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Biomedical subjects

M J Harrison

Publications and source records attributed to M J Harrison.

At least 37 records · Page 2Linked to original sources
PubMed2001

Tracking the early acquisition of skills by trainees.

A form of sequential analysis has been developed to track performance of tracheal intubation by novice intubators. One hundred and nineteen trainees completed logbooks during their attachment to the Departments of Anaesthesia and these data were used to produce rates of success for sequential attempts at the procedure. A grid was created from this on which future trainees could report their performance. A boundary drawn on the grid can be used as a trigger to indicate the need for more basic instruction.

Anesthesiology↗
PubMed2001

The spatial expression patterns of a phosphate transporter (MtPT1) from Medicago truncatula indicate a role in phosphate transport at the root/soil interface.

The movement of phosphate from the soil into plant root cells is the first of many crucial transport events required to supply phosphorous (P) to cells throughout the plant. In addition to the ability to acquire phosphate from the soil, the majority of the vascular plants are able to form arbuscular mycorrhizal associations in which phosphate may be delivered to the cortex via a fungus. Previously, we cloned two phosphate transporter genes, MtPT1 and MtPT2 from Medicago truncatula roots. Complementation of a yeast phosphate transport mutant revealed that MtPT1 is a functional phosphate transporter and Northern analyses revealed that MtPT1 is expressed exclusively in roots (Liu et al., 1998, Mol. Plant-Microbe Interact. 11, 14--22). Utilising an antibody specific for MtPT1, we have analysed the accumulation and spatial expression patterns of the MtPT1 transporter. MtPT1 transcript and protein levels show close correlation and increase dramatically in the roots in response to phosphate starvation. MtPT1 protein levels decrease in roots during development of a symbiosis with arbuscular mycorrhizal (AM) fungi, indicating that this transporter is not involved in symbiotic phosphate transport. Membrane fractionation and analysis of a MtPT1/GFP fusion protein revealed that MtPT1 is located in the plasma membrane, while in situ hybridisation and immunolocalisation demonstrate the presence of MtPT1 transcripts and protein in the epidermal cells and root hairs of M. truncatula roots. MtPT1 shows expression patterns consistent with a role specifically in the acquisition of phosphate from the soil and is distinct from the other phosphate transporter of this class described to date.

Antibody Specificity↗
PubMed2001

Psychosocial interventions for caregivers of people with dementia: a systematic review.

The content of interventions for caregivers of dementia patients is highly varied. None of the reviews conducted to date have focused on evaluating the effects of the content of interventions exclusively for dementia caregivers, and this issue is not well understood. The purpose of this review was to first identify the type of components (e.g. education, counselling) that have been utilized in psychosocial/psycho-educational interventions for dementia caregivers, and to evaluate the success of the different components or combination of components in producing positive outcomes for dementia caregivers. Forty studies were included in the review. Approximately two-thirds of the interventions did not show improvements in any outcome measures. Among those studies, which did demonstrate improvements, the inclusion of social components (e.g. social support) or a combination of social and cognitive (e.g. problem solving) components seemed to be relatively effective. It is important to note, however, that these analyses were based on small numbers and the review was limited by a number of methodological issues (e.g. poor description of interventions). To advance our understanding of the efficacy of psychosocial interventions for caregivers of people with dementia, a more systematic approach is required. Intervention components need to be carefully contrasted in appropriately designed studies of sufficient size.

Adaptation, Psychological↗
PubMed2001

A phosphate transporter gene from the extra-radical mycelium of an arbuscular mycorrhizal fungus Glomus intraradices is regulated in response to phosphate in the environment.

The majority of vascular flowering plants are able to form symbiotic associations with arbuscular mycorrhizal fungi. These symbioses, termed arbuscular mycorrhizas, are mutually beneficial, and the fungus delivers phosphate to the plant while receiving carbon. In these symbioses, phosphate uptake by the arbuscular mycorrhizal fungus is the first step in the process of phosphate transport to the plant. Previously, we cloned a phosphate transporter gene involved in this process. Here, we analyze the expression and regulation of a phosphate transporter gene (GiPT) in the extra-radical mycelium of the arbuscular mycorrhizal fungus Glomus intraradices during mycorrhizal association with carrot or Medicago truncatula roots. These analyses reveal that GiPT expression is regulated in response to phosphate concentrations in the environment surrounding the extra-radical hyphae and modulated by the overall phosphate status of the mycorrhiza. Phosphate concentrations, typical of those found in the soil solution, result in expression of GiPT. These data imply that G. intraradices can perceive phosphate levels in the external environment but also suggest the presence of an internal phosphate sensing mechanism.

Biological Transport↗
PubMed2001

Participation of immigrant women family caregivers in qualitative research.

The recruitment of articulate, expressive participants is an essential part of methodology in qualitative research. This article presents the authors' experience in the recruitment of immigrant women of Chinese and South Asian origin in an ethnographic study. The study included women caring for an adult or child family member who had a chronic health problem. Knowledge of women family caregivers' health is restricted by the failure to include diverse groups of women in research. In this article, the authors discuss issues related to recruitment and participation of immigrant women in research, including establishing access to diverse groups of women, benefits for immigrant women, and placing the researcher and research process on the same level. Practical research strategies to address these issues and engage the women in research that portrays their perspectives are presented. The authors' discussion concludes with reflection on their experience and that of other researchers.

Adult↗
PubMed2001

The use of leucocyte-depleting and conventional arterial line filters in cardiac surgery: a systematic review of clinical studies.

Although various forms of arterial line filter have been available for use during cardiopulmonary bypass (CPB) for 30 years, their use is not universal. The aim of this review was to seek evidence of the clinical benefit of using conventional or leucocyte-depleting arterial line filters during bypass. A literature search revealed 28 relevant clinical studies. Despite the wide variety of patient populations, types of filter and outcome measures utilized in studies, a few conclusions are possible. Whereas conventional filtration has the definite effect of reducing neuropsychological deficit post-CPB, the results of studies using the leucocyte-depleting filter are less clear cut. Leucocyte-depleting filters have potential for reducing inflammatory mediated heart and lung injury, however it is recommended that any additional benefit of leucocyte-depleting filters over conventional filters should be further tested by randomized controlled trials of sufficient size.

Cardiopulmonary Bypass↗
PubMed2000

What nursing home residents value in their doctors.

Patient satisfaction is influenced by multiple factors, and different populations are expected to define satisfaction in terms of their novel perspectives. Despite growing interest in patient satisfaction, an extensive literature search reveals no studies of nursing home residents' satisfaction with respect to medical care. In an initial qualitative study using transcripts of interviews conducted as part of a state quality control mandate, categories are identified that make up this population's construct of satisfaction and dissatisfaction. These categories serve as building blocks for designing future studies investigating these issues and allowing for comparison of nursing home residents' ideas of satisfaction and dissatisfaction to other older patients, including those in an outpatient geriatric setting.

Aged↗
PubMed2000

The relationship between change in blood pressure, blood pressure and time.

Physiological homeostatic mechanisms and interventions by anaesthetists attempt to moderate excessive change in many biological variables during anaesthesia. These mechanisms may have fast or slow response times. This study describes how mean arterial blood pressure changes with time and how the change is dependent upon the pre-existing blood pressure. The results demonstrate the 'regression towards the mean' concept; low arterial blood pressures increase and high pressures decrease. The data are the result of all interactions and have been used to produce an 'envelope' into which 80% of all changes fall. Alarm systems using this envelope could warn of excessive changes that occur within short time intervals.

Adult↗
PubMed2000

Temporary middle cerebral artery occlusion in the rat: consistent protocol for a model of stroke and reperfusion.

The intraluminal suture method of middle cerebral artery occlusion (MCAO) in the rat (the suture model) is a model of stroke which readily lends itself to studying the pathophysiology of post-ischaemic reperfusion. Unfortunately, variability of outcome has compromised the potential of the model, but systematic studies might characterize a consistent protocol. Therefore, the clinical and neuropathological outcome of temporary MCAO and reperfusion in the suture model were systematically investigated. Two hours or 4 h of MCAO were employed, measuring the extent of infarction at 24 h with triphenyltetrazolium chloride or at 72 h with histopathological techniques. Outcome was compared in three rat strains. Following 2 h of MCAO, motor function improved during reperfusion in Sprague-Dawley, but not in Wistar or Fischer-344 rats. All Sprague-Dawley and Wistar rats survived the protocol to 72 h, but 33% of Fischer-344 rats died. The extents of infarction and oedema were greater and less variable in Wistar and Fischer-344 than Sprague-Dawley rats, and in all three strains, the extent of infarction increased with reperfusion time. Following 4 h of MCAO, there was no improvement in motor function during reperfusion in Sprague-Dawley rats, and mortality was high at 24 h in Wistar (33%) and Fischer-344 rats (83%). Outcome was only pursued in Sprague-Dawley rats to 72 h, where the extent of infarction was quite variable. It was concluded that the extent and variability of outcome following temporary MCAO in the suture model is strain-dependent, and a consistent protocol with zero mortality was found in Wistar rats using 2 h of MCAO and 70 h of reperfusion.

Animals↗
PubMed2000

Transformation of Medicago truncatula via infiltration of seedlings or flowering plants with Agrobacterium.

Two rapid and simple in planta transformation methods have been developed for the model legume Medicago truncatula. The first approach is based on a method developed for transformation of Arabidopsis thaliana and involves infiltration of flowering plants with a suspension of Agrobacterium. The second method involves infiltration of young seedlings with Agrobacterium. In both cases a proportion of the progeny of the infiltrated plants is transformed. The transformation frequency ranges from 4.7 to 76% for the flower infiltration method, and from 2.9 to 27.6% for the seedling infiltration method. Both procedures resulted in a mixture of independent transformants and sibling transformants. The transformants were genetically stable, and analysis of the T2 generation indicates that the transgenes are inherited in a Mendelian fashion. These transformation systems will increase the utility of M. truncatula as a model system and enable large-scale insertional mutagenesis. T-DNA tagging and the many adaptations of this approach provide a wide range of opportunities for the analysis of the unique aspects of legumes.

Blotting, Southern↗
PubMed2000

Activation tagging in Arabidopsis.

Activation tagging using T-DNA vectors that contain multimerized transcriptional enhancers from the cauliflower mosaic virus (CaMV) 35S gene has been applied to Arabidopsis plants. New activation-tagging vectors that confer resistance to the antibiotic kanamycin or the herbicide glufosinate have been used to generate several tens of thousands of transformed plants. From these, over 30 dominant mutants with various phenotypes have been isolated. Analysis of a subset of mutants has shown that overexpressed genes are almost always found immediately adjacent to the inserted CaMV 35S enhancers, at distances ranging from 380 bp to 3.6 kb. In at least one case, the CaMV 35S enhancers led primarily to an enhancement of the endogenous expression pattern rather than to constitutive ectopic expression, suggesting that the CaMV 35S enhancers used here act differently than the complete CaMV 35S promoter. This has important implications for the spectrum of genes that will be discovered by this method.

Arabidopsis↗
PubMed2000

Cerebral microembolism detected by transcranial Doppler during cardiac procedures.

BACKGROUND AND PURPOSE: Cerebral embolism with clinical sequelae may rarely complicate cardioversion and cardiac catheterization. Transcranial Doppler sonography has recently been introduced to monitor microemboli entering the middle cerebral artery in cardiac and carotid surgery. We therefore used this technique to evaluate the risk of asymptomatic embolism during common cardiac procedures. METHODS: Patients were monitored by transcranial Doppler while undergoing direct current cardioversion (n=15) and cardiac catheterization (n=17). RESULTS: Microemboli were detected in all patients having cardiac catheterization but in only 1 patient after cardioversion. CONCLUSIONS: Microembolism occurred frequently during cardiac catheterization and rarely during cardioversion. It is not yet known whether this has clinical relevance.

Cardiac Catheterization↗
PubMed2000

Trend recognition in clinical signals using template-based methods.

The recognition of clinically significant trends in monitored signals plays an important role in many medical diagnostic applications. A template-based system technique to identify characteristic patterns in time-series data is described, based on fuzzy logic. Fuzzy set theory allows the creation of fuzzy templates from linguistic rules. The resulting fuzzy template system can accommodate multiple time signals, relative or absolute trends, and automatically generates a normalised "goodness of fit" score. The template approach was originally developed for monitoring during anaesthesia but has the potential to be useful in other domains that require temporal pattern recognition.

Artificial Intelligence↗
PubMed2000

A review of the research on the health of low-income Canadian women.

Reducing health inequities associated with poverty is an important public health nursing role. This article describes the scope of research on the health of low-income Canadian women. The research included was published in English-language peer-reviewed journals between 1990 and 1997. The 26 articles retrieved are summarized according to the focus of the study and the composition of the sample. Most addressed personal health practices and health status. Only one intervention study was identified. The studies and the findings of this analysis are discussed in relation to three recommendations for research on women's health: an emphasis on social context, including the structural conditions affecting women's health; active participation of women in the research process; and recognition of diversity among low-income women. Suggested priority areas for future research are: intervention studies; studies addressing the structural context of the lives of low-income women; research strategies that enhance the participation of women in the research process; and increased involvement of diverse groups of women such as homeless women and women of varied ethnic backgrounds, including First Nations women.

Canada↗
PubMed1999

Activation tagging of the floral inducer FT.

FLOWERING LOCUS T (FT), which acts in parallel with the meristem-identity gene LEAFY (LFY) to induce flowering of Arabidopsis, was isolated by activation tagging. Like LFY, FT acts partially downstream of CONSTANS (CO), which promotes flowering in response to long days. Unlike many other floral regulators, the deduced sequence of the FT protein does not suggest that it directly controls transcription or transcript processing. Instead, it is similar to the sequence of TERMINAL FLOWER 1 (TFL1), an inhibitor of flowering that also shares sequence similarity with membrane-associated mammalian proteins.

Alleles↗