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Results for “Cell segmentation”

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At least 19 recordsLinked to original sources
PubMed1977

Bone marrow cell scene segmentation by computer-aided color cytophotometry.

Computer scene segmentation of touching cell images in bone marrow, on the basis of color information, is achieved using digitized scans at three different wavelengths of light. With trivariate histograms and Euler's coordinate transformation, it is possible cytophotometrically to isolate, on the basis of chromatic differences, individual heterogeneous cells located in cell groups. The ability of the described computer methods to isolate correctly the touching cell images is determined by visual comparison of the cells as seen in the microscope and the computer-generated displays of the scanned and segmented scenes.

Bone Marrow Cells↗
PubMed1979

Membrane-dependent guanine nucleotide binding and GTPase activities of soluble protein from bovine rod cell outer segments.

Soluble proteins can be extracted by osmotic shock of purified rod (photoreceptor cell) outer segments that have intact plasma membranes. The soluble proteins include a component that contains tightly bound GDP-Exchange of this GDP with exogenous nucleotide is catalyzed by (and requires) the membranes from the outer segments. ATP does not participate in these reactions. Approximately one-half of the binding sites in the soluble component require GTP as the source of exogenous nucleotide; the remainder accept GTP or GDP with equal facility. When exogenous GTP is the source of bound nucleotide, it is found in the complex in the form of GDP. Exchange of bound nucleotide with GTP is stoichiometrically related to GTPase activity; this activity is highly dependent upon the presence of both membranes and soluble protein. The soluble nucleotide binding protein was purified by making use of the fact that it binds tightly to the membranes (under conditions of moderate ionic strength) in the absence of GTP and can be eluted by solutions containing low concentrations of GTP (but not GDP or ATP, nor can it be eluted by GTP-free solutions of low ionic strength). The purified protein contains two polypeptide chains of molecular weights 41,000 and 37,000; these are the major species that can be extracted from the outer segments by osmotic shock, and they constitute approximately 7% of the total protein of the isolated organelle.

Animals↗
PubMed1979

A thresholding method for automatic cell image segmentation.

An algorithm for automatic segmentation of PAP-stained cell images and its digital implementation is described. First, the image is filtered in order to eliminate the granularily and small objects in the image which may upset the segmentation procedure. In a second step, information on gradient and compactness is extracted from the filtered image and stored in three histograms as functions of the extinction. From these histograms, two extinction thresholds are computed. These thresholds are suitable to separate the nucleus from the cytoplasm, and the cytoplasm from the background in the filtered image. Masks are determined in this way, and finally used to analyse the nucleus and the cytoplasm in the original image.

Cell Compartmentation↗
PubMed1978

Further scanning electron microscope studies of lizard auditory papillae.

The papillae basilares of 12 species of lizards from seven different families were studied by SEM. The iguanids, Sceloporus magister and S. occidentalis, have typical "iguanid type" papillae with central short-ciliated unidirectional hair cell segments and apical and basal long-ciliated bidirectional hair cell segments. These species of Sceloporus are unique among iquanids in that the bidirectional segments consist of but two rows of hair cells. The agamids, Agama agama and Calotes nigrolabius, have an "agamid-anguid type" papilla consisting of an apical short-ciliated unidirectional segment. Agama agama is unusual in having a few long-ciliated hair cells at the apical end of the apical short-ciliated segment. The agamid, Uromastix sp., has an "iguanid type" papilla with a central short-ciliated unidirectional segment and apical and basal bidirectional segments. The anguid, Ophisaurus ventralis, has an "iguanid" papillar pattern with the short-ciliated segment centrally located. All the short-ciliated hair cells of the above species are covered by a limbus-attached tectorial network or cap and the long-ciliated hair cells, only by loose tectorial strands. The lacertids, Lacerta viridis and L. galloti, have papillae divided into two separate segments. The shorter apical segment consists of opposingly oriented, widely separated short-ciliated cells covered by a heavy tectorial membrane. The apical portion of the longer basal segment consists of unidirectionally oriented hair cells, while the greater part of the segment has opposingly oriented hair cells. The xantusiids, Xantusia vigilis and X. henshawi, have papillae made up of separate small apical segments and elongated basal segments. The apical hair cells are largely, but not exclusively, unidirectional and are covered by a heavy tectorial cap. The basal strip is bidirectional and the hair cells are covered by sallets. The kinocilial heads are arrowhead-shaped. The papilla of the cordylid, Cordylus jonesii, is very similar to that of Xantusia except that the apical segment is not completely separated from the basal strip. The papilla of the Varanus bengalensis is divided into a shorter apical and a longer basal segment. The hair cells of the entire apical and the basal three quarters of the basal segment are opposingly oriented, not with reference to the midpapillary axis but randomly to either the neural or abneural direction. The apical quarter of the basal segment contains unidirectional, abneurally oriented hair cells. The entire papilla is covered by a dense tectorial membrane. The functional correlations of the above structural variables are discussed.

Animals↗
PubMed1979

Neutrophil marrow profiles in patients with rheumatoid arthritis and neutropenia.

Neutrophil marrow cellularity was determined in 14 neutropenic patients with rheumatoid arthritis (RA) from measurements of neutrophil-normoblast ratios in marrow biopsies and ferrokinetic estimates of marrow normoblasts. A marrow profile was developed for each patient comprising the numbers of promyelocytes and myelocytes, of metamyelocytes and bands, and of segmented neutrophils in whole marrow. In each case a maturation ratio was calculated by dividing the number of metamyelocytes and bands by the number of promyelocytes and myelocytes. The physiologic marrow response to loss of neutrophils from circulation was assumed to be an increase in promyelocytes and myelocytes due to proliferation and influx, a reduction in segmented cells due to early release, and a normal maturation ratio. The results were interpreted in the light of the 95% confidence limits for data previously obtained from 13 normal subjects: in patients with neutropenia reduced or basal numbers of promyelocytes and myelocytes were interpreted as absence of the anticipated proliferative response; increased numbers of marrow segmented cells were attributed to failure of release; a low maturation ratio was assessed to reflect intramedullary cell loss. The pattern in two patients with Felty's syndrome was consistent with a physiological response to neutrophil destruction. The other 12 patients had neutrophil marrow abnormalities. Seven patients with Felty's syndrome and four patients without splenomegaly had absolute or relative hypoplasia of neutrophil marrow or low maturation ratios. One patient with a normal spleen size had an increased number of marrow segmented cells yet failed to mobilize cells normally in response to dialysis coil-activation of C3. Abnormalities of neutrophil marrow may contribute to neutropenia in RA irrespective of the presence of splenomegaly. Recognition of neutrophil marrow abnormalities in these patients may be of value in prognosis and management.

Adult↗
PubMedDate not supplied

Fundamental study of automatic cyto-screening for uterine cancer. II. Segmentation of cells and computer simulation.

In images of Papanicolaou stained cells 64 gray levels have been differentiated by scanning densitomery. One of the two peaks in a differential histogram indicates the threshold of the cytoplasm, the other that of the nucleus. The two modes indicate where in the digitized image of good segmentation of the cell from its background and the nucleus from the cytoplasm can be accomplished.

Cell Nucleus↗
PubMed1977

High resolution analysis of cervical cells--a progress report.

This paper presents preliminary results of research toward the development of a high resolution analysis stage for a dual resolution image processing-based prescreening device for cervical cytology. Experiments using both manual and automatic methods for cell segmentation are described. In both cases, 1500 cervical cells were analyzed and classified as normal or abnormal (dysplastic or malignant) using a minimum Mahalanobis distance classifier with eight subclasses of normal cells, and five subclasses of abnormal cells. With manual segmentation, false positive and false negative error rates of 2.98 and 7.73% were obtained. Similar experiments using automatic cell segmentation methods yielded false positive and false negative error rates of 3.90 and 11.56%, respectively. In both cases, independent training and testing data were used.

Autoanalysis↗
PubMed1976

Hybridization of mRNA from adenovirus-transformed cells to segments of the adenovirus genome.

Cytoplasmic viral-specific RNA from the 8617 line of adenovirus type 2 (Ad2) transformed rat cells was hybridized to DNA fragments derived either by Eco-RI or Sma-I restriction endonucleases. Three discrete classes of viral RNA (26S, 20S, and 15S) were detected by hybridization of total cytoplasmic RNA with the fragment, and all of these RNA molecules also hybridized to the much smaller Sma-E fragment of Ad2 DNA. Poly (A)-containing RNA (exposed to 90% formamide) contained only the 20S and 15S mRNA species, suggesting that the 26S RNA might be an aggregated species. Viral RNA of the same size derived from the same regions of the genome has not been detected in lytically infected cells, suggesting some change in the pattern of transcription or RNA processing of the Ad2 DNA in the integrated state.

Adenoviridae↗
PubMed2025

Measuring Cell Dimensions in Fission Yeast Using Machine Learning.

In fission yeast (Schizosaccharomyces pombe), cell length is a crucial indicator of cell cycle progression. Microscopy screens that examine the effect of agents or genotypes suspected of altering genomic or metabolic stability and thus cell size are crucial for studying disruptions to cell cycle dynamics. This method is based on using an automated cell segmentation algorithm to measure S. pombe cells imaged by brightfield (BF) microscopy methods. PhotoPhenosizer (PP) is a machine learning-based tool designed for automated cell measuring and dimensional analysis of morphology frequency distributions. Integration of this method into large-scale pipelines for tracking cell dimension change streamlines morphological measurements, which facilitates the examination of cellular responses to genomic and metabolic stresses. In this protocol, we use PP to observe the effect of genomic instability on cell size dynamics over a 12-day chronological lifespan assay. Our results show that relative to wild-type cells, a replication stress mutant shows larger cells during chronological aging in excess glucose media. Our results are consistent with activation of checkpoints that regulate cell morphology in response to DNA damage. This method's application highlights the relevance of its incorporation in experimental routines that require large-scale image processing and its adoption by users with routine needs in S. pombe molecular research projects.

Schizosaccharomyces↗
PubMed1977

The effect of transposition to jejunum on epithelial cell kinetics in an ileal segment.

Epithelial cell kinetics were studied in an ileal segment after transposition to proximal jejunum. The number of cells per villus column in the transposed ileum increased after 4--7 days to reach values normal for jejunum after 14--30 days. This increase was accompanied by a simultaneous increase in the number of cells per crypt column up to 130% of values in jejunum and ileum in situ. The percentage of labelled crypt cells, after labelling with 3H-thymidine, and the relative size of the proliferative cell compartment in the crypt in the transposed ileum did not differ from values in the ileum in situ at any time interval after surgery. The total proliferative activity per crypt, which was determined by scintillation counting of isolated crypts after 3H-thymidine labelling, increased two-fold from 7 days after surgery. Cell migration studies showed that the increase in the number of villus cells was probably not caused by a change in the life span of the epithelial cells. It seems that the increase in the number of villus cells in ileal epithelium after transposition to proximal jejunum is brought about by an enlargement of the crypt, while the relative size of the proliferative cell compartment in the crypt remains unchanged.

Animals↗
PubMed1976

Spontaneous and oxalate-induced radial segmentation of the nuclei of lymphocytes from peripheral blood from patients with chronic lymphocytic leukaemia.

Radial segmentation of nuclei of lymphocytes from peripheral blood from 18 patients with chronic lymphocytic leukaemia was studied in heparinized blood samples incubated with and without oxalate, for 6 h, at 20 degrees C, and 37 degrees C. The yield of radially segmented nuclei was the same after incubation at 20 degrees C as at 37 degrees C. Treatment with sodium oxalate resulted in an increased formation of radial segmentation to the same extent at 20 degrees C as at 37 degrees C. No correlation was found between the size of the lymphocytes and the frequency of radially segmented cells. The number of radially segmented nuclei did not vary with the WBC or Hb value. Cytostatic treatment with chlorambucil and cyclophosphamide did not inhibit the formation of radially segmented nuclei.

Cell Nucleus↗