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Biomedical subjects

C V Powell

Publications and source records attributed to C V Powell.

14 recordsLinked to original sources
PubMed1999

Leptomeningeal melanoma in childhood.

BACKGROUND: Malignant melanoma (MM) is one of the least common types of childhood cancer, accounting for less than 1% of all pediatric malignancies. Neurocutaneous melanosis (NCM) is a rare phakomatosis consisting of congenital abnormal pigmentation of the skin and meninges. The meningeal lesions are particularly prone to malignant change. METHODS: The authors describe 5 patients with NCM and 1 with primary leptomeningeal melanoma (LMM) seen at 2 treatment centers in the north of England over a 13-year period (1984-1997). RESULTS: The clinical features, progress, radiological findings, and treatment of these patients are discussed. All six died within eight months of their diagnosis, illustrating the difficulties faced in treating patients with these conditions. The authors reviewed the published literature on NCM, concentrating on the various therapeutic strategies that have been tried. Very little consistency in approach was found. Malignant skin lesions in NCM may be less responsive than primary malignant melanoma, but the small number of patients with primary LMM or brain metastases of MM make comparisons with NCM difficult. The authors' own series illustrates well the piecemeal nature of therapy for patients with these rare conditions. CONCLUSIONS: The rate of incidence of MM melanoma in the U.K. is increasing, and it will represent an increasing proportion of the pediatric oncologist's workload. A consistent approach to the therapy of patients with metastatic MM and NCM is needed if we are to have any hope of offering more than palliative therapy to these children in the future.

Central Nervous System Neoplasms↗
PubMed1998

Pulmonary function, exercise performance, and growth in survivors of congenital diaphragmatic hernia.

A cohort of survivors of congenital diaphragmatic hernia (CDH), with matched controls, was studied to assess growth, respiratory function, and exercise performance. Nineteen of 24 survivors from an 11 year period (79%) were compared with 19 matched controls. Subjects had detailed auxology, performed spirometry and cycle ergometry, and completed questionnaires about respiratory symptoms and exercise. There were no significant differences between the groups for height, weight, sitting height, head circumference, or body mass index expressed as SD scores. The mean (95% confidence interval) percentage predicted forced vital capacity (FVC) was 84.7% (79.1 to 90.3) in index cases and 96.5% (91.4 to 101.6) in controls (p < 0.01). There was no significant difference in total lung capacity. Expiratory flow rates corrected for FVC were also similar between groups, suggesting normal airway function relative to lung size. Mean maximum oxygen consumption in ml/kg/min was 40.1 (36.8 to 43.4) and 42.2 (38.5 to 45.8) in index and control cases. These differences were not significant. Index cases achieved a similar minute ventilation to controls by more rapid and shallower breathing. Index cases had lower perception of their own fitness and lower enjoyment of exercise, although habitual activity levels were similar. Survivors of CDH repair have reduced functional lung volumes, but normal airway function compared with matched controls. They have no growth impairment nor significant impairment of exercise performance, although they have more negative perceptions of their own fitness. They should be encouraged and expected to participate fully in sport and exercise.

Child↗
PubMed1998

Treatment of childhood asthma. Options and rationale for inhaled therapy.

Epidemiological studies suggest the prevalence of asthma is increasing, though some remain sceptical as to the magnitude or indeed the presence of an increase. However, despite improved diagnosis and the availability of the potent drugs now available there remains considerable respiratory morbidity associated with asthma. It is clear from a number of studies that failure to deliver drugs to the lungs when using inhaler devices is a factor contributing to this high level of morbidity. Failure of drug delivery may result from the prescribing of inappropriate devices, failure to use devices appropriately or failure to comply with a treatment regimen. For most of the currently available forms of asthma therapy there are significant advantages to be gained from administering them in aerosol form. The benefits to be derived from administering these drugs as an aerosol include a rapid onset of action for drugs such as beta-agonists and a low incidence of systemic effects from drugs such as beta-agonists and corticosteroids. Over the past 25 years our understanding of the nature of asthma has changed. Though this has been reflected in the emphasis on inhaled corticosteroid therapy in recent guidelines, it has not been reflected in the range of inhaler devices available. Manufacturers continue to place drugs such as corticosteroids in the same devices as short acting beta-agonists even though the requirements for these different drug classes are very different. It is likely that this contributes to suboptimal therapeutic responses with inhaled corticosteroids. However, the variability associated with current delivery systems is relatively small compared with the variability introduced by poor compliance. There is no work currently available to indicate how the use of cheap disposable devises which do not incorporate any form of positive feedback influence compliance with inhaled steroids. Optimising aerosolised drug delivery in childhood involves consideration of the class of drugs, the particular drug within a class but more importantly, the age and abilities of the child. Devices must be selected to suit a particular child's needs and abilities. Devices utilising tidal breathing are generally used such as spacing chambers or, less commonly these days, nebulisers. A screaming or struggling child, or failure to use a closely fitting mask, reduces drug delivery to the lungs enormously. Failure to respond to inhaled therapy in early childhood may be attributable to failure of drug delivery. Drug delivery in early childhood using current devices remains more an art than a science.

Administration, Inhalation↗
PubMed1998

Non-specific cough in children: diagnosis and treatment.

Cough is a common reason for parents to seek medical attention. When the history, examination, chest X-ray and, if possible, spirometry are normal, the cough can be classified as non-specific, which is often found. This article focuses on non-specific cough, addresses common questions and gives a simple approach to evaluating the child with a cough.

Asthma↗
PubMed1996

Longitudinal study of free running exercise challenge: reproducibility.

The reproducibility of free running exercise challenge has been examined in an unselected population of 8-10 year olds. Using a standardised protocol, monthly exercise tests were performed on 143 children over one year. A positive test was defined using both a 15% and 20% fall in peak expiratory flow after exercise. The mean (95% confidence interval, CI) population frequency for a positive test at 15% fall was 14.9% (6.5 to 23.3) and coefficient of variation 24.6%. For a 20% fall, the mean (95% CI) population frequency was 7.9% (2.9 to 12.9) and coefficient of variation 27.8%. Seventy two (50.3%) of the children gave at least one positive response at 15% fall. Exercise testing is not reproducible in the community setting and should not be used as a screening test. Exercise data from epidemiological studies of asthma should be interpreted with caution.

Asthma↗
PubMed1996

Stability of respiratory symptoms in unlabelled wheezy illness and nocturnal cough.

OBJECTIVE: To assess the natural history of respiratory symptoms not labelled as asthma in primary schoolchildren. DESIGN: Repeat questionnaire survey of subgroups identified from a previous questionnaire survey after a two year delay. SUBJECTS: The original population of 5321 Sheffield children aged 8-9 years yielded 4406 completed questionnaires in 1991(82.8%). After excluding children with a label of asthma, there were 370 children with current wheeze, 129 children with frequent nocturnal cough, and a random sample of 222 children with minor cough symptoms and 124 asymptomatic children. RESULTS: Response rates in the four groups were 233 (63.0%), 77 (59.7%), 160 (72.1%), and 90 (72.6%) respectively. Of those who initially wheezed, 114 (48.9%) had stopped wheezing and 42 (18.0%) had been labelled as having asthma. Those with more frequent wheezing episodes (p < 0.02) and a personal history of hay fever (p < 0.01) in 1991 were more likely to retain their wheezy symptoms. In the children with frequent nocturnal cough in 1991, 20.1% had developed wheezing, 42.9% had a reduced frequency of nocturnal coughing, and 14.2% had stopped coughing altogether two years later. One sixth had been labelled as having asthma. Children with nocturnal cough were more likely to develop wheezing if they had a family history of atopy (p = 0.02). Only 3.8% and 3.3% of those with minimal cough and no symptoms respectively in 1991 had developed wheeze by 1993 (1.9% and 1.0% labelled as asthma). CONCLUSIONS: Most unlabelled recurrent respiratory symptoms in 8-10 year olds tend to improve. Unlabelled children who have persistent symptoms have other features such as frequent wheezing attacks and a family or personal history of atopy. If a screening questionnaire were to be used to identify such children, a combination of questions should be employed.

Asthma↗
PubMed1995

Asthma treatment, perceived respiratory disability, and morbidity.

An entire school year of 8-9 year old schoolchildren in Sheffield were surveyed using the core questions of the international study of asthma and allergies in childhood in order to assess the morbidity associated with diagnosed asthma. Of 5321 children surveyed, replies were obtained from 4539 (85.3%). A current diagnosis of asthma was reported in 466 (10.3%), and a further 6.4% reported symptoms compatible with significant undiagnosed asthma. A validated questionnaire was used to assess symptoms and perceived disability in 336 (72.1%) of the children with diagnosed asthma. One third reported symptoms every day or most days, while 15.3% reported frequent nocturnal symptoms. There was no significant difference in reported symptoms between those receiving inhaled steroids, sodium cromoglycate, or no prophylaxis. Despite this, parents of children receiving inhaled steroids perceived more disability, and worried more about their children's health. It is concluded that perceived symptoms and morbidity are high in children with diagnosed asthma, and speculate that level of treatment is determined by parental tolerance of symptoms as much as by the symptoms themselves.

Administration, Inhalation↗
PubMed1994

Antioxidant status in asthma.

Reduced levels of glutathione peroxidase (GSH-Px) have been observed in adults with asthma. This study examines the antioxidant status in children with asthma compared with a control group in a cross-sectional analysis. Red blood cell GSH-Px, superoxide dismutase (SOD), and plasma concentrations of retinol, vitamin C, alpha tocopherol, and cholesterol were measured in 37 subjects (26 males) with stable controlled asthma. Thirty-five subjects (20 males) without eczema, hayfever, or recurrent respiratory symptoms were used as a control group. Children with asthma had significantly reduced red blood cell GSH-Px activity compared with controls [median (inter-quartile range) for asthma group, 10.25 (9.25-11.91); for control group, 11.75 (10.34-12.26) IU/g Hb; P = 0.006]. There were no significant differences in activity of SOD or vitamin C, retinol, or alpha tocopherol/cholesterol ratio. The reduction in GSH-Px activity may have therapeutic and etiological implications for asthma. The effects of disease activity and treatment on antioxidant status needs for further study.

Adolescent↗
PubMed1993

Poland anomaly with contralateral ulnar ray defect.

We report an atypical case of the Poland anomaly. Unreported features are that the hand abnormality is on the contralateral side to the chest wall defect, there is an ulnar ray predominance, and lack of syndactyly.

Fingers↗
PubMed1992

When will my baby go home?

The length of stay of preterm babies discharged from a neonatal nursery was determined and the predictive value of perinatal factors on the duration of stay was assessed on 762 preterm Salford born babies admitted to Hope Hospital neonatal unit between April 1986 and November 1990. The data were analysed using multiple logistical regression and forward stepwise regression analysis. Babies were discharged at a median (quartile range) postconceptional age of 36.3 (35.3-37.6) weeks. Seventeen factors were found to be strongly predictive of discharge date. The most significant predictive factor was gestational age accounting for 40% of variability compared with respiratory difficulties (6%), low birth weight (4%), sepsis (2%), and metabolic problems (1%). Most babies are discharged at approximately the same postconceptional age despite variations in their clinical course. Gestational age at birth is the most powerful predictive factor of time of discharge.

Bacterial Infections↗
PubMed1992

Delayed acute measles inclusion body encephalitis in a 9-year-old girl: ultrastructural, immunohistochemical, and in situ hybridization studies.

A 9-yr-old girl developed delayed acute measles inclusion body encephalitis, which was different from subacute sclerosing panencephalitis (SSPE) in clinical course. Measles virus was demonstrated by electron microscopy, immunohistochemistry, and in situ hybridization. Contrary to the most previous reports, matrix (M) protein was present in the brain, cerebrospinal fluid, and serum and was demonstrated by Western blot analysis and in situ hybridization. The hybridization was performed by a nonradioactive digoxigenin method.

Antigens, Viral↗
PubMedDate not supplied

Management of acute asthma in childhood.

In children, acute asthma is one of the most common reasons for admission to hospital. Morbidity and mortality from asthma are unnecessarily high. It is essential that all those caring for asthma patients can accurately assess and treat an acute exacerbation of asthma.

Acute Disease↗
PubMedDate not supplied

Asthma in childhood.

The prevalence of wheezy illness in children is increasing, along with the number of children diagnosed as having asthma. If physicians are to provide the most effective treatment for these patients, they need to be fully aware of advances in our understanding of the pathophysiology of asthma and of the new and improved treatments that these have brought about.

Asthma↗