In an established rat model of smoke inhalation injury, we conducted a dose-response study to examine the protective effects of Xigris [drotrecogin alfa (activated) (DrotAA)], a recombinant form of human activated protein C (APC). DrotAA is a serine protease (approximately 55 kD molecular weight) with the same amino acid sequence and the glycosylation site as human plasma-derived APC. A total of 120 F344/NH rats (half each gender, approximately 175 g body weight) were randomly divided into five groups and exposed nose-only to air or diesel fuel smoke for 20 min. These rats were then i.v. administered with DrotAA in 0, 5, 10, and 20 mg/kg body weight, respectively, immediately following smoke exposure. Treatment with DrotAA significantly attenuated smoke inhalation injury in a dose-dependent manner at 2 hours after insult, as indicated by preserving microvascular permeability and proinflammatory cytokine IL-1beta (but not TNF-alpha and neuropeptide substance P) in bronchoalveolar lavage fluid (BALF). Moreover, the rats treated with 20 mg/ kg of DrotAA had an improvement of the expiration phase of pulmonary dynamic compliance. At all dosages, however, DrotAA also significantly increased all phases of pulmonary resistance compared with either the controls or to smoke inhalation alone. Generally, these data suggest that DrotAA may exert an anti-inflammatory effect by inhibiting cytokine-mediated inflammatory amplification. However, additional studies following a clinical course are needed to confirm the maximum efficiency and possible side effects of this recombined human activated protein C.

No abstract

The increased morbidity of childhood leukemia in Fallon, Nevada and Sierra Vista, Arizona has prompted great health concern. The main characteristic that these two towns share is the environmental pollution attributed to metal ore from abandoned mining operations. Consequently, we have investigated the transcriptome effects of metal ores from these endemic areas using a human T-cell acute lymphoblastic leukemia cell line (T-ALL). Metal ore from Fallon significantly increased cell growth after 24, 48 and 72 h of incubation at 1.5 microg/mL concentration, as measured by trypan-blue. Sierra Vista ore significantly increased cell growth with 0.15 and 1.5 microg/mL following 72 h of incubation. From human cDNA microarray, results indicate that in total, eight genes, mostly metallothionein (MT) genes, were up-regulated and 10 genes were down-regulated following treatment of the T-ALL cells with 0.15 and 1.5 microg/mL of metal ores at 72 h, in comparison with untreated cells. Twenty-eight metals of both ores were quantified and their presence may be associated with the cell growth rate and dose-dependent activation of transcriptomes in immature T-cells.

Background. Two concurrent, childhood leukemia clusters have been identified in the southwestern United States at Fallon, Nevada, and Sierra Vista, Arizona. Additionally, Fallon, Nevada has also experienced concurrent contamination by atmospheric tungsten particles. The etiology of leukemia is not known. Hypothesized risk factors for leukemia are environmental exposure, genetic predisposition, and viral infection. Additionally, strong evidence supports a prenatal origin. Our objective is to generate testable hypotheses towards elucidating the probable, multi-factorial etiology of leukemia by identifying the exposures unique to Fallon, Nevada, and held in common with Sierra Vista, Arizona, then exposing C57BL/6 mice, while in utero, to these chemicals to ascertain their leukemogenic potential. Utilizing advances in medical geology to analyze tree rings, surface dust, lichens and atmospheric particulate matter, we have identified tungsten and arsenic as potentially relevant to leukemogenesis. Methods. We utilized microarray (Affymetrix 430A 2.0 mouse) and real-time RT-PCR of Dmbt1 transcriptome-expression in spleen tissue collected from four-week-old C57BL/6 mouse pups (N = 6-8/group/gender) exposed, while in utero, to tungstate, arsenite, tungstate/arsenite and longitudinal controls at 20% of the normalized exposure a human mother would receive during gestation at mean environmental concentrations. Results. Prenatal exposure to tungstate is associated with a 37 + 1.2-fold (p = 0.012) decrease in DMBT1 transcriptome-expression in mice expressing DMBT1 at high levels. Additionally, prenatal exposure to tungstate/arsenite significantly altered a cytokine-cytokine receptor interaction pathway associated with lymphocyte activation and a network associated with hematological/immunological disease. Conclusion. Because DMBT1 protein products are known to aggregate viruses and possibly regulate immune response, additional research is warranted to determine the potential that prenatal exposure to tungstate or tungstate/ arsenite has to increase susceptibility to viruses and to induce leukemogenesis.

Significantly elevated concentrations of sodium tungstate have been demonstrated in the atmospheric particulate matter in multiple communities experiencing elevated rates of childhood leukemia, but not in their respective control communities. Prenatal exposure to sodium tungstate in C57BL/6 mice significantly decreased the transcriptome expression of Dmbt1, a protein which functions to aggregate bacteria and viruses in lung mucosa and saliva. Additionally, network analysis of gene microarray data produced a significant network associated with hematological/immunological disease focused on genes involved in viral defense. We hypothesize that exposure to sodium tungstate alters immunological and hematological response to viral infection as measured by qRT‐PCR of RSV genes F & G during the fastigium of the infection, CBC with a differential, and RT2‐PCR for genes associated with immunological function. C57BL/6 mice, exposed prenatally to sodium tungstate, demonstated a differential response to RSV viral infection. Additionally, tungsten exposure in male mice has a deleterious effect on testes function.Supported by EPA Grant EM‐96963201