BACKGROUND:Condylar prosthesis replacement,as one of the surgical methods for the treatment of temporomandibular joint diseases,not only needs to restore the morphology and function,but also needs to ensure long-term stable application.OBJECTIVE:To design finite element analysis of a customized Gyroid condylar prosthesis.METHODS:Gyroid structure specimens with different wall thicknesses(250,350,450,550,650,and 750 μm)were designed by software.Finite element simulation compression experiments were carried out to test the elastic modulus of the specimens.The Gyroid structure wall thickness range that matches the elastic modulus of mandibular cancellous bone and whose pore size meets the osteogenesis conditions was screened out.This range was subdivided and Gyroid structure specimens were made using 3D printing technology.Mechanical compression experiments were carried out on a universal testing machine.The Gyroid structure wall thickness that meets the mechanical properties of mandibular bone,has an easier osteogenesis and a smaller strength was screened out by elastic modulus and compressive strength,and subsequent experiments were carried out.A three-dimensional model of a customized Gyroid condylar prosthesis was designed,and the finite element analysis of the blade jaw position and cusp interdigitation position of the model under natural occlusion was simulated.RESULTS AND CONCLUSION:(1)Finite element analysis results showed that with the increase of wall thickness,the elastic modulus of Gyroid structure specimens increased.The elastic modulus of Gyroid structure specimens with wall thickness of 350,450,550,650,and 750 μm matched the elastic modulus of mandibular cancellous bone.Since the subsequent experiments needed to be subdivided into groups and the pore size of the 550,650,and 750 μm wall thickness group(pore size 800-1 000 μm)was within the osteogenesis range.Gyroid structure specimens with wall thickness of 550,600,650,700,and 750μm were selected for mechanical compression experiments on a universal testing machine.(2)The results of mechanical compression experiments showed that with the increase of wall thickness,the elastic modulus and compressive strength of Gyroid structure specimens increased.The elastic modulus of Gyroid structure specimens with wall thickness of 550,600,and 650 μm was within the elastic modulus of the mandibular cancellous bone.Finally,the wall thickness of 650 μm and the pore size of 900 μm were selected to construct the three-dimensional model of the mandibular customized Gyroid condylar prosthesis.(3)The results of finite element analysis of three-dimensional model of the mandibular customized Gyroid condylar prosthesis showed that the stress of the articular disc in the edge-to-edge occlusion was mainly concentrated on the lower surface of the anterior middle band,and the stress of the articular disc in the interposition of tooth tips was mainly concentrated on the lateral surface of the lower surface.The maximum displacement and the maximum equivalent stress of the left and right articular discs in the edge-to-edge occlusion and the interposition of tooth tips were similar.The maximum displacement was 0.031,0.030,0.028,and 0.018 mm,and the maximum equivalent stress was 2.87,2.30,2.73,and 1.71 MPa,respectively.(4)The results showed that the Gyroid structure with a wall thickness of 650 μm was consistent with the mechanical properties of the mandible,which reduced the strength of the titanium alloy and reduced the damage of the articular disc caused by the customized Gyroid condylar prosthesis.

OBJECTIVE: To assess the feasibility of first polar body transfer (PB1T) combined with preimplantation mitochondrial genetic testing for blocking the transmission of a pathogenic mitochondrial DNA 8993T>G mutation. METHODS: A Chinese family affected with Leigh syndrome which had attended the Reproductive Medicine Centre of the First Affiliated Hospital of Anhui Medical University in September 2021 was selected as the study subject. Controlled ovarian hyperstimulation was carried out for the proband after completing the detection of the mitochondrial DNA 8993T>G mutation load among the pedigree members. Mature MII oocytes were inseminated by intracytoplasmic sperm injection (ICSI), cultured in vitro for 5 to 6 days to the blastocyst stage, and trophoblastocytes were obtained by microbiopsy. Mitochondrial DNA testing (PGT-MT) and chromosomal aneuploidy (PGT-A) analyses were carried out after whole-genome amplification, and the embryos with zero mutation load were selected for transfer. Amniotic fluid and umbilical cord blood samples were collected during middle pregnancy and after birth respectively for mitochondrial DNA testing to verify the reliability of embryo screening. As an attempt, PB1 with good morphology of MII oocytes was selected for transfer into the enucleated oocytoplasm from healthy donors, followed by ICSI fertilization, blastocyst culture and PGT of embryos using the same procedure. This study has been approved by the Ethics Committee of the First Affiliated Hospital of Anhui Medical University (No. 2021zhyx-B12). RESULTS: An antagonist protocol was used for ovarian stimulation, and a total of 19 oocytes were obtained, of which 14 MII were fertilized by ICSI, and 2 had developed into blastocysts. PGT-MT was carried out on biopsied trophoblastocytes, in which the mitochondrial DNA 8993T>G mutation load was not detected in one embryo, the other was 100% mutated, and the mutation loads of the remaining unfertilized eggs and developmentally arrested embryos ranged from 0% ~ 100%, presenting a clear biased distribution. With fully informed consent, one PGT-MT zero mutation load blastocyst was transferred and clinical pregnancy was achieved. Mitochondrial DNA and chromosomal testing of amniotic fluid cells during middle pregnancy had revealed no abnormalities. The proband had delivered a healthy boy through Caesarean section at 39⁺⁵ weeks of gestation, and no mutation was detected in the cord blood sample. Five well-formed PBs from 14 eggs were selected for PB1 transfer, followed by ICSI and culture, and two of the reconstituted embryos had formed blastocysts, with none of the above mutations detected in the biopsied samples. CONCLUSION The PGT-MT technology can help families affected with mitochondrial diseases to have healthy offspring. PB1 transfer in combination with ICSI and PGT-MT holds the promise of turning waste into treasure and providing an alternative means of fertility for such families.
Humans ; Preimplantation Diagnosis/methods* ; Female ; DNA, Mitochondrial/genetics* ; Genetic Testing/methods* ; Pregnancy ; Mitochondrial Diseases/genetics* ; Polar Bodies ; Adult ; Feasibility Studies ; Sperm Injections, Intracytoplasmic/methods* ; Embryo Transfer/methods* ; Mutation ; Male ; Blastocyst/metabolism* ; Pedigree

Objective:To assess the feasibility of first polar body transfer (PB1T) combined with preimplantation mitochondrial genetic testing for blocking the transmission of a pathogenic mitochondrial DNA 8993T>G mutation.Methods:A Chinese family affected with Leigh syndrome which had attended the Reproductive Medicine Centre of the First Affiliated Hospital of Anhui Medical University in September 2021 was selected as the study subject. Controlled ovarian hyperstimulation was carried out for the proband after completing the detection of the mitochondrial DNA 8993T>G mutation load among the pedigree members. Mature MII oocytes were inseminated by intracytoplasmic sperm injection (ICSI), cultured in vitro for 5 to 6 days to the blastocyst stage, and trophoblastocytes were obtained by microbiopsy. Mitochondrial DNA testing (PGT-MT) and chromosomal aneuploidy (PGT-A) analyses were carried out after whole-genome amplification, and the embryos with zero mutation load were selected for transfer. Amniotic fluid and umbilical cord blood samples were collected during middle pregnancy and after birth respectively for mitochondrial DNA testing to verify the reliability of embryo screening. As an attempt, PB1 with good morphology of MⅡ oocytes was selected for transfer into the enucleated oocytoplasm from healthy donors, followed by ICSI fertilization, blastocyst culture and PGT of embryos using the same procedure. This study has been approved by the Ethics Committee of the First Affiliated Hospital of Anhui Medical University (No. 2021zhyx-B12). Results:An antagonist protocol was used for ovarian stimulation, and a total of 19 oocytes were obtained, of which 14 MⅡ were fertilized by ICSI, and 2 had developed into blastocysts. PGT-MT was carried out on biopsied trophoblastocytes, in which the mitochondrial DNA 8993T>G mutation load was not detected in one embryo, the other was 100% mutated, and the mutation loads of the remaining unfertilized eggs and developmentally arrested embryos ranged from 0% ~ 100%, presenting a clear biased distribution. With fully informed consent, one PGT-MT zero mutation load blastocyst was transferred and clinical pregnancy was achieved. Mitochondrial DNA and chromosomal testing of amniotic fluid cells during middle pregnancy had revealed no abnormalities. The proband had delivered a healthy boy through Caesarean section at 39+ 5 weeks of gestation, and no mutation was detected in the cord blood sample. Five well-formed PBs from 14 eggs were selected for PB1 transfer, followed by ICSI and culture, and two of the reconstituted embryos had formed blastocysts, with none of the above mutations detected in the biopsied samples.Conclusion:The PGT-MT technology can help families affected with mitochondrial diseases to have healthy offspring. PB1 transfer in combination with ICSI and PGT-MT holds the promise of turning waste into treasure and providing an alternative means of fertility for such families.

Objective:To identify the trajectories of dietary choline intake in middle-aged and older population, and to analyze its longitudinal association with cognitive function.Methods:Subjects aged 55 to 79 years with at least two rounds of completed population economics, lifestyle, disease history, cognitive function, dietary assessments and physical measurements in 1997-2018 and those with at least three rounds of dietary measures in 1991-2015 were selected from the China Health and Nutrition Survey. Dietary survey was conducted using three consecutive 24-hour dietary recalls combined with a weighing inventory at the household level. Cognitive assessment was performed using part of the Telephone Interview for Cognitive Status Scale. Group-based univariate trajectory modeling was used to identify trajectory of choline intake, and three-level linear mixed-effects models or three-level logistic mixed-effects models was employed to analyze the relationship between trajectory groups and cognitive function. Subgroup analyses were conducted by gender and age at baseline.Results:Four trajectories of dietary choline intake were identified in the whole population, named as low-intake-stable group (61.0%), medium-intake-stable group (23.9%), medium-intake-slowly-declined group (11.2%), and high-intake-stable group (3.9%). Three trajectories were identified for each subgroup. Low-intake-stable group accounted for more than 60% in total population as well as each subgroup, especially in women and 55-59 years group. After adjusting for covariates, global cognitive scores were 0.54 (95% CI: 0.26-0.82), 0.77 (95% CI: 0.36-1.18), and 0.85 (95% CI: 0.21-1.48) points higher in medium-intake-stable, medium-intake- slowly-declined and high-intake-stable groups in the whole population, respectively, compared with the low-intake-stable group. The likelihoods of cognitive decline were 18.4% ( OR=0.816,95% CI: 0.709-0.939), 17.6% ( OR=0.824, 95% CI: 0.680-0.998), 24.4% ( OR=0.756, 95% CI: 0.589-0.970) and 22.4% ( OR=0.776,95% CI: 0.623-0.968) lower in medium-intake-stable group of dietary choline in the whole population, medium-intake-stable group in males, medium-intake-slightly-increased group in females and medium-intake-slowly-increased group in 55-59 years at baseline than in low-intake-stable group, respectively. Conclusions:Dietary choline intake is generally lower in the Chinese population aged 55-79 years. Long-term lower choline intake has a negative impact on cognitive function in middle-aged and older adults and may increase the risk of cognitive decline. The increment in the consumption of choline-enriched foods should be recommended.

BACKGROUND:Currently,the mandibular joint prosthesis manufactured at home and abroad needs to rely on screws to fix the condylar part of the prosthesis during the replacement process,and the retention hole is reserved to facilitate the operation during the operation.However,due to the lack of personalized jaw design,the reattachment plate may not fit the jaw,resulting in screw loosening and dislocation.Therefore,personalized condylar prosthesis replacement is of great value in the repair of the temporomandibular joint.OBJECTIVE:To design a personalized condylar prosthesis with an internal GYROID for mandibular condylar repair and reconstruction.METHODS:The GYROID structure was selected in the Rhinoceros 7 software with the single cell size of 6 mm and the wall thickness of 0.2,0.3,0.4,0.5,0.6,0.7,0.8 mm.The mechanical properties of the GYROID structure were analyzed by finite element method.3D printing of GYROID structural test specimens with different wall thickness(0.2,0.3,0.4,0.5,0.6,0.7,and 0.8 mm)was performed to test the mechanical properties of the specimens through room temperature compression experiments.A wall thickness value conforming to the range of mandibular mechanical properties was selected through finite element analysis and room temperature compression test results.An adult male mandibular CT data were used for inverse modeling to design a condylar prosthesis with an internal GYROID.Finite element analysis was used to simulate the movement of the apical staggered position and the opposite-blade jaw position after condylar prosthesis replacement.RESULTS AND CONCLUSION:(1)The results of finite element analysis and room temperature compression experiment showed that the elastic modulus of the GYROID structure increased with the increase of wall thickness.The elastic modulus of the GYROID structure with wall thickness of 0.5-0.7 mm was within the range of the elastic modulus of the mandible(1.5-4.0 GPa).Therefore,the 6 mm monocellular GYROID structural model with a wall thickness of 0.6 mm was selected for the design of the condylar prosthesis.(2)The results of finite element analysis showed that the stress distribution of mandibular model was symmetrical.The stress distribution of the two types of occlusion was roughly the same,and the stress peak was not significantly different.The stress concentrated in the neck of the condylar prosthesis,and the stress on the replacement side was slightly larger than that on the healthy side.The maximum equivalent stress of the whole internal fixation model was 269.34 MPa,and the maximum equivalent stress of the screw was 20.14 MPa.The equivalent stress and equivalent strain values of the prosthesis were greater than that of the opposite edge jaw position when the tooth tip was interlaced.The equivalent stress and equivalent strain values of the screw were smaller than that of the opposite edge jaw position when the tooth tip was interlaced.(3)The results showed that the design and retention of the personalized GYROID condylar prosthesis were good,which was consistent with the mechanical conduction of the mandible.

Objective:To identify the trajectories of dietary choline intake in middle-aged and older population, and to analyze its longitudinal association with cognitive function.Methods:Subjects aged 55 to 79 years with at least two rounds of completed population economics, lifestyle, disease history, cognitive function, dietary assessments and physical measurements in 1997-2018 and those with at least three rounds of dietary measures in 1991-2015 were selected from the China Health and Nutrition Survey. Dietary survey was conducted using three consecutive 24-hour dietary recalls combined with a weighing inventory at the household level. Cognitive assessment was performed using part of the Telephone Interview for Cognitive Status Scale. Group-based univariate trajectory modeling was used to identify trajectory of choline intake, and three-level linear mixed-effects models or three-level logistic mixed-effects models was employed to analyze the relationship between trajectory groups and cognitive function. Subgroup analyses were conducted by gender and age at baseline.Results:Four trajectories of dietary choline intake were identified in the whole population, named as low-intake-stable group (61.0%), medium-intake-stable group (23.9%), medium-intake-slowly-declined group (11.2%), and high-intake-stable group (3.9%). Three trajectories were identified for each subgroup. Low-intake-stable group accounted for more than 60% in total population as well as each subgroup, especially in women and 55-59 years group. After adjusting for covariates, global cognitive scores were 0.54 (95% CI: 0.26-0.82), 0.77 (95% CI: 0.36-1.18), and 0.85 (95% CI: 0.21-1.48) points higher in medium-intake-stable, medium-intake- slowly-declined and high-intake-stable groups in the whole population, respectively, compared with the low-intake-stable group. The likelihoods of cognitive decline were 18.4% ( OR=0.816,95% CI: 0.709-0.939), 17.6% ( OR=0.824, 95% CI: 0.680-0.998), 24.4% ( OR=0.756, 95% CI: 0.589-0.970) and 22.4% ( OR=0.776,95% CI: 0.623-0.968) lower in medium-intake-stable group of dietary choline in the whole population, medium-intake-stable group in males, medium-intake-slightly-increased group in females and medium-intake-slowly-increased group in 55-59 years at baseline than in low-intake-stable group, respectively. Conclusions:Dietary choline intake is generally lower in the Chinese population aged 55-79 years. Long-term lower choline intake has a negative impact on cognitive function in middle-aged and older adults and may increase the risk of cognitive decline. The increment in the consumption of choline-enriched foods should be recommended.

BACKGROUND:Condylar prosthesis replacement,as one of the surgical methods for the treatment of temporomandibular joint diseases,not only needs to restore the morphology and function,but also needs to ensure long-term stable application.OBJECTIVE:To design finite element analysis of a customized Gyroid condylar prosthesis.METHODS:Gyroid structure specimens with different wall thicknesses(250,350,450,550,650,and 750 μm)were designed by software.Finite element simulation compression experiments were carried out to test the elastic modulus of the specimens.The Gyroid structure wall thickness range that matches the elastic modulus of mandibular cancellous bone and whose pore size meets the osteogenesis conditions was screened out.This range was subdivided and Gyroid structure specimens were made using 3D printing technology.Mechanical compression experiments were carried out on a universal testing machine.The Gyroid structure wall thickness that meets the mechanical properties of mandibular bone,has an easier osteogenesis and a smaller strength was screened out by elastic modulus and compressive strength,and subsequent experiments were carried out.A three-dimensional model of a customized Gyroid condylar prosthesis was designed,and the finite element analysis of the blade jaw position and cusp interdigitation position of the model under natural occlusion was simulated.RESULTS AND CONCLUSION:(1)Finite element analysis results showed that with the increase of wall thickness,the elastic modulus of Gyroid structure specimens increased.The elastic modulus of Gyroid structure specimens with wall thickness of 350,450,550,650,and 750 μm matched the elastic modulus of mandibular cancellous bone.Since the subsequent experiments needed to be subdivided into groups and the pore size of the 550,650,and 750 μm wall thickness group(pore size 800-1 000 μm)was within the osteogenesis range.Gyroid structure specimens with wall thickness of 550,600,650,700,and 750μm were selected for mechanical compression experiments on a universal testing machine.(2)The results of mechanical compression experiments showed that with the increase of wall thickness,the elastic modulus and compressive strength of Gyroid structure specimens increased.The elastic modulus of Gyroid structure specimens with wall thickness of 550,600,and 650 μm was within the elastic modulus of the mandibular cancellous bone.Finally,the wall thickness of 650 μm and the pore size of 900 μm were selected to construct the three-dimensional model of the mandibular customized Gyroid condylar prosthesis.(3)The results of finite element analysis of three-dimensional model of the mandibular customized Gyroid condylar prosthesis showed that the stress of the articular disc in the edge-to-edge occlusion was mainly concentrated on the lower surface of the anterior middle band,and the stress of the articular disc in the interposition of tooth tips was mainly concentrated on the lateral surface of the lower surface.The maximum displacement and the maximum equivalent stress of the left and right articular discs in the edge-to-edge occlusion and the interposition of tooth tips were similar.The maximum displacement was 0.031,0.030,0.028,and 0.018 mm,and the maximum equivalent stress was 2.87,2.30,2.73,and 1.71 MPa,respectively.(4)The results showed that the Gyroid structure with a wall thickness of 650 μm was consistent with the mechanical properties of the mandible,which reduced the strength of the titanium alloy and reduced the damage of the articular disc caused by the customized Gyroid condylar prosthesis.

BACKGROUND:Currently,the mandibular joint prosthesis manufactured at home and abroad needs to rely on screws to fix the condylar part of the prosthesis during the replacement process,and the retention hole is reserved to facilitate the operation during the operation.However,due to the lack of personalized jaw design,the reattachment plate may not fit the jaw,resulting in screw loosening and dislocation.Therefore,personalized condylar prosthesis replacement is of great value in the repair of the temporomandibular joint.OBJECTIVE:To design a personalized condylar prosthesis with an internal GYROID for mandibular condylar repair and reconstruction.METHODS:The GYROID structure was selected in the Rhinoceros 7 software with the single cell size of 6 mm and the wall thickness of 0.2,0.3,0.4,0.5,0.6,0.7,0.8 mm.The mechanical properties of the GYROID structure were analyzed by finite element method.3D printing of GYROID structural test specimens with different wall thickness(0.2,0.3,0.4,0.5,0.6,0.7,and 0.8 mm)was performed to test the mechanical properties of the specimens through room temperature compression experiments.A wall thickness value conforming to the range of mandibular mechanical properties was selected through finite element analysis and room temperature compression test results.An adult male mandibular CT data were used for inverse modeling to design a condylar prosthesis with an internal GYROID.Finite element analysis was used to simulate the movement of the apical staggered position and the opposite-blade jaw position after condylar prosthesis replacement.RESULTS AND CONCLUSION:(1)The results of finite element analysis and room temperature compression experiment showed that the elastic modulus of the GYROID structure increased with the increase of wall thickness.The elastic modulus of the GYROID structure with wall thickness of 0.5-0.7 mm was within the range of the elastic modulus of the mandible(1.5-4.0 GPa).Therefore,the 6 mm monocellular GYROID structural model with a wall thickness of 0.6 mm was selected for the design of the condylar prosthesis.(2)The results of finite element analysis showed that the stress distribution of mandibular model was symmetrical.The stress distribution of the two types of occlusion was roughly the same,and the stress peak was not significantly different.The stress concentrated in the neck of the condylar prosthesis,and the stress on the replacement side was slightly larger than that on the healthy side.The maximum equivalent stress of the whole internal fixation model was 269.34 MPa,and the maximum equivalent stress of the screw was 20.14 MPa.The equivalent stress and equivalent strain values of the prosthesis were greater than that of the opposite edge jaw position when the tooth tip was interlaced.The equivalent stress and equivalent strain values of the screw were smaller than that of the opposite edge jaw position when the tooth tip was interlaced.(3)The results showed that the design and retention of the personalized GYROID condylar prosthesis were good,which was consistent with the mechanical conduction of the mandible.

Objective:To assess the feasibility of first polar body transfer (PB1T) combined with preimplantation mitochondrial genetic testing for blocking the transmission of a pathogenic mitochondrial DNA 8993T>G mutation.Methods:A Chinese family affected with Leigh syndrome which had attended the Reproductive Medicine Centre of the First Affiliated Hospital of Anhui Medical University in September 2021 was selected as the study subject. Controlled ovarian hyperstimulation was carried out for the proband after completing the detection of the mitochondrial DNA 8993T>G mutation load among the pedigree members. Mature MII oocytes were inseminated by intracytoplasmic sperm injection (ICSI), cultured in vitro for 5 to 6 days to the blastocyst stage, and trophoblastocytes were obtained by microbiopsy. Mitochondrial DNA testing (PGT-MT) and chromosomal aneuploidy (PGT-A) analyses were carried out after whole-genome amplification, and the embryos with zero mutation load were selected for transfer. Amniotic fluid and umbilical cord blood samples were collected during middle pregnancy and after birth respectively for mitochondrial DNA testing to verify the reliability of embryo screening. As an attempt, PB1 with good morphology of MⅡ oocytes was selected for transfer into the enucleated oocytoplasm from healthy donors, followed by ICSI fertilization, blastocyst culture and PGT of embryos using the same procedure. This study has been approved by the Ethics Committee of the First Affiliated Hospital of Anhui Medical University (No. 2021zhyx-B12). Results:An antagonist protocol was used for ovarian stimulation, and a total of 19 oocytes were obtained, of which 14 MⅡ were fertilized by ICSI, and 2 had developed into blastocysts. PGT-MT was carried out on biopsied trophoblastocytes, in which the mitochondrial DNA 8993T>G mutation load was not detected in one embryo, the other was 100% mutated, and the mutation loads of the remaining unfertilized eggs and developmentally arrested embryos ranged from 0% ~ 100%, presenting a clear biased distribution. With fully informed consent, one PGT-MT zero mutation load blastocyst was transferred and clinical pregnancy was achieved. Mitochondrial DNA and chromosomal testing of amniotic fluid cells during middle pregnancy had revealed no abnormalities. The proband had delivered a healthy boy through Caesarean section at 39+ 5 weeks of gestation, and no mutation was detected in the cord blood sample. Five well-formed PBs from 14 eggs were selected for PB1 transfer, followed by ICSI and culture, and two of the reconstituted embryos had formed blastocysts, with none of the above mutations detected in the biopsied samples.Conclusion:The PGT-MT technology can help families affected with mitochondrial diseases to have healthy offspring. PB1 transfer in combination with ICSI and PGT-MT holds the promise of turning waste into treasure and providing an alternative means of fertility for such families.

The steps for installation and withdrawal of WYD2000 field surgical lamp were introduced.The failures and causes of broken cross-arm connector of WYD2000 field surgical lamp were analyzed.The problems of WYD2000 field surgical lamp in vulnerability to breaking and difficulty in maintenance were solved by designing and manufacturing a special maintenance tool and optimizing the materials and fixing mode of cross-arm connection.References were provided for main-tenance and improvement of WYD2000 field surgical lamp.[Chinese Medical Equipment Journal,2024,45(4):116-118]