Cryo-soft X-ray tomography is an imaging technique that addresses the need for mesoscale imaging of cellular ultrastructure of relatively thick samples without the need for staining or chemical modification. It allows the imaging of cellular ultrastructure to a resolution of 25–40 nm and can be used in correlation with other imaging modalities, such as electron tomography and fluorescence microscopy, to further enhance the information content derived from biological samples. An overview of the technique, discussion of sample suitability and information about sample preparation, data collection and data analysis is presented here. Recent developments and future outlook are also discussed.
The ESRF synchrotron beamline ID22, dedicated to hard X-ray microanalysis and consisting of the combination of X-ray fluorescence, X-ray absorption spectroscopy, diffraction and 2D/3D X-ray imaging techniques, is one of the most versatile instruments in hard X-ray microscopy science. This paper describes the present beamline characteristics, recent technical developments, as well as a few scientific examples from recent years of the beamline operation. The upgrade plans to adapt the beamline to the growing needs of the user community are briefly discussed.
Hard X-ray fluorescence microscopy and magnified phase contrast imaging are combined to obtain quantitative maps of the projected metal concentration in whole cells. The experiments were performed on freeze dried cells at the nano-imaging station ID22NI of the European Synchrotron Radiation Facility (ESRF). X-ray fluorescence analysis gives the areal mass of most major, minor and trace elements; it is validated using a biological standard of known composition. Quantitative phase contrast imaging provides maps of the projected mass and is validated using calibration samples and through comparison with Atomic Force Microscopy and Scanning Transmission Ion Microscopy. Up to now, absolute quantification at the sub-cellular level was impossible using X-ray fluorescence microscopy but can be reached with the use of the proposed approach.
Hard X-ray fluorescence microscopy and magnified phase contrast imaging are combined to study radiation effects on cells. Experiments were performed on freeze-dried cells at the nano-imaging station ID22NI of the European synchrotron radiation facility. Quantitative phase contrast imaging provides maps of the projected mass and is used to evaluate the structural changes due to irradiation during X-ray fluorescence experiments. Complementary to phase contrast imaging, scanning transmission ion microscopy is performed and doses of all the experiments are compared. We demonstrate the sensitivity of the proposed approach to study radiation-induced damage at the sub-cellular level.
Introduction
Erysipelas and bacterial cellulitis are two of the most common infectious skin diseases. They are usually caused by the β-hemolytic group of
Streptococcus
, and less frequently by other bacteria. The objective of the study was to assess the factors affecting the length of stay of patients admitted to hospital with erysipelas or bacterial cellulitis.
Methods
The study was based on the retrospective analysis of medical records of patients diagnosed with erysipelas or bacterial cellulitis. Selected clinical features of the disease, the results of additional tests, the treatment used, and the time of hospitalization were analyzed. Among an initial group of 78 pre-identified patients, 59 subjects aged from 32 to 89 years were included in the final analysis. The time spent in the hospital and the number of antibiotics necessary to cure the patient were chosen as the parameters of treatment efficacy.
Results
The average duration of stay in a hospital was 7.0 ± 2.9 days and was slightly longer for women than for men. Patients with chills on admission, with coexisting chronic venous insufficiency of the lower limbs, and with anemia were hospitalized for a significantly longer period than those without these conditions. A combination therapeutic regimen of amoxicillin + clavulanic acid was the most commonly used treatment option, and this therapy was linked with shortest duration of stay in the hospital; the length of hospital stay was significantly longer for those patients receiving cephalosporins or clindamycin as treatment. The combination therapy of amoxicillin + clavulanic acid as treatment option was also least often associated with the need to use other antibacterial agents.
Conclusions
Based on our evaluation of 59 subjects with either erysipelas or bacterial cellulitis, combination therapy with amoxicillin + clavulanic acid appears to be linked with the shortest stay in the hospital. We suggest that this combination therapy should be considered as a first-line treatment for patients hospitalized due to erysipelas or bacterial cellulitis, if other factors did not preclude the use of this therapy.
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