Publications by authors named "Zitomer N"

We examined the association between serum aflatoxin B1-lysine adduct (AFB1-lys) levels in pregnant women and adverse pregnancy outcomes (low birthweight, miscarriage and stillbirth) through a nested matched case-control study of pregnant women enroled at ≤28 weeks' gestation in Mombasa, Kenya, from 2017 to 2019. Cases comprised women with an adverse birth outcome, defined as either delivery of a singleton infant weighing <2500 g, or a miscarriage, or a stillbirth, while controls were women who delivered a singleton live infant with a birthweight of ≥2500 g. Cases were matched to controls at a ratio of 1:2 based on maternal age at enrolment, gestational age at enrolment and study site.

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Aflatoxin exposure is endemic in developing countries with warm, humid climates that promote toxigenic mold growth on crops and foodstuffs. Estimating human aflatoxin exposure is key to identifying and abating contamination sources. Serum aflatoxin B1 bound to albumin lysine (AFB1-lys) is a preferred exposure biomarker, but field sample collection, processing, transportation, and storage logistics are challenging.

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Aflatoxins are carcinogenic mycotoxins that contaminate a variety of crops worldwide. Acute exposure can cause liver failure, and chronic exposure can lead to stunting in children and liver cancer in adults. We estimated aflatoxin exposure across Uganda by measuring a serum biomarker of aflatoxin exposure in a subsample from the 2011 Uganda AIDS Indicator Survey, a nationally representative survey of HIV prevalence, and examined its association with geographic, demographic, and socioeconomic variables.

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Acute aflatoxin exposure can cause death and disease (aflatoxicosis) in humans. Aflatoxicosis fatality rates have been documented to be as high as 40% in Kenya. The inclusion in the diet of calcium silicate 100 (ACCS100), a calcium montmorillonite clay, may reduce aflatoxin bioavailability, thus potentially decreasing the risk of aflatoxicosis.

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This work developed a UHPLC-MS/MS method for the detection and quantitation of aflatoxins in smokeless tobacco products, which was then used to determine aflatoxin B1 concentrations in 32 smokeless tobacco products commercially available in the United States. Smokeless tobacco products were dried, milled, and amended with (13)C17-labeled internal standards, extracted in water/methanol solution in the presence of a surfactant, isolated through use of immunoaffinity column chromatography, and reconstituted in mobile phase prior to UHPLC-MS/MS analysis. The method was capable of baseline separation of aflatoxins B1, B2, G1, and G2 in a 2.

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Fumonisins (FB) are mycotoxins found in maize. They are hypothesised risk factors for neural tube defects (NTDs) in humans living where maize is a dietary staple. In LM/Bc mice, FB1-treatment of pregnant dams induces NTDs and results in increased levels of sphingoid base 1-phosphates in blood and tissues.

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Fusarium verticillioides produces fumonisin mycotoxins during the colonization of maize, and fumonisin B₁ (FB₁) production is necessary for manifestation of maize seedling blight disease. The objective of this study was to address FB₁ mobility and accumulation in seedlings to determine if proximal infection by F. verticillioides is necessary for FB₁ accumulation.

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Scope: Fumonisin (FB) intake can be high when maize is a dietary staple. We determined (i) urinary FB (UFB) in women consuming maize in high- and low-exposure communities in Guatemala, (ii) the FB levels in maize, (iii) the relationship between UFB and FB intake, and (iv) the relative excretion of UFB1 , UFB2 , and UFB3 .

Methods And Results: Urine and maize were analyzed for FB for 1 year in three departments.

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Urnucratins A-C (1-3), which possess an unusual bisnaphthospiroether skeleton with one oxygen bridge and one C-C bridge and represent a new subclass of bisnaphthalenes, were isolated from the North American cup fungus Urnula craterium. Their structures, including absolute configurations, were determined by means of HRMS, NMR, and quantum chemical CD calculations. Urnucratin A (1) was found to be active against methicillin-resistant Staphylococcus aureus, vancomycin-resistant Enterococcus faecium, and Streptococcus pyogenes with MIC values of 2, 1, and 0.

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The fungal toxin fumonisin B1 (FB1) is a potential human carcinogen based on evidence of renal carcinogenicity in rats and hepatocarcinogenicity in mice. The toxicity and carcinogenicity of FB1 is linked to ceramide synthase inhibition. Based on this mechanism of action and on lack of evidence of genotoxicity, FB1 is considered a non-genotoxic carcinogen.

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Scope: Fumonisins (FB) are mycotoxins found in maize. The purpose of this study was to (i) determine the relationship between FB(1) , FB(2) , and FB(3) intake and urinary excretion in humans, (ii) validate a method to isolate urinary FB on C(18) -SPE cartridges for international shipment, and (iii) test the method using samples from Guatemala.

Methods And Results: Volunteers (n = 10) consumed 206 grams/day of tortillas and biscuits prepared from masa flour and a product containing maize flour.

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The veA or velvet gene is necessary for biosynthesis of mycotoxins and other secondary metabolites in Aspergillus species. In addition, veA has also been demonstrated to be necessary for normal seed colonization in Aspergillus flavus and Aspergillus parasiticus. The present study shows that veA homologues are broadly distributed in fungi, particularly in Ascomycetes.

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In vivo and in vitro studies suggest a crucial role for Sphingosine 1-phosphate (S1P) and its receptors in the development of the nervous system. Dihydrosphingosine 1-phosphate (dhS1P), a reduced form of S1P, is an agonist at S1P receptors, but the pharmacology and physiology of dhS1P has not been widely studied. The mycotoxin fumonisin B1 (FB(1)) is a potent inhibitor of ceramide synthases and causes selective accumulation of dihydrosphingosine and dhS1P.

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Fumonisin mycotoxins are common contaminants in many grains, often at very low levels. Maize is -particularly problematic as one of the organisms that commonly produce fumonisins, the fungus Fusarium verticillioides, often exists as an endophyte of maize. Fumonisin is a potent inhibitor of the enzyme ceramide synthase, and this inhibition results in the accumulation of a variety of upstream compounds, most notably, the sphingoid bases sphingosine, sphinganine, 1-deoxysphinganine and, in plants, phytosphingosine.

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In an earlier study using maize seedlings grown from kernels inoculated with Fusarium verticillioides, fumonisin B(1) (FB(1)) was preferentially accumulated in leaf tissue compared to FB(2) and FB(3). The present study tested whether maize seedlings preferentially translocate FB(1) when plants are watered with FB(1) and/or FB(2), without the fungus present. The results show that neither FB(1) nor FB(2) was translocated when administered in the watering solution, and although both FB(1) and FB(2) were taken up by the roots, the accumulation of FB(2) in roots was significantly less than expected, indicating that FB(1) was preferentially accumulated.

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We constructed a two-locus database, comprising partial translation elongation factor (EF-1alpha) gene sequences and nearly full-length sequences of the nuclear ribosomal intergenic spacer region (IGS rDNA) for 850 isolates spanning the phylogenetic breadth of the Fusarium oxysporum species complex (FOSC). Of the 850 isolates typed, 101 EF-1alpha, 203 IGS rDNA, and 256 two-locus sequence types (STs) were differentiated. Analysis of the combined dataset suggests that two-thirds of the STs might be associated with a single host plant.

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Fumonisin B(1) (FB(1)) is a mycotoxin that inhibits ceramide synthases (CerS) and causes kidney and liver toxicity and other disease. Inhibition of CerS by FB(1) increases sphinganine (Sa), Sa 1-phosphate, and a previously unidentified metabolite. Analysis of the latter by quadrupole-time-of-flight mass spectrometry assigned an m/z = 286.

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The fungus Fusarium verticillioides is a pathogen of many plants and produces fumonisins. In addition to their well-studied animal toxicoses, these toxins contribute to the development of maize seedling disease in susceptible maize varieties. Fumonisin disruption of sphingolipid biosynthesis occurs during pathogenesis.

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The filamentous ascomycete Fusarium verticillioides is a pathogen of maize and produces the fumonisin mycotoxins. However, a distinct population of F. verticillioides is pathogenic on banana and does not produce fumonisins.

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Contractions of an echinoderm (sp. Sclerodactyla briareus) smooth muscle, the longitudinal muscle of the body wall (LMBW), were evoked by acetylcholine (ACh) and agonists: epibatidine, muscarine and nicotine (in order of force generation: ACh>muscarine=epibatidine>nicotine). ACh-induced contractions were blocked by atropine by 50%, and methoctramine, by 30%.

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Our experience with 58 percutaneous gallbladder procedures in 48 patients are discussed. Diagnostic procedures consisted of needle aspiration of bile (n = 5) to evaluate the gallbladder as a source of infections and transcholecystic cholangiography (TCC) (n = 32) for bile duct visualization. Percutaneous cholecystostomy (PC) (n = 21) was performed for gallbladder or bile duct decompression or stone dissolution.

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The authors describe their experience with methyl tertiary butyl ether (MTBE) in a larger series of patients than previously reported in order to acquaint physicians with both its effectiveness for dissolution of common bile duct calculi and the limitations of its use. Ten patients with 13 biliary calculi underwent percutaneous stone dissolution treatment with the experimental cholesterol solvent, MTBE. Three stones completely dissolved within 30 minutes, seven were reduced in size, and three were visibly unaffected.

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Seventeen patients underwent monooctanoin infusion and biliary stone removal through the percutaneous transhepatic biliary drainage tract. In the first five patients, monooctanoin was infused until the stone(s) became smaller or disappeared; basket extraction was not attempted until this reduction was observed. An average of 22 hospital days was required for the procedure.

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Percutaneous transcholecystic cholangiography was performed in 20 patients. Fifteen patients had normal-sized bile ducts on sonograms and computed tomographic scans, and five had partial common bile duct obstruction. Gallbladder pressures were measured in 14 patients.

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Small biliary calculi discovered after the T-tube track has closed can be removed with a percutaneous transhepatic biliary catheter. Mono-octanoin can be used to reduce the size of large calculi for percutaneous extraction.

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