Effect of pH on the chelation between strontium ions and decellularized small intestinal submucosal sponge scaffolds / 北京大学学报(医学版)

OBJECTIVE@#To investigate the preparation of decellularized small intestinal submucosa (dSIS) sponge scaffolds with chelated strontium (Sr) ions at different pH values, and to select the appropriate pH values for synthesizing Sr/dSIS scaffolds using the physicochemical properties and biocompatibility of the scaffolds as evaluation indexes.@*METHODS@#(1) Sr/dSIS scaffolds preparation and grouping: After mixing dSIS solution and strontium chloride solution in equal volumes, adjusting pH of the solution to 3, 5, 7, and 9 respectively, porous scaffolds were prepared by freeze-drying method after full reaction at 37℃, which were named Sr/dSIS-3, -5, -7, and -9 respectively, and the dSIS scaffolds were used as the control group. (2) Physicochemical property evaluation: The bulk morphology of the scaffolds was observed in each group, the microscopic morphology analyzed by scanning electron microscopy, and the porosity and pore size determined, the surface elements analyzed by energy spectroscopy, the structure of functional groups analyzed by infrared spectroscopy, the chelation rate determined by atomic spectrophotometry, the water absorption rate detected by using specific gravity method, and the compression strength evaluated by universal mechanical testing machine.(3) Biocompatibility evaluation: The cytotoxicity and proliferative effect to bone mesenchymal stem cells (BMSCs) of each group were evaluated by Calcein-AM/PI double staining method.@*RESULTS@#Scanning electron microscopy showed that the scaffolds of each group had an interconnected three-dimensional porous structure with no statistical difference in pore size and porosity. Energy spectrum analysis showed that strontium could be detected in Sr/dSIS-5, -7 and -9 groups, and strontium was uniformly distributed in the scaffolds. Functional group analysis further supported the formation of chelates in the Sr/dSIS-5, -7 and -9 groups. Chelation rate analysis showed that the Sr/dSIS-7 group had the highest strontium chelation rate, which was statistically different from the other groups (P < 0.05). The scaffolds in all the groups had good water absorption. The scaffolds in Sr/dSIS-5, -7 and -9 groups showed significantly improved mechanical properties compared with the control group (P < 0.05). The scaffolds in all the groups had good biocompatibility, and the Sr/dSIS-7 group showed the best proliferation of BMSCs.@*CONCLUSION@#When pH was 7, the Sr/dSIS scaffolds showed the highest strontium chelation rate and the best proliferation effect of BMSCs, which was the ideal pH value for the preparation of the Sr/dSIS scaffolds.

Antiarrhythmic active components in traditional Chinese medicine acting on potassium channels / 中国中药杂志

Arrhythmia is an external manifestation of cardiac electrophysiological disorder. It exists in healthy people and patients with various heart diseases, which is often associated with other cardiovascular diseases. The contraction and diastole of myocardium are inseparable from the movement of ions. There are many ion channels in the membrane and organelle membrane of myocardium. The dynamic balance of myocardial ions is vital in maintaining myocardial electrical homeostasis. Potassium ion channels that have a complex variety and a wide distribution are involved in the whole process of resting potential and action potential of cardiomyocytes. Potassium ion channels play a vital role in maintaining normal electrophysiological activity of myocardium and is one of the pathogenesis of arrhythmia. Traditional Chinese medicine(TCM)has unique advantages in treating arrhythmia for its complex active components and diverse targets. A large number of TCM preparations have definite effect on treating arrhythmia-related diseases, whose antiarrhythmic mechanism may be related to the effect on potassium channel. This article mainly reviewed the relevant studies on the active components in TCM acting on different potassium channels to provide references for clinical drug use and development.

Study on fragmentation patterns of coumarins in Notopterygium inchum with ultrahigh performance liquid chromatography combined with quadrupole time-of-flight mass spectrometry / 中国中药杂志

To demonstrate the fragmentation patterns of simple coumarins furanocourmarin(C_7-C_8), furanocourmarin(C_6-C_7) and dihydrofuran coumarin by mass spectrometry, with fraxin, scopoletin, isopsoralen, pimpinellin, isoimperatorin, notopterol and noda-kenin as study subjects, so as to provide a basis for rapid identification of compounds in different subtypes of coumarins. Ultrahigh performance liquid chromatography combined with quardrupole time-of-flight mass spectrometry(UPLC-Q-TOF-MS) was implemented in both positive and negative ion modes. Masslynx software was employed to provide the elemental constituents of each detected ion based on its accurate molecular weight. Chemdraw 2014 was used to cultivate mass number of each inferred structure. The fragment pattern of each compound was determined based on the structures inferred from all the relevant ions. And the patterns were drawn by Chemdraw 2014. The deviation between the calculated molecular weight of the inferred structure and the detected value of the ions was used to assess the correctness of the inferred structures in the fragmentation patterns. The results showed that with UPLC-Q-TOF, neutral loss of CO_2 and CO was reflected in lactone and furan skeletons from the courmarin structure. An even mass was attributed to the loss of an odd number of methyl radicals from compounds with a methoxy substituent. Furanocourmarin(C_7-C_8) produced a protonated molecular ion([M+H]~+), while the other courmarin subtypes produced either a sodium adduct of the molecular ion([M+Na]~+) or a sodium adduct of the molecular ion([M+Na]~+) with a protonated molecular ion([M+H]~+). The m/z 203.03 was a diagnostic ion for furanocourmarin(C_6-C_7), and the m/z 147.04 was supplementary evidence for furanocourmarin(C_6-C_7) identification. The characteristic ion of furanocourmarin(C_7-C_8) was m/z 131.05, while m/z 187.04 was the characteristic ion of dihydrofuran coumarin. The m/z 203.03 ion for furanocourmarin(C_7-C_8) was pretty weak. In negative ion mode, furanocourmarin(C_7-C_8) did not have any signals that were different from the other subtypes of courmarins. The fragmentation patterns in negative ion mode for the other subtypes of courmarins were similar to those in positive ion mode. Four types of fragmentation patterns were identified as forcourmarins from Notopterygium inchum. This study provides the basis for the rapid identification of courmarin subtypes by mass spectrometry.

The effect of parasitic ions on riboflavin permeability and cross-linking effectiveness in iontophoresis-assisted scleral cross-linking / 生物医学工程学杂志

The effect of parasitic ions on the results of ultraviolet A (UVA) cross-linking in iontophoresis was still not clear. In this work, the porcine sclera was cross-linked by riboflavin lactate Ringer's solution (group A) and riboflavin normal saline (group B)

Advances in anti-adversity of biological composites based on metal-organic frameworks / 生物工程学报

Metal-organic frameworks (MOFs) are formed by self-assembly of metal ions or clusters with organic ligands, and are widely used in the fields of catalysis, sensing, energy and biomedicine. Recently, biological composites based on MOFs have attracted increasing attention. MOFs can be used as a platform for encapsulating bioactive substances due to the advantages such as large pore capacity, large specific surface area and diverse structure composition. These features can protect bioactive substances from adverse conditions, e.g. high temperature, high pressure, and organic solvents, thus improving the anti-adversity of bioactive substances. This review summarizes the advances of using MOFs as protective coatings to improve the anti-adversity of different bioactive substances, and introduces the synthesis strategy of MOFs-based biological composites, with the aim to promote the practical application of MOFs-based biological composites.

Determination of Salt Forms of New Psychoactive Substances by Ion Chromatography / 法医学杂志

Objective To establish an ion chromatography method for the salt form determination of new psychoactive substances （NPS）. Methods The method of conducting qualitative and quantitative analysis of six types of organic acid ions （acetate ion, tartrate ion, maleate ion, oxalate ion, fumarate ion, citrate ion） and five types of inorganic anions （fluoride ion, chloride ion, nitrate ion, sulfate ion, phosphate ion） in NPS sample by ion chromatography was developed. The salt forms of 222 seized NPS samples （103 samples with synthetic cannabinoids, 81 samples with cathinones, 44 samples with phenylethylamines, 12 samples with tryptamines, 7 samples with phencyclidines, 6 samples with piperazines, 2 samples with aminoindenes, 26 samples with fentanyls and 43 samples with other types of NPS） were analyzed by this method. Results Each anion had good linearity in the corresponding linear range, the correlation coefficients （r） were greater than 0.999, the limits of detection were 0.01-0.05 mg/L, and the limits of quantitative were 0.1-0.5 mg/L. Except that 5F-BEPIRAPIM was hydrochloride, the salt forms of the other 102 synthetic cannabinoids were all base. The salt form of 81 cathinone samples, 44 phenylethylamine samples, 7 phencyclidine samples and 2 aminoindene samples were all hydrochloride. The salt forms of tryptamine samples included base, hydrochloride, fumarate and oxalate. The salt forms of piperazine samples included base and hydrochloride. The salt forms of fentanyl samples and samples of other types included base, hydrochloride and citrate. Conclusion Ion chromatography is a simple, accurate and efficient method for determining the salt form of NPS samples, which makes the qualitative and quantitative conclusions of NPS more scientific and rigorous.

Determination of Azide Ions in Blood by Pentafluorobenzyl Derivation Followed by GC-MS / 法医学杂志

Objective To establish a method for determination of the azide ions in blood by gas chromatography-mass spectrometry （GC-MS） following pentafluorobenzyl derivatization. Methods A blood sample of 0.2 mL was placed into a 10 mL glass test tube, and the internal standard sodium cyanide, derivatization reagent pentafluorobenzyl bromide and catalyst tetradecyl benzyl dimethyl ammonium chloride were added in turn. After vortex mixing, the mixture was heated with low-power microwave for 3 min. After centrifugation, the organic phase was taken for GC-MS analysis. Results The azide ions in blood had a good linear relationship in the mass concentration range of 0.5 to 20 μg/mL. The lowest detection limit was 0.25 μg/mL and the relative recovery was 91.36%-94.58%. The method was successfully applied to a case of death from sodium azide poisoning. The mass concentration of azide ions in the blood of the dead was 11.11 μg/mL. Conclusion The method developed in this paper has strong specificity and is easy to operate, which is suitable for the rapid detection of azide ions in blood.

DNA damage in a solution containing copper(II) ions and ascorbic acid: Effect of the presence of sulfite

Some antioxidant compounds have a pro-oxidant effect in the presence of transition metal ions, due to the reduction of Mn+ to M(n-1)+ with simultaneous formation of free radicals, which then promote DNA damage. In the present study, we evaluated the pUC19 DNA damage in a solution containing Cu(II) and ascorbic acid (AA) or S(IV) saturated with air by agarose gel electrophoresis. Our results showed that this damage decreases if AA and S(IV) are simultaneously added. This study also illustrates the importance of Cu(II) in this process, as no DNA damage was observed when AA or S(IV) were present in the absence of this metallic ion. Our data showed that DNA preservation depends on the concentration of AA and S(IV) and occurs when the [S(IV)]:[AA] ratio ranges from 1:1 to 20:1. Absorbance measurements and thermodynamic data show that no reaction occurs between AA and S(IV) when this mixture (pH 5.5) is added to pUC-19 DNA. The presence of dissolved oxygen may be the cause of AA consumption in the mixture of these two antioxidants, which subsequently decreases DNA damage.

Effects of SCD-1 gene overexpression on the content of calcium ion and lipids in duck uterine epithelial cells / 生物工程学报

Stearoyl-CoAdesaturase-1 (SCD-1) is a key regulator of monounsaturated fatty acid synthesis. It plays a vital role in lipid synthesis and metabolism. Ca²⁺ is an important cation in the body and plays an important role in the organism. The aims of this study were to investigate the correlation of SCD-1 gene overexpression with lipid indexes and calcium ion level. The pcDNA3.1 (+) + SCD-1 +Flag eukaryotic expression vector and cultured duck uterine epithelial cells were co-transfected. The overexpression of SCD-1 gene was measured using the Flag Label Detection Kit. Ca ions and lipid contents were detected through Fluo-3/AM Calcium Ion Fluorescence Labeling method and Lipid Measuring Kit, respectively. SCD-1 gene overexpression was negatively correlated with triglyceride (TG) and high-density lipoprotein cholesterol (HDL-C), and positively correlated with Ca ion, total cholesterol (TC), very low-density lipoprotein cholesterol (VLDL-C) and low density lipoprotein cholesterol (LDL-C) levels. Meanwhile, Ca ion was positively correlated with TG, LDL-C and HDL-C contents, and negatively correlated with TC and VLDL-C levels. Overexpression of SCD-1 gene could regulate Ca ion secretion, as well as lipid synthesis and transport in duck uterine epithelial cells.

Fluoxetine Induces Apoptotic and Oxidative Neuronal Death Associated with The Influx of Copper Ions in Cultured Neuronal Cells / 전남의대학술지

We examined the effect of fluoxetine, a selective serotonin reuptake inhibitor antidepressant, on neuronal viability in mouse cortical near-pure neuronal cultures. Addition of fluoxetine to the media for 24 hours induced neuronal death in a concentration-dependent manner. To delineate the mechanisms of fluoxetine-induced neuronal death, we investigated the effects of trolox, cycloheximide (CHX), BDNF, z-VAD-FMK, and various metal-chelators on fluoxetine-induced neuronal death. Neuronal death was assessed by MTT assay. The addition of 20 µM fluoxetine to the media for 24 hours induced 60–70% neuronal death, which was associated with the hallmarks of apoptosis, chromatin condensation and DNA laddering. Fluoxetine-induced death was significantly attenuated by CHX, BDNF, or z-VAD-FMK. Treatment with antioxidants, trolox and ascorbate, also markedly attenuated fluoxetine-induced death. Interestingly, some divalent cation chelators (EGTA, Ca-EDTA, and Zn-EDTA) also markedly attenuated the neurotoxicity. Fluoxetine-induced reactive oxygen species (ROS) generation was measured using the fluorescent dye 2′,7′-dichlorofluorescin diacetate. Trolox and bathocuproine disulfonic acid (BCPS), a cell membrane impermeable copper ion chelator, markedly attenuated the ROS production and neuronal death. However, deferoxamine, an iron chelator, did not affect ROS generation or neurotoxicity. We examined the changes in intracellular copper concentration using a copper-selective fluorescent dye, Phen Green FL, which is quenched by free copper ions. Fluoxetine quenched the fluorescence in neuronal cells, and the quenching effect of fluoxetine was reversed by co-treatment with BCPS, however, not by deferoxamine. These findings demonstrate that fluoxetine could induce apoptotic and oxidative neuronal death associated with an influx of copper ions.

Determinação de baixas concentrações de lítio em águas de abastecimento público por cromatografia de íons: validação de método / Determination of low concentrations of lithium in public water supply by the ion chromatography: method validation

Esta nota apresenta a validação de um método para realizar a determinação de lítio em concentrações menores do que 40 µg L­1 em amostras de águas de abastecimento público, utilizando­se cromatografia de íons e calibração externa, com a curva analítica obtida por regressão linear (mínimos quadrados ordinários). O método é seletivo, e apresenta limite de detecção igual a 1,0 µg L­1e limite de quantificação igual a 2,0 µg L­1.Os ensaios de recuperação em três níveis de concentração apresentaram resultados entre 99,4 e 101,9%. Na avaliação da precisão nos mesmos três níveis de concentração, os coeficientes de variação exibiram valores entre 1,1 e 4,0%. (AU)

This note presents the validation of a method for determining the lithium at concentrations less than 40 µg L­1 in the public water supply, by using the ion chromatography and external calibration, and the analytical curve was obtained by the linear regression (ordinary least squares). The employed method is selective, showing the detection limit equal to 1.0 µg L­1 and the quantification limit equal to 2.0 µg L­1. Recovery tests in three concentration levels presented results from 99.4 to 101.9%. On the precision evaluation in the same three concentration levels, the coefficients of variation exhibited values between 1.1 and 4.0%. (AU)

Effect of Ions Released and pH of Two Glass Ionomer Cements in Human Gingival Fibroblasts / Efecto de la liberación de iones y pH de dos cementos de ionómero de vidrio en fibroblastos gingivales humanos

Abstract 20. Conventional glass ionomer cements are used as dental provisional restorative materials, which present several advantages such as adhesion to the tooth mineral phase among others. On the other hand, the knowledge about biological property of glass ionomers shows various approaches and results. In this work, it was studied the in vitro biological response of human gingival fibroblasts in contact with commercial cements of glass ionomer: Mirafil® and Ionglass® and with their extracts, according to ISO 10993. The extracts of the cements, in which the cells were cultured, were adjusted at different concentrations ranging 0.1% to 100%. The cellular metabolic activity of gingival fibroblasts was measured using the Alamar Blue® reagent. The results showed a significant effect on the cellular metabolic activity correlated with the concentration of liberated ions (Al³+ and Ca²+) for both ionomers, as well as the pH variations of the culture media. This could mean that the cellular metabolic activity is substantially influenced by ions and pH of the cell culture.

Resumen 24. Los cementos de ionómero de vidrio convencionales se utilizan como materiales de restauración provisional para uso dental, los cuales presentan varias ventajas como la adhesión a la fase mineral de los dientes. Por otro lado, las propiedades biológicas de los ionómeros de vidrio muestran diversos enfoques y resultados. En éste trabajo se estudió la respuesta biológica in vitro de fibroblastos gingivales humanos en contacto con cementos comerciales de ionómero de vidrio: Mirafil® e Ionglass® y con sus respectivos extractos según la norma ISO 10993. Los extractos de los cementos en los que se cultivaron las células estaban en diferentes concentraciones: de 0.1% a 100%. La actividad metabólica celular se midió usando el reactivo Alamar Blue®. Los resultados mostraron un efecto significativo sobre la actividad metabólica celular correlacionada con la concentración de iones liberados (Al³+ y Ca²+) para ambos ionómeros, así como las variaciones de pH de los medios de cultivo. Ello podria explicar la influencia por los iones y el pH del cultivo celular en la actividad metabólica celular.

Nickel and Chromium Ion Levels in Hair and Gingival Crevicular Fluid with the Corrosion of Brackets in Orthodontic Patients: A Longitudinal Study

Objective: To assess the levels of nickel and chromium ions in hair and Gingival Crevicular Fluid (GCF) of orthodontic patients and to evaluate the corrosion of orthodontic bracket surfaces. Material and Methods: Nickel and chromium ion concentrations were measured in hair and GCF of 15 patients (9 females and 6 males, aged 16-28 years old) who had fixed orthodontic treatment using atomic absorption spectroscopy. The samples were taken before treatment (baseline), 4, 8, and 16 months later during treatment. Along with ionic sampling, microscopic sampling was done. One of each patient brackets was removed to get 15 brackets per group. Five brackets were taken randomly from each group to be examined under scanning electron microscope (SEM). Data obtained were analyzed using paired t-tests. Results: After 16 months, compared with the baseline, average hair nickel level changed from 0.125 µg/g to 0.956 µg/g with statistically significant difference (p=0.00); average chromium level changed from 0.090 µg/g to 0.295 µg/g but no significant difference (p>0.05); average GCF nickel level changed from 3.335 µg/g to 10.410 µg/g; average chromium level changed from 1.859 µg/g to 9.818 µg/g. Both of these increases were significant (p=0.000). SEM examinations showed that the corrosion on brackets was seen in the fourth month, and more severely visible after 8 and 16 months of uses. Conclusion: After 16 months of treatment, compared with the baseline, the hair nickel level was increased by 7.7 times; while for chromium was by 3.3 times. Gingival crevicular fluid nickel level was increased by 3.1 times and chromium level was by 5.3 times. The longer time of treatment, the more ions released and the more corrosion of brackets will be.

Follow-up of Metal-on-Metal Hip Replacements at a Large District Hospital and the Implementation of Medicines and Healthcare Products Regulatory Agency Guidelines: A Review of 297 Patients

BACKGROUND: Medicines and Healthcare products Regulatory Agency (MHRA) guidance for patients with metal-on-metal (MoM) hip replacements was provided in 2012 and updated in 2017 to assist in the early detection of soft-tissue reactions due to metal wear debris. A large number of MoM hip replacements were undertaken at our hospital trust. A program of recall for all patients with MoM hip replacements was undertaken and MHRA guidelines were implemented. In this study, we aimed to investigate the effectiveness of the revised MHRA guidelines in the detection of early adverse reactions to metal debris and to re-evaluate the indications for metal artifact reduction sequence magnetic resonance imaging (MARS-MRI) and revision surgery. METHODS: Identification and recall of all patients with MoM hip replacements from 2001 were conducted by using theatre logs, patient records, clinical coding information, and consultant logbooks. Two senior arthroplasty consultants reviewed X-rays and patient records. Postal questionnaires were forwarded to patients, together with requests for general practitioners to complete cobalt and chromium blood tests. The two consultant-led review of MOM replacements was undertaken with further radiological investigations (X-rays, MARS-MRI) performed according to the 2017 guidance with support of consultant radiologists. RESULTS: Of 674 identified patients, 297 were available for review: 26 patients did not have MoM implants, 36 were untraceable, 59 refused follow-up, 87 moved out of area, 147 had died, and 22 already had revision. Of 297 patients, 126 were women and 171 were men; age range was 39 to 95 years (mean age, 69 years); 126 had resurfacing and 171 had MoM replacements. Twenty-six patients had elevated metal ions. Thirty-three patients underwent MARS-MRI: MARS-MRI results were positive in 17 and negative in 16. Of 17 patients with positive MARS-MRI, 10 patients were asymptomatic and seven were waiting revision. CONCLUSIONS: Positive MARS-MRI can often occur in the absence of elevated metal ion levels; elevated blood metal ion levels do not mean MARS-MRI will be positive. All patients with MoM replacements were at risk. It is imperative to assess patients regularly for symptoms that may raise clinical suspicion and maintain a low threshold to performing MARS-MRI.

Silencing of LncRNA-ANCR Promotes the Osteogenesis of Osteoblast Cells in Postmenopausal Osteoporosis via Targeting EZH2 and RUNX2

PURPOSE: This study aimed to explore the effects and mechanisms of long non-coding RNA (lncRNA) anti-differentiation non-coding RNA (ANCR) on the osteogenesis of osteoblast cells in postmenopausal osteoporosis (PMOP). MATERIALS AND METHODS: Mice models of PMOP were established. ANCR expression and intracellular calcium ions were detected by quantitative real-time polymerase chain reaction (qRT-PCR) and laser confocal microscopy, respectively. ANCR was silenced in osteoblast cells from PMOP mice by the transfection of siRNA-ANCR (si-ANCR). The proliferation and apoptosis of osteoblast cells was analyzed by MTT and flow cytometry, respectively. Alkaline phosphatase (ALP) activity and calcium nodules were examined by ALP and alizarin red staining assay, respectively. The expression of enhancer of zeste homolog 2 (EZH2), runt related transcription factor 2 (RUNX2), and OSTERIX was detected by qRT-PCR and Western blot. Furthermore, an osteogenesis model was constructed in mice, and osteoid formation was observed by hematoxylin-eosin (HE) staining. The interaction between lncRNA-ANCR and EZH2 was further identified by RNA pull-down assay. RESULTS: ANCR expression and intracellular calcium ions were increased in PMOP mice. Si-ANCR significantly increased the proliferation, ALP activity, calcium deposition of osteoblast cells and decreased apoptosis. ANCR and EZH2 were down-regulated by si-ANCR, while RUNX2 and OSTERIX were upregulated. Si-ANCR also promoted osteoid formation in mice treated with hydroxyapatite-tricalcium phosphate. In addition, ANCR specifically bound to EZH2. CONCLUSION: Silencing ANCR promotes the osteogenesis of PMOP osteoblast cells. The specific binding of ANCR with EZH2 suppressed RUNX2, thereby inhibiting osteogenesis.

Three-dimensional Printed Mg-Doped b-TCP Bone Tissue Engineering Scaffolds: Effects of Magnesium Ion Concentration on Osteogenesis and Angiogenesis In Vitro

BACKGROUND: Three-dimensional (3D) printed bone tissue engineering scaffolds have been widely used in research and clinical applications. β-TCP is a biomaterial commonly used in bone tissue engineering to treat bone defects, and its multifunctionality can be achieved by co-doping different metal ions. Magnesium doping in biomaterials has been shown to alter physicochemical properties of cells and enhance osteogenesis. METHODS: A series of Mg-doped TCP scaffolds were manufactured by using cryogenic 3D printing technology and sintering. The characteristics of the porous scaffolds, such as microstructure, chemical composition, mechanical properties, apparent porosity, etc., were examined. To further study the role of magnesium ions in simultaneously inducing osteogenesis and angiogenesis, human bone marrow mesenchymal stem cells (hBMSCs) and human umblical vein endothelial cells (HUVECs) were cultured in scaffold extracts to investigate cell proliferation, viability, and expression of osteogenic and angiogenic genes. RESULTS: The results showed that Mg-doped TCP scaffolds have the advantages of precise design, interconnected porous structure, and similar compressive strength to natural cancellous bone. hBMSCs and HUVECs exhibit high proliferation rate, cell morphology and viability in a certain amount of Mg²⁺. In addition, this concentration of magnesium can also increase the expression levels of osteogenic and angiogenic biomarkers. CONCLUSION: A certain concentration of magnesium ions plays an important role in new bone regeneration and reconstruction. It can be used as a simple and effective method to enhance the osteogenesis and angiogenesis of bioceramic scaffolds, and support the development of biomaterials and bone tissue engineering scaffolds.

Preparation and Characterization of Nanocomposite Scaffolds (Collagen/β-TCP/SrO) for Bone Tissue Engineering

BACKGROUND: Nowadays, production of nanocomposite scaffolds based on natural biopolymer, bioceramic, and metal ions is a growing field of research due to the potential for bone tissue engineering applications. METHODS: In this study, a nanocomposite scaffold for bone tissue engineering was successfully prepared using collagen (COL), beta-tricalcium phosphate (β-TCP) and strontium oxide (SrO). A composition of β-TCP (4.9 g) was prepared by doping with SrO (0.05 g). Biocompatible porous nanocomposite scaffolds were prepared by freeze-drying in different formulations [COL, COL/β-TCP (1:2 w/w), and COL/β-TCP-Sr (1:2 w/w)] to be used as a provisional matrix or scaffold for bone tissue engineering. The nanoparticles were characterized by X-ray diffraction, Fourier transforms infrared spectroscopy and energy dispersive spectroscopy. Moreover, the prepared scaffolds were characterized by physicochemical properties, such as porosity, swelling ratio, biodegradation, mechanical properties, and biomineralization. RESULTS: All the scaffolds had a microporous structure with high porosity (~ 95–99%) and appropriate pore size (100–200 µm). COL/β-TCP-Sr scaffolds had the compressive modulus (213.44 ± 0.47 kPa) higher than that of COL/β-TCP (33.14 ± 1.77 kPa). In vitro cytocompatibility, cell attachment and alkaline phosphatase (ALP) activity studies performed using rat bone marrow mesenchymal stem cells. Addition of β-TCP-Sr to collagen scaffolds increased ALP activity by 1.33–1.79 and 2.92–4.57 folds after 7 and 14 days of culture, respectively. CONCLUSION: In summary, it was found that the incorporation of Sr into the collagen-β-TCP scaffolds has a great potential for bone tissue engineering applications.

Imaging and analysis of genetically encoded calcium indicators linking neural circuits and behaviors

Confirming the direct link between neural circuit activity and animal behavior has been a principal aim of neuroscience. The genetically encoded calcium indicator (GECI), which binds to calcium ions and emits fluorescence visualizing intracellular calcium concentration, enables detection of in vivo neuronal firing activity. Various GECIs have been developed and can be chosen for diverse purposes. These GECI-based signals can be acquired by several tools including two-photon microscopy and microendoscopy for precise or wide imaging at cellular to synaptic levels. In addition, the images from GECI signals can be analyzed with open source codes including constrained non-negative matrix factorization for endoscopy data (CNMF_E) and miniscope 1-photon-based calcium imaging signal extraction pipeline (MIN1PIPE), and considering parameters of the imaged brain regions (e.g., diameter or shape of soma or the resolution of recorded images), the real-time activity of each cell can be acquired and linked with animal behaviors. As a result, GECI signal analysis can be a powerful tool for revealing the functions of neuronal circuits related to specific behaviors.

The role of calmodulin in regulating calcium-permeable PKD2L1 channel activity

Polycystic kidney disease 2-like-1 (PKD2L1), polycystin-L or transient receptor potential polycystin 3 (TRPP3) is a TRP superfamily member. It is a calcium-permeable non-selective cation channel that regulates intracellular calcium concentration and thereby calcium signaling. Although the calmodulin (CaM) inhibitor, calmidazolium, is an activator of the PKD2L1 channel, the activating mechanism remains unclear. The purpose of this study is to clarify whether CaM takes part in the regulation of the PKD2L1 channel, and if so, how. With patch clamp techniques, we observed the current amplitudes of PKD2L1 significantly reduced when coexpressed with CaM and CaMΔN. This result suggests that the N-lobe of CaM carries a more crucial role in regulating PKD2L1 and guides us into our next question on the different functions of two lobes of CaM. We also identified the predicted CaM binding site, and generated deletion and truncation mutants. The mutants showed significant reduction in currents losing PKD2L1 current-voltage curve, suggesting that the C-terminal region from 590 to 600 is crucial for maintaining the functionality of the PKD2L1 channel. With PKD2L1608Stop mutant showing increased current amplitudes, we further examined the functional importance of EF-hand domain. Along with co-expression of CaM, ΔEF-hand mutant also showed significant changes in current amplitudes and potentiation time. Our findings suggest that there is a constitutive inhibition of EF-hand and binding of CaM C-lobe on the channel in low calcium concentration. At higher calcium concentration, calcium ions occupy the N-lobe as well as the EF-hand domain, allowing the two to compete to bind to the channel.

Two Manganese Peroxidases and a Laccase of Trametes polyzona KU-RNW027 with Novel Properties for Dye and Pharmaceutical Product Degradation in Redox Mediator-Free System

Two manganese peroxidases (MnPs), MnP1 and MnP2, and a laccase, Lac1, were purified from Trametes polyzona KU-RNW027. Both MnPs showed high stability in organic solvents which triggered their activities. Metal ions activated both MnPs at certain concentrations. The two MnPs and Lac1, played important roles in dye degradation and pharmaceutical products deactivation in a redox mediator-free system. They completely degraded Remazol brilliant blue (25 mg/L) in 10–30 min and showed high degradation activities to Remazol navy blue and Remazol brilliant yellow, while Lac1 could remove 75% of Remazol red. These three purified enzymes effectively deactivated tetracycline, doxycycline, amoxicillin, and ciprofloxacin. Optimal reaction conditions were 50 °C and pH 4.5. The two MnPs were activated by organic solvents and metal ions, indicating the efficacy of using T. polyzona KU-RNW027 for bioremediation of aromatic compounds in environments polluted with organic solvents and metal ions with no need for redox mediator supplements.