17 research outputs found
Developing A Synthetic Composite Membrane For Cleft Palate Repair
An oronasal fistula is a passage between the oral and nasal cavity. Currently, surgical procedures use mucosal flaps or collagen grafts to make a barrier between oral and nasal cavities. Our aim was to develop a cell-free synthetic repair material for closure of nasal fistulas. We surface functionalized electrospun polyurethane (PU) and poly-L-lactic acid (PLLA) and composite polymer (PU-PLLA) membranes with acrylic acid through plasma polymerization. Membranes were treated in a layer-by-layer approach to develop highly charged electrostatic layer that could bind heparin as a pro-angiogenic glycosaminoglycan. The properties were evaluated through physical, chemical, and mechanical characterization techniques. Cytotoxicity was tested with MC3T3 pre-osteoblast cell lines for 3, 7, and 14 days, and vasculogenesis was assessed by implantation into the chorio-allantoic membrane in chick embryos for 7 days. In vivo biocompatibility was assessed by subcutaneous implantation in rats for 1, 3, and 6 weeks. The membranes consisted of random fibers of PLLA-PU with fiber diameters of 0.47 and 0.12 μm, respectively. Significantly higher cell proliferation and migration of MC3T3 cells at 3, 7, and 14 days were shown on plasma-coated membranes compared with uncoated membranes. Further, it was found that plasma-coated membranes were more angiogenic than controls. In vivo implantation of membranes in rats did not reveal any gross toxicity to the materials, and wound healing was comparable with the native tissue repair (sham group). We therefore present a plasma-functionalized electrospun composite polymer membrane for use in the treatment of fistulas. These membranes are flexible, non-cytotoxic, and angiogenic, and we hope it should lead to permanent closure of oronasal fistula
Ceramic Stereolithography of Bioactive Glasses: Influence of Resin Composition on Curing Behavior and Green Body Properties
Herein we report on the preparation of a bioactive glass (BAG)-based photocurable resin for the additive manufacturing of BAG scaffolds with high filler loadings. The preparation of glass/ceramics resins for stereolithography with high filler loading is always a challenge, especially for fillers with a high refractive index variance. Various photocurable resin compositions with and without bioactive glass fillers have been investigated to see the influence of bioactive glass on physical properties of the resin and resulting green body. The effect of concentration of monomers, reactive diluent, light absorber (Sudan orange G dye), photoinitiator (PI), non-reactive diluent, and fillers (BAG) on rheology and photocuring behavior of the resin and tomography of the resulting 3D structures have been investigated. The BAG contents affect the rheology of resin and influence the rate of the polymerization reaction. The resin compositions with 55–60% BAG, 10% PEG-200 (diluent), 1% of PI and 0.015% of the dye were found to be suitable compositions for the stereolithographic fabrication. A higher percentage of PI caused over-curing, while a higher amount of dye decreased the cure depth of the resin. The micro-computed tomography (µ-CT) and scanning electron microscopic (SEM) images of the resulting green bodies display a relatively dense glass scaffold without any visible cracks and good interlayer connection and surface finishing. These properties play an important role in the mechanical behavior of 3D scaffolds. This study will be helpful to prepare high density glass/ceramic slurries and optimize their printing properties
Effect of angiotensin-converting enzyme inhibitor and angiotensin receptor blocker initiation on organ support-free days in patients hospitalized with COVID-19
IMPORTANCE Overactivation of the renin-angiotensin system (RAS) may contribute to poor clinical outcomes in patients with COVID-19.
Objective To determine whether angiotensin-converting enzyme (ACE) inhibitor or angiotensin receptor blocker (ARB) initiation improves outcomes in patients hospitalized for COVID-19.
DESIGN, SETTING, AND PARTICIPANTS In an ongoing, adaptive platform randomized clinical trial, 721 critically ill and 58 non–critically ill hospitalized adults were randomized to receive an RAS inhibitor or control between March 16, 2021, and February 25, 2022, at 69 sites in 7 countries (final follow-up on June 1, 2022).
INTERVENTIONS Patients were randomized to receive open-label initiation of an ACE inhibitor (n = 257), ARB (n = 248), ARB in combination with DMX-200 (a chemokine receptor-2 inhibitor; n = 10), or no RAS inhibitor (control; n = 264) for up to 10 days.
MAIN OUTCOMES AND MEASURES The primary outcome was organ support–free days, a composite of hospital survival and days alive without cardiovascular or respiratory organ support through 21 days. The primary analysis was a bayesian cumulative logistic model. Odds ratios (ORs) greater than 1 represent improved outcomes.
RESULTS On February 25, 2022, enrollment was discontinued due to safety concerns. Among 679 critically ill patients with available primary outcome data, the median age was 56 years and 239 participants (35.2%) were women. Median (IQR) organ support–free days among critically ill patients was 10 (–1 to 16) in the ACE inhibitor group (n = 231), 8 (–1 to 17) in the ARB group (n = 217), and 12 (0 to 17) in the control group (n = 231) (median adjusted odds ratios of 0.77 [95% bayesian credible interval, 0.58-1.06] for improvement for ACE inhibitor and 0.76 [95% credible interval, 0.56-1.05] for ARB compared with control). The posterior probabilities that ACE inhibitors and ARBs worsened organ support–free days compared with control were 94.9% and 95.4%, respectively. Hospital survival occurred in 166 of 231 critically ill participants (71.9%) in the ACE inhibitor group, 152 of 217 (70.0%) in the ARB group, and 182 of 231 (78.8%) in the control group (posterior probabilities that ACE inhibitor and ARB worsened hospital survival compared with control were 95.3% and 98.1%, respectively).
CONCLUSIONS AND RELEVANCE In this trial, among critically ill adults with COVID-19, initiation of an ACE inhibitor or ARB did not improve, and likely worsened, clinical outcomes.
TRIAL REGISTRATION ClinicalTrials.gov Identifier: NCT0273570
Rapid synthesis of thermally stable hydroxyapaptite
We have optimized the wet precipitation synthesis of hydroxyapaptite to obtain thermally stable powder in the short time span of 3 min. Exposure of the reaction mixture to 1000 W microwave for 3 min furnished hydroxyapatite, which was thermally stable at temperatures up to 1200 °C. Powders were analyzed for phase purity using X-ray crystallography; chemical composition was studied using Fourier transform infrared spectroscopy while particle morphology was analyzed using scanning electron microscopy
Recent concepts in biodegradable polymers for tissue engineering paradigms:a critical review
Tissue engineering and regenerative medicine are emerging as future approaches for the treatment of acute and chronic diseases. Numerous clinical conditions exist today and include congenital disorders, trauma, infection, inflammation, and cancer, in which hard and soft tissue damage, organ failure and loss are still not treated effectively. Researchers are constantly developing new biomaterials and tissue-engineered technologies to stimulate tissue regeneration. Various emerging approaches according to organ, tissue, disease and disorder are identified. Irrespective, engineered biomaterials are required to regenerate and ultimately reproduce the original physiological, biological, chemical, and mechanical properties. Biodegradable materials have been used extensively as regenerative therapies. The selection, design, biological and physicochemical properties of these materials are important and must be considered for stimulating tissue growth. In this review, we critique recently developed biodegradable materials for tissue regeneration of some targeted organs e.g., skin, nerves, blood vessels, heart, cornea, trachea, dental/oral structure and bones
Incidence and management of cleft lip and palate in Pakistan
OBJECTIVE: To compare the occurrence, distribution and management of clefts of lip and palate in local patients with the available data from India and China. METHODS: The retrospective study was conducted at the Interdisciplinary Research Centre in Biomedical Materials, COMSATS University Islamabad, Lahore Campus, Lahore, Pakistan, and comprised data related to a three-month period from January to March 2015 at two medical centres in Lahore. Data from Pakistani centres was analysed based on province, gender, age and clefts of lip and palate conditions and Spearman's correlation matrix. RESULTS: Of the 1574 cases, 1061(67.4%) were from Punjab, 361(23%) Khyber Pakhtunkhwa, 85(5%) Sindh and 67(4.2%) were from Azad Jammu and Kashmir. The incidence of clefts of lip and palate was higher in males than females. There was higher awareness of the need for timely management in new borns with clefts of lip and palate. Some patients seeking secondary treatment were also being surgically corrected. There is no national registry of children born with cleft defect, making it difficult to assess the full scale of the problem.. CONCLUSIONS: Based on available data, it is likely that there are many adults who have not been treated when younger.
Electrophoretic deposition of PVA coated hydroxyapatite on 316L stainless steel
Polyvinyl alcohol (PVA) coated hydroxyapatite was deposited onto a 316L stainless steel substrate by electrophoretic deposition. Deposition was carried out in a methanol suspension at pH 5.5 using a graphite rod as an anode. Parameters such as PVA concentration, deposition voltage and time were optimized to achieve a homogeneous, crack-free adhesive coating. Techniques such as X-ray diffraction and Fourier transform infrared spectroscopy were used to study the phase composition of the coated materials and the stability of hydroxyapatite in the presence of PVA
Bioresorbable antibacterial PCL-PLA-nHA composite membranes for oral and maxillofacial defects
Degradable implant membranes designed to separate hard and soft tissues and to trigger the growth of underlying bone and with antimicrobial properties are needed for the management of bone defects, ridge augmentation and to facilitate dental implants. In this study, the composite scaffolds of poly(lactic acid) (PLA), poly(caprolactone) (PCL) blended with nano hydroxyapatite and cefixime‐β cyclodextrin (Cfx‐βCD) inclusion complexes were synthesized by electrospinning. The prepared electrospun fibrous membranes were characterized by scanning electron microscopy and Fourier transform infrared (FTIR) spectroscopy. Membranes were microporous with random fibers in the range of 0.2–0.37 µm. The data from FTIR spectral analysis helped to characterize the presence of PCL, PLA, Cfx, and βCD in the electrospun membranes. In addition, the mechanical properties (i.e., elastic modulus and tensile strength) of the scaffolds were investigated. The mechanical strength and suture retention ability of the membranes was comparable to that of skin grafts. Drug release assays confirmed the slow release of Cfx from the membranes in the presence of βCD and antimicrobial studies showed that the membranes possessed antibacterial properties. The interaction of cells with membranes was evaluated by culturing them with the mouse pre‐osteoblast cell line MC3T3 and assessment of bone formation was done using Alizarin Red Assay. Culturing MC3T3 cells on the scaffolds showed that cells attached and entered the membranes and increased in number over time. In summary, these membranes are flexible, strong, bactericidal and osteogenic, which are the ideal implant properties for dental and maxillofacial surgery
Exploration of Ascochyta rabiei diversity through various molecular tools and control of its pathogenic strain via green synthesized zinc oxide nanoparticles
Fungus is the most important disease-causing biotic factor on earth. The study of their genetic diversity is very important for their management and control. For studying Ascochyta rabiei on chickpea blight chickpea samples caused by Ascochyta rabiei were collected and disease-causing organisms were isolated from infected plant parts and their ITS region was sequenced. BLAST analysis revealed that A. rabiei is the causal pathogen of this blight disease. Phylogenetic analysis suggested great diversity among these isolates of A. rabiei. The results confirm that A. rabiei strains collected from Bannu and Lakki Marwat have genetic similarities but are different from other isolated strains of the same species. Similarly, studied strains from Kamber, Shadat Kot, and Larkana. Khairpur and Bhakkar were also similar. However, strains from Khushab and Mianwali showed genetic differences from each other. The current research also reports the plant-mediated synthesis of ZnO NPs via the plant extract of Thevetia peruviana. The ZnO NPs were characterized through UV, XRD, FTIR, FE-SEM, EDX, and the size of the nanoparticle of 28 nm was calculated. The prepared nanoparticle was used for the antifungal activity against the most severe strain of A. rabiei. The Biosynthesis of ZnO NPs by plant assets is an eco-friendly, consistent process and appropriate for extensive production