Spatiotemporal Organization of Electromechanical Phase Singularities during High-Frequency Cardiac Arrhythmias

Ventricular fibrillation (VF) is a lifethreatening electromechanical dysfunction of the heart associated with complex spatiotemporal dynamics of electrical excitation and mechanical contraction of the heart muscle. It has been hypothesized that VF is driven by three-dimensional (3D) rotating electrical scroll waves, which can be characterized by filament-like electrical phase singularities (EPS). Recently, it was shown that rotating excitation waves during VF are associated with rotating waves of mechanical deformation. 3D mechanical scroll waves and mechanical filaments describing their rotational core were observed in the ventricles by using high-resolution ultrasound. The findings suggest that the spatiotemporal organization of cardiac fibrillation may be assessed from waves of mechanical deformation. However, the complex relationship between excitation and mechanical waves during VF is currently not understood. Here, we study the fundamental nature of mechanical phase singularities (MPS), their spatiotemporal organization and relation with EPS. We demonstrate the existence of two fundamental types of MPS: "paired singularities", which are co-localized with EPS, and "unpaired singularities", which can form independently. We show that the unpaired singularities emerge due to the anisotropy of the active force field, generated by fiber anisotropy in cardiac tissue, and the non-locality of elastic interactions, which jointly induce strong spatiotemporal inhomogeneities in the strain fields. The inhomogeneities lead to the breakup of deformation waves and create MPS, even in the absence of EPS, which are typically associated with excitation wave break. We exploit these insights to develop an approach to discriminate paired and unpaired MPS. Our findings provide a fundamental understanding of the complex spatiotemporal organization of electromechanical waves in the heart.Comment: 23 pager, 17 figure

Comparing the patterns of hypertension and type 2 diabetes mellitus in patients with colorectal cancer

Background: Type 2 diabetes mellitus (DM) and hypertension are worldwide epidemic. Colorectal cancer (CRC) is the most prevalent gastrointestinal cancer in Iran. Prevalence of type 2 diabetes mellitus and hypertension in the patients with colorectal cancer had not reported in Iran, before this study. Methods: Overall, 2570 individual-year follow-ups were conducted for 1127 patients with colorectal cancer. For diagnosis of type 2 diabetes mellitus, fasting blood sugar and glycosylated hemoglobin tests were used and for that of hypertension, blood pressure was measured in two turns. The descriptive indices were calculated and the mean and median survivals, from colorectal cancer diagnosis time, were calculated using survival analysis and the comparison among survival times was done through log-rank test. Stata12 software was used for data analysis. Findings: The prevalences of hypertension and type 2 diabetes mellitus in the patients with colorectal cancer were 13.38 (95 CI: 11.1-15.8) and 8.69 (95 CI: 7.0-10.7), respectively. Median survival time in patients with hypertension and diabetes mellitus were 8.52 and 4.90 years, respectively. According to log-rank test, no significant difference was observed between the survival time of patients with colorectal cancer suffering from hypertension and type 2 diabetes mellitus. Conclusion: The obtained findings in this study indicate that survival time in patients with type 2 diabetes mellitus is less than those with hypertension; but two metabolic diseases have same effect on survival rate of the patients with colorectal cancer. © 2014, Isfahan University of Medical Sciences(IUMS). All rights reserved

An early Little Ice Age brackish water invasion along the south coast of the Caspian Sea (sediment of Langarud wetland) and its wider impacts on environment and people

Caspian Sea level has undergone significant changes through time with major impacts not only on the surrounding coasts, but also offshore. This study reports a brackish water invasion on the southern coast of the Caspian Sea constructed from a multi-proxy analysis of sediment retrieved from the Langarud wetland. The ground surface level of wetland is >6 m higher than the current Caspian Sea level (at -27.41 m in 2014) and located >11 km far from the coast. A sequence covering the last millennium was dated by three radiocarbon dates. The results from this new study suggest that Caspian Sea level rose up to at least -21.44 m (i.e. >6 m above the present water level) during the early Little Ice Age. Although previous studies in the southern coast of the Caspian Sea have detected a high-stand during the Little Ice Age period, this study presents the first evidence that this high-stand reached so far inland and at such a high altitude. Moreover, it confirms one of the very few earlier estimates of a high-stand at -21 m for the second half of the 14th century. The effects of this large-scale brackish water invasion on soil properties would have caused severe disruption to regional agriculture, thereby destabilizing local dynasties and facilitating a rapid Turko-Mongol expansion of Tamerlane’s armies from the east.N Ghasemi (INIOAS), V Jahani (Gilan Province Cultural Heritage and Tourism Organisation) and A Naqinezhad (University of Mazandaran), INQUA QuickLakeH project (no. 1227) and to the European project Marie Curie, CLIMSEAS-PIRSES-GA-2009-24751

Oral consumption of α-linolenic acid increases serum BDNF levels in healthy adult humans

Background aims: Dietary omega-6 and omega-3 fatty acids have remarkable impacts on the levels of DHA in the brain and retina. Low levels of DHA in plasma and blood hamper visual and neural development in children and cause dementia and cognitive decline in adults. The level of brain-derived neurotrophic factors (BDNF) changes with dietary omega-3 fatty acid intake. BDNF is known for its effects on promoting neurogenesis and neuronal survival. Methods: In this study, we examined the effect of the oral consumption of α-Linolenic acid (ALA) on blood levels of BDNF and Malondialdehyde (MDA) in healthy adult humans. 30 healthy volunteers, 15 men and 15 women, were selected randomly. Each individual served as his or her own control. Before consuming the Flaxseed oil capsules, 5cc blood from each individual was sampled in order to measure the plasma levels of BDNF and MDA as baseline controls. During the experiment, each individual was given 3 oral capsules of flaxseed oil, containing 500mg of alpha linolenic acid, daily for one week. Then, plasma levels of BDNF and MDA were tested. Results: The plasma levels of BDNF and MDA significantly (P < 0.05) increased in individuals who received the oral capsules of ALA. Plasma levels of BDNF increased more in the women in comparison with the men. Conclusion: ALA treatment could be a feasible approach to reduce size of infarcts in stroke patients. Thus, ALA could be used in adjunction with routine stroke therapies to minimize brain lesions caused by stroke. © 2015 Hadjighassem et al.; licensee BioMed Central

Effects of adverse early-life experiences on sexually transmitted infections among homelesswomen

Background: Homeless women are at high risk of sexually transmitted infections (STIs) due to their adverse early-life experiences. Objectives: This study aimed to examine the association between adverse early-life experiences and the risk of acquiring STIsamong homeless women in Tehran. Patients and Methods: A descriptive-analytical cross-sectional study was carried out in 2014. The study recruited 241 homeless women through quota sampling from the drop in centers and shelters affiliated to a local welfare organization in Tehran, Iran. Data were obtained using questionnaires on demographics and adverse early-life experiences. Blood and urine samples were tested for human immunodeficiency virus (HIV), herpes simplex virus 2 (HSV-2), syphilis, Chlamydia trachomatis, and Neisseria gonorrhea. Descriptive statistics including frequency were calculated for all variables. To analyze the data at a significance level of 0.05, binary logistic regression was used. Results: The prevalence rates of HIV/AIDS, HSV-2, syphilis, Chlamydia trachomatis, and Neisseria gonorrhea were 8.29, 23.65, 14.93, 11.61, and 6.63, respectively. The results of logistic regression showed that the risk of acquiring STIs increases by factors such as sexual abuse (OR = 4.06; 95 CI = 1.21 -13.6, P = 0.02), running away from home (OR = 4.46; 95 CI = 1.67 -12.89, P = 0.03), drug use (OR = 3.93; 95 CI = 1.13 -13.58, P = 0.03), alcohol use (OR = 4.12; 95 CI = 1.38 -12.24, P = 0.01), imprisonment and criminal records (OR = 2.72; 95 CI = 1.01 -7.52, P = 0.04), premarital sexual activity (OR = 4.71; 95 CI = 1.06 -13.84, P = 0.05), divorce (OR = 3.47; 95 CI = 1.06 -11.32, P = 0.03), Nikah mut'ah (OR = 4.33; 95 CI = 1.39 -13.49, P = 0.01), having multiple sex partners (OR = 5.2; 95 CI = 1.81 -14.96, P = 0.02), and having unprotected sexual relationships (OR = 3.69; 95 CI = 1.00 -13.62, P = 0.05). Conclusions: Homeless women had high rates of adverse early-life experiences and overall 41.49 of them were affected at least by one STI. Future interventions should focus on the reduction of adverse early-life experiences, especially during adolescence, including the promotion of adolescent empowerment, promotion of condom use, and improvement of awareness of STIs. © 2019, Author(s)