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The Anniston Community Health Survey, a cross-sectional study, was undertaken in 2005–2007 to study environmental exposure to polychlorinated biphenyl (PCB) and organochlorine (OC) pesticides and health outcomes among residents of Anniston, AL, United States. The examination of potential risks between these pollutants and metabolic syndrome, a cluster of cardiovascular risk factors (i.e., hypertension, central obesity, dyslipidemia and dysglycemia) was the focus of this analysis. Participants were 548 adults who completed the survey and a clinic visit, were free of diabetes, and had a serum sample for clinical laboratory parameters as well as PCB and OC pesticide concentrations. Associations between summed concentrations of 35 PCB congeners and 9 individual pesticides and metabolic syndrome were examined using generalized linear modeling and logistic regression; odds ratios (OR) and 95% confidence intervals (CI) are reported. Pollutants were evaluated as quintiles and as log transformations of continuous serum concentrations. Participants were mostly female (68%) with a mean age (SD) of 53.6 (16.2) years. The racial distribution was 56% white and 44% African American; 49% met the criteria for metabolic syndrome. In unadjusted logistic regression, statistically significant and positive associations across the majority of quintiles were noted for seven individually modeled pesticides (p,p′-DDT, p,p′-DDE, HCB, β-HCCH, oxychlor, tNONA, Mirex). Following adjustment for covariables (i.e., age, sex, race, education, marital status, current smoking, alcohol consumption, positive family history of diabetes or cardiovascular disease, liver disease, BMI), significant elevations in risk were noted for p,p′-DDT across multiple quintiles (range of ORs 1.61 to 2.36), for tNONA (range of ORs 1.62–2.80) and for p,p′-DDE [OR (95% CI)] of 2.73 (1.09–6.88) in the highest quintile relative to the first. Significant trends were observed in adjusted logistic models for log10 HCB [OR=6.15 (1.66–22.88)], log10 oxychlor [OR=2.09 (1.07–4.07)] and log10 tNONA [3.19 (1.45–7.00)]. Summed PCB concentrations were significantly and positively associated with metabolic syndrome only in unadjusted models; adjustment resulted in attenuation of the ORs in both the quintile and log-transformed models. In conclusion, several OC pesticides were found to have significant associations with metabolic syndrome in the Anniston study population while no association was observed for PCBs. Keywords: Metabolic syndrome, Polychlorinated biphenyls, Organochlorine pesticides and herbicides, Insulin resistance, Obesity

Objective To assess the current state of electronic health record (EHR) use by ophthalmologists, including adoption rate, user satisfaction, functionality, benefits, barriers, and knowledge of meaningful use criteria. Design Population-based, cross-sectional study. Participants A total of 492 members of the American Academy of Ophthalmology (AAO). Methods A random sample of 1500 AAO members were selected on the basis of their practice location and solicited to participate in a study of EHR use, practice management, and image management system use. Participants completed the survey via the Internet, phone, or fax. The survey included questions about the adoption of EHRs, available functionality, benefits, barriers, satisfaction, and understanding of meaningful use criteria and health information technology concepts. Main Outcome Measures Current adoption rate of EHRs, user satisfaction, benefits and barriers, and availability of EHR functionality. Results Overall, 32% of the practices surveyed had already implemented an EHR, 15% had implemented an EHR for some of their physicians or were in the process of implementation, and another 31% had plans to do so within 2 years. Among those with an EHR in their practice, 49% were satisfied or extremely satisfied with their system, 42% reported increased or stable overall productivity, 19% reported decreased or stable overall costs, and 55% would recommend an EHR to a fellow ophthalmologist. For those with an electronic image management system, only 15% had all devices integrated, 33% had images directly uploaded into their system, and 12% had electronic association of patient demographics with the image. Conclusions The adoption of EHRs by ophthalmology practices more than doubled from 2007 to 2011. The satisfaction of ophthalmologists with their EHR and their perception of beneficial effects on productivity and costs were all lower in 2011 than in 2007. Knowledge about meaningful use is high, but the percentage of physicians actually receiving incentive payments is relatively low. Given the importance of imaging in ophthalmology, the shortcomings in current image management systems need to be addressed. Financial Disclosure(s) The author(s) have no proprietary or commercial interest in any materials discussed in this article.

Background: Polychlorinated biphenyls (PCBs) manufactured in Anniston, Alabama, from 1929 to 1971 caused significant environmental contamination. The Anniston population remains one of the most highly exposed in the world. Objectives: Reports of increased diabetes in PCB-exposed populations led us to examine possible associations in Anniston residents. Methods: Volunteers (n = 774) from a cross-sectional study of randomly selected households and adults who completed the Anniston Community Health Survey also underwent measurements of height, weight, fasting glucose, lipid, and PCB congener levels and verification of medications. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated to assess the relationships between PCBs and diabetes, adjusting for diabetes risk factors. Participants with prediabetes were excluded from the logistic regression analyses. Results: Participants were 47% African American, 70% female, with a mean age of 54.8 years. The prevalence of diabetes was 27% in the study population, corresponding to an estimated prevalence of 16% for Anniston overall; the PCB body burden of 35 major congeners ranged from 0.11 to 170.42 ppb, wet weight. The adjusted OR comparing the prevalence of diabetes in the fifth versus first quintile of serum PCB was 2.78 (95% CI: 1.00, 7.73), with similar associations estimated for second through fourth quintiles. In participants < 55 years of age, the adjusted OR for diabetes for the highest versus lowest quintile was 4.78 (95% CI: 1.11, 20.6), whereas in those ≥ 55 years of age, we observed no significant associations with PCBs. Elevated diabetes prevalence was observed with a 1 SD increase in log PCB levels in women (OR = 1.52; 95% CI: 1.01, 2.28); a decreased prevalence was observed in men (OR = 0.68; 95% CI: 0.33, 1.41). Conclusions: We observed significant associations between elevated PCB levels and diabetes mostly due to associations in women and in individuals < 55 years of age.

While it has been shown that estradiol treatment accelerates the onset of lupus nephritis with autoantibody production and kidney damage in both male and female lupus-prone mice, the specific mechanism(s) involved are unknown. Our previous work has shown that alterations in IdLNF1-reactive T cells and IdLNF1+ antibodies correlated closely with the onset of autoimmune nephritis in female F1 progeny of SWR and NZB (SNF1) mice, supporting a critical role for the IdLNF1 idiotype in the development of disease. Since male SNF1 mice normally do not develop nephritis, we tested whether administration of 17β-estradiol (E-2) to male SNF1 mice would increase IdLNF1 IgG levels and autoreactive T cells, and further, induce nephritis. We found that E-2-treated male SNF1 mice developed nephritis with the same time course and mean survival as normal female SNF1 mice. Moreover, it appeared that the mechanism involved increased serum IdLNF1+IgG and its deposition in kidney glomeruli, preceded by astriking twofold increase in T-lymphocytes expressing the memory phenotype (CD44+CD45RBlo) predominantly in the IdLNF1-reactive T-cell population. In addition, we noted that cells with this phenotype were increased in the nephritic kidneys of treated mice, suggesting a direct involvement of those cells in the renal pathology. E-2 treatment also induced increased numbers of pathogenic IdLNF1+ antibody-producing B cells and elevated presentation of pathogenic IdLNF1+ peptide. Taken together, these results suggest a mechanism of E-2-induced acceleration of autoimmune disease in lupus-prone mice may involve expansion of autoreactive idiotypic T and B-cell populations.

We here summarize evidence that thymic atrophy induced by 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) can be mediated, at least in part, by damage to extrathymic T-cell precursors in bone marrow and fetal liver. This atrophy induction does not involve apoptotic mechanisms in thymocytes affected by the bcl-2 proto-oncogene. TCDD mediates atrophy induction through its specific receptor (the AhR) and not through effects on the estrogen receptor. Both TCDD and estradiol induce extrathymic T-cell differentiation in the liver. These extrathymic T-cell populations include cells expressing elevated levels of V beta T-cell receptors that are normally deleted in thymic development.

Epidemiologic evidence suggests that prenatal exposure to intact (unfractionated) cigarette smoke (CS) increases the incidence of cancer in the offspring. A toxicology study was carried out to examine the effects and underlying mechanisms of prenatal exposure to mainstream cigarette smoke (MCS) on offspring resistance to tumor challenge and surveillance mechanisms critical for the recognition and destruction of tumors. Pregnant B6C3F1 mice were exposed by inhalation to MCS for 5 days/week (4 h/day from gestational day 4 to parturition). Smoke-induced effects on offspring-host resistance to transplanted tumor cells; natural killer (NK) cell and cytotoxic T-lymphocyte (CTL) activity; cytokine levels; lymphoid organ immune cell subpopulations; and histology-were examined in 5-, 10- and 20-week-old male and female offspring. At a concentration of smoke roughly equivalent to smoking1 pack of cigarettes/day, prenatally exposed male offspring challenged at 5 week of age with EL4 lymphoma cells demonstrated a greater than two-fold increase in tumor incidence (relative to age-/gender-matched air-exposed offspring); tumors in prenatally smoke-exposed pups also grew significantly faster. Cytotoxic T-lymphocyte activity in the smoke-exposed 5- and 10-week-old male pups was significantly less than that of the age- and gender-matched controls. No effects of prenatal CS exposure were observed on offspring NK activity, cytokine levels, lymphoid organ histology, or immune cell subpopulations. Results demonstrated that exposure of pregnant mice to a relevant dose of MCS decreased offspring resistance against transplanted tumor cells and persistently reduced CTL activity in prenatally exposed pups. This study provides biological plausibility for the epidemiologic data indicating that children of mothers who smoke during pregnancy have a greater risk of developing cancer in later life.

Activation of the aryl hydrocarbon receptor (AHR), a basic helix-loop-helix transcription factor, in lymphocytes by the immunosuppressive environmental contaminant 2,3,7,8,-tetrachlorodibenzo-p-dioxin (TCDD) has been shown to cause thymic atrophy in every species studied. We set out to identify the specific hemopoietic cellular populations in which the AHR was activated to lead to thymic atrophy and to determine the effect of AHR activation in those cellular populations. Initially, we examined whether AHR activation in intrathymic dendritic cells could mediate TCDD-induced thymic atrophy. It was found that thymic atrophy occurred only when the AHR could be activated in the thymocytes but not hemopoietic-derived dendritic cells or other APCs. We next analyzed the effect of TCDD on the proliferation of thymocytes in vivo. There was a significant increase in the percentage of thymocytes in the G1 phase of the cell cycle and a significant decrease in the percentage of S plus G2/M thymocytes, especially in the CD4−CD8−CD3− triple-negative intrathymic progenitor cell population 24 h after exposure to 30 μg/kg TCDD. Furthermore, by 12 h after exposure to TCDD, we observed ∼60% reduction of 5-bromo-2′-deoxyuridine incorporation in specific intrathymic progenitor cell populations. This reduction persisted for at least 6 days. These data indicate that intrathymic progenitor cells are direct targets of TCDD in the thymus and suggest that TCDD causes thymic atrophy by reducing entrance into cell cycle in these populations.

So-called coplanar polychlorinated biphenyls (PCBs), as well as other environmental contaminants that are aryl hydrocarbon receptor (AhR) agonists, may compromise the normal functions of vascular endothelial cells by activating oxidative stress-sensitive signaling pathways and subsequent proinflammatory events critical in the pathology of atherosclerosis and cardiovascular disease. To test this hypothesis, porcine endothelial cells were exposed to PCB 153 and to three coplanar PCBs (PCB 77, PCB 126, or PCB 169). In contrast to PCB 153, which is not a ligand for the Ah receptor (AhR), all coplanar PCBs disrupted endothelial barrier function. All coplanar PCBs increased expression of the CYP1A1 gene, oxidative stress (DCF fluorescence), and the DNA-binding activity of nuclear factor kappaB (NF-kappaB). PCB-induced oxidative stress was concentration-dependent, with PCB 126 exhibiting a maximal response at the lowest concentration (0.5 microM) tested. The increase in NF-kappaB-dependent transcriptional activity was confirmed in endothelial cells by a luciferase reporter gene assay. In contrast to PCB 153, coplanar PCBs that are AhR ligands increased endothelial production of interleukin-6. At 3.4 microM, expression of the adhesion molecule VCAM-1 was most sensitive to PCB 77 and 169. We also provide in vivo evidence, suggesting that binding to the AhR is critical for the proinflammatory properties of PCBs. Twenty hours after a single administration of PCB 77, VCAM-1 expression was increased only in wild-type mice, while mice lacking the AhR gene showed no increased staining for VCAM-1. These data provide evidence that coplanar PCBs, agonists for the AhR, and inducers of cytochrome P450 1A1, produce oxidative stress and an inflammatory response in vascular endothelial cells. An intact AhR may be necessary for the observed PCB-induced responses. These findings suggest that activation of the AhR can be an underlying mechanism of atherosclerosis mediated by certain environmental contaminants.

The aryl hydrocarbon receptor (AhR) is a ligand-activated transcription factor that mediates many of the toxic effects induced by exposure to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), a high-affinity AhR ligand and a potent immunotoxicant. AhR-deficient mice have been constructed, and there are reports that the animals display altered splenic architecture and cellularity with an apparent increased incidence of infection. These observations have led to speculation that the immune system of these animals might be compromised, however, their functional immune response has not been directly tested. In the studies presented here, we examined the immune response of two strains of 8- to 10-week-old AhR-deficient mice. Mice were challenged with model antigens, allogeneic P815 tumor cells, or sheep red blood cells, and their ability to generate cell-mediated and humoral immune responses was examined. In addition, to address the obligatory role of the AhR in TCDD-induced immune suppression, we examined the immune response of the AhR-null animals following exposure to an immunosuppressive dose of TCDD. Results from these studies showed that AhR-deficient mice were able to mount normal productive immune responses to both model antigens and that neither the cellular nor the humoral response was suppressed by exposure to TCDD. Interestingly, however, we found that the immune response of heterozygous AhR(+/-) mice was less sensitive to TCDD than homozygous AhR(+/+) mice. The results of these studies suggest that the absence of the AhR does not impact the function of the immune system, but confirm the findings of previous studies that have indicated the AhR plays an obligatory role in TCDD-induced immune suppression.

Both the estrogenic drug diethylstilbestrol (DES) and the pervasive environmental contaminant 2,3,7,8-tetrachlorodibenzo- p -dioxin (TCDD) inhibit thymocyte development. The mechanisms by which either agent induces thymic atrophy are still undetermined. We previously found that TCDD and DES inhibited C57BL/6 murine fetal thymocyte organ cultures (FTOC) at different stages of development. Now, using bcl-2 transgenic (TG) mice, we have further investigated their effects on FTOC proliferation, differentiation, maturation, and apoptosis. As with C57BL/6 mice, thymocyte development in C3H/ bcl-2 FTOCs was inhibited by either TCDD (10 nM) or DES (20 μM) in both bcl-2 TG− and TG+ littermates. However, the percentage reduction of cell number induced by DES in bcl-2 TG+ FTOCs was significantly less than the level of inhibition in TG− FTOCs. There was no difference in the level of reduction from TCDD-exposed TG+ or TG− FTOC. Whereas TCDD increased production of mature CD8 cells in either strain, DES mainly yielded cells in the CD4 − CD8 − (DN) stage in TG− mice. The anti-apoptotic bcl-2 transgene overcame some DES blocking of DN thymocyte development, allowing more cells to differentiate into CD4 single-positive cells. Analysis of cell cycle showed that TCDD inhibited entry into S phase, whereas DES blocked cell cycling in the G2/M phase. TCDD did not induce detectable apoptosis in FTOC. However, unlike the effects of 17β-estradiol (E2) in vivo, DES induced apoptosis in the TG− FTOC, and these apoptotic cells were mainly in the DN subpopulation. This apoptosis could be prevented by the overexpression of bcl-2 in the TG+ mice. Our results demonstrate that, in addition to inhibition of fetal thymocytes at different stages of development by TCDD and DES, DES also induces thymic atrophy by both bcl-2 -inhibitable apoptosis and by inducing cell cycle arrest in G2/M in the latest stage in the stem cell compartment. TCDD, on the other hand, does not induce apoptosis, but inhibits entry into cell cycle in the earliest stage in the stem cell compartment.

Although estrogens and estrogen receptors (ERs) are known to function in the male brain and reproductive tract, few studies have evaluated their involvement in the male hematopoietic and immune systems. This study was undertaken to determine the role of ERalpha in hematopoietic progenitor and B lymphocyte maturation. ERalpha knockout (ER-/-), wild-type (ER+/+), and radiation chimeric (ERalpha positive or negative in either nonhematopoietic or hematopoietic elements, or both) male mice were used to determine target tissues. ER-/- and ER+/+ animals showed similar hematopoietic progenitor profiles, but the ER-/- animals had fewer cells in all bone marrow B lymphocyte subpopulations. Animals receiving a pharmacological dose (5 mg/kg BW) of 17beta-estradiol (E2) with both elements, ER+/+, had decreased early hematopoietic progenitors and a shift toward a mature B cell subpopulation, whereas animals with both elements, ER-/-, showed changes only in early hematopoietic progenitors. Hematopoietic element ER+/+ animals exhibited greater E2-induced hematopoietic progenitor and B lymphocyte alterations than those having only nonhematopoietic ERalpha. These data indicate that 1) ERalpha is not necessary for regulating male mouse normal hematopoietic progenitor cell proportions, but is involved in B cell regulation; and 2) ERalpha in hematopoietic elements is predominantly responsible for mediating E2-induced hematopoietic and B cell changes.

This laboratory has studied a number of flavone derivatives for aryl hydrocarbon receptor (AhR) agonist and antagonist potential using cell-free and cell culture systems. The current report extends these investigations by testing the potent AhR antagonist 3′-methoxy-4′-nitroflavone (3′M4′NF) for in vivo activity. Wild-type C57Bl/6 male mice were treated with solvent, benzo[ a ]pyrene (B[ a ]P; 150 mg/kg), or concurrently with B[ a ]P and 3′M4′NF (60 mg/kg; delivered as a split dose). Since B[ a ]P is bioactivated to genotoxic metabolites by AhR-regulated enzymes, we measured B[ a ]P-induced chromosomal damage in peripheral blood (i.e. micronuclei) to characterize the antagonistic potential of 3′M4′NF in vivo . The influence of AhR signal transduction was investigated further by challenging wild-type and Ahr null allele mice with B[ a ]P with and without a 3′M4′NF co-treatment. The micronucleus data obtained from these experiments indicated that 3′M4′NF can attenuate the genotoxicity of B[ a ]P significantly. Since 3′M4′NF also protected Ahr null allele mice from B[ a ]P-induced genetic damage, it was apparent that AhR-independent mechanisms contribute to the effects observed. However, as opposed to the protective effects observed with the micronucleus endpoint, histological observations and lethality data indicated that some B[ a ]P effects are enhanced by 3′M4′NF. Potentiated B[ a ]P toxicity may be explained by inhibition of basal and induced CYP1A1/2 activities. Both in vitro and in vivo data presented herein support this hypothesis.

The ligand-activated aryl hydrocarbon receptor (AHR) is a cytosolic DNA binding protein. Although no biologic role for AHR has been elucidated, it mediates the immunotoxicity of xenobiotics such as 2,3,7,8-tetrachlorodibenzo- p -dioxin (TCDD), and its targeted inactivation produces abnormal immune system development. While investigators have demonstrated AHR's involvement in TCDD-induced B lymphocyte functional alterations, little is known about the receptor's possible role in early B cell maturation and whether exogenous ligands change this process. The purpose of this study was to determine, (1) whether bone marrow B lymphocyte maturation is affected by AHR presence, (2) if so, its relative importance in hematopoietic and/or nonhematopoietic elements and, (3) whether TCDD alters this process. Radiation chimeras were produced that were AHR positive ( Ahr +/+) or negative ( Ahr −/−) in either their nonhematopoietic or hematopoietic elements, or both. Marrow cells were analyzed for alterations in B lymphocyte maturation stage cell numbers in both vehicle- and TCDD-treated animals. Our results showed that (1) Ahr −/− animals had significantly higher numbers of pro/pre-B cells than Ahr +/+ animals, (2) TCDD treatment of Ahr +/+ animals produced a decrease in pro/pre-B cell numbers, whereas no effect was observed on Ahr −/− animals, and (3) AHR is required in both hematopoietic and stromal elements for maintenance of B cell subset maturation profiles.

Summary: The cardiac neural crest (CNC) plays a central role in development of the thymus gland and cardiovascular system. Through morphological and histological characterization of embryos homozygous for the Del(7)Tyrc-112K and Del(7)Tyrc-3H albino deletions, we identified abnormalities that are consistent with aberrant development of tissues requiring CNC contributions. The defects include incompletely penetrant heart and great vessel patterning defects and hypoplastic thymus glands. The CNC phenotype is complemented by the partially overlapping deletion Del(7)Tyrc-23DVT. Combined, these results suggest that a functional region necessary for development of CNC derived tissues is located between the Del(7)Tyrc-23DVT and Del(7)Tyrc-112K distal deletion breakpoints. This interval encompasses a functional region previously identified as important for juvenile survival (juvenile development and fertility, jdf). Using deletion mapping, we localized the Frizzled4 (Fzd4) gene to the jdf/thymus and cardiac development intervals. genesis 27:64–75, 2000. © 2000 Wiley-Liss, Inc.

Estrogens affect the development, maturation, and function of multiple organ systems, including the immune system. One of the main targets of estrogens in the immune system is the thymus, which undergoes atrophy and phenotypic alterations when exposed to elevated levels of estrogen. To determine how estrogens influence the thymus and affect T cell development, estrogen receptor α (ERα) knockout (ERKO) mice were examined. ERKO mice have significantly smaller thymi than their wild-type (WT) littermates. Construction of ER radiation bone marrow chimeras indicated that the smaller thymi were due to a lack of ERα in radiation-resistant tissues rather than hemopoietic elements. ERKO mice were also susceptible to estradiol-induced thymic atrophy, but the extent of their atrophy was less than what was seen in WT mice. The estradiol-treated ERKO mice failed, however, to manifest alterations in their thymic CD4/CD8 phenotypes compared with WT mice. Therefore, ERα is essential in nonhemopoietic cells to obtain a full-sized thymus, and ERα also mediates some of the response of the thymus to elevated estrogen levels. Finally, these results suggest that in addition to ERα, another receptor pathway is involved in estradiol-induced thymic atrophy.

Pathologic changes associated with 2,3,7, 8-tetrachlorodibenzo-p-dioxin (TCDD) exposure have been reported in the livers of a wide range of species. While these changes have been extensively described, the mechanisms of toxic interaction(s) that produce these lesions remain unclear. Using an aryl hydrocarbon receptor (Ahr) knockout male mouse chimeric model, we investigated whether the presence of this receptor in hematopoietic and/or parenchymal cells affects TCDD-induced hepatotoxicity. Bone marrow chimeras were produced by hematopoietic reconstitution of irradiated mice. Specifically, chimeras were generated with aryl hydrocarbon receptor (AHR) positive hematopoietic and parenchymal cells (Ahr+/+ animal bone marrow cells into irradiated Ahr+/+ animals), AHR positive hematopoietic and negative parenchymal cells (Ahr+/+ into Ahr-/-), AHR negative hematopoietic and positive parenchymal cells (Ahr-/- into Ahr+/+), and AHR negative hematopoietic and parenchymal cells (Ahr-/- into Ahr-/-). Male wild-type (Ahr+/+) and knockout (Ahr-/-) animals were used as nonchimeric controls. Following TCDD treatment (30 microg/kg body wt), liver sections from mice in each control and chimeric group were histologically evaluated for necrotic and inflammatory changes. TCDD treatment produced moderate inflammation in Ahr+/+ controls and Ahr+/+ into Ahr+/+ chimeras. This response was mild in TCDD-treated Ahr-/-, Ahr-/- into Ahr-/-, Ahr+/+ into Ahr-/-, and Ahr-/- into Ahr+/+ animals and was not different from the corresponding vehicle-treated groups. Moderate necrosis was observed in all TCDD-treated controls or chimeras with AHR-positive parenchyma. No or mild necrosis was observed in TCDD- and vehicle-treated animals containing AHR-negative parenchyma. These data indicate that the presence of AHR in hepatic parenchyma alone is sufficient for TCDD induction of hepatic necrosis, and its presence in hematopoietic cells is necessary for the inflammatory response to TCDD-induced hepatic lesions.

PURPOSE: To investigate the efficacy and safety of ketorolac tromethamine 0.5% ophthalmic solution (Acular; Allergan, Inc, Irvine, California) in the treatment of moderate to severe anterior segment inflammation developing after unilateral cataract surgery with intraocular lens implantation. METHODS: Only patients who exhibited moderate or greater levels of cells and flare 1 day after surgery were included in this multicenter, double-masked, randomly assigned, parallel-group study. Topical ketorolac or vehicle solution (Allergan, Inc) was administered to the treated eye four times daily, starting the day after surgery and continuing for 14 days. RESULTS: Ketorolac was significantly more effective than the vehicle solution in reducing anterior chamber cells ( P ≤ .030) and flare ( P ≤ .025), conjunctival erythema ( P ≤ .046), ciliary flush ( P ≤ .006), tearing ( P ≤ .012), photophobia ( P ≤ .014), and pain ( P ≤ .049). Half as many patients from the ketorolac group (14/51) were discontinued from the study for lack of efficacy, compared with the vehicle group (28/51; P = .005). There was no significant difference between ketorolac and the vehicle solution in changes in visual acuity, intraocular pressure, biomicroscopic or ophthalmoscopic variables, or adverse events. CONCLUSIONS: Ketorolac tromethamine 0.5% ophthalmic solution is safe and provides substantial anti-inflammatory activity in the treatment of moderate to severe anterior segment inflammation developing after cataract surgery and intraocular lens implantation.

Background Nutrition and lifestyle are well-defined modulators of chronic diseases. Poor dietary habits (such as high intake of processed foods rich in fat and low intake of fruits and vegetables), as well as a sedentary lifestyle clearly contribute to today’s compromised quality of life in the United States. It is becoming increasingly clear that nutrition can modulate the toxicity of environmental pollutants. Objectives Our goal in this commentary is to discuss the recommendation that nutrition should be considered a necessary variable in the study of human disease associated with exposure to environmental pollutants. Discussion Certain diets can contribute to compromised health by being a source of exposure to environmental toxic pollutants. Many of these pollutants are fat soluble, and thus fatty foods often contain higher levels of persistent organics than does vegetable matter. Nutrition can dictate the lipid milieu, oxidative stress, and antioxidant status within cells. The modulation of these parameters by an individual’s nutritional status may have profound affects on biological processes, and in turn influence the effects of environmental pollutants to cause disease or dysfunction. For example, potential adverse health effects associated with exposure to polychlorinated biphenyls may increase as a result of ingestion of certain dietary fats, whereas ingestion of fruits and vegetables, rich in antioxidant and anti-inflammatory nutrients or bioactive compounds, may provide protection. Conclusions We recommend that future directions in environmental health research explore this nutritional paradigm that incorporates a consideration of the relationships between nutrition and lifestyle, exposure to environmental toxicants, and disease. Nutritional interventions may provide the most sensible means to develop primary prevention strategies of diseases associated with many environmental toxic insults.

The role of aromatic hydrocarbon receptor (AhR)-mediated events on the genotoxicity of mainstream cigarette smoke condensate was investigated. In vitro studies with mouse hepatoma cells stably transfected with a DRE-dependent luciferase reporter indicate that cigarette smoke condensate is able to transform AhR to an active form which is capable of initiating gene transcription. Micronucleus formation in two hepatoma cell lines was used as an index of genotoxicity. Cigarette smoke condensate was observed to induce a higher frequency of micronuclei in Hepa1c1c7 cells relative to TAOc1BP(r)c1 cells, which express approximately 10-fold less AhR. Furthermore, the frequency of micronuclei was potentiated when Hepa1c1c7 cells were pretreated with 2,3,7,8-tetrachlorodibenzo-p-dioxin, a high affinity ligand of AhR. These in vitro studies were followed by an in vivo experiment with Ahr+/+ and Ahr-/- mice. Animals were dosed for three consecutive days with cigarette smoke condensate (0.5-10 microg/kg/day, i.p. injection). The frequency of micronuclei in reticulocytes and total erythrocytes was determined in peripheral blood samples collected 24 h after the last administration. While condensate was found to increase the incidence of micronucleated reticulocytes in Ahr+/+ mice, no increase was observed in the null allele animals. Furthermore, the frequency of micronucleated erythrocytes, a measure of basal chromosome-damaging activity, was slightly but significantly higher in Ahr+/+ relative to Ahr-/- mice. Together, these data suggest that cigarette smoke contains chemicals which transform the AhR to an active transcription factor and AhR-regulated enzyme induction plays an important role in mediating the genotoxicity of this complex environmental pollutant.

Dexamethasone (Dex), estradiol (E2), and 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) all affect the immune system, causing immunosuppression and thymic atrophy. It is still uncertain how and where these compounds act to induce thymic atrophy. However, it has been suggested that these compounds may have similar actions and targets, i.e., apoptosis of immature thymocytes for Dex and TCDD and preferential targeting of double-positive cells by Dex and E2. Thelckpr-bcl-2 transgenic mouse has been shown to be protected against Dex-induced thymic atrophy. We used this murine model to determine if bcl-2 expression would also protect against E2- and TCDD-induced thymic atrophy. Our results indicate that, although the bcl-2 transgenic (TG+) mice were fully protected from atrophy induced by a single dose of Dex, atrophy was still induced in these mice following treatment with E2 or TCDD. Phenotypic analysis of thymocytes from TG− and TG+ mice also showed distinct consequences of atrophy induced by Dex, E2, and TCDD. Finally, since there are alternative pathways for apoptosis that are bcl-2 independent, both TG− and TG+ thymocytes were examined directly for indications of apoptosis using the TUNEL assay. After TCDD and E2 treatment there were no detectable signs of apoptosis in either TG− or TG+ mice even at early time points and at elevated dose levels. These results indicate that there are distinct mechanisms for the actions of Dex, E2, and TCDD in the thymus and that apoptosis is not a key mechanism of E2- and TCDD-induced thymic atrophy.

2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) and related congeners affect the immune system, causing immunosuppression and thymic atrophy in a variety of animal species. TCDD is believed to exert its effects primarily through the ligand-activated transcription factor, the aryl hydrocarbon receptor (AhR). Although the AhR is found at high levels in both thymocytes and thymic stroma, it is uncertain in which cells TCDD is activating the AhR to cause alterations in the thymus. Some investigators have suggested that stromal elements, primarily epithelial cells, within the thymus are the primary targets for TCDD. Others have suggested that atrophy is due to a direct effect on thymocytes, either by apoptosis or by altering the development of progenitor cells. By producing chimeric mice with TCDD-responsive (AhR+/+) stromal components and TCDD-unresponsive (AhR−/−) hemopoietic components, or the reverse, we have clarified the role of stromal vs hemopoietic elements in TCDD-induced thymic alterations. Our results show that the targets for TCDD-induced thymic atrophy and phenotypic alterations are strictly in the hemopoietic compartment and that TCDD activation of epithelial cells in the stroma is not required for thymic alterations. Furthermore, changes observed in the putative stem cell populations of these chimeric mice are also dependent on TCDD activation of the AhR in hemopoietic elements.

The aryl hydrocarbon receptor (AHR) binds to environmental toxicants including synthetic halogenated aromatic hydrocarbons and is involved in a diverse array of biological processes. Recently, the AHR was shown to control host immunity by affecting the balance between inflammatory T cells that produce IL-17 (Th17) and IL-22 versus regulatory T cells (Treg) involved in tolerance. While environmental AHR ligands can mediate this effect, endogenous ligands are likely to be more relevant in host immune responses. We investigated downstream metabolites of tryptophan as potential AHR ligands because (1) tryptophan metabolites have been implicated in regulating the balance between Th17 and Treg cells and (2) many of the AHR ligands identified thus far are derivatives of tryptophan. We characterized the ability of tryptophan metabolites to bind and activate the AHR and to increase IL-22 production in human T cells. We report that the tryptophan metabolite, cinnabarinic acid (CA), is an AHR ligand that stimulates the differentiation of human and mouse T cells producing IL-22. We compare the IL-22-stimulating activity of CA to that of other tryptophan metabolites and define stimulation conditions that lead to CA production from immune cells. Our findings link tryptophan metabolism to AHR activation and define a novel endogenous AHR agonist with potentially broad biological functions.

Epidemiological studies suggest that maternal smoking increases the incidence in the progeny of certain childhood cancers. Our previous study in mice demonstrated the feasibility of such an association by demonstrating that prenatal exposure to cigarette smoke (CS) elevated the incidence of transplanted tumors and reduced cytotoxic T-lymphocyte (CTL) activity in juvenile male offspring. The current study extends these findings by investigating the relationship between CS-induced CTL suppression and effects on regulators of effector T-cell activity, such as T-regulatory (Treg; CD4+ CD25+ Foxp3+) cells and transforming growth factor (TGF)-β. Results here demonstrate that in utero exposure to CS, at a maternal particle concentration of 15 mg/m3 (4 h/d, 5 d/wk), significantly reduced ex vivo CTL activity of whole splenocytes (and isolated CD8+ cells) against tumor cells both before and after injection of prenatally exposed mice with EL4 lymphoma cells. In contrast, prenatal CS exposure significantly increased levels of thymic Treg cells in a time-dependent manner following tumor cell injection. In vitro production of TGF-β by splenocytes recovered from prenatally exposed, tumor-bearing mice was also altered. Neither prenatal CS exposure nor subsequent administration of EL4 cells exerted any marked effects on lymphoid organ weights, cellularity, or histologic profiles. Given that Treg cells and TGF-β suppress effector T-cell activities, these findings suggest possible immune mechanisms by which early exposure to CS reduces CTL tumoricidal activity during tumor cell development. Data suggest that children of smoking mothers may be less able to mount an appropriate adaptive immune response to tumors, thus increasing their risk for some cancers later in life.

To assess the current state of electronic health record (EHR) use by ophthalmologists, including adoption rate, user satisfaction, functionality, benefits, barriers, and knowledge of meaningful use criteria.Population-based, cross-sectional study.A total of 492 members of the American Academy of Ophthalmology (AAO).A random sample of 1500 AAO members were selected on the basis of their practice location and solicited to participate in a study of EHR use, practice management, and image management system use. Participants completed the survey via the Internet, phone, or fax. The survey included questions about the adoption of EHRs, available functionality, benefits, barriers, satisfaction, and understanding of meaningful use criteria and health information technology concepts.Current adoption rate of EHRs, user satisfaction, benefits and barriers, and availability of EHR functionality.Overall, 32% of the practices surveyed had already implemented an EHR, 15% had implemented an EHR for some of their physicians or were in the process of implementation, and another 31% had plans to do so within 2 years. Among those with an EHR in their practice, 49% were satisfied or extremely satisfied with their system, 42% reported increased or stable overall productivity, 19% reported decreased or stable overall costs, and 55% would recommend an EHR to a fellow ophthalmologist. For those with an electronic image management system, only 15% had all devices integrated, 33% had images directly uploaded into their system, and 12% had electronic association of patient demographics with the image.The adoption of EHRs by ophthalmology practices more than doubled from 2007 to 2011. The satisfaction of ophthalmologists with their EHR and their perception of beneficial effects on productivity and costs were all lower in 2011 than in 2007. Knowledge about meaningful use is high, but the percentage of physicians actually receiving incentive payments is relatively low. Given the importance of imaging in ophthalmology, the shortcomings in current image management systems need to be addressed.The author(s) have no proprietary or commercial interest in any materials discussed in this article.

Lymphangioleiomyomatosis (LAM) is a rare disease affecting women, classically involving the lungs. However, extrapulmonary manifestations also occur, including renal angiomyolipomas, retroperitoneal lymphangioleiomyomas and extrathoracic lymphadenopathy. The lung disease is hormone-responsive, but no information exists regarding sex hormone responsiveness of abdominal LAM. Here, we report two women with LAM whose abdominal lymphangioleiomyomas increased in size with hormonal changes of the menstrual cycle. This is the first description of abdominal lymphangioleiomyomas exhibiting hormone responsiveness in LAM. We describe these cases and summarize the literature on abdominal LAM. Menstrual cycle variation should be taken into account when assessing response to therapy, both clinically and in research studies.

While it has been shown that estradiol treatment accelerates the onset of lupus nephritis with autoantibody production and kidney damage in both male and female lupus-prone mice, the specific mechanism(s) involved are unknown. Our previous work has shown that alterations in Id(LN)F(1)-reactive T cells and Id(LN)F(1)+ antibodies correlated closely with the onset of autoimmune nephritis in female F(1) progeny of SWR and NZB (SNF(1)) mice, supporting a critical role for the Id(LN)F(1) idiotype in the development of disease. Since male SNF(1) mice normally do not develop nephritis, we tested whether administration of 17β-estradiol (E-2) to male SNF(1) mice would increase Id(LN)F(1) IgG levels and autoreactive T cells, and further, induce nephritis. We found that E-2-treated male SNF(1) mice developed nephritis with the same time course and mean survival as normal female SNF(1) mice. Moreover, it appeared that the mechanism involved increased serum Id(LN)F(1)(+)IgG and its deposition in kidney glomeruli, preceded by a striking twofold increase in T-lymphocytes expressing the memory phenotype (CD44(+)CD45RB(lo)) predominantly in the Id(LN)F(1)-reactive T-cell population. In addition, we noted that cells with this phenotype were increased in the nephritic kidneys of treated mice, suggesting a direct involvement of those cells in the renal pathology. E-2 treatment also induced increased numbers of pathogenic Id(LN)F(1)+ antibody-producing B cells and elevated presentation of pathogenic Id(LN)F(1)+ peptide. Taken together, these results suggest a mechanism of E-2-induced acceleration of autoimmune disease in lupus-prone mice may involve expansion of autoreactive idiotypic T and B-cell populations.

A single dose of either 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) (10–30 μg/kg), β-estradiol (75mg/kg), or cortisone acetate (150mg/kg) can cause more than 70% thymic atrophy in BALB/cJ mice. However, the kinetics of atrophy and its persistence with estrogen or TCDD is different than that caused by cortisone acetate. Even more striking differences between these agents are seen in the loss and subsequent recovery of terminal deoxynucleotidyl transferase (TdT) synthesizing cells in thymus, and bone marrow. These results and others suggest that, unlike cortisone, TCDD and estradiol cause a more persistent thymic atrophy mostly through alteration or ablation of thymic stem cells.

We evaluated the prophylactic effect of 1% apraclonidine HCl in controlling the increase in intraocular pressure after Nd:YAG posterior capsulotomy in a large, multicenter double-masked clinical trial. One hundred sixty-four patients were enrolled into the apraclonidine-treated group, and 165 into the vehicle-treated group. The incidence of increase in intraocular pressure (greater than 5 mm Hg) in the apraclonidine-treated group (7%, 11 of 163 patients) was significantly less than that in the vehicle-treated group (39%, 64 of 164 patients). Similarly, the mean maximal change in intraocular pressure in the apraclonidine-treated group (1.3-mm Hg decrease) was significantly different from the increase in the vehicle-treated group (5.3-mm Hg increase). Few adverse reactions were observed. The risk for significant loss of visual function after Nd:YAG laser posterior capsulotomy, combined with the efficacy and relative safety of prophylactic apraclonidine, suggest its addition to the treatment armamentarium.

Estrogens play an important role in prostatic development, health, and disease. While estrogen signaling is essential for normal postnatal prostate development, little is known about its prenatal role in control animals. We tested the hypothesis that estrogen signaling is needed for normal male prostatic bud patterning. Budding patterns were examined by scanning electron microscopy of urogenital sinus epithelium from wild-type mice, mice lacking estrogen receptor (ER)alpha, ERbeta, or both, and wild-type mice exposed to the antiestrogen ICI 182,780. Budding phenotypes did not detectably differ among any of these groups, strongly suggesting that estrogen signaling is not needed to establish the prototypical prostatic budding pattern seen in control males. This finding contributes to our understanding of the effects of low-level estrogen exposure on early prostate development. In utero exposure to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) can greatly alter the pattern in which prostatic buds form and reduce their number. For several reasons, including a prior observation that inhibitory effects of TCDD on prostatic budding in rats depend heavily on the sex of adjacent fetuses, we tested the hypothesis that estrogen signaling is needed for TCDD to disrupt prostatic budding. However, budding did not detectably differ among wild-type mice, or mice lacking ERalpha, ERbeta, or both, that were exposed prenatally to TCDD (5 microg/kg on embryonic day 13.5). Nor did ICI 182,780 detectably affect the response to TCDD. These results strongly suggest that estrogen signaling is not needed for TCDD to inhibit prostatic epithelial budding.

In order to investigate the roles of ER subtypes in the estrogen-induced lupus phenotype, ERalpha-deficient (ERalpha(-/-)) and wild-type mice (WT) were injected monthly with estradiol (E-2) starting at 8 weeks. In WT mice, E-2 treatment induced a lupus phenotype, with accelerated death and increased kidney damage, as well as Th2-type serum cytokine and autoantibody production. In contrast, only minimal changes were observed in ERalpha(-/-) mice after E-2 treatment. In a separate study, we found that in immune cells of autoimmune-prone SNF(1) and non-autoimmune DBF(1) mice, both ERalpha and ERbeta were differentially expressed and modulated by E-2. In SNF(1) mice, there were more CD4(+) and CD8(+) T cells constitutively expressing ERalpha, and the percentages of ERalpha+ dendritic cells and macrophages were increased after E-2 exposure compared to DBF(1) mice. Taken together, these observations strongly suggest a role for ERalpha in E-2-induced development of the lupus phenotype.

In a three-month, double-masked, randomized clinical trial, we evaluated the once-daily ocular hypotensive efficacy of 0.25% levobunolol and 0.25% timolol in 80 patients with open-angle glaucoma or ocular hypertension. Thirty-seven of the 39 patients (95%) in the 0.25% levobunolol group and 35 of the 41 patients (85%) in the 0.25% timolol group successfully completed the three-month study period. The overall mean decrease in intraocular pressure was 5.3 mm Hg (22%) in the 0.25% levobunolol group and 5.4 mm Hg (22%) in the 0.25% timolol group. This difference was not statistically significant. In both treatment groups, effects on mean heart rate and blood pressure were minimal. The data suggest that levobunolol 0.25% and timolol 0.25%, administered once daily, are equally effective in the treatment of open-angle glaucoma and ocular hypertension.

Exposure of experimental animals to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) results in severe thymic atrophy and suppression of cell-mediated and humoral immune functions. However, despite much effort the mechanism by which TCDD produces these responses, particularly thymic atrophy, remains unclear. In this report, we have examined the effect of acute TCDD exposure on lymphocyte stem cells in young adult BALB/c mice to determine whether alterations to events early in T lymphopoiesis contribute to TCDD-induced thymic atrophy. TCDD produced a dose-dependent reduction in thymic weight and cellularity following a single dose of 5 to 120 micrograms TCDD/kg. This thymic atrophy correlated with a dose-dependent suppression of the biosynthesis and mRNA levels of the lymphocyte stem cell-specific DNA polymerase terminal deoxynucleotidyl transferase in bone marrow and thymus. However, the reduction in thymic terminal deoxynucleotidyl nucleotidyl transferase synthesis, on a per cell basis, was less than that observed in bone marrow. Intrathymic CD4/CD8 and IL-2R expression demonstrated only mild alterations after exposure to 30 micrograms TCDD/kg. These data suggest that thymocytes are more refractory to TCDD than are pre-T cells. To assess this possibility directly, bone marrow prothymocytes from TCDD-treated donor mice were examined for their capacity to reconstitute the thymuses of adoptive, irradiated recipients. Our results indicate that prothymocyte activity was severely impaired by TCDD exposure and that this effect occurred at low tissue levels of TCDD. In contrast, we observed no reduction in the number of colony-forming unit-granulocyte macrophage and a moderate decrease in colony-forming unit-spleen. These data suggest that TCDD-induced thymic atrophy is the result, at least in part, of impaired thymic seeding by prothymocytes.

We have quantified the emergence of early chromatin breaks during the signal transduction phase of apoptosis in mouse thymocytes after treatment with either ionizing radiation or dexamethasone. Dexamethasone at 1 microM can induce significant levels of DNA breaks (equivalent to the amount induced directly by 7.5 Gy ionizing radiation) within 0.5 h of treatment. The execution phase of apoptosis was not observed until 4-6 h after the same treatment. The presence of the Bcl2 transgene under the control of the p56lck promoter almost completely inhibited apoptosis up to 24 h after treatment, but it had virtually no effect on the early chromatin cleavage occurring in the first 6 h. Ionizing radiation induced chromatin cleavage both directly by damaging DNA and indirectly with kinetics similar to the induction of chromatin cleavage by dexamethasone. The presence of the Bcl2 transgene had no effect on the direct or indirect radiation-induced cleavage in the first 6 h, but after the first 6 h, the Bcl2 gene inhibited further radiation-induced chromatin cleavage. These results suggest that endonucleases are activated within minutes of treatment with either dexamethasone or ionizing radiation as part of the very early signal transduction phase of apoptosis, and prior to the irreversible commitment to cell death.

The aryl hydrocarbon receptor (AhR), a ligand activated transcription factor, is the receptor for the polycyclic aromatic hydrocarbons found in tobacco smoke, polychlorinated biphenyls, and the environmental pollutant, dioxin. To better understand the role of the AhR in the heart, echocardiography, invasive measurements of aortic and left ventricular pressures, isolated working heart preparations, as well as morphological and molecular analysis were used to investigate the impact of AhR inactivation on the mouse heart using the AhR knockout as a model. Cardiac hypertrophy is an early phenotypic manifestation of the AhR knockout. Although the knockout animals were not hypertensive at the ages examined, cardiomyopathy accompanied by diminished cardiac output developed. Despite the structural left ventricular remodeling, the hearts of these animals exhibit minimal fibrosis and do not have the expected increases in surrogate molecular markers of cardiac hypertrophy. The anatomic remodeling without typical features of molecular remodeling is not consistent with hypertrophic growth secondary to pressure or volume overload, suggesting that increased cardiomyocyte size may be a direct consequence of the absence of the AhR in this cell type.

It is well established that dioxins cause a variety of toxic effects and syndromes including alterations of lymphocyte development. Exposure to the prototypical dioxin, 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) leads to severe thymic atrophy in all species studied. It has been shown that most of this toxicity is due to TCDD binding to and activating the aryl hydrocarbon receptor (AHR). Upon activation, the AHR enters the nucleus, dimerizes with the AHR nuclear translocator (ARNT), and this heterodimer modulates a number of genes that mediate toxicity. The AHR and ARNT are members of the basic-helix-loop-helix-Per, ARNT, and Sim homology (bHLH-PAS) family of transcription factors. In this study, we wanted to determine if another bHLH-PAS transcription factor, ARNT2, which has high amino acid sequence identity to ARNT and has been shown to dimerize with the TCDD-activated AHR, is involved in mediating TCDD's effect on lymphocyte development. We determined by RT-PCR that ARNT2 is expressed at a low level in whole thymus, thymocytes, and bone marrow lymphocytes. We created hemopoietic chimeras by lethally irradiating C57BL/6 mice and reconstituting them with fetal liver stem cells that either have or are deficient in a portion of chromosome 7 that contains ARNT2. Regardless of whether chimeras possessed or lacked this chromosome fragment, equal sensitivity to TCDD-induced thymic atrophy was observed despite expression of ARNT2 in the thymus. Furthermore, the absence of ARNT2 (or any other genes found on this portion of chromosome 7) did not confer any protection against TCDD-induced alterations in bone marrow B-cell subsets. These data indicate that in this model system the effects of TCDD-induced thymic atrophy and alterations in B-cell maturation are not dependent on an AHR-ARNT2 heterodimer.

2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD), a ligand for the ubiquitous, intracellular aryl hydrocarbon receptor (AhR), up-regulates the actin-modulating protein adseverin in mouse lymphoid tissues, a response that may be correlated to the immunotoxicity of TCDD. Here, by using chimeric mice with TCDD-responsive (AhR(+/+)) hematopoietic cells and TCDD-unresponsive (AhR(minus sign/minus sign)) thymic stroma, or the reverse, we show that TCDD-induced expression of adseverin in thymus is dependent on AhR expression in hematopoietic cells but not in stroma. The use of fetal thymic organ cultures also indicates that TCDD-induced expression of adseverin is confined to the thymocytes. The thymic stroma showed no induction of adseverin expression after TCDD exposure, although TCDD clearly activated the AhR in these cells, as indicated by the induction of CYP1A1. Adseverin was not induced in the thymus of normal adult C57BL/6 mice exposed to beta-estradiol or dexamethasone, two other agents, which also cause thymic atrophy. This further supports that adseverin induction is a specific gene regulatory effect by TCDD on thymocytes.

This laboratory has previously reported data suggesting that aryl hydrocarbon receptor (AhR) signaling may have a net potentiating effect on the DNA damaging potential of cigarette smoke. The experiments described in this report extend these studies by testing whether the potent AhR antagonist 3'-methoxy-4'-nitroflavone (3'M4'NF) can modify the in vivo genetic toxicity of benzo[a]pyrene (B[a]P) and the complex mixture of chemicals in cigarette smoke condensate (CSC). Initial experiments were designed to determine 3'M4'NF doses which can antagonize AhR in vivo but which have little effect on constitutive cytochrome P4501A (CYP1A) activity. These experiments took three forms: (i) zoxazolamine paralysis tests, a functional assay of cytochrome P450 CYP1A activity in 3'M4'NF-treated C57Bl/6J mice; (ii) co-treatment of AHR: null allele mice with 150 mg/kg B[a]P plus a range of 3'M4'NF concentrations in order to evaluate the potential of the flavone to interact with non-AhR targets which may affect B[a]P toxicity; (iii) an evaluation of the in vivo AhR antagonist activity of 3'M4'NF using transgenic mice which carry a dioxin-responsive element-regulated lacZ reporter. Once an appropriate dose range was determined, C57Bl/6J mice were challenged with B[a]P or CSC with and without 3'M4'NF co-treatment. Chromosome damage was measured by scoring the frequency of micronuclei in peripheral blood reticulocytes. Data presented herein suggest that 3'M4'NF can protect mice from B[a]P-induced bone marrow cytotoxicity and genotoxicity. Furthermore, CSC-associated genotoxicity was abolished by the flavonoid. These data add support to our hypothesis that AhR signaling has a net potentiating effect on the genetic toxicity and, presumably, carcinogenicity of cigarette smoke.

The cardiac neural crest (CNC) plays a central role in development of the thymus gland and cardiovascular system. Through morphological and histological characterization of embryos homozygous for the Del(7)Tyr(c-112K) and Del(7)Tyr(c-3H) albino deletions, we identified abnormalities that are consistent with aberrant development of tissues requiring CNC contributions. The defects include incompletely penetrant heart and great vessel patterning defects and hypoplastic thymus glands. The CNC phenotype is complemented by the partially overlapping deletion Del(7)Tyr(c-23DVT). Combined, these results suggest that a functional region necessary for development of CNC derived tissues is located between the Del(7)Tyr(c-23DVT) and Del(7)Tyr(c-112K) distal deletion breakpoints. This interval encompasses a functional region previously identified as important for juvenile survival (juvenile development and fertility, jdf). Using deletion mapping, we localized the Frizzled4 (Fzd4) gene to the jdf/thymus and cardiac development intervals.

Although estrogens and estrogen receptors (ERs) are known to function in the male brain and reproductive tract, few studies have evaluated their involvement in the male hematopoietic and immune systems. This study was undertaken to determine the role of ERalpha in hematopoietic progenitor and B lymphocyte maturation. ERalpha knockout (ER-/-), wild-type (ER+/+), and radiation chimeric (ERalpha positive or negative in either nonhematopoietic or hematopoietic elements, or both) male mice were used to determine target tissues. ER-/- and ER+/+ animals showed similar hematopoietic progenitor profiles, but the ER-/- animals had fewer cells in all bone marrow B lymphocyte subpopulations. Animals receiving a pharmacological dose (5 mg/kg BW) of 17beta-estradiol (E2) with both elements, ER+/+, had decreased early hematopoietic progenitors and a shift toward a mature B cell subpopulation, whereas animals with both elements, ER-/-, showed changes only in early hematopoietic progenitors. Hematopoietic element ER+/+ animals exhibited greater E2-induced hematopoietic progenitor and B lymphocyte alterations than those having only nonhematopoietic ERalpha. These data indicate that 1) ERalpha is not necessary for regulating male mouse normal hematopoietic progenitor cell proportions, but is involved in B cell regulation; and 2) ERalpha in hematopoietic elements is predominantly responsible for mediating E2-induced hematopoietic and B cell changes.

This laboratory has studied a number of flavone derivatives for aryl hydrocarbon receptor (AhR) agonist and antagonist potential using cell-free and cell culture systems. The current report extends these investigations by testing the potent AhR antagonist 3'-methoxy-4'-nitroflavone (3'M4'NF) for in vivo activity. Wild-type C57Bl/6 male mice were treated with solvent, benzo[a]pyrene (B[a]P; 150 mg/kg), or concurrently with B[a]P and 3'M4'NF (60 mg/kg; delivered as a split dose). Since B[a]P is bioactivated to genotoxic metabolites by AhR-regulated enzymes, we measured B[a]P-induced chromosomal damage in peripheral blood (i.e. micronuclei) to characterize the antagonistic potential of 3'M4'NF in vivo. The influence of AhR signal transduction was investigated further by challenging wild-type and Ahr null allele mice with B[a]P with and without a 3'M4'NF co-treatment. The micronucleus data obtained from these experiments indicated that 3'M4'NF can attenuate the genotoxicity of B[a]P significantly. Since 3'M4'NF also protected Ahr null allele mice from B[a]P-induced genetic damage, it was apparent that AhR-independent mechanisms contribute to the effects observed. However, as opposed to the protective effects observed with the micronucleus endpoint, histological observations and lethality data indicated that some B[a]P effects are enhanced by 3'M4'NF. Potentiated B[a]P toxicity may be explained by inhibition of basal and induced CYP1A1/2 activities. Both in vitro and in vivo data presented herein support this hypothesis.

The Centers for Disease Control and Prevention and the American Dental Association guidelines recommend sterilization of dental handpieces after each use. Steam autoclaving is the most commonly used sterilization method. However, pressurized steam causes corrosion and partial combustion of the handpiece lubricant, leaving a sticky carbon residue on the turbine which must then be replaced after several usages. Replacement of autoclave-damaged dental handpieces represents a major expense for dentists that may be avoided through the use of less destructive sterilization techniques.