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Biomedical subjects

G W Rylance

Publications and source records attributed to G W Rylance.

At least 19 recordsLinked to original sources
PubMed1998

Does a single plasma phenylalanine predict quality of control in phenylketonuria?

A 1993 MRC working group on phenylketonuria suggested standardising blood phenylalanine measurements by taking blood samples at the same time each day. Since it is not known how representative of a 24 hour period a single phenylalanine concentration is, the aim of this study was to investigate the 24 hour variability of plasma phenylalanine in well controlled children with phenylketonuria. Sixteen subjects, 12 girls and four boys aged 1 to 18 years, had hourly venous blood samples collected for 13 hours between 09.00 and 21.00 on one day. Serial skin puncture blood specimens were then collected at 24.00, 03.00, and 06.00 within the same 24 hour period. All food and drink was weighed. The median variation in plasma phenylalanine concentration was 155 mumol/l/day, with a minimum of 80 and a maximum of 280. The highest concentration occurred in the morning between 6.00 and 9.00 in 63% of subjects; the lowest occurred between midday and midnight in 94%. Concentrations < 100 mumol/l occurred in 46% of children below 11 years, three having concentrations < 30 mumol/l for two, six, and seven hours respectively. Three of five subjects had concentrations above the MRC guidelines for 24% of the period studied. Except in two subjects, the blood concentrations did not rise in response to phenylalanine consumption. However, the greater the quantity of protein substitute taken between waking and the 16.00 specimen, the larger the decrease in daytime phenylalanine concentration (r = -0.7030) (p < 0.005). There is therefore wide variability in phenylalanine concentrations in a 24 hour period in children with phenylketonuria which is not reflected in a single observation. Further study is needed to investigate the effects of timing of protein substitute on the stability of phenylalanine concentrations.

Adolescent↗
PubMed1994

Feeding problems in young PKU children.

Behavioural feeding problems were found to be more prevalent in a group of 15 PKU children aged 1-5 years when compared to non-PKU controls. The parents of PKU children identified poorer apatites (p < 0.01), a more limited range of foods consumed (p < 0.03) and more gastrointestinal symptoms such as vomiting and constipation (p < 0.03) than control children. The children were slower to feed (p < 0.03), were more likely to dislike sweet foods and some ate separately from the rest of the family at mealtime (p < 0.03). The effects on normal feeding behaviour should be considered when advocating strict diet therapy for young PKU children.

Case-Control Studies↗
PubMed1991

Parental permission, information, and consent.

One hundred and fifty parents of emergency paediatric admissions were interviewed; 60 of 106 (57%) blood samples were taken and 107 of 120 (89%) treatment regimens were instituted without their permission. Furthermore, the reasons for over half the blood tests and 31% of the drug treatments were not explained.

Child Health Services↗
PubMed1990

Rapid anticonvulsant monitoring in an epilepsy clinic.

The relevance of providing a rapid anticonvulsant monitoring service was assessed over a five year period at a paediatric epilepsy outpatient clinic. Altogether 481 drug assays were performed on 144 patients when considered clinically indicated. Drugs most frequently assayed were carbamazepine and sodium valproate, singly or in combination; sodium valproate, single or in combination; 90% of assays performed for phenytoin were from patients who were also taking another anticonvulsant. There were only six assays for ethosuximide and 10 for phenobarbitone. Physician's choice of drug dosage was recorded on a questionnaire before and after each assay result was known. Comprehensive patient details were analysed by a paediatric clinical pharmacologist, whose decision as to total daily anticonvulsant dosage was affected by knowledge of the drug concentration significantly less often than that of the clinicians for all the more commonly assayed drugs. There were a large number of drug assays that had no discernable clinical application. A more discriminating use of assays may both improve patient management and reduce considerably the number of anticonvulsant assays required.

Adolescent↗
PubMed1988

Use of drugs by children.

To obtain information on the use of prescribed and non-prescribed drugs in the general population of children 1590 children were surveyed in 1984-5 by weekly questionnaires filled out by parents. Drugs were taken in 13% of the 26 weeks studied and on 9% of the 182 days. Use in the summer and winter was similar. More than half (56%) of all drugs were taken on Saturdays and Sundays. Boys took drugs on 11% of days and girls on 8% of days. Almost half (45%) of drugs taken were not prescribed. Drugs acting on the respiratory tract and on coughs accounted for 42.2% of the drugs used. Analgesics were taken on 14.0% of days and antimicrobials on 12.5%. Aspirin accounted for 14.9% of all drugs used in any one week and for 31.7% of drugs obtained without prescription. Aspirin, paracetamol, triprolidine-pseudoephedrine (Actifed), ampicillin or amoxycillin, and salbutamol were the drugs most frequently used. The widespread use of drugs obtained without prescription suggests that community pharmacists and parents would benefit from further education on the choice of treatment in relation to symptoms. Doctors should be aware of the extent of treatment with non-prescription drugs and consider playing a greater part in advising on its indications.

Adolescent↗
PubMed1986

Medical teaching of the cultural aspects of ethnic minorities: does it exist?

The development of published material relating to the practice of medicine in multiracial and multicultural Britain is briefly reviewed. The utilization of such information in English medical schools is found to be absent or at a low level of priority. A more detailed study of one region demonstrates that junior hospital doctors believe from experience that they have a need for training in 'multicultural' medicine to serve their current patient load. Objective tests demonstrate the poor levels of knowledge and the role of practical experience. Responses from a survey of administrators and clinical tutors suggest interest or willingness to develop training in this field but a lack of coordination or resources. The paper demonstrates clearly that medical education has failed to keep pace with developments in the social and ethnic composition of the potential client population. Doctors who are practising in multiracial areas support this argument for changes in the undergraduate curriculum and extension of provision in postgraduate education. These improvements should not be confined to specific medical schools because of the career mobility of doctors, and by analogy could be extended to other medical professionals. Recommendations are made as a basis for a long-term strategy to ensure that medical education plays its part in combating racism in society.

Asia↗
PubMed1986

Plasma concentrations of clonazepam after single rectal administration.

Clonazepam was administered rectally to six children aged 1.4 to 4.7 years in a dose of 0.05 mg/kg and to five children aged 1.4 to 4.1 years in a dose of 0.1 mg/kg. Plasma concentrations indicate that it is rapidly absorbed, and it may therefore be an alternative to rectal administration of diazepam in continuing convulsions.

Benzodiazepinones↗
PubMed1985

Single dose pharmacokinetics of trimethoprim.

Single oral dose trimethoprim pharmacokinetics were determined in 18 children aged 3 months to 13 years. Trimethoprim suspension was rapidly absorbed and quickly and widely distributed. The mean clearance was considerably faster and the elimination half life considerably shorter than values reported in adults. Only one third of the administered drug dose was recovered from the urine within 24 hours which is considerably less than in adults, suggesting that children may metabolise a greater proportion of the dose given. Urine trimethoprim concentrations greatly in excess of minimum inhibitory concentrations for common pathogens were rapidly achieved and sustained for at least 16 hours.

Adolescent↗
PubMed1985

Re-evaluation of saliva for monitoring theophylline concentrations.

Variability of the mixed saliva/plasma theophylline relation was examined in seven children aged 2 to 13 years. Good correlation between plasma and saliva concentrations was found, but on the three occasions there was considerable inter- and intrapatient variability. There was no significant or consistent relation between unstimulated and stimulated saliva concentrations or between saliva concentrations and sample volumes. Plasma theophylline concentrations cannot be predicted accurately from saliva values.

Adolescent↗
PubMed1984

Carbamazepine 10,11-epoxide in children.

Concentrations of carbamazepine (CBZ) and its 10,11-epoxide metabolite (CBZ-E) were measured in simultaneously collected plasma and mixed saliva samples from 15 children (aged 1-13 years). Saliva concentrations of CBZ and CBZ-E were measured in hourly samples taken from six of these children during dose intervals whilst on different dose or dose-frequency regimens. Saliva and plasma CBZ (r = 0.91; P less than 0.001) and CBZ-E (r = 0.91; P less than 0.001) concentrations were significantly correlated. The mean +/- s.d. steady state CBZ-E/CBZ concentration ratio in the six children was 0.40 +/- 0.21 and was similar at all times within the 12 h dose interval. The mean +/- s.d. percentage fluctuation of the combined CBZ + CBZ-E (103.0 +/-28.9) was significantly less than that of CBZ-E (145.5 +/- 52.8) but not CBZ (109.6 +/- 31.1). If CBZ and CBZ-E have equipotent anticonvulsant activity in man, the contribution of CBZ-E approximates to 30% of total anticonvulsant effect in children taking CBZ alone.

Adolescent↗
PubMed1984

Theophylline dose prediction.

Two methods of predicting the optimal dose of theophylline in children aged 2 to 13 years were assessed. The observed plasma concentration was within 95% confidence limits of that predicted on eight of 14 occasions using a traditional multiple point pharmacokinetic method. Using a nomogram derived from the plasma concentration 6 hours after dosing and the logarithm of the calculated dose, which were significantly correlated, there was a significant relation between the dose predicted and the actual dose required to produce a concentration of 55 mumol/l.

Adolescent↗
PubMed1982

Saliva carbamazepine levels in children before and during multiple dosing.

1 Saliva carbamazepine (CBZ) pharmacokinetics were determined in six children aged 7-11 years at the start and after 5 weeks of CBZ therapy. 2 A single oral dose of CBZ, 14.7 +/- 2.3 mg kg -1, was administered and mixed saliva was collected at intervals during the next 36 h. CBZ therapy was then continued using the same total daily dose divided into two equal doses. After 5 weeks of therapy saliva samples were collected once more as on day 1. 3 The mean (+/- s.d.) saliva CBZ clearance increased over the study period from 142 +/- 28 to 402 +/- 79 ml h -1 kg -1 (P less than 0.001) and the mean half-life decreased from 23.6 +/- 5.3 to 8.0 +/- 2.3 h (P less than 0.005). The mean apparent volume of distribution after the first dose, 4.72 +/- 0.84 1 kg -1, was similar to that after 5 weeks treatment, 4.66 +/- 1.68 1 kg -1. 4 The mean saliva steady-state CBZ concentrations after 5 weeks therapy were less than 40% of those predicted from the single dose kinetic parameters.

Carbamazepine↗