[Urinary tract infections in children. (Prolonged clinical and bacteriological control of 65 cases)].
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Adolescent↗
Biomedical subjects
A Visconti
Publications and source records attributed to A Visconti.
Assessment of intake from the diet.
Exposure assessment is one of the key parts of the risk assessment process. Only intake of toxicologically significant amounts can lead to adverse health effects even for a relatively toxic substance. In the case of chemicals in foods this is based on three major aspects: (i) how to determine quantitatively the presence of a chemical in individual foods and diets, including its fate during the processes within the food production chain; (ii) how to determine the consumption patterns of the individual foods containing the relevant chemicals; (iii) how to integrate both the likelihood of consumers eating large amounts of the given foods and of the relevant chemical being present in these foods at high levels. The techniques used for the evaluation of these three aspects have been critically reviewed in this paper to determine those areas where the current approaches provide a solid basis for assessments and those areas where improvements are needed or desirable. For those latter areas, options for improvements are being suggested, including, for example, the development of a pan-European food composition database, activities to understand better effects of processing on individual food chemicals, harmonisation of food consumption survey methods with the option of a regular pan-European survey, evaluation of probabilistic models and the development of models to assess exposure to food allergens. In all three areas, the limitations of the approaches currently used lead to uncertainties which can either cause an over- or underestimation of real intakes and thus risks. Given these imprecisions, risk assessors tend to build in additional uncertainty factors to avoid health-relevant underestimates. This is partly done by using screening methods designed to look for "worst case" situations. Such worse case assumptions lead to intake estimates that are higher than reality. These screening methods are used to screen all those chemicals with a safe intake distribution. For chemicals with a potential risk, more information is needed to allow more refined screening or even the most accurate estimation. More information and more refined methods however, require more resources. The ultimate aims are: (1) to obtain appropriate estimations for the presence and quantity of a given chemical in a food and in the diet in general; (2) to assess the consumption patterns for the foods containing these substances, including especially those parts of the population with high consumption and thus potentially high intakes; and (3) to develop and apply tools to predict reliably the likelihood of high end consumption with the presence of high levels of the relevant substances. It has thus been demonstrated that a tiered approach at all three steps can be helpful to optimise the use of the available resources: if relatively crude tools - designed to provide a "worst case" estimate - do not suggest a toxicologically significant exposure (or a relevant deficit of a particular nutrient) it may not be necessary to use more sophisticated tools. These will be needed if initially high intakes are indicated for at least parts of the population. Existing pragmatic approaches are a first crude step to model food chemical intake. It is recommended to extend, refine and validate this approach in the near future. This has to result in a cost-effective exposure assessment system to be used for existing and potential categories of chemicals. This system of knowledge (with information on sensitivities, accuracy, etc.) will guide future data collection.
Animals↗
Toxic effects of the mycotoxin zearalenone and its derivatives on in vitro maturation of bovine oocytes and 17 beta-estradiol levels in mural granulosa cell cultures.
Moulds parasites of livestock foodstuffs alter the quality of grains by synthesizing mycotoxins. Zearalenone (ZEA) and its derivatives (alpha- and beta-zearalenol, zeranol, taleranol and zearalanone) are produced by fungi of the genus Fusarium and, after ingestion via contaminated cereals, may lead to fertility disturbances and other reproductive pathologies. Zearalenone, alpha-zearalenol and zearalanone were tested, at levels ranging from 0.3 to 30 microg/ml, in order to evaluate the effect on the in vitro maturation (IVM) rate of bovine oocytes and on the formation of 17 beta-estradiol in supernatants of mural granulosa cells (GC) cultures. These compounds induced dose-dependent oocyte maturation delay and chromatin abnormalities. Maturation of oocytes to metaphase II (M II) was inhibited in oocytes cultured in the presence of 30 microg/ml ZEA, alpha-zearalenol or zearalanone, with a significant increase in chromatin abnormalities occurring in the presence of ZEA (P<0.05) and alpha-zearalenol (P< 0.001). In preliminary trials on 17 beta-estradiol formation, at the same testing concentration, higher levels of 17 beta-estradiol were found in the presence of alpha-zearalenol (mean value 1.6 ng/ml) with respect to ZEA and zearalanone (mean estradiol concentrations of 0.06 and 0.5 ng/ml, respectively). These data demonstrate a negative effect of ZEA and its derivatives on meiotic progression of bovine oocytes, possibly attributable to a toxic mechanism not related to the binding affinity of these compounds to estrogen receptor sites, and support previous observations that alpha-zearalenol acts as a stronger estrogenic inducer than the original molecule (ZEA).
Animal Testing Alternatives↗
High levels of ochratoxins A and B in moldy bread responsible for mycotoxicosis in farm animals.
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Animal Diseases↗
Natural occurrence of Alternaria mycotoxins in olives--their production and possible transfer into the oil.
A limited survey of the natural occurrence of the major Alternaria mycotoxins, i.e. alternariol (AOH), alternariol methyl ether (AME), altenuene (ALT), altertoxin-I (ATX-I), and tenuazonic acid (TA) has been carried out on olives and related processing products (oil and husks). The toxigenicity of Alternaria strains isolated from olives and the possible mycotoxin transfer into the oil have also been investigated. Four out of 13 olive samples were contaminated by 2 to 4 Alternaria mycotoxins. The highest contamination was found in a badly damaged sample containing 2.9, 2.3, 1.4 and 0.3 mg/kg of AME, AOH, ALT and TA, respectively. No mycotoxins were detected in olive-oil destined for human consumption (6 samples) or olive-husks (3 samples) collected from oil-mills after the first pressing of olives. An oil sample produced in our laboratory by processing the most contaminated olive sample contained AME (0.79 mg/kg) and AOH (0.29 mg/kg). The estimated mycotoxin amount transferred into the oil was 4% for AME, 1.8% for AOH, and zero for ALT and TA (considering 15% the oil yield). Although Alternaria species, mostly A. alternata (Fr.) Keissler, were present at various extent on all the examined olive samples, mycotoxins were only detected in samples of physically damaged olives. The production of mycotoxins by A. alternata isolated from olives was much higher (up to 3 order of magnitude for TA) on rice cultures than on olive cultures.
Alternaria↗
Stability of fumonisins (FB1 and FB2) in solution.
The stability of fumonisins B1 and B2 (FB1 and FB2) during 6 week storage was studied in acetonitrile:water (1:1) and methanol at four storage temperatures (-18, 4, 25 and 40 degrees C). Samples were analysed by HPLC with fluorescence detection after derivatization with o-phthaldialdehyde. Decomposition of fumonisins was evident in a methanol solution after 6 week storage at 4, 25 and 40 degrees C (signals for both toxins decreased by 5, 35 and 60%, respectively), whereas no losses were observed in samples stored at -18 degrees C. Both fumonisins were quite stable in acetonitrile:water solution at any of the four storage temperatures. The stability of fumonisins in acetonitrile:water (1:1) was confirmed over a period of 6 months at three temperatures (-18, 4 and 25 degrees C) in two solutions at different mass concentrations. No significant difference (t0.95-test) was observed between solutions stored in the dark at different temperatures and for different times (3 and 6 months). The overall coefficient of variation (n = 24, four measurements at each storage time and temperature) in each solution was < 3% for both toxins. Acetonitrile:water (1:1), unlike methanol, is a suitable solvent for fumonisin reference solutions.
Acetonitriles↗
Occurrence of fumonisins B1 and B2 in corn and corn-based human foodstuffs in Italy.
A survey has been carried out in Italy on the natural occurrence of fumonisins B1 (FB1) and B2 (FB2) in corn kernels from regional distributors and corn genotypes from breeding stations as well as in commercially available corn-based food products. All corn samples were fumonisin positive at levels up to 5310 ng/g for FB1 and up to 1480 for FB2. In corn-based foods, the highest fumonisin contamination levels were recorded in puffed (extruded) corn containing up to 6100 ng/g of FB1 and up to 520 ng/g of FB2. Levels ranging from 420 to 3760 ng/g FB1 and from 80 to 910 ng/g FB2 were detected in corn grits, corn flour or polenta (a sort of thick porridge made with corn flour). All sweet corn samples examined were positive for FB1, at levels varying from 60 to 790 ng/g FB1, but negative for FB2. Lower levels of fumonisins were found in other commodities, such as popcorn (up to 60 ng/g FB1 and 20 ng/g FB2), tortilla chips (up to 60 ng/g FB1 and 10 ng/g FB2), and corn flakes (10 ng/g FB1). These findings indicate a high degree of human exposure to fumonisins in Italy through the ingestion of commercially available corn-based foodstuffs.
Carcinogens, Environmental↗
Visoltricin, a novel biologically active compound produced by Fusarium tricinctum.
The major compound responsible for toxicity to Artemia salina of some Fusarium tricinctum strains has been isolated, and its structure has been elucidated by spectroscopical methods, i.e. UV, IR, MS, 1H-NMR and 13C-NMR. The novel compound, trivially named visoltricin, is the first imidazole derivative produced by Fusarium spp., and its structure has been established as the methyl ester of 3-[1-methyl-4-(3-methyl-2-butenyl)-imidazol-5yl]-2-propenoic acid (molecular formula C13H18N2O2; MW = 234.297). Visoltricin was toxic to A. salina larvae (LD50 = 8.5 x 10(-7) M), and inhibited the growth of six human tumour cell lines (out of 60 lines tested) at concentrations lower than 10(-5) M. Tested on rabbit eye it showed an interesting miotic activity similar to that of pilocarpine, a miotic agent largely used in the therapy of glaucoma. This biological activity could be explained in part by the anticholinesterase properties shown by visoltricin towards both human serum and pure enzymes (EC 3.1.1.7 and EC 3.1.1.8). Kinetics studies showed for visoltricin a mixed-type and reversible inhibition of the EC 3.1.1.7 enzyme with the competitive inhibition constant (Ki) = 1.9 x 10(-4) M.
Animals↗
European intercomparison study for the determination of the fumonisins content in two maize materials.
The results of an intercomparison study for the analysis of fumonisin B1 (FB1) and fumonisin B2 (FB2) in a contaminated maize material (Maize B, containing approximately 2 micrograms/g FB1 and 1 micrograms/g FB2) and its 'blank' counterpart (Maize A, containing less than 20 ng/g FB1 and FB2) are reported. Maize materials were distributed in 60 g sachets, submitted to gamma-irradiation at 15 kGy, and distributed to participating laboratories. The study was carried out by 24 European laboratories, most of which have national or international responsibilities for food/feed quality control. Participants used basically one method with some modifications, based on clean-up through SAX minicolumn and reversed phase HPLC with fluorescence detection of the OPA-fumonisin derivatives. The intercomparison study generated data (after correction for recoveries) with repeatability and reproducibility levels of: RSDr = 10% and RSDR = 11% for FB1; RSDr = 11% and RDSR = 13% for FB2. The recoveries obtained by most participants were considered low (70% for FB1 and 69% for FB2), being considerably affected by the extraction mode. Average recoveries for laboratories using blending were 62% and 60%, whereas for laboratories using shaking they were 85% and 86% for FB1 and FB2, respectively. The day-to-day- data showed a between-day, within-laboratory repeatability lower than 15% (CV < 15%) for FB1 for all laboratories, whereas only three laboratories obtained a between-day, within-laboratory reproducibility higher than 15% (CV > 15%) for FB2.
Animal Feed↗
Stability of fumonisins at different storage periods and temperatures in gamma-irradiated maize.
The effect of gamma-irradiation on fumonisin B1 (FB1) and fumonisin B2 (FB2) occurring in maize materials has been investigated together with the stability of fumonisins in gamma-irradiated maize stored at different temperatures (-18 to +40 degrees C) for different periods (2, 4, 13 and 26 weeks). Fifteen KGy gamma-irradiation was required to sterilize efficiently maize flour. This process caused a decrease in fumonisin content of about 20%. The stability studies showed that fumonisins are stable in gamma-irradiated maize for at least 6 months at 25 degrees C or at least 4 weeks at 40 degrees C. These data indicate that gamma-irradiation is an appropriate technique for obtaining sterilized maize materials to be used for intercomparison studies on analytical procedures for the measurement of the fumonisin content.
Carboxylic Acids↗
Determination of ochratoxin A in wine and beer by immunoaffinity column cleanup and liquid chromatographic analysis with fluorometric detection: collaborative study.
The accuracy, repeatability, and reproducibility characteristics of a liquid chromatographic method for the determination of ochratoxin A (OTA) in white wine, red wine, and beer were established in a collaborative study involving 18 laboratories in 10 countries. Blind duplicates of blank, spiked, and naturally contaminated materials at levels ranging from < or =0.01 to 3.00 ng/mL were analyzed. Wine and beer samples were diluted with a solution containing polyethylene glycol and sodium hydrogen carbonate, and the diluted samples were filtered and cleaned up on an immunoaffinity column. OTA was eluted with methanol and quantified by reversed-phase liquid chromatography with fluorometric detection. Average recoveries from white wine, red wine, and beer ranged from 88.2 to 105.4% (at spiking levels ranging from 0.1 to 2.0 ng/mL), from 84.3 to 93.1% (at spiking levels ranging from 0.2 to 3.0 ng/mL), and from 87.0 to 95.0% (at spiking levels ranging from 0.2 to 1.5 ng/mL), respectively. Relative standard deviations for within-laboratory repeatability (RSDr) ranged from 6.6 to 10.8% for white wine, from 6.5 to 10.8% for red wine, and from 4.7 to 16.5% for beer. Relative standard deviations for between-laboratories reproducibility (RSDR) ranged from 13.1 to 15.9% for white wine, from 11.9 to 13.6% for red wine, and from 15.2 to 26.1% for beer. HORRAT values were < or =0.4 for the 3 matrixes.
Beer↗
Determination of fumonisins B1 and B2 in corn and corn flakes by liquid chromatography with immunoaffinity column cleanup: collaborative study.
A liquid chromatographic (LC) method for the determination of fumonisins B1 (FB1) and B2 (FB2) in corn and corn flakes was collaboratively studied by 23 laboratories, which analyzed 5 blind duplicate pairs of each matrix to establish the accuracy, repeatability, and reproducibility characteristics of the method. Fumonisin levels in the corn ranged from <0.05 (blank) to 1.41 microg/g for FB1 and from <0.05 to 0.56 microg/g for FB2, whereas in the corn flakes they ranged from <0.05 to 1.05 microg/g for FB1 and from <0.05 to 0.46 microg/g for FB2. The method involved double extraction with acetonitrile-methanol-water (25 + 25 + 50), cleanup through an immunoaffinity column, and LC determination of the fumonisins after derivatization with o-phthaldialdehyde. Relative standard deviations for the within-laboratory repeatability (RSDr) of the corn analyses ranged from 19 to 24% for FB1 and from 19 to 27% for FB2; for the corn flakes analyses, RSDr ranged from 9 to 21 % for FB1 and from 8 to 22% for FB2. Relative standard deviations for the between-laboratories reproducibility (RSDR) of the corn analyses ranged from 22 to 28% for FB1 and from 22 to 30% for the FB2; for corn flakes analyses, RSDR ranged from 27 to 32% for FB1 and from 26 to 35% for FB2. Mean recoveries of FB1 and FB2 from corn spiked with FB1 at 0.80 microg/g and with FB2 at 0.40 microg/g were 76 and 72%, respectively; for corn flakes spiked at the same levels recoveries were 110 and 97% for FB1 and FB2, respectively. HORRAT ratios for the analyses of corn ranged from 1.44 to 1.53 for FB1 and from 0.96 to 1.48 for FB2, whereas for corn flakes they ranged from 1.60 to 1.82 for FB1 and from 1.39 to 1.68 for FB2.
Carboxylic Acids↗
[Research of the soluble microbial substances in organic fluids for the rapid diagnosis of some infections and particularly of bacterial meningitis (author's transl)].
A number of immunological and non-immunological techniques have been recently used to detect soluble microbial substances in body fluids of patients with acute meningitis, bacteremia, and lobar pneumonia. By the immunological methods capsular highly polymerized polisaccharide group- or type-specific antigens of the most common C. N. S. pathogens (N. meningitidis A, B, and C; Str. pneumoniae, H. influenzae type b, E. coli K1, mucoid Pseudomonas, Cryptococcus neoformans) can be detected and quantitated in spinal fluids, sera, urine and other fluids specimens from meningitic patients. Capsular type-specific antigens from pneumococcus, and likely from H. influenzae as well, can be detected in sputum from patients with lower respiratory infection. Among the various techniques, the radioimmunoassay appears as the most sensitive one, but high diagnostic sensitivity can be also achieved by using the latex agglutination, haemoagglutination inhibition and coagglutination tests. Counterimmunoelectrophoresis, however, is still the far most used technique for determining soluble microbial antigens, albeit its sensitivity is significantly less than the one of the above mentioned methods. High specificity and some advantages in serotyping the causal organisms are probably the main reasons of such preferential employment. Among the non-immunological techniques the evaluation of lactate and lactic dehydrogenase has been used by some Author for differentiating between bacterial and non bacterial meningitis, and the limulus test for detecting Gram-negative bacterial endotoxins with a high degree of sensitivity and specificity. Finally, the liquid gas chromatography has been evaluated in detection of some organic products (microbial?), such as acids, amines, neutral compounds, in spinal fluid, allowing the differential diagnosis between bacterial, tuberculous, viral, and cryptococcal meningitis. In the present review sensitivity, specificity, and other properties of each test alone and in comparison with the conventional microbiological methods (Gram and culture) are evaluated and the biological and pathogenic role and significance of the soluble microbial antigens and endotoxin are discussed.
Agglutination Tests↗
Mass spectrometric evidence for demethylated homologs occurring at trace levels in trichothecene standards.
Compounds with molecular weights 14 a.m.u. lower than their corresponding parent compounds have been detected in trichothecene standards during gas chromatography-mass spectrometry analysis. The positive ion chemical ionization mass spectra indicated that these compounds were trichothecene homologs lacking a methyl group on the isovaleroxy substituent at the C-8 position. Demethylated derivatives have been found in the standards of T-2, HT-2, and T-2 triol prepared in our laboratory and those obtained from a commercial source.
Dealkylation↗
[Immunological studies in experimental arthropathy in rabbits].
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Animals↗
[Clinico-epidemiological studies of maternal-neonatal colonization and infections caused by group B beta-hemolytic streptococci].
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Adult↗
[Immunofluorescence technique applied at serological diagnosis of the respiratory tract infections from gram-negatives bacteria (author's transl)].
The immunofluorescence indirect technique was evaluated for detecting specificities, Ig classes, and levels of serum and sputum antibodies against bacteria isolated from sputa in patients with broncho-pulmonary infections. Results obtained with the FA method were compared with those obtained with a passive haemagglutination test. The former method gave much more reliable results than the latter. By using FA indirect method it was possible to assess pathogenicity of baceterial strains isolated from sputum and to establish their ethiological significance in many clinical cases whose sputum cultures were impossible or difficult to evaluate, as for instance in a patient with a chronic bronchitis exacerabtion caused by a strain of Aeromonas hydrophila. Further investigation are suggested in order to improve technically the FA method and to find the easiest and most reliable way out to evaluated the effectual relationship between bacteria in sputum and immunoglobulin response in sputum or in serum of patient with respiratory tract infections due to bacteria.
Adult↗
Survey of fumonisin production by Fusarium isolated from cereals in Europe.
Strains of Fusarium isolated from corn, sorghum, wheat, barley, and mixed feed from Italy, Spain, Poland, and France were tested for the production of fumonisins B1 and B2 (FB1 and FB2) in corn cultures. All strains of F. moniliforme (1 from France, 10 from Italy, 15 from Poland, and 17 from Spain) and the one tested strain of F. proliferatum produced fumonisins in amounts scattered within a wide range of concentrations (0.7-4100 micrograms FB1/g). None or insignificant amounts of FB1 were detected in cultures of 11 F. subglutinans strains (< 0.5 microgram/g for 5 of 11 strains) or in cultures of 3 strains of Fusarium spp. not belonging to Liseola. FB2 was produced by all but one of the strains that produced FB1, and the FB2/FB1 ratio ranged from 0.1 to 0.37 (average, 0.22). The highest production of fumonisin was obtained with isolates from corn (average, 1259 micrograms FB1/g), followed by isolates from wheat (average, 769 micrograms FB1/g) and barley (average, 320 micrograms FB1/g). The production of fumonisins by isolates from sorghum was 2 orders of magnitude lower than corn. These results support data reported for similar surveys in geographical areas other than Europe. In particular, data indicate a situation in Europe that is very similar to North America in respect to fumonisin production by different Fusarium species (F. moniliforme and F. subglutinans) isolated from different substrates (corn and sorghum).
Chromatography, Liquid↗