3D printing assisted MIPO for treatment of complex middle-proximal humeral shaft fractures.

BACKGROUND: This study was designed to explore the clinical efficacy of 3-dimensional (3D) printing assisted minimally invasive percutaneous plate osteosynthesis (MIPO) technique by comparing the clinical outcomes with traditional open reduction and internal plating fixation (ORIF) for treating complex middle-proximal humerus fractures (AO 12C fracture type). MATERIALS AND METHODS: The data of 42 participants who received a complicated middle-proximal humerus fracture from the beginning of 2018 to the end of 2022 were retrospectively analyzed. All patients were assigned to two groups: MIPO with detailed preoperative planning assisted by 3D printing technique (MIPO group), and traditional ORIF (ORIF group). RESULTS: This study included 21 patients in the ORIF group and 21 patients in the MIPO group. All patients were followed-up for at least one year (mean: 16.12 ± 4.13 months), and no difference was observed in the range of shoulder joint motion (ROM), Quick Disabilities of the Arm, Shoulder and Hand (QuickDASH) scores and Constant scores between the two groups. However, the occurrence of complications (surgical incision site infection, implant loosening, bone nonunion and radial nerve palsy) in ORIF group was remarkably higher compared to the MIPO group. All the cases achieved bone union within the MIPO group. Significant differences were found in surgical time, intraoperative blood loss and fracture healing time between the two groups. CONCLUSION: Preoperative 3D printing assisted MIPO technique exhibits obvious advantages in high operational efficiency and low occurrence of complications, which is worthy of clinical application for treating complex middle-proximal humeral shaft fractures.

Three-Dimensional Printing of Polycaprolactone/Nano-Hydroxyapatite Composite Scaffolds with a Pore Size of 300/500 µm is Histocompatible and Promotes Osteogenesis Using Rabbit Cortical Bone Marrow Stem Cells.

BACKGROUND Many patients have bone defects that exceed the healing size. This study aimed to construct polycaprolactone/nano-hydroxyapatite (PCL/nHA) composite scaffolds with different pore sizes and investigate the osteogenesis and histocompatibility of cortical bone mesenchymal stem cells (BMSCs-C) seeded on it after inoculation. MATERIAL AND METHODS After mixing PCL and nHA proportionally, three-dimensional (3D) printing was used to print scaffolds. Porosity, compressive strength, and elastic modulus of PCL/nHA scaffolds were tested. The proliferation of BMSCs-C cells was examined and osteogenesis, chondrogenesis, and adipogenesis were evaluated. BMSCs-C cells were inoculated into 3D printing scaffolds, and histocompatibility between BMSCs-C cells and scaffolds was observed by the cell count kit (CCK-8) assay and LIVE/DEAD staining. After inoculating BMSCs-C cells into scaffolds, alkaline phosphatase (ALP) activity and calcium content were measured. RESULTS There was no obvious difference in characteristics between the 3 PCL/nHA composite scaffolds. The porosity, compressive strength, and elastic modulus of the 300/500-µm scaffold were between those of the 300-µm and 500-µm scaffolds. With increasing pore size, the mechanical properties of the scaffold decrease. BMSCs-C cells demonstrated faster growth and better osteogenic, adipogenic, and chondrogenic differentiation; therefore, BMSCs-C cells were selected as seed cells. PCL/nHA composite scaffolds with different pore sizes had no obvious toxicity and demonstrated good biocompatibility. All scaffolds showed higher ALP activity and calcium content. CONCLUSIONS The 300/500 µm mixed pore size scaffold took into account the mechanical properties of the 300 µm scaffold and the cell culture area of the 500 µm scaffold, therefore, 300/500 µm scaffold is a better model for the construction of tissue engineering scaffolds.

Preoperative position and protection of radial nerve by B-ultrasound combined with MIPPO for treatment of middle-inferior humerus fractures.

BACKGROUND AND PURPOSE: Open reduction and internal fixation through the posterior approach are standard methods for treating middle-inferior humerus fractures. Given the limited operative field and difficulty in locating the radial nerve, the minimally invasive percutaneous plate osteosynthesis (MIPPO) technique via the posterior approach to treat middle-inferior humerus fractures has rarely been reported. This study aims to evaluate the clinical effect of the preoperative study of the radial nerve position by B-ultrasound and its intraoperative protection combined with MIPPO in managing middle-inferior humerus fractures. METHODS: The data were studied retrospectively involving 64 participants who had surgery for middle-inferior humerus fractures from the start of 2017 to the end of 2020. Participants were divided into two groups, those treated with the MIPPO technique, including newly developed dual procedures and preoperative position and protection of radial nerve by B-ultrasound (group A), and those treated with open reduction and internal plating fixation (group B). RESULTS: All the cases were followed up for 12-34 months (an average of 25.6 ± 8.76 months), and there was no significant difference in the mean operative duration, surgical incision infection, range of motion (ROM) and MEPS (Mayo elbow performance score) for groups A and B. However, the occurrence of complications (radial nerve palsy, bone nonunion and flexible internal fixation or ruptures) in group B was significantly higher than the group A. A statistically significant difference was observed in the intraoperative blood loss, hospital stay and fracture nonunion time between the two groups. All the cases gained bone union within the MIPPO group. CONCLUSION: MIPPO via the posterior dual approach associated with preoperative position and protection of radial nerve by B-ultrasound does not increase radial nerve injury, however, it exhibits obvious advantages in the bone union, which is worthy of clinical application.

Synergistic effects of autologous platelet-rich plasma combined with an extracorporeal shock wave in treatment of long diaphysis aseptic nonunion.

INTRODUCTION: Union of long bone fractures is a complicated biological mechanism affected by numerous systemic and local variables. Disruption of any of these components may result in fracture nonunion. There are various types of clinically available treatment strategies for aseptic nonunion. Both activated platelet plasma and extracorporeal shock waves play important roles in fracture healing. This study aimed to investigate the interaction of platelet-rich plasma (PRP) and extracorporeal shock wave (ESW) in bone healing of nonunion. HYPOTHESIS: PRP and ESW have synergistic effects in treating long bone nonunion. METHODS: Between January 2016 and December 2021, a total of 60 patients with established nonunion of a long bone (18 tibias, 15 femurs, 9 humerus, 6 radii, and 12 ulnae) were included in this study, comprising 31 males and 29 females, ranging from 18 to 60 years old. Patients with bone nonunion were separated into two groups: PRP alone (Monotherapy group) and those treated with PRP combined with ESW (Combined treatment group). The two groups were compared to assess the therapeutic benefits, callus development, local problems, bone healing time, and Johner Wruhs functional classification of operated limbs. RESULTS: Fifty-five patients were followed up, 5 patients were lost to follow-up, two in the PRP group and three in the PRP+ESW group, the follow-up time varied from 6 to 18 months, with an average of 12.7±5.2 months. At 8, 12, 16, 20, and 24 weeks following intervention, the callus score in the monotherapy group was significantly lower than in the combined treatment group (p<0.05). Both groups had no swelling and infection in the soft tissue of the nonunion operation site. In the PRP+ESW group, the fracture union rate was 92.59% and the healing time was 16.3±5.2 weeks. In the PRP group, the fracture union rate was 71.43% and the healing time was 21.5±3.7 weeks. The clinical healing time of the monotherapy group was significantly longer than the combined treatment group (p<0.05). All the nonunion patients with no signs of healing were treated with revision surgery. The excellent and good rate of Johner-Wruhs functional classification of affected limbs in the monotherapy group was significantly lower than in the combined treatment group (p<0.05). CONCLUSION: PRP combined with ESW has a certain synergistic effect in treating aseptic nonunion after fracture surgery. It can significantly improve the formation of new bone, it is a minimally invasive and effective strategy to treat aseptic nonunion in a clinical setting. LEVEL OF EVIDENCE: III, retrospective, single-centre, case-control study.

Statins are associated with increased risk of squamous cell carcinoma of the skin: a whole-population study from Iceland.

Statins have been associated with an increased risk of keratinocyte carcinoma but data are limited and conflicting. Statins are hypothesized to contribute to KC through immunomodulation. A whole-population case-control study of the Icelandic population was conducted using the Icelandic Cancer Registry and Icelandic Prescription Medicine Register. These are high-quality registers which include all cancer diagnoses, as well as every prescription in the country. Cases included all first-time histologically confirmed diagnoses of (BCC), in situ squamous cell carcinoma (SCCis) and invasive SCC between 2003 and 2017. Each case was paired with 10 age- and sex-matched controls. Multivariate conditional logistic regression analysis was performed. Four thousand seven hundred patients with BCC, 1167 patients with SCCis and 1013 patients with invasive SCC were identified and paired with 47,292, 11,961 and 10,367 controls, respectively. Overall statin use was associated with an increased risk of invasive SCC and SCCis but not BCC (adjusted OR [95% CI]: 1.29 [1.11-1.50]; 1.43 [1.24-1.64]; 1.03 [0.95-1.12], respectively). Subgroup analysis demonstrated that statins were significantly associated with invasive SCC and SCCis in patients over 60, but not in those under 60. Atorvastatin was only associated with an increased risk of SCCis; whereas, simvastatin was associated with an increased risk of both invasive SCC and SCCis. This whole-population study of Iceland demonstrates that statin exposure is associated with increased risk of SCC, but not BCC, in a low UV environment. The reasons are unclear, but our results may suggest that individuals receiving atorvastatin and simvastatin have differing levels of baseline keratinocyte cancer risk or that properties of a statin other than 'statin intensity' affect association with SCC.

MRI demonstration of gadolinium deposition in bone after monthly triple-dose gadopentetate dimeglumine and correlation with frequency of hypophosphatemia.

OBJECTIVES: We retrospectively analyzed data of the BECOME trial to investigate whether serial administration of triple-dose (3-dose) gadopentetate dimeglumine would result in the development of T1 signal-to-noise (S/N) changes in the cranial diploic space and whether S/N changes correlated with on-study hypophosphatemia. METHODS: Signal intensity analysis was performed on the first year's data of the BECOME trial using 3-dose Gd (14 months, maximum number of doses, 39, mean: 36). Routine blood and urine tests were obtained each month for safety monitoring. Linear mixed regression modeling with random intercept was used to analyze monthly signal-to-noise ratio (S/N = Bone/Air) using an ROI of the diploic space created from T2W images and overlaid on T1FS (T1 fat-saturated) images. Incidence of phosphate abnormalities was analyzed using the general estimation equation; correlation of phosphate and S/N change was achieved with type 3 test of fixed effects. RESULTS: Cranial diploic space T1FS S/N increased over 14 months: S/N = 0.039 mean monthly increase (S.E. 0.008; p < 0.0001). Subjects with consistently normal phosphate levels (n = 32) experienced more of a S/N increase than patients with at least one episode of hypophosphatemia (n = 35) (0.057 vs. 0.023, respectively, p = 0.037). Those with moderate hypophosphatemia demonstrated no significant S/N increase. CONCLUSION: Monthly administration of 3-dose gadopentetate dimeglumine is associated with development of increased S/N on T1FS imaging in the cranial diploic space, suggesting Gd retention in bone. Our data suggests MRI could be used as a noninvasive method of tracking Gd retention in bone, which was more pronounced in patients with normal phosphate levels.

Association between hydrochlorothiazide and the risk of in situ and invasive squamous cell skin carcinoma and basal cell carcinoma: A population-based case-control study.

BACKGROUND: Population-based studies analyzing hydrochlorothiazide's (HCTZ's) effect on keratinocyte carcinoma, and particularly invasive squamous cell carcinoma (SCC), are lacking. OBJECTIVES: To characterize the association between HCTZ use and invasive SCC, SCC in situ (SCCis), and basal cell carcinoma (BCC). METHODS: This population-based case-control study included all 6880 patients diagnosed with first-time BCC, SCCis, and invasive SCC between 2003 and 2017 in Iceland and 69,620 population controls. Conditional logistic regression analyses were used to calculate multivariate odds ratios (ORs) for keratinocyte carcinoma associated with HCTZ use. RESULTS: A cumulative HCTZ dose above 37,500 mg was associated with increased risk of invasive SCC (OR, 1.69; 95% confidence interval [CI], 1.04-2.74). Users of HCTZ also had an increased risk of SCCis (OR, 1.24; 95% CI, 1.01-1.52) and BCC (OR, 1.14; 95% CI, 1.02-1.29). LIMITATIONS: Limitations include this study's retrospective nature with the resulting inability to adjust for ultraviolet exposure, Fitzpatrick skin type, and comorbidities. CONCLUSIONS: High cumulative exposure to HCTZ is associated with the development of keratinocyte carcinoma and, most importantly, invasive SCC. Sun protective behaviors alone may not eliminate the carcinogenic potential of HCTZ.

Gray Matter Nucleus Hyperintensity After Monthly Triple-Dose Gadopentetate Dimeglumine With Long-term Magnetic Resonance Imaging.

OBJECTIVES: Gadolinium deposition is widely believed to occur, but questions regarding accumulation pattern and permanence remain. We conducted a retrospective study of intracranial signal changes on monthly triple-dose contrast-enhanced magnetic resonance imaging (MRI) examinations from the previously published Betaseron vs. Copaxone in Multiple Sclerosis With Triple-Dose Gadolinium and 3-Tesla MRI Endpoints Trial (N = 67) to characterize the dynamics of gadolinium deposition in several deep brain nuclei and track persistence versus washout of gadolinium deposition on long-term follow-up (LTFU) examinations (N = 28) obtained approximately 10 years after enrollment in the Betaseron vs. Copaxone in Multiple Sclerosis With Triple-Dose Gadolinium and 3-Tesla MRI Endpoints Trial. MATERIALS AND METHODS: Using T2 and proton density images and using image analysis software (ITK-SNAP), manual regions of interest were created ascribing boundaries of the caudate nucleus, dentate nucleus, globus pallidus, pulvinar, putamen, white matter, and air. Intensity analysis was conducted on T1-weighted fat-saturated (fat-sat) images using the FSL package. A linear rigid-body transform was calculated from the fat-sat image at each target time point to the region of interest segmentation reference time point fat-sat image. Serial MRI signal was analyzed using linear mixed regression modeling with random intercept. Annual MRI signal changes including LTFU scans were assessed with t test. RESULTS: During monthly scanning, all gray matter structures demonstrated a significant (P < 0.0001) increase in contrast-to-noise ratio. Yearly changes in deposition showed distinctive patterns for the specific nucleus: globus pallidus showed complete retention, pulvinar showed partial washout, while dentate, caudate, and putamen returned to baseline (ie, complete washout). CONCLUSIONS: Monthly increased contrast-to-noise ratio in gray matter nuclei is consistent with gadolinium deposition over time. The study also suggests that some deep gray matter nuclei permanently retain gadolinium, whereas others demonstrate washout of soluble gadolinium.

Design and flight results of the VHF/UHF communication system of Longjiang lunar microsatellites.

As a part of China's Chang'e-4 lunar far side mission, two lunar microsatellites for low frequency radio astronomy, amateur radio and education, Longjiang-1 and Longjiang-2, were launched as secondary payloads on 20 May 2018 together with the Queqiao L2 relay satellite. On 25 May 2018, Longjiang-2 successfully inserted itself into a lunar elliptical orbit of 357 km × 13,704 km, and became the smallest spacecraft which entered lunar orbit with its own propulsion system. The satellite carried the first amateur radio communication system operating in lunar orbit, which is a VHF/UHF software defined radio (SDR) designed for operation with small ground stations. This article describes and evaluates the design of the VHF/UHF radio and the waveforms used. Flight results of the VHF/UHF radio are also presented, including operation of the radio, performance analysis of downlink signals and the first lunar orbit UHF very-long-baseline interferometry (VLBI) experiment.

A novel urinary biomarker protein panel to identify children with ureteropelvic junction obstruction - A pilot study.

INTRODUCTION AND OBJECTIVE: Reliable urinary biomarker proteins would be invaluable in identifying children with ureteropelvic junction obstruction (UPJO) as the existing biomarker proteins are inconsistent in their predictive ability. Therefore, the aim of this study was to identify consistent and reliable urinary biomarker proteins in children with UPJO. METHODS: To identify candidate biomarker proteins, total protein from age-restricted (<2 years) and sex-matched (males) control (n = 22) and UPJO (n = 21) urine samples was analyzed by mass spectrometry. Proteins that were preferentially identified in UPJO samples were selected (2-step process) and ranked according to their diagnostic odds ratio value. The top ten proteins with highest odds ratio values were selected and tested individually by ELISA. The total amount of each protein was normalized to urine creatinine and the median with interquartile ranges for control and UPJO samples was determined. Additionally, fold change (UPJO/Control) of medians of the final panel of 5 proteins was also determined. Finally, we calculated the average + 3(SD) and average + 4(SD) values of each of the 5 proteins in the control samples and used it as an arbitrary cutoff to classify individual control and UPJO samples. RESULTS: In the first step of our selection process, we identified 171 proteins in UPJO samples that were not detected in the majority of the control samples (16/22 samples, or 72.7%). Of the 171 proteins, only 50 proteins were detected in at least 11/21 (52.4%) of the UPJO samples and hence were selected in the second step. Subsequently, these 50 proteins were ranked according to the odds ratio value and the top 10 ranked proteins were validated by ELISA. Five of the 10 proteins - prostaglandin-reductase-1, ficolin-2, nicotinate-nucleotide pyrophosphorylase [carboxylating], immunoglobulin superfamily-containing leucine-rich-repeat-protein and vascular cell adhesion molecule-1 were present at higher levels in the UPJO samples (fold-change of the median protein concentrations ranging from 2.9 to 9.4) and emerged as a panel of biomarkers to identify obstructive uropathy. Finally, the order of prevalence of the 5 proteins in UPJO samples is PTGR1>FCN2>QPRT>ISLR>VCAM1. CONCLUSION: In summary, this unique screening strategy led to the identification of previously unknown biomarker proteins that when screened collectively, may reliably distinguish between obstructed vs. non-obstructed infants and may prove useful in identifying informative biomarker panels for biological samples from many diseases.

Functional interrogation of Lynch syndrome-associated MSH2 missense variants via CRISPR-Cas9 gene editing in human embryonic stem cells.

Lynch syndrome (LS) predisposes patients to cancer and is caused by germline mutations in the DNA mismatch repair (MMR) genes. Identifying the deleterious mutation, such as a frameshift or nonsense mutation, is important for confirming an LS diagnosis. However, discovery of a missense variant is often inconclusive. The effects of these variants of uncertain significance (VUS) on disease pathogenesis are unclear, though understanding their impact on protein function can help determine their significance. Laboratory functional studies performed to date have been limited by their artificial nature. We report here an in-cellulo functional assay in which we engineered site-specific MSH2 VUS using clustered regularly interspaced short palindromic repeats-Cas9 gene editing in human embryonic stem cells. This approach introduces the variant into the endogenous MSH2 loci, while simultaneously eliminating the wild-type gene. We characterized the impact of the variants on cellular MMR functions including DNA damage response signaling and the repair of DNA microsatellites. We classified the MMR functional capability of eight of 10 VUS providing valuable information for determining their likelihood of being bona fide pathogenic LS variants. This human cell-based assay system for functional testing of MMR gene VUS will facilitate the identification of high-risk LS patients.

Silver sulfadiazine nanosuspension-loaded thermosensitive hydrogel as a topical antibacterial agent.

BACKGROUND: Silver sulfadiazine (AgSD) is widely employed as an antibacterial agent for surface burn management. However, the antibacterial activity of AgSD was restrained because of the lower drug solubility and possible cytotoxicity. OBJECTIVE: This study aimed to formulate stable silver sulfadiazine/nanosuspensions (AgSD/NSs) with improved AgSD solubility and prepare a suitable carrier for AgSD/NS delivery. Nanotechnology was used to overcome the low drug dissolution rate of AgSD, while the new carrier loaded with AgSD/NS was assumed to decrease the possible cytotoxicity, enhance antibacterial activity, and promote wound healing. METHODS: AgSD/NSs were prepared by high pressure homogenization method. Poloxamer 407-based thermoresponsive hydrogels were prepared by cold method as carriers of AgSD/NS to obtain AgSD/NS-loaded thermoresponsive hydrogel. Scanning electron microscope (SEM), Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD) were used to measure the physicalchemical properties of AgSD/NSs and AgSD/NS-loaded gel. The cytotoxicity of the AgSD/NS-loaded gel was evaluated using methyl thiazolyltetrazolium assay with L929 mouse fibroblast cell lines. In vitro antibacterial activities of AgSD/NSs and AgSD/NS loaded gel were also measured. RESULTS: Stable AgSD/NSs with an average particle size of 369 nm were formulated while 1.5% P407 was selected as a stabilizer. The optimized AgSD/NS thermoresponsive hydrogel exhibited the gelation temperature of approximately 30°C. A significant improvement in solubility was observed for AgSD nanoparticles (96.7%) compared with AgSD coarse powders (12.5%). The results of FTIR and XRD revealed that the physicochemical properties of AgSD/NS were reserved after incorporating into the hydrogel. The cell viability after incubation with AgSD/NS-loaded thermoresponsive hydrogel improved from 60.7% to 90.6% compared with incubation with AgSD/NS directly. Drug release profiles from the thermoresponsive hydrogel increased compared with the commercial AgSD cream, implying less application frequency of AgSD cream clinically. In vitro antibacterial studies manifested that AgSD nanocrystallization significantly enhanced the antibacterial activity compared with the AgSD coarse powder. CONCLUSION: The combination of AgSD nanosuspensions and thermoresponsive hydrogel effectively improved the AgSD antibacterial activity and decreased the cytotoxicity. This study also suggested that a poloxamer thermoresponsive hydrogel could be used as a delivery system for other nanocrystals to decrease possible nanotoxicity.