-
Metabolic model guided CRISPRi identifies a central role for phosphoglycerate mutase in persistence.MSystems Jun 2024Upon nutrient starvation, serovar L2 (CTL) shifts from its normal growth to a non-replicating form, termed persistence. It is unclear if persistence reflects an...
UNLABELLED
Upon nutrient starvation, serovar L2 (CTL) shifts from its normal growth to a non-replicating form, termed persistence. It is unclear if persistence reflects an adaptive response or a lack thereof. To understand this, transcriptomics data were collected for CTL grown under nutrient-replete and nutrient-starved conditions. Applying K-means clustering on transcriptomics data revealed a global transcriptomic rewiring of CTL under stress conditions in the absence of any canonical global stress regulator. This is consistent with previous data that suggested that CTL's stress response is due to a lack of an adaptive response mechanism. To investigate the impact of this on CTL metabolism, we reconstructed a genome-scale metabolic model of CTL (iCTL278) and contextualized it with the collected transcriptomics data. Using the metabolic bottleneck analysis on contextualized iCTL278, we observed that phosphoglycerate mutase () regulates the entry of CTL to the persistence state. Our data indicate that has the highest thermodynamics driving force and lowest enzymatic cost. Furthermore, CRISPRi-driven knockdown of in the presence or absence of tryptophan revealed the importance of this gene in modulating persistence. Hence, this work, for the first time, introduces thermodynamics and enzyme cost as tools to gain a deeper understanding on CTL persistence.
IMPORTANCE
This study uses a metabolic model to investigate factors that contribute to the persistence of serovar L2 (CTL) under tryptophan and iron starvation conditions. As CTL lacks many canonical transcriptional regulators, the model was used to assess two prevailing hypotheses on persistence-that the chlamydial response to nutrient starvation represents a passive response due to the lack of regulators or that it is an active response by the bacterium. K-means clustering of stress-induced transcriptomics data revealed striking evidence in favor of the lack of adaptive (i.e., a passive) response. To find the metabolic signature of this, metabolic modeling pin-pointed pgm as a potential regulator of persistence. Thermodynamic driving force, enzyme cost, and CRISPRi knockdown of pgm supported this finding. Overall, this work introduces thermodynamic driving force and enzyme cost as a tool to understand chlamydial persistence, demonstrating how systems biology-guided CRISPRi can unravel complex bacterial phenomena.
PubMed: 38940523
DOI: 10.1128/msystems.00717-24 -
Frontiers in Bioengineering and... 2024Conventional cephalomedullary nails (CMNs) are commonly employed for internal fixation in the treatment of reverse obliquity intertrochanteric (ROI) fractures. However,...
Comparative study of a novel proximal femoral bionic nail and three conventional cephalomedullary nails for reverse obliquity intertrochanteric fractures: a finite element analysis.
PURPOSE
Conventional cephalomedullary nails (CMNs) are commonly employed for internal fixation in the treatment of reverse obliquity intertrochanteric (ROI) fractures. However, the limited effectiveness of conventional CMNs in addressing ROI fractures results in significant implant-related complications. To address challenges associated with internal fixation, a novel Proximal Femoral Bionic Nail (PFBN) has been developed.
METHODS
In this study, a finite element model was constructed using a normal femoral specimen, and biomechanical verification was conducted using the GOM non-contact optical strain measurement system. Four intramedullary fixation approaches-PFBN, Proximal Femoral Nail Antirotation InterTan nail (ITN), and Gamma nail (Gamma nail)-were employed to address three variations of ROI fractures (AO/OTA 31-A3). The biomechanical stability of the implant models was evaluated through the calculation of the von Mises stress contact pressure and displacement.
RESULTS
Compared to conventional CMNs, the PFBN group demonstrated a 9.36%-59.32% reduction in the maximum VMS at the implant. The A3.3 ROI fracture (75% bone density) was the most unstable type of fracture. In comparison to conventional CMNs, PFBN demonstrated more stable data, including VMS values (implant: 506.33 MPa, proximal fracture fragment: 34.41 MPa), contact pressure (13.28 MPa), and displacement (17.59 mm).
CONCLUSION
Compared to the PFNA, ITN, and GN, the PFBN exhibits improvements in stress concentration, stress conduction, and overall model stability in ROI fractures. The double triangle structure aligns better with the tissue structure and biomechanical properties of the proximal femur. Consequently, the PFBN has significant potential as a new fixation strategy for the clinical treatment of ROI fractures.
PubMed: 38938983
DOI: 10.3389/fbioe.2024.1393154 -
Molecular Therapy : the Journal of the... Jun 2024Gene editing technologies hold promise for enabling the next generation of adoptive cellular therapies. Conventional gene editing platforms that rely on nuclease...
Gene editing technologies hold promise for enabling the next generation of adoptive cellular therapies. Conventional gene editing platforms that rely on nuclease activity, such as Clustered regularly interspaced short palindromic repeats-CRISPR associated protein 9 (CRISPR-Cas9), allow efficient introduction of genetic modifications; however, these modifications occur via the generation of DNA double-strand breaks (DSBs) and can lead to unwanted genomic alterations and genotoxicity. Here, we apply a novel modular RNA aptamer-mediated Pin-point™ base editing platform to simultaneously introduce multiple gene knockouts and site-specific integration of a transgene in human primary T cells. We demonstrate high editing efficiency and purity at all target sites and significantly reduced frequency of chromosomal translocations compared to the conventional CRISPR-Cas9 system. Site-specific knock-in of a chimeric antigen receptor (CAR) and multiplex gene knockout are achieved within a single intervention and without the requirement for additional sequence-targeting components. The ability to perform complex genome editing efficiently and precisely highlights the potential of the Pin-point platform for application in a range of advanced cell therapies.
PubMed: 38937969
DOI: 10.1016/j.ymthe.2024.06.033 -
The Archives of Bone and Joint Surgery 2024Neglected knee dislocations are rare and challenging orthopedic injuries. We report using a traction pin to treat a neglected knee dislocation and a concurrent...
Neglected knee dislocations are rare and challenging orthopedic injuries. We report using a traction pin to treat a neglected knee dislocation and a concurrent infection. Following the primary reduction with extensive soft-tissue release, a proximal tibial traction pin was used to obtain complete reduction via traction weight change. No ligamentous repair was done for the patient. The patient's one-year follow-up showed an acceptable radiographic reduction supported by satisfactory clinical outcomes. In conclusion, the proximal tibial traction pin could be a good alternative for treating neglected knee dislocations. It makes future knee replacements more practical, a significant concern in such patients. Meanwhile, it is much more affordable than the other available techniques.
PubMed: 38919745
DOI: 10.22038/ABJS.2023.73455.3402 -
The Iowa Orthopaedic Journal 2024This study aimed to demonstrate the feasibility of lag screw exchange for painful lateral soft tissue impingement in patients initially treated with cephalomedullary...
BACKGROUND
This study aimed to demonstrate the feasibility of lag screw exchange for painful lateral soft tissue impingement in patients initially treated with cephalomedullary nailing (CMN) for an intertrochanteric hip fracture.
METHODS
Ten patients initially treated with CMN for unstable intertrochanteric fractures presenting with persistent pain and radiographic evidence of lag screw lateral migration were treated with exchange of original screw with shorter lag screw buried in the lateral cortex to prevent impingement. Patients were evaluated for resolution of pain and achievement of pre-fracture ambulatory status at 6 months post-operatively.
RESULTS
Average age was 71.5 years (range: 62-88). Average length of follow-up was 24.9 months. All patients were female, with an average Charlson Comorbidity Index of 1.0 (0-3) and average Body Mass Index of 22.2 (16.0-31.1). Five of ten patients (50.0%) were treated with a cortisone injection in the trochanteric bursa prior to screw exchange with temporary pain relief. Five (50.0%) patients presented with limited range of hip motion. Five (50.0%) had history of prior or current bisphosphonate use. Average lag screw prominence was noted to be 12.2mm (7.9-17.6mm) on radiographic evaluation. Screw exchange was performed at an average of 18.6 months (5.4-44.9 months) following the index procedure. Average operating time of the screw exchange procedure was 45.3 minutes (34-69 minutes) and blood loss was <50mL in all cases. Replacement lag screws were an average of 16.0mm (10-25mm) shorter than the initial screw. All patients achieved complete or significant resolution of lateral thigh pain, and nine (90%) returned to pre-fracture ambulatory status by eight weeks after screw exchange. All patients remained pain free at six months after screw exchange.
CONCLUSION
Lag screw exchange is a efficacious method to address the mechanical irritation of laterally protruding lag screws following IT hip fracture, while also prophylaxing against subsequent femoral neck fractures. .
Topics: Humans; Female; Hip Fractures; Aged; Fracture Fixation, Intramedullary; Bone Screws; Aged, 80 and over; Middle Aged; Treatment Outcome; Reoperation; Bone Nails; Range of Motion, Articular
PubMed: 38919366
DOI: No ID Found -
Zhongguo Xiu Fu Chong Jian Wai Ke Za... Jun 2024To compare the effectiveness of intramedullary nailing fixation via suprapatellar approach and medial parapatellar approach in semi-extended position in the treatment of... (Comparative Study)
Comparative Study
[Comparison of effectiveness of tibial intramedullary nailing fixation via suprapatellar approach and medial parapatellar approach in treatment of multiple tibial fractures].
OBJECTIVE
To compare the effectiveness of intramedullary nailing fixation via suprapatellar approach and medial parapatellar approach in semi-extended position in the treatment of multiple tibial fractures.
METHODS
The clinical data of 43 patients with multiple tibial fractures treated with intramedullary nailing fixation between July 2018 and December 2022 were retrospectively analyzed, including 23 patients treated with suprapatellar approach in semi-extended position (group A) and 20 patients with medial parapatellar approach in semi-extended position (group B). There was no significant difference in gender, age, cause of injury, time from injury to operation, AO/Orthopaedic Trauma Association (AO/OTA) classification, preoperative visual analogue scale (VAS) score, and range of motion (ROM) of the knee joint between the two groups ( >0.05). The operation time, intraoperative blood loss, incision length, intraoperative fluoroscopy frequency, and fracture healing time were recorded and compared. The VAS score and ROM of the knee joint were analyzed at 4, 8, and 12 weeks after operation, and the incidence of postoperative complications was observed; knee function was evaluated by Lysholm score at last follow-up.
RESULTS
The operations were successfully completed in both groups, and there was no complication such as nerve and blood vessel injury during operation, and all incisions healed by first intention. There was no significant difference in operation time, intraoperative blood loss, and intraoperative fluoroscopy frequency between the two groups ( >0.05), but the incision length in group B was significantly longer than that in group A ( <0.05). Patients in both groups were followed up 12-30 months, with an average of 21.1 months. The VAS score decreased and ROM increased gradually in both groups with time after operation, showing significant differences between different time points ( <0.05). The VAS score of group B was significantly lower than that of group A at 4 and 8 weeks after operation ( <0.05); there was no significant difference in VAS score and ROM between the two groups at other time points ( >0.05). There was no significant difference in fracture healing time between the two groups ( >0.05). During the follow-up, there was no complication such as internal fixator loosening, breakage, and loss of fracture reduction. At last follow-up, the Lysholm score in group B was significantly better than that in group A ( <0.05).
CONCLUSION
Both the suprapatellar approach and the medial parapatellar approach in semi-extended position can achieve satisfactory results in the treatment of multiple tibial fractures. The medial parapatellar approach has lower symptoms of early knee pain and better long-term function.
Topics: Humans; Tibial Fractures; Fracture Fixation, Intramedullary; Range of Motion, Articular; Male; Female; Treatment Outcome; Knee Joint; Fracture Healing; Operative Time; Patella; Fractures, Multiple; Retrospective Studies; Bone Nails; Middle Aged; Adult
PubMed: 38918195
DOI: 10.7507/1002-1892.202403038 -
Zhongguo Xiu Fu Chong Jian Wai Ke Za... Jun 2024To summarize the morphological characteristics of sagittal beak-like deformity of head-neck fragment in femoral intertrochanteric fractures and to investigate the...
OBJECTIVE
To summarize the morphological characteristics of sagittal beak-like deformity of head-neck fragment in femoral intertrochanteric fractures and to investigate the technical skills in fracture reduction.
METHODS
A clinical data of 31 patients with femoral intertrochanteric fractures between May 2021 and April 2023 was retrospectively analyzed. The fractures had sagittal beak-like deformity of head-neck fragment in all patients. There were 13 males and 18 females, with an average age of 76.2 years (range, 68-83 years). The time from injury to operation was 36-76 hours (mean, 51.2 hours). Fractures were classified as type A1.2 in 10 cases, type A1.3 in 11 cases, type A2.2 in 6 cases, and type A2.3 in 4 cases according to the AO/Orthopaedic Trauma Association (AO/OTA)-2018 classification; and as type A1.3 in 10 cases, type A2.1 in 11 cases, type A2.2 in 6 cases, type A2.3 in 2 cases, and type A2.4 in 2 cases according to a novel comprehensive classification for femoral intertrochanteric fractures proposed by the "Elderly Hip Fracture" Research Group of the Reparative and Reconstructive Surgery Committee of the Chinese Rehabilitation Medical Association. Based on preoperative X-ray films, CT scan and three-dimensional reconstruction, the fractures were classified into two types: type 1 (14 cases), with uncomplicated fracture morphology, severe bone interlocking and (or) soft tissue incarceration; type 2 (17 cases), with severe fracture crushing, obvious dissociation between bone blocks, and severe soft tissue hinge destruction. After the failure of the closed reduction, all patients underwent fracture reduction assisted with instrument via anterior minimal incision and proximal femoral nail antirotation nails internal fixation. The operation time, intraoperative fluoroscopy, intraoperative visible blood loss, length of hospital stay, and incidence of complications were recorded. The fracture reduction quality and stability score were assessed at immediate after operation under fluoroscopy. The fracture healing was evaluated and healing time was recorded by X-ray films. The pain visual analogue scale (VAS) score was performed at 48 hours after operation and Parker-Palmer activity score at 3 months after operation for function evaluation.
RESULTS
The operation time was 39-58 minutes (mean, 46.3 minutes); fluoroscopy was performed 13-38 times (mean, 23.5 times) during operation; the intraoperative visible blood loss was 45-90 mL (mean, 65.3 mL). The fracture reduction quality and stability score were rated as good in 29 cases and acceptable in 2 cases. The pain VAS score was 2-6 (mean, 3.1) at 48 hours after operation. Eleven patients developed deep vein thrombosis of the lower limbs after operation. Patients were hospitalized for 6-10 days (mean, 7.3 days). All patients were followed up 5-8 months (mean, 6.5 months). All fractures healed at 3.5-8.0 months after operation (mean, 4.5 months). Parker-Palmer activity score at 3 months after operation was 9 in 28 cases and 6 in 3 cases.
CONCLUSION
The femoral intertrochanteric fracture with sagittal beak-like deformity of head-neck fragment is difficult to manually reduce. The pin combined with cannulated screw insertion to the neck cortex can hold the fragment and assist fracture reduction, which is a simple and effective technique.
Topics: Humans; Male; Female; Aged; Retrospective Studies; Aged, 80 and over; Fracture Fixation, Internal; Hip Fractures; Bone Screws; Fracture Fixation, Intramedullary
PubMed: 38918192
DOI: 10.7507/1002-1892.202402004 -
Zhongguo Xiu Fu Chong Jian Wai Ke Za... Jun 2024To compare the effectiveness of long and short proximal femoral nail anti-rotation (PFNA) in the treatment of type A2.3 intertrochanteric fracture of femur (IFF). (Comparative Study)
Comparative Study
OBJECTIVE
To compare the effectiveness of long and short proximal femoral nail anti-rotation (PFNA) in the treatment of type A2.3 intertrochanteric fracture of femur (IFF).
METHODS
The clinical data of 54 patients with type A2.3 IFF admitted between January 2020 and December 2022 were retrospectively analyzed. According to the length of PFNA nail used in the operation, they were divided into long nail group (PFNA nail length>240 mm, 24 cases) and short nail group (PFNA nail length≤240 mm, 30 cases). There was no significant difference in baseline data such as gender, age, fracture side, body mass index, and time from fracture to operation between the two groups ( >0.05). The operation time, intraoperative blood loss, intraoperative fluoroscopy frequency, intraoperative reduction quality score, fracture healing, and complications of the two groups were recorded and compared. Harris score was used to evaluate the hip function of patients at 1 year after operation. According to the relationship between the fracture line of type A2.3 IFF and the lesser trochanter, the two groups of patients were divided into type Ⅰ(the fracture line extends to the level of the lesser trochanter), type Ⅱ(the fracture line extends to less than 2 cm below the lesser trochanter), and type Ⅲ (the fracture line extends to more than 2 cm below the lesser trochanter), and the postoperative stability and internal fixator loosening of each subtype were evaluated.
RESULTS
The operation time, intraoperative blood loss, and intraoperative fluoroscopy frequency in short nail group were significantly less than those in long nail group ( <0.05). There was no significant difference in the intraoperative reduction quality score between the two groups ( >0.05). Patients in both groups were followed up 12-18 months, with an average of 13.5 months. The postoperative stability score of short nail group was significantly lower than that of long nail group ( <0.05). The Harris score in the long nail group was significantly higher than that in the short nail group at 1 year after operation ( <0.05), but there was no significant difference in Harris score grading between the two groups ( >0.05). Complications occurred in 3 cases of the long nail group (including 1 case of coxa varus caused by external nail entry point and 2 cases of loose internal fixator), and 7 cases of the short nail group (including 1 case of coxa varus caused by external nail entry point and 6 cases of loose internal fixator). Neither group had any anterior femoral arch damage, there was no significant difference in the incidence of complications between the two groups ( >0.05). The number of type Ⅲ patients was relatively small and not included in the statistics; there was no significant difference in the postoperative stability score and the incidence of internal fixator loosening between the long and short nail groups in type Ⅰ patients ( >0.05). In type Ⅱ patients, the postoperative stability score and the incidence of internal fixation loosening in the long nail group were significantly better than those in the short nail group ( <0.05).
CONCLUSION
Long PFNA fixation for type A2.3 IFF has longer operation time and more intraoperative blood loss, but the overall stability of fracture is better after operation. For type A2.3 IFF with fracture line extending to less than 2 cm below the lesser trochanter, long PFNA is used for fixation, although the surgical trauma is large, but the postoperative stability is better than that of short PFNA; for type A2.3 IFF with fracture line extending to the lesser trochanter, there is no significant difference in postoperative stability between long and short PFNAs.
Topics: Humans; Bone Nails; Hip Fractures; Treatment Outcome; Fracture Fixation, Intramedullary; Operative Time; Female; Male; Fracture Healing; Blood Loss, Surgical; Femur; Retrospective Studies; Rotation; Fracture Fixation, Internal; Postoperative Complications; Aged
PubMed: 38918191
DOI: 10.7507/1002-1892.202401114 -
Zhongguo Xiu Fu Chong Jian Wai Ke Za... Jun 2024To investigate the effectiveness of HoloSight Orthopaedic Trauma Surgery Robot-assisted infra-acetabular screw placement for treatment of acetabular fractures.
OBJECTIVE
To investigate the effectiveness of HoloSight Orthopaedic Trauma Surgery Robot-assisted infra-acetabular screw placement for treatment of acetabular fractures.
METHODS
The clinical data of 23 patients with acetabular fractures treated with open reduction and internal fixation and infra-acetabular screw placement in two medical centers between June 2022 and October 2023 were retrospectively analyzed. According to the the method of infra-acetabular screw placement, the patients were divided into navigation group (10 cases, using HoloSight Orthopaedic Trauma Surgery Robot-assisted screw placement) and freehand group (13 cases, using traditional X-ray fluoroscopy to guide screw placement). There was no significant difference in gender, age, body mass index, cause of injury, time from injury to operation, and Judet-Letournel classification between the two groups ( >0.05). The time of infra-acetabular screw placement, the fluoroscopy frequency, the guide pin adjustment times, the quality of screw placement, the quality of fracture reduction, and the function of hip joint were compared between the two groups.
RESULTS
All patients completed the operation successfully. The time of screw placement, the fluoroscopy frequency, and guide pin adjustment times in the navigation group were significantly less than those in the freehand group ( <0.05). The quality of screw placement in the navigation group was significantly better than that in the freehand group ( <0.05). Patients in both groups were followed up 6-11 months, with an average of 7.7 months. There were 9 and 9 cases in the navigation group and the freehand group who achieved excellent and good fracture reduction quality at 1 week after operation, and 12 and 12 cases with excellent and good hip joint function at last follow-up, respectively, and there was no significant difference between the two groups ( >0.05). The fractures in both groups healed well, and there was no significant difference in healing time ( >0.05). During the follow-up, there was no complication related to screw placement, such as failure of internal fixation, vascular and nerve injury, incisional hernia.
CONCLUSION
In the treatment of acetabular fractures, compared with the traditional freehand screw placement, the HoloSight Orthopaedic Trauma Surgery Robot-assisted screw placement can reduce the time of screw placement, improve the accuracy of screw placement, and reduce the amount of radiation, which is an efficient, accurate, and safe surgical method.
Topics: Humans; Acetabulum; Bone Screws; Fracture Fixation, Internal; Retrospective Studies; Fractures, Bone; Robotic Surgical Procedures; Fluoroscopy; Treatment Outcome; Surgery, Computer-Assisted; Male; Female; Adult; Acute Care Surgery
PubMed: 38918190
DOI: 10.7507/1002-1892.202404045 -
European Journal of Orthopaedic Surgery... Jun 2024Supracondylar humerus (SCH) fractures account for approximately 30% of injuries for those younger than 7 years of age (Cheng et al. in J Pediatr Orthop 19:344-350,...
PURPOSE
Supracondylar humerus (SCH) fractures account for approximately 30% of injuries for those younger than 7 years of age (Cheng et al. in J Pediatr Orthop 19:344-350, 1999). Recent studies examining the association of patient age and SCH fracture outcomes have provided conflicting findings. The purpose of this study is to investigate SCH fracture outcomes in children at different ages of skeletal development.
METHODS
Retrospective review of a Level I pediatric trauma center between 2010 and 2014 was conducted. 190 patients with SCH fractures, age < 14 years, fracture type Gartland III or IV (AO/OTA 13-M 3.1 III and IV) were included. Patients were sorted into age groups: < 2 years, 4-6 years, and > 8 years. Patients were treated with either a closed or open reduction with percutaneous fixation. Clinical outcomes including postoperative elbow range of motion, nerve palsy, compartment syndrome, infection, and cubitus varus were assessed.
RESULTS
Patients in younger age groups were more likely to obtain postoperative full elbow flexion (< 2 years = 77%; 4-6 years = 66%; > 8 years = 43%) and full elbow extension (< 2 years = 96%; 4-6 years = 88%; > 8 years = 64%). Age was a significant predictor of nerve palsy on admission, mean operative time (< 2 years = 21.8 min; 4-6 years = 43.0 min; > 8 years = 80.7 min), and mean fluoroscopy time (< 2 years = 22.9 s; 4-6 years = 59.5 s; > 8 years = 171.9 s). There were no differences in rates of open reduction, compartment syndrome, pin tract infection, cubitus varus, or reoperation among groups.
CONCLUSION
Increasing age is associated with increased elbow stiffness after percutaneous fixation of Gartland Type III and Type IV SCH fractures. Older patients with SCH fractures may benefit from formal rehabilitation.
LEVEL OF EVIDENCE
III.
PubMed: 38916802
DOI: 10.1007/s00590-024-04031-4