A pathway for chitin oxidation in marine bacteria.

Oxidative degradation of chitin, initiated by lytic polysaccharide monooxygenases (LPMOs), contributes to microbial bioconversion of crystalline chitin, the second most abundant biopolymer in nature. However, our knowledge of oxidative chitin utilization pathways, beyond LPMOs, is very limited. Here, we describe a complete pathway for oxidative chitin degradation and its regulation in a marine bacterium, Pseudoalteromonas prydzensis. The pathway starts with LPMO-mediated extracellular breakdown of chitin into C1-oxidized chitooligosaccharides, which carry a terminal 2-(acetylamino)-2-deoxy-D-gluconic acid (GlcNAc1A). Transmembrane transport of oxidized chitooligosaccharides is followed by their hydrolysis in the periplasm, releasing GlcNAc1A, which is catabolized in the cytoplasm. This pathway differs from the known hydrolytic chitin utilization pathway in enzymes, transporters and regulators. In particular, GlcNAc1A is converted to 2-keto-3-deoxygluconate 6-phosphate, acetate and NH3 via a series of reactions resembling the degradation of D-amino acids rather than other monosaccharides. Furthermore, genomic and metagenomic analyses suggest that the chitin oxidative utilization pathway may be prevalent in marine Gammaproteobacteria.

Pectin gels based on H+/(NH4)2SO4 and its potential in sustained release of NH4.

A gelling strategy for HP was proposed in this study, ammonium sulfate (AS) as a co-solute could induce the gelling of HP in acidic environment. The solubility and Zeta potential of HP dramatically decreased in AS solution, which indicated AS could promote the aggregation of HP. The rheological results confirmed the gelling of HP (G' > G″) with AS: 25-30 wt% and pH ≤ 3.0, and the gel strength is mainly depended on HP rather than AS concentration. Smaller AS crystals (SEM) and reduced T2 values (LF-NMR) were observed in HP gels, suggested the gel network of HP could limit the migration of AS and water. Finally, it was found that the release process of NH4+ in HP + AS gel was lagged behind that of pure AS, which verified the potential of HP + AS gel in the field of sustained-release fertilizers.

Physicochemical characteristics and functional properties of high methoxyl pectin with different degree of esterification.

Moderate alkali de-esterification can change the physicochemical characteristics and thus the functional properties of high methoxyl pectin (HMP). The results revealed that de-esterification could increase negative charges (Zeta potential from -21 to -31 mV), decrease molecular weight (from 448 to 136 kDa) and apparent viscosity of HMP. Homogalacturonan (HG) content decreased (from 62% to 49%) while rhamnogalacturonan Ⅰ (RG-Ⅰ) content increased (from 32% to 46%) after de-esterification. The group characteristics of HMP with different degree of esterification (DE) were similar and no obvious impact was made on degree of crystallinity by alkali de-esterification. A conformation transition of HMP molecule implied by Congo red test were occurred as the DE decreased. With the decrease of DE, the molecular structure of HMP became shorter and smaller, and the entanglement was weaker. The de-esterification caused slight decrease of thermal stability. Alkali de-esterification would weaken the gel property and the emulsifying ability of HMP.

Active site architecture of an acetyl xylan esterase indicates a novel cold adaptation strategy.

SGNH-type acetyl xylan esterases (AcXEs) play important roles in marine and terrestrial xylan degradation, which are necessary for removing acetyl side groups from xylan. However, only a few cold-adapted AcXEs have been reported, and the underlying mechanisms for their cold adaptation are still unknown because of the lack of structural information. Here, a cold-adapted AcXE, AlAXEase, from the Arctic marine bacterium Arcticibacterium luteifluviistationis SM1504T was characterized. AlAXEase could deacetylate xylooligosaccharides and xylan, which, together with its homologs, indicates a novel SGNH-type carbohydrate esterase family. AlAXEase showed the highest activity at 30 °C and retained over 70% activity at 0 °C but had unusual thermostability with a Tm value of 56 °C. To explain the cold adaption mechanism of AlAXEase, we next solved its crystal structure. AlAXEase has similar noncovalent stabilizing interactions to its mesophilic counterpart at the monomer level and forms stable tetramers in solutions, which may explain its high thermostability. However, a long loop containing the catalytic residues Asp200 and His203 in AlAXEase was found to be flexible because of the reduced stabilizing hydrophobic interactions and increased destabilizing asparagine and lysine residues, leading to a highly flexible active site. Structural and enzyme kinetic analyses combined with molecular dynamics simulations at different temperatures revealed that the flexible catalytic loop contributes to the cold adaptation of AlAXEase by modulating the distance between the catalytic His203 in this loop and the nucleophilic Ser32. This study reveals a new cold adaption strategy adopted by the thermostable AlAXEase, shedding light on the cold adaption mechanisms of AcXEs.

Structural characterization of pectin-bismuth complexes and their aggregation in acidic conditions.

Bismuth-contained therapies are effective in treating gastric ulcer and eliminating Helicobacter pylori (Hp). Anion polysaccharides ligand could reduce the intake of bismuth, and enhance drug efficacy of bismuth compounds. In this study, pectin-bismuth (PB) was prepared and the changes of PB structure in acidic environment were reported for the first time. The structure of PB was characterized by FT-IR, XRD, and TGA, which suggested that combined with bismuth could alter the crystal structure of pectin. XPS confirmed the ionic binding of Bi3+ with carboxyl groups of pectin. The aggregating of PB with different pH level were also investigated, and the influence of pH on PB structure were observed by SEM. Results showed that PB has much larger volume of flocculation in acidic environment compared with bismuth nitrate. Additionally, apparent shear stress (τa) of PB suspension was evaluated. These results revealed the structural characteristics and acid-induced aggregation of pectin-bismuth, and bismuth could aggregate in acidic solution with the gelation of pectin.

Study on a Novel Cold-Active and Halotolerant Monoacylglycerol Lipase Widespread in Marine Bacteria Reveals a New Group of Bacterial Monoacylglycerol Lipases Containing Unusual C(A/S)HSMG Catalytic Motifs.

Monoacylglycerol lipases (MGLs) are present in all domains of life. However, reports on bacterial MGLs are still limited. Until now, reported bacterial MGLs are all thermophilic/mesophilic enzymes from warm terrestrial environments or deep-sea hydrothermal vent, and none of them originates from marine environments vastly subject to low temperature, high salts, and oligotrophy. Here, we characterized a novel MGL, GnMgl, from the marine cold-adapted and halophilic bacterium Glaciecola nitratireducens FR1064T. GnMgl shares quite low sequence similarities with characterized MGLs (lower than 31%). GnMgl and most of its bacterial homologs harbor a catalytic Ser residue located in the conserved C(A/S)HSMG motif rather than in the typical GxSxG motif reported on other MGLs, suggesting that GnMgl-like enzymes might be different from reported MGLs in catalysis. Phylogenetic analysis suggested that GnMgl and its bacterial homologs are clustered as a separate group in the monoglyceridelipase_lysophospholipase family of the Hydrolase_4 superfamily. Recombinant GnMgl has no lysophospholipase activity but could hydrolyze saturated (C12:0-C16:0) and unsaturated (C18:1 and C18:2) MGs and short-chain triacylglycerols, displaying distinct substrate selectivity from those of reported bacterial MGLs. The substrate preference of GnMgl, predicted to be a membrane protein, correlates to the most abundant fatty acids within the strain FR1064T, suggesting the role of GnMgl in the lipid catabolism in this marine bacterium. In addition, different from known bacterial MGLs that are all thermostable enzymes, GnMgl is a cold-adapted enzyme, with the maximum activity at 30°C and retaining 30% activity at 0°C. GnMgl is also a halotolerant enzyme with full activity in 3.5M NaCl. The cold-adapted and salt-tolerant characteristics of GnMgl may help its source strain FR1064T adapt to the cold and saline marine environment. Moreover, homologs to GnMgl are found to be abundant in various marine bacteria, implying their important physiological role in these marine bacteria. Our results on GnMgl shed light on marine MGLs.

Emulsifying properties of high methoxyl pectins in binary systems of water-ethanol.

Pectin is widely distributed in plant cell wall, most of which have limited emulsifying properties. Ethanol could alter the solubility of pectin, and affect its emulsifying properties. No creaming and breaking of emulsion appeared in 21% (v/v) ethanol contained emulsion. This project investigated the influence of ethanol (0%-35%, v/v) on conformation and emulsifying properties of pectin. Results shown that ethanol could reduce the helix conformation and zeta potential of pectin chain, which leading to compact conformation and enhanced interaction among pectin molecules. Although emulsion droplet diameter increased with ethanol content, the most stable emulsion was found in 21% (v/v) ethanol. CLSM also indicated over-aggregated pectin have a poor adsorption capacity on the interface of O/W. All results manifested the emulsifying properties of pectin can be improved by 21% (v/v) ethanol. This study provides a new strategy to improve the emulsifying property of pectin by changing its conformation.

Structural Insight Into Chitin Degradation and Thermostability of a Novel Endochitinase From the Glycoside Hydrolase Family 18.

Bacterial endochitinases play important roles in environmental chitin degradation and have good applications. Although the structures of some endochitinases, most belonging to the glycoside hydrolase (GH) family 18 and thermostable, have been reported, the structural basis of these enzymes for chitin degradation still remain unclear due to the lack of functional confirmation, and the molecular mechanism for their thermostability is also unknown. Here, we characterized a GH18 endochitinase, Chi23, from marine bacterium Pseudoalteromonas aurantia DSM6057, and solved its structure. Chi23 is a thermostable enzyme that can non-processively hydrolyze crystalline and colloidal chitin. Chi23 contains only a catalytic domain that adopts a classical (ß/α)8 TIM-barrel fold. Compared to other GH18 bacterial endochitinases, Chi23 lacks the chitin-binding domain and the ß-hairpin subdomain, indicating that Chi23 has a novel structure. Based on structural analysis of Chi23 docked with (GlcNAc)5 and mutational analysis, the key catalytic residue (Glu117) and seven substrate-binding residues (Asn9, Gln157, Tyr189, Asn190, Asp229, Trp260, and Gln261) are revealed. Among these identified residues, Asn9, Asp229 and Gln261 are unique to Chi23, and their cumulative roles contribute to the activity of Chi23 against both crystalline and soluble chitin. Five substrate-binding residues (Tyr189, Asn190, Asp229, Trp260, and Gln261) are found to play important roles in maintaining the thermostability of Chi23. In particular, hydrogen bond networks involving Asp229 and Gln261 are formed to stabilize the protein structure of Chi23. Phylogenetic analysis indicated that Chi23 and its homologs represent a new group of GH18 endochitinases, which are widely distributed in bacteria. This study sheds light on the molecular mechanism of a GH18 endochitinase for chitin degradation.

The Molecular Mechanism of EPO Regulates the Angiogenesis after Cerebral Ischemia through AMPK-KLF2 Signaling Pathway.

OBJECTIVE: In this study, the molecular mechanism by which EPO regulates the angiogenesis after cerebral ischemia through AMPK-KLF2 signaling pathway was investigated. METHODS: Sixty healthy, male, C57BL/6 mice were randomly divided into three groups of 20 mice: a sham group, the middle cerebral artery occlusion (MCAO) group, and a MCAO+EPO treatment group. The MCAO model was established using a modified ZeaLonga method. Mice in the EPO treatment group were injected with EPO immediately after reperfusion (5000 IU/kg), and EPO was injected the following day. The number of mouse deaths and neurologic function scores were recorded during the experiment. On day 7 after cerebral ischemia, brain tissue proteins were extracted. The following proteins expressions were detected by western blot assay: EPO, vascular endothelial growth factor (VEGE), vascular endothelial growth factor receptor (KDR), adenosine activated protein kinase (AMPK), and alpha HIF-1α alpha (HIF-1α), KLF2 and nitric oxide synthase (eNOS). RESULTS: Compared with the MCAO group, the survival rate of mice in the EPO group was significantly improved and neurological function was significantly improved (P < 0.01). Western blot results showed that the content of EPO in brain tissue in MCAO group significantly increased compared with sham group. The content of EPO in the brain tissue of mice in the MCAO+EPO treatment group was significantly higher than in that of the MCAO group, which indicates that EPO increased the content of EPO in mouse brain tissue. Compared with the sham group, the protein expression of vascular endothelial growth factor (VEGE) and its receptor (KDR) in brain tissue of the MCAO group significantly decreased. However, the protein expression of VEGE and its receptor KDR in brain tissue of rats treated with MCAO+EPO was significantly higher than in that of the MCAO group. Thus, in this study, EPO was associated with vascular endothelial differentiation after cerebral ischemia in mice. The results of AMPK and KLF2 showed that the expression levels of AMPK and KLF2 in brain tissues of MCAO group mice significantly decreased compared with the sham group. However, the expression levels of AMPK and KLF2 in brain tissues of mice treated with MCAO+EPO were significantly higher than those in the MCAO group. Thus, EPO can activate AMPK and upregulate the expression of the transcription factor KLF2. The protein expression of HIF-1α in the brain tissue of mice in the MCAO group significantly increased compared with the sham group. However, the expression of HIF-1α in mice brain tissues in the MCAO+EPO treatment group was significantly lower than in that of the MCAO group, indicating that EPO was involved in regulating HIF-1α expression. The eNOS results showed that, compared with Sham group, the protein expression of eNOS in brain tissue of MCAO group mice significantly decreased. In the MCAO+EPO treatment group, the protein expression of eNOS was significantly higher in the brain tissue of the mice than in that of the MCAO group, indicating that EPO was involved in the synthesis of NO and promoted the angiogenesis. CONCLUSION: EPO promotes VEGE and its receptor (KDR) expression and participates in the regulation of HIF-1α and eNOS protein expression through the activation of AMPK-KLF2 signaling pathways to promote new vascular development after cerebral ischemia.

Apoptosis Inducing Factor Is Involved in Stretch-Induced Apoptosis of Myoblast via a Caspase-9 Independent Pathway.

The apoptosis of myoblast in response to excessive cyclic stretch is crucial in adaptive construction of skeletal muscles in orthopedic functional therapy. Mitochondria signaling pathway is the central links in the execution of the intrinsic apoptotic cascade, but its molecular mechanism in stretch-induced apoptosis in myoblasts remains incompletely understood. The aim of this study was to investigate the mechanobiological roles of caspase-9 and Apoptosis Inducing Factor (AIF), two important components in mitochondrial pathway, in stretch-induced apoptosis of myoblast. Hoechst 33258 was used to observe apoptotic cells morphologically and flow cytometry to analyze apoptosis rate of myoblasts. Protein and mRNA of caspase-9 and AIF were detected by Western blotting and RT-PCR. Furthermore, caspase-9 specific inhibitor z-LEHD-fmk was applied to clear the mechanism of caspase-9 pathway in stretch-induced apoptosis. We found that apoptotic rate induced by cyclic stretch increased in a time-dependent manner, and the same tendency of mRNA and protein of caspase-9 and AIF. Caspase-9 inhibition reduced stretch-induced apoptosis, but had no effect on expression of AIF. We concluded that caspase-9 and AIF played an important role in stretch-induced apoptosis in myoblast, and AIF was involved in the process in a caspase-9 independent way. J. Cell. Biochem. 118: 829-838, 2017. © 2016 Wiley Periodicals, Inc.

The Screening Performance of Serum 1,3-Beta-D-Glucan in Patients with Invasive Fungal Diseases: A Meta-Analysis of Prospective Cohort Studies.

The serum 1,3-beta-D-glucan (BG) assay aids in the early diagnosis of invasive fungal diseases (IFDs) and has been approved for their diagnosis. However, reports on the screening performance of BG are scarce. We performed a meta-analysis of data extracted from only prospective cohort studies to evaluate the screening performance of the BG assay in the diagnosis of IFDs. We specifically searched 4 databases (the PubMed, Web of Science, Elsevier, and Cochrane Collaboration databases) according to EORTC-MSG criteria. A total of 1068 patients in 11 studies were analyzed. Deeks' funnel plot asymmetry test suggested a low likelihood of publication bias for the included studies (p = 0.055). The pooled sensitivity, specificity, positive likelihood ratio, negative likelihood ratio, diagnostic odds ratio, and area under the summary receiver operating characteristic curve, with 95% confidence intervals, were 0.75(0.63,0.84), 0.87(0.81,0.92), 5.85(3.96,8.63), 0.30(0.20,0.45), 19.53(11.16,34.18), and 0.89(0.86,0.91), respectively. The findings of this meta-analysis suggest that the BG assay is a useful screening tool with high sensitivity and specificity for discriminating between patients with and without IFDs. In clinical practice, BG assay results should be evaluated together with clinical and microbiological findings.

[Exploring the stem cell surface markers expressed in human dental pulp stem cells].

PURPOSE: To explore the stem cell surface markers expressed in human dental pulp stem cells which were selected and isolated by magnetic beads. METHODS: Human dental pulp cells (hDPCs) were separated and cultured from dental pulp of healthy third molars for orthodontic purpose. HDPSCs were isolated from cultured hDPCs by magnetic-activated cell sorting's (MACS) indirect magnetic cell labeling and positive selection strategy with antibody STRO-1 in the 2nd generation. Then the stem cell surface markers (CD73, CD90, CD105, CD166 and STRO-1) were respectively detected in 3, 4, 5, 6, 7 and 8 generation of dental pulp stem cells. HDPSCs were induced to differentiation by adipogenic medium and osteogenic medium in the 3rd generation. Adipogenic differentiation was assessed by oil red O staining in day 21, and osteogenic differentiation was assessed by alizarin red staining in day 21. RESULTS: HDPSCs could differentiate into adipocyte and osteoblasts. Oil red O staining and alizarin red staining were positively expressed after induction of HDPSCs. STRO-1's expression was decreased with the increase of generation. The expressions of CD73, CD90, CD105 and CD166 were relatively stable. CONCLUSIONS: The expression of STRO-1 is declined with the increase of generation, and the expressions of CD73, CD90, CD105 and CD166 are relatively stable with the changes of generation. Supported by National Natural Science Foundation of China (81070826/81371143) and Shanghai Rising-Star Program (12QH1401400).

[Immortalization of human dental pulp stem cells caused by transferring hTERT gene].

PURPOSE: To establish an immortalized human dental pulp stem cell line used for basic and clinical research of oral science. METHODS: Human telomerase reverse transcriptase (hTERT) cDNA was transferred into human dental pulp stem cells (hDPSCs) by lentivirus. The resultant stable clones reproduced successively and the expression of hTERT was identified. RESULTS: The hTERT gene was transferred into human dental pulp stem cells successfully. The transformed cells expressed telomerase activity and divided vigorously. p35 had been obtained so far. CONCLUSIONS: The hDPSCs can be immortalized by transferring exogenous hTERT gene to constitute telomerase activity.

The impact of various time intervals on the supragingival plaque dynamic core microbiome.

OBJECTIVE: The aim of this study was to examine the influence of various time intervals on the composition of the supragingival plaque microbiome, especially the dynamic core microbiome, and to find a suitable observation interval for further studies on oral microbiota. METHODS AND MATERIALS: Eight qualified volunteers whose respective age ranges from 25 to 28 years participated in the present study. The supragingival plaque was collected from the buccogingival surface of the maxillary first molar at eight time slots with different intervals (day 0, 1 day, 3 days, 1 week, 2 weeks, 3 weeks, 1 month, and 3 months). Bioinformatic analyses was performed based on 16S rDNA pyrosequencing (454 sequencing platform) targeting at the hypervariable V4-V5 region, in order to assess the diversity and variation of the supragingival plaque microbiome. RESULTS: A total of 359,565 qualified reads for 64 samples were generated for subsequent analyses, which represents 8,452 operational taxonomic units identified at 3% dissimilarity. The dynamic core microbiome detected in the current study included five phyla, 12 genera and 13 species. At the genus level, the relative abundance of bacterial communities under the "1 day," "1 month," and "3 months" intervals was clustered into sub-category. At the species level, the number of overlapping species remained stable between the "1 month" and "3 months" intervals, whereas the number of dynamic core species became stable within only 1 week. CONCLUSIONS: This study emphasized the impact of different time intervals (days, weeks and months) on the composition, commonality and diversity of the supragingival microbiome. The analyses found that for various types of studies, the time interval of a month is more suitable for observing the general composition of the supragingival microbiome, and that a week is better for observing the dynamic core microbiome.

[Complementation and function of methyl-metabolic pathway in Streptococcus mutans luxS null strain].

PURPOSE: To complement the activated methyl cycle (AMC) pathway at an AI-2 defect background in Streptococcus mutans (S. mutans) luxS null strain. METHODS: A sahH gene was amplified from Pseudomonas aeruginosa and introduced into the S. mutans luxS null strain to complement the methyl-metabolic disruption at an AI-2 defect background. Western blot, reverse-transcription PCR and AI-2 bioassay were performed to confirm the heterogenous expression of SahH in S. mutans luxS null strain. The data was statistically analyzed by SAS8.0 software package. RESULTS: LuxS and SahH were detected to express in Escherichia coli BL21 as well as their mRNA were confirmed to be successfully transcribed in S. mutans luxS null strain. AI-2 production was found in wide type S. mutans and its luxS-introduced luxS null strain but not found in the luxS null strain and its sahH and empty plasmid-introduced strains. CONCLUSIONS: A new S. mutans derivative with the AMC pathway complements while the AI-2 defect is constructed.

[Clinical value of extravascular lung water and preload parameters in weaning of mechanical ventilation in patients with septic shock].

OBJECTIVE: To investigate the values of extravascular lung water and preload parameters of weaning from mechanical ventilation on patients with septic shock. METHODS: A prospective study was conducted. A total of 52 septic shock patients with mechanical ventilation were enrolled from January 2010 to July 2012. All patients were treated and monitored by pulse induced continuous cardiac output (PiCCO) till they reached weaning criteria, and then spontaneous breathing trial (SBT), weaning, and extubation were performed in turn. The enrolled patients were divided into two groups including successful weaning group (n=38) and weaning failure group (n=14) according to clinical manifestations during 48 hours after weaning. Extravascular lung water index (EVLWI), preload parameters such as global end diastolic volume index (GEDVI) and intra-thoracic blood volume index (ITBVI), pulmonary vascular permeability index (PVPI) and N-terminal pro-B-type natriuretic peptide (NT-proBNP) were compared at the time before weaning, 0.5 hour after weaning, 0.5 hour after extubation, and time of weaning failure or 48 hours after weaning. The patients in weaning failure group were sub-divided into high PVPI group (PVPI≥1.5 ml/m(2)) and low PVPI group (PVPI<1.5 ml/m(2)), the NT-proBNP and pulmonary blood volume (PBV) were compared between two groups. RESULTS: Before weaning, there was no statistical difference in NT-proBNP, volume parameters and EVLWI between two groups. EVLWI, GEDVI, ITBVI, PVPI and log NT-proBNP were gradually increased after weaning and extubation in two groups. The EVLWI, PVPI and log NT-proBNP were significantly higher at end point of observation in weaning failure group compared with those in successful weaning group (EVLWI: 12.81±2.13 ml/kg vs. 8.48±1.53 ml/kg, PVPI: 2.79±1.29 ml/m(2) vs. 2.19±0.94 ml/m(2), log NT-proBNP: 3.72±0.35 vs. 3.44±0.28, P<0.05 or P<0.01). GEDVI, ITBVI at 0.5 hour after weaning and end point of observation in weaning failure group were significantly higher than those in successful weaning group (0.5 hour after extubation: GEDVI 986.29±166.44 ml/m(2) vs. 856.47±149.15 ml/m(2), ITBVI: 1171.07±167.03 ml/m(2) vs. 1045.79±146.09 ml/m(2); end point of observation: GEDVI 957.00±67.25 ml/m(2) vs. 816.86±27.58 ml/m(2), ITBVI: 1184.29±209.68 ml/m(2) vs. 993.79±168.90 ml/m(2), P<0.05 or P<0.01). Sub-analysis showed that in weaning failure group, higher log NT-proBNP and PBV were found in patients with low PVPI compared with those with high PVPI (log NT-proBNP: 4.02±0.11 vs. 3.71±0.23, PBV: 507.19±25.72 ml vs. 347.85±47.52 ml, P<0.05 and P<0.01). CONCLUSIONS: Increased EVLW is the reason of pulmonary edema caused by weaning in septic shock patients, to which both hydrostatic and pulmonary permeability may contribute, and the latter could be more important. Monitoring preload parameters could help distinguish the mechanism of pulmonary edema after weaning, which may be useful in treatment.

Combined fenton oxidation and biological activated carbon process for recycling of coking plant effluent.

Fenton oxidation and coagulation-flocculation-sedimentation (CFS) were both effective in removing many organic constituents of the biotreated coking plant effluent before the final treatment in an activated carbon adsorber. Fenton oxidation broke down most persistent organic pollutants and complex cyanides present in the feed stream and caused the eventual biodegradation of the organic residues in the adsorber. The results of Fenton oxidation followed by adsorption and biodegradation in two biological activated carbon (BAC) adsorbers show that the combined treatment consistently produced a high quality final effluent of <50mg/L in COD(Cr) and <0.5mg/L in total cyanide during the 70-d study without replacing any activated carbon. The BAC function of the adsorber substantially reduced the need for replacing activated carbon making the combined Fenton oxidation-BAC treatment process a cost effective treatment process to recycle the final effluent for many beneficial reuses while meeting the much more stringent discharge limits of the future.

[Prognostic implication of plasma N-terminal-pro-brain natriuretic peptide in weaning from mechanical ventilation].

OBJECTIVE: To explore the relationship between plasma N-terminal-pro-brain natriuretic peptide (NT-proBNP) levels of patients before weaning and outcome of weaning from mechanical ventilation (MV) in patients. METHODS: A total of 126 intensive care unit (ICU) patients with MV were enrolled from August 2008 to December 2009, and the cause composition was recorded. Plasma NT-proBNP levels were measured in patients with MV, in whom the clinical data had fulfilled the criteria for weaning from MV, spontaneous breathing trial, weaning and extubation were performed successively. The enrolled patients were divided into two groups namely success group and failure group according to weaning outcome within 48-hour. The plasma NT-proBNP levels in two groups were compared, and receiver operating characteristic (ROC) curve for predicted weaning outcome was plotted to find the cut-off point value of NT-proBNP. RESULTS: The major causes of MV were pulmonary infection (33.3%) and surgical operations (30.2%), and heart failure accounted for only 11.9%. The plasma NT-proBNP levels before weaning were negatively correlated with the consequences of weaning. The plasma NT-proBNP levels in failure group (n=38) were significantly higher than those in success group (n=88, lg NT-proBNP: 3.97+/-0.48 vs. 2.99+/-0.67 ,P<0.05). The NT-proBNP area under ROC curve was 0.875+/-0.043 [95% confidence interval (95% CI) was 0.792-0.959]. The cut-off point value which could be used to predict the outcome of weaning was 3 914.5 ng/L. The sensitivity and specificity of the cut-off point value were 78.3% and 91.1%, respectively. CONCLUSION: Irrespective of the causes of institution of MV, the cardiac function must be considered as an important factor in affecting the outcome of weaning. The plasma NT-proBNP level of 3 914.5 ng/L can be used to predict weaning outcome. The cardiac function should be improved to a point within the range of cut-off point value in order to improve the success rate of weaning.