silicon and Calcinosis

To conduct a new exploration and analysis of the ion and fatty acid levels of a medium in which calcified hydrophilic intraocular lenses (IOLs) are present.. Qingdao Eye Hospital of Shandong First Medical University, Qingdao, China.. Retrospective, laboratory observational case series.. 11 patients (11 eyes) who had implantation of foldable hydrophilic acrylic posterior IOLs were found to have opacification of the IOLs. In vivo and in vitro analyses included the evaluation of patients' clinical characteristics, microscopy, histological staining, energy dispersive X-ray spectroscopy (EDS), the ion level of the aqueous humor (AH) and preserving fluid (PF), and the fatty acid content of AH.. 10 of 11 cases were female with unilateral opacification, and 7 cases had both-eye cataract surgery, including 1 first eye and 6 second eyes with IOL opacification. 4 types of similar serial numbers were counted. The analysis of AH showed that the concentrations of phosphorus and silicon were elevated but that of calcium decreased, and an increased level of silicon was detected in 3 random PFs. The palmitic (C16:0) and stearic (C18:0) fatty acids were higher than the others in the AH. The EDS confirmed that the IOL surface deposits were composed of calcium, phosphate, and a small amount of silicon.. More silicon and higher C16:0 and C18:0 were found in the AH of patients with IOL opacification. New ideas and avenues have been proposed in the study of IOL opacification.

Topics: Calcinosis; Calcium; Female; Humans; Lens Implantation, Intraocular; Lenses, Intraocular; Male; Phacoemulsification; Postoperative Complications; Retrospective Studies; Silicon

Quantifying ion concentrations and mapping their intracellular distributions at high resolution can provide much insight into the formation of biomaterials. The key to achieving this goal is cryo-fixation, where the biological materials, tissues and associated solutions are rapidly frozen and preserved in a vitreous state. We developed a correlative cryo-Scanning Electron Microscopy (SEM)/Energy Dispersive Spectroscopy (EDS) protocol that provides quantitative elemental analysis correlated with spatial imaging of cryo-immobilized specimens. We report the accuracy and sensitivity of the cryo-EDS method, as well as insights we derive on biomineralization pathways in a foraminifer. Foraminifera are marine protozoans that produce Mg-containing calcitic shells and are major calcifying organisms in the oceans. We use the cryo-SEM/EDS correlative method to characterize unusual Mg and Ca-rich particles in the cytoplasm of a benthic foraminifer. The Mg/Ca ratio of these particles is consistently lower than that of seawater, the source solution for these ions. We infer that these particles are involved in Ca ion supply to the shell. We document the internal structure of the MgCa particles, which in some cases include a separate Si rich core phase. This approach to mapping ion distribution in cryo-preserved specimens may have broad applications to other mineralized biomaterials.. Ions are an integral part of life, and some ions play fundamental roles in cell metabolism. Determining the concentrations of ions in cells and between cells, as well as their distributions at high resolution can provide valuable insights into ion uptake, storage, functions and the formation of biomaterials. Here we present a new cryo-SEM/EDS protocol that allows the mapping of different ion distributions in solutions and biological samples that have been cryo-preserved. We demonstrate the value of this novel approach by characterizing a novel biogenic mineral phase rich in Mg found in foraminifera, single celled marine organisms. This method has wide applicability in biology, and especially in understanding the formation and function of mineral-containing hard tissues.

Topics: Biocompatible Materials; Calcinosis; Calcium; Calcium Carbonate; Calibration; Cryoelectron Microscopy; Cryopreservation; Cytoplasm; Foraminifera; Ions; Magnesium; Microscopy, Electron, Scanning; Minerals; Oceans and Seas; Reproducibility of Results; Seawater; Silicon; Spectrometry, X-Ray Emission; Spectrum Analysis, Raman

To investigate the feasibility of detecting breast microcalcification (μCa) with a dedicated breast computed tomography (CT) system based on energy-resolved photon-counting silicon (Si) strip detectors.. The proposed photon-counting breast CT system and a bench-top prototype photon-counting breast CT system were simulated using a simulation package written in matlab to determine the smallest detectable μCa. A 14 cm diameter cylindrical phantom made of breast tissue with 20% glandularity was used to simulate an average-sized breast. Five different size groups of calcium carbonate grains, from 100 to 180 μm in diameter, were simulated inside of the cylindrical phantom. The images were acquired with a mean glandular dose (MGD) in the range of 0.7-8 mGy. A total of 400 images was used to perform a reader study. Another simulation study was performed using a 1.6 cm diameter cylindrical phantom to validate the experimental results from a bench-top prototype breast CT system. In the experimental study, a bench-top prototype CT system was constructed using a tungsten anode x-ray source and a single line 256-pixels Si strip photon-counting detector with a pixel pitch of 100 μm. Calcium carbonate grains, with diameter in the range of 105-215 μm, were embedded in a cylindrical plastic resin phantom to simulate μCas. The physical phantoms were imaged at 65 kVp with an entrance exposure in the range of 0.6-8 mGy. A total of 500 images was used to perform another reader study. The images were displayed in random order to three blinded observers, who were asked to give a 4-point confidence rating on each image regarding the presence of μCa. The μCa detectability for each image was evaluated by using the average area under the receiver operating characteristic curve (AUC) across the readers.. The simulation results using a 14 cm diameter breast phantom showed that the proposed photon-counting breast CT system can achieve high detection accuracy with an average AUC greater than 0.89 ± 0.07 for μCas larger than 120 μm in diameter at a MGD of 3 mGy. The experimental results using a 1.6 cm diameter breast phantom showed that the prototype system can achieve an average AUC greater than 0.98 ± 0.01 for μCas larger than 140 μm in diameter using an entrance exposure of 1.2 mGy.. The proposed photon-counting breast CT system based on a Si strip detector can potentially offer superior image quality to detect μCa with a lower dose level than a standard two-view mammography.

Topics: Area Under Curve; Breast; Calcinosis; Calcium Carbonate; Computer Simulation; Humans; Mammography; Models, Biological; Phantoms, Imaging; Photons; Radiation Dosage; ROC Curve; Silicon; Software; Tomography, X-Ray Computed

Calcific band keratopathy (CBK) is a degenerative condition resulting in the deposition of calcium salts in the superficial layers of the cornea and causing significant visual disturbance and pain of the affected eye. Unfortunately, the amount of CBK precipitates recovered from the affected eye is very small therefore; it would be beneficial to prepare a synthetic material mimicking CBK material to further the development of therapeutics. Analyses of biological samples recovered from patients show the presence of silicon in addition to calcium, as well as a distinctive fused spherical morphology. This prompted us to study the reaction of various sources of silicon (fumed silica, silicic acid, and silicone oil) with CaCO(3) under a range of reaction conditions to gain an understanding of the formation of CBK. A silicon source alone was not found to be responsible for the fused spherical morphology, and a third component, a polar surfactant-like molecule such as sodium dodecyl sulfate or tetradecylphosphonic acid, was also required. The effects of silicon:calcium ratio and reaction time have been studied. The reaction of fumed silica with CaCO(3) in presence of sodium dodecyl sulfate results in the formation of spherical shapes resembling the structures and chemical composition observed in the eye samples, while no such structures were observed in the absence of silicon. Samples closely resembling human samples were also formed from the reaction of silicone oil with CaCO(3) in the presence of tetradecylphosphonic acid. Samples were characterized by SEM, XRD, and XPS and Raman spectroscopy.

Topics: Alkanes; Biocompatible Materials; Calcinosis; Calcium Carbonate; Corneal Diseases; Humans; Materials Testing; Molecular Structure; Organophosphonates; Phosphorous Acids; Silicic Acid; Silicon; Silicon Dioxide; Sodium Dodecyl Sulfate; Surface-Active Agents

To describe the association between calcification of older and newer designs of silicone intraocular lenses (IOLs) and asteroid hyalosis.. Case series with clinicopathologic correlation.. Sixteen silicone IOLs explanted because of decreased visual acuity associated with opacifying deposits on the posterior optic surface.. All 16 lenses underwent gross and light microscopic analyses. Selected lenses underwent alizarin red staining or scanning electron microscopy coupled with energy dispersive x-ray spectroscopy for elemental composition. Clinical data in each case were obtained by a questionnaire sent to the explanting surgeons. Clinical data in relation to 111 hydrophilic acrylic lenses explanted because of calcification also were assessed for comparison.. Deposit morphologic features and location were evaluated under gross and light microscopy. The calcified nature of the deposits was assessed by histochemical staining and surface analyses. Clinical data obtained included age at IOL implantation, gender, implantation and explantation dates, as well as history of neodymium:yttrium-aluminum-garnet laser treatment. The presence of asteroid hyalosis in the affected eye was investigated for the explanted silicone and hydrophilic acrylic lenses.. The 16 lenses were of 8 designs manufactured from different silicone materials, which were explanted 9.21+/-3.66 years after implantation. Neodymium:yttrium-aluminum-garnet laser applications performed in 12 cases partially removed deposits from the lens, followed by a gradual increase in their density after the procedures. The presence of asteroid hyalosis was confirmed in 13 cases; no notes regarding this condition were found in patient charts in the other 3 cases. The deposits were only on the posterior optic surface of the silicone lenses and were composed of calcium and phosphate. A history of asteroid hyalosis was not found in relation to any of the 111 cases of postoperative calcification of hydrophilic acrylic lenses.. Including this current series, there are 22 cases of calcification of silicone lenses involving 8 designs manufactured from different silicone materials described in the literature. The presence of asteroid hyalosis was confirmed in 86.4% of cases. These findings may be added to the list of pros and cons surgeons consider when selecting or recommending an IOL.

Topics: Acrylic Resins; Aged; Aged, 80 and over; Calcinosis; Calcium; Device Removal; Eye Diseases; Female; Humans; Lenses, Intraocular; Male; Microscopy, Electron, Scanning; Middle Aged; Phosphates; Prosthesis Design; Prosthesis Failure; Silicon; Silicone Elastomers; Sodium; Spectrometry, X-Ray Emission; Surveys and Questionnaires; Visual Acuity; Vitreous Body

To verify the presence of the element silicon on hydrophilic acrylic intraocular lenses (IOLs) explanted because of calcification.. Interventional case series with clinicopathological correlation.. Twenty explanted IOLs with surface deposits (MemoryLens), and 20 with deposits mostly within their optic substance (SC60B-OUV and Aqua-Sense; 10 each) were used. After gross, microscopic, and histochemical analyses to confirm the presence of deposits, the lenses underwent scanning electron microscopy (SEM) with energy dispersive x-ray spectroscopy (EDS) for elemental composition, on the external surface of MemoryLens IOLs, and on the surface and internal substance of SC60B-OUV and Aqua-Sense IOLs. The weight percentage of the element silicon was obtained at the level of deposits, and at adjacent deposit-free areas in all lenses.. Scanning electron microscopy (SEM) coupled with EDS confirmed that the composition of the deposits was calcium/phosphate in all cases. The element silicon was found in all 40 lenses, on all areas analyzed. The silicon weight percentage was higher at the level of the deposits. The presence of aluminum on five MemoryLens IOLs, and in most of the SC60B-OUV and Aqua-Sense lenses might be related to scattering from the aluminum mounting stubs used for surface analyses.. Silicone compounds have been implicated in the calcification of another hydrophilic acrylic design (Hydroview). They may also have a role in the calcification of other hydrophilic acrylic IOLs. Further investigation on the relationship between the presence of the element silicon and the silicone compounds found on calcified hydrophilic acrylic lenses is necessary.

Topics: Acrylic Resins; Calcinosis; Calcium Phosphates; Device Removal; Electron Probe Microanalysis; Equipment Failure Analysis; Humans; Lenses, Intraocular; Microscopy, Electron, Scanning; Prosthesis Failure; Silicon

Recently, calcification was observed on implanted intraocular lens (IOL) surfaces when viscoelastic substances were applied during surgery. To elucidate the mechanisms of mineral formation, the crystallization of calcium phosphates on IOL surfaces was studied in vitro with nanomolar sensitivity using a constant composition method. Three different commercial viscoelastic materials (Viscoat, OcuCoat, and Amvisc Plus) were investigated and it was found that some IOLs treated with Viscoat or Amvisc Plus induced the nucleation and growth of octacalcium phosphate crystallites under biological conditions. After treatments, the IOL surfaces became more hydrophilic probably because of the high viscoelastic phosphate and carboxylate contents. In contrast to Viscoat, the use of OcuCoat during surgery resulted in virtually no octacalcium phosphate nucleations. Calcification studies of IOL surfaces treated with fatty acids, which are present in human aqueous humor, suggest that hydrophobic cyclic silicones adsorbed on the IOL surfaces interact strongly with hydrophobic hydrocarbon chains of the fatty acids, creating a layer of amphiphiles oriented with functional carboxylate groups exposed to the aqueous solution and serving as active calcification sites.

Topics: Calcinosis; Calcium Phosphates; Crystallization; Cyclization; Fatty Acids; Lenses, Intraocular; Microscopy, Electron, Scanning; Molecular Structure; Silicon

Polarizing microscopy (PM), scanning electron microscopy (SEM), x-ray dispersive analysis (EDAX), x-ray diffraction (XRD), and infrared spectrometry (IR) were used to study the following pathological mineralizations: calcifications and silicon(Si)-bearing mineralizations in cerebral tissue from an epileptic child; traces of Si-bearing particles in periprosthesic mammarian tissue, and calcifications in capsular mammarian tissue from a patient with a silicone gel mammarian implant, and 2 calcium-bearing compounds, a typical apatitic calcification, and a nonphosphorous-bearing calcification in arterial tissues. In this tissue we also found Si-bearing particles due to an artifact from glassware.

Topics: Aged; Apatites; Arteries; Artifacts; Brain Diseases; Breast; Breast Diseases; Breast Implants; Cadaver; Calcinosis; Child; Electron Probe Microanalysis; Epilepsy; Female; Foreign Bodies; Glass; Humans; Lymph Nodes; Microscopy, Electron, Scanning; Microscopy, Polarization; Middle Aged; Prostheses and Implants; Silicon; Silicone Gels; Spectrophotometry, Infrared; Vascular Diseases; X-Ray Diffraction

The crystalline structure in calcified deposits of DBA/2 mice was analysed, because understanding this is essential in assessing the significance of this species as an animal model for spontaneous soft-tissue mineralization. In order to remove the thin soft tissue which covers the lesion, the samples were bombarded with an argon beam. The uncoated samples were analysed with an electron-probe microanalyser. The deposits were composed of a calcium phosphate material. At a higher magnification, smaller particles surrounding these large deposits were found. There were three types of particles: rod-shaped (calcium phosphate), polygonal (silicate) and round (about 1 microns dia).

Topics: Animals; Calcinosis; Calcium Phosphates; Cardiomyopathies; Electron Probe Microanalysis; Heart Ventricles; Male; Mice; Mice, Inbred DBA; Myocardium; Silicon; Tongue; Tongue Diseases

Ninety-seven surgically excised natural cardiac valves were examined by scanning electron microscopy and x-ray energy spectroscopy to assess the occurrence of crystalline deposits that contain the element silicon. Valves examined included 33 mitral valves, 63 aortic valves, and 1 tricuspid valve. To reduce the possibility of surface contamination, the deep layers of some valves were examined after exposure by fracture of the valve. Crystalline material containing silicon was observed in the deep tissue. Such crystalline material was sometimes entwined within subendothelial fibers. Crystalline deposits that contained silicon were associated with 34 of 97 of these valves (35%). Among the 34 valves that showed silicon, 24 (71%) also showed microdeposits of calcific material. In view of evidence that silicon may participate in the calcification of bone, and is found in the intima of arteries, a role for this element in ectopic calcification of valves may exist.

Topics: Adult; Aged; Aortic Valve; Calcinosis; Calcium; Crystallization; Female; Heart Valve Diseases; Heart Valves; Humans; Male; Microscopy, Electron, Scanning; Middle Aged; Mitral Valve; Silicon; Spectrum Analysis; Tricuspid Valve; X-Rays

Nephrocalcinosis with a deposition of aluminum and silicon has been previously reported in uremic rats. To clarify the origin of these elements thin sections of renal cortex were examined by means of electron microscopy and energy dispersive x-ray microanalysis. Studies were performed on subtotally nephrectomized rats (SNX) and sham-operated control animals. Electron microscopy of proximal tubular epithelial cells in SNX rats unlike control rats revealed severe mitochondrial disorganization; irregularity of the tubular basement membrane which exhibited various inclusions; and lamellar bodies within the brush border membrane. On x-ray microanalysis disorganized mitochondria contained calcium and silicon, while secondary lysosomes displayed aluminum and silicon. The tubular basement membrane of SNX rats, as well as lamellar body-like inclusions within the brush border contained calcium, aluminum and silicon together. It is suggested that lysosomal and mitochondrial interaction in proximal tubular cells of uremic rats may contribute to the deposition of calcium together with aluminum and silicon in the renal parenchyma, resulting in nephrocalcinosis.

Topics: Aluminum; Animals; Calcinosis; Calcium; Eating; Electron Probe Microanalysis; Kidney; Male; Microscopy, Electron; Rats; Silicon; Tissue Distribution; Uremia

Topics: Aluminum; Calcification, Physiologic; Calcinosis; Calcium; Copper; Dental Calculus; Humans; Iron; Lasers; Light; Magnesium; Phosphorus; Silicon; Spectrum Analysis; Zinc

Topics: Arteries; Calcification, Physiologic; Calcinosis; Humans; Osteoporosis; Silicon