[Effects of phytohemagglutinins on rat mesenteric mast cells].
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Biomedical subjects
Publications and source records attributed to M Crespi.
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Several unresolved issues still cast doubts on the epidemiological data which point to an association between infection from Helicobacter pylori (Hp) and gastric cancer. These are: a) the male/female ratio of gastric cancer ranges from 4 to 1.5 in all studies, whereas the prevalence of Hp infection is the same in both sexes; b) the prevalence of Hp infection is as high as 90% in several developing countries where the frequency of gastric cancer is very low; c) the acquisition of the infection at a young age, considered very important with regard to the risk for cancer, varies from 4.2% to 83% in several countries in which the mortality for stomach cancer is, on the average, 10/100,000; d) the incidence of cancer in patients with a duodenal ulcer is half of that of the general population but Hp infects up to 100% of these patients. In the sequence of events that lead to gastric cancer, Hp appears to play a role only in the very initial steps, as a causative agent of chronic inflammation. The further events which lead to cancer are multifactorial, involving environmental agents and the host response. It is therefore inappropriate to consider Hp a direct carcinogen for humans. This also applies to specific strains of the bacterium such as the ones expressing the cagA gene. In a study we conducted in an area with a low incidence of gastric cancer (Latina), the prevalence of Hp infection was equal to 78.6% and, among the positives, 81% resulted cagA positive. This data, if compared with a similar research that took place in another area with a high incidence of gastric cancer (San Marino) where the prevalence of Hp infection was 51% and cagA 69%, further demonstrates the inconsistency of associating Hp and cancer of the stomach.
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Colorectal cancer is one of the most frequent neoplasms in Western countries with an estimated 400,000 deaths per year worldwide. Several randomized studies have demonstrated that screening programs with FOBT (Fecal Occult Blood Test) reduce mortality from 18 to 33%, whereas case-control and cohort studies with endoscopy have shown a mortality reduction ranging from 60 to 76%. The target population for secondary prevention is men and women aged more than 50 years and younger subjects in case first-degree relatives are affected or the family pedigree raises the suspicion of a genetic syndrome. This report summarizes the results of different screening strategies for average risk patients (FOBT, anamnestic risk questionnaire, sigmoidoscopy, colonoscopy and virtual colonoscopy) and the surveillance protocols applicable to high-risk patients, particularly for hereditary syndromes such as HNPCC and FAP.
An epidemiologic survey among 538 young persons between 15 and 26 years of age in a high-risk area for esophageal cancer in the People's Republic of China revealed a high prevalence of esophagitis. Histologically confirmed very mild, mild, and moderate esophagitis was observed in 31.6%, 10.7%, and 1.1% of 354 male and 30.4%, 4.3%, and 1.1% of 184 female subjects. The prevalence of micronuclei in esophageal smears was assayed in a subsample to investigate its possible association with esophagitis and with risk factors for esophageal lesions. Of the 186 subjects, 2.7% had mild or moderate esophagitis, 19.9% had very mild esophagitis, and 77.4% were normal. The frequency distribution of micronucleated cells in the esophageal mucosa was similar for the three diagnostic groups. Mean percentages of micronucleated cells did not differ by diagnosis of esophagitis, household status, current smoking status, presence of oral leukoplakia, or consumption of burning hot beverages or fresh fruit. Higher mean percentages were observed in the older age group of both sexes, but the difference was not statistically significant. The results suggest that if esophagitis is considered an important precursor state in the development of esophageal cancer, the scoring of micronuclei does not appear to be an efficient test for mild forms of esophagitis.
In the present report we have analyzed data reported in literature on the diagnostic accuracy of endoscopy and associated sampling techniques compared to standard and double contrast radiological examinations, as well as the rate of malignant transformation of benign gastric ulcer. Data on 117 patients with benign gastric ulcer examined in our Center between 1974 and 1984 are reported. From our experience, we may state that only one case underwent to malignant transformation, i.e. a rate of 1.2%, in agreement with recent literature. Three cases of malignant-ulcer had gone undiagnosed at first endoscopy, but were correctly diagnosed at a short-term re-examination. The present study, other than reconfirming the importance of the endoscopic examination with associated techniques, stresses the importance of aimed cytology and of short-term endoscopic re-examination as a mean for lowering the rate of false negative diagnoses.
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