Axonal response of mitochondria to demyelination and complex IV activity within demyelinated axons in experimental models of multiple sclerosis

AIMS

Axonal injury in multiple sclerosis (MS) and experimental models is most frequently detected in acutely demyelinating lesions. We recently reported a compensatory neuronal response, where mitochondria move to the acutely demyelinated axon and increase the mitochondrial content following lysolecithin-induced demyelination. We termed this homeostatic phenomenon, which is also evident in MS, the axonal response of mitochondria to demyelination (ARMD). The aim of this study is to determine whether ARMD is consistently evident in experimental demyelination and how its perturbation relates to axonal injury.

METHODS

In the present study, we assessed axonal mitochondrial content as well as axonal mitochondrial respiratory chain complex IV activity (cytochrome c oxidase or COX) of axons and related these to axonal injury in nine different experimental disease models. We used immunofluorescent histochemistry as well as sequential COX histochemistry followed by immunofluorescent labelling of mitochondria and axons.

RESULTS

We found ARMD a consistent and robust phenomenon in all experimental disease models. The increase in mitochondrial content within demyelinated axons, however, was not always accompanied by a proportionate increase in complex IV activity, particularly in highly inflammatory models such as experimental autoimmune encephalomyelitis (EAE). Axonal complex IV activity inversely correlated with the extent of axonal injury in experimental disease models.

CONCLUSIONS

Our findings indicate that ARMD is a consistent and prominent feature and emphasise the importance of complex IV activity in the context of ARMD, especially in autoimmune inflammatory demyelination, paving the way for the development of novel neuroprotective therapies.

Down-regulation of nitric oxide production by droloxifene and toremifene in human breast cancer cells

We investigated the effect of tamoxifen, 4-OH tamoxifen, toremifene droloxifene, interferon-alpha2a, interferon-alpha2b and interferon-alpha2c, singly and in combination, for their effect on nitric oxide production by MCF-7 and ZR-75-1 human breast cancer cells. Tamoxifen and 4-OH tamoxifen singly had no effect on nitric oxide production by either cell line. However, treatment with droloxifene or toremifene significantly reduced nitric oxide production by both MCF-7 and ZR-75-1 human breast cancer cell lines. Combination treatment with anti-estrogens and interferon-alpha2a interferon-alpha2b or interferon-alpha2c had no synergistic or additive effect compared to each drug singly.

Identification of the pocket factors in a picornavirus

Bovine enterovirus (BEV), along with other enteroviruses and the rhinoviruses, has a hydrophobic pocket within structural protein VP1. In the crystal structures of these viruses there is electron density commensurate with a non-protein molecule within the pocket. These molecules, termed pocket factors, have been shown to stabilise the capsid and their removal from the pocket is a necessary prerequisite to uncoating. The pocket factors have been proposed, from the electron densities and uncoating studies, to be short chain fatty acids. In order to identify the pocket factor of BEV, we have grown and purified the virus in an identical manner to that used for the crystal structure determination and have performed a lipophilic extraction. Palmitic acid, C(16:0), was the most abundant accounting for 40.8% by mass of the lipophilic extract (39.3 mol%). Myristic acid C(14:0), was next most abundant at 18.5% by mass (20.0 mol%). In addition, we have identified other fatty acids in smaller proportions. We have therefore shown that BEV contains saturated fatty acid pocket factors of varying chain length. We have also compared the profile of the fatty acyl chain composition of BEV with those for uninfected BHK-21 cell plasma membrane and endoplasmic reticulum extracts.

Bovine enterovirus as an oncolytic virus: foetal calf serum facilitates its infection of human cells

Many viruses have been investigated for their oncolytic properties and potential use as therapeutic agents for cancer treatment. Most of these replication-competent viruses are human pathogens. We investigated the oncolytic properties of an animal virus which is non pathogenic for both its natural host and humans. Bovine enterovirus has previously been shown to exhibit a very wide tissue tropism for cell types in vitro. We compare the ability of bovine enterovirus to replicate in and to cause cytopathic effect in freshly isolated human monocytes and monocyte derived macrophages with the monocyte-like U937 tumour cell line. We also include the adherent ZR-75-1 human breast cancer cell line. We have also carried out infections of bovine enterovirus in the presence and in the absence of serum of bovine origin. Our study shows that the virus will replicate in and produce cytopathic effect in the U937 and ZR-75-1 cell types to the same extent as the cells (BHK-21) in which the virus is routinely propagated. We believe bovine enterovirus to be a worthwhile candidate for further study as an anti-tumour agent.

Synergistic antitumour effect of a combination of toremifene and interferon-alpha on ZR-75-1 human breast cancer cells: dependence on interferon-alpha subtype

We investigated the effect of toremifene, interferon-alpha2a, interferon-alpha2b and interferon-alpha2c, singly and in combination for their effect on the growth of ZR-75-1 human breast cancer cells. Median effect analysis was used to determine synergistic or additive effects. Anti-proliferative studies showed that the growth of ZR-75-1 cells was inhibited to a greater extent by combination treatment with toremifene plus interferon-alpha2a, resulting in a synergistic interaction (CI <1) for all concentrations tested. A combination of toremifene plus interferon-alpha2b resulted in a synergistic interaction (CI <1) for the two highest concentrations of toremifene (10(-6) and 10(-7) M) and an additive effect (CI approximately equal to 1) for the lower concentrations (10(-8) to 10(-10) M). When toremifene was combined with interferon-alpha2c no additive or synergistic interaction was determined.

Divergent effects of paracetamol on reactive oxygen intermediate and reactive nitrogen intermediate production by U937 cells

We investigated the effects of paracetamol on reactive oxygen intermediate and reactive nitrogen intermediate production by U937 cells. Cells which had been treated with paracetamol (0.01 microM - 10 microM) exhibited a significant (p<0.001) increase in hydrogen peroxide production and a significant (p<0.001) increase in phorbol 12-myristate 13-acetate induced superoxide production. Conversely, paracetamol (0.01 microM - 10 microM) caused a significant (p<0.001) decrease in the amount of nitrite secreted into the culture medium. Our results indicate divergent effects of paracetamol on ROI and RNI production.

Violence against women--the myth of masochism

Women have been victims of violence throughout history. Freud's theory of masochism stated that women enjoyed suffering, and until very recently the mental health profession went along with this universal human tendency to blame the victim. In this paper a new understanding of the dynamics of abused wives and violence-prone husbands is being presented indicating that the explanation lies in the new field of the study of psychological reactions of victims of violence and catastrophe.