Determination of Ochratoxin A in Green Coffee by Immunoaffinity Column Cleanup and Liquid Chomatography: Collaborative Study

A collaborative study was conducted to evaluate a method using immunoaffinity column cleanup with liquid chromatography (LC) for the determination of ochratoxin A (OTA) in green coffee at levels that could be included in possible future regulations of the European Union. The test portion was extracted with methanol–3% aqueous sodium hydrogen carbonate solution (50 + 50, v/v). The extract was filtered, and the filtrate was diluted with phosphate-buffered saline and applied to an immunoaffinity column containing antibodies specific for OTA. After washing, the toxin was eluted from the column with methanol and quantified by LC with fluorescence detection. Pairs of 4 homogeneous noncontaminated and naturally contaminated materials (mean levels of <0.12, 2.44, 5.15, and 13.46 ng/g) and blank samples (<0.12 ng/g) for spiking were sent to 20 participant laboratories from 8 countries. The materials were analyzed according to the method description and all difficulties encountered in the analysis were reported. Statistical analysis was carried out according to the Harmonized Protocol of the International Union of Pure and Applied Chemistry. The relative standard deviation for repeatability (RSDr) ranged from 7.42 to 20.94%, and the relative standard deviation for reproducibility (RSDR) ranged from 16.34 to 29.17%. The method showed acceptable within-laboratory and between-laboratories precision for green coffee materials, as evidenced by HorRat values of ≤0.85, at the studied range, for spiked and naturally contaminated materials. The mean recovery was 92.8% for green coffee material spiked with OTA at a level of 4.82 ng/g.

Immunohistochemical evidence for myofibroblast-like cells associated with liver injury induced by aflatoxin B1 in rainbow trout (Oncorhynchus mykiss)

In mammalian species, profibrogenic cells are activated to become myofibroblasts in response to liver damage. Few studies have examined hepatic myofibroblasts and their role in liver damage in teleosts. The aim of the present study was to investigate the involvement of myofibroblast-like cells in rainbow trout (Oncorhynchus mykiss) with hepatic damage induced by aflatoxin B1 (AFB1). Histopathological and immunohistochemical analyses characterized alterations in the liver stroma during the carcinogenic process. Anti-human α-smooth muscle actin (SMA) and anti-human desmin primary antibodies were used in immunohistochemistry. Only the anti-SMA reagent labelled cells in trout liver. In the livers of control fish, only smooth muscle in blood vessels and around bile ducts was labelled. In the livers from AFB1-treated fish, SMA-positive cells were present in the stroma surrounding neoplastic lesions and in areas of desmoplastic reaction. These observations indicate that in teleosts, as in mammals, the myofibroblast-like cell is involved in fibrosis associated with liver injury. Chronic liver injury induced in trout by aflatoxin may provide a useful model system for study of the evolution of such mechanisms.

Developments in mycotoxin analysis: an update for 2011-2012

This review highlights developments in mycotoxin analysis and sampling over a period between mid-2011 and mid- 2012. It covers the major mycotoxins aflatoxins, Alternaria toxins, ergot alkaloids, fumonisins, ochratoxin, patulin, trichothecenes, and zearalenone. A section on mycotoxins in botanicals and spices is also included. Methods for mycotoxin determination continue to be developed using a wide range of analytical systems ranging from rapid immunochemical-based methods to the latest advances in mass spectrometry. This review follows the format of previous reviews in this series (i.e. sections on individual mycotoxins), but due to the rapid spread and developments in the field of multimycotoxin methods by liquid chromatography-tandem mass spectrometry, a separate section has been devoted to advances in this area of research.

Developments in mycotoxin analysis: an update for 2010-2011

This review highlights developments in mycotoxin analysis and sampling over a period between mid-2010 and mid-2011. It covers the major mycotoxins: aflatoxins, Alternaria toxins, ergot alkaloids, fumonisins, ochratoxin, patulin, trichothecenes, and zearalenone. Analytical methods for mycotoxins continue to be developed and published. Despite much interest in immunochemical methods and in the rapid development of LC-MS methodology, more conventional methods, sometimes linked to novel clean-up protocols, have also been the subject of research publications over the above period. Occurrence of mycotoxins falls outside the main focus of this review; however, where relevant to analytical method development, this has been mentioned.

Developments in mycotoxin analysis: an update for 2009-2010

This review highlights developments in mycotoxin analysis and sampling over a period between mid-2009 and mid-2010. It covers the major mycotoxins aflatoxins, Alternaria toxins, ergot alkaloids, fumonisins, ochratoxin, patulin, trichothecenes, and zearalenone. New and improved methods for mycotoxins continue to be published. Immunological-based method developments continue to be of wide interest in a broad range of formats. Multimycotoxin determination by LC-MS/MS is now being targeted at the specific ranges of mycotoxins and matrices of interest or concern to the individual laboratory. Although falling outside the main emphasis of the review, some aspects of natural occurrence have been mentioned, especially if linked to novel method developments.

Developments in mycotoxin analysis: an update for 2008-2009

This review highlights developments in mycotoxin analysis and sampling over a period between mid-2008 and mid-2009. It covers the major mycotoxins: aflatoxins, alternaria toxins, cyclopiazonic acid, fumonisins, ochratoxin, patulin, trichothecenes and zearalenone. Developments in mycotoxin analysis continue, with emphasis on novel immunological methods and further description of LC-MS and LC-MS/MS, particularly as multimycotoxin applications for different ranges of mycotoxins. Although falling outside the main emphasis of the review, some aspects of natural occurrence have been mentioned, especially if linked to novel method developments.

Developments in mycotoxin analysis: an update for 2007-2008

This review highlights developments in mycotoxin analysis and sampling over a period between mid-2007 and mid-2008. It covers the major mycotoxins: aflatoxins, Alternaria toxins, cyclopiazonic acid, fumonisins, ochratoxin, patulin, trichothecenes, and zearalenone. Some aspects of natural occurrence, particularly if linked to novel aspects of analytical methods, are also included. The review demonstrates the rise of LC-MS methods, the continuing interest in developing alternative and rapid methods and the modification of well-established mycotoxin analytical methods by individual laboratories to meet their own requirements.

Effect of Fusarium verticillioides extract on specific antibody production against Paracoccidioides brasiliensis

The aim of this study was to evaluate the effect of partially purified Fusarium verticillioides fumonisins (FB) on the specific humoral response in mice infected with Paracoccidioides brasiliensis (Pb), the agent of paracoccidioidomycosis (PCM). Four groups of male Swiss mice were used (total 44 mice): infected (Pb), treated (FB), infected and treated (Pb/FB) and uninfected and untreated (PBS). Groups Pb and Pb/FB were inoculated i.v. with 1x105 Pb yeast cells (strain Pb18) and, after 28 days, groups FB and Pb/FB were inoculated (s.c.) with partially purified FB from F. verticillioides (5x2.25 mg FB/kg body weight). After 7 days, the plasma levels of total IgG and anti-gp43 IgG (specific antibody) were analysed by immunoenzyme assay (ELISA). The total IgG level was higher in groups Pb, FB and Pb/FB than in PBS (P<0.05) and the anti-gp43 IgG level was raised in groups Pb and Pb/FB, but a significant result was obtained only in Pb/FB, relative to the other groups (P<0.05). In conclusion, FB or other components of F. verticillioides extracts significantly increase the specific antibody response in male Swiss mice infected with Pb.

Implication of pre-drying steps with natural fumonisin contamination levels in freshly harvested corn

Maize quality regarding fumonisin contamination of 390 freshly harvested samples used by maize processing industries in the Northern region of Parana State, Brazil (2003 crop) was evaluated and correlated to the time elapsed from harvesting to the pre-drying step. Sampling was carried out at three points of the maize production chain, immediately after harvesting (n=100), at the industry delivery posts (n=200) and before the drying process (n=90). Fumonisin B1 (FB1) was detected in all the samples from the three points of the maize production chain. FB1 levels ranged from 0.11 to 12.68 µg/g (mean 1.81±2.12 µg/g) in the field samples, 0.10 to 11.83 µg/g (mean 1.83±1.75 µg/g) in the reception samples and from 0.02 to 10.98 µg/g (mean 2.31±2.38 µg/g) in the pre-drying samples. FB2 levels ranged from 0.01 to 5.26 µg/g (mean 0.84±0.94 µg/g) in the field samples, from 0.02 to 5.25 µg/g (mean 0.74±0.69 µg/g) in the reception samples and from 0.07 to 7.89 µg/g (mean 1.25±1.29 µg/g) in the pre-drying samples. Although there was no significant difference in mean fumonisin levels among the field, reception and pre-drying samples by the Tukey multiple comparison test (P<0.05), there was a positive correlation (P<0.05) between fumonisin levels and the time elapsed (p=0.95) from harvesting to the pre-drying step. Therefore reduction in the harvest/drying interval would be essential to assure product quality and safety and minimise potential health hazards.

Patulin biodegradation using Pichia ohmeri and Saccharomyces cerevisiae

The effectiveness of Pichia ohmeri and Saccharomyces cerevisiae in the biodegradation of patulin was evaluated in vitro. Patulin is a toxin produced by Penicillium expansum, the predominant fungal contaminant in post-harvest apple. The biodegradation experiment was carried out in culture medium (Yeast Medium broth, YM) and commercial apple juice. These substrates were artificially contaminated with patulin previously produced by P. expansum strain 2 in malt extract broth and purified over a silica gel column. The YM broth was inoculated with P. ohmeri 158 with proved anti-P. expansum activity, whereas the apple juice was inoculated with dried Saccharomyces cerevisiae cells. The residual patulin in contaminated substrates was determined by reversed-phase HPLC. P. ohmeri 158 in YM broth degraded over 83% of the initial 223 µg (8.92 µg/ml) of patulin after incubation at 25 °C for two days under static conditions; after five days of incubation, this percentage was greater than 99%, and patulin levels fell below the limit of detection after 15 days. In the apple juices inoculated with 0.25 g/l of commercial dried S. cerevisiae cells (corresponding 1.8 x 107 cells/ml), 96% of patulin was degraded (initial contamination of 4.5 µg/ml of patulin) after 143 hours of incubation at 25 °C under static conditions. However, 90% degradation occurred when the juice was contaminated with 7.0 µg/ml under the same conditions, indicating that the biodegradation rate is concentrationdependent. The effective biodegradation of patulin using P. ohmeri 158 and S. cerevisiae demonstrates a promising application for innocuous yeast isolated from natural microbiota in the biological control, which can prevent both fruit spoilage and P. expansum mycotoxin contamination.

Determination of ochratoxin A in green coffee by immunoaffinity column cleanup and liquid chomatography: collaborative study

A collaborative study was conducted to evaluate a method using immunoaffinity column cleanup with liquid chromatography (LC) for the determination of ochratoxin A (OTA) in green coffee at levels that could be included in possible future regulations of the European Union. The test portion was extracted with methanol-3% aqueous sodium hydrogen carbonate solution (50 + 50, v/v). The extract was filtered, and the filtrate was diluted with phosphate-buffered saline and applied to an immunoaffinity column containing antibodies specific for OTA. After washing, the toxin was eluted from the column with methanol and quantified by LC with fluorescence detection. Pairs of 4 homogeneous noncontaminated and naturally contaminated materials (mean levels of < 0.12, 2.44, 5.15, and 13.46 ng/g) and blank samples (< 0.12 ng/g) for spiking were sent to 20 participant laboratories from 8 countries. The materials were analyzed according to the method description and all difficulties encountered in the analysis were reported. Statistical analysis was carried out according to the Harmonized Protocol of the International Union of Pure and Applied Chemistry. The relative standard deviation for repeatability (RSDr) ranged from 7.42 to 20.94%, and the relative standard deviation for reproducibility (RSDR) ranged from 16.34 to 29.17%. The method showed acceptable within-laboratory and between-laboratories precision for green coffee materials, as evidenced by HorRat values of < or = 0.85, at the studied range, for spiked and naturally contaminated materials. The mean recovery was 92.8% for green coffee material spiked with OTA at a level of 4.82 ng/g.

Aflatoxin M1and ochratoxin A in a human milk bank in the city of São Paulo, Brazil

Because infants are more susceptible to the adverse effects of mycotoxins, this work was carried out to determine aflatoxin M(1) (AFM(1)) and ochratoxin A (OA) in milk from the Human Milk Bank of the Southern Regional Hospital, São Paulo, Brazil. Analytical methods were first established and evaluated. The methods involved the extraction of AFM(1) with methanol and OA with 1% aqueous sodium bicarbonate solution and methanol, clean-up with immunoaffinity columns having antibodies specific for each mycotoxin and quantification by high performance liquid chromatography (HPLC) with fluorescence detection. The method established for AFM(1) had mean recovery percentages of 94, 77 and 82% and coefficients of variation of 17.5, 3.4 and 4.2% at 0.01, 0.03 and 0.05 ng ml(-1), respectively. For the OA method, the corresponding values were 84, 84 and 75% for recovery and 14.1, 3.7 and 4.0% for the coefficient of variation. The limit of quantification for both methods was 0.01 ng ml(-1). Of a total of 50 samples analysed, only one was contaminated with AFM1, at 0.024 ng ml(-1), and two with OA, at 0.011 and 0.024 ng ml(-1). Although the incidence observed was low, it is recommended that the study be extended to other milk banks of the city of São Paulo.

Occurrence of aflatoxins B1, B2, G1 and G2 in cooked food components of whole meals marketed in fast food outlets of the city of São Paulo, SP, Brazil

Samples of cooked components of regular meals served at fast food outlets of the city of São Paulo, Brazil were analysed for aflatoxins B1, B2, G1 and G2. The 322 samples were composed of prepared traditional Brazilian and ethnic foods in which aflatoxins might be present. Thin-layer chromatography was used for separation of the compounds and their determination was achieved by both long wave UV light and fluorodensitometry. Aflatoxins were detected in 30 samples (9.31% of the total) in a range of 2.80 to 1323 ng/g for B1 + B2 + G1 + G2 with 90th percentiles of 158 (B1 + G1) and 258 (B1 + B2 + G1 + G2). Aflatoxin B1 was detected in all contaminated samples. The contamination levels and frequency of aflatoxins B1 and G1 in positive samples above 20 ng/g in this study are high, indicating that there is a certain degree of exposure of the population to the carcinogenic aflatoxin.

Assessment of recovery in patients undergoing intravenous conscious sedation using bispectral analysis

PURPOSE

The Bispectral Index (BIS) has been recently shown to objectively predict the level of sedation in patients undergoing conscious sedation. It was the goal of this study to directly compare the recovery profile of patients where the BIS was used to monitor sedation with a control group where the monitor was not used.

PATIENTS AND METHODS

Forty patients undergoing third molar extractions under intravenous conscious sedation were randomly assigned to 2 groups. In both groups, induction of sedation was performed using a standard dose of fentanyl (1.5 microg/kg) and midazolam (0.05 mg/kg). Propofol was then given in 10 to 20 mg boluses until a clinically desirable sedation level was achieved. In 1 group, the BIS was then monitored continually during surgery using a microcomputer (Aspect-1050 Monitor, Aspect Co, Natick, MA) and recorded at 5-minute intervals. The anesthetist (N.A.S.) provided additional propofol boluses to maintain a BIS level of 70 to 80. In the other group, the BIS sensor was applied, but the monitor was not used. In this group, the sedation was modified, and additional propofol was given based solely on the anesthetist's subjective assessment of the desired level of sedation (Observer's Assessment of Alertness/Sedation [OAA/S] scale level 2 to 3). Additional boluses of 1 mg of midazolam were given during the procedure if patients required repeated boluses of propofol at less than 5-minute intervals to maintain the desired sedation level (BIS level of 70 to 80 or OAA/S level of 2 to 3). These additional midazolam boluses, as well as the time of the last sedative dose (propofol or midazolam) were recorded to study the effect of these factors on recovery.

RESULTS

Of the 40 patients initially included in the study, 1 subject in the BIS-monitored group was excluded due to the loss of intravenous access at initiation of the case. For the remaining 39 subjects, 19 were assessed objectively using the BIS monitor, whereas 20 were assessed subjectively using the OAA/S scale. The BIS cases were slightly longer in duration than the OAA/S cases, lasting an average of 26 minutes versus 22 minutes. This difference was statistically nonsignificant (P =.19). Less propofol was used in the BIS cases, with an average of 98 mg for BIS cases versus 106 mg for OAA/S cases (P =.59). The total dose in mg/kg/min was significantly less in the BIS group (0.054 mg/kg/min) than in the OAA/S group (0.074 mg/kg/min; P =.0082). There was no significant difference in the amount of midazolam administered after induction between the 2 groups (P =.60). The surgeon, who was blinded to whether the monitor was used, ranked the third molar extractions more difficult in the BIS group (P =.05). However, patients in the BIS group were on average more cooperative, with better maintenance of muscle tone. The difference in these parameters were nonsignificant (P =.15 and .092, respectively). A positive Romberg test was obtained earlier in BIS patients, although this difference was nonsignificant (P =.097). The straight-line test was completed significantly sooner in BIS patients (P =.013). There was no significant difference between the BIS and OAA/S groups in perceptual speed (P =.55) or computation (P =.32). There was essentially no difference between groups in patient-assessed comfort or recall of the procedure. There were also no notable differences in anesthesia complications, return to activities of daily life, or pain medication use between the 2 groups.

CONCLUSIONS

The BIS provides additional information for standard monitoring techniques that helps guide the administration of sedative-hypnotic agents. It appears that use of the BIS monitor can help to titrate the level of sedation so that less drugs are used to maintain the desired level. The trend toward an earlier return of motor function in BIS-monitored patients warrants further investigation.

Technology evolution: the technology spectrum and its application to orthopedic technologies

The evolution of clinical technologies presents potential adopters with considerations in planning for clinical program development that include the stage and the rate of a technology's evolution. This paper presents a conceptual framework for these considerations and applies the framework to orthopedic technologies. Eight orthopedic surgeons were asked to assess 14 orthopedic technologies and position each of them along a spectrum of research, clinical, and adopted technologies. The distribution of responses for each technology-year combination is presented, and estimates of central tendency, dispersion, and variances provide measures of the change in the distribution of responses over time for each technology and the change in the degree of rater consensus over time for each technology. While orthopedic trauma was chosen to illustrate the technology spectrum model, the model and assessment methodology is applicable to other medical specialties as well. Adoption of this framework in a hospital setting should enable more systematic and effective clinical program development.

Childhood vitamin A status and the risk of otitis media

BACKGROUND

It has been suggested that vitamin A deficiency may predispose to otitis media.

METHODS

We conducted a prospective, observational study of 200 children, ages 3 to 5 years, on the island of Saipan in the Commonwealth of the Northern Mariana Islands. Baseline measurements of serum retinol concentrations were obtained from the children, and incidence of otitis media was determined during the following year by review of medical records. The sera were also tested for concentration of other carotenoids (beta-carotene, alpha-carotene, lutein and zeaxanthin, beta-cryptoxanthin, lycopene), and alpha-tocopherol and baseline concentrations of these compounds were also examined for relationship to incidence of otitis media.

RESULTS

Serum retinol concentrations of the children ranged from 13 to 58 microg/dl. Episodes of otitis media occurred in 22% of children during the follow-up period. Children with low serum retinol concentrations did not have an excess of episodes of otitis media (chi square for trend, 0.438; P = 0.508 for children grouped by serum retinol concentration; mean serum retinol concentrations were 29.1 and 28.6 microg/dl, respectively, for children who had and did not have a subsequent episode of otitis media). Controlling for potential confounding variables (duration of breast feeding, smoking in the household, illness or live virus vaccination in the 2 weeks before serum collection, day-care attendance) did not substantially alter this finding. Baseline serum concentrations of the other carotenoids and alpha-tocopherol also demonstrated no relation to incidence of otitis media.

CONCLUSION

In the range of serum vitamin concentrations found in this population, the status of vitamin A and related compounds in children appeared to have no effect on the incidence of otitis media.

Aflatoxins B1, M1 and aflatoxicol in tissues and urine of calves receiving aflatoxin

Liver and kidney tissues and urine from calves chronically or acutely intoxicated by aflatoxin were surveyed to detect the presence of aflatoxins B1, M1 (AFB1, AFM1) and aflatoxicol (AFL). Aflatoxins B1, M1, and aflatoxicol were not found in the liver, kidney or urine from animals intoxicated by chronic forms. However in a calf that received a single dose of 0.8 mg of AFB1/kg of live weight and one submitted to a single dose of 1.8 mg of AFB1/kg of live weight detectable levels of aflatoxins occurred in tissues and urine.

[Cardiac memory in patients with permanent artificial pacemakers]

PURPOSE

To correlate the direction of QRS complex of paced beats and postpacing T wave, in patients with artificial pacemaker.

METHODS

Thirty five patients with spontaneous rhythm obtained by chest wall stimulation or by programmability of the automatic interval. It was correlated in all patients, the direction forces of QRS complexes of paced beats and postpacing T waves in all 12 ECG leads. It was considered as a cardiac memory phenomenon when QRS complexes of paced beats and postpacing T waves had the same polarity. The phenomenon was correlated with the 12 ECG leads and with specific variables like spontaneous rhythm, QRS complex duration, type and modality of artificial stimulation and chronicity of the implant.

RESULTS

The artificial QRS complexes and spontaneous T waves had the same direction in 5 or more leads of the frontal plane in 77% of the patients and in 50% of the patients in the horizontal plane. In patients with supraventricular command, this correlation was found in 82% of the patients and in 50% of the patients with idioventricular rhythm. Regardless of the type of spontaneous command, the phenomenon was better observed with normal intraventricular conduction. It was not found correlation between type, modality of stimulation and chronicity of the implant and cardiac memory. It was better observed in aVF, D2, D3 and V3, V4.

CONCLUSION

The phenomenon of cardiac memory in patients with artificial pacemaker is very frequent. The most important factor to develop the phenomenon seem to be a normal pattern of ventricular activation.

Variations in the levels of aflatoxin in cows milk consumed in the city of São Paulo, Brazil

One hundred samples of commercially available cows milk, collected in the state of São Paulo, from July 1979 to September 1981, were analysed to determine the levels of aflatoxins M1 and M2 by the method of the AOAC. This investigation was also undertaken in 50 samples of cows milk from two farms located in the Médio Vale do Paraiba, from animals which had ingested stored feed. Aflatoxin M1 was detected in only one sample of commercially available cows milk, while those from the farms were found to contain a minimum of 0.1 microgram/l and a maximum of 1.68 microgram/l.

Natural occurrence of aflatoxins and zearalenone in maize in Brazil. Part II

The levels of aflatoxins and zearalenone were determined in 328 samples of corn from the States of Santa Catarina, Minas Gerais, São Paulo, Paraná, Rio Grande do Sul and Espírito Santo by thin-layer chromatography; the samples were obtained from April 1985 through to March 1986. In 12.3% of these samples aflatoxin B1 was detected in concentrations that varied from 10 to 900 micrograms/kg (ppb); 18 samples showed levels above those tolerated by Brazilian legislation. Zearalenone was found in 4.5% of the samples analysed in concentrations that varied from 653 to 9830 micrograms/kg (ppb). The limit of detection of the method for the determination of zearalenone was 260 micrograms/kg (ppb) and the recovery was 100%.