Introduction: While autograft bone is the gold standard for multilevel posterolateral lumbar fusion, bone substitutes and graft extenders such as allograft bone, ceramics and demineralized bone matrix (DBM) have been ...Introduction: While autograft bone is the gold standard for multilevel posterolateral lumbar fusion, bone substitutes and graft extenders such as allograft bone, ceramics and demineralized bone matrix (DBM) have been used to avoid the morbidity and insufficient quantity associated with harvesting autologous bone. The primary objective of this retrospective study was to determine whether, in patients with increased risk of operative nonunion related to multilevel fusion, adding DBM fibers to mineralized bone allograft resulted in better fusion than using allograft alone. The secondary objectives were to evaluate how adding DBM fibers affects functional disability, low back pain, intraoperative blood loss and the nonunion rate. Methods: This retrospective study involved a chart review of consecutive patients who underwent multilevel lumbar spinal fusion and were operated on by a single surgeon. The patients were divided into two groups: 14 patients received mineralized bone allograft (control group) and 14 patients received a combination of mineralized bone allograft and DBM (experimental group). Patients were reviewed at a mean of 16.4 ± 2.2 months after surgery at which point CT scans were analyzed to determine whether fusion had occurred;Oswestry disability index (ODI) and pain were also evaluated. Results: A mean of 5 levels [min 2, max 13] were fused in these patients. Posterolateral fusion as defined by the Lenke classification was not significantly different between groups. The experimental DBM group had a significantly better composite fusion score than the control group (P Discussion: Adding DBM fibers to allograft bone during multilevel posterolateral spinal fusion was safe and produced better composite fusion than using allograft only as an autograft extender.展开更多
Autologous bone graft is considered as the gold standard for all indications for bone grafting procedures but the limited availability and complications in donor site resulted in seeking other options like allografts ...Autologous bone graft is considered as the gold standard for all indications for bone grafting procedures but the limited availability and complications in donor site resulted in seeking other options like allografts andbone graft substitutes. Demineralized bone matrix(DBM) is an allograft product with no quantity limitation. It is an osteoconductive material with osteoinductive capabilities, which vary among different products, depending on donor characteristics and differences in processing of the bone. The purpose of the present review is to provide a critical review of the existing literature concerning the use of DBM products in various procedures in the extremities. Clinical studies describing the use of DBM alone or in combination with other grafting material are available for only a few commercial products. The Level of Evidence of these studies and the resulting Grades of Recommendation are very low. In conclusion, further clinical studies of higher quality are required in order to improve the Recommendation Grades for or against the use of DBM products in bone grafting procedures.展开更多
Spinal fusion remains the gold-standard treatment for several pathological spine conditions. Although, autologous Iliac Crest Bone Grafting is considered the goldstandard graft choice to promote spinal fusion; however...Spinal fusion remains the gold-standard treatment for several pathological spine conditions. Although, autologous Iliac Crest Bone Grafting is considered the goldstandard graft choice to promote spinal fusion; however, it is associated with significant donor site morbidity and a limited graft quantity. Therefore, several bone graft alternatives have been developed, to augment arthrodesis. The purpose of this review is to present the results of clinical studies concerning the use of demineralized bone matrix(DBM), alone or as a composite graft, in the spinal fusion. A critical review of the English-language literature was conducted on Pubmed, using key word "demineralized bone matrix", "DBM", "spinal fusion", and "scoliosis". Results had been restricted to clinical studies. The majority of clinical trials demonstrate satisfactory fusion rates when DBM is employed as a graft extender or a graft enhancer.Limited number of prospective randomized controlled trials(4 studies), have been performed comparing DBM to autologous iliac crest bone graft in spine fusion. The majority of the clinical trials demonstrate comparable efficacy of DBM when it used as a graft extender in combination with autograft, but there is no clinical evidence to support its use as a standalone graft material. Additionally, high level of evidence studies are required, in order to optimize and clarify the indications of its use and the appropriate patient population that will benefit from DBM in spine arthrodesis.展开更多
Adolescent idiopathic scoliosis （AIS） is one of the most prevalent diseases among teenagers, with an incidence rate of 1-3% worldwide, and at least 0.02% of patients require surgical treatment. The ＂gold standard＂...Adolescent idiopathic scoliosis （AIS） is one of the most prevalent diseases among teenagers, with an incidence rate of 1-3% worldwide, and at least 0.02% of patients require surgical treatment. The ＂gold standard＂ procedure is instrumentation and fusion of 10 or more vertebrae with forceful correction of the deformity.Although autogenous bone grafts are the ＂gold standard＂ for spine fusion, significant progress has been made in discovering bone graft alternatives, including freeze-dried allograft, demineralized bone matrix （DBM）, triosite ceramics, and bone marrow aspirate （BMA）, which have been used as substitutes for iliac crest in AIS surgery.展开更多
Background: Caries detection in school oral examinations insufficient accuracy. Objective: To evaluate advantages of introducing quantitative light-induced fluorescence-digital (QLF-D) in school oral examinations. Met...Background: Caries detection in school oral examinations insufficient accuracy. Objective: To evaluate advantages of introducing quantitative light-induced fluorescence-digital (QLF-D) in school oral examinations. Methods: Experiment No. 1. Early demineralized lesions in the upper and lower incisors and canines were visually inspected by three dentists and by QLF-D. The numbers of tooth planes with early demineralized lesions were compared between the methods. Experiment No. 2. Approximal demineralized lesions in molars were assessed by visual inspection, x-ray imaging, and QLF-D. The numbers of tooth planes with demineralized lesions were compared among the methods. Experiment No. 3. Plaque distribution was evaluated by QLF-D and a traditional staining method. The ratio of the diameter of plaque to tooth crown in the tooth axis direction in each method was calculated. The results were evaluated by Pearson’s correlation coefficient analysis and Bland-Altman plot. Results: Experiment No. 1. The three dentists found 0.67 tooth planes on average. QLF-D found 22 tooth planes with early demineralized lesions in the same samples. Experiment No. 2. Fourteen approximal tooth planes of molars were found to have demineralized lesions by x-ray imaging. QLF-D detected 71.4% of the tooth planes out of the 14, whereas visual inspection found 7.1%. Experiment No. 3. The Pearson’s correlation coefficient for the evaluations of plaque distribution between the QLF-D and traditional staining methods was 0.77 (P Conclusion: The results support introduction of QLF-D for use in school dental examinations.展开更多
The self-made demineralized teeth samples treated with preamble resin to seal or not were observed under electron microscopy and tested microhardness value to show surface structure and hardness of demineralized ename...The self-made demineralized teeth samples treated with preamble resin to seal or not were observed under electron microscopy and tested microhardness value to show surface structure and hardness of demineralized enamel.The experimental results showed that the permeable resin formed longer resin tags on the surface of the enamel and a lot of cracks in the deep part which has a higher microhardness value than ordinary enamel.展开更多
AIM To assess use of demineralized bone matrix(DBM) use in anterior cervical discectomy and fusion(ACDF) in outpatient setting.METHODS One hundred and forty-five patients with prospectively collected data undergoing s...AIM To assess use of demineralized bone matrix(DBM) use in anterior cervical discectomy and fusion(ACDF) in outpatient setting.METHODS One hundred and forty-five patients with prospectively collected data undergoing single and two level ACDF with DBM packed within and anterior to polyetheretherketone(PEEK) cages. Two groups created, Group 1(75) outpatients and control Group 2(70) hospital patients. Prevertebral soft tissue swelling(PVSTS) was measured anterior to C2 and C6 on plain lateral cervical radiographs preoperatively and one week postoperatively and fusion assessed at two years. RESULTS There was no intergroup significance between preoperative and postoperative visual analogue scales(VAS)and neck disability index(NDI) scores between Group 1 and 2. Mean preoperative PVSTS in Group 1 was 4.7 ± 0.2 mm at C2 level and 11.1 ± 0.5 at C6 level compared to Group 2 mean PVSTS of 4.5 ± 0.5 mm and 12.8 ± 0.5, P = 0.172 and 0.127 respectively. There was no radiographic or clinical evidence of adverse reaction noted. In Group 1 mean postoperative PVSTS was 5.5 ± 0.4 mm at C2 and 14.9 ± 0.6 mm at C6 compared Group 2 mean PVSTS was 4.9 ± 0.3 mm at C2 and 14.8 ± 0.5 mm at C6, P = 0.212 and 0.946 respectively. No significant increase in prevertebral soft tissue space at C2 and C6 level demonstrated.CONCLUSION ACDF with adjunct DBM packed PEEK cages showed a statistical significant intragroup improvement in VAS neck pain scores and NDI scores(P = 0.001). There were no reported serious patient complications; post-operative radiographs demonstrated no significant difference in prevertebral space. We conclude that ACDF with DBMpacked PEEK cages can be safely done in an ASC with satisfactory outcomes.展开更多
A major part of world is facing water shortages today. While the world’s population has grown to more than 7.75 billion, the quantity of sweet water has remained the same. The ever increasing use of water by such a l...A major part of world is facing water shortages today. While the world’s population has grown to more than 7.75 billion, the quantity of sweet water has remained the same. The ever increasing use of water by such a large population has resulted in pollution of many water sources. The developing world where a large fraction of total world population is located faces water scarcity in a more severe manner than the developed world. The developed world has managed to control human population and preserve natural water resources more effectively. As a result of this and also due to stabilized population, they face lesser problems for water availability. Indian population stands at 1.386 billion as nowadays. The erratic monsoon rains over last few years have resulted in floods and subsequent water shortages in summer months in major part of the country. A similar situation is faced by many Asian and African countries. The means of recycling and using every possible source of water are always welcome in these countries. Since many of these countries lie in tropical or semitropical zone, the average relative humidity is more than 50% for most of the year. Changing life styles in these countries and spread of information technology based sectors have resulted in a growth spurt in air conditioning facilities. An air conditioner draws heat from surrounding air and cools the premises to desired temperature. During this process, a large amount of moisture in the atmosphere gets condensed and is drained out. There are no efforts made to recover this water in India and neighbouring countries. We have undertaken studies to check the quality of this water and see the feasibility of its use in a decentralized but effective manner. The results show that this water condensate from air conditioners is highly pure, substantial and available almost round the year. This can help in recovering millions of litres of good quality water daily. This water would find uses in industries, laboratories, households and farming. It would also cr展开更多
Studies show that human amniotic cells’ pluripotentency can be influenced to produce chondrocytes and osteocytes through adding demineralized bone (DMB). Objective: This study evaluates the human amniotic membrane (H...Studies show that human amniotic cells’ pluripotentency can be influenced to produce chondrocytes and osteocytes through adding demineralized bone (DMB). Objective: This study evaluates the human amniotic membrane (HAM) mixed with DMB to fill defects in sheep models. We hypothesized this membrane would fill these defects with hyaline-like cartilage with chondrocytes populating the matrix. Design: Six adult sheep were used in this study. One hindquarter knee of each sheep was utilized to make two cartilage defects: one on the femoral condyle and one in the trochlear grove. Three control sheep had unfilled defects. Three sheep received HAM/DMB from a placenta to fill the defects. The membrane was folded so the cellular layer faced the defect and the joint while demineralized bone was placed between the layers. The membranes were fixed to the femur and to the trochlear grove. At six months, the sheep were sacrificed for evaluation. Results: Of the controls, defects did not fill with hyaline or fibrocartilage. In HAM/DMB sheep, 50% of the defects retained the membrane, consistent with other animal models. Membrane defects were examined histologically by a validated scoring system. A strong correlation of little statistical difference between the test and the normal cartilages was observed. The defects that retained membranes had evidence of diffuse chondrocyte-like cell proliferation of stromal matrix similar to hyaline cartilage. Conclusions: HAM/DMB is a potential source of pluripotent cells that can influence chondrogenesis in defects in sheep models. The implications for application in a human model are promising and warrant further study.展开更多
As a scaffold material for bone tissue engineering, demineralized bone matrix(DBM) has such a limited ability to load cells and growth factors that the surface of the DBM scaffold was modified with bovine serum albumi...As a scaffold material for bone tissue engineering, demineralized bone matrix(DBM) has such a limited ability to load cells and growth factors that the surface of the DBM scaffold was modified with bovine serum albumin(BSA) with different concentrations to improve the protein stmcture and physicochemical properties of the scaffold surface so as to enhance the adhesion of the cells. And the appropriate BSA concentration was explored. Compared with DBM, the scaffold with BSA coating had a smaller pore size and a lower porosity, also, the degradation rate was accelerated and the hydrophilic property was improved. Cells adhesion was observed inside the DBM seaffold before and after it had been modified, and the BSA modified scaffold had a good cell compatibility. Wlien the concentration of BSA was 20 mg/mL, the adhesion ability of the cells to modified scaffold was significantly increased, and the cell proliferation was facilitated.展开更多
Demineralized bone matrix(DBM)has been widely used clinically for dental,craniofacial and skeletal bone repair,as an osteoinductive and osteoconductive material.3D printing(3DP)enables the creation of bone tissue engi...Demineralized bone matrix(DBM)has been widely used clinically for dental,craniofacial and skeletal bone repair,as an osteoinductive and osteoconductive material.3D printing(3DP)enables the creation of bone tissue engineering scaffolds with complex geometries and porosity.Photoreactive methacryloylated gelatin nanoparticles(GNP-MAs)3DP inks have been developed,which display gel-like behavior for high print fidelity and are capable of post-printing photocrosslinking for control of scaffold swelling and degradation.Here,novel DBM nanoparticles(DBM-NPs,∼400 nm)were fabricated and characterized prior to incorporation in 3DP inks.The objectives of this study were to determine how these DBM-NPs would influence the printability of composite colloidal 3DP inks,assess the impact of ultraviolet(UV)crosslinking on 3DP scaffold swelling and degradation and evaluate the osteogenic potential of DBM-NP-containing composite colloidal scaffolds.The addition of methacryloylated DBM-NPs(DBM-NP-MAs)to composite colloidal inks(100:0,95:5 and 75:25 GNP-MA:DBM-NP-MA)did not significantly impact the rheological properties associated with printability,such as viscosity and shear recovery or photocrosslinking.UV crosslinking with a UV dosage of 3 J/cm2 directly impacted the rate of 3DP scaffold swelling for all GNP-MA:DBM-NP-MA ratios with an∼40%greater increase in scaffold area and pore area in uncrosslinked versus photocrosslinked scaffolds over 21 days in phosphate-buffered saline(PBS).Likewise,degradation(hydrolytic and enzymatic)over 21 days for all DBM-NP-MA content groups was significantly decreased,∼45%less in PBS and collagenase-containing PBS,in UV-crosslinked versus uncrosslinked groups.The incorporation of DBM-NP-MAs into scaffolds decreased mass loss compared to GNP-MA-only scaffolds during collagenase degradation.An in vitro osteogenic study with bone marrow-derived mesenchymal stem cells demonstrated osteoconductive properties of 3DP scaffolds for the DBM-NP-MA contents examined.The creation of photoreactive DBM-NP-MAs展开更多
Matrix stiffness has been demonstrated in many studies to adjust the biological behaviors of mesenchymal stem cells (MSCs). However, in the initial phase of bone restore, MSCs will encounter a hypoxic microenvironment...Matrix stiffness has been demonstrated in many studies to adjust the biological behaviors of mesenchymal stem cells (MSCs). However, in the initial phase of bone restore, MSCs will encounter a hypoxic microenvironment. Studying the connection existing between the matrix stiffness and biological behavior of MSCs under hypoxic condition can better simulate the microenvironment at the prime period of bone repairment. In this work, three-dimensional (3D) decalcified bone scaffolds with diverse stiffness (high stiffness (66.06 ± 27.83) MPa, medium stiffness (26.90 ± 13.16) MPa, and low stiffness (0.67 ± 0.14) MPa) but same microstructure have been prepared by controlling decalcification time. In addition, the decellularized bone scaffold was regard as control group and its stiffness was (230.93 ± 72.65) MPa. The viability, proliferation, infiltration, and osteogenic differentiation of MSCs seeded into these 3D demineralized bone scaffolds were systematically investigated under 100 μM CoCl2-simulated hypoxic and normoxic environments. The results showed that the viability, proliferation, and extracellular matrix (ECM) secretion of MSCs had no significant difference on scaffolds with diverse stiffness but the degree of collagen deposition of MSCs gradually increased with the increase of scaffold stiffness both under normoxia and hypoxia. Compared to normoxia, the viability, proliferation, ECM secretion, vascular endothelial growth factor (VEGF) expression, and osteogenis of MSCs on the scaffolds with the same stiffness were evidently inhibited by hypoxia. Additionally, under hypoxic condition, the expression of VEGF and hypoxia inducible factor 1α(HIF-1α) in MSCs on the low stiffness scaffold was markedly increased comparing to those on other groups. In summary, we found that the low stiffness scaffold can improved the proliferation and osteoginic differentiation of MSCs under hypoxic environment, which may help to explore efficient methods for bone defect repairing.展开更多
文摘Introduction: While autograft bone is the gold standard for multilevel posterolateral lumbar fusion, bone substitutes and graft extenders such as allograft bone, ceramics and demineralized bone matrix (DBM) have been used to avoid the morbidity and insufficient quantity associated with harvesting autologous bone. The primary objective of this retrospective study was to determine whether, in patients with increased risk of operative nonunion related to multilevel fusion, adding DBM fibers to mineralized bone allograft resulted in better fusion than using allograft alone. The secondary objectives were to evaluate how adding DBM fibers affects functional disability, low back pain, intraoperative blood loss and the nonunion rate. Methods: This retrospective study involved a chart review of consecutive patients who underwent multilevel lumbar spinal fusion and were operated on by a single surgeon. The patients were divided into two groups: 14 patients received mineralized bone allograft (control group) and 14 patients received a combination of mineralized bone allograft and DBM (experimental group). Patients were reviewed at a mean of 16.4 ± 2.2 months after surgery at which point CT scans were analyzed to determine whether fusion had occurred;Oswestry disability index (ODI) and pain were also evaluated. Results: A mean of 5 levels [min 2, max 13] were fused in these patients. Posterolateral fusion as defined by the Lenke classification was not significantly different between groups. The experimental DBM group had a significantly better composite fusion score than the control group (P Discussion: Adding DBM fibers to allograft bone during multilevel posterolateral spinal fusion was safe and produced better composite fusion than using allograft only as an autograft extender.
文摘Autologous bone graft is considered as the gold standard for all indications for bone grafting procedures but the limited availability and complications in donor site resulted in seeking other options like allografts andbone graft substitutes. Demineralized bone matrix(DBM) is an allograft product with no quantity limitation. It is an osteoconductive material with osteoinductive capabilities, which vary among different products, depending on donor characteristics and differences in processing of the bone. The purpose of the present review is to provide a critical review of the existing literature concerning the use of DBM products in various procedures in the extremities. Clinical studies describing the use of DBM alone or in combination with other grafting material are available for only a few commercial products. The Level of Evidence of these studies and the resulting Grades of Recommendation are very low. In conclusion, further clinical studies of higher quality are required in order to improve the Recommendation Grades for or against the use of DBM products in bone grafting procedures.
文摘Spinal fusion remains the gold-standard treatment for several pathological spine conditions. Although, autologous Iliac Crest Bone Grafting is considered the goldstandard graft choice to promote spinal fusion; however, it is associated with significant donor site morbidity and a limited graft quantity. Therefore, several bone graft alternatives have been developed, to augment arthrodesis. The purpose of this review is to present the results of clinical studies concerning the use of demineralized bone matrix(DBM), alone or as a composite graft, in the spinal fusion. A critical review of the English-language literature was conducted on Pubmed, using key word "demineralized bone matrix", "DBM", "spinal fusion", and "scoliosis". Results had been restricted to clinical studies. The majority of clinical trials demonstrate satisfactory fusion rates when DBM is employed as a graft extender or a graft enhancer.Limited number of prospective randomized controlled trials(4 studies), have been performed comparing DBM to autologous iliac crest bone graft in spine fusion. The majority of the clinical trials demonstrate comparable efficacy of DBM when it used as a graft extender in combination with autograft, but there is no clinical evidence to support its use as a standalone graft material. Additionally, high level of evidence studies are required, in order to optimize and clarify the indications of its use and the appropriate patient population that will benefit from DBM in spine arthrodesis.
基金grants from the National Natural Science Foundation of China，Shanghai Natural Science Foundation，Youth Project of Shanghai Municipal Health and Family Planning Commission
文摘Adolescent idiopathic scoliosis （AIS） is one of the most prevalent diseases among teenagers, with an incidence rate of 1-3% worldwide, and at least 0.02% of patients require surgical treatment. The ＂gold standard＂ procedure is instrumentation and fusion of 10 or more vertebrae with forceful correction of the deformity.Although autogenous bone grafts are the ＂gold standard＂ for spine fusion, significant progress has been made in discovering bone graft alternatives, including freeze-dried allograft, demineralized bone matrix （DBM）, triosite ceramics, and bone marrow aspirate （BMA）, which have been used as substitutes for iliac crest in AIS surgery.
文摘Background: Caries detection in school oral examinations insufficient accuracy. Objective: To evaluate advantages of introducing quantitative light-induced fluorescence-digital (QLF-D) in school oral examinations. Methods: Experiment No. 1. Early demineralized lesions in the upper and lower incisors and canines were visually inspected by three dentists and by QLF-D. The numbers of tooth planes with early demineralized lesions were compared between the methods. Experiment No. 2. Approximal demineralized lesions in molars were assessed by visual inspection, x-ray imaging, and QLF-D. The numbers of tooth planes with demineralized lesions were compared among the methods. Experiment No. 3. Plaque distribution was evaluated by QLF-D and a traditional staining method. The ratio of the diameter of plaque to tooth crown in the tooth axis direction in each method was calculated. The results were evaluated by Pearson’s correlation coefficient analysis and Bland-Altman plot. Results: Experiment No. 1. The three dentists found 0.67 tooth planes on average. QLF-D found 22 tooth planes with early demineralized lesions in the same samples. Experiment No. 2. Fourteen approximal tooth planes of molars were found to have demineralized lesions by x-ray imaging. QLF-D detected 71.4% of the tooth planes out of the 14, whereas visual inspection found 7.1%. Experiment No. 3. The Pearson’s correlation coefficient for the evaluations of plaque distribution between the QLF-D and traditional staining methods was 0.77 (P Conclusion: The results support introduction of QLF-D for use in school dental examinations.
文摘The self-made demineralized teeth samples treated with preamble resin to seal or not were observed under electron microscopy and tested microhardness value to show surface structure and hardness of demineralized enamel.The experimental results showed that the permeable resin formed longer resin tags on the surface of the enamel and a lot of cracks in the deep part which has a higher microhardness value than ordinary enamel.
文摘AIM To assess use of demineralized bone matrix(DBM) use in anterior cervical discectomy and fusion(ACDF) in outpatient setting.METHODS One hundred and forty-five patients with prospectively collected data undergoing single and two level ACDF with DBM packed within and anterior to polyetheretherketone(PEEK) cages. Two groups created, Group 1(75) outpatients and control Group 2(70) hospital patients. Prevertebral soft tissue swelling(PVSTS) was measured anterior to C2 and C6 on plain lateral cervical radiographs preoperatively and one week postoperatively and fusion assessed at two years. RESULTS There was no intergroup significance between preoperative and postoperative visual analogue scales(VAS)and neck disability index(NDI) scores between Group 1 and 2. Mean preoperative PVSTS in Group 1 was 4.7 ± 0.2 mm at C2 level and 11.1 ± 0.5 at C6 level compared to Group 2 mean PVSTS of 4.5 ± 0.5 mm and 12.8 ± 0.5, P = 0.172 and 0.127 respectively. There was no radiographic or clinical evidence of adverse reaction noted. In Group 1 mean postoperative PVSTS was 5.5 ± 0.4 mm at C2 and 14.9 ± 0.6 mm at C6 compared Group 2 mean PVSTS was 4.9 ± 0.3 mm at C2 and 14.8 ± 0.5 mm at C6, P = 0.212 and 0.946 respectively. No significant increase in prevertebral soft tissue space at C2 and C6 level demonstrated.CONCLUSION ACDF with adjunct DBM packed PEEK cages showed a statistical significant intragroup improvement in VAS neck pain scores and NDI scores(P = 0.001). There were no reported serious patient complications; post-operative radiographs demonstrated no significant difference in prevertebral space. We conclude that ACDF with DBMpacked PEEK cages can be safely done in an ASC with satisfactory outcomes.
文摘A major part of world is facing water shortages today. While the world’s population has grown to more than 7.75 billion, the quantity of sweet water has remained the same. The ever increasing use of water by such a large population has resulted in pollution of many water sources. The developing world where a large fraction of total world population is located faces water scarcity in a more severe manner than the developed world. The developed world has managed to control human population and preserve natural water resources more effectively. As a result of this and also due to stabilized population, they face lesser problems for water availability. Indian population stands at 1.386 billion as nowadays. The erratic monsoon rains over last few years have resulted in floods and subsequent water shortages in summer months in major part of the country. A similar situation is faced by many Asian and African countries. The means of recycling and using every possible source of water are always welcome in these countries. Since many of these countries lie in tropical or semitropical zone, the average relative humidity is more than 50% for most of the year. Changing life styles in these countries and spread of information technology based sectors have resulted in a growth spurt in air conditioning facilities. An air conditioner draws heat from surrounding air and cools the premises to desired temperature. During this process, a large amount of moisture in the atmosphere gets condensed and is drained out. There are no efforts made to recover this water in India and neighbouring countries. We have undertaken studies to check the quality of this water and see the feasibility of its use in a decentralized but effective manner. The results show that this water condensate from air conditioners is highly pure, substantial and available almost round the year. This can help in recovering millions of litres of good quality water daily. This water would find uses in industries, laboratories, households and farming. It would also cr
文摘Studies show that human amniotic cells’ pluripotentency can be influenced to produce chondrocytes and osteocytes through adding demineralized bone (DMB). Objective: This study evaluates the human amniotic membrane (HAM) mixed with DMB to fill defects in sheep models. We hypothesized this membrane would fill these defects with hyaline-like cartilage with chondrocytes populating the matrix. Design: Six adult sheep were used in this study. One hindquarter knee of each sheep was utilized to make two cartilage defects: one on the femoral condyle and one in the trochlear grove. Three control sheep had unfilled defects. Three sheep received HAM/DMB from a placenta to fill the defects. The membrane was folded so the cellular layer faced the defect and the joint while demineralized bone was placed between the layers. The membranes were fixed to the femur and to the trochlear grove. At six months, the sheep were sacrificed for evaluation. Results: Of the controls, defects did not fill with hyaline or fibrocartilage. In HAM/DMB sheep, 50% of the defects retained the membrane, consistent with other animal models. Membrane defects were examined histologically by a validated scoring system. A strong correlation of little statistical difference between the test and the normal cartilages was observed. The defects that retained membranes had evidence of diffuse chondrocyte-like cell proliferation of stromal matrix similar to hyaline cartilage. Conclusions: HAM/DMB is a potential source of pluripotent cells that can influence chondrogenesis in defects in sheep models. The implications for application in a human model are promising and warrant further study.
文摘As a scaffold material for bone tissue engineering, demineralized bone matrix(DBM) has such a limited ability to load cells and growth factors that the surface of the DBM scaffold was modified with bovine serum albumin(BSA) with different concentrations to improve the protein stmcture and physicochemical properties of the scaffold surface so as to enhance the adhesion of the cells. And the appropriate BSA concentration was explored. Compared with DBM, the scaffold with BSA coating had a smaller pore size and a lower porosity, also, the degradation rate was accelerated and the hydrophilic property was improved. Cells adhesion was observed inside the DBM seaffold before and after it had been modified, and the BSA modified scaffold had a good cell compatibility. Wlien the concentration of BSA was 20 mg/mL, the adhesion ability of the cells to modified scaffold was significantly increased, and the cell proliferation was facilitated.
基金support from a National Science Foundation Graduate Research Fellowship(M.R.P.,E.J.,E.Y.J.)the National Institutes of Health(F31 DE030333,K.J.H.+3 种基金P41 EB023833,A.G.M.)the Baylor College of Medicine Medical Science Training Program(K.J.H.),the Scientific and Technological Research Council of Turkey International Research Fellowship Programme for PhD Students(H.O.)a Rubicon Postdoctoral Fellowship from the Dutch Research Council(NWOProject No.019.182 EN.004)(M.D.).
文摘Demineralized bone matrix(DBM)has been widely used clinically for dental,craniofacial and skeletal bone repair,as an osteoinductive and osteoconductive material.3D printing(3DP)enables the creation of bone tissue engineering scaffolds with complex geometries and porosity.Photoreactive methacryloylated gelatin nanoparticles(GNP-MAs)3DP inks have been developed,which display gel-like behavior for high print fidelity and are capable of post-printing photocrosslinking for control of scaffold swelling and degradation.Here,novel DBM nanoparticles(DBM-NPs,∼400 nm)were fabricated and characterized prior to incorporation in 3DP inks.The objectives of this study were to determine how these DBM-NPs would influence the printability of composite colloidal 3DP inks,assess the impact of ultraviolet(UV)crosslinking on 3DP scaffold swelling and degradation and evaluate the osteogenic potential of DBM-NP-containing composite colloidal scaffolds.The addition of methacryloylated DBM-NPs(DBM-NP-MAs)to composite colloidal inks(100:0,95:5 and 75:25 GNP-MA:DBM-NP-MA)did not significantly impact the rheological properties associated with printability,such as viscosity and shear recovery or photocrosslinking.UV crosslinking with a UV dosage of 3 J/cm2 directly impacted the rate of 3DP scaffold swelling for all GNP-MA:DBM-NP-MA ratios with an∼40%greater increase in scaffold area and pore area in uncrosslinked versus photocrosslinked scaffolds over 21 days in phosphate-buffered saline(PBS).Likewise,degradation(hydrolytic and enzymatic)over 21 days for all DBM-NP-MA content groups was significantly decreased,∼45%less in PBS and collagenase-containing PBS,in UV-crosslinked versus uncrosslinked groups.The incorporation of DBM-NP-MAs into scaffolds decreased mass loss compared to GNP-MA-only scaffolds during collagenase degradation.An in vitro osteogenic study with bone marrow-derived mesenchymal stem cells demonstrated osteoconductive properties of 3DP scaffolds for the DBM-NP-MA contents examined.The creation of photoreactive DBM-NP-MAs
基金the National Natural Science Foundation of China (Grants 11702043 and 11672051 and 11702044)Fundamental Research Funds for the Central Universities (Grant 2018CDQYSG0015).
文摘Matrix stiffness has been demonstrated in many studies to adjust the biological behaviors of mesenchymal stem cells (MSCs). However, in the initial phase of bone restore, MSCs will encounter a hypoxic microenvironment. Studying the connection existing between the matrix stiffness and biological behavior of MSCs under hypoxic condition can better simulate the microenvironment at the prime period of bone repairment. In this work, three-dimensional (3D) decalcified bone scaffolds with diverse stiffness (high stiffness (66.06 ± 27.83) MPa, medium stiffness (26.90 ± 13.16) MPa, and low stiffness (0.67 ± 0.14) MPa) but same microstructure have been prepared by controlling decalcification time. In addition, the decellularized bone scaffold was regard as control group and its stiffness was (230.93 ± 72.65) MPa. The viability, proliferation, infiltration, and osteogenic differentiation of MSCs seeded into these 3D demineralized bone scaffolds were systematically investigated under 100 μM CoCl2-simulated hypoxic and normoxic environments. The results showed that the viability, proliferation, and extracellular matrix (ECM) secretion of MSCs had no significant difference on scaffolds with diverse stiffness but the degree of collagen deposition of MSCs gradually increased with the increase of scaffold stiffness both under normoxia and hypoxia. Compared to normoxia, the viability, proliferation, ECM secretion, vascular endothelial growth factor (VEGF) expression, and osteogenis of MSCs on the scaffolds with the same stiffness were evidently inhibited by hypoxia. Additionally, under hypoxic condition, the expression of VEGF and hypoxia inducible factor 1α(HIF-1α) in MSCs on the low stiffness scaffold was markedly increased comparing to those on other groups. In summary, we found that the low stiffness scaffold can improved the proliferation and osteoginic differentiation of MSCs under hypoxic environment, which may help to explore efficient methods for bone defect repairing.
