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.

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 Fabrication and Characterization of Ta–GelMA–BG Scaffolds by Chemical Crosslinking Processing for Promotion Osteointegration

2021 ◽  
Vol 8 ◽  
Author(s):  
Fujian Zhao ◽  
Xiongfa Ji ◽  
Yang Yan ◽  
Zhen Yang ◽  
Xiaofeng Chen ◽  
...  
Keyword(s):  
Early Stage ◽  
Bone Defects ◽  
Chemical Crosslinking ◽  
Composite Scaffolds ◽  
Load Bearing ◽  
3D Printed ◽  
Fabrication And Characterization ◽  
Cell Adhesion And Proliferation

The repair of bone defects in load-bearing positions still faces great challenges. Tantalum (Ta) has attempted to repair bone defects based on the excellent mechanical properties. However, the osseointegration of Ta needs to be improved due to the lack of osteoinduction. Herein, tantalum–gelatin–methacryloyl–bioactive glass (Ta–GelMA–BG) scaffolds were successfully fabricated by loading BG in 3D-printed Ta scaffolds through a chemical crosslinking method. The results showed that the composite scaffolds have the ability to promote cell adhesion and proliferation. The incorporation of BG resulted in a significant increase in apatite-forming and osteogenesis differentiation abilities. In vivo results indicated that the Ta–GelMA–BG scaffolds significantly enhanced the osteointegration at the early stage after implantation. Overall, the Ta–GelMA–BG scaffolds are a promising platform for the load bearing bone regeneration field.

scholarly journals Light-emitting diode-based transcranial photoacoustic measurement of sagittal sinus oxyhemoglobin saturation in hypoxic neonatal piglets

2020 ◽  
Author(s):  
Jeeun Kang ◽  
Raymond C. Koehler ◽  
Shawn Adams ◽  
Ernest M. Graham ◽  
Emad M. Boctor
Keyword(s):  
Mean Squared Error ◽  
Light Emitting Diode ◽  
Cost Effective ◽  
Preclinical Study ◽  
Light Emitting ◽  
Neonatal Piglets ◽  
Sagittal Sinus ◽  
Photoacoustic Measurement

AbstractWe present a light-emitting diode (LED)-based transcranial photoacoustic measurement (LED-trPA) of oxyhemoglobin (HbO2) saturation at superior sagittal sinus (SSS) in hypoxic neonatal piglets. The optimal LED imaging wavelengths and frame averaging scheme were determined based on in vivo characterization of transcranial sensitivity. Based on the framework (690/850 nm with >20 frame averaging), graded hypoxia was successfully identified in neonatal piglets in vivo with less than 10.0 % of root mean squared error (RMSE). This preclinical study suggests the feasibility of a rapid, cost-effective, and safe LED-trPA monitoring of perinatal hypoxia-ischemia and prompt interventions for clinical use.

scholarly journals Gliadin proteolytical resistant peptides: the interplay between structure and self-assembly in gluten-related disorders

2021 ◽  
Author(s):  
Maria Georgina Herrera ◽  
Veronica Isabel Dodero
Keyword(s):  
Self Assembly ◽  
Early Stage ◽  
Wheat Gluten ◽  
In Vivo Models ◽  
Biophysical Characterization ◽  
Gut Mucosa ◽  
Gliadin Peptides ◽  
Wheat Sensitivity

Abstract In recent years, the evaluation of the structural properties of food has become of crucial importance in the understanding of food-related disorders. One of the most exciting systems is gliadin, a protein in wheat gluten, that plays a protagonist role in gluten-related disorders with a worldwide prevalence of 5%, including autoimmune celiac disease (CeD) (1%) and non-celiac wheat sensitivity (0.5–13%). It is accepted that gliadin is not fully digested by humans, producing large peptides that reach the gut mucosa. The gliadin peptides cross the lamina propria eliciting different immune responses in susceptible patients. Many clinical and biomedical efforts aim to diagnose and understand gluten-related disorders; meanwhile, the early stages of the inflammatory events remain elusive. Interestingly, although the primary sequence of many gliadin peptides is well known, it was only recently revealed the self-assembly capability of two pathogenic gliadin fragments and their connection to the early stage of diseases. This review is dedicated to the most relevant biophysical characterization of the complex gliadin digest and the two most studied gliadin fragments, the immunodominant 33-mer peptide and the toxic p31-43 in connection with inflammation and innate immune response. Here, we want to emphasize that combining different biophysical methods with cellular and in vivo models is of key importance to get an integrative understanding of a complex biological problem, as discussed here.

scholarly journals A “Proteoglycan Targeting Strategy” for the Scintigraphic Imaging and Monitoring of the Swarm Rat Chondrosarcoma Orthotopic Model

Sarcoma ◽  
2011 ◽  
Vol 2011 ◽  
pp. 1-8 ◽  
Author(s):  
Caroline Peyrode ◽  
François Gouin ◽  
Aurélien Vidal ◽  
Philippe Auzeloux ◽  
Sophie Besse ◽  
...  
Keyword(s):  
Bone Scintigraphy ◽  
Late Stage ◽  
Early Stage ◽  
Orthotopic Model ◽  
Scintigraphic Imaging ◽  
Targeting Strategy

Our lab developed99mTc-NTP 15-5 radiotracer as targeting proteoglycans (PGs) for the scintigraphic imaging of joint. This paper reports preclinical results of99mTc-NTP 15-5 imaging of an orthotopic model of Swarm rat chondrosarcoma (SRC).99mTc-NTP 15-5 imaging of SRC-bearing and sham-operated animals was performed and quantified at regular intervals after surgery and compared to bone scintigraphy and tumoural volume. Tumours were characterized by histology and PG assay. SRC exhibited a significant99mTc-NTP 15-5 uptake at very early stage after implant (with tumour/muscle ratio of 1.61 ± 0.14), whereas no measurable tumour was evidenced. As tumour grew, mean tumour/muscle ratio was increased by 2.4, between the early and late stage of pathology. Bone scintigraphy failed to image chondrosarcoma, even at the later stage of study.99mTc-NTP 15-5 imaging provided a suitable set of quantitative criteria for thein vivocharacterization of chondrosarcoma behaviour in bone environment, useful for achieving a greater understanding of the pathology.

scholarly journals In vivo characterization of early-stage radiation skin injury in a mouse model by two-photon microscopy

2016 ◽  
Vol 6 (1) ◽  
Author(s):  
Won Hyuk Jang ◽  
Sehwan Shim ◽  
Taejun Wang ◽  
Yeoreum Yoon ◽  
Won-Suk Jang ◽  
...  
Keyword(s):  
Mouse Model ◽  
Early Stage ◽  
Skin Injury ◽  
Two Photon Microscopy ◽  
Two Photon ◽  
In Vivo Characterization

Functional characterization of human brown adipose tissue metabolism

2020 ◽  
Vol 477 (7) ◽  
pp. 1261-1286 ◽  
Author(s):  
Marie Anne Richard ◽  
Hannah Pallubinsky ◽  
Denis P. Blondin
Keyword(s):  
Adipose Tissue ◽  
Brown Adipose Tissue ◽  
Functional Characterization ◽  
Human Infants ◽  
Positron Emission ◽  
Brown Adipose ◽  
Treatment Of Obesity ◽  
And Function

Brown adipose tissue (BAT) has long been described according to its histological features as a multilocular, lipid-containing tissue, light brown in color, that is also responsive to the cold and found especially in hibernating mammals and human infants. Its presence in both hibernators and human infants, combined with its function as a heat-generating organ, raised many questions about its role in humans. Early characterizations of the tissue in humans focused on its progressive atrophy with age and its apparent importance for cold-exposed workers. However, the use of positron emission tomography (PET) with the glucose tracer [18F]fluorodeoxyglucose ([18F]FDG) made it possible to begin characterizing the possible function of BAT in adult humans, and whether it could play a role in the prevention or treatment of obesity and type 2 diabetes (T2D). This review focuses on the in vivo functional characterization of human BAT, the methodological approaches applied to examine these features and addresses critical gaps that remain in moving the field forward. Specifically, we describe the anatomical and biomolecular features of human BAT, the modalities and applications of non-invasive tools such as PET and magnetic resonance imaging coupled with spectroscopy (MRI/MRS) to study BAT morphology and function in vivo, and finally describe the functional characteristics of human BAT that have only been possible through the development and application of such tools.

Comparison of Immunological and Functional Assays for Measurement of Soluble Fibrin

1995 ◽  
Vol 74 (02) ◽  
pp. 673-679 ◽  
Author(s):  
C E Dempfle ◽  
S A Pfitzner ◽  
M Dollman ◽  
K Huck ◽  
G Stehle ◽  
...  
Keyword(s):  
Venous Thrombosis ◽  
Low Grade ◽  
Plasma Samples ◽  
Normal Range ◽  
Soluble Fibrin ◽  
Discriminating Power ◽  
Fibrin Monomer ◽  
Cerebral Ischemic

SummaryVarious assays have been developed for quantitation of soluble fibrin or fibrin monomer in clinical plasma samples, since this parameter directly reflects in vivo thrombin action on fibrinogen. Using plasma samples from healthy blood donors, patients with cerebral ischemic insult, patients with septicemia, and patients with venous thrombosis, we compared two immunologic tests using monoclonal antibodies against fibrin-specific neo-epitopes, and two functional tests based on the cofactor activity of soluble fibrin complexes in tPA-induced plasminogen activation. Test A (Enzymun®-Test FM) showed the best discriminating power among normal range and pathological samples. Test B (Fibrinostika® soluble fibrin) clearly separated normal range from pathological samples, but failed to discriminate among samples from patients with low grade coagulation activation in septicemia, and massive activation in venous thrombosis. Functional test C (Fibrin monomer test Behring) displayed good discriminating power between normal and pathological range samples, and correlated with test A (r = 0.61), whereas assay D (Coa-Set® Fibrin monomer) showed little discriminating power at values below 10 μg/ml and little correlation with other assays. Standardization of assays will require further characterization of analytes detected.

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