-
Journal of Orthopaedic Surgery and... Jan 2024Injectable bone cement is commonly used in clinical orthopaedics to fill bone defects, treat vertebral compression fractures, and fix joint prostheses during joint...
BACKGROUND
Injectable bone cement is commonly used in clinical orthopaedics to fill bone defects, treat vertebral compression fractures, and fix joint prostheses during joint replacement surgery. Poly(propylene fumarate) (PPF) has been proposed as a biodegradable and injectable alternative to polymethylmethacrylate (PMMA) bone cement. Recently, there has been considerable interest in two-dimensional (2D) black phosphorus nanomaterials (BPNSs) in the biomedical field due to their excellent photothermal and osteogenic properties. In this study, we investigated the biological and physicochemical qualities of BPNSs mixed with PPF bone cement created through thermal cross-linking.
METHODS
PPF was prepared through a two-step process, and BPNSs were prepared via a liquid phase stripping method. BP/PPF was subsequently prepared through thermal cross-linking, and its characteristics were thoroughly analysed. The mechanical properties, cytocompatibility, osteogenic performance, degradation performance, photothermal performance, and in vivo toxicity of BP/PPF were evaluated.
RESULTS
BP/PPF exhibited low cytotoxicity levels and mechanical properties similar to that of bone, whereas the inclusion of BPNSs promoted preosteoblast adherence, proliferation, and differentiation on the surface of the bone cement. Furthermore, 200 BP/PPF demonstrated superior cytocompatibility and osteogenic effects, leading to the degradation of PPF bone cement and enabling it to possess photothermal properties. When exposed to an 808-nm laser, the temperature of the bone cement increased to 45-55 °C. Furthermore, haematoxylin and eosin-stained sections from the in vivo toxicity test did not display any anomalous tissue changes.
CONCLUSION
BP/PPF exhibited mechanical properties similar to that of bone: outstanding photothermal properties, cytocompatibility, and osteoinductivity. BP/PPF serves as an effective degradable bone cement and holds great potential in the field of bone regeneration.
Topics: Humans; Osteogenesis; Bone Cements; Phosphorus; Fractures, Compression; Spinal Fractures; Biocompatible Materials; Fumarates; Polypropylenes
PubMed: 38291442
DOI: 10.1186/s13018-024-04566-6 -
Biomedical Engineering Online Jan 2024Functional electrical stimulation (FES) can be used in rehabilitation to aid or improve function in people with paralysis. In clinical settings, it is common practice to...
BACKGROUND
Functional electrical stimulation (FES) can be used in rehabilitation to aid or improve function in people with paralysis. In clinical settings, it is common practice to use transcutaneous electrodes to apply the electrical stimulation, since they are non-invasive, and can be easily applied and repositioned as necessary. However, the current electrode options available for transcutaneous FES are limited and can have practical disadvantages, such as the need for a wet interface with the skin for better comfort and performance. Hence, we were motivated to develop a dry stimulation electrode which could perform equivalently or better than existing commercially available options.
METHODS
We manufactured a thin-film dry polymer nanocomposite electrode, characterized it, and tested its performance for stimulation purposes with thirteen healthy individuals. We compared its functionality in terms of stimulation-induced muscle torque and comfort level against two other types of transcutaneous electrodes: self-adhesive hydrogel and carbon rubber. Each electrode type was also tested using three different stimulators and different intensity levels of stimulation.
RESULTS
We found the proposed dry polymer nanocomposite electrode to be functional for stimulation, as there was no statistically significant difference between its performance to the other standard electrodes. Namely, the proposed dry electrode had comparable muscle torque generated and comfort level as the self-adhesive hydrogel and carbon rubber electrodes. From all combinations of electrode type and stimulators tested, the dry polymer nanocomposite electrode with the MyndSearch stimulator had the most comfortable average rating.
CONCLUSIONS
The dry polymer nanocomposite electrode is a durable and flexible alternative to existing self-adhesive hydrogel and carbon rubber electrodes, which can be used without the addition of a wet interfacing agent (i.e., water or gel) to perform as well as the current electrodes used for stimulation purposes.
Topics: Humans; Resin Cements; Rubber; Electric Stimulation; Hydrogels; Electrodes; Carbon
PubMed: 38279147
DOI: 10.1186/s12938-024-01200-8 -
Scientific Data Jan 2024Diffuse reflectance spectroscopy (DRS) has been extensively studied in both preclinical and clinical settings for multiple applications, notably as a minimally invasive...
Diffuse reflectance spectroscopy (DRS) has been extensively studied in both preclinical and clinical settings for multiple applications, notably as a minimally invasive diagnostic tool for tissue identification and disease delineation. In this study, extended-wavelength DRS (EWDRS) measurements of ex vivo tissues ranging from ultraviolet through visible to the short-wave infrared region (355-1919 nm) are presented in two datasets. The first dataset contains labelled EWDRS measurements collected from bone cement samples and ovine specimens including 10 tissue types commonly encountered in orthopedic surgeries for data curation purposes. The other dataset includes labelled EWDRS measurements of primarily bone structures at different depths during stepwise drilling into intact porcine skulls until plunging into the cranial cavity. The raw data with code for pre-processing and calibration is publicly available for reuse on figshare. The datasets can be utilized not only for exploratory purposes in machine learning model construction, but also for knowledge discovery in the orthopedic domain to identify important features for surgical guidance, extract physiological parameters and provide diagnostic insights.
Topics: Animals; Machine Learning; Sheep; Spectrum Analysis; Swine; Bone and Bones; Orthopedic Procedures
PubMed: 38278822
DOI: 10.1038/s41597-024-02972-3 -
Journal of Clinical Medicine Jan 2024Cementless primary stems in revision hip arthroplasties may be conservative options to preserve bone stock and provide adequate reconstruction of the hip biomechanics.... (Review)
Review
Cementless primary stems in revision hip arthroplasties may be conservative options to preserve bone stock and provide adequate reconstruction of the hip biomechanics. However, there is still little evidence about indications, limitations, and outcomes. This narrative review showed that conventional standard stems were adopted in different revision settings, up to Paprosky IIIA grade bone defects. In cases of acceptable metaphyseal bone stock, when a scratch fit of at least 4 cm can be achieved, a conventional cementless stem may be an adequate solution. Mid-term clinical and radiographic outcomes and survival rates were similar to long revision stems, whereas complications, surgical time, and costs were lower among conventional stems. However, unsuitable contexts for conventional stems included canal diameters larger than 18 mm and failed revision stems with cortical weakening. Even short stems can be considered in revisions, in order to preserve bone stock and stay proximal to femoral remodeling zones and bone/cement plugs. Short stems were successfully adopted up to Paprosky IIIA bone defects, achieving mid-term survival rates not inferior to long revision stems. Ageing, osteoporosis, and intraoperative femoral fractures were the main negative prognostic factors. In very select cases, a downsizing technique (from longer to shorter stems) may be adopted to simplify the procedure and reduce complications.
PubMed: 38276110
DOI: 10.3390/jcm13020604 -
Frontiers in Physiology 2023Upon endoplasmic reticulum (ER) stress, inositol-requiring enzyme 1 (IRE1) is activated, which subsequently converts an unspliced X-box binding protein 1 () mRNA to a...
Upon endoplasmic reticulum (ER) stress, inositol-requiring enzyme 1 (IRE1) is activated, which subsequently converts an unspliced X-box binding protein 1 () mRNA to a spliced mRNA that encodes a potent XBP1S transcription factor. XBP1S is essential for relieving ER stress and secretory cell differentiation. We previously established ; mice that constitutively expressed XBP1S in the -expressing cells as well as in the cells derived from the -expressing cells. In this study, we analyzed the dental phenotype of ; mice. We first generated a mutant minigene that corresponds to the recombinant allele (the allele that has undergone Cre-mediated recombination) and confirmed that the minigene expressed XBP1S that does not require IRE1α activation . Consistently, immunohistochemistry showed that XBP1S was constitutively expressed in the odontoblasts and other dental pulp cells in ; mice. Plain X-ray radiography and µCT analysis revealed that constitutive expression of XBP1S altered the dental pulp chamber roof- and floor-dentin formation, resulting in a significant reduction in dentin/cementum formation in ; mice, compared to age-matched control mice. However, there is no significant difference in the density of dentin/cementum between these two groups of mice. Histologically, persistent expression of XBP1S caused a morphological change in odontoblasts in ; mice. Nevertheless, hybridization and immunohistochemistry analyses showed that continuous expression of XBP1S had no apparent effects on the expression of the and genes. In conclusion, these results support that sustained production of XBP1S adversely affected odontoblast function and dentin formation.
PubMed: 38274041
DOI: 10.3389/fphys.2023.1319954 -
Pharmaceutics Jan 2024Surgical site infections (SSIs) after spinal surgery present significant challenges, including poor antibiotic penetration and biofilm formation on implants, leading to...
Surgical site infections (SSIs) after spinal surgery present significant challenges, including poor antibiotic penetration and biofilm formation on implants, leading to frequent treatment failures. Polymethylmethacrylate (PMMA) is widely used for localized drug delivery in bone infections, yet quantifying individual drug release kinetics is often impractical. This retrospective study analyzed 23 cases of deep SSIs (DSSIs) following spinal surgery treated with antibiotic-loaded PMMA. A mathematical model estimated personalized drug release kinetics from PMMA, considering disease types, pathogens, and various antibiotics. The study found that vancomycin (VAN), ceftriaxone (CRO), and ceftazidime (CAZ) reached peak concentrations of 15.43%, 15.42%, and 15.41%, respectively, within the first two days, which was followed by a lag phase (4.91-4.92%) on days 2-3. On days 5-7, concentrations stabilized, with CRO at 3.22% and CAZ/VAN between 3.63% and 3.65%, averaging 75.4 µg/cm. Key factors influencing release kinetics include solubility, diffusivity, porosity, tortuosity, and bead diameter. Notably, a patient with a low glomerular filtration rate (ASA IV) was successfully treated with a shortened 9-day intravenous VAN regimen, avoiding systemic complications. This study affirms the effectiveness of local drug delivery systems (DDS) in treating DSSIs and underscores the value of mathematical modeling in determining drug release kinetics. Further research is essential to optimize release rates and durations and to mitigate risks of burst release and tissue toxicity.
PubMed: 38258104
DOI: 10.3390/pharmaceutics16010094 -
Journal of Clinical Medicine Jan 2024Symptomatic osteoporotic compression fractures are commonly addressed through vertebroplasty and kyphoplasty. However, cement leakage poses a significant risk of...
Symptomatic osteoporotic compression fractures are commonly addressed through vertebroplasty and kyphoplasty. However, cement leakage poses a significant risk of neurological damage. We introduced "aspiration percutaneous kyphoplasty", also known as "decompressed kyphoplasty", as a method to mitigate cement leakage and conducted a comparative analysis with high viscosity cement vertebroplasty. We conducted a retrospective study that included 136 patients with single-level osteoporotic compression fractures. Among them, 70 patients underwent high viscosity cement vertebroplasty, while 66 patients received decompressed percutaneous kyphoplasty with low-viscosity cement. Comparison parameters included cement leakage rates, kyphotic angle alterations, and the occurrence of adjacent segment fractures. The overall cement leakage rate favored the decompressed kyphoplasty group (9.1% vs. 18.6%), although statistical significance was not achieved ( = 0.111). Nonetheless, the risk of intradiscal leakage significantly reduced in the decompressed kyphoplasty cohort ( = 0.011), which was particularly evident in cases lacking the preoperative cleft sign on X-rays. Kyphotic angle changes and the risk of adjacent segment collapse exhibited similar outcomes ( = 0.739 and 0.522, respectively). We concluded that decompressed kyphoplasty demonstrates efficacy in reducing intradiscal cement leakage, particularly benefiting patients without the preoperative cleft sign on X-rays by preventing intradiscal leakage.
PubMed: 38256479
DOI: 10.3390/jcm13020345 -
Medicina (Kaunas, Lithuania) Jan 2024: Caredyne ZIF-C is a novel, capsule-mixed zinc-containing prototype glass ionomer cement (GIC). Zinc ions are reported to inhibit root dentin demineralization, dentin... (Randomized Controlled Trial)
Randomized Controlled Trial
: Caredyne ZIF-C is a novel, capsule-mixed zinc-containing prototype glass ionomer cement (GIC). Zinc ions are reported to inhibit root dentin demineralization, dentin collagen degradation, bacterial growth, acid production, and in vitro bacterial biofilm formation. However, the effectiveness of GICs against initial root caries lesions is unclear. Therefore, this study aimed to evaluate the efficacy of GICs, especially the new zinc-containing Caredyne ZIF-C GIC, as tooth-coating materials in patients with initial active root caries. : A total of 58 lesions in 47 older adults (age > 65 years) were randomly allocated to one of the following three groups: Caredyne ZIF-C, Fuji VII (a conventional GIC), and sodium fluoride (NaF). All the lesions were treated with the assigned materials without removing the infected dentin, and the rates of dental plaque attachment and coating material fall-out were evaluated after 3, 6, and 12 months. The failure rate was defined as the number of teeth that needed restoration due to caries progression. : The plaque attachment rates tended to be lower in the material-coated root surfaces than in the healthy exposed root surfaces after 3, 6, and 12 months, although the differences among the three groups were not significant. Moreover, the coating material fall-out rate tended to be lower in the Caredyne ZIF-C group than in the Fuji VII group. There was no significant difference in the failure rate among the three groups at the 12 months mark. : Though this pilot study offers a new direction for suppressing the progression of initial active root caries by controlling plaque attachment using GICs including Caredyne ZIF-C, clinical studies with a larger sample size are needed.
Topics: Humans; Aged; Root Caries; Pilot Projects; Dental Caries; Health Status; Zinc
PubMed: 38256410
DOI: 10.3390/medicina60010150 -
Materials (Basel, Switzerland) Jan 2024This study investigates the improvement in the compressive strength of cellulose/cement-based composites. Methyl cellulose (MC), carboxymethyl cellulose (CMC), and...
This study investigates the improvement in the compressive strength of cellulose/cement-based composites. Methyl cellulose (MC), carboxymethyl cellulose (CMC), and hydroxypropyl cellulose (HPMC) are separately used as the cellulose phase with different wt%. Graphene oxide (GO) and zoledronic acid (ZOL) are used as additives for bone regeneration for various formulations. Utilizing Extreme Gradient Boosting (XGB) modeling, this research demonstrates the roles of the choice of the cellulose phase, wt% of cement phase, % gelatin, % citric acid, degradation time, and concentration of GO and ZOL in influencing compressive strength. The XGB regression model, with an R value of 0.99 (~1), shows the predictive power of the model. Feature importance analysis demonstrates the significance of cellulose choice and the addition of chitosan in enhancing compressive strength. The correlation heatmap reveals positive associations, emphasizing the positive influence of HPMC and CMC compared with MC and the substantial impact of chitosan and citric acid on compressive strength. The model's predictive accuracy is validated through predicted compressive strength values with experimental observations, providing insights for optimizing cellulose-reinforced cements and enabling tailored material design for enhanced mechanical performance.
PubMed: 38255542
DOI: 10.3390/ma17020374 -
IScience Jan 2024This study examines the effect of proteins on the binding property and microstructure of enzymatic-induced calcium carbonate precipitation (EICP) in cementitious...
This study examines the effect of proteins on the binding property and microstructure of enzymatic-induced calcium carbonate precipitation (EICP) in cementitious environment. The protein modified precipitates generally demonstrated improved binding to a glass slide surface or cement paste surface compared to the control precipitate. A marked decrease in the amount and binding strength of the precipitates in the cementitious environment was observed due to a reduction in the urease enzyme activity. The protein modified precipitates exhibited noticeable improvement compared to the control precipitate in cementitious environment which could arise from the ability of the proteins to partially shield urease from the negative effect of high pH. The protein gel network formation due to the complexation between the proteins and Ca provides nucleation sites for CaCO crystallization. The FTIR, SEM, TGA, and XRD results indicated that vaterite is the dominant polymorph in cementitious environment compared to calcite in deionized water.
PubMed: 38235339
DOI: 10.1016/j.isci.2023.108743