[Recent advances in the development and application of effervescence-assisted microextraction techniques].

Effervescence-assisted microextraction (EAM) is a novel sample pretreatment method based on the reaction of CO2 and H+ donors to generate CO2 bubbles and promote rapid dispersion of the extractant. During this process, the unique dispersion method increases the contact area between the target molecule and the extraction solvent, and the adsorption/extraction efficiency of the adsorbent/extractant toward the target molecule is also enhanced. The EAM technique is of particular interest due its convenient application, low running costs, reduced solvent consumption, high extraction efficiency, and environmental friendliness. Benefiting from the rapid development of extractants, the evolution and application of the EAM technology is becoming more tuned and diversified. Indeed, the synthesis of new extractants, such as nanomaterials with multi-pore structures, large specific surface areas, and rich active sites, has attracted extensive attention, as has the development of ionic liquids with strong extraction abilities and high selectivities. As a result, the EAM technology has been widely applied to the pretreatment of target compounds in various samples, such as food, plant, biological, and environmental samples. However, since these samples often contain polysaccharides, peptides, proteins, inorganic salts, and other interfering substrates, it is necessary to remove some of these substances prior to extraction by EAM. This is commonly achieved using methods such as vortexing, centrifugation, and dilution, among others. The treated samples can then be extracted using the EAM method prior to detection using high performance liquid chromatography (HPLC), gas chromatography (GC), and atomic absorption spectroscopy (AAS) to detect substances such as heavy metal ions, pesticide residues, endocrine-disrupting compounds (EDCs), and antibiotics. Using effervescence as a novel assisted method for the dispersion of solvents or adsorbents, the concentrations of Pb2+, Cd2+, Ni2+, Cu2+, bisphenol, estrogen, and the pyrethyl pesticides have previously been successfully determined. Moreover, many influencing factors have been evaluated during method development, including the composition of the effervescent tablet, the solution pH, the extraction temperature, the type and mass/volume of extractant, the type of eluent, the eluent concentration, the elution time, and the regeneration performance. Generally, the cumbersome single factor optimization and multi-factor optimization methods are also required to determine the optimal experimental conditions. Following determination of the optimal experimental conditions, the EAM method was validated by a series of experimental parameters including the linear range, the correlation coefficient (R2), the enrichment factor (EF), the limit of detection (LOD), and the limit of quantification (LOQ). In addition, the use of this method has been demonstrated in actual sample testing, and the obtained results have compared with those achieved using similar detection systems and methods to ultimately determine the accuracy, feasibility, and superiority of the developed method. In this paper, the construction of an EAM method based on nanomaterials, ionic liquids, and other emerging extractants is reviewed, wherein the preparation method, application range, and comparison of similar extractants were evaluated for the same extraction system. In addition, the current state-of-the-art in relation to EAM research and application when combined with HPLC, cold flame AAS, and other analytical techniques is summarized in terms of the detection of harmful substances in complex matrices. More specifically, the samples evaluated herein include dairy products, honey, beverages, surface water, vegetables, blood, urine, liver, and complex botanicals. Furthermore, issues related to the application of this technology are analyzed, and its future development trend in the field of microextraction is forecasted. Finally, the application prospects of EAM in the analysis of various pollutants and components are proposed to provide reference for monitoring pollutants in food, environmental, and biological samples.

Ultrafine V2O5-anchored 3D N-doped carbon nanocomposite with augmented dual-enzyme mimetic activity for evaluating total antioxidant capacity.

Total antioxidant capacity (TAC) can be evaluated by detecting the content of antioxidants, such as ascorbic acid, based on the enzyme-mimetic activity of nanomaterials. Herein, we fabricated a 3D-V2O5/NC nanocomposite using a self-templating strategy, which achieved ultrafine particles (∼2.5 nm), a porous carbon layer, large specific surface area (152.4 m2/g), N-doping and heterogeneous structure. The strong catalytic activity of 3D-V2O5/NC resulted from the integrated effect between the ultrafine structure of V2O5 nanoparticles and the 3D porous nitrogen-doped carbon framework, effectively increasing the number of active sites. This nanozyme presented a higher catalytic activity than its components or precursors in the nanocomposite (e.g., VN/NC, NC, V2O5, and VO2/g-C3N4). ROS scavenging experiments confirmed that the dual enzyme-like activity of 3D-V2O5/NC (catalase-like and oxidase-like) resulted from their co-participation of ‧O2-, h+ and ‧OH, among which ‧O2- played a crucial role in the catalytic color reaction. By virtue of the 3D-V2O5/NC nanoenzyme activity and TMB as a chromogenic substrate, the mixed system of 3D-V2O5/NC + TMB + H2O2 provided a low detection limit (0.03 µM) and suitable recovery (93.0-109.5%) for AA. Additionally, a smartphone-based colorimetric application was developed employing "Thing Identify" software to evaluate TAC in beverages. The colorimetric sensor and smartphone-detection platform provide a better or comparable analytical performance for TAC assessment in comparison to commercial ABTS test kits. The newly developed smartphone-based colorimetric platform presents several prominent advantageous, such as low cost, simple/rapid operation, and feasibility for outdoor use.

Prevalent Introgression Underlies Convergent Evolution in the Diversification of Pungitius Sticklebacks.

New mutations and standing genetic variations contribute significantly to repeated phenotypic evolution in sticklebacks. However, less is known about the role of introgression in this process. We analyzed taxonomically and geographically comprehensive genomic data from Pungitius sticklebacks to decipher the extent of introgression and its consequences for the diversification of this genus. Our results demonstrate that introgression is more prevalent than suggested by earlier studies. Although gene flow was generally bidirectional, it was often asymmetric and left unequal genomic signatures in hybridizing species, which might, at least partly, be due to biased hybridization and/or population size differences. In several cases, introgression of variants from one species to another was accompanied by transitions of pelvic and/or lateral plate structures-important diagnostic traits in Pungitius systematics-and frequently left signatures of adaptation in the core gene regulatory networks of armor trait development. This finding suggests that introgression has been an important source of genetic variation and enabled phenotypic convergence among Pungitius sticklebacks. The results highlight the importance of introgression of genetic variation as a source of adaptive variation underlying key ecological and taxonomic traits. Taken together, our study indicates that introgression-driven convergence likely explains the long-standing challenges in resolving the taxonomy and systematics of this small but phenotypically highly diverse group of fish.

[Adsorption characteristics of six bisphenol compounds on magnetic three-dimensional nitrogen-doped carbon nanomaterials and their use in effervescent reaction-assisted dispersive microextraction].

Herein, we successfully prepared magnetic Co/Ni-based N-doped 3D carbon nanotubes and graphene nanocomposites (CoNi@NGC) using a simple high-temperature calcination method. The CoNi@NGC nanocomposites were used as adsorbents to study their adsorption performances and underlying kinetic mechanisms for six types of bisphenol compounds (BPs) in water. They were also used as extractants, and acid-base effervescent tablets were used to enhance extractant dispersion with the aid of vigorous CO2 bubbling. Thus, a novel pretreatment method was developed, denoted effervescent reaction-assisted dispersive solid-phase microextraction (ER-DSM), which was combined with high performance liquid chromatography-fluorescence detection (HPLC-FLD) to rapidly quantify trace-level BPs in several drinks. The morphology and structure of the CoNi@NGC adsorbent were characterized in detail using scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FT-IR), N2 adsorption and desorption (BET-BJH), X-ray photoelectron spectroscopy (XPS), and vibrating sample magnetometry (VSM). The CoNi@NGC nanocomposites were successfully doped with N and exhibited large specific surface areas (109.42 m2/g), abundant pores, and strong magnetic properties (17.98 emu/g).Key parameters were rigorously optimized to maximize the adsorption performance of CoNi@NGC, including adsorbent dosage, solution pH, temperature, and time. Under the constant conditions of pH=7, 5 mg of CoNi@NGC, initial BP concentrations of 5 mg/L, and 5 min of shaking at 298 K, the adsorption percentages of bisphenol M (BPM) and bisphenol A (BPA) reached respective maxima of 99.01% and 98.21%. Remarkably, those of bisphenol Z (BPZ), BPA, and BPM reached almost 100% after 90 min. The adsorption between the BPs and CoNi@NGC was mainly governed by hydrogen bonds, electrostatic interactions, and π-π conjugation. The entire adsorption process was consistent with Freundlich adsorption and a quasi-second-order kinetic equation, representing spontaneous adsorption. Via integration with HPLC-FLD, ER-DSM was used to rapidly extract and analyze trace-level BPs in six types of boxed drinks. Critical factors were optimized individually, including the type of eluent and elution time and volume, which influenced the enrichment effect. Under the optimized extraction conditions (pH=7, 5 mg CoNi@NGC, elution with 2 mL acetone for 6 min), the limits of detection and quantification of the novel extraction method were 0.06-0.20 and 0.20-0.66 µg/L, respectively. The intra- and inter-day precisions spanned the ranges 1.44%-4.76% and 1.69%-5.36%, respectively, and the recoveries in the actual samples were in the range 82.4%-103.7%. Moreover, the respective residual levels of BPA and BPB in peach juice samples were 2.09 and 1.37 µg/L. Regeneration studies revealed that the CoNi@NGC adsorbent could be reused at least five times, which significantly reduced the cost of evaluation. In summary, compared to other methods, this method displays the advantages of a high sensitivity, rapid extraction, and environmental friendliness, thereby exhibiting considerable potential for use in conventional monitoring of trace-level BPs in food matrices.

Colorimetric assay based on NiCo2S4@N,S-rGO nanozyme for sensitive detection of H2O2 and glucose in serum and urine samples.

Traditional bimetallic sulfide-based nanomaterials often have a small specific surface area (SSA), low dispersion, and poor conductivity, thereby limiting their wide applications in the nanozyme-catalytic field. To address the above issues, we herein integrated NiCo2S4 with N,S-rGO to fabricate a nanocomposite (NiCo2S4@N,S-rGO), which showed a stronger peroxidase-mimetic activity than its pristine components. The SSA (155.8 m2 g-1) of NiCo2S4@N,S-rGO increased by ∼2-fold compared to NiCo2S4 with a pore size of 7-9 nm, thus providing more active sites and charge transfer channels. Based on the Michaelis-Menten equation, the affinity of this nanocomposite increased 40% and 1.1∼10.6-fold compared with NiCo2S4 with N,S-rGO, respectively, highlighting the significant enhancement of the peroxidase-like activity. The enhanced activity of this nanocomposite is derived from the joint participation of ˙OH, ˙O2 -, and photogenerated holes (h+), and was dominated by h+. To sum up, N,S-codoping, rich S-vacancies, and multi-valence states for this nanocomposite facilitate electron transfer and accelerate reaction processes. The nanocomposite-based colorimetric sensor gave low detection limits for H2O2 (12 µM) and glucose (0.3 µM). In comparison with the results detected by a common glucose meter, this sensor provided the relative recoveries across the range of 97.4-101.8%, demonstrating its high accuracy. Moreover, it exhibited excellent selectivity for glucose assay with little interference from common co-existing macromolecules/ions, as well as high reusability (>6 times). Collectively, the newly developed colorimetric sensor yields a promising methodology for practical applications in H2O2 and glucose detection with advantages of highly visual resolution, simple operation, convenient use, and satisfactory sensitivity.

N, S-co-doped carbon/Co1-xS nanocomposite with dual-enzyme activities for a smartphone-based colorimetric assay of total cholesterol in human serum.

We fabricated a novel N,S-co-doped carbon/Co1-xS nanocomposite (NSC/Co1-xS) using a facile sol-gel approach, which featured a multiporous structure, abundant S vacancies and Co-S nanoparticles filling the carbon-layer pores. When the Co1-xS nanoparticles were anchored onto the surface of N,S-co-doped carbon, a synergistic catalysis action occurred. The NSC/Co1-xS nanocomposites possessed both peroxidase-like and oxidase-mimetic dual-enzyme activities, in which the oxidase-mimetic activity dominated. By scavenger capture tests, the nanozyme was demonstrated to catalyze H2O2 to produce h+, •OH and •O2-, among which the strongest and weakest signals were h+ and •OH, respectively. The multi-valence states of Co atoms in the NSC/Co1-xS structure facilitated electronic transfer that enhanced redox reactions, thereby improving the resultant color reaction. Based on the NSC/Co1-xS's enzyme-mimetic catalytic reaction, a visual colorimetric assay and Android "Thing Identify" application (app), installed on a smartphone, offered detection limits of 1.93 and 2.51 mg/dl, respectively, in human serum samples. The selectivity/interference experiments, using fortified macromolecules and metal ions, demonstrated that this sensor had high selectivity and low interference potential for cholesterol analysis. Compared to standard assay kits and previously reported visual detection, the Android smartphone-based assays provided higher accuracy (recoveries up to 93.6-104.1%), feasibility for trace-level detection, and more convenient on-site application for cholesterol assay due to the superior enzymatic activity of NSC/Co1-xS. These compelling performance metrics lead us to posit that the NSC/Co1-xS-based nanozymic sensor offers a promising methodology for several practical applications, such as point-of-care diagnosis and workplace health evaluations.

Study on the effect of CYP2C19 genetic polymorphism and plasma concentration on clopidogrel resistance.

At present, the mechanism for clopidogrel resistance (CR) is incompletely understood. Here, we aimed to analyze of the association of plasma concentration of clopidogrel active metabolites (CAM) and CYP2C19 genetic polymorphism with CR. We assigned 77 patients to receive CLP at a loading dose of 300mg on day 1, followed by 75mg per day from day 2 to day 6. Three peripheral venous blood samples were collected for analysis. Our results showed that plasma concentration of CAM in extensive metabolizers (EMs) group (2.48(1.31, 5.67) ng/mL) was higher than that in intermediate metabolizers (IMs) group (1.44(1.18,3.55) ng/mL) and that in poor metabolizers (PMs) (1.18(1.12,1.33) ng/mL) group was the lowest (H=14.58, P=0.001). Besides, the incidence of CR in EMs group(11.1%) was lower than that in IMs group (20.0%) and that in IMs group was lower than that in PMs group (45.5%) (χ2=6.344, P=0.042). In addition, our findings confirmed that the incidence of chest tightness in IMs group (40.0%) and PMs group (50.0%) was higher than that in EMs group (9.1%) (P=0.015). Over the follow-up period, it was found that CYP2C19 and plasma concentration of CAM were related to the incidence of chest tightness. Our findings indicated that in addition to CYP2C19, plasma concentration of CAM may be an important factor in predicting CR.

Effect of simulated geomagnetic activity on myocardial ischemia/reperfusion injury in rats

Abstract Objective: To study the response of myocardial ischemia/reperfusion injury (MI/RI) in rats to simulated geomagnetic activity. Methods: In a simulated strong geomagnetic outbreak, the MI/RI rat models were radiated, and their area of myocardial infarction, hemodynamic parameters, creatine kinase (CK), lactate dehydrogenase (LDH), melatonin, and troponin I values were measured after a 24-hour intervention. Results: Our analysis indicates that the concentrations of troponin I in the geomagnetic shielding+operation group were lower than in the radiation+operation group (P<0.05), the concentrations of melatonin in the shielding+operation group and normal+operation group were higher than in the radiation + operation group (P<0.01), and the concentrations of CK in the shielding + operation group were lower than in the radiation + operation group and normal + operation group (P<0.05). Left ventricular developed pressure (LVDP) and ± dP/dtmax in the radiation+operation group were lower than in the shielding + operation group and normal+operation group (P<0.01). Left ventricular end-diastolic pressure (LEVDP) in the shielding + operation group was higher than in the normal + operation group (P<0.05). There was no significant difference in area of myocardial infarction and LDH between the shielding + operation group and the radiation + operation group. Conclusion: Our data suggest that geomagnetic activity is important in regulating myocardial reperfusion injury. The geomagnetic shielding has a protective effect on myocardial injury, and the geomagnetic radiation is a risk factor for aggravating the cardiovascular and cerebrovascular diseases.

Effect of Simulated Geomagnetic Activity on Myocardial Ischemia/Reperfusion Injury in Rats.

OBJECTIVE: To study the response of myocardial ischemia/reperfusion injury (MI/RI) in rats to simulated geomagnetic activity. METHODS: In a simulated strong geomagnetic outbreak, the MI/RI rat models were radiated, and their area of myocardial infarction, hemodynamic parameters, creatine kinase (CK), lactate dehydrogenase (LDH), melatonin, and troponin I values were measured after a 24-hour intervention. RESULTS: Our analysis indicates that the concentrations of troponin I in the geomagnetic shielding+operation group were lower than in the radiation+operation group (P<0.05), the concentrations of melatonin in the shielding+operation group and normal+operation group were higher than in the radiation + operation group (P<0.01), and the concentrations of CK in the shielding + operation group were lower than in the radiation + operation group and normal + operation group (P<0.05). Left ventricular developed pressure (LVDP) and ± dP/dtmax in the radiation+operation group were lower than in the shielding + operation group and normal+operation group (P<0.01). Left ventricular end-diastolic pressure (LEVDP) in the shielding + operation group was higher than in the normal + operation group (P<0.05). There was no significant difference in area of myocardial infarction and LDH between the shielding + operation group and the radiation + operation group. CONCLUSION: Our data suggest that geomagnetic activity is important in regulating myocardial reperfusion injury. The geomagnetic shielding has a protective effect on myocardial injury, and the geomagnetic radiation is a risk factor for aggravating the cardiovascular and cerebrovascular diseases.

WWOX CNV-67048 Functions as a Risk Factor for Epithelial Ovarian Cancer in Chinese Women by Negatively Interacting with Oral Contraceptive Use.

Copy number variations (CNVs) have attracted increasing evidences to represent their roles as cancer susceptibility regulators. However, little is known about the role of CNV in epithelia ovarian cancer (EOC). Recently, the CNV-67048 of WW domain-containing oxidoreductase (WWOX) was reported to alter cancer risks. Considering that WWOX also plays a role in EOC, we hypothesized that the CNV-67048 was associated with EOC risk. In a case-control study of 549 EOC patients and 571 age (±5 years) matched cancer-free controls, we found that the low copy number of CNV-67048 (1-copy and 0-copy) conferred a significantly increased risk of EOC (OR = 1.346, 95% CI = 1.037-1.747) and it determined the risk by means of copy number-dependent dosage effect (P = 0.009). Data from TCGA also confirmed the abovementioned association as the frequency of low copies in EOC group was 3.68 times more than that in healthy group (P = 0.023). The CNV also negatively interacted with oral contraceptive use on EOC risk (P = 0.042). Functional analyses further showed a lower mRNA level of WWOX in tissues with the 0-copy or 1-copy than that in those with the 2-copy (P = 0.045). Our data suggested the CNV-67048 to be a risk factor of EOC in Chinese women.

[The cytokine homeostasis was regulated by over-expression of Sirt1 in collagen-induced arthritis mice].

OBJECTIVE: To investigate the effects of over-expression of Sirt1 on cytokines in the collagen type 2-induced arthritis (CIA) mice. METHODS: The female DBA/1 mouse CIA model was established by subcutaneous injection of collagen type 2. Recombinant adenovirus carrying Sirt1 gene was infected into CIA mice through tail vein injection. The effects of over-expression of Sirt1 on CIA mice were assessed by measuring arthritis index. The serum levels of cytokines including interleukin 1ß (IL-1ß), tumor necrosis factor α (TNF-α), IL-17, IL-4 and IL-10 in CIA mice were examined by ELISA. The mRNA levels of Sirt1, matrix metalloproteinase-13 (MMP-13) and tissue inhibitor of metalloproteinase-1 (TIMP-1) were detected by real-time quantitative PCR (qRT-PCR). The protein levels of NF-κB subunit p65 and acetylated p65 were determined by Western blotting. RESULTS: Compared with control groups, over-expression of Sirt1 significantly ameliorated the symptoms of arthritis in CIA mouse. Furthermore, proinflammatory factors (IL-1ß, TNF-α, IL-17) decreased while anti-inflammatory factors (IL-4 and IL-10) increased in CIA mice. The over-expression of Sirt1 significantly down-regulated MMP-13 mRNA level and up-regulated TIMP-1 mRNA level. Additionally, the over-expressed Sirt1 reduced acetylation of p65. CONCLUSION: Over-expression of Sirt1 may regulate the balance of cytokines in CIA mice.

[Application of the vanillin sulfuric acid colorimetry-ultraviolet spectrometry on quality evaluation of Panax notoginseng].

In this study, Panax notoginseng samples were extracted by chloroform, ethanol and water, or by those extracted solution with 5% vanillin sulfuric acid to establish two kinds of UV fingerprint of P. notoginseng which were compared by applying the common and variation peak ratio dual index sequence analysis method and SIMCA software qualitative analysis. The results indicated that the optimization extraction time of P. notoginseng samples was 20 min with chloroform, ethanol and water extraction, but the fingerprint differed significantly after add vanillin sulfuric acid. The common peak ratios of UV fingerprint of P. notoginseng were scattered. The minimum was 25% (Y5-Y8), while the maximum was 84.38% (Y11-Y13, Y20-Y21). The maximum variation peak ratio was 177.78% (Y8-Y5), meanwhile, the variation peak ratios of several samples were more than 100%. However, the common peak ratios of UV fingerprint of P. notoginseng with vanillin sulfuric acid were concentrated (distributed in the range of 50%-70%): the minimum was 42.86%(Y1-Y19), whereas the maximum was 79.55% (Y22-Y23); the range of the variation peak ratios was also smaller with the ranges of 20%-50% in general. The result of the dual index sequence analysis was agreement with the fingerprint implied. The similarity of the UV fingerprint of the extracts of P. notoginseng after adding vanillin sulfuric acid was greater than before. Both the ages and origin was related with the difference of UV fingerprint. The similarity of the two samples with same age was more significant than those with different ages. The similarity and difference between samples was no correlation with the distance of geographic space, the near origin samples maybe have a significant similarity or difference. This method appears as good alternative for evaluate quality of the P. notoginseng and can distinguish at least two samples quantitatively, duo to it reaches the limitation of the multiple methods which only could be used to indistinctly distinguish herbs.

[Clinical evaluation of the antioxidant activity of astragalus in women with gestational diabetes].

OBJECTIVE: To evaluate the antioxidant activity of astragalus and its therapeutic effect on gestational diabetes. METHODS: Eighty-four pregnant women with gestational diabetes were divided into insulin and insulin plus astragalus groups after regular dietary control and insulin treatment to maintain stable blood glucose level. The 43 patients in insulin group received insulin injection, whereas the 41 patients in the other group received treatment with both insulin and astragalus. The SOD activity, MDA level, blood lipids and renal function were determined in both groups after the treatments. RESULTS: The patients with both insulin and astragalus treatments showed significantly increased serum SOD activity and decreased MDA level, renal function and blood lipids in comparison with those with exclusive insulin treatment. CONCLUSION: Astragalus can effectively control blood glucose, reduce the free radicals, and promote the antioxidative activity, and may play a role in the prevention and treatment of gestational diabetes.

Effect of polylactic acid glue in preventing epidural scar adhesion after laminectomy in rabbits.

OBJECTIVE: To determine the efficacy of polylactic acid glue in preventing epidural scar adhesion after laminectomy in rabbits. METHODS: Twenty-four Japanese white rabbits underwent laminectomy (including the attached ligaments) at L(2 ) and L(5). After laminectomy at L(5), polylactic acid glue was sprayed on the dura and nerve roots and this segment was taken as the experimental group. After laminectomy at L(2), nothing was used and this segment was enrolled as the self control group. Four rabbits were killed every two weeks postoperatively till the end of the experiment at 12 weeks. Then the operated spine was observed grossly, histologically and ultrastructurally to check the degree of scar formation, the status of epidural scar adhesion, the absorption of the glue, and the intracellular structure of fibroblasts. RESULTS: The glue coagulated immediately after spraying and showed excellent hemostatic effect. The glue membrane was easy to be taken away from the dura mater of the samples for 2 weeks and there were no cells in the epidural space in the experimental group. But the dura mater was covered by hematoma in the control group, which formed mild adhesion, with fibroblasts proliferating actively. In the 4th week, some glue shivers remained in the epidural space with fibroblasts increasing a little, and the dura mater was smooth in the experimental group. However, in the control group, the formed scar was fragile and conglutinated with the dura mater diffusely and fibroblasts were much more than those in the experimental group. In the 6th-12th weeks, there was a potential interspace between the scar and the dura mater, and the polylactic acid glue was absorbed completely in the experimental group. Much tough scar was found in the control group, which was very difficult to dissect from the dura mater and the surrounding tissues. From the ultrastructural observation of the fibroblasts, the nucleus became much bigger and the rough endoplasmic reticulum was much more plentiful in the control group than that in the experimental group. CONCLUSIONS: Polylactic acid glue can effectively reduce epidural cicatrization and adhesion.

[Culture of chondrocytes onto poly-DL-lactide scaffoldings: experimental study].

This experimental study was intended to find the possibility of using PDLLA as scaffolds in tissue engineering and to assess the effect of PDLLA scaffolds with different porosity on chondrocytes. Chondrocytes were cultured when they were seeded onto PDLLA scaffolds with different porosity. Under scanning electron microscope, the scaffolds in hydrophila and adsorptivity to chondrocytes and the function of the cells were observed. The chondrocytes were noted to proliferate on PDLLA scaffolds with different porosity, those with 90%-96% porosity being significantly better. So PDLLA can be used as a scaffold in tissue engineering, and the proper porosity of PDLLA scaffolds should be 90% approximately 96%.

[Experimental study on the polylactic acid glue in preventing epidural adhesion].

OBJECTIVE: To determine the ability of the polylactic acid glue (PLA-G) in preventing epidural adhesion after laminectomy. METHODS: Each of the 24 randomly selected rats was done laminectomy of L2 and L5. The PLA-G, which would change from liquid to solid when meets with serum, was used in the epidural site of L5 to become a half-solid membrane (the experimental group, EG). The PLA-G was not used in the same site of L2 (the control group, CG). The gross anatomical, histological, and microscopical evaluation were made 2, 4, 6, 8, 10 and 12 weeks after operation; electron microscope observation was also made on two rats 4 weeks after operation(both EG and CG). RESULTS: Obvious epidural space was observed between dura mater and scar tissue (ST), but no cells in the epidural space were observed in EG 2 weeks after operation. Corps of the red cells between dura mater and ST and proliferation of fibroblast cell (FB) were observed in CG 2 weeks after operation. Some remaining glue shivered in the epidural space with lightly increasing fibroblast and smooth dura mater were observed in EG 4 weeks after operation. However, fragile scar adhered with dura mater diffusely and more FB were observed in CG. From the 6th week to the 12th week, a potential interspace between scar and dura mater was observed and PLA glue was absorbed completely in EG. However, tougher scar, which was very difficult to dissect from dura mater and surrounding tissues, was observed. According to the fibroblast ultrastructure observation, bigger nucleus and more plentiful rough endoplasmic reticulum were observed in CG. CONCLUSION: The PLA-G can effectively reduce the epidural scar and adhesion in animal experiment.

[Effect of absorbable poly-DL-lactide rods on experimental fracture healing].

This study was designed to assess the effect of a home-bred poly-DL-lactide (PDLLA) rods on experimental fracture healing. An operation was performed to create bilateral ulnar and radial fractures of forearm in 15 rabbits. The right sides were fixed with 2 PDLLA (Mv = 34 x 10(4), 1.6 mm x 1.6 mm x 30 mm) rods, and the contralateral sides were fixed with 2 Kirschner wires to be used as controls. After operation, casts were used for external fixation, and the joint above and the joint below the fracture were immobilized. The casts were removed at the 6th week after operation. The specimens were removed at specific intervals between 2 and 12 weeks. Histologically, the light microscopy and scanning electron microscopy evaluation of the rabbit ulnar and radial fractures fixation revealed that, the fractured bone gradually healed and the PDLLA rods properly fixed on the fracture area during the implanted period. However, results suggest that internal fixation by absorbable material made the course of fracture healing slower than that in the control group, but the osteogenesis appeared to be normal. In the absorbable group, the collagenous fiber was characterized by order and orientation, and calcified normally. In conclusion, this kind of PDLLA rods have an effect on delaying the process of the normal union of fracture and should be applicable to fractures where the tissues are rich in blood supply.

[Function of fibula in stability of ankle joint].

OBJECTIVE: To summarize the function of fibula in stability of ankle joints. METHODS: Recent original articles were extensively reviewed, which were related to the physiological function and biomechanical properties of fibula, the influence of fibular fracture on stability of ankle joints and mechanism of osteoarthritis of ankle joints. RESULTS: The fibula had the function of weight-bearing; and it was generally agreed that discontinued fibula could lead to intra-articular disorder of ankle joint in children; but there were various viewpoints regarding the influence of fibular fracture on the ankle joint in adults. CONCLUSION: Fibula may play an important role in stability of ankle joint.