3-Ethenylpyridine Measured in Urine of Active and Passive Smokers: A Promising Biomarker and Toxicological Implications.

In studies of tobacco toxicology, including comparisons of different tobacco products and exposure to secondhand or thirdhand smoke, exposure assessment using biomarkers is often useful. Some studies have indicated that most of the toxicity of tobacco smoke is due to gas-phase compounds. 3-Ethenylpyridine (3-EP) is a major nicotine pyrolysis product occurring in the gas phase of tobacco smoke. It has been used extensively as an environmental tracer for tobacco smoke. 3-EP would be expected to be a useful tobacco smoke biomarker as well, but nothing has been published about its metabolism and excretion in humans. In this Article we describe a solid-phase microextraction (SPME) GC-MS/MS method for determination of 3-EP in human urine and its application to the determination of 3-EP in the urine of smokers and people exposed to secondhand smoke. We conclude that 3-EP is a promising biomarker that could be useful in studies of tobacco smoke exposure and toxicology. We also point out the paucity of data on 3-EP toxicity and suggest that additional studies are needed.

Tunable, Injectable Hydrogels Based on Peptide-Cross-Linked, Cyclized Polymer Nanoparticles for Neural Progenitor Cell Delivery.

A PEG-based cyclized vinyl polymer was synthesized via one-step RAFT polymerization and used as a precursor of injectable hydrogels. Dithiol linkers including laminin-derived peptides containing IKVAV and YIGSR sequences and DTT were used for gelation. Fast and adjustable gelation rate was achieved through nucleophile-initiated thiol-Michael reaction under physiological conditions. Low swelling ratio and moderate degradation rate of the formed hydrogels were observed. 3D encapsulation of neural progenitor cells in the synthetic hydrogel showed good cell viability over 8 days. The long-term cell survival and proliferation were promoted by the introduction of laminin-derived peptides. This hydrogel platform based on peptide-cross-linked, cyclized vinyl polymers can be used as a universal hydrogel template for 3D cell encapsulation.

Adverse outcome pathways: opportunities, limitations and open questions.

Adverse outcome pathways (AOPs) are a recent toxicological construct that connects, in a formalized, transparent and quality-controlled way, mechanistic information to apical endpoints for regulatory purposes. AOP links a molecular initiating event (MIE) to the adverse outcome (AO) via key events (KE), in a way specified by key event relationships (KER). Although this approach to formalize mechanistic toxicological information only started in 2010, over 200 AOPs have already been established. At this stage, new requirements arise, such as the need for harmonization and re-assessment, for continuous updating, as well as for alerting about pitfalls, misuses and limits of applicability. In this review, the history of the AOP concept and its most prominent strengths are discussed, including the advantages of a formalized approach, the systematic collection of weight of evidence, the linkage of mechanisms to apical end points, the examination of the plausibility of epidemiological data, the identification of critical knowledge gaps and the design of mechanistic test methods. To prepare the ground for a broadened and appropriate use of AOPs, some widespread misconceptions are explained. Moreover, potential weaknesses and shortcomings of the current AOP rule set are addressed (1) to facilitate the discussion on its further evolution and (2) to better define appropriate vs. less suitable application areas. Exemplary toxicological studies are presented to discuss the linearity assumptions of AOP, the management of event modifiers and compensatory mechanisms, and whether a separation of toxicodynamics from toxicokinetics including metabolism is possible in the framework of pathway plasticity. Suggestions on how to compromise between different needs of AOP stakeholders have been added. A clear definition of open questions and limitations is provided to encourage further progress in the field.

Preventive effect of American ginseng against premature ovarian failure in a rat model.

Preclinical Research Premature ovarian failure (POF) is defined by the WHO as the loss of physiological ovarian function before the age of 40. The effect of American ginseng and its underlying mechanisms in preventing and treating premature ovarian failure (POF) was studied in female Sprague-Dawley rats where POF was induced by ip administration of 4-vinylcyclohexene diepoxide (VCD). Rat behavior, serum hormone levels, ovarian and uterine size, pathological features, and ovarian tissue expression of genes associated with POF were assessed in controls, untreated POF model rats, and POF model rats treated with low- (1.125 g/kg), medium- (2.25 g/kg), and high-dose (4.5 g/kg) American ginseng. Compared with untreated POF model rats, those treated with medium- and high-dose American ginseng had more stable behavior and better coat appearance as well as serum hormone levels closer to those in control rats. Moreover, treatment with medium- or high-dose American ginseng increased ovarian and uterine size. Hematoxylin and eosin-staining revealed mature follicles and endometrium with an alternating concave/convex surface structure with visible capillaries and glands in ginseng- treated POF rats. PLA2G4A expression was positively correlated with POF, while the expression levels of PAPPA, STC2, CCL2, and NELL1 were negatively correlated with POF. Our study showed that American ginseng may effectively prevent POF and alleviate POF symptoms by regulating serum hormone levels and altering the expression levels of genes related to POF in ovarian tissue.

[Index contaminants and target organs]. / Inquinanti indice e organi bersaglio.

SENTIERI Project evaluates the health impact of environmental exposures on residential population of National Priority Contaminated Sites (NPCSs). It takes into account a priori etiological hypotheses, based on the epidemiological evidence of an association between those exposures and selected diseases or causes of death. Building on the previous chapter, this one acts as a blueprint for future causal inferences based on scientific evidence relating to the health effects of exposure to specific pollutants present in the sites. In order to select the relevant pollutants, we make use of data concerning soil, aquifers, the food chain and the atmosphere. For each pollutant, we indicate cancer site and target organs, for non-neoplastic diseases, based on scientific assessment by international Agencies. We have chosen to focus on two sites: Brescia-Caffaro and Priolo. This method may conceivably be used by SENTIERI in the future to carry out more specific studies and provides the basis for a systematic analysis of contaminated sites.

Low-Intensity Pulsed Ultrasound Promotes Repair of 4-Vinylcyclohexene Diepoxide-Induced Premature Ovarian Insufficiency in SD Rats.

Women with premature ovarian insufficiency (POI) may be more vulnerable to a variety of health risks. To seek a new method to treat the disease, the effects of low-intensity pulsed ultrasound (LIPUS) on promoting repair of ovarian injury in female SD rats induced by 4-vinylcyclohexene diepoxide (VCD) were explored in this research. A total of 24 female SD rats were subjected to intraperitoneal injection of VCD to induce POI. Successful modeling was achieved in 22 rats, which were then randomized into VCD + LIPUS group (n = 13) and VCD group (n = 9). The control group (n = 5) was injected with equal normal saline. Hematoxylin and eosin staining, enzyme-linked immunosorbent assay, Western blot analysis, scanning electron microscope, immunohistochemistry, and terminal deoxynucleotidyl transferase-mediated nick end labeling assay were applied to detect the results. The results indicated that rats in the VCD group showed disorder in the estrous cycle, the number of atresia follicles and apoptosis granulosa cells increased (p < .05). After the LIPUS treatment, the estrous cycle recovered, the number of follicles increased (p < .05), the level of E2 and anti-Müllerian hormone enhanced (p < .05), and the follicle-stimulating hormone decreased (p < .05). The expression of NF-κB p65, TNFα, Bax, ATF4, and caspase-3 in ovarian tissue was significantly decreased (p < .05). These findings showed that LIPUS could promote the repair of the VCD-induced ovarian damage in SD rats, which has the potential to be further applied in the clinic.

Plasma Membrane Affiliated AMPA GluA1 in Estrogen Receptor ß-containing Paraventricular Hypothalamic Neurons Increases Following Hypertension in a Mouse Model of Post-menopause.

Sex and ovarian function contribute to hypertension susceptibility, however, the mechanisms are not well understood. Prior studies show that estrogens and neurogenic factors, including hypothalamic glutamatergic NMDA receptor plasticity, play significant roles in rodent hypertension. Here, we investigated the role of sex and ovarian failure on AMPA receptor plasticity in estrogen-sensitive paraventricular nucleus (PVN) neurons in naïve and angiotensin II (AngII) infused male and female mice and female mice at early and late stages of accelerated ovarian failure (AOF). High-resolution electron microscopy was used to assess the subcellular distribution of AMPA GluA1 in age-matched male and female estrogen receptor beta (ERß) enhanced green fluorescent protein (EGFP) reporter mice as well as female ERß-EGFP mice treated with 4-vinylcyclohexene diepoxide. In the absence of AngII, female mice at a late stage of AOF displayed higher levels of GluA1 on the plasma membrane, indicative of functional protein, in ERß-expressing PVN dendrites when compared to male, naïve female and early stage AOF mice. Following slow-pressor AngII infusion, males, as well as early and late stage AOF females had elevated blood pressure. Significantly, only late stage-AOF female mice infused with AngII had an increase in GluA1 near the plasma membrane in dendrites of ERß-expressing PVN neurons. In contrast, prior studies reported that plasmalemmal NMDA GluN1 increased in ERß-expressing PVN dendrites in males and early, but not late stage AOF females. Together, these findings reveal that early and late stage AOF female mice display unique molecular signatures of long-lasting synaptic strength prior to, and following hypertension.

Tissue reaction after subcutaneous implants of a new material composed of ethylene-vinyl acetate and starch for future use as a biomaterial.

This study aimed to evaluate the tissue reaction of ethylene-vinyl acetate (EVA) in 4 different compositions and processing: EVA foamed at high pressure with ultrasound (EVACU); EVA with 15% starch foamed at high pressure with ultrasound (EVAMCU); EVA with 15% starch foamed at high pressure without ultrasound and EVA foamed at high pressure without ultrasound as future use as a porous scaffold. Scanning electron microscopy images showed the influence of starch, reducing the diameter of pores. The number of open pores was also reduced with the addition of starch. The ultrasound applied during the manufacturing of composites does not affect these characteristics. Eighteen rats were used to test the tissue reaction of materials and PTFE (polytetrafluoroethylene), proven biocompatible material. After 7, 15, and 60 days of surgery, the materials were removed and processed for microscopic evaluation and counting of the inflammatory infiltrate. The data shows inflammatory reaction similar to PTFE. However, in the quantitative analysis at 60 days, the EVACU and EVAMCU showed less quantity of mononuclear cells (p < 0.05). Thus, the results suggest that the use of ultrasound in the production method (EVA) seems to have improved cell behavior regarding the reduction of infiltration over the period, with tissue response equivalent to the PTFE. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 107B: 400-407, 2019.

Glucose homeostasis in rats treated with 4-vinylcyclohexene diepoxide is not worsened by dexamethasone treatment.

4-vinilcyclohexene diepoxide (4-VCD) causes premature ovarian failure and may result in estrogen deficiency, characterizing the transition to estropause in rodents (equivalent to menopause in women). Estropause/menopause is associated with metabolic derangements such as glucose intolerance and insulin resistance. Glucocorticoids (GCs) are known to exert diabetogenic effects. Thus, we aimed to investigate whether rats with premature ovarian failure are more prone to the diabetogenic effects of GC. For this, immature female rats received daily injections of 4-VCD [160mg/kg body weight (b.w.), intraperitoneally (i.p.)] for 15 consecutive days, whereas control rats received vehicle. After 168days of the completion of 4-VCD administration, rats were divided into 4 groups: CTL-received daily injections of saline (1mL/kg, b.w., i.p.) for 5days; DEX-received daily injections of dexamethasone (1mg/kg, b.w., i.p.) for 5days; VCD-treated as CTL group; VCD+DEX-treated as DEX group. Experiments and euthanasia occurred one day after the last dexamethasone injection. 4-VCD-treated rats exhibited ovary hypotrophy and reduced number of preantral follicles (p<0.05). Premature ovarian failure had no impact on the body weight gain or food intake, but both were reduced by the effects of dexamethasone. The increase in blood glucose, plasma insulin and triacylglycerol levels as well as the reduction in insulin sensitivity caused by dexamethasone treatment was not exacerbated in the VCD+DEX group of rats. Premature ovarian failure did change neither the hepatic content of glycogen and triacylglycerol nor the glycerol release from perigonadal adipose tissue. Glucose intolerance was observed in the VCD group after an ipGTT (p<0.05), but not after an oral glucose challenge. Glucose intolerance and compensatory pancreatic ß-cell mass caused by GC were not modified by ovarian failure in the VCD+DEX group. We conclude that reduced ovarian function has no major implications on the diabetogenic effects promoted by GC treatment, indicating that other factors related to aging may make rats more vulnerable to GC side effects on glucose metabolism.

Suppression of spermatogenesis by etonogestrel implants with depot testosterone: potential for long-acting male contraception.

The coadministration of a progestogen with testosterone increases the degree of suppression of spermatogenesis and is one approach to the development of hormonal male contraception. Depot formulations may allow a reduction in dosage, minimizing adverse effects. We have investigated the effects of a sc implant containing the progestogen etonogestrel (Implanon) with depot testosterone on spermatogenesis in normal men. Twenty-eight men were randomized to receive either one or two etonogestrel implants, removed after 24 wk. All men additionally received 400 mg testosterone pellets on d 1 and at 12 wk. Four men withdrew during the study, three because of side effects. Testosterone concentrations remained within the physiological range during treatment, although they were overall slightly reduced, compared with pretreatment. Both groups showed marked suppression of spermatogenesis, nine men in each group achieving azoospermia (64% and 75% in the one- and two-implant groups, respectively). Sperm concentrations in 13/14 men in the two-implant group fell to 0.1 x 10(6)/ml or less. Spermatogenic suppression was more variable in the one-implant group, with partial recovery in three men. Incomplete suppression of spermatogenesis in the one-implant group was associated with less complete suppression of gonadotropins. There were no significant changes in body weight, hemoglobin, hematocrit, or high-density lipoprotein cholesterol concentrations during treatment. These data demonstrate that etonogestrel implants with depot testosterone provide effective suppression of spermatogenesis with reduced metabolic effects and are, therefore, a promising approach to the development of long-acting yet reversible male contraception.

Occupational carcinogenesis: the Louisville experience with vinyl chloride-associated hepatic angiosarcoma.

Hepatic angiosarcoma in man was first associated with exposure to vinyl chloride in Louisville, Kentucky, where it was identified in 10 persons from a single vinyl chloride polymerization plant; clinical manifestations are summarized herein. Following prolonged exposure to vinyl chloride, the onset of this disease is insidious and the clinical picture is that of nonspecific hepatic injury with mildly abnormal biochemical liver test results. Carcinoembryonic antigen and alpha fetoprotein are undetectable. Radionuclide and angiographic studies of liver show characteristic but nondiagnostic abnormalities. A definite diagnosis is usually made only by open liver biopsy. Treatment is unsatisfactory but chemotherapy seems to prolong survival. Average survival from diagnosis is about 12 months. Overt liver failure usually occurs only as a preterminal event and was the major cause of death in all of our patients. Preventive measures are now in effect in the plant. This experience illustrates the importance of the clinician in occupationally-related cancer.

Pharmacokinetics of etonogestrel and ethinylestradiol released from a combined contraceptive vaginal ring.

OBJECTIVE: To assess the pharmacokinetics of etonogestrel and ethinylestradiol released from a novel combined contraceptive vaginal ring (NuvaRing) releasing etonogestrel 120microg and ethinylestradiol 15 microg per day and compare them with those of a combined oral contraceptive containing desogestrel 150 microg/ethinylestradiol 30 microg (DSG/EE COC). DESIGN AND SETTING: This was a nonblind, randomised, crossover study in 16 healthy women. METHODS: All volunteers received one cycle of DSG/EE COC before being randomised to 1 of 2 treatment groups. The participants in group 1 received 1 cycle of DSG/EE COC, a treatment period with NuvaRing and an intravenous bolus injection of etonogestrel/ethinylestradiol (150 microg/30 microg). Those in group 2 received a NuvaRing treatment period, 1 cycle of DSG/EE COC and the same intravenous bolus injection. RESULTS AND CONCLUSIONS: After the insertion of NuvaRing, maximum serum concentrations of etonogestrel and ethinylestradiol were achieved in approximately 1 week. The concentrations subsequently showed a gradual linear decrease in time. The maximum serum concentrations of etonogestrel and ethinylestradiol were approximately 40 and 30%, respectively, of those for the DSG/EE COC. In comparison with the DSG/EE COC, the absolute bioavailability for NuvaRing was higher for etonogestrel (102.9 vs 79.2%) and similar for ethinylestradiol (55.6 vs 53.8%). Taking the difference in daily doses into account, systemic exposure to etonogestrel was similar for NuvaRing and the DSG/EE COC, whereas systemic exposure to ethinylestradiol with NuvaRing was only approximately 50% of that for the DSG/EE COC.

A cohort study on vinyl chloride manufacturers in Italy: study design and preliminary results.

A cohort mortality study of 5000 vinyl chloride manufacturers is ongoing in 9 Italian plants. They represent the entire workforce of those ever employed in the production of the monomer and its polymerization. The objectives of the study are to investigate the mortality of the exposed population and to clear up the carcinogenic spectrum of vinyl chloride. This article gives the results for 3 out of 9 plants, Rosignano, Ferrara and Ravenna, which represent about 25% of the total cohort. The expected deaths have been calculated using the mortality rates of the Italian population. For the deceased persons information from the death certificates were used in the analysis of mortality; additional clinical and pathological data were collected (best pathological evidence, b.p.e.). In Ferrara a statistically significant excess for all malignant tumors and lung cancer was detected. In Rosignano and Ravenna the number of observed deaths were small and therefore no comments can be made on cancer mortality. The cohort study is ongoing in the 6 remaining cohorts and the future analysis will consider duration and level of exposure and latency.

Review of pulmonary effects of poly(vinyl chloride) and vinyl chloride exposure.

The contributions of several recent reports to the definition of pulmonary effects of PVC dust inhalation are reviewed. Granulomatous reaction, with inclusion of PVC particles in macrophages and histocytes, and associated interstitial pulmonary fibrosis have been found to lead to exertional dyspnoea, diffuse micronodular chest radiographic opacities and restrictive pulmonary dysfunction. The effects of vinyl chloride (VC) monomer (gas) on proteins and the immunologic mechanisms triggered by the altered protein are possible mechanisms for the development in some cases of interstitial pulmonary fibrosis secondary to VC exposure. Vinyl chloride, a confirmed carcinogen, has been associated with, among other malignant tumors, a significant increase in the incidence of lung cancer. The magnitude of this effect has not yet been completely evaluated.

Excess lung cancer risk in a synthetic chemicals plant.

A standardized mortality ratio of 1.49 for respiratory system cancer (42 observed deaths versus 28.2 expected, p less than 0.01) was observed among a cohort of 4806 males employed at a synthetic chemicals plant since its startup in 1942. Upon review of pathologic material, the excess was found to be limited to adenocarcinoma and large cell undifferentiated lung cancer. Many of the workers had been exposed to vinyl chloride, as well as to chlorinated solvents, poly(vinyl chloride) (PVC) dust, acrylates and acrylonitrile. To evaluate the association between lung cancer and occupational chemical exposures, detailed work histories for each cohort member were combined with exposure ratings for each of 19 chemicals for each job for each calendar year since 1942. A serially additive expected dose model was then constructed which compared the doses of the chemicals observed for the lung cancer cases to the doses expected based on subcohorts without lung cancer individually matched to the cases. PVC dust appeared to be the most likely etiologic agent (p = 0.037). Time trends of PVC dust exposure indicated a potential latent period of 5-16 years before death.

Epidemiological study of pneumoconiosis in the Italian poly(vinyl chloride) industry.

Among 1216 workers employed in a poly(vinyl chloride) production factory, 20 cases of pneumoconiosis were found. None of these workers had had previous exposure to organic or inorganic dusts; 731 had been exposed to PVC dust (employed in drying, sacking and blending of polymer) and 485 had been exposed to monomer alone. Chest x-ray films were read by two independent physicians utilizing the ILO/UC Pneumoconiosis Classification, 1971. X-ray abnormalities were characterized by limited profusion, irregular type and low gravidity; in a small percentage of cases these were associated with slight restrictive respiratory function impairments. All 20 workers with PVC-induced pneumoconiosis had been exposed to high PVC dust pollution for at least five years. Mild nonspecific alterations (profusion of 0/1 class) were found both in the group exposed to PVC dust and in the group exposed to VCM alone. Such changes (observed in 388 cases, 31.9% of the whole population), are related mainly to age and smoking habits, and the role of exposure is minor.

Review of epidemiologic study results of vinyl chloride-related compounds.

Epidemiologic study results addressing the carcinogenicity of six compounds related to vinyl chloride (vinylidene chloride, trichloroethylene, perchloroethylene, carbon tetrachloride, ethylene dibromide and epichlorohydrin) are reviewed. The study results suggest an increased carcinogenic risk among workers exposed to epichlorohydrin and to dry cleaning and degreasing solvents. Although several studies report no significant excess of cancer mortality, an evaluation of the design of these investigations demonstrates that these negative cohort studies consisted of populations of insufficient sample size and latency to permit any meaningful conclusions regarding carcinogenic risk. Therefore, experimental studies must be relied upon to determine whether several of these substances pose a potential carcinogenic risk to humans. Available evidence indicates that all of these substances have demonstrated a carcinogenic response in experimental animals and most are mutagenic in experimental test systems.

Power considerations in studies of reproductive effects of vinyl chloride and some structural analogs.

We review the evidence examining the relation of reproductive function and exposure to vinyl chloride and selected structural analogs. Investigation of these compounds for possible reproductive effects has focused on paternal exposure, a much less well studied route than maternal exposure. Drawing on animal models, we discuss what is known about the possible reproductive consequences of exposure to the father as well as to the mother. In evaluating the studies of reproductive outcome in relation to vinyl chloride or analogs, we consider what biologic model may have been tested and whether there was statistical power to detect moderate increases in risk. Parameters influencing statistical power are reviewed, and recommended sample sizes are set out which would insure sufficient power, in future studies, to detect adverse effects.