bluuebunny/crossref_metadata_2025_split huggingface dataset:
Differential resistance to copper and mine drainage inDaphnia longispina: Relationship with allozyme genotypes
Authors: Martins Nelson , Lopes Isabel , Harper Ruth Maureen , Ross Philippe , Ribeiro Rui 
Published: August 2007

AbstractDifferential resistance to metal pollution in Daphnia longispina populations was reported in previous studies. In this work, we tried to determine if variation in polymorphic enzymes, often referred as being under metal selection, were related with differences in resistance to acute single- and mixed-metal exposure. Allozyme genotype of 20 putatively polymorphic enzymes, 48-h median lethal concentration (LC50) for copper, and median lethal time (LT50) for a 3% dilution of acid mine drainage (AMD) were determined for 24 lineages of D. longispina. The copper LC50s ranged from 29.3 to 226 μg/L, and the AMD LT50s ranged from 48 min to 25 h and 29 min, with a strong correlation between both end points. Five distinct multilocus genotypes were identified based on polymorphisms in glucose-6-phosphate isomerase, lactate dehydrogenase, malate dehydrogenase, nicotinamide adenine dinucleotide phosphate (NADP+), phosphoglucomutase, and peroxidase. No differences were found in average genotype sensitivity for both toxicity end points or in genotype frequencies between the resistant- and sensitive-lineage groups. The results obtained indicate that allozyme genotype is not associated with increased resistance to acute metal stress in D. longispina.
Tamoxifen protects against 17α-ethynylestradiol-induced liver damage and the development of urogenital papillae in the rainbow darter (Etheostoma caeruleum)
Authors: Elias Eric Edward , Kalombo Eddie , Mercurio Steven Don 
Published: August 2007

AbstractJuvenile rainbow darters (Etheostoma caeruleum) were exposed to nominal concentrations of 20 to 1,000 ng/L of 17α-ethynylestradiol (EE2) at 120 d posthatch and in a subsequent experiment to 200 ng/L of EE2 with 2.0 to 20,000 ng/L of tamoxifen (TMX) at 150 d posthatch to determine the threshold of estrogen-induced morphological and histological changes in a sexually dimorphic benthic fish species ecologically relevant to southern Minnesota (USA). 17α-Ethynylestradiol induced female-associated urogenital papillae in males at 200 ng/L, enlargement and development of fibrosis in male testes, enlargement of ovary and oocyte size in females, and large fatty inclusions in the liver of both sexes. Exposure to 1,000 ng/L of EE2 caused gross hypertrophy of the liver and kidneys and high mortalities, predominantly in male fish. A low incidence of ovotestes found in all treatment groups was unaffected by EE2, which may be unusual to this species or a response to unknown water contaminants present during the hatching or early development of the darters. Gonadosomatic index was not altered for either sex by any treatment. A TMX level equal to or less than that of EE2 decreased fat accumulation in the liver in both sexes, and a TMX level greater than that of EE2 appeared to prevent urogenital papilla in males. Tamoxifen did not significantly alter fibrosis caused by EE2 in testes. It appears that the presence of TMX in the environment can mask many signs of estrogen exposure, including secondary sexual characteristics, hypertrophy of ovaries and testes, and fatty infiltration of organs. Ovotestes did not prove to be a good indicator of estrogen exposure at this late stage of juvenile darter development.
In situ and laboratory bioassays withChironomus ripariuslarvae to assess toxicity of metal contamination in rivers: The relative toxic effect of sediment versus water contamination
Authors: Faria Mafalda S. , Lopes Ricardo J. , Nogueira António J.A. , Soares Amadeu M.V.M. 
Published: August 2007

AbstractWe used bioassays employing head capsule width and body length increase of Chironomus riparius larvae as end points to evaluate metal contamination in streams. Bioassays were performed in situ near an abandoned Portuguese goldmine in the spring of 2003 and 2004. Bioassays also were performed under laboratory conditions with water and sediment collected from each stream to verify if laboratory bioassays could detect in situ toxicity and to evaluate the relative contribution of sediment and water to overall toxicity. We used field sediments with control water and control sediments with field water to discriminate between metal contamination in water and sediment. Field water with dry and sieved, organic matter–free, and nontreated sediments was used to determine the toxicity of heavy metals that enter the organism through ingested material. In both in situ and laboratory bioassays, body length increase was significantly inhibited by metal contamination, whereas head capsule width was not affected. Body length increase was more affected by contaminated sediment compared to contaminated water. The lowest-effect level of heavy metals was observed in the dry and sieved sediment that prevented ingestion of sediment particles by larvae. These results suggest that body length increase of C. riparius larvae can be used to indicate the impact of metal contamination in rivers. Chironomus riparius larvae are more affected by heavy metals that enter the organism through ingested sediment than by heavy metals dissolved in the water column. Nevertheless, several factors, such as the particle size and organic matter of sediment, must be taken into account.
Competitive binding comparison of endocrine-disrupting compounds to recombinant androgen receptor from fathead minnow, rainbow trout, and human
Authors: Wilson Vickie S. , Cardon Mary C. , Gray L. Earl , Hartig Phillip C. 
Published: August 2007

AbstractTypically, in vitro hazard assessments for the identification of endocrine-disrupting compounds (EDCs), including those outlined in the Endocrine Disruptor Screening and Testing Advisory Committee (EDSTAC) Tier 1 Screening protocols, utilize mammalian receptors. Evidence, however, exists that fish sex steroid hormone receptors differ from mammalian receptors both structurally and in their binding affinities for some steroids and environmental chemicals. Most of the binding studies to date have been conducted using cytosolic preparations from various tissues. In the present study, we compare competitive binding of a set of compounds to full-length recombinant rainbow trout androgen receptor α (rtAR), fathead minnow androgen receptor (fhAR), and human androgen receptor (hAR), each expressed in COS cells. Saturation binding and subsequent Scatchard analysis using [3H]R1881, a high-affinity synthetic androgen, revealed an equilibrium dissociation constant (Kd) of 0.11 nM for the rtAR, 1.8 nM for the fhAR, and 0.84 nM for the hAR. Compounds, including endogenous and synthetic steroids, known mammalian antiandrogens, and environmental compounds, were tested for competitive binding to each of the three receptors. Overall, agreement existed across receptors as to binding versus nonbinding for all compounds tested in this study. Minor differences, however, were found in the relative order of binding of the compounds to the individual receptors. Studies such as these will facilitate the identification of EDCs that may differentially affect specific species and aid in the development and support of future risk assessment protocols.
Bayesian multimodel inference for dose-response studies
Authors: Link William A. , Albers Peter H. 
Published: August 2007

Abstract
Statistical inference in dose—response studies is model-based: The analyst posits a mathematical model of the relation between exposure and response, estimates parameters of the model, and reports conclusions conditional on the model. Such analyses rarely include any accounting for the uncertainties associated with model selection. The Bayesian inferential system provides a convenient framework for model selection and multimodel inference. In this paper we briefly describe the Bayesian paradigm and Bayesian multimodel inference. We then present a family of models for multinomial dose—response data and apply Bayesian multimodel inferential methods to the analysis of data on the reproductive success of American kestrels (Falco sparveriuss) exposed to various sublethal dietary concentrations of methylmercury.
Recovery of cholinesterase activity in the earthworm Eisenia fetida Savigny following exposure to chlorpyrifos
Authors: Aamodt Solveig , Konestabo Heidi Sjursen , Sverdrup Line Emilie , Gudbrandsen Marius , Reinecke Sophiè A. , Reinecke Adriaan J. , Stenersen Jørgen 
Published: August 2007

Abstract
Organophosphorus (OP) insecticides inhibit cholinesterase activity, an essential process in the nervous system of most animals. Re-establishment of active enzymes is slow and depends on elimination of the insecticide from the body followed by two lengthy processes: Reactivation and/or biosynthesis of new enzymes. Earthworms (Eisenia fetida) were exposed to either clean or chlorpyrifos-containing (240 mg/kg) soil for 48 h. After transfer to clean soil, we monitored two cholinesterases (E1 and E2) and chlorpyrifos content of the earthworms for 12 weeks. After 14 to 21 d of recovery, the exposed and control worms were indistinguishable in terms of appearance and behavior. Chemical analysis showed a rapid elimination of chlorpyrifos from the earthworms, with only minor levels detected after one week. The activities of E1 and E2 were measured spectrophotometrically in whole specimen homogenates using acetylthiocholine as the substrate. Carbaryl, which selectively inhibits E1, was used to discriminate the enzyme activities. Mean ± standard error of mean of E1 and E2 activity in the controls immediately after exposure were 1.57 ± 0.18 nanokatal (nkat)/mg protein (n = 3) and 0.95 ± 0.07 nkat/mg protein, respectively, and 0.48 ± 0.07 nkat/mg and 0.45 ± 0.06 nkat/mg, respectively, in exposed worms. After three weeks, E1 had regained an activity comparable to the controls, whereas E2 remained depressed throughout the 12-week monitoring period. The non- or late recovery of E2 makes this enzyme a potential biomarker candidate for previous OP insecticide exposure in Eisenia fetida, provided the protocol for measurements is improved and standarized.
3-Methyl-4-nitrophenol metabolism by uridine diphosphate glucuronosyltransferase and sulfotransferase in liver microsomes of mice, rats, and Japanese quail (Coturnix japonica)
Authors: Lee Chul-Ho , Kamijima Michihiro , Li ChunMei , Taneda Shinji , Suzuki Akira K. , Nakajima Tamie 
Published: August 2007

Abstract
3-Methyl-4-nitrophenol (PNMC) is a component of diesel exhaust particles and one of the major breakdown products of the insecticide fenitrothion. This chemical has a high potential for reproductive toxicity in Japanese quail (Coturnix japonica) and rats. Because PNMC inhaled by the body is metabolized by uridine diphosphate glucuronosyltransferase (UGT) and sulfo-transferase, we investigated these enzyme activities in the hepatic microsomes and cytosols of quail (as a model of wild birds) and compared these activities with those of rats and mice as models of ecological and human risk assessment. The maximum velocity of the UGT for PNMC in quail was 12.7 nmol/min/mg, which was one third and one fourth those of rats and mice, respectively. The Michaelis–Menten constant of UGT for PNMC in quail was 0.29 mM, which was 1.3- and 1.8-fold higher than that in mice and rats, respectively, but not significantly different. In accordance with these results, UGT activities for PNMC were lowest in quail, with those in mice and rats being 4.4- and 2.7-fold higher, respectively. Sulfotransferase activity for PNMC was considerably less than that of UGT in all animals, including quail; no significant differences in the activities were found among mice, rats, and quail. These results suggest that glucuronidation may be involved primarily in PNMC elimination from wild birds as well as mammals and that the UGT activity in quail is less than that in the rodents.
Acute toxicity of sodium nitrate, potassium nitrate, and potassium chloride and their effects on the hemolymph composition and gill structure of early juvenile blue swimmer crabs (Portunus pelagicus Linnaeus, 1758) (decapoda, brachyura, portunidae)
Authors: Romano Nicholas , Zeng Chaoshu 
Published: August 2007

Abstract
Various nutrients, including K+ and NO−3, are increasingly being discharged into aquatic systems via anthropogenic sources, which may impact marine organisms. The present study was conducted on blue swimmer crab (Portunus pelagicus) early juveniles to determine the acute toxicity of NaNO3, KNO3, and KCl; if a toxicity interaction exists between K+ and NO−3; the hemolymph Na+, K+, and Ca2+ changes; and the gill histopathological alterations following exposure to elevated NaNO3, KNO3, and KCl levels. A total of 20 replicate crabs were exposed to each of the five NaNO3, KNO3, and KCl concentrations for 96 h. After 96 h, the surviving crabs were sampled for hemolymph Na+, K+, and Ca2+ levels and fixed for histological examination of the anterior gills. The 96-h median lethal concentration of NaNO3-N, KNO3-N, KNO3-K, and KCl-K was 3,452, 112, 312, and 356 mg/L, respectively, for early P. pelagicus juveniles. The toxicity of NaNO3-N was significantly less (p &lt; 0.01) than that of KNO3-N. Furthermore, at the same K+ levels, KNO3-K was significantly (p &lt; 0.05) more toxic than KCl-K, indicating a toxicity interaction between K+ and NO−3. Following exposure to elevated KNO3 and KCl levels, the crabs had significantly higher (p &lt; 0.01) hemolymph K+ levels compared to the control. Conversely, following exposure to elevated NaNO3 concentrations, the crabs had significantly higher (p &lt; 0.01) hemolymph Na+ levels but significantly lower (p &lt; 0.01) hemolymph K+ levels. Despite the markedly different hemolymph ionic changes following NaNO3 and KNO3/KCl exposure, the histopathological changes to the anterior gill lamellae of the crabs appeared to be similar, including lamellae swelling, epithelial thickening, pillar cell disruption, necrosis, and distortion.
Climate change and the EU Water Framework Directive: how to deal with indirect effects of changes in hydrology on water quality and ecology?
Authors: ter Heerdt G.N.J. , Schep S.A. , Janse J.H. , Ouboter M. 
Published: August 2007

In order to set ecological goals and determine measures for the European Water Framework Directive, the effects of climate change on lake ecosystems should be estimated. It is thought that the complexity of lake ecosystems makes this effect inherently unpredictable. However, models that deal with this complexity are available and well calibrated and tested. In this study we use the ecosystem model PCLake to demonstrate how climate change might affect the ecological status of a shallow peaty lake in 2050.
With the model PCLake, combined with a long-term water and nutrient balance, it is possible to describe adequately the present status of the lake. Simulations of future scenarios with increasing precipitation, evaporation and temperature, showed that climate change will lead to higher nutrient loadings. At the same time, it will lead to lower critical loadings. Together this might cause the lake to shift easier from a clear water to a turbid state. The amount of algae, expressed as the concentration Chl-a, will increase, as a consequence turbidity will increase. The outcome of this study; increasing stability of the turbid state of the lake, and thus the need for more drastic measures, is consistent with some earlier studies.
Maxillary and Mandibular Dentoalveolar Heights of French-Canadians 10 to 15 Years of Age
Authors: Buschang Peter H. , Carrillo Roberto , Liu Sean S. , Demirjian Arto 
Published: August 2007

Abstract
Objective: To establish reference data for anterior and posterior dentoalveolar heights of growing French-Canadians with untreated normal occlusions and malocclusions.
Materials and Methods: The mixed longitudinal sample includes 227 French-Canadians, 119 male and 108 female, with cephalograms taken annually between 10–15 years of age. Maxillary and mandibular dentoalveolar heights were measured as the perpendicular distances of the incisor tips and first molar mesial cusp tips to the palatal (ANS-PNS) and mandibular (Go-Me) planes.
Results: Male dentoalveolar heights were significantly (P &lt; .05) greater than female heights at all ages. Dentoalveolar heights at 15 years of age were significantly larger (P &lt; .05) than at 10 years of age, with differences ranging from 2.1–4.2 mm in male subjects and from 2.1–3.8 mm in female subjects. The greatest difference in dentoalveolar heights between the 10- and 15-year-old age groups was for the maxillary first molar; the maxillary central incisor height showed the smallest age effects. The coefficients of variation were greater for the maxillary than the mandibular dentoalveolar heights. Correlations of dentoalveolar heights within jaws ranged from 0.53 to 0.82; correlations between jaws ranged from 0.30 to 0.44. The mandibular heights showed the strongest associations.
Conclusions: French-Canadian adolescents require age- and sex-specific reference data for dentoalveolar heights.
Influence of Surface Characteristics on Survival Rates of Mini-Implants
Authors: Chaddad Karim , Ferreira AndréF. H. , Geurs Nico , Reddy Michael S. 
Published: August 2007

Abstract
Objective: To compare the clinical performance and the survival rate of two mini-implant systems with different surface characteristics under immediate orthodontic loading.
Materials and Methods: Seventeen machined titanium (MT) mini-implants and 15 sandblasted, large grit, acid-etched (SLA) mini-implants were placed in 10 patients. The mini-implants were immediately loaded and the patients seen at 7, 14, 30, 60, and 150 days. Clinical parameters such as anatomical location, character of the soft tissue at the screw head emergence, type of mini-implant system, diameter, and length were analyzed. In addition, the insertion torque recorded at the time of insertion was also assessed. Survival rate and clinical parameters were evaluated by the chi-square exact tests using the SAS version 9.1.
Results: The overall survival rate was 87.5%. Over the four failing mini-implants, three were MT and one SLA resulting in an individual survival rate of 82.4% and 93.4%, respectively. In the failure group, all the fixtures had their screw emergence at the oral mucosa and recorded a torque range of less than 15 Ncm. The insertion torque statistically influenced the survival rate of the mini-implants (P &lt; .05). Surface treatment, anatomical location, as well as soft tissue emergence were not statistically significant.
Conclusion: Surface characteristics did not appear to influence survival rates of immediately loaded mini-implants.
Automatic Cephalometric Analysis
Authors: Leonardi Rosalia , Giordano Daniela , Maiorana Francesco , Spampinato Concetto 
Published: August 2007

Abstract
Objective: To describe the techniques used for automatic landmarking of cephalograms, highlighting the strengths and weaknesses of each one and reviewing the percentage of success in locating each cephalometric point.
Materials and Methods: The literature survey was performed by searching the Medline, the Institute of Electrical and Electronics Engineers, and the ISI Web of Science Citation Index databases. The survey covered the period from January 1966 to August 2006. Abstracts that appeared to fulfill the initial selection criteria were selected by consensus. The original articles were then retrieved. Their references were also hand-searched for possible missing articles. The search strategy resulted in 118 articles of which eight met the inclusion criteria. Many articles were rejected for different reasons; among these, the most frequent was that results of accuracy for automatic landmark recognition were presented as a percentage of success.
Results: A marked difference in results was found between the included studies consisting of heterogeneity in the performance of techniques to detect the same landmark. All in all, hybrid approaches detected cephalometric points with a higher accuracy in contrast to the results for the same points obtained by the model-based, image filtering plus knowledge-based landmark search and “soft-computing” approaches.
Conclusions: The systems described in the literature are not accurate enough to allow their use for clinical purposes. Errors in landmark detection were greater than those expected with manual tracing and, therefore, the scientific evidence supporting the use of automatic landmarking is low.
Rabies surveillance in the United States during 2006
Authors: Blanton Jesse D. , Hanlon Cathleen A. , Rupprecht Charles E. 
Published: August 2007

Abstract
Summary—During 2006, 49 states and Puerto Rico reported 6,940 cases of rabies in animals and 3 cases in humans to the CDC, representing an 8.2% increase from the 6,417 cases in animals and 1 case in a human reported in 2005. Approximately 92% of the cases were in wildlife, and 8% were in domestic animals. Relative contributions by the major animal groups were as follows: 2,615 raccoons (37.7%), 1,692 bats (24.4%), 1,494 skunks (21.5%), 427 foxes (6.2%), 318 cats (4.6%), 82 cattle (1.2%), and 79 dogs (1.1%). Compared with numbers of reported cases in 2005, cases in 2006 increased among all groups except cattle. Increases in numbers of rabid raccoons during 2006 were reported by 11 of the 20 eastern states where raccoon rabies was enzootic, and reported cases increased by 3.2% overall, compared with 2005.
On a national level, the number of rabies cases in skunks during 2006 increased by 6.1% from the number reported in 2005. Once again, Texas reported the greatest number (n = 351) of rabid skunks and the greatest overall state total of animal rabies cases (889). No cases of rabies associated with the dog/coyote rabies virus variant were reported. The last identified case of this canine rabies virus variant was identified in March 2004, along the US/Mexi-co border. With 2006 marking the second year of no apparent transmission of the dog/coyote variant, these findings from surveillance data support the contention that the canine rabies virus variant is no longer in circulation in the United States. Total number of cases of rabies reported nationally in foxes increased 13.6%, compared with 2005. Increases in the number of reported rabid foxes were attributable to greater numbers of foxes reported with the Arctic fox rabies virus variant in Alaska, the Texas gray fox rabies virus variant in Texas, and the raccoon rabies virus variant in Virginia. The 1,692 cases of rabies reported in bats represented a 14.5% increase, compared with numbers reported in 2005, making bats the second most reported rabid animal behind raccoons. Cases of rabies in cats, dogs, horses and mules, and sheep and goats increased 18.2%, 3.9%, 12.8%, and 22.2%, respectively, whereas cases reported in cattle decreased 11.8%. In Puerto Rico, reported cases of rabies in mongooses increased 9.2%, and rabies in domestic animals, presumably attributable to spillover infection from mongooses, increased 20%.
Three cases of human rabies were reported from Texas, Indiana, and California during 2006. The cases in Indiana and Texas were attributed to bat rabies virus variants, whereas the case in California was attributed to an exposure to a dog in the Philippines.