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.

Consumers' beef purchasing behavior across countries.

In 2022, the value of United States (US) beef and beef product exports was $11.7 billion, and the US was the world's largest beef producer and second-largest beef exporter by volume. Therefore, we conducted surveys to evaluate beef purchasing behavior among consumers in important and emerging US beef export markets, including Japan, the United Kingdom (UK), Germany, and Mexico. Results reveal differences in consumers' beef purchasing behavior across countries. Most Mexican consumers purchase beef two-to-three times a week, while consumers in other countries typically purchase it once a week. Using ordered probit models, we examined the factors associated with beef purchase frequency in each country. Japanese consumers who consider price to be an important factor when purchasing beef are less likely to purchase it frequently. German consumers, for whom brands are important when buying beef, are more likely to buy it frequently. British consumers, who consider hormone-free production to be important when purchasing beef, are less likely to buy it frequently. Mexican consumers, who consider grass-fed production to be an important factor when purchasing beef, are less likely to buy it frequently. Across all countries, individuals who purchase beef at supermarkets and from butchers are more likely to purchase it more often. Results also indicate that various consumer demographics are associated with beef purchase frequency across countries. The findings provide valuable insights for stakeholders regarding international consumer beef purchasing behavior.

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.

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.

The boom era of emerging contaminants: A review of remediating agricultural soils by biochar.

Emerging contaminants (ECs) are widely sourced persistent pollutants that pose a significant threat to the environment and human health. Their footprint spans global ecosystems, making their remediation highly challenging. In recent years, a significant amount of literature has focused on the use of biochar for remediation of heavy metals and organic pollutants in soil and water environments. However, the use of biochar for the remediation of ECs in agricultural soils has not received as much attention, and as a result, there are limited reviews available on this topic. Thus, this review aims to provide an overview of the primary types, sources, and hazards of ECs in farmland, as well as the structure, functions, and preparation types of biochar. Furthermore, this paper emphasizes the importance and prospects of three remediation strategies for ECs in cropland: (i) employing activated, modified, and composite biochar for remediation, which exhibit superior pollutant removal compared to pure biochar; (ii) exploring the potential synergistic efficiency between biochar and compost, enhancing their effectiveness in soil improvement and pollution remediation; (iii) utilizing biochar as a shelter and nutrient source for microorganisms in biochar-mediated microbial remediation, positively impacting soil properties and microbial community structure. Given the increasing global prevalence of ECs, the remediation strategies provided in this paper aim to serve as a valuable reference for future remediation of ECs-contaminated agricultural lands.

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.

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.

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.

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.

Muti-factor analysis of sport activity level after high tibial osteotomy.

BACKGROUND: Although many studies have shown that high tibial osteotomy is appropriate for active patients, there are limited multifactorial studies on patients' sport activity level after HTO in general population. METHODS: 158 patients who underwent HTO for knee osteoarthritis between January 2016 and December 2019 are included, with a 36-month follow-up. Information was collected from X-rays and questionnaire. The independent variables were age, sex, breadwinner (provide more than 50% income), sport activity level when the knee was pain-free before and after surgery, concomitant meniscal treatment history, Lysholm knee score, desire level for returning to sports. The 158 cases are divided into three groups according to their sports participation before and after operation, Chi-square tests and ANOVA analysis were adopted to identify the effect of these variables on sport activity level after HTO, and factors with statistical differences and clinical relevancies, or provided by previous research were assessed with the ordinal logistic regression analysis. RESULTS: According to sport activity level analysis, 28(17.7%) patients were categorized into the sport level-reduced group, 97(61.4%) patients into the sport level-unchanged group, and 33(20.9%) patients into the sport level-improved group. Upon ordinal logistic regression analysis, postoperative MA%, age, BMI, and preoperative Lysholm knee score were statistically significant. CONCLUSIONS: Higher postoperative MA%, younger age, lower BMI, and lower Lysholm score are associate with improvement on activity level after HTO. This finding provides valuable references in operation option and rehabilitation planning.

Adsorption properties of corn starch modified by malt amylases and crosslinking agents: A comparison between sodium trimetaphosphate and organic acids.

In order to investigate the effects of different crosslinking agents on physicochemical properties and adsorption properties of porous starch. Native corn starch was hydrolyzed by maltase and crosslinked with different crosslinking agents. Sodium trimetaphosphate crosslinked porous starch (STMP-MPS), malic acid cross-linked porous starch (MA-MPS) and citric acid cross-linked porous starch (CA-MPS) were prepared. After crosslinking, MA-MPS and CA-MPS showed a new CO stretching absorption peak at 1738 cm-1, and the crosslinking degree was much higher than that of STMP-MPS. The surface area of MA-MPS was 36 % higher than that of STMP-MPS. Compared with the average pore size of 12.43 nm of STMP-MPS, CA-MPS (14.02 nm) and MA-MPS (14.79 nm) were increased more significantly. The degradation temperature of MA-MPS and CA-MPS was increased by the introduction of ester bond, which indicates that the organic acid cross-linking strengthens the starch granules and hence more energy is required for disruption. Compared with STMP-MPS, the water absorption of MA-MPS and CA-MPS increased by 64 % and 32 %, respectively. Furthermore, the adsorption capacity of MA-MPS to essential oil was the strongest, about 4 times that of STMP-MPS. Overall, it is feasible to modify porous starch by crosslinking reaction to improve its heat resistance and adsorption properties.

Effects of polyols with different hydroxyl numbers on the structure and properties of starch straws.

To study the relationship between the number of hydroxyl groups of polyols and the plasticizing effect, the effects of different polyols including ethylene glycol, glycerol, erythritol, xylitol and sorbitol on the structure and properties of corn starch straws were analyzed and compared. The results showed that the addition of plasticizer significantly improved the performance of starch straws, which greatly improved the mechanical properties, water absorption rate (WAR) and thermal stability. However, there was no linear relationship between the plasticizing effect on starch straws and the number of hydroxyl groups in plasticizers. Fourier transform infrared (FTIR) results showed that erythritol formed the strongest intermolecular interaction with starch. Starch straws with erythritol (S-ERY) had the highest bending force (Fb = 25.78 N) and the lowest WAR. Starch straws with glycerol (S-GLY) showed the lowest relative crystallinity (RC = 12.87 %) and the highest temperature of the maximum degradation (Tdmax = 302.1 °C). In addition, after storing for 180 days, S-GLY showed higher modulus of elasticity in bending (Eb = 4.26 N/cm) and a uniform surface.

Synergistic effects on mutagenicity of tandem lesions containing 8-oxo-7,8-dihydro-2'-deoxyguanosine or Fapy•dG flanked by a 3' 5-formyl-2'-deoxyuridine in human cells.

Modified nucleotides often hinder and/or decrease the fidelity of DNA polymerases. Tandem lesions, which are comprised of DNA modifications at two contiguous nucleotide positions, can be even more detrimental to genome stability. Recently, tandem lesions containing 5-formyl-2'-deoxyuridine (5fdU) flanked at the 5'-position by 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-OxodGuo) or N-(2-deoxy-α,ß-D-erythropentofuranosyl)-N-(2,6-diamino-4-hydroxy-5-formamidopyrimidine (Fapy•dG) were discovered. We examined the replication of 5'- 8-OxodGuo-5fdU and 5'-Fapy•dG-5fdU tandem lesions in HEK 293T cells and several polymerase deficient variants by transfecting single-stranded vectors containing them. The local sequence of the tandem lesions encompasses the 273 codon of the p53 gene, a mutational hot-spot. The bypass efficiency and mutation spectra of the tandem lesions were compared to those of the isolated lesions. Replication of weakly mutagenic 5-fdU is little changed when part of the 5'- 8-OxodGuo-5fdU tandem lesion. G → T transversions attributable to 8-OxodGuo increase > 10-fold when the tandem lesion is bypassed. 5'-Fapy•dG-5fdU has a synergistic effect on the error-prone bypass of both lesions. The mutation frequency (MF) of 5'-Fapy•dG-5fdU increases 3-fold compared to isolated Fapy•dG. In addition, a 5'-adjacent Fapy•dG significantly increases the MF of 5fdU. The major mutation, G → T transversions, decrease by almost a third in hPol κ- cells, which is the opposite effect when isolated Fapy•dG in the same sequence context is replicated in HEK 293T cells in the same sequence. Steady-state kinetics indicate that hPol κ contributes to greater G → T transversions by decreasing the specificity constant for dCTP compared to an isolated Fapy•dG. The greater conformational freedom of Fapy•dG compared to 8-OxodGuo and its unusual ability to epimerize at the anomeric center is believed to be the source of the complex effects of 5'-Fapy•dG-5fdU on replication.

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.

Morphological Risk Factors for Posterior Cruciate Ligament Tear and Tibial Avulsion Injuries of the Tibial Plateau and Femoral Condyle.

BACKGROUND: Identification of morphological risk factors associated with the knee that threaten ligaments is important for understanding injury mechanisms and prevention. However, the morphological risk factors for posterior cruciate ligament (PCL) lesions are not clearly understood. PURPOSE: To investigate whether the medial tibial depth (MTD), medial and lateral posterior tibial slope, asymmetry of the medial and lateral slopes, radius of the sagittal plane medial femoral condyle, coronal tibial slope, and notch width index (NWI) were risk factors for PCL intrasubstance tearing (PCLIT) and tibial avulsion fractures (PCLAF). STUDY DESIGN: Cross-sectional study; Level of evidence, 3. METHODS: Between January 2015 and March 2022, 82 patients with isolated PCLIT, 68 patients with isolated PCLAF, and 82 controls without any ligamentous or meniscal pathologic findings as determined via physical examination and magnetic resonance imaging were included. Values were compared among the 3 groups. Logistic regression analysis was performed to confirm the risk factors. Receiver operating characteristic curves were defined for the morphological indicators and combination of risk factors. RESULTS: Logistic regression analysis revealed (1) MTD, lateral minus medial posterior tibial slope, radius of the posterior circle of the medial femoral condyle, and NWI as significant independent predictors for PCLIT and (2) MTD and NWI for PCLAF. The areas under the curve combining the 4 indicators for PCLIT and noncontact PCLIT were 0.79 (95% CI, 0.72-0.86) and 0.90 (95% CI, 0.85-0.96), respectively. The area under the curve for the combination of MTD and NWI for PCLAF was 0.78 (95% CI, 0.70-0.86). CONCLUSION: Decreased MTD and NWI were associated with an increased incidence of PCLIT and PCLAF. Increased asymmetry of the medial and lateral slopes and the radius of the posterior circle of the medial femoral condyle were associated with the presence of PCLIT. In addition, the model of a combination of risk factors showed good predictive ability for noncontact PCLIT. These findings may aid clinicians in identifying patients at risk for PCL lesions. Further studies are warranted for identifying the effect of these factors on biomechanical mechanisms.

Leucine rich repeat containing 32 accelerates tenogenic differentiation of tendon-derived stem cells and promotes Achilles tendon repair in rats.

Although many surgical or non-operative therapies have been developed to treat Achilles tendon injuries, the prognosis of which is often unsatisfactory. Recently, biologic approaches using multipotent stem cells like tendon-derived stem cells (TDSCs) pose a possible treatment option. To evaluate whether the Leucine rich repeat containing 32 (Lrrc32) affects the tenogenic differentiation of TDSCs and thus promotes Achilles tendon healing. TDSCs were infected with the recombinant Lrrc32-overexpressing lentivirus (LV-Lrrc32) and then locally injected into the injured site of rat. Four weeks after surgery, the Achilles tendon tissue (~0.5 cm) around the injured area was harvested for analysis. Pathological results showed that Lrrc32-overexpressing TDSCs significantly improved the morphological changes of the injured tendons. Specifically, the increased collagen-I expression and hydroxyproline content in extracellular matrix, and more orderly arrangement of the regenerated collagen fibers were observed in the Lrrc32 overexpression group. Moreover, 4 weeks after injection of Lrrc32-overexpressing TDSCs, the expression of tenocyte-related genes such as tenomodulin (Tnmd), scleraxis (Scx) and decorin (Dcn) were upregulated in the area of the healing tendon. These findings indicated that Lrrc32 promoted the tenogenic differentiation of TDSCs in vivo. Additionally, Lrrc32 overexpression also increased the expression of TGF-ß1 and p-SMAD2/3, suggesting that the beneficial effects of Lrrc32 on tendon repair might be associated with the expression of TGF-ß1 and p-SMAD2/3. Our findings collectively revealed that Lrrc32-overexpressed TDSCs promoted tendon healing more effectively than TDSCs alone.

Kartogenin Combined Platelet-Rich Plasma (PRP) Promoted Tendon-Bone Healing for Anterior Cruciate Ligament (ACL) Reconstruction by Suppressing Inflammatory Response Via targeting AKT/PI3K/NF-κB.

Anterior cruciate ligament (ACL) rupture is the most common sports injuries and PRP has the potential to be a kartogenin (KGN) carrier to promote collagen fibril organization and cartilage regenerative in the tendon-bone interface. This paper aimed to investigate co-injection of KGN-PRP into the bone tunnels of ACL reconstructions which could enhance tendon-bone healing graft osteointegration effectively. HPLC was used to measured release rate of KGN from KGN-PRP gel. Then, an ACL injury reconstruction model in rabbits was established and the rabbits received saline, PRP, and KGN-PRP injection onto the tendon-bone interface after reconstruction. The tissue was harvested from the tendon-bone interface at 4 weeks and 8 weeks post-surgery, and the sections were stained with Safranin O/fast green to detected tendon-bone healing. Immunochemistry staining was used to analyze VEGF, collagen I, and HIF-1α expression, and ELISA assay was used for detecting IL-6, TNF-α, and COX-2 concentrations. The expression levels of AKT/PI3K/NF-κB-related protein and mRNA were presented by Western blot and qPCR. The release rate of KGN was high within 4 h of KGN-PRP gel and followed by a slow release until 7 days. The Safranin O/fast green staining results indicated that tendon-bone interface in sham and mock group existed gap and tissue disorganization. The KGN + PRP group showed the positive color of the healing interface was more obvious and cartilage tissue began to be generated in large amounts at this interface. The maximum tensile force of KGN-PRP injection tendon-bone healing site was significantly higher than that of PRP group, and KGN-PRP effectively promoted fibro chondrogenesis and tendon-bone healing. The expression of collagen I, VEGF, and HIF-1α in regenerated tissues at the healing interface was significantly increased by KGN-PRP treatment compared with the mock and sham groups. The expressions of IL-6, TNF-α, and COX-2 after KGN-PRP treatment were significantly decreased in tendon-bone interface compared to the mock group. WB and qPCR results showed KGN-PRP treatment effectively inhibits AKT/PI3K/NF-κB activation of inflammatory pathways, thereby reducing the level of inflammation to promote wound healing. PRP is an effective carrier for KGN with the sustained release of KGN. After ACL reconstruction, injection of KGN-PRP gel significantly reduced the inflammatory response and inhibited AKT/PI3K/NF-κB activation in cartilage tissue, which promoted tendon-bone healing.

Intercondylar notch volume in patients with posterior cruciate ligament tears and tibial avulsion injuries: a study applying computed tomography.

BACKGROUND: Two relatively common forms of injury exist in the posterior cruciate ligament (PCL) after the onset of trauma: PCL tear and tibial avulsion fracture. The mechanism for the occurrence of these different forms of injury is not known. Herein, we aimed to investigate this mechanism by comparing the intercondylar notch parameters between patients with PCL tears and those with PCL avulsion fractures of the tibial insertion. METHODS: Fifty-three patients with PCL tears (37 male, 16 female: median age of 37 years: range 18-54 years) and 46 patients with avulsion fractures of tibial insertion (33 male, 13 female: median age of 33 years: range 18-55 years) were included in this study. Three-dimensional computed tomography (CT) was applied to measure the intercondylar notch width index and intercondylar notch volume. The intercondylar notch volume was simulated as the truncated-pyramid shape. Measurements of the top and bottom areas of this model were conducted on the slice containing the most proximal (S1) and most distal (S2) levels of Blumensaat's line. Femoral condyle height (h) was defined as the vertical distance between two parallel planes, and the volume was calculated as h(S1 + S2 + √(S1S2))/3. The values of S1, S2, h, notch volume, the body mass index (BMI), intercondylar notch width (NW), femoral condylar width (FW) and notch width index (NWI) were compared among the PCL tear and avulsion-fracture groups. RESULTS: The results show a significant difference in the S2 and normalized intercondylar notch volumes among patients with PCL tears and tibial avulsion injuries. Patients with PCL tears have smaller S2 and intercondylar notch volumes than those with tibial avulsion. There were no significant differences between the two groups in S1 or the 2D notch measurement parameters, such as the NW, FW and NWI. In addition, logistic regression analysis revealed notch volume and body mass index (BMI) as two significant independent predictors for PCL tears. CONCLUSION: Decreased intercondylar notch volume and increased BMI are associated with an increased incidence of PCL tears. The occurrence of PCL tears and tibial avulsion injuries is influenced by the femoral intercondylar notch volume, and the measurement of the notch volume could be useful for identifying patients at risk for PCL tears.

A low-dose therapy of fibrinogen supplement during perioperative period of total knee arthroplasty in an asymptomatic man with congenital dysfibrinogenemia: A case report.

RATIONALE: Congenital dysfibrinogenemia (CD) is a rare coagulation system disease that is often treated without unified management. Individualized treatment thereof presents clinicians with great challenges. PATIENT CONCERNS: A patient who was about to undergo total knee arthroplasty was found to have CD. DIAGNOSES: Coagulation screening revealed low fibrinogen, prolonged thrombin time, minor prolonged prothrombin time, and normal activated partial thromboplastin time were detected during admission, but no abnormal personal and family history findings were observed. Therefore, CD and hypofibrinogenemia were suspected. The gene sequencing confirmed the diagnosis of CD. INTERVENTIONS: The patient received plenty and low level of fibrinogen concentrate during 2 perioperative periods, respectively. OUTCOMES: Successful clinical outcomes were obtained using different treatment strategies. LESSONS: In contrast to prior case reports, this case illustrates the feasibility of low dosing of fibrinogen supplements within an asymptomatic patient in a selective operation. Changes in the level of fibrinogen and fibrin degradation product are of great importance for individualized treatment after supplementation.