Task 1. Situational tasks:
A 4-day-old newborn was delivered to the clinic. From the history of the disease it is known: a child from a second pregnancy, full-term, birth weight is 3500g. Pregnancy proceeded normally, childbirth was normal. The child cried immediately. After trying to give the child a drink of sweet water a cough, cyanosis and vomiting appeared. During feeding expressed breast milk from a spoon, vomiting, cyanosis also appeared immediately, and foam flowed through the nose. Vomit is without signs of caseation. On the third day, the doctor suspected a child with a malformation - atresia of the esophagus.
Questions for discussion:
1. What are the mechanisms of this embryopathy?
2. What types of apoptosis and their distinctive features do you know?
3. What type of apoptosis occurs with atresia? Explain.
1. mechanisms of this embryopathy
The fundamental morphogenetic process appears to be a rearrangement of the proximal foregut into separate respiratory (ventral) and gastrointestinal (dorsal) tubes. This process depends on the precise temporal and spatial pattern of expression of a number of foregut patterning genes. Disturbance of this pattern disrupts foregut separation and underlies the development of tracheo-oesophageal malformations.
2.types of apoptosis and their distinctive features
The two major types of apoptosis pathways are “intrinsic pathways,” where a cell receives a signal to destroy itself from one of its own genes or proteins due to detection of DNA damage;and “extrinsic pathways,” where a cell receives a signal to start apoptosis from other cells in the organism. The extrinsic pathway may be triggered when the organism recognizes that a cell has outlived its usefulness or is no longer a good investment for the organism to support.
3.type of apoptosis that occurs with atresia
Granulosa cell apoptosis is promoted by tumor necrosis factor-alpha (TNFα), though the mechanism of TNFα is unclear.
tumor necrosis factor alpha (TNF alpha) and receptors
Fas ligand and receptors
TNF-related apoptosis-inducing ligand (TRAIL; also called APO-2) and receptors
APO-3 ligand and receptors
PFG-5 ligand and receptors
TNF-related apoptosis-inducing ligand TRAIL activates Caspase 3 (CASP3), which in turn interacts with caspases 6, 7, 8, 9, and 10 to induce apoptosis in granulosa cells.