Oroxylin a glucuronide as a novel class of reversible inhibitors of Sortase a, combats MRSA-induced infections.

AIMS: The main purpose of this study was to study the therapeutical effect of oroxylin A glucuronide (OAG) on methicillin-resistant Staphylococcus aureus (MRSA). METHODS AND RESULTS: By substrate peptide reaction-based fluorescence resonance energy transfer (FRET) screening, we identified that OAG was an efficient inhibitor of Sortase A (SrtA) with an IC50 of 45.61 µg mL-1, and achieved efficacy in the treatment of Staphylococcus aureus (S. aureus) infections. We further demonstrated that OAG inhibited the adhesion of the S. aureus to fibrinogen, the surface protein A anchoring and diminished biofilm formation. Results obtained from fluorescence quenching assay elucidated a direct interaction between OAG and SrtA. Employing molecular dynamics simulations, we proved that OAG binds to the binding sites of R197, G192, E105, and V168 in the SrtA. Notably, OAG exhibited a robust therapeutic effect in a MRSA-induced pneumonia model. CONCLUSIONS: We identified that OAG as a novel class of reversible inhibitors of SrtA, combats MRSA-induced Infections.

Pharmacokinetics and safety of the two oral cefaclor formulations in healthy chinese subjects in the fasting and postprandial states.

We conducted a phase I bioequivalence trial in healthy Chinese subjects in the fasting and postprandial states. The goal of this trial was to compare the pharmacokinetics and safety of the test preparation Cefaclor granule (Disha Pharmaceutical Group Co., Ltd.) and the reference preparation Cefaclor suspension (Ceclor®, Eli Lilly and Company). In this trial, 24 subjects were selected in the fasting and postprandial states, respectively. Enrolled subjects randomly accepted a single dose of 0.125 g Cefaclor granule or Cefaclor suspension. The washout period was set as 2 days. Blood samples were collected within 8 h after administration in the fasting state and within 10 h after administration in the postprandial state. Plasma concentrations were determined by Liquid chromatography-tandem mass spectrometry (LC-MS/MS). Pharmacokinetic parameters (AUC, Cmax) were used to evaluate bioequivalence of the two drugs. In the fasting trial, the geometric mean ratios (90% confidence intervals CIs) for Cmax, AUC0-t, and AUC0-∞ were 93.01% (85.96%-100.63%), 97.92% (96.49%-99.38%) and 97.95% (96.52%-99.41%), respectively. The GMR (90% CIs) for Cmax, AUC0-t, and AUC0-∞ in postprandial state were 89.27% (81.97%-97.22%), 97.31% (95.98%-98.65%) and 97.31% (95.93%-98.71%), respectively. The 90% CIs of AUC and Cmax in the fasting and postprandial states were within the 80-125% bioequivalence range. Therefore, Cefaclor granule and Cefaclor suspension were bioequivalent and displayed similar safety profiles. Furthermore, food intake affected the pharmacokinetic parameters of both drugs.

7,8-Dihydroxyflavone attenuates the virulence of Staphylococcus aureus by inhibiting alpha-hemolysin.

Staphylococcus aureus (S. aureus), a Gram-positive bacteria, is an incurable cause of hospital and community-acquired infections. Inhibition bacterial virulence is a viable strategy against S. aureus infections based on the multiple virulence factors secreted by S. aureus. Alpha-hemolysin (Hla) plays a crucial role in bacteria virulence without affecting bacterial viability. Here, we identified that 7,8-Dihydroxyflavone (7,8-DHF), a natural compound, was able to decrease the expression of and did not affect the in vitro growth of S. aureus USA300 at a concentration of 32 µg/mL. It was verified by western blot and RT-qPCR that the natural compound could inhibit the transcription and translation of Hla. Further mechanism studies revealed that 7,8-DHF has a negative effect on transcriptional regulator agrA and RNAIII, preventing the upregulation of virulence gene. Cytotoxicity assays showed that 7,8-DHF did not produce significant cytotoxicity to A549 cells. Animal experiments showed that the combination of 7,8-DHF and vancomycin had a more significant therapeutic effect on S. aureus infection, reflecting the synergistic effect of 7,8-DHF with antibiotics. In conclusion, 7,8-DHF was able to target Hla to protect host cells from hemolysis while limiting the development of bacterial resistance.

RDAU-Net: Based on a Residual Convolutional Neural Network With DFP and CBAM for Brain Tumor Segmentation.

Due to the high heterogeneity of brain tumors, automatic segmentation of brain tumors remains a challenging task. In this paper, we propose RDAU-Net by adding dilated feature pyramid blocks with 3D CBAM blocks and inserting 3D CBAM blocks after skip-connection layers. Moreover, a CBAM with channel attention and spatial attention facilitates the combination of more expressive feature information, thereby leading to more efficient extraction of contextual information from images of various scales. The performance was evaluated on the Multimodal Brain Tumor Segmentation (BraTS) challenge data. Experimental results show that RDAU-Net achieves state-of-the-art performance. The Dice coefficient for WT on the BraTS 2019 dataset exceeded the baseline value by 9.2%.

DFP-ResUNet:Convolutional Neural Network with a Dilated Convolutional Feature Pyramid for Multimodal Brain Tumor Segmentation.

BACKGROUND AND OBJECTIVE: Manual brain tumor segmentation by radiologists is time consuming and subjective. Therefore, fully automatic segmentation of different brain tumor subregions is essential to the treatment of patients. In this paper, we propose a neural network for automatically segmenting the enhancing tumor (ET), whole tumor (WT), and tumor core (TC) brain tumor subregions. METHODS: The network is based on a U-Net with encoding and decoding structure, a residual module, and a spatial dilated feature pyramid (DFP) module, namely, DFP-ResUNet. First, we propose using a spatial DFP module composed of multiple parallel dilated convolution layers to extract the multiscale image features. This spatial DFP structure improves the ability of the neural network to extract and utilize the multiscale image features. Then, we use the residual module to deepen the network structure. Further, we propose using a multiclass Dice loss function to suppress the impact of class imbalance on brain tumor segmentation. We carried out a large number of ablation experiments to verify the feasibility and superiority of our approach using the Multimodal Brain Tumor Segmentation (BraTS) challenge dataset. RESULTS: The mean Dice score of different subregions was ET 0.8431, WT 0.897 and TC 0.9068 using the proposed method on the BraTS 2018 challenge validation set and 0.7985, 0.90281, 0.8453 on the BraTS 2019 challenge, respectively. Further, we got a high Sensitivity and Specificity and low Hausdorff distance. CONCLUSIONS: Through the analysis of the experimental results, it can be seen that the proposed approach DFP-ResUNet has a great potential in segmenting different subregions of brain tumors and can be applied in clinical practice.

The genomic underpinnings of apoptosis in the silkworm, Bombyx mori.

BACKGROUND: Apoptosis is regulated in an orderly fashion by a series of genes, and has a crucial role in important physiological processes such as growth development, immunological response and so on. Recently, substantial studies have been undertaken on apoptosis in model animals including humans, fruit flies, and the nematode. However, the lack of genomic data for silkworms limits their usefulness in apoptosis studies, despite the advantages of silkworm as a representative of Lepidoptera and an effective model system. Herein we have identified apoptosis-related genes in the silkworm Bombyx mori and compared them to those from insects, mammals, and nematodes. RESULTS: From the newly assembled genome databases, a genome-wide analysis of apoptosis-related genes in Bombyx mori was performed using both nucleotide and protein Blast searches. Fifty-two apoptosis-related candidate genes were identified, including five caspase family members, two tumor necrosis factor (TNF) superfamily members, one Bcl-2 family member, four baculovirus IAP (inhibitor of apoptosis) repeat (BIR) domain family members and 1 RHG (Reaper, Hid, Grim, and Sickle; Drosophila cell death activators) family member. Moreover, we identified a new caspase family member, BmCaspase-New, two splice variants of BmDronc, and Bm3585, a mammalian TNF superfamily member homolog. Twenty-three of these apoptosis-related genes were cloned and sequenced using cDNA templates isolated from BmE-SWU1 cells. Sequence analyses revealed that these genes could have key roles in apoptosis. CONCLUSIONS: Bombyx mori possesses potential apoptosis-related genes. We hypothesized that the classic intrinsic and extrinsic apoptotic pathways potentially are active in Bombyx mori. These results lay the foundation for further apoptosis-related study in Bombyx mori.