Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Microscopy, Video”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 847 records · Page 47Linked to original sources
PubMed1993

Directional instability of kinetochore motility during chromosome congression and segregation in mitotic newt lung cells: a push-pull mechanism.

Most models of mitotic congression and segregation assume that only poleward pulling forces occur at kinetochores. However, there are reports for several different cell types that both mono-oriented and bi-oriented chromosomes oscillate toward and away from the pole throughout mitosis. We used new methods of high resolution video microscopy and computer-assisted tracking techniques to measure the positions over time of individual kinetochores with respect to their poles during mitosis in living newt lung cells. The results show that kinetochores oscillate throughout mitosis when they are tethered to spindle poles by attachment to the plus-ends of kinetochore microtubules (kMTs). Oscillations were not sinusoidal. Instead, kinetochores abruptly (as quick as 6 s or less) switched between persistent (approximately 1.5 min average duration) phases of poleward (P) and away from the pole (AP) movement. This kinetochore "directional instability" was a property of motility at the plus-ends of kMTs since fluorescent marks on the lattice of kMTs have previously been observed to exhibit only relatively slow P movement. Each P and AP phase consisted of one or a few constant velocity domains (approximately 1.7 microns/min average velocity). Velocities of P and AP phases were similar from prometaphase through mid-anaphase. Kinetochores occasionally switched to an indeterminant (N) phase of no or confused motion, which was usually brief compared to the durations of P and AP phases. Net chromosome displacements that occurred during congression to the equator or poleward movement during anaphase were primarily generated by differences in the durations and not the velocities of P and AP movements. Careful analysis of centromere deformation showed that kinetochore P movement produced pulling forces while kinetochore AP movement produced pushing forces. These data show that kinetochore directional instability is fundamental to the processes of chromosome congression and segregation. We argue that tension at the kinetochore attachment site is a key factor which controls the switching between P and AP phases of kinetochore motion.

Animals↗
PubMed1994

Reversal of rapidly transported protein and organelles at an axonal lesion.

The time required for both rapid axonally transported organelles (vesicles and tubulo-vesicular structures) and proteins to undergo anterograde to retrograde reversal at a crush site was examined using sciatic nerve preparations obtained from Xenopus laevis. The transport and reversal of a pulse of newly synthesized 35S-labeled proteins was studied with a position-sensitive detector of ionizing radiation. Organelle transport and reversal were studied using video microscopy. Both protein and organelle reversal were assessed in two bathing media: a physiological saline and a medium that was compatible with the intracellular environment (internal medium). The time required for protein transport to reverse at a ligature was determined as a function of the time interval between the application of the ligature and the arrival of the pulse at the ligature (lesion time). In physiological saline, reversal times were greatest, about 3.5 h, when the lesion time was 1 h or less and decreased to approximately 1.5 h for lesion times of 4-12 h. When corrected for the approximately 2 mm length of degeneration caused by the saline, the results were similar to those obtained in internal medium and indicated a minimal reversal time for proteins of about 2 h. Organelle transport was examined close to narrow lesions in single myelinated axons. That the organelles moving away from the lesion represented organelles that had undergone reversed transport was suggested by observation of the reversal of individual organelles, and by a correlation between the flux of organelles towards and away from the lesion. Analysis of organelle flux within and adjacent to a segment of axon isolated by two lesions indicated that 70-80% of organelles moving away from a lesion represented reversed transport. Observations in internal medium were consistent with a reversal time of < 15 min, and in physiological saline < 30 min. The substantially smaller reversal time for organelle transport as compared to protein transport is consistent either with the existence of two types of organelles with different reversal times and hence different reversal mechanisms, or with the possibility that during reversal proteins are off-loaded from carrier organelles and subsequently up-loaded to different organelles.

Animals↗
PubMed1998

Glutathione protects metastatic melanoma cells against oxidative stress in the murine hepatic microvasculature.

Calcein-labeled B16 melanoma (B16M) cells were injected intraportally, and in vivo video microscopy was used to study the distribution and damage of cancer cells arrested in the liver microvasculature over a period of 4 hours. The contribution of glutathione (GSH)-dependent antioxidant machinery to the possible oxidative stress-resistance mechanism of B16M cell was determined by in vitro incubation with the selective inhibitor of GSH synthesis L-buthionine (S,R)-sulphoximine (BSO) before B16M cell injection in untreated and 0.5-mg/kg lipopolysaccharide (LPS)-treated mice. In addition, untreated and LPS-treated isolated syngeneic hepatic sinusoidal endothelial cells (HSE) were used to determine in vitro their specific contribution to B16M cell damage. Trauma inherent to intrasinusoidal lodgement damaged 35% of B16M cells in both normal and LPS-treated mouse liver. The rest of the arrested B16M cells remained intact in normal liver for at least 4 hours, although their damaged cell percentage significantly (P < .05) increased since the second hour in normal mice injected with BSO-treated cells and since the first hour in LPS-treated mice given untreated cells. Recombinant human interleukin-1 receptor antagonist (rHuIL-1-Ra) given to mice 15 minutes before LPS significantly (P < .05) abrogated B16M cell damage. On the other hand, 40% of the B16M cells co-cultured with unstimulated HSE and 70% of the co-cultured with LPS-treated HSE became sensitive to endothelial cell-mediated damage after BSO treatment. These results demonstrate that a high intracellular level of GSH protects B16M cells from possible in vivo and in vitro sinusoidal cell-mediated oxidative stress, contributing to the mechanism of metastatic cell survival within the hepatic microvasculature.

Animals↗
PubMed1996

Quantitative analysis of the spreading of the mouse trophoblast in vitro: a model for early invasion.

The outgrowth of the mouse blastocyst in culture represents an in vitro model of trophoblastic invasion. In the present study we analysed trophoblast spreading by time lapse video microscopy. Trophoblast spreading consists of (1) the migration and (2) the giant cell transformation of trophoblast cells, (3) the proliferation of ectoplacental cone (EPC) cells and (4) the subsequent transformation of EPC cells into the secondary giant cells. During migration, ruffling of the trophoblast cell membrane is followed by the formation of lamellipodia. The mean surface areas of the spreading trophoblast, measured in more than 100 cultured blastocysts, increased linearly from 48 to 96 h of culture, while the linear migratory speed at the periphery of the outgrowth declined as the time of culture advanced. The EPC cells increased in size approximately eightfold during the giant cell transformation. The apparent nuclear:cytoplasmic ratios, i.e., ratios between the size of nucleus and that of the cytoplasm, measured as the surface areas on the photomicrographs, of EPC cells increased between 40-46 h of culture, but a sharp decline in the ratio occurred between 50 and 51 h of culture, reflecting either the sudden and tremendous increase in the cellular volume and/or spreading of the cytoplasm. The rates of trophoblast spreading varied considerably among the blastocysts of different genetic constitution examined (ICR, C57BL/6, C3H/He and (B6 x C3)F1. It was fastest in blastocysts obtained from matings of males and females of (B6 x C3)F1, and slowest in the C57BL/6 embryos. The differences in the rate of outgrowth observed may not simply be ascribed to difference in the developmental speed of the early embryos, because the rate of outgrowth reached a plateau at about 96-120 h and no "catch-up' was observed by leaving the blastocysts in culture longer. Our results strongly suggest the possible presence of genetic regulatory mechanisms underlying trophoblast outgrowth; further analysis of the phenomenon may provide clues to understand the molecular mechanisms of trophoblastic invasion during the early phase of implantation, hopefully leading to improved success rates of in vitro fertilization-embryo transfer.

Animals↗
PubMed1996

Postnatal addition of satellite cells to parasympathetic neurons.

We have examined the postnatal development of satellite cells associated with parasympathetic neurons of mouse salivary duct ganglia. The number of satellite cells associated with each neuron was found to increase during the first 8 weeks after birth but remained constant thereafter. This corresponds to the period of maximal growth of the salivary gland that serves as the target organ innervated by these neurons. At all ages examined, the number of satellite cells associated with each neuron was found to be highly correlated with neuronal volume. The development of satellite cells associated with individual identified neurons was followed directly by in vivo video microscopy over several months, and the number of satellite cell nuclei was found to increase in regions of the neuronal surface with increasing numbers of synaptic boutons. These results indicate that the postnatal addition of satellite cells to parasympathetic neurons is linked to neuronal enlargement and that synaptic remodeling occurs in concert with satellite cell development.

Animals↗
PubMed1996

Locomotion of neutrophil fragments occurs by graded radial extension.

The only kinematic description of cell locomotion that relates the dynamics of actin filaments to whole cell movement is the graded radial extension (GRE) model for fish keratocytes, which glide without changing their shapes or sizes. To test whether the GRE model is applicable to other cell types, we analyzed the detailed shape changes during locomotion of heat-induced motile fragments of human polymorphonuclear leukocytes (PMNs). These fragments, called cytokineplasts, were loaded uniformly with a fluorescent cytoplasm-staining dye and their motility and shape changes were analyzed by fluorescence-video microscopy and digital image processing. Two-dimensional (2-D) analysis showed that cytokineplasts only changed their shapes and sizes slightly and apparently maintained their roughly circular shapes, whereas fluorescence-intensity analysis revealed distinct changes in their cytoplasmic thickness profiles. Furthermore, small structures on the cytoplasmic margins behaved as predicted by the GRE model, which therefore is probably also applicable to the parental PMNs, which show complex shape changes. This is the first indication that the GRE model operates in non-fish-keratocyte cells and may, therefore, be a universal model of cell locomotion.

Cell Movement↗
PubMed1997

Mitochondrial inheritance: cell cycle and actin cable dependence of polarized mitochondrial movements in Saccharomyces cerevisiae.

Asymmetric growth and division of budding yeast requires the vectorial transport of growth components and organelles from mother to daughter cells. Time lapse video microscopy and vital staining were used to study motility events which result in partitioning of mitochondria in dividing yeast. We identified four different stages in the mitochondrial inheritance cycle: (1) mitochondria align along the mother-bud axis prior to bud emergence in G1 phase, following polarization of the actin cytoskeleton; (2) during S phase, mitochondria undergo linear, continuous and polarized transfer from mother to bud; (3) during S and G2 phases, inherited mitochondria accumulate in the bud tip. This event occurs concomitant with accumulation of actin patches in this region; and (4) finally, during M phase prior to cytokinesis, mitochondria are released from the bud tip and redistribute throughout the bud. Previous studies showed that yeast mitochondria colocalize with actin cables and that isolated mitochondria contain actin binding and motor activities on their surface. We find that selective destabilization of actin cables in a strain lacking the tropomyosin 1 gene (TPM1) has no significant effect on the velocity of mitochondrial motor activity in vivo or in vitro. However, tpm1 delta mutants display abnormal mitochondrial distribution and morphology; loss of long distance, directional mitochondrial movement; and delayed transfer of mitochondria from the mother cell to the bud. Thus, cell cycle-linked mitochondrial motility patterns which lead to inheritance are strictly dependent on organized and properly oriented actin cables.

Actins↗
PubMed1999

Locomotory waves of Koruga and Deltotrichonympha: flagella wag the cell.

We investigated the nature of the locomotory waves of Koruga and Deltotrichonympha, flagellates living symbiotically in the hindgut of the Australian termite Mastotermes darwiniensis. The locomotory waves consist of two components: metachronal waves of flagellar beating and undulations of the cell surface, which propagate synchronously with the same wavelength, frequency, and velocity. We asked, do body waves cause flagellar waves, or vice versa? Using video microscopy and selective inhibitors and drugs, we found that (1) the amplitude of flagellar waves remains constant independent of variations in the amplitude of body waves, (2) flagellar waves can occur in the complete absence of body waves, (3) flagellar waves can induce body waves on swollen regions, (4) inhibition of flagellar beating by dynein inhibitors causes disappearance of body waves, and (5) cytochalasin D induces changes in cell shape but does not inhibit locomotory waves. Therefore, flagellar waves are not produced passively by an active contractile system in the cell cortex; instead, metachronally beating flagella exert waves of pressure that induce passive undulations of a pliant cell surface. These results support Machemer's [1974] theoretical analysis of the data of Cleveland and Cleveland [1966: Arch. Protistenk. 109:39-63], who believed the opposite.

Animals↗
PubMed1999

Relationship between cell migration and cell cycle during the initiation of epithelial to fibroblastoid transition.

The NBT-II rat bladder carcinoma cell line, which displays epithelial to mesenchymal transition or EMT in response to FGF-1 stimulation, was used to study the interrelationships between cell cycle and cell scattering and locomotion. Time-lapse video microscopy experiments were performed with asynchronous growing cells and lovastatin-arrested cells. FGF-1 stimulation induced cell movement in cells in all phases of the cell cycle, except G2 + M phase, in which cells did not respond to stimulation. The delay between cell stimulation and cell movement depended on the age of the cell at the beginning of cell stimulation: cells less than 4 h old when stimulated by FGF-1 had a 1-h delay whereas cells more than 4 h old had a 3-h delay. Cells stimulated before they were 4 h old were temporarily arrested in their cell cycle progression. Older cells underwent mitosis on schedule. Lovastatin-treated cells were shown to be synchronized in the G1 phase and to migrate simultaneously after FGF-1 stimulation. These results indicate that the G1 phase was a critical phase for FGF-1 induced cell migration during epithelial to fibroblastoid transition.

Animals↗
PubMed2000

Characterization of a microtubule assembly inhibitor from Xenopus oocytes.

The dynamic properties of microtubules (MTs) are important for a wide variety of cellular processes, including cell division and morphogenesis. MT assembly and disassembly in vivo are regulated by cellular factors that influence specific parameters of MT dynamics. Here, we describe the characterization of a previously reported MT assembly inhibitor activity from Xenopus oocytes [Gard and Kirschner, 1987: J. Cell Biol. 105:2191-2201]. Video microscopy measurements reveal that the inhibitor specifically decreases the plus end growth rate of MTs and increases the critical concentration for tubulin. However, catastrophe frequency, rescue frequency, and shrinkage rates are not affected by the activity. Chromatography on Mono Q and hydroxyapatite columns has shown that the activity cofractionates with a subpopulation of tubulin. This tubulin subpopulation and the MT assembly inhibitor activity also co-migrate with a large S value (25-30S) on sucrose gradients. The high molecular weight tubulin complex and the MT assembly inhibitor activity are both developmentally regulated and disappear after oocyte maturation with progesterone.

Animals↗
PubMed2000

Role of lysophosphatidic acid and rho in glioma cell motility.

We have studied the effects of the bioactive phospholipid lysophosphatidic acid (LPA) on cell lines derived from highly invasive human glioblastoma multiforme (GBM). Using transwell migration assays, we show that LPA stimulates both chemokinetic and chemotactic migration of glioma cells. Blood brain barrier breakdown and leakage of serum components that most likely include LPA are common features of GBM. Therefore, the effects of LPA on glioma cell motility are intriguing given the fact that, in vivo, GBM cells often migrate great distances from the main tumor, rendering successful therapy extremely difficult. We show here that LPA initiates a variety of signaling cascades in glioma cells. LPA-enhanced transwell migration was sensitive to pertussis toxin (PTX) treatment suggesting an important role for G(i) subtype of G proteins. LPA also stimulated Ca(2+) fluctuations and activation of extracellular signal-regulated kinases (ERKS) 1 and 2, although blocking either pathway had little effect on glioma cell migration. Exposure of glioma cells to LPA resulted in phosphorylation of the regulatory light chain (RLC) of myosin II and the formation of stress fibers and focal adhesions. These effects were blocked by Y-27632, an inhibitor of Rho-activated ROCK kinases. Time-lapse video microscopy revealed that Y-27632-treatment caused cells to assume long thin morphologies that suggested deficiencies in the contractile apparatus. Furthermore, many cells exhibited a conspicuous extension of processes when Rho/ROCK kinase cascades were inhibited. The above results suggest that LPA/Rho signaling cascades play important roles in glioma cell motility and that exposure of tumor cells to LPA in vivo may contribute to their invasive phenotype.

Cell Movement↗
PubMed1996

Mutagenesis of ser41 to ala inhibits the association of GAP-43 with the membrane skeleton of GAP-43-deficient PC12B cells: effects on cell adhesion and the composition of neurite cytoskeleton and membrane.

To investigate the molecular basis for GAP-43 function in axon outgrowth, we produced a mutant, GAP-43 (Ala41), whose interaction with calmodulin in vitro was unaffected by increasing Ca2+ concentrations, and stably transfected it into GAP-43-deficient PC12B cells. Several lines that expressed wild-type or mutant protein at levels that resembled endogenous GAP-43 expression in PC12 controls were subcloned and characterized. GAP-43 (Ala41) was significantly more extractable with Nonidet P-40 and less tightly associated with the membrane skeleton than the wild-type protein. Furthermore, GAP-43 (Ala41) expression by PC12B cells profoundly affected their phenotype: First, observation of living cells using video-enhanced microscopy revealed irregular plasma membranes with numerous blebs and protrusions and neurites that appeared thin and varicose. Second, both the cells' ability to remain attached to laminin substrates and the amount of alpha 1 beta 1 integrin expressed on the cell surface was significantly decreased. Finally, peripherin transport, which is abnormal in PC12B cells, could be rescued by transfection of wild-type GAP-43 but not the GAP-43 (Ala41) mutant. The phenotypic abnormalities resemble other cell types in which membrane skeleton/plasma membrane interactions have been functionally decoupled, and our results are consistent with the notion that these interactions may be abnormal in GAP-43 (Ala41)-expressing PC12B cells, either as a direct consequence of the mutation or arising secondarily to the altered availability of calmodulin in the growing neurite.

Alanine↗
PubMed1999

Extracellular potassium rapidly inhibits axonal transport of particles in cultured mouse dorsal root ganglion neurites.

Changes in extracellular potassium concentration ([K+]o) modulate a variety of neuronal functions. However, whether axonal transport, which conveys materials to the appropriate destination for morphogenesis and other neuronal functions, depends on the extracellular K+ environment remains unclear. We therefore examined the effects of changes in [K+]o on axonal transport of particles visualized by video-enhanced microscopy in cultured mouse dorsal root gan-glion neurites. Increases in [K+]o (delta[K+]o > or = 2.5 mM) from control concentration (5 mM) inhibited both anterograde and retrograde axonal transport within a few minutes in a concentration-dependent manner. Conversely, removal of extracellular K+ induced the rapid facilitation of transport in both directions. These inhibitory and facilitatory responses were completely blocked by the K+ channel blocker tetraethylammonium (TEA), suggesting that the effect of changes in [K+]o involves the TEA-sensitive K+ channels. Increases in [K+]o provoked membrane depolarization in the absence and presence of TEA. Another depolarizing agent, veratridine, did not produce an effect on axonal transport. These results suggest that the extracellular K+-mediated inhibition of axonal transport does not depend on membrane depolarization. The inhibitory effect of increasing [K+]o on axonal transport was retained in calcium (Ca2+)-free extracellular medium, indicating that the inhibitory effect of extracellular K+ does not result from Ca2+ influx through voltage-dependent Ca2+ channels. In chloride (CI-)-free medium, increasing [K+]o failed to inhibit axonal transport, implying that the extracellular K+-mediated inhibition of axonal transport may be due to an increase in intracellular Cl- concentration associated with increases in the net inward movement of K+ and CI- across the membrane. Our results suggest that the extracellular K+ environment is involved in the rapid modulation of axonal transport of particles in dorsal root ganglion neurites.

Animals↗
PubMed1996

Phagocytozing ameboid microglial cells studied in a mouse corpus callosum slice preparation.

Highly motile brain macrophages/microglial cells were observed in the cingulum and supraventricular corpus callosum, an area termed by del Rio-Hortega the "fountain of microglia." This is the first study that uses time lapse video microscopy in acute cortical brain slices to analyze directly the motile and phagocytic behaviour of these cells. The cells migrated within minutes to the slice surface and actively screened their surrounding with velum-like processes. Dead/damaged cells on the slice surface were contacted by the processes and phagozytozed within minutes. A method to add red blood cells in a defined density was used to observe the phagocytosis.

Animals↗
PubMed1999

Receptor-mediated transport of foreign DNA into preimplantation mammalian embryos.

Mouse and rabbit preimplantation embryos with intact zona pellucida were incubated for 3 hr with DNA-carrying constructs containing insulin as an internalizable ligand: (insulin-polylysine)-DNA and (insulin-polylysine)-DNA-(streptavidin-polylysine)-(biotinylated adenovirus). Video-intensified microscopy demonstrated that the constructs penetrated the zona pellucida and accumulated in the blastomere perinuclear space. The percentage of blastocysts formed was about 70% after incubation of zygotes and two-cell embryos with the constructs. Foreign DNA was detected after 51 hr in 80% of rabbit embryos and after 96 hr in 73% of mouse embryos. Inclusion of various adenoviruses into the construct improved foreign DNA preservation in early embryos. Blot hybridization revealed genome-integrated foreign DNA in 12- and 15-day mouse embryos and in a newborn. Thus, the ligand-mediated mechanism can be employed for introducing foreign genetic material into early mammalian embryos; insulin provides for delivery inside the cell and to the nucleus, while adenoviruses ensure release from endosomes.

Adenoviridae↗
PubMed2000

Effects of alpha1-adrenoceptor antagonists on cultured prostatic smooth muscle cells.

BACKGROUND: alpha1-adrenoceptor (alpha1-AR) antagonists, used to relieve the lower tract urinary symptoms (LUTS) in benign prostate hyperplasia (BPH) patients, are thought to act in inhibiting the contraction of stromal smooth muscle. An attempt was made using new technology to visualize and quantify the effect of alpha1-AR antagonists in a cell culture model of prostatic smooth muscle cells (SMC). METHODS: Prostatic smooth muscle cells cultured from human prostate tissue were treated with alpha1-AR agonists and antagonists. The effects on cell growth, cell contraction, differentiation status, and apoptosis were determined by means of an MTT cell viability assay, time-lapse video microscopy, RT-PCR analysis, and FACS analysis of annexin V/propidium iodide-stained cells, respectively. RESULTS: Prostatic smooth muscle cells derived from prostate tissue expressed SMC-specific markers. They showed spontaneous contractions, and phenylephrine increased the percentage of contracting cells by 3-fold. alpha1-AR antagonists inhibited spontaneous as well as phenylephrine-induced contractions. Long-term treatment with doxazosin induced differentiation tended towards a contractile phenotype, as indicated by an increase of the ratio of smooth muscle heavy chain myosin subtypes SM2/SM1. There was, however, no effect on cell growth. High concentrations of antagonist (100 microM) induced apoptosis in about 80% of the treated SMC. This effect was not cell-type-specific and was also seen in skin fibroblasts and immortalized prostate epithelial cells. CONCLUSION: In an easy-to-handle cell culture model of prostatic smooth muscle cells, the effects of alpha1-AR antagonists on cell contraction, growth, and differentiation can be investigated. The results indicate that in addition to inhibition of cell contraction, alpha1-AR antagonists have the potential to induce apoptosis.

Adrenergic alpha-1 Receptor Antagonists↗
PubMed2001

Extremely low frequency electromagnetic fields and heat shock can increase microvesicle motility in astrocytes.

The effect of extremely low frequency electromagnetic fields (EMF) on microvesicles was examined in rat astrocytes by video-enhanced microscopy in combination with a perfusable cell chamber. The EMF effect was compared with the effect of heat shock (HS) and with a combination of them both. The velocity of microvesicles was measured using image processing software (NIH Scion image 1.61). After exposure of astrocytes to EMF (50 Hz, 100microT, 1 h), the velocity of microvesicles in astrocytes increased from 0.32 +/- 0.03 microm/s (n = 120, 95% CI) in the untreated control group to 0.41 +/- 0.03 microm/s (n = 175, 95% CI). Fifteen minutes after HS (45 degrees C, 10 min) the microvesicles showed a velocity of 0.56 +/- 0.03 microm/s (n = 125, 95% CI). Combination of HS and EMF led to an increase in velocity up to 0.54 +/- 0.03 microm/s (n = 110, 95% CI). No significant difference between HS and HS+EMF was found. Compared to the untreated control group, the increased microvesicle velocity of the exposed cells might be a stress response of the cell. It is possibly a sign of intensified intracellular traffic required to adjust the metabolic needs.

Animals↗
PubMed2002

Poly(vinyl alcohol)-coated microfluidic devices for high-performance microchip electrophoresis.

The channels of microfluidic glass chips have been coated with poly(vinyl alcohol) (PVA). Applied for microchip electrophoresis, the coated devices exhibited a suppressed electroosmotic flow and improved separation performance. The superior performance of PVA-coated channels could be demonstrated by electrophoretic separations of labeled amines and by video microscopy. While a distorted sample zone is injected using uncoated channels the application of PVA-coated channels results in an improved shape of the sample zone with less band broadening. Applying PVA-coated microchips for the separation of amines labeled with Alexa Fluor 350 even sub-second separations, utilizing a separation length of only 650 microm, could be obtained, while this was not possible using uncoated devices. By using PVA-coated devices rather than an uncoated chip a threefold increase in separation efficiencies could be observed. As the electroosmotic flow (EOF) was suppressed, the anionic compounds were detected at the anode whereas the dominant EOF in uncoated devices resulted in an effective mobility to the cathode. Besides improved separation performance another important feature of the PVA-coated channels was the suppressed adsorption of fluorescent compounds in repetitive runs which results in an improved robustness and detection sensitivity. Applying PVA-coated channels, rinsing or etching steps could be omitted while this was necessary for a reliable operation of uncoated devices.

Amines↗