Determination of macromolecular exchange and PO2 in the microcirculation: a simple system for in vivo fluorescence and phosphorescence videomicroscopy

Torres, Luciana Neves; Filho, Ivo P. Torres

doi:10.1590/s0100-879x2001000100017

Cited by 5 publications

(4 citation statements)

References 21 publications

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“…Indirect oxygen sensors in bacteria such as the activity of luciferase and the fluorescence of GFP, which are both dependent on the molecular oxygen, can demonstrate the presence of oxygen at specific body sites (Marteyn et al ., 2010), but do not indicate the exact concentration of available oxygen. Alternatively, a new generation of oxygen sensors based on the phosphorescence of Pd‐porphyrin has been successfully used to examine oxygen perfusion in the microcirculation (Torres and Torres Filho, 2001) and hepatic tumours (Handa et al ., 2010). Additionally, pimonidazole (PIMO) can be administered orally or systemically, and used as a marker for hypoxia in histopathological sections.…”

Section: Future Directionsmentioning

confidence: 99%

Breathing life into pathogens: the influence of oxygen on bacterial virulence and host responses in the gastrointestinal tract

Marteyn¹,

Scorza²,

Sansonetti³

et al. 2010

Cellular Microbiology

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SummaryThe gastrointestinal tract provides a variety of environmental challenges to any bacterium seeking to successfully colonize or cause disease in a host. A major obstacle is the varied oxygen concentrations encountered at different sites in the intestine. Here we review the mechanisms bacterial pathogens utilize to sense oxygen within the gastrointestinal tract, and recent insights into how this acts as a signal to trigger virulence and to modulate host responses.

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Section: Future Directionsmentioning

confidence: 99%

Breathing life into pathogens: the influence of oxygen on bacterial virulence and host responses in the gastrointestinal tract

Marteyn¹,

Scorza²,

Sansonetti³

et al. 2010

Cellular Microbiology

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“…The rats had acute cannulas implanted into the femoral (or carotid) artery and the jugular vein to measure blood pressure and to collect blood samples. The rat mesentery was prepared for microvascular studies, as previously described (40,43). Briefly, an ileal loop and the associated mesentery were carefully exteriorized and placed on top of a temperature-controlled Plexiglas viewing platform (18), without excessive stretch.…”

Section: Raman Intravital Microscopementioning

confidence: 99%

Measurement of hemoglobin oxygen saturation using Raman microspectroscopy and 532-nm excitation

Filho¹,

Terner²,

Pittman³

et al. 2008

Journal of Applied Physiology

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The resonant Raman enhancement of hemoglobin (Hb) in the Q band region allows simultaneous identification of oxy- and deoxy-Hb. The heme vibrational bands are well known at 532 nm, but the technique has never been used to determine microvascular Hb oxygen saturation (So(2)) in vivo. We implemented a system for in vivo noninvasive measurements of So(2). A laser light was focused onto areas of 15-30 microm in diameter. Using a microscope coupled to a spectrometer and a cooled detector, Raman spectra were obtained in backscattering geometry. Calibration was performed in vitro using blood at several Hb concentrations, equilibrated at various oxygen tensions. So(2) was estimated by measuring the intensity of Raman signals (peaks) in the 1,355- to 1,380-cm(-1) range (oxidation state marker band nu(4)), as well as from the nu(19) and nu(10) bands (1,500- to 1,650-cm(-1) range). In vivo observations were made in microvessels of anesthetized rats. Glass capillary path length and Hb concentration did not affect So(2) estimations from Raman spectra. The Hb Raman peaks observed in blood were consistent with earlier Raman studies using Hb solutions and isolated cells. The correlation between Raman-based So(2) estimations and So(2) measured by CO-oximetry was highly significant for nu(4), nu(10), and nu(19) bands. The method allowed So(2) determinations in all microvessel types, while diameter and erythrocyte velocity could be measured in the same vessels. Raman microspectroscopy has advantages over other techniques by providing noninvasive and reliable in vivo So(2) determinations in thin tissues, as well as in solid organs and tissues in which transillumination is not possible.

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“…The rats had acute cannulas implanted into the femoral (or carotid) artery and the jugular vein to measure blood pressure and to collect blood samples. The rat mesentery was prepared for microvascular studies as previously described (42,43,45). Briefly, via a midline laparotomy, an ileal loop and the associated mesentery were carefully exteriorized.…”

Section: Calibrationmentioning

confidence: 99%

Hemoglobin oxygen saturation measurements using resonance Raman intravital microscopy

Filho

Terner

Pittman

et al. 2005

American Journal of Physiology-Heart and Circulatory Physiology

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A system is described for in vivo noninvasive measurements of hemoglobin oxygen saturation (HbO2Sat) at the microscopic level. The spectroscopic basis for the application is resonant Raman enhancement of Hb in the violet/ultraviolet region, allowing simultaneous identification of oxy- and deoxyhemoglobin with the same excitation wavelength. The heme vibrational bands are well known, but the technique has never been used to determine microvascular HbO2Sat in vivo. A diode laser light (power: 0.3 mW) was focused onto sample areas 15–30 μm in diameter. Raman spectra were obtained in backscattering geometry by using a microscope coupled to a spectrometer and a cooled detector. Calibration was performed in vitro by using glass capillaries containing blood at several Hb concentrations, equilibrated at various oxygen tensions. HbO2Sat was estimated using the Raman band intensities at 1,360 and 1,375 cm−1. Glass capillary path length and Hb concentration had no effect on HbO2Sat estimated from Raman spectra. In vivo observations were made in blood flowing in microvessels of the rat mesentery. The Hb Raman peaks observed in oxygenated and deoxygenated blood were consistent with earlier Raman studies that used Hb solutions and isolated cells. The method allowed HbO2Sat determinations in the whole range of arterioles, venules, and capillaries. Tissue transillumination allowed diameter and erythrocyte velocity measurements in the same vessels. Raman microspectroscopy offers distinct advantages over other currently used techniques by providing noninvasive and reliable in vivo determinations of HbO2Sat in thin tissues as well as in solid organs and tissues, which are unsuitable for techniques requiring transillumination.

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Determination of macromolecular exchange and PO2 in the microcirculation: a simple system for in vivo fluorescence and phosphorescence videomicroscopy

Cited by 5 publications

References 21 publications

Breathing life into pathogens: the influence of oxygen on bacterial virulence and host responses in the gastrointestinal tract

Breathing life into pathogens: the influence of oxygen on bacterial virulence and host responses in the gastrointestinal tract

Measurement of hemoglobin oxygen saturation using Raman microspectroscopy and 532-nm excitation

Hemoglobin oxygen saturation measurements using resonance Raman intravital microscopy

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