Liver Function Changes After Technetium-99m-Macroaggregated Albumin Administration and Their Predictive Value Regarding Hepatotoxicity in Patients Undergoing Yttrium-90-Radioembolization

BACKGROUND/AIM

Intraarterial Technetium-99m-Macroaggregated Albumin (^99mTc-MAA) administration is an established method to predict particle distribution prior to radioembolization. This study aimed to analyse the impact of intraarterial administration of ^99mTc-MAA on changes in liver-specific laboratory parameters and to assess whether such changes are associated with post-radioembolization hepatotoxicity.

PATIENTS AND METHODS

A total of 202 patients treated with radioembolization received prior mapping angiography with ^99mTc-MAA administration. All patients underwent clinical and laboratory examinations, including liver-specific parameters at certain times before and after mapping angiography/^99mTc-MAA administration, as well as before radioembolization and during follow-up.

RESULTS

Bilirubin increased temporarily after ^99mTc-MAA administration (p<0.001), but was not clinically relevant, and returned close to the initial value before radioembolization. These changes showed no association with subsequent postradioembolic hepatotoxicity or shortened overall survival.

CONCLUSION

^99mTc-MAA administration results in a significant, however, not clinically relevant transient increase in bilirubin levels, which does not provide a predictive value for subsequent radioembolization outcome or postradioembolic hepatotoxicity.

Free propagation phase-contrast breast CT provides higher image quality than cone-beam breast-CT at low radiation doses: a feasibility study on human mastectomies

In this study we demonstrate the first direct comparison between synchrotron x-ray propagation-based CT (PB-CT) and cone-beam breast-CT (CB-CT) on human mastectomy specimens (N = 12) including different benign and malignant lesions. The image quality and diagnostic power of the obtained data sets were compared and judged by two independent expert radiologists. Two cases are presented in detail in this paper including a comparison with the corresponding histological evaluation. Results indicate that with PB-CT it is possible to increase the level of contrast-to-noise ratio (CNR) keeping the same level of dose used for the CB-CT or achieve the same level of CNR reached by CB-CT at a lower level of dose. In other words, PB-CT can achieve a higher diagnostic potential compared to the commercial breast-CT system while also delivering a considerably lower mean glandular dose. Therefore, we believe that PB-CT technique, if translated to a clinical setting, could have a significant impact in improving breast cancer diagnosis.

X-ray-Based 3D Virtual Histology-Adding the Next Dimension to Histological Analysis

Histology and immunohistochemistry of thin tissue sections have been the standard diagnostic procedure in many diseases for decades. This method is highly specific for particular tissue regions or cells, but mechanical sectioning of the specimens is required, which destroys the sample in the process and can lead to non-uniform tissue deformations. In addition, regions of interest cannot be located beforehand and the analysis is intrinsically two-dimensional. Micro X-ray computed tomography (μCT) on the other hand can provide 3D images at high resolution and allows for quantification of tissue structures, as well as the localization of small regions of interest. These advantages advocate the use of μCT for virtual histology tool with or without subsequent classical histology. This review summarizes the most recent examples of virtual histology and provides currently known possibilities of improving contrast and resolution of μCT. Following a background in μCT imaging, ex vivo staining procedures for contrast enhancement are presented as well as label-free virtual histology approaches and the technologies, which could rapidly advance it, such as phase-contrast CT. Novel approaches such as zoom tomography and nanoparticulate contrast agents will also be considered. The current evidence suggests that virtual histology may present a valuable addition to the workflow of histological analysis, potentially reducing the workload in pathology, refining tissue classification, and supporting the detection of small malignancies.

Effects of repetitive prolonged breath-hold in elite divers on myocardial fibrosis and cerebral morphology

BACKGROUND

Prolonged apnea by breath-hold (BH) divers leads to hypoxemia and compensatory mechanisms of the cardiovascular system (i.e. increase of total peripheral resistance, increase of systolic blood-pressure, left-ventricular enlargement) to maintain oxygen supply to oxygen sensitive organs such as the brain. All these changes may result in structural myocardial or subclinical brain alterations. Therefore, the aim of this study was to investigate mid-term effects of repetitive prolonged apnea using cardiac magnetic resonance imaging (CMR) and magnetic resonance imaging of the brain.

MATERIALS AND METHODS

17 elite BH divers (15 males) were investigated at baseline, from whom 9 (7 males) were investigated again at follow-up one year later. CMR included functional imaging and tissue characterization using T1- and T2-mapping as well as late gadolinium enhancement. Results were compared intra-individually and with 50 age matched controls.

RESULTS

Mean BH time were 297 ± 52 s (entire cohort) and 315 ± 56 s (sub-cohort) at initial, and 334 ± 104 s at follow-up examination. Apnea resulted in a progressive increase of the left ventricle and impaired function, whichfully resolved after cessation of apnea. At rest, no dilation of the left ventricle was notable (LV-EDV: 106.7 ± 28.8 ml; LV-EDV/BSA: 52.2 ± 12.7 ml/m²). Compared to controls, the apnea group showed significantly lower volumes (LV-EDV: 106.7 ± 28.8 ml vs. 140.9 ± 36.3 ml, p = .008; LV-EDV/BSA: 52.2 ± 12.7 ml/m² vs. 73.7 ± 12.8 ml/m²). In contrast, LV-EF showed no significant differences between both groups (61.0 ± 7.0% vs. 60.9 ± 3.6%). T1- and T2-mapping revealed no significant differences, neither intra-individually nor in comparison with age matched controls. (T1 pre-contrast: 974.1 ± 12.9 ms vs. 969.4 ± 29.0 ms, p = .2; T1 post-contrast: 368.9 ± 38.5 ms vs. 966.7 ± 40.5 ms, p = .4; ECV: 29.2 ± 1.5% vs. 29.8 ± 1.6%, p = .3; T2. 52 ± 2 ms vs. 52 ± 3 ms; p = .4). Except for one old embolic lesion no structural changes were found in brain imaging.

CONCLUSION

Although, prolonged apnea leads to impressive adaptions of the cardiovascular system (i.e. dilation of the left ventricle) and hypertension due to peripheral vasoconstriction no mid-term morphological changes could be observed in both, the myocardium and the brain. BH divers are suitable as a model to investigate acute physiological changes of prolonged apnea and hypoxemia, but not as a model for chronic alterations.

Influence of Donor Age and Stimulation Intensity on Osteogenic Differentiation of Rat Mesenchymal Stromal Cells in Response to Focused Low-Intensity Pulsed Ultrasound

A focused low-intensity pulsed ultrasound (FLIPUS) was used to investigate the effects of stimulation period, acoustic intensity and donor age on the osteogenic differentiation potential of rat mesenchymal stromal cells (rMSCs). rMSCs from 3- and 12-mo-old female Sprague Drawly rats were isolated from bone marrow and stimulated 20 min/d with either 11.7 or 44.5 mW/cm² (spatial average temporal average intensity) for 7 or 14 d. Osteogenic differentiation markers, i.e., Runt-related transcription factor 2 (RUNX2), osteocalcin (OCN) and degree of matrix calcification were analyzed. On day 7 of stimulation, OCN gene expression was enhanced 1.9-fold in cells from young rats when stimulated with low intensity. The low intensity also led to a 40% decrease in RUNX2 expression on day 7 in aged cells, whereas high intensity enhanced expression of RUNX2 on day 14. FLIPUS treatment with low intensity resulted in a 15% increase in extracellular matrix mineralization in young but not old rMSCs. These differences suggest the necessity of a donor-age related optimization of stimulation parameters.

Reconstitution of Fusion Proteins in Supported Lipid Bilayers for the Study of Cell Surface Receptor-Ligand Interactions in Cell-Cell Contact

Bioactive molecules such as adhesion ligands, growth factors, or enzymes play an important role in modulating cell behavior such as cell adhesion, spreading, and differentiation. Deciphering the mechanism of ligand-mediated cell adhesion and associated signaling is of great interest not only for fundamental biophysical investigations but also for applications in medicine and biotechnology. In the presented work, we developed a new biomimetic platform that enables culturing primary neurons and testing cell surface-receptor ligand interactions in cell-cell contacts as, e.g., in neuronal synapses. This platform consists of a supported lipid bilayer modified with incorporated neuronal adhesion proteins conjugated with the Fc-domain of IgG (ephrin A5 Fc-chimera). We extensively characterized properties of these protein containing bilayers using fluorescence recovery after photobleaching (FRAP), quartz crystal microbalance with dissipation (QCM-D), and immunostaining. We conclude that the Fc-domain is the part responsible for the incorporation of the protein into the bilayer. The biomimetic platform prepared by this new approach was able to promote neuronal cell adhesion and maintain growth as well as facilitate neuronal maturation as shown by electrophysiological measurements. We believe that our approach can be extended to insert other proteins to create a general culture platform for neurons and other cell types.

Identification of molecular markers for articular cartilage

OBJECTIVE

The aim of the current study was to identify molecular markers for articular cartilage (AC) that can be used as tools for the quality control of tissue engineered (TE) cartilage.

DESIGN

A genome-wide expression analysis was performed using RNA isolated from articular and growth plate (GP) cartilage, both extracted from the knee joints of 6 weeks old minipigs. After confirming the specific expression for selected genes by RT-PCR, these were used as molecular markers for the quality control of TE cartilage.

RESULTS

Albeit several known chondrocyte markers were expressed to a similar extent in articular and GP cartilage, our genome-wide expression analysis led us to identify genes being selectively expressed in either GP or articular chondrocytes. These findings led us to perform a RT-PCR expression analysis for the corresponding genes to demonstrate the absence of GP-specific markers in TE cartilage, while common or AC markers were expressed.

CONCLUSIONS

Taken together, these results provide important novel insights into chondrocyte biology in general and AC in particular. In addition, it is reasonable to speculate, that some of the identified genes play distinct roles in the regulation of articular chondrocyte differentiation and/or function, thereby raising the possibility that they may serve as targets for non-operative therapies of osteoarthritis (OA).