Ganglionic eminence initially appears as a slight swelling in the floor of the cerebral
vesicle during the 5th fetal week and attains maximum prominence late in the 4 th fetal
month; it then declines in relative size, and nearly disappears after birth. The ganglionic
eminence constitutes a collection of the proliferating cells throughout most of span of
gestation and supply neuroblasts and spongioblasts to basal ganglia and pulvinar region
of thalamus and cerebral cortex.
Nowadays, intraventricular hemorrhage predominantly occurs in preterm infants of less
than 32 weeks gestational age, and the intraventricular hemorrhage arises most
frequently from rupture of a ganglionic eminence over the lower part of the head of the
caudate nucleus. It is also known that the ganglionic eminence hemorrhage is equally
frequent in both hemispheres and is associated with an extensive destruction of the
capillary bed without arterial or venous rupture. Although fibrin thrombi are seen within
veins in relation to ruptures at the capillary vein junction, the other study reveals little
or no fibrin is to be seen within the ganglionic eminence hemorrhage presumably due to
the high fibrinolytic activity within this region of the immature brain.
Accordingly this study was planned to evaluate the ganglionic eminence of fetal brain
in two aspects, i.e. , morphological development of ganglionic eminence during gestation
and functional maturation by measuring fibrinolytic activity of various portions of
developing brains.
To evaluate the development of ganglionic eminence a total of 97 brains of Korean
fetuses of gestational ages ranging from 16 to 37 weeks, was studied; 62 for
morphological study , find 35 for functional study.
The fetuses were products of therapeutic abortions, and were proved to be normal
after complete examination of fetuses and placentas. The brains were removed as soon
as possible after delivery, and were fixed in 10% formalin for 1 to 2 weeks before being
examined. Representative blocks containing white matter around lateral ventricle,
gangtionic eminence, caudate nucleus and thalamus on the serial coronal sections.
Through routine histological procedure, slides were made and stained with hematoxylin
and eosin for microscopical examination of the ganglionic eminence and striatum.
The fibrionlytic activity of the tissue was measured by fibrin plate method of Astrup
and Alb. rechtsen and the amount of lysis expressed as area/㎎ of wet tissue. As
controls comparable aliquots of 2M potassium thiocyanate or saline alone had no
fibrinolytic activity. To detect the in vivo fibrinolysis, fibrin and/or fibrinogen
degradation product, staphylococcal clumping tests for the tissue extracts were
performed.
Following results were obtained.
1) The ganglionic eminence was well formed and located at the lateral side of
terminal vein and over the caudate nucleus and protruded into the lateral ventricle.
2) The thickness of the ganglionic eminence is reached to maximum width by 20 th
week of gestation and is shown a progressive reduction still 30 th week, and revealed
sharp reduction after 31th week of gestation and became no longer recognizable after 37
th week of gestation.
3) The ependymal farer was most thickened at 16∼19 th week of gestation, showing
6∼8 layers with numerous mitoses and declined to 2∼3 layers at 28∼31 th week of
gestation and no more mitosis was found.
4) The distribution of capillary beds were most pronounced at 16∼19th week of
gestation and the permeation of the capillaries to the epegdymal zone and decreased in
number after 20 th week of gestation. The medium sized, well developed veins were
demonstrable at the junction of ganglionic eminence and caudate nucleus from 24 th
week of gestation.
5) The fibrinolytic activity of the choroid plexus and leptomeninges were significantly
increased than the other areas(p<0.005) and there was no evidence of gestational
changes.
6) The fibrinolytic activity of the ganglionic eminence was no more pronounced than
those of cerebral cortex, periventricular white matter, cerebellum and spinal cord.
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