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MORPHOMETRIC INDICATIONS OF MYOCARDIAL STRUCTURES OF
COMMON AMNIOTIC TWINS WITH COMMON COMMON AMNIOTIC
TWINS PREPARED AT DIFFERENT PERIODS
Jumanov Z.E.
Urunova M.A.
Samarkand State Medical University, Samarkand Sh., Uzbekistan
https://doi.org/10.5281/zenodo.15601812
The purpose of the study:
Determination of morphometric indicators of
myocardial structures of monoamniotic twins with common placenta born at
different periods.
Materials and methods of the study:
Morphological and morphometric
aspects of myocardial structures of 178 twins who died from atelectatic
pneumopathy in the multidisciplinary clinic of Samarkand State Medical
University were studied. In this case , tissue fragments measuring 1x1x0.5 cm
were taken from the left ventricle and interventricular septum of the heart from
the section materials obtained during autopsy for special histological
examination. The obtained tissue fragments were fixed in 10% neutral formalin,
passed through an alcohol battery, and paraffin blocks were prepared. The
prepared histological sections were stained with hematoxylin and eosin, Van
Gieson, and Weigert methods. Histological preparations were used to study the
myocardial layer, cardiomyocytes, intermuscular spaces, intramural blood
vessels of various calibers, rheological properties of blood within the vessel, and
the perivascular space (PVS). Morphometric examination was performed to
objectively assess the structure of the muscle and blood vessels. For this, a dot
grid of 4 small squares (consisting of 100 points) recommended by G.G.
Avtandilov was used. Morphometric measurements were performed at the size
of the microscope ob.20xok.10. In this case, the number of points falling on
cardiomyocytes and sclerotic tissue, as well as the number of PVS and blood
vessels located in it, was counted. Also, to study the morphometric aspects of the
structure of cardiomyocytes, sclerotic tissue, and blood vessels, an ocular
micrometer recommended by G.G. Avtandilov was used.
Results of the study.
In monoamniotic twins with a common placenta
who were born and died at different terms, the pathomorphological parameters
of the hearts of twins with a small heart volume differed from those of twins
with a large heart volume by birth dates. In this case, specific differences were
detected in the interventricular edema, the proportion of the blood vessel space
and wall, the perivascular space, and the diameter of cardiomyocytes. In
monoamniotic twins with a large heart volume who were born and died at
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different terms before 28 weeks of gestation, the area occupied by muscle tissue
in the myocardial layer was 66.1±0.90 , and the area occupied by
interventricular edema was 19.1±0.36 . In twins born at 28-32 weeks, these
indicators are 73.1±0.68 and 25.4±0.43 , respectively . In those born at 32-37
weeks, the morphometric indicators of the area occupied by muscle ( 76.4 ±0.36
) and fibrous tissue ( 28.6±0.46 ) are equal. In monoamniotic twins with a
common placenta, with a relatively small heart volume, these indicators are in
the ratio of 64.7±0.79/ 18.4±0.37; 70.3±0.98/ 24.3±0.66; 74.5±0.73/ 27.8±0.33.
In twins with almost identical heart volumes, these indicators are
65.0±0.88/18.6±0.44;
71.0±1.02/24.07±0.60;
74.9±0.69/28.1±0.25,
respectively.
Morphological changes in cardiomyocytes of monoamniotic twins with
large and small heart volumes and close heart volume parameters have specific
morphometric parameters depending on the timing of birth and heart volume.
In diamniotic twins with a common placenta and a relatively large heart
volume, born and dying before 28 weeks of gestation, the morphometric
parameters of cardiomyocytes were 2.2±0.04 μm, while these parameters were
2.58±0.06 μm in twins born at 28-32 weeks of gestation. At 32-37 weeks of
gestation, they were 2.93±0.03 μm, respectively. In the group with a relatively
small heart volume, these parameters were 2.11±0.03; 2.45±0.08; 2.74±0.11 μm.
In the latter group, these parameters were 2.14±0.03; 2.48±0.07; 2.89±0.08 μm.
In monoamniotic twins with a common placenta born and dying before 28
weeks of gestation, the area occupied by the intramyocardial blood vessel wall is
34.0%, and the area occupied by the blood vessel space is 66.0%, while in twins
at 28-32 weeks of gestation, these indicators are 39/61%, respectively. In twins
at 32-37 weeks of gestation, the area occupied by the blood vessel wall is 38%,
and the area occupied by the blood vessel space is 62%. In twins with a
relatively small heart volume, these indicators are 40/60% (before 28 weeks);
36/64% (before 28-32 weeks); 41/59% (up to 32-37 weeks), 39/61% up to 28
weeks in identical twin fetuses with the same heart rate; 37/63% up to 28-32
weeks; 41/59% in twin fetuses born and dying up to 32-37 weeks.
In monoamniotic twins with a large and small heart volume and similar
heart volume parameters, the ratio of the areas occupied by blood vessels and
perivascular space varies depending on the term of birth and heart volume. In
monoamniotic twins with a large heart volume who were born and died before
28 weeks of gestation, the area occupied by intramyocardial blood vessels was
76%, while the area occupied by PVB was 24%. In twin fetuses born and died
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before 28-32 weeks of gestation, the blood vessels occupied 70%, and PVB
occupied 30% of the area. At 32-37 weeks, it is noted that the blood vessels
occupied 71% of the area, and PVB occupied 29%. In monoamniotic twins with a
common placenta, which have small heart volumes and are relatively close to
each other, the ratio of /76/24; 72/28; 71/29 and 75/25; 73/27; 60/40 is
observed, depending on the date of birth.
Conclusion.
Thus, in monoamniotic twins with a common satellite, born
before 28 weeks of gestation and living and dying at different times, the area
occupied by muscle tissue in the myocardial layer is a greater percentage than in
twins born between 28 and 32 weeks of gestation, and with increasing
gestational age, the proportion of intermuscular area is observed to increase.
In the myocardial layer of a heart with a larger size, cardiomyocytes have
higher indices, but the morphometric indices of cardiomyocytes of twin fetuses
with almost equal volumes are similar to those of a heart with a larger and
smaller volume.
The indices of the area occupied by the blood vessel wall and the blood
vessel space of intramyocardial blood vessels of different sizes born and living at
different terms do not have significant differences depending on the dates of
birth. However, depending on the size of the heart and the dates of birth,
differences are noticeable in the indices of the area occupied by the blood vessel
wall and the space. This phenomenon can be expressed, firstly, in relation to the
size of the heart and the date of birth, and secondly, due to pathomorphological
changes in the blood vessel wall.
The proportions of the area occupied by intramyocardial blood vessels and
PVB in monoamniotic twin fetuses with common placenta born and living at
different terms differ depending on the size of the heart. In particular, in twins
with a larger heart size, the area occupied by PVB is greater. Also, as the birth
period increases, the indicators of the area occupied by blood vessels and PVB
also increase
