scholarly journals Transcranial photoacoustic characterization of neurovascular physiology during early-stage photothrombotic stroke in neonatal piglets in vivo

2021 ◽  
Author(s):  
Jeeun Kang ◽  
Xiuyun Liu ◽  
Suyi Cao ◽  
Steven R. Zeiler ◽  
Ernest M. Graham ◽  
...  
Keyword(s):  
Oxygen Saturation ◽  
Early Stage ◽  
Tissue Oxygen Saturation ◽  
Triphenyltetrazolium Chloride ◽  
Posterior Cortex ◽  
Receiver Operating Characteristic Curves ◽  
Neonatal Piglets ◽  
Ischemic Region ◽  
Photothrombotic Stroke

Abstract Perinatal ischemic stroke is estimated to occur in 1/2300–1/5000 live births, but early differential diagnosis from global hypoxia-ischemia is often difficult. In this study, we tested the ability of a hand-held transcranial photoacoustic (PA) imaging probe to non-invasively detect a focal photothrombotic stroke (PTS) within 2 hours of stroke onset in a gyrencephalic piglet brain. 17 stroke lesions of approximately 1-cm2 area were introduced randomly in anterior or posterior cortex via the light/dye PTS technique in anesthetized neonatal piglets (n = 11). The contralateral non-ischemic region served as control tissue for discrimination contrast for the PA hemoglobin metrics: oxygen saturation, total hemoglobin (tHb), and individual quantities of oxygenated and deoxygenated hemoglobin (HbO2 and HbR). The PA-derived tissue oxygen saturation at 2 hours yielded a significant separation between control and affected regions-of-interest (p < 0.0001), which were well matched with 24-hr post-stroke cerebral infarction confirmed in the triphenyltetrazolium chloride-stained image. The quantity of HbO2 also displayed a significant contrast (p = 0.021), whereas tHb and HbR did not. The analysis on receiver operating characteristic curves and multivariate data analysis also agreed with the results above. This study shows that a hand-held transcranial PA neuroimaging device can detect a regional thrombotic stroke in the cerebral cortex of a neonatal piglet. In particular, we conclude that the oxygen saturation metric can be used alone to identify regional stroke lesions. The lack of change in tHb may be related to arbitrary hand-held imaging configuration and/or entrapment of red blood cells within the thrombotic stroke.

scholarly journals Transcranial photoacoustic characterization of neurovascular physiology during early-stage photothrombotic stroke in neonatal piglets in vivo

2021 ◽  
Author(s):  
Jeeun Kang ◽  
Xiuyun Liu ◽  
Suyi Cao ◽  
Steven R Zeiler ◽  
Ernest M Graham ◽  
...  
Keyword(s):  
Operating Characteristic ◽  
Early Stage ◽  
Triphenyltetrazolium Chloride ◽  
Posterior Cortex ◽  
Receiver Operating Characteristic Curves ◽  
Neonatal Piglets ◽  
Ischemic Region ◽  
Photothrombotic Stroke

Perinatal ischemic stroke is estimated to occur in 1/2300-1/5000 live births, but early differential diagnosis from global hypoxia-ischemia is often difficult. In this study, we tested the ability of a hand-held transcranial photoacoustic (PA) imaging to non-invasively detect a focal photothrombotic stroke (PTS) within 2 hours of stroke onset in a gyrencephalic piglet brain. 17 stroke lesions of approximately 1-cm2 area were introduced randomly in anterior or posterior cortex via the light/dye PTS technique in anesthetized neonatal piglets (n = 11). The contralateral non-ischemic region served as control tissue for discrimination contrast for the PA hemoglobin metrics: HbO2 saturation, total hemoglobin (tHb), and individual quantities of oxygenated and deoxygenated hemoglobin (HbO2 and HbR). The PA-derived tissue HbO2 saturation at 2 hours yielded a significant separation between control and affected regions-of-interest (p < 0.0001), which were well matched with 24-hr post-stroke cerebral infarction confirmed in the triphenyltetrazolium chloride (TTC)-stained image. The quantity of HbO2 also displayed a significant contrast (p = 0.021), whereas tHb and HbR did not. The analysis on receiver operating characteristic curves and multivariate data analysis also agreed with the results above. This study shows that a hand-held transcranial PA neuroimaging can detect a regional thrombotic stroke in cerebral cortex of a neonatal piglet. In particular, we conclude that the HbO2 saturation metric can be used alone to identify regional stroke lesions. The lack of change in tHb may be related to arbitrary hand-held imaging configuration and/or entrapment of red blood cells within the thrombotic stroke.

Evaluation of changes in the haemoglobin of skin and muscle tissue of the calf, as induced by topical application of a nonivamide/nicoboxil cream

2014 ◽  
Vol 92 (2) ◽  
pp. 149-154 ◽  
Author(s):  
Jan M. Warnecke ◽  
Thomas Wendt ◽  
Stefan Winkler ◽  
Matthias Schak ◽  
Thorsten Schiffer ◽  
...  
Keyword(s):  
Blood Flow ◽  
Oxygen Saturation ◽  
Optical Spectroscopy ◽  
Topical Application ◽  
Near Infrared ◽  
Nir Spectroscopy ◽  
Topical Administration ◽  
Tissue Oxygen Saturation ◽  
Tissue Oxygen

Topical agents like nonivamide and nicoboxil induce hyperaemisation and increase cutaneous blood flow and temperature. This study aimed to determine the effects of a nonivamide–nicoboxil cream on haemodynamics in the skin and calf muscle, via optical spectroscopy, discriminating between the changes for skin and muscle. Optical spectroscopy was applied in the visible (VIS) and near-infrared (NIR) wavelength range. The study determined the effect of the cream on changes in oxygenated (ΔoxyHb) and deoxygenated (ΔdeoxyHb) haemoglobin in skin and muscle, as well as on tissue oxygen saturation (SO2) in the skin of 14 healthy subjects. The left and right calves of the subjects were either treated with nonivamide–nicoboxil cream or were sham-administered. NIR spectroscopy allows noninvasive in-vivo examination of the oxygenation of human skeletal muscle. Topical administration of the nonivamide–nicoboxil cream significantly increased the concentration of oxygenated haemoglobin and tissue oxygen saturation in the skin, as well as the concentration of oxygenated haemoglobin in the muscle of the treated legs after 15 min, but with stronger and faster effects in the skin. The topical application of the nonivamide–nicoboxil cream increased blood flow in (smaller vessels of) the skin and muscle tissues.

scholarly journals In Vivo Assessment of Hypoxia Levels in Pancreatic Tumors Using a Dual-Modality Ultrasound/Photoacoustic Imaging System

Micromachines ◽  
2021 ◽  
Vol 12 (6) ◽  
pp. 668
Author(s):  
Yuhling Wang ◽  
De-Fu Jhang ◽  
Chia-Hua Tsai ◽  
Nai-Jung Chiang ◽  
Chia-Hui Tsao ◽  
...  
Keyword(s):  
Tumor Growth ◽  
Oxygen Saturation ◽  
Pancreatic Tumor ◽  
Tissue Oxygenation ◽  
Imaging System ◽  
Tissue Oxygen Saturation ◽  
Functional Information ◽  
Tissue Oxygen ◽  
Dual Modality

Noninvasive anatomical and functional imaging has become an essential tool to evaluate tissue oxygen saturation dynamics in preclinical or clinical studies of hypoxia. Our dual-wavelength technique for photoacoustic (PA) imaging based on the differential absorbance spectrum of oxyhemoglobin (oxy-Hb) and deoxyhemoglobin (deoxy-Hb) can quantify tissue oxygen saturation using the intrinsic contrast property. PA imaging of tissue oxygen saturation can be used to monitor tumor-related hypoxia, which is a particularly relevant functional parameter of the tumor microenvironment that has a strong influence on tumor aggressiveness. The simultaneous acquisition of anatomical and functional information using dual-modality ultrasound (US) and PA imaging technology enhances the preclinical applicability of the method. Here, the developed dual-modality US/PA system was used to measure relative tissue oxygenation using the dual-wavelength technique. Tissue oxygen saturation was quantified in a pancreatic tumor mouse model. The differences in tissue oxygenation were detected by comparing pancreatic samples from normal and tumor-bearing mice at various time points after implantation. The use of an in vivo pancreatic tumor model revealed changes in hypoxia at various stages of tumor growth. The US/PA imaging data positively correlated with the results of immunohistochemical staining for hypoxia. Thus, our dual-modality US/PA imaging system can be used to reliably assess and monitor hypoxia in pancreatic tumor mouse models. These findings enable the use of a combination of US and PA imaging to acquire anatomical and functional information on tumor growth and to evaluate treatment responses in longitudinal preclinical studies.

scholarly journals Tissue Oxygen Saturation Mapping with Magnetic Resonance Imaging

2014 ◽  
Vol 34 (9) ◽  
pp. 1550-1557 ◽  
Author(s):  
Thomas Christen ◽  
Pierre Bouzat ◽  
Nicolas Pannetier ◽  
Nicolas Coquery ◽  
Anaïck Moisan ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Oxygen Saturation ◽  
Tissue Oxygen Saturation ◽  
Blood Oxygen ◽  
Oxygen Level ◽  
Resonance Imaging ◽  
Tissue Oxygen ◽  
Invasive Approach

A quantitative estimate of cerebral blood oxygen saturation is of critical importance in the investigation of cerebrovascular disease. While positron emission tomography can map in vivo the oxygen level in blood, it has limited availability and requires ionizing radiation. Magnetic resonance imaging (MRI) offers an alternative through the blood oxygen level-dependent contrast. Here, we describe an in vivo and non-invasive approach to map brain tissue oxygen saturation ( StO2) with high spatial resolution. StO2 obtained with MRI correlated well with results from blood gas analyses for various oxygen and hematocrit challenges. In a stroke model, the hypoxic areas delineated in vivo by MRI spatially matched those observed ex vivo by pimonidazole staining. In a model of diffuse traumatic brain injury, MRI was able to detect even a reduction in StO2 that was too small to be detected by histology. In a F98 glioma model, MRI was able to map oxygenation heterogeneity. Thus, the MRI technique may improve our understanding of the pathophysiology of several brain diseases involving impaired oxygenation.

Adenosine Diphosphate (ADP)-Induced ⍺-Granules Release from Platelets of Native Whole Blood Is Reduced by Ticlopidine but Not by Aspirin or Dipyridamole

1986 ◽  
Vol 56 (02) ◽  
pp. 147-150 ◽  
Author(s):  
V Pengo ◽  
M Boschello ◽  
A Marzari ◽  
M Baca ◽  
L Schivazappa ◽  
...  
Keyword(s):  
Whole Blood ◽  
Light Transmission ◽  
Ex Vivo ◽  
Early Stage ◽  
Shape Change ◽  
Adenosine Diphosphate ◽  
Dose Dependent ◽  
Plateletderived Growth Factor ◽  
Platelet Shape

SummaryA brief contact between native whole blood and ADP promotes a dose-dependent release of platelet a-granules without a fall in the platelet number. We assessed the “ex vivo” effect of three widely used antiplatelet drugs, aspirin dipyridamole and ticlopidine, on this system. Aspirin (a single 800 mg dose) and dipyridamole (300 mg/die for four days) had no effect, while ticlopidine (500 mg/die for four days) significantly reduced the a-granules release for an ADP stimulation of 0.4 (p <0.02), 1.2 (p <0.01) and 2 pM (p <0.01). No drug, however, completeley inhibits this early stage of platelet activation. The platelet release of α-granules may be related to platelet shape change of the light transmission aggregometer and may be important “in vivo” by enhancing platelet adhesiveness and by liberating the plateletderived growth factor.

scholarly journals Bovine Milk-Derived Emulsifiers Increase Triglyceride Absorption in Newborn Formula-Fed Pigs

Nutrients ◽  
2021 ◽  
Vol 13 (2) ◽  
pp. 410 ◽  
Author(s):  
Kristine Bach Korsholm Knudsen ◽  
Christine Heerup ◽  
Tine Røngaard Stange Jensen ◽  
Xiaolu Geng ◽  
Nikolaj Drachmann ◽  
...  
Keyword(s):  
Milk Fat ◽  
Bovine Milk ◽  
In Vitro Digestion ◽  
Lipid Absorption ◽  
Lipid Digestion ◽  
Soy Lecithin ◽  
Neonatal Piglets ◽  
Milk Fat Globule Membranes

Efficient lipid digestion in formula-fed infants is required to ensure the availability of fatty acids for normal organ development. Previous studies suggest that the efficiency of lipid digestion may depend on whether lipids are emulsified with soy lecithin or fractions derived from bovine milk. This study, therefore, aimed to determine whether emulsification with bovine milk-derived emulsifiers or soy lecithin (SL) influenced lipid digestion in vitro and in vivo. Lipid digestibility was determined in vitro in oil-in-water emulsions using four different milk-derived emulsifiers or SL, and the ultrastructural appearance of the emulsions was assessed using electron microscopy. Subsequently, selected emulsions were added to a base diet and fed to preterm neonatal piglets. Initially, preterm pigs equipped with an ileostomy were fed experimental formulas for seven days and stoma output was collected quantitatively. Next, lipid absorption kinetics was studied in preterm pigs given pure emulsions. Finally, complete formulas with different emulsions were fed for four days, and the post-bolus plasma triglyceride level was determined. Milk-derived emulsifiers (containing protein and phospholipids from milk fat globule membranes and extracellular vesicles) showed increased effects on fat digestion compared to SL in an in vitro digestion model. Further, milk-derived emulsifiers significantly increased the digestion of triglyceride in the preterm piglet model compared with SL. Ultra-structural images indicated a more regular and smooth surface of fat droplets emulsified with milk-derived emulsifiers relative to SL. We conclude that, relative to SL, milk-derived emulsifiers lead to a different surface ultrastructure on the lipid droplets, and increase lipid digestion.

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