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K Preston

Publications and source records attributed to K Preston.

At least 37 records · Page 2Linked to original sources
PubMed1987

Subclassification of follicular lymphomas by computerized microscopy.

The pilot feasibility study reported was carried out to determine whether computerized morphometry could be used to discriminate between different subtypes of follicular lymphomas. Thirteen cases of follicular lymphomas of the small cell and large cell types were examined by map-guided computerized microscopy. Initially, each specimen was digitized over a 5,120- X -5,120-microns area. Follicle maps depicting well-defined follicles were generated from these digitized images and used to guide a robot microscope to examine follicular center cells using from 20 to 100 fields, each 160 X 160 microns. Mathematical morphology was used to estimate the number of connected regions within each field examined. Based on the assumption that each connected region corresponded to a cell nucleus, it was expected that the number of connected regions found per unit area would correlate with the number of cells per unit area. Three prototypical small cell lymphomas and three prototypical large cell lymphomas were used as a training set to calibrate the methodology. Data obtained on these prototypical cases were used to establish statistical decision boundaries. Seven test cases, judged to be less typical but classifiable by experts, were then examined. Five of the seven were classified correctly, and the remaining two were identified as outliers. These results suggest that subclassification of follicular lymphomas may be aided by computerized microscopy. This pilot feasibility study is currently being expanded using a much larger sample of case material.

Diagnosis, Differential↗
PubMed1986

Monocular and binocular acuity estimation in 18- to 36-month-olds: acuity card results.

The acuity card procedure is a useful method for measuring visual acuity in infants 1 to 12 months of age. The results of the present study indicate that the procedure is also a viable method for estimating acuity in children 18 to 36 months of age. Monocular and binocular estimates of acuity were obtained with the acuity card procedure on 36 normal children, 9 each at ages 18, 24, 30, and 36 months. At each of the ages, means and SD's of acuity estimates agreed well with acuity norms from established operant procedures. Mean durations for monocular and binocular estimates averaged 2 to 4 min, and nearly 100% of children were tested successfully both monocularly and binocularly. The flexibility of the required response and the short test times make the acuity cards a promising test of visual acuity in this typically difficult-to-test age range.

Child Development↗
PubMed1986

Assessment of visual acuity in infants and children: the acuity card procedure.

The 'acuity card' procedure described here is a simplified method of testing visual acuity of infants and young children, and has been developed to allow preferential looking to be assessed in a laboratory or clinic. A higher proportion of children can be tested successfully than has been reported for more traditional procedures. Initial studies indicate that the acuity card procedure is a fast, accurate method for assessing the acuity of normal infants and children, and those with visual or neurological impairments, across a wide age-range and in both clinical and laboratory settings.

Child Development↗
PubMed1986

High-resolution image analysis.

In many departments of cytology, cytogenetics, hematology, and pathology, research projects using high-resolution computerized microscopy are now being mounted for computation of morphometric measurements on various structural components, as well as for determination of cellular DNA content. The majority of these measurements are made in a partially automated, computer-assisted mode, wherein there is strong interaction between the user and the computerized microscope. At the same time, full automation has been accomplished for both sample preparation and sample examination for clinical determination of the white blood cell differential count. At the time of writing, approximately 1,000 robot differential counting microscopes are in the field, analyzing images of human white blood cells, red blood cells, and platelets at the overall rate of about 100,000 slides per day. This mammoth through-put represents a major accomplishment in the application of machine vision to automated microscopy for hematology. In other areas of automated high-resolution microscopy, such as cytology and cytogenetics, no commercial instruments are available (although a few metaphase-finding machines are available and other new machines have been announced during the past year). This is a disappointing product, considering the nearly half century of research effort in these areas. This paper provides examples of the state of the art in automation of cell analysis for blood smears, cervical smears, and chromosome preparations. Also treated are new developments in multi-resolution automated microscopy, where images are now being generated and analyzed by a single machine over a range of 64:1 magnification and from 10,000 X 20,000 to 500 X 500 in total picture elements (pixels). Examples of images of human lymph node and liver tissue are presented. Semi-automated systems are not treated, although there is mention of recent research in the automation of tissue analysis.

Blood Cell Count↗
PubMed1986

Visual acuity screening of infants and young children with the acuity card procedure.

A new acuity test for infants and young children between 1 and 36 months of age is described. The test was used to evaluate the acuities of 66 infants and young children during a one-day vision screening. At least one estimate of visual acuity was obtained from 63 of the 66 children. Fifty-two of the children completed two monocular acuity tests (or two monocular tests plus a binocular test). The average total test time for these 52 children was less than 15 minutes. Results indicate that the acuity card procedure can be used as a complement to standard optometric tests for large-scale screening of infants and young children.

Child, Preschool↗
PubMed1983

Relationship between cell size and weight of the human liver. An automated morphometric study.

Using a machine-vision system for the analysis of multicolor multicellular images, an algorithm, consisting of cellular logic operators, was developed for estimating the average cross-sectional area of cells in the liver. A total of 28 three-color histologic images from 22 variable-weight autopsied livers were digitized and processed. The data collected showed a positive correlation, albeit weak, between the weight of the liver and the cell size. This correlation was not visually evident, which demonstrates the utility of machine vision in histopathology.

Adult↗
PubMed1982

Neurochemical similarities between d,l-cathinone and d-amphetamine.

Cathinone, the principal alkaloid of Khat, was compared to the psychomotor stimulant d-amphetamine on a number of neurochemical measures. Like d-amphetamine, d,l-cathinone released and blocked the uptake of tritiated dopamine (DA) in synaptosomal preparations. In addition, repeated high doses of d,l-cathinone produced long-lasting DA depletions in various rat brain regions and decreased the number of synaptosomal DA uptake sites in a manner similar to that seen after repeated d-amphetamine administration. Importantly, this DA neurotoxic effect of d,l-cathinone, like that of d-amphetamine, is selective since regional brain levels of norepinephrine (NE) or serotonin (5-HT) are not altered on a long-term basis by repeated administration of d,l-cathinone. These findings are discussed with reference to the current practice of Khat leaf chewing by people in north-eastern Africa.

Alkaloids↗
PubMed1980

Differentiation of cells in abnormal human liver tissue by computer image processing: a preliminary investigation to diagnostic microscopy.

The initial development of algorithms for the analysis of multicolor multicellular images of liver tissue sections is described. Using a three-color image recorded by an automated light microscope, a sequence of cellular logic operators was applied to the task of differentiating between hepatocyte and leukocyte nuclei in a section taking advantage of both spatial and chromatic features, namely, that hepatocyte nuclei usually appear larger than those of leukocytes and, in red illumination, are likely to be more transparent. Optimally, the developed algorithms properly differentiated 90% of the hepatocyte nuclie and 85% of the leukocyte nuclie; this performance level appears to equal that of a microscopist. The microscopist, however, rarely analyses all cells; thus, computer differentiation of cells eventually may provide an important new dimension to clinical histopathology.

Cell Nucleus↗
PubMed1973

Bloom's syndrome.

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Abnormalities, Multiple↗