Hemoglobin-oxygen dissociation curve. The hemoglobin tetramer can bind up to four molecules of oxygen in the iron-containing sites of the heme
molecules. As oxygen is bound, 2,3-BPG and CO2 are expelled. Salt bridges are broken, and each of the globin molecules changes its conformation to facilitate oxygen binding. Oxygen release to the tissues is the reverse process, salt bridges being formed and 2,3-BPG and CO2 bound. Deoxyhemoglobin does not bind oxygen efficiently until the cell returns to conditions of higher pH, the most important modulator of O2 affinity (Bohr effect).
Populations in Southeast AsiaandSouthChinahave highfrequencies ofa-thalassemia
caused by a-globin gene mutations and/or deletions. This study was designed to find
an efficient and simple diagnostic test for the mutations and deletions. A duplex polymerase
chain reaction (PCR)/denaturing high-pressure liquid chromatography
(DHPLC) was used to detect the mutations and deletions. A blinded study of 110
samples, which included 92 a-thalassemia samples with various genotypes and 18
normal DNA samples, was carried out by the methods.
There are many textbooks to chose from when preparing for the FRCA
examination; the candidate suffers not from lack of information but rather
from being inundated with it. The candidate then has the task of information
sorting and data compression to memorize and utilize all this information.
Graphic representation of data is an excellent form of data compression; figures
or drawings are frequently asked about at the viva examination, particularly
since the candidate’s understanding of a problem comes across most
clearly when drawing a figure or a using a picture.