9 research outputs found
Altered expression of microRNA-451 in eutopic endometrium of baboons ( Papio anubis ) with endometriosis
Are microRNAs (miRs) altered in the eutopic endometrium (EuE) of baboons following the induction of endometriosis
Study of pyruvate kinase activity in human astrocytomas - Alanine-inhibition test revisted
Background: Recent studies have confirmed that alterations in the
isoenzyme of pyruvate kinase (PK) provide tumor cells with selective
growth advantage. Aims: Our aim was to establish the mean activity of
the enzyme PK in human astrocytomas and to look for any trends in the
activity with relation to histological grade. Materials and Methods:
The PK (EC 2.7.1.40) activity was measured in the tumor homogenate by
spectrophotometric rate determination. ΔAbsorbance at 340 nm (A
340nm ) per minute was obtained using the maximal linear rate for both
the test and the blank. Enzyme activity was estimated in the presence
and absence of amino acid alanine. Results: The mean PK level in
astrocytomas was 3.5 ± 2.0 mmol/min/mg protein, which was
significantly higher (24%; P < 0.001) when compared to 2.8 ±
0.3 mmol/min/mg protein in control brain. Highest PK activity was noted
in grade 2 astrocytomas. In controls there was no change in PK activity
in the presence of alanine. In grade 2 astrocytomas there was 7%
decrease in mean PK activity in the presence of alanine, this
difference in grade 3 astrocytomas was 33% and in grade 4 astrocytomas
it was 61%. As the tumors were becoming malignant there was a graded
increase in the levels of PK inhibition. Conclusions: Mean PK activity
was significantly higher in astrocytomas. There was a graded increase
in level of PK inhibition as the tumors were becoming more malignant