Question

*MINIMUM 400 WORDS*

In the late 50’s and early 60’s children were born with deformities of the limbs to mothers that took the drug thalidomide for morning sickness. Address the following questions:

Why is an understanding of embryology important to identify the effect of potential teratogens on fetal development. Identify at least one other teratogen and what effect it has on fetal development. Discuss why thalidomide had a great effect on babies born in Europe, but the effect in the U.S was minimal.

Answer 1

Thalidomide was used to prescribed for the morning sickness and nausea to the pregnant women 60 years ago. But after some time its side effects were reported in the new born babies like limbs deformalities, any tissue/organ damage. These defects are said to be as thalidomide syndrome or thaliomide embryopathy.

It has been found that the thalidomide inhibits the angiogenic vascularization. During embryogenesis, vessels foemed first by vasculogenesis and are then modified into the complex vascular system that will be required for the fetal development and throughout out its life by the angiogenesis. thalidomide inhibits this process by causing its teratogenic damage by targetic embryo blood vessels.

the teratogenic ability of thaliomide also helps its to bypass an intrinsically important embryonic defense system that prevents the entry of the toxic substance from the entering embryonic cells and also escort the tagged toxicants out of the cell. These crucial function are performed by the efflux transporters found on the cell membrane. These are the members of the ATP-binding cassette protein family. Thaliomide is not recognized by the transporter proteins and therefore binding does not occur and chemical remains inside the cell.

To, understaand these mechanisms that why it is not recognized by transporters and how is it inhibiting the angiogenic vascularization in embryo, it is necessary to understand the embryology of the developing embryo.

Other teratogens are:

1. RUBELLA: it causes the miscarriage, preterm birth or still birth, congenital rubella syndrome or CRF

2. Aflatoxin b1: causes pregnancy loss, impaired placental growth, preterm birth, low birthweight.

In US Dr. Frances Kelsey of the US Food and Drug Administration was more alert and had not accept that the drug had been adequately tested for manufature and distribution. As a resuly only 20 children were born with disabilities in US. But in Europe the drug was containe in a prepration called Contergen, which was sold in all over the pharmecies that results into the birth of 6000 defected children out of which only 2000 were survived.