109 research outputs found
Placenta-specific methylation of the vitamin D 24-hydroxylase gene: implications for feedback autoregulation of active vitamin D levels at the fetomaternal interface
Plasma concentrations of biologically active vitamin D (1,25-
(OH)2D) are tightly controlled via feedback regulation of renal
1-hydroxylase (CYP27B1; positive) and 24-hydroxylase
(CYP24A1; catabolic) enzymes. In pregnancy, this regulation is
uncoupled, and 1,25-(OH)2D levels are significantly elevated,
suggesting a role in pregnancy progression. Epigenetic regulation
of CYP27B1 and CYP24A1 has previously been described in
cell and animal models, and despite emerging evidence for a
critical role of epigenetics in placentation generally, little is
known about the regulation of enzymes modulating vitamin D
homeostasis at the fetomaternal interface. In this study, we
investigated the methylation status of genes regulating vitamin
D bioavailability and activity in the placenta. No methylation of
the VDR (vitamin D receptor) and CYP27B1 genes was found in
any placental tissues. In contrast, the CYP24A1 gene is methylated
in human placenta, purified cytotrophoblasts, and primary
and cultured chorionic villus sampling tissue. No methylation
was detected in any somatic human tissue tested. Methylation
was also evident in marmoset and mouse placental tissue. All
three genes were hypermethylated in choriocarcinoma cell
lines, highlighting the role of vitaminDderegulation in this cancer.
Gene expression analysis confirmed a reduced capacity for
CYP24A1 induction with promoter methylation in primary cells
and in vitro reporter analysis demonstrated that promoter
methylation directly down-regulates basal promoter activity
and abolishes vitamin D-mediated feedback activation. This
study strongly suggests that epigenetic decoupling of vitamin D
feedback catabolism plays an important role in maximizing
active vitamin D bioavailability at the fetomaternal interface
Performance of an endcap prototype of the ATLAS accordion electromagnetic calorimeter
The design and construction of a lead-liquid argon endcap calorimeter prototype using an accordion geometry and conceived as a sector of the inner wheel of the endcap calorimeter of the future ATLAS experiment at the LHC is described. The performance obtained using electron beam data is presented. The main results are an energy resolution with a sampling term below and a small local constant term, a good linearity of the response with the incident energy and a global constant term of 0.8\% over an extended area in the rapidity range of . These properties make the design suitable for the ATLAS electromagnetic endcap calorimeter
Autopercepción de la salud en adultos mayores asistentes al club de día del centro de jubilados y pensionados vaqueros. Salta
El Club de día es un dispositivo dirigido a los adultos mayores (AM) con exposición a diferentes grados de vulnerabilidad social y fragilización que pretende generar un espacio de pertenencia y contención social, mediante la implementación de un plan de actividades de multiestimulación
Autopercepción de la salud en adultos mayores asistentes al club de día del centro de jubilados y pensionados vaqueros. Salta
El Club de día es un dispositivo dirigido a los adultos mayores (AM) con exposición a diferentes grados de vulnerabilidad social y fragilización que pretende generar un espacio de pertenencia y contención social, mediante la implementación de un plan de actividades de multiestimulación
Impact of DNA methylation on trophoblast function
The influence of epigenetics is evident in many fields of medicine today. This is also true in placentology, where versatile epigenetic mechanisms that regulate expression of genes have shown to have important influence on trophoblast implantation and placentation. Such gene regulation can be established in different ways and on different molecular levels, the most common being the DNA methylation. DNA methylation has been shown today as an important predictive component in assessing clinical prognosis of certain malignant tumors; in addition, it opens up new possibilities for non-invasive prenatal diagnosis utilizing cell-free fetal DNA methods. By using a well known demethylating agent 5-azacytidine in pregnant rat model, we have been able to change gene expression and, consequently, the processes of trophoblast differentiation and placental development. In this review, we describe how changes in gene methylation effect trophoblast development and placentation and offer our perspective on use of trophoblast epigenetic research for better understanding of not only placenta development but cancer cell growth and invasion as well
Modification of conservative treatment of heterotopic cervical pregnancy by Foley catheter balloon fixation with cerclage sutures at the level of the external cervical os: a case report
<p>Abstract</p> <p>Introduction</p> <p>Conservative treatment of a heterotopic cervical pregnancy was performed with a modification of the fixation of a Foley catheter at the level of the external cervical os, followed by the ligature of the descending cervical branches of the uterine arteries and systemic methotrexate application.</p> <p>Case presentation</p> <p>A 34-year-old Caucasian woman was diagnosed with double gestation after 6 weeks of <it>in vitro </it>fertilization treatment. A gynecological examination and color Doppler ultrasound scan revealed intra-uterine and cervical gestational sacs both containing live fetuses. A Foley catheter balloon was inserted into the cervical canal, inflated and fixed by a cerclage suture at the level of the external cervical os, followed by ligation of the descending cervical branches of the uterine arteries. Systemic methotrexate was applied. Three days after removal of the Foley catheter, an evacuation of the intra-uterine gestational sac was performed. Hemorrhage from the implantation site was controlled immediately and a pregnancy termination was successfully performed. The procedure was uneventful and our patient was discharged with a preserved uterus.</p> <p>Conclusions</p> <p>Conservative treatment of cervical pregnancy using a Foley catheter balloon is more efficacious if the Foley catheter balloon is attached in the correct position with a cerclage suture at the level of the external os, followed by ligation of the descending cervical branches of the uterine arteries, thereby exerting maximal pressure on the bleeding vessels.</p
Discovery of DNA methylation markers in cervical cancer using relaxation ranking
<p>Abstract</p> <p>Background</p> <p>To discover cancer specific DNA methylation markers, large-scale screening methods are widely used. The pharmacological unmasking expression microarray approach is an elegant method to enrich for genes that are silenced and re-expressed during functional reversal of DNA methylation upon treatment with demethylation agents. However, such experiments are performed in <it>in vitro </it>(cancer) cell lines, mostly with poor relevance when extrapolating to primary cancers. To overcome this problem, we incorporated data from primary cancer samples in the experimental design. A strategy to combine and rank data from these different data sources is essential to minimize the experimental work in the validation steps.</p> <p>Aim</p> <p>To apply a new relaxation ranking algorithm to enrich DNA methylation markers in cervical cancer.</p> <p>Results</p> <p>The application of a new sorting methodology allowed us to sort high-throughput microarray data from both cervical cancer cell lines and primary cervical cancer samples. The performance of the sorting was analyzed <it>in silico</it>. Pathway and gene ontology analysis was performed on the top-selection and gives a strong indication that the ranking methodology is able to enrich towards genes that might be methylated. Terms like regulation of progression through cell cycle, positive regulation of programmed cell death as well as organ development and embryonic development are overrepresented. Combined with the highly enriched number of imprinted and X-chromosome located genes, and increased prevalence of known methylation markers selected from cervical (the highest-ranking known gene is <it>CCNA1</it>) as well as from other cancer types, the use of the ranking algorithm seems to be powerful in enriching towards methylated genes.</p> <p>Verification of the DNA methylation state of the 10 highest-ranking genes revealed that 7/9 (78%) gene promoters showed DNA methylation in cervical carcinomas. Of these 7 genes, 3 (<it>SST</it>, <it>HTRA3 </it>and <it>NPTX1</it>) are not methylated in normal cervix tissue.</p> <p>Conclusion</p> <p>The application of this new relaxation ranking methodology allowed us to significantly enrich towards methylation genes in cancer. This enrichment is both shown <it>in silico </it>and by experimental validation, and revealed novel methylation markers as proof-of-concept that might be useful in early cancer detection in cervical scrapings.</p
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