The impact of extraction methodologies on the toxicity of sediments in the zebrafish (Danio rerio) embryo test     

Hanno Zielke  Thomas-Benjamin Seiler  Sabine Niebergall  Erik Leist  Markus Brinkmann  Denise Spira  Georg Streck  Werner Brack  Ute Feiler  Thomas Braunbeck  Henner Hollert 《Journal of Soils and Sediments》2011,11(2):352-363

Purpose

Traditionally, methods for sediment extractions are characterised using chemical analyses. However, in order to evaluate sediment extracts with regard to biological effects and, thus, bioaccessibility, extraction methods have to be compared to effect data obtained from experiments with in situ exposure scenarios, i.e., sediment contact tests. This study compares four extraction methods and sediment contact test data from a previous project with respect to predictive power in the fish embryo test with zebrafish (Danio rerio).

Materials and methods

A natural and an artificial sediment spiked with a mixture of six organic pollutants (2,4-dinitrophenol, diuron, fluoranthene, nonylphenol, parathion and pentachlorophenol) were extracted using (a) membrane dialysis extraction (MDE), (b) a Soxhlet procedure, (c) hydroxypropyl-??-cyclodextrin (HPCD) or (d) Tenax^®-TA. Whereas the former two are regarded being exhaustive with respect to non-covalently bound contaminants, the latter two are considered to predict bioaccessibility. Resulting extracts were tested in the fish embryo assay with D. rerio for embryotoxic and teratogenic potential.

Results and discussion

Mortalities caused by organic extracts from Soxhlet extraction and MDE were high. However, HPCD extracts turned out to be at least as effective as extracts obtained with these two methods. One possible reason might be short ageing time of the spiked sediments. Only Tenax^®-TA extracts gave results comparable to the sediment contact assay for natural sediment, but revealed low reproducibility. Significant differences between natural and artificial sediment were found for extracts obtained with techniques using native (i.e., non-freeze-dried) sediments, i.e., HPCD and Tenax^®-TA. In contrast, MDE and Soxhlet extracts used freeze-dried sediment and did not differentiate between natural and artificial sediment. Therefore, freeze-drying has likely altered and equalised sediment properties that influence accessibility, such as composition of bacterial communities and organic matter quality.

Conclusions

Four extraction methods were successfully characterised with respect to their stringency and predictiveness for bioaccessibility. MDE was confirmed as an alternative to Soxhlet extraction. High mortalities induced by HPCD extracts underline the need to include ageing into consideration when assessing sediments. Although Tenax^®-TA may basically be used to predict bioaccessibility in the fish embryo test, the high variability observed warrants further investigation of the relation between effect and extractability. Apparently, freeze-drying can severely affect sediment properties, potentially eliminating individual properties of natural sediments.  相似文献   

The versatile,changing, and advancing roles of fish in sediment toxicity assessment—a review     

Arnold V. Hallare  Thomas-Benjamin Seiler  Henner Hollert 《Journal of Soils and Sediments》2011,11(1):141-173

Purpose  

Sediments serve as integral and dynamic parts of our aquatic systems. Within the last 15 to 20 years, however, the scientific community has begun noticing deterioration of sediment quality at an alarming rate worldwide. Sediments are now harboring hazardous pollutants that can directly influence water quality, thereby creating very stressful conditions for aquatic life. As a consequence, global efforts were initiated in the early 1970s, to find ways to assess sediment quality. Because of their obvious ecological and economic significance, fish have remained a major taxonomic group for appraising the general quality of aquatic systems. However, for sediment risk assessment, fish have lagged behind invertebrates due to their mobility and generally, pelagic lifestyle. To our knowledge, this is the first paper that comprehensively presents and reviews the versatile role of fish in assessing the state of health of aquatic sediments.  相似文献   

Embryo-Maternal Communication in Bovine – Strategies for Deciphering a Complex Cross-Talk     

E Wolf  GJ Arnold  S Bauersachs  HM Beier  H Blum  R Einspanier  T Fröhlich  A Herrler  S Hiendleder  S Kölle  K Prelle  H-D Reichenbach  M Stojkovic  H Wenigerkind  F Sinowatz 《Reproduction in domestic animals》2003,38(4):276-289

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STAGING OF LUMBAR INTER VERTEBRAL DISC DEGENERATION IN NONCHONDRODYSTROPHIC DOGS USING LOW-FIELD MAGNETIC RESONANCE IMAGING     

Gabriela  Seiler  Dr. Med. Vet.  Hansjürg  Häni  Dr. Med. Vet.  Jürg  Scheidegger  Dr. Med. FMH  André  Busato  Dr. Med. Vet. Habil  Johann  Lang  Dr. Med. Vet. Habil 《Veterinary radiology & ultrasound》2003,44(2):179-184

Recognition of disc degeneration in vivo is important in the investigation of the pathophysiology of intervertebral disc disease as well as the assessment of patients. The purpose of this study was to compare low-field magnetic resonance imaging and histopathologic findings of disc degeneration in the canine caudal lumbar spine. A simple four-stage classification system for disc degeneration is proposed. Most common signs of disc degeneration in magnetic resonance imaging included nuclear clefts, decreased signal intensity of the nucleus pulposus and tears of the annulus fibrosus, or disc herniations. The association between magnetic resonance images and histopathologic findings was highly significant. A sensitivity of 100% and specificity of 79% for magnetic resonance imaging was calculated using histopathology as the gold standard.  相似文献   

Growth promotants in cattle in Australia   总被引：2，自引：0，他引：2  

GJ SAWYER  DJ BARKER 《Australian veterinary journal》1988,65(4):101-108

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Gauge theories: progress in gauge field theory     

Seiler E 《Science (New York, N.Y.)》1985,230(4721):61-62

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Navigational ultrasound imaging: A novel imaging tool for aiding interventional therapies of equine musculoskeletal injuries          下载免费PDF全文

M. Lustgarten  W. R. Redding  L. V. Schnabel  T. Prange  G. S. Seiler 《Equine veterinary journal》2016,48(2):195-200

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Imaging diagnosis---jejunal vascular malformation in a dog     

Jennifer Kinns  Kirk Sears  Gabriela Seiler 《Veterinary radiology & ultrasound》2008,49(2):179-181

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Morphology of alpaca (Vicugna pacos) embryos in the first third of pregnancy          下载免费PDF全文

ANC Castro  MC Díaz  GJ Mendoza‐Torres  CA Llerena‐Zavala  MD Ghezzi  CG Barbeito 《Reproduction in domestic animals》2018,53(3):655-666

The breeding of South American camelids is the main economic activity of the high Andean region of South America and it, is potentially, the most profitable resource in of the Puna environmental conditions of the Puna. The duration of the gestation in alpaca is 339.7 ± 12 days. The objective of the present work was to macroscopically and microscopically describe the ontogenic development of the splanchnic cavities of the alpaca and to determine the gestational time in which the post‐cranial ossification centers are observed in the embryos/fetuses of this species, from day 21 to 107 of gestation. The documentation of normal ontogenic development, which is vacant for this period, is of the utmost importance to understand the consequences of the alterations at the different gestational times, as well as for the estimation of the gestational age in the case of abortions. Forty‐seven alpaca specimens of both sexes, at different times of their gestational development, collected during slaughter at local slaughterhouses of the Department of Huancavelica, Peru, were evaluated. Specimens were assigned to seven groups according to their morphological characteristics. The embryogenesis in the alpaca was characterized by a series of changes comparable to those occurring in other mammals with similar gestational periods. Despite these similarities, species differences were found in some organs as stomach, which are observed too in adult individuals.  相似文献   

Comparisons between elastographic stiffness scores for benign versus malignant lymph nodes in dogs and cats          下载免费PDF全文

Gabriela S. Seiler  Emily Griffith 《Veterinary radiology & ultrasound》2018,59(1):79-88

Lymph node evaluation is an important component of oncology staging in dogs and cats, however diagnosis of malignancy currently requires cytology or histopathology. Elastography is an ultrasound technique that allows estimation of tissue stiffness. In people, it has been shown to increase the sensitivity of sonography in detection of metastatic lymph nodes. The objective of this prospective, cross‐sectional study was to determine if elastographic stiffness differs for malignant versus benign canine and feline lymph nodes that were considered abnormal in gray‐scale ultrasound imaging. Animals scheduled for ultrasound‐guided fine needle aspirates of a lymph node at a single center were prospectively enrolled. Elastography was performed by a board‐certified veterinary radiologist (G.S.) prior to tissue sampling. Softness was scored qualitatively as 1–4 (1 = hard; 4 = soft) on an image depicted by a color scale (blue = hard, red = soft). Quantitative analysis was performed using custom‐made software. Fifty‐one lymph nodes were included in the evaluation, 21 had benign and 30 had neoplastic cytology. Benign lymph nodes were softer (median score of 2.5, range 1–4) than malignant lymph nodes (median = 2, range 1–3), and differences were significant in qualitative and quantitative analyses (P < 0.01). Of the lymph nodes with a score of 2 or below (hard), 19/25 (76%) were malignant, of the lymph nodes with a score over 2 (soft), 24/36 (67%) were benign. Findings indicated that elastographic stiffness scores differed between benign and malignant lymph node groups; however overlapping scores for the two groups limited the use of this technique for routine clinical diagnosis of malignancy.  相似文献