الفهرس 
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Abstract
The present study was concerned with testing the
effect of hypercalcaemia on the cell kinetics and
chromosomal structure. The blood leukocytes - grown
in vitro - were utilized as an experimental model in
this respect. The blood samples were obtained from
two groups of donors, namely; a male group comprising
8 donors and a female group comprising 7 ones. The
leukocytes were separated and the initial cell density
was adjusted to fit 200 x 103 lymphocytes per millilitre
of culture medium utilizing the cetrimidepronase
technique. The lymphocytes were enhanced to
undergo proliferation either by the plant lectin
phytohaemagglutinin (PHA) or by mixing the bloods of
two separate donors (histocompatibility antigenic
activation). The calcium ion level was adjusted to
fit the ascending tested concentrations through
titrating the tested solution against 1/50 N EDTAbuffered
solution and the end point was the change of
colour from purple to blue.
In experiment I, the leukocyte suspension of each
donor was divided -into 21 aliquots, one representing a
control standard culture and five experimental
quadruplets. The calcium ion level was adjusted to 50
j.lg/ml. in the control culture and to 70, 90, 110, 130
and 150 )lg/ml. in the first, second, third, fourth and
fifth quadruplets respectively. Four experimental
models were employed in each group of quadruplets
depending on the time of advent of calcium ion into
the culture, namely; simultaneous addition of calcium
ion and the mitogen (model A) and five minu tes, one
hour and six hours after the addition of the mitogen
(models B, C and D respectively). In experiment II ,
five culture series were prepared from 10 donors and
the same models were utilized according to the time
lapse between blood mixing and the adjustment of
artificial hypercalcaemia.
The index of the proliferative response was estimated
by the cell density of the cultures; quantitated at
24, 48, 72 and 96 hours from the inoculation time
(Time 0). After 96 hours of incubation, the smears
were prepared from each culture tube and were used to
estimate the transformation score as well as the
chromosomal structure. In chromosomal study, 10
slides were chosen at random - for each culture tube -
and 50 metaphases (Exper iment I) or 100 metaphases
(Experiment II) were examined under the oil-immersion
objective, photographed and karyotyped according to
the standard human chromosome nomenclature.
The results of the present investigation revealed the
following:-
1- In control cultures, the proliferative response was
significantly higher in the female donors than in
the male ones.
2- Elevation of the calcium ion concentration to 70
)-Ig/ml. (equivalent to 14 mg% in the blood) resulted
in an increased response in the male cultures
whereas the female proliferative response was
suppressed.
The suppressive effect of the 90
concentration (equivalent to blood level of
was more evidenced in the female cultures
)-Ig/ml.
18 mg%)
than in
those of the male group.
4- Higher calcium ion concentrations (110 and 130
)-Ig/m~.) which are equivalent to blood levels of 22
and 26 mg% were irreversibly toxic to the cells of
both groups of donors although the latter
concentration was nearly completely lethal to the
female cultures.
5- Still higher calcium ion concentration (150~g/ml.)
which is equivalent to a blood level of 30 mg% was
completely lethal to both groups of cultures as
shortly as 24 hours of incubation.
6- The maximum yield of abnormal karyotypes was
recorded with the 90 ~g/ml. concentration in both
groups of donors in all experimental models. The
prevailing anomalies met with in this concentration
were tetraploidy and endoreduplication.
7- Chromosomal breaks, however, were highly frequent
with higher calcium ion concentrations (110 and 130
yg/ml. ).
In conclusion, the data obtained by the present
investigation may provide an evidence that the female
immunocompetent cells are more susceptible to the
drastic effect of high calcium ion concentrations. In
addition, chromosomal abnormalities are much more
expected in the females when subjected to
hypercalcaemia. As an inhibitor of allergic
reactions, the ionic calcium is preferably used during
the triggering event of the immunocompetent cells; a
recommendation which is pract ically impossible. In
addition, the level at which this ion acts
meaningfully (18 mg%), is not advised to achieve due
to its mutagenic effect on the concerned cells.