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Biomedical subjects

M Harper

Publications and source records attributed to M Harper.

82 records · Page 5Linked to original sources

Identifying the determinants of tuberculosis control in resource-poor countries: insights from a qualitative study in The Gambia.

Despite the availability of effective treatment, tuberculosis (TB) remains a major cause of death from an infectious disease in the world, particularly in resource-poor countries. Among the chief reasons for this are deficiencies in case tracing and in adherence to treatment. In order to investigate the contribution of non-biological factors to these deficiencies, we carried out a qualitative study in The Gambia, West Africa, from October 2000 to March 2001. The methods used were focus group discussions, interviews, participant and non-participant observation, and case histories. Four domains were distinctively investigated: the TB patients, the community, the health care providers (including programme staff), and the donors and policy makers. Analysis of the data from all these sources indicated the contribution of a wide range of socio-anthropological factors which influence the success or otherwise of the TB control programme in The Gambia, i.e. gender, urban/rural residence, recourse to traditional healers, adherence to national health policies, knowledge about TB, migration, and socio-economic factors. It is concluded that all these factors must be taken into account in formulating interventions to improve detection of TB cases and patient adherence to treatment within the framework of the national TB control programmes, and proposals have been made for targeted interventions.

Allied Health Personnel↗

X-ray diffraction studies of an anti-azophenylarsonate antibody and of an antigen-antibody complex.

X-ray crystallographic studies of the Fab fragments of two murine monoclonal antibodies of predefined specificity are under way. Diffracted X-ray intensities of the crystalline native Fab fragment of an anti-azophenylarsonate antibody and of three heavy atom derivatives have been measured to a resolution of 3.5 A. A preliminary 6-A resolution electron density map has been obtained. The 6-A resolution structure of an antigen-antibody (hen lysozyme-Fab) complex has been determined. There are close contacts between the antigen and the antibody over a large contact area, about 20 X 25 A. At least two segments of the polypeptide chain of lysozyme, of about 10 amino acids each (positions 19-27 and 116-129), are involved in the contacts, as well as all six complementarity-determining regions of the antibody. No gross conformational changes are observed in the antigen at this resolution, although there are some smaller local changes in areas in contact with the antibody and elsewhere. The effects of amino acid substitutions on antigen recognition by the monoclonal anti-hen lysozyme antibody were investigated using different, closely related lysozymes. These effects can be readily explained in terms of the three-dimensional model presented here. A 3.5-A resolution electron density map has been calculated and is currently under study.

Animals↗

Decreasing seroprevalence of human immunodeficiency virus type 1 in a regional blood donor population.

Blood banks have intensified their efforts to discourage donations from individuals at risk for the human immunodeficiency virus (HIV-1). Since the onset of HIV-1 donor screening in April 1985, a marked reduction in seroprevalence has been seen at the authors' institutions: from 51 cases per 100,000 donors in 1985 to 13 per 100,000 in the first 6 months of 1988. Data from 3.5 years have been analyzed for temporal trends in the association of HIV-1 seroprevalence with donation site (urban vs. non-urban) and donor gender. The association of HIV-1 seropositivity with an urban donation site decreased through 1987 as the urban-to-nonurban donation odds ratio declined from 6.48 in 1985 to 2.54 in 1987. Despite this decrease, both men and women who donated in urban areas had a significantly higher seroprevalence than those in nonurban areas. Male donors had a higher overall HIV-1 seroprevalence than female donors. However, the male-to-female odds ratio declined from 2.94 in 1985 to 1.96 in 1988, and male gender was no longer significantly associated with HIV-1 seropositivity. This change in the donor profile appears to reflect declining numbers of seropositive men who acknowledge risk factors and greater numbers of women with no identified risks for HIV-1. This study documents a dramatic decrease in HIV-1-seropositive donors and suggests that the deferral of high-risk individuals has become increasingly successful.

Blood Donors↗

A comparison of the efficiency of three anesthesia circle systems.

Three commonly employed anesthesia circle systems were tested to determine what effect the placement of the inflow port, overflow valve, and inspiratory and expiratory valves, as well as inflow rate, had on the rate of rise of anesthetizing alveolar concentrations of halothane. System efficiency was evaluated on the basis of whether alveolar gases, containing low concentrations of halothane, or fresh and deadspace gases, containing higher concentrations of halothane, were eliminated through the overflow valve. Small potentially significant differences in efficiency were found: greatest efficiency (greatest ejection of alveolar gas) occurred when inspiratory and expiratory valves were close to the endotracheal tube and the overflow valve was immediately distal to the expiratory valve. Increasing inflow rate from 1 to 3 L/min had a large impact on the rate of rise of alveolar halothane concentration. A further increase to 5 L/min had a relatively small effect.

Anesthesia, Inhalation↗

Latching on.

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Adult↗