Methods of postnatal diagnostic.

Date: 2015-10-07; view: 399.

Prenatal methods of diagnostic.

X-ray examination is used to make diagnosis of anatomic defects (malformations). This method doesn't use at present time. The diagnosis of malformations realizes by ultrasonic examination. These methods are noninvasive.

The following methods are invasive methods. Among the methods of examination of embryo's tissues, tissues of chorion, amnion and placenta, and amnion liquid, the method of amnion liquid examination is used most often. The amnion liquid takes through the puncture of front abdominal wall and of front wall of womb (uterus). Then the liquid is examined by some methods, for instance by cytogenetical analysis and biochemical methods. The method gives possibility to diagnose chromosomal aberration and some disorders of metabolism.

Methods of citogenetic analysis.

Methods of cytogenetic analysis are methods to detect sizes, shape, and quantity of chromosomes.

Examination of sex chromosome number. To detect approximately the quantity of sexual X-chromosomes the express method may be used. The method is named “the method of X-sexual chromatin detection”. Healthy women have two X chromosomes, but active is one chromosome only. Other X chromosome is inactive (condensed). X-sexual chromatin is chromatin of condensed X chromosome (sexual heterochromatin or Barr body). This chromatin is visible by microscopying of tunica mucosa cells of mouth (tunica mucosa oris) or mucous tunic cells of vagina. Microscopying is realized after fixation and dyeing of material. Quantity of X chromosomes is calculated accordance the formula.

A = B + 1

A – quantity of X chromosomes, B – quantity of X-sexual chromatin bodies.

For instance, if quantity of X-sexual chromatin bodies is equal to 1 – the quantity of X chromosomes is equal to 2. If quantity of X-sexual chromatin bodies is equal of 2 – the quantity of X chromosomes is equal to 3. And so on.

There are some methods to detect the quantity of Y chromosomes.