Serum paraoxonase, arylesterase activities and oxidative status in patients with insomnia

AIM

The aim of this study was to investigate serum paraoxonase (PON) activity, arylesterase (ARE) activity, total antioxidant status (TAS), total oxidant status (TOS) and oxidative stress index (OSI) levels in patients with insomnia and to determine whether there was a relationship between oxidative stress and insomnia.

PATIENTS AND METHODS

A total of 29 insomniacs and 25 healthy controls were recruited in this study. Serum PON and ARE activities, TAS and TOS level were determined, and OSI were calculated.

RESULTS

Patients with insomnia had lower PON and ARE activities as compared to healthy controls (PON: 82.0±30.0 U/L vs. 193.5±58.4 U/L, p < 0.001; ARE: 143.0±26.7 U/L vs. 175.0±27.1 U/L, p < 0.001; respectively). Serum TAS was lower, while TOS and OSI were higher in the insomnia group than in the control group (TAS: 1.13±0.29 mmol Trolox equivalent/L vs. 1.70±0.35 mmol Trolox equivalent /L, p < 0.001; TOS: 18.68±5.03 µmol H2O2 equivalent/L vs. 10.92±2.21 µmol H2O2 equivalent/L, p < 0.001; OSI: 1.76±0.74 vs. 0.68±0.23, p < 0.001; respectively).

CONCLUSIONS

Patients with insomnia have increased systemic oxidative stress and reduced levels of serum antioxidant enzymes. Oxidative stress appears to be an underlying condition associated with insomnia.

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.

Dopamine D3 receptors regulate reconsolidation of cocaine memory

Memories of learned associations between the rewarding properties of drugs of abuse and environmental cues contribute to craving and relapse in humans. Disruption of reconsolidation dampens or even erases previous memories. Dopamine (DA) mediates the acquisition of reward memory and drugs of abuse can pathologically change related neuronal circuits in the mesolimbic DA system. Previous studies showed that DA D3 receptors are involved in cocaine-conditioned place preference (CPP) and reinstatement of cocaine-seeking behavior. However, the role of D3 receptors in reconsolidation of cocaine-induced reward memory remains unclear. In the present study, we combined genetic and pharmacological approaches to investigate the role of D3 receptors in reconsolidation of cocaine-induced CPP. We found that the mutation of the D3 receptor gene weakened reconsolidation of cocaine-induced CPP in mice triggered by a 3-min (min) retrieval. Furthermore, treatment of a selective D3 receptor antagonist PG01037 immediately following the 3-min retrieval disrupted reconsolidation of cocaine-induced CPP in wild-type mice and such disruption remained at least 1 week after the 3-min retrieval. These results suggest that D3 receptors play a key role in reconsolidation of cocaine-induced CPP in mice, and that pharmacological blockade of these receptors may be therapeutic for the treatment of cocaine craving and relapse in clinical settings.

Downregulation of Mcl-1 through inhibition of translation contributes to benzyl isothiocyanate-induced cell cycle arrest and apoptosis in human leukemia cells

Benzyl isothiocyanate (BITC) is one of the compounds of ITCs' family that has attracted a great deal of interest because of its ability to exhibit anticancer activity. In this study, we investigated the effects of BITC on cell cycle arrest and apoptosis in human leukemia cell lines, primary leukemia cells, and nude mice Jurkat xenograft. Exposure of Jurkat cells to BITC resulted in dose- and time-dependent increase in apoptosis, caspase activation, cytochrome c release, nuclear apoptosis-inducing factor (AIF) accumulation, Bcl2-associated X protein (Bax) translocation, and myeloid cell leukemia-1 (Mcl-1) downregulation. Treatment with these cells also resulted in cell cycle arrest at the G2/M phase. The G2/M-arrested cells are more sensitive to undergoing Mcl-1 downregulation and apoptosis mediated by BITC. BITC downregulates Mcl-1 expression through inhibition of translation, rather than through a transcriptional, post-translational, or caspase-dependent mechanism. Dephosphorylation of eukaryotic initiation factor 4G could contribute to the inhibition of Mcl-1 translation mediated by BITC. Furthermore, ectopic expression of Mcl-1 substantially attenuates BITC-mediated lethality in these cells, whereas knockdown of Mcl-1 through small interfering RNA significantly enhances BITC-mediated lethality. Finally, administration of BITC markedly inhibited tumor growth and induced apoptosis in Jurkat xenograft model in association with the downregulation of Mcl-1. Taken together, these findings represent a novel mechanism by which agents targeting Mcl-1 potentiate BITC lethality in transformed and primary human leukemia cells and inhibitory activity of tumor growth of Jurkat xenograft model.

Cryopreservation of Kalopanax septemlobus embryogenic callus using vitrification and droplet-vitrification

A cryopreservation protocol has been developed for embryogenic callus cultures of castor aralia (Kalopanax septemlobus), a deciduous tree which is widely used in oriental medicine and in landscape design. Three preculture treatments, four loading and six vitrification solutions were tested in a vitrification procedure. Preculture of embryogenic callus (EC) with high sucrose concentrations (up to 0.7 M) showed no effect on regrowth after cryopreservation. Loading for 20 min at ambient temperature improved regrowth of cryopreserved EC by 70-75 percent compared with non-loaded samples, regardless of the composition of the loading solution. Among vitrification solutions, the highest regrowth of 95-100 percent after cryopreservation was obtained after incubation of EC in a vitrification solution A3-80 percent comprising (w/v) 33.3 percent glycerol + 13.3 percent DMSO + 13.3 percent EG + 20.1 percent sucrose for 40 min at 0°C. Profiling of crystallization and recrystallization events using differential scanning calorimetry (DSC) confirmed that freezing injury was minimized in samples after loading and cryoprotection with this vitrification solution. Unlike many other papers, the droplet-vitrification protocol did not produce higher post-cryopreservation regrowth of Kalopanax EC, compared with the vitrification procedure. When samples are sufficiently cryoprotected during VS treatment, vitrification using cryovials may be preferred, since droplet-vitrification is more complex and requires skilled personnel. Cryopreserved callus grew rapidly and produced numerous somatic embryos, which developed similarly to embryos obtained from non-cryopreserved samples.

Real-time PCR and Amplified MTD® for rapid detection of Mycobacterium tuberculosis in pulmonary specimens

SETTING

Patients with suspected pulmonary tuberculosis (PTB) in the First Affiliated Hospital, College of Medicine, Zhejiang University.

OBJECTIVE

To evaluate the 'Care TB®' real-time polymerase chain reaction (PCR) assay in comparison with the Amplified MTD® Test (AMTD) for the rapid diagnosis of TB.

DESIGN

Self-expectorated sputum was collected for direct smear microscopy, culture, real-time PCR and AMTD assay. Performance of the 'Care TB' real-time PCR and AMTD assay were compared using a combination of culture and clinical diagnosis as a reference standard.

RESULTS

Of the 178 sputum specimens, 83 were culture-positive; of these, 74 were Mycobacterium tuberculosis complex and 9 strains were non-tuberculous mycobacteria. The overall sensitivities and specificities were respectively 91.6% and 100% for real-time PCR, and 95.2% and 97.9% for AMTD. In the smear-positive specimens, the sensitivities and specificities were respectively 97% and 100% for real-time PCR, and 98.5% and 100% for AMTD. In the smear-negative specimens, the sensitivities and specificities were 70.6% and 100% for real-time PCR, and 82.4% and 97.7% for AMTD.

CONCLUSIONS

Both real-time PCR and AMTD are rapid and specific tests for detecting M. tuberculosis complex; however, 'Care TB' real-time PCR is more convenient and economical.

Identification and characterization of FHL3 as a novel angiogenin-binding partner

Angiogenin (Ang) is known to induce cell proliferation and inhibit apoptosis by cellular signaling pathways and by direct nuclear functions of Ang, but the mechanism of action for Ang is not yet clear. The aim of present study was to identify novel binding partner of Ang and to explore the underlying mechanism. With the use of yeast two-hybrid screening system, Ang was used as the bait to screen human fetal hepatic cDNA library for interacting proteins. Four and a half LIM domains 3 (FHL3) was identified as a novel Ang binding partner. The interaction between Ang and the full length FHL3 was further confirmed by yeast two-hybrid assay, co-immunoprecipitation and GST pull-down assays. Furthermore, FHL3 was required for Ang-mediated HeLa cell proliferation and nuclear translocation of Ang. These findings suggest that the interaction between Ang and FHL3 may provide some clues to the mechanisms of Ang-regulated cell growth and apoptosis.

Msx1 mutations: how do they cause tooth agenesis?

Mutations in the transcription factors PAX9 and MSX1 cause selective tooth agenesis in humans. In tooth bud mesenchyme of mice, both proteins are required for the expression of Bmp4, which is the key signaling factor for progression to the next step of tooth development. We have previously shown that Pax9 can transactivate a 2.4-kb Bmp4 promoter construct, and that most tooth-agenesis-causing PAX9 mutations impair DNA binding and Bmp4 promoter activation. We also found that Msx1 by itself represses transcription from this proximal Bmp4 promoter, and that, in combination with Pax9, it acts as a potentiator of Pax9-induced Bmp4 transactivation. This synergism of Msx1 with Pax9 is significant, because it is currently the only documented mechanism for Msx1-mediated activation of Bmp4. In this study, we investigated whether the 5 known tooth-agenesis-causing MSX1 missense mutations disrupt this Pax9-potentiation effect, or if they lead to deficiencies in protein stability, protein-protein interactions, nuclear translocation, and DNA-binding. We found that none of the studied molecular mechanisms yielded a satisfactory explanation for the pathogenic effects of the Msx1 mutations, calling for an entirely different approach to the investigation of this step of odontogenesis on the molecular level.

Activation of dopamine D3 receptors inhibits reward-related learning induced by cocaine

Memories of learned associations between the rewarding properties of drugs and environmental cues contribute to craving and relapse in humans. The mesocorticolimbic dopamine (DA) system is involved in reward-related learning induced by drugs of abuse. DA D3 receptors are preferentially expressed in mesocorticolimbic DA projection areas. Genetic and pharmacological studies have shown that DA D3 receptors suppress locomotor-stimulant effects of cocaine and reinstatement of cocaine-seeking behaviors. Activation of the extracellular signal-regulated kinase (ERK) induced by acute cocaine administration is also inhibited by D3 receptors. How D3 receptors modulate cocaine-induced reward-related learning and associated changes in cell signaling in reward circuits in the brain, however, have not been fully investigated. In the present study, we show that D3 receptor mutant mice exhibit potentiated acquisition of conditioned place preference (CPP) at low doses of cocaine compared to wild-type mice. Activation of ERK and CaMKIIα, but not the c-Jun N-terminal kinase and p38, in the nucleus accumbens, amygdala and prefrontal cortex is also potentiated in D3 receptor mutant mice compared to that in wild-type mice following CPP expression. These results support a model in which D3 receptors modulate reward-related learning induced by low doses of cocaine by inhibiting activation of ERK and CaMKIIα in reward circuits in the brain.

Aquaporin-4 maintains ependymal integrity in adult mice

Ependymal cells form the walls of the ventricles, and take part in the production of cerebrospinal fluid (CSF). Aquaporin-4 (AQP4), a predominant water channel of the brain, is restricted to basolateral plasma membranes of ependymal cells. The highly polarized expression of AQP4 suggests it may be involved in maintaining the structural and functional integrity of the ependyma. This hypothesis was validated by using adult AQP4 knockout mice generated by our laboratory [Fan Y, Zhang J, Sun XL, Gao L, Zeng XN, Ding JH, Cao C, Niu L, Hu G (2005) Sex- and region-specific alterations of basal amino acid and monoamine metabolism in the brain of aquaporin-4 knockout mice. J Neurosci Res 82:458-464]. Histological analysis showed disorganized ependymal layer of the lateral ventricle and aqueduct in AQP4-deficiency mice. A majority (92.7%) of null mice displayed reduced lateral ventricular volume, while a small fraction (7.3%) had enlarged or normal ventricular size with a narrow aqueduct. Immunohistochemistry demonstrated that AQP4 deletion resulted in decreased expression of gap junction protein connexin43 in the ependymal cells. Electron microscopy confirmed junctional complex absence at basolateral membranes of ependymocytes. Moreover, AQP4 knockout mice showed decreased CSF production and increased brain water content compared with wild-type mice. These results highlight a key role of AQP4 in maintaining the structure and function of the ependyma. In addition, variable profiles of ventricle system in adult AQP4 null mice indicate functional AQP4 polymorphisms.

Concentration control of carbon nanotubes in aqueous solution and its influence on the growth behavior of fibroblasts

This work investigated the biological influence of water-soluble multiwalled carbon nanotubes (wsMWCNTs) on fibroblast cell growth as a function of concentration control in an aqueous solution. The wsMWCNTs were prepared by an optimal procedure of ultrasonication/concentrated acids oxidation. The concentration of wsMWCNT in the solution was quantified by an established calibration line. A stable concentration of 0.3mg/ml was obtained in the surfactant-free water. The physicochemical properties of wsMWCNTs were characterized using scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), UV/VIS/NIR spectroscopy, and dynamic light scattering (DLS). Cell proliferation and the cell cycle were examined by MTS assay, flow cytometry and TEM respectively. Experimental results showed that the oxidation degree was a key factor that determined the concentration and stability of wsMWCNTs in the aqueous solution. The wsMWCNTs were able to enter into the cells and mainly accumulated in the cytoplasm. The wsMWCNTs-induced variations in cell proliferation and the cell cycle were concentration dependent. Cells cultivated with wsMWCNTs of 0.3mg/ml underwent a dramatic apoptosis. The proliferation was clearly suppressed when the cells were cultivated with wsMWCNTs of 0.03 mg/ml. There were no obvious influences on cell proliferation and the cell cycle when the concentration of wsMWNTs decreased to 0.01 mg/ml.

Interaction of somatostatin receptors with G proteins and cellular effector systems

Somatostatin induces its multiple biological actions by interacting with a family of receptors, referred to as sstr1-sstr5. To determine the molecular mechanisms of action of somatostatin, we have investigated the interaction of the different cloned receptors with G proteins and cellular effector systems. sstr2, sstr3 and sstr5 associate with pertussis toxin-sensitive G proteins and are able to mediate the inhibition of adenylyl cyclase activity by somatostatin. Two forms of sstr2, sstr2A and sstr2B, are generated by alternative splicing and differ in their C-terminal amino acid sequence. sstr2B couples to adenylyl cyclase whereas sstr2A does not. To investigate the basis for the differential coupling to adenylyl cyclase, we truncated sstr2B to the point of amino acid sequence divergence from sstr2A. The truncated sstr2B mediated the inhibition of cAMP formation by somatostatin, indicating that the C-terminus is not needed for coupling sstr2 to adenylyl cyclase. It is likely that the C-terminus of sstr2A hinders coupling to adenylyl cyclase. sstr2A associates with Gi alpha 3 and G(o) alpha but does not effectively interact with Gi alpha 1, a G protein that is necessary for coupling somatostatin receptors to adenylyl cyclase. The differential association of the splice variants with Gi alpha 1 may explain their contrasting effects on adenylyl cyclase activity. sstr3 also couples to adenylyl cyclase. Gi alpha 1 links sstr3 to adenylyl cyclase and mutagenesis studies have shown that the C-terminus of Gi alpha 1 is necessary for this coupling. The C-terminus of the Gi alpha proteins differ by only a few amino acid residues and only Gi alpha 1 couples sstr3 to adenylyl cyclase.(ABSTRACT TRUNCATED AT 250 WORDS)

Molecular biology of somatostatin receptors

The diverse physiological effects of somatostatin are mediated by a family of cell surface receptors that bind somatostatin selectively and with high affinity. The somatostatin receptors are members of the seven transmembrane segment receptor superfamily and molecular cloning studies have identified five types, designated sstr1-5. The human somatostatin receptors vary in size from 364 (sstr5) to 418 (sstr3) amino acids with 46-61% amino acid identity between receptors, and 105 amino acids are invariant. The sequences of the seven putative alpha-helical membrane-spanning domains are more highly conserved than those of the extracellular N- and intracellular C-terminal domains. Two forms of sstr2 have been identified in the mouse, sstr2A and sstr2B, which differ in size and sequence of the intracellular C-terminal domain. These two forms of sstr2 are products of a common gene and are generated by alternative splicing with sstr2A and sstr2B being the products of the unspliced and spliced forms, respectively, of sstr2 mRNA. Thus, functional diversity within the somatostatin receptor family may result from the expression of multiple types as well as from alternative splicing. The five somatostatin receptors have distinct patterns of expression in the central nervous system and peripheral tissues. They have also been expressed in vitro and shown to have different pharmacological properties. Somatostatin analogues selective for sstr2, sstr3 and sstr5 have been identified which will facilitate in vivo studies of the functions of these somatostatin receptors. Such studies to date suggest that sstr2 mediates inhibition of growth hormone secretion and sstr5 mediates inhibition of insulin secretion. The molecular cloning and functional characterization of the somatostatin receptor family is a first step in elucidating the diverse effects of somatostatin on cellular functions.

Improving the blood compatibility of polyurethane using carbon nanotubes as fillers and its implications to cardiovascular surgery

Blood compatibility has been an occlusion for biomaterials used in the cardiovascular system. In this work, a multiwalled carbon nanotubes-polyurethane composite (MWNT-PU) was prepared through a controlled co-precipitation. The surface chemical composition of treated carbon nanotubes was analyzed with XPS and the thermal behaviors of composite were characterized by DSC. The platelet adhesion and activation caused by the composite were evaluated by using SEM and flow cytometric analysis, respectively, and the disruption of red blood cells was analyzed through measuring the absorbance of free hemoglobin. The experimental results demonstrated that: (1) Multiwalled carbon nanotubes (MWNTs) with oxygen-containing functional groups could be well dispersed in polyurethane matrix through a controlled coprecipitation; (2) the composite surface displayed a significantly improved anticoagulant function, which can be indicative of the promising potentials of carbon nanotube-based materials in the implants and medical devices applied in blood-contacting environments.

Engineering a nicking endonuclease N.AlwI by domain swapping

Changing enzymatic function through genetic engineering still presents a challenge to molecular biologists. Here we present an example in which changing the oligomerization state of an enzyme changes its function. Type IIs restriction endonucleases such as AlwI usually fold into two separate domains: a DNA-binding domain and a catalytic/dimerization domain. We have swapped the putative dimerization domain of AlwI with a nonfunctional dimerization domain from a nicking enzyme, N.BstNBI. The resulting chimeric enzyme, N.AlwI, no longer forms a dimer. Interestingly, the monomeric N.AlwI still recognizes the same sequence as AlwI but only cleaves the DNA strand containing the sequence 5'-GGATC-3' (top strand). In contrast, the wild-type AlwI exists as a dimer in solution and cleaves two DNA strands; the top strand is cleaved by an enzyme binding to that sequence, and its complementary bottom strand is cleaved by the second enzyme dimerized with the first enzyme. N.AlwI is unable to form a dimer and therefore nicks DNA as a monomer. In addition, the engineered nicking enzyme is at least as active as the wild-type AlwI and is thus a useful enzyme. To our knowledge, this is the first report of creating a nicking enzyme by domain swapping.