miR-25 Mediates Retinal Degeneration Via Inhibiting ITGAV and PEDF in Rat

BACKGROUND

Age-related macular degeneration (AMD) is the main cause of irreversible blindness in the elderly. Oxidative stress in retinal pigment epithelium (RPE) is deemed to play a pivotal role in the pathogenesis of AMD. miR-25 functions as an essential modulator in response to oxidative-stress in several cell types, but its function in RPE cells is poorly understood.

OBJECTIVE

To explore the roles of miR-25 in RPE cells and in the development of AMD.

METHODS

A rat model of retinal degeneration was induced by sodium iodate (SI). Subretinal injection of antagomiR-25 was performed for the intervention while the scramble as control. Visual responses were recorded with Electroretinogram (ERG). TUNEL assay was performed to detect apoptosis. Phagosome quantification in vivo was performed to evaluate RPE cell function. Oxygen-glucose deprivation treatment was performed to mimic in vitro oxidative stress. Gene expression at mRNA level and protein level were performed by quantitative polymerase chain reaction (qPCR) and Western Blot, respectively. The pigment epithelium derived factor (PEDF) level in the cultured medium was measured by Enzyme-linked immunosorbent assay (ELISA). The interaction between miR-25 and integrin αV (IGTAV) / PEDF 3'UTR was examined by dual luciferase assay. Chromatin immunoprecipitation (ChIP) assay was performed to examine its transcriptional regulation of miR-25.

RESULTS

Oxidative stress up-regulated miR-25 in RPE cells in very early stage, accompanied by decreased phagocytosis and reduced growth factor secretion in those cells. Such changes preceded RPE cell apoptosis and visual impairment in the SItreated rats. Furthermore, antagomiR-25 intervention effectively rescued RPE cells from degeneration in such model. The increased miR-25 was confirmed to mediate RPE degeneration through direct targeting IGTAV and PEDF. On the other hand, upstream, miR-25 was found to be up-regulated by STAT3 signaling under oxidative stress in both in vivo and in vitro models.

CONCLUSION

Our findings demonstrate that, in SI-treated rats, oxidative stress activates STAT3 signaling which up-regulates miR-25 expression, in a very early stage. The increased miR-25 then inhibits ITGAV and PEDF expressions, resulting in RPE phagocytosis dysfunction and then RPE apoptosis and visual impairment as observed in patients with AMD. These findings lead us to a better understanding of AMD pathogenesis, and suggest that miR-25 could be a potential therapeutic target for oxidative stress related RPE diseases, like AMD.

Epidemiology of paediatric gastrointestinal colonisation by extended spectrum cephalosporin-resistant Escherichia coli and Klebsiella pneumoniae isolates in north-west Cambodia

Background

Extended-spectrum cephalosporin resistance (ESC-R) in Escherichia coli and Klebsiella pneumoniae is a healthcare threat; high gastrointestinal carriage rates are reported from South-east Asia. Colonisation prevalence data in Cambodia are lacking. The aim of this study was to determine gastrointestinal colonisation prevalence of ESC-resistant E. coli (ESC-R-EC) and K. pneumoniae (ESC-R-KP) in Cambodian children/adolescents and associated socio-demographic risk factors; and to characterise relevant resistance genes, their genetic contexts, and the genetic relatedness of ESC-R strains using whole genome sequencing (WGS).

Results

Faeces and questionnaire data were obtained from individuals < 16 years in north-western Cambodia, 2012. WGS of cultured ESC-R-EC/KP was performed (Illumina). Maximum likelihood phylogenies were used to characterise relatedness of isolates; ESC-R-associated resistance genes and their genetic contexts were identified from de novo assemblies using BLASTn and automated/manual annotation. 82/148 (55%) of children/adolescents were ESC-R-EC/KP colonised; 12/148 (8%) were co-colonised with both species. Independent risk factors for colonisation were hospitalisation (OR: 3.12, 95% CI [1.52–6.38]) and intestinal parasites (OR: 3.11 [1.29–7.51]); school attendance conferred decreased risk (OR: 0.44 [0.21–0.92]. ESC-R strains were diverse; the commonest ESC-R mechanisms were bla_CTX-M 1 and 9 sub-family variants. Structures flanking these genes were highly variable, and for bla_{CTX-M-15, − 55 and − 27} frequently involved IS26. Chromosomal bla_CTX-M integration was common in E. coli.

Conclusions

Gastrointestinal ESC-R-EC/KP colonisation is widespread in Cambodian children/adolescents; hospital admission and intestinal parasites are independent risk factors. The genetic contexts of bla_CTX-M are highly mosaic, consistent with rapid horizontal exchange. Chromosomal integration of bla_CTX-M may result in stable propagation in these community-associated pathogens.

Electronic supplementary material

The online version of this article (10.1186/s12866-019-1431-9) contains supplementary material, which is available to authorized users.

Imaging features of combined hepatocellular and cholangiocarcinoma compared with those of hepatocellular carcinoma and intrahepatic cholangiocellular carcinoma in a Chinese population

AIM

To determine the enhanced computed tomography (CT) and magnetic resonance imaging (MRI) characteristics of combined hepatocellular carcinoma and cholangiocarcinoma (cHCC-CC) in Chinese patients.

MATERIALS AND METHODS

Patients with histopathologically proven cHCC-CC (n=54) were compared with hepatocellular carcinoma (HCC; n=41) and cholangiocellular carcinoma (CCC; n=41) patients. Clinical information was measured in all patients. Tumour size, tumour margins, signs of cirrhosis, pseudocapsule, capsular retraction, rim enhancement, intrahepatic biliary dilatation, portal vein thrombosis, upper abdominal lymphadenopathy, were assessed on CT and/or MRI. The dynamic pattern of enhancement was also assessed.

RESULTS

The majority (81.5%) of cHCC-CC patients had positive hepatitis B serology. The presence of cirrhosis and tumour blood vessels was comparable in cHCC-CC and HCC, but significantly lower in CCC (p>0.05). The presence of ill-defined margin and regional lymphadenopathy was comparable in cHCC-CC and CCC, but significantly lower in HCC (p>0.05). The pseudocapsule, capsular retraction, biliary dilatation, rim enhancement, and abnormal perfusion were significantly different between the three types of lesions, with cHCC-CC being intermediate between HCC and CCC. Nearly half of the cHCC-CC tumours (25; 46.3%) showed the wash-in and wash-out enhancement pattern; the gradual, persistent, and mixed patterns were seen in 12 (22.2%), 5 (9.3%), and 12 (22.2%) tumours, respectively.

CONCLUSION

The majority of cHCC-CC tumours occur against a background of positive hepatitis B serology and cirrhosis. Imaging findings vary widely between cHCC-CC tumours. In the present series, the enhancement pattern of cHCC-CC tumours was HCC-like in most cases.

Association between Ca/Mg/P status and suppurative tonsillitis in children

Suppurative tonsillitis (ST) is a common respiratory disease in children. This study aims to investigate the association between calcium (Ca)/magnesium (Mg)/phosphorus (P) and the risk of onset of suppuration in tonsillitis in children. Seventy children with ST and 61 age- and sex-matched children with non-ST were enrolled in this study. The association between Ca/Mg/P and suppuration risk in tonsillitis was investigated. The relationship between Ca/Mg/P and the potential risk factors for ST were also studied. White blood cell (WBC), platelet (PLT), c-reactive protein (CRP) and erythrocyte sedimentation rate (ESR) levels were significantly higher in the ST group than those in the non-ST group (p less than 0.05). Mg and P levels were significantly lower in the ST group than those in the non-ST group (p less than 0.05). There was no obvious difference in Ca level between the ST group and the non-ST group (p=0.762). A significantly negative association between P and PCT was noted (r=-0.236, p=0.035). The results indicated that Mg/P disorder may be associated with the susceptibility to suppuration in children with tonsillitis, inflammatory indexes may reflect this risk.

Intraruminal infusion of oligofructose alters ruminal microbiota and induces acute laminitis in sheep

The objectives of this study were to examine the clinical response, changes in ruminal bacterial microbiota, and inflammatory response in lamellar tissues during oligofructose-induced laminitis. Ten fistulated sheep were randomly assigned into a control group ( = 5) and a treatment group ( = 5). The treatment group was infused with oligofructose (21 g/kg BW) by rumen cannula, and the control group was sham-treated with saline. Results showed that all 5 sheep treated with oligofructose developed anorexia and diarrhea 8 to 12 h after the administration of oligofructose. By 12 to 24 h after treatment, the treatment group developed lameness and roach back. Compared with the control group, oligofructose administration decreased ( < 0.001) the rumen pH and concentrations of total VFA and increased ( < 0.001) the level of lactic acid in the rumen. Microbial data analysis revealed that oligofructose infusion increased the abundance of ( = 0.009) and ( = 0.008) and decreased the percentage of unclassified Christensenellaceae ( = 0.028), unclassified Ruminococcaceae ( = 0.009), ( = 0.016), unclassified Lachnospiraceae ( = 0.009), and ( = 0.009) compared with the control group. Oligofructose infusion decreased the ACE ( = 0.047) and Shannon ( = 0.009) indices compared with the control group. The histomorphology analysis revealed that oligofructose overload resulted in damage to the dermoepidermal junction in the lamellar tissue of sheep. Quantitative real-time PCR results showed that compared with the control group, the mRNA expression of membrane-type metalloproteinase-1 ( = 0.049) was downregulated whereas the expression of proinflammatory IL-6 ( = 0.004) and matrix metalloprotease-9 ( = 0.037) was upregulated in the lamellar tissues of the oligofructose treatment group. In general, the present study provides the foundation for a sheep model of oligofructose-overload-induced acute laminitis that could be used in later experiments. Our findings suggest that intraruminal infusion of oligofructose altered ruminal microbiota and resulted in acute laminitis and that the inflammatory damage to the lamellae tissue may be related to the upregulation of matrix metalloprotease-9. The information generated will provide more insight into the systemic effects of lameness caused by oligofructose overload in sheep.

Starter feeding altered ruminal epithelial bacterial communities and some key immune-related genes' expression before weaning in lambs

To characterize changes in ruminal epithelial bacterial communities and immune-related gene expression during concentrate starter feeding before weaning in lambs, 6 pairs of 10-d-old Hu lamb twins were selected: 1 kid received milk (M, = 6), and the other received milk plus starter (M+S, = 6). All lambs received hay and water ad libitum and were slaughtered at 56-d-old. Their rumen fluid was collected to determine ruminal pH and VFA levels; rumen epithelia were collected to characterize their bacterial communities using Illumina MiSeq sequencing and to determine mRNA expression of immune-related genes using quantitative real-time PCR (qRT-PCR). Results showed that starter feeding caused a decreased ruminal pH ( = 0.004) and increased concentrations of acetate, propionate, butyrate, and total VFA ( < 0.001). Principal coordinate analysis and analysis of molecular variance revealed that starter feeding affected ruminal epithelial bacterial communities in the lambs ( = 0.001), with higher relative abundance of dominant taxa , unclassified BS11 gut group, , unclassified Synergistaceae, , , , , and ( < 0.05) but lesser relative abundance of , unclassified Bacteroidales, unclassified Candidate, unclassified RF9, and ( < 0.05). Additionally, a phylogenetic investigation of communities by reconstruction of unobserved states analysis indicated that starter feeding markedly increased relative abundance values of dominant ruminal epithelial bacterial-inferred genes related to other ion-coupled transporters, pentose and glucuronate interconversions, glycosyltransferases, other glycan degradation, AA metabolism, sphingolipid metabolism, biotin metabolism, glycosphingolipid biosynthesis-globo series, and lysosome ( < 0.05) but decreased relative abundance values of genes related to carbon fixation pathways in prokaryotes and energy metabolism ( < 0.05) in the lambs. The qRT-PCR results showed that starter feeding decreased the relative mRNA expression of IL-6 ( = 0.003), IL-10 ( = 0.013), and interferon γ ( = 0.003). Collectively, this study showed that starter feeding could alter ruminal epithelial bacterial communities and some key immune-related genes' expression in preweaned lambs. All these responses of ruminal epithelial bacteria and the immune system would be beneficial for starter-fed lambs to be weaned.

[Expression and regulation of CD36 mRNA in granulosa cells and its relation with clinical characteristics of polycystic ovary syndrome]

OBJECTIVE

To study the expression of CD36 mRNA in granulosa cells (GCs) of patients with polycystic ovary syndrome (PCOS) and the impact of testosterone, insulin and PPARγ agonist rosiglitazone on GCs.

METHODS

The expression of CD36 mRNA inGCs of patients with PCOS and normal controls were assayed byreal-time PCR.The level of CD36 mRNA after treatment with testosterone, insulin, and rosiglitazone in GCs ofnormal controls were also tested by real-time PCR.

RESULTS

(1) The expression of CD36mRNA in the GCs of PCOS was significantly higher than that of the controls (P<0.05). (2) When testosterone concentration was 1 nmol/L, CD36 mRNA increased in the GCs, but there was no significantdifference compared to the blank control, (P>0.05). When testosterone concentration was 10 nmol/L, the expression of CD36 mRNA in the GCs was higher than that in the blank control with significant difference (P<0.05). When insulin concentration was 10 nmol/L, the expression of CD36 mRNA increased but the difference was not statistically significant (P>0.05). When insulin concentration was 100 nmol/L, the expression of CD36mRNA in the GCswas higher than that in the blank control (P=0.05). When rosiglitazone concentration was 1nmol/L, the expression of PPARγ mRNA in GCs were significantly increased compared with the blank control (P<0.05). The expression of CD36 mRNA atrosiglitazone concentrationof 10 nmol/Lwere significantly increased compared to the concentration of 1 nmol/L (P<0.05).

CONCLUSION

High testosterone and insulin induced the expression of CD36 mRNA.Rosiglitazone increased CD36 mRNA in a dose-related manner in GCs.Increased CD36 mRNA in the GCs of PCOS may be related to the clinical characteristics of PCOS.

Spectroscopic observation of nitrogen anions N(-) in solid matrices

Analysis of old and recent experiments on thermoluminescence of cryocrystals and nanoclusters of N2, Ne, Ar, and Kr containing stabilized nitrogen atoms, suggests that the so-called γ-line may correspond to the bound-bound transition (1)D-(3)P of nitrogen anions N(-) formed in solids by the association of delocalized electrons and metastable nitrogen atoms N((2)D). The recent observations of the γ-line were accompanied by simultaneous luminescence of metastable nitrogen N((2)D) atoms and exoelectron emission. The fine structure of the γ-line at 793 nm has been experimentally observed and investigated for the first time.

Assessing vascular effects of adding bevacizumab to neoadjuvant chemotherapy in osteosarcoma using DCE-MRI

BACKGROUND

The purpose of this study was to assess the impact of bevacizumab alone and in combination with cytotoxic therapy on tumour vasculature in osteosarcoma (OS) using DCE-MRI.

METHODS

Six DCE-MRI and three (18)F-FDG PET examinations were scheduled in 42 subjects with newly diagnosed OS to monitor the response to antiangiogenic therapy alone and in combination with cytotoxic therapy before definitive surgery (week 10). Serial DCE-MRI parameters (K(trans), v(p), and v(e)) were examined for correlation with FDG-PET (SUV(max)) and association with drug exposure, and evaluated with clinical outcome.

RESULTS

K(trans) (P=0.041) and v(p) (P=0.001) significantly dropped from baseline at 24 h after the first dose of bevacizumab alone, but returned to baseline by 72 h. Greater exposure to bevacizumab was correlated with larger decreases in v(p) at day 5 (P=0.04) and week 10 (P=0.02). A lower K(trans) at week 10 was associated with greater percent necrosis (P=0.024) and longer event-free survival (P=0.034).

CONCLUSIONS

This is the first study to demonstrate significant changes of the plasma volume fraction and vascular leakage in OS with bevacizumab alone. The combination of demonstrated associations between drug exposure and imaging metrics, and imaging metrics and patient survival during neoadjuvant therapy, provides a compelling rationale for larger studies using DCE-MRI to assess vascular effects of therapy in OS.

Dynamic nuclear polarization of high-density atomic hydrogen in solid mixtures of molecular hydrogen isotopes

We report on magnetic resonance studies of high-density atomic hydrogen and deuterium in solid hydrogen matrices at temperatures below 1 K. Average concentrations of H atoms ≈3×10(19)  cm(-3) are obtained in chemical tunneling reactions of isotope exchange with D atoms. The products of these reactions are closely located pairs of H atoms near D2 molecules with strong exchange interactions. We discovered a dynamic nuclear polarization effect on H atoms created by pumping the center of the H electron spin resonance spectrum, similar to the Overhauser effect in metals. Our results indicate that H atoms may be arranged inside molecular matrices at separations equivalent to local concentrations of 2.6×10(21)  cm(-3). This opens up a way to build a metallic state of atomic hydrogen at zero pressure.

Experimental setup for investigation of nanoclusters at cryogenic temperatures by electron spin resonance and optical spectroscopies

We present the design and performance of an experimental setup for simultaneous electron spin resonance (ESR) and optical studies of nanoclusters with stabilized free radicals at cryogenic temperatures. A gas mixture of impurities and helium after passing through a RF discharge for dissociation of molecules is directed onto the surface of superfluid helium to form the nanoclusters of impurities. A specially designed ESR cavity operated in the TE011 mode allows optical access to the sample. The cavity is incorporated into a homemade insert which is placed inside a variable temperature insert of a Janis (4)He cryostat. The temperature range for sample investigation is 1.25-300 K. A Bruker EPR 300E and Andor 500i optical spectrograph incorporated with a Newton EMCCD camera are used for ESR and optical registration, respectively. The current experimental system makes it possible to study the ESR and optical spectra of impurity-helium condensates simultaneously. The setup allows a broad range of research at low temperatures including optically detected magnetic resonance, studies of chemical processes of the active species produced by photolysis in solid matrices, and investigations of nanoclusters produced by laser ablation in superfluid helium.

Experimental cell for molecular beam deposition and magnetic resonance studies of matrix isolated radicals at temperatures below 1 K

We present the design and performance of an experimental cell constructed for matrix isolation studies of H and D atoms in solid H2/D2 films, which are created by molecular beam deposition at temperatures below 1 K. The sample cell allows sensitive weighing of the films by a quartz microbalance (QM) and their studies by magnetic resonance techniques in a strong magnetic field of 4.6 T. We are able to regulate the deposition rate in the range from 0.01 to 10 molecular layers/s, and measure the thickness with ≈0.2 monolayer resolution. The upper QM electrode serves as a mirror for a 128 GHz Fabry-Perot resonator connected to an electron spin resonance (ESR) spectrometer. H and D atoms were created by RF discharge in situ in the sample cell, and characterized by ESR and electron-nuclear double resonance. From the magnetic resonance measurements we conclude that the films are smooth and provide homogeneous trapping conditions for embedded atoms. The current sample cell design also makes it possible to calibrate the ESR signal and estimate the average and local concentrations of H and D radicals in the film.

Luminescence of oxygen atoms stimulated by metastable helium at cryogenic temperatures

We present investigations of the afterglow of oxygen-helium gas mixtures at cryogenic temperatures. The cooling of a helium jet containing trace amounts of oxygen after passing through a radio frequency discharge zone led to the observation of strong emissions from atomic oxygen. The effect results from the increasing efficiency of energy transfer from metastable helium atoms and molecules to oxygen impurities in the cold dense helium vapor. This effect might find an application for the detection of small quantities of the impurities in helium gas.