Pediatric cecal malfixation.
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Barium Sulfate↗
Biomedical subjects
H Coen
Publications and source records attributed to H Coen.
Factors influencing distant tele-evaluation in cytology, pathology, conventional radiology and mammography.
The present paper summarizes our 1 year's experience with the use of static high resolution videophones (9600 bauds transmission rate, lossless compression, 512 x 512 spatial resolution). The images (n = 610) belong to regular videoconsultation in cytology (160 images), (160 images), pathology (226 images), conventional radiology (50 images) and mammographies (174 images). The results showed an exponential relationship between agreement with 'gold standards' (true diagnosis of the case based on pathology, surgery and follow-up) and the time of training on screen diagnosis (r = 0.9726, P < 0.01) that increases (r = 0.983, P < 0.004) when the screen diagnosis training within the specific topic is examined. Conversely, no significant correlation is found when medical experience itself is considered (r = 0.31, P nonsignificant). Sufficient diagnostic response has been achieved after 1 year of training on screen diagnosis within a specific topic.
Cell Biology↗
Previous experience in teleradiology could serve as a first lesson to telepathologists.
The author draws the following conclusions from twenty years of experience with teleradiology and in telemedicine in general. 1) Standardise now. Use existing standards, keep protocols open for other partners. The use of "protected" or "slightly" modified standards will not open the market. On the contrary, it will slow down developments in telepathology. How many manufacturers are capable of exchanging images over normal communication lines (analog or ISDN) with others than themselves? 2) Develop adequate user-interfaces. Priority levels should be set. The display has to adapted to the user. For pathologists this means using a microscope to view the images that have been sent [11]. For radiologists this means a dynamic user-interface adapted to the radiologists needs and wishes and which provides the best possible working environment [5]. 3) Integration with the HIS. The purchase and installation of telemedicine equipment should be integrated in a whole informatisation strategy and not be considered as a standalone act.
Computer Communication Networks↗
Growth behavior of human pancreatic carcinoma xenograft correlates with nuclear features.
Two human pancreatic ductal adenocarcinomas with different growth rates were serially transplanted into nude mice. Feulgen-stained 4 microns sections and imprints from the xenografts were studied with a VICOM automated image analysis system. After pooling the results from two passages, with three mice in each passage, it was shown that of 23 nuclear parameters measured the following were correlated with a fast tumor growth rate: in sections, a decrease in heterogeneity of the chromatin and an increase in perimeter and nuclear area; in imprints, an increase in lesser diameter, in mean grey level difference between second neighboring pixels, and in total integrated optical density (DNA content). Several parameters differed significantly between passages, and between animals in the same passage. These findings suggest that the growth speed of pancreatic tumors may be predicted by nuclear parameters.
Adenocarcinoma↗
The rat liver cell nuclear imprint as a standard for DNA measurements.
Standards are used in DNA cytophotometry to determine the diploid reference value. Fixation and staining protocols have to be standardized because numerous sources of variation influence staining intensity of DNA. When Feulgen stained imprints of rat liver cell nuclei are used as an external DNA standard a significant difference of reference value of up to 60% between imprints, from the same liver and with all sources of variation minimized, is demonstrated. Different possible sources of intra-imprint variation were examined but its exact nature remains unknown. Due to this inter-imprint variation, the DNA-reference value from a single liver imprint is only an approximation with unknown error of the true diploid reference value. By drawing an aselective random sample of N diploid cells in M imprints the sampling distribution of TIOD (mean Total Integrated Optical Density) will have its expectation identical to the diploid reference value and is approached by TIOD (mean TIOD) with the confidence interval defined by the number, M, of imprints measured. The use of TIOD as an estimate of diploid reference value with known precision is proposed as a first approach for the definition of a standard for DNA measurements.
Animals↗
Influence of optical density on the automated segmentation of rat kidney lysosomes.
After staining for acid phosphatase, video-images were acquired from 0.5-micron sections of rat kidney. Lysosomes in proximal tubules were automatically segmented, using a VICOM digital image processor and measured for area, number and optical density (OD). The purpose of this study is to objectively evaluate the performance of the automated segmentation algorithm at different staining intensities (a) by measuring area after staining with different incubation times, reduced substrate concentration or by adding an inhibitor and (b) by 'simulating' a decrease in OD (reducing grey-values at each point of a digitized image). The results of the experiments showed that: (1) the algorithm will underestimate the size of lysosomes (a) when the OD in close to the local background and (b) when an area is larger than or close to the area of the lowpass square filter; (2) accuracy of the segmentation can be improved by comparing the results of feature extraction after segmentation of the same image at different relative OD levels; (3) lysosomes with very low OD, compared to background are delineated with a large error or not delineated at all and this cannot be corrected. Incorrectly delineated lysosomes can be identified and excluded from further calculations, or their measured area replaced by an estimate of the true area.
Acid Phosphatase↗
Automated cytometry of muscle fibre sections: size and spatial distribution of the four fibre types in young and adult rats.
An automated cytometry program was applied to the extensor digitorum longus muscle of young and adult rats. Lesser diameter and spatial distribution of about 4000 fibres were measured in digital images from ATPase-stained muscle sections. All fibre types grow thicker with age, but the coefficient of variation of the diameter is age-independent. At both ages, 2B fibres have the largest mean diameter and are most frequent. 2A fibres in young rats present a diameter smaller or equal to type 1 but then show a faster increase in size; their relative number increases from 20 to 28%. Consequently type 2A displays the most important change with age. The spatial distribution of fibres is mathematically expressed; most images show a random distribution of type 1 and type 2 fibres. Taking into account the variation of fibre size of each type, the number of fibres which should be measured in order to reach a specified precision was calculated.
Analysis of Variance↗
Fully automated measurements by light microscopy of tissue sections using a cellular array computer.
Software was developed for the acquisition, segmentation and analysis of microscopic OD-images on a VICOM digital image processor, extended with a VISIOMORPH morphoprocessor board. The delineation algorithms for peroxisomes, lysosomes, and nuclei in liver, kidney, and adrenal gland sections start by thresholding the difference between the original image and a low pass filtered version. The resulting binary mask is then processed by morphological operations in order to produce an object overlay. The efficiency of the programs is evaluated by comparing delineated objects at different OD-levels, created by varying the stain or by multiplying the original pixel values with constant factors. Manual delineation on some images is also used as a reference. More complex algorithms are used for the delineation of muscle fibres in ATP-ase-stained sections and immunocytochemically labelled cells in monolayer preparations. Muscle images from parallel sections with different stainings are matched with a coordinate transform, enabling the transfer of the object mask from a single delineated image to the unprocessed images and thus obtain all necessary information for fibre classification. After segmentation, the OD-images and their object overlays are fed into a data extraction program, measuring for each delineated object user-selected features. Data are sent to a VAX for statistical interpretation.
Adrenal Cortex↗
Automated measurement of kidney lysosomes by light microscopy. Influence of cyclosporine treatment.
After staining for acid phosphatase, video images were acquired from 1-micron sections of the kidneys of rats treated with cyclosporine. Automated segmentation of the lysosomes was followed by measurements of their area, number and optical density; tubular area was delineated manually. In addition to small lysosomes, representing more than 80% of the total number, all kidneys contained a second population of larger organelles. Cyclosporine treatment with 50 mg/kg/day for one week and with 25 mg/kg/day for three weeks, but not with 25 mg/kg/day for one week, induced a significant increase of lysosomal area, especially in the larger organelles (+200%). In a few animals, this was accompanied by a reduction in the number of lysosomes, suggesting a fusion of the organelles. Other parameters were not consistently modified by treatment. Cyclosporine treatment also elicited the appearance of fat droplets; however, lysosomes were not enlarged in tubular cells containing fat droplets.
Animals↗