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PubMed1992

[Surgical stress stimulates release of polymorphonuclear leukocyte elastase from a segmented neutrophil].

The studies were performed to find out whether increased serum levels of polymorphonuclear leukocyte elastase (PMNE) depend on increase of segmented neutrophils or increase of PMNE release from a segmented neutrophil on 17 patients for various elective surgeries. Serum levels of PMNE, leukocyte count and leukogram were determined before incision (preoperation), as well as on the 1st, 3rd and 5th day after operation. Serum levels of PMNE, segmented cell count, stab cell count, stab cell-segmented cell ratio increased most on the 1st postoperative day and decreased thereafter. Leukocyte count showed no significant changes. Serum levels of PMNE correlated well with PMNE released from a segmented neutrophil, but not with leukocyte count or segmented cell count. It was concluded that increased serum levels of PMNE by surgical stress depend on the increased PMNE release from a segmented neutrophil but not on the increased segmented cell count.

Adult↗
PubMed1994

A central role for epidermal segment border cells in the induction of muscle patterning in the Drosophila embryo.

The correct patterning of muscles in the Drosophila embryo depends on the migration of developing muscles over the ectoderm and on the attachment of these muscles to specific attachment sites. We investigate the mechanisms that are involved in this process and describe experiments that allow a genetic dissection of the role of the ectoderm in muscle migration and attachment. We show that cells along the segmental border in the ectoderm are used by the developing muscles to reach their attachment sites. These segment border cells are recognized by dissociated myotubes in single suspensions in culture. Thus, developing muscles have properties that allow the specific recognition of the segment border cells and migrate to attach to these cells. The segment border cells are absent in the mutant wingless and naked. In these mutants, the muscles are severely disorganized. We show that this is not a mere consequence of disruption of the epidermis, since, in the mutant patched, where segmental patterning is affected, the segment border cells are present near their normal position; the muscles in this mutant are relatively organized. Similarly, in the mutant lines where ectopic segment border cells are present, the observed muscle derangement correlates well with the ectopic attachment sites that are present. Finally, we have analyzed mutants at the stripe locus and have shown that lethal alleles disrupt muscle organization during embryogenesis. Enhancer-trap alleles of stripe that we have analyzed show reporter gene expression in the segment border cells. Our results indicate a role for the segment border cells in guidance of migrating muscle fibers to their attachment sites.

Animals↗
PubMed1990

Intrinsic segmental identity of segmental founder cells of the leech embryo.

Segmentation occurs in several animal phyla, and the cellular mechanisms generating this structural periodicity vary considerably. In the leech, an annelid worm, segmental founder cells arise through a fixed cell lineage (Fig. 1), and come together in a longitudinally repeating array through a stereotyped pattern of morphogenesis. In this paper we demonstrate that founder cells forced to differentiate in a foreign segmental environment give rise to their normal, segment-specific clones of neuronal descendants, even in segments in which those neuronal phenotypes would not normally be observed. These findings indicate that the individual founder cells possess segmental identity at or shortly after the time of their birth, and further suggest that such identities are established by a mechanism in which the parent stem cell 'counts' mitotic cycles.

Animals↗
PubMed1983

[Spontaneous radial segmentation of cell nuclei: morphologic marker of T-cell neoplasms?].

Radial segmentation (RS) of leukocyte nuclei has been observed, for example, in leukemias (Rieder cells). In 6 of 8 patients with T-ALL, RS of neoplastic cells was found in the peripheral blood, whereas in 14 patients with non-T-ALL no RS cells were present. RS may be a morphologic marker for certain T-cell neoplasms, and with regard to ultrastructure it seems to be identical to heat-induced RS of non-neoplastic cells.

Cell Nucleus↗
PubMed1995

Live cell image segmentation.

A major requirement of an automated, real-time, computer vision-based cell tracking system is an efficient method for segmenting cell images. The usual segmentation algorithms proposed in the literature exhibit weak performance on live unstained cell images, which can be characterized as being of low contrast, intensity-variant, and unevenly illuminated. We propose a two-stage segmentation strategy which involves: 1) extracting an approximate region containing the cell and part of the background near the cell, and 2) segmenting the cell from the background within this region. The approach effectively reduces the influence of peripheral background intensities and texture on the extraction of a cell region. The experimental results show that this approach for segmenting cell images is both fast and robust.

Algorithms↗
PubMed1995

Expression of the cell cycle control gene, cdc25, is constitutive in the segmental founder cells but is cell-cycle-regulated in the micromeres of leech embryos.

The identifiable cells of leech embryos exhibit characteristic differences in the timing of cell division. To elucidate the mechanisms underlying these cell-specific differences in cell cycle timing, the leech cdc25 gene was isolated because Cdc25 phosphatase regulates the asynchronous cell divisions of postblastoderm Drosophila embryos. Examination of the distribution of cdc25 RNA and the zygotic expression of cdc25 in identified cells of leech embryos revealed lineage-dependent mechanisms of regulation. The early blastomeres, macromeres and teloblasts have steady levels of maternal cdc25 RNA throughout their cell cycles. The levels of cdc25 RNA remain constant throughout the cell cycles of the segmental founder cells, but the majority of these transcripts are zygotically produced. Cdc25 RNA levels fluctuate during the cell cycles of the micromeres. The levels peak during early G2, due to a burst of zygotic transcription, and then decline as the cell cycles progress. These data suggest that cells of different lineages employ different strategies of cell cycle control.

Amino Acid Sequence↗
PubMed1985

Variability in the terminations of GABAergic chandelier cell axons on initial segments of pyramidal cell axons in the monkey sensory-motor cortex.

Chandelier cell axons were studied in the sensory-motor cortex of adult monkeys. The axonal fields of Golgi-impregnated chandelier cells in layer II in motor cortex are flattened sagittally. The vertical terminal portions of the axons varied both in length and in the numbers converging to form terminations of greater or lesser complexity. Golgi-impregnated plexuses were embedded in plastic and resectioned serially at 2.5-3.0 micrograms. A single axonal field could have as many as 400 terminal rows. All lie 3-13 micrograms beneath pyramidal cell somata. These terminations are not randomly distributed but instead, form clusters. Further resectioning the plastic sections for electron microscopy revealed that all the terminations are on the initial axon segments of pyramidal cells and all form symmetric synaptic contacts. In immunocytochemical material stained for glutamic acid decarboxylase (GAD), the enzyme involved in the synthesis of GABA, GAD-positive boutons were found to form symmetric synaptic contacts with a variety of postsynaptic elements including the axon hillocks and axon initial segments of pyramidal cells. Serial reconstructions from electron micrographs revealed GAD-positive terminals synapsing with the axon initial segment of pyramidal cells joined by cytoplasmic bridges and forming vertically oriented rows identical to those of chandelier cell terminals identified positively in the resectioned Golgi material. The GAD-positive terminals forming initial segment synapses were never continuous with GAD-positive terminals forming axo hillock synapses. The latter probably arise from basket cell axons. Initial segments of pyramidal cell axons in layers II and III were contacted by more GAD-positive terminals than the initial segments of pyramidal cell axons in layer V. The largest pyramidal cells in layer III received the most synapses. Many larger pyramidal cells, identified as callosally projecting cells by the retrograde transport of horseradish peroxidase (HRP), were shown in serial electron micrographs to possess large numbers of initial segment synapses, comparable to those seen in the immunocytochemical material. Serial reconstructions of pyramidal cell axons from axon hillock to the first myelin internode in resectioned Golgi, immunocytochemical and HRP material showed that the number of synapses varied from 2 to 52 for layers II and III and from 2 to 26 for layer V. The number of synapses on the axon hillocks varied from zero to 12. The variability in these terminations may be an important factor in the shaping of the functional properties of the pyramidal cells.

Animals↗
PubMed1983

Segmentation of cell nuclei in tissue section analysis.

Image segmentation is a critical step in digital picture analysis, especially for that of tissue sections. As the morphology of the cell nuclei provides important biological information, their segmentation is of particular interest. The known segmentation methods are not adequate for segmenting cell nuclei of tissue sections; the reason for this lies in the optical properties of their images. We have developed new gradient methods of segmentation of previously presegmented images by taking these properties into account and by using the approximately circular shape of the cell nuclei as a priori information. In our first technique, the segment method, the images of the nuclei are divided into eight segments, special gradient filters being defined for each segment. This has enabled us to improve the gradient image. After searching for local maxima, the contours of nuclei can be found. In the second method, the method of transformation into the polar coordinate system (PCS), the a priori information serves to define a circular direction field for gradient computation and contour finding. In contrast with the first method, which offers a rapid, general idea about the nuclear shape, the PCS method permits precise segmentation and morphological analysis of the cell nuclei.

Animals↗
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↗
PubMed1974

Renewal of fatty acids in the membranes of visual cell outer segments.

The renewal of fatty acids in the visual cells and pigment epithelium of the frog retina was studied by autoradiographic analysis of animals injected with tritiated palmitic, stearic, or arachidonic acids. Most of the radioactive material could be extracted from the retina with chloroform-methanol, indicating that the fatty acids had been esterified in lipids. Analysis of the extracts, after injection of [(3)H]palmitic acid, revealed that the radioactivity was predominantly in phospholipid. Palmitic acid was initially concentrated in the pigment epithelium, particularly in oil droplets which are storage sites for vitamin A esterified with fatty acid. The cytoplasm, but not the nucleus of these cells, was also heavily labeled. Radioactive fatty acid was bound immediately to the visual cell outer segment membranes, including detached rod membranes which had been phagocytized by the pigment epithelium. This is believed to be due to fatty acid exchange in phospholipid molecules already situated in the membranes. Gradually, the concentration of radioactive material in the visual cell outer segment membranes increased, apparently as a result of the addition of new phospholipid molecules, possibly augmented by the transfer from the pigment epithelium of esterified vitamin A. Injected fatty acid became particularly concentrated in new membranes which are continually assembled at the base of rod outer segments. This localized concentration was short-lived, apparently due to the rapid renewal of fatty acid. The results support the conclusion that rods renew the lipids of their outer segments by membrane replacement, whereas both rods and cones renew the membrane lipids by molecular replacement, including fatty acid exchange and replacement of phospholipid molecules in existing membranes.

Animals↗
PubMed1996

The effect of ulinastatin, a human protease inhibitor, on the transfusion-induced increase of plasma polymorphonuclear granulocyte elastase.

Ulinastatin (UTI), a human protease inhibitor, inhibits polymorphonuclear granulocyte elastase (PMNE) release from granulocytes stimulated by several pathologic inflammatory processes. Blood transfusions increase plasma PMNE concentrations. We evaluated the effects of UTI on the transfusion-induced increase in PMNE. Thirty-nine patients undergoing gastrectomy were divided into four groups: Group A (n = 8), blood transfusion (-), UTI (-); Group B (n = 9), blood transfusion (+), UTI(-); Group C (n = 12), blood transfusion (-), UTI(+); and Group D (n = 10), blood transfusion (+), UTI(+). UTI of 300,000 U was infused in Groups C and D. White blood cell count (WBC), segmented cell count, plasma PMNE concentration, and PMNE release (PMNE concentration/segmented cell) were measured before, at the end of, and at 1 and 3 days after the operation. Although no significant differences were seen in WBC and segmented cell count among the groups, plasma PMNE concentration and PMNE release in Group B (transfusion without UTI) were significantly more than in Group A (no treatment) and Group D (transfusion with UTI) at the end of the operation, but the concentrations of the variables were not significantly different between Groups A and C (only UTI treatment). These results indicate that a single injection of 300,000 U of UTI inhibited transfusion-induced PMNE increase at the end of the operation. Thus, the present results may facilitate future studies testing the effects of UTI given at larger doses, or by a continuous administration, on the prevention of organ derangement after blood transfusion.

Adult↗
PubMed1992

Acetazolamide inhibition of basolateral Cl-/HCO3- exchange in rabbit renal proximal tubule S3 segment.

Cell pH (pH(i)) and cell membrane potential (Vb) were measured in isolated S3 segments of rabbit renal proximal tubule with double-barrelled microelectrodes to search for a possible effect of the carbonic anhydrase inhibitor, acetazolamide (ACZ), on Cl-/HCO3- exchange in the basolateral cell membrane. ACZ was found to retard and reduce the pH(i) response to bath Cl- removal reversibly with half-maximal inhibition at 0.42 mmol/l and a rather flat concentration dependence (Hill coefficient approximately 0.36). To determine whether the retardation resulted from inhibition of cytoplasmic carbonic anhydrase, which might have delayed the attainment of HCO3-/CO2 equilibrium, we have measured the response of pH(i) to step changes in PCO2 in the presence and absence of ACZ. ACZ greatly retarded the pH(i) response to CO2 steps; however, the concentration dependence differed (half-maximal inhibition at 18 mumol/l) and even at maximal ACZ concentrations the response to CO2 steps was more than twice as fast as the response to Cl- replacement. Since, in addition, the ACZ inhibition of Cl-/HCO3- exchange could not be overcome by increasing PCO2 we conclude that the ACZ effect on Cl-/HCO3- exchange in rabbit proximal tubule S3 segments does not result from inhibition of cytosolic or membrane-bound carbonic anhydrase, but from a direct interaction with the exchanger molecule.

Acetazolamide↗
PubMed1967

The renewal of photoreceptor cell outer segments.

The utilization of methionine-(3)H by retinal photoreceptor cells has been studied by radioautographic technique in the rat, mouse, and frog. In all three species, the labeled amino acid is concentrated initially in the inner segment of the cell. Within 24 hr, the radioactive material is displaced to the base of the outer segment, where it accumulates as a distinct reaction band. The reaction band then gradually moves along the outer segment and ultimately disappears at the apex of the cell, which is in contact with the retinal pigment epithelium. These findings are interpreted to indicate that the photoreceptor cell outer segment is continually renewed, by the repeated lamellar apposition of material (membranous discs) at the base of the outer segment, in conjunction with a balanced removal of material at its apex. The outer segment renewal rate is accelerated in frogs when ambient temperature is raised, and is elevated in both frogs and rats when the intensity of retinal illumination is increased.

Animals↗
PubMed1993

Human neutrophil granules and secretory vesicles.

The traditional classification of neutrophil granules as peroxidase-positive (azurophil, or primary) and peroxidase-negative (specific or secondary) has proven to be too simple to explain the differential exocytosis of granule proteins and incorporation of granule membrane into the plasma membrane which is an important aspect of neutrophil activation. Combined subcellular fractionation and immunoelectron microscopy has revealed heterogeneity among both peroxidase-positive and peroxidase-negative granules with regard to their content, mobilization and time of formation. Peroxidase-negative granules may be classified according to their content of lactoferrin and gelatinase: 15% of peroxidase-negative granules contain lactoferrin, but no gelatinase. 60% contain both lactoferrin and gelatinase. The term specific or secondary granule should be reserved for these two subsets. In addition, 25% of peroxidase-negative granules contain gelatinase but no lactoferrin. These should be termed gelatinase granules or tertiary granules. Gelatinase granules are formed later than specific granules and mobilized more readily. In addition, a distinct, highly mobilizable intracellular compartment, the secretory vesicle, has now been recognized as an important store of surface membrane-bound receptors. This compartment is formed in band cells and segmented cells by endocytosis. This heterogeneity among the neutrophil granules is of functional significance, and may also be reflected in the dysmaturation which is an important feature of myeloproliferative and myelodysplastic disorders.

Calcium↗
PubMed1993

Identification of tubular cell nephron segment origin in renal fine-needle aspirates.

Currently there are no definitive criteria for identification of the nephron segment origin of tubular cells in renal fine-needle aspirates. This information would be useful for determining the cortical or medullary location of aspirate specimens. To establish morphologic criteria for identifying tubular cell origin, we evaluated 60 allograft and four native kidney aspirates with immunocytochemistry (IC) and May-Grünwald-Giemsa (MGG) stains. IC markers included URO-3 and Tetragonolobus purpuras for proximal cells, URO-5 and Arachis hypogaea for distal cells, and URO-5, Arachis hypogaea, and anti-cytokeratin antibody for collecting duct cells. Cell and nuclear areas were measured morphometrically, and cell grouping and MGG staining characteristics were assessed. Proximal tubular cells have an area of 335 +/- 112 microns2 (IC strains) and 350 +/- 107 microns2 (MGG stain) with a nuclear:cytoplasm (N:C) ratio of 1:4. The cells occur singly or in small clusters of four to seven cells with abundant pale cytoplasm. Distal tubular cells measure 224 +/- 66 microns2 (IC stains) and 171 +/- 38 microns2 (MGG stain) with an N:C ratio of 1:2. They often form honeycomb aggregates of 10 to 20 cells with moderately dense cytoplasm. Cells of collecting ducts have areas of 96 +/- 32 microns2 (IC stains) and 99 +/- 35 microns2 (MGG stain) with an N:C ratio of 2:3. These cells are found in glandular clusters of two to seven cells with dense cytoplasm. All tubular cell size and staining characteristics were the same in allograft and native kidney samples.(ABSTRACT TRUNCATED AT 250 WORDS)

Biopsy, Needle↗
PubMed1995

Biosynthesis of granule proteins in normal human bone marrow cells. Gelatinase is a marker of terminal neutrophil differentiation.

Differentiation and maturation of myeloid cells is characterized by the sequential acquisition of two distinct cytoplasmic granule subsets, azurophil granules and specific granules. We recently showed the existence of a third granule subset, gelatinase granules. To investigate whether appearance of gelatinase granules marks a further step in maturation of myeloid cells beyond the appearance of specific granules, we sorted normal human bone marrow cells into one of three groups according to maturity by centrifugation on Percoll density gradients. The biosynthesis of myeloperoxidase (MPO) (an azurophil granule marker), lactoferrin and neutrophil gelatinase-associated lipocalin NGAL (specific granules markers) and gelatinase was then studied in each of these groups. We found that gelatinase was synthesized mainly in the group containing band cells and segmented cells. This contrasted with lactoferrin and NGAL, which were synthesized almost exclusively in the group containing myelocytes and metamyelocytes, and with MPO, which was mainly synthesized in the group containing myeloblasts and promyelocytes. Immunocytochemistry was in full agreement with the biosynthesis data, and showed that gelatinase appears in band cells, whereas NGAL and lactoferrin both appear in myelocytes. Thus, acquisition of gelatinase granules marks a step in neutrophil differentiation beyond the appearance of specific granules.

Animals↗
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↗