Diagnosis of periarticular osteoporosis in rheumatoid arthritis using digital X-ray radiogrammetry

Osteoporosis can manifest in two ways in rheumatoid arthritis: generalized bone loss, which may result from immobility, the inflammatory process per se and/or treatments such as steroids; and periarticular demineralization, which is probably due to local release of inflammatory agents. Digital X-ray radiogrammetry (DXR) is an effective and sensitive modality for monitoring periarticular osteoporosis, which is among the earliest features of rheumatoid arthritis, preceding bone erosions. DXR is a promising technique, which can provide quantitative data that allow early diagnosis. During the course of rheumatoid arthritis it can be deployed in combination with established X-ray scoring methods to inform decisions regarding the optimal therapy to prevent joint destruction.     

Structural research on the membranes and adjacent layers of erythrocytes during the production of erythrocyte ghosts

Using the polarization microscopy and X-ray crystal analysis it has been shown that the ordered structure is destroyed in membranes and adjacent layers of erythrocytes in the course of erythrocyte ghost preparation. These changes are accompanied by quenching of the birefringence which completely disappears in erythrocytes ghosts. The intensities of reflections in X-ray patterns are essentially decreased and the interlayer distances are changed.     

X-ray study in the diagnosis of traumatic mediastinitis and its complications

The study was based on the clinical and X-ray analysis of 68 patients treated at the Thoracoabdominal Surgery, N.V. Sklifosovsky Research Institute of Emergency Care, in 1992-1997. The paper gives pre- and postoperative X-ray findings of patients with mediastinitis. It shows it possible to define the precise location of a mediastinal inflammatory process, its severity and possible complications. The X-ray symptomatology of mediastinitis is presented according to the location and developmental stage of a mediastinal process. Jointly with surgeons, the authors have developed a procedure for X-ray examination of patients in the postoperative period, which involves the study of the course of the disease and the evaluation of the adequacy of performed treatment. The paper analyzes the most specific and severe complications of traumatic mediastinitis. Special emphasis is laid on the fact that during control X-ray studies it is important to keep the procedure that permits timely diagnosis of complications at different developmental stages of mediastinitis.     

Functional Flexibility of the Transketolase Molecule

Transketolase is the simplest representative of the thiamine diphosphate-dependent enzymes. It was the first of these enzymes for which X-ray analysis was performed. Based on the data of X-ray studies and using the mutagenesis technique, the nature of functional groups of the enzyme involved in the interaction with substrates and cofactors and in the coenzyme activation was defined. Thus, considerable achievements have been made in studying the structure of transketolase. However, there is relatively little information on the conformational flexibility of the enzyme molecule while it is functioning, i.e., during its interaction with cofactors and substrates and in the course of intermediate product formation. This review summarizes mainly the results obtained in the author's group, as well as those rare data on this subject that could be found in literature.     

一种新的放射治疗计划优化方法

在采用多射线束的放射治疗中,治疗计划优化是一个重要的步骤。本文描述了一种新的治疗计划优化方法。它是基于治疗医理由对治疗过程中各因素的综合考虑,弥补了传统方法的不足,具有较高的准确性。     

Low-angle x-ray diffraction of the erythrocyte membrane

Using low-angle X-ray diffraction technique it has been shown that preparing procedures can induce the phase separation in red blood cell membranes in the course of which proteins are removed from lipid bilayers. The latter form rather extensive regions and the diffraction pattern of asymmetric type changes to a symmetric one.     

Study of the implosion characteristics of quasi-spherical wire arrays on the Angara-5-1 facility at currents of up to 4 MA

Results are presented from experimental studies of the spatial distribution of the density of matter in the central part of the discharge gap and the formation of the temporal profile of the X-ray power in the course of implosion of quasi-spherical wire arrays at discharge currents of up to 4 MA. The spatial distribution of the X-ray intensity in the central part of the discharge gap and the temporal profile of the X-ray power are used as implosion characteristics of quasi-spherical wire arrays. The quasi-spherical arrays were formed by the radial stretching of unstrained wires of initially cylindrical and conical wire arrays under the action of the electrostatic field. The temporal profile of the output X-ray pulse in the photon energy range of 0.1–1 keV is shown to depend on both the geometrical parameters of the quasi-spherical array and the longitudinal distribution of its mass. It is found that a 40% increase in the wire mass due to deposition of an additional mass in the equatorial region of a quasi-spherical array leads to a 15% increase in the average current radius of the pinch and a 30% decrease in the X-ray yield. Experiments with quasi-spherical arrays made of kapron fibers with deposited Al and Bi conducting layers were also carried out. It is demonstrated that application of such arrays makes it possible to control the profile and duration of the generated X-ray pulse by varying the mass, material, and location of the deposited layer. It is found that deposition of an additional mass in the form of a thin Bi stripe on tungsten wires near the cathode end of the array allows one to mitigate the influence of the cathode zipper effect on the pinch compression and formation of the X-ray pulse in tungsten arrays.     

IEC 61267: Feasibility of type 1100 aluminium and a copper/aluminium combination for RQA beam qualities

In the course of performance acceptance testing, benchmarking or quality control of X-ray imaging systems, it is sometimes necessary to harden the X-ray beam spectrum. IEC 61267 specifies materials and methods to accomplish beam hardening and, unfortunately, requires the use of 99.9% pure aluminium (Alloy 1190) for the RQA beam quality, which is expensive and difficult to obtain. Less expensive and more readily available filters, such as Alloy 1100 (99.0% pure) aluminium and copper/aluminium combinations, have been used clinically to produce RQA series without rigorous scientific investigation to support their use. In this paper, simulation and experimental methods are developed to determine the differences in beam quality using Alloy 1190 and Alloy 1100. Additional simulation investigated copper/aluminium combinations to produce RQA5 and outputs from this simulation are verified with laboratory tests using different filter samples. The results of the study demonstrate that although Alloy 1100 produces a harder beam spectrum compared to Alloy 1190, it is a reasonable substitute. A combination filter of 0.5 mm copper and 2 mm aluminium produced a spectrum closer to that of Alloy 1190 than Alloy 1100 with the added benefits of lower exposures and lower batch variability.     

Artificial contrasting of the hip joint in children and adolescents: X-ray anatomic study

The diagnostic capacities of currently available radiation diagnostic techniques in imaging some anatomic structures of the hip joint (HJ) were determined on the basis of studies of 70 sectional sets of HJs in children and adolescents aged 0 to 13 years through X-ray and anatomic comparisons. Magnetic resonance imaging (MRI) is the method of choice in visualizing the cartilaginous and soft-tissue structures of HJ in children and adolescents. MR-arthrography extends the capacities of the technique in imaging the articular surfaces and intraarticular structures of the joint. Contrast enhancement of the HJ cavity during X-ray study and computed tomography may be an alternative to MRI as it makes it possible to well visualize the cartilaginous head of the femur, the cartilaginous borders of the cotyloid cavity, the limbus, etc. Double contrasting enhances the capacities of detailed imaging of the articular surfaces, intraarticular structures, capsules, and ligamentous apparatus of HJ. The studies performed have specified the time course of anatomic changes during HJ growth and defined the method of choice or an alternative procedure of radiation techniques in the diagnosis of these changes, which is of great importance for early detection of pathological changes and for choice of therapeutic and diagnostic policy.     

Effect of muscle storage and stimulation on the intensity of Z-reflection of its equatorial x-ray pattern

The maintenance of frog sartorius muscle in Ringer solution over a long period of time (24 h or more) increases Z-reflection intensity of equatorial X-ray pattern relative to that from fresh (1-2 h) dissecting muscle at sarcomere length more than 2.3 m. Long stimulation deteriorates the equatorial X-ray pattern from muscle. Then with the course of time Z-reflection intensity increases several times, Z and reflections merge, and rigor equatorial X-ray pattern is registered.     

X-ray microtomography for imaging of developing spiders inside egg cocoons

Embryogenesis is especially sensitive to external factors. The changes in its course are often used as biomarkers of environmental impact. Since spider embryogenesis takes place inside cocoons, it is crucial to find a reliable tool to analyze this developmental phase with no intrusion into the cocoons. The aim of this study was to verify the efficacy of X-ray microtomography for non-invasive analysis of embryonic morphology and egg quantity in the cocoons of Xerolycosa nemoralis and Agelena labyrinthica from polluted and reference sites. X-ray microtomography slice images as well as 3D images and animations obtained from digital visualization of those slides were used to study the morphology of embryos and egg arrangement in the cocoons. Any disorders in embryogenesis or malformation of embryos in relation to site of origin have not been found, but inside an egg cocoon of X. nemoralis from the polluted site embryos differing form each other by one developmental stage were identified. Egg calculation revealed a K- reproductive strategy of X. nemoralis from polluted sites. Finally, future prospects and benefits, and weaknessess of this method for the study of spider cocoons have presented.     

Experiments on the implosion of heterogeneous wire arrays on the S-300 facility

Results are presented from experiments on the implosion of simple and nested wire arrays of different mass and material composition (W and/or Al). The experiments were performed on the S-300 facility (a high-current pulsed power generator with a voltage pulse amplitude of 700 kV, current amplitude of 2.5–3.5 MA, and pulse duration of 100 ns) at the Kurchatov Institute (Moscow). The imploding arrays were recorded using five-frame laser shadowgraphy, three-frame image-tube photography, an optical streak camera, X-ray pinhole cameras with different filters, X-ray polychromator, and X-ray spectrometer on the basis of a convex mica crystal. Laser probing measurements indicate that the current-carrying structure undergoes a fast (over a time shorter than 10 ns) global rearrangement, which manifests itself as the emergence of transparent regions. This effect is presumably related to the grouping of the wires, which carry currents of a few tens of kiloamperes, or to the current filamentation in their common plasma corona. The radiation of liners of different chemical composition in the final compressed state has been investigated. Electric measurements performed in experiments with nested arrays (e.g., with an aluminum outer liner and a tungsten inner liner) indicate that the inner array, which is still at rest, intercepts the electric current from the outer array when the latter penetrates through it. The effect of the “fall” of the outer liner through the inner one in the course of magnetic implosion has been revealed for the first time by analyzing X-ray emission spectra.     

The individual differences in responses of cancer patient blood cells on radiation treatment during the chemotherapy

A comparative comet-assay study of X-ray influence on DNA of leukocytes of peripheral blood from both cancer patients in the course of chemotherapy and on healthy donors was carried out. The amount of DNA registered in comet tails of blood samples from 18 healthy donors was between 0.8-3.6%. The mean value was 2.9 +/- 0.5%. In the preparations of cancer patients, an increase in comet tail DNA was observed for each chemotherapy course and in each subsequent course compared to the previous one. The individual variations were found in the level of DNA damage in the response to the administration of cyclophosphane, of methotrexate, of 5-fluorourocil (CMF protocol). The X-ray radiation (4 Gy) challenge test of blood cells showed an increase in comet tail DNA, the dynamics of radiation-induced lesions varying between individuals. The combined use of X-ray radiation and of the comet-assay in evaluating the capacity of the defence systems of the whole blood cells during chemotherapy let us to hold the monitoring of the state of genome of leukocytes without their isolation. This approach enables additional information on leukocyte genome to be rapidly obtained.     

Imaging plate and its application to X-ray diffraction of muscle

The excellent performance of the IP as an integrating X-ray area detector makes it well suited to X-ray diffraction and scattering experiments using synchrotron radiation. The IP is particularly useful for biological specimens for which the shortest exposure time or the smallest amount of X-ray dose possible is required. It is also useful for time-resolved measurements of an X-ray diffraction pattern, to complement its uses in static measurements.A combination of two powerful tools, synchrotron radiation and imaging plates, has mutually enhanced the potentials of both. The IP may replace conventional X-ray film and some other X-ray detectors which have been conventionally used in many of the application fields of synchrotron radiation. As examples, it has recently proved to be very promising in experiments of X-ray diffraction under high pressure and high temperature (12) DEXAFS and X-ray diffuse scattering. X-ray microscopy will also benefit from the IP when the spatial resolution is improved to a few tens of microns in FWHM.When more intense X-rays are available from insertion devices installed in planned 6–8 GeV storage rings, the IP system will play a more important role as one of the best X-ray area detectors because of its high DQE and the lack of any instantaneous count-rate limitations.     

A review of sources of spurious silicon peaks in electron microprobe X-ray spectra of biological specimens.

The presence of Si peaks in X-ray spectra of biological specimens can lead to misinter-pretation of data if one is unaware of potential sourees of artifactual Si. Silicontcontamination may be acquired from oils or greases during the course of specimen preparation or from the vacuum system of the electron microscope. In energy dispersive X-ray detection, the level of the Si peak cannot be reduced below that of the internal fluorescence peak obtained from the dead layer of the detector.     

FR207944, an antifungal antibiotic from Chaetomium sp. No. 217 II. Isolation and structure elucidation

We discovered FR207944 produced by Chaetomium sp. No. 217 in the course of screening for antifungal antibiotics from natural products. FR207944 is identical with fuscoatroside, described in the preceding paper as an anti-Aspergillus flavus agent. Determination of the relative stereochemistry of fuscoatroside was made formally by comparison with WF11605 (16-Oxo-FR207944). We confirmed the stereochemistry on the basis of single crystal X-ray analysis.     

Physical evaluation of a new technique for X-ray dose reduction: Measurement of signal-to-noise ratio and modulation transfer function in an animal model

Aim of this study was to record objective changes in image quality of optically re-exposed, radiation-reduced X-ray images in comparison to a normally exposed reference image in an animal model.Under investigation is the question if optical re-exposure of conventional, radiation-reduced X-ray images partially or even fully compensates the loss of information caused by underexposure.Dose-reduced, underexposed images were prepared by reducing the mAs product to 50% with constant anode voltage. Reproduction of the image was performed with a 52% decrease in the radiation dose. Comparing different re-exposure times, the optimal time was found to be 60 s. These underexposed X-rays were then optically re-exposed for a defined period of time before development. In all X-ray images of the animal model, different osseous structures were defined as regions of interest (ROI) for evaluation of the objective changes in image quality. The density curves were plotted with the two-beamed densitometer. The contrast transfer factors as the function of local frequency were determined from this, which served as the basis for calculating the modulation transfer factor. To establish if X-ray sensitisation by optical re-exposure leads to a change in the sensitometric gradation, the sensitometric curves were determined using a standardized aluminum scale and thermal luminescence dosimetry.In the comparison the lowest correlation with the standard technique film (X-ray 1) was seen in the purely dose-reduced X-ray. In the range of 1.6–3.4 Lp/mm, both SNR curves have an identical course. Despite a 52% dose reduction in the re-exposed image, both densitometry curves of the conventional and re-exposed X-ray show an almost identical distribution of the transmittance levels. In conclusion film sensitisation provides a technically simple and inexpensive procedure, which is easily integrated into previous film development processes and considerably reduces the patient radiation exposure as well as clearly improving the image quality.     

Development of a G2/M arrest high-throughput screening method identifies potent radiosensitizers

Radiation is a powerful tool used to control tumor growth and induce an immune response; however, it is limited by damage to surrounding tissue and adverse effects such skin irritation. Breast cancer patients in particular may endure radiation dermatitis, and potentially lymphedema, after a course of radiotherapy. Radio-sensitizing small molecule drugs may enable lower effective doses of both radiation and chemotherapy to minimize toxicity to healthy tissue. In this study, we identified a novel high-throughput method for screening radiosensitizers by image analysis of nuclear size and cell cycle. In vitro assays were performed on cancer cells lines to assess combined therapeutic and radiation effects. In vivo, radiation in combination with proflavine hemisulfate led to enhanced efficacy demonstrated by improved tumor volume control in mice bearing syngeneic breast tumors. This study provides a proof of concept for utilizing G2/M stall as a predictor of radiosensitization and is the first report of a flavin acting as an X-ray radiation enhancer in a breast cancer mouse model.     

High-resolution structure of the photosynthetic Mn4Ca catalyst from X-ray spectroscopy

The application of high-resolution X-ray spectroscopy methods to study the photosynthetic water oxidizing complex, which contains a unique hetero-nuclear catalytic Mn4Ca cluster, is described. Issues of X-ray damage, especially at the metal sites in the Mn4Ca cluster, are discussed. The structure of the Mn4Ca catalyst at high resolution, which has so far eluded attempts of determination by X-ray diffraction, X-ray absorption fine structure (EXAFS) and other spectroscopic techniques, has been addressed using polarized EXAFS techniques applied to oriented photosystem II (PSII) membrane preparations and PSII single crystals. A review of how the resolution of traditional EXAFS techniques can be improved, using methods such as range-extended EXAFS, is presented, and the changes that occur in the structure of the cluster as it advances through the catalytic cycle are described. X-ray absorption and emission techniques (XANES and Kbeta emission) have been used earlier to determine the oxidation states of the Mn4Ca cluster, and in this report we review the use of X-ray resonant Raman spectroscopy to understand the electronic structure of the Mn4Ca cluster as it cycles through the intermediate S-states.     

Solid state amorphization kinetic of alpha lactose upon mechanical milling

It has been previously reported that α-lactose could be totally amorphized by ball milling. In this paper we report a detailed investigation of the structural and microstructural changes by which this solid state amorphization takes place. The investigations have been performed by Powder X-ray Diffraction, Solid State Nuclear Magnetic Resonance (¹³C CP-MAS) and Differential Scanning Calorimetry. The results reveal the structural complexity of the material in the course of its amorphization so that it cannot be considered as a simple mixture made of a decreasing crystalline fraction and an increasing amorphous fraction. Heating this complexity can give rise to a fully nano-crystalline material. The results also show that chemical degradations upon heating are strongly connected to the melting process.