Waning immune responses against SARS-CoV-2 among vaccinees in Hong Kong

BackgroundNearly 4 billion doses of the BioNTech-mRNA and Sinovac-inactivated vaccines have been administrated globally, yet different vaccine-induced immunity against SARS-CoV-2 variants of concern (VOCs) remain incompletely investigated. MethodsWe compare the immunogenicity and durability of these two vaccines among fully vaccinated Hong Kong people. FindingsStandard BioNTech and Sinovac vaccinations were tolerated and induced neutralizing antibody (NAb) (100% and 85.7%) and spike-specific CD4 T cell responses (96.7% and 82.1%), respectively. The geometric mean NAb IC50 and median frequencies of reactive CD4 subsets were consistently lower among Sinovac-vaccinees than BioNTech-vaccinees. Against VOCs, NAb response rate and geometric mean IC50 against B1.351 and B.1.617.2 were significantly lower for Sinovac (14.3%, 15 and 50%, 23.2) than BioNTech (79.4%, 107 and 94.1%, 131). Three months after vaccinations, NAbs to VOCs dropped near to detection limit, along with waning memory T cell responses, mainly among Sinovac-vaccinees. InterpretationOur results indicate that Sinovac-vaccinees may face higher risk to pandemic VOCs breakthrough infection. FundingThis study was supported by the Hong Kong Research Grants Council Collaborative Research Fund (C7156-20GF to Z.C and C1134-20GF); the National Program on Key Research Project of China (Grant 2020YFC0860600, 2020YFA0707500 and 2020YFA0707504); Shenzhen Science and Technology Program (JSGG20200225151410198 and JCYJ20210324131610027); HKU Development Fund and LKS Faculty of Medicine Matching Fund to AIDS Institute; Hong Kong Innovation and Technology Fund, Innovation and Technology Commission and generous donation from the Friends of Hope Education Fund. Z.C.s team was also partly supported by the Theme-Based Research Scheme (T11-706/18-N).

The evolutionarily conserved gene, Fam114a2, is dispensable for fertility in mouse.

Family with sequence similarity 114 member A2 (Fam114a2) is sperm binding protein that is highly conserved in mammals with homologs both in fungi and plants. Previous studies have demonstrated that miR-762 and P63 are two crucial players of spermatogenesis, and CricFM114A2 regulates their expression. Thus, the current study was focused on describing the role of Fam114a2 in spermatogenesis by generating Fam114a2 knockout (Fam114a2-/-) mice using CRISPR/Cas9 genome editing techniques. We identified that Fam114a2-/- mouse has normal fertility and normal morphology of sperm. Furthermore, histological investigation of testicular and epididymis tissues showed no subtle difference, and seminiferous tubules comprised of all stages of germ cells, including mature spermatozoa in Fam114a2-/- mice. Moreover, cytological investigation of spermatocytes in the progression of prophase I also did not display any notable difference in Fam114a2-/- mice. Additionally, normal expression of p63 and miR-762 was observed in Fam114a2+/+ and Fam114a2-/- testis indicating that Fam114a2 is not involved in the direct regulation of in mice spermatogenesis. Moreover, the removal of Fam114a2 in mouse did not affect the expression of its paralogue Fam114a1 in multiple tissues. Taken together our data determined that Fam114a2 is not essential for male fertility and spermatogenesis in mice.

Anatomical characters of the proximal tibial osteotomy in healthy Mongolia populations / 中国组织工程研究

BACKGROUND: Whether the proximal tibial osteotomy in Mongolia populations has difference with other populations at home and abroad remains unclear.OBJECTIVE: To analyze the anatomical characters of the proximal tibial osteotomy in Mongolia populations in the northern region of China by measuring the relevant linear parameters.METHODS: Thirty-eight healthy Mongolia populations were selected, and their bilateral knee joints were scanned by CT.The original data were exported in DICOM format. Mimics software was used to reconstruct the knee three-dimensional model. The tibial data stored in STL format were imported into 3-matic software, showing the medial surface of the tibia,and 6 mm below the medial tibial plateau maintaining 7° posterior slop was subjected to total hip arthroplasty osteotomy.Subsequently, the relevant parameters were measured.RESULTS AND CONCLUSION: (1) The left tibia transverse diameter was (79.99±3.70) mm, and the right was (80.25±4.01) mm. The left anteroposterior diameter was (52.27±3.07) mm, and the right was (51.75±2.40) mm. The anteroposterior diameter of medial tibia was (55.40±2.00) mm (left), and (56.67±2.47) mm (right); the lateral was (49.84±2.78) mm (left), and (49.58±2.80) mm (right). (2) In Mongolian populations, the linear parameters showed no significant differences between two sides of the proximal tibial osteotomy (P > 0.05). The anteroposterior diameter of medial tibia was longer than that of lateral one (P > 0.05). The linear parameters of the proximal tibial osteotomy in male were significantly larger than those in female (P < 0.05). There were differences in the linear parameters of the proximal tibial osteotomy between Mongolian populations and other populations. (3)These results indicate that there are significant differences in the anatomical morphology of the tibial plateau between western and eastern countries.Besides, the geometric parameters of the tibial plateau may be different in different ethnic groups and regions. It is necessary to use the digital orthopedic technique to investigate and analyze the large sample data of different ethnic groups in different regions.

Posterior slope angle of the tibial plateau in 60 healthy Mongolia population measured by computed tomography / 中国组织工程研究

BACKGROUND: There are more measurement data about knee joint at home and abroad, but few data about the northern China, especially Inner Mongolia region. Whether the posterior slope angle of tibial plateau in local area differs from that of Chinese or foreigners is rarely reported.OBJECTIVE: To measure the posterior slope angle of the medial tibial plateau in healthy Mongolia population, and to compare the differences of different measurement methods, so as to understand the anatomical characters of tibial plateau in Inner Mongolia region.METHODS: Sixty Mongolian volunteers were recruited, the 20 cm upper and under the knee joint were scanned bilaterally by GE64 row spiral CT, and the three-dimensional model of the knee was established on Mimics16.0 software, followed by processed through fairing, filling, separation and cutting. Afterwards, the angel between anterior cortical bone extension line of upper tibia (method A), tibia anatomical axis (method B), line perpendicular to the posterior cortical bone extension line of upper tibia (method C) and upper edge line of the tibial plateau was measured,respectively. The posterior slope angle of the medial tibial plateau (90°-measured angle) was obtained and compared.RESULTS AND CONCLUSION: (1) The posterior slope angle of the medial tibial plateau measured by methods A, B and C was (11.16±3.39)°, (8.60±3.29)° and (5.30±4.40)°, respectively, and the former two were similar with those reported by Wang Ye-hua and Luo Ji-wei (P > 0.05). (2) There were significant differences in the posterior slope angle of the left and right medial tibial plateau among methods (P 0.05). (3) There was no significant difference in the posterior slope angle of the left and right medial tibial plateau between genders (P > 0.05). (4) These results indicate that the Mongolian population show smaller posterior slope angle of the tibial plateau, but the angle exhibits great individual difference, thereafter, an individualize scheme should be developed before osteotomy.

Application and safety of tranexamic acid in total knee arthroplasty / 中国组织工程研究

BACKGROUND:Studies suggested that blood loss was great during total knee arthroplasty, even blood transfusion was needed. Application of the tourniquet wil destroy the coagulation system, and is not conducive to hemostasis after replacement. Recently, tranexamic acid has been extensively used to reduce blood loss during total knee arthroplasty, because of low price, simple administration pathway, and effective effects on hemostasis. OBJECTIVE:To summarize the application and safety of tranexamic acid in total knee arthroplasty. METHODS:The first author retrieved PubMed and Chinese Journal Ful Text Database for articles from inception to October 2015. The key words were tranexamic acid, total knee arthroplasty, hemorrhage. More than 200 articles were retrieved, and finaly 50 articles met the inclusion criteria. RESULTS AND CONCLUSION:Tranexamic acid is a fibrinolytic inhibitor, can reversibly block the binding of plasminogen to fibrin, effectively inhibit fibrinolysis, and reduce hemorrhage after total knee arthroplasty. Nevertheless, there were significant differences in the use, dose and effect of tranexamic acid on hemostasis among different studies. Tranexamic acid was an effective drug for hemostasis during total knee arthroplasty. During total knee arthroplasty, tranexamic acid had been used to reduce dominant blood loss and hidden blood loss after arthroplasty, and could not increase the risk for venous thrombosis of lower limb. Currently, the timing of use, dosage, route of administration, and possible complications of tranexamic acid remain controversial.

Replantation of inactivated tumor segment boiled in 70℃ distilled water for 15 minutes in the treatment of proximal fibular tumors / 中国组织工程研究

BACKGROUND:Apart from a complete resection of tumor tissues, the therapeutic goal for bone tumors is to maximize the repair and restoration of tissue defects and damaged functions. Autologous inactivated bone graft is of practical value for transplantation and reconstruction. OBJECTIVE:To investigate the effect of improved Malawer method combined with replantation of inactivated tumor segment in the treatment of proximal fibular tumors. METHODS: Since 2007, five patients with proximal fibular tumors (six sides) were admitted in the Affiliated Hospital of Inner Mongolia Medical University. These five patients were subjected to distal femoral amputation, intralesional curettage and bone grafting, upper fibular osteotomy + tumor segment heating (boiling in 70℃ distiled water for 15 minutes) + inactivated bone replantation. Therapeutic effects were folowed. RESULTS AND CONCLUSION: One case of amputation had no recurrence and systemic metastasis during 4 years of folow-up; one case of intralesional curettage and bone grafting relapsed 1 year after operation; three cases of upper fibular osteotomy + tumor segment heating + inactivated bone replantation folowed for 5 months recovered walking function and exhibited good healing of the outer structure of the knee, showing non-healing of inactivated tumor segment, non-remarkable calus formation, no local tumor recurrence, no loosening of internal fixation, and inactivated bone without fracture and absorption. These results confirmed that the tumor curettage and amputation both have obvious limitations; based on Malawer method, the replantation of inactive tumor segment can better ensure the structure integrity of the lower leg and in suit reconstruct the lateral biceps femoris tendon and the lateral colateral ligament, but geneticaly the revascularization and healing of inactivated bones wil be difficult and slow with temperature increases, and therefore the period of postoperative brace protection should be relatively extended, alowing time delay of strenuous exercise and avoiding complications such as fractures.