Search PubMed⌕ Search

Biomedical subjects

B Evans

Publications and source records attributed to B Evans.

At least 37 records · Page 2Linked to original sources
PubMed2001

Assessing the impact of national anti-HIV sexual health campaigns: trends in the transmission of HIV and other sexually transmitted infections in England.

OBJECTIVE: To assess the impact of the sexual component of AIDS and HIV campaigns on transmission of HIV and other sexually transmitted infections (STIs). DESIGN: Comparison of time series data. SETTING: England, 1971-1999. OUTCOME MEASURES: HIV transmission and diagnoses among men who have sex with men (MSMs), rates of attendances and specific STI diagnoses (per 100 000 total population) at genitourinary medicine (GUM) clinics. RESULTS: Awareness of AIDS and campaigns in 1983-4 among homosexual men coincided with substantial declines in transmission of HIV and diagnoses of syphilis among MSMs. During general population campaigns in 1986-7 new GUM clinic attendances requiring treatment fell by 117/10(5) in men and 42/10(5) in women. Rates for gonorrhoea fell by 81/10(5) and 43/10(5) and genital herpes by 6/10(5) and 4/10(5), respectively. Previous rises in genital wart rates were interrupted, while rates of attendances not requiring treatment (the "worried well") increased by 47/10(5) and 58/10(5) for men and women, respectively. Since 1987 diagnoses of HIV among MSMs have not declined, averaging 1300-1400 annually. Following a period of unchanging rates there have been substantial increases in GUM attendances requiring treatment, notably for gonorrhoea, syphilis, and viral STIs since 1995. CONCLUSIONS: Self help initiatives and awareness among homosexual men in 1983-4 contributed significantly to a fall in HIV transmission among MSMs, and the general campaigns of 1986-7 were associated with similar effects on all STI transmission. Both effects seem to have occurred through changing sexual behaviour, and probably contributed to the UK's low national HIV prevalence. Bacterial STI incidence has increased significantly since 1995 and there is no evidence that recent prevention initiatives have reduced HIV transmission among MSMs, hence sexual health initiatives need to be comprehensively reinvigorated in England.

Condylomata Acuminata↗
PubMed2001

An exploration of the effects of weighted garments on balance and gait of stroke patients with residual disability.

OBJECTIVE: To explore the effects of weighted garments on the balance and gait of stroke patients. DESIGN: A pilot randomized controlled study with blinded measurement. SETTING: Weighted garments were worn by patients living in the community and measurement was made in a hospital-based gait laboratory. SUBJECTS: Twenty-four adults who were at least six months post stroke and were able to walk 10 metres with or without assistance or a walking aid. INTERVENTION: The six-week treatment-phase subjects were given a set of weighted garments which they were shown how to apply and instructed to wear on their paretic side. Subjects randomly allocated to the six-week control phase were not given any weighted garments. MAIN OUTCOME MEASURES: Balance was measured with the Berg Balance Scale. Gait was measured using GaitMat II, an instrumented walkway. Gait parameters of interest were velocity and symmetry of: step length; single support time; double support time; and support base width. Measures were made at baseline before randomization (baseline) and at the end of the six weeks of intervention (outcome). RESULTS: No statistically significant differences were found between the treatment and control groups at outcome for balance (Mann-Whitney U-test; p = 0.74), gait velocity (p = 0.68) or symmetry of gait parameters (p = 0.33 to p = 0.75). CONCLUSIONS: We found no evidence to support the clinical use of these weighted garments for stroke survivors.

Activities of Daily Living↗
PubMed2000

Variable absorption of carbidopa affects both peripheral and central levodopa metabolism.

Carbidopa (CD), a competitive inhibitor of aromatic l-amino acid decarboxylase that does not cross the blood-brain barrier, is routinely administered with levodopa (LD) to patients with Parkinson disease (PD) to reduce the peripheral decarboxylation of LD to dopamine. Using a stable isotope-labeled form of LD, the authors examined in 9 PD patients the effects of variable CD absorption on peripheral and central LD metabolism. Subjects were administered orally 50 mg of CD followed in 1 hour by a slow bolus intravenous infusion of 150 mg stable isotope-labeled LD (ring 1',2',3',4',5',6'-13C). Eight patients underwent a lumbar puncture 6 hours following the infusion. Blood and cerebrospinal fluid (CSF) samples were analyzed for labeled and unlabeled metabolites using a combination of high-performance liquid chromatography and mass spectrometry. When patients were divided into "slow" and "rapid" CD absorption groups, significantly greater peripheral LD decarboxylation (as measured by area under the curve [AUC]-labeled serum HVA) was noted in the poor absorbers (p = 0.05, Mann-Whitney U test). Elimination half-lives for serum LD did not differ between groups, suggesting a further capacity for decarboxylation inhibition in the "rapid" absorbers. A significant correlation between AUC serum CD and percent-labeled HVA in CSF was found for all patients (R = 0.786, p = 0.02). "Rapid" as compared to "slow" CD absorbers had significantly more percent-labeled CSF HVA (60 vs. 49, p = 0.02, Mann-Whitney U test), indicating greater central-labeled DA production in the better CD absorbers. The data suggest that peripheral aromatic l-amino acid decarboxylase activity is not saturated at CD doses used in current practice. The authors believe that future studies to better examine a dose dependence of CD on peripheral LD decarboxylation and LD brain uptake are warranted.

Absorption↗
PubMed2000

National assessment of prevalent diagnosed HIV infections.

HIV infection is associated with high treatment and care costs and subject to large differences in prevalence between health districts. Equitable distribution of resources requires information provided by an annual national survey of prevalent diagnosed HIV infections (SOPHID). This measures HIV caseloads by health district of residence throughout England, Wales, and Northern Ireland and is used to inform local public health professionals and to improve allocation of government funding for HIV prevention and care. Survey totals are adjusted by underreporting and non-attendance factors to produce a more accurate assessment of the total caseloads. On average the combined adjustments increase the reported caseload by 14.7% annually. Adjusted prevalence estimates ranged from 14,164 in 1995 to 18,460 in 1998, an increase of 30%.

CD4 Lymphocyte Count↗
PubMed1999

Mortality in young adults in England and Wales: the impact of the HIV epidemic.

OBJECTIVE: To quantify the contribution of the HIV epidemic to premature mortality in England and Wales 1985-1996. DESIGN: Surveillance of deaths in HIV-infected individuals and causes of death from death certificates. MAIN OUTCOME MEASURES: Time trends in age-specific mortality rates among 15-44 year olds and years of potential life lost (YPLL) to age 65 associated with HIV infection and other important causes of death in young adults. RESULTS: The crude age-specific mortality rates for all causes of death in the 15-44 year age band remained fairly constant between 1985 and 1996: in other age bands a decrease was seen. Deaths from both suicide and HIV increased in men aged 15-44 years. Although suicide accounted for a greater number of deaths throughout the period investigated, the largest proportional and absolute increase was seen for deaths in HIV-infected people. By 1996, the contribution of HIV to YPLL to age 65 varied from less than 0.5% in most rural localities to 20% of total YPLL in one London health authority. CONCLUSIONS: While part of the adverse trend in mortality in younger adults since 1985 was attributable to suicide, most resulted from HIV infection. The impact of HIV infection on mortality was greatest in London.

Adolescent↗
PubMed1999

Explaining community-level variance in group randomized trials.

Between-community variance or community-by-time variance is one of the key factors driving the cost of conducting group randomized trials, which are often very expensive. We investigated empirically whether between-community variance could be reduced by controlling individual- and/or community-level covariates and identified these covariates from four large community-based group randomized trials or surveys: the Working Well Trial; Kaiser Adolescent Survey; Kaiser Adults Survey; and the Eating Patterns Study. We found that adjusting for covariates will often substantially reduce the between-community variance component. Therefore investigators could block the communities according to these covariates, or adjust for these covariates to improve the power of community trials. We found that the community-by-time variance components are always near zero in these data sets, especially for the surveys where a cohort was followed over time. The covariate adjustment had less impact on reducing the community-by-time variance for the cohort samples than for the cross-sectional samples. This suggests that blocking may not be necessary for the design of the group randomized trials where the change from baseline is of primary interest. The Working Well Trial data were used to illustrate this point.

Adolescent↗
PubMed1999

An early developmental role for eph-ephrin interaction during vertebrate gastrulation.

Eph receptor tyrosine kinases (RTK) and their ephrin ligands are involved in the transmission of signals which regulate cytoskeletal organisation and cell migration, and are expressed in spatially restricted patterns at discrete phases during embryogenesis. Loss of function mutants of Eph RTK or ephrin genes result in defects in neuronal pathfinding or cell migration. In this report we show that soluble forms of human EphA3 and ephrin-A5, acting as dominant negative inhibitors, interfere with early events in zebrafish embryogenesis. Exogenous expression of both proteins results in dose-dependent defects in somite development and organisation of the midbrain-hindbrain boundary and hindbrain. The nature of the defects as well as the distribution and timing of expression of endogenous ligands/receptors for both proteins suggest that Eph-ephrin interaction is required for the organisation of embryonic structures by coordinating the cellular movements of convergence during gastrulation.

Animals↗
PubMed1999

A new approach to vision screening in schools.

PURPOSE: To determine the prevalence of visual "defects" among a sample of young schoolchildren and evaluate a new system for vision screening in schools. METHODS: A new system for vision screening in schools has been developed. The system is based on a computer program which may be run on a low specification personal computer. Information about the child's symptoms, history and family history is acquired by means of a parental questionnaire and entered into the program prior to the vision screening. Distance visual acuity and stereopsis are measured directly on the computer screen and colour vision is assessed using a reduced Ishihara test. The program carries out an "expert" analysis of the questionnaire data and the vision test results and determines the most likely diagnosis. Reports for parents, teachers, optometrists, doctors can be generated automatically and statistics relating to the overall screening program are available. An evaluation of a prototype version of the system was carried out on 245 schoolchildren aged between 5 and 8 years. RESULTS: Overall, 48 children failed the screening (excluding colour vision deficiencies), 32 of whom were unaware of any problem with their eyes. Comparison of the result of the vision screening with the outcome of a full eye examination gave a sensitivity of 93.8% and a specificity of 96.1%. CONCLUSION: A significant number of young school children have unsuspected remediable visual defects. The computer-based vision screener provides an efficient, sensitive and specific method for screening in schools.

Child↗
PubMed1999

Bacterial vaginosis in lesbians: evidence for lack of sexual transmission.

The effect of non-heterosexual factors on the vaginal flora has been studied. Ninety-one lesbians attending a specialist genitourinary medicine service for lesbians were studied. Bacterial vaginosis (BV) was diagnosed in 51.6% of them. While most of the women had previously had a male sexual partner, the presence of BV was not associated with a male sexual partner in the previous 12 months. A detailed analysis of lesbian sexual practices in the group did not relate BV to any sexual practice which would have the propensity to pass vaginal secretions from one to the other.

Female↗
PubMed1998

The embryogenesis of rod photoreceptors in the teleost fish retina, Haplochromis burtoni.

Development of the retina, like that of other tissues, occurs via an orderly sequence of cell division and differentiation, producing the functional retina. In teleost fish, however, cell division and differentiation in the retina continue throughout the life of the animal in two distinct ways. Stem cells in a circumferential germinal zone at the periphery of the retina give rise to all retinal cell types and progenitor cells located throughout the retina in the outer nuclear layer (ONL) produce new rod photoreceptors. These processes in adult retina recapitulate in space the embryonic events responsible for forming the retina. Analysis of these events in an African cichlid fish, Haplochromis burtoni, confirmed that cone photoreceptors differentiate first, followed by rod photoreceptors. Correspondingly, at the margin of the eye, cone photoreceptors differentiate nearer to the margin than do rods. Control of photoreceptor production is not understood. Here we present the time of appearance and distribution pattern of GABA and vimentin which are candidates for the control of retinal cell division and differentiation. Antibody staining reveals that both GABA and vimentin exhibit unique patterns of expression during embryonic retinal development. Vimentin immunoreactivity is evident throughout the retina in a spoke-like pattern between developmental Days 4 and 7, as both cone and rod photoreceptors are being formed. GABA is expressed in horizontal cells between Days 5 and 7, corresponding to the onset of rod differentiation in time and in position within the retina. Moreover, the wave of GABAergic staining in the horizontal cells parallels the wave of rod differentiation across the embryonic retina of H. burtoni. Thus, GABA may play a role in the development of rod photoreceptors.

Animals↗