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Biomedical subjects

G Harris

Publications and source records attributed to G Harris.

At least 19 recordsLinked to original sources
PubMed2006

Core beliefs, recalled parental rearing and eating psychopathology across different age groups.

This study explored and compared the patterns of core beliefs, recalled parental rearing behaviours and eating psychopathology in non-clinical females of different ages; university staff and university students. No differences were found between the two age groups except that younger women had higher Drive for Thinness scores. However, core beliefs were associated with eating attitudes and behaviours in younger women and with recalled parental rearing behaviours in older women. The results suggest that younger women tend to externalise their negative core beliefs in the form of disordered eating behaviour whereas older women appear to express their dysfunctional core beliefs in ways other than weight and shape-related issues. The possible mechanisms behind these findings require further investigation.

Adult↗
PubMed2005

The discovery of moriniafungin, a novel sordarin derivative produced by Morinia pestalozzioides.

A novel sordarin derivative, moriniafungin (1), containing a 2-hydroxysebacic acid residue linked to C-3' of the sordarose residue of sordarin through a 1,3-dioxolan-4-one ring was isolated from the fungus Morinia pestalozzioides. Isolation of moriniafungin employed a highly specific bioassay consisting of a panel of Saccharomyces cerevisiae strains containing chimeric eEF2 for Candida glabrata, Candida krusei, Candida lusitaniae, Crytpococcus neoformans, and Aspergillus fumigatus as well as wild type and human eEF2. Moriniafungin exhibited an MIC of 6 microg/mL versus Candida albicans and IC(50)'s ranging from 0.9 to 70 microg/mL against a panel of clinically relevant Candida strains. Moriniafungin was shown to inhibit in vitro translation in the chimeric S. cerevisae strains at levels consistent with the observed IC(50). Moriniafungin has the broadest antifungal spectrum and most potent activity of any natural sordarin analog identified to date.

Antifungal Agents↗
PubMed2005

Parental rearing behaviours and eating disorders: the moderating role of core beliefs.

OBJECTIVE: Core beliefs have been shown to mediate between eating psychopathology and dysfunctional parent-daughter interactions. However, the possible moderating role of core beliefs has been neglected. This study aimed to explore the hypothesis that core beliefs serve as moderator variables in the relationship between recalled parental rearing behaviours and eating psychopathology. METHOD: Sixty-six women with a current eating disorder completed self-report measures of parental rearing behaviours, core beliefs, and eating psychopathology. RESULTS: Three core beliefs were found to moderate the relationship between paternal rejection and aspects of eating psychopathology. The predictive validity of paternal rejection on aspects of eating symptomatology was found to decrease as dysfunctional core beliefs increased. DISCUSSION: When levels of social isolation, vulnerability to harm, and self-sacrifice core beliefs were high, recalled parental relationships were no longer relevant to current eating psychopathology. The findings provide further evidence that core beliefs are important factors in eating disorder psychopathology and may be clinically useful in identifying targets for treatment.

Adolescent↗
PubMed2004

The relationship between parental eating problems and children's feeding behavior: a selective review of the literature.

This review describes the research evidence linking parental eating problems with processes that affect children's food selection and rejection, including child feeding difficulties, and child dieting practices and attitudes. First, studies that assess the relationship between parental eating disorder and child feeding are reviewed. Secondly, research that examines the relationship between parent and child dieting behavior and attitudes is reviewed. Finally, the eating characteristics of parents whose children have feeding difficulties are discussed. There is no consensus in the literature about the relationships between parent and child feeding and eating disturbance, and mechanisms for the intergenerational transmission of these behaviors have yet to be established.

Adult↗
PubMed2004

Assessment of bone formation in a porcine mandibular distraction wound by computed tomography.

The purpose of this study was to document the progression of bone formation in a porcine mandibular distraction wound, at various distraction rates and fixation times, using three-dimensional computed tomography. Bone formation was assessed in a 0-day latency model (n=24 minipigs) using distraction rates of 1, 2, or 4 mm/day to create a 12 mm distraction gap. Animals were sacrificed at 0, 8, 16, or 24 days fixation. For experimental and control sides, three-dimensional data from computed tomographic scans were used to calculate the percent bone volume in the regions of interest. Standardized plain radiographs were used to evaluate bone formation with a semiquantitative scale: 0, 1, 2, 3. Mean percent bone volume and radiographic bone fill scores (pooled sample) increased with fixation time from 16.8% and 0.17 at 0 days, to 64% and 2.0 at 24 days fixation. Mandibles distracted at 1mm/day had higher CT values and bone fill scores than mandibles distracted at 2 or 4 mm/day. At 24 days fixation, the maximum percent bone volume (64%--1 mm/day; 24 days fixation) remained below control values (81.3%). The results of this study indicate that despite high bone fill scores on plain radiographs, the highest percent CT bone volume achieved in this model was 64%.

Animals↗
PubMed2003

Occupational health issues affecting the pharmaceutical sales force.

BACKGROUND: The sales force forms a significant sub-population in the pharmaceutical industry workforce. Role and organizational characteristics, such as isolation, peripatetic working and car travel and the psychosocial and ergonomic hazards related to work tasks, present particular occupational health risks. AIM: To review the occupational risks associated with peripatetic sales force work and evidence for the effectiveness of preventive interventions. METHODS: We carried out a review of the available literature between 1990 and 2003. RESULTS: The following hazards were identified as significant and worthy of further investigation for this occupational group: driving on company business; violence in the workplace; stress; ergonomic issues; and mobile phone use. CONCLUSION: To ensure effective prevention and management of employee health problems, specific health management strategies and interventions must be developed to meet the occupational health needs of this group.

Accidents, Traffic↗
PubMed2002

Bias-induced forces in conducting atomic force microscopy and contact charging of organic monolayers.

Contact electrification, a surface property of bulk dielectric materials, has now been observed at the molecular scale using conducting atomic force microscopy (AFM). Conducting AFM measures the electrical properties of an organic film sandwiched between a conducting probe and a conducting substrate. This paper describes physical changes in the film caused by the application of a bias. Contact of the probe leads to direct mechanical stress and the applied electric field results in both Maxwell stresses and electrostriction. Additional forces arise from charge injection (contact charging). Electrostriction and contact charging act oppositely from the normal long-range Coulomb attraction and dominate when a charged tip touches an insulating film, causing the tip to deflect away from the film at high bias. A bias-induced repulsion observed in spin-coated PMMA films may be accounted for by either mechanism. In self-assembled monolayers, however, tunnel current signals show that the repulsion is dominated by contact charging.

Journal Article↗
PubMed2002

A behavioural intervention in a child with feeding problems.

AIM: This case study aimed to describe an intervention with a 2-year-old child with growth problems and moderately severe feeding difficulties. METHOD: The intervention was based on cognitive behavioural principles and psycho-physiological techniques, and focused on reducing parental anxiety and returning the control of feeding to the child. RESULTS: The child's feeding behaviour considerably improved over a 6-month period, and growth and weight were significantly increased. These positive changes have been maintained for a 3-year subsequent period. CONCLUSION: The principles described can be applied to children with a wide range of feeding problems with multivariate causes.

Anxiety↗
PubMed2002

Acute renal failure following ingestion of wild mushrooms.

We describe three cases of acute renal failure in young men who ingested wild mushrooms with the intent of producing hallucinations. Two cases remained dialysis dependent and, in these cases, renal biopsy revealed tubulointerstitial nephritis and fibrosis. Similar cases have been reported in other countries, but not in Australia. The most recognized mushroom nephrotoxin is orellanine, however the causative mushroom species and the actual toxin involved in these cases are unknown.

2,2'-Dipyridyl↗
PubMed2002

The effect of 6-aminohexanoic acid and fucoidan on the activation of glutamic plasminogen by streptokinase.

Studies were conducted on the effect of 6-aminohexanoic acid (6-AH) or fucoidan on the activation of glutamic plasminogen (glu-plg) by streptokinase using 0.05 mol/l Tris buffer containing a physiological concentration of NaCl. In contrast to the earlier reports where no NaCl was added to the buffer solution, addition of 6-AH enhanced the initial rate while the inhibition by fucoidan was not affected. Double reciprocal plots of the activation of glu-plg by streptokinase in the presence of 6-AH showed an increase in Vmax, but no change in Km. However, the addition of fucoidan showed a decrease in Vmax, but no change in Km. To determine whether the stimulatory effect of 6-AH was specifically directed towards glu-plg or streptokinase, the ratios of the initial rate of plasmin generation in the presence of 6-AH over the controls were plotted against the inverse of the volume fraction of glu-plg or streptokinase after serial dilutions. The results indicated that the dilutions of glu-plg, but not of streptokinase, influenced the ratios, suggesting an interaction of 6-AH with glu-plg. Similar experiments were conducted to determine the mechanism of inhibition of streptokinase by fucoidan. The results indicated that fucoidan was interacting with streptokinase, but not with glu-plg. Circular dichroism studies of glu-plg in the near-ultraviolet spectra (250-308 nm) showed that addition of 6-AH enhanced the spectra in the region around certain chromophores, which reflected conformational changes. On the contrary, the far-ultraviolet spectra were almost identical.

Aminocaproic Acid↗
PubMed2001

Reproducible measurement of single-molecule conductivity.

A reliable method has been developed for making through-bond electrical contacts to molecules. Current-voltage curves are quantized as integer multiples of one fundamental curve, an observation used to identify single-molecule contacts. The resistance of a single octanedithiol molecule was 900 +/- 50 megohms, based on measurements on more than 1000 single molecules. In contrast, nonbonded contacts to octanethiol monolayers were at least four orders of magnitude more resistive, less reproducible, and had a different voltage dependence, demonstrating that the measurement of intrinsic molecular properties requires chemically bonded contacts.

Chemical Phenomena↗
PubMed2001

Protein phosphatase 2A activates the proapoptotic function of BAD in interleukin- 3-dependent lymphoid cells by a mechanism requiring 14-3-3 dissociation.

BAD is a proapoptotic member of the BCL-2 family of proteins, which play a major role in regulating apoptosis in cytokine-dependent hematopoietic cells. The function of BAD is regulated by reversible phosphorylation. Deprivation of survival factors induces BAD dephosphorylation, resulting in apoptosis. Serine-threonine phosphatase activity dephosphorylated BAD in interleukin-3-dependent FL5.12 lymphoid cells. Inhibition of PP2A activity by treatment of cells with PP2A-selective inhibitors, okadaic acid and fostriecin, prevented BAD dephosphorylation in these cells. Conversely, BAD dephosphorylation was not inhibited by the PP1-selective inhibitor tautomycin. In cell-free extracts, BAD phosphatase activity was also inhibited by the PP2A-selective inhibitors okadaic acid and fostriecin, but not by the PP1-specific protein inhibitor I-2. Dissociation of 14-3-3 from BAD was a prerequisite for BAD dephosphorylation in vitro, suggesting a mechanism by which 14-3-3 can regulate the activation of the proapoptotic function of BAD in vivo. Significantly, the inhibition of BAD phosphatase activity rescued cell death induced by survival factor withdrawal in FL5.12 cells expressing wild-type BAD but not phosphorylation-defective mutant BAD. These data indicate that PP2A, or a PP2A-like enzyme, dephosphorylates BAD and, in conjunction with 14-3-3, modulates cytokine-mediated survival.

14-3-3 Proteins↗
PubMed2001

Colorimetric detection of glutamine synthetase-catalyzed transferase activity in glucocorticoid-treated skeletal muscle cells.

Induction of the enzyme glutamine synthetase (GS) by corticosteroids correlates with muscle wasting and gluconeogenesis, characteristic side effects of chronic glucocorticoid treatment. This highlights the importance of developing robust high-throughput assays to measure drug-induced GS in whole cells. We have optimized a colorimetric method to measure GS-catalyzed gamma-glutamyltransferase (GT) activity in rat L6 skeletal muscle cells (96-well-plate format) and human skeletal muscle cells (24-well-plate format). We observe a fourfold increase in GT activity in dexamethasone treated L6 cells, as compared to untreated cells, with good reproducibility in the measurements (errors of less than 5%). This assay can distinguish between partial agonists such as halopredone acetate and complete agonists such as prednisolone and measure the potency of known glucocorticoid receptor (GR) antagonists like mifepristone. Importantly, the ability of corticosteroids to induce GS-catalyzed GT activity correlates well with their whole cell GR binding potency, indicating a GR-specific effect. Interestingly, in general, induction of GT activity by commonly administered anti-inflammatory corticosteroid drugs is comparable in rat and human skeletal muscle cells, which emphasizes the potential of a rat model system to study GS induction and muscle wasting by these drugs in humans.

Animals↗
PubMed2001

Evaluation of uncalibrated preferential flow models against data for isoproturon movement to drains through a heavy clay soil.

The uncalibrated predictive ability of four preferential flow models (CRACK-NP, MACRO/MACRO_DB, PLM, SWAT) has been evaluated against point rates of drainflow and associated concentrations of isoproturon from a highly structured and heterogeneous clay soil in the south of England. Data were available for four plots for a number of storm events in each of three successive growing seasons. The mechanistic models CRACK-NP and MACRO generally gave reasonable estimates of drainflow over the three seasons, but under-estimated concentrations of isoproturon over a prolonged period in the first season and over-estimated them in the two remaining seasons. CRACK-NP simulated maximum concentrations of isoproturon over the first two events of each of the three seasons of 156, 527 and 24.4 micrograms litre-1, respectively, and matched the observed data (465, 65.1 and 0.65 micrograms litre-1) slightly better than MACRO (69.1, 566 and 58.5 micrograms litre-1). Automatic selection of parameters from soils information within MACRO_DB reduced the emphasis on preferential flow relative to the stand-alone version of MACRO. This gave a poor simulation of isoproturon breakthrough and simulated maximum concentrations were 0, 50.1 and 35.1 micrograms litre-1, respectively. The capacity model PLM gave the best overall simulation of total drainflow for the first two events in each season, but over-estimated concentrations of isoproturon (967, 808 and 51.3 micrograms litre-1). The simple model SWAT represented total drainflow reasonably well and gave the best simulation of maximum isoproturon concentrations (140, 80.2 and 8.2 micrograms litre-1). There was no clear advantage here in using the mechanistic models rather than the simpler models. None of the models tested was able to simulate consistently the data set, and uncalibrated modelling cannot be recommended for such artificially drained heavy clay soils.

Aluminum Silicates↗
PubMed2001

A basic approach to the interpretation of the exercise test.

To interpret the exercise test, the following parameters need to be evaluated: the heart rate and blood pressure response, symptoms, dysrhythmias, aerobic capacity, and evidence for myocardial ischemia. When analyzing the ST segment for ischemia, the amount and type of ST depression and the time of onset and resolution are examined. The exercise test results are best used to determine a post-test probability that the patient has significant coronary disease, predict its severity, and provide a prognosis of the patient. The test allows primary care physicians to decide which patients with coronary artery disease can be safely managed medically and which high-risk patients need further evaluation and consideration for revascularization.

Arrhythmias, Cardiac↗
PubMed2001

Potential influence of acute CT on inpatient costs in patients with ischemic stroke.

RATIONALE AND OBJECTIVES: Patients presenting with ischemic brain symptoms have widely variable outcomes dependent to some degree on the pathologic basis of their stroke syndrome. The purpose of this study was to determine the cost implications of the emergency use of a computed tomographic (CT) protocol comprising unenhanced CT, head and neck CT angiography, and whole-brain CT perfusion. MATERIALS AND METHODS: By using a retrospective patient database from a tertiary care facility and publicly available cost data, the authors derived the potential savings from the use of CT angiography. CT perfusion, or both at hospital arrival by means of a cost model. The cost of the CT angiography-CT perfusion protocol was determined from Medicare reimbursement rates and compared with that of traditional imaging protocols. Cost savings were estimated as a decrease in the length of stay for most stroke patients, whereas the most benign (lacunar) strokes were assumed to be managed in a non-acute setting. Misdiagnosis cost (erroneously not admitting a patient with nonlacunar stroke) was calculated as the cost of a severe complication. Sensitivity testing included varying the percentage of misdiagnosed patients and admitting patients with lacunar stroke. RESULTS: The nationwide net savings that would result from the adoption of the CT angiography-CT perfusion protocol are in the $1.2 billion range (-$154 million to $2.1 billion) when patients with lacunar strokes are treated nonacutely and $1.8 billion when those patients are admitted for acute care. CONCLUSION: The results demonstrate the potential effect of implementing a CT angiography-CT perfusion protocol. In particular, prompt CT angiography-CT perfusion imaging could have an effect on the cost of acute care in the treatment of stroke.

Cerebral Angiography↗
PubMed2001

Feeding problems in Silver-Russell syndrome.

In order to identify the prevalence and severity of feeding problems in children with Silver-Russell syndrome (SRS) the feeding difficulties of 32 children with SRS and 32 age- and sex-matched control children were assessed using the Feeding Assessment Questionnaire (Harris and Booth 1992). Children's ages ranged from 2 to 11 years, with 19 male and 13 female pairs. In a subset of matched pairs, parent-child interaction at mealtimes was examined using video recording; food intake was also assessed over a 3-day period using weighed food diaries. Children with SRS experienced significantly more feeding problems than children without growth disorders. Common feeding problems for children with SRS were poor appetite, fussiness, slow feeding, and problems associated with oral-motor dysfunction. Feeding problems did not significantly affect intake of kilocalories, protein, fat, or carbohydrates. Mealtime interaction between children with SRS and their parents was significantly more negative than interactions between control-group children and their parents. The focus of intervention packages in SRS should be to reduce negative parent-child interactions and reduce parental anxiety about feeding, growth, and weight.

Abnormalities, Multiple↗