Background:
Clinical application of platelet-rich plasma (PRP) in the realm of orthopaedic sports medicine has yielded variable results. Differences in separation methods and variability of the ...individual may contribute to these variable results.
Purpose:
To compare the effects of different PRP separation methods on human bone, muscle, and tendon cells in an in vitro model.
Study Design:
Controlled laboratory study.
Methods:
Blood collected from 8 participants (mean ± SD age 31.6 ± 10.9 years) was used to obtain PRP preparations. Three different PRP separation methods were used: a single-spin process yielding a lower platelet concentration (PRPLP), a single-spin process yielding high platelet and white blood cell concentrations (PRPHP), and a double-spin that produces a higher platelet concentration and lower white blood cell concentration (PRPDS). Human bone, muscle, and tendon cells obtained from discarded tissue samples during shoulder surgery were placed into culture and treated with the 3 PRP preparations, control media (2% fetal bovine serum FBS and 10% FBS), and native blood. Radioactive thymidine assays were obtained to examine cell proliferation, and testing with enzyme-linked immunosorbent assay was used to determine growth factor concentrations.
Results:
Addition of PRPLP to osteocytes, myocytes, and tenocytes significantly increased cell proliferation (P ≤ .05) compared with the controls. Adding PRPDS to osteoblasts and tenocytes increased cell proliferation significantly (P ≤ .05), but no significance was shown for its addition to myocytes. The addition of PRPHP significantly increased cell proliferation compared with the controls only when added to tenocytes (P ≤ .05). Osteoblasts: Proliferation was significantly increased by addition of PRPLP compared with all controls (2% FBS, 10% FBS, native blood) (P ≤ .05). Addition of PRPDS led to significantly increased proliferation compared with all controls, native blood, and PRPHP (P ≤ .05). Proliferation was significantly less when PRPHP was added compared with PRPDS (P ≤ .05). Myocytes: Proliferation was significantly increased by addition of PRPLP compared with native blood (P ≤ .05). Adding PRPHP or PRPDS to myocytes showed no significant increase in proliferation compared with the controls or the other separations. Tenocytes: Proliferation was significantly increased by addition of PRPLP compared with all controls (2% FBS, 10% FBS, native blood) (P ≤ .05). Addition of PRPDS showed a significant increase compared with the controls and native blood. For tenocytes, there was a significant increase (P ≤ .05) seen when PRPHP was added compared with the controls and native blood but not compared with the other separations.
Conclusion:
The primary findings of this study suggest the application of different PRP separations may result in a potential beneficial effect on the clinically relevant target cells in vitro. However, it is unclear which platelet concentration or PRP preparation may be optimal for the treatment of various cell types. In addition, a “more is better” theory for the use of higher platelet concentrations cannot be supported. This study was not intended to prove efficacy but to provide a platform for future research to be built upon.
Clinical Relevance:
The utilization of different PRP separations may result in a potentially beneficial effect on the clinically relevant target cells in vitro, but it is unclear which platelet concentration or PRP preparation may be optimal for the treatment of various cell types.
The coronavirus disease 2019 (COVID-19) pandemic enforced changes to healthcare services at a pace and extent not seen previously in the NHS. The Royal Devon and Exeter provides regional vascular ...surgery services. A consultant-led urgent 'hot clinic' was established, providing patients with ambulatory care. We aim to describe the service for critical limb ischaemia (CLI) before and during the COVID-19 pandemic, and evaluate this against recommended best practice.
Retrospective review of electronic databases and records of patients with CLI during a non-COVID vs COVID-19 period. Primary outcome measures were those established by guidance from the Vascular Society of Great Britain and Ireland.
Non-COVID vs COVID-19: total patients
=97 vs 96, of which CLI patients
=29 vs 21. Median length of stay 15 vs 0 days (
<0.001); median time from referral to specialist review 0 vs 3 days (
<0.001); multidisciplinary team meeting (MDT) recorded 3% vs 29%; median time to intervention 6 vs 8 days; conservative management 52% vs 67%; endovascular 28% vs 10%; open surgery 21% vs 24%; 30-day survival 79% vs 76%.
COVID-19 imposed a major change to the service for patients with CLI with a focus on ambulatory care pathways for diagnosis and intervention. We observe a significant reduction in overall length of stay with no clinically significant change in time to consultant review, time to imaging, overall management strategy or outcomes. The results of this study show that patients with CLI can be managed safely and effectively on an ambulatory basis in accordance with established best practice.
Patient-derived xenograft (PDX) models have recently emerged as a highly desirable platform in oncology and are expected to substantially broaden the way
studies are designed and executed and to ...reshape drug discovery programs. However, acquisition of patient-derived samples, and propagation, annotation and distribution of PDXs are complex processes that require a high degree of coordination among clinic, surgery and laboratory personnel, and are fraught with challenges that are administrative, procedural and technical. Here, we examine in detail the major aspects of this complex process and relate our experience in establishing a PDX Core Laboratory within a large academic institution.
Climate change predictions derived from coupled carbon-climate models are highly dependent on assumptions about feedbacks between the biosphere and atmosphere. One critical feedback occurs if C ...uptake by the biosphere increases in response to the fossil-fuel driven increase in atmospheric CO2 ("CO2 fertilization"), thereby slowing the rate of increase in atmospheric CO2. Carbon exchanges between the terrestrial biosphere and atmosphere are often first represented in models as net primary productivity (NPP). However, the contribution of CO2 fertilization to the future global C cycle has been uncertain, especially in forest ecosystems that dominate global NPP, and models that include a feedback between terrestrial biosphere metabolism and atmospheric CO2 are poorly constrained by experimental evidence. We analyzed the response of NPP to elevated CO2 (approximately equal to 550 ppm) in four free-air CO2 enrichment experiments in forest stands. We show that the response of forest NPP to elevated CO2 is highly conserved across a broad range of productivity, with a stimulation at the median of 23 +/- 2%. At low leaf area indices, a large portion of the response was attributable to increased light absorption, but as leaf area indices increased, the response to elevated CO2 was wholly caused by increased light-use efficiency. The surprising consistency of response across diverse sites provides a benchmark to evaluate predictions of ecosystem and global models and allows us now to focus on unresolved questions about carbon partitioning and retention, and spatial variation in NPP response caused by availability of other growth limiting resources.
Results are presented from a study of the distribution of heavy metals in street dusts of two cities in Midland England. The first (Birmingham) is a large urban area (population of 2.3 million), the ...second, Coventry, a small one (population of 0.3 million). Several trends were identified from Birmingham: higher concentrations were located near industrial areas in the northwest of the city and within the ring road. However, lower concentrations were found to the southwest in areas of mainly residential properties and parks. High values were also identified in association with junctions controlled by traffic lights where vehicles were likely to stop regularly. This last trend was further investigated in Coventry, where it was found that concentrations of heavy metals at junctions controlled by traffic signals and by pedestrian-controlled pelican lights (Mounted Pelican Controller, MPCs) were lower than those found in Birmingham, apart from Ni.
Antibody titers that inhibit the influenza virus hemagglutinin (HA) from engaging its receptor are the accepted correlate of protection from infection. Many potent antibodies with broad, ...intra-subtype specificity bind HA at the receptor binding site (RBS). One barrier to broad H1-H3 cross-subtype neutralization is an insertion (133a) between positions 133 and 134 on the rim of the H1 HA RBS. We describe here a class of antibodies that overcomes this barrier. These genetically unrestricted antibodies are abundant in the human B cell memory compartment. Analysis of the affinities of selected members of this class for historical H1 and H3 isolates suggest that they were elicited by H3 exposure and broadened or diverted by later exposure(s) to H1 HA. RBS mutations in egg-adapted vaccine strains cause the new H1 specificity of these antibodies to depend on the egg adaptation. The results suggest that suitable immunogens might elicit 133a-independent, H1-H3 cross neutralization by RBS-directed antibodies.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Background:
Platelet-rich plasma (PRP) has anti-inflammatory effects with potential applications in the treatment of osteoarthritis (OA).
Purpose:
To use an in vitro coculture model of OA in human ...cartilage and synovium to investigate the anti-inflammatory effects of 2 different PRP preparations.
Study Design:
Controlled laboratory study.
Methods:
A coculture system was created using osteoarthritic cartilage and synovium from 9 patients undergoing total knee arthroplasty. Interleukin-1β (IL-1β) was added to each coculture to induce inflammation. Two PRP preparations were obtained—one yielding low white blood cell and platelet concentrations (PRPLP) and one yielding high platelet and white blood cell concentrations (PRPHP). Either PRPLP, PRPHP, or medium was added to the coculture wells. Control wells contained OA cartilage and synovium but neither IL-1β nor PRP. Normal, non-OA cartilage was obtained to establish baseline gene expression levels. Quantitative polymerase chain reaction was used to measure changes in markers of inflammation in the tissues (a disintegrin and metalloproteinase with thrombospondin motifs–5 ADAMTS-5, tissue inhibitor of metalloproteinases–1 TIMP-1, vascular endothelial growth factor VEGF, aggrecan, and type I collagen) at 0, 24, 48, and 72 hours.
Results:
Treatment with PRPLP or PRPHP significantly decreased expression of TIMP-1 and ADAMTS-5 in cartilage, increased aggrecan expression in cartilage, and decreased ADAMTS-5, VEGF, and TIMP-1 expression in synovium compared with control cocultures (P < .05). There was significantly less nitric oxide production in the PRPLP and PRPHP groups compared with controls (P < .05). There were significant differences in gene expression in the normal cartilage compared with all 4 groups of OA cartilage at all 4 time points. Treatment with either PRPLP or PRPHP returned some gene expression to the same levels in normal cartilage but not for all markers of inflammation.
Conclusion:
This coculture model assessed 2 different PRP preparations and their anti-inflammatory effects over time on human OA cartilage and synovium. Both had a significant anti-inflammatory effect on gene expression; however, there was no difference in the anti-inflammatory effect between the 2 preparations.
Clinical Relevance:
Osteoarthritis is a leading cause of chronic disability, and less invasive treatment methods are needed. Study results suggest that PRP injections may be an effective alternative anti-inflammatory agent in the treatment of OA.
The widespread distribution of lentiviruses among African primates, and the lack of severe pathogenesis in many of these natural reservoirs, are taken as evidence for long-term co-evolution between ...the simian immunodeficiency viruses (SIVs) and their primate hosts. Evidence for positive selection acting on antiviral restriction factors is consistent with virus-host interactions spanning millions of years of primate evolution. However, many restriction mechanisms are not virus-specific, and selection cannot be unambiguously attributed to any one type of virus. We hypothesized that the restriction factor TRIM5, because of its unique specificity for retrovirus capsids, should accumulate adaptive changes in a virus-specific fashion, and therefore, that phylogenetic reconstruction of TRIM5 evolution in African primates should reveal selection by lentiviruses closely related to modern SIVs. We analyzed complete TRIM5 coding sequences of 22 Old World primates and identified a tightly-spaced cluster of branch-specific adaptions appearing in the Cercopithecinae lineage after divergence from the Colobinae around 16 million years ago. Functional assays of both extant TRIM5 orthologs and reconstructed ancestral TRIM5 proteins revealed that this cluster of adaptations in TRIM5 specifically resulted in the ability to restrict Cercopithecine lentiviruses, but had no effect (positive or negative) on restriction of other retroviruses, including lentiviruses of non-Cercopithecine primates. The correlation between lineage-specific adaptations and ability to restrict viruses endemic to the same hosts supports the hypothesis that lentiviruses closely related to modern SIVs were present in Africa and infecting the ancestors of Cercopithecine primates as far back as 16 million years ago, and provides insight into the evolution of TRIM5 specificity.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
PDF
