Promoter dependent RNA polymerase II bypass of the epimerizable DNA lesion, Fapy•dG and 8-Oxo-2'-deoxyguanosine.

Formamidopyrimidine (Fapy•dG) is a major lesion arising from oxidation of dG that is produced from a common chemical precursor of 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-OxodGuo). In human cells, replication of single-stranded shuttle vectors containing Fapy•dG is more mutagenic than 8-OxodGuo. Here, we present the first data regarding promoter dependent RNA polymerase II bypass of Fapy•dG. 8-OxodGuo bypass was examined side-by-side. Experiments were carried out using double-stranded shuttle vectors in HeLa cell nuclear lysates and in HEK 293T cells. The lesions do not significantly block transcriptional bypass efficiency. Less than 2% adenosine incorporation occurred in cells when the lesions were base paired with dC. Inhibiting base excision repair in HEK 293T cells significantly increased adenosine incorporation, particularly from Fapy•dG:dC bypass which yielded ∼25% adenosine incorporation. No effect was detected upon transcriptional bypass of either lesion in nucleotide excision repair deficient cells. Transcriptional mutagenesis was significantly higher when shuttle vectors containing dA opposite one of the lesions were employed. For Fapy•dG:dA bypass, adenosine incorporation was greater than 85%; whereas 8-OxodGuo:dA yielded >20% point mutations. The combination of more frequent replication mistakes and greater error-prone Pol II bypass suggest that Fapy•dG is more mutagenic than 8-OxodGuo.

Biochemical and structural characterization of Fapy•dG replication by Human DNA polymerase ß.

N6-(2-deoxy-α,ß-d-erythro-pentofuranosyl)-2,6-diamino-4-hydroxy-5-formamido-pyrimidine (Fapy•dG) is formed from a common intermediate and in comparable amounts to the well-studied mutagenic DNA lesion 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-OxodGuo). Fapy•dG preferentially gives rise to G → T transversions and G → A transitions. However, the molecular basis by which Fapy•dG is processed by DNA polymerases during this mutagenic process remains poorly understood. To address this we investigated how DNA polymerase ß (Pol ß), a model mammalian polymerase, bypasses a templating Fapy•dG, inserts Fapy•dGTP, and extends from Fapy•dG at the primer terminus. When Fapy•dG is present in the template, Pol ß incorporates TMP less efficiently than either dCMP or dAMP. Kinetic analysis revealed that Fapy•dGTP is a poor substrate but is incorporated ∼3-times more efficiently opposite dA than dC. Extension from Fapy•dG at the 3'-terminus of a nascent primer is inefficient due to the primer terminus being poorly positioned for catalysis. Together these data indicate that mutagenic bypass of Fapy•dG is likely to be the source of the mutagenic effects of the lesion and not Fapy•dGTP. These experiments increase our understanding of the promutagenic effects of Fapy•dG.

T7 RNA Polymerase Catalyzed Transcription of the Epimerizable DNA Lesion, Fapy•dG and 8-Oxo-2'-deoxyguanosine.

Fapy•dG (N6-(2-deoxy-α,ß-D-erythro-pentofuranosyl)-2,6-diamino-4-hydroxy-5-formamidopyrimidine) and 8-OxodGuo (8-oxo-7,8-dihydro-2'-deoxyguanosine) are major products of 2'-deoxyguanosine oxidation. Fapy•dG is unusual in that it exists as a dynamic mixture of anomers. Much less is known about the effects of Fapy•dG than 8-OxodGuo on transcriptional bypass. The data presented here indicate that T7 RNA polymerase (T7 RNAP) bypass of Fapy•dG is more complex than that of 8-OxodGuo. Primer dependent transcriptional bypass of Fapy•dG by T7 RNAP is hindered compared to dG. T7 RNAP incorporates cytidine opposite Fapy•dG in a miniscaffold at least 13-fold more rapidly than A, G or U. Fitting of reaction data indicate that Fapy•dG anomers are kinetically distinguishable. Extension of a nascent transcript past Fapy•dG is weakly dependent on the nucleotide opposite the lesion. The rate constants describing extension past fast or slow reacting base pairs vary less than 2-fold as a function of the nucleotide opposite the lesion. Promoter dependent T7 RNAP bypass of Fapy•dG and 8-OxodGuo was carried out side-by-side. 8-OxodGuo bypass results in >55% A opposite it. When the shuttle vector contains a Fapy•dG:dA base pair, as high as 20% point mutations and 9% single-nucleotide deletions are produced upon Fapy•dG bypass. Error-prone bypass of a Fapy•dG:dC base pair accounts for ∼9% of the transcripts. Transcriptional bypass mutation frequencies of Fapy•dG and 8-OxodGuo measured in RNA products are comparable to or greater than replication errors, suggesting that these lesions could contribute to mutations significantly through transcription.

Molecular Mechanism of RNA Polymerase II Transcriptional Mutagenesis by the Epimerizable DNA Lesion, Fapy·dG.

Oxidative DNA lesions cause significant detrimental effects on a living species. Two major DNA lesions resulting from dG oxidation, 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-OxodGuo) and formamidopyrimidine (Fapy·dG), are produced from a common chemical intermediate. Fapy·dG is formed in comparable yields under oxygen-deficient conditions. Replicative bypass of Fapy·dG in human cells is more mutagenic than that of 8-OxodGuo. Despite the biological importance of transcriptional mutagenesis, there are no reports of the effects of Fapy·dG on RNA polymerase II (Pol II) activity. Here we perform comprehensive kinetic studies to investigate the impact of Fapy·dG on three key transcriptional fidelity checkpoint steps by Pol II: insertion, extension, and proofreading steps. The ratios of error-free versus error-prone incorporation opposite Fapy·dG are significantly reduced in comparison with undamaged dG. Similarly, Fapy·dG:A mispair is extended with comparable efficiency as that of the error-free, Fapy·dG:C base pair. The α- and ß-configurational isomers of Fapy·dG have distinct effects on Pol II insertion and extension. Pol II can preferentially cleave error-prone products by proofreading. To further understand the structural basis of transcription processing of Fapy·dG, five different structures were solved, including Fapy·dG template-loading state (apo), error-free cytidine triphosphate (CTP) binding state (prechemistry), error-prone ATP binding state (prechemistry), error-free Fapy·dG:C product state (postchemistry), and error-prone Fapy·dG:A product state (postchemistry), revealing distinctive nucleotide binding and product states. Taken together, our study provides a comprehensive mechanistic framework for better understanding how Fapy·dG lesions impact transcription and subsequent pathological consequences.

8-OxodGuo and Fapy•dG Mutagenicity in Escherichia coli Increases Significantly when They Are Part of a Tandem Lesion with 5-Formyl-2'-deoxyuridine.

Tandem lesions, which are defined by two or more contiguously damaged nucleotides, are a hallmark of ionizing radiation. Recently, tandem lesions containing 5-formyl-2'-deoxyuridine (5-fdU) flanked by a 5'-8-OxodGuo or Fapy•dG were discovered, and they are more mutagenic in human cells than the isolated lesions. In the current study, we examined replication of these tandem lesions in Escherichia coli. Bypass efficiency of both tandem lesions was reduced by 30-40% compared to the isolated lesions. Mutation frequencies (MFs) of isolated 8-OxodGuo and Fapy•dG were low, and no mutants were isolated from replication of a 5-fdU construct. The types of mutations from 8-OxodGuo were targeted G → T transversion, whereas Fapy•dG predominantly gave G → T and G deletion. 5'-8-OxodGuo-5-fdU also gave exclusively G → T mutation, which was 3-fold and 11-fold greater, without and with SOS induction, respectively, compared to that of an isolated 8-OxodGuo. In mutY/mutM cells, the MF of 8-OxodGuo and 5'-8-OxodGuo-5-fdU increased 13-fold and 7-fold, respectively. The MF of 5'-8-OxodGuo-5-fdU increased 2-fold and 3-fold in Pol II- and Pol IV-deficient cells, respectively, suggesting that these polymerases carry out largely error-free bypass. The MF of 5'- Fapy•dG-5-fdU was similar without (13 ± 1%) and with (16 ± 2%) SOS induction. Unlike the complex mutation spectrum reported earlier in human cells for 5'- Fapy•dG-5-fdU, with G → T as the major type of errors, in E. coli, the mutations were predominantly from deletion of 5-fdU. We postulate that removal of adenine-incorporated opposite 8-OxodGuo by Fpg and MutY repair proteins is partially impaired in the tandem 5'-8-OxodGuo-5-fdU, resulting in an increase in the G → T mutations, whereas a slippage mechanism may be operating in the 5'- Fapy•dG-5-fdU mutagenesis. This study showed that not only are these tandem lesions more mutagenic than the isolated lesions but they may also exhibit different types of mutations in different organisms.

A larger radius of the medial femoral posterior condyle is a risk factor for medial meniscus posterior root tears.

BACKGROUND: Studies have shown an association between medial meniscus posterior root tears (MMPRT) and morphologic characteristics of the bone. However, the association between distal femoral bone morphology and MMPRT, particularly the medial femoral posterior condyle, is poorly understood. Our study aimed to determine the association between the morphologic characteristics of the medial posterior femoral condyle and MMPRT. METHODS: A retrospective case-control study was performed from January 2021 to January 2022. After screening based on the inclusion and exclusion criteria, two matched groups were analyzed: the MMPRT group and the isolated lateral meniscus tears group. The hip-knee-ankle angle (HKA) and Kellgren-Lawrence grade (KLG) were measured on radiographs; the medial tibial slope angle (MTSA), medial tibial plateau depth (MTPD), and radius of the medial femoral posterior condyle (RMFPC) were measured on magnetic resonance imaging (MRI) in both groups. The area under the curve (AUC) and the best cutoff value for predicting MMPRT were calculated by using receiver operating characteristic (ROC) curve analysis. RESULTS: The final analysis included a total of 174 patients (87 MMPRT patients and 87 controls). Significant differences were shown in the RMFPC (17.6 ± 1.0 vs. 16.2 ± 1.0, p < 0.01) and MTSA (6.4 ± 2.0 vs. 4.0 ± 1.3, p < 0.01), which were larger than those of the control group. The MTPD (1.8 ± 0.6 vs. 2.9 ± 0.7, p < 0.01) and HKA (175.4 ± 2.2 vs. 179.0 ± 2.7, p < 0.01) of the injury group were significantly different from the control group, and both were lower than the control group. However, between the MMPRT and control groups on the KLG (2.3 ± 0.6 vs. 2.2 ± 0.6, p = 0.209), there was no statistically significant difference. Among them, the RMFPC cutoff value was calculated to be 16.8 mm by ROC curve analysis, and the sensitivity and specificity were both 81.61%. CONCLUSIONS: This study demonstrated that larger RMFPC, MTSA, smaller MTPD, and HKA were all associated with MMPRT, and RMFPC ≥ 16.8 mm was considered as a significant risk factor for MMPRT.

Mechanism of clay mineral modified biochar simultaneously immobilizes heavy metals and reduces soil carbon emissions.

Heavy metal pollution in farmland soil has become increasingly severe, and multi-element composite pollution has brought enormous harm to human production and life. Environmental changes in cold regions (such as freeze-thaw cycles and dry-wet alternations) may increase the potential physiological toxicity of heavy metals and exacerbate pollution risks. In order to reveal the effectiveness of sepiolite modified biochar in the remediation of the soil contaminated with lead (Pb), cadmium (Cd), and chromium (Cr), the rice husk biochar pyrolyzed at 500 and 800 °C were selected for remediation treatment (denoted as BC500 and BC800). Meanwhile, different proportions of sepiolite were used for modification (biochar: sepiolite = 1: 0.5 and 1: 1), denoted as MBC500/MBC800 and HBC500/HBC800, respectively. The results showed that modified biochar with sepiolite can effectively improve the immobilization of heavy metals. Under natural conservation condition, the amount of diethylenetriaminepentaacetic acid (DTPA) extractable Pb in BC500, MBC500, and HBC500 decreased by 5.95, 12.39, and 13.55%, respectively, compared to CK. Freeze-thaw cycles and dry-wet alternations activated soil heavy metals, while modified biochar increased adsorption sites and oxygen-containing functional groups under aging conditions, inhibiting the fractions transformation of heavy metals. Furthermore, freeze-thaw cycles promoted the decomposition and mineralization of soil organic carbon (SOC), while sepiolite hindered the release of active carbon through ion exchange and adsorption complexation. Among them, and the soil dissolved organic carbon (DOC) content in HBC800 decreased by 49.39% compared to BC800. Additionally, the high-temperature pyrolyzed biochar (BC800) enhanced the porosity richness and alkalinity of material, which effectively inhibited the migration and transformation of heavy metals compared to BC500, and reduced the decomposition of soil DOC.

The Efficacy and Safety of Bionic Tiger Bone Powder for the Treatment of Knee Osteoarthritis in Early Stage: A Randomized, Double-Blind, Placebo-Controlled, Multicenter Clinical Trial.

Objective: This study evaluated the efficacy and safety of bionic tiger bone powder (Jintiange) in comparison to placebo in treating knee osteoarthritis osteoporosis. Methods: A total of 248 patients were randomly allocated to a Jintiange group or a placebo group, undergoing 48 weeks of double-blind treatment. The Lequesne index, clinical symptoms, safety index (adverse events), and Patient's Global Impression of Change score were recorded at pre-determined time intervals. All P values ≤ .05 were deemed statistically significant. Results: Both groups showed a decreasing trend in the Lequesne index, with the Jintiange group's reduction significantly larger from the 12th week (P ≤ .01). Similarly, the effective rate of Lequesne score in the Jintiange group was significantly higher (P < .001). After 48 weeks, clinical symptom score differences between the Jintiange group (2.46 ± 1.74) and the placebo group (1.51 ± 1.73) were statistically significant (P < .05), as were differences in the Patient's Global Impression of Change score (P < .05). Adverse drug reactions were minimal with no significant difference between the groups (P > .05). Conclusion: Jintiange demonstrated superior efficacy over placebo in treating knee osteoporosis, with comparable safety profiles. Findings warrant further comprehensive real-world studies.

The effects of lateral meniscus posterior root tears or repair with anterior cruciate ligament reconstruction on the pressure of the patellofemoral joint: A biomechanical evaluation.

Objective: The aim of our study was to evaluate the effect of tear and repair of the lateral meniscal posterior root (LMPR) on the patellofemoral contact pressure of the knee after anterior cruciate ligament (ACL) reconstructed. Methods: This was a descriptive study. Six fresh-frozen cadaveric knees collected by The Third Hospital of Hebei Medical University from January 2019 and January 2022 were placed on a customized testing rig. Patellofemoral contact pressures were measured at 30°, 60°, and 90° of flexion using pressure-sensitive film inserted between the patella and trochlea. The following knee states were tested: ACL reconstruction and intact lateral meniscus, ACL reconstruction, and LMPR tear, and ACL reconstruction and LMPR repair. Pressure measurements were recorded for each state. Result: In the ACL-reconstructed knee, a tear of the LMPR increased patellofemoral contact pressure at 30° of knee flexion. The repair of the posterior root by transosseous pull-out suture reduced the patellofemoral contact pressure as the status of intact lateral meniscal posterior root at 30° of knee flexion. There was no statistical difference between ACL reconstruction with the intact meniscal root and with the meniscal root tear and with the meniscal root repair at 60° and 90° of knee flexion. Conclusion: The posterior root tear and repair of the lateral meniscus could have an influence on patellofemoral contact stress of the knee after ACL reconstruction at 30° of knee flexion.

Evaluation of tibial eminence morphology using magnetic resonance imaging (MRI) in juvenile patients with complete discoid lateral meniscus.

BACKGROUND: Many studies have shown that hypoplasia of knee bone morphology is related to the morphological features of the discoid lateral meniscus (DLM). However, few studies have focused on hypoplasia of tibial eminence morphology in juvenile patients with complete DLM. The purpose of this study was to determine the relationship between tibial eminence morphology characteristics and complete DLM in juvenile patients. METHODS: The DLM group comprised 34 juvenile patients with complete DLM, and the control group comprised 34 juvenile individuals, each with a normal lateral meniscus based on magnetic resonance imaging (MRI) findings. All parameters, including tibial width (TW), tibial eminence width (TEW), the height of the lateral tibial spine (HLTS), the height of the medial tibial spine (HMTS), lateral slope angle of the lateral tibial eminence (LSALTE), lateral slope angle of the medial tibial eminence (LSAMTE), tibial eminence width ratio (TEWR), height of the lateral tibial spine ratio (HLTSR), and the height of the medial tibial spine ratio (HMTSR), were recorded using coronal MR images. Statistical analyses were used to determine the differences between the two groups and whether differences were significant. RESULTS: The TEW and TEWR were significantly greater (P < 0.05), and LSALTE and LSAMTE were significantly smaller (P < 0.05) in patients in the DLM group than in participants in the control group. Receiver operating characteristic (ROC) analysis revealed that a larger TEW, above 13.4 mm, was associated with complete DLM, with a sensitivity of 77.0% and specificity of 88.2%, and a larger TEWR, above 19.7%, was associated with complete DLM, with a sensitivity of 76.5% and specificity of 91.2%. CONCLUSIONS: MR imaging can be used to diagnose tibial eminence hypoplasia in juvenile patients with complete DLM. Additionally, TEW and TEWR could help clinicians screen for complete DLM in juvenile patients.

A simple arthroscopic technique for treatment of displaced "hinged" type of posterior cruciate ligament avulsion fractures.

BACKGROUND: The surgical technique for treatment of tibial avulsion fractures of the posterior cruciate ligament (PCL) remains challenging due to the deep-located lesion and the complexity of the anatomy. The purpose of this study was to report preliminary results of an arthroscopic technique in patients with the "hinged" type PCL tibial avulsion fractures. METHODS: Twenty-eight patients with the displaced "hinged" fractures with elevation of the posterior aspect of the bony fragment were arthroscopically treated. The bony fragment was reducted and fixed with the sutures passing through only one single tibial tunnel. The clinical outcomes were assessed by Lysholm score, Tegner activity score, and the side-to-side differences of KT-1000 measurement. The reduction and union of the fracture were assessed by radiography of the knee. RESULTS: Patients were followed up for a mean of 19 (12 to 24) months. There were no surgery-related complications, and all patients regained normal range of motion of the knees at the last follow-up. The Lysholm score significantly increased from preoperative 14.78 ± 8.23 to postoperative 96.96 ± 3.62 (P = 0.000). The Tegner score was 6.78 ± 1.35 pre-injury and 6.48 ± 1.20 at the last follow-up with no statistical difference (P = 0.688). The KT-1000 side-to-side differences significantly decreased from 8.26(SD 1.86; 6 to 12) pre-operatively to 0.91 (SD 0.85; 0 to 3) (P = 0.000). X-rays showed that satisfactory reduction and solid union was achieved in all patients. CONCLUSION: The arthroscopic suture fixation through single-tibial tunnel technique yielded good clinical and radiographic outcome for treatment of displaced "hinged" type of PCL avulsion fractures.

Increased lateral and medial femoral posterior radius ratios are risk factors for anterior cruciate ligament injury.

BACKGROUND: Many studies have shown that distal femoral sagittal morphological characteristics have a clear relationship with knee joint kinematics. The aim of this study was to determine the relationship between distal femoral sagittal morphological characteristics and noncontact anterior cruciate ligament (ACL) injury. METHODS: A retrospective case-control study of 148 patients was conducted. Two age- and sex-matched cohorts (each n = 74) were analysed: a noncontact ACL injury group and a control group. Several characteristics were compared between the two groups, including the lateral femoral posterior radius (LFPR), medial femoral posterior radius (MFPR), lateral height of the distal femur (LH), medial height of the distal femur (MH), lateral femoral anteroposterior diameter (LFAP), medial femoral anteroposterior diameter (MFAP), lateral femoral posterior radius ratio (LFPRR), and medial femoral posterior radius ratio (MFPRR). Receiver operating characteristic (ROC) analysis was used to evaluate the significance of the LFPRR and MFPRR in predicting ACL injury. RESULTS: Compared with patients in the control group, patients in the ACL injury group had an increased LFPR, MFPR, MFAP, LFPRR, and MFPRR. ROC analysis revealed that an increased LFPRR above 31.7% was associated with noncontact ACL injury, with a sensitivity of 78.4% and a specificity of 58.1%; additionally. an increased MFPRR above 33.4% was associated with noncontact ACL injury, with a sensitivity of 58.1% and a specificity of 70.3%. CONCLUSION: This study showed that increased LFPRR and increased MFPRR are risk factors for developing noncontact ACL injury. These data could thus help identify individuals susceptible to ACL injuries.

A Retrospective Study of the Risk Factors for Postoperative Foot or Ankle Pain in 90 Patients with Varus Osteoarthritis of the Knee who Underwent Total Knee Arthroplasty.

BACKGROUND The reasons for foot and ankle pain following total knee arthroplasty (TKA) for knee varus osteoarthritis are unknown. This retrospective study aimed to investigate the risk factors for postoperative foot and ankle pain in patients with varus osteoarthritis of the knee who underwent TKA. MATERIAL AND METHODS We enrolled 90 patients who underwent TKA for varus knee osteoarthritis. The visual analog scale (VAS) was used to evaluate patients' foot or ankle pain before and after surgery. The correlation between independent variables (eg, age, sex, body mass index [BMI], ankle osteoarthritis, and varus angle) and foot and ankle pain in patients with osteoarthritis of the knee was measured. Moreover, radiological changes were compared between the groups with and without worsened pain. RESULTS No significant difference in VAS was found between patients <60 and ≥60 years of age (P>0.05). Male sex and BMI <30 kg/m² were weakly correlated with preoperative foot or ankle pain. However, patients with varus of ≥6° and preexisting ankle osteoarthritis had a higher incidence of foot or ankle pain before surgery. Moreover, no significant differences in radiological changes were found between the groups with and without worsened foot or ankle pain after surgery (P>0.05). CONCLUSIONS In male patients with osteoarthritis of the knee, a BMI <30 kg/m², varus of <6°, and no preexisting ankle osteoarthritis were protective factors for foot and ankle pain. TKA corrected knee and ankle malalignment. Therefore, postoperative foot and ankle pain was not associated only with TKA surgery.

Correlation between Interleukin-17 gene polymorphism and osteoarthritis susceptibility in Han Chinese population.

BACKGROUND: Interleukin-17 (IL-17), a pleiotropic cytokine, plays a significant role in the inflammatory diseases. By a pilot study with small population, IL-17 polymorphisms (IL-17A rs2275913 and IL-17F rs763780) showed a more potential risk factor in knee osteoarthritis (OA) in our recruited subjects. In the current study, the association between IL-17A rs2275913 and IL-17F rs763780and the risk of OA in a Chinese population is studied. METHODS: The IL-17A rs2275913 and IL-17F rs763780 polymorphisms were determined in 594 knee OA cases and 576 healthy controls, using polymerase chain reaction-restriction fragment length polymorphism assay. The relationship between genotype distribution and disease risk, as well as OA severity was analyzed by Chi-square test and multivariate logistic regression. RESULTS: The experimental results indicated that the polymorphism in IL-17 gene rs2275913 site were related to knee OA risk after the adjustment of BMI, sex, age, smoking and drinking status (AA vs. GG: odds ratio (OR), 1.411; 95% confidence interval (CI), 1.021-1.950; P = 0.040; A allele vs. G allele: OR, 1.192; P = 0.037; 95% CI, 1.012-1.404;). Similarly, subjects who are bearing the rs763780 variant genotypes (TC and CC) and C allele also had a higher susceptibility to knee OA compared with those who are bearing the TT genotype (TC vs. TT, OR: 1.312; P = 0.039; 95% CI: 1.017-1.692; CC vs. TT, OR: 2.812, P = 0.006, 95% CI: 1.338-5.909; C allele Vs. T allele, OR:1.413, P = 0.002, 95% CI:1.141-1.751). In the meantime, one high-risk haplotypes, AC (OR was 7.22, P < 0.01) was found. Both two polymorphisms do not correlated with OA severity based on Kellgren-Lawrence (K&L) scales. Finally, serum IL-17 levels of knee OA patients were greatly higher than those of controls (P = 0.001). CONCLUSIONS: With the limited size sample, our study shows that IL-17 gene polymorphisms possibly related to the high-risk knee OA occurrence.

Surgical medial patellofemoral ligament reconstruction versus non-surgical treatment of acute primary patellar dislocation: a prospective controlled trial.

PURPOSE: The acute primary (first-time) lateral patellar dislocation is associated with a high rate of functional disability. There is no consensus as to the choice of surgical or non-surgical treatment for these patients. The aim of this study is to compare the clinical results between the surgical (reconstruction of the medial patellofemoral ligament [MPFL]) and non-surgical treatments for acute primary patellar dislocations. METHODS: Sixty-nine skeletally mature patients (69 knees) were included in this prospective non-randomized controlled trial. At least one predisposing factor for patellar dislocation (including patella alta, high lateral patellar tilt, trochlear dysplasia, and increased TT-TG distance) was identified in the included patients. Thirty patients were treated surgically with MPFL reconstruction, and the other 39 patients were treated non-surgically. The main outcome variable was patellar redislocation within a two year follow-up period. The Kujala questionnaire was applied for analyzing the pain and the quality of life. The additional surgeries due to patellofemoral problems were also recorded. RESULTS: Patellar redislocation occurred in eight patients in the non-surgical group, while no redislocation occurred in the surgical group (P < 0.05). Four patients in non-surgical group underwent further surgery due to patellar redislocation and poor function during the follow-up period. The Kujala score and the percentage of "good/excellent" results on the Kujala score of the surgical group were significantly better than that of the non-surgical group (P < 0.05). CONCLUSIONS: The surgical MPFL reconstruction achieved better clinical outcomes compared with non-surgical treatment for the acute primary patellar dislocation in the skeletally mature patients with the presence of abnormal patellofemoral anatomy. Surgery should be considered as the better choice for these specific patients.

Rational modification of tricarboxylic acid cycle for improving L-lysine production in Corynebacterium glutamicum.

BACKGROUND: Oxaloacetate (OAA) and L-glutamate are essential precursors for the biosynthesis of L-lysine. Reasonable control of all potentially rate-limiting steps, including the precursors supply rate, is of vital importance to maximize the efficiency of L-lysine fermentation process. RESULTS: In this paper, we have rationally engineered the tricarboxylic acid (TCA) cycle that increased the carbon yield (from 36.18 to 59.65%), final titer (from 14.47 ± 0.41 to 23.86 ± 2.16 g L-1) and productivity (from 0.30 to 0.50 g L-1 h-1) of L-lysine by Corynebacterium glutamicum in shake-flask fermentation because of improving the OAA and L-glutamate availability. To do this, the phosphoenolpyruvate-pyruvate-oxaloacetate (PEP-pyruvate-OAA) node's genes ppc and pyc were inserted in the genes pck and odx loci, the P1 promoter of the TCA cycle's gene gltA was deleted, and the nature promoter of glutamate dehydrogenase-coding gene gdh was replaced by Ptac-M promoter that resulted in the final engineered strain C. glutamicum JL-69Ptac-M gdh. Furthermore, the suitable addition of biotin accelerates the L-lysine production in strain JL-69Ptac-M gdh because it elastically adjusts the carbon flux for cell growth and precursor supply. The final strain JL-69Ptac-M gdh could produce 181.5 ± 11.74 g L-1 of L-lysine with a productivity of 3.78 g L-1 h-1 and maximal specific production rate (qLys, max.) of 0.73 ± 0.16 g g-1 h-1 in fed-batch culture during adding 2.4 mg L-1 biotin with four times. CONCLUSIONS: Our results reveal that sufficient biomass, OAA and L-glutamate are equally important in the development of L-lysine high-yielding strain, and it is the first time to verify that fed-batch biotin plays a positive role in improving L-lysine production.

Comparison of Clinical Outcomes After Anterior Cruciate Ligament Reconstruction Using a Hybrid Graft Versus a Hamstring Autograft.

PURPOSE: This study aimed to compare the clinical outcomes of patients who underwent anterior cruciate ligament (ACL) reconstruction with a hybrid graft versus an autograft after 3 years of follow-up. METHODS: Among 57 patients with an ACL injury who underwent ACL reconstruction, 28 patients received a hybrid graft (gracilis and semitendinosus tendon autograft plus a soft tissue allograft) and 29 patients received an autograft (gracilis and semitendinosus tendon autograft). The 2 groups were compared after a minimum 3-year follow-up regarding International Knee Documentation Committee (IKDC) assessment of knee function and stability, pivot-shift test, Lachman test, and KT-1000 side-to-side differences. The patient-reported Tegner activity score, Lysholm score, and subjective IKDC score were also compared. Graft failures were identified by patient-reported outcomes, physical examinations, or magnetic resonance imaging, and were confirmed on second-look arthroscopy; failure rate was compared between groups. RESULTS: At final follow-up, the 2 groups significantly differed in pivot-shift test result (P = .013) and Lachman test result (P = .027). The failure rate tended to be greater in the hybrid graft group (14.3%) than in the autograft group (3.4%) (P = .148). All 5 patients with failed graft reconstruction were revised after second-look arthroscopy. The KT-1000 side-to-side differences at final follow-up were significantly inferior in the hybrid graft group (3.5 ± 2.0) compared with the autograft group (2.5 ± 1.0, P = .024). The hybrid graft group also had a lower mean Lysholm score (P = .000) and subjective IKDC score (P = .006) than the autograft group. The mean Tegner activity score was 6.8 ± 0.8 in the hybrid graft group and 6.9 ± 0.6 in the autograft group (P = .436). CONCLUSIONS: The knee stability and patient-reported scores in the autograft-irradiated allograft hybrid graft ACL reconstruction group were significantly inferior compared with those in the autograft ACL reconstruction group. LEVEL OF EVIDENCE: Level III, retrospective comparative study.

Modular One-Step Three-Component Synthesis of Tetrahydroisoquinolines Using a Catellani Strategy.

Reported is a modular one-step three-component synthesis of tetrahydroisoquinolines using a Catellani strategy. This process exploits aziridines as the alkylating reagents, through palladium/norbornene cooperative catalysis, to enable a Catellani/Heck/aza-Michael addition cascade. This mild, chemoselective, and scalable protocol has broad substrate scope (43 examples, up to 90 % yield). The most striking feature of this protocol is the excellent regioselectivity and diastereoselectivity observed for 2-alkyl- and 2-aryl-substituted aziridines to access 1,3-cis-substituted and 1,4-cis-substituted tetrahydroisoquinolines, respectively. Moreover, this is a versatile process with high step and atom economy.

Second-Look Arthroscopic Evaluation and Clinical Outcomes of Anatomic Anterior Cruciate Ligament Reconstruction with Autograft and Hybrid Graft: A Retrospective Study.

BACKGROUND Graft choice is very controversial. This study compared the second-look evaluation and clinical outcomes of anatomic ACL-R using a thin autograft versus a thick hybrid graft. MATERIAL AND METHODS Sixty-eight patients who had received ACL-R with hamstring autograft or autograft-allograft hybrid graft accepted second-look arthroscopy were grouped (autograft: n=31, age: 32.8±8.9, Male/Female: 16/15, and hybrid graft: n=37, age: 33.9±8.4, Male/Female: 27/10). Patients were evaluated with the functional score and KT-1000 test before reconstruction. The re-examination and second-look evaluation were performed at 2-year follow-up. Results were compared and further comparisons were made for grafts size >8.5 mm. RESULTS The hybrid group showed thicker graft size and bigger graft occupancy (9.0±0.5 mm vs. 8.5±0.7 mm, P=.003; 80.1±7.0% vs. 69.9±6.9%, P8.5 mm were selected and compared (autograft, n=16; hybrid, n=29). Graft tension and Synovial coverage showed a significant difference (P=.036 and P=.029). The Lysholm, IKDC, and KT-1000 test were significantly superior for the autograft than the hybrid graft (P=.036, P=.004, and P=.003, respectively). CONCLUSIONS A pure autograft is superior to a hybrid graft with same diameter in ACL-R because the augmenting allografts may be null and void. Therefore, a homogenous graft is recommended.

Prospective Randomized Comparison of Knee Stability and Proprioception for Posterior Cruciate Ligament Reconstruction With Autograft, Hybrid Graft, and γ-Irradiated Allograft.

PURPOSE: To evaluate posterior stability and proprioception after arthroscopic posterior cruciate ligament reconstruction with autograft, hybrid graft, and γ-irradiated allograft. METHODS: This prospective, randomized controlled trial (with 5 years' follow-up) included 90 patients who underwent posterior cruciate ligament reconstruction with autograft (gracilis and semitendinosus tendons), hybrid graft (γ-irradiated tibialis anterior tendon allograft and semitendinosus tendon autograft), or γ-irradiated allograft (tibialis anterior tendons). All the γ-irradiated allografts (tibialis anterior tendons) received an irradiation dose of 2.5 Mrad before distribution. Patients in this study had undergone a preoperative magnetic resonance imaging scan and physical examination. Patients were excluded from the study if they had a concomitant injury to other knee ligaments, previous surgery on the injured knee, or articular cartilage lesions greater than Outerbridge grade II. Clinical and proprioceptive evaluation results were collected preoperatively and at 3, 6, 12, 24, 36, and 60 months after surgery. RESULTS: The autograft, allograft, and hybrid graft groups were followed up for 5.5 ± 0.2 months (range, 5 to 6 years), 5.7 ± 0.3 months (range, 5 to 6 years), and 5.6 ± 0.5 months (range, 5 to 6 years), respectively. No statistically significant differences were found among the 3 groups regarding preoperative demographic factors (P > .05). The differences in physical examination findings and subjective evaluations among the 3 groups were not significant (P > .05). However, a significant difference was detected in instrumented anteroposterior measurements, with more laxity shown in the γ-irradiated allograft group than in the other 2 groups (P = .006). CONCLUSIONS: The differences in proprioceptive and functional outcomes among the 3 groups were not significant. In contrast, a significant difference was detected in instrumented anteroposterior measurements, which showed more laxity in the γ-irradiated allograft group than in the other 2 groups. However, this may not be clinically significant. LEVEL OF EVIDENCE: Level II, prospective comparative study.