Molecular simulation of the rheological properties and shear thinning principles of supramolecular drilling fluids at different burial depths.

In order to investigate the rheological properties and shear thinning principles of supramolecular drilling fluids, the salt-responsive supramolecular ionomer polymers with different components were designed and the change in shear viscosity of supramolecular polymer drilling fluid system with shear rate was studied using the molecular dynamics simulation method. The result indicated that the ionic supramolecular polymer drilling fluid system exhibits better self-assembly performance than the nonionic acrylamide drilling fluid system. Moreover, the drilling fluid system exhibits the best rheological properties and self-assembly performance when the feeding ratios of the three monomers in the two polymers are m : n : o = 5 : 90 : 5 and m : n : o = 30 : 40 : 30, respectively. The shear viscosity recovery rate of the #3 ionic supramolecular polymer drilling fluid system at different burial depths (1-5 km) is >87%, where the shear viscosity is mainly determined at ambient pressure. The shear thinning phenomenon of the supramolecular polymer drilling fluid system occurs because of the combined effect of the polymer molecular orientation and entanglement structure. When the shear rate is above a critical value, the polymer molecules are oriented along the flow field direction, decreasing the shear viscosity. However, when the shear rate is very high, the entanglement structure of the molecules is opened and the mesh structure of the fluids is disrupted, decreasing the shear viscosity of the drilling fluid.

Influencing Factors of Patients' Trust in Nurses During the COVID-19 Pandemic: A Mixed-Methods Study.

OBJECTIVE: This study aimed to investigate the nurse-patient trust among in-patients in the context of the coronavirus disease (COVID-19) epidemic; it further analyzed the related influencing factors, which will provide a theoretical basis for developing corresponding measures. METHODS: This study employed a mixed-method design and analyzed 149 patients at the Hongqi Hospital, affiliated with Mudanjiang Medical University, from December 2020 to February 2021. Quantitative analysis was carried out using the "Nurse Patient Trust Scale," and qualitative analysis was performed using a semi-structured interview with in-patients. RESULTS: The average score on the scale was 46.65 ± 2.83, and the scores of the 2 dimensions were: 23.24 ± 1.51 for ability and peace of mind, and 23.32 ± 1.53 for attitude and care. According to the interview data, the factors included 3 aspects: a comfortable hospital environment and humane management measures; the nurse's own competence; and effective communication with patients. CONCLUSION: During the COVID-19 epidemic, there are still many factors affecting patients' trust in nurses that can be addressed by taking different measures. All these factors must be considered by the relevant managers and clinical nursing staff to maintain a better nurse-patient trust relationship.

A functional SNP rs895819 on pre-miR-27a is associated with bipolar disorder by targeting NCAM1.

The aberrant expression or genomic mutations of microRNA are associated with several human diseases. This study analyzes the relationship between genetic variations of miRNA and schizophrenia or bipolar disorder. We performed case-control studies for ten SNPs in a total sample of 1584 subjects. All these ten SNPs were on or near mature microRNAs. We identified the association between bipolar disorder and the T/C polymorphism at rs895819. To illustrate the function of miR-27a, we constructed several miR-27a knockout (KO) cell lines, determined candidates of miR-27a, and then verified NCAM1 as a target gene of miR-27a. Further studies revealed that the T/C polymorphism on miR-27a led to the differential expression of mature and precursor miR-27a without affecting the expression of primary miR-27a. Furthermore, the C mutation on pre-miR-27a suppresses cell migration and dopamine expression levels. Our study highlights the importance of miR-27a and its polymorphism at rs895819 in bipolar disorder.

Hyperthermic Intraperitoneal Chemotherapy plus Intravenous Chemotherapy of Paclitaxel with or without Sintilimab in Gastric Cancer: A Comparative Study.

OBJECTIVE: To compare the clinical efficacy of hyperthermic intraperitoneal chemotherapy (HIPEC) plus intravenous chemotherapy of paclitaxel with or without sintilimab in peritoneal metastasis of gastric cancer. METHODS: A total of 120 patients assessed for eligibility with peritoneal metastasis of gastric cancer treated in the oncology department of our hospital from January 2019 to June 2020 were recruited. They were concurrently randomly assigned in a 1 : 1 ratio to receive HIPEC plus sintilimab-paclitaxel intravenous chemotherapy (study group) or plus paclitaxel intravenous chemotherapy only (control group). RESULTS: The objective remission rate (ORR) of ascites in the study group was significantly higher than that in the control group. Subgroup analysis showed that an age ≤60 years or well-differentiated tumors were associated with better objective remission. After treatment, significantly higher Karnofsky Performance Status (KPS) scores were observed in the study group versus those of the control group. Adverse events reported were comparable between groups. The study group obtained longer 12-month progression-free survival (PFS) and overall survival (OS) than those of the control group. CONCLUSION: On top of HIPEC, intravenous chemotherapy with sintilimab and paclitaxel constitute an effective alternative for patients with peritoneal metastasis of gastric cancer to enhance ascites remission, ameliorate the quality of life, and prolong survival, versus with paclitaxel alone.

Role of haematopoietic cell-specific protein 1-associated protein X-1 gene in lipopolysaccharide-induced apoptosis of human dermal fibroblasts.

Wound healing may be disrupted by lipopolysaccharide (LPS)-induced mitochondrial dysfunction, inflammation, and excessive oxidative stress, which can lead to undesirable consequences. The haematopoietic cell-specific protein 1-associated protein X-1 (HAX-1) is a mitochondrial matrix protein that regulates mitochondrial function. This study aimed to comprehensively identify the role of HAX-1 in the inhibition of LPS-induced mitochondrial dysfunction and apoptosis in human dermal fibroblasts (HDFs). HAX-1 expression was assessed in the HDF-a cell line using real-time polymerase chain reaction, western blotting, and immunohistochemical staining. The viability, migration, and apoptosis of HDF-a cells were evaluated using the water-soluble tetrazolium-1 assay, transwell assay, and flow cytometry analysis, respectively. Mitochondrial function was evaluated based on reactive oxygen species (ROS) generation and mitochondrial membrane potential (ΔΨm). Our results demonstrated that LPS stimulation markedly repressed HAX-1 expression in HDFs and silencing of HAX-1 led to mitochondrial ROS accumulation, ΔΨm disruption, and abnormal mitochondrial morphology. Accordingly, overexpression of HAX-1 or administration of metformin enhanced mitochondrial fusion and normalized mitochondrial dynamics, thereby reversing LPS-induced mitochondrial dysfunction, fibroblast apoptosis, and viability and migration inhibition in HDF-a cells. These data support a mechanism wherein HAX-1 plays a crucial role in LPS-induced fibroblast apoptosis in a mitochondria-dependent manner.

Deinococcus detaillensis sp. nov., isolated from humus soil in Antarctica.

A Gram-staining-positive, non-motile, coccus or short-rod-shaped bacterium, designated H1T, was isolated from a humus soil sample in the Detaille Island of Antarctica. The 16S rRNA gene sequence result indicated that strain H1T shared the highest 16S rRNA gene sequence identity with the type strain of Deinococcus alpinitundrae (96.2%). Growth of strain H1T occurred at 4-25 °C, pH 6.0-8.0 and in the presence of 0-1.0% NaCl (w/v). The respiratory quinone was MK-8. The major fatty acids were C16:0, C17:0 cyclo and summed feature 3 (C16:1 ω7c/C16:1 ω6c). The polar lipids were aminoglycophospholipid, aminophospholipid, glycolipid and glycophospholipid. The cell wall peptidoglycan type was A3ß. The genomic DNA G + C content was 61.3 mol%. The average nucleotide identity (ANI) between strain H1T and the closely related Deinococcus members was below the cut-off level (95-96%) for species identification. Based on the above results, strain H1T represents a novel species of the genus Deinococcus, for which the name Deinococcus detaillensis sp. nov. is proposed. Type strain is H1T (= CGMCC 1.13938T = JCM 33291T).

MicroRNA-448 targets SATB1 to reverse the cisplatin resistance in lung cancer via mediating Wnt/ß-catenin signalling pathway.

This study aims to examine whether miR-448 reverses the cisplatin (DDP) resistance in lung cancer by modulating SATB1. QRT-PCR and immunohistochemistry were used to examine the miR-448 and SATB1 expressions in DDP-sensitive and -resistant lung cancer patients. A microarray was used to investigate the cytoplasmic/nucleic ratio (C/N ratios) of genes in A549 cells targeted by miR-448, followed by Dual-luciferase reporter gene assay. A549/DDP cells were transfected with miR-448 mimics/inhibitors with or without SATB1 siRNA followed by MTT assay, Edu staining, flow cytometry, qRT-PCR and western blotting. MiR-448 was lower but SATB1 was increased in DDP-resistant patients and A549/DDP cells. And the patients showed low miR-448 expression or SATB1 positive expression had poor prognosis. SATB1, as a target gene with higher C/N ratios (>1), was found negatively regulated by miR-448. Besides, miR-448 inhibitors increased resistance index of A549/DDP cells, promoted cell proliferation, increased cell distribution in S phrase, declined cell apoptosis and activated Wnt/ß-catenin pathway. However, SATB1 siRNA could reverse the above effect caused by miR-448 inhibitors. MiR-448 targeting SATB1 to counteract the DDP resistance of lung cancer cells via Wnt/ß-catenin pathway.

HPV Genotyping and Clinical Studies of Women in Yan'an Area / 现代检验医学杂志

Objective To contrast HPV genotyping and clinical characteristics of women in Yan'an and provide data support for cervical cancer screening and prevention.Methods The genotyping of HPV infection was carried out by the method of PCR amplification and reverse hybridization.To statistical analysis clinical infection distribution data.Results Found 16.48％ (332 of 2014) were positive for HPV DNA in these women.HPV-16,52 and 53 were in the top three HPV high-risk types.HPV-81,6 and 44 were in the top three HPV low-risk types.There were 219 cases (65.96％) with pure high-risk type infection,74 cases (22.29％) with pure low-risk type infection and 39 cases (11.75％) with mixed infection in positive specimens.The HPV infection rate had showed first increasing then decreasing with age,and there were significant differences among the each groups (x2=34.238,P＜0.01).There were also differences in HPV positive detection rates in different occupations and there were significant differences among the each groups (x2=50.35,P＜0.01).There were also differences in HPV positive detection rates in different regions,and there were significant differences among the each groups (x2 =12.084,P＜0.05).Single infection was highest in HPV infection.Conclusion HPV infection was different in different populations,regions and ages,and it is of great significance to carry out HPV screening for early prevention and treatment of cervical cancer.

Comparable Function of γ-Tocopherols in Asthma Remission by Affecting Eotaxin and IL-4.

BACKGROUND: Bronchial asthma is one of the world's most common chronic disorders dangerous to human health. It has been hypothesized that the increased number of asthma sufferers may be due to changing antioxidant intake or vitamin deficiency. However, the influence of vitamins on asthma has rarely been considered. OBJECTIVES: The aim of this study was to explore the effects of γ-tocopherols, a specific form of vitamin E, on asthma remission together with the possible mechanism behind the process. MATERIAL AND METHODS: Eosinophil counting was applied to detect the total number of cells, eosinophils and lymphocytes. Meanwhile, HE staining was used for morphological detection. In addition, the eotaxin and IL-4 levels in the serum and bronchoalveolar lavage fluid were measured using ELISA technology. RESULTS: The cell counting results showed that γ-tocopherols possesses the capability to reduce the number of eosinophils. Moreover, the exudation of inflammatory cells together with the hyperplasia of goblet cells was also found to experience significant inhibition when treated with γ-tocopherols. Furthermore, the high levels of eotaxin and IL-4 in the asthma group were evidently reduced under the treatment of γ-tocopherols which was comparable with hexadecadrol. CONCLUSIONS: γ-tocopherols can remit asthma by regulating the level of eotaxin and IL-4. Moreover, γ-tocopherols may be regarded as a potential candidate for asthma treatment after much deeper explorations.

Long-term postoperative outcomes of bilateral lateral rectus recession vs unilateral recession-resection for intermittent exotropia.

AIM: To discuss the long-term postoperative results of bilateral lateral rectus recession (BLR) and unilateral lateral rectus recession-medial rectus resection (RR) in therapy of intermittent exotropia. METHODS: We retrospectively analyzed 213 cases of intermittent exotropia who underwent surgery between 2008 and 2010. The patients were grouped into BLR group and RR group. Motor outcomes were divided into three groups on the basis of the angle of deviation after surgery: overcorrection (esotropia/phoria >5(Δ)), orthophoria (esotropia/phoria ≤5(Δ) to exotropia/phoria ≤10(Δ)), and undercorrection/recurrence (exotropia/phoria >10(Δ)). Titmus test was used to evaluate stereoacuity, the stereoacuity <800s of arc meaned the patients had stereopsis. Surgical outcome including motor criteria and sensory status were compared at postoperative 6, 12, 24mo and at 36mo examination between groups. RESULTS: At 12, 24mo after surgery, the motor outcomes had no difference (P>0.05) between groups. However, the motor outcomes at 6, 36mo were signally different in each group, indicating the success rate in RR group at 6mo was higher than that in BLR group (83.02% vs 82.24%, P<0.05) but the result was contrary at the 3y examination (60.75% vs 43.40%, P<0.05). No statistical significance were found in the sensory outcomes between the groups at mean of 3.7y follow-up. CONCLUSION: The motor outcomes in RR group were better than in BLR group at 6mo after surgery, while the 3y outcomes were better in BLR group. This may be due to the recurrence rate of the BLR was lower than the RR group's.

Antibacterial epipolythiodioxopiperazine and unprecedented sesquiterpene from Pseudallescheria boydii, a beetle (coleoptera)-associated fungus.

Pseudallescheria boydii residing in the gut of coleopteran (Holotrichia parallela) larva produces four new epipolythiodioxopiperazine (ETP) boydines A-D (3-6) and two novel sesquiterpene boydenes A (7) and B (10), in addition to bisdethiobis(methylthio)-deacetylaranotin (1), bisdethiodi(methylthio)-deacetylapoaranotin (2), AM6898 A (8) and ovalicin (9). The structure elucidation was accomplished by a combination of spectral methods with quantum chemical calculations of optical rotations and electronic circular dichroism (ECD) spectra. Boydine B (4) was shown to be active against the clinical strains Bifidobacterium sp., Veillonella parvula, Anaerostreptococcus sp., Bacteroides vulgatus and Peptostreptococcus sp. with an MIC range of 0.2-0.8 µM, and the pharmacophore 3-hydroxy-2,4,6-trimethyl-5-oxooct-6-enoyl chain of 4 was shown to have (2R,3S,4S)-configurations. Boydene A (7) possessed an unprecedented carbon skeleton, suggesting an unusual biochemistry that allows an intramolecular Aldol addition in the fungus. Collectively, the finding may inspire the discovery of new antibacterial agents and the understanding on biosyntheses of polythiodioxopiperazine and sesquiterpene metabolites.

[Preparation and release mechanism of gestodene reservoir-type intravaginal rings].

This study taking gestodene (GEST) as a model, investigated the factors affecting reservoir-type intravaginal ring (IVR)'s drug release. This paper reported a gestodene intravaginal ring of reservoir design, comprising a gestodene silicone elastomer core encased in a non-medicated silicone sheath, separately manufactured by reaction injection moulding at 80 degrees C and heating vulcanization at 130 degrees C is reported. The test investigated the factors affecting drug release through a single variable method, taking the drug release rates of 21 days as standards. When changing the thickness of the controlling sheath outside, the ratio of the first day of drug release and mean daily release (MDR), named the relatively burst effect, is closing to 1 with the thickness of controlling sheath increasing, while the 1.25 mm sheath corresponding to 1.04 controlled the burst release effectively; a positive correlation (r = 0.992 2) existed between the average drug release (Q/t) and drug loading (A) within a certain range. The C6-165 controlling sheath with high solubility of GEST is easier to achieve controlled release of the drug; GEST crystalline power is more effective to implement controlled release of drugs among difficent states of the drug. A 1/4 fractional segment core gives a relatively burst effect of 1.76, while the 1/1 and 1/2 are 1.93 and 1.87 separately, at the same drug loading, concluding that use of a fractional segment core would allow development of a suitable GEST reservoir IVR. In summary, GEST reservoir-type IVR could be adjusted by the thickness of controlling sheath, the loading of drug, the material properties of controlling sheath, the dispersion state of drug, the additive composition and structure of intravaginal ring, to control the drug release behavior and achieve the desired drug release rate.

Gene pleiotropy constrains gene expression changes in fish adapted to different thermal conditions.

Understanding the factors that shape the evolution of gene expression is a central goal in biology, but the molecular mechanisms behind this remain controversial. A related major goal is ascertaining how such factors may affect the adaptive potential of a species or population. Here we demonstrate that temperature-driven gene expression changes in fish adapted to differing thermal environments are constrained by the level of gene pleiotropy estimated by either the number of protein interactions or gene biological processes. Genes with low pleiotropy levels were the main drivers of both plastic and evolutionary global expression profile changes, while highly pleiotropic genes had limited expression response to temperature treatment. Our study provides critical insights into the molecular mechanisms by which natural populations can adapt to changing environments. In addition to having important implications for climate change adaptation, these results suggest that gene pleiotropy should be considered more carefully when interpreting expression profiling data.

Prevalence and treatment gap of active convulsive epilepsy: a large community-based survey in rural West China.

PURPOSE: Active convulsive epilepsy (ACE) impacts patients greatly, especially in low-income countries where patients do not receive appropriate treatment. In the present study, we measured the prevalence and treatment gap (TG) of ACE in rural West China. METHODS: Six rural areas in West China that have a total population of 3,541,319 were selected to conduct prevalence and TG estimates of ACE via a clue survey from 2007 to 2009. Clue survey here is a community-based screening strategy among defined population which requires employed well-trained local physicians//health workers to collect all clues available to discover/identify/recruit patients within a study period. Questionnaire-based interviews were used for the identification of ACE patients, and information was obtained during the survey. Prevalence and TG of ACE were calculated. RESULTS: A total of 6547 patients with ACE were identified. The estimated prevalence of ACE was 1.8 per 1000 in the general population, with the prevalences in males and females determined to be 2.0 and 1.7, respectively (p<0.001). The TG in the general population was 66.3%, and it was 66.6% and 66.0% in males and females, respectively (p>0.05). The TG figures dropped with advancing age and increased above 30 years of age. Patients aged 60 years or older had the largest TG (77.8%); those with disease course less than 10 years showed a larger TG and those who experienced two to five seizures annually had a significantly larger TG (70.6%). Additionally, only 63.9% of the ACE patients included in the study were aware of the disease and had consulted a doctor. CONCLUSIONS: There exists a large TG of ACE in West China rural areas. Majority of those ever consulted a doctor but failed to receive or adhere to an appropriate treatment program. Management including public education as well as training of local physicians were necessary to fill that gap.

[Denitrification study of Elodea nuttallii-nitrogen cycling bacteria restoration in Meiliang Bay, Taihu Lake].

Undisturbed sediment cores were collected from Meiliang Bay, Taihu Lake, and the integrated Elodea nuttallii-nitrogen cycling bacteria technology was applied as a restoration method. The effects of the Elodea nuttallii-nitrogen cycling bacteria technology on sediment denitrification was observed by isotope pairing technique. The highest denitrification rate of 104.64 micromol x (m2 x h)(-1) was achieved in sediments with Elodea nuttallii-nitrogen cycling bacteria assemblage. The abundance of nirS, nirK and nosZ genes involved in denitrification processes in the sediments (within 2 cm below the water-sediment interface) were measured by real-time quantitative PCR (RT-qPCR). The abundance of nirS and nosZ genes in the sediments with restoration treatments was increased, which was more than one order of magnitudes higher than that in bare sediments. The results indicated that the presence of macrophyte and nitrogen cycling bacteria could increase benthic nitrogen removal by facilitating coupled nitrification-denitrification and uncoupled nitrification-denitrification.

Enhancing medical compliance of patients with convulsive epilepsy in rural community: a randomized intervention trial.

PURPOSE: This randomized intervention trial was to determine whether the implementation of a practical intervention was effective in enhancing medical compliance and improving seizure control among patients with convulsive epilepsy in rural communities in western China. METHODS: Two of four areas were randomly selected for this study and assigned to be the intervention group (IG) and the control group (CG), respectively. An intervention package with four components (intensive education, consultation services, maintenance of an epilepsy tracking card, and repeated reminders) was formulated. Medical compliance included antiepileptic drug (AED) adherence and lifestyle; each was graded on a 6-point scale with possible scores. Medical compliance and seizure control were measured and compared between the groups before and after the intervention. In addition, correlation of both changes in medical compliance and seizure frequency were investigated. KEY FINDINGS: After 1-year follow-up, 183 patients in the IG (105 male) and 177 in the CG (99 male) remained for the analysis. At the end of the study, the average number of seizures in the IG declined 18.3% compared to that prior to the intervention (after 6-month phenobarbital monotherapy), nearly twice as much as in CG (9.1%) with statistical difference (p = 0.023). The proportion of patients with a reduction in seizures >50% (including those who were seizure-free) rose to 79.8% in the IG compared to 61.0% in the CG (p < 0.05). With regard to medical compliance, the majority of the IG members were rated as excellent or very good, but medical compliance remained nearly unchanged for the CG. A moderate correlation was found between the changes in AED adherence and seizure control (r = 0.4, p < 0.05), and a weaker correlation was found between lifestyle and seizure control (r = 0.328, p < 0.05). SIGNIFICANCE: This intervention package proved to be efficient in enhancing medical compliance and improving seizure control in rural communities of resource-poor areas.

[Preparation of a novel modified hydrogel and study of its adsorption performance].

A novel copolymer hydrogel poly(Hydroxyethyl methacrylate/N-Vinylformamide) [p (HEA/NVF)] was prepared by 60Co-gamma induced copolymerization, using low-temperature radiation technique. Triethylenetetramine(TETA) was applied to modify the prepared hydrogel into an ammoniated hydrogel poly (Hydroxyethyl methacrylate/N-Vinylformamide) -TETA [p (H/V) -T]. The two hydrogels prepared were characterized by using FTIR spectrometry and the p (HEA/NVF) was scanned by SEM. Moreover, the p (H/V) -T hydrogels were analyzed by XPS before and after adsorption. The adsorption capacities of Pb2+, Cd2+ on p (HEA/NVF) and p (H/V)-T were investigated. And the effects of pH, time and initial metal ion concentration on the adsorption of Pb2+, Cd2+ by p (H/V)-T were examined in batch experiments. SEM photos showed that p (HEA/NVF) hydrogel is a macroporous polymer material. Compared to the p (HEA/NVF) hydrogel, the adsorption capacities of Pb2+, Cd2+ on p(H/V)-T increased by 700% and 600%, respectively. The adsorption behaviors for Pb2+ and Cd2+ confirmed that the adsorption on p(H/V)-T followed the pseudo-second-order rate equation and was fitted to both Langmuir and Freundlich adsorption model (R2 > 0.95). Besides, the adsorption capacities of p (H/V)-T increased with increasing pH values. The FTIR spectra verified that p (HEA/NVF) was indeed a copolymer of HEA and NVF monomers, and the multi-amine groups have been successfully grafted to the surface of the copolymer hydrogel. The XPS analysis concluded that the mechanism of Pb2+ and Cd2+ by p (HEA/MALA) could be the chelation between -NH2 and metal ions.

Preparation and evaluation of intravaginal ring containing drospirenone.

In the present study, we investigated the feasibility of the vaginal administration of drospirenone silicone IVR. The in vitro release characteristics of matrix-type and reservoir-type IVR were compared under sink conditions in 21 days. At the same time, API excipients compatibility and preformulation study was performed by HPLC, IR, and DSC methods. Biocompatibility of reservoir system was evaluated by tolerability on tissue level in rats. It was found that, under strong light exposure, high temperature, and high humidity conditions, drospirenone and excipients had no significant interactions. The daily release of reservoir-type IVR was about 0.5 mg/d sustaining 21 days, which significantly decreased the burst effect compared with the matrix system. When drospirenone was modified by the PVPk30 in the reservoir system formulation, the daily release rate increased to 1.0 mg/d sustaining 21 days. The cumulative release of reservoir-type IVR was fitted to zero release equation. In addition, biocompatibility of drospirenone IVR system in this dosage is safe. It is feasibility feasibile to further developed for safe, convenient, and effective contraceptive drug delivery with reduced dosing interval.

Effects of combined exogenous dextranase and sodium fluoride on Streptococcus mutans 25175 monospecies biofilms.

PURPOSE: To investigate the effects of exogenous dextranase and sodium fluoride on a S. mutans monospecies biofilm. METHODS: S. mutans 25175 was grown in tryptone soya broth medium, and biofilm was formed on glass slides with 1.0% sucrose. Exogenous dextranase and sodium fluoride were added alone or together. The biofilm morphology was analyzed by confocal laser scanning microscopy. The effects of the drug on the adhesion and exopolysaccharide production by the biofilms were evaluated by scintillation counting and the anthrone method, respectively. RESULTS: In this study, we found that the structure of initial biofilm and mature biofilm were partly altered by dextranase and high concentrations of sodium fluoride separately. However, dextranase combined with a low concentration of sodium fluoride could clearly destroy the typical tree-like structure of the biofilm, and led to less bacterial adhesion than when the dextranase or fluoride were used alone (P < 0.05). The amounts of soluble and insoluble exopolysaccharide were significantly reduced by combining dextranase with a low concentration of sodium fluoride, much more than when they were used alone (P < 0.05). These data indicate that dextranase and a low concentration of sodium fluoride may have synergistic effects against S. mutans biofilm and suggest the application of a low concentration of sodium fluoride in anticaries treatment.