. The cells are pseudodiploid and contain a 13p+ marker chromosome.

Adenocarcinoma↗

Predicting colon cancer screening behavior from health beliefs.

A total of 581 people (33% male, 67% female) attending general practitioners completed a questionnaire mainly on health beliefs and were then offered a fecal occult blood test (Hemoccult II) free of charge. Eighty-six percent accepted the general practitioners' offer and took the Hemoccult kit home. Of these, 51% complied (i.e., returned specimens for laboratory testing). The Health Belief Model was found to account for 12% of the variance in screening behavior. Perceived barriers to taking the test and perceived susceptibility to bowel cancer were the only components contributing significantly in the multiple regression analysis. Health Belief Model components that were predictive of initial acceptance of the test offer differed from components predictive of ultimate compliance. The influence upon compliance of family history of colorectal cancer, history of colonic symptoms, smoking habits, perceived attitudes of spouses, attitude to detection tests, and subjective stress related to the threat of bowel cancer were also investigated.

Adult↗

Histopathology and prognosis of malignant colorectal polyps treated by endoscopic polypectomy.

The histopathological features and results of treatment of malignant polyps removed by endoscopic polypectomy from 60 patients are presented. The patients were followed for a minimum of five years. Forty six patients were treated by polypectomy alone as local excision was judged complete and the invasive carcinoma was well or moderately well differentiated. Thirty seven of these patients are alive and well after five years and the remaining nine have died of other causes up to four years later: there was no evidence of recurrence in any of these cases. Fourteen patients underwent a subsequent major surgical resection and residual tumour was found at the site of polypectomy in two cases but regional lymph nodes were not involved. Only one patient from this group with a high grade tumour developed metastases although the operative specimen was free of tumour. Malignant polyps can be successfully treated by polypectomy alone provided both the laboratory techniques of examination and the histopathological criteria are strictly applied.

Adenoma↗

Self-reported dark red bleeding as a marker comparable with occult blood testing in screening for large bowel neoplasms.

The study was designed to determine the prevalence of large bowel symptoms in an adult working population and to assess their value in screening for large bowel neoplasms. A symptom questionnaire was sent to workers in two large organizations and the results were compared with faecal occult blood testing in the same individuals using Haemoccult (Eaton Laboratories). Completed symptom questionnaires and Haemoccult test kits were returned by 916 out of a total of 1805 employees over the age of 40 (compliance 50.7 per cent). Twenty-eight (3.1 per cent) were Haemoccult positive and 114 (12.4 per cent) had one or more symptoms. All positives (129 persons) were examined by flexible sigmoidoscopy and barium enema. No cancer was found but 7 patients with adenomas greater than 10 mm diameter were discovered. Each of the 7 patients reported at least one symptom (dark red bleeding in 4, bright red bleeding in 2 and diarrhoea in 1) and 6 were Haemoccult positive. There was no individual with a Haemoccult positive adenoma without symptoms. Predictive values for adenomas over 10 mm for Haemoccult positive tests (21 per cent), self-reported dark bleeding (16 per cent) and diarrhoea (17 per cent), were significantly higher than for other symptoms. The predictive value rose significantly to 46 per cent for Haemoccult-positive patients who in addition had at least one symptom (P less than 0.05) and to 57 per cent for Haemoccult positive with dark bleeding. These combinations of Haemoccult- and symptom-positive results increased the specificity of 97.6 per cent for Haemoccult alone to values over 99 per cent without reducing sensitivity.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenoma↗

Towards safer colonoscopy: a report on the complications of 5000 diagnostic or therapeutic colonoscopies.

The diagnostic and therapeutic benefits of colonoscopy are well known but most large-scale surveys, especially those involving multiple centres, may underestimate the range and incidence of complications. The detailed records of 5000 colonoscopies in a specialist unit have been analysed and conclusions drawn which may help to make the procedure safer. The incidence of haemorrhage was 1% and bowel perforation 0.1%. All the major haemorrhages occurred during polypectomies over 2 cm in size. Secondary haemorrhage was an unpredictable occurrence, one to 14 days later. Three deaths followed colonoscopy: one cardiorespiratory death was related to oversedation; a second was due to mismanaged ischaemic colitis developing two days after traumatic instrumentation, and the third was due to peritonitis. Minor complications included thrombophlebitis, abdominal distension, and vasovagal episodes. Because of experience during the first half of the series and also due to improvements in instrumentation, the complication rate of the later part of the series was halved. Recommendations include the avoidance of oversedation, review of previous barium enema films so as to be aware of large polyps which are more likely to bleed, and the recognition of situations where perforation or septicaemia is likely to occur.

Adult↗

Neoplasia and ureterosigmoidostomy: a colonoscopy survey.

Patients who have undergone implantation of ureters into the sigmoid colon (ureterosigmoidostomy) are known to be at high risk of developing cancer of the colon many years later. The operation is often performed in infancy for congenital abnormalities of the bladder, thus creating a long term surveillance problem. Six of 34 patients (17.6 per cent) who had undergone ureterosigmoidostomy were found at a screening fibresigmoidoscopy to have adenomas of the left colon or severe dysplasia of the stoma, a mean interval of 22 years after their urinary diversion. Four other patients had previously had a sigmoid adenoma or cancer; thus, 29 per cent overall had developed colonic neoplasms, almost all closely related to their stomas. Another patient who, by error, was excluded from the surveillance, died of metastatic cancer of the sigmoid colon within the study period. Regular surveillance by fibresigmoidoscopy of patients who have had urinary diversion affords the opportunity to detect and remove potentially malignant sigmoid lesions. In addition to its clinical importance, it allows a closer study of this unique model of colon carcinogenesis.

Adenoma↗

A prospective study of diagnostic methods in adenoma follow-up.

Three hundred and thirty patients having had previous colonoscopic polypectomy of adenomas were recalled for follow-up and submitted to all available diagnostic methods: occult blood testing, digital examination, rigid proctosigmoidoscopy, fibre-optic sigmoidoscopy, total colonoscopy and double contrast barium enema. Polyps up to 7 mm diameter were electro-coagulated during diagnostic endoscopy but larger polyps were left in situ for barium enema before polypectomy at a later date. Disparities between endoscopy and X-ray were rechecked by one or both procedures. Occult blood testing, digital examination and rigid proctosigmoidoscopy were found to be inaccurate or ineffective in diagnosis of the 37% of patients with further adenomas or carcinomas. Double contrast barium enema demonstrated 71% of larger lesions compared to the 92% shown by colonoscopy. The commonest sites of X-ray inaccuracy were in the sigmoid colon and caecum. Colonoscopy permits immediate electrocoagulation or snare polypectomy of any lesions seen, as well as being the more accurate investigation and is, therefore, the procedure of choice in post polypectomy follow-up. The mean time taken for diagnostic total colonoscopy in this series was 15.3 minutes, comparable to the time taken for barium enema. Postal questionnaire showed both procedures to be equally well tolerated by the patients. Thirty per cent of colonoscopies were, however, considered technically difficult by the endoscopist, and for these patients it is suggested that follow-up should be by the combination of fibre-sigmoidoscopy using carbon dioxide insufflation and immediate double contrast barium enema. Should this combination indicate a need for total colonoscopy, then almost all adenomas and cancers would be detected. Total examination of the colon by one or other means is essential, over half the patients with adenomas and three of the five patients with carcinoma showing no pathology in the territory of fibresigmoidoscopy or limited colonoscopy.

Adenoma↗