Performance of BAC for DBPs precursors' removal for one year with micro-polluted lake water in East-China

Effectiveness of biological activated carbon (BAC) filter in removing disinfection byproducts (DBPs) precursors of micro-polluted lake water for one year was conducted. The formation potential (FP) of DBPs (trihalomethanes (THMs), haloacetic acids (HAAs) and Nitrosamines (NAs)), dissolved organic carbon (DOC), molecular weight (MW) distribution and excitation emission matrix fluorescence (EEM) of dissolved organic material (DOM) in the influent and effluent of BAC were determined. The results indicated that the removal efficiency (RE) of DOC ranged from 42.9-28.3%. Neither virgin GAC nor long-term operated BAC could efficiently dispose of THMs and HAAs precursors (RE from 35.2-18.8%, from 42 to 8.4%, respectively), however, BAC still showed good ability in removal of NAs precursors after a year operation, of which RE just dropped from 81.7-69.6%. There was strong correlation between RE of NAs precursors and DOC with small MW (<0.5 kDa). The removal of HAAs precursors showed relatively close relation to aromatic protein-like components and soluble microbial pollutants (SMPs). Weak direct relationship was found between the water quality parameters and THMs precursors.

Deposition of graphene nanomaterial aerosols in human upper airways

Graphene nanomaterials have attracted wide attention in recent years on their application to state-of-the-art technology due to their outstanding physical properties. On the other hand, the nanotoxicity of graphene materials also has rapidly become a serious concern especially in occupational health. Graphene naomaterials inevitably could become airborne in the workplace during manufacturing processes. The inhalation and subsequent deposition of graphene nanomaterial aerosols in the human respiratory tract could potentially result in adverse health effects to exposed workers. Therefore, investigating the deposition of graphene nanomaterial aerosols in the human airways is an indispensable component of an integral approach to graphene occupational health. For this reason, this study carried out a series of airway replica deposition experiments to obtain original experimental data for graphene aerosol airway deposition. In this study, graphene aerosols were generated, size classified, and delivered into human airway replicas (nasal and oral-to-lung airways). The deposition fraction and deposition efficiency of graphene aerosol in the airway replicas were obtained by a novel experimental approach. The experimental results acquired showed that the fractional deposition of graphene aerosols in airway sections studied were all less than 4%, and the deposition efficiency in each airway section was generally lower than 0.03. These results indicate that the majority of the graphene nanomaterial aerosols inhaled into the human respiratory tract could easily penetrate through the head airways as well as the upper part of the tracheobronchial airways and then transit down to the lower lung airways, where undesired biological responses might be induced.

Modal analysis and efficient coupling of TE₀₁ mode in small-core THz Bragg fibers

We report a design of low-loss THz Bragg fibers with a core size on the order of wavelength that operates near the cutoff frequency of its TE01 mode. We also propose a broadband Y-type mode converter based on branched rectangular metallic waveguides to facilitate coupling between the TE01 mode of the Bragg fiber and the TEM mode in free space with 60% efficiency. Our fiber holds strong promise to facilitate beam-wave interaction in gyrotron for high-efficiency THz generation.

Factors Affecting the Incidence of Angel Wing in White Roman Geese: Stocking Density and Genetic Selection

The present study investigated stocking density and genetic lines, factors that may alter the severity and incidence of angel wing (AW), in White Roman geese. Geese (n = 384) from two genetically selected lines (normal- winged line, NL, and angel-winged line, AL, respectively) and one commercial line (CL) were raised in four pens. Following common commercial practice, low-stocking-density (LD), medium-stocking-density, and high-stocking-density treatments were respectively administered to 24, 32, and 40 geese per pen at 0 to 3 weeks (1.92 m²/pen) and 4 to 6 weeks (13.2 m²/pen) of age and to 24, 30, and 36 geese at 7 to 14 weeks (20.0 m²/pen) of age. The results revealed that stocking density mainly affected body weight gain in geese younger than 4 weeks, and that geese subjected to LD had a high body weight at 2 weeks of age. However, the effect of stocking density on the severity score of AW (SSAW) and incidence of AW (IAW) did not differ significantly among the treatments. Differences were observed among the genetic stocks; that is, SSAW and IAW were significantly higher in AL than in NL and CL. Genetic selection generally aggravates AW, complicating its elimination. To effectively reduce IAW, stocking density, a suspected causal factor, should be lower than that presently applied commercially.

Selection for Duration of Fertility and Mule Duck White Plumage Colour in a Synthetic Strain of Ducks (Anas platyrhynchos)

A synthetic strain of ducks (Anas platyrhynchos) was developed by introducing genes for long duration of fertility to be used as mother of mule ducklings and a seven-generation selection experiment was conducted to increase the number of fertile eggs after a single artificial insemination (AI) with pooled Muscovy semen. Reciprocal crossbreeding between Brown Tsaiya LRI-2 (with long duration of fertility) and Pekin L-201 (with white plumage mule ducklings) ducks produced the G0. Then G1 were intercrossed to produce G2 and so on for the following generations. Each female duck was inseminated 3 times, at 26, 29, and 32 weeks of age. The eggs were collected for 14 days from day 2 after AI. Individual data regarding the number of incubated eggs (Ie), the number of fertile eggs at candling at day 7 of incubation (F), the total number of dead embryos (M), the maximum duration of fertility (Dm) and the number of hatched mule ducklings (H) with plumage colour were recorded. The selection criterion was the breeding values of the best linear unbiased prediction animal model for F. The results show high percentage of exhibited heterosis in G2 for traits to improve (19.1% for F and 12.9% for H); F with a value of 5.92 (vs 3.74 in the Pekin L-201) was improved in the G2. Heritabilities were found to be low for Ie (h (2) = 0.07±0.03) and M (h (2) = 0.07±0.01), moderately low for Dm (h (2) = 0.13±0.02), of medium values for H (h (2) = 0.20±0.03) and F (h (2) = 0.23±0.03). High and favourable genetic correlations existed between F and Dm (rg = 0.93), between F and H (rg = 0.97) and between Dm and H (rg = 0.90). The selection experiment showed a positive trend for phenotypic values of F (6.38 fertile eggs in G10 of synthetic strain vs 5.59 eggs in G4, and 3.74 eggs in Pekin L-201), with correlated response for increasing H (5.73 ducklings in G10 vs 4.86 in G4, and 3.09 ducklings in Pekin L-201) and maximum duration of the fertile period without increasing the embryo mortality rate. The average predicted genetic response for F was 40% of genetic standard deviation per generation of selection. The mule ducklings' feather colour also was improved. It was concluded that this study provided results for a better understanding of the genetics of the duration of fertility traits in the common female duck bred for mule and that the selection of a synthetic strain was effective method of improvement.

Carbon nanotubes size classification, characterization and nasal airway deposition

Workers and researchers in the carbon nanotubes (CNT)-related industries and laboratories might be exposed to CNT aerosols while generating and handling CNT materials. From the viewpoint of occupational health, it is essential to study the deposition of CNT aerosol in the human respiratory tract to investigate the potential adverse health effects. In this study, a human nasal airway replica and two types of CNT materials were employed to conduct CNT nasal airway deposition studies. The two CNT materials were aerosolized by a nebulizer-based wet generation method, with size classified by three designated classification diameters (51, 101 and 215 nm), and then characterized individually in terms of their morphology and aerodynamic diameter. The nasal deposition experiments were carried out by delivering the size classified CNTs into the nasal airway replica in three different inspiratory flow rates. From the characterization study, it showed that the morphology of the size classified CNTs could be in a variety of complex shapes with their physical dimension much larger than their classification diameter. In addition, it was found that the aerodynamic diameters of the classified CNTs were slightly smaller than their classification diameter. The nasal deposition data acquired in this study showed that the deposition efficiency of CNTs in the nasal airway were generally less than 0.1, which implies that the majority of the CNTs inhaled into the nose could easily penetrate through the entire nasal airway and transit further down to the lower airways, possibly causing adverse health effects.

Mechanisms of pharmaceutical aerosol deposition in the respiratory tract

Aerosol delivery is noninvasive and is effective in much lower doses than required for oral administration. Currently, there are several types of therapeutic aerosol delivery systems, including the pressurized metered-dose inhaler, the dry powder inhaler, the medical nebulizer, the solution mist inhaler, and the nasal sprays. Both oral and nasal inhalation routes are used for the delivery of therapeutic aerosols. Following inhalation therapy, only a fraction of the dose reaches the expected target area. Knowledge of the amount of drug actually deposited is essential in designing the delivery system or devices to optimize the delivery efficiency to the targeted region of the respiratory tract. Aerosol deposition mechanisms in the human respiratory tract have been well studied. Prediction of pharmaceutical aerosol deposition using established lung deposition models has limited success primarily because they underestimated oropharyngeal deposition. Recent studies of oropharyngeal deposition of several drug delivery systems identify other factors associated with the delivery system that dominates the transport and deposition of the oropharyngeal region. Computational fluid dynamic simulation of the aerosol transport and deposition in the respiratory tract has provided important insight into these processes. Investigation of nasal spray deposition mechanisms is also discussed.

Genomewide Study of Salivary MicroRNAs for Detection of Oral Cancer

MicroRNAs (miRNAs) in human saliva have recently demonstrated to be potential biomarkers for diagnosis purposes. However, lack of well-characterized/matched clinical groups and lack of suitable endogenous control (EC) for salivary extracellular miRNA detection and normalization are among the restrictions of applying salivary-based miRNA biomarker discovery. In the present study, we examined the differential expression pattern of miRNAs among 4 groups of subjects-including patients with oral squamous cell carcinoma (OSCC), patients with OSCC in remission (OSCC-R), patients with oral lichen planus, and healthy controls (HCs)-using a genomewide high-throughput miRNA microarray. First, we systematically screened 10 pooling samples and 34 individual samples of different groups to find a proper EC miRNA. We then investigated the genomewide expression patterns of differentially expressed miRNAs in saliva of different groups using NanoString nCounter miRNA expression assay and real-time quantitative polymerase chain reaction, followed by construction of receiver operating characteristic curves to determine the sensitivity and specificity of the assay. We identified miRNA-191 as a suitable EC miRNA with minimal intergroup and intragroup variability, and we used it for normalization. Of more than 700 miRNAs tested, 13 were identified as being significantly deregulated in saliva of OSCC patients compared to HCs: 11 miRNAs were underexpressed (miRNA-136, miRNA-147, miRNA-1250, miRNA-148a, miRNA-632, miRNA-646, miRNA668, miRNA-877, miRNA-503, miRNA-220a, miRNA-323-5p), and 2 miRNAs were overexpressed (miRNA-24, miRNA-27b). MiRNA-136 was underexpressed in both OSCC vs. HCs and OSCC vs. OSCC-R. MiRNA-27b levels were significantly higher in OSCC patients compared to those found in HCs, patients with OSCC-R, and patients with oral lichen planus and served as a characteristic biomarker of OSCC. Receiver operating characteristic curve analyses showed that miRNA-27b could be a valuable biomarker for distinguishing OSCC patients from the other groups. Our novel findings established a reliable EC miRNA for salivary-based diagnostic and indicate that the salivary miRNA profiles are discriminatory in OSCC patients.

Aerosolised 5-azacytidine suppresses tumour growth and reprogrammes the epigenome in an orthotopic lung cancer model

BACKGROUND

Epigenetic silencing by promoter methylation and chromatin remodelling affects hundreds of genes and is a causal event for lung cancer. Treatment of patients with low doses of the demethylating agent 5-azacytidine in combination with the histone deacetylase inhibitor entinostat has yielded clinical responses. The subcutaneous dosing route for consecutive days and reduced bioavailability of 5-azacytidine because of inactivation by cytidine deaminase may limit the expansion of epigenetic therapy into Phase III trials. To mitigate these barriers, an aerosol of 5-azacytidine was generated and characterised.

METHODS

The effect of aerosol vs systemic delivery of 5-azacytidine on tumour burden and molecular response of engrafted lung tumours in the nude rat was compared.

RESULTS

Pharmacokinetics revealed major improvement in the half-life of 5-azacytidine in lung tissue with aerosol delivery. Aerosolised 5-azacytidine significantly reduced lung tumour burden and induced global demethylation of the epigenome at one-third of the comparable effective systemic dose. High commonality for demethylation of genes was seen in tumours sampled throughout lung lobes and across treated animals receiving the aerosolised drug.

CONCLUSION

Collectively, these findings show that aerosolised 5-azacytidine targets the lung, effectively reprogrammes the epigenome of tumours, and is a promising approach to combine with other drugs for treating lung cancer.

Biodegradable rapamycin-eluting nano-fiber membrane-covered metal stent placement to reduce fibroblast proliferation in experimental stricture in a canine model

BACKGROUND AND STUDY AIMS

The aim of the current study was to assess whether placement of the biodegradable rapamycin-eluting nano-fiber membrane-covered metal stent is followed by less fibroblast proliferation and tissue hyperplasia compared with bare stents in experimental stricture in a dog model.

METHODS

A total of 80 dog models of stricture were randomly divided into a control group (n = 20, no stent insertion), a bare stent group (BSG, n = 20, 1-week retention), and two drug-eluting stent sub-groups (DESG-1w, n = 20, 1-week retention; DESG-4w, n = 20, 4-week retention). Lower esophageal sphincter (LES) pressure, 5-minute barium height (5-mBH), and cardia diameter were assessed before, immediately after the procedure, and regularly thereafter for 6 months. Five dogs in each group were euthanized for histological examination at each follow-up assessment.

RESULTS

Stent insertion was well tolerated, with similar migration rates (0 % in BSG vs. 7.5 % in DESGs; P = 0.5441). At 6 months, LES pressure and 5-mBH improved in DESG-1w (26.70 ± 5.02 mmHg and 6.50 ± 2.98 cm) and DESG-4w (20.16 ± 5.50 mmHg and 1.54 ± 0.98 cm) compared with BSG (39.94 ± 5.22 mmHg and 11.1 ± 5.46 cm) (P < 0.05), with DESG-4w being more stable than DESG-1w (P < 0.05). The cardia maintained greater patency in the DESGs (7.10 ± 3.09 mm in DESG-1w; 9.16 ± 3.77 mm in DESG-4w) than in the BSG (1.86 ± 2.45 mm; P < 0.05). Reduced peak inflammatory reactions and scarring occurred in DESGs compared with the BSG (P < 0.05), with a better outcome in DESG-4w than in DESG-1w (P < 0.05).

CONCLUSIONS

In this experimental stricture model, rapamycin-eluting stents were more effective than bare stents for the reduction of fibroblast proliferation and tissue hyperplasia after stent placement. Furthermore, 4-week retention of the drug-eluting stent led to a better outcome than 1-week retention.

Depressed calcium-handling proteins due to endoplasmic reticulum stress and apoptosis in the diabetic heart are attenuated by argirein

Diabetic cardiomyopathy (DC) is a unique disease frequently complicated to diabetes mellitus, manifesting endoplasmic reticulum (ER) stress and depressed calcium-handling proteins. We hypothesized that the abnormal FKBP12.6, SERCA2a, and CASQ2 are consequent to ER stress and apoptosis that are likely due to an entity of inflammation. These abnormalities may be attributed to reactive oxygen species genesis from activated NADPH oxidase which could respond to argirein (AR) through its anti-inflammatory activity. Sprague Dawley rats were randomly divided into six groups. Except the normal group, rats were injected with streptozotocin (STZ; 60 mg/kg, i.p.) once. During weeks 5 to 8 following STZ injection, rats were treated (in milligrams per kilogram per day, i.g.) with aminoguanidine (AMG, 100; an inducible nitric oxide synthase and AGEs inhibitor) or three doses of AR (50, 100, and 200). FKBP12.6, SERCA2a, and CASQ2 and ER stress chaperones Bip and PERK and apoptotic molecules were monitored in vivo and in vitro. Impaired cardiac performance and downregulated FKBP12.6, SERCA2a, and CASQ2 were significant in DC in vivo, and abnormal calcium-handling proteins were also found in high-glucose-incubated myocytes in vitro. ER stress manifested by upregulated Bip and PERK was predominant in association with DNA ladder and upregulated Bax and downregulated BCL-2 in vivo and in vitro. AR is effective to attenuate these abnormalities compared to AMG. Diabetic myocardium has inflammatory entity expressed as ER stress contributing to downregulated calcium-handling proteins. AR has potential in managing DC through attenuating depressed calcium-handling proteins, activated ER stress, and apoptosis in the myocardium.

Thoracic fraction of inhaled fiber aerosol

Size-selective sampling is a health-related method to collect airborne particles based on penetration of inhaled particles into different regions of the human respiratory tract; thus, it is the most relevant sampling method to correlate health risks with occupational exposure. The current practice of sampling asbestos and other fibers is not a size-selective method. The thoracic size fraction, defined as the portion of inhaled particles that can penetrate through the larynx, has been suggested as the most relevant size-selective sampling method for fiber aerosol. The thoracic fraction is based on 1-deposition of inhaled spherical particles in the human extrathoracic airways for mouth breathing and corrected for the particle inhalability. There is no comparable information for fiber aerosols; therefore, there is no technical basis to ascertain whether the current thoracic fraction definition is suitable for fiber aerosols. No human data are available from controlled experiments of inhaled fiber aerosols for the obvious reason that most fiber materials are potentially hazardous when inhaled. Our approach was to measure penetration of fiber aerosol in realistic human oropharyngeal airway replicas and to compare that with data from spherical particles. We showed that realistic human oral airway replicas (including the oral cavity, pharynx, and larynx regions) provided useful spherical and fiber particle deposition in the human head airway. These data could be used to test the thoracic fraction curves. The spherical penetration is in agreement with human in vivo data used to establish the thoracic fraction curve. Fiber penetrations through the larynx of two human oral airway replicas were higher than those for spherical particles for the same aerodynamic diameter using the same replicas. The thoracic curve as defined for spherical particles, therefore, may not include some fibers that could penetrate to the thoracic region.

Evaluation of physical sampling efficiency for cyclone-based personal bioaerosol samplers in moving air environments

The need to determine occupational exposure to bioaerosols has notably increased in the past decade, especially for microbiology-related workplaces and laboratories. Recently, two new cyclone-based personal bioaerosol samplers were developed by the National Institute for Occupational Safety and Health (NIOSH) in the USA and the Research Center for Toxicology and Hygienic Regulation of Biopreparations (RCT & HRB) in Russia to monitor bioaerosol exposure in the workplace. Here, a series of wind tunnel experiments were carried out to evaluate the physical sampling performance of these two samplers in moving air conditions, which could provide information for personal biological monitoring in a moving air environment. The experiments were conducted in a small wind tunnel facility using three wind speeds (0.5, 1.0 and 2.0 m s(-1)) and three sampling orientations (0°, 90°, and 180°) with respect to the wind direction. Monodispersed particles ranging from 0.5 to 10 μm were employed as the test aerosols. The evaluation of the physical sampling performance was focused on the aspiration efficiency and capture efficiency of the two samplers. The test results showed that the orientation-averaged aspiration efficiencies of the two samplers closely agreed with the American Conference of Governmental Industrial Hygienists (ACGIH) inhalable convention within the particle sizes used in the evaluation tests, and the effect of the wind speed on the aspiration efficiency was found negligible. The capture efficiencies of these two samplers ranged from 70% to 80%. These data offer important information on the insight into the physical sampling characteristics of the two test samplers.

A wind tunnel test of newly developed personal bioaerosol samplers

In this study the performance of two newly developed personal bioaerosol samplers was evaluated. The two test samplers are cyclone-based personal samplers that incorporate a recirculating liquid film. The performance evaluations focused on the physical efficiencies that a personal bioaerosol sampler could provide, including aspiration, collection, and capture efficiencies. The evaluation tests were carried out in a wind tunnel, and the test personal samplers were mounted on the chest of a full-size manikin placed in the test chamber of the wind tunnel. Monodisperse fluorescent aerosols ranging from 0.5 to 20 microm were used to challenge the samplers. Two wind speeds of 0.5 and 2.0 m/sec were employed as the test wind speeds in this study. The test results indicated that the aspiration efficiency of the two test samplers closely agreed with the ACGIH inhalable convention within the size range of the test aerosols. The aspiration efficiency was found to be independent of the sampling orientation. The collection efficiency acquired from these two samplers showed that the 50% cutoff diameters were both around 0.6 microm. However the wall loss of these two test samplers increased as the aerosol size increased, and the wall loss of PAS-4 was considerably higher than that of PAS-5, especially in the aerosol size larger than 5 microm, which resulted in PAS-4 having a relatively lower capture efficiency than PAS-5. Overall, the PAS-5 is considered a better personal bioaerosol sampler than the PAS-4.

Florida Red Tide Toxins (Brevetoxins) and Longitudinal Respiratory Effects in Asthmatics

Having demonstrated significant and persistent adverse changes in pulmonary function for asthmatics after 1 hour exposure to brevetoxins in Florida red tide (Karenia brevis bloom) aerosols, we assessed the possible longer term health effects in asthmatics from intermittent environmental exposure to brevetoxins over 7 years. 125 asthmatic subjects were assessed for their pulmonary function and reported symptoms before and after 1 hour of environmental exposure to Florida red tide aerosols for upto 11 studies over seven years. As a group, the asthmatics came to the studies with normal standardized percent predicted pulmonary function values. The 38 asthmatics who participated in only one exposure study were more reactive compared to the 36 asthmatics who participated in ≥4 exposure studies. The 36 asthmatics participating in ≥4 exposure studies demonstrated no significant change in their standardized percent predicted pre-exposure pulmonary function over the 7 years of the study. These results indicate that stable asthmatics living in areas with intermittent Florida red tides do not exhibit chronic respiratory effects from intermittent environmental exposure to aerosolized brevetoxins over a 7 year period.

Aerosolized Red Tide Toxins (Brevetoxins) and Asthma: Continued health effects after 1 hour beach exposure

Blooms of the toxic dinoflagellate, Karenia brevis, produce potent neurotoxins in marine aerosols. Recent studies have demonstrated acute changes in both symptoms and pulmonary function in asthmatics after only 1 hour of beach exposure to these aerosols. This study investigated if there were latent and/or sustained effects in asthmatics in the days following the initial beach exposure during periods with and without an active Florida red tide.Symptom data and spirometry data were collected before and after 1 hour of beach exposure. Subjects kept daily symptom diaries and measured their peak flow each morning for 5 days following beach exposure. During non-exposure periods, there were no significant changes in symptoms or pulmonary function either acutely or over 5 days of follow-up. After the beach exposure during an active Florida red tide, subjects had elevated mean symptoms which did not return to the pre-exposure baseline for at least 4 days. The peak flow measurements decreased after the initial beach exposure, decreased further within 24 hours, and continued to be suppressed even after 5 days. Asthmatics may continue to have increased symptoms and delayed respiratory function suppression for several days after 1 hour of exposure to the Florida red tide toxin aerosols.

Review of Florida Red Tide and Human Health Effects

This paper reviews the literature describing research performed over the past decade on the known and possible exposures and human health effects associated with Florida red tides. These harmful algal blooms are caused by the dinoflagellate, Karenia brevis, and similar organisms, all of which produce a suite of natural toxins known as brevetoxins. Florida red tide research has benefited from a consistently funded, long term research program, that has allowed an interdisciplinary team of researchers to focus their attention on this specific environmental issue-one that is critically important to Gulf of Mexico and other coastal communities. This long-term interdisciplinary approach has allowed the team to engage the local community, identify measures to protect public health, take emerging technologies into the field, forge advances in natural products chemistry, and develop a valuable pharmaceutical product. The Review includes a brief discussion of the Florida red tide organisms and their toxins, and then focuses on the effects of these toxins on animals and humans, including how these effects predict what we might expect to see in exposed people.

Personal exposure to aerosolized red tide toxins (brevetoxins)

Florida red tides occur annually in the Gulf of Mexico from blooms of the marine dinoflagellate, Karenia brevis, which produces highly potent natural polyether toxins, brevetoxins. Several epidemiologic studies have demonstrated that human exposure to red tide aerosol could result in increased respiratory symptoms. Environmental monitoring of aerosolized brevetoxins was performed using a high-volume sampler taken hourly at fixed locations on Siesta Beach, Florida. Personal exposure was monitored using personal air samplers and taking nasal swab samples from the subjects who were instructed to spend 1 hr on Sarasota Beach during two sampling periods of an active Florida red tide event in March 2005, and in May 2008 when there was no red tide. Results showed that the aerosolized brevetoxins from the personal sampler were in modest agreement with the environmental concentration taken from a high-volume sampler. Analysis of nasal swab samples for brevetoxins demonstrated 68% positive samples in the March 2005 sampling period when air concentrations of brevetoxins were between 50 to 120 ng/m(3) measured with the high-volume sampler. No swab samples showed detectable levels of brevetoxins in the May 2008 study, when all personal samples were below the limit of detection. However, there were no statistical correlations between the amounts of brevetoxins detected in the swab samples with either the environmental or personal concentration. Results showed that the personal sample might provide an estimate of individual exposure level. Nasal swab samples showed that brevetoxins indeed were inhaled and deposited in the nasal passage during the March 2005 red tide event.

Evaluation of MR spectroscopy and diffusion-weighted MRI in detecting bone marrow changes in postmenopausal women with osteoporosis

AIM

To prospectively investigate the role of MR spectroscopy (MRS) and diffusion-weighted magnetic resonance imaging (DWI) in assessing vertebral marrow changes in postmenopausal women with osteoporosis.

MATERIALS AND METHODS

Seventy-eight postmenopausal women (mean age 63.7+/-3.5 years; range 55-81 years), who underwent dual-energy x-ray absorptiometry of the spine, were divided into three bone density groups (24 with normal, 25 with osteopaenic, and 29 with osteoporotic) based on T score. Both MRS and DWI of the L3 vertebral body were performed to calculate the marrow fat content and apparent diffusion coefficient (ADC). The results were compared between three groups and correlated with BMD.

RESULTS

Vertebral marrow fat content was significantly increased in the osteoporotic group (59.97+/-5.78%), when compared with that of the osteopaenic group (53.04+/-7.66%, p=0.001) and the normal bone density group (48.79+/-7.1%, p<0.001). ADC values in the osteoporotic, osteopaenic, and normal bone density groups were 0.39+/-0.02x10(-3)mm(2)/s, 0.41+/-0.02x10(-3)mm(2)/s, and 0.47+/-0.03x10(-3)mm(2)/s, respectively, with statistically significant difference (P<0.001). A statistically significant positive correlation between T scores and ADC existed (r=0.835, p<0.001). The vertebral marrow fat content was negatively correlated to the bone density (r=-0.639, p<0.001) and to marrow ADC (r=-0.554, p<0.001).

CONCLUSION

The postmenopausal women with osteoporosis exhibited a corresponding increase in vertebral marrow fat content as the bone density decreased. Marrow fat content and ADC were related to the bone density. MRS and DWI are helpful in evaluating the bone marrow changes in postmenopausal women.

Upregulated NADPH oxidase contributes to diabetic testicular complication and is relieved by strontium fructose 1,6-diphosphate

Diabetes is frequently associated with declining sexual function resulting from oxidative damage. NADPH oxidase is a major resource of reactive oxygen species (ROS) in the testes and is likely related to an activated endothelin-1 (ET-1) system. An activation of NADPH oxidase-ET-1 pathway was hypothesized in diabetic testopathy. We verified the hypothesis and tested if strontium fructose 1,6-diphosphate (FDP-Sr) could relieve these changes in diabetic testis as compared to testosterone propionate (TP) and sildenafil. Diabetes was produced in male Sprague-Dawley rats 8 weeks after a single injection of streptozotocin (STZ), and interventions with testosterone propionate (TP), sildenafil and FDP-Sr were conducted in the last 4 weeks. Blood glucose, testosterone, follicle stimulating hormone (FSH) , luteinizing hormone (LH) and expressions of NADPH oxidase subunits and the ET system were measured. Decreased insulin, FSH, LH and testosterone in serum were found associating with testicular oxidative stress in STZ-injected rats. Additionally, over-expressions of NADPH oxidase p22, p47, p67 subunits and the ET pathway were significant in the diabetic testis relative to normal and were completely abolished by FDP-Sr. Both TP and sildenafil were not beneficial to diabetic testopathy except serum androgen raised by TP. Activated NADPH oxidase and ET system are significant contributing to testis injury and are responded to FDP-Sr only, against both TP and sildenafil, by restoring the testis function and the hypothalamus-pituitary-testis axis. It is due to its extra-energy supply and an antioxidant activity of FDP-Sr.

Development of a personal bioaerosol sampler based on a conical cyclone with recirculating liquid film

This article describes the development of a novel, high-performance personal aerosol sampler intended to monitor occupational air pollution, specifically, microbial constituents. This prototype sampler has a horizontally positioned conical cyclone with recirculating liquid film and an ejection supply of adsorptive liquid into the inlet nozzle. Airborne pollutants were collected in the adsorptive liquid, thus improving the survivability of microbiological aerosol samples. Experimental modules of different dimensions were first evaluated. Based on the test results, a prototype sampler was fabricated and tested. Evaluation of the collection efficiency of the prototype unit indicated a higher than 90% collection efficiency for particles > 1.0 microm. The 50% cutoff diameter was between 0.70-0.75 microm. For assessment of the sampling process effect on the collected microorganisms, Bacillus thuringiensis was tested at a concentration of about 1.0 x 10(6) cells per cm(3). The viability in the prototype sampler decreased to 78% after 60 min of operation.

Inland Transport of Aerosolized Florida Red Tide Toxins

Florida red tides, an annual event off the west coast of Florida, are caused by the toxic dinoflagellate, Karenia brevis. K. brevis produces a suite of potent neurotoxins, brevetoxins, which kill fish, sea birds, and marine mammals, as well as sickening humans who consume contaminated shellfish. These toxins become part of the marine aerosol, and can also be inhaled by humans and other animals. Recent studies have demonstrated a significant increase in symptoms and decrease lung function in asthmatics after only one hour of beach exposure during an onshore Florida red tide bloom.This study constructed a transect line placing high volume air samplers to measure brevetoxins at sites beginning at the beach, moving approximately 6.4 km inland. One non-exposure and 2 exposure studies, each of 5 days duration, were conducted. No toxins were measured in the air during the non-exposure period. During the 2 exposure periods, the amount of brevetoxins varied considerably by site and by date. Nevertheless, brevetoxins were measured at least 4.2 kilometers from the beach and/or 1.6 km from the coastal shoreline. Therefore, populations sensitive to brevetoxins (such as asthmatics) need to know that leaving the beach may not discontinue their environmental exposure to brevetoxin aerosols.

Neonatal lipopolysaccharide exposure delays puberty and alters hypothalamic Kiss1 and Kiss1r mRNA expression in the female rat

Immunological challenge experienced in early life can have long-term programming effects on the hypothalamic-pituitary-adrenal axis that permanently influence the stress response. Similarly, neonatal exposure to immunological stress enhances stress-induced suppression of the hypothalamic-pituitary gonadal (HPG) axis in adulthood, but may also affect earlier development, including the timing of puberty. To investigate the timing of the critical window for this programming of the HPG axis, neonatal female rats were injected with lipopolysaccharide (LPS; 50 microg/kg i.p.) or saline on postnatal days 3 + 5, 7 + 9, or 14 + 16 and monitored for vaginal opening and first vaginal oestrus as markers of puberty. We also investigated the effects of neonatal programming on the development of the expression patterns of kisspeptin (Kiss1) and its receptor (Kiss1r) in hypothalamic sites known to contain kisspeptin-expressing neuronal populations critical to reproductive function: the medial preoptic area (mPOA) and the arcuate nucleus in neonatally-stressed animals. We determined that the critical period for a significant delay in puberty as a result of neonatal LPS exposure is before 7 days of age in the female rat, and demonstrated that Kiss1, but not Kiss1r mRNA, expression in the mPOA is down-regulated in pre-pubertal females. These data suggest that the mPOA population of kisspeptin neurones play a pivotal role in controlling the onset of puberty, and that their function can be affected by neonatal stress.

Exposure and effect assessment of aerosolized red tide toxins (brevetoxins) and asthma

BACKGROUND

In previous studies we demonstrated statistically significant changes in reported symptoms for lifeguards, general beach goers, and persons with asthma, as well as statistically significant changes in pulmonary function tests (PFTs) in asthmatics, after exposure to brevetoxins in Florida red tide (Karenia brevis bloom) aerosols.

OBJECTIVES

In this study we explored the use of different methods of intensive ambient and personal air monitoring to characterize these exposures to predict self-reported health effects in our asthmatic study population.

METHODS

We evaluated health effects in 87 subjects with asthma before and after 1 hr of exposure to Florida red tide aerosols and assessed for aerosolized brevetoxin exposure using personal and ambient samplers.

RESULTS

After only 1 hr of exposure to Florida red tide aerosols containing brevetoxin concentrations > 57 ng/m(3), asthmatics had statistically significant increases in self-reported respiratory symptoms and total symptom scores. However, we did not see the expected corresponding changes in PFT results. Significant increases in self-reported symptoms were also observed for those not using asthma medication and those living >/= 1 mile from the coast.

CONCLUSIONS

These results provide additional evidence of health effects in asthmatics from ambient exposure to aerosols containing very low concentrations of brevetoxins, possibly at the lower threshold for inducing a biologic response (i.e., toxicity). Consistent with the literature describing self-reported symptoms as an accurate measure of asthmatic distress, our results suggest that self-reported symptoms are a valuable measure of the extent of health effects from exposure to aerosolized brevetoxins in asthmatic populations.

Aerosol sampling system for collection of Capstone depleted uranium particles in a high-energy environment

The Capstone Depleted Uranium (DU) Aerosol Study was undertaken to obtain aerosol samples resulting from a large-caliber DU penetrator striking an Abrams or Bradley test vehicle. The sampling strategy was designed to (1) optimize the performance of the samplers and maintain their integrity in the extreme environment created during perforation of an armored vehicle by a DU penetrator, (2) collect aerosols as a function of time post perforation, and (3) obtain size-classified samples for analysis of chemical composition, particle morphology, and solubility in lung fluid. This paper describes the experimental setup and sampling methodologies used to achieve these objectives. Custom-designed arrays of sampling heads were secured to the inside of the target in locations approximating the breathing zones of the crew locations in the test vehicles. Each array was designed to support nine filter cassettes and nine cascade impactors mounted with quick-disconnect fittings. Shielding and sampler placement strategies were used to minimize sampler loss caused by the penetrator impact and the resulting fragments of eroded penetrator and perforated armor. A cyclone train was used to collect larger quantities of DU aerosol for measurement of chemical composition and solubility. A moving filter sample was used to obtain semicontinuous samples for DU concentration determination. Control for the air samplers was provided by five remotely located valve control and pressure monitoring units located inside and around the test vehicle. These units were connected to a computer interface chassis and controlled using a customized LabVIEW engineering computer control program. The aerosol sampling arrays and control systems for the Capstone study provided the needed aerosol samples for physicochemical analysis, and the resultant data were used for risk assessment of exposure to DU aerosol.

Physicochemical characterization of Capstone depleted uranium aerosols II: particle size distributions as a function of time

The Capstone Depleted Uranium (DU) Aerosol Study, which generated and characterized aerosols containing DU from perforation of armored vehicles with large-caliber DU penetrators, incorporated a sampling protocol to evaluate particle size distributions. Aerosol particle size distribution is an important parameter that influences aerosol transport and deposition processes as well as the dosimetry of the inhaled particles. These aerosols were collected on cascade impactor substrates using a pre-established time sequence following the firing event to analyze the uranium concentration and particle size of the aerosols as a function of time. The impactor substrates were analyzed using proportional counting, and the derived uranium content of each served as input to the evaluation of particle size distributions. Activity median aerodynamic diameters (AMADs) of the particle size distributions were evaluated using unimodal and bimodal models. The particle size data from the impactor measurements were quite variable. Most size distributions measured in the test based on activity had bimodal size distributions with a small particle size mode in the range of between 0.2 and 1.2 microm and a large size mode between 2 and 15 microm. In general, the evolution of particle size over time showed an overall decrease of average particle size from AMADs of 5 to 10 microm shortly after perforation to around 1 microm at the end of the 2-h sampling period. The AMADs generally decreased over time because of settling. Additionally, the median diameter of the larger size mode decreased with time. These results were used to estimate the dosimetry of inhaled DU particles.

Physicochemical characterization of Capstone depleted uranium aerosols IV: in vitro solubility analysis

As part of the Capstone Depleted Uranium (DU) Aerosol Study, the solubility of selected aerosol samples was measured using an accepted in vitro dissolution test system. This static system was employed along with a SUF (synthetic ultrafiltrate) solvent, which is designed to mimic the physiological chemistry of extracellular fluid. Using sequentially obtained solvent samples, the dissolution behavior over a 46-d test period was evaluated by fitting the measurement data to two- or three-component negative exponential functions. These functions were then compared with Type M and S absorption taken from the International Commission on Radiological Protection Publication 66 Human Respiratory Tract Model. The results indicated that there was a substantial variability in solubility of the aerosols, which in part depended on the type of armor being impacted by the DU penetrator and the particle size fraction being tested. Although some trends were suggested, the variability noted leads to uncertainties in predicting the solubility of other DU-based aerosols. Nevertheless, these data provide a useful experimental basis for modeling the intake-dose relationships for inhaled DU aerosols arising from penetrator impact on armored vehicles.

Methods used to calculate doses resulting from inhalation of Capstone depleted uranium aerosols

The methods used to calculate radiological and toxicological doses to hypothetical persons inside either a U.S. Army Abrams tank or Bradley Fighting Vehicle that has been perforated by depleted uranium munitions are described. Data from time- and particle-size-resolved measurements of depleted uranium aerosol as well as particle-size-resolved measurements of aerosol solubility in lung fluids for aerosol produced in the breathing zones of the hypothetical occupants were used. The aerosol was approximated as a mixture of nine monodisperse (single particle size) components corresponding to particle size increments measured by the eight stages plus the backup filter of the cascade impactors used. A Markov Chain Monte Carlo Bayesian analysis technique was employed, which straightforwardly calculates the uncertainties in doses. Extensive quality control checking of the various computer codes used is described.

Physicochemical characterization of Capstone depleted uranium aerosols I: uranium concentration in aerosols as a function of time and particle size

During the Capstone Depleted Uranium (DU) Aerosol Study, aerosols containing DU were produced inside unventilated armored vehicles (i.e., Abrams tanks and Bradley Fighting Vehicles) by perforation with large-caliber DU penetrators. These aerosols were collected and characterized, and the data were subsequently used to assess human health risks to personnel exposed to DU aerosols. The DU content of each aerosol sample was first quantified by radioanalytical methods, and selected samples, primarily those from the cyclone separator grit chambers, were analyzed radiochemically. Deposition occurred inside the vehicles as particles settled on interior surfaces. Settling rates of uranium from the aerosols were evaluated using filter cassette samples that collected aerosol as total mass over eight sequential time intervals. A moving filter was used to collect aerosol samples over time, particularly within the first minute after a shot. The results demonstrate that the peak uranium concentration in the aerosol occurred in the first 10 s after perforation, and the concentration decreased in the Abrams tank shots to about 50% within 1 min and to less than 2% after 30 min. The initial and maximum uranium concentrations were lower in the Bradley vehicle than those observed in the Abrams tank, and the concentration levels decreased more slowly. Uranium mass concentrations in the aerosols as a function of particle size were evaluated using samples collected in a cyclone sampler, which collected aerosol continuously for 2 h after perforation. The percentages of uranium mass in the cyclone separator stages ranged from 38 to 72% for the Abrams tank with conventional armor. In most cases, it varied with particle size, typically with less uranium associated with the smaller particle sizes. Neither the Abrams tank with DU armor nor the Bradley vehicle results were specifically correlated with particle size and can best be represented by their average uranium mass concentrations of 65 and 24%, respectively.

Balloon-Based In Vitro MDI Aerosol Deposition Experiments on the Effects of Mouthpiece Diameter

For this article, we studied the effects of mouthpiece diameter and flow rate on aerosol penetration efficiency for metered-dose inhaler (MDI) applications. Measurements show that increasing the mouthpiece diameter has a moderate and positive influence on the particle penetration efficiency of the MDI. The particle penetration efficiency increases monotonically with the increase of the mouthpiece diameter from 16 mm to 20 mm. Second, the experiments show that airflow rate has an apparent and significant effect on particles deposition in the oral airway. The reduction of the airflow rate from 90 L/min to 30 L/min tripled the penetration efficiency of the MDI. A new experimental system has been employed to measure the particles deposition in the human airways. Expansion balloons were used to induce airflow as well as to collect the penetrated particles through an airway cast. The potential advantages of the balloon-based experimental system are simplicity, accuracy, and cost-effectiveness.

Fiber Deposition Pattern in Two Human Respiratory Tract Replicas

This study consisted of a series of experiments to investigate the factors that might affect the fiber deposition pattern in the human respiratory tract. Carbon fibers with uniform diameter and polydispersed length were chosen as the test material. Two geometry-defined human respiratory tract replicas encompassing the oral cavity, oropharynx, larynx, trachea, and first few bifurcations of the tracheobronchial airways were used in this research. Deposition studies were conducted by delivering aerosolized carbon fibers into the replicas at constant inspiratory flow rates of 15, 43.5, and 60 L/min. The results showed that impaction is the dominant deposition mechanism for both replicas. Most of the fibers with high momentum deposited in the oral airway (oral cavity to larynx), and fibers with low momentum were found to pass through the entire replica easily. When comparing the results between the two replicas, fiber length, inspiratory flow rate, and the geometry of the oral airway were found to be factors that might affect the fiber deposition pattern in the human respiratory tract.

Aerosolized red-tide toxins (brevetoxins) and asthma

BACKGROUND

With the increasing incidence of asthma, there is increasing concern over environmental exposures that may trigger asthma exacerbations. Blooms of the marine microalgae, Karenia brevis, cause red tides (or harmful algal blooms) annually throughout the Gulf of Mexico. K brevis produces highly potent natural polyether toxins, called brevetoxins, which are sodium channel blockers, and possibly histamine activators. In experimental animals, brevetoxins cause significant bronchoconstriction. In humans, a significant increase in self-reported respiratory symptoms has been described after recreational and occupational exposures to Florida red-tide aerosols, particularly among individuals with asthma.

METHODS

Before and after 1 h spent on beaches with and without an active K brevis red-tide exposure, 97 persons >or= 12 years of age with physician-diagnosed asthma were evaluated by questionnaire and spirometry. Concomitant environmental monitoring, water and air sampling, and personal monitoring for brevetoxins were performed.

RESULTS

Participants were significantly more likely to report respiratory symptoms after K brevis red-tide aerosol exposure than before exposure. Participants demonstrated small, but statistically significant, decreases in FEV(1), midexpiratory phase of forced expiratory flow, and peak expiratory flow after exposure, particularly among those participants regularly using asthma medications. No significant differences were detected when there was no Florida red tide (ie, during nonexposure periods).

CONCLUSIONS

This study demonstrated objectively measurable adverse changes in lung function from exposure to aerosolized Florida red-tide toxins in asthmatic subjects, particularly among those requiring regular therapy with asthma medications. Future studies will assess these susceptible subpopulations in more depth, as well as the possible long-term effects of these toxins.

A quantitative analysis of aerosols inside an armored vehicle perforated by a kinetic energy penetrator containing tungsten, nickel, and cobalt

These tests were conducted to develop a database that could be used to assess risks to soldiers from exposure to aerosolized metallic particulates when the crew compartment of an Abrams tank is perforated by a kinetic energy penetrator. Quantitative data are reported for aerosols produced by kinetic energy penetrators containing tungsten, nickel, and cobalt. The following are addressed: (1) concentrations and rates of particle settling inside the vehicle, (2) particle size distribution, (3) inhalable and respirable particulates, (4) distribution of aerosol particles by mass, and (5) particle shapes. The scenario described in this report simulates a rare occurrence. The lessons learned, however, highlight a requirement for developing protocols for analyses of metals in body fluids and urine as soon as practical, and also for implementing targeted postdeployment medical surveillance programs that monitor both body burden for respired metals and pulmonary function.

Selection responses in duration of fertility and its consequences on hatchability in the intergeneric crossbreeding of ducks

1. From 1992 to 2003, selected (S) and control lines (C) of the laying Brown Tsaiya duck (Anas platyrhynchos) were simultaneously maintained under the same standardised conditions of feeding and management. 2. The selection objective was to increase the number of fertile eggs after a single artificial insemination (AI) with pooled Muscovy semen. From generations G1 to G11, 2452 and 2022 female ducks, in S and C lines, respectively, were measured and recorded. In the S line, the percentage selected varied between 20.2 and 34.3% in females and between 7.2 and 20.8% in males. 3. Selection for number of fertile eggs had a correlated effect of increasing the parameter tau of the logistic curves which fitted the daily variations (d 2 to 15) in fertility or hatchability on the basis of eggs set. The differences S-C for the estimates of the times of half maximal fertility and hatchability increased by 0.41 and 0.37 d per generation between G1 and G11, respectively. 4. The highest increases of fertility per day rates after a single AI were observed between d 5 and 11. Moreover, in the selected line, fertility rate was higher than, or equal to, 90% in d 2 from G8. The same tendencies were observed for the changes in the evolution of hatchability on the basis of eggs set. 5. Selection increased fertility and hatchability according to the egg set rates, especially for d 2 to 8 after AI. Hatchability of fertile eggs was not impaired, confirming that selection for one AI per week was possible in this strain of laying ducks.

Evaluation of Nebulizer Performance under Various Humidity Conditions

Jet nebulizers are a drug delivery tool commonly used for treating respiratory diseases. When a nebulizer generates aerosols, the rate at which droplets evaporate depends on humidity conditions around the nebulizer outlet. Because the relative humidity (RH) of the air affects the evaporation rate, the aerosol distribution and drug delivery dose is also affected by RH. Four nebulizers were chosen for comparison in this study: PARI LC Plus (PARI Respiratory Equipment, Inc., Midlothian, VA), SideStream (Medic-Aid Ltd., UK), VixOne (Westmed, Inc., Tucson, AZ), and Micromist (Hudson Respiratory Care Inc., Temecula, CA). Two different formulations were used: albuterol (liquid solution) and budesonide (suspension). Particle distribution (mass median aerodynamic diameter [MMAD] and geometric standard deviation [GSD]), nebulizer efficiency (total efficiency and respirable fraction [RF] efficiency for particles less than 4.7 microm), and dead volume (the amount of solution remaining after nebulization) were compared at the RH of 5%, 50%, and 80%. Our results showed that the MMAD increased (p value varied from <0.001 to 0.016) with the increase in RH, except for with the VixOne unit with albuterol (p = 0.24). The MMAD from the budesonide always appeared higher than from the albuterol. The RF (and thus, the inhalation dose) was lower with a higher RH. Except for the PARI LC Plus with budesonide, the RF decreased approximately 15-27% when the RH rose from 5% to 50%. For the PARI LC Plus nebulizer, the lower dead volume (0.22 mL) with higher residual drugs (62.3% of total drug) was obtained at an RH of 5% comparing the RH of 50% and 80% because of the unit's unique design.

Concentration and particle size of airborne toxic algae (brevetoxin) derived from ocean red tide events

Red tides in the Gulf of Mexico are formed by blooms of the dinoflagellate Karenia brevis, which produces brevetoxins (PbTx). Brevetoxins can be transferred from water to air in the wind-powered whitecapped waves during red tide episodes. Inhalation exposure to marine aerosol containing PbTx causes respiratory problems. A liquid chromatograph/ tandem mass spectrometric method was developed for the detection and quantitation of several PbTxs in ambient samples collected during red tide events. This method was complemented by a previously developed antibody assay that analyzes the entire class of PbTx compounds. The method showed good linearity, accuracy, and reproducibility, allowing quantitation of PbTx compounds in the 10 pg/m3 range. Air concentrations of PbTxs and brevenal for individual samples ranged from 0.01 to 80 ng/m3. The particle size showed a single mode with a mass median diameter between 6 and 10 microm, which was consistent for all of the PbTx species that were measured. Our results imply that individual PbTxs were from the same marine aerosol or from marine aerosol that was produced from the same process. The particle size indicated the likelihood of high deposition efficiency in the respiratory tract with the majority of aerosol deposited in the upper airways and small but not insignificant deposition in the lower airways.

Characterization of marine aerosol for assessment of human exposure to brevetoxins

Red tides in the Gulf of Mexico are commonly formed by the fish-killing dinoflagellate Karenia brevis, which produces nine potent polyether brevetoxins (PbTxs). Brevetoxins can be transferred from water to air in wind-powered white-capped waves. Inhalation exposure to marine aerosol containing brevetoxins causes respiratory symptoms. We describe detailed characterization of aerosols during an epidemiologic study of occupational exposure to Florida red tide aerosol in terms of its concentration, toxin profile, and particle size distribution. This information is essential in understanding its source, assessing exposure to people, and estimating dose of inhaled aerosols. Environmental sampling confirmed the presence of brevetoxins in water and air during a red tide exposure period (September 2001) and lack of significant toxin levels in the water and air during an unexposed period (May 2002). Water samples collected during a red tide bloom in 2001 showed moderate-to-high concentrations of K. brevis cells and PbTxs. The daily mean PbTx concentration in water samples ranged from 8 to 28 microg/L from 7 to 11 September 2001; the daily mean PbTx concentration in air samples ranged from 1.3 to 27 ng/m(3). The daily aerosol concentration on the beach can be related to PbTx concentration in water, wind speed, and wind direction. Personal samples confirmed human exposure to red tide aerosols. The particle size distribution showed a mean aerodynamic diameter in the size range of 6-12 microm, with deposits mainly in the upper airways. The deposition pattern correlated with the observed increase of upper airway symptoms in healthy lifeguards during the exposure periods.

Occupational exposure to aerosolized brevetoxins during Florida red tide events: effects on a healthy worker population

Karenia brevis (formerly Gymnodinium breve) is a marine dinoflagellate responsible for red tides that form in the Gulf of Mexico. K. brevis produces brevetoxins, the potent toxins that cause neurotoxic shellfish poisoning. There is also limited information describing human health effects from environmental exposures to brevetoxins. Our objective was to examine the impact of inhaling aerosolized brevetoxins during red tide events on self-reported symptoms and pulmonary function. We recruited a group of 28 healthy lifeguards who are occupationally exposed to red tide toxins during their daily work-related activities. They performed spirometry tests and reported symptoms before and after their 8-hr shifts during a time when there was no red tide (unexposed period) and again when there was a red tide (exposed period). We also examined how mild exercise affected the reported symptoms and spirometry tests during unexposed and exposed periods with a subgroup of the same lifeguards. Environmental sampling (K. brevis cell concentrations in seawater and brevetoxin concentrations in seawater and air) was used to confirm unexposed/exposed status. Compared with unexposed periods, the group of lifeguards reported more upper respiratory symptoms during the exposed periods. We did not observe any impact of exposure to aerosolized brevetoxins, with or without mild exercise, on pulmonary function.

Initial evaluation of the effects of aerosolized Florida red tide toxins (brevetoxins) in persons with asthma

Florida red tides annually occur in the Gulf of Mexico, resulting from blooms of the marine dinoflagellate Karenia brevis. K. brevis produces highly potent natural polyether toxins, known as brevetoxins, that activate voltage-sensitive sodium channels. In experimental animals, brevetoxins cause significant bronchoconstriction. A study of persons who visited the beach recreationally found a significant increase in self-reported respiratory symptoms after exposure to aerosolized Florida red tides. Anecdotal reports indicate that persons with underlying respiratory diseases may be particularly susceptible to adverse health effects from these aerosolized toxins. Fifty-nine persons with physician-diagnosed asthma were evaluated for 1 hr before and after going to the beach on days with and without Florida red tide. Study participants were evaluated with a brief symptom questionnaire, nose and throat swabs, and spirometry approved by the National Institute for Occupational Safety and Health. Environmental monitoring, water and air sampling (i.e., K. brevis, brevetoxins, and particulate size distribution), and personal monitoring (for toxins) were performed. Brevetoxin concentrations were measured by liquid chromatography mass spectrometry, high-performance liquid chromatography, and a newly developed brevetoxin enzyme-linked immunosorbent assay. Participants were significantly more likely to report respiratory symptoms after Florida red tide exposure. Participants demonstrated small but statistically significant decreases in forced expiratory volume in 1 sec, forced expiratory flow between 25 and 75%, and peak expiratory flow after exposure, particularly those regularly using asthma medications. Similar evaluation during nonexposure periods did not significantly differ. This is the first study to show objectively measurable adverse health effects from exposure to aerosolized Florida red tide toxins in persons with asthma. Future studies will examine the possible chronic effects of these toxins among persons with asthma and other chronic respiratory impairment.

Characterization of Red Tide Aerosol on the Texas Coast

The Gulf of Mexico red tide, caused by the dinoflagellate Karenia brevis (= Gymnodinium breve), occurs almost annually and has adverse economic and health effects. Exposure of people to sea spray containing aerosolized brevetoxins (PbTxs, polyether brevetoxins produced by K. brevis) causes irritation of the eyes, nose, and throat. Anecdotal reports suggest that exposed individuals can experience respiratory irritation and exacerbation of existing respiratory illnesses. There has been no systematic study of human exposure to red tide aerosols. In the fall of 2000, during a red tide episode on the Gulf Coast near Corpus Christi, Texas, we sampled at the Marine Science Institute (MSI) at Port Aransas on 25 October. Between 26-27 October we sampled at the Texas State Aquarium (TSA) near Corpus Christi. Two Hi-Vol samplers equipped with a filter and a five-stage impactor gave low concentrations of PbTxs, requiring us to develop methods to improve the minimum detection limit. An LC/MS/MS technique was used combining an HPLC and the API 365 MS/MS. PbTx-2 and PbTx-3 were detected at the TSA sampling location; however, PbTx was not detected in the samples from the MSI. The concentration of PbTx-2 was 1.5-4.9 ng m(-3) but was much lower for PbTx-3. The ratio of PbTx-2 to PbTx-3 was 8.7 +/- 5.2. During the highest exposure period (26-27 October), PbTx-6 was also detected. No one reported respiratory symptoms at the MSI, whereas at the TSA, several field study workers reported symptoms including nose and throat irritation, and itchy skin. A high-volume impactor was used to aerodynamically classify the particles into different size fractions. PbTx-2 was detected in all samples taken at the TSA; however, PbTx-3 was detected only between 26-27 October when the PbTx concentration was high. The mass median aerodynamic diameter (MMAD) was 7-9 mm with a relatively narrow size range (geometric standard deviation [GSD] about 1.6). In this study, much lower airborne concentrations of PbTx, 1.6-6.7 ng m(-3) were reported, along with a few incidents of upper respiratory symptoms. Although the number of seven workers was too small for statistical analysis, the reported symptoms were consistent with no to low exposure at the MSI and detectable exposures at the TSA. This suggests that at lower environmental concentrations of about 2-7 ng m(-3),exposure to PbTx could result in upper respiratory symptoms. This is consistent with the particle size measurement.

Characterization of plutonium aerosol collected during an accident

This study determined the plutonium particle size distribution and dissolution rate of PuO2 aerosol collected during the 16 March 2000 release of an undetermined amount of PuO2 in a room within a plutonium facility at Los Alamos National Laboratory. The facility has been in operation since 1978 to support the development, fabrication, and testing of Pu heat sources for the U.S. Department of Energy. Several workers were in the room at the time of the release and in vivo study of five of the workers began the day after the exposure event. Four of the subjects subsequently received chelation therapy. Over 30 fixed air filter samplers (FASs) and four continuous air monitors (CAMs) were operating in the room during the radiological release. One 47-mm-diameter glass fiber FAS filter and one 25-cm-diameter mixed cellulose ester CAM filter containing Pu aerosol from the incident were examined in the study described here. Total alpha radioactivity on the filters was determined by gross alpha counting. Isotopic identification of the Pu was made by alpha spectrometry. Film autoradiography was used to characterize the spatial distribution of alpha-emitting particles on the filters. Track-etch autoradiography was used to estimate the distribution of alpha radioactivity in individual plutonium particles on the filters for particle size measurement. The glass fiber filter was then cut into six sections. Particles from two sections were resuspended in alcohol, dispersed as an aerosol using a Lovelace nebulizer, and characterized by aerodynamic diameter using a Lovelace Multi-jet cascade impactor. The measured activity median aerodynamic diameter from the cascade impactor was 4.8 mum with a geometric standard deviation of 1.5. That agreed with the size distribution obtained from the alpha track detection technique. The remaining four filter sections were used in an in vitro dissolution study with synthetic serum ultrafiltrate. The retention of undissolved Pu was consistent with a biphasic exponential function. The majority of the Pu dissolved with a half-time of 900 d. The information on particle size distribution and solubility from this study was useful in assigning a radiation dose to the exposed workers, supporting the decision to administer chelation therapy, and providing a model for characterizing accident-associated aerosols in the future.