Identifying an indoor air exposure limit for formaldehyde considering both irritation and cancer hazards

Formaldehyde is a well-studied chemical and effects from inhalation exposures have been extensively characterized in numerous controlled studies with human volunteers, including asthmatics and other sensitive individuals, which provide a rich database on exposure concentrations that can reliably produce the symptoms of sensory irritation. Although individuals can differ in their sensitivity to odor and eye irritation, the majority of authoritative reviews of the formaldehyde literature have concluded that an air concentration of 0.3 ppm will provide protection from eye irritation for virtually everyone. A weight of evidence-based formaldehyde exposure limit of 0.1 ppm (100 ppb) is recommended as an indoor air level for all individuals for odor detection and sensory irritation. It has recently been suggested by the International Agency for Research on Cancer (IARC), the National Toxicology Program (NTP), and the US Environmental Protection Agency (US EPA) that formaldehyde is causally associated with nasopharyngeal cancer (NPC) and leukemia. This has led US EPA to conclude that irritation is not the most sensitive toxic endpoint and that carcinogenicity should dictate how to establish exposure limits for formaldehyde. In this review, a number of lines of reasoning and substantial scientific evidence are described and discussed, which leads to a conclusion that neither point of contact nor systemic effects of any type, including NPC or leukemia, are causally associated with exposure to formaldehyde. This conclusion supports the view that the equivocal epidemiology studies that suggest otherwise are almost certainly flawed by identified or yet to be unidentified confounding variables. Thus, this assessment concludes that a formaldehyde indoor air limit of 0.1 ppm should protect even particularly susceptible individuals from both irritation effects and any potential cancer hazard

The bituminous mixtures of Kavuşan Höyük (SE Turkey) from the end of the 3rd millennium (2000BC) to the Medieval period (AD 14th century): Composition and origin

Bituminous mixtures were observed on potsherds at Kavuşan Höyük, one of the rescue excavations along the Upper Tigris River in southeastern Turkey. Analysis of 26 samples from six periods spanning from the end of the 3rd millennium BC to the Medieval period (AD 14th century), has shown that bituminous mixtures possess the classical gross composition of most bitumen-bearing mixtures analysed in many archaeological sites of the Near East and the Gulf of Arabia. To search for the geological sources of bitumen, oil seeps, oil stained rocks and crude oils from Turkey and Northern Iraq were analysed as reference using the same geochemical tools: biomarkers and stable isotope composition. The principal conclusion is that the bitumen has been imported from the Eruh outcrop, 120. km east of Kavuşan Höyük. Additionally, the bitumen from Eruh was imported to Kavuşan over a long time period, from the end of the 3rd millennium BC to the AD 14th century. © 2012 Elsevier Ltd

The bituminous mixtures of Kavusan Hoyuk (SE Turkey) from the end of the 3rd millennium (2000 BC) to the Medieval period (AD 14th century): Composition and origin

WOS: 000314458000002Bituminous mixtures were observed on potsherds at Kavusan Hoyuk, one of the rescue excavations along the Upper Tigris River in southeastern Turkey. Analysis of 26 samples from six periods spanning from the end of the 3rd millennium BC to the Medieval period (AD 14th century), has shown that bituminous mixtures possess the classical gross composition of most bitumen-bearing mixtures analysed in many archaeological sites of the Near East and the Gulf of Arabia. To search for the geological sources of bitumen, oil seeps, oil stained rocks and crude oils from Turkey and Northern Iraq were analysed as reference using the same geochemical tools: biomarkers and stable isotope composition. The principal conclusion is that the bitumen has been imported from the Eruh outcrop, 120 km east of Kavusan Hoyuk. Additionally, the bitumen from Eruh was imported to Kavusan over a long time period, from the end of the 3rd millennium BC to the AD 14th century. (C) 2012 Elsevier Ltd. All rights reserved

Identification and origin of bitumen in Neolithic artefacts from Demirkoy Hoyuk (8100 BC): Comparison with oil seeps and crude oils from southeastern Turkey

Two ring-like artefacts from the aceramic Neolithic site of Demirkoy Hoyuk in southeastern Turkey were analysed using geochemical techniques in order to determine whether they were prepared using a bitumen amalgam or not. The artefacts, dated 8 100 BC, are early evidence of the innovative use of a petroleum-based material to prepare pieces of ornaments (beads, rings, etc.) for the elite of a Neolithic settlement. In order to trace the source of the presumed bitumen, two oil seeps, Bogazkoy and Yesilli, were sampled. To complete the genetic references, geochemical data on crude oils from the main oil fields from the area were compiled

Does Surgical Margin Impact Recurrence in Noninvasive Intraductal Papillary Mucinous Neoplasms?: A Multi-institutional Study

The relevance of margin positivity on recurrence after resection of intraductal papillary mucinous neoplasms (IPMNs) is poorly defined and represents one reason controversy remains regarding optimal surveillance recommendations. Patients undergoing surgery for noninvasive IPMN at 8 academic medical centers from the Central Pancreas Consortium were analyzed. A positive margin was defined as presence of IPMN or pancreatic intraepithelial neoplasia. Five hundred two patients underwent surgery for IPMN; 330 (66%) did not have invasive cancer on final pathology and form the study cohort. Of these, 20% harbored high grade dysplasia. A positive margin was found in 20% of cases and was associated with multifocal disease (P = 0.02). The majority of positive margins were associated with low grade dysplasia. At a median follow-up of 36 months, 34 (10.3%) patients recurred, with 6.7% developing recurrent cystic disease and 3.6% developing invasive cancer. On multivariate analysis, margin positivity was not associated with recurrence of either IPMN or invasive cancer (P > 0.05). No association between margin status and development of recurrence at the margin was found. Only 6% of recurrences developed at the resection margin and median time to recurrence was 22 months. Of note, 18% of recurrences occurred > 5 years following surgery. Margin positivity after resection for noninvasive IPMNs is primarily due to low grade dysplasia and is not associated with developing recurrence in the remnant pancreas or at the resection margin. Long-term surveillance is required for all patients, as a significant number of recurrences developed over 5 years after the index operation

About the role of visual field defects in pure alexia

Pure alexia is an acquired reading disorder characterized by a disproportionate prolongation of reading time as a function of word length. Although the vast majority of cases reported in the literature show a right-sided visual defect, little is known about the contribution of this low-level visual impairment to their reading difficulties. The present study was aimed at investigating this issue by comparing eye movement patterns during text reading in six patients with pure alexia with those of six patients with hemianopic dyslexia showing similar right-sided visual field defects. We found that the role of the field defect in the reading difficulties of pure alexics was highly deficit-specific. While the amplitude of rightward saccades during text reading seems largely determined by the restricted visual field, other visuo-motor impairments-particularly the pronounced increases in fixation frequency and viewing time as a function of word length-may have little to do with their visual field defect. In addition, subtracting the lesions of the hemianopic dyslexics from those found in pure alexics revealed the largest group differences in posterior parts of the left fusiform gyrus, occipito-temporal sulcus and inferior temporal gyrus. These regions included the coordinate assigned to the centre of the visual word form area in healthy adults, which provides further evidence for a relation between pure alexia and a damaged visual word form area. Finally, we propose a list of three criteria that may improve the differential diagnosis of pure alexia and allow appropriate therapy recommendations