ABSTRACT
BACKGROUND: Preliminary study has shown that the composite materials composed of magnesium-based materials and mineralized collagen have a good supporting effect on repairing the critical defects, which can improve the mechanical strength of mineralized collagen and premature collapse during bone healing to some extent. However, magnesium-based metals degrade fast in chloride-containing solutions (including human body fluids or plasma), and the effects of releasing magnesium ions on the proliferation and differentiation of osteoblasts are unknown. OBJECTIVVE: To investigate the effects of magnesium ion combined with mineralized collagen on osteogenic differentiation of mouse preosteoblasts in vitro. METHODS: Mineralized collagen extracts were prepared from complete medium with magnesium ion concentration of 0, 5, 10, and 20 mmol/L. Mouse preosteoblasts were cultured with four mineralized collagen extracts, respectively, which were divided into mineralized collagen group, and 5, 10 and 20 mmol/L Mg2++mineralized collagen groups. The mouse preosteoblasts cultured in complete medium were used as control group. The cell morphology, proliferation, apoptosis, intracellular microfilament actin, and the activity of alkaline phosphatase and expression level of the osteogenic gene Runx2 after osteogenic differentiation were detected. RESULTS AND CONCLUSION: (1) After 24 hours of culture, the cells in the mineralized collagen group, and 5 and 10 mmol/L Mg2++ mineralized collagen groups adhered well, which showed no significant difference from the blank control group, and the elongated spindle cells with many synapses linked to the adjacent cells were observed. The cells in the 20 mmol/L Mg2++mineralized collagen group showed obvious pyknosis. (2) After 1, 3 and 5 days of culture, the cell viability in the 10 mmol/L Mg2++mineralized collagen group was significantly higher than that in the other four groups (P 0.05). The cell viability in the 20 mmol/L Mg2++mineralized collagen group was significantly lower than that in the mineralized collagen group (P < 0.05). (3) After 3 days of culture, DAPI staining showed that 20 mmol/L Mg2++mineralized collagen group had obvious nuclear disintegration, the other four groups had no obvious nuclear disintegration. (4) After 24 hours of culture, phalloidin staining showed that except the blank control and 20 mmol/L Mg2++mineralized collagen groups, the other three groups showed completely extended cell structure, and clear actin microfilaments, especially the 10 mmol/L Mg2++mineralized collagen group. (5) After 7 days of osteogenic differentiation, except for 20 mmol/L Mg2++mineralized collagen group, the activity of alkaline phosphatase and the expression level of Runx2 gene in the other three groups were significantly higher than those in the blank control group (P < 0.05), and those in the 10 mmol/L Mg2++mineralized collagen group was significantly higher than those in the 5 mmol/L Mg2++mineralized collagen and mineralized collagen groups (P < 0.05). (6) These results suggest that the combination of magnesium ion with mineralized collagen should be applied with appropriate concentration range of magnesium ion (≤ 10 mmol/L).
ABSTRACT
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.
Subject(s)
Humans , Biocompatible Materials , Biomarkers , Bone and Bones , Bone Marrow , Bone Regeneration , Cell Proliferation , Compressive Strength , Endothelial Cells , In Vitro Techniques , Ions , Magnesium , Mesenchymal Stem Cells , Methods , Osteogenesis , Porosity , Printing, Three-Dimensional , VeinsABSTRACT
La determinación de Dureza Total con EDTA en agua usando una solución amortiguadora de amonio pH 10 tiene la desventaja de generar vapores de gas amoníaco que suelen ser molestos o ser potencialmente dañinos para el sistema respiratorio del operario. El objetivo de este estudio fue utilizar una solución amortiguadora inodora de borato pH 10 en sustitución de una solución amortiguadora de amonio a pH 10 para la determinación de la dureza total en agua por la metodología de la norma COVENIN 2408-86 y determinar si existía diferencia estadísticamente significativa entre ambos procedimientos. Se determinó la Dureza Total usando la solución amortiguadora inodora de borato en 13 muestras de agua con diferentes grados de dureza (suave, dura y muy dura); los resultados obtenidos se compararon con los valores del procedimiento de referencia. La solución amortiguadora permitió una visualización rápida y definida del punto final durante la ejecución de la determinación volumétrica, los resultados mostraron que no existe diferencia estadísticamente significativa (p≤0,05) en los valores de dureza al emplear ambas soluciones amortiguadoras. Se concluyó que el empleo de la solución amortiguadora inodora de borato para la cuantificación de dureza total en agua es una alternativa a la solución amortiguadora de amonio.
Total Hardness determination EDTA in water using ammonium buffer solution pH 10 has the disadvantage of generating ammonia gas vapors are usually upset or be potentially harmful to the respiratory system operator. The aim of this study was to use a buffer solution pH 10 borate odorless replacing ammonium buffer solution at pH 10 for the determination of total water hardness in the methodology of COVENIN 2408-86 standard and determine whether there was difference statistically significant between the two procedures. Total Hardness was determined using borate buffer odorless in 13 water samples with different degrees of hardness (soft, hard and very hard); the results obtained were compared with the reference method values. The buffer allowed rapid and sharp display of the end point during the execution of the volumetric determination, the results showed that there was no statistically significant difference (p≤ 0,05) in hardness values by using two buffers. It was concluded that the use of borate buffer odorless for quantification of total hardness water is an alternative to the ammonium buffer.
Subject(s)
Humans , Male , Female , Water Quality/standards , Borates/pharmacology , Water Hardness/analysis , Calcium , Public Health , MagnesiumABSTRACT
Objective:To determine blood magnesium and urinary magnesium in children with asthma exacerbation and discuss the relationship between the magnesium level and children with asthma attack. Methods:The observation group include 90 children who were 0~6 years old with asthma exacerbation that admission to our hospital since May 2008 to May 2012. The control group was 100 children with the same age to the observation group to accept the health examination. Every child in two groups were taking venous blood of 2ml and 24h urine samples. Record the amount of urine at the same time. Using automatic biochemical analyzer to detect the serum magnesium concentration and urinary magnesium concentration. Results: The urinary magnesium concentration of observation group was obviously lower than control group (t=8.52, P0.05). Conclusion:Children with asthma in acute attack stage with magnesium deficiency. Urinary magnesium concentration determination is simple, and it is a effective method that can be used to judge whether there is magnesium deficiency. Serum magnesium concentration cannot be used as a reliable indicator of magnesium ion balance.