A new technique for foetal brain fixation and extraction

Abstract

We performed a new technique for foetal brain fixation and extraction that offers a remarkable reduction in sampling time facilitates specimen handling while conserving high quality. With the new fixation method, it is possible to obtain samples adequate for macroscopic and microscopic observations and immunohistochemical analysis. The technique involves the creation of an ex vacuo phenomenon in the subarachnoideal space prior to injecting the fixative solution. In this manner, the solution is homogenously distributed. Ease, reproducibility and the possibility of standardizing the procedure are the principal advantages. Low costs, reduced wording time and less need for human resources are other advantages. Histologically, we obtained, quickly, high quality slides with routine and immunohistochemical stains. Disadvantages of the technique derive from the use of formaldehyde and glacial acetic acid, rather than water to wash the samples; thus one must work in a well ventilated area, with gloves, protective glasses and an adequate lab coat to avoid skin and respiratory tract damage.

Cystic dilation of the ventriculus terminalis in adults

“…In contrast, we performed fetal spinal cord fixation using a particular fixative solution (30% formaldehyde, 30% glacial acetic acid, and 40% distilled water) to facilitate specimen handling and extraction and to obtain adequate samples for macroscopic and microscopic observations and immunohistochemical/ultrastructural analysis. 5 After the fetal spinal cord extraction, sequential transverse biopsy specimens from the dorsal region and conus medullaris of the spinal cord were obtained, sampled, and embedded in paraffin blocks sectioned at a thickness of 4 mm and stained with H & E. Finally, only 2 paraffin blocks of each of the 5 fetuses with a central canal of the dorsal spinal cord and VT were selected for immunohistochemistry and ultrastructural analysis.…”

“…Ultrathin sections were cut on an LKB Ultratome, contrast-stained with uranyl acetate and lead-citrate, and examined under a Philips CM-10 electron microscope. 5 The obtained results were compared with those of the VT as reported in Case 2, with the understanding that variations exist among ependyma of fetuses and adults.…”

From fix to fit into the autoptic human brains

“…18 , 19 Currently, the formalin, alcohol and acetic acid mixed protocol is utilized for foetal brain fixation. 20 , 21 We decided to modify and utilize the foetal protocol for perinatal and postnatal brains, dividing the time of fixation in steps of four days for each passage ( Table 1 ). We adapted protocols for adult brain fixation according to this postnatal protocol, to unify all of protocols in time point of multiple of four days.…”

Fixation and staining methods for macroscopical investigation of the brain

“…The brain can be removed up to 5 days after the fixation and should be then placed in Zamboni solution ( Bass et al, 1993 ). Cimmino et al (2002) use a solution made up of 3 parts of anhydrous acetic acid, 3 parts of 40% formaldehyde and 4 parts of distilled water. The fixative should be injected through the anterior, posterior, and mastoid fontanelles.…”

“…The fixative should be injected through the anterior, posterior, and mastoid fontanelles. After placing the fetus for 20 h in formalin, it is possible to extract the brain for macro- and microscopic examinations ( Cimmino et al, 2002 ). In the attempt to perform a neuropathological examination in short times, so that the funeral must not be overly delayed, a heat accelerated fixation protocol was established for pediatric brains.…”