When can total knee arthroplasty be safely performed following prior arthroscopy?

BACKGROUND: The optimal timing to perform a total knee arthroplasty (TKA) after knee arthroscopy (KA) was controversial in the literature. We aimed to 1) explore the effect of prior KA on the subsequent TKA; 2) identify who were not suitable for TKA in patients with prior KA, and 3) determine the timing of TKA following prior KA. METHODS: We retrospectively reviewed 87 TKAs with prior KA and 174 controls using propensity score matching in our institution. The minimum follow-up was 2 years. Postoperative clinical outcomes were compared between groups. Kaplan-Meier curves were created with reoperation as an endpoint. Multivariate Cox proportional hazards regressions were performed to identify risk factors of severe complications in the KA group. The two-piecewise linear regression analysis was performed to examine the optimal timing of TKA following prior KA. RESULTS: The all-cause reoperation, revision, and complication rates of the KA group were significantly higher than those of the control group (p < 0.05). The survivorship of the KA group and control group was 92.0 and 99.4% at the 2-year follow-up (p = 0.002), respectively. Male (Hazards ratio [HR] = 3.2) and prior KA for anterior cruciate ligament (ACL) injury (HR = 4.4) were associated with postoperative complications in the KA group. There was a non-linear relationship between time from prior KA to TKA and postoperative complications with the turning point at 9.4 months. CONCLUSION: Prior KA is associated with worse outcomes following subsequent TKA, especially male patients and those with prior KA for ACL injury. There is an increased risk of postoperative complications when TKA is performed within nine months of KA. Surgeons should keep these findings in mind when treating patients who are scheduled to undergo TKA with prior KA.

Enantioselective vinylation of aldehydes with the vinyl Grignard reagent catalyzed by magnesium complex of chiral BINOLs.

Enantioselective vinylation of aldehydes via direct catalytic asymmetric Grignard reaction of aldehdyes and the vinyl Grinard reagent is a long-standing challenge. This work demonstrated that the magnesium (S)-3,3'-dimethyl BINOLate enantioselectively catalyze the direct vinylation of aldehydes with the deactivated vinylmagnesium bromide by bis(2-[N,N'-dimethylamino]ethyl) ether (BDMAEE) in the addition of n-butylmagnesium chloride. The highest ee of 63% was achieved up to date.

Architecture engineering toward highly active palladium integrated titanium dioxide yolk-double-shell nanoreactor for catalytic applications.

Rational design of the hierarchical architecture of a material with well controlled functionality is crucially important for improving its properties. In this paper, we present the general strategies for rationally designing and constructing three types of hierarchical Pd integrated TiO2 double-shell architectures, i.e. yolk-double-shell TiO2 architecture (Pd@TiO2/Pd@TiO2) with yolk-type Pd nanoparticles residing inside the central cavity of the hollow TiO2 structure; ultrafine Pd nanoparticles homogenously dispersed on both the external and internal surfaces of the inner TiO2 shell; and double-shell TiO2 architecture (@TiO2/Pd@TiO2) with Pd nanoparticles solely loaded on the external surface of the inner TiO2 shell, and double-shell TiO2 architecture (@TiO2@Pd@TiO2) with Pd nanoparticles dispersed in the interlayer space of double TiO2 shells, via newly developed Pd(2+) ion-diffusion and Pd sol impregnation methodologies. These architectures are well controlled in structure, size, morphology, and configuration with Pd nanoparticles existing in various locations. Owing to the variable synergistic effects arising from the location discrepancies of Pd nanoparticle in the architectures, they exhibit remarkable variations in catalytic activity. In particular, different from previously reported yolk-shell structures, the obtained yolk-double-shell Pd@TiO2/Pd@TiO2 architecture, which is revealed for the first time, possesses a uniform hierarchical structure, narrow size distribution, and good monodispersibility, and it creates two Pd-TiO2 interfaces on the external and internal surfaces of the inner TiO2 shell, leading to the strongest synergistic effect of Pd nanoparticles with TiO2 shell. Furthermore, the interlayer chamber between the double TiO2 shells connecting with the central cavity of the hollow TiO2 structure through the mesoporous TiO2 wall forms a nanoreactor for enriching the reactants and preventing the deletion of Pd nanoparticles during the reaction, thus greatly accelerating the reaction speed. Owing to its structural features, yolk-double-shell Pd@TiO2/Pd@TiO2 architecture exhibits extremely high catalytic performance on the Suzuki-Miyaura coupling reaction. The synthetic methodologies are robust for fabricating double-shell architectures with various configurations for applications such as in catalysis, drug delivery, and medicine release. The obtained double-shell architectures may be used as novel catalyst systems with highly efficient catalytic performance for other catalytic reactions.

Ionic liquid assisted chemical strategy to TiO2 hollow nanocube assemblies with surface-fluorination and nitridation and high energy crystal facet exposure for enhanced photocatalysis.

Realization of anionic nonmetal doping and high energy crystal facet exposure in TiO2 photocatalysts has been proven to be an effective approach for significantly improving their photocatalytic performance. A facile strategy of ionic liquid assisted etching chemistry by simply hydrothermally etching hollow TiO2 spheres composed of TiO2 nanoparticles with an ionic liquid of 1-butyl-3-methylimidazolium tetrafluoroborate without any other additives is developed to create highly active anatase TiO2 nanocubes and TiO2 nanocube assemblies. With this one-pot ionic liquid assisted etching process, the surface-fluorination and nitridation and high energy {001} crystal facets exposure can be readily realized simultaneously. Compared with the benchmark materials of P25 and TiO2 nanostructures with other hierarchical architectures of hollow spheres, flaky spheres, and spindles synthesized by hydrothermally etching hollow TiO2 spheres with nonionic liquid of NH4F, the TiO2 nanocubes and TiO2 nanocube assemblies used as efficient photocatalysts show super high photocatalytic activity for degradation of methylene blue, methyl orange, and rhodamine B, due to their surface-fluorination and nitridation and high energy crystal facet exposure. The ionic liquid assisted etching chemistry is facile and robust and may be a general strategy for synthesizing other metal oxides with high energy crystal facets and surface doping for improving photocatalytic activity.

Efficient generation of myostatin (MSTN) biallelic mutations in cattle using zinc finger nucleases.

Genetically engineered zinc-finger nucleases (ZFNs) are useful for marker-free gene targeting using a one-step approach. We used ZFNs to efficiently disrupt bovine myostatin (MSTN), which was identified previously as the gene responsible for double muscling in cattle. The mutation efficiency of bovine somatic cells was approximately 20%, and the biallelic mutation efficiency was 8.3%. To evaluate the function of the mutated MSTN locus before somatic cell nuclear transfer, MSTN mRNA and protein expression was examined in four mutant cell colonies. We generated marker-gene-free cloned cattle, in which the MSTN biallelic mutations consisted of a 6-bp deletion in one of the alleles and a 117-bp deletion and 9-bp insertion in the other allele, resulting in at least four distinct mRNA splice variants. In the MSTN mutant cattle, the total amount of MSTN protein with the C-terminal domain was reduced by approximately 50%, and hypertrophied muscle fibers of the quadriceps and the double-muscled phenotype appeared at one month of age. Our proof-of-concept study is the first to produce MSTN mutations in cattle, and may allow the development of genetically modified strains of double-muscled cattle.

Double shelled hollow nanospheres with dual noble metal nanoparticle encapsulation for enhanced catalytic application.

We report the design and realization of double shelled @CeO2/M@M/TiO2 (M = Au and/or Pd) nanospheres with dual noble metal nanoparticles encapsulated in metal oxide shells via a layer-by-layer deposition process followed by an alkali etching method. The resulting nanospheres possess uniform sizes, variable shell components and thicknesses, adjustable noble metal nanoparticles encapsulated, regulable chamber spaces between the two shells, and good structural stability, which can be used as unique microreactors with extremely high catalytic activity and stability in the Suzuki-Miyaura coupling reaction, benzyl aerobic alcohol oxidation, and 4-nitrophenol reduction reaction due to their structural features with multiple interactions and strong synergistic effects between the noble metal nanoparticles and metal oxide shells, and less depletion of catalytic active species. The designed double shelled hollow @CeO2/M@M/TiO2 nanocatalysts can be used as novel catalyst systems with highly efficient catalytic performance for various catalytic reactions depending on their shell components and noble metal nanoparticles encapsulated. The synthetic strategy provides a new methodology to design high-performance and multifunctional nanocatalysts.

A magnetic double-shell microsphere as a highly efficient reusable catalyst for catalytic applications.

A novel magnetic double-shell Fe3O4@TiO2/Au@Pd@TiO2 microsphere composed of a Fe3O4 core and double TiO2 shells with Au and Pd nanoparticles encapsulated is created. The microsphere can be used as a highly efficient reusable catalyst with superior catalytic activity and stability and magnetic separable capability in reduction of 4-nitrophenol.

Hollow mesoporous ceria nanoreactors with enhanced activity and stability for catalytic application.

Novel hollow mesoporous @M/CeO(2) (M = Au, Pd, and Au-Pd) nanospheres are created. The nanospheres can be used as effective nanoreactors with superior catalytic activity and stability for reduction of 4-nitrophenol due to their hollow mesoporous structural features.

Over-expression of RAD51 or RAD54 but not RAD51/4 enhances extra-chromosomal homologous recombination in the human sarcoma (HT-1080) cell line.

RAD51 and RAD54, members of the RAD52 epistasis group, play key roles in homologous recombination (HR). The efficiency of homologous recombination (HR) can be increased by over-expression of either of them. A vector that allows co-expression of RAD51 and RAD54 was constructed to investigate interactions between the two proteins during extra-chromosomal HR. The efficiency of extra-chromosomal HR evaluated by GFP extra-chromosomal HR was enhanced (110-245%) in different transfected Human sarcoma (HT-1080) cell colonies. We observed that RAD51 clearly promotes extra-chromosomal HR; however, the actions of RAD54 in extra-chromosomal HR were weak. Our data suggest that RAD51 may function as a universal factor during HR, whereas RAD54 mainly functions in other types of HR (gene targeting or intra-chromosomal HR), which involves interaction with chromosomal DNA.

Catalytic highly enantioselective alkylation of aldehydes with deactivated grignard reagents and synthesis of bioactive intermediate secondary arylpropanols.

Because of the high reactivity of Grignard reagents, a direct, highly enantioselective Grignard reaction with aldehydes has rarely been disclosed. In this report, Grignard reagents were introduced with bis[2-(N,N'-dimethylamino)ethyl] ether (BDMAEE) to effectively deactivate their reactivity; thus, a highly enantioselective alkylation of aldehydes with Grignard reagents resulted from catalysis by (S)-BINOL-Ti(O(i)Pr)(2). It is thought that BDMAEE chelates the in situ generated salts MgBr(2) from a Schlenk equilibrium of RMgBr and Mg(O(i)Pr)Br from transmetalation of RMgBr with Ti(O(i)Pr)(4). The Mg salts can actively promote the undesired background reaction to give the racemate. The chelation definitely inhibits the catalytic activity of the Mg salts, suppresses the unwanted background reaction, and enables the highly enantioselective addition catalyzed by (S)-BINOL-Ti(O(i)Pr)(2). Consequently, the Mg salt byproducts were not removed, less Ti(O(i)Pr)(4) than RMgBr was used, and extremely low temperature was avoided in this catalytic asymmetric reaction in comparison with the research disclosed before. Various alkyl Grignard reagents were investigated in the asymmetric addition, and (i)BuMgBr resulted in the highest enantioselectivity, >99%. Furthermore, important intermediate secondary arylpropanols for chiral drug synthesis were effectively synthesized with high enantioselectivity, up to 97%, in one step.

Highly catalytic asymmetric addition of deactivated alkyl grignard reagents to aldehydes.

Generally used and highly reactive RMgBr reagents were effectively deactivated by bis[2-(N,N-dimethylamino)ethyl] ether and then were employed in the highly enantioselective addition of Grignard reagents to aldehydes. The reaction was catalyzed by the complex of commercially available (S)-BINOL and Ti(O(i-)Pr)(4) under mild conditions. Compared with the other observed Grignard reagents, alkyl Grignard reagents showed higher enantioselectivity and they achieved >99% ee.

Maternally transmitted milk containing recombinant human catalase provides protection against oxidation for mouse offspring during lactation.

Catalase plays an important role in protecting organisms against oxidative damage caused by reactive oxygen species (ROS) by degrading surplus hydrogen peroxide. Addition of exogenous catalase can alleviate injuries caused by ROS. Thus, production of human catalase through genetic engineering will meet the increasing therapeutic demand for this enzyme. In this study, we successfully expressed the recombinant gene in mouse mammary gland, and biologically active human catalase was secreted into the milk of the transgenic mice. The peroxisomal targeting sequence (PTS) within the catalase gene had no significant negative effect on the secretion of the recombinant protein. Intake of the transgenic milk by the pups was found to decrease lipid peroxidation, increase the total superoxide dismutase (T-SOD) activity in the brain, and enhance the total antioxidative capacity (T-AOC) of brain, liver, and serum. To our knowledge, this is the first example of efficient production of biologically active human catalase in the milk of transgenic animals. Our study suggests that scaled-up production in transgenic farm animals would yield sufficient human catalase for biomedical research and clinical therapies.

Nonclassical secretion of human catalase on the surface of CHO cells is more efficient than classical secretion.

There is a great demand for improved production of therapeutic proteins using mammalian cell expression systems and transgenic animals. There have been intensive endeavors to optimize production at the transcriptional and translational levels, but comparatively little attention has been paid to the secretory level, especially to nonclassical secretion. To compare the efficiencies of classical and nonclassical secretion, we expressed GFP-tagged human catalase conjugated with a classical signal peptide and with several short peptides derived from mouse Engrailed 2 (mEN2) homeoprotein for nonclassical secretion and internalization in CHO cells. Surprisingly, the results showed that the secretory efficiency was significantly greater (up to 2.3 fold) than classical secretion when the fusion protein was driven by the secretory sequence (SS) of mEN2, and up to 1.9 fold when the classical secretion process was modified by incorporating the internalization sequence (IS) of mEN2. The effect of these short peptides on nonclassical secretion and internalization may indicate potential applications in the improved production of complex therapeutic proteins in mammalian cell expression systems and transgenic animals.