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Biomedical subjects

D Christie

Publications and source records attributed to D Christie.

At least 19 recordsLinked to original sources
PubMed2005

A repetitive movement detector used for automatic monitoring and quantification of scratching in mice.

We have designed an economical non-invasive movement detector for small animal studies and used it for monitoring and quantifying itch in mice. The system is based on a sensitive force transducer positioned below a recording platform holding a lightweight polystyrene recording box in which an animal is placed. A programmed micro-controller is used to discriminate between non-specific movement, grooming behaviour, and scratching movements made by the animal's hind limb. Following sub-dermal injection of histamine receptor agonists into the neck of a mouse, dose-related scratching occurred which was detected and quantified. There was 91% correlation between bouts of scratching as counted manually from playback of the video recording and recorded by the detector. The detector was also able rapidly to count the individual scratch movements of the hind limb that comprise a bout, with 95% accuracy in comparison with manual counting during slow motion playback of video tape, something that is impossible for an unaided observer to achieve because individual scratch movements are too fast to discriminate by eye. Separate detectors were used for the efficient non-invasive study of four animals simultaneously, and this number could easily be increased by adding more platforms. The system could also be modified to record the animal's position within the box, which would be of value in studies involving exploratory behaviour. In summary, the non-invasive multichannel repetitive movement detector will be very useful for accurate measurement of scratching during pruritus studies in small animals, with considerable savings in staff time and effort. It should therefore be a valuable tool for helping to investigate pruritus and in the evaluation of anti-pruritic drugs.

Animals↗
PubMed2005

Improving the accuracy of a photographic assessment system for breast cosmesis.

AIMS: To determine how the accuracy of a photographic system for cosmetic assessment of the breast after conserving treatment can be maximised. MATERIALS AND METHODS: Photographs of 40 women undergoing breast-conserving treatment for breast cancer were taken. Upward and lateral retraction was measured using a digitiser to enter the locations of reference marks on the photographs into a computer programme. In the readings produced, reduction in three potential sources of variation was considered by determining how few repeated photographs or measures were necessary to achieve an estimate within +/-2 mm of a mean value obtained from a large series. These included variation between assessments of the same photograph, between different photographs of the same patient and between different observers. We also sought to determine whether the attachment of white nipple markers (WNM) at the time of photography would reduce variation. RESULTS: A minimum of five readings was required from each photograph in order to obtain a result that was stable (defined as within 1 mm of that achieved by 20 readings). Using similar criteria, we found that at least four photographs of each patient were required, and that each should be assessed by at least four observers. The addition of WNM reduced the standard deviations by 36-45%. CONCLUSION: The use of WNM, which is simple, quick and cheap, is effective in reducing variation and can be recommended for use in clinical trials where overhead costs need to be contained.

Adolescent↗
PubMed2004

An unusual case of an atypical eating disorder masquerading as a serious multi-systemic illness.

UNLABELLED: An early diagnosis and multidisciplinary team approach are mandatory in the management of eating disorders. Serious organic symptoms and nutritional effects can mimic a systemic illness, particularly in those with atypical presentations. A 15-y-old adolescent male presented with poor growth, low weight, abdominal pain and yellow pigmentation. Further bizarre multi-system symptomatology resulted in a protracted admission with multiple investigations. An initial diagnosis of teratoma proved negative on abdominal laparotomy. A multidisciplinary approach followed by a feeding challenge led to the diagnosis of an eating disorder. The disorder, although more common in girls and adolescents, is increasing in incidence in both males and younger children. CONCLUSION: Atypical eating disorders are potentially serious and life-threatening illnesses, and paediatricians and psychologists should be aware of unusual presentations.

Abdominal Pain↗
PubMed2003

Motivational/solution-focused intervention improves HbA1c in adolescents with Type 1 diabetes: a pilot study.

AIMS: We piloted a motivational and solution-focused therapy group intervention to improve glycaemic control in young people 11-17 years with poorly controlled Type 1 diabetes (mean annual HbA1c >8.5%). METHODS: Seventy-seven subjects agreed to be assessed for a pilot non-randomized controlled trial. Subjects completed psychological questionnaires and were given feedback designed to encourage entry into the intervention. Twenty-one young people opted to enter the intervention groups (cases). Two intervention groups consisting of five to six subjects were conducted in each age band 10-13 years and 14-17 years. Twenty of those who did not opt to join the groups were randomly selected to act as controls. Cases and controls were well matched for age, HbA1c, duration of diabetes and socio-economic status. RESULTS: The intervention produced a significant improvement of 1.5% in HbA1c in cases (P<0.05) at 4-6 months post intervention compared with no change in controls. This improvement was partly maintained at 7-12 months post intervention. CONCLUSIONS: These pilot data suggest that a motivational/solution-focused group intervention is promising in improving HbA1c in adolescents and should be investigated further in a randomized controlled trial.

Adolescent↗
PubMed2003

Relapse patterns after chemo-radiation for carcinoma of the oesophagus.

AIM: The detailed review of patterns of failure in this report was undertaken to identify the continuing obstacles to the successful management of oesophageal cancer, and to establish whether there is a case to compare definitive chemo-radiation (Def-CR) and surgery for patients with squamous cancer in a randomized controlled trial. MATERIALS AND METHODS: First and subsequent sites of failure were reviewed in 274 patients treated with Def-CR using two cycles of cisplatin, infusional fluorouracil and 60 Gy; and 92 patients with limited chemo-radiation (CR), using one cycle and 35 Gy, followed by surgery (CR-Surg). All were treated on prospective non-randomized trials run by the Trans-Tasman Radiation Oncology Group between 1985 and 1999. Failure patterns were analysed using competing risks methodology, and pre-treatment variables predicting survival were identified by proportional hazards modelling. RESULTS: Site, stage, performance status and gender were independently predictive of survival following Def-CR. Local failure was evident in 42.3% of patients, but distant failure in isolation occurred in an additional 18.1%. Lowest rates of local and distant failure at 5 years (29.9% and 26%) occurred in patients with squamous cancer (SCC) located in the upper-third, whose 5-year survival was also the most favourable (49.2%). Survival was least favourable in patients with adenocarcinoma (AC) in the lower two-thirds (18.1%) due to higher rates of local (51.5%) and distant (36.1%) failure. Local failure occurred in 31.5% of patients undergoing CR-Surg but distant failure in isolation was observed in a further 34.7%. Outcomes were least favourable in patients with AC of the lower-third in whom 57.7% failed distantly and 5-year survival was 3.8%. Response to pre-operative chemo-radiation was also strongly predictive of outcome. Patients with no residual cancer in the resection specimen had the lowest rates of local (0%) and distant (16.7%) failure and the best survival (64.9%). Survival in patients with residual cancer in nodes, however, was extremely poor (3.5%) with distant failure occurring in 66.7%. CONCLUSION: The concurrent administration of chemotherapy with radiotherapy seems to have improved loco-regional control and has exposed distant failure as an obstacle to further improvements in outcome. Site, histological subtype, gender and response to chemo-radiation may predict biological differences in oesophageal cancer (OC) that influence outcome. A good case for a randomized comparison between Def-CR and CR-Surg in patients with SCC in the lower two-thirds exists.

Adenocarcinoma↗
PubMed2000

Clinical application of in vitro radiohypersensitivity testing.

The cases of two patients who suffered severe late effects of radiotherapy are reported; each tested positive for elevated in vitro radiohypersensitivity (RHS) but negative for the ataxia-telangiectasia mutation. The first patient underwent surgery and postoperative radiotherapy for lung cancer and subsequently developed fatal myelopathy. The second patient underwent triple-modality therapy for cervical cancer and suffered highly symptomatic pelvic fibrosis. The value of the testing was that it increased the confidence in the diagnosis of radiation effects and enabled suitable treatment to proceed. An increasing role for clinical RHS testing is anticipated.

Adult↗
PubMed1998

Cardiothoracic ratio and relative heart volume as predictors of coronary heart disease mortality. The Whitehall study 25 year follow-up.

AIM: To examine the association of radiographic measures of heart size with mortality from coronary heart disease. METHODS AND RESULTS: One thousand, one hundred and ninety-one male civil servants aged 40-69 years were followed-up for mortality over 25 years in relation to cardiothoracic ratio and relative heart volume. A high cardiothoracic ratio and relative heart volume predicted coronary (n = 196 deaths) and all-cause mortality, but not respiratory or malignant mortality. After adjustment for age, systolic and diastolic blood pressure, the highest (> or = 0.47) compared to the lowest quintile of the cardiothoracic ratio (< 0.40) was associated with a rate ratio of 1.84 (95% CI 1.14-2.97) for the effect on coronary heart disease mortality. Further adjustment for heart rate, smoking, cholesterol, angina and ECG ischaemia had little effect, reducing the rate ratio to 1.65 (95% CI 1.01-2.70). Similar rate ratios were observed for relative heart volume. CONCLUSIONS: Cardiothoracic ratio within the range considered 'normal' in clinical practice predicted coronary heart disease mortality independent of established coronary heart disease risk factors. The relative heart volume, which uses measurements from the lateral as well as the posteroanterior chest X-ray, did not predict coronary heart disease any better than the cardiothoracic ratio. The extent to which left ventricular mass and systolic dysfunction-- pathophysiological correlates of the cardiothoracic ratio and relative heart volume--are independent risk factors for coronary heart disease should be further investigated.

Adult↗
PubMed1998

Evidence-based esthetic dentistry.

Evidence-based clinical practice integrates the best available evidence with clinical expertise. This article presents a clinical case scenario and, using a four-step, evidence-based approach, demonstrates how to (1) ask an evidence-based question; (2) search MEDLINE for the best evidence; (3) critically appraise the evidence; and (4) apply the evidence to the patient. The procedure is demonstrated with the sample question, Does bleaching of bonded porcelain veneers increase marginal leakage? A MEDLINE search strategy was developed for synonyms of the key words that best identify the problem, the intervention, and the outcome. The synonyms were combined using the Boolean operator "or" to identify a "sensitive" (i.e., inclusive) universe of 140,000 journal articles. These categories were then combined using the Boolean operator "and" to identify the most "specific" (i.e., exclusive) four articles from among the 140,000. Finally, to find the best evidence, the articles were limited to "humans" and "randomized controlled trials." This identified one article. Critical appraisal of the limited data in this one article indicates that the methods are valid and statistically significant, but because of the methods employed, may not be clinically important. Evidence-based methods take one to the edge of the available information universe in about 15 minutes. The results can be both exhilarating and sobering. They can indicate the depth or limits of available information and suggest gaps in the knowledge-base that require further study. Most importantly, however, the results allow practitioners to communicate incisively and truthfully with patients and to make more informed clinical choices.

Aged↗
PubMed1997

Childhood-onset anorexia nervosa: towards identifying a biological substrate.

OBJECTIVE: The etiology of anorexia nervosa is not fully understood, but is probably multifactorial, including a biological substrate. The purpose of this paper is to investigate the possible underlying biological substrate. METHOD: Fifteen children and adolescents aged 8-16 years underwent regional cerebral blood blow radioisotope scans. All fulfilled DSM-IV criteria for anorexia nervosa. Three of the girls had a follow-up scan when they had regained their lost weight. RESULTS: Thirteen of the 15 patients had unilateral temporal lobe hypoperfusion, 8 on the left side and 5 on the right. The abnormality persisted in the 3 girls who had a follow-up scan after weight restoration. DISCUSSION: This is the first report of reduced regional cerebral blood flow in childhood-onset anorexia nervosa, and suggests an underlying primary functional abnormality.

Adolescent↗
PubMed1997

The occurrence of cancer in a cohort of New South Wales coal miners.

To describe the incidence of cancer in coal miners in New South Wales (NSW) between 1973 and 1992, an inception cohort of all male coal industry employees who entered the industry between 1 January 1973 and 31 December 1992 was constructed from the medical examination records of the Joint Coal Board. This cohort was matched with the NSW State Cancer Registry to determine the occurrence and type of cancer. In the cohort of 23,630 men, 297 developed 301 primary cancers in the 20-year period of observation. The standardised incidence ratio (SIR) for all cancers was 0.82. Stomach cancer has been reported to be common in coal miners but the SIR for stomach cancer was not higher than average in this cohort. A cluster of non-Hodgkin's lymphoma has been reported in a NSW coal mine but an increased risk of this cancer was not evident in the industry as a whole. Similarly a cluster of cases of brain tumour has been reported. In this cohort, the SIR for brain tumour was 1.05 (95 per cent confidence interval (CI) 0.57 to 1.76) and a risk for brain tumour remains unconfirmed. The SIR for malignant melanoma was 1.13 (CI 0.90 to 1.39) together and 2.02 (CI 1.31 to 2.98) for those workers who started in an open-cut mine. Overall, there does not appear to be a general risk of cancer in the NSW coal industry. Open-cut miners have an increased risk of malignant melanoma, which may be related to their exposure to the sun at work.

Adult↗
PubMed1996

Molecular requirements for assembly and function of a minimized human integrin alphaIIbbeta3.

Integrin subunit compatibility within and between species plays a major role in heterodimer assembly and ligand specificity. As an example, human alphaIIb pairs only with human beta3 and does not assemble a heterodimer with beta3 from other species. We use interspecies subunit chimeras to identify molecular requirements for subunit compatibility and show that species-restricted heterodimer assembly depends on a unique hexapeptide VGSDNH in an extended loop of the hypothetical human beta3 MIDAS domain. This allows us to express alphaIIb(1-233) and beta3(111-318) as a soluble, mini-integrin that retains RGD-dependent ligand recognition. Thus, in the case of one integrin, alphaIIbbeta3, the molecular requirements for integrin subunit compatibility and ligand recognition are intimately related.

Amino Acid Sequence↗
PubMed1996

Effects of hemispheric side of injury, age at injury, and presence of seizure disorder on functional ear and hand asymmetries in hemiplegic children.

Dichotic listening, manual functions, and IQ were measured in a large group of hemiplegic children with unilateral hemispheric damage. In the children without a history of seizure disorder, only manual functions were impaired, but in those with such a history (and hence a regime of anticonvulsant medication), all measures were affected. Some children with congenital left hemisphere lesions (with and without siezure disorder) showed a left ear advantage for dichotic digits as well as greater impairment in right hand function than those who showed the usual right ear advantage. The latter result suggests that the hemipheric damage in the subgroup with altered ear asymmetry was greater than in the others and extensive enough to encroach on language areas, shifting language representation to the right.

Adolescent↗