Example Of Essay On Medicine

Cardiovascular Quiz

Q1. What is the advantage of SELDI-TOF-MS based assays over conventional methods?
Surface-enhanced laser desorption/ionization time of flight (SELDI-TOF) mass spectrometry (MS) is advantageous over conventional methods as it can use endogenous synthetic substrates. Moreover, it has the ability to directly determine enzymatic peptide products. It is also a rapid, reproducible and sensitive method for the analysis of enzymatic activities of renin–angiotensin system (RAS).

Q2. What is the difference between carboxy peptidases and endopeptidases?

Carboxypeptidases are exopeptidases that are used to cleave (hydrolyze) amino acid residues from the carboxy-terminal (C-terminal) portion of proteins, whereas endopeptidases cleave amino acids from the nonterminal portion of proteins.

Q3. What are the biological activities of Ang (1-9) and Ang (1-7)?

Ang I cleavage results in the formation of Ang (1-9) and Ang (1-7). Ang (1-9) is a strong competitive inhibitor of ACE. It is also found to have vasoconstrictive activity. On the other hand, Ang (1-7) is a strong vasodilator peptide. Both Ang (1-9) and Ang (1-7) enhance bradykinin activity on the B2 receptor by increasing arachidonic acid as well as nitric oxide release.

Q4. What is the effect of diabetes on ACE and ACE2 activity and expression?

Plasma ACE1 activity increases in diabetes. ACE2 expression is also increased in diabetes at the posttranscriptional level.

Q5. What effect does captopril and lisinopril has on ACE2 activity?

Lisinopril and captopril, which are actually ACE1 inhibitors, have no affect on ACE2 activity, i.e. ACE2 is not inhibited by lisinopril or captopril as these drugs are unable to bind to ACE2.

Q6. What is the effect of deleting AT1R on blood pressure? Why?

Angiotensin II type I receptor (AT1R) is directly involved in the cardiovascular system. It has two forms, AT1a and AT1b. Specifically, Ang AT1a receptors are important in the control of blood pressure. Absence of Ang AT1a receptors can result in chronic hypotension as well as significant increase in renin mRNA. This receptor along with Ang II produces vasoconstriction that is helpful in increasing blood pressure, but the absence AT1R results in the absence of vasoconstriction resulting in decreased blood pressure.

Q7. What is the effect of EDTA on ACE and Renin activity?

ACE1 activity is blocked as a result of chelating agents such as EDTA. On the other hand, renin activity is not affected by chelating agent such as phenanthrolene and probably EDTA.
Q8. Briefly describe the RAS pathway.
Renin–angiotensin system (RAS) pathway starts with the conversion of angiotensinogen (AGT) to angiotensin I (Ang I) through renin that is followed by the action of angiotensin-converting enzyme (ACE). This enzyme catalyzes the cleavage of the C-terminal dipeptide from the inactive decapeptide, Ang I, to generate the strong vasoconstrictor, angiotensin II (Ang II). Ang II is the most important mediator of RAS. It attaches to two different types of receptors known as Ang II type 1 (AT1) and Ang II type 2 (AT2) receptors. AT1 is involved in most of the important physiological actions of Ang II in cardiovascular, renal, and neuronal systems. AT2 is found to be involved in cell growth and vasodilation.

Q9. What did you find most difficult or interesting regarding the assignments?

Most interesting part of the assignment was the study of SELDI-TOF-MS, which is an analytical technique to directly check and determine enzyme peptide products without any ambiguity, i.e. it is helpful in the study of protein mixtures. This technique can also be considered a slightly difficult task in the research.