A Review of Phytoplankton Composition Within Chesapeake Bay and Its Tidal Estuaries

Based on a continuous 20-year data base ofmonthly sampling in Chesapeake Bay and tidal regions of its major tributaries, 1454 phytoplankton taxa have been identified in these waters. They represent a diverse assemblage of species with a dominant diatom flora throughout the year, in addition to large seasonal representation by chlorophytes, cyanobacteria, cryptophytes and dinoflagellates. Included among this flora were 34 potential harmful or toxin producing species. The phytoplankton compositions associated with the seasonal successional patterns are discussed, in addition to characterizing the dominant floral relationships, with comparison to early composition records within the Bay. Several of the present day most common taxa were similar to those reported in sediment cores from the Bay dating to periods prior to European settlement. Comparison with collections made ~8 decades ago (1916–1922) within Chesapeake Bay indicated several of the same dominant flora remain dominant today; however, their cell concentrations are now significantly greater along with an increased diversity of species compared with these earlier studies

Anhydrous polymeric zinc(II) penta­noate

The structure of the title compound, poly[di-μ-penta­noato-zinc(II)], [Zn{CH3(CH2)3COO}2]n, consists of a three-dimensional polymeric layered network with sheets parallel to the (100) plane, in which tetra­hedrally coordinated zinc(II) ions are connected by penta­noate bridges in a syn–anti arrangement. The hydro­carbon chains are in the fully extended all-trans conformation and are arranged in a tail-to-tail double bilayer

Atypical Melanocytic Proliferations and New Primary Melanomas in Patients With Advanced Melanoma Undergoing Selective BRAF Inhibition

Purpose Selective inhibition of mutant BRAF by using class I RAF inhibitors in patients with metastatic melanoma has resulted in impressive clinical activity. However, there is also evidence that RAF inhibitors might induce carcinogenesis or promote tumor progression via stimulation of MAPK signaling in RAF wild-type cells. We analyzed melanocytic lesions arising under class I RAF inhibitor treatment for dignity, specific genetic mutations, or expression of signal transduction molecules. Patients and Methods In all, 22 cutaneous melanocytic lesions that had either developed or considerably changed in morphology in 19 patients undergoing treatment with selective BRAF inhibitors for BRAF-mutant metastatic melanoma at seven international melanoma centers within clinical trials in 2010 and 2011 were analyzed for mutations in BRAF and NRAS genes and immunohistologically assessed for expression of various signal transduction molecules in comparison with 22 common nevi of 21 patients with no history of BRAF inhibitor treatment. Results Twelve newly detected primary melanomas were confirmed in 11 patients within 27 weeks of selective BRAF blockade. In addition, 10 nevi developed of which nine were dysplastic. All melanocytic lesions were BRAF wild type. Explorations revealed that expression of cyclin D1 and pAKT was increased in newly developed primary melanomas compared with nevi (P = .01 and P = .03, respectively). There was no NRAS mutation in common nevi, but BRAF mutations were frequent. Conclusion Malignant melanocytic tumors might develop with increased frequency in patients treated with selective BRAF inhibitors supporting a mechanism of BRAF therapy–induced growth and tumorigenesis. Careful surveillance of melanocytic lesions in patients receiving class I RAF inhibitors seems warranted