Sustained dasatinib treatment prevents early fibrotic changes following ocular trauma.

PURPOSE: Posterior ocular trauma and the subsequent fibrotic retinal complication termed proliferative vitreoretinopathy (PVR) are leading causes of blindness in children and young adults. A previous study suggested that changes occurring within the first month post-trauma can lead to development of PVR later. The aim of this study was to examine the effect of dasatinib, a tyrosine kinase inhibitor clinically used to treat chronic myeloid leukemia, on fibrotic changes occurring within the first month following ocular trauma. METHODS: A previously established swine ocular trauma model that mimics both contusion and penetrating injuries was used. Dasatinib was administered on days 4 and 18 post-trauma via intravitreal injection of either bolus solution or suspension of a sustained release system incorporated in biodegradable poly (lactic-co-glycolic acid) (PLGA) nanoparticles. Animals were followed up to day 32, and the development of traction full-thickness fold in the posterior retina was assessed. RESULTS: A full-thickness retinal fold extending from the wound site developed in 3 out of 4 control eyes injected with PLGA nanoparticles alone at 1 month. Administration of dasatinib solution had little preventative effect with 6 out of 7 eyes developing a fold. In contrast, dasatinib-incorporated PLGA nanoparticle injection significantly reduced the incidence of fold to 1 out of 10 eyes. CONCLUSIONS: Injection of dasatinib-incorporated PLGA significantly reduced early fibrotic retinal changes which eventually lead to PVR following posterior ocular trauma. Thus, our sustained dasatinib release system can potentially be used to both prevent and/or broaden the surgical treatment window for PVR.

A prospective single-center observational study to assess the efficacy of the second-generation supraglottic airway device I-gel in laparoscopic surgeries in children.

BACKGROUND AND AIMS: Supraglottic airways used in pediatric surgeries are associated with a lesser number of postanesthesia respiratory complications. However, there is limited literature on the use of i-gel for pediatric laparoscopic surgery. The aim of this study is to assess the adequacy of ventilation of i-gel for pediatric laparoscopic surgery and note any associated adverse event. MATERIAL AND METHODS: This is a single-centered prospective observational study including 119 children, aged 6 months to 18 years, scheduled for laparoscopic surgery, during a 9-month period, in a tertiary care center. I-gel was used for positive pressure ventilation, and if the post-insertion oropharyngeal seal pressure was <25 cm H2O, it was replaced with a tracheal tube. Adequacy of ventilation and adverse events were noted. RESULTS: Data from 102 cases were analyzed (17 cases excluded: tracheal intubation in 11; missing data in 6 cases). The mean oropharyngeal seal pressure was 34.2 ± 5.2 cm H2O and mean airway pressure was 16.1 ± 2.4 cm H2O. The adverse events included transient cough (10.7%), sore throat (4.9%), and desaturation (3.9%). There was no sign of respiratory distress during the recovery and no intervention was required in any child postoperatively. CONCLUSION: I-gel provided adequate ventilation of the lungs in children undergoing laparoscopic surgery with no major adverse event.

Influenza virus immunosensor with an electro-active optical waveguide under potential modulation.

Here we report the development of a novel immunosensor-based strategy for label-free detection of viral pathogens by incorporating a sandwich bioassay onto a single-mode, electro-active, integrated optical waveguide (EA-IOW). Our strategy begins with the functionalization of the electro-active waveguide surface with a capture antibody aimed at a specific virus antigen. Once the target antigen is bound to the photonic interface, it promotes the binding of a secondary antibody that has been labeled with a methylene blue (MB) dye. The MB is a redox-active probe whose optical absorption can be electrically modulated and interrogated with high sensitivity by a propagating waveguide mode. In this effort, we have targeted the hemagglutinin (HA) protein from the H5N1 avian influenza A virus to demonstrate the capabilities of the EA-IOW device for detection and quantification of an important antigen. Our initial results for the HA H5N1 influenza virus show a remarkable limit of detection in the pico-molar range.

Release-Modulated Antioxidant Activity of a Composite Curcumin-Chitosan Polymer.

Curcumin is known to have immense therapeutic potential but is hindered by poor solubility and rapid degradation in solution. To overcome these shortcomings, curcumin has been conjugated to chitosan through a pendant glutaric anhydride linker using amide bond coupling chemistry. The hybrid polymer has been characterized by UV-visible, fluorescence, and infrared spectroscopies as well as zeta potential measurements and SEM imaging. The conjugation reactivity was confirmed through gel permeation chromatography and quantification of unconjugated curcumin. An analogous reaction of curcumin with glucosamine, a small molecule analogue for chitosan, was performed and the purified product characterized by mass spectrometry, UV-visible, fluorescence, and infrared spectroscopies. Conjugation of curcumin to chitosan has greatly improved curcumin aqueous solubility and stability, with no significant curcumin degradation detected after one month in solution. The absorbance and fluorescence properties of curcumin are minimally perturbed (λmax shifts of 2 and 5 nm, respectively) by the conjugation reaction. This conjugation strategy required use of one out of two curcumin phenols (one of the main antioxidant functional groups) for covalent linkage to chitosan, thus temporarily attenuating its antioxidant capacity. Hydrolysis-based release of curcumin from the polymer, however, is accompanied by full restoration of curcumin's antioxidant potential. Antioxidant assays show that curcumin radical scavenging potential is reduced by 40% after conjugation, but that full antioxidant potential is restored upon hydrolytic release from chitosan. Release studies show that curcumin is released over 19 days from the polymer and maintains a concentration of 0.23 ± 0.12 µM curcumin/mg polymer/mL solution based on 1% curcumin loading on the polymer. Release studies in the presence of carbonic anhydrase, an enzyme with known phenolic esterase activity, show no significant difference from nonenzymatic release studies, implying that simple ester hydrolysis is the dominant release mechanism. Conjugation of curcumin to chitosan through a phenol ester modification provides improved stability and solubility to curcumin, with ester hydrolysis restoring the full antioxidant potential of curcumin.

Selective and reversible base-induced elimination of a ruthenium dithioether yields a vinyl metallosulfonium complex.

Chemical oxidation of tris(2-diphenylphosphinebenzenethiolato)ruthenate(II) [Ru-1](-) with ferrocenium hexafluorophosphate in the presence of ethylene yields [(2-diphenylphosphinebenzenethiolato)(ethane-1,2-diylbis(thio-2,1-phenylene)diphenylphosphine)ruthenium(II)] hexafluorophosphate, [Ru-1·C(2)H(4)]PF(6), from addition of the alkene across cis sulfur sites. The [Ru-1·C(2)H(4)](+) complex displays a single redox couple at +794 mV versus ferrocenium/ferrocene. (1)H NMR of [Ru-1·C(2)H(4)](+) displays ethylene resonances at δ = 1.29 (td, 1H), 1.59 (td, 1H), 2.78 (dd, 1H), and 3.03 (dd, 1H). In the presence of base [Ru-1·C(2)H(4)](+) is selectively deprotonated at the pseudoequatorial proton on the carbon α to the sulfur trans to phosphorus, yielding the vinyl metallosulfonium derivative [Ru-1·C(2)H(3)]. (1)H and (31)P NMR spectra of [Ru-1·C(2)H(3)] are temperature dependent, associated with inversion of the sulfur lone pair at the vinyl metallosulfonium. The activation energy for the fluxional process calculated using density functional theory (B3LYP/LANL2DZ+6-31g) of 14.36 kcal/mol is consistent with the experimentally determined value of 13.08 kcal/mol. The complex [Ru-1·C(2)H(3)] crystallizes as yellow blocks in the triclinic space group P-1 with unit cell dimensions of a = 11.2718(5) Å, b =12.0524(3) Å, c = 23.6075(10) Å, α = 101.715(3)°, ß = 98.154(4)°, and γ = 105.209(3)°. Addition of hydrochloric acid to [Ru-1·C(2)H(3)] regenerates [Ru-1·C(2)H(4)](+). Addition of DCl confirms the selectivity of this reverse reaction.

Optimization of Tumor Targeting Gold Nanoparticles for Glioblastoma Applications.

Glioblastoma brain tumors represent an aggressive form of gliomas that is hallmarked by being extremely invasive and aggressive due to intra and inter-tumoral heterogeneity. This complex tumor microenvironment makes even the newer advancements in glioblastoma treatment less effective long term. In developing newer treatment technologies against glioblastoma, one should tailor the treatment to the tumor microenvironment, thus allowing for a more robust and sustained anti-glioblastoma effect. Here, we present a novel gold nanoparticle therapy explicitly designed for bioactivity against glioblastoma representing U87MG cell lines. We employ standard conjugation techniques to create oligonucleotide-coated gold nanoparticles exhibiting strong anti-glioblastoma behavior and optimize their design to maximize bioactivity against glioblastoma. Resulting nanotherapies are therapy specific and show upwards of 75% inhibition in metabolic and proliferative activity with stark effects on cellular morphology. Ultimately, these gold nanotherapies are a good base for designing more multi-targeted approaches to fighting against glioblastoma.

Long-term stabilization of DNA at room temperature using a one-step microwave assisted process.

Long-term stabilization of DNA is needed for forensic, clinical, in-field operations and numerous other applications. Although freezing (<-20 °C) and dry storage are currently the preferential methods for long-term storage, a noticeable pre-analytical degradation of DNA over time, upfront capital investment and recurring costs have demonstrated a need for an alternative long-term room-temperature preservation method. Herein, we report a novel, fast (~5 min) silica sol-gel preparation method using a standard microwave-initiated polymerization reaction amenable to stabilization of DNA. The method involves use of one chemical, tetramethoxy silane (TMOS) and eliminates the use of alcohol as co-solvent and catalysts such as acids. In addition, the process involves minimal technical expertise, thus making it an ideal choice for resource-challenged countries and in-field applications. The sol-gel is capable to store and stabilize Escherichia coli DNA in ambient conditions for 210 days. DNA recovered from the sol-gel showed no significant nucleolytic and/or oxidative degradation, outperforming conventional storage conditions at -20 °C, and reported state-of-the-art technology. Supplementary Information: The online version contains supplementary material available at 10.1007/s42247-021-00208-3.

Enhancing the compatibility of BioCaRGOS silica sol-gel technology with ctDNA extraction and droplet digital PCR (ddPCR) analysis.

Previously, our group had demonstrated long term stabilization of protein biomarkers using BioCaRGOS, a silica sol-gel technology. Herein, we describe workflow modifications to allow for extraction of cell free DNA (cfDNA) from primary samples containing working concentrations of BioCaRGOS, as well as the compatibility of BioCaRGOS with droplet digital PCR (ddPCR) analysis for pancreatic cancer biomarkers i.e., KRAS circulating tumor DNA (ctDNA). Preliminary attempts to extract ctDNA from BioCaRGOS containing samples demonstrated interference in the extraction of primary samples and the interference with ddPCR analysis when BioCaRGOS was directly introduced to stabilize sample extracts. In our modified technique, we have minimized the interference caused by methanol with ddPCR by complete removal of methanol from the activated BioCaRGOS formulation prior to addition to the biospecimen or ctDNA extract. Interference of the silica matrix present in BioCaRGOS with ctDNA extraction was eliminated through the introduction of invert filtration of the sample prior to extraction. These modifications to the workflow of BioCaRGOS containing samples allow for use of BioCaRGOS for stabilization of trace quantities of nucleic acid biomarkers such as plasma ctDNA, while retaining the capability to extract the biomarker and quantify based on ddPCR.

Long term storage of miRNA at room and elevated temperatures in a silica sol-gel matrix.

Storage of biospecimens in their near native environment at room temperature can have a transformative global impact, however, this remains an arduous challenge to date due to the rapid degradation of biospecimens over time. Currently, most isolated biospecimens are refrigerated for short-term storage and frozen (-20 °C, -80 °C, liquid nitrogen) for long-term storage. Recent advances in room temperature storage of purified biomolecules utilize anhydrobiosis. However, a near aqueous storage solution that can preserve the biospecimen nearly "as is" has not yet been achieved by any current technology. Here, we demonstrate an aqueous silica sol-gel matrix for optimized storage of biospecimens. Our technique is facile, reproducible, and has previously demonstrated stabilization of DNA and proteins, within a few minutes using a standard benchtop microwave. Herein, we demonstrate complete integrity of miRNA 21, a highly sensitive molecule at 4, 25, and 40 °C over a period of ∼3 months. In contrast, the control samples completely degrade in less than 1 week. We attribute excellent stability to entrapment of miRNA within silica-gel matrices.

Bio-CaRGOS: capture and release gels for optimized storage of hemoglobin.

Room temperature biospecimen storage for prolonged periods is essential to eliminate energy consumption by ultra-low freezing or refrigeration-based storage techniques. State of the art practices that sufficiently minimize the direct or hidden costs associated with cold-chain logistics include ambient temperature storage of biospecimens (i.e., DNA, RNA, proteins, lipids) in the dry state. However, the biospecimens are still well-exposed to the stress associated with drying and reconstitution cycles, which augments the pre-analytical degradation of biospecimens prior to their downstream processing. An aqueous storage solution that can eliminate these stresses which are correlated to several cycles of drying/rehydration or freezing of biospecimens, is yet to be achieved by any current technology. In our study, we have addressed this room temperature biospecimen-protection challenge using aqueous capture and release gels for optimized storage (Bio-CaRGOS) of biospecimens. Herein, we have demonstrated a single-step ∼95% recovery of a metalloprotein hemoglobin at room temperature using a cost-effective standard microwave-based aqueous formulation of Bio-CaRGOS. Although hemoglobin samples are currently stored at sub-zero or under refrigeration (4 °C) conditions to avoid loss of integrity and an unpredictable diagnosis during their downstream assays, our results have displayed an unprecedented room temperature integrity preservation of hemoglobin. Bio-CaRGOS formulations efficiently preserve hemoglobin in its native state, with single-step protein recovery of ∼95% at ambient conditions (1 month) and ∼96% (7 months) under refrigeration conditions. In contrast, two-thirds of the control samples degrade under ambient (1 month) and refrigeration (7 months) settings.

A Comparative Evaluation of Two Commonly Used GP Solvents on Different Epoxy Resin-based Sealers: An In Vitro Study.

AIM: This study evaluates epoxy resin-based sealers after their final set, immersed in Endosolve-R or xylene for 1-2 minutes, for its easy removal mechanically after softening. MATERIALS AND METHODS: Sixty Teflon molds were grouped with 20 samples in each of the three commercially available sealers, i.e., AH 26, AH Plus, and Adseal. The sealers were put in the specific molds after their manipulation as per the instructions given in the literature by the manufacturer. They were allowed to harden for 2 weeks at 37°C in 100% humidity. Two subgroups, A-Xylene and B-Endosolv-R, of 10 samples each, were formed from 20 set specimens based on solvents to which they were immersed for 1 and 2 minutes, respectively. The data obtained was subjected to the Mauchly's test one-way ANOVA and two-way ANOVA for analysis. RESULTS: It was proved that for all the sealers immersed in solvents, there was a significant reduction in the mean Vickers hardness as the time increases. There was a significant difference in the initial hardness between the mentioned sealers with AH plus showing the highest followed by AH 26 and Adseal showing the lowest. AH Plus and Adseal sealers were softened by xylene after 2 minutes of their initial microhardness (p < 0.001); least effect was seen on AH 26. After 2 minutes, Endosolv-R softened initial microhardness of all the three sealers (p < 0.001). CONCLUSION: It was concluded that Endosolv-R was more effective in softening the epoxy-based resin sealer than xylene, after 2 minutes of exposure. HOW TO CITE THIS ARTICLE: Tyagi S, Choudhary E, Choudhary A, et al. A Comparative Evaluation of Two Commonly Used GP Solvents on Different Epoxy Resin-based Sealers: An In Vitro Study. Int J Clin Pediatr Dent 2020;13(1):35-37.

Radiation-induced curcumin release from curcumin-chitosan polymer films.

The probability of human exposure to damaging radiation is increased in activities associated with long-term space flight, medical radiation therapies, and responses to nuclear accidents. However, the development of responsive countermeasures to combat radiation damage to biological tissue is lagging behind rates of human exposure. Herein, we report a radiation-responsive drug delivery system that releases doses of curcumin from a chitosan polymer/film in response to low level gamma radiation exposure. As a fibrous chitosan-curcumin polymer, 1 Gy gamma irradiation (137Cs) released 5 ± 1% of conjugated curcumin, while 6 Gy exposure releases 98 ± 1% of conjugated curcumin. The same polymer was formed into a film through solvent casting. The films showed similar, albeit attenuated behavior in water (100% released) and isopropyl alcohol (32% released) with statistically significant drug release following 2 Gy irradiation. ATR FT-IR studies confirmed glycosidic bond cleavage in the chitosan-curcumin polymer in response to gamma radiation exposure. Similar behavior was noted upon exposure of the polymer to 20 cGy (1 GeV amu-1, at 20 cGy min-1) high linear energy transfer (LET) 56Fe radiation based on FTIR studies. Density Functional Theory calculations indicate homolytic bond scission as the primary mechanism for polymer disintegration upon radiation exposure. Films did not change in thickness during the course of radiation exposure. The successful demonstration of radiation-triggered drug release may lead to new classes of radio-protective platforms for developing countermeasures to biological damage from ionizing radiation.

Radiographic Evaluation of the Hyoid Bone Position and Pharyngeal Airway Depth in Anteroposterior Dysplasia.

INTRODUCTION: The pharyngeal airway, tongue, and hyoid bone are correlated. The hyoid bone is connected to the pharynx, mandible, and cranium through muscles and ligaments and its position with respect to them determines the tongue posture and function. It also plays an important role in maintaining the airway and upright natural head position. Different skeletal patterns have different morphologies and shapes of the mandible, which might be affected by the position of the hyoid bone and the pharyngeal airway depth. This cephalometric study was conducted to relate the pharyngeal airway depth and the hyoid bone position of different skeletal patterns in sagittal dimension, and it determines and compares the linear parameters of the pharyngeal airway depth in Class I, II, and III malocclusion groups and anteroposterior, vertical, and angular positions of the hyoid bone positions in Class I, II, and III malocclusion groups. MATERIALS AND METHODS: Lateral cephalometric radiographs selected for study were divided into three groups of 30 samples each based on ANB angle and ß angle into skeletal Class I, Class II, and Class III, respectively. Five linear measurements for the pharyngeal airway depth, four linear measurements for anteroposterior position, two linear measurements for vertical position, and one angular measurement for angular hyoid bone position were made. RESULTS: The pharyngeal airway depth was found to show no statistically significant difference between Class I and Class III malocclusions. The pharyngeal airway depth in Class II malocclusion was found to be statistically smaller at D1 as compared to that in Class I and Class III malocclusions, whereas it remained the same at the rest of the locations measured, i.e., D2, D3, D4, and D5. The Class III malocclusion group showed a significant statistical difference in the anteroposterior hyoid bone position at all levels (i.e., H1, H2, H3, and H4) as compared to the Class II malocclusion group, whereas it showed a statistically significant difference as compared to the Class I malocclusion group at H1 and H3. The angular inclination of the hyoid bone in the Class II malocclusion group showed a statistically significant difference with the Class I and Class III malocclusion group but the Class III malocclusion group showed no significant difference statistically when compared to the Class I malocclusion group. CONCLUSION: The pharyngeal airway depth in the Class II malocclusion group was also found to be narrower at the superiormost level measured at the posterior nasal spine from the posterior pharyngeal wall. The hyoid bone position was variable in angular and anteroposterior dimensions among different malocclusion groups. HOW TO CITE THIS ARTICLE: Chauhan R, Bagga DK, et al. Radiographic Evaluation of the Hyoid Bone Position and Pharyngeal Airway Depth in Anteroposterior Dysplasia. Int J Clin Pediatr Dent 2019;12(2):101-106.

Targeted Gold Nanoparticle⁻Oligonucleotide Contrast Agents in Combination with a New Local Voxel-Wise MRI Analysis Algorithm for In Vitro Imaging of Triple-Negative Breast Cancer.

Gold nanoparticles (GNPs) have tremendous potential as cancer-targeted contrast agents for diagnostic imaging. The ability to modify the particle surface with both disease-targeting molecules (such as the cancer-specific aptamer AS1411) and contrast agents (such as the gadolinium chelate Gd(III)-DO3A-SH) enables tailoring the particles for specific cancer-imaging and diagnosis. While the amount of image contrast generated by nanoparticle contrast agents is often low, it can be augmented with the assistance of computer image analysis algorithms. In this work, the ability of cancer-targeted gold nanoparticle-oligonucleotide conjugates to distinguish between malignant (MDA-MB-231) and healthy cells (MCF-10A) is tested using a T1-weighted image analysis algorithm based on three-dimensional, deformable model-based segmentation to extract the Volume of Interest (VOI). The gold nanoparticle/algorithm tandem was tested using contrast agent GNP-Gd(III)-DO3A-SH-AS1411) and nontargeted c-rich oligonucleotide (CRO) analogs and control (CTR) counterparts (GNP-Gd(III)-DO3A-SH-CRO/CTR) via in vitro studies. Remarkably, the cancer cells were notably distinguished from the nonmalignant cells, especially at nanomolar contrast agent concentrations. The T1-weighted image analysis algorithm provided similar results to the industry standard Varian software interface (VNMRJ) analysis of T1 maps at micromolar contrast agent concentrations, in which the VNMRJ produced a 19.5% better MRI contrast enhancement. However, our algorithm provided more sensitive and consistent results at nanomolar contrast agent concentrations, where our algorithm produced ~500% better MRI contrast enhancement.

Probing the reactivity and radical nature of oxidized transition metal-thiolate complexes by mass spectrometry.

Transition metal thiolate complexes such as [PPN](+)[RuL3](-) (PPN = bis(triphenylphosphoranylidene) ammonium and L = diphenylphosphinobenzenethiolate) are known to undergo addition reactions with unsaturated hydrocarbons via the formation of new C-S bonds in solution upon oxidation. The reaction mechanism is proposed to involve metal-stabilized thiyl radical intermediates, a new type of distonic ions such as [RuL3](+) ion in the case of [PPN](+)[RuL3](-). This study presents the reactivity and structure investigation of [RuL3](+) by mass spectrometry (MS) in conjunction with ion/molecule reactions. The addition reactions of [RuL3](+) with alkenes or methyl ketones in the gas phase are indeed observed, in agreement with the proposed mechanism. Such reactivity is also maintained by several fragment ions of [RuL3](+), indicating the preserved thiyl diradical core structure is responsible for the addition reaction. The thiyl radical nature of [RuL3](+) was further verified by the ion/molecule reaction of [RuL3](+) with dimethyl disulfide, in which the characteristic CH3S• transfer occurs, both at atmospheric pressure and also at low pressure (~mTorr). These results provide, for the first time, clear mass spectrometric evidence of the radical nature of [RuL3](+) (i.e., the distonic ion structure of [RuL3](+)), arising from the oxidation of non-innocent thiolate ligands of the complex [PPN](+)[RuL3](-). Similar thiolate complexes, including ReL3 and NiL2, were also examined. Although reactions of oxidized ReL3 or NiL2 with CH3SSCH3 take place at atmospheric pressure, the corresponding reaction did not occur in vacuum. Consistent with these data, the addition of ethylene was not observed either, indicating lower reactivities of [ReL3](+) and [NiL2](+) in comparison to [RuL3](+).