Remote-refocusing light-sheet fluorescence microscopy enables 3D imaging of electromechanical coupling of hiPSC-derived and adult cardiomyocytes in co-culture

Improving cardiac function through stem-cell regenerative therapy requires functional and structural integration of the transplanted cells with the host tissue. Visualizing the electromechanical interaction between native and graft cells necessitates 3D imaging with high spatio-temporal resolution and low photo-toxicity. A custom light-sheet fluorescence microscope was used for volumetric imaging of calcium dynamics in co-cultures of adult rat left ventricle cardiomyocytes and human induced pluripotent stem cell-derived cardiomyocytes. Aberration-free remote refocus of the detection plane synchronously to the scanning of the light sheet along the detection axis enabled fast dual-channel 3D imaging at subcellular resolution without mechanical sample disturbance at up to 8 Hz over a ∼300 µm × 40 µm × 50 µm volume. The two cell types were found to undergo electrically stimulated and spontaneous synchronized calcium transients and contraction. Electromechanical coupling improved with co-culture duration, with 50% of adult-CM coupled after 24 h of co-culture, compared to 19% after 4 h (p = 0.0305). Immobilization with para-nitroblebbistatin did not prevent calcium transient synchronization, with 35% and 36% adult-CM coupled in control and treated samples respectively (p = 0.91), indicating that electrical coupling can be maintained independently of mechanotransduction

Lithologic conditions of inundated slope defluction in river valleys of the eastern east European plain

The field stationary researches carried out within the last 30 years proved ubiquitous development of soil and ground masses sluggish movements on slopes and in the bottoms of river valleys. Speeds of these movements and their distribution are determined by slope vertical and profile. The purpose of this article is to establish dependence of similar movements on various natural factors intensity. Our own field research data confirm that the maximal speed of friable material shift is observed in clays and heavy loams, and minimum speeds of shift are typical for mild loamy structure deposits. For sand intensity of creep fades so that the size of soil peripheral speed shift is within limiting measurement accuracies. The inundated defluction study showed the shifting of top inundated alluvion depth in a lengthwise direction on the valley bottom and change of this shifting direction with depth. Average peripheral speed of upper inundated alluvion shift, according to results of the plates position concerning the profile line and the fixed reference point in the bottom of exploring shaft, changed from 0,3 to 60 mm * year-1. The maximal shift was observed near waterway bed, and minimum - at the rear seam of the bottom. Intensity of longitudinal shift is in direct dependence on biases of longitudinal profile of the river and alluvion mechanical structure. In the upper alluvion part, a loamy facies inundated alluvion, the average size of shift made 47 mm * year-1. In the bottom part the inundated alluvion within river facies the sandy structure speed decreases to 0,2-0,3 mm/year. From the depth of 1 m speed fades sharply

NMR investigations of interactions between anesthetics and lipid bilayers

Interactions between anesthetics (lidocaine and short chain alcohols) and lipid membranes formed by dimyristoylphosphatidylcholine (DMPC) were studied using NMR spectroscopy. The orientational order of lidocaine was investigated using deuterium NMR on a selectively labelled compound whereas segmental ordering in the lipids was probed by two-dimensional 1H-13C separated local field experiments under magic-angle spinning conditions. In addition, trajectories generated in molecular dynamics (MD) computer simulations were used for interpretation of the experimental results. Separate simulations were carried out with charged and uncharged lidocaine molecules. Reasonable agreement between experimental dipolar interactions and the calculated counterparts was observed. Our results clearly show that charged lidocaine affects significantly the lipid headgroup. In particular the ordering of the lipids is increased accompanied by drastic changes in the orientation of the P-N vector in the choline group

Dynamic properties of water in silicalite-1 powder

Self-diffusion of D2O in partially filled silicalite-1 crystals was studied at 25°C by 2H nuclear magnetic resonance (NMR) with bipolar field gradient pulses and longitudinal Eddy-current-delay. For the first time, reliable experimental diffusion data for this system were obtained. Analysis of NMR diffusion decays revealed the presence of a continuous distribution of apparent self-diffusion coefficients (SDCs) of water, ranging from 10-7 to ~10-10 m2/s, which include values much higher and lower than that of bulk water (~10-9 m2/s) in liquid phase. The observed distribution of SDC changes with variation of the diffusion time in the range of 10-200 ms. A two-site Kärger exchange model was successfully fitted to the data. Finally, the water distribution and exchange in silicalite-1 pores were described by taking into account (a) a gas-like phase in the zeolite pores, a gas-like phase in mesopores and an intercrystalline gas-like phase and (b) intercrystalline liquid droplets with intermediate exchange rate with the other phases. The other phases experience fast exchange on the NMR diffusion time scale. Diffusion coefficients and mean residence times of water in some of these states were estimated. © 2012 Elsevier Inc

Time-temperature superposition in viscous liquids

Dielectric relaxation measurements on supercooled triphenyl phosphite show that at low temperatures time-temperature superposition (TTS) is accurately obeyed for the primary (alpha) relaxation process. Measurements on 6 other molecular liquids close to the calorimetric glass transition indicate that TTS is linked to an $\omega^{-1/2}$ high-frequency decay of the alpha loss, while the loss peak width is nonuniversal.Comment: 4 page

ЭКСПРЕССИЯ МАРКЕРОВ CD44 И CD24 В БИОПСИЙНОМ МАТЕРИАЛЕ БОЛЬНЫХ ТРОЙНЫМ НЕГАТИВНЫМ РАКОМ МОЛОЧНОЙ ЖЕЛЕЗЫ ДО ЛЕЧЕНИЯ

The role of the expression of CD44 and CD24 in breast cancer (BC) has been explored in many laboratories around the world to identify predictive markers of tumor aggressiveness and patient’s response to anticancer therapy. These proteins participate in the process of tumor growth, metastasis and formation of cancer stem cells (CSCs). The study of CD44 and CD24 expression in triple negative (TN) BC, which is the most aggressive breast cancer subtype, is of particular interest. The aim of this study was to determine the relationship between the expression of CD44 and CD24 markers in biopsy samples of TNBC patients before treatment and clinical/ morphological characteristics of the tumors. Material and Methods. The study group included 67 patients with stage I–IV TNBC. Flow cytometry was used to determine the proportion of cells with CSC immunophenotype (CD44+/CD24-/low) in biopsy samples from the primary tumor of 65 patients and lymph nodes of 6 patients. In addition, the proportion of cells with all possible combinations of expression of these surface proteins was estimated. Results. Cells with CSC immunophenotype were detected in all patients with a wide individual variability of CSC proportion from 0.4 % to 77.0 % (median – 10.9 %). There were no differences in the proportion of CSCs in the primary tumor and lymph nodes. No statistically significant correlation between the proportion of CSCs in the primary tumor and the clinical/morphological parameters, including tumor size and differentiation grade, evidence of regional or distant metastases, tumor, size of the fraction of proliferating cells estimated by Ki67 expression, was found in either single or multivariate analysis. There was also no association of the above parameters (except Ki67) with immunophenotypes. A high proportion of Ki67-positive cells in the primary tumor was associated with the CD44-CD24-phenotype. Conclusion. The expression of CD44 and CD24 in biopsy samples of TNBC before treatment did not correlate with the clinical and morphological characteristics of the tumors, excepting Ki67 expression.Индивидуальные особенности экспрессии CD44 и CD24 при раке молочной железы (РМЖ) изучаются во многих лабораториях мира в рамках поиска прогностических маркеров агрессивности опухолевого процесса и эффективности противоопухолевой терапии, что во многом обусловлено участием этих белков в процессах опухолевого роста, метастазирования и формирования популяции опухолевых стволовых клеток (ОСК), которые составляют наиболее резистентную часть злокачественных новообразований к радиационным и многим химиотерапевтическим воздействиям. Особый интерес представляет исследование экспрессии CD44 и CD24 в случае тройного негативного (ТН) РМЖ – наиболее агрессивного среди различных молекулярных подтипов злокачественных новообразований данной локализации. Цель исследования – выяснение возможной взаимосвязи экспрессии маркеров CD44 и CD24 в биопсийном материале больных ТН РМЖ до лечения с клинико-морфологическими характеристиками опухоли. Материал и методы. В исследование включено 67 больных ТН РМЖ I–IV стадии. С помощью проточной цитометрии в биоптатах из первичного опухолевого очага 65 больных и лимфоузлов 6 больных определяли долю клеток с иммунофенотипом ОСК, которые характеризуются наличием на клеточной мембране CD44 при низкой экспрессии CD24 или отсутствии таковой (CD44+/ CD24-/low). Кроме того, оценивали долю клеток со всеми возможными комбинациями экспрессии этих поверхностных белков. Результаты. Клетки с иммунофенотипом ОСК выявлены в первичном очаге всех больных при широкой индивидуальной вариабельности их доли – от 0,4 до 77,0 % (медиана – 10,9 %). Не обнаружено различий доли ОСК в первичном очаге и в лимфоузлах. Ни при одно-, ни при многофакторном анализе не установлено значимой корреляции доли ОСК ни с одним из клинико-морфологических показателей, включая размер и степень дифференцировки опухоли, наличие регионарных и отдаленных метастазов, размер фракции пролиферирующих клеток, оцениваемый по экспрессии Ki67. Также не установлено ассоциации указанных показателей (кроме Ki67) ни с одним из преобладающих в исследованном материале иммунофенотипов. В первичном опухолевом очаге высокая доля Ki67-позитивных клеток была ассоциирована с фенотипом CD44-CD24-. Заключение. Экспрессия маркеров CD44 и CD24 в клетках биопсийного материала больных ТН РМЖ до лечения не коррелирует с клинико-морфологическими характеристиками опухоли, кроме экспрессии Ki67