Small Scale extraction of DNA from blood and its utility in forensic work

Forensic scientists are constantly searching for biological characteristics that are so variable among individuals that an observed match found in material left at the scene of the crime could be taken as conclusive proof linking a suspect with the crime. Fingerprints are the most famous and widely used example. However, the circumstances under which fingerprints are left and recovered in good condition are limited, so recourse is been made to other physical remains of a crime, like blood type or other body fluids. These properties, far from being unique, only narrow down the identification to a group, and sometimes a very large group. With the growth of DNA technology has come convincing evidence that each individual's DNA sequence is unique. Turning this theoretical principle into a reliable practical tool is the goal of forensic scientists. So far, the approach has been to find short stretches of DNA that differ from one individual to the next in ways that can be determined rapidly with high reliability and minimal cost due to our meagre resources. DNA studies nas not yet been used in Pakistan in the field of Forensic, where as it is vastly used in other developed countries

Confirming suspected pesticides poisoning and monitoring the efficacy of treatment by measuring the plasma enzyme activity

The inhibitors of plasma cholinesterase include many diverse biologically active substances, the inhibitors which most frequently cause toxicological problems are the nerve gases and the systemic insecticides [parathion and malathion]. Most of these substances inhibit both acetylcholinesterase and plasma cholinesterase, in general the plasma enzyme is more susceptible to inhibition than the red cell enzyme, in consequence plasma cholinesterase activity has been used as a biochemical indicator for the presence of some types of inhibitors and to assess subsequent recovery. Measurement of plasma cholinesterase activity and determination of phenotypes by using fluoride and dibucaine as inhibitors has also shown to be a sensitive method for monitoring and controlling exposure to organophosphate [OP] compounds in medicolegal cases. The Organophosphate compounds are covalently bounded to the catalytic active site of cholinesterase enzyme which produces irreversible inhibition, a normal plasma cholinesterase activity excludes systemic poisoning by organophosphate. The classical method for phenotyping requires a good resolution of spectrophotometer to monitor at 240nm wave length, the rare of hydrolysis of benzolycholine by plasma cholinesterase in phosphate buffer pH 7.4 at 26°C, is observed and recorded on printer

Estimation of plasma cholinesterase enzyme activity and phenotypes in Pakistani population

The use of plasma cholinesterase for forensic purpose is no different from the use of other enzymes that are genetically variable. There are two advantages, first of all, it is very stable and it deteriorates slowly so that old malodorous blood samples can be used for phenotyping and also scrapings of dried blood stains, when redesolved in buffer, can be used. The second advantage is that the heterozygote E1uE1a can easily be recognised so that pedigree determinations are usually clear. The frequency of different genes varies with different ethnic populations. The real understanding of the genetics of plasma cholinesterase variations is essential for interpretation of data for forensic purposes. The classical method requires a spectrophotometer to monitor at 240nm wave length. As data from many countries were taken, Pakistani data was not available, so this data will enable us in the genetic determination, for treatment of Organophosphorous poisoning cases, and in case of Suxamethonium sensitive individuals