Identification of a fatty acid metabolism-related gene signature to predict prognosis in stomach adenocarcinoma.

BACKGROUND: Fatty acid metabolism (FAM) contributes to tumorigenesis and tumor development, but the role of FAM in the progression of stomach adenocarcinoma (STAD) has not been comprehensively clarified. METHODS: The expression data and clinical follow-up information were obtained from The Cancer Genome Atlas (TCGA). FAM pathway was analyzed by gene set enrichment analysis (GSEA) and single-sample GSEA (ssGSEA) methods. Univariate Cox regression analysis was conducted to select prognosis genes. Molecular subtypes were classified by consensus clustering analysis. Furthermore, least absolute shrinkage and selection operator (Lasso) analysis was employed to develop a risk model. ESTIMATE and tumour immune dysfunction and exclusion (TIDE) algorithm were used to assess immunity. pRRophetic package was conducted to predict drug sensitivity. RESULTS: Based on 14 FAM related prognosis genes (FAMRG), 2 clusters were determined. Patients in C2 showed a worse overall survival (OS). Furthermore, a 7-FAMRG risk model was established as an independent predictor for STAD, with a higher riskscore indicating an unfavorable OS. High riskscore patients had higher TIDE score and these patients were more sensitive to anticancer drugs such as Bortezomib, Dasatinib and Pazopanib. A nomogram based on riskscore was an effective prediction tool applicable to clinical settings. The results from pan-cancer analysis supported a prominent application value of riskscore model in other cancer types. CONCLUSION: The FAMRGs model established in this study could help predict STAD prognosis and offer new directions for future studies on dysfunctional FAM-induced damage and anti-tumor drugs in STAD disease.

The influence of simulated weightlessness on the composition and function of gut microbiota and bile acid metabolism products.

The aim of this study was to investigate the effects of simulated weightlessness on gut microbiota, bile acid metabolism, and inflammatory cytokines compared to the control group. The study compared the changes in gut microbiota at the phylum and genus levels in the feces of control and weightlessness rats after 1 and 8 weeks using fecal 16S rRNA sequencing. In the weightlessness group, there was an increase in the proportion of anaerobic bacteria and biofilm-forming bacteria, and a decrease in the proportion of aerobic and Gram-negative bacteria. Further investigations explored the impact of weightlessness on bile acid metabolism products. The levels of glycine ursodeoxycholic acid, glycine chenodeoxycholic acid, glycine deoxycholic acid and glycine cholic acid levels were lower in rats undergoing weightlessness for 1 week compared to the control group.Moreover, the study examined the relationship between gut microbiota and bile acid metabolism products.It was observed that, unlike the control group, there were significant positive correlations between Planctomycetes, Proteobacteria, Synergistetes, and GUDCA levels in rats after 1 week of weightlessness. Finally, ELISA results indicated significant differences in the levels of MDA, GSH, NLRP3, and SIgA inflammatory cytokines between rats undergoing weightlessness for 1 week and the control group rats. Our research confirmed that the simulated weightlessness environment significantly affects the gut microbiota and bile acid metabolism in rats, potentially leading to changes in inflammatory cytokines and causing intestinal tissue inflammation. Further exploring the relationship between gut microbiota and bile acid metabolism under weightless conditions will be crucial for understanding the functional changes in the intestines caused by weightlessness.

Harmonic and anharmonic studies on THz spectra of two vanillin polymorphs.

Polymorphism commonly exists in organic molecular crystals. The fingerprint features in low-frequency vibrational range are important information reflecting different intermolecular interactions of polymorphs. Interpreting these features is very helpful to understand vibrational property of polymorphs and reveal the thermodynamic stability. In this work, the low-frequency vibrations of form I and II of vanillin are investigated using terahertz time-domain spectroscopy. Static DFT calculation and ab initio molecular dynamics (AIMD) are employed to interpret their low-frequency vibrations of both forms in harmonic and anharmonic ways, respectively. Their low-frequency vibration characteristics in harmonic calculations are discussed, and anharmonic mode couplings between OH bond stretch and the stretching and bending motion of hydrogen bonds are uncovered. Moreover, the thermodynamic energies including electronic potential energy and vibrational/kinetic energy arising from nuclear motions are calculated. The result reveals that the stability order of the two forms is mainly dependent on their electric potential energy difference.

Left atrial function index predicts poor outcomes in acute myocardial infarction patients treated with percutaneous coronary intervention.

Background and aims: The left atrial function index (LAFI) is an index that combines the left atrial emptying fraction, adjusted left atrial volume and stroke volume. The prognostic value of LAFI in acute myocardial infarction (AMI) patients treated with percutaneous coronary intervention (PCI) is unknown. This study aims to determine whether LAFI predicts prognosis in AMI patients treated with PCI. Methods: Patients with newly diagnosed AMI who were treated with PCI at Hunan Provincial People's Hospital from March 2020 to October 2021 were prospectively enrolled. All patients underwent transthoracic echocardiography (TTE) at baseline and follow-up. The endpoint events included rehospitalization due to unstable angina, nonfatal myocardial infarction, rehospitalization due to heart failure and cardiovascular death. Results: A total of 368 patients with AMI (92 women; mean age, 61.45 ± 11.91 years) were studied with a median follow-up of 14 ± 6.58 months. Sixty-nine patients had endpoint events. Patients who presented with events had a significantly lower LAFI than patients without events (34.25 ± 12.86 vs. 48.38 ± 19.42, P < 0.0001). Multivariate Cox analysis demonstrated that LAFI (HR = 0.97 [95% CI: 0.95; 0.99]; P = 0.012) and the Killip classification (HR = 1.51 [95% CI: 1.03; 2.22]; P = 0.034) were independently predictive of endpoint events. Kaplan-Meier survival curves showed that patients with LAFI ≤ 40.17 cm/ml/m2 had higher events than patients with LAFI > 40.17 cm/ml/m2 (HR = 8.53 [95% CI: 4.74; 15.35]; P < 0.0001). Conclusion: LAFI is a strong and independent predictor of adverse events and can be used for risk stratification in patients with AMI treated with PCI.

A Comparison Between W Score and RYAN Score in Diagnosing Laryngopharyngeal Reflux Disease.

OBJECTIVE: To assess the diagnostic value of the W score in differentiating laryngopharyngeal reflux disease (LPRD) patients from the normal population by pharyngeal pH (Dx-pH) monitoring, compared with the RYAN score. METHODS: One hundred and eight patients with suspected LPRD and complete follow-up results after more than 8 weeks of anti-reflux therapy were enrolled from the Department of Otolaryngology-Head and Neck Surgery, Gastroenterology and Respiratory Medicine of seven hospitals. Their Dx-pH monitoring data before treatment were reanalyzed to obtain the W score in addition to the RYAN score and then the diagnostic sensitivity and specificity were compared and evaluated with reference to the result of anti-reflux therapy. RESULTS: In eighty-seven (80.6%) cases, anti-reflux therapy was effective, and in 21 patients (19.4%), therapy was ineffective. Twenty-seven patients (25.0%) had a positive RYAN score. The W score was positive in 79 (73.1%) patients. There were 52 patients who had a negative RYAN score, but a positive W score. The diagnostic sensitivity, specificity, positive predictive value, and negative predictive value of the RYAN score were 28.7%, 90.5%, 92.6%, and 23.5%, respectively (kappa = 0.092, P = 0.068), whereas those of the W score for LPRD was 83.9%, 71.4%, 92.4%, and 51.7%, respectively (kappa = 0.484, P < 0.001). CONCLUSIONS: W score is much more sensitive for the diagnosis of LPRD. Prospective studies with larger patient populations are necessary to validate and improve diagnostic efficacy. TRIAL REGISTRATION: Chinese Clinical Trial Registry: ChiCTR1800014931.

Left atrial function index predicts poor outcome in STEMI patients treated with percutaneous coronary intervention.

The prognostic value of the left atrial function index (LAFI) in acute ST segment elevation myocardial infarction (STEMI) patients treated with percutaneous coronary intervention (PCI) is unknown. This study sought to determine whether the LAFI predicts prognosis in STEMI patients treated with PCI. Patients with newly diagnosed STEMI who were treated with PCI in Hunan Provincial People's Hospital from March 2020 to October 2020 were prospectively enrolled. All patients underwent transthoracic echocardiography at baseline and follow-up. The endpoint events included rehospitalization due to unstable angina, nonfatal myocardial infarction, rehospitalization due to heart failure and cardiovascular death. A total of 156 STEMI patients treated with PCI were studied with a median follow-up of 14 months. Forty-eight patients had endpoint events. The LAFI had the highest area under the receiver operating characteristic curve (AUC) predicting the endpoint events, with an AUC of 0.90 (95% CI 0.84-0.94). Multivariate Cox analysis demonstrated that only the LAFI (HR: 0.91, 95% CI 0.87-0.96, P < 0.0001) was independently predictive of endpoint events. Kaplan‒Meier survival curves showed that patients with an LAFI ≤ 42.25 cm/cc/m2 had more events than patients with an LAFI > 42.25 cm/cc/m2 (HR: 19.15, 95% CI 8.90-41.21, P < 0.001). The LAFI is a strong and independent predictor of events in STEMI patients treated with PCI.

Ultrasound-guided fine-needle aspiration/biopsy-based pancreatic organoids establishment: an alternative model for basic and preclinical research.

Pancreatic ductal adenocarcinoma (PDAC), as one of the malignant cancers with the worst prognosis, is becoming the most urgent clinical problem. Due to the lack of early diagnosis and curable therapeutic methods, it is critical to exploit proper models that can capture the overall attributes of the primary tumor. Recently, organoid technology has emerged and flourished as a powerful tool to enable long-term culture of pancreatic tissues, including PDAC. As accumulating studies suggest, organoids can retain morphological, genetic, and behavioral traits, and have tremendous value in predicting the therapeutic response to conventional chemotherapy drugs or newfangled agents. Herein, this review comprehensively summarizes the tissue source including human fetal and adult pancreatic tissue to generate a pancreatic organoid as well as current organoids cultivate system. As PDAC organoids can be established from a small number of samples derived from endoscopic ultrasound-guided fine-needle aspiration/biopsy (EUS-FNA/FNB), we also review the literature to date on EUS-FNA/FNB-based organoid constitution and its implementation in inquiring tumor behavior and evaluating therapeutic responses. By enabling the alignment of basic and clinical research platforms, the application of organoids would open up new avenues for drug discovery and maximally benefit translational medicine in the near future.

Identification of m6A regulator-mediated RNA methylation modification patterns and key immune-related genes involved in atrial fibrillation.

The role of m6A in the regulation of the immune microenvironment in atrial fibrillation (AF) remains unclear. This study systematically evaluated the RNA modification patterns mediated by differential m6A regulators in 62 AF samples, identified the pattern of immune cell infiltration in AF and identified several immune-related genes associated with AF. A total of six key differential m6A regulators between healthy subjects and AF patients were identified by the random forest classifier. Three distinct RNA modification patterns (m6A cluster-A, -B and -C) among AF samples were identified based on the expression of 6 key m6A regulators. Differential infiltrating immune cells and HALLMARKS signaling pathways between normal and AF samples as well as among samples with three distinct m6A modification patterns were identified. A total of 16 overlapping key genes were identified by weighted gene coexpression network analysis (WGCNA) combined with two machine learning methods. The expression levels of the NCF2 and HCST genes were different between controls and AF patient samples as well as among samples with the distinct m6A modification patterns. RT-qPCR also proved that the expression of NCF2 and HCST was significantly increased in AF patients compared with control participants. These results suggested that m6A modification plays a key role in the complexity and diversity of the immune microenvironment of AF. Immunotyping of patients with AF will help to develop more accurate immunotherapy strategies for those with a significant immune response. The NCF2 and HCST genes may be novel biomarkers for the accurate diagnosis and immunotherapy of AF.

Clinical efficacy of endoscopic antireflux mucosectomy vs. Stretta radiofrequency in the treatment of gastroesophageal reflux disease: a retrospective, single-center cohort study.

Background: Currently, antireflux mucosectomy (ARMS) and Stretta radiofrequency (SRF) are the most commonly used minimally invasive antireflux therapies. To date, there have not been any reports comparing ARMS and SRF. Our aim was to compare the clinical efficacies of these two therapeutic methods. Methods: We analyzed data from gastroesophageal reflux disease (GERD) patients, including 39 who received ARMS treatment and 30 who received SRF treatment between January 2020 and May 2021. Symptom control, gastroesophageal reflux disease questionnaire (GERDQ) score, gastroesophageal reflux disease health-related quality of life (GERD-HRQL) score, proton pump inhibitor (PPI) withdrawal, and PPI reduction were analyzed and compared. Results: After 6 months of follow-up, the results showed that both therapies were effective in improving symptoms and quality of life. No difference was found between the ARMS group and SRF group in GERDQ score, GERD-HRQL score, PPI withdrawal rate, or PPI reduction rate (P>0.05). There was no significant difference in the PPI withdrawal rate between the two therapies among patients with gastroesophageal flap valve (GEFV) grade II and grade III (P>0.05), but the PPI withdrawal rate in the ARMS group was significantly higher than that in the SRF group among patients with GEFV grade IV (P<0.05). Conclusions: The clinical efficacies of ARMS and SRF 6 months postoperation were equivalent. The results showed that both ARMS and SRF treatment were acceptable for patients with GEFV grades II and III, while ARMS should be selected for patients with GEFV grade IV.

Regulation of Cholesterol Binding to the Receptor Patched1 by its interactions With the Ligand Sonic Hedgehog (Shh).

The Hedgehog (Hh) signaling pathway is essential in cell development and regeneration, which is activated by the ligand Sonic hedgehog (Shh). The binding of Shh to its receptor Patched1 (PTCH1) releases the inhibitory effect on the downstream protein Smoothened (SMO), a G-protein-coupled-receptor (GPCR) protein. Cholesterol was supposed to function as a secondary messenger between PTCH1 and SMO. However, the molecular mechanism of this regulation process is still unclear. Therefore, microsecond coarse-grained molecular dynamics simulations were performed to investigate the protein-lipid interactions of the PTCH1 monomer and dimer-Shh complex. It was observed that the binding of cholesterols to the monomer is more stable than that to the dimer-Shh complex. It is regulated by the enrichment of Ganglioside lipids around proteins and the conformation of Y446, a residue in the sterol-sensing domain (SSD). The regulation of Shh on the dynamics of PTCH1 was further analyzed to explore the allosteric communication pathways between the Shh and the SSD. Our study provides structural and dynamic details of an additional perspective on the regulation of Hh signaling pathway through the lipid micro-environments of PTCH1.

Supramolecular Organization of SARS-CoV and SARS-CoV-2 Virions Revealed by Coarse-Grained Models of Intact Virus Envelopes.

The coronavirus disease 19 (COVID-19) pandemic is causing a global health crisis and has already caused a devastating societal and economic burden. The pathogen, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has a high sequence and architecture identity with SARS-CoV, but far more people have been infected by SARS-CoV-2. Here, combining the structural data from cryo-electron microscopy and structure prediction, we constructed bottom-up Martini coarse-grained models of intact SARS-CoV and SARS-CoV-2 envelopes. Microsecond molecular dynamics simulations were performed, allowing us to explore their dynamics and supramolecular organization. Both SARS-CoV and SARS-CoV-2 envelopes present a spherical morphology, with structural proteins forming multiple string-like islands in the membrane and clusters between the heads of spike proteins. Critical differences between the SARS-CoV and SARS-CoV-2 envelopes are the interaction pattern between the spike proteins and the flexibility of the spike proteins. Our models provide structural and dynamic insights into the SARS virus envelopes and could be used for further investigation, such as drug design and membrane fusion and fission processes.

Gastroesophageal reflux disease: recent innovations in endoscopic assessment and treatment.

Innovations in endoscopy have brought about some impressive improvements in diagnosing and treating gastroesophageal reflux disease (GERD). GERD, as one of the most prevalent gastrointestinal disorders in the world, has always been on the cutting edge of endoscopic interventions. A primary diagnosis of GERD is based on symptoms and an initial trial of proton-pump inhibitor (PPI) therapy, which is devoid of adequately instructive value for therapeutic strategies. Endoscopy and optional biopsies can be used to directly observe and determine the abnormal structural and pathophysiological damage in the esophagus. The emergence of minimally invasive endoscopic therapy fills the gap between patients who are reluctant or insensitive to PPIs and candidates who are not indicated for surgical anti-reflux fundoplication. In this review, we discuss the utility of endoscopy and biopsy in patients with persistent GERD-related manifestations after proper medical anti-reflux treatment. Moreover, we portray a landscape of four current endoscopic GERD therapies and clarify the merits and disadvantages of each technique. Future research needs to concentrate on stratifying GERD patients based on personal conditions and elucidating the primary pathophysiology of GERD.

Application of the improved simple bedside method for emergency temporary pacemaker implantation suitable for primary hospitals.

The purpose of the research was to evaluate the safety and effectiveness of the X-ray-free improved simple bedside method for emergency temporary pacemaker implantation as well as the practicability of the method in primary hospitals. Patients [including those suffering from sick sinus syndrome and third-degree and advanced atrioventricular blockage (AVB)] who needed emergency temporary pacemaker implantation from July 2017 to August 2020 in Hunan Provincial People's Hospital were selected. They were stochastically divided into a research group (95 cases) treated with the improved simple bedside method and a control group (95 cases) with X-ray guidance. The ordinary bipolar electrodes were used in both groups. On this condition, the operation duration, the first-attempt success rate of electrodes, pacing threshold, success rate of the operation, the rate of electrode displacement, and complications in the two groups were separately calculated. The comparison results of the research group with the control group are shown as follows: operation time [(18 ± 5.91) min vs. (43 ± 2.99) min, P < 0.05], the first-attempt success rate of the electrode (97% vs. 98%, P > 0.05), pacing threshold [(0.97 ± 0.35) vs. (0.97 ± 0.32) V, P > 0.05], success rate of the operation (98.9% vs. 100%, P > 0.05), the rate of electrode displacement (8.4% vs. 7.3%, P > 0.05) and complications (3.2% vs. 2.1%, P > 0.05). The emergency temporary pacemaker implantation based on the improved simple bedside method is as safe and effective as the surgical method under X-ray guidance, and the operation is simpler and easier to learn and requires a shorter operating time, therefore, it is more suitable for use in emergency and primary hospitals.

The relationship between KRAS gene mutation and intestinal flora in tumor tissues of colorectal cancer patients.

BACKGROUND: Colorectal cancer is among the most prominent malignant tumors endangering human health, with affected populations exhibiting an increasingly younger trend. The Kirsten ras (KRAS) gene acts as a crucial regulator in this disease and influences multiple signaling pathways. In the present study, the KRAS gene mutation-induced alteration of intestinal flora in colorectal cancer patients was explored, and the intestinal microbes that may be affected by the KRAS gene were examined to provide new insights into the diagnosis and treatment of colorectal cancer. METHODS: Deoxyribonucleic acid (DNA) was extracted from 177 colorectal cancer patients in our hospital. The mutation of the KRAS gene was subsequently detected using real-time fluorescence quantitative polymerase chain reaction (qPCR), and survival analysis was performed. Moreover, genomic DNA was extracted from the fecal microbes in 30 of these patients, and the differences in the intestinal flora between mutation and non-mutation groups were evaluated using linear discriminant analysis (LDA) Effect size (LEfSe) analysis. RESULTS: KRAS gene mutation substantially affected the distant metastasis of colorectal cancer, and the survival prognosis in the non-mutation group was significantly superior compared to the mutation group. The mutation group had a notably higher prevalence of microbes including Roseburia, Parabacteroides, Metascardovia, Staphylococcus, Staphylococcaceae, and Bacillales than the non-mutation group. The presence of microbes in the non-mutation group, such as Clostridiales, Bacteroidetes, Lachnospiraceae, Coprococcus, and Ruminococcaceae was markedly higher than in the mutation group. Firmicutes were negatively correlated with the presence of Actinomyces and Bacteroidetes, while Bacteroidetes were positively associated with the level of Actinomyces. CONCLUSIONS: In colorectal cancer, KRAS gene mutation can remarkably affect the survival prognosis and change the composition and abundance of intestinal flora, such as Roseburia, Parabacteroides, Metascardovia, Staphylococcus, and Bacillales, thereby influencing tumor development.

Relationship between reflux diseases and obstructive sleep apnea together with continuous positive airway pressure treatment efficiency analysis.

BACKGROUND: Obstructive sleep apnea (OSA) is known to be highly associated with reflux diseases. There is evidence that continuous positive airway pressure (CPAP) can decrease the clinical symptoms of gastroesophageal reflux (GER) in OSA patients, but whether CPAP can decrease nocturnal laryngopharyngeal reflux (LPR) episodes is still lack of strong evidence. OBJECTIVE: To investigate the efficiency of CPAP on LPR and the relationship between LPR, GER and OSA. STUDY DESIGN: retrospective study. METHODS: Forty adult patients who had confirmed OSA by polysomnography and suspected LPR were enrolled. Their results of synchronous polysomnography and 24 h esophageal and oropharyngeal Dx-pH monitoring were analyzed. Twenty-seven OSA patients were treated with CPAP on the second night. The nocturnal reflux parameters with and without CPAP treatment were compared. RESULTS: 15.0% and 42.5% of OSA patients were associated with LPR and GER through Dx-pH monitoring respectively. Nevertheless, more than one reflux attack falling below pH6.0 of oropharynx during sleep time was detected in 80.0% patients. There was a significant inverse correlation between the lowest/mean pH values of oropharynx and obstructive apnea index (OAI), so was the lowest pH values of esophagus. Significant positive correlation was calculated between the total number of reflux episodes below pH6.0 of oropharynx and apnea-hypopnea index (AHI)/OAI/hypopnea index (HI). A similar positive correlation was also significant between AHI/OAI and GER parameters. The assessment of the efficacy of CPAP treatment showed significant difference both in GER and LPR related parameter. CONCLUSIONS: OSA patients have a higher incidence of nocturnal LPR and GER. CPAP treatment can effectively reduce both GER and LPR attacks while disordered sleep events reduced in OSA patients.

Reflux finding score is associated with gastroesophageal flap valve status in patients with laryngopharyngeal reflux disease: a retrospective study.

Endoscopic grading of gastroesophageal flap valve (GEFV) is simple and reproducible and offers useful information for reflux activity. To investigate the potential correlation between GEFV grading and reflux finding score (RFS) in patients with laryngopharyngeal reflux disease (LPRD), 225 consecutive Patients with suspected LPRD who underwent both routine upper gastrointestinal endoscopy and laryngoscope were enrolled in our study. Patients with a RFS of more than 7 were diagnosed with LPRD. The GEFV was graded as I through IV according to Hill's classification and was classified into two groups: normal GEFV group (grades I and II) and the abnormal GEFV group (grades III and IV). The percent of GEFV grades I to IV was 39.1%, 39.1%, 12.4%, and 9.3%, respectively. Age was significantly related to an abnormal GEFV (p = 0.002). Gender, BMI, smoke and alcohol were not related to GEFV grade. Fifty-one patients (22.67%) had positive RFS. Reflux finding scores were higher in GEFV grades III and IV than I and II (p < 0.05). Endoscopic grading of GEFV is well correlated with reflux finding score in patients with LPRD. This is a simple and useful technique that provides valuable diagnostic information of LPRD.

Factors influencing the attention to home storage of medicines in China.

BACKGROUND: Medicines are stored in most households around the world for a range of different purposes including emergency use and the treatment of acute or chronic illnesses. The presence of medicines in households is becoming a significant risk factor for irrational medicine storage, disposal, and use in developing countries due to limited information and knowledge offered on safe storage. This study examined how patients store medicines and highlighted factors which influence home storage behaviours for medicines in China. METHOD: A cross-sectional survey of 625 households was undertaken. In each household, data were collected from the head of household present at home. The study covered six provinces in China including the North, Central, and Southern regions. Respondents were interviewed by doctors. The doctors were study assistants and data collectors. "Attention" was taken as the research focus and a five-point Likert scale was used to measure attitudes to medicine storage at home. Factor analysis, variance analysis, and the multivariable logistic regression models were employed in the present study. RESULTS: Of the households investigated in this study, cold medications were the medicine most commonly stored at home. The majority of the respondents gave more attention to the expiration date of medicines compared to other factors. Only a few respondents thought humidity was important factor influencing home storage of medicines. Despite some attention being given to the location of storage for home medicines, considerably more information is needed to improve awareness. In addition, our data revealed that some attention had been paid to elimination and recycling mechanisms but similarly, increased awareness is needed. There were obvious differences between the populations used in the study, due to differences in socio-demographic characteristics of the study participants. Age is the most important factor influencing the attention paid to home storage of medicines in China. CONCLUSION: A major improvement in the awareness of correct storage conditions of medicines for home use can be realized by increased education, and highlighting the importance of correct medicine storage, disposal methods and usages, which has high potential to deliver public health benefits in China. Some suggestions were provided to health care providers.

Estrogen inhibits the overgrowth of Escherichia coli in the rat intestine under simulated microgravity.

Microgravity can affect many aspects of intestinal homeostasis, leading to an increased risk of colitis. Estrogen, the most frequently affected hormone when under simulated microgravity, regulates the permeability of the colonic mucosa barrier. The associations between alterations in intestinal microbiota and increased susceptibility under microgravity have not been thoroughly elucidated. The aim of the present study was to evaluate the changes in intestinal microbiota under simulated microgravity and to investigate the protective effect of estrogen against those changes. The hindlimb unweighting (HU) model was used to simulate microgravity in rats. Estrogen was administered via intramuscular injection. Amplicons of the V3 variable regions of bacterial 16S rDNA were analyzed using denaturing gradient gel electrophoresis (DGGE), cloning and sequencing. Several specific bacterial groups were assayed using quantitative­polymerase chain reaction. Bacterial translocation was evaluated by detecting serum lipopolysaccharide (LPS) and LPS binding protein (LBP) levels. DGGE profiles generated by universal primers revealed minor, though specific, changes in bacterial communities under simulated microgravity, particularly the band matching the sequence of Escherichia coli (E. coli). The quantification of 16S RNA revealed increased numbers of Bacteroides fragilis, E. coli and Fusobacterium nucleatum; however, Bifidobacteria longum significantly decreased under microgravity. Estrogen inhibited the overgrowth of E. coli, and decreased the levels of LBS and LBP under simulated microgravity. These results demonstrated that simulated microgravity alters the intestinal microflora and may contribute to bacterial translocation in the gut mucosa. The data also suggested that further investigations evaluating the administration of estrogen to protect against microgravity­associated diseases may be required.