Early chromosome condensation by XIST builds A-repeat RNA density that facilitates gene silencing.

XIST RNA triggers chromosome-wide gene silencing and condenses an active chromosome into a Barr body. Here, we use inducible human XIST to examine early steps in the process, showing that XIST modifies cytoarchitecture before widespread gene silencing. In just 2-4 h, barely visible transcripts populate the large "sparse zone" surrounding the smaller "dense zone"; importantly, density zones exhibit different chromatin impacts. Sparse transcripts immediately trigger immunofluorescence for H2AK119ub and CIZ1, a matrix protein. H3K27me3 appears hours later in the dense zone, which enlarges with chromosome condensation. Genes examined are silenced after compaction of the RNA/DNA territory. Insights into this come from the findings that the A-repeat alone can silence genes and rapidly, but only where dense RNA supports sustained histone deacetylation. We propose that sparse XIST RNA quickly impacts architectural elements to condense the largely non-coding chromosome, coalescing RNA density that facilitates an unstable, A-repeat-dependent step required for gene silencing.

Folate Deficiency in an Urban Safety Net Population.

PURPOSE: Since mandatory fortification of grain products with folic acid in the United States in 1998, folate deficiency has become rare. Some have suggested that serum folate levels should be tested rarely in countries with mandatory folic acid fortification, given low rates of deficiency, high cost per deficiency diagnosis, and low rates of supplementation for those diagnosed as deficient. Given persistent racial, ethnic, and socioeconomic disparities in folate deficiency, these suggestions may not apply to all populations. We examine the rate at which serum testing detected folate deficiency in an urban safety net hospital and the characteristics of folate-deficient patients. METHODS: We reviewed the charts of all inpatients and emergency department patients with low serum folate results at a safety net hospital in Boston in 2018. We collected data concerning demographics, social determinants of health, clinical factors, and whether folate supplementation was prescribed. Finally, we performed a cost analysis. RESULTS: Of 1368 patients tested, 76 (5.5%) met criteria for folate deficiency. Overall, 86.8% of these patients were anemic, and 17.1% had macrocytic anemia; 42% were diagnosed with malnutrition. Common social determinants in folate-deficient patients included birth outside of the United States, homelessness, and alcohol use disorder. Of folate-deficient patients, 88% were newly prescribed folic acid supplementation at discharge. The estimated charge per deficient test was $1278. CONCLUSION: Compared with a nearby institution, serum folate testing at our safety net hospital detected deficiency at a higher rate, incurred a lower charge per deficient test, and was more likely to impact management.

5-Fluorouracil associated neurovascular toxicities.

Fluorouracil (5-FU) is a commonly used chemotherapeutic agent in many cancers. The widely reported adverse effects are infusion reactions, rash, fever, nausea, vomiting, peripheral neuropathy, and hepatic injury. However, there are limited data about its neurological side effects. Herein, we are reporting 3 cases of 5-FU induced neurovascular toxicities. Cerebral vasospasm with associated transient ischemia is a rare but significant adverse effect of the 5-FU. Stroke-like presentation makes timely recognition extraordinarily important. Differentiating stroke mimics is crucial as recombinant tissue plasminogen activator therapy should be given within a 4.5 hours window after an ischemic stroke. We suggest that 5-FU induced cerebral vasospasm can present with acute stroke-like symptoms. Physicians should be aware of stroke mimics as a differential diagnosis to spare their patients from unnecessary invasive and high-risk treatments.

Presence of t(11;14) in AL amyloidosis as a marker of response when treated with a bortezomib-based regimen.

The proteasome inhibitor, bortezomib, has become a backbone for the first line treatment of patients with AL amyloidosis who are not eligible for high dose melphalan and stem cell transplantation. The presence of t(11;14), seen in up to 40-60% of patients with AL amyloidosis, may be associated with poorer response when treated with bortezomib based regimens. This remains a critical distinction in light of recent evidence demonstrating favourable responses to BCL-2 inhibition with venetoclax in patients with t(11;14) in multiple myeloma. We report on 135 patients with newly diagnosed AL amyloidosis treated with a bortezomib-based regimen as first line therapy between 2013 and 2017. Treatment outcomes were compared between a cohort of patients with t(11;14) and those without the translocation. Forty-four patients had the presence of t(11;14). Five-year overall survival was 46% for those with t(11;14) and 72% in patients without this translocation (p = .026). The median haematologic event free survival was 17 months for patients with t(11;14) compared to 34 months without (p = .068). Haematologic response of VGPR or better was achieved in 41% of patients with t(11;14) vs 66% without t(11;14) (p = .012). Cardiac and renal responses to first line treatment with bortezomib-based regimens were also higher in patients without t(11;14). In conclusion, patients with AL amyloidosis and the presence of t(11;14) have inferior outcomes with respect to survival, as well as haematologic and organ responses, when treated with bortezomib-based regimens as first line therapy.