موجز عن البحث:
|
The
purpose of the study was to compare the accuracy of breast MRI and
ultrasonography in assessing the tumor focality and tumor size of newly
diagnosed non-high risk breast cancer patients.
METHODS:
The
tumor focality status and the maximal tumor diameter by MRI and
ultrasonography were retrospectively compared with the corresponding
histopathological findings as reference. Test characteristics concerning the
tumor focality status were calculated. Bland-Altman plots were generated to
evaluate the agreement of the tumor size measurements by imaging and
histopathology. The t-test for dependent samples and the Fisher exact test
were used to test differences between groups for statistical significance.
The Pearson correlation coefficient r was calculated to measure the degree of
association between the tumor diameter by imaging and histopathology.
RESULTS:
Sixty-four
patient diagnosed between 2011 and 2013 were analyzed. MRI showed a good
sensitivity of 83% for detecting multifocal disease (ultrasonography, 75%).
The positive predictive value was 67% and the ratio of true-positive to
false-positive findings 2.0. MRI showed better limits of agreement (-21 to 26
mm versus -29 to 26 mm) and a better correlation (r=0.77 versus r=0.66) with
the histopathological tumor diameter compared to ultrasonography. The mean
differences between the tumor diameter by MRI and histopathology and
ultrasonography and histopathology were not significantly different (p=0.09).
The T classification (T1a, T1b, T1c, T2, T3) was correctly estimated by MRI
in 43 patients (67.2%) and by ultrasonography in 39 patients (60.9%)
(p=0.58).
CONCLUSION:
In our patient cohort only a modest diagnostic advantage of
MRI compared to ultrasonography could be detected.
|
ملخص المشاركة:
|
Blood shortage is one of the major global concerns as there
is a significant imbalance in donations comparing to transfusion demands,
which encouraged researchers to develop appropriate substitutes for donated
blood using pluripotent stem cells. There has been a rising excitement lately
that human induced pluripotent stem cells (iPS cells) could provide
patient-specific cells for cellular therapy in addition to their differentiation
capability into any cell type, which can be exploited in erythroid cell
production. Erythropoiesis is the process of making erythrocytes that can be
enhanced by hypoxia-inducible factors 1-alpha (HIF-1α), a transcription
factor known to facilitates cellular adaptation to hypoxia by over-expressing
specific genes and stimulating many metabolic processes, including
erythropoiesis, and angiogenesis.
In this study, we have established a novel protocol to
generate erythroid cells from human iPS cells using HIF-1α as a key enhancer.
Beside the use of the standard cytokine cocktail used for erythroid
induction; Epo, SCF, FLT3, TPO, IL3, and IL6, other growth factors were used;
BMP4, VEGF, FGF, in addition to 5% serum. Supplementing the cells in 2D
culture system with our novel optimized concentrations of the said cocktail
under hypoxic condition showed the highest yield erythroid markers, mainly
CD235a.
Further maturation of those cells is required in order to
achieve fully mature and functional RBCs phenotype. These results must be
supported by the detection of Rh type and ABO grouping to ensure the presence
of RBCs antigens. Eventually, after optimizing an enucleation protocol,
globin detection and O2 equilibrium curve must be also made to ensure
functionality of the hemoglobin (incomplete work).
Thus,
considering all the above, the ultimate aim of this study is the efficient
production of mature and functional RBCs in vitro from patient-specific iPS
cells using HIF-1α to facilitate erythroid progenitor maturation and
proliferation.
|
ملخص المشاركة:
|
Current
protocols used in the differentiation of human induced pluripotent stem cells
(hiPSCs) and human embryonic stem cells (hESCs) toward erythropoiesis utilize
two main approaches; Embryoid Body (EB) formation, which influences
heterogeneity of the produced population, and/or co-culture with mouse
stromal cells, where obstacles of purification of the cells rise which makes
the xeno-free culture requirement difficult to achieve, in addition to the
cytokines supplements. Moreover, these protocols reported low efficiency in
number and functionality, especially with hiPSCs, and required long time in
culture.In this study, we designed an experiment on the differentiation of
hiPSCs toward erythroid cells under hypoxia condition bypassing the EB
formation step and no co-culture system was required. Hypoxia condition is a
key enhancer for erythropoiesis and the activation of transferrin receptor
and iron uptake. Our protocol involve three steps: 1) Hematopoietic
induction, which starts with low serum condition (3-5%) with the addition of
BMP4, VEGF, bFGF, to trigger the mesodermal formation, in addition to
standard hematopoietic cytokines cocktails. i.e. Epo, SCF, FLT3, TPO, IL3,
and IL6; followed by 2) erythroid differentiation by supplementing the cells
with reduced number of cytokines; EPO, SCF and IL-3; and the final
differentiation step 3) maturation of erythroid progenitors by exposing cells
to EPO only.Early 7 days of culture showed an expression of an early
hematopoietic marker, CD34 (19%) followed by a high expression of CD45 (88%)
by day 14, which is a pan leukocyte marker in parallel to less expression of
an early erythroid marker, CD71 (20%). Over the culture period, an increase
in the expression of a late erythroid marker, CD235a was monitored that
reached (55%) by the end of our 4-weeks culture protocol.Further studies on
functional and morphological analysis using CFU assay and Wright-Giemsa
staining on day 7 and day 14 showed that the cell population on day 14 were
able to form hematopoietic colonies with relatively high formation of
erythroid progenitor colonies, i.e. BFU-Es as compared to day 7. Positive
expression of 3,3′-diaminobenzidine (DAB) staining showed the presence of
heme-containing proteins in 4-weeks cells, which later confirmed by detection
of relatively high haemoglobin expression from immunostaining. Interestingly,
staining with new methylene blue confirmed the reticulocytes morphology which
indicates a partial maturation process has successfully achieved within
4-week of culture. Further studies on maturation and enucleation of those
cells are required in order to achieve fully mature and functional RBCs
phenotype. Herein, we presented a direct and straight forward differentiation
protocol toward erythoid cells using hiPSCs in feeder-free system, bypassing
EB-stage resulting on high efficiency of erythroid cells formation within 4
weeks of culture, which include partial maturation under hypoxia condition.
|