Structural and molecular basis for urea recognition by Prochlorococcus.

Nitrogen (N) is an essential element for microbial growth and metabolism. The growth and reproduction of microorganisms in more than 75% of areas of the ocean are limited by N. Prochlorococcus is numerically the most abundant photosynthetic organism on the planet. Urea is an important and efficient N source for Prochlorococcus. However, how Prochlorococcus recognizes and absorbs urea still remains unclear. Prochlorococcus marinus MIT 9313, a typical Cyanobacteria, contains an ABC-type transporter, UrtABCDE, which may account for the transport of urea. Here, we heterologously expressed and purified UrtA, the substrate-binding protein of UrtABCDE, detected its binding affinity toward urea, and further determined the crystal structure of the UrtA/urea complex. Molecular dynamics simulations indicated that UrtA can alternate between "open" and "closed" states for urea binding. Based on structural and biochemical analyses, the molecular mechanism for urea recognition and binding was proposed. When a urea molecule is bound, UrtA undergoes a state change from open to closed surrounding the urea molecule, and the urea molecule is further stabilized by the hydrogen bonds supported by the conserved residues around it. Moreover, bioinformatics analysis showed that ABC-type urea transporters are widespread in bacteria and probably share similar urea recognition and binding mechanisms as UrtA from P. marinus MIT 9313. Our study provides a better understanding of urea absorption and utilization in marine bacteria.

Preoperative Diagnosis of Dual-Phenotype Hepatocellular Carcinoma Using Enhanced MRI Radiomics Models.

BACKGROUND: Dual-phenotype hepatocellular carcinoma (DPHCC) is highly aggressive and difficult to distinguish from hepatocellular carcinoma (HCC). PURPOSE: To develop and validate clinical and radiomics models based on contrast-enhanced MRI for the preoperative diagnosis of DPHCC. STUDY TYPE: Retrospective. POPULATION: A total of 87 patients with DPHCC and 92 patients with non-DPHCC randomly divided into a training cohort (n = 125: 64 non-DPHCC; 61 DPHCC) and a validation cohort (n = 54: 28 non-DPHCC; 26 DPHCC). FIELD STRENGTH/SEQUENCE: A 3.0 T; dynamic contrast-enhanced MRI with time-resolved T1-weighted imaging sequence. ASSESSMENT: In the clinical model, the maximum tumor diameter and hepatitis B virus (HBV) were independent risk factors of DPHCC. In the radiomics model, a total of 1781 radiomics features were extracted from tumor volumes of interest (VOIs) in the arterial phase (AP) and portal venous phase (PP) images. For feature reduction and selection, Pearson correlation coefficient (PCC) and recursive feature elimination (RFE) were used. Clinical, AP, PP, and combined radiomics models were established using machine learning algorithms (support vector machine [SVM], logistic regression [LR], and logistic regression-least absolute shrinkage and selection operator [LR-LASSO]) and their discriminatory efficacy assessed and compared. STATISTICAL TESTS: The independent sample t test, Mann-Whitney U test, Chi-square test, regression analysis, receiver operating characteristic curve (ROC) analysis, Pearson correlation analysis, the Delong test. A P value < 0.05 was considered statistically significant. RESULTS: In the validation cohort, the combined radiomics model (area under the curve [AUC] = 0.908, 95% confidence interval [CI]: 0.831-0.985) showed the highest diagnostic performance. The AUCs of the PP (AUC = 0.879, 95% CI: 0.779-0.979) and combined radiomics models were significantly higher than that of clinical model (AUC = 0.685, 95% CI: 0.526-0.844). There were no significant differences in AUC between AP or PP radiomics model and combined radiomics model (P = 0.286, 0.180 and 0.543). CONCLUSION: MRI radiomics models may be useful for discriminating DPHCC from non-DPHCC before surgery. EVIDENCE LEVEL: 4 TECHNICAL EFFICACY: Stage 2.

Metal-Controlled Switchable Regioselective Synthesis of Substituted Imidazoles and Pyrroles via Ring Opening/Cyclocondensation with 2H-Azirines.

Catalytic selective annulation of 2H-azirines constitutes a general and modular strategy for the generation of molecular complexity. By using Pd-catalyzed ring opening/heterocyclization associated with direct cleavage of C-N and C-C bonds under appropriate conditions, the formation of imidazoles is presented. Alternatively, the silver-catalyzed radical [3 + 2] cycloannulation of 2H-azirines and 1,3-dicarbonyl compounds provides highly functionalized pyrrole derivatives. Both aliphatic cyclic and acyclic diketones are tolerated with good regioselectivity. Moreover, a radical capture experiment was carried out to determine the proposed mechanism, providing support for a facile radical process.

Synthesis of (E)-2-(1-(methoxyimino)ethyl)-2-phenylbenzofuran-3(2H)-ones from (E)-1-(benzofuran-2-yl)ethan-1-one O-methyl oximes and iodobenzenes via a palladium-catalyzed dearomative arylation/oxidation reaction.

A new method has been successfully developed that offers a facile and reliable approach for synthesizing (E)-2-(1-(methoxyimino)ethyl)-2-phenylbenzofuran-3(2H)-one, providing 28 compounds. This optimized process enables efficient preparation of a wide range of compounds using readily available (E)-1-(benzofuran-2-yl)ethan-1-one O-methyl oxime and iodobenzene, and provides alternative ideas for the structural modification of benzofuran ketones.

Hypoxia-induced miR-9 expression promotes ovarian cancer progression via activating PI3K/AKT/mTOR/GSK3ß signaling pathway.

Ovarian cancer (OC) is one of the most prevalent malignant tumors affecting women's life and health. Since OC has a poor prognosis due to extensive metastasis, there is a need to explore a new mechanism of OC metastasis. microRNAs (miRs) are single-stranded, non-coding RNAs. miR-9 has been reported to promote cancer and may provide a new strategy for OC diagnosis. The purpose of this study was to examine the function and underlying mechanism of miR-9 in OC. RT-qPCR was used to assess miR-9 expression levels. Transwell assays were used to determine the number of migrating and invading OC cells. The protein expression levels of the PI3K/AKT/mTOR/GSK3ß signaling pathway were examined using western blotting. The results informed that, when compared to normal ovarian tissues, miR-9 was remarkably expressed in OC tissues, and hypoxia might lead to overexpression of miR-9-5p while inhibiting miR-9 notably suppressed the migrating and invading cell numbers in OC cells. In vivo, miR-9-5p knockdown inhibited tumor growth in a subcutaneous nude mice model of SKOV3 cells. Our findings suggest that miR-9 could be an underlying oncogene in OC, opening up new avenues for OC diagnosis and treatment of OC by targeting miR-9.

A systematic review of cross-cultural adaptation of the National Institutes of Health Chronic Prostatitis Symptom Index.

BACKGROUND: The National Institutes of Health Chronic Prostatitis Symptom Index (NIH-CPSI) was developed to accurately assess the pain, urinary symptoms, and quality of life related to chronic prostatitis/chronic pelvic pain syndrome (CP/CPPS). This study aimed to evaluate the cross-cultural adaptations of the NIH-CPSI. METHOD: PubMed, Embase, CINAHL, and SciELO databases were searched from their established year to September 2020. Cross-cultural adaptations and the quality control of measurement properties of adaptations were conducted by two reviewers independently according to the Guidelines for the Process of Cross-Cultural Adaptation of Self-Report Measures and the Quality Criteria for Psychometric Properties of Health Status Questionnaire. RESULTS: Area total of 21 papers with 16 adaptations, and six studies of the original version of the NIH-CPSI were enrolled in the systematic review. Back translation was the weakest process for the quality assessment of the cross-cultural adaptations of the NIH-CPSI. Internal consistency was analyzed for most of the adaptations, but none of them met the standard. Only 11 adaptations reported test reliability, then only the Arabic-Egyptian, Chinese-Mainland, Danish, Italian, Persian, and Turkish adaptations met the criterion. Most adaptations reported the interpretability, but only the Danish adaptation reported the agreement. The other measurement properties, including responsiveness, and floor as well as ceiling effects were not reported in any of the adaptations. CONCLUSIONS: The overall quality of the NIH-CPSI cross-cultural adaptations was not organized as expected. Only the Portuguese-Brazilian, Italian, and Spanish adaptations reached over half the process for the cross-cultural adaptation. Only the Turkish adaptations finished half of the measurement properties of cross-cultural adaptations.

Risk factors for electrocardiographic left ventricular hypertrophy in a young Chinese general population: the Hanzhong adolescent cohort study.

BACKGROUND: Electrocardiographic left ventricular hypertrophy (ECG-LVH) is a common manifestation of preclinical cardiovascular disease. The present study aimed to investigate risk factors for ECG-LVH and its prevalence in a cohort of young Chinese individuals. METHODS: (1) A total of 1515 participants aged 36-45 years old from our previously established cohort who were followed up in 2017 were included. Cross-sectional analysis was used to examine risk factors for ECG-LVH and its prevalence. (2) A total of 235 participants were recruited from the same cohort in 2013 and were followed up in 2017. Longitudinal analysis was used to determine the predictors of LVH occurrence over the 4-year period. We used multivariable logistic regression models to calculate OR and 95% CIs and to analyze risk factors for ECG-LVH. RESULTS: In the cross-sectional analysis, the prevalence of LVH diagnosed by the Cornell voltage-duration product in the overall population and the hypertensive population was 4.6% and 8.8%, respectively. The logistic regression results shown that female sex [2.611 (1.591-4.583)], hypertension [2.638 (1.449-4.803)], systolic blood pressure (SBP) [1.021 (1.007-1.035)], serum uric acid (SUA) [1.004 (1.001-1.006)] and carotid intima-media thickness (CIMT) [67.670 (13.352-342.976)] were significantly associated with the risk of LVH (all P < 0.05). In the longitudinal analysis, fasting glucose [1.377 (1.087-1.754)], SBP [1.046 (1.013-1.080)] and female sex [1.242 (1.069-1.853)] were independent predictors for the occurrence of LVH in the fourth year of follow-up. CONCLUSIONS: Our study suggested that female sex, hypertension, SBP, SUA and CIMT were significantly associated with the risk of LVH in young people. In addition, fasting glucose, SBP and female sex are independent predictors of the occurrence of LVH in a young Chinese general population.

MDMPR: Mouse Developmental and Metabolic Phenotype Repository.

Mouse Developmental and Metabolic Phenotype Repository (MDMPR) is an open access, real-time database which dedicates to share mouse resources and phenotype data. MDMPR is supported by the National Key Research and Development Project "Establishment of Mouse Developmental and Metabolic Phenotype Repository" within the Key Project of "Developmental Programming and Its Metabolic Regulation" from the Ministry of Science and Technology of the People's Republic of China's program. In the next 5 years, MDMPR will create 500 mutant mouse models related to development and metabolism, perform standard phenotyping analysis, and establish a phenotype database. MDMPR is a combination of resources and data repository, has several sub-systems, including the ES cell database, the project management system, the breeding management system, the sperm bank management system and the phenotyping database. These systems digitalize all data and ensure their authenticity in real-time. Besides the gradual increase of data during the project, MDMPR will also integrate other resources, such as human KO ES cell database, STRING database, database of Core Transcriptional Regulatory Circuitries and Enhancer-Indel database. MDMPR is anticipated to contribute to various areas of developmental and metabolic research to investigators through more convenient accesses to the resources and data in one-stop manner, thereby accelerating the research processes and ultimately serving the medical causes of human health.

Synthesis of Chiral Bis(3-indolyl)methanes Bearing a Trifluoromethylated All-Carbon Quaternary Stereocenter via Nickel-Catalyzed Asymmetric Friedel-Crafts Alkylation Reaction.

Bis(3-indolyl)methanes are well-known natural products with a broad range of important biological functions including cancer cell growth inhibition and antimicrobial activity. Incorporation of a trifluoromethyl group is known to have a profound effect on the parent compound's biological activities. Here, an efficient method for the synthesis of chiral trifluoromethylated bis(3-indolyl)methanes via a catalytic asymmetric Friedel-Crafts (F-C) alkylation reaction has been established. Both enantiomers of the catalysis products can be obtained by tuning the chiral substituents of the catalyst. With 5 mol % of the Ni(II)/(imidazoline-oxazoline) complex as the catalyst, the F-C reaction of indoles with ß-CF3-ß-(3-indolyl)nitroalkenes proceeded well to afford a series of chiral bis(3-indolyl)methanes bearing a trifluoromethylated all-carbon quaternary stereocenter in generally good yields with excellent enantioselectivities (up to 98% yield and 94% ee). Furthermore, by interchanging the indole moieties of the two reactants, indole vs ß-CF3-ß-(3-indolyl)nitroalkene in the F-C reaction, both enantiomers of a given trifluoromethylated bis(3-indolyl)methane were obtained with high enantioselectivities (89-94% ee) upon removal of the indole N-protecting group in the F-C products. The current work represents the first general catalytic enantioselective approach to the important class of trifluoromethylated bis(3-indolyl)methanes.

Rhodium-catalyzed synthesis of substituted isoquinolones via a selective decarbonylation/alkyne insertion cascade of phthalimides.

A rhodium-catalyzed decarbonylation/alkyne insertion cascade of phthalimides has been established. The reaction can be carried out in an operationally simple manner and provides expedient access to a series of isoquinolones in moderate to good yields. This reaction proceeded through a sequential decarbonylation/alkyne insertion/intramolecular annulation procedure and featured good functional group tolerance, ample substrate scope, and the construction of C-C and C-N bonds in one pot.

Asymmetric Michael Addition of 2-Acetyl Azaarenes to ß-CF3-ß-(3-indolyl)nitroalkenes Catalyzed by a Cobalt(II)/(imidazoline-oxazoline) Complex.

The first enantioselective Michael addition of 2-acetyl azaarenes to ß-CF3-ß-(3-indolyl)nitroalkenes has been successfully achieved in the presence of a Co(II)/(imidazoline-oxazoline) complex as the catalyst. The reaction affords a series of CF3- and 3-indole-containing adducts featuring a trifluoromethylated all-carbon quaternary stereocenter in good to excellent yields (up to 99%) and enantioselectivities (up to 96% ee). Furthermore, the functional groups in the adducts including C═O, NO2, and the azaarene provide a large variety of useful transformations, leading to the formation of valuable intermediates such as optically active secondary alcohol, pyrroline, ester, and pyrrolidinone which all contain a 3-substituted indole and a trifluoromethylated all-carbon quaternary stereocenter.

Synthesis and Evaluation of 3-Substituted-4-(quinoxalin-6-yl) Pyrazoles as TGF-ß Type I Receptor Kinase Inhibitors.

The transforming growth factor-ß (TGF-ß), in which overexpression has been associated with various diseases, has become an attractive molecular target for the treatment of cancers. Thirty-two quinoxaline-derivatives of 3-substituted-4-(quinoxalin-6-yl) pyrazoles 14a⁻d, 15a⁻d, 16a⁻d, 17a⁻d, 18a⁻d, 19a⁻d, 25a, 25b, 25d, 26a, 26b, 26d, 27b, and 27d were synthesized and evaluated for their activin TGF-ß type I receptor kinase and p38α mitogen activated protein (MAP) kinase inhibitory activity in enzymatic assays. Among these compounds, the most active compound 19b inhibited TGF-ß type I receptor kinase phosphorylation with an IC50 value of 0.28 µM, with 98% inhibition at 10 µM. Compound 19b also had good selectivity index of >35 against p38α MAP kinase, with 9.0-fold more selective than clinical candidate, compound 3 (LY-2157299). A molecular docking study was performed to identify the mechanism of action of the synthesized compounds and their good binding interactions were observed. ADMET prediction of good active compounds showed that these ones possess good pharmacokinetics and drug-likeness behavior.

[Study on the polarized reflectance characteristics of single greenhouse tomato nutrient deficiency leaves].

In order to improve accuracy of quantitative analysis model for the greenhouse tomato nitrogen, phosphorus and potassium nutrient stress, and explore the advantages of polarization non-destructive detection in single-leaf plants scale, polarized reflectance characteristics of greenhouse nutrient deficiency tomato leaves in different growing seasons and different deficiency extents were both examined via means of polarized reflectance spectroscopy system, which was self-developed by the research group. The main factors with effects on the polarized reflectance characteristics of tomato leaves were discussed, such as incident zenith angle, azimuth angle, detection zenith angle, light source polarizer degree, and detector polarizer degree. Experiments were carried out to verify the optimum level of above five parameters by means of range analysis of orthogonal experiments, through that way we can know the best angle combination of five parameters. Based on the above analysis, the angle combination and sorting of detecting tomato nutrients deficiency leaves via means of polarization spectroscopy system were obtained as follows: incident zenith angle 60 degrees, light source polarizer degree 0 degrees, detection zenith angle 45 degrees, detector polarizer degree 45 degrees and azimuth angle 180 degrees. At the same time, both the spectra of nitrogen, phosphorus and potassium deficiency leaves in different growth stages and different deficiency extent leaves were compared with each other. Results show that there is a positive correlation between the greenhouse nutrient deficiency tomato leaves growth cycle and tomato leaves polarized reflectance spectra. Nutrient excess or nutrient deficiency can both lead to polarized reflectance decline and polarized reflectance decline extent of greenhouse tomato leaves is more obvious during the fruiting and harvest period. This paper has a certain theoretical and practical significance in the research on nutrition rapid detection on the plant single leaf scale by means of polarized reflectance spectrum.

[Study on the polarized reflectance-hyperspectral information fusion technology of tomato leaves nutrient diagnoses].

With 25%, 50%, 75%, 100% and 150%, five levels of, nitrogen (N), phosphorus (P) and potassium (K) nutrition stress samples cultivated in Venlo type greenhouse soilless cultivation mode as the research object, polarized reflectance spectra and hyperspectral images of different nutrient deficiency greenhouse tomato leaves were acquired by using polarized reflectance spectroscopy system developed by our own research group and hyperspectral imaging system respectively. The relationship between a certain number of changes in the bump and texture of non-smooth surface of the nutrient stress leaf and the level of polarization reflected radiation was clarified by scanning electron microscopy (SEM). On the one hand, the polarization spectrum was converted into the degree of polarization through Stokes equation, and the four polarization characteristics between the polarization spectroscopy and reference measurement values of N, P and K respectively were extracted. On the other hand, the four characteristic wavelengths of N, P, K hyperspectral image data were determined respectively through the principal component analysis, followed by eight hyperspectral texture features extracted corresponding to the four characteristic wavelengths through correlation analysis. Polarization characteristics and hyperspectral texture features combined with each characteristics of N, P, K were extracted. These 12 characteristic variables were normalized by maximum-minimum value method. N, P, K nutrient levels quantitative diagnostic models were established by SVR. Results of models are as follows: the correlation coefficient of nitrogen r = 0.961 8, root mean square error RMSE= 0.451; correlation coefficient of phosphorus r = 0.916 3, root mean square error RMSE = 0.620; correlation coefficient of potassium r = 0.940 6, root mean square error RMSE = 0.494. The results show that high precision tomato leaves nutrition prediction model could be built by using polarized reflectance spectroscopy combined with high spectral information fusion technology and achieve good diagnoses effect. It has a great significance for the improvement of model accuracy and the development of special instruments. The research provides a new idea for the rapid detection of tomato nutrient content.

Thioproline-Based Oxidation Strategy for Direct Preparation of N-Terminal Thiazolidine-Containing Peptide Thioesters from Peptide Hydrazides.

We describe a simple and robust oxidation strategy for preparing N-terminal thiazolidine-containing peptide thioesters from peptide hydrazides. We find for the first time that l-thioproline can be used as a protective agent to prevent the nitrosation of N-terminal thiazolidine during peptide hydrazide oxidation. The thioproline-based oxidation strategy has been successfully applied to the chemical synthesis of CC chemokine ligand-2 (69aa) and omniligase-C (113aa), thereby demonstrating its utility in hydrazide-based native chemical ligation.

Asparaginyl Endopeptidase-Mediated Peptide Cyclization for Phage Display.

We report here an enzymatic strategy for asparaginyl endopeptidase-mediated peptide cyclization. Incorporation of chloroacetyl groups into the recognition sequence of OaAEP1 enabled intramolecular cyclization with Cys residues. Combining this strategy and phage display, we identified nanomolar macrocyclic peptide ligands targeting TEAD4. One of the bicyclic peptides binds to TEAD4 with a KD value of 139 nM, 16 times lower than its linear analogue, demonstrating the utility of this platform in discovering high-affinity macrocyclic peptide ligands.

Dupilumab for treatment of severe atopic dermatitis accompanied by lichenoid amyloidosis in adults: Two case reports.

BACKGROUND: Lichenoid amyloidosis (LA) is a subtype of primary cutaneous amyloidosis characterized by persistent multiple groups of hyperkeratotic papules, usually on the lower leg, back, forearm, or thigh. LA may be associated with several skin diseases, including atopic dermatitis (AD). The treatment of LA is considered to be difficult. However, as there is some overlap in the etiopathogenesis of LA and AD, AD treatment may also be effective for LA. CASE SUMMARY: Case 1: A 70-year-old man was diagnosed with severe AD with LA based on large dark erythema and papules on the trunk and buttocks and dense hemispherical millet-shaped papules with pruritus on the extensor side of the lower limbs. He had a long history of the disease (8 years), with repeated and polymorphic skin lesions. Given the poor efficacy of traditional treatments, this patient was recommended to receive dupilumab treatment. At the initial stage, 300 mg was injected subcutaneously every 2 wk. After 28 wk, the drug interval was extended to 1 mo due to the pandemic. Follow-up observations revealed that the patient reached an Eczema Area Severity Index of 90 (skin lesions improved by 90% compared with the baseline) by the end of the study. Moreover, Investigator's Global Assessment score was 1, and scoring atopic dermatitis index and numeric rating scale improved by 97.7% and 87.5% compared with the baseline, respectively, with LA skin lesions having largely subsided. Case 2: A 30-year-old woman was diagnosed with severe AD with LA, due to dense and substantial papules on the dorsal hands similar to changes in cutaneous amyloidosis, and erythema and papules scattered on limbs and trunk with pruritus, present for 25 years. After 16 wk of dupilumab treatment, she stopped, and skin lesions completely subsided, without recurrence since the last follow-up. CONCLUSION: Dupilumab shows rational efficacy and safety in the treatment of severe AD with LA, in addition to benefits in the quality of life of the patients.

[Imaging findings of carcinoma ex pleomorphic adenoma in minor salivary glands].

PURPOSE: To summarize the CT and MR imaging features of carcinoma ex pleomorphic adenoma(Ca-ex-PA) in minor salivary gland, and analyze the correlation between various features and pathological classification. METHODS: Forty-three patients with Ca-ex-PA in minor salivary gland were collected. The CT and MRI findings were retrospectively analyzed and correlated with their pathological types. Fisher's exact test was used to analyze the correlation between various imaging features (tumor morphology, boundary, internal structure, bone invasion, cervical lymph node metastasis) and pathological types with SPSS 25.0 software package. RESULTS: Among the 43 patients with Ca-ex-PA, 83.7%(36/43) of the tumors were lobulated; 81.4%(35/43) showed cystic degeneration or necrosis, with heterogeneous enhancement. Coarse calcification or mixed calcification was found in 37.2%(16/43), 25.6%(11/43) had compressive absorption of adjacent bone. 75%(12/16) of type Ⅰ/Ⅱ tumors had regular morphology (round or oval), and 77.8%(21/27) of type Ⅲ tumors had irregular morphology, 93.8%(15/16) of type Ⅰ/Ⅱ tumors had well-defined margin and 66.7%(18/27) of type Ⅲ tumors had ill-defined margin. Osteolytic bone resorption occurred in 59.3%(16/27) of type Ⅲ tumors. The average maximum diameter of type Ⅰ/Ⅱ tumors was significantly shorter than that of type Ⅲ(P＜0.05). Fisher's exact test showed the characteristics of tumor morphology, boundary and osteolytic bone resorption were related to pathological grouping(P＜0.001). CONCLUSIONS: Most Ca-ex-PA in minor salivary glands is characterized by lobular and heterogeneous enhanced neoplasm on CT and MR imaging. A round or oval tumor with well-defined margin usually correlates with typeⅠ and Ⅱ, contrarily, an irregular mass with ill-defined margin and osteolytic bone destruction usually correlates with type Ⅲ. Combining the three characteristics of morphology, boundary and osteolysis is more helpful to distinguish type Ⅰ/Ⅱ and type Ⅲ tumors.

[MRI findings of parotid acinic cell carcinoma in 19 consecutive cases].

PURPOSE: To describe the MRI features of acinar cell carcinoma of parotid gland (AciCC) and to evaluate the diagnostic value of MR functional imaging. METHODS: A total of 269 cases of maxillofacial AciCC confirmed by surgery and pathology were analyzed. Among them, nineteen subjects with AciCC in the parotid gland underwent preoperative MRI examination (non-enhanced scan for one case, enhanced scan for 18 cases), seventeen patients underwent diffusion-weighted imaging scan, and 15 patients underwent dynamic contrast-enhanced scan. MRI findings of 19 patients were retrospectively analyzed. The lesion size, location, morphology, margin, internal composition, enhancement pattern and functional imaging characteristics were analyzed. SPSS 25.0 software package was used for statistical analysis. RESULTS: Among 269 cases of maxillofacial AciCC, there were 108 males and 161 females, male: female = 1:1.49, aged from 4 to 89 years, with a mean age of (45.95±17.33) years. 84.4% (227/269) were located in the parotid gland. On MRI images, 78.9% (15/19) had well-defined margin, 57.9% (11/19) were round or oval, and 36.8% (7/19) were lobed nodules. One case had irregular morphology and peripheral invasion. The range of maximum diameter was 6-56 mm, averaging (24.8±15.3) mm. Internal composition showed 57.9% (11/19) were cystic solid, 42.1% (8/19) were solid, 31.6% (6/19) had bleeding. T2-weighted MRI showed 52.6% (10/19) with envelope structure, 15.8% (3/19) with low signal separation inside, 38.9%(7/18) had uniform enhancement, and 61.1%(11/18) had uneven enhancement. Functional imaging showed the mean ADC value of tumor was (1.026±0.194)×10-3 mm2/s(n=17). 86.7%(13/15) TIC was type Ⅱ. CONCLUSIONS: Most maxillofacial AciCC are located in the parotid gland. It is difficult to distinguish AciCC from benign tumors with conventional MRI in morphology. The ADC value of AciCC is lower than that of benign tumors, and the type of TIC curve is mostly type Ⅱ. Combination of morphology and functional imaging can improve the diagnostic accuracy of this disease.