Immobilization of Growth Factors to Collagen Surfaces Using Pulsed Visible Light.

In the treatment of traumatic injuries, burns, and ulcers of the eye, inadequate epithelial tissue healing remains a major challenge. Wound healing is a complex process involving the temporal and spatial interplay between cells and their extracellular milieu. It can be impaired by a variety of causes including infection, poor circulation, loss of critical cells, and/or proteins, and a deficiency in normal neural signaling (e.g., neurotrophic ulcers). Ocular anatomy is particularly vulnerable to lasting morbidity from delayed healing, whether it be scarring or perforation of the cornea, destruction of the conjunctival mucous membrane, or cicatricial changes to the eyelids and surrounding skin. Therefore, there is a major clinical need for new modalities for controlling and accelerating wound healing, particularly in the eye. Collagen matrices have long been explored as scaffolds to support cell growth as both two-dimensional coatings and substrates, as well as three-dimensional matrices. Meanwhile, the immobilization of growth factors to various substrates has also been extensively studied as a way to promote enhanced cellular adhesion and proliferation. Herein we present a new strategy for photochemically immobilizing growth factors to collagen using riboflavin as a photosensitizer and exposure to visible light (∼458 nm). Epidermal growth factor (EGF) was successfully bound to collagen-coated surfaces as well as directly to endogenous collagen from porcine corneas. The initial concentration of riboflavin and EGF as well as the blue light exposure time were keys to the successful binding of growth factors to these surfaces. The photocrosslinking reaction increased EGF residence time on collagen surfaces over 7 days. EGF activity was maintained after the photocrosslinking reaction with a short duration of pulsed blue light exposure. Bound EGF accelerated in vitro corneal epithelial cell proliferation and migration and maintained normal cell phenotype. Additionally, the treated surfaces were cytocompatible, and the photocrosslinking reaction was proven to be safe, preserving nearly 100% cell viability. These results suggest that this general approach is safe and versatile may be used for targeting and immobilizing bioactive factors onto collagen matrices in a variety of applications, including in the presence of live, seeded cells or in vivo onto endogenous extracellular matrix collagen.

High SARS-CoV-2 Seroprevalence among Healthcare Workers in Bamako, Mali.

In Mali, a country in West Africa, cumulative confirmed COVID-19 cases and deaths among healthcare workers (HCWs) remain enigmatically low, despite a series of waves, circulation of SARS-CoV-2 variants, the country's weak healthcare system, and a general lack of adherence to public health mitigation measures. The goal of the study was to determine whether exposure is important by assessing the seroprevalence of anti-SARS-CoV-2 IgG antibodies in HCWs. The study was conducted between November 2020 and June 2021. HCWs in the major hospitals where COVID-19 cases were being cared for in the capital city, Bamako, Mali, were recruited. During the study period, vaccinations were not yet available. The ELISA of the IgG against the spike protein was optimized and quantitatively measured. A total of 240 HCWs were enrolled in the study, of which seropositivity was observed in 147 cases (61.8%). A continuous increase in the seropositivity was observed, over time, during the study period, from 50% at the beginning to 70% at the end of the study. HCWs who provided direct care to COVID-19 patients and were potentially highly exposed did not have the highest seropositivity rate. Vulnerable HCWs with comorbidities such as obesity, diabetes, and asthma had even higher seropositivity rates at 77.8%, 75.0%, and 66.7%, respectively. Overall, HCWs had high SARS-CoV-2 seroprevalence, likely reflecting a "herd" immunity level, which could be protective at some degrees. These data suggest that the low number of cases and deaths among HCWs in Mali is not due to a lack of occupational exposure to the virus but rather related to other factors that need to be investigated.

Development and clinical evaluation of a new multiplex PCR assay for a simultaneous diagnosis of tuberculous and nontuberculous mycobacteria.

BACKGROUND: The prevalence of non-tuberculous mycobacteria (NTM) has been increasing worldwide in both developed and developing countries. NTM infection is clinically indistinguishable from tuberculosis and therefore poses significant challenges in patient management, especially in patients chronically treated for pulmonary TB. In this study, we evaluated a new highly sensitive Multiplex MTB/NTM assay that can differentiate M. tuberculosis complex (MTBC) from all NTM, including the treatable and most common NTM, M. avium complex (MAC). METHODS: We developed and optimized a new open- Multiplex MTB/NTM assay with two gene-targets for MTBC (IS6110/senX3-regX3) and two targets for MAC (IS1311/DT1) with samples spiked with stored strains and testing 20 replicates. Patients with presumptive TB and NTM were enrolled at the Respiratory Disease Department of The University Teaching Hospital of Point G, in Mali. FINDINGS: In the development stage, the new assay showed a high analytic performance with 100% detections of MTBC and MAC at only 5 colony forming units (CFUs). Overall, without the treatment failure cases, the Multiplex assay and the Xpert showed a sensitivity, specificity, PPV and NPV of 83·3% [66·4-92·6], 96·6% [88·6-99·0], 92·5% [82·3-96·5] and 92·2% [82·7-96·5] and the Xpert had values of 96·7% [83·3-99·4], 80·0% [68·2-88·1], 70·7 [55·5-82·3] and 97·9% [89·3-99·6], respectively. The Multiplex assay successfully detected all (5/5) the MAC cases. INTERPRETATION: Our new Multiplex assay demonstrates better specificity than Xpert for all group studied, in addition to detecting potential NTM cases. The assay could therefore complement the widely used Xpert assay and enhance discrimination of TB and NTM infections. FUNDING: This work was supported by the National Institutes of Health (R03AI137674, U54EB027049, D43TW010350 and UM1AI069471) and Northwestern University's Institute for Global Health Catalyzer Fund.

Repeatability and Reproducibility of Slit Lamp, Optical Coherence Tomography, and Scheimpflug Measurements of Corneal Scars.

Purpose: To determine the repeatability and reproducibility of anterior segment optical coherence tomography (AS-OCT) and Scheimpflug photography for several measurements of corneal scars, including scar size, scar depth, and corneal thickness. Methods: A series of patients treated for fungal keratitis at a tertiary eye care center in South India were recalled two years after successful treatment. Eyes with corneal scars had a slit lamp examination performed by two ophthalmologists masked to the other's examination. For AS-OCT and Scheimpflug photography, each eye had two scans taken by one technician and a third scan taken by a separate technician. Scar measurements were subsequently assessed from AS-OCT images by three graders masked to each other's results. Repeatability and reproducibility were assessed by calculating the intra-class correlation coefficient (ICC) from mixed effects linear regression models. Results: Fifty eyes had all measurements taken. The corneal scar size, measured as the geometric mean of the two longest perpendicular meridians, ranged from 0.8 to 5.4 (mean 2.8 mm, 95%CI 2.6 to 3.1). Scar size measurements taken by two separate individuals were most reproducible when the border of the scar was traced from the OCT (ICC 0.90, 95%CI 0.86 to 0.94), and least repeatable when assessed from slit lamp examination (ICC 0.80, 95%CI 0.70 to 0.90). Conclusions: AS-OCT and Scheimpflug imaging of corneal scars produced measurements with acceptable reproducibility that could be useful as cornea-specific outcomes for clinical trials.

Use of sodium dodecyl sulfate to improve tuberculosis sputum smear microscopy.

Sputum smear microscopy (SSM), the most widely available tool for tuberculosis (TB) detection, has limited performance in paucibacillary patients and requires highly experienced technicians. The objective of this study was to determine whether the addition of sodium dodecyl sulfate (SDS), a detergent that thins sputum, at 4% and 10%, improves the detection of acid-fast bacilli (AFB), the clarity of slides, and the biosafety of the technique. Thirty participants with presumptive TB were enrolled. Three independent, blinded technicians examined the slides. Regular sputum concentrated AFB smear and sputum culture were used as standard control methods. Sputum culture was also performed before and after 10% SDS addition for safety analysis. We found that neither SSM with SDS 4% nor SSM with SDS 10% improved the test's performance. However, slides with 4% and 10% SDS, compared with slides prepared without SDS, had significantly better clarity scores. The 10% SDS-prepared sputum samples were all culture negative. While adding SDS detergent does not improve the performance of SSM slides, it does improve the clarity and biosafety. Where experienced technicians are scarce, especially in low resource settings, use of SDS may enhance the ease of slide reading in sputum smear microscopy.

Simultaneous diagnosis of tuberculous and non-tuberculous mycobacterial diseases: Time for a better patient management.

Tuberculosis (TB) is the deadliest infectious disease in the world which disproportionately affects low-and-middle-income countries (LMICs) where diagnostic resources and treatment options are limited. The incidence of pulmonary non-tuberculous mycobacteria (NTM) disease is also rapidly increasing in these regions traditionally dominated by TB infections. This poses significant diagnostic and treatment challenges, since these two diseases are often indistinguishable clinically or by sputum smear microscopy (SSM), the most commonly used TB diagnostic tool in LMICs. Consequently, NTM-infected patients usually receive unnecessary TB treatment for months. TB patients with NTM co-infections may also be treated incorrectly due to inaccurate SSM and Xpert™ MTB/RIF (M. tuberculosis./rifampin) results. These issues complicate the management of patients and contribute to the worsening of the current TB and NTM epidemiological features including development of drug resistant strains. It is therefore critical to develop improved diagnostic tools to accurately distinguish these two different pathogens that have many similar clinical and epidemiological features but have different treatment regimens. In this review, we will discuss limitations with current diagnostic tools and the need to develop novel techniques that can accurately and simultaneously diagnose TB and NTM disease._.

Preventing lower extremity distal embolization using embolic filter protection: results of the PROTECT registry.

PURPOSE: To report the results from a single-center prospective registry (PROTECT) established to evaluate the safety and effectiveness of embolic filter protection (EFP) in reducing distal embolization during percutaneous lower extremity interventions. METHODS: Patients undergoing angioplasty, stenting, or SilverHawk atherectomy and adjunctive balloon angioplasty for infrainguinal occlusive disease were eligible if the lesion(s) met one or more of these angiographic criteria: (1) moderate or severe calcification of any length, (2) total occlusions of any length, (3) a filling defect, (4) irregular (ulcerated) lesions at least 30 mm in length, and/or (5) smooth, non-ulcerated lesions at least 50 mm in length. The primary angiographic outcome was the ability of the filter to prevent angiographically visible distal embolization, slow flow, and loss of distal tibial runoff with or without capturing macrodebris. RESULTS: Forty patients (23 men; mean age 71.4+/-11.5 years) with 56 lesions (42 de novo and 14 restenotic) underwent treatment with angioplasty/stenting (group A, n = 29; 43 lesions) or SilverHawk atherectomy (group B, n = 11; 13 lesions). One filter was used per patient (25 SpiderFX and 15 EmboShield). Macroembolization occurred in 22 (55.0%) patients, 11 (37.9%) in group A and 11 (100%) in group B (p<0.001). Clinically significant (> or =2 mm in diameter) macrodebris was found in 18 (45.0%) patients: 8 (27.6%) in group A and 10 (90.9%) in group B (p<0.001). All filters were retrieved successfully with no complications. One side-branch embolization occurred proximal to the filter. In another case, the filter was overfilled, resulting in no distal flow; it was retrieved, with subsequent tibial embolization when the procedure was continued without protection. CONCLUSION: Macroembolization is very frequent in patients undergoing lower extremity interventions, particularly with SilverHawk atherectomy. EFP appears to be very effective in capturing macrodebris, and its use is associated with good acute angiographic outcome. The clinical significance of these findings needs to be determined in future studies.

Utilization of GP IIb/IIIa inhibitors in peripheral percutaneous interventions: current applications and in-hospital outcomes at a tertiary referral center.

The pattern of use of glycoprotein (GP) IIb/IIIa receptor inhibitors in peripheral percutaneous interventions (PPI) remains unclear. Data on patients who received GP IIb/IIIa inhibitors during PPI were extracted from a prospective registry that tracks demographic, angiographic and in-hospital outcomes of patients at 2 medical centers. Primary success was defined as establishing thrombolysis in myocardial infarction (TIMI) 3 flow and < 30% residual in vessels treated. Primary safety endpoints included death, unplanned amputation, vascular access complications, major bleeding and thrombocytopenia. Patients were divided into planned versus bailout use of GP IIb/IIIa inhibitors. A total of 46 patients (128 vessels) were included in this study. The procedure was performed emergently, urgently and electively in 13%, 26.1% and 60.9% of patients, respectively. The mean age was 70.9 +/- 11.2 years and 52.2% of patients were males. The patients' Rutherford-Baker Classes III, IV and V-VI were observed in 32.6%, 32.6% and 34.8%, respectively. Patients had the following comorbidities: current smokers 37%, diabetics 35.8%, dyslipidemics 71.7% and hypertensives 78.3%. Angiographic thrombus was suspected in 45.7% of patients prior to and during the procedure. The primary success endpoint was met in 66.4% of vessels and 69.6% of patients. Primary safety endpoints were as follows: death 2.2%, vascular access complication 2.2%, major unplanned amputation 0%, major bleeding 0% and thrombocytopenia 2.2%. Treatment with GP IIb/IIIa inhibitors was planned in 13 (28.3%) patients and bailout in 33 patients (71.7%). Reasons for planned GP IIb/IIIa were the presence of angiographic thrombus in 7 (53.8%) patients, advanced limb ischemia (Rutherford-Baker IV-VI) with total occlusions in 5 (38.5%) patients and acute presentation with total occlusion in 1 (7.7%) patient. Reasons for bailout were slow-flow in 16 (48.5%) patients, thrombus with no slow-flow in 12 (36.4%) patients, poor runoff in 1 (3%) patient and preventative during the procedure in 4 (12%) patients. In patients who received planned GP IIb/IIIa treatment, slow-flow occurred in 1/13 (7.7%) and embolization in 0/13 (0%) patients. We conclude that GP IIb/IIIa inhibitors were used as adjunctive therapy prior to angioplasty in critical limb ischemia patients or thrombotic lesions or as bailout in patients experiencing slow-flow and thrombus during PPI. Planned GP IIb/IIIa inhibitors appear to have favorable outcomes with a low incidence of slow-flow and embolization, however, randomized data are needed before establishing the role of GP IIb/IIIa inhibitor use in high-risk PPI.