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3 results on '"Randolph Duverna"'

1. A Survey of the Levels of Selected Metals in U.S. Meat, Poultry, and Siluriformes Fish Samples Taken at Slaughter and Retail, 2017–2022

Author

Katie Weyrauch, Randolph Duverna, Patrick N. Sisco, Alexander Domesle, and Iva Bilanovic

Subjects
Catfish, Meat, Metals, National Residue Program, Poultry, Siluriformes, Food processing and manufacture, TP368-456, Nutrition. Foods and food supply, TX341-641
Abstract

The U.S. Department of Agriculture (USDA) Food Safety and Inspection Service (FSIS) conducts surveillance of metallic elements in U.S. meat, poultry, and Siluriformes fish samples collected immediately postmortem as part of its National Residue Program (NRP). From 2017 to 2022, 13,966 samples were analyzed under the NRP. The Federal Emergency Response Network (FERN) Cooperative Agreement Program (CAP) tests meat, poultry, and Siluriformes fish products collected at retail in the United States for metals. From 2018 to 2022, 2,902 samples were analyzed by FERN CAP laboratories. Meat and poultry samples collected by FSIS show that most metals were not detected at all or were detected infrequently. Meat is a rich source of iron and zinc, and iron was detected in 22% (1,255/5,623) and zinc was detected in 48% (2,742/5,676) of meat and poultry samples, respectively. The percentage of samples testing positive for manganese, molybdenum, lead, and cadmium were higher in the FERN CAP retail samples than in FSIS samples. Expected human exposure from average levels of lead and cadmium found in meat and poultry was compared to toxicological reference values and was not found to exceed these values. Detections of arsenic and mercury were found more often in Siluriformes fish samples (2017–2022) than in terrestrial animals. Trace amounts of arsenic and mercury were detected in 8% and 4% of Siluriformes samples, respectively, but were not detected at levels that raise concern. On the whole, both the FSIS and FERN CAP datasets provide reassuring evidence of the safety of the FSIS-regulated food supply with regard to the studied elements.

Published
2024
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2. Polyisoprenylated Methylated Protein Methyl Esterase: a Putative Biomarker and Therapeutic Target for Pancreatic Cancer

Author

Randolph Duverna, Felix Amissah, Nazarius S. Lamango, Byron J. Aguilar, Augustine T. Nkembo, Seth Y. Ablordeppey, and Rosemary A. Poku

Subjects
Models, Molecular, Antineoplastic Agents, Pharmacology, Esterase, Article, Structure-Activity Relationship, Prenylation, Pancreatic cancer, Cell Line, Tumor, Drug Discovery, medicine, Biomarkers, Tumor, Neoplasm, Humans, Molecular Targeted Therapy, Survival rate, EC50, Cell Proliferation, Cell Death, Dose-Response Relationship, Drug, Molecular Structure, Chemistry, Organic Chemistry, General Medicine, medicine.disease, Amides, Pancreatic Neoplasms, Biomarker (medicine), Signal transduction, Drug Screening Assays, Antitumor, Carboxylic Ester Hydrolases
Abstract

Pancreatic cancer is the most deadly neoplasm with a 5-year survival rate of less than 6%. Over 90% of cases harbor K-Ras mutations, which are the most challenging to treat due to lack of effective therapies. Here, we reveal that polyisoprenylated methylated protein methyl esterase (PMPMEase) is overexpressed in 93% of pancreatic ductal adenocarcinoma. We further present polyisoprenylated cysteinyl amide inhibitors (PCAIs) as novel compounds designed with structural elements for optimal in vivo activities and selective disruption of polyisoprenylation-mediated protein functions. The PCAIs inhibited PMPMEase with Ki values ranging from 3.7 to 20 μM. The 48 h EC50 values for pancreatic cancer Mia PaCa-2 and BxPC-3 cell lines were as low as 1.9 μM while salirasib and farnesylthiosalicylamide were ineffective at 20 μM. The PCAIs thus have the potential to serve as effective therapies for pancreatic and other cancers with hyperactive growth signaling pathways mediated by Ras and related G-proteins.

Published
2014

3. Polyisoprenylated Methylated Protein Methyl Esterase Is Both Sensitive to Curcumin and Overexpressed in Colorectal Cancer: Implications for Chemoprevention and Treatment

Author

Byron J. Aguilar, Randolph Duverna, Rosemary A. Poku, Nazarius S. Lamango, and Felix Amissah

Subjects
Curcumin, Article Subject, Colorectal cancer, Protein Prenylation, lcsh:Medicine, General Biochemistry, Genetics and Molecular Biology, 03 medical and health sciences, chemistry.chemical_compound, 0302 clinical medicine, medicine, Humans, Molecular Targeted Therapy, 030304 developmental biology, 0303 health sciences, General Immunology and Microbiology, biology, lcsh:R, Cancer, General Medicine, medicine.disease, Molecular biology, Enzyme assay, 3. Good health, Gene Expression Regulation, Neoplastic, Kinetics, chemistry, Caco-2, 030220 oncology & carcinogenesis, Cancer cell, biology.protein, Adenocarcinoma, Protein prenylation, Caco-2 Cells, Colorectal Neoplasms, Carboxylic Ester Hydrolases, Research Article
Abstract

Inhibition of PMPMEase, a key enzyme in the polyisoprenylation pathway, induces cancer cell death. In this study, purified PMPMEase was inhibited by the chemopreventive agent, curcumin, with aKiof 0.3 μM (IC50= 12.4 μM). Preincubation of PMPMEase with 1 mM curcumin followed by gel-filtration chromatography resulted in recovery of the enzyme activity, indicative of reversible inhibition. Kinetics analysis with N-para-nitrobenzoyl-S-trans,trans-farnesylcysteine methyl ester substrate yieldedKMvalues of 23.6 ± 2.7 and 85.3 ± 15.3 μM in the absence or presence of 20 μM curcumin, respectively. Treatment of colorectal cancer (Caco2) cells with curcumin resulted in concentration-dependent cell death with an EC50of 22.0 μg/mL. PMPMEase activity in the curcumin-treated cell lysate followed a similar concentration-dependent profile with IC50of 22.6 μg/mL. In colorectal cancer tissue microarray studies, PMPMEase immunoreactivity was significantly higher in 88.6% of cases compared to normal colon tissues(P<0.0001). The mean scores ± SEM were 91.7 ± 11.4 (normal), 75.0 ± 14.4 (normal adjacent), 294.8 ± 7.8 (adenocarcinoma), and 310.0 ± 22.6 (mucinous adenocarcinoma), respectively. PMPMEase overexpression in colorectal cancer and cancer cell death stemming from its inhibition is an indication of its possible role in cancer progression and a target for chemopreventive agents.

Published
2013

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