Critical evaluation of key evidence on the human health hazards of exposure to bisphenol A

Despite the fact that more than 5000 safety-related studies have been published on bisphenol A (BPA), there seems to be no resolution of the apparently deadlocked controversy as to whether exposure of the general population to BPA causes adverse effects due to its estrogenicity. Therefore, the Advisory Committee of the German Society of Toxicology reviewed the background and cutting-edge topics of this BPA controversy. The current tolerable daily intake value (TDI) of 0.05 mg/kg body weight [bw]/day, derived by the European Food Safety Authority (EFSA), is mainly based on body weight changes in two- and three-generation studies in mice and rats. Recently, these studies and the derivation of the TDI have been criticized. After having carefully considered all arguments, the Committee had to conclude that the criticism was scientifically not justified; moreover, recently published additional data further support the reliability of the two-and three-generation studies demonstrating a lack of estrogen-dependent effects at and below doses on which the current TDI is based. A frequently discussed topic is whether doses below 5 mg/ kg bw/day may cause adverse health effects in laboratory animals. Meanwhile, it has become clear that positive results from some explorative studies have not been confirmed in subsequent studies with higher numbers of animals or a priori defined hypotheses. Particularly relevant are some recent studies with negative outcomes that addressed effects of BPA on the brain, behavior, and the prostate in rodents for extrapolation to the human situation. The Committee came to the conclusion that rodent data can well be used as a basis for human risk evaluation. Currently published conjectures that rats are insensitive to estrogens compared to humans can be refuted. Data from toxicokinetics studies show that the half-life of BPA in adult human subjects is less than 2 hours and BPA is completely recovered in urine as BPA-conjugates. Tissue deconjugation of BPA-glucuronide and -sulfate may occur. Because of the extremely low quantities, it is only of minor relevance for BPA toxicity. Biomonitoring studies have been used to estimate human BPA exposure and show that the daily intake of BPA is far below the TDI for the general population. Further topics addressed in this article include reasons why some studies on BPA are not reproducible; the relevance of oral versus non-oral exposure routes; the degree to which newborns are at higher systemic BPA exposure; increased BPA exposure by infusions in intensive care units; mechanisms of action other than estrogen receptor activation; and the current regulatory status in Europe, as well as in the USA, Canada, Japan, New Zealand, and Australia. Overall, the Committee concluded that the current TDI for BPA is adequately justified and that the available evidence indicates that BPA exposure represents no noteworthy risk to the health of the human population, including newborns and babies

Neural Circuits Underlying Rodent Sociality: A Comparative Approach

All mammals begin life in social groups, but for some species, social relationships persist and develop throughout the course of an individual’s life. Research in multiple rodent species provides evidence of relatively conserved circuitry underlying social behaviors and processes such as social recognition and memory, social reward, and social approach/avoidance. Species exhibiting different complex social behaviors and social systems (such as social monogamy or familiarity preferences) can be characterized in part by when and how they display specific social behaviors. Prairie and meadow voles are closely related species that exhibit similarly selective peer preferences but different mating systems, aiding direct comparison of the mechanisms underlying affiliative behavior. This chapter draws on research in voles as well as other rodents to explore the mechanisms involved in individual social behavior processes, as well as specific complex social patterns. Contrasts between vole species exemplify how the laboratory study of diverse species improves our understanding of the mechanisms underlying social behavior. We identify several additional rodent species whose interesting social structures and available ecological and behavioral field data make them good candidates for study. New techniques and integration across laboratory and field settings will provide exciting opportunities for future mechanistic work in non-model species

The evolution of primate short-term memory

Short-term memory is implicated in a range of cognitive abilities and is critical for understanding primate cognitive evolution. To investigate the effects of phylogeny, ecology and sociality on short-term memory, we tested the largest and most diverse primate sample to date (421 non-human primates across 41 species) in an experimental delayed-response task. Our results confirm previous findings that longer delays decrease memory performance across species and taxa. Our analyses demonstrate a considerable contribution of phylogeny over ecological and social factors on the distribution of short-term memory performance in primates; closely related species had more similar short-term memory abilities. Overall, individuals in the branch of Hominoidea performed better compared to Cercopithecoidea, who in turn performed above Platyrrhini and Strepsirrhini. Interdependencies between phylogeny and socioecology of a given species presented an obstacle to disentangling the effects of each of these factors on the evolution of shortterm memory capacity. However, this study offers an important step forward in understanding the interspecies and individual variation in short-term memory ability by providing the first phylogenetic reconstruction of this trait’s evolutionary history. The dataset constitutes a unique resource for studying the evolution of primate cognition and the role of short-term memory in other cognitive abilities

C-arm-assisted internal fixation of pediatric mandibular fracture

Abstract Introduction Dentition is one of the main concerns while managing pediatric mandibular fractures. The aim of this study was to assess the results of the usage of intraoperative images with C-arm to identify and protect the roots of nonerupted teeth during open reduction and internal fixation (OR/IF) of pediatric mandibular fractures. Patients and Methods This prospective study was conducted on children who had mandibular fractures with unerupted mandibular teeth appearing on panoramic examination. All patients were managed by OR/IF by titanium miniplates using manual maxillomandibular fixation treated under general anesthesia. Titanium miniplate was positioned according to preoperative radiology. Then C-arm images were taken to confirm the screws position away from the nonerupted teeth. Lastly, the screws were inserted at C-arm-confirmed safe position. Then the results were assessed such as reliability, difficulties of the procedures, operative time, dental occlusion, average intrinsic vertical mouth opening, and complication. Results A total of 20 children with parasymphyseal fractures, with mean age of 6.5 (range: 4–9) years, were included. No difficulties were detected during application of the C-arm during surgery regarding position or projection, and the registered views were clearly seen and easily interpreted. Thus, added duration for C-arm use did not significantly elongate the operative time. Postoperative radiology confirmed proper position of all fixed screws away for the teeth root or unerupted teeth. Conclusion Operative C-arm-guided plate screws positioning and fixation can effectively obviate the risk of injury to tooth root or bud during OR/IF of mandibular

Risk factors associated with aspiration after partial laryngectomies

En Abstract Hypothesis Aspiration and dysphagia still remain the most common drawbacks limiting conservation partial laryngeal surgery. Videofluoroscopic swallowing study (VFSS) has became the gold standard examination that guides the surgeon about important risk factors, helping him in technique selection and anatomical structure preservation, in balance with radical removal of laryngeal neoplasms. Objectives The purpose of this study was to determine the major risk factors for postoperative aspiration using VFSS and how to overcome it following different types of partial laryngectomies. Study design The authors conducted a prospective evaluation comparative study. Patients and methods This study was conducted on patients with laryngeal carcinoma who underwent partial laryngectomy between October 2009 and May 2012. VFSS was carried out to evaluate postoperative swallowing and aspiration. Statistical analyses were performed using Pearson’s χ2 and Spearman’s rank correlation test to detect the major risk factors associated with aspiration. Results Thirty-two patients were enrolled in the present study. Six different types of partial laryngeal surgeries were carried out according to the size and extent of the primary tumor. Twenty-five (78.12%) patients suffered from various degrees of aspiration. Age, smoking, site of tumor, resection of valleculae, epiglottis, hyoid bone, ventricular folds, and true vocal folds were significantly associated with aspiration (P<0.05). Conclusion Aspiration is common after partial laryngeal surgeries but is rarely severe or permanent. VFSS should be used before and after any partial laryngectomy to exclude silent aspiration and the risk for aspiration pneumonia. Aspiration can be minimized with careful patient selection and precise surgical technique selection and perfection

Sudden hearing loss and MTHFR 677C>T/1298A>C gene polymorphisms

Purpose: Sudden hearing loss (SHL) can be caused by vascular disorders favoring impaired cochlear perfusion. A number of inherited prothrombotic risk factors have been considered in the pathogenesis of vascular impairment and the possible role of genetic alterations has recently been suggested. We aimed to investigate the relationship between SHL and MTHFR 677 and 1298 gene polymorphisms. Methods: DNA genotyping was performed on peripheral blood leukocytes in 45 SHL patients and 135 controls. Results: Wild-type MTHFR (677CC/1298AA) was significantly more frequent in the controls (P 0.01), and gene polymorphisms (677CT, 677TT, 1298AC, 1298CC, compound 677CT/1298AC) were significantly more frequent in the patients (P 0.005; Ptrend 0.001). Conclusion: These data suggest that MTHFR gene polymorphisms may be considered as risk factors for SHL and participate on vascular impairment related to this disorder. Further studies, based on large series of patients, are needed to definitely assess the role of this prothrombotic factor in the etiopathogenesis of SHL