Lundy Braun

Race, Ethnicity, and Health: Can genetics explain disparities?

Over the past decade, numerous studies have documented profound racial and ethnic disparities in disease in the United States. This essay examines how popular and scientific concepts of race and ethnicity converge with dominant understandings of genetics to inform the design and interpretation of research, public health policy, and medical practice. Although there is some acknowledgment in the biomedical community that racial and ethnic categories are social and not genetic, ideas about race and ethnicity that circulate in biomedicine are contradictory. Thus, in practice genetic explanations for observed differences are common both in the scientific literature and in popular media accounts of biomedical research. Such explanations naturalize racial and ethnic difference and create a conceptual barrier to developing a research program that explores the complex ways in which social inequality and experiences of racial discrimination interact with human biology to influence patterns of disease. Importantly, genetically based ideas lead to disease prevention policies that are bound to be ineffective.

Purification and Culture of Oval Cells from Rat Liver

Publisher Summary This chapter discusses the purification and culture of oval cells from rat liver. Oval cells are liver epithelial cells that proliferate during the early stages of hepatocarcinogenesis induced by many chemicals. The biological importance of oval cells derives from two observations: (1) in azo dye carcinogenesis, oval cells give rise to hepatocytes and to transitional cells, which combine morphological features of these two cell types, and at the early stages of hepatocarcinogenesis induced not only by azo dyes but also by other carcinogens, oval or transitional cells contain many of the markers associated with hepatic neoplasia. An important step in the assessment of the biological properties of oval cells was the identification of AFP in oval and/or transitional cells at the early stages of carcinogenesis and the conclusion that the rapid increase in serum AFP detected a few days or weeks after the administration of many carcinogens is due to the proliferation of oval cells. In the early stages of carcinogenesis, the proliferation of duct cells, transitional cells, or small hepatocytes takes place and these cell types form a conspicuous but heterogeneous oval cell compartment where duct cells most likely predominate. Transitional cells may mature into new diploid hepatocytes, which have been detected in hepatocarcinogenesis induced by ethionine and other chemicals. Such diploid hepatocytes or the transitional cells might be the populations from which liver tumors may develop several months later. Most aspects of this working hypothesis are testable experimentally and some of the work on the isolation and characterization of oval cells and the growth of oval cells in cultures leading to the formulation of the hypothesis.

TGF‐β in Liver Development, Regeneration, and Carcinogenesisa

TGF-Pl is a potent inhibitor of hepatocyte DNA replication in culture.l.2 This finding and the report.that a hepatocellular carcinoma cell line was not sensitive to DNA synthesis inhibition by TGF-P3 have led to a large number of studies to assess the role of E F I , in normal and neoplastic liver growth and in the development of hepatic fibrosis. Here we present some of our studies on TGF-p during fetal, regenerative, and neoplastic growth in rat liver.

Defining race/ethnicity and explaining difference in research studies on lung function

The 2005 guidelines of the American Thoracic Society/European Respiratory Society recommend the use of race- and/or ethnic-specific reference standards for spirometry. Yet definitions of the key variables of race and ethnicity vary worldwide. The purpose of this study was to determine whether researchers defined race and/or ethnicity in studies of lung function and how they explained any observed differences. Using the methodology of the systematic review, we searched PubMed in July 2008 and screened 10 471 titles and abstracts to identify potentially eligible articles that compared “white” to “other racial and ethnic groups”. Of the 226 eligible articles published between 1922 and 2008, race and/or ethnicity was defined in 17.3%, with the proportion increasing to 70% in the 2000s for those using parallel controls. Most articles (83.6%) reported that “other racial and ethnic groups” have a lower lung capacity compared to “white”; 94% of articles failed to examine socioeconomic status. In the 189 studies that reported lower lung function in “other racial and ethnic groups”, 21.8% and 29.4% of explanations cited inherent factors and anthropometric differences, respectively, whereas 23.1% of explanations cited environmental and social factors. Even though researchers sought to determine differences in lung function by race/ethnicity, they typically failed to define their terms and frequently assumed inherent (or genetic) differences.

Development and implementation of a science training course for breast cancer activists: Project LEAD (leadership, education and advocacy development)

Objective To develop and implement Project LEAD (leadership, education, and advocacy development), a science course for breast cancer activists.

Reifying Human Difference: The Debate on Genetics, Race, and Health

The causes of racial and ethnic inequalities in health and the most appropriate categories to use to address health inequality have been the subject of heated debate in recent years. At the same time, genetic explanations for racial disparities have figured prominently in the scientific and popular press since the announcement of the sequencing of the human genome. To understand how such explanations assumed prominence, this essay analyzes the circulation of ideas about race and genetics and the rhetorical strategies used by authors of key texts to shape the debate. The authority of genetic accounts for racial and ethnic difference in disease, the author argues, is rooted in a broad cultural faith in the promise of genetics to solve problems of human disease and the inner truth of human beings that is intertwined with historical meanings attached to race. Such accounts are problematic for a variety of reasons. Importantly, they produce, reify, and naturalize notions of racial difference, provide a scientific rationale for racially targeted medical care, and distract attention from research that probes the complex ways in which political, economic, social, and biological factors, especially those of inequality and racism, cause health disparities.

Asbestos-related disease in South Africa: the social production of an invisible epidemic.

South Africa was the third largest exporter of asbestos in the world for more than a century. As a consequence of particularly exploitative social conditions, former workers and residents of mining regions suffered--and continue to suffer--from a serious yet still largely undocumented burden of asbestos-related disease. This epidemic has been invisible both internationally and inside South Africa. We examined the work environment, labor policies, and occupational-health framework of the asbestos industry in South Africa during the 20th century. In a changing local context where the majority of workers were increasingly disenfranchised, unorganized, excluded from skilled work, and predominantly rural, mining operations of the asbestos industry not only exposed workers to high levels of asbestos but also contaminated the environment extensively.

Scientific controversy and asbestos: making disease invisible.

Abstract Despite irrefutable evidence that asbestos causes asbestosis, lung cancer, and mesothelioma, asbestos mining, milling, and manufacturing continue. The authors discuss three scientific debates over the roles of fiber types, viruses, and genetics in the development of mesothelioma. While these controversies might appear internal to science and unconnected to policies of the global asbestos industry, they argue that scientific debates, whether or not fostered by industry, playa central role in shaping conceptualization of the problem of asbestos-related disease. In South Africa, India, and elsewhere, these controversies help to make the disease experience of asbestos-exposed workers and people in asbestos-contaminated communities invisible, allowing the asbestos industry to escape accountability for its practices.

Molecular analysis of episomal human papillomavirus type 16 DNA in a cervical carcinoma cell line

Integration of human papillomavirus type 16 DNA sequences into host DNA is a frequent event in cervical carcinogenesis. However, recent studies showing that HPV16 is present exclusively in an episomal form in many primary cervical cancers suggest that HPV16 can transform target cells by mechanisms that do not require viral integration. We have established a cervical carcinoma cell line that harbors episomal copies of HPV16 DNA of approximately 10 kb. Restriction enzyme and two-dimensional gel analysis confirmed that HPV16 DNA was extrachromosomal with both monomeric and multimeric forms present. HPV16 was maintained as episomes with passage both in culture and after subcutaneous growth in nude mice. The 10 kb viral genome, consisting of a full-length copy of HPV16 and a partial duplication of the long control region and the L1 open reading frame, exhibited transforming activity comparable to prototype HPV16. This cell line should provide a useful model system for studying the biological significance of the physical state of the HPV16 genome in cervical carcinoma cells.

Race/Ethnicity in Medical Education: An Analysis of a Question Bank for Step 1 of the United States Medical Licensing Examination

ABSTRACT Phenomenon: There is growing concern over racial/ethnic bias in clinical care, yet how best to reduce bias remains challenging, in part because the sources of bias in medical education are poorly understood. One possible source is the routinized use of race/ethnicity in lectures, assessment, and preparatory materials, including question banks for licensing examinations. Because students worldwide use question banks to prepare for the United States Medical Licensing Examination, we examined how race/ethnicity was used in one of the most commonly recommended question banks. Approach: We analyzed the use of race/ethnicity in all 2,211 questions in a question bank for Step 1 of the United States Medical Licensing Examination for the following: the frequency of mentions of racial/ethnic groups, whether the use of race/ethnicity was merely descriptive or was central to any part of the question, and whether the question associated race/ethnicity with genetic difference. Findings. In sum, 455 of the 2,011 (20.6%) of the questions in the question bank referred to race/ethnicity in the question stem, answer, or educational objective. The frequency of mentions of racial/ethnicity was disproportionate to the U.S. population: 85.8% referred to White/Caucasians, 9.70% to Black/African Americans, 3.16% to Asian, 0.633% to Hispanics, and 0.633% to Native Americans. No cases referred to Native Hawaiians/Pacific Islanders. The proportion of mentions of race/ethnicity classified as either a routine descriptor or central to the case varied by racial/ethnic category. The association between genetics and disease in cases also varied by racial/ethnic category. Insights. The routinized use of race/ethnicity with no specific goal in preparation materials, such as question banks, risks contributing to racial bias. The implications of routinized use extend to assessment in medical education. Race/ethnicity should be used only when referring to social experiences of groups relevant to their health, not as a proxy for genetics, social class, or culture.