Comparison between a guaiac and three immunochemical faecal occult blood tests in screening for colorectal cancer.

BACKGROUND: The aim of this study was to compare the performance of the guaiac-based faecal occult blood test (G-FOBT), with that of three immunochemical faecal occult blood tests (I-FOBT) which allow automatic interpretation. PATIENTS AND METHODS: Under the French organised screening programme, 85,149 average-risk individuals aged 50-74 participating in the third screening round, performed both the G-FOBT (Hemoccult-II test) and one of the I-FOBTs: FOB-Gold, Magstream and OC-Sensor. RESULTS: Given the chosen threshold, the positivity ratio between the different I-FOBTs and the G-FOBT was 2.4 for FOB-Gold, 2.0 for Magstream and 2.2 for OC-Sensor (P=0.17). The three I-FOBTs were superior to the G-FOBT for colorectal cancer (CRC) detection. The ratios for detection rates were 1.6 (FOB-Gold), 1.7 (Magstream) and 2.1 (OC-Sensor) (P=0.74). For non-invasive CRC they were, respectively, 2.5, 3.0 and 4.0 (P=0.83) and for advanced adenomas 3.6, 3.1 and 4.0 (P=0.39). CONCLUSIONS: This study provides further evidence that I-FOBT is superior to G-FOBT. None of the three I-FOBTs studied appeared to be significantly better than the others.

Comparison of a guaiac and an immunochemical faecal occult blood test for the detection of colonic lesions according to lesion type and location.

We investigated variations in sensitivity of an immunochemical (I-FOBT) and a guaiac (G-FOBT) faecal occult blood test according to type and location of lesions in an average-risk 50- to 74-year-old population. Screening for colorectal cancer by both non-rehydrated Haemoccult II G-FOBT and Magstream I-FOBT was proposed to a sample of 20 322 subjects. Of the 1615 subjects with at least one positive test, colonoscopy results were available for 1277. A total of 43 invasive cancers and 270 high-risk adenomas were detected. The gain in sensitivity associated with the I-FOBT was calculated using the ratio of sensitivities (RSN) according to type and location of lesions, and amount of bleeding. The gain in sensitivity by using I-FOBT increased from invasive cancers (RSN=1.48 (1.16-4.59)) to high-risk adenomas (RSN=3.32 (2.70-4.07)), and was inversely related to the amount of bleeding. Among cancers, the gain in sensitivity was confined to rectal cancer (RSN=2.09 (1.36-3.20)) and concerned good prognosis cancers, because they involve less bleeding. Among high-risk adenomas, the gain in sensitivity was similar whatever the location. This study suggests that the gain in sensitivity by using an I-FOBT instead of a G-FOBT greatly depends on the location of lesions and the amount of bleeding. Concerning cancer, the gain seems to be confined to rectal cancer.

Two successive hepatitis C virus infections in an intravenous drug user.

We report the case of an occasional intravenous drug user who developed two successive hepatitis C virus (HCV) infections. The first infection led to seroconversion (anti-HCV antibodies detected) and the detection of HCV RNA in serum. After a spontaneous recovery (normalization of alanine aminotransferase levels and HCV RNA clearance), a second HCV infection was observed, with the recurrence of HCV viremia. Antibody directed against HCV serotype 1 was detected throughout the follow-up monitoring, but two different HCV strains were identified during the two infectious episodes: genotype 1a for the first and genotype 3a for the second. This observation shows that primary HCV infection does not confer protective immunity against subsequent infection with viruses of other genotypes. This may hamper the development of a vaccine. Conflicting results were obtained in genotyping and serotyping assays, suggesting that the serotyping method cannot be used to identify the HCV type in patients, such as intravenous drug users, who are exposed to successive HCV infections.

[The Pneumococcus Observatory of the Central Region, from June 1, 1997 to May 31, 1998]. / Observatoire du pneumocoque de la région Centre, du 1er juin 1997 au 31 mai 1998.

714 pneumococcus were listed from 14 laboratories between the 1 June 1997 and the 31 May 1998. Data capture was done on Epi info software and concerned age, file number, consultation/hospitalization, sample type, susceptibility to oxacilline (5 micrograms), the results of the E-test for penicillin G, amoxicillin, cefotaxime and the results of the routine disk diffusion susceptibility method. Strains with reduced susceptibility to penicillin G (PRSP) were collected by the coordinating center to perform MICs by the reference method of agar dilution and serotyping. Over 714 strains, 45.7% of the samples originated from lungs, followed by 22% for blood samples, 14% for ear pus and 2.3% for CSF. 34% of the patients were female. 36.7% were children under 16 (57.8% PRSP) and 63.3% were adults (41% PRSP). 338 strains (47.3%) were determined as PRSP and 293 of them were studied by the coordinating center. 81 of the 293 PRSP (27.7%) were resistant et 212 (72.3%) were intermediate to penicillin G. 81% of the PRSP studied had a CMI value for penicillin G within +/- 1 log2 dilution. 20 strains of PRSP were resistant for amoxicillin (6.8% of the PRSP) and two (0.7% of the PRSP) for cefotaxime. 289 serotyping were done, most met serotypes were 23 (25%), 14 (23%). The least met was 15 (2.4%). These results let assess the epidemiology of pneumococcus in our region.

[Magnetic resonance imaging: early detection of involvement of the central nervous system in acquired immunodeficiency syndrome]. / Imagerie par résonance magnétique: dépistage précoce des atteintes du système nerveux central au cours du syndrome d'immuno-déficience acquise (SIDA).

Central Nervous System (CNS) involvement, whether primary by the Human Immunodeficiency Virus--HIV--itself, or secondary (toxoplasmosis or lymphoma) is remarkably frequent in AIDS, in 40 to 70% of cases, depending upon the author. In order to study the natural history of this illness, a cohort of 25 asymptomatic seropositive patients have been established. Every 6 months these patients undergo biological and clinical examinations, as well as Magnetic Resonance brain scans. After two examinations at a 6 month's interval, the first results are reported. Out of these 25 cases, 9 present anomalies: One patient with diffuse cerebral atrophy and 8 others with high signal intensity areas on T2 weighted sequences, like those of the Multiple Sclerosis. No relationship could be demonstrated between the existence of these lesions and various criteria such as age, sex, risk factors and T4 cells count. The nature of these lesions is not clear. They certainly indicate early involvement of the CNS after primary infection by the HIV virus. They may either represent scars of the primary infection or early alterations announcing developing encephalopathy.

[Comparison of the mean-term physiological effects of cis or trans docosenoic acids in the rat. I. Digestibility of fatty acids. Effects on growth, organ weights and heart histology]. / Etude comparée des effets physiologiques a moyen terme des acides cis et trans docosénoiques chez le rat. I. Utilisation digestive des acides gras. Effets sur la croissance, le poids des organes, et l'histologie du coeur.

The mean-term physiological effects of brassidic acid (n-9, trans docosenoic acid) and of erucic acid (n-9, cis docosenoic acid) have been compared to those of their C 18 homologues, elaidic and oleic acid, in a 2(3) factorial experiment; the 3 tested factors are: 1) the chain length of the dietary monoenes (C 22:1 vs. C 18:1), 2) the geometrical configuration of their double bond (trans vs. cis) and 3) the dietary level of linoleic acid (30% vs. 1,7% of dietary fatty acids). Wistar weanling rats have been fed for 16 weeks semi-synthetic diets containing 15% of lipids by weight, in which the fatty acids under study (brassidic, erucic elaidic) ranged to 40%. Although caution has been taken to optimize the digestibility of brassidic acid (interesterification of the lipid mixture, reduced level of calcium in the diet, addition of monoglycerides), it remains lower that of erucic acid. However, because of different levels of food consumption, the absorbed amounts of the two isomers are about the same. With a high dietary supply of linoleic acid, the dietary monoenes (C 22:1 or C 18:1), cis or trans) do not induce great changes in the weight gain of the rats, when adjusted to food consumption; linoleic acid subdeficiency lowers this adjusted weight gain, except when the diet contains oleic acid as the only monoene. These effects do not parallel those observed on the absolute growth of the rats. The trans monoenes, and to a lesser extent, erucic acid, induce an increase of liver weight (adjusted to body weight). The light microscopic histological study of the heart does not reveal any difference between the brassidic acid fed-rats and those fed the C 18:1 monoenes (elaidic, oleic). In contrast, erucic acid induces definite lesions of the myocardium. The dietary level of linoleic acid has little influence on the incidence and the severity of the lesions. The effects of these dietary fatty acids on the lipid contents and fatty acid compositions of different organs will be reported in a second paper.