OBJECTIVES: Tiletamine, a veterinary anesthetic, has emerged as a novel psychoactive substance and has been abused in many parts of the world, causing great harm to public health. However, the sensitivity of existing detection methods cannot meet the needs of forensic practice. This study aims to establish an ultra-high-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method for the determination of tiletamine and its metabolite desethyltiletamine in human biological samples, and to verify its applicability in forensic practice. METHODS: SKF_525A was used as the internal standard. Biological samples were extracted with acetonitrile containing 1 ng/mL SKF_525A, vortexed for 10 min, ultrasonicated for 20 min, centrifuged at 10 000 r/min for 10 min, and 500 μL of the supernatant was filtered through a 0.22 μm membrane. Analyses were performed using an ACQUITY UPLC H-Class PLUS system and an XEVO TQ-S Micro triple quadrupole mass spectrometer. An ACQUITY UPLC^® BEH C18 (1.7 µm, 2.1 mm×100 mm) column at a flow rate of 0.3 mL/min was used, and four mobile phase systems were tested to optimize separation. Detection used positive electrospray ionization (ESI+) in multiple reaction monitoring (MRM) mode, with quantifier ion transitions of mass to charge 224.043→179.016 for tiletamine and mass to charge 196.08→151.06 for desethyltiletamine. Calibration curves were established over 0.1-200 ng/mL in spiked blood samples. The linear range, limit of detection (LOD), and limit of quantification (LOQ) were determined. Low (5 ng/mL), medium (20 ng/mL), and high (100 ng/mL) concentrations of tiletamine were spiked into blood, liver, and kidney to evaluate precision, accuracy, matrix effect, recovery, and stability. Finally, actual forensic case samples were tested to validate applicability. RESULTS: The established UPLC-MS/MS method achieved simultaneous detection of tiletamine and desethyltiletamine in human biological samples, with retention times of 3.42 min and 2.82 min, respectively. Using mobile phase A (20 mmol/L ammonium acetate and 0.1% formic acid in water) and mobile phase B (acetonitrile) produced the best separation. In blood, tiletamine showed good linearity from 0.1-200 ng/mL (r=0.992, R²=0.983), LOD 0.03 ng/mL, LOQ 0.1 ng/mL, recovery 92%-107%, and matrix effect 71%-99%. In liver and kidney, recoveries were 91%-98% and 93%-104%, and matrix effects were 69%-96% and 72%-100%, respectively. Intra- and inter-day precision [expressed as relative standard deviation (RSD)] and accuracy [expressed as relative error (RE)] were within 15%, and samples were stable at -20 ℃. Tiletamine was detected in actual case samples at 0.37 μg/mL (blood), 0.15 μg/g (liver), 0.11 μg/g (kidney) in case 1, and 8.75 ng/mL (blood) in case 2; desethyltiletamine was also detected in blood. CONCLUSIONS The UPLC-MS/MS method is efficient, accurate, and sensitive, and is suitable for detecting tiletamine and desethyltiletamine in human biological samples.
Tandem Mass Spectrometry/methods* ; Humans ; Chromatography, High Pressure Liquid/methods* ; Substance Abuse Detection/methods* ; Liquid Chromatography-Mass Spectrometry

This consensus will introduce the characteristics of fillers used in the surgical cavities of domestic nasal surgery patients based on relevant literature and expert opinions. It will also provide recommendations for the selection of cavity fillers for different nasal diseases, with chronic sinusitis as a representative example.
Humans ; Nasal Cavity/surgery* ; Nasal Surgical Procedures ; China ; Consensus ; Sinusitis/surgery* ; Dermal Fillers

Limb dismemberment injuries are common in clinical practice,and safe and effective protection of the dismembered limb is the key to successful limb replantation.Normothermic machine perfusion has made significant breakthrough in the field of organ transplantation,which may maintain the active function of organs and tissues for a long period of time and prolong the preservation time.These findings have been validated in large animal models and clinical trials.Meantime,this technology is expected to provide novel reference for the preservation and functional recovery of severed limbs.Therefore,this paper reviews the problems of static cold preservation in the preservation of disarticulated limbs,the development history of mechanical perfusion,the current status of clinical application of ambient mechanical perfusion of disarticulated limbs as well as the problems to be solved,and looks forward to the direction of its development and the prospect of its clinical application,with a view to promoting the wide application of this technology in the clinic.

Objective:To study the in vitro construction of functional and self-renewing cartilage organoids based on cartilage acellular extracellular matrix (ECM) microcarriers.Methods:Fresh porcine articular cartilage was taken. The merely crushed cartilage particles were set as natural cartilage group and ECM microcarriers of appropriate particle size, which were prepared by the acellular method of combining physical centrifugation and chemical extraction, were set as microcarrier group. Cartilage organoids were constructed by loading human umbilical cord mesenchymal stem cells (hUCMSCs) and human chondrocytes (hCho) with a ratio of 3∶1 with microcarriers through a rotating bioreactor. The organoids with different induction times were divided into 0-, 7-, 14-, and 21-day induction groups. The cell residues of the microcarrier group and natural cartilage group were evaluated by 4′, 6-diaminidine 2-phenylindole (DAPI) fluorescence staining and DNA quantitative analysis. The retention of microcarrier components was observed by Safranin O and toluidine blue stainnings, and the collagen and glycosaminoglycan (GAGs) levels in the microcarrier group and the natural cartilage group were determined by colorimetric method and dimethyl-methylene blue (DMMB) method. The microcarriers were further characterized by scanning electron microscopy and energy dispersive spectroscopy. The hUCMSCs cultured with Dulbecco′s Modified Eagle′s Medium (DMEM) supplemented with fetal bovine serum (FBS) in a volume fraction of 10% was used as the control group and the hUCMSCs cultured with the microcarrier extract was used as the experimental group. Subgroups of hUCMSCs cultured at 3 time points: 1, 3 and 5 days were set up in the two groups separately. Cell Counting Kit 8 (CCK-8) was used to detect the biocompatibility of the two groups. The cellular activity of the organoids of the 0-, 7-, 14-, and 21-day induction groups was detected by live/dead staining and the self-renewal ability of the cartilage organoids of the 14-day induced group was identified by Ki67 fluorescence staining. The organoids of the 7-, 14-, and 21-day induction groups were detected by RT-PCR in terms of the expression levels of chondrogenesis-related marker aggrecan (ACAN), type II collagen (COL2A1), SRY-related high mobility group-box gene-9 (SOX9), cartilage hypertrophy-and mineralization-related marker type I collagen (COL1A1), Runt-related transcription factor-2 (RUNX2), and osteocalcin (OCN). Colorimetric and DMMB assays were performed to determine the ability of organoids in the 0-, 7-, 14-, and 21-day induction groups to secrete collagen and GAGs.Results:The results of DAPI fluorescent staining showed that the natural cartilage group had a large number of nuclei while the microcarrier group hardly had any nuclei. The DNA content of the microcarrier group was (7.8±1.8)ng/mg, which was significantly lower than that of the natural cartilage group [(526.7±14.7)ng/mg] ( P<0.01). Saffranin O and toluidine blue staining showed that the microcarrier was dark- and uniform-colored and it kept a lot of cartilage ECM components. The collagen and GAGs contents of the microcarrier group were (252.9±1.4)μg/mg and (173.4±0.8)μg/mg, which were significantly lower than those of the natural cartilage group [(311.9±2.2)μg/mg and (241.3±0.7)μg/mg] ( P<0.01). Scanning electron microscopy showed that the surface of the microcarriers had uneven and interleaved collagen fiber network. The results of energy spectrum analysis showed that elements C, O and N were evenly distributed in the microcarriers, indicating that the composition of the microcarrier was uniform. The microcarrier had good biocompatibility and there was no statistical significance in the results of CCK-8 test between the control group and the experimental group after 1 and 3 days of culture ( P>0.05). After 5 days of culture, the A value of the experimental group was 0.53±0.02, which was better than that of the control group (0.44±0.03) ( P<0.05). In the 0-, 7-, 14-, and 21-day induction groups, hUCMSCs and hCho were attached to the surface of the microcarriers, with good cellular activity, and the live/death rates were (70.6±1.1)%, (80.5±0.6)%, (94.5±0.9)%, and (90.8±0.5)% respectively ( P<0.01). There were a large number of Ki67 positive cells in cartilage organoids. RT-PCR showed that the expression levels of ACAN, COL2A1, SOX9, COL1A1, RUNX2 and OCN were 1.00±0.09, 1.00±0.24, 1.00±0.18, 1.00±0.03, 1.00±0.06 and 1.00±0.13 respectively in the 7-day induction group; 4.16±0.28, 5.09±1.25, 5.65±1.05, 0.47±0.01, 1.68±0.02 and 0.21±0.06 respectively in the 14-day induction group; 13.42±0.92, 3.07±0.21, 1.84±1.08, 2.72±0.17, 2.91±0.18 and 3.32±1.20 respectively in the 21-day induction group. Compared with the 7-day induction group, the expression levels of ACAN, COL2A1, SOX9 and RUNX2 in the 14-day group were increased ( P<0.05), but COL1A1 expression level was decreased ( P<0.05), with no significant difference in OCN expression level ( P>0.05). Compared with the 7-day induction group, the expression levels of ACAN, COL1A1 and RUNX2 in the 21-day induction group were significantly increased ( P<0.01), with no significant differences in the expression levels of COL2A1, SOX9 and OCN ( P>0.05). Compared with the 14-day induction group, the expression levels of ACAN, COL1A1, RUNX2 and OCN in the 21-day group were increased ( P<0.05 or 0.01), with no significant difference in the expression level of COL2A1 ( P>0.05), but the expression level of SOX9 was decreased ( P<0.05). The contents of collagen in 0-, 7-, 14-and 21-day induction groups were (219.15±0.48)μg/mg, (264.07±1.58)μg/mg, (270.83±0.84)μg/mg and (280.01±0.48)μg/mg respectively. The GAGs contents were (171.18±1.09)μg/mg, (184.06±1.37)μg/mg, (241.08±0.84)μg/mg and (201.14±0.17)μg/mg respectively. Compared with the 0-day induction group, the contents of collagen and GAGs in 7-, 14-, and 21-day induction groups were significantly increased ( P<0.01), among which the content of collagen was the lowest in 7-day induction group ( P<0.01) but the highest in the 21-day induced group ( P<0.01); the content of GAGs was the lowest in the 7-day induced group ( P<0.01) but the highest in the 14-day induction group ( P<0.01). Conclusions:The microcarriers prepared by combining physical and chemical methods are decellularized successfully, with more matrix retention, uniform composition and on cytotoxicity. By loading microcarriers with hUCMSCs and hCho, cartilage organoids are successfully constructed in vitro, which are characterized by good cell activity, self-renewal ability, strong expression of genes related to chondrogenesis and secretion of collagen and GAGs. The cartilage organoids constructed at 14 days of induction have the best chondrogenic activity.

BACKGROUND:Compared with traditional two-dimensional culture,three-dimensional microtissue culture can show greater advantages.However,more favorable cultivation methods in three-dimensional culture still need to be further explored. OBJECTIVE:To evaluate the cell behavior of microtissue and its ability to promote cartilage formation under two three-dimensional culture methods. METHODS:Cartilage-derived microcarriers were prepared by chemical decellularization and tissue crushing.DNA quantification and nuclear staining were used to verify the success of decellularization,and histological staining was used to observe the matrix retention before and after decellularization.The microcarriers were characterized by scanning electron microscopy and CCK-8 assay.Cartilage-derived microtissues were constructed by combining cartilage-derived microcarriers with human adipose mesenchymal stem cells through three-dimensional static culture and three-dimensional dynamic culture methods.The cell viability and chondrogenic ability of the two groups of microtissues were detected by scanning electron microscopy,live and dead staining,and RT-qPCR. RESULTS AND CONCLUSION:(1)Cartilage-derived microcarriers were successfully prepared.Compared with before decellularization,the DNA content significantly decreased after decellularization(P<0.001).Scanning electron microscope observation showed that the surface of the microcarrier was surrounded by collagen,maintaining the characteristics of the natural extracellular matrix of cartilage cells.CCK-8 assay indicated that microcarriers had no cytotoxicity and could promote cell proliferation.(2)Scanning electron microscopy and live and dead staining results showed that compared with the three-dimensional static group,the three-dimensional dynamic group had a more extended morphology of microtissue cells,and extensive connections between cells and cells,between cells and matrix,and between matrix.(3)The results of RT-qPCR showed that the expressions of SOX9,proteoglycan,and type Ⅱ collagen in microtissues of both groups were increased at 7 or 14 days.The relative expression levels of each gene in the three-dimensional dynamic group were significantly higher than those in the three-dimensional static group at 14 days(P<0.05).At 21 days,the three-dimensional static group had significantly higher gene expression compared with the three-diomensional dynamic group(P<0.001).(4)The results showed that compared with three-dimensional static culture microtissue,three-dimensional dynamic culture microtissue could achieve higher expression of chondrogen-related genes in a shorter time,showing better cell viability and chondrogenic ability.

Objective:To construct adjustable stiffness hydrogels based on gelatin methacryloyl (GelMA), in order to better simulate the growth environment under physiological conditions.Methods:SYLGARD 184 silicone rubber was used to prepare adjustable stiffness hydrogels. The stiffness values of the adjustable stiffness hydrogels prepared with GelMA of different grafting rates (30%, 60%, 90%) at various concentrations (5%, 10%, 15%) were quantified using Young’s modulus. Based on the result, the optimal grafting rate GelMA was selected as the material for constructing the adjustable stiffness hydrogels. The relationship between the concentration (2%, 3%, 5%, 6%, 8%, 10%, 15%) of 90% grafting rate (GM90) and the stiffness after photopolymerization was determined by measuring the Young’s modulus of GelMA at different concentrations and fitting the data. Three groups of suitable concentrations were chosen to construct three different stiffness hydrogels. After soaking in phosphate-buffered saline for 48 hours, various samples underwent biomechanical measurements, internal pore structure observation, atomic force microscopy to measure parameters such as Young’s modulus, pore size and surface roughness. Rheological tests were carried out, curves were drawn according to the energy storage modulus and loss modulus, and shear frequencies of the intersection points of the two curves were observed at each concentration to evaluate the ability of hydrogel to maintain its morphology. Data analysis was performed using GraphPad Prism 8.0.2 software. Quantitative data were expressed as Mean±SD, and one-way ANOVA was used for comparison among multiple groups, and LSD method was used for pairwise comparison. Statistical significance was set at P<0.05. Results:Increasing the grafting rate and concentration of GelMA hydrogels effectively enhanced their stiffness. GelMA with a GM90 provided a broader range of stiffness, making it suitable for constructing the adjustable stiffness hydrogels. Fitting curves of GM90 concentrations and stiffness after photopolymerization showed that at concentrations of 2%, 6%, and 15%, GelMA could mimic the stiffness of various tissues of human. Therefore, these three concentrations were selected for subsequent experiments. The Young’s modulus of GM90 at concentrations of 15%, 6% and 2% were (98.43±7.71), (14.57±1.62), and (2.11±0.32) kPa, respectively, with statistically significant differences between each pair of groups ( P<0.01). The pore sizes were (41.32±3.51), (3.26±0.33), and (1.21±0.11) μm, respectively, showing significant differences between each pair of groups ( P<0.01). Surface roughness values were (48.15±2.65), (22.65±1.78), and (24.12±1.43) nm, respectively, with 15% concentration showing significantly higher roughness than the 2% and 6% concentrations ( P<0.01), while there was no significant difference between the 2% and 6% concentrations ( P>0.05). Rheological testing indicated that as the concentration decreased, the shear frequency at the crossover point of the storage modulus and loss modulus of GM90 hydrogels decreased, >100, 30 and 18 Hz, respectively. The result showed that the solid form of GM90 hydrogel with 15% concentration was more stable, while the hydrogel with 2% concentration had better fluidity. Conclusion:Adjusting the grafting rate and concentration can regulate the stiffness of GelMA hydrogels. GelMA hydrogels with a 90% grafting rate provide a wide range of stiffness, making them ideal materials for constructing hydrogels with adjustable stiffness. At concentrations of 2%, 6%, and 15%, GM90 exhibited different mechanical properties and internal structures.

Objective:To construct adjustable stiffness hydrogels based on gelatin methacryloyl (GelMA), in order to better simulate the growth environment under physiological conditions.Methods:SYLGARD 184 silicone rubber was used to prepare adjustable stiffness hydrogels. The stiffness values of the adjustable stiffness hydrogels prepared with GelMA of different grafting rates (30%, 60%, 90%) at various concentrations (5%, 10%, 15%) were quantified using Young’s modulus. Based on the result, the optimal grafting rate GelMA was selected as the material for constructing the adjustable stiffness hydrogels. The relationship between the concentration (2%, 3%, 5%, 6%, 8%, 10%, 15%) of 90% grafting rate (GM90) and the stiffness after photopolymerization was determined by measuring the Young’s modulus of GelMA at different concentrations and fitting the data. Three groups of suitable concentrations were chosen to construct three different stiffness hydrogels. After soaking in phosphate-buffered saline for 48 hours, various samples underwent biomechanical measurements, internal pore structure observation, atomic force microscopy to measure parameters such as Young’s modulus, pore size and surface roughness. Rheological tests were carried out, curves were drawn according to the energy storage modulus and loss modulus, and shear frequencies of the intersection points of the two curves were observed at each concentration to evaluate the ability of hydrogel to maintain its morphology. Data analysis was performed using GraphPad Prism 8.0.2 software. Quantitative data were expressed as Mean±SD, and one-way ANOVA was used for comparison among multiple groups, and LSD method was used for pairwise comparison. Statistical significance was set at P<0.05. Results:Increasing the grafting rate and concentration of GelMA hydrogels effectively enhanced their stiffness. GelMA with a GM90 provided a broader range of stiffness, making it suitable for constructing the adjustable stiffness hydrogels. Fitting curves of GM90 concentrations and stiffness after photopolymerization showed that at concentrations of 2%, 6%, and 15%, GelMA could mimic the stiffness of various tissues of human. Therefore, these three concentrations were selected for subsequent experiments. The Young’s modulus of GM90 at concentrations of 15%, 6% and 2% were (98.43±7.71), (14.57±1.62), and (2.11±0.32) kPa, respectively, with statistically significant differences between each pair of groups ( P<0.01). The pore sizes were (41.32±3.51), (3.26±0.33), and (1.21±0.11) μm, respectively, showing significant differences between each pair of groups ( P<0.01). Surface roughness values were (48.15±2.65), (22.65±1.78), and (24.12±1.43) nm, respectively, with 15% concentration showing significantly higher roughness than the 2% and 6% concentrations ( P<0.01), while there was no significant difference between the 2% and 6% concentrations ( P>0.05). Rheological testing indicated that as the concentration decreased, the shear frequency at the crossover point of the storage modulus and loss modulus of GM90 hydrogels decreased, >100, 30 and 18 Hz, respectively. The result showed that the solid form of GM90 hydrogel with 15% concentration was more stable, while the hydrogel with 2% concentration had better fluidity. Conclusion:Adjusting the grafting rate and concentration can regulate the stiffness of GelMA hydrogels. GelMA hydrogels with a 90% grafting rate provide a wide range of stiffness, making them ideal materials for constructing hydrogels with adjustable stiffness. At concentrations of 2%, 6%, and 15%, GM90 exhibited different mechanical properties and internal structures.

Objective To propose a deep learning neural network approach for transforming megavoltage computed tomography(MVCT)images of cervical cancer into pseudo kilovoltage computed tomography(kVCT)images with high signal-to-noise ratio and contrast-to-noise ratio,thus providing three-dimensional anatomical images and localization information required for adaptive radiotherapy of cervical cancer,and guiding the accelerator to achieve precise treatment.Methods The MVCT and kVCT images of 54 patients treated with cervical cancer radiotherapy were collected,with 44 cases randomly selected as the training set,and the remaining 10 cases as the test set.A cyclic generative adversarial network with gating mechanism and multi-channel data input was used to synthesize pseudo-kVCT images from MVCT images.The network training results were evaluated with imaging quality evaluation parameters,such as mean absolute error(MAE),peak signal-to-noise ratio(PSNR),and structural similarity index(SSIM).Results The MAE,PSNR,and SSIM of MVCT imagesvspseudo-kVCT(5:5)images were(24.9±0.7)HUvs(17.8±0.3)HU,(29.8±0.2)dBvs(30.7±0.2)dB,and 0.841±0.007 vs 0.898±0.003,respectively.Conclusion The generated pseudo-kVCT images have advantages in noise reduction and contrast enhancement,and can reduce the need for additional MV-kVCT electron density calibration in dose calculations.The dose calculation ability of pseudo-kVCT is comparable to that of MVCT,providing a possibility for the application of pseudo-kVCT images in image-guided adaptive radiotherapy.

Objective:To evaluate the pin-bone interface surface culture in the diagnosis of pin tract infection in external fixation.Methods:A prospective observational study was conducted to enroll the patients who underwent either partial or complete removal of external fixators after external fixation at Department of Orthopaedic Trauma, Nanfang Hospital, Southern Medical University from June 2023 to September 2023. The secretions from the pin track (pin-soft tissue interface) were plated for bacterial culture. Additionally, the surface of the pins placed within the bone (pin-bone interface) was cultured directly with tryptic soy agar (TSA). Positive cases were subjected to additional analysis using qualitative microbial culture and antibiotic susceptibility testing. Comparisons were made between the cultural results derived from both interfaces.Results:The present study enrolled 23 patients [18 males and 5 females with an age of (37.3±17.6) years] and a duration of bearing external fixation of 8.1 (4.0, 11.3) months. A total of 212 samples were cultured. The positive rate of bacterial culture at the pin-soft tissue interface was 53.8% (57/106), significantly higher than that at the pin-bone interface [17.9% (19/106)] ( P<0.05). No correlation was found in the results of bacterial culture between the pin-bone interface and the pin-soft tissue interface ( r=-0.011, P=0.913). In terms of bacterial strains, single pathogenic bacteria were found in all the 19 positive samples cultured at the pin-bone interface, with Staphylococcus aureus as the most common pathogenic bacteria (7); of the 57 positive samples cultured at the pin-soft tissue interface, single pathogen infection was found in 51 and mixed bacterial infection in 6. Positive culture was found at both interfaces in 10 samples, of which identical bacterial strains were found in 4 and partially identical bacterial strains in 1. A total of 82 bacterial samples were subjected to drug sensitivity testing, of which 74.4% (61/82) were infected with Staphylococcus. The drug sensitivity test of Staphylococcus showed that the top 3 resistant drugs were ampicillin, oxacillin, and penicillin. The top 3 sensitive drugs were vancomycin, teicoplanin, and linezolid, all of which showed little resistance. Conclusions:Pin-bone interface culture of external fixators is a necessary evaluation of the infection of deep bone tissue. Simultaneous culture of pin-bone interface and pin-soft tissue interface can provide more comprehensive basis for the treatment of pin tract infection.

Objective:To investigate the effects of ovarian cancer domain containing protease-1 (OTUD1) gene on the typeⅠ interferon signaling pathway, and its impact on the antiviral effects of IFN-α.Methods:Dual-luciferase reporter assay was performed to detect the effects of OTUD1 gene on the transcriptional activity of interferon-stimulated response element (ISRE) promoter. Quantitative real-time PCR (qPCR) was used to detect the effects of OTUD1 on IFN-α-induced expression of interferon-stimulated genes (ISGs). The effects of OTUD1 gene on the expression of key proteins in the IFN-α signal transduction pathway were analyzed by Western blot, and its effects on IFN-α-mediated inhibition of hepatitis B virus replication were detected by qPCR and ELISA.Results:In HEK293T and Huh7.0 cells, OTUD1 down-regulated the transcriptional activity of ISRE promoter in the interferon signaling pathway and the expression of antiviral genes such as ISG15 and ISG56. In HEK293T cells, OTUD1 reduced the expression of phospho-Jak1 (p-JAK1) at protein level, but the catalytic inactive mutant of OTUD1 (C320S) could not regulate the expression of ISGs or p-JAK1. In Huh7.0 cells, OTUD1 antagonized the inhibitory effect of IFN-α on hepatitis B virus replication.Conclusions:OTUD1 with the ubiquitination activity can inhibit the interferon JAK-STAT signaling pathway and the expression of ISGs by down-regulating the expression of p-JAK1 protein. OTUD1 antagonizes the effect of IFN-α on viral replication and that may be related to the interferon-induced JAK-STAT signaling pathway.