Association of calcium intake, dairy product consumption with overweight status in young adults (1995-1996): the Bogalusa Heart Study.

OBJECTIVE: To examine the association between calcium intake and dairy product consumption with overweight and obesity in young adults. METHODS: The sample used in this study consisted of 1306 young adults, ages 19-38 years, who participated in the 1995-1996 young adult survey. Analysis was performed with analysis of covariance (ANCOVA) for ethnicity-gender groups separately. RESULTS: No significant association was found between dairy product consumption, calcium intake and overweight, defined by body mass index or waist circumference. However, there was a significant inverse association between calcium intake, low-fat dairy product consumption and waist-to-hip ratio in white males. CONCLUSION: Increasing intake of calcium and low-fat dairy products may be associated with lower abdominal adiposity, particularly in young adult white males.

Assessing stroke patients' prospective memory using virtual reality.

There is a dearth of empirical evidence about prospective memory (remembering to perform actions in the future) in stroke patients. A probable reason for this is that it is difficult to perform a realistic and controlled assessment of prospective memory ability in a rehabilitation setting. Virtual reality may provide a solution to this difficulty by allowing prospective memory to be tested in a simulation of a real-life situation whilst retaining a laboratory level of scientific control. This exploratory study assessed the performance of stroke patients and age-matched control participants on event-, time- and activity-based prospective memory retrieval tasks in a personal computer-based virtual environment. Stroke patients were severely impaired at the event- and activity-based tasks compared with age-matched controls, but only marginally impaired at the time-based task. The additional knowledge gained from this form of assessment could direct rehabilitation more effectively towards specific impairments of individual patients.

Age and recovery from brain injury: legal opinions, clinical beliefs and experimental evidence.

Despite considerable scientific evidence to the contrary, many medical practitioners maintain that children recover from brain injury better than adults. This belief, which is commonly referred to as the "Kennard Principle", has important ramifications for personal injury compensation claims in which the amount of financial damages claimed is partly based on medical experts' prognoses for recovery and long-term outcome. The present study investigated whether legal practitioners' beliefs are consistent with those of medical practitioners. Lawyers were asked to estimate their confidence in consultant neurologists' estimates of recovery in four clinically-based but fictitious case studies which differed only in the reported age of the patient. The lawyers showed more confidence in estimates which coincided with the Kennard Principle than those which did not. These results support previous findings in showing widespread belief that "younger is better" in recovery from brain injury. In consequence, it is likely that financial compensation for children with brain injury is currently being underestimated in litigation, thereby prejudicing the long-term outcome of the child.

The use of virtual reality in memory rehabilitation: current findings and future directions.

There is considerable potential for using virtual reality (VR) in memory rehabilitation which is only just beginning to be realized. PC-based virtual environments are probably better suited for this purpose than more immersive virtual environments because they are relatively inexpensive and portable, and less frightening to patients. Those exploratory studies that have so far been performed indicate that VR involvement would be usefully directed towards improving assessments of memory impairments and in memory remediation using reorganization techniques. In memory assessment, the use of VR could provide more comprehensive, ecologically-valid, and controlled evaluations of prospective, incidental, and spatial memory in a rehabilitation setting than is possible using standardized assessment tests. The additional knowledge gained from these assessments could more effectively direct rehabilitation towards specific impairments of individual patients. In memory remediation, VR training has been found to promote procedural learning in people with memory impairments, and this learning has been found to transfer to improved real-world performance. Future research should investigate ways in which the procedural knowledge gained during VR interaction can be adapted to offset the many disabilities which result from different forms of memory impairment.

Benzylpenicillin differentially conjugates to IFN-gamma, TNF-alpha, IL-1beta, IL-4 and IL-13 but selectively reduces IFN-gamma activity.

It is known that beta-lactam antibiotics can conjugate to lysine and histidine residues on proteins via the carbonyl group of the opened beta-lactam ring. However, it is not known which proteins these drugs target and there is little work addressing whether conjugation is preferential for some proteins over others or if conjugation has functional consequences for the protein. We have previously shown that the beta-lactam antibiotic benzylpenicillin (BP) conjugates to IFN-gamma and reduces its activity. This interaction demonstrates selectivity, as BP does not bind to IL-4. Here, we extend our study to include other Th1 and Th2 cell-associated cytokines and two cytokines associated with inflammatory responses. We demonstrate by Western blotting that BP also conjugates to IL-1beta, IL-2, IL-5, IL-13 and TNF-alpha but not to IL-10. Densitometric analysis of leading cytokine bands on blots revealed that IFN-gamma always gave more intense BP-positive bands than any other cytokine analysed. Cytokines pre-incubated with BP at 37 degrees C in a protein-containing, serum-free medium were assayed for their biological activity. By in vitro bioassay, BP inhibited the ability of IFN-gamma but not IL-1beta or TNF-alpha to induce CD54 expression on epithelial cells. In addition, BP did not affect IL-4 or IL-13 inhibition of mast cell proliferation. When the pre-incubation temperature was reduced to 4 degrees C, BP did not conjugate to IFN-gamma or modulate its activity. BP retained its inhibitory effect on IFN-gamma activity when 20% FCS was added to the pre-incubation medium. In conclusion, BP conjugates to some cytokines but not others and this does not appear to be related to primary protein structure. Furthermore, of the cytokines studied, conjugation only to IFN-gamma is accompanied by inhibition of activity. This phenomenon is temperature dependent and occurs in the presence of serum. These findings provide further evidence for differential, direct drug-cytokine interactions. Such interactions may have therapeutic implications in terms of targeting cytokines to regulate their activity.

Support for children following traumatic brain injury: the views of educational psychologists.

PURPOSE: For many years, neuroscientific research appeared to support the view that the young brain was more resilient and better able to withstand damage than the mature brain. More recent neuroscience research has questioned this view. Nevertheless, the view that 'younger is better' continues to be accepted by many medical practitioners. The present study sought to establish whether the training and experience of educational psychologists has made them aware that young children are particularly vulnerable to long-term effects of brain injury. METHOD: Educational psychologists were asked to estimate the need for additional social/family and educational support, and how long such additional support would be needed, in four fictitious but clinically-based case studies which differed only in the reported age of the child/adolescent at the time of the injury. RESULTS: Educational psychologists consistently rated young children with brain injuries as needing more additional social/family support for longer than adolescents. CONCLUSIONS: These results suggest that there is an appreciation of the additional needs of young children who have sustained brain injuries within our educational system.

An evaluation of the efficacy of training people with learning disabilities in a virtual environment.

PURPOSE: To evaluate the efficacy of using a virtual kitchen for vocational training of people with learning disabilities. METHOD: Twenty four catering students with learning disabilities participated in the study. Half the students were currently being trained in the kitchen on which the virtual kitchen was modelled but the remaining students were unfamiliar with this kitchen. Students were first pre-tested on four food preparation tasks and identification of 12 hazards in their own training kitchens. They were subsequently trained on one food preparation task and three hazards in their own training kitchens, one food preparation task and three hazards in the virtual kitchen, and one food preparation task and three hazards in specially designed workbooks. They were then retested in their own training kitchens on all the food preparation tasks and all the hazards. RESULTS: Virtual training was found to be as beneficial as real training and more beneficial than workbook and no training in the food preparation tasks. However, virtual, real and workbook training were found to be equally beneficial in the hazard identification task. Students who were unfamiliar with the kitchen on which the virtual kitchen was modelled benefited from virtual training to the same extent as students who were familiar with the kitchen. CONCLUSIONS: Vocational students with learning disabilities were able to use the virtual environment and were motivated to learn using this training method. Depending on the task being trained, virtual training had a more beneficial effect on real task performance than workbook training, even when the virtual kitchen was not modelled on the real training kitchen.

An exploratory investigation into the usability and usefulness of training people with learning disabilities in a virtual environment.

PURPOSE: Two studies sought to answer the following questions. Are people with learning disabilities capable of using a virtual environment? Are they motivated to learn using this training method? Do they show any benefit from using a virtual environment? Does any benefit transfer to improved real world performance? METHOD: In the first study, 30 students with learning disabilities were sequentially allocated to an active or a passive experimental group. Active participants explored a virtual bungalow searching for a toy car. Passive participants watched the exploration undertaken by the preceding active participant and searched for the toy car. All participants then performed spatial and object recognition tests of their knowledge of the virtual environment. In the second study, the errors of 45 participants on a real steadiness tester task were noted before they were randomly allocated to three groups-a real training group, a virtual training group and a no training group. After training, the participants performed a second test trial on the real steadiness tester. RESULTS: The students were capable of using a virtual environment and were motivated to use this training method. Active exploration of a virtual environment was found to enhance their memory of the spatial layout of the bungalow but not their memory of the virtual objects. In the second study, virtual training was found to transfer to real task performance. CONCLUSIONS: These two laboratory-based studies provide answers to four important questions concerning virtual training of people with learning disabilities. Hopefully, the findings will encourage this training aid to be used more widely.

Penicillin conjugates to interferon-gamma and reduces its activity: a novel drug-cytokine interaction.

Beta-lactam antibiotics are the class of drug most frequently associated with IgE-mediated allergy but the mechanisms underlying this response are poorly understood. IFN-gamma is a key cytokine in immunity with regulatory actions on monocytes, NK cells, epithelial cells, and T and B lymphocytes. IFN-gamma promotes Th1 responses and inhibits Th2- and IgE-mediated responses. In this study we show, by Western blotting, that the prototype beta-lactam benzylpenicillin (BP) conjugates to human IFN-gamma but not to IL-4. The interaction of BP with IFN-gamma inhibited the cytokine's detection by immunoassay and impaired its activity, as assessed in three different assays: upregulation of MHC molecules on monocytes plus induction of nitric oxide synthesis and expression of monocyte chemoattractant protein-1 mRNA by epithelial cells. This is the first reported example of a direct drug-cytokine interaction and suggests a mechanism by which penicillin may disrupt IFN-gamma-dependent immune responses and promote allergy.

Training in virtual environments: transfer to real world tasks and equivalence to real task training.

Virtual environments (VEs) are extensively used in training but there have been few rigorous scientific investigations of whether and how skills learned in a VE are transferred to the real world. This research aimed to measure and evaluate what is transferring from training a simple sensorimotor task in a VE to real world performance. In experiment 1, real world performances after virtual training, real training and no training were compared. Virtual and real training resulted in equivalent levels of post-training performance, both of which significantly exceeded task performance without training. Experiments 2 and 3 investigated whether virtual and real trained real world performances differed in their susceptibility to cognitive and motor interfering tasks (experiment 2) and in terms of spare attentional capacity to respond to stimuli and instructions which were not directly related to the task (experiment 3). The only significant difference found was that real task performance after training in a VE was less affected by concurrently performed interference tasks than was real task performance after training on the real task. This finding is discussed in terms of the cognitive load characteristics of virtual training. Virtual training therefore resulted in equivalent or even better real world performance than real training in this simple sensorimotor task, but this finding may not apply to other training tasks. Future research should be directed towards establishing a comprehensive knowledge of what is being transferred to real world performance in other tasks currently being trained in VEs and investigating the equivalence of virtual and real trained performances in these situations.

A preliminary investigation into the use of virtual environments in memory retraining after vascular brain injury: indications for future strategy?

PURPOSE: In a preliminary investigation of the use of Virtual Environments (VEs) in neurorehabilitation, this study compares the effects of active and passive experience of a VE on two types of memory in vascular brain injury patients and controls. METHOD: Forty-eight patients with vascular brain injury and 48 non-impaired control participants were randomly assigned to active and passive VE conditions. The active participants explored a virtual bungalow seeking a particular object; the passive participants observed, but did not control movement through the VE, also seeking the object. Afterwards, both active and passive participants completed spatial recognition and object recognition tests. RESULTS: Expectedly, the patients were impaired relative to the controls but were able to perform the virtual tasks. Active participation in the VE enhanced memory for its spatial layout in both patients and controls. On object recognition, active and passive patients performed similarly, but passive controls performed better than active controls. CONCLUSIONS: The findings are discussed in relation to their implications for memory rehabilitation strategies.

Primacy and recency in primed free association and associative cued recall.

Two experiments compared the serial positions of primed words in an implicit free association test with words recalled in a cued recall test. In both tests, weakly or strongly related word pairs were studied, and the first words of each pair formed the test cues. In the implicit test, weakly related words pairs showed primacy and extended recency effects but strongly related word pairs did not. In the explicit test, both weakly and strongly related word pairs showed primacy and extended recency effects. These functional dissociations between implicit and explicit memory tests indicate that strongly related word pairs are encoded together because they have unitized memory representations that function as integrated units without requiring any additional associative links to be made, but that an additional system or process is required to strengthen weakly related word pairs during encoding. In addition, a further additional system or process is accessed by explicit retrieval.

The specificity of memory enhancement during interaction with a virtual environment.

Two experiments investigated differences between active and passive participation in a computer-generated virtual environment in terms of spatial memory, object memory, and object location memory. It was found that active participants, who controlled their movements in the virtual environment using a joystick, recalled the spatial layout of the virtual environment better than passive participants, who merely watched the active participants' progress. Conversely, there were no significant differences between the active and passive participants' recall or recognition of the virtual objects, nor in their recall of the correct locations of objects in the virtual environment. These findings are discussed in terms of subject-performed task research and the specificity of memory enhancement in virtual environments.

Virtual environments in brain damage rehabilitation: a rationale from basic neuroscience.

The potential of virtual environments in assessment and training of cognitive function is a more than adequate reason for their application to neurorehabilitation. However, there is a more fundamental justification, and one which is firmly rooted in the neuroscience literature. Over the last half century there has been a wealth of published evidence that enriching the environments of laboratory rats stimulates neuroplastic change in the cerebral cortex, enhances learning and problem solving in normal rats and reduces cognitive impairment in brain damaged rats. Central to all three effects of enrichment are the increased levels of interaction with the physical environment engendered by enrichment. Placing humans who have damaged brains in virtual environments is one way of enhancing their levels of environmental interaction which, because of cognitive impairments and sensory and motor disabilities, is otherwise difficult to achieve. In this chapter we explore the potential of virtual environments as enriched environments within the rehabilitation regime. The underlying assumption, that interaction with a virtual environment is functionally equivalent to interaction with a real environment, is examined. Three lines of relevant evidence are reviewed, neuroimaging studies and psychophysiological studies of people in virtual environments and studies of transfer of training from virtual to real tasks. An agenda for future research in this are is proposed.

Virtual environments in neuropsychological assessment and rehabilitation.

Brain damage constitutes a major problem for those affected, for their families and friends and for society as a whole. The need for effective rehabilitation strategies is clear. Yet, until the early 1960s, the brain was generally considered to be a somewhat fixed and inflexible organ. In consequence the impairments associated with brain damage were generally regarded as "incurable". Since that time neuroscientists have had reason to change their views dramatically. However, much remains to be done. Progress depends upon a co-ordinated multidisciplinary approach within which assistive technology will be a key player. Within the area of assistive technology, one of the developments which holds particular promise for the field of neurological rehabilitation is the computer technology underlying virtual environments (commonly known as virtual reality). In this chapter we describe the new opportunities offered by virtual reality to pursue several aspects of the rehabilitation process. The value of the technology of virtual environments in this context is that it allows us to immerse people with brain damage in relatively realistic interactive environments which, because of their patterns of impairment, would otherwise be unavailable to them.

Age differences in memory for prospective compared with retrospective subject-performed tasks.

In two experiments, younger and older adults studied three lists of verbal phrases, each of the latter describing a simple action. One list was studied and recalled verbally; one was recalled verbally, but the actions were performed at study [retrospective SPTs (subject-performed tasks)]; and one was studied verbally and the actions were performed at test (prospective SPTs). With long lists, but not with short ones, retrospective-SPT recall exceeded verbal recall and older adults recalled fewer SPTs than did younger adults. Prospective-SPT recall did not exceed verbal recall at either list length, and in each of these prospective-SPT tests, older adults recalled fewer action phrases than did younger adults. Thus, it appears that when retrospective and prospective tasks are equated there are marked age differences that are generally consistent with the view that memory impairment in the elderly is more likely to occur in tasks that make higher attentional processing demands.

A comparison of serial position effects in implicit and explicit word-stem completion.

In this study I examined a further possible dissociation between implicit and explicit memory-whether implicit memory produces serial position effects that are similar to those found in explicit memory. When implicit word-stem completion and explicit word-stem cued recall were compared, only the explicit test showed significant primacy and recency effects. The explicit test was sensitive to the order in which stimuli words were encoded, but the implicit test was not. This dissociation between implicit and explicit memory provides further evidence that conscious retrieval processes were not involved in the implicit test.