Toxicity of non-abeta component of Alzheimer's disease amyloid, and N-terminal fragments thereof, correlates to formation of beta-sheet structure and fibrils.

Synucleins are small proteins that are highly expressed in brain tissue and are localised at presynaptic terminals in neurons. alpha-Synuclein has been identified as a component of intracellular fibrillar protein deposits in several neurodegenerative diseases, and two mutant forms of alpha-synuclein have been associated with autosomal-dominant Parkinson's Disease. A fragment of alpha-synuclein has also been identified as the non-Abeta component of Alzheimer's Disease amyloid. In this review we describe some structural properties of alpha-synuclein and the two mutant forms, as well as alpha-synuclein fragments, with particular emphasis on their ability to form beta-sheet on ageing and aggregate to form amyloid-like fibrils. Differences in the rates of aggregation and morphologies of the fibrils formed by alpha-synuclein and the two mutant proteins are highlighted. Interactions between alpha-synuclein and other proteins, especially those that are components of amyloid or Lewy bodies, are considered. The toxicity of alpha-synuclein and related peptides towards neurons is also discussing in relation to the aetiology of neurodegenerative diseases.

Randomized controlled trial of interferential therapy and manipulative therapy for acute low back pain.

Study Design. A multi-center assessor-blinded randomized clinical trial was conducted. Objectives. To investigate the relative effectiveness of interferential therapy and manipulative therapy for patients with acute low back pain when used as sole treatments and in combination. Summary of Background Data. Both manipulative therapy and interferential therapy are commonly used treatments for low back pain. Evidence for the effectiveness of manipulative therapy is available only for the short term. There is no evidence for interferential therapy and no study has investigated the effectiveness of interferential therapy combined with manipulative therapy. Methods. Consenting subjects (n=240) were randomly assigned to receive a copy of the Back Book and either manipulative therapy (MT; n=80), interferential therapy (IFT; n=80) or combined manipulative therapy and interferential therapy (CT; n=80). Follow-up outcome questionnaires were posted at discharge, 6 and 12 months. Results. The groups were balanced at baseline for low back pain and demographic characteristics. All interventions were found to significantly reduce functional disability and pain and increase quality of life at discharge and to maintain these improvements at 6 and 12 months. No significant differences were found between groups for reported LBP recurrence, work absenteeism, medication consumption, exercise participation and healthcare use at 12 months. Conclusions. For acute low back pain, interferential therapy whether used in isolation or in combination with manipulative therapy was as effective as manipulative therapy alone (in addition to the Back Book).

A descriptive study of the usage of spinal manipulative therapy techniques within a randomised clinical trial in acute low back pain

The majority of randomized clinical trials (RCTs) of spinal manipulative therapy have not adequately de?ned the terms ‘mobilization’ and ‘manipulation’, nor distinguished between these terms in reporting the trial interventions. The purpose of this study was to describe the spinal manipulative therapy techniques utilized within a RCT of manipulative therapy (MT; n=80), interferential therapy (IFT; n=80), and a combination of both (CT; n=80) for people with acute low back pain (LBP). Spinal manipulative therapy was de?ned as any ‘mobilization’ (low velocity manual force without a thrust) or ‘manipulation’ (high velocity
thrust) techniques of the spine described by Maitland and Cyriax.
The 16 physiotherapists, all members of the Society of Orthopaedic Medicine, utilized three spinal manipulative therapy patterns in the RCT: Maitland Mobilization (40.4%, n=59), Maitland Mobilization/Cyriax Manipulation (40.4%, n=59) and Cyriax Manipulation (19.1%, n=28). There was a signi?cant difference between the MT and CT groups in their usage of spinal manipulative therapy techniques (w2=9.178; df=2;P=0.01); subjects randomized to the CT group received three times more Cyriax Manipulation (29.2%, n=21/72) than those randomized to the MT group (9.5%, n=7/74; df=1; P=0.003).
The use of mobilization techniques within the trial was comparable with their usage by the general population of physiotherapists in Britain and Ireland for LBP management. However, the usage of manipulation techniques was considerably higher than reported in physiotherapy surveys and may re?ect the postgraduate training of trial therapists.

Why people experiencing acute myocardial infarction delay seeking medical assistance

Background: Delay time from onset of symptoms of myocardial infarction to seeking medical assistance can have life- 31 threatening consequences. A number of factors have been associated with delay, but there is little evidence regarding the predictive 32 value of these indices. Aim: To explore potential predictors of patient delay from onset of symptoms to time medical assistance 33 was sought in a consecutive sample of patients admitted to CCU with acute myocardial infarction. Methods: The Cardiac Denial 34 of Impact Scale, Health Locus of Control Scale, Health Value Scale and Pennebaker Inventory of Limbic Languidness were 35 administered to 62 patients between 3 and 6 days after admission. Results: Attribution of symptoms to heart disease and health 36 locus of control had a significant predictive effect on patients seeking help within 60 min, while previous experience of heart 37 disease did not. Conclusion: Assisting individuals to recognise the potential for symptoms to have a cardiac origin is an important 38 objective. Interventions should take into account the variety of cognitive and behavioural factors involved in decision making.

Higher brain neurons succumb to acute stroke-like insult while lower brain neurons strongly resist

Pyramidal neurons (PyNs) in ‘higher’ brain are highly susceptible to acute stroke injury yet ‘lower’ brain regions better survive global ischemia, presumably because of better residual blood flow. Here we show that projection neurons in ‘lower’ brain regions of hypothalamus and brainstem intrinsically resist acute stroke-like injury independent of blood flow in the brain slice. In contrast `higher` projection neurons in neocortex, hippocampus, striatum and thalamus are highly susceptible. In live brain slices from rat deprived of oxygen and glucose (OGD), we imaged anoxic depolarization (AD) as it propagates through these regions. AD, the initial electrophysiological event of stroke, is a depolarizing front that drains residual energy in compromised gray matter. The extent of AD reliably determines ensuing damage in higher brain, but using whole-cell recordings we found that all CNS neurons do not generate a robust AD. Higher neurons generate strong AD and show no functional recovery in contrast to neurons in hypothalamus and brainstem that generate a weak and gradual AD. Most dramatically, lower neurons recover their membrane potential, input resistance and spike amplitude when oxygen and glucose is restored, while higher neurons do not. Following OGD, new recordings could be acquired in all lower (but not higher) brain regions, with some neurons even withstanding multiple OGD exposure. Two-photon laser scanning microscopy confirmed neuroprotection in lower, but not higher gray matter. Specifically pyramidal neurons swell and lose their dendritic spines post-OGD, whereas neurons in hypothalamus and brainstem display no such injury. Exposure to the Na+/K+ ATPase inhibitor ouabain (100 μM), induces depolarization similar to OGD in all cell types tested. Moreover, elevated [K+]o evokes spreading depression (SD), a milder version of AD, in higher brain but not hypothalamus or brainstem so weak AD correlates with the inability to generate SD. In summary, overriding the Na+/K+ pump using OGD, ouabain or elevated [K+]o evokes steep and robust depolarization of higher gray matter. We show that this important regional difference can be largely accounted for by the intrinsic properties of the resident neurons and that Na+/K+ ATPase pump efficiency is a major determining factor generating strong or weak spreading depolarizations.

Characterization of a thymidylate synthase (TS)-inducible cell line: a model system for studying sensitivity to TS- and non-TS-targeted chemotherapies

Thymidylate synthase (TS) is responsible for the de novo synthesis of thymidylate, which is required for DNA synthesis and repair and which is an important target for fluoropyrimidines such as 5-fluorouracil (5-FU), and antifolates such as Tomudex (TDX), ZD9331, and multitargeted antifolate (MTA). To study the importance of TS expression in determining resistance to these agents, we have developed an MDA435 breast cancer-derived cell line with tetracycline-regulated expression of TS termed MTS-5. We have demonstrated that inducible expression of TS increased the IC(50) dose of the TS-targeted therapeutic agents 5-FU, TDX, and ZD9331 by 2-, 9- and 24-fold respectively. An IC(50) dose for MTA was unobtainable when TS was overexpressed in these cells, which indicated that MTA toxicity is highly sensitive to increased TS expression levels. The growth inhibitory effects of the chemotherapeutic agents CPT-11, cisplatin, oxaliplatin, and Taxol were unaffected by TS up-regulation. Cell cycle analyses revealed that IC(50) doses of 5-FU, TDX and MTA caused an S-phase arrest in cells that did not overexpress TS, and this arrest was overcome when TS was up-regulated. Furthermore, the S-phase arrest was accompanied by 2- to 4-fold increased expression of the cell cycle regulatory genes cyclin E, cyclin A, and cyclin dependent kinase 2 (cdk2). These results indicate that acute increases in TS expression levels play a key role in determining cellular sensitivity to TS-directed chemotherapeutic drugs by modulating the degree of S-phase arrest caused by these agents. Moreover, CPT-11, cisplatin, oxaliplatin, and Taxol remain highly cytotoxic in cells that overexpress TS.

BRCA1 and GADD45 mediated G2/M cell cycle arrest in response to antimicrotubule agents

BRCA1 is a tumour suppressor gene implicated in the predisposition to early onset breast and ovarian cancer. We have generated cell lines with inducible expression of BRCA1 to evaluate its role in mediating the cellular response to various chemotherapeutic drugs commonly used in the treatment of breast and ovarian cancer. Induction of BRCA1 in the presence of Taxol and Vincristine resulted in a dramatic increase in cell death; an effect that was preceded by an acute arrest at the G2/M phase of the cell cycle and which correlated with BRCA1 mediated induction of GADD45. A proportion of the arrested cells were blocked in mitosis suggesting activation of both a G2 and a mitotic spindle checkpoint. In contrast, no specific interaction was observed between BRCA1 induction and treatment of cells with a range of DNA damaging agents including Cisplatin and Adriamycin. Inducible expression of GADD45 in the presence of Taxol induced both G2 and mitotic arrest in these cells consistent with a role for GADD45 in contributing to these effects. Our results support a role for both BRCA1 and GADD45 in selectively regulating a G2/M checkpoint in response to antimicrotubule agents and raise the possibility that their expression levels in cells may contribute to the toxicity observed with these compounds.