Oil In Mice Research Articles

Anti-Inflammatory Effects of Thyme Essential Oil in Mice

Plant essential oils are plant secondary metabolites possessing various pharmacological properties, primarily anti-oxidative, antimicrobial or immunomodulatory ones. The aim of this work was to study the effects of thyme essential oil dietary administration in murine DTH/ CHS reaction, carrageenan paw oedema and TNBS colitis. Thyme essential oil was added to the murine diet at three concentrations (5000, 2500 and 1250 ppm) and fed to Balb/c mice. The extent of ear swelling in DTH/CHS reaction and paw oedema induced by carrageenan application was measured using the Mitutoyo thickness gauge. In the model of TNBS colitis we evaluated the changes in body weight, the colon weight : body weight ratio, bacterial translocation to mesenteric lymph nodes, and macroscopical and histological scores. IL-1β and IL-6 messenger RNA expression in colonic samples of one experimental group were assessed using quantitative real-time reverse transcriptase PCR. Dietary supplementation with 5000 ppm of thyme essential oil significantly decreased paw oedema and ear swelling. This thyme essential oil concentration caused a significant inhibition of total mRNA IL-1β expression in the mouse colon, and markedly decreased the macroscopic and microscopic scores of colitis. On the other hand, the 1250 ppm of thyme essential oil in diet increased ear oedema induced by oxazolone application in mice. Our study indicates that thyme essential oil is able to affect murine experimental inflammatory models depending on the concentration used. It is concluded that the anti-inflammatory effects of thyme essential oil should be interpreted with a caution due to its contradictory, dose-related effects.

Reinforcing effect for corn oil stimulus was concentration dependent in an operant task in mice

Corn oil is reported to elicit a conditioned place preference (CPP) in a CPP test in mice. To further investigate a reinforcing effect of corn oil, we studied whether the corn oil acts as a reinforcer under a progressive ratio (PR) schedule in the operant task. BALB/c mice were trained to lever press for sucrose and corn oil. After reaching a stable break-point for 100% corn oil, the PR test was conducted for various concentrations of corn oil (0%–100%). The reinforcing effect of corn oil was increased in a concentration-dependent manner under the PR schedule. A mineral oil and 0.3% xanthan gum as vehicles did not show any reinforcing effect in the PR test, suggesting that oily and viscous texture was not related to the reinforcing property of corn oil. The break-point for corn oil was attenuated by pretreatment with (−)-sulpiride, a D(2) antagonist, in the PR test. On the other hand, SCH23390, a D(1) antagonist, did not influence the break-point. Furthermore, the pretreatment with (−)-sulpiride or SCH23390 did not influence the intake of corn oil in a one-bottle test for 30 min, suggesting that the dopaminergic system is involved in the reinforcing effect but not the consumption of corn oil in mice. In conclusion, operant response to corn oil is concentration-dependently enhanced under the PR schedule. This reinforcing effect of corn oil is at least partly mediated through the dopaminergic systems via D(2) receptors.

Suppression of Postprandial Hypertriglyceridemia in Rats and Mice by Oolong Tea Polymerized Polyphenols

Oolong tea-polymerized polyphenols (OTPP) are characterized polyphenols produced from semi-fermented tea (oolong tea). In the present study, we evaluated the suppressive effects of oolong tea extract and OTPP on postprandial hypertriglyceridemia in rats and mice. Lymphatic recovery of triglycerides in rats cannulated in the thoracic duct was delayed by the administration of oolong tea extract at 100 and 200 mg per head, and more effectively than with green tea extract. OTPP delayed lymphatic triglyceride absorption at 20 mg/head, though (-)-epigallocatechin gallate (EGCG) did not do so at the same dose. OTPP also suppressed postprandial hypertriglyceridemia after administration of olive oil in mice. The area under the curve (AUC) of plasma triglycerides was significantly decreased, by 53% and 76%, in the 500 and 1,000 mg/kg OTPP groups respectively, as compared with the control group. These results suggest that OTPP is responsible for the suppression of hypertriglyceridemia by ingestion of oolong tea.

Mechanisms Involved in the Anti-Inflammatory Action of Inhaled Tea Tree Oil in Mice:

Tea tree oil (TTO) is well known as an antimicrobial and immunomodulatory agent. In the present study we confirmed the anti-inflammatory properties of TTO and investigated the involvement of the hypothalamic-pituitary-adrenal (HPA) axis in the immunomodulatory action of TTO administered by inhalation. Sexually mature, 6-8-week-old, C(57)BI(10) x CBA/H (F(1)) male mice were used. One group of animals was injected intra-peritoneally (ip) with Zymosan to elicit peritoneal inflammation and was then submitted to four sessions of TTO inhalation (15 mins each). Some of the mice were simultaneously injected ip with Antalarmin, a CRH-1 receptor antagonist, to block HPA axis functions. Twenty-four hours after the injections the mice were killed by CO(2) asphyxia, and peritoneal leukocytes (PTLs) were isolated and counted. Levels of reactive oxygen species (ROS) and cyclooxygenase (COX) activity in PTLs were assessed by fluorimetric and colorimetric assays, respectively. The results obtained show that sessions of TTO inhalation exert a strong anti-inflammatory influence on the immune system stimulated by Zymosan injection, while having no influence on PTL number, ROS level, and COX activity in mice without inflammation. The HPA axis was shown to mediate the anti-inflammatory effect of TTO; Antalarmin abolished the influence of inhaled TTO on PTL number and their ROS production in mice with experimental peritonitis, but it had no effect on these parameters in mice without inflammation.

Evaluation of the Hypolipemic Property of Camellia sinensis Var. ptilophylla on Postprandial Hypertriglyceridemia

A naturally decaffeinated tea, Camellia sinensis var. ptilophylla (cocoa tea), has long been popular in southern China as a healthy beverage. Our experiments indicate that a single oral administration of 500 mg/kg of cocoa tea extract suppresses increases in plasma triacylgycerol (TG) levels when fed with 5 mL/kg of olive or lard oil in mice and that the inhibition rates are 22.9% and 31.5%, respectively, compared with controls. Under the same condition, cocoa tea extract did not affect the level of plasma free fatty acid. Likewise, the extract reduced the lymphatic absorption of lipids at 250 and 500 mg/kg. Also, cocoa tea extract and polyphenols isolated from cocoa tea inhibit pancreatic lipase. These findings suggest that cocoa tea has hypolipemic activity, which may be due to the suppression of digestive lipase activity by the polyphenols contained within the tea.

Assessment of carcinogenic potential of repeated fish fried oil in mice

Our prior studies have shown that single topical treatment of repeated fish fried oil extract (RFFE), containing various polycyclic aromatic hydrocarbons (PAHs), to the dorsal epidermis of mice caused enhancement of DNA damage along with higher expression of p53 and p21WAF1 proteins and cell-cycle arrest. In the present study carcinogenic potential of repeated fish fried oil (RFFO) and RFFE was assessed. Single topical application of RFFO (100 microL/animal) and RFFE (100-500 microg/animal) to Swiss albino female mice resulted in significant induction (1.8- to 7.4-fold) of ornithine decarboxylase activity. Twice weekly topical application of methylcholanthrene (MCA) for 24 wk or single topical application of 7,12-dimethylbenzanthracene (DMBA) or RFFO or RFFE, as initiator followed by twice weekly application of 12-O-tetradecanoyl phorbol myristate acetate (TPA) as promoter for 24 wk, resulted in development of skin papillomas after 6, 7, 18, and 9 wk, respectively. The cumulative number of tumors in MCA, DMBA/TPA, RFFE (200 microg)/TPA, and RFFE (500 microg)/TPA groups were 276, 168, 34, and 58 after 24 wk while negligible or minimal initiating activity was noticed in RFFO/TPA group. No tumors were found in animals either given twice weekly topical application of RFFO or a single initiating dose of DMBA followed by twice weekly application of RFFO. Histopathology of skin of animals treated with RFFE/TPA showed marked proliferation of epidermal layers along with abnormal mitosis and multinucleated tumor appearance. Skin of animals in groups RFFO/TPA and DMBA/RFFO showed sloughing and regeneration of epidermal layers, oedema along with proliferation of fibroblasts. Histochemical localization of gamma-glutamyl transpeptidase was found to be substantially higher in skin of mice treated with RFFO/TPA and RFFE/TPA. Animals treated with RFFO/TPA, DMBA/RFFO, and RFFE/TPA resulted in significant induction of cutaneous aryl hydrocarbon hydroxylase (AHH) (421-432%), ethoxyresorufin-O-deethylase (252-316%), and glutathione S-transferase (133-245%) activities. Animals treated with RFFO/TPA, DMBA/RFFO, and RFFE/TPA led to significant reduction in glutathione content (39-44%) with a concomitant increase in lipid peroxidation (254-492%). Animals treated with RFFO/TPA and RFFE/TPA led a significant decrease in catalase (43-69%) and superoxide dismutase (20-31%) activities while glutathione reductase activity was found to be diminished (23-51%) in RFFO, RFFO/TPA, DMBA/RFFO, and RFFE/TPA treated groups. These results suggest that RFFE possess skin tumor initiating activity and that it may have weak promoting activity as well, which may involve free radicals.

Anti-inflammatory and anti-nociceptive activities of Pluchea quitoc (DC.) ethanolic extract

Pluchea quitoc DC. (Asteraceae), a plant widely distributed throughout Brazil and popularly known as “quitoco”, “madre-cravo” or “tabacarana”, is used in traditional medicine for the treatment of inflammation, as well as of digestive and respiratory diseases. The anti-inflammatory and anti-nociceptive activities of the ethanolic extract (EE) from aerial parts of this plant were evaluated in mice and rats. Oral treatment with the EE (1–2 g/kg, p.o.) decreased the paw oedema induced by carrageenan in rats, showed anti-nociceptive effects on the tail-flick test and on acid-induced writhing in mice, and inhibited both phases of pain (neurogenic and inflammatory) of the formalin test in rats. Topical application (EE 1.25, 2.5 and 5.0 mg) inhibited the ear oedema induced by croton oil in mice. The results support the folkloric use of the plant in inflammatory processes.

Unequivocal evidence of genotoxic potential of argemone oil in mice.

Consumption of mustard oil adulterated with argemone oil leads to a clinical condition, commonly referred to as "Epidemic Dropsy." Since in vitro studies have shown that sanguinarine, an active benzophenanthridine alkaloid of argemone oil, intercalates DNA molecule, the in vivo clastogenic and DNA damaging potential of argemone oil was investigated in mice. Swiss albino mice were intraperitoneally administered 0.5, 1.0, 2.0 and 4.0 ml/kg body wt. of argemone oil to analyze chromosome aberrations and micronucleus test, while 0.25, 0.5, 1.0 and 2.0 ml/kg body wt. were given for alkaline comet assay. The frequencies of chromosomal aberrations and micronucleated erythrocytes formation in mouse bone marrow cells increased in a dose-dependent manner following argemone oil treatment. However, significant induction in chromosomal aberrations (83%) and micronucleated erythrocytes formation (261%) were observed at a minimum dose of 1.0 ml/kg. The results of comet assay revealed DNA damage in blood, bone marrow and liver cells following argemone oil treatment. Olive tail moment (OTM) and tail DNA showed significant increase in bone marrow (35-44%) and blood cells (25-40%) even at a dose of 0.25 ml/kg body wt. of argemone oil. In liver cells, OTM was significantly increased (20%) at a dose of 0.25 ml/kg, while all the comet parameters including OTM, tail length and tail DNA showed significant increase (31-101%) at a dose of 0.5 ml/kg. These results clearly suggest that single exposure of argemone oil even at low doses produces genotoxic effects in mice.

Joint, muscle, and visceral pain: Non steroidal anti-inflammatory drugs are not effective on the referred hyperalgesia of visceral pain induced by intracolonic mustard oil in the mouse

Visceral pain is characterized by its spontaneous pain and referred hyperalgesia. Our aim was to examine the inhibitory effects of various NSAIDs on the pain behaviors and plasma extravasation induced by intracolonic mustard oil in mice. Adult male ICR mice were injected 50mg/kg of evans blue via tail vein for subsequent determination of plasma extravasation. Control group animals were given subcutaneous saline and experimental groups were given one of the following drugs: 1,3,10mg/kg of morphine; 10, 100mg/kg of ketoprofen; 5, 50mg/kg of tarasyn; 2, 20mg/kg of DFU (cyclooxygenase-2 inhibitor).Visceral pain related behaviors were counted for 20 min after intracolonic administration of 50 ulof 1.5% mustard oil. in order to test referred hyperalgesia, before intracolonic administrtion and 20 min after, the frequency of withdrawal responses to the application of von Frey hairs to the abdomen, foot and tail was tested. The colon was removed post-mortem and evans blue content measured. Visceral pain related behaviors were significantly inhibited by 3, 10 mg/kg of morphine, 50mg/kg of tarasyn, 100mg/kg of ketoprofen and 20mg/kg of DFU (P < 0.05). Response frequencies to the application of von Frey hairs were decreased by 3, 10mg/kg of morphine (P < 0.05), but not any doses of tarasyn, ketoprofen and DFU. Evans blue content was decreased by 100mg/kg of ketoprofen and 20mg/kg DFU (P < 0.05), but not other groups. These results suggest that the analgesic effects of NSAIDs on visceral pain could be mainly mediated by peripheral mechanism, reflected by inhibition of the pain behavior and inflammation, but not referred hyperalgesia.

Effects of Non Steroidal Anti-inflammatory Drugs on the Evans Blue Extravasation and Pain Behaviors Evoked by Mustard Oil Induced Visceral Pain in Mice: Comparison with Morphine

Background: Visceral pain is characterized by its spontaneous pain and referred hyperalgesia. Our aim was to examine the inhibitory effects of various NSAIDs on the pain behaviors, both spontaneously and mechanically evoked, and evans blue extravasation induced by intracolonic mustard oil in mice. Methods: 50 mg/kg of evans blue was injected to adult male ICR mice via tail vein for subsequent determination of plasma extravasation. The animals in the control group were given subcutaneous saline and those in experimental groups were given one of the following drugs: 1, 3, 10 mg/kg of morphine; 10, 100 mg/kg of ketoprofen; 5, 50 mg/kg of ketorolac; 2, 20 mg/kg of DFU (cyclooxygenase-2 inhibitor). Visceral pain-related behaviors were counted for 20 minutes after intracolonic administration of 50l of 1.5% mustard oil. In order to test referred hyperalgesia, before intracolonic administration and 20 min after the administration, the frequency of withdrawal responses to the application of von Frey hairs to the abdomen, foot and tail was tested. The colon was removed post-mortem and evans blue content was measured. Results: Visceral pain-related behaviors were significantly inhibited in the groups administered with 3 and 10 mg/kg of morphine, 50 mg/kg of ketorolac, 100 mg/kg of ketoprofen and 20 mg/kg of DFU (P

Antinociceptive and antidiarrhoeal activity of Zanthoxylum rhetsa

The methanolic extract of the Zanthoxylum rhetsa Roxb. stem bark, given by oral route to mice at doses of 250 and 500 mg/kg, significantly reduced the abdominal contraction induced by acetic acid and the diarrhoeal episodes induced by castor oil in mice.

Cannabinoid CB1-receptor mediated regulation of gastrointestinal motility in mice in a model of intestinal inflammation.

1. We have studied the effect of cannabinoid agonists (CP 55,940 and cannabinol) on intestinal motility in a model of intestinal inflammation (induced by oral croton oil in mice) and measured cannabinoid receptor expression, endocannabinoids (anandamide and 2-arachidonylglycerol) and anandamide amidohydrolase activity both in physiological and pathophysiological states. 2. CP 55,940 (0.03 - 10 nmol mouse(-1)) and cannabinol (10 - 3000 nmol mouse(-1)) were more active in delaying intestinal motility in croton oil-treated mice than in control mice. These inhibitory effects were counteracted by the selective cannabinoid CB(1) receptor antagonist SR141716A (16 nmol mouse(-1)). SR141716A (1 - 300 nmol mouse(-1)), administered alone, increased intestinal motility to the same extent in both control and croton oil-treated mice. 3. Croton oil-induced intestinal inflammation was associated with an increased expression of CB(1) receptor, an unprecedented example of up-regulation of cannabinoid receptors during inflammation. 4. High levels of anandamide and 2-arachidonylglycerol were detected in the small intestine, although no differences were observed between control and croton oil-treated mice; by contrast anandamide amidohydrolase activity increased 2 fold in the inflamed small intestine. 5. It is concluded that inflammation of the gut increases the potency of cannabinoid agonists possibly by 'up-regulating' CB(1) receptor expression; in addition, endocannabinoids, whose turnover is increased in inflamed gut, might tonically inhibit intestinal motility.

Preference for corn oil in olfactory-blocked mice in the conditioned place preference test and the two-bottle choice test

We studied the effects of olfactory stimuli on preference for corn oil in mice. In the conditioned place preference test, voluntary intake of 100% corn oil by both olfactory normal and ZnSO 4-induced olfactory-blocked (anosmic) mice resulted in their place preference for the corn oil-related box. In the olfactory normal mice, place preference was also observed by voluntary intake of linoleic acid as well as of corn oil. In the two-bottle choice test, normal mice showed significant preference for test fluids that contained corn oil at all concentrations (1 – 10%) tested relative to vehicle alone. However, the lower concentrations (1 and 3%) of corn oil were not preferred in the anosmic mice. These results suggested that stimuli other than olfaction contributed to the rewarding effects of corn oil, but at lower concentrations olfactory stimuli might act as a signal for the oil.

Opioidergic contribution to conditioned place preference induced by corn oil in mice

We previously reported that voluntary intake of corn oil in the light box showed place preference in the conditioned place preference (CPP) test in mice. In the present study, we investigated the contribution of opioidergic systems to the corn oil-induced CPP in mice. Acquisition of the place preference by corn oil intake was blocked by i.p. injections of an opioid μ antagonist, naloxone (0.1 and 0.3 mg/kg), and δ antagonists, 7-benzylidenenaltrexone (0.5 mg/kg) and naltriben (0.5 mg/kg) 15 min before conditioning. The opioid κ agonist U-50488H (1 and 3 mg/kg i.p.) also blocked corn oil-induced CPP. Naloxone (1 mg/kg, i.p.) and naltriben (0.5 mg/kg, i.p.) did not affect corn oil intake in the home cage. However, 7-benzylidenenaltrexone (0.5 mg/kg, i.p.) and U-50488H (1 mg/kg i.p.) decreased and increased the corn oil intake, respectively. These results suggested that the rewarding effects of corn oil in the CPP test are at least partially mediated via opioidergic systems through μ and δ receptors. Further, we showed that an opioid κ agonist reduced the rewarding effects of corn oil in the CPP test in mice, although it increased corn oil intake.

Developmental toxicity of carbon black oil in mice.

Carbon black oil (CBO) is a refinery side-stream product used to produce asphalt and other commercial products. CBO contains several classes of hydrocarbons, several of which are known to exhibit systemic and gestational toxicities, making this mixture a candidate for causing reproductive toxicity. Swiss-Webster mice were administered CBO (300, 350, 400 mg/kg/day) via oral gavage in a dosage volume of 10 microl/g body weight on gestation days (GD) 6-15. Uterine contents were evaluated on GD 18. Treatment with CBO at all dosage levels resulted in a high frequency of maternal clinical symptoms and a decrease in maternal weight gain. Decreased fetal viability was observed, manifested as a decrease in viable implants and, in a high percentage of treated dams, as early resorption of the entire litter. A significant reduction in fetal weight was also observed. However, neither structural malformations nor developmental delays in ossification were observed in any of the living offspring. To minimize maternal toxicity, the dosage range was lowered (100, 200, 300 mg/kg/day), and the concentration was adjusted such that the volume administered to each dam was decreased by 20%. In this trial, the only maternal effect observed was an increase in maternal liver weight at 200 and 300 mg/kg. The fetal lethality effects observed previously were reduced substantially. Nevertheless, the frequency of resorption among all treatment groups was higher statistically than in controls. These data support the hypothesis that CBO is reproductively toxic in Swiss-Webster mice at oral doses of >/=100 mg/kg/day.

P–665 - An investigation into the mechanism of skin inflammation induced by topical application of mustard oil in mice.

P–665 - An investigation into the mechanism of skin inflammation induced by topical application of mustard oil in mice.

Involvement of interleukin-6 in activation of lysosomal cathepsin and atrophy of muscle fibers induced by intramuscular injection of turpentine oil in mice.

Serum IL-6 level increased after the injection of turpentine oil into the right gastrocnemius muscle in mice. The mRNA level of IL-6 was highest in the injected muscle at 12 h after injection, but was not identified in the opposite muscle. The activities of cathepsins B and B+L started to elevate after 12 h in the injected muscle and markedly increased after day 3. Likewise, the mRNA levels of cathepsins B and L markedly increased from day 1 to day 5 in the injected muscle. However, a very mild increase was also observed in the opposite muscle. Immunohistochemical staining of cathepsins B and L exhibited positive reactions as fine granules in myofibers at 12 h and strong positive reactions in the infiltrating macrophages at 3 days. Atrophy of myofibers type 1 and 2 was evident in a time-dependent manner in the injected muscle. Treatment with rat anti-mouse IL-6 receptor monoclonal antibody inhibited the increase in cathepsin activities in the injected muscle. We conclude that IL-6 produced in the inflamed muscle is involved in the process of muscle degeneration, especially through the activation of lysosomal cathepsins.

Investigations on the gastroprotective and antidiarrhoeal properties of ternatin, a tetramethoxyflavone from Egletes viscosa.

The study was designed to verify the gastroprotective and antidiarrhoeal effects of ternatin, tetramethoxyflavone isolated from Egletes viscosa Less. The gastroprotective function of ternatin was evaluated in rats against gastric mucosal damage induced by hypothermic restraint stress, absolute ethanol, and indomethacin, whereas the antidiarrhoeal activity was investigated by studying its influence on gastrointestinal transit as measured by a charcoal marker and on castor oil-induced accumulation of intestinal fluid in mice and also on contractile responses evoked by acetylcholine, histamine, serotonin, and barium chloride in isolated guinea-pig ileum. The results demonstrate that pretreatment of animals with the plant flavonoid (25 and 50 mg/kg, i.p.) produces a significant inhibition of gastric lesions induced by ethanol but not those induced by restraint stress or indomethacin and suggest a probable involvement of a prostaglandins-independent mechanism of gastroprotection. At similar doses, both the intestinal transit as well as the accumulation of intestinal fluids induced by castor oil in mice were significantly inhibited by ternatin. Furthermore, the flavonoid antagonised the contractile responses evoked by different agonists on guinea-pig ileum in vitro and its inhibitory potential for the drugs are in the order of acetylcholine > histamine > serotonin > barium chloride. Taken together, these results point out a possible antidiarrhoeal effect of ternatin since inhibition of intestinal motility and secretion can greatly control clinical diarrhoea.

Analgesic and Anti-inflammatory Activities of the Aqueous Extract of Plantago major L.

This study aimed to validate the pharmacological effects of Plantago major L., a medicinal plant used to decrease pain and inflammation. The aqueous extract (AE) was prepared from the dried ground leaves. Pretreatment with AE (1 g/kg, p.o.) decreased writhing induced by acetic acid in mice, but it did not change the tail flick responses to heat nociceptive stimuli. In rats, AE (1 g/kg, p.o.) reduced the paw edema and pleurisy induced by carrageenin, but it did not alter the paw edema induced by dextran. The effect of AE on the carrageenin inflammatory responses was more intense than that obtained on the ear edema induced by croton oil in mice. In addition, daily treatment with AE (1 g/kg/day during 8 days, p.o.) inhibited the exudative process induced by croton oil injected into the air pouch of rats. The results indicate that the aqueous extract of Plantago major is endowed with effective antiinflammatory and analgesic activities.

Development and application of non-invasive biomarkers for carcinogen-DNA adduct analysis in occupationally exposed populations

Biological monitoring of exposures to carcinogenic compounds in the workplace can be a valuable adjunct to environmental sampling and occupational medicine. Carcinogen-DNA adduct analysis has promise as a biomarker of effective dose if target organ samples can be obtained non-invasively. We have developed non-invasive techniques using exfoliated urothelial and bronchial cells collected in urine and sputum, respectively. First morning urine samples were collected from 33 workers exposed to benzidine or benzidine-based dyes and controls matched for age, education, and smoking status. Sufficient DNA for 32P-postlabelling analysis was obtained from every sample. Mean levels of a specific DNA adduct (which co-chromatographed with standard characterized by MS) were elevated significantly in the benzidine-exposed workers relative to controls. In addition, workers exposed to benzidine had higher adduct levels than those exposed to benzidine-based dyes. This study demonstrates the usefulness of these non-invasive techniques for exposure/effect assessment. To be useful in occupational studies, biomarkers must also be sensitive to exposure interventions. We have conducted topical application studies of used gasoline engine oils in mice and found that the levels of carcinogen-DNA adducts in skin and lung can be significantly lowered if skin cleaning is conducted in a timely manner. The combination of useful, non-invasive techniques to monitor exposure and effect and industrial hygiene interventions can be used to detect and prevent exposures to a wide range of carcinogens including those found in used gasoline engine oils and jet exhausts.