The stereoselective pharmacokinetics of the desmethyl-phencynonate hydrochloride in beagle dogs.

The aim of this study was to investigate the chiral inversion and the stereoselective pharmacokinetic profiles of desmethyl-phencynonate hydrochloride after administration of the single isomer and its racemate to beagle dogs. A liquid chromatography with tandem mass spectrometry (LC-MS/MS) method was established for determination of the stereoisomers on chiral columns in beagle dog plasma, which met all the requirements. The chiral inversion in dogs of the desmethyl-phencynonate hydrochloride were studied after administration of the single isomer or the racemic modification. The stereoselective pharmacokinetic profiles of the desmethyl-phencynonate hydrochloride were studied by assays for simultaneous isomers after administration of the racemic modification. The results showed that the absorption of the R-configuration dosed as the single isomer was higher than it dosed as the racemic modification. The AUC(0-t), AUC(0-∞), and Cmax of the S-configuration were much higher than those of R-configuration after oral administration of the racemic desmethyl-phencynonate hydrochloride. The chiral inversion of desmethyl-phencynonate isomers could not occur in dogs after administration of the R-configuration.

Atmospheric Particle Hygroscopicity and the Influence by Oxidation State of Organic Aerosols in Urban Beijing.

A hygroscopic tandem differential mobility analyser (H-TDMA) was used to observe the size-resolved hygroscopic characteristics of submicron particles in January and April 2018 in urban Beijing. The probability distribution of the hygroscopic growth factor (HGF-PDF) in winter and spring usually showed a bimodal pattern, with more hygroscopic mode (MH) being more dominant. The seasonal variation in particle hygroscopicity was related to the origin of air mass, which received polluted southerly air masses in spring and clean northwesterly air masses in winter. Particles showed stronger hygroscopic behaviour during heavy pollution episodes (HPEs) with elevated concentrations of secondary aerosols, especially higher mass fraction of nitrate, which were indicated using the PM2.5 (particulate matter with diameter below 2.5 µm) mass concentration normalised by CO mass concentration. The hygroscopic parameter (κ) values were calculated using H-TDMA (κhtdma) and chemical composition (κchem). The closure study showed that κchem was overestimated in winter afternoon when compared with κhtdma, because the organic particle hygroscopic parameter (κorg) was overestimated in the calculations. It was influenced by the presence of a high concentration of hydrocarbon-like organic aerosol (HOA) with a weak water uptake ability. A positive relationship was observed between κorg and the ratio of oxygenated organic aerosol (OOA) and HOA, thereby indicating that the strong oxidation state enhanced the hygroscopicity of the particles. This study revealed the effect of local emission sources and secondary aerosol formation processes on particle hygroscopicity, which is of great significance for understanding the pollution formation mechanism in the North China Plain.

Nuclear receptor estrogen-related receptor gamma suppresses colorectal cancer aggressiveness by regulating Wnt/ß-catenin signaling.

Colorectal cancer (CRC) is the predominant cause of cancer-related death worldwide, because of the lack of effective therapeutic targets. Estrogen-related receptor gamma (ESRRG), which belongs to the family of nuclear receptors, functions as an important element regulating gene transcription. In our report, we identified ESRRG as a potential tumor suppressor. The decreased level of ESRRG was initially observed in CRC and was highly associated with a poor prognosis. ESRRG overexpression abrogated cell growth and metastasis in vitro and in vivo. Mechanistically, ESRRG repressed the epithelial-to-mesenchymal transition process and antagonized Wnt signaling by regulating ß-catenin degradation. In addition, significant ESRRG hypermethylation was found in CRC and inversely correlated with its expression. Consistently, the expression of ESRRG was induced after treatment with DNA demethylating agent 5-aza-2'-deoxycytidine. Taken together, these findings define a tumor-suppressive role of ESRRG in CRC, providing a potential novel therapeutic approach for this cancer.

On the fossil and non-fossil fuel sources of carbonaceous aerosol with radiocarbon and AMS-PMF methods during winter hazy days in a rural area of North China plain.

Regional transport is a key source of carbonaceous aerosol in many Chinese megacities including Beijing. The sources of carbonaceous aerosol in urban areas have been studied extensively but are poorly known in upwind rural areas. This work aims to quantify the contributions of fossil and non-fossil fuel emissions to carbonaceous aerosols at a rural site in North China Plain in winter 2016. We integrated online high resolution-time of flight-aerosol mass spectrometer (HR-TOF-AMS) observations and radiocarbon (14C) measurements of fine particles with Positive Matrix Factorization (PMF) analysis as well as Extended Gelencsér (EG) method. We found that fine particle concentration is much higher at the rural site than in Beijing during the campaign (Dec 7, 2016 to Jan 8, 2017). PMF analysis of the AMS data showed that coal-combustion related organic aerosol (CCOA + Oxidized CCOA) and more oxidized oxygenated organic aerosol (MO-OOA) contributed 48% and 30% of organic matter to non-refractory PM1 (NR-PM1) mass. About 2/3 of the OC and EC were from fossil-fuel combustion. The EG method, combining AMS-PMF and 14C data, showed that primary and secondary OC from fossil fuel contribute 35% and 22% to total carbon (TC), coal combustion emission dominates the fossil fuel sources, and biomass burning accounted for 21% of carbonaceous aerosol. In summary, our results confirm that fossil fuel combustion was the dominant source of carbonaceous aerosol during heavy pollution events in the rural areas. Significant emissions of solid fuel carbonaceous aerosols at rural areas can affect air quality in downwind cities such as Beijing and Tianjin, highlighting the benefits of energy transition from solid fuels to cleaner energy in rural areas.

Intensified wintertime secondary inorganic aerosol formation during heavy haze pollution episodes (HPEs) in Beijing, China.

Air pollution in China is complex, and the formation mechanism of chemical components in particulate matter is still unclear. This study selected three consecutive heavy haze pollution episodes (HPEs) during winter in Beijing for continuous field observation, including an episode with heavy air pollution under red alert. Clean days during the observation period were selected for comparison. The HPE characteristics of Beijing in winter were: under the influence of adverse meteorological conditions such as high relative humidity, temperature inversion and low wind speed; and strengthening of secondary transformation reactions, which further intensified the accumulation of secondary aerosols and other pollutants, promoting the explosive growth of PM2.5. PM2.5/CO values, as indicators of the contribution of secondary transformation in PM2.5, were approximately 2 times higher in the HPEs than the average PM2.5/CO during the clean period. The secondary inorganic aerosols (sulfate nitrate and ammonium salt) were significantly enhanced during the HPEs, and the conversion coefficients were remarkably improved. In addition, it is interesting to observe that the production of sulfate tended to exceed that of nitrate in the late stage of all three HPEs. The existence of aqueous phase reactions led to the explosive growth sulfur oxidation ratio (SOR) and rapid generation of sulfate under high relative humidity (RH>70%).

Application of recombinase polymerase amplification method for rapid detection of infectious laryngotracheitis virus.

Infectious laryngotracheitis is a significant respiratory disease of chickens that causes huge economic losses due to high morbidity and mortality and reduced egg production. A real-time recombinase polymerase amplification (RPA) assay was developed to accurately detect ILTV. The specific probe and primer sets were carefully designed and screened. The real-time RPA assay was carried out at 39 °C for 30 min, and results were obtained within 15 min. The results of the specificity assay showed no fluorescence signals with other avian-related viruses. The sensitivity of the assay was 1 × 102 copies/µL. The low CV value showed that the assay was reproducible. A total of 115 clinical samples were tested using the real-time RPA assay and the real-time PCR assay in parallel; the coincidence rates of the two detection methods were 100%. The results indicated that the real-time RPA assay is a specific, sensitive, rapid, and useful tool for epidemiological studies and clinical diagnosis, especially in the field and in resource-poor areas.

Significant Changes in Chemistry of Fine Particles in Wintertime Beijing from 2007 to 2017: Impact of Clean Air Actions.

The Beijing government implemented a number of clean air action plans to improve air quality in the last 10 years, which contributed to changes in the concentration of fine particles and their compositions. However, quantifying the impacts of these interventions is challenging as meteorology masks the real changes in observed concentrations. Here, we applied a machine learning technique to decouple the effect of meteorology and evaluate the changes in the chemistry of nonrefractory PM1 (particulate matter less than 1 µm) in winter 2007, 2016, and 2017 as a result of the clean air actions. The observed mass concentrations of PM1 were 74.6, 90.2, and 36.1 µg m-3 in the three winters, while the deweathered concentrations were 74.2, 78.7, and 46.3 µg m-3, respectively. The deweathered concentrations of PM1, organics, sulfate, ammonium, chloride, SO2, NO2, and CO decreased by -38, -46, -59, -24, -51, -89, -16, and -52% in 2017 in comparison to 2007. On the contrary, the deweathered concentration of nitrates increased by 4%. Our results indicate that the clean air actions implemented in 2017 were highly effective in reducing ambient concentrations of SO2, CO, and PM1 organics, sulfate, ammonium, and chloride, but the control of nitrate and PM1 organics remains a major challenge.

MicroRNA-224 suppresses osteoblast differentiation by inhibiting SMAD4.

Osteoblast differentiation was found to be regulated by a variety of cell signaling and intracellular regulatory factors. In this study, we aimed at investigating the regulatory effect of microRNA-224 on osteoblast differentiation and its molecular mechanism. Expression of miR-224 in the osteoblasts, adipose-derived mesenchymal stem cells (MSC-A), bone marrow-derived mesenchymal stem cells (MSC-B) and mbilical cord-derived mesenchymal stem cells (MSC-U) were detected using RT-PCR. Expression of miR-224 was lower in osteoblast than in the three mesenchymal stem cells and it revealed a decreasing time-dependent trend from 0 day to 28 days during osteoblast differentiation. By using alkaline phosphatase (ALP) activity assay and alizarin red S (ARS) staining, we found that the mineralization nodules decreased in miR-224-mimics group and increased in miR-224-inhibitor group. The Western blot detection of osteoblast markers, such as osteocalcin (OCN), osteopontin (OPN), bone sialoprotein (BSP), and runt related transcription factor 2 (RUNX2), also verified that overexpression of miR-224 inhibited osteoblast differentiation, while its inhibition promoted osteoblast differentiation. Luciferase reporter assay was performed in our study, which illustrated that miR-224 regulated SMAD4 directly by targeting SMAD4 3'UTR. Then after the inhibition of SMAD4, we found that lower expression of SMAD4 suppressed the osteoblast differentiation and the related signaling pathway using RT-PCR and Western blot. Our results revealed a new mechanism of osteoblast differentiation, and provided a new therapeutic agent to promote bone anabolism by targeting miR-224.

MiR-183 inhibits osteosarcoma cell growth and invasion by regulating LRP6-Wnt/ß-catenin signaling pathway.

Recent studies have demonstrated that microRNA-183 (miR-183) deregulates and plays major roles in many tumors. However, the role of miR-183 in osteosarcoma (OS) pathogenesis is still largely unknown. In this study, we first over-expressed and knocked down miR-183 in MG63 and U20S cells, respectively. Functional analyses showed that ectopic expression of miR-183 suppressed MG63 cell growth, migration, and invasion in vitro and in vivo, whereas knockdown of endogenous miR-183 in U20S cells significantly enhanced these abilities. Next, we characterized low density lipoprotein receptor-related protein 6 (LRP6) as a direct target of miR-183 that interacted with the 3'-untranslated region of LRP6. Furthermore, ectopic expression of LRP6 significantly abrogated the tumor-suppressive effect induced by miR-183. Finally, miR-183 regulated the tumor-suppressive functions in MG63 cells by suppressing the LRP6-Wnt/ß-catenin signaling pathway. Therefore, our study demonstrates that miR-183 is a tumor suppressor microRNA that plays a major role in OS.

Interleukin-1ß induces apoptosis in annulus fibrosus cells through the extracellular signal-regulated kinase pathway.

PURPOSE: The loss of intervertebral disc (IVD) cells due to excessive apoptosis induced by inflammatory cytokines is a major cause of IVD degeneration. This study aims to explore the mechanism of interleukin-1ß (IL-1ß)-induced apoptosis of annulus fibrosus cells (AFCs). It's hypothesized that IL-1ß induces apoptosis through the extracellular signal-regulated kinase (ERK) pathway in AFCs. METHODS: The mRNA and protein expression levels of apoptosis-associated genes were analyzed by quantitative real-time PCR and Western blotting. The apoptotic rate was measured by flow cytometry. Three experimental groups were established, including Control, IL-1ß, and IL-1ß+U0126 groups, respectively. RESULTS: Increase in the expression of apoptosis-associated genes including B-cell lymphoma-2 associated X (Bax), caspase-3, and caspase-9, and meanwhile, decrease in the expression of B-cell lymphoma-2 (Bcl-2) gene were found in patients with degenerative IVDs. In in vitro tests, both apoptosis and phosphorylated ERK expression in rat AFCs decreased in the IL-1ß+U0126 group compared with the IL-1ß group. The expression levels of Bax, caspase-3, and caspase-9 in AFCs decreased significantly in the IL-1ß+U0126 group compared with those in the IL-1ß group. The expression level of Bcl-2, on the other hand, significantly increased. CONCLUSIONS: Findings from this study suggest that IL-1ß induces apoptosis in AFCs through the ERK pathway, and therefore, ERK inhibition may provide certain protection against the adverse effects of IL-1ß.

A novel HRM assay for differentiating classical strains and highly pathogenic strains of type 2 porcine reproductive and respiratory syndrome virus.

Differentiation of classical strains and highly pathogenic strains of porcine reproductive and respiratory syndrome virus is crucial for effective vaccination programs and epidemiological studies. We used nested PCR and high resolution melting curve analysis with unlabeled probe to distinguish between the classical and the highly pathogenic strains of this virus. Two sets of primers and a 20 bp unlabeled probe were designed from the NSP3 gene. The unlabeled probe included two mutations specific for the classical and highly pathogenic strains of the virus. An additional primer set from the NSP2 gene of the highly pathogenic vaccine strain JXA1-R was used to detect its exclusive single nucleotide polymorphism. We tested 107 clinical samples, 21 clinical samples were positive for PRRSV (consistent with conventional PCR assay), among them four were positive for the classical strain with the remainder 17 for the highly pathogenic strain. Around 10 °C difference between probe melting temperatures showed the high discriminatory power of this method. Among highly pathogenic positive samples, three samples were determined as positive for JXA1-R vaccine-related strain with a 95% genotype confidence percentage. All these genotyping results using the high resolution melting curve assay were confirmed with DNA sequencing. This unlabeled probe method provides an alternative means to differentiate the classical strains from the highly pathogenic porcine reproductive and respiratory syndrome virus strains rapidly and accurately.

Duplex fluorescence melting curve analysis as a new tool for rapid detection and differentiation of genotype I, II and Bartha-K61 vaccine strains of pseudorabies virus.

BACKGROUND: Recently, pseudorabies (PR) outbreaks have been reported in a large number of swine herds vaccinated with the Bartha-K61 vaccine in China, the current pseudorabies virus (PRV) belonging to Genotype II is differential genetically from Bartha-K61 vaccine belonging to Genotype I. Furthermore, it has been proved that the Bartha-K61 vaccine cannot provide sufficient protection against the current PRVs in China. Therefore, the accurate and rapid identification of PRVs is essential. The objective of this study is to develop a duplex fluorescence melting curve analysis (FMCA) capable of rapid, simple, high-throughput differentiation of Chinese, European/American and Bartha-K61 vaccine strains of PRV. RESULTS: Primers 6F/6R and probes P1/P2, combined with three recombinant plasmids p-B (Bartha-K61), p-N (Genotype I), and p-H (Genotype II), were used to establish the Bicolor FMCA. FAM Tm values (probe P1) and HEX (probe P2) channels of p-B were used as reference values. Tm differences (ΔTm) between detected samples and reference plasmid p-B were calculated in each channel. Bartha-K61 vaccine samples had ΔTm values of ±1 °C in both FAM and HEX channels, Genotype I samples had ΔTm values of ±1 °C in the FAM channel and 4.38 ± 1 °C in the HEX channel, and Genotype II samples had ΔTm values of 6.52 ± 1 °C in the FAM channel and 4.38 ± 1 °C in the HEX channel. The minimum detection limit of the duplex FMCA was approximately 1 × 100 copies per reaction for p-B, p-N, and p-H. The duplex FMCA technique was used to detect and different 198 suspected clinical samples, of which 18 (9%) were positive for Genotype II strains and eight (4%) were positive for Bartha-K61 vaccine strains, and the results were compared with sequencing and phylogenetic analyses, which confirmed that the Bicolor FMCA worked correctly for all samples. CONCLUSIONS: In this study, we developed a duplex FMCA of dual-labeled, self-quenched probes that was performed for rapid detection and differentiation of Genotype I, II and Bartha-K61 vaccine strains of PRV. The duplex FMCA was rapid, simple, and high-throughput, and will likely prove useful for molecular epidemiological investigations and pathogen surveillance of PRV.

Rictor regulates the vasculogenic mimicry of melanoma via the AKT-MMP-2/9 pathway.

Vasculogenic mimicry (VM)-positive melanomas are usually associated with poor prognosis. Rictor, the key component of the rapamycin-insensitive complex of mTOR (mTORC2), is up-regulated in several cancers, especially in melanomas with poor prognosis. The aim of this study was to investigate the role of Rictor in the regulation of VM and the mechanism underlying this possible regulation. VM channels were found in 35 of 81 tested melanoma samples and high Rictor expression correlated with VM structures. Moreover, Kaplan-Meier survival curves indicated that VM structures and high Rictor expression correlated with shorter survival in patients with melanoma. In vitro, Rictor knockdown by short hairpin RNA (shRNA) significantly inhibited the ability of A375 and MUM-2B melanoma cells to form VM structures, as evidenced by most tubes remaining open. Cell cycle analysis revealed that Rictor knockdown blocked cell growth and resulted in the accumulation of cells in G2/M phase, and cell migration and invasion were greatly affected after Rictor down-regulation. Western blotting assays indicated that down-regulating Rictor significantly inhibited the phosphorylation of AKT at Ser473 and Thr308 , which subsequently inhibited the expression and activity of downstream MMP-2/9, as confirmed by real-time PCR and gelatin Zymography. MK-2206, a small-molecule inhibitor of AKT, similarly inhibited the activity of AKT and secretion of MMP-2/9, further supporting that Rictor down-regulation inhibits the phosphorylation of AKT and activity of downstream MMP-2/9 to affect VM formation. In conclusion, Rictor plays an important role in melanoma VM via the Rictor-AKT-MMP-2/9 signalling pathway.

Influence of age on results following surgery for displaced acetabular fractures in the elderly.

BACKGROUND: Elderly patients have more special medical needs when compared with young ones; thus, the results of open reduction and internal fixation (ORIF) for acetabular fractures should be stratified by age in these patients. This study seeks to determine whether the age of the patient influences the results of the ORIF for acetabular fractures. METHODS: We performed a retrospective analysis of prospectively collected data on 53 elderly patients with displaced acetabular fractures who underwent ORIF between May 2004 and May 2011. Patients were divided into two groups by age: young-old group (60-74 years) and old-old group (75-90 years). The number of patients in each group was 28 and 25. The reduction quality and clinical function was evaluated using the Matta criteria and modified Postel Merle D'Aubigne Score, respectively. Operative time, bleeding amount, and complications were recorded. RESULTS: Patients in old-old group had significantly lower anatomical reduction rate (p = 0.024), less operative time (p = 0.021), and less bleeding amount (p = 0.016) than those in the young-old group. The reduction quality in the young-old group was strongly associated with clinical function (p < 0.05). However, no difference in clinical function was detected among the different reduction qualities in the old-old group (p > 0.05). Moreover, no significant difference in clinical functions (p = 0.787) and complications (p = 0.728) was detected between the two groups. CONCLUSIONS: Old-old patients may expect comparable clinical functions and complications with young-old patients. The reduction quality in old-old patients may be not significantly associated with clinical function. Different treatment strategies may be applied for acetabular fractures with ORIF in different age groups.

Treatment of Crowe Type-IV Hip Dysplasia Using Cementless Total Hip Arthroplasty and Double Chevron Subtrochanteric Shortening Osteotomy: A 5- to 10-Year Follow-Up Study.

BACKGROUND: The purpose of this study was to evaluate the functional and radiographic results of patients with Crowe type-IV hip dysplasia treated by cementless total hip arthroplasty and double chevron subtrochanteric osteotomy. METHODS: From January 2000 to February 2006, cementless total hip arthroplasty with a double chevron subtrochanteric shortening osteotomy was performed on 18 patients (22 hips) with Crowe type-IV dysplasia. The acetabular cup was placed in the position of the anatomic hip center, and subtrochanteric femoral shortening osteotomy was performed with the use of a double chevron design. The clinical and radiographic outcomes were reviewed with a mean follow-up of 6.5 years (5-10 years). RESULTS: The mean amount of femoral subtrochanteric shortening was 38 mm (25-60 mm). All osteotomy sites were healed by 3-6 months without complications. The mean Harris Hip Score improved significantly from 47 points (35-65 points) preoperatively to 88 points (75-97 points) at the final follow-up. The Trendelenburg sign was corrected from a positive preoperative status to a negative postoperative status in 12 of 22 hips. No acetabular and femoral components have loosened or required revision during the period of follow-up. CONCLUSION: Cementless total hip arthroplasty using double chevron subtrochanteric osteotomy allowed for restoration of anatomic hip center with safely functional limb lengthening, achieved correction of preoperative limp, and good functional and radiographic outcomes for 22 Crowe type-IV dislocation hips at the time of the 5- to 10-year follow-up.

Short communication: antiviral activity of porcine IFN-λ3 against porcine epidemic diarrhea virus in vitro.

A new family of IFNs called type III IFN or IFN-λ has been described, and shown to induce antiviral activity against several viruses in the cell culture. In this study, the molecular cloning, expression, and antiporcine epidemic diarrhea virus (PEDV) activity of porcine IFN-λ3 (poIFN-λ3) were reported. The full-length poIFN-λ3 cDNA sequence encoded 196 amino acids with a 23 amino acid signal peptide. Sequence alignments showed that poIFN-λ3 had an amino acid sequence similarity to Ovis aries (78.1 %), Bos taurus (76.0 %), Tupaia belangeri (71.3 %), Equus caballus (69.9 %), and Homo sapiens (69.9 %). The phylogenetic analysis based on the genomic sequences indicated that poIFN-λ3 is located in the same branch as B. taurus and O. aries IFN-λ3. The poIFN-λ3 without a signal anchor sequence was efficiently expressed in Escherichia coli, and the purified recombinant poIFN-λ3 exhibited significant antiviral effects against PEDV in a dose- and time-dependent manner. This inhibitory effect of poIFN-λ3 on PEDV was observed under three different treatment conditions. The highest inhibition of PEDV was observed in Vero E6 cell cultures pretreated with poIFN-λ3 (prior to PEDV infection). In addition, poIFN-λ3 was able to induce the expression of IFN-stimulated genes, including ISG15, OAS1, and Mx1 in Vero E6 cells. These data demonstrate that poIFN-λ3 has antiviral activity against PEDV and may serve as a useful biotherapeutic candidate to inhibit PEDV or other viruses in swine.

Medial Protrusio Technique in Cementless Total Hip Arthroplasty for Developmental Dysplasia of the Hip: A Prospective 6- to 9-Year Follow-Up of 43 Consecutive Patients.

BACKGROUND: The medial protrusio technique may be used during total hip arthroplasty (THA) on patients with developmental dysplasia. However, studies have yet to determine whether a cementless cup can be sufficiently stable to withstand loading forces. This study aimed to assess the clinical and radiographic outcomes of this technique. Furthermore, we sought to determine the relationship between the rate of medial protrusion and the incidence of cup loosening. METHODS: Thirty-nine patients (43 hips) underwent cementless THA between April 2006 and March 2009 by using the medial protrusio technique. These patients participated in a 6- to 9-year follow-up. Their clinical and radiographic data were gathered prospectively. RESULTS: The average Harris Hip Score improved from 43.1 ± 15.4 points preoperatively to 91.9 ± 12.8 points at the final follow-up (P < .001). The mean height of hip center and the distance of hip center medialization were 2.4 ± 0.6 and 2.5 ± 0.9 cm, respectively. The rate of medial protrusion and the rate of cup coverage were 42.1 ± 12.4% and 96.8 ± 5.1%, respectively. The rate of medial protrusion ranged from 18.3% to 58.3% in 38 hips (group A) and from 61.3% to 68.9% in 5 hips (group B). None of the cups in group A loosened or failed, 2 failures occurred in group B (0% vs 40.0%; P = .011). CONCLUSIONS: Developmental dysplasia was treated through THA using the medial protrusio technique, which easily achieves a sufficient superolateral host bony coverage of the cup and promotes socket reconstruction at the true acetabulum. The rate of medial protrusion of <60% may be necessary to obtain excellent clinical and radiographic midterm results.

Silicon-Doped Titanium Dioxide Nanotubes Promoted Bone Formation on Titanium Implants.

While titanium (Ti) implants have been extensively used in orthopaedic and dental applications, the intrinsic bioinertness of untreated Ti surface usually results in insufficient osseointegration irrespective of the excellent biocompatibility and mechanical properties of it. In this study, we prepared surface modified Ti substrates in which silicon (Si) was doped into the titanium dioxide (TiO2) nanotubes on Ti surface using plasma immersion ion implantation (PIII) technology. Compared to TiO2 nanotubes and Ti alone, Si-doped TiO2 nanotubes significantly enhanced the expression of genes related to osteogenic differentiation, including Col-I, ALP, Runx2, OCN, and OPN, in mouse pre-osteoblastic MC3T3-E1 cells and deposition of mineral matrix. In vivo, the pull-out mechanical tests after two weeks of implantation in rat femur showed that Si-doped TiO2 nanotubes improved implant fixation strength by 18% and 54% compared to TiO2-NT and Ti implants, respectively. Together, findings from this study indicate that Si-doped TiO2 nanotubes promoted the osteogenic differentiation of osteoblastic cells and improved bone-Ti integration. Therefore, they may have considerable potential for the bioactive surface modification of Ti implants.

Less anterior knee pain with a routine lateral release in total knee arthroplasty without patellar resurfacing: a prospective, randomized study.

PURPOSE: Anterior knee pain is a major cause of complaint in total knee arthroplasty (TKA) without patellar resurfacing. The concept of improved patellar tracking and decreased retropatellar contact pressure for lateral retinacular release theoretically suggests that patients with lateral retinacular release in TKA would achieve a lower incidence of anterior knee pain when compared without lateral retinacular release. We sought to determine (1) whether those patients who received a routine lateral retinacular release in TKA would attain lower incidence of anterior knee pain as compared to patients who received TKA without lateral retinacular release and (2) whether lateral retinacular release would increase the lateral retinacular release-related complications. METHODS: A total of 148 patients who underwent TKA with the use of the Gemini MK II mobile bearing were randomized to receive either routine lateral retinacular release (intervention group) or not (control group). Patients were assessed by the visual analogue scale for anterior knee pain, the Knee Society clinical scoring system of knee score and function score, and patellar score for clinical function. Patients' satisfaction and lateral retinacular release-related complications were also evaluated. RESULTS: The overall incidence of anterior knee pain in the intervention group at 18 months follow-up was 5.6%, while that of the control group was 20.6% (p = 0.009). No statistical difference was detected between the two groups in terms of lateral retinacular release-related complications (n.s.), patients' satisfaction (n.s.), knee score (n.s.), function score (n.s.), and patellar score (n.s.) at 18 months follow-up. CONCLUSION: The present study suggests that routine lateral retinacular release can reduce anterior knee pain and does not increase lateral retinacular release-related complications, in TKA with the use of the Gemini MK II mobile bearing without patellar resurfacing. LEVEL OF EVIDENCE: Therapeutic, Level I.

Surgical approaches in total knee arthroplasty: a meta-analysis comparing the midvastus and subvastus to the medial peripatellar approach.

Subvastus, midvastus and medial parapatellar approaches are the most popular approaches in total knee arthroplasty (TKA). However, the superior approach in TKA still remains controversial. We therefore conducted a meta-analysis to quantitatively compare the midvastus and subvastus approaches to the medial parapatellar approach in TKA. A total of 32 randomized controlled trials (RCTs) with 2451 TKAs in 2129 patients were included in this study. The meta-analysis suggested that, when compared with the medial parapatellar approach, the midvastus approach showed better outcomes in pain and knee range of motion at postoperative 1-2weeks but also was associated with longer operative time; the subvastus approach showed better outcomes in knee range of motion at postoperative 1week, straight leg raise and lateral retinacular release.