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Biomedical subjects

L London

Publications and source records attributed to L London.

78 records · Page 5Linked to original sources
PubMed1985

Phenotypic characteristics of human natural killer cells.

Surface antigen analysis of human natural killer (NK) cells using anti-lymphocyte monoclonal antibodies identifies NK cells as a discrete cell type (average 15% of peripheral blood lymphocytes) distinct from T, B, and myelomonocytic cells. Virtually all NK cells bear low-affinity Fc receptors for IgG, as detected by antibody B73.1 and N901 antigen; 80-90% of NK cells express the E receptor (OKT11), the C3bi receptor (OKM1), and the T10 antigen; 30-50% are T8 (+), and 30-70% are Leu7 (+). This phenotype is maintained on NK cell-derived clones and on activated NK cells, which are induced to express interleukin 2 receptor (Tac antigen), transferrin receptor, HLA-DR, and several T cell activation antigens but not, like resting NK cells, antigens (T1, T3, T4) characteristic of T cells. On the contrary, NK cell-derived leukemias may express T1 or, more frequently, T3 antigens.

Antigens, Surface↗
PubMed1985

Induction of proliferation in vitro of resting human natural killer cells: expression of surface activation antigens.

In this report, we show that resting human peripheral blood NK cells, positively enriched with antibody B73.1, can be induced to proliferate in vitro in short-term cultures, and newly express membrane activation antigens. B73.1+ NK cells, cultured for 6 days in the presence of conditioned medium containing IL 2 and irradiated B lymphoblastoid cells, show significant [3H]TdR incorporation beginning on day 4. At that time, a large proportion of the cells express HLA-DR and 4F2 antigens, and transferrin and IL 2 receptors, all detectable at high density by indirect immunofluorescence with the use of monoclonal antibodies. These cells maintain their ability to lyse target cells spontaneously or in the presence of antibodies. By two-color immunofluorescence and cell cycle analysis combined with indirect immunofluorescence, we demonstrate directly that the activation antigens are expressed on all NK (B73.1+) cells in the S/G2/M phases of the cell cycle, and on only a proportion of those in the G0/G1 phases.

Animals↗
PubMed1984

Response of resting human peripheral blood natural killer cells to interleukin 2.

The present study shows that recombinant interleukin 2 (IL-2) purified to homogeneity induces a rapid and potent enhancement of spontaneous cytotoxicity of human peripheral blood lymphocytes. The cells mediating cytotoxicity after 18-h treatment with IL-2 have surface markers of natural killer (NK) cells and are generated from the peripheral blood subset containing spontaneous cytotoxic cells. A parallel production of gamma interferon (IFN-gamma) is induced by recombinant IL-2 (rIL-2), and NK cells appear to be the major producer cells, whereas T cells are unable to produce IFN-gamma under these experimental conditions. However, the kinetics of the enhancement of cytotoxicity are faster than those of IFN-gamma production, and monoclonal anti-IFN-gamma antibodies do not suppress this effect, making it unlikely that the IFN-gamma produced is responsible for the enhancement. The enhancement of NK cell activity induced by rIL-2 precedes any proliferative response of the lymphocytes, which is instead observed in longer-term cultures of both NK and T cells.

Adjuvants, Immunologic↗
PubMedDate not supplied

Learning from our apartheid past: human rights challenges for health professionals in contemporary South Africa.

Central to South Africa's democratic transformation have been attempts to understand how and why human rights abuses were common under apartheid. In testimony to the Truth and Reconciliation Commission evidence has emerged of a wide range of past complicity in human rights abuses by health professionals and their organisations. This has presented a major challenge to the health sector to develop ways to operationalize a commitment to human rights in the future. This paper argues that only after a process of self-reflection, both personal and institutional, which enables a thorough and accurate analysis of why things went so wrong, can the health sector effectively move forward. The authors' perspective draws on the submission to the TRC Health Sector Hearings by the Health and Human Rights Project in 1997, which provides a systemic and case-based analysis of the health sector's role in human rights abuses under apartheid. However, human rights responses have to take account of a changing national and global terrain in which human rights issues are no longer as morally absolute as previously encountered, and in which seemingly insuperable resource constraints, inimical economic policies, and the demobilization of civil society, are serious obstacles. Moreover, the politics of transformation has generated expediencies that threaten to rewrite history in ways that fundamentally cheapen human rights. To address this contradiction, the authors propose a set of objectives that places accountability of health professionals in a human rights framework. These objectives are intended to give substance to the main tasks facing the health sector--to develop and infuse the capacity to recognise and integrate both the 'new' and traditional human rights dilemmas, and to effect personal and institutional transformation. A matrix is presented, linking these objectives to key role players in the health sector and identifying activities specific for each role player. As the health sector in South Africa grapples with the challenges framed in this model, key lessons for the international community may emerge that further our understanding of the complex relationship between health and human rights and how best to implement strategies for the attainment of human rights in health.

Black or African American↗
PubMedDate not supplied

Occupational epidemiology in agriculture: a case study in the southern African context.

Some challenges facing occupational epidemiology in developing countries are outlined in this case study of agriculture drawing on Southern African research. These include the characterization of exposures in resource- and data-poor environments typical of developing countries, the assessment of outcomes where cross-cultural and socio-environmental confounders may be substantial obstacles, and the impact of environmental exposures on workplace health. Traditional assignment of low priority to the chronic effects of low-dose exposures relative to acute morbidity in developing countries must be critically examined, as must the gender bias of much occupational epidemiology in agriculture. Advocacy issues involving child labor and the ethics of research among vulnerable groups deserve rigorous attention. It is argued that, if occupational epidemiology is to have meaningful impact on the health of the most marginalized groups of workers in developing countries, it must redefine itself in terms of a public health approach. The boundaries of epidemiologic inquiry need to be broad, and amenable to interfacing with policy research, using qualitative methods and participatory approaches. More so than in order industrial settings, epidemiologists must move from research to practice, seeking to take action where interventions are needed, and to evaluate such actions.

Adolescent↗