A targeted health risk assessment following the Deepwater Horizon oil spill: polycyclic aromatic hydrocarbon exposure in Vietnamese-American shrimp consumers.

BACKGROUND: The Deepwater Horizon oil spill of 2010 prompted concern about health risks among seafood consumers exposed to polycyclic aromatic hydrocarbons (PAHs) via consumption of contaminated seafood. OBJECTIVE: The objective of this study was to conduct population-specific probabilistic health risk assessments based on consumption of locally harvested white shrimp (Litopenaeus setiferus) among Vietnamese Americans in southeast Louisiana. METHODS: We conducted a survey of Vietnamese Americans in southeast Louisiana to evaluate shrimp consumption, preparation methods, and body weight among shrimp consumers in the disaster-impacted region. We also collected and chemically analyzed locally harvested white shrimp for 81 individual PAHs. We combined the PAH levels (with accepted reference doses) found in the shrimp with the survey data to conduct Monte Carlo simulations for probabilistic noncancer health risk assessments. We also conducted probabilistic cancer risk assessments using relative potency factors (RPFs) to estimate cancer risks from the intake of PAHs from white shrimp. RESULTS: Monte Carlo simulations were used to generate hazard quotient distributions for noncancer health risks, reported as mean ± SD, for naphthalene (1.8 × 10-4 ± 3.3 × 10-4), fluorene (2.4 × 10-5 ± 3.3 × 10-5), anthracene (3.9 × 10-6 ± 5.4 × 10-6), pyrene (3.2 × 10-5 ± 4.3 × 10-5), and fluoranthene (1.8 × 10-4 ± 3.3 × 10-4). A cancer risk distribution, based on RPF-adjusted PAH intake, was also generated (2.4 × 10-7 ± 3.9 × 10-7). CONCLUSIONS: The risk assessment results show no acute health risks or excess cancer risk associated with consumption of shrimp containing the levels of PAHs detected in our study, even among frequent shrimp consumers.

Quantitative sputum analysis: neuraminidase and tuberculosis.

OBJECTIVES: Clinically sensitive screening tests for pulmonary tuberculosis. METHODS: Quantitation of sputum lysosomal enzymes derived from mycobacterium-infected macrophage. Neuraminidase in culture-positive sputa exemplifies such systems. RESULTS: Correlation coefficient between sputum neuraminidase values (n=18), obtained by fixed-volume samplers and variable volume micropipets, was 0.995. Mean sputum neuraminidase values among tuberculous (137) and non-tuberculous (117) patients were 15.08 and 0.90 mU per mL. Medians were 8.45 and 0.20 mU per mL. Non-parametric analysis concludes a significant difference between the groups at P<0.001. Sputum neuraminidase levels above 1.0 mU per mL characterized 126 of 137 tuberculosis patients (92.0%). CONCLUSIONS: (1) Calibrated sputum fluid samplers facilitate quantitation of sputum enzymes. (2) Sputum neuraminidase levels over 1.0 mU per mL associate with Mycobacterium tuberculosis in 92% of cases. (3) Sputum neuraminidase measurements offer a screening procedure with which to identify samples for more specific, but less sensitive tests.

Stability of adenosine deaminase during transportation.

STUDY OBJECTIVE: Measurement of pleural fluid adenosine deaminase (ADA) levels is useful in the differential diagnosis of pleural effusions. However, at ambient temperatures, the levels of this enzyme decline with time. The purpose of the present study was to identify, test, and optimize additives that stabilize ADA, consequently eliminating the need for dry ice or other cold specimen transport media. DESIGN: A preliminary screen of historically proven stabilizing agents for specific proteins demonstrated effectiveness of glycerol for maintenance of pleural fluid ADA levels. Systematic studies for exploitation of the glycerol effect included the following: (1) supplements to the glycerol of promising alternate compounds, (2) long-term stability studies at ambient and elevated temperatures, (3) a field test of an effective mixture as a means for reduction of specimen transport costs, (4) thermal stability studies for optimization of the agents for use at otherwise denaturing temperatures, and (5) inclusion of pleural fluids from patients with a variety of etiologies, including tuberculous pleurisy, in order to gauge the effectiveness of the stabilizing agents on both the high and low molecular weight forms of ADA. RESULTS: A mixture of glycerol and ethylene glycol, each at 5% concentration, maintained pleural fluid ADA levels for at least 21 days at both room temperatures and 37 degrees C. A field test of 32 pleural fluids found that ADA levels in specimens containing this mixture, sent to the laboratory by surface mail at ambient temperatures, were nearly identical to those in aliquots of the same fluids shipped over dry ice. The bias in the measurement was 0.49 IU/L, with a precision of 2.49 IU/L. The correlation coefficient between the two measurements was 0.97. Thermal stability studies found that tuberculous pleural fluids containing 10% glycerol and 0.10 mol/L sodium sulfate maintained constant ADA levels for at least 10 days at 45 degrees C, an otherwise denaturing temperature for nonstabilized specimens. CONCLUSION: The addition of stabilizing agents to pleural fluid specimens allows the transport of those specimens to distant laboratories at ambient temperatures without a decline in the ADA levels. Employment of those agents will decrease the cost of the test and facilitate its use in second- and third-world countries.