| Objective FISH was performed with specific probes to make the rapid prenatal diagnosis of the fetal sex chromosome on uncultured amniotic fluid in order to know its accuracy, as well as to obtain the advantages and disadvantages of the domestic probe and it's effectiveness, or find suitable experimental conditions.Methods We obtain the amniotic fluid specimens through amniocentesis, select 15 pregnant women between 18-23 weeks gestational age from November 2007 to June 2008 at the Third People's Hospital of Hefei. FISH was performed respectively with domestic centromeric probe (CSP)X/Y on the uncultured amniotic fluid samples,and the cultured samples were analyzed by cytogenetics to find the concordance rate between FISH and standard cytogenetics. In the experimental process, we improve experimental conditions to obtain the desired resultsResults 14 samples can produce hybridization signals well.1 sample hybridization signals is not well, and the results were obtained in 48 hours.Hybridization success rate was (14/15)93.3%.Eight cases of male births and six cases of female births.The amount of sex chromosome in all specimens is normal. 15 samples were successfully cultured and analysized karyotype. Nine cases of male births and six cases of female births. 100% concordance was observed. The main advantage of domestic probes is rapid, accurate, easy to operate and have the price advantage, the main disadvantage of probe is that fluorescent signals are unstable and easily quenched. We carried out a series of adjustments: in accordance with the amniotic fluid sediment content, increase the amount of the collagenase B from 5ml to 7ml; adjust pepsin time from 10 minutes to 12 minutes; increase probe denaturation temperature from 73℃to 78℃; extend hypotonic time from 20 minutes to 30 minutes and so on. The experimental results can be satisfactory.Conclusions (1)There was 100% concordnce rate in two methods.FISH is rapid,accurate,and easy to opperate.(2)The probes of domestic manufacture used for experiment have the advantage of price,and can also get satisfactory results at the same time. The disadvantage of the probes is that the fluorescent signals are unstable and easily quenched. To improve the experimental conditions, it can be aquired the same results with similar products. |
