Regions, networks and fluids: Anaemia and social topology.

This is a paper about the topological presuppositions that frame the performance of social similarity and difference. It argues that 'the social' does not exist as a single spatial type, but rather performs itself in a recursive and topologically heterogeneous manner. Using material drawn from a study of the way in which tropical doctors handle anaemia, it explores three different social topologies.

Principles and practices of medicine. The co-existence of various anemias.

The medical textbooks in our university library present 'principles' as the basis which underlies medical 'practice'. In this article it is argued that this helps different medical logics to co-exist. The example analyzed is that of anemia in the Netherlands.

Radiopacity of posterior composite resins, composite resin luting cements, and glass ionomer lining cements.

The radiopacities of seven posterior composite resins, seven composite resin luting cements, and six glass ionomer lining cements were studied. The purpose was to obtain an indication of radiopacity values of different brands within each of these three groups of materials and to show differences in radiopacities of composite resin inlay materials and their accompanying luting cements. On radiographs, the optical densities of standardized samples were determined and radiopacity values of the materials were expressed in millimeter equivalent aluminum.

Locating the periapical region in dental radiographs using digital image analysis.

An algorithm was designed to automatically obtain information on the orientation of roots in dental radiographs aimed at localizing the periapical region. A curve was approximated mathematically by a cubic polynomial to intersect the boundary of the root at its apex. The performance was judged by comparing the location of this intersection with the actual location of the apex as determined by five expert observers.

Application of computer-aided image interpretation to the diagnosis of periapical bone lesions.

An image analysis system was developed for the computer-aided diagnosis of periapical bone lesions in dental radiographs. The system was designed to (1) identify the periapical region, (2) determine the presence of a periapical lesion and (3) estimate the size of the lesion in cases when a lesion had been found. To initiate the procedure, an observer indicates an arbitrary point on the root in a digitized radiograph.

The dependence of shrinkage stress reduction on porosity concentration in thin resin layers.

The development of polymerization contraction stress was determined as a function of the surface area of porosity, so that the contribution of voids in resin composite to stress relief could be investigated. Experiments were carried out on 200-microns-thick layers of resin bonded from wall to wall in a restrained condition. The resin samples were divided into three groups: Group A was without porosity, group B contained a small number of pores, and group C contained a large number of pores in comparison with group B.

Diagnosing periapical bone lesions on radiographs by means of texture analysis.

Trabecular pattern, the radiographic projection of trabecular bone, is a repeated structure that appears in a dental radiograph. Texture analysis, the computer image analysis of repeated patterns, is a technique that can be used to automate the diagnosis of periapical lesions with the detection of the absence of the texture that corresponds to the trabecular bone. The purpose of this study was to determine whether it is feasible to use texture analysis to identify the presence of the trabecular pattern in radiographs and to detect a periapical bone lesion based on a local absence of this pattern.

Application of digital image analysis in dental radiography for the description of periapical bone lesions: a preliminary study.

This paper describes an application of digital image analysis for the description of periapical bone lesion in dental radiography. These techniques enable the problem of observer variability to be circumvented, and can eventually be used for the quantitative assessment of bone lesions. Since periapical bone lesions appear radiographically as dark areas compared with their surrounding tissues, an edge-detection method was developed to extract the boundaries between anatomy and pathology.

Recombinant human erythropoietin increases blood pressure, platelet aggregability and platelet free calcium mobilisation in uraemic children: a possible link?

Recombinant human erythropoietin was administered to 10 uraemic children on chronic haemodialysis, all of whom responded by correcting their haemoglobin. In addition, they showed an increase in blood pressure; platelet aggregations, subnormal before therapy, improved during treatment. The intracellular free calcium concentration in platelets after thrombin stimulation also increased significantly during erythropoietin administration.

Enzymatic erythrocyte creatine determinations as an index for cell age.

Creatine concentration in red blood cells was determined after ammoniumsulfate precipitation on a clear hemoglobin-free filtrate with a new enzymatic assay making use of bacterial creatinase. The method described is more specific than Griffiths' method and can easily be mechanised and adapted for use in a routine laboratory using classical automated equipment. By contrast with Griffiths' method no significant interferences of amino acids and creatine-like molecules were found.

Mass concentration and activity concentration of creatine kinase isoenzyme MB compared in serum after acute myocardial infarction.

We compared three current methods (immunoinhibition, "Isomune-CK" immunoprecipitation, and the Tandem-E CKMB II immunoenzymometric assay) for determination of creatine kinase (CK; EC 2.7.3.

[Quality of dental radiographs. A sample from 52 general practices].

To assess the quality of dental radiographs in general practice, 1000 radiographs in 52 practices were collected and evaluated. The radiographs were judged by two examiners using standard series of X-ray film, showing different degrees of the nine different types of errors studied. Furthermore, the diagnostic quality was assessed; if the diagnostic value was poor, the cause was registered.

Digital image analysis for the diagnosis of periapical bone lesions: a preliminary study.

Digital image analysis techniques enable the problem of examiner variability to be circumvented, and can be used to develop quantitative descriptions of bone lesions. This study investigated a method for describing periapical bone lesions. An edge-detection technique was developed for application to routine periapical radiographs.

Absence of significant autosomal lesions in Huntington's disease.

Peripheral blood from six patients with Huntington's disease (HD) and six controls were cultured in three types of media known to produce fragile sites. A total of 3000 metaphases per group were scrutinized in a blind coded study. No significantly specific 'hot-spot' was found capable of differentiating between HD patients and controls.

Characterization of two simian virus 40-specific RNA molecules from infected BS-C-1 cells.

Two discrete simian virus 40 (SV40) RNA species sedimenting at 19 and 16S, respectively, that are present in infected BS-C-1 cells were characterized with respect to the base composition and the ribonuclease T1 fingerprints. The base composition of the 19S SV40 RNA was found to be cytidylic acid (C), 23.0; adenylic acid (A), 28.