Exosomes from chondrocytes overexpressing miR-214-3p facilitate M2 macrophage polarization and angiogenesis to relieve Legg Calvé-Perthes disease.

OBJECTIVE: Legg-Calvé-Perthes disease (LCPD) is a partial or total necrosis of femoral head bone caused by blood supply disorder and its etiology is not clear. Studies have revealed that microRNA-214-3p (miR-214-3p) plays a vital role in LCPD, however, its exact mechanism is still unclear. In this study, we investigated the potential role of chondrocytes-derived exosomes carrying miR-214-3p (exos-miR-214-3p) in the pathogenesis of LCPD. METHODS: RT-qPCR was performed to evaluate miR-214-3p expression level in femoral head cartilage, serum and chondrocytes of patients with LCPD, as well as dexamethasone (DEX)-exposed TC28 cells. Effects of exos-miR-214-3p on the proliferation and apoptosis were verified via MTT assay, TUNEL staining and caspase3 activity assay. The M2 macrophage markers were assessed by flow cytometry, RT-qPCR and Western blot. Moreover, angiogenic effects of human umbilical vein endothelial cells (HUVECs) were tested using CCK-8 and tube formation assays. Bioinformatics prediction, luciferase assay and ChIP were applied to verify the association between ATF7, RUNX1 and miR-214-3p. RESULTS: miR-214-3p was found to be decreased in patients with LCPD and DEX-treated TC28 cells, of which overexpression promoted cell proliferation and suppressed apoptosis. Mechanistically, exos-miR-214-3p facilitated M2 polarization by ATF7/TLR4 axis and HUVECs angiogenesis via RUNX1/VEGFA axis. CONCLUSION: miR-214-3p alleviates LCPD by promoting M2 polarization of macrophages and angiogenesis.

Arginine metabolism governs microcycle conidiation by changing nitric oxide content in Metarhizium acridum.

Microcycle conidiation commonly exists in filamentous fungi and has great potential for mass production of mycoinsecticides. L-Arginine metabolism is essential for conidiation and conditional growth and virulence, but its role in microcycle conidiation has not been explored. Here, a unique putative arginase (MaAGA) was characterized in the entomopathogenic fungus Metarhizium acridum. Conidial germination and thermotolerance were facilitated by the disruption of MaAGA. Despite little impact on fungal growth and virulence, the disruption resulted in normal conidiation after a 60-h incubation on microcycle conidiation medium (SYA) under normal culture conditions. In the MaAGA-disruption mutant (ΔMaAGA), intracellular arginine accumulation was sharply increased. Replenishment of the direct metabolites of arginase, namely ornithine and/or urea, was unable to restore the disruption mutant's microcycle conidiation on SYA. Interestingly, nitric oxide synthase (NOS) activity and nitric oxide (NO) levels of the ΔMaAGA strain were markedly decreased in the 60-h-old SYA cultures. Finally, adding Nω-nitro-L-arginine, an inhibitor of NOS, into the SYA converted the microcycle conidiation of the wild-type strain to normal conidiation. In contrast, adding sodium nitroprusside, an NO donor, into the SYA recovered the mutant's microcycle conidiation. The results indicate that arginine metabolism controls microcycle conidiation by changing the content of NO. KEY POINTS: • The MaAGA-disruption led to normal conidiation on microcycle conidiation medium SYA. • Nitric oxide (NO) level of the ΔMaAGA strain was markedly decreased. • Adding an NO donor into the SYA recovered the microcycle conidiation of ΔMaAGA.

Associations between velamentous or marginal cord insertion and risk of adverse perinatal outcomes in twin pregnancies: a retrospective cohort study.

BACKGROUND: Velamentous cord insertion (VCI) and marginal cord insertion (MCI) are well-known risk factors for adverse perinatal outcomes in singleton pregnancies. However, the potential links between VCI or MCI and perinatal outcomes in twin pregnancies have yet to be systematically evaluated. This study aimed to investigate the relationships between VCI or MCI and perinatal outcomes in twin pregnancies. METHODS: This retrospective single-center cohort study included women with twin pregnancies who gave birth in a tertiary hospital in Southwest, China between January 2017 and December 2022. VCI and MCI were identified by abdominal ultrasound and confirmed after placental delivery. Logistic regression, multinomial logit regression and generalized estimation equation models were used to evaluate the association between VCI or MCI and perinatal outcomes. RESULTS: A total of 3682 twin pregnancies were included, including 100 (2.7%) pregnancies with VCI and 149 (4.0%) pregnancies with MCI. Compared to pregnancies with normal cord insertion, both monochorionic and dichorionic pregnancies with VCI were associated with an increased risk of preterm delivery 32-34 weeks (aRRR 2.94, 95% CI 1.03-8.39; aRRR 2.55, 95% CI 1.19-5.46, respectively), while pregnancies with MCI were not associated with preterm delivery. VCI was associated with a higher incidence of placental previa (aOR 6.36, 95% CI 1.92-21.04) in monochorionic pregnancies and placental accreta (aOR 1.85, 95% CI 1.06-3.23) in dichorionic pregnancies. MCI was associated with an increased risk of preeclampsia (aOR 3.07, 95% CI 1.49-6.32), intertwin birthweight discordance ≥ 20% (aOR 2.40, 95% CI 1.08-5.60) and selective fetal growth restriction (aOR 2.46, 95% CI 1.08-5.60) in monochorionic pregnancies and small-for-gestational age neonates (aOR 1.97, 95% CI 1.24-3.14) in dichorionic pregnancies. CONCLUSIONS: VCI was associated with an increased risk of preterm delivery in twin pregnancies irrespective of chorionicity, whereas MCI was associated with an increased preeclampsia risk, significant intertwin birthweight discordance in monochorionic pregnancies and small-for-gestational age neonates in dichorionic pregnancies.

Evaluation of herb-drug interaction of ambrisentan with shikonin based on UPLC-MS/MS.

CONTEXT: Ambrisentan is an oral endothelin-receptor antagonist (ERA). However, there is no report on the interaction between ambrisentan and shikonin. OBJECTIVE: To investigate the effect of shikonin on ambrisentan metabolism in vivo and in vitro. MATERIALS AND METHODS: This study developed an ultra-performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) method for simultaneous determination of ambrisentan and (S)-4-hydroxymethyl ambrisentan in rat plasma. Twelve male Sprague-Dawley (SD) rats were divided into two groups (n = 6): the control group and shikonin (20 mg/kg) group. The pharmacokinetics of ambrisentan (2.5 mg/kg) were investigated after 30 min. Additionally, human and rat liver microsomes were used to investigate the herb-drug interaction. RESULTS: The UPLC-MS/MS method was shown to be accurate, precise and reliable, and was successfully applied to the herb-drug interaction study of ambrisentan with shikonin. When co-administrated with 20 mg/kg shikonin, the Cmax and AUC(0-∞) of ambrisentan were significantly increased by 44.96 and 16.65%, respectively (p < 0.05). In addition, there were modest decreases in (S)-4-hydroxymethyl ambrisentan Cmax and AUC(0-∞) in the presence of shikonin (p < 0.05), which indicated that these results were in accordance with the inhibition of shikonin on ambrisentan metabolism. Moreover, enzyme kinetic study indicated that shikonin had an inhibitory effect on human and rat microsomes where the IC50 values of shikonin were 5.865 and 6.358 µM, respectively. CONCLUSIONS: Our study indicated that shikonin could inhibit ambrisentan metabolism. Further studies need to be carried out to verify whether similar interaction truly apply in humans and whether this interaction has clinical significance.

Comparative study of lateral condyle fracture with or without posteromedial elbow dislocation in children.

PURPOSE: The purpose of this study was to compare the surgical findings and clinical outcomes of the lateral condylar fractures of the humerus with or without posteromedial elbow dislocation in children. METHODS: Between January 2013 and June 2016, a total of 21 Milch type II humeral condylar fractures were treated with open reduction and internal fixation. The average follow-up was 2.8 years (range, 1 to 4 years). There were 8 patients in group A with posteromedial elbow dislocation and 13 patients in group B without dislocation. The surgical findings, bone union time, the recovery of function, and the time needed to regain full range of elbow movement were all compared. The complications encountered during operation and follow-up were documented. RESULTS: Surgical findings showed that all the fracture lines in group A extended to the lower medial part of the trochlea. The fracture lines in group B only involved the lateral and middle part of the trochlea. There were no significant differences in bone union time between the two groups. The time needed to regain full range of elbow movement after operation in group A (21 ± 4.0 weeks) was significantly longer in group B (17.85 ± 2.51 weeks; P < 0.05). There were no significant differences in MEPS, the flexion-extension arc, and the total range of flexion and extension between the two groups (P < 0.05).There was no difference in complications between the two groups (P < 0.05). CONCLUSION: The fracture lines in Milch type II fractures of lateral humeral condyle with concomitant posteromedial elbow dislocation extend to the lower medial part of the trochlea. The soft tissue injuries are more badly so that longer time needed to regain full range of elbow movement. Initial recognition of this rare injury is essential to regain satisfactory functional outcomes.

Synthesis of Halide-Modulated Cuprous(I) Coordination Polymers with Mechanochromic and Photocatalytic Properties.

Two copper(I) halide-based coordination polymers, namely, [Cu3Cl2(Tipa)2]Cl (1, (Tipa = tris(4-(1H-imidazol-1-yl)phenyl)amine) and [Cu3I3(CuI)2(Tipa)3] (2), were obatined under the solvothermal reactions, respectively. Compound 1 with the chain structure shows unique Cu···Cu interactions, C-H···Cl halogen hydrogen bonds, and π···π stacking interactions. It also exhibits unusual mechanochromic and photocatalytic properties on degradation of methylene blue (MB).

[Chemical Constituents from Cynomorium songaricum].

Objective: To study the chemical constituents from the fleshy stems of Cynomorium songaricum. Methods: The chemical constituents were isolated and purified by chromatography on MCI, silica gel, Sephadex LH-20 columns, etc. The structures of compounds were elucidated by physicochemical property and spectral analyses. Results: 15 compounds were isolated and identified as choerospondin( 1), isolariciresinol-4-O-ß-D-glucopyranoside( 2), lutelin-7-O-ß-D-glucopyranoside( 3), 3, 4-dihydroxyphenethylacetate( 4),maslinic acid( 5),catechin ( 6),ursolic acid( 7),gentisic acid( 8),mannitol( 9), phloroglucinol( 10), ß-sitosterol( 11), daucosterol( 12), rutin( 13), cetylic acid( 14) and epicatechin( 15). Conclusion: Compounds 4,5,8,9 and 10 are obtained from this plant for the first time.

Improvement in angiogenesis and osteogenesis with modified cannulated screws combined with VEGF/PLGA/fibrin glue in femoral neck fractures.

Angiogenesis is essential for bone healing. Vascular endothelial growth factor (VEGF) is regarded as one of the most potent antigenic cytokines; however, there have been very few studies that have previously investigated the effects of VEGF on bone healing in a femoral neck fracture model. Thus, the aim of the present study was to test both the angiogenic and osteogenic properties of a VEGF/poly-lactic acid glycolic acid (PLGA) delivery system for the treatment of femoral neck fractures. VEGF/PLGA microspheres were prepared by the double emulsion solvent-evaporation method and in vitro VEGF release was quantified by an ELISA assay. Then the preparation of femoral neck fracture model and internal fixation were performed, and the effect of the VEGF/PLGA microspheres on bone healing was determined by X-ray, radionuclide bone scanning, and histomorphometric evaluation. The release of VEGF from the VEGF/PLGA microspheres was sustained for at least 42 days in vitro, and suspension of the delivery system in fibrin glue further slowed this VEGF release rate. In dogs, revascularization of the fractured femoral heads was significantly improved by a local injection of VEGF/PLGA/fibrin glue, and the quality and speed of fracture healing were significantly improved in the Experimental group than in the Control group. Our study confirmed that the VEGF/PLGA delivery system offers good angiogenic and osteogenic properties for the treatment of canine femoral neck fractures.

Construction and validation of a novel NAD+ metabolism-related risk model for prognostic prediction in osteosarcoma.

Currently, the prognosis of osteosarcoma (OS) remains discouraging, especially in elderly/metastatic OS patients. By impairing the antitumor effect of immune cells, tumor immune microenvironment (TIME) provides an environment conducive to tumor proliferation, which highly requires accelerated nicotinamide adenine dinucleotide (NAD+) metabolism for energy. Recently, many genes involved in the sustained production of NAD+ in malignant tumors have been verified to be possible prognostic indicators and therapeutic targets. Therefore, the current study was to probe into the association of NAD+ metabolism-related genes with TIME, immunotherapeutic response, and prognosis in OS. All OS data for the study were acquired from TARGET and GEO databases. In bioinformatics analysis, we performed Cox analysis, consensus clustering, principal component analysis, t-distributed stochastic neighbor embedding, uniform manifold approximation and projection, gene set enrichment analysis, gene set variation analysis, Lasso analysis, survival and ROC curves, nomogram, immune-related analysis, drug sensitivity analysis, and single-cell RNA sequencing (scRNA-seq) analysis. Cell transfection assay, RT-qPCR, western blot analysis, as well as cell wound healing, migration, and invasion assays were performed in vitro. Bioinformatics analysis identified A&B clusters and six NAD+ metabolism-related differentially expressed genes, constructed risk model and nomogram, and performed immune-related analysis, drug susceptibility analysis, and scRNA-seq analysis to inform the clinical treatment framework. In vitro experiment revealed that CBS and INPP1 can promote migration, proliferation as well as invasion of OS cells through TGF-ß1/Smad2/3 pathway. Based on bioinformatics analysis and in vitro validation, this study confirmed that NAD+ metabolism affects TIME to suggest the prognosis of OS.

Quality assessment of videos on social media platforms related to gestational diabetes mellitus in China: A cross-section study.

Purpose: This study aimed to systematically evaluate the quality of content and information in videos related to gestational diabetes mellitus on Chinese social media platforms. Methods: The videos on various platforms, TikTok, Bilibili, and Weibo, were searched with the keyword "gestational diabetes mellitus" in Chinese, and the first 50 videos with a comprehensive ranking on each platform were included for subsequent analysis. Characteristic information of video was collected, such as their duration, number of days online, number of likes, comments, and number of shares. DISCREN, JAMA (The Journal of the American Medical Association) Benchmark Criteria, and GQS (Global Quality Scores) were used to assess the quality of all videos. Finally, the correlation analysis was performed among video features, video sources, DISCERN scores, and JAMA scores. Results: Ultimately, 135 videos were included in this study. The mean DISCERN total score was 31.84 ± 7.85, the mean JAMA score was 2.33 ± 0.72, and the mean GQS was 2.00 ± 0.40. Most of the videos (52.6%) were uploaded by independent medical professionals, and videos uploaded by professionals had the shortest duration and time online (P < 0.001). The source of the video was associated with numbers of "likes", "comments", and "shares" for JAMA scores (P < 0.001), but there was no correlation with DISCERN scores. Generally, videos on TikTok with the shortest duration received the most numbers of "likes", "comments", and "shares", but the overall quality of videos on Weibo was higher. Conclusion: Although the majority of the videos were uploaded by independent medical professionals, the overall quality appeared to be poor. Therefore, more efforts and actions should be taken to improve the quality of videos related to gestational diabetes mellitus.

Global research on emerging trends of obstetrics during the COVID-19 pandemic: A bibliometric analysis.

Coronavirus disease-2019 (COVID-19) has caused continuous effects on the global public, especially for susceptible and vulnerable populations like pregnant women. COVID-19-related studies and publications have shown blowout development, making it challenging to identify development trends and hot areas by using traditional review methods for such massive data. Aimed to perform a bibliometric analysis to explore the status and hotspots of COVID-19 in obstetrics. An online search was conducted in the Web of Science Core Collection (WOSCC) database from January 01, 2020 to November 31, 2022, using the following search expression: (((TS= ("COVID 19" OR "coronavirus 2019" OR "coronavirus disease 2019" OR "SARS-CoV-2" OR "2019-nCoV" OR "2019 novel coronavirus" OR "SARS coronavirus 2" OR "Severe Acute Respiratory Syndrome Coronavirus-2" OR "SARS-COV2")) AND TS= ("obstetric*" OR "pregnancy*" OR "pregnant" OR "parturition*" OR "puerperium"))). VOSviewer version 1.6.18, CiteSpace version 6.1.R6, R version 4.2.0, and Rstudio were used for the bibliometric and visualization analyses. 4144 articles were included in further analysis, including authors, titles, number of citations, countries, and author affiliations. The United States has contributed the most significant publications with the leading position. "Sahin, Dilek" has the largest output, and "Khalil, Asma" was the most influential author with the highest citations. Keywords of "Cov," "Experience," and "Neonate" with the highest frequency, and "Systematic Review" might be the new research hotspots and frontiers. The top 3 concerned genes included ACE2, CRP, and IL6. The new research hotspot is gradually shifting from the COVID-19 mechanism and its related clinical research to reviewing treatment options for pregnant women. This research uniquely delves into specific genes related to COVID-19's effects on obstetrics, a focus that has not been previously explored in other reviews. Our research enables clinicians and researchers to summarize the overall point of view of the existing literature and obtain more accurate conclusions.

A nomogram for predicting the risk of preeclampsia in women with intrahepatic cholestasis of pregnancy based on prenatal monitoring time: a multicenter retrospective cohort study.

BACKGROUND AND AIMS: Intrahepatic cholestasis of pregnancy (ICP) is a special liver disease during pregnancy, characterized by abnormal bile acid metabolism. However, there is no consensus on how to group women with ICP based on the time of diagnosis worldwide. This study aimed to adopt a new grouping model of women with ICP, and the time from diagnosis to delivery was defined as the monitoring period. METHODS: This retrospective real-world data study was conducted across multiple centers and included 3172 women with ICP. The study first evaluated the significant difference in medication and nonmedication during different monitoring times. The least absolute shrinkage and selection operator (LASSO) model was then used to screen nine risk factors based on the predictors. The model's discrimination, clinical usefulness, and calibration were assessed using the area under the receiver operating characteristic (ROC) curve, decision curve, and calibration analysis. RESULTS: The incidence of preeclampsia risk in ICP patients without drug intervention increased with the extension of the monitoring period. However, the risk of preeclampsia decreased in ICP patients treated with ursodeoxycholic acid. A predictive nomogram and risk score model was developed based on nine risk factors. The area under the ROC curve of the nomogram was 0.765 [95% confidence interval (CI): 0.724-0.807] and 0.812 (95% CI: 0.736-0.889) for the validation cohort. CONCLUSIONS: This study found that a longer ICP monitoring period could lead to adverse pregnancy outcomes in the absence of drug intervention, especially preeclampsia. A predictive nomogram and risk score model was developed to better manage ICP patients, maintain pregnancy to term delivery, and minimize the risk of severe adverse maternal and fetal outcomes.

Olanzapine attenuates 5-HT2cR and GHSR1a interaction to increase orexigenic hypothalamic NPY: Implications for neuronal molecular mechanism of metabolic side effects of antipsychotics.

The main cause of second-generation antipsychotic (SGA)-induced obesity is considered due to the antagonism of serotonin 2c receptors (5-HT2cR) and activation of ghrelin receptor type 1a (GHSR1a) signalling. It is reported that 5-HT2cR interacted with GHSR1a, however it is unknown whether one of the SGA olanzapine alters the 5-HT2cR/GHSR1a interaction, affecting orexigenic neuropeptide signalling in the hypothalamus. We found that olanzapine treatment increased average energy intake and body weight gain in mice; olanzapine treatment also increased orexigenic neuropeptide (NPY) and GHSR1a signaling molecules, pAMPK, UCP2, FOXO1 and pCREB levels in the hypothalamus. By using confocal fluorescence resonance energy transfer (FRET) technology, we found that 5-HT2cR interacted/dimerised with the GHSR1a in the hypothalamic neurons. As 5-HT2cR antagonist, both olanzapine and S242084 decreased the interaction between 5-HT2cR and GHSR1a and activated GHSR1a signaling. The 5-HT2cR agonist lorcaserin counteracted olanzapine-induced attenuation of interaction between 5-HT2cR and GHSR1a and inhibited activation of GHSR1a signalling and NPY production. These findings suggest that 5-HT2cR antagonistic effect of olanzapine in inhibition of the interaction of 5-HT2cR and GHSR1a, activation GHSR1a downstream signaling and increasing hypothalamic NPY, which may be the important neuronal molecular mechanism underlying olanzapine-induced obesity and target for prevention metabolic side effects of antipsychotic management in psychiatric disorders.

Gestational diabetes mellitus aggravates adverse perinatal outcomes in women with intrahepatic cholestasis of pregnancy.

PURPOSE: To evaluate the effect of intrahepatic cholestasis of pregnancy (ICP) with gestational diabetes mellitus (GDM) on perinatal outcomes and establish a prediction model of adverse perinatal outcomes in women with ICP. METHODS: This multicenter retrospective cohort study included the clinical data of 2,178 pregnant women with ICP, including 1,788 women with ICP and 390 co-occurrence ICP and GDM. The data of all subjects were collected from hospital electronic medical records. Univariate and multivariate logistic regression analysis were used to compare the incidence of perinatal outcomes between ICP with GDM group and ICP alone group. RESULTS: Baseline characteristics of the population revealed that maternal age (p < 0.001), pregestational weight (p = 0.01), pre-pregnancy BMI (p < 0.001), gestational weight gain (p < 0.001), assisted reproductive technology (ART) (p < 0.001), and total bile acid concentration (p = 0.024) may be risk factors for ICP with GDM. Furthermore, ICP with GDM demonstrated a higher association with both polyhydramnios (OR 2.66) and preterm labor (OR 1.67) compared to ICP alone. Further subgroup analysis based on the severity of ICP showed that elevated total bile acid concentrations were closely associated with an increased risk of preterm labour, meconium-stained amniotic fluid, and low birth weight in both ICP alone and ICP with GDM groups. ICP with GDM further worsened these outcomes, especially in women with severe ICP. The nomogram prediction model effectively predicted the occurrence of preterm labour in the ICP population. CONCLUSIONS: ICP with GDM may result in more adverse pregnancy outcomes, which are associated with bile acid concentrations.

A retrospective study of inpatients diagnosed with degloving skin and soft tissue injuries.

The overall picture of degloving skin and soft tissue injuries (DSTI) remains a blank space in China. Therefore, a retrospective study was designed to summarize the current situation of this injury. Patients diagnosed with DSTI hospitalized between 2013 and 2018 were identified from the Hospital Quality Monitoring System (HQMS) database, of whom demographics, injury characteristics, hospitalization and cost information were analyzed. A total of 62,709 patients were enrolled in this study. Male sex predominated, with a mean age of 43.01 ± 19.70 years. Peasants seemed to be the most vulnerable. East China and Hubei province had the most patients. The most and least frequently injured anatomic site were lower extremity and torso, respectively. Traffic-related accidents and summer accounted for the highest proportion in terms of injury mechanism and season. The operation rate of DSTI roughly showed a growing trend, and the average length of stay was 22.02 ± 29.73 days. At discharge, 0.93% of DSTI patients ended up in death. Medicine accounted mostly for hospitalization cost, while the proportion decreased year by year. More than half DSTI patients paid at their own charge. This study made a relatively detailed description of DSTI patients nationwide, and might provide enlightenments for better prevention and treatment.

S-osteotomy with lengthening and then nailing compared with traditional Ilizarov method.

PURPOSE: The purpose of this study was to explore the clinical effect of the novel method combined longitudinal S-osteotomy and Lengthen And Then Nail (LATN) technique for leg lengthening and compare with the classic Ilizarov method. METHODS: This retrospective study was performed from March 2008 to April 2012. A total of 176 leg lengthenings (88 consecutive patients) were performed at our institution. The mean duration of follow-up was 2.2 years (range, one to four years). In group A, 78 tibial lengthenings were performed with longitudinal S-osteotomy and LATN technique. In group B, 98 tibial lengthenings were performed with the classic method. The final gain in length, mean surgical time for bilateral tibial osteotomy, the external fixation index and the radiographic consolidation index were calculated and compared. The complications encountered during operation and follow-up were documented. RESULTS: There was no significant difference in the final gain in length between the two groups. Mean surgical time in group A (130.05 ± 6.60 min) was significantly longer than that in group B (91.4 ± 6.61 min; P < 0.05). External fixation index in group A (21.02 ± 3.16 days/cm) was significantly lower than that in group B (76.19 ± 8.32 days/cm; P < 0.05). Consolidation index was significantly lower (more rapid healing) in group A (43.38 ± 5.35 days/cm) than that in group B (76.19 ± 8.32 days/cm; P < 0.05). There was a significant difference in pin-tract problems and axial deviation between the two groups. CONCLUSION: The novel method combined longitudinal S-corticotomy and LATN technique safely reduces the consolidation time, rate of pin-tract problems and axial deviation during leg lengthening, compared with the classic Ilizarov method.

[Analytical method and comparison for static and dynamic headspace gas chromatography of anisole in water].

OBJECTIVE: To establish and compare the method of static headspace gas chromatography hydrogen flame detector (static headspace method) and purge and trap gas chromatography-mass spectrometry (dynamic headspace method) of anisole in water. METHODS: Nitrogen gas was used as carrier gas in the static headspace method, 5 g NaCl as matrix modifier was added into 10 ml water. The sample was balanced with high speed vibration at 75°C for 30 min, and anisole was detected by gas chromatography and quantified with external standard. Helium was used as carrier gas in dynamic headspace method, 5.0 ml water and 0.004 mg/L internal standard fluorobenzene was purged into the purge and trap apparatus. After purging, trapping and desorption, anisole was detected by the gas chromatography-mass spectrograph, confirmed by the retention time and comparison of mass-spectrogram in spectrum library and quantified with internal standard. The repeatability and sensitivity of assay were evaluated. RESULTS: A good linear range for anisole was observed in static headspace gas chromatography and dynamic headspace gas chromatography-mass spectrometry, within the range of 10 - 500 µg/L and 0.5 - 60.0 µg/L respectively. The linear regression equation was Y = 782.150X + 1.3446 and Y = 0.0358X - 0.0209 respectively, both the correlation coefficient ≥ 0.999. The detection limit (LOD) were 0.002 µg/L and 0.110 µg/L, the lower limit of quantitation (LOQ) were 0.006 µg/L and 0.350 µg/L, the relative standard deviation (RSD) were 1.8% - 2.3% and 2.0% - 3.4%, and the spiking recovery were 93% - 101% and 96% - 101% respectively. CONCLUSION: The methods of static headspace gas chromatography and dynamic headspace gas chromatography-mass spectrometry are simple and can measure anisole in water quickly, sensitively and accurately.

[Biological changes after axonal stretch and their mechanisms].

Research on peripheral nervous injuries, especially the stretched injuries, is important to improve the clinical effectiveness and alleviate the patients's pain. In recent years, the biological changes and mechanics of stretched axons have been hot topics. This article reviews the recent advances in the morphological changes of axons as well as changes in cellular membrane, cytoskeleton, cellular metabolism, and action potential after axonal stretch.