A biodegradable antibiotic-impregnated scaffold to prevent osteomyelitis in a contaminated in vivo bone defect model.

Open fractures are at risk of serious infection and, if infected, require several surgical interventions and courses of systemic antibiotics. We investigated a new injectable formulation that simultaneously hardens in vivo to form a porous scaffold for bone repair and delivers antibiotics at high concentrations to the local site of infection. Duration of antimicrobial activity against Staphylococcus aureus was determined using the serial plate transfer test. Ultimate compressive strength and porosity of the material was measured with and without antibiotics. The material was evaluated in vivo in an ovine medial femoral condyle defect model contaminated with S. aureus. Sheep were sacrificed at either 2 or 13 weeks and the defect and surrounding bone assessed using micro-computed tomography and histology. Antimicrobial activity in vitro persisted for 19-21 days. Sheep with antibiotic-free material and bacteria became infected, while those with antibiotic-containing material and bacteria did not. Similarly, new bone growth was seen in uninoculated animals with plain polymer, and in those with antibiotic polymer with bacteria, but not in sheep with plain polymer and bacteria. The antibiotic-impregnated scaffolds were effective in preventing S. aureus infections whilst supporting bone growth and repair. If translated into clinical practice, this approach might reduce the need for systemic antibiotics.

Intraoperative scrub nurse turnover in orthopaedic surgery procedures: An opportunity for improved operating room efficiency.

BACKGROUND: Scrub nurses play a crucial role in facilitating orthopaedic surgeries, and thus intraoperative scrub nurse turnover may disrupt the workflow of the surgical team and prolong duration of surgery (DOS). The purpose of this study was to quantify the impact of intraoperative scrub nurse turnover on operative time of orthopaedic surgeries lasting less than 3h in duration. METHODS: Prospectively collected databases from two institutions were retrospectively queried to identify all orthopaedic procedures of maximum mean duration of 180min from March 4th, 2018 to August 31st, 2022. Cases were divided into two groups, those with scrub nurse turnover and those without. Propensity score matching was conducted to match groups by surgeon, hospital, patient age, gender, and ASA classification. Unpaired t-tests were used to compare mean DOS for each surgical procedure. Average treatment effect on treated (ATET) with 95% confidence intervals (CIs) were calculated. RESULTS: Scrub nurse turnover significantly prolonged DOS for both bone forearm facture open reduction and internal fixation (ORIF) (ATET=21.08, p=0.001), ankle ORIF (ATET=21.26, p<0.001), clavicle ORIF (ATET=16.16, p=0.028), femur intramedullary nail (ATET=11.52, p=0.003), rotator cuff repair (ATET=16.88, p<0.001), partial discectomy (ATET=10.52, p=0.001), total knee arthroplasty (TKA) (ATET=5.69, p<0.001), anterior total hip arthroplasty (THA) (ATET=8.80, p<0.001), lateral THA (ATET=7.02, p<0.001), and uncemented hip hemiarthroplasty (ATET=16.79, p=0.049). CONCLUSION: Intraoperative scrub nurse turnover significantly prolongs surgical times in orthopaedic surgeries lasting up to 3h in duration. This highlights the importance of developing strategies to prevent intraoperative scrub nurse turnover to improve OR efficiency and decrease healthcare costs.

ELISA-based detection of fresh and frozen-thawed lamb meat: a promising analytical approach for meat authentication.

Fresh/chilled meat differs in quality from frozen-thawed meat, and consumers prefer fresh meat over frozen-thawed meat. Differentiating between the two types of meat is an important part of the meat quality control system. This study aimed to develop an ELISA based on cytoplasmic antioxidant enzyme superoxide dismutase (SOD) as a biomarker. IgGs were raised in experimental animals and purified using immunoaffinity chromatography. The assay was optimized with guinea pig anti-SOD pAb as the capture antibody and rabbit anti-SOD pAb as the detection antibody. The assay showed excellent performance for differentiation, as the ROC area under the curve values were >0.9. A sensitivity of 95.8% and specificity of 95.0% were observed at a positive percentage (PP%) criterion value of 52.752. Sandwich ELISA results showed a significant difference between the chilled and repeatedly frozen-thawed lamb samples. Lamb meat stored for five days in a chiller showed a PP% value below the threshold PP% value, indicating that the assay can differentiate meat until 5 days of chiller storage. In addition, a thawing time of more than 18 h at 4 ± 1 °C is required to differentiate between both types of lamb meat with a size of 500 g. The developed ELISA can be applied at various points in the meat value chain to differentiate fresh meat from frozen-thawed meat.

Development of superoxide dismutase based visual and spectrophotometric method for rapid differentiation of fresh and frozen-thawed buffalo meat.

Study aimed to develop biomarker-based assay for rapid detection of fresh and frozen-thawed buffalo meat in the supply chain. The method is based on development of a solvent system and identification of suitable substrate and developer for screening of biomarkers. For the confirmation column chromatography, gel electrophoresis and Western Blotting were carried out. Validation was done by intra- and inter-day validation, storability study, and determination of thermal history. Best results were shown with pH 8.0 Tris-HCl; extraction buffer, 205 µM nicotinamide adenine dinucleotide hydrogen; substrate, 184 µM Nitroblue tetrazolium, and 1.9 µM phenazine methosulfate; developer. The thermal history ranged from 0.14 to 0.17 during storage at -20 °C. The intra- and inter-day assay precision (CV %) ranged from 5.3 to 6.5 %; in chilled and 14.1 - 9.2 % in frozen-thawed samples. The study confirmed SOD as a viable biomarker. Developed method using SOD has significant potential for rapidly differentiating chilled or frozen-thawed meat.

Analysis of sintered polymer scaffolds using concomitant synchrotron computed tomography and in situ mechanical testing.

The mechanical behaviour of polymer scaffolds plays a vital role in their successful use in bone tissue engineering. The present study utilised novel sintered polymer scaffolds prepared using temperature-sensitive poly(DL-lactic acid-co-glycolic acid)/poly(ethylene glycol) particles. The microstructure of these scaffolds was monitored under compressive strain by image-guided failure assessment (IGFA), which combined synchrotron radiation computed tomography (SR CT) and in situ micro-compression. Three-dimensional CT data sets of scaffolds subjected to a strain rate of 0.01%/s illustrated particle movement within the scaffolds with no deformation or cracking. When compressed using a higher strain rate of 0.02%/s particle movement was more pronounced and cracks between sintered particles were observed. The results from this study demonstrate that IGFA based on simultaneous SR CT imaging and micro-compression testing is a useful tool for assessing structural and mechanical scaffold properties, leading to further insight into structure-function relationships in scaffolds for bone tissue engineering applications.

High procalcitonin and thrombocytopenic purpura in a case of Kikuchi-Fujimoto disease.

Kikuchi-Fujimoto disease is a mild and rare idiopathic disease, particularly in children. It is mostly characterized by painful cervical lymphadenopathy and/or prolonged fever and confirmed by histology. We report a case of Kikuchi-Fujimoto disease in a 14-year-old teenager with high procalcitonin concentration and thrombocytopenic purpura.

Arachidonic acid release and inositol lipid metabolism in response to bradykinin and related peptides in human endometrial cells in vitro.

Prostaglandins of the 2 series are known to play a role in the regulation of menstruation and implantation but, more recently, other vasoactive peptides have been considered as potential regulators of these endometrial processes. The aim of the present study was to investigate the action of the potent vasoactive peptide bradykinin and the structurally related peptide, kallidin, on endometrial function by examining their effect on phosphoinositide hydrolysis and arachidonic acid release from endometrial cells in vitro. Primary cultures of endometrial glands and stromal cells were prelabelled with [14C]-arachidonic acid (AA) or [3H]-inositol to monitor arachidonic acid release and inositol phosphate accumulation respectively. Bradykinin and kallidin stimulated a dose and time-dependent release of arachidonic acid from stromal cells which, with 100 nmol/L bradykinin, was 30-150% above basal release and maximal at 5 min. Glands were less responsive; 100 nmol/L bradykinin (at 5 min) caused a release of AA of 30-69% above basal level. Bradykinin also stimulated a dose dependent increase in inositol monophosphate production. The maximum response with stromal cells was 8- to 10-fold and with glands, 2-fold (1 and 100 nmol/L bradykinin, respectively). Kallidin was equipotent to bradykinin with respect to both AA and inositol phosphate accumulation. The bradykinin analogue des Arg bradykinin (which acts through the B1 receptor) released AA from stromal cells but did not alter phosphoinositide hydrolysis, suggesting that these two cellular responses are mediated by different receptors (B1 and B2 respectively).(ABSTRACT TRUNCATED AT 250 WORDS)

Surgical delivery of drug releasing poly(lactic-co-glycolic acid)/poly(ethylene glycol) paste with in vivo effects against glioblastoma.

INTRODUCTION: The median survival of patients with glioblastoma multiforme (astrocytoma grade 4) remains less than 18 months despite radical surgery, radiotherapy and systemic chemotherapy. Surgical implantation of chemotherapy eluting wafers into the resection cavity has been shown to improve length of survival but the current licensed therapy has several drawbacks. This paper investigates in vivo efficacy of a novel drug eluting paste in glioblastoma. METHODS: Poly(lactic-co-glycolic acid)/poly(ethylene glycol) (PLGA/PEG) self-sintering paste was loaded with the chemotherapeutic agent etoposide and delivered surgically into partially resected tumours in a flank murine glioblastoma xenograft model. RESULTS: Surgical delivery of the paste was successful and practical, with no toxicity or surgical morbidity to the animals. The paste was retained in the tumour cavity, and preliminary results suggest a useful antitumour and antiangiogenic effect, particularly at higher doses. Bioluminescent imaging was not affected significantly by the presence of the paste in the tumour. CONCLUSIONS: Chemotherapy loaded PLGA/PEG paste seems to be a promising technology capable of delivering active drugs into partially resected tumours. The preliminary results of this study suggest efficacy with no toxicity and will lead to larger scale efficacy studies in orthotopic glioblastoma models.