Direct and Indirect Chimeric Antigen Receptor T-Cell Imaging with PET/MRI in a Tumor Xenograft Model.

Background Chimeric antigen receptor (CAR) T cells are a promising cancer therapy; however, reliable and repeatable methods for tracking and monitoring CAR T cells in vivo remain underexplored. Purpose To investigate direct and indirect imaging strategies for tracking the biodistribution of CAR T cells and monitoring their therapeutic effect in target tumors. Materials and Methods CAR T cells co-expressing a tumor-targeting gene (anti-CD19 CAR) and a human somatostatin receptor subtype 2 (hSSTr2) reporter gene were generated from human peripheral blood mononuclear cells. After direct labeling with zirconium 89 (89Zr)-p-isothiocyanatobenzyl-desferrioxamine (DFO), CAR T cells were intravenously injected into immunodeficient mice with a CD19-positive and CD19-negative human tumor xenograft on the left and right flank, respectively. PET/MRI was used for direct in vivo imaging of 89Zr-DFO-labeled CAR T cells on days 0, 1, 3, and 7 and for indirect cell imaging with the radiolabeled somatostatin receptor-targeted ligand gallium 68 (68Ga)-DOTA-Tyr3-octreotide (DOTATOC) on days 6, 9, and 13. On day 13, mice were euthanized, and tissues and tumors were excised. Results The 89Zr-DFO-labeled CAR T cells were observed on PET/MRI scans in the liver and lungs of mice (n = 4) at all time points assessed. However, they were not visualized in CD19-positive or CD19-negative tumors, even on day 7. Serial 68Ga-DOTATOC PET/MRI showed CAR T cell accumulation in CD19-positive tumors but not in CD19-negative tumors from days 6 to 13. Notably, 68Ga-DOTATOC accumulation in CD19-positive tumors was highest on day 9 (mean percentage injected dose [%ID], 3.7% ± 1.0 [SD]) and decreased on day 13 (mean %ID, 2.6% ± 0.7) in parallel with a decrease in tumor volume (day 9: mean, 195 mm3 ± 27; day 13: mean, 127 mm3 ± 43) in the group with tumor growth inhibition. Enhanced immunohistochemistry staining of cluster of differentiation 3 (CD3) and hSSTr2 was also observed in excised CD19-positive tumor tissues. Conclusion Direct and indirect cell imaging with PET/MRI enabled in vivo tracking and monitoring of CAR T cells in an animal model. © RSNA, 2024 Supplemental material is available for this article. See also the editorial by Bulte in this issue.

Cancer Prediction With Machine Learning of Thrombi From Thrombectomy in Stroke: Multicenter Development and Validation.

BACKGROUND: We aimed to develop and validate machine learning models to diagnose patients with ischemic stroke with cancer through the analysis of histopathologic images of thrombi obtained during endovascular thrombectomy. METHODS: This was a retrospective study using a prospective multicenter registry which enrolled consecutive patients with acute ischemic stroke from South Korea who underwent endovascular thrombectomy. This study included patients admitted between July 1, 2017 and December 31, 2021 from 6 academic university hospitals. Whole-slide scanning was performed for immunohistochemically stained thrombi. Machine learning models were developed using transfer learning with image slices as input to classify patients into 2 groups: cancer group or other determined cause group. The models were developed and internally validated using thrombi from patients of the primary center, and external validation was conducted in 5 centers. The model was also applied to patients with hidden cancer who were diagnosed with cancer within 1 month of their index stroke. RESULTS: The study included 70 561 images from 182 patients in both internal and external datasets (119 patients in internal and 63 in external). Machine learning models were developed for each immunohistochemical staining using antibodies against platelets, fibrin, and erythrocytes. The platelet model demonstrated consistently high accuracy in classifying patients with cancer, with area under the receiver operating characteristic curve of 0.986 (95% CI, 0.983-0.989) during training, 0.954 (95% CI, 0.937-0.972) during internal validation, and 0.949 (95% CI, 0.891-1.000) during external validation. When applied to patients with occult cancer, the model accurately predicted the presence of cancer with high probabilities ranging from 88.5% to 99.2%. CONCLUSIONS: Machine learning models may be used for prediction of cancer as the underlying cause or detection of occult cancer, using platelet-stained immunohistochemical slide images of thrombi obtained during endovascular thrombectomy.

Smart Vitamin Micelles as Cancer Nanomedicines for Enhanced Intracellular Delivery of Doxorubicin.

Chemotherapy is one of the most effective treatments for cancer. However, intracellular delivery of many anticancer drugs is hindered by their hydrophobicity and low molecular weight. Here, we describe highly biocompatible and biodegradable amphiphilic vitamin conjugates comprising hydrophobic vitamin E and hydrophilic vitamin B labeled with dual pH and glutathione-responsive degradable linkages. Vitamin-based micelles (vitamicelles), formed by self-assembly in aqueous solutions, were optimized based on their stability after encapsulation of doxorubicin (DOX). The resulting vitamicelles have great potential as vehicles for anticancer drugs because they show excellent biocompatibility (>94% after 48 h of incubation) and rapid biodegradability (>90% after 2.5 h). Compared with free DOX, DOX-loaded vitamicelles showed a markedly enhanced anticancer effect as they released the drug rapidly and inhibited drug efflux out of cells efficiently. By exploiting these advantages, this study not only provides a promising strategy for circumventing existing challenges regarding the delivery of anticancer drugs but also extends the utility of current DOX-induced chemotherapy.

Diagnostic accuracy and safety of 16α-[18F]fluoro-17ß-oestradiol PET-CT for the assessment of oestrogen receptor status in recurrent or metastatic lesions in patients with breast cancer: a prospective cohort study.

BACKGROUND: A biopsy of first recurrence or metastatic disease is recommended to re-evaluate oestrogen receptor status in patients with breast cancer and to select appropriate treatment. However, retesting for oestrogen receptor status with rebiopsy is not always feasible, depending on lesion location and the risk associated with biopsy, and in these cases clinicians continue to treat patients according to the oestrogen receptor status of the primary tumour. Consequently suboptimal therapy might be offered to these patients. We assessed the diagnostic accuracy and safety of 16α-[18F]fluoro-17ß-oestradiol (18F-FES) PET-CT to assess oestrogen receptor status in patients with recurrent or metastatic breast cancer. METHODS: We did a prospective cohort study at the Asan Medical Center, Seoul, South Korea. Eligible patients had breast cancer, with first recurrence or metastatic disease at presentation, were 19 years or older, and had an Eastern Cooperative Oncology Group performance status of 0-2. The primary objective was to show the agreement between qualitative 18F-FES PET-CT interpretation and the results of oestrogen receptor expression by immunohistochemical assay, a non-reference standard test. Whole-body 18F-FES PET-CT imaging was done after intravenous injection of 111-222 MBq of 18F-FES, with dosing primarily determined by radiation dosimetry analysis. 18F-FES uptake above background intensity was interpreted as positive. Efficacy was assessed in all patients with histologically confirmed recurrent or metastatic breast cancer who received 18F-FES and had PET-CT images available (intention-to-diagnose analysis), and safety was assessed in all patients who received 18F-FES. This study is registered with ClinicalTrials.gov, number NCT01986569. FINDINGS: Between Nov 27, 2013, and Nov 10, 2016, 93 patients were enrolled. Of the 85 patients included in the efficacy analysis, 47 (55%) were oestrogen receptor-positive and 38 (45%) were oestrogen receptor-negative. Positive status percent agreement between the 18F-FES PET-CT results and oestrogen receptor status by immunohistochemical assay was 76·6% (95% CI 62·0-87·7) and the negative status percent agreement was 100·0% (90·8-100·0). Patients who were oestrogen receptor-positive and had a positive 18F-FES PET-CT result had a significantly higher progesterone receptor expression than those who were oestrogen receptor-positive and had a negative 18F-FES PET-CT result (23 [68%] of 34 patients vs 0 of 11 patients; p<0·0001). The most common adverse event was procedural pain in nine (10%) of 90 patients injected with 18F-FES. No adverse events were related to the study drug except injection site pain in one (1%) patient. No serious adverse events were recorded. INTERPRETATION: The high negative percent agreement between 18F-FES PET-CT and oestrogen receptor status by immunohistochemical assay in this cohort suggests that positive 18F-FES uptake by recurrent or metastatic oestrogen receptor-positive breast cancer lesions could be an alternative to oestrogen receptor assays in this setting. Staging assessment should include 18F-FES PET-CT when retesting oestrogen receptor status is not feasible. FUNDING: Asan Institute for Life Sciences, Ministry of Health and Welfare, South Korea.

Graphitic Hollow Nanocarbon as a Promising Conducting Agent for Solid-State Lithium Batteries.

All-solid-state batteries (ASSBs) have lately received enormous attention for electric vehicle applications because of their exceptional stability by engaging all-solidified cell components. However, there are many formidable hurdles such as low ionic conductivity, interface instability, and difficulty in the manufacturing process, for its practical use. Recently, carbon, one of the representative conducting agents, turns out to largely participate in side reactions with the solid electrolyte, which finally leads to the formation of insulating side products at the interface. Although the battery community mentioned that parasitic reactions are presumably attributed to carbon itself or the generation of electronic conducting paths lowering the kinetic barrier for reactions, the underlying origin for such reactions as well as appropriate solutions have not been provided yet. In this study, for the first time, it is verified that the functional group on carbon is an origin for causing negative effects on interfacial stability and a graphitized hollow nanocarbon as a promising solution for improving-electrochemical performance is introduced. This work offers an invaluable lesson that a relatively minor part, such as a conducting agent, in ASSBs sometimes gives more positive impact on improving electrochemical performance than huge efforts for resolving other parts.

Effect of different sizes of bioactive glass-coated mesoporous silica nanoparticles on dentinal tubule occlusion and mineralization.

OBJECTIVES: To synthesize two different sizes of bioactive glass-coated mesoporous silica nanoparticles (BGN@MSNs) and to investigate their effects on dentinal tubule occlusion and remineralization. MATERIALS AND METHODS: Two different sizes of mesoporous silica nanoparticles (MSNs) were synthesized using the Stöber method (368A, 1840A) and coated with bioactive glass nanoparticles (BGNs) using a modified quick alkali-mediated sol-gel method (368B, 1840B). Sensitive tooth disc models were prepared and divided into six groups and the following treatments were applied: group 1-no treatment, group 2-bioglass, group 3-368A, group 4-368B, group 5-1840A, and group 6-1840B. Then, five discs were selected from each group and soaked in 6 wt% citric acid to test acid resistance. Dentinal tubule occlusion and occlusion ratio were observed using field-emission scanning electron microscopy. In vitro mineralization tests using simulated body fluid solution were performed to evaluate the remineralization effect of the treatment. RESULTS: All samples effectively occluded the dentinal tubule and formed a membrane-like layer. After acid treatment, 1840B (group 6) exhibited the highest rate of dentinal tubule occlusion. Remineralization was observed in 368B and 1840B, and 1840B exhibited the fastest remineralization. CONCLUSIONS: Dentinal tubule remineralization induced by the BGN@MSN biocomposite can be used to stabilize long-term prognosis in dentin hypersensitivity. The 1840B induced the most efficient remineralization, and its smaller size and larger surface area were effective for remineralization. CLINICAL RELEVANCE: The BGN@MSN biocomposite with its smaller size and larger surface area was more effective for remineralization and dentinal tubule sealing.

Dentin sealing and antibacterial effects of silver-doped bioactive glass/mesoporous silica nanocomposite: an in vitro study.

OBJECTIVES: To synthesize a silver-doped bioactive glass/mesoporous silica nanoparticle (Ag-BGN@MSN), as well as to investigate its effects on dentinal tubule occlusion, microtensile bond strength (MTBS), and antibacterial activity. MATERIALS AND METHODS: Ag-BGN@MSN was synthesized using a modified "quick alkali-mediated sol-gel" method. Demineralized tooth disc models were made and divided into four groups; the following treatments were then applied: group 1-no treatment, group 2-bioglass, group 3-MSN, group 4-Ag-BGN@MSN. Next, four discs were selected from each group and soaked into 6 wt% citric acid to test acid-resistant stability. Dentinal tubule occlusion, as well as the occlusion ratio, was observed using field-emission scanning electron microscopy. The MTBS was also measured to evaluate the desensitizing effect of the treatments. Cytotoxicity was examined using the MTT assay. Antibacterial activity was detected against Lactobacillus casei, and ion dissolution was evaluated using inductively coupled plasma optical emission spectrometry. RESULTS: Ag-BGN@MSN effectively occluded the dentinal tubule and formed a membrane-like layer. After the acid challenge, Ag-BGN@MSN had the highest rate of dentinal tubule occlusion. There were no significant differences in MTBS among the four groups (P > 0.05). All concentrations of Ag-BGN@MSN used had a relative cell viability above 72%. CONCLUSIONS: Ag-BGN@MSN was successfully fabricated using a modified sol-gel method. The Ag-BGN@MSN biocomposite effectively occluded dentinal with acid-resistant stability, did not decrease bond strength in self-etch adhesive system, had low cytotoxicity, and antibacterial effect. CLININAL RELEVANCE: Dentinal tubule sealing induced by Ag-BGN@MSN biocomposite with antibacterial effect is likely to increase long-term stability in DH.

In-Vitro Mechanical Performance Study of Biodegradable Polylactic Acid/Hydroxyapatite Nanocomposites for Fixation Medical Devices.

Osteoconductive, biocompatible, and resorbable organic/inorganic composites are most commonly used in fixation medical devices, such as suture anchors and interference screws, because of their unique physical and chemical properties. Generally, studies on biodegradable composites have focused on their mechanical properties based on the composition and the individual roles of organic and inorganic biomaterials. In this study, we prepared biodegradable organic/inorganic nanocomposite materials using the solvent mixing process and conventional molding. We used polylactic acid (PLA) as the matrix and nano-sized hydroxyapatite (nano-HAp) as the osteoconductive filler. The content of nano-HAp was varied in 0-30 wt% and its influence on the In-Vitro mechanical performance of PLA/HAp nanocomposites was evaluated. The In-Vitro mechanical properties of nanocomposites were evaluated using standardized tensile and flexural tests after different immersion times in simulated body fluid.

Polylactic Acid/Nanostructured Si-Substituted ß-Tricalcium Phosphate Composites for Biodegradable Fixation Medical Devices.

Organic/inorganic biocomposite materials for biodegradable fixation medical devices require osteoconductivity, biocompatibility, and adequate mechanical properties with biodegradation behavior. The objective of this study was to investigate the effect of Si ions substituted in ß-tricalcium phosphate (ß-TCP) on the mechanical properties of organic/inorganic biocomposites. Biodegradable composite materials were prepared with polylactic acid (PLA) as the matrix and nano Si-substituted ß-TCP as the osteoconductive filler by solvent mixing and conventional molding. The nanostructured Si-substituted ß-TCP powders were synthesized by co-precipitation, controlling the quantity of Si ions. The amount of nanostructured Si-substituted ß-TCP powders in composites was varied in the 0-40 wt% range and the material properties were compared with those of pure ß-TCP/PLA composites. The influence of Si ions on the mechanical properties of the composites was evaluated by tensile and flexural tests.

The Inhibitory Effect of Tartary Buckwheat Extracts on Adipogenesis and Inflammatory Response.

Tartary buckwheat (Fagopyrum tataricum) has been established globally as a nutritionally important food item, particularly owing to high levels of bioactive compounds such as rutin. This study investigated the effect of tartary buckwheat extracts (TBEs) on adipogenesis and inflammatory response in 3T3-L1 cells. TBEs inhibited lipid accumulation, triglyceride content, and glycerol-3-phosphate dehydrogenase (GPDH) activity during adipocyte differentiation of 3T3 L1 cells. The mRNA levels of genes involved in fatty acid synthesis, such as peroxisome proliferator-activated receptor-γ (PPAR-γ), CCAAT/enhancer binding protein-α (CEBP-α), adipocyte protein 2 (aP2), acetyl-CoA carboxylase (ACC), fatty acid synthase (FAS), and stearoylcoenzyme A desaturase-1 (SCD-1), were suppressed by TBEs. They also reduced the mRNA levels of inflammatory mediators such as tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), monocyte chemoattractant protein 1 (MCP-1), and inducible nitric oxide synthase (iNOS). In addition, TBEs were decreased nitric oxide (NO) production. These results suggest that TBEs may inhibit adipogenesis and inflammatory response; therefore, they seem to be beneficial as a food ingredient to prevent obesity-associated inflammation.

Cancer Stem Cells Protect Non-Stem Cells From Anoikis: Bystander Effects.

Cancer stem cells (CSCs) are capable of initiation and metastasis of tumors. Therefore, understanding the biology of CSCs and the interaction between CSCs and their counterpart non-stem cells is crucial for developing a novel cancer therapy. We used CSC-like and non-stem breast cancer MDA-MB-231 and MDA-MB-453 cells to investigate mammosphere formation. We investigated the role of the epithelial cadherin (E-cadherin)-extracellular signal-regulated kinase (Erk) axis in anoikis. Data from E-cadherin small hairpin RNA assay and mitogen-activated protein kinase kinase (MEK) inhibitor study show that activation of Erk, but not modulation of E-cadherin level, may play an important role in anoikis resistance. Next, the two cell subtypes were mixed and the interaction between them during mammosphere culture and xenograft tumor formation was investigated. Unlike CSC-like cells, increased secretion of interleukin-6 (IL-6) and growth-related oncogene (Gro) chemokines was detected during mammosphere culture in non-stem cells. Similar results were observed in mixed cells. Interestingly, CSC-like cells protected non-stem cells from anoikis and promoted tumor growth. Our results suggest bystander effects between CSC-like cells and non-stem cells. J. Cell. Biochem. 117: 2289-2301, 2016. © 2016 Wiley Periodicals, Inc.

Influence of Starting Powders on Hydroxyapatite Coatings Fabricated by Room Temperature Spraying Method.

Three types of raw materials were used for the fabrication of hydroxyapatite coatings by using the room temperature spraying method and their influence on the microstructure and in vitro characteristics were investigated. Starting hydroxyapatite powders for coatings on titanium substrate were prepared by a heat treatment at 1100 °C for 2 h of bovine bone, bone ash, and commercial hydroxyapatite powders. The phase compositions and Ca/P ratios of the three hydroxyapatite coatings were similar to those of the raw materials without decomposition or formation of a new phase. All hydroxyapatite coatings showed a honeycomb structure, but their surface microstructures revealed different features in regards to surface morphology and roughness, based on the staring materials. All coatings consisted of nano-sized grains and had dense microstructure. Inferred from in vitro experiments in pure water, all coatings have a good dissolution-resistance and biostability in water.

The Role of Magnesium Ion Substituted Biphasic Calcium Phosphate Spherical Micro-Scaffolds in Osteogenic Differentiation of Human Adipose Tissue-Derived Mesenchymal Stem Cells.

This study was investigated the role of magnesium (Mg2+) ion substituted biphasic calcium phosphate (Mg-BCP) spherical micro-scaffolds in osteogenic differentiation of human adipose tissue-derived mesenchymal stem cells (hAT-MSCs). Mg-BCP micro-scaffolds with spherical morphology were successfully prepared using in situ co-precipitation and spray drying atomization process. The in vitro cell proliferation and differentiation of hAT-MSCs were determined up to day 14. After in vitro biological tests, Mg-BCP micro-scaffolds with hAT-MSCs showed more enhanced osteogenicity than pure hAT-MSCs as control group by unique biodegradation of TCP phase and influence of substituted Mg2+ ion in biphasic nanostructure. Therefore, these results suggest that Mg-BCP micro-scaffolds promote osteogenic differentiation of hAT-MSCs.

Role of Bcl-xL/Beclin-1 in synergistic apoptotic effects of secretory TRAIL-armed adenovirus in combination with mitomycin C and hyperthermia on colon cancer cells.

In this study, we attempted to develop a multimodality approach using chemotherapeutic agent mitomycin C, biologic agent tumor necrosis factor-related apoptosis-inducing ligand (TRAIL/Apo-2L), and mild hyperthermia to treat colon cancer. For this study, human colon cancer LS174T, LS180, HCT116 and CX-1 cells were infected with secretory TRAIL-armed adenovirus (Ad.TRAIL) and treated with chemotherapeutic agent mitomycin C and hyperthermia. The combinatorial treatment caused a synergistic induction of apoptosis which was mediated through an increase in caspase activation. The combinational treatment promoted the JNK-Bcl-xL-Bak pathway which transmitted the synergistic effect through the mitochondria-dependent apoptotic pathway. JNK signaling led to Bcl-xL phosphorylation at serine 62, dissociation of Bak from Bcl-xL, oligomerization of Bak, alteration of mitochondrial membrane potential, and subsequent cytochrome c release. Overexpression of dominant-negative mutant of Bcl-xL (S62A), but not dominant-positive mutant of Bcl-xL (S62D), suppressed the synergistic death effect. Interestingly, Beclin-1 was dissociated from Bcl-xL and overexpression of dominant-negative mutant of Bcl-xL (S62A), but not dominant-positive mutant of Bcl-xL (S62D), suppressed dissociation of Beclin-1 from Bcl-xL. A combinatorial treatment of mitomycin C, Ad.TRAIL and hyperthermia induced Beclin-1 cleavage, but the Beclin-1 cleavage was abolished in Beclin-1 double mutant (D133A/D146A) knock-in HCT116 cells, suppressing the apoptosis induced by the combination therapy. We believe that this study supports the application of the multimodality approach to colon cancer therapy.

Thymidine phosphorylase influences [(18)F]fluorothymidine uptake in cancer cells and patients with non-small cell lung cancer.

PURPOSE: Thymidine phosphorylase (TP), a key enzyme in the pyrimidine nucleoside salvage pathway, catalyses the reversible phosphorylation of thymidine, thereby generating thymine and 2-deoxy-D-ribose-1-phosphate. By regulating the levels of endogenous thymidine, TP may influence [(18)F]fluorothymidine ([(18)F]FLT) uptake. We investigated the effect of TP activity on [(18)F]FLT uptake by tumours. METHODS: Uptake of [(3)H]FLT and [(3)H]thymidine ([(3)H]Thd) and the activities of TP, thymidine kinase 1 (TK1), and equilibrative nucleoside transporter 1 (ENT1) were determined in exponentially growing A431, A549, HT29, HOP92, ACHN, and SKOV3 cells in the presence or absence of tipiracil hydrochloride, a TP inhibitor. Eighty-five non-small cell lung cancer tissues from a patient cohort that was previously studied with [(18)F]FLT positron emission tomography (PET) were retrieved and subjected to immunohistochemical analysis of TP expression. Factors that affected the maximum standardised uptake value (SUVmax) of [(18)F]FLT-PET were identified by multiple linear regression analysis. RESULTS: A431 cells had the highest TP activity; A549 and HT29 cells had moderate TP activity; and ACHN, SKOV3, and HOP92 cells had little detectable TP activity. Cell lines with high TP activity took up more [(3)H]FLT than [(3)H]Thd, whereas cells with little TP activity took up more [(3)H]Thd than [(3)H]FLT. In cells with high TP activity, TP inhibition decreased [(3)H]FLT uptake and increased [(3)H]Thd uptake. However, TP inhibition had no effect on ACHN, SKOV3, and HOP92 cells. TP inhibition did not change TK1 or ENT1 activity, but did increase the intracellular level of thymidine. The SUVmax of [(18)F]FLT was affected by three independent factors: Ki-67 expression (P < 0.001), immunohistochemical TP score (P < 0.001), and tumour size (P = 0.015). CONCLUSIONS: TP activity influences [(18)F]FLT uptake, and may explain preferential uptake of [(18)F]FLT over [(3)H]Thd. These results provide important insights into the biology of [(18)F]FLT as a proliferation marker.

Emission Directionality of 3D-Printed Photonic Nanowires.

Photonic devices can be advanced by increasing the density of the integrated optical components. As the integration density increases, the potential for signal interference between adjacent components, optical crosstalk, becomes a concern. To address the crosstalk issue, it is crucial to identify the emission directionality of the integrated optical components. In this study, we investigate the emission directionality of 3D printed light-emitting nano/microwires. We experimentally and numerically showed that when the diameter is reduced below the single-mode cutoff, the emission becomes noticeably directional. In addition, our demonstrations on pairs of closely positioned wires show that optical crosstalk can be effectively avoided by reducing the diameter to the nanoscale to exploit the strong directionality of its emission. We expect that our study can be applied to various fundamental research and applications in the fields of photonics, optical communication, sensing, and imaging, where the directionality of the emissions is crucial.

Synthesis, Characterization, and Biological Performances of Magnesium-Substituted Dicalcium Phosphate Anhydrous.

Dicalcium phosphate anhydrous (DCPA, CaHPO4) is regarded as an orthopedic material due to its ability to match the generation of new bone to the rate of implant resorption without considering the material's mechanical stability. Additionally, magnesium (Mg) is widely recognized for its essential function in bone metabolism, especially during the initial phases of osteogenesis. Therefore, we explored the influences of Mg ions on DCPA powder, in biological responses, and on the enhancement of osteogenic properties. Mg-DCPA powders with varying substitution levels (0, 3, 5, and 7 mol%) were produced using the co-precipitation method. In the in vitro test, precipitates began to develop on the surface of the Mg-DCPA powders after 7 days. These results indicate that Mg ions in the DCPA powder could enhance the generation of a new apatite phase when subjected to physiological fluids on the surface of the powder. In addition, the osteogenic performance of the DCPA powder was improved by adding Mg ions. The most effective magnesium substitution content in the DCPA powder in order to improve its osteogenic potential was approximately 3 mol%. Consequently, this amount of magnesium in the DCPA powder could control the maintaining time in the implantation operation to produce a new apatite phase.

Long-term hybrid stability and matrix metalloproteinase inhibition by fucosterol in resin-dentin bonding biomechanics.

Fucosterols have been widely studied for their antioxidant, anticancer, and anti-inflammatory properties. However, they have not yet been studied in the field of dentistry. This study aimed to determine whether pretreatment of dentin with fucosterol before resin restoration enhances bond stability in resin-dentin hybrid layers. After applying 0.1, 0.5, and 1.0 wt% fucosterol to demineralized dentin, microtensile bond strength (MTBS) and nanoleakage tests were performed before and after collagenase aging, and the surface was observed using scanning electron microscope (SEM). The fucosterol-treated group showed better bond strength and less nanoleakage both before and after collagenase aging, and the corresponding structures were confirmed using SEM. MMP zymography confirmed that the activity of MMPs was relatively low along the concentration gradient of fucosterol, and the FTIR analysis confirmed the production of collagen crosslinks. In addition, fucosterol exhibits cytotoxicity against Streptococcus mutans, the main cause of dental decay. The results of this study suggest that fucosterol pretreatment improves bond strength and reduces nanoleakage at the resin-dentin interface, possibly through a mechanism involving collagen cross-link formation via the inhibition of endogenous and exogenous MMP activity. This study demonstrates the potential of fucosterol as an MMP inhibitor in dentin, which contributes to long-term resin-dentin bond stability and can be used as a restorative material.

18F-ASEM PET/MRI targeting alpha7-nicotinic acetylcholine receptor can reveal skeletal muscle denervation.

BACKGROUND: The increased expression of the nicotinic acetylcholine receptor (nAChR) in muscle denervation is thought to be associated with electrophysiological acetylcholine supersensitivity after nerve injury. Hence, we investigated the utility of the 18F-ASEM alpha7-nAChR targeting radiotracer as a new diagnostic method by visualizing skeletal muscle denervation in mouse models of sciatic nerve injury. METHODS: Ten-week-old C57BL/6 male mice were utilized. The mice were anesthetized, and the left sciatic nerve was resected after splitting the gluteal muscle. One week (n = 11) and three weeks (n = 6) after the denervation, 18F-ASEM positron emission tomography/magnetic resonance imaging (PET/MRI) was acquired. Maximum standardized uptake values (SUVmax) of the tibialis anterior muscle were measured for the denervated side and the control side. Autoradiographic evaluation was performed to measure the mean counts of the denervated and control tibialis anterior muscles at one week. In addition, immunohistochemistry was used to identify alpha7-nAChR-positive areas in denervated and control tibialis anterior muscles at one week (n = 6). Furthermore, a blocking study was conducted with methyllycaconitine (MLA, n = 5). RESULTS: 18F-ASEM PET/MRI showed significantly increased 18F-ASEM uptake in the denervated tibialis anterior muscle relative to the control side one week and three weeks post-denervation. SUVmax of the denervated muscles at one week and three weeks showed significantly higher uptake than the control (P = 0.0033 and 0.0277, respectively). The relative uptake by autoradiography for the denervated muscle was significantly higher than in the control, and immunohistochemistry revealed significantly greater alpha7-nAChR expression in the denervated muscle (P = 0.0277). In addition, the blocking study showed no significant 18F-ASEM uptake in the denervated side when compared to the control (P = 0.0796). CONCLUSIONS: Our results suggest that nAChR imaging with 18F-ASEM has potential as a noninvasive diagnostic method for peripheral nervous system disorders.