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PubMed1981

Nomarski differential interference contrast studies of murine lymphocytes.

Nomarski differential interference contrast microscopy (DIC) of lymphocyte surface morphology was combined with immunofluorescence studies on T and B cell markers on the thymus, lymph nodes, spleen, peripheral blood lymphocytes and thoracic duct lymph of female CBA mice. DIC identified smooth cells and several categories of villous cells; more extreme forms were present in lymph. Most B cells seemed to belong to the smooth group and most peripheral T cells to the villous group. Thymus cells were almost entirely smooth, but treatment with cortisone increased the proportion of villous cells to 50%. The surface morphology of lymphocytes was highly labile preventing direct identification or separation of T and B cells. In vivo removal of T cells by adult thymectomy, lethal irradiation and bone marrow reconstitution caused the villous cells to decrease. During recovery from irradiation, T lymphocytes tended to parallel villous cells, B lymphocytes smooth cells, but were differences between the spleen and lymph nodes. Mice deprived of T1 cells by adult thymectomy showed a modest decrease of smooth cells in the spleen and blood; mice depleted of T2 cells by anti-lymphocyte serum, or which were naturally deficient in T2 cells, were markedly lacking in villous cells. Thoracic duct lymph, which is rich in T2 cells, had a high proportion of extremely villous lymphocytes. Exposure to lymph induced extreme villous features in lymph node cells, and it was found that the thoracic duct lymph was markedly hypertonic to serum, although varying in osmolarity throughout the day. It is suggested that the villous shape of T2 cells is a circulatory adaptation, necessitated by the peculiar character of the lymphatic system in mice.

Animals↗
PubMed1981

Nucleated thrombocytoid cells. II. Phase- and interference-contrast microscopic studies on blood cells of the domestic fowl.

The so-called nucleated thrombocytes of the domestic fowl (and mallard) were analyzed intravitally by use of phase- and interference-contrast microscopy with regard to their morphology and functional state, and in comparison to other avian blood cells and mammalian blood platelets. Since nucleated thrombocytoid cells of birds do not differ in size from white blood cells, they are automatically included in differential cell counts. They can easily be confused with other white blood cells and even with erythrocyte ghosts, which also appear to be hemostatically active elements. However, the nucleated thrombocytoid cells displayed a characteristic, definite morphology. The platelet-like spreading process and elongation of aging cells in vitro to spindle forms deserve special attention. A technique of counting live avian blood cells was used to determine their values in chickens of different sexes and ages.

Animals↗
PubMed2000

Characterization of an extremely motile cellular network in the rotifer Asplanchna spp. Structure, kinetics, and the cytoskeleton.

The pseudocoelomic body cavity of the rotifer Asplanchna spp. contains free cells that form a highly dynamic, three-dimensional polygonal network of filopodia. Using video-enhanced differential interference contrast microscopy, we have qualitatively and quantitatively characterized the motion types involved with network motility: (1) filopodial junctions are displaced laterally at 10.52 +/- 0.46 microns/s; (2) free-ending filopodia form and extend at rates of 8.77 +/- 0.40 microns/s, until they retract again at 7.23 +/- 0.87 microns/s; (3) filopodial strands fuse either laterally or tip to the lateral side. The combination of these motion types results in enlargements, diminutions, and extinctions of filopodial polygons, and in the formation of new polygons. Moreover, there is intense and fast (5.11 +/- 0.28 microns/s) particle transport within the filopodial strands. The organization of the cytoskeleton in filopodia was examined by electron microscopy and by labeling with fluorescent-tagged phalloidin. Filopodia contain several microtubules that are often organized in a bundle. Moreover, F-actin is present within the filopodia. To characterize which of these cytoskeletal systems is involved with cell and organelle motility, we have examined cell dynamics after incubations with colchicine or cytochalasin D. The results of these pharmacological experiments provide evidence that microtubules are required for both cell and organelle motility, but that actin filaments contribute to these phenomena and are required for the structural maintenance of slender filopodia.

Animals↗
PubMed2005

Phagocytosis, endosomal/lysosomal system and other cellularaspects of macrophage activation by Canova medication.

Canova is a homeopathic medication with immunomodulatory properties, recommended for diseases where the immune system is depressed. Our research aims to study the activation of mice peritoneal macrophages when submitted to in vivo and in vitro Canova treatment. Morphological parameters and acid phosphatase activity were analyzed using light and transmission electron microscopy. Differential interference contrast microscopy, including serial time acquisition in living cells, was also performed. The results demonstrated a greater spreading ability in Canova treated macrophages, a higher phagocytic activity of non-infective microorganisms (Saccharomyces cerevisiae and Tripanosoma cruzi epimastigotes) and a tendency to lower the phagocytic activity of the infective microorganisms T. cruzi trypomastigotes and Leishmania amazonensis, when compared with control cells. Acid phosphatase activity was analyzed and showed that Canova treatment stimulates an increase of the endosomal/lysosomal system. Treated macrophages that do or do not interact with yeast present a higher number of acid phosphatase marked vesicles compared to control cells. In contrast, the activity of tartrate resistant acid phosphatase (TRAP), is lower in Canova treated macrophages. The net results demonstrate that Canova medication is an effective stimulator of macrophage activity.

Acid Phosphatase↗
PubMed2003

Effect of acyl chain mismatch on the contact mechanics of two-component phospholipid vesicle during main phase transition.

It has been recently demonstrated that acyl chain mismatch of phospholipid bilayer composed of a binary lipid mixture induces component formation on the lateral plane of the bilayer [Biophys. J. 83 (2002) 1820-1883]. In this report, the contact mechanics of unilamellar vesicles composed of binary dimyristoyl-phosphatidylcholine (DMPC)/dipalmitoyl-phosphocholine (DPPC) mixtures on fused silica and amino-modified substrates is simultaneously probed by confocal-reflectance interference contrast microscopy (C-RICM) and cross-polarized light microscopy during gel to liquid crystalline transition of the lipid bilayer. C-RICM results indicate that the average degree of vesicle deformation for DMPC-rich and DPPC-rich vesicles adhering on fused silica substrate is increased by 30% and 14%, respectively, in comparison with that in pure DMPC and DPPC vesicles. Also, lateral heterogeneity induced by acyl chain mismatch increases the average magnitude of adhesion energy in DMPC-rich and DPPC-rich vesicles of all sizes by 6.4 times and 2.3 times, respectively. Similar modulation of adhesion mechanics induced by carbon chain difference is obtained on amino-modified substrate. Most importantly, the thermotropic transition of the mixed bilayer from gel (below T(m)) to fluid phase (above T(m)) further exemplifies the effect of acyl chain mismatch on the increases of degree of vesicle deformation and adhesion energy.

1,2-Dipalmitoylphosphatidylcholine↗
PubMed1998

Hydrogen peroxide enhances phagocytic activity of ameboid microglia.

Microglia are considered to serve as a guardian of the brain. In achieving this task, they have been observed to transform into a reactive form and then an ameboid form. Several substances are implicated in the control of such behavior. We examined the effect of hydrogen peroxide on cultured microglia of ameboid form obtained from the fetal rat brain employing video-enhanced contrast-differential interference contrast microscopy. Microglia harvested from the culture bottle were observed to float in a spherical shape with abundant filopodia on the surface. However, on coming into contact with the glass surface of a cover slip, they immediately transformed into an ameboid form. The microglia spread themselves out, surrounded by thin transparent lammellipodia, which would not be clearly observable by either light microscopy or electron microscopy. In a concentration-dependent fashion, 10(-3)-10(-1) M hydrogen peroxide solution enhanced the ruffling process of the lamellipodia and formation of vesicles (phagosomes), which displayed a typical phagocytotic form. It is concluded that an increase in free radicals in ischemic tissue tends to facilitate the phagocytosis of ameboid microglia as macrophages.

Animals↗
PubMedDate not supplied

Adhesion dynamics, morphology, and organization of 3T3 fibroblast on chitosan and its derivative: the effect of O-carboxymethylation.

Chitosan and O-carboxymethylchitosan (OCMCS) have been proved to have biocompatibility and have been extensively researched in the field of biomaterials. In this study, Confocal-reflectance interference contrast microscopy (C-RICM) in conjunction with phase contrast imaging was used to investigate the adhesion contact dynamics of 3T3 fibroblasts on chitoan and OCMCS surface-modified silica coverslips. The C-RICM results demonstrate that the weak cell contact forms on OCMCS surface while a much stronger contact area forms on the chitosan surface. 3T3 fibroblasts are found to spread randomly with spindlelike morphology on the chitosan surface, while they exhibit elongated morphology and align on the OCMCS surface. It is believed that fibroblast behaviors such as migration, spreading with an elongated morphology, and alignment on the OCMCS surface are correlated with the weak cell contact. The mechanisms to form cell adhesion contact on chitosan and OCMCS were discussed.

3T3 Cells↗
PubMed1999

Tauroursodeoxycholic acid enhances phagocytosis of the cultured rat Kupffer cell.

BACKGROUND: Ursodeoxycholic acid is used in the treatment of acute and chronic intrahepatic cholestasis because it ameliorates cholestasis and protects hepatocytes. However, few studies have examined the effect of bile acids on the function of Kupffer cells. METHODS: The effect of various bile acids on cultured rat Kupffer cells was studied in terms of phagocytic activity in response to latex particles and morphological alterations. Video-enhanced differential interference contrast microscopy was used. RESULTS: Taurochenodeoxycholic acid and taurodeoxycholic acid reduced the number of latex particles incorporated into Kupffer cells, but taurocholic and tauroursodeoxycholic acids enhanced phagocytosis of latex particles. Inhibition of phagocytosis by taurochenodeoxycholic acid or taurodeoxycholic acid was essentially dose dependent. Tauroursodeoxycholic acid also enhanced phagocytosis by Kupffer cells in which phagocytosis had been reduced by pretreatment with taurochenodeoxycholic acid or taurodeoxycholic acid. Incorporated latex particles had a distinct translocation speed of 0.084+/-0.024 microm/s (mean maximum speed+/-SD); the speed was in the same range with tauroursodeoxycholic acid treatment. Tauroursodeoxycholic acid induced a 56% expansion of cytoplasm, associated with increased ruffling and movement of intracellular organelles. CONCLUSIONS: These observations suggest that tauroursodeoxycholic acid enhances membrane trafficking without changing translocation speed.

Animals↗
PubMed1986

Invasive behaviour of mouse primordial germ cells in vitro.

We have isolated migrating primordial germ cells (PGCs) from 10.5-day mouse embryos and studied their behaviour when cultured on a mouse embryo fibroblast (STO) cell line. Living and fixed PGCs were identified by fluorescent labelling with a monoclonal antibody specific for PGCs in the culture system used. The behaviour of the cells was studied using interference reflexion microscopy (IRM) and time-lapse video cinematography. The IRM pattern displayed by PGCs is typical of highly motile cell types, the cells lack focal contacts and possess large areas of close contacts indicative of weak membrane to substrate interaction. The PGCs exhibit relatively high rates of translocation and lack contact inhibition. They were observed to underlap STO cells in subconfluent monolayers and to penetrate between the cells of confluent monolayers, becoming located between the monolayer and its substrate. These observations support the hypothesis that migrating mouse PGCs are inherently motile and are able transiently to disrupt the adhesion of surrounding cells. These results suggest that PGCs actively migrate to the developing gonad in vivo.

Animals↗
PubMed1989

Colony-stimulating factor-1 induces rapid behavioural responses in the mouse macrophage cell line, BAC1.2F5.

The cloned, SV40-immortalized mouse macrophage cell line, BAC1.2F5, resembles primary macrophages in its dependence on colony-stimulating factor-1 (CSF-1) for both viability and proliferation. Re-addition of CSF-1 stimulates rapid, transient behavioural changes in starved cells, which are rounded, with diffusely organized F-actin and few intracellular vesicles. Within 1 min, cells begin to spread, forming prominent, F-actin-rich ruffles. Small vesicles (0.5-1.0 microns), formed throughout extending lamellar processes, move centripetally and, after 3-5 min, fuse to form larger vesicles (2.0-4.0 microns), clustered around the nucleus. Immunofluorescence demonstrates that CSF-1, bound to cell-surface receptors, is internalized via these vesicles. Cell spreading and ruffling peak about 5 min after restimulation. Interference reflection microscopy indicates no corresponding change in the mode of cell-substratum adhesion: a single area of close adhesion underlies most of the cell and simply broadens during spreading. Analysis of cell aggregation kinetics shows no effect of CSF-1 on intercellular adhesiveness. Measurement of cell areas after starvation and restimulation demonstrates quantitatively the time-course and concentration-dependence of cell spreading. Mean area doubles within 5 min and, after a transient peak, decreases within 30 min to the value measured before starvation. This time-course corresponds to that of CSF-1 internalization and of the phosphorylation and subsequent degradation of CSF-1 receptors. The concentration-dependence of the spreading response resembles that of CSF-1-dependent survival and proliferation. The minimum detectable stimulation of spreading occurs at the concentration (22 pM) that supports survival without proliferation. Increasing stimulation of spreading occurs over the range of concentrations that elicit increasing proliferation.

Actins↗
PubMed1995

The traffic of particles in the axonic process of vertebrate cone-type photoreceptor cells.

Differential-interference-contrast microscopy with video enhancement displayed the movement of particles for the first time in the isolated axonic process of cone-type photoreceptor cells of Rana catesbiana. This movement was observed under visible light which visual pigments could absorb. The number of retrograde moving particles in an arbitrary area on the axonic process was twice that of those moving in the anterograde direction. The mean velocities were 1.03 +/- 0.55 microns/sec for anterograde particles and 0.41 +/- 0.30 microns/sec for retrograde particles, which are of the same order as those found in isolated neurons.

Animals↗
PubMedDate not supplied

Endonasal sinus surgery improves mucociliary transport in severe chronic sinusitis.

A total of 22 patients with extensive chronic sinusitis were examined before and 7.2 +/- 1.1 months after microscopic endonasal sinus surgery. Pre- and postoperative nasal mucociliary transport was measured using a modified saccharine test and ciliary beat frequency of nasal respiratory cells using video interference contrast microscopy. In patients suffering from chronic sinusitis, nasal ciliary beat frequency was significantly lower (8.0 +/- 1.8 Hz) than in normals (9.5 +/- 1.7 Hz p < 0.02). Following endonasal sinus surgery, ciliary beat frequency in patients with chronic sinusitis remained reduced (8.3 +/- 1.2 Hz). Nasal mucociliary transport time was significantly (p < 0.05) longer (20.9 +/- 9.4 minutes) in patients with chronic sinusitis than in normals (14.9 +/- 8.4 minutes). Nasal mucociliary transport improved significantly (p < 0.05) to 13.8 +/- 8.4 minutes in 17 of 22 patients without recurrent sinusitis and remained prolonged (20.6 +/- 7.7 minutes) in 5 of 22 patients with recurrent disease. These data suggest that ciliary beat frequency of nasal respiratory cells and nasal mucus transport are impaired in patients suffering from chronic sinusitis. After microscopic endonasal sinus surgery, impaired mucociliary transport is improved, and ciliary beat frequency remains lower than in normals.

Adult↗
PubMedDate not supplied

In vitro low frequency electromagnetic field effect on fast axonal transport.

The objective of this study was to evaluate the effects of a low frequency electromagnetic field on fast axonal transport for future neuroprosthetic applications. Changes in speeds and densities of retrograde fast organelle transport in rat sciatic nerve preparations were measured in vitro upon exposure to 15 and 50 Hz pulsed magnetic fields with peak intensities of 4.4 and 8.8 mT. Maximum current density of the induced eddy current was calculated to be about 40 microA/cm2. Video enhanced differential interference contrast microscopy was used to record axons supporting active organelle transport. Strong effects were observed in myelinated axons (cessation of transport in up to 10 min). Such effects may eventually be used as part of a neuroprosthesis to noninvasively modify or couple to various parts of the nervous system.

Animals↗
PubMed1974

Cytologic studies of hematopoietic cells by interference contrast (Nomarski) optics.

Nucleoli and other cytologic structures of mature and immature, normal and leukemic hematopoietic cells can be readily and clearly visualized when such material is examined by interference contrast microscopy. Optimum results are dependent upon the use of fresh, unfixed, unstained, briefly dried blood or bone marrow smears mounted in isotonic or near isotonic solutions of low refractive index. By this approach, fixation artifacts are avoided and cellular structures can be seen which may not be visible by any other technic. The methodology and findings, particularly with relation to nucleoli of normal and leukemic leukocytes, are discussed.

Blood Cells↗
PubMed1994

Rapid sprouting of filopodia in nerve terminals of chromaffin cells, PC12 cells, and dorsal root neurons induced by electrical stimulation.

Rapid morphological changes induced by direct electrical stimulation of nerve terminals were studied by using video-enhanced differential interference contrast microscopy at a very high magnification (12,000x). We used mainly cultured bovine chromaffin cells, which developed neurite-like processes, and PC12 cells, which showed neuronal differentiation upon NGF treatment. In a few cases, primary neurons of the rat dorsal root ganglion were also examined. Brief pulse stimulation of the terminals and varicosities induced exocytosis accompanied by rapid formation of filopodia. These filopodia, 0.1-0.2 micron in diameter and up to 10 microns in length, formed within a few hundreds of milliseconds and then retracted within tens of seconds. They could also be induced by K depolarization. This rapid filopodial sprouting strongly depended on the presence of extracellular Ca2+ and could be abolished in a medium containing a Ca chelator (EGTA) or La2+. Anti-cytoskeletal agents colchicine and cytochalasin B failed to block this response completely but lidocaine fully suppressed it. Quantitative analysis of exocytosis and filopodial sprouting showed that they were independent events, not directly linked to each other, having different thresholds usually higher for filopodial formation. In PC12 cells, the extent of filopodial sprouting varied with the state of differentiation of the cells, suggesting a functional role of rapid sprouting during a particular phase of their differentiation. Filopodia could be induced with greater ease by repetitive stimulation. The same responses may occur at growth cones approaching the target cells or even at mature synapses particularly after repetitive electrical activity, possibly playing a role in use-dependent synapse formation or plasticity.

Aging↗