Nicotinamide mononucleotide supplementation improves the quality of porcine oocytes under heat stress

Background:Elevated ambient temperature-caused heat stress is a major concern for livestock production due to its negative impact on animal feed intake,growth,reproduction,and health.Particularly,the germ cells are extremely sensitive to the heat stress.However,the effective approach and strategy regarding how to protect mammalian oocytes from heat stress-induced defects have not been determined.Methods:Germinal vesicle(GV)porcine oocytes were cultured at 41.5℃ for 24 h to induce heat stress,and then cultured at 38.5℃ to the specific developmental stage for subsequent analysis.Nicotinamide mononucleotide(NMN)was dissolved in water to 1 mol/L for a stock solution and further diluted with the maturation medium to the final concentrations of 10μmol/L,20μmol/L,50μmol/L or 100μmol/L,respectively,during heat stress.Immunostaining and fluorescence intensity quantification were applied to assess the effects of heat stress and NMN supplementation on the key processes during the oocyte meiotic maturation.Results:Here,we report that NMN supplementation improves the quality of porcine oocytes under heat stress.Specifically,we found that heat stress resulted in oocyte maturation failure by disturbing the dynamics of meiotic organelles,including the cytoskeleton assembly,cortical granule distribution and mitochondrial function.In addition,heat stress induced the production of excessive reactive oxygen species(ROS)and DNA damage,leading to the occurrence of apoptosis in oocytes and subsequent embryonic development arrest.More importantly,we validated that supplementation of NMN during heat stress restored the meiotic defects during porcine oocyte maturation.Conclusions:Taken together,our study documents that NMN supplementation is an effective approach to improve the quality of oocytes under heat stress by promoting both nuclear and cytoplasmic maturation.

Acquisition repeatability of MRI radiomics features in the head and neck:a dual-3D-sequence multi-scan study

Radiomics has increasingly been investigated as a potential biomarker in quantitative imaging to facilitate personalized diagnosis and treatment of head and neck cancer(HNC),a group of malignancies associated with high heterogeneity.However,the feature reliability of radiomics is a major obstacle to its broad validity and generality in application to the highly heterogeneous head and neck(HN)tissues.In particular,feature repeatability of radiomics in magnetic resonance imaging(MRI)acquisition,which is considered a crucial confounding factor of radiomics feature reliability,is still sparsely investigated.This study prospectively investigated the acquisition repeatability of 93 MRI radiomics features in ten HN tissues of 15 healthy volunteers,aiming for potential magnetic resonance-guided radiotherapy(MRgRT)treatment of HNC.Each subject underwent four MRI acquisitions with MRgRT treatment position and immobilization using two pulse sequences of 3D T1-weighed turbo spin-echo and 3D T2-weighed turbo spin-echo on a 1.5T MRI simulator.The repeatability of radiomics feature acquisition was evaluated in terms of the intraclass correlation coefficient(ICC),whereas within-subject acquisition variability was evaluated in terms of the coefficient of variation(CV).The results showed that MRI radiomics features exhibited heterogeneous acquisition variability and uncertainty dependent on feature types,tissues,and pulse sequences.Only a small fraction of features showed excellent acquisition repeatability(ICC>0.9)and low within-subject variability.Multiple MRI scans improved the accuracy and confidence of the identification of reliable features concerning MRI acquisition compared to simple test-retest repeated scans.This study contributes to the literature on the reliability of radiomics features with respect to MRI acquisition and the selection of reliable radiomics features for use in modeling in future HNC MRgRT applications.

GC-MS Analysis of Chemical Constituents of Volatile Oils of the Yao Medicine Thunbergia grandiflora from Different Habitats in Guangxi

[Objectives]This study was conducted to compare and analyze the chemical constituents of the volatile oils of the Yao medicine Thunbergia grandiflora from different habitats.[Methods]A quartz capillary column DB-1MS,an EI ion source and a quadrupole mass analyzer were used for analysis.The chromatographic and mass spectrum information obtained was automatically retrieved and analyzed by data processing system and its memory spectrum library(Nist.08).The relative content of each chemical component in the volatile oil was determined by the peak area normalization method.[Results]Forty nine chromatographic peaks were isolated from the sample produced in Shitun,Bailongtan Town,Mashan County,and 24 chemical constituents were identified,accounting for 88.78% of the total volatile oil.Forty nine chromatographic peaks were isolated from the sample produced in Hongdu Village,Chengjiang Town,Duan County,and 30 chemical constituents were identified,accounting for 88.38% of the total volatile oil.Forty eight chromatographic peaks were isolated from the sample produced in Longwan Township,Du'an County,and 25 chemical constituents were identified,accounting for 80.01% of the total volatile oil.Nine chemical constituents were common to the volatile oils of the samples from the three habitats.[Conclusions]It could be seen that the main components of volatile oils from T.grandiflora produced in different areas are different.