Model building on the basis of Dutch cervical cancer screening data

A mass screening programme for cervical cancer is in progress in three pilot regions in The Netherlands. All women living in these regions aged 35-53 are invited to undergo screening at three-year intervals. The MISCAN simulation model was developed for the analysis and optimization of screening programmes. In this paper the model-based approach to evaluation is first outlined and then illustrated by analysing data from the first two screening rounds in the pilot regions. This analysis resulted in a rather restricted range of data-compatible assumptions for the mean duration of preclinical disease (14-19 yr) and the frequency of spontaneous regression of preinvasive lesions (45-65%), as well as a rather wide sensitivity range for the Pap smear (50-90%). These preliminary findings are compared with those of a previous MISCAN analysis of cervical cancer screening in British Columbia. On the basis of an assumed 18-yr duration, 50% regression and 70% sensitivity, a number of screening policies relating to the same age ranges but with different intervals are compared. Both the analysis and the policy comparisons are preliminary, but the findings are nevertheless reasonable and consistent with those of previous studies. A more complete MISCAN-based analysis of the Dutch screening programme and subsequent optimization of screening policies will be possible when further results become available and a cost-effectiveness analysis procedure has been incorporated into the MISCAN programme.     

Interaction of biodegradable β-whitlockite ceramics with bone tissue: An in vivo study

The biodegradation of different porous β-whitlockite materials are studied by in vivo experiments, radiographie follow-ups and light microscopy observations. The materials were implanted in rabbit tibiae for 16 mnth. Micropores play an important role in the biodegradation rate. The resorbing materials evoke an inflammation with plasma cells. The resorption starts in the medulla, and the phagocytosed particles are removed to the lymph nodes. Normal bone function can be restored after all the implant material is resulted.     

Association of vitamin D receptor gene polymorphisms with insulin resistance and response to vitamin D

The objectives of the study were to determine associations between single nucleotide polymorphisms (SNPs) of the vitamin D receptor (VDR) gene and insulin resistance and the effects of these SNPs on changes in insulin sensitivity in response to vitamin D supplementation. The research described here was an extension of the Surya study. Genotyping of the Cdx-2, FokI, BsmI, ApaI, and TaqI SNPs was carried out on 239 South Asian women in New Zealand using polymerase chain reaction-based techniques. Associations of these genotypes and 3' end haplotypes with insulin resistance were determined using multiple regression analysis. Associations between SNP genotypes and responses in insulin sensitivity to vitamin D supplementation (4000 IU vitamin D(3) per day) were also determined for a subset (81) of these women. BsmI BB, ApaI AA, and TaqI tt genotypes were significantly associated with lower insulin resistance compared with BsmI bb, ApaI aa, and TaqI TT, respectively, in the cohort of 239 women. Furthermore, homozygosity of the haplotypes baT and BAt was associated with higher and lower insulin resistance, respectively, compared with no copies of their respective alleles. Of the 81 subjects who were supplemented with vitamin D, women with the FokI Ff genotype showed a significantly greater improvement in insulin sensitivity (increase of 29.4 [2.9, 38.1]) compared with women with the FokI FF genotype (increase of 2.3 [-11.5, 10.1]). This study has highlighted the association of vitamin D responsiveness and insulin resistance with VDR gene polymorphisms. This is the first study to determine associations between all three. Genotyping of the VDR gene may provide a predictive measure for insulin resistance in response to vitamin D intervention.     

Fungal flora in groundwater-derived public drinking water

In order to assess the dissemination of hygienically relevant fungi via the public drinking water distribution system, a 12-month survey was performed on groundwater-derived drinking water from 29 water supplies in North Rhine-Westphalia, Germany. Frequencies of contaminated water samples, and the prevalent species and patterns of occurrence in raw water, waterworks, the network and house installations were studied on the basis of 2657 water samples. Results were obtained by long-term incubation of 1 ml aliquots of water samples on agar-based culture media, following bacteriological procedures documented in the German drinking water regulations (Anon, 1990). No correlation with standard hygiene indicators, such as E. coli or other coliform bacteria was observed. Common opportunistic and allergenic Aspergillus species were encountered only rarely. The fungal flora was dominated by a limited number of species of Acremonium, Exophiala, Penicillium and particularly Phialophora; some of them occurred throughout the entire drinking water system and are thought to constitute a resident fungal flora. Phialophora sp. nov., to be described as a new species elsewhere, was ubiquitous; it was found in 26.6% of the samples positive for fungi (7.5% of 2657). Fungal diversity in the network itself was significantly lower than in raw water and house installations, indicating that not all fungi gaining access to the system are capable of surviving for longer periods. For species such as Verticillium lecanii, found exclusively after the introduction of newly buried pipes and remaining localized at those sites, introduction via arthropod vectors is likely. The resident species of Phialophora, Exophiala and Acremonium are particularly significant as they are shown to be disseminated efficiently by public drinking water.