Silicon is known to have an influence on calcium phosphate deposition and on the differentiation of bone precursor cells. This study explores the effect of the incorporation of silanol (Si–OH) groups ...into polymeric scaffolds on the osteogenic differentiation of human adipose stem cells (hASC) cultured under dynamic and static conditions. A blend of corn starch with polycaprolactone (30/70wt.%, SPCL) was used to produce three-dimensional fibre meshes scaffolds by the wet-spinning technique, and a calcium silicate solution was used as a non-solvent to develop an in situ functionalization with Si–OH groups. In vitro assessment, using hASC, of functionalized and non-functionalized scaffolds was evaluated in either α-MEM or osteogenic medium under static and dynamic conditions (provided by a flow perfusion bioreactor). The functionalized materials, SPCL–Si, exhibit the capacity to sustain cell proliferation and induce their differentiation into the osteogenic lineage. The formation of mineralization nodules was observed in cells cultured on the SPCL–Si materials. Culturing under dynamic conditions using a flow perfusion bioreactor was shown to enhance the hASC proliferation and differentiation and a better distribution of cells within the material. The present work demonstrates the potential of these functionalized materials for future applications in bone tissue engineering. Additionally, these results highlight the simplicity, economic and reliable production process of those materials.
Bioactive chitosan microparticles can be prepared successfully by treating them with a calcium silicate solution and then subsequently soaking them in simulated body fluid (SBF). Such a combination ...enables the development of bioactive microparticles that can be used for several applications in the medical field, including injectable biomaterial systems and tissue engineering carrier systems. Chitosan microparticles, 0.6
μm in average size, were soaked either for 12
h in fresh calcium silicate solution (condition I) or for 1
h in calcium silicate solution that had been aged for 24
h before use (condition II). Afterwards, they were dried in air at 60
°C for 24
h. The samples were then soaked in SBF for 1, 3 and 7 days. After the condition I calcium silicate treatment and the subsequent soaking in SBF, the microparticles formed a dense apatite layer after only 7 days of immersion, which is believed to be due to the formation of silanol (Si–OH) groups effective for apatite formation. For condition II, the microparticles successfully formed an apatite layer on their surfaces in SBF within only 1 day of immersion.
In nature, organisms control crystal nucleation and growth using organic interfaces as templates. Scientists, in the last decades, have tried to learn from nature how to design biomimetic ...biomaterials inspired by the hierarchical complex structure of bone and other natural mineralised tissues or to control the biomineralization process onto biomaterials substrates to promote the osteoconductive properties of implantable devices. The design of synthetic bone analogues, i.e., with a structure and properties similar to bone, would certainly constitute a major breakthrough in bone tissue engineering. Moreover, many strategies have been proposed in the literature to develop bioactive bone-like materials, for instance using bioactive glasses. Fundamental aspects of biomineralization may be also important in order to propose new methodologies to improve calcification onto the surface of biomaterials or to develop bioactive tridimensional templates that could be used in regenerative medicine. In particular, it has been shown that some chemical groups and proteins, as well as the tridimensional matrix in which calcification would occur, play a fundamental role on the nucleation and growth of hydroxyapatite. All these distinct aspects will be reviewed and discussed in this paper.
•Autoimmune encephalitis (AE) is an emerging, potentially reversible disease.•We presented eighteen Filipino adults and children with definite AE.•The most frequently noted manifestation is ...psychiatric disturbance.•Imaging, EEG, and CSF findings were nonspecific, but may still guide diagnosis.•Most patients improved with treatment, especially those who were treated early.
Autoimmune encephalitis (AE) is an emerging disorder in adults and children. Due to its potentially reversible nature, prompt recognition and intervention are of utmost importance.
To describe the clinical and paraclinical features, as well as treatment outcomes of patients with AE admitted in a Philippine tertiary hospital.
Retrospective case series of patients with definite AE.
Eighteen (18) patients were included (12 adults, 6 children), majority of whom had anti-N-methyl-d-aspartate receptor (NMDAR) encephalitis. The median age of onset was 32 (IQR: 10.8) years old and 13 (IQR: 4.8) years old in the adult and pediatric population, respectively. In both age groups, most presented with psychiatric symptoms and normal imaging findings. Cerebrospinal fluid (CSF) pleocytosis was detected in 8/12 (66.7%) adults and 2/6 (33.3%) children, while CSF protein elevation was only seen in 6/12 (50%) adults. Most patients presented with seizures, and the most frequent electroencephalography (EEG) abnormality detected was slow activity (70.5%). A high proportion of patients received high dose steroids, alone (35.3%) or in combination with intravenous immunoglobulin (IVIG, 52.9%). Overall, 66.7% had improved outcomes, mostly seen in the pediatric population.
This study highlighted the broad clinical phenotype, as well as the similarities and differences of AE manifestations in adults and children. It demonstrated the limited but supportive role of laboratory investigations in the diagnosis of AE. It also underscored the importance of early intervention in AE and highlighted factors influencing treatment practices and discharge outcomes in the local setting.
The aim of this work was to develop novel electrospun nanofiber meshes coated with a biomimetic calcium phosphate (BCP) layer that mimics the extracellular microenvironment found in the human bone ...structure. Poly (ε-caprolactone) (PCL) was selected because of its well-known
medical applications, its biodegradability, biocompatibility and its susceptibility to partial hydrolysis by a straightforward alkaline treatment. The deposition of a calcium phosphate layer, similar to the inorganic phase of bone, on PCL nanofiber meshes was achieved by means of a surface
modification. This initial surface modification was followed by treatment with solutions containing calcium and phosphate ions. The process was finished by a posterior immersion in a simulated body fluid (SBF) with nearly 1.5 × the inorganic concentration of the human blood plasma ions.
After some optimization work, the best conditions were chosen to perform the biological assays. The influence of the bone-like BCP layer on the viability and adhesion, as well as on the proliferation of human osteoblast-like cells, was assessed. It was shown that PCL nanofiber meshes coated
with a BCP layer support and enhance the proliferation of osteoblasts for long culture periods. The attractive properties of the coated structures produced in the present work demonstrated that those materials have potential to be used for applications in bone tissue engineering. This is the
first time that nanofiber meshes could be coated with a biomimetic bone-like calcium phosphate layer produced in a way that the original mesh architecture can be fully maintained.
Celotno besedilo
Dostopno za:
BFBNIB, DOBA, GIS, IJS, IZUM, KILJ, KISLJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
The in vitro bioactivity of a composite composed by a biodegradable starch-based polymeric matrix and hydroxyapatite fillers was investigated, in situ, as a function of immersion time in a simulated ...body fluid (SBF) using atomic force microscopy (AFM). The surface roughness of the composite started to increase after the initial 8
h because of both the degradation of the polymer matrix and the nucleation of calcium phosphate. After 24
h of immersion the surface of the composite was fully covered with calcium phosphate nuclei with diameters around 126
nm. As the immersion time increased, the nuclei increased both in number and size, and coalesced leading to the formation of a dense and uniform calcium phosphate layer on the surface of the composite only after 126
h of SBF immersion. The results of in situ AFM observation agreed with those of standard in vitro bioactivity tests in combination with scanning electron microscopy observations. Thin-film X-ray diffraction demonstrated that the ratio of apatite to the polymer matrix was higher within the surface layer (40
μm deep from the surface) than that in the bulk after the immersion for 7 days. The water-uptake capability of the polymer contributes to the nucleation and growth of the calcium phosphate layer. These results suggest the great potential of the composite for a range of temporary applications in which bone-bonding ability is a desired property.
We discuss the science motivations and prospects for a joint analysis of gravitational wave (GW) and low-energy neutrino data to search for prompt signals from nearby supernovae (SNe). Both ...gravitational wave and low-energy neutrinos are expected to be produced in the innermost region of a core-collapse supernova, and a search for coincident signals would probe the processes which power a supernova explosion. It is estimated that the current generation of neutrino and gravitational wave detectors would be sensitive to galactic core-collapse supernovae, and would also be able to detect electromagnetically dark SNe. A joint GW-neutrino search would enable improvements to searches by way of lower detection thresholds, larger distance range, better live-time coverage by a network of GW and neutrino detectors, and increased significance of candidate detections. A close collaboration between the GW and neutrino communities for such a search will thus go far toward realizing a much sought-after astrophysics goal of detecting the next nearby supernova.
O'Brien first described the actinic granuloma in 1975, as an infrequent granulomatous disorder occurring in sun-exposed skin, with a slow but often self-limited course. Ever since its initial ...description, the actinic physiopathogenic hypothesis has been debated by many authors. We report a 60-year-old female rural worker that presented with a 14 × 7 cm annular lesion with erythematous elevated borders and an atrophic center on the right calf. The lesion was evolving for 2 years, and histopathology confirmed actinic granuloma. She started acitretin with halting of disease progression after 6 months of therapy. Our case can also be associated to actinic damage, despite its unusual location, therefore highlighting the role of solar elastosis in the development of O'Brien actinic granuloma.
Recent studies suggest that thrombotic complications are a common phenomenon in the novel SARS-CoV-2 infection. The main objective of our study is to assess cumulative incidence of pulmonary embolism ...(PE) in non critically ill COVID-19 patients and to identify its predicting factors associated to the diagnosis of pulmonary embolism. We retrospectevely reviewed 452 electronic medical records of patients admitted to Internal Medicine Department of a secondary hospital in Madrid during Covid 19 pandemic outbreak. We included 91 patients who underwent a multidetector Computed Tomography pulmonary angiography(CTPA) during conventional hospitalization. The cumulative incidence of PE was assessed ant the clinical, analytical and radiological characteristics were compared between patients with and without PE. PE incidence was 6.4% (29/452 patients). Most patients with a confirmed diagnosed with PE recieved low molecular weight heparin (LMWH): 79.3% (23/29). D-dimer peak was significatly elevated in PE vs non PE patients (14,480 vs 7230 mcg/dL, p = 0.03). In multivariate analysis of patients who underwent a CTPA we found that plasma D-dimer peak was an independen predictor of PE with a best cut off point of > 5000 µg/dl (OR 3.77; IC95% (1.18–12.16), p = 0.03). We found ninefold increased risk of PE patients not suffering from dyslipidemia (OR 9.06; IC95% (1.88–43.60). Predictive value of AUC for ROC is 75.5%. We found a high incidence of PE in non critically ill hospitalized COVID 19 patients despite standard thromboprophylaxis. An increase in D-dimer levels is an independent predictor for PE, with a best cut-off point of > 5000 µg/ dl.
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