Electrophysiology of hypothalamic magnocellular neurones secreting oxytocin and vasopressin

‘Believing that the nervous system is something more than a mere system of conducting paths, I formed the hypothesis that nerve cells are true secreting cells, and act upon one other and upon the cells of other organs by the passage of a chemical substance of the nature of a ferment or proferment from the first cell to the second... When the impulse reaches the nerve ending it causes, I believe, the discharge of some of the neurosomes. (Scott, 1905¹⁹⁰).     

磁共振弥散加权成像在口腔鳞癌颈部淋巴结转移中的初步应用

目的：评价磁共振弥散加权成像（MR-DWI）在口腔鳞状细胞癌（OSCC）颈部转移性淋巴结诊断中的应用价值。方法：结合术后病理结果,分别分析51例OSCC患者的CT检查资料及20例OSCC患者的MR-DWI影像资料,采用SPSS16.0软件包中的χ2检验,比较不同检查方法对OSCC颈部转移淋巴结诊断的准确性,确定OSCC患者头颈部MR-DWI扫描的最佳参数设置。结果 ：CT、MR-DWI扫描检查淋巴结转移情况与术后病理结果的符合率分别为69.2%和85.0%。MR-DWI取b值为800s/mm2时图像质量最佳,其诊断的敏感度及特异性分别为87.5%和83.3%,CT为76.2%和63.3%。经χ2检查,MR-DWI扫描诊断结果与术后病理诊断结果具有中等相关性,Kappa值=0.694（P〈0.005）。结论：OSCC颈部转移淋巴结的MR-DWI影像特征与病理诊断结果具有较好的相关性,且与CT检查相比,MR-DWI能够更准确地预测OSCC颈部淋巴结转移情况。     

A systematic review of evidence for the role of inflammatory biomarkers in bipolar patients

Bipolar disorder (BD) is a neuropsychiatric disorder that is characterized by a phasic course of affective episodes interspersed with a euthymic state. Epidemiological, clinical, genetic, post-mortem and preclinical studies have shown that inflammatory reactions and immune modulation play a pivotal role in the pathophysiology of BD. It is conceptualized that biomarkers of inflammation and immune responses should be employed to monitor the disease process in bipolar patients. The objective of this systematic review is to analyse the inflammatory markers involved in human studies and to explore each individual marker for its potential clinical application and summarize evidence regarding their role in BD. A systematic review of human studies to measure inflammatory markers was conducted, and the studies were identified by searching PubMed/MEDLINE, PsycINFO, EMBASE, and Web of Science databases for peer-reviewed journals that were published until September 2015. In this review, we included peripheral markers, genetic, post-mortem and cell studies with inflammatory biomarker analysis in BD. One hundred and two (102) papers met the inclusion criteria. The pro-inflammatory cytokines were elevated and the anti-inflammatory cytokines were reduced in BD patients, particularly during manic and depressive phases when compared to the controls. These changes tend to disappear in euthymia, indicating that inflammation may be associated with acute phases of BD. Even though there are promising findings in this field, further clinical studies using more established detection techniques are needed to clearly show the benefit of using inflammatory markers in the diagnosis, follow-up and prognosis of patients with BD.     

Effective metabolism and long intracellular half life of the anti-hepatitis B agent adefovir in hepatic cells

Adefovir dipivoxil (ADV) is esterolytically cleaved to the 2'-deoxyadenosine monophosphate (dAMP) analog adefovir, subsequent phosphorylation leads to the formation of the anti-Hepatitis B virus (HBV) agent adefovir-DP. To better understand the mechanism of action of ADV, metabolism studies were done in Hep G2, Huh-7 and primary human hepatocytes. Separation of radiolabeled adefovir metabolites after incubation in Hep G2 cells suggested that adefovir in its mono- and di-phosphorylated forms are the only metabolites formed from adefovir. Incubation of 10 microM adefovir with hepatic cell lines and fresh monolayers of primary human hepatocytes from two donors and analysis of intracellular metabolites by liquid chromatography coupled to tandem mass spectrometry resulted in adefovir-DP levels of approximately 10 pmol/million cells. Adefovir was more efficiently phosphorylated in primary hepatocytes than cell lines with adefovir-DP accounting for 44% versus 26% of total intracellular adefovir after 24 h. Egress studies showed adefovir-DP to have a half-life of 33 +/- 3 h, 10 +/- 1 h, 48 +/- 3 h and 33 +/- 2 h in Hep G2, Huh-7, and primary hepatocytes from two separate donors, respectively. The markedly shorter half-life in Huh-7 cells was inferred to be transport dependent based on its sensitivity to the transport inhibitor MK-571. Effective phosphorylation coupled with a long intracellular half-life and small competing dATP pool sizes in primary hepatocytes forms the cellular metabolic basis for the efficacy of adefovir dipivoxil in the treatment of chronic hepatitis B.     

Human inter-individual variability in metabolism and genotoxic response to zidovudine

A mainstay of the antiretroviral drugs used for therapy of HIV-1, zidovudine (AZT) is genotoxic and becomes incorporated into DNA. Here we explored host inter-individual variability in AZT-DNA incorporation, by AZT radioimmunoassay (RIA), using 19 different strains of normal human mammary epithelial cells (NHMECs) exposed for 24 h to 200 microM AZT. Twelve of the 19 NHMEC strains showed detectable AZT-DNA incorporation levels (16 to 259 molecules of AZT/10(6) nucleotides), while 7 NHMEC strains did not show detectable AZT-DNA incorporation. In order to explore the basis for this variability, we compared the 2 NHMEC strains that showed the highest levels of AZT-DNA incorporation (H1 and H2) with 2 strains showing no detectable AZT-DNA incorporation (L1 and L2). All 4 strains had similar (> or =80%) cell survival, low levels of accumulation of cells in S-phase, and no relevant differences in response to the direct-acting mutagen bleomycin (BLM). Finally, when levels of thymidine kinase 1 (TK1), the first enzyme in the pathway for incorporation of AZT into DNA, were determined by Western blot analysis in all 19 NHMEC strains at 24 h of AZT exposure, higher TK1 protein levels were found in the 12 strains showing AZT-DNA incorporation, compared to the 7 showing no incorporation (p=0.0005, Mann-Whitney test). Furthermore, strains L1 and L2, which did not show AZT-DNA incorporation at 24 h, did have measurable incorporation by 48 and 72 h. These data suggest that variability in AZT-DNA incorporation may be modulated by inter-individual differences in the rate of induction of TK1 in response to AZT exposure.     

Covalent binding of the anticancer drug ellipticine to DNA in V79 cells transfected with human cytochrome P450 enzymes

Ellipticine is a potent antineoplastic agent whose mechanism of action is considered to be based mainly on DNA intercalation and/or inhibition of topoisomerase II. Recently, we found that ellipticine also forms covalent DNA adducts and that the formation of the major adduct is dependent on the activation of ellipticine by cytochrome P450 (CYP). We examined a panel of genetically engineered V79 cell lines including the parental line V79MZ and recombinant cells expressing the human CYP enzymes CYP1A1, CYP1A2 or CYP3A4 for their ability to activate ellipticine. The extent of activation was determined by analysing DNA adducts by 32P-postlabelling. Ellipticine was found to be toxic to all V79 cell lines with IC(50) values ranging from 0.25 to 0.40 microM. The nuclease P1 version of the 32P-postlabelling assay yielded a similar pattern of ellipticine-DNA adducts with two major adducts in all cells, the formation of only one of which was dependent on CYP activity. This pattern is identical to that detected in DNA reacted with ellipticine and the reconstituted CYP enzyme system in vitro as confirmed by HPLC of the isolated adducts. Total adduct levels ranged from 2 to 337 adducts per 10(8) nucleotides, in the parental line and in V79 expressing CYP3A4, respectively. As in vitro, human CYP1A2 and CYP1A1 were less active. The results presented here are the first report showing the formation of CYP-mediated covalent DNA adducts by ellipticine in cells in culture, and confirm the formation of covalent DNA adducts as a new mechanism of ellipticine action.     

Monoclonal antibodies to thymosin α1

Sixteen monoclonal antibodies specific for thymosin α 1 [Low et al., J. biol. Chem.254, 981–986 (1979)] obtained from two fusions with the spleens of three mice [Stähli et al., Meth. Enzym.92, 26–36 (1982b)] all react with an epitope in the C-terminal half of thymosin α 1. Human and foetal calf serum contain substances which cross-react with this epitope. A simple procedure to selectively remove the cross-reactive material and a sensitive RIA are described.     

Eccentric exercise alters muscle sensory motor control through the release of inflammatory mediators

Following downhill exercise, muscle damage and local inflammatory reactions, induced by lengthening contractions, are observed and voluntary muscle activation decreases. The hypothesis that feedback carried by the group IV muscle afferents could be involved has often been raised but never measured in vivo in these conditions. In this experiment, we tested the response of the group IV muscle afferents from the lower limb to injections of KCl and lactic acid in non-exercising rats and at 1, 2, and 8 days after one running session (-13 degrees, 16 m/min). At days 1 and 2, the baseline discharge of the group IV afferents increased, but further activation by test agents was absent. After 8 days, the afferent response was equivalent to the control response. Pretreatment with betamethasone before exercise abolished the effects of downhill exercise. In non-exercising rats, arachidonic acid evoked group IV afferent discharge and suppressed their further response to another stimulus. These results demonstrate that exhaustive downhill running highly activates, for at least 2 days, the sensory feedback carried by group IV afferents through the local release of inflammatory mediators. Such an altered sensori-motor control, accompanying the post-eccentric inflammatory syndrome, could play a key role in deterioration of muscle performance and of its voluntary activation.