Epigenetic Regulation of Hematopoietic Stem Cells

Hematopoietic stem cells are endowed with a distinct potential to bolster self-renewal and to generate progeny that differentiate into mature cells of myeloid and lymphoid lineages. Both hematopoietic stem cells and mature cells have the same genome, but their gene expression is controlled by an additional layer of epigenetics such as DNA methylation and post-translational histone modifications, enabling each cell-type to acquire various forms and functions. Until recently, several studies have largely focussed on the transcription factors andniche factors for the understanding of the molecular mechanisms by which hematopoietic cells replicate and differentiate. Several lines of emerging evidence suggest that epigenetic modifications eventually result in a defined chromatin structure and an "individual" gene expression pattern, which play an essential role in the regulation of hematopoietic stem cell self-renewal and differentiation. Distinct epigenetic marks decide which sets of genes may be expressed and which genes are kept silent. Epigenetic mechanisms are interdependent and ensure lifelong production of blood and bone marrow, thereby contributing to stem cell homeostasis. The epigenetic analysis of hematopoiesis raises the exciting possibility that chromatin structure is dynamic enough for regulated expression of genes. Though controlled chromatin accessibility plays an essential role in maintaining blood homeostasis; mutations in chromatin impacts on the regulation of genes critical to the development of leukemia. In this review, we explored the contribution of epigenetic machinery which has implications for the ramification of molecular details of hematopoietic self-renewal for normal development and underlying events that potentially co-operate to induce leukemia.

Anesthetic concerns in a huge congenital sublingual swelling obscuring airway access

Presence of intraoral pathology poses a great challenge during management of pediatric airway. We report management of big intraoral cystic swelling physically occupying the entire oral cavity restricting access to airway. Preintubation aspiration of swelling was done to decrease its size and make room for airway manipulation, followed by laryngoscopy and intubation in lateral position. Airway patency is at risk in postoperative period also, in this case, though the swelling decreased in size postoperatively but presence of significant edema required placement of tongue stitch and modified nasopharyngeal airway. Case report highlights simple maneuvers to manage a difficult case

Prolonged priapism following single dose administration of sildenafil: a rare case report

A case of priapism following the consumption of a single dose of sildenafil is reported, A 25-year-old unmarried healthy man consumed non-prescribed 50 mg sildenafil purchased over the counter. He developed painful priapism 30 min after the drug intake that had lasted for 4 days [96 h] when he sought medical advice as an emergency. The corpus spongiosum and glans was soft and the corpus cavernosa was rigid. Winter's shunt was done. Fifteen milliliters of dark blood was aspirated with 16 G needle. Detumescence was achieved within 30 min. He was discharged after 12 h. On one month follow-up, he had normal morning erections. A genetic basis with cross-reactivity of PDE-3 in addition to PDE-5 resulting in a cumulative erection effect may be possible elucidation for this unwanted side effect in rare cases. However, the number of cases reported with this side effect is still too less to draw further conclusions