PBDE-47 and PBDE mixture (DE-71) toxicities and liver transcriptomic changes at PND 22 after in utero/postnatal exposure in the rat.

Pentabromodiphenyl ethers (PBDE) are found in human tissue, in household dust, and in the environment, and a particular concern is the potential for the induction of cancer pathways from these fat-soluble persistent organic pollutants. Only one PBDE cancer study has been conducted and that was for a PBDE mixture (DE-71). Because it is not feasible to test all PBDE congeners in the environment for cancer potential, it is important to develop a set of biological endpoints that can be used in short-term toxicity studies to predict disease outcome after long-term exposures. In this study, PBDE-47 was selected as the test PBDE congener to evaluate and compare toxicity to that of the carcinogenic PBDE mixture. The toxicities of PBDE-47 and the PBDE mixture were evaluated at PND 22 in Wistar Han rat (Crl: WI (Han)) pups after in utero/postnatal exposure (0, 0.1, 15, or 50 mg/kg; dams, GD6-21; pups, PND 12-PND 21; oral gavage daily dosing). By PND 22, PBDE-47 caused centrilobular hypertrophy and fatty change in liver, and reduced serum thyroxin (T4) levels; similar effects were also observed after PBDE mixture exposure. Transcriptomic changes in the liver included induction of cytochrome p450 transcripts and up-regulation of Nrf2 antioxidant pathway transcripts and ABC membrane transport transcripts. Decreases in other transport transcripts (ABCG5 & 8) provided a plausible mechanism for lipid accumulation, characterized by a treatment-related liver fatty change after PBDE-47 and PBDE mixture exposure. The benchmark dose calculation based on liver transcriptomic data was generally lower for PBDE-47 than for the PBDE mixture. The up-regulation of the Nrf2 antioxidant pathway and changes in metabolic transcripts after PBDE-47 and PBDE mixture exposure suggest that PBDE-47, like the PBDE mixture (NTP 2016, TR 589), could be a liver toxin/carcinogen after long-term exposure.

Carcinogenic activity of pentabrominated diphenyl ether mixture (DE-71) in rats and mice.

Pentabrominated diphenyl ether (PBDE) flame retardants have been phased out in Europe and in the United States, but these lipid soluble chemicals persist in the environment and are found human and animal tissues. PBDEs have limited genotoxic activity. However, in a 2-year cancer study of a PBDE mixture (DE-71) (0, 3, 15, or 50 mg/kg (rats); 0, 3, 30, or 100 mg/kg (mice)) there were treatment-related liver tumors in male and female Wistar Han rats [Crl:WI(Han) after in utero/postnatal/adult exposure, and in male and female B6C3F1 mice, after adult exposure. In addition, there was evidence for a treatment-related carcinogenic effect in the thyroid and pituitary gland tumor in male rats, and in the uterus (stromal polyps/stromal sarcomas) in female rats. The treatment-related liver tumors in female rats were unrelated to the AhR genotype status, and occurred in animals with wild, mutant, or heterozygous Ah receptor. The liver tumors in rats and mice had treatment-related Hras and Ctnnb mutations, respectively. The PBDE carcinogenic activity could be related to oxidative damage, disruption of hormone homeostasis, and molecular and epigenetic changes in target tissue. Further work is needed to compare the PBDE toxic effects in rodents and humans.

Immunohistochemical Expression of Cyclin D1, Cytokeratin 20, and Uroplakin III in Proliferative Urinary Bladder Lesions Induced by o-Nitroanisole in Fischer 344/N Rats.

o-Nitroanisole is an intermediate in the manufacture of azo dyes. In a National Toxicology Program stop-exposure study,o-nitroanisole induced hyperplasia, papillomas, and papillary carcinomas in the urinary bladder of Fischer 344/N rats.o-Nitroanisole was investigated since occupational or environmental exposure to aniline and azo dyes is a risk factor for urinary bladder cancer in humans. The current study describes the morphology of urinary bladder neoplasms seen in rats with respect to those observed in humans. This study also evaluated immunohistochemical expression of the cell cycle-related proteins cyclin D1 and p53 and the differentiation markers cytokeratin 20 and uroplakin III in hyperplastic (n= 11) and neoplastic (n= 6 papillomas,n= 11 carcinomas) lesions of the urinary bladder epithelium from rats treated with o-nitroanisole and in normal (n= 6) urinary bladders from untreated rats. The tumors observed were more similar to the papillary type rather than the muscle-invasive type of urinary bladder cancer in humans. The preneoplastic and neoplastic lesions observed suggest progression from hyperplasia to papilloma to papillary carcinoma. With neoplastic progression (hyperplasia to papilloma to carcinoma), cyclin D1 immunoreactivity progressively increased in intensity, percentage of cells staining, and distribution. Overexpression of p53 was not found. Cytokeratin 20 staining decreased in superficial cells, while uroplakin III staining increased in intermediate and basal cells with progression from hyperplasia to carcinoma. The results are consistent with increased cell cycle dysregulation or proliferation (cyclin D1), decreased differentiation (cytokeratin 20), and abnormal differentiation (uroplakin III) as lesions progress toward malignancy.

Environmental chemical exposure may contribute to uterine cancer development: studies with tetrabromobisphenol A.

Tetrabromobisphenol A (TBBPA), a widely used flame retardant, caused uterine tumors in rats. In this study, TBBPA was administered to male and female Wistar Han rats and B6C3F1/N mice by oral gavage in corn oil for 2 years at doses up to 1,000 mg/kg. TBBPA induced uterine epithelial tumors including adenomas, adenocarcinomas, and malignant mixed Müllerian tumors (MMMTs). In addition, endometrial epithelial atypical hyperplasia occurred in TBBPA-treated rats. Also found to be related to TBBPA treatment, but at lower incidence and at a lower statistical significance, were testicular tumors in rats, and hepatic tumors, hemangiosarcomas (all organs), and intestinal tumors in male mice. It is hypothesized that the TBBPA uterine tumor carcinogenic mechanisms involve altered estrogen levels and/or oxidative damage. TBBPA treatment may affect hydroxysteroid-dehydrogenase-17ß (HSD17ß) and/or sulfotransferases, enzymes involved in estrogen homeostasis. Metabolism of TBBPA may also result in the formation of free radicals. The finding of TBBPA-mediated uterine cancer in rats is of concern because TBBPA exposure is widespread and endometrial tumors are a common malignancy in women. Further work is needed to understand TBBPA cancer mechanisms.

The concentration of bisphenol A in urine is affected by specimen collection, a preservative, and handling.

In urine specimens that were collected from pregnant women in a large cohort, 24% contained more than 10 ng/ml of total bisphenol A (BPA), suggesting external contamination. Therefore, we conducted an investigation of the source(s) of extraneous BPA in the specimens. We found that under the conditions used to collect urine specimens in the epidemiologic study, contamination with BPA occurred, and by two separate mechanisms.

Structure-activity relationships for perfluoroalkane-induced in vitro interference with rat liver mitochondrial respiration.

Perfluorinated alkyl acids (PFAAs) represent a broad class of commercial products designed primarily for the coatings industry. However, detection of residues globally in a variety of species led to the discontinuation of production in the U.S. Although PFAAs cause activation of the PPARα and CAR nuclear receptors, interference with mitochondrial bioenergetics has been implicated as an alternative mechanism of cytotoxicity. Although the mechanisms by which the eight carbon chain PFAAs interfere with mitochondrial bioenergetics are fairly well described, the activities of the more highly substituted or shorter chain PFAAs are far less well characterized. The current investigation was designed to explore structure-activity relationships by which PFAAs interfere with mitochondrial respiration in vitro. Freshly isolated rat liver mitochondria were incubated with one of 16 different PFAAs, including perfluorinated carboxylic, acetic, and sulfonic acids, sulfonamides and sulfamido acetates, and alcohols. The effect on mitochondrial respiration was measured at five concentrations and dose-response curves were generated to describe the effects on state 3 and 4 respiration and respiratory control. With the exception of PFOS, all PFAAs at sufficiently high concentrations (>20µM) stimulated state 4 and inhibited state 3 respiration. Stimulation of state 4 respiration was most pronounced for the carboxylic acids and the sulfonamides, which supports prior evidence that the perfluorinated carboxylic and acetic acids induce the mitochondrial permeability transition, whereas the sulfonamides are protonophoric uncouplers of oxidative phosphorylation. In both cases, potency increased with increasing carbon number, with a prominent inflection point between the six and eight carbon congeners. The results provide a foundation for classifying PFAAs according to specific modes of mitochondrial activity and, in combination with toxicokinetic considerations, establishing structure-activity-based boundaries for initial estimates of risk for noncancer endpoints for PFAAs for which minimal in vivo toxicity testing currently exists.

Tubal ligation in relation to menopausal symptoms and breast cancer risk.

BACKGROUND: Local inflammation after tubal ligation may affect ovarian function and breast cancer risk. METHODS: We analysed tubal ligation, menopausal characteristics, and breast cancer risk in the Sister Study cohort (N=50,884 women). RESULTS: Tubal ligation was associated with hot flashes (hazard ratio (HR) 1.09; 95% confidence interval (CI): 1.06-1.12) but not menopausal age (HR 0.99; 95% CI: 0.96-1.02). Tubal ligation did not have an impact on breast cancer overall (HR 0.95; 95% CI: 0.85-1.06), but had a suggested inverse relation with oestrogen receptor+/progesterone receptor+ invasive tumours (HR 0.84; 95% CI: 0.70-1.01), possibly because of subsequent hysterectomy/bilateral oophorectomy. CONCLUSION: Tubal ligation does not influence overall breast cancer risk.

Urethral carcinoma and hyperplasia in male and female B6C3F1 mice treated with 3,3',4,4'-tetrachloroazobenzene (TCAB).

B6C3F1 mice chronically exposed to 3,3',4,4'-tetrachloroazobenzene (TCAB), a contaminant of dichloroaniline-derived herbicides, developed a number of neoplastic and nonneoplastic lesions, including carcinoma of the urinary tract. Groups of fifty male and fifty female B6C3F1 mice were exposed by gavage to TCAB at dose levels of 0, 3, 10, and 30 mg/kg five days a week for two years. Control animals received corn oil:acetone (99:1) vehicle. Decreased survival of male mice in the mid-dose group and of male and female mice in the high-dose groups was related mainly to the occurrence of urethral transitional cell (urothelial) carcinoma and resulting urinary obstruction. Increased urethral transitional cell carcinomas were seen in all treated male groups in a dose-related manner as well as in the females treated with 30 mg/kg TCAB. Administration of TCAB was also associated with increased transitional cell hyperplasia of the urethra. Most nonneoplastic lesions of the urogenital tract were considered secondary to local invasion and urinary obstruction by the urethral transitional cell carcinomas. The mechanism of tumor induction is uncertain, but the high frequency of tumors in the proximal urethra of male mice suggests that the neoplasms result from the exposure of a susceptible population of urothelial cells to a carcinogenic metabolite of TCAB.

Chronic toxicity and carcinogenicity studies of chromium picolinate monohydrate administered in feed to F344/N rats and B6C3F1 mice for 2 years.

Trivalent chromium (Cr(III)) has been proposed to be an essential element, which may increase sensitivity to insulin and thus participate in carbohydrate and lipid metabolism. Humans ingest Cr(III) both as a natural dietary constituent and in dietary supplements taken for weight loss and antidiabetic effects. Chromium picolinate (CP), a widely used supplement, contains Cr(III) chelated with three molecules of picolinic acid and was formulated in an attempt to improve the absorption of Cr(III). In order to examine the potential for CP to induce chronic toxicity and carcinogenicity, the NTP conducted studies of the monohydrate form (CPM) in groups of 50 male and female F344/N rats and B6C3F1 mice exposed in feed to concentrations of 0, 2000, 10,000 or 50,000 ppm for 2 years; exposure concentrations were selected following review of the data from NTP 3-month toxicity studies. Exposure to CPM did not induce biologically significant changes in survival, body weight, feed consumption, or non-neoplastic lesions in rats or mice. In male rats, a statistically significant increase in the incidence of preputial gland adenoma at 10,000 ppm was considered an equivocal finding. CPM was not carcinogenic to female rats or to male or female mice.

Carcinogenesis studies of cresols in rats and mice.

Cresols, monomethyl derivatives of phenol, are high production chemicals with potential for human exposure. The three isomeric forms of cresol are used individually or in mixtures as disinfectants, preservatives, and solvents or as intermediates in the production of antioxidants, fragrances, herbicides, insecticides, dyes, and explosives. Carcinogenesis studies were conducted in groups of 50 male F344/N rats and 50 female B6C3F1 mice exposed to a 60:40 mixture of m- and p-cresols (m-/p-cresol) in feed. Rats and mice were fed diets containing 0, 1500, 5000, or 15,000 ppm and 0, 1000, 3000, or 10,000 ppm, respectively. Survival of each exposed group was similar to that of their respective control group. Mean body weight gains were depressed in rats exposed to 15,000 ppm and in mice exposed to 3000 ppm and higher. A decrease of 25% over that of controls for the final mean body weight in mice exposed to 10,000 ppm appeared to be associated with lack of palatability of the feed. A marginally increased incidence of renal tubule adenoma was observed in the 15,000-ppm-exposed rats. The increased incidence was not statistically significant, but did exceed the range of historical controls. No increased incidence of hyperplasia of the renal tubules was observed; however, a significantly increased incidence of hyperplasia of the transitional epithelium associated with an increased incidence of nephropathy was observed at the high exposure concentration. The only significantly increased incidence of a neoplastic lesion related to cresol exposure observed in these studies was that of squamous cell papilloma in the forestomach of 10,000-ppm-exposed mice. A definitive association with irritation at the site-of-contact could not be made because of limited evidence of injury to the gastric mucosa at the time of necropsy. However, given the minimal chemical-related neoplastic response in these studies, it was concluded that there was no clear evidence of carcinogenicity in male rats or female mice exposed to the cresol mixture.

Genetic susceptibility to progressive massive fibrosis in coal miners.

Progressive massive fibrosis (PMF) is a chronic interstitial lung disease with a complex aetiology that can occur after cumulative dust exposure. A case-control study was conducted to test the hypothesis that single nucleotide polymorphisms (SNPs) within genes involved in inflammatory and fibrotic processes modulate the risk of PMF development. The study population consisted of 648 underground coal miners participating in the National Coal Workers Autopsy Study, of which 304 were diagnosed with PMF. SNPs that influence the regulation of interleukin (IL)-1, IL-6, tumour necrosis factor-alpha, transforming growth factor-beta1, vascular endothelial growth factor (VEGF), epidermal growth factor intercellular cell adhesion molecule (ICAM)-1 and matrix metalloproteinase-2 genes were determined using a 5'-nuclease real-time PCR assay. There were no significant differences in the distribution of any individual SNP or haplotype between the PMF and control groups. However, the polygenotype of VEGF +405/ICAM-1 +241/IL-6 -174 (C-A-G) conferred an increased risk for PMF (odds ratio 3.4, 95% confidence interval 1.3-8.8). The present study suggests that the examined genetic variations that help regulate inflammatory and fibrotic processes are unlikely to strongly influence susceptibility to this interstitial lung disease, although the role of vascular endothelial growth factor, intercellular cell adhesion molecule-1 and interleukin-6 polymorphisms in the development of progressive massive fibrosis may require further investigation.

Toxicity and carcinogenicity studies of 4-methylimidazole in F344/N rats and B6C3F1 mice.

4-Methylimidazole (4MI) is used in the manufacture of pharmaceuticals, photographic chemicals, dyes and pigments, cleaning and agricultural chemicals, and rubber. It has been identified as a by-product of fermentation in foods and has been detected in mainstream and side stream tobacco smoke. 4MI was studied because of its high potential for human exposure. Groups of 50 male and 50 female F344/N rats were fed diets containing 0-, 625-, 1,250-, or 2,500 ppm 4MI (males) or 0-, 1,250-, 2,500-, or 5,000 ppm 4MI (females) for 106 weeks. Based on the food consumption the calculated average daily doses were approximately 30, 55, or 115 mg 4MI/kg body weight to males and 60, 120, or 250 mg 4MI/kg to females. Survival of all exposed groups of males and females was similar to that of the control groups. The mean body weights of males in the 1,250- and 2,500 ppm groups and females in the 2,500- and 5,000 ppm groups were less than those of the control groups throughout the study. Feed consumption by 5,000 ppm females was less than that by the controls. Clonic seizures, excitability, hyperactivity, and impaired gait were observed primarily in 2,500- and 5,000 ppm females. The incidence of mononuclear cell leukemia in the 5,000 ppm females was significantly greater than that in the controls. The incidences of hepatic histiocytosis, chronic inflammation, and focal fatty change were significantly increased in all exposed groups of male and female rats. The incidences of hepatocellular eosinophilic and mixed cell foci were significantly increased in 2,500 ppm males and 5,000 ppm females. Groups of 50 male and 50 female B6C3F1 mice were fed diets containing 0-, 312-, 625-, or 1,250 ppm 4MI for 106 weeks. Based on the food consumption the calculated average daily doses were approximately 40, 80, or 170 mg 4MI/kg body weight to males and females. Survival of all exposed groups of males and females was similar to that of the control groups. Mean body weights of males and females in the 1,250 ppm groups and that in the 312- and 625 ppm females were less than those of the control groups. Feed consumption by exposed groups of male and female mice was similar to that by the controls. The incidences of alveolar/bronchiolar adenoma in all exposed groups of females, alveolar/bronchiolar carcinoma in 1,250 ppm males, and alveolar/bronchiolar adenoma or carcinoma (combined) in 1,250 ppm males and 625- and 1,250 ppm females were significantly greater than those in the control groups. The incidence of alveolar epithelial hyperplasia was significantly increased in the 1,250 ppm females. 4MI is carcinogenic inducing alveolar/bronchiolar adenoma and carcinoma in male and female mice. 4MI may also induce mononuclear cell leukemia in female rats.

Induction of thyroid and liver tumors by chronic exposure to 2-methylimidazole in F344/N rats and B6C3F1 mice.

2-Methylimidazole (2MI) has been identified as a by-product of fermentation and is detected in foods and mainstream and side-stream tobacco smoke. It is used in the manufacture of pharmaceuticals, photographic chemicals, dyes and pigments, agricultural chemicals, and rubber. Carcinogenicity studies of 2MI were conducted because of its high potential for human exposure and a lack of carcinogenicity data. Groups of male and female Fischer 344/N rats were fed diets containing 0, 300, 1,000, or 3,000 ppm (males) or 0, 1,000, 2,500, or 5,000 ppm (females) 2MI for 106 weeks and groups of male and female B6C3F1 mice were fed 0, 625, 1,250, or 2,500 ppm 2MI for 105 weeks. Animals in each group were sacrificed at 8 days, 14 weeks, and 6 months for determinations of serum thyroid hormone and liver enzyme levels and histopathological examinations and at 2 years for evaluations of neoplastic lesions. In rats, 2MI administration reduced serum thyroxine and triiodothyronine and increased thyroid stimulating hormone levels. 2MI administration also increased total hepatic UDP-glucuronosyltransferase levels. At 2 years, the incidences of thyroid follicular cell hyperplasia, adenoma or carcinoma (combined), as well as follicular mineralization were increased. The incidences of hepatocellular adenoma or carcinoma (combined) in the two highest dose groups of males and females were also increased. The incidences of mixed cell focus in males and females were also significantly increased. In mice, the incidences of thyroid follicular cell hypertrophy and hyperplasia were significantly increased in the high dose males and females. The incidence of thyroid follicular cell adenoma in the 2,500 ppm males was significantly greater than that in the control group. The incidences of hepatocellular adenoma or carcinoma (combined) were significantly increased in all exposed groups of males and in the 2,500 ppm females. Significant increases in incidences were also observed in spleen hematopoietic cell proliferation in both sexes and bone marrow hyperplasia, chronic active inflammation of the epididymis, sperm granuloma, and germinal epithelial atrophy of the testis in males. Under these experimental conditions, carcinogenic activity of 2MI was demonstrated in male and female rats and mice.

Stimulatory and inhibitory effects of genistein on human uterine leiomyoma cell proliferation are influenced by the concentration.

BACKGROUND: Due to dietary exposure of women to genistein, a soy-derived phytoestrogen, and the estrogen responsiveness of uterine leiomyomas 'fibroids', we evaluated the effects of genistein (0.001-50 microg/ml) on human uterine leiomyoma (UtLM) cells versus uterine smooth muscle cells (UtSMCs) in vitro. METHODS: Light microscopy was used to determine the effects of genistein on cell morphology. Proliferation was assessed using a colorimetric assay and proliferating cell nuclear antigen (PCNA) immunocytochemistry. Flow cytometry was used to quantitate cells in the S-phase and those undergoing apoptosis. A fluorometric assay and confocal microscopy were used to detect caspase-3 activity and apoptotic bodies, respectively. RESULTS: In UtLM cells, low concentrations (< or = 1 microg/ml) of genistein stimulated proliferation, increased PCNA labeling and the percentage of cells in the S-phase, but this did not occur in UtSMCs. Higher concentrations (> or = 10 microg/ml) of genistein adversely affected the morphology, significantly inhibited proliferation, decreased PCNA labeling, increased caspase-3 activity and induced apoptosis in both cell types. CONCLUSIONS: Genistein's effects are concentration-dependent in both cell lines. Lower concentrations elicit proliferative effects on UtLM cells only; whereas, higher concentrations alter morphology, inhibit proliferation, and increase caspase activity and apoptosis in both cell types, with the latter two effects being more extensive in UtSMCs.

Carcinogenesis studies of benzophenone in rats and mice.

Benzophenone, an aryl ketone, is used primarily as a photoinitiator and fragrance enhancer. Groups of 50 male and 50 female F344 rats and B6C3 F1 mice were fed diets containing 0, 312, 625, and 1250 ppm benzophenone for 105 weeks. Survival of males exposed to 1250 ppm benzophenone was significantly less than that of controls. There was a positive trend in the incidence of renal tubule adenoma in male rats; these neoplasms were accompanied by significantly increased incidences of renal tubule hyperplasia. Increased incidences of mononuclear cell leukemia were observed in male rats exposed to 312 or 625 ppm benzophenone and in female rats exposed to 625 ppm benzophenone. Liver lesions observed included significantly increased incidences of hepatocytic centrilobular hypertrophy in all exposed groups of rats. In mice, survival of all exposed groups was generally similar to that of the control groups. In male mice, there were significantly increased incidences of hepatocellular adenoma in the 625 and 1250 ppm groups. In female mice, the incidences of hepatocellular adenoma in the 625 and 1250 ppm groups were higher than expected after adjusting for the lower body weights in these groups. The incidences of kidney nephropathy in exposed groups of female mice, as well as the severity of nephropathy in exposed groups of males, were significantly increased. The incidences of metaplasia of the olfactory epithelium were significantly increased in 1250 ppm mice. Rare histiocytic sarcomas were observed in female rats and mice in the 625 and 1250 ppm groups. Under the conditions of these 2-year studies, there was some evidence of carcinogenic activity of benzophenone in male F344/N rats based on increased incidences of renal tubule adenoma. There was equivocal evidence of carcinogenic activity of benzophenone in female F344/N rats based on the marginal increased incidences of mononuclear cell leukemia and histiocytic sarcoma. There was some evidence of carcinogenic activity of benzophenone in male B6C3F(1) mice based on increased incidences of hepatocellular neoplasms, primarily adenoma. There was some evidence of carcinogenic activity of benzophenone in female B6C3F(1) mice based on increased incidences of histiocytic sarcoma; the incidences of hepatocellular adenoma in female B6C3F(1) mice may have been related to benzophenone exposure.

Absence of acrylamide-induced genotoxicity in CYP2E1-null mice: evidence consistent with a glycidamide-mediated effect.

Acrylamide, an animal carcinogen and germ cell mutagen present at low (ppm) levels in heated carbohydrate-containing foodstuffs, is oxidized by cytochrome P4502E1 (CYP2E1) to the epoxide glycidamide, which is believed to be responsible for the mutagenic and carcinogenic activity of acrylamide. We recently reported a comparison of the effects of acrylamide on the genetic integrity of germ cells of male wild-type and CYP2E1-null mice [B.I. Ghanayem, K.L. Witt, L. El-Hadri, U. Hoffler, G.E. Kissling, M.D. Shelby, J.B. Bishop, Comparison of germ-cell mutagenicity in male CYP2E1-null and wild-type mice treated with acrylamide: evidence supporting a glycidamide-mediated effect, Biol. Reprod. 72 (2005) 157-163]. In those experiments, dose-related increases in dominant lethal mutations were detected in uterine contents of female mice mated to acrylamide-treated wild-type males but not CYP2E1-null males, clearly implicating CYP2E1-mediated formation of glycidamide in the induction of genetic damage in male germ cells. We hypothesized that acrylamide-induced somatic cell damage is also caused by glycidamide. Therefore, to examine this hypothesis, female wild-type and CYP2E1-null mice were administered acrylamide (0, 25, 50mg/kg) by intraperitoneal injection once daily for 5 consecutive days. Twenty-four hours after the final treatment, blood and tissue samples were collected. Erythrocyte micronucleus frequencies were determined using flow cytometry and DNA damage was assessed in leukocytes, liver, and lung using the alkaline (pH>13) single cell gel electrophoresis (Comet) assay. Results were consistent with the earlier observations in male germ cells: significant dose-related increases in micronucleated erythrocytes and DNA damage in somatic cells were induced in acrylamide-treated wild-type but not in the CYP2E1-null mice. These results support the hypothesis that genetic damage in somatic and germ cells of mice-treated with acrylamide is dependent upon metabolism of the parent compound by CYP2E1. This dependency on metabolism has implications for the assessment of human risks resulting from occupational or dietary exposure to acrylamide. CYP2E1 polymorphisms and variability in CYP2E1 activity associated with, for example, diabetes, obesity, starvation, and alcohol consumption, may result in altered metabolic efficiencies leading to differential susceptibilities to acrylamide toxicities in humans.

Comparison of germ cell mutagenicity in male CYP2E1-null and wild-type mice treated with acrylamide: evidence supporting a glycidamide-mediated effect.

Acrylamide is an animal carcinogen and probable human carcinogen present in appreciable amounts in heated carbohydrate-rich foodstuffs. It is also a germ cell mutagen, inducing dominant lethal mutations and heritable chromosomal translocations in postmeiotic sperm of treated mice. Acrylamide's affinity for male germ cells has sometimes been overlooked in assessing its toxicity and defining human health risks. Previous investigations of acrylamide's germ cell activity in mice showed stronger effects after repeated administration of low doses compared with a single high dose, suggesting the possible involvement of a stable metabolite. A key oxidative metabolite of acrylamide is the epoxide glycidamide, generated by cytochrome P4502E1 (CYP2E1). To explore the role of CYP2E1 metabolism in the germ cell mutagenicity of acrylamide, CYP2E1-null and wild-type male mice were treated by intraperitoneal injection with 0, 12.5, 25, or 50 mg acrylamide (5 ml saline)(-1) kg(-1) day(-1) for 5 consecutive days. At defined times after exposure, males were mated to untreated B6C3F1 females. Females were killed in late gestation and uterine contents were examined. Dose-related increases in resorption moles (chromosomally aberrant embryos) and decreases in the numbers of pregnant females and the proportion of living fetuses were seen in females mated to acrylamide-treated wild-type mice. No changes in any fertility parameters were seen in females mated to acrylamide-treated CYP2E1-null mice. Our results constitute the first unequivocal demonstration that acrylamide-induced germ cell mutations in male mice require CYP2E1-mediated epoxidation of acrylamide. Thus, CYP2E1 polymorphisms in human populations, resulting in variable enzyme metabolic activities, may produce differential susceptibilities to acrylamide toxicities.

Benefits of computerized outcome analysis in diabetes management.

OBJECTIVE: To observe the effects of a computerized relational database designed to measure outcomes and enhance adherence to recommended diabetes management guidelines in a specialty private practice setting. METHODS: DiaTrends, a software program specifically designed to monitor the processes and outcomes of diabetes care, was introduced in a private endocrinology practice in 1996. Information on all patients with diabetes (N = 1,096) was recorded in the database. Reports ("queries") were developed to monitor the adherence to recommended guidelines and to assess the outcomes of care for patients with diabetes treated with glucose-lowering medications. Glycosylated hemoglobin (HbA(1c)) and lipid control were selected from the many outcomes and processes of care monitored as the basis of this report. RESULTS: Data were collected on 1,096 patients between 1996 and 1998. We were able to monitor adherence to published diabetes guidelines and to document the outcomes. Parallel trends toward improvement were noted in both HbA(1c) and lipid variables. The average HbA(1c) achieved for the entire patient population was 7.3%. CONCLUSION: Using a computerized database to monitor glycemic control and lipid management is effective in evaluating the outcomes of care and provides a focused approach that enhances diabetes care. These improvements in metabolic outcomes likely reflect a change in the practice patterns of the physicians as a consequence of using this computerized database system.

Multivariate analyses of elemental hair concentrations from a medieval Nubian population.

Elemental hair concentrations were obtained from 168 mummified individuals recovered during excavations of cementeries S and R (A.D. 550-1450), at Kulubnarti, Republic of the Sudan (Van Gerven et al., 1981). Concentrations of calcium (Ca), magnesium (Mg), strontium (Sr), manganese (Mn), zinc (Zn), iron (Fe), and copper (Cu) were determined using inductively coupled plasma emission spectrometry (ICP) (Sandford, 1984; Sandford et al., 1983). Following univariate statistical reanalyses of these data (Sandford and Kissling, 1993a, b), we applied principal component analysis and multidimensional scaling to clarify their multivariate structure. Similar underlying associations were revealed in the two cemeteries. The first principal component, consisting of Mg, Ca, Sr, and Mn, may reflect inherent chemical similarities coupled with specific dietary factors (e.g., vegetation intakes) and physiological processes (e.g., bone remodeling). The second principal component, a contrast between Fe and Zn, may be due to their competitive relationship during absorption. The third principal component consists of Cu alone (in cemetery S), and Cu and Fe (in cemetery R), suggesting utilization of animal protein and an underlying synergism between Cu and Fe, respectively. Multidimensional scaling substantiates a three-dimensional model for describing elemental covariation. While interpretation of the first two dimensions was analogous to those of the first two principal components, the third dimension may represent antagonism between pairs of elements during absorption, transport and/or utilization (cemetery R: Cu vs. Zn; cemetery S: Cu vs. Zn, Fe vs. Mn). While these results provide the most persuasive evidence to date that elemental hair concentrations from this population reflect chiefly biogenic processes, isolation of diagenetic and exogenous effects requires further investigation through controlled studies.