Concussion can increase the risk of visually induced motion sickness

Concussion can lead to various symptoms such as balance problems, memory impairments, dizziness, and/or headaches. It has been previously suggested that during self-motion relevant tasks, individuals with concussion may rely heavily on visual information to compensate for potentially less reliable vestibular inputs and/or problems with multisensory integration. As such, concussed individuals may also be more sensitive to other visually-driven sensations such as visually induced motion sickness (VIMS). To investigate whether concussed individuals are at elevated risk of experiencing VIMS, we exposed participants with concussion (n = 16) and healthy controls (n = 15) to a virtual scene depicting visual self-motion down a grocery store aisle at different speeds. Participants with concussion were further separated into symptomatic and asymptomatic groups. VIMS was measured with the SSQ before and after stimulus exposure, and visual dependence, self-reported dizziness, and somatization were recorded at baseline. Results showed that concussed participants who were symptomatic demonstrated significantly higher SSQ scores after stimulus presentation compared to healthy controls and those who were asymptomatic. Visual dependence was positively correlated with the level of VIMS in healthy controls and participants with concussion. Our results suggest that the presence of concussion symptoms at time of testing significantly increased the risk and severity of VIMS. This finding is of relevance with regards to the use of visual display devices such as Virtual Reality applications in the assessment and rehabilitation of individuals with concussion.

Evaluating the impact of a national geriatric mental health ECHO educational program on healthcare providers' practice

Project Extension for Community Healthcare Outcomes (ECHO) enables healthcare providers to share knowledge and best practices via telementoring. The ECHO model builds provider capacity and improves care for patients with a variety of health conditions. This study describes a Canada-wide National ECHO pilot project in the area of geriatric mental health and reports on the program's impact on providers' care practices. A mixed-methods approach was used to analyze surveys completed by participating healthcare providers. Program evaluation measured satisfaction, achievement of learning objectives, awareness of issues related to geriatric mental health, and comfort and self-efficacy working with older adults. The program led to a statistically significant increase in participants' awareness of issues related to support for older adults with mental illness and comfort and self-efficacy in managing these patients in their own practice. The National ECHO pilot project was successful in building healthcare providers' capacity to care for older adults with mental health issues and positively impacting their practice. These findings support using the ECHO model to provide ongoing geriatric mental health education for clinicians from across Canada and beyond.

Virtual reality hope machines in a curative imaginary: recommendations for neurorehabilitation research from a critical disability studies perspective

PURPOSE

This paper provides recommendations for neurorehabilitative research informed by insights from critical disability studies (CDS) and a research study that tested an augmented neurorehabilitative technology prototype.

METHODS

The methodology combines critical reflection, feminist science studies and CDS to analyze how neurorehabilitation and disability studies conceptualize notions of disability and cure. It offers recommendations for reconciling the conflicting ideologies of cure that operate within neurorehabilitative research.

RESULTS

The prototype acted as a kind of virtual reality hope machine that tapped into different emotions and language games regarding disability and cure. The result is five recommendations about the ways that a CDS perspective might inform neurorehabilitation research: (I) ensure clarity in recruitment materials to account for dominant social views on disability and the possibility of cure; (II) build "strong objectivity" into research methods through attention to social context and multiple meanings of terms; (III) engage in critical reflection about research processes and findings; (IV) incorporate principles of crip technoscience; and (V) include CDS perspectives in neurorehabilitation education.

CONCLUSIONS

Bridging a conversation between neurorehabilitative research and CDS can address the discrepancies between ideologies of cure, and situate rehabilitation within the wider concerns of social determinants of health and disability justice.Implications for rehabilitationBridging connections between rehabilitation studies and critical disability studies can generate productive insights that open up conversations with disabled people and a commitment to disability justice.Disability and cure are social constructs and may have different meanings for patients and rehabilitation professionals.Clinicians should be mindful of the conflicting ideological constructs and socio-political dimensions of disability and cure that are operating below the surface in the rehabilitation profession and in interactions between clinicians and patients.As technology continues to transform clinical rehabilitation care through virtual reality and other innovative paradigms, rehabilitation clinicians should recognize the potential for these technologies to become "hope machines," generating patient expectations that are idealized constructions of hoped-for outcomes of returning to a previous state or level of functionality rather than predictive expectations of likely results.

Sabotage Detection Using DL Models on EEG Data From a Cognitive-Motor Integration Task

Objective clinical tools, including cognitive-motor integration (CMI) tasks, have the potential to improve concussion rehabilitation by helping to determine whether or not a concussion has occurred. In order to be useful, however, an individual must put forth their best effort. In this study, we have proposed a novel method to detect the difference in cortical activity between best effort (no-sabotage) and willful under-performance (sabotage) using a deep learning (DL) approach on the electroencephalogram (EEG) signals. The EEG signals from a wearable four-channel headband were acquired during a CMI task. Each participant completed sabotage and no-sabotage conditions in random order. A multi-channel convolutional neural network with long short term memory (CNN-LSTM) model with self-attention has been used to perform the time-series classification into sabotage and no-sabotage, by transforming the time-series into two-dimensional (2D) image-based scalogram representations. This approach allows the inspection of frequency-based, and temporal features of EEG, and the use of a multi-channel model facilitates in capturing correlation and causality between different EEG channels. By treating the 2D scalogram as an image, we show that the trained CNN-LSTM classifier based on automated visual analysis can achieve high levels of discrimination and an overall accuracy of 98.71% in case of intra-subject classification, as well as low false-positive rates. The average intra-subject accuracy obtained was 92.8%, and the average inter-subject accuracy was 86.15%. These results indicate that our proposed model performed well on the data of all subjects. We also compare the scalogram-based results with the results that we obtained by using raw time-series, showing that scalogram-based gave better performance. Our method can be applied in clinical applications such as baseline testing, assessing the current state of injury and recovery tracking and industrial applications like monitoring performance deterioration in workplaces.

Toxicity of Herbicide Mixtures to Tropical Freshwater Microalgae Using a Multispecies Test

Agriculture within the Great Barrier Reef catchment area has contributed to pesticide contamination of adjacent freshwater ecosystems that flow into the Great Barrier Reef World Heritage Area. A novel multispecies toxicity test was used to assess the toxicity of diuron and hexazinone, 2 herbicides commonly detected within the Great Barrier Reef catchment area, to a community of 3 tropical freshwater microalgae: Monoraphidium arcuatum, Nannochloropsis-like sp., and Pediastrum duplex. Diuron was the most toxic herbicide, with 10% inhibition concentration (IC10) values of 4.3, 7.1, and 29 µg/L for P. duplex, M. arcuatum, and Nannochloropsis-like sp., respectively, followed by hexazinone, with IC10 values of 15, 18, and 450 µg/L, respectively Toxicity testing on 2 commercial formulations (Barrage, 13.2% hexazinone and 48.6% diuron; Diurex, 90% diuron) showed that additives in the commercial formulations did not significantly increase the toxicity of diuron. Direct toxicity assessments were carried out on water samples from the herbicide-contaminated Sandy Creek, which discharges to the Great Barrier Reef lagoon, and a clean reference site, Tully Gorge in the Tully River. Toxicity was observed in several Sandy Creek samples. Artificial herbicide mixtures were assessed in synthetic soft water and natural freshwaters, with toxic responses being observed at environmentally relevant concentrations. The present study successfully applied a novel multispecies tropical microalgal toxicity test, indicating that it is an effective tool for the assessment of herbicide toxicity in both natural and synthetic freshwaters. Environ Toxicol Chem 2021;40:473-486. © 2020 SETAC.

The Effects of Mild Traumatic Brain Injury on Cognitive-Motor Integration for Skilled Performance

Adults exposed to blast and blunt impact often experience mild traumatic brain injury, affecting neural functions related to sensory, cognitive, and motor function. In this perspective article, we will review the effects of impact and blast exposure on functional performance that requires the integration of these sensory, cognitive, and motor control systems. We describe cognitive-motor integration and how it relates to successfully navigating skilled activities crucial for work, duty, sport, and even daily life. We review our research on the behavioral effects of traumatic impact and blast exposure on cognitive-motor integration in both younger and older adults, and the neural networks that are involved in these types of skills. Overall, we have observed impairments in rule-based skilled performance as a function of both physical impact and blast exposure. The extent of these impairments depended on the age at injury and the sex of the individual. It appears, however, that cognitive-motor integration deficits can be mitigated by the level of skill expertise of the affected individual, suggesting that such experience imparts resiliency in the brain networks that underly the control of complex visuomotor performance. Finally, we discuss the next steps needed to comprehensively understand the impact of trauma and blast exposure on functional movement control.

A History of Concussion Affects Relevancy-Based Modulation of Cortical Responses to Tactile Stimuli

Modulating cortical excitability based on a stimulus’ relevance to the task at hand is a component of sensory gating, and serves to protect higher cortical centers from being overwhelmed with irrelevant information (McIlroy et al., 2003; Kumar et al., 2005; Wasaka et al., 2005). This study examined relevancy-based modulation of cortical excitability, and corresponding behavioral responses, in the face of distracting stimuli in participants with and without a history of concussion (mean age 22 ± 3 SD years; most recent concussion 39.1 ± 30 SD months). Participants were required to make a scaled motor response to the amplitudes of visual and tactile stimuli presented individually or concurrently. Task relevance was manipulated, and stimuli were occasionally presented with irrelevant distractors. Electroencephalography (EEG) and task accuracy data were collected from participants with and without a history of concussion. The somatosensory-evoked N70 event-related potential (ERP) was significantly modulated by task relevance in the control group but not in those with a history of concussion, and there was a significantly greater cost to task accuracy in the concussion history group when relevant stimuli were presented with an irrelevant distractor. This study demonstrated that relevancy-based modulation of electrophysiological responses and behavioral correlates of sensory gating differ in people with and without a history of concussion, even after patients were symptom-free and considered recovered from their injuries.

Development and application of a multispecies toxicity test with tropical freshwater microalgae

Microalgae are commonly used in ecotoxicity testing due to their ease of culturing and rapid cell division rates. These tests generally utilise a single species of algae; however, microalgae occur in the environment as complex communities of multiple species. To date, routine multispecies toxicity tests using tropical microalgae have not been available. This study investigated four tropical freshwater microalgal species for use in a chronic multispecies toxicity test based on the population growth (cell division) rate: Pediastrum duplex, Monoraphidium arcuatum, Nannochloropsis-like sp. and Chlorella sp. 12. Flow cytometric analysis identified the different fluorescence and light scattering properties of each algal species and quantified each species within multispecies mixtures. Following optimisation of test media nutrients and pH, a toxicity testing protocol was developed with P. duplex, M. arcuatum and Nannochloropsis-like sp. There were no significant differences in growth rates of each alga when tested over 72 h as single species or in multispecies mixtures. Atrazine and imazapic, two herbicides with different modes of action, were used to assess the sensitivity of the multispecies toxicity test. Atrazine was toxic to all species with 72-h IC10 values of 7.2, 63 and 280 μg/L for P. duplex, M. arcuatum and Nannochloropsis-like sp. respectively, while imazapic was not toxic to any species at concentrations up to 1100 μg/L. The toxicity of atrazine and imazapic to each microalgal species in the multispecies toxicity test was the same as that determined from single-species toxicity tests indicating that the presence of these microalgae in a mixture did not affect the toxicity of these two herbicides. This study is the first to develop a multispecies tropical microalgal toxicity test for application in freshwaters. This time- and cost-effective tool can be utilised to generate data to assist environmental decision making and to undertake risk assessments of contaminants in tropical freshwater environments.

Simultaneity and Temporal Order Judgments Are Coded Differently and Change With Age: An Event-Related Potential Study

Multisensory integration is required for a number of daily living tasks where the inability to accurately identify simultaneity and temporality of multisensory events results in errors in judgment leading to poor decision-making and dangerous behavior. Previously, our lab discovered that older adults exhibited impaired timing of audiovisual events, particularly when making temporal order judgments (TOJs). Simultaneity judgments (SJs), however, were preserved across the lifespan. Here, we investigate the difference between the TOJ and SJ tasks in younger and older adults to assess neural processing differences between these two tasks and across the lifespan. Event-related potentials (ERPs) were studied to determine between-task and between-age differences. Results revealed task specific differences in perceiving simultaneity and temporal order, suggesting that each task may be subserved via different neural mechanisms. Here, auditory N1 and visual P1 ERP amplitudes confirmed that unisensory processing of audiovisual stimuli did not differ between the two tasks within both younger and older groups, indicating that performance differences between tasks arise either from multisensory integration or higher-level decision-making. Compared to younger adults, older adults showed a sustained higher auditory N1 ERP amplitude response across SOAs, suggestive of broader response properties from an extended temporal binding window. Our work provides compelling evidence that different neural mechanisms subserve the SJ and TOJ tasks and that simultaneity and temporal order perception are coded differently and change with age.

Dietary ingestion of fine sediments and microalgae represent the dominant route of exposure and metal accumulation for Sydney rock oyster (Saccostrea glomerata): A biokinetic model for zinc

Past studies disagree on the extent to which dissolved or dietary uptake contribute to metal bioaccumulation in the filter-feeding Sydney rock oyster (Saccostrea glomerata) in urbanized estuaries. Although most data support the assumption that fine sediments are a major route of metal uptake in these bivalves, some studies based in the Sydney estuary, Australia, have indicated a poor correlation. In the present study, seawater, sediment and microalgae were radiolabelled with (65)Zn tracer and exposed to S. glomerata to assess the influence of dissolved and dietary sources to Zn bioaccumulation. Oysters in the dissolved-phase uptake experiment (5, 25 and 50 μg L(-1) (65)Zn for 4 d followed by 21 days of depuration) readily accumulated (65)Zn for all three concentrations with an uptake rate constant of 0.160±0.006 L dry weight g(-1) d(-1). Oysters in the dietary assimilation experiment (1h pulse-feed of either (65)Zn-radiolabelled suspended fine-fraction (<63 μm) sediment or the microalgae Tetraselmis sp.) accumulated (65)Zn, with assimilation efficiencies of 59 and 67% for fine sediment and microalgae, respectively. The efflux rates were low for the three experiments (0.1-0.5% d(-1)). A bioaccumulation kinetic model predicts that uptake of Zn will occur predominantly through the dietary ingestion of contaminated fine sediment particles and microalgae within the water column, with considerably greater metal bioaccumulation predicted if oysters ingested microalgae preferentially to sediments. However, the model predicts that for dissolved Zn concentrations greater than 40 μg L(-1), as observed during precipitation events, the uptake of the dissolved phase may contribute ≥50% to accumulation. Overall, the results of the present study suggest that all three sources may be important exposure routes to S. glomerata under different environmental conditions, but contributions from dietary exposure will often dominate.

Early modality-specific somatosensory cortical regions are modulated by attended visual stimuli: interaction of vision, touch and behavioral intent

Bimodal interactions between relevant visual and tactile inputs can facilitate attentional modulation at early stages in somatosensory cortices to achieve goal-oriented behaviors. However, the specific contribution of each sensory system during attentional processing and, importantly, how these interact with the required behavioral motor goals remains unclear. Here we used electroencephalography and event-related potentials (ERPs) to test the hypothesis that activity from modality-specific somatosensory cortical regions would be enhanced with task-relevant bimodal (visual-tactile) stimuli and that the degree of modulation would depend on the difficulty of the associated sensory-motor task demands. Tactile stimuli were discrete vibrations to the index finger and visual stimuli were horizontal bars on a computer screen, both with random amplitudes. Streams of unimodal (tactile) and crossmodal (visual and tactile) stimuli were randomly presented and participants were instructed to attend to one type of stimulus (unimodal or crossmodal) and responses involved either an indication of the presence of an attended stimulus (detect), or the integration and summation of two stimulus amplitudes using a pressure-sensitive ball (grade). Force-amplitude associations were learned in a training session, and no feedback was provided during the task. ERPs were time-locked to tactile stimuli and extracted for early modality-specific components (P50, P100, N140). The P50 was enhanced with bimodal (visual-tactile) stimuli that were attended to. This was maximal when the motor requirements involved integration of the two stimuli in the grade task and when the visual stimulus occurred before (100 ms) the tactile stimulus. These results suggest that visual information relevant for movement modulates somatosensory processing as early as the primary somatosensory cortex (S1) and that the motor behavioral context influences this likely through interaction of top-down attentional and motor preparatory systems with more bottom-up crossmodal influences.

Acute toxicity testing with the tropical marine copepod Acartia sinjiensis: optimisation and application

Globally there is limited toxicity data for tropical marine species, and there has been a call for further research and development in the area of tropical marine ecotoxicology. An increase in developmental pressures in northern tropical Australia is causing a higher demand for toxicity test protocols with ecologically relevant species. Copepods are a diverse group of zooplankton that are major components of marine food webs. The calanoid copepod Acartia sinjiensis is widely distributed across tropical and sub-tropical brackish to marine waters of Australia and was identified in a recent comprehensive review of marine tropical toxicity testing in Australia as a suitable test organism. Through a number of optimisation steps including feeding trials, changes to culture and test conditions; a 48-h acute toxicity test with A. sinjiensis was modified to become a highly reliable and reproducible standard test protocol. Control mobility was improved significantly, and the sensitivity of A. sinjiensis to copper (EC50 of 33µg/L), ammonia (EC50 of 10mg/L) and phenol (EC50 of 13mg/L) fell within the ranges of those reported previously, indicating that the modifications did not alter its sensitivity. In a comprehensive literature search we found that this species was the most sensitive to copper out of a range of marine copepods. The test was also successfully applied in toxicity assessments of four environmental samples: two produced formations waters (PFWs) and two mine tailing liquors (MTLs). The toxicity assessments utilised toxicity data from a suite of marine organisms (bacteria, microalgae, copepods, sea urchins, oysters, prawns, and fish). For the PFWs, which were predominantly contaminated with organic chemicals, A. sinjiensis was the most sensitive species (EC50 value 2-17 times lower than for any other test species). For the predominantly metal-contaminated mine tailing liquors, its sensitivity was similar to that of other test species used. The modified 48-h acute toxicity test with A. sinjiensis proved to be a valuable tool in these toxicity assessments, and is recommended for use in tropical marine toxicity assessments for northern Australia.

Feeding difficulties in children with cerebral palsy: low-cost caregiver training in Dhaka, Bangladesh

BACKGROUND

The majority of children with cerebral palsy have feeding difficulties, which, if not managed, result in stressful mealtimes, chronic malnutrition, respiratory disease, reduced quality of life for caregiver and child, and early death. In well-resourced countries, high- and low-cost medical interventions, ranging from gastrostomy tube feeding to caregiver training, are available. In resource-poor countries such as Bangladesh, the former is not viable and the latter is both scarce and its effectiveness not properly evaluated. The aim of this study was to evaluate the effectiveness of a low-cost, low-technology intervention to improve the feeding practices of carers of children with moderate-severe cerebral palsy and feeding difficulties in Bangladesh.

METHODS

An opportunistic sample of 37 caregivers and their children aged 1-11 years were invited to a six-session training programme following an initial feeding assessment with brief advice. During home visits, pre- and post-measures of nutritional status, chest health and feeding-related stress were taken and feeding practices were observed. A control phase was evaluated for 20 of the participant pairs following initial assessment with advice, while awaiting full training.

RESULTS

A minimum of four training sessions showed significant improvements in the children's respiratory health (P = 0.005), cooperation during mealtimes (P = 0.003) and overall mood (P < 0.001). Improvements in growth were inconsistent. Dramatic reductions were observed in caregiver stress (P < 0.001). A significant difference in the outcomes following advice only compared with advice plus training was also observed.

CONCLUSIONS

In situations of poverty, compliance is restricted by lack of education, finances and time. Nonetheless, carers with minimal formal education, living in conditions of extreme poverty were able to change feeding practices after a short, low-cost training intervention, with highly positive consequences. The availability of affordable food supplementation for this population, however, requires urgent attention.

Effects of alumina refinery wastewater and signature metal constituents at the upper thermal tolerance of: 1. The tropical diatom Nitzschia closterium

Ecotoxicological studies, using the tropical marine diatom, Nitzschia closterium (72-h growth rate), were undertaken to assess potential issues relating to the discharge from an alumina refinery in northern Australia. The studies assessed: (i) the species' upper thermal tolerance; (ii) the effects of three signature metals, aluminium (Al), vanadium (V) and gallium (Ga) (at 32°C); and (iii) the effects of wastewater (at 27 and 32°C). The critical thermal maximum and median inhibition temperature for N. closterium were 32.7°C and 33.1°C, respectively. Single metal toxicity tests found that N. closterium was more sensitive to Al compared to Ga and V, with IC(50)s (95% confidence limits) of 190 (140-280), 19,640 (11,600-25,200) and 42,000 (32,770-56,000) μg L(-1), respectively. The undiluted wastewater samples were of low toxicity to N. closterium (IC(50)s>100% wastewater). Environmental chemistry data suggested that the key metals and discharge are a very low risk to this species.

The development of marine Toxicity Identification Evaluation (TIE) procedures using the unicellular alga Nitzschia closterium

Unicellular algae are highly sensitive to a wide range of toxicants and have been used extensively in ecotoxicological testing. This, along with their ability to grow in very small test volumes over short test durations, make them ideal test organisms for use in Toxicity Identification Evaluations (TIEs). Despite this, microalgae have not previously been used in marine TIE studies. In this study, the marine diatom Nitzschia closterium was shown to be a highly suitable test organism after modification of the standard test protocol to reduce test volumes to 6 mL and test duration to 48 h. The alga was tolerant to the chemicals used in phase I of the standard USEPA TIE protocol, and physical TIE manipulations had no effect on algal growth. The cation exchange procedure, however, inhibited algal growth, while the anion exchange procedure stimulated growth, making these two procedures unsuitable for use with this species. Of the buffers trialed for the graduated pH procedure, 0.01 M PIPES buffer was found to be suitable for buffering at pH 7 because it maintained the required pH over the duration of the test and did not affect the growth or sensitivity of the algae to one reference toxicant (copper). A trial TIE on a secondary-treated sewage effluent for discharge into coastal waters showed that the developed protocols could successfully be used to identify ammonia as the major toxicant in the effluent.

Biomechanical comparison of anterior cervical plating and combined anterior/lateral mass plating

BACKGROUND CONTEXT

Previous studies showed anterior plates of older design to be inadequate for stabilizing the cervical spine in all loading directions. No studies have investigated enhancement in stability obtained by combining anterior and posterior plates.

PURPOSE

To determine which modes of loading are stabilized by anterior plating after a cervical burst fracture and to determine whether adding posterior plating further significantly stabilizes the construct.

STUDY DESIGN/SETTING

A repeated-measures in vitro biomechanical flexibility experiment was performed to investigate how surgical destabilization and subsequent addition of hardware components alter spinal stability.

PATIENT SAMPLE

Six human cadaveric specimens were studied.

OUTCOME MEASURES

Angular range of motion (ROM) and neutral zone (NZ) were quantified during flexion, extension, lateral bending, and axial rotation.

METHODS

Nonconstraining, nondestructive torques were applied while recording three-dimensional motion optoelectronically. Specimens were tested intact, destabilized by simulated burst fracture with posterior distraction, plated anteriorly with a unicortical locking system, and plated with a combined anterior/posterior construct.

RESULTS

The anterior plate significantly (p<.05) reduced the ROM relative to normal in all modes of loading and significantly reduced the NZ in flexion and extension. Addition of the posterior plates further significantly reduced the ROM in all modes of loading and reduced the NZ in lateral bending.

CONCLUSIONS

Anterior plating systems are capable of substantially stabilizing the cervical spine in all modes of loading after a burst fracture. The combined approach adds significant stability over anterior plating alone in treating this injury but may be unnecessary clinically. Further study is needed to assess the added clinical benefits of the combined approach and associated risks.

Development of an improved rapid enzyme inhibition bioassay with marine and freshwater microalgae using flow cytometry

A rapid toxicity test based on inhibition of esterase activity in marine and freshwater microalgae (Selenastrum capricornutum, Chlorella sp., Dunaliella tertiolecta, Phaeodactylum tricornutum, Tetraselmis sp., Entomoneis cf. punctulata, Nitzschia cf. paleacea) was developed using flow cytometry. Uptake of fluorescein diacetate (FDA) was optimized for each species by varying the substrate concentration, incubation time, and media pH. Propidium iodide (PI) was utilized to assess membrane integrity. The optimized FDA/PI staining procedure was then used to assess the toxicity of copper in short-term exposures (1-24 h). Esterase activity was a sensitive indicator of copper toxicity in S. capricornutum and E. cf. punctulata. As copper concentrations increased, esterase activity decreased in a concentration-dependent manner. The 3- and 24-h EC50 values (based on mean activity states) were 112 microg Cu L(-1) (95% confidence limits 88-143) and 51 microg Cu L(-1) (95% confidence limits 38-70) for S. capricornutum and 47 microg Cu L(-1) (95% confidence limits 43-51) and 9.1 microg Cu L(-1) (95% confidence limits 7.6-11) for E. cf. punctulata, respectively. This enzyme inhibition endpoint showed similar sensitivity to chronic growth rate inhibition in E. cf. punctulata (48-h and 72-h EC50 values of 17 and 18 microg L(-1), respectively) but was less sensitive compared to growth for S. capricornutum (48-h and 72-h EC50 values of 4.9 and 7.5 microg L(-1), respectively). For the other five species tested, inhibition of FDA fluorescence was relatively insensitive to copper, even at copper concentrations that severely inhibited cell division rate. These short-term bioassays that detect sublethal endpoints may provide a more rapid and cost-effective way of monitoring contaminant impacts in natural waters.

An outbreak of rubella in British troops in Bosnia

An outbreak of rubella in April 1996 involved four male British soldiers deployed to Bosnia-Herzegovina. All were helicopter ground crew who were members of the same unit and who periodically travelled to and worked at forward air refuelling stations in Bosnia. There was a potential for spread of the infection to adjacent British units, to troops of other nations in the peacekeeping force, and also to the local civilian population. The British force included 620 female personnel, some of whom may have been non-immune to rubella. One pregnant British servicewoman was repatriated to UK for her own protection. There was a potential health risk, including the possibility of congenital rubella syndrome, in the non-immune wives and partners of deployed male personnel, as a result of contact during the mid-tour home leave of the husbands or partners. The outbreak was monitored through a medical surveillance system known as ARRC 97, and was contained by prompt and rigorous control measures. This outbreak shows the importance of effective surveillance and of good microbiology laboratory support during military operations. The role of immunization against rubella during future military deployments is discussed.

Sports injuries in British troops deployed on Operation Resolute (Bosnia)

This study presents epidemiological data on sports injuries in deployed British troops in Bosnia, during the first five months of Operation Resolute. A retrospective analysis was carried out of sports injuries seen in one practice in the divisional rear area during April 1996. They account for a significant morbidity in deployed troops and are a major cause of manpower wastage and of medical repatriations. The continuous monitoring of sports injury should be a central part of the epidemiological surveillance of deployed troops. Their occurrence during operations can be minimised by judicious restrictions on those sports, such as football, which are known to have an adverse injury profile.

Pre-existing disease in British Army patients aeromedically evacuated from the former Republic of Yugoslavia

A questionnaire study was carried out on 74 British Army patients who were awaiting aeromedical evacuation from the Former Republic of Yugoslavia. The study confirmed previous unpublished reports that 41% of patients were being repatriated for exacerbation of pre-existing disease. Of these, 78% had disease known to their medical officer, were considered to be outside limits for full fitness, according to accepted military standards, but had not been downgraded. Only 34% of these patients had been reviewed prior to deployment to assess their fitness. Assessment of fitness to deploy was in some cases based on inaccurate information about in theatre living and working conditions, and the medical support available. In conclusion it would appear that medical officers should be more diligent in downgrading unfit personnel to prevent their deployment on operations thereby reducing the burden on the medical evacuation chain. Medical officers need up-to-date information on operational areas in order to make appropriate decisions on fitness of personnel to deploy.

A comparison of the pathophysiologic effects of carbon dioxide, nitrous oxide, and helium pneumoperitoneum on intracranial pressure

BACKGROUND

Previous studies have suggested that diagnostic laparoscopy may be contraindicated in multiple trauma patients with closed head injuries because of the detrimental effects of carbon dioxide (CO2) pneumoperitoneum on intracranial pressure (ICP). In this study we compared the effects of two alternative inflation gases, helium (He) and nitrous oxide (N2O), against the standard agent used in most hospitals, CO2. ICP was monitored in experimental animals both with and without a space occupying intracranial lesion designed to simulate a closed head injury.

METHODS

Twenty-four domestic pigs (mean, 30 kg) were divided into four groups (6 CO2, 6 He, 6 N2O, and 6 control animals without insufflation). All animals were monitored for ICP, intraabdominal pressure, mean arterial pressure, end-tidal CO2 (ETCO2), and arterial blood gases. These parameters were measured for 30 minutes prior to introducing a pneumoperitoneum and then for 80 minutes thereafter. The measurements were repeated after artificially elevating the ICP with a balloon placed in the epidural space.

RESULTS

The mean ICP increased significantly in all groups during peritoneal insufflation compared with the control group (P < 0.005). The CO2-insufflated animals also showed a significant increase in PaCO2 (P < 0.05) and ETCO2 (P < 0.05), as well as a decrease in pH (P < 0.05). After inflating the epidural balloon the ICP remained significantly higher in animals inflated with CO2 as compared with the He and N2O groups (P < 0.05).

CONCLUSIONS

Peritoneal insufflation with He and N2O resulted in a significantly less increase in ICP as compared with CO2. That difference was most likely due to a metabolically mediated increase in cerebral perfusion (PaCO2) in the CO2 group. Further studies need to be conducted to determine the safety and efficacy of using He and N2O as inflation agents prior to attempting diagnostic or therapeutic laparoscopy in patients with potential closed head injuries.

A comparison of fluoroscopy and computed tomography-derived volumetric multiple exposure transmission holography for the guidance of lumbar pedicle screw insertion

Holographic technology has recently been modified in such a manner that it may now provide clinical use. It allows the visualization of complex structures in three dimensions and permits clinician interaction with the image, which, in turn, provides significant additional geometric and anatomic information. To objectively assess the potential clinical applicability of holography in pedicle screw placement, we studied 11 elderly human cadavers. All of the cadavers, each of which showed significant degenerative disease of the lumbar spine, underwent thin-section computed tomographic scans of the lumbar spine. The acquired digital information was processed, and volumetric multiple exposure transmission holographic images were rendered. Pedicle screws were passed into anatomically acceptable and radiographically visualized L3-L5 pedicles in each cadaver, half using fluoroscopic guidance and half using holographic guidance alone. The accuracy of screw placement was objectively assessed by a three-point grading scale. The total score for the placement of each pedicle screw was determined by both trajectory (location within the pedicle) and accuracy (containment within the vertebral body) of screw tip placement parameters. Three points were possible for each screw placed. Screw placement in the last six cadavers was individually timed for each technique, and fluoroscopic time was also recorded. Each technique was used on 27 pedicles. The total score for fluoroscopic screw placement was 71 (71 of a possible 81; 88%) and for holographic screw placement was 74 (74 of a possible 81; 91%). In the last six cadavers, the screw placement time (per cadaver) was 8 minutes for fluoroscopic placement and 3.6 minutes for holographic placement. Fluoroscopic time averaged 1.9 minutes per cadaver.(ABSTRACT TRUNCATED AT 250 WORDS)

Anatomy of the thoracic pedicle

Thoracic pedicle anatomy (interpedicular distance, transverse and sagittal pedicle widths, transverse and sagittal pedicle angles, and the distance from the axis of the pedicle to the axis of the transverse process) was assessed in 11 cadavers of elderly people. The cadaveric spines were extensively dissected to augment the accuracy of the measurements via caliper and goniometer. The results were compared with those of previous studies that assessed pedicle anatomy with computed tomography, direct measurement, and three-dimensional morphometry. Between the studies, significant differences were found in transverse pedicle width and transverse and sagittal pedicle angles. These morphometric differences may reflect either the diversity of the techniques used to measure the pedicle anatomy or sampling variation. This article presents a previously unreported morphometric finding, the rostral-caudal distance from the thoracic pedicle to the midpoint of the base of the transverse process. At T1, the transverse process is 5.45 +/- 1.2 mm rostral to the pedicle. This relationship gradually changes as the thoracic spine is descended, so that at T12, the transverse process is 6.6 +/- 2.4 mm caudal to the pedicle. Crossover consistently occurs at the T6-T7 region. Although the transverse process is a reliable external landmark for the location of the pedicle in the lumbar spine, this relationship in the thoracic spine is variable and only moderately predictable.

Doppler color flow mapping of epicardial coronary arteries: initial observations

OBJECTIVES

We addressed the hypothesis that blood flow could be imaged by Doppler color flow mapping of the coronary arteries and characteristic patterns described in normal and diseased vessels.

BACKGROUND

Echocardiographic imaging of the epicardial coronary arteries has been suggested as a useful adjunct to their intraoperative evaluation. Addition of Doppler color flow mapping could potentially enhance this evaluation by displaying the flow disturbance produced by anatomic lesions whose physiologic significance may otherwise be uncertain. In experimental models, such displays could also potentially provide insights into the pathophysiology of coronary blood flow and stenosis.

METHODS

Epicardial coronary arteries were examined with a high resolution 7-MHz linear phased-array transducer both in vivo and in vitro. 1) The coronary arteries were studied in the beating hearts of 10 open chest dogs in which experimental stenoses were also created; the maximal extent of the arterial tree in which flow could be seen in the most ideal setting was also examined in four additional excised perfused canine hearts. 2) Six excised human coronary arteries were perfused in a pulsatile manner to determine whether abnormal flow patterns could be prospectively identified and subsequently correlated with pathologic evidence of stenosis.

RESULTS

All normal coronary artery segments studied showed homogeneous flow without evidence of flow disturbance. In the excised heart, flow could be visualized to the distal extent of the epicardial vessels; in the open chest model, visualization of the proximal 5 to 6 cm was comparable, although surrounding structures limited access to the terminal portions of the vessels. The stenotic lesions created in the canine hearts (n = 9) showed recognizable alterations in the flow pattern: localized aliasing, proximal blood flow acceleration, distal flow disturbance and recirculatory flow. In the excised human arteries, these features identified 12 lesions, all of which corresponded to areas of > or = 50% lumen narrowing by pathologic examination.

CONCLUSION

Blood flow in the epicardial coronary arteries can be imaged by Doppler color flow mapping and characteristic flow patterns described in normal and diseased vessels.

Personality traits and behaviors of alcohol-impaired drivers: a comparison of first and multiple offenders

Using an interview and questionnaire format, 358 driving under the influence of alcohol (DUI) first offenders and 141 DUI multiple offenders were compared on measures of personality traits, drinking behavior and problems, and driving behavior and history. In addition, official driving records for the two groups were compared. Results indicated that multiple offenders were significantly higher in hostility, sensation seeking, psychopathic deviance, mania, and depression than first offenders. Multiple offenders were significantly lower in emotional adjustment and assertiveness. Multiple offenders had significantly more nontraffic arrests, accidents, and traffic tickets than first offenders. They also consumed significantly more alcohol, evidenced more alcohol problems, and had higher BACs at the time of arrest than first offenders. Results are discussed in terms of general problem behavior and implications for intervention and treatment.

Management of attention deficit disorders

Attention deficit disorders are not uncommon in the clinics and office practice of child psychiatrists. The diagnosis, evaluation, and comprehensive treatment of this disorder are discussed.

Cost containment in a community mental health center

Faced with a major operational deficit and the end of its federal staffing grant, a community mental health center established a cost-containment committee and developed a program to engage staff support. The committee, including members of the clinical and administrative staffs and the community board, meets weekly to review requests for expenditures. In its first 11 months, it completed action on 212 requests and returned many others for further justification. Most cost savings were in the area of personnel, through such steps as nonreplacement of staff, replacement with less senior staff, and position consolidation. Other results of the committee's activities have been greater staff productivity, an increase in third-party payments, establishment of various personnel guidelines, and the acquisition of additional county funds to help cover the deficit from the termination of the staffing grant.

Ego functioning during latency

The latency period is an extremely important transition between the preschool years and adolescence. Normal ego functioning is described, especially cognition, socialization, motor development, and defensive functions.

Becoming an independent Community Mental Health Center: perils of the process

Over the past 12 years, since the inception of the Community Mental Health Center (CMHC) movement, there has been increasing concern that local communities have more input; in fact, that they actually have the opportunity to operate the mental health programs that they deem necessary for their communities.(1)Under the Amendments to the Community Mental Health Act (P.L.94-63) 1975, CMHCs were given such options as independence or governance. The whole process of governance presents numerous problems as well as opportunities. An overview of the vicissitudes of this process is presented in this paper.

Reflections on short-term psychiatric hospitalization for children and adolescents

The functions and operations of a short-term psychiatric inpatient unit for children and adolescents are discussed. Staffing pattern, programming, and statistical data are reviewed. The author concludes that short-term inpatient treatment has much to offer when complemented by careful research and evaluation.

Centralized vs. decentralized child mental health services

One of the basic tenets of the Community Mental Health Center movement is that services should be provided in the consumers' community. Various centers across the country have attempted to do this in either a centralized or decentralized fashion. Historically, most health services have been provided centrally, a good example being the traditional general hospital with its centralized medical services. Over the years, some of these services have become decentralized to take the form of local health centers, health maintenance organizations, community clinics, etc, and now various large mental health centers are also being broken down into smaller community units. An example of each type of mental health facility is delineated here.

Pitfalls in adolescent day treatment programming

The concept of the adolescent day treatment program offers many exciting treatment possibilities. This paper is an attempt to outline some of the potential problems or pitfalls which can occur in developing such a program. The author stresses the importance of having a program philosophy and indicates various aspects of the program which need careful planning and implementation.

Multiple congenital anomalies associated with a ring-D chromosome

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