Investigation of the developmental toxicity of cocaine in in vitro cultured chick embryos: Correlation of effects with intra-embryonic drug levels

1991 ◽  
Vol 5 (4) ◽  
pp. 285-293 ◽  
Author(s):  
G.J. Burin ◽  
L.K. Al-Ghaith ◽  
K.G. Anitole ◽  
M.K. Barber ◽  
K.M. Brown
Keyword(s):  
Developmental Toxicity ◽  
Chick Embryos ◽  
Drug Levels

The Bioavailability of Substances Administered to Chick Embryos: The Maximum Effective Route of Administration

1997 ◽  
Vol 25 (6) ◽  
pp. 655-665
Author(s):  
Drahomír Veselý ◽  
Doubravka Veselá ◽  
Richard Jelínek
Keyword(s):  
Palmitic Acid ◽  
Culture Media ◽  
Developmental Toxicity ◽  
Avian Embryo ◽  
In Vitro Test ◽  
Chick Embryos ◽  
Amount Of Substance ◽  
Mammalian Embryos ◽  
Concentration Curves

Toxicokinetic studies are of key importance in both the design and the interpretation of developmental toxicity studies. The aim of this study was to determine concentrations of test substances within the chick embryo following the administration schedule recommended in the chick embryotoxicity screening test (CHEST). The concentration-time relationships were investigated by using four labelled substances with various physicochemical and embryo-toxic properties ([14C] sodium acetate, [14C] palmitic acid, [3H] Cortisol and [3H] cytosine arabinoside). These labelled chemicals were mixed with cold substances and singly administered at two dose levels to chick embryos on days 2, 3 and 4 of incubation. Extrachorial and subgerminal routes were used on day 2, and extrachorial and intra-amniotic applications were chosen on days 3 and 4. The concentration of labelled chemical present within the embryo was assessed at predetermined intervals by scintillation fluorimetry (from 6 minutes to 96 hours after administration), and used for estimating the concentration curves. Regardless of the substance, dose and application route, the concentration curves exhibited a characteristic pattern, reaching their peaks within the first 6 hours, and dropping down to near zero 48–96 hours after administration. The decrease followed the first order law, demonstrating that, within the CHEST system, the avian embryo does not act as a closed system. With regard to the total amount of substance entering the embryo, extrachorial administration appeared to be superior to subgerminal administration on day 2. Intra-amniotic administration was superior to extrachorial administration on days 3 and 4. These differences were most pronounced after administration of lipid-soluble palmitic acid. The concentrations within embryonic tissues were directly dose-dependent. After consideration of all these findings, we concluded that the CHEST system probably has closer similarity to the toxicokinetics of exposure of mammalian embryos (i.e. reaching a peak and then a gradual decline over time) than any other in vitro test of developmental toxicity, where the chemical is simply added to culture media. Several practical recommendations for improving the CHEST system were derived.

The Use of Biomarkers as Alternatives to Current Animal Tests on Food Chemicals

1998 ◽  
Vol 26 (4) ◽  
pp. 421-480
Author(s):  
Krys Bottrill
Keyword(s):  
Animal Studies ◽  
Developmental Toxicity ◽  
Reproductive Toxicity ◽  
In Vitro Test ◽  
Animal Testing ◽  
Dietary Biomarkers ◽  
Recent Developments ◽  
Mechanistic Basis ◽  
The Three Rs

Recent developments in biomarkers relating to the interrelationship of diet, disease and health were surveyed. Most emphasis was placed on biomarkers of deleterious effects, since these are of greatest relevance to the subject of this review. The area of greatest activity was found to be that relating to biomarkers of mutagenic, genotoxic and carcinogenic effects. This is also one of the major areas of concern in considerations of the beneficial and deleterious effects of dietary components, and also the area in which regulatory testing requires studies of the longest duration. A degree of progress has also been made in the identification and development of biomarkers relating to certain classes of target organ toxicity. Biomarkers for other types of toxicity, such as immunotoxicity, neurotoxicity, reproductive toxicity and developmental toxicity, are less developed, and further investigation in these areas is required before a comprehensive biomarker strategy can be established. A criticism that recurs constantly in the biomarker literature is the lack of standardisation in the methods used, and the lack of reference standards for the purposes of validation and quality control. It is encouraging to note the growing acknowledgement of the need for validation of biomarkers and biomarker assays. Some validation studies have already been initiated. This review puts forward proposals for criteria to be used in biomarker validation. More discussion on this subject is required. It is concluded that the use of biomarkers can, in some cases, facilitate the implementation of the Three Rs with respect to the testing of food chemicals and studies on the effects of diet on health. The greatest potential is seen to be in the refinement of animal testing, in which biomarkers could serve as early and sensitive endpoints, in order to reduce the duration of the studies and also reduce the number of animals required. Biomarkers could also contribute to establishing a mechanistic basis for in vitro test systems and to facilitating their validation and acceptance. Finally, the increased information that could result from the incorporation of biomarker determinations into population studies could reduce the need for supplementary animal studies. This review makes a number of recommendations concerning the prioritisation of future activities on dietary biomarkers in relation to the Three Rs. It is emphasised, however, that further discussions will be required among toxicologists, epidemiologists and others researching the relationship between diet and health.

scholarly journals Predicting the in vivo developmental toxicity of benzo[a]pyrene (BaP) in rats by an in vitro–in silico approach

2021 ◽  
Author(s):  
Danlei Wang ◽  
Maartje H. Rietdijk ◽  
Lenny Kamelia ◽  
Peter J. Boogaard ◽  
Ivonne M. C. M. Rietjens
Keyword(s):  
Dose Response ◽  
In Silico ◽  
Response Curve ◽  
Developmental Toxicity ◽  
Toxicity Testing ◽  
Maximal Effect ◽  
Blood Concentrations ◽  
Reverse Dosimetry

AbstractDevelopmental toxicity testing is an animal-intensive endpoints in toxicity testing and calls for animal-free alternatives. Previous studies showed the applicability of an in vitro–in silico approach for predicting developmental toxicity of a range of compounds, based on data from the mouse embryonic stem cell test (EST) combined with physiologically based kinetic (PBK) modelling facilitated reverse dosimetry. In the current study, the use of this approach for predicting developmental toxicity of polycyclic aromatic hydrocarbons (PAHs) was evaluated, using benzo[a]pyrene (BaP) as a model compound. A rat PBK model of BaP was developed to simulate the kinetics of its main metabolite 3-hydroxybenzo[a]pyrene (3-OHBaP), shown previously to be responsible for the developmental toxicity of BaP. Comparison to in vivo kinetic data showed that the model adequately predicted BaP and 3-OHBaP blood concentrations in the rat. Using this PBK model and reverse dosimetry, a concentration–response curve for 3-OHBaP obtained in the EST was translated into an in vivo dose–response curve for developmental toxicity of BaP in rats upon single or repeated dose exposure. The predicted half maximal effect doses (ED50) amounted to 67 and 45 mg/kg bw being comparable to the ED50 derived from the in vivo dose–response data reported for BaP in the literature, of 29 mg/kg bw. The present study provides a proof of principle of applying this in vitro–in silico approach for evaluating developmental toxicity of BaP and may provide a promising strategy for predicting the developmental toxicity of related PAHs, without the need for extensive animal testing.

scholarly journals STUDIES OF THE DEGENERATION AND REGENERATION OF AXIS CYLINDERS IN VITRO

1913 ◽  
Vol 17 (2) ◽  
pp. 182-191 ◽  
Author(s):  
Ragnvald Ingebrigtsen
Keyword(s):  
Spinal Cord ◽  
Degenerative Changes ◽  
Spinal Ganglia ◽  
Chick Embryos

1. The brains of chick embryos, of cats six weeks old, of rabbits two months old, and of dogs three weeks old, when cultivated in vitro, develop long filaments which, according to their growth and their anatomical and tinctorial characters, must be considered as true axis cylinders. 2. Similar structures develop from spinal ganglia of rabbits seven months old, and from the spinal cord of cats six weeks old, and of rabbits two months old. 3. When severed from their origin by section these threads undergo degenerative changes which do not appear after nine hours, but which are seen after twenty hours, and continue until in the course of the following two days the thread degenerates completely. 4. After twenty hours the development of new axis cylinders from the central part of the cut fibers is observed.

Safety Assessment of a Hydroethanolic Extract of Caralluma fimbriata

2013 ◽  
Vol 32 (5) ◽  
pp. 385-394 ◽  
Author(s):  
Antoinette Y. Odendaal ◽  
Narendra S. Deshmukh ◽  
Tennille K. Marx ◽  
Alexander G. Schauss ◽  
John R. Endres ◽  
...  
Keyword(s):  
Developmental Toxicity ◽  
Toxicity Study ◽  
Developmental Study ◽  
Sprague Dawley ◽  
Oral Toxicity ◽  
Toxicological Assessment ◽  
Sprague Dawley Rats ◽  
Chromosomal Aberration Test ◽  
Hydroethanolic Extract

This toxicological assessment evaluated the safety of a hydroethanolic extract prepared from Caralluma fimbriata (CFE), a dietary supplement marketed worldwide as an appetite suppressant. Studies included 2 in vitro genotoxicity assays, a repeated dose oral toxicity study, and a developmental study in rats. No evidence of in vitro mutagenicity or clastogenicity surfaced in the in vitro studies at concentrations up to 5000 μg of extract/plate (Ames test) or 5000 μg of extract/mL (chromosomal aberration test). No deaths or treatment-related toxicity were seen in the 6-month chronic oral toxicity study in Sprague-Dawley rats conducted at 3 doses (100, 300, and 1000 mg/kg body weight (bw)/d). The no observed effect level for CFE in this study was considered to be 1000 mg/kg bw/d. A prenatal developmental toxicity study conducted at 3 doses (250, 500, and 1000 mg/kg bw/d) in female Sprague-Dawley rats resulted in no treatment-related external, visceral, or skeletal fetal abnormalities, and no treatment-related maternal or pregnancy alterations were seen at and up to the maximum dose tested. CFE was not associated with any toxicity or adverse events.

Notochord to endoderm signaling is required for pancreas development

Development ◽  
1997 ◽  
Vol 124 (21) ◽  
pp. 4243-4252 ◽  
Author(s):  
S.K. Kim ◽  
M. Hebrok ◽  
D.A. Melton
Keyword(s):  
Gene Expression ◽  
Developmental Stage ◽  
Pancreas Development ◽  
Chick Embryos ◽  
Carboxypeptidase A ◽  
Bud Development ◽  
Dorsal Pancreas ◽  
Stepwise Manner

The role of the notochord in inducing and patterning adjacent neural and mesodermal tissues is well established. We provide evidence that the notochord is also required for one of the earliest known steps in the development of the pancreas, an endodermally derived organ. At a developmental stage in chick embryos when the notochord touches the endoderm, removal of notochord eliminates subsequent expression of several markers of dorsal pancreas bud development, including insulin, glucagon and carboxypeptidase A. Pancreatic gene expression can be initiated and maintained in prepancreatic chick endoderm grown in vitro with notochord. Non-pancreatic endoderm, however, does not express pancreatic genes when recombined with the same notochord. The results suggest that the notochord provides a permissive signal to endoderm to specify pancreatic fate in a stepwise manner.

The embryonic cerebellum contains topographic cues that guide developing inferior olivary axons

Development ◽  
1997 ◽  
Vol 124 (4) ◽  
pp. 861-870 ◽  
Author(s):  
A. Chedotal ◽  
E. Bloch-Gallego ◽  
C. Sotelo
Keyword(s):  
Inferior Olive ◽  
Positional Information ◽  
Original Position ◽  
Chick Embryos ◽  
In Vitro Experiments ◽  
In Vitro System ◽  
Target Region ◽  
Inferior Olivary ◽  
Anteroposterior Polarity

The formation of the olivocerebellar projection is supposed to be regulated by positional information shared between pre- and postsynaptic neurons. However, experimental evidence to support this hypothesis is missing. In the chick, caudal neurons in the inferior olive project to the anterior cerebellum and rostral ones to the posterior cerebellum. We here report in vitro experiments that strongly support the existence of anteroposterior polarity cues in the embryonic cerebellum. We developed an in vitro system that was easily accessible to experimental manipulations. Large hindbrain explants of E7.5-E8 chick embryos, containing the cerebellum and its attached brainstem, were plated and studied using axonal tracing methods. In these cultures, we have shown that the normal anteroposterior topography of the olivocerebellar projection was acquired, even when the cerebellar lamella was detached from the brainstem and placed again in its original position. We also found that, following various experimental rotations of the anteroposterior axis of the cerebellum, the rostromedian olivary neurons still project to the posterior vermis and the caudolateral neurons to the anterior vermis, that now have inverted locations. Thus, the rotation of the target region results in the rotation of the projection. In addition, we have shown that the formation of the projection map could be due to the inability of rostromedian inferior olivary axons to grow in the anterior cerebellum. All these experiments strongly indicate that olivocerebellar fibers recognize within their target region polarity cues that organize their anteroposterior topography, and we suggest that Purkinje cells might carry these cues.

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