Search results for "Intravital microscopy"
showing 7 items of 57 documents
Pro-inflammatory T helper 17 directly harms oligodendrocytes in neuroinflammation.
2021
Significance Multiple sclerosis (MS) is a neuroinflammatory, demyelinating disease that represents one of the most frequent causes of irreversible disability in young adults. Treatment options to halt disability are limited. We discovered that T helper (Th)17 cells in contact with oligodendrocytes produce higher levels of glutamate and induce significantly greater oligodendrocyte damage than their Th2 counterpart. Blockade of CD29, which is linked to glutamate release pathways and expressed in high levels on Th17 cells, preserved human oligodendrocyte processes from Th17-mediated injury. Our data thus provide evidence for the direct and deleterious attack of Th17 cells on the myelin compart…
Hydrodynamic liver gene transfer mechanism involves transient sinusoidal blood stasis and massive hepatocyte endocytic vesicles
2005
The present study contributes to clarify the mechanism underlying the high efficacy of hepatocyte gene transfer mediated by hydrodynamic injection. Gene transfer experiments were performed employing the hAAT gene, and the efficacy and differential identification in mouse plasma of human transgene versus mouse gene was assessed by ELISA and proteomic procedures, respectively. By applying different experimental strategies such as cumulative dose-response efficacy, hemodynamic changes reflected by venous pressures, intravital microscopy, and morphological changes established by transmission electron microscopy, we found that: (a) cumulative multiple doses of transgene by hydrodynamic injection…
Reactive oxygen species mediate angiotensin II-induced leukocyte-endothelial cell interactions in vivo
2001
Abstract Chronically elevated angiotensin II (Ang-II)-induced hypertension is partly mediated by superoxide production. In this study, we have investigated whether the leukocyte-endothelial cell interactions elicited by Ang-II involve reactive oxygen species (ROS) generation. Intravital microscopy within the rat mesenteric microvessels was used. Superfusion (60 min) with Ang-II (1 nM) induced significant increases in leukocyte rolling flux, adhesion, and emigration, which were inhibited by pretreatment with superoxide dismutase or catalase. Dihydrorhodamine-123 oxidation indicated that ROS are primarily produced by the vessel wall. Administration of dimethylthiourea, desferrioxamine, or N-a…
Intravital fluorescence microscopy for the study of leukocyte interaction with platelets and endothelial cells
1999
Publisher Summary This chapter introduces the techniques of intravital microscopy as a tool to study the microcirculation in intact animals under conditions of oxidative stress. Intravital fluorescence microscopy can be performed with almost all types of epiillumination microscopes available. The introduction of fluorescent dyes and refined epiillumination techniques has significantly advanced the possibilities of intravital microscopic studies of the liver microcirculation, including quantitative analyses of both circulatory parameters and cellular mechanisms. Using appropriate dyes, intravital microscopy allows the study of (1) microvascular perfusion, (2) leukocyte-endothelial cell inter…
EndothelinA receptor antagonist BSF-208075 causes immune modulation and neuroprotection after stroke in gerbils.
2005
Leukocytes contribute to the ischemia-reperfusion injury. Recent studies suggested endothelins could be important mediators for leukocyte activation in stroke. We tested if the endothelinA receptor antagonist BSF-208075 (ambrisentan) could reduce an ischemic lesion by modulation of leukocyte-endothelium interactions. Twenty-four gerbils underwent either a sham operation (n=6) or 15 min of bilateral carotid artery occlusion resulting in global cerebral ischemia. Ischemic animals received normal saline (n=6), 5 mg/kg BSF-208075 (n=6) or 30 mg/kg (n=6) administered intravenously at 10 min of reperfusion. Leukocytes rolling or adhering to endothelium were counted by intravital microscopy in par…
Pentobarbital-sensitive EDHF comediates ACh-induced arteriolar dilation in the hamster microcirculation
1999
It is unclear to what extent the endothelium-derived hyperpolarizing factor (EDHF) contributes to the control of microcirculatory blood flow in vivo. We analyzed, by intravital microscopy in hamster muscles, the potential role of EDHF along the vascular tree under stimulated (ACh) or basal conditions. Experiments were performed in conscious as well as anesthetized (pentobarbital, urethan) animals. Additionally, cellular effects of the potential EDHF were studied in isolated small arteries. In pentobarbital-anesthetized animals, treatment with N ω-nitro-l-arginine (l-NNA; 30 μmol/l) and indomethacin (3 μmol/l) reduced the dilation in response to 10 μmol/l ACh from 60 ± 6 to 20 ± 4%. This ni…
Myogenic effects enhance norepinephrine constriction: Inhibition by nitric oxide and felodipine
1998
Myogenic effects enhance norepinephrine constriction: Inhibition by nitric oxide and felodipine. Myogenic, pressure-induced vasoconstriction may amplify the effects of circulating vasoconstrictors. Through intravital microscopy in cremaster arterioles (31 to 115 μm diameter), the relative contribution of myogenic responses (MR) to norepinephrine (NE)-induced constriction and the inhibitor potency of nitric oxide (NO) or a Ca2+ entry blocker (CEB), felodipine (F), were examined. In 24 anesthetized hamsters, a vessel occluder was placed around the aorta to control cremaster vessel inflow pressure (IP). NE infusion increased blood pressure (by 50 ± 2mm Hg) and induced significant constriction …