Objective To provide accurate bone tunnel positioning reference for clinical individual anterior cruciate ligament (ACL) reconstruction by three-dimensional (3D) reconstruction of femoral and tibial original footprint of ACL.Methods Forty volunteers were selected for this study,including 20 males and 20 females,and aged 18 to 35 years old.3D CT scanning images of knee data were obtained.3D bone models of knee and footprint of ACL were reconstructed.On the 3D reconstruction models,the shape and position of original footprint of ACL were displayed.Statistical significance was compared for their difference.Results Femoral original footprint of ACL,long axis of footprint,distances to the distal margin of the articular cartilage (DDCM),distances to the posterior margin of the articular cartilage (DPCM),double bundle center distance,and tibial original footprint short axis of ACL were significantly different between genders (P ＜ 0.05).However,no significant difference was found between genders for tibial original footprint long axis of ACL (P ＞ 0.05).Conclusions The insertion mark shape and nature position of footprint of ACL could be observed by 3D reconstruction using CT scan images.

Objective To discuss the characteristics,growth and development of atlantoaxial pedicle in preschool children,and to provide the basic theoretical basis for the design,production and clinical application of pedicle screw technique in the treatment of atlantoaxial disease in preschool children.Methods Excluded patients with atlantoaxial fractures,deformities,tuberculosis and tumor,the clinical data of 60 children aged from 3 to 6 years old with cervical spondylolisthesis were collected.The original CT images were reconstructed in DICOM format and the subjects were reconstructed with Mimics software.The subjects were grouped by age to measure and analyze the atlantoaxial pedicle correlation.Results The pedicle width(PW),pedicle height(PH) and total length of pedicle bone channel (PL) increased gradually with age.The PW/PH ratio of the vertebrae(C1) is greater than 1.0,and that is, the width of the pedicle of the C1 pedicle is greater than the height.The PW/PH ratio of the vertebral (C2) is less than 1.0,which means the width of the pedicle of the C1 pedicle is less than the height.Conclusion The growth and development of spine in preschool children are fast, and the pedicle of atlantoaxial calculus in different age groups has different developmental characteristics.In this study,the diameter of the pedicle of the atlantoaxial pedicle in the 3 to 6 year old children is increasing with age.The pedicle screw with the smallest diameter of 3.5 mm can be implanted into the atlantoaxial pedicle with feasibility in theory.

Medium spiny neurons (MSNs) in the striatum, which can be divided into D1 and D2 MSNs, originate from the lateral ganglionic eminence (LGE). Previously, we reported that Six3 is a downstream target of Sp8/Sp9 in the transcriptional regulatory cascade of D2 MSN development and that conditionally knocking out Six3 leads to a severe loss of D2 MSNs. Here, we showed that Six3 mainly functions in D2 MSN precursor cells and gradually loses its function as D2 MSNs mature. Conditional deletion of Six3 had little effect on cell proliferation but blocked the differentiation of D2 MSN precursor cells. In addition, conditional overexpression of Six3 promoted the differentiation of precursor cells in the LGE. We measured an increase of apoptosis in the postnatal striatum of conditional Six3-knockout mice. This suggests that, in the absence of Six3, abnormally differentiated D2 MSNs are eliminated by programmed cell death. These results further identify Six3 as an important regulatory element during D2 MSN differentiation.

Mouse cortical radial glial cells (RGCs) are primary neural stem cells that give rise to cortical oligodendrocytes, astrocytes, and olfactory bulb (OB) GABAergic interneurons in late embryogenesis. There are fundamental gaps in understanding how these diverse cell subtypes are generated. Here, by combining single-cell RNA-Seq with intersectional lineage analyses, we show that beginning at around E16.5, neocortical RGCs start to generate ASCL1