826
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Hudetz AG, Fehér G, Weigle CG, Knuese DE, Kampine JP. Video microscopy of cerebrocortical capillary flow: response to hypotension and intracranial hypertension. THE AMERICAN JOURNAL OF PHYSIOLOGY 1995; 268:H2202-10. [PMID: 7611470 DOI: 10.1152/ajpheart.1995.268.6.h2202] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Although autoregulation of cerebral blood flow is well established, the response of cerebral capillary circulation to reduced cerebral perfusion pressure (CPP) is unclear. The objective of this study was to determine whether red cell flow velocity in individual capillaries of the cerebral cortex is maintained during acute decreases in CPP. Microcirculation of the superficial parietal cerebral cortex of adult barbiturate-anesthetized artificially ventilated rats was visualized using a new design of closed-perfused cranial window and epifluorescent-intensified video microscopy. Fluorescein-isothiocyanate-labeled red blood cells (FRBC) injected intravenously were used as markers of capillary flow. CPP, defined as mean arterial pressure minus intracranial pressure, was reduced by controlled hemorrhage or by stepwise elevation of local intracranial pressure. The movement of FRBC in the parenchymal capillary network was video recorded at each pressure level, and FRBC velocity in each capillary was measured off-line with use of the dual-window digital cross-correlation technique. FRBC flux in the capillaries was measured by automated cell counting. FRBC velocity at normal perfusion pressure was 1.47 +/- 0.58 (SD) mm/s and changed little in the perfusion pressure range of 70-120 mmHg. The autoregulatory index in this pressure range was 0.0049 mm.s-1.mmHg-1. Opening of previously unperfused capillaries was not observed. FRBC flux correlated with FRBC velocity, but the latter was maintained in a narrower range than FRBC flux, suggesting a decrease in capillary diameter or hematocrit with decreasing perfusion pressure. The results suggest that flow autoregulation is associated with the maintenance of capillary flow velocity and that capillary recruitment does not contribute to flow autoregulation in the rat cerebral cortex.
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827
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Evans E, Ritchie K, Merkel R. Sensitive force technique to probe molecular adhesion and structural linkages at biological interfaces. Biophys J 1995; 68:2580-7. [PMID: 7647261 PMCID: PMC1282168 DOI: 10.1016/s0006-3495(95)80441-8] [Citation(s) in RCA: 342] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Adhesion and cytoskeletal structure are intimately related in biological cell function. Even with the vast amount of biological and biochemical data that exist, little is known at the molecular level about physical mechanisms involved in attachments between cells or about consequences of adhesion on the material structure. To expose physical actions at soft biological interfaces, we have combined an ultrasensitive transducer and reflection interference microscopy to image submicroscopic displacements of probe contact with a test surface under minuscule forces. The transducer is a cell-size membrane capsule pressurized by micropipette suction where displacement normal to the membrane under tension is proportional to the applied force. Pressure control of the tension tunes the sensitivity in operation over four orders of magnitude through a range of force from 0.01 pN up to the strength of covalent bonds (approximately 1000 pN)! As the surface probe, a microscopic bead is biochemically glued to the transducer with a densely-bound ligand that is indifferent to the test surface. Movements of the probe under applied force are resolved down to an accuracy of approximately 5 nm from the interference fringe pattern created by light reflected from the bead. With this arrangement, we show that local mechanical compliance of a cell surface can be measured at a displacement resolution set by structural fluctuations. When desired, a second ligand is bound sparsely to the probe for focal adhesion to specific receptors in the test surface. We demonstrate that monitoring fluctuations in probe position at low transducer stiffness enhances detection of molecular adhesion and activation of cytoskeletal structure. Subsequent loading of an attachment tests mechanical response of the receptor-substrate linkage throughout the force-driven process of detachment.
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828
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Takahashi E, Doi K. Visualization of oxygen level inside a single cardiac myocyte. THE AMERICAN JOURNAL OF PHYSIOLOGY 1995; 268:H2561-8. [PMID: 7611506 DOI: 10.1152/ajpheart.1995.268.6.h2561] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
The present paper describes theoretical and experimental bases for quantitation of the oxygen level inside a single isolated ventricular rat myocyte. We applied three-wavelength microspectrophotometry to a single cardiomyocyte, where the sensitivity of the spectrophotometry was augmented by a digital image processing technique known as video-enhanced microscopy. Oxygen-dependent changes in light absorption of the intracellular pigments were detected and represented with the use of a newly defined variable, Z, where one pixel of the reconstructed cell image corresponded to 0.2 microns. Theoretically, Z is a single-valued function of the fractional oxygen saturation of the intracellular pigment. We demonstrated in quiescent cardiomyocytes that Z changed according to extracellular PO2, where the relationship was sigmoidal with the extracellular PO2 for a half-maximal Z of 3.2 Torr. In the aerobic cell, conversion of cytochromes to the reduced forms by NaCN did not affect Z value. Therefore, we conclude that Z mainly represents the fractional oxygen saturation of myoglobin, thus reporting cytosolic PO2. We also demonstrated that for extracellular PO2 of 1.3 Torr, abolition of mitochondrial oxygen consumption by NaCN significantly elevated the intracellular oxygen level, suggesting existence of oxygen pressure gradients in a quiescent single cardiomyocyte that were proportional to oxygen flux.
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829
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Vlasov TD, Panteleev VG. [The programmed processing of the television image of microvessels]. FIZIOLOGICHESKII ZHURNAL IMENI I.M. SECHENOVA 1995; 81:148-50. [PMID: 8845873] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
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830
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Thorpe WP, Toner M, Ezzell RM, Tompkins RG, Yarmush ML. Dynamics of photoinduced cell plasma membrane injury. Biophys J 1995; 68:2198-206. [PMID: 7612864 PMCID: PMC1282125 DOI: 10.1016/s0006-3495(95)80402-9] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
We have developed a video microscopy system designed for real-time measurement of single cell damage during photolysis under well defined physicochemical and photophysical conditions. Melanoma cells cultured in vitro were treated with the photosensitizer (PS), tin chlorin e6 (SnCe6) or immunoconjugate (SnCe6 conjugated to a anti-ICAM monoclonal antibody), and illuminated with a 10 mW He/Ne laser at a 630 nm wavelength. Cell membrane integrity was assessed using the vital dye calcein-AM. In experiments in which the laser power density and PS concentration were varied, it was determined that the time lag before cell rupture was inversely proportional to the estimated singlet oxygen flux to the cell surface. Microscopic examination of the lytic event indicated that photo-induced lysis was caused by a point rupture of the plasma membrane. The on-line nature of this microscopy system offers an opportunity to monitor the dynamics of the cell damage process and to gain insights into the mechanism governing photolytic cell injury processes.
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831
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Wolenski JS, Cheney RE, Mooseker MS, Forscher P. In vitro motility of immunoadsorbed brain myosin-V using a Limulus acrosomal process and optical tweezer-based assay. J Cell Sci 1995; 108 ( Pt 4):1489-96. [PMID: 7615669 DOI: 10.1242/jcs.108.4.1489] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
To facilitate functional studies of novel myosins, we have developed a strategy for characterizing the mechanochemical properties of motors isolated by immunoadsorption directly from small amounts of crude tissue extracts. In this initial study, silica beads coated with an antibody that specifically recognizes the tail of myosin-V were used to immunoadsorb this motor protein from brain extracts. The myosin-containing beads were then positioned with optical tweezers onto actin filaments nucleated from Limulus sperm acrosomal processes and observed for motility using high resolution video DIC microscopy. The addition of brush border spectrin to the motility chamber enabled the growth of stable actin filament tracks that were approximately 4-fold longer than filaments grown in the absence of this actin crosslinking protein. The velocity of myosin-V immunoadsorbed from brain extracts was similar to that observed for purified myosin-V that was antibody-linked to beads or assessed using the sliding actin filament assay. Motile beads containing myosin-V immunoadsorbed from brain extracts bound poorly to nucleated actin filaments and were incapable of linear migrations following the addition of a different antibody that specifically recognizes the motor-containing head domain of myosin-V. Myosin-V motility was most robust in the absence of Ca2+. Interestingly, skeletal muscle tropomyosin and brush border spectrin had no detectable effect on myosin-V mechanochemistry. Myosin-V containing beads were also occasionally observed migrating directly on acrosomal processes in the absence of exogenously added actin.(ABSTRACT TRUNCATED AT 250 WORDS)
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832
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Rooryck V, Klinge B. Computer-assisted image processing for quantitative measurements of fractional bone area. A methodologic study. Acta Odontol Scand 1995; 53:115-22. [PMID: 7610775 DOI: 10.3109/00016359509005957] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
The purpose of this study was to evaluate a method for computer-assisted image processing to assess quantitatively fractional bone volume in sections of bone biopsies (part I). A second purpose was to apply this method in an experimental study to determine bone loss by measuring fractional bone area in sections of calvarial bone of gastrectomized rats and to compare this with a control group. Stained paraffin sections of skull bone of young rabbits (part I) and rats (part II) were examined. The histologic sections were placed on a microscope. A video camera was connected to the microscope, and the image transferred to a display monitor connected to a PC with dedicated software, performing the measurements. In the first part of the study tests of the reproducibility of the method were performed. The influence of factors such as external illumination and light intensity in the microscope was evaluated by measuring the same area several times at different times (= different illumination) and at different microscope light intensity levels. The automatic method was compared with a manual method, using a Merz grid but automatically calculated. The difference between the means of the manual and automatic measurements was determined with the paired t test. In the second part of the study the unpaired t test was used to determine the differences between the control group and experimental group, both for the manually and the automatically measured values.(ABSTRACT TRUNCATED AT 250 WORDS)
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833
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Fishell G, Blazeski R, Godement P, Rivas R, Wang LC, Mason CA. Optical microscopy. 3. Tracking fluorescently labeled neurons in developing brain. FASEB J 1995; 9:324-34. [PMID: 7896001 DOI: 10.1096/fasebj.9.5.7896001] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
For decades, time-lapse microscopy has been used to track dynamic events associated with biological phenomena. Time-lapse studies of the developing nervous system have been restricted to analysis of dissociated cell cultures or of a series of static images from living organisms. The advent of new fluorescent dyes and video imaging technology has produced novel views of the behavior of neurons in the context of the developing nervous tissue, such as migrations within and away from proliferative zones and navigation of axonal processes to synaptic targets. After fixation of the tissue preparation, time-lapse monitoring can be followed by other analytical techniques and forms of microscopy, e.g., immunocytochemistry or electron microscopy, producing information on the interactions of individual cells whose behavioral histories are known. The power of video time-lapse microscopy of living brain tissue lies in the firsthand documentation of developmental patterning, which in turn can serve as an experimental assay.
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834
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Puglisi RN, Doolin EJ, Hewitt CW. Morphometric analysis of rat renal allograft tolerance by computerized digital image processing. Transplant Proc 1995; 27:555-6. [PMID: 7879096] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
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835
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Bellary S, Arden WW, Schwartz RW, Anderson KW. Effect of lipopolysaccharide, leukocytes, and monoclonal anti-lipid A antibodies on erythrocyte membrane elastance. Shock 1995; 3:132-6. [PMID: 7749940] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
The micropipette aspiration technique was used to quantify membrane deformability of individual red blood cells (RBCs) before and after exposing whole blood and blood free of leukocytes to lipopolysaccharide (LPS). The ability of an anti-lipid A monoclonal antibody (E5) to inhibit the effects of LPS was also investigated. In the LPS/whole blood studies, a significant increase in elasticity modulus was observed following incubation with LPS. An increase in elasticity modulus indicates a decrease in RBC membrane deformability. The effect depended on the incubation time but was not concentration-dependent in the range studied (25, 40, or 170 micrograms/mL). When incubating blood free of leukocytes with LPS, the elasticity moduli of erythrocytes did not change. Results also showed that preincubation of the LPS with E5 prior to incubation with whole blood partially inhibited the effect of LPS, suggesting a possible mechanism of the beneficial actions of monoclonal antibodies in septic shock.
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836
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Gonçalves L, Cunha C. How to evaluate the quality in a system of video-microscopy in the field of anatomic pathology. ARCHIVES D'ANATOMIE ET DE CYTOLOGIE PATHOLOGIQUES 1995; 43:251-252. [PMID: 8526561] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
The acquisition of a video microscope image is explained by the concept of modulation transfer function to describe the quality of a microscope which should target a sensor of a video camera to allow around 50 pairs of lines per mm with a good contrast in the video-monitor. Taking this into consideration, high aperture lenses, a microscope with infinity optics, a low power video adapter and a high quality camera must be used.
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837
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838
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839
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840
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841
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Sanderson MJ, Dirksen ER. Quantification of ciliary beat frequency and metachrony by high-speed digital video. Methods Cell Biol 1995; 47:289-97. [PMID: 7476501 DOI: 10.1016/s0091-679x(08)60822-5] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
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842
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Mills JC, Wang S, Erecińska M, Pittman RN. Use of cultured neurons and neuronal cell lines to study morphological, biochemical, and molecular changes occurring in cell death. Methods Cell Biol 1995; 46:217-42. [PMID: 7609653 DOI: 10.1016/s0091-679x(08)61931-7] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
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843
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Lakhdar B, Potier M, L'Azou B, Cambar J. Image analyser as a tool for the study of in vitro glomerular vasoreactivity. Cell Biol Toxicol 1994; 10:291-5. [PMID: 7697487 DOI: 10.1007/bf00755772] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Many drugs used in clinics can dramatically reduce renal hemodynamics. For some years there have been developed in our laboratory two in vitro glomerular models, isolated glomeruli and mesangial cell cultures, to quantitate, by video image analyzer, the direct glomerular effect of vasoreactive agents. The present study shows the vasoconstrictive effects of angiotensin II and cyclosporin in both models and compares their glomerular vasoconstriction with or without vasodilating agents such as verapamil. This drug-induced glomerular vasoreactivity is time- and dose-dependent; moreover, it can be reversible after perfusion in control conditions. The interest of these in vitro glomerular models is validated by fair correlations between in vivo and in vitro data and between the responses of both. These models can be considered as tools for assessing glomerular vasoreactivity of nephrotoxic agents.
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844
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Lees D, Pugnère D, Castel A, Raux O, Travo P. A simple method for the quantitative evaluation of functional effects of xenobiotics with cultured cells. Cell Biol Toxicol 1994; 10:305-9. [PMID: 7697490 DOI: 10.1007/bf00755775] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
We present a simple, noninvasive, nondestructive all-purpose method for the quantitative evaluation of functional effects of xenobiotics with cultured cells and the work station for its routine, easy implementation. At present 1 to 150 cells growing in one to six dishes can be studied in parallel or otherwise at time intervals ranging from 10 s to 6 h or more, over periods of time ranging from a few tens of minutes to 3-4 days. Any aspect of cell physiological behavior can be studied (differentiation-dedifferentiation, migration, division, degeneration, death) without preliminary staining and/or fixation provided it results in optically visible changes.
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MESH Headings
- Animals
- Cells, Cultured/cytology
- Cells, Cultured/drug effects
- Cells, Cultured/metabolism
- Image Processing, Computer-Assisted/instrumentation
- Microscopy, Video/instrumentation
- Microscopy, Video/methods
- Muscle Contraction/drug effects
- Muscle, Smooth, Vascular/cytology
- Muscle, Smooth, Vascular/drug effects
- Rats
- Xenobiotics/pharmacology
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845
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Suzaki E, Kawai E, Kodama Y, Suzaki T, Masujima T. Quantitative analysis of superoxide anion generation in living cells by using chemiluminescence video microscopy. BIOCHIMICA ET BIOPHYSICA ACTA 1994; 1201:328-32. [PMID: 7947949 DOI: 10.1016/0304-4165(94)90058-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Superoxide anions (O2-) generated by rabbit neutrophils were detected and quantified by a video microscope equipped with a photon-counting camera. One count obtained by this system was equivalent to 59 amol of O2-. Maximum O2- production was observed at 6-8 min after stimulation and was estimated as 1.9 fmol/min per cell on the average.
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846
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Dodt HU, Zieglgänsberger W. Infrared videomicroscopy: a new look at neuronal structure and function. Trends Neurosci 1994; 17:453-8. [PMID: 7531885 DOI: 10.1016/0166-2236(94)90130-9] [Citation(s) in RCA: 99] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Brain slices were introduced as a standard preparation for neurophysiological experiments some 20 years ago. A drawback of this preparation compared with cell culture has been the difficulty to visualize individual neurones in standard thick slices. This problem has been overcome by the use of infrared videomicroscopy. Neurones in slices can now be visualized in great detail, and neuronal processes can be patch-clamped under direct visual control. Infrared video-microscopy has also been applied successfully to other fields of neuroscience such as neuronal development and neurotoxicity. A further development of infrared videomicroscopy enables one to visualize the spread of excitation in slices making the technique a tool for the direct investigation of neuronal function.
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847
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Itoh T, Yaegashi K, Kosaka T, Kinoshita T, Morimoto T. In vivo visualization of oxygen transport in microvascular network. THE AMERICAN JOURNAL OF PHYSIOLOGY 1994; 267:H2068-78. [PMID: 7977839 DOI: 10.1152/ajpheart.1994.267.5.h2068] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Oxygen transport from the blood to the tissues is a diffusive process driven by the gradient of oxygen tension (PO2). We developed an oxygen-quenching fluorescent membrane that allowed visualization of the PO2 distribution near the microvessels as optical patterns on the membrane by epifluorescence microscopy. This membrane was highly gas permeable to allow PO2 measurement and was transparent enough to also permit observation of the microcirculation. In combination with a newly devised gastight chamber and a micropositioning system, this membrane technique made it possible to visualize the PO2 distribution in the rat mesenteric microvascular network under well-defined conditions. Our preliminary findings indicate that the oxygen distribution in the microvascular network is heterogeneous and suggest that there is considerable release of oxygen from the arterioles. The time lag of the system for tracking rapid PO2 changes in vitro was shown to be negligible, indicating that dynamic PO2 changes occurring in vivo can also be assessed. This technique should provide a novel tool for the study of oxygen transport and metabolism under normal and abnormal conditions.
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MESH Headings
- Animals
- Intercalating Agents
- Membranes, Artificial
- Microcirculation/cytology
- Microcirculation/physiology
- Microscopy, Fluorescence/instrumentation
- Microscopy, Fluorescence/methods
- Microscopy, Video/instrumentation
- Microscopy, Video/methods
- Models, Cardiovascular
- Models, Theoretical
- Muscle, Smooth, Vascular/cytology
- Muscle, Smooth, Vascular/physiology
- Organometallic Compounds
- Oxygen/blood
- Partial Pressure
- Phenanthrolines
- Ruthenium
- Splanchnic Circulation
- Time Factors
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848
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Abstract
Combining patch-clamp and optical imaging techniques in brain slices offers several advantages for physiological studies of nerve cells. Numerous practical considerations weigh heavily in this design of an apparatus suitable for such combined measurements. These considerations include the thickness of the slices, the type of microscope to be used for imaging and the kind of optical signal to be measured. A system that combine optical and patch-clamp methods can be modified readily to permit studies of intracellular and extracellular signaling pathways via flash photolysis of caged compounds.
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849
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Silver RB, Reeves AP, Whitman M, Kelley B. Analysis of spatial and temporal patterns in the Ca2+ signal that signals nuclear envelope breakdown in sand dollar (Echinaracnius parma) cells. THE BIOLOGICAL BULLETIN 1994; 187:237-238. [PMID: 7811795 DOI: 10.1086/bblv187n2p237] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
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850
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Silver R. Video light microscopic imaging of the calcium signal that initiates nuclear envelope breakdown in sand dollar (Echinaracnius parma) cells. THE BIOLOGICAL BULLETIN 1994; 187:235-236. [PMID: 7811794 DOI: 10.1086/bblv187n2p235] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
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