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Placenta Throughout Gestation
Published in Mary C. Peavey, Sarah K. Dotters-Katz, Ultrasound of Mouse Fetal Development and Human Correlates, 2021
Mary C. Peavey, Sarah K. Dotters-Katz
The mouse placenta is comprised of trophoblast cells and blood vessels; as in humans, the trophoblast cells develop from the outer layer of the embryo (trophectoderm). In mice, the chorioallantoic attachment occurs at 8.5 dpc, followed by the development and growth of the vascular network. This is the site of maternal fetal exchange that is equivalent to the human placenta villi (2,10). At 9.5 dpc, the chorio-allontoic fusion is completed, allowing for placental formation, and remodeling of the umbilical vessels to form the vein and artery. The mouse placenta gains full function capacity at around 10.5 dpc; at this time it is composed of three areas – the maternal decidua, the junctional zone and the labyrinth (11). The placenta has two vascular systems, maternal and fetal, and the appropriate perfusion is essential for exchanging of functions between them.
Alternative Methods for Assessing the Effects of Chemicals in the Eye
Published in David W. Hobson, Dermal and Ocular Toxicology, 2020
Leon H. Bruner, John Shadduck, Diane Essex-Sorlie
Selected technique — Chorioallantoic Membrane (CAM).87,96 The CAM assays have generated considerable interest as alternatives for ocular irritation testing. The CAM is the vascularized respiratory membrane found immediately beneath the shell of a developing bird inside an incubated egg. Initially it was thought the CAM was analogous to the conjunctiva and therefore a good conjunctival inflammation model. However, additional studies have shown that classical inflammatory responses are not observed after treatment of the CAM91,97 and the primary lesions assessed after treatment with test substance are observations of necrosis or vascular changes. Thus, these assays should more properly be considered morphology endpoint procedures.
The Transfer of Passive and Active Immunity
Published in Gérard Chaouat, The Immunology of the Fetus, 2020
C. H. F. Nevard, M. Gaunt, C.D. Ockleford
However, in any species, at least one of the following — chorioallantoic placenta, yolk sac placenta, mammary gland, and preclosure small intestine — must effect a concentration and selection process such that enriched antibody is available to the neonate within a short time of birth (Figure 4). At the cellular level, it is emerging that the concentration process is dependent on receptor-mediated endocytosis via coated vesicles at an epithelial surface in at least one of the organs listed.35,79-81
Phase Transition Microemulsion of Brimonidine Tartrate for Glaucoma Therapy: Preparation, Characterization and Pharmacodynamic Study
Published in Current Eye Research, 2021
Nivedita Gautam, Karthikeyan Kesavan
Estimation of irritancy levels of the developed PMEs is done by HET-CAM test.20 Briefly, fertilized chicken eggs weighing 40–50 grams were collected from commercial sources and candled to remove the nonviable or defective ones. The eggs were incubated at 37 ± 0.5°C and 40 ± 5% humidity for 9 days. The eggs were rotated 180° manually in a gentle manner thrice a day to ensure proper development and embryo viability. The eggs were placed at equatorial position so that chorioallantoic membrane should develop away from the egg shell. On 9th day, the eggs were candled to confirm fertility and identify the airspace, marking was done. After complete incubation of 10 days, egg shell of each egg of three groups was opened at that marked portion. The inner membrane is cautiously removed with the help of forceps without disrupting the blood vessels to expose the chorioallantoic membrane underneath. The 300 µl volume of 0.9% saline solution (negative control), 0.1 M NaOH (positive control) and test solution (PMEs) was added onto the CAM by a pipette directly, and a timer started. Any effects like hemorrhage, lysis, and coagulation were assessed. After the treatment, semi-quantitatively grade using the method developed by Gupta et al. (2010)21 was performed. Each test solution is allotted a grade on the basis of haemorrhaging visibility. Images were taken to record qualitative data. The scores were recorded as per the scoring schemes.
Retinal teratogenicity of pregabalin in chick embryo model
Published in Cutaneous and Ocular Toxicology, 2020
The values of the incubator were adjusted one day before the experiment to 37 °C (±0.2 °C) and 50% (±5) humidity with a rotation of 45 degrees every 6 h. On the day of the experiment, all eggs were cleaned with ethanol. Using a needle, a 0.5 mm hole was created on the blunt end of the eggs (to the top of the air sac)29. The pre-determined doses (drug and solvent) were applied to the air sacs of each egg using a 26 G needle. The holes were closed using a sterile band and the eggs were placed in an incubator with the blunt end in the upright position. The eggs were checked twice a day for temperature and humidity. The day the eggs were placed in the incubator was denoted as “day 0.” On day 10, all eggs were opened. The chorioallantoic membranes, blood vessels, yolk sac, and egg whites of the fertilised eggs were carefully removed and the embryos were harvested. Embryos were rinsed several times with physiological saline solution and placed into 10% neutral-buffered formalin solution.
Preparation of levofloxacin loaded in situ gel for sustained ocular delivery: in vitro and ex vivo evaluations
Published in Drug Development and Industrial Pharmacy, 2020
Pooja Jain, Chandra Prakash Jaiswal, Mohd. Aamir Mirza, Md. Khalid Anwer, Zeenat Iqbal
For irritation assessment, HET-CAM assay method was selected. For this, three fertile eggs (45–65 g) were selected on non-defective basis. These eggs were then incubated (10 days) at incubator conditions of 37 ± 2 °C temperature and 55 ± 7% RH. The eggs were scratched off and pared off carefully at the end of 10th days. Further, chorioallantoic membrane of the eggs was exposed by removing inner membrane carefully. After this, 0.5 ml of formulation was instilled through window directly and kept contact for 5 min. The vascular damage of the membrane was examined and injury time was noted down, scores were recorded. Normal saline and 0.1 M sodium hydroxide solutions were used as positive and negative controls, respectively. The probability of irritation of the formulations was studied for hyperemia, hemorrhage, and coagulation [24].