The value of synthetic linear epitope analogues of La/SSB for the detection of autoantibodies to La/SSB; specificity, sensitivity and comparison of methods

Aflatoxin M1 (AFM1) is the principal hydroxylated aflatoxin metabolite present in the milk of dairy cows fed a diet contaminated with aflatoxin B1, (AFB1) and the metabolite is also present in the milk of human nursing mothers consuming foodstuffs containing the toxin. AFM1 is usually considered to be a detoxification product of AFB1 and this appears warranted if the biological endpoints involved are carcinogenicity and mutagenicity. However, it may not be a valid conclusion in the case of cytotoxicity. The metabolism of AFM1 and AFB1 have been studied in vitro using human liver microsomes. Formation of primary metabolites associated with metabolic activation to the respective epoxides reflected the differences between the carcinogenic potentials of the two toxins and, similar to AFB1, the conjugation of AFM1 epoxide with reduced GSH was catalyzed by mouse, but not human liver cytosol. Although the majority of the binding of [3H]AFB1 to microsomal protein was dependent on metabolic activation, a high level of retention of [3H]AFM1 by microsomes, nonextractable in methanol and unrelated to metabolic activation, was observed. It appears possible that this property is related to the high cytotoxicity of AFM1. Experiments using human cell line cells either expressing or not expressing human cytochrome P450 enzymes in assays of acute toxicity (MTT assays) have demonstrated a directly toxic potential of AFM1 in the absence of metabolic activation, in contrast to AFB1. Caution therefore needs to be exercised in designating the formation of AFM1 as essentially detoxification when considering a biological response in which cytotoxicity may play a significant role, e.g., immunotoxicity.     

Effect of aflatoxin metabolism and DNA adduct formation on hepatocellular carcinoma among chronic hepatitis B carriers in Taiwan

BACKGROUND/AIMS: Aflatoxins (AFs) are established hepatic carcinogens in several animal species. This study was performed to establish whether aflatoxin exposure may affect the risk of developing hepatocellular carcinoma in chronic hepatitis B virus carriers. METHODS: Urinary AF metabolites were measured for 43 HCC cases and 86 matched controls nested in a cohort of 7342 men in Taiwan. Thirty hepatocellular carcinoma cases and 63 controls were also tested for AFB1-albumin adducts. RESULTS: There was a dose-response relationship between urinary AFM1 levels and risk of hepatocellular carcinoma in chronic hepatitis B virus carriers. Comparing the highest with the lowest tertile of urinary AFM1 levels, the multivariate-adjusted odds ratio (OR) was 6.0 (95% confidence interval (CI) = 1.2-29.0). The hepatocellular carcinoma risk associated with AFB1 exposure was more striking among the hepatitis B virus carriers with detectable AFB1-N7-guanine adducts in urine. Compared with chronic hepatitis B virus carriers who were negative for AFB1-albumin adducts and urinary AFB1-N7-guanine, no elevated risk was observed for those who were positive for either marker. But an extremely high risk of hepatocellular carcinoma among those having both markers was found (OR = 10.0, 95% CI = 1.6-60.9). The proportion of AFB1 converted to AFM1 decreased with the progress of liver disease, whereas the formation of AFP1 increased. The difference in patterns of AFB1 metabolite formation was an independent risk factor for hepatocellular carcinoma after adjustment for total AFB1 excretion. There was a synergistic interaction between glutathione S-transferase M1 genotype and AFB1 exposure in hepatocellular carcinoma risk. CONCLUSIONS: AFB1 intake and expression of enzymes involved in AFB1 activation/detoxification may play an important role in hepatitis B virus-related hepatocarcinogenesis.     

Survey of the occurrence of aflatoxin M1 in dairy products marketed in Italy

During 1995, 159 samples of milk, 97 samples of dry milk for infant formula, and 114 samples of yogurt were randomly collected in supermarkets and drug stores in four large Italian cities and checked for aflatoxin M1 (AFM1) by immunoaffinity column extraction and HPLC. AFM1 was detected in 136 (86%) of the milk samples (in amounts ranging from < 1 ng/liter to 108.5 ng/liter; mean level: 10.19 ng/liter), in 81 (84%) of the dry milk samples (in amounts ranging from < 1 ng/liter to 101.3 ng/kg; mean level: 21.77 ng/kg), and in 91 (80%) of the yogurt samples (in amounts ranging from < 1 ng/liter to 496.5 ng/liter; mean level: 18.08 ng/liter). Altogether, only two samples of milk, two samples of yogurt, and one sample of dry milk had levels of AFM1 exceeding the Swiss legal limits, which are the most restrictive in the world. AFM1 contamination levels in milk and yogurt samples collected in the period of November to April were ca. four times as high as those in samples collected in the period of May to October. It is concluded that during 1995, despite the widespread occurrence of AFM1, the mean contamination levels in dairy products sold in Italy were not a serious human health hazard.     

Classification exposure error in studies on tobacco smoke in pregnancy and birth weight of newborns]

In this paper, the on-line coupling of solid-phase extraction, based on a restricted-access support with liquid chromatography-mass spectrometry (LC-MS), for the analysis of biological samples is described. The system was tested with cortisol and prednisolone for plasma analysis and arachidonic acid for urine analysis. A precolumn packed with a 25-micron C18 alkyl-diol support is used for direct plasma or urine injection. Using column-switching techniques, the analytes enriched on the precolumn are eluted to the analytical column without transfer loss. An on-line heart-cut technique was employed and only the analyte-containing fraction eluting from the LC column is directed to the MS to protect the LC-MS interface and ion-source from contamination. The whole system is operated in a parallel mode, that is, sample pre-treatment and LC-MS analysis are performed simultaneously to provide the shortest possible analysis time. The only off-line sample pre-treatment step required was centrifugation to remove particulate matter. With the fully automated system, total analysis times of 5 and 9.5 min were achieved for cortisol in serum and arachidonic acid in urine, respectively. Cortisol and related compounds were quantitatively recovered from plasma with a detection limit for prednisolone (direct injection of 100 microliters on restricted-access precolumn) of 2 ng/ml.     

Calmodulin-dependent protein kinases mediate calcium-induced slow motility of mammalian outer hair cells

A sensitive, simple and rapid method without sample pretreatment is presented for the simultaneous determination of flunitrazepam and its main metabolites (norflunitrazepam, 7-amino- and 7-acetamidoflunitrazepam) in urine. The single-step procedure is based on a column-switching technique which uses an immobilized antibody in an extraction column following concentration on a precolumn and separation on an analytical column. UV detection was performed at 254 nm. The reusability of the antibody exceeds 88 runs and a complete analysis was performed in less than 40 min. The method shows coefficients of variation below 9.9% and rates of recovery greater than 92% tested at the level of 50 ng/ml urine. The limit of detection was below 2 ng/ml urine for the four compounds.     

Oral platelet aggregation inhibitor Ro 48-3657: determination of the active metabolite and its prodrug in plasma and urine by high-performance liquid chromatography using automated column switching

A sensitive and highly automated high-performance liquid chromatography (HPLC) column-switching method has been developed for the simultaneous determination of the active metabolite III and its prodrug II, both derivatives of the oral platelet inhibitor Ro 48-3657 (I), in plasma and urine of man and dog. Plasma samples were deproteinated with perchloric acid (0.5 M), while urine samples could be processed directly after dilution with phosphate buffer. The prepared samples were injected onto a pre-column of a HPLC column switching system. Polar plasma or urine components were removed by flushing the precolumn with phosphate buffer (0.1 M, pH 3.5). Retained compounds (including II and III) were backflushed onto the analytical column, separated by gradient elution and detected by means of UV detection at 240 nm. The limit of quantification for both compounds was 1 ng/ml (500 microl of plasma) and 25 ng/ml (50 microl of urine) for plasma and urine, respectively. The practicability of the new method was demonstrated by the analysis of about 6000 plasma and 1300 urine samples from various toxicokinetic studies in dogs and phase 1 studies in man.     

Direct synthesis of aflatoxin B1-N7 guanine adduct: a reference standard for biological monitoring of dietary aflatoxin exposure in molecular epidemiological studies

Aflatoxin B1-N7-guanine and aflatoxin B1-human serum albumin adducts have been established as biomarkers of dietary aflatoxin exposure in epidemiological studies. Earlier chemical oxidants were used to synthesize aflatoxin B1-8,9-epoxide in vitro and its subsequent interaction with DNA or synthetic oligodeoxynucleotide was used as a source of authentic aflatoxin B1-N7-guanine adduct. In the present communication we report a simple single step procedure for the synthesis of aflatoxin B1-N7-guanine adduct using free guanine and m-chloroperbenzoic acid as the chemical oxidant for the production of AFB1-8,9-epoxide. At a molar ratio of 1:1 of AFB1-8,9-epoxide and guanine the recovery of the AFB1-N7-guanine adduct was found to be 60% while at higher molar ratios (1:2 and 1:4) of guanine the recovery of the AFB1-N7-guanine adduct was found to be low (30-40%). HPLC analysis of the AFB1-N7 guanine adduct showed a retention time identical with the retention time of the AFB1-N7-guanine adduct synthesized using calf thymus DNA. TLC-fluorodensitometric analysis indicated that the Rf of the AFB1-N7-guanine adduct was zero. Spectral analysis of the adduct synthesized showed an excitation wavelength of 360 nm and emission wavelength at 440 nm in phosphate buffer (100 mM, pH 7.4). Further, the formation of the AFB1-N7-guanine adduct was confirmed by perchloric acid treatment resulting in the destruction of the adduct. The AFB1-N7-guanine adduct thus synthesized was stable in both acidic as well as lyophilized conditions over a period of 2 weeks. The antibody capture assay showed that the antibodies produced against the antigen BSA-guanine-N7-AFB1 also cross-reacted with calf thymus DNA-AFB1 adduct, indicating specificity to the guanine-N7-AFB1 moiety. The method developed may find immediate application as a source of authentic reference standard in molecular epidemiological studies.     

Robotic automated analysis of foods for aflatoxin

Immunoaffinity column-based sample preparation procedures for determination of aflatoxins B1, B2, G1, and G2 in several food matrixes and aflatoxin M1 in milk have been automated by using flexible automation, or robotics. Components used to assemble the system were purchased commercially or developed and built in-house. A liquid-level sensor developed in-house to assist elution of the immunoaffinity column is described. After immunoaffinity column cleanup, aflatoxins are separated by reversed-phase liquid chromatography and determined by fluorescence without derivatization. Mean recoveries of aflatoxins B1, B2, and G1 added to corn and nuts at 9-36 ng/g total aflatoxins were > 85% (coefficient of variation [CV] = 16%). Recoveries of aflatoxin G2 averaged 50% (CV = 28%). Recoveries of aflatoxin M1 added to milk at 0.12-0.50 ng/mL averaged 78% (CV = 19%). The ability of the automated system to reproduce its results is demonstrated by the fact that the CV of replicate assays is generally better than 10%. Comparability between the automated procedure and the AOAC official method is demonstrated.     

Coupled-column liquid chromatographic analysis of catecholamines, serotonin, and metabolites in human urine

A column-switching HPLC system was utilized for the simultaneous determination of epinephrine, norepinephrine, dopamine, serotonin, and their metabolites metanephrine, normetanephrine, 3, 4-dihydroxyphenylacetic acid, homovanillic acid, and 5-hydroxyindoleacetic acid in human urine. The sample was injected directly onto a C18-alkyl-diol silica precolumn, which separated the analytes from matrix. The analytes were eluted from the precolumn onto the analytical column by the use of column-switching techniques and were then separated on the analytical column by means of ion-pair reversed-phase HPLC. The analytes were then oxidized to the corresponding quinones and converted into fluorescent derivatives by reaction with meso-1,2-diphenylethylenediamine.     

House dust mite allergens. A major risk factor for childhood asthma in Australia

A fully automated column-switching high-performance liquid chromatographic (HPLC) method was developed for the quantification of finasteride [N-(1,1-dimethylethyl)-3-oxo-4-aza-5 alpha-androst-1-ene-17 beta- -carboxamide] in human plasma. Plasma samples were diluted with an equal volume of ethylene glycol-water (40:60, v/v), then the diluted sample (150 microliters) was injected into the HPLC system without clean-up. The analyte was retained on a pretreatment column, whereas plasma proteins and other endogenous components were washed out to waste. The analyte was transferred to the analytical column in the heart-cut mode and then detected at 210 nm. A quantification limit of 1 ng/ml was attained. There was a linear relationship between peak height and drug concentration in plasma in the range 1-50 ng/ml. This method was validated and applied to the assay of plasma samples to characterize pharmacokinetic parameters in clinical studies.     

In vivo and in vitro studies on the stereoselective hydrolysis of tri- and diglycerides by gastric and pancreatic lipases

These studies were conducted to investigate whether ascorbic acid protected guinea pigs from aflatoxin B1 (AFB1) toxicity. Young guinea pigs, fed either 0 (AA) or 25 mg (25 AA) or gavaged 300 mg ascorbic acid (300 AA) per day for 21 days, were gavaged with the LD50 dose of AFB1 on the 22nd day. Seven out of 10 animals in the AA group died within 72 hr of AFB1 administration. The livers of the animals showed regional massive necrosis and multilobular degeneration. There was no mortality in the 25 AA group. Their livers, however, showed changes similar to those seen in AA group. Serum alanine amino transferase (ALAT) and aspartate amino transferase (ASAT) levels were elevated. There was neither mortality nor pathological changes in livers in the 300 AA group. Their ALAT and ASAT levels were unaffected. In vitro production of AFM1 by liver microsomes tended to be higher than that in the other two groups. Three animals saved from the 300 AA group and continued with their supplementation were administered a second, intraperitoneal (ip) LD50 dose of AFB1 1 month after the first AFB1 dose. One animal died. Livers of the animals showed centrilobular degeneration and moderate necrosis in scattered hepatocytes. Liver microsomal cytochrome P450 and cytosolic glutathione S-transferase (GST) levels and AFM1 production were drastically reduced. ALAT and ASAT activities were raised. The results indicated that intake of 300 mg of ascorbic acid almost protected the animals from acute toxicity of AFB1 when given by gavage, but not when administered as a second dose ip.     

Stereoselective determination of unchanged and glucuroconjugated eliprodil, a new anti-ischaemic drug, in human plasma and urine by precolumn derivatization and column-switching high-performance liquid chromatography with fluorescence detection

An HPLC method was developed and validated for the determination in human plasma and urine of the enantiomers of eliprodil, (+/-)-alpha-(4-chlorophenyl)-4[(4-fluorophenyl) methyl]piperidine-1-ethanol hydrochloride, a new anti-ischaemic agent administered as a racemate. Both enantiomers are present in human plasma in unchanged and glucuroconjugated form, whereas only the glucuroconjugated form is excreted into urine; as a consequence, such metabolites in human plasma and urine should be submitted to enzymatic deconjugation with beta-glucuronidase (Escherichia coli) before being extracted. The general method involves a liquid-liquid extraction of eliprodil and internal standard from alkalinized plasma or urine with n-hexane, evaporation of the organic phase and derivatization with (S)-(+)-naphthylethyl isocyanate to give carbamate diastereoisomeric derivatives of (S)-(+)- and (R)-(-)-eliprodil and internal standard; after evaporation of the derivatizing mixture and dissolution of the residue in a small volume of phosphate buffer-acetonitrile (60:40, v/v), an aliquot is injected into a column-switching HPLC system. The derivatized sample extract is purified on a precolumn filled with C8-bonded silica material, which is flushed with acetonitrile-water, then diastereoisomers of eliprodil and the internal standard are automatically transferred by the mobile phase to the analytical column. The analytical column is a C8 type, specially deactivated for basic compounds, the mobile phase is 0.025 M phosphate buffer (pH 2.6)-methanol-acetonitrile (42:2:56) at a flow-rate of 1.2 ml min-1 and fluorimetric detector operating at lambda ex = 275 nm and lambda em = 336 nm is used. The retention times, under these conditions, are about 16 and 17 min for (S)-(+)- and (R)-(-)-eliprodil diastereoisomers, respectively, and about 19 min for the first-eluted diastereoisomer of the internal standard. During the analysis time, the precolumn, reset in a different path from that of the analytical column, is back-flushed with different solvents, then re-equilibrated with acetonitrile-water before the next injection. Linearity in plasma, for unchanged eliprodil enantiomers, was assessed in the range 0.15-10 ng ml-1 and for total eliprodil enantiomers (unchanged + conjugated) in the range 0.75-500 ng ml-1; the limit of quantitation (LOQ) is 0.15 ng ml-1 for each unchanged enantiomer and 0.75 ng ml-1 for each total enantiomer. Linearity was also assessed in urine for total (conjugated) eliprodil enantiomers in the range 50-25 000 ng ml-1; the LOQ is 50 ng ml-1 for each enantiomer. The intra- and inter-day precision and accuracy of the method were investigated in plasma and urine and found to be satisfactory for pharmacokinetic studies. The method has been extensively used in pharamcokinetic studies in man treated with a 20-mg dose of eliprodil racemate and some results of this application are reported.     

Column-switching liquid chromatographic method for the simultaneous determination of iothalamic acid and creatinine in biological fluids

A column-switching liquid chromatographic method for simultaneous determination of iothalamate and creatinine in human serum and urine was developed. Iothalamate and creatinine were separated on a weakly acidic ion-exchange column (C1) by ion-exclusion chromatography and iothalamate excluded from the column was purified by gel chromatography on a hydrophilic gel column (C2) and then by ion-exchange chromatography on a weakly basic ion-exchange column (C3). Creatinine that was eluted from C1 after iothalamate was transferred to a hydrophilic gel column (C4) and then to a strongly acidic ion-exchange column (C5). The mobile phase for C1-C4 was a pH 3.8 propionate buffer (propionic acid-NaOH = 0.35 + 0.035 mol/kg in water) and a pH 5.6 propionate buffer (propionic acid-NaOH = 0.04 + 0.035 mol/kg in water) was used for C5. Diluted serum and urine samples could be injected directly on to C1, as the matrix of C1 is hydrophilic and C1 is backflushed after the transfer of the creatinine fraction from C1 to C4. Iothalamate and creatinine in the eluates were determined by measuring their ultraviolet absorption at 245 and 234 nm, respectively. The precision (R.S.D.) of the chromatographic method was 1.6% (n = 7) and 0.36% (n = 6) for diluted serum and urine with iothalamate concentrations of 1.0 and 10.0 mumol/l, respectively, and 0.85% (n = 7) and 0.55% (n = 7) for diluted serum and urine with creatinine concentrations of 5.77 and 272 mumol/l, respectively.     

Exon-intron structure of the fet5+ gene of Schizosaccharomyces pombe and physical mapping of genome encompassing regions]

Groups of young male adult guinea pigs were fed a diet devoid in supplemental ascorbic acid (AA) or the same diet supplemented with 0.1 or 2.5% AA for four weeks. The animals were then euthanized and Phase I and Phase II drug metabolizing components in the liver were determined. Phase I components are those related to the metabolism of xenobiotics and include microsomal cytochrome P-450 and mixed function oxygenase activities. Phase II components are those related to conjugation and detoxification reactions of xenobiotics and their metabolites and include glutathione-S-transferases (GST), glutathione (GSH), UDP-glucuronyl transferase (UDP-GT) and DT-diaphorase (quinone reductase, QR). Tissue levels of AA increased progressively with increase in AA intake. The Phase I components increased in response to increased intake of AA from 0 to 0.1%, but were unaffected by further increase in AA intake to 2.5%. However, the Phase II components increased with increased intake of AA except for GST. In vitro metabolism of aflatoxin B1 (AFB1) using liver microsomes showed tendency towards increased production of aflatoxin M1 (AFM1) with increase in AA intake. The production of aflatoxin P1 (AFP1) was not affected by AA intake. AFB1-DNA production was increased when AA intake was increased to 0.1%. It was however lowered with further increase in AA intake to 2.5%.     

Direct gene transfer to mouse melanoma by intratumor injection of free DNA

The evaluation of commercially available test systems of competitive enzyme-linked immunosorbent assay (ELISA), for Aflatoxin M1 (AFM1) was performed in experimental conditions, through repeated analysis, in samples of milk powder contaminated with known concentrations of the toxin. Recoveries of AFM1 added to milk at levels of 0.10, 0.20, 0.50 and 1.00 ng/ml were 83.0%, 87.5%, 103.0% and 111.8% respectively. Relative standard deviations for the above mentioned concentrations were 65.5%, 31.8%, 10.9% and 13.6%, respectively (n = 10, per spiking level). According to these results the ELISA is appropriate for AFM1 research and/or surveying, mainly for concentrations between 0.20-1.00 ng/ml.     

Of sick turkeys, kwashiorkor, malaria, perinatal mortality, heroin addicts and food poisoning: research on the influence of aflatoxins on child health in the tropics

Similarities between the geographical and climatic prevalences of kwashiorkor and of exposure to dietary aflatoxins, and between the biochemical, metabolic and immunological derangements in kwashiorkor and those in animals exposed to aflatoxins, prompted investigation of the associations between kwashiorkor and aflatoxins. Studies in Africa in the 1980s indicated a role for these toxins in the pathogenesis of the disease. Paediatric cases of kwashiorkor are less prone to severe Plasmodium falciparum malaria than normal children. In mice infected with P. berghei, aflatoxin exposure inhibits parasite growth and ameliorates morbidity. Aflatoxins occur in < or = 40% of samples of breast milk from tropical Africa, usually as low concentrations of the relatively non-toxic derivatives of aflatoxin B1 (AFB1) but sometimes as high concentrations of the very toxic AFB1. This could explain kwashiorkor in breast-fed babies. Aflatoxin exposure occurs in > or = 30% of pregnancies in tropical Africa and the toxins are often in cord blood, sometimes at extremely high concentrations. Aflatoxins are now incriminated in neonatal jaundice and there is circumstantial evidence that they cause perinatal death and reduced birthweight. Aflatoxin-induced immunosuppresion may explain the aggressive behaviour of HIV infection in Africa. There are similarities between observations on HIV cases in Africa and those on heroin addicts in Europe, where 'street' heroin is frequently contaminated with aflatoxin. Aflatoxins were found in 20% of random urine samples from heroin addicts in the U.K. and the Netherlands. Aflatoxins have also been incriminated in episodes of food poisoning which have been associated with serious morbidity and mortality, particularly among young children.     

Determination of meropenem in serum by high-performance liquid chromatography with column switching

A rapid, accurate and sensitive liquid chromatographic assay with on-line solid-phase extraction for determination of meropenem in serum is described. Sample was directly injected onto the extraction column for sample clean-up and extraction. Thereafter, using an on-line column-switching system the drug was quantitatively transferred and separated on a C18 analytical column. Ultraviolet absorption at 298 nm was used for detection. The assay was linear from 1 to 100 micrograms/ml. Recovery was 98.5%. Based on a 20-microliters sample volume (serum- water, 1:1, v/v), detection limit was 0.1 microgram/ml. An application of the method to study the pharmacokinetics of meropenem is given.     

Diffusion sampling of benzene present in the urine

Benzene is a widely diffuse solvent; in the industrial environment benzene is currently present at concentrations of ppm. A valid method of biological monitoring that is easy to perform is need for assessing occupational and non-occupational exposures. A new method has been developed to evaluate low concentrations of benzene in urine samples by means of a diffusion sampling. The solvent is absorbed from the urine surface and concentrated on an absorbent substrate (Tenax) that is placed inside the vial. The solvent is thermically desorbed from Tenax and injected into a column (Thermal Tube Desorber-Supelco; 250 degrees C thermal flash; borosilicate capillary glass-column SPB-I 60 m length, 0.75 mm I.D., 1 micron film thickness; GC Dani 8580-FID). The method, which had not been previously employed for the determination of volatile organic substances in biological fluids, has a linear range which extends up to 40 micrograms/l, and gives results in excellent agreement with the conventional Head Space method, except in the low concentration region: the new method permits the quantitative determination of benzene quantities smaller than the detection limit of Head Space method connected with mass spectrometer (approximately 1 microgram/l). The detection limit was not exactly determined, but is estimated to be of 100 ng/l with 25 ml of urine sample.     

Maximum cardiac output during incremental exercise by first-pass radionuclide ventriculography

A flow injection hydride atomic absorption spectrometric (FI-HAAS) method was developed for determining selenium in human milk and whole blood after microwave digestion of the sample. The sample (2 mL human milk or 0.25 mL blood) was introduced into the microwave vessel with 1.5 mL HNO3 and 0.25 mL H2O2 and 300 W (4 min) and 600 W (4 min) were applied. The digestion was completed by heating to 140 degrees C (2-3 h). Se (VI) was reduced to Se (IV) with hydrochloric acid. The instrumental conditions for FI-HAAS (concentrations of reducing agent and carrier acid, flow rate of argon carrier gas, and sample volume injected) were optimized. The detection limit of the proposed method was 0.23 ng/mL (assay) or 115 pg Se (absolute) in biological samples (1.15 ng/mL milk, 10.4 ng/mL blood). The precision values were 5.0% for milk and 4.0% for blood. The accuracy was evaluated with 2 reference materials, National Institute of Standards and Technology Non-Fat Milk Powder (found: 104.3 +/- 7.2 ng/g, certified: 110 +/- 10 ng/g) and Whole Blood Seronorm (found: 81 +/- 7.3 ng/mL, reference: 83 +/- 4 ng/mL). The results show the suitability of the method for selenium determination in human milk and whole blood. The method was applied to whole blood samples obtained from pregnant women and to human milk.     

Aflatoxicosis in turkey poults is prevented by treatment of naturally contaminated corn with ozone generated by electrolysis

Previous studies have demonstrated that a novel source of ozone gas (O3) maybe used to chemically degrade numerous mycotoxins, including aflatoxin (AF) B1. Subsequent in vitro analyses demonstrated detoxification of AFB1, suggesting a potential method of remediate AF-contaminated grain. The objective of this study was to evaluate the capability of electrochemically produced ozone to degrade AFB1 in naturally contaminated whole kernel corn and confirm detoxification in turkey poults. Corn was procured from the southern coastal areas of Texas and HPLC revealed 1,220 +/- 73.3 ppb AFB1. Control and contaminated corn were treated for 92 h with O3 at 200 mg/min in 30 kg batches; greater than 95% reduction of AFB1 in contaminated corn was achieved. One-day-old female turkey poults were fed 1) control corn, 2) control corn + O3, 3) AFB1 corn, or 4) AFB1 corn + O3 mixed in rations (46% by wt.) and consumed ad libitum for 3 wk. When compared with controls, turkeys fed AFB1 corn had reduced body weight gain and relative liver weight, whereas turkeys fed control corn + O3 or AFB1 corn + O3 did not differ from controls. Furthermore, alterations in the majority of relative organ weight, liver discoloration, serum enzyme activity, hematological parameters, and blood chemistry caused by AFB1 were eliminated (no difference from controls) by treatment with O3. These data demonstrate that treatment of contaminated corn with electrochemically produced O3 provided protection against AFB1 in young turkey poults. It is important to note that treatment of control corn with O3 did not alter the performance of the turkey poults.