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PubMed1991

Video-nailfold-microscopy and local cold test: morphological and hemodynamic correlates in 124 healthy subjects.

Video-nailfold-microscopy in combination with a local cooling test were used to determine morphological and hemodynamic reference values with their variabilities such as sex, age, blood pressure and smoking habits in 124 healthy volunteers. In our non-smoking population (n = 90) neither arterial blood pressure nor age or the sex of the subjects had any significant influence on the morphological or hemodynamic parameters, even after the local cooling test. However, cooling the skin caused in all cases a rapid, temporary decrease in the velocity of blood flow through the capillaries. The small group of chronic smokers (n = 34) showed no sex differences in any of the measured variables even when compared with sex and age matched non-smokers. It may be concluded that video-capillaroscopy, a non-invasive technique, can be used in clinical practice for studying the physiology and pathophysiology as well as the dynamic response to local cooling in microcirculatory diseases of the human skin.

Adult↗
PubMed1985

Histopathological comparison of the effects of hematoporphyrin derivative on two different murine tumors using computer-enhanced digital video fluorescence microscopy.

A comparison study of the effects of hematoporphyrin derivative (HPD) photoradiation therapy on two different mouse sarcoma tumor model systems (RIF-1 + EMT-6) was performed. Twenty-four h after i.v. administration of HPD, the responses to total laser light doses of 50-400 J/cm2 were evaluated by histological examination and the uptake and distribution of HPD using a computer enhanced digital video fluorescence microscopy technique. In response to total laser light dose (630 nm) of 50-400 J/cm2, 40 mice with RIF-1 tumor showed only minimal superficial tumor necrosis upon histological examination and a 9-12% increase in maximal tissue fluorescence. In contrast, 40 mice with EMT-6 tumor showed marked areas of patchy coagulation necrosis and vascular hemorrhage at doses as low as 50 J/cm2 and essentially total tumor destruction at total light doses of 150 J/cm2 or more. A 59-74% increase in maximal tissue fluorescence was observed using digital video fluorescence microscopy. It is concluded that the greater efficacy of treatment in the EMT-6 tumor as compared to the RIF-1 tumor was due to the greater localization of HPD as demonstrated by digital video fluorescence microscopy.

Animals↗
PubMed1999

A new perfusion cell chamber system for determination of heat shock effects by means of video-enhanced microscopy.

A user friendly microscope perfusion chamber which allows real-time observation of individual cells at high magnification has been designed. An integrated multisensor was used to monitor the cell culture conditions. To prove the potential of the system heat shock experiments were performed. By means of video-enhanced contrast microscopy (VECM) the mitochondria morphology of cultured astrocytes was demonstrated to change from a rod-like to an annular shape after heat shock. For further analyses mitochondria were stained on the microscope stage.

Animals↗
PubMed1978

The visualization of fluorescent proteins in living cells by video intensification microscopy (VIM).

A highly sensitive television camera (silicon intensifier target) has been combined with fluorescence microscopy to examine living cultured cells. This system is termed Video Intensification Microscopy (VIM). By using very small amounts of excitation light, one limits the damage to living cells from excessive illumination and is able to visualize fluorescence probes for periods up to 24 hr without bleaching. With VIM, the cellular uptake and fate of two rhodamine-labeled proteins, concanavalin A and alpha2 macroglobulin, have been followed for up to 24 hr. These proteins were first located in endocytic vesicles with a low phase density. Later, at 24 hr, alpha2 macroglobulin was located in phase-dense structures, probably secondary lysosomes. Both the fluorescent endocytic vesicles and lysosomes were observed to undergo saltatory motion. VIM combined with fluorescence promises to have a widespread application in the study of the behavior of living cells.

Cell Line↗
PubMed1995

Differences in dispersion of influenza virus lipids and proteins during fusion.

Digitally enhanced low-light-level fluorescence video microscopy and immunochemical staining were used to examine influenza virus envelope lipid and protein redistribution during pH-induced fusion. Video microscopy was performed using viruses labeled with either the lipid analogue octadecylrhodamine B (R18) or fluorescein isothiocyanate (FITC) covalently linked to envelope proteins. Viruses were bound to human red blood cells, and the pattern and intensity of fluorescence were monitored for 30 min while cell-virus complexes were perfused with pH 7.4 or 4.8 media at temperatures either above or below 20 degrees C. R18 showed complete redistribution and dequenching by 30 min at all incubation temperatures, confirming reports that viral fusion occurs at subphysiological temperatures. FITC-labeled protein showed spatial redistribution at 28 degrees C but no change at low temperature. Electron microscopy observations of immunochemical staining of viral proteins confirmed both that protein redistribution at 37 degrees C was slower than R18 and the failure of movement within 30 min at 16 degrees C. Video microscopy monitoring of RNA staining by acridine orange of virus-cell complexes showed redistribution to the RBCs at all temperatures but only after low pH-induced fusion. The results are consistent with differential dispersion of viral components into the RBC and the existence of relatively long-lived barriers to diffusion subsequent to fusion pore formation.

Animals↗
PubMed2000

An integrated laser trap/flow control video microscope for the study of single biomolecules.

We have developed an integrated laser trap/flow control video microscope for mechanical manipulation of single biopolymers. The instrument is automated to maximize experimental throughput. A single-beam optical trap capable of trapping micron-scale polystyrene beads in the middle of a 200-microm-deep microchamber is used, making it possible to insert a micropipette inside this chamber to hold a second bead by suction. Together, these beads function as easily exchangeable surfaces between which macromolecules of interest can be attached. A computer-controlled flow system is used to exchange the liquid in the chamber and to establish a flow rate with high precision. The flow and the optical trap can be used to exert forces on the beads, the displacements of which can be measured either by video microscopy or by laser deflection. To test the performance of this instrument, individual biotinylated DNA molecules were assembled between two streptavidin beads, and the DNA elasticity was characterized using both laser trap and flow forces. DNA extension under varying forces was measured by video microscopy. The combination of the flow system and video microscopy is a versatile design that is particularly useful for the study of systems susceptible to laser-induced damage. This capability was demonstrated by following the translocation of transcribing RNA polymerase up to 650 s.

Calibration↗
PubMed1982

Digitized video fluorescence microscopy studies of adriamycin interaction with single P388 leukemic cells.

We have evaluated a new fluorescent method, the digitized video fluorescence microscopy technique, for the analysis of Adriamycin drug levels in single-cell suspension. This method uses a Leitz microscope equipped with an HBO 50 watt mercury source; the vertical body of the microscope is attached to an intensified silicone intensifier video camera with its output coupled to a video cassette recorder and to an Apple II microcomputer equipped with a video image digitizer. Using this technique, we were able to corroborate previous findings of decreased uptake and increased efflux in resistant as compared to sensitive P388 leukemic cells. This instrument may have wide applications in the study of anthracycline cell interaction or of any other drug with fluorescent properties.

Adsorption↗
PubMed2005

Differences in morphology of phagosomes and kinetics of acidification and degradation in phagosomes between the pathogenic Entamoeba histolytica and the non-pathogenic Entamoeba dispar.

Phagocytosis plays an important role in the pathogenicity of the intestinal protozoan parasite Entamoeba histolytica. We compared the morphology of phagosomes and the kinetics of phagosome maturation using conventional light and electron microscopy and live imaging with video microscopy between the virulent E. histolytica and the closely-related, but non-virulent E. dispar species. Electron micrographs showed that axenically cultivated trophozoites of the two Entamoeba species revealed morphological differences in the number of bacteria contained in a single phagosome and the size of phagosomes. Video microscopy using pH-sensitive fluorescein isothiocynate-conjugated yeasts showed that phagosome acidification occurs within 2 min and persists for >12 h in both species. The acidity of phagosomes significantly differed between two species (4.58 +/- 0.36 or 5.83 +/- 0.38 in E. histolytica or E. dispar, respectively), which correlated well with the differences in the kinetics of degradation of promastigotes of GFP-expressing Leishmania amazonensis. The acidification of phagosomes was significantly inhibited by a myosin inhibitor, whereas it was only marginally inhibited by microtubules or actin inhibitors. A specific inhibitor of vacuolar ATPase, concanamycin A, interrupted both the acidification and degradation in phagosomes in both species, suggesting the ubiquitous role of vacuolar ATPase in the acidification and degradation in Entamoeba. In contrast, inhibitors against microtubules or cysteine proteases (CP) showed distinct effects on degradation in phagosomes between these two species. Although depolymerization of microtubules severely inhibited degradation in phagosomes of E. histolytica, it did not affect degradation in E. dispar. Similarly, the inhibition of CP significantly reduced degradation in phagosomes of E. histolytica, but not in E. dispar. These data suggest the presence of biochemical or functional differences in the involvement of microtubules and proteases in phagosome maturation and degradation between the two species.

Actins↗
PubMed1987

Real-time visualization of oxyradical burst from single neutrophil by using ultrasensitive video intensifier microscopy.

Dynamics of oxyradical burst from single human neutrophils stimulated by opsonized zymosan was visualized by using an ultrasensitive video intensifier microscopy in the presence of chemiluminescence probe. Luminol-dependent photonic burst activities were clearly corresponding to the distribution of zymosan-treated neutrophils. Heterogeneity of photon-bursting period and the maximum photonic intensity among reactive cells was demonstrated. This may reflect functional heterogeneity of the ability to release oxyradicals among neutrophils.

Free Radicals↗
PubMed2003

Early development of fern gametophytes in microgravity.

Dormant spores of the fern Ceratopteris richardii were flown on Shuttle mission STS-93 to evaluate the effects of micro-g on their development and on their pattern of gene expression. Prior to flight the spores were sterilized and sown into one of two environments: (1) Microscope slides in a video-microscopy module; and (2) Petri dishes. All spores were then stored in darkness until use. Spore germination was initiated on orbit after exposure to light. For the spores on microscope slides, cell level changes were recorded through the clear spore coat of the spores by video microscopy. After their exposure to light, spores in petri dishes were frozen in orbit at four different time points during which on earth gravity fixes the polarity of their development. Spores were then stored frozen in Biological Research in Canister units until recovery on earth. The RNAs from these cells and from 1-g control cells were extracted and analyzed on earth after flight to assay changes in gene expression. Video microscopy results revealed that the germinated spores developed normally in microgravity, although the polarity of their development, which is guided by gravity on earth, was random in space. Differential Display-PCR analyses of RNA extracted from space-flown cells showed that there was about a 5% change in the pattern of gene expression between cells developing in micro-g compared to those developing on earth.

Cell Nucleus↗
PubMed1987

Video fluorescence microscopy studies of phospholipid vesicle fusion with a planar phospholipid membrane. Nature of membrane-membrane interactions and detection of release of contents.

Video fluorescence microscopy was used to study adsorption and fusion of unilamellar phospholipid vesicles to solvent-free planar bilayer membranes. Large unilamellar vesicles (2-10 microns diam) were loaded with 200 mM of the membrane-impermeant fluorescent dye calcein. Vesicles were ejected from a pipette brought to within 10 microns of the planar membrane, thereby minimizing background fluorescence and diffusion times through the unstirred layer. Vesicle binding to the planar membrane reached a maximum at 20 mM calcium. The vesicles fused when they were osmotically swollen by dissipating a KCl gradient across the vesicular membrane with the channel-forming antibiotic nystatin or, alternatively, by making the cis compartment hyperosmotic. Osmotically induced ruptures appeared as bright flashes of light that lasted several video fields (each 1/60 s). Flashes of light, and therefore swelling, occurred only when channels were present in the vesicular membrane. The flashes were observed when nystatin was added to the cis compartment but not when added to the trans. This demonstrates that the vesicular and planar membranes remain individual bilayers in the region of contact, rather than melding into a single bilayer. Measurements of flash duration in the presence of cobalt (a quencher of calcein fluorescence) were used to determine the side of the planar membrane to which dye was released. In the presence of 20 mM calcium, 50% of the vesicle ruptures were found to result in fusion with the planar membrane. In 100 mM calcium, nearly 70% of the vesicle ruptures resulted in fusion. The methods of this study can be used to increase significantly the efficiency of reconstitution of channels into planar membranes by fusion techniques.

Adsorption↗
PubMed2004

Extracellular matrix molecules regulate endothelial cell migration stimulated by lysophosphatidic acid.

BACKGROUND: Lysophosphatidic acid (LPA) and sphingosine 1-phosphate (S1P) are lipids that bind G-protein coupled receptors and differentially promote transmigration of endothelial cells. OBJECTIVE: To determine if endothelial cell transmigration stimulated by LPA, not S1P, is dependent on the extracellular matrix. METHODS: Bovine pulmonary artery (BPAE) endothelial cell transmigration and locomotion were measured using a modified-Boyden chamber and video microscopy, respectively. Results were related to strength of adhesion and characteristics of cell adhesive contacts. RESULTS AND CONCLUSIONS: BPAEs responded to LPA by transmigration through gelatin- or collagen-coated filters, but not through fibronectin-, vitronectin-, or fibrinogen-coated filters. Fewer cells adhered to collagen or gelatin than to fibronectin in a static cell adhesion assay or after application of a g-force to detach cells. Video microscopy revealed that S1P stimulates large lamellipodia on two-dimensional fibronectin substrate. LPA stimulated lamellipodia on fibronectin, but the trailing edge remained attached, resulting in sting ray-shaped cells in video microscopy. LPA-treated cells on gelatin released the trailing edge. To understand how the extracellular matrix may regulate endothelial cell shape during movement, we surveyed changes in focal adhesion proteins. More Hic-5, a paxillin homolog, was detected in the detergent insoluble fraction of BPAEs attached to gelatin than fibronectin. No such difference was found in paxillin. In BPAEs, Hic-5 was localized to smaller punctate structures on fibronectin and longer, thinner focal adhesions on gelatin. These results indicated that localization of Hic-5 and strength of adhesion correlate with endothelial cell transmigration stimulated by LPA, but not with transmigration stimulated by S1P.

Animals↗
PubMed1988

The rapid desensitization of receptors for platelet derived growth factor, bradykinin and ATP: studies on individual cells using quantitative digital video fluorescence microscopy.

The rise in free cytosolic Ca2+ of individual response to growth factors was studied in serum starved cultures of 3T3 fibroblasts. Quantitative digital video fluorescence microscopy revealed that with platelet derived growth factor (PDGF) there was a lag period between stimulation and Ca2+ response, with considerable cell-to-cell variation, whereas ATP, bradykinin and fetal calf serum induced an immediate, synchronous response. A coverslip with attached cells was mounted on a small flow chamber, allowing complete change of medium in 2 sec. Using this technique, homologous desensitization to a second addition of agonist 2 min after removal of the first addition was found for all agonists. Unusual heterologous desensitization was observed in that PDGF desensitized the cells to the other agonists, yet the reverse did not occur.

Adenosine Triphosphate↗
PubMed1991

Location of P-II and AlPCS4 in human tumor LOX in vitro and in vivo by means of computer-enhanced video fluorescence microscopy.

The patterns of in vitro intracellular and in vivo intratumoral localization of Photofrin II (P-II) and aluminum phthalocyanine tetrasulfonate (AlPCS4) in human melanoma LOX were studied by means of computer-enhanced video fluorescence microscopy (CEVFM). The hydrophobic drug P-II localized diffusely in the perinuclear fraction of the cytoplasm of the LOX cells cultivated in vitro. Light exposure did not result in any observable change in the localization pattern. The hydrophilic dye AlPCS4 was distributed as granular and grain patterns in the cytoplasm before light exposure, in exactly the same pattern as that of acridine orange incubated in the same cells, which is known to emit red fluorescence from lysosomes, thus indicating that AlPCS4 was also primarily localized in the lysosomes of the LOX cells. After light exposure the distribution of the intracellular AlPCS4 fluorescence was altered and the intensity increased. In vivo, P-II had a combined cellular localization pattern (i.e. a strongly cytoplasmic membrane-localizing pattern and a weakly intracellular distribution pattern) and an extracellular distribution pattern in the tumor tissue, while the AlPCS4 fluorescence was seen mainly in the stroma of the tumor. The total fluorescence intensity of P-II and AlPCS4 in the LOX tumor tissue at different times after injection was quantitatively determined by means of CEVFM.

Animals↗
PubMed1991

Actin dynamics in growth cones.

The mechanism of actin incorporation and turnover in the nerve growth cone was examined by immunoelectron microscopy and low-light-level video microscopy of cultured neurons injected with biotin-labeled actin or fluorescently labeled actin. We first determined the sites of actin incorporation into the cytoskeleton of growth cones by immunoelectron microscopy of cultured neurons injected with biotin-labeled actin and reacted with an anti-biotin antibody and a gold-labeled secondary antibody. Shortly after the injection, biotin-actin molecules incorporated into the cytoskeleton were localized in the distal part of actin bundles in the filopodia and at the membrane-associated fringe of the actin filament network. With longer incubation, most actin polymers in the growth cones were labeled uniformly, suggesting that actin subunits are added preferentially at the membrane-associated ends of preexisting actin filaments. We then determined whether actin filaments translocate within the growth cones by low-light-level video microscopy of living neurons injected with fluorescently labeled actin and photobleached with a laser beam. When actin fluorescence at the leading edge of a growth cone was bleached, a rearward translocation of the bleached spot toward the base of the growth cone was observed. This observation suggests the presence of a rearward flow of actin polymers within growth cones. Taken together, these results indicate that there is a continuous addition of actin monomers at the leading edge of the growth cone and a successive rearward translocation of the assembled filaments.

Actins↗
PubMedDate not supplied

Automated morphometric endothelial analysis combined with video specular microscopy.

Contact and noncontact specular microscopes were tested in combination with a highly sensitive video residual-light camera and with the Kontron IPS (Image Processing System). The video information is recorded with a video recorder or with the IPS frame grabber, a digital image storage system. Examples of experimental and clinical applications are demonstrated. Nine linear and structural parameters are analyzed. Two endothelium-typical parameters are presented, which allow topological as well as hexagonal-specific geometric endothelial single-cell analysis.

Animals↗
PubMed2005

Low pH immobilizes and kills human leukocytes and prevents transmission of cell-associated HIV in a mouse model.

BACKGROUND: Both cell-associated and cell-free HIV virions are present in semen and cervical secretions of HIV-infected individuals. Thus, topical microbicides may need to inactivate both cell-associated and cell-free HIV to prevent sexual transmission of HIV/AIDS. To determine if the mild acidity of the healthy vagina and acid buffering microbicides would prevent transmission by HIV-infected leukocytes, we measured the effect of pH on leukocyte motility, viability and intracellular pH and tested the ability of an acidic buffering microbicide (BufferGel) to prevent the transmission of cell-associated HIV in a HuPBL-SCID mouse model. METHODS: Human lymphocyte, monocyte, and macrophage motilities were measured as a function of time and pH using various acidifying agents. Lymphocyte and macrophage motilities were measured using video microscopy. Monocyte motility was measured using video microscopy and chemotactic chambers. Peripheral blood mononuclear cell (PBMC) viability and intracellular pH were determined as a function of time and pH using fluorescent dyes. HuPBL-SCID mice were pretreated with BufferGel, saline, or a control gel and challenged with HIV-1-infected human PBMCs. RESULTS: Progressive motility was completely abolished in all cell types between pH 5.5 and 6.0. Concomitantly, at and below pH 5.5, the intracellular pH of PBMCs dropped precipitously to match the extracellular medium and did not recover. After acidification with hydrochloric acid to pH 4.5 for 60 min, although completely immotile, 58% of PBMCs excluded ethidium homodimer-1 (dead-cell dye). In contrast, when acidified to this pH with BufferGel, a microbicide designed to maintain vaginal acidity in the presence of semen, only 4% excluded dye at 10 min and none excluded dye after 30 min. BufferGel significantly reduced transmission of HIV-1 in HuPBL-SCID mice (1 of 12 infected) compared to saline (12 of 12 infected) and a control gel (5 of 7 infected). CONCLUSION: These results suggest that physiologic or microbicide-induced acid immobilization and killing of infected white blood cells may be effective in preventing sexual transmission of cell-associated HIV.

Acids↗