Manganese chelation therapy extends survival in a mouse model of M1000 prion disease

Previous in vitro and in vivo investigations have suggested manganese (Mn(2+)) may play a role in pathogenesis through facilitating refolding of the normal cellular form of the prion protein into protease resistant, pathogenic isoforms (PrP(Sc)), as well as the subsequent promotion of higher order aggregation of these abnormal conformers. To further explore the role of Mn(2+) in pathogenesis, we undertook a number of studies, including an assessment of the disease modifying effects of chelation therapy in a well-characterized mouse model of prion disease. The di-sodium, calcium derivative of the chelator, cyclohexanediaminetetraacetic acid (Na(2)CaCDTA), was administered intraperitoneally to mice inoculated intra-cerebrally with either high or low-dose inocula, with treatment beginning early (shortly after inoculation) or late (at the usual mid-survival point of untreated mice). Analyses by inductively coupled plasma-mass spectrometry demonstrated brain Mn(2+) levels were selectively reduced by up to 50% in treated mice compared with untreated controls, with copper, iron, zinc and cobalt levels unchanged. In mice administered high-dose inocula, none of the treatment groups displayed an increase in survival although western blot analyses of early intensively treated mice showed reduced brain PrP(Sc) levels; mice infected using low-dose inocula however, showed a significant prolongation of survival (p = 0.002). Although our findings support a role for Mn(2+) in prion disease, further studies are required to more precisely delineate the extent of pathogenic involvement.

Serum matrix metalloproteinase-9 activity is dysregulated with disease progression in the mutant SOD1 transgenic mice

Amyotrophic lateral sclerosis (ALS) is an adult-onset fatal neurodegenerative disorder characterized by progressive deterioration of motor neurons in the spinal cord, brainstem, and cerebral cortex. Matrix metalloproteinase-9 (MMP-9) is proposed to be a biomarker for ALS due to a potential pathological role in the disease. However, despite numerous studies, it is still unclear whether there is a direct correlation between MMP-9 expression in serum and progression of disease. Therefore, we used a TgSOD1(G93A) mouse with a low transgene copy number. This model shows slow disease progression analogous to human ALS and provides a useful model to study biomarker expression at different stages of disease. Using zymography, we found that serum MMP-9 activity was significantly elevated in animals showing early signs of disease when compared to the younger, pre-symptomatic animals. This was followed by a decrease in MMP-9 activity in TgSOD1(G93A) mice with end-stage disease. These results were confirmed in serum of a high copy number strain of TgSOD1(G93A) mice with rapid progression. MMP-9 expression was changed accordingly in spinal motor neurons, glia and neuropil, suggesting a spinal cord contribution to blood MMP-9 activity. Serum MMP-2 activity followed a similar profile as the MMP-9 in these two models. These data indicate that circulating MMP-9 is altered throughout the course of disease progression in mice. Further studies in human ALS may validate the suitability of serum MMP-9 activity as a biomarker for early stage disease.

Membrane-targeted strategies for modulating APP and Abeta-mediated toxicity

Alzheimer's disease (AD) is a progressive neurodegenerative disease characterized by numerous pathological features including the accumulation of neurotoxic amyloid-β (Aβ) peptide. There is currently no effective therapy for AD, but the development of therapeutic strategies that target the cell membrane is gaining increased interest. The amyloid precursor protein (APP) from which Aβ is formed is a membrane-bound protein, and Aβ production and toxicity are both membrane mediated events. This review describes the critical role of cell membranes in AD with particular emphasis on how the composition and structure of the membrane and its specialized regions may influence toxic or benign Aβ/APP pathways in AD. The putative role of copper (Cu) in AD is also discussed, and we highlight how targeting the cell membrane with Cu complexes has therapeutic potential in AD.

Increasing Cu bioavailability inhibits Abeta oligomers and tau phosphorylation

Cognitive decline in Alzheimer's disease (AD) involves pathological accumulation of synaptotoxic amyloid-beta (Abeta) oligomers and hyperphosphorylated tau. Because recent evidence indicates that glycogen synthase kinase 3beta (GSK3beta) activity regulates these neurotoxic pathways, we developed an AD therapeutic strategy to target GSK3beta. The strategy involves the use of copper-bis(thiosemicarbazonoto) complexes to increase intracellular copper bioavailability and inhibit GSK3beta through activation of an Akt signaling pathway. Our lead compound Cu(II)(gtsm) significantly inhibited GSK3beta in the brains of APP/PS1 transgenic AD model mice. Cu(II)(gtsm) also decreased the abundance of Abeta trimers and phosphorylated tau, and restored performance of AD mice in the Y-maze test to levels expected for cognitively normal animals. Improvement in the Y-maze correlated directly with decreased Abeta trimer levels. This study demonstrates that increasing intracellular copper bioavailability can restore cognitive function by inhibiting the accumulation of neurotoxic Abeta trimers and phosphorylated tau.

The British Society for Antimicrobial Chemotherapy Resistance Surveillance Project: a successful collaborative model

The British Society for Antimicrobial Chemotherapy (BSAC) Resistance Surveillance Project was initiated in light of the need for UK-wide surveillance of antibacterial resistance in key clinical pathogens. The Project comprises two defined-protocol programmes that cover a range of important pathogens and antibacterials related to community-acquired respiratory tract infection and bloodstream infection, respectively. The Respiratory Programme has reported quantitative susceptibility data for Streptococcus pneumoniae, Haemophilus influenzae and Moraxella catarrhalis collected from across the UK and Ireland since 1999. The Bacteraemia Programme has reported the susceptibility of a wide range of Gram-positive and -negative organisms since 2001. The sustainability of the Programmes relies on a unique collaborative funding model: sponsorship is provided by a number of pharmaceutical companies in return for the inclusion of their investigational or marketed agents in the study alongside a core panel of established antibacterials. The sponsors have changed over time according to their interest in participating. Results for marketed agents are communicated in a timely manner through the BSAC web site and by presentation and publication, and for investigational agents with the agreement of their sponsors. The Project satisfies the requirement for sustainable defined-protocol high-quality resistance surveillance across the UK and Ireland.

Neurotoxicity of prion peptides on cultured cerebellar neurons

Prion peptide (PrP) neurotoxicity has been modelled in vitro by using synthetic peptides derived from the PrP(C) sequence. The major region of neurotoxicity has been localized to the hydrophobic domain located in the middle of the PrP sequence. The neurotoxicity assays are typically performed on cultured mouse cerebellar neurons derived from neonatal pups, and viability can be monitored by a variety of assays, including MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium); MTS (3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium, inner salt) lactate dehydrogenase release; and apoptotic assays. These neurotoxicity studies have been useful in identifying cofactors, such as PrP(C) and metals as modulators of PrP peptide-mediated neurotoxicity. Given the biosafety issues associated with handling and purifying infectious prions, the use of synthetic peptides that display a dependence upon PrP(C) expression for toxicity, as per the PrP(Sc) agent for infectivity, supports the relevance of using these synthetic peptides for understanding PrP-mediated neurotoxicity.

Neurotoxicity from glutathione depletion is mediated by Cu-dependent p53 activation

Loss of intracellular neuronal glutathione (GSH) is an important feature of neurodegenerative disorders including Alzheimer's disease, Parkinson's disease, and amyotrophic lateral sclerosis. The consequences of GSH depletion include increased oxidative damage to proteins, lipids, and DNA and subsequent cytotoxic effects. GSH is also an important modulator of cellular copper (Cu) homeostasis and altered Cu metabolism is central to the pathology of several neurodegenerative diseases. The cytotoxic effects of Cu in cells depleted of GSH are not well understood. We have previously reported that depletion of neuronal GSH levels results in cell death from trace levels of extracellular Cu due to elevated Cu(I)-mediated free radical production. In this study we further examined the molecular pathway of trace Cu toxicity in neurons and fibroblasts depleted of GSH. Treatment of primary cortical neurons or 3T3 fibroblasts with the glutathione synthetase inhibitor buthionine sulfoximine resulted in substantial loss of intracellular GSH and increased cytotoxicity. We found that both neurons and fibroblasts revealed increased expression and activation of p53 after depletion of GSH. The increased p53 activity was induced by extracellular trace Cu. Furthermore, we showed that in GSH-depleted cells, Cu induced an increase in oxidative stress resulting in DNA damage and activation of p53-dependent cell death. These findings may have important implications for neurodegenerative disorders that involve GSH depletion and aberrant Cu metabolism.

Clioquinol promotes cancer cell toxicity through tumor necrosis factor alpha release from macrophages

Copper has an important role in cancer growth, angiogenesis, and metastasis. Previous studies have shown that cell-permeable metal ligands, including clioquinol (CQ) and pyrrolidine dithiocarbamate, inhibit cancer cell growth in cell culture and in vivo. The mechanism of action has not been fully determined but may involve metal-mediated inhibition of cancer cell proteasome activity. However, these studies do not fully account for the ability of cell-permeable metal ligands to inhibit cancer cell growth without affecting normal cells. In this study, we examined the effect of CQ on macrophage-mediated inhibition of HeLa cancer cell growth in vitro. When CQ was added to RAW 264.7 macrophage-HeLa cell cocultures, a substantial increase in HeLa cell toxicity was observed compared with CQ treatment of HeLa cells cultured alone. Transfer of conditioned medium from CQ-treated macrophages to HeLa cells also induced HeLa cell toxicity, demonstrating the role of secreted factors in the macrophage-mediated effect. Further investigation revealed that CQ induced copper-dependent activation of macrophages and release of tumor necrosis factor (TNF) alpha. In studies with recombinant TNFalpha, we showed that the level of TNFalpha released by CQ-treated macrophages was sufficient to induce HeLa cell toxicity. Moreover, the toxic effect of conditioned medium from CQ-treated macrophages could be prevented by addition of neutralizing antibodies to TNFalpha. These studies demonstrate that CQ can induce cancer cell toxicity through metal-dependent release of TNFalpha from macrophages. Our results may help to explain the targeted inhibition of tumor growth in vivo by CQ.

Mechanisms of A beta mediated neurodegeneration in Alzheimer's disease

Development of a comprehensive therapeutic treatment for the neurodegenerative Alzheimer's disease (AD) is limited by our understanding of the underlying biochemical mechanisms that drive neuronal failure. Numerous dysfunctional mechanisms have been described in AD, ranging from protein aggregation and oxidative stress to biometal dyshomeostasis and mitochondrial failure. In this review we discuss the critical role of amyloid-beta (A beta) in some of these potential mechanisms of neurodegeneration. The 39-43 amino acid A beta peptide has attracted intense research focus since it was identified as a major constituent of the amyloid deposits that characterise the AD brain, and it is now widely recognised as central to the development of AD. Familial forms of AD involve mutations that lead directly to altered A beta production from the amyloid-beta A4 precursor protein, and the degree of AD severity correlates with specific pools of A beta within the brain. A beta contributes directly to oxidative stress, mitochondrial dysfunction, impaired synaptic transmission, the disruption of membrane integrity, and impaired axonal transport. Further study of the mechanisms of A beta mediated neurodegeneration will considerably improve our understanding of AD, and may provide fundamental insights needed for the development of more effective therapeutic strategies.

The modulation of metal bio-availability as a therapeutic strategy for the treatment of Alzheimer's disease

The postmortem Alzheimer's disease brain is characterized histochemically by the presence of extracellular amyloid plaques and neurofibrillary tangles. Also consistent with the disease is evidence for chronic oxidative damage within the brain. Considerable research data indicates that these three critical aspects of Alzheimer's disease are interdependent, raising the possibility that they share some commonality with respect to the ever elusive initial factor(s) that triggers the development of Alzheimer's disease. Here, we discuss reports that show a loss of metal homeostasis is also an important event in Alzheimer's disease, and we identify how metal dyshomeostasis may contribute to development of the amyloid-beta, tau and oxidative stress biology of Alzheimer's disease. We propose that therapeutic agents designed to modulate metal bio-availability have the potential to ameliorate several of the dysfunctional events characteristic of Alzheimer's disease. Metal-based therapeutics have already provided promising results for the treatment of Alzheimer's disease, and new generations of pharmaceuticals are being developed. In this review, we focus on copper dyshomeostasis in Alzheimer's disease, but we also discuss zinc and iron.

Nine-Year Trends And Racial And Ethnic Disparities in Women's Awareness of Heart Disease And Stroke: An American Heart Association National Study

BACKGROUND

The purpose of this study was to evaluate trends in women's awareness, knowledge, and perceptions related to cardiovascular disease (CVD) since 1997, when the American Heart Association initiated a national campaign for women.

METHODS AND RESULTS

A nationally representative sample of 1,005 women identified through random digit dialing (mean age 50 years, 71% white) was surveyed in 2006, and results were compared with results of similar surveys conducted in 2003, 2000, and 1997. Awareness, knowledge, and perceptions related to CVD were evaluated using a standardized interviewer-assisted questionnaire. In 2006, awareness of heart disease as the leading cause of death among women was 57%; significantly higher than in prior surveys (p < 0.001). Awareness was lower among black and Hispanic women compared with white women (31% and 29% vs. 68%, p < 0.05), and the racial/ethnic difference has not appreciably changed over time. More than twice as many women felt uninformed about stroke compared to heart disease in 2006 (23% vs. 11%, p < 0.05). Hispanic women were more likely than white women to report that there is nothing they can do to keep themselves from getting CVD (22% vs. 11%, p < 0.05). The majority of respondents (> or = 50%) reported confusion related to basic CVD prevention strategies.

CONCLUSIONS

CVD awareness has increased significantly among women since 1997, yet the racial/ethnic gap in awareness has not narrowed. Educational efforts to increase heart disease and stroke awareness should be targeted to racial/ethnic minorities, especially Hispanics. Methods to reinforce basic CVD prevention strategies are needed.

Oxidized low-density lipoprotein-dependent endothelial arginase II activation contributes to impaired nitric oxide signaling

Oxidized low-density lipoprotein (OxLDL) impairs NO signaling and endothelial function, and contributes to the pathogenesis of atherosclerosis. Arginase reciprocally regulates NO levels in endothelial cells by competing with NO synthase for the substrate l-arginine. In human aortic endothelial cells, OxLDL stimulation increased arginase enzyme activity in a time- and dose-dependent manner. Arginase activity reached its maximum as early as 5 minutes, was maintained for a period of more than 48 hours, and was associated with a reciprocal decrease in NO metabolite (NOx [nitrite and nitrate]) production. Furthermore, OxLDL induced arginase II mRNA expression after 4 hours. Small interfering RNA targeted to arginase II decreased both the quantity and the activity of arginase from baseline, prevented OxLDL-dependent increases in arginase activity, and induced an increase in NOx production. Immunofluorescence analysis revealed an association of arginase II with the microtubule cytoskeleton. Microtubule disruption with nocodazole caused a dramatic redistribution of arginase II to a diffuse cytosolic pattern, increased arginase activity, and decreased NOx production, which was restored in the presence of the specific arginase inhibitor (S)-(2-boronoethyl)-l-cysteine (BEC). On the other hand, epothilone B prevented microtubule disruption and inhibited OxLDL-dependent increases in arginase activity and attenuated OxLDL-dependent decreases in NOx. Preincubation of rat aortic rings with OxLDL resulted in an increase in arginase activity and a decrease in NOx production. This was reversed by arginase inhibition with the BEC. Thus, OxLDLs increase arginase activity by a sequence of regulatory events that involve early activation through decreased association with microtubules and a later increase in transcription. Furthermore, increased arginase activity contributes to OxLDL-dependent impairment of NOx production. Arginase, therefore, represents a novel target for therapy in atherosclerosis.

A profile of olympic taekwondo competitors

The purpose of this study was to identify the profile of the Olympic champions and the other competitors who were involved in the Games. The information on each of the athletes was obtained from the "Official Site of the Sydney 2000 Olympic Games, www.olympics.com/eng/sports/TK "and included weight category, weight, height, age, points obtained, warnings, deduction point, defensive/offensive kicks and punches. One hundred and two athletes competed (54 males and 48 females) in the Games. The mean average age and BMI (Body Mass Index) of 16 male winners was 24.4 ± 3.3 years and 21.9 ± 2.4 respectively compared to 25.2 ± 4.3 years and 22.8 ± 3.3 for the 38 male non-winners. The mean average age and BMI of the 16 female winners was 23.1 ± 3.9 years and 20.8 ± 2.3 respectively compared to 24.9 ± 4.7 years and 21.3 ± 2.7 for the 32 female non-winners. For all four types of athletes, offensive kicks accounted for at least 52% of the techniques to score a point. Ninety-eight percent of all techniques used to score were kicks. Although not statistically significant, winners overall tended to be younger in age and taller with slightly lower BMI than their weight category average. Taking into account the literature cited in this article, future studies should be designed to examine the relationship between performance and functional variables such as muscle power, muscle endurance, reaction time and aerobic capacity. Key PointsWinners tended to be younger in age and taller with slightly lower BMI than their weight category average.An offensive technique was used to score slightly more often than a defensive one.Overall, 98% of all techniques used to score were kicks.

Metal homeostasis in Alzheimer's disease

Alzheimer's disease (AD) is a progressive neurodegenerative disorder characterized by neuronal dysfunction and the formation of amyloid plaques in the brain. Although the pathological processes resulting in the onset and progression of AD are not well understood, there is a growing body of evidence to support a central role for biometals in many critical aspects of the illness. Recent reports have described the exciting development of potential therapeutic agents based on the modulation of metal bioavailability. The metal ligand, clioquinol has demonstrated promising results in animal models and small clinical trials and a new generation of metal ligand-based therapeutics are currently under development. However, further research is necessary to fully understand the complex and interdependent pathways of biometal homeostasis and amyloid metabolism in AD. This information will be vital for the development of safe and effective metal-based pharmaceuticals for the treatment of AD and, potentially, other neurodegenerative disorders.

Autogenic training for tension type headaches: A systematic review of controlled trials

OBJECTIVE

To determine from the published evidence whether autogenic training as sole therapy is effective for prevention of tension-type headaches in adults.

METHOD

Systematic review of controlled trials. Literature searches were performed in January 2005 in six major databases, specifically Medline, EMBASE, AMED, CENTRAL, PsychInfo and CINAHL and information was extracted and evaluated in a pre-defined manner.

RESULTS

Seven controlled clinical trials were included in the review. The methodological quality of these studies was low. Patient samples were generally representative of the more severely affected cases. None of the studies show autogenic training to be convincingly superior to other interventions care. Some trials suggested that the effect of autogenic training is no different from hypnosis and inferior to biofeedback.

CONCLUSION

There is no consistent evidence to suggest that autogenic training is superior to other interventions for prevention of tension headaches, or different from other forms of relaxation. Further studies should investigate the use of standard autogenic training in patients with moderate headache.

Degradation of the Alzheimer Disease Amyloid β-Peptide by Metal-dependent Up-regulation of Metalloprotease Activity

Biometals play an important role in Alzheimer disease, and recent reports have described the development of potential therapeutic agents based on modulation of metal bioavailability. The metal ligand clioquinol (CQ) has shown promising results in animal models and small phase clinical trials; however, the actual mode of action in vivo has not been determined. We now report a novel effect of CQ on amyloid beta-peptide (Abeta) metabolism in cell culture. Treatment of Chinese hamster ovary cells overexpressing amyloid precursor protein with CQ and Cu(2+) or Zn(2+) resulted in an approximately 85-90% reduction of secreted Abeta-(1-40) and Abeta-(1-42) compared with untreated controls. Analogous effects were seen in amyloid precursor protein-overexpressing neuroblastoma cells. The secreted Abeta was rapidly degraded through up-regulation of matrix metalloprotease (MMP)-2 and MMP-3 after addition of CQ and Cu(2+). MMP activity was increased through activation of phosphoinositol 3-kinase and JNK. CQ and Cu(2+) also promoted phosphorylation of glycogen synthase kinase-3, and this potentiated activation of JNK and loss of Abeta-(1-40). Our findings identify an alternative mechanism of action for CQ in the reduction of Abeta deposition in the brains of CQ-treated animals and potentially in Alzheimer disease patients.

Overexpression of Abeta is associated with acceleration of onset of motor impairment and superoxide dismutase 1 aggregation in an amyotrophic lateral sclerosis mouse model

Transgenic mice carrying mutant Cu/Zn superoxide dismutase (SOD1) recapitulate the motor impairment of human amyotrophic lateral sclerosis (ALS). The amyloid-beta (Abeta) peptide associated with Alzheimer's disease is neurotoxic. To investigate the potential role of Abeta in ALS development, we generated a double transgenic mouse line that overexpresses SOD1(G93A) and amyloid precursor protein (APP)-C100. The transgenic mouse C100.SOD1(G93A) overexpresses Abeta and shows earlier onset of motor impairment but has the same lifespan as the single transgenic SOD1(G93A) mouse. To determine the mechanism associated with this early-onset phenotype, we measured copper and zinc levels in brain and spinal cord and found both significantly elevated in the single and double transgenic mice compared with their littermate control mice. Increased glial fibrillary acidic protein and decreased APP levels in the spinal cord of C100.SOD1(G93A) mice compared with the SOD1(G93A) mice agree with the neuronal damage observed by immunohistochemical analysis. In the spinal cords of C100.SOD1(G93A) double transgenic mice, soluble Abeta was elevated in mice at end-stage disease compared with the pre-symptomatic stage. Buffer-insoluble SOD1 aggregates were significantly elevated in the pre-symptomatic mice of C100.SOD1(G93A) compared with the age-matched SOD1(G93A) mice, correlating with the earlier onset of motor impairment in the C100.SOD1(G93A) mice. This study supports abnormal SOD1 protein aggregation as the pathogenic mechanism in ALS, and implicates a potential role for Abeta in the development of ALS by exacerbating SOD1(G93A) aggregation.

The Alexander Project: the benefits from a decade of surveillance

The Alexander Project, initiated in 1992 as an international, multicentre, longitudinal surveillance study of antimicrobial susceptibility among common respiratory pathogens, has been pivotal in defining the role of global surveillance. At the time, there were few studies in which data were collected in a way that allowed meaningful comparisons to be made between studies, locations or over time. The project instituted the use of a central laboratory and standardized methods for the collection of isolates and determination of susceptibility, and this was continued with the addition of two further reference laboratories. Data from the study have provided a resource for measuring trends in the susceptibility patterns of Streptococcus pneumoniae, Haemophilus influenzae and Moraxella catarrhalis at country, regional and global levels. Determination and publication of quantitative MICs enabled detailed assessment of changes in susceptibility distributions and assessment of microbiological and potential clinical susceptibility using different breakpoints, including those based on pharmacokinetic/pharmacodynamic parameters. Comparisons of antimicrobial usage patterns and resistance prevalences over time allowed hypotheses to be examined with respect to the role of quantity and type of antimicrobial use in the selection and spread of resistance. The resulting collection of isolates has provided a valuable resource for molecular studies into the evolution of resistance over time and location; a substantial proportion of this collection is now in the public domain. This paper reviews the 10 years of the Alexander Project and the benefits it has brought to an understanding of the evolution of antibacterial resistance in community respiratory bacteria.

Acupuncture and related interventions for smoking cessation

BACKGROUND

Acupuncture and related techniques are promoted as a treatment for smoking cessation in the belief that they may reduce nicotine withdrawal symptoms.

OBJECTIVES

The objectives of this review are to determine the effectiveness of acupuncture and the related interventions of acupressure, laser therapy and electrostimulation, in smoking cessation in comparison with no intervention, sham treatment, or other interventions.

SEARCH STRATEGY

We searched the Cochrane Tobacco Addiction Group specialized register, the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, EMBASE, BIOSIS Previews, PsycINFO, Science and Social Sciences Citation Index, AMED and CISCOM. Date of last search January 2005.

SELECTION CRITERIA

Randomized trials comparing a form of acupuncture, acupressure, laser therapy or electrostimulation with either no intervention, sham treatment or another intervention for smoking cessation.

DATA COLLECTION AND ANALYSIS

We extracted data in duplicate on the type of smokers recruited, the nature of the acupuncture and control procedures, the outcome measures, method of randomization, and completeness of follow up. We assessed abstinence from smoking at the earliest time-point (before six weeks), and at the last measurement point between six months and one year. We used the most rigorous definition of abstinence for each trial, and biochemically validated rates if available. Those lost to follow up were counted as continuing smokers. Where appropriate, we performed meta-analysis using a fixed-effect model.

MAIN RESULTS

We identified 24 reports of studies. The only comparison for which there were sufficient studies to combine meaningfully was acupuncture compared with sham acupuncture. The fixed-effect odds ratio (OR) for the short-term effect was 1.36 (95% confidence interval 1.07 to 1.72), but the studies are heterogeneous and the result is strongly influenced by one individual positive study. The significant short-term effect was lost with the random-effects model for pooling, or by removing the outlying study that led to heterogeneity. The long-term result shows no effect of acupuncture compared with sham acupuncture. There was no consistent evidence that acupuncture is superior to no treatment, and no evidence that the effect of acupuncture was different from that of other anti-smoking interventions, or that any particular acupuncture technique is superior to other techniques.

AUTHORS' CONCLUSIONS

There is no consistent evidence that acupuncture, acupressure, laser therapy or electrostimulation are effective for smoking cessation, but methodological problems mean that no firm conclusions can be drawn. Further research using frequent or continuous stimulation is justified.

Therapeutic treatments for Alzheimer's disease based on metal bioavailability

The amyloid beta peptide (Abeta) has been widely implicated as a significant causative agent in Alzheimer's disease, although the common mechanistic links between Abeta and other critical elements of Alzheimer's disease, such as advancing age and oxidative stress, are still poorly understood. Here we review data indicating that biometal dyshomeostasis plays a role in these aspects of Alzheimer's disease. Although strong evidence has been published demonstrating a role for iron and zinc in Alzheimer's disease, we have here limited our discussion to data on the role of copper. We also describe how the development of therapeutic agents designed to modulate metal bioavailability has provided promising results in the treatment of Alzheimer's disease. The metal ligand clioquinol has been used successfully in vitro, as well as in animal models and small clinical trials, and a new generation of metal ligand-based therapeutics is under development.

Correlative studies support lipid peroxidation is linked to PrPres propagation as an early primary pathogenic event in prion disease

To assess whether heightened oxidative stress plays an early and primary pathogenic role in transmissible spongiform encephalopathies (TSE), we undertook detailed correlative studies using a mouse-adapted model of human disease. The spatio-temporal evolution of the abnormal, protease-resistant isoform of the prion protein (PrP(res)) and neuropathological changes were correlated with the occurrence and type of oxidative stress. Heightened oxidative stress was demonstrated, but restricted to elevated levels of free aldehydic breakdown products of lipid peroxidation, affecting all brain regions to varying extents. The increase in lipid peroxidation was highest over the mid-incubation period, with the onset showing close temporal and general topographical concordance with the first detection of PrP(res) with both pre-empting the typical neuropathological changes of spongiform change, gliosis and neuronal loss. Further, prion propagation over the disease course was assessed using murine bioassay. This revealed that the initial rapid increase in infectivity titres was contemporaneous with the abrupt onset and maximisation of lipid peroxidation. The present results are an important extension to previous studies, showing that heightened oxidative stress in the form of lipid peroxidation is likely to constitute an early primary pathogenic event in TSE, associated temporally with the integral disease processes of prion propagation and PrP(res) formation, and consistent with causal links between these events and subsequent typical neuropathological changes.

Knockdown of arginase I restores NO signaling in the vasculature of old rats

Arginase, expressed in endothelial cells and upregulated in aging blood vessels, competes with NO synthase (NOS) for l-arginine, thus modulating vasoreactivity and attenuating NO signaling. Moreover, arginase inhibition restores endothelial NOS signaling and l-arginine responsiveness in old rat aorta. The arginase isoform responsible for modulating NOS, however, remains unknown. Because isoform-specific arginase inhibitors are unavailable, we used an antisense (AS) oligonucleotide approach to knockdown arginase I (Arg I). Western blot and quantitative PCR confirmed that Arg I is the predominant isoform expressed in endothelialized aortic rings and is upregulated in old rats compared with young. Aortic rings from 22-month-old rats were incubated for 24 hours with sense (S), AS oligonucleotides, or medium alone (C). Immunohistochemistry, immunoblotting, and enzyme assay confirmed a significant knockdown of Arg I protein and arginase activity in AS but not S or C rings. Conversely, calcium-dependent NOS activity and vascular metabolites of NO was increased in AS versus S or C rings. Acetylcholine (endothelial-dependent) vasorelaxant responses were enhanced in AS versus S or C treated rings. In addition, 1H-oxadiazolo quinoxalin-1-one (10 micromol/L), a soluble guanylyl cyclase inhibitor, increased the phenylephrine response in AS compared with S and C rings suggesting increased NO bioavailability. Finally, l-arginine (0.1 mmol/L)-induced relaxation was increased in AS versus C rings. These data support our hypothesis that Arg I plays a critical role in the pathobiology of age-related endothelial dysfunction. AS oligonucleotides may, therefore, represent a novel therapeutic strategy against age-related vascular endothelial dysfunction.

In vitro gamma-secretase cleavage of the Alzheimer's amyloid precursor protein correlates to a subset of presenilin complexes and is inhibited by zinc

The gamma-secretase complex mediates the final proteolytic event in Alzheimer's disease amyloid-beta biogenesis. This membrane complex of presenilin, anterior pharynx defective, nicastrin, and presenilin enhancer-2 cleaves the C-terminal 99-amino acid fragment of the amyloid precursor protein intramembranously at gamma-sites to form C-terminally heterogeneous amyloid-beta and cleaves at an epsilon-site to release the intracellular domain or epsilon-C-terminal fragment. In this work, two novel in vitro gamma-secretase assays are developed to further explore the biochemical characteristics of gamma-secretase activity. During development of a bacterial expression system for a substrate based on the amyloid precursor protein C-terminal 99-amino acid sequence, fragments similar to amyloid-beta and an epsilon-C-terminal fragment were observed. Upon purification this substrate was used in parallel with a transfected source of substrate to measure gamma-secretase activity from detergent extracted membranes. With these systems, it was determined that recovery of size-fractionated cellular and tissue-derived gamma-secretase activity is dependent upon detergent concentration and that activity correlates to a subset of high molecular mass presenilin complexes. We also show that by changing the solvent environment with dimethyl sulfoxide, detection of epsilon-C-terminal fragments can be elevated. Lastly, we show that zinc causes an increase in the apparent molecular mass of an amyloid precursor protein gamma-secretase substrate and inhibits its cleavage. These studies further refine our knowledge of the complexes and biochemical factors needed for gamma-secretase activity and suggest a mechanism by which zinc dysregulation may contribute to Alzheimer's disease pathogenesis.

P66shc regulates endothelial NO production and endothelium-dependent vasorelaxation: implications for age-associated vascular dysfunction

The p66shc adaptor protein mediates age-associated oxidative stress. We examined the role of p66shc in endothelial nitric oxide synthase (eNOS) signaling. Overexpression of p66shc inhibited eNOS-dependent NO production. RNAi-mediated down-regulation of endogenous p66shc led to activation of the proto-oncogene ras, and Akt kinase, with a corresponding increase in phosphorylation of eNOS at S1177 (S1179 on bovine eNOS). In rat aortic rings, down-regulation of p66shc suppressed the vasoconstrictor response to phenyephrine that was abrogated by treatment with the NOS inhibitor l-NAME, and enhanced vasodilation induced by sub-maximal doses of acetylcholine. These findings highlight a pivotal role for p66shc in inhibiting endothelial NO production, and endothelium-dependent vasorelaxation, that may provide important mechanistic information about endothelial dysfunction seen with aging.

The Evolution of Oscillatory Behavior in Age‐Structured Species

A major challenge in ecology is to explain why so many species show oscillatory population dynamics and why the oscillations commonly occur with particular periods. The background environment, through noise or seasonality, is one possible driver of these oscillations, as are the components of the trophic web with which the species interacts. However, the oscillation may also be intrinsic, generated by density-dependent effects on the life history. Models of structured single-species systems indicate that a much broader range of oscillatory behavior than that seen in nature is theoretically possible. We test the hypothesis that it is selection that acts to constrain the range of periods. We analyze a nonlinear single-species matrix model with density dependence affecting reproduction and with trade-offs between reproduction and survival. We show that the evolutionarily stable state is oscillatory and has a period roughly twice the time to maturation, in line with observed patterns of periodicity. The robustness of this result to variations in trade-off function and density dependence is tested.

Increasing prevalence of multidrug-resistant Streptococcus pneumoniae in the United States over a 10-year period: Alexander Project

The Alexander Project is a global surveillance study conducted from 1992 to 2001. Minimum inhibitory concentrations and percent resistance to a panel of antimicrobial agents were determined according to National Committee for Clinical Laboratory Standards methodology. Resistance to penicillin (PEN-R) and erythromycin (ERY-R) have increased in the period 1992-2001 by 3.9 and 4.5 times to 20.7% and 27.9%, respectively. Joint PEN-ERY-R has increased 4.9 times, up to 15.3%. In 1992, 57.1% of all PEN-R isolates were also ERY-R, whereas in 2001, 75.8% were ERY-R. Resistance to only 1 antibiotic increased slightly, from 8% in 1992 to 12% in 2001, whereas resistance to more than 1 antibiotic increased 4.3 times, from 6.4% in 1992 to 27.8% of all strains in 2001. Multidrug-resistant pneumococci are an increasingly common finding in the United States. Three of four PEN-R isolates are also multiresistant. The rate of growth of multidrug resistance is higher than that of single antibiotic resistance.

Peptide-oligonucleotide hybrids in antisense therapy

Antisense technology provides outstanding promise for treatment of human disease, having broad applicability and high specificity. Although advances have been made in antisense oligonucleotide chemistry, leading to increased plasma and cellular stability, and decreased toxicity, considerable potential remains for the enhancement of oligonucleotide uptake for targeted delivery of oligonucleotides. One promising avenue for achieving this is via linkage of antisense oligonucleotides to peptide carriers. This review looks at the current status of developments in this area.

Apurinic/apyrimidinic endonuclease 1 regulates endothelial NO production and vascular tone

The dual-function protein apurinic/apyrimidinic endonuclease/redox factor-1 (APE1/ref-1) is essential for DNA repair and also governs the reductive activation of many redox-sensitive transcription factors. We examined the role of APE1/ref-1 in regulation of endothelium-dependent tone and systemic blood pressure. APE1/ref-1+/- mice have impaired endothelium-dependent vasorelaxation, reduced vascular NO levels, and are hypertensive. APE1/ref-1 upregulates H-ras expression and leads to H-ras-mediated, phosphoinositide-3 kinase/Akt kinase-dependent calcium sensitization of endothelial NO synthase (eNOS), stimulating NO production. The reducing property of APE1/ref-1 is essential for upregulation of H-ras and for the calcium sensitization of eNOS. These findings uncover a novel physiological role for APE1/ref-1 in regulating vascular tone by governance of eNOS activity and bioavailable NO.

Gene knockout of amyloid precursor protein and amyloid precursor-like protein-2 increases cellular copper levels in primary mouse cortical neurons and embryonic fibroblasts

Alzheimer's disease is characterised by the accumulation of amyloid-beta peptide, which is cleaved from the copper-binding amyloid-beta precursor protein. Recent in vivo and in vitro studies have illustrated the importance of copper in Alzheimer's disease neuropathogenesis and suggested a role for amyloid-beta precursor protein and amyloid-beta in copper homeostasis. Amyloid-beta precursor protein is a member of a multigene family, including amyloid precursor-like proteins-1 and -2. The copper-binding domain is similar among amyloid-beta precursor protein family members, suggesting an overall conservation in its function or activity. Here, we demonstrate that double knockout of amyloid-beta precursor protein and amyloid precursor-like protein-2 expression results in significant increases in copper accumulation in mouse primary cortical neurons and embryonic fibroblasts. In contrast, over-expression of amyloid-beta precursor protein in transgenic mice results in significantly reduced copper levels in primary cortical neurons. These findings provide cellular neuronal evidence for the role of amyloid-beta precursor protein in copper homeostasis and support the existing hypothesis that amyloid-beta precursor protein and amyloid precursor-like protein-2 are copper-binding proteins with functionally interchangeable roles in copper homeostasis.

Augmentin (amoxicillin/clavulanate) in the treatment of community-acquired respiratory tract infection: a review of the continuing development of an innovative antimicrobial agent

Amoxicillin/clavulanate (Augmentin) is a broad-spectrum antibacterial that has been available for clinical use in a wide range of indications for over 20 years and is now used primarily in the treatment of community-acquired respiratory tract infections. Amoxicillin/clavulanate was developed to provide a potent broad spectrum of antibacterial activity, coverage of beta-lactamase-producing pathogens and a favourable pharmacokinetic/pharmacodynamic (PK/PD) profile. These factors have contributed to the high bacteriological and clinical efficacy of amoxicillin/clavulanate in respiratory tract infection over more than 20 years. This is against a background of increasing prevalence of antimicrobial resistance, notably the continued spread of beta-lactamase-mediated resistance in Haemophilus influenzae and Moraxella catarrhalis, and penicillin, macrolide and quinolone resistance in Streptococcus pneumoniae. The low propensity of amoxicillin/clavulanate to select resistance mutations as well as a favourable PK/PD profile predictive of high bacteriological efficacy may account for the longevity of this combination in clinical use. However, in certain defined geographical areas, the emergence of S. pneumoniae strains with elevated penicillin MICs has been observed. In order to meet the need to treat drug-resistant S. pneumoniae, two new high-dose amoxicillin/clavulanate formulations have been developed. A pharmacokinetically enhanced tablet dosage form of amoxicillin/clavulanate 2000/125 mg twice daily (available as Augmentin XR in the USA), has been developed for use in adult respiratory tract infection due to drug-resistant pathogens, such as S. pneumoniae with reduced susceptibility to penicillin, as well as beta-lactamase-producing H. influenzae and M. catarrhalis. Amoxicillin/clavulanate 90/6.4 mg/kg/day in two divided doses (Augmentin ES-600) is for paediatric use in persistent or recurrent acute otitis media where there are risk factors for the involvement of beta-lactamase-producing strains or S. pneumoniae with reduced penicillin susceptibility. In addition to high efficacy, amoxicillin/clavulanate has a well known safety and tolerance profile of the two new high-dose formulations are not significantly different from those of conventional formulations. Amoxicillin/clavulanate is included in guidelines and recommendations for the treatment of bacterial sinusitis, acute otitis media, community-acquired pneumonia and acute exacerbations of chronic bronchitis. Amoxicillin/clavulanate continues to be an important agent in the treatment of community-acquired respiratory tract infections, both now and in the future.

Autogenic training reduces anxiety after coronary angioplasty: a randomized clinical trial

OBJECTIVES

Autogenic training (AT) is a method of autosuggestion with some potential for reducing anxiety. This study tests whether AT lowers anxiety levels experienced by patients undergoing coronary angioplasty.

METHODS

Fifty-nine patients were randomly assigned to receive regular AT or no such therapy as an adjunct to standard care for 5 months. The primary outcome measure was State Anxiety at 2 months. Qualitative information was generated by face-to-face interviews.

RESULTS

State Anxiety showed a significant intergroup difference both at 2 and 5 months. This finding was corroborated by secondary outcome measures, for example, quality of life, and by qualitative information about patients' experiences. The results do not allow us to determine whether the observed effects are specific to AT or of a nonspecific nature.

CONCLUSIONS

Our results suggest that AT may have a role in reducing anxiety of patients undergoing coronary angioplasty.

Immunotherapy as a therapeutic treatment for neurodegenerative disorders

Human neurodegenerative illnesses such as Alzheimer's disease and Creutzfeldt-Jakob disease exact an enormous cost on individuals, families and society. For these and related disorders, current treatment is largely symptomatic without influencing the underlying disease process. Until recently, the development of immunotherapeutic approaches to neurodegenerative disorders had been almost completely ignored despite growing successes against other non-infectious diseases such as cancer. However, since Schenk and colleagues described the antibody-mediated clearance of amyloid plaques in a transgenic mouse model of Alzheimer's disease, a number of studies have confirmed the feasibility of this strategy for several neurodegenerative disorders including Huntington's disease and prion diseases. These reports offer the exciting prospect that either the immune system or its derivative components can be harnessed to fight the misfolded and/or aggregated proteins that accumulate in many neurodegenerative illnesses. If the remarkable power of clonal expansion, specificity and efficiency of the immune system can successfully inactivate these abnormal proteins, real hope exists that effective immunotherapeutic treatments for neurodegenerative illnesses may be available in the near future.

Iron inhibits neurotoxicity induced by trace copper and biological reductants

The extracellular microenvironment of the brain contains numerous biological redox agents, including ascorbate, glutathione, cysteine and homocysteine. During ischemia/reperfusion, aging or neurological disease, extracellular levels of reductants can increase dramatically owing to dysregulated homeostasis. The extracellular concentrations of transition metals such as copper and iron are also substantially elevated during aging and in some neurodegenerative disorders. Increases in the extracellular redox capacity can potentially generate neurotoxic free radicals from reduction of Cu(II) or Fe(III), resulting in neuronal cell death. To investigate this in vitro, the effects of extracellular reductants (ascorbate, glutathione, cysteine, homocysteine or methionine) on primary cortical neurons was examined. All redox agents except methionine induced widespread neuronal oxidative stress and subsequent cell death at concentrations occurring in normal conditions or during neurological insults. This neurotoxicity was totally dependent on trace Cu (>or=0.4 microM) already present in the culture medium and did not require addition of exogenous Cu. Toxicity involved generation of Cu(I) and H(2)O(2), while other trace metals did not induce toxicity. Surprisingly, administration of Fe(II) or Fe(III) (>or=2.5 microM) completely abrogated reductant-mediated neurotoxicity. The potent protective activity of Fe correlated with Fe inhibiting reductant-mediated Cu(I) and H(2)O(2) generation in cell-free assays and reduced cellular Cu uptake by neurons. This demonstrates a novel role for Fe in blocking Cu-mediated neurotoxicity in a high reducing environment. A possible pathogenic consequence for these phenomena was demonstrated by abrogation of Fe neuroprotection after pre-exposure of cultures to the Alzheimer's amyloid beta peptide (Abeta). The loss of Fe neuroprotection against reductant toxicity was greater after treatment with human Abeta1-42 than with human Abeta1-40 or rodent Abeta1-42, consistent with the central role of Abeta1-42 in Alzheimer's disease. These findings have important implications for trace biometal interactions and free radical-mediated damage during neurodegenerative illnesses such as Alzheimer's disease and old-age dementia.

Evidence for a possible role for nitric oxide in the modulation of heart activity in Achatina fulica and Helix aspersa

The effects of nitric oxide (NO) donors, S-nitroso-N-acetylpenicillamine, S-nitroso-l-glutathione, sodium nitroprusside and sodium nitrite were investigated on the activity of the isolated hearts of Achatina fulica and Helix aspersa. NO donors inhibited heart activity in a concentration-dependent manner. The only exception was sodium nitroprusside, which excited H. aspersa heart. The inhibitory effects of these NO donors were reduced by the NO scavenger, methylene blue, the guanylyl cyclase inhibitor, 1H-(1,2,4) Oxadiazolo(4,3-a)quinoxalin-1-one (ODQ), and potentiated by 8-Br-cGMP and the phosphodiesterase inhibitor 3-isobutyl-1-methylxanthine (IBMX). Acetylcholine also inhibited the heart activity, and this inhibition was reduced by methylene blue and ODQ. Positive NADPH-diaphorase staining was located in the outer pericardial layer of the heart of A. fulica. The present results provide evidence that NO may modulate the activity of gastropod hearts, and this modulation may modify the inhibitory action of acetylcholine on heart activity.

A review of controlled trials of acupuncture for women's reproductive health care

BACKGROUND

Acupuncture as a therapy, and acupressure as self-treatment, are increasingly widely used for gynaecological conditions, and this study aims to review the scientific literature on their effectiveness.

METHOD

A systematic review of controlled trials of acupuncture or acupressure for gynaecological conditions, published in a European language.

SYNTHESIS

No studies in mastalgia, menorrhagia, pelvic pain, premenstrual syndrome or vulvodynia met the inclusion criteria. Four studies, two of which were patient-blinded, of acupuncture or acupressure for dysmenorrhoea suggest that it may have an effect. Three studies of acupuncture given at various stages of infertility treatment are promising, but none was patient-blind. Two studies of acupuncture for menopausal symptoms showed no effect during the treatment period when compared with sham acupuncture, and a third study showed no effect on hypertension in postmenopausal women, though some improvement in symptoms was noted.

CONCLUSION

In view of the small number of studies and their variable quality, doubt remains about the effectiveness of acupuncture for gynaecological conditions. Acupuncture and acupressure appear promising for dysmenorrhoea, and acupuncture for infertility, and further studies are justified.

Structure of the Alzheimer's disease amyloid precursor protein copper binding domain. A regulator of neuronal copper homeostasis

A major source of free radical production in the brain derives from copper. To prevent metal-mediated oxidative stress, cells have evolved complex metal transport systems. The Alzheimer's disease amyloid precursor protein (APP) is a major regulator of neuronal copper homeostasis. APP knockout mice have elevated copper levels in the cerebral cortex, whereas APP-overexpressing transgenic mice have reduced brain copper levels. Importantly, copper binding to APP can greatly reduce amyloid beta production in vitro. To understand this interaction at the molecular level we solved the structure of the APP copper binding domain (CuBD) and found that it contains a novel copper binding site that favors Cu(I) coordination. The surface location of this site, structural homology of CuBD to copper chaperones, and the role of APP in neuronal copper homeostasis are consistent with the CuBD acting as a neuronal metallotransporter.

Diverse fibrillar peptides directly bind the Alzheimer's amyloid precursor protein and amyloid precursor-like protein 2 resulting in cellular accumulation

The Alzheimer's disease Abeta peptide can increase the levels of cell-associated amyloid precursor protein (APP) in vitro. To determine the specificity of this response for Abeta and whether it is related to cytotoxicity, we tested a diverse range of fibrillar peptides including amyloid-beta (Abeta), the fibrillar prion peptides PrP106-126 and PrP178-193 and human islet-cell amylin. All these peptides increased the levels of APP and amyloid precursor-like protein 2 (APLP2) in primary cultures of astrocytes and neurons. Specificity was shown by a lack of change to amyloid precursor-like protein 1, tau-1 and cellular prion protein (PrP(c)) levels. APP and APLP2 levels were elevated only in cultures exposed to fibrillar peptides as assessed by electron microscopy and not in cultures treated with non-fibrillogenic peptide variants or aggregated lipoprotein. We found that PrP106-126 and the non-toxic but fibril-forming PrP178-193 increased APP levels in cultures derived from both wild-type and PrP(c)-deficient mice indicating that fibrillar peptides up-regulate APP through a non-cytotoxic mechanism and irrespective of parental protein expression. Fibrillar PrP106-126 and Abeta peptides bound recombinant APP and APLP2 suggesting the accumulation of these proteins was mediated by direct binding to the fibrillated peptide. This was supported by decreased APP accumulation following extensive washing of the cultures to remove fibrillar aggregates. Pre-incubation of fibrillar peptide with recombinant APP18-146, the putative fibril binding site, also abrogated the accumulation of APP. These findings show that diverse fibrillogenic peptides can induce accumulation of APP and APLP2 and this mechanism could contribute to pathogenesis in neurodegenerative disorders.

Neurotoxicity from glutathione depletion is dependent on extracellular trace copper

Glutathione (GSH) is an important antioxidant, and its depletion in neurons has been implicated in several neurodegenerative disorders. Aberrant copper metabolism is also implicated in neurodegeneration and may result in the generation of toxic free radicals. However, little is known about the relationship between GSH depletion and copper homeostasis. In the present study, we examined the role of extracellular trace biometals in neuronal cell death induced by GSH depletion. Treatment of primary cortical neurons with buthionine sulfoximine (BSO), an inhibitor of GSH synthesis, induced a rapid loss of intracellular GSH, leading to decreased neuronal cell viability. Neuronal cell death induced by GSH depletion was dependent on trace levels of extracellular copper in the culture medium (1.6 microM). Neurons were protected against GSH depletion-mediated toxicity when cultured in Chelex 100-treated medium containing tenfold less copper (0.16 microM) than normal medium. The addition of copper, but not iron or zinc, to Chelex 100-treated medium restored the neurotoxicity induced by GSH depletion. Moreover, BSO toxicity in normal medium was inhibited by copper chelators. The neurotoxic effects of copper in GSH-depleted neurons involved generation of copper(I) and subsequent free radical-mediated oxidative stress. These studies demonstrate a critical role for extracellular trace copper in neuronal cell death caused by GSH depletion and may have important implications for the understanding of toxic processes in neurodegenerative diseases.

Acetylcholinesterase is increased in mouse neuronal and astrocyte cultures after treatment with beta-amyloid peptides

The cellular origin of the acetylcholinesterase (AChE) associated with amyloid plaques in the Alzheimer's disease (AD) brain is unknown. In this study we report that amyloid beta-peptides (Abeta) increased AChE levels in both neuronal and astrocytic primary cultures, supporting the possibility that both neurons and glia may make a direct contribution to the pool of AChE seen around amyloid deposits in the AD brain.

Monoclonal antibodies inhibit prion replication and delay the development of prion disease

Prion diseases such as Creutzfeldt-Jakob disease (CJD) are fatal, neuro-degenerative disorders with no known therapy. A proportion of the UK population has been exposed to a bovine spongiform encephalopathy-like prion strain and are at risk of developing variant CJD. A hallmark of prion disease is the transformation of normal cellular prion protein (PrP(C)) into an infectious disease-associated isoform, PrP(Sc). Recent in vitro studies indicate that anti-PrP monoclonal antibodies with little or no affinity for PrP(Sc) can prevent the incorporation of PrP(C) into propagating prions. We therefore investigated in a murine scrapie model whether anti-PrP monoclonal antibodies show similar inhibitory effects on prion replication in vivo. We found that peripheral PrP(Sc) levels and prion infectivity were markedly reduced, even when the antibodies were first administered at the point of near maximal accumulation of PrP(Sc) in the spleen. Furthermore, animals in which the treatment was continued remained healthy for over 300 days after equivalent untreated animals had succumbed to the disease. These findings indicate that immunotherapeutic strategies for human prion diseases are worth pursuing.