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We report two Australian patients with soft tissue infections due to Photorhabdus species. Recognized as important insect pathogens, Photorhabdus spp. are bioluminescent gram-negative bacilli. Bacteria belonging to the genus are emerging as a cause of both localized soft tissue and disseminated infections in humans in the United States and Australia. The source of infection in humans remains unknown.  相似文献   

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Hydraulically connected wetland microcosms vegetated with either Typha latifolia or Myriophyllum aquaticum were amended with an NH4NO3 and permethrin mixture to assess the effectiveness of both plant species in mitigating effects of the pollutant mixture on phytoplankton (as chlorophyll a) and Hyalella azteca. Phytoplankton grew in response to increased NH4NO3 in the presence of all plant species, but was unaffected by exposure to permethrin. H. azteca responses occurred rapidly (0.17 days), was mitigated within 1–2 days, and aqueous toxicity was unaffected by plant species type. A toxic unit model approach ascertained primary toxicity was permethrin with minimal additional toxicity from NH4NO3. Varying aquatic plant species had only modest influences on phytoplankton responses and no observable influence on animal responses during nitrogen-permethrin mixture exposures. As a result, both T. latifolia and M. aquaticum can be used as part of an effective agricultural best-management practice system for mitigating pollutant impacts of agricultural run-off.  相似文献   

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To partially simulate conditions in fish intestinal tracts, we leached six groups of metals-contaminated invertebrates at pH 2 and pH 7, and analyzed the concentrations of four metals (Cd, Cu, Pb, and Zn) and total protein in the leachates. Four of the groups of invertebrates were benthic macroinvertebrates collected from metals-contaminated rivers (the Clark Fork River in Montana and the Coeur d’Alene River in Idaho, USA); the other two groups of invertebrates (one of which was exposed to metals in the laboratory) were laboratory-reared brine shrimp (Artemia sp.). Additionally, we fractionated the pH 2 leachates using size-exclusion chromatography (SEC). Protein content was 1.3 to 1.4× higher in Artemia than in the benthic macroinvertebrates, and leachability of metals and protein differed considerably among several of the groups of invertebrates. In SEC fractions of the pH 2 leachates from both groups of Artemia, Cu and protein co-eluted; however, Cu and protein did not co-elute in SEC fractions of the leachates from any of the benthic macroinvertebrate groups. Although none of the other three metals co-eluted with protein in any of the pH 2 leachates, one or more of the metals co-eluted with lower-molecular-weight molecules in the leachates from all of the groups of invertebrates. These results suggest fundamental differences in metal-binding properties and protein leachability among some invertebrates. Thus, different invertebrates and different histories of metals exposure might lead to different availability of metals and protein to predators.  相似文献   

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The toxicity of the pyrethroid insecticide -cyhalothrin to freshwater invertebrates has been investigated using data from short-term laboratory toxicity tests and in situ bioassays and population-level effects in field microcosms. In laboratory tests, patterns of toxicity were consistent with previous data on pyrethroids. The midge Chaoborus obscuripes was most sensitive (48- and 96-h EC50 = 2.8 ng/L). Other insect larvae (Hemiptera, Ephemeroptera) and macrocrustacea (Amphipoda, Isopoda) were also relatively sensitive, with 48- and 96-h EC50 values between 10 and 100 ng/L. Generally, microcrustacea (Cladocera, Copepoda) and larvae of certain insect groups (Odonata and Chironomidae) were less sensitive, with 48-h EC50 values higher than 100 ng/L. Mollusca and Plathelminthes were insensitive and were unaffected at concentrations at and above the water solubility (5 g/L). Generally, the EC50 values based on initial population responses in field enclosures were similar to values derived from laboratory tests with the same taxa. Also, the corresponding fifth and tenth percentile hazard concentrations (HC5 and HC10) were similar (laboratory HC5 = 2.7 ng/L and field HC5 = 4.1 ng/L; laboratory and field HC10 = 5.1 ng/L), at least when based on the same sensitive taxonomic groups (insects and crustaceans) and when a similar concentration range was taken into account. In the three field enclosure experiments and at a treatment level of 10 ng/L, consistent effects were observed for only one population (Chaoborus obscuripes), with recovery taking place within 3 to 6 weeks. The laboratory HC5 (2.7 ng/L) and HC10 (5.1 ng/L) based on acute EC50 values of all aquatic arthropod taxa were both lower than this 10 ng/L, a concentration that might represent the regulatory acceptable concentration. The HC5 and HC10 values in this study in The Netherlands (based on static laboratory tests with freshwater arthropods) were very similar to those derived from a previous study in the United Kingdom (1.4 and 3.3 ng/L). This suggests that for pesticides like -cyhalothrin, HC5 values based on static laboratory tests may provide a conservative estimate of the potential for community-level effects under field conditions. While these HC5 values are conservative for initial effects, they do not provide information on recovery potential, which may be important for regulatory decision-making.  相似文献   

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INTRODUCTION: The study of the seasonal fluctuation, nocturnal activity, relative abundance and the richness of Anopheles species in anthropic environment is essential to the understanding of the their bioecology and to the surveillance program of malaria control. METHODS: The Anopheles species were studied from 6 P.M. to 6 A.M., once a month, for one year, from October 1996 to September 1997, in the municipal district of Raposa, of the S?o Luís island, Maranh?o state. The basic method was the capture of female specimens on human baits in peri and intradomicile sites by means of aspiration tube and guided luminous focus. RESULTS: A total of 1.407 specimens were collected and distributed as follow: Anopheles aquasalis (82% of the sample), Anopheles galvaoi (10,2%), Anopheles albitarsis (6,4%), Anopheles evansae, Anopheles nuneztovari, and Anopheles triannulatus davisi (the last three represented together 1, 4%). The anophelines occurred all year round, mainly in the rainy period, being more frequent in the intra (75,3%) than in the peridomicile site (24,7%), showing a clear preference to suck blood in the evening. CONCLUSION: The behavioural variation of Anopheles shows that the different species are becoming adapted to closeness to human habitations, in the rural zone of the S?o Luis island.  相似文献   

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Background: Chronic high arsenic exposure is associated with squamous cell carcinoma (SCC) of the skin, and inorganic arsenic (iAs) metabolites may play an important role in this association. However, little is known about the carcinogenicity of arsenic at levels commonly observed in the United States.Objective: We estimated associations between total urinary arsenic and arsenic species and SCC in a U.S. population.Methods: We conducted a population-based case–control SCC study (470 cases, 447 controls) in a U.S. region with moderate arsenic exposure through private well water and diet. We measured urinary iAs, monomethylarsonic acid (MMA), and dimethylarsinic acid (DMA), and summed these arsenic species (ΣAs). Because seafood contains arsenolipids and arsenosugars that metabolize into DMA through alternate pathways, participants who reported seafood consumption within 2 days before urine collection were excluded from the analyses.Results: In adjusted logistic regression analyses (323 cases, 319 controls), the SCC odds ratio (OR) was 1.37 for each ln-transformed microgram per liter increase in ln-transformed ΣAs concentration [ln(ΣAs)] (95% CI: 1.04, 1.80). Urinary ln(MMA) and ln(DMA) also were positively associated with SCC (OR = 1.34; 95% CI: 1.04, 1.71 and OR = 1.34; 95% CI: 1.03, 1.74, respectively). A similar trend was observed for ln(iAs) (OR = 1.20; 95% CI: 0.97, 1.49). Percent iAs, MMA, and DMA were not associated with SCC.Conclusions: These results suggest that arsenic exposure at levels common in the United States relates to SCC and that arsenic metabolism ability does not modify the association.Citation: Gilbert-Diamond D, Li Z, Perry AE, Spencer SK, Gandolfi AJ, Karagas MR. 2013. A population-based case–control study of urinary arsenic species and squamous cell carcinoma in New Hampshire, USA. Environ Health Perspect 121:1154–1160; http://dx.doi.org/10.1289/ehp.1206178  相似文献   

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Although octopuses are in high-demand globally and can bioaccumulate high concentrations of metals, the risk associated to its consumption is poorly understood. We compiled literature data from eight locations in Europe, North America and Northern Africa with different environmental levels of metals to evaluate: (1) the risk to human health through consumption of muscle tissues and digestive glands of Octopus hubbsorum, O. vulgaris and Eledone cirrhosa, and (2) the maximum allowable consumption rates (CRlim). The assessments were done according the United States Environmental Protection Agency. The results indicate the absence of health risk through consumption of muscle tissues, and high health risk through consumption of digestive glands (attributed to its high Cd levels), reflected in its 1ow CRlim values. In conclusion, even in contaminated sites the consumption of octopus muscle tissues is not an issue of concern, while the consumption of digestive glands should be more carefully monitored to avoid health problems.  相似文献   

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This study investigated the sensitivity of plant species to acid rain based on the modeled dosage-response relationship on the net photosynthetic rate (P (N)) of 21 types of plant species, subjected to the exposure of simulated acid rain (SAR) for 5 times during a period of 50 days. Variable responses of P (N) to SAR occurred depending on the type of plant. A majority (13 species) of the dosage-response relationship could be described by an S-shaped curve and be fitted with the Boltzmann model. Model fitting allowed quantitative evaluation of the dosage-response relationship and an accurate estimation of the EC(10), termed as the pH of the acid rain resulting in a P (N) 10 % lower than the reference value. The top 9 species (Camellia sasanqua, Cinnamomum camphora, etc. EC(10) ≤ 3.0) are highly endurable to very acid rain. The rare, relict plant Metasequoia glyptostroboides was the most sensitive species (EC(10) = 5.1) recommended for protection.  相似文献   

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This study was performed to investigate the heavy metal concentrations in muscle, liver, gill and intestine of six ray species from ?skenderun Bay. The present study is the first for rays in ?skenderun Bay, providing valuable preliminary information about heavy metal contents in different tissues of the examined ray species from the bay, and indirectly, indicating the environmental contamination of ?skenderun Bay. Heavy metal levels in intestines were generally higher than those in other tissues for all species. Metal levels in ray muscle tissue were below the international maximum allowable levels for fish and fishery products, as well as Turkish national guidelines, with the exception of the highest value for Cd in Dasyatis pastinaca.  相似文献   

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Organic carbon (OC) and elemental carbon (EC) in PM2.5 were estimated to study the seasonal and inter-annual variability of atmospheric total carbonaceous aerosols (TCA) at an urban site of megacity Delhi, India for 5 years from January, 2012 to December, 2016. The annual average (±?standard deviation) concentrations of PM2.5, OC, EC and TCA were 128?±?81, 16.6?±?12.2, 8.4?±?5.8 and 34.5?±?25.2 µg m?3, respectively. During the study, significant seasonal variations in mass concentrations of PM2.5, OC, EC and TCA were observed with maxima in winter and minima in monsoon seasons. Significant correlations between OC and EC, and OC/EC ratio suggested that vehicular emissions, fossil fuel combustion and biomass burning could be major sources of carbonaceous aerosols of PM2.5 at the sampling site of Delhi, India.  相似文献   

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A gram-negative, rod-shaped microorganism was detected in a 69-year-old man suffering from chronic back pain but otherwise exhibiting no signs of infection. The bacterium could not be identified using any routine diagnostic modality. A research use only application utilizing PCR and Mass Spectrometry* was performed on nucleic acid extracted from the tissue sample. These studies resulted in the implication of Bartonella quintana as the underlying cause of the infection. B. quintana is not a well-known cause of an abdominal aortic mycotic aneurysm. This article will discuss the B. quintana infection, its diagnosis and treatment, and reinforce the potential of B. quintana as a possible etiology in mycotic aneurysms that show no apparent indications of infection. It will also explore the potential use of polymerase chain reaction detected by electrospray ionization mass spectrometry (PCR/ ESI-MS) to help identify B. quintana in a situation where other conventional methods prove non-informative.  相似文献   

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This paper presents the levels of lead found in the feathers of adult and blood of nestlings of booted eagle (Hieraaetus pennatus), European buzzard (Buteo buteo), and goshawk (Accipiter gentilis) sampled in the 1999 and 2000 breeding seasons in a Mediterranean forest of the Province of Murcia (Southeastern Spain) located far from potential sources of metal contamination. Levels of -aminolevulinic acid dehydratase activity (-ALAD) in blood were also measured in the nestlings. Lead concentrations ranged from 1.1 to 11.21 g/dl in blood of nestlings and from 0.35 to 1.66 mg/kg d.w. in the feathers of their parents. A significant relationship was found between blood -ALAD and lead ( = –568), showing a negative correlation with blood lead levels even at lead concentrations below 5 g/dl. This fact suggests the usefulness of this enzymatic biomarker for low lead exposure in forest raptors. There were also positive relationships between the lead concentrations in blood of nestlings and those in feathers of their parents ( = 0.817), suggesting the usefulness of feathers for biomonitoring environmental exposure to lead.  相似文献   

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We aimed to evaluate the elemental (W, Mo, Zn, Fe, Cu, Co, Bi, Mn, Cd, Cr, As) composition of some plant species spread around the abandoned tungsten mining area of Uluda? Mountain. The plant species tested were Anthemis cretica and Trisetum flavescens which are grown in this area and they are pioneer species on these contaminated sites. W levels in soils were found up to 1378.6 ± 672.3 mg/kg dry weight in contaminated areas. The leaf W contents of the selected plant species were found 41.1 ± 24.4 and 31.1 ± 15.5 mg/kg dry weight for A. cretica and T. flavescens, respectively. Our results indicate that the elemental composition of species changed by the increased tungsten and some element concentrations in soil without detrimental effect. So, these species can be useful tungsten removal and some elements from contaminated sites.  相似文献   

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This study was performed to investigate certain major and toxic metal concentrations in muscle, gill and liver tissues of two Cyprinid species (Leuciscus cephalus, Tinca tinca). Generally liver and gill tissue exhibited higher metal concentrations than did muscle. The highest metal concentrations found in tench and chub muscle tissues were determined to be Al (59.01–108 mg kg−1), Zn (45.23–57.81 mg kg−1), Fe (9.23–16.03 mg kg−1) and Ba (3.50–2.69 mg kg−1) respectively. The level of metal accumulation is evaluated for potential risk to human health based on international standards. Zinc, lead and arsenic values of muscle tissues of the fishes were found to be above the allowed limits for human consumption.  相似文献   

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Bulletin of Environmental Contamination and Toxicology - In ecotoxicological assays, previously selected and standardized organism tests are exposed to an environmental sample. Some species of the...  相似文献   

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