Biomedical subjects

F J Cameron

Publications and source records attributed to F J Cameron.

At least 19 recordsLinked to original sources

PubMed2006

Interventions to promote optimal health outcomes in children with Type 1 diabetes--are they effective?

The incidence of Type 1 diabetes is increasing worldwide, imposing enormous public health costs, as well as profoundly affecting individual quality of life. There is evidence that psychological problems are increased in children with diabetes and this morbidity is often associated with poor metabolic control. Specific risk factors for this dual morbidity are emerging from empirical studies. The next challenge is to identify effective interventions for use with children at risk for adverse mental and physical health outcomes. The intervention literature is reviewed. It is noted that most studies have used diabetes-specific, unstandardized interventions in groups of adolescents, with few interventions trialled with younger children. No study has targeted a specific psychological disorder such as behaviour problems or depression, both of which are known to be increased in children with diabetes and for which effective standardized interventions are available. Attention is drawn to methodological limitations in many of the studies conducted to date and suggestions made to reduce these in future interventions attempting to reduce the burden of illness in children with diabetes.

Adaptation, Psychological↗

PubMed2006

Social consumption of alcohol in adolescents with Type 1 diabetes is associated with increased glucose lability, but not hypoglycaemia.

AIM: To determine the effects of social consumption of alcohol by diabetic adolescents on glycaemic control. METHODS: Fourteen (five male) patients aged > 16 years were recruited from the diabetes clinic at the Royal Children's Hospital. The continuous glucose monitoring system (CGMS) was attached at a weekend when alcohol consumption was planned for one night only. For each patient, the 12-h period from 18.00 h to 06.00 h for the night with alcohol consumption (study period) was compared with the same period with non-alcohol consumption (control period) either 24 h before or after the alcohol study night. Thus, each subject was his/her own control. Glycaemic outcomes calculated from continuous glucose monitoring included mean blood glucose (MBG), percentage of time spent at low glucose levels (CGMS < 4.0 mmol/l), normal glucose levels (CGMS 4.0-10.0 mmol/l) and high glucose levels (> 10.0 mmol/l) and continuous overall net glycaemic action (CONGA). RESULTS: The mean number of standard alcohol drinks consumed during the study period was 9.0 for males and 6.3 for females. There was no difference in percentage of time at high and normal glucose levels in the study and control periods. During the control period, there was a higher percentage of time with low glucose levels compared with the study period (P < 0.05). There was an increased level of glycaemic variation during the study time when compared with the control period. CONCLUSIONS: In an uncontrolled, social context, moderately heavy alcohol consumption by adolescents with Type 1 diabetes appears to be associated with increased glycaemic variation, but not with low glucose levels.

Adolescent↗

PubMed2005

Age-related pituitary volumes in prepubertal children with normal endocrine function: volumetric magnetic resonance data.

BACKGROUND: Evaluation of the size of the pituitary gland on magnetic resonance imaging (MRI) may be difficult, considering the wide variation in normal gland morphology. Given the paucity of age-related biometric data, our purpose was to obtain standard normal reference values for pituitary volumes in prepubertal children using three-dimensional MRI data. METHODS: Children under the age of 10 yr undergoing brain MRI for seizures or idiopathic developmental delay and who had no endocrine abnormality were recruited prospectively over 2 yr. All MRI studies included a three-dimensional sequence. Only subjects with normal studies were included. One hundred thirty-nine children were eligible (mean age, 5.2 yr). Direct pituitary volumes were measured from contiguous 1-mm thick reconstructed coronal and sagittal images. Estimated pituitary volumes were calculated using pituitary height, width, and length. RESULTS: Volumes obtained from reconstructions in either plane were essentially identical. There was a linear increase in log-transformed pituitary volume with age, but relatively weak correlations with height or body mass index. There was no gender difference and only weak correlations between pituitary height and pituitary volume and between estimated pituitary volume calculation and measured pituitary volume. We provide age-related reference ranges for pituitary volumes in graphical and tabular forms.

Body Height↗

PubMed2005

Association of body composition and lung function in children with cystic fibrosis.

Survival in cystic fibrosis has improved significantly in the last 30 years, with major therapeutic goals of delaying the progressive loss of pulmonary function and maintaining normal growth. Dual-energy X-ray absorptiometry (DEXA) was performed in children with cystic fibrosis (CF) to assess both bone mineral density and body composition. We hypothesised that there would be an association between body composition and pulmonary function in children with CF. Fifty subjects with CF (28 males), mean age 12.7 years, participated in the study. Body composition was determined by DEXA. Body mass index (BMI) was calculated from the ratio of weight/height2 (kg/m2). Lung function was assessed by spirometry. Most patients (78%) had mild lung disease. The mean forced expired volume in 1 sec percent predicted (FEV1% predicted) for the 50 patients was 79.2% (range, 24-117%). There was a strong association between FEV1% predicted and BMI (R=0.59, P=0.0001). Fat-free mass had positive association with pulmonary function tests (R=0.30, P=0.03). Although fat mass showed a positive correlation with pulmonary function, this association did not reach statistical significance. In our group of children with CF and mild lung disease, pulmonary function was more strongly associated with BMI than with fat and fat-free mass.

Absorptiometry, Photon↗

PubMed2005

A novel approach to continuous glucose analysis utilizing glycemic variation.

BACKGROUND: Various methodologies have been proposed for analysis of continuous glucose measurements. These methods have mainly focused on the proportion of low or high glucose readings and have not attempted to analyze other dimensions of the data obtained. This study proposes an algorithm for analysis of continuous glucose data including a novel method of assessing glycemic variability. METHODS: Mean blood glucose and mean of daily differences (MODD) assessed the degree that the Continuous Glucose Monitoring System (CGMS, Medtronic MiniMed, Northridge, CA) trace was representative of the 3-month glycemic pattern. Percentages of times in low, normal, and high glucose ranges were used to assess marked glycemic excursion. Continuous overall net glycemic action (CONGA), a novel method developed by the authors, assessed intra-day glycemic variability. These methods were applied to 10 CGMS traces chosen randomly from those completed by children with type 1 diabetes from the Royal Children's Hospital, Melbourne, Victoria, Australia and 10 traces recorded by healthy volunteer controls. RESULTS: The healthy controls had lower values for mean blood glucose, MODD, and CONGA. Patients with diabetes had higher percentages of time spent in high and low glucose ranges. There was no overlap between the CONGA values for patients with diabetes and for controls, and the difference between controls and patients with diabetes increased markedly as the CONGA time period increased. CONCLUSIONS: We advocate an approach to the analysis of CGMS data based upon a hierarchy of relevant clinical questions alluding to the representative nature of the data, the amount of time spent in glycemic excursions, and the degree of glycemic variation. Integrated use of these algorithms distinguishes between various patterns of glycemic control in those with and without diabetes.

Adolescent↗

PubMed2005

Psychiatric morbidity and health outcome in Type 1 diabetes--perspectives from a prospective longitudinal study.

AIMS: To describe psychiatric status and relationship to metabolic control in adolescents with Type 1 diabetes studied prospectively from diagnosis. METHODS: Adolescents (n = 41) completed a self-report measure of psychiatric status 10 years after disease onset. Metabolic control information was recorded prospectively from diagnosis. The rate and type of psychiatric disorder were determined and the relationship between mental health status and metabolic control history examined. RESULTS: Thirty-seven per cent of the adolescents met criteria for a DSM-IV psychiatric disorder, two to three times higher than community levels of psychiatric morbidity. Females were significantly more likely to receive a diagnoses (chi2 = 4.98, P < 0.05). Two thirds of participants had experienced at least one serious hypoglycaemic episode and one third had a history of chronic poor metabolic control. DSM-IV diagnoses were present in half of those with a history of chronic poor control, one third of the hypoglycaemia group and one quarter of well controlled participants. Adolescents with a current Mood (t = -2.83, P < 0. 01), Anxiety (t = -3.77, P = 0.001) or Behaviour (t = 2.56, P < 0.05) disorder and those with a history of poorly controlled diabetes (F (2,29) = 5.4, P = 0.01) had higher externalizing behaviour problem scores at diagnosis than those without current disorder. CONCLUSIONS: Adolescents with Type 1 diabetes are at high risk for psychiatric disorder. Poorly controlled diabetes over the first 10 years of illness was associated with pre-existing behaviour problems at diagnosis and there was a trend for an association with current psychiatric status.

Adolescent↗

PubMed2005

Insights into the acute cerebral metabolic changes associated with childhood diabetes.

AIMS: Type 1 diabetes is a prevalent chronic disease in childhood with the commonest single cause of death being cerebral oedema in the context of diabetic ketoacidosis (DKA). The nature of the alterations in cerebral metabolism that may result in vulnerability to neuronal injury remains unknown. The aim of this study was to analyse the magnetic resonance imaging (MRI) and magnetic resonance spectroscopy (MRS) brain data from eight children with diabetes following acute presentation with hyperglycaemia with or without ketoacidosis, to determine the nature and timing of any alterations in cerebral structure and metabolism. METHODS: This study used MRI and MRS to investigate regional cerebral abnormalities in a small series of diabetic patients with and without DKA. Changes were compared with the clinical and biochemical features of the patients studied. RESULTS: Our small series of patients all demonstrated abnormal signal changes in the frontal region on fluid attenuated inversion recovery (FLAIR) MR imaging, suggestive of oedema, and spectroscopic abnormalities of increased taurine, myoinositol and glucose levels. The MR abnormalities varied in severity but did not correlate with any clinical or biochemical parameters. CONCLUSIONS: These changes indicate that many diabetic children, particularly at presentation, may have alterations in cerebral metabolism with implications for the pathogenesis and treatment of the cerebral complications of DKA. In addition, our findings suggest that increased taurine may be one of the important differentiating factors in the response of the brain of diabetic children to DKA that may reflect an increase in their vulnerability to cerebral oedema compared with diabetic adults.

Adolescent↗

PubMed2005

Childhood precursors of adolescent outcomes in type 1 diabetes mellitus.

Contemporary outcome measures of chronic illnesses such as type 1 diabetes mellitus are broader than those clinical outcomes traditionally assessed in therapeutic encounters. A holistic approach emphasises quality of life and emotional well-being as well as the achievement of optimal disease management. This paper reviews current knowledge about growth, metabolic control, diabetes complications, neurocognitive and psychological outcomes as well as health-related quality of life in childhood diabetes mellitus. It is suggested that the antecedents of adverse diabetes and psychological outcomes in adolescence lie in the years prior to adolescence. The model of care in childhood diabetes mellitus must be focussed on earlier screening and intervention if adverse outcomes are to be reduced.

Adolescent↗

PubMed2005

Rates of diabetes mellitus-related complications in a contemporary adolescent cohort.

BACKGROUND: Ten years after the Diabetes Control and Complications Trial there is a paucity of data as to what are current rates of diabetes-related complications in adolescence. OBJECTIVE: To assess the incidence of diabetes-related complications in a contemporary cohort of adolescents with type 1 diabetes mellitus. DESIGN: Retrospective cross-sectional survey. PATIENTS: Adolescents aged >10 years with type 1 diabetes mellitus for >5 years from the Royal Children's Hospital, Melbourne Diabetes Clinic. RESULTS: 382 patients were studied (191 male). The mean HbA1c for males was 8.72% and for females was 8.80%. The rates of hypothyroidism and hypercholesterolaemia were 1.5% and 22% respectively. Twenty-five patients (8%) had intermittent microalbuminuria and six (2%) had persistent microalbuminuria. Only one patient had macroalbuminuria (0.3%). Only two patients (0.7%) with mild non-were diagnosed proliferative diabetic retinopathy. Coeliac disease was diagnosed in 6% of patients. CONCLUSIONS: In this representative and contemporary cohort of diabetic adolescents the incidence of microvascular diabetes-related complications is quite low.

Adolescent↗

PubMed2004

Hypoketotic hypofattyacidaemic hypoinsulinaemic hypoglycaemia in a child with hemihypertrophy? A new syndrome.

BACKGROUND: Recurrent and persistent hypoketotic, hypofattyacidaemic hypoglycaemia in infancy and childhood is most frequently due to hyperinsulinism of infancy. This biochemical profile can also be due to non-islet cell tumour hypoglycaemia or circulating insulin-receptor autoantibodies. Hyperinsulinaemic hypoglycaemia is also seen in children with the Beckwith-Wiedemann syndrome, where it is usually transient. METHODS/RESULTS: We report a novel case of child with hemihypertrophy and severe persistent hypoketotic, hypofattyacidaemic hypoinsulinaemic hypoglycaemia. No 'big' pro-IGF2 forms or circulating insulin-receptor antibodies were found. Glucose and protein isotope turnover studies showed marked suppression of hepatic glucose production during fasting. There was no evidence for constitutive autophosphorylation of the insulin or IGF-1 receptor, and no evidence for up-regulation of IGF-1 receptor. CONCLUSION: The precise pathophysiology of this novel case is still unclear.

Abnormalities, Multiple↗

PubMed2004

Antipsychotic medication and marked hyperprolactinaemia: iatros or true prolactinoma?

AIM: To demonstrate that hyperprolactinaemia and/or prolactinoma occur in association with antipsychotic medication use. METHODS: Three case studies of patients with markedly elevated serum prolactin level (>132 microg/l); either antipsychotic medication induced or as a consequence of a prolactinoma. CONCLUSION: The management and investigation of children with markedly elevated serum prolactin levels remains poorly defined. In our case series, two patients were found to have prolactinomas. We suggest that paediatric patients with serum prolactin level above 50 microg/l in males and 70 microg/l in females, regardless of any antipsychotic medication use, receive magnetic resonance imaging to exclude prolactinoma.

Adolescent↗

PubMed2004

Does continuous glucose monitoring have clinical utility in contemporary management of diabetes?

Continuous, automated and non-invasive blood glucose monitoring systems have long been a goal to assist management of diabetes mellitus. The first continuous, albeit invasive, device available in Australia is the Medtronic MiniMed Continuous Glucose Monitoring System (CGMS), which is available for physician-supervised use to give a continuous blood glucose profile (5-minutely readings, viewable only after download by the physician) for periods of 72 h. With the availability of this technology, there is a need to assess the accuracy, reproducibility and ability to detect significant clinical events (particularly hypoglycaemia) and blood glucose patterns. The question of whether this technique allows long-term improvement of metabolic control also arises. We present four case studies to illustrate the use of CGMS in clinical practice and have reviewed the rapidly emerging literature. We conclude that CGMS is a useful clinical tool in the management of diabetes mellitus, provided that it is appropriately applied and the limitations are understood.

Adolescent↗

PubMed2003

Early detection of emotional and behavioural problems in children with diabetes: the validity of the Child Health Questionnaire as a screening instrument.

AIMS: To assess the validity of the Child Health Questionnaire (CHQ) as a screening tool for detecting 'at risk' emotional and behavioural maladjustment in children with diabetes, using the Behaviour Assessment System for Children (BASC) as a gold standard measure. METHODS: CHQ and BASC were administered to 103 parents of children with Type 1 diabetes, aged 7-12 years. Sub-scales of the two measures were compared using Pearson's bivariate correlations. CHQ sensitivity and specificity cut-points were optimized against the BASC borderline category using receiver operating characteristic curves. RESULTS: The BASC Externalizing Problems scale correlated strongly with CHQ Behaviour, Global Behaviour, Mental Health, Family Activities and Family Cohesion scales (r-values -0.68, -0.54, -0.51, -0.59, and -0.42, respectively). BASC Internalizing Problems scale correlated strongly with CHQ Behaviour, Mental Health and Family Cohesion scales (r-values -0.40, -0.43 and -0.45, respectively). Using receiver operating characteristic curve analysis, the CHQ Mental Health scale most effectively identified children classified as borderline on the BASC Internalizing Problems scale (sensitivity 87%, specificity 78%), while the CHQ Global Behaviour scale most effectively identified children classified as borderline on the BASC Externalizing Problems scale (sensitivity 73%, specificity 82%). CONCLUSIONS: Significant correlations were seen between the CHQ Global Behaviour and Mental Health scales and the BASC Externalizing and Internalizing scales, respectively. Sequential use of the CHQ, as a screening tool, followed by an established mental health measure such as the BASC, may help identify children with diabetes 'at risk' for chronic maladjustment and poor health outcomes.

Adjustment Disorders↗

PubMed2002

Regional and urban Victorian diabetic youth: clinical and quality-of-life outcomes.

OBJECTIVES: To compare groups of urban and regional Victorian diabetic children and assess their quality of life, diabetes knowledge, access to services and metabolic control. METHODS: Forty-seven children from three regional Victorian communities (Horsham, Warrnambool and Sale; n = 16, 18 and 13, respectively) were compared with 120 age-, sex- and duration of diabetes-matched children attending the Royal Children's Hospital (RCH) diabetes clinic in Melbourne. Quality of life, diabetes knowledge, use of services, and metabolic control were assessed using the child health questionnaire (CHQ PF-50/CF-80); a diabetes-knowledge questionnaire; access to a diabetes nurse educator (DNE), dietitian and complication screening; and indices of mean HbA1C (values are taken every 3 months in the 'yearly HbA1C'), respectively. RESULTS: Comparisons of CHQ data showed that regional diabetic youth scored significantly lower on most subscales. The greatest deficits were seen in areas of mental health, self-esteem, parent impact (emotional) and family cohesion. Diabetes knowledge and median yearly HbA1C for patients were not significantly different between the regional and urban centres (8.1%, 8.9%, 8.4% and 8.6% at RCH, Horsham, Warrnambool and Sale, respectively). Patients in regional centres had reportedly less access to team-based diabetes care. CONCLUSIONS: Regional youth in Victoria, with similar levels of metabolic control and diabetes knowledge as their urban counterparts, have a markedly lower quality of life, implying a negative synergy between diabetes and the demands of regional lifestyles.

Adolescent↗

PubMed2001

Deteriorating diabetic control through adolescence-do the origins lie in childhood?

AIMS: To determine whether intra-individual measures of diabetes control deteriorated through adolescence and whether HbA1c in late childhood was predictive of HbA1c after adolescence. METHODS: Retrospective analysis of sequential 3-6 monthly data including HbA1c, height, weight, and total daily insulin dosage in 118 patients with Type 1 diabetes aged between 8.00 and 17.99 years between 1983 and 1999. RESULTS: In females mean body mass index (BMI) increased sharply during adolescence but there was no significant increase in males. The mean total daily dose of insulin/weight (TDDI/W) increased sharply for females through puberty. Males exhibited a constant rate of increase in mean TDDI/W from pre- to post-puberty. There was a constant increase in mean HbA1c for females, with an estimated increase from pre- to post-puberty of 0.92%. In males there was only a slight increase from pre- to peri-puberty and no change subsequently. Comparing pre-puberty (8-9.99 years) and post-puberty (15-17.99 years) in the total group, 47% of patients remained in the same mean HbA1c grouping, 37% had worsened control and 16% had improved control. Analysis of change in the absolute value of mean HbA1c showed that the majority of patients had mean HbA1c values that remained within +/- 1% (54%) or +/- 2% (82%) from pre- to post-puberty. A significant proportion showed significantly worsening control with only a minority showing improved metabolic control from pre- to post-puberty. CONCLUSIONS: The likelihood of a significant improvement in HbA1c from late childhood to adolescence is remote, with the majority of patients having either constant or deteriorating metabolic control.

Adolescent↗

PubMed1999

Pituitary dysfunction, morbidity and mortality with congenital midline malformation of the cerebrum.

UNLABELLED: The purpose of this study was to review systematically a series of patients with congenital midline brain defects and pituitary dysfunction in early childhood and to quantitate the degree of dysfunction and clinical outcome. This study was a retrospective analysis of case notes of patients with pituitary dysfunction associated with either a midline cerebral anomaly and/or optic nerve hypoplasia. Forty patients were studied: 2 with semilobar holoprosencephaly, 2 with lobar holoprosencephaly, 18 with septo-optic dysplasia with an intact septum pellucidum, 7 with septo-optic dysplasia with an absent septum pellucidum, 7 with agenesis of the corpus callosum and 4 patients with isolated pituitary hypoplasia. An early age of diagnosis, feeding difficulties, neurodevelopmental disability, visual impairment and seizures were common occurrences. Despite disordered neuro-anatomy, most seizure disorders were caused by hypoglycaemia or hypernatraemia. Hypotensive/hypoglycaemic crises accounted for two out of three deaths within the study population. Most of patients had multiple pituitary hormone deficiency with growth hormone and adrenocorticotrophic hormone deficiency occurring most commonly. Unequivocal isolated hypothalamic dysfunction was an uncommon finding. In congenital midline brain malformation there is a spectrum of disordered neuro-anatomy associated with variable pituitary dysfunction. Clinical manifestations such as convulsions and developmental delay may be due to disordered metabolism and/or neuro-anatomy. CONCLUSION: Children with congenital midline brain defects frequently manifest convulsions, neurodevelopmental disability and poor growth due to disordered metabolism and/or neuro-anatomy. Treating clinicians must be aware of the complex, dynamic neurological and metabolic nature of these patients and their potential for early demise.

Abnormalities, Multiple↗

PubMed1999

A trial of growth hormone therapy in well-controlled hypophosphataemic rickets.

OBJECTIVE: Conventional therapy of hypophosphataemic rickets (HR) with oral phosphate and calcitriol does not always result in normal linear growth. Recombinant human growth hormone (rhGH) offers theoretical advantages as an adjunctive therapy. We aimed to determine the effects of adjunctive rhGH therapy in children with well-controlled HR. PATIENTS: In this report, 5 prepubertal children (aged 3.5-10.9 years) with well-controlled HR on conventional therapy were given adjunctive standard dose rhGH therapy for one year. DESIGN AND MEASUREMENTS: Height, growth velocity, metabolic markers of calcium and phosphate metabolism, body composition, bone mineral density, wrist and knee X-rays, and renal sonography were assessed at regular intervals. Height and growth velocities were also calculated 12 months after ceasing rhGH therapy. RESULTS: After 12 months therapy with rhGH, no significant biochemical or radiological benefits were observed. A significant increase in height SD score was observed (P = 0.023), but this was not associated with any increase in the growth velocity SD score and appears to have been due to catch-up growth caused by conventional therapy alone. When rhGH therapy was ceased, no significant decreases in mean height SD or growth velocity SD scores were observed. CONCLUSIONS: In well-controlled hypophosphataemic rickets patients receiving conventional therapy, adjunctive therapy with standard dose rhGH offers no benefits in linear growth or rachitic disease markers.

Body Composition↗

PubMed1999

Androgen secreting adrenocortical tumours.

BACKGROUND: Androgen secreting adrenocortical tumours are rare in children and the determination of their malignant potential can be difficult. OBJECTIVES: To assess the presentation, histology, and clinical behaviour of these tumours. SETTING: Two tertiary referral centres. STUDY DESIGN: Retrospective analysis of children diagnosed with an androgen secreting adrenocortical tumour between 1976 and 1996. PATIENTS: Twenty three girls and seven boys aged 0-14 years. RESULTS: Pubic hair was observed in all children, clitoromegaly or growth of the phallus in 23 children, acceleration of linear growth in 22 children, and advanced bone age (> 1.5 years) in 18 children. Hypersecretion of androgens was detected by assessment of serum androgen concentrations alone in four patients and by 24 hour urine steroid excretion profiles in 22 patients. All 16 tumours measuring < 5 cm in diameter were benign. Of the tumours measuring 5-9 cm, three were malignant and seven were benign, whereas all four tumours > 10 cm were malignant. Histological slides were available for reassessment in 25 children. Although mitoses and necrosis were more characteristic of tumours with malignant behaviour, no exclusive histological features of malignancy were seen. CONCLUSION: Histological criteria for malignancy are not reliable, whereas tumour size is important in assessing malignant potential.

Adolescent↗