Role of Microsatellites Instability in Carcinogenesis of Postcricoid Carcinoma on Top of Plummer-Vinson Syndrome

To develop a molecular pattern that might help in understanding carcinogenesis of postcricoid carcinoma (PCC) on top of Plummer-Vinson syndrome (PVS) in a prospective controlled study. Twenty-four patients with PVS were diagnosed and followed up over a 4 year period, during which eight of them showed malignant change to PCC. Twenty volunteers free of neoplastic diseases were included as a control group. In the two groups, DNA extraction from mononuclear peripheral blood cells, and analysis of loss of heterozygosity (LOH) and microsatellite instability (MSI) using six paired simple tandem repeats (STRs) primers were done. The molecular weight of each STRs locus was scored and statistical correlations were performed. LOH occurred in 55.6 and 72.9% of PVS and PCC cases compared to 25% of control group. At loci D17S695, D9S753 and D9S171, LOH occurred in 54.2, 66.7, and 70.8% of PVS cases; and in 62.5% of PCC cases for each locus compared to 15, 25 and 45% of control cases. D3S1286 and CFS1-R displayed the highest frequency of LOH in PCC (100% for each) while recorded in 58.3 and 33.3% in PVS compared to 30 and 0% in control cases. Certain genetic events tend to occur as early and late events in malignant change of PVS to PCC. Detection of these events may help in understanding carcinogenesis and in early detection of malignancy. CFS1-R is the most informative marker of tumor progression

The Origin and MgCl2–NaCl Variations in an Athalassic Sag Pond: Insights from Chemical and Isotopic Data

The examination of past and new chemical–isotopic data (2H/1H–18O/16O,11B/10B and87Sr/86Sr ratios) shows the meteoric origin of the Sawa Lake (Muthanna Governorate, Iraq) and its connection with the local aquifers, which feed the lake via the groundwater emerging from its floor through fault systems. The chemical and isotopic evaporation models are traced by geochemical computer codes by using a different composition of some potential inflows to the lake (e.g., the Euphrates River and Dammam aquifer). The main product of the chemical evaporation models is gypsum, as confirmed by the mineralogical examination of the sediment and the surrounding outcrops. A strong18O–2H enrichment is a consequence of the evaporation effect in arid regions; δ18O–Cl models and δ11B = + 23.4‰ exclude the contribution of any seawater-derived fluids. This latter value along with87Sr/86Sr = 0.707989 suggests a mixed origin from the Eocene–Miocene aquifers. The isotope and chemical evaporation paths from the meteorically recharged sources match the lake composition. However, compositional switches from NaCl toward MgCl2occurred in the last decade and are related to post-drought periods, showing that the interaction of the recharging waters with the local soils (Na–Mg exchange and/or the leaching of the top layer salts) have a role in the chemical composition. This demonstrates that the lake is significantly influenced by climatic variations