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At least 19 recordsLinked to original sources
PubMed1996

Swift transformation and locomotion of polymorphonuclear leukocytes and microglia as observed by VEC-DIC microscopy (video microscopy).

The detailed assembly used by us for video-enhanced contrast-differential interference contrast (VEC-DIC) microscopy (video microscopy is first described. Employing such video microscopy, we then examined the morphological changes occurring during locomotion and activation processes of polymorphonuclear leukocytes (PMNL) and microglia at an almost electron microscopic magnification. Upon contacting the substratum, PMNL transformed into a polarized ameboid shape and crawled extending pseudopodia, as has been well documented previously. The PMNL sometimes displayed a peculiar locomotion as if they were stepping on "tiny legs", or sliding on a treadmill of cell membrane. Cultured microglia were observed to exist in 4 forms; ramified, reactive, villous, and ameboid. Microglia in the reactive form pivoted, circled and crawled on the astroglial cell layer using their transparent lamellipodia with no morphological changes in their cell body. Unlike PMNL, reactive microglia exhibited no agitated movements of their intracellular organelles, including granules and cytosol, during locomotion. Lamellipodia on the undersurface of the cell body touching the cell layer adhesively, appeared to serve as the locomotive apparatus. When activated, both floating PMNL and microglia of villous form assumed an ameboid shape within a few seconds. Microglia occasionally swam in the medium waving their lamellipodia towards a target object (e.g. zymosan A particles), remodelling to an amorphous ameboid form and covering up the target. We attempt to discuss such swift morphological changes from the standpoint of thermodynamic potential of Gibbs free energy which is stored within the cells.

Cell Movement↗
PubMed1993

Ischemia-reperfusion induced microvascular dysfunction in skeletal muscle: application of intravital video microscopy.

Video microscopy of red cell flow in capillaries at the surface of skeletal muscle provided the opportunity to quantitate ischemia-reperfusion (I-R) induced microcirculatory changes, in vivo. Extensor Digitorum Longus (EDL) muscles of 22 male Wistar rats (300-400 g), anesthetized with sodium pentobarbital (Somnotol, 65 mg kg,-1 IP), were used to measure the number of perfused capillaries (CDper: mm-1) crossing lines drawn perpendicular to the muscle axis, and red blood cell velocity (VRBC: mm/s) within individual capillaries from controls (n = 6), and after 2 hr (n = 4), 3 hr (n = 4), and 4 hr (n = 5) of no-flow ischemia with the muscle temperature maintained at its normal value of 32 degrees C. Ischemia was induced by tightening a tourniquet placed around the limb above the EDL muscle. Measurements were made after 30, 60, and 90 min of reperfusion. To test the usefulness of this skeletal muscle model for evaluating proposed interventions in I-R, the effect of hypothermia (24 degrees C) on the microcirculation following 4 hr ischemia (n = 3) was measured. Edema formation was estimated from the wet/dry weight ratio of the ischemic and contralateral control EDL muscles. Capillary perfusion at the surface of the control muscles was remarkably stable over the 5 hr period studied, while significant changes occurred following the ischemic periods. Significantly lower CDper was measured 30 min following all periods of normothermic ischemia. However, unlike the 2 and 4 hr ischemic periods 3 hr normothermic ischemia resulted in a progressive decline in CDper throughout the reperfusion period. VRBC showed evidence of a hyperemic response following 2 hr normothermic ischemia (control: 0.12 mm/s +/- 0.19 compared to 0.26 mm/s +/- 0.03 following 90 min reperfusion; mean +/- sem). However, no such hyperemia was measured following either 3 or 4 hr normothermic ischemia (i.e., 3 hr control: 0.24 mm/s +/- 0.01 compared to 0.07 mm s +/- 0.003 following 90 min reperfusion). In fact, VRBC was essentially zero 90 min following 4 hr normothermic ischemia (0.01 mm/s +/- 0.01). However, when the muscle was allowed to cool to 24 degrees C during 4 hr ischemia no significant change in either VRBC or CDper was measured compared to pre-ischemic controls. Evidence of edema was found after 3 and 4 hr normothermic ischemia. This study establishes a skeletal muscle model of I-R, which may be useful in testing hypotheses regarding mechanisms of I-R injury, and effectiveness of proposed treatments of I-R.

Animals↗
PubMed1994

Detection of minute intestinal metaplastic lesions by video microscopy.

Using video microscopy in 225 resected stomachs we detected 32 minute solitary lesions of intestinal metaplasia histologically. The magnified features of the minute lesions showed a characteristic appearance and were classified into three types: mesh-like (type A), villoid (type B), and tubular (type C). All the lesions classified as type A exhibited the incomplete type of intestinal metaplasia according to the results of histopathological and/or histochemical examination. In contrast, most lesions classified as type B exhibited the complete type of intestinal metaplasia. We concluded that intentional detection of minute lesions in resected stomachs by video microscopy is simple and useful, especially in cases of minute lesions < 5 mm in diameter. Moreover, our findings demonstrate that the minute intestinal metaplastic lesions have morphological characteristics based on which they can be classified into three types of lesions. These morphological characteristics correlate with their histopathological findings.

Adult↗
PubMed1992

Direct detection of immunogold reactions by real-time video microscopy.

Video-enhanced microscopy allows the detection and tracking of individual colloidal gold particles. The analysis of immunogold reactions can also be conducted as a function of time and thus allows the study of dynamic events in living cells. The direct visualization in real time is reported of the reaction of immunogold particles with a surface antigen. This time-resolved immunocytochemistry was achieved by continuous observation of living cells infected with a virus (respiratory syncytial virus) following their incubation with colloidal gold (30 nm) coated with antiviral antibodies. The progress of the immunoreaction was visualized as a sequential deposition of individual gold granules on the viral particles until saturation was reached after 60 min. Binding of colloidal gold was an irreversible event as no elution or dislocation of surface-bound granules took place. Comparative imaging of colloidal gold particles by electron microscopy and by video microscopy demonstrated that the video-imaged immunoreactions represented events involving single gold particles; their signal was sometimes clearly enhanced by secondary depositions taking place in close proximity, i.e. at a distance below the lateral resolution of the light microscope. Our experiments demonstrate that video-enhanced microscopy provides a powerful tool for studying antibody-antigen reactions with a high spatial and temporal resolution.

Animals↗
PubMed1994

Tacalcitol in psoriasis: a video-microscopy study.

Video-microscopy is a video-imaging system which permits direct visualization of the skin surface and capillaries, by using a microscope attached to a camera, a video-recorder and a printer. This technique provides information on the morphology of capillaries in vivo and has been used both for research into normal skin microcirculation and as a clinical method to detect capillary changes in psoriasis and other skin diseases. The aim of this study was to evaluate the morphology of capillaries in psoriatic plaques before and after treatment with tacalcitol, a new topical vitamin D3 analogue. Clinical evaluation was made after 3 and 6 weeks of therapy. After 3 weeks a reduction in erythema and scaling was noted; and areas in which capillaries were less tortuous became evident. After 6 weeks, capillaries were less dilated and tortuous in the whole plaque and had lost the large and tortuous appearance of active psoriasis.

Adult↗
PubMed1988

Progress in video microscopy.

The progress in video microscopy is reviewed from its early inception, especially with respect to improvements of the microscope image quality. Very recent advances that provide serial optical sections and depth of field as thin as 0.1 micron and that make possible the recording of birefringent images of individual microtubules (25 nm in diameter) directly in live, dividing cells are also documented.

Animals↗
PubMed2004

Aggregation and breakup of colloidal particle aggregates in shear flow, studied with video microscopy.

We used video microscopy to study the behavior of aggregating suspensions in shear flow. Suspensions consisted of 920 nm diameter silica spheres, dispersed in a methanol/bromoform solvent, to which poly(ethylene glycol) (M = 35.000 g) was added to effect weak particle aggregation. With our solvent mixture, the refractive index of the particles could be closely matched, to allow microscopic observations up to 80 microm deep into the suspension. Also the mass density is nearly equal to that of the particles, thus allowing long observation times without problems due to aggregate sedimentation. Particles were visualized via fluorescent molecules incorporated into their cores. Using a fast confocal scanning laser microscope made it possible to characterize the (flowing) aggregates via their contour-area distributions as observed in the focal plane. The aggregation process was monitored from the initial state (just after adding the polymer), until a steady state was reached. The particle volume fraction was chosen at 0.001, to obtain a characteristic aggregation time of a few hundred seconds. On variation of polymer concentration, cP (2.2-12.0 g/L), and shear rate, gamma (3-6/s), it was observed that the volume-averaged size, Dv, in the steady state became larger with polymer concentration and smaller with shear rate. This demonstrates that the aggregate size is set by a competition between cohesive forces caused by the polymer and rupture forces caused by the flow. Also aggregate size distributions were be measured (semiquantitatively). Together with a description for the internal aggregate structure they allowed a modeling of the complete aggregation curve, from t = 0 up to the steady state. A satisfactory description could be obtained by describing the aggregates as fractal objects, with Df = 2.0, as measured from CSLM images after stopping the flow. In this modeling, the fitted characteristic breakup time was found to increase with cP.

Journal Article↗
PubMed1993

Scanning and transmission electron microscopy and high resolution intravital video-microscopy of capillaries in the mouse exocrine pancreas, with special emphasis on endothelial cells.

Capillaries in the mouse exocrine pancreas were studied by scanning electron microscopy of microvascular corrosion casts, transmission electron microscopy of tissue sections, and high resolution intravital video-microscopy. Two types of capillaries were discerned by corrosion casting. The first type was rather straight, had a constant diameter of 5-6 microns, and its surface showed multiple circumferential furrows. The frequency of such constrictions was less in the second type, which was more undulated and had a diameter of 7-9 microns. In the second type, these constrictions defined bulged areas of the capillary cast. Corresponding tissue sections also showed two types of capillaries, fenestrated and non-fenestrated capillaries. Microtubules were abundant in all capillary endothelial cells, whereas bundles of microfilaments were scarce. Microtubules were arranged along the long axis of endothelial cells as well as parallel to endothelial cell border regions. Endothelial cells were joined by intermediate junctions along cell borders running both circumferentially and longitudinally. Flow reversal in capillaries and spontaneous endothelial contractions were documented in vivo. Endothelial cells bulged into the lumen, either at their nuclear region or distant from it. Spontaneous contraction of pericytes was not observed. These results suggest that contraction of capillaries is carried out by endothelial cells, representing an autonomous flow regulatory device. Capillary contraction in exocrine pancreas may be influenced by blood-borne agents, probably by those released in Langerhans islets.

Animals↗
PubMed1992

Human performance studies of the video microscopy component of a dynamic telepathology system.

Human performance studies were performed to evaluate the video microscopy component of a proposed dynamic telepathology system. Frozen sections from breast biopsies of 115 patients were evaluated by both conventional light microscopy and video microscopy by 6 pathologists. Receiver operator characteristic (ROC) curve studies showed nearly identical levels of discrimination between benign and malignant breast lesions for both viewing modalities. Viewing times were significantly greater (p < 0.001) for video microscopy but within a time frame that rendered the technology of potential value for pathology diagnostic applications. Large degrees of interobserver viewing time variability were found for light and video microscopy.

Biopsy↗
PubMed2003

Chronology of cellular alterations during 7-ketocholesterol-induced cell death on A7R5 rat smooth muscle cells: analysis by time lapse-video microscopy and conventional fluorescence microscopy.

BACKGROUND: Time-lapse video microscopy was used to determine whether mitochondrial and nuclear changes (decrease in mitochondrial transmembrane potential, condensation, and/or fragmentation of the nuclei, morphologic features typical of apoptosis) occurring during 7-ketocholesterol-induced cell death on A7R5 rat smooth muscle cells took place before or after the loss of cell adhesion. In addition, changes in actin organization were followed by conventional fluorescence microscopy. METHODS: Morphologic, functional, and spatial changes at the mitochondrial level were investigated with 3,3'-dihexyloxacarbocyanine iodide and/or MitoTracker Red, and nuclear morphology was characterized by staining with Hoechst 33342. Actin fibers, which are major components of the filament network of the cytoskeleton, were visualized with phalloidin linked to fluorescein. The numbers of adherent and nonadherent cells were determined by cell counting. RESULTS: 7-Ketocholesterol-induced cell death was associated with a rapid alteration of actin fibers, a loss of intercellular junctions, and cell shape modifications. Analysis of mitochondrial transmembrane potential showed successively a hyperpolarization and a more or less pronounced progressive decrease followed by a dramatic drop associated with an increase in Hoechst 33342 staining, reflecting chromatin condensation and morphologic changes in the nuclei. CONCLUSIONS: During cell death induced by 7-ketocholesterol in A7R5 rat smooth muscle cells, the different methods of microscopy allowed us to establish that alterations of actin fibers and mitochondrial dysfunctions occurred before condensation and/or fragmentation of the nuclei, which preceded the loss of cell adhesion.

Actins↗
PubMed1992

The validity of frozen section diagnosis based on video-microscopy.

To investigate the accuracy of video-microscopy of frozen sections, two pathologists reexamined 80 cases of archival material, on which frozen sections had previously been performed. Diagnoses based on the two trials (Observer 1 and 2) and diagnoses obtained in the original frozen section situation were compared with the final diagnoses based on paraffin embedded material. Observer 1 had two false negative diagnoses, but no false positive, whereas Observer 2 had one false positive, but no false negative diagnosis when compared with the final diagnoses. No false positive or false negative diagnoses were made in the original frozen sections situation and the number of inconclusive diagnoses were 5, as compared with 6 and 8 in the two trials based on video-microscopy. More experience with video-microscopy will probably achieve a quality of frozen section diagnoses similar to that of direct light-microscopy.

Diagnosis, Differential↗
PubMed1993

Analysis of lymphocyte activation and proliferation by video microscopy and digital imaging.

Video microscopy and digital imaging were used as a noninvasive method to quantitatively analyze lymphocyte activation and proliferation. This method takes advantage of the fact that upon activation lymphocytes blast and become significantly larger before proliferating. The mean cell sizes of T lymphocytes in an activation kinetics assay were measured by digital image analysis and compared to [3H]-thymidine incorporation of cells under the same treatment. An increase in cell size was observed before [3H]-thymidine incorporation; therefore the digital imaging assay is more sensitive in determining the earliest time-point of activation. Also, the digital imaging assay was comparable to the [3H]-thymidine incorporation assay in providing information about the extent and rates of T lymphocyte proliferation. Cellular DNA was stained with propidium iodide to show that the larger blasting cells in the population of activated T lymphocytes were indeed the cells that accounted for the increase in DNA synthesis and thus an increase in cell size can be correlated with activation.

Analog-Digital Conversion↗
PubMed2002

A new abdominal cavity chamber to study the impact of increased intra-abdominal pressure on microcirculation of gut mucosa by using video microscopy in rats.

OBJECTIVE: In experimental studies of capillary blood flow that use intravital video microscopy, organs are exposed in observation chambers implanted into the animal. In this article we describe an abdominal cavity chamber for intravital video microscopy of gut mucosa microcirculation during increased intra-abdominal pressure. DESIGN: Prospective, experimental animal study. SETTING: Research laboratory at a university hospital. SUBJECTS: Male Wistar rats. INTERVENTIONS: The abdominal cavity chamber was designed for implantation into the abdominal wall of rats after laparotomy, thus creating an expanded hermetic, abdominal cavity volume. Animals were assigned to three levels of intra-abdominal pressure: controls (group 1), 10 mm Hg (group 2), and 15 mm Hg (group 3). Intra-abdominal pressure was increased by intra-abdominal insufflation of gas. By using a fluorescent marker, we quantitatively assessed mucosa perfusion index, functional capillary density, red blood cell velocity, capillary diameters, and flow motion during increased intra-abdominal pressure by intravital video microscopy. Results were expressed as mean +/- SEM. Significance of differences was determined by analysis of variance and multiple comparison of means with post hoc test (*p <.05 groups vs. control;p <.05 group 3 vs. group 2). MEASUREMENTS AND MAIN RESULTS: When compared with controls, animals subjected to an intra-abdominal pressure of 10 and 15 mm Hg showed a significant stepwise decrease in mucosa perfusion index (88%, 71%*, 22%*), functional capillary density (665.4 +/- 71.7, 461.6 +/- 71.9*, 375.1 +/- 2.0*cm(-1)), and red blood cell velocity (0.50 +/- 0.04, 0.33 +/- 0.03*, 0.04 +/- 0.06*mm/sec), indicating a stepwise impairment of mucosal microcirculation. Capillary diameters and flow motion did not change with respect to intra-abdominal pressure. CONCLUSIONS: This novel animal model of intravital intestinal video microscopy that uses an abdominal cavity chamber is a feasible and sensitive experimental tool to study intestinal microcirculation during increased intra-abdominal pressure. Intra-abdominal pressure likely results in a severe impairment of mucosal microcirculation.

Abdomen↗
PubMed2006

Structure and locomotion of adult in vitro regenerated spiral ganglion growth cones-- a study using video microscopy and SEM.

Neuronal development and neurite regeneration depends on the locomotion and navigation of nerve growth cones (GCs). There are few detailed descriptions of the GC function and structure in the adult auditory system. In this study, GCs of adult dissociated and cultured spiral ganglion (SG) neurons were analyzed in vitro utilizing combined high resolution scanning electron microscopy (SEM) and time lapse video microscopy (TLVM). Axon kinesis was assessed on planar substratum with growth factors BDNF, NT-3 and GDNF. At the nano-scale level, lamellipodial abdomen of the expanding GC was found to be decorated with short surface specializations, which at TLVM were considered to be related to their crawling capacity. Filopodia were devoid of these surface structures, supporting its generally described sensory role. Microspikes appearing on lamellipodia and axons, showed circular adhesions, which at TLVM were found to provide anchorage of the navigating and turning axon. Neurons and GCs expressed the DCC-receptor for the guidance molecule netrin-1. Asymmetric ligand-based stimulation initiated turning responses suggest that this attractant cue influences steering of GC in adult regenerating auditory neurites. Hopefully, these findings may be used for ensuing tentative navigation of spiral ganglion neurons to induce regenerative processes in the human ear.

Adult↗
PubMed1992

Brain microtubule-associated proteins modulate microtubule dynamic instability in vitro. Real-time observations using video microscopy.

We used video assays to study the dynamic instability behavior of individual microtubules assembled in vitro with purified tau, purified MAP2 or a preparation of unfractionated heat-stable MAPs. Axoneme-nucleated microtubules were assembled from pure tubulin at concentrations between 4 and 9 microM in the presence of MAPs, and observed by video-differential interference contrast microscopy. Microtubules co-assembled with each MAP preparation exhibited the elongation and rapid shortening phases and the abrupt transitions (catastrophe and rescue) characteristic of dynamic instability. Each MAP preparation increased the microtubule elongation rate above that for purified tubulin alone by decreasing the tubulin subunit dissociation rate during elongation. The brain MAPs used in this study reduced the rate of microtubule rapid shortening, but allowed significant loss of polymer during the shortening phase. Purified tau and MAP2 decreased the frequency of catastrophe and increased the frequency of rescue, while the heat-stable MAPs suppressed catastrophe at all but the lowest tubulin concentrations. Thus, each of these MAPs modulates, but does not abolish, dynamic instability behavior of microtubules. We propose a model to explain how MAP2 and tau bind to the microtubule lattice at sites along protofilaments so that the MAPs promote polymerization, but do not significantly block the mechanism of rapid shortening inherent in the tubulin lattice. Rapid shortening, when it occurs, proceeds primarily by the dissociation of short fragments of protofilaments, which contain the bound MAPs.

Animals↗
PubMed2002

Video-microscopy observations of fast dynamic processes in the protozoon Giardia lamblia.

Video-microscopy in combination with digital image processing was used to analyze dynamic processes associated to the life cycle of Giardia lamblia trophozoites. These parasites swim and attach to the epithelial cells, producing the disease known as Giardiasis. Giardia is a multiflagellar cell, presenting 4 pairs of flagella. With the use of analogue and digital tools, we observed that in cells attached to glass slides only 2 of the 4 pairs present active beating (wave propagation). The frequency observed was 17-18 Hz to the anterior and 8-11 Hz to the ventral flagella. These data resulted from several hours of recording using both analogue video and high-speed digital camera. The caudal pair did not show active beating patterns and the same holds true for the posterior one. In this latter pair, oscillations were observed, but they were always associated to the transit of the wave produced by the ventral pair. The analysis performed with free moving cells showed that during its forward dislocation, Giardia lamblia presented either a lateral rocking or a complete rotational (tumbling) movement around its longitudinal axis. A dislocation of the caudal region of the cell both in the lateral and dorso-ventral direction was observed. This movement was completely independent from the flagellar beating and it is likely to be produced by a microtubular complex located in the caudal portion of the cell. The adhesion process of Giardia lamblia was also followed by video-microscopy and the data showed that the ventral disk had an active participation in this process.

Animals↗