scholarly journals Cryo-Structured Materials Based on Polyvinyl Alcohol and Hydroxyapatite for Osteogenesis

2021 ◽  
Vol 12 (1) ◽  
pp. 18
Author(s):  
Daria N. Lytkina ◽  
Dmitriy A. Fedorishin ◽  
Polina M. Kalachikova ◽  
Anastasiya A. Plyaskina ◽  
Aleksandr R. Babeshin ◽  
...  
Keyword(s):  
Polyvinyl Alcohol ◽  
Calcium Phosphates ◽  
Wistar Rat ◽  
Ceramic Composites ◽  
Structured Materials ◽  
Electron Probe Microanalyzer ◽  
Biological Compatibility

The application of various materials in biomedical procedures has recently experienced rapid growth. One of the areas is the treatment of many of different types of bone-related diseases and disorders by using biodegradable polymer-ceramic composites. We have developed a material based on cryogel polyvinyl alcohol, mineralized with calcium phosphate. Composites were obtained by cyclic freezing-thawing, the synthesis of calcium phosphates was carried out in situ under the influence of microwave radiation with heating and stirring. The components of the composites were determined using the methods of IR-spectroscopy and scanning electron microscopy and electron probe microanalyzer, as well as their morphology and surface properties. The biological compatibility of the material was investigated in vivo for a Wistar rat. The assessment of the quality of bone formation between the cryogel-based implant and the damaged bone was carried out by computed tomography. An improvement in the consolidation of the bone defect is observed in the bone with the composite in comparison with the control bone.

scholarly journals Overview of Calcium Phosphates used in Biomimetic Oral Care

2018 ◽  
Vol 12 (1) ◽  
pp. 406-423 ◽  
Author(s):  
Frederic Meyer ◽  
Bennett T. Amaechi ◽  
Helge-Otto Fabritius ◽  
Joachim Enax
Keyword(s):  
Calcium Phosphates ◽  
Oral Care ◽  
Original Research ◽  
Preventive Dentistry ◽  
Human Teeth ◽  
Search Terms ◽  
Early Caries ◽  
Caries Lesions

Background:The use of biomimetic agents is an emerging field in modern oral care. Promising biomimetic substances for such applications are calcium phosphates, because their chemical composition is very similar to that of the mineral phase in human teeth, especially of natural enamel. Examples for their application include the remineralization of early caries lesions and repair of small enamel defects.Objective:This review provides an interdisciplinary view on calcium phosphates and their applications in biomimetic oral care. The aim of this work is to give an overview ofin vivoandin situstudies comparing several calcium phosphates in preventive dentistry that can be used as a knowledge base for the development of innovative alternative oral care concepts.Methods:Books, reviews, and original research papers with a focus onin vivoandin situstudies were included. The databases PubMed®and SciFinder®were used for literature search. Calcium phosphates that are frequently utilized in oral care products are covered in this review and were used as search terms alone and together with the following key words:in vivo,in situ, caries, clinical study, and remineralization. From 13,470 studies found, 35 studies complied with the inclusion criteria and were used for this review.Results:Publishedin vivoandin situstudies demonstrate calcium phosphates’ potential in enamel remineralization. However, more studies are needed to further substantiate existing results and to extend and refine the application of calcium phosphates in modern oral care.Conclusion:Calcium phosphates represent an innovative biomimetic approach for daily oral care because of their high similarity to natural enamel that will broaden the range of future treatments in preventive dentistry.

Octacalcium Phosphate as a Precursor in Biomineral Formation

1987 ◽  
Vol 1 (2) ◽  
pp. 306-313 ◽  
Author(s):  
W.E. Brown ◽  
N. Eidelman ◽  
B. Tomazic
Keyword(s):  
Thermogravimetric Analysis ◽  
Calcium Phosphates ◽  
Three Dimensional ◽  
Octacalcium Phosphate ◽  
Basic Form ◽  
Vacancy Defects ◽  
Impurity Ions

What are biominerals and how are they formed? It is usually assumed: (i) that the prototype for most apatitic biominerals is hydroxyapatite (OHAp), Ca5(PO4) 3OH; and (ii) that the OHAp structure has been modified by the presence of impurity ions and vacancy defects in specific OHAp lattice sites. The usual answer, at least implicitly, to the second question is that the apatitic mineral is formed directly by the precipitation of ions from the surrounding solution. Our answers are: (i) that apatitic biominerals are formed through a precursor mechanism in which octacalcium phosphate (OCP), Ca8H 2(PO4)6·5H2O, precipitates first and then hydrolyzes ireversibly in situ to a transition product intermediate to OCP and OHAp; and (ii) that this product, "octacalcium phosphate hydrolyzate" (OCPH), may contain (a) OHAp-like and OCP-like domains in varying amounts, (b) vacancy defects and impurity ions in lattice sites in these domains, and (c) various kinds of one-, two-, and three-dimensional defects which are not present in either the OHAp or the OCP lattice, these defects being formed during the in situ hydrolysis step. A calcification model of this type was first proposed in 1957, but full acceptance was delayed because most of the evidence was circumstantial and in vitro in nature. The situation has changed radically because of three unrelated studies that are in vivo in nature but lead to the same conclusion: I. 32P-pyrolysis studies of rat enamel: The results clearly demonstrated that an acidic calcium phosphate precursor was involved. II. Precipitation of calcium phosphates in serum. Ultrafiltered serum was equilibrated with brushite. Subsequent changes in the ionic concentrations revealed that OCP was formed at first and then hydrolyzed to a more basic form, OCPH, but never reached the solubility of OHAp. III. Physicochemical properties of cardiovascular biominerals: We recently characterized biominerals in cardiovascular deposits in an encompassing variety of ways. As an overall conclusion, OCPH was the prototype most compatible with the data [including indices of refraction, solubility, P2O74- formation on pyrolysis, thermogravimetric analysis (TGA) measurements, presence of water, and incorporation of CO32-, Na+, and Mg2+]. This calcification model has important consequences relative to all kinds of calcification and decalcification processes, including those of enamel.

In situ formation of biphasic calcium phosphates and their biological performance in vivo

2012 ◽  
Vol 38 (3) ◽  
pp. 1965-1974 ◽  
Author(s):  
Tae-Wan Kim ◽  
Young Min Park ◽  
Dong-Hyun Kim ◽  
Hyeong-Ho Jin ◽  
Keun-Koo Shin ◽  
...  
Keyword(s):  
Calcium Phosphates ◽  
In Situ Formation ◽  
Biological Performance

scholarly journals DESIGNING OF NOVEL TOPICAL IN SITU POLYMERIC FILM-FORMING SOLUTION SPRAY FORMULATION OF ANTIFUNGAL AGENT: IN VITRO ACTIVITY AND IN VIVO CHARACTERIZATION

2022 ◽  
pp. 169-184
Author(s):  
NABIL ABDULLAH ◽  
AMIT B. PATIL
Keyword(s):  
Ex Vivo ◽  
Skin Irritation ◽  
Inhibition Zone ◽  
Wistar Rat ◽  
Polymeric Film ◽  
Film Forming ◽  
Spray Formulation

Objective: Voriconazole (VCZ) is a broad-spectrum antifungal medication that works by inhibiting fungal Cytochrome P450, preventing fungi growth. The current study aims at developing and characterizing an antifungal in situ film-forming polymeric solution spray containing VCZ for use in topical drug delivery systems. Methods: Optimized VCZ in situ polymeric film formulation was evaluated for Fourier transform infrared spectroscopy (FTIR), differential scanning calorimeter (DSC), X-ray diffractometry (XRD), Scanning electron microscope (SEM), in vitro and in vivo, ex-vivo investigation using abdominal rat skin and stability studies. The in vivo antifungal activity of the advanced in situ film was examined in albino Wistar rats. Results: The optimized batch contained 22% Eudragit RS 100 (ERS) and 4% Sorbitol. Based on FTIR, XRD, SEM, and rheological studies. Formulation ingredients of VCZ loaded topical in situ polymeric film spray were observed to be compatible and showed no evidence of precipitation, deformation, or discoloration. Diffusion test (in vitro %), and ex-vivo drug diffusion % obtained 99.22%, and 97.45% respectively. The maximum inhibition zone was measured at 13±0.07 mm. The Wistar rat was employed as an animal model for skin irritation and antifungal studies. A study of short-term stability observed no significant modifications in the physical properties. Conclusion: The findings of the optimized VCZ topical in situ polymeric film spray formulation were satisfactory, demonstrating comparable improvement in superficial antifungal treatment.

scholarly journals A Chemical-Biological-Radio-Nuclear (CBRN) Filter can be Added to the Air-Outflow Port of a Ventilator to Protect a Home Ventilated Patient From Inhalation of Toxic Industrial Compounds

2018 ◽  
Vol 12 (6) ◽  
pp. 739-743
Author(s):  
Eliezer Be’eri ◽  
Simon Owen ◽  
Maurit Beeri ◽  
Scott R. Millis ◽  
Arik Eisenkraft
Keyword(s):  
Mechanical Ventilation ◽  
Terrorist Attacks ◽  
Home Mechanical Ventilation ◽  
Industrial Accidents ◽  
Entire Study ◽  
Industrial Compounds ◽  
Subjective Sensation

AbstractObjectivesChemical-biological-radio-nuclear (CBRN) gas masks are the standard means for protecting the general population from inhalation of toxic industrial compounds (TICs), for example after industrial accidents or terrorist attacks. However, such gas masks would not protect patients on home mechanical ventilation, as ventilator airflow would bypass the CBRN filter. We therefore evaluated in vivo the safety of adding a standard-issue CBRN filter to the air-outflow port of a home ventilator, as a method for providing TIC protection to such patients.MethodsEight adult patients were included in the study. All had been on stable, chronic ventilation via a tracheostomy for at least 3 months before the study. Each patient was ventilated for a period of 1 hour with a standard-issue CBRN filter canister attached to the air-outflow port of their ventilator. Physiological and airflow measurements were made before, during, and after using the filter, and the patients reported their subjective sensation of ventilation continuously during the trial.ResultsFor all patients, and throughout the entire study, no deterioration in any of the measured physiological parameters and no changes in measured airflow parameters were detected. All patients felt no subjective difference in the sensation of ventilation with the CBRN filter canister in situ, as compared with ventilation without it. This was true even for those patients who were breathing spontaneously and thus activating the ventilator’s trigger/sensitivity function. No technical malfunctions of the ventilators occurred after addition of the CBRN filter canister to the air-outflow ports of the ventilators.ConclusionsA CBRN filter canister can be added to the air-outflow port of chronically ventilated patients, without causing an objective or subjective deterioration in the quality of the patients’ mechanical ventilation. (Disaster Med Public Health Preparedness. 2018;12:739-743)

Fabrication of sliver nanoparticles/polyvinyl alcohol/gelatin ternary nanofiber mats for wound healing application

2020 ◽  
Vol 35 (2) ◽  
pp. 287-298
Author(s):  
Somaya Amer ◽  
Noha Attia ◽  
Samir Nouh ◽  
Mahmoud El-Kammar ◽  
Ahmed Korittum ◽  
...  
Keyword(s):  
Wound Healing ◽  
Polyvinyl Alcohol ◽  
Wound Dressings ◽  
Full Thickness ◽  
Microbial Invasion ◽  
Thickness Skin ◽  
Nanofiber Mats ◽  
Full Thickness Wound

Purpose In this study, we aimed to determine the regenerative and antimicrobial impact of the electrospun nanofiber mats, with/without silver nanoparticles (AgNPs), on full-thickness skin wounds in rabbits. Methods Polyvinyl alcohol was combined with gelatin to provide biocompatible electrospun binary nanofiber mats. AgNPs were added to the polyvinyl alcohol/gelatin mixture to obtain ternary nanofiber-AgNPs mats. Binary and ternary nanofiber mats were characterized by scanning electron microscopy before being applied as wound dressings in vivo. Subsequently, wound healing was evaluated. Results Both nanofiber/nanofiber-AgNPs mats improved the microscopic quality of the healed skin, albeit without obvious acceleration of the healing rate. As well, both types of nanofiber mats were able to combat microbial invasion into the wound bed. Conclusions Both binary polyvinyl alcohol/gelatin and ternary polyvinyl alcohol/gelatin/AgNPs nanofiber mats developed in the present study depicted similar regenerative and antimicrobial potential when applied as full-thickness wound dressing. However, in comparison to the binary nanofiber mats, no obvious synergistic effect was observed after loading nanofibers with AgNPs.

In vitro and in vivo polysaccharides assembly: ultrastructural and cytochemical study of growing plant cell wall components.

1978 ◽  
Vol 36 (2) ◽  
pp. 434-435
Author(s):  
D. Reis ◽  
B. Vian ◽  
J. C. Roland
Keyword(s):  
Cell Wall ◽  
Self Assembly ◽  
Plant Cell Wall ◽  
Higher Plants ◽  
Three Dimensional ◽  
Cytochemical Study ◽  
Wall Components

Wall morphogenesis in higher plants is a problem still open to controversy. Until now the possibility of a transmembrane control and the involvement of microtubules were mostly envisaged. Self-assembly processes have been observed in the case of walls of Chlamydomonas and bacteria. Spontaneous gelling interactions between xanthan and galactomannan from Ceratonia have been analyzed very recently. The present work provides indications that some processes of spontaneous aggregation could occur in higher plants during the formation and expansion of cell wall.Observations were performed on hypocotyl of mung bean (Phaseolus aureus) for which growth characteristics and wall composition have been previously defined.In situ, the walls of actively growing cells (primary walls) show an ordered three-dimensional organization (fig. 1). The wall is typically polylamellate with multifibrillar layers alternately transverse and longitudinal. Between these layers intermediate strata exist in which the orientation of microfibrils progressively rotates. Thus a progressive change in the morphogenetic activity occurs.

Three-Dimensional Subcellular Organization of Hepatocytes in Intact Liver: Simultaneous Visualization of Cytoskeletal and Membrane Markers by Confocal Microscopy

1996 ◽  
Vol 54 ◽  
pp. 288-289
Author(s):  
Greg V. Martin ◽  
Ann L. Hubbard
Keyword(s):  
Three Dimensional ◽  
Integral Membrane Proteins ◽  
Polarized Secretion ◽  
Microscope Images ◽  
Computer Aided ◽  
Intracellular Organelles ◽  
Cytoskeletal Elements ◽  
Simultaneous Visualization

The microtubule (MT) cytoskeleton is necessary for many of the polarized functions of hepatocytes. Among the functions dependent on the MT-based cytoskeleton are polarized secretion of proteins, delivery of endocytosed material to lysosomes, and transcytosis of integral plasma membrane (PM) proteins. Although microtubules have been shown to be crucial to the establishment and maintenance of functional and structural polarization in the hepatocyte, little is known about the architecture of the hepatocyte MT cytoskeleton in vivo, particularly with regard to its relationship to PM domains and membranous organelles. Using an in situ extraction technique that preserves both microtubules and cellular membranes, we have developed a protocol for immunofluorescent co-localization of cytoskeletal elements and integral membrane proteins within 20 µm cryosections of fixed rat liver. Computer-aided 3D reconstruction of multi-spectral confocal microscope images was used to visualize the spatial relationships among the MT cytoskeleton, PM domains and intracellular organelles.

Pengaruh Jenis Co-Solvent terhadap Rendemen dan Mutu Biodiesel secara Transesterifikasi In Situ Menggunakan Radiasi Gelombang Mikro

2016 ◽  
Vol 10 (2) ◽  
pp. 119-126
Author(s):  
Mahlinda Mahlinda ◽  
Fitriana Djafar
Keyword(s):  
Catalyst Concentration ◽  
Maximum Yield ◽  
Acid Value ◽  
Experimental Result ◽  
In Situ Transesterification ◽  
Yield And Quality ◽  
Solvent Type ◽  
Biodiesel Quality

The main purpose of this research was to observer effect co-solvent type (n-Hexane, chloroform and without co-solvent)  toward yield and quality of biodiesel via in situ transesterification process using microwave irradiation. The process was studied at microwave power 450 watt, reaction time 4 minutes, methanol to seed ratio 25:1 and catalyst concentration 5%. The physicochemical parameters of the biodiesel produced such as viscosity, density and acid value were analysed and compared with the SNI 7182-2012 standard. The experimental result showed the maximum yield biodiesel 78,32% obtained by using co-solvent chloroform.Test result of physicochemical properties (viscosity, density and acid value) of biodiesel products using co solvent n-Hexane, chloroform and without co solvent showed that these products conform to the SNI 7182-2012 standars. The type of co-solvent only affectedon biodiesel yield dan not affected on biodiesel quality (viscosity, density and acid value).  ABSTRAKTujuan penelitian ini adalah untuk mempelajari pengaruh jenis co-solvent (n-Hexane, chloroform dan tanpa co-solvent) terhadap rendemen dan mutu biodiesel secara trasesterifikasi in situ menggunakan radiasi gelombang mikro. Proses dilakukan pada daya gelombang mikro 450 watt, waktu reaksi 4 menit, perbandingan berat metanol terhadap bahan baku 25:1 dan jumlah katalis 5%. Parameter fisiko kimia dari produk biodiesel seperti viskositas, densitas dan angka asam di analisa dan dibandingkan dengan standar SNI 7182-2012 tentang biodiesel. Hasil penelitian menunjukkan rendemen maksimum biodiesel sebesar 78,32% diperoleh dengan menggunakan co-solvent chloroform. Hasil pengujian  karakteristik fisiko kimia (viskositas, densitas dan angka asam) dari produk biodiesel menggunakan co-solvent n-Hexane, chloroform dan tanpa co-solvent menunjukkan bahwa semua parameter ini masih memenuhi standar SNI 1782-2012 tentang biodiesel. Jenis co-solvent hanya berpengaruh pada rendemen biodiesel dan tidak berpengaruh terhadap mutu biodiesel (viskositas, densitas dan bilangan asam).Kata kunci: co-solvent, in situ transesterifikasi, microwave, rendemen, mutu   

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