Which finitely generated Abelian groups admit isomorphic Cayley graphs?

We show that Cayley graphs of finitely generated Abelian groups are rather rigid. As a consequence we obtain that two finitely generated Abelian groups admit isomorphic Cayley graphs if and only if they have the same rank and their torsion parts have the same cardinality. The proof uses only elementary arguments and is formulated in a geometric language.Comment: 16 pages; v2: added reference, reformulated quasi-convexity, v3: small corrections; to appear in Geometriae Dedicat

The effect of mastery imagery ability on appraisals and responses to psychological stress

The aim of this thesis was to investigate the effect of mastery imagery ability in regulating the appraisals and responses to stress. Following a review of the imagery and stress literature in Chapter 1, Chapter 2 consisted of an investigation on the associations between mastery imagery ability, perceived stress, general anxiety, and immediate anxiety intensity and interpretation. Chapter 2 also included an examination of whether perceived stress was a potential mechanism through which mastery imagery ability was related to anxiety. Building on the associations exhibited in Chapter 2, Chapter 3 used an experimental study design to conduct a pilot study investigating if mastery imagery ability could be increased using layered stimulus response training (LSRT), and whether increasing mastery imagery ability decreased perceived stress and general anxiety, and altered psychological appraisals and responses as well as cardiovascular responses to an acute stress task compared to a control group. Chapter 4 (i.e., the general discussion) then discussed the results found in Chapters 2 and 3 and provides avenues for future investigation. Overall, this thesis contributes to imagery and stress literature by identifying new relationships between mastery imagery ability and constructs associated with stress and coping. Findings also highlight the importance of mastery imagery ability in a non-athletic setting, and suggest that layered stimulus response training could be an effective technique to increase mastery imagery ability and subsequently lead to more adaptive coping under stress

Permeability of human red blood cell membranes to hydrogen peroxide

Resumen del Conference paper presentado a 64th Annual Meeting of the Biophysical Society, San Diego, CA. 2020Hydrogen peroxide (H2O2) and other reactive species are important physiological mediators in the vascular system. Enzymatic production of H2O2 is involved in regulating cell growth, proliferation and vasodilation. Whereas endothelial cells are important sources of H2O2, red blood cells (RBC) are considered the most important sinks of H2O2 in the vasculature. However, little is known about the permeability of their membrane to H2O2. The permeability coefficient of human RBC membranes to H2O2 was determined using the enzyme latency method, based on measuring the rate of H2O2 decomposition in lysed vs whole cells. If the passage through the membrane is the rate limiting step in H2O2 decomposition, then a difference is observed that can be used to calculate the permeability coefficient. Additional experiments were done to differentiate between simple diffusion through the lipid fraction and facilitated diffusion through protein channels. The lack of reported permeability coefficients for lipid membranes prompted us to do experiments with phospholipid-cholesterol liposome membranes that indicated that simple diffusion is a slow process. Determination of partition coefficients in different solvents mimicking different depths of the membrane indicate that the low permeability of lipid membranes to H2O2 is caused mainly by its very low solubility in the acyl region of the bilayer. The activation energy of permeation through RBC membranes suggested that protein channels were involved in facilitating H2O2 diffusion through the membrane. Inhibitors of hAQP3 and hAQP1 had no effect in H2O2 consumption rate, suggesting that other membrane proteins may be involved. Although the RBC membrane presents a significant barrier to H2O2 passage, especially in comparison with other solutes such as oxygen and nitric oxide, the permeability is still high enough to support the role of RBC as sinks of H2O2 in circulation.ANII: FMV_1_2019_15559

Intensive Outpatient Acceptance and Commitment Therapy with Exposure and Response Prevention for Adolescents

Intensive treatments for youth obsessive-compulsive disorder (OCD) are important and underresearched. This study used three adolescent cases to assess the preliminary efficacy of an intensive treatment combining acceptance and commitment therapy (ACT) with exposure and response prevention (ERP) for OCD. Participants received intensive treatment for 15 hours per week for three weeks. Assessments were collected at pre-treatment, weekly during treatment, and at posttreatment. All participants ended treatment in the mild range of OCD severity with 32-60% reductions in symptoms. Participants also reported notable improvements in psychological flexibility and ended treatment in the non-clinical range of depression, anxiety, and stress. These results indicate promise and preliminary support for the use of ACT+ERP in intensive settings for adolescents with OCD. This paper focuses on the clinical application of these techniques

Permeability of lipid membranes to hydrogen peroxide

Resumen del Conference paper presentado a SfRBM 27th Annual Conferenc

Permeability of phospholipid membranes and human red blood cell membranes to hydrogen peroxide

Resumen del Conference paper presentado a SfRBM 28th Annual ConferenceHydrogen peroxide (H2O2) is an oxygen-derived oxidant involved in multiple redox processes in the cell, ranging from physiological signaling pathways to oxidative damage reactions when it is found at higher concentrations. In the vascular system, H2O2 is metabolized mainly by red blood cells (RBC) due to their very efficient antioxidant systems and high membrane permeability. However, the information regarding H2O2 transport in the human RBC membrane is limited, as neither the exact value of the permeability coefficient (Pm) nor the permeation mechanisms are known. To explore whether H2O2 permeates through the lipid fraction or protein channels, we studied H2O2 solubility in organic solvents and its permeability in lipid membranes, in order to compare with the RBC membrane. Through measurements of partition constants, we found that H2O2 is 14 and 122000 times less soluble in octanol and hexadecane than in water, anticipating a large thermodynamic barrier to H2O2 permeation by lipid membranes. The Pm in phospholipid membranes of different compositions, determined using the catalase-latency method, varied from 4×10-4 to 5×10-3 cm s-1, at 37°C. On the other hand, in human RBC we determined a Pm of 1.6×10-3 cm s-1. After obtaining these results, we evaluated the potential role of aquaporins as H2O2 transporters by checking the effect of aquaporin inhibitors in H2O2 consumption by RBC, and also by studying H2O2 permeability in RBC devoid of either aquaporin 1 or aquaporin 3. Surprisingly, we could not detect any differences in H2O2 permeability in any case. Altogether, these results provide new information on lipid membrane permeability to H2O2 and a new value for the Pm in human RBC, which was previously unknown. Additionally, they indicate that H2O2 is not transported by aquaporins in human RBC membranes, suggesting simple diffusion or a still unidentified membrane protein as a more probable pathway.ANII: ANII: FMV_1_2019_15559

Human papillomavirus type 18 E5 oncoprotein cooperates with E6 and E7 in promoting cell viability and invasion and in modulating the cellular redox state

BACKGROUND High-risk human papillomaviruses (HR-HPVs) are the etiological agents of cervical cancer. Among them, types 16 and 18 are the most prevalent worldwide. The HPV genome encodes three oncoproteins (E5, E6, and E7) that possess a high transformation potential in culture cells when transduced simultaneously. In the present study, we analysed how these oncoproteins cooperate to boost key cancer cell features such as uncontrolled cell proliferation, invasion potential, and cellular redox state imbalance. Oxidative stress is known to contribute to the carcinogenic process, as reactive oxygen species (ROS) constitute a potentially harmful by-product of many cellular reactions, and an efficient clearance mechanism is therefore required. Cells infected with HR-HPVs can adapt to oxidative stress conditions by upregulating the formation of endogenous antioxidants such as catalase, glutathione (GSH), and peroxiredoxin (PRX). OBJECTIVES The primary aim of this work was to study how these oncoproteins cooperate to promote the development of certain cancer cell features such as uncontrolled cell proliferation, invasion potential, and oxidative stress that are known to aid in the carcinogenic process. METHODS To perform this study, we generated three different HaCaT cell lines using retroviral transduction that stably expressed combinations of HPV-18 oncogenes that included HaCaT E5-18, HaCaT E6/E7-18, and HaCaT E5/E6/E7-18. FINDINGS Our results revealed a statistically significant increment in cell viability as measured by MTT assay, cell proliferation, and invasion assays in the cell line containing the three viral oncogenes. Additionally, we observed that cells expressing HPV-18 E5/E6/E7 exhibited a decrease in catalase activity and a significant augmentation of GSH and PRX1 levels relative to those of E5, E6/E7, and HaCaT cells. MAIN CONCLUSIONS This study demonstrates for the first time that HPV-18 E5, E6, and E7 oncoproteins can cooperate to enhance malignant transformationANII: PD_NAC_2016_1_13332