SAR and QSAR models of cyclooxygenase-1 (COX-1) inhibitors

Cyclooxygenase-1 (COX-1) is one isoform of COX, and it is a main target of nonsteroidal anti-inflammatory drugs (NSAIDs). It is important to develop efficient and selective COX-1 inhibitors. In this work, 12 classification models for 1530 cyclooxygenase-1 (COX-1) inhibitors were built by support vector machine (SVM), decision tree (DT) and random forest (RF) methods. The best classification model (model 1A) was built by SVM with MACCS fingerprints. The classification accuracies for the training and test sets were 99.67% and 97.39%, respectively. The Matthews correlation coefficient (MCC) of the test set was 0.94. We also divided the 1530 COX-1 inhibitors into nine subsets according to their different scaffolds using Kohonen's self-organizing map (SOM). In addition, six quantitative structure-activity relationship (QSAR) models for 181 COX-1 inhibitors whose IC₅₀ were measured by enzyme immunoassay were built by multiple linear regression (MLR) and SVM. The best QSAR model (model 5A) was built by SVM with CORINA Symphony descriptors. The correlation coefficients of the training and test sets are 0.93 and 0.84, respectively. The models built in this study can be obtained from the authors.

Clofazimine improves clinical outcomes in multidrug-resistant tuberculosis: a randomized controlled trial

OBJECTIVES

We carried out a randomized multicentre study in China to investigate whether the clofazimine would improve the efficacy of the standardized regimen in patients with multidrug-resistant tuberculosis (MDR-TB).

METHODS

Patients with MDR-TB managed in 17 TB specialist hospitals in China between September 2009 and September 2011 were randomly assigned to the treatment groups at enrolment. In the intervention group, 100 mg clofazimine per day was added to the standardized regimen. The primary outcome was the proportion of patients with successful outcomes.

RESULTS

From the 156 patients that were screened, 74 were assigned to the control group and 66 to the clofazimine group. Of the 66 cases analysed for clinical outcome in the clofazimine group, 36 patients were cured, and seven completed treatment, yielding a favourable outcome rate of 65.1%. The proportion of patients with favourable outcomes receiving the control regimen was 47.3% (35/74), which was significantly lower than that in the clofazimine group (p 0.034, relative risk 0.661, 95% CI 0.243-0.949).

CONCLUSIONS

The addition of clofazimine to the standard regimen improved the treatment of MDR-TB.

IL6 derived from cancer-associated fibroblasts promotes chemoresistance via CXCR7 in esophageal squamous cell carcinoma

Various factors and cellular components in the tumor microenvironment are key drivers associated with drug resistance in many cancers. Here, we analyzed the factors and molecular mechanisms involved in chemoresistance in patients with esophageal squamous cell carcinoma (ESCC). We found that interleukin 6 (IL6) derived mainly from cancer-associated fibroblasts played the most important role in chemoresistance by upregulating C-X-C motif chemokine receptor 7 (CXCR7) expression through signal transducer and activator of transcription 3/nuclear factor-κB pathway. CXCR7 knockdown resulted in the inhibition of IL6-induced proliferation and chemoresistance. In addition, CXCR7 silencing significantly decreased gene expression associated with stemness, chemoresistance and epithelial-mesenchymal transition and suppressed the proliferation ability of ESCC cells in three-dimensional culture systems and angiogenesis assay. In clinical samples, ESCC patients with high expression of CXCR7 and IL6 presented a significantly worse overall survival and progression-free survival upon receiving cisplatin after operation. These results suggest that the IL6-CXCR7 axis may provide a promising target for the treatment of ESCC.

Age-related reduction of dermal fibroblast size upregulates multiple matrix metalloproteinases as observed in aged human skin in vivo

BACKGROUND

Fragmentation of collagen fibrils, the major structure protein in skin, is a hallmark of dermal ageing. Matrix metalloproteinases (MMPs) are largely responsible for the fragmentation of collagen fibrils.

OBJECTIVES

To quantify gene expression of all 23 known mammalian MMPs in sun-protected young and aged human skin in vivo and to investigate the potential mechanism underlying age-related alteration of multiple MMPs.

METHODS

MMP mRNA expression levels and MMP activity in sun-protected young and aged human skin in vivo were determined by real-time reverse transcription polymerase chain reaction (RT-PCR) and in situ zymography, respectively. The relative contributions to elevated MMPs in epidermis and dermis were quantified by laser capture microdissection coupled real-time RT-PCR. Dermal fibroblast morphology and collagen fibril fragmentation in human skin in vivo were assessed by second-harmonic generation microscopy and atomic force microscopy, respectively. In vitro cell morphology was assessed by CellTracker® fluorescent dye (Molecular Probes, Eugene, OR, U.S.A.) and phalloidin staining. Protein levels were determined by ProteinSimple capillary electrophoresis immunoassay (ProteinSimple, Santa Clare, CA, U.S.A.).

RESULTS

Multiple MMPs are elevated in aged human skin dermis. Increased MMP activity and collagen fibril fragmentation were observed in aged skin dermis. As dermal fibroblasts are the major MMP-producing cells in the dermis, reduction of dermal fibroblast size, which is observed in aged human skin, contributes to the elevation of age-related multiple MMPs. Reduction of fibroblast size upregulates c-Jun/c-Fos and activates AP-1.

CONCLUSIONS

Combined actions of the wide variety of MMPs that are constitutively elevated in aged dermis may be involved in the progressive degradation of dermal collagen fibrils. Age-related elevations of multiple MMPs are likely to be a result of the reduction of fibroblast size via activation of AP-1.

Ribonucleotide reductase represents a novel therapeutic target in primary effusion lymphoma

Primary effusion lymphoma (PEL) is a highly aggressive B-cell malignancy that is closely associated with one of oncogenic viruses infection, Kaposi's sarcoma-associated herpesvirus (KSHV). PEL prognosis is poor and patients barely survive more than 6 months even following active chemotherapy interventions. There is therefore an urgent need to discover more effective targets for PEL management. We recently found that the ribonucleotide reductase (RR) subunit M2 is potentially regulated by the key oncogenic HGF/c-MET pathway in PEL (Dai et al., Blood. 2015;126(26):2821-31). In the current study, we set to investigate the role of RR in PEL pathogenesis and to evaluate its potential as a therapeutic target. We report that the RR inhibitor 3-AP actively induces PEL cell cycle arrest through inhibiting the activity of the NF-κB pathway. Using a xenograft model, we found that 3-AP effectively suppresses PEL progression in immunodeficient mice. Transcriptome analysis of 3-AP treated PEL cell lines reveals altered cellular genes, most of whose roles in PEL have not yet been reported. Taken together, we propose that RR and its signaling pathway may serve as novel actionable targets for PEL management.

The injury of serotonin on intestinal epithelium cell renewal of weaned diarrhoea mice

Diarrhoea is a common cause of death in children and weaned animals. Recent research has found that serotonin (5-HT) in the gastrointestinal tract plays an important role in regulating growth and the maintenance of mucosa, which protect against diarrhoea. To determine the influence of 5-HT on intestinal epithelium cell renewal under weaned stress diarrhoea, a weaned-stress diarrhoea mouse model was established with senna infusion (15 mL/Kg) via intragastric administration and stress restraint (SR). Mice with an increase in 5-HT were induced by intraperitoneal injection with citalopram hydrobromide (CH, 10 mg/Kg). The results demonstrated that compared with the control animals, diarrhoea appeared in weaned stress mice and the 5-HT content in the small intestine was significantly increased (P<0.05). Further, the caspase-3 cells and cells undergoing apoptosis in the small intestine were significantly increased, but the VH (villus height), V/C (villus height /crypt depth), and PCNA-positive rate significantly decreased. Compared with the control animals, CH increased the intestinal 5-HT content, caspase-3 cells and cells undergoing apoptosis but decreased the VH and V/C. Compared with both control and weaned stress animals, weaned stress animals that were pre-treated with CH showed higher 5-HT concentrations, positive caspase-3 cells and cells undergoing apoptosis but lower VH, V/C and PCNA-positive rate. In vitro, a low concentration of 5-HT inhibit, IEC-6 cell line apoptosis but a higher concentration of 5-HT promoted it. Therefore, weaned stress diarrhoea mice were accompanied by a 5-HT increase in the small intestine and vice versa, and the increase in 5-HT induced by CH caused diarrhoea. In brief, 5-HT and diarrhoea slowed the intestinal epithelium cell renewal and injured the abortion function and mucosal barrier by decreasing VH, V/C and proliferation and increasing epithelium cell apoptosis.

[The analysis of pattern visual evoked potential in obstructive sleep apnea syndrome]

OBJECTIVE

To objectively evaluate visual function by pattern visual evoked potential (PVEP) and its related factors in patients with obstructive sleep apnea syndrome (OSAS)without any ocular symptoms.

METHODS

Eighty-three newly diagnosed OSAS and 18 normal subjects were enrolled in the study. The OSAS patients were divided into mild (n=11), moderate(n=17) and severe (n=55) groups based on the apnea-hypopnea index(AHI). Before the polysomnography(PSG) test, all participants underwent a PVEP examination measuring the latency and amplitude of P100.

RESULTS

Compared to healthy controls, the latency of P100 was significantly increased in OSAS patients [controls group: 97(95-100) ms, mild OSAS group: 101(98-103) ms, moderate OSAS group: 101(98-105) ms, severe OSAS group: 105(101-108) ms, all P<0.05], and the amplitude of P100 was significantly reduced [controls group: 9(8-10) μV, mild OSAS group: 7(5-8) μV, moderate OSAS group: 6(5-7) μV, severe OSAS group: 6(4-7) μV, all P<0.05]. The severe group showed significantly longer latency of P100 when compared with mild and moderate groups(P<0.05). In the OSAS patients, univariate analysis showed that, the latency of P100 was correlated with ODI, T90, AHI, sleep efficiency, minimum SaO2, and mean SaO2, and the amplitude of P100 was statistically associated with sleep efficiency .But the stepwise multiple linear regression analysis revealed that only AHI was significantly correlated with the latency of P100 (r=0.275, P<0.01).

CONCLUSION

Abnormal PVEP was found in patients with OSAS without any clinical manifestations of the optic neuropathy. The dysfunction of optic nerve was significantly associated with AHI and sleep efficiency.

Cloning of Porcine Pituitary Tumor Transforming Gene 1 and Its Expression in Porcine Oocytes and Embryos

The maternal-to-embryonic transition (MET) is a complex process that occurs during early mammalian embryogenesis and is characterized by activation of the zygotic genome, initiation of embryonic transcription, and replacement of maternal mRNA with embryonic mRNA. The objective of this study was to reveal the temporal expression and localization patterns of PTTG1 during early porcine embryonic development and to establish a relationship between PTTG1 and the MET. To achieve this goal, reverse transcription-polymerase chain reaction (RT-PCR) was performed to clone porcine PTTG1. Subsequently, germinal vesicle (GV)- and metaphase II (MII)-stage oocytes, zygotes, 2-, 4-, and 8-cell-stage embryos, morulas, and blastocysts were produced in vitro and their gene expression was analyzed. The results revealed that the coding sequence of porcine PTTG1 is 609-bp in length and that it encodes a 202-aa polypeptide. Using qRT-PCR, PTTG1 mRNA expression was observed to be maintained at high levels in GV- and MII-stage oocytes. The transcript levels in oocytes were also significantly higher than those in embryos from the zygote to blastocyst stages. Immunohistochemical analyses revealed that porcine PTTG1 was primarily localized to the cytoplasm and partially localized to the nucleus. Furthermore, the PTTG1 protein levels in MII-stage oocytes and zygotes were significantly higher than those in embryos from the 2-cell to blastocyst stage. After fertilization, the level of this protein began to decrease gradually until the blastocyst stage. The results of our study suggest that porcine PTTG1 is a new candidate maternal effect gene (MEG) that may participate in the processes of oocyte maturation and zygotic genome activation during porcine embryogenesis.

[The expression of serum endoplasmic reticulum stress protein-78 in obstructive sleep apnea patients]

OBJECTIVE

This study aimed to detect serum level of glucose regulated protein 78(GRP78) in patients with obstructive sleep apnea(OSA) and explore the relationship between endoplasmic reticulum stress and the pathophysiology of OSA.

METHODS

A total of 91 patients with OSA were enrolled in this study, including 30 mild, 28 moderate and 33 severe. The other 27 obese subjects were of age, gender and BMI matched group. Eleven moderate or severe OSA patients were administrated with continuous positive airway pressure (CPAP) treatment for 24 hours. Polysomnography, apnea hypopnea index (AHI), lowest arterial oxygen saturation(SaO2) and percentage of time spent at SaO2 below 90% (SIT90) were measured before and after sleep. Serum GRP78 was measured by ELISA.

RESULTS

The expression of GRP78 in mild(3.42±0.97)μg/L, moderate(2.67±1.14)μg/L and severe(2.62±1.11)μg/L OSA groups was significantly higher than in control group(1.75±0.41)μg/L (P<0.05). The GRP78 level in mild OSA group was significantly higher than either moderate or severe OSA group (P<0.05). After 24 h treatment of CPAP, serum GRP78 level decreased significantly [(1.77±0.39)μg/L vs(2.84±0.39)μg/L; P<0.05].

CONCLUSIONS

Endoplasmic reticulum stress involves in the pathophysiology of patients with OSA. Higher GRP78 level in mild OSA patients suggests that endoplasmic reticulum related protein GRP 78 might rise then fall during exacerbation of OSA.

Periostin: a novel biomarker for chronic rhinosinusitis

Periostin: a novel biomarker for chronic rhinosinusitis.

OBJECTIVES

Rhinosinusitis is characterized by inflammation of the sinuses, resulting in particular symptoms. This study aims to investigate the feasibility of periostin as a biomarker for chronic rhinosinusitis.

METHODOLOGY

The mucosal tissues of the ethmoid sinus were sampled from 12 patients with chronic rhinosinusitis without nasal polyps (CRsNP) and 25 with chronic rhinosinusitis with nasal polyps (CRwNP). Inferior turbinate biopsy was performed in 15 patients with a deviation of the nasal septum (DNS). Immunohistochemical (IHC) staining was performed to assess the distribution of periostin. Quantitative reverse transcription-polymerase chain reaction (RT-PCR) was conducted to detect the expression of periostin mRNA in nasal tissue specimens. The serum concentration of periostin was measured using enzyme-linked immunosorbent assay (ELISA). Correlation analysis among periostin mRNA in nasal mucosa, IHC staining score of periostin, serum concentration of periostin and proportion of blood eosinophils was performed.

RESULTS

The serum concentration of periostin and the IHC staining score of nasal mucosa from CRSsNP and CRSwNP patients were significantly higher than those in DNS counterparts (both P <0.01). The levels of periostin mRNA in CRSsNP and CRSwNP patients were slightly increased, but did not significantly differ from that in the DNS group (both P >0.05). The IHC staining score and serum concentration of periostin were correlated with the proportion of eosinophils in blood (P<0.05 and P <0.0 1).

CONCLUSION

Periostin can be used as a novel biomarker for chronic rhinosinusitis, which provides a potential target for individualized therapy of chronic rhinosinusitis.

High-density interspecific genetic linkage mapping provides insights into genomic incompatibility between channel catfish and blue catfish

Catfish is the leading aquaculture species in the United States. The interspecific hybrid catfish produced by mating female channel catfish with male blue catfish outperform both of their parent species in a number of traits. However, mass production of the hybrids has been difficult because of reproductive isolation. Investigations of genome structure and organization of the hybrids provide insights into the genetic basis for maintenance of species divergence in the face of gene flow, thereby helping develop strategies for introgression and efficient production of the hybrids for aquaculture. In this study, we constructed a high-density genetic linkage map using the hybrid catfish system with the catfish 250K SNP array. A total of 26,238 SNPs were mapped to 29 linkage groups, with 12,776 unique marker positions. The linkage map spans approximately 3240 cM with an average intermarker distance of 0.25 cM. A fraction of markers (986 of 12,776) exhibited significant deviation from the expected Mendelian ratio of segregation, and they were clustered in major genomic blocks across 15 LGs, most notably LG9 and LG15. The distorted markers exhibited significant bias for maternal alleles among the backcross progenies, suggesting strong selection against the blue catfish alleles. The clustering of distorted markers within genomic blocks should lend insights into speciation as marked by incompatibilities between the two species. Such findings should also have profound implications for understanding the genomic evolution of closely related species as well as the introgression of hybrid production programs in aquaculture.

Overexpression of αCaMKII impairs behavioral flexibility and NMDAR-dependent long-term depression in the medial prefrontal cortex

The medial prefrontal cortex (mPFC) participates in the behavioral flexibility. As a major downstream molecule in the NMDA receptor signaling, alpha-Ca(2+)/calmodulin-dependent protein kinase II (αCaMKII) is crucial for hippocampal long-term potentiation (LTP) and hippocampus-related memory. However, the role of αCaMKII in mPFC-related behavioral flexibility and mPFC synaptic plasticity remains elusive. In the present study, using chemical-genetic approaches to temporally up-regulate αCaMKII activity, we found that αCaMKII-F89G transgenic mice exhibited impaired behavioral flexibility in Y-water maze arm reversal task. Notably, in vitro electrophysiological analysis showed normal basal synaptic transmission, LTP and depotentiation, but selectively impaired NMDAR-dependent long-term depression (LTD) in the mPFC of αCaMKII-F89G transgenic mice. In accordance with the deficit in NMDAR-dependent LTD, αCaMKII-F89G transgenic mice exhibited impaired AMPAR internalization during NMDAR-dependent chemical LTD expression in the mPFC. Furthermore, the above deficits in behavioral flexibility, NMDAR-dependent LTD and AMPAR internalization could all be reversed by 1-naphthylmethyl (NM)-PP1, a specific inhibitor of exogenous αCaMKII-F89G activity. Taken together, our results for the first time indicate that αCaMKII overexpression in the forebrain impairs behavioral flexibility and NMDAR-dependent LTD in the mPFC, and supports the notion that there is a close relationship between NMDAR-dependent LTD and behavioral flexibility.

The different effects of high-frequency stimulation of the nucleus accumbens shell and core on food consumption are possibly associated with different neural responses in the lateral hypothalamic area

Obesity may result from dysfunction of the reward system, especially in the nucleus accumbens (Acb). Based on this hypothesis, many researchers have tested the effect of high-frequency stimulation (HFS) of the Acb shell (Acb-Sh) and/or core (Acb-Co) on ingestive behaviors, but few studies have explored the possible mechanisms involved in the differences between the Acb-Sh and Acb-Co. The present study tested effects of HFS of the Acb-Sh and Acb-Co on high-fat food (HFF) consumption in rats after 24h of food deprivation. Microdialysis and electrophysiological experiments were carried out in awake rats to explore potential mechanisms. The results showed that the Acb-Sh decreased HFF consumption after food deprivation both during and post-HFS. However, HFS of the Acb-Co did not induce similar changes in food consumption. HFS of the Acb-Sh (Sh-HFS) induced an increase in GABA level in the lateral hypothalamic area (LHA) during both phases, whereas HFS of the Acb-Co (Co-HFS) did not exhibit similar effects. The electrophysiological experiment showed that nearly all the LHA neurons were inhibited by Sh-HFS, and the mean firing rate decreased significantly both during and post-HFS. In contrast, the mean firing rate of the LHA neurons did not exhibit clear changes during Co-HFS, although some individual neurons appeared to exhibit responses to Co-HFS. Considering all the data, we postulated that Sh-HFS, rather than Co-HFS, might inhibit palatable food consumption after food deprivation by decreasing the reward value of that food, which suggested that it might also disturb the process of developing obesity. The mechanisms involved in the different effects of Sh-HFS and Co-HFS on food consumption may be associated with different neural responses in the LHA. The Acb-Sh has abundant GABAergic projections to the LHA, whereas the Acb-Co has few or no GABAergic innervations to the LHA. Thus, neural activity in the LHA exhibits different responses to Sh-HFS and Co-HFS.

The effect of buffalo CD14 shRNA on the gene expression of TLR4 signal pathway in buffalo monocyte/macrophages

CD14 plays a crucial role in the inflammatory response to lipopolysaccharide (LPS), which interacts with TLR4 and MD-2 to enable cell activation, resulting in inflammation. Upstream inhibition of the inflammation pathway mediated by bacterial LPS, toll-like receptor 4 (TLR4) and cluster of differentiation antigen 14 (CD14) was proven to be an effective therapeutic approach for attenuating harmful immune activation. To explore the effect of CD14 downregulation on the expression of TLR4 signaling pathway-related genes after LPS stimulation in buffalo (Bubalus bubalis) monocyte/macrophages, effective CD14 shRNA sequences were screened using qRT-PCR and FACS analysis with buffalo CD14 shRNA lentiviral recombinant plasmids (pSicoRGFP-shRNA) and buffalo CD14 fusion expression plasmids (pDsRed-N1-buffalo CD14) co-transfected into HEK293T cells via liposomes. Of the tested shRNAs, shRNA-1041 revealed the highest knockdown efficiency (p < 0.01). When buffalo peripheral blood monocyte/macrophages were infected with shRNA-1041 lentivirus and stimulated with LPS, the expression of endogenous CD14 was significantly decreased by CD14 shRNA (p < 0.01), and the mRNA expression levels of TLR4, IL-6 and TNF-α were also significantly downregulated compared to the control groups (p < 0.01). These results demonstrated that the knockdown of endogenous CD14 had clear regulatory effects on the signal transduction of TLR4 after stimulation with LPS. These results may provide a better understanding of the molecular mechanisms of CD14 regulation in the development of several buffalo diseases.

ECMO support for right main bronchial disruption in multiple trauma patient with brain injury--a case report and literature review

Extracorporeal membrane oxygenation (ECMO) may offer life-saving treatment in severe pulmonary contusion or acute respiratory distress syndrome when conventional treatments have failed. However, because of the bleeding risk of systemic anticoagulation, ECMO should be performed only as a last resort in multiple trauma victims. Here, we report ECMO as a bridge for right main bronchus reconstruction and recovery of traumatic wet lung in a 31-year-old male multi-trauma patient with right main bronchial disruption, bilateral pulmonary contusion, cerebral contusion and long bone fracture. The patient was discharged without any obvious complication. ECMO support in a traumatic brain injured patient with severe hypoxemia caused by lung contusion and/or tracheal bronchus disruption is not an absolute contraindication.

Nuclear chemistry. Synthesis and detection of a seaborgium carbonyl complex

Experimental investigations of transactinoide elements provide benchmark results for chemical theory and probe the predictive power of trends in the periodic table. So far, in gas-phase chemical reactions, simple inorganic compounds with the transactinoide in its highest oxidation state have been synthesized. Single-atom production rates, short half-lives, and harsh experimental conditions limited the number of experimentally accessible compounds. We applied a gas-phase carbonylation technique previously tested on short-lived molybdenum (Mo) and tungsten (W) isotopes to the preparation of a carbonyl complex of seaborgium, the 106th element. The volatile seaborgium complex showed the same volatility and reactivity with a silicon dioxide surface as those of the hexacarbonyl complexes of the lighter homologs Mo and W. Comparison of the product's adsorption enthalpy with theoretical predictions and data for the lighter congeners supported a Sg(CO)6 formulation.

Generation and tomography of arbitrary optical qubits using transient collective atomic excitations

We demonstrate the preparation of heralded Fock-basis qubits (a|0〉+b|1〉) from transient collective spin excitations in a hot atomic vapor. The preparation event is heralded by Raman-scattered photons in a four-wave mixing process seeded by a weak coherent optical excitation. The amplitude and phase of the seed field allow arbitrary control over the qubit coefficients. The qubit state is characterized using balanced homodyne tomography.

Gas-phase chemistry of Mo, Ru, W, and Os metal carbonyl complexes

Metal carbonyl complexes were used for studying the gas-phase chemical behavior of Mo, Ru, W and Os isotopes with an on-line low temperature isothermal gas chromatography apparatus. Short-lived Mo and Ru isotopes were produced by a 252Cf spontaneous fission source. Short-lived nuclides of W and Os were produced using the heavy ion reactions 19F +159Tb and 165Ho, respectively. Short-lived products were thermalized in a recoil chamber filled with a gas mixture of helium and carbon monoxide. The carbonyls formed were then transported through capillaries to an isothermal chromatography column for study of the adsorption behavior as a function of temperature. On-line isothermal chromatography (IC) experiments on Teflon (PTFE) and quartz surfaces showed that short-lived isotopes of the listed elements can form carbonyl complexes which are very volatile and interact most likely in physical sorption processes. Deduced adsorption enthalpies of Mo and Ru carbonyls were − 38 ± 2 kJ/mol and − 36 ± 2 kJ/mol, respectively. These values are in good agreement with literature data, partly obtained with different chromatographic techniques. A validation of the applied Monte Carlo model to deduce adsorption enthalpies with Mo isotopes of different half-lives proved the validity of the underlying adsorption model. The investigations using a gas-jet system coupled to a heavy ion accelerator without any preseparator clearly showed the limitations of the approach. The He and CO gas mixture, which was directly added into the chamber, will result in decomposition of CO gas and produce some aerosol particles. After the experiment of 173W and 179Os in the heavy ion experiments, the Teflon column was covered by a yellowish deposit; the adsorption enthalpy of W and Os carbonyls could therefore not be properly deduced using Monte Carlo simulations.

Long-range ordered nanodomains of grafted electroactive molecules

We demonstrate the capability to build zero and one-dimensional electroactive molecular nanostructures ordered over a macroscopic scale and stable under ambient conditions. To realize these arrays, we use the selective grafting of functionalized thiols (juglon and terthiophene based) on a self-organized metallic template. The nanoscale patterning of the molecular conductance is demonstrated and analyzed by scanning tunneling spectroscopy. Finally, the influence of the nanostructuring on electro-chemical properties is measured, paving the way to an all-bottom-up fabrication of nanostructured templates for nanosciences.

Serotypes, genotypes and antimicrobial resistance patterns of human diarrhoeagenic Escherichia coli isolates circulating in southeastern China

Diarrhoeagenic Escherichia coli (DEC) infection is a major health problem in developing countries. The prevalence and characteristics of DEC have not been thoroughly investigated in China. Consecutive faecal specimens from outpatients with acute diarrhoea in nine sentinel hospitals in southeastern China were collected from July 2009 to June 2011. Bacterial and viral pathogens were detected by culture and RT-PCR, respectively. DEC isolates were further classified into five pathotypes using multiplex PCR. The O/H serotypes, sequence types (STs) and antimicrobial susceptibility profiles of the DEC isolates were determined. A total of 2466 faecal specimens were collected, from which 347 (14.1%) DEC isolates were isolated. DEC was the dominant bacterial pathogen detected. The DEC isolates included 217 EAEC, 62 ETEC, 52 EPEC, 14 STEC, one EIEC and one EAEC/ETEC. O45 (6.6%) was the predominant serotype. Genotypic analysis revealed that the major genotype was ST complex 10 (87, 25.6%). Isolates belonging to the serogroups or genotypes of O6, O25, O159, ST48, ST218, ST94 and ST1491 were highly susceptible to the majority of antimicrobials. In contrast, isolates belonging to O45, O15, O1, O169, ST38, ST226, ST69, ST31, ST93, ST394 and ST648 were highly resistant to the majority of antimicrobials. DEC accounted for the majority of bacterial pathogens causing acute diarrhoea in southeastern China, and it is therefore necessary to test for all DEC, not only the EHEC O157:H7. Some serogroups or genotypes of DEC were highly resistant to the majority of antimicrobials. DEC surveillance should be emphasized.

Directed growth of mixed self-assembled monolayers on a nanostructured template: a step toward the patterning of functional molecular domains

We report on the elaboration of networks of SAM domains. More precisely, we show the feasibility in making arrays of functionalized alkylthiol nanodomains bordered with an alkylthiol matrix. The several step process relies on the replication of a self-organized cobalt array grown on Au(111). The SAM process takes place in solution. The chemical affinity of thiol for gold leads to the selective grafting of molecules on the surface. After having removed the inorganic array, alkylthiol functionalized with a terthiophene unit is grafted in free gold areas. The efficiency of the replication of the initial template depends on the stability of the first SAM. We also investigate electronic tunnel transport through oligothiophene islands with the STM. The variation of the molecular contrast with bias voltage between the two molecular species indicates a potential resonant tunneling mechanism through the orbitals of the aromatic compound.

Search for supersymmetry in events with three leptons and missing transverse momentum in √[s]=7 TeV pp collisions with the ATLAS detector

A search for the weak production of charginos and neutralinos decaying to a final state with three leptons (electrons or muons) and missing transverse momentum is presented. The analysis uses 2.06 fb(-1) of √[s]=7 TeV proton-proton collision data delivered by the Large Hadron Collider and recorded with the ATLAS detector. Observations are consistent with standard model expectations in two signal regions that are either depleted or enriched in Z-boson decays. Upper limits at 95% confidence level are set in R-parity conserving phenomenological minimal supersymmetric and simplified models. For the simplified models, degenerate lightest chargino and next-to-lightest neutralino masses up to 300 GeV are excluded for mass differences from the lightest neutralino up to 300 GeV.

Denis RD, Stahl T, Stahlman J, Stamen R, Stanecka E, Stanek RW, Stanescu C, Stapnes S, Starchenko EA, Stark J, Staroba P, Starovoitov P, Staude A, Stavina P, Stavropoulos G, Steele G, Steinbach P, Steinberg P, Stekl I, Stelzer B, Stelzer HJ, Stelzer-Chilton O, Stenzel H, Stevenson K, Stewart GA, Stillings JA, Stockmanns T, Stockton MC, Stoerig K, Stoicea G, Stonjek S, Strachota P, Stradling AR, Straessner A, Strandberg J, Strandberg S, Strandlie A, Strang M, Strauss E, Strauss M, Strizenec P, Ströhmer R, Strom DM, Strong JA, Stroynowski R, Strube J, Stugu B, Stumer I, Stupak J, Sturm P, Soh DA, Su D, Subramania HS, Sugaya Y, Sugimoto T, Suhr C, Suita K, Suk M, Sulin VV, Sultansoy S, Sumida T, Sun X, Sundermann JE, Suruliz K, Susinno G, Sutton MR, Suzuki Y, Swedish S, Sykora I, Sykora T, Sánchez J, Ta D, Tackmann K, Taffard A, Tafirout R, Taga A, Taiblum N, Takahashi Y, Takai H, Takashima R, Takeda H, Takeshita T, Talby M, Talyshev A, Tamsett MC, Tanaka J, Tanaka R, Tanaka S, Tanaka S, Tani K, Tannoury N, Tapprogge S, Tardif D, Tarem S, Tarrade F, Tartarelli GF, Tas P, Tasevsky M, Tassi E, Tatarkhanov M, Tayalati Y, Taylor C, Taylor FE, Taylor GN, Taylor W, Teixeira Dias Castanheira M, Teixeira-Dias P, Temming KK, Ten Kate H, Teng PK, Terada S, Terashi K, Terron J, Terwort M, Testa M, Teuscher RJ, Tevlin CM, Therhaag J, Theveneaux-Pelzer T, Thioye M, Thoma S, Thomas JP, Thompson EN, Thompson PD, Thompson PD, Thompson RJ, Thompson AS, Thomson E, Thomson M, Thun RP, Tic T, Tikhomirov VO, Tikhonov YA, Timmermans CJWP, Tipton P, Tique Aires Viegas FJ, Tisserant S, Todorov T, Todorova-Nova S, Toggerson B, Tojo J, Tokár S, Tokunaga K, Tokushuku K, Tollefson K, Tomoto M, Tompkins L, Toms K, Tonazzo A, Tonoyan A, Topfel C, Topilin ND, Torchiani I, Torrence E, Torró Pastor E, Toth J, Touchard F, Tovey DR, Traynor D, Trefzger T, Treis J, Tremblet L, Tricoli A, Trigger IM, Trincaz-Duvoid S, Trinh TN, Tripiana MF, Trischuk W, Trivedi A, Trocmé B, Troncon C, Trottier-McDonald M, Trzupek A, Tsarouchas C, Tseng JCL, Tsiakiris M, Tsiareshka PV, Tsionou D, Tsipolitis G, Tsiskaridze V, Tskhadadze EG, Tsukerman II, Tsulaia V, Tsung JW, Tsuno S, Tsybychev D, Tua A, Tuggle JM, Turala M, Turecek D, Turk Cakir I, Turlay E, Turra R, Tuts PM, Twomey MS, Tykhonov A, Tylmad M, Tyndel M, Typaldos D, Tyrvainen H, Tzanakos G, Uchida K, Ueda I, Ueno R, Ugland M, Uhlenbrock M, Uhrmacher M, Ukegawa F, Unal G, Undrus A, Unel G, Unno Y, Urbaniec D, Urkovsky E, Urrejola P, Usai G, Uslenghi M, Vacavant L, Vacek V, Vachon B, Vahsen S, Valderanis C, Valenta J, Valente P, Valentinetti S, Valkar S, Valladolid Gallego E, Vallecorsa S, Valls Ferrer JA, van der Graaf H, van der Kraaij E, Van Der Leeuw R, van der Poel E, van der Ster D, Van Eijk B, van Eldik N, van Gemmeren P, van Vulpen I, Vandelli W, Vaniachine A, Vankov P, Vannucci F, Vari R, Varnes EW, Varouchas D, Vartapetian A, Varvell KE, Vassilakopoulos VI, Vazeille F, Vegni G, Veillet JJ, Veloso F, Veness R, Veneziano S, Ventura A, Ventura D, Venturi M, Venturi N, Vercesi V, Verducci M, Verkerke W, Vermeulen JC, Vest A, Vetterli MC, Vichou I, Vickey T, Viehhauser GHA, Viel S, Villa M, Villani EG, Villaplana Perez M, Vilucchi E, Vincter MG, Vinek E, Vinogradov VB, Virchaux M, Viret S, Virzi J, Vitale A, Vitells O, Viti M, Vivarelli I, Vives Vaque F, Vlachos S, Vlasak M, Vlasov N, Vogel A, Vokac P, Volpi G, Volpi M, Volpini G, von der Schmitt H, von Loeben J, von Radziewski H, von Toerne E, Vorobel V, Vorwerk V, Vos M, Voss R, Voss TT, Vossebeld JH, Vovenko AS, Vranjes N, Vranjes Milosavljevic M, Vrba V, Vreeswijk M, Vu Anh T, Vuillermet R, Vukotic I, Wagner W, Wagner P, Wahlen H, Wakabayashi J, Walbersloh J, Walch S, Walder J, Walker R, Walkowiak W, Wall R, Waller P, Wang C, Wang H, Wang J, Wang J, Wang R, Wang SM, Warburton A, Ward CP, Warsinsky M, Wastie R, Watkins PM, Watson AT, Watson MF, Watts G, Watts S, Waugh AT, Waugh BM, Weber J, Weber M, Weber MS, Weber P, Weidberg AR, Weigell P, Weingarten J, Weiser C, Wellenstein H, Wells PS, Wen M, Wenaus T, Wendler S, Weng Z, Wengler T, Wenig S, Wermes N, Werner M, Werner P, Werth M, Werthenbach U, Wessels M, Whalen K, Wheeler-Ellis SJ, White A, White MJ, White S, Whitehead SR, Whiteson D, Whittington D, Wicek F, Wicke D, Wickens FJ, Wiedenmann W, Wielers M, Wienemann P, Wiik-Fuchs LAM, Wijeratne PA, Wildauer A, Wildt MA, Wilhelm I, Wilkens HG, Will JZ, Williams E, Williams HH, Willis W, Willocq S, Wilson JA, Wilson MG, Wilson A, Wingerter-Seez I, Winkelmann S, Winklmeier F, Wittgen M, Wolter MW, Wolters H, Wooden G, Wosiek BK, Wotschack J, Woudstra MJ, Wraight K, Wright C, Wright D, Wrona B, Wu SL, Wu X, Wu Y, Wulf E, Wynne BM, Xaplanteris L, Xella S, Xie S, Xu C, Xu D, Yabsley B, Yamada M, Yamamoto A, Yamamoto K, Yamamoto S, Yamamura T, Yamaoka J, Yamazaki T, Yamazaki Y, Yan Z, Yang H, Yang UK, Yang Y, Yang Z, Yanush S, Yao WM, Yao Y, Yasu Y, Ybeles Smit GV, Ye J, Ye S, Yilmaz M, Yoosoofmiya R, Yorita K, Yoshida R, Young C, Youssef S, Yu D, Yu J, Yu J, Yuan L, Yurkewicz A, Zaidan R, Zaitsev AM, Zajacova Z, Zalite YK, Zanello L, Zarzhitsky P, Zaytsev A, Zeitnitz C, Zeller M, Zema PF, Zemla A, Zendler C, Zenin AV, Zenin O, Ženiš T, Zinonos Z, Zenz S, Zerwas D, Zevi della Porta G, Zhan Z, Zhang D, Zhang H, Zhang J, Zhang Q, Zhang X, Zhang Z, Zhao L, Zhao T, Zhao Z, Zhemchugov A, Zhong J, Zhou B, Zhou N, Zhou Y, Zhu CG, Zhu H, Zhu Y, Zhuang X, Zhuravlov V, Zieminska D, Zilka B, Zimmermann R, Zimmermann S, Zimmermann S, Ziolkowski M, Zitoun R, Živković L, Zmouchko VV, Zobernig G, Zoccoli A, Zolnierowski Y, Zsenei A, zur Nedden M, Zutshi V, Zwalinski L. Search for lepton flavour violation in the eμ continuum with the ATLAS detector in [Formula: see text]pp collisions at the LHC

This paper presents a search for the t-channel exchange of an R-parity violating scalar top quark ([Formula: see text]) in the e±μ∓ continuum using 2.1 fb-1 of data collected by the ATLAS detector in [Formula: see text]pp collisions at the Large Hadron Collider. Data are found to be consistent with the expectation from the Standard Model backgrounds. Limits on R-parity-violating couplings at 95 % C.L. are calculated as a function of the scalar top mass ([Formula: see text]). The upper limits on the production cross section for pp→eμX, through the t-channel exchange of a scalar top quark, ranges from 170 fb for [Formula: see text] to 30 fb for [Formula: see text].

Measurement of the ZZ production cross section and limits on anomalous neutral triple gauge couplings in proton-proton collisions at sqrt[s] = 7 TeV with the ATLAS detector

A measurement of the ZZ production cross section in proton-proton collisions at sqrt[s] = 7 TeV using data corresponding to an integrated luminosity of 1.02 fb(-1) recorded by the ATLAS experiment at the LHC is presented. Twelve events containing two Z boson candidates decaying to electrons and/or muons are observed, with an expected background of 0.3 ± 0.3(stat)(-0.3)(+0.4)(syst) events. The cross section measured in a phase-space region with good detector acceptance and for dilepton masses within the range 66 to 116 GeV is σ(ZZ → ℓ+ ℓ- ℓ+ ℓ-)(fid) = 19.4(-5.2)(+6.3)(stat)(-0.7)(+0.9)(syst) ± 0.7(lumi) fb. The resulting total cross section for on-shell ZZ production, σ(ZZ)(tot) = 8.5(-2.3)(+2.7)(stat)(-0.3)(+0.4)(syst) ± 0.3(lumi) pb, is consistent with the standard model expectation of 6.5(-0.2)(+0.3) pb calculated at the next-to-leading order in QCD. Limits on anomalous neutral triple gauge boson couplings are derived.

Post-Transcriptional Regulation by MicroRNA-21 and let-7a MicroRNA in Paediatric Cholesteatoma

This study investigated the role of microRNA-21 (miR-21) and let-7a microRNA in paediatric and adult cholesteatoma. Total RNA and protein were isolated from the cholesteatoma specimens and normal skin of 10 adults and 10 children. Levels of miR-21 and let-7a microRNA were assessed by real-time reverse transcription-polymerase chain reaction, and levels of phosphatase and tensin homologue (PTEN), programmed cell death 4 (PDCD4) and high mobility group AT-hook 2 (HMGA2) protein were assessed by Western blot analysis. Levels of miR-21 and let-7a microRNA were significantly higher in cholesteatoma tissue compared with normal skin, especially in paediatric patients. PTEN, PDCD4 and HMGA2 protein levels were significantly lower in paediatric versus adult cholesteatoma patients. It is possible that upregulation of miR-21 leads to higher tumour cell proliferation and invasion of cholesteatoma in children than adults, and the benign nature of cholesteatoma may be due to a balance between let-7a microRNA and miR-21. These data may help to identify targets for miRNA- and protein-based therapeutic interventions for the non-surgical or adjunctive treatment of cholesteatoma.

Cooperative roles for emmprin and LYVE-1 in the regulation of chemoresistance for primary effusion lymphoma

The Kaposi's sarcoma-associated herpesvirus is the causative agent of primary effusion lymphoma (PEL), for which cytotoxic chemotherapy represents the standard of care. The high mortality associated with PEL may be explained in part by resistance of these tumors to chemotherapy. The membrane-bound glycoprotein emmprin (CD147) enhances chemoresistance in tumors through effects on transporter expression, trafficking and interactions. Interactions between hyaluronan and hyaluronan receptors on the cell surface also facilitate emmprin-mediated chemoresistance. Whether emmprin or hyaluronan-receptor interactions regulate chemotherapeutic resistance for virus-associated malignancies is unknown. Using human PEL tumor cells, we found that PEL sensitivity to chemotherapy is directly proportional to expression of emmprin, the lymphatic vessel endothelial hyaluronan receptor-1 (LYVE-1) and a drug transporter known as the breast cancer resistance protein/ABCG2 (BCRP), and that emmprin, LYVE-1 and BCRP interact with each other and colocalize on the PEL cell surface. In addition, we found that emmprin induces chemoresistance in PEL cells through upregulation of BCRP expression, and RNA interference targeting of emmprin, LYVE-1 or BCRP enhances PEL cell apoptosis induced by chemotherapy. Finally, disruption of hyaluronan-receptor interactions using small hyaluronan oligosaccharides reduces expression of emmprin and BCRP while sensitizing PEL cells to chemotherapy. Collectively, these data support interdependent roles for emmprin, LYVE-1 and BCRP in chemotherapeutic resistance for PEL.

Part 5. Public health and air pollution in Asia (PAPA): a combined analysis of four studies of air pollution and mortality

BACKGROUND

In recent years, Asia has experienced rapid economic growth and a deteriorating environment caused by the increasing use of fossil fuels. Although the deleterious effects of air pollution from fossil-fuel combustion have been demonstrated in many Western nations, few comparable studies have been conducted in Asia. Time-series studies of daily mortality in Asian cities can contribute important new information to the existing body of knowledge about air pollution and health. Not only can these studies verify important health effects of air pollution in local regions in Asia, they can also help determine the relevance of existing air pollution studies to mortality and morbidity for policymaking and environmental controls. In addition, the studies can help identify factors that might modify associations between air pollution and health effects in various populations and environmental conditions. Collaborative multicity studies in Asia-especially when designed, conducted, and analyzed using a common protocol-will provide more robust air pollution effect estimates for the region as well as relevant, supportable estimates of local adverse health effects needed by environmental and public-health policymakers.

SPECIFIC OBJECTIVES

The Public Health and Air Pollution in Asia (PAPA*) project, sponsored by the Health Effects Institute, consisted of four studies designed to assess the effects of air pollution on mortality in four large Asian cities, namely Bangkok, in Thailand, and Hong Kong, Shanghai, and Wuhan, in China. In the PAPA project, a Common Protocol was developed based on methods developed and tested in NMMAPS, APHEA, and time-series studies in the literature to help ensure that the four studies could be compared with each other and with previous studies by following an established protocol. The Common Protocol (found at the end of this volume) is a set of prescriptive instructions developed for the studies and used by the investigators in each city. It is flexible enough to allow for adjustments in methods to optimize the fit of health-effects models to each city's data set. It provides the basis for generating reproducible results in each city and for meta-estimates from combined data. By establishing a common methodology, factors that might influence the differences in results from previous studies can more easily be explored. Administrative support was provided to ensure that the highest quality data were used in the analysis. It is anticipated that the PAPA results will contribute to the international scientific discussion of how to conduct and interpret time-series studies of air pollution and will stimulate the development of high-quality routine systems for recording daily deaths and hospital admissions for time-series analysis.

METHODS

Mortality data were retrieved from routine databases with underlying causes of death coded using the World Health Organization (WHO) International Classification of Diseases, 9th revision or 10th revision (ICD-9, ICD-10). Air quality measurements included nitrogen dioxide (NO2), sulfur dioxide (SO2), particulate matter with aerodynamic diameter < or = 10 microm (PM10), and ozone (O3) and were obtained from several fixed-site air monitoring stations that were located throughout the metropolitan areas of the four cities and that met the standards of procedures for quality assurance and quality control carried out by local government units in each city. Using the Common Protocol, an optimized core model was established for each city to assess the effects of each of the four air pollutants on daily mortality using generalized linear modeling with adjustments for time trend, seasonality, and other time-varying covariates by means of a natural-spline smoothing function. The models were adjusted to suit local situations by correcting for influenza activity, autocorrelation, and special weather conditions. Researchers in Hong Kong, for example, used influenza activity based on frequency of respiratory mortality; researchers in Hong Kong and Shanghai used autoregressive terms for daily outcomes at lag days; and researchers in Wuhan used additional smoothing for periods with extreme weather conditions.

RESULTS AND DISCUSSION

For mortality due to all natural (nonaccidental) causes at all ages, the effects of air pollutants per 10-microg/m3 increase in concentration was found to be higher in Bangkok than in the three Chinese cities, with the exception of the effect of NO2 in Wuhan. The magnitude of the effects for cardiovascular and respiratory mortality were generally higher than for all natural mortality at all ages. In addition, the effects associated with PM10 and O3 in all natural, cardiovascular; and respiratory mortality were found to be higher in Bangkok than in the three Chinese cities. The explanation for these three findings might be related to consistently higher daily mean temperatures in Bangkok, variations in average time spent outdoors by the susceptible populations, and the fact that less air conditioning is available and used in Bangkok than in the other cities. However, when pollutant concentrations were incorporated into the excess risk estimates through the use of interquartile range (IQR), the excess risk was more comparable across the four cities. We found that the increases in effects among older age groups were greater in Bangkok than in the other three cities. After excluding data on extremely high concentrations of PM10 in Bangkok, the effect estimate associated with PM10 concentrations decreased in Bangkok (suggesting a convex relationship between risk and PM10, where risk levels off at high concentrations) instead of increasing, as it did in the other cities. This leveling off of effect estimates at high concentrations might be related to differences in vulnerability and exposure of the population to air pollution as well as to the sources of the air pollutant. IMPLICATIONS OF THE STUDY: The PAPA project is the first coordinated Asian multicity air pollution study ever published; this signifies the beginning of an era of cooperation and collaboration in Asia, with the development of a common protocol for coordination, data management, and analysis. The results of the study demonstrated that air pollution in Asia is a significant public health burden, especially given the high concentrations of pollutants and high-density populations in major cities. When compared with the effect estimates reported in the research literature of North America and Western Europe, the study's effect estimates for PM10 were generally similar and the effect estimates for gaseous pollutants were relatively higher. In Bangkok, however, a tropical city where total exposures to outdoor pollution might be higher than in most other cities, the observed effects were greater than those reported in the previous (i.e., Western) studies. In general, the results suggested that, even though social and environmental conditions across Asia might vary, it is still generally appropriate to apply to Asia the effect estimates for other health outcomes from previous studies in the West. The results also strongly support the adoption of the global air quality guidelines recently announced by WHO.

Early exposure of high-dose interleukin-4 to tumor stroma reverses myeloid cell-mediated T-cell suppression

Myeloid-derived suppressor cells (MDSCs) inhibit T-cell activity and promote tumor growth in tumor-bearing hosts. We sought to determine how to prevent the generation of these cells and modulate anti-tumor immunity at different times during tumor growth. Interleukin-4 (IL-4), a cytokine closely associated with the differentiation of myeloid cells, was expressed locally at the tumor site with its dose and expression time tightly regulated by a tet-off system. Early exposure of high-dose IL-4 to the tumor stromal cells effectively prevented the generation of myeloid suppressor cells and led to a T-cell-mediated tumor rejection. However, IL-4 had no effect a few days after tumor growth, when myeloid suppressor cells had been generated and T cells were tolerized. Importantly, coinoculation of IL-4 receptor (IL-4R)-deficient tumor cells with IL-4R competent, but not IL-4R-deficient myeloid cells led to IL-4-mediated tumor regression in IL-4R-deficient mice, indicating that IL-4 acts directly on myeloid cells. These results show a novel way to prevent T cells from MDSC-induced suppression, with important indications for cancer therapy.

Zebrafish (Danio rerio) gill neuroepithelial cells are sensitive chemoreceptors for environmental CO2

Adult zebrafish exhibit hyperventilatory responses to absolute environmental CO(2) levels as low as 0.13% ( mmHg), more than an order of magnitude lower than the typical arterial levels (40 mmHg) monitored by the mammalian carotid body. The sensory basis underlying the ability of fish to detect and respond to low ambient CO(2) levels is not clear. Here, we show that the neuroepithelial cells (NECs) of the zebrafish gill, known to sense O(2) levels, also respond to low levels of CO(2). An electrophysiological characterization of this response using both current and voltage clamp protocols revealed that for increasing CO(2) levels, a background K(+) channel was inhibited, resulting in a partial pressure-dependent depolarization of the NEC. To elucidate the signalling pathway underlying K(+) channel inhibition, we used immunocytochemistry to show that these NECs express carbonic anhydrase (CA), an enzyme involved in CO(2) sensing in the mammalian carotid body. Further, the NEC response to CO(2) (magnitude of membrane depolarization and time required to achieve maximal response), under conditions of constant pH, was reduced by 50% by the CA-inhibitor acetazolamide. This suggests that the CO(2) detection mechanism involves an intracellular sensor that is responsive to the rate of acidification associated with the hydration of CO(2) and which does not require a change of extracellular pH. Because some cells that were responsive to increasing also responded to hypoxia with membrane depolarization, the present results demonstrate that a subset of the NECs in the zebrafish gill are bimodal sensors of CO(2) and O(2).