The purpose of this study was to compare the cytotoxicity of an epoxy resin-based sealer (AH Plus) and a silicone-based sealer (Roeko Seal Automix, RSA). Cytotoxicity was assessed using the MTT assay for mitochondrial enzyme activity and haemocytometer viable cell counting after 24, 48 and 72-h exposure to L929 cells. AH Plus and RSA showed no statistically significant difference in the degree of toxicity. Both sealers had a low toxic influence on the cells during the experimental period. This study indicates that epoxy resin-based sealer AH Plus and the silicone-based sealer RSA have similar levels of cytotoxicity to mouse fibroblasts.

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Glutathione-S-transferases (GSTs) are enzymes involved in cellular detoxification by catalyzing the nucleophilic attack of glutathione (GSH) on the electrophilic center of numerous of toxic compounds and xenobiotics, including chemotherapeutic drugs. Human GST P1-1, which is known as the most prevalent isoform of the mammalian cytosolic GSTs, is overexpressed in many cancers and contributes to multidrug resistance by directly conjugating to chemotherapeutics. It is suggested that this resistance is related to the high expression of GST P1-1 in cancers, thereby contributing to resistance to chemotherapy. In addition, GSTs exhibit sulfonamidase activity, thereby catalyzing the GSH-mediated hydrolysis of sulfonamide bonds. Such reactions are of interest as potential tumor-directed prodrug activation strategies. Herein we report the design and synthesis of some novel sulfonamide-containing benzoxazoles, which are able to inhibit human GST P1-1. Among the tested compounds, 2-(4-chlorobenzyl)-5-(4-nitrophenylsulfonamido)benzoxazole (5 f) was found as the most active hGST P1-1 inhibitor, with an IC50 value of 10.2 μM, showing potency similar to that of the reference drug ethacrynic acid. Molecular docking studies performed with CDocker revealed that the newly synthesized 2-substituted-5-(4-nitrophenylsulfonamido)benzoxazoles act as catalytic inhibitors of hGST P1-1 by binding to the H-site and generating conjugates with GSH to form S-(4-nitrophenyl)GSH (GS-BN complex) via nucleophilic aromatic substitution reaction. The 4-nitrobenzenesulfonamido moiety at position 5 of the benzoxazole ring is essential for binding to the H-site and for the formation of the GST-mediated GSH conjugate.

Primary hyperoxaluria type 1 is a rare autosomal-recessive disease caused by the deficient activity of the liver specific enzyme alanine-glyoxylate aminotransferase. Increased endogenous oxalate production induces severe hyperoxaluria, recurrent urolithiasis, progressive nephrocalcinosis and renal failure. Here we report a 6 month old boy who presented with vomiting and decreased urine volume. He was diagnosed with chronic kidney failure at 4 months of age and peritoneal dialysis was introduced at a local hospital. His parents were third degree cousins and family history revealed 2 maternal cousins who developed end stage renal disease during childhood. When he was admitted to our hospital, laboratory studies were consistent with end stage renal disease, ultrasound showed bilateral massive nephrocalcinosis. As clinical presentation was suggestive for primary hyperoxaluria type 1, plasma oxalate was determined and found extremely elevated. Genetic testing proved diagnosis by showing a disease causing homozygous mutation (AGXT-gene: c.971_972delT). The patient was put on pyridoxine treatment and aggressive dialysis programme. In conclusion; progressive renal failure in infancy with massive nephrocalcinosis, especially if accompanied by consanguinity and family history, should always raise the suspicion of PH type 1. Increased awareness of the disease would help physicians in both treating the patients and guiding the families who have diseased children and plan to have further pregnancies.

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