BACKGROUND The epiphyseal growth plate is an important anatomical segment localized on the ends of a long bone.Despite the abovementioned atractive reasons for alendronate’s use,few data on the effect of alendronate ...BACKGROUND The epiphyseal growth plate is an important anatomical segment localized on the ends of a long bone.Despite the abovementioned atractive reasons for alendronate’s use,few data on the effect of alendronate during epiphyseal growth exist.AIM Verify the effect of alendronate on the growth epiphyseal plate,and compare its effect with the size of the femur during the double-staining of the immunolocalization of transforming growth factor-β1(TGF-β1)and bone morphogenetic protein-2(BMP2)in endochondral ossifing in specimens that have received alendronate.METHODS Forty newborn rats were randomly divided into two groups:a control group(were given applications of 1 mg/kg physiologic saline)and a group that received Alendronate(a dose of 2.5 mg/kg).These groups were then divided into two subgroups for euthanasia in two and 12 d of life.After euthanasia,the femurs were removed,and the femoral bones were measured linearly between the apex of the greater trochanter until the lower intercondylar midlle face to verify the probable bone growth between 3 and 12 d in control and alednroanto treated rats.Posteriorly,the surgical pieces were also sent to the histopathology laboratory to produce histological slides.The obtained slides were stained with hematoxylin and eosin to measure each of the cartilage zones in endochondral development.and other slides were immunohistochemically tested for anti-TGF-β1 and BMP-2 antibodies to investigate the immunolocalization of these proteins in the epiphyseal plaque area.RESULTS On the third day,some diferences between the control group and specimens treated with alendronate were verified.Macroscopiccaly,we found similarities in size between the femoral bones when we compared the control group with the specimens that received alendronate.On the 12^th day,the bone size of the mice receiving the drug was significantly smaller than those of the control group.These results coincide with changes in the TGF-β1 and BMP-2 expression.In the specimens that received alendronate,the TGF-β1 was expressed in some sites of trabecular bone that was neoformed,peripherally to the bone marrow area.The BMP-2 was also positive in proliferative chondrocytes and hypertrofic chondrocytes.On the 12^th day,all layers of chondrocytes exhibited positivity for BMP-2 in the specimens that received alendronate.In the interface between the trabecular bone and cartilage,an area of disorganized bone deposition was evident.Neoformed bone also appeared to be different at 12 d.In the control group,BMP-2 was positive in an intense area of bone trabeculae,whereas the alendronate-treated group showed TGF-β1 positive trabeculae and a greater bone area.CONCLUSION Alendronate alters the immunolocalization of TGF-β1 and BMP-2 simultaneously,a condition that changes the usual histological aspects of the cartilage zone and impairs epiphysis growth and femur growth.展开更多
Background： Fibroblast growth factor receptor 3 （FGFR3） inhibits growth-plate chondrocyte proliferation and limits bone elongation. Gain-of-function FGFR3 mutations cause dwarfism, reduced telomerase activity and s...Background： Fibroblast growth factor receptor 3 （FGFR3） inhibits growth-plate chondrocyte proliferation and limits bone elongation. Gain-of-function FGFR3 mutations cause dwarfism, reduced telomerase activity and shorter telomeres in growth plate chondroyctes suggesting that FGFR3 reduces proliferative capacity, inhibits telomerase, and enhances senescence. Thyroid hormone （1-3） plays a role in cellular maturation of growth plate chondrocytes and a known target of T3 is FGFR3. The present study addressed whether reduced FGFR3 expression enhanced telomerase activity, mRNA expression of telomerase reverse transcriptase （TERT） and RNA component of telomerase （TR）, and chondrocyte proliferation, and whether the stimulation of FGFR3 by T3 evoked the opposite response. Results： Sheep growth-plate proliferative zone chondrocytes were cultured and transfected with siRNA to reduce FGFR3 expression; FGFR3 siRNA reduced chondrocyte FGFR3 mRNA and protein resulting in greater proliferation and increased TERT mRNA expression and telomerase activity （p 〈 0.0.5）. Chondrocytes treated with T3 significantly enhanced FGFR3 mRNA and protein expression and reduced telomerase activity （p 〈 0.05）; TERT and TR were not significantly reduced. The action of T3 at the growth plate may be partially mediated through the FGFR3 pathway. Conclusions： The results suggest that FGFR3 inhibits chondrocyte proliferation and reducing telomerase activity indicating an important role for telomerase in capacity during bone elongation. by down-regulating TERT expression sustaining chondrocyte proliferative展开更多
The 6061-T651 aluminium alloy is one of the most common aluminium alloys for marine components and general structures. The stress intensity factor (SIF) is an important parameter for estimating the life of the cracked...The 6061-T651 aluminium alloy is one of the most common aluminium alloys for marine components and general structures. The stress intensity factor (SIF) is an important parameter for estimating the life of the cracked structure. In this paper, the stress intensity factors of a slant-cracked plate, which is made of 6061-T651 aluminum, have been calculated using extended finite element method (XFEM) and finite element method (FEM) in ABAQUS software and the results were compared with theoretical values. Numerical values obtained from these two methods were close to the theoretical values. In simulations of crack growth at different crack angles, the crack propagation angle values were closer to the theoretical values in XFEM method. Also, the accuracy and validity of fatigue crack growth curve were much closer to the theoretical graph in XFEM than the FEM. Therefore, in this paper the capabilities of XFEM were realized in analyzing issues such as cracks.展开更多
In the classical microbial isolation technique,the isolation process inevitably destroys all microbial interactions and thus makes it difficult to culture the many microorganisms that rely on these interactions for su...In the classical microbial isolation technique,the isolation process inevitably destroys all microbial interactions and thus makes it difficult to culture the many microorganisms that rely on these interactions for survival.In this study,we designed a simple coculture technique named the“sandwich agar plate method,”which maintains microbial interactions throughout the isolation and pure culture processes.The total yield of uncultured species in sandwich agar plates based on eight helper strains was almost 10-fold that of the control group.Many uncultured species displayed commensal lifestyles.Further study found that heme was the growth-promoting factor of some marine commensal bacteria.Subsequent genomic analysis revealed that heme auxotrophies were common in various biotopes and prevalent in many uncultured microbial taxa.Moreover,our study supported that the survival strategies of heme auxotrophy in different habitats varied considerably.These findings highlight that cocultivation based on the“sandwich agar plate method”could be developed and used to isolate more uncultured bacteria.展开更多
文摘BACKGROUND The epiphyseal growth plate is an important anatomical segment localized on the ends of a long bone.Despite the abovementioned atractive reasons for alendronate’s use,few data on the effect of alendronate during epiphyseal growth exist.AIM Verify the effect of alendronate on the growth epiphyseal plate,and compare its effect with the size of the femur during the double-staining of the immunolocalization of transforming growth factor-β1(TGF-β1)and bone morphogenetic protein-2(BMP2)in endochondral ossifing in specimens that have received alendronate.METHODS Forty newborn rats were randomly divided into two groups:a control group(were given applications of 1 mg/kg physiologic saline)and a group that received Alendronate(a dose of 2.5 mg/kg).These groups were then divided into two subgroups for euthanasia in two and 12 d of life.After euthanasia,the femurs were removed,and the femoral bones were measured linearly between the apex of the greater trochanter until the lower intercondylar midlle face to verify the probable bone growth between 3 and 12 d in control and alednroanto treated rats.Posteriorly,the surgical pieces were also sent to the histopathology laboratory to produce histological slides.The obtained slides were stained with hematoxylin and eosin to measure each of the cartilage zones in endochondral development.and other slides were immunohistochemically tested for anti-TGF-β1 and BMP-2 antibodies to investigate the immunolocalization of these proteins in the epiphyseal plaque area.RESULTS On the third day,some diferences between the control group and specimens treated with alendronate were verified.Macroscopiccaly,we found similarities in size between the femoral bones when we compared the control group with the specimens that received alendronate.On the 12^th day,the bone size of the mice receiving the drug was significantly smaller than those of the control group.These results coincide with changes in the TGF-β1 and BMP-2 expression.In the specimens that received alendronate,the TGF-β1 was expressed in some sites of trabecular bone that was neoformed,peripherally to the bone marrow area.The BMP-2 was also positive in proliferative chondrocytes and hypertrofic chondrocytes.On the 12^th day,all layers of chondrocytes exhibited positivity for BMP-2 in the specimens that received alendronate.In the interface between the trabecular bone and cartilage,an area of disorganized bone deposition was evident.Neoformed bone also appeared to be different at 12 d.In the control group,BMP-2 was positive in an intense area of bone trabeculae,whereas the alendronate-treated group showed TGF-β1 positive trabeculae and a greater bone area.CONCLUSION Alendronate alters the immunolocalization of TGF-β1 and BMP-2 simultaneously,a condition that changes the usual histological aspects of the cartilage zone and impairs epiphysis growth and femur growth.
基金supported by W.K. Kellogg Endowmentthe infrastructure support of the Department of Animal Science, College of Agricultural and Environmental Sciences+1 种基金the California Agricultural Experiment Station of the University of California-Davis(CA-D*-ASC-5256-AH)financial assistance from Scholarships funded by the Ford Family Foundation and the endowment of G. Kirk Swingle
文摘Background： Fibroblast growth factor receptor 3 （FGFR3） inhibits growth-plate chondrocyte proliferation and limits bone elongation. Gain-of-function FGFR3 mutations cause dwarfism, reduced telomerase activity and shorter telomeres in growth plate chondroyctes suggesting that FGFR3 reduces proliferative capacity, inhibits telomerase, and enhances senescence. Thyroid hormone （1-3） plays a role in cellular maturation of growth plate chondrocytes and a known target of T3 is FGFR3. The present study addressed whether reduced FGFR3 expression enhanced telomerase activity, mRNA expression of telomerase reverse transcriptase （TERT） and RNA component of telomerase （TR）, and chondrocyte proliferation, and whether the stimulation of FGFR3 by T3 evoked the opposite response. Results： Sheep growth-plate proliferative zone chondrocytes were cultured and transfected with siRNA to reduce FGFR3 expression; FGFR3 siRNA reduced chondrocyte FGFR3 mRNA and protein resulting in greater proliferation and increased TERT mRNA expression and telomerase activity （p 〈 0.0.5）. Chondrocytes treated with T3 significantly enhanced FGFR3 mRNA and protein expression and reduced telomerase activity （p 〈 0.05）; TERT and TR were not significantly reduced. The action of T3 at the growth plate may be partially mediated through the FGFR3 pathway. Conclusions： The results suggest that FGFR3 inhibits chondrocyte proliferation and reducing telomerase activity indicating an important role for telomerase in capacity during bone elongation. by down-regulating TERT expression sustaining chondrocyte proliferative
文摘The 6061-T651 aluminium alloy is one of the most common aluminium alloys for marine components and general structures. The stress intensity factor (SIF) is an important parameter for estimating the life of the cracked structure. In this paper, the stress intensity factors of a slant-cracked plate, which is made of 6061-T651 aluminum, have been calculated using extended finite element method (XFEM) and finite element method (FEM) in ABAQUS software and the results were compared with theoretical values. Numerical values obtained from these two methods were close to the theoretical values. In simulations of crack growth at different crack angles, the crack propagation angle values were closer to the theoretical values in XFEM method. Also, the accuracy and validity of fatigue crack growth curve were much closer to the theoretical graph in XFEM than the FEM. Therefore, in this paper the capabilities of XFEM were realized in analyzing issues such as cracks.
基金supported by the National Natural Science Foundation of China(Nos.32070002 and 41876166)Science&Technology Fundamental Resources Investigation Program(Grant Nos.2022FY101100 and 2019FY100700)+1 种基金China Postdoctoral Science Foundation(2022M721923)Natural Science Foundation of Shandong Province,China(ZR2023QD187).
文摘In the classical microbial isolation technique,the isolation process inevitably destroys all microbial interactions and thus makes it difficult to culture the many microorganisms that rely on these interactions for survival.In this study,we designed a simple coculture technique named the“sandwich agar plate method,”which maintains microbial interactions throughout the isolation and pure culture processes.The total yield of uncultured species in sandwich agar plates based on eight helper strains was almost 10-fold that of the control group.Many uncultured species displayed commensal lifestyles.Further study found that heme was the growth-promoting factor of some marine commensal bacteria.Subsequent genomic analysis revealed that heme auxotrophies were common in various biotopes and prevalent in many uncultured microbial taxa.Moreover,our study supported that the survival strategies of heme auxotrophy in different habitats varied considerably.These findings highlight that cocultivation based on the“sandwich agar plate method”could be developed and used to isolate more uncultured bacteria.
