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1.
ACS Sens ; 9(6): 3367-3376, 2024 Jun 28.
Article in English | MEDLINE | ID: mdl-38885468

ABSTRACT

Instability is a key challenge for current pH sensors in practical applications, especially in aquatic environments with high biomass and redox substances. Herein, we present a novel approach that uses a highly stable IrOx sensing layer enveloped in a composite film of SPEEK doped with a silicon-stabilized ionic liquid (SP-IrOx). This design mitigates drift due to sensitive layer variations and minimizes interference from complex external conditions. After exhibiting robustness under moderately reducing conditions caused by S2-, I-, and ascorbic acid, the SP-IrOx sensor's efficacy was validated through real-time pH measurements in demanding aquatic settings. These included laboratory algal culture medium, sediment substrates, and mussel aquaculture areas. The sensor sustained accuracy and stability over extended periods of 6-8 days when compared to calibrated commercial electrodes. The deviations from reference samples were minimal, with a variance of no more than 0.03 pH units in mussel aquaculture areas (n = 17) and 0.07 pH units in an algal culture medium (n = 37). As a potentiometric, this solid-state electrode features a compact structure and low energy consumption, making it an economical and low-maintenance solution for precise pH monitoring in diverse challenging environments with high biomass and turbidity.


Subject(s)
Biomass , Hydrogen-Ion Concentration , Electrodes , Animals , Aquaculture , Bivalvia/chemistry
2.
J Agric Food Chem ; 72(12): 6444-6453, 2024 Mar 27.
Article in English | MEDLINE | ID: mdl-38502525

ABSTRACT

The development of efficient, biobased polyurethane controlled-release fertilizers from sustainable and eco-friendly biomaterials has received increased research attention, owing to concerns regarding global food security and environmental sustainability. Most previous studies focused on replacing petroleum-based polyols with biopolyols; however, the other main raw material, isocyanate, remained a petrochemical product. Herein, all-natural, plant-derived polyurethane-coated urea was successfully developed using castor oil and biobased isocyanate, and the performance of the coating shell before and after modification was compared. The results showed that the incorporation of a low dose of lauric acid copper into the coating material simultaneously enhanced the hydrophobicity and elasticity of the all-biobased polyurethane membrane, which prolonged the nitrogen release longevity from 3 to 112 days. In addition, the modified membrane showed excellent biodegradability in a soil environment. The novel all-biobased polyurethane coating material and modification technique provide insight for developing sustainable and eco-friendly controlled-release fertilizers.


Subject(s)
Fertilizers , Polyurethanes , Delayed-Action Preparations , Polymers , Isocyanates
3.
Article in English | MEDLINE | ID: mdl-37072569

ABSTRACT

Emergence delirium (ED) is a common mental complication during recovery from anesthesia. However, studies on the effects of esketamine, an intravenous anesthetic for pediatrics, on ED are still lacking. This study aimed to investigate the effects of a single-dose of esketamine during anesthesia induction on ED after minor surgery in preschool children. A total of 230 children (aged 2-7 years) completed the study. The exposed group (0.46 mg kg-1: average dose of esketamine) was associated with an increased incidence of ED and a higher maximum Pediatric Anesthesia Emergence Delirium score than the non-exposed group. The length of post-anesthesia care unit stay was longer in the exposed group than the non-exposed group. In contrast, extubation time, face, legs, activity, cry, and consolability (FLACC) scores, and the proportions of rescue analgesics were comparable between the two groups. Furthermore, five factors, including preoperative anxiety scores, sevoflurane and propofol compared with sevoflurane alone for anesthesia maintenance, dezocine for postoperative analgesia, FLACC scores, and esketamine exposure, were associated with ED. In conclusion, a near-anesthetic single-dose of esketamine for anesthesia induction may increase the incidence of ED in preschool children after minor surgery. The use of esketamine in preschool children for minor surgery should be noticed during clinical practice.

4.
Biomed Res Int ; 2022: 6236438, 2022.
Article in English | MEDLINE | ID: mdl-35958824

ABSTRACT

Traditional lung-protective ventilation strategies (LPVS) are currently used to reduce the incidence of postoperative pulmonary complications (PPCs), including low tidal volume (VT), positive end-expiratory pressure (PEEP), low inspiratory plateau pressure (Pplat), permissive hypercapnia, and recruitment maneuver (RM). However, a meta-analysis showed that high driving pressure was closely associated with the incidence of PPCs, but not with PEEP or VT, which led to the driving pressure-guided ventilation strategy. Some studies have proved that the driving pressure-guided ventilation strategy is superior to the traditional LPVS in reducing the incidence of PPCs. The purpose of this review is to present the current research progress and application of driving pressure-guided ventilation strategy.


Subject(s)
Lung , Positive-Pressure Respiration , Humans , Postoperative Complications , Respiration, Artificial , Tidal Volume
5.
Anal Chim Acta ; 1197: 339489, 2022 Mar 08.
Article in English | MEDLINE | ID: mdl-35168724

ABSTRACT

High concentrations of redox substances in the solution may cause severe electrode potential drift, resulting in the inaccuracy of in situ measurements. Sulfide anion, a highly reductive substance, is the killer of all metal oxide electrodes because of its small size and strong surface activity. We first proposed to use SPEEK (SP) with silica-stabilized imidazole-type ionic liquid (ImIL) to fabricate a composite film (SP/SiOx/ImIL) to achieve a high anti-interference ability for metal electrodes. The composite film was especially designed to address the interference caused by sulfide anions and other small-sized anions (i.e., I-, F- and ascorbic acid). The reduced proton conductivity was restored by introducing ImIL into SPEEK matrix. Open circuit potential tests showed that the potential of the SP/SiOx/ImIL modified IrOx electrode fluctuated within 0.3 mV in 30 min continuous test at a concentration of 10-3 M Na2S, exhibiting good stability in moderately high sulfide solution. It also exhibited fast response and good reversibility. In addition, no potential drift was measured under other anions interferences. XPS survey verified that the Ir4+/Ir3+ ratio of the IrOx electrode did not change before and after application in sulfide-containing solution, indicating that the SP/SiOx/ImIL composite film has good anion isolation capacity.


Subject(s)
Ionic Liquids , Electrodes , Hydrogen-Ion Concentration , Oxides , Silicon Dioxide
6.
Bioengineered ; 13(2): 2346-2359, 2022 02.
Article in English | MEDLINE | ID: mdl-35034579

ABSTRACT

Mechanical ventilation can induce lung injury and exacerbate brain injury due to lung-brain interaction. The current study sought to investigate the mechanism of lung-brain interaction induced by mechanical ventilation and offer theoretical insight into the management of ventilator-induced brain injury. The experimental mice were assigned into the spontaneously breathing group and the mechanical ventilation group and injected with dopamine (DA) receptor antagonist haloperidol or P2Y1 receptor antagonist MRS2279 before ventilation. In vitro assay was conducted using lung epithelial cells MLE-12 hippocampal neuron cells and HT-22. Mouse recognition function and lung injury were examined. The condition and concentration of neurons in the hippocampus were observed. The levels of several inflammatory factors, DA, adenosine triphosphate (ATP), P2Y1R, and dysbindin-1 were detected. Mechanical ventilation induced lung and brain injury in mice, manifested in increased inflammatory factors in the bronchoalveolar lavage fluid and hippocampus, prolonged escape latency, and swimming distance and time in the target quadrant with a weakened concentration of neurons in the hippocampus. Our results presented elevated ATP and P2Y1R expressions in the mechanically ventilated mice and stretched MLE-12 cells. The mechanically ventilated mice and P2Y1 receptor activator MRS2365-treated HT-22 cells presented with elevated levels of DA and dysbindin-1. Inactivation of P2Y1 receptor in the hippocampus or blockage of DA receptor alleviated brain injury induced by mechanical ventilation in mice. To conclude, the current study elicited that lung injury induced by mechanical ventilation exacerbated brain injury in mice by increasing ATP production, activating the P2Y1 receptor, and thus promoting DA release.


Subject(s)
Adenosine Triphosphate/metabolism , Brain Injuries/metabolism , Brain/metabolism , Dopamine/metabolism , Lung/metabolism , Receptors, Purinergic P2Y1/metabolism , Ventilator-Induced Lung Injury/metabolism , Animals , Mice
7.
J Clin Neurosci ; 92: 89-97, 2021 Oct.
Article in English | MEDLINE | ID: mdl-34509269

ABSTRACT

The involvement of Dexmedetomidine (Dex) has been indicated in postoperative cognitive dysfunction (POCD), while the mechanism is not well characterized. This study estimated the mechanism of Dex in POCD. Rats were anesthetized with sevoflurane (SEV) to evoke POCD and then subjected to Morris water maze test to detect the cognitive and behavioral function. Then, the damage of hippocampus and cortex, and apoptosis and activity of neurons were examined. Microarray analysis was performed to screen out the differentially expressed microRNAs (miRs) in rats after Dex treatment. The cognitive and behavioral functions and neuronal activity of rats were detected after miR-129 antagomir injection. The target of miR-129 was predicted. The levels of TLR4 and NF-κB p65 in hippocampus and cortex were measured. Dex treatment alleviated SEV-induced behavior and cognitive impairments in rats, promoted neuronal activity and hindered neuronal apoptosis. After treatment with Dex, miR-129 expression was elevated in brain tissues, and the neuroprotection of Dex on POCD rats was partially annulled after injection of miR-129 antagomir. Furthermore, miR-129 targeted TLR4 and prevented the phosphorylation of NF-κB p65. In summary, Dex ameliorated SEV-induced POCD by elevating miR-129 and inhibiting TLR4 and NF-κB p65 phosphorylation. This study may shed new lights on POCD treatment.


Subject(s)
Cognitive Dysfunction , Dexmedetomidine , MicroRNAs , Postoperative Cognitive Complications , Animals , Cognitive Dysfunction/chemically induced , Cognitive Dysfunction/prevention & control , Rats , Sevoflurane/toxicity , Toll-Like Receptor 4/genetics
8.
BMC Anesthesiol ; 21(1): 101, 2021 04 05.
Article in English | MEDLINE | ID: mdl-33820541

ABSTRACT

BACKGROUND: This study explored the comparison of the thermal insulation effect of incubator to infusion thermometer in laparoscopic hysterectomy. METHODS: We assigned 75 patients enrolled in the study randomly to three groups: Group A: Used warming blanket; group B: Used warming blanket and infusion thermometer; group C: Used warming blanket and incubator. The nasopharyngeal temperature at different time points during the operation served as the primary outcome. RESULTS: The nasopharyngeal temperature of the infusion heating group was significantly higher than that of the incubator group 60 min from the beginning of surgery (T3): 36.10 ± 0.20 vs 35.81 ± 0.20 (P<0.001)90 min from the beginning of surgery (T4): 36.35 ± 0.20 vs 35.85 ± 0.17 (P<0.001). Besides, the nasopharyngeal temperature of the incubator group was significantly higher compared to that of the control group 60 min from the beginning of surgery (T3): 35.81 ± 0.20 vs 35.62 ± 0.18 (P<0.001); 90 min from the beginning of surgery (T4): 35.85 ± 0.17 vs 35.60 ± 0.17 (P<0.001). Regarding the wake-up time, that of the control group was significantly higher compared to the infusion heating group: 24 ± 4 vs 21 ± 4 (P = 0.004) and the incubator group: 24 ± 4 vs 22 ± 4 (P = 0.035). CONCLUSION: Warming blanket (38 °C) combined infusion thermometer (37 °C) provides better perioperative thermal insulation. Hospitals without an infusion thermometer can opt for an incubator as a substitute. TRIAL REGISTRATION: This trial was registered with ChiCTR2000039162 , 20 October 2020.


Subject(s)
Body Temperature , Heating/instrumentation , Hypothermia/prevention & control , Nasopharynx , Adult , Aged , Female , Humans , Hysterectomy , Intraoperative Complications/prevention & control , Laparoscopy , Middle Aged , Postoperative Complications/prevention & control , Prospective Studies , Single-Blind Method
9.
Foods ; 10(2)2021 Feb 14.
Article in English | MEDLINE | ID: mdl-33672942

ABSTRACT

Hydrogen peroxide (H2O2) has been reported to be used for the illegal treatment of fishery products in order to obtain "fake" freshness. Residues of H2O2 in food may be of toxicology concern. In this study, a nonenzymatic sensor was developed based on Fe@PCN-224 metal-organic frameworks wrapped by Nafion to detect H2O2 concentration. The hybrid structure of Fe@PCN-224 was fabricated by incorporated free FeIII ions into the center of PCN-224, which was ultra-stable due to the strong interactions between Zr6 and the carboxyl group. Scanning electron spectroscopy images exhibited that Nafion sheets crossed together on the surface of Fe@PCN-224 nanoparticles to form a hierarchical and coherent structure for efficient electron transfer. Electrochemical investigations showed that the Fe@PCN-224/Nafion/GCE possessed good linearity from 2 to 13,000 µM (including four orders of magnitude), low detection limits (0.7 µM), high stability in continuous monitoring (current remained nearly stable over 2300 s) and in long-term measurement (current decreased 3.4% for 30 days). The prepared nanohybrid modified electrode was effectively applied to H2O2 detection in three different fishery products. The results were comparable to those measured using photometrical methods. The developed electrochemical method has a great potential in detecting the illegal management of fishery products with H2O2.

10.
Onco Targets Ther ; 13: 13131-13141, 2020.
Article in English | MEDLINE | ID: mdl-33380803

ABSTRACT

PURPOSE: Non-small cell lung cancer (NSCLC) accounts for more than 80% of lung cancer cases and remains the primary cause of cancer-related deaths worldwide. Fentanyl is a commonly utilized anesthetic during the process of tumor resection, and exhibits inhibitory effects on the progression of numerous cancer types, including pancreatic cancer, colorectal cancer and gastric cancer. However, the effects of fentanyl on the cell viability and invasion of NSCLC has not been investigated. Current study aimed to investigate the effects and the mechanisms underlying the effects of fentanyl on NSCLC. METHODS: The expression of µ-opioid receptor (MOR) was proved by flow cytometry. The expression of microRNA-331-3p (miR-331-3p) and histone deacetylase 5 (HDAC5) in NSCLC tissues and cell lines are evaluated by reverse transcription-quantitative PCR (RT-qPCR) and Western blot, respectively. Cell viability and invasion are measured by cell counting kit-8 (CCK-8) assay and transwell assay, respectively. The interaction between miR-331-3p and 3'-untranslated region (UTR) of HDAC5 is predicted by TargetScan 7.1 (http://www.targetscan.org/vert_71/), validated by dual luciferase assay, RT-qPCR and Western blot. RESULTS: There was lower miR-331-3p expression and higher HDAC5 expression in NSCLC cell lines A549 and CALU-1 compared with BEAS-2B, which was reversed by fentanyl administration. miR-331-3p targeted 3'-UTR of HDAC5 in NSCLC cell lines A549 and CALU-1. miR-331-3p inhibitor partially abrogated the inhibitory effects of fentanyl on NSCLC cell viability and invasion by targeting HDAC5. In addition, there was higher HDAC5 expression and lower miR-331-3p expression in tumor tissues which were isolated from patients with NSCLC compared to the adjacent normal tissues, and miR-331-3p was negatively correlated with HDAC5 in NSCLC tumor tissues. CONCLUSION: Fentanyl inhibits the viability and invasion of NSCLC cells by induction of miR-331-3p and reduction of HDAC5.

11.
Medicine (Baltimore) ; 99(22): e20424, 2020 05 29.
Article in English | MEDLINE | ID: mdl-32481441

ABSTRACT

PURPOSE: To evaluate the 95% effective dose of nalbuphine in patient-controlled intravenous analgesia (PCIA) by the sequential method and compare the analgesia efficacy with the equivalent dose of sufentanil on patients undergoing laparoscopic total hysterectomy. METHODS: In the first part, we defined a successful analgesia as the highest VAS ≤3 in 24 hours postoperatively. On the contrary, a failed analgesia was the highest VAS>3. According to the last patient's outcome, the next patients would be given an increase or decreased dose grade. This process ended up with 9 cross-over points. In the second part, 60 patients undergoing laparoscopic total hysterectomy were selected. They were randomly divided into 2 groups (n = 30 each group): receiving sufentanil 1.78 µg/kg (group S) and nalbuphine 1.78 mg/kg (group N). PCIA pump was given at the end of the operation with 5 mL bonus loading. The total amount of PCIA was 100 mL and programmed to deliver 0.5 mL each time with a lockout interval of 15 minutes and the background infusion amount of 2 mL/h. The VAS score and Ramsay score of were collected after the operation, the number of effective pressing times of PCIA were also recorded. Adverse reactions were documented in detail. RESULTS: The 95% effective dose of nalbuphine in PCIA on patients undergoing laparoscopic total hysterectomy was 1.78 mg/kg. There was no significant difference in VAS between the sufentanil group and the nalbuphine groups (P > .05), but the number of the use of PCIA in the group S was more than that in the group N obviously (P <.05). The group S has a lower ramsay sedation score than group N at every time point. (P <.05). The incidence of nausea and vomiting was not statistically significant differences between two groups in the first 24 hours after colonoscopy (P >  q .05). CONCLUSION: Nalbuphine 1.78 mg/kg in PCIA is recommended for the patients undergoing laparoscopic total hysterectomy. And nalbuphine is a reasonable alternative to sufentanil when used in PCIA.


Subject(s)
Analgesics, Opioid/administration & dosage , Hysterectomy , Laparoscopy , Nalbuphine/administration & dosage , Pain, Postoperative/drug therapy , Sufentanil/administration & dosage , Administration, Intravenous , Analgesia, Patient-Controlled , Cross-Over Studies , Dose-Response Relationship, Drug , Double-Blind Method , Female , Humans , Hysterectomy/methods , Laparoscopy/methods , Middle Aged
12.
Ann Transplant ; 21: 508-15, 2016 Aug 16.
Article in English | MEDLINE | ID: mdl-27527391

ABSTRACT

BACKGROUND Because of the restricted data available on patients with postoperative cognitive dysfunction (POCD) in orthotopic liver transplantation (OLT), the goal of our study was to determine the outcome of dexmedetomidine (DEX) on POCD and the mechanism operating in OLT patients. MATERIAL AND METHODS Our study included 80 patients randomly divided into 2 equal groups: the DEX group and the control group. In the DEX group, our patients received an initial dose of DEX at 1 µg/kg for 10 min followed by a continuous infusion at 0.3 µg/kg/h until the end of surgery. The control group received a saline treatment, and neurological tests were performed to assess the status of POCD. Serum level of b-amyloid protein (Aß) and neuronal microtubule-associated protein (Tau) were measured at designated time points: at pre-operation (T1), 0.5 h after the anhepatic phase (T2), 2 h after the reperfusion of the new liver (T3), at the completion of operation (T4), at day 1 (T5), and at day 7 (T6) after the operation. RESULTS The incidence of POCD was significantly reduced in the DEX group (P=0.017). The score from the neurological tests was significantly decreased in the control group after the operation, but no statistical difference was observed in the DEX group. The DEX groups demonstrated a lower level of ß-amyloid and Tau protein than those at the corresponding time points (T4~T6) in the control group (P<0.01). CONCLUSIONS Dexmedetomidine reduced the incidence of postoperative cognitive dysfunction in orthotopic liver transplantation patients. The decreased levels of b-amyloid and Tau protein may have contributed to this favorable outcome.


Subject(s)
Cognitive Dysfunction/prevention & control , Dexmedetomidine/pharmacology , Liver Transplantation/adverse effects , Postoperative Complications/prevention & control , Adolescent , Adrenergic alpha-2 Receptor Agonists/pharmacology , Adult , Amyloid beta-Peptides/blood , Cognitive Dysfunction/blood , Cognitive Dysfunction/etiology , Female , Humans , Male , Middle Aged , Neuropsychological Tests , Postoperative Complications/blood , Postoperative Complications/etiology , Risk Factors , Young Adult , tau Proteins/blood
13.
J Anesth ; 29(3): 346-351, 2015 Jun.
Article in English | MEDLINE | ID: mdl-25475993

ABSTRACT

PURPOSE: The aim of this study was to investigate the changes in oxidative stress and antioxidants in lung tissue under different tidal volume ventilation conditions. METHODS: Forty-eight male Wistar rats were randomized into four groups, namely, group C, the control group, which was not ventilated, and groups C1, C2 and C3, the treatment groups, which were ventilated for 2 h with tidal volumes of 8, 30 and 42 ml/kg, respectively. The right middle lobe was assayed for malondialdehyde (MDA), the right posterior lobe was assayed using Western blotting for Nrf2, GCLm and SrX1 and the left lobe was assayed for Nrf2, GCLm and SrX1 mRNA. RESULTS: The MDA levels were increased in the three treatment groups, with MDA levels highest in group C3 and lowest in group C1 (C3 > C2 > C1) (all P < 0.05). The mRNA expression of Nrf2, GCLm and SrX1 was highest in group C3 and lowest in group 1 (C3 > C2 > C1) (all P < 0.05). No significant difference was observed between group C1 and group C (P > 0.05). A Western blot analysis showed that Nrf2, GCLm and SrX1 expression was highest in group C3 and lowest in group C1 (C3 > C2 > C1) (all P < 0.05). No significant difference was observed between group C1 and group C (P > 0.05). CONCLUSIONS: Oxidative stress and antioxidant enzyme levels in the lungs of rats were positively associated with the tidal volumes of mechanical ventilation, suggesting that higher tidal volumes cause more severe oxidative stress and increased antioxidant responses.


Subject(s)
Antioxidants/metabolism , Lung/metabolism , Oxidative Stress/physiology , Respiration, Artificial/methods , Animals , Male , Malondialdehyde/metabolism , Rats , Rats, Wistar , Tidal Volume/physiology
14.
Tumour Biol ; 35(7): 7097-103, 2014 Jul.
Article in English | MEDLINE | ID: mdl-24760274

ABSTRACT

Recent studies have shown that Beclin 1, a key regulator of autophagic process, is frequently downregulated and may serve as an independent prognostic biomarker for nonsmall cell lung cancer. However, the molecular mechanisms underlying its downregulation remain poorly understood. The signal transducer and activator of transcription 3 (Stat3) is a transcription factor which plays a crucial role for multiple tumor growth and progression. Here, we demonstrate that Beclin 1 is a direct transcriptional target of Stat3 in lung cancer cells. Interleukin-6 (IL-6) treatment or transfection of a constitutively activated Stat3 in AGS and NCI-H1650 cells inhibited Beclin 1 expression. At the molecular level, we further revealed that Stat3 could directly bind to the promoter region of Beclin 1 and repressed its transcription through recruiting histone deacetylase 3 (HDAC3). Collectively, our results suggest that the activated Stat3 may represent an important mechanism for Beclin 1 downregulation in nonsmall cell lung cancer development.


Subject(s)
Apoptosis Regulatory Proteins/biosynthesis , Carcinoma, Non-Small-Cell Lung/genetics , Histone Deacetylases/metabolism , Membrane Proteins/biosynthesis , STAT3 Transcription Factor/metabolism , Apoptosis Regulatory Proteins/genetics , Beclin-1 , Carcinoma, Non-Small-Cell Lung/pathology , Cell Line, Tumor , Gene Expression Regulation, Neoplastic , Histone Deacetylases/genetics , Humans , Interleukin-6/administration & dosage , Interleukin-6/genetics , Membrane Proteins/genetics , Promoter Regions, Genetic , STAT3 Transcription Factor/genetics , Signal Transduction
15.
FEBS Lett ; 587(9): 1359-65, 2013 May 02.
Article in English | MEDLINE | ID: mdl-23507140

ABSTRACT

MicroRNAs (miRNA) play an important role in tumorigenesis, proliferation, and differentiation. Altered miRNA expression in cancer indicates that miRNAs can function as tumor suppressors or oncogenes. MiR-449c downregulation in non-small cell lung cancer (NSCLC) compared with normal lung tissues was investigated in this study. NSCLC cell proliferation and invasion assays indicate that transfection of miR-449c expression plasmid inhibits the proliferation and invasion ability of NCI-H23 and NCI-H838 cells. In addition, miR-449c overexpression could suppress tumor growth in vivo. Morever, c-Myc was identified as a direct target gene of miR-449c. These findings clearly suggest that miR-449c downregulation and c-Myc amplification may be involved in the development of NSCLC.


Subject(s)
Carcinoma, Non-Small-Cell Lung/pathology , Disease Progression , Lung Neoplasms/pathology , MicroRNAs/genetics , MicroRNAs/metabolism , Proto-Oncogene Proteins c-myc/genetics , Animals , Base Sequence , Carcinoma, Non-Small-Cell Lung/genetics , Cell Line, Tumor , Cell Proliferation , Cell Transformation, Neoplastic , Down-Regulation/genetics , Gene Expression Regulation, Neoplastic , Humans , Lung Neoplasms/genetics , Mice , Neoplasm Invasiveness
16.
Microbiology (Reading) ; 158(Pt 5): 1350-1358, 2012 May.
Article in English | MEDLINE | ID: mdl-22343352

ABSTRACT

Pyruvate dehydrogenase (PDH) of Escherichia coli is inhibited by NADH. This inhibition is partially reversed by mutational alteration of the dihydrolipoamide dehydrogenase (LPD) component of the PDH complex (E354K or H322Y). Such a mutation in lpd led to a PDH complex that was functional in an anaerobic culture as seen by restoration of anaerobic growth of a pflB, ldhA double mutant of E. coli utilizing a PDH- and alcohol dehydrogenase-dependent homoethanol fermentation pathway. The glutamate at position 354 in LPD was systematically changed to all of the other natural amino acids to evaluate the physiological consequences. These amino acid replacements did not affect the PDH-dependent aerobic growth. With the exception of E354M, all changes also restored PDH-dependent anaerobic growth of and fermentation by an ldhA, pflB double mutant. The PDH complex with an LPD alteration E354G, E354P or E354W had an approximately 20-fold increase in the apparent K(i) for NADH compared with the native complex. The apparent K(m) for pyruvate or NAD(+) for the mutated forms of PDH was not significantly different from that of the native enzyme. A structural model of LPD suggests that the amino acid at position 354 could influence movement of NADH from its binding site to the surface. These results indicate that glutamate at position 354 plays a structural role in establishing the NADH sensitivity of LPD and the PDH complex by restricting movement of the product/substrate NADH, although this amino acid is not directly associated with NAD(H) binding.


Subject(s)
Dihydrolipoamide Dehydrogenase/genetics , Escherichia coli Proteins/genetics , Escherichia coli/enzymology , NAD/metabolism , Pyruvate Dehydrogenase Complex/metabolism , Amino Acid Substitution , Dihydrolipoamide Dehydrogenase/metabolism , Escherichia coli/genetics , Escherichia coli/growth & development , Escherichia coli Proteins/metabolism , Ethanol/metabolism , Fermentation , Glutamic Acid/genetics , Models, Molecular , Mutagenesis, Site-Directed , Pyruvate Dehydrogenase Complex/genetics , Pyruvic Acid/metabolism
17.
J Anesth ; 25(6): 860-3, 2011 Dec.
Article in English | MEDLINE | ID: mdl-21935685

ABSTRACT

PURPOSE: To evaluate the suppressive effect of intravenous dezocine on fentanyl-induced cough during the induction of general anesthesia. METHODS: A total of 120 patients, American Society of Anesthesiologists (ASA) physical status I-II, were randomized into two equally sized groups (n = 60). These two groups were given either intravenous dezocine 0.1 mg/kg or a matching placebo (equal volume of 0.9% saline) 10 min before the induction of general anesthesia. Patients were induced with midazolam 0.1 mg/kg, fentanyl 5 µg/kg, propofol 1-1.5 mg/kg, and suxamethonium 1.5 mg/kg. The injection time of fentanyl was less than 2 s in all patients. The occurrence of cough was recorded 2 min after fentanyl bolus. RESULTS: No patient in the dezocine group had cough, and 42 patients in the control group had cough. This difference was statistically different between these two groups (P = 0.000). CONCLUSION: These results demonstrate that intravenous dezocine 0.1 mg/kg 10 min prior to induction was effective in suppressing fentanyl-induced cough in our patients.


Subject(s)
Anesthetics, Intravenous/adverse effects , Bridged Bicyclo Compounds, Heterocyclic/therapeutic use , Cough/chemically induced , Cough/drug therapy , Fentanyl/adverse effects , Tetrahydronaphthalenes/therapeutic use , Anesthesia, General/methods , Anesthetics, Intravenous/administration & dosage , Double-Blind Method , Drug Interactions , Female , Fentanyl/administration & dosage , Humans , Male , Middle Aged
18.
Microb Pathog ; 46(5): 266-72, 2009 May.
Article in English | MEDLINE | ID: mdl-19232388

ABSTRACT

Escherichia coli O157:H7 is an intestine-inhabiting bacterium associated with many severe disease outbreaks worldwide. It may enter the soil environment with the excreta of infected animals (including horses, cattle and chickens) and human. Earthworms are able to protect themselves against invading pathogens due to their efficient innate defense system. To better understand the mechanisms earthworms (Eisenia fetida) utilize to defend and eliminate Escherichia coli O157:H7, we examined the changes in the growth rate, as well as antioxidant and antimicrobial functions of earthworms in response to various concentrations of Escherichia coli O157:H7 in an artificial soil. Our results show that earthworms can inhibit the growth of Escherichia coli O157:H7. Upon exposure to Escherichia coli O157:H7 from 0 d to 24 d, coelomic cytolytic factor (CCF) in earthworms is induced, the reactive oxygen species (ROSs) and superoxide dismutase (SOD) are also elevated. Under lower bacterial concentrations (10(5)-10(6)CFU g(-1)), these ROSs can be rapidly scavenged by superoxide dismutase (SOD) to avoid peroxidation damage, but when the bacterial concentrations are high (10(7)-10(8)CFU g(-1)), excess amount of ROSs then cause accumulation of lipid peroxidation molecular malondialdehyde (MDA). In addition, exposure to Escherichia coli O157:H7 can induce the gene expression of antimicrobial peptide lumbricin I in the tissues of the earthworms. In conclusion, antioxidant systems and antimicrobial immune function may play important roles in the defense of the earthworms Eisenia fetida against Escherichia coli O157:H7.


Subject(s)
Escherichia coli O157/physiology , Oligochaeta/growth & development , Oligochaeta/microbiology , Soil Microbiology , Animals , Lectins/metabolism , Oligochaeta/metabolism , Peptides/metabolism , Reactive Oxygen Species/metabolism
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