Modulation of γ-secretase by EVP-0015962 reduces amyloid deposition and behavioral deficits in Tg2576 mice

Background

A hallmark of Alzheimer’s disease is the presence of senile plaques in human brain primarily containing the amyloid peptides Aβ₄₂ and Aβ₄₀. Many drug discovery efforts have focused on decreasing the production of Aβ₄₂ through γ-secretase inhibition. However, identification of γ-secretase inhibitors has also uncovered mechanism-based side effects. One approach to circumvent these side effects has been modulation of γ-secretase to shift Aβ production to favor shorter, less amyloidogenic peptides than Aβ₄₂, without affecting the overall cleavage efficiency of the enzyme. This approach, frequently called γ-secretase modulation, appears more promising and has lead to the development of new therapeutic candidates for disease modification in Alzheimer’s disease.

Results

Here we describe EVP-0015962, a novel small molecule γ-secretase modulator. EVP-0015962 decreased Aβ₄₂ in H4 cells (IC₅₀ = 67 nM) and increased the shorter Aβ₃₈ by 1.7 fold at the IC₅₀ for lowering of Aβ₄₂. Aβ_Total, as well as other carboxyl-terminal fragments of amyloid precursor protein, were not changed. EVP-0015962 did not cause the accumulation of other γ-secretase substrates, such as the Notch and ephrin A4 receptors, whereas a γ-secretase inhibitor reduced processing of both. A single oral dose of EVP-0015962 (30 mg/kg) decreased Aβ₄₂ and did not alter Aβ_Total peptide levels in a dose-dependent manner in Tg2576 mouse brain at an age when overt Aβ deposition was not present. In Tg2576 mice, chronic treatment with EVP-0015962 (20 or 60 mg/kg/day in a food formulation) reduced Aβ aggregates, amyloid plaques, inflammatory markers, and cognitive deficits.

Conclusions

EVP-0015962 is orally bioavailable, detected in brain, and a potent, selective γ-secretase modulator in vitro and in vivo. Chronic treatment with EVP-0015962 was well tolerated in mice and lowered the production of Aβ₄₂, attenuated memory deficits, and reduced Aβ plaque formation and inflammation in Tg2576 transgenic animals. In summary, these data suggest that γ-secretase modulation with EVP-0015962 represents a viable therapeutic alternative for disease modification in Alzheimer’s disease.

HIV prevalence and sexual behaviour at older ages in rural Malawi

Research on HIV infection and sexual behaviour in sub-Saharan Africa typically focuses on individuals aged 15-49 years under the assumption that both become less relevant for older individuals. We test this assumption using data from rural Malawi to compare sexual behaviour and HIV infection for individuals aged 15-49 with individuals aged 50-64 and 65 and over years. Although general declines with age were observed, levels of sexual activity and HIV remained considerable: 26.7% and 73.8% of women and men aged 65+ reported having sex in the last year, respectively; men's average number of sexual partners remained above one; and HIV prevalence is significantly higher for men aged 50-64 (8.9%) than men aged 15-49 (4.1%). We conclude that older populations are relevant to studies of sexual behaviour and HIV risk. Their importance is likely to increase as access to antiretrovirals in Africa increases. We recommend inclusion of adults aged over 49 years in African HIV/AIDS research and prevention efforts.

Managing Cancer and Living Meaningfully (CALM): a qualitative study of a brief individual psychotherapy for individuals with advanced cancer

BACKGROUND

Although psychosocial care has been regarded as central to palliative and supportive care, there have been few empirically tested approaches to individual intervention.

AIM

The subjective experience of advanced cancer patients receiving a new manualized brief individual psychotherapy, referred to as Managing Cancer and Living Meaningfully (CALM), was examined prior to the initiation of a randomized controlled trial testing the effectiveness of this intervention.

DESIGN

Semi-structured interviews were conducted with patients who had a diagnosis of advanced cancer, and who underwent the intervention.

SETTING/PARTICIPANTS

Patients were recruited from a large urban regional cancer center in Toronto, Canada. The 10 interviewees included seven women and three men. All had completed between three to six CALM sessions prior to the interview.

RESULTS

The CALM intervention was associated with profound and unique patient-identified benefits and no patient-identified risks or concerns. Five interrelated benefits of the intervention were identified: (1) a safe place to process the experience of advanced cancer; (2) permission to talk about death and dying; (3) assistance in managing the illness and navigating the healthcare system; (4) resolution of relational strain; and (5) an opportunity to 'be seen as a whole person' within the healthcare system. These benefits were regarded by participants as unique in their cancer journey.

CONCLUSIONS

Findings from a qualitative study suggest that the CALM intervention provides substantial benefits for patients with advanced cancer prior to the end of life. Findings informed the development of a randomized controlled trial to evaluate the effectiveness of this intervention.

The evidence-based medicine model of clinical practice: scientific teaching or belief-based preaching?

RATIONALE

Evidence-based medicine (EBM) is commonly advocated as a 'gold standard' of clinical practice. A prominent definition of EBM is: the integration of best research evidence with clinical expertise and patient values. Over time, various versions of a conceptual model or framework for implementing EBM (i.e. how to practice EBM) have been developed.

AIMS AND OBJECTIVES

This paper (i) traces the evolution of the different versions of the conceptual model; (ii) tries to make explicit the underlying goals, assumptions and logic of the various versions by exploring the definitions and meaning of the components identified in each model, and the methods suggested for integrating these into clinical practice; and (iii) offers an analytic critique of the various model iterations.

METHODS

A literature review was undertaken to identify, summarize, and compare the content of articles and books discussing EBM as a conceptual model to guide physicians in clinical practice.

RESULTS

Our findings suggest that the EBM model of clinical practice, as it has evolved over time, is largely belief-based, because it is lacking in empirical evidence and theoretical support. The model is not well developed and articulated in terms of defining model components, justifying their inclusion and suggesting ways to integrate these in clinical practice.

CONCLUSION

These findings are significant because without a model that clearly defines what constitutes an EBM approach to clinical practice we cannot (i) consistently teach clinicians how to do it and (ii) evaluate whether it is being done.

Thermal stabilization of tissues and the preservation of protein phosphorylation states for two-dimensional gel electrophoresis

2-DE is typically capable of discriminating proteins differing by a single phosphorylation or dephosphorylation event. However, a reliable representation of protein phosphorylation states as they occur in vivo requires that both phosphatases and kinases are rapidly and completely inactivated. Thermal stabilization of mouse cerebral cortex homogenates effectively inactivated these enzymes, as evidenced by comparison with unstabilized tissues where abscissal pI shifts were a common feature in 2-D gels. Of the 588 matched proteins separated on 2-D gels comparing stabilized and unstabilized tissues, 53 proteins exhibited greater than twofold differences in spot volume (ANOVA, p<0.05). Phosphoprotein-specific staining was corroborated by the identification of 16 phosphoproteins by nano-LC MS/MS and phosphotyrosine kinase activity assay.

The responses of professional groups to the use of Section 136 of the Mental Health Act (1983, as amended by the 2007 Act) in Gloucestershire

BACKGROUND

Section 136 (S136) of the Mental Health Act (1983, as amended by the 2007 Act) empowers the police to detain those suspected of being mentally disordered in a public place and to convey them to a place of safety (POS) for further assessment. Gloucestershire has not had a specialist facility for S136 detentions and individuals were taken to the police cells or occasionally A&E departments for assessment.

AIMS

This paper forms one part of three aspects under investigation. Two companion papers by the authors describe the use of S136 using anonymised audit data and the experiences of detainees. The objectives of this paper have been to assess the responses of the different professional groups involved in the process of S136.

METHOD

An anonymous postal questionnaire was distributed to eight groups of professionals who were identified as having the potential to be involved in part of the process of a S136 detention. Results were collated and analysed, and formed the basis for a series of follow-up focus groups within groups to explore themes that warranted further investigation.

RESULTS

An overall response rate of 59% was achieved. Seventy-four per cent of participants thought that there should be an alternative POS to the police station. A&E was thought to be an unsuitable alternative POS, with a psychiatric hospital being the first choice for 58%.

CONCLUSIONS

There is a gap in the expectations of the different agencies involved in the S136 process, which have the potential to be divisive if interagency pathways and agreements are not in place.

Weight Gain Is Associated with Increased Risk of Hot Flashes in Breast Cancer Survivors on Aromatase Inhibitors

Objective: Hot flashes in breast cancer survivors (BCS) receiving adjuvant aromatase inhibitor (AI) therapy are common, but risk factors for these symptoms are not well-defined. This study tested if body size is associated with hot flashes in BCS on AI therapy.Materials and methods: We performed a cross-sectional analysis of a cohort of postmenopausal women with Stages 0-III breast cancer receiving adjuvant AI therapy at a university hospital-based outpatient breast oncology clinic. Subjects provided patient-reported outcomes on hot flashes, current and pre-breast cancer weight and height, and additional demographic and treatment data.The primary outcome was occurrence of hot flashes. Secondary outcomes included hot flash severity and frequency. The exposures of interest were 1) current weight and 2) weight change since breast cancer diagnosis, categorized as weight loss (lost 10 pounds or more), maintenance (+/- 10 pounds), or gain (gained 10 pounds or more). Multivariable logistic regression models examined the independent association between hot flash outcomes and current weight or weight change while controlling for confounders.Results: 300 participants were enrolled at a mean age of 61 years (range 33-86) after mean duration of AI exposure of 23 months (range 1 month-9 years). 177 (59%) reported hot flashes overall, 96 (32%) reported moderate to very severe hot flashes, and 60 (20%) had at least 4 hot flashes daily. 182 (61%) experienced weight maintenance, while 81 (27%) had weight gain and 34 (11%) had weight loss. In a multivariable model, weight gain was independently associated with hot flash occurrence (OR 2.1, 95% CI 1.1-4.4) and hot flash severity (OR 2.4, 95% CI 1.4-4.9), but not hot flash frequency, after adjusting for current weight and height, age, smoking, race, prior chemotherapy and prior tamoxifen therapy. Hot flash occurrence was also significantly associated with current smoking (OR 5.1, 95% CI 1.1-24.0) and age (OR for each additional year of age 0.93, 95% CI 0.90-0.97). Current weight, alcohol use, AI type, and AI duration were not associated with any of the three outcomes.Conclusions: In an outpatient BCS population on AI therapy, weight gain is a risk factor for both hot flash occurrence and severity. Women who gained at least ten pounds since breast cancer diagnosis were two times more likely to have hot flashes than women who maintained or lost weight. These results support the thermoregulatory model of hot flashes and argue against a protective effect of body fat in this population.Support: ACS MRSG-08-110-01-CCE, ACS CCDA#-08-107-01, Pennsylvania Department of Aging

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 1059.

Dynamic position and force measurement for multiple optically trapped particles using a high-speed active pixel sensor

A high frame rate active pixel sensor designed to track the position of up to six optically trapped objects simultaneously within the field of view of a microscope is described. The sensor comprises 520 x 520 pixels from which a flexible arrangement of six independent regions of interest is accessed at a rate of up to 20 kHz, providing the capability to measure motion in multiple micron scale objects to nanometer accuracy. The combined control of both the sensor and optical traps is performed using unique, dedicated electronics (a field programmable gate array). The ability of the sensor to measure the dynamic position and the forces between six optically trapped spheres, down to femtonewton level, is demonstrated paving the way for application in the physical and life sciences.

Strategies used to increase chlamydia screening in general practice: a qualitative study

OBJECTIVES

To explore strategies used by chlamydia screening co-ordinators and practice staff to implement genital chlamydia screening within general practices.

METHODS

Qualitative phenomenological study using individual semi-structured telephone interviews. Screening co-ordinators were selected purposively in Phase 1 and 2 areas of the Department of Health National Chlamydia Screening Programme in England, where there was significant screening in general practice. Open questions were asked about: the factors that determined high chlamydia screening rates; maintaining motivation for screening; and strategies to increase screening in general practices.

RESULTS

Co-ordinators reported that successful screening practices had a champion who drove the screening process forward. These practices had normalized screening, so all at-risk patients were offered opportunistic screening whenever they attended. This was facilitated by a variety of time-saving methods including computer prompts, test kits in the reception area, youth clinics and receptionist involvement. Chlamydia screening was sustained through frequent reminders, newsletters containing chlamydia screening rates, and advertising to the 'at-risk' population from the screening team. Co-ordinators' enthusiasm and project management skills were as important as sexual health experience. Co-ordinators reported that to facilitate chlamydia screening across all practices, screening could be included in the General Medical Services (GMS) contract, and a higher national profile was needed amongst health professionals and the public.

CONCLUSIONS

All practice staff need to be encouraged to become champions of the chlamydia screening programme through education, especially aimed at older clinicians and receptionists. The National Health Service should consider including chlamydia screening in the GMS contract. Increased public awareness will allow screening to be undertaken more quickly and by non-medical staff.

Tissue fractionation by hydrostatic pressure cycling technology: the unified sample preparation technique for systems biology studies

Major bottlenecks in systems biology studies arise from limitations of current sample preparation techniques. Multiple mutually exclusive sample preparation methods, which are often required to extract distinct classes of molecules from cells and tissues, are incompatible with studies of precious or very limited samples. Moreover, the strong detergents and chaotropic agents commonly required to solubilize sample constituents often interfere with subsequent separation and analysis. Here we describe a rapid, detergent-free sample preparation technique that allows efficient concurrent isolation and fractionation of protein, DNA, RNA, and lipids from biological samples, eliminating the need for multiple replicates. The method relies on a synergistic combination of physical disruption of the cellular material by hydrostatic pressure (pressure cycling technology) and novel extraction conditions to dissolve and partition distinct classes of molecules into separate fractions. We demonstrate parallel recovery of proteins, lipids, and intact DNA and RNA, from animal cells and tissues, for proteomic, lipidomic, and genomic analyses. The protein extracts require minimal cleanup and are compatible with 1D and 2D PAGE, liquid chromatography coupled with tandem mass spectrometry, and Western blotting. The lipid fractions have been profiled by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry without further processing. The isolated DNA and RNA were shown to be intact by agarose gel visualization, and the presence of intact mRNA was confirmed by real time reverse transcription polymerase chain reaction. Analysis and comparison of samples extracted using this method and a more traditional extraction technique revealed several protein species preferentially extracted by the new method.

Clinical relevance of laboratory-reported antibiotic resistance in acute uncomplicated urinary tract infection in primary care

OBJECTIVES

To determine whether patients with an uncomplicated community-acquired urinary tract infection (UTI) and an isolate resistant to trimethoprim had worse clinical outcomes following empirical treatment with trimethoprim 200 mg twice daily for 3 days than did those with a susceptible isolate.

PATIENTS AND METHODS

This was a prospective cohort study of clinical outcome. We enrolled 497 women (>or=18-70 years) presenting to general practitioner surgeries in Norwich and Gloucester with at least two symptoms of acute (<7 days) uncomplicated UTI. Significant bacteriuria was defined as >or=10(4) cfu/mL from a mid-stream urine (MSU).

RESULTS

Of enrolled patients 75% (334/448) had significant bacteriuria, and trimethoprim resistance was present in 13.9% (44/317) of isolates. Patients with resistant isolates had a longer median time to symptom resolution (7 versus 4 days, P=0.0002), greater reconsultation to the practice (39% versus 6% in first week, P<0.0001), more subsequent antibiotics (36% versus 4% in first week, P<0.0001) and higher rates of significant bacteriuria at 1 month (42% versus 20% with susceptible isolate, P=0.04). Half of patients reconsulting in the first week had a resistant organism.

CONCLUSIONS

Patients with uncomplicated UTI caused by trimethoprim-resistant organisms had significantly worse clinical outcomes than those with trimethoprim-susceptible organisms. Nevertheless, trimethoprim resistance was rarer than predicted from routine laboratory submissions and we calculate that 23 women require microbiological investigation to prevent one reconsultation arising from resistance-based treatment failure. We therefore suggest empirical antibiotic treatment in acute, uncomplicated UTIs. If patients reconsult in the first week, we suggest a change of antibiotic treatment with urine culture and susceptibility testing then done. More generally, laboratory resources should concentrate on resistance surveillance to inform empirical antibiotic choice.

Interactions between attention and perceptual grouping in human visual cortex

Freeman et al. demonstrated that detection sensitivity for a low contrast Gabor stimulus improved in the presence of flanking, collinearly oriented grating stimuli, but only when observers attended to them. By recording visual event-related potentials (ERPs) elicited by a Gabor stimulus, we investigated whether this contextual cueing effect involves changes in the short-latency afferent visual signal from V1 that have a stimulus onset latency between 60 and 80 ms and/or longer-latency changes from visual cortex. Under dual-task conditions, the subjects performed contrast discrimination for a central Gabor and an orientation judgment for a pre-specified subset of the flanking Gabors. On random trials, the central Gabor could be collinearly or orthogonally oriented with respect to the attended flankers. Subjects showed improvements in discriminating the contrast of the central grating when it was oriented collinearly with the attended flankers. The ERP difference between attending to collinear versus orthogonal flankers manifested as a positive polarity response at occipital electrodes with a latency of 180-250 ms after stimulus onset. No shorter-latency contextual cueing differences were observed in the ERPs. The ERP latency profile of the contextual cueing effect argues against the hypothesis that short-latency afferent activity from V1 is the stage of processing at which attention can influence neuronal lateral interactions. However, the scalp voltage distribution of the longer-latency contextual cueing effect is similar to the one generated by the early phasic stimulus onset activity from V1. These findings leave open the possibility that V1 is involved in the attentional modulation of lateral interactions but that this has a longer time course, likely being mediated by re-afferent inputs from later stages of the visual pathway.