Soybean Oil-Derived Poly-Unsaturated Fatty Acids Enhance Liver Damage in NAFLD Induced by Dietary Cholesterol

While the impact of dietary cholesterol on the progression of atherosclerosis has probably been overestimated, increasing evidence suggests that dietary cholesterol might favor the transition from blunt steatosis to non-alcoholic steatohepatitis (NASH), especially in combination with high fat diets. It is poorly understood how cholesterol alone or in combination with other dietary lipid components contributes to the development of lipotoxicity. The current study demonstrated that liver damage caused by dietary cholesterol in mice was strongly enhanced by a high fat diet containing soybean oil-derived ω6-poly-unsaturated fatty acids (ω6-PUFA), but not by a lard-based high fat diet containing mainly saturated fatty acids. In contrast to the lard-based diet the soybean oil-based diet augmented cholesterol accumulation in hepatocytes, presumably by impairing cholesterol-eliminating pathways. The soybean oil-based diet enhanced cholesterol-induced mitochondrial damage and amplified the ensuing oxidative stress, probably by peroxidation of poly-unsaturated fatty acids. This resulted in hepatocyte death, recruitment of inflammatory cells, and fibrosis, and caused a transition from steatosis to NASH, doubling the NASH activity score. Thus, the recommendation to reduce cholesterol intake, in particular in diets rich in ω6-PUFA, although not necessary to reduce the risk of atherosclerosis, might be sensible for patients suffering from non-alcoholic fatty liver disease.

Resilience of small intestinal beneficial bacteria to the toxicity of soybean oil fatty acids

Over the past century, soybean oil (SBO) consumption in the United States increased dramatically. The main SBO fatty acid, linoleic acid (18:2), inhibits in vitro the growth of lactobacilli, beneficial members of the small intestinal microbiota. Human-associated lactobacilli have declined in prevalence in Western microbiomes, but how dietary changes may have impacted their ecology is unclear. Here, we compared the in vitro and in vivo effects of 18:2 on Lactobacillus reuteri and L. johnsonii. Directed evolution in vitro in both species led to strong 18:2 resistance with mutations in genes for lipid biosynthesis, acid stress, and the cell membrane or wall. Small-intestinal Lactobacillus populations in mice were unaffected by chronic and acute 18:2 exposure, yet harbored both 18:2- sensitive and resistant strains. This work shows that extant small intestinal lactobacilli are protected from toxic dietary components via the gut environment as well as their own capacity to evolve resistance.

Toxicity of a Soybean Oil Emulsion on Human Lymphocytes and Neutrophils

BACKGROUND

The incorporation of lipid emulsions in parenteral diets is a requirement for energy and essential fatty acid supply to critically ill patients. In this study, the toxicity of a lipid emulsion rich (60%) in triacylglycerol of omega-6 polyunsaturated fatty acids on leukocytes from healthy volunteers was investigated.

METHODS

Eleven volunteers were recruited, and blood samples were collected before infusion of a soybean oil emulsion, immediately afterwards, and 18 hours later. The cells were studied immediately after isolation and again after 24 hours or 48 hours in culture. The following determinations were made: composition and concentration of fatty acids in plasma, lymphocytes and neutrophils, lymphocyte proliferation, levels of cell viability, DNA fragmentation, phosphatidylserine externalization, mitochondrial depolarization, reactive oxygen species production, and neutral lipid accumulation.

RESULTS

Soybean oil emulsion decreased lymphocyte proliferation and provoked neutrophil and lymphocyte apoptosis and necrosis. Evidence is presented herein that soybean oil emulsion is less toxic to neutrophils than to lymphocytes. The mechanism of cell death induced by this oil emulsion was characterized by mitochondrial membrane depolarization and neutral lipid accumulation but did not alter reactive oxygen species production.

CONCLUSIONS

Soybean oil emulsion given as a single dose of 500 mL promotes lymphocyte and neutrophil death that may enhance the susceptibility of the patients to infections.

Behavior of Tamarixia triozae Females (Hymenoptera: Eulophidae) Attacking Bactericera cockerelli (Hemiptera: Triozidae) and Effects of Three Pesticides on This Parasitoid

The parasitism and host feeding behavior of Tamarixia triozae (Burks) (Hymenoptera: Eulophidae) females on Bactericera cockerelli (Sulc) (Hemiptera: Triozidae) fourth instars that have infested tomato (Lycopersicon esculentum Miller) leaflets are described and quantified. Females took approximately 31.14 ± 4.39 min to search for their first suitable host. The recognition and handling times for oviposition were 2.66 ± 0.18 and 4.26 ± 0.39 min, respectively. T. triozae parasitized 4.66 ± 0.61 nymphs in a period of 6 h. The parasitoid explored and probed its host by walking along the margins of its body while antennating and repeatedly introducing the ovipositor beneath the nymph. The handling times before and during host feeding were 8.42 ± 0.67 and 8.29 ± 0.60 min, respectively. T. triozae females consumed 1.00 ± 0.00 B. cockerelli nymph after parasitizing 3.3 ± 0.48 nymphs. EPA-a refined soybean oil-imidacloprid, and abamectin caused between ~70 and 100% T. triozae adult mortality after a 48-h contact treatment with fresh pesticide residue and a 47-91% decrease (abamectin > imidacloprid > EPA) in adult emergence when parasitized B. cockerelli fourth instars were directly sprayed. These data suggest that the use of these insecticides in combination with T. triozae in integrated pest management programs should be carefully evaluated.

Effects of bolus injection of soybean-based fat emulsion and fatty acids on pulmonary gas exchange function

To determine whether or not a "bolus injection" of soybean-based fat emulsion (SFE), which contains oleic acid (OA), a potent lung-toxic unsaturated C-18 fatty acid, can induce pulmonary dysfunction, we examined the effect of SFE injection on the partial oxygen pressure of arterial blood (Pao2) and pulmonary vascular permeability. In addition, we compared the effect of an injection of SFE with that of OA, soybean oil (a source of SFE), emulsified OA and C-18 fatty acids. Bolus injection of SFE (0.3-4.8 ml/kg) had little effect on Pao2) and pulmonary vascular permeability. Injection of an equivalent amount of OA, on the other hand, significantly decreased Pao2 and increased pulmonary vascular hyper-permeability. This decrease in Pao2 was attenuated by emulsification. Unemulsified soybean oil also induced a decrease in Pao2, although the effect was weaker than that of OA. Other unsaturated C-18 fatty acids (linoleic and linolenic acid) induced a decrease in Pao2 as potent as OA while stearic acid, a C-18 saturated fatty acid, had little effect. Although we did not observe pulmonary toxicity as a result of "bolus injection" of SFE, the chemical form, for example, emulsification and the degree of saturability of the carbon chain, seems to influence the pulmonary toxicities of lipids and fatty acids. Furthermore, the potent pulmonary toxicity of OA seems to depend not only on pulmonary vascular embolization but also pharmacological and/or inflammation-inducing properties.

Controlled Release of Methotrexate from W/O Microemulsion and Its In Vitro Antitumor Activity

The objective of this study was to prepare the microemulsion of methotrexate (M-MTX) for oral use and to investigate the suppressive effect of MTX-loaded microemulsion on MCF-7 human breast cancer cells. At the same time this effect of M-MTX was compared with those of a solution of the drug (Sol-MTX). Microemulsion was composed of soybean oil as oil phase, a mixture of Cremophore EL and Span 80 as surfactants, and isopropyl alcohol as co-surfactant, and 0.2 N NaOH as the aqueous phase. MTX was added into microemulsion at the last stage. We clearly demonstrated that M-MTX had a significant cytotoxic effect on breast cancer cell lines and the cytotoxic effect of M-MTX was significantly more than that of solutions (p < 0.05) and IC(50) value for M-MTX was 40 ng/mL. We also examined M-MTX and Sol-MTX on a model biological environmental model. For this purpose a gastrointestinal cell culture model, the Caco-2 cell line, was used to investigate the cytotoxic effects of the polymeric carrier and its effect on the cell monolayer integrity. The differences between the viability of cells for M-MTX and Sol-MTX were significantly different when applied to ANOVA according to 2 x 8 factorial randomized design (p:0.016; for alpha: 0.05, power : 0.695). According to the in vitro cytotoxicity studies, we concluded that when MTX was incorporated into the microemulsion (M-MTX), which is a new drug carrier system, it suppresses tumour cell growth on multiple tumor lines. These results indicate that M-MTX may exert a low cytotoxic effect on normal cells and may be effective as an antitumor agent that induces apoptosis.

Cytotoxicity of submicron emulsions and solid lipid nanoparticles for dermal application

The cytotoxicity and physical properties of various submicron O/W emulsions and solid lipid nanoparticles for dermal applications were investigated. Droplet size and zetapotential of submicron emulsions depended on the composition of the cosurfactant blend used. The viability of J774 macrophages, mouse 3T3 fibroblasts and HaCaT keratinocytes was significantly reduced in the presence of stearylamine. Nanoparticles consisting of stearic acid or different kinds of adeps solidus could be manufactured when formulated with lecithin, sodium taurocholate, polysorbate 80 and stearylamine. Survival of macrophages was highly affected by stearic acid and stearylamine. In general a viability of more than 90% was observed when semi-synthetic glycerides or hard fat was employed to formulate nanoparticles.

Murine strain differences in 8-hydroxy-deoxyguanosine formation in hepatic DNA induced by oxidized lard and dietary oils

Difference of 8-hydroxy-deoxyguanosine (8-OH-dG) formation in liver DNA in C3H/HeN and in C57BL/6 mice--fed oxidized lard and dietary oils (soybean and sardine)--was investigated. The blank levels of 8-OH-dG were higher in C3H/HeN mice (highly sensitive to liver tumorigenesis) than in C57BL/6 mice (resistant strain). The level of 8-OH-dG increased much more in C3H/HeN mice than in the C57BL/6 mice fed by oxidized lard and dietary oil treatment. Feeding oxidized lard and dietary oils increased 8-oxo-guanine DNA glycosylase I (OGG1) and mRNA 8-oxo-dGTPase in C57BL/6 mice. On the other hand, no appreciable change of mRNA in the C3H/HeN mice was observed. The formation differences of 8-OH-dG from the two murine strains fed with oxidized lard and dietary oils may be associated with the different mRNA levels in the DNA repair enzymes because the mRNA levels in the DNA repair enzymes were much lower in C3H/HeN mice than in C57BL/6 mice.

Genotoxicity and oxidative stress of the mutagenic compounds formed in fumes of heated soybean oil, sunflower oil and lard

This study was to investigate the genotoxicity and cytotoxicity of the oil fumes formed from heating three common commercial cooking oils (soybean oil, sunflower oil, and lard) on human lung carcinoma pulmonary type II-like epithelium cell (A-549 cell). The major alkenal mutagenic compounds (trans-trans-2,4-decadienal, t-t-2,4-DDE; trans-trans-2,4-nonadienal, t-t-2,4-NDE; trans-2-decenal, t-2-DCA and trans-2-undecenal, t-2-UDA) contained in three oil fumes and their effects on the induction of reactive oxygen species (ROS) were also studied. It was found that the most potent mutagenic compound (t-t-2,4-DDE) of oil fumes was 66.4, 35.9 and 40.3 microg/g in soybean oil, sunflower oil and lard, respectively. The results indicated that the methanolic extracts of oil fumes could apparently lead to cytotoxicity and oxidative DNA damage. Glutathione (GSH) contents and the activities of antioxidant enzymes such as GSH reductase, and GSH S-transferase were adversely reduced by the methanolic extracts of oil fumes. When human A-549 cells were exposed to the methanolic extracts of oil fumes for 30 min, there was an increase in the formation of intracellular ROS, which was determined by dichlorofluorescein assay. Moreover, the methanolic extracts of oil fumes caused significant (p<0.05) oxidative damage through the 8-hydroxy-2'-deoxyguanosine formation in A-549 cells at the concentrations from 50 to 200 microg/ml. These results demonstrated that the DNA damage in A-549 cells, induced by cooking oil fumes, was related to the ROS formation. It is inferred that women exposed to emitted fumes from cooking oil were at higher risk of contracting lung cancer.

Influence of fuel properties, nitrogen oxides, and exhaust treatment by an oxidation catalytic converter on the mutagenicity of diesel engine emissions

Particle emissions of diesel engines (DEP) content polycyclic aromatic hydrocarbons (PAH) these compounds cause a strong mutagenicity of solvent extracts of DEP. We investigated the influence of fuel properties, nitrogen oxides (NO( x )), and an oxidation catalytic converter (OCC) on the mutagenic effects of DEP. The engine was fuelled with common diesel fuel (DF), low-sulphur diesel fuel (LSDF), rapeseed oil methyl ester (RME), and soybean oil methyl ester (SME) and run at five different load modes in two series with and without installation of an OCC in the exhaust pipe. Particles from the cooled and diluted exhaust were sampled onto glass fibre filters and extracted with dichloromethane in a soxhlet apparatus. The mutagenicity of the extracts was tested using the Salmonella typhimurium/mammalian microsome assay with tester strains TA98 and TA100. Without OCC the number of revertant colonies was lower in extracts of LSDF than in extracts of DF. The lowest numbers of revertant colonies were induced by the plant oil derived fuels. In three load modes, operation with the OCC led to a reduction of the mutagenicity. However, direct mutagenic effects under heavy duty conditions (load mode A) were significantly increased for RME (TA98, TA100) and SME (TA98). A consistent but not significant increase in direct mutagenicity was observed for DF and LSDF at load mode A, and for DF at idling (load mode E) when emissions were treated with the OCC. These results raise concern over the use of oxidation catalytic converters with diesel engines. We hypothesise that the OCC increases formation of direct acting mutagens under certain conditions by the reaction of NO( x ) with PAH resulting in the formation of nitrated-PAH. Most of these compounds are powerful direct acting mutagens.

Exploration for unknown substances in rapeseed oil that shorten survival time of stroke-prone spontaneously hypertensive rats. Effects of super critical gas extraction fractions

To identify the causative substances for the shortening of survival time by rapeseed (Canola) oil in stroke-prone spontaneously hypertensive rats (SHRSP), SHRSP were fed on a standard chow supplemented with 10 w/w% soybean oil (control), rapeseed oil, one of the fractions of rapeseed oil obtained by super critical gas extraction (SCE) under a pressure of 180-bar or 350-bar, at 40 degrees C, or the residue from the extraction (with 0.5% NaCl in drinking water). In another series of experiment, SHRSP were fed for 8 weeks on the above-mentioned diets without salt loading and autopsied. Fatty acid compositions in these diets were similar, except in the soybean oil diet, and phytosterol contents were: (diet containing) 180-bar fraction>residue>rapeseed oil>350-bar fraction>soybean oil. Survival times in the rapeseed oil, 350-bar fraction and residue groups were shorter than, whereas that in the 180-bar fraction was similar to in the soybean oil group. In the 8-week feeding experiment, chronic nephropathy was found frequently in the groups other than the soybean oil group. The heart weights were higher in the rapeseed oil and residue groups. Cerebral necrosis was found in the residue group. Taken together, the followings are concluded, (1) Neither the fatty acid composition, nor the amount of phytosterols in the diets appeared to be decisive in the shortening of life. (2) SCE appeared to produce a safe (180-bar) fraction, though it failed to separate clearly the causative substances into specific fractions. (3) The factors that facilitate the genetic disease of SHRSP appear to exist in rapeseed oil. However, they might not be identical to those responsible for the life-shortening, since there were no findings common across the rapeseed oil, 350-bar and residue groups, which showed similar life-shortening.

Liver carcinogenesis and formation of 8-hydroxy-deoxyguanosine in C3H/HeN mice by oxidized dietary oils containing carcinogenic dicarbonyl compounds

Oxidized dietary oils (lard, soybean oil, and sardine oil) were orally administered to C3H/HeN male mice. After 6 months, benign hepatocellular adenoma was observed in the mice treated with all three oxidized dietary oils. After 12 months, malignant hepatocellular carcinoma and hepatoblastoma were observed in addition to the benign tumor. Oxidized sardine oil caused the highest tumor incidence (35%) and malignant tumors (27.5%) among the oxidized dietary oils tested. Mice treated with oxidized lard and sardine oil exhibited a significant increase of 8-OH-dG in the livers. The amounts of 8-OH-dG found in the mice treated with oxidized sardine oil correlated with the rates of tumor incidence. After 6 months, mRNA decreased in the case of oxidized lard and sardine oil, whereas it increased in the case of oxidized soybean oil, either in 8-oxoguanine-DNA glycosylase (OGG1) or in 8-oxo-dGTPase. On the other hand, there was no appreciable change in mRNA, in either OGG1 or 8-oxo-dGTPase, after 12 months. Oxidized sardine oil contained the highest level of malonaldehyde (MA) (713+/-91.1 nmol/g) and glyoxal (33.3+/-5.2 nmol/g) among three oxidized oils. The malignant tumor incidence correlated with the high level of MA and glyoxal found in the dietary oils tested.

Soybean oil as a possible solubilizing and vehicular medium for zinc phthalocyanine in photodynamic therapy

Soybean oil (SBO) is used as a medium to solubilize zinc phthalocyanine (ZnPc), a known photosensitizer, which has been found to be of potential use in photodynamic therapy. It absorbs red light in this medium at 670 nm with good molar absorptivity comparable to its value in most organic solvents (2.45 x 10(5) M(-1) cm(-1)). The wavelength of the fluorescence emission band peaked at 700 nm when excited at 591 nm, and when excited at 560 nm, the emission band was observed at 680 nm. The characteristic emission band of ZnPc at the near end of the visible spectral region suggests that this compound exists in this medium in a monomeric form, a form most useful in photo therapeutic applications. Moreover, the excitation wavelength, observed in the far-red region, precludes minimal effect, if any, of skin photonecrosis if this medium is used in PDT. A fluorescence spectral analysis of the ZnPc-SBO solution carried out for thirty-eight days indicates that this solution is stable within this time frame. No toxicity was detected when this solution was seeded in human endothelial cells in a culture well for 36 hr and also when injected subcutaneously into the nude and Balb C mice. In both cases the ZnPc was observed to clear from the injected area in a reasonable time. This fact coupled with its good solubilizing property for ZnPc and its virtual nontoxicity may make soybean oil a possible vehicular medium for transporting useful photosensitizers to target cells in photodynamic therapy and related applications.

Comparison of embryotoxicity of ESBO and phthalate esters using an in vitro battery system

Epoxidized soy bean oil (ESBO) and phthalate esters have been used as a plasticizer in polyvinyl chloride products. In this study, the embryotoxicity of ESBO and phthalate esters, namely, diethyl hexyl phthalate (DEHP), butylbenzyl phthalate (BBP) and dibutyl phthalate (DBP) was evaluated using short-term in vitro battery system, such as the whole embryo, midbrain and limb bud culture systems. Whole embryos at gestation day 9.5 were cultured for 48 h and the morphological scoring was measured. The cytotoxic effect and differentiation for mid-brain (MB) and limb bud (LB) cell were assessed by 50% inhibition concentration (IC(50)) with neutral red uptake and hematoxylin-stained foci (MB) or Alcian Blue staining (LB), respectively. In the whole embryo culture assay, ESBO (83, 250 and 750 microg/ml) exerted no toxic effect on growth and development of the embryo, whereas phthalate esters (1, 10, 100 microg/ml for DEHP, 10, 100, 1,000 microg/ml for BBP and DBP) inhibited growth and development dose dependently. In mid-brain and limb bud culture, the IC(50) of differentiation and cytotoxicity in BBP was 412.24 and 231. 76 microg/ml for mid-brain, and 40.13 and 182.38 microg/ml for limb bud, respectively. The IC(50) of differentiation and cytotoxicity in DBP was 27.47 and 44.53 microg/ml for mid-brain, and 21.21 and 25.54 microg/ml for limb bud cells, respectively. The lower IC(50) in both cells was obtained from DBP when compared to BBP. From these results, limb bud cells responded more sensitively to BBP and DBP than mid-brain cells. The IC(50) of limb bud cell differentiation and cytotoxicity in DBP is 1.9 and 7.1 less than that of BBP. However, any alteration in cytotoxicity and differentiation was observed with ESBO treatment. These studies suggested that ESBO is not embryotoxic; however, DEHP, BBP and DBP exhibit embryotoxic potential at high concentration.

Dietary epoxy fatty acids are absorbed in healthy women

BACKGROUND

Epoxy fats in the diet may adversely affect human health. There are no data on the absorption of these fats in humans.

METHODS

Triglycerides were synthesized containing two U-13C-labelled monoepoxy or diepoxy stearic acid molecules. Apparently healthy women consumed a standardized fatty meal (30 g fat) containing either 20 mg monoepoxy or 25 mg diepoxy fat (n = 6 and n = 7, respectively). Plasma lipid [U-13C]monoepoxy and diepoxy stearate concentrations were determined (0-24 h) by gas chromatography-mass spectrometry.

RESULTS

Plasma triglycerides increased from 1.05 +/- 0.12 to 1.83 +/- 0.13 mmol L-1 (n = 6) and from 1.10 +/- 0.19 to 1.41 +/- 0.27 mmol L-1 (n = 7) (both P < 0.001). Plasma [U-13C]monoepoxy and diepoxy stearate levels increased to 0.18 +/- 0.07 micromol L-1 (n = 6) and to 0.08 +/- 0.03 micromol L-1 (n = 7), respectively. Monoepoxy triglyceride was better absorbed than diepoxy triglyceride: 17 +/- 4 vs. 8 +/- 1% of dose (determined from area under curve (plasma 13C) normalized to that of absorbed triglycerides (plasma 12C); P < 0.02 after log transformation). The absorption of monoepoxy- and diepoxy-labelled triglycerides was related to that of normal triglycerides (r = 0.80, P < 0.05 and r = 0.91, P < 0.001, respectively).

CONCLUSIONS

Monoepoxy fats are better absorbed than diepoxy fats in women (17 +/- 4 vs. 8 +/- 1% of dose, P = 0.02). This difference in absorption is important when considering the relative toxicity of epoxidized material in the food chain.

Chronic study of diacylglycerol oil in rats

The objective of the present study was to evaluate the effects of diacylglycerol oil following long-term administration to rats. Diacylglycerol oil is an edible oil with comparable taste and physicochemical properties of several naturally occurring oils. Diacylglycerol oil can be used as a replacement for any generally used edible oil in the home and has been approved for use in cooking oil in Japan. Male and female Sprague-Dawley rats were divided into four groups and fed low-fat (1.7%) basal diets containing an edible oil composed of rapeseed, corn, high linoleic safflower and high oleic safflower oils at 5.3% (control group 1); an edible oil composed of rapeseed and soybean oils at 5.3% (control group 2); diacylglycerol oil at 2.65% plus edible oil composed of rapeseed, corn, high linoleic safflower and high oleic safflower oils at 2.65% (low-dose group); and diacylglycerol oil at 5.3% (high-dose group) for 2 years. Interim sacrifices were conducted at weeks 30 and 77 and the study was terminated following 105 weeks of feeding. No compound-related effects were noted on clinical signs, body weights, food consumption, cumulative survival rates, hematology, blood chemistry, urinalysis, organ weights or on microscopic non-neoplastic changes. Compared to control group 2, but not control group 1, there was a significant increase in the number of high-dose group females with either benign or malignant epithelial mammary gland neoplasms. These changes were not considered biologically significant, because the tumor incidence was not similar in control group 1 and 2, and the neoplastic findings were not dose related. In summary, the two-year chronic rat study revealed no toxicologically significant or treatment-related effects of diacylglycerol oil consumption at levels of up to 5.3% in the diet.

Mutagenicity of diesel exhaust particles from two fossil and two plant oil fuels

Particulate matter of diesel engine exhaust from four different fuels was studied for content of polynuclear aromatic compounds and mutagenic effects. Two so-called biodiesel fuels, rapeseed oil methylesters (RME) and soybean oil methylesters (SME), were compared directly with two fossil diesel fuels with the normal (DF) and a low sulfur content (LS-DF). Diesel exhaust particles were sampled on filters from the diluted and cooled exhaust of a test engine at five different speeds and loads. Filters were weighed for total particulate matter, Soxhlet extracted with dichloromethane and the content of insoluble material determined. The soluble organic fraction was analysed for polynuclear aromatic compounds. Mutagenicity was determined using the Salmonella typhimurium/mammalian microsome assay with strains TA98 and TA100. Compared with DF, the exhaust particles of LS-DF, RME and SME contained less insoluble material, which consisted mainly of the carbon cores of diesel exhaust particles. The concentrations of individual polynuclear aromatic compounds varied widely among the different exhaust extracts, but total concentrations of the compounds were approximately double for DF and SME compared with LS-DF and RME. In TA98 significant increases in mutation rates were obtained for the soluble organic fractions of all fuels for engines running at full speed (load modes A and D), but for DF revertants were 2- to 10-fold more frequent as compared with LS-DF, RME and SME. Revertant frequencies for DF and partly for LS-DF were also elevated in TA100, while RME and SME gave no significant increase in mutations. The results indicate that diesel exhaust particles from RME, SME and LS-DF contain less black carbon and total polynuclear aromatic compounds and are significantly less mutagenic in comparison with DF. A high sulfur content of the fuel and high engine speeds (rated power) and loads are associated with an increase in mutagenicity of diesel exhaust particles.

A novel surfactant nanoemulsion with broad-spectrum sporicidal activity against Bacillus species

Two nontoxic, antimicrobial nanoemulsions, BCTP and BCTP 401, have been developed. These emulsions are composed of detergents and oils in 80% water. BCTP diluted up to 1:1000 inactivated>90% of Bacillus anthracis spores in 4 h and was also sporicidal against three other Bacillus species. This sporicidal activity is due to disruption of the spore coat after initiation of germination without complete outgrowth. BCTP 401 diluted 1:1000 had greater activity than BCTP against Bacillus spores and had an onset of action of <30 min. Mixing BCTP or BCTP 401 with Bacillus cereus prior to subcutaneous injection in mice reduced the resulting skin lesion by 99%. Wound irrigation with BCTP 1 h after spore inoculation yielded a 98% reduction in skin lesion size, and mortality was reduced 3-fold. These nanoemulsion formulas are stable, easily dispersed, nonirritant, and nontoxic compared with other available sporicidal agents.

Nitro-polycyclic aromatic hydrocarbon contents of fumes from heated cooking oils and prevention of mutagenicity by catechin

According to earlier studies, fumes from cooking oils were found to be mutagenic and several polycyclic aromatic hydrocarbons (PAHs), (benzo(a)pyrene (B(a)P), benz(a)antracene (B(a)A), and dibenz(a,h)anthracene (DB(ah)A)) were identified. Fume samples from three different commercial cooking oils frequently used in Taiwan were collected and nitro-polycyclic aromatic hydrocarbons (NPAHs) were extracted from the samples and identified by HPLC chromatography. Extracts from three cooking oil fumes contained 1-nitropyrene (1-NP) and 1,3-dinitropyrene (1,3-DNP). Concentrations of 1-NP and 1,3-DNP were 1.1 +/- 0.1 and 0.9 +/- 0.1 micrograms/m3 in fumes from lard oil, 2.9 +/- 0.3 and 3.4 +/- 0.2 micrograms/m3 in soybean oil, 1.5 +/- 0.1 and 0.4 +/- 0.1 micrograms/m3 in peanut oil, respectively. The preventive effect of three natural antioxidants (gamma-tocopherol (TOC), lecithin (LEC), and catechin (CAT)) for the reduction of mutagenicity and amounts of PAHs and NPAHs of fumes from cooking oils were evaluated. Mutagenicity of cooking oil fumes occurred, and the concentration of B(a)P were significantly reduced (p < 0.05), by adding CAT into cooking oils before heating. B(a)A, DB(ah)A, and two NPAHs were not detected when the concentration of CAT was 500 ppm in all three cooking oil fumes. These results indicate that fumes of cooking oils contained PAHs and NPAHs that may be a risk factor for lung cancer among cooks and the carcinogens could be reduced by adding the natural antioxidant, catechin.

Carcinogenicity study of the emulsifier TOSOM and the release agent TOS in Wistar rats

Groups of 60 Wistar rats of each sex were fed diets containing 3, 6 or 12% of the margarine emulsifier TOSOM (thermally oxidized soybean oil interacted with mono- and diglycerides of fatty acids) for 2.5 yr. In addition, three groups of 60 rats of each sex were fed two products of the release agent TOS (thermally oxidized soybean oil) in dietary levels of 1.2% TOS(G) (TOS from Grindsted Product A/S, Denmark) and 0.3 and 1.2% TOS(N) (TOS from Nexus Aps, Denmark), respectively for 2.5 yr. 120 rats of each sex fed a diet containing mono- and diglycerides served as controls. The diets given to all groups were isocaloric. Clinical appearance, food consumption, body weight and weight gain, survival, haematology, and clinical chemistry parameters were examined. Gross and histopathological examinations, including neoplastic and non-neoplastic lesions, were performed on all groups. Time to occurrence of tumours was recorded. No substance-related effect, including carcinogenicity, was found.

Genotoxicity of heated cooking oil vapors

Epidemiological studies of lung cancer in Chinese women indicated that factors other than cigarette smoking are related to lung cancer risk. A case-control study suggested that indoor air pollution, particularly from cooking oil emissions, may be involved. Condensates of volatile emissions from rapeseed and soybean cooking oils were prepared and found to be genotoxic in short-term tests including the Salmonella mutation assay, SV50 forward-mutation assay, and sister-chromatid exchange assay, as well as the micronucleus assay in mouse bone marrow. In contrast, condensates from rapeseed oil with butylated hydroxyanisole or hydrogenated rapeseed oil were not mutagenic, implicating oxidation products as the cause for mutagenicity. Peanut oil and lard condensates were not mutagenic in any assay. The association of exposure to Chinese rapeseed cooking-oil emissions and lung-cancer risk may be related to the mutagenic component of these condensates.

Effect of dietary vitamin E on the toxicity of autoxidized oil to rats

Tocopherol, one of the antioxidants in vegetable fats and oils, was added to the autoxidized diet of male rats at the same tocopherol level as soybean oil before autoxidation. Autoxidized soybean oil was used as the test lipid; fresh soybean oil was the control. The diet containing autoxidized oil depressed the body weight gains and increased the tissue ratios to body weight, with the exception of testicle. Parallel with those, increased hemolysis, peroxide value and carbonyl value in the tissue lipids, and a decrease in linoleic or arachidonic acid was observed. The effect of dietary vitamin E on the tissue lipid peroxidation was different among the individual organs. From the results obtained by chemical analyses, the lipid peroxidation caused in the liver, heart and intestine was recognized to be suppressed effectively when the same tocopherol level as fresh soybean oil was added to the diet.

Lymphocyte activation, cell-mediated cytotoxicity and their relationship to dietary fat-enhanced mammary tumorigenesis in C3H/OUJ mice

The effects of dietary soybean oil (SBO) concentration (5 vs. 20% by weight) on mammary tumorigenesis, mitogen-induced blastogenesis, cell-mediated cytotoxicity and serum and lymphocyte fatty acid composition were studied in C3H/OUJ female mice. Weanling mice fed 20% SBO for 9 mo had a higher incidence (89 vs. 65%) and greater average size (2.9 vs. 1.9 g) of mammary tumor virus type S breast tumors than mice fed 5% SBO. The response of isolated splenocytes to the T-cell mitogens concanavalin A and phytohemagglutinin was 20-25% lower in mice fed 20% SBO than in mice fed 5% SBO for 20 wk. There was no effect of SBO concentration on the splenocyte response to lipopolysaccharide E55:B5, a B-cell mitogen, or to pokeweed mitogen, and B- and T-cell mitogen. Cell-mediated cytotoxicity to allogenic P815 tumor cells was 20% lower in mice fed 20% SBO than in mice fed 5% SBO for 12 wk. The lower cell-mediated immunity associated with 20% SBO was not due to changes in the fatty acid composition of the two major splenocyte membrane phospholipids, phosphatidylcholine and phosphatidylethanolamine. However, serum levels of linoleic acid were higher in mice fed 20% SBO. Raising dietary SBO from 5 to 20% by weight was associated with increased mammary tumorigenesis, reduced T-cell blastogenesis and lower cell-mediated cytotoxicity.

Lymphatics in the aorta of rats treated with a soy-bean oil extract (lipofundin)

Lipofundin-S 20% (a soy-bean oil extract) when administered intravenously to rats resulted in dilation of aortic lymphatics at the media-adventitia junction. Increased endothelial permeability as demonstrated by intraaortic colloidal iron uptake with dynamic insufficiency of lymphatic drainage is suggested as the basis for dilatation of intraaortic adventitial lymphatics.