Short-Term Cessation of Dabigatran Causes a Paradoxical Prothrombotic State.

OBJECTIVE: It is unclear if stopping treatment with dabigatran, a new oral anticoagulant (NOAC), induces a paradoxical rebound prothrombotic state. We investigated if short-term (1-3 days) dabigatran cessation is associated with a higher thrombus volume than expected from a simple reversal of the anticoagulant effect. METHODS: Ten-week-old C57Bl/6 mice (n = 338) received one of the following oral treatments: phosphate-buffered saline (PBS), dabigatran for 7 days with or without 1 to 4 day cessation, and aspirin in either a single dose or daily for 7 days. Some of the animals that ceased dabigatran for 1 to 3 days received single-dose aspirin. Thereafter, we induced FeCl3 -mediated carotid thrombosis in 130 mice, after which we performed micro computed tomography thrombus imaging. The other 208 mice underwent coagulation assays or platelet function tests. As an explorative pilot study, we reviewed the medical records of 18 consecutive patients with NOAC cessation-related cerebral infarction in a large acute stroke cohort. RESULTS: We observed a ~ 40% higher volume of carotid thrombus after dabigatran cessation at 1 to 3 days than after vehicle treatment and showed that this effect could be prevented by single-dose aspirin pretreatment. Dabigatran cessation unduly increased platelet aggregability for 2 days after drug cessation, an effect mediated through thrombin or arachidonic acid, which effect was significantly attenuated by single-dose aspirin pretreatment. In patients, short-term (≤ 3 days) cessation of NOAC therapy, compared with longer-term (≥ 5 days) cessation, tended to be associated with relatively high stroke severity. INTERPRETATION: We provide the first preclinical evidence that a rebound prothrombotic state follows short-term cessation of dabigatran therapy. ANN NEUROL 2021;89:444-458.

The in vitro cytotoxic, genotoxic, and oxidative damage potentials of the oral artificial sweetener aspartame on cultured human blood cells

Background/aim: Aspartame (APM, L-aspartyl-L-phenylalanine methylester) is a low-calorie, nonsaccharide artificial sweetener widely used in foods and beverages. When metabolized by the body, APM is broken down into aspartic acid, phenylalanine amino acids, and a third substance, methanol. Since the amino acid phenylalanine serves as a neurotransmitter building block affecting the brain, and methanol is converted into toxic formaldehyde, APM has deleterious effects on the body and brain. Thus, its safety and, toxicity have been the subjects of concern ever since it was first discovered. Although many studies have been performed on it, due to the presence of conflicting data in the literature, there are still numerous question marks concerning APM.Therefore, the safety of aspartame was tested using in vitro methods. Materials and methods: We aimed to evaluate the in vitro cytotoxic effects by using 3-(4,5-dimetylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and lactate dehydrogenase release tests, genotoxic damage potential by using chromosome aberration (CA) assay, and antioxidant/oxidant activity by using total antioxidant capacity (TAC) and total oxidative stress (TOS) analysis in primary human whole blood cell cultures. Results: The results of the MTT test showed that APM led to significant decreases in cell viability in a clear concentration-dependent manner. Moreover, an increase in CA frequency was found in the cells treated with APM. However, APM treatments did not cause any significant changes in TAC and TOS levels in whole blood cultures. Conclusion: Overall, the obtained results showed that APM had genotoxicity potential and a concentration-dependent cytotoxic activity in human blood cells.

Developmental biology meets toxicology: contributing reproductive mechanisms to build adverse outcome pathways.

An adverse outcome pathway (AOP) is a simplified description of the sequence of mechanistic events that lead to a particular toxicological effect, from initial trigger to adverse outcome. Although designed to inform regulatory risk assessors, the AOP framework also provides a platform for innovative collaborations between experts from relevant research fields and the regulatory community. The underpinning for any AOP is basic knowledge about molecular and developmental processes; such knowledge can only be attained by solid bioscientific research. Starting with this fundamental knowledge, the objective is to devise novel testing strategies that focus on key events in a causative pathway. It is anticipated that such a knowledge-based approach will ultimately alleviate many of the burdens associated with classical chemical testing strategies that typically involve large-scale animal toxicity regimens. This hails from the notion that a solid understanding of the underlying mechanisms will allow the development and use of alternative test methods, including both in vitro and in silico approaches. This review is specifically targeted at professionals working in bioscientific fields, such as developmental and reproductive biology, and aims to (i) inform on the existence of the AOP framework and (ii) encourage new cross-disciplinary collaborations. It is hoped that fundamental biological knowledge can thus be better exploited for applied purposes: firstly, an improved understanding of how our perpetual exposure to environmental chemicals is causing human reproductive disease and, secondly, new approaches to screen for harmful chemicals more efficiently. This is not an instructional manual on how to create AOPs; rather, we discuss how to harness fundamental knowledge from the biosciences to assist regulatory toxicologists in their efforts to protect humans against chemicals that harm human reproductive development and function.

Autoconcepto, actividad física y sustancias nocivas: un modelo de ecuaciones estructurales / Self-Concept, Physical Activity and Harmful Substances: A Model of Structural Equations

La presente investigación pretende definir y contrastar un modelo explicativo del consumo de alcohol y tabaco, y la práctica de actividad física en función de las cinco dimensiones del autoconcepto en una muestra de 2.134 adolescentes de la provincia de Granada (España). Los instrumentos empleados fueron el Cuestionario de Autoconcepto Forma-5, Test para la Identificación de Trastornos en el Uso de Alcohol-AUDIT, Test para la Dependencia a la Nicotina-FTND y un cuestionario ad-hoc para controlar la práctica de actividad física. En esta investigación se planteó un modelo de ecuaciones estructurales que se ajustó de forma adecuada (χ2 = 79,476; gl = 8; p = 0,000; CFI = 0,968; NFI = 0,964; IFI = 0,968; RMSEA = 0,065). Los resultados obtenidos muestran una relación positiva entre el consumo de alcohol y el consumo de tabaco, y relaciones negativas entre el autoconcepto familiar, emocional y académico con el consumo de alcohol

The present research aims to define and contrast an explanatory model of alcohol and tobacco consumption, and the practice of physical activity according to the five dimensions of self-concept in a sample of 2.134 adolescents from the province of Granada (Spain). The instruments used were the Self-concept Questionnaire Form-5, Test for the Identification of Disorders in the Use of Alcohol-AUDIT, Test for the Nicotine-FTND Unit and an ad-hoc questionnaire to control the practice of physical activity. In this research, a model of structural equations was presented that was adjusted appropriately (χ2 = 79.476, gl = 8, p = 0,000, CFI = 0,968, NFI = 0,964, IFI = 0,968, RMSEA = 0,065). The results obtained show a positive relationship between alcohol consumption and tobacco consumption, and negative relationships between family, emotional and academic self-concept with alcohol consumption

Avaliação microbiológica de queijos minas artesanais provenientes da Serra da Canastra durante e após o período de maturação / Microbiological evaluation of artisanal minas cheeses from Serra da Canastra during and after the ripening period

O queijo minas artesanal da Canastra é produzido na região da Serra da Canastra por pequenos produtores, sendo que alguns são cadastrados no Programa Queijo Minas Artesanal (PQMA) do Instituto Mineiro de Agropecuária (IMA). Por ser fabricado com leite cru, é importante que os patógenos que podem ser veiculados sejam controlados durante e após o período mínimo de maturação do queijo de 22 dias. Este trabalho avaliou as características microbiológicas de queijos obtidos de 78 produtores rurais da região da Canastra após a maturação e de três produtores rurais durante maturação. As contagens de coliformes totais, Escherichia coli e Staphylococcus coagulase positiva foram realizadas em placas Petrifilm® (3M). A detecção de Salmonella spp. foi realizada utilizando o método ISO 6579: 2002 e por PCR convencional e Listeria monocytogenes foi investigada de acordo com o método ISO 11290-1:1996/(A) 1: 2004 e PCR convencional. A contagem de Enterobacteriaceae foi determinada pelo método APHA 9.62: 2015. As mensurações de pH foram realizadas de acordo com o método IAL 017/IV em pHmetro digital BEL engineering e aferidas diretamente com pHmetro Hanna Instruments e a atividade de água (aw) em analisador Aqua Lab. No estudo realizado ao longo da maturação, as análises indicaram que as amostras, todas provenientes de produtores cadastrados no PQMA, atingiram os limites estabelecidos pela legislação antes dos 22 dias de maturação. Houve diferença significativa (p<0,05) no pH das amostras ao longo da maturação, embora este parâmetro não tenha correlação com as contagens analisadas. Já no estudo pós maturação, os resultados mostraram que 54% das amostras dos produtores cadastradas e 65% das amostras dos produtores não cadastradas no PQMA não atenderam a pelo menos um parâmetro microbiológico exigido pela legislação. As contagens obtidas para Enterobacteriaceae variaram de <1 a 6,6 log UFC/g, para coliformes totais de <1 a 6,4 log UFC/g, E. coli de <1 a 5,8 log UFC/g e Staphylococcus coagulase positiva de <1 a 7,6 log UFC/g. Em nenhuma amostra foi encontrada Salmonella spp e L. monocytogenes foi detectada e confirmada por PCR em uma amostra analisada. Os valores obtidos de pH e aw estratificados em grupos que atendem e não atendem a legislação não mostraram diferença significativa, sugerindo que esses parâmetros não são bons indicadores de qualidade microbiológica do produto. O elevado número de não-conformidades indica que são necessários esforços para melhoria das condições higiênico-sanitárias refletidas por meio dos indicadores microbiológicos. O registro no PQMA mostrou-se efetivo durante o estudo da maturação, mas não teve o mesmo resultado no estudo mais abrangente realizado pós maturação. São necessários mais esforços dos produtores (cadastrados e não cadastrados) bem como dos órgãos reguladores para melhoria dos indicadores microbiológicos

Canastra artisanal minas cheese is produced in the Serra da Canastra region by small farmers who may or may not be registered in the Artisanal Minas Cheese Program (PQMA) of the Agricultural Institute of Minas Gerais (IMA). Since this cheese is made from raw milk, it is important that the pathogens that may be carried in this product are controlled during the 22 days of ripening. This work evaluated the microbiological characteristics of cheese samples from 78 rural properties in the Canastra region after the ripening period and during ripening in three rural properties. Total coliform counts, Escherichia coli and Staphylococcus coagulase positive were performed on Petrifilm® plates (3M). The detection of Salmonella spp. was performed using the ISO 6579: 2002 method and conventional PCR and Listeria monocytogenes was investigated according to ISO 11290-1: 1996/(A) 1: 2004 and conventional PCR. The Enterobacteriaceae count was determined by the APHA method 9.62: 2015. The pH analyzes were performed according to the IAL 017/IV method on a BEL engineering digital pHmeter and measuring directly with Hanna Instruments pHmeter and the water activity (aw) in Aqua Lab analyzer. In the study carried out during ripening, the analyzes indicated that the samples, all from properties registered in the PQMA, reached the limits established by the legislation before the 22 days of ripening. There was a significant difference (p <0.05) in the pH of the samples during ripening, even though this parameter did no correlate with the microbiological counts. In the post-ripening study, the results showed that 54% of samples from PQMA registered properties and 65% of samples from non-registered properties did not comply with at least one microbiological parameter required by the legislation. Enterobacteriaceae counts ranged from <1 to 6.6 log CFU/g, for total coliforms from <1 to 6.4 log CFU/g, E. coli from <1 to 5.8 log CFU/g and Staphylococcus coagulase positive from <1 to 7.6 log CFU/g. Salmonella spp was not detected and L. monocytogenes was detected and confirmed by conventional methodology and by PCR in one analyzed sample. The pH and aw values stratified in groups that complied and did not comply with the legislation showed no significant difference, suggesting that these parameters are not good indicators of microbiological safety of the product. The high number of nonconformities indicates that efforts are needed to improve the hygiene and sanitary conditions reflected through the microbiological indicators. The PQMA registration was effective during the ripening study but did not have the same result in the larger post-ripening study. More efforts are needed from producers (registered and non-registered) as well as regulators to improve microbiological indicators of this cheese

Prediction of the Toxicity of Binary Mixtures by QSAR Approach Using the Hypothetical Descriptors.

Organic compounds are often exposed to the environment, and have an adverse effect on the environment and human health in the form of mixtures, rather than as single chemicals. In this paper, we try to establish reliable and developed classical quantitative structure⁻activity relationship (QSAR) models to evaluate the toxicity of 99 binary mixtures. The derived QSAR models were built by forward stepwise multiple linear regression (MLR) and nonlinear radial basis function neural networks (RBFNNs) using the hypothetical descriptors, respectively. The statistical parameters of the MLR model provided were N (number of compounds in training set) = 79, R² (the correlation coefficient between the predicted and observed activities)= 0.869, LOOq² (leave-one-out correlation coefficient) = 0.864, F (Fisher's test) = 165.494, and RMS (root mean square) = 0.599 for the training set, and Next (number of compounds in external test set) = 20, R² = 0.853, qext2 (leave-one-out correlation coefficient for test set)= 0.825, F = 30.861, and RMS = 0.691 for the external test set. The RBFNN model gave the statistical results, namely N = 79, R² = 0.925, LOOq² = 0.924, F = 950.686, RMS = 0.447 for the training set, and Next = 20, R² = 0.896, qext2 = 0.890, F = 155.424, RMS = 0.547 for the external test set. Both of the MLR and RBFNN models were evaluated by some statistical parameters and methods. The results confirm that the built models are acceptable, and can be used to predict the toxicity of the binary mixtures.

Acute kidney injury and 'nephrotoxins': mind your language.

The introduction of the term 'acute kidney injury' (AKI) along with an international classification scheme,1 caused some initial confusion, but most clinicians and many patients now understand that the term 'injury' denotes damage to the internal workings of the kidney, rather than physical trauma. However, of greater concern is the use of the term 'nephrotoxic' to include drugs that are, in most settings, nephroprotective. We argue that this imprecise terminology, unfortunately adopted by the National Institute for Health and Care Excellence (NICE) among others, is potentially harmful, and that the terms 'nephrotoxin' and 'nephrotoxic' should not be used to describe haemodynamically mediated and fully reversible effects of some drugs on excretory function.

Impact of toxicant exposures on ovarian gap junctions.

Ovarian gap junctions function to provide intercellular communication between ovarian cell types and are critical for proper ovarian function. Connexons are communication channels that are comprised of connexin (CX) proteins. Connexins can be regulated through endocrine signals, thus have dynamic expression throughout the estrous cycle. Not surprisingly, ovarian function is negatively affected in mouse models deficient in Cx genes; loss of Gja4 impairs folliculogenesis while ovaries devoid of Gja1 have reductions in oocyte growth. Chemicals that negatively affect ovarian function, termed ovotoxicants, can directly target Cx mRNA or protein abundance. Endocrine disrupting chemicals, medicinal drugs, pesticides, industrial chemicals, polycyclic aromatic hydrocarbons, recreational drugs and dietary components can affect Cx levels and/or function. Also, aging and obesity can impact ovarian Cx's. This review highlights what is currently known about ovotoxicant exposures that impact ovarian gap junction function as well as identifies the many gaps in our knowledge in this area of ovarian biology.

Ixonnexin from Tick Saliva Promotes Fibrinolysis by Interacting with Plasminogen and Tissue-Type Plasminogen Activator, and Prevents Arterial Thrombosis.

Tick saliva is a rich source of modulators of vascular biology. We have characterized Ixonnexin, a member of the "Basic-tail" family of salivary proteins from the tick Ixodes scapularis. Ixonnexin is a 104 residues (11.8 KDa), non-enzymatic basic protein which contains 3 disulfide bonds and a C-terminal rich in lysine. It is homologous to SALP14, a tick salivary FXa anticoagulant. Ixonnexin was produced by ligation of synthesized fragments (51-104) and (1-50) followed by folding. Ixonnexin, like SALP14, interacts with FXa. Notably, Ixonnexin also modulates fibrinolysis in vitro by a unique salivary mechanism. Accordingly, it accelerates plasminogen activation by tissue-type plasminogen activator (t-PA) with Km 100 nM; however, it does not affect urokinase-mediated fibrinolysis. Additionally, lysine analogue ε-aminocaproic acid inhibits Ixonnexin-mediated plasmin generation implying that lysine-binding sites of Kringle domain(s) of plasminogen or t-PA are involved in this process. Moreover, surface plasmon resonance experiments shows that Ixonnexin binds t-PA, and plasminogen (KD 10 nM), but not urokinase. These results imply that Ixonnexin promotes fibrinolysis by supporting the interaction of plasminogen with t-PA through formation of an enzymatically productive ternary complex. Finally, in vivo experiments demonstrates that Ixonnexin inhibits FeCl3-induced thrombosis in mice. Ixonnexin emerges as novel modulator of fibrinolysis which may also affect parasite-vector-host interactions.

Pica in Pregnancy: An Unusual Presentation.

BACKGROUND: Pica is common in pregnancy and is often felt to be benign. The following case of severe pica presenting without anemia is unusual in its presentation, laboratory findings, and treatment. CASE: A 31-year-old multiparous woman at 37 0/7 weeks of gestation presented with esophagitis and gastritis secondary to laundry detergent consumption. She had borderline anemia (hemoglobin of 11 g/dL and hematocrit of 37%, mean corpuscular volume 80%) but was severely iron-deficient (serum ferritin 7 micrograms/dL). Parenteral iron infusion was associated with dramatic resolution of her cravings within 36 hours of treatment. CONCLUSION: Pica may be related to deficient iron stores in the absence of anemia and can result in serious morbidity. Parenteral iron may be associated with rapid pica resolution in symptomatic pregnant patients.

Comprehensive review on toxicity of persistent organic pollutants from petroleum refinery waste and their degradation by microorganisms.

Control and prevention of environmental pollution has become a worldwide issue of concern. Aromatic hydrocarbons including benzene, toluene, ethyl benzene, xylene (BTEX) and polyaromatic hydrocarbons (PAHs) are persistent organic pollutants (POPs), released into the environment mainly by exploration activities of petroleum industry. These pollutants are mutagenic, carcinogenic, immunotoxic and teratogenic to lower and higher forms of life i.e. microorganisms to humans. According to the International Agency for Research on Cancer (IARC) and United States Environmental Protection Agency (U.S. EPA), Benzo[a]pyrene (BaP) is carcinogenic in laboratory animals and humans. Aromatic hydrocarbons are highly lipid soluble and thus readily absorbed from environment in gastrointestinal tract of mammals. Treatment and remediation of petroleum refinery waste have been shown either to reduce or to eliminate genotoxicity of these pollutants. Bioremediation by using microorganisms to treat this waste is showing a promising technology as it is safe and cost-effective option among various technologies tested. The main aim of this review is to provide contemporary information on variety of aromatic hydrocarbons present in crude oil (with special focus to mono- and poly-aromatic hydrocarbons), exposure routes and their adverse effects on humans. This review also provides a synthesis of scientific literature on remediation technologies available for aromatic hydrocarbons, knowledge gaps and future research developments in this field.

The unusual presentation of a burn from methyl bromide exposure: A case report and review of the literature.

Methyl bromide chemical burns are rare. Only two cases have been reported to date. The presentation of methyl bromide chemical burns is unusual. Patients with an acute exposure should be observed closely as the initial presentation can appear deceptively benign. The latency period lasts several hours prior to the development of chemical burn wounds. In this article, we review the literature on methyl bromide chemical burns and present our experience managing a patient with an extensive methyl bromide burn.

A developmental perspective on early-life exposure to neurotoxicants.

BACKGROUND: Studies of early-life neurotoxicant exposure have not been designed, analyzed, or interpreted in the context of a fully developmental perspective. OBJECTIVES: The goal of this paper is to describe the key principles of a developmental perspective and to use examples from the literature to illustrate the relevance of these principles to early-life neurotoxicant exposures. METHODS: Four principles are discussed: 1) the effects of early-life neurotoxicant exposure depend on a child's developmental context; 2) deficits caused by early-life exposure initiate developmental cascades that can lead to pathologies that differ from those observed initially; 3) early-life neurotoxicant exposure has intra-familial and intergenerational impacts; 4) the impacts of early-life neurotoxicant exposure influence a child's ability to respond to future insults. The first principle is supported by considerable evidence, but the other three have received much less attention. DISCUSSION: Incorporating a developmental perspective in studies of early-life neurotoxicant exposures requires prospective collection of data on a larger array of covariates than usually considered, using analytical approaches that acknowledge the transactional processes between a child and the environment and the phenomenon of developmental cascades. CONCLUSION: Consideration of early-life neurotoxicant exposure within a developmental perspective reveals that many issues remain to be explicated if we are to achieve a deep understanding of the societal health burden associated with early-life neurotoxicant exposures.

[Investigation of the liver DNA methylation profile of rats under the influence of hepatotoxicants of different nature].

The functional importance of DNA methylation, which is a special case of epigenetic variation, is meant for regulation of many biological processes, ranged from tissue specific gene expression to remodeling of chromatin structure. Disorders of the DNA methylation can cause changes in the cell's phenotype, providing a significant impact on the development of pathology. Both exogenous and endogenous factors are able to cause disruption of DNA methylation, while epigenetic changes usually precede the emergence of clinical and morphological symptoms of pathological process development, consequently the parameters of DNA methylation can be used as sensitive biomarkers to detect adverse effects on the organism. The purpose of the study was to identify genes of the liver, the methylation profile of which changes under the influence of hepatotoxicants of different nature. The experiment was carried out on 60 male Wistar rats with initial body weight (b.w.) 83.3±1.5 g. Animals were randomly divided into 6 groups - 1 control and 5 test groups, with 10 rats in each group. During the first two weeks of the experiment the rats of the 1-5th test groups were administered to aflatoxin B1 (200 Mg/kg b.w.), cadmium chloride 2,5-hydrate (2 mg/kg), monosodium glutamate (1000 mg/kg), epigallocatechin gallate (EGCG) (1000 mg/kg), paracetamol (150 mg/kg), accordingly. Methylation of the liver genes in rats was determined by using high-performance methods, based on bisulfite sequencing of reduced representation. For each sample from 12 to 30 million pairs of reads were received, genes which demonstrated significant changes in methylation when exposed to toxic factors were identified: aflatoxin B1 caused changes in the methylation of 57 genes; cadmium - 54 genes; monosodium glutamate - 39 genes; EGCG -198 genes; paracetamol - 167 genes. The comparison of genes with altered methylation in the experimental groups revealed that none of the genes repeatedly occurred under the influence of each toxicant out of five, the highest number of repeats accounted 3. As a result of the present analysis 7 genes have been selected: methylation change in Fan1 gene was observed when exposed to cadmium, monosodium glutamate, EGCG; gene Lppr2 - under the influence of aflatoxin B1, EGCG, paracetamol; gene Mlh3 - under the influence of aflatoxin B1, cadmium, paracetamol; Sirt7 gene - under the influence of cadmium, EGCG, paracetamol; gene Fbxo15 - when exposed to cadmium, monosodium glutamate, paracetamol; gene E2f1 - when exposed to cadmium, EGCG, paracetamol; gene Mrps16 - when exposed to cadmium, EGCG, paracetamol. On the basis of the received data the project of the panel of genes-biomarkers of toxic effect, including genes Fan1, Lppr2, Mlh3, Sirt7, Fbxo15, E2f1, Mrps16 has been formed.

Pistacia Terebinthus Coffee Protects against Thioacetamide-Induced Liver Injury in Rats.

AIM/BACKGROUND: Pistacia terebinthus is used as a coffee substitute in the East and Southern Anatolia regions of Turkey. It contains unsaturated fatty acids, tocopherols, polyphenols and carotenoids. P. terebinthus has anti-inflammatory and potential antioxidant activity. In this study we evaluated the protective effects of P. terebinthus coffee (PTC) on thioacetamide (TAA)-induced liver injury in rats. MATERIALS AND METHODS: Twenty-eight male Sprague-Dawley rats were equally randomized into four groups. Chronic liver injury was induced with TAA (100 mg/kg i.p. three times weekly). The first group of rats served as control and received only tap water (G1), and the remaining groups of rats received PTC, p.o (G2); TAA (G3); TAA plus PTC, p.o (G4), respectively. RESULTS: After 8 weeks, PTC intake significantly reduced fibrosis/inflammation scores (p PTC intake reduced transforming growth factor beta (TGF-ß) concentrations in the liver (p PTC intake. DISCUSSION AND CONCLUSION: PTC intake provided beneficial effects against TAA-induced liver injury in rats. PTC probably suppresses the proinflammatory cytokines through NF-κB signaling pathway.

Label-retaining, quiescent globose basal cells are found in the olfactory epithelium.

The vertebrate olfactory epithelium (OE) is known for its ability to renew itself throughout life as well as to reconstitute after injury. Although this remarkable capacity demonstrates the persistence of stem cells and multipotent progenitor cells, their nature in the OE remains undefined and controversial, as both horizontal basal cells (HBCs) and globose basal cells (GBCs) have features in common with each other and with stem cells in other tissues. Here, we investigate whether some among the population of GBCs satisfy a key feature of stem cells, i.e., mitotic quiescence with retention of thymidine analogue label and activation by injury. Accordingly, we demonstrate that some GBCs express p27(Kip1) , a member of the Kip/Cip family of cyclin-dependent kinase inhibitors. In addition, some GBCs retain bromodeoxyuridine or ethynyldeoxyuridine for an extended period when the pulse is administered in neonates followed by a 1-month chase. Their identity as GBCs was confirmed by electron microscopy. All spared GBCs express Ki-67 in the methyl bromide (MeBr)-lesioned OE initially after lesion, indicating that the label-retaining (LR) GBCs are activated in response to injury. LR-GBCs reappear during the acute recovery period following MeBr exposure, as demonstrated with 2- or 4-week chase periods after labeling. Taken together, our data demonstrate the existence of LR-GBCs that are seemingly activated in response to epithelial injury and then re-established after the initial phase of recovery is completed. In this regard, some among the GBCs satisfy a common criterion for functioning like stem cells.

Functional expression of the transient receptor potential channel TRPA1, a sensor for toxic lung inhalants, in pulmonary epithelial cells.

The cation channel TRPA1 functions as a chemosensory protein and is directly activated by a number of noxious inhalants. A pulmonary expression of TRPA1 has been described in sensory nerve endings and its stimulation leads to the acceleration of inflammatory responses in the lung. Whereas the function of TRPA1 in neuronal cells is well defined, only few reports exist suggesting a role in epithelial cells. The aim of the present study was therefore (1) to evaluate the expression of TRPA1 in pulmonary epithelial cell lines, (2) to characterize TRPA1-promoted signaling in these cells, and (3) to study the extra-neuronal expression of this channel in lung tissue sections. Our results revealed that the widely used alveolar type II cell line A549 expresses TRPA1 at the mRNA and protein level. Furthermore, stimulating A549 cells with known TRPA1 activators (i.e., allyl isothiocyanate) led to an increase in intracellular calcium levels, which was sensitive to the TRPA1 blocker ruthenium red. Investigating TRPA1 coupled downstream signaling cascades it was found that TRPA1 activation elicited a stimulation of ERK1/2 whereas other MAP kinases were not affected. Finally, using epithelial as well as neuronal markers in immunohistochemical approaches, a non-neuronal TRPA1 protein expression was detected in distal parts of the porcine lung epithelium, which was also found examining human lung sections. TRPA1-positive staining co-localized with both epithelial and neuronal markers underlining the observed epithelial expression pattern. Our findings of a functional expression of TRPA1 in pulmonary epithelial cells provide causal evidence for a non-neuronal TRPA1-mediated control of inflammatory responses elicited upon TRPA1-mediated registration of toxic inhalants in vivo.

Occupational causes of male infertility.

PURPOSE OF REVIEW: To highlight and discuss the new evidence on occupational and environmental risk to male reproductive function. RECENT FINDINGS: Semen quality following occupational exposure to boron (an acknowledged experimental reproductive toxicant) and benzene, and new evidence on low-level environmental exposure to widespread xenobiotics with endocrine actions. SUMMARY: The naturally occurring semimetal boron is an experimental reproductive toxicant, but now a Turkish semen study corroborates earlier evidence that high-level occupational exposure is not toxic to human spermatogenesis. It seems that human exposure levels are below the levels that cause reproductive toxicity in rodents. On the contrary, there is now ample evidence that the carcinogenic substance benzene may cause chromosomal aberrations in sperm at very low exposure levels. This includes chromosomal deletions that are known to cause infertility, mental retardation and congenital malformations. This research highlights the need to scrutinize the chemicals for possible male-mediated developmental toxicity. Several occupational studies are addressing adult testicular function in men exposed to chemicals that may interfere with endocrine signalling such as bisphenol A and phthalates, but findings are rather inconsistent and it remains to be established whether these widespread chemicals have any impact on male fertility.

[What is a "poison"? Proposal of definition]. / ¿Qué es un «tóxico¼? Una propuesta de definición.

We discuss different interpretations of the term poison as well as the need of bringing up to date the changes in this matter according to the science progress. A clear and exact definition is proposed after analysing the factors that affect the relativity of the concept and its boundaries. The proposal for a definition is presented taking into account the most broadly extended concepts concerning its significance. That is to say: "a poison is, for human beings and their non-pathogenic and non-harmful biological environment, an electromagnetic or corpuscular radiation, or a non-infectious chemical agent, structured no larger in size than a small particle or fibre that, after being generated internally or after contact, penetration and/or absorption by a live organism, in sufficiently high dose, can produce or produces a direct or indirect adverse effect unrelated to its temperature or measurable electrical potential difference". The scientific knowledge needs accurate definitions to avoid ambiguities.