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Biomedical subjects

N Spencer

Publications and source records attributed to N Spencer.

At least 55 records · Page 3Linked to original sources
PubMed1999

Cerebral palsy in Malta 1981 to 1990.

Of 55200 Maltese children born in the Mediterranean islands of Malta and Gozo in the birth years 1981 to 1990 inclusive, 134 fitted the case definition of cerebral palsy (CP). Children were allocated to prenatal, perinatal, and postnatal groups according to strict criteria and to various CP syndromes using the Swedish classification. The study was undertaken between 1994 and 1996 and the period prevalence rate was calculated. The control group comprised 134 children who were matched for sex and born immediately before or after the index subjects in the same hospital. Data related to risk factors were extracted from medical records and collected by interview with parents/carers. Unadjusted odds ratios (OR) with 95% confidence intervals for a range of risk factors were calculated. For risk factors with a relatively high prevalence in the population, such as prematurity and low birthweight, ORs were calculated from case-control data. For low-prevalence risk factors, such as breech presentation and multiple pregnancy, ORs were calculated against the whole population data for the 10-year birth cohort. The prevalence rate of CP in the geographically defined, stable population of the Maltese islands was similar to that in the UK and higher than that for Sweden, but the rates for different types of CP were markedly different from most developed countries, with a higher rate of spastic tetraplegias. Risk factors were as expected and similar to those reported from other developed countries. The study shows a strong social gradient with a higher than expected proportion of CP in children of unskilled manual workers.

Adolescent↗
PubMed1999

The use of brief written educational material to promote reflection amongst trained nurses: a pilot study.

The UKCC (1995) suggest that in order for nurses to maintain their registration, they must maintain a personal professional profile via reflection, and there are numerous approaches to the teaching of reflection. Similarly, several models of reflection exist. However, much of this activity has occurred without attempts to establish the effectiveness of either reflection or attempts to teach it. The current study attempted to examine whether written educational material could significantly improve nurses' reflective ability. Nineteen practising nurses were recruited from a variety of sources and offered an educational package, largely based on Boud et al. (1985) model of reflection in learning. In a repeated measures design study, these participants completed a reflective exercise before and after offering of the educational material. Their scripts were rated, using Wong et al.'s (1995) tool, by three raters, two of whom were unaware of whether the scripts were completed before or after offering of the educational material. An initial analysis showed that there were no statistically significant changes in subjects' reflective ability following education. However, removal from the analysis of 6 participants who had a pre-test ability at the highest possible level (and for whom no improvement was, therefore, possible) resulted in a significant improvement in participants' ability from pre- to post-test (z = -2.4450, P = 0.0145). Interrater reliability calculated using Cronbach's Alpha was 0.7210 for pretest reflective accounts and 0.7369 for post-test reflective accounts.

Adult↗
PubMed1999

Socioeconomic status and birth weight: comparison of an area-based measure with the Registrar General's social class.

OBJECTIVE: To compare the relation of birth weight with socioeconomic status measured by an area-based measure of material deprivation and by the Registrar General's social class. SETTING: West Midlands Health Region 1991-93. STUDY DESIGN: Retrospective cohort study. METHOD: Birthweight data by enumeration district deciles ranked by Townsend Deprivation Index based on 1991 census data for all live births in the West Midlands Health Region were studied in three consecutive whole year birth cohorts, 1991 to 1993 and by Registrar General's social class in a 10% sample of live births (within marriage and jointly registered, provided by the Office of National Statistics) in the same region for the same period. Estimated proportions of births < 2500 g and < 3500 g "attributable" to social inequalities were compared for both socioeconomic status measures. The proportion of infants in each birthweight group were calculated for both measures. Relative risk (95% confidence intervals) of birth in each birthweight group for lowest versus highest socioeconomic status groups were calculated. RESULTS: The estimated proportions of births < 2500 g "attributable" to social inequalities were 30% using the area-based measure and 27% using the Registrar General's social class. For births < 3500 g, the estimated proportions were 12% for the area-based measure and 7% for social class. There was a positive linear relation between the proportion of babies weighing > or = 3500 g and increasing socio-economic status measured by either method. Gradients in the opposite direction were noted for the proportion of babies born in the other birth weight groups. Relative risk of birth weight < 3500 g was 1.30 (95% CIs 1.28, 1.32) for most versus least deprived decile and 1.17 (95% CIs 1.10, 1.25) for social class V versus I. For birth weight < 2500 g the risks were 1.99 (95% CIs 1.85, 2.18) and 2.04 (95% CIs 1.53, 2.73) respectively and for birth weight < 1500 g, 2.11 (95% CIs 1.73, 2.57) for most versus least deprived decile (numbers too small for analysis in the Office of National Statistics sample). CONCLUSION: A substantial proportion of births < 2500 g and < 1500 g are statistically "attributable" to social inequality. The results demonstrate that, using either socioeconomic measure, the likelihood of being born weighing > or = 3500 g, the most advantageous group, is substantially greater in the socially advantaged. Using the area-based measure, an estimated 12% of births < 3500 g could be ascribed to social inequalities whereas the same figure using social class was 7%. These findings suggest that this proxy measure of socioeconomic status may be a better discriminator in the study of pregnancy outcomes in this population than classification by occupational social class. Another advantage is its almost universal availability in routine records and its universal population coverage.

Birth Weight↗
PubMed1996

Deprivation and bronchiolitis.

OBJECTIVE: To test the hypothesis that socioeconomic deprivation is associated with an increased risk of admission with clinically suspected bronchiolitis. DESIGN: Case-control study. SETTING: Children under 1 year living in Sheffield in 1989-90. SUBJECTS: 307 children resident in Sheffield admitted to Sheffield hospitals with clinically suspected bronchiolitis between 1 October 1989 and 28 February 1990. METHODS: Children admitted with clinically suspected bronchiolitis were ascertained from laboratory records of nasopharyngeal aspirates cultured for respiratory syncytial virus. Case notes were examined to determine whether these children had required medical intervention and postcode of residence was recorded. Controls were selected from the Sheffield child development study (SCDS) data. Postcodes were converted to electoral wards which were assigned Townsend deprivation index scores. Electoral wards were then categorised by Townsend score into five levels of deprivation. Data on family smoking for cases and controls were extracted from the SCDS. RESULTS: Of the 307 children admitted with suspected bronchiolitis during the study period, 127 required one or more medical intervention. The risk of admission with clinically suspected bronchiolitis and with bronchiolitis requiring medical intervention rose with increasing level of deprivation score of electoral ward of residence. Children living in electoral wards in the two more deprived groups were more than 1.5 times as likely to be admitted (odds ratio (OR) 1.67, 95% confidence interval (CI) 1.25 to 2.24) or admitted requiring a medical intervention (OR 1.74, 95% CI 1.16 to 2.62) than children living in other parts of the city. Similar results were obtained after exclusion of children living in homes classified as smoky by the health visitor. CONCLUSION: Residence in an area of social and material deprivation increases the risk of admission with bronchiolitis even after taking account of parental smoking and when only more severe cases were considered.

Bronchiolitis↗
PubMed1996

Smoking and other health related behaviour in the social and environmental context.

It seems clear that parental smoking is harmful, although the magnitude of its effect may be smaller than sometimes suggested. However, smoking and other behaviours detrimental to health must be seen within a social and historical context. Individuals are not 'free choosing actors' and their behaviour is determined, at least in part, by their social and environmental circumstances. Smoking might better be regarded as a 'proximal' cause. 'Proximal' causes such as infectious or toxic agents are themselves subject to 'causes of causes' which are the determinants of exposure to these agents. Smoking may act as the 'proximal' cause, directly harming the fetus, but is itself caused by factors in the social and environmental circumstances. The complexity of the relationship between social and environmental circumstances, health related behaviours, and adverse outcomes cannot be resolved by the search for single causative agents. As Rutter points out, in order to begin to understand causal complexity 'it is necessary to examine distal causal relationships in the form of chains and of linked sequences involving several different, relatively short-term effects or operations' (p 2). Health promotion programmes sensitive to social context avoid 'victim blaming' and acknowledge that it is not enough to exhort mothers to 'stop smoking before and during pregnancy because this will harm your baby' (p 99). Mothers know that smoking can harm themselves and their babies and the vast majority want to give up. Their choice is limited by their social circumstances, and failure to recognise this has ensured the failure of health promotion initiatives aimed at smoking reduction during pregnancy. There are limitations in the techniques available to control for confounding in multivariate analysis and results must be interpreted with caution. Misinterpretation can lead to overemphasis of the role of single factors, diverting attention from complex pathways. While health related behaviours may be a 'proximal' cause of ill health, there is a duty on researchers, health promoters, and health policy makers to take account of the complex causal pathways in which these 'proximal' causes lie.

Child↗
PubMed1996

Race and ethnicity as determinants of child health: a personal view.

'Race' and ethnicity are widely studied as explanatory variables in health research and their apparent independent effects are reported to explain many health variations between different groups within and between populations. Both, however, are associated with major problems of definition and confusion of socio-cultural and biological concepts which call into question the validity of many of the 'independent' effects attributed to them. This paper seeks to unravel the basis of these concepts and explore their scientific validity using examples from the child health literature.

Child↗
PubMed1994

Valproate-mediated disturbances of hemostasis: relationship to dose and plasma concentration.

Valproic acid (VPA) may cause impaired platelet function, thrombocytopenia and, occasionally, severe bleeding. Controversy exists both as to the mechanism of this alteration in hemostasis and as to whether these adverse effects are either dose-related or idiosyncratic. Previous investigations have focused primarily on pediatric patients who commonly were receiving multiple anticonvulsant medications. We evaluated a cohort of 27 adult patients with epilepsy who were receiving VPA monotherapy and compared them with age-matched controls to determine whether a correlation exists between platelet count, function, bleeding time, levels of von Willebrand's factor antigen, and VPA dose or plasma concentration. VPA patients had significantly lower platelet counts and longer bleeding times than did controls (p < 0.05). Platelet count was inversely correlated to VPA dose and both free and total VPA concentration (p < 0.01). There was no significant difference in levels of von Willebrand's factor antigen between patients and controls. We assessed platelet aggregation by measurement of whole-blood platelet aggregation and release with agonists including adenosine diphosphate, thrombin, collagen, arachidonic acid, and ristocetin. VPA patients had significant decreases in platelet aggregation values compared with controls. There were significant differences in collagen, arachidonic acid, and adenosine diphosphate release and aggregation between groups that correlated to both VPA dose (p < 0.01) and concentration (p < 0.05). Prolongation of bleeding time was significantly correlated to both VPA dose and concentration. Our data suggest a significant relationship between impaired platelet function and both VPA dose and plasma concentration.

Adult↗
PubMed1993

Community indicators of child health.

Indicators of health in child populations are critically reviewed and the potential for routinely collected morbidity and life quality data discussed. A short list of currently available, routinely collected child health data is proposed which, if available for all European countries, would form the basis of a useable and comparable European child health data base. A European consensus group on child health indicators is proposed and further research into morbidity and life quality measures relevant to children recommended.

Adolescent↗
PubMed1985

Human erythrocyte carbonic anhydrase I concentrations in dried blood spots from normal and hypothyroid neonates and children.

The ELISA technique was used to assay carbonic anhydrase I (HCAI) in hemolysates prepared by the elution of dried blood samples from Guthrie cards. The ratio HCAI (mg)/hemoglobin (g) measured in blood samples eluted from Guthrie cards was not significantly different from that determined in aliquots of the same blood samples after storage as erythrocyte (RBC) lysates at -20 degrees C, provided that the dried blood was eluted within three weeks of collection. The normal neonatal mean (SD) RBC HCAI concentrations were 2.05 (1.01) and 1.82 (0.86) mg HCAI/g hemoglobin for females and males respectively. Erythrocyte HCAI concentrations gradually rose with age, approaching normal adult levels by 16 years. Blood from hypothyroid neonates and hypothyroid infants on treatment gave normal HCAI/hemoglobin ratios.

Adolescent↗
PubMed1985

Human carbonic anhydrase I concentration in erythrocytes during pregnancy and the menstrual cycle.

Carbonic anhydrase I (HCAI) concentrations were measured in erythrocytes (RBC) taken from nine women at intervals throughout their pregnancies and from thirteen normal women during the menstrual cycle. No significant changes in RBC HCAI concentrations were found in any instance. Small changes which were found in RBC HCAI concentrations were within experimental error and did not correlate with any other measured parameter. Changes in RBC HCAI concentrations in six men over a four-week period were of similar order to that found in the thirteen normal women over a similar length of time.

Adolescent↗
PubMed1984

Amino terminal acetylation and protein synthesis in eukaryotes.

The amino terminal residue in many proteins is N-acetylated. Available evidence indicates that acetylation occurs during translation whilst the nascent polypeptide is still attached to the ribosome; with some proteins, like the actins, an additional acetylation step occurs which may be catalysed by cytoplasmic enzymes. Studies of protein synthesis in heterologous cell-free systems show that the enzymes which catalyse amino terminal acetylation are ubiquitous and such studies have provided insights into the effects of limitations in the supply of acetyl CoA in vitro. Evidence that availability of acetyl groups in vivo may in part determine the cellular concentration of N-acetylated proteins is examined in terms of the relative amounts of the aceylated fraction of foetal haemoglobin and carbonic anhydrase I in human erythrocytes. Tissue and developmental differences in the concentration of the muscle isoenzyme, carbonic anhydrase III, are considered in terms of changes in the activity and distribution of mitochondria in muscle. Finally, the possibility is discussed that differential effects of thyroid hormone on protein concentration might be partly due to an effect of the hormone on acetyl CoA availability via its action on mitochondria.

Acetyl Coenzyme A↗
PubMed1983

Purification, properties and assay of D-ribulose 5-phosphate 3-epimerase from human erythrocytes.

A direct assay procedure is described for D-ribulose 5-phosphate 3-epimerase (EC 5.1.3.1) which exploits differences in the c.d. spectra of substrate and product. The enzyme has been purified from human erythrocytes and was resolved by gel filtration and sucrose-density-gradient centrifugation into a major component of apparent Mr 45 000 and a minor component of Mr 23 000. Electrophoresis in sodium dodecyl sulphate gave a single component corresponding to Mr 23 000. Kinetic and sucrose-density-gradient centrifugation data indicate dissociation of the dimeric form of the enzyme into monomers of low specific activity; substrate favours the active dimeric form of the enzyme. At concentrations of the enzyme where both forms of the enzyme are present initial velocity data yielded a Hill plot with an interaction coefficient of approx. 2.0, indicating co-operative binding of substrate under these conditions.

Carbohydrate Epimerases↗
PubMed1982

The measurement of human erythrocyte carbonic anhydrase I by the enzyme linked immunosorbent assay (ELISA).

A method is described for the assay of human erythrocyte (RBC) carbonic anhydrase I (HCAI) by the enzyme linked immunosorbent assay. The method was found to be a simple, reliable and precise technique and gave a mean C.V. for 40 samples, assayed in quadruplicate, of 3.32% and a range of 0.84-5.9. The mean erythrocyte HCAI value and standard deviation for 20 normal men and women were respectively 16.9 +/- 3.4 and 15.4 +/- 2.1 mg HCAI/g haemoglobin. The use of heparin as an anticoagulant interfered with the assay resulting in apparent HCAI concentrations as low as 60% of those obtained using EDTA.

Animals↗
PubMed1980

An association between plasma progesterone and erythrocyte carbonic anhydrase I concentration in women.

1. Erythrocyte carbonic anhydrase I was measured by immunoelectrophoresis in blood samples taken at intervals during the menstrual cycle of 26 normal women. Plasma progesterone concentrations were also measured in 18 of these subjects. In every case, the erythrocyte carbonic anhydrase I concentration reached a maximum at that point in the cycle when there was maximum secretion of progesterone. Statistical analysis indicated that the observed changes in erythrocyte carbonic anhydrase I concentration are highly significant and that erythrocyte carbonic anhydrase I and plasma progesterone concentrations are significantly correlated. 2. In three pregnant subjects the erythrocyte carbonic anhydrase I concentration showed a steady increase up to term. 3. Women taking progestogens in contraceptive pills, in doses of 1 mg/day or greater, had significantly higher concentrations of erythrocyte carbonic anhydrase I compared with females receiving no medication. 4. These observations strongly suggest that there may be a causal connection between plasma progesterone concentration and erythrocyte carbonic anhydrase I concentration in women.

Carbonic Anhydrases↗