Biomedical subjects

K Norton

Publications and source records attributed to K Norton.

At least 19 recordsLinked to original sources

PubMed2005

A decrease in the association between the physical activity patterns of Australian parents and their children; 1985-1997.

The present study investigated the interactions between parents' and children's physical activity levels by examining whether or not parents who exercise have children who participate in sport. Of primary interest was an investigation of trends in these interactions over time. Information was collected from 10-13 y old children in 1985 (n = 2463) and then again in 1997-99 (n = 1469), about their sports participation and their perceptions of parents' exercise habits. Boys' participation in at least one sport declined from 87% in 1985 to 76% in 1997/1999 while, among girls, participation fell from 80% to 71%. According to their children's perceptions, mothers exercising regularly fell from 36% to 31% between surveys, while fathers exercising regularly fell from 39% to 32%. Interactions between parents' and children's exercise and sports behaviours were examined employing chi-square analysis techniques. Results showed gender-specific relationships for the 1985 sample, such that active fathers were associated with increased participation in sports by boys, and inactive mothers were associated with less participation in sports by girls. These interactions seemed to diminish over time. It is possible that changes in social structures during this time may be affecting familial behaviour relationships, such as the role modelling of active behaviours.

Adolescent↗

PubMed2005

Evidence for secular trends in children's physical activity behaviour.

It is not clear whether the global increase in weight problems in children is the result of excessive energy intake or decreasing energy expenditure. Methodological limitations have made it difficult to analyse. There is evidence that at least part of the problem may lie with increasing energy consumption, but it is important to examine the other side of the energy equation also. However, it is not possible to conclusively describe physical activity trends because of the absence of suitable baseline data. One solution is to summate all available evidence in as many areas of daily activities as possible and then draw tentative conclusions. This review summarises available trend data on direct representations of physical activity in a range of contexts, together with indirect measures such as sedentariness, fitness, and attitudes. The conclusions drawn are: physical activity in clearly defined contexts such as active transport, school physical education, and organised sports is declining in many countries; young people would like to be active but are often constrained by external factors such as school policy or curricula, parental rules in relation to safety and convenience, and physical environmental factors.

Activities of Daily Living↗

PubMed2005

A comparison of patients relapsing to addictive drug use with non-relapsing patients following residential addiction treatment in Antigua.

The outcome of a 29-day residential addiction treatment programme for persons from Antigua and Barbuda with addiction to drugs or alcohol was assessed. All 100 patients entering the drug and alcohol treatment programme at Crossroads Centre Antigua between November 1998 and October 2002 were included. All patients were assessed with regards to drug or alcohol use or abstinence in November 2002 using telephone and mail follow-up as well as informal follow-up with families and other community contacts. Crossroads Centre Antigua is a 35 bed, 29-day residential treatment centre for drug and alcohol addiction serving patients from developed countries (85%) and from the Caribbean region (15%). Patients records were also reviewed to obtain age, gender, ethnicity, drug of choice, years of problematic use, completion of the 29 day programme, family member participation at Crossroads Centre Antigua (a four-day programme) and acceptance of halfway house placement. Of the 100 Antiguan patients admitted, 46 (46%) were abstinent (non-relapsers) at average 20.7+/-14.7 months after treatment. Abstinence did not have to be continuous. Forty-nine were known to be using drug or alcohol (49%) and five (5%) were lost to follow-up and considered to be using drugs (relapsers). Age (37.5 vs 41.1 years), gender (28% vs 22% female), ethnicity (87% vs 87% Afro-Caribbean), years of harmful use (12.7 vs 12.5 years) did not differ significantly between relapsers and non-relapsers. Crack cocaine use (67% vs 65%) and alcohol use (26% vs 31%) as primary addiction did not differ significantly between relapsers and non-relapsers. Relapsers were significantly less likely to complete the 29- day programme (81% vs 100%, p < 0.01), have family members participate at Crossroads (32% vs 54%, p < 0.05) or accept halfway house placement (4% vs 54%, p < 0.001). In conclusion, abstinence was achieved in 46% of those entering treatment, in 51% completing treatment, in 60% whose families participated and in 92% of those accepting halfway house placement.

Adult↗

PubMed2004

Client-centred assessment and the identification of meaningful treatment goals for individuals with a spinal cord injury.

STUDY DESIGN: Retrospective analysis. OBJECTIVES: (1) Describe the self-care, productivity and leisure problems identified by individuals with a spinal cord injury (SCI) during rehabilitation, (2) describe the perceived level of satisfaction and performance with self-care, productivity and leisure activities following an SCI, (3) quantify the relationship between the Canadian occupational performance measure (COPM), a client-centred, individualized measure of function, and the functional independence measure (FIM). SETTING: Tertiary rehabilitation centre, spinal cord injury unit, GF Strong Rehabilitation Centre, Vancouver, Canada. METHODS: Health records from 41 individuals with an SCI admitted between 2000 and 2002 were reviewed. Information was obtained from assessments performed on admission and discharge. Self-care, productivity and leisure problems identified by individuals with an SCI were described and their perceived level of performance and satisfaction was calculated. The relationship between the COPM and the FIM was measured by the Pearson product correlation. RESULTS: Self-care goals were identified most frequently (79%) followed by productivity (12%) and leisure (9%) goals. The top three problems identified by individuals with an SCI were functional mobility (including transfers and wheelchair use), dressing and grooming. A fair relationship was found between the COPM and the FIM (r between 0.351 and 0.514, P<0.05). CONCLUSIONS: The results highlight the importance of including a client-centred outcome measure in the assessment of individuals with an SCI. Initial support is provided for use of the COPM in individuals with an SCI.

Activities of Daily Living↗

PubMed2001

Analysis of the physicochemical interactions between Clostridium difficile toxins and cholestyramine using liquid chromatography with post-column derivatization.

A potential therapy for antibiotic-associated pseudomembranous colitis is to bind Clostridium difficile toxins A and B using cholestyramine, a hydrophobic anion exchange medium. Frontal analysis in isotonic phosphate buffer was studied using post-column derivatization with o-phthalaldehyde, which gave a highly sensitive (> or =30 ng) flow-through analysis. Following load (1.5-3.0 microg toxin/3.6 mg), toxin A was bound at a slightly higher capacity than B, due to slower kinetics. A salt gradient eluted roughly 20% of bound toxin A with 0.6 M NaCl and toxin B with 1.1 M NaCl, hence toxin A showed weaker electrostatic affinity. The remainder of toxin A (65%) and some of toxin B (10% out of 50%) were eluted using a subsequent gradient to 60% acetonitrile in normal saline, which measured predominantly hydrophobic binding. Low and high affinity populations of both toxins were observed. Glycocholic acid or amino acids were competitive binders, although these components had little effect on the toxin A population bound primarily through ionic interactions. Competitive protein constituents in hamster cecal contents were also profiled. These results help to explain the variable clinical response in using cholestyramine to treat colitis. Using quaternary amine-polyhydroxymethacrylate (PHM) ion exchange chromatography, a trend for increased binding at higher pH was observed, especially for toxin A. Binding to strong cation exchange resins (sulfonate-PHM) was not observed. A range of reversed phase media retained both toxins, although recovery was very poor relative to protein standards. Size exclusion chromatography with light scattering detection showed that toxin B exists in different aggregation states, while toxin A remains monomeric.

Animals↗

PubMed2001

A phase 1/2 clinical trial of enzyme replacement in fabry disease: pharmacokinetic, substrate clearance, and safety studies.

Fabry disease results from deficient alpha-galactosidase A (alpha-Gal A) activity and the pathologic accumulation of the globotriaosylceramide (GL-3) and related glycosphingolipids, primarily in vascular endothelial lysosomes. Treatment is currently palliative, and affected patients generally die in their 40s or 50s. Preclinical studies of recombinant human alpha-Gal A (r-halphaGalA) infusions in knockout mice demonstrated reduction of GL-3 in tissues and plasma, providing rationale for a phase 1/2 clinical trial. Here, we report a single-center, open-label, dose-ranging study of r-halphaGalA treatment in 15 patients, each of whom received five infusions at one of five dose regimens. Intravenously administered r-halphaGalA was cleared from the circulation in a dose-dependent manner, via both saturable and non-saturable pathways. Rapid and marked reductions in plasma and tissue GL-3 were observed biochemically, histologically, and/or ultrastructurally. Clearance of plasma GL-3 was dose-dependent. In patients with pre- and posttreatment biopsies, mean GL-3 content decreased 84% in liver (n=13), was markedly reduced in kidney in four of five patients, and after five doses was modestly lowered in the endomyocardium of four of seven patients. GL-3 deposits were cleared to near normal or were markedly reduced in the vascular endothelium of liver, skin, heart, and kidney, on the basis of light- and electron-microscopic evaluation. In addition, patients reported less pain, increased ability to sweat, and improved quality-of-life measures. Infusions were well tolerated; four patients experienced mild-to-moderate reactions, suggestive of hypersensitivity, that were managed conservatively. Of 15 patients, 8 (53%) developed IgG antibodies to r-halphaGalA; however, the antibodies were not neutralizing, as indicated by unchanged pharmacokinetic values for infusions 1 and 5. This study provides the basis for a phase 3 trial of enzyme-replacement therapy for Fabry disease.

Adolescent↗

PubMed2001

Evidence for the aetiology of injuries in Australian football.

OBJECTIVES: To determine in Australian football (a) the influence of ground hardness and playing grade (level) on game speed and structure, and (b) player movement patterns throughout the game and across levels. METHODS: The design consisted of several studies. Seventeen games played on grounds of different hardness in 2000 were used to determine game speed and structure. Four first grade and four second grade grand final games (1994, 1996, 1997, 1999) were used to determine the game speed and structure on the same ground but at different levels. Fifty one players (44 first grade and seven second grade) were used to measure movement patterns within games and across levels during the 2000 season. RESULTS: There was a significant relation between ground hardness and game speed, which could lead to higher injury rates when the ground is harder. There was a 6.7% difference in game speed between the first and second grade levels reflecting differences in injury incidence. The first grade games were also characterised by a greater number of shorter, high intensity play periods and longer stop periods than the second grade games. Midfield players in the first grade games covered about 24% greater distance than their second grade counterparts, and there was a significant difference in their playing speeds. CONCLUSIONS: Over the past 40 years, the game speed in the top level of Australian football has approximately doubled. Over the same time, the number of collisions and the estimated injury incidence have also doubled. This study provides additional support to the suggestion that these variables are strongly linked. Factors such as ground hardness, playing level, and time during the game influence game speed and are therefore important in injury development in Australian football.

Athletic Injuries↗

PubMed2001

Morphological evolution of athletes over the 20th century: causes and consequences.

Over the course of the past century it has become increasingly difficult to find athletes of the size and shape required to compete successfully at the highest level. Sport is Darwinian in that only the 'fittest' reach the highest level of participation. Not every physical characteristic could be expected to play a role in this selection process, but two that are important and for which substantial data assemblies exist, are height and mass. Measurements of elite athlete sizes were obtained from a variety of sources as far back as records allowed. We charted the shift in these anthropometric characteristics of elite sportspeople over time, against a backdrop of secular changes in the general population. Athletes in many sports have been getting taller and more massive over time; the rates of rise outstripping those of the secular trend. In open-ended sports, more massive players have an advantage. Larger players average longer careers and obtain greater financial rewards. In some sports it is equally difficult to find athletes small enough to compete. In contrast, there are sports that demand a narrow range of morphological characteristics. In these sports the size of the most successful athletes over the century has remained constant, despite the drift in the population characteristics from which they are drawn. A number of social factors both drive and are driven by the search for athletes of increasingly rare morphology. These include globalisation and international recruitment, greater financial and social incentives, and the use of special training methods and artificial growth stimuli. In many sports the demand for a specific range in body size reinforces the need to adopt questionable and illegal behaviours to reach the required size and shape to compete at the top level. Future scenarios also include 'gene-farming' through assortative mating and athlete gamete banks.

Biological Evolution↗

PubMed2000

The 'price' of Olympic Gold.

In 1981 the Commonwealth Government established the Australian Institute of Sport (AIS). The Australian Sports Commission (ASC) which administers the AIS has 2 objectives: (1) excellence in sports performances; and (2) increased participation in sports and sports activities. State-based institutes of sport have also been established with the same or very similar objectives. Federal policy directs the bulk of the ASC budget to elite athlete programs. A smaller proportion goes towards community participation. The official reason is based on the notion of the 'trickle-down' or 'demonstration' effect. That is, a flow-on of benefits to the broader community in the form of increased participation as a direct result of elite sports success. The aims of this study were to determine the (1) spending pattern to elite sports programs for the 5 Olympics 1976/77 to 1995/96, (2) evidence for the two ASC objectives having been met, and (3) expected medal tally at the 2000 Olympic Games. Results show funding (in 1998 dollars), has accelerated from about $1.2 million (1976/77) to $106 million in (1997/98), particularly since the Games were awarded to Sydney. The total amount spent on elite athletes was $0.918 billion. In the period 1980-96 Australia won 25 gold and 115 total Olympic medals. This equates to approximately $37 million per gold and $8 million per medal in general. There was a significant linear relationship between money spent and total medals won. This was also found when all medal types were analysed independently. The predicted medal tally in 2000 (based on the cost per medal and the expenditure towards Sydney) indicates the medal count will be about 14+/-1 gold, 15+/-2 silver and 33+/-4 bronze. Based on our nation's record of international sporting achievement, there is little doubt we have fulfilled the ASC's first objective. Current data on physical activity patterns of Australians suggest the second objective has not been met. Focusing attention on and achieving the first objective does not appear to have any bearing on the second objective. It is time to revisit the notion that elite sporting success leads to greater mass participation as a result of the so-called 'trickle-down' effect.

Australia↗

PubMed1999

Determination of amino acids in diverse polymeric matrices using HPLC, with emphasis on agars and agaroses.

Determination of amino acids in polymers with varying structure and charge was performed using vapor phase acid hydrolysis and subsequent precolumn derivatization with 6-aminoquinolyl-N-hydroxysuccinimidyl carbamate (AQC). Percent load of neutral, cationic and anionic peptide-modified synthetic polymers was accurately determined using this technique. Assay utility was shown for glycosaminoglycans and other sulfated polymers, neutral carbohydrate polymers such as agar, agarose, and cellulose, and polymers such as lipopolysaccharide and deoxyribonucleic acid. The carboxylated and sulfated molecules included chondroitin sulfate, hyaluronic acid, dermatan sulfate, and heparin, and the sulfated polymers included fucoidan, carrageenan, and dextran sulfate, as examples. Assayed cumulative amino acid concentrations (i.e. protein levels) are reported, although amino acid distribution data was also available from the analysis. Recovery was acceptable for the various compounds tested and did not correlate with structure. However, different sample sizes were necessary to achieve acceptable recovery, depending on the level of protein present in the matrix. While some matrices contained peaks in addition to the amino acids and amino sugars, they were not found to interfere using the standard gradient separation. Assayed amino acid profiles were compared for agaroses with differing electroendosmosis values and for agar samples from different parts of the globe. While the amounts of protein varied depending on source, the relative distribution of amino acids was very similar across the agar samples surveyed.

Agar↗

PubMed1998

Applying the Sports Medicine Australia pre-exercise screening procedures: who will be excluded?

Recently Sports Medicine Australia (SMA) and the Australian Association for Exercise and Sport Science (AAESS) developed guidelines for pre-exercise screening and supervision of fitness testing, based on the American College of Sports Medicine (ACSM) system. The procedure involves classifying individuals into one of three risk groups (apparently healthy, at higher risk, with known disease). Using data collected in a 1992 survey of 2298 Australian adults aged 18-78 years conducted by the Department of the Arts, Sport, the Environment and Territories (DASET), we calculated the percentage of the general population falling within each risk group and therefore exclusion rates (ie the proportion of subjects who, it is recommended, would require medical clearance prior to exercise or exercise testing). The analysis of data found that between 43-73% of males and 44-61% of females would require clearance. A cost analysis suggests that a rigorous application of the SMA-AAESS guidelines would cost between $250 million and $1.2 billion each year. On the basis of the results, suggestions for reviewing the guidelines have been proposed.

Adult↗

PubMed1997

Change in borderline symptoms one year after therapeutic community treatment for severe personality disorder.

BACKGROUND: The view that severe personality disorder (SPD) is untreatable derives from poor-quality studies of treatment outcome which use indirect measures of SPD pathology. This study evaluates the impact of psychotherapeutic in-patient treatment on core personality disorder symptoms. METHOD: 137 SPD patients completed the Borderline Syndrome Index (BSI) on referral and one year post-treatment ('admitted', n = 70) or one year post-referral ('non-admitted', n = 67); 22 of the non-admitted group were refused extra-contractual referral funding for their treatment. RESULTS: There was a significantly greater reduction in BSI scores in the treated than in the non-admitted group. Changes in BSI scores were significantly positively correlated with length of treatment. Assessment of the reliability and clinical significance of changes in individual subjects showed that the magnitude of this change was reliable and clinically significant in 42.9% of the admitted sample, compared with only 17.9% of the non-admitted sample (18.2% of the unfunded group). CONCLUSIONS: Specialist in-patient treatment is effective in reducing core SPD psychopathology.

Borderline Personality Disorder↗

PubMed1996

Severe personality disorders. Treatment issues and selection for in-patient psychotherapy.

BACKGROUND: Severe personality disorder (SPD) is an imprecise but useful term referring to some notoriously difficult to treat psychiatric patients. Their long-term psychiatric treatment is often unsuccessful, in spite of hospitalisation. The specialist expertise of in-patient psychotherapy units (IPUs) can successfully meet some of SPD patients' needs. METHOD: Relevant literature on the subject is summarised and integrated with the authors' specialist clinical experience. RESULTS: Many clinical problems with SPD patients are interpersonal and prevent any effective therapeutic alliance, which is necessary for successful treatment. With in-patients, inconsistencies in treatment delivery and issues surrounding compulsory treatment reinforce patients' mistrust of professionals, compromising accurate diagnosis and an assessment of the need for specialist IPU referral. CONCLUSIONS: General psychiatric teams are well-placed to plan long-term treatment for SPD patients which may include IPU treatment. Timely referral of selected SPD patients to an IPU maximises a successful outcome, especially if there is appropriate post-discharge collaboration with general psychiatric teams to consolidate gains made.

Combined Modality Therapy↗

PubMed1995

Resolution of a proximal humeral defect in type-1 Gaucher disease by enzyme replacement therapy.

Although rarely they are a normal variant in children, significant defects in the medial aspect of the proximal humeral metaphysis occur in patients with Gaucher disease due to cortical infiltration and erosion of the periosteum by Gaucher cells. Such changes may lead to pathological fractures in Gaucher patients. These crescentic erosions resolved in a 19-year-old patient with type-1 Gaucher disease following enzyme replacement therapy.

Adult↗

PubMed1995

Multiple axis-II diagnoses of personality disorder.

BACKGROUND: Simultaneous diagnosis of more than one personality disorder (PD) has been termed 'comorbidity' or 'co-occurrence' implying that single diagnoses are the norm and multiple diagnoses interesting exceptions. Surveys of PD subjects in fact show 1.5-5.6 diagnoses per subject. Our study explores the hypothesis that multiple PD diagnosis is common and increases with increasingly personality disordered populations. METHOD: The PDQ-R questionnaire was administered to three UK samples: referrals for specialist PD in-patient treatment (n = 275); high tariff offenders attending a probation centre (n = 57); and undergraduate students (n = 274). RESULTS: Means of 6.0 (95% CI 5.7-6.3), 4.0 (3.1-5.0) and 3.4 (3.0-3.8) PDQ-R diagnoses per subject were found respectively. High rates of PD diagnosis in individual subjects suggest that multiple diagnosis is the norm rather than the exception. CONCLUSIONS: Multiple diagnosis of PD is better construed as 'breadth' of psychopathology rather than comorbidity and is a function of sampling frame. High rates of multiple diagnoses question the interpretation of studies of any single PD. The graded construct of 'breadth' of axis-II pathology may further our understanding of PD.

Adolescent↗

PubMed1995

The limits of the possible: models of power supply and demand in cycling.

This paper outlines a general strategy for mathematical modeling of cycling performance. This strategy involves formulating one expression describing the power available for external work from physiological sources. The variables used in this expression include maximal aerobic power (VO2max), fractional utilisation of VO2max, mechanical efficiency, maximal accumulated oxygen deficit, and the time constants relating to the expression of aerobic and anaerobic capacities. A second expression describing the power demand of cycling is then constructed. The variables used in this expression include the mass, projected frontal area and drag characteristics of the system, the coefficient of rolling resistance, environmental variables such as temperature, barometric pressure, relative humidity, wind speed and direction and the slope of the course. The two expressions are equated and solved using an iterative procedure. Two series of trials were used to assess the predictive accuracy of the model, one using track endurance performances and the other a 26 km road time-trial. The correlations between actual and predicted times have been excellent (0.92-0.95, p < or = 0.0001), with small mean differences (0-1.83% of mean performance time) and mean absolute differences (1.07-3.24%). The model allows us to make predictions about the effect of equipment changes and environmental factors, to compare performances under very different conditions, and to predict the limits of the possible in cycling performance. A range of options designed to improve cycling performance is described.

Bicycling↗

PubMed1994

Evaluation and management of congenital cervical teratoma. Case report and review.

Congenital cervical teratoma can be clinically dramatic, although essentially benign. Prognosis is good provided that the airway is quickly stabilized and resection is not delayed. We present a case of massive cervical teratoma diagnosed using antenatal magnetic resonance imaging. The child was maintained on maternal circulation after cesarean section until successfully intubated, with a second team ready for emergent bronchoscopy or tracheotomy. After delivery, the lesion grew rapidly with persistent bleeding; biopsy revealed a benign, immature teratoma. On computed tomography all anatomy ventral to the vertebrae was obliterated. At surgery, however, the tumor was easily resected. The literature is reviewed, with attention to malignancy in neonatal cervical teratoma. Surgery was delayed because of the aggressive imaging appearance and rapid growth. This case suggests that when evaluating neonatal tumors, the standard criteria for infiltration and resectability may require modification.

Adult↗

PubMed1994

Outcome of outpatient psychotherapy in a random allocation treatment study of anorexia nervosa.

Ninety subjects with DSM-III-R anorexia nervosa were randomly allocated to four treatment options, one inpatient, two outpatient, and one comprising an assessment interview only. Twenty were thus offered a package of outpatient individual and family psychotherapy. At 2-year follow-up, 12 of the 20 were classed as well, or very nearly well, according to operationally defined criteria. Statistically significant improvements over time were obtained for weight, mean body mass index (BMI), and also for psychological, sexual, and socioeconomic adjustments. Weight and BMI changes were significantly better than for the assessment only group, some of whom had received extensive treatment elsewhere. The style of the outpatient therapy and compliance with it are described in some detail and prognostic indicators for the treated and untreated groups presented. Lower weights at presentation and vomiting were associated with poorer outcome, although age and length of history were not.

Adaptation, Psychological↗