Bioceramic Nanoparticles for Tissue Engineering
Harishkumar Madhyastha, Durgesh Nandini Chauhan in Nanopharmaceuticals in Regenerative Medicine, 2022
Nanosized bioceramic particles of calcium phosphates (CaPs) like nano-hydroxyapatite (nHAp) and nano-tricalcium phosphates (nTCP) have obtained specific interest in the development of biomaterials used for clinical applications specifically as restorative dental and orthopaedic implants. Different compounds of calcium phosphates such as hydroxyapatite (HAp), calcium tetraphosphate (Ca4P2O9), tricalcium phosphate (TCP) Ca3(PO4)2, and calcium hydroxyapatite Ca10(PO4)6(OH)2 can be produced by varying the atomic ratio of Ca/P from 1.5 to 2 (Ramay and Zhang 2004). Since the structure of calcium phosphate resembles the inorganic component of natural hard tissue, i.e. bone and teeth, and also they have typical biological responses such as good bioaffinity and enhancement of osseo-integration as well as successful clinical history, these ceramics are in high demand in the clinical field (Ebrahimi et al. 2019). However, the biological performance such as protein adsorption, angiogenesis, and vascularisation will totally depend on CaP particle composition, structure, morphology, and crystallite sizes (Zhou et al. 2013). Also, calcium phosphates are soluble under aqueous solution below pH 4.2, the property which makes it exploited during resorption of bone mineral by osteoclasts (bone remodelling) leading to the conditions of lysosomal degradation. Therefore, calcium phosphate nanoceramics are often applied for making scaffolds for solid bone tissue engineering (Ebrahimi et al. 2019).
Writing the Initial Parenteral Nutrition Order
Michael M. Rothkopf, Jennifer C. Johnson in Optimizing Metabolic Status for the Hospitalized Patient, 2023
From the prescriber’s perspective, we should recognize that the risk of calcium phosphate precipitation increases as the combined content of calcium and phosphorus increases. This is especially true when the PN volume decreases. As a rule of thumb, try to keep the sum of both to less than 45 (RxKinetics 2009). You can calculate the calcium/phosphorus solubility product by multiplying the total calcium added (in mEq) times the total phosphate used (in mmol) and dividing by the number of liters of final PN volume. The equation looks like this: Calcium/phosphorus solubility product = Total PN Ca++(mEq) × Total PN PO4 (mmol)/Total PN Volume (liters)
Engineering Bone Formation with Biologically Inspired Nanomaterials
Iniewski Krzysztof in Integrated Microsystems, 2017
Calcium phosphates such as hydroxyapatite (HA) and tricalciumphosphate are biocompatible, osteoconductive, and promote bone ingrowth, but the drawback is their low initial strength, which leads to difficulty in maintaining the composite within the defect. In order to overcome this issue, bioactive ceramics that harden in vivo such as calcium-deficient hydroxyapatite have been developed [22,23] that promote bone growth and have compressive strengths higher than that of cancellous bone [24,25]. Potential drawbacks of calcium phosphates are fatigue fractures that limit their use to skeletal tissues that are subject to uniform compressive loading [26]. Natural [27–30] and synthetic [31–37] reinforced with calcium phosphates exhibit compressive strengths in the range of 2–30 MPa, suitable for trabecular bone replacement. The addition of HA to drawn PLLA not only improved biodegradability and strength, but it also increased compatibility with the bone tissue.
Utility of calcium phosphate cement cranioplasty following supraorbital approach for tumor resection
Published in International Journal of Neuroscience, 2018
Rafey A. Feroze, Nitin Agarwal, Raymond F. Sekula
Calcium phosphate cement is a bioactive grafting material, available in the form of powder and, when mixed with a variety if pH neutral liquids, sets as hydroxyapatite. The brand used in the present case series (Cranios Reinforced, Synthes; 74 HydroSet, Stryker) consists of three components: the calcium phosphate powder, a bioresorable poly (lactide co-glycolide) polymer fibers to increase material strength and provide resistance to cracking and a sodium hyaluronate solution to enhance viscosity during mixing. The final solution is 4.0–5.0% carbonate with a Ca/P molar ration of 1.6, which is similar to bone composition. Soon after exposure to sodium hyaluronate solution, the hydroxyapatite forms a paste that can be deposited to fit any shape before it hardens [23]. After the cement has set, the final composition is similar to mineral bone. Thereby, it has been shown to be promising for grafting applications [24]. According to the manufacturer instructions, the calcium phosphate cement has the compression strength of 25 mPA after hardening [23].
Elevated admission serum calcium phosphate product as an independent risk factor for acute kidney injury in hospitalized patients
Published in Hospital Practice, 2019
Charat Thongprayoon, Wisit Cheungpasitporn, Michael A. Mao, Andrew M. Harrison, Stephen B. Erickson
The admission serum calcium and phosphorus levels, defined as the first serum calcium or phosphorus level within 24 hours of hospital admission, were collected. Calcium-phosphate product was calculated by calcium x phosphate. Sensitivity analysis of corrected serum calcium was also performed in patients with available serum albumin. Corrected calcium was calculated using the following formula: corrected calcium = (0.8 x (4 – patient’s serum albumin)) + easured serum calcium [29,30]. eGFR was derived using the CKD-EPI equation [31]. Chronic kidney disease (CKD) was defined as calculated eGFR < 60 mL/min/1.73 m2. The Charlson Comorbidity score was computed for co-morbidities at the time of admission [32]. Principal diagnoses were grouped based on admission ICD-9 codes (Supplemental Table 2).
Advances in pharmacotherapy for diabetic foot osteomyelitis
Published in Expert Opinion on Pharmacotherapy, 2021
Raju Ahluwalia, Jose Luiz Lázaro-Martínez, Ines Reichert, Nicola Maffulli
The principal types of biodegradable ceramics available for antibiotic delivery are based on either calcium sulfate or calcium phosphate (Tables 4 and 5). Within the calcium phosphate group, two main types exist: tricalcium phosphate and hydroxyapatite. Calcium sulfate has also been used as a bone graft material since 1892 [90], having a compressive strength equivalent to that of cancellous bone [91]. However, it is brittle and quickly loses its strength as it is hydrolyzed on its own and needs to be combined with another ceramic. Its use in DFO showed that 20 of 323 patients required further debridement before wound healing occurred [92], and another 20 patients required an amputation, 6 being below knee. Jogia et al. reported no recurrence or amputation following debridement of forefoot ulcers in 20 patients at 12-month follow-up with routine use of calcium sulfate impregnated with antibiotics [93]. Krause et al. found that 13 of 49 feet treated by trans-metatarsal amputation with calcium sulfate and tobramycin experienced a reduction in below knee amputation rates at an average follow-up of 28 months (8–52 months) [94].