Search

Background. Participation by the target population is clearly a key element in the success of mass screening programs for colorectal cancer. In France, involvement of general practitioners in test distribution is essential to reach a satisfactory participation rate, but other forms of recruitment also have to be organized. The aim of this study was to determine the influence of demographic characteristics such as sex, age, and place of residence on the participation rate in a French mass screening according to different recruitment methods. Methods. The Hemoccult IIR test was proposed in three consecutive ways: spontaneously by general practitioners and occupational doctors during appointments (phase 1), by postal invitation (phase 2), and finally by direct mailing of the test (phase 3). The target population consisted of 11,947 people between 45 and 74 years of age, living in a district of the French county of Calvados, between March 1991 and April 1993. Results. The overall participation rate was 51.3%. Forty-nine percent of all the tests were done during phase 1, 31% during phase 2, and 20% during phase 3. The overall participation rate varied essentially according to the place of residence, from 65.5% in urban areas and 48.9% in intermediate areas to 27.7% in rural areas. The overall participation rate was also higher for females (57%) than for males (45%) and for those 60 years and older (53.9%) than for those below this age (49.2%). The proportion of tests done during phase 1 was lowest among the youngest and the oldest age groups (37.5% in the 45- to 49-year class and 45.2% in the 70- to 74-year class) and among people living in the rural environment (respectively 55.3%, 45.5%, and 35.9% in urban, intermediate, and rural areas). Conclusions. This study shows that place of residence strongly influences the global participation rate in mass screening for colorectal cancer in France, whereas sex and age have little influence. Recruitment methods complementary to distribution by general practitioners must be organized, especially for the youngest and oldest age groups (45-49 years and 70-74 years) and above all for people living in rural areas. The social, cultural, and. psychological reasons for these differences remain to be investigated, with the aim of adapting mass screening strategies to the different population groups.Copyright 1995, 1999 Academic Press, Inc.

From isoactivity curves (showing activity as a function of pH and ionic strength) it was found that in the pH domain 6.7–8.6 frequently used in experiments involving hen lysozyme, the pH optimum of lysis of Micrococcus luteus ceils at low ionic strength (0.02–0.05) by the high-temperature form (40°C physiological temperature) was one to two pH units lower than that by the low-temperature form (20°C).

The previously described temperature and pH-dependent transition in the solid state of hen lysozyme was studied in solution. Experiment concerning the velocity of lysis ofM. luteus by lysozyme and its behavior in presence of an inhibitor (GlcNAc) as well as a reinvestigation of the Arrhenius curves over a large range of pH, demonstrated the existence of two temperature-induced domains. An inhibitor-insensitive lysozyme form was characterized at 40° (physiological temperature).

Despite encouraging results from recent studies, there is still no consensus to undertake mass screening using the Haemoccult test in the general population. The success of mass screening for colorectal cancer depends among other things on Haemoccult test properties. In on-going screening programmes, the Haemoccult test consists of six slides and a test is considered positive if at least one slide is coloured. The aim of this work was to study the influence of the type and number of positive slides on the Haemoccult test's positive predictive value and characteristics of screened lesions. This work focuses on 63,958 first tests in a mass screening programme in Calvados (France) among people aged 45-74 years. There was a linear relation between the positive predictive value for cancer or an adenoma larger than 1 cm and the number of positive slides (P < 10(-4)). The positive predictive value for cancer or large adenoma was significantly higher when 4-6 slides were positive (44.3%) than when only 1-3 were positive (19.1%) (P < 10(-4)). In this latter group, the subjects in whom tumours were detected were younger and had significantly less extensive cancers. Borderline tests (no slides positive and at least one slide with a blue coloration confined to the edges) had a positive predictive value for cancer or an adenoma larger than 1 cm no different to that of tests with 1-3 positive slides. Subjects with borderline results were markedly younger than the others and had less extensive cancers and rectal localisation more often than the others. Our results suggest that (1) increasing the number of positive slides required to declare a test positive leads to an increase in the positive predictive value but is not to be recommended because of the sensitivity of the test and (2) considering borderline Haemoccult tests as positive in on-going and future mass screening campaigns would allow an increase in the sensitivity of the test, especially for rectal cancer and low extensive tumours without any decrease in its positive predictive value.

Le dépôt de résidus des fabrications d'uranium et de thorium qui ont eu lieu sur le site du Bouchet (Essonne) de 1949 à 1970 est une des composantes du système de traitement et de rejet des déchets de l'usine. Au cours des opérations de démantèlement et d'assainissement de cette ancienne usine de la Direction des productions du CEA1, la majeure partie des matières et matériels contaminés par des uranium et thorium ont été évacués (période de 1970-1979). Il subsiste deux zones occupant 1 ha : un bassin de décantation et une zone de dépôt pour les résidus solides. Les niveaux de flux d'émission radon avant la réhabilitation du site étaient 10 à 100 fois supérieurs à la moyenne des flux de radon à la surface de la terre (104atome m-2s-1) et les concentrations en descendants à vie courte du radon 222 étaient, dans l'environnement immédiat du site, supérieurs d'environ 20 % aux niveaux prescrits en 1991 par un arrêté du préfet de l'Essonne. Les différentes mesures de radioactivité réalisées sur le site, ou dans son environnement proche, mettent en évidence l'efficacité de la réhabilitation réalisée en 1992-1993, les niveaux en concentration des descendants à vie courte du radon étant du même ordre de grandeur que ceux rencontrés dans le Bassin parisien.

From isoactivity curves (showing activity as a function of pH and ionic strength) it was found that in the pH domain 6.7–8.6 frequently used in experiments involving hen lysozyme, the pH optimum of lysis ofMicrococcus luteus ceils at low ionic strength (0.02–0.05) by the high-temperature form (40°C physiological temperature) was one to two pH units lower than that by the low-temperature form (20°C).

The physicochemical characterization of the solid-state enantiomers and racemate of efaroxan hydrochloride (C13H17N2O+Cl-, M=252.5 g mol-1) was performed by thermoanalytical methods (differential scanning calorimetry, thermogravimetry and thermomicroscopy) and spectral methods (infrared spectrometry and X-ray diffractometry). The efaroxan enantiomers and racemate were shown to be unstable near the melting point. At the beginning of the decomposition, a loss of hydrogen chloride was observed. However when sealed pans were used, the compounds decomposed at higher temperature, allowing a precise evaluation of the melting enthalpies by means of differential scanning calorimetry. The nature of the racemate and its thermal stability were assessed by evaluating its free formation enthalpy. An enantiotropic solid-solid transformation (II→I) was noted for the racemate; the reverse process (I→II) follows zero-order kinetics.

The phase diagram of R(+)-S(-) efaroxan hydrochloride (Tfus.(R)=245.1±0.3°C. ΔHfus.(R)=119.6±3.0 J g-1) shows a racemic compound. The melting temperature and melting enthalpy of the compound are: Tfus.(RS)=247.8±0.2°C and ΔHfus.(RS)=124.6±2.4 J g-1. A solid ↔ solid transformation takes place at Ttrs.=180±1°C, ΔHtrs.=15.0±0.4 J g-1. This transition is observed between 3 and 97% R(+). The stability of the racemic compound already established in a previous study was confirmed by the value of Petterson's coefficient (i=1.19). The two eutectic positions at 20 and 80% R(+) that define the range over which the racemic compound is found, exclude the use of resolution methods by preferential crystallization.

We have shown that efaxoran hydrochloride and efaxoran hydrobromide form solid solution over the entire range of compositions. The small values of enthalpy of mixing indicate that the system is close to ideality. Consequently, Oonk's method was used for its modelling, assuming that the liquid phase is ideal and the departure of the solid phase from ideality was expressed by the excess free enthalpy gE. The results obtained agreed with experience.

The gene nm23-H1 (Steeg, JNCI, 80, 1988) has been considered as a tumour suppresor gene implicated in metastatic spread. In some murine and human tumours, as breast cancer, its expression is linked to a low metastatic potential and a better prognostic. We have studied the nm23-H1 protein expression and the clinical agresivity of 62 cases of colorectal cancer that had been treated with radical surgery. Expression of nm23-H1 was determined by inmunohistochemical methods, using the monoclonal antibody NCL-nm23-2. Of the 62 cases studied, 25 (40%) expressed the protein (nm23 +) and 37 (60%) did not (nm23 -). We analized the correlation between the presence or the absence of nm23 and some known clinical and hystological prognostic factors and the relapse probability, the disease free survival (DFS), and the overall survival (OS), No statistical differences were observed between the two groups in relation to lymph nodes afectation, hystological grade and CEA serum level. With a follow-up between 6 and 10years, there were no differences in relapse appearance. DFS and OS were significantly better for nm23 - patients. 31% of the nm23 + patients and 70% of nm23 - patients were free of disease at 5years with 26% and 52% at 10years (p<0.04), OS was 29% for nm23 - patients and 75% for nm23 + patients at 5 years and 24% and 54% at 10years (p<0.01). These results shows worse prognosis for those patients with nm23-H1 protein expression, against what was expected because of the suppression function that has been described for such gene. This study is being continued in order to confirm these results.