Moisture content of Hemoccult slides influences test sensitivity

BACKGROUND: Mass screening programmes in Europe and in the USA have shown that a 15-18% decrease in mortality rate from colo-rectal cancer can be achieved with biannual testing. In a 10 year screening programme in the Isère region (France), we have noticed that the positivity percentage of Hemoccult II changes significantly with seasons: it varies from 1.61% in summer to 2.80% in winter, while intermediate values occur in spring (1.69%) and autumn (2.50%). During transport in the mail, Hemoccult slides are stored in unheated rooms, without air-conditioning, and are thus being exposed to outdoor conditions of temperature and humidity. In this paper, we show that the moisture content of Hemoccult slides influences test sensitivity. METHODS: In an in-vitro experiment, we smeared slides from the same batch all with the same blood-spiked stool sample. Positivity rate varies from 58%, when slides contain 0.46% moisture, to 84% when they contain 10.90% moisture (P = 0.0066). Positivity rates are not different in rehydrated and in saturated Hemoccult slides. RESULTS: Data collected from the Grenoble meteorological centre were compared to positivity percentages. Regression studies show that moisture deficit in the air is strongly correlated (r = 0.794, P < 0.01) to positivity percentage and explains most of its seasonal variations. CONCLUSIONS: These results would suggest that Hemoccult slides should be allowed to equilibrate for 24 h at the same level of moisture in all seasons at least in regions where large temperature variations are observed between winter and summer, and between day and night. Indeed, positivity percentages are probably too high in winter, and too low in summer.     

Incidence and mortality trends for prostate cancer in 5 French areas from 1982 to 1996.

After an increase in the 1980s, incidence and mortality for prostate cancer in North America or England and Wales started to decrease in the early 1990s. The reasons for this evolution are widely debated, notably the importance of early detection. This study describes trends of prostate cancer incidence and mortality in 5 areas in France, where practices of early detection for this cancer are widely used. The 5 French administrative areas, covered by a population-based registry, have a total population of approximately 1,700,000 men. Incidence data from these registries were studied for the period 1982-1995, and mortality data were provided by the Institut National de la Santé et de la Recherche Médicale (INSERM) for the period 1982-1996. Age-Period-Cohort models by Poisson regression were created to characterize these trends. Between 1982 and 1995, 14,699 cases of prostate cancer were registered by the 5 registries under consideration. After a little intensification of the increase in 1987, undoubtedly due to early detection (notably using Prostate-Specific Antigen), the trend of the incidence seems to reverse from 1993. Mortality increased monotonically from 1982-1990 by an average of 1.8% per year, before decreasing annually by an average of 3.3% until 1996. Poisson regressions indicated a period effect on both incidence and mortality data; a small, but significant, cohort effect exists for incidence evolution, showing that elements such as etiologic factors may have an influence. Until results of randomized studies on mass screening are available, the question of individual screening remains; improved knowledge of risk factors could be interesting.     

Colonoscopy practices, and colorectal cancer and polyp screening, as assessed in the French district of Isère from May to July in 2004

Background

A pilot program of organized screening for colorectal cancers was conducted in Isère, an administrative district in France. A fecal occult blood test (Hemoccult II^®) was proposed for all individuals aged greater than 50 years (women since 1991 and men since 2002), followed by colonoscopy for those testing positive. A prospective study was carried out from May to July in 2004 and compared with a similar study conducted in 1996. The goal was to investigate colonoscopy practices, especially the role of screening.

Methods

Gastroenterologists practising in Isère (n = 39/42 practitioners) completed a questionnaire including their patients’ age and gender, indications, methods and results for all colonoscopies performed in those aged greater than 20 years. Any tissue samples taken were sent away for histological evaluation.

Results

The study involved 2558 colonoscopies (54% female, 73% patients aged greater or equal to 50 years), an increase of 35% from 1996 to 2004. Of the patients referred, 50.0% were symptomatic (pain; bowel problems: 28.7%; rectal bleeding: 21.3%), 23.5% had colonic disease and 22.5% came from screening (3.1% had positive stool tests, 17.8% had a family history). Recommendations related to family history (update of the 1998 consensus conference: screening indicated for patients with a first-degree relative diagnosed with cancer or advanced polyps aged less than 60 years) were well applied in terms of relatedness (81%) but, in 52% of cases, the age was greater than 60 years. Colonoscopy was carried out in almost all cases (0.1% failure), with complications in 0.4% of the examinations. Of the 2558 colonoscopies performed, 10% revealed advanced polyps or cancer: 30% were following a positive test compared with 8% for symptoms and 6% with a family history. Multivariate analyses showed that polyps greater or equal to 10 mm or malignant tumors are 1.5 times more common in men than in women, and six times more frequently seen in patients having colonoscopy following a positive test for blood in stools than in those with a family history of colorectal cancer. The number of pathologies found increased significantly in those aged greater than 50 years.

Conclusion

This cross-sectional survey of colonoscopy practices in Isère shows an increase in the number of colonoscopies performed between 1996 and 2004. This increase is not explained by expansion of the screening program, which was the reason for only 3% of colonoscopies. However, the best diagnostic yield for advanced polyps or cancers was obtained in screened patients (30%).     

Influence of gamma-irradiation sterilization on the structural defects of sapphire single crystals (alpha-Al(2)O(3))

The influence of sterilization by gamma rays on the structure and the electrical behaviour of sapphire single crystal (alpha-Al(2)O(3)) was studied successively by thermoluminescence, by cathodoluminescence and by observation of the scanning electron microscope mirror effect. The mirror method allowed us to measure the capacity of an insulating material to trap electrons. The structural analysis of the alpha-Al(2)O(3) showed that there were oxygen vacancies, as well as chromium and titanium impurities. It was possible to demonstrate that these defects, especially the oxygen vacancies, are in a different state after a 30 kilogray irradiation. The valency state changes of these defects and the presence of trapped charges are accompanied by a deformation of the crystalline lattice which results in a modification of its electrical properties. At room temperature, the irradiated alpha-Al(2)O(3), unlike non irradiated alpha-Al(2)O(3), is capable of trapping electrons. It can be concluded that gamma-ray sterilization modifies the cohesive energy of alpha-Al(2)O(3), which could lead to mechanical changes (surface charge, friction, wear, fracture strength, em leader) in this material.     

Incidence of colonic and rectal tumors as a function of the urban and rural characteristics of the residential area in the Isère district (1979-1985), France

From 1979 to 1985, 1443 new malignant tumors of the colon and 1017 of the rectum appear in the departement of Isère (France). Using the urban category of "Zone de Peuplement Industriel et Urbain" (Z.P.I.U), we were able to classify place of residence within 3 strata, according to the proportion of inhabitants of the rural (or urban) type. For both sexes, incidence of colon carcinomas is higher in urban categories than in rural ones. For males, incidence of rectal carcinomas is higher within areas of the rural type. Going from the urban category of the rural one, "urban" being the level of reference. Relative Risks for men are 1,0.9 and 0.6 for the colon, and 1, 1.3 and 1.2 for the rectum. For women, RR's are 1,0.8, and 0.7 for colon, and 1,1.0, and 0.8 for the rectum. Same results are described in the literature, with higher risks for colon cancers in urban areas. Our results reporting lower incidence for rectal carcinomas in Isère among men, are in contradiction with other results in the literature. This work supports the idea that epidemiology of large bowel carcinomas should focus onto segments. Second, when categories of residence allow it, it is worthwhile looking at gradients that bring more information on the relation, than the simple dichotomy: urban versus rural.     

Synaptic and non-synaptic AMPA receptors permeable to calcium.

For a long time, alpha-amino-3-hydroxy-5-methyl-4-isoxazole-propionate (AMPA) receptors permeable to calcium have been considered to be either non-existent or as "atypical". There is now ample evidence that these receptors exist in numerous regions of the nervous system and in many neuronal as well as non-neuronal cell populations. This evidence has been accumulated by several methods, including electrophysiological recording, calcium imaging and cobalt-loading. Functional AMPA receptors permeable to calcium are already expressed at very early stages of embryonic development, well before the onset of synaptogenesis. They are probably involved in the paracrine signaling necessary for construction of the nervous system before becoming involved in synaptic transmission. In immature cells, cyclothiazide strongly increases the steady-state level of responses not only to AMPA, but also to kainate. Ingestion, during pregnancy, of food or drug substances that can cross the placental barrier and act upon the embryonic receptors may constitute a risk for normal development. In the adult nervous system, synaptic as well as non-synaptic (paracrine) AMPA receptors permeable to calcium are probably widely expressed in both glial and neuronal cells. They may also participate in controlling some aspects related to adult neurogenesis, in particular the migration of newly formed neurons.     

Hyperhomocysteinemia and myocardial remodeling in the sand rat,Psammomys obesus

ObjectiveNumerous studies have shown that a methionine-rich diet induces hyperhomocysteinemia (Hhcy), a risk factor for cardiovascular diseases. The objective of the present study was to determine the involvement of Hhcy in cardiac remodeling in the sand rat Psammomys obesus.Materials and methodsAn experimental Hhcy was induced, in the sand rat Psammomys obesus, by intraperitoneal injection of 300 mg/kg of body weight/day of methionine for 1 month. The impact of Hhcy on the cellular and matricial structures of the myocardium was analyzed with histological techniques (Masson trichrome and Sirius red staining). Immunohistochemistry allowed us to analyze several factors involved in myocardial remodeling, such as fibrillar collagen I and III, metalloproteases (MMP-2 and -9) and their inhibitors (TIMP-1 and -2), TGF-β1 and activated caspase 3.ResultsOur results show that Hhcy induced by an excess of methionine causes, in the myocardium of Psammomys obesus, a significant accumulation of fibrillar collagens I and III at the interstitial and perivascular scales, indicating the appearance of fibrosis, which is associated with an immuno-expression increase of TGF-β1, MMP-9 and TIMP-2 and an immuno-expression decrease of MMP-2 and TIMP-1. Also, Hhcy induces apoptosis of some cardiomyocytes and cardiac fibroblasts by increasing of activated caspase 3 expression. These results highlight a remodeling of cardiac tissue in hyperhomocysteinemic Psammomys obesus.