In vivo X-ray cine-tomography for tracking morphological dynamics

Scientific cinematography using ultrafast optical imaging is a common tool to study motion. In opaque organisms or structures, X-ray radiography captures sequences of 2D projections to visualize morphological dynamics, but for many applications full four-dimensional (4D) spatiotemporal information is highly desirable. We introduce in vivo X-ray cine-tomography as a 4D imaging technique developed to study real-time dynamics in small living organisms with micrometer spatial resolution and subsecond time resolution. The method enables insights into the physiology of small animals by tracking the 4D morphological dynamics of minute anatomical features as demonstrated in this work by the analysis of fast-moving screw-and-nut–type weevil hip joints. The presented method can be applied to a broad range of biological specimens and biotechnological processes.The best method to study morphological changes of anatomic features and physiological processes is to observe their dynamics in 4D, that is, in real time and in 3D space. To achieve this we have developed in vivo X-ray cine-tomography to gain access to morphological dynamics with unrivaled 4D spatiotemporal resolution. This opens the way to a wide range of hitherto inaccessible, systematic investigations of small animals and biological internal processes such as breathing, circulation, digestion (1), reproduction, and locomotion (2).At the micrometer resolution range, state-of-the-art optical imaging techniques can achieve high magnifications to visualize tissues and even individual cells for 4D studies. These methods however are confined to transparent or fluorescent objects, or are limited either by low penetration depth <1 mm or poor time resolution (3). For optically opaque living organisms X-ray imaging methods are highly appropriate due to the penetrating ability of the radiation. Modern synchrotron radiation facilities provide brilliant and partially coherent radiation suitable for high-resolution volume imaging methods such as X-ray computed microtomography (SR-µCT). For static specimens SR-µCT has proven to be a powerful tool to study small animal morphology in 3D (4–6). The benefits of various physical contrast mechanisms, high spatial resolution, and short measuring times, as well as enormous sample throughput compared with laboratory X-ray setups, have led to its widespread use in life sciences.Real-time in vivo X-ray imaging with micrometer spatial resolution was realized so far by recording time sequences of 2D projection radiographs of different organisms (1, 6, 7), providing time information about functional dynamics but losing any information about the third spatial dimension.Recently, 4D in vivo X-ray experiments have been performed to study cell migration in frog embryos (8, 9) using tomographic sequences of a few seconds exposure time per tomogram interrupted by longer nonexposure time slots. In this way the authors followed relatively slow dynamics and morphological changes during embryonic development with 2-µm resolution over total time intervals of several hours. The fastest 4D time series yet reported were realized with a temporal resolution of 0.5 s and spatial resolution of 25 µm (10), applied to a living caterpillar used as test specimen for imaging, but without any analysis of dynamics.In this paper, we demonstrate the quantitative 4D investigation of morphological dynamics by in vivo X-ray 4D cine-tomography, introduced here as the combination of ultrafast SR-µCT and motion analysis procedures. Using this approach allows us to investigate previously inaccessible 3D morphological dynamics in small animals, presently with feature sizes in the micrometer range and with temporal resolution down to a few tens of milliseconds. In the past, ultrafast in vivo imaging was hardly possible for such applications, due to the strongly competing requirements for simultaneous high contrast, high signal-to-noise ratio (SNR), and concurrent low radiation dose, as well as the need for simultaneous high spatial resolution and maximum temporal resolution.In the following we describe how in vivo X-ray 4D cine-tomography meets the above challenges by optimizing image contrast, SNR, and spatial and temporal resolution in the ultrafast SR-µCT system and by establishing a dedicated data analysis pipeline, all within a unified framework (Fig. S1). We demonstrate the potential of the technique by investigating morphological dynamics in fast-moving weevils, focusing here on the exoskeletal joints.     

Working with the history of life: a researcher mishaps?

In this study, characterized as a qualitative one, whose author tells about her experience when accomplishing her Doctorate thesis for the History of life method. She describes the methodological approach, turning explicit the collection and the report analysis technique as well as the incidental difficulties that may turn up during the research completion. She concludes that this method turns the approach among the researcher and the individuals feasible. It points out the need to include the subjective dimension of the care in the assistance rendered to the clientele.     

Anestesia e doença de Alzheimer – Percepções atuais

Background and objectives

It has been speculated that the use of anesthetic agents may be a risk factor for the development of Alzheimer disease. The objective of this review is to describe and discuss pre‐clinical and clinical data related to anesthesia and this disease.

Parathyroidectomy in patients with chronic kidney disease: Impacts of different techniques on the biochemical and clinical evolution of secondary hyperparathyroidism

Background

Parathyroidectomy (PTx) decreases the mortality rate of refractory secondary hyperparathyroidism (rSHP) due to chronic kidney disease. A consensus regarding which techniques of PTx are associated with better outcomes is not available. The aims of this study are to evaluate the clinical and laboratory evolution of 49 hemodialysis patients with rSHP who underwent PTx using different techniques.

Cyclosporine Versus Tacrolimus: Which Calcineurin Inhibitor Has Influence on Cytomegalovirus Infection in Cardiac Transplantation?

Introduction

Cytomegalovirus (CMV) infection is a relevant cause of morbidity and mortality in transplantation patients. Its major incidence is in the first year and viral replication is related to acute rejection, survival reduction, and graft vascular disease.

Functional Results of Renal Preservation in Hypothermic Pulsatile Machine Perfusion Versus Cold Preservation: Systematic Review and Meta-Analysis of Clinical Trials

Background

Hypothermic pulsatile machine perfusion (HPMP) decreases the rate of delayed graft function (DGF) in kidney grafts, compared with cold storage. However, it is not clear its use in the different subgroups of grafts. The objective was to review systematically all studies with better methodologic quality that compare HPMP versus cold storage.

Long-term Prognosis After Lung Transplantation: A Monocentric Study in 510 Patients

Introduction

Lung transplantation is the final treatment option in patients with respiratory failure. Morbidity and mortality rates associated with the management of complications is high despite advances. Postoperative complications include acute transplant rejection, bronchiolitis obliterans, and infections. Because of that, the success of this treatment option depends on the correct choice of donor and candidates to receive a transplant.

Photobiomodulation increases mitochondrial citrate synthase activity in rats submitted to aerobic training

This study investigated the effects of photobiomodulation by low-laser laser therapy (LLLT) on the activities of citrate synthase (CS) and lactate dehydrogenase (LDH) and the anaerobic threshold (AT) in rats submitted to treadmill exercise. Fifty-four rats were allocated into four groups: rest control (RCG), rest laser (RLG), exercise control (ECG), and exercise laser (ELG). The infrared LLLT was applied daily on the quadriceps, gluteus maximum, soleus, and tibialis anterior muscles. Muscle samples (soleus, tibialis anterior, and cardiac muscles) were removed 48 h after the last exercise session for spectrophotometric analysis of the CS and LDH. The CS activity (μmol/protein) in ELG (16.02 and 0.49) was significantly greater (P?<?0.05) than RCG (2.34 and 0.24), RLG (6.25 and 0.17), and ECG (6.76 and 0.26) in the cardiac and soleus muscles, respectively. The LDH activity (in 1 Mm/protein) in soleus muscle was smaller (P?<?0.05) for ELG (0.33) compared to ECG (0.97), RLG (0.79), and RCG (1.07). For cardiac muscle, the LDH activity was smaller (P?<?0.05) in ELG (1.38) compared to ECG (1.91) and RCG (2.55). The ECG and ELG showed increases in the maximum speed and a shift of the AT to higher effort levels after the training period, but no differences occurred between the exercised groups. In conclusion, the aerobic treadmill training combined with LLLT promotes an increase of oxidative capacity in this rat model, mainly in muscles with greater aerobic capacity.     

Bactericide effect of methylene blue associated with low-level laser therapy in <Emphasis Type="Italic">Escherichia coli</Emphasis> bacteria isolated from pressure ulcers

The present study analyzed the bactericidal effect of methylene blue associated with low-level lasers on Escherichia coli isolated from a pressure ulcer. Microbiological material from a pressure ulcer was isolated using an aseptic swab, and antimicrobial activity was verified using the diffusion disc method. Methylene blue was used at concentrations of 0.001 and 0.005%, and low-level lasers of 670, 830, and 904 nm, with the energy densities of 4, 8, 10, and 14 J/cm², were tested on three plates each and combined with methylene blue of each concentration. In addition, three control plates were used, with each concentration and energy density separated without any interventions. The results were analyzed using the paired sample t test to determine the bactericidal effect of the methylene blue and using the ANOVA test to compare the effects of the energy densities and wavelengths among the low-level laser treatment protocols. The results showed bacterial reduction at wavelengths of 830 and 904 nm and more proliferation in wavelengths of 670 nm. In wavelength of 830 nm, a bacterial reduction was observed in the conditions with 0.001% methylene blue in all energy density utilized, with 0.005% methylene blue in energy density of 10 J/cm², and without methylene blue in energy density at 10 J/cm². And in a wavelength of 904 nm, all condition showed bacterial reduction with or without methylene blue. We concluded that the low-level lasers of 904 and 830 nm have bactericidal effects and at better energy densities (10 and 14 J/cm²).