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Biomedical subjects

J H McColl

Publications and source records attributed to J H McColl.

34 records · Page 2Linked to original sources
PubMed1996

Factors associated with the standard and duration of orthodontic treatment.

The pretreatment and post-treatment study casts and records of 156 completed fixed appliance and removable appliance cases were analysed, and the influence of various factors on the standard of result, as measured by the change in PAR score produced by treatment and the duration of treatment, was assessed. For the purpose of analysis the sample was divided into two groups; a two-arch fixed appliance group (n = 81) and a removable/mini fixed appliance group (n = 75). Multiple regression procedures were carried out separately for both groups, first, with all gathered data and, secondly, with only information which would be known at the start of treatment. For fixed appliances the initial PAR score was consistently an influential variable on change in PAR score and duration of treatment. Patient compliance, the need to extract a permanent first molar and the presence of an anterior crossbite were also important. The initial PAR score also explained much of the variation in change in PAR for removable/mini fixed appliances, but generally, regression models for this group were less well fitting.

Adolescent↗
PubMed1996

Ability of biolectric impedance to predict fat-free mass in prepubertal children.

Measurements of body composition are being made increasingly widely in pediatrics. Tetrapolar whole body impedance (BI) is particularly suitable as a method of estimating body composition in children and is therefore the subject of great interest at present. However, the ability of BI to accurately estimate fat-free mass (FFM) in children is unclear, and users of BI are faced with a growing choice of prediction equations for estimation of FFM. Studies in adults have suggested that choice of prediction equation can have a profound effect on the estimate obtained. The aim of the present study was to measure the ability of four published pediatric BI equations to predict FFM in 98 Caucasian prepubertal children (mean age 9.0 y). For three of the published equations, limits of agreement between predicted and reference FFM were wide and distinct biases were apparent. With mean FFM of 25 kg, the equation of L. Cordain et al. overestimated reference FFM (95% CI +2.1 to +3.1 kg), whereas those of P. Deurenberg et al. (95% CI -1.9 to -2.9 kg) and F. Schaefer et al. (95% CI -1.4 to -2.5 kg) systematically underestimated reference FFM. The equation of Houtkooper et al. (95% CI -0.2 to +0.8 kg) predicted FFM with negligible bias and had narrower limits of agreement relative to the reference method than the other three equations tested. We conclude that the ability of BI to predict body composition in children depends on the equation chosen and that the general applicability of BI equations cannot be safely assumed. Cross-validation of BI equations is recommended before they are used routinely for estimation of body composition in children.

Body Composition↗
PubMed1996

Comparison of photodynamic therapy with cryotherapy in the treatment of Bowen's disease.

The efficacy and suitability of photodynamic therapy (PDT) was compared with that of cryotherapy in the treatment of 40 lesions of Bowen's disease. Lesions were randomized to receive either cryotherapy with liquid nitrogen, or PDT using a portable desktop lamp incorporating a 300 W xenon short arc discharge source. A porphyrin precursor, 5-aminolaevulinic acid (5-ALA), was applied topically 4 h before irradiation in the PDT group. Each lesion received 125 J/cm2 at a fluence rate of 70 mW/cm2. All patients were reviewed at 2-monthly intervals and treatments repeated if required. Cryotherapy produced clearance in 10 of 20 lesions after one treatment, the remaining 10 lesions requiring two or three treatment applications. PDT resulted in clearance of 15 of 20 lesions after one treatment and of the remaining five lesions after a second treatment. The probability that a lesion cleared after one treatment was greater with PDT than cryotherapy (P < 0.01). Cryotherapy was associated with ulceration (five of 20), infection (two of 20) and recurrent disease (two of 20); no such complications occurred following PDT. PDT using a non-laser light source and topical 5-ALA appears to be at least as effective as cryotherapy in the treatment of Bowen's disease with fewer adverse effects.

Aged↗
PubMed1995

Outcome of Burkholderia (Pseudomonas) cepacia colonisation in children with cystic fibrosis following a hospital outbreak.

BACKGROUND: While there are reports on the outcome in adults and teenagers with cystic fibrosis of colonisation with Burkholderia (Pseudomonas) cepacia, there is little information in children. METHODS: In December 1991 only one of 115 children with cystic fibrosis attending a paediatric centre was colonised with B cepacia. Over the next 12 months there was a rapid increase with 23 (20%) becoming colonised; eighteen (79%) of these became colonised in hospital at a time that overlapped with the admission of a B cepacia positive child. Three different bacteriocin types were isolated, with one type (S22/PO) being present in 17 (74%) patients. The outcome for children who became colonised with B cepacia was compared with that in 33 children who continued to be colonised with Pseudomonas aeruginosa alone. RESULTS: Children colonised with B cepacia were older and more poorly nourished than those colonised with P aeruginosa, but did not have poorer pulmonary function. After colonisation, the forced expiratory volume in one second (FEV1) deteriorated between consecutive annual tests, with the average deterioration being greater in those with higher initial levels. Five children with B cepacia died from respiratory failure although none showed a fulminant deterioration. Introduction of segregation measures within hospital led to a dramatic decrease in the number of newly colonised patients. CONCLUSIONS: This study provides further evidence for person-to-person spread of B cepacia and confirms the effectiveness of simple isolation measures in interrupting spread. Colonisation with B cepacia and P aeruginosa in children is associated with a more rapid decline in lung function and a significantly increased mortality compared with cases colonised with P aeruginosa alone.

Adolescent↗
PubMed1995

Home nebuliser use in children with asthma in two Scottish Health Board Areas.

OBJECTIVE: To audit the use of home nebulisers in children with asthma. DESIGN: Postal questionnaire. SETTING: Two Health Board Areas in Central Scotland--one large industrialised city, one mixed urban and rural. SUBJECTS: 297 children with asthma. MEASURES EVALUATED: Initial supply and technical support for the compressor. EDUCATION: Pattern of drug usage. SYMPTOM CONTROL: Monitoring and treatment of acute attacks. RESULTS: The full burden of the home nebulised therapy is not being met by the NHS. Supply and servicing arrangements for home nebuliser therapy were poorly organised. Chronic asthma symptoms did not appear to be optimally controlled on present medication, with 61% reporting sleep disturbance in the previous three months. About 20% of parents admitted that they would give nebulised bronchodilator therapy more frequently than the recommended 3 to 4 hourly. CONCLUSION: Re-organisation of resources and arrangements could improve the service and bring it in line with recognised standards of care.

Acute Disease↗
PubMed1994

Factors influencing the outcome and duration of removable appliance treatment.

The study models and records of 150 consecutively completed removable appliance cases were analysed and the influence of various factors assessed on both the change in Peer Assessment Rating (PAR) score produced by treatment and the duration of treatment. For the purpose of analysis the material was divided into two groups; a functional appliance/headgear group (n = 43) and an upper removable appliance group (n = 103). The initial PAR score accounted for 71 per cent of the variation in PAR change in the functional/headgear group when combined with the sex of the patient; females on average showing a further improvement of 3 PAR points over equivalent males. The initial PAR score alone accounted for 68 per cent of the variation in PAR change in the upper removable appliance group. Sixty per cent of the variability in treatment duration could be explained in the functional/headgear group by the initial PAR score and a binary variable indicating whether three or more appliances had been required. Fifty-six per cent of the variability in duration in the upper removable appliance group was explained by the number of appliances used alone. Regression equations for prediction of outcome and duration of removable appliance treatment are given.

Adolescent↗
PubMed1994

Does weight for height have prognostic significance in children with acute lymphoblastic leukemia?

PURPOSE: We tested the hypothesis that weight for height, a simple index of nutritional status, is related to prognosis in childhood acute lymphoblastic leukemia (ALL). PATIENTS AND METHODS: The study population was composed of 78 children with ALL tested at one U.K. center on the same protocol (UKALL-X). Outcome measures were relapse/no relapse and time to first relapse. Influence of weight for height, expressed as standard deviation scores, was tested using survival analysis in a retrospective design. RESULTS: The weight-for-height standard deviation score had a significant influence on time until first relapse (log ranks test, p = 0.012), with the highest risk of early relapse in children at the lower end of the weight-for-height distribution. CONCLUSIONS: The results suggest that weight for height does have an influence on outcome in ALL, but the mechanism is unclear and the finding requires confirmation by larger scale prospective studies.

Adolescent↗
PubMed1994

Statistical methods in neuroimaging with particular application to emission tomography.

We review statistical methods being applied in four key areas connected with PET and SPECT neuroimaging: (i) image reconstruction (briefly); (ii) tracer-kinetic, or compartmental, modelling; (iii) inference from region-of-interest data; (iv) inference at the pixel or voxel level. Under the last heading, we pay particular attention to the analysis of data from serial scans. We conclude by identifying some topics for future statistical research.

Algorithms↗
PubMed1993

Use of the PAR index in assessing the effectiveness of removable orthodontic appliances.

The dental study casts of 150 consecutively completed removable appliance cases were examined before and after orthodontic treatment using the PAR index. Eighty-nine per cent were classified either as 'improved' or 'greatly improved'. Of the 16 cases classified as 'worse, no different', six were mixed dentition cases with limited treatment objectives (which were successfully achieved) and three were permanent dentition cases where only one tooth was being aligned. Using predefined criteria removable appliances were shown to be most effective in treating cross-bites, ectopic tooth position, anterior spacing, and overjet, and less effective in treating crowding, rotations, and molar relationships.

Adolescent↗
PubMed1992

Prospective controlled study of four infection-control procedures to prevent nosocomial infection with respiratory syncytial virus.

To determine the most effective infection control procedure in preventing nosocomial infection with respiratory syncytial virus (RSV), we did a prospective controlled study of four infection-control strategies in four wards in a large paediatric hospital in the west of Scotland. All children under two years old admitted to four general wards during three winter RSV epidemics (1989-92) were screened for RSV infection (by nasopharyngeal aspirate and direct immunofluorescence) within 18 hours of admission. The main outcome measure was the occurrence of nosocomial infection, defined as the number of children initially RSV negative who became RSV positive 7 days or more after hospital admission (incubation period for RSV infection is 5-8 days). Without special precautions, there was a high rate of nosocomial RSV infection (26%). Nosocomial infection was significantly reduced by the combination of cohort nursing with the wearing of gowns and gloves for all contacts of RSV-infected children (p = 0.0022). Neither the use of gowns and gloves alone nor cohort nursing alone produced a significant reduction in cross-infection. In the final year, general clinical use of a policy of cohort nursing with gowns and gloves resulted in a reduction in the cross-infection rate by two-thirds of its original value (9.5% vs 26%). Combined with rapid laboratory diagnosis, cohort nursing and the wearing of gowns and gloves for all contacts with RSV-infected children can significantly reduce the risk of nosocomial RSV infection.

Antibodies, Viral↗
PubMed1991

Statistical issues in the analysis of neuroimages.

Statistical issues in the analysis of neuroimages are reviewed. These include biological questions of interest, basic problems of measurement and experimental design, normalisation, standardisation and transformation, and statistical methodology. Finally, three data sets are reviewed to illustrate some of the issues raised in the report.

Alzheimer Disease↗
PubMed1990

Measurements of regional cerebral blood flow and cognitive performance in Alzheimer's disease.

Single photon emission computed tomography (SPECT) with 99mTc-HMPAO was used to image 26 patients with dementia of the Alzheimer type (DAT) and 10 healthy controls. Regional cerebral blood flow (rCBF) data indicated a relative sparing of the occipital regions in DAT. Normalisation to occipital flow illustrated highly significant CBF deficits in a number of cortical regions, particularly in the left and right posterior--temporal cortex in DAT compared to controls. The cognitive performance of DAT patients was measured using a clinical cognitive assessment procedure (CAMCOG) and numerous correlations between these scores and rCBF were obtained. The implications and value of this investigative technique are discussed.

Aged↗
PubMedDate not supplied

No evidence for an effect of nutritional status at diagnosis on prognosis in children with acute lymphoblastic leukemia.

PURPOSE: To test the hypothesis that nutritional status at diagnosis, defined as body mass index standard deviation score (SDS), is related to the prognosis in childhood acute lymphoblastic leukemia (ALL). PATIENTS AND METHODS: The sample consisted of 1,025 patients with standard risk ALL who had been randomized to different intensification therapies. Outcome measures were relapse/no relapse and time to first relapse. The influence of body mass index SDS was tested by survival analysis. RESULTS: There was no evidence that body mass index SDS was related to clinical outcome (proportional hazards model, p = 0.72). CONCLUSIONS: The study results suggest that nutritional status at diagnosis, defined on the basis of the body mass index, at least in developed countries, has no effect on the prognosis in ALL, and it should not be considered as a prognostic factor.

Adolescent↗
PubMedDate not supplied

Protein energy supplements in unwell elderly patients--a randomized controlled trial.

BACKGROUND: To determine whether oral protein energy supplements, prescribed during hospitalization to elderly medical admissions, affect nutritional status and if baseline nutritional state influences this status. We also considered the effects on mortality, length of hospital stay, functional recovery, and institutionalization. METHODS: A prospective randomized controlled trial with no placebo. Consenting patients were stratified in 3 nutritional categories, and patients from each stratum were randomized into treatment or control. Observers were blinded to randomization. The participants were emergency admissions from home to a Medicine for the Elderly Unit in a Scottish hospital. The inclusion criteria were as follows: no known malignancy, the ability to swallow, and nonobesity (BMI < 75th percentile). The intervention was a prescription of 120 mL sip feed, 3 times daily (540 kcal, 22.5 g protein per day) throughout hospitalization, using the medicine prescription chart. The trial was powered to detect change in mean percentage weight. The following outcomes were also considered: anthropometry; mortality, length of hospital stay, functional recovery, and rates of institutionalization. RESULTS: Included in the trial were 381 patients. Nutritional supplementation was associated with significantly better energy intake (p = .001) and weight gain (p = .003) pooled across all nutritional categories. In the most poorly nourished patients, the intervention was associated with reduced mortality (5/34 versus 14/40, p < .05) and more patients improved functionally (17/25 versus 11/28, p < .04). Overall mortality results were 21/186 versus 33/195, odds ratio (OR) 0.62, 95% confidence interval (CI) 0.35, 1.13. CONCLUSIONS: Prescribing sip feed supplements in the medicine prescription chart during hospital stay reduces weight loss. Our data also support other evidence for a reduction in mortality noted in elderly patients on nutritional supplementation. There were suggestions of other clinical benefits.

Aged↗