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Biomedical subjects

I Roberts

Publications and source records attributed to I Roberts.

At least 217 records · Page 12Linked to original sources
PubMed1994

Auckland children's exposure to risk as pedestrians.

AIM: To examine children's exposure to risk as pedestrians and to examine the extent to which child pedestrian exposure to risk varies by socioeconomic status and ethnic group. To identify factors which may influence child pedestrian exposure to risk. METHOD: A survey of 442 parents was conducted to examine how children travel to and from school and parental perceptions of the risk of pedestrian injury. RESULTS: There are considerable socioeconomic and ethnic differences in children's exposure to risk as pedestrians. The proportion of children who walked home from school in the lowest socioeconomic stratum (63.5%) was over twice that in the highest socioeconomic stratum (25.2%). A significantly higher proportion of Maori (61.2%) and Pacific Island children (74.6%) walked home from school compared with children of European origin (29.4%). For children from families without access to a car, the proportion who walk home from school (78.0%) was more than twice that for children from families with a car (36.7%). Parental perceptions of risk do not vary by socioeconomic status and ethnic group. CONCLUSION: The increased pedestrian injury rates for poor children and for Maori and Pacific Island children may be explained, in part, by the increased pedestrian exposure of these children. Increased pedestrian exposure is likely to reflect social and economic constraints, rather than differences in perceptions of the danger to children as pedestrians. Efforts to address the safety of children as pedestrians are urgently required.

Accidents, Traffic↗
PubMed1994

Prevalence of back pain among nurses.

AIM: To provide estimates of the occurrence of back pain among nurses employed in the public health sector in Auckland, New Zealand. METHOD: A cross sectional survey was undertaken of all nurses employed by the Auckland Area Health Board as at July 1992. RESULTS: The lifetime prevalence of back pain was 74.4%. The lifetime prevalence of nursing-related back pain was 62.3%; the annual prevalence was 36.8%; and the point prevalence was 11.6%. Pacific Island nurses had a higher annual and point prevalence of nursing-related back pain compared with New Zealand European and Maori nurses. The annual and point prevalence was also higher among those working on geriatric, medical, orthopaedic and rehabilitation wards compared with other nursing environments. CONCLUSION: This study found a high prevalence of back pain among nurses, and in particular, nurses working in four specific work environments were identified as having greatest risk. These findings provide support for the targeting of intervention strategies which focus on work organisational factors.

Adult↗
PubMed1994

Blaming children for child pedestrian injuries.

Pedestrian injuries are a leading cause of childhood mortality. In this paper a case study of a child pedestrian death is presented in order to examine the apportionment of responsibility for child pedestrian injuries. The case presented illustrates how responsibility is located with the child, whilst structural contributors, in particular aspects of the transport system, are ignored. The strength and pervasiveness of the ideology of victim blaming in child pedestrian injuries is explained by the special position that the road transport system holds in relation to dominant economic interests. Victim blaming ideology is a strategy that serves to maintain these interests at the expense and suffering of children. Increased recognition of the political roots of the ideology of victim blaming in child pedestrian injuries, by the sectors of the community who suffer its consequences, will be an important step towards effective preventive action.

Accidents, Traffic↗
PubMed1994

Differential recall in a case-control study of child pedestrian injuries.

I conducted a validation study to examine data collected in a case-control study of child pedestrian injuries for evidence of differential recall. I compared questionnaire responses for variables related to the safety of the home environment with direct observations of the same parameters. A comparison of all child pedestrian injury cases with all controls provided no evidence of differential recall. There was, however, differential recall for a subset of the cases, specifically those injured in residential driveways. For these cases, differential recall had a substantial effect on the odds ratio.

Accidents, Traffic↗
PubMed1994

In vitro culture of colony forming unit-megakaryocyte (CFU-MK) in fetal alloimmune thrombocytopenia.

Perinatal alloimmune thrombocytopenia (PAITP) causes intracranial haemorrhage in the fetus and neonate. However, the severity of the thrombocytopenia correlates poorly with maternal anti-platelet antibody titres. To test the hypothesis that reduced platelet production contributes to fetal thrombocytopenia in PAITP, maternal sera from three HPA-1a-negative mothers whose pregnancies were complicated by anti-HPA-1a (two severe cases, one mild case) were added to colony forming unit-megakaryocyte (CFU-MK) cultures from HPA-1a positive and negative individuals. Sera from the two severely affected pregnancies containing anti-HPA-1a caused 66-100% inhibition of HPA-1a-positive fetal and neonatal CFU-MK, whereas CFU-MK from two HPA-1a-negative mothers were not inhibited by the anti-HPA-1a-containing sera. Maternal serum from the case of mild PAITP caused only mild inhibition of HPA-1a-positive cord and adult CFU-MK and did not inhibit HPA-1a-positive fetal CFU-MK. Taken together, these findings suggest that reduced megakaryocyte production contributes to fetal thrombocytopenia due to maternal anti-HPA-1a antibodies and also that the degree of CFU-MK inhibition correlates with severity of fetal thrombocytopenia.

Adult↗
PubMed1994

Application of capture-recapture methodology to estimate the completeness of child injury surveillance.

This paper describes the use of the two sample capture-recapture method to estimate the completeness of ascertainment of injury events in both routine public hospital discharge statistics and in an active injury surveillance system. For all child pedestrian injuries public hospital discharge statistics were 90% complete and the active surveillance system 77% complete. For non-traffic child pedestrian injuries public hospital discharge statistics were 66% complete, the active surveillance system being 79% complete. Capture-recapture methods have the potential to improve the accuracy of traditional childhood injury surveillance systems.

Accidents, Traffic↗
PubMed1994

Sole parenthood and the risk of child pedestrian injury.

Children of sole parents have the worst mortality record of all social groups. Road vehicle related injuries account for a large part of their excess mortality. In this case-control study the association between sole parent status and the risk of child pedestrian injury was examined. Cases (n = 258) were children killed or hospitalized as a result of a pedestrian injury in the Auckland region over a period of 2 years and 2 months. Controls were a random sample of the child population. The children of sole parents were at a significantly increased risk of injury (odds ratio = 1.57; 95% confidence interval (CI) 1.09, 2.27). However, there was a striking difference in the effect of sole parent status according to ethnic group. Among European families, sole parenthood was associated with a greatly increased risk of injury (OR = 3.13; 95%CI 1.84, 5.31), whereas in Pacific Island families sole parenthood was associated with a significant protective effect (OR = 0.40; 95%CI 0.18, 0.89). The protective effect of sole parent status in Pacific Island families may reflect the beneficial effects of the social support provided by extended family networks. Children of sole parents in the context of the nuclear family may be particularly vulnerable.

Accidents, Traffic↗
PubMed1994

Environmental factors and child pedestrian injuries.

The aim of this study was to provide information on modifiable environmental factors at sites of child pedestrian injuries which would be useful for the design of preventive strategies. A total of 103 child pedestrian injuries was identified over a one-year surveillance period. Of these, 71 per cent occurred on public roads, 24 per cent occurred in residential driveways and 4 per cent occurred in car parks. For roadway injury sites, the median traffic flow was 635 vehicles per hour and the median speed was 49.0 kph. For 31 (42 per cent) roadway injury sites the median vehicle speed was in excess of the posted speed limit. The majority of roadway injuries occurred on residential streets. For driveway injuries there was no separation of the driveway from the children's play area in 75 per cent. Changes to the urban traffic environment which reduce traffic flows and vehicle speeds have the potential to prevent child pedestrian injuries. Controlled epidemiologic studies which examined the magnitude of the risks associated with modifiable environmental factors are required.

Accidents, Traffic↗
PubMed1994

Preventing child pedestrian injury: pedestrian education or traffic calming?

The traditional approach to the prevention of child pedestrian injuries in New Zealand is pedestrian education. However, none of the programs currently being implemented in New Zealand have ever been shown to reduce injury rates. The allocation of scarce resources to pedestrian education must therefore be questioned. In this paper we estimate the number of serious child pedestrian injuries which might be prevented if the resources allocated to pedestrian education were allocated instead to environmental approaches, in particular, to traffic calming. It is estimated that approximately 18 hospitalisations of child pedestrians could be prevented each year under this alternative resource allocation, disregarding any other benefits of traffic calming. These results emphasise the need to consider the potential sacrifices involved in the allocation of scarce resources to child pedestrian education.

Accidents, Traffic↗
PubMed1994

Genetic mapping of the FACC gene and linkage analysis in Fanconi anaemia families.

Fanconi anaemia is an autosomal recessive disorder associated with increased chromosome breakage and progressive bone marrow failure. The gene for complementation group C (FACC) has been cloned and mapped to chromosome 9q22.3, but neither its genetic location nor the proportion of patients belonging to group C is known. We have used a polymorphism within the FACC gene to localise it within a 5 cM interval on chromosome 9q, bounded by D9S196/D9S197 and D9S176. The genes for Gorlin's syndrome and multiple self-healing squamous epitheliomata have also been mapped to this interval. Linkage analysis with the three highly informative microsatellite polymorphisms flanking FACC in 36 Fanconi anaemia families showed that only 8% of families were linked to this locus. This indicates that the genes for the other Fanconi anaemia complementation groups must map to one or more different chromosomal locations. The markers also allowed rapid exclusion of 56% of the families in our panel from complementation group C, thus substantially reducing the number of patients who need to be screened for FACC mutations.

Chromosome Mapping↗
PubMed1994

Bone marrow transplantation in children: current results and controversies.Meeting, Hilton Head Island, SC, March 1994.

The first meeting devoted specifically to BMT in children took place on Hilton Head Island, SC, in March 1994 and included detailed reviews of the role of BMT in the management of diseases for which it has been a subject of considerable controversy: haemoglobinopathies (thalassaemia and sickle cell disease), metabolic storage disorders and neuroblastoma. The results of BMT using marrow donors other than HLA-identical siblings were presented, including data from a number of centres on the outcome in children transplanted from mismatched family donors. Experience of the collection and transplantation of alternative sources of haemopoietic stem cells in the paediatric age group has accumulated rapidly in recent years. The results of transplantation of peripheral blood stem cells and of umbilical cord blood stem cells indicate that both approaches may soon replace BMT as first-line treatment for some malignant and non-malignant disorders in children. While gene therapy offers exciting prospects for the future, it was discussed here principally as treatment for ADA deficiency and is likely to remain a more distant, although exciting, therapeutic option for many diseases currently treated by BMT.

Adenosine Deaminase↗
PubMed1994

Retroviral-mediated gene transfer of a mutant H-ras gene into normal human bone marrow alters myeloid cell proliferation and differentiation.

To investigate the effects of mutant ras expression on the growth and differentiation of normal human bone marrow, we used retrovirus-mediated gene transfer. A retrovirus (HR-1) containing a mutant ras gene (H12-ras) in addition to the selectable neo gene was transferred by cocultivation of a packaging cell line with long-term cultures of normal human bone marrow. Controls were established by cocultivating aliquots of the same bone marrow with a retrovirus (VSN-2) containing only neo. The efficiency of gene transfer, as determined by the percentage of G418-resistant colony-forming units-granulocyte/macrophage (CFU-GM) immediately after termination of cocultivation, was similar: 8 +/- 4% with HR-1 and 5 +/- 3% with VSN-2. After a further week in long-term culture, there was an increase in the number and percentage of G418-resistant CFU-GM in both the HR-1-infected and VSN-2-infected marrows. Thereafter, the numbers of G418-resistant CFU-GM declined, becoming undetectable at 4 weeks. The time course of the production of G418-resistant colonies was not significantly different in HR-1- and VSN-2-infected marrows, indicating that H12-ras did not alter the proliferation of normal CFU-GM. However, the total cellularity of HR-1-infected marrow cultures was significantly greater than that of VSN-2-infected marrow cultures. This was due to increased cellular proliferation of HR-1-infected cultured cells, since differential counts showed a significant increase in myeloid blast cells together with a slight reduction in mature myeloid cells in HR-1-infected marrow compared to baseline and to VSN-2-infected marrow. No leukemic blast cell colonies were grown from HR-1-infected marrows or control marrows, and HR-1 infection did not confer serum independence. These data show successful retroviral infection of normal bone marrow progenitor cells and suggest that expression of mutant H12-ras in such cells results in enhanced proliferation of early myeloid cells at the expense of differentiation.

Animals↗
PubMed1993

Synthesis of the K5 (group II) capsular polysaccharide in transport-deficient recombinant Escherichia coli.

The genes directing the expression of group II capsules in Escherichia coli are organized into three regions. The central region 2 is type specific and thought to determine the synthesis of the respective polysaccharide, whilst the flanking regions 1 and 3 are common to all group II gene clusters and direct the surface expression of the capsular polysaccharide. In this communication we analyze the involvement of region 1 and 3 genes in the synthesis of the capsular KS polysaccharide. Recombinant E. coli strains harboring all KS specific region 2 genes and having various combinations of region 1 and 3 genes were studied using immunoelectron microscopy. Membranes from these bacteria were incubated with UDP[14C]GlcA and UDPGlcNAc in the absence or presence of KS polysaccharide as an exogenous acceptor. It was found that recombinant strains with only gene region 2 did not produce the K5 polysaccharide. Membranes of such strains did not synthesize the polymer and did not elongate K5 polysaccharide added as an exogenous acceptor. An involvement of genes from region 1 (notably kpsC and kpsS) and from region 3 (notably kpsT) in the K5 polysaccharide synthesis was apparent and is discussed.

Antigens, Bacterial↗
PubMed1993

Why have child pedestrian death rates fallen?

Pedestrian injuries are a leading cause of childhood mortality and disability. Over the past two decades in Britain child pedestrian death rates have fallen despite large increases in traffic volume. In this paper Roberts examines the likely reasons for this decline. He argues that neither prevention programmes nor improvements in medical care are a plausible explanation and that the decline is most likely the result of a substantial reduction in children's traffic exposure. He believes, however, that restricting children's traffic exposure exacerbates socioeconomic differentials in childhood mortality and denies children their right to mobility. Roberts is convinced that one answer is for British transport policy to be aimed at providing mobility equitably rather than struggling to meet the ever increasing demands of car travel.

Accident Prevention↗
PubMed1993

Cerebral hemodynamics during cardiopulmonary bypass in children using near-infrared spectroscopy.

We describe a new noninvasive method using near-infrared spectroscopy for monitoring cerebral hemodynamics during cardiopulmonary bypass in children. All patients were undergoing open heart operations for repair of congenital heart defects. Standardized anesthesia, an alpha-stat method of blood gas management, and nonpulsatile flow were used in all cases. All measurements during bypass were made after steady-state conditions had been reached. Cerebral blood flow was measured on 13 occasions in 4 children, aged between 4 and 10 months (median, 5 months). Values of 15.9 to 53.5 mL x 100 g-1 x min-1 were obtained. Cerebral blood volume was measured in 1 patient, aged 4 months. Volumes of 4.3 to 8.0 mL x 100 g-1 were obtained on bypass at full pump flow (2.4 L.min-1 x m-2). On bypass at half flow, the volume increased to 14.7 mL x 100 g-1. Change in cerebral blood volume with changing carbon dioxide tension (CBVR) was measured in 13 patients aged from 1 to 90 months (median, 13.5 months). Preoperatively, CBVR was 0.12 +/- 0.07 mL x 100 g-1 x kPa-1 and was independent of mean arterial pressure, which remained between 40 and 80 mm Hg in all cases. During hypothermic bypass (25 degrees C), CBVR was significantly reduced to 0.05 +/- 0.02 mL x 100 g-1 x kPa-1. In addition, there were three values at mean arterial pressure of lower than 40 mm Hg in which CBVR was negative (-0.04 +/- 0.01 mL x 100 g-1 x kPa-1). We conclude that near-infrared spectroscopy is useful for the noninvasive investigation of cerebral hemodynamics during cardiopulmonary bypass.

Carbon Dioxide↗