Temperature Sensing Properties of Biocompatible Yb/Er-Doped GdF3 and YF3 Mesocrystals.

Y0.8-xGdxF3:Yb/Er mesocrystals with a biocompatible surface and diverse morphological characteristics were successfully synthesized using chitosan-assisted solvothermal processing. Their structural properties, studied using X-ray powder diffraction, Fourier transform infrared spectroscopy, scanning and transmission electron microscopy and energy dispersive X-ray analysis, were further correlated with the up-conversion emission (λexc = 976 nm) recorded in function of temperature. Based on the change in the visible green emissions originating from the thermally coupled 2H11/2 and 4S3/2 levels of Er3+, the corresponding LIR was acquired in the physiologically relevant range of temperatures (25-50 °C). The detected absolute sensitivity of about 0.0042 °C-1, along with the low cytotoxicity toward both normal human lung fibroblasts (MRC-5) and cancerous lung epithelial (A549) cells, indicate a potential for use in temperature sensing in biomedicine. Additionally, their enhanced internalization in cells, without suppression of cell viability, enabled in vitro labeling of cancer and healthy cells upon 976 nm laser irradiation.

Synthesis and Biological Properties of Alanine-Grafted Hydroxyapatite Nanoparticles.

Hydroxyapatite attracts great attention as hard tissues implant material for bones and teeth. Its application in reconstructive medicine depends on its biocompatibility, which is in a function of composition and surface properties. The insertion of a protein element in the composition of implants can improve the cell adhesion and the osseointegration. Having this in mind, the proposal of this work was to develop L-alanine-grafted hydroxyapatite nanoparticles and to study their biocompatibility. Two L-alanine sources and three grafting methods were used for hydroxyapatite surface functionalization. The efficiency of grafting was determined based on X-ray powder diffraction, Fourier-transform infrared spectroscopy, thermal analyses, and field-emission scanning electron microscopy. The results indicated the formation of hydroxyapatite with 8-25 wt% of organic content, depending on the grafting method. Protein adsorption, cell adhesion, and viability studies were carried out to evaluate biological properties of grafted materials. The viability of MG-63 human osteoblastic cells following 24 h incubation with the alanine-grafted hydroxyapatite samples is well preserved, being in all cases above the viability of cells incubated with hydroxyapatite. The alanine-grafted hydroxyapatite prepared in situ and by simple mixture showed higher protein adsorption and cell adhesion, respectively, indicating their potential toward use in regenerative medicine.

Up-converting nanoparticles synthesis using hydroxyl-carboxyl chelating agents: Fluoride source effect.

The synthesis of lanthanide doped up-converting nanoparticles (UCNPs), whose morphological, structural, and luminescence properties are well suited for applications in optoelectronics, forensics, security, or biomedicine, is of tremendous significance. The most commonly used synthesis method comprises decomposition of organometallic compounds in an oxygen-free environment and subsequent infliction of a biocompatible layer on the particle surface. In this work, hydroxyl-carboxyl (-OH/-COOH) type of chelating agents (citric acid and sodium citrate) are used in situ for the solvothermal synthesis of hydrophilic NaY0.5Gd0.3F4:Yb,Er UCNPs from rare earth nitrate salts and different fluoride sources (NaF, NH4F, and NH4HF2). X-ray powder diffraction showed crystallization of cubic and hexagonal NaY0.5Gd0.3F4:Yb,Er phases in nano- and micro-sized particles, respectively. The content of the hexagonal phase prevails in the samples obtained when Na-citrate is used, while the size and shape of the synthesized mesocrystals are affected by the choice of fluoride source used for precipitation. All particles are functionalized with citrate ligands and emit intense green light at 519 nm and 539 nm (2H11/2, 4S3/2 → 4I15/2) under near infrared light. The intensity of this emission is distressed by the change in the origin of phonon energy of the host matrix revealed by the change in the number of the excitation photons absorbed per emitted photon.

EFFECT OF PREOPERATIVE RESPIRATORY REHABILITATION IN PATIENTS UNDERGOING CARDIAC SURGERY.

The aim of the study was to evaluate the effects of preoperative respiratory rehabilitation on functional capacity, length of stay in intensive care unit (ICU), duration of mechanical ventilation (MV) and total hospitalization, as well as to estimate arterial blood gas (ABG) values in patients undergoing cardiac surgery. Nineteen patients were included in the randomized observational study, divided into two groups: group A (intervention) and B (control). Preoperative and postoperative rehabilitation was performed in group A, and only postoperative rehabilitation in group B. Rehabilitation was carried out according to a predefined protocol. We used ABG to evaluate respiratory function, two-minute walk test (2MWT) and sit-to-stand test to assess functional capacity. The following data were obtained from medical documentation: duration of MV, length of stay at ICU, occurrence of postoperative pulmonary complications, and length of total hospitalization in both groups. Significant between-group difference was found for the length of total hospitalization and duration of MV (p<0.05 both). Analysis of the mean values of 2MWT on the last day of hospitalization (p=0.005), sit-to-stand test before surgery (p=0.022) and on the last day of hospitalization (p=0.008) showed statistically significant differences. The length of hospital stay significantly correlated with preoperative rehabilitation in group A (r=0.885; p<0.0001). There was no difference in ABG parameters between the groups. The study showed that preoperative respiratory rehabilitation had an effect on reducing duration of MV and length of total hospitalization, and improved functional capacity.

Rare-earth (Gd3+,Yb3+/Tm3+, Eu3+) co-doped hydroxyapatite as magnetic, up-conversion and down-conversion materials for multimodal imaging.

Taking advantage of the flexibility of the apatite structure, nano- and micro-particles of hydroxyapatite (HAp) were doped with different combinations of rare earth ions (RE3+ = Gd, Eu, Yb, Tm) to achieve a synergy among their magnetic and optical properties and to enable their application in preventive medicine, particularly diagnostics based on multimodal imaging. All powders were synthesized through hydrothermal processing at T ≤ 200 °C. An X-ray powder diffraction analysis showed that all powders crystallized in P63/m space group of the hexagonal crystal structure. The refined unit-cell parameters reflected a decrease in the unit cell volume as a result of the partial substitution of Ca2+ with smaller RE3+ ions at both cation positions. The FTIR analysis additionally suggested that a synergy may exist solely in the triply doped system, where the lattice symmetry and vibration modes become more coherent than in the singly or doubly doped systems. HAp:RE3+ optical characterization revealed a change in the energy band gap and the appearance of a weak blue luminescence (λex = 370 nm) due to an increased concentration of defects. The "up"- and the "down"-conversion spectra of HAp:Gd/Yb/Tm and HAp:Gd/Eu powders showed characteristic transitions of Tm3+ and Eu3+, respectively. Furthermore, in contrast to diamagnetic HAp, all HAp:RE3+ powders exhibited paramagnetic behavior. Cell viability tests of HAp:Gd/Yb/Tm and HAp:Gd/Eu powders in human dental pulp stem cell cultures indicated their good biocompatibility.

Immunohistochemical study of cyclin A and p16 expression in patients with renal cell carcinoma.

PURPOSE: Renal cell carcinoma (RCC) is the most common malignant kidney tumor in adults. Dysregulation of the cell cycle can lead to cancer development. In this study, the mitosis-associated cyclin A and p16, a negative controller, were investigated as potential key points in the RCC development. METHODS: This retrospective study included 74 patients with RCC. The expression of cyclin A and p16 and their correlation to histopathological parameters (TNM stage, histological subtype, nuclear grade, tumor size), gender, age, and clinical outcome were studied and analyzed. RESULTS: The highest median value for cyclin A (40%; range 0-70)) and for p16 (57.5%); range 35-80) were found in the papillary histological subtype. Survival analysis showed that in the group of patients that had died before September 2015, the median value for cyclin A was 20% (range 0-60), which was significantly higher than 5% (range 0-70), found in the group of patients that survived (p=0.019). CONCLUSIONS: In relation to the histological subtype, the papillary type of RCC was associated with a significantly higher expression of cyclin A and p16 compared to other subtypes of RCC. High expression of cyclin A indicated worse prognosis, therefore cyclin A could be considered to be a significant prognostic marker.

Diabetic Polyneuropathy and Risk of Falls: Fear of Falling and Other Factors.

The aim of the study was to analyze postural stability, walking speed and fear of falling in patients with diabetic polyneuropathy (DPN) in order to determine the risk factors for falls, as well as the effect of DPN characteristics as additional factors. A sample of 48 patients with type 2 diabetes and DPN were enrolled in this non-randomized observational study. The patients were divided into two groups of fallers and non-fallers. All subjects underwent evaluation with the Functional Reach Test (FRT), Tinetti Falls Efficacy Scale (Tinetti FES) and 10-Meter Walk Test (10MWT). Neuropathy was quantified with the Michigan Neuropathy Screening Instrument (MNSI, Questionnaire part) and 5.07/10-g Semmes Weinstein monofilament examination (SW-ME). The 10MWT and SW-ME were significantly different between the faller and non-faller groups (p<0.05). Duration of DPN correlated positively with SW-ME (p=0.005) in the faller group. FES showed significant positive correlation with MNSI and negative correlation with 10MWT in the non-faller group. Logistic regression analysis revealed that SW-ME was significantly associated with the probability of falling (p=0.0076; OR=1.378). Study results suggested that the loss of protective sensitivity of foot could be a risk factor for falls in people suffering from type 2 diabetes.