Characteristics of bone metabolism in postmenopausal female patients with different types of idiopathic benign paroxysmal positional vertigo: A single-centre retrospective study.

OBJECTIVE: The association between benign paroxysmal positional vertigo (BPPV) and impaired calcium metabolism has attracted widespread interest. Several studies have suggested that decreased bone mineral density (BMD) and serum 25-hydroxyvitamin D (25(OH)D) level are related to the occurrence and/or recurrence of BPPV; however, the characteristics of bone metabolism in patients with BPPV subtypes have not been fully investigated, and conclusions have been controversial. This study aimed to evaluate BMD and serum levels of 25(OH)D and bone turnover markers to clarify the characteristics of bone metabolism in patients with different types of BPPV. METHOD: We retrospectively analysed the data of new-onset idiopathic postmenopausal female patients with BPPV at our institution from January 2016 to January 2020. The patients' demographic data including age, medication history, concomitant diseases, onset time, clinical form, laboratory indicators, such as serum levels of 25(OH)D, bone formation markers, namely, amino-terminal propeptide of type I procollagen (PINP) and osteocalcin (OC), bone resorption marker, namely, ß-isomerized carboxy-terminal telopeptide of type I collagen (ß-CTX), and BMD were collected and analysed. RESULTS: This study included 201 consecutive postmenopausal female patients with BPPV. Among them, 138 were diagnosed with posterior semicircular canal BPPV, 42 were diagnosed with lateral semicircular canal canalolithiasis, and 21 were diagnosed with lateral semicircular canal cupulolithiasis. There were no significant differences in age distribution, body mass index, clinical history, levels of albumin, globulin, uric acid, creatinine, or blood urea nitrogen, lipid profiles (except high-density lipoprotein cholesterol) and routine blood parameters among these groups (P > 0.05). There were no significant differences in the mean T-score and BMD values of different sites or in the serum levels of 25(OH)D and bone turnover markers (PINP, OC and ß-CTX) among the subgroups (P > 0.05). The proportion of reduction in BMD (T-score < -1 SD) and decreased serum vitamin D level (< 20 ng/ml) were not significantly different between the subgroups (P > 0.05). CONCLUSION: There were no significant differences in bone metabolism in postmenopausal female patients with different types of idiopathic BPPV.

Investigation of an "alternate water supply system" in enzymatic hydrolysis in the processive endocellulase Cel7A from Rasamsonia emersonii by molecular dynamics simulation.

Cel7A from Rasamsonia emersonii is one of the processive endocellulases classified under family 7 glycoside hydrolase. Molecular dynamics simulations were carried out to obtain the optimized sliding and hydrolyzing conformations, in which the reducing ends of sugar chains are located on different sites. Hydrogen bonds are investigated to clarify the interactions between protein and substrate in either conformation. Nine hydrogen bonding interactions are identified in the sliding conformation, and six similar interactions are also found correspondingly in the hydrolyzing conformation. In addition, four strong hydrophobic interactions are also determined. The domain cross-correlation map analysis shows movement correlation of protein including autocorrelation between residues. The root mean square fluctuations analysis represents the various flexibilities of different fragment in the two conformations. Comparing the two conformations reveals the water-supply mechanism of selective hydrolysis of cellulose in Cel7A. The mechanism can be described as follow. When the reducing end of substrate slides from the unhydrolyzing site (sliding conformation) to the hydrolyzing site (hydrolyzing conformation), His225 is pushed down and rotated, the rotation leads to the movement of Glu209 with the interstrand hydrogen bonding in ß-sheet. It further makes Asp211 close to the hydrolysis center and provides a water molecule bounding on its carboxyl in the previous unhydrolyzing site. After the hydrolysis takes place and the product is excluded from the enzyme, the Asp211 comes back to its initial position. In summary, Asp211 acts as an elevator to transport outer water molecules into the hydrolysis site for every other glycosidic bond.

[Fragile X-associated tremor/ataxia syndrome].

Fragile X-associated tremor/ataxia syndrome(FXTAS) is a neurodegenerative disease caused by FMR1 gene permutation(PM). The main clinical manifestations are intention tremor and/or ataxia, and the pathogenesis was related to RNA toxicity. In this paper, the research progress of clinical manifestatios, pathological characteristics, epidemiology and molecular mechanisms will be reviewed.

Clinicopathological characteristics and prognostic factors of cervical adenocarcinoma.

We aimed to assess the clinicopathological features and to determine the prognostic factors of cervical adenocarcinoma (AC). Relevant data were extracted from surveillance, epidemiology and end results database from 2004 to 2015. The log-rank test and Cox proportional hazard analysis were subsequently utilized to identify independent prognostic factors. A total of 3102 patients were identified. The enrolled patients were characterized by higher proportion of early FIGO stage (stage I: 65.9%; stage II: 14.1%), low pathological grade (grade I/II: 49.1%) and tumor size ≤ 4 cm (46.8%). The 5- and 10-year cancer-specific survival rates of these patients were 74.47% and 70.00%, respectively. Meanwhile, the 5- and 10-year overall survival (OS) rates were 71.52% and 65.17%, respectively. Multivariate analysis revealed that married status, surgery as well as chemotherapy were independent favorable prognostic indicators. Additionally, aged > 45, tumor grade III/IV, tumor size > 4 cm, advanced FIGO stage and pelvic lymph node metastasis (LNM) were unfavorable prognostic factors (all P < 0.01). Stratified analysis found that patients without surgery could significantly benefit from chemotherapy and radiotherapy. In addition, chemotherapy could significantly improve the survival in stage II-IV patients and radiotherapy could only improve the survival in stage III patients (all P < 0.01). Marital status, age, grade, tumor size, FIGO stage, surgery, pelvic LNM and chemotherapy were significantly associated with the prognosis of cervical AC.

Chemical Compounds, Antioxidant Activities, and Inhibitory Activities Against Xanthine Oxidase of the Essential Oils From the Three Varieties of Sunflower (Helianthus annuus L.) Receptacles.

Background/Aim: Essential oils of sunflower receptacles (SEOs) have antibacterial and antioxidant potential. However, the differences of biological activities from the different varieties of sunflowers have not been studied till now. The purpose of this study was to compare the differences of chemical compounds, antioxidant activities, and inhibitory activities against xanthine oxidase (XO) of SEOs from the three varieties of sunflowers including LD5009, SH363, and S606. Methods: SEOs were extracted by using the optimal extraction conditions selected by response surface methodology (RSM). Chemical compounds of SEOs were identified from the three varieties of sunflowers by gas chromatography-mass spectrometry (GC-MS). Antioxidant activities of SEOs were detected by 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), 2,2-diphenyl-1-picrylhydrazyl (DPPH), and iron ion reduction ability. Inhibitory activities of SEOs against XO were measured by using UV spectrophotometer. XO inhibitors were selected from the main chemical compounds of SEOs by the high-throughput selections and molecular simulation docking. Results: The extraction yields of SEOs from LD5009, SH363, and S606 were 0.176, 0.319, and 0.580%, respectively. A total of 101 chemical compounds of SEOs were identified from the three varieties of sunflowers. In addition, the results of inhibitory activities against XO showed that SEOs can reduce uric acid significantly. Eupatoriochromene may be the most important chemical compounds of SEOs for reducing uric acid. The results of antioxidant activities and inhibitory activities against XO showed that SEOs of LD5009 had the strongest antioxidant and XO inhibitory activities. The Pearson correlation coefficient (r > 0.95) showed that γ-terpinene, (E)-citral, and L-Bornyl acetate were highly correlated with the antioxidant activities and XO inhibitory ability. Conclusion: SEOs had antioxidant activities and XO inhibitory ability. It would provide more scientific information for utilization and selection of varieties of sunflowers, which would increase the food quality of sunflowers and incomes of farmers.

Ligand-free copper-catalyzed C(sp3)-H imidation of aromatic and aliphatic methyl sulfides with N-fluorobenzenesulfonimide.

A novel and efficient process has been developed for copper-catalyzed C(sp3)-H direct imidation of methyl sulfides with N-fluorobenzenesulfonimide(NFSI). Without using any ligands, various methyl sulfides including aromatic and aliphatic methyl sulfides, can be transformed to the corresponding N-((phenylthio)methyl)-benzenesulfonamide derivatives in good to excellent yields.

[An enzyme sensor for phenolic compounds analysis].

Phenolic analysis was established on the immobilized horseradish peroxidase (HRP) catalyzed oxidation reaction. It subsequently catalyzed oxidative coupling of phenol with 4-aminophenazone using aqueous hydrogen peroxide to form intensely colored products for spectrophotometric analysis. HRPs were trapped in sol-gel matrix in a mild procedure. The immobilized HRPs maintain almost identical enzymatic activity as those in solution. BET analysis indicates that the silica itself is a porous structure with the average pore diameter of 2.95 nm. It permits small size molecules i. e. hydrogen peroxide, phenol and 4-aminophenazone to diffuse into the matrix while large molecules like enzyme (HRP) remain in the pores. It thus allows a biocatalysis to occur and makes the most out of the enzymes encapsulated in the silica matrix to stand against leakage so that the immobilized horseradish peroxidase could be recycled. The method can be employed for 2-chlorophenol, 3-chlorophenol or 2,4-dichlorophenol analysis as well. The feasibility of recycle on immobilized enzyme is evaluated. Although enzymatic activities are obviously decreased after repeated utilization of 9 times, the method definitely offers a potential spectrophotometric biosensor for phenolic compounds analysis.

miR-144-3p as a novel plasma diagnostic biomarker for clear cell renal cell carcinoma.

OBJECTIVES: Clear cell renal cell carcinoma (ccRCC) is the most frequent and lethal subtype of renal cell carcinoma, whose most effective measure of curing remains diagnosis and nephrectomy in its early phase. However, there is no feasible and recognized plasma biomarker for the clinical diagnosis of ccRCC. The objective of this study is to identify a novel plasma microRNA (miRNA) acting as an efficient diagnostic plasma biomarker in ccRCC. METHODS AND MATERIALS: The plasma miRNA expression profile was quantified by miRNA microarray. Validation of miRNA levels of plasmas and tissues were performed by quantitative reverse transcription polymerase chain reaction in 106 ccRCC, 28 renal angiomyolipomas (AML), and 123 healthy control plasmas and in 110 ccRCC tissues. RESULTS: We found that plasma miR-144-3p levels in 106 ccRCC plasmas were remarkably up-regulated compared with that in healthy individuals and in patients with AML. miR-144-3p served as a promising plasma biomarker for yielding an area under the receiver operating characteristic curve of 0.91 with 87.10% sensitivity and 83.02% specificity in discriminating ccRCC from healthy individuals, and an area under the curve of 0.82 with 75.00% sensitivity and 71.70% specificity in discriminating ccRCC from patients with AML. In addition, plasma miR-144-3p levels were significantly decreased after surgery in 106 patients with ccRCC. Next, we examined miR-144-3p levels in 110 human ccRCC tissues, and found that miR-144-3p levels in ccRCC tissues were increased compared with adjacent normal tissues. Pearson correlation analysis revealed that miR-144-3p levels in tumor tissues were positively correlated with preoperative plasma miR-144-3p levels in the matched samples from patients with ccRCC. In addition, the miR-144-3p levels in ccRCC plasmas and tissues were increased in patients with advanced pT stage. CONCLUSIONS: Our data indicate that miR-144-3p, which is significantly up-regulated in ccRCC plasmas and tissues, particularly with advanced pT stage, is a novel and excellent plasma biomarker for the diagnosis of ccRCC.

Reverse screening approach to identify potential anti-cancer targets of dipyridamole.

Dipyridamole (DIP) inhibits thrombus formation when given chronically, and causes vasodilation over a short time. To date, DIP can increase the anticancer drugs (5-fluorouracil, methotrexate, piperidine, vincristine) concentration in cancer cells and hence enhance the efficacy of treatment cancer. The inhibition of DIP may result in increased 5-fluorouracil efficacy and diminish the drug side effects. But the actual molecular targets remain unknown. In this study, reverse protein-ligands docking, and quantum mechanics were used to search for the potential molecular targets of DIP. The quantum mechanics calculation was performed by using Gaussian 03 program package. Reverse pharmacophore mapping was used to search for potential molecular target candidates for a given small molecule. The docking study was used for exploring the potential anti-cancer targets of dipyridamole. The two predicted binders with the statistically significant prediction are dihydropyrimidine dehydrogenase (DPD) (PDB Id: 1GTE) and human spindle checkpoint kinase Bub1 (PDB Id: 3E7E). Structure analysis suggests that electrostatic interaction and hydrogen bonding play an important role in their binding process. The strong functional linkage of DIP and 5FU supports our prediction. In conclusion, these results generate a tractable set of anticancer proteins. The exploration of polypharmacology will provide us new opportunities in treating systematic diseases, such as the cancers. The results would generate a tractable set of anticancer target proteins for future experimental validations.

Insight into the interactive residues between two domains of human somatic Angiotensin-converting enzyme and Angiotensin II by MM-PBSA calculation and steered molecular dynamics simulation.

Angiotensin-converting enzyme (ACE), a membrane-bound zinc metallopeptidase, catalyzes the formation of Angiotensin-II (AngII) and the deactivation of bradykinin in the renin-angiotensin-aldosterone and kallikrein-kinin systems. As a hydrolysis product of ACE, AngII is regarded as an inhibitor and displays stronger competitive inhibition in the C-domain than the N-domain of ACE. However, the AngII binding differences between the two domains and the mechanisms behind AngII dissociation from the C-domain are rarely explored. In this work, molecular docking, Molecular Mechanics/Poisson-Boltzmann Surface Area calculation, and steered molecular dynamics (SMD) are applied to explore the structures and interactions in the binding or unbinding of AngII with the two domains of human somatic ACE. Calculated free energy values suggest that the C-domain-AngII complex is more stable than the N-domain-AngII complex, consistent with available experimental data. SMD simulation results imply that electrostatic interaction is dominant in the dissociation of AngII from the C-domain. Moreover, Gln106, Asp121, Glu123, and Tyr213 may be the key residues in the unbinding pathway of AngII. The simulation results in our work provide insights into the interactions between the two domains of ACE and its natural peptide inhibitor AngII at a molecular level. Moreover, the results provide theoretical clues for the design of new inhibitors.

Effect of culturing conditions on the expression of key enzymes in the proteolytic system of Lactobacillus bulgaricus.

The proteolytic system of Lactobacillus bulgaricus breaks down milk proteins into peptides and amino acids, which are essential for the growth of the bacteria. The aim of this study was to determine the expressions of seven key genes in the proteolytic system under different culturing conditions (different phases, initial pH values, temperatures, and nitrogen sources) using real-time polymerase chain reaction (RT-PCR). The transcriptions of the seven genes were reduced by 30-fold on average in the stationary phase compared with the exponential growth phase. The transcriptions of the seven genes were reduced by 62.5-, 15.0-, and 59.0-fold in the strains KLDS 08006, KLDS 08007, and KLDS 08012, respectively, indicating that the expressions of the seven genes were significantly different among strains. In addition, the expressions of the seven genes were repressed in the MRS medium containing casein peptone. The effect of peptone supply on PepX transcription was the weakest compared with the other six genes, and the impact on OppD transcription was the strongest. Moreover, the expressions of the seven genes were significantly different among different strains (P<0.05). All these results indicated that the culturing conditions affected the expression of the proteolytic system genes in Lactobacillus bulgaricus at the transcription level.

Genetic association study of glucocerebrosidase gene L444P mutation in essential tremor and multiple system atrophy in mainland China.

The glucocerebrosidase (GBA) gene mutation is emerging as an important risk factor for Parkinson's disease. We previously reported that the GBA gene L444P mutation is an important risk factor for PD in the Chinese population. The prevalence of this mutation in other neurodegenerative diseases and movement disorders remains completely unexplored in mainland China. In the present study, we extended the screening of GBA gene L444P mutation to Chinese patients with essential tremor (ET) and multiple system atrophy (MSA). We searched for the GBA gene L444P mutation in 109 patients with ET, 54 patients with MSA, and 657 controls from mainland China. None of the 109 patients with ET or 54 patients with MSA carried the GBA gene L444P mutation. Among the 657 controls, we found one L444P heterozygote. The difference in mutation frequencies between patients with ET or MSA and the control group was not statistically significant (chi-squared test, p = 1, respectively). The results suggest that the GBA gene L444P mutation may be not responsible for ET in mainland China. Whether the GBA gene L444P mutation modifies the risk for MSA deserves further study in larger samples.

The metabolism of CYP2C9 and CYP2C19 for gliclazide by homology modeling and docking study.

With homology modeling techniques, a 3D structure model of CYP2C19 was built and refined with molecular mechanics and molecular dynamics simulations. The refined model was assessed to be reasonable by Profile-3D and PROCHECK programs. With the aid of the automatic molecular docking, one substrate and two inhibitors were docked to CYP2C19 by InsightII/Affinity program. The docking results, which are in well agreement with the reported results, demonstrate that the refined model of CYP2C19 is reliable. Then, with the refined model of CYP2C19 and the crystal structure of CYP2C9, the metabolisms of them for gliclazide in two different metabolic pathways were studied and the results show that both enzymes have more favorable interaction energies and stronger affinity with gliclazide in methylhydroxylation pathway than in 6beta-hydroxylation pathway. It is exciting that substrate inhibition phenomenon can be found in metabolisms of CYP2C9 and CYP2C19 for gliclazide in two metabolic pathways. Gliclazide can change the conformation of the active sites and decrease obviously the affinities between gliclazide in the active site and enzymes when it is docked in the second active sites in CYP2C9 and CYP2C19. These results are in well agreement with the kinetic experimental results.

Understanding structural/functional properties of amidase from Rhodococcus erythropolis by computational approaches.

The 3D structure of the amidase from Rhodococcus erythropolis (EC 3.5.1.4) built by homology-based modeling is presented. Propionamide and acetamide are docked to the amidase. The reaction models were used to characterize the explicit enzymatic reaction. The calculated free energy barrier at B3LYP/6-31G* level of Model A (Ser194 + propionamide) is 19.72 kcal mol(-1) in gas (6.47 kcal mol(-1) in solution), and of Model B (Ser194 + Gly193 + propionamide) is 18.71 kcal mol(-1) in gas (4.57 kcal mol(-1) in solution). The docking results reveal that propionamide binds more strongly than acetamide due to the ethyl moiety of propionamide, which makes the carboxyl oxygen center of the substrate slightly more negative, making formation of the positively charged tetrahedral intermediate slightly easier. The quantum mechanics results demonstrate that Ser194 is essential for the acyl-intermediate, and Gly193 plays a secondary role in stabilizing acyl-intermediate formation as the NH groups of Ser194 and Gly193 form hydrogen bonds with the carbonyl oxygen of propionamide. The new structural and mechanistic insights gained from this computational study should be useful in elucidating the detailed structures and mechanisms of amidase and other homologous members of the amidase signature family.

Homology modeling of a novel epoxide hydrolase (EH) from Aspergillus niger SQ-6: structure-activity relationship in expoxides inhibiting EH activity.

The 3D structure of a novel epoxide hydrolase from Aspergillus niger SQ-6 (sqEH) was constructed by using homology modeling and molecular dynamics simulations. Based on the 3D model, Asp191, His369 and Glu343 were predicted as catalytic triad. The putative active pocket is a hydrophobic environment and is rich in some important non-polar residues (Pro318, Trp282, Pro319, Pro317 and Phe242). Using three sets of epoxide inhibitors for docking study, the interaction energies of sqEH with each inhibitor are consistent with their inhibitory effects in previous experiments. Moreover, a critical water molecule which closes to the His369 was identified to be an ideal position for the hydrolysis step of the reaction. Two tyrosine residues (Tyr249 and Tyr312) are able to form hydrogen bonds with the epoxide oxygen atom to maintain the initial binding and positioning of the substrate in the active pocket. These docked complex models can well interpret the substrate specificity of sqEH, which could be relevant for the structural-based design of specific epoxide inhibitors.

The 3D structure of the defense-related rice protein Pir7b predicted by homology modeling and ligand binding studies.

To better understand the ligand-binding mechanism of protein Pir7b, important part in detoxification of a pathogen-derived compound against Pyricularia oryzae, a 3D structure model of protein Pir7b was constructed based on the structure of the template SABP2. Three substrates were docking to this protein, two of them were proved to be active, and some critical residues are identified, which had not been confirmed by the experiments. His87 and Leu17 considered as 'oxyanion hole' contribute to initiating the Ser86 nucleophilic attack. Gln187 and Asp139 can form hydrogen bonds with the anilid group to maintain the active binding orientation with the substrates. The docking model can well interpret the specificity of protein Pir7b towards the anilid moiety of the substrates and provide valuable structure information about the ligand binding to protein Pir7b.