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Biomedical subjects

B L Davies

Publications and source records attributed to B L Davies.

At least 37 records · Page 2Linked to original sources

Carrier detection in haemophilia a by immunological measurement of factor VIII related antigen (VIIIRAg) and factor VIII clotting antigen (VIIICAg).

23 obligate carriers of mild and severe haemophilia A and 26 normal females were bled on three occasions, and their plasmas assayed for procoagulant factor VIII (VIIIC), factor VIII related antigen (VIIIRAg) and factor VIII clotting antigen (VIIICAg). A comparison of the ratios VIIIC/VIIIRAg and VIIICAg/VIIIRAg indicated that, although the two ratios gave the same proportional misclassification of carriers as normals (four of 23), the latter ratio showed greater discriminatory power when an unequal variances predictive method was used to calculate likelihood ratios (for carrier status). This greater power was shown to be due to a greater reproducibility between visits for the VIIICAg/VIIIRAg ratio. Discrimination was considerably better when the median of the three median values for each variable was analysed, compared to the median value obtained at the first visit. There was also no statistical difference between VIIICAg/VIIIRAg (or VIIIC/VIIIRAg) ratios obtained from carriers of severe compared to mild haemophilia.

Antigens↗

Factor VII and fibrinolytic response to deamino-8-D-argenine vasopressin in normal subjects and dissociate response in some patients with haemophilia and von Willebrand's disease.

Deamino-8-D-argenine vasopressin (DDAVP) was given by intravenous infusion to normal subjects, haemophiliacs and patients with von Willebrand's disease (vWd) and the factor VIII and plasminogen activator response was studied. In normal subjects and most patients with mild haemophilia and mild (intermediate) von Willebrand's disease there was an increase in plasminogen activator and all factor VIII related activities. In patients with mild vWd the prolonged bleeding time was shortened by DDAVP despite only a modest rise in factor VIII related Ristocetin cofactor activity (VIIIR:RiCoF). Sub-groups of patients have been characterized in whom atypical responses was observed. In two brothers with clinically severe haemophilia, but with 5--6 u/dl procoagulant factor VIII (VIIIC), there was an increase in VIIIC but no rise of the corresponding antigen, suggesting increased release of an antigenically abnormal poorly functioning molecule. A patient with intermediate vWd was studied in whom neither DDAVP, adrenaline infusion, nor venous occlusion resulted in an increase in either plasminogen activator or factor VIII related antigen (VIIRAg), although there was a significant increase in VIIIC. In a further patient with severe vWd, DDAVP failed to elicit any plasminogen activator or VIII response. The results obtained from these two patients suggested that in some individuals the presumed endothelial cell abnormality in vWd may be more extensive than a defect in VIIIRAg synthesis. Sub-groups of patients have been identified for whom treatment with factor VIII concentrates would be more appropriate than DDAVP prior to minor surgery.

Adolescent↗

Prenatal testing for birth defects and nursing practice.

Recent advances in the prenatal diagnosis of birth defects including amniocentesis, ultrasound and fetoscopy are discussed. Indications, technical considerations and limitations are presented. Parental reactions to the stresses encountered during the process of prenatal diagnosis are related. Implications are identified for nursing care practice in different clinical settings including prenatal diagnostic units, paediatric services, obstetrical services and in the community.

Chromosome Aberrations↗

Attitudes towards school among early and late maturing adolescent girls.

The aim of this investigation was to test the hypothesis that early developing adolescent girls have a less favorable attitude towards school than late developers. The Ss were 104 grammar school girls of mean age 14 years 1 month. All Ss were given Fitt's test of attitude towards school. Twenty-two pairs of early and late developers, matched for chronological age, IQ, and social class, were compared with regard to their mean attitude score and their responses to individual items of the attitude scale. The early developers were found to have a significantly less favorable mean attitude score. There was also a tendency for more early developers to endorse unfavorable items and for more late developers to endorse favorable items.

Adolescent↗

Effectiveness of a pregnancy smoking cessation program.

OBJECTIVE: To evaluate two nursing approaches to promoting smoking cessation during initial antenatal visits. DESIGN: Experimental, with assignment to interventions using a random, alternate-day strategy and blind assessment of smoking at baseline, 1 month postintervention, 36 weeks' gestation, and 6 weeks postpartum. SETTING/PARTICIPANTS: 224 daily smokers, fewer than 31 weeks gestation, during first prenatal visit, at a teaching hospital antenatal clinic. INTERVENTIONS: An evening class providing guidance on a self-help program for 2 hours on a group basis or 20 minutes on an individual basis during the prenatal appointment. MAIN OUTCOME MEASURE: Smoking cessation, confirmed by urinary cotinine levels. RESULTS: All women assigned to the referral intervention received a referral, but none attended the classes. In contrast, 93% assigned to the immediate intervention received the intervention. The group receiving immediate intervention had two to three times higher rates of cessation at all follow-up periods, with significant differences at the 1-month follow-up. There were certain similarities between the groups. CONCLUSION: Cessation interventions should be administered during the first prenatal visit.

Adult↗

Evaluation of the "Time to Quit" self-help smoking cessation program.

Public health and hospital nurses have widespread contact with smokers; an effective smoking cessation program administered by nurses has tremendous potential. This study evaluated: 1) the effectiveness of the self-help cessation program, "Time to Quit"/"Moi aussi, j'écrase" (TTQ), provided on a one-to-one basis; and 2) a smoking cessation training program for baccalaureate nursing students. Nursing students recruited 307 smokers who were randomly assigned to receive one of two interventions. Control smokers received a list of community smoking cessation resources and experimental subjects received this list plus TTQ. Smoking self-reports and cotinine levels were obtained at baseline, six weeks and nine months. More smokers receiving TTQ had reduced at six weeks post-intervention, while there were no differences in quit or reduction rates at the nine-month follow-up. Students were positive about learning the techniques and their knowledge scores were significantly higher than those of non-participating students.

Adult↗