Search PubMed⌕ Search

Biomedical subjects

I T Young

Publications and source records attributed to I T Young.

At least 19 recordsLinked to original sources
PubMed1991

Towards a quantitative grading of bladder tumors.

The histological inspection of tumor tissue for the purpose of reporting a tumor grade is a problem of significant clinical importance. The grading by a pathologist is only partly reproducible due to vaguely defined, subjective criteria. In this article we describe and evaluate a set of measurable features that quantitate the differences in tumor tissue. Different aspects of the reproducibility of the measurements under varying conditions of image selection, focus, and noise have been investigated. Three hundred thirty-three images were digitized from 111 bladder tissue sections (4 microns thick, Feulgen stained), using the ICAS microscope-camera platform. A segmentation routine was developed to segment the images into nuclei and background without any user interaction. Size, shape, optical density, and texture features were measured on and among the objects found by this segmentation routine using the image analysis package Acuity. The results of the measurements showed that there is a significant quantitative difference between grade 1 and grade 3 tumors. Grade 2 tumors can be described as "in between grade 1 and grade 3" and falling somewhere on an increasing scale between grades 1 and 3. Grade 2 tumors do not seem to represent a statistically distinct population. The procedure described here is shown to be quite reproducible in the presence of noise, reasonably reproducible in the event of a modest amount of defocusing (with grade 3 tumors exhibiting the most sensitivity), and less reproducible in the context of which fields-of-view are chosen for analysis.

Epithelium↗
PubMed1990

The Athena semi-automated karyotyping system.

In this article we describe Athena, a system that provides for semi-automated karyotyping of metaphase spreads. The system is based upon the Macintosh II computer. It uses software that is written entirely in C and consists of approximately 200 Kbytes of executable code. Athena provides automated segmentation of metaphase images into individual chromosomes, automated measurements on each banded chromosome, and automated classification into the standard Paris-convention karyotype. Furthermore, the system provides the ability to construct one or more chromosome data bases to represent the types of metaphase spreads and staining techniques that may be used in a given laboratory. Because we believe that it is impossible to construct a system that can achieve perfect segmentation, perfect separation of touching and overlapping chromosomes, perfect localization of the centromeres, and perfect classification, the system offers the possibility for interaction at each of the above stages using the well-accepted Macintosh user interface.

Centromere↗
PubMed1990

Experience with the Athena semi-automated karyotyping system.

The traditional analysis and assembly of metaphase chromosomes into a karyogram is a slow and tedious process requiring intermediate photographic steps and manual manipulation of the chromosome images. Much of this task is highly repetitive and readily lends itself to partial automation. Semi-automated karyotyping systems now are being used increasingly in both clinical and research cytogenetic laboratories. Digital image processing techniques are used to capture, manipulate, and make an initial classification of chromosome images. The Athena system uses commercially available components based on a Macintosh II personal computer. Digital image processing procedures automatically isolate chromosome images from the metaphase and arrange them into a karyogram, using information about relative chromosome length, centromeric index, and banding pattern. The operator uses the intuitive graphics interface of the Macintosh computer to monitor each phase of the analysis, to resolve any problems in isolating chromosome images, and to rearrange the individual chromosome images while assembling the final karyogram. Athena is designed as a semi-automated karyotyping system that is easy to learn and has sufficient power and versatility for routine use in the analysis of human metaphase chromosomes.

Humans↗
PubMed1988

Sampling density and quantitative microscopy.

The sampling densities required for the quantitative analysis of digitized microscope images is discussed. It is shown that the Nyquist sampling theorem is not the proper reference point for determining the sampling density when the goal is measurement, although it may be a proper reference point when the goal is image filtering and reconstruction. The problems associated with signal truncation--the use of a finite amount of data--and the finite amount of time available for computation make it impossible to reconstruct an arbitrary image, even if it is bandlimited. Two examples taken from straightforward measurement problems exhibit the fundamental problems associated with the measurement of analog quantities from digital data and the role played by the sampling density.

Image Processing, Computer-Assisted↗
PubMed1986

Characterization of chromatin distribution in cell nuclei.

In this paper we develop four measures to describe the distribution of nuclear chromatin. These measures attempt to describe in an objective and meaningful way the heterogeneity, granularity, condensation, and margination of chromatin in cell nuclei. Starting with a high-resolution digitized image of a cell where the nuclear pixels have been identified, the four measures may be rapidly estimated. The range of each is derived and the interpretation of the measures in the context of chromatin compaction and distribution is developed. Implementation issues such as sampling density, thresholding and subsequent pre-processing, and algorithmic complexity are discussed.

Animals↗
PubMed1985

A comparison of different focus functions for use in autofocus algorithms.

A number of functions for the autofocusing of microscopes and other optical instruments are to be found in the literature. In this article we compare 11 of them to determine, in an objective manner, which functions are most suitable for implementation with real-time video acquisition systems. Three different images, each representing a typical class of image, are used in the comparison. Among the best focus functions found in our study are the squared magnitude gradient, the squared Laplacian, and the normalized image standard deviation.

Microscopy↗
PubMed1979

An immunocytochemical approach to cell kinetics automation.

Antibodies specific for 5-bromodeoxyuridine (BrdUrd) can be used to measure labeling indices in an automated system by image analysis. The antibody, used with an indirect immunoperoxidase technique, will detect de novo DNA synthesis subsequent to growing the cells for various time intervals in 5-bromodeoxyuridine-containing medium. Asynchronously growing CHO cells were pulsed with 3H-5-bromodeoxyuridine, fixed, denatured and then stained with anti-bromouridine antiserum. Peroxidase-coupled goat anti-rabbit IgG was used as the secondary antibody, and slides were stained with diaminobenzidine. Cells which are positive display a reticular pattern indicative of replicating chromatin. "Labeling indices" were generated by scanning the nuclei by TV image analysis. The percentage of labeled cells by the immunocytochemical technique correlates well with that found by autoradiography. Some of the applications of this automated method include cell kinetics and analysis of S-phase by pattern recognition technique.

Animals↗
PubMed1979

Transformation of nuclear morphology during cellular maturation.

Using in vivo labeling of mouse leukocytes with tritiated thymidine, cells in the neutrophilic series were studied to determine the change in their nuclear shape as a function of maturation level. Several morphologic shape parameters including perimeter and bending energy were used to quantify the distribution of the nuclear morphology in a given age cohort. The change in these distributions as a function of calender age level was determined. The two parameters named above were used to test the possibility of inferring the age from the quantitative morphology.

Animals↗
PubMed1978

Loss of division potential in vitro: aging or differentiation?

We have examined the hypothesis that diploid cells grown in vitro age, and propose that only proliferative potential and not life-span is telescoped. We suggest that explanted or transplanted diploid cells are driven to divide by the process of subculturing in vitro or in vivo and, in response to this pressure, also complete their differentiation and become refractory to further mitotic stimulation. We conclude that differentiation rather than "mortality" distinguishes diploid from transformed cells and that the former may not age in vitro, but are lost because culture methods are selective for cycling cells.

Cell Cycle↗
PubMed1977

The automated classification of mitotic phase for human chromosome spreads.

A system has been developed that automatically recognizes the mitotic phase of human chromosome spreads for karyotyping. Suitable spreads are classified into one of five subphases of mitosis. Classification is performed on the basis of summed chromosome length and most probable chromosome width. Classification requires 100-500 msec. A television camera scans the spread through microscope optics; computer and special purpose electronics process the video signals to generate run length histograms. The histograms are used to determine mitotic phase. Unbanded spreads, 133, were classified with a 4.5% error rate. One hundred banded spreads were classified with a 15% error rate.

Autoanalysis↗
PubMed1977

Proof without prejudice: use of the Kolmogorov-Smirnov test for the analysis of histograms from flow systems and other sources.

In this paper the Kolmogorov-Smirnov statistical test for the analysis of histograms is presented. The test is discussed for both the two-sample case (comparing fn1(X) to fn2 (X)) and the one-sample case (comparing fn1 (X) to f(X)). Presentation of the specific algorithmic steps involved is done through development of an example where the data are from an experiment discussed elsewhere in this issue. It is shown that the two histograms examined come from two different parent populations at the 99.9% confidence level.

Immunoglobulin D↗
PubMed1976

A technique for multiple-cell chromosome karyotyping.

A new approach to a system for chromosome karyotyping is presented. The system assembles the information about chromosomes from several cells at a time, thereby filtering out noise due to variations in the slide preparations. The system makes i possible to use metaphase spreads which are incomplete due to missing chromosomes, touching and overlapping chromosomes and stain particles. The system gives a precise description of the chromosome complement in terms of distribution function parameters, with the uncertainty of the parameters specificed. The system is adaptive with respect to the initial reference parameter set so that both recognition of normal chromosomes, in spite of the variation displayed among individuals, and identification of aberrant chromosomes are possible. The precise chromosome descriptors can be used to detect differences between the tested individual and various references, in order to find chromosomal abnormalities.

Autoanalysis↗
PubMed1976

Automatic detection and localization of sister chromatid exchanges.

Sister chromatids of human metaphase chromsomes from cells which have replicated twice in medium containing 5-bromodeoxyuridine exhibit unequal fluorescence when stained with the dye 33258 Hoechst. Sister chromatid exchanges occurring in these chromosomes are apparent as interchanges of brightly and dully fluorescing chromatids. A technique for detecting such exchanges by computer analysis of chromsome images has been developed and found to campare favorably with manual methods. The exchanges have been localized in the context of quinacrine banding patterns.

Autoanalysis↗
PubMed1975

A measurement technique for cell adhesiveness.

Determination of the percentage of cells in clumps on a stained smear of human peripheral blood porvided a useful, accurate technique for measuring cell adhesiveness. Smears of human peripheral blood drawn with EDTA were prepared on a blood slide centrifuge, stained, and examined under a light microscope. Statistical analysis showed that the method resulted in a Poisson distribution of particles on the slide, where a particle was considered to be a simple cell, or two or more cells which appeared to be touching, Analysis of the distributions of erythrocytes and leukocytes showed that clumps were formed before the cells were deposited on the slide. When adhesiveness of erythrocytes or leukocytes was increased by incubation with antiserum to the corresponding cell type, the percentage of that cell type in clumps increased proportionately, Preliminary results using the method showed that normal human donors had similar to 1% of their erythrocytes and 1-5% of their leukocytes in clumps. In chronic myelocytic leukemia, as many as 60% of the leukocytes were in clumps.

Animals↗
PubMedDate not supplied

An analysis technique for biological shape-II.

A discrete function representing the curvature of closed contours has been derived. The function is easily computable and has properties desirable for use in shape analysis. Two curvature measures (as well as the traditional P2A) have then been applied to a set of shapes extracted from leukocyte nuclei in order to evaluate their effectiveness as numeric descriptors of shape complexity. Bending energy, (BEN), was shown to be, on the average, the most sensitive indicator of complex shape, normalized mean absolute curvature (NMAC) was next, and P2A was last. Bending energy could also have important biolgical significance due to its possible relation to developmental processes. Further studies on bending energy will be necessary in order to substantiate this possibility. Many of the discrepancies between P2A, NMAC, BEN, and the study subjects are explainable by the lack of "syntactic", or form, information used by the computer features. If an observer really classifies an object by decomposing it into simpler pieces, then a more sophisticated shape analysis procedure must be used. Such a procedure will be described in a sequel to this paper.

Cell Nucleus↗