William B Melchior

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The potent toxins ricin, abrin, and other ribosome-inactivating proteins deadenylate a specific base in 28S ribosomal RNA that destroys ribosomes and leads to cell death. We have taken advantage of the fact that reverse transcriptase preferentially inserts an adenine opposite to an abasic site in RNA to create a quantitative polymerase chain reaction (PCR)(More)
Fumonisin B1 is associated with various animal and human carcinomas and toxicoses, including leukoencephalomalacia, hepatocarcinoma, pulmonary edema and esophageal carcinoma. We have examined the cellular effects of fumonisin B1 in vitro using cellular model systems relevant to potential human target tissues. Although fumonisin B1 has been described as a(More)
Fumonisin B1 stimulates apoptosis in a variety of cell types and tissues. We examined the role of sphingolipid changes in fumonisin B1-stimulated apoptosis. Sphinganine accumulated rapidly, sphingosine levels remained unchanged, and ceramides decreased during fumonisin B1 exposure. Increased DNA fragmentation, decreased viability, and apoptotic morphology(More)
Systemic lupus erythematosus (SLE) has shown an association with high levels of prolactin, low levels of dehydroepiandrosterone (DHEA), and induction of inflammatory cytokines in the serum of patients with the disease. This preliminary study examined the relevance of a -1149G/T functional single-nucleotide polymorphism (SNP) (rs1341239) in the promoter of(More)
Carcinogenic arylamines typically undergo metabolic activation via N-hydroxylation followed in most instances by O-esterification. In this study, the ability of methyl-, dimethyl-, and ethylaniline constituents of tobacco smoke to undergo oxidation at the nitrogen atom was analyzed. In addition, the mutagenicity of the corresponding N-hydroxyalkylanilines(More)
The carcinogens N-acetoxy-2-acetylaminofluorene (N-acetoxy-AAF) and N-hydroxy-2-aminofluorene (N-hydroxy-AF) were incubated with calf thymus DNA to determine if reaction occurred preferentially with discrete regions within the DNA. Derivative melting profiles indicated that both compounds decreased satellite transitions and that N-acetoxy-AAF depressed the(More)
Since the ultimate carcinogen W-hydroxy-1-naphthylamine (N-HO-1-NA) reacts selectively with DMA at the O6 atom of the guanine base, an investigation of the consequences of this potentially mispairing lesion upon DMA structure was under taken. Fluorescence spectroscopic studies, which detected only the major N-HO-1-NA-O6-guanine adduct, showed that the(More)
Liver injury resulting from exposure to drugs and environmental chemicals is a major health problem. Endoplasmic reticulum stress (ER stress) is considered to be an important factor in a wide range of diseases, such as cancer, neurological and cardiovascular disease, diabetes, and inflammatory diseases. The role of ER stress in drug-induced and(More)