Enhancement of benzo[a]pyrene-induced sister chromatid exchanges in lymphocytes from cigarette smokers occupationally exposed to asbestos

The frequencies of base-line and benzo[a]pyrene [(BP) CAS 50-38-8]-induced sister chromatid exchanges (SCE) were measured in peripheral blood lymphocytes from 22 male asbestos-exposed workers and 10 nonexposed workers of comparable age. A clear association between cigarette smoking and asbestos exposure in the sensitivity of lymphocytes to BP was observed. Among asbestos-exposed workers, lymphocytes from those who smoked cigarettes were significantly more susceptible to the induction of SCE by in vitro exposure to BP (P = .01) than were lymphocytes from nonsmokers. Active smoking elevated the base-line SCE frequency in both asbestos-exposed and nonexposed workers (P = .001), and an interaction between smoking and asbestos in the production of base-line SCE was suggested (P = .07). Asbestos exposure alone was not associated with an enhanced susceptibility to the induction of SCE by BP or with an elevation of base-line SCE. Increased age was associated with an increase in SCE inducibility by BP (P = .01), and a history of smoking was marginally associated with SCE inducibility by BP (P = .07). These findings support the hypothesis that an increased susceptibility of asbestos-exposed individuals to polyaromatic hydrocarbon-induced cancer results from an enhanced sensitivity to the induction of genetic damage rather than to an asbestos-induced differential cellular metabolic capacity.     

Infection of mesothelial cells with human herpes virus 8 in human immunodeficiency virus-infected patients with Kaposi's sarcoma, Castleman's disease, and recurrent pleural effusions.

Recurrent pleural effusions are common complications of hospitalized patients with human immunodeficiency virus (HIV) infection and may pose difficult diagnostic dilemmas. A common cause of recurrent pleural effusions in up to 30% of HIV-seropositive patients is pulmonary involvement by Kaposi's sarcoma, a human herpesvirus 8 (HHV 8)-related neoplasm. The pathogenesis of these effusions is unclear. These recurrent effusions, although benign, have shown significant mesothelial atypia/reactive changes of uncertain etiology. We attempted to evaluate these effusions morphologically and molecularly for the presence of HHV 8, with particular attention to mesothelial cells. All recurrent pleural effusions, as defined by any effusion tapped for cytological examination on more than two occasions, in HIV-positive patients at the National Institutes of Health were examined from 1998 to the present. Cases were stratified according to patients with and without histologically confirmed HHV 8 disease manifestations. Five patients with HHV 8 diseases (four with disseminated Kaposi's sarcoma and one with Castleman's disease) were identified. As a control group, five effusions from HIV-seropositive patients without known HHV 8-related diseases were identified. Cytological examination of effusions in patients with HHV 8-related diseases demonstrated atypical/markedly reactive mesothelial cells accompanied by a polymorphous background of lymphocytes. Molecular studies for B- and T-cell clonality in microdissected whole samples showed no definitive clones in these cases. Conversely, polymerase chain reaction (PCR) studies for the HHV 8 virus was positive in these samples. PCR studies on pure populations of microdissected mesothelial cells from the HHV 8-related effusions were positive for HHV 8 sequences, whereas those from HIV patients with non-HHV 8 related diseases were negative. Immunohistochemistry for HHV 8 (monoclonal antibody to latent nuclear antigen (LNA-1; ORF-73) on cellblock material demonstrated scattered positive mesothelial cells in three of the five cases of HHV 8-associated effusions. HHV 8 has been recently implicated in the pathogenesis of Kaposi's sarcoma and primary effusion lymphoma. Mesothelial cells in recurrent pleural effusions from patients with Kaposi's sarcoma and Castleman's disease appear to be infected with HHV 8. Additional studies need to be done to define the role of mesothelial cell infection in the pathogenesis of these HHV 8-associated effusions and define the prognostic significance.     

A patient with Werner's syndrome and osteosarcoma presenting as scleroderma.

Werner's syndrome (WS) is often mistaken for scleroderma. We describe a patient with WS who presented with an enlarging, painful mass of the right knee that proved to be a juxtaarticular osteosarcoma of the distal femur. Recognition of WS and prompt investigation of any painful, enlarging masses to exclude sarcomatous degeneration will benefit these patients.     

Seroprevalence and risk factors for hepatitis C virus antibody in pregnant women.

OBJECTIVE: To better understand hepatitis C viropathies and seroprevalence by performing an epidemiologic analysis of pregnant women seropositive for antibody against hepatitis C. METHODS: We studied 1013 consecutive obstetric patients at Parkland Memorial Hospital who gave informed consent for detailed interviews and serotesting. Sera were analyzed for antibody to the hepatitis C virus using both C100-3 and RIBA-4 assays. Neonatal assessment was carried out in the immediate postpartum period. RESULTS: Hepatitis C antibody was detected in 2.28% (N = 23) of the 1005 women in whom analysis was completed. Factors associated with seropositivity included intravenous (IV) drug use, sexually transmitted diseases, hepatitis B infection, maternal age greater than 22.5 years, increased parity (eg, greater than 2.1), history of transfusion, and three or more different lifetime sexual partners or a sexual partner who used IV drugs. Maternal and neonatal outcome was not different between hepatitis C antibody-positive and -negative groups. CONCLUSIONS: Epidemiologic data are consistent with sexual and parenteral modes of transmission. Women with hepatitis C antibody did not have excessive perinatal complications compared with antibody-negative women. A model protocol and cost analysis for screening pregnant women for hepatitis C infection are presented. However, routine screening for hepatitis C is not advocated.     

A high fidelity tissue-based cardiac surgical simulator.

OBJECTIVE: Issues concerning the training and certification of surgical specialists have taken on great significance in the last decade. A realistic computer-assisted, tissue-based simulator developed for use in the training of cardiac surgical residents in the conduct of a variety of cardiac surgical procedures in a low-volume cardiothoracic surgery unit of a typical developing country is described. The simulator can also be used to demonstrate the function of technology specific to cardiac surgical procedures in a way that previously has only been possible via the conduct of a procedure on a live animal or human being. METHODS: A porcine heart in a novel simulated operating theatre environment with real-time simulated haemodynamic monitoring and coronary blood flow, in arrested and beating-heart modes, is used as a training tool for surgical residents. RESULTS: Standard and beating-heart coronary arterial bypass, aortic valve replacement, aortic homograft replacement and pulmonary autograft procedures can be simulated with high degrees of realism and with the superimposition of adverse clinical scenarios requiring valid decision making and clinical judgments to be made by the trainees. CONCLUSIONS: The cardiac surgical simulation preparation described here would appear to be able to contribute positively to the training of residents in low-volume centres, as well as having the potential for application in other settings as a training tool or clinical skills assessment or accreditation device. Collaboration with larger centres is recommended in order to accurately assess the utility of this preparation as an adjunctive cardiothoracic surgical training aid.