Probing electron transfer between hemin and riboflavin using a combination of analytical approaches and theoretical calculations.

Extracellular electron transfer (EET) occurs from outer-membrane proteins to electron acceptors. Heme(ii) is the active center of outer-membrane proteins and delivers electrons to acceptors or mediators such as riboflavin, a redox active chromophore present in organisms. However, the EET mechanism via mediators, especially the electron transfer process from outer-membrane proteins to mediators, has not been well documented yet. In this work, the mechanism behind the electron transfer from heme(ii) to riboflavin is investigated by using in situ ultraviolet visible and fluorescence spectroelectrochemical analysis, which provides the information regarding the structural change and electrochemical characteristics of species in the electron transfer process. It is found that hemin(iii), the oxidized form of heme(ii), is electrolyzed to an intermediate "hemx(ii)" without structural changes, and is then transformed to heme(ii) by conjugating with riboflavin and its radicals. Heme(ii) is able to activate riboflavin reduction via a two-electron two-proton pathway in aqueous solution. The mechanisms proposed on the basis of experimental results are further confirmed by density functional theory calculations. The results about the electron transfer from hemx(ii) (or heme(ii)) to riboflavin are useful not only for understanding the EET mechanisms, but also for maximizing the role of riboflavin in biogeochemical cycling and environmental bioremediation.

Effects of hyperbaric oxygen on hippocampal neuronal apoptosis in rats with acute carbon monoxide poisoning.

INTRODUCTION: Acute carbon monoxide (CO) poisoning causes serious health problems such as neuropsychological sequelae. This study aimed to investigate neuronal apoptosis and the effects of hyperbaric oxygen (HBO2) on different regions of the rat hippocampus after CO poisoning. METHODS: 90 mature male Sprague Dawley rats were randomly divided into three groups: the normal control group (NC group), the acute carbon monoxide-poisoned group (CO group) and the hyperbaric oxygen treatment group (HBO2 group). CO exposure included 0, 1, 3, 7, 14 and 21 treatment days, one exposure on the first day, and sacrifice on each of the following days. HBO2 exposure included treatment for 0, 1, 3, 7, 14 and 21 days, daily treatment after CO exposure, and sacrifice after the last HBO2 treatment on each of those days. Hematoxylin-eosin staining, immunohistochemical staining, immunofluorescence staining, and western blot analysis were performed to detect apoptosis in brain tissue samples. RESULTS: MMP-9 and caspase-3 were prominently increased by CO exposure and inhibited by HBO2 in the CA3 region in the hippocampus at one, three and seven days (immunohistochemical staining [IHC]: P ⟨ 0.05). Neu N and the ratio of Bcl-2/ BAX were prominently decreased by CO exposure and rescued by HBO2 in the CA3 region after seven days of treatment (IHC: P ⟨ 0.05). CONCLUSION: These findings indicated that neuronal apoptosis in the rat hippocampus could be induced by acute CO exposure, especially in the CA3 region. HBO2 could effectively inhibit neuronal apoptosis, especially in the CA3 region after seven days of treatment. The application of HBO2 to inhibit MMP-9 and apoptosis may contribute to brain recovery after acute CO poisoning.

POU2F2-oriented network promotes human gastric cancer metastasis.

BACKGROUND AND AIMS: Aberrant upregulation of POU2F2 expression has been discovered in metastatic gastric cancer (GC). However, the mechanisms underlying the aberrant upregulation and the potential functions of POU2F2 remain uncertain. DESIGN: The role and mechanism of POU2F2 in GC metastasis were investigated in gastric epithelial cells, GC cell lines and an experimental metastasis animal model by gain of function and loss of function. Upstream and downstream targets of POU2F2 were selected by bioinformatics and identified by luciferase reporter assay, electrophoretic mobility shift assay and chromatin immunoprecipitation PCR. The influence of miR-218 on its putative target genes (POU2F2, ROBO1 and IKK-ß) and GC metastasis was further explored via in vitro and in vivo approaches. RESULTS: Increased POU2F2 expression was detected in metastatic GC cell lines and patient samples. POU2F2 was induced by the activation of nuclear factor (NF)-κB and, in turn, regulated ROBO1 transcription, thus functionally contributing to GC metastasis. Finally, miR-218 was found to suppress GC metastasis by simultaneously mediating multiple molecules in the POU2F2-oriented network. CONCLUSIONS: This study demonstrated that NF-κB and the SLIT2/ROBO1 interaction network with POU2F2 as the central part may exert critical effects on tumour metastasis. Blocking the activation of the POU2F2-oriented metastasis network using miR-218 precursors exemplified a promising approach that sheds light on new strategies for GC treatment.

The lncRNA PVT1/miR-590-5p/FSTL1 axis modulates the proliferation and migration of airway smooth muscle cells in asthma.

OBJECTIVE: Asthma is a prevalent chronic inflammatory airway disease that is characterised by airway remodelling and airway hyperresponsiveness. Abnormal proliferation and migration of airway smooth muscle cells (ASMCs) contribute to airway remodelling in asthma. However, the molecular mechanism underlying an increased ASMC mass in asthma remains elusive. Herein, we aimed at investigating the regulation of lncRNA PVT1 on ASMCs and focussing on the mechanism in the proliferation and migration. METHODS: Expression levels of lncRNA PVT1 and miR-590-5p in the serum collected from 24 children with asthma and 10 control children were determined by qRT-PCR. ASMCs proliferation and migration prior to and post platelet-derived growth factor subunit B (PDGF-BB) stimulation were examined by CCK-8 test and transwell assay. Dual-luciferase reporter assay was performed to determine miR-590-5p interaction with lncRNA PVT1 and follistatin-like 1 (FSTL1). Expression of lncRNA PVT1, miR-590-5p, FSTL1, C-Myc, cyclin D1, and cyclin-dependent kinase 1 (CDK1) was tested by quantitative real-time PCR (qRT-PCR) and immunoblotting analysis. RESULTS: The expression level of lncRNA PVT1 was higher but the expression level of miR-590-5p was lower in the serum of children with asthma than in control children. The expression level of lncRNA PVT1 was negatively correlated with the expression level of miR-590-5p in asthma. LncRNA PVT1 was upregulated upon PDGF-BB stimulation. LncRNA PVT1 knockdown by its specific shRNA repressed PDGF-BB-induced promotion of proliferation and migration in ASMCs and triggered an elevated miR-590-5p along with declined C-Myc, cyclin D1, and CDK1. The effects of lncRNA PVT1 knockdown on PDGF-BB-induced ASMCs were lost upon miR-590-5p inhibition. MiR-590-5p targeted FSTL1 gene and declined its expression, thus suppressing ASMC proliferation and migration following PDGF-BB stimulation and downregulating C-Myc, cyclin D1, and CDK1 expressions. The effects of miR-590-5p on PDGF-BB-induced ASMCs were lost upon FSTL1 overexpression. CONCLUSION: These results support the notion that the lncRNA PVT1/miR-590-5p/FSTL1 axis modulates ASMCs proliferation and migration following PDGF-BB stimulation, providing a potential therapeutic target to attenuate airway remodelling in asthma.

3-(1H-Imidazo[4,5-f][1,10]phenanthrolin-2-yl)benzonitrile methanol solvate.

In the title compound, C(20)H(11)N(5)·CH(3)OH, the benzene ring is twisted by a small dihedral angle of 1.89 (11)° with respect to the imidazo[4,5-f][1,10]phenanthroline ring system. N-H⋯O and O-H⋯N hydrogen bonding is present in the crystal structure.

[Effect of tadalafil therapy upon penile cavernous tissues in spontaneously hypertensive rats].

UNLABELLED: OBJECTIVE; To observe the plasma concentration change of endothelin-1 (ET-1) and the histomorphological changes in penile cavernous body after administrating a continuous low dose of tadalafil into spontaneously hypertensive rats (SHR). METHODS: Forty SHR rats were randomly divided into four groups of blank group, placebo group, continuous low-dose group and intermittent dose group with 10 rats in each. The animals were administrated with different doses of tadalafil via an intragastric route. To observe the plasma concentration change of ET-1 and cellular morphological changes of penile cavernous tissue in SHR after four weeks, the immunohistochemical method of SABC was employed to detect the expression of alpha-smooth muscle actin (alpha-SMA) in penile corpora cavernous of different groups. RESULTS: The plasma levels of ET-1 were lower in continuous low dose group (12.0 +/- 1.6) and intermittent dose group (14.3 +/- 1.7) as compared with the blank (18.0 +/- 1.9) and placebo groups (17.6 +/- 2.2) (all P < 0.01). And there was significant difference between the continuous low dose and intermittent dose groups (P < 0.05). The A-value level of absorbance in alpha-SMA were significantly different with the blank (0.53 +/- 0.03) and placebo groups (0.52 +/- 0.05) (P > 0.05) and it was lower in the continuous low dose group (0.29 +/- 0.03) than the intermittent dose group (0.38 +/- 0.03) (P < 0.05). It can be observed microscopically that in blank group and placebo group: endothelial cell and vascular smooth muscle cells of penile cavernous tissue in SHR had a disorderly distribution. The disrupted continuity and integrity of endothelial cell were also found. And they improved in continuous low dose group and intermittent dose group, especially the former; it can be viewed under TEM that the endothelial cells of penile cavernous tissue in SHR had mostly reverted to normal condition in the continuous low dose group and its ultra-structure indicated that the tissue morphology improved. CONCLUSION: A continuous low dose of tadalafil can improve the function and structure of vascular endothelium in penile cavernous body. Thus it provides rationales for a continuous low dose of PDE5 inhibitor in the treatment of erectile dysfunction.

Framework of Cytochrome/Vitamin B2 Linker/Graphene for Robust Microbial Electricity Generation.

A bioelectrochemical system (BES) allows direct electricity production from wastes, but its low-power density, which is mainly associated with its poor anodic performance, limits its practical applications. Here, the anodic performance of a BES can be significantly improved by electrodepositing vitamin B2 (VB2) onto a graphene [reduced graphene oxide (rGO)]-modified glassy carbon electrode (VB2/rGO/GC) with Geobacter sulfurreducens as the model microorganisms. The VB2/rGO/GC electrode results in 200% higher electrochemical activity than a bare GC anode. Additionally, in microbial electrolysis cells, the current density of this composite electrode peaks at ∼210 µA cm-2 after 118 h and is maintained for 113 h. An electrochemical analysis coupled with molecular simulations reveals that using VB2 as a linker between the electrochemically active protein of this model strain and the rGO surface accelerates the electron transfer, which further improves the bioelectricity generation and favors the long-term stability of the BES. The VB2 bound with a flexible ribityl group as the organic molecular bridge efficiently mediates energy conversion in microbial metabolism and artificial electronics. This work provides a straightforward and effective route to significantly enhance the bioenergy generation in a BES.

[Observation on therapeutic effect of compound anesthesia of transcutaneous electrical point stimulation and Remifentanil].

OBJECTIVE: To assess the value of compound anesthesia of transcutaneous electrical point stimulation and Remifentanil and the efficacy of this method on postoperative acute pain. METHODS: Sixty cases with vertebral lamina internal fixation decompression operation were selected and randomly divided into 2 groups, an observation group and a control group, 30 cases in each group. The patients in the observation group received compound anesthesia of transcutaneous electrical point stimulation at Hegu (LI 4), Laogong (PC 8), Neiguan (PC 6) and Waiguan (TE 5) 30 min before anesthesia induction with HANS stimulator and then Remifentanil anesthesia. During the operation, the stimulation was lasted for 30 min and ceased for 30 min until the end of operation. The patients in the control group received simple Remifentanil anesthesia. The dosage of the narcotic, changes of both blood pressure and heart rate during operation, before and after extubation and the pain degree, etc. were investigated in the two groups. RESULTS: (1) The dosage of Isoflurane, (0.52 +/- 0.33)vol%, in the observation group was significantly lower than (1.12 +/- 0.18) vol% in the control group (P < 0.01). (2) Both blood pressure and heart rate during operation, before and after extubation in the observation group were lower than those before operation (P < 0.01), and both the blood pressure and heart rate during operation in the control group were lower than those before operation (P < 0.01). The blood pressure after extubation in the observation group was significantly lower than that of the control group (P < 0.01), and the heart rate before and after extubation in the observation group was significantly lower than that of the control group (P < 0.01). (3) The time of extubation and palinesthesia in the observation group were significantly shorter than those in the control group (P < 0.01). (4) In the observation group, the VAS scores after palinesthesia in 26 cases were < 4, and in 4 cases were > or = 5, while in the control group, the scores in 4 cases were < 4 and in 20 cases > or = 5, with a significant difference between the two groups (P < 0.01). CONCLUSION: Compound anesthesia of transcutaneous electrical point stimulation and Remifentanil can reduce the dosage of narcotics, shorten the time of palinesthesia and effectively prevent and treat acute pain after Remifentanil anesthesia.

[Survival status of stage IV non-small cell lung cancer patients after radiotherapy--a report of 287 cases].

BACKGROUND & OBJECTIVE: The patients with stage IV non-small cell lung cancer (NSCLC) usually need radiotherapy and have good responses, particularly in those with brain or bone metastases. This study was to evaluate the influence of radiotherapy on the survival of stage IV NSCLC patients. METHODS: Clinical data of 287 patients with stage IV NSCLC were retrospectively analyzed. Whole brain was treated with two parallel fields irradiation; bone metastases were treated with one local field irradiation. Primary tumors, regional lymph nodes and other distant metastases were treated by conventional fractionation radiotherapy or 3-dimensional conformal radiotherapy. Whole brain and bone radiotherapy was delivered with a total dose of 40 Gy in 20 fractions in 4 weeks or with a total dose of 30 Gy in 10 fractions in 2 weeks. The median dose for primary tumors and regional lymph nodes was 50 Gy (20-70 Gy), and the median dose for other distant metastases was 46 Gy (40-60 Gy). RESULTS: The median survival time of the 287 patients was 9 months (8-10 months). The 1- and 2-year overall survival rates were 30.2% and 8.9%. The median survival time was significantly longer in the patients received chemotherapy than in the patients didn't (10 months vs. 8 months, P = 0.049). In the patients with brain, bone, or other distant metastases, the median survival time was 8, 9, and 10 months, respectively; the 1-year survival rates were 24.8%, 28.7%, and 37.5%, respectively; the 2-year survival rates were 6.7%, 7%, and 15.3%, respectively. By unitivariate analysis, histological type and patients' age were prognostic factors of NSCLC. The median survival time was significantly longer in adenocarcinoma patients than in squamous cell carcinoma patients and other carcinoma patients (10 months vs. 7 and 9 months, P = 0.046), longer in the patients of < or =60 years old than in those of >60 years old (11 months vs. 8 months, P = 0.012), and longer in the patients with only bone metastases than in the patients with concomitant other distant metastases (10 months vs. 6 months, P = 0.033), but there was no significant difference between the patients with only brain metastases and those with concomitant other distant metastases (9 months vs. 8 months, P = 0.374). Radiotherapy for primary tumors and lymph nodes, complications of other chronic diseases, and irradiation dose and pattern had no effect on the survival. CONCLUSIONS: Histological type and patients' age may affect the efficacy of radiotherapy on stage IV NSCLC. The irradiation patterns of 40 Gy in 20 fractions in 4 weeks or 30 Gy in 10 fractions in 2 weeks have no effect on the survival of patients with brain or bone metastases.