Sample bias and overinference: two sources of error in interpreting case report data.
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Müllerian inclusions in peritoneal washings from female patients may be mistaken for adenocarcinoma. Such findings were studied in the peritoneal washing cytology specimens from eight cases. The inclusions usually presented as tubular or papillary structures, often forming a single layer of epithelium surrounding psammoma bodies. The cells forming these structures often displayed some degree of atypia. Recognition of this entity in peritoneal fluids is important to avoid a misdiagnosis of disseminated cancer. A general outline is proposed for interpreting such findings in peritoneal washings, based on the cytomorphology of these structures as well as the microscopic features of the primary neoplasms.
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The authors used radiopaque vascular casts to test a new computer-based analysis method that employs a densitometric profile to determine arterial diameters. Results from this method were compared with those obtained with caliper measurements of overhead projection images of the radiograph and direct caliper measurements of the vascular cast. In addition, the corresponding in vivo angiograms were compared with the measurements obtained from the vascular casts. Vessel diameters obtained from cast radiographs by caliper measurement, operator-determined and automated densitometric curve fitting showed excellent correlations with acceptable intraobserver and interobserver variation. All methods, however, underestimated arterial diameters by about 7% compared with diameters obtained from casts by direct caliper measurements. In vivo angiograms revealed smaller arterial diameters than those obtained from specimens. However, we observed higher correlations for measurements at stenotic sites than in non-stenotic regions. Our results suggest definite limitations for the often used direct comparison between in vivo angiographic and postmortem findings.
Posterior enhancement beyond liver hemangiomas was retrospectively assessed on 89 hemangiomas of all size and localization with in the liver. This enhancement is seen only beyond big and complex lesions, containing hypoechoic or anechoic zones. Conversely, it seems to be very rare beyond little hyperechoic lesions. It is necessary to distinguish true enhancement and a mirror artefact beyond lesions of all sizes but localized just near the diaphragma. In the lesions of less than 2 cm, no clear posterior enhancement was discovered, but some of them showed a very clear mirror artifact.
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Sonograms often contain distortions and ghosts that may result in misinterpretations. The present work deals with some common artifacts and explains the reasons behind them. It is generally impossible to eliminate these effects, but if they are known, and if the equipment is used correctly and the examiner has sufficient experience of scanning, misdiagnoses can generally be avoided.
The observation that protein-A conjugated gold sols bound to fibronectin-collagen (FNC) fibres in human fibroblast cultures prompted a series of studies on the binding of gold particles stabilized in various ways (Staphylococcal protein A, bovine serum albumin, avidin, streptavidin, gelatin, hemoglobin, polyethylene glycol (MW 20 000), methylcellulose and the nonionic detergent Tween 20) to cell and tissue components, to protein dot blots and SDS-PAGE blots on nitrocellulose paper. We found that binding of gold particles to certain cell and tissue components and to various immobilized proteins did occur irrespective of the stabilizing agent. We argue that, albeit gold sols are stabilized against salt coagulation by adsorption of proteins and other stabilizing agents, "naked areas" are (constantly or intermittently) present on particle surfaces, available for interaction with cell and tissue components that have a high electrostatic affinity for the charged gold surface under prevailing experimental conditions. Non-specific binding may be reduced or abolished by competing proteins (i.e. proteins with a higher affinity for gold than any component in the object studied) provided the proteins and the gold conjugate are present concomitantly during incubation. We found gelatin (Bloom number 60-100) to be an effective competitive protein probably due to its high affinity for gold over a wide pH range. Further, gelatin did not appreciably inhibit the specific interaction in dot blots between SpA and IgG except at very low IgG concentrations. A protocol for the use of gold-protein conjugates to circumvent the hazards of unspecific gold binding is suggested.
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The cervical mass screening programme in the GDR (since 1973) indicates a high degree of participation exhibiting a sufficient specificity. The sensitivity however has to become better. The main cause of false negative diagnoses is the insufficient gaining materials from the endocerrix channel. This may be corrected by a new plastic spatula. Both the consequent education of the prescreeners and collective final diagnoses may give further help to reduce cytological false negative diagnoses. False positive diagnoses are less fatal. They may be corrected by repeated controls, by special consultations, and by histology.
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