Igf2/H19 Imprinting Control Region (ICR): An Insulator or a Position-Dependent Silencer?

The imprinting control region (ICR) located far upstream of the H19 gene, in conjunction with enhancers, modulates the transcription of Igf2 and H19 genes in an allele-specific manner. On paternal inheritance, the methylated ICR silences the H19 gene and indirectly facilitates transcription from the distant Igf2 promoter, whereas on the maternal chromosome the unmethylated ICR, together with enhancers, activates transcription of the H19 gene and thereby contributes to the repression of Igf2. This repression of maternal Igf2 has recently been postulated to be due to a chromatin boundary or insulator function of the unmethylated ICR. Central to the insulator model is the site-specific binding of a ubiquitous nuclear factor CTCF which exhibits remarkable flexibility in functioning as transcriptional activator or silencer. We suggest that the ICR positioned close to the enhancers in an episomal context might function as a transcriptional silencer by virtue of interaction of CTCF with its modifiers such as SIN3A and histone deacetylases. Furthermore, a localised folded chromatin structure resulting from juxtaposition of two disparate regulatory sequences (enhancer ICR) could be the mechanistic basis of ICR-mediated position-dependent (ICR-promoter) transcriptional repression in transgenic Drosophila

The case for mild stimulation for IVF: recommendations from The International Society for Mild Approaches in Assisted Reproduction.

The practice of ovarian stimulation for IVF is undergoing a fundamental re-evaluation as recent data begin to successfully challenge the traditional paradigm that ovarian stimulation should be aimed at the retrieval of as many oocytes as possible, in the belief that this will increase pregnancy rates. An opposing view is that live birth rate should not be the only end-point in evaluating the success of IVF treatment and that equal emphasis should be placed on safety and affordability. The International Society for Mild Approaches in Assisted Reproduction (ISMAAR) committee has carried out an up-to-date literature search, with the evidence being graded according to the University of Oxford's Centre for Evidence-Based Medicine. The recommendations were formulated taking into account the quality of evidence on the efficacy, risk and cost of each intervention. ISMAAR recommends adopting a mild approach to ovarian stimulation in all clinical settings as an increasing body of evidence suggests that mild stimulation is as effective as conventional stimulation, while being safer and less expensive. Mild ovarian stimulation could replace conventional stimulation, thus making IVF safer and more accessible worldwide

Mild stimulation for in vitro fertilization

It has been proven that the use of high gonadotropin dose does not necessarily improve the final outcome of IVF. Mild ovarian stimulation is based on the principle of optimal utilization of competent oocytes/embryos and endometrial receptivity. There is growing evidence that the pregnancy or live birth rates with mild-stimulation protocols are comparable to those with conventional IVF; the cumulative pregnancy outcome has been shown to be no different, despite having fewer numbers of oocytes or embryos available with milder ovarian stimulation. Although equally effective, mild-stimulation IVF is associated with a greater safety profile, in terms of the incidence of ovarian hyperstimulation syndrome and venous thromboembolism. It is also found to be better tolerated by patients and less expensive. Emerging research evidence may lead to widespread acceptance of mild IVF, by both patients and IVF providers, and make IVF more accessible to women and couples worldwide

Mild stimulation for in vitro fertilization

It has been proven that the use of high gonadotropin dose does not necessarily improve the final outcome of IVF. Mild ovarian stimulation is based on the principle of optimal utilization of competent oocytes/embryos and endometrial receptivity. There is growing evidence that the pregnancy or live birth rates with mild-stimulation protocols are comparable to those with conventional IVF; the cumulative pregnancy outcome has been shown to be no different, despite having fewer numbers of oocytes or embryos available with milder ovarian stimulation. Although equally effective, mild-stimulation IVF is associated with a greater safety profile, in terms of the incidence of ovarian hyperstimulation syndrome and venous thromboembolism. It is also found to be better tolerated by patients and less expensive. Emerging research evidence may lead to widespread acceptance of mild IVF, by both patients and IVF providers, and make IVF more accessible to women and couples worldwide

CD34 positive-microgranular variant of acute promyelocytic leukemia in a child

Acute promyelocytic leukemia (APL) is a subtype of acute myeloid leukemia (AML) in which abnormal promyelocytes predominate. APL is rare in children (approximately 10% of childhood AML) and is characterized by a higher incidence of hyperleukocytosis, an increased incidence of microgranular morphology, the presence of balanced t(15;17)(q22;q11.2-12) translocation, and more frequent occurrence of the PML-RARα isoforms bcr 2 and bcr 3 compared to adults. The cytomorphology of microgranular variant blasts is obviously different from AML M3 blasts; these cells have a nongranular or hypogranular cytoplasm or contain fine dust-like cytoplasmic azurophil granules that may not be apparent by light microscopy. This case report emphasizes the importance of a high index of suspicion for the diagnosis of APL, the hypogranular variant in particular. They are responsive to differentiation therapy with all trans-retinoic acid and complete remission in seen in >80% cases

Absence of follicular phase defect in women with recurrent miscarriage.

OBJECTIVE : The study was designed to compare the follicular phase of women with recurrent pregnancy loss and a healthy control group. It is possible that a defective or aberrant follicular phase may be associated with poor oocyte quality leading to a production of an embryo with compromised quality and hence early pregnancy loss. DESIGN : Prospective case-control study. SETTING : A tertiary care hospital of Sheffield, UK. PATIENT(S): Thirty-four women with recurrent miscarriage and 10 women with no previous history of miscarriage and regular menstrual cycles (control group) were recruited. INTERVENTION(S): The characteristics studied included Doppler assessment of blood flow to the follicle and the endometrium. Simultaneously, serum concentrations of biochemical markers such as anti-Müllerian hormone, inhibin B, FSH, LH, and P were compared in the two groups. MAIN OUTCOME MEASURE(S) : Differences in the two groups. RESULT(S) : We were unable to detect significant differences in various biochemical and ultrasound measurements in the follicular phase between women with recurrent miscarriage and a control group; however, the expected correlation between ovarian and pituitary hormones, which was observed in the control group, was absent in women with recurrent miscarriage. CONCLUSION(S): There may be subtle derangements of the feedback mechanism responsible for regulation of follicle development in this group of women. However, there were no obvious differences in the follicular phase of women with recurrent miscarriage and a healthy control group.</p

In vitromaturation of human immature oocytes for fertility preservation

Cryopreservation of embryos, oocytes, or ovarian tissues is the main option for female fertility preservation. Oocyte cryopreservation has emerged as especially important: the dramatic increase in the number of infants born from vitrified oocytes indicates that it is becoming one of the most important intervention options. However, oocyte cryopreservation with standard controlled ovarian hyperstimulation may not be feasible for some cancer patients as there are serious concerns about the effect of ovarian stimulation with hormones on the risk of cancer recurrence. Also, urgent gonadotoxic cancer treatment may not allow sufficient time for a patient to undergo hormonal ovarian stimulation. Thus, immature oocyte retrieval from ovaries without ovarian stimulation followed by in vitro maturation and vitrification is a promising fertility preservation option for women who cannot undergo ovarian stimulation or cannot delay their gonadotoxic cancer treatment. Immature oocytes can be collected from the ovaries during both the follicular and luteal phases, which maximizes the possibility for fertility preservation. The combination of ovarian tissue cryopreservation with immature oocyte collection from the tissue followed by oocyte vitrification via in vitro maturation represents another promising approach of fertility preservation in young women with cancer. (Fertil Steril Ò 2013;-: ---