Biochemistry of malaria parasite infected red blood cells by X-ray microscopy

Red blood cells infected by the malaria parasite Plasmodium falciparum are correlatively imaged by tomography using soft X-rays as well as by scanning hard nano-X-ray beam to obtain fluorescence maps of various elements such as S and Fe. In this way one can deduce the amount of Fe bound either in hemoglobin or in hemozoin crystals in the digestive vacuole of the malaria parasite as well as determine the hemoglobin concentrations in the cytosols of the red blood cell and of the parasite. Fluorescence map of K shows that in the parasite's schizont stage the K concentration in the red blood cell cytosol is diminished by a factor of seven relative to a pristine red blood cell but the total amount of K in the infected red blood cell is the same as in the pristine red blood cell

ОЦЕНКА ЛИМФАТИЧЕСКОГО ОТЕКА НИЖНИХ КОНЕЧНОСТЕЙ ПО ДАННЫМ КОМПЬЮТЕРНОЙ ТОМОГРАФИИ

Lymphedema is a common disease, it is estimated that up to 10% of the population has it in varying degrees. Thus different methods are using in evaluating patients with lymphedema. Computed tomography allows to assess the condition and thickness of various layers of soft tissues, edema spread along the length of the limb and deeper spaces, objectify degree of edema and fibrotic changes in the skin and subcutaneous tissue, to obtain quantitative data of tissue density at any level and level of the limb. Comparison of clinical stage and CT data is not fully studied question. We examined 24 patients, made physical examination and lower limb MSCT. It was found that with an increase of the degree of edema increases limb volume, thickness of subcutaneous fat, increases the X-ray density of subcutaneous adipose tissue due to its edema and fibrosis. Thus, the use of MSCT saves physician's time for examination of patients with lymphedema and allows him to select the optimal treatment strategy.Лимфатический отек является широко распространенным заболеванием, считается, что до 10% населения подвержены ему в той или иной степени. При этом при оценке больных с лимфатическим отеком применяются разнообразные методики. Компьютерная томография позволяет оценить состояние и толщину различных слоев мягких тканей, распространение отека по длине конечности и в подфасциальные пространства, объективизировать степень отека и фиброзных изменений в коже и подкожной клетчатке, получить количественные данные о плотности тканей на любом уровне и участке конечности. Недостаточно изученным является вопрос сопоставления клинической стадии и данных компьютерной томографии. Обследованы 24 пациента, проводился физикальный осмотр и МСКТ нижних конечностей. Установлено, что с нарастанием степени отека увеличиваются объем конечности, толщина подкожной жировой клетчатки, возрастает рентгеновская плотность подкожной жировой клетчатки за счет ее отека и фиброзных изменений. Таким образом, применение МСКТ экономит время врача на обследование больных лимфедемой и позволяет выбрать оптимальную тактику лечения

Malaria pigment crystals as magnetic micro-rotors: Key for high-sensitivity diagnosis

The need to develop new methods for the high-sensitivity diagnosis of malaria has initiated a global activity in medical and interdisciplinary sciences. Most of the diverse variety of emerging techniques are based on research-grade instruments, sophisticated reagent-based assays or rely on expertise. Here, we suggest an alternative optical methodology with an easy-to- use and cost-effective instrumentation based on unique properties of malaria pigment reported previously and determined quantitatively in the present study. Malaria pigment, also called hemozoin, is an insoluble microcrystalline form of heme. These crystallites show remarkable magnetic and optical anisotropy distinctly from any other components of blood. As a consequence, they can simultaneously act as magnetically driven micro-rotors and spinning polarizers in suspensions. These properties can gain importance not only in malaria diagnosis and therapies, where hemozoin is considered as drug target or immune modulator, but also in the magnetic manipulation of cells and tissues on the microscopic scale

Label-free cell separation and sorting in microfluidic systems

Cell separation and sorting are essential steps in cell biology research and in many diagnostic and therapeutic methods. Recently, there has been interest in methods which avoid the use of biochemical labels; numerous intrinsic biomarkers have been explored to identify cells including size, electrical polarizability, and hydrodynamic properties. This review highlights microfluidic techniques used for label-free discrimination and fractionation of cell populations. Microfluidic systems have been adopted to precisely handle single cells and interface with other tools for biochemical analysis. We analyzed many of these techniques, detailing their mode of separation, while concentrating on recent developments and evaluating their prospects for application. Furthermore, this was done from a perspective where inertial effects are considered important and general performance metrics were proposed which would ease comparison of reported technologies. Lastly, we assess the current state of these technologies and suggest directions which may make them more accessible

Structure and formation of synthetic hemozoin: Insights from first-principles calculations

Malaria, an infectious disease once considered eradicated, has reemerged in recent years, primarily due to parasite resistance to commonly used synthetic antimalarial drugs. These drugs act by inhibiting crystallization of the malaria pigment, hemozoin (HZ). Thus, there is a vital need for understanding the process of HZ nucleation. In a companion paper, the pseudopolymorphic behavior of β-hematin, the synthetic form of HZ, has been characterized by X-ray diffraction (XRD) (Straasø, T.; Kapishnikov, S.; Kato, K.; Takata, M.; Als-Nielsen, J.; Leiserowitz, L.Cryst. Growth Des. 2011, 11, DOI: 10.1021/cg200410b). Here, we employ van der Waals (vdW)-corrected density functional theory (DFT) to study the two β-hematin crystal structures and their repeat unit, a heme dimer. We find that vdW interactions play a major role in the binding of the heme dimer and the β-hematin crystal. In addition, accounting for the periodic nature of the system is essential to obtaining the correct geometry of the heme dimer, which is affected by vdW interactions with adjacent dimers in the β-hematin crystal. The different stereoisomers of the heme dimer and their molecular crystals are close in energy, which is consistent with pseudopolymorphism in β-hematin, in agreement with recent XRD experiments. Finally, we use our results to comment on β-hematin crystallization mechanisms. This work demonstrates the viability of vdW-corrected DFT as a tool for gaining valuable insight into pertinent problems involving biological systems. © 2011 American Chemical Society