Biomedical subjects

Laura Johnson

Publications and source records attributed to Laura Johnson.

9 recordsLinked to original sources

PubMed2006

Personal involvement of young people in HIV prevention campaign messages: the role of message format, culture, and gender.

To examine young people's reactions to and understanding of HIV prevention messages developed for MTV's global HIV prevention campaign Staying Alive, videotaped campaign materials were shown to focus group discussion (FGD) participants living in urban areas of Brazil, Kenya, Nepal, and Senegal. Responses related to "personal involvement" with the message were identified in the data from these FGDs and were examined in relationship to the emerging message themes, the message format (public service announcements [PSAs] vs. documentary), cultural context (site), and participant gender. Across groups, greater personal involvement (measured by personal connections, emotional reactions, and lessons learned) was found in responses about the documentary format compared to the PSA format. Exceptions were found for specific PSAs that were considered more relevant within specific gender or cultural contexts. Implications of findings for global campaigns were considered.

Adolescent↗

PubMed2006

On the utility of data from the International HapMap Project for Australian association studies.

We compare patterns of linkage disequilibrium (LD) for 633 SNPs in two regions between samples collected in two Australian states and HapMap samples collected from Utah residents of Northern and Western (NW) European ancestry (CEU). Patterns of LD in the Australian and HapMap samples are similar, and tag SNPs chosen using HapMap genotypes perform almost as well on Australian samples as tags chosen using Australian genotypes.

Europe↗

PubMed2006

The value of contraception to prevent perinatal HIV transmission.

OBJECTIVE: The objective of this study was to highlight the value of preventing unintended pregnancies among HIV-infected women as a strategy to prevent perinatal HIV transmission. GOAL: The goal of this study was to assess the cost-effectiveness of family planning programs to avert HIV-positive births with the current programmatic emphasis: prenatal care services that provide and promote nevirapine for prevention of mother-to-child transmission of HIV. STUDY DESIGN: Cost-effectiveness analyses were conducted from the health system perspective during 1 year with a hypothetical sub-Saharan African population. Expected program costs were combined with number of HIV-positive births averted for each strategy. RESULTS: At the same level of expenditure, the contraceptive strategy averts 28.6% more HIV-positive births than nevirapine for prevention of mother-to-child transmission of HIV. CONCLUSIONS: Increasing contraceptive use among nonusers of contraception who do not want to get pregnant is cost-effective and is an equally important strategy to prevent perinatal transmission as prenatal care programs that provide and promote nevirapine to HIV-infected mothers.

Adolescent↗

PubMed2006

Cervical spine injury is highly dependent on the mechanism of injury following blunt and penetrating assault.

BACKGROUND: The mechanism of injury has not been highly regarded as an important variable when evaluating cervical spine injuries. The aim of this study was to determine the incidence of cervical spine fracture (CSF) and cervical spinal cord injury (CSCI) based on mechanism following blunt and penetrating assault to better aid prioritization of management. METHODS: Retrospective analysis from two large urban Level I trauma centers over 87 and 144 months caused by gunshot wounds (GSW), stab wounds (SW) or blunt assault (BA). RESULTS: During the study period, there were 57,532 trauma patients evaluated at the two trauma centers, of which 42.3% were following blunt or penetrating assault. The rates of CSF and CSCI for the various mechanisms were similar between the two centers. The rates for having CSF were significantly different (p < 0.05) for the various mechanisms. GSW (1.35%) was the highest followed by BA (0.41%) and then SW (0.12%). The rates of CSCI for GSW (0.94%) were significantly (p < 0.05) higher than BA (0.14%) and SW (0.11%). For GSW patients, all patients with CSF or CSCI had a point of entry between the ears and the nipple. For SW patients, the wound was directly in the neck below the mandible and above the trapezius muscle. Although many of the SW patients also suffered blunt assault, none of the CSF or CSCI injuries were from blunt forces. In addition, all patients, both blunt and penetrating who had CSCI had neurologic deficit at the time of presentation. Surgical stabilization or tongs were applied in 15.5% (26 of 168) of the GSWs, 27.8% (3 of 11) of the SWs and 31.6% (6 of 19) of the BA patients. There was a BA patient (1 of 4,390) patient with CSF that was neurologically intact that required surgical stabilization and this patient had neck pain on admission. No penetrating injury patients with CSCI regained significant neurologic recovery during the hospitalization. SUMMARY: The rate of CSF or CSCI is low following assault and dependent on mechanism of injury. Thus the concern and extent of evaluation should also be dependent on the mechanism of injury. Neurologic deficits from penetrating assault were established and final at the time of presentation. Concern for protecting the neck should not hinder the evaluation process or life saving procedures.

Adult↗

PubMed2005

Behavioural determinants of obesity.

Obesity in children arises from a complex interplay between genetic susceptibility and behaviour, primarily relating to dietary habits and physical activity. Evidence for specific behavioural factors that promote or protect against excess weight gain in children is more limited than in adults, and the effects of growth and development are not clear. A number of behavioural risk factors has been postulated, including diets with a high energy density, high consumption of sugar-sweetened beverages, large portion sizes, eating patterns, high levels of sedentary behaviour and low levels of physical activity. However, most evidence is derived from cross-sectional studies which frequently yield conflicting results. More prospective studies with accurate measures of exposures and outcomes in terms of body composition are needed to provide more robust evidence on which to base interventions to achieve long-term behavioural change and prevent excess weight gains in children.

Carbonated Beverages↗

PubMed2005

Fear, hope and social desirability bias among women at high risk for HIV in West Africa.

BACKGROUND: Self-reports are widely used for measuring behaviour in HIV research and prevention, yet the accuracy of these measures has been shown to be questionable in many cases. Social desirability bias (SDB) is one of the key factors identified as affecting self-report accuracy. METHODS: Using in-depth interviews, we examined SDB from the perspective of 60 women at high risk for HIV in two West African countries: Ghana and Nigeria. We solicited suggestions for reducing SDB in the context of HIV research and prevention, and asked for feedback regarding methods currently being employed to reduce SDB. RESULTS: Themes pertaining to fear and a desire to have a better life were pervasive throughout the data. Thematic structure was similar between sites and age groups, although younger women tended to be more concerned about the interview context. CONCLUSIONS: Vulnerability of a population should be considered when asking sensitive questions. Audio-computer-assisted self-interviews may not be appropriate for vulnerable populations in developing countries, particularly for older respondents.

Adult↗

PubMed2005

Multiple sclerosis: a haplotype association study.

Results are presented from a genomewide haplotype association study on multiple sclerosis (MS) cases from Tasmania, an island state of Australia. Cases were ascertained on strict clinical and radiological grounds and on the fact that they had at least one grandparent born in the state. This enriched for early settler chromosomes among present day Tasmanians with MS and increased the chances of finding common haplotype sharing at disease predisposition loci in distant relatives sharing common ancestral haplotypes. Four-to-five close relatives were also collected for each of 170 cases and 105 population-based controls. All were genotyped at a 5cM resolution, haplotypes reconstructed and sharing estimated using an empirical approach based on sorting haplotypes to find the most common at each locus and then generating a test statistic for excess sharing in the cases based on permutation testing. Five initial loci were found where there was an excess sharing in the cases. These were fine-mapped with 10-12 additional markers. Only loci on chromosomes 6 and 10 remained after fine mapping. These loci demonstrate an increase in sharing of multi-marker haplotypes in MS cases compared to both population control transmitted haplotypes and case non-transmitted haplotypes.

Haplotypes↗

PubMed2004

Extended haplotype analysis in the HLA complex reveals an increased frequency of the HFE-C282Y mutation in individuals with multiple sclerosis.

In order to resolve a multiple sclerosis (MS) susceptibility locus that we had identified in earlier work at the telomeric end of the HLA complex, we genotyped another 34 microsatellite markers (47 in total) across the class I/extended class I region in 166 Tasmanian MS case and 104 control families (D6S299-D6S265). Extended MS susceptibility haplotypes, up to 9 Mb in length, were observed in 11% of MS cases and 4% of controls. Direct comparison of the telomerically extended portion of the MS susceptibility haplotype in HFE-Cys282Tyr (C282Y)-homozygous haemochromatosis patients identified a common ancestry for this genomic segment, which translated into an increased frequency of the C282Y allele in 489 MS cases from Tasmania and Victoria (10.2%) compared with controls (6.7%). Six C282Y homozygotes (1.2%), a three-fold increased rate over the general population, and 88 heterozygotes (18%) were identified. One C282Y-homozygous female was identified who had MS and was being treated for symptoms of iron overload. Interestingly, for 71 Victorian MS cases not of north western European (NWE) ancestry, a DR15-independent reduction in the frequency of the C282Y allele was observed, supporting the theory of a NWE origin for the C282Y-variant of the DR15 ancestral haplotype (C282Y-HLA-A*0301-B*0702-DRB1*1501-DQB1*0602). The results of linkage disequilibrium (LD) and log linear modelling analyses suggest that C282Y is increased in MS cases of NWE ancestry because it is in LD with the ancestral DR15 susceptibility haplotype (7.1) and that it does not play an independent role in predisposition to MS. However, our findings provide the impetus for further investigations into the role of iron metabolism in the severity of MS.

DNA Primers↗

PubMed2003

Respondent perspectives on self-report measures of condom use.

There is much concern about the validity of self-reported condom use. In an effort to improve self-report measures, a study using semistructured interviews was conducted to elicit the perspectives of women who had participated in a microbicide clinical trial in which self-reports of condom use were included. Women were asked about their comprehension of the questions, how they remembered their condom use and their sensitivity to the expectations of the interviewer, and how this affected their answers. Although most women believed they were accurate in their answers about condom use, a number of women admitted to exaggerating their condom use or believed other women did, citing concerns related to interviewers' expectations of them as the primary reason. Most women did not believe that comprehension or memory was a problem and a number were able to articulate strategies for remembering their condom use.

Adolescent↗