Introduction:Cellular Pathology in recent years hasbecome more closely involved in the direct management of patients with theintroduction of molecular technologies and targeted therapies. Through this, wehave seen the introduction of specialist pathology. These concepts and the keytechnologies that are influencing clinical practice today have been introduced.
It showed that how clinical practice has been affected by these respectivetechnologies and how further development will influence the practice anddelivery of cellular pathology, which will impact on the patient throughtargeted therapeutics and diagnostics. Discussion:There are many types of advanced techniquesin cellular pathology.DNAprofiling:Principle:3,000,000 base pairs of nucleotide thatis 0.1% of the genomes are unique in all human being. This speciality in the basesequences occur in repetitive DNA also known as satellite DNA as well as ingenes. Various small peaks are formed on the DNA which gives rise topolymorphism due to density gradient configuration in the satellite DNA. Variable number tandem repeats (VNTR)is one of the main satellite DNA having high degree of polymorphism.
Since achild receive 50% of the DNA from its father and the other 50% from his mother,so the number VNTRs at a particular area of the DNA of the child will bedifferent may be due to insertion, deletion or mutation in the base pairs. As aresult, every individual has a distinct composition of VNTRs and this is themain principle of DNA fingerprinting.Application:DNAprofiling, as already indicated, has application in a broad cross section ofdisciplines, including human forensic science, diagnostic medicine, familyrelationship analysis, animal and plant sciences, and wildlife forensicscience. DNA profiling is applicable in a number of areas in medicine including twin zygosity testing , bone marrowtransplantation marker analysis, detection of DNA changes in tumors, indicationof possible contamination of fetal by maternal tissue in chorionic villusanalysis, pathogen identification and paternitytesting where family studies are being performed for antenatal diagnosis ofinherited diseases.Polymerase chainreaction (PCR):Principle:The principle of PCR involves the primer mediated enzymatic amplificationof DNA. The ability of DNA polymerase to synthesize new strand of DNAcomplementary to the offered template strand are by using PCR. DNA polymerasecan add a nucleotide only onto a preexisting 3?-OH group to add the firstnucleotide, so the primer is needed.
DNA polymerase then elongated its 3 end byadding more nucleotides to generate an extended region of double stranded DNA.Applications:There are many applications of PCRincluding to test the presence of genetic disease mutation such as cysticfibrosis, hemoglobinopathies or other inborn errors of metabolism. It can usedto study the alteration to oncogene that causes cancer. It is also a tool usedin genetic fingerprinting. In a crime investigation, there may only be tiny DNAsample to work with to identify anyone from the million.
Real-time PCR (RT-PCR):Principle:Real-time PCR is the continuouscollection of fluorescent signal from one or more polymerase chain reactionsover a range of cycles. PCRproducts is enabled by the inclusion of a fluorescent reporter molecule in eachreaction well that yields increased fluorescence with an increasing amount ofproduct DNA by real-time detection. The fluorescencechemistriesemployed for this purpose include DNA-binding dyes and fluorescently labeledsequence-specific primers or probes. The fluorescence signal as amplificationoccurs are monitor by using specialized thermal cyclers equipped withfluorescence detection modules. The measured fluorescence is proportional tothe total amount of amplicon; the change in fluorescence over time is used tocalculate the amount of amplicon produced in each cycle.
RT-PCRassays have become the best of choice for the rapid and sensitive determinationand quantitation of nucleic acid in various biological samples, with diverseapplications such as gene expression analysis, the detection of geneticallymodified organisms in food, and cancer phenotyping. Applications:Thetool of choice for the rapid and sensitive determination and quantitation ofnucleic acid in various biological samples is real-time PCR assays. The detectionof genetically modified organisms in food, gene expression analysis and cancerphenotyping are main applications of real-time PCR. In research laboratories,RT-PCR assays are widely used for the quantitative measurement of gene copynumber (gene dosage) in transformed cell lines or the presence of mutant genes.It can be used to precisely quantitate changes in gene expression, for example,an increase or decrease in expression in response to different environmentalconditions or drug treatment, by measuring changes in cellular mRNA levels.