Human exposure to bisphenol A.

Bisphenol A (BPA), 2,2-bis(4-hydroxyphenyl)propane, is made by combining acetone and phenol. It has estrogenic activity and is acutely toxic to aquatic organisms. BPA is used mainly as a material for the production of epoxy resins and polycarbonate plastics. Due to an increase in products based on epoxy resins and polycarbonate plastics, human exposure to BPA has increased. The environment (aquatic environment, air and soil) can be one source of human BPA exposure, but the primary route of human exposure is foods. The daily human intake of BPA is <1 microg/kg body weight/day on the basis of several studies, and whether these doses can have an adverse endocrine disruptive effect on humans, especially fetuses, needs to be studied carefully.

Biodegradation or metabolism of bisphenol A: from microorganisms to mammals.

Bisphenol A (BPA; 2,2-bis(4-hydroxyphenyl)propane; CAS Registry No. 80-05-7) is one of endocrine disruptors and is made by combining acetone and phenol. BPA can be metabolized by extensive organisms. In this review these BPA biodegradations or metabolisms by many organisms from microorganisms to mammals were referred. Though the metabolites of BPA can enhance estrogenicity or toxicity, generally, BPA metabolism by organisms leads to detoxication of BPA.

Bisphenol A degradation in seawater is different from that in river water.

The purpose of this study was to identify a relationship between changes of bacterial counts and bisphenol A (BPA) degradation in seawater under aerobic or anaerobic conditions, and at temperatures of 4, 25, and 35 degrees C. Water samples (seawater and river water) spiked with 1000 ng/ml of BPA was placed for 60 d. The BPA from water samples was extracted by OASIS HLB cartridges and was detected by high-performance liquid chromatography with fluorescence detection. BPA in river water was degraded under aerobic conditions and was below a detection limit (0.5 ng/ml) on the seventh day at both 25 and 35 degrees C. The more the level of bacterial counts increased, the more BPA degradation decreased. In the case of seawater samples, there was no relationship between BPA degradation and the change of bacterial counts. Bacterial counts at 25 and 35 degrees C increased rapidly at 5 and 3d, respectively, but decreased since then. The concentration of BPA was not changed for 30 d at both 25 and 35 degrees C, but decreased from 40 to 60 d in spite of low levels of bacteria. These results show that the different degradation way for BPA in seawater may exist. Moreover, our study suggest that BPA in seawater than in river water can continue for longer time with no degradation and the possibility of BPA contamination on a marine organism can be higher than that on freshwater organism.

Isolation and characterization of Campylobacter, Helicobacter, and Anaerobiospirillum strains from a puppy with bloody diarrhea.

We carried out a microscopic examination of stools from a 2-month-old female puppy with bloody diarrhea, and this revealed large numbers of different spiral-shaped bacteria. To isolate these organisms, a rectal swab specimen was inoculated onto plates of Skirrow's agar and incubated at 37 degrees C for 6 days in a microaerobic atmosphere. Finally, a total of six different spiral-shaped bacteria (strains G1104, 94105, FR106, B0101, 3J102, and J2103) were isolated. Based on their morphology, biochemical traits, whole-cell protein profiles, and analysis of their 16S rDNA sequences, they were identified as Campylobacter upsaliensis, Helicobacter cinaedi, 'Flexispira rappini', two Anaerobiospirillum spp. with different morphologies, and Helicobacter sp., respectively. Analysis of 16S rRNA gene sequence data for strains 94150 (H. cinaedi) and FR106 (F. rappini) revealed that this approach has limitations when identifying isolates to the species level because of a high degree of sequence homology between these species (>99%) and considerable sequence variation among different isolates within these species. The dog was treated orally with amoxicillin for 3 days, which resolved the diarrhea. However, 1 day after the last dose the bloody diarrhea recurred but regarded to six more days amoxicillin treatment. This suggests a bacterial cause for the diarrhea. The approach to identification to microaerobic spiral-shaped bacteria in diarrheic dogs can be applied further to characterize their role in diarrhea illness.

Determination of bisphenol A in milk and dairy products by high-performance liquid chromatography with fluorescence detection.

This study was conducted to develop a selective and sensitive method for the determination of bisphenol A (BPA) levels in milk and dairy products. A method based on solvent extraction with acetonitrile and solid-phase extraction (SPE) was developed for the analysis of BPA in milk, yogurt, cream, butter, pudding, condensed milk, and flavored milk, and a method using two SPE cartridges (OASIS HLB and Florisil cartridge) for skim milk was also developed. The developed methods showed good recovery levels (77 to 102%) together with low detection limits (1 microg/liter for milk, yogurt, pudding, condensed milk, flavored milk, and skim milk and 3 microg/liter for cream and butter). These methods are simple, sensitive, and suitable for the analysis of BPA in milk and dairy products. When 40 milk and dairy products were analyzed by the proposed methods, BPA was not identified in noncanned products, but its levels ranged from 21 to 43 microg/kg in canned products, levels that were 60- to 140-fold lower than the migration limits in the European Union and Japan.

Factors influencing the migration of bisphenol A from cans.

The objective of this study was to determine whether there is a relationship between bisphenol A (BPA) migration from metal cans and container contents (glucose, sodium chloride, and vegetable oil), heating time, and/or temperature. Cans containing 5 to 20% glucose solution, 1 to 10% sodium chloride solution, and vegetable oils (corn, olive, and soybean oil) were heated at 121 degrees C for 30 min. Water samples were heated at 105 degrees C for 30 min and at 121 degrees C for 15, 30, and 60 min, respectively. In the test involving water samples, it was found that temperature's effect on BPA migration from cans can be more extensive than that of heating time. When cans were heated at 121 degrees C, the presence of 1 to 10% sodium chloride or vegetable oils greatly increased the migration of BPA from the cans. Moreover, the presence of 5 to 20% glucose in cans heated to 121 degrees C resulted in increased BPA migration relative to that for water controls.

Effects of bacterial counts and temperature on the biodegradation of bisphenol A in river water.

Total 15 surface river waters were collected from thirteen different rivers to investigate a relationship of bacterial counts and temperature to the degradation of bisphenol A (BPA). Autoclaved and non-autoclaved river water samples were spiked with 0.2 mg/l BPA. The spiked samples were placed at temperatures of 4, 20, and 30 degrees C and analyzed by high performance liquid chromatography. BPA was degraded at all temperatures in the non-autoclaved samples. However, BPA in the autoclaved samples was not changed at all temperatures for 20 d. These results show that the primary factor of BPA degradation in river water is bacteria. Moreover, three groups [group A (> 10000 CFU/ml), group B (2000-10000 CFU/ml), and group C (< 2000 CFU/ml)], were made on the basis of bacterial counts of the samples. Half-lives for BPA degradation in groups A, B, and C were 2, 3, and 6 d at 30 degrees C and were 4, 5, and 7 d at 20 degrees C, respectively. But at 4 degrees C, the loss of BPA was about 40%, 20%, and 10% in groups A, B, and C for 20 d, respectively. Bacterial counts exerted an influence on BPA degradation in river water with temperature. Our results also show that BPA-degrading bacteria are widely distributed in river waters.

Determination of bisphenol A in canned pet foods.

Bisphenol A (BPA) contamination of canned foods for human use has been studied, but there are no reports concerning BPA contamination of canned pet foods. The purpose of this study was to identify the levels of BPA in canned pet foods. A total of 26 samples (15 samples of cat food and 11 samples of dog food) were prepared for analysis by high-performance liquid chromatography. BPA in the samples was extracted with acetonitrile and fat in the sample extract was removed with hexane. Solid-phase extraction was used for sample clean-up prior to final analysis. The concentration of BPA ranged from 13 to 136 ng/g in canned cat food and from 11 to 206 ng/g in dog food. Also, to confirm that the BPA had originated from the can coating, distilled water was added to each washed empty can and the cans were autoclaved at 121 degrees C for 30 min. The concentration of BPA leached from empty cans was between 7 and 31 ng/ml.

A Simple Method for the Characteristic Differentiation of Antibiotics by TLC-Bioautography in Graded Concentration of Ammonium Chloride.

A simple classification method for 24 known antibiotics by TLC-bioautographic procedure was developed. The approach used was to change the Rf values in seven TLC systems with an ammonium chloride solution in a graded concentration range (0.5, 1, 2, 3, 5, 10 and 20%). The antibiotics were divided into four groups (A to D) showing the characteristic behavior of Rf values corresponding to similarities in chemical structure: ß-lactam, aminoglycoside, macrolide and tetracycline antibiotics. TLC-bioautography helps to estimate the character of antibiotics and the characteristic change of Rf values may be very useful for classifying unknown residual antibiotics in animal samples as a routine laboratory test.

Improved Method for the Determination of Residual Aminoglycoside Antibiotics in Animal Tissues by Electrophoresis and Bioautography.

The use of agar gel electrophoresis and bioautography for the identification of small amounts of seven aminoglycoside antibiotics (streptomycin, dihydrostreptomycin, kanamycin, bekanamycin, gentamicin, fradiomycin and paromomycin) was studied. The procedure used for the electrophoretic separation of these components is described. The antibiotics were detected with high sensitivity using Bacillus subtilis ATCC 6633 as a test organism, Tris buffer at pH 8.0, and Bacto-Agar as the supporting medium for each of the components. The limits of detection obtained for the various antibiotics ranged between 0.078 and 0.313 µg/ml and the standard deviation ranged from 0.05 and 0.34. Recoveries from extracts of bovine kidney tissue containing each drug ranged from 59.0% to 90.2%. The sensitivity of this method can be adjusted through minor modifications, thus allowing it to be used for routine residual analysis of aminoglycosides in biological samples.

Gas-Liquid Chromatographic Determination of Propionic Acid Production Differentiates between the Food-Poisoning Strains and Toxigenic-Type Strains of Clostridium perfringens.

Fatty acids of 32 strains belonging to five types of Clostridium perfringens were extracted from the supernatant liquid of cultures in various different media prepared with or without the addition of sugar and examined by application of the gas-liquid chromatographic technique. The major products in nearly all media were acetic, propionic and butyric acid among the volatile fatty acids and only lactic acid among the nonvolatile fatty acids. Quantitative comparison of the resulting chromatograms with regard to the presence and relative amounts of propionic acid as one of the large major peaks revealed clear differences between the toxigenic types and the food-poisoning strains of this organism. In cooked meat medium containing 2% fructose, all the toxigenic-type strains produced propionic acid, but the food-poisoning strains tested entirely lacked production of this acid. This differentiation characteristic may be useful in routine laboratory bacteriology.

Simultaneous Determination of Six Tetracyclines in Bovine Tissue, Plasma and Urine by Reverse-Phase High-Performance Liquid Chromatography.

A simple and rapid high-performance liquid chromatographic method was developed for the simultaneous separation and identification of six different tetracycline antibiotics (minocycline, oxytetracycline, tetracycline, dimethylchlortetracycline, chlortetracycline, and methacycline) in bovine kidney, plasma and urine. The antibiotics were separated at ambient temperature on a µ-Bondapak C18 column using a mobile phase [water 760 ml, acetonitrile 240 ml, N,N'-dimethylfolmamine 60 ml, ethanolamine 5.0 ml and Na2HPO4 5.2 g, pH 2.5] at a flow rate of 1.5 ml/min. A variable-wavelength detector set at 254 nm, 0.05 AUFS and a recorder set at 4mm/min were used for the detection. The entire mixture was resolved in less than 12 min by this method. The limits of detection for the tetracyclines ranged from 1.25 to 0.125 µg/ml. Recoveries of tetracyclines from biological samples were 72.3 - 80.6% kidney, 78.2 - 83.7% in plasma and 80.2 - 88.4% in urine, respectively. The method was sensitive, reproducible, and applicable to the quantitative analysis of tetracyclines in biological samples.

Bisphenol A migration from cans containing coffee and caffeine.

This study was conducted to reconfirm the possibility and level of bisphenol A (BPA) migration from cans containing coffee and test the relationship between caffeine concentration and BPA migration from the can coating. BPA migration from cans containing decaffeinated and non-decaffeinated instant coffee averaged 66.2 and 84.0 ng ml(-1), respectively. In our study, the possibility of BPA migration from cans containing coffee after processing was found. In addition, the more caffeine content in the water solution of caffeine increased, the more BPA migration grew. This means that caffeine can have an effect on BPA migration from the can coating.

Simultaneous Determination and Identification of Penicillin Residues by High-Performance Liquid Chromatographic Analysis.

A new method was developed for simultaneous determination and identification of seven penicillins (amoxicillin, ampicillin, methicillin, penicillin G, oxacillin, cloxacillin, and dicloxacillin) in bovine serum. Each sample was simply extracted with acetonitrile, and identification of the reaction products of penicillins after treatment with 1,2,4-triazole-HgCl2 solution was then carried out by high-performance liquid chromatography (HPLC) with on ultraviolet spectrophotometric detector at 325 nm. Separation of the penicillin reaction products by HPLC was carried out by using a mobile phase of 0.1 M phosphate buffer and acetonitrile in ratios of 85:15 and 60:40 (vol/vol) in a gradient flow. The retention times of the seven penicillins ranged from 4.3 to 24.6 min, and the detection limits of penicillin concentration ranged from 0.04 to 0.2 µg/ml. The calibration curves for individual penicillins extracted from bovine serum were linear, and the correlation coefficients for each of the drugs were over 0.99. The determination of penicillins extracted from bovine serum spiked with each drug gave a recovery rate from 82.0 ± 5.6% to 105.6 ± 4.6%. This detection method may be useful for routine laboratory testing of residual penicillins.

Simple Continuous and Simultaneous Determination of Multiple Sulfonamide Residues.

A new continuous separation method was developed for the determination of nine different sulfonamides (sulfaguanidine, sulfamethazine, sulfapyridine, sulfadiazine, sulfathiazole, sulfamethizole, sulfamethoxazole, sulfadimethoxine, and sulfaquinoxaline). Bioassay on minimum medium seeded with Bacillus subtilis ATCC 6633 was carried out for detection. An extract taken from an agar block of the clear inhibition zone on minimum medium produced by a mixture of sulfonamides was then subjected to high-performance liquid chromatography. For identification, high-performance liquid chromatography analyses were performed using two different columns and analytical conditions. Using a µ-Bondapak C18 column, the sulfonamides were separated at room temperature using a mobile phase of methanol: 0.1 M KH2PO4 (30:70, vol/vol) at a flow rate of 1.0 ml/min. A variable wavelength detector set at 265 nm and recorder set at 4 mm/min were used for the detection. The entire mixture was resolved as eight peaks from 4.68 to 50.78 min. When an Asahipak GS-320 column was employed, nine peaks were separated with retention times ranging from 12.62 to 54.43 min using a mobile phase of acetonitrile: 1% acetic acid (25:75, vol/vol) at a flow rate of 2.0 ml/min. Correlation coefficients of standard curves for individual sulfonamides were linear (>0.99) with recoveries ranging from 25.2 ± 8.6% to 64.1 ± 8.6% for a concentration range of 1.0-25 µg/ml.

Simple and Rapid Method for Determination of Oxolinic Acid in Tiger Shrimp ( Penaeus monodon ) by High-Performance Liquid Chromatography.

A simple high-performance liquid chromatographic method for determining oxolinic acid in tiger shrimp ( Penaeus monodon ) tissue has been developed. The sample was simply extracted with ethyl acetate without further clean-up. The extract was analyzed using reversed-phase chromatography with UV detection at 330 nm. An extraction efficiency of 97.4 ± 10.3% was obtained. The within-run precision ranged from 1.46 to 4.21% and the between-run precision ranged from 6.01 to 9.77%. Detection of oxolinic acid in spiked shrimp was linear from 0.007 to 4 µg/g with a correlation coefficient of 0.998. The minimal detection limit of this procedure was 0.0035 µg/g.