Reduced oxygen tension culturing conditionally alters toxicogenic response of differentiated H9c2 cardiomyoblasts to acrolein.

Acrolein is a reactive electrophilic aldehyde known to cause mitochondrial dysfunction, oxidative stress, and dysregulation of signaling transduction in vitro. Most in vitro systems employ standard cell culture maintenance conditions of 95% air/5% CO2, translating to a culture oxygen tension of approximately 20%, far above most physiological tissues. The purpose of this investigation was to examine whether low-serum, retinoic acid differentiated H9c2 cells were less sensitive to acrolein insult when cultured under reduced oxygen tension. H9c2 cells were maintained separately in 20% and 5% oxygen, differentiated for 5 d, and then exposed to acrolein for 30 min in media containing varying concentrations of tricarboxylic acid and glycolytic substrates, followed by fresh medium replacement. Cells were then assessed for MTT reduction at 2 h and 24 h after acrolein insult. We showed that pyruvate supplementation in combination with lowered oxygen culturing significantly attenuated acrolein-induced viability loss at 24 h. Poly(ADP-ribose) polymerase inhibition and EGTA preferentially provided partial rescue to low oxygen cultures, but not for standard cultures. Collectively, these results offer evidence supporting altered toxicogenic response of H9c2 during physiologically relevant oxygen tension culturing.

A novel method for deriving thresholds of toxicological concern for vaccine constituents.

Safety assessment evaluating the presence of impurities, residual materials, and contaminants in vaccines is a focus of current research. Thresholds of toxicological concern (TTCs) are mathematically modeled levels used for assessing the safety of many food and medication constituents. In this study, six algorithms are selected from the open-access ToxTree software program to derive a method for calculating TTCs for vaccine constituents: In Vivo Rodent Micronucleus assay/LD50, Benigni-Bossa/LD50, Cramer Extended/LD50, In Vivo Rodent Micronucleus assay/TDLo, Benigni-Bossa/TDLo, and the Cramer Extended/TDLo. Using an initial dataset (n = 197) taken from INCHEM, RepDose, RTECS, and TOXNET, the chemicals were divided into two families: "positive" - based on the presence of structures associated with adverse outcomes, or "negative" - no such structures or having structures that appear to be protective of health. The final validation indicated that the Benigni-Bossa/LD50 method is the most appropriate for calculating TTCs for vaccine constituents. Final TTCs were designated as 18.06 µg/person and 20.61 µg/person for the Benigni-Bossa/LD50 positive and negative structural families, respectively.

Occupational health surveillance: Pulmonary function testing in emergency responders.

Emergency responders may be exposed to a variety of fumes, gases, and particulates during the course of their job that can affect pulmonary function (PF) and require the use of respiratory protection. This investigation used occupational health monitoring examination data to characterize PF in a population currently employed as emergency responders. PF tests for workers who required health examinations to ensure fitness for continued respirator use were compared to the National Health and Nutrition Examination Survey (NHANES) III Raw Spirometry database to determine if decreased PF was associated with employment as an emergency responder. The results of this research indicated that the emergency responders experienced a modest, but statistically significant, increase in forced expiratory volume in 1 second (FEV1) and forced vital capacity (FVC) mean values over the NHANES III population in both total and stratified analyses, including stratification by age, gender, height, and smoking history. Results are likely due to a combination of effectively controlled exposures in the workplace, and the healthy worker effect among long-term workers. PF testing required by the Occupational and Safety Health Administration (OSHA) has substantial utility for conducting occupational surveillance at the population level. In this investigation, we were able to quickly evaluate if abnormal PF existed in an industrial sector known to have exposures that, when uncontrolled, can lead to PF impairment.

Hepatoprotective effects of select water-soluble PARP inhibitors in a carbon tetrachloride model.

BACKGROUND: Inhibitors of the nuclear enzyme poly (ADP-ribose) polymerase (PARP-1) have been demonstrated to attenuate pathophysiologic conditions associated with oxidative stress, specifically with carbon tetrachloride (CT)-induced hepatotoxicity. SETTINGS AND DESIGN: In this investigation, we evaluated 3 previously untested water-soluble PARP-1 inhibitors, namely, 3-aminobenzamide (ABA), 5-aminoisoquinolinone (AIQ), and N-(6-oxo-5,6-dihydro-phenanthridin-2-yl)-N,N-dimethylacetamide HCl (PJ-34) to determine their efficacy in blocking or attenuating CT-induced hepatotoxicity in male imprinting control region (ICR) mice. STATISTICAL ANALYSIS: Indicators of hepatotoxicity were compared with F-tests among groups to determine statistically significant effects. Pearson's correlation coefficients were used to evaluate the correlation between PARP inhibition and the attenuation of hepatotoxicity. RESULTS AND CONCLUSIONS: CT treatment resulted in hepatic cytotoxicity, increased serum transaminase (ALT), lipid peroxidation (MDA), intracellular glutathione (GSH) depletion, increased carbonyl content, and substantially increased PARP-1 activity. CT treatment also produced profound observable hemorrhagic necrosis in the hepatic centrilobular region of ICR mice. Pretreatment with PJ-34, ABA, and AIQ before CT treatment significantly decreased PARP-1 activity in hepatocytes after CT treatment by 3.4, 2.0, and 1.9 times, respectively. Corresponding to this reduction in PARP-1 activity, a significant reduction in the ALT levels and MDA and a reduction in the GSH depletion were observed. Also, there were no visible tissue defects in the liver samples from animals pretreated with individual PARP-1 inhibitors before CT administration. These results demonstrate the efficacy of the 3 previously untested water-soluble PARP-1 inhibitors in attenuating CT-induced hepatocellular toxicity and further characterize the role of PARP-1 activation and oxidative stress among the cascade of events in hepatocellular necrosis induced by CT treatment.

Assessment of community healthcare providers ability and willingness to respond to emergencies resulting from bioterrorist attacks.

INTRODUCTION: Previous findings have demonstrated that preparedness and planning within the public health system are inadequately developed to respond to an act of biological or chemical terrorism. MATERIALS AND METHODS: This investigation used Internet-based surveys to assess the level of preparedness (PL) and willingness to respond (WTR) to a bioterrorism attack, and identify factors that predict PL and WTR among Florida community healthcare providers. Invitations were sent to 22,800 healthcare providers in Florida, which resulted in 2,279 respondents. RESULTS: Respondents included physicians (n=604), nurses (n=1,152), and pharmacists (n=486). The results indicated that only 32% of Florida healthcare providers were competent and willing to respond to a bioterrorism attack, 82.7% of providers were willing to respond in their local community, and 53.6% within the State. Respondents were more competent in administrative skills than clinical knowledge (62.8% vs. 45%). Areas in which respondents had the highest competency were the initiation of treatment and recognition of their clinical and administrative roles. Areas in which respondents showed the lowest competency were the ability to identify cases and the ability to communicate risk to others. About 55% of the subjects had previous bioterrorism training and 31.5% had conducted emergency drills. Gender, race, previous training and drills, perceived threats of bioterrorism attack, perceived benefits of training and drills, and feeling prepared were all predictors of overall preparedness. CONCLUSIONS: The findings suggest that only one-third of Florida community healthcare providers were prepared for a bioterrorism attack, which is an insufficient response rate to effectively respond to a bioterrorism incident.

Characterization of cancer risk from airborne benzene exposure.

Airborne benzene is a ubiquitous environmental air pollutant. However, research regarding ambient environmental benzene exposures and leukemogenesis is lacking. Alternatively, occupational exposure to significantly elevated levels of benzene is associated with acute myeloid leukemia (AML). This investigation uses ambient air monitoring data from six counties in the state of Florida to characterize the extrapolated cancer risk from airborne benzene concentrations. The study uses both a regulatory and comparative risk analysis methodology to appropriately frame "risk" for the public. Between the years 2003 and 2006, 3794 air samples were collected from 23 monitoring stations distributed in Broward, Duval, Orange, Miami-Dade, Hillsborough, and Pinellas counties. The mean benzene concentrations by site ranged from 0.18 to 3.58ppb. Extrapolated cumulative lifetime exposures ranged from 0.036 to 0.702ppm-years. Regulatory risk analysis resulted in cancer risk estimates ranging from 4.37 x10(-6) to 8.56 x 10(-5), all of which exceed the Florida Department of Environmental Protection acceptable risk of 1x10(-6). Comparative analysis with the epidemiologic literature indicates the association between benzene exposure and AML is related to cumulative exposures far in excess of 1ppm-years, with the likely threshold for benzene-induced leukemogenesis of 50ppm-years cumulative exposure. Based upon the results of this investigation, it is unreasonable to anticipate AML cases in Florida residents as a result of ambient airborne benzene concentrations.

Dermal absorption of a dilute aqueous solution of malathion.

Malathion is an organophosphate pesticide commonly used on field crops, fruit trees, livestock, agriculture, and for mosquito and medfly control. Aerial applications can result in solubilized malathion in swimming pools and other recreational waters that may come into contact with human skin. To evaluate the human skin absorption of malathion for the assessment of risk associated with human exposures to aqueous solutions, human volunteers were selected and exposed to aqueous solutions of malathion. Participants submerged their arms and hands in twenty liters of dilute malathion solution in either a stagnant or stirred state. The "disappearance method" was applied by measuring malathion concentrations in the water before and after human exposure for various periods of time. No measurable skin absorption was detected in 42% of the participants; the remaining 58% of participants measured minimal absorbed doses of malathion. Analyzing these results through the Hazard Index model for recreational swimmer and bather exposure levels typically measured in contaminated swimming pools and surface waters after bait application indicated that these exposures are an order of magnitude less than a minimal dose known to result in a measurable change in acetylcholinesterase activity. It is concluded that exposure to aqueous malathion in recreational waters following aerial bait applications is not appreciably absorbed, does not result in an effective dose, and therefore is not a public health hazard.

The spectrum of building-related airway disorders: difficulty in retrospectively diagnosing building-related asthma.

INTRODUCTION: The specific causes and mechanism(s) for asthma occurring among occupants of non-residential buildings with poor indoor air quality are not known, but allergic and nonallergic processes are possible explanations METHODS: Repeated indoor air quality measurements were made while employees were working in a building where cigarette smoking was allowed. Seven of 19 employees who sought medical care from their private physicians because of respiratory complaints received a diagnosis of asthma. Subsequently, 19 symptomatic employees were examined at the University of South Florida (USF) 2 +/- 0.8 months (mean +/- SD) after removal from the building. RESULTS: The first floor of the building, where employee complaints were prevalent, was characterized by markedly reduced outdoor fresh air supply, diminished air circulation to the occupant spaces, and elevated airborne concentrations of formaldehyde. Nineteen workers examined at the USF 2 +/- 0.8 months after leaving the building reported ear, nose, and throat irritation and asthma-like symptoms while working in the building. There was resolution of symptoms in most of the seven employees (37%) with asthma previously diagnosed by their private physician. In fact, 16 of 19 subjects (84%) reported resolution or significant improvement of symptoms. Among 11 persons with symptoms suggesting asthma while working in the building, 4 persons (21%) showed a negative provocative concentration of methacholine producing a 20% fall in FEV1, including two subjects with doctor-diagnosed asthma. CONCLUSIONS: Confirmation of building-related asthma is influenced by time factors and the clinical criteria used for diagnosis. A nonallergic mechanism seems operative in our cases. While considered an example of occupational asthma, building-related asthma is a challenge for the practicing physician to confirm retrospectively.

Cockatiel-induced hypersensitivity pneumonitis.

Diagnosing an environmental or occupationally related pulmonary disorder often involves a process of elimination. Unlike commonly diagnosed conditions in other specialties, a cause-and-effect relationship may be implied, yet other factors such as temporality and biologic plausibility are lacking. Our patient was referred with a suspected work-related pulmonary disorder. For several years, she had suffered with dyspnea on exertion and repeated flulike illnesses. She worked at an automobile repair garage that performed a large number of emission tests, and there was concern that her workplace exposures were the cause of her symptoms. After a careful review of her history, physical examination, and laboratory testing, we came to the conclusion that she had hypersensitivity pneumonitis related to pet cockatiels in her home. Clinical points of emphasis include the importance of a complete environmental history and careful auscultation of the chest when performing the physical examination. In addition, we encountered an interesting physical diagnostic clue, a respiratory sound that assisted with the eventual diagnosis.