Identifying alternative solvents for C60 manufacturing using singular and combined toxicity assessments.

Linseed oil, olive oil, and sunflower oil were selected based on green chemistry principles and C60 solubility as alternative solvents to replace 1,2,4-trimethylbenzene (TMB) for C60 manufacturing. Singular acute toxicity experiments of C60 and the four solvents was performed using Daphnia magna to identify the solvent with the lowest toxicity and estimate the toxicity of C60. The EC50 for C60 was estimated to be higher than 176 ppm. The toxicity of the solvents increased from sunflower oil to olive oil, linseed oil, and TMB. Combined toxicity tests were conducted to investigate the interaction between C60 and the solvent since essential oils can be nanocarriers and facilitate the transport of C60 into the cell membranes, which would increase its toxicity. Various concentrations of C60 (0, 11, 22, 44, 88, and 176 mg/L) were mixed with solvents at their EC50 concentrations. The toxicity of linseed oil increased with increasing C60 concentrations. For olive and sunflower oil, the toxicity was lowered with low concentrations of C60. Olive oil was determined to be a suitable solvent for C60 manufacturing based on singular and combined toxicity assessments. This study showed the importance of considering combined toxicity for solvent selection.

From pure compounds to complex exposure: Effects of dietary cadmium and lignans on estrogen, epidermal growth factor receptor, and mitogen activated protein kinase signaling in vivo.

Exposure to environmental endocrine active compounds correlates with altered susceptibility to disease in human populations. Chemical risk assessment is single compound based, although exposure often takes place as heterogeneous mixtures of man-made and natural substances within complex matrices like diet. Here we studied whether the effects of cadmium and enterolactone on endocrine endpoints in dietary exposure can be predicted based on pure compound effects. Ovariectomized estrogen reporter ERE-luciferase (ERE-luc) mice were maintained on diets that intrinsically contain increasing concentrations of cadmium and enterolactone precursors for three and 21 days. The activation of the ERE-luc, epidermal growth factor receptor (EGFR), mitogen activated protein kinase (MAPK)-ERK1/2, and classical estrogen responses were measured. Interactions between the diets and endogenous hormone were evaluated by challenging the animals with 17ß-estradiol. Compared to animals on basal purified diet, mice consuming experimental diets were exposed to significantly higher levels of cadmium and enterolactone, yet the exposure remained comparable to typical human dietary intake. Surprisingly, we could not detect effects on endpoints regulated by pure enterolactone, such as ERE-luc activation. However, cadmium accumulation in the liver was accompanied with activation of EGFR and MAPK-ERK1/2 in line with our earlier CdCl2 studies. Further, attenuation of 17ß-estradiol-induced ERE-luc response in liver by experimental diets was observed. Our findings indicate that the exposure context can have substantial effects on the activity of endocrine active compounds in vivo. Thus, whenever possible, a context that mimics human exposure should be tested along with pure compounds.

Dietary flaxseed intake exacerbates acute colonic mucosal injury and inflammation induced by dextran sodium sulfate.

Flaxseed (FS), a dietary oilseed, contains a variety of anti-inflammatory bioactives, including fermentable fiber, phenolic compounds (lignans), and the n-3 polyunsaturated fatty acid (PUFA) α-linolenic acid. The objective of this study was to determine the effects of FS and its n-3 PUFA-rich kernel or lignan- and soluble fiber-rich hull on colitis severity in a mouse model of acute colonic inflammation. C57BL/6 male mice were fed a basal diet (negative control) or a basal diet supplemented with 10% FS, 6% kernel, or 4% hull for 3 wk prior to and during colitis induction via 5 days of 2% (wt/vol) dextran sodium sulfate (DSS) in their drinking water (n = 12/group). An increase in anti-inflammatory metabolites (hepatic n-3 PUFAs, serum mammalian lignans, and cecal short-chain fatty acids) was associated with consumption of all FS-based diets, but not with anti-inflammatory effects in DSS-exposed mice. Dietary FS exacerbated DSS-induced acute colitis, as indicated by a heightened disease activity index and an increase in colonic injury and inflammatory biomarkers [histological damage, apoptosis, myeloperoxidase, inflammatory cytokines (IL-6 and IL-1ß), and NF-κB signaling-related genes (Nfkb1, Ccl5, Bcl2a1a, Egfr, Relb, Birc3, and Atf1)]. Additionally, the adverse effect of the FS diet was extended systemically, as serum cytokines (IL-6, IFNγ, and IL-1ß) and hepatic cholesterol levels were increased. The adverse effects of FS were not associated with alterations in fecal microbial load or systemic bacterial translocation (endotoxemia). Collectively, this study demonstrates that although consumption of a 10% FS diet enhanced the levels of n-3 PUFAs, short-chain polyunsaturated fatty acids, and lignans in mice, it exacerbated DSS-induced colonic injury and inflammation.

A comprehensive evaluation of the toxicology of experimental cigarettes manufactured with banded papers.

CONTEXT: To comply with state requirements, cigarette manufacturers have added low-permeability bands to the cigarette paper. These bands can extinguish the cigarette when it is no longer being puffed by a smoker. OBJECTIVE: This study was conducted to evaluate the toxicology resulting from the addition of different types of bands to experimental cigarettes. MATERIALS AND METHODS: A battery of assays that are typically used in toxicology studies with cigarette smoke, namely smoke chemistry, in vitro mutagenicity and cytotoxicity, and inhalation studies with rats, were used to evaluate different band characteristics added to cigarette paper. RESULTS: Although differences in the amount of band material was associated with an increase in some metals measured in mainstream tobacco smoke, it was not dose responsive to any band design parameter (base paper permeability, band width, band spacing, band chalk amount, or citrate). Occasional, minor differences were produced by the different types of bands; overall, there was no increased toxicity. CONCLUSION: Although there were increases and decreases in some mainstream smoke constituents, the in vitro and in vivo testing performed demonstrated that low-permeability bands on cigarettes do not modify the toxicity of smoke inhaled by smokers.

A comprehensive evaluation of the toxicology resulting from laser-generated ventilation holes in cigarette filters.

CONTEXT: Recent technological advances allow ventilation holes in (or adjacent to) cigarette filters to be produced using lasers instead of using the mechanical procedures of earlier techniques. OBJECTIVE: Analytical chemistry can be used to compare the composition of mainstream smoke from experimental cigarettes having filters with mechanically produced ventilation holes to that of cigarettes with ventilation holes that were produced using laser technology. MATERIALS AND METHODS: Established procedures were used to analyze the smoke composition of 38 constituents of mainstream smoke generated using standard conditions. RESULTS: There were no differences between the smoke composition of cigarettes with filter ventilation holes that were produced mechanically or through use of laser technology. CONCLUSION: The two methods for producing ventilation holes in cigarette filters are equivalent in terms of resulting mainstream smoke chemistry, at two quite different filter ventilation percentages.

A comprehensive evaluation of the toxicology of experimental, non-filtered cigarettes manufactured with different circumferences.

CONTEXT: Historical work indicates that cigarette circumference may affect the toxicological profile of experimental cigarettes. OBJECTIVE: Studies were conducted to examine the effect of different cigarette circumferences on (1) selected mainstream smoke constituents including concentrations of tobacco specific nitrosamines (TSNA) in smoke and (2) mutagenicity and cytotoxicity of cigarette smoke condensate. MATERIALS AND METHODS: Analytical chemistry, Salmonella mutagenicity and cytotoxicity assays were used to evaluate the composition and biological activity of mainstream smoke from experimental, non-filtered cigarettes manufactured with four different circumferences (17.0-27.1 mm). RESULTS: Most smoke constituents, including TSNA, decreased with decreasing cigarette circumference; however, amounts of hydrogen cyanide increased in a non-circumference dependent manner. Mutagenicity and cytotoxicity also decreased slightly with decreasing cigarette circumference. CONCLUSION: Cigarette circumference may have a minor role in the toxicological profile of experimental cigarettes, with a so-far-unidentified mechanism.

Cancer incidence among women flax textile manufacturing workers in Lithuania.

OBJECTIVE: To determine site-specific cancer incidence among women spinning-weaving and dyeing-finishing workers in the largest flax textile factory in Lithuania. METHOD: The cancer incidence of a cohort of 3447 women workers from a flax textile factory was investigated for the period 1978-2002. All subjects were employed at the plant in the period 1957-2000 for a minimum of 12 months. Standardised incidence ratios (SIRs) were estimated by use of the corresponding national rates. SIRs were calculated for the spinning-weaving and dyeing-finishing work categories, and for two durations of employment categories (<10 years, > or =10 years). RESULTS: The cancer SIRs among spinning-weaving and dyeing-finishing workers were 0.84 (95% CI 0.69 to 1.00) and 0.90 (95% CI 0.52 to 1.44). An incidence deficit for non-melanoma skin cancer was found for the spinning-weaving unit (SIR 0.45, 95% CI 0.18 to 0.92). The risk of oral cavity and pharynx cancer was significantly increased in spinning-weaving unit workers with <10 years of employment (SIR 5.71, 95% CI 1.56 to 14.60). A significant excess of thyroid cancer and nervous system cancer was found among dyeing-finishing workers. CONCLUSIONS: The overall cancer and non-melanoma skin cancer incidence rate among flax spinning-weaving workers was lower compared with the Lithuanian population. The present findings lend some support to an excess of thyroid and nervous system cancers among dyeing-finishing workers and of oral cavity and pharynx cancer in spinning-weaving workers.

The effects of dietary flaxseed on the Fischer 344 rat: I. Development, behaviour, toxicity and the activity of liver gamma-glutamyltranspeptidase.

The effect of exposure to, followed by consumption of, 10% flax chow from the 18th day of gestation to the 86th day after birth was examined in male and female Fischer 344 rats. Growth curves of the flax chow-fed rats were identical to those of regular chow-fed rats, as were such developmental milestones as pinna development, growth of hair and eye opening. Acoustical startle and the righting reflexes, developmental behavioural indices, were also the same. Blood glucose levels were comparable in flax chow-fed and regular chow-fed rats at all stages of development, indicating that flax is without effect on glucose balance. There were no signs of toxicity in the flax chow-fed rats since their plasma levels of alanine aminotransferase and gamma-glutamyltranspeptidase (gammaGT) were the same as those of regular chow-fed rats. The activity of gammaGT displayed an increase in the livers of flax chow-fed rats after puberty, more so in the male-four-fold-than in the female-1.38-fold. This is suggestive of an estrogenic effect which implicates an effect of an estrogenic flax lignan. An hepatobeneficial effect of the flax-induced increase in liver gammaGT is discussed. In summary, dietary 10% flax chow is without long-term effect on growth, development and behaviour, is non-toxic and may be hepatoprotective.

Effects of flaxseed and defatted flaxseed meal on reproduction and development in rats.

Flaxseed, a rich source of reportedly beneficial n-3 fatty acid and phytoestrogens, has not been thoroughly tested for reproductive effects. High levels of flaxseed (FS, 20 or 40%) or defatted flaxseed meal (FLM, 13 or 26%) added to AIN-93 diet were evaluated in a two-phase study: dosed during gestation only or during gestation and maturation in a lifetime study. At cesarean section on gestation day 20, neither FS nor FLM affected fertility, body weight gain, litter size, or fetal development. FLM, but not FS, decreased gestation length. The offspring of dams allowed to litter were observed to postnatal day (PND) 21 or 90. Neither FS nor FLM affected PND 21 survival indices of F1 pups. FS (20 and 40%), but not FLM, increased the anogenital index (AGI) of F1 females at PND 21. The AGI of F1 males was not affected by either FS or FLM. FLM (13 and 26%), but not FS, delayed puberty in F1 males. Age and weight at the onset of puberty in females were not affected by FS or FLM. FS and FLM caused dose-related increases in the number of F1 females with irregular estrous cycles. During PND 21-90, F1 females fed 20% FS, 13% FLM, or 26% FLM gained more weight than the controls. FS and FLM decreased thymus/body weight and thymus/brain weight ratios in weanling F1 males and females. FS and FLM decreased liver/body weight and liver/brain weight ratios in weanling F1 females, and 26% FLM decreased the same two ratios in F1 males. In conclusion, FS did not affect fetal development but did affect indices of postnatal development such as the estrous cycle.

Developmental effects of serum from flaxseed-fed rats on cultured rat embryos.

Gestation day 9.5 rat embryos were cultured for 45 h in serum obtained from pregnant rats that had been fed throughout gestation with either a control diet (based on the AIN-93 formulation), a diet supplemented with flaxseed (20% or 40%, w/w), or a diet supplemented with de-fatted flaxseed ("flaxseed meal", 13 or 26%, w/w). The embryos were fixed in neutral formalin at the end of culture. Overall growth and development was assessed, and the presence of abnormalities was noted. A significant inhibition of growth (as determined by crown-rump length) relative to control was observed in embryos cultured in serum from rats fed the 20% flaxseed diet. The incidence of spontaneous heart inversions was increased significantly in the embryos cultured in serum from the 20% flaxseed and 26% flaxseed meal fed rats. The incidence of flexion defects was increased significantly in embryos cultured in serum from 20% flaxseed-fed rats. The lack of an apparent dose response in any of the statistically significant effects suggests that the observed anomalies were chance occurrences unrelated to the treatment group from which serum was obtained. It is therefore concluded that diets high in flaxseed or flaxseed meal do not result in serum factors that are directly embryotoxic to organogenesis-staged rat embryos. This finding is consistent with the findings of a parallel in vivo rat teratology study where no significant embryotoxicity attributable to flaxseed exposure was observed.

Exposure to flaxseed or its purified lignan during suckling only or continuously does not alter reproductive indices in male and female offspring.

Based on the reported health benefits of flaxseed, many Canadians are choosing to consume flaxseed or flaxseed-containing foods. However, the safety of exposure to flaxseed during early life such as the suckling period has not been studied, despite the fact that components in flaxseed with potential hormone-like effects can be transferred to nursing offspring via mother's milk. Previous investigations demonstrated that maternal feeding of a 10% flaxseed diet during pregnancy and lactation resulted in estrogenic effects on reproductive indices among male and female offspring. These effects were attributed to the potential estrogenic activity of enterodiol and enterolactone, the two major mammalian lignans that are converted from secoisolariciresinol diglycoside (SDG) in flaxseed by colonic bacteria; however, the effect of exposure to purified SDG at the level of a 10% flaxseed diet was not studied. The objective of this study was to determine whether maternal feeding of flaxseed during lactation altered reproductive indices in male and female offspring. Rat dams were fed basal diet (BD) or BD containing either 100% flaxseed (10F) or the equivalent quantity of SDG present in the 10% (10S) flaxseed diet from the start of lactation until pups were 21 d old. At the end of lactation (postnatal day IPND] 21), suckling pups either continued on the mother's diet or were switched to BD until adolescence (PND 50) or young adulthood (PND 132) to determine if continuous exposure to flaxseed or SDG altered reproductive indices. The reproductive indices that were measured included anogenital distance from birth through PND 21, age and body weight at puberty onset (females only), estrous cycle length, reproductive organ weights at PND 50 and 132, and histological analysis of reproductive organs (uterus, ovaries, prostate) at PND 132. There were no significant effects of exposing male or female offspring to flaxseed or SDG during suckling only or during suckling through the postsuckling period on any of the reproductive indices measured. These findings are in contrast to the estrogenic effects observed in male and female offspring exposed to flaxseed during fetal life through suckling and suggest that fetal life is a more hormone-sensitive period of development. Although maternal feeding of flaxseed during lactation appears to be safe with respect to reproductive indices among offspring, future investigation is required to elucidate whether there are any long-term implications with respect to fertility.

The effect of maternal exposure to flaxseed on spermatogenesis in F(1) generation rats.

Pregnant Sprague-Dawley rats were exposed to a flaxseed (20 or 40%), flaxmeal (13 or 26%) or standard NIH AIN-93 (0% flaxseed control) diet throughout gestation and until their offspring were weaned. After weaning, F(1) generation males were placed in the same diet treatment groups as their mothers for 70 days. Statistically significant differences were not observed between either low-dose or high-dose flaxseed and flaxmeal-treated animals and the 0% flaxseed control animals for testis weights, homogenization resistant spermatid counts, daily sperm production rates, epididymal weights, seminal vesicle weights, seminiferous tubule fluid testosterone concentrations and the percentage of sperm abnormalities. The following statistically significant differences were observed when treated groups and the 0% flaxseed control groups were compared: (1) increases in serum LH in the 20% and 40% flaxseed treatment groups and in serum LH and testosterone in the 26% flaxmeal treatment group; (2) increases in the cauda epididymal weight from the 20% and 40% flaxseed groups; (3) increases in cauda epididymal sperm numbers/g epididymis from the 20% and 40% flaxseed and the 13% and 26% flaxmeal treatment groups; (4) a decrease in prostatic weight from the 20% flaxseed and 13% and 26% flaxmeal treatment groups. Prostate weight in the 40% flaxseed treatment group was lower but not statistically significantly different than the 0% flaxseed control group. Histological effects on spermatogenesis were not observed in either the control group, flaxmeal or the flaxseed treated groups.