Sex Differences in Youth with Chronic Tic Disorder and Tourette Syndrome: Evaluation of Tic Severity, Psychological Profiles, and Quality of Life

Background: Tourette syndrome (TS) and Chronic Tic Disorder (CT) are neurodevelopmental conditions involving motor and/or phonic tics. Youth with tics may encounter feelings of isolation, diminished self-esteem and quality of life, and academic difficulties. A growing body of scientific literature suggests sex differences in youth with tics, but findings have been mixed so far. Because symptom severity peaks around puberty, understanding sex differences in tic manifestations and associated symptoms during this critical period is essential. Therefore, we aimed to assess sex differences related to tic symptoms, action planning styles, quality of life, and externalizing/internalizing symptoms in youth with tics. Methods: Our sample consisted of 66 youths with tics (19 girls) aged 7-14 (mean = 10 years). Youths were assessed with clinical interviews, as well as self- and parent-reported inventories evaluating tic symptoms, psychological profiles, and quality of life. Results: While no differences in tic symptoms were found, girls exhibited lower functional inflexibility, reduced overall functional planning effectiveness, and higher impairment in the psychological well-being subscale than boys. Additionally, girls had reduced general life satisfaction and social self-esteem. Boys reported more explosive outbursts, higher levels of hyperactivity, and more difficulties with self-concept. Conclusions: Our analyses suggested differences in several manifestations associated with tics. This introduces new perspectives that refine our understanding of sex differences. A better understanding of sex differences in tic disorders may eventually improve outcomes for all individuals living with these conditions.

Digital platforms to facilitate physical activities for people with physical or sensory disabilities: A scoping review

BACKGROUND

People with disabilities (PWD) commonly experience difficulties in accessing their environments, which can lead to restricted participation in outdoor leisure-time physical activity. Participating in outdoor leisure-time physical activity (OLTPA) provides health and social benefits to PWD and benefits to the communities in which they live.

OBJECTIVE

The aim of the study was to identify features existing in digital platforms that facilitate access to OLTPA for PWD.

METHODS

A scoping review was conducted in four library databases and in Google advance search to identify relevant scientific and grey literature, and websites. Each step of the review was independently conducted by two co-authors who confirmed consensus of results. Descriptive data analyses were performed.

RESULTS

Seven scientific studies and ten websites were included in the scoping review. Seven presented mobile apps, nine presented a website and one presented an online database. Sources reported five main obstacles to using digital platforms that support access to physical activities (e.g., lack of digital literacy, technical issues, unintuitive design), and 10 facilitators (e.g., possibility to personalize your online space, accessibility features of the navigation). Among these sources, a trend emerged in the most important factors and features to consider for the visuals and navigation of the platforms.

CONCLUSION

The features of digital platforms that facilitate access to OLTPA include intuitive design compliant with accessibility guidelines and supported by navigation tools, personalization of the online space, and features for social interactions.

Automatic detection of skate strokes in short-track speed skating using one single IMU: validation of a new method

Greater impulse is a key performance indicator of success in short track speed skating. The main objective of this study was to develop a method to measure skating strokes using a single IMU. Eight elite or world-class speed skaters had one IMU placed against their skin on the lower back, and a camera setup was positioned to capture the test. A maximal speed trial was then executed by each participant, and the data were analysed to estimate agreement between the camera and IMU estimates of skate stroke events. Inter-evaluator reliability was assessed on a dataset of 22 athletes performing speed trials as well. The algorithm detected 100% of the strokes identified on the video capture system with a root mean square error of 0.06s. Bland-Altman analysis showed a bias of 0.03s between the two methods, which corresponds to the frame rate of the camera. The inter-evaluator reliability yielded an intra-class correlation of 1.00 (ICC3,1) from a dataset of 7089 strokes. This study provides an example of on-ice evaluation of speed skating strokes using a single IMU. This equipment is less expensive than that employed by previous authors and can be implemented in training situations with low invasiveness.

Barriers and facilitators of public transport use among people with disabilities: a scoping review

Barriers to public transport use may be experienced differently by people with various types of disabilities (e.g., physical, intellectual, cognitive, sensory). Thus, it is important to identify the variable needs within each element of the travel chain. For example, the unavailability or low volume of auditory announcements in a stop or station or on the public transport vehicle may be a barrier to people with visual disability who rely on hearing the information. Consequently, this could provoke negative emotions and unpleasant experiences, which may not be the case for people with physical disabilities. The primary objective was to describe the barriers and facilitators to using public transport experienced by people with disabilities (PWD). The secondary aim was to explore experiences in terms of self-efficacy and satisfaction, when using public transport among people with disabilities. A scoping review was conducted. The search was performed in MEDLINE, TRANSPORT DATABASE, PsycINFO, EMBASE, and WEB OF SCIENCE from 1995 to 2023. Of 6,820 citations identified, 34 articles were included in the review for extraction. The main physical and social barriers included lack of ramp, long walking distance, long waiting time, unavailability of information at bus stop or station, and drivers' negative attitudes towards PWD. Personal factors that prevented the use of public transport included lack of confidence, and decreased satisfaction with public transport use. Strategies such as providing ramps on public transport vehicles, availability of kneeling buses and courtesy of bus drivers, and travel training were considered as enablers to the use of public transport that can lead the improved self-efficacy and satisfaction. In conclusion, this review identified the physical and social barriers and facilitators in travel chain, and highlighted issues related to lack of confidence or self-efficacy and decreased satisfaction when PWD and older adults are using public transport. Identifying and understanding the barriers and facilitators to the use of public transport by PWD is a milestone that may help policy makers and transport operators around the world to develop and implement interventions enabling access, use and inclusion of this mode of transport, as the experiences of PWD when using this mode of transport have an impact on their well-being.

The persistence of emamectin benzoate in marine sediments with different organic matter regimes, temperature conditions, and antibiotic presence

The objectives of this 318-day study are to determine half-lives of the anti-sea lice medication emamectin benzoate (EMB) under conditions present in sediments at aquaculture sites and document the degradation of EMB into its main metabolite desmethyl emamectin benzoate (DES). Tested conditions include different matrix types (sand, mud), two temperatures (4, 10 degrees), organic matter presence (fish feed waste and feces), and the presence of oxytetracycline. We document a transformation ratio of EMB to DES of 0.16 to 4.4 % and show that the co-presence of oxytetracycline increases EMB calculated half-lives to values >6000 days for mud matrices. EMB incubated in high organic enrichment regimes was not observed to degrade at 4 degrees. Multivariate analyses show interactions between sediment conditions (matrix, temperature, organic matter [OM], oxytetracycline) influence EMB persistence and DES:EMB ratios. Ranges of EMB half-lives and information on metabolites can be used to anticipate potential effects on marine communities.

Toxicity and risk management of oil-spiked sediments by diluted bitumen for two freshwater benthic invertebrates

Diluted bitumen (dilbit) is an unconventional oil produced by the oil sands industry in Canada. Despite the knowledge available on hydrocarbon toxicity, the effects of diluted bitumen on benthic organisms are still largely unknown. Moreover, in Quebec there are only provisional threshold values of 164 mg/kg C₁₀-C₅₀ for chronic effects and 832 mg/kg for acute effects. The protectiveness of these values for benthic invertebrates has not been tested for heavy unconventional oils such as dilbit. Two benthic organisms, the larvae of Chironomus riparius and Hyalella azteca, were exposed to these two concentrations and to an intermediate concentration (416 mg/kg) of two dilbits (DB1 and DB2) and a heavy conventional oil (CO). The aim of the study was to assess the sublethal and lethal effects of spiked sediment by dilbit. The oil was rapidly degraded in the sediment, especially in the presence of C. riparius. Amphipods were much more sensitive to oil than chironomids. LC_50-14d values for H. azteca were 199 mg/kg C₁₀-C₅₀ for DB1, 299 mg/kg for DB2 and 8.42 mg/kg for CO compared to LC_50-7d values for C. riparius of 492 mg/kg for DB1, 563 mg/kg for DB2 and 514 mg/kg for CO. The size of the organisms was reduced compared to controls for both species. The defense enzymes (GST, GPx, SOD and CAT) were not good biomarkers in these two organisms for this type of contamination. The current provisional sediment quality criteria seem too permissive for heavy oils and should be lowered.

Metabolization of emamectin benzoate into desmethyl emamectin benzoate in spiked marine sediments

Emamectin benzoate (EMB) (4″deoxy- 4″-epi-methylaminoavermectin) is a pesticide developed to control pests on various crops, and in forestry. It is also used in salmon aquaculture to control sea lice infestations as an in-feed therapeutant. Little is known about EMB metabolites and potential associated toxicities in marine sediments. In this study, we used natural marine sediments (sand and mud) fortified at an EMB concentration of 60 ppb (wet weight). Results show an almost immediate transformation of EMB to Desmethyl EMB (DES) with no increased rates of metabolization when stored sediment samples were incubated for up to 16 h. The transformation ratio of EMB to DES represented between 0.16 and 0.39% of EMB; values are lower than what has been observed in fish tissue. Data suggest that DES is generated through both abiotic (tested after autoclaving marine sediments) and biological processes. Further work on freshly sampled marine sediments with EMB deposits, different organic regimes, and a detailed assessment of active bacterial communities are necessary to better evaluate the EMB to DES rate of transformation around aquaculture sites.

Design and structure-activity relationships of novel inhibitors of human rhinovirus 3C protease

Human rhinovirus (HRV) is a primary cause of common cold and is linked to exacerbation of underlying respiratory diseases such as asthma and COPD. HRV 3C protease, which is responsible for cleavage of viral polyprotein in to proteins essential for viral life-cycle, represents an important target. We have designed proline- and azetidine-based analogues of Rupintrivir that target the P2 pocket of the binding site. Potency optimization, aided with X-ray crystallography and quantum mechanical calculations, led to compounds with activity against a broad spectrum of HRV serotypes. Altogether, these compounds represent alternative starting points to identify promising leads in our continual efforts to treat HRV infections.

From distress to illness: a critical analysis of medicalization and its effects in clinical practice

This paper is precisely aimed at exposing the limits of psychiatry's scientific claim-making and exploring how psychiatric diagnoses come to be utilized in practice and affect those who become pathologized. Drawing on research findings in the field of HIV/AIDS nursing, we portray the impact of psychiatric pathologization of women who see their bodies transformed by antiretroviral therapy and subsequently, must accept that their response to these changes become the target of psychiatric labelling and interventions. In this paper, we therefore engage with the reader in a critical analysis that exposes the tensions that exist between individual experiences of distress and psychiatric pathologization. The first section of the paper is dedicated to the presentation of a theoretical framework in which we explore the medicalization process and the ontological issues regarding psychiatric diagnoses. The second section seeks to present the results from a qualitative research study in the field of HIV/AIDS nursing and serves as a case example to foster discussions on the implications of psychiatric pathologization in clinical practice.

The effects of word length, articulation, oral-motor movement, and lexicality on gait: a pilot study

Previous research has suggested that articulatory demands are important predictors of the impact of dual-task interference on spatial-temporal parameters of gait. In this study, we evaluated the effects of word length, oral-motor movement, articulation, and lexicality, within a verbal task, on a continuous gait task. Fifteen healthy young women participated in a study in which two word lengths (monosyllabic and bisyllabic) were crossed with four levels of secondary task complexity (no dual-task, non-speech movement, spoken non-word, and spoken word). Spatial and temporal parameters of gait were measured using a 23' instrumented carpet. Results indicated a significant multivariate main effect for task type, F(15, 120)=3.07, that explained 71.1% of the demonstrated variability in gait. Univariate analyses of this main effect revealed statistically significant effects for velocity, step time, swing time, and stance time, but no statistically significant effect for step length. Post hoc analyses suggested that dual-task interference produced significant changes in the parameters of gait, but that this interference was not significantly greater with non-words as compared to the non-speech movement condition, nor was it significantly greater with words as compared to non-words. The results of this systematic deconstruction of a simple verbal task suggest that the motor component of a secondary speech task may produce the largest amount of interference within a dual-task interference paradigm.

Perception and biomechanics data in a manual handling task: a comparative study

This paper explores the use of subjective perception tasks and its correlations with biomechanical data in the evaluation of manual material handling. Three main dimensions were considered for perception: physical regroups sensations issued from a specific body area; operative regroups feelings related to the execution of the task; and performance regroups feelings that involve a judgement on the execution or reflect overall sensations. The following questions were then explored. To what extent are perception data related to biomechanics data? Do both approaches lead to similar conclusions or interpretations when effect of practice, format and off-centre were tested? How can they complement one another? The task consisted of transferring 50 series of three 15 kg loads in order to verify the impact of free practice, format (box/cylinder) and load centre of gravity position. Eleven subjects rated perception on a CR-10 scale (Borg 1982) after each series. The session was completed with an interview on perception. The net resulting moment was systematically found to be the best correlated with data perception. While all physical and performance items corresponded in various ways to biomechanics data, perceptions associated with operative dimension appeared to be less related with biomechanical data. As regards the impact of practice, format and off-centre, both approaches would lead to the same conclusions, except for the effect of the off-centre. Verbal data add rational information about how or why perception can or cannot be reflected in biomechanics data. How both approaches can be matched more closely in manual handling is discussed.

Ergonomic identification and biomechanical evaluation of workers' strategies and their validation in a training situation: summary of research

Our goal was to evidence the role of workers in the search for safer manual handling strategies. Different strategies used by expert and novice workers, such as footwork (positioning/displacement), box manoeuvres (handgrips and load tilting) and posture were ergonomically identified. They were biomechanically evaluated to shed light on their potential for safe handling by reducing back loadings, back asymmetries and mechanical work requirements. The experts' strategies were validated in a training situation and evaluated by two independent studies among novice workers. The first, a control study, showed that free practice did not lead to safer handling practices. The second, a training situation based on observing contrasted performances of experts and novices for footwork, box manoeuvres and back posture, when combined with practice and the search for optimal solutions, prompted the novices to adopt new ways of manoeuvring boxes and positioning themselves that appear safer for back efforts, asymmetries, and mechanical work. These elements should be included in educational programs for safe handling.

RELEVANCE

The observation of contrasted strategies of expert and novice workers using an ergonomic approach, supplemented by biomechanical evaluations of these strategies, is a key factor in designing training programs for safe handling.

New real-time PCR assay for rapid detection of methicillin-resistant Staphylococcus aureus directly from specimens containing a mixture of staphylococci

Molecular methods for the rapid identification of methicillin-resistant Staphylococcus aureus (MRSA) are generally based on the detection of an S. aureus-specific gene target and the mecA gene. However, such methods cannot be applied for the direct detection of MRSA from nonsterile specimens such as nasal samples without the previous isolation, capture, or enrichment of MRSA because these samples often contain both coagulase-negative staphylococci (CoNS) and S. aureus, either of which can carry mecA. In this study, we describe a real-time multiplex PCR assay which allows the detection of MRSA directly from clinical specimens containing a mixture of staphylococci in <1 h. Five primers specific to the different staphylococcal cassette chromosome mec (SCCmec) right extremity sequences, including three new sequences, were used in combination with a primer and three molecular beacon probes specific to the S. aureus chromosomal orfX gene sequences located to the right of the SCCmec integration site. Of the 1,657 MRSA isolates tested, 1,636 (98.7%) were detected with the PCR assay, whereas 26 of 569 (4.6%) methicillin-susceptible S. aureus (MSSA) strains were misidentified as MRSA. None of the 62 nonstaphylococcal bacterial species or the 212 methicillin-resistant or 74 methicillin-susceptible CoNS strains (MRCoNS and MSCoNS, respectively) were detected by the assay. The amplification of MRSA was not inhibited in the presence of high copy numbers of MSSA, MRCoNS, or MSCoNS. The analytical sensitivity of the PCR assay, as evaluated with MRSA-negative nasal specimens containing a mixture of MSSA, MRCoNS, and MSCoNS spiked with MRSA, was approximately 25 CFU per nasal sample. This real-time PCR assay represents a rapid and powerful method which can be used for the detection of MRSA directly from specimens containing a mixture of staphylococci.

The efficacy of training for three manual handling strategies based on the observation of expert and novice workers

OBJECTIVES

To evaluate the efficacy of training for three manual handling strategies, i.e. load tilting/hands positioning, shoulders positioning and feet orientation based on the observation of the contrasted strategies of expert and novice workers and free practice using a search approach.

DESIGN

Ten novice male workers were tested at pre-training (one trial) and post-training with homogeneous boxes (three trials) and heterogeneous boxes (two trials) sampled from two sessions. Training took place with homogeneous boxes whereas heterogeneous boxes were new situations.

BACKGROUND

The effectiveness of training programs in safe handling and the repetition of specified techniques are contested; they should rather be based on expert workers' strategies.

METHODS

Pre-training and post-training trials were analyzed with five video cameras and a large force plate. The biomechanical variables included three safety criteria: net 3D resulting moments at L5/S1, asymmetry of posture/efforts at L5/S1 and mechanical work on load; kinematics and ergonomic variables were used as explicative variables.

RESULTS

Training produced safer strategies by reducing mechanical work and back extensor moments; this occurred in both load conditions, an indication of the transfer of knowledge. These strategies consisted of changes in load maneuvers (tilting/hand positioning) and feet orientation.

CONCLUSIONS

Training programs should be based on observations of workers.

RELEVANCE

These results may guide the specialists involved in training programs. Training based on a search approach by the learner and anchored on observations of contrasted strategies (load tilts/hands positioning and feet orientation) by experts and novices appears promising for safe handling.

Effects of creatine loading and depletion on rat skeletal muscle contraction

1. In humans, the effects of dietary creatine supplementation are controversial, with some studies showing increased muscle force and fatigue resistance and others reporting no effect on exercise performance. Little is known about the effects of creatine on muscle contractile properties. 2. Rats were fed a standard diet, creatine for 10 days or beta-guanidinopropionate, which depletes muscle creatine, for 7 days. Contractile properties were measured in isolated extensor digitorum longus and sternohyoid muscle as representative limb and upper airway dilator muscles, respectively. 3. Creatine had no effect on specific twitch and tetanic tension, contractile kinetics, twitch/tetanus tension ratio, the tension-frequency relationship or fatigue in both muscles. beta-Guanidinopropionate had no effect on the twitch and tetanic tension, contractile kinetics, twitch/tetanus tension ratio or tension-frequency relationship, but significantly increased (P < 0.05, anova) fatigue in both muscles. 4. Therefore, although creatine depletion increases fatigue, creatine loading has no effects on extensor digitorum longus and sternohyoid muscle contractile properties.

The menstrual cycle and susceptibility to coriolis-induced sickness

Survey studies on motion sickness susceptibility suggest that females tend to report greater severity in illness and higher incidence of vomiting than males. Menstruation is said to be a contributing factor. A recent study suggested that females were least susceptible to seasickness during ovulation in a "round the world" yacht race. Sixteen subjects (18-36 years old) were exposed to Coriolis cross-coupling stimulation in the laboratory. They were tested once during permenstruation (Day 1-5), ovulation (Day 12-15) and premenstruation (Day 24-28), based on a normalized 28-day cycle, in a randomised design. Physiological measurements of motion sickness included forearm and calf cutaneous blood flow. Subjective evaluation of sickness symptoms was based on Graybiel's diagnostic criteria and Golding's rating method. Our results indicated that under controlled laboratory conditions, different phases of the menstrual cycle appear to have no influence on subjective symptoms of motion sickness or on cutaneous blood flow increase in the forearm and calf. The lack of commonality between the types and levels of hormones that are released during motion sickness and those that are involved in different menstrual phases appears to support our findings.

Assessment of a three-dimensional robotic model for biomechanical-data acquisition of human movement

The use of a kinematic robotic model has not been implemented in the biomechanical-data acquisition protocol, as it has in workplace analysis, ergonomics and design. The purpose of this paper was to assess the use of a kinematic model to retrieve frames of human movements from data obtained at a low sampling frequency. From experimental trials with an original sampling frequency of 60 Hz, the data were sampled again at two lower frequencies, 5 Hz and 10 Hz. The model was then used to reconstitute the data to its original frequency (60 Hz). The results demonstrated that it was possible to retrieve a full 3-D human movement from a sampling rate lower than normal without sacrificing accuracy. It was observed from both reduced sampling frequencies that the error level was comparable to the usual accuracy of a DLT 3-D reconstruction technique. It was therefore concluded that the data retrieved from these two frequencies were very similar to the original data sampled at 60 Hz.

Glucose and glucoregulatory modulation of memory scanning, event-related potentials and EEG in elderly subjects

Endogenous P300b event-related potential (ERP) and behavioral performance measures, extracted during a visual memory scanning task, and spectral indices of resting electroencephalographic (EEG) activity, were assessed in 12 healthy elderly adults before and after double-blind oral administration of a placebo or glucose (50 mg) beverage. Glucoregulation was estimated by deriving a recovery index to categorize subjects as having better (BR) or poorer (PR) blood glucose recovery. Although glucoregulatory status did not impact on EEG or task performance, PR subjects exhibited reduced P300b areas relative to BR subjects prior to beverage administration. Glucose did not alter P300b or memory scanning performance but, regardless of glucoregulatory status, it increased the EEG power in the slow alpha frequency band. The study results suggest that peripheral glucoregulation can influence neuroelectric measures of cognition and that the acute ingestion of glucose can modulate central arousal processes.

Development of a standardized, comprehensive "ideal drug detail"

OBJECTIVES

To develop a standardized, comprehensive ideal drug detail for use in face-to-face education about individual drugs.

METHODS

A random sample of 603 physicians and pharmacists was selected and stratified to include input from each of the following specialties: family practice, internal medicine, surgery, pediatrics, psychiatry, obstetrics/gynecology, geriatric medicine and clinical pharmacology. Thirty-one potential items were generated by the investigators from a preliminary survey of a local convenience sample of physicians and pharmacists. A modified Delphi consensus process was used in the large sample to determine which items should be included in the ideal drug detail. In each round of the Delphi process, respondents rated each item on a seven-point scale of importance and were then given feedback of the cumulative ratings for each item. Rounds were continued until consensus was obtained on all items.

RESULTS

The response rate to the first round was 55.3%; 85.5% of these respondents responded to the second round. Response rates varied between specialties from 44% to 70%. Attempts to contact nonresponders to measure potential nonrespondent bias were unsuccessful. Consensus was obtained on 19 items after the first round, and on the remaining 12 items after the second round. Four items were dropped because they were unimportant. There was variation in modal response between specialties on eight items.

CONCLUSIONS

Consensus was obtained among a sizable and interested sample of Canadian physicians and pharmacists on the items of information needed to prescribe a drug appropriately. Subsequent work will refine this list into a usable template to develop ideal drug details for specific drugs, to develop an assessment process to measure quality of information, and to assess the impact of this program on prescribing and patient outcomes.

Glucose regulation and brain aging

Blood glucose regulation is not only a complex phenomenon but glucose regulatory levels also vary significantly across individuals. Thus, whereas individuals compromised with moderately elevated blood glucose levels are diagnosed as having impaired glucose tolerance, excessive blood glucose levels render a Type II diabetes diagnosis. Type II diabetes prevalence rates in the adult population have been estimated to be between 6 and 10 percent. Although Type II diabetes has been typically associated with older people, the disease has become much more common among young adults and children. It has become increasingly evident that protracted glucose tolerance impairment usually precedes a type II diabetes diagnosis, although impaired glucose tolerance will not necessarily progress to a diabetic state. Furthermore, a number of studies have shown that impaired glucose tolerance or type II diabetes is associated with impaired cognitive function in older subjects. In addition, we recently found that cognitive deficits are also associated with moderately impaired glucose regulation in young healthy volunteers. These data, although in need of confirmation and extension, suggest that impaired glucose tolerance is associated with impaired cognition, independent of age. Moreover, since impaired glucose tolerance is more prevalent than diabetes across all ages, then our finding lead to the implication that impaired cognitive function may be more prevalent in the general population than previously estimated. Finally, the dysfunction of glucoregulatory mechanisms may be an important intervening factor when studying the evolution of cognitive function through the aging process.

Estrogen replacement therapy improves baroreflex regulation of vascular sympathetic outflow in postmenopausal women

BACKGROUND

Menopausal estrogen loss has been associated with increased cardiovascular disease in postmenopausal women. However, the link between estrogen and cardiovascular disease remains unclear. Some data suggest estrogen mediates its effect through changes in arterial pressure and its regulation. However, the data available in older women are equivocal regarding estrogen's ability to reduce resting arterial pressure or to improve its regulation.

METHODS AND RESULTS

We studied 11 healthy, postmenopausal women before and after 6 months of estrogen administration. Arterial pressure was measured by brachial auscultation and finger photoplethysmography. Vascular sympathetic nerve activity was measured in the peroneal nerve by microneurography, and the slope of the relations between changes in heart period, sympathetic activity, and arterial pressure caused by bolus infusions of nitroprusside and phenylephrine were used as an index of baroreflex gain. Estrogen therapy did not change systolic pressure (128+/-2 versus 123+/-2 mm Hg) or cardiac-vagal baroreflex gain (6.6+/-0.9 versus 6.7+/-0.7 ms/mm Hg). However, vascular sympathetic baroreflex gain was increased (-4.6+/-0.6 versus -7.4+/-1.0 arbitrary integrated units/mm Hg; P=0.02).

CONCLUSION

These findings suggest long-term estrogen replacement therapy has effects on cardiovascular regulation that may not be reflected in resting arterial pressures.

A force platform for large human displacements

This paper provides details of a force platform assembly suitable for measuring the magnitude, position and direction of ground reaction forces for manual handling tasks involving several footsteps in any horizontal direction. An approach to increase the natural frequency with the use of a vibration absorber is used; this frequency was found to be 41+/-2 Hz. The results show a maximum error of 22 N (2% of the full scale output) when a person performs repetitive movements from a squat position to a full extension and back to the squat position. Static tests show the maximal errors to be, vertically, 1.5% of the full scale output (1818+/-33 N), and horizontally, 4.9% of the full scale output (1177+/-6 N).

Mapping of the RNA recognition site of Escherichia coli ribosomal protein S7

Bacterial ribosomal protein S7 initiates the folding of the 3' major domain of 16S ribosomal RNA by binding to its lower half. The X-ray structure of protein S7 from thermophilic bacteria was recently solved and found to be a modular structure, consisting of an alpha-helical domain with a beta-ribbon extension. To gain further insights into its interaction with rRNA, we cloned the S7 gene from Escherichia coli K12 into a pET expression vector and introduced 4 deletions and 12 amino acid substitutions in the protein sequence. The binding of each mutant to the lower half of the 3' major domain of 16S rRNA was assessed by filtration on nitrocellulose membranes. Deletion of the N-terminal 17 residues or deletion of the B hairpins (residues 72-89) severely decreased S7 affinity for the rRNA. Truncation of the C-terminal portion (residues 138-178), which includes part of the terminal alpha-helix, significantly affected S7 binding, whereas a shorter truncation (residues 148-178) only marginally influenced its binding. Severe effects were also observed with several strategic point mutations located throughout the protein, including Q8A and F17G in the N-terminal region, and K35Q, G54S, K113Q, and M115G in loops connecting the alpha-helices. Our results are consistent with the occurrence of several sites of contact between S7 and the 16S rRNA, in line with its role in the folding of the 3' major domain.

Dynamic regulation of middle cerebral artery blood flow velocity in aging and hypertension

BACKGROUND AND PURPOSE

Although aging and hypertension may predispose hypertensive elderly subjects to cerebral hypoperfusion during orthostatic stress, their effects on the acute cerebral autoregulatory response to hypotension are not known.

METHODS

Continuous middle cerebral artery blood flow velocity (BFV) (transcranial Doppler ultrasound) and mean arterial pressure (MAP, Finapres) were measured in response to (1) acute hypotension during standing, (2) steady-state sitting and standing, and (3) hypercarbia during CO(2) rebreathing in 10 healthy young subjects (age 24+/-1 years), 10 healthy elderly subjects (age 72+/-3 years), and 10 previously treated hypertensive elderly (age 72+/-2 years) subjects. CO(2) reactivity was computed as the slope of cerebrovascular conductance (CVC=BFV/MAP) versus end-expiratory CO(2). Coherence, transfer magnitudes, and phases between low-frequency MAP and BFV signals were computed from their autospectra during 5 minutes of sitting and standing.

RESULTS

MAP fell to a similar extent in all groups by an average of 21 to 26 mm Hg (22% to 26%) within 30 seconds of standing. Mean BFV also fell in all subjects but significantly less in the older subjects (-4.7+/-0. 7 cm/s in hypertensives and -5.3+/-1.2 cm/s in normotensives, P=NS) compared with younger subjects (-10.1+/-1.1 cm/s, P<0.05). CO(2) reactivity was greater in the young subjects (0.19+/-0.01) compared with normotensive (0.14+/-0.01, P<0.05) and hypertensive elderly subjects (0.11+/-0.02, P<0.05) (P=NS between elderly groups). Fewer hypertensive subjects had coherence between MAP and BFV signals; for subjects with coherence, there were no significant group differences in phase or transfer magnitudes in either sitting or standing positions.

CONCLUSIONS

Despite reduced CO(2) reactivity, elderly normotensive and previously treated hypertensive subjects retain cerebral autoregulatory capacity in response to acute orthostatic hypotension.

Strategies of load tilts and shoulders positioning in asymmetrical lifting. A concomitant evaluation of the reference systems of axes

OBJECTIVES

To evaluate two handling factors on asymmetry of posture and efforts and to evaluate different reference systems of axes on the characterization of asymmetry.DESIGN. Ten novice workers performed three tasks evaluated for the effects of load tilting (tilts vs no tilts) and shoulders positioning (non-parallel vs parallel to the ground). Specific comparisons were made using three referential systems.BACKGROUND. Box handgrips/tilting and body posture are factors differentiating expert and novice workers which present a potential for reducing asymmetries. The literature also suggests that different conclusions may be reached about asymmetry with different systems of axes.METHODS. Net 3D moments at L5/S1 were obtained from two force platforms, four video cameras and inverse dynamic analyses using three reference systems of axes (trunk, pelvis, and joint).RESULTS. Tilting the load presented clear advantages of reducing the duration and trajectory of efforts, better positioning the load and reducing knee flexion, peak trunk extensors and mechanical work on the load. The maintenance of the shoulders parallel reduced asymmetries of posture and efforts but the results were affected by the type of reference system of axes chosen.CONCLUSIONS. Box tilting and shoulders positioning should be considered in the reduction of risk factors. More research is needed to define referential systems and characterize asymmetry. RelevanceBox tilting and shoulders positioning appear to be two fundamental elements to take into account in the formation programs based on prevention of risk factors. The importance of asymmetry among the risk factors emphasizes the need for better characterization of this risk.

Evolution of anthropoid jaw loading and kinematic patterns

Major transformations in the skull and masticatory system characterized the evolution of crown anthropoids. To offer further insight into the phylogenetic and arguably adaptive significance of specific primate mandibular loading and kinematic patterns, allometric analyses of metric parameters linked to masticatory function are performed within and between 47 strepsirhine and 45 recent anthropoid species. When possible, basal anthropoids are considered. These results are subsequently integrated with prior experimental and morphological work on primate skull form. As compared to strepsirhines, crown anthropoids have a vertically longer ascending ramus linked to a glenoid and condyle positioned relatively higher above the occlusal plane. Interestingly, anthropoids and strepsirhines do not exhibit different mean ratios of condylar to glenoid height, which suggests that both clades are similar in their ability to evenly distribute occlusal contacts and perhaps forces along the postcanine teeth. Thus, given the considerable suborder differences in the scaling of both glenoid and condylar height, we argue that much of this variation in jaw-joint height is linked to suborder differences in relative facial height due in turn to increased encephalization, basicranial flexion, and facial kyphosis in anthropoids. Due to a more elongate ascending ramus, anthropoids evince more vertically oriented masseters than like-sized strepsirhines. Having a relatively longer ramus and a more medially displaced lateral pterygoid plate, crown anthropoids exhibit medial pterygoids oriented similar to those of strepsirhines, but with a variably longer lever arm. As anthropoid masseters are less advantageously placed to effect transverse movements/forces, we argue that balancing-side deep-masseter activity underlying a wishboning loading regime serves to increase, or at least maintain, transverse levels of jaw movement and occlusal force at the end of the masticatory power stroke. Crown anthropoids are also more isognathic and isodontic than strepsirhines. A consideration of early anthropoids suggests that the crown anthropoid masticatory pattern, i.e., more vertical masseters due to a high condyle as well as greater isognathy and isodonty, occurred stepwise during stem anthropoid evolution. This appears to correspond to a more transverse, and perhaps progressively larger, power stroke across oligopithecids, parapithecids, and propliopithecids.

Rapid detection of group B streptococci in pregnant women at delivery

BACKGROUND

Group B streptococcal infections are an important cause of neonatal morbidity and mortality. A rapid method for the detection of this organism in pregnant women at the time of delivery is needed to allow early treatment of neonates.

METHODS

We studied the efficacy of two polymerase-chain-reaction (PCR) assays for routine screening of pregnant women for group B streptococci at the time of delivery. We obtained anal, vaginal, and combined vaginal and anal specimens from 112 pregnant women; in 57 women, specimens were obtained before and after the rupture of the amniotic membranes. The specimens were tested for group B streptococci by culture in a standard selective broth medium, with a conventional PCR assay, and with a new fluorogenic PCR assay.

RESULTS

Among the 112 women, the results of the culture of the combined vaginal and anal specimens were positive for group B streptococci in 33 women (29.5 percent). The two PCR assays detected group B streptococcal colonization in specimens from 32 of these 33 women: the one negative PCR result was in a sample obtained after the rupture of membranes. As compared with the culture results, the sensitivity of both PCR assays was 97.0 percent and the negative predictive value was 98.8 percent. Both the specificity and the positive predictive value of the two PCR assays were 100 percent. The length of time required to obtain results was 30 to 45 minutes for the new PCR assay, 100 minutes for the conventional PCR assay, and at least 36 hours for culture.

CONCLUSIONS

Colonization with group B streptococci can be identified rapidly and reliably by a PCR assay in pregnant women in labor both before and after the rupture of membranes.

Early human occupation of the Red Sea coast of Eritrea during the last interglacial

The geographical origin of modern humans is the subject of ongoing scientific debate. The 'multiregional evolution' hypothesis argues that modern humans evolved semi-independently in Europe, Asia and Africa between 100,000 and 40,000 years ago, whereas the 'out of Africa' hypothesis contends that modern humans evolved in Africa between 200 and 100 kyr ago, migrating to Eurasia at some later time. Direct palaeontological, archaeological and biological evidence is necessary to resolve this debate. Here we report the discovery of early Middle Stone Age artefacts in an emerged reef terrace on the Red Sea coast of Eritrea, which we date to the last interglacial (about 125 kyr ago) using U-Th mass spectrometry techniques on fossil corals. The geological setting of these artefacts shows that early humans occupied coastal areas and exploited near-shore marine food resources in East Africa by this time. Together with similar, tentatively dated discoveries from South Africa this is the earliest well-dated evidence for human adaptation to a coastal marine environment, heralding an expansion in the range and complexity of human behaviour from one end of Africa to the other. This new, wide-spread adaptive strategy may, in part, signal the onset of modern human behaviour, which supports an African origin for modern humans by 125 kyr ago.

CytoView. A prototype computer image-based Papanicolaou smear proficiency test

OBJECTIVE

To develop and assess CytoView, a prototype computer image-based cytology proficiency testing (PT) system, as an alternative to glass-slide cervical cytology PT.

STUDY DESIGN

The computer-based PT consists of 10 cases taken from 10 Pap smears, each of which had received a consensus Clinical Laboratory Improvement Amendments-category diagnosis from three pathologists. Each CytoView "case" was the digital representation of > 8,000 microscopic fields, captured from a selected 5 x 10-mm rectangle of a Pap smear. The 5 x 10-mm capture rectangle was selected from the slide's most representative area for its diagnostic category. The CytoView project team developed each case through a multistep process that included image capture, image alignment, correlation of 10x and 40x images, and image display. The 10-slide CytoView PT prototype was then assessed by groups of cytopathologists and cytotechnologists.

RESULTS

The CytoView prototype PT system was developed and assessed.

CONCLUSION

Preliminary evaluation of CytoView indicated potential for this format as a valid and logistically feasible alternative to the traditional glass slide PT format.

Effect of glucose, glucose regulation, and word imagery value on human memory

Changes in memory performance were examined after intake of a glucose (50 g) or saccharin (50 mg) solution in fasted men and women. Glucoregulation was estimated by using a recovery index to categorize participants within each gender as having poor or good recovery. Memory was assessed with word-learning tasks in which the imagery-evoking value of the words was systematically manipulated to yield high- and low-imagery lists. The results showed that men and women characterized as having poor glucose regulation had significantly worse memory performance under the saccharin condition. This decrement was reversed by glucose ingestion. These effects were observed for both low- and high-imagery words. This study supports the hypothesis that poor glucoregulation is associated with poor memory performance even in young healthy participants and that the ingestion of glucose can improve their memory.

Economic evaluation of donepezil for the treatment of Alzheimer's disease in Canada

BACKGROUND

Donepezil is a new drug recently approved in the United States and Canada for the treatment of Alzheimer's disease (AD). We estimated the cost-effectiveness of donepezil 5 mg daily as an adjunct to usual care in the management of persons with mild-to-moderate AD defined as a Mini-Mental Health State Examination (MMSE) score in the range 10 to 26.

METHODS

Treatment effect data as MMSE change-over-baseline scores were obtained from a 30-week placebo-controlled trial of donepezil. MMSE scores beyond observed trial data were estimated using a Markov model with 10 cycles of 24 weeks based on the placebo MMSE progression observed in the trial. Data from AD subjects in the Canadian Study of Health and Aging were used to estimate costs of nursing home care, community services, medications, and caregiver time as a function of MMSE score. A clinic-based cohort study from Alberta was used to estimate the distribution of AD patients by MMSE score presenting for treatment. The effectiveness measure for the economic model was expected time (over 5 years) spent with nonsevere AD (MMSE > or = 10).

RESULTS

Over 5 years of treatment, donepezil is predicted to reduce health care costs by CA$929 per patient but increase caregiver time costs by CA$48 per patient for an overall cost saving to society of CA$882 per patient. Patients not receiving donepezil are predicted to spend 2.21 years of the 5 years in nonsevere AD compared with 2.41 years for treated patients (a gain of just over 2 months). Sensitivity analysis reveals that cost savings per patient increase if more AD patients are assumed to survive to 5 years; however, if donepezil treatment continues when patients' MMSE score falls below 10, the incremental cost is higher for treatment at CA$1554 per patient.

CONCLUSION

Based on the limited available data, our model predicts that the use of donepezil for mild-to-moderate AD in Canada is associated with lower 5-year costs and less time spent with severe AD when compared with the alternative of usual care with no donepezil therapy. As more reliable long-term data become available, these predictions should be confirmed and/or updated.

Effects of age and gender on autonomic control of blood pressure dynamics

Both age and gender influence cardiovascular autonomic control, which in turn may influence the ability to withstand adverse cardiac events and respond to orthostatic stress. The purpose of this study was (1) to quantify age- and gender- related alterations in autonomic control of blood pressure (BP) and (2) to examine the impact of these autonomic alterations on BP response to orthostatic stress. We measured continuous BP and R-R intervals and vasoactive peptide levels in the supine and 60 degrees head-up tilt positions during paced respiration (0.25 Hz) in 89 carefully screened healthy subjects (41 men, 48 women, aged 20 to 83 years). Data were analyzed by gender (age adjusted) and by age group (gender adjusted). During tilt, women had greater decreases in systolic BP than men (-10.2+/-2 versus -1.2+/-3 mm Hg; P=0.02) and smaller increases in low-frequency (sympathetically mediated) BP power (P=0.02). Upright plasma norepinephrine was lower in women (P=0.02). Women had greater supine high-frequency R-R interval power than men (P=0.0001). In elderly subjects, the tilt-induced increase in low-frequency BP power was also diminished (P=0.01), despite higher supine (P=0.02) and similar upright norepinephrine levels compared with younger subjects. Thus, healthy women have less sympathetic influence on BP and greater parasympathetic influence on R-R interval than men. Elderly subjects also have reduced sympathetic influence on BP, but this appears to be more consistent with a reduction in vasomotor sympathetic responsiveness.

Functional and physical association of a cell surface phospholipid and interleukin-2 receptor p55(alpha) subunits

A phosphatidylcholine-like phospholipid expressed in the outer leaflet of the cell membrane shortly after mitogenic activation of T-cells is described, based on the binding of monoclonal antibody 90. 60.3. Expression of the 90.60.3 phospholipid antigen in T-cells is activation-dependent. Once expressed, the 90.60.3 phospholipid is in direct physical association with the interleukin-2 (IL-2) binding domain of IL-2 receptor alpha subunits, but does not affect IL-2 binding. The association is specific, because the 90.60.3 phospholipid is not found in association with other domains of IL-2 receptor alpha subunits, or near IL-2 receptor beta or gamma subunits. Culturing cytokine-dependent cell lines in the presence of monoclonal antibody 90.60.3 potentiates IL-2-dependent cell survival and proliferation in a dose-dependent manner. In contrast, IL-4-dependent responses are not potentiated. Taken together, the data suggest that specific plasma membrane phospholipids expressed in the outer leaflet after T-cell activation associate with the IL-2 binding domain of IL-2 receptor alpha subunits (and perhaps other cytokine receptors), and may play a role in regulating receptor mobility or signal transduction.

Relation between severity of Alzheimer's disease and costs of caring

BACKGROUND

Data from the Canadian Study of Health and Aging (CSHA) were used to examine the relation between severity of Alzheimer's disease, as measured by the Mini-Mental State Examination (MMSE), and costs of caring.

METHODS

The CSHA was a community-based survey of the prevalence of dementia, including subtypes such as Alzheimer's disease, among elderly Canadians. Survey subjects with a diagnosis of possible or probable Alzheimer's disease were grouped into disease severity levels of mild (MMSE score 21-26), mild to moderate (MMSE score 15-20), moderate (MMSE score 10-14) and severe (MMSE score below 10). Components of care available from the CSHA were use of nursing home care, use of medications, use of community support services by caregivers and unpaid caregiver time. Costs were calculated from a societal perspective and are expressed in 1996 Canadian dollars.

RESULTS

The annual societal cost of care per patient increased significantly with severity of Alzheimer's disease. The cost per patient was estimated to be $9451 for mild disease, $16,054 for mild to moderate disease, $25,724 for moderate disease and $36,794 for severe disease. Institutionalization was the largest component of cost, accounting for as much as 84% of the cost for people with severe disease. For subjects living in the community, unpaid caregiver time and use of community services were the greatest components of cost and increased with disease severity.

INTERPRETATION

The societal cost of care of Alzheimer's disease increases drastically with increasing disease severity. Institutionalization is responsible for the largest cost component.