Clinical effectiveness of alcohol-based products in increasing hand hygiene compliance and reducing infection rates: a systematic review

Reducing the incidence of healthcare-associated infection represents a major challenge. This systematic review of the evidence base considers the clinical effectiveness of incorporating an alcohol-based hand hygiene product into procedures aimed at improving compliance with hand hygiene guidelines, and thereby reducing the incidence of healthcare-associated infections. Multi-component interventions that included alcohol-based products were as effective as those that did not, both in achieving sustained hand hygiene compliance and in reducing infection rates. However, a number of difficulties were encountered in assessing hand hygiene studies: the problem of attributing efficacy to an alcohol-based product when used in a multi-component intervention; the variability inherent in the design of such studies; and how to use data from uncontrolled, unblinded studies in the assessment.

Characteristics of undiagnosed diabetes in community-dwelling French elderly: the 3C study

We aimed to assess clinical and socio-demographic characteristics of undiagnosed diabetes, including glucose control, in French community-living elderly people. Diagnosed and undiagnosed diabetes, impaired fasting glucose (IFG) and characteristics of subjects were assessed by interview, clinical examination and fasting blood glucose measures at the baseline visit of the Three-City (3C) study including 9294 people over 65 in three urban areas in France. In the Bordeaux sample, HbA1c was measured in diabetic and IFG subjects and in a sub-sample of non-diabetic subjects. The proportion of diagnosed diabetes, undiagnosed diabetes and IFG was, respectively, 8.2%, 1.4% and 3.6%. Diabetic and IFG subjects were more likely to be men, to suffer from hypertension and to be overweight. They were less likely to have a high income and more likely to have a lower educational level. These factors were unrelated to knowledge of diabetic status. In the Bordeaux sub-sample, 19.6% of the diagnosed diabetic subjects and 16.1% of those undiagnosed had an HbA1c greater than 8%. Prevalence of ischemic heart disease was more common in diagnosed than in undiagnosed diabetic subjects (P=.021). A significant number of undiagnosed elderly had poor glucose control suggesting a potential benefit for diabetes screening in the elderly.

Dynamics of neutrophil membrane compliance and microstructure probed with a micropipet-based piconewton force transducer

A novel biointerface probe was implemented to study the deformability of the neutrophil membrane and cortical cytoskeleton. Piconewton scale forces are applied to the cell using an ultrasensitive and tunable force transducer comprised of an avidin-coated microsphere attached to a biotinylated and swollen red blood cell. Deformations of freshly isolated human neutrophils were observed on the stage of an inverted phase contrast microscope. Force versus probe indentation curves over a cycle of contact, indentation, and retraction revealed three distinct material responses. Small probe deformations (approximately 500 nm) tested over a range of rates (e.g. 100-500 nm/s) revealed predominantly an elastic response. An initial low-slope region in the force-indentation curves (approximately 0.005 pN/nm), typically extending 0.5-1.0 microm from the cell surface was interpreted as probe contact with microvilli extensions. Further deformation yielded a slope of 0.054+/-0.006 pN/nm, indicative of a stiffer cortical membrane. Disrupting cytoskeletal actin organization by pretreatment with cytochalasin D, reduced the slope by 40% to 0.033+/-0.007 pN/nm and introduced hysteresis in the recovery phase. Modeling the neutrophil as a liquid drop with constant surface tension yielded values of cortical tension of 0.035 pN/nm for resting and 0.02 pN/nm for cytochalasin-treated neutrophils. These data demonstrate the utility of the biointerface probe for measuring local surface compliance and microstructure of living cells.

Single molecule studies of molecular diffusion in cellular membranes: Determining membrane structure

Since the advent of single particle/molecule microscopies, researchers have applied these techniques to understanding the fluid membranes of cells. By observing diffusion of membrane proteins and lipids in live cell membranes of eukaryotic cells, it has been found that membranes contain a mosaic of fluid compartments. Such structure may be instrumental in understanding key characteristics of the membrane. Recent single molecule observations on prokaryotic cell membranes will also be discussed.

Life-time history of suicide attempts and coronary artery disease in a community-dwelling elderly population

BACKGROUND

Numerous studies have observed a strong relationship between coronary artery disease (CAD) and psychiatric disorder; notably depression, anxiety and panic attacks. No study has, however, explored the question of whether persons suffering from CAD might also be at high risk of suicide attempts.

OBJECTIVE

The aim of the present study is to examine the relationship between CAD within a general population cohort and life-time history of psychiatric disorder and suicidal behaviour.

METHOD

A representative sample of 1,843 non-institutionalized persons over 65, drawn at random from the electoral roll, was given a standardized neurological and psychiatric examination based on DSM-IV criteria. The clinical examination also included an electrocardiogram (ECG) and a questionnaire relating to life-time medical history. Cardiac events were validated by the general practitioner.

RESULTS

Within this general population sample the prevalence of suicide attempts was 3.9%. A significant positive association was observed between life-time prevalence of CAD and suicide attempts (p<0.04). Suicide attempts were associated with major depression (p<0.001) co-morbid anxiety and depression (p<0.001) but not anxiety alone (p=0.16). A logistic regression analysis showed that the relationship between suicide attempts and CAD persists after adjustment for depression and anxiety.

CONCLUSION

CAD is associated with suicidal behaviour independently of depression, however, longitudinal studies are required to clarify the direction of causality and to integrate genetic, biological, environmental and psychological factors into an aetiological model.

APOE genotype, cholesterol level, lipid-lowering treatment, and dementia: the Three-City Study

OBJECTIVE

To examine the association of plasma cholesterol levels, lipid-lowering agent (LLA) intake, and APOE genotype with dementia prevalence.

METHODS

The Three-City Study is a population-based cohort of 9,294 subjects selected from the electoral rolls of three French cities (Bordeaux, Dijon, Montpellier). Baseline examination included extensive assessment of exposure to vascular risk factors (including cholesterol levels and LLA use [statin or fibrate]) and clinical diagnosis of dementia.

RESULTS

Two percent of participants were demented at baseline. Overall 32.4% of participants had hyperlipidemia, and 15.6% were prescribed statins and 13.7% fibrates. After adjusting for age, gender, education level, and study center, the odds ratio (OR) for dementia was observed to be lower among LLA users (OR = 0.61, 95% CI = 0.41 to 0.91) compared with subjects taking no LLAs. There was no differential effect between statin and fibrate users. The odds for dementia were increased in subjects with hyperlipidemia (OR = 1.43, 95% CI = 1.03 to 1.99). Further adjustment for potential confounders did not modify these associations. In addition, the association between LLA intake and dementia was not modified by APOE genotype, whereas hyperlipidemia was significantly associated with increased dementia prevalence only in non-epsilon4 carriers and non-Alzheimer disease cases. Finally, in participants taking LLAs, the odds for dementia were decreased only in those having normal lipid levels.

CONCLUSIONS

This observational study provides further evidence that lipid-lowering agents are associated with decreased risk of dementia, whereas hyperlipidemia is associated with increased odds for non-Alzheimer-disease-type dementia. These effects appear to be independent of all major potential confounders.

Le test des 5 mots : validité dans la détection de la maladie d’Alzheimer dans la population générale

INTRODUCTION

In general medicine lack of time impairs screening for Alzheimer's disease (AD). The five word test (FWT) enables rapid assessment of verbal episodic memory in accordance with Grober and Buschke neuropsychological concept. The main steps of the FWT are: induce specific semantic processing, control of encoding to avoid attention deficits, free and cued recall. Cued recall helps to distinguish a recall impairment from storage impairment which is evocative of AD.

OBJECTIVE

Evaluate FWT total score (sum of free and cued recalls), FWT total weighed score which give a higher coefficient for free recalls than cued recalls and present the ability of these two scores for AD screening.

METHOD

Evaluation performed with 4116 subjects (of whom 73 MA) aged from 65 years and more, randomly selected in two French towns for the "Three Cities" Study, a population-based cohort.

RESULTS

The total score was more specific than sensitive with a maximal sensitivity (Se) at 63 percent with specificity (Sp) at 91.1 percent. The total weighed score significantly increased Se (83.6 percent) with control of specificity (84.9 percent) and positive predictive value (9.1 percent).

CONCLUSION

The FWT allows quick screening of patients for whom further neuropsychological evaluation is needed to diagnose AD. The ability of is simple test to screen for AD is improved by a simple weighting procedure: the total weighted score.

Lifelong Endocrine Fluctuations and Related Cognitive Disorders

The aim of this review is to examine the relationship between endocrine fluctuation and cognitive functioning. A plethora of in vitro and in vivo studies has demonstrated the neuroprotective role of estrogens and their impact on the neurotransmitter systems implicated in cognition. Recent hormonal replacement therapy (HRT) trials in non-demented post-menopausal women suggest a temporary positive effect (notably on verbal memory), and four recent meta-analyses converge to suggest a possible protective effect in relation to Alzheimer's disease (reducing risk by 29 to 44%). However, data from the only large randomised controlled trial published to date, the Women's Health Initiative Memory Study, did not confirm these observations and have even suggested an increase in dementia risk for women using HRT compared to controls. Several methodological differences between observation studies and controlled trials with regard to patient group, type, timing and duration of HRT, cognitive measures and analyses, are discussed to explain these discrepancies. The association between hormonal serum level and cognitive functioning remains controversial suggesting high inter-individual vulnerability in risk. Moreover, research on the impact of endocrine functioning on cognition during the female reproductive cycle suggests life-long fluctuations in vulnerability. Etiological models taking into account the interaction of clinical, reproductive, and menstrual events throughout life may provide a more valid approach in understanding the effects of steroids on the brain and in determining sub-groups at heightened risk. Cognitive disorders in the elderly are more likely be related to cumulated lifelong exposure to steroids, rather than to a specific exposure to a given steroid. Multifactorial models based on an exhaustive view of all hormonal events throughout reproductive life together with other risk factors (notably genetic risk factors related to estrogen receptor polymorphisms) should be explored to clarify the role of hormonal risk factors, or protective factors for cognitive dysfunction and dementia.

Economic modelling of antenatal screening and ultrasound scanning programmes for identification of fetal abnormalities

OBJECTIVE

Within the framework of a health technology assessment and using an economic model, to determine the most clinically and cost effective policy of scanning and screening for fetal abnormalities in early pregnancy.

DESIGN

A discrete event simulation model of 50,000 singleton pregnancies.

SETTING

Maternity services in Scotland.

POPULATION

Women during the first 24 weeks of their pregnancy.

METHODS

The mathematical model was populated with data on uptake of screening, prevalence, detection and false positive rates for eight fetal abnormalities and with costs for ultrasound scanning and serum screening. Inclusion of abnormalities was based on the relative prevalence and clinical importance of conditions and the availability of data. Six strategies for the identification of abnormalities prenatally including combinations of first and second trimester ultrasound scanning and first and second trimester screening for chromosomal abnormalities were compared.

MAIN OUTCOME MEASURES

The number of abnormalities detected and missed, the number of iatrogenic losses resulting from invasive tests, the total cost of strategies and the cost per abnormality detected were compared between strategies.

RESULTS

First trimester screening for chromosomal abnormalities costs more than second trimester screening but results in fewer iatrogenic losses. Strategies which include a second trimester ultrasound scan result in more abnormalities being detected and have lower costs per anomaly detected.

CONCLUSIONS

The preferred strategy includes both first and second trimester ultrasound scans and a first trimester screening test for chromosomal abnormalities. It has been recommended that this policy is offered to all women in Scotland.

Prevalence of dementia in the elderly in Europe

Dementia is an important public health problem as it is one of the most common diseases in the elderly and a major cause of disability and mortality. This review on dementia is restricted to European Union countries where the overwhelming majority of studies have been undertaken, and will also refer to the EURODEM publications which may be considered to be the principal European reference point in this area. In subjects aged over 65, crude prevalence rates for dementia varied between 5.9% and 9.4%. We discuss the major problems limiting the use of these estimations, limits which may differ according to the area of application, be it etiological research or care provision.

Paradigm shift of the plasma membrane concept from the two-dimensional continuum fluid to the partitioned fluid: high-speed single-molecule tracking of membrane molecules

Recent advancements in single-molecule tracking methods with nanometer-level precision now allow researchers to observe the movement, recruitment, and activation of single molecules in the plasma membrane in living cells. In particular, on the basis of the observations by high-speed single-particle tracking at a frame rate of 40,000 frames s(1), the partitioning of the fluid plasma membrane into submicron compartments throughout the cell membrane and the hop diffusion of virtually all the molecules have been proposed. This could explain why the diffusion coefficients in the plasma membrane are considerably smaller than those in artificial membranes, and why the diffusion coefficient is reduced upon molecular complex formation (oligomerization-induced trapping). In this review, we first describe the high-speed single-molecule tracking methods, and then we critically review a new model of a partitioned fluid plasma membrane and the involvement of the actin-based membrane-skeleton "fences" and anchored-transmembrane protein "pickets" in the formation of compartment boundaries.

Rapid hop diffusion of a G-protein-coupled receptor in the plasma membrane as revealed by single-molecule techniques

Diffusion of a G-protein coupled receptor, mu-opioid receptor (muOR), in the plasma membrane was tracked by single-fluorescent molecule video imaging and high-speed single-particle tracking. At variance with a previous publication, where gold-tagged muOR was found to be totally confined within a domain, which in turn underwent very slow diffusion itself, we found that muOR undergoes rapid hop diffusion over membrane compartments (210-nm and 730-nm nested double compartments in the case of normal rat kidney cell line), which are likely delimited by the actin-based membrane-skeleton "fence or corrals" and its associated transmembrane protein "pickets", at a rate comparable to that for transferrin receptor (every 45 and 760 ms on average, respectively), suggesting that the fence and picket models may also be applicable to G-protein coupled receptors. Further, we found that strong confinement of gold-labeled muOR could be induced by the prolonged on-ice preincubation of the gold probe with the cells, showing that this procedure should be avoided in future single-particle tracking experiments. Based on the dense, long trajectories of muOR obtained by high-speed single-particle tracking, the membrane compartments apposed and adjoined to each other could be defined that are delimited by rather straight boundaries, consistent with the involvement of actin filaments in membrane compartmentalization.

Ultrafine membrane compartments for molecular diffusion as revealed by single molecule techniques

Plasma membrane compartments, delimited by transmembrane proteins anchored to the membrane skeleton (anchored-protein picket model), would provide the membrane with fundamental mosaicism because they would affect the movement of practically all molecules incorporated in the cell membrane. Understanding such basic compartmentalized structures of the cell membrane is critical for further studies of a variety of membrane functions. Here, using both high temporal-resolution single particle tracking and single fluorescent molecule video imaging of an unsaturated phospholipid, DOPE, we found that plasma membrane compartments generally exist in various cell types, including CHO, HEPA-OVA, PtK2, FRSK, HEK293, HeLa, T24 (ECV304), and NRK cells. The compartment size varies from 30 to 230 nm, whereas the average hop rate of DOPE crossing the boundaries between two adjacent compartments ranges between 1 and 17 ms. The probability of passing a compartment barrier when DOPE is already at the boundary is also cell-type dependent, with an overall variation by a factor of approximately 7. These results strongly indicate the necessity for the paradigm shift of the concept on the plasma membrane: from the two-dimensional fluid continuum model to the compartmentalized membrane model in which its constituent molecules undergo hop diffusion over the compartments.

Detection of non-Brownian diffusion in the cell membrane in single molecule tracking

Molecules undergo non-Brownian diffusion in the plasma membrane, but the mechanism behind this anomalous diffusion is controversial. To characterize the anomalous diffusion in the complex system of the plasma membrane and to understand its underlying mechanism, single-molecule/particle methods that allow researchers to avoid ensemble averaging have turned out to be highly effective. However, the intrinsic problems of time-averaging (resolution) and the frequency of the observations have not been explored. These would not matter for the observations of simple Brownian particles, but they do strongly affect the observation of molecules undergoing anomalous diffusion. We examined these effects on the apparent motion of molecules undergoing simple, totally confined, or hop diffusion, using Monte Carlo simulations of particles undergoing short-term confined diffusion within a compartment and long-term hop diffusion between these compartments, explicitly including the effects of time-averaging during a single frame of the camera (exposure time) and the frequency of observations (frame rate). The intricate relationships of these time-related experimental parameters with the intrinsic diffusion parameters have been clarified, which indicated that by systematically varying the frame time and rate, the anomalous diffusion can be clearly detected and characterized. Based on these results, single-particle tracking of transferrin receptor in the plasma membrane of live PtK2 cells were carried out, varying the frame time between 0.025 and 33 ms (0.03-40 kHz), which revealed the hop diffusion of the receptor between 47-nm (average) compartments with an average residency time of 1.7 ms, with the aid of single fluorescent-molecule video imaging.

Fluorescence imaging for monitoring the colocalization of two single molecules in living cells

The interaction, binding, and colocalization of two or more molecules in living cells are essential aspects of many biological molecular processes, and single-molecule technologies for investigating these processes in live cells, if successfully developed, would become very powerful tools. Here, we developed simultaneous, dual-color, single fluorescent molecule colocalization imaging, to quantitatively detect the colocalization of two species of individual molecules. We first established a method for spatially correcting the two full images synchronously obtained in two different colors, and then for overlaying them with an accuracy of 13 nm. By further assessing the precision of the position determination, and the signal/noise and signal/background ratios, we found that two single molecules in dual color can be colocalized to within 64-100 nm (68-90% detectability) in the membrane of cells for GFP and Alexa633. The detectability of true colocalization at the molecular level and the erroneous inclusion of incidental approaches of two molecules as colocalization have to be compromised at different levels in each experiment, depending on its purpose. This technique was successfully demonstrated in living cells in culture, monitoring colocalization of single molecules of E-cadherin fused with GFP diffusing in the plasma membrane with single molecules of Alexa633 conjugated to anti-E-cadherin Fab externally added to the culture medium. This work established a benchmark for monitoring the colocalization of two single molecules, which can be applied to wide ranges of studies for molecular interactions, both at the levels of single molecules and collections of molecules.

Mild cognitive impairment--beyond controversies, towards a consensus: report of the International Working Group on Mild Cognitive Impairment

The First Key Symposium was held in Stockholm, Sweden, 2-5 September 2003. The aim of the symposium was to integrate clinical and epidemiological perspectives on the topic of Mild Cognitive Impairment (MCI). A multidisciplinary, international group of experts discussed the current status and future directions of MCI, with regard to clinical presentation, cognitive and functional assessment, and the role of neuroimaging, biomarkers and genetics. Agreement on new perspectives, as well as recommendations for management and future research were discussed by the international working group. The specific recommendations for the general MCI criteria include the following: (i) the person is neither normal nor demented; (ii) there is evidence of cognitive deterioration shown by either objectively measured decline over time and/or subjective report of decline by self and/or informant in conjunction with objective cognitive deficits; and (iii) activities of daily living are preserved and complex instrumental functions are either intact or minimally impaired.

Neuroanatomical localisation and clinical correlates of white matter lesions in the elderly

BACKGROUND

White matter lesions (WML) in elderly people co-occur with hypertension, depression, and cognitive impairment. Little is known about the density and distribution of WML in normal elderly people, whether they occur randomly in the aging brain or tend to cluster in certain areas, or whether patterns of WML aggregation are linked to clinical symptoms.

OBJECTIVES

To describe patterns of WML distribution in a large representative population of elderly people using non-inferential cluster analysis; and to determine the extent to which such patterns are associated with clinical symptomatology.

METHOD

A population sample of 1077 elderly people was recruited. Multiple analysis of correspondence followed by automatic classification methods was used to explore overall patterns of WML distribution. Correspondence was then sought between these patterns and a range of cerebrovascular, psychiatric, and neurological symptoms.

RESULTS

Three distinct patterns of spatial localisation within the brain were observed, corresponding to distinct clusters of clinical symptoms. In particular WML aggregation in temporal and occipital areas was associated with greater age, hypertension, late onset depressive disorder, poor global cognitive function, and overall WML frequency.

CONCLUSIONS

WML localisation is not random in the aging brain, and their distribution is associated with age and the presence of clinical symptoms. Age differences suggest there may be patterns of progression across time; however, this requires confirmation from longitudinal imaging studies.

Mild cognitive impairment--beyond controversies, towards a consensus: report of the International Working Group on Mild Cognitive Impairment

The First Key Symposium was held in Stockholm, Sweden, 2-5 September 2003. The aim of the symposium was to integrate clinical and epidemiological perspectives on the topic of Mild Cognitive Impairment (MCI). A multidisciplinary, international group of experts discussed the current status and future directions of MCI, with regard to clinical presentation, cognitive and functional assessment, and the role of neuroimaging, biomarkers and genetics. Agreement on new perspectives, as well as recommendations for management and future research were discussed by the international working group. The specific recommendations for the general MCI criteria include the following: (i) the person is neither normal nor demented; (ii) there is evidence of cognitive deterioration shown by either objectively measured decline over time and/or subjective report of decline by self and/or informant in conjunction with objective cognitive deficits; and (iii) activities of daily living are preserved and complex instrumental functions are either intact or minimally impaired.

Relationship between body mass index and different domains of disability in older persons: the 3C study

OBJECTIVE

To study the relationships between body mass index (BMI) and different domains of disability in elderly subjects from the French 3C study.

SETTING

Three cities in France: Bordeaux (South-West), Dijon (North-East) and Montpellier (South-East).

DESIGN

Cross-sectional study.

SUBJECTS

A sample of 8966 elderly community dwellers (age: 65-101 y).

MEASUREMENTS

MAIN OUTCOME MEASURES

BMI, continence, basic and Instrumental Activities of Daily Living (ADL and IADL) and mobility. Adjustment variables: age, educational level, lifestyle, cognitive functioning, smoking and drinking history, depression, dyspnea, diabetes and indicator of cardiovascular disease.

RESULTS

Obesity (BMI> or =30 kg/m2) was significantly associated with disability in each domain for women. The relationship tended to be linear for ADL and for continence; whereas for IADL, underweight women (BMI <21 kg/m2) were also at higher risk of disability. In men, relationships were weaker since BMI was only associated with mobility restriction, with a higher risk for both underweight and obese subjects.

CONCLUSION

These results are in favor of a strong association between obesity and the three domains of disability and incontinence. Weaker relationships between underweight and disability were observed. Results suggest that maintaining a BMI in the healthy range could contribute to independence in activities of daily living.

Vers une prévention de la démence ?

Many studies have shown that high blood pressure and, to a lesser extent, other vascular risk factors could be the target of interventions aiming to reduce the incidence of dementia. Two large controlled trials have demonstrated that blood pressure lowering drugs have a significant effect on the risk of dementia including Alzheimer's disease. On another hand, large epidemiological studies have shown associations between different vascular factors and dementia. Overall, these data suggest that interventions aiming to reduce the level of vascular risk factors might prevent dementia. The expected benefit of these interventions could be estimated from data provided by epidemiological studies, but large population-based controlled studies are needed to demonstrate the efficacy of preventive interventions.