Characterization of osteoblastic properties of 7F2 and UMR-106 cultures after acclimation to reduced levels of fetal bovine serum.

Estrogen plays an important role in skeletal physiology by maintaining a remodeling balance between the activity of osteoblasts and osteoclasts. In an attempt to decipher the mechanism through which estrogen elicits its action on osteoblasts, experimentation necessitated the development of a culturing environment reduced in estrogenic compounds. The selected medium (OPTI-MEM) is enriched to sustain cultures under reduced fetal bovine serum (FBS) conditions and is devoid of the pH indicator phenol red, a suspected estrogenic agent. This protocol reduced the concentration of FBS supplementation to 0% through successive 24 h incubations with diminishing amounts of total FBS (1%, 0.1%, and 0%). The protocol does not appear to alter the viability, cell morphology, or osteoblast-like phenotype of 7F2 and UMR-106 cell lines when compared with control cells grown in various concentrations of FBS. Although the rate of mitotic divisions declined, the 7F2 and UMR-106 cultures continued to express osteoblast-specific markers and exhibited estrogen responsiveness. These experimental findings demonstrate that the culture protocol developed did not alter the osteoblast nature of the cell lines and provides a model system to study estrogen's antiresorptive role on skeletal turnover.

Factors affecting the analysis of furan in heated foods.

Various experimental factors, which could affect the measurement of furan by automated headspace gas chromatography/mass spectrometry, have been investigated. It was established that furan was not lost during sample heating through leakage or decomposition. Deuterium-labelled furan, used as an internal standard, was stable with respect to incubation in the presence of food and stable in model food systems at raised temperature. Saturation of the aqueous phase of the sample with ammonium sulphate improved the partitioning of furan from samples into the headspace. There was a very small decrease in the peak areas of both d0-furan and d4-furan when heated at acid pH. For food samples heated at normal headspace incubation temperature (50 degrees C), the level of furan was highest at the most acidic conditions used (pH 2.4) and did not differ significantly between pH 5 and 10. Under strong heating, production of furan decreased markedly at very high pH. Quantification based on standard additions or on external calibration gave comparable results for foods containing furan at relatively low, moderate and high levels.

Some factors affecting the formation of furan in heated foods.

Levels of furan in various foods were measured before and after heating under heating and laboratory conditions. The effect of contact with can coatings, sealing gaskets and the epoxidized oils used in gasket manufacture on furan formation was studied. The objective was to identify factors affecting furan formation. Furan present in heat-processed food samples persisted during cooking. Furan was shown to form in foods on heating, although it did not accumulate to a significant degree on heating in an open vessel. There were no interactions between foods and cans, can coatings or gaskets that had a significant influence on furan formation. Furan accumulated particularly in heat-processed canned and jarred foods because they are sealed containers that receive a considerable thermal load. Heating epoxidized oils used in sealing gaskets formed furan. At the levels used in gaskets, however, epoxidized oils should not affect the formation of furan in foods.

Measurement uncertainty associated with overall migration testing.

The results from a single laboratory that took part in a series of check-sample exercises for overall migration were used to calculate the measurement uncertainty for the overall migration methodology. The results span 10 years of proficiency testing and cover a range of plastic materials tested using a variety of time and temperature test conditions. Twelve sets of results for overall migration into olive oil and 10 sets of results for overall migration into volatile simulants were used. The measurement uncertainty associated with the determination of overall migration from plastics into olive oil was estimated as +/- 2.6 mg dm-2 for results between 1.2 and 15.4 mg dm-2. The measurement uncertainty associated with the determination of overall migration into volatile simulants was estimated as +/- 1.4 mg dm-2 for results between 2.1 and 13 mg dm-2. These estimates are within the analytical tolerances set in European Union regulations, of 3 and 2 mg dm-2, respectively. The performance of all laboratories participating in these 22 check sample exercises was also evaluated. A very large majority (93%) of the participants used official test methods, sometimes with minor modifications as stated. For the simulant olive oil, an average of 81% of laboratories (13 rounds with an average of 21 participants in each) using official methods was within the tolerance specified in regulations. For the volatile food simulants, an average of 87% of laboratories (11 rounds with an average of 38 participants in each) using official methods was within the tolerance specified. It is concluded from this evaluation of within- and between-laboratory data that the official European Standard methods for overall migration testing are suitable for the analysis of routine samples.

Method development and analysis of retail foods for annatto food colouring material.

Analytical methods for the determination of the permitted food colouring annatto (E160b) have been developed or refined to encompass the wide range of food commodity types permitted to contain it. Specific solvent extraction regimens have been used depending upon the food commodity analysed and HPLC analysis techniques coupled with spectral confirmation have been used for the determination of the major colouring components. Qualitative and quantitative data on the annatto content of 165 composite and two single retail food samples covering a wide range of foods at levels above the limit of quantification (0.1 mg kg(-1)) is reported. Quantitative results are given for the major colour principals 9'-cis-bixin, 9'-cis-norbixin and trans-bixin. Semi-quantitative results are given for the minor bixin and norbixin isomers monocis- (not 9'-), di-cis- and trans-norbixin, for which authentic reference standards were not available. Repeat analyses (n = 4-9) of 12 different types of food commodity (covering the permitted range) spiked with annatto at levels between 1.7 and 27.7 mg kg(-1) gave mean recoveries between 61 and 96%. The corresponding relative SDs (RSD) were between 2.1 and 7.9%.

Analysis of annatto (Bixa orellana) food coloring formulations. 2. Determination of aromatic hydrocarbon thermal degradation products by gas chromatography.

Twenty samples of commercial annatto formulations have been analyzed for m-xylene and toluene using ambient alkaline hydrolysis, followed by solvent extraction and capillary gas chromatography. Fifteen of the samples contained <5 mg/kg toluene, four samples contained between 5 and 10 mg/kg toluene, and one sample contained 12 mg/kg toluene. The amounts found of m-xylene were 200 mg/kg (one sample), 160 mg/kg (one sample), between 30 and 88 mg/kg (four samples), between 7 and 25 mg/kg (seven samples), and <5 mg/kg (seven samples). Bixin-in-oil formulations contained the highest m-xylene concentrations and also gave the largest increase in headspace m-xylene concentration when heated in closed systems. The results are evidence for the thermal degradation of annatto during source extraction and processing, resulting in contamination by internal generation of both bixin and norbixin types with aromatic hydrocarbons. Two samples of norbixin of known production history (i. e., thermal versus nonthermal processes) were analyzed specifically to identify possible differences in their degradation component profiles. They were found to differ significantly in m-xylene content, which is consistent with their respective production histories.

Oligomers in plastics packaging. Part 1: Migration tests for vinyl chloride tetramer.

Vinyl chloride (VC) tetramer has been studied as a representative oligomer that has the potential for migration from plastics packaging. Poly(vinyl chloride) (PVC) bottles for retail beverages were analysed by a process of dissolution followed by gas chromatography. Tetramer levels ranged from 70 to 190 mg/kg in the plastic. When these bottles were tested for migration into the simulants distilled water, 3% acetic acid, 15% ethanol and olive oil, no tetramer migration was detected at a limit of 5-10 micrograms/kg. Since, of the low molecular weight oligomers, the tetramer had the highest concentration in the PVC plastics, it is concluded that the other VC oligomers of higher molecular weight, would not migrate above this limit of detection either.

Migration of mineral hydrocarbons into foods. 6. Press lubricants used in food and beverage cans.

Unused food and beverage cans were supplied by manufacturers together with two typical samples of press lubricants used to facilitate stamping of can ends. The lubricants were based on mineral hydrocarbon fractions. The cans were of aluminium two-piece construction (two sizes) and tin-plate steel three-piece construction (two sizes) and of four representative types. Gas chromatographic analysis was used to distinguish the two press lubricants from one another by their n-alkane profiles. Analysis of solvent extracts of the cans indicated that one of the two press lubricants had been used in the manufacture of the three-piece cans and the other lubricant for the two-piece cans. Residual levels of hydrocarbons were between 0.05 and 1.1 mg per can. Based on the capacity of the cans and assuming all the mineral hydrocarbon transferred to the contents, maximum levels in foods and beverages could be between 0.1 and 4.4 mg/kg. A limited number of retail products were also analysed. For the 35 samples covering 18 retail brands of canned foods and beverages, press lubricants were considered to be present in 50% of the products at levels ranging from 0.05 to 1.0 mg per can, equivalent to 0.1 to 3.6 mg/kg of food. Additionally mineral oil of unknown origin was detected in 10 of the retail products at levels of 0.1 to 4.7 mg/kg. Analysis of a sparkling apple juice packed in a glass bottle showed mineral oil at 0.3 mg/kg compared with 0.7 mg/kg for the same canned product, indicating that although mineral oils may be used in can manufacture they may also be derived from other parts of the food processing chain.

Migration of styrene monomer from thermoset polyester cookware into foods during high temperature applications.

Migration of styrene from thermoset polyester cookware into foods has been studied during normal cooking applications and for the fatty food simulant olive oil under high temperature test conditions. The analysis of foods was by automated headspace gas chromatography/mass spectrometry (GC/MS) in the selected ion mode. Cyclohexane was added to the slurried foods to improve headspace partition and deuterated-styrene was the internal standard. To achieve adequate sensitivity with olive oil, styrene was extracted and concentrated by a steam distillation method and then determined by GC/MS. Styrene in foods cooked in thermoset polyester articles was in the range < 5 to 5 micrograms/kg and 5 to 30 micrograms/kg where the polyester contained 9 and 380 mg/kg residual monomer respectively. Testing for 2 h at 175 degrees C into olive oil resulted in significantly higher migration of styrene than seen for other foods, although there was a marked decrease in migration on repeat-use. Testing of the complete articles as sealed systems filled with olive oil led to higher migration than testing by total immersion of plaques. Of the test methods used with olive oil, testing as filled articles with no lidding gave migration results closest to (but generally higher than) those seen for real foods.

Migration of polyisobutylene from polyethylene/polyisobutylene films into foods during domestic and microwave oven use.

Migration of polyisobutylene from polyethylene/polyisobutylene film into foods has been studied in domestic applications such as wrapping of foods and reheating in a microwave oven. The results of these migration studies were obtained by direct measurement using newly developed analytical methods utilizing nuclear magnetic resonance (NMR) and infra-red (IR) spectroscopy as well as predictively from assessment of loss of polyisobutylene from the film. Total levels of polyisobutylene migration into cheese were found to be 8-10 mg/kg, into cake 1-5 mg/kg, and into sandwiches ranged from < 1 to 4 mg/kg. Reheating foods covered with film in the microwave oven, gave migration levels ranging from < 0.01 mg/kg for contact with steam only, up to 0.5 mg/kg for severe splashing of food onto the film and 4 mg/kg for reheated pizza. Migration of polyisobutylene was shown to be skewed towards the low molecular weight fraction of the additive. In typical films, the molecular weight range of polyisobutylene was shown to be 300-6000 daltons (95% limits) centred on 1300 daltons, whereas the additive that had migrated into cheese was found to range from 130-2200 daltons, centred on 520 daltons.

The effect of microwave energy on specific migration from food contact plastics.

Experiments have been carried out with (a) microwave treatment of plastics followed by migration testing using the food simulant, olive oil, and (b) microwave treatment of plastics in direct contact with an organic extractant (iso-octane). In neither of these complementary approaches was there evidence of any difference in migration from plastics that had been microwave-treated compared with plastics that had received an equivalent thermal treatment. Five plastics commonly employed in microwave applications were tested and oligomers, plasticizer, antioxidant and volatile contaminants were monitored as representatives of typical migration species.

An improved olive oil overall migration test for plastics using Karl Fischer titration.

Karl Fischer titration has been used to eliminate the need to humidity-condition food contact plastics under test for overall migration into olive oil. The water content of the oil is measured before and after the migration test. This direct measure of the loss (or uptake) of water by the test plastic is then used in calculations of the overall migration. The use of Karl Fischer titration gives faster analysis with reduced labour input. The time savings varied from a few days to several weeks depending on the type of plastic. Karl Fischer titration is particularly useful in the high temperature testing of polar plastics where incomplete humidity conditioning can lead to erroneous results. The technique should be equally valuable when employing sunflower oil or the triglyceride HB307 in place of olive oil.

Migration from plasticized films into foods. 5. Identification of individual species in a polymeric plasticizer and their migration into foods.

To assess the significance of migration of polymeric plasticizers into foods, chemical characterization and quantification of individual oligomeric species is required. This paper reports the identification of seven individual oligomers isolated from a poly(butylene adipate) plasticizer. Based on mass spectrometry, NMR and chemical degradation, the oligomers were identified as a series of diol-terminated units ranging from a trimer up to an 11-monomer unit, along with a cyclic tetramer, all in the molecular weight range of 300-1100. A study of the migration of polymeric plasticizer from PVC film into olive oil indicated preferential migration of low molecular weight species. These oligomers which comprised 24% of the parent plasticizer contributed more than 90% of the plasticizer migration with the smallest oligomers migrating 90-fold more readily than the bulk of the plasticizer. From a knowledge of total polymeric plasticizer migration from PVC films under actual conditions of food-use, the abundance of individual oligomers in the foods has been estimated.

Potassium loading as adjunct treatment of repetitive ventricular arrhythmias.

To evaluate potassium supplementation as adjunct therapy for ventricular arrhythmias, consecutive normokalemic patients undergoing in-hospital antiarrhythmic therapy for ventricular tachycardia were randomly assigned to one of four groups: intravenous potassium chloride (Group I, 44 patients) v intravenous saline (Group II, 48 patients); and oral potassium chloride capsules (Group III 50 patients) v no additional treatment (Group IV, 47 patients). All groups underwent serial serum potassium determinations and 24-hour electrocardiographic monitoring. Analysis revealed no significant differences in ventricular ectopic activity among groups, and there was no significant association between serum potassium level and incidence of ventricular arrhythmias. We conclude that normokalemic patients undergoing antiarrhythmic therapy for ventricular tachycardia benefit little from concomitant short-term potassium supplementation.

Migration of epoxidised soya bean oil into foods from retail packaging materials and from plasticised PVC film used in the home.

Epoxidised soya bean oil (ESBO) is used as a plasticiser and heat stabiliser in a number of feed contact materials, in particular in poly(vinyl chloride) (PVC) films and gaskets. The level of ESBO migration into foods has been determined using a combined gas chromatographic/mass spectrometric (GC/MS) analytical procedure. The study has included both the use of ESBO-containing materials for retail packaged foods and the domestic use of plasticised PVC films for applications such as wrapping food and covering food for re-heating in a microwave oven. Levels of ESBO in fresh retail meat samples wrapped in film ranged from less than 1 to 4 mg/kg, but were higher (max. 22 mg/kg) in retail cooked meat. Migration into sandwiches and rolls from 'take-away' outlets ranged from less than 1 to 27 mg/kg depending on factors such as the type of filling and the length of the contact time prior to analysis. The levels of migration of ESBO into cheese and cakes were consistent with previous experience with plasticiser migration--direct contact with fatty surfaces leading to the highest levels. When the film was used for microwave cooking in direct contact with food, levels of ESBO from 5 to 85 mg/kg were observed, whereas when the film was employed only as a splash cover for re-heating foods, ESBO levels ranged from 0.1 to 16 mg/kg. For a variety of baby foods there was no significant difference in ESBO levels between foods packaged in glass jars with PVC gaskets and foods in cans containing ESBO in the can lacquer. In both cases ESBO levels were low, ranging from less than 0.1 to 7.6 mg/kg. It is not clear for these retail samples, if the low levels observed (average 1.9 mg/kg) result solely from migration or contain some contribution from naturally occurring epoxides.

Gas chromatographic-mass spectrometric determination of epoxidized soybean oil contamination of foods by migration from plastic packaging.

A method for the quantitative determination of epoxidized soybean oil (ESBO) in foods is described. The procedure involves addition of a diepoxidized fatty acid ester internal standard, followed by lipid extraction from the food and transmethylation under basic conditions. Without further cleanup, the methylated fatty acid epoxides are derivatized to form 1,3-dioxolanes, which are then determined by capillary gas chromatography-mass spectrometry with selected ion monitoring. A detection limit of 2.0 mg/kg of epoxidized soybean oil in foods and a relative standard deviation of 7% have been achieved routinely. The method has been applied successfully to the analysis of cheeses, sandwiches, cakes, and microwave-cooked meals which have been contaminated with ESBO by migration from PVC film.

Sedation and pain management during pacemaker implantation, electrophysiologic testing, and related procedures.

A technique for the management of pain and anxiety during pacemaker implantation, electrophysiologic studies, and related procedures is described. The technique involves the intravenous administration of small amounts of the narcotic agonist-antagonist nalbuphine and the benzodiazepine diazepam. The small amounts of medication used induce relaxation while allowing the patient to interact and cooperate during the procedure. The absence of side effects facilitates outpatient treatment. This method of pain management not only improves the quality of patient care but also encourages earlier hospital discharge.