BACKGROUND:In an additional changing magnetic field, magnetosomes can invade the tumor cells and inhibit their proliferation.OBJECTIVE: To study the effect of targeted delivery of pHSP70-shPLK1/DOX compounds with magnetosome of magnetotactic bacteria on the treatment of osteosarcoma.METHODS: Human osteosarcoma cell U2OS was divided into four groups: group A: magnetosomes of magnetotactic bacteria+pHSP70-shPLK1/DOX complex; group B: magnetosomes of magnetotactic bacteria; group C: magnetosomes of magnetotactic bacteria+pHSP70-shPLK1/DOX complex, combined with magnetic intervention; group D: magnetosomes of magnetotactic bacteria, combined with magnetic intervention. After 12, 24, 48 and 72 hours of culture, the uptake rate of osteosarcoma cells was observed; cell cycle was evaluated by flow cytometry; PLK1 mRNA and protein expression levels were detected by RT-PCR and western blot, respectively; cell proliferation was explored by MTT assay; cell adhesion and invasion were checked by adhesion assay and Transwel chamber assay, respectively; and the apoptosis rate was measured by apoptosis detection Kit.RESULTS AND CONCLUSION: (1) After culture of 12 and 24 hours, the uptake rate was the highest in group D; meanwhile, the uptake rate was the highest in group B after 48 and 72 hours of culture. (2) The ratio of G2/M phase decreased and the ratio of G0/G1 increased gradualy in group A, group C and group D; the G2/M phase ratio of C group was the lowest at each time point, followed by group D, and that of group A was the highest; and the G2/M phase ratio increased gradualy in group B. (3) Folowing 12 and 24 hours of culture, the expression of PLK1 in group B and group D was higher than that in group A and group C (P < 0.05); in addition, the expression of PLK1 in group B was higher than that in the other three groups after 48 and 72 hours of culture (P < 0.05), and the PLK1 level in group D was higher than that in group A and group C (P < 0.05). (4) The proliferation, adhesion and invasion ability in group B were the highest at different time points, but the apoptosis rate was the lowest. Furthermore, the proliferation, adhesion and invasion abilities in group C were the lowest at different time points, and the apoptosis rate was the highest. To conclude, our experimental results show that the targeted delivery of pHSP70-shPLK1/DOX complex by magnetosomes of magnetotactic bacteria can enhance the apoptosis of osteosarcoma cells and inhibit their proliferation and invasion.

BACKGROUND:Positioning of the distal locking screws of a tibial intramedulary nail is often chalenging and time consuming. The traditional free-hand technique under fluoroscopic control involves considerable radiation exposure.OBJECTIVE: To evaluate the results of a new electromagnetic navigation system (TRIGEN-SURESHOT navigation system) for distal locking of tibial intramedullary nail in tibial diaphyseal fracture and to compare the effects with the free-hand method.METHODS: Forty-five cases of tibial diaphyseal fracture in the Second Hospital of Anhui Medical University from May 2014 to August 2015 were analyzed retrospectively, and were divided into two groups. Patients in navigation group (n=23) were treated with intramedullary nail using the TRIGEN-SURESHOT navigation system for distal locking, and the remainings in free-hand group (n=22) were given the free-hand method.RESULTS AND CONCLUSION: All cases were followed up for 17-32 months. The one-time success rate of distal locking nail operation was 100％ in the navigation group, which was significantly higher than that in the free-hand group (P < 0.05). The locking nail time in the navigation group was significantly less than that in the free-hand group (P < 0.05).No significant differences were found in the incidence of adverse events and fracture healing time between two groups (P > 0.05). To conclude, the effect of the TRIGEN-SURESHOT navigation system for distal locking of tibial intramedullary nail is satisfactory, exhibiting the advantages of short operation time, high success rate, and no radiation.

Objective To propose a concept of irreducible tibial shaft fractures and to discuss their imaging characteristics and clinical significance.Methods A retrospective study was performed in 21 patients with tibial shaft fracture who had received intraoperative intramedullary nailing after limited open reduction at Department of Orthopaedics,The Second Affiliated Hospital to Anhui Medical University from November 2013 to June 2018.They were 14 males and 7 females,aged from 21 to 66 years (average,34.9 years).There were 15 left and 6 right sides.Firstly,closed reduction was performed followed by traction,folding and rotation,but repeated attempts failed to achieve smooth reduction or insertion of guide wire.Next,local limited open reduction had to be performed for intramedullary nailing.The X-ray and CT images of the tibial fractures were collected to analyze their imaging characteristics.The imaging manifestations were characterized into 4 types:single-segment type with intact fibula,multiple-segment type,interlocking type where the distal and proximal ends interlock commonly seen in short spiral and short oblique fractures,and incarceration type where the fracture interspace is blocked by a bone fragment.The therapeutic efficacy was evaluated at the final follow-up by knee scores of The Hospital for Special Surgery (HSS) and Kofoed ankle scores.Results Of the 21 patients,2 were single-segment type,4 multiple-segment type,13 interlocking type and 2 incarceration type.They were followed up for 7 to 50 months (average,22.7 months).The fractures united after 5 to 16 months (average,7.3 months).Postoperative knee pain was observed in 3 cases and delayed fracture union in 2.Osteomyelitis,superficial wound infection,implant breakage or malunion occurred in none of the patients.The therapeutic efficacy evaluated at the final follow-up by HSS knee scores and Kofoed ankle scores revealed 15 excellent,4 good and 2 fair cases,yielding an excellent to good rate of 90.5％.Conclusion The concept of irreducible tibial shaft fractures may lead to preoperative awareness on the part of the surgeons so that ineffective repeated reductions can be spared and the damage to the blood supply to the fracture ends and the operation time can be reduced.

Objective:To explore the short-term therapeutic outcomes of femoral neck fractures fixated by Femoral Neck System (FNS).Methods:A retrospective analysis was conducted of the 16 patients with femoral neck fracture who had been admitted to the Department of Traumatology & Orthopedics, The Second Affiliated Hospital to Anhui Medical University from January to December 2019. They were 6 males and 10 females, aged from 24 to 69 years (average, 47.5 years). According to the Garden Classification, there were 3 cases of type Ⅱ, 7 cases of type Ⅲ, and 6 cases of type Ⅳ. All the 16 patients were fixated with FNS. Recorded were operation time, frequency of intraoperative fluoroscopy, intraoperative blood loss, quality of postoperative fracture reduction, hospital stay, fracture healing time, and efficacy and complications at the last follow-up.Results:The 16 patients were followed up for 5 to 16 months after operation (average, 9.3 months). According to the Garden indexes, fracture reduction was evaluated as satisfactory in all the 16 patients. The operation time in this group ranged from 25 to 115 min with an average of 41.5 min, the frequency of intraoperative fluoroscopy from 14 to 47 times with an average of 26 times, the intraoperative blood loss from 35 to 210 mL with an average of 76 mL, the hospital stay from 3 to 9 days with an average of 4.6 days, and the fracture healing time from 3 to 6 months with an average of 4.5 months. By the Harris hip scores at the last follow-up, the function of the affected hip was rated as excellent in 10 cases, good in 5 and fair in one. Follow-ups revealed no complications like infection or implant loosening.Conclusions:The FNS is a new type of simple, reliable, safe and minimally invasive internal fixation for the treatment of femoral neck fractures. The plate, bolt, anti-rotation screws and locking screws in FNS can be inserted through a single minimally invasive incision, leading to reliable fixation, limited irritation to the lateral muscular soft tissues, and fine short-term outcomes.

Objective:To compare of the efficacy of Steinman pin-assisted and manual reduction for the treatment of distal femoral fracture with anterograde intramedullary nail.Methods:From January 2014 to August 2018, data of 54 patients with distal femoral fracture were retrospectively analyzed. According to the fracture reduction methods, patients were divided into two groups: bare-handed reduction group and Steinman pin-assisted reduction group (referred to Steinman pin group). There were 16 males and 10 females in bare-handed reduction group, with age of 37.5±9.2 years (range, 21-59 years). According to AO/OTA classification, 16 cases were type 32-A, 7 type 32-B, 3 type 32-C. There were 19 males and 9 females in Steinman pin reduction group, with age of 36.4±9.8 years (range, 18-55 years). According to AO/OTA classification, 19 cases were type 32-A, 7 type 32-B, 2 type 32-C. The reduction time, fluoroscopy times, intraoperative blood loss, fracture healing time, and knee joint function score of American hospital for special surgery (HSS) were compared between the two groups.Results:The amount of blood loss during operation was 142.78±29.76 ml in the bare-handed group, and 94.81±17.71 ml in the Steinman pin group. The reduction time of fracture was 14.19±2.50 min in the bare-handed group and 5.02±1.69 min in the Steinman pin group. The times of fluoroscopy during reduction was 12.56 ±2.01 in the bare-handed group and 5.01±1.51 in the Steinman pin group. There were significant differences in the above indexes ( t=12.19, 4.02, 5.47; all P < 0.05). All 54 patients were followed up for 12-51 months, with an average of 23.4 months. All the fractures healed, and there was no delayed union or nonunion. The healing time was 7.01±1.15 months in the bare-handed group and 5.99±0.97 months in the Steinman pin group. There were no significant difference. The HSS score of knee joint function was 23.7±4.1 before operation, 61.3±4.5 at 1 month after operation, 70.2±4.2 at 2 months after operation, 78.9±5.9 at 3 months after operation, 87.9±4.6 at 6 months after operation, and 93.1±5.8 at 12 months after operation, in the bare-handed group. Meanwhile, in the Steinman pin group, 22.5±3.8 before operation, 62.2±5.1 at 1 month after operation, 69.1±4.7 at 2 months after operation, 79.2±4.3 at 3 months after operation, 88.6±5.3 at 6 months after operation, and 92.3±6.1 at 12 months after operation. There were no significant difference between the two groups ( t=1.113, 0.689, 0.908, 0.212, 0.519, 0.494, P > 0.05). There were significant differences between the two groups at each time point before and after operation ( F=716.42, 815.52, P < 0.001). There were no complications such as injection point infection, vascular and nerve injury, failure of internal fixation and so on. Conclusion:Both groups had good functional recovery after operation. However, compared with bare-handed reduction, Steinman pin groupreduction has less intraoperative blood loss, shorter reduction time and less fluoroscopy times, which is a safer reduction method.

BACKGROUND:For elderly patients with traumatic hip fractures,the related factors of prognosis are very complex,and the integrity of the lateral wall is one of the influencing factors.It is of important clinical value to understand the effect of lateral wall injury on the prognosis of femoral intertrochanteric fracture. OBJECTIVE:To evaluate the relationship between the integrity of the lateral wall and hip functional recovery and other outcomes in patients with femoral intertrochanteric fractures. METHODS:Totally 82 patients with femoral intertrochanteric fractures were screened and all patients received proximal femoral nail antirotation fixation.According to the thickness of the lateral wall,the patients were divided into the lateral wall intact group(n=31)and lateral wall risk group(n=51).The perioperative indexes,weight-bearing time,fracture healing time,hip joint function and range of motion,postoperative pain and complications were compared between the two groups. RESULTS AND CONCLUSION:(1)The time of hospitalization and the number of fluoroscopies during operation in the lateral wall intact group were significantly lower than those in the lateral wall risk group(P<0.05),but there was no significant difference in other perioperative indexes.(2)Both groups were able to get down to the ground early after surgery and finally complete weight-bearing,but in the lateral wall risk group,the time of fracture healing was longer;the time of complete weight-bearing was significantly delayed;the Harris score of the last follow-up was lower;the range of motion of hip extension and flexion and neck trunk angle on the affected side were smaller(P<0.05).(3)There was no significant difference in the incidence of postoperative complications between the two groups,but the overall incidence of complications in the lateral wall intact group was significantly lower(P<0.05).(4)In summary,after internal fixation of proximal femoral nail antirotation,patients with the intact lateral wall had a relatively better prognosis than those with risk lateral wall.

The blood-brain barrier (BBB) is a tight boundary formed between endothelial cells and astrocytes, which separates and protects brain from most pathogens as well as neural toxins in circulation. However, detailed molecular players involved in formation of BBB are not completely known. Dentin matrix protein 1 (DMP1)-proteoglycan (PG), which is known to be involved in mineralization of bones and dentin, is also expressed in soft tissues including brain with unknown functions. In the present study, we reported that DMP1-PG was expressed in brain astrocytes and enriched in BBB units. The only glycosylation site of DMP1 is serine89 (S89) in the N-terminal domain of the protein in mouse. Mutant mice with DMP1 point mutations changing S89 to glycine (S89G), which completely eradicated glycosylation of the protein, demonstrated severe BBB disruption. Another breed of DMP1 mutant mice, which lacked the C-terminal domain of DMP1, manifested normal BBB function. The polarity of S89G-DMP1 astrocytes was disrupted and cell-cell adhesion was loosened. Through a battery of analyses, we found that DMP1 glycosylation was critically required for astrocyte maturation both in vitro and in vivo. S89G-DMP1 mutant astrocytes failed to express aquaporin 4 and had reduced laminin and ZO1 expression, which resulted in disruption of BBB. Interestingly, overexpression of wild-type DMP1-PG in mouse brain driven by the nestin promoter elevated laminin and ZO1 expression beyond wild type levels and could effectively resisted intravenous mannitol-induced BBB reversible opening. Taken together, our study not only revealed a novel element, i.e., DMP1-PG, that regulated BBB formation, but also assigned a new function to DMP1-PG.
Animals ; Astrocytes ; cytology ; metabolism ; Blood-Brain Barrier ; cytology ; metabolism ; Cells, Cultured ; Extracellular Matrix Proteins ; genetics ; metabolism ; Female ; Glycosylation ; Male ; Mice ; Proteoglycans ; metabolism ; Reverse Transcriptase Polymerase Chain Reaction

Aging associated cognitive decline has been linked to dampened neural stem/progenitor cells (NSC/NPCs) activities manifested by decreased proliferation, reduced propensity to produce neurons, and increased differentiation into astrocytes. While gene transcription changes objectively reveal molecular alterations of cells undergoing various biological processes, the search for molecular mechanisms underlying aging of NSC/NPCs has been confronted by the enormous heterogeneity in cellular compositions of the brain and the complex cellular microenvironment where NSC/NPCs reside. Moreover, brain NSC/NPCs themselves are not a homogenous population, making it even more difficult to uncover NSC/NPC sub-type specific aging mechanisms. Here, using both population-based and single cell transcriptome analyses of young and aged mouse forebrain ependymal and subependymal regions and comprehensive "big-data" processing, we report that NSC/NPCs reside in a rather inflammatory environment in aged brain, which likely contributes to the differentiation bias towards astrocytes versus neurons. Moreover, single cell transcriptome analyses revealed that different aged NSC/NPC subpopulations, while all have reduced cell proliferation, use different gene transcription programs to regulate age-dependent decline in cell cycle. Interestingly, changes in cell proliferation capacity are not influenced by inflammatory cytokines, but likely result from cell intrinsic mechanisms. The Erk/Mapk pathway appears to be critically involved in regulating age-dependent changes in the capacity for NSC/NPCs to undergo clonal expansion. Together this study is the first example of using population and single cell based transcriptome analyses to unveil the molecular interplay between different NSC/NPCs and their microenvironment in the context of the aging brain.
Aging ; genetics ; Animals ; Astrocytes ; cytology ; metabolism ; Brain ; cytology ; metabolism ; Cell Differentiation ; genetics ; Cell Division ; genetics ; Cell Proliferation ; genetics ; Gene Expression Regulation ; genetics ; Mice ; Neural Stem Cells ; metabolism ; Single-Cell Analysis ; Stem Cells ; cytology ; metabolism ; Transcriptome ; genetics

In the original publication, the label of Fig. 2C should be read as "GFAP/lectin/DAPI" not "DMP1/GFAP/lectin/DAPI".

The mammalian central nervous system (CNS) is considered an immune privileged system as it is separated from the periphery by the blood brain barrier (BBB). Yet, immune functions have been postulated to heavily influence the functional state of the CNS, especially after injury or during neurodegeneration. There is controversy regarding whether adaptive immune responses are beneficial or detrimental to CNS injury repair. In this study, we utilized immunocompromised SCID mice and subjected them to spinal cord injury (SCI). We analyzed motor function, electrophysiology, histochemistry, and performed unbiased RNA-sequencing. SCID mice displayed improved CNS functional recovery compared to WT mice after SCI. Weighted gene-coexpression network analysis (WGCNA) of spinal cord transcriptomes revealed that SCID mice had reduced expression of immune function-related genes and heightened expression of neural transmission-related genes after SCI, which was confirmed by immunohistochemical analysis and was consistent with better functional recovery. Transcriptomic analyses also indicated heightened expression of neurotransmission-related genes before injury in SCID mice, suggesting that a steady state of immune-deficiency potentially led to CNS hyper-connectivity. Consequently, SCID mice without injury demonstrated worse performance in Morris water maze test. Taken together, not only reduced inflammation after injury but also dampened steady-state immune function without injury heightened the neurotransmission program, resulting in better or worse behavioral outcomes respectively. This study revealed the intricate relationship between immune and nervous systems, raising the possibility for therapeutic manipulation of neural function via immune modulation.