A pilot project in molecular cancer epidemiology: determination of benzo[a]pyrene -- DNA adducts in animal and human tissues by immunoassays

A highly-sensitive immunoassay utilizing antiserum specificfor benzo[a]pyrene covalently bound to DNA has been employedto probe for adducts in the DNA of animal and human tissuesand peripheral blood mononuclear cells. By enzyme-linked immunosorbentassay (ELISA) a dose-related increase in levels of benzo[a]pyrene—DNAadducts was observed in DNA from lung tissue of mice and rabbitsinjected i.p. with benzo[a]pyrene. Quantitation with ELISA wasconfirmed by i.p. injection of [³H]benzo[a]pyrene and determinationof adduct levels in lung DNA by radioactivity. Thus, the ELISAassay was determined to be quantitative for benzo[a]pyrene—DNAadducts in vivo, and the lower limit of detectability establishedat 0.08–0.10 fmol/µg DNA. At this level of sensitivityno significant differences were observed between DNA from peripheralblood mononuclear cells of dogs on smoke inhalation machinesand controls. In an attempt to probe for benzo[a]pyrene—DNAadducts in human subjects resulting from chronic environmentalexposure, lung tissue, lung tumor and blood samples were obtainedfrom patients hospitalized for lung cancer and other diseases.A detailed history of exposure to environmental sources of benzo[a]pyreneand to factors known to influence polycyclic aromatic hydrocarbonmetabolism was attempted for 15 patients. DNA was extractedfrom the lung tissue of 27 patients and blood cells of severalindividuals and assayed by ELISA; 5 patients appeared to havelow but measurable levels of benzo[a]pyrene—DNA adductsas determined by ELISA. All of these patients were in the lungcancer group. However, the number of subjects was too smallto draw conclusions relating exposure history to the occurrenceof hydrocarbon—DNA adducts. These preliminary resultsshould encourage further studies on the utilization of immunoassaysfor carcinogen—DNA adducts as a potential tool in epidemiologicalstudies attempting to relate biologically-effective dose ofcarcinogen to human cancer risk.     

Methodologic and logistic issues in conducting longitudinal birth cohort studies: lessons learned from the Centers for Children's Environmental Health and Disease Prevention Research

In anticipation of the National Children's Study, lessons can be learned from the smaller birth cohort studies conducted by five Centers for Children's Environmental Health and Disease Prevention Research funded by the National Institute of Environmental Health Sciences and the U.S. Environmental Protection Agency. The populations studied are diverse in ethnicity and social class and reside in urban and rural environments. Although almost all of the centers chose to enroll participants through medical care facilities, they had to develop independent staffs and structures because of the overburdened medical care system. Some of the lessons learned by the centers include the importance of continuous funding, building community partnerships to conduct culturally appropriate research, hiring bilingual and bicultural staff from the community, prioritizing research goals, developing biorepositories to ensure future utility of samples, instituting quality control procedures for all aspects of specimen and data collection, maintaining frequent contact with study participants, ensuring ethical conduct of the research in a changing medical-legal climate, and communicating results in a timely and appropriate manner to participants and the wider community. All centers underestimated the necessary start-up time, staff, and costs in conducting these birth cohort studies. Despite the logistical complexity and added expenses, all centers emphasize the importance of studying the impact of environmental exposures on those children most at risk, those living in minority and low-income communities. These centers present barriers encountered, solutions found, and considerations for future research, with the hope that the lessons learned can help inform the planning and conduct of the National Children's Study.     

Analysis and enumeration of T cells, B cells and NK cells using the monoclonal antibody fluorescence capability of a routine haematology analyser (Cell-Dyn CD4000)

This communication details a method for the quantitative and qualitative analysis of blood T-, B- and NK-cell populations using the Abbott Cell-Dyn CD4000 haematology analyser. A series of 66 ethylenediaminetetraacetic acid (EDTA)-anticoagulated samples with lymphocyte counts between 0.2 and 33.3 x 10(9)/l were selected and analysed with CD3, CD19, Ia and CD56 monoclonal reagents. The flow cytometry reference method utilized a lymphocyte gate defined by optical scatter, with phenotypic analyses referencing to this gate and the absolute lymphocyte count. The CD4000 method analysed all leucocyte events, set primary gates for specific immunophenotypic fractions, and then determined population counts by reference to the white blood cell (WBC) count. Comparisons of CD3+ T-cell and CD19+ B-cell numbers showed high coefficients of correlation (R(2) > 0.95) and agreement (y = 1.01x) between the CD4000 and flow cytometry reference methods. Lower coefficients of correlation were obtained for CD3-CD56+ (R(2) = 0.52) and CD3+CD56+ (R(2) = 0.83) components. No major discrepancies were observed, and the CD4000 procedures additionally provided qualitative insights into the possibility of T-cell activation. The potential to undertake immediate analysis of EDTA-anticoagulated blood samples to determine the nature of abnormal lymphocyte morphology or numbers represents a considerable advance in the capability of haematology laboratories.     

46,XX sex reversal with partial duplication of chromosome arm 22q

We present a case of 46,XX sex reversal in the absence of SRY but with partial duplication of chromosome 22q. The subject had multiple congenital anomalies but nearly complete masculinization of the external genitalia. Our case along with a previous case supports the existence of a gene on chromosome 22q that can trigger testis determination in the absence of SRY. We proposed that overexpression of the SOX10 gene at 22q13 might be the cause of sex reversal. We investigated 13 additional subjects with SRY-negative 46,XX sex reversal for microduplication of chromosome arm 22q in the region of SOX10 gene, but could not find evidence for it.     

Unilateral multicystic dysplastic kidney and contralateral megacalycosis. An unusual association

Dilation of the genitourinary tract is not always synonymous with obstruction. It is well known that malformations with apparent hydronephrosis and normal urinary flow can exist. In addition, two or more distinct malformations of the genitourinary tract can coexist in the same patient. We present a case of coexistence of a unilateral multicystic dysplastic kidney and contralateral megacalycosis associated with ipsilateral distal segmental megaureter. This association is unusual in the literature. Glomerular renal function was normal, with only a slight defect of renal concentration capacity.