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At least 595 records · Page 33

American Society for Radiation Oncology (ASTRO) 2012 Workforce Study: The Radiation Oncologists' and Residents' Perspectives

Purpose: The American Society for Radiation Oncology (ASTRO) conducted the 2012 Radiation Oncology Workforce Survey to obtain an up-to-date picture of the workforce, assess its needs and concerns, and identify quality and safety improvement opportunities. The results pertaining to radiation oncologists (ROs) and residents (RORs) are presented here. Methods: The ASTRO Workforce Subcommittee, in collaboration with allied radiation oncology professional societies, conducted a survey study in early 2012. An online survey questionnaire was sent to all segments of the radiation oncology workforce. Respondents who were actively working were included in the analysis. This manuscript describes the data for ROs and RORs. Results: A total of 3618 ROs and 568 RORs were surveyed. The response rate for both groups was 29%, with 1047 RO and 165 ROR responses. Among ROs, the 2 most common racial groups were white (80%) and Asian (15%), and the male-to-female ratio was 2.85 (74% male). The median age of ROs was 51. ROs averaged 253.4 new patient consults in a year and 22.9 on-treatment patients. More than 86% of ROs reported being satisfied or very satisfied overall with their career. Close to half of ROs reported having burnout feelings. There was a trend toward more frequent burnout feelings with increasing numbers of new patient consults. ROs' top concerns were related to documentation, reimbursement, and patients' health insurance coverage. Ninety-five percent of ROs felt confident when implementing new technology. Fifty-one percent of ROs thought that the supply of ROs was balanced with demand, and 33% perceived an oversupply. Conclusions: This study provides a current snapshot of the 2012 radiation oncology physician workforce. There was a predominance of whites and men. Job satisfaction level was high. However a substantial fraction of ROs reported burnout feelings. Perceptions about supply and demand balance were mixed. ROs top concerns reflect areas of attention for the healthcare sector as a whole.

62 RADIOLOGY AND NUCLEAR MEDICINE↗

Vitamin D Deficiency Is Associated With the Severity of Radiation-Induced Proctitis in Cancer Patients

Purpose: Radiation-induced injury to normal tissues is a common complication of radiation therapy in cancer patients. Considering the role of vitamin D in mucosal barrier hemostasis and inflammatory responses, we investigated whether vitamin D deficiency is associated with the severity of radiation-induced acute proctitis in cancer patients. Methods and Materials: This prospective observational study was conducted in cancer patients referred for pelvic radiation therapy. Serum concentration of 25-hydroxyvitamin D was measured before radiation therapy. Vitamin D deficiency was defined as 25-hydroxyvitamin D concentrations of <35 nmol/L and <40 nmol/L in male and female patients, respectively, based on available normative data. Acute proctitis was assessed after 5 weeks of radiation therapy (total received radiation dose of 50 Gy) and graded from 0 to 4 using Radiation Therapy Oncology Group (RTOG) criteria. Results: Ninety-eight patients (57.1% male) with a mean age of 62.8 ± 9.1 years were studied. Vitamin D deficiency was found in 57 patients (58.1%). Symptoms of acute proctitis occurred in 72 patients (73.4%) after radiation therapy. RTOG grade was significantly higher in patients with vitamin D deficiency than in normal cases (median [interquartile range] of 2 [0.5-3] vs 1 [0-2], P=.037). Vitamin D deficiency was associated with RTOG grade of ≥2, independent of possible confounding factors; odds ratio (95% confidence interval) = 3.07 (1.27-7.50), P=.013. Conclusions: Vitamin D deficiency is associated with increased severity of radiation-induced acute proctitis. Investigating the underlying mechanisms of this association and evaluating the effectiveness of vitamin D therapy in preventing radiation-induced acute proctitis is warranted.

62 RADIOLOGY AND NUCLEAR MEDICINE↗

Pregnancy and Parenthood in Radiation Oncology, Views and Experiences Survey (PROVES): Results of a Blinded Prospective Trainee Parenting and Career Development Assessment

Purpose: Medical training spans nearly a decade, during which many physicians traditionally begin families. Although childrearing responsibilities are shared by men and women in the modern era, differences in time allocated to child care by sex and its potential impact on residency experience merit discussion. Methods and Materials: An anonymous, voluntary, 102-item survey was distributed to 540 current radiation oncology residents and 2014 graduates that asked about marital and parental status, pregnancy during residency, publication productivity, career aspirations, and experiences working with pregnant co-residents. Respondents with children were asked about childcare arrangements, and women who were pregnant during residency were asked about radiation safety, maternity leave, and breastfeeding experiences. Results: A total of 190 respondents completed the survey, 107 men (56.3%) and 84 women (43.7%). Ninety-seven respondents (51.1%) were parents, and 84 (44.2%) reported a pregnancy during residency. Respondents with children more often were male (65% vs 47.3%; P=.014), in a higher level of training (79.3% vs 54.8% were PGY4 or higher; P=.001), were older (median age of 32, interquartile range [IQR]:31-35] vs age 30 [IQR: 29-33]; P<.001), had a PhD (33% vs 19.3%, respectively; P=.033), were married (99% vs 43%, respectively; P<.001), and had a partner who did not work (24.7% vs 1.9%, respectively; <.001). There were no differences in the number of manuscripts published or the number of residents who expressed likelihood of pursing an academic career by parental status. Among parents, men more frequently had partners who did not work (38.1% vs 0%, respectively; P<.001) and reported that their partner performed a greater percentage of childcare duties (70% [IQR: 60%-80%] vs 35% [IQR: 20%-50%], respectively; P<.001). Conclusions: Pregnancy and parenthood are common during residency. Female residents are frequently responsible for more childcare duties than males but have similar research productivity and career aspirations. Further investigation is critical to elucidate gender disparities in parenthood and career development.

62 RADIOLOGY AND NUCLEAR MEDICINE↗

Importance of Local Control in Early-Stage Prostate Cancer: Outcomes of Patients With Positive Post-Radiation Therapy Biopsy Results Treated in RTOG 9408

Purpose: The purpose of this study was to assess the association between positive post-radiation therapy (RT) biopsy results and subsequent clinical outcomes in males with localized prostate cancer. Methods and Materials: Radiation Therapy Oncology Group study 94-08 analyzed 1979 males with prostate cancer, stage T1b-T2b and prostate-specific antigen concentrations of ≤20 ng/dL, to investigate whether 4 months of total androgen suppression (TAS) added to RT improved survival compared to RT alone. Patients randomized to receive TAS received flutamide with luteinizing hormone releasing hormone (LHRH) agonist. According to protocol, patients without evidence of clinical recurrence or initiation of additional endocrine therapy underwent repeat prostate biopsy 2 years after RT completion. Statistical analysis was performed to evaluate the impact of positive post-RT biopsy results on clinical outcomes. Results: A total of 831 patients underwent post-RT biopsy, 398 were treated with RT alone and 433 with RT plus TAS. Patients with positive post-RT biopsy results had higher rates of biochemical failure (hazard ratio [HR] = 1.7; 95% confidence interval [CI] = 1.3-2.1) and distant metastasis (HR = 2.4; 95% CI = 1.3-4.4) and inferior disease-specific survival (HR = 3.8; 95% CI = 1.9-7.5). Positive biopsy results remained predictive of such outcomes after correction for potential confounders such as Gleason score, tumor stage, and TAS administration. Prior TAS therapy did not prevent elevated risk of adverse outcome in the setting of post-RT positive biopsy results. Patients with Gleason score ≥7 with a positive biopsy result additionally had inferior overall survival compared to those with a negative biopsy result (HR = 1.56; 95% CI = 1.04-2.35). Conclusions: Positive post-RT biopsy is associated with increased rates of distant metastases and inferior disease-specific survival in patients treated with definitive RT and was associated with inferior overall survival in patients with high-grade tumors.

62 RADIOLOGY AND NUCLEAR MEDICINE↗

Development and Validation of Consensus Contouring Guidelines for Adjuvant Radiation Therapy for Bladder Cancer After Radical Cystectomy

Purpose: To develop multi-institutional consensus clinical target volumes (CTVs) and organs at risk (OARs) for male and female bladder cancer patients undergoing adjuvant radiation therapy (RT) in clinical trials. Methods and Materials: We convened a multidisciplinary group of bladder cancer specialists from 15 centers and 5 countries. Six radiation oncologists and 7 urologists participated in the development of the initial contours. The group proposed initial language for the CTVs and OARs, and each radiation oncologist contoured them on computed tomography scans of a male and female cystectomy patient with input from ≥1 urologist. On the basis of the initial contouring, the group updated its CTV and OAR descriptions. The cystectomy bed, the area of greatest controversy, was contoured by another 6 radiation oncologists, and the cystectomy bed contouring language was again updated. To determine whether the revised language produced consistent contours, CTVs and OARs were redrawn by 6 additional radiation oncologists. We evaluated their contours for level of agreement using the Landis-Koch interpretation of the κ statistic. Results: The group proposed that patients at elevated risk for local-regional failure with negative margins should be treated to the pelvic nodes alone (internal/external iliac, distal common iliac, obturator, and presacral), whereas patients with positive margins should be treated to the pelvic nodes and cystectomy bed. Proposed OARs included the rectum, bowel space, bone marrow, and urinary diversion. Consensus language describing the CTVs and OARs was developed and externally validated. The revised instructions were found to produce consistent contours. Conclusions: Consensus descriptions of CTVs and OARs were successfully developed and can be used in clinical trials of adjuvant radiation therapy for bladder cancer.

62 RADIOLOGY AND NUCLEAR MEDICINE↗

Tau covariance patterns in Alzheimer's disease patients match intrinsic connectivity networks in the healthy brain

According to the network model of neurodegeneration, the spread of pathogenic proteins occurs selectively along connected brain regions. We tested in vivo whether the distribution of filamentous tau (measured with [ 18 F]flortaucipir-PET), fibrillar amyloid-β ([ 11 C]PIB-PET) and glucose hypometabolism ([ 18 F]FDG-PET) follows the intrinsic functional organization of the healthy brain. We included 63 patients with Alzheimer's disease (AD; 30 male, 63 ± 8 years) who underwent [ 18 F]flortaucipir, [ 11 C]PIB and [ 18 F]FDG PET, and 1000 young adults (427 male, 21 ± 3 years) who underwent task-free fMRI. We selected six predefined disease epicenters as seeds for whole-brain voxelwise covariance analyses to compare correlated patterns of tracer uptake across AD patients against fMRI intrinsic connectivity patterns in young adults. We found a striking convergence between [18F]flortaucipir covariance patterns and intrinsic connectivity maps (range Spearman rho's: 0.32-0.78, p < .001), which corresponded with expected functional networks (range goodness-of-fit: 3.8-8.2). The topography of amyloid-β covariance patterns was more diffuse and less network-specific, while glucose hypometabolic patterns were more spatially restricted than tau but overlapped with functional networks. These findings suggest that the spatial patterns of tau and glucose hypometabolism observed in AD resemble the functional organization of the healthy brain, supporting the notion that tau pathology spreads through circumscribed brain networks and drives neurodegeneration.

60 APPLIED LIFE SCIENCES↗

Relationships between maternally-transferred mercury and hatchling development, behavior, and survival in the American alligator ( Alligator mississippiensis )

Mercury is a toxic and pervasive environmental contaminant that can be transferred from mother to offspring during development. Consequences of maternally-transferred mercury have been observed in vertebrate taxa, including reduced clutch viability, reduced offspring size, and behavioral alterations. These sublethal effects have been assumed to decrease survivorship, though this is seldom assessed. Here, we examined how maternally-transferred mercury interacts with incubation temperature to influence reproductive success, offspring behavior, and subsequent survival in the American alligator (Alligator mississippiensis). We collected nine clutches of eggs from a mercury contaminated reservoir on the Savannah River Site, South Carolina, and incubated eggs at either female- or male-promoting temperatures. Clutch-averaged mercury in egg yolk was high relative to other studies in crocodilians and ranged from 0.248 to 0.554 ppm compared to 0.018–0.052 ppm at a site with low levels of mercury contamination; mercury levels in hatchling blood ranged from 0.090 to 0.490 ppm ($\overline{x}$= 0.240 ppm, n = 158). We found few, mostly negligible correlations between life history traits and mercury but noted a positive relationship with egg mass, possibly mediated by correlated maternal effects such as resource provisioning. Incubation temperature exerted strong effects on hatchling phenotypes, with warmer, male-promoting temperatures producing larger and bolder hatchlings. Presumptive females, produced from cooler incubation temperatures, spent more time in warm areas during behavior trials. Hatchlings were released 10–15 days post-hatch and surveyed over eight months to assess survival. Survivorship was positively correlated with hatchling size and negatively correlated with proportional time spent in warm areas. Presumptive females had much lower survival, and overall survivorship for the eight-month period was 0.185–0.208, depending on the modelling approach. Finally, our study suggests that, within the range of concentrations we observed, incubation temperature has a stronger effect on offspring behavior and survival than maternally-transferred mercury pollution in American alligators.

59 BASIC BIOLOGICAL SCIENCES↗

Pathway modeling of microarray data: A case study of pathway activity changes in the testis following in utero exposure to dibutyl phthalate (DBP)

Pathway activity level analysis, the approach pursued in this study, focuses on all genes that are known to be members of metabolic and signaling pathways as defined by the KEGG database. The pathway activity level analysis entails singular value decomposition (SVD) of the expression data of the genes constituting a given pathway. We explore an extension of the pathway activity methodology for application to time-course microarray data. We show that pathway analysis enhances our ability to detect biologically relevant changes in pathway activity using synthetic data. As a case study, we apply the pathway activity level formulation coupled with significance analysis to microarray data from two different rat testes exposed in utero to Dibutyl Phthalate (DBP). In utero DBP exposure in the rat results in developmental toxicity of a number of male reproductive organs, including the testes. One well-characterized mode of action for DBP and the male reproductive developmental effects is the repression of expression of genes involved in cholesterol transport, steroid biosynthesis and testosterone synthesis that lead to a decreased fetal testicular testosterone. Previous analyses of DBP testes microarray data focused on either individual gene expression changes or changes in the expression of specific genes that are hypothesized, or known, to be important in testicular development and testosterone synthesis. However, a pathway analysis may inform whether there are additional affected pathways that could inform additional modes of action linked to DBP developmental toxicity. We show that Pathway activity analysis may be considered for a more comprehensive analysis of microarray data.

60 APPLIED LIFE SCIENCES↗

Central estrogenic pathways protect against the depressant action of acute nicotine on reflex tachycardia in female rats

We have previously shown that acute exposure of male rats to nicotine preferentially attenuates baroreceptor-mediated control of reflex tachycardia in contrast to no effect on reflex bradycardia. Here, we investigated whether female rats are as sensitive as their male counterparts to the baroreflex depressant effect of nicotine and whether this interaction is modulated by estrogen. Baroreflex curves relating reflex chronotropic responses evoked by i.v. doses (1–16 μg/kg) of phenylephrine (PE) or sodium nitroprusside (SNP), were constructed in conscious freely moving proestrus, ovariectomized (OVX), and estrogen (50 μg/kg/day s.c., 5 days)-replaced OVX (OVXE{sub 2}) rats. Slopes of the curves were taken as a measure of baroreflex sensitivity (BRS{sub PE} and BRS{sub SNP}). Nicotine (100 μg/kg i.v.) reduced BRS{sub SNP} in OVX rats but not in proestrus or OVXE{sub 2} rats. The attenuation of reflex tachycardia by nicotine was also evident in diestrus rats, which exhibited plasma estrogen levels similar to those of OVX rats. BRS{sub PE} was not affected by nicotine in all rat preparations. Experiments were then extended to determine whether central estrogenic receptors modulate the nicotine–BRS{sub SNP} interaction. Intracisteral (i.c.) treatment of OVX rats with estrogen sulfate (0.2 μg/rat) abolished the BRS{sub SNP} attenuating effect of i.v. nicotine. This protective effect of estrogen disappeared when OVX rats were pretreated with i.c. ICI 182,780 (50 μg/rat, selective estrogen receptor antagonist). Together, these findings suggest that central neural pools of estrogen receptors underlie the protection offered by E{sub 2} against nicotine-induced baroreceptor dysfunction in female rats. -- Highlights: ► Estrogen protects against the depressant effect of nicotine on reflex tachycardia. ► The baroreflex response and estrogen status affect the nicotine–BRS interaction. ► The protection offered by estrogen is mediated via central estrogen receptors.

60 APPLIED LIFE SCIENCES↗

Maternal low-dose estradiol-17β exposure during pregnancy impairs postnatal progeny weight development and body composition

Endocrine disrupting chemicals with estrogenic activity play an important role as obesogens. However, studies investigating the most potent natural estrogen, estradiol-17β (E2), at low dose are lacking. We examined endocrine and physiological parameters in gilts receiving distinct concentrations of E2 during pregnancy. We then investigated whether adverse effects prevail in progeny due to a potential endocrine disruption. E2 was orally applied to gilts during the entire period of pregnancy. The concentrations represented a daily consumption at the recommended ADI level (0.05 μg/kg body weight/day), at the NOEL (10 μg/kg body weight/day) and at a high dosage (1000 μg/kg body weight/day). Plasma hormone concentrations were determined using enzyme immuno assays. Offspring body fat was assessed by dual-energy X-ray absorptiometry scanning. In treated gilts receiving 1000 μg E2/kg body weight/day we found significantly elevated plasma E2 levels during pregnancy, paralleled by an increased weight gain. While offspring showed similar weight at birth, piglets exhibited a significant reduction in weight at weaning even though their mothers had only received 0.05 μg E2/kg body weight/day. At 8 weeks of age, specifically males showed a significant increase in overall body fat percentage. In conclusion, prenatal exposure to low doses of E2 affected pig offspring development in terms of body weight and composition. In line with findings from other obesogens, our data suggest a programming effect during pregnancy for E2 causative for the depicted phenotypes. Therefore, E2 exposure may imply a possible contribution to childhood obesity. -- Highlights: ► We investigate the potential role of estradiol-17β (E2) as an obesogen. ► We orally apply E2 at the ADI, NOEL and a high dose to gilts during pregnancy. ► Offspring weight is similar at birth but reduced at weaning even after ADI treatment. ► Male offspring only exhibit an increase in overall body fat percentage prepubertally. ► E2 appears as an endocrine disruptor that might contribute to childhood obesity.

60 APPLIED LIFE SCIENCES↗

In vivo corrosion, tumor outcome, and microarray gene expression for two types of muscle-implanted tungsten alloys

Tungsten alloys are composed of tungsten microparticles embedded in a solid matrix of transition metals such as nickel, cobalt, or iron. To understand the toxicology of these alloys, male F344 rats were intramuscularly implanted with pellets of tungsten/nickel/cobalt, tungsten/nickel/iron, or pure tungsten, with tantalum pellets as a negative control. Between 6 and 12 months, aggressive rhabdomyosarcomas formed around tungsten/nickel/cobalt pellets, while those of tungsten/nickel/iron or pure tungsten did not cause cancers. Electron microscopy showed a progressive corrosion of the matrix phase of tungsten/nickel/cobalt pellets over 6 months, accompanied by high urinary concentrations of nickel and cobalt. In contrast, non-carcinogenic tungsten/nickel/iron pellets were minimally corroded and urinary metals were low; these pellets having developed a surface oxide layer in vivo that may have restricted the mobilization of carcinogenic nickel. Microarray analysis of tumors revealed large changes in gene expression compared with normal muscle, with biological processes involving the cell cycle significantly up‐regulated and those involved with muscle development and differentiation significantly down‐regulated. Top KEGG pathways disrupted were adherens junction, p53 signaling, and the cell cycle. Chromosomal enrichment analysis of genes showed a highly significant impact at cytoband 7q22 (chromosome 7) which included mouse double minute (MDM2) and cyclin‐dependant kinase (CDK4) as well as other genes associated with human sarcomas. In conclusion, the tumorigenic potential of implanted tungsten alloys is related to mobilization of carcinogenic metals nickel and cobalt from corroding pellets, while gene expression changes in the consequent tumors are similar to radiation induced animal sarcomas as well as sporadic human sarcomas. -- Highlights: ► Tungsten/nickel/cobalt, tungsten/nickel/iron, and pure tungsten were studied. ► Male Fischer rats implanted with pellets in gastrocnemius muscle of each hind leg. ► Aggressive rhabdomyosarcomas developed from tungsten/nickel/cobalt pellets only. ► Microarray gene expression analysis was carried out on selected tumors. ► Pellet degradation, urinary metal concentration, and sarcoma were correlated.

60 APPLIED LIFE SCIENCES↗

Oxidative DNA damage of peripheral blood polymorphonuclear leukocytes, selectively induced by chronic arsenic exposure, is associated with extent of arsenic-related skin lesions

There is increasing evidence that oxidative stress is an important risk factor for arsenic-related diseases. Peripheral blood leukocytes constitute an important defense against microorganisms or pathogens, while the research on the impact of chronic arsenic exposure on peripheral blood leukocytes is much more limited, especially at low level arsenic exposure. The purpose of the present study was to explore whether chronic arsenic exposure affects oxidative stress of peripheral blood leukocytes and possible linkages between oxidative stress and arsenic-induced skin lesions. 75 male inhabitants recruited from an As-endemic region of China were investigated in the present study. The classification of arsenicosis was based on the degree of skin lesions. Arsenic levels were measured in drinking water and urine by Atomic Fluorescence Spectroscopy. Urinary 8-hydroxy-2′-deoxyguanosine (8-OHdG) was tested by Enzyme-Linked Immunosorbent Assay. 8-OHdG of peripheral blood leukocytes was evaluated using immunocytochemical staining. 8-OHdG-positive reactions were only present in polymorphonuclear leukocytes (PMNs), but not in monocytes (MNs). The 8-OHdG staining of PMN cytoplasm was observed in all investigated populations, while the 8-OHdG staining of PMN nuclei was frequently found along with the elevated amounts of cell debris in individuals with skin lesion. Urinary arsenic levels were increased in the severe skin lesion group compared with the normal group. No relationship was observed between drinking water arsenic or urine 8-OHdG and the degree of skin lesions. These findings indicated that the target and persistent oxidative stress in peripheral blood PMNs may be employed as a sensitive biomarker directly to assess adverse health effects caused by chronic exposure to lower levels of arsenic. -- Highlights: ► Male inhabitants were investigated from an As-endemic region of China. ► 8-OHdG-positive reactions were only present in polymorphonuclear leukocytes (PMNs). ► 8-OHdG staining of PMN nuclei was paralleled by increased debris of cells. ► Oxidative DNA damage of PMNs is associated with arsenic-related skin lesions.

60 APPLIED LIFE SCIENCES↗

Mass spectrometry-based proteomic analysis of human liver cytochrome(s) P450

The major objective of personalized medicine is to select optimized drug therapies and to a large degree such mission is determined by the expression profiles of cytochrome(s) P450 (CYP). Accordingly, a proteomic case study in personalized medicine is provided by the superfamily of cytochromes P450. Our knowledge about CYP isozyme expression on a protein level is very limited and based exclusively on DNA/mRNA derived data. Such information is not sufficient because transcription and translation events do not lead to correlated levels of expressed proteins. Here we report expression profiles of CYPs in human liver obtained by mass spectrometry (MS)-based proteomic approach. We analyzed 32 samples of human liver microsomes (HLM) of different sexes, ages and ethnicity along with samples of recombinant human CYPs. We have experimentally confirmed that each CYP isozyme can be effectively differentiated by their unique isozyme-specific tryptic peptide(s). Trypsin digestion patterns for almost 30 human CYP isozymes were established. Those findings should assist in selecting tryptic peptides suitable for MS-based quantitation. The data obtained demonstrate remarkable differences in CYP expression profiles. CYP2E1, CYP2C8 and CYP4A11 were the only isozymes found in all HLM samples. Female and pediatric HLM samples revealed much more diverse spectrum of expressed CYPs isozymes compared to male HLM. We have confirmed expression of a number of “rare” CYP (CYP2J2, CYP4B1, CYP4V2, CYP4F3, CYP4F11, CYP8B1, CYP19A1, CYP24A1 and CYP27A1) and obtained first direct experimental data showing expression of such CYPs as CYP2F1, CYP2S1, CYP2W1, CYP4A22, CYP4X1, and CYP26A1 on a protein level. - Highlights: ► First detailed proteomic analysis of CYP isozymes expression in human liver ► Trypsin digestion patterns for almost 30 human CYP isozymes established ► The data obtained demonstrate remarkable differences in CYP expression profiles. ► Female HLM samples revealed more diverse spectrum of CYP isozymes than male. ► First data showing expression of 2F1, 2S1, 2W1, 4A22, 4X1, 26A1 on a protein level.

60 APPLIED LIFE SCIENCES↗

Fluoride-elicited developmental testicular toxicity in rats: Roles of endoplasmic reticulum stress and inflammatory response

Long-term excessive fluoride intake is known to be toxic and can damage a variety of organs and tissues in the human body. However, the molecular mechanisms underlying fluoride-induced male reproductive toxicity are not well understood. In this study, we used a rat model to simulate the situations of human exposure and aimed to evaluate the roles of endoplasmic reticulum (ER) stress and inflammatory response in fluoride-induced testicular injury. Sprague–Dawley rats were administered with sodium fluoride (NaF) at 25, 50 and 100 mg/L via drinking water from pre-pregnancy to gestation, birth and finally to post-puberty. And then the testes of male offspring were studied at 8 weeks of age. Our results demonstrated that fluoride treatment increased MDA accumulation, decreased SOD activity, and enhanced germ cell apoptosis. In addition, fluoride elevated mRNA and protein levels of glucose-regulated protein 78 (GRP78), inositol requiring ER-to-nucleus signal kinase 1 (IRE1), and C/EBP homologous protein (CHOP), indicating activation of ER stress signaling. Furthermore, fluoride also induced testicular inflammation, as manifested by gene up-regulation of tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2), in a nuclear factor-κB (NF-κB)-dependent manner. These were associated with marked histopathological lesions including injury of spermatogonia, decrease of spermatocytes and absence of elongated spermatids, as well as severe ultrastructural abnormalities in testes. Taken together, our results provide compelling evidence that ER stress and inflammation would be novel and significant mechanisms responsible for fluoride-induced disturbance of spermatogenesis and germ cell loss in addition to oxidative stress. - Highlights: • We used a rat model to simulate the situations of human fluoride (F) exposure. • Developmental F exposure induces testicular damage related with oxidative stress. • Endoplasmic reticulum stress is involved in testis disorder and germ cell apoptosis. • Inflammatory response is implicated in impaired spermatogenesis and germ cell loss.

60 APPLIED LIFE SCIENCES↗

Methamidophos alters sperm function and DNA at different stages of spermatogenesis in mice

Methamidophos (MET) is a highly toxic organophosphate (OP) pesticide that is widely used in developing countries. MET has male reproductive effects, including decreased fertility. We evaluated MET effects on sperm quality, fertilization and DNA integrity, exploring the sensitivity of different stages of spermatogenesis. Adult male mice received MET (3.75 or 5 mg/kg-bw/ip/day/4 days) and were euthanized 1, 28 or 45 days post-treatment (dpt) to evaluate MET's effects on epididymal maturation, meiosis or mitosis, respectively. Spermatozoa were obtained from the cauda epididymis–vas deferens and were evaluated for sperm quality, acrosome reaction (AR; Coomassie staining), mitochondrial membrane potential (by JC-1), DNA damage (comet assay), oxidative damage (malondialdehyde (MDA) production), in vitro fertilization and protein phosphorylation (immunodetection), and erythrocyte acetylcholinesterase (AChE) activity. At 1-dpt, MET inhibited AChE (43–57%) and increased abnormal cells (6%). While at 28- and 45-dpt, sperm motility and viability were significantly reduced with an increasing MET dose, and abnormal morphology increased at 5 mg/kg/day/4 days. MDA and mitochondrial activity were not affected at any dose or time. DNA damage (OTM and %DNA) was observed at 5 mg/kg/day/4 days in a time-dependent manner, whereas both parameters were altered in cells from mice exposed to 3.75 mg/kg/day/4 days only at 28-dpt. Depending on the time of collection, initial-, spontaneous- and induced-AR were altered at 5 mg/kg/day/4 days, and the fertilization capacity also decreased. Sperm phosphorylation (at serine and tyrosine residues) was observed at all time points. Data suggest that meiosis and mitosis are the more sensitive stages of spermatogenesis for MET reproductive toxicity compared to epididymal maturation. - Highlights: • Methamidophos alters sperm cell function at different stages of spermatogenesis. • Testicular stages of spermatogenesis are more sensitive to methamidophos toxicity. • Methamidophos causes sperm DNA damage at mitosis, meiosis and epididymal maturation. • Sperm cell damage by methamidophos exposure may be related to protein phosphorylation.

60 APPLIED LIFE SCIENCES↗

Chronic nandrolone administration promotes oxidative stress, induction of pro-inflammatory cytokine and TNF-α mediated apoptosis in the kidneys of CD1 treated mice

Nandrolone decanoate administration and strenuous exercise increase the extent of renal damage in response to renal toxic injury. We studied the role played by oxidative stress in the apoptotic response caused by nandrolone decanoate in the kidneys of strength-trained male CD1 mice. To measure cytosolic enzyme activity, glutathione peroxidase (GPx), glutathione reductase (GR) and malondialdehyde (MDA) were determined after nandrolone treatment. An immunohistochemical study and Western blot analysis were performed to evaluate cell apoptosis and to measure the effects of renal expression of inflammatory mediators (IL-1β, TNF-α) on the induction of apoptosis (HSP90, TUNEL). Dose-related oxidative damage in the kidneys of treated mice is shown by an increase in MDA levels and by a reduction of antioxidant enzyme GR and GPx activities, resulting in the kidney's reduced radical scavenging ability. Renal specimens of the treated group showed relevant glomeruli alterations and increased immunostaining and protein expressions, which manifested significant focal segmental glomerulosclerosis. The induction of proinflammatory cytokine expression levels was confirmed by Western blot analysis. Long-term administration of nandrolone promotes oxidative injury in the mouse kidneys. TNF-α mediated injury due to nandrolone in renal cells appears to play a role in the activation of both the intrinsic and extrinsic apoptosis pathways. - Highlights: • We analyze abuse of nandrolone decanoate in strength-trained male CD1 mice. • Nandrolone decanoate administration increases oxidative stress. • Increased cytokine expressions were observed. • Renal apoptosis was described. • Long-term administration of nandrolone promotes oxidative injury in mice kidney.

60 APPLIED LIFE SCIENCES↗

Elevated levels of plasma uric acid and its relation to hypertension in arsenic-endemic human individuals in Bangladesh

Blood uric acid has been recognized as a putative marker for cardiovascular diseases (CVDs). CVDs are the major causes of arsenic-related morbidity and mortality. However, the association of arsenic exposure with plasma uric acid (PUA) levels in relation to CVDs has not yet been explored. This study for the first time demonstrated the associations of arsenic exposure with PUA levels and its relationship with hypertension. A total of 483 subjects, 322 from arsenic-endemic and 161 from non-endemic areas in Bangladesh were recruited as study subjects. Arsenic concentrations in the drinking water, hair and nails of the study subjects were measured by inductively coupled plasma mass spectroscopy. PUA levels were measured using a colorimetric method. We found that PUA levels were significantly (p < 0.001) higher in males and females living in arsenic-endemic areas than those in non-endemic area. Arsenic exposure (water, hair and nail arsenic) levels showed significant positive correlations with PUA levels. In multiple regression analyses, arsenic exposure levels were found to be the most significant contributors on PUA levels among the other variables that included age, body mass index, blood urea nitrogen, and smoking. There were dose–response relationships between arsenic exposure and PUA levels. Furthermore, diastolic and systolic blood pressure showed significant positive correlations with PUA levels. Finally, the average PUA levels were significantly higher in the hypertensive group than those in the normotensive group in both males and females living in arsenic-endemic areas. These results suggest that arsenic exposure-related elevation of PUA levels may be implicated in arsenic-induced CVDs. - Highlights: • PUA levels were higher in arsenic-endemic subjects than in non-endemic subjects. • Drinking water, hair and nail arsenic showed significant associations with PUA levels. • Drinking water, hair and nail arsenic showed dose–response relationships with PUA. • Arsenic-endemic hypertensive study subjects had elevated levels of PUA. • Increased PUA levels may be implicated in arsenic-induced CVDs.

60 APPLIED LIFE SCIENCES↗

24-hour human urine and serum profiles of bisphenol A: Evidence against sublingual absorption following ingestion in soup

Extensive first-pass metabolism of ingested bisphenol A (BPA) in the gastro-intestinal tract and liver restricts blood concentrations of bioactive BPA to < 1% of total BPA in humans and non-human primates. Absorption of ingested BPA through non-metabolizing tissues of the oral cavity, recently demonstrated in dogs, could lead to the higher serum BPA concentrations reported in some human biomonitoring studies. We hypothesized that the extensive interaction with the oral mucosa by a liquid matrix, like soup, relative to solid food or capsules, might enhance absorption through non-metabolizing oral cavity tissues in humans, producing higher bioavailability and higher serum BPA concentrations. Concurrent serum and urine concentrations of d6-BPA, and its glucuronide and sulfate conjugates, were measured over a 24 hour period in 10 adult male volunteers following ingestion of 30 μg d6-BPA/kg body weight in soup. Absorption of d6-BPA was rapid (t{sub 1/2} = 0.45 h) and elimination of the administered dose was complete 24 h post-ingestion, evidence against any tissue depot for BPA. The maximum serum d6-BPA concentration was 0.43 nM at 1.6 h after administration and represented < 0.3% of total d6-BPA. Pharmacokinetic parameters, pharmacokinetic model simulations, and the significantly faster appearance half-life of d6-BPA-glucuronide compared to d6-BPA (0.29 h vs 0.45 h) were evidence against meaningful absorption of BPA in humans through any non-metabolizing tissue (< 1%). This study confirms that typical exposure to BPA in food produces picomolar to subpicomolar serum BPA concentrations in humans, not nM concentrations reported in some biomonitoring studies.

60 APPLIED LIFE SCIENCES↗