Direct Observation of Single Amyloid-β(1-40) Oligomers on Live Cells: Binding and Growth at Physiological Concentrations

Understanding how amyloid-β peptide interacts with living cells on a molecular level is critical to development of targeted treatments for Alzheimer's disease. Evidence that oligomeric Aβ interacts with neuronal cell membranes has been provided, but the mechanism by which membrane binding occurs and the exact stoichiometry of the neurotoxic aggregates remain elusive. Physiologically relevant experimentation is hindered by the high Aβ concentrations required for most biochemical analyses, the metastable nature of Aβ aggregates, and the complex variety of Aβ species present under physiological conditions. Here we use single molecule microscopy to overcome these challenges, presenting direct optical evidence that small Aβ(1-40) oligomers bind to living neuroblastoma cells at physiological Aβ concentrations. Single particle fluorescence intensity measurements indicate that cell-bound Aβ species range in size from monomers to hexamers and greater, with the majority of bound oligomers falling in the dimer-to-tetramer range. Furthermore, while low-molecular weight oligomeric species do form in solution, the membrane-bound oligomer size distribution is shifted towards larger aggregates, indicating either that bound Aβ oligomers can rapidly increase in size or that these oligomers cluster at specific sites on the membrane. Calcium indicator studies demonstrate that small oligomer binding at physiological concentrations induces only mild, sporadic calcium leakage. These findings support the hypothesis that small oligomers are the primary Aβ species that interact with neurons at physiological concentrations

КЛИНИЧЕСКИЕ И ЭПИДЕМИОЛОГИЧЕСКИЕ ЗАКОНОМЕРНОСТИ ВЕТРЯНОЙ ОСПЫ У ВЗРОСЛЫХ В ПРИМОРСКОМ КРАЕ

Objective: to establish clinical and epidemiological patterns of chickenpox in adults in the Primorsky Territory to improve treatment and prevention work. Materials and methods: The study used statistics on the incidence of chicken pox in the Primorsky Territory from 2009 to 2017 and demographic data on the population for the specified period. A clinical characteristic of 102 cases of varicella in patients hospitalized in the infectious disease ward of Primorsky Regional Clinical Hospital No. 2 (Vladivostok) in 2015-2017 is given. Results: From 2009 to 2017, the incidence of chickenpox in the Primorsky Territory was consistently high, with an average of 636.2 per 100,000 population. Analysis of the structure of patients showed that the maximum proportion of cases of chicken pox occur in organized children 3-6 years old (55.9%), schoolchildren (19.1%) and children 1–2 years old (11.6%). The proportion of 15–17 year olds was 3.0%. Adults, from 18 years old – 4.9%. The proportion of unorganized children 3–6 years old (2.9%) and children in the first year of life (2.6%) is not high. High risk of infection was detected in Vladivostok (57.8 per 100.000), Yakovlevsky (52.1% ooo), Olginsky (45.9% ooo), Lazovsky (42.8% ooo) and Shkotovsky (40, 2% ooo) areas. In the annual dynamics, a pronounced spring-summer seasonal rise was formed. The clinical course of varicella in the group of adults was characterized by an average duration of the initial period of the disease of 1.4 ± 0.7 days. For clinical diagnosis, an important time was the appearance of the rash, which varied within four days. The phenomenon of “spillage” was noted in 97% of patients. The rash was polymorphic, with the formation of crusts. The period of height was characterized by the presence of catarrhal manifestations. The granularity of the posterior pharyngeal wall was observed in all patients without exception. In 84.3% of patients there was a bright hyperemia of the pharynx. In 14.7% of cases, enantema was detected on the soft palate, palatine arches, and posterior pharyngeal wall. Dry cough was detected in 28 of 103 patients, which probably increased their epidemiological significance. Findings: The clinical picture of varicella was typical and was represented by a combination of intoxication, exanthema, and catarrhal syndrome. The epidemic process of varicella in adults in Primorsky Krai was characterized by relative autonomy of manifestations in adults, children up to one year old, and unorganized children. When implementing chickenpox epidemiological surveillance, priority should be given to interventions in epidemic foci.Цель: установление клинических и эпидемиологических закономерностей ветряной оспы у взрослых в Приморском крае для совершенствования лечебной и профилактической работы. Материалы и методы: в исследовании использованы статистические данные по заболеваемости ветряной оспой в Приморском крае с 2009 по 2017 г. и демографические данные по численности населения за указанный период. Дана клиническая характеристика 102 случаев ветряной оспы у пациентов, госпитализированных в инфекционное отделение Приморской краевой клинической больницы №2 (г. Владивосток) в 2015–2017 гг. Результаты: с 2009 по 2017 г. заболеваемость ветряной оспой в Приморском крае была стабильно высокой, со средним уровнем 636,2 на 100 000 населения. Анализ структуры больных показал, что максимальная доля случаев ветряной оспы приходится на организованных детей 3–6 лет (55,9%), школьников (19,1%) и детей 1–2 лет (11,6%). Доля лиц 15–17 лет составила 3,0%; взрослых (с 18 лет) – 4,9%. Невысока доля неорганизованных детей 3–6 лет (2,9%) и детей первого года жизни (2,6%). К территориям риска по заболеваемости ветряной оспой взрослых были отнесены Владивосток (57,8 на 100,000), Яковлевский (52,1%ooo), Ольгинский (45,9%ooo), Лазовский (42,8%ooo) и Шкотовский (40,2%ooo) районы. В годовой динамике формировался ярко выраженный весенне-летний сезонный подъем. Клиническое течение ветряной оспы в группе взрослых лиц характеризовалось средней продолжительностью начального периода болезни 1,4±0,7 дня. Для клинической диагностики важным являлось время появления сыпи, варьировавшее в пределах 4 суток. Феномен «подсыпания» был отмечен у 97% больных. Сыпь была полиморфной, с образованием корочек. Период разгара характеризовался наличием катаральных проявлений. Зернистость задней стенки глотки наблюдалась у всех без исключения пациентов. У 84,3% больных отмечалась яркая гиперемия зева. В 14,7% случаев выявлена энантема на мягком небе, небных дужках, задней стенке глотки. Сухой кашель выявлен у 28 из 102 больных, что, вероятно, увеличивало их эпидемиологическую значимость.Выводы: клиническая картина ветряной оспы была типичной и представлена сочетанием интоксикационного, экзантемного и катарального синдрома. Эпидемический процесс ветряной оспы у взрослых в Приморском крае характеризовался относительной автономностью проявлений у взрослых, детей до 1 года и неорганизованных детей. При осуществлении эпидемического надзора за ветряной оспой следует отдавать приоритет мероприятиям в эпидемических очагах

Mitochondrial Ca2+ Overload Underlies Aβ Oligomers Neurotoxicity Providing an Unexpected Mechanism of Neuroprotection by NSAIDs

Dysregulation of intracellular Ca2+ homeostasis may underlie amyloid β peptide (Aβ) toxicity in Alzheimer's Disease (AD) but the mechanism is unknown. In search for this mechanism we found that Aβ1–42 oligomers, the assembly state correlating best with cognitive decline in AD, but not Aβ fibrils, induce a massive entry of Ca2+ in neurons and promote mitochondrial Ca2+ overload as shown by bioluminescence imaging of targeted aequorin in individual neurons. Aβ oligomers induce also mitochondrial permeability transition, cytochrome c release, apoptosis and cell death. Mitochondrial depolarization prevents mitochondrial Ca2+ overload, cytochrome c release and cell death. In addition, we found that a series of non-steroidal anti-inflammatory drugs (NSAIDs) including salicylate, sulindac sulfide, indomethacin, ibuprofen and R-flurbiprofen depolarize mitochondria and inhibit mitochondrial Ca2+ overload, cytochrome c release and cell death induced by Aβ oligomers. Our results indicate that i) mitochondrial Ca2+ overload underlies the neurotoxicity induced by Aβ oligomers and ii) inhibition of mitochondrial Ca2+ overload provides a novel mechanism of neuroprotection by NSAIDs against Aβ oligomers and AD

2020 Clinical practice guidelines for Pulmonary hypertension, including chronic thromboembolic pulmonary hypertension

Russian Society of Cardiology (RSC)With the participation: Association of Cardiovascular Surgeons of Russia, Russian Respiratory Society, Federation of Anesthesiologists and Resuscitators, Association of Rheumatologists of Russia, National Congress of Radiation Diagnosticians

Unprecedented within-species chromosome number cline in the Wood White butterfly Leptidea sinapis and its significance for karyotype evolution and speciation

Background: Species generally have a fixed number of chromosomes in the cell nuclei while between-species differences are common and often pronounced. These differences could have evolved through multiple speciation events, each involving the fixation of a single chromosomal rearrangement. Alternatively, marked changes in the karyotype may be the consequence of within-species accumulation of multiple chromosomal fissions/fusions, resulting in highly polymorphic systems with the subsequent extinction of intermediate karyomorphs. Although this mechanism of chromosome number evolution is possible in theory, it has not been well documented. Results: We present the discovery of exceptional intraspecific variability in the karyotype of the widespread Eurasian butterfly Leptidea sinapis. We show that within this species the diploid chromosome number gradually decreases from 2n = 106 in Spain to 2n = 56 in eastern Kazakhstan, resulting in a 6000 km-wide cline that originated recently (8,500 to 31,000 years ago). Remarkably, intrapopulational chromosome number polymorphism exists, the chromosome number range overlaps between some populations separated by hundreds of kilometers, and chromosomal heterozygotes are abundant. We demonstrate that this karyotypic variability is intraspecific because in L. sinapis a broad geographical distribution is coupled with a homogenous morphological and genetic structure. Conclusions: The discovered system represents the first clearly documented case of explosive chromosome number evolution through intraspecific and intrapopulation accumulation of multiple chromosomal changes. Leptidea sinapis may be used as a model system for studying speciation by means of chromosomally-based suppressed recombination mechanisms, as well as clinal speciation, a process that is theoretically possible but difficult to document. The discovered cline seems to represent a narrow time-window of the very first steps of species formation linked to multiple chromosomal changes that have occurred explosively. This case offers a rare opportunity to study this process before drift, dispersal, selection, extinction and speciation erase the traces of microevolutionary events and just leave the final picture of a pronounced interspecific chromosomal difference