Non-Destructive Evaluation of Synthetic Tissue Scaffolds With NMR

1998 ◽  
Vol 550 ◽  
Author(s):  
L. Garrido
Keyword(s):  
Open Porosity ◽  
Casting Technique ◽  
Biodegradable Scaffolds ◽  
Porous Matrices ◽  
Magnetic Resonance Imaging Mri ◽  
Non Destructive ◽  
Good Agreement ◽  
Proton Magnetic Resonance Imaging

AbstractProton magnetic resonance imaging (MRI) is applied to determine non–destructively the open porosity of biodegradable scaffolds of poly(3–hydroxybutyrate-–3–hydroxyvalerate) in vitro and tissue infiltration in vivo. Porous matrices with copolymers having 12% and 24% 3–hydroxyvalerate (HV) are prepared using a solvent casting technique. The results of open porosity P(%) measured by MRI (PMRI) show good agreement with those obtained by gravimetry analysis (PGA). Thus, for scaffolds with 12% HV, PMRI = 91.0 ±1.0 (mean ± s.d.) and PGA = 88.0 ± 0.75; and for those with 24% HV, PMRI = 89.4 ±1.3 and PGA = 88.8 ± 1.0. Also, the extent of tissue infiltration in these scaffolds determined by MRI in vivo was similar to that observed by histology. These results illustrate the potential of MRI methods for investigating the behavior of biodegradable scaffolds non-invasively in applications for tissue engineering.

scholarly journals MSCs-engineered biomimetic PMAA nanomedicines for multiple bioimaging-guided and photothermal-enhanced radiotherapy of NSCLC

2021 ◽  
Vol 19 (1) ◽  
Author(s):  
Yipengchen Yin ◽  
Yongjing Li ◽  
Sheng Wang ◽  
Ziliang Dong ◽  
Chao Liang ◽  
...  
Keyword(s):  
Lung Cancer ◽  
Cell Membranes ◽  
Imaging System ◽  
Fluorescence Signal ◽  
Bimodal Imaging ◽  
Red Blood Cell Membranes ◽  
Magnetic Resonance Imaging Mri ◽  
Tumor Accumulation

Abstract Background The recently developed biomimetic strategy is one of the mostly effective strategies for improving the theranostic efficacy of diverse nanomedicines, because nanoparticles coated with cell membranes can disguise as “self”, evade the surveillance of the immune system, and accumulate to the tumor sites actively. Results Herein, we utilized mesenchymal stem cell memabranes (MSCs) to coat polymethacrylic acid (PMAA) nanoparticles loaded with Fe(III) and cypate—an derivative of indocyanine green to fabricate Cyp-PMAA-Fe@MSCs, which featured high stability, desirable tumor-accumulation and intriguing photothermal conversion efficiency both in vitro and in vivo for the treatment of lung cancer. After intravenous administration of Cyp-PMAA-Fe@MSCs and Cyp-PMAA-Fe@RBCs (RBCs, red blood cell membranes) separately into tumor-bearing mice, the fluorescence signal in the MSCs group was 21% stronger than that in the RBCs group at the tumor sites in an in vivo fluorescence imaging system. Correspondingly, the T1-weighted magnetic resonance imaging (MRI) signal at the tumor site decreased 30% after intravenous injection of Cyp-PMAA-Fe@MSCs. Importantly, the constructed Cyp-PMAA-Fe@MSCs exhibited strong photothermal hyperthermia effect both in vitro and in vivo when exposed to 808 nm laser irradiation, thus it could be used for photothermal therapy. Furthermore, tumors on mice treated with phototermal therapy and radiotherapy shrank 32% more than those treated with only radiotherapy. Conclusions These results proved that Cyp-PMAA-Fe@MSCs could realize fluorescence/MRI bimodal imaging, while be used in phototermal-therapy-enhanced radiotherapy, providing desirable nanoplatforms for tumor diagnosis and precise treatment of non-small cell lung cancer.

scholarly journals Immunocompatibility of a new dual modality contrast agent based on radiolabeled iron-oxide nanoparticles

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Maria-Argyro Karageorgou ◽  
Dimosthenis Stamopoulos
Keyword(s):  
Complete Blood Count ◽  
Morphological Characteristics ◽  
Mononuclear Phagocyte ◽  
Dual Modality ◽  
Immunodeficient Mice ◽  
Force Microscopy ◽  
Magnetic Resonance Imaging Mri ◽  
Diagnostic Applications

AbstractRadiolabeled magnetic nanoparticles are promising candidates as dual-modality-contrast-agents (DMCA) for diagnostic applications. The immunocompatibility of a new DMCA is a prerequisite for subsequent in vivo applications. Here, a new DMCA, namely Fe3O4 nanoparticles radiolabeled with 68Ga, is subjected to immunocompatibility tests both in vitro and in vivo. The in vitro immunocompatibility of the DMCA relied on incubation with donated human WBCs and PLTs (five healthy individuals). Optical microscopy (OM) and atomic force microscopy (AFM) were employed for the investigation of the morphological characteristics of WBCs and PLTs. A standard hematology analyzer (HA) provided information on complete blood count. The in vivo immunocompatibility of the DMCA was assessed through its biodistribution among the basic organs of the mononuclear phagocyte system in normal and immunodeficient mice (nine in each group). In addition, Magnetic Resonance Imaging (MRI) data were acquired in normal mice (three). The combined OM, AFM and HA in vitro data showed that although the DMCA promoted noticeable activation of WBCs and PLTs, neither degradation nor clustering were observed. The in vivo data showed no difference of the DMCA biodistribution between the normal and immunodeficient mice, while the MRI data prove the efficacy of the particular DMCA when compared to the non-radiolabeled, parent CA. The combined in vitro and in vivo data prove that the particular DMCA is a promising candidate for future in vivo applications.

In Vitro Degradation of β-TCP/PLLA Scaffolds with Different Proportions of β-TCP

2007 ◽  
Vol 336-338 ◽  
pp. 1545-1548
Author(s):  
Lin Luo ◽  
Guang Fu Yin ◽  
Yun Zhang ◽  
Ya Dong Yao ◽  
Wei Zhong Yang ◽  
...  
Keyword(s):  
Degradation Rate ◽  
Porous Scaffolds ◽  
Carbonate Apatite ◽  
Tissue Formation ◽  
Cellular Attachment ◽  
Biodegradable Scaffolds ◽  
Scaffold Structure ◽  
Mechanical Strengths

Porous biodegradable scaffolds are widely used in bone tissue engineering to provide temporary templates for cellular attachment and matrix synthesis. Ideally, the degradation rate in vivo may be similar or slightly less than that of tissue formation, allowing for the maintenance of the scaffold structure and the mechanical support during early stages of tissue formation. Eventually, the 3-D spaces occupied by the porous scaffolds will be replaced by newly formed tissue. In this work, β-tricalcium phosphate/Poly-L lactide (β-TCP/PLLA) scaffolds with different proportions of β-TCP to PLLA were investigated. The effects of β-TCP proportions on degradation rate and mechanical strengths of the scaffolds were evaluated in simulated body fluid (SBF) at 37°C up to 42 days. Results show that: different proportions of β-TCP to PLLA have significant influence on degradation behaviors of the scaffolds, and mechanical strengths of the scaffolds with weight proportion of β-TCP to PLLA being 2 to 1 are much higher than those of the others during the degradation period. And in this period, the scaffolds biodegrade slowly, and Hydroxyl Carbonate Apatite (HCA) forms in the surface of the material.

Scaffolds in tissue engineering of blood vessels

2010 ◽  
Vol 88 (9) ◽  
pp. 855-873 ◽  
Author(s):  
Divya Pankajakshan ◽  
Devendra K. Agrawal
Keyword(s):  
Tissue Engineering ◽  
Extracellular Matrix ◽  
Blood Vessels ◽  
Vascular Tissue ◽  
Small Diameter ◽  
Biological Scaffolds ◽  
Hemodynamic Forces ◽  
Biodegradable Scaffolds

Tissue engineering of small diameter (<5 mm) blood vessels is a promising approach for developing viable alternatives to autologous vascular grafts. It involves in vitro seeding of cells onto a scaffold on which the cells attach, proliferate, and differentiate while secreting the components of extracellular matrix that are required for creating the tissue. The scaffold should provide the initial requisite mechanical strength to withstand in vivo hemodynamic forces until vascular smooth muscle cells and fibroblasts reinforce the extracellular matrix of the vessel wall. Hence, the choice of scaffold is crucial for providing guidance cues to the cells to behave in the required manner to produce tissues and organs of the desired shape and size. Several types of scaffolds have been used for the reconstruction of blood vessels. They can be broadly classified as biological scaffolds, decellularized matrices, and polymeric biodegradable scaffolds. This review focuses on the different types of scaffolds that have been designed, developed, and tested for tissue engineering of blood vessels, including use of stem cells in vascular tissue engineering.

scholarly journals In Vitro Pharmacodynamic Parameters of Sordarin Derivatives in Comparison with Those of Marketed Compounds against Pneumocystis carinii Isolated from Rats

2000 ◽  
Vol 44 (5) ◽  
pp. 1284-1290 ◽  
Author(s):  
Pablo Aviles ◽  
El-Moukhtar Aliouat ◽  
Antonio Martinez ◽  
Eduardo Dei-Cas ◽  
Esperanza Herreros ◽  
...  
Keyword(s):  
Pneumocystis Carinii ◽  
Maximum Effect ◽  
Drug Concentrations ◽  
Number Of Microorganisms ◽  
Immunosuppressed Patients ◽  
The Hill ◽  
Drug Free ◽  
Good Agreement

ABSTRACT Pneumocystis carinii pneumonia remains one of the most serious complications of immunosuppressed patients. In this study, the in vitro pharmacodynamic parameters of four sordarin derivatives (GM 191519, GM 237354, GM 193663, and GM 219771) have been evaluated by a new quantitative approach and compared with the commercially available drugs pentamidine, atovaquone, and trimethoprim-sulfamethoxazole (TMP-SMX). In vitro activities and in vivo therapeutic efficacies of sordarin derivatives against P. carinii were also evaluated. In vitro activity was determined by the broth microdilution technique, comparing the total number of microorganisms in treated and drug-free cultures by using Giemsa staining. The in vitro maximum effect (E max), the drug concentrations to reach 50% of E max(EC50), and the slope of the dose-response curve were then estimated by the Hill equation (E max sigmoid model). Sordarin derivatives were the most potent agents againstP. carinii, with EC50s of 0.00025, 0.0007, 0.0043, and 0.025 μg/ml for GM 191519, GM 237354, GM 193663, and GM 219771, respectively. The EC50s of pentamidine, atovaquone, and TMP-SMX were 0.025, 0.16, and 26.7/133.5 μg/ml, respectively. The results obtained with this approach showed GM 237354 and GM 191519 to be approximately 35- and 100-fold more active in vitro than pentamidine, the most active marketed compound. All sordarin derivatives tested were at least 5,000-fold more active in vitro than TMP-SMX. The three sordarin derivatives tested in vivo—GM 191519, GM 237354, and GM 219771—showed a marked therapeutic efficacy, defined as reduction of cyst forms per gram of lung. GM 191519 was the most potent (daily dose reducing 50% of the P. carinii burden in the lungs [ED50], 0.05 mg/kg/day) followed by GM 237354 and GM 219771 (ED50s, 0.30 and 0.49 mg/kg/day, respectively). Good agreement between in vitro parameters and in vivo outcome was obtained when P. carinii pneumonia in rats was treated with sordarin derivatives.

scholarly journals Measurement of Novel Dietary Fibers

2004 ◽  
Vol 87 (3) ◽  
pp. 707-717 ◽  
Author(s):  
Barry V McCleary ◽  
Patricia Rossiter
Keyword(s):  
Resistant Starch ◽  
Weight Fraction ◽  
Complete Removal ◽  
High Molecular Weight Fraction ◽  
Interlaboratory Studies ◽  
Human Digestive Tract ◽  
The One ◽  
Good Agreement

Abstract With the recognition that resistant starch (RS) and nondigestible oligosaccharides (NDO) act physiologically as dietary fiber (DF), a need has developed for specific and reliable assay procedures for these components. The ability of AOAC DF methods to accurately measure RS is dependent on the nature of the RS being analyzed. In general, NDO are not measured at all by AOAC DF Methods 985.29 or 991.43, the one exception being the high molecular weight fraction of fructo-oligosaccharides. Values obtained for RS, in general, are not in good agreement with values obtained by in vitro procedures that more closely imitate the in vivo situation in the human digestive tract. Consequently, specific methods for the accurate measurement of RS and NDO have been developed and validated through interlaboratory studies. In this paper, modifications to AOAC fructan Method 999.03 to allow accurate measurement of enzymically produced fructo-oligosaccharides are described. Suggested modifications to AOAC DF methods to ensure complete removal of fructan and RS, and to simplify pH adjustment before amyloglucosidase addition, are also described.

scholarly journals ABC Transporter Inhibition Plus Dexamethasone Enhances the Efficacy of Convection Enhanced Delivery in H3.3K27M Mutant Diffuse Intrinsic Pontine Glioma

Neurosurgery ◽  
2019 ◽  
Vol 86 (5) ◽  
pp. 742-751 ◽  
Author(s):  
Vadim Tsvankin ◽  
Rintaro Hashizume ◽  
Hiroaki Katagi ◽  
James E Herndon ◽  
Christopher Lascola ◽  
...  
Keyword(s):  
Abc Transporter ◽  
Kinase Inhibitor ◽  
Mutant Cell ◽  
Diffuse Intrinsic Pontine Glioma ◽  
Pontine Glioma ◽  
Convection Enhanced Delivery ◽  
P Glycoprotein ◽  
Magnetic Resonance Imaging Mri

Abstract BACKGROUND An impermeable blood–brain barrier and drug efflux via ATP-binding cassette (ABC) transporters such as p-glycoprotein may contribute to underwhelming efficacy of peripherally delivered agents to treat diffuse intrinsic pontine glioma (DIPG). OBJECTIVE To explore the pharmacological augmentation of convection-enhanced delivery (CED) infusate for DIPG. METHODS The efficacy of CED dasatinib, a tyrosine kinase inhibitor, in a transgenic H3.3K27M mutant murine model was assessed. mRNA expression of ABCB1 (p-glycoprotein) was analyzed in 14 tumor types in 274 children. In Vitro viability studies of dasatinib, the p-glycoprotein inhibitor, tariquidar, and dexamethasone were performed in 2 H3.3K27M mutant cell lines. Magnetic resonance imaging (MRI) was used to evaluate CED infusate (gadolinium/dasatinib) distribution in animals pretreated with tariquidar and dexamethasone. Histological assessment of apoptosis was performed. RESULTS Continuous delivery CED dasatinib improved median overall survival (OS) of animals harboring DIPG in comparison to vehicle (39.5 and 28.5 d, respectively; P = .0139). Mean ABCB1 expression was highest in K27M gliomas. In Vitro, the addition of tariquidar and dexamethasone further enhanced the efficacy of dasatinib (P &lt; .001). In Vivo, MRI demonstrated no difference in infusion dispersion between animals pretreated with dexamethasone plus tariquidar prior to CED dasatinib compared to the CED dasatinib. However, tumor apoptosis was the highest in the pretreatment group (P &lt; .001). Correspondingly, median OS was longer in the pretreatment group (49 d) than the dasatinib alone group (39 d) and no treatment controls (31.5 d, P = .0305). CONCLUSION ABC transporter inhibition plus dexamethasone enhances the efficacy of CED dasatinib, resulting in enhanced tumor cellular apoptosis and improved survival in H3.3K27M mutant DIPG.

Mechanism of Action of Progestins in the Treatment of Hormone-dependent Breast Cancer.

1975 ◽  
Vol 61 (6) ◽  
pp. 501-508 ◽  
Author(s):  
Francesco Di Carlo ◽  
Giovanni Pacilio ◽  
Giuseppe Conti
Keyword(s):  
Breast Cancer ◽  
Estrogen Receptors ◽  
Mechanism Of Action ◽  
Mode Of Action ◽  
Binding Capacity ◽  
Specific Receptors ◽  
High Concentrations ◽  
Good Agreement

The in vitro interference of some gestagens with the binding of 3H-17 β-oestradiol to cytosol specific receptors was investigated with a view to elucidating the mechanism of action of progestins in the treatment of human hormone-dependent breast cancer. A decrease (up to 85 %) of oestradiol binding capacity was observed with high concentrations of progesterone, clogestone and medrogestone. These findings are in good agreement with those previously obtained by the same progestins in our laboratory on rat uterine estrogen receptors in vitro or in vivo. These results provide support for the hypothesis that the mode of action of progestins in the therapy of mammary and perhaps uterine carcinomas is to some extent related to the inhibition of oestradiol binding to cytosol specific receptors.

scholarly journals FABRICATION OF BIOADHESIVE OCUSERT WITH DIFFERENT POLYMERS: ONCE A DAY DOSE

2018 ◽  
Vol 10 (6) ◽  
pp. 309
Author(s):  
Aya M. Dawaba ◽  
Hamdy M. Dawaba ◽  
Amal S. M. Abu El-enin ◽  
Maha K. A. Khalifa
Keyword(s):  
In Vitro Release ◽  
Methyl Cellulose ◽  
Storage Period ◽  
Poly Vinyl Alcohol ◽  
Release Kinetic ◽  
Casting Technique ◽  
Process Characterization ◽  
Vitro Release

Objective: The objective of this current study is to fabricate ocuserts to control the drug release from chosen bioadhesive polymeric matrixes to enhance patient compliance. Ciprofloxacin HCl (CFX HCl) was selected as a model drug.Methods: Different bioadhesive polymers with different film forming capabilities namely Hydroxy Propyl Methyl Cellulose (HPMC K4M), Poly Vinyl Alcohol (PVA), Sodium Carboxy Methyl Cellulose (Na CMC), Hydroxy Propyl Cellulose (HPC), Sodium Alginate (Na Alg.), pullulan and Xanthan Gum (XG) in different ratios were used in fabricating ocuserts using solvent-casting technique. Propylene Glycol (PG) was used as a plasticizer to facilitate the fabrication process. Characterization tests of the developed ocuserts were performed as well as bioadhesive tests and in vitro release studies of the incorporated drug. The obtained results were analysed using different release kinetic models. Stability of the selected ocuserts was investigated at 40±0.5 °C and 75±5% Relative Humidity (RH) for three months’ storage period. In vivo ocular irritation test was performed to investigate the safety of the formula in rabbits’ eyes as well as to test the release profile and thus to estimate In vitro In vivo correlation.Results: All the prepared ocuserts showed the uniformity of film characterization and bioadhesion strength ranged from 240±66 and 158±52dyne/cm2. Selected formula from the in vitro release study tested for in vivo study showed the slow release of ciprofloxacin drug up to 24 h with no signs of eye irritancy. Results for In vitro In vivo correlation showed an excellent correlation with R2 value of 0.9982.Conclusion: PVA based ocuserts proven to be a promising once-daily, effective and safe ocular delivery system of the drug.

scholarly journals Bioresorbable optical sensor systems for monitoring of intracranial pressure and temperature

2019 ◽  
Vol 5 (7) ◽  
pp. eaaw1899 ◽  
Author(s):  
Jiho Shin ◽  
Zhonghe Liu ◽  
Wubin Bai ◽  
Yonghao Liu ◽  
Ying Yan ◽  
...  
Keyword(s):  
Optical Sensors ◽  
Diagnostic Information ◽  
Resonance Imaging ◽  
Optical Components ◽  
Continuous Measurements ◽  
Fabry Perot ◽  
Magnetic Resonance Imaging Mri ◽  
Two Dimensional Photonic Crystal

Continuous measurements of pressure and temperature within the intracranial, intraocular, and intravascular spaces provide essential diagnostic information for the treatment of traumatic brain injury, glaucoma, and cardiovascular diseases, respectively. Optical sensors are attractive because of their inherent compatibility with magnetic resonance imaging (MRI). Existing implantable optical components use permanent, nonresorbable materials that must be surgically extracted after use. Bioresorbable alternatives, introduced here, bypass this requirement, thereby eliminating the costs and risks of surgeries. Here, millimeter-scale bioresorbable Fabry-Perot interferometers and two dimensional photonic crystal structures enable precise, continuous measurements of pressure and temperature. Combined mechanical and optical simulations reveal the fundamental sensing mechanisms. In vitro studies and histopathological evaluations quantify the measurement accuracies, operational lifetimes, and biocompatibility of these systems. In vivo demonstrations establish clinically relevant performance attributes. The materials, device designs, and fabrication approaches outlined here establish broad foundational capabilities for diverse classes of bioresorbable optical sensors.

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