An experimental inter-expert telepathology network using static imaging.

AIMS: To set up a network for remote consultation using static imaging telepathology via Internet connection between pathologists in different European countries, and to collect some numerical and subjective impressions on the usefulness of this form of telepathology. METHODS: A static image remote consultation network between 11 pathologists in nine European countries was set up; all pathologists were equipped with the same telepathology system. The pathologists formed three subject oriented subgroups concerned with prostate, melanoma, and soft tissue sarcoma pathology. Each pathologist sent and received a small number of cases, and data on each case were collected and analysed. The whole experiment was controlled through a World Wide Web site. RESULTS: A total of 56 case consultations on 34 different cases were exchanged. The average case document contained seven images, and contained 1.97 Mbytes of data. For cases in which data were recorded, average case preparation and remote consultation time was 55 minutes and 9.2 minutes, respectively. Transmission times averaged 3.9 minutes. In subjective impressions, reservations were expressed in several cases regarding the confidence that could be given to the diagnosis from the images presented. CONCLUSIONS: Remote consultation by telepathology via the Internet is now technically feasible and reasonably user friendly, but is only suitable as a method of disease diagnosis in some cases.

A prospective clinical evaluation of electronically mixed polyvinyl siloxane impression materials: results from the prosthetic "SuperStudy"--a consumer evaluation.

Polyvinyl siloxane (PVS) impression materials incorporating a polyether carbosilane wetting agent and mixed with an electronic mixing system (Pentamix) were clinically compared with traditionally delivered (i.e., automixed) PVS impression materials during routine use by 1,505 general and specialized dental practitioners evaluating more than 30,000 impressions. Each study participant selected 20 patients and used standard tooth-preparation procedures appropriate to the therapy required, supplied specific data on each case, and ultimately evaluated the marginal detail, fit, and success of the final restorations. The areas requiring evaluation upon completion of the final restorations were ranked between "excellent," "good," "poor," and "remake needed," among users of the PVS materials with the electronic mixing system. About 80% of the respondents rated the Pentamix system as easier to mix and deliver than the gun or hand-mixed systems and two thirds said it was faster to mix. The system also received high scores for hygienic delivery, ease of mixing, and clean-up.

Relocation accuracy on HOME computerized microscopes.

A major practical advantage of the HOME (highly optimized microscope environment) computerized microscope is the facility for relocating cells or other microscopic objects. Features can be marked directly on the microscope image using a mouse-driven cursor, and an interactive finder can then be used to relocate the marked features. Tests on a prototype HOME microscope have shown that positions can be relocated with an accuracy of standard deviation (SD) < 7 microm. The marked features could also be relocated on a second HOME microscope, although with somewhat reduced accuracy (standard deviations of < 17 microm). The system provides a very user-friendly environment for tasks requiring relocation of microscopic objects.

A new approach to man-machine communication for computerized microscopy.

HOME is a new computerized microscope designed to assist pathologists and cytotechnicians in routine examinations. The HOME workstation is composed of a standard light microscope fitted with objective and stage encoders, and a built-in high resolution computer display which superimposes dialog, drawing, and messages onto the optical microscope image. The software runs under Windows 3.x and provides interactive facilities such as accurate localization and relocation of zones of interest, morphometric measurements, patient data access, and quality control processes.

Nuclear DNA content and morphometric characteristics of normal, premalignant and malignant oral smears.

Three methods of DNA content assessment providing both rare-event and population features were applied to forty eight Feulgen-stained oral smears collected from twenty patients. The smears were collected from three sites and diagnosed either clinically as normal, or histologically as premalignant or malignant. Cell morphometry features were also measured from Papanicolaou-stained smears from each site. The three methods of DNA content assessment could distinguish clearly between normal and abnormal smears, but not between premalignant and malignant smears within the abnormal group. However discrimination could be obtained between these subgroups using cytoplasmic area. The results therefore suggest that a combination of DNA content and morphometric measurement of oral smears can give a useful method for detecting and localising premalignant and malignant conditions.

HOME: highly optimized microscope environment.

The Highly Optimized Microscope Environment (HOME) is a computerized microscope designed to assist pathologists and cytotechnicians in clinical routine tasks. The prototype system consists of a IBM-PC compatible computer and a light microscope in which a built-in high-resolution computer display image is superimposed on the optical image of the specimen. Also, a manually operated encoding stage and objective turret encoder are used to provide continuous monitoring of the stage coordinates and microscope magnification to the computer. This allows any position on a slide to be uniquely defined and makes it possible to measure interactively lengths and areas larger than the size of the microscope field. Software, written in the C language and operating under the MS-DOS/MS-Windows environment, is controlled by means of a mouse-driven cursor moving over menu light-buttons displayed on the microscope image. The HOME microscope workstation is potentially useful in a wide range of applications such as i) tagging information on particular cells and tissue structures that can thus be accurately located and relocated, ii) performing morphometric measurement, differential counting, and stereological assessment of biological specimens, and iii) training and educating laboratory personnel. Finally, HOME will offer in the near future a user-friendly interface for automatic image processing of cells and tissue entities in interactively selected specimen areas.

Automation in cervical cytology: an overview.

Cancer of the uterine cervix is one of the more common female cancers and a major source of premature female mortality. UK deaths in 1987 exceeded 2000. To reduce these rates, national screening programmes have been introduced using the Papanicolaou method. In screening for cancer, the examination of specimens is an intensive and expensive task. Its high cost has led to a number of attempts to automate the process, either fully or partially. Over the last 30 years, various experimental prescreening systems have been developed for the diagnosis of cytological samples including the use of image processing techniques. This paper presents a historical overview of automation in cervical cytology and the status of current developments for automated cytological diagnosis.

Analysis of rare high-DNA cell populations in serous effusions using continuous-motion imaging.

The rare high-DNA cell sub-populations in a series of serous effusion specimens were analysed to determine whether such measurements could provide a basis for the improved diagnosis of malignancy. Monolayer specimens stained with gallocyanin chrome-alum were scanned with the CERVIFIP continuous-motion image analyser to locate and measure the highest-DNA cells in the sample. Two types of features were obtained for the detected sub-populations; firstly, 'percentile ploidy' values which characterise the ploidy levels above which specified proportions of the total cells are found; and secondly 'percentage abnormal' values which characterise the proportion of the cells diagnosed as malignant during examination by a cytopathologist. The classification accuracy for one or both of these features was then obtained by comparison with the clinical outcome of each patient. The results gave a classification error of 9/44 (20%) using the 0.01% percentile ploidy alone, 6/44 (14%) using the 75% percentage abnormal feature alone, but only 2/44 (5%) from a box discriminant using both features. It was therefore concluded that the analysis of the high-DNA cell population could be of value in the diagnosis of malignancy in serous effusion specimens.

Response variability as a predictor of skin temperature biofeedback performance.

The purpose of the present study was to compare the power of three subject variables as predictors of performance in a skin temperature biofeedback task. Data from three related experiments (N = 52) designed to train digital skin temperature increases in four sessions were pooled. Three measures (mean skin temperature, standard deviation and standard error of estimate), derived from a prefeedback instructional control session, were correlated with three criteria derived from training sessions (temperature change in the first, last and mean of training sessions). There were significant correlations with standard error of estimate, the largest with the mean change measure, accounting for 14% of temperature variance. The findings are consistent with an operant conditioning model of biofeedback learning, and have implications for more optimal training methods and experimental designs based on assessment of the standard error of estimate.

Interval-coded texture features for artifact rejection in automated cervical cytology.

In order to improve the separation between abnormal cells and noncellular artifacts in the CERVIFIP automated cervical cytology prescreening system, 22 different object texture features were investigated. The features were all statistical parameters of the pixel density histograms or one-dimensional filtered values of central and border regions of the object images. The features were calculated for 231 images (100 cells and 131 artifacts) detected as Suspect Cells by the current CERVIFIP and were then tested in hierarchical and linear discriminant classifiers. After selecting the two best features for use in a hierarchical classifier, 83% correct classification was achieved. One of these features was specifically designed to remove poorly focused objects. With maximum likelihood discrimination using all 22 features, an overall correct classification rate of 90% was obtained.

The alveolar type II epithelial cell: a multifunctional pneumocyte.

The epithelial surface of the alveoli is composed of alveolar type I and type II cells. Alveolar type I cells comprise 96% of the alveolar surface area. These cells are extremely thin, thus, minimizing diffusion distance between the alveolar air space and pulmonary capillary blood. Type II cells are spherical pneumocytes which comprise only 4% of the alveolar surface area, yet they constitute 60% of alveolar epithelial cells and 10-15% of all lung cells. Four major functions have been attributed to alveolar type II cells: (1) synthesis and secretion of surfactant; (2) xenobiotic metabolism; (3) transepithelial movement of water; and (4) regeneration of the alveolar epithelium following lung injury. Therefore, alveolar type II cells play important roles in normal pulmonary function and in the response of the lung to toxic compounds which may cause lung damage. Techniques have now been developed to isolate and purify alveolar type II epithelial cells from lung tissue. Such cellular preparations afford bioassay systems to monitor the effects of occupational or environmental pollutants on alveolar pneumocytes and should yield important information concerning the etiology of pulmonary disease in the alveolar region of the lung.

Skin temperature biofeedback for multiple sessions with monetary incentives.

This study evaluated the relative effectiveness of two incentive contingencies in learning biofeedback-assisted control of peripheral skin temperature: positive versus positive/negative monetary incentives. Both incentive groups of 10 participated in six sessions, including pre- and posttraining voluntary control sessions, and four intervening sessions with visual feedback and monetary contingencies. Each session consisted of adaptation, resting baseline, feedback or voluntary control, and a final resting baseline. The results indicated no significant difference in response control between groups and an over-all decline in temperature within sessions. Self-control was evidenced by the slower rate of decline in temperature for the first as compared to the last session, and feedback control by the attenuation in the rate of decline in the last three training sessions. Based on data from other physiological responses, these findings are not likely due to habituation effects. It was concluded that response control should not necessarily be defined in terms of increasing temperature but rather by reference to an appropriate comparison condition. Motivational effects should be further investigated with alternative incentive contingencies.

Automated densitometry of cell populations in a continuous-motion imaging cell scanner.

Continuous-motion imaging provides a method for the rapid quantitative analysis of slide-mounted cell preparations. Densitometric and morphometric cellular features can be measured and used to classify individual cells. Tests on the densitometric accuracy of the CERVIFIP CMI system show a c.v. of 6.5% for diploid mouse hepatocytes and a measuring rate of up to 500 cells/sec. CMI is particularly useful for problems requiring the interactive analysis of rare cell types and for the measurement of morphological and densitometric characteristics of cell populations. Typical applications include the prescreening of cervical cytology specimens and the detection of rare autoradiographically labeled lymphocytes.

The use of cationic polyelectrolytes in the preparation of cell monolayers for automated cell scanning and diagnostic cytopathology.

The introduction of cationic polyelectrolytes as cellular adherents has significantly advanced the preparation of cervical scrape specimens for automated cell scanning and has also provided an efficient technique for the preparation of cell monolayers of other cytologic specimens, e.g., breast cyst fluids, urines and serous effusions, for diagnostic cytopathology. Variable thickness of cell preparation and cell overlap have both been resolved by laying cells onto glass slides coated with the cationic polyelectrolyte poly-L-lysine. We have determined the optimal conditions for pH, molecular weight, concentration and temperature for the application of poly-L-lysine as a cell-to-slide adhesive.

An automated image analysis system for the detection of rare autoradiographically labelled cells in the human lymphocyte HGPRT variant assay.

This paper describes a fast and accurate method for the identification of autoradiographically labelled human hypoxanthine-guanine phosphoribosyl transferase (HGPRT) variant lymphocytes on slide preparations using a high-speed computer image analysis system--the Fast Interval Processor (FIP). The system has been developed primarily for the analysis of cultured human peripheral blood lymphocyte populations in which the frequency of labelled cells may vary from less than one to more than 2,000 in every 10,000 cells. Evaluation experiments have demonstrated the excellent performance of FIP in the counting of labelled and total cells over this frequency range.

Basic performance tests on the CERVIFIP linear array prescreener.

CERVIFIP is a computer image-analysis prescreener for cervical cytology specimens. It is based on the Fast Interval Processor (FIP), a high-speed image analyzer, which uses a linear, charge-coupled, photodiode array scanner and a hardwired image data preprocessor unit for image data reduction prior to input to a computer. The software for CERVIFIP carries out real-time measurements and hierarchic classification of cells based on nuclear DNA content, morphologic and densitometric features for artifact rejection and operator review of cells suspected of being atypical. Preliminary tests have shown that the system is capable of accurate measurement of integrated optical density and positional information on cells at rates in excess of 30,000 cells per minute.

Pulmonary response to Mount St. Helens' volcanic ash.

The pulmonary response to a sedimented sample of Mount St. Helens' volcanic ash from the first eruption was studied at 1, 7, 28, 90, and 180 days postintratracheal administration of 1 or 10 mg of ash in specific-pathogen-free rats. One day administration of volcanic ash all animals exhibited a marked inflammatory cell response centered on respiratory bronchioles in which polymorphonuclear leukocytes predominated. At 7 days the reaction was characterized by mononuclear cellular infiltrates. The macrophages within the respiratory bronchioles and alveoli contained intracytoplasmic ash particles. At 28 days the intraalveolar aggregates of mononuclear cells had condensed to form granulomas. Most of the granulomas contained foreign body-type giant cells and some showed central necrosis. The granulomas enlarged in size from 28 days until the termination of the experiment at 180 days with progressive increase in the amount of collagenous tissue. The results of these studies suggest that the volcanic ash may pose a risk for pneumoconiosis in heavily exposed human populations.

Pneumoconiosis and lung function in a group of kaolin workers.

In June 1981, 65 current and former workers at a kaolin mine and mill were examined by chest radiography, spirometry, and a questionnaire. Five (13%) of 39 current workers and 3 (19%) of 16 former workers with 5 yr or more of exposure had radiographic evidence of pneumoconiosis. Among the 8 workers with pneumoconiosis, conglomerate upper lobe lesions were present in one half. No pneumoconiosis was observed among 8 current workers with less than 5 yr of exposure. Lung function testing showed significant reductions (p less than 0.05) in FVC, FEV1, and peak flow rate in kaolin workers compared with that in a control group. Environmental sampling during the testing period showed airborne dust to be composed of kaolinite (96%) and titanium dioxide (4%). Additional controlled epidemiologic studies among kaolin workers are needed to generate reliable prevalence data for pneumoconiosis and to assess the impact of dust exposure on pulmonary function.