DOE Office of Scientific and Technical Information (OSTI.GOV)

K Kucera; A Koblansky; L Saunders

Profilins promote actin polymerization by exchanging ADP for ATP on monomeric actin and delivering ATP-actin to growing filament barbed ends. Apicomplexan protozoa such as Toxoplasma gondii invade host cells using an actin-dependent gliding motility. Toll-like receptor (TLR) 11 generates an innate immune response upon sensing T. gondii profilin (TgPRF). The crystal structure of TgPRF reveals a parasite-specific surface motif consisting of an acidic loop, followed by a long {beta}-hairpin. A series of structure-based profilin mutants show that TLR11 recognition of the acidic loop is responsible for most of the interleukin (IL)-12 secretion response to TgPRF in peritoneal macrophages. Deletion ofmore » both the acidic loop and the {beta}-hairpin completely abrogates IL-12 secretion. Insertion of the T. gondii acidic loop and {beta}-hairpin into yeast profilin is sufficient to generate TLR11-dependent signaling. Substitution of the acidic loop in TgPRF with the homologous loop from the apicomplexan parasite Cryptosporidium parvum does not affect TLR11-dependent IL-12 secretion, while substitution with the acidic loop from Plasmodium falciparum results in reduced but significant IL-12 secretion. We conclude that the parasite-specific motif in TgPRF is the key molecular pattern recognized by TLR11. Unlike other profilins, TgPRF slows nucleotide exchange on monomeric rabbit actin and binds rabbit actin weakly. The putative TgPRF actin-binding surface includes the {beta}-hairpin and diverges widely from the actin-binding surfaces of vertebrate profilins.« less

A self-reference PRF-shift MR thermometry method utilizing the phase gradient

NASA Astrophysics Data System (ADS)

Langley, Jason; Potter, William; Phipps, Corey; Huang, Feng; Zhao, Qun

2011-12-01

In magnetic resonance (MR) imaging, the most widely used and accurate method for measuring temperature is based on the shift in proton resonance frequency (PRF). However, inter-scan motion and bulk magnetic field shifts can lead to inaccurate temperature measurements in the PRF-shift MR thermometry method. The self-reference PRF-shift MR thermometry method was introduced to overcome such problems by deriving a reference image from the heated or treated image, and approximates the reference phase map with low-order polynomial functions. In this note, a new approach is presented to calculate the baseline phase map in self-reference PRF-shift MR thermometry. The proposed method utilizes the phase gradient to remove the phase unwrapping step inherent to other self-reference PRF-shift MR thermometry methods. The performance of the proposed method was evaluated using numerical simulations with temperature distributions following a two-dimensional Gaussian function as well as phantom and in vivo experimental data sets. The results from both the numerical simulations and experimental data show that the proposed method is a promising technique for measuring temperature.

Comparison of the Regenerative Effects of Platelet-Rich Fibrin and Plasma Rich in Growth Factors on Injured Peripheral Nerve: An Experimental Study.

PubMed

Torul, Damla; Bereket, Mehmet Cihan; Onger, Mehmet Emin; Altun, Gamze

2018-04-20

The aim of this study was to investigate the effects of platelet-rich fibrin (PRF) and plasma rich in growth factors (PRGF) on peripheral nerve injury in the early period of healing. Thirty Wistar albino rats were used in this study. Rats were divided into control (C), damaged (D), PRF, and PRGF groups. The left sciatic nerves of each group were identified as group C. Crush-type injury was performed on the right sciatic nerves of the D, PRF, and PRGF groups. In the PRF and PRGF groups, blood 2 mL was obtained to prepare the PRF and PRGF and the biomaterials were applied to the injured nerve area. After 8 weeks, functional, electrophysiologic, and stereological evaluations were performed. For the electrophysiologic evaluation, the latency and amplitude values in the D, PRF, and PRGF groups were significantly lower than those in the C group (P > .05). According to the sciatic functional index result, there were significant differences between groups D and PRF and between groups D and PRGF (P = .000). For the stereological evaluations, although no significant difference was observed between the PRGF and C groups (P > .05), a significant difference was observed among the D, PRF, and PRGF groups for myelinated axon number. There were significant differences between groups D and PRF and between groups D and PRGF for axon area (P = .021 and .001, respectively). No significant difference was observed among the D, PRF, and PRGF groups for myelin sheath thickness and ratio of axon area to myelin sheath thickness (P > .05). The results of this study suggest that PRGF increases nerve regeneration in the early period of healing and that the limited early action of PRF should be re-evaluated in the late period. Copyright © 2018 American Association of Oral and Maxillofacial Surgeons. Published by Elsevier Inc. All rights reserved.

Effect of Platelet-Rich Fibrin on Peripheral Nerve Regeneration.

PubMed

Şenses, Fatma; Önder, Mustafa E; Koçyiğit, Ismail D; Kul, Oğuz; Aydin, Gülümser; Inal, Elem; Atil, Fethi; Tekin, Umut

2016-10-01

This study aimed to evaluate the effect of platelet-rich fibrin (PRF) on peripheral nerve regeneration on the sciatic nerve of rats by using functional, histopathologic, and electrophysiologic analyses. Thirty female Wistar rats were divided randomly into 3 experimental groups. In group 1 (G1), which was the control group, the sciatic nerve was transected and sutured (n = 10). In group 2 (G2), the sciatic nerve was transected, sutured, and then covered with PRF as a membrane (n = 10). In group 3 (G3), the sciatic nerve was transected, sutured by leaving a 5-mm gap, and then covered by PRF as a nerve guide (n = 10). Functional, histopathologic, and electrophysiologic analyses were performed. The total histopathologic semiquantitative score was significantly higher in G1 compared to G2 and G3 (P < 0.05). Myelin thickness and capillaries were significantly lower in G3 compared to G1 (P < 0.05). There was no statistically significant difference between the groups with regard to the functional and electrophysiologic results. The study results suggest that PRF decreases functional recovery in sciatic nerve injury. Further studies are required to determine the efficacy of PRF on peripheral nerve regeneration.

Growth factor and pro-inflammatory cytokine contents in platelet-rich plasma (PRP), plasma rich in growth factors (PRGF), advanced platelet-rich fibrin (A-PRF), and concentrated growth factors (CGF).

PubMed

Masuki, Hideo; Okudera, Toshimitsu; Watanebe, Taisuke; Suzuki, Masashi; Nishiyama, Kazuhiko; Okudera, Hajime; Nakata, Koh; Uematsu, Kohya; Su, Chen-Yao; Kawase, Tomoyuki

2016-12-01

The development of platelet-rich fibrin (PRF) drastically simplified the preparation procedure of platelet-concentrated biomaterials, such as platelet-rich plasma (PRP), and facilitated their clinical application. PRF's clinical effectiveness has often been demonstrated in pre-clinical and clinical studies; however, it is still controversial whether growth factors are significantly concentrated in PRF preparations to facilitate wound healing and tissue regeneration. To address this matter, we performed a comparative study of growth factor contents in PRP and its derivatives, such as advanced PRF (A-PRF) and concentrated growth factors (CGF). PRP and its derivatives were prepared from the same peripheral blood samples collected from healthy donors. A-PRF and CGF preparations were homogenized and centrifuged to produce extracts. Platelet and white blood cell counts in A-PRF and CGF preparations were determined by subtracting those counts in red blood cell fractions, supernatant acellular serum fractions, and A-PRF/CGF exudate fractions from those counts of whole blood samples. Concentrations of growth factors (TGF-β1, PDGF-BB, VEGF) and pro-inflammatory cytokines (IL-1β, IL-6) were determined using ELISA kits. Compared to PRP preparations, both A-PRF and CGF extracts contained compatible or higher levels of platelets and platelet-derived growth factors. In a cell proliferation assay, both A-PRF and CGF extracts significantly stimulated the proliferation of human periosteal cells without significant reduction at higher doses. These data clearly demonstrate that both A-PRF and CGF preparations contain significant amounts of growth factors capable of stimulating periosteal cell proliferation, suggesting that A-PRF and CGF preparations function not only as a scaffolding material but also as a reservoir to deliver certain growth factors at the site of application.

Cortical depth dependent population receptive field attraction by spatial attention in human V1.

PubMed

Klein, Barrie P; Fracasso, Alessio; van Dijk, Jelle A; Paffen, Chris L E; Te Pas, Susan F; Dumoulin, Serge O

2018-04-27

Visual spatial attention concentrates neural resources at the attended location. Recently, we demonstrated that voluntary spatial attention attracts population receptive fields (pRFs) toward its location throughout the visual hierarchy. Theoretically, both a feed forward or feedback mechanism could underlie pRF attraction in a given cortical area. Here, we use sub-millimeter ultra-high field functional MRI to measure pRF attraction across cortical depth and assess the contribution of feed forward and feedback signals to pRF attraction. In line with previous findings, we find consistent attraction of pRFs with voluntary spatial attention in V1. When assessed as a function of cortical depth, we find pRF attraction in every cortical portion (deep, center and superficial), although the attraction is strongest in deep cortical portions (near the gray-white matter boundary). Following the organization of feed forward and feedback processing across V1, we speculate that a mixture of feed forward and feedback processing underlies pRF attraction in V1. Specifically, we propose that feedback processing contributes to the pRF attraction in deep cortical portions. Copyright © 2018. Published by Elsevier Inc.

Activating receptors promote NK cell expansion for maintenance, IL-10 production, and CD8 T cell regulation during viral infection.

PubMed

Lee, Seung-Hwan; Kim, Kwang-Sin; Fodil-Cornu, Nassima; Vidal, Silvia M; Biron, Christine A

2009-09-28

Natural killer (NK) cells have the potential to deliver both direct antimicrobial effects and regulate adaptive immune responses, but NK cell yields have been reported to vary greatly during different viral infections. Activating receptors, including the Ly49H molecule recognizing mouse cytomegalovirus (MCMV), can stimulate NK cell expansion. To define Ly49H's role in supporting NK cell proliferation and maintenance under conditions of uncontrolled viral infection, experiments were performed in Ly49h(-/-), perforin 1 (Prf1)(-/-), and wild-type (wt) B6 mice. NK cell numbers were similar in uninfected mice, but relative to responses in MCMV-infected wt mice, NK cell yields declined in the absence of Ly49h and increased in the absence of Prf1, with high rates of proliferation and Ly49H expression on nearly all cells. The expansion was abolished in mice deficient for both Ly49h and Prf1 (Ly49h(-/-)Prf1(-/-)), and negative consequences for survival were revealed. The Ly49H-dependent protection mechanism delivered in the absence of Prf1 was a result of interleukin 10 production, by the sustained NK cells, to regulate the magnitude of CD8 T cell responses. Thus, the studies demonstrate a previously unappreciated critical role for activating receptors in keeping NK cells present during viral infection to regulate adaptive immune responses.

Pulsed radiofrequency treatment of articular branches of femoral and obturator nerves for chronic hip pain.

PubMed

Chye, Cien-Leong; Liang, Cheng-Loong; Lu, Kang; Chen, Ya-Wen; Liliang, Po-Chou

2015-01-01

Chronic hip pain is a common symptom experienced by many people. Often, surgery is not an option for patients with multiple comorbidities, and conventional drugs either have many side effects or are ineffective. Pulsed radiofrequency (PRF) is a new method in the treatment of pain. We attempt to compare the efficacy of PRF relative to conservative management for chronic hip pain. Between August 2011 and July 2013, 29 patients with chronic hip pain were divided into two groups (PRF and conservative treatment) according to consent or refusal to undergo PRF procedure. Fifteen patients received PRF of the articular branches of the femoral and obturator nerves, and 14 patients received conservative treatment. Visual analog scale (VAS), Oxford hip scores (OHS), and pain medications were used for outcome measurement before treatment and at 1 week, 4 weeks, and 12 weeks after treatment. At 1 week, 4 weeks, and 12 weeks after treatment initiation, improvements in VAS were significantly greater with PRF. Improvements in OHS were significantly greater in the PRF group at 1 week, 4 weeks, and 12 weeks. Patients in the PRF group also used less pain medications. Eight subjects in the conservative treatment group switched to the PRF group after 12 weeks, and six of them had >50% improvement. When compared with conservative treatment, PRF of the articular branches of the femoral and obturator nerves offers greater pain relief for chronic hip pain and can augment physical functioning.

A second-order orientation-contrast stimulus for population-receptive-field-based retinotopic mapping.

PubMed

Yildirim, Funda; Carvalho, Joana; Cornelissen, Frans W

2018-01-01

Visual field or retinotopic mapping is one of the most frequently used paradigms in fMRI. It uses activity evoked by position-varying high luminance contrast visual patterns presented throughout the visual field for determining the spatial organization of cortical visual areas. While the advantage of using high luminance contrast is that it tends to drive a wide range of neural populations - thus resulting in high signal-to-noise BOLD responses - this may also be a limitation, especially for approaches that attempt to squeeze more information out of the BOLD response, such as population receptive field (pRF) mapping. In that case, more selective stimulation of a subset of neurons - despite reduced signals - could result in better characterization of pRF properties. Here, we used a second-order stimulus based on local differences in orientation texture - to which we refer as orientation contrast - to perform retinotopic mapping. Participants in our experiment viewed arrays of Gabor patches composed of a foreground (a bar) and a background. These could only be distinguished on the basis of a difference in patch orientation. In our analyses, we compare the pRF properties obtained using this new orientation contrast-based retinotopy (OCR) to those obtained using classic luminance contrast-based retinotopy (LCR). Specifically, in higher order cortical visual areas such as LO, our novel approach resulted in non-trivial reductions in estimated population receptive field size of around 30%. A set of control experiments confirms that the most plausible cause for this reduction is that OCR mainly drives neurons sensitive to orientation contrast. We discuss how OCR - by limiting receptive field scatter and reducing BOLD displacement - may result in more accurate pRF localization as well. Estimation of neuronal properties is crucial for interpreting cortical function. Therefore, we conclude that using our approach, it is possible to selectively target particular neuronal populations, opening the way to use pRF modeling to dissect the response properties of more clearly-defined neuronal populations in different visual areas. Copyright © 2017 Elsevier Inc. All rights reserved.

High Voltage Pulsed Radiofrequency for the Treatment of Refractory Neuralgia of the Infraorbital Nerve: A Prospective Double-Blinded Randomized Controlled Study.

PubMed

Luo, Fang; Wang, Tao; Shen, Ying; Meng, Lan; Lu, Jingjing; Ji, Nan

2017-05-01

A recent study showed that 50% of patients who suffered from refractory neuralgia of the infraorbital nerve obtained satisfactory efficacy after pulsed radiofrequency (PRF) treatment. A pilot study showed that increasing the output voltage of PRF significantly improved the efficacy for trigeminal neuralgia; however, whether increasing the output voltage of PRF can improve the treatment outcomes for neuralgia of the infraorbital nerve is unknown. To evaluate the efficacy and safety of high voltage PRF treatment in comparison with standard voltage PRF for neuralgia of the infraorbital nerve. Prospective, single-center, double-blinded, randomized, controlled trial. Beijing Tiantan Hospital, Capital Medical University. A total of 60 patients with refractory neuralgia of the infraorbital nerve were randomly divided into the high voltage PRF group and the standard voltage PRF group to treat their infraorbital nerves. Neither the patients, pain physicians, nor the follow-up evaluators knew the patient group assignments. The primary outcome measure was the one-year response rate. The secondary outcome measures included the time to take effect after PRF, the one-month, 3-month, and 6-month response rates, the relapse rate, and adverse reactions. The intent-to-treat analysis showed that the one-month, 3-month, 6-month, and one-year response rates were all 90% in the high voltage group, which were significantly higher than the rates in the standard voltage group (67% [P < 0.05], 67% [P < 0.05], 63% [P < 0.05], and 60% [P <0.01], respectively). Furthermore, 27% of the patients in the high-voltage group and 13% of the patients in the standard voltage group experienced minor transient (10 - 30 days) numbness in the innervation area after PRF; no other serious adverse reactions were observed in the 2 groups (P > 0.05). We did not investigate the dose-effect relationship between the output voltage and efficacy or the effect of a higher pulse dose on efficacy. This study was a single-center study, and multi-center, randomized, controlled studies are needed to obtain the highest level of empirical evidence. Additionally, the follow-up period lasted only one year in this study; thus, long-term efficacy needs to be further confirmed. The results showed that high voltage PRF was effective and safe for patients with refractory neuralgia of the infraorbital nerve and could become a treatment option in patients who do not respond to conservative treatment.

Bayesian population receptive field modelling.

PubMed

Zeidman, Peter; Silson, Edward Harry; Schwarzkopf, Dietrich Samuel; Baker, Chris Ian; Penny, Will

2017-09-08

We introduce a probabilistic (Bayesian) framework and associated software toolbox for mapping population receptive fields (pRFs) based on fMRI data. This generic approach is intended to work with stimuli of any dimension and is demonstrated and validated in the context of 2D retinotopic mapping. The framework enables the experimenter to specify generative (encoding) models of fMRI timeseries, in which experimental stimuli enter a pRF model of neural activity, which in turns drives a nonlinear model of neurovascular coupling and Blood Oxygenation Level Dependent (BOLD) response. The neuronal and haemodynamic parameters are estimated together on a voxel-by-voxel or region-of-interest basis using a Bayesian estimation algorithm (variational Laplace). This offers several novel contributions to receptive field modelling. The variance/covariance of parameters are estimated, enabling receptive fields to be plotted while properly representing uncertainty about pRF size and location. Variability in the haemodynamic response across the brain is accounted for. Furthermore, the framework introduces formal hypothesis testing to pRF analysis, enabling competing models to be evaluated based on their log model evidence (approximated by the variational free energy), which represents the optimal tradeoff between accuracy and complexity. Using simulations and empirical data, we found that parameters typically used to represent pRF size and neuronal scaling are strongly correlated, which is taken into account by the Bayesian methods we describe when making inferences. We used the framework to compare the evidence for six variants of pRF model using 7 T functional MRI data and we found a circular Difference of Gaussians (DoG) model to be the best explanation for our data overall. We hope this framework will prove useful for mapping stimulus spaces with any number of dimensions onto the anatomy of the brain. Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.

Structure-Based Design of Inhibitors Targeting PrfA, the Master Virulence Regulator of Listeria monocytogenes.

PubMed

Kulén, Martina; Lindgren, Marie; Hansen, Sabine; Cairns, Andrew G; Grundström, Christin; Begum, Afshan; van der Lingen, Ingeborg; Brännström, Kristoffer; Hall, Michael; Sauer, Uwe H; Johansson, Jörgen; Sauer-Eriksson, A Elisabeth; Almqvist, Fredrik

2018-05-10

Listeria monocytogenes is a bacterial pathogen that controls much of its virulence through the transcriptional regulator PrfA. In this study, we describe structure-guided design and synthesis of a set of PrfA inhibitors based on ring-fused 2-pyridone heterocycles. Our most effective compound decreased virulence factor expression, reduced bacterial uptake into eukaryotic cells, and improved survival of chicken embryos infected with L. monocytogenes compared to previously identified compounds. Crystal structures identified an intraprotein "tunnel" as the main inhibitor binding site (A I ), where the compounds participate in an extensive hydrophobic network that restricts the protein's ability to form functional DNA-binding helix-turn-helix (HTH) motifs. Our studies also revealed a hitherto unsuspected structural plasticity of the HTH motif. In conclusion, we have designed 2-pyridone analogues that function as site-A I selective PrfA inhibitors with potent antivirulence properties.

Population receptive field (pRF) measurements of chromatic responses in human visual cortex using fMRI.

PubMed

Welbourne, Lauren E; Morland, Antony B; Wade, Alex R

2018-02-15

The spatial sensitivity of the human visual system depends on stimulus color: achromatic gratings can be resolved at relatively high spatial frequencies while sensitivity to isoluminant color contrast tends to be more low-pass. Models of early spatial vision often assume that the receptive field size of pattern-sensitive neurons is correlated with their spatial frequency sensitivity - larger receptive fields are typically associated with lower optimal spatial frequency. A strong prediction of this model is that neurons coding isoluminant chromatic patterns should have, on average, a larger receptive field size than neurons sensitive to achromatic patterns. Here, we test this assumption using functional magnetic resonance imaging (fMRI). We show that while spatial frequency sensitivity depends on chromaticity in the manner predicted by behavioral measurements, population receptive field (pRF) size measurements show no such dependency. At any given eccentricity, the mean pRF size for neuronal populations driven by luminance, opponent red/green and S-cone isolating contrast, are identical. Changes in pRF size (for example, an increase with eccentricity and visual area hierarchy) are also identical across the three chromatic conditions. These results suggest that fMRI measurements of receptive field size and spatial resolution can be decoupled under some circumstances - potentially reflecting a fundamental dissociation between these parameters at the level of neuronal populations. Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.

Platelet-rich concentrates differentially release growth factors and induce cell migration in vitro.

PubMed

Schär, Michael O; Diaz-Romero, Jose; Kohl, Sandro; Zumstein, Matthias A; Nesic, Dobrila

2015-05-01

Platelet-rich concentrates are used as a source of growth factors to improve the healing process. The diverse preparation protocols and the gaps in knowledge of their biological properties complicate the interpretation of clinical results. In this study we aimed to (1) analyze the concentration and kinetics of growth factors released from leukocyte- and platelet-rich fibrin (L-PRF), leukocyte- and platelet-rich plasma (L-PRP), and natural blood clot during in vitro culture; (2) investigate the migration of mesenchymal stem cells (MSCs) and human umbilical vein endothelial cells (HUVECs) as a functional response to the factors released; and (3) uncover correlations between individual growth factors with the initial platelet/leukocyte counts or the induced cell migration. L-PRF, L-PRP, and natural blood clot prepared from 11 donors were cultured in vitro for 28 days and media supernatants collected after 8 hours and 1, 3, 7, 14, and 28 days. Released transforming growth factor β1 (TGF-β1), vascular endothelial growth factor (VEGF), insulin growth factor (IGF-1), platelet-derived growth factor AB (PDGF-AB), and interleukin-1β (IL-1β) were measured in the supernatants with enzyme-linked immunosorbent assay. Migration of MSC and HUVEC induced by the supernatants was evaluated in Boyden chambers. More TGF-ß1 was released (mean ± SD in pg/mL of blood) from L-PRF (37,796 ± 5492) compared with L-PRP (23,738 ± 6848; p < 0.001) and blood clot (3739 ± 4690; p < 0.001), whereas more VEGF and IL-1ß were released from blood clot (1933 ± 704 and 2053 ± 908, respectively) compared with both L-PRP (642 ± 208; p < 0.001 and 273 ± 386; p < 0.001, respectively) and L-PRF (852 ± 376; p < 0.001 and 65 ± 56, p < 0.001, respectively). No differences were observed in IGF-1 and PDGF-AB released from any of the concentrates. TGF-β1 release peaked at Day 7 in L-PRF and at 8 hours and Day 7 in L-PRP and 8 hours and Day 14 in blood clot. In all concentrates, main release of VEGF occurred between 3 and 7 days and of IL-1β between Days 1 and 7. IGF-1 and PDGF-AB were released until Day 1 in L-PRP and blood clot, in contrast to sustained release over the first 3 days in L-PRF. The strongest migration of MSC occurred in response to L-PRF, and more HUVEC migration was seen in L-PRF and blood clot compared with L-PRP. TGF-β1 correlated with initial platelet counts in L-PRF (Pearson r = 0.66, p = 0.0273) and initial leukocyte counts in L-PRP (Pearson r = 0.83, p = 0.0016). A positive correlation of IL-1β on migration of MSC and HUVEC was revealed (Pearson r = 0.16, p = 0.0208; Pearson r = 0.31, p < 0.001). In comparison to L-PRP, L-PRF had higher amounts of released TGF-β1, a long-term release of growth factors, and stronger induction of cell migration. Future preclinical studies should confirm these data in a defined injury model. By characterizing the biologic properties of different platelet concentrates in vitro, we may gain a better understanding of their clinical effects and develop guidelines for specific future applications.

Bipolar High-Voltage, Long-Duration Pulsed Radiofrequency Improves Pain Relief in Postherpetic Neuralgia.

PubMed

Wan, Cheng-Fu; Liu, Yan; Dong, Dao-Song; Zhao, Lin; Xi, Qi; Yu, Xue; Cui, Wen-Yao; Wang, Qiu-Shi; Song, Tao

2016-07-01

Postherpetic neuralgia (PHN) is often refractory to existing treatments. Treatment of the dorsal root ganglion (DRG) using monopolar pulsed radiofrequency (PRF), which is a non- or minimally neurodestructive technique, is not efficacious in all patients. This study aimed to determine the safety and clinical efficacy of bipolar high-voltage, long-duration PRF on the DRG in PHN patients. Self before-after controlled clinical trial. Department of Pain Medicine, the First Affiliated Hospital of China Medical University. Ninety patients diagnosed with PHN for > 3months were included. Bipolar high-voltage, long-duration PRF at 42°C for 900 seconds was applied after the induction of paresthesias covered the regions of hyperalgesic skin. The therapeutic effects were evaluated using a visual analog scale (VAS) and the 36-item Short Form health survey (SF-36) before treatment and one, 4, 8, and 12 weeks after PRF. The VAS scores at one, 4, 8, and 12 weeks after PRF treatment were significantly lower than before treatment (P < 0.001). The SF-36 scores, which included physical functioning, physical role, bodily pain, general health perceptions, vitality, social function, emotional role, and the mental health index, were significantly improved up to 12 weeks after PRF treatment (P < 0.001). No serious adverse effects were identified following treatment. The main adverse reactions included pain, tachycardia, and high blood pressure (especially when the field strength was enhanced). Single center study, relatively small number of patients, lack of a control group. Bipolar high-voltage, long-duration PRF on the DRG is an effective and safe therapeutic alternative for PHN patients. This treatment could improve the quality of life of PHN patients. NO ChiCTR-OCS-14005461.

Efficient -2 frameshifting by mammalian ribosomes to synthesize an additional arterivirus protein.

PubMed

Fang, Ying; Treffers, Emmely E; Li, Yanhua; Tas, Ali; Sun, Zhi; van der Meer, Yvonne; de Ru, Arnoud H; van Veelen, Peter A; Atkins, John F; Snijder, Eric J; Firth, Andrew E

2012-10-23

Programmed -1 ribosomal frameshifting (-1 PRF) is a gene-expression mechanism used to express many viral and some cellular genes. In contrast, efficient natural utilization of -2 PRF has not been demonstrated previously in eukaryotic systems. Like all nidoviruses, members of the Arteriviridae (a family of positive-stranded RNA viruses) express their replicase polyproteins pp1a and pp1ab from two long ORFs (1a and 1b), where synthesis of pp1ab depends on -1 PRF. These polyproteins are posttranslationally cleaved into at least 13 functional nonstructural proteins. Here we report that porcine reproductive and respiratory syndrome virus (PRRSV), and apparently most other arteriviruses, use an additional PRF mechanism to access a conserved alternative ORF that overlaps the nsp2-encoding region of ORF1a in the +1 frame. We show here that this ORF is translated via -2 PRF at a conserved G_GUU_UUU sequence (underscores separate ORF1a codons) at an estimated efficiency of around 20%, yielding a transframe fusion (nsp2TF) with the N-terminal two thirds of nsp2. Expression of nsp2TF in PRRSV-infected cells was verified using specific Abs, and the site and direction of frameshifting were determined via mass spectrometric analysis of nsp2TF. Further, mutagenesis showed that the frameshift site and an unusual frameshift-stimulatory element (a conserved CCCANCUCC motif 11 nucleotides downstream) are required to direct efficient -2 PRF. Mutations preventing nsp2TF expression impair PRRSV replication and produce a small-plaque phenotype. Our findings demonstrate that -2 PRF is a functional gene-expression mechanism in eukaryotes and add another layer to the complexity of arterivirus genome expression.

Pulsed radiofrequency of the composite nerve supply to the knee joint as a new technique for relieving osteoarthritic pain: a preliminary report.

PubMed

Vas, Lakshmi; Pai, Renuka; Khandagale, Nishigandha; Pattnaik, Manorama

2014-01-01

We report a new technique for pulsed radiofrequency (PRF) of the entire nerve supply of the knee as an option in treating osteoarthritis (OA) of knee. We targeted both sensory and motor nerves supplying all the structures around the knee: joint, muscles, and skin to address the entire nociception and stiffness leading to peripheral and central sensitization in osteoarthritis. Ten patients with pain, stiffness, and loss of function in both knees were treated with ultrasonography (USG) guided PRF of saphenous, tibial, and common peroneal nerves along with subsartorial, peripatellar, and popliteal plexuses. USG guided PRF of the femoral nerve was also done to address the innervation of the quadriceps muscle. Assessment of pain (Numerical Rating Scale [NRS], pain DETECT, knee function [Western Ontario and McMaster Universities Osteoarthritis Index- WOMAC]) were documented pre and post PRF at 3 and 6 months. Knee radiographs (Kellgren-Lawrence [K-L] grading) were done before PRF and one week later. All the patients showed a sustained improvement of NRS, pain DETECT, and WOMAC at 3 and 6 months. The significant improvement of patellar position and tibio-femoral joint space was concordant with the patient's reporting of improvement in stiffness and pain. The sustained pain relief and muscle relaxation enabled the patients to optimize physiotherapy thereby improving endurance training to include the daily activities of life. We conclude that OA knee pain is a product of neuromyopathy and that PRF of the sensory and motor nerves appeared to be a safe, effective, and minimally invasive technique. The reduction of pain and stiffness improved the knee function and probably reduced the peripheral and central sensitization.

The Listeria monocytogenes Bile Stimulon under Acidic Conditions Is Characterized by Strain-Specific Patterns and the Upregulation of Motility, Cell Wall Modification Functions, and the PrfA Regulon

PubMed Central

Guariglia-Oropeza, Veronica; Orsi, Renato H.; Guldimann, Claudia; Wiedmann, Martin; Boor, Kathryn J.

2018-01-01

Listeria monocytogenes uses a variety of transcriptional regulation strategies to adapt to the extra-host environment, the gastrointestinal tract, and the intracellular host environment. While the alternative sigma factor SigB has been proposed to be a key transcriptional regulator that facilitates L. monocytogenes adaptation to the gastrointestinal environment, the L. monocytogenes' transcriptional response to bile exposure is not well-understood. RNA-seq characterization of the bile stimulon was performed in two L. monocytogenes strains representing lineages I and II. Exposure to bile at pH 5.5 elicited a large transcriptomic response with ~16 and 23% of genes showing differential transcription in 10403S and H7858, respectively. The bile stimulon includes genes involved in motility and cell wall modification mechanisms, as well as genes in the PrfA regulon, which likely facilitate survival during the gastrointestinal stages of infection that follow bile exposure. The fact that bile exposure induced the PrfA regulon, but did not induce further upregulation of the SigB regulon (beyond that expected by exposure to pH 5.5), suggests a model where at the earlier stages of gastrointestinal infection (e.g., acid exposure in the stomach), SigB-dependent gene expression plays an important role. Subsequent exposure to bile induces the PrfA regulon, potentially priming L. monocytogenes for subsequent intracellular infection stages. Some members of the bile stimulon showed lineage- or strain-specific distribution when 27 Listeria genomes were analyzed. Even though sigB null mutants showed increased sensitivity to bile, the SigB regulon was not found to be upregulated in response to bile beyond levels expected by exposure to pH 5.5. Comparison of wildtype and corresponding ΔsigB strains newly identified 26 SigB-dependent genes, all with upstream putative SigB-dependent promoters. PMID:29467736

Platelet-Rich Fibrin Promotes Periodontal Regeneration and Enhances Alveolar Bone Augmentation

PubMed Central

Li, Qi; Pan, Shuang; Dangaria, Smit J.; Gopinathan, Gokul; Kolokythas, Antonia; Chu, Shunli; Geng, Yajun; Zhou, Yanmin; Luan, Xianghong

2013-01-01

In the present study we have determined the suitability of platelet-rich fibrin (PRF) as a complex scaffold for periodontal tissue regeneration. Replacing PRF with its major component fibrin increased mineralization in alveolar bone progenitors when compared to periodontal progenitors, suggesting that fibrin played a substantial role in PRF-induced osteogenic lineage differentiation. Moreover, there was a 3.6-fold increase in the early osteoblast transcription factor RUNX2 and a 3.1-fold reduction of the mineralization inhibitor MGP as a result of PRF application in alveolar bone progenitors, a trend not observed in periodontal progenitors. Subcutaneous implantation studies revealed that PRF readily integrated with surrounding tissues and was partially replaced with collagen fibers 2 weeks after implantation. Finally, clinical pilot studies in human patients documented an approximately 5 mm elevation of alveolar bone height in tandem with oral mucosal wound healing. Together, these studies suggest that PRF enhances osteogenic lineage differentiation of alveolar bone progenitors more than of periodontal progenitors by augmenting osteoblast differentiation, RUNX2 expression, and mineralized nodule formation via its principal component fibrin. They also document that PRF functions as a complex regenerative scaffold promoting both tissue-specific alveolar bone augmentation and surrounding periodontal soft tissue regeneration via progenitor-specific mechanisms. PMID:23586051

Platelet-rich fibrin promotes periodontal regeneration and enhances alveolar bone augmentation.

PubMed

Li, Qi; Pan, Shuang; Dangaria, Smit J; Gopinathan, Gokul; Kolokythas, Antonia; Chu, Shunli; Geng, Yajun; Zhou, Yanmin; Luan, Xianghong

2013-01-01

In the present study we have determined the suitability of platelet-rich fibrin (PRF) as a complex scaffold for periodontal tissue regeneration. Replacing PRF with its major component fibrin increased mineralization in alveolar bone progenitors when compared to periodontal progenitors, suggesting that fibrin played a substantial role in PRF-induced osteogenic lineage differentiation. Moreover, there was a 3.6-fold increase in the early osteoblast transcription factor RUNX2 and a 3.1-fold reduction of the mineralization inhibitor MGP as a result of PRF application in alveolar bone progenitors, a trend not observed in periodontal progenitors. Subcutaneous implantation studies revealed that PRF readily integrated with surrounding tissues and was partially replaced with collagen fibers 2 weeks after implantation. Finally, clinical pilot studies in human patients documented an approximately 5 mm elevation of alveolar bone height in tandem with oral mucosal wound healing. Together, these studies suggest that PRF enhances osteogenic lineage differentiation of alveolar bone progenitors more than of periodontal progenitors by augmenting osteoblast differentiation, RUNX2 expression, and mineralized nodule formation via its principal component fibrin. They also document that PRF functions as a complex regenerative scaffold promoting both tissue-specific alveolar bone augmentation and surrounding periodontal soft tissue regeneration via progenitor-specific mechanisms.

The metabolic regulator CodY links L. monocytogenes metabolism to virulence by directly activating the virulence regulatory gene, prfA

PubMed Central

Lobel, Lior; Sigal, Nadejda; Borovok, Ilya; Belitsky, Boris R.; Sonenshein, Abraham L.; Herskovits, Anat A.

2015-01-01

Summary Metabolic adaptations are critical to the ability of bacterial pathogens to grow within host cells and are normally preceded by sensing of host-specific metabolic signals, which in turn can influence the pathogen's virulence state. Previously, we reported that the intracellular bacterial pathogen Listeria monocytogenes responds to low availability of branched-chain amino acids (BCAA) within mammalian cells by up-regulating both BCAA biosynthesis and virulence genes. The induction of virulence genes required the BCAA-responsive transcription regulator, CodY, but the molecular mechanism governing this mode of regulation was unclear. In this report, we demonstrate that CodY directly binds the coding sequence of the L. monocytogenes master virulence activator gene, prfA, 15 nt downstream of its start codon, and that this binding results in up-regulation of prfA transcription specifically under low concentrations of BCAA. Mutating this site abolished CodY binding and reduced prfA transcription in macrophages, and attenuated bacterial virulence in mice. Notably, the mutated binding site did not alter prfA transcription or PrfA activity under other conditions that are known to activate PrfA, such as during growth in the presence of glucose-1-phosphate. This study highlights the tight crosstalk between L. monocytogenes metabolism and virulence' while revealing novel features of CodY-mediated regulation. PMID:25430920

Patient-centered evaluation of microsurgical management of gingival recession using coronally advanced flap with platelet-rich fibrin or amnion membrane: A comparative analysis

PubMed Central

Agarwal, Sumit Kumar; Jhingran, Rajesh; Bains, Vivek Kumar; Srivastava, Ruchi; Madan, Rohit; Rizvi, Iram

2016-01-01

Objective: To evaluate the efficacy of coronally advanced flap (CAF) procedure under microsurgical approach for the management of Miller's Class I and II gingival recession defects with the use of either platelet-rich fibrin (PRF) or amnion membrane (AM) in comparison to CAF alone. Materials and Methods: A total of 45 sites with Miller's Class I or II gingival recession defect were randomly distributed for: Experimental Group I (CAF with PRF) sites (n = 15) which were treated with the microsurgical approach using CAF along with PRF; experimental Group II (CAF with AM) sites (n = 15) were treated with the microsurgical approach using CAF along with AM; control Group III (CAF alone) sites (n = 15) were treated with the microsurgical approach using CAF alone. Vertical gingival recession (VGR), horizontal gingival recession (HGR), gingival thickness (GT) (using transgingival probing [TGP] and ultrasonography [USG]) and patients’ response and acceptance were documented at baseline, 3 months and 6 months after surgical interventions. Results: CAF alone and in combination with PRF or AM, were effective techniques for root coverage with average VGR values of 1.47 ± 0.92 mm (56%), 0.67 ± 1.23 mm (36%) and 0.60 ± 1.06 mm (33%) in Group I (CAF with PRF), Group II (CAF with AM), and Group III (CAF alone), respectively. Complete coverage (100%) was obtained in 33.3% sites of Group I (CAF with PRF), 26.6% sites of Group II (CAF with AM) and 13.3% in Group III (CAF alone). Patients’ response and acceptance for surgical treatment modality in terms of patient esthetic score and decrease in hypersensitivity score was highest for Group I (CAF with PRF), whereas patient comfort score was highest for Group II (CAF with AM). At 6 months follow-up, significant increase in GT measurements (using TGP and USG) in Group I (CAF with PRF), whereas, nonsignificant increase for Group II (CAF with AM) and no change or decrease for Group III (CAF alone) as compared to baseline was observed. Conclusion: The present study observed enhancement in root coverage when PRF or AM are used in conjunction with CAF as compared to CAF alone. These results are based on 6-month follow-up. Therefore, the long-term evaluation may be necessary to appreciate the clinical effect of autologous PRF and AM. PMID:27011751

Comparing different stimulus configurations for population receptive field mapping in human fMRI

PubMed Central

Alvarez, Ivan; de Haas, Benjamin; Clark, Chris A.; Rees, Geraint; Schwarzkopf, D. Samuel

2015-01-01

Population receptive field (pRF) mapping is a widely used approach to measuring aggregate human visual receptive field properties by recording non-invasive signals using functional MRI. Despite growing interest, no study to date has systematically investigated the effects of different stimulus configurations on pRF estimates from human visual cortex. Here we compared the effects of three different stimulus configurations on a model-based approach to pRF estimation: size-invariant bars and eccentricity-scaled bars defined in Cartesian coordinates and traveling along the cardinal axes, and a novel simultaneous “wedge and ring” stimulus defined in polar coordinates, systematically covering polar and eccentricity axes. We found that the presence or absence of eccentricity scaling had a significant effect on goodness of fit and pRF size estimates. Further, variability in pRF size estimates was directly influenced by stimulus configuration, particularly for higher visual areas including V5/MT+. Finally, we compared eccentricity estimation between phase-encoded and model-based pRF approaches. We observed a tendency for more peripheral eccentricity estimates using phase-encoded methods, independent of stimulus size. We conclude that both eccentricity scaling and polar rather than Cartesian stimulus configuration are important considerations for optimal experimental design in pRF mapping. While all stimulus configurations produce adequate estimates, simultaneous wedge and ring stimulation produced higher fit reliability, with a significant advantage in reduced acquisition time. PMID:25750620

Increased vascularization during early healing after biologic augmentation in repair of chronic rotator cuff tears using autologous leukocyte- and platelet-rich fibrin (L-PRF): a prospective randomized controlled pilot trial.

PubMed

Zumstein, Matthias A; Rumian, Adam; Lesbats, Virginie; Schaer, Michael; Boileau, Pascal

2014-01-01

We hypothesized that arthroscopic rotator cuff repairs using leukocyte- and platelet-rich fibrin (L-PRF) in a standardized, modified protocol is technically feasible and results in a higher vascularization response and watertight healing rate during early healing. Twenty patients with chronic rotator cuff tears were randomly assigned to 2 treatment groups. In the test group (N = 10), L-PRF was added in between the tendon and the bone during arthroscopic rotator cuff repair. The second group served as control (N = 10). They received the same arthroscopic treatment without the use of L-PRF. We used a double-row tension band technique. Clinical examinations including subjective shoulder value, visual analog scale, Constant, and Simple Shoulder Test scores and measurement of the vascularization with power Doppler ultrasonography were made at 6 and 12 weeks. There have been no postoperative complications. At 6 and 12 weeks, there was no significant difference in the clinical scores between the test and the control groups. The mean vascularization index of the surgical tendon-to-bone insertions was always significantly higher in the L-PRF group than in the contralateral healthy shoulders at 6 and 12 weeks (P = .0001). Whereas the L-PRF group showed a higher vascularization compared with the control group at 6 weeks (P = .001), there was no difference after 12 weeks of follow-up (P = .889). Watertight healing was obtained in 89% of the repaired cuffs. Arthroscopic rotator cuff repair with the application of L-PRF is technically feasible and yields higher early vascularization. Increased vascularization may potentially predispose to an increased and earlier cellular response and an increased healing rate. Copyright © 2014 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Mosby, Inc. All rights reserved.

Hemisphere-Dependent Attentional Modulation of Human Parietal Visual Field Representations

PubMed Central

Silver, Michael A.

2015-01-01

Posterior parietal cortex contains several areas defined by topographically organized maps of the contralateral visual field. However, recent studies suggest that ipsilateral stimuli can elicit larger responses in the right than left hemisphere within these areas, depending on task demands. Here we determined the effects of spatial attention on the set of visual field locations (the population receptive field [pRF]) that evoked a response for each voxel in human topographic parietal cortex. A two-dimensional Gaussian was used to model the pRF in each voxel, and we measured the effects of attention on not only the center (preferred visual field location) but also the size (visual field extent) of the pRF. In both hemispheres, larger pRFs were associated with attending to the mapping stimulus compared with attending to a central fixation point. In the left hemisphere, attending to the stimulus also resulted in more peripheral preferred locations of contralateral representations, compared with attending fixation. These effects of attention on both pRF size and preferred location preserved contralateral representations in the left hemisphere. In contrast, attentional modulation of pRF size but not preferred location significantly increased representation of the ipsilateral (right) visual hemifield in right parietal cortex. Thus, attention effects in topographic parietal cortex exhibit hemispheric asymmetries similar to those seen in hemispatial neglect. Our findings suggest potential mechanisms underlying the behavioral deficits associated with this disorder. PMID:25589746

Spontaneous Loss of Virulence in Natural Populations of Listeria monocytogenes.

PubMed

Maury, Mylène M; Chenal-Francisque, Viviane; Bracq-Dieye, Hélène; Han, Lei; Leclercq, Alexandre; Vales, Guillaume; Moura, Alexandra; Gouin, Edith; Scortti, Mariela; Disson, Olivier; Vázquez-Boland, José A; Lecuit, Marc

2017-11-01

The pathogenesis of Listeria monocytogenes depends on the ability of this bacterium to escape from the phagosome of the host cells via the action of the pore-forming toxin listeriolysin O (LLO). Expression of the LLO-encoding gene ( hly ) requires the transcriptional activator PrfA, and both hly and prfA genes are essential for L. monocytogenes virulence. Here, we used the hemolytic activity of LLO as a phenotypic marker to screen for spontaneous virulence-attenuating mutations in L. monocytogenes Sixty nonhemolytic isolates were identified among a collection of 57,820 confirmed L. monocytogenes strains isolated from a variety of sources (0.1%). In most cases (56/60; 93.3%), the nonhemolytic phenotype resulted from nonsense, missense, or frameshift mutations in prfA Five strains carried hly mutations leading to a single amino acid substitution (G299V) or a premature stop codon causing strong virulence attenuation in mice. In one strain, both hly and gshF (encoding a glutathione synthase required for full PrfA activity) were missing due to genomic rearrangements likely caused by a transposable element. The PrfA/LLO loss-of-function (PrfA - /LLO - ) mutants belonged to phylogenetically diverse clades of L. monocytogenes , and most were identified among nonclinical strains (57/60). Consistent with the rare occurrence of loss-of-virulence mutations, we show that prfA and hly are under purifying selection. Although occurring at a low frequency, PrfA - /LLO - mutational events in L. monocytogenes lead to niche restriction and open an evolutionary path for obligate saprophytism in this facultative intracellular pathogen. Copyright © 2017 Maury et al.

Spontaneous Loss of Virulence in Natural Populations of Listeria monocytogenes

PubMed Central

Maury, Mylène M.; Chenal-Francisque, Viviane; Bracq-Dieye, Hélène; Han, Lei; Leclercq, Alexandre; Vales, Guillaume; Moura, Alexandra; Gouin, Edith; Scortti, Mariela; Disson, Olivier

2017-01-01

ABSTRACT The pathogenesis of Listeria monocytogenes depends on the ability of this bacterium to escape from the phagosome of the host cells via the action of the pore-forming toxin listeriolysin O (LLO). Expression of the LLO-encoding gene (hly) requires the transcriptional activator PrfA, and both hly and prfA genes are essential for L. monocytogenes virulence. Here, we used the hemolytic activity of LLO as a phenotypic marker to screen for spontaneous virulence-attenuating mutations in L. monocytogenes. Sixty nonhemolytic isolates were identified among a collection of 57,820 confirmed L. monocytogenes strains isolated from a variety of sources (0.1%). In most cases (56/60; 93.3%), the nonhemolytic phenotype resulted from nonsense, missense, or frameshift mutations in prfA. Five strains carried hly mutations leading to a single amino acid substitution (G299V) or a premature stop codon causing strong virulence attenuation in mice. In one strain, both hly and gshF (encoding a glutathione synthase required for full PrfA activity) were missing due to genomic rearrangements likely caused by a transposable element. The PrfA/LLO loss-of-function (PrfA−/LLO−) mutants belonged to phylogenetically diverse clades of L. monocytogenes, and most were identified among nonclinical strains (57/60). Consistent with the rare occurrence of loss-of-virulence mutations, we show that prfA and hly are under purifying selection. Although occurring at a low frequency, PrfA−/LLO− mutational events in L. monocytogenes lead to niche restriction and open an evolutionary path for obligate saprophytism in this facultative intracellular pathogen. PMID:28827366

Achilles Tendon Open Surgical Treatment With Platelet-Rich Fibrin Matrix Augmentation: Biomechanical Evaluation.

PubMed

Alviti, Federica; Gurzì, Michele; Santilli, Valter; Paoloni, Marco; Padua, Roberto; Bernetti, Andrea; Bernardi, Marco; Mangone, Massimiliano

The relationship between surgical technique and ankle biomechanical properties after surgery for acute rupture of the Achilles tendon (ATR) has not yet been fully investigated. Platelet-rich fibrin (PRF) matrices seem to play a central role in the complex processes of tendon healing. Our aim was to analyze the biomechanical characteristics, stiffness, and mechanical work of the ankle during walking in patients who had undergone surgery after ATR with and without PRF augmentation. We performed a retrospective review of all consecutive patients who had been treated with surgical repair after ATR. Of the 20 male subjects enrolled, 9 (45%) had undergone conventional open repair of the Achilles tendon using the Krackow technique (no-PRF) and 11 (55%) had undergone surgery with PRF augmentation. An additional 8 healthy subjects were included as a control group. A gait analysis evaluation was performed at 6 months after surgery. The percentage of the stance time of the operated leg, double-support time of the healthy leg, and net work of the ankle during the gait cycle showed statistically significant differences between the no-PRF and the healthy group (p < .005). No differences were found between the PRF and healthy groups. Treatment with suture and PRF augmentation could result in significant functional improvements in term of efficiency of motion. Copyright © 2017 American College of Foot and Ankle Surgeons. Published by Elsevier Inc. All rights reserved.

Deletion of the Ustilago maydis ortholog of the Aspergillus sporulation regulator medA affects mating and virulence through pheromone response

USDA-ARS?s Scientific Manuscript database

Mating of compatible haploid cells of Ustilago maydis is essential for infection and disease development in the host. For mating and subsequent filamentous growth and pathogenicity, the transcription factor, prf1 is necessary. Prf1 is in turn regulated by the cAMP and MAPK pathways and other regul...

A case report of novel mutation in PRF1 gene, which causes familial autosomal recessive hemophagocytic lymphohistiocytosis.

PubMed

Bordbar, Mohammad Reza; Modarresi, Farzaneh; Farazi Fard, Mohammad Ali; Dastsooz, Hassan; Shakib Azad, Nader; Faghihi, Mohammad Ali

2017-05-03

Hemophagocytic Lymphohistiocytosis (HLH) is a life-threatening immunodeficiency and multi-organ disease that affects people of all ages and ethnic groups. Common symptoms and signs of this disease are high fever, hepatosplenomegaly, and cytopenias. Familial form of HLH disease, which is an autosomal recessive hematological disorder is due to disease-causing mutations in several genes essential for NK and T-cell granule-mediated cytotoxic function. For an effective cytotoxic response from cytotoxic T lymphocyte or NK cell encountering an infected cell or tumor cell, different processes are required, including trafficking, docking, priming, membrane fusion, and entry of cytotoxic granules into the target cell leading to apoptosis. Therefore, genes involved in these steps play important roles in the pathogenesis of HLH disease which include PRF1, UNC13D (MUNC13-4), STX11, and STXBP2 (MUNC18-2). Here, we report a novel missense mutation in an 8-year-old boy suffered from hepatosplenomegaly, hepatitis, epilepsy and pancytopenia. The patient was born to a first-cousin parents with no previous documented disease in his parents. To identify mutated gene in the proband, Whole Exome Sequencing (WES) utilizing next generation sequencing was used on an Illumina HiSeq 2000 platform on DNA sample from the patient. Results showed a novel deleterious homozygous missense mutation in PRF1 gene (NM_001083116: exon3: c. 1120 T > G, p.W374G) in the patient and then using Sanger sequencing it was confirmed in the proband and his parents. Since his parents were heterozygous for the identified mutation, autosomal recessive pattern of inheritance was confirmed in the family. Our study identified a rare new pathogenic missense mutation in PRF1 gene in patient with HLH disease and it is the first report of mutation in PRF1 in Iranian patients with this disease.

Domestication-driven Gossypium profilin 1 (GhPRF1) gene transduces early flowering phenotype in tobacco by spatial alteration of apical/floral-meristem related gene expression.

PubMed

Pandey, Dhananjay K; Chaudhary, Bhupendra

2016-05-13

Plant profilin genes encode core cell-wall structural proteins and are evidenced for their up-regulation under cotton domestication. Notwithstanding striking discoveries in the genetics of cell-wall organization in plants, little is explicit about the manner in which profilin-mediated molecular interplay and corresponding networks are altered, especially during cellular signalling of apical meristem determinacy and flower development. Here we show that the ectopic expression of GhPRF1 gene in tobacco resulted in the hyperactivation of apical meristem and early flowering phenotype with increased flower number in comparison to the control plants. Spatial expression alteration in CLV1, a key meristem-determinacy gene, is induced by the GhPRF1 overexpression in a WUS-dependent manner and mediates cell signalling to promote flowering. But no such expression alterations are recorded in the GhPRF1-RNAi lines. The GhPRF1 transduces key positive flowering regulator AP1 gene via coordinated expression of FT4, SOC1, FLC1 and FT1 genes involved in the apical-to-floral meristem signalling cascade which is consistent with our in silico profilin interaction data. Remarkably, these positive and negative flowering regulators are spatially controlled by the Actin-Related Protein (ARP) genes, specifically ARP4 and ARP6 in proximate association with profilins. This study provides a novel and systematic link between GhPRF1 gene expression and the flower primordium initiation via up-regulation of the ARP genes, and an insight into the functional characterization of GhPRF1 gene acting upstream to the flowering mechanism. Also, the transgenic plants expressing GhPRF1 gene show an increase in the plant height, internode length, leaf size and plant vigor. Overexpression of GhPRF1 gene induced early and increased flowering in tobacco with enhanced plant vigor. During apical meristem determinacy and flower development, the GhPRF1 gene directly influences key flowering regulators through ARP-genes, indicating for its role upstream in the apical-to-floral meristem signalling cascade.

Treatment of chronic lumbosacral radicular pain using adjuvant pulsed radiofrequency: a randomized controlled study.

PubMed

Koh, Wonuk; Choi, Seong-Soo; Karm, Myong Hwan; Suh, Jeong Hun; Leem, Jeong Gil; Lee, Jae Do; Kim, Young Ki; Shin, Jinwoo

2015-03-01

The objective of this study was to determine the effects of combining pulsed radiofrequency (PRF) treatment and transforaminal epidural injection (TFEI) to treat patients with chronic refractory lumbar radicular pain caused by lumbar spinal stenosis. Randomized control trial. Interventional pain management practice. Sixty-two patients were assigned to the study groups (PRF group = 31; control group = 31). Under fluoroscopic guidance, the RF needle was positioned close to the lumbar dorsal root ganglion. The PRF group received 3 cycles of PRF treatment, and sensory stimulation without RF lesioning was applied to the control group. After PRF or sham lesioning, a local anesthetic with steroid was injected. The primary outcome of a successful response was defined as: 1) ≥50% or 4-point pain reduction in the numerical rating scale (NRS) without an increase in the Oswestry disability index (ODI) or medication quantification scale (MQS), or mean score <4 in the global perceived effect (GPE) scale; or 2) ≥30% or 2-point pain reduction in NRS with a simultaneous decrease in ODI, MQS, or ≥6 points in the GPE scale. The number of patients with successful treatment results was higher in the PRF group at 2 months (P = 0.032) and 3 months (P = 0.018). No significant differences were observed in terms of the secondary outcome variables between the 2 groups. The TFEI provided significant short-term pain relief and PRF can be applied in conjunction with TFEI to achieve higher treatment efficacy compared with TFEI alone. Wiley Periodicals, Inc.

Ginsenoside Rg1 and platelet-rich fibrin enhance human breast adipose-derived stem cells function for soft tissue regeneration

PubMed Central

Li, Hong-Mian; Peng, Qi-Liu; Huang, Min-Hong; Li, De-Quan; Liang, Yi-Dan; Chi, Gang-Yi; Li, De-Hui; Yu, Bing-Chao; Huang, Ji-Rong

2016-01-01

Adipose-derived stem cells (ASCs) can be used to repair soft tissue defects, wounds, burns, and scars and to regenerate various damaged tissues. The cell differentiation capacity of ASCs is crucial for engineered adipose tissue regeneration in reconstructive and plastic surgery. We previously reported that ginsenoside Rg1 (G-Rg1 or Rg1) promotes proliferation and differentiation of ASCs in vitro and in vivio. Here we show that both G-Rg1 and platelet-rich fibrin (PRF) improve the proliferation, differentiation, and soft tissue regeneration capacity of human breast adipose-derived stem cells (HBASCs) on collagen type I sponge scaffolds in vitro and in vivo. Three months after transplantation, tissue wet weight, adipocyte number, intracellular lipid, microvessel density, and gene and protein expression of VEGF, HIF-1α, and PPARγ were higher in both G-Rg1- and PRF-treated HBASCs than in control grafts. More extensive new adipose tissue formation was evident after treatment with G-Rg1 or PRF. In summary, G-Rg1 and/or PRF co-administration improves the function of HBASCs for soft tissue regeneration engineering. PMID:27191987

Relationship between the mechanisms of gamma rhythm generation and the magnitude of the macroscopic phase response function in a population of excitatory and inhibitory modified quadratic integrate-and-fire neurons

NASA Astrophysics Data System (ADS)

Akao, Akihiko; Ogawa, Yutaro; Jimbo, Yasuhiko; Ermentrout, G. Bard; Kotani, Kiyoshi

2018-01-01

Gamma oscillations are thought to play an important role in brain function. Interneuron gamma (ING) and pyramidal interneuron gamma (PING) mechanisms have been proposed as generation mechanisms for these oscillations. However, the relation between the generation mechanisms and the dynamical properties of the gamma oscillation are still unclear. Among the dynamical properties of the gamma oscillation, the phase response function (PRF) is important because it encodes the response of the oscillation to inputs. Recently, the PRF for an inhibitory population of modified theta neurons that generate an ING rhythm was computed by the adjoint method applied to the associated Fokker-Planck equation (FPE) for the model. The modified theta model incorporates conductance-based synapses as well as the voltage and current dynamics. Here, we extended this previous work by creating an excitatory-inhibitory (E-I) network using the modified theta model and described the population dynamics with the corresponding FPE. We conducted a bifurcation analysis of the FPE to find parameter regions which generate gamma oscillations. In order to label the oscillatory parameter regions by their generation mechanisms, we defined ING- and PING-type gamma oscillation in a mathematically plausible way based on the driver of the inhibitory population. We labeled the oscillatory parameter regions by these generation mechanisms and derived PRFs via the adjoint method on the FPE in order to investigate the differences in the responses of each type of oscillation to inputs. PRFs for PING and ING mechanisms are derived and compared. We found the amplitude of the PRF for the excitatory population is larger in the PING case than in the ING case. Finally, the E-I population of the modified theta neuron enabled us to analyze the PRFs of PING-type gamma oscillation and the entrainment ability of E and I populations. We found a parameter region in which PRFs of E and I are both purely positive in the case of PING oscillations. The different entrainment abilities of E and I stimulation as governed by the respective PRFs was compared to direct simulations of finite populations of model neurons. We find that it is easier to entrain the gamma rhythm by stimulating the inhibitory population than by stimulating the excitatory population as has been found experimentally.

Platelet-Rich Fibrin Lysate Can Ameliorate Dysfunction of Chronically UVA-Irradiated Human Dermal Fibroblasts.

PubMed

Wirohadidjojo, Yohanes Widodo; Budiyanto, Arief; Soebono, Hardyanto

2016-09-01

To determine whether platelet-rich fibrin lysate (PRF-L) could restore the function of chronically ultraviolet-A (UVA)-irradiated human dermal fibroblasts (HDFs), we isolated and sub-cultured HDFs from six different human foreskins. HDFs were divided into two groups: those that received chronic UVA irradiation (total dosages of 10 J cm⁻²) and those that were not irradiated. We compared the proliferation rates, collagen deposition, and migration rates between the groups and between chronically UVA-irradiated HDFs in control and PRF-L-treated media. Our experiment showed that chronic UVA irradiation significantly decreased (p<0.05) the proliferation rates, migration rates, and collagen deposition of HDFs, compared to controls. Compared to control media, chronically UVA-irradiated HDFs in 50% PRF-L had significantly increased proliferation rates, migration rates, and collagen deposition (p<0.05), and the migration rates and collagen deposition of chronically UVA-irradiated HDFs in 50% PRF-L were equal to those of normal fibroblasts. Based on this experiment, we concluded that PRF-L is a good candidate material for treating UVA-induced photoaging of skin, although the best method for its clinical application remains to be determined.

Vascularization after treatment of gingival recession defects with platelet-rich fibrin or connective tissue graft.

PubMed

Eren, Gülnihal; Kantarcı, Alpdoğan; Sculean, Anton; Atilla, Gül

2016-11-01

The aim of this study was to evaluate histologically the following treatment of bilateral localized gingival recessions with coronally advanced flap (CAF) combined with platelet-rich fibrin (PRF) or subepithelial connective tissue graft (SCTG). Tissue samples were harvested from 14 subjects either 1 or 6 months after the surgeries. The 2-mm punch biopsies were obtained from the mid-portion of the grafted sites. Neutral buffered formalin fixed, paraffin-embedded 5-μm thick tissue sections were stained with hematoxylin eosin and Masson's trichrome in order to analyze the collagen framework, epithelium thickness and rete-peg length. Multiple sequential sections were cut from paraffin-embedded blocks of tissue and immunohistochemically prepared for detection of vascular endothelial growth factor, CD31 and CD34, for the assessment of vascularization. Rete peg formation was significantly increased in the sites treated with PRF compared to the SCTG group after 6 months (p < 0.05). On the contrary, the number of vessels was increased in the SCTG group compared to the PRF group after 6 months (p < 0.05). No statistically significant differences were observed in the collagen density. Staining intensity of CD31 increased in submucosal area of PRF group than SCTG group after 1 month. Higher staining intensity of CD34 was observed in the submucosal area of PRF group compared with SCTG group after 6 months. The results of the present study suggest that in histological evaluation because of its biological compounds, PRF results earlier vessel formation and tissue maturation compared to connective tissue graft. PRF regulated the vascular response associated with an earlier wound healing.

Adenosine A1 Receptors in Mouse Pontine Reticular Formation Depress Breathing, Increase Anesthesia Recovery Time, and Decrease Acetylcholine Release

PubMed Central

Gettys, George C.; Liu, Fang; Kimlin, Ed; Baghdoyan, Helen A.; Lydic, Ralph

2012-01-01

Background Clinical and preclinical data demonstrate the analgesic actions of adenosine. Central administration of adenosine agonists, however, suppresses arousal and breathing by poorly understood mechanisms. This study tested the two-tailed hypothesis that adenosine A1 receptors in the pontine reticular formation (PRF) of C57BL/6J mice modulate breathing, behavioral arousal, and PRF acetylcholine release. Methods Three sets of experiments used 51 mice. First, breathing was measured by plethysmography after PRF microinjection of the adenosine A1 receptor agonist N6-sulfophenyl adenosine (SPA) or saline. Second, mice were anesthetized with isoflurane and time to recovery of righting response (RoRR) was quantified after PRF microinjection of SPA or saline. Third, acetylcholine release in the PRF was measured before and during microdialysis delivery of SPA, the adenosine A1 receptor antagonist 1,3-dipropyl-8-cyclopentylxanthine (DPCPX), or SPA and DPCPX. Results First, SPA significantly decreased respiratory rate (−18%), tidal volume (−12%) and minute ventilation (−16%). Second, SPA concentration accounted for 76% of the variance in RoRR. Third, SPA concentration accounted for a significant amount of the variance in acetylcholine release (52%), RoRR (98%), and breathing rate (86%). DPCPX alone caused a concentration-dependent increase in acetylcholine, decrease in RoRR, and decrease in breathing rate. Coadministration of SPA and DPCPX blocked the SPA-induced decrease in acetylcholine and increase in RoRR. Conclusions Endogenous adenosine acting at adenosine A1 receptors in the PRF modulates breathing, behavioral arousal, and acetylcholine release. The results support the interpretation that an adenosinergic-cholinergic interaction within the PRF comprises one neurochemical mechanism underlying the wakefulness stimulus for breathing. PMID:23263018

Visual motion transforms visual space representations similarly throughout the human visual hierarchy.

PubMed

Harvey, Ben M; Dumoulin, Serge O

2016-02-15

Several studies demonstrate that visual stimulus motion affects neural receptive fields and fMRI response amplitudes. Here we unite results of these two approaches and extend them by examining the effects of visual motion on neural position preferences throughout the hierarchy of human visual field maps. We measured population receptive field (pRF) properties using high-field fMRI (7T), characterizing position preferences simultaneously over large regions of the visual cortex. We measured pRFs properties using sine wave gratings in stationary apertures, moving at various speeds in either the direction of pRF measurement or the orthogonal direction. We find direction- and speed-dependent changes in pRF preferred position and size in all visual field maps examined, including V1, V3A, and the MT+ map TO1. These effects on pRF properties increase up the hierarchy of visual field maps. However, both within and between visual field maps the extent of pRF changes was approximately proportional to pRF size. This suggests that visual motion transforms the representation of visual space similarly throughout the visual hierarchy. Visual motion can also produce an illusory displacement of perceived stimulus position. We demonstrate perceptual displacements using the same stimulus configuration. In contrast to effects on pRF properties, perceptual displacements show only weak effects of motion speed, with far larger speed-independent effects. We describe a model where low-level mechanisms could underlie the observed effects on neural position preferences. We conclude that visual motion induces similar transformations of visuo-spatial representations throughout the visual hierarchy, which may arise through low-level mechanisms. Copyright © 2015 Elsevier Inc. All rights reserved.

Adenosine A(1) receptors in mouse pontine reticular formation depress breathing, increase anesthesia recovery time, and decrease acetylcholine release.

PubMed

Gettys, George C; Liu, Fang; Kimlin, Ed; Baghdoyan, Helen A; Lydic, Ralph

2013-02-01

Clinical and preclinical data demonstrate the analgesic actions of adenosine. Central administration of adenosine agonists, however, suppresses arousal and breathing by poorly understood mechanisms. This study tested the two-tailed hypothesis that adenosine A1 receptors in the pontine reticular formation (PRF) of C57BL/6J mice modulate breathing, behavioral arousal, and PRF acetylcholine release. Three sets of experiments used 51 mice. First, breathing was measured by plethysmography after PRF microinjection of the adenosine A1 receptor agonist N-sulfophenyl adenosine (SPA) or saline. Second, mice were anesthetized with isoflurane and the time to recovery of righting response (RoRR) was quantified after a PRF microinjection of SPA or saline. Third, acetylcholine release in the PRF was measured before and during microdialysis delivery of SPA, the adenosine A1 receptor antagonist 1, 3-dipropyl-8-cyclopentylxanthine, or SPA and 1, 3-dipropyl-8-cyclopentylxanthine. First, SPA significantly decreased respiratory rate (-18%), tidal volume (-12%), and minute ventilation (-16%). Second, SPA concentration accounted for 76% of the variance in RoRR. Third, SPA concentration accounted for a significant amount of the variance in acetylcholine release (52%), RoRR (98%), and breathing rate (86%). 1, 3-dipropyl-8-cyclopentylxanthine alone caused a concentration-dependent increase in acetylcholine, a decrease in RoRR, and a decrease in breathing rate. Coadministration of SPA and 1, 3-dipropyl-8-cyclopentylxanthine blocked the SPA-induced decrease in acetylcholine and increase in RoRR. Endogenous adenosine acting at adenosine A1 receptors in the PRF modulates breathing, behavioral arousal, and acetylcholine release. The results support the interpretation that an adenosinergic-cholinergic interaction within the PRF comprises one neurochemical mechanism underlying the wakefulness stimulus for breathing.

Surface finish quality of the outer AXAF mirror pair based on x ray measurements of the VETA-I

NASA Technical Reports Server (NTRS)

Hughes, John P.; Schwartz, Daniel A.; Szentgyorgyi, Andrew; Vanspeybroeck, Leon; Zhao, Ping

1992-01-01

We employ the X-ray measurements of the VETA-I taken at the X-Ray Calibration Facility (XRCF) of the Marshall Space Flight Center (MSFC) to extract information about the surface finish quality of the outermost pair of AXAF mirrors. The particular measurements we consider are one dimensional scans of the core of the point response function (PRF) (full width half maximum (FWHM) scans), the encircled energy as a function of radius, and one dimensional scans of the wings of the PRF. We discuss briefly our ray trace model which incorporates the numerous effects present in the VETA-I test, such as the finite source distance, the size and shape of the X-ray source, the residual gravitational distortions of the optic, the despace of the VETA-I, and particulate contamination. We show how the data constrain the amplitude of mirror surface deviations for spatial frequencies greater than about 0.1 mm(exp -1). Constraints on the average amplitude of circumferential slope errors are derived as well.

Carbachol models of REM sleep: recent developments and new directions.

PubMed

Kubin, L

2001-02-01

Since the early '60s, injections of a broad-spectrum muscarinic cholinergic agonist, carbachol, into the medial pontine reticular formation (mPRF) of cats have been extensively used as a tool with which to study the neural mechanisms of rapid eye movement (REM) sleep. During the last decade, new carbachol models of REM sleep were introduced, including chronically instrumented/behaving rats and "reduced" preparations such as decerebrate or anesthetized cats and rats. The combined results from these distinct models show interspecies similarities and differences. The dual nature, both REM sleep-promoting and wakefulness (or arousal)-promoting, of the cholinergic effects exerted within the mPRF is more strongly expressed in rats than in cats. This strengthens the possibility suggested by earlier central neuronal recordings that active wakefulness and REM sleep have extensive common neuronal substrates, and may have evolved from a common behavioral state. Carbachol studies using different intact and reduced models also suggest that powerful REM sleep episode-terminating effects originate in suprapontine structures. In contrast, the timing of REM sleep-like episodes in decerebrate models is determined by a pontomedullary neuronal network responsible for the generation of an ultradian cycle similar to the basic rest-activity cycle of N. Kleitman. Other presumed species differences, such as the more widespread distribution of carbachol-sensitive sites or the relative failure of carbachol to increase the duration of REM sleep episodes in rats when compared to cats, may be of a quantitative or technical nature. While carbachol and many other neurotransmitters and peptides microinjected into the mPRF evoke, enhance or suppress REM sleep, the most sensitive site(s) of their actions have not been fully mapped, and the nature of the cellular and neurochemical interactions taking place at the sites where carbachol triggers the REM sleep-like state remain largely unknown. Similarly, little is known about the pathways between the mPRF and medial medullary reticular formation, but the existing evidence suggests that they are reciprocal and essential for the generation of both natural and carbachol-induced REM sleep. Studies of the mesopontine cholinergic neurons, which are hypothesized to be the main source of endogenous acetylcholine for the mPRF, need to be extended to neurons of the mPRF and cells located functionally downstream from this important site for REM sleep, or both REM sleep and active wakefulness.

A Naturally Occurring Mutation K220T in the Pleiotropic Activator PrfA of Listeria Monocytogenes Results in a Loss of Virulence Due to Decreasing DNA-Binding Affinity

DOE Office of Scientific and Technical Information (OSTI.GOV)

Velge,P.; Herler, M.; Johansson, J.

2007-01-01

The sequencing of prfA, encoding the transcriptional regulator of virulence genes, in 26 low-virulence field Listeria monocytogenes strains showed that eight strains exhibited the same single amino-acid substitution: PrfAK220T. These strains exhibited no expression of PrfA-regulated proteins and thus no virulence. This substitution inactivated PrfA, since expression of the PrfAK220T mutant gene in an EGD{Delta}prfA strain did not restore the haemolytic and phosphatidylcholine phospholipase C activities, in contrast to the wild-type prfA gene. The substitution of the lysine at position 220 occurred in the helix H. However, the data showed that the PrfAK220T protein is dimerized just as well asmore » its wild-type counterpart, but does not bind to PrfA-boxes. PrfAK220T did not form a PrfA-DNA complex in electrophoretic mobility shift assays, but low concentrations of CI complexes (PrfAK220T-RNA polymerase-DNA complex) were formed by adding RNA polymerase, suggesting that PrfA interacted with RNA polymerase in solution in the absence of DNA. Formation of some transcriptionally active complexes was confirmed by in vitro runoff transcription assays and quantitative RT-PCR. Crystallographic analyses described the structure of native PrfA and highlighted the key role of allosteric changes in the activity of PrfA and especially the role of the Lys220 in the conformation of the helix-turn-helix (HTH) motif.« less

Comparison of matched sibling donors versus unrelated donors in allogeneic stem cell transplantation for primary refractory acute myeloid leukemia: a study on behalf of the Acute Leukemia Working Party of the EBMT.

PubMed

Brissot, Eolia; Labopin, Myriam; Stelljes, Matthias; Ehninger, Gerhard; Schwerdtfeger, Rainer; Finke, Jürgen; Kolb, Hans-Jochem; Ganser, Arnold; Schäfer-Eckart, Kerstin; Zander, Axel R; Bunjes, Donald; Mielke, Stephan; Bethge, Wolfgang A; Milpied, Noël; Kalhs, Peter; Blau, Igor-Woflgang; Kröger, Nicolaus; Vitek, Antonin; Gramatzki, Martin; Holler, Ernst; Schmid, Christoph; Esteve, Jordi; Mohty, Mohamad; Nagler, Arnon

2017-06-24

Primary refractory acute myeloid leukemia (PRF-AML) is associated with a dismal prognosis. Allogeneic stem cell transplantation (HSCT) in active disease is an alternative therapeutic strategy. The increased availability of unrelated donors together with the significant reduction in transplant-related mortality in recent years have opened the possibility for transplantation to a larger number of patients with PRF-AML. Moreover, transplant from unrelated donors may be associated with stronger graft-mediated anti-leukemic effect in comparison to transplantations from HLA-matched sibling donor, which may be of importance in the setting of PRF-AML. The current study aimed to address the issue of HSCT for PRF-AML and to compare the outcomes of HSCT from matched sibling donors (n = 660) versus unrelated donors (n = 381), for patients with PRF-AML between 2000 and 2013. The Kaplan-Meier estimator, the cumulative incidence function, and Cox proportional hazards regression models were used where appropriate. HSCT provide patients with PRF-AML a 2-year leukemia-free survival and overall survival of about 25 and 30%, respectively. In multivariate analysis, two predictive factors, cytogenetics and time from diagnosis to transplant, were associated with lower leukemia-free survival, whereas Karnofsky performance status at transplant ≥90% was associated with better leukemia-free survival (LFS). Concerning relapse incidence, cytogenetics and time from diagnosis to transplant were associated with increased relapse. Reduced intensity conditioning regimen was the only factor associated with lower non-relapse mortality. HSCT was able to rescue about one quarter of the patients with PRF-AML. The donor type did not have any impact on PRF patients' outcomes. In contrast, time to transplant was a major prognostic factor for LFS. For patients with PRF-AML who do not have a matched sibling donor, HSCT from an unrelated donor is a suitable option, and therefore, initiation of an early search for allocating a suitable donor is indicated.

A Response Function Approach for Rapid Far-Field Tsunami Forecasting

NASA Astrophysics Data System (ADS)

Tolkova, Elena; Nicolsky, Dmitry; Wang, Dailin

2017-08-01

Predicting tsunami impacts at remote coasts largely relies on tsunami en-route measurements in an open ocean. In this work, these measurements are used to generate instant tsunami predictions in deep water and near the coast. The predictions are generated as a response or a combination of responses to one or more tsunameters, with each response obtained as a convolution of real-time tsunameter measurements and a pre-computed pulse response function (PRF). Practical implementation of this method requires tables of PRFs in a 3D parameter space: earthquake location-tsunameter-forecasted site. Examples of hindcasting the 2010 Chilean and the 2011 Tohoku-Oki tsunamis along the US West Coast and beyond demonstrated high accuracy of the suggested technology in application to trans-Pacific seismically generated tsunamis.

A novel platelet concentrate: titanium-prepared platelet-rich fibrin.

PubMed

Tunalı, Mustafa; Özdemir, Hakan; Küçükodacı, Zafer; Akman, Serhan; Yaprak, Emre; Toker, Hülya; Fıratlı, Erhan

2014-01-01

We developed a new product called titanium-prepared platelet-rich fibrin (T-PRF). The T-PRF method is based on the hypothesis that titanium may be more effective in activating platelets than the silica activators used with glass tubes in Chouckroun's leukocyte- and platelet-rich fibrin (L-PRF) method. In this study, we aimed to define the structural characteristics of T-PRF and compare it with L-PRF. Blood samples were collected from 10 healthy male volunteers. The blood samples were drawn using a syringe. Nine milliliters was transferred to a dry glass tube, and 9 mL was transferred to a titanium tube. Half of each clot (i.e., the blood that was clotted using T-PRF or L-PRF) was processed with a scanning electron microscope (SEM). The other half of each clot was processed for fluorescence microscopy analysis and light microscopy analysis. The T-PRF samples seemed to have a highly organized network with continuous integrity compared to the other L-PRF samples. Histomorphometric analysis showed that T-PRF fibrin network covers larger area than L-PRF fibrin network; also fibrin seemed thicker in the T-PRF samples. This is the first human study to define T-PRF as an autogenous leukocyte- and platelet-rich fibrin product. The platelet activation by titanium seems to offer some high characteristics to T-PRF.

The combination use of platelet-rich fibrin and treated dentin matrix for tooth root regeneration by cell homing.

PubMed

Ji, Baohui; Sheng, Lei; Chen, Gang; Guo, Shujuan; Xie, Li; Yang, Bo; Guo, Weihua; Tian, Weidong

2015-01-01

Endogenous regeneration through cell homing provides an alternative approach for tissue regeneration, except cell transplantation, especially considering clinical translation. However, tooth root regeneration through cell homing remains a provocative approach in need of intensive study. Both platelet-rich fibrin (PRF) and treated dentin matrix (TDM) are warehouses of various growth factors, which can promote cell homing. We hypothesized that endogenous stem cells are able to sense biological cues from PRF membrane and TDM, and contribute to the regeneration of tooth root, including soft and hard periodontal tissues. Therefore, the biological effects of canine PRF and TDM on periodontal ligament stem cells (PDLSCs) and bone marrow mesenchymal stem cells (BMSCs) were evaluated respectively in vitro. Beagle dogs were used as orthotopic transplantation model. It was found that PRF significantly recruited and stimulated the proliferation of PDLSCs and BMSCs in vitro. Together, PRF and TDM induced cell differentiation by upregulating the mineralization-related gene expression of bone sialoprotein (BSP) and osteopotin (OPN) after 7 days coculture. In vivo, transplantation of autologous PRF and allogeneic TDM into fresh tooth extraction socket achieved successful root regeneration 3 months postsurgery, characterized by the regeneration of cementum and periodontal ligament (PDL)-like tissues with orientated fibers, indicative of functional restoration. The results suggest that tooth root connected to the alveolar bone by cementum-PDL complex can be regenerated through the implantation of PRF and TDM in a tooth socket microenvironment, probably by homing of BMSCs and PDLSCs. Furthermore, bioactive cues and inductive microenvironment are key factors for endogenous regeneration. This approach provides a tangible pathway toward clinical translation.

Working Memory and Reinforcement Schedule Jointly Determine Reinforcement Learning in Children: Potential Implications for Behavioral Parent Training

PubMed Central

Segers, Elien; Beckers, Tom; Geurts, Hilde; Claes, Laurence; Danckaerts, Marina; van der Oord, Saskia

2018-01-01

Introduction: Behavioral Parent Training (BPT) is often provided for childhood psychiatric disorders. These disorders have been shown to be associated with working memory impairments. BPT is based on operant learning principles, yet how operant principles shape behavior (through the partial reinforcement (PRF) extinction effect, i.e., greater resistance to extinction that is created when behavior is reinforced partially rather than continuously) and the potential role of working memory therein is scarcely studied in children. This study explored the PRF extinction effect and the role of working memory therein using experimental tasks in typically developing children. Methods: Ninety-seven children (age 6–10) completed a working memory task and an operant learning task, in which children acquired a response-sequence rule under either continuous or PRF (120 trials), followed by an extinction phase (80 trials). Data of 88 children were used for analysis. Results: The PRF extinction effect was confirmed: We observed slower acquisition and extinction in the PRF condition as compared to the continuous reinforcement (CRF) condition. Working memory was negatively related to acquisition but not extinction performance. Conclusion: Both reinforcement contingencies and working memory relate to acquisition performance. Potential implications for BPT are that decreasing working memory load may enhance the chance of optimally learning through reinforcement. PMID:29643822

Antioxidant and antimicrobial properties of phenolic rich fraction of Seabuckthorn (Hippophae rhamnoides L.) leaves in vitro.

PubMed

Yogendra Kumar, M S; Tirpude, R J; Maheshwari, D T; Bansal, Anju; Misra, Ksipra

2013-12-15

Phenolic rich fraction (PRF) from Seabuckthorn leaves was prepared by sequential fractionation. Total phenolic content of PRF estimated as gallic acid equivalent was found to be 319.33±7.02 mg/g of PRF. Its major constituents gallic acid, rutin, quercetin-3-galactoside, quercetin-3-glucoside, myricetin, quercetin, kaempferol and isorhamnetin, were found in the range of 1.551-196.89 mg/g of PRF as determined by RP-HPLC. Antioxidant activity of PRF evaluated using 2,2-diphenyl-2-picrylhydrazyl, superoxide and nitric oxide scavenging assays. Reducing power of PRF increased with increasing amount of PRF; the equation of reducing power (y) and amount of PRF (x) was y=8.004x (r(2)=0.99), indicating that reducing ability correlated well with amount of PRF. Antibacterial activity of PRF, tested against certain medically important bacterial species showed growth inhibiting effect against Escherichia coli, Salmonella typhi, Shigella dysenteriae, Streptococcus pneumoniae and Staphylococcus aureus. In conclusion, PRF has potent antioxidant and broad spectrum antibacterial properties. Copyright © 2013 Elsevier Ltd. All rights reserved.

Pulsed Radiofrequency to the Dorsal Root Ganglion in Acute Herpes Zoster and Postherpetic Neuralgia.

PubMed

Kim, Koohyun; Jo, Daehyun; Kim, EungDon

2017-03-01

Latent varicella zoster virus reactivates mainly in sensory ganglia such as the dorsal root ganglion (DRG) or trigeminal ganglion. The DRG contains many receptor channels and is an important region for pain signal transduction. Sustained abnormal electrical activity to the spinal cord via the DRG in acute herpes zoster can result in neuropathic conditions such as postherpetic neuralgia (PHN). Although the efficacy of pulsed radiofrequency (PRF) application to the DRG in various pain conditions has been previously reported, the application of PRF to the DRG in patients with herpes zoster has not yet been studied. The aim of the present study was to compare the clinical effects of PRF to the DRG in patients with herpes zoster to those of PRF to the DRG in patients with PHN. Retrospective comparative study. University hospital pain center in Korea. The medical records of 58 patients who underwent PRF to the DRG due to zoster related pain (herpes zoster or PHN) were retrospectively analyzed. Patients were divided into 2 groups according to the timing of PRF after zoster onset: an early PRF group (within 90 days) and a PHN PRF group (more than 90 days). The efficacy of PRF was assessed by a numeric rating scale (NRS) and by recording patient medication doses before PRF and at one week, 4 weeks, 8 weeks, and 12 weeks after PRF. Pain intensity was decreased after PRF in all participants. However, the degree of pain reduction was significantly higher in the early PRF group. Moreover, more patients discontinued their medication in the early PRF group, and the PRF success rate was also higher in the early PRF group. The relatively small sample size from a single center, short duration of review of medical records, and the retrospective nature of the study. PRF to the DRG is a useful treatment for treatment-resistant cases of herpes zoster and PHN. Particularly in herpes zoster patients with intractable pain, application of PRF to the DRG should be considered for pain control and prevention of PHN.Key words: Pulsed radiofrequency, dorsal root ganglion, herpes zoster, postherpetic neuralgia.

The impact of the centrifuge characteristics and centrifugation protocols on the cells, growth factors, and fibrin architecture of a leukocyte- and platelet-rich fibrin (L-PRF) clot and membrane.

PubMed

Dohan Ehrenfest, David M; Pinto, Nelson R; Pereda, Andrea; Jiménez, Paula; Corso, Marco Del; Kang, Byung-Soo; Nally, Mauricio; Lanata, Nicole; Wang, Hom-Lay; Quirynen, Marc

2018-03-01

L-PRF (leukocyte- and platelet-rich fibrin) is one of the four families of platelet concentrates for surgical use and is widely used in oral and maxillofacial regenerative therapies. The first objective of this article was to evaluate the mechanical vibrations appearing during centrifugation in four models of commercially available table-top centrifuges used to produce L-PRF and the impact of the centrifuge characteristics on the cell and fibrin architecture of a L-PRF clot and membrane. The second objective of this article was to evaluate how changing some parameters of the L-PRF protocol may influence its biological signature, independently from the characteristics of the centrifuge. In the first part, four different commercially available centrifuges were used to produce L-PRF, following the original L-PRF production method (glass-coated plastic tubes, 400 g force, 12 minutes). The tested systems were the original L-PRF centrifuge (Intra-Spin, Intra-Lock, the only CE and FDA cleared system for the preparation of L-PRF) and three other laboratory centrifuges (not CE/FDA cleared for L-PRF): A-PRF 12 (Advanced PRF, Process), LW-UPD8 (LW Scientific) and Salvin 1310 (Salvin Dental). Each centrifuge was opened for inspection, two accelerometers were installed (one radial, one vertical), and data were collected with a spectrum analyzer in two configurations (full-load or half load). All clots and membranes were collected into a sterile surgical box (Xpression kit, Intra-Lock). The exact macroscopic (weights, sizes) and microscopic (photonic and scanning electron microscopy SEM) characteristics of the L-PRF produced with these four different machines were evaluated. In the second part, venous blood was taken in two groups, respectively, Intra-Spin 9 ml glass-coated plastic tubes (Intra-Lock) and A-PRF 10 ml glass tubes (Process). Tubes were immediately centrifuged at 2700 rpm (around 400 g) during 12 minutes to produce L-PRF or at 1500 rpm during 14 minutes to produce A-PRF. All centrifugations were done using the original L-PRF centrifuge (Intra-Spin), as recommended by the two manufacturers. Half of the membranes were placed individually in culture media and transferred in a new tube at seven experimental times (up to 7 days). The releases of transforming growth factor β-1 (TGFβ-1), platelet derived growth factor AB (PDGF-AB), vascular endothelial growth factor (VEGF) and bone morphogenetic protein 2 (BMP-2) were quantified using ELISA kits at these seven experimental times. The remaining membranes were used to evaluate the initial quantity of growth factors of the L-PRF and A-PRF membranes, through forcible extraction. Very significant differences in the level of vibrations at each rotational speed were observed between the four tested centrifuges. The original L-PRF centrifuge (Intra-Spin) was by far the most stable machine in all configurations and always remained under the threshold of resonance, unlike the three other tested machines. At the classical speed of production of L-PRF, the level of undesirable vibrations on the original centrifuge was between 4.5 and 6 times lower than with other centrifuges. Intra-Spin showed the lowest temperature of the tubes. A-PRF and Salvin were both associated with a significant increase in temperature in the tube. Intra-Spin produced the heaviest clot and quantity of exudate among the four techniques. A-PRF and LW produced much lighter, shorter and narrower clots and membranes than the two other centrifuges. Light microscopy analysis showed relatively similar features for all L-PRF types (concentration of cell bodies in the first half). However, SEM illustrated considerable differences between samples. The original Intra-Spin L-PRF showed a strongly polymerized thick fibrin matrix and all cells appeared alive with a normal shape, including the textured surface aspect of activated lymphocytes. The A-PRF, Salvin and LW PRF-like membranes presented a lightly polymerized slim fibrin gel and most of the visible cell bodies appeared destroyed (squashed or shrunk). In the second part of this study, the slow release of the three tested growth factors from original L-PRF membranes was significantly stronger (more than twice stronger, p<0.001) at all experimental times than the release from A-PRF membranes. No trace of BMP2 could be detected in the A-PRF. A slow release of BMP2 was detected during at least 7 days in the original L-PRF. Moreover, the original L-PRF clots and membranes (produced with 9 mL blood) were always significantly larger than the A-PRF (produced with 10 mL blood). The A-PRF membranes dissolved in vitro after less than 3 days, while the L-PRF membrane remained in good shape during at least 7 days. Each centrifuge has its clear own profile of vibrations depending on the rotational speed, and the centrifuge characteristics are directly impacting the architecture and cell content of a L-PRF clot. This result may reveal a considerable flaw in all the PRP/PRF literature, as this parameter was never considered. The original L-PRF clot (Intra-Spin) presented very specific characteristics, which appeared distorted when using centrifuges with a higher vibration level. A-PRF, LW and Salvin centrifuges produced PRF-like materials with a damaged and almost destroyed cell population through the standard protocol, and it is therefore impossible to classify these products in the L-PRF family. Moreover, when using the same centrifuge, the original L-PRF protocol allowed producing larger clots/membranes and a more intense release of growth factors (biological signature at least twice stronger) than the modified A-PRF protocol. Both protocols are therefore significantly different, and the clinical and experimental results from the original L-PRF shall not be extrapolated to the A-PRF. Finally, the comparison between the total released amounts and the initial content of the membrane (after forcible extraction) highlighted that the leukocytes living in the fibrin matrix are involved in the production of significant amounts of growth factors. The centrifuge characteristics and centrifugation protocols impact significantly and dramatically the cells, growth factors and fibrin architecture of L-PRF.

Last 20 aa of the West Nile virus NS1' protein are responsible for its retention in cells and the formation of unique heat-stable dimers.

PubMed

Young, Lucy B; Melian, Ezequiel Balmori; Setoh, Yin Xiang; Young, Paul R; Khromykh, Alexander A

2015-05-01

West Nile virus (WNV), a mosquito-borne flavivirus, is the major cause of arboviral encephalitis in the USA. As with other members of the Japanese encephalitis virus serogroup, WNV produces an additional non-structural protein, NS1', a C-terminal extended product of NS1 generated as the result of a -1 programmed ribosomal frameshift (PRF). We have previously shown that mutations abolishing the PRF, and consequently NS1', resulted in reduced neuroinvasiveness. However, whether this was caused by the PRF event itself or by the lack of a PRF product, NS1', or a combination of both, remains undetermined. Here, we showed that WNV NS1' formed a unique subpopulation of heat- and low-pH-stable dimers. C-terminal truncations and mutational analysis employing an NS1'-expressing plasmid showed that stability of NS1' dimers was linked to the penultimate 10 aa. To examine the role of NS1' heat-stable dimers in virus replication and pathogenicity, a stop codon mutation was introduced into NS1' to create a WNV producing a truncated version of NS1' lacking the last 20 aa, but not affecting the PRF. NS1' protein produced by this mutant virus was secreted more efficiently than WT NS1', indicating that the sequence of the last 20 aa of NS1' was responsible for its cellular retention. Further analysis of this mutant showed growth kinetics in cells and virulence in weanling mice after peripheral infection similar to the WT WNVKUN, suggesting that full-length NS1' was not essential for virus replication in vitro and for virulence in mice. © 2015 The Authors.

Characterization of peripheral and central sensitization after dorsal root ganglion intervention in patients with unilateral lumbosacral radicular pain: a prospective pilot study.

PubMed

Mehta, V; Snidvongs, S; Ghai, B; Langford, R; Wodehouse, T

2017-06-01

Quantitative sensory testing (QST) has been used to predict the outcome of epidural steroid injections in lumbosacral radicular pain and has the potential to be an important tool in the selection of appropriate treatment (such as epidural steroid injections vs surgery) for patients with chronic radicular pain. In addition, QST assists in identification of the pain pathways of peripheral and central sensitization in selected groups of patients. Twenty-three patients were given dorsal root ganglion (DRG) infiltration with local anaesthesia and steroid ('DRG block'), and those who demonstrated at least 50% pain relief were offered pulsed radiofrequency (PRF) to the DRG. Questionnaires and QST scores were measured before the DRG blocks and at 1 week and 3 months after their procedure. Those who received PRF also answered questionnaires and underwent QST measurements at 1 week and 3 months after their procedure. There was a significant increase in pressure pain threshold scores after DRG blocks. A reduced conditioned pain modulation response was seen before DRG, which increased after the procedure. Ten out of 23 patients underwent PRF to the DRG, and an increase in pressure pain threshold scores after PRF was observed. The conditioned pain modulation response was maintained in this group and increased after PRF. The study demonstrates that patients with unilateral radicular low back pain who receive dorsal root ganglion interventions show changes in pressure pain thresholds and conditioned pain modulation that are consistent with a 'normalization' of peripheral and central sensitization. © The Author 2017. Published by Oxford University Press on behalf of the British Journal of Anaesthesia. All rights reserved. For Permissions, please email: journals.permissions@oup.com

A New Method to Develop Human Dental Pulp Cells and Platelet-rich Fibrin Complex.

PubMed

He, Xuan; Chen, Wen-Xia; Ban, Guifei; Wei, Wei; Zhou, Jun; Chen, Wen-Jin; Li, Xian-Yu

2016-11-01

Platelet-rich fibrin (PRF) has been used as a scaffold material in various tissue regeneration studies. In the previous methods to combine seed cells with PRF, the structure of PRF was damaged, and the manipulation time in vitro was also increased. The objective of this in vitro study was to explore an appropriate method to develop a PRF-human dental pulp cell (hDPC) complex to maintain PRF structure integrity and to find out the most efficient part of PRF. The PRF-hDPC complex was developed at 3 different time points during PRF preparation: (1) the before centrifugation (BC) group, the hDPC suspension was added to the venous blood before blood centrifugation; (2) the immediately after centrifugation (IAC) group, the hDPC suspension was added immediately after blood centrifugation; (3) the after centrifugation (AC) group, the hDPC suspension was added 10 minutes after blood centrifugation; and (4) the control group, PRF without hDPC suspension. The prepared PRF-hDPC complexes were cultured for 7 days. The samples were fixed for histologic, immunohistochemistry, and scanning electron microscopic evaluation. Real-time polymerase chain reaction was performed to evaluate messenger RNA expression of alkaline phosphatase and dentin sialophosphoprotein. Enzyme-linked immunosorbent assay quantification for growth factors was performed within the different parts of the PRF. Histologic, immunohistochemistry, and scanning electron microscopic results revealed that hDPCs were only found in the BC group and exhibited favorable proliferation. Real-time polymerase chain reaction revealed that alkaline phosphatase and dentin sialophosphoprotein expression increased in the cultured PRF-hDPC complex. The lower part of the PRF released the maximum quantity of growth factors. Our new method to develop a PRF-hDPCs complex maintained PRF structure integrity. The hDPCs were distributed in the buffy coat, which might be the most efficient part of PRF. Copyright © 2016 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

Potential for Osseous Regeneration of Platelet-Rich Fibrin-A Comparative Study in Mandibular Third Molar Impaction Sockets.

PubMed

Varghese, Mathew P; Manuel, Suvy; Kumar L K, Surej

2017-07-01

This study investigated the potential of platelet-rich fibrin (PRF) for osseous regeneration and soft tissue healing in mandibular third molar impaction sockets. A prospective in vivo study was performed. Randomization was performed after extraction. On one side, the socket was sutured primarily (control site); on the other side, autologous PRF gel was placed and then the socket was sutured (test site). Postoperatively, grid periapical radiographs were obtained at periodic intervals (weeks 1, 4, and 16) and digitalized. Gray-level values were measured at 3 different regions of the socket (for regions of newly formed bone) compared with the natural bone area using HL Image++ software, and the percentage bone fill was measured. Clinical evaluation of soft tissue healing was performed using the healing index of Landry et al (J Periodontol 60:212, 1994) at the specific intervals. Thirty healthy men and women (age range, 18 to 35 yr) with bilaterally impacted mandibular third molars were enrolled in this study. In general, there was markedly greater bone formation in sockets treated with PRF (P < .05). In the PRF group, the average gray-level values at the cervical, middle, and apical regions were 61.85 (standard deviation [SD], ±25.186), 64.54 (SD, ±24.831), and 67.80 (SD, ±23.946), respectively, with a mean value of 64.73 (SD, ±24.411). In the control group, these values were 51.58 (SD, ±15.286), 54.30 (SD, ±16.274), and 57.53 (SD, ±16.187), respectively, with a mean of 53.67 (SD, ±16.528). The average percentage of bone fill in the PRF group was 57.90 (SD, ±26.789) and that of the non-PRF group was 46.74 (SD, ±17.713; P < .05). Soft tissue healing as evaluated by the healing index of Landry et al also was found to be better at the PRF test site and it was statistically significant (P < .05). There was evidence for better osseous regeneration and soft tissue healing in response to PRF. Further investigations to evaluate the application of PRF in other areas of oral and maxillofacial surgery are imperative. Copyright © 2017 American Association of Oral and Maxillofacial Surgeons. Published by Elsevier Inc. All rights reserved.

HMBPP-deficient Listeria mutant immunization alters pulmonary/systemic responses, effector functions, and memory polarization of Vγ2Vδ2 T cells

PubMed Central

Frencher, James T.; Shen, Hongbo; Yan, Lin; Wilson, Jessica O.; Freitag, Nancy E.; Rizzo, Alicia N.; Chen, Crystal Y.; Chen, Zheng W.

2014-01-01

Whereas infection or immunization of humans/primates with microbes coproducing HMBPP/IPP can remarkably activate Vγ2Vδ2 T cells, in vivo studies have not been done to dissect HMBPP- and IPP-driven expansion, pulmonary trafficking, effector functions, and memory polarization of Vγ2Vδ2 T cells. We define these phosphoantigen-host interplays by comparative immunizations of macaques with the HMBPP/IPP-coproducing Listeria ΔactA prfA* and HMBPP-deficient Listeria ΔactAΔgcpE prfA* mutant. The HMBPP-deficient ΔgcpE mutant shows lower ability to expand Vγ2Vδ2 T cells in vitro than the parental HMBPP-producing strain but displays comparably attenuated infectivity or immunogenicity. Respiratory immunization of macaques with the HMBPP-deficient mutant elicits lower pulmonary and systemic responses of Vγ2Vδ2 T cells compared with the HMBPP-producing vaccine strain. Interestingly, HMBPP-deficient mutant reimmunization or boosting elicits enhanced responses of Vγ2Vδ2 T cells, but the magnitude is lower than that by HMBPP-producing listeria. HMBPP-deficient listeria differentiated fewer Vγ2Vδ2 T effector cells capable of coproducing IFN-γ and TNF-α and inhibiting intracellular listeria than HMBPP-producing listeria. Furthermore, HMBPP deficiency in listerial immunization influences memory polarization of Vγ2Vδ2 T cells. Thus, both HMBPP and IPP production in listerial immunization or infection elicit systemic/pulmonary responses and differentiation of Vγ2Vδ2 T cells, but a role for HMBPP is more dominant. Findings may help devise immune intervention. PMID:25114162

Integrative Genomic Analysis Identifies Isoleucine and CodY as Regulators of Listeria monocytogenes Virulence

PubMed Central

Lobel, Lior; Sigal, Nadejda; Borovok, Ilya; Ruppin, Eytan; Herskovits, Anat A.

2012-01-01

Intracellular bacterial pathogens are metabolically adapted to grow within mammalian cells. While these adaptations are fundamental to the ability to cause disease, we know little about the relationship between the pathogen's metabolism and virulence. Here we used an integrative Metabolic Analysis Tool that combines transcriptome data with genome-scale metabolic models to define the metabolic requirements of Listeria monocytogenes during infection. Twelve metabolic pathways were identified as differentially active during L. monocytogenes growth in macrophage cells. Intracellular replication requires de novo synthesis of histidine, arginine, purine, and branch chain amino acids (BCAAs), as well as catabolism of L-rhamnose and glycerol. The importance of each metabolic pathway during infection was confirmed by generation of gene knockout mutants in the respective pathways. Next, we investigated the association of these metabolic requirements in the regulation of L. monocytogenes virulence. Here we show that limiting BCAA concentrations, primarily isoleucine, results in robust induction of the master virulence activator gene, prfA, and the PrfA-regulated genes. This response was specific and required the nutrient responsive regulator CodY, which is known to bind isoleucine. Further analysis demonstrated that CodY is involved in prfA regulation, playing a role in prfA activation under limiting conditions of BCAAs. This study evidences an additional regulatory mechanism underlying L. monocytogenes virulence, placing CodY at the crossroads of metabolism and virulence. PMID:22969433

Identification of Novel Listeria monocytogenes Secreted Virulence Factors following Mutational Activation of the Central Virulence Regulator, PrfA▿ †

PubMed Central

Port, Gary C.; Freitag, Nancy E.

2007-01-01

Upon bacterial entry into the cytosol of infected mammalian host cells, the central virulence regulator PrfA of Listeria monocytogenes becomes activated and induces the expression of numerous factors which contribute to bacterial pathogenesis. The mechanism or signal by which PrfA becomes activated during the course of infection has not yet been determined; however, several amino acid substitutions within PrfA (known as PrfA* mutations) that appear to lock the protein into a constitutively activated state have been identified. In this study, the PrfA activation statuses of several L. monocytogenes mutant strains were subjected to direct isogenic comparison and the mutant with the highest activity, the prfA(L140F) mutant, was identified. The prfA(L140F) strain was subsequently used as a tool to identify gene products secreted as a result of PrfA activation. By use of two-dimensional gel electrophoresis followed by liquid chromatography-electrospray ionization-tandem mass spectroscopy analyses, 15 proteins were identified as up-regulated in the prfA(L140F) secretome, while the secretion of two proteins was found to be reduced. Although some of the proteins identified were known to be subject to direct regulation by PrfA, the majority have not previously been associated with PrfA regulation and their expression or secretion may be influenced indirectly by a PrfA-dependent regulatory pathway. Plasmid insertion inactivation of the genes encoding four novel secreted products indicated that three of the four have significant roles in L. monocytogenes virulence. The use of mutationally activated prfA alleles therefore provides a useful approach towards identifying gene products that contribute to L. monocytogenes pathogenesis. PMID:17938228

Impact of preoperative calculation of nephron volume loss on future of partial nephrectomy techniques; planning a strategic roadmap for improving functional preservation and securing oncological safety.

PubMed

Rha, Koon H; Abdel Raheem, Ali; Park, Sung Y; Kim, Kwang H; Kim, Hyung J; Koo, Kyo C; Choi, Young D; Jung, Byung H; Lee, Sang K; Lee, Won K; Krishnan, Jayram; Shin, Tae Y; Cho, Jin-Seon

2017-11-01

To assess the correlation of the resected and ischaemic volume (RAIV), which is a preoperatively calculated volume of nephron loss, with the amount of postoperative renal function (PRF) decline after minimally invasive partial nephrectomy (PN) in a multi-institutional dataset. We identified 348 patients from March 2005 to December 2013 at six institutions. Data on all cases of laparoscopic (n = 85) and robot-assisted PN (n = 263) performed were retrospectively gathered. Univariable and multivariable linear regression analyses were used to identify the associations between various time points of PRF and the RAIV, as a continuous variable. The mean (sd) RAIV was 24.2 (29.2) cm 3 . The mean preoperative estimated glomerular filtration rate (eGFR) and the eGFRs at postoperative day 1, 6 and 36 months after PN were 91.0 and 76.8, 80.2 and 87.7 mL/min/1.73 m 2 , respectively. In multivariable linear regression analysis, the amount of decline in PRF at follow-up was significantly correlated with the RAIV (β 0.261, 0.165, 0.260 at postoperative day 1, 6 and 36 months after PN, respectively). This study has the limitation of its retrospective nature. Preoperatively calculated RAIV significantly correlates with the amount of decline in PRF during long-term follow-up. The RAIV could lead our research to the level of prediction of the amount of PRF decline after PN and thus would be appropriate for assessing the technical advantages of emerging techniques. © 2017 The Authors BJU International © 2017 BJU International Published by John Wiley & Sons Ltd.

Scintigraphic evaluation of osteoblastic activity in extraction sockets treated with platelet-rich fibrin.

PubMed

Gürbüzer, Bahadir; Pikdöken, Levent; Tunali, Mustafa; Urhan, Muammer; Küçükodaci, Zafer; Ercan, Feriha

2010-05-01

To evaluate the effect of platelet-rich fibrin (PRF) on the early bone healing process with bone scintigraphy based on technetium-99m methylene diphosphonate uptake in third molar extraction sockets. Fourteen patients with bilaterally soft tissue impacted third mandibular molars were included in the study. The right and left impacted third molars were surgically extracted in the same session. PRF was randomly administered into one of the extraction sockets, whereas the contralateral sockets were left without treatment. Four weeks after surgery, scintigrams were obtained to evaluate scintigraphic differences between PRF-treated and non-PRF-treated sockets. After completion of the clinical study, PRF samples were evaluated by light and scanning electron microscopy. The average increase in technetium-99m methylene diphosphonate uptake as an indication of enhanced bone healing did not differ significantly between PRF-treated and non-PRF-treated sockets 4 weeks postoperatively (P > .05). Abundant fibrin and inflammatory cells were observed by light microscopic examination of PRF samples. Scanning electron microscopic analysis of PRF revealed the existence of platelet aggregates in a fibrin network and crystalline particles on the outer surface of PRF. PRF might not lead to enhanced bone healing in soft tissue impacted mandibular third molar extraction sockets 4 weeks after surgery. PRF exhibits the potential characteristics of an autologous fibrin matrix. However, whether the presence of crystal-like particles on the outer surface of PRF alters bone healing should be investigated further. Copyright 2010 American Association of Oral and Maxillofacial Surgeons. Published by Elsevier Inc. All rights reserved.

Osteoblastic mesenchymal stem cell sheet combined with Choukroun platelet-rich fibrin induces bone formation at an ectopic site.

PubMed

Wang, Zhifa; Weng, Yanming; Lu, Shengjun; Zong, Chunlin; Qiu, Jianyong; Liu, Yanpu; Liu, Bin

2015-08-01

To analyze the effects of platelet-rich fibrin (PRF) on mesenchymal stem cells (MSCs) in vitro and investigate in vivo bone formation by MSC sheets with PRF. Cell proliferation and expression of osteogenesis-related genes within MSC sheets were assessed upon exposure to PRF from the same donors. We then injected MSC sheet fragments with or without PRF subcutaneously in nude mice and assessed bone formation by micro-computed tomography and histological analyses. PRF significantly stimulated MSC proliferation and osteogenesis in vitro. MSC sheets injected with or without PRF formed new bone, but those with PRF produced significantly more and denser bone. MSC sheets can be used to generate tissue engineered bone upon injection, and PRF increases the osteogenic capacity of MSC sheets in vitro and in vivo. © 2014 Wiley Periodicals, Inc.

In vivo evaluation of titanium-prepared platelet-rich fibrin (T-PRF): a new platelet concentrate.

PubMed

Tunalı, Mustafa; Özdemir, Hakan; Küçükodacı, Zafer; Akman, Serhan; Fıratlı, Erhan

2013-07-01

We have developed a new, titanium-prepared, platelet-rich fibrin (T-PRF) together with the protocol for forming it, which is based on the hypothesis that titanium tubes may be more effective at activating platelets than the glass tubes used by Chouckroun in his platelet-rich fibrin (PRF) method. The aim of this study was to find a suitable animal model in which to evaluate the method and to investigate the efficacy of T-PRF for wound healing. Blood samples from 6 rabbits were used to confirm the protocol for formation of T-PRF. We evaluated T-PRF or T-PRF-like clots morphologically using scanning electron microscopy (EM). Blood samples from 5 rabbits were used to develop an experiment in which to evaluate the effects of T-PRF on wound healing. The mucoperiosteal flaps were filled with autologous T-PRF membranes from the vestibule in the anterior mandibular regions. Samples collected from the surgical sites were stained with haematoxylin and eosin. We found a mature fibrin network in T-PRF clots that had been centrifuged for 15 min at 3500 rpm and, 15 days after placement of the membrane, we found newly-forming connective tissue and islets of bony tissue in the T-PRF membrane. These results show that T-PRF could induce the formation of new bone with new connective tissue in a rabbit model of wound healing within 30 days of treatment. Published by Elsevier Ltd.

Integrated Analyses of Gene Expression Profiles Digs out Common Markers for Rheumatic Diseases

PubMed Central

Wang, Lan; Wu, Long-Fei; Lu, Xin; Mo, Xing-Bo; Tang, Zai-Xiang; Lei, Shu-Feng; Deng, Fei-Yan

2015-01-01

Objective Rheumatic diseases have some common symptoms. Extensive gene expression studies, accumulated thus far, have successfully identified signature molecules for each rheumatic disease, individually. However, whether there exist shared factors across rheumatic diseases has yet to be tested. Methods We collected and utilized 6 public microarray datasets covering 4 types of representative rheumatic diseases including rheumatoid arthritis, systemic lupus erythematosus, ankylosing spondylitis, and osteoarthritis. Then we detected overlaps of differentially expressed genes across datasets and performed a meta-analysis aiming at identifying common differentially expressed genes that discriminate between pathological cases and normal controls. To further gain insights into the functions of the identified common differentially expressed genes, we conducted gene ontology enrichment analysis and protein-protein interaction analysis. Results We identified a total of eight differentially expressed genes (TNFSF10, CX3CR1, LY96, TLR5, TXN, TIA1, PRKCH, PRF1), each associated with at least 3 of the 4 studied rheumatic diseases. Meta-analysis warranted the significance of the eight genes and highlighted the general significance of four genes (CX3CR1, LY96, TLR5, and PRF1). Protein-protein interaction and gene ontology enrichment analyses indicated that the eight genes interact with each other to exert functions related to immune response and immune regulation. Conclusion The findings support that there exist common factors underlying rheumatic diseases. For rheumatoid arthritis, systemic lupus erythematosus, ankylosing spondylitis and osteoarthritis diseases, those common factors include TNFSF10, CX3CR1, LY96, TLR5, TXN, TIA1, PRKCH, and PRF1. In-depth studies on these common factors may provide keys to understanding the pathogenesis and developing intervention strategies for rheumatic diseases. PMID:26352601

Internal-Specific Morphological Analysis of Sciatic Nerve Fibers in a Radiofrequency-Induced Animal Neuropathic Pain Model

PubMed Central

Choi, Samjin; Choi, Hyuk Jai; Cheong, Youjin; Lim, Young-Jin; Park, Hun-Kuk

2013-01-01

This study investigated the reversible effects of pulsed radiofrequency (PRF) treatment at 42°C on the ultrastructural and biological changes in nerve and collagen fibers in the progression of neuropathic pain after rat sciatic nerve injury. Assessments of morphological changes in the extracellular matrices by atomic force microscopy and hematoxylin-eosin, Masson’s trichrome and picrosirius-red staining as well as the expressions of two fibril-forming collagens, types-I and -III, and two inflammatory cytokines, TNF-α and IL-6, were evaluated on day 30 after RF exposure. There were four groups for different RF thermal treatments: no treatment, no current, PRF, and continuous RF (CRF). An RF procedure similar to that used in human clinical trials was used in this study. The CRF treatment at 82°C led to neural and collagen damage by the permanent blockage of sensory nociceptors. The PRF treatment led to excellent performance and high expandability compared to CRF, with effects including slight damage and swelling of myelinated axons, a slightly decreased amount of collagen fibers, swelling of collagen fibril diameters, decreased immunoreactivity of collagen types-I and -III, presence of newly synthesized collagen, and recovery of inflammatory protein immunoreactivity. These evidence-based findings suggest that PRF-based pain relief is responsible for the temporary blockage of nerve signals as well as the preferential destruction of pain-related principal sensory fibers like the Aδ and C fibers. This suggestion can be supported by the interaction between the PRF-induced electromagnetic field and cell membranes; therefore, PRF treatment provides pain relief while allowing retention of some tactile sensation. PMID:24066083

Platelet-Rich Fibrin Promotes an Accelerated Healing of Achilles Tendon When Compared to Platelet-Rich Plasma in Rat

PubMed Central

Dietrich, Franciele; L. Duré, Gustavo; P. Klein, Caroline; F. Bampi, Vinícius; V. Padoin, Alexandre; D. Silva, Vinícius; Braga-Silva, Jefferson

2015-01-01

BACKGROUND Autologous platelet concentrate has been used to improve the function and regeneration of injured tissues. Tendinopathies are common in clinical practice, although long-term treatment is required. On the basis of lead time, we compared the effect of using platelet-rich plasma (PRP) and platelet-rich fibrin (PRF) in repairing rat Achilles tendon. METHODS The effectiveness of using PRP and PRF was evaluated after 14 and 28 postoperative days by histological analysis. The quantification of collagen types I and III was performed by Sirius red staining. Qualitatively, the data were verified with hematoxylin-eosin (H&E) staining. RESULTS In Sirius red staining, no significant treatment differences were found between groups. Statistical difference was observed only between PRP (37.2% collagen) and the control group (16.2%) 14 days after treatment. Intra-groups compared twice showed a difference for collagen I (27.8% and 47.7%) and III (66.9% and 46.0%) in the PRF group. The control group showed differences only in collagen I (14.2% and 40.9%) and no other finding was observed in the PRP group. In H&E staining, PRF showed a better cellular organization when compared to the other groups at 28 days. CONCLUSION Our study suggests that PRF promotes accelerated regeneration of the Achilles tendon in rats, offering promising prospects for future clinical use. PMID:26284178

Cortical connective field estimates from resting state fMRI activity.

PubMed

Gravel, Nicolás; Harvey, Ben; Nordhjem, Barbara; Haak, Koen V; Dumoulin, Serge O; Renken, Remco; Curčić-Blake, Branislava; Cornelissen, Frans W

2014-01-01

One way to study connectivity in visual cortical areas is by examining spontaneous neural activity. In the absence of visual input, such activity remains shaped by the underlying neural architecture and, presumably, may still reflect visuotopic organization. Here, we applied population connective field (CF) modeling to estimate the spatial profile of functional connectivity in the early visual cortex during resting state functional magnetic resonance imaging (RS-fMRI). This model-based analysis estimates the spatial integration between blood-oxygen level dependent (BOLD) signals in distinct cortical visual field maps using fMRI. Just as population receptive field (pRF) mapping predicts the collective neural activity in a voxel as a function of response selectivity to stimulus position in visual space, CF modeling predicts the activity of voxels in one visual area as a function of the aggregate activity in voxels in another visual area. In combination with pRF mapping, CF locations on the cortical surface can be interpreted in visual space, thus enabling reconstruction of visuotopic maps from resting state data. We demonstrate that V1 ➤ V2 and V1 ➤ V3 CF maps estimated from resting state fMRI data show visuotopic organization. Therefore, we conclude that-despite some variability in CF estimates between RS scans-neural properties such as CF maps and CF size can be derived from resting state data.

Leucocyte-rich and platelet-rich fibrin for the treatment of bisphosphonate-related osteonecrosis of the jaw: a prospective feasibility study.

PubMed

Kim, Jin-Woo; Kim, Sun-Jong; Kim, Myung-Rae

2014-11-01

Our aim was to assess the feasibility of using leucocyte-rich and platelet-rich fibrin (L-PRF) for the treatment of bisphosphonate-related osteonecrosis of the jaw (BRONJ) in a single group study. After treatment with L-PRF, the response of each patient was recorded 1 month and 4 months postoperatively. Further assessments were made of the site, stage, concentration of c-terminal crosslinked telopepide of type 1 collagen, and actinomycosis. Among the total of 34 patients, 26 (77%) showed complete resolution, 6 (18%) had delayed resolution, and 2 (6%) showed no resolution. There was a significant association between the response to treatment and the stage of BRONJ (p=0.002) but no other significant associations were detected. This study has shown that it is feasible to use L-PRF for the treatment of BRONJ, but the effectiveness cannot be judged with this study design. Randomised prospective trials are needed to confirm this. Copyright © 2014 The British Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.

The effect of platelet-rich fibrin on implant stability.

PubMed

Öncü, Elif; Alaaddinoğlu, E Emine

2015-01-01

Achieving accelerated implant osseointegration could make immediate or early loading of implants more predictable. Platelet-rich fibrin (PRF) is frequently used to accelerate soft and hard tissue healing. The activated platelets in PRF release growth factors, resulting in cellular proliferation, collagen synthesis, and osteoid production. The aim of this study was to compare the stability of dental implants inserted in a one-stage surgical protocol with or without PRF application. Twenty healthy patients with adequate alveolar bone and two or more adjacent missing teeth extracted at least 6 months previously were included in this study. A minimum of two tapered implants (Ankylos, Dentsply/Friadent) were placed in each patient. After surgical preparation of the implant sockets, PRF that had been prepared preoperatively was placed randomly into one of the sockets (PRF+). The acellular plasma portion of PRF was used to wet the implant placed into the PRF-coated socket. Resonance frequency measurements were made after implant placement and at 1 week and 1 month postoperatively. Mean implant stability quotients (ISQs) of the PRF+ implants was 69.3 ± 10.5, and mean ISQs for the PRF- implants was 64.5 ± 12.2 at the end of the first week. The mean ISQs at 4 weeks postoperatively were 77.1 ± 7.1 for the PRF+ group and 70.5 ± 7.7 for the PRF- group. In this study, PRF application increased implant stability during the early healing period, as evidenced by higher ISQ values. Simple application of this material seems to provide faster osseointegration.

Platelet Rich Fibrin (P.R.F.) in Reconstructive Surgery of Atrophied Maxillary Bones: Clinical and Histological Evaluations

PubMed Central

Tatullo, Marco; Marrelli, Massimo; Cassetta, Michele; Pacifici, Andrea; Stefanelli, Luigi Vito; Scacco, Salvatore; Dipalma, Gianna; Pacifici, Luciano; Inchingolo, Francesco

2012-01-01

Introduction. Maxillary bone losses often require additional regenerative procedures: as a supplement to the procedures of tissue regeneration, a platelet concentrate called PRF (Platelet Rich Fibrin) was tested for the first time in France by Dr. Choukroun. Aim of the present study is to investigate, clinically and histologically, the potential use of PRF, associated with deproteinized bovine bone (Bio-Oss), as grafting materials in pre-implantology sinus grafting of severe maxillary atrophy, in comparison with a control group, in which only deproteinized bovine bone (Bio-Oss) was used as reconstructive material. Materials and Methods. 60 patients were recruited using the cluster-sampling method; inclusion criteria were maxillary atrophy with residual ridge < 5mm. The major atrophies in selected patients involved sinus-lift, with a second-look reopening for the implant insertion phase. The used grafting materials were: a) Bio-Oss and b) amorphous and membranous PRF together with Bio-Oss. We performed all operations by means of piezosurgery in order to reduce trauma and to optimize the design of the operculum on the cortical bone. The reopening of the surgical area was scheduled at 3 different times. Results. 72 sinus lifts were performed with subsequent implants insertions. We want to underline how the histological results proved that the samples collected after 106 days (Early protocol) with the adding of PRF were constituted by lamellar bone tissue with an interposed stroma that appeared relaxed and richly vascularized. Conclusions. The use of PRF and piezosurgery reduced the healing time, compared to the 150 days described in literature, favoring optimal bone regeneration. At 106 days, it is already possible to achieve good primary stability of endosseous implants, though lacking of functional loading. PMID:23155361

AIDPRF/PRFAID user's manual

NASA Technical Reports Server (NTRS)

Buck, C. H.

1975-01-01

The program documentation for the PRF ARTWORK/AIDS conversion program, which serves as the interface between the outputs of the PRF ARTWORK and AIDS programs, was presented. The document has a two-fold purpose, the first of which is a description of the software design including flowcharts of the design at the functional level. The second purpose is to provide the user with a detailed description of the input parameters and formats necessary to execute the program and a description of the output produced when the program is executed.

A comprehensive review of pulsed radiofrequency in the treatment of pain associated with different spinal conditions

PubMed Central

Facchini, Giancarlo; Spinnato, Paolo; Guglielmi, Giuseppe; Bazzocchi, Alberto

2017-01-01

Objective: The objective of this review was to evaluate the efficacy of pulsed radiofrequency (PRF) treatment of pain associated with different spinal conditions. The mechanisms of action and biological effects are shortly discussed to provide the scientific basis for this radiofrequency modality. Methods: We systematically searched for clinical studies on spinal clinical conditions using PRF. We searched the MEDLINE (PubMed) database. We classified the information in one table focusing on randomized controlled trials (RCTs) and other types of studies. Date of last electronic search was October 2016. Results: We found four RCTs that evaluated the efficacy of PRF on cervical radicular pain and five observational studies. Two trials and three observational studies were conducted in patients with facet pain. For disc-related pathology, we found one RCT with PRF applied intradiscally and three RCTs for dorsal root ganglia PRF modulation lumbosacral radicular pain. For sacroiliac joint pain, spondylolisthesis, malignancies and other minor spinal pathology, limited studies were conducted. Conclusion: From the available evidence, the use of PRF to the dorsal root ganglion in cervical radicular pain is compelling. With regard to its lumbosacral counterpart, the use of PRF cannot be similarly advocated in view of the absence of standardization of PRF parameters, enrolment criteria and different methods in reporting results; but, the evidence is interesting. The use of PRF in lumbar facet pain was found to be less effective than conventional RF techniques. For the other different spinal conditions, we need further studies to assess the effectiveness of PRF. Advances in knowledge: The use of PRF in lumbar facet pain was found to be less effective than conventional RF techniques. For the other different spinal conditions, we need further studies to assess the effectiveness of PRF. PMID:28186832

SECEC Research Grant 2008 II: Use of platelet- and leucocyte-rich fibrin (L-PRF) does not affect late rotator cuff tendon healing: a prospective randomized controlled study.

PubMed

Zumstein, Matthias A; Rumian, Adam; Thélu, Charles Édouard; Lesbats, Virginie; O'Shea, Kieran; Schaer, Michael; Boileau, Pascal

2016-01-01

Because the retear rate after rotator cuff repairs remains high, methods to improve healing are very much needed. Platelet-rich concentrates have been shown to enhance tenocyte proliferation and promote extracellular matrix synthesis in vitro; however, their clinical benefit remains unclear. We hypothesized that arthroscopic rotator cuff repair with leucocyte- and platelet-rich fibrin (L-PRF) results in better clinical and radiographic outcome at 12 months of follow-up than without L-PRF. Thirty-five patients were randomized to receive arthroscopic rotator cuff repair with L-PRF locally applied to the repair site (L-PRF+ group, n = 17) or without L-PRF (L-PRF- group, n = 18). Preoperative and postoperative clinical evaluation included the Subjective Shoulder Value, visual analog score for pain, Simple Shoulder Test, and Constant-Murley score. The anatomic watertight healing, tendon thickness, and tendon quality was evaluated using magnetic resonance arthrography at 12 months of follow-up. No complications were reported in either group. The mean Subjective Shoulder Value, Simple Shoulder Test, and Constant-Murley scores increased from preoperatively to postoperatively, showing no significant differences between the groups. Complete anatomic watertight healing was found in 11 of 17 in the L-PRF+ group and in 11 of 18 in the L-PRP- group (P = .73). The mean postoperative defect size (214 ± 130 mm(2) in the L-PRF+ group vs 161 ± 149 mm(2) in the L-PRF- group; P = .391) and the mean postoperative tendon quality according to Sugaya (L-PRF+ group: 3.0 ± 1.4, L-PRF- group: 3.0 ± 0.9) were similar in both groups at 12 months of follow-up. Arthroscopic rotator cuff repair with application of L-PRF yields no beneficial effect in clinical outcome, anatomic healing rate, mean postoperative defect size, and tendon quality at 12 months of follow-up. Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.

The virulence regulator PrfA promotes biofilm formation by Listeria monocytogenes.

PubMed

Lemon, Katherine P; Freitag, Nancy E; Kolter, Roberto

2010-08-01

Listeria monocytogenes is a food-borne facultative intracellular pathogen. It is widespread in the environment and has several distinct life-styles. The key transcriptional activator PrfA positively regulates L. monocytogenes virulence genes to mediate the transition from extracellular, flagellum-propelled cell to intracellular pathogen. Here we report the first evidence that PrfA also has a significant positive impact on extracellular biofilm formation. Mutants lacking prfA were defective in surface-adhered biofilm formation. The DeltaprfA mutant exhibited wild-type flagellar motility, and its biofilm defect occurred after initial surface adhesion. We also observed that mutations that led to the constitutive expression of PrfA-dependent virulence genes had a minimal impact on biofilm formation. Furthermore, biofilm development was enhanced in a mutant encoding a PrfA protein variant unable to fully transition from the extracellular form to the virulent, intracellular activity conformation. These results indicate that PrfA positively regulates biofilm formation and suggest that PrfA has a global role in modulating the life-style of L. monocytogenes. The requirement of PrfA for optimal biofilm formation may provide selective pressure to maintain this critical virulence regulator when L. monocytogenes is outside host cells in the environment.

The heat-compression technique for the conversion of platelet-rich fibrin preparation to a barrier membrane with a reduced rate of biodegradation.

PubMed

Kawase, Tomoyuki; Kamiya, Mana; Kobayashi, Mito; Tanaka, Takaaki; Okuda, Kazuhiro; Wolff, Larry F; Yoshie, Hiromasa

2015-05-01

Platelet-rich fibrin (PRF) was developed as an advanced form of platelet-rich plasma to eliminate xenofactors, such as bovine thrombin, and it is mainly used as a source of growth factor for tissue regeneration. Furthermore, although a minor application, PRF in a compressed membrane-like form has also been used as a substitute for commercially available barrier membranes in guided-tissue regeneration (GTR) treatment. However, the PRF membrane is resorbed within 2 weeks or less at implantation sites; therefore, it can barely maintain sufficient space for bone regeneration. In this study, we developed and optimized a heat-compression technique and tested the feasibility of the resulting PRF membrane. Freshly prepared human PRF was first compressed with dry gauze and subsequently with a hot iron. Biodegradability was microscopically examined in vitro by treatment with plasmin at 37°C or in vivo by subcutaneous implantation in nude mice. Compared with the control gauze-compressed PRF, the heat-compressed PRF appeared plasmin-resistant and remained stable for longer than 10 days in vitro. Additionally, in animal implantation studies, the heat-compressed PRF was observed at least for 3 weeks postimplantation in vivo whereas the control PRF was completely resorbed within 2 weeks. Therefore, these findings suggest that the heat-compression technique reduces the rate of biodegradation of the PRF membrane without sacrificing its biocompatibility and that the heat-compressed PRF membrane easily could be prepared at chair-side and applied as a barrier membrane in the GTR treatment. © 2014 Wiley Periodicals, Inc.

Pulsed radiofrequency for occipital neuralgia.

PubMed

Manolitsis, Nicholas; Elahi, Foad

2014-01-01

The clinical application of pulsed radiofrequency (PRF) by interventional pain physicians for a variety of chronic pain syndromes, including occipital neuralgia, is growing. As a minimally invasive percutaneous technique with none to minimal neurodestruction and a favorable side effect profile, use of PRF as an interventional neuromodulatory chronic pain treatment is appealing. Occipital neuralgia, also known as Arnold's neuralgia, is defined by the International Headache Society as a paroxysmal, shooting or stabbing pain in the greater, lesser, and/or third occipital nerve distributions. Pain intensity is often severe and debilitating, with an associated negative impact upon quality of life and function. Most cases of occipital neuralgia are idiopathic, with no clearly identifiable structural etiology. Treatment of occipital neuralgia poses inherent challenges as no criterion standard exists. Initially, conservative treatment options such as physical therapy and pharmacotherapy are routinely trialed. When occipital neuralgia is refractory to conservative measures, a number of interventional treatment options exist, including: local occipital nerve anesthetic and corticosteroid infiltration, botulinum toxin A injection, occipital nerve subcutaneous neurostimulation, and occipital nerve PRF. Of these, PRF has garnered significant interest as a potentially superior, safe, non-invasive treatment with long-term efficacy. The objective of this article is to provide a concise review of occipital neuralgia; and a concise, yet thorough, evidence-based review of the current literature concerning the use of PRF for occipital neuralgia. Review of published medical literature up through April 2013. The Center for Pain Medicine and Regional Anesthesia, the University of Iowa Hospitals and Clinics. A total of 3 clinical studies and one case report investigating the use of PRF for knee occipital neuralgia have been published worldwide. Statistically significant improvements in pain, quality of life, and adjuvant pain medication usage have been demonstrated. Lack of randomized control trials, small study sample sizes, an absence of diagnostic block imaging guidance, and the use of outcome measures that are inherently subjective, limiting objectivity and introducing an unquantifiable degree of bias. Clinical studies to date examining the efficacy of PRF as a treatment for occipital neuralgia have yielded promising results, demonstrating sustained improvement in pain, quality of life, and adjuvant pain medication usage. Despite these encouraging clinical studies, conclusive evidence in support of PRF as an interventional treatment option for occipital neuralgia awaits to be seen.

Novel Escherichia coli RF1 mutants with decreased translation termination activity and increased sensitivity to the cytotoxic effect of the bacterial toxins Kid and RelE.

PubMed

Diago-Navarro, Elizabeth; Mora, Liliana; Buckingham, Richard H; Díaz-Orejas, Ramón; Lemonnier, Marc

2009-01-01

Novel mutations in prfA, the gene for the polypeptide release factor RF1 of Escherichia coli, were isolated using a positive genetic screen based on the parD (kis, kid) toxin-antitoxin system. This original approach allowed the direct selection of mutants with altered translational termination efficiency at UAG codons. The isolated prfA mutants displayed a approximately 10-fold decrease in UAG termination efficiency with no significant changes in RF1 stability in vivo. All three mutations, G121S, G301S and R303H, were situated close to the nonsense codon recognition site in RF1:ribosome complexes. The prfA mutants displayed increased sensitivity to the RelE toxin encoded by the relBE system of E. coli, thus providing in vivo support for the functional interaction between RF1 and RelE. The prfA mutants also showed increased sensitivity to the Kid toxin. Since this toxin can cleave RNA in a ribosome-independent manner, this result was not anticipated and provided first evidence for the involvement of RF1 in the pathway of Kid toxicity. The sensitivity of the prfA mutants to RelE and Kid was restored to normal levels upon overproduction of the wild-type RF1 protein. We discuss these results and their utility for the design of novel antibacterial strategies in the light of the recently reported structure of ribosome-bound RF1.

Socket preservation by beta-tri-calcium phosphate with collagen compared to platelet-rich fibrin: A clinico-radiographic study

PubMed Central

Das, Swati; Jhingran, Rajesh; Bains, Vivek Kumar; Madan, Rohit; Srivastava, Ruchi; Rizvi, Iram

2016-01-01

Objectives: This study was primarily designed to determine the clinico-radiographic efficacy of platelet-rich fibrin (PRF) and beta-tri-calcium phosphate with collagen (β-TCP-Cl) in preserving extraction sockets. Materials and Methods: For Group I (PRF), residual sockets (n = 15) were filled with autologous PRF obtained from patients' blood; and for Group II (β-TCP-Cl), residual sockets (n = 15) were filled with β-TCP-Cl. For the sockets randomly selected for Group II (β-TCP-Cl), the reshaped Resorbable Tissue Replacement cone was inserted into the socket. Results: Clinically, there was a significantly greater decrease in relative socket depth, but apposition in midcrestal height in Group II (β-TCP-Cl) as compared to Group I (PRF), whereas more decrease in buccolingual width of Group I (PRF) than Group II (β-TCP-Cl) after 6 months. Radiographically, the mean difference in socket height, residual ridge, and width (coronal, middle, and apical third of socket) after 6 months was higher in Group I (PRF) as compared to Group II (β-TCP-Cl). The mean density (in Hounsfield Units) at coronal, middle, and apical third of socket was higher in Group I (PRF) as compared to Group II (β-TCP-Cl). There were statistically significant apposition and resorption for Group I (PRF) whereas nonsignificant resorption and significant apposition for Group II (β-TCP-Cl) in buccal and lingual/palatal cortical plate, respectively, at 6 months on computerized tomography scan. Conclusion: The use of either autologous PRF or β-TCP-Cl was effective in socket preservation. Results obtained from PRF were almost similar to β-TCP-Cl; therefore being autologous, nonimmune, cost-effective, easily procurable regenerative biomaterial, PRF proves to be an insight into the future biofuel for regeneration. PMID:27095909

Socket preservation by beta-tri-calcium phosphate with collagen compared to platelet-rich fibrin: A clinico-radiographic study.

PubMed

Das, Swati; Jhingran, Rajesh; Bains, Vivek Kumar; Madan, Rohit; Srivastava, Ruchi; Rizvi, Iram

2016-01-01

This study was primarily designed to determine the clinico-radiographic efficacy of platelet-rich fibrin (PRF) and beta-tri-calcium phosphate with collagen (β-TCP-Cl) in preserving extraction sockets. For Group I (PRF), residual sockets (n = 15) were filled with autologous PRF obtained from patients' blood; and for Group II (β-TCP-Cl), residual sockets (n = 15) were filled with β-TCP-Cl. For the sockets randomly selected for Group II (β-TCP-Cl), the reshaped Resorbable Tissue Replacement cone was inserted into the socket. Clinically, there was a significantly greater decrease in relative socket depth, but apposition in midcrestal height in Group II (β-TCP-Cl) as compared to Group I (PRF), whereas more decrease in buccolingual width of Group I (PRF) than Group II (β-TCP-Cl) after 6 months. Radiographically, the mean difference in socket height, residual ridge, and width (coronal, middle, and apical third of socket) after 6 months was higher in Group I (PRF) as compared to Group II (β-TCP-Cl). The mean density (in Hounsfield Units) at coronal, middle, and apical third of socket was higher in Group I (PRF) as compared to Group II (β-TCP-Cl). There were statistically significant apposition and resorption for Group I (PRF) whereas nonsignificant resorption and significant apposition for Group II (β-TCP-Cl) in buccal and lingual/palatal cortical plate, respectively, at 6 months on computerized tomography scan. The use of either autologous PRF or β-TCP-Cl was effective in socket preservation. Results obtained from PRF were almost similar to β-TCP-Cl; therefore being autologous, nonimmune, cost-effective, easily procurable regenerative biomaterial, PRF proves to be an insight into the future biofuel for regeneration.

Local Application of Platelet-Rich Fibrin During Lower Third Molar Extraction Improves Treatment Outcomes.

PubMed

He, Yun; Chen, Junliang; Huang, Yue; Pan, Qin; Nie, Minhai

2017-12-01

Application of platelet-rich fibrin (PRF) during tooth extraction is able to accelerate wound healing, stimulate osseous and soft tissue regeneration, and reduce unwanted side effects. The aim of this meta-analysis was to investigate the effect of local application of PRF on controlling postoperative signs and symptoms after the extraction of an impacted lower third molar. A systematic search of PubMed, Web of Science, Embase, and the Cochrane Library was performed to identify all studies published up to October 2016 that investigated the effect of PRF on lower third molar extraction. Pain, swelling, trismus, alveolar osteitis (AO), and osteoblastic activity were extracted to evaluate the effect of PRF. After quality assessment, meta-analysis was performed with RevMan software (version 5.3; Cochrane Library Software, Oxford, UK). After the search and selection process, 10 studies were selected in this meta-analysis, including 468 cases of PRF application and 467 cases of non-PRF application. Of the studies, 9 were randomized controlled trials, including 7 split-mouth studies, and there was 1 retrospective case-control study. The results indicated that PRF significantly relieves pain (P = .01) and 3-day postoperative swelling (P = .03) and reduces the incidence of AO (P < .0001). However, there were no significant differences between the PRF and non-PRF groups with respect to 1-day postoperative swelling and osteoblastic activity. Local application of PRF after lower third molar extraction is a valid method for relieving pain and 3-day postoperative swelling and reducing the incidence of AO. For patients undergoing complicated surgical extraction, PRF might be a recommendation for local application into the sockets. Copyright © 2017 American Association of Oral and Maxillofacial Surgeons. Published by Elsevier Inc. All rights reserved.

Single-Stage Cartilage Repair Using Platelet-Rich Fibrin Scaffolds With Autologous Cartilaginous Grafts.

PubMed

Wong, Chin-Chean; Chen, Chih-Hwa; Chan, Wing P; Chiu, Li-Hsuan; Ho, Wei-Pin; Hsieh, Fon-Jou; Chen, You-Tzung; Yang, Tsung-Lin

2017-11-01

To avoid complicated procedures requiring in vitro chondrocyte expansion for cartilage repair, the development of a culture-free, 1-stage approach combining platelet-rich fibrin (PRF) and autologous cartilage grafts may be the solution. To develop a feasible 1-step procedure to combine PRF and autologous cartilage grafts for articular chondral defects. Controlled laboratory study Methods: The chemotactic effects of PRF on chondrocytes harvested from the primary culture of rabbit cartilage were evaluated in vitro and ex vivo. The rabbit chondrocytes were cultured with different concentrations of PRF media and evaluated for their cell proliferation, chondrogenic gene expression, cell viability, and extracellular matrix synthesis abilities. For the in vivo study, the chondral defects were created on established animal models of rabbits. The gross anatomy, histology, and objective scores were evaluated to validate the treatment results. PRF improved the chemotaxis, proliferation, and viability of the cultured chondrocytes. The gene expression of the chondrogenic markers, including type II collagen and aggrecan, revealed that PRF induced the chondrogenic differentiation of cultured chondrocytes. PRF increased the formation and deposition of the cartilaginous matrix produced by cultured chondrocytes. The efficacy of PRF on cell viability was comparable with that of fetal bovine serum. In animal disease models, morphologic, histological, and objectively quantitative evaluation demonstrated that PRF combined with cartilage granules was feasible in facilitating chondral repair. PRF enhances the migration, proliferation, viability, and differentiation of chondrocytes, thus showing an appealing capacity for cartilage repair. The data altogether provide evidence to confirm the feasibility of 1-stage, culture-free method of combining PRF and autologous cartilage graft for repairing articular chondral defects. The single-stage, culture-free method of combining PRF and autologous cartilage is useful for repairing articular chondral defects. These advantages benefit clinical translation by simplifying and potentiating the efficacy of autologous cartilage transplantation.

The acquisition of conditioned responding.

PubMed

Harris, Justin A

2011-04-01

This report analyzes the acquisition of conditioned responses in rats trained in a magazine approach paradigm. Following the suggestion by Gallistel, Fairhurst, and Balsam (2004), Weibull functions were fitted to the trial-by-trial response rates of individual rats. These showed that the emergence of responding was often delayed, after which the response rate would increase relatively gradually across trials. The fit of the Weibull function to the behavioral data of each rat was equaled by that of a cumulative exponential function incorporating a response threshold. Thus, the growth in conditioning strength on each trial can be modeled by the derivative of the exponential--a difference term of the form used in many models of associative learning (e.g., Rescorla & Wagner, 1972). Further analyses, comparing the acquisition of responding with a continuously reinforced stimulus (CRf) and a partially reinforced stimulus (PRf), provided further evidence in support of the difference term. In conclusion, the results are consistent with conventional models that describe learning as the growth of associative strength, incremented on each trial by an error-correction process.

Comparison of three retrievals of COSMIC GPS radio occultation results in the tropical upper troposphere and lower stratosphere

NASA Astrophysics Data System (ADS)

Noersomadi; Tsuda, Toshitaka

2017-09-01

Combining geometrical optics (GO) and wave optics (WO), the COSMIC data analysis and archive center (CDAAC) retrieved two sets of dry atmosphere temperatures ( T) from COSMIC GPS radio occultation (GPS-RO), which are called atmPrf2010 and atmPrf2013. In atmPrf2010, the sewing height between WO and GO varies between 10 and 20 km, but is fixed at 20 km for atmPrf2013. The height resolution of the atmPrf2010 depends on the sewing height, while the T profiles by atmPrf2013 are smoothed over 500 m. We also derived T by applying WO throughout the troposphere and the stratosphere up to a 30-km altitude, which is called rishfsi2013. The three retrievals have different characteristics in the height resolution around the tropopause. Therefore, we aim to examine a possible discrepancy in the statistical results of the cold-point tropopause (CPT) and the lapse rate tropopause (LRT) among the three datasets, conducting their inter-comparisons as well as the comparison between GPS-RO and the simultaneous radiosonde dataset. We investigate the T variations in the upper troposphere and lower stratosphere (UTLS) over the tropics from October 1, 2011, to March 31, 2012, when radiosonde soundings were conducted as the CINDY-DYNAMO 2011 campaign. The mean T profiles are consistent between atmPrf2010 and atmPrf2013, but rishfsi2013 results are colder (warmer) than the CDAAC retrievals below (above) the tropopause. The mean T difference between atmPrf2013 and atmPrf2010 is 0.17 K at the cold-point tropopause (CPT) and -0.38 K at the lapse rate tropopause (LRT). On the other hand, rishfsi2013 shows a colder T at CPT by -0.77 and -0.59 K relative to atmPrf2013 and atmPrf2010, respectively, and the warmer T by 0.60 and 0.20 Kd at LRT. During CINDY-DYNAMO, we found 134 radiosonde soundings that coincide with GPS-RO within ±3 h and are collocated within 200 km from GPS-RO. The mean T difference at CPT from the radiosondes is 0.32, 0.49 and -0.24 K for atmPrf2010, atmPrf2013 and rishfsi2013, respectively. Both atmPrf2013 and atmPrf2010 have a positive bias at CPT, while rishfsi2013 has a negative one. Similar comparisons at LRT are -0.45, -0.69 and -0.41 K, respectively, showing a negative bias for all GPS-RO retrievals. The results show that rishfsi2013 is consistent with the retrievals at CDAAC and the radiosondes. Due to its good height resolution, rishfsi2013 is useful for studies on mesoscale T perturbations in the UTLS.[Figure not available: see fulltext.

Leptin replacement restores supraspinal cholinergic antinociception in leptin-deficient obese mice.

PubMed

Wang, Wenfei; Baghdoyan, Helen A; Lydic, Ralph

2009-08-01

A single gene deletion causes lack of leptin and obesity in B6.V-Lep(ob) (obese; ob) mice compared with wild-type C57BL/6J (B6) mice. This study compared the phenotype of nociception and supraspinal antinociception in obese and B6 mice by testing 2 hypotheses: (1) microinjection of cholinomimetics or an adenosine receptor agonist, but not morphine, into the pontine reticular formation (PRF) is antinociceptive in B6 but not obese mice, and (2) leptin replacement in obese mice attenuates differences in nociceptive responses between obese and B6 mice. Adult male mice (n = 22) were implanted with microinjection guide tubes aimed for the PRF. The PRF was injected with neostigmine, carbachol, nicotine, N(6)-p-sulfophenyladenosine (SPA), morphine, or saline (control), and latency to paw withdrawal (PWL) from a thermal stimulus was recorded. B6 and ob mice did not differ in PWL after saline microinjection into the PRF. Neostigmine, carbachol, and SPA caused PWL to increase significantly in B6 but not obese mice. An additional 15 obese mice were implanted with osmotic pumps that delivered leptin for 7 days. Leptin replacement in obese mice restored the analgesic effect of PRF neostigmine to the level displayed by B6 mice. The results show for the first time that leptin significantly alters supraspinal cholinergic antinociception. This study specifies a brain region (the pontine reticular formation), cholinergic neurotransmission, and a protein (leptin) modulating thermal nociception. The results are relevant for efforts to understand the association between obesity, disordered sleep, and hyperalgesia.

Evaluation of osteoblastic activity in extraction sockets treated with platelet-rich fibrin

PubMed Central

Tumer, Celal; Ugur, Omer; Vatankulu, Betul

2015-01-01

Objective: The aim of this study was to determine whether the use of platelet rich fibrin (PRF) improved the healing of extraction sockets. Study Design: A total of 20 patients with bilateral soft tissue impacted mandibular third molars were included in this study. The left and right third molars were extracted during the same session. Subsequently, the PRF membrane was randomly administered to one of the extraction sockets, whereas the contra lateral sockets were left without treatment. On postoperative 30. and 90. days, panoramic images and bone scintigrams were taken to evaluate the bone healing between PRF-treated and non-PRF-treated sockets. Also, periodontal evaluation was performed in the same control sessions. Dependent group t test for paired samples was used for statistical analysis. Results: The average increase in technetium-99m methylene diphosphonate uptake as an indication of enhanced bone healing did not differ significantly between PRF-treated and non-PRF-treated sockets 30 and 90 days post operatively. Radio opacity that can show the bone healing on panoramic images were measured by Image J programmer and they did not differ significantly. Also periodontal values did not differ significantly. Conclusions: PRF might not lead to enhanced bone healing in impacted mandibular third molar extraction sockets 30 and 90 days after surgery. It is thought that PRF has the potential characteristics of an autologous fibrin matrix and can accelerate the healing. To better understand the effects of PRF on healing, further research is warranted with larger sample sizes. Key words:PRF, scintigraphy, healing, extraction sockets. PMID:25475771

Effect of Pulsed Radiofrequency on Rat Sciatic Nerve Chronic Constriction Injury: A Preliminary Study

PubMed Central

Li, Duo-Yi; Meng, Lan; Ji, Nan; Luo, Fang

2015-01-01

Background: Pulsed radiofrequency (PRF) application to the dorsal root ganglia can reduce neuropathic pain (NP) in animal models, but the effect of PRF on damaged peripheral nerves has not been examined. We investigated the effect of PRF to the rat sciatic nerve (SN) on pain-related behavior and SN ultrastructure following chronic constriction injury (CCI). Methods: The analgesic effect was measured by hindpaw mechanical withdrawal threshold (MWT) and thermal withdrawal latency (TWL). Twenty rats with NP induced by ligating the common SN were then randomly divided into a PRF treatment group and a sham group. The contralateral SN served as a control. The MWT and TWL were determined again 2, 4, 6, 8, 10, 12, and 14 days after the PRF or sham treatment. On day 14, ipsilateral and contralateral common SNs were excised and examined by electron microscopy. Results: Ipsilateral MWT was significantly reduced and TWL significantly shorter compared to the contralateral side 14 days after CCI (both P = 0.000). In the PRF group, MWT was significantly higher and TWL significantly longer 14 days after the PRF treatment compared to before PRF treatment (both P = 0.000), while no such difference was observed in the sham group (P > 0.05). Electron microscopy revealed extensive demyelination and collagen fiber formation in the ipsilateral SN of sham-treated rats but sparse demyelination and some nerve fiber regrowth in the PRF treatment group. Conclusions: Hyperalgesia is relieved, and ultrastructural damage ameliorated after direct PRF treatment to the SN in the CCI rat model of NP. PMID:25673460

Clinical Application of Platelet-Rich Fibrin in Plastic and Reconstructive Surgery: A Systematic Review.

PubMed

Yu, Panxi; Zhai, Zhen; Jin, Xiaolei; Yang, Xiaonan; Qi, Zuoliang

2018-04-01

Platelet-rich fibrin (PRF) has been applied in the clinical field for more than a decade, but largely in oral surgery and implant dentistry. Its utilization in plastic and reconstructive surgery is limited and lacking a comprehensive review. Hence, this article focuses on the various clinical applications of PRF pertaining to the plastic and reconstructive field through a systematic review. In this review, articles describing the clinical application of PRF in plastic and reconstructive surgery were screened using predetermined inclusion and exclusion criteria. The articles were summarized and divided into groups based on the utilization of PRF. The effects and complications of PRF were analyzed and concluded. Among the 634 articles searched, 7 articles describing 151 cases are eligible. PRF was applied on 116 (76.8%) wounds to facilitate tissue healing, and the complete wound closure rate was 91.4% (106/116). Otherwise, PRF was applied in 10 (6.6%) cases of zygomaticomaxillary fracture to reconstruct orbital floor defects and in 25 (16.6%) cases of facial autologous fat grafts to increase the fat retention rate successfully. There is no report of PRF-related complications. PRF could facilitate wound healing, including the healing of soft tissues and bony tissues, and facilitate fat survival rate. Further studies are needed to test the mechanism of PRF and expand its scope of application in plastic and reconstructive surgery. This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Effects of RO 15-1788 on a running response rewarded on continuous or partial reinforcement schedules.

PubMed

Hawkins, M; Sinden, J; Martin, I; Gray, J A

1988-01-01

Two experiments were run in which rats were rewarded with food for running in a straight alley at one trial a day, followed by extinction of the running response. During acquisition of the response, reward was delivered either on a continuous reinforcement (CRF) or on a quasirandom 50% partial reinforcement (PRF) schedule. The groups given PRF were more resistant to extinction than those given CRF, the well-known partial reinforcement extinction effect. In Experiment 1 different groups of rats were injected during acquisition only with 1, 5 or 10 mg/kg of the benzodiazepine antagonist, RO 15-1788, or with placebo. In Experiment 2, 5 mg/kg RO 15-1788 or placebo were administered in a full cross-over design during acquisition, extinction or both. At the end of Experiment 2 only [3H]-flunitrazepam binding was measured in either the presence or absence of added gamma-aminobutyrate (GABA) in homogenates of hippocampi dissected from the animals that had received behavioural training. The drug affected running speeds during both acquisition and extinction in different ways depending upon the schedule of reinforcement (CRF or PRF) and also gave rise to enhanced GABA stimulation of [3H]-flunitrazepam binding. The results are discussed in relation to the hypothesis that the neurochemical pathways by which reinforcement schedules modify behaviour include a step influenced by benzodiazepine receptors.

Novel Escherichia coli RF1 mutants with decreased translation termination activity and increased sensitivity to the cytotoxic effect of the bacterial toxins Kid and RelE

PubMed Central

Diago-Navarro, Elizabeth; Mora, Liliana; Buckingham, Richard H; Díaz-Orejas, Ramón; Lemonnier, Marc

2008-01-01

Novel mutations in prfA, the gene for the polypeptide release factor RF1 of Escherichia coli, were isolated using a positive genetic screen based on the parD (kis, kid) toxin–antitoxin system. This original approach allowed the direct selection of mutants with altered translational termination efficiency at UAG codons. The isolated prfA mutants displayed a ∼10-fold decrease in UAG termination efficiency with no significant changes in RF1 stability in vivo. All three mutations, G121S, G301S and R303H, were situated close to the nonsense codon recognition site in RF1:ribosome complexes. The prfA mutants displayed increased sensitivity to the RelE toxin encoded by the relBE system of E. coli, thus providing in vivo support for the functional interaction between RF1 and RelE. The prfA mutants also showed increased sensitivity to the Kid toxin. Since this toxin can cleave RNA in a ribosome-independent manner, this result was not anticipated and provided first evidence for the involvement of RF1 in the pathway of Kid toxicity. The sensitivity of the prfA mutants to RelE and Kid was restored to normal levels upon overproduction of the wild-type RF1 protein. We discuss these results and their utility for the design of novel antibacterial strategies in the light of the recently reported structure of ribosome-bound RF1. PMID:19019162

Comparative Effectivenesses of Pulsed Radiofrequency and Transforaminal Steroid Injection for Radicular Pain due to Disc Herniation: a Prospective Randomized Trial.

PubMed

Lee, Dong Gyu; Ahn, Sang-Ho; Lee, Jungwon

2016-08-01

Transforaminal Epidural steroid injections (TFESI) have been widely adopted to alleviate and control radicular pain in accord with current guidelines. However, sometimes repeated steroid injections have adverse effects, and thus, this prospective randomized trial was undertaken to compare the effectivenesses of pulsed radiofrequency (PRF) administered to a targeted dorsal root ganglion (DRG) and TFESI for the treatment of radicular pain due to disc herniation. Subjects were recruited when first proved unsuccessful (defined as a score of > 4 on a visual analogue scale (VAS; 0-10 mm) and of > 30% according to the Oswestry Disability Index (ODI) or the Neck Disability Index (NDI)). Forty-four patients that met the inclusion criteria were enrolled. The 38 subjects were randomly assigned to receive either PRF (PRF group; n = 19) or additional TFESI (TFESI group; n = 19) and were then followed for 2, 4, 8, and 12 weeks. To evaluate pain intensity were assessed by VAS. ODI and NDI were applied to evaluate functional disability. Mean VAS scores for cervical and lumbar radicular pain were significantly lower 12 weeks after treatment in both study groups. NDI and ODI scores also declined after treatment. However, no statistically significant difference was observed between the PRF and TFESI groups in terms of VAS, ODI, or NDI scores at any time during follow-up. PRF administered to a DRG might be as effective as TFESI in terms of attenuating radicular pain caused by disc herniation, and its use would avoid the adverse effects of steroid.

PRF Ambiguity Detrmination for Radarsat ScanSAR System

NASA Technical Reports Server (NTRS)

Jin, Michael Y.

1998-01-01

PRF ambiguity is a potential problem for a spaceborne SAR operated at high frequencies. For a strip mode SAR, there were several approaches to solve this problem. This paper, however, addresses PRF ambiguity determination algorithms suitable for a burst mode SAR system such as the Radarsat ScanSAR. The candidate algorithms include the wavelength diversity algorithm, range look cross correlation algorithm, and multi-PRF algorithm.

Evaluation of osteoblastic activity in extraction sockets treated with platelet-rich fibrin.

PubMed

Baslarli, Ozgur; Tumer, Celal; Ugur, Omer; Vatankulu, Betul

2015-01-01

The aim of this study was to determine whether the use of platelet rich fibrin (PRF) improved the healing of extraction sockets. A total of 20 patients with bilateral soft tissue impacted mandibular third molars were included in this study. The left and right third molars were extracted during the same session. Subsequently, the PRF membrane was randomly administered to one of the extraction sockets, whereas the contralateral sockets were left without treatment. On postoperative 30. and 90. days, panoramic images and bone scintigrams were taken to evaluate the bone healing between PRF-treated and non-PRF-treated sockets. Also, periodontal evaluation was performed in the same control sessions. Dependent group t test for paired samples was used for statistical analysis. The average increase in technetium-99m methylene diphosphonate uptake as an indication of enhanced bone healing did not differ significantly between PRF-treated and non-PRF-treated sockets 30 and 90 days postoperatively. Radio-opacity that can show the bone healing on panoramic images were measured by Image J programme and they did not differ significantly. Also periodontal values did not differ significantly. PRF might not lead to enhanced bone healing in impacted mandibular third molar extraction sockets 30 and 90 days after surgery. It is thought that PRF has the potential characteristics of an autologous fibrin matrix and can accelerate the healing. To better understand the effects of PRF on healing, further research is warranted with larger sample sizes.

Pulsed radiofrequency reduced complete Freund's adjuvant-induced mechanical hyperalgesia via the spinal c-Jun N-terminal kinase pathway.

PubMed

Chen, Kuan-Hung; Yang, Chien-Hui; Juang, Sin-Ei; Huang, Hui-Wen; Cheng, Jen-Kun; Sheen-Chen, Shyr-Ming; Cheng, Jiin-Tsuey; Lin, Chung-Ren

2014-03-01

Pulsed radiofrequency (PRF) treatment involves the pulsed application of a radiofrequency electric field to a nerve. The technology offers pain relief for patients suffering from chronic pain who do not respond well to conventional treatments. We tested whether PRF treatment attenuated complete Freund's adjuvant (CFA) induced inflammatory pain. The profile of spinal c-Jun N-terminal kinases (JNKs) phosphorylation was evaluated to elucidate the potential mechanism. Injection of CFA into the unilateral hind paw of rats induced mechanical hyperalgesia in both the ipsilateral and contralateral hind paws. We administered 500-kHz PRF treatment in 20-ms pulses, at a rate of 2 Hz (2 pulses per second) either to the sciatic nerve in the mid-thigh, or to the L4 anterior primary ramus just distal to the intervertebral foramen in both the CFA group and no-PRF group rats. Tissue samples were examined at 1, 3, 7, and 14 days following PRF treatments. Behavioral studies showed that PRF applied close to the dorsal root ganglion (DRG) significantly attenuated CFA-induced mechanical hyperalgesia compared to no-PRF group (P < .05). And western blotting revealed significant attenuation of the activation of JNK in the spinal dorsal horn compared to no-PRF group animals (P < .05). Application of PRF close to DRG provides an effective treatment for CFA-induced persistent mechanical hyperalgesia by attenuating JNK activation in the spinal dorsal horn.

Long-Term Anti-Allodynic Effect of Immediate Pulsed Radiofrequency Modulation through Down-Regulation of Insulin-Like Growth Factor 2 in a Neuropathic Pain Model.

PubMed

Yeh, Chun-Chang; Sun, Hsiao-Lun; Huang, Chi-Jung; Wong, Chih-Shung; Cherng, Chen-Hwan; Huh, Billy Keon; Wang, Jinn-Shyan; Chien, Chih-Cheng

2015-11-13

Pulsed radiofrequency (PRF) is effective in the treatment of neuropathic pain in clinical practice. Its application to sites proximal to nerve injury can inhibit the activity of extra-cellular signal-regulated kinase (ERK) for up to 28 days. The spared nerve injury (SNI)+ immPRF group (immediate exposure to PRF for 6 min after SNI) exhibited a greater anti-allodynic effect compared with the control group (SNI alone) or the SNI + postPRF group (application of PRF for 6 min on the 14th day after SNI). Insulin-like growth factor 2 (IGF2) was selected using microarray assays and according to web-based gene ontology annotations in the SNI + immPRF group. An increase in IGF2 and activation of ERK1/2 were attenuated by the immPRF treatment compared with an SNI control group. Using immunofluorescent staining, we detected co-localized phosphorylated ERK1/2 and IGF2 in the dorsal horn regions of rats from the SNI group, where the IGF2 protein predominantly arose in CD11b- or NeuN-positive cells, whereas IGF2 immunoreactivity was not detected in the SNI + immPRF group. Taken together, these results suggest that PRF treatment immediately after nerve injury significantly inhibited the development of neuropathic pain with a lasting effect, most likely through IGF2 down-regulation and the inhibition of ERK1/2 activity primarily in microglial cells.

The development and validation of a LIPUS system with preliminary observations of ultrasonic effects on human adult stem cells.

PubMed

Marvel, Skylar; Okrasinski, Stan; Bernacki, Susan H; Loboa, Elizabeth; Dayton, Paul A

2010-09-01

To study the potential effects of low-intensity pulsed ultrasound (LIPUS) on cell response in vitro, the ability to alter LIPUS parameters is required. However, commercial LIPUS systems have very little control over parameter selection. In this study, a custom LIPUS system was designed and validated by exploring the effects of using different pulse repetition frequency (PRF) parameters on human adipose derived adult stem cells (hASCs) and bone marrow derived mesenchymal stem cells (hMSCs), two common stem cell sources for creating bone constructs in vitro. Changing the PRF was found to affect cellular response to LIPUS stimulation for both cell types. Proliferation of LIPUS-stimulated cells was found to decrease for hASCs by d 7 for all three groups compared with unstimulated control cells (P = 0.008, 0.011, 0.014 for 1 Hz, 100 Hz and 1 kHz PRF, respectively) and for hMSCs by d 14 (donor 1: P = 0.0005, 0.0002, 0.0003; donor 2: P = 0.0003, 0.0002, 0.0001; for PRFs of 1 Hz, 100 Hz, and 1 kHz, respectively). Additionally, LIPUS was shown to strongly accelerate osteogenic differentiation of hASCs based on amount of calcium accretion normalized by total DNA (P = 0.003, 0.001, 0.003, and 0.032 between control/100 Hz, control/1 kHz, 1 Hz/1 kHz, and 100 Hz/1 kHz pulse repetition frequencies, respectively). These findings promote the study of using LIPUS to induce osteogenic differentiation and further encourage the exploration of LIPUS parameter optimization. The custom LIPUS system was successfully designed to allow extreme parameter variation, specifically PRF, and encourages further studies.

Performance analysis of multiple PRF technique for ambiguity resolution

NASA Technical Reports Server (NTRS)

Chang, C. Y.; Curlander, J. C.

1992-01-01

For short wavelength spaceborne synthetic aperture radar (SAR), ambiguity in Doppler centroid estimation occurs when the azimuth squint angle uncertainty is larger than the azimuth antenna beamwidth. Multiple pulse recurrence frequency (PRF) hopping is a technique developed to resolve the ambiguity by operating the radar in different PRF's in the pre-imaging sequence. Performance analysis results of the multiple PRF technique are presented, given the constraints of the attitude bound, the drift rate uncertainty, and the arbitrary numerical values of PRF's. The algorithm performance is derived in terms of the probability of correct ambiguity resolution. Examples, using the Shuttle Imaging Radar-C (SIR-C) and X-SAR parameters, demonstrate that the probability of correct ambiguity resolution obtained by the multiple PRF technique is greater than 95 percent and 80 percent for the SIR-C and X-SAR applications, respectively. The success rate is significantly higher than that achieved by the range cross correlation technique.

Cancer resistance of SR/CR mice in the genetic knockout backgrounds of leukocyte effector mechanisms: determinations for functional requirements.

PubMed

Sanders, Anne M; Stehle, John R; Blanks, Michael J; Riedlinger, Gregory; Kim-Shapiro, Jung W; Monjazeb, Arta M; Adams, Jonathan M; Willingham, Mark C; Cui, Zheng

2010-03-31

Spontaneous Regression/Complete Resistant (SR/CR) mice are a colony of cancer-resistant mice that can detect and rapidly destroy malignant cells with innate cellular immunity, predominately mediated by granulocytes. Our previous studies suggest that several effector mechanisms, such as perforin, granzymes, or complements, may be involved in the killing of cancer cells. However, none of these effector mechanisms is known as critical for granulocytes. Additionally, it is unclear which effector mechanisms are required for the cancer killing activity of specific leukocyte populations and the survival of SR/CR mice against the challenges of lethal cancer cells. We hypothesized that if any of these effector mechanisms was required for the resistance to cancer cells, its functional knockout in SR/CR mice should render them sensitive to cancer challenges. This was tested by cross breeding SR/CR mice into the individual genetic knockout backgrounds of perforin (Prf-/-), superoxide (Cybb-/), or inducible nitric oxide (Nos2-/). SR/CR mice were bred into individual Prf-/-, Cybb-/-, or Nos2-/- genetic backgrounds and then challenged with sarcoma 180 (S180). Their overall survival was compared to controls. The cancer killing efficiency of purified populations of macrophages and neutrophils from these immunodeficient mice was also examined. When these genetically engineered mice were challenged with cancer cells, the knockout backgrounds of Prf-/-, Cybb-/-, or Nos2-/- did not completely abolish the SR/CR cancer resistant phenotype. However, the Nos2-/- background did appear to weaken the resistance. Incidentally, it was also observed that the male mice in these immunocompromised backgrounds tended to be less cancer-resistant than SR/CR controls. Despite the previously known roles of perforin, superoxide or nitric oxide in the effector mechanisms of innate immune responses, these effector mechanisms were not required for cancer-resistance in SR/CR mice. The resistance was functional when any one of these effector mechanisms was completely absent, except some noticeably reduced penetrance, but not abolishment, of the phenotype in the male background in comparison to female background. These results also indicate that some other effector mechanism(s) of granulocytes may be involved in the killing of cancer cells in SR/CR mice.

Lyophilized platelet-rich fibrin (PRF) promotes craniofacial bone regeneration through Runx2.

PubMed

Li, Qi; Reed, David A; Min, Liu; Gopinathan, Gokul; Li, Steve; Dangaria, Smit J; Li, Leo; Geng, Yajun; Galang, Maria-Therese; Gajendrareddy, Praveen; Zhou, Yanmin; Luan, Xianghong; Diekwisch, Thomas G H

2014-05-14

Freeze-drying is an effective means to control scaffold pore size and preserve its composition. The purpose of the present study was to determine the applicability of lyophilized Platelet-rich fibrin (LPRF) as a scaffold for craniofacial tissue regeneration and to compare its biological effects with commonly used fresh Platelet-rich fibrin (PRF). LPRF caused a 4.8-fold±0.4-fold elevation in Runt-related transcription factor 2 (Runx2) expression in alveolar bone cells, compared to a 3.6-fold±0.2-fold increase when using fresh PRF, and a more than 10-fold rise of alkaline phosphatase levels and mineralization markers. LPRF-induced Runx2 expression only occurred in alveolar bone and not in periodontal or dental follicle cells. LPRF also caused a 1.6-fold increase in osteoblast proliferation (p<0.001) when compared to fresh PRF. When applied in a rat craniofacial defect model for six weeks, LPRF resulted in 97% bony coverage of the defect, compared to 84% for fresh PRF, 64% for fibrin, and 16% without scaffold. Moreover, LPRF thickened the trabecular diameter by 25% when compared to fresh PRF and fibrin, and only LPRF and fresh PRF resulted in the formation of interconnected trabeculae across the defect. Together, these studies support the application of lyophilized PRF as a biomimetic scaffold for craniofacial bone regeneration and mineralized tissue engineering.

Beef Fat Enriched with Polyunsaturated Fatty Acid Biohydrogenation Products Improves Insulin Sensitivity Without Altering Dyslipidemia in Insulin Resistant JCR:LA-cp Rats.

PubMed

Diane, Abdoulaye; Borthwick, Faye; Mapiye, Cletos; Vahmani, Payam; David, Rolland C; Vine, Donna F; Dugan, Michael E R; Proctor, Spencer D

2016-07-01

The main dietary sources of trans fatty acids are partially hydrogenated vegetable oils (PHVO), and products derived from polyunsaturated fatty acid biohydrogenation (PUFA-BHP) in ruminants. Trans fatty acid intake has historically been associated with negative effects on health, generating an anti-trans fat campaign to reduce their consumption. The profiles and effects on health of PHVO and PUFA-BHP can, however, be quite different. Dairy products naturally enriched with vaccenic and rumenic acids have many purported health benefits, but the putative benefits of beef fat naturally enriched with PUFA-BHP have not been investigated. The objective of the present experiment was to determine the effects of beef peri-renal fat (PRF) with differing enrichments of PUFA-BHP on lipid and insulin metabolism in a rodent model of dyslipidemia and insulin resistance (JCR:LA-cp rat). The results showed that 6 weeks of diet supplementation with beef PRF naturally enriched due to flaxseed (FS-PRF) or sunflower-seed (SS-PRF) feeding to cattle significantly improved plasma fasting insulin levels and insulin sensitivity, postprandial insulin levels (only in the FS-PRF) without altering dyslipidemia. Moreover, FS-PRF but not SS-PRF attenuated adipose tissue accumulation. Therefore, enhancing levels of PUFA-BHP in beef PRF with FS feeding may be a useful approach to maximize the health-conferring value of beef-derived fats.

Effect of platelet-rich fibrin on frequency of alveolar osteitis following mandibular third molar surgery: a double-blinded randomized clinical trial.

PubMed

Eshghpour, Majid; Dastmalchi, Parisa; Nekooei, Amir Hossein; Nejat, AmirHossein

2014-08-01

To evaluate the effectiveness of platelet-rich fibrin (PRF) in preventing the development of alveolar osteitis (AO). In a double-blinded study, patients with bilateral impacted mandibular third molars underwent surgical extractions, with one socket receiving PRF and the other one serving as a control. The surgeon and patient were unaware of the study or control side. The predictor variable was the PRF application and was categorized as PRF and non-PRF. The outcome variable was the development of AO during the first postoperative week. Other study variables included age, gender, smoking status, irrigation volume, extraction difficulty, surgeon experience, and number of anesthetic cartridges. Data were analyzed using χ(2) and t tests, with the significance level set at a P value less than .05. Seventy-eight patients (mean age, 25 yr) underwent 156 impacted third molar surgeries. The overall frequency of AO was 14.74% for all surgeries. The frequency of AO in the PRF group was significantly lower than in the non-PRF group (odds ratio = 0.44; P < .05). Based on the results of the present study, PRF application may decrease the risk of AO development after mandibular third molar surgery. Copyright © 2014 American Association of Oral and Maxillofacial Surgeons. Published by Elsevier Inc. All rights reserved.

Antimicrobial medium- and long-chain free fatty acids prevent PrfA-dependent activation of virulence genes in Listeria monocytogenes.

PubMed

Sternkopf Lillebæk, Eva Maria; Lambert Nielsen, Stine; Scheel Thomasen, Rikke; Færgeman, Nils J; Kallipolitis, Birgitte H

The foodborne pathogen Listeria monocytogenes is the causative agent of the invasive disease listeriosis. Infection by L. monocytogenes involves bacterial crossing of the intestinal barrier and intracellular replication in a variety of host cells. The PrfA protein is the master regulator of virulence factors required for bacterial entry, intracellular replication and cell-to-cell spread. PrfA-dependent activation of virulence genes occurs primarily in the blood and during intracellular infection. In contrast, PrfA does not play a significant role in regulation of virulence gene expression in the intestinal environment. In the gastrointestinal phase of infection, the bacterium encounters a variety of antimicrobial agents, including medium- and long-chain free fatty acids that are commonly found in our diet and as active components of bile. Here we show that subinhibitory concentrations of specific antimicrobial free fatty acids act to downregulate transcription of PrfA-activated virulence genes. Interestingly, the inhibitory effect is also evident in cells encoding a constitutively active variant of PrfA. Collectively, our data suggest that antimicrobial medium- and long-chain free fatty acids may act as signals to prevent PrfA-mediated activation of virulence genes in environments where PrfA activation is not required, such as in food and the gastrointestinal tract. Copyright © 2017 Institut Pasteur. Published by Elsevier Masson SAS. All rights reserved.

Estimating minimal important differences for several scales assessing function and quality of life in patients with attention-deficit/hyperactivity disorder.

PubMed

Hodgkins, Paul; Lloyd, Andrew; Erder, M Haim; Setyawan, Juliana; Weiss, Margaret D; Sasané, Rahul; Nafees, Beenish

2017-02-01

Defining minimal important difference (MID) is critical to interpreting patient-reported outcomes data and treatment efficacy in clinical trials. This study estimates the MID for the Weiss Functional Impairment Rating Scale-Parent Report (WFIRS-P) and the Child Health and Illness Profile-Parent Report (CHIP-CE-PRF76) among parents of young people with attention-deficit/hyperactivity disorder (ADHD) in the UK. Parents of children (6-12 years; n=100) and adolescents (13-17 years; n=117) with ADHD completed a socio-demographic form, the CHIP-CE-PRF76, the WFIRS-P, and the Pediatric Quality of Life scale at baseline and 4 weeks later. At follow-up, a subset of parents completed anchor questions measuring change in the child/adolescent from baseline. MIDs were estimated using anchor-based and distribution-based methods, and separately for children and adolescents. The MID estimates for overall change in the WFIRS-P total score ranged from 11.31 (standard error of measurement) to 13.47 (anchor) for the total sample. The range of MID estimates for the CHIP-CE-PRF76 varied by domain: 6.80-7.41 (satisfaction), 6.18-7.34 (comfort), 5.60-6.72 (resilience), 6.06-7.57 (risk avoidance), and 4.00-5.63 (achievement) for the total sample. Overall, MID estimates for WFIRS-P MID and CHIP-CE-PRF76 were slightly higher for adolescents than for children. This study estimated MIDs for these instruments using several methods. The observed convergence of the MID estimates increases confidence in their reliability and could assist clinicians and decision makers in deriving meaningful interpretations of observed changes in the WFIRS-P and CHIP-CE in clinical trials and practice.

Is the Cortical Deficit in Amblyopia Due to Reduced Cortical Magnification, Loss of Neural Resolution, or Neural Disorganization?

PubMed

Clavagnier, Simon; Dumoulin, Serge O; Hess, Robert F

2015-11-04

The neural basis of amblyopia is a matter of debate. The following possibilities have been suggested: loss of foveal cells, reduced cortical magnification, loss of spatial resolution of foveal cells, and topographical disarray in the cellular map. To resolve this we undertook a population receptive field (pRF) functional magnetic resonance imaging analysis in the central field in humans with moderate-to-severe amblyopia. We measured the relationship between averaged pRF size and retinal eccentricity in retinotopic visual areas. Results showed that cortical magnification is normal in the foveal field of strabismic amblyopes. However, the pRF sizes are enlarged for the amblyopic eye. We speculate that the pRF enlargement reflects loss of cellular resolution or an increased cellular positional disarray within the representation of the amblyopic eye. The neural basis of amblyopia, a visual deficit affecting 3% of the human population, remains a matter of debate. We undertook the first population receptive field functional magnetic resonance imaging analysis in participants with amblyopia and compared the projections from the amblyopic and fellow normal eye in the visual cortex. The projection from the amblyopic eye was found to have a normal cortical magnification factor, enlarged population receptive field sizes, and topographic disorganization in all early visual areas. This is consistent with an explanation of amblyopia as an immature system with a normal complement of cells whose spatial resolution is reduced and whose topographical map is disordered. This bears upon a number of competing theories for the psychophysical defect and affects future treatment therapies. Copyright © 2015 the authors 0270-6474/15/3514740-16$15.00/0.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pérez, Juan J.; Pérez-Cajaraville, Juan J.; Muñoz, Víctor

Purpose: Pulsed RF (PRF) is a nonablative technique for treating neuropathic pain. Bipolar PRF application is currently aimed at creating a “strip lesion” to connect the electrode tips; however, the electrical and thermal performance during bipolar PRF is currently unknown. The objective of this paper was to study the temperature and electric field distributions during bipolar PRF. Methods: The authors developed computer models to study temperature and electric field distributions during bipolar PRF and to assess the possible ablative thermal effect caused by the accumulated temperature spikes, along with any possible electroporation effects caused by the electrical field. The authorsmore » also modeled the bipolar ablative mode, known as bipolar Continuous Radiofrequency (CRF), in order to compare both techniques. Results: There were important differences between CRF and PRF in terms of electrical and thermal performance. In bipolar CRF: (1) the initial temperature of the tissue impacts on temperature progress and hence on the thermal lesion dimension; and (2) at 37 °C, 6-min of bipolar CRF creates a strip thermal lesion between the electrodes when these are separated by a distance of up to 20 mm. In bipolar PRF: (1) an interelectrode distance shorter than 5 mm produces thermal damage (i.e., ablative effect) in the intervening tissue after 6 min of bipolar RF; and (2) the possible electroporation effect (electric fields higher than 150 kV m{sup −1}) would be exclusively circumscribed to a very small zone of tissue around the electrode tip. Conclusions: The results suggest that (1) the clinical parameters considered to be suitable for bipolar CRF should not necessarily be considered valid for bipolar PRF, and vice versa; and (2) the ablative effect of the CRF mode is mainly due to its much greater level of delivered energy than is the case in PRF, and therefore at same applied energy levels, CRF, and PRF are expected to result in same outcomes in terms of thermal damage zone dimension.« less

Computer modeling of electrical and thermal performance during bipolar pulsed radiofrequency for pain relief.

PubMed

Pérez, Juan J; Pérez-Cajaraville, Juan J; Muñoz, Víctor; Berjano, Enrique

2014-07-01

Pulsed RF (PRF) is a nonablative technique for treating neuropathic pain. Bipolar PRF application is currently aimed at creating a "strip lesion" to connect the electrode tips; however, the electrical and thermal performance during bipolar PRF is currently unknown. The objective of this paper was to study the temperature and electric field distributions during bipolar PRF. The authors developed computer models to study temperature and electric field distributions during bipolar PRF and to assess the possible ablative thermal effect caused by the accumulated temperature spikes, along with any possible electroporation effects caused by the electrical field. The authors also modeled the bipolar ablative mode, known as bipolar Continuous Radiofrequency (CRF), in order to compare both techniques. There were important differences between CRF and PRF in terms of electrical and thermal performance. In bipolar CRF: (1) the initial temperature of the tissue impacts on temperature progress and hence on the thermal lesion dimension; and (2) at 37 °C, 6-min of bipolar CRF creates a strip thermal lesion between the electrodes when these are separated by a distance of up to 20 mm. In bipolar PRF: (1) an interelectrode distance shorter than 5 mm produces thermal damage (i.e., ablative effect) in the intervening tissue after 6 min of bipolar RF; and (2) the possible electroporation effect (electric fields higher than 150 kV m(-1)) would be exclusively circumscribed to a very small zone of tissue around the electrode tip. The results suggest that (1) the clinical parameters considered to be suitable for bipolar CRF should not necessarily be considered valid for bipolar PRF, and vice versa; and (2) the ablative effect of the CRF mode is mainly due to its much greater level of delivered energy than is the case in PRF, and therefore at same applied energy levels, CRF, and PRF are expected to result in same outcomes in terms of thermal damage zone dimension.

Sheet of osteoblastic cells combined with platelet-rich fibrin improves the formation of bone in critical-size calvarial defects in rabbits.

PubMed

Wang, Zhifa; Hu, Hanqing; Li, Zhijin; Weng, Yanming; Dai, Taiqiang; Zong, Chunlin; Liu, Yanpu; Liu, Bin

2016-04-01

Techniques that use sheets of cells have been successfully used in various types of tissue regeneration, and platelet-rich fibrin (PRF) can be used as a source of growth factors to promote angiogenesis. We have investigated the effects of the combination of PRF and sheets of mesenchymal stem cells (MSC) from bone marrow on the restoration of bone in critical-size calvarial defects in rabbits to find out whether the combination promotes bony healing. Sheets of MSC and PRF were prepared from the same donor. We then implanted the combined MSC and PRF in critical-size calvarial defects in rabbits and assessed bony restoration by microcomputed tomography (microCT) and histological analysis. The results showed that PRF significantly increased bony regeneration at 8 weeks after implantation of sheets of MSC and PRF compared with sheets of MSC alone (p=0.0048). Our results indicate that the combination of sheets of MSC and PRF increases bone regeneration in critical-size calvarial defects in rabbits, and provides a new way to improve skeletal healing. Copyright © 2015 The British Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.

Genomic basis of broad host range and environmental adaptability of Rhizobium tropici CIAT 899 and Rhizobium sp. PRF 81 which are used in inoculants for common bean (Phaseolus vulgaris L.)

PubMed Central

2012-01-01

Background Rhizobium tropici CIAT 899 and Rhizobium sp. PRF 81 are α-Proteobacteria that establish nitrogen-fixing symbioses with a range of legume hosts. These strains are broadly used in commercial inoculants for application to common bean (Phaseolus vulgaris) in South America and Africa. Both strains display intrinsic resistance to several abiotic stressful conditions such as low soil pH and high temperatures, which are common in tropical environments, and to several antimicrobials, including pesticides. The genetic determinants of these interesting characteristics remain largely unknown. Results Genome sequencing revealed that CIAT 899 and PRF 81 share a highly-conserved symbiotic plasmid (pSym) that is present also in Rhizobium leucaenae CFN 299, a rhizobium displaying a similar host range. This pSym seems to have arisen by a co-integration event between two replicons. Remarkably, three distinct nodA genes were found in the pSym, a characteristic that may contribute to the broad host range of these rhizobia. Genes for biosynthesis and modulation of plant-hormone levels were also identified in the pSym. Analysis of genes involved in stress response showed that CIAT 899 and PRF 81 are well equipped to cope with low pH, high temperatures and also with oxidative and osmotic stresses. Interestingly, the genomes of CIAT 899 and PRF 81 had large numbers of genes encoding drug-efflux systems, which may explain their high resistance to antimicrobials. Genome analysis also revealed a wide array of traits that may allow these strains to be successful rhizosphere colonizers, including surface polysaccharides, uptake transporters and catabolic enzymes for nutrients, diverse iron-acquisition systems, cell wall-degrading enzymes, type I and IV pili, and novel T1SS and T5SS secreted adhesins. Conclusions Availability of the complete genome sequences of CIAT 899 and PRF 81 may be exploited in further efforts to understand the interaction of tropical rhizobia with common bean and other legume hosts. PMID:23270491

Growth factor and proteinase profile of Vivostat® platelet-rich fibrin linked to tissue repair.

PubMed

Agren, M S; Rasmussen, K; Pakkenberg, B; Jørgensen, B

2014-07-01

Autologous platelet-rich fibrin (PRF(®)) is prepared by the automatic Vivostat(®) system. Conflicting results with Vivostat PRF in acute wound healing prompted us to examine its cellular and biomolecular composition. Specifically, platelets, selected growth factors and matrix metalloproteinase (MMP)-9 were quantified using novel analytical methods. Ten healthy non-thrombocytopenic volunteers donated blood for generation of intermediate fibrin-I and final PRF. Anticoagulated whole blood and serum procured in parallel served as baseline controls. Leucocyte, erythrocyte and platelet counts in whole blood and fibrin-I were determined by automated haematology analyser. Platelet concentration in PRF was quantified manually by stereologic analysis of Giemsa-stained tissue sections, and the total content of five growth factors and MMP-9 by enzyme-linked immunosorbent assays. The number of leucocytes and erythrocytes was reduced (P < 0·001), whereas platelets increased (P < 0·001) in fibrin-I versus whole blood. PRF contained 982 ± 206 × 10(9) platelets/l representing 3·9-fold (P < 0·001) enrichment relative to whole blood. Growth factor abundance in Vivostat PRF and serum was in descending order: transforming growth factor-β1 [5·1-fold higher in PRF than serum, P < 0·001] > platelet-derived growth factor (PDGF)-AB [2·5-fold, P < 0·01] > PDGF-BB [1·6-fold, P < 0·05] > vascular endothelial growth factor > basic fibroblast growth factor [75-fold, P < 0·001]. MMP-9 was reduced 139-fold (P < 0·001) compared with serum, reflecting leucocyte depletion in PRF. The gained knowledge on platelet enrichment and biomolecular constituents may guide clinicians in their optimal use of Vivostat PRF for tissue regenerative applications. © 2013 International Society of Blood Transfusion.

Preliminary Evaluation of Platelet Rich Fibrin-Mediated Tissue Repair in Immature Canine Pulpless Teeth.

PubMed

Wang, Qi Lin; Yang, Pan Pan; Ge, Li Hong; Liu, He

2016-03-01

To evaluate the use of platelet-rich fibrin (PRF) in the regenerative therapy of immature canine permanent teeth. Eight immature premolars of beagle dogs were pulp extracted and cleaned with irrigation, then divided into two groups of empty root canals and those filled with a PRF clot. All of the eight premolars were sealed with mineral trioxide aggregate and glass ionomer cement. Two premolars were left naturally grown as a positive control. The root development was assessed radiographically and histologically after 12 weeks. The radiological findings showed greater increases in the thickness of lateral dentinal wall in the PRF group than in the vacant group. Histologically, dental-associated mineral tissue, connective tissue, and bone-like mineral tissue grew into the root canals independent of PRF clot use. The PRF was able to increase the thickness of dental-associated mineral tissue. However, the vital tissue differed from the pulp dentin complex. Our study demonstrated the feasibility of using PRF-mediated regenerative therapy in pulpless immature teeth for improving tissue repair.

Management of Facial Pyoderma Gangrenosum Using Platelet-Rich Fibrin: A Technical Report.

PubMed

Fortunato, Leonzio; Barone, Selene; Bennardo, Francesco; Giudice, Amerigo

2018-01-31

This report describes a case of local pyoderma gangrenosum that was treated with short-term immunosuppressive therapy and the topical application of platelet-rich fibrin (PRF). Medical treatment included oral corticosteroid therapy and topical treatment with PRF in solid and liquid form. This therapy initially led to the reduction of the ulcer's size and an improvement in symptoms, until the ulcer was completely healed after a few weeks. A relapse was treated with only the application of PRF to the affected tissue with excellent recovery. The efficacy of PRF as a guide for wound healing is a result of the continuous release of growth factors involved in tissue repair mechanisms. PRF has proved to be suitable for the management of facial pyoderma gangrenosum while allowing a reduction in systemic corticosteroid therapy. The ease of preparation, low cost, and outpatient use make PRF an optimal scaffold for tissue healing processes. Copyright © 2018 American Association of Oral and Maxillofacial Surgeons. Published by Elsevier Inc. All rights reserved.

THE PRENATAL PARENTAL REFLECTIVE FUNCTIONING QUESTIONNAIRE: EXPLORING FACTOR STRUCTURE AND CONSTRUCT VALIDITY OF A NEW MEASURE IN THE FINN BRAIN BIRTH COHORT PILOT STUDY.

PubMed

Pajulo, Marjukka; Tolvanen, Mimmi; Karlsson, Linnea; Halme-Chowdhury, Elina; Öst, Camilla; Luyten, Patrick; Mayes, Linda; Karlsson, Hasse

2015-01-01

Parental reflective functioning (PRF) is the capacity to focus on experience and feelings in oneself and in the child. Individual differences in PRF reportedly affect child attachment and socioemotional development. In this study, we report work on developing a questionnaire to assess PRF during pregnancy (Prenatal Parental Reflective Functioning Questionnaire; P-PRFQ). The factor structure of the 33-item version of the P-PRFQ was explored using pilot study data from the Finn Brain Birth Cohort Study (n = 124 mothers, n = 82 fathers). Construct validity was assessed against the Pregnancy Interview (PI; A. Slade, L. Grunebaum, L. Huganir, & M. Reeves, 1987, 2002, 2011) in a subsample of 29 mothers from the same pilot sample. Exploratory and confirmatory factor analysis resulted in a 14-item P-PRFQ, with three factors which seem to capture relevant aspects of prenatal parental mentalization-F1: "Opacity of mental states," F2: "Reflecting on the fetus-child," and F3: "The dynamic nature of the mental states." Functioning of the factor structure was further tested in the large cohort with 600 mothers and 600 fathers. Correlations with the PI result were high, both regarding total and factor scores of the P-PRFQ. Cost-effective tools to assess key areas of early parenting are needed for both research and clinical purposes. The 14-item P-PRFQ seems to be an applicable and promising new tool for assessing very early parental mentalizing capacity. © 2015 Michigan Association for Infant Mental Health.

In situ measurement of tissue impedance using an inductive coupling interface circuit.

PubMed

Chiu, Hung-Wei; Chuang, Jia-min; Lu, Chien-Chi; Lin, Wei-Tso; Lin, Chii-Wann; Lin, Mu-Lien

2013-06-01

In this work, a method of an inductive coupling impedance measurement (ICIM) is proposed for measuring the nerve impedance of a dorsal root ganglion (DRG) under PRF stimulation. ICIM provides a contactless interface for measuring the reflected impedance by an impedance analyzer with a low excitation voltage of 7 mV. The paper develops a calibration procedure involving a 50-Ω reference resistor to calibrate the reflected resistance for measuring resistance of the nerve in the test. A de-embedding technique to build the equivalent transformer circuit model for the ICIM circuit is also presented. A batteryless PRF stimulator with ICIM circuit demonstrated good accuracy for the acute measurement of DRG impedance both in situ and in vivo. Besides, an in vivo animal experiment was conducted to show that the effectiveness of pulsed radiofrequency (PRF) stimulation in relieving pain gradually declined as the impedance of the stimulated nerve increased. The experiment also revealed that the excitation voltage for measuring impedance below 25 mV can prevent the excitation of a nonlinear response of DRG.

Micro-computed tomography and histomorphometric analysis of the effects of platelet-rich fibrin on bone regeneration in the rabbit calvarium.

PubMed

Acar, Ahmet Hüseyin; Yolcu, Ümit; Gül, Mehmet; Keleş, Ali; Erdem, Necip Fazıl; Altundag Kahraman, Sevil

2015-04-01

The present study aimed to investigate the effectiveness of platelet-rich fibrin (PRF) on bone regeneration when used alone or in combination with hydroxyapatite (HA)/beta-tricalcium phosphate (βTCP). In this study, 20 New Zealand white rabbits were used and four calvarial defects were prepared in each animal. PRF, Straumann(®) Bone Ceramic (SBC), or PRF+SBC was applied to the defects; one defect was left untreated as a control. Ten rabbits were sacrificed at week 4 (T1) and 10 at week 8 (T2). After micro-computed tomography (micro-CT) scanning, the samples were sent for histological and histomorphometric analysis to evaluate and compare the volume and area of regenerated bone. Histomorphometric and micro-CT analysis showed that both PRF and SBC significantly increased bone regeneration at T1 and T2 (P<0.01). When PRF was used in combination with HA/βTCP, a further significant increase in new bone formation was observed at T1 and T2 compared with that when PRF or SBC was used alone (P<0.01). PRF has a positive effect on bone formation when used alone and in combination with HA/βTCP. Copyright © 2014 Elsevier Ltd. All rights reserved.

Platelet-Rich Fibrin Accelerates Skin Wound Healing in Diabetic Mice.

PubMed

Ding, Yinjia; Cui, Lei; Zhao, Qiming; Zhang, Weiqiang; Sun, Huafeng; Zheng, Lijun

2017-09-01

Diabetic foot ulcers (DFUs) are associated with an increased risk of secondary infection and amputation. Platelet-rich fibrin (PRF), a platelet and leukocyte concentrate containing several cytokines and growth factors, is known to promote wound healing. However, the effect of PRF on diabetic wound healing has not been adequately investigated. The aim of the study was to investigate the effect of PRF on skin wound healing in a diabetic mouse model. Platelet-rich fibrin was prepared from whole blood of 8 healthy volunteers. Two symmetrical skin wounds per mouse were created on the back of 16 diabetic nude mice. One of the 2 wounds in each mouse was treated with routine dressings (control), whereas the other wound was treated with PRF in addition to routine dressings (test), each for a period of 14 days. Skin wound healing rate was calculated.Use of PRF was associated with significantly improved skin wound healing in diabetic mice. On hematoxylin and eosin and CD31 staining, a significant increase in the number of capillaries and CD31-positive cells was observed, suggesting that PRF may have promoted blood vessel formation in the skin wound. In this study, PRF seemed to accelerate skin wound healing in diabetic mouse models, probably via increased blood vessel formation.

Effects of platelet-rich fibrin and piezosurgery on impacted mandibular third molar surgery outcomes.

PubMed

Uyanık, Lokman Onur; Bilginaylar, Kani; Etikan, İlker

2015-07-26

The aim of this study was the comparision of postoperative outcomes in impacted mandibular third molars that were treated using either platelet-rich fibrin (PRF), a combination of PRF and piezosurgery, or conventional rotatory osteotomy. The study included 20 patients; 40 extractions of impacted mandibular third molars were performed. Patients were divided into two main groups. In group A (n = 20), traditional surgery was performed on one side (Group 1, n = 10); traditional surgery was performed, and PRF was administered to the extracted socket on the other side of same patient (Group 2, n = 10). In group B (n = 20), on one side, piezosurgery was used for osteotomy, and PRF was administered (Group 3, n = 10); on the other side of same patient, traditional surgery was performed (Group 4, n = 10). Parameters assessed at baseline for each patient included pain, the number of analgesics taken, trismus, and cheek swelling. These variables were also assessed on postoperative days 1, 2, 3, and 7. Statistical analysis revealed a significant reduction in postoperative pain (sum of 1(st), 2(nd), 3(rd) and 7(th) days) and trismus (on postoperative day 1) in group 2 (traditional surgery + PRF group), and in postoperative pain, the number of analgesics taken (sum of 1(st), 2(nd),3(rd) and 7(th) days) and trismus (on postoperative day 1) in group 3 (piezosurgery + PRF group) compared to groups 1 and 4 (traditional surgery groups), (p ≤ 0.05). However, swelling on postoperative days 1, 3, and 7 did not differ among the groups (p > 0.05). Only difference was on second day between groups 1-4 and 2-4 (p ≤ 0.05). The results of our study have shown that the use of PRF with traditional surgery and PRF combined with piezosurgery significantly reduced pain during the postoperative period. In addition, PRF in combination with piezosurgery significantly decreased the number of analgesics taken. Both operations also significantly decreased trismus 24 h after the surgery. As a result of this study, PRF and combination use of PRF and piezosurgery have positive effects in reducing postoperative outcomes after impacted third molar surgery.

Does the Addition of Bone Morphogenetic Protein 2 to Platelet-Rich Fibrin Improve Healing After Treatment for Medication-Related Osteonecrosis of the Jaw?

PubMed

Park, Jung-Hyun; Kim, Jin-Woo; Kim, Sun-Jong

2017-06-01

To investigate the effect of the addition of bone morphogenetic protein 2 (BMP-2) to leukocyte-rich and platelet-rich fibrin (L-PRF) on the treatment of medication-related osteonecrosis of the jaws (MRONJ), this study compared the healing outcome of combined use of BMP-2 and L-PRF with single use of L-PRF. Of 55 patients who were diagnosed with MRONJ, 25 were treated with L-PRF alone and 30 were treated with L-PRF and recombinant human BMP-2. For each patient, surgical sites were evaluated postoperatively at 4 and 16 weeks. Associations between the treatment method and the resolution of MRONJ were analyzed with the adjustment of patient-specific factors that may influence the treatment outcome. At 4 and 16 weeks postoperatively, patients with MRONJ who were treated with both L-PRF and BMP-2 showed favorable outcomes with complete resolution of the lesions, which was statistically significant compared with that of the therapy using L-PRF alone (P = .028). Therefore, the additional use of BMP-2 considerably improved MRONJ healing. Among patient-specific factors, the existence of a bacterial colony in the biopsy specimen was a significant factor that negatively affected disease resolution (P = .017). The combined use of BMP-2 and L-PRF leads to the early resolution of MRONJ; thus patients who need to continue antiresorptive therapy may benefit from the combined regimen. Copyright © 2016 American Association of Oral and Maxillofacial Surgeons. Published by Elsevier Inc. All rights reserved.

Pulsed Radiofrequency: A Management Option for Recurrent Trigeminal Neuralgia Following Radiofrequency Thermocoagulation.

PubMed

Liao, Chenlong; Visocchi, Massimiliano; Yang, Min; Liu, Pengfei; Li, Shiting; Zhang, Wenchuan

2017-01-01

Pain relief comparable with radiofrequency thermocoagulation (RFT) alone and fewer side effects than RFT have been achieved by combination treatment with pulsed radiofrequency (PRF) and short-duration RFT in trigeminal neuralgia (TN). We report the successful management of recurrent TN after RFT with single PRF in 2 patients. The RFT treatment was performed in 2-3 cycles for each division, with the lesion setting at 75°C-80°C for 90 seconds. The PRF treatment was applied for 120 seconds, with a generator output of 45 V, not exceeding a temperature of 42°C at the tip of the electrode. In case 1, pain relief was immediately achieved by RFT (75°C for 90 seconds), with moderate hypesthesia. Relapse of the triggered pain occurred 6 months later, and PRF was then applied. Long-term (18 months) pain relief without any additional pharmacologic or other treatment was reported. In case 2, a second RFT treatment at a higher temperature (80°C) was performed after recurrence after the first RFT within a week. Accompanied by worse hypesthesia, complete pain relief lasted for 6 months until the recurrence of pain was triggered by toothbrushing. PRF was then applied, and complete analgesia with long-term follow-up (28 months) was achieved. The PRF treatment for recurrent TN after RFT in this study could be viewed as a combination of PRF and RFT treatments in succession. Therefore, PRF and RFT should be considered to be complementary rather than alternative in the management of TN. Copyright © 2016 Elsevier Inc. All rights reserved.

Long palatal connective tissue rolled pedicle graft with demineralized freeze-dried bone allograft plus platelet-rich fibrin combination: A novel technique for ridge augmentation - Three case reports

PubMed Central

Reddy, Pathakota Krishnajaneya; Bolla, Vijayalakshmi; Koppolu, Pradeep; Srujan, Peruka

2015-01-01

Replacement of missing maxillary anterior tooth with localized residual alveolar ridge defect is challenging, considering the high esthetic demand. Various soft and hard tissue procedures were proposed to correct alveolar ridge deformities. Novel techniques have evolved in treating these ridge defects to improve function and esthetics. In the present case reports, a novel technique using long palatal connective tissue rolled pedicle graft with demineralized freeze-dried bone allografts (DFDBAs) plus Platelet-rich fibrin (PRF) combination was proposed to correct the Class III localized anterior maxillary anterior alveolar ridge defect. The present technique resulted in predictable ridge augmentation, which can be attributed to the soft and hard tissue augmentation with a connective tissue pedicle and DFDBA plus PRF combination. This technique suggests a variation in roll technique with DFDBA plus PRF and appears to promise in gaining predictable volume in the residual ridge defect and can be considered for the treatment of moderate to severe maxillary anterior ridge defects. PMID:26015679

Characterization of immune cells and perforin mutations in familiar venous thromboembolism.

PubMed

Duan, Qianglin; Lv, Wei; Yang, Minjun; Yang, Fan; Zhu, Yongqiang; Kang, Hui; Song, Haoming; Wang, Shengyue; Dong, Hui; Wang, Lemin

2015-01-01

This study was to carry out exome sequencing in a Han Chinese family with venous thromboembolism. Three venous thromboembolism (VTE) patients and five members from a Han Chinese family were evaluated by exome sequencing. Among the 3 VTE patients, mutations of 2 genes including PRF1 and HTR2A were identified and predicted to be functionally damaged to their encoded proteins. In addition, the PRF1 mutation and the HTR2A mutation identified in our study were absent in 100 non-related controls, indicating that venous thromboembolism has a genetic component. The R357W mutation is located in the membrane attack complex/perforin domain of PRF1 protein, which exists in both the perforin. The steps of killing foreign or pathological antigen cells by NK cells, CD8 (+)T cells and the membrane attack complex include membrane perforation and release of the granzyme, either of which is abnormal can lead to immune dysfunction. The mutations of immune related genes in familial VTE might provide new understanding of the pathogenesis of familial venous thromboembolism.

Influence of the association between platelet-rich fibrin and bovine bone on bone regeneration. A histomorphometric study in the calvaria of rats.

PubMed

Oliveira, M R; deC Silva, A; Ferreira, S; Avelino, C C; Garcia, I R; Mariano, R C

2015-05-01

This study aimed to investigate the effects of platelet-rich fibrin (PRF) associated or not with Bio-Oss on bone defects in the calvaria of rats. A critical-size defect of 5-mm diameter was performed in the calvaria of 48 rats. These animals were divided into six groups of eight animals each, according to the treatment received: homogeneous clot, autogenous clot, autogenous PRF, homogeneous PRF, Bio-Oss, or Bio-Oss associated with PRF. The animals were euthanized after 30 or 60 days. Bone regeneration was evaluated by histomorphometric analysis. The highest mean percentages of new bone formation at 30 days (54.05% ± 5.78) and 60 days (63.58% ± 5.78) were observed in the Bio-Oss associated with PRF group; in particular, the percentage of new bone at 30 days was significantly higher than that of all of the other groups (P<0.01). At 60 days, the Bio-Oss associated with PRF (63.58% ± 5.78) and Bio-Oss (57.34% ± 5.78) groups had similar results, and both showed a statistical difference compared to the other groups. PRF had a positive effect on bone regeneration only when associated with Bio-Oss. Copyright © 2014 International Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.

The Synergistic Effect of Leukocyte Platelet-Rich Fibrin and Micrometer/Nanometer Surface Texturing on Bone Healing around Immediately Placed Implants: An Experimental Study in Dogs

PubMed Central

Neiva, Rodrigo F.; Gil, Luiz Fernando; Tovar, Nick; Janal, Malvin N.; Marao, Heloisa Fonseca; Pinto, Nelson; Coelho, Paulo G.

2016-01-01

Aims. This study evaluated the effects of L-PRF presence and implant surface texture on bone healing around immediately placed implants. Methods. The first mandibular molars of 8 beagle dogs were bilaterally extracted, and implants (Blossom™, Intra-Lock International, Boca Raton, FL) were placed in the mesial or distal extraction sockets in an interpolated fashion per animal. Two implant surfaces were distributed per sockets: (1) dual acid-etched (DAE, micrometer scale textured) and (2) micrometer/nanometer scale textured (Ossean™ surface). L-PRF (Intraspin system, Intra-Lock International) was placed in a split-mouth design to fill the macrogap between implant and socket walls on one side of the mandible. The contralateral side received implants without L-PRF. A mixed-model ANOVA (at α = 0.05) evaluated the effect of implant surface, presence of L-PRF, and socket position (mesial or distal), individually or in combination on bone area fraction occupancy (BAFO). Results. BAFO values were significantly higher for the Ossean relative to the DAE surface on the larger mesial socket. The presence of L-PRF resulted in higher BAFO. The Ossean surface and L-PRF presence resulted in significantly higher BAFO. Conclusion. L-PRF and the micro-/nanometer scale textured surface resulted in increased bone formation around immediately placed implants. PMID:28042577

Individualized titanium mesh combined with platelet-rich fibrin and deproteinized bovine bone: A new approach for challenging augmentation.

PubMed

Lorenz, Jonas; Al-Maawi, Sarah; Sader, Robert; Ghanaati, Shahram

2018-05-21

Autologous bone transfer is regarded as the gold standard for ridge augmentation before dental implantation, especially in severe bony defects caused by tumor resection or atrophy. In addition to the advantages of autologous bone, transplantation has several disadvantages, such as secondary operation, increased morbidity and pain. The present study reports, for the first time, a combination of a xenogeneic bone substitute (BO) with platelet-rich fibrin (PRF), which is a fully autologous blood concentrate derived from the patient's own peripheral blood by centrifugation. Solid A-PRF+TM and liquid i-PRFTM together with an individualized 3-D planned titanium mesh were used for reconstruction of a severe tumor-related bony defect within the mandible of a former head and neck cancer patient. The BO enriched with regenerative components from PRF allowed the reconstruction of the mandibular resective defect under the 3-D-mesh without autologous bone transplantation. Complete rehabilitation and restoration of the patient´s oral function were achieved. Histological analysis of extracted bone biopsies confirmed that the new bone within the augmented region originated from the residual bone. Within the limitations of the presented case, the applied concept appears to be a promising approach to increase the regenerative capacity of a bone substitute material, as well as decrease the demand for autologous bone transplantation, even in cases in which autologous bone is considered the golden standard. PRF can be considered a reliable source for increasing the biological capacities of bone substitute materials.

Modeling and Analysis of Gated, Pulsed RFI and Its Effect on GPS Receivers: Analysis of Average Cycle Slip Rate and Average Bit Error Probability

DTIC Science & Technology

2014-04-01

as a function of the pulse duty cycle PDC is [1]: ∆C/N0 = 20 log(1 − PDC ) (1) PDC , PW × PRF (2) where PW represents the pulse width (sec) and PRF is...corresponding degradation in C/N0 should now be modeled as ∆C/N0 = 20 log(1 − PDCLIM) (3) PDCLIM , PDC τobs TTC . (4) The degradation model of Eqn. 3 and 4...cycle that is the product of the duty cycle of the pulsed waveform ( PDC ) and the duty cycle of the of the gating waveform (τobs/TTC). While such a model

Personality Correlates of Self-Report, Role-Playing, and In Vivo Measures of Assertiveness.

ERIC Educational Resources Information Center

Green, Samuel B.; And Others

1979-01-01

Undergraduates completed self-report inventories of assertiveness, participated in behavior role-playing tasks and in vivo measures of assertiveness, and completed the Personality Research Form E (PRF-E). Of 22 PRF-E scales, 11 had at least one significant correlation with assertiveness measures. Some composites of PRF-E scales were related to…

Novel genes related to nodulation, secretion systems, and surface structures revealed by a genome draft of Rhizobium tropici strain PRF 81.

PubMed

Pinto, Fabiana G S; Chueire, Ligia M O; Vasconcelos, Ana Tereza R; Nicolás, Marisa F; Almeida, Luiz G P; Souza, Rangel C; Menna, Pâmela; Barcellos, Fernando G; Megías, Manuel; Hungria, Mariangela

2009-05-01

Rhizobium tropici is representative of the diversity of tropical rhizobia, besides comprising strains very effective in fixing N(2) in symbiosis with the common bean (Phaseolus vulgaris L.). The genome of a Brazilian commercial inoculant R. tropici strain (PRF 81, =SEMIA 4088), estimated at 7.85 Mb, was analyzed through a total of 9,026 shotgun reads, assembled in 1,668 phrap contigs, and covering approximately 30% of the genome. Annotation identified 2,135 coding DNA sequences (CDS), and only 57.2% have possible functions. The genome comprises a mosaic of genes, with CDS showing the highest similarities with 134 microorganisms, none of which represents more than 19% of the CDS with putative known functions. The high saprophytic capacity of PRF 81 may reside in a variety of genes related to transport, biodegradation of xenobiotics, defense, and secretion proteins, many of which were reported for the first time in the present study. Novelty was also found in nodulation (nodG, a double nodIJ system, nodT, nolF, nolG) and capsular polysaccharide genes, showing stronger similarities with Sinorhizobium (=Ensifer) than with the main symbionts of the common bean -- R. etli and R. leguminosarum -- suggesting that the original host of R. tropici might be another tropical legume or emphasizing the highly promiscuous nature of this rhizobial species.

Imaging the Moho beneath Sedimentary Basins: A Comparative Study of Virtual Deep Seismic Sounding (VDSS) and P Wave Receiver Functions (PRF)

NASA Astrophysics Data System (ADS)

Liu, T.; Klemperer, S. L.; Yu, C.; Ning, J.

2017-12-01

In the past decades, P wave receiver functions (PRF) have been routinely used to image the Moho, although it is well known that PRFs are susceptible to contamination from sedimentary multiples. Recently, Virtual Deep Seismic Sounding (VDSS) emerged as a novel method to image the Moho. However, despite successful applications of VDSS on multiple datasets from different areas, how sedimentary basins affect the waveforms of post-critical SsPmp, the Moho reflection phase used in VDSS, is not widely understood. Here, motivated by a dataset collected in the Ordos plateau, which shows distinct effects of sedimentary basins on SsPmp and Pms waveforms, we use synthetic seismograms to study the effects of sedimentary basins on SsPmp and Pms, the phases used in VDSS and PRF respectively. The results show that when the sedimentary thickness is on the same order of magnitude as the dominant wavelength of the incident S wave, SsPmp amplitude decreases significantly with S velocity of the sedimentary layer, whereas increasing sedimentary thickness has little effect in SsPmp amplitude. Our explanation is that the low S velocity layer at the virtual source reduces the incident angle of S wave at the free surface, thus decreases the S-to-P reflection coefficient at the virtual source. In addition, transmission loss associated with the bottom of sedimentary basins also contributes to reducing SsPmp amplitude. This explains not only our observations from the Ordos plateau, but also observations from other areas where post-critical SsPmp is expected to be observable, but instead is too weak to be identified. As for Pms, we observe that increasing sedimentary thickness and decreasing sedimentary velocities both can cause interference between sedimentary multiples and Pms, rendering the Moho depths inferred from Pms arrival times unreliable. The reason is that although Pms amplitude does not vary with sedimentary thickness or velocities, as sedimentary velocities decrease and thickness grows, the sedimentary multiples will become stronger and arrive later, and will eventually interfere with Pms. In summary, although both VDSS and PRF are subject to sedimentary effects, when the sedimentary velocity is relatively high, we can still expect VDSS to give reasonable estimations of Moho depths, whereas PRF in such cases might be too noisy to use.

Classification of platelet concentrates: from pure platelet-rich plasma (P-PRP) to leucocyte- and platelet-rich fibrin (L-PRF).

PubMed

Dohan Ehrenfest, David M; Rasmusson, Lars; Albrektsson, Tomas

2009-03-01

The topical use of platelet concentrates is recent and its efficiency remains controversial. Several techniques for platelet concentrates are available; however, their applications have been confusing because each method leads to a different product with different biology and potential uses. Here, we present classification of the different platelet concentrates into four categories, depending on their leucocyte and fibrin content: pure platelet-rich plasma (P-PRP), such as cell separator PRP, Vivostat PRF or Anitua's PRGF; leucocyte- and platelet-rich plasma (L-PRP), such as Curasan, Regen, Plateltex, SmartPReP, PCCS, Magellan or GPS PRP; pure plaletet-rich fibrin (P-PRF), such as Fibrinet; and leucocyte- and platelet-rich fibrin (L-PRF), such as Choukroun's PRF. This classification should help to elucidate successes and failures that have occurred so far, as well as providing an objective approach for the further development of these techniques.

Management of radicular cysts using platelet-rich fibrin and bioactive glass: a report of two cases.

PubMed

Zhao, Jiing-Huei; Tsai, Chung-Hung; Chang, Yu-Chao

2014-07-01

Platelet-rich fibrin (PRF) created by Choukroun's protocol concentrates most platelets and leukocytes from a blood harvest into a single autologous fibrin biomaterial. However, no current data is available concerning the use of PRF for the treatment of periapical lesions. Two cases of radicular cysts were reported using an interdisciplinary approach, including regular endodontic therapy followed by surgical management with PRF and bioactive glass. Two cases of radicular cysts presented as an incidental radiographic finding, appearing as an apical radiolucency with well-circumscribed sclerotic borders. After regular endodontic retreatment, cystic lining/granulation tissues were enucleated and the periradicular bony defect was grafted using PRF and bioactive glass. Then, PRF was applied to serve as a membrane over the grafted defects. Recall periapical radiographs of Case 1 and cone beam computer tomography of Case 2 showed satisfactory healing of the periapical pathosis. In Case 2, the bony defect appeared completely healed at 4 months surgical reentry and the new bone was clinically very dense and mature. The results of these case reports show that the combination of PRF and bioactive glass is an effective modality of regenerative treatment for radicular cysts. Copyright © 2012. Published by Elsevier B.V.

Effects of leukocyte-platelet rich fibrin on postoperative complications of direct sinus lifting.

PubMed

Gurler, Gokhan; Delilbasi, Cagri

2016-08-01

Blood products have been widely used in soft tissue and bone regeneration in oral and maxillofacial surgery. The purpose of this study is to evaluate the effects of leukocyte-platelet rich fibrin (L-PRF) following direct sinus lifting procedure. Twenty-eight patients were included in the study. Direct sinus lifting was performed via lateral window approach under conscious sedation and local anesthesia. Bony window and sinus floor elevation were performed using piezosurgery device. Two groups were formed. In the first group an allogenous bone graft and L-PRF mixture was used as grafting material. The L-PRF membrane was used to close the lateral window. In the second group, only allogenous bone was used for grafting and resorbable collagen membrane was used to close the lateral window. Pain, swelling, sleeping, eating, phonetics, activities of daily living, missed work days and soft tissue healing were evaluated postoperatively. Data of 24 patients were evaluated. Improvements were seen in the studied parameters in the L-PRF group; however, the difference was not significant between the two groups (P>0.05). The use of L-PRF and allogenous bone graft in combination with L-PRF membrane does not significantly improve postoperative complications following direct sinus lifting.

Three-dimensional architecture and cell composition of a Choukroun's platelet-rich fibrin clot and membrane.

PubMed

Dohan Ehrenfest, David M; Del Corso, Marco; Diss, Antoine; Mouhyi, Jaafar; Charrier, Jean-Baptiste

2010-04-01

Platelet-rich fibrin (PRF; Choukroun's technique) is a second-generation platelet concentrate for surgical use. This easy protocol allows the production of leukocyte and platelet-rich fibrin clots and membranes starting from 10-ml blood samples. The purposes of this study were to determine the cell composition and three-dimensional organization of this autologous biomaterial and to evaluate the influence of different collection tubes (dry glass or glass-coated plastic tubes) and compression procedures (forcible or soft) on the final PRF-membrane architecture. After centrifugation, blood analyses were performed on the residual waste plasmatic layers after collecting PRF clots. The PRF clots and membranes were processed for examination by light microscopy and scanning electron microscopy. Approximately 97% of the platelets and >50% of the leukocytes were concentrated in the PRF clot and showed a specific three-dimensional distribution, depending on the centrifugation forces. Platelets and fibrin formed large clusters of coagulation in the first millimeters of the membrane beyond the red blood cell base. The fibrin network was very mature and dense. Moreover, there was no significant difference in the PRF architecture between groups using the different tested collection tubes and compression techniques, even if these two parameters could have influenced the growth factor content and biologic matrix properties. The PRF protocol concentrated most platelets and leukocytes from a blood harvest into a single autologous fibrin biomaterial. This protocol offers reproducible results as long as the main production principles are respected.

Evaluation of the efficacy of platelet-rich plasma and platelet-rich fibrin in alveolar defects after removal of impacted bilateral mandibular third molars

PubMed Central

Doiphode, Amol M.; Hegde, Prashanth; Mahindra, Uma; Santhosh Kumar, S. M.; Tenglikar, Pavan D.; Tripathi, Vivek

2016-01-01

Aim and Objectives: This study attempted the evaluation of the efficacy of platelet-rich plasma (PRP) and platelet-rich fibrin (PRF) in alveolar defects after removal of bilateral mandibular third molars. Materials and Methods: A total of 30 patients reporting to Department of Oral and Maxillofacial Surgery and having bilateral mandibular third molar impaction in both male and female aged between 18 and 30 years were included in this study. PRF and PRP were placed in extraction site and recalled at 2nd, 4th, and 6th month postoperatively. Data were statistically analyzed using IBM SPSS software for Windows, version 19.0. IBM Corp., Armonk, NY, USA. Results: This study showed decreased probing depth in PRF group compared to PRP and control one. This signifies a better soft tissue healing of extraction sockets with PRF as compared to the PRP and the control group and increase in the bone density highlights the use of PRP and PRF certainly as a valid method in inducing hard tissue regeneration. Conclusion: This study indicates a definite improvement in the periodontal health distal to second molar after third molar surgery in cases treated with PRF as compared to the PRP group and control group. Hence, PRP and PRF can be incorporated as an adjunct to promote wound healing and osseous regeneration in mandibular third molar extraction sites. PMID:27195227

Application of distance-dependent resolution compensation and post-reconstruction filtering for myocardial SPECT

NASA Astrophysics Data System (ADS)

Hutton, Brian F.; Lau, Yiu H.

1998-06-01

Compensation for distance-dependent resolution can be directly incorporated in maximum likelihood reconstruction. Our objective was to examine the effectiveness of this compensation using either the standard expectation maximization (EM) algorithm or an accelerated algorithm based on use of ordered subsets (OSEM). We also investigated the application of post-reconstruction filtering in combination with resolution compensation. Using the MCAT phantom, projections were simulated for data, including attenuation and distance-dependent resolution. Projection data were reconstructed using conventional EM and OSEM with subset size 2 and 4, with/without 3D compensation for detector response (CDR). Also post-reconstruction filtering (PRF) was performed using a 3D Butterworth filter of order 5 with various cutoff frequencies (0.2-). Image quality and reconstruction accuracy were improved when CDR was included. Image noise was lower with CDR for a given iteration number. PRF with cutoff frequency greater than improved noise with no reduction in recovery coefficient for myocardium but the effect was less when CDR was incorporated in the reconstruction. CDR alone provided better results than use of PRF without CDR. Results suggest that using CDR without PRF, and stopping at a small number of iterations, may provide sufficiently good results for myocardial SPECT. Similar behaviour was demonstrated for OSEM.

Effects of an injectable platelet-rich fibrin on osteoblast behavior and bone tissue formation in comparison to platelet-rich plasma.

PubMed

Wang, Xuzhu; Zhang, Yufeng; Choukroun, Joseph; Ghanaati, Shahram; Miron, Richard J

2018-01-01

Platelet-rich plasma (PRP) has been utilized for many years as a regenerative agent capable of inducing vascularization of various tissues using blood-derived growth factors. Despite this, drawbacks mostly related to the additional use of anti-coagulants found in PRP have been shown to inhibit the wound healing process. For these reasons, a novel platelet concentrate has recently been developed with no additives by utilizing lower centrifugation speeds. The purpose of this study was therefore to investigate osteoblast behavior of this novel therapy (injectable-platelet-rich fibrin; i-PRF, 100% natural with no additives) when compared to traditional PRP. Human primary osteoblasts were cultured with either i-PRF or PRP and compared to control tissue culture plastic. A live/dead assay, migration assay as well as a cell adhesion/proliferation assay were investigated. Furthermore, osteoblast differentiation was assessed by alkaline phosphatase (ALP), alizarin red and osteocalcin staining, as well as real-time PCR for genes encoding Runx2, ALP, collagen1 and osteocalcin. The results showed that all cells had high survival rates throughout the entire study period irrespective of culture-conditions. While PRP induced a significant 2-fold increase in osteoblast migration, i-PRF demonstrated a 3-fold increase in migration when compared to control tissue-culture plastic and PRP. While no differences were observed for cell attachment, i-PRF induced a significantly higher proliferation rate at three and five days when compared to PRP. Furthermore, i-PRF induced significantly greater ALP staining at 7 days and alizarin red staining at 14 days. A significant increase in mRNA levels of ALP, Runx2 and osteocalcin, as well as immunofluorescent staining of osteocalcin was also observed in the i-PRF group when compared to PRP. In conclusion, the results from the present study favored the use of the naturally-formulated i-PRF when compared to traditional PRP with anti-coagulants. Further investigation into the direct role of fibrin and leukocytes contained within i-PRF are therefore warranted to better elucidate their positive role in i-PRF on tissue wound healing.

Comparison between PRP, PRGF and PRF: lights and shadows in three similar but different protocols.

PubMed

Giannini, S; Cielo, A; Bonanome, L; Rastelli, C; Derla, C; Corpaci, F; Falisi, G

2015-01-01

The main goal of the modern surgery is to get a low invasiveness and a high rate of clinical healing: in the last years, it has been introduced the concept of a "regenerative surgery", and many techniques has been widely described in the literature. The most used are PRP, PRGF and PRF techniques. Aim of this research is to compare the three protocol of PRP, PRF and PRGF in their essential features, so to suggest to the practitioners the best blood product to use in the regenerative surgery. Among the advantages that shows the PRF, compared to PRP and PRGF, we can cite a greater simplicity of production for the absence of manipulation that leads to a reduced possibility of alteration of the protocol due to an error of the operator. The special texture of the PRF and its biological features shows clearly an interesting surgical versatility and all the characteristics that can support a faster tissues regeneration and high-quality clinical outcomes.

Central nervous system activity of the proanthocyanidin-rich fraction obtained from Croton celtidifolius in rats.

PubMed

Moreira, Eduardo L G; Rial, Daniel; Duarte, Filipe S; de Carvalho, Cristiane Ribeiro; Horst, Heros; Pizzolatti, Moacir G; Prediger, Rui D S; Ribeiro-do-Valle, Rosa Maria

2010-08-01

The aim of the present study was to evaluate the possible neurobehavioural effects in rats of the proanthocyanidin-rich fraction (PRF) isolated from the bark of Croton celtidifolius (Euphorbiaceae). Adult Wistar rats were treated with the PRF (0.3-30 mg/kg) and evaluated in different behavioural paradigms classically used for the screening of drugs with psychoactive effects. Acute intraperitoneal (i.p.) administration of PRF decreased spontaneous locomotor activity (open field arena and activity cage), enhanced the duration of ethyl ether-induced hypnosis, increased the latency to the first convulsion induced by pentylenetetrazole (60 mg/kg, i.p.) and attenuated apomorphine-induced (0.5 mg/kg, i.p.) stereotyped behaviour. In lower doses, PRF (0.3 or 3 mg/kg, i.p.) increased the frequency of open arm entries in the elevated plus-maze test. The present findings suggest that the systemic administration of PRF induces a wide spectrum of behavioural alterations in rats, consistent with the putative existence of hypnosedative, anticonvulsant and anxiolytic compounds.

Platelet rich fibrin in jaw defects

NASA Astrophysics Data System (ADS)

Nica, Diana; Ianes, Emilia; Pricop, Marius

2016-03-01

Platelet rich fibrin (PRF) is a tissue product of autologous origin abundant in growth factors, widely used in regenerative procedures. Aim of the study: Evaluation of the regenerative effect of PRF added in the bony defects (after tooth removal or after cystectomy) Material and methods: The comparative nonrandomized study included 22 patients divided into 2 groups. The first group (the test group) included 10 patients where the bony defects were treated without any harvesting material. The second group included 12 patients where the bony defects were filled with PRF. The bony defect design was not critical, with one to two walls missing. After the surgeries, a close clinically monitoring was carried out. The selected cases were investigated using both cone beam computer tomography (CBCT) and radiographic techniques after 10 weeks postoperatively. Results: Faster bone regeneration was observed in the bony defects filled with PRF comparing with the not grafted bony defects. Conclusions: PRF added in the bony defects accelerates the bone regeneration. This simplifies the surgical procedures and decreases the economic costs.

Evaluation of the performance of quantitative detection of the Listeria monocytogenes prfA locus with droplet digital PCR.

PubMed

Witte, Anna Kristina; Fister, Susanne; Mester, Patrick; Schoder, Dagmar; Rossmanith, Peter

2016-11-01

Fast and reliable pathogen detection is an important issue for human health. Since conventional microbiological methods are rather slow, there is growing interest in detection and quantification using molecular methods. The droplet digital polymerase chain reaction (ddPCR) is a relatively new PCR method for absolute and accurate quantification without external standards. Using the Listeria monocytogenes specific prfA assay, we focused on the questions of whether the assay was directly transferable to ddPCR and whether ddPCR was suitable for samples derived from heterogeneous matrices, such as foodstuffs that often included inhibitors and a non-target bacterial background flora. Although the prfA assay showed suboptimal cluster formation, use of ddPCR for quantification of L. monocytogenes from pure bacterial cultures, artificially contaminated cheese, and naturally contaminated foodstuff was satisfactory over a relatively broad dynamic range. Moreover, results demonstrated the outstanding detection limit of one copy. However, while poorer DNA quality, such as resulting from longer storage, can impair ddPCR, internal amplification control (IAC) of prfA by ddPCR, that is integrated in the genome of L. monocytogenes ΔprfA, showed even slightly better quantification over a broader dynamic range. Graphical Abstract Evaluating the absolute quantification potential of ddPCR targeting Listeria monocytogenes prfA.

Advanced platelet-rich fibrin: a new concept for cell-based tissue engineering by means of inflammatory cells.

PubMed

Ghanaati, Shahram; Booms, Patrick; Orlowska, Anna; Kubesch, Alica; Lorenz, Jonas; Rutkowski, Jim; Landes, Constantin; Sader, Robert; Kirkpatrick, Cj; Choukroun, Joseph

2014-12-01

Choukroun's platelet-rich fibrin (PRF) is obtained from blood without adding anticoagulants. In this study, protocols for standard platelet-rich fibrin (S-PRF) (2700 rpm, 12 minutes) and advanced platelet-rich fibrin (A-PRF) (1500 rpm, 14 minutes) were compared to establish by histological cell detection and histomorphometrical measurement of cell distribution the effects of the centrifugal force (speed and time) on the distribution of cells relevant for wound healing and tissue regeneration. Immunohistochemistry for monocytes, T and B -lymphocytes, neutrophilic granulocytes, CD34-positive stem cells, and platelets was performed on clots produced from four different human donors. Platelets were detected throughout the clot in both groups, although in the A-PRF group, more platelets were found in the distal part, away from the buffy coat (BC). T- and B-lymphocytes, stem cells, and monocytes were detected in the surroundings of the BC in both groups. Decreasing the rpm while increasing the centrifugation time in the A-PRF group gave an enhanced presence of neutrophilic granulocytes in the distal part of the clot. In the S-PRF group, neutrophils were found mostly at the red blood cell (RBC)-BC interface. Neutrophilic granulocytes contribute to monocyte differentiation into macrophages. Accordingly, a higher presence of these cells might be able to influence the differentiation of host macrophages and macrophages within the clot after implantation. Thus, A-PRF might influence bone and soft tissue regeneration, especially through the presence of monocytes/macrophages and their growth factors. The relevance and feasibility of this tissue-engineering concept have to be proven through in vivo studies.

Potential dental pulp revascularization and odonto-/osteogenic capacity of a novel transplant combined with dental pulp stem cells and platelet-rich fibrin.

PubMed

Chen, Yong-Jin; Zhao, Yin-Hua; Zhao, Ya-Juan; Liu, Nan-Xia; Lv, Xin; Li, Qiang; Chen, Fa-Ming; Zhang, Min

2015-08-01

Our aim is to investigate the cytobiological effects of autologous platelet-rich fibrin (PRF) on dental pulp stem cells (DPSCs) and to explore the ectopic and orthotopic possibilities of dental pulp revascularization and pulp-dentin complex regeneration along the root canal cavities of the tooth by using a novel tissue-engineered transplant composed of cell-sheet fragments of DPSCs and PRF granules. Canine DPSCs were isolated and characterized by assaying their colony-forming ability and by determining their cell surface markers and osteogenic/adipogenic differentiation potential. The biological effects of autologous PRF on DPSCs, including cell proliferation, alkaline phosphatase (ALP) activity and odonto-/osteogenic gene expression, were then investigated and quantified. A novel transplant consisting of cell-sheet fragments of DPSCs and PRF granules was adopted to regenerate pulp-dentin-like tissues in the root canal, both subcutaneously in nude mice and in the roots of canines. PRF promoted the proliferation of DPSCs in a dose- and time-dependent manner and induced the differentiation of DPSCs to odonto-/osteoblastic fates by increasing the expression of the Alp, Dspp, Dmp1 and Bsp genes. Transplantation of the DPSC/PRF construct led both to a favorable regeneration of homogeneous and compact pulp-like tissues with abundantly distributed blood capillaries and to the deposition of regenerated dentin along the intracanal walls at 8 weeks post-operation. Thus, the application of DPSC/PRF tissue constructs might serve as a potential therapy in regenerative endodontics for pulp revitalization or revascularization.

Experimental Evaluation of the Effectiveness of Demineralized Bone Matrix and Collagenated Heterologous Bone Grafts Used Alone or in Combination with Platelet-Rich Fibrin on Bone Healing in Sinus Floor Augmentation.

PubMed

Peker, Elif; Karaca, Inci Rana; Yildirim, Benay

2016-01-01

The aim of this study was an experimental evaluation of the effectiveness of demineralized bone matrix (DBM) and collagenated heterologous bone graft (CHBG) used alone or in combination with platelet-rich fibrin on bone healing in sinus floor augmentation procedures. In this study, 36 New Zealand rabbits were used. The bilateral sinus elevation was performed, and 72 defects were obtained. The rabbit maxillary sinuses were divided into four groups according to the augmentation biomaterials obtained: demineralized bone matrix (Grafton DBM Putty, Osteotech; DBM group), DBM combined with platelet-rich fibrin (PRF; DBM + PRF group), collagenated heterologous bone graft (CHBG; Apatos Mix, OsteoBiol, Tecnoss; CHBG group), CHBG combined with PRF (CHBG + PRF group). All groups were sacrificed at 2, 4, and 8 weeks after surgery for histologic, histomorphometric, and immunohistochemical analyses. The inflammatory reaction was moderate to intense at the second week in all groups and declined from 2 to 8 weeks. New bone formation was started at the second week and increased from 2 to 8 weeks in all groups. There was no significant difference in bone formation between the experimental groups that used PRF mixed graft material and control groups that used only graft material. The percentage of new bone formation showed a significant difference in DBM groups and DBM + PRF groups compared with other groups. There were osteoclasts around all the bone graft materials used, but the percentage of residual graft particles was significantly higher in CHBG groups and CHBG + PRF groups at the eighth week. There is no beneficial effect of the application of PRF in combination with demineralized bone matrix or collagenated heterologous bone graft on bone formation in sinus floor augmentation. The results of this study showed that both collagenated heterologous bone graft and demineralized bone matrix have osteoconductive properties, but demineralized bone matrix showed more bone formation than collagenated heterologous bone graft.

Evaluation of the effects of platelet-rich fibrin on bone regeneration in diabetic rabbits.

PubMed

Durmuşlar, M Cenk; Ballı, Umut; Öngöz Dede, Figen; Bozkurt Doğan, Şeyma; Mısır, A Ferhat; Barış, Emre; Yılmaz, Zehra; Çelik, H Hamdi; Vatansever, Alper

2016-02-01

This study aimed to investigate the effect of platelet-rich fibrin on bone regeneration in critical size defects in the calvaria of diabetic rabbits. In total, 40 male New Zealand rabbits, were divided into two groups a non-diabetic control group (Group A) and a diabetic experimental group (Group B). Two bicortical circular defects 15 mm in diameter were created in the parietal bone of each animal. Each group was further divided into four groups: subgroup E, the defect was left empty; subgroup PRF, the defects were filled only with PRF; subgroup AB, the defects were filled with autogenous bone; subgroup AB + PRF, the defects were filled with autogenous bone combined with PRF. The animals sacrificed at 4 weeks and 8 weeks. Bone formation was assessed by micro-computed tomography (micro-CT) scanning, histological and histomorphometric analysis. The total percent of new bone was the lowest in group A-E (6.77 ± 0.21 at 4 weeks, 11.01 ± 0.37 at 8 weeks) and highest in group A-AB + PRF (21.66 ± 0.91 at 4 weeks, 37.46 ± 1.25 at 8 weeks; p < 0.05). The mean percent of new bone was greatest in group B-AB + PRF at 4 and 8 weeks (16.87 ± 0.92, 29.59 ± 1.09, respectively) and lowest in group B-E (5.83 ± 0.09 at 4 weeks, 7.36 ± 1.02 at 8 weeks). This study, despite its limitations, showed that PRF can be used safely and that PRF induced bone healing in diabetic rabbits. Copyright © 2015 European Association for Cranio-Maxillo-Facial Surgery. All rights reserved.

Development and validation of a score to predict postoperative respiratory failure in a multicentre European cohort: A prospective, observational study.

PubMed

Canet, Jaume; Sabaté, Sergi; Mazo, Valentín; Gallart, Lluís; de Abreu, Marcelo Gama; Belda, Javier; Langeron, Olivier; Hoeft, Andreas; Pelosi, Paolo

2015-07-01

Postoperative respiratory failure (PRF) is the most frequent respiratory complication following surgery. The objective of this study was to build a clinically useful predictive model for the development of PRF. A prospective observational study of a multicentre cohort. Sixty-three hospitals across Europe. Patients undergoing any surgical procedure under general or regional anaesthesia during 7-day recruitment periods. Development of PRF within 5 days of surgery. PRF was defined by a partial pressure of oxygen in arterial blood (PaO2) less than 8 kPa or new onset oxyhaemoglobin saturation measured by pulse oximetry (SpO2) less than 90% whilst breathing room air that required conventional oxygen therapy, noninvasive or invasive mechanical ventilation. PRF developed in 224 patients (4.2% of the 5384 patients studied). In-hospital mortality [95% confidence interval (95% CI)] was higher in patients who developed PRF [10.3% (6.3 to 14.3) vs. 0.4% (0.2 to 0.6)]. Regression modelling identified a predictive PRF score that includes seven independent risk factors: low preoperative SpO2; at least one preoperative respiratory symptom; preoperative chronic liver disease; history of congestive heart failure; open intrathoracic or upper abdominal surgery; surgical procedure lasting at least 2 h; and emergency surgery. The area under the receiver operating characteristic curve (c-statistic) was 0.82 (95% CI 0.79 to 0.85) and the Hosmer-Lemeshow goodness-of-fit statistic was 7.08 (P = 0.253). A risk score based on seven objective, easily assessed factors was able to predict which patients would develop PRF. The score could potentially facilitate preoperative risk assessment and management and provide a basis for testing interventions to improve outcomes.The study was registered at ClinicalTrials.gov (identifier NCT01346709).

Mutations in a Highly Conserved Motif of nsp1β Protein Attenuate the Innate Immune Suppression Function of Porcine Reproductive and Respiratory Syndrome Virus

PubMed Central

Li, Yanhua; Shyu, Duan-Liang; Shang, Pengcheng; Bai, Jianfa; Ouyang, Kang; Dhakal, Santosh; Hiremath, Jagadish; Binjawadagi, Basavaraj

2016-01-01

ABSTRACT Porcine reproductive and respiratory syndrome virus (PRRSV) nonstructural protein 1β (nsp1β) is a multifunctional viral protein, which is involved in suppressing the host innate immune response and activating a unique −2/−1 programmed ribosomal frameshifting (PRF) signal for the expression of frameshifting products. In this study, site-directed mutagenesis analysis showed that the R128A or R129A mutation introduced into a highly conserved motif (123GKYLQRRLQ131) reduced the ability of nsp1β to suppress interferon beta (IFN-β) activation and also impaired nsp1β's function as a PRF transactivator. Three recombinant viruses, vR128A, vR129A, and vRR129AA, carrying single or double mutations in the GKYLQRRLQ motif were characterized. In comparison to the wild-type (WT) virus, vR128A and vR129A showed slightly reduced growth abilities, while the vRR129AA mutant had a significantly reduced growth ability in infected cells. Consistent with the attenuated growth phenotype in vitro, pigs infected with nsp1β mutants had lower levels of viremia than did WT virus-infected pigs. Compared to the WT virus in infected cells, all three mutated viruses stimulated high levels of IFN-α expression and exhibited a reduced ability to suppress the mRNA expression of selected interferon-stimulated genes (ISGs). In pigs infected with nsp1β mutants, IFN-α production was increased in the lungs at early time points postinfection, which was correlated with increased innate NK cell function. Furthermore, the augmented innate response was consistent with the increased production of IFN-γ in pigs infected with mutated viruses. These data demonstrate that residues R128 and R129 are critical for nsp1β function and that modifying these key residues in the GKYLQRRLQ motif attenuates virus growth ability and improves the innate and adaptive immune responses in infected animals. IMPORTANCE PRRSV infection induces poor antiviral innate IFN and cytokine responses, which results in weak adaptive immunity. One of the strategies in next-generation vaccine construction is to manipulate viral proteins/genetic elements involved in antagonizing the host immune response. PRRSV nsp1β was identified to be a strong innate immune antagonist. In this study, two basic amino acids, R128 and R129, in a highly conserved GKYLQRRLQ motif were determined to be critical for nsp1β function. Mutations introduced into these two residues attenuated virus growth and improved the innate and adaptive immune responses of infected animals. Technologies developed in this study could be broadly applied to current commercial PRRSV modified live-virus (MLV) vaccines and other candidate vaccines. PMID:26792733

Identification of a novel plant amalgavirus (Amalgavirus, Amalgaviridae) genome sequence in Cistus incanus.

PubMed

Goh, C J; Park, D; Lee, J S; Sebastiani, F; Hahn, Y

2018-01-01

Amalgaviridae is a family of double-stranded, monosegmented RNA viruses that are associated with plants, fungi, microsporidians, and animals. A sequence contig derived from the transcriptome of a eudicot, Cistus incanus (the family Cistaceae; commonly known as hoary rockrose), was identified as the genome sequence of a novel plant RNA virus and named Cistus incanus RNA virus 1 (CiRV1). Sequence comparison and phylogenetic analysis indicated that CiRV1 is a novel species of the genus Amalgavirus in the family Amalgaviridae. The CiRV1 genome contig has two overlapping open reading frames (ORFs). ORF1 encodes a putative replication factory matrix-like protein, while ORF2 encodes a RNA-dependent RNA polymerase (RdRp) domain. An ORF1+2 fusion protein, which functions in viral RNA replication, is produced by a +1 programmed ribosomal frameshifting (PRF) mechanism. A +1 PRF motif UUU_CGU, which matches the conserved amalgavirus +1 PRF consensus sequence UUU_CGN, was found at the boundary of CiRV1 ORF1 and ORF2. Comparison of 25 amalgavirus ORF1+2 fusion proteins revealed that only three different positions within a 13-amino acid segment were recurrently used at the boundary, possibly being selected so as not to interfere with correct folding and function of the fusion protein. CiRV1 is the first virus found to be associated with the Cistus species and may be useful for studying amalgaviruses.

A Multiantigenic DNA Vaccine That Induces Broad Hepatitis C Virus-Specific T-Cell Responses in Mice.

PubMed

Gummow, Jason; Li, Yanrui; Yu, Wenbo; Garrod, Tamsin; Wijesundara, Danushka; Brennan, Amelia J; Mullick, Ranajoy; Voskoboinik, Ilia; Grubor-Bauk, Branka; Gowans, Eric J

2015-08-01

There are 3 to 4 million new hepatitis C virus (HCV) infections annually around the world, but no vaccine is available. Robust T-cell mediated responses are necessary for effective clearance of the virus, and DNA vaccines result in a cell-mediated bias. Adjuvants are often required for effective vaccination, but during natural lytic viral infections damage-associated molecular patterns (DAMPs) are released, which act as natural adjuvants. Hence, a vaccine that induces cell necrosis and releases DAMPs will result in cell-mediated immunity (CMI), similar to that resulting from natural lytic viral infection. We have generated a DNA vaccine with the ability to elicit strong CMI against the HCV nonstructural (NS) proteins (3, 4A, 4B, and 5B) by encoding a cytolytic protein, perforin (PRF), and the antigens on a single plasmid. We examined the efficacy of the vaccines in C57BL/6 mice, as determined by gamma interferon enzyme-linked immunosorbent spot assay, cell proliferation studies, and intracellular cytokine production. Initially, we showed that encoding the NS4A protein in a vaccine which encoded only NS3 reduced the immunogenicity of NS3, whereas including PRF increased NS3 immunogenicity. In contrast, the inclusion of NS4A increased the immunogenicity of the NS3, NS4B, andNS5B proteins, when encoded in a DNA vaccine that also encoded PRF. Finally, vaccines that also encoded PRF elicited similar levels of CMI against each protein after vaccination with DNA encoding NS3, NS4A, NS4B, and NS5B compared to mice vaccinated with DNA encoding only NS3 or NS4B/5B. Thus, we have developed a promising "multiantigen" vaccine that elicits robust CMI. Since their development, vaccines have reduced the global burden of disease. One strategy for vaccine development is to use commercially viable DNA technology, which has the potential to generate robust immune responses. Hepatitis C virus causes chronic liver infection and is a leading cause of liver cancer. To date, no vaccine is currently available, and treatment is costly and often results in side effects, limiting the number of patients who are treated. Despite recent advances in treatment, prevention remains the key to efficient control and elimination of this virus. Here, we describe a novel DNA vaccine against hepatitis C virus that is capable of inducing robust cell-mediated immune responses in mice and is a promising vaccine candidate for humans. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

A posterior approach to cervical nerve root block and pulsed radiofrequency treatment for cervical radicular pain: a retrospective study.

PubMed

Xiao, Lizu; Li, Jie; Li, Disen; Yan, Dong; Yang, Jun; Wang, Daniel; Cheng, Jianguo

2015-09-01

Catastrophic complications have been reported for selective cervical nerve root block (SCNRB) or pulsed radiofrequency (PRF) via an anterolateral transforaminal approach. A posterior approach to these procedures under computed tomography guidance has been reported. Here, we report the clinical outcomes of 42 patients with chronic cervical radicular pain (CCRP) treated with a combination of SCNRB and PRF through a posterior approach under fluoroscopy guidance. We retrospectively reviewed the clinical outcomes of 42 consecutive patients with CCRP who received a combination of SCNRB and PRF through a posterior approach under fluoroscopy guidance. The thresholds of electrical stimulation and imaging of the nerve roots after contrast injection were used to evaluate the accuracy of needle placement. The numeric rating scale was used to measure the pain and numbness levels as primary clinical outcomes, which were evaluate in scheduled follow-up visits of up to 3 months. A total of 53 procedures were performed on 42 patients at the levels of C5-C8. All patients reported concordant paresthesia in response to electrical stimulation. The average sensory and motor thresholds of stimulation were 0.28 ± 0.14 and 0.36 ± 0.14 V, respectively. Injection of nonionic contrast resulted in excellent spread along the target nerve root in large majority of the procedures. The numeric rating scale scores for both pain and numbness improved significantly at 1 day, 1 week, and 1 and 3 months after the treatment. No serious adverse effects were observed in any of the patients. The posterior approach to combined SCNRB and PRF under fluoroscopy guidance appears to be safe and efficacious in the management of CCRP. Copyright © 2015 Elsevier Inc. All rights reserved.

Long-term cytokine and growth factor release from equine platelet-rich fibrin clots obtained with two different centrifugation protocols.

PubMed

Jiménez-Aristizabal, Román F; López, Catalina; Álvarez, María E; Giraldo, Carlos; Prades, Marta; Carmona, Jorge U

2017-09-01

To compare the temporal release (over three weeks) of tumor necrosis factor alpha (TNF-α), interleukin 4 (IL-4), IL-1 receptor antagonist (IL-1ra), platelet-derived growth factor BB (PDGF-BB) and transforming growth factor beta-1 (TGF-β 1 ) from two platelet-rich fibrin (PRF) preparations from equine blood obtained at either 240g/8min or 416g/10min. Whole blood from 10 horses was used to obtain PRF clots by two different centrifugation protocols. After 1h of rest, PRF clots were deposited in wells with culture medium, which was changed at 6h, 24h and then every 48h to 21days. Cytokines and GFs were measured by ELISA at 1h (serum supernatants from PRF clots) and all time points of culture medium change. A negative control (plasma) and a positive control (blood lysate) were also included. There were no relevant differences between the two protocols for the temporal release of proteins. However, a significant (p=0.01) effect of time was noted. All cytokines were detected after 6h of PRF clot culture until day 21. GF were detected at 1h until day 21. The concentrations for these proteins diminished gradually over time. A highly significant (p=0.01) correlation was noticed between all the proteins evaluated. Leukocytes enmeshed in PRF clots were able to produce cytokines, TGF-β 1 and PDGF-BB. These findings demonstrate a paramount role of leukocytes in wound healing induced or modified by PRF clots in mammals. Copyright © 2017 Elsevier Ltd. All rights reserved.

Differential expression of Listeria monocytogenes virulence genes in mammalian host cells.

PubMed

Bubert, A; Sokolovic, Z; Chun, S K; Papatheodorou, L; Simm, A; Goebel, W

1999-03-01

We have used RT-PCR and GFP-mediated fluorescence to analyse the regulation of PrfA-dependent virulence genes of Listeria monocytogenes during proliferation in mammalian host cells. Our data show that most of the PrfA-regulated virulence genes are more efficiently expressed, as measured by transcript levels, when L. monocytogenes is grown in macrophages and macrophage-like cells rather than in epithelial cells, hepatocytes or endothelial cells. The promoters for hly and plcA are predominantly activated within the phagosomal compartment, while those for actA and inlC are predominantly activated in the host cell cytosol. Expression of actA and plcB precedes that of inlC after infection of epithelial cells and macrophages. Little transcription of inlA or inlB is observed in epithelial cells and there is only slightly more in macrophages. In both cell types the level of transcription of the inlAB operon is lower than is seen under extracellular growth conditions in rich media, which is compatible with the assumption that InlA and InlB are not required during intracellular growth of the bacteria. Activation of the PrfA-independent iap promoter is also low during intracellular growth, although the gene product (p60) is required for cell viability. The levels of the PrfA-dependent virulence gene transcripts do not correlate with the amount of prfA transcript present, which is low under all intracellular conditions analysed, suggesting that the prfA transcript is either highly unstable in bacteria that are growing intracellularly, or that the small amount of PrfA produced is highly activated by additional component(s).

Effect of Pulsed Radiofrequency Treatment on the Thoracic Medial Branch for Managing Chronic Thoracic Facet Joint Pain Refractory to Medial Branch Block with Local Anesthetics.

PubMed

Chang, Min Cheol

2018-03-01

To evaluate the effect of pulsed radiofrequency (PRF) stimulation of the thoracic medial branch of the dorsal ramus in patients with chronic thoracic facet joint (TFJ) pain who were refractory to medial branch block (MBB). This was a prospective, observational study. The author retrospectively reviewed data from 72 patients who had received therapeutic MBB with 0.5 mL of 2% lidocaine mixed with 0.5 mL of 0.25% bupivacaine to treat TFJ-origin upper or midback pain. Of these patients, 20 were included to evaluate the effects of PRF on the thoracic medical branch to manage TFJ pain refractory to therapeutic MBB. PRF stimulation was administered at 5 Hz and a 5-millisecond pulsed width for 360 seconds at 45 V. The pain-reducing effect of the PRF procedure was evaluated via the numeric rating scale (NRS) at 1, 2, and 3 months after treatment. Successful pain relief was defined as ≥50% reduction in the NRS score compared with the score before treatment. The NRS scores changed significantly over time (pretreatment, 6.0 ± 1.0; 1 month, 3.3 ± 2.2; 2 months, 3.9 ± 2.1; and 3 months, 4.0 ± 2.2). At 1, 2, and 3 months after the PRF procedure, the NRS scores were significantly reduced compared with the scores before the treatment. Eleven (55%) of 20 patients reported successful pain relief at 3 months after PRF. The author suggests that PRF on the thoracic medial branch is an effective and safe interventional technique for the control of chronic TFJ pain. Copyright © 2017 Elsevier Inc. All rights reserved.

Perifosine enhances bevacizumab-induced apoptosis and therapeutic efficacy by targeting PI3K/AKT pathway in a glioblastoma heterotopic model.

PubMed

Ramezani, Sara; Vousooghi, Nasim; Ramezani Kapourchali, Fatemeh; Joghataei, Mohammad Taghi

2017-08-01

Bevacizumab (BVZ) as an antiangiogenesis therapy leads to a transient therapeutic efficacy in high-grade glioma. However, the proapoptotic potential of BVZ has not been well elucidated, yet. There is also a tumor resistance to BVZ that is linked to post-treatment metalloproteinases and AKT activities. Herein, the association between therapeutic efficacy and putative proapoptotic activity of low-dose BVZ either alone or in combination with a specific inhibitor of AKT called perifosine (PRF), in a glioma model was investigated. BALB/c mice bearing C6 glioma tumor were treated with BVZ and PRF either alone or combined for 13 days (n = 11/group). At the end of treatments, apoptosis, proliferation and vascular density, in the xenografts (3/group) were detected by TUNEL staining, Ki67 and CD31 markers, respectively. Relative levels of cleaved-caspase3, phospho-AKT (Ser473) and matrix metalloproteinase2 (MMP2) were measured using western blotting. PRF and BVZ separately slowed down tumor growth along with the cell apoptosis induction associated with a profound increase in caspase3 activity through an AKT inhibition-related pathway for PRF but not BVZ. Unlike PRF, BVZ significantly increased the intratumor MMP2 and phospho-AKT (Ser473) levels coupled with the slight antiproliferative and significant antivascular effects. Co-administration of PRF and BVZ versus monotherapies potentiated the proapoptotic effects and reversed the BVZ-induced upregulation of phospho-AKT (Ser473) and MMP2 levels in C6 xenografts, leading to the optimal antiproliferative activity and tumor growth regression and longer survival. In conclusion, BVZ plus PRF renders a paramount proapoptotic effect, leading to a major therapeutic efficacy and might be a new substitute for GBM therapy in the clinic.

Effects of Pulsed Versus Conventional Versus Combined Radiofrequency for the Treatment of Trigeminal Neuralgia: A Prospective Study.

PubMed

Elawamy, Abdelraheem; Abdalla, Esam Eldein Mohamed; Shehata, Ghaydaa A

2017-09-01

During radiofrequency bursts of energy are applied to nervous tissue. The clinical advantages of this treatment remain unclear. We compared the effectiveness and pain relief for idiopathic trigeminal neuralgia (TN) after continuous radiofrequency (CRF), pulsed radiofrequency (PRF), and combined continuous and pulsed radiofrequency (CCPRF) treatment of the Gasserian ganglion (GG). We conducted a randomized prospective study. Forty-three patients were included. Eleven patients were treated with PRF at 42°C for 10 minutes (PRF group), 12 patients received CRF for 270 seconds at 75 °C (CRF group), and 20 patients received PRF for 10 minutes at 42°C followed by CRF for at 60°C for 270 seconds (CCPRF group). Assuit University Hospital, Pain and Neurology outpatient clinics. Patients were assessed for pain, satisfaction, and consumption of analgesics at baseline and 7 days, one month, 6 months, 12 months, and 24 months after the procedure. The incidence of complications, anesthesia dolorosa, weakness of muscles of mastication, numbness, and technical complications, was evaluated after the procedure. Excellent pain relief was achieved after 6, 12, and 24 months, respectively in 95%, 85%, and 70% of patients with CCPRF; 75%, 75%, and reduced to 50% among patients with CRF; and 82%, reduced to 9.1%, and 0% of patients with PRF. No complications were recorded in 75% of patients in the CCPRF and PRF groups. There was one case of anesthesia dolorosa, 4 cases of masseter muscle weakness, and 5 cases of severe numbness recorded in the CRF group. There was a small number of patients in each group. The best results were observed in the CCPRF group, followed by the CRF group, and then the PRF group.Key words: Pulsed, continuous, radiofrequency, trigeminal neuralgia, Gasserian ganglion.

Platelet-Poor Plasma as a Supplement for Fibroblasts Cultured in Platelet-Rich Fibrin

PubMed Central

Karam, Sarah Arangurem; Noronha, Thaís Gioda; Sartori, Letícia Regina Morello; San Martin, Alissa Schmidt; Demarco, Flávio Fernando; Conde, Marcus Cristian Muniz

2017-01-01

The aim of this study was to evaluate the proliferation and adhesion of mesenchymal cells (3T3/NIH) in Dulbecco’s Modified Eagle Medium(DMEM) supplemented with Platelet-Poor Plasma (PPP) in aPlatelet-Rich Fibrin (PRF) scaffold. Human blood was obtained and processed in a centrifuge considering the equation G=1.12xRx(RPM/1000)2 to obtain PRF and PPP.Cell adhesion and maintenance analyses were performed by MTTassays in a 96 well plate withsupplemented DMEM: PPP (90:10) for 24 hours. Besides, the PRF was deposited in a 48 well plate and 10x104 cells were seeded above each PRF (n=3) with 800µl of DMEM: PPP (90:10) and cultured for 7 days. Histological analysis and the immunohistochemical staining for Vimentin were performed. Results were analyzed by one-way ANOVA in Stata12®. A significant decrease (p<0.05) of cells adhesion in relationship to FBSwas observed. However, a similar ability of cell-maintenance for PPP 10% was observed (P>0.05). Fibroblasts culture for 7 days in PRF supplemented with PPP 10% was possible, showing positive staining for Vimentin. Therefore, PPP cell supplementation decreased the initial adhesion of cells but was able to maintain the proliferation of adhered cells and able to support their viability in PRF.It seems that this method has many clinical advantagessince it provides an autologous and natural scaffold with their respective supplement for cell culture by only one process, without using xenogeneic compounds. This could improve the potential of clinical translational therapies based on the use of PRF cultured cells, promoting the regenerative potential for future use in medicine and dentistry. PMID:28827850

Sustained Release of Transforming Growth Factor-β1 from Platelet-Rich Chondroitin Sulfate Glycosaminoglycan Gels

PubMed Central

Birdwhistell, Kate E.; Karumbaiah, Lohitash; Franklin, Samuel P.

2018-01-01

Activated platelet-rich plasma (PRP), also referred to as platelet-rich fibrin (PRF), has been used to augment numerous techniques of cartilage repair in the knee but does not always result in superior quality of repair tissue. One possible reason that PRF does not consistently result in excellent cartilage regeneration is the transiency of growth factor provision with PRF. The objective of this study was to compare the release of transforming growth factor (TGF)-β1 from PRF and from PRP combined with a novel chondroitin sulfate glycosaminoglycan (CS-GAG) gel. PRP was prepared from nine healthy dogs and split into two aliquots: one activated with bovine thrombin and calcium chloride (CaCl2) to form PRF and the other aliquot was used to rehydrate a lyophilized CS-GAG gel. Both PRF and the CS-GAG gels were incubated in media for 13 days and media were collected, stored, and replaced every 48 hours and the concentration of TGF-β1 quantified in the media using an enzyme-linked immunosorbent assay. Concentrations of TGF-β1 in the media were up to three times greater with the CS-GAG gels and were significantly (p < 0.05) greater than with PRF on days 3, 5, 7, 9, and 13. Furthermore, TGF-β1 elution was still substantial at day 13 with the use of the CS-GAG gels. Additional in vitro work is warranted to characterize TGF-β1 elution from this CS-GAG gel with human PRP and to determine whether the use of these CS-GAG gels can augment cartilage repair in vivo. PMID:28645130

Identification of a Peptide-Pheromone that Enhances Listeria monocytogenes Escape from Host Cell Vacuoles

PubMed Central

Xayarath, Bobbi; Alonzo, Francis; Freitag, Nancy E.

2015-01-01

Listeria monocytogenes is a Gram-positive facultative intracellular bacterial pathogen that invades mammalian cells and escapes from membrane-bound vacuoles to replicate within the host cell cytosol. Gene products required for intracellular bacterial growth and bacterial spread to adjacent cells are regulated by a transcriptional activator known as PrfA. PrfA becomes activated following L. monocytogenes entry into host cells, however the signal that stimulates PrfA activation has not yet been defined. Here we provide evidence for L. monocytogenes secretion of a small peptide pheromone, pPplA, which enhances the escape of L. monocytogenes from host cell vacuoles and may facilitate PrfA activation. The pPplA pheromone is generated via the proteolytic processing of the PplA lipoprotein secretion signal peptide. While the PplA lipoprotein is dispensable for pathogenesis, bacteria lacking the pPplA pheromone are significantly attenuated for virulence in mice and have a reduced efficiency of bacterial escape from the vacuoles of nonprofessional phagocytic cells. Mutational activation of PrfA restores virulence and eliminates the need for pPplA-dependent signaling. Experimental evidence suggests that the pPplA peptide may help signal to L. monocytogenes its presence within the confines of the host cell vacuole, stimulating the expression of gene products that contribute to vacuole escape and facilitating PrfA activation to promote bacterial growth within the cytosol. PMID:25822753

Fibrin glue mixed with platelet-rich fibrin as a scaffold seeded with dental bud cells for tooth regeneration.

PubMed

Yang, Kai-Chiang; Wang, Chun-Hao; Chang, Hao-Hueng; Chan, Wing P; Chi, Chau-Hwa; Kuo, Tzong-Fu

2012-11-01

Odontogenesis is a complex process with a series of epithelial-mesenchymal interactions and odontogenic molecular cascades. In tissue engineering of teeth from stem cells, platelet-rich fibrin (PRF), which is rich in growth factors and cytokines, may improve regeneration. Accordingly, PRF was added into fibrin glue to enrich the microenvironment with growth factors. Unerupted second molar tooth buds were harvested from miniature swine and cultured in vitro for 3 weeks to obtain dental bud cells (DBCs). Whole blood was collected for the preparation of PRF and fibrin glue before surgery. DBCs were suspended in fibrin glue and then enclosed with PRF, and the DBC-fibrin glue-PRF composite was autografted back into the original alveolar sockets. Radiographic and histological examinations were used to identify the regenerated tooth structure 36 weeks after implantation. Immunohistochemical staining was used to detect proteins specific to tooth regeneration. One pig developed a complete tooth with crown, root, pulp, enamel, dentin, odontoblast, cementum, blood vessels, and periodontal ligaments in indiscriminate shape. Another animal had an unerupted tooth that expressed cytokeratin 14, dentin matrix protein-1, vascular endothelial growth factor, and osteopontin. This study demonstrated, using autogenic cell transplantation in a porcine model, that DBCs seeded into fibrin glue-PRF could regenerate a complete tooth. Copyright © 2011 John Wiley & Sons, Ltd.

Effect of intradiscal pulsed radiofrequency on refractory chronic discogenic neck pain: A case report.

PubMed

Kwak, So Young; Chang, Min Cheol

2018-04-01

Despite medication, exercise, and medical intervention, many patients complain of persistent discogenic neck pain. To manage discogenic neck pain, we performed intradiscal pulsed radiofrequency (PRF) stimulation in a patient with chronic discogenic neck pain refractory to oral medication and epidural steroid injection. A 26-year-old man presented with a numeric rating scale (NRS) score of 7 for chronic neck pain. His pain was worse when the neck was held in one position for a prolonged period. There was no pain in the upper extremities. Discography was positive at C4-5. Based on the pain characteristics, and the result of discography, we diagnosed him as having discogenic neck pain originating from C4-5. Intradiscal PRF on the C4-5 intervertebral disc was performed under C-arm fluoroscopy. The PRF treatment was administered at 2 Hz and a 20-ms pulsed width for 20 minutes at 60 V with the constraint that the electrode tip temperature should not exceed 42°C. At the 2-week, and 1-month follow-up visits, the patient's pain was completely relieved. At 2, and 3 months after intradiscal PRF, the pain was scored as NRS 2. No adverse effects of intradiscal PRF stimulation were observed. Application of intradiscal PRF appears to be an effective and safe technique for treating chronic discogenic neck pain.

GrayQb TM Single-Faced Version 2 (SF2) Hanford Plutonium Reclamation Facility (PRF) deployment report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Plummer, J. R.; Immel, D. M.; Serrato, M. G.

2015-11-18

The Savannah River National Laboratory (SRNL) in partnership with CH2M Plateau Remediation Company (CHPRC) deployed the GrayQb TM SF2 radiation imaging device at the Hanford Plutonium Reclamation Facility (PRF) to assist in the radiological characterization of the canyon. The deployment goal was to locate radiological contamination hot spots in the PRF canyon, where pencil tanks were removed and decontamination/debris removal operations are on-going, to support the CHPRC facility decontamination and decommissioning (D&D) effort. The PRF canyon D&D effort supports completion of the CHPRC Plutonium Finishing Plant Decommissioning Project. The GrayQb TM SF2 (Single Faced Version 2) is a non-destructive examinationmore » device developed by SRNL to generate radiation contour maps showing source locations and relative radiological levels present in the area under examination. The Hanford PRF GrayQbTM Deployment was sponsored by CH2M Plateau Remediation Company (CHPRC) through the DOE Richland Operations Office, Inter-Entity Work Order (IEWO), DOE-RL IEWO- M0SR900210.« less

Intermolecular hydrogen bonds in hetero-complexes of biologically active aromatic molecules probed by the methods of vibrational spectroscopy

NASA Astrophysics Data System (ADS)

Semenov, M. A.; Blyzniuk, Iu. N.; Bolbukh, T. V.; Shestopalova, A. V.; Evstigneev, M. P.; Maleev, V. Ya.

2012-09-01

By the methods of vibrational spectroscopy (Infrared and Raman) the investigation of the hetero-association of biologically active aromatic compounds: flavin-mononucleotide (FMN), ethidium bromide (EB) and proflavine (PRF) was performed in aqueous solutions. It was shown that between the functional groups (Cdbnd O and NH2) the intermolecular hydrogen bonds are formed in the hetero-complexes FMN-EB and FMN-PRF, additionally stabilizing these structures. An estimation of the enthalpy of Н-bonding obtained from experimental shifts of carbonyl vibrational frequencies has shown that the H-bonds do not dominate in the magnitude of experimentally measured total enthalpy of the hetero-association reactions. The main stabilization is likely due to intermolecular interactions of the molecules in these complexes and their interaction with water environment.

[The significance of pedigree genetic screening and rapid immunological parameters in the diagnosis of primary hemophagocytic lymphohistiocytosis].

PubMed

Zhang, J; Wang, Y N; Wang, J S; Wu, L; Wei, N; Fu, L; Gao, Z; Chen, J H; Pei, R J; Wang, Z

2016-07-01

To investigate the significance of pedigree genetic screening and rapid immunological parameters in the diagnosis of primary hemophagocytic lymphohistiocytosis (HLH). Four cases of primary HLH patients with PRF1, UNC13D and SH2D1A gene mutations were conducted pedigree investigation, including family genetic screening and detections of immunological parameters (NK cell activity, CD107a degranulation and expression of HLH related defective protein), to evaluate the significance of these different indicators in the diagnosis of primary HLH and explore their correlations. The DNA mutations of the four families included missense mutation c.T172C (p.S58P) and non- frameshift deletions c.1083_1094del (p.361_365del), missense mutation c.C1349T (p.T450M) and frameshift mutation c.1090_1091delCT (p.T364fsX93) in PRF1 gene, missense mutation c.G2588A (p.G863D) in UNC13D gene and hemizygous mutation c.32T>G (p.I11S) in SH2D1A gene. The patients and their family members presented decreased NK cell activities. Individuals who carried mutations of PRF1 gene and SH2D1A gene showed low expression of perforin (PRF1) and signaling lymphocytic activation molecule associated protein (SAP). And the patient with UNC13D gene mutation and his family member with identical mutation showed significant reducing cytotoxic degranulation function (expression of CD107a). Pedigree genetic screening and rapid detection of immunological parameters might play an important role in the diagnosis of primary HLH, and both of them had good consistency. As an efficient detection means, the rapid immunological detection indicators would provide reliable basis for the early diagnosis of the primary HLH.

Demonstration and Validation of a High-Performance Floor-Sealant System to Reduce Concrete Degradation

DTIC Science & Technology

2015-05-01

1 Recycled Antifreeze 01-197-7692 MIL-PRF-10924H GAA Grease 01-102-9455 MIL-PRF-46176B Brake Fluid 00-252-6383 MIL-PRF-5606H Hydraulic Fluid H515...contaminated clothing , clean thoroughly before reuse. Inhalation: Move to fresh air. If not breathing, give rescue breathing. I f breathing is...material to absorb the spill, use plastic shovel to pick up absorbent for disposal Spills and Leaks: Dispose in accordance to local, state or federal

Comparison between ultrasound-guided interfascial pulsed radiofrequency and ultrasound-guided interfascial block with local anesthetic in myofascial pain syndrome of trapezius muscle

PubMed Central

Cho, Ik Tae; Cho, Yun Woo; Kwak, Sang Gyu; Chang, Min Cheol

2017-01-01

Abstract Myofascial pain syndrome (MPS) of the trapezius muscle (TM) is a frequently occurring musculoskeletal disorder. However, the treatment of MPS of the TM remains a challenge. We investigated the effects of ultrasound (US)-guided pulsed radiofrequency (PRF) stimulation on the interfascial area of the TM. In addition, we compared its effect with that of interfascial block (IFB) with 10 mL of 0.6% lidocaine on the interfascial area of the TM. Thirty-six patients with MPS of the TM were included and randomly assigned into 2 groups. Eighteen patients underwent PRF stimulation on the interfascial area of the TM (PRF group) and 18 patients underwent IFB with lidocaine on the same area (IFB group). Pain intensity was evaluated using a numerical rating scale (NRS) at pretreatment, 2, 4, and 8 weeks after treatment. At pretreatment and 8 weeks after treatment, quality of life was assessed using the Short Form-36 Health Survey (SF-36), which includes the physical component score (PCS) and the mental component score (MCS). One patient in the PRF group was lost to follow-up. Patients in both groups showed a significant decrease in NRS scores at 2, 4, and 8 weeks after treatments and a significant increase in PCS and MCS of the SF-36 at 8 weeks after treatments. Two weeks after each treatment, the decrements of NRS scores were not significantly different between the 2 groups. However, 4 and 8 weeks after the procedures, we found that the NRS score was significantly lower in the PRF group than in the IFB group. At 8 weeks after the treatments, PCS and MCS of the SF-36 in the PRF group were significantly higher than those in the IFB group. For the management of MPS of the TM, US-guided interfascial PRF had a better long-term effect on reducing the pain and the quality of life compared to US-guided IFB. Therefore, we think US-guided PRF stimulation on the interfascial area of the TM can be a beneficial alternative to manage the pain following MPS of the TM. PMID:28151904

Comparison between ultrasound-guided interfascial pulsed radiofrequency and ultrasound-guided interfascial block with local anesthetic in myofascial pain syndrome of trapezius muscle.

PubMed

Cho, Ik Tae; Cho, Yun Woo; Kwak, Sang Gyu; Chang, Min Cheol

2017-02-01

Myofascial pain syndrome (MPS) of the trapezius muscle (TM) is a frequently occurring musculoskeletal disorder. However, the treatment of MPS of the TM remains a challenge. We investigated the effects of ultrasound (US)-guided pulsed radiofrequency (PRF) stimulation on the interfascial area of the TM. In addition, we compared its effect with that of interfascial block (IFB) with 10 mL of 0.6% lidocaine on the interfascial area of the TM. Thirty-six patients with MPS of the TM were included and randomly assigned into 2 groups. Eighteen patients underwent PRF stimulation on the interfascial area of the TM (PRF group) and 18 patients underwent IFB with lidocaine on the same area (IFB group). Pain intensity was evaluated using a numerical rating scale (NRS) at pretreatment, 2, 4, and 8 weeks after treatment. At pretreatment and 8 weeks after treatment, quality of life was assessed using the Short Form-36 Health Survey (SF-36), which includes the physical component score (PCS) and the mental component score (MCS). One patient in the PRF group was lost to follow-up. Patients in both groups showed a significant decrease in NRS scores at 2, 4, and 8 weeks after treatments and a significant increase in PCS and MCS of the SF-36 at 8 weeks after treatments. Two weeks after each treatment, the decrements of NRS scores were not significantly different between the 2 groups. However, 4 and 8 weeks after the procedures, we found that the NRS score was significantly lower in the PRF group than in the IFB group. At 8 weeks after the treatments, PCS and MCS of the SF-36 in the PRF group were significantly higher than those in the IFB group. For the management of MPS of the TM, US-guided interfascial PRF had a better long-term effect on reducing the pain and the quality of life compared to US-guided IFB. Therefore, we think US-guided PRF stimulation on the interfascial area of the TM can be a beneficial alternative to manage the pain following MPS of the TM.

Identification of cholinergic and non-cholinergic neurons in the pons expressing phosphorylated cyclic adenosine monophosphate response element-binding protein as a function of rapid eye movement sleep.

PubMed

Datta, S; Siwek, D F; Stack, E C

2009-09-29

Recent studies have shown that in the pedunculopontine tegmental nucleus (PPT), increased neuronal activity and kainate receptor-mediated activation of intracellular protein kinase A (PKA) are important physiological and molecular steps for the generation of rapid eye movement (REM) sleep. In the present study performed on rats, phosphorylated cyclic AMP response element-binding protein (pCREB) immunostaining was used as a marker for increased intracellular PKA activation and as a reflection of increased neuronal activity. To identify whether activated cells were either cholinergic or noncholinergic, the PPT and laterodorsal tegmental nucleus (LDT) cells were immunostained for choline acetyltransferase (ChAT) in combination with pCREB or c-Fos. The results demonstrated that during high rapid eye movement sleep (HR, approximately 27%), significantly higher numbers of cells expressed pCREB and c-Fos in the PPT, of which 95% of pCREB-expressing cells were ChAT-positive. With HR, the numbers of pCREB-positive cells were also significantly higher in the medial pontine reticular formation (mPRF), pontine reticular nucleus oral (PnO), and dorsal subcoeruleus nucleus (SubCD) but very few in the locus coeruleus (LC) and dorsal raphe nucleus (DRN). Conversely, with low rapid eye movement sleep (LR, approximately 2%), the numbers of pCREB expressing cells were very few in the PPT, mPRF, PnO, and SubCD but significantly higher in the LC and DRN. The results of regression analyses revealed significant positive relationships between the total percentages of REM sleep and numbers of ChAT+/pCREB+ (Rsqr=0.98) cells in the PPT and pCREB+ cells in the mPRF (Rsqr=0.88), PnO (Rsqr=0.87), and SubCD (Rsqr=0.84); whereas significantly negative relationships were associated with the pCREB+ cells in the LC (Rsqr=0.70) and DRN (Rsqr=0.60). These results provide evidence supporting the hypothesis that during REM sleep, the PPT cholinergic neurons are active, whereas the LC and DRN neurons are inactive. More importantly, the regression analysis indicated that pCREB activation in approximately 98% of PPT cholinergic neurons, was caused by REM sleep. Moreover the results indicate that during REM sleep, PPT intracellular PKA activation and a transcriptional cascade involving pCREB occur exclusively in the cholinergic neurons.

Novel use of platelet-rich fibrin matrix and MTA as an apical barrier in the management of a failed revascularization case.

PubMed

Yadav, Pankaj; Pruthi, Preeti Jain; Naval, Ruchika Roongta; Talwar, Sangeeta; Verma, Mahesh

2015-08-01

We report management of a failed revascularization/revitalization case, which could be due to inadequate removal of biofilm and bacteria in dentinal tubules. The use of an apical matrix barrier in form of a platelet-rich fibrin (PRF) membrane for stabilization of MTA in root end apexification procedure is described. The canal was cleansed of old MTA present in the cervical third using H files, irrigated using saline and finally irrigated with 2.5% NaOCl and saline. To obtain canal disinfection, calcium hydroxide paste was temporized in the canal. In subsequent appointments, PRF was placed at the root tip followed by 5-mm apical plug with mineral trioxide aggregate. One week later, the root canal was obturated with thermoplasticized gutta-percha. A 6-month and a 2-year follow ups showed reduction of periapical radiolucency and adequately functional tooth. One-visit apexification techniques provide an alternative treatment for failed revascularization cases. Follow up confirmed complete healing periradicularly. Apexification in one step using an apical barrier of PRF and a plug of MTA can be considered a predictable treatment and may be an alternative to long-term revascularization failures. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Nanofat-derived stem cells with platelet-rich fibrin improve facial contour remodeling and skin rejuvenation after autologous structural fat transplantation

PubMed Central

Liang, Zhi-Jie; Chen, Hai; Zhu, Mao-Guang; Xu, Fang-Tian; He, Ning; Wei, Xiao-Juan; Li, Hong-Mian

2017-01-01

Traditional autologous fat transplantation is a common surgical procedure for treating facial soft tissue depression and skin aging. However, the transplanted fat is easily absorbed, reducing the long-term efficacy of the procedure. Here, we examined the efficacy of nanofat-assisted autologous fat structural transplantation. Nanofat-derived stem cells (NFSCs) were isolated, mechanically emulsified, cultured, and characterized. Platelet-rich fibrin (PRF) enhanced proliferation and adipogenic differentiation of NFSCs in vitro. We then compared 62 test group patients with soft tissue depression or signs of aging who underwent combined nanofat, PRF, and autologous fat structural transplantation to control patients (77 cases) who underwent traditional autologous fat transplantation. Facial soft tissue depression symptoms and skin texture were improved to a greater extent after nanofat transplants than after traditional transplants, and the nanofat group had an overall satisfaction rate above 90%. These data suggest that NFSCs function similarly to mesenchymal stem cells and share many of the biological characteristics of traditional fat stem cell cultures. Transplants that combine newly-isolated nanofat, which has a rich stromal vascular fraction (SVF), with PRF and autologous structural fat granules may therefore be a safe, highly-effective, and long-lasting method for remodeling facial contours and rejuvenating the skin. PMID:28978136

Polyphenol-rich food general and on pregnancy effects: a review.

PubMed

Hahn, Marla; Baierle, Marília; Charão, Mariele F; Bubols, Guilherme B; Gravina, Fernanda S; Zielinsky, Paulo; Arbo, Marcelo D; Cristina Garcia, Solange

2017-07-01

This review aimed to investigate possible protective or deleterious effects of polyphenol-rich foods (PRF) on chronic diseases, e.g. cardiovascular, and in pregnant women, along with their antioxidant and anti-inflammatory action. A great variety of foods and beverages, such as herbal teas, grape and orange derivatives, dark chocolate, and many others contain high concentrations of flavonoids and are freely consumed by the general population. In humans, PRF consumption reduces lipid peroxidation, and several studies have shown a positive correlation between an increased consumption of PRF and a decrease in the incidence of cardiovascular disease. On the other hand, current studies have suggested that maternal ingestion of PRF, especially during the third trimester of pregnancy, could be associated to fetal ductal constriction (DC). Fetuses exposed to this type of diet show higher ductal velocities and lower pulsatility indexes, as well as larger right ventricles than those exposed to minimal amounts of these substances. The underlying mechanism involved in these conditions has not been entirely elucidated, but it seems to be a result of the antioxidant and anti-inflammatory effects of polyphenols by some pathway. Furthermore, taking into account the deleterious effect in late-pregnancy against the numerous positive effects associated to polyphenols, this dual behavior deserves attention particularly to control the dietary ingestion of PRF during gestation. In this line, same PRF, natural constituents of human diet, may represent risk to fetal in late pregnancy compared to the use of nonsteroidal anti-inflammatory drugs.

Platelet Counts in Insoluble Platelet-Rich Fibrin Clots: A Direct Method for Accurate Determination.

PubMed

Kitamura, Yutaka; Watanabe, Taisuke; Nakamura, Masayuki; Isobe, Kazushige; Kawabata, Hideo; Uematsu, Kohya; Okuda, Kazuhiro; Nakata, Koh; Tanaka, Takaaki; Kawase, Tomoyuki

2018-01-01

Platelet-rich fibrin (PRF) clots have been used in regenerative dentistry most often, with the assumption that growth factor levels are concentrated in proportion to the platelet concentration. Platelet counts in PRF are generally determined indirectly by platelet counting in other liquid fractions. This study shows a method for direct estimation of platelet counts in PRF. To validate this method by determination of the recovery rate, whole-blood samples were obtained with an anticoagulant from healthy donors, and platelet-rich plasma (PRP) fractions were clotted with CaCl 2 by centrifugation and digested with tissue-plasminogen activator. Platelet counts were estimated before clotting and after digestion using an automatic hemocytometer. The method was then tested on PRF clots. The quality of platelets was examined by scanning electron microscopy and flow cytometry. In PRP-derived fibrin matrices, the recovery rate of platelets and white blood cells was 91.6 and 74.6%, respectively, after 24 h of digestion. In PRF clots associated with small and large red thrombi, platelet counts were 92.6 and 67.2% of the respective total platelet counts. These findings suggest that our direct method is sufficient for estimating the number of platelets trapped in an insoluble fibrin matrix and for determining that platelets are distributed in PRF clots and red thrombi roughly in proportion to their individual volumes. Therefore, we propose this direct digestion method for more accurate estimation of platelet counts in most types of platelet-enriched fibrin matrix.

Platelet Counts in Insoluble Platelet-Rich Fibrin Clots: A Direct Method for Accurate Determination

PubMed Central

Kitamura, Yutaka; Watanabe, Taisuke; Nakamura, Masayuki; Isobe, Kazushige; Kawabata, Hideo; Uematsu, Kohya; Okuda, Kazuhiro; Nakata, Koh; Tanaka, Takaaki; Kawase, Tomoyuki

2018-01-01

Platelet-rich fibrin (PRF) clots have been used in regenerative dentistry most often, with the assumption that growth factor levels are concentrated in proportion to the platelet concentration. Platelet counts in PRF are generally determined indirectly by platelet counting in other liquid fractions. This study shows a method for direct estimation of platelet counts in PRF. To validate this method by determination of the recovery rate, whole-blood samples were obtained with an anticoagulant from healthy donors, and platelet-rich plasma (PRP) fractions were clotted with CaCl2 by centrifugation and digested with tissue-plasminogen activator. Platelet counts were estimated before clotting and after digestion using an automatic hemocytometer. The method was then tested on PRF clots. The quality of platelets was examined by scanning electron microscopy and flow cytometry. In PRP-derived fibrin matrices, the recovery rate of platelets and white blood cells was 91.6 and 74.6%, respectively, after 24 h of digestion. In PRF clots associated with small and large red thrombi, platelet counts were 92.6 and 67.2% of the respective total platelet counts. These findings suggest that our direct method is sufficient for estimating the number of platelets trapped in an insoluble fibrin matrix and for determining that platelets are distributed in PRF clots and red thrombi roughly in proportion to their individual volumes. Therefore, we propose this direct digestion method for more accurate estimation of platelet counts in most types of platelet-enriched fibrin matrix. PMID:29450197

Profilin-Dependent Nucleation and Assembly of Actin Filaments Controls Cell Elongation in Arabidopsis1[OPEN

PubMed Central

Cao, Lingyan; Blanchoin, Laurent; Staiger, Christopher J.

2016-01-01

Actin filaments in plant cells are incredibly dynamic; they undergo incessant remodeling and assembly or disassembly within seconds. These dynamic events are choreographed by a plethora of actin-binding proteins, but the exact mechanisms are poorly understood. Here, we dissect the contribution of Arabidopsis (Arabidopsis thaliana) PROFILIN1 (PRF1), a conserved actin monomer-binding protein, to actin organization and single filament dynamics during axial cell expansion of living epidermal cells. We found that reduced PRF1 levels enhanced cell and organ growth. Surprisingly, we observed that the overall frequency of nucleation events in prf1 mutants was dramatically decreased and that a subpopulation of actin filaments that assemble at high rates was reduced. To test whether profilin cooperates with plant formin proteins to execute actin nucleation and rapid filament elongation in cells, we used a pharmacological approach. Here, we used Small Molecule Inhibitor of Formin FH2 (SMIFH2), after validating its mode of action on a plant formin in vitro, and observed a reduced nucleation frequency of actin filaments in live cells. Treatment of wild-type epidermal cells with SMIFH2 mimicked the phenotype of prf1 mutants, and the nucleation frequency in prf1-2 mutant was completely insensitive to these treatments. Our data provide compelling evidence that PRF1 coordinates the stochastic dynamic properties of actin filaments by modulating formin-mediated actin nucleation and assembly during plant cell expansion. PMID:26574597

Towards fast and accurate temperature mapping with proton resonance frequency-based MR thermometry

PubMed Central

Yuan, Jing; Mei, Chang-Sheng; Panych, Lawrence P.; McDannold, Nathan J.; Madore, Bruno

2012-01-01

The capability to image temperature is a very attractive feature of MRI and has been actively exploited for guiding minimally-invasive thermal therapies. Among many MR-based temperature-sensitive approaches, proton resonance frequency (PRF) thermometry provides the advantage of excellent linearity of signal with temperature over a large temperature range. Furthermore, the PRF shift has been shown to be fairly independent of tissue type and thermal history. For these reasons, PRF method has evolved into the most widely used MR-based thermometry method. In the present paper, the basic principles of PRF-based temperature mapping will be reviewed, along with associated pulse sequence designs. Technical advancements aimed at increasing the imaging speed and/or temperature accuracy of PRF-based thermometry sequences, such as image acceleration, fat suppression, reduced field-of-view imaging, as well as motion tracking and correction, will be discussed. The development of accurate MR thermometry methods applicable to moving organs with non-negligible fat content represents a very challenging goal, but recent developments suggest that this goal may be achieved. If so, MR-guided thermal therapies may be expected to play an increasingly-important therapeutic and palliative role, as a minimally-invasive alternative to surgery. PMID:22773966

Magnetic resonance thermometry for monitoring photothermal effects of interstitial laser irradiation

NASA Astrophysics Data System (ADS)

Goddard, Jessica; Jose, Jessnie; Figueroa, Daniel; Le, Kelvin; Liu, Hong; Nordquist, Robert E.; Hode, Tomas; Chen, Wei R.

2012-03-01

Selective photothermal interaction using dye-assisted non-invasive laser irradiation has limitations when treating deeper tumors or when the overlying skin is heavily pigmented. We developed an interstitial laser irradiation method to induce the desired photothermal effects. An 805-nm near-infrared laser with a cylindrical diffuser was used to treat rat mammary tumors by placing the active tip of the fiber inside the target tumors. Three different power settings (1.0 to 1.5 watts) were applied to treat animal tumors with an irradiation duration of 10 minutes. The temperature distributions of the treated tumors were measured by a 7.1-Tesla magnetic resonance imager using proton resonance frequency (PRF) method. Three-dimensional temperature profiles were reconstructed and assessed using PRF. This is the first time a 7.1-Tesla magnetic resonance imager has been used to monitor interstitial laser irradiation via PRF. This study provides a basic understanding of the photothermal interaction needed to control the thermal damage inside tumor using interstitial laser irradiation. It also shows that PRF can be used effectively in monitoring photothermal interaction. Our long-term goal is to develop a PRF-guided laser therapy for cancer treatment.

Pulse-to-pulse correlation in satellite radar altimeters. [for ocean wave height measurement

NASA Technical Reports Server (NTRS)

Walsh, E. J.

1982-01-01

Pulse-to-pulse correlation in satellite radar altimeters is examined to determine if range jitter in future altimeters could be reduced by increasing the pulse repetition frequency (PRF). Data from the Skylab radar altimeter is analyzed and compared with rules of thumb and the results of a Monte Carlo simulation. Altimeter range tracker configurations are reviewed and a simple curve is developed for the PRF below which decorrelation is assured. An adaptive PRF for future altimeters is recommended to conserve mission power while optimizing data collection during high-sea states.

Intermolecular hydrogen bonds in hetero-complexes of biologically active aromatic molecules probed by the methods of vibrational spectroscopy.

PubMed

Semenov, M A; Blyzniuk, Iu N; Bolbukh, T V; Shestopalova, A V; Evstigneev, M P; Maleev, V Ya

2012-09-01

By the methods of vibrational spectroscopy (Infrared and Raman) the investigation of the hetero-association of biologically active aromatic compounds: flavin-mononucleotide (FMN), ethidium bromide (EB) and proflavine (PRF) was performed in aqueous solutions. It was shown that between the functional groups (CO and NH(2)) the intermolecular hydrogen bonds are formed in the hetero-complexes FMN-EB and FMN-PRF, additionally stabilizing these structures. An estimation of the enthalpy of Н-bonding obtained from experimental shifts of carbonyl vibrational frequencies has shown that the H-bonds do not dominate in the magnitude of experimentally measured total enthalpy of the hetero-association reactions. The main stabilization is likely due to intermolecular interactions of the molecules in these complexes and their interaction with water environment. Copyright © 2012 Elsevier B.V. All rights reserved.

The effect of platelet rich fibrin on growth factor levels in urethral repair.

PubMed

Soyer, Tutku; Ayva, Şebnem; Boybeyi, Özlem; Aslan, Mustafa Kemal; Çakmak, Murat

2013-12-01

Platelet rich fibrin (PRF) is an autologous source of growth factors and promotes wound healing. An experimental study was performed to evaluate the effect of PRF on growth factor levels in urethral repair. Eighteen Wistar albino rats were included in the study. Rats were allocated in three groups (n:6): control (CG), sham (SG), and PRF (PRFG). In SG, a 5 mm vertical incision was performed in the penile urethra and repaired with 10/0 Vicryl® under a microscope. In PRFG, during the urethral repair as described in SG, 1 cc of blood was sampled from each rat and centrifuged for 10 minutes at 2400 rpm. PRF obtained from the centrifugation was placed on the repair site during closure. Penile urethras were sampled 24 hours after PRF application in PRFG and after urethral repair in SG. Transforming growth factor beta receptor (TGF-β-R-CD105), vascular endothelial growth factor (VEGF) and its receptor (VEGF-R), as well as endothelial growth factor receptor (EGFR), were evaluated in subepithelia of the penile skin and urethra. Groups were compared for growth factor levels and growth factor receptor expression with the Kruskal Wallis test. TGF-β-R levels were significantly decreased in SG when compared to CG (p<0.05). In PRFG, TGF-β-R was increased in both subepithelia of penile skin and urethra with respect to SG (p<0.05). When VEGF levels and its receptor expression were compared between SG and PRFG, VEGF levels were found to be increased in penile skin subepithelium, whereas VEGF-R expressions were decreased in urethral subepithelia in PRFG (p<0.05). There was no difference between groups for EGFR levels (p>0.05). Use of PRF after urethral repair increases TGF-β-R and VEGF expressions in urethral tissue. PRF can be considered as an alternative measure to improve the success of urethral repair. © 2013.

Platelet-Rich Fibrin and Soft Tissue Wound Healing: A Systematic Review.

PubMed

Miron, Richard J; Fujioka-Kobayashi, Masako; Bishara, Mark; Zhang, Yufeng; Hernandez, Maria; Choukroun, Joseph

2017-02-01

The growing multidisciplinary field of tissue engineering aims at predictably regenerating, enhancing, or replacing damaged or missing tissues for a variety of conditions caused by trauma, disease, and old age. One area of research that has gained tremendous awareness in recent years is that of platelet-rich fibrin (PRF), which has been utilized across a wide variety of medical fields for the regeneration of soft tissues. This systematic review gathered all the currently available in vitro, in vivo, and clinical literature utilizing PRF for soft tissue regeneration, augmentation, and/or wound healing. In total, 164 publications met the original search criteria, with a total of 48 publications meeting inclusion criteria (kappa score = 94%). These studies were divided into 7 in vitro, 11 in vivo, and 31 clinical studies. In summary, 6 out of 7 (85.7%) and 11 out of 11 (100%) of the in vitro and in vivo studies, respectively, demonstrated a statistically significant advantage for combining PRF to their regenerative therapies. Out of the remaining 31 clinical studies, a total of 8 reported the effects of PRF in a randomized clinical trial, with 5 additional studies (13 total) reporting appropriate controls. In those clinical studies, 9 out of the 13 studies (69.2%) demonstrated a statistically relevant positive outcome for the primary endpoints measured. In total, 18 studies (58% of clinical studies) reported positive wound-healing events associated with the use of PRF, despite using controls. Furthermore, 27 of the 31 clinical studies (87%) supported the use of PRF for soft tissue regeneration and wound healing for a variety of procedures in medicine and dentistry. In conclusion, the results from the present systematic review highlight the positive effects of PRF on wound healing after regenerative therapy for the management of various soft tissue defects found in medicine and dentistry.

Pulsed Compared to Thermal Radiofrequency to the Medial Calcaneal Nerve for Management of Chronic Refractory Plantar Fasciitis: A Prospective Comparative Study.

PubMed

Osman, Ayman M; El-Hammady, Dina H; Kotb, Mohamed M

2016-01-01

Radiofrequency (RF) treatment is a minimally invasive procedure that has been used for more than 3 decades in treating various chronic pain syndromes. Conventional (continuous) RF treatment occasionally results in worsening or even initiating a new type of pain. The use of pulsed radiofrequency (PRF), which has a non- or minimally neurodestructive neuromodulatory effect, serves as an alternative to conventional RF therapy in many medical situations. To evaluate the effect of applying PRF for 6 minutes vs. thermal radiofrequency (TRF) for 90 seconds to the medial calcaneal nerve for treatment of chronic refractory plantar fasciitis pain. Prospective comparative study. Pain, Orthopedic, and Rheumatology and Rehabilitation Clinics of Assiut University Hospital. Twenty patients with refractory chronic bilateral plantar fasciitis received PRF to the medial calcaneal nerve for 6 minutes for one heel and TRF to the same nerve on the other heel (as their own control) for 90 seconds. Numerical verbal rating scale (NVRS) at waking up from bed and after prolonged walking, and satisfaction score were used for assessment of studied patients at one, 3, 6, 12, and 24 weeks from the intervention. All studied patients showed significant improvement in their pain scale after the intervention that lasted for 24 weeks; however, the PRF heels had significantly better pain scale and satisfaction scores at the first and third weeks assessments when compared to the TRF heels. Effective analgesia was achieved after one week or less after PRF compared to 3 weeks for the TRF (P < 0.001). No randomization. PRF to the medial calcaneal nerve is a safe and effective method for treatment of chronic plantar fasciitis pain. The onset of effective analgesia can be achieved more rapidly with PRF compared to TRF on the same nerve. Further randomized trials are needed to confirm the therapeutic effect and optimizing the dose of RF needed.Key words: Pulsed radiofrequency, thermal radiofrequency, medial calcaneal nerve, plantar fasciitis, plantar aponeurosis, visual analogue scale.

Pulsed Radiofrequency Application for the Treatment of Pain Secondary to Sacroiliac Joint Metastases.

PubMed

Yi, Yu Ri; Lee, Na Rea; Kwon, Young Suk; Jang, Ji Su; Lim, So Young

2016-01-01

Sacroiliac (SI) joint pain can result from degeneration, infection, malignancy, and trauma. Patients with metastatic bone pain who do not respond to conventional treatment may need more aggressive neuroinvasive approaches. Recently, pulsed radiofrequency (PRF) neuromodulation has emerged as a promising treatment alternative for refractory cases of SI joint pain. Nevertheless, there is no report on the treatment of pain arising from SI joint metastases with PRF. We are reporting about a 63-year-old woman suffering from buttock pain due to breast cancer metastases in the SI joint. We treated this patient with PRF neuromodulation of the L4-S3 primary dorsal rami and lateral branches using a rotating curved needle technique. The patient tolerated the procedures well, without any complications. She experienced about 70% reduction in pain, and pain relief was sustained for 10 months. This result suggests that PRF neuromodulation is a safe, effective treatment for pain from SI joint metastases.

Management of bisphosphonate-related osteonecrosis of the jaw with a platelet-rich fibrin membrane: technical report.

PubMed

Soydan, Sıdıka Sinem; Uckan, Sina

2014-02-01

Bisphosphonate-related osteonecrosis of the jaw (BRONJ) is a challenging complication resulting from the long-term application of bisphosphonates. In most cases, BRONJ occurs after a surgical procedure involving the jawbone. Currently, the management of BRONJ remains controversial, and there is no definitive treatment other than palliative methods. Platelet-rich fibrin (PRF) represents a relatively new biotechnology for the stimulation and acceleration of tissue healing and bone regeneration. This technical note describes the total closure of moderate bone exposure in persistent BRONJ in 2 weeks with a double-layer PRF membrane. PRF may stimulate gingival healing and act as a barrier membrane between the alveolar bone and the oral cavity. PRF may offer a fast, easy, and effective alternative method for the closure of bone exposure in BRONJ. Copyright © 2014 American Association of Oral and Maxillofacial Surgeons. Published by Elsevier Inc. All rights reserved.

Development and Validation of a Monte Carlo Simulation Tool for Multi-Pinhole SPECT

PubMed Central

Mok, Greta S. P.; Du, Yong; Wang, Yuchuan; Frey, Eric C.; Tsui, Benjamin M. W.

2011-01-01

Purpose In this work, we developed and validated a Monte Carlo simulation (MCS) tool for investigation and evaluation of multi-pinhole (MPH) SPECT imaging. Procedures This tool was based on a combination of the SimSET and MCNP codes. Photon attenuation and scatter in the object, as well as penetration and scatter through the collimator detector, are modeled in this tool. It allows accurate and efficient simulation of MPH SPECT with focused pinhole apertures and user-specified photon energy, aperture material, and imaging geometry. The MCS method was validated by comparing the point response function (PRF), detection efficiency (DE), and image profiles obtained from point sources and phantom experiments. A prototype single-pinhole collimator and focused four- and five-pinhole collimators fitted on a small animal imager were used for the experimental validations. We have also compared computational speed among various simulation tools for MPH SPECT, including SimSET-MCNP, MCNP, SimSET-GATE, and GATE for simulating projections of a hot sphere phantom. Results We found good agreement between the MCS and experimental results for PRF, DE, and image profiles, indicating the validity of the simulation method. The relative computational speeds for SimSET-MCNP, MCNP, SimSET-GATE, and GATE are 1: 2.73: 3.54: 7.34, respectively, for 120-view simulations. We also demonstrated the application of this MCS tool in small animal imaging by generating a set of low-noise MPH projection data of a 3D digital mouse whole body phantom. Conclusions The new method is useful for studying MPH collimator designs, data acquisition protocols, image reconstructions, and compensation techniques. It also has great potential to be applied for modeling the collimator-detector response with penetration and scatter effects for MPH in the quantitative reconstruction method. PMID:19779896

Efficacy of Platelet-Rich Fibrin After Mandibular Third Molar Extraction: A Systematic Review and Meta-Analysis.

PubMed

Al-Hamed, Faez Saleh; Tawfik, Mohamed Abdel-Monem; Abdelfadil, Ehab; Al-Saleh, Mohammed A Q

2017-06-01

To assess the effect of platelet-rich fibrin (PRF) on the healing process of the alveolar socket after surgical extraction of the mandibular third molars. PubMed, the Cochrane Central Register of Controlled Trials, Scopus, and relevant journals were searched using a combination of specific keywords ("platelet-rich fibrin," "oral surgery," and "third molar"). The final search was conducted on November 2, 2015. Randomized controlled clinical trials, as well as controlled clinical trials, aimed at comparing the effect of PRF versus natural healing after extraction of mandibular third molars were included. Five randomized controlled trials and one controlled clinical trial were included. There were 335 extractions (168 with PRF and 167 controls) in 183 participants. Considerable heterogeneity in study characteristics, outcome variables, and estimated scales was observed. Positive results were generally recorded for pain, trismus, swelling, periodontal pocket depth, soft tissue healing, and incidence of localized osteitis, but not in all studies. However, no meta-analysis could be conducted for such variables because of the different measurement scales used. The qualitative and meta-analysis results showed no significant improvement in bone healing with PRF-treated sockets compared with the naturally healing sockets. Within the limitations of the available evidence, PRF seems to have no beneficial role in bone healing after extraction of the mandibular third molars. Future standardized randomized controlled clinical trials are required to estimate the effect of PRF on socket regeneration. Copyright © 2017 American Association of Oral and Maxillofacial Surgeons. Published by Elsevier Inc. All rights reserved.

A randomized comparative prospective study of platelet-rich plasma, platelet-rich fibrin, and hydroxyapatite as a graft material for mandibular third molar extraction socket healing.

PubMed

Dutta, Shubha Ranjan; Passi, Deepak; Singh, Purnima; Sharma, Sarang; Singh, Mahinder; Srivastava, Dhirendra

2016-01-01

The purpose of this study was to compare the efficacy of platelet-rich plasma (PRP), platelet-rich fibrin (PRF), and hydroxyapatite (HA) for reduction of pain and swelling, absence of dry socket, soft tissue healing, and bone regeneration after mandibular third molar extraction in human patients. Forty patients requiring extraction of mandibular third molars were randomly grouped as control, PRP, PRF, and HA-treated. The patients were assessed for postoperative pain, swelling, dry socket, and soft tissue healing on the 3 rd , 7 th , and 14 th day of postoperative periods depending on the standard methods. Radiological assessment of the extraction site was done at 1, 2, and 6 months interval to compare the change in bone density in the sockets in control and treated patients. Pain and swelling were less on PRP and PRF site when compared to HA and control site. PRP and PRF site showed better soft tissue healing when compared to HA and control site. Radiographic assessment showed comparatively lesser bone density values in PRP, PRF, and control site at 1, 2, and 6 months than HA site. Our study showed that PRP and PRF are better graft materials than HA regarding pain, swelling, dry socket, and soft tissue healing. Bone regeneration is induced promptly by HA as compared to other graft materials. However, a more elaborate study with a larger number of clinical cases is very much essential to be more conclusive regarding the efficacy of the graft materials.

Platelet rich fibrin in the management of established dry socket.

PubMed

Chakravarthi, Srinivas

2017-06-01

Dry socket may occur secondary to the removal of any tooth. However, most dry socket cases develop in the third molar region. Dry socket is multifactorial in nature and has been treated using various modalities with varying success rates. This study assessed the efficacy of platelet rich fibrin (PRF) in established dry socket. Ten patients of either sex aged from 41 to 64 years with established dry socket according to established criteria were treated using PRF. Evaluation was performed by observing the reduction of pain using visual analogue scale, analgesic tablet use over the follow-up period, and healing parameters. Pain was reduced on the first day in all patients with decreased analgesic use. Pain was drastically reduced during follow-up on the first, second, third, and seventh days with a fall in pain score of 0 to 1 after the first day alone. The pain scores of all patients decreased to 1 by the first day except in one patient, and the scores decreased to 0 in all patients after 48 hours. Total analgesic intake ranged from 2 to 6 tablets (aceclofenac 100 mg per tablet) over the follow-up period of 7 days. Healing was satisfactory in all patients by the end of the seventh day. PRF showed early pain reduction in established dry socket with minimal analgesic intake. No patients had allergic reactions to PRF as it is derived from the patient's own blood. PRF showed good wound healing. Our study suggests that PRF should be considered as a treatment modality for established dry socket.

Effectiveness of platelet-rich fibrin in the management of pain and delayed wound healing associated with established alveolar osteitis (dry socket).

PubMed

Sharma, Ashish; Aggarwal, Nimish; Rastogi, Sanjay; Choudhury, Rupshikha; Tripathi, Siddhi

2017-01-01

To assess the efficacy of platelet-rich fibrin (PRF) on the pain and healing of the extraction socket related with established alveolar osteitis (dry socket, AO) after the removal of maxillary and mandibular molars. One hundred consecutive adult patients with age group ranging from 18 to 40 years along with established dry socket after maxillary and mandibular molar extractions who have not received any treatment for the same were included in this single-arm clinical trial. PRF was placed in the maxillary and mandibular molar extraction sockets after adequate irrigation of the socket. All the patients evaluated for the various study variables which include pain, degree of inflammation, and healthy granulation tissue formation (wound healing) at the 1 st , 3 rd , 7 th , and 14 th post-PRF placement day in the alveolar socket. Data were analyzed using Shapiro-Wilk's test, Chi-square test and/or Student's t -test, Friedman's test, Wilcoxon signed-rank test, and Bonferroni test, with the significance level set at P < 0.05. There was significant reduction in pain associated with AO at the 3 rd and 7 th post-PRF placement day in the extraction socket along with mark decrease in the degree of inflammation at the 3 rd post-PRF placement day, and there was better wound healing by the end of the 2 nd week. The use of PRF in this clinical trial illustrates the promising results in terms of reduced pain and better healing in the patients with sustained AO.

Platelet rich fibrin in the management of established dry socket

PubMed Central

2017-01-01

Objectives Dry socket may occur secondary to the removal of any tooth. However, most dry socket cases develop in the third molar region. Dry socket is multifactorial in nature and has been treated using various modalities with varying success rates. This study assessed the efficacy of platelet rich fibrin (PRF) in established dry socket. Materials and Methods Ten patients of either sex aged from 41 to 64 years with established dry socket according to established criteria were treated using PRF. Evaluation was performed by observing the reduction of pain using visual analogue scale, analgesic tablet use over the follow-up period, and healing parameters. Results Pain was reduced on the first day in all patients with decreased analgesic use. Pain was drastically reduced during follow-up on the first, second, third, and seventh days with a fall in pain score of 0 to 1 after the first day alone. The pain scores of all patients decreased to 1 by the first day except in one patient, and the scores decreased to 0 in all patients after 48 hours. Total analgesic intake ranged from 2 to 6 tablets (aceclofenac 100 mg per tablet) over the follow-up period of 7 days. Healing was satisfactory in all patients by the end of the seventh day. Conclusion PRF showed early pain reduction in established dry socket with minimal analgesic intake. No patients had allergic reactions to PRF as it is derived from the patient's own blood. PRF showed good wound healing. Our study suggests that PRF should be considered as a treatment modality for established dry socket. PMID:28770156

Soft-Tissue Grafting Techniques Associated With Immediate Implant Placement.

PubMed

Bishara, Mark; Kurtzman, Gregori M; Khan, Waji; Choukroun, Joseph; Miron, Richard J

2018-02-01

Immediate implant placement often presents challenges in terms of predictably obtaining soft-tissue coverage over the implant site. While delayed implant placement offers the ability for soft tissues to grow and invade the extraction socket making their attachment around implants more predictable, immediate implant placement poses a significant risk of bacterial invasion towards the implant surface as a result of insignificant soft-tissue volume. Soft-tissue grafting techniques have often been proposed for use during immediate implant placement to augment soft-tissue deficiencies, including the use of either palatal connective tissue grafts (CTGs) or collagen-derived scaffolds. However, both of these approaches have significant drawbacks in that CTGs are harvested with high patient morbidity and collagen scaffolds remain avascular and acelluar posing a risk of infection/implant contamination. More recently, platelet-rich fibrin (PRF) has been proposed as an economical and biological means to speed soft-tissue wound healing. In combination with immediate implant placement, PRF offers an easily procurable low-cost regenerative modality that offers an efficient way to improve soft-tissue attachment around implants. Furthermore, the supra-physiological concentration of defense-fighting leukocytes in PRF, combined with a dense fibrin meshwork, is known to prevent early bacterial contamination of implant surfaces, and the biological concentrations of autologous growth factors in PRF is known to increase tissue regeneration. This article discusses soft-tissue grafting techniques associated with immediate implant placement, presents several cases demonstrating the use of PRF in routine immediate implant placement, and further discusses the biological and economic advantages of PRF for the management of soft-tissue grafting during immediate implant placement.

Efficacy of pulsed radiofrequency medial branch treatment in low back pain patients.

PubMed

Kim, Do Hyoung; Han, Seong Rok; Choi, Chan Young; Sohn, Moon Jun; Lee, Chae Heuck

2016-04-27

It was thought that the efficacy of pulsed radiofrequency (PRF) treatment of the medial branch in patients with lower back pain was not as long lasting as that of continuous radiofrequency (CRF) thermo-coagulation techniques. The goal of this study was to determine the efficacy and the long-term effects of PRF treatment of the medial branch in selected low back pain patients. We retrospectively reviewed and analyzed patients with lower back pain who underwent PRF treatment on the medial branch at our institute. Pain relief was evaluated by visual analog scale (VAS) score at pretreatment, 2 weeks, 6 months, 1 year and 2 years post-treatment. Oswestry disability index (ODI) score was evaluated pretreatment and at 2 years post-treatment. We also recorded the satisfaction period after PRF treatment. Twenty-three patients were available for the 2-year follow-up analysis. None of the patients had any side effects or procedure-related complications during the follow up period. The average VAS score declined from 7.1 ± 2.4 pre-treatment to 2.9 ± 2.1 2 weeks post-treatment, 2.6 ± 1.8 at 6 months, 2.8 ± 2.1 at 1 year and 3.0 ± 2.5 at 2 years. The average ODI score decreased from 33.6 ± 13.6 pre-treatment to 15.3 ± 5.7 at 2 years post-treatment. Mean satisfaction period after PRF treatment was 16.6 ± 9.43 months. PRF treatment on the medial branch is an effective and safe treatment option for patients with lower back pain.

Management of refractory trigeminal neuralgia using extended duration pulsed radiofrequency application.

PubMed

Thapa, Deepak; Ahuja, Vanita; Dass, Christopher; Verma, Parul

2015-01-01

Trigeminal neuralgia (TN) produces incapacitating facial pain that reduces quality of life in patients. Thermal radiofrequency (RF) ablation of gasserian ganglion (GG) is associated with masseter weakness and unpleasant sensations along the distribution of the ablated nerve. Pulsed radiofrequency (PRF) of GG has minimal side effects but literature is inconclusive regarding its benefit in refractory TN. Increasing the duration of PRF application to 6 minutes in TN produced encouraging results. PRF application to the saphenous nerve for 8 minutes reported improved pain relief and patient satisfaction. We report successful management of two patients of classic TN, which were refractory to medical management and interventional nerve blocks. The lesion site were confirmed with motor and sensory stimulation through a 22 G, 10 cm RF needle with 5 mm active tip. Both the patients received four cycles of PRF at 42 °C with each cycle of 120 seconds (8 minutes). The visual analogue scale (VAS) in case 1 reduced from pre-block score of 80 to score 10 post-block, while in case 2 the VAS reduced from pre-block score of 85 to score 15 post-block. During follow up both the patients are now pain free with minimal dose of carbamazepine at 12 and 6 months respectively. We used PRF for longer duration (8 minutes) in these patients, which resulted in improved VAS and WHOQOL-BREF score in these patients. PRF of mandibular division of GG for extended duration provided long-term effective pain relief and quality of life in patients of refractory classic TN.

A randomized comparative prospective study of platelet-rich plasma, platelet-rich fibrin, and hydroxyapatite as a graft material for mandibular third molar extraction socket healing

PubMed Central

Dutta, Shubha Ranjan; Passi, Deepak; Singh, Purnima; Sharma, Sarang; Singh, Mahinder; Srivastava, Dhirendra

2016-01-01

Aim: The purpose of this study was to compare the efficacy of platelet-rich plasma (PRP), platelet-rich fibrin (PRF), and hydroxyapatite (HA) for reduction of pain and swelling, absence of dry socket, soft tissue healing, and bone regeneration after mandibular third molar extraction in human patients. Materials and Methods: Forty patients requiring extraction of mandibular third molars were randomly grouped as control, PRP, PRF, and HA-treated. The patients were assessed for postoperative pain, swelling, dry socket, and soft tissue healing on the 3rd, 7th, and 14th day of postoperative periods depending on the standard methods. Radiological assessment of the extraction site was done at 1, 2, and 6 months interval to compare the change in bone density in the sockets in control and treated patients. Results: Pain and swelling were less on PRP and PRF site when compared to HA and control site. PRP and PRF site showed better soft tissue healing when compared to HA and control site. Radiographic assessment showed comparatively lesser bone density values in PRP, PRF, and control site at 1, 2, and 6 months than HA site. Conclusion: Our study showed that PRP and PRF are better graft materials than HA regarding pain, swelling, dry socket, and soft tissue healing. Bone regeneration is induced promptly by HA as compared to other graft materials. However, a more elaborate study with a larger number of clinical cases is very much essential to be more conclusive regarding the efficacy of the graft materials. PMID:28163478

Shallow-depth location and geometry of the Piedmont Reverse splay of the Hayward Fault, Oakland, California

USGS Publications Warehouse

Catchings, Rufus D.; Goldman, Mark R.; Trench, David; Buga, Michael; Chan, Joanne H.; Criley, Coyn J.; Strayer, Luther M.

2017-04-18

The Piedmont Thrust Fault, herein referred to as the Piedmont Reverse Fault (PRF), is a splay of the Hayward Fault that trends through a highly populated area of the City of Oakland, California (fig. 1A). Although the PRF is unlikely to generate a large-magnitude earthquake, slip on the PRF or high-amplitude seismic energy traveling along the PRF may cause considerable damage during a large earthquake on the Hayward Fault. Thus, it is important to determine the exact location, geometry (particularly dip), and lateral extent of the PRF within the densely populated Oakland area. In the near surface, the PRF juxtaposes Late Cretaceous sandstone (of the Franciscan Complex Novato Quarry terrane of Blake and others, 1984) and an older Pleistocene alluvial fan unit along much of its mapped length (fig. 1B; Graymer and others, 1995). The strata of the Novato Quarry unit vary greatly in strike (NW, NE, and E), dip direction (NE, SW, E, and NW), dip angle (15° to 85°), and lithology (shale and sandstone), and the unit has been intruded by quartz diorite in places. Thus, it is difficult to infer the structure of the fault, particularly at depth, with conventional seismic reflection imaging methods. To better determine the location and shallow-depth geometry of the PRF, we used high-resolution seismic imaging methods described by Catchings and others (2014). These methods involve the use of coincident P-wave (compressional wave) and S-wave (shear wave) refraction tomography and reflection data, from which tomographic models of P- and S-wave velocity and P-wave reflection images are developed. In addition, the coincident P-wave velocity (VP) and S-wave velocity (VS) data are used to develop tomographic models of VP/VS ratios and Poisson’s ratio, which are sensitive to shallow-depth faulting and groundwater. In this study, we also compare measurements of Swave velocities determined from surface waves with those determined from refraction tomography. We use the combination of seismic methods to infer the fault location, dip, and the National Earthquake Hazards Reduction Program (NEHRP) site classification along the seismic profile. Our seismic study is a smaller part of a larger study of the PRF by Trench and others (2016).

Spectroscopic and chemical-kinetic analysis of the phases of HCCI autoignition and combustion for single- and two-stage ignition fuels

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hwang, Wontae; Dec, John; Sjoeberg, Magnus

The temporal phases of autoignition and combustion in an HCCI engine have been investigated in both an all-metal engine and a matching optical engine. Gasoline, a primary reference fuel mixture (PRF80), and several representative real-fuel constituents were examined. Only PRF80, which is a two-stage ignition fuel, exhibited a ''cool-flame'' low-temperature heat-release (LTHR) phase. For all fuels, slow exothermic reactions occurring at intermediate temperatures raised the charge temperature to the hot-ignition point. In addition to the amount of LTHR, differences in this intermediate-temperature heat-release (ITHR) phase affect the fuel ignition quality. Chemiluminescence images of iso-octane show a weak and uniform lightmore » emission during this phase. This is followed by the main high-temperature heat-release (HTHR) phase. Finally, a ''burnout'' phase was observed, with very weak uniform emission and near-zero heat-release rate (HRR). To better understand these combustion phases, chemiluminescence spectroscopy and chemical-kinetic analysis were applied for the single-stage ignition fuel, iso-octane, and the two-stage fuel, PRF80. For both fuels, the spectrum obtained during the ITHR phase was dominated by formaldehyde chemiluminescence. This was similar to the LTHR spectrum of PRF80, but the emission intensity and the temperature were much higher, indicating differences between the ITHR and LTHR phases. Chemical-kinetic modeling clarified the differences and similarities between the LTHR and ITHR phases and the cause of the enhanced ITHR with PRF80. The HTHR spectra for both fuels were dominated by a broad CO continuum with some contribution from bands of HCO, CH, and OH. The modeling showed that the CO+ O{yields}CO{sub 2}+h{nu} reaction responsible for the CO continuum emission tracks the HTHR well, explaining the strong correlation observed experimentally between the total chemiluminescence and HRR during the HTHR phase. It also showed that the CO continuum does not contribute to the ITHR and LTHR chemiluminescence. Bands of H{sub 2}O and O{sub 2} in the red and IR regions were also detected during the HTHR, which the data indicated were most likely due to thermal excitation. The very weak light emission in the ''burnout'' phase also appeared to be thermal emission from H{sub 2}O and O{sub 2}. (author)« less

Thermochemical and Physical Properties of Fluids, Lubricants and Related Materials. Delivery Order 0001 : Improved Methods Development for Determining Thermophysical and Thermochemical Properties of Fluids, Lubricants and Related Materials

DTIC Science & Technology

2008-07-01

PRF-5606H, ...................76 FTM 791C, method 36003) 168 hrs. @ 70ºC using NBR -L (AMS3217/2B Rubber specimens. 42. MLO-06...0275: Rubber Swell Test (MIL-PRF-5606H, .................77 FTM 791C, method 3603) 168 hrs. @ 70ºC using NBR -L...NUMBER MLO-05-421 Rubber Swell Test (MIL-PRF-5606H, FTM 791C, method 36003) 168 Hours @ 70°C (158°F) using NBR -L(AMS 3217/2B) rubber specimens

Ultra-wideband short-pulse radar with range accuracy for short range detection

DOEpatents

Rodenbeck, Christopher T; Pankonin, Jeffrey; Heintzleman, Richard E; Kinzie, Nicola Jean; Popovic, Zorana P

2014-10-07

An ultra-wideband (UWB) radar transmitter apparatus comprises a pulse generator configured to produce from a sinusoidal input signal a pulsed output signal having a series of baseband pulses with a first pulse repetition frequency (PRF). The pulse generator includes a plurality of components that each have a nonlinear electrical reactance. A signal converter is coupled to the pulse generator and configured to convert the pulsed output signal into a pulsed radar transmit signal having a series of radar transmit pulses with a second PRF that is less than the first PRF.

Complex-Difference Constrained Compressed Sensing Reconstruction for Accelerated PRF Thermometry with Application to MRI Induced RF Heating

PubMed Central

Cao, Zhipeng; Oh, Sukhoon; Otazo, Ricardo; Sica, Christopher T.; Griswold, Mark A.; Collins, Christopher M.

2014-01-01

Purpose Introduce a novel compressed sensing reconstruction method to accelerate proton resonance frequency (PRF) shift temperature imaging for MRI induced radiofrequency (RF) heating evaluation. Methods A compressed sensing approach that exploits sparsity of the complex difference between post-heating and baseline images is proposed to accelerate PRF temperature mapping. The method exploits the intra- and inter-image correlations to promote sparsity and remove shared aliasing artifacts. Validations were performed on simulations and retrospectively undersampled data acquired in ex-vivo and in-vivo studies by comparing performance with previously proposed techniques. Results The proposed complex difference constrained compressed sensing reconstruction method improved the reconstruction of smooth and local PRF temperature change images compared to various available reconstruction methods in a simulation study, a retrospective study with heating of a human forearm in vivo, and a retrospective study with heating of a sample of beef ex vivo . Conclusion Complex difference based compressed sensing with utilization of a fully-sampled baseline image improves the reconstruction accuracy for accelerated PRF thermometry. It can be used to improve the volumetric coverage and temporal resolution in evaluation of RF heating due to MRI, and may help facilitate and validate temperature-based methods for safety assurance. PMID:24753099

Staggered Multiple-PRF Ultrafast Color Doppler.

PubMed

Posada, Daniel; Poree, Jonathan; Pellissier, Arnaud; Chayer, Boris; Tournoux, Francois; Cloutier, Guy; Garcia, Damien

2016-06-01

Color Doppler imaging is an established pulsed ultrasound technique to visualize blood flow non-invasively. High-frame-rate (ultrafast) color Doppler, by emissions of plane or circular wavefronts, allows severalfold increase in frame rates. Conventional and ultrafast color Doppler are both limited by the range-velocity dilemma, which may result in velocity folding (aliasing) for large depths and/or large velocities. We investigated multiple pulse-repetition-frequency (PRF) emissions arranged in a series of staggered intervals to remove aliasing in ultrafast color Doppler. Staggered PRF is an emission process where time delays between successive pulse transmissions change in an alternating way. We tested staggered dual- and triple-PRF ultrafast color Doppler, 1) in vitro in a spinning disc and a free jet flow, and 2) in vivo in a human left ventricle. The in vitro results showed that the Nyquist velocity could be extended to up to 6 times the conventional limit. We found coefficients of determination r(2) ≥ 0.98 between the de-aliased and ground-truth velocities. Consistent de-aliased Doppler images were also obtained in the human left heart. Our results demonstrate that staggered multiple-PRF ultrafast color Doppler is efficient for high-velocity high-frame-rate blood flow imaging. This is particularly relevant for new developments in ultrasound imaging relying on accurate velocity measurements.

Does temperature nudging overwhelm aerosol radiative ...

EPA Pesticide Factsheets

For over two decades, data assimilation (popularly known as nudging) methods have been used for improving regional weather and climate simulations by reducing model biases in meteorological parameters and processes. Similar practice is also popular in many regional integrated meteorology-air quality models that include aerosol direct and indirect effects. However in such multi-modeling systems, temperature changes due to nudging can compete with temperature changes induced by radiatively active & hygroscopic short-lived tracers leading to interesting dilemmas: From weather and climate prediction’s (retrospective or future) point of view when nudging is continuously applied, is there any real added benefit of using such complex and computationally expensive regional integrated modeling systems? What are the relative sizes of these two competing forces? To address these intriguing questions, we convert temperature changes due to nudging into radiative fluxes (referred to as the pseudo radiative forcing, PRF) at the surface and troposphere, and compare the net PRF with the reported aerosol radiative forcing. Results indicate that the PRF at surface dominates PRF at top of the atmosphere (i.e., the net). Also, the net PRF is about 2-4 times larger than estimated aerosol radiative forcing at regional scales while it is significantly larger at local scales. These results also show large surface forcing errors at many polluted urban sites. Thus, operational c

Comparison of Bovine Bone-Autogenic Bone Mixture Versus Platelet-Rich Fibrin for Maxillary Sinus Grafting: Histologic and Histomorphologic Study.

PubMed

Ocak, Hakan; Kutuk, Nukhet; Demetoglu, Umut; Balcıoglu, Esra; Ozdamar, Saim; Alkan, Alper

2017-06-01

Numerous grafting materials have been used to augment the maxillary sinus floor for long-term stability and success for implant-supported prosthesis. To enhance bone formation, adjunctive blood-born growth factor sources have gained popularity during the recent years. The present study compared the use of platelet-rich fibrin (PRF) and bovine-autogenous bone mixture for maxillary sinus floor elevation. A split-face model was used to apply 2 different filling materials for maxillary sinus floor elevation in 22 healthy adult sheep. In group 1, bovine and autogenous bone mixture; and in group 2, PRF was used. The animals were killed at 3, 6, and 9 months. Histologic and histomorphologic examinations revealed new bone formation in group 1 at the third and sixth months. In group 2, new bone formation was observed only at the sixth month, and residual PRF remnants were identified. At the ninth month, host bone and new bone could not be distinguished from each other in group 1, and bone formation was found to be proceeding in group 2. PRF remnants still existed at the ninth month. In conclusion, bovine bone and autogenous bone mixture is superior to PRF as a grafting material in sinus-lifting procedures.

Redox proteomics of tomato in response to Pseudomonas syringae infection

PubMed Central

Balmant, Kelly Mayrink; Parker, Jennifer; Yoo, Mi-Jeong; Zhu, Ning; Dufresne, Craig; Chen, Sixue

2015-01-01

Unlike mammals with adaptive immunity, plants rely on their innate immunity based on pattern-triggered immunity (PTI) and effector-triggered immunity (ETI) for pathogen defense. Reactive oxygen species, known to play crucial roles in PTI and ETI, can perturb cellular redox homeostasis and lead to changes of redox-sensitive proteins through modification of cysteine sulfhydryl groups. Although redox regulation of protein functions has emerged as an important mechanism in several biological processes, little is known about redox proteins and how they function in PTI and ETI. In this study, cysTMT proteomics technology was used to identify similarities and differences of protein redox modifications in tomato resistant (PtoR) and susceptible (prf3) genotypes in response to Pseudomonas syringae pv tomato (Pst) infection. In addition, the results of the redox changes were compared and corrected with the protein level changes. A total of 90 potential redox-regulated proteins were identified with functions in carbohydrate and energy metabolism, biosynthesis of cysteine, sucrose and brassinosteroid, cell wall biogenesis, polysaccharide/starch biosynthesis, cuticle development, lipid metabolism, proteolysis, tricarboxylic acid cycle, protein targeting to vacuole, and oxidation–reduction. This inventory of previously unknown protein redox switches in tomato pathogen defense lays a foundation for future research toward understanding the biological significance of protein redox modifications in plant defense responses. PMID:26504582

Suppressing bubble shielding effect in shock wave lithotripsy by low intensity pulsed ultrasound.

PubMed

Wang, Jen-Chieh; Zhou, Yufeng

2015-01-01

Extracorporeal shock wave lithotripsy (ESWL) has been used as an effective modality to fragment kidney calculi. Because of the bubble shielding effect in the pre-focal region, the acoustic energy delivered to the focus is reduced. Low pulse repetition frequency (PRF) will be applied to dissolve these bubbles for better stone comminution efficiency. In this study, low intensity pulsed ultrasound (LIPUS) beam was aligned perpendicular to the axis of a shock wave (SW) lithotripter at its focus. The light transmission was used to evaluate the compressive wave and cavitation induced by SWs without or with a combination of LIPUS for continuous sonication. It is found that bubble shielding effect becomes dominated with the SW exposure and has a greater significant effect on cavitation than compressive wave. Using the combined wave scheme, the improvement began at the 5th pulse and gradually increased. Suppression effect on bubble shielding is independent on the trigger delay, but increases with the acoustic intensity and pulse duration of LIPUS. The peak negative and integral area of light transmission signal, which present the compressive wave and cavitation respectively, using our strategy at PRF of 1 Hz are comparable to those using SW alone at PRF of 0.1 Hz. In addition, high-speed photography confirmed the bubble activities in both free field and close to a stone surface. Bubble motion in response to the acoustic radiation force by LIPUS was found to be the major mechanism of suppressing bubble shielding effect. There is a 2.6-fold increase in stone fragmentation efficiency after 1000 SWs at PRF of 1 Hz in combination with LIPUS. In summary, combination of SWs and LIPUS is an effective way of suppressing bubble shielding effect and, subsequently, improving cavitation at the focus for a better outcome. Copyright © 2014 Elsevier B.V. All rights reserved.

Germline cytotoxic lymphocytes defective mutations in Chinese patients with lymphoma.

PubMed

Chen, Xue; Zhang, Yang; Wang, Fang; Wang, Mangju; Teng, Wen; Lin, Yuehui; Han, Xiangping; Jin, Fangyuan; Xu, Yuanli; Cao, Panxiang; Fang, Jiancheng; Zhu, Ping; Tong, Chunrong; Liu, Hongxing

2017-11-01

Certain patients with lymphoma may harbor mutations in perforin 1 (PRF1), unc-13 homolog D (UNC13D), syntaxin 11 (STX11), STXBP2 (syntaxin binding protein 2) or SH2 domain containing 1A (SH2D1A), which causes functional defects of cytotoxic lymphocytes. Data regarding the association between genetic defects and the development of lymphoma in Chinese patients are limited to date. In the present study, 90 patients with lymphoma were analyzed for UNC13D, PRF1, STXBP2, STX11, SH2D1A and X-linked inhibitor of apoptosis. Mutations were observed in 24 (26.67%) patients; 16 patients exhibited mutations in UNC13D, 7 exhibited PRF1 mutations, and 1 exhibited monoallelic mutation in STX11. UNC13D c.2588G>A/p.G863D mutation was detected in 9 patients (10.00%) and in 4/210 controls (1.90%). This mutation was predicted to be pathogenic and it predominantly existed in the Chinese population. These findings suggest that impaired cytotoxic machinery may represent a predisposing factor for the development of lymphoma. Furthermore, these data describe a distinct mutation spectrum in Chinese patients with lymphoma, whereby UNC13D is the most frequently mutated gene. In addition, these findings suggest UNC13D c.2588G>A mutation is a founder mutation in Chinese patients.

Germline cytotoxic lymphocytes defective mutations in Chinese patients with lymphoma

PubMed Central

Chen, Xue; Zhang, Yang; Wang, Fang; Wang, Mangju; Teng, Wen; Lin, Yuehui; Han, Xiangping; Jin, Fangyuan; Xu, Yuanli; Cao, Panxiang; Fang, Jiancheng; Zhu, Ping; Tong, Chunrong; Liu, Hongxing

2017-01-01

Certain patients with lymphoma may harbor mutations in perforin 1 (PRF1), unc-13 homolog D (UNC13D), syntaxin 11 (STX11), STXBP2 (syntaxin binding protein 2) or SH2 domain containing 1A (SH2D1A), which causes functional defects of cytotoxic lymphocytes. Data regarding the association between genetic defects and the development of lymphoma in Chinese patients are limited to date. In the present study, 90 patients with lymphoma were analyzed for UNC13D, PRF1, STXBP2, STX11, SH2D1A and X-linked inhibitor of apoptosis. Mutations were observed in 24 (26.67%) patients; 16 patients exhibited mutations in UNC13D, 7 exhibited PRF1 mutations, and 1 exhibited monoallelic mutation in STX11. UNC13D c.2588G>A/p.G863D mutation was detected in 9 patients (10.00%) and in 4/210 controls (1.90%). This mutation was predicted to be pathogenic and it predominantly existed in the Chinese population. These findings suggest that impaired cytotoxic machinery may represent a predisposing factor for the development of lymphoma. Furthermore, these data describe a distinct mutation spectrum in Chinese patients with lymphoma, whereby UNC13D is the most frequently mutated gene. In addition, these findings suggest UNC13D c.2588G>A mutation is a founder mutation in Chinese patients. PMID:29113160

Chemical and microstructural characterizations of plasma polymer films by time-of-flight secondary ion mass spectrometry and principal component analysis

NASA Astrophysics Data System (ADS)

Cossement, Damien; Renaux, Fabian; Thiry, Damien; Ligot, Sylvie; Francq, Rémy; Snyders, Rony

2015-11-01

It is accepted that the macroscopic properties of functional plasma polymer films (PPF) are defined by their functional density and their crosslinking degree (χ) which are quantities that most of the time behave in opposite trends. If the PPF chemistry is relatively easy to evaluate, it is much more challenging for χ. This paper reviews the recent work developed in our group on the application of principal component analysis (PCA) to time-of-flight secondary ion mass spectrometric (ToF-SIMS) positive spectra data in order to extract the relative cross-linking degree (χ) of PPF. NH2-, COOR- and SH-containing PPF synthesized in our group by plasma enhanced chemical vapor deposition (PECVD) varying the applied radiofrequency power (PRF), have been used as model surfaces. For the three plasma polymer families, the scores of the first computed principal component (PC1) highlighted significant differences in the chemical composition supported by X-Ray photoelectron spectroscopy (XPS) data. The most important fragments contributing to PC1 (loadings > 90%) were used to compute an average C/H ratio index for samples synthesized at low and high PRF. This ratio being an evaluation of χ, these data, accordingly to the literature, indicates an increase of χ with PRF excepted for the SH-PPF. These results have been cross-checked by the evaluation of functional properties of the plasma polymers namely a linear correlation with the stability of NH2-PPF in ethanol and a correlation with the mechanical properties of the COOR-PPF. For the SH-PPF family, the peculiar evolution of χ is supported by the understanding of the growth mechanism of the PPF from plasma diagnostic. The whole set of data clearly demonstrates the potential of the PCA method for extracting information on the microstructure of plasma polymers from ToF-SIMS measurements.

Second-generation Platelet Concentrate (Platelet-rich Fibrin) as a Scaffold in Regenerative Endodontics: A Case Series.

PubMed

Bakhtiar, Hengameh; Esmaeili, Shahram; Fakhr Tabatabayi, Setareh; Ellini, Mohammad Reza; Nekoofar, Mohammad Hossein; Dummer, Paul M H

2017-03-01

The purpose of this case series was to report the clinical and radiographic results of a pulp regenerative procedure using platelet-rich fibrin (PRF), a second-generation platelet concentrate, in immature teeth with necrotic pulps. Root canal revascularization using PRF was performed on 4 immature teeth with necrotic pulps. After access cavity preparation, the root canals were irrigated with low concentration sodium hypochlorite solution (1.5% sodium hypochlorite [20 mL/canal, 5 minutes]) and then irrigated with saline (20 mL/canal, 5 minutes). Equal proportions (167 mg) of ciprofloxacin, metronidazole, and cefaclor were mixed and diluted to a final concentration of 1 g/mL. Finally, the canal was sealed with 3-4 mm of a temporary restorative material, and patients were dismissed for 2 to 3 weeks. At the second appointment, 9 mL of the patient's whole blood was obtained and centrifuged to prepare a PRF clot. Canals were irrigated with 17% EDTA, and a sharp spreader was inserted beyond the apex. Then, the PRF clot was placed inside the root canals, and Biodentine (Septodont, Saint-Maur, France) was placed directly over the PRF. The teeth were restored permanently with glass ionomer cement and composite resin. Clinical examinations revealed that all cases were asymptomatic at the recall appointments at 1, 3, 6, 12, and 18 months. Radiographs revealed resolution of the periapical lesions, further root development, and apical closure in all cases. On the basis of the short-term results up to 12 months, PRF clots acted as successful scaffolds for the regeneration of pulpal contents in immature teeth with necrotic pulps. Copyright © 2016 American Association of Endodontists. All rights reserved.

Power Doppler signal calibration between ultrasound machines by use of a capillary-flow phantom for pannus vascularity in rheumatoid finger joints: a basic study.

PubMed

Sakano, Ryosuke; Kamishima, Tamotsu; Nishida, Mutsumi; Horie, Tatsunori

2015-01-01

Ultrasound allows the detection and grading of inflammation in rheumatology. Despite these advantages of ultrasound in the management of rheumatoid patients, it is well known that there are significant machine-to-machine disagreements regarding signal quantification. In this study, we tried to calibrate the power Doppler (PD) signal of two models of ultrasound machines by using a capillary-flow phantom. After flow velocity analysis in the perfusion cartridge at various injection rates (0.1-0.5 ml/s), we measured the signal count in the perfusion cartridge at various injection rates and pulse repetition frequencies (PRFs) by using PD, perfusing an ultrasound micro-bubble contrast agent diluted with normal saline simulating human blood. By use of the data from two models of ultrasound machines, Aplio 500 (Toshiba) and Avius (Hitachi Aloka), the quantitative PD (QPD) index [the summation of the colored pixels in a 1 cm × 1 cm rectangular region of interest (ROI)] was calculated via Image J (internet free software). We found a positive correlation between the injection rate and the flow velocity. In Aplio 500 and Avius, we found negative correlations between the PRF and the QPD index when the flow velocity was constant, and a positive correlation between flow velocity and the QPD index at constant PRF. The equation for the relationship of the PRF between Aplio 500 and Avius was: y = 0.023x + 0.36 [y = PRF of Avius (kHz), x = PRF of Aplio 500 (kHz)]. Our results suggested that the signal calibration of various models of ultrasound machines is possible by adjustment of the PRF setting.

Effects of Plasma Rich in Growth Factors and Platelet-Rich Fibrin on Proliferation and Viability of Human Gingival Fibroblasts

PubMed Central

Vahabi, Surena; Vaziri, Shahram; Torshabi, Maryam

2015-01-01

Objectives: Platelet preparations are commonly used to enhance bone and soft tissue regeneration. Considering the existing controversies on the efficacy of platelet products for tissue regeneration, more in vitro studies are required. The aim of the present study was to compare the in vitro effects of plasma rich in growth factors (PRGF) and platelet-rich fibrin (PRF) on proliferation and viability of human gingival fibroblasts (HGFs). Materials and Methods: Anitua’s PRGF and Choukran’s PRF were prepared according to the standard protocols. After culture periods of 24, 48 and 72 hours, proliferation of HGFs was evaluated by the methyl thiazol tetrazolium assay. Statistical analysis was performed using one-way ANOVA followed by Tukey-Kramer’s multiple comparisons and P-values<0.05 were considered statistically significant. Results: PRGF treatment induced statistically significant (P<0.001) proliferation of HGF cells compared to the negative control (100% viability) at 24, 48 and 72 hours in values of 123%±2.25%, 102%±2.8% and 101%±3.92%, respectively. The PRF membrane treatment of HGF cells had a statistically significant effect on cell proliferation (21%±1.73%, P<0.001) at 24 hours compared to the negative control. However, at 48 and 72 hours after treatment, PRF had a negative effect on HGF cell proliferation and caused 38% and 60% decrease in viability and proliferation compared to the negative control, respectively. The HGF cell proliferation was significantly higher in PRGF than in PRF group (P< 0.001). Conclusion: This study demonstrated that PRGF had a strong stimulatory effect on HGF cell viability and proliferation compared to PRF. PMID:26877740

Effect of centrifugation time on growth factor and MMP release of an experimental platelet-rich fibrin-type product.

PubMed

Eren, Gülnihal; Gürkan, Ali; Atmaca, Harika; Dönmez, Ayhan; Atilla, Gül

2016-07-01

Platelet-rich fibrin (PRF) has a controlled release of growth factors due to the fibrin matrix structure. Different centrifugation protocols were suggested for PRF preparation. Since the derivation method of PRF can alter its contents, in the present study it is aimed to investigate the cell contents and transforming growth factor beta-1 (TGF-β1), platelet-derived growth factor (PDGF-AB), vascular endothelial growth factor (VEGF), matrix metalloproteinase (MMP)-1 and-8 release from experimental PRF-type membranes obtained with different centrifugation times at 400 gravity. Three blood samples were collected from 20 healthy non-smoker volunteers. One tube was used for whole blood analyses. The other two tubes were centrifuged at 400 g for 10 minutes (group A) or 12 minutes (group B). Each experimental PRF-type membrane was placed in Dulbecco's Modified Eagle's Medium (DMEM)and at 1, 24 and 72 hours, TGF-β1, PDGF-AB, VEGF, MMP-1 and -8 release amounts were analysed by enzyme-linked immunosorbent assay (ELISA). The blood cell count of membranes was determined by subtracting plasma supernatant and red blood cell (RBC) mixture from the whole blood cell counts. At 72 hours, the VEGF level of group B was statistically higher than that of group A (p = 0.040). The centrifugation time was not found to influence the release of other growth factors, enzymes and cell counts. Within the limits of the present study, it might be suggested that centrifugation time at a constant gravity has a significant effect on the VEGF levels released from experimental PRF-type membrane. It can be concluded that due to the importance of VEGF in the tissue healing process, membranes obtained at 12-minute centrifugation time may show a superior potential in wound healing.

Pulsed Radiofrequency as a Minimally Invasive Treatment Option in Anterior Cutaneous Nerve Entrapment Syndrome: A Retrospective Analysis of 26 Patients

PubMed Central

Maatman, Robbert C.; Steegers, Monique A.H.; Kallewaard, Jan-Willem; Scheltinga, Marc R.M.; Roumen, Rudi M.H.

2018-01-01

Background Chronic abdominal pain is occasionally due to entrapped intercostal nerve endings (ACNES, abdominal cutaneous nerve entrapment syndrome). If abdominal wall infiltration using an anesthetic agent is unsuccessful, a neurectomy may be considered. Pulsed radiofrequency (PRF) is a relatively new treatment option for various chronic pain syndromes. Evidence regarding a beneficial effect of this minimally invasive technique in ACNES is lacking. The aim was to assess the effectiveness of PRF treatment in ACNES patients. Methods A series of ACNES patients undergoing PRF treatment between January 2014 and December 2015 in two hospitals were retrospectively evaluated. Pain was recorded prior to treatment and after 6 weeks using a numerical rating scale (NRS, 0 (no pain) to 10 (worst possible pain)). Successful treatment was defined as > 50% NRS pain reduction. Patient satisfaction was scored by patient global impression of change (PGIC, 1 = very much worse, to 7 = very much improved). Results Twenty-six patients were studied (17 women, median age 47 years, range 18 - 67 years). After 6 weeks, mean NRS score had dropped from 6.7 ± 1.2 to 3.8 ± 2.3 (P < 0.001). A mean 4.9 ± 1.4 PGIC score was reported by then. Short term treatment success (6 - 8 weeks) was 50% (n = 13, 95% CI: 29 - 71), while 8% was pain-free on the longer term (median 15 months). Median effect duration was 4 months (range 2 - 26). Conclusions PRF is temporarily effective in half of patients with ACNES. PRF is safe and may be favored in neuropathic pain syndromes as nerve tissue destruction is possibly limited. A randomized controlled trial determining the potential additional role of PRF in the treatment strategy for ACNES is underway. PMID:29707093

Randomized, double-blind, comparative-effectiveness study comparing pulsed radiofrequency to steroid injections for occipital neuralgia or migraine with occipital nerve tenderness.

PubMed

Cohen, Steven P; Peterlin, B Lee; Fulton, Larry; Neely, Edward T; Kurihara, Connie; Gupta, Anita; Mali, Jimmy; Fu, Diana C; Jacobs, Michael B; Plunkett, Anthony R; Verdun, Aubrey J; Stojanovic, Milan P; Hanling, Steven; Constantinescu, Octav; White, Ronald L; McLean, Brian C; Pasquina, Paul F; Zhao, Zirong

2015-12-01

Occipital neuralgia (ON) is characterized by lancinating pain and tenderness overlying the occipital nerves. Both steroid injections and pulsed radiofrequency (PRF) are used to treat ON, but few clinical trials have evaluated efficacy, and no study has compared treatments. We performed a multicenter, randomized, double-blind, comparative-effectiveness study in 81 participants with ON or migraine with occipital nerve tenderness whose aim was to determine which treatment is superior. Forty-two participants were randomized to receive local anesthetic and saline, and three 120 second cycles of PRF per targeted nerve, and 39 were randomized to receive local anesthetic mixed with deposteroid and 3 rounds of sham PRF. Patients, treating physicians, and evaluators were blinded to interventions. The PRF group experienced a greater reduction in the primary outcome measure, average occipital pain at 6 weeks (mean change from baseline -2.743 ± 2.487 vs -1.377 ± 1.970; P < 0.001), than the steroid group, which persisted through the 6-month follow-up. Comparable benefits favoring PRF were obtained for worst occipital pain through 3 months (mean change from baseline -1.925 ± 3.204 vs -0.541 ± 2.644; P = 0.043), and average overall headache pain through 6 weeks (mean change from baseline -2.738 ± 2.753 vs -1.120 ± 2.1; P = 0.037). Adverse events were similar between groups, and few significant differences were noted for nonpain outcomes. We conclude that although PRF can provide greater pain relief for ON and migraine with occipital nerve tenderness than steroid injections, the superior analgesia may not be accompanied by comparable improvement on other outcome measures.

Randomized, double-blind, comparative-effectiveness study comparing pulsed radiofrequency to steroid injections for occipital neuralgia or migraine with occipital nerve tenderness

PubMed Central

Cohen, Steven P.; Peterlin, B. Lee; Fulton, Larry; Neely, Edward T.; Kurihara, Connie; Gupta, Anita; Mali, Jimmy; Fu, Diana C.; Jacobs, Michael B.; Plunkett, Anthony R.; Verdun, Aubrey J.; Stojanovic, Milan P.; Hanling, Steven; Constantinescu, Octav; White, Ronald L.; McLean, Brian C.; Pasquina, Paul F.; Zhao, Zirong

2015-01-01

Occipital neuralgia (ON) is characterized by lancinating pain and tenderness overlying the occipital nerves. Both steroid injections and pulsed radiofrequency (PRF) are used to treat ON, but few clinical trials have evaluated efficacy, and no study has compared treatments. We performed a multicenter, randomized, double-blind, comparative-effectiveness study in 81 participants with ON or migraine with occipital nerve tenderness whose aim was to determine which treatment is superior. Forty-two participants were randomized to receive local anesthetic and saline, and three 120 second cycles of PRF per targeted nerve, and 39 were randomized to receive local anesthetic mixed with deposteroid and 3 rounds of sham PRF. Patients, treating physicians, and evaluators were blinded to interventions. The PRF group experienced a greater reduction in the primary outcome measure, average occipital pain at 6 weeks (mean change from baseline −2.743 ± 2.487 vs −1.377 ± 1.970; P <0.001), than the steroid group, which persisted through the 6-month follow-up. Comparable benefits favoring PRF were obtained for worst occipital pain through 3 months (mean change from baseline−1.925 ± 3.204 vs−0.541 ± 2.644; P = 0.043), and average overall headache pain through 6 weeks (mean change from baseline −2.738 ± 2.753 vs −1.120 ± 2.1; P = 0.037). Adverse events were similar between groups, and few significant differences were noted for nonpain outcomes. We conclude that although PRF can provide greater pain relief for ON and migraine with occipital nerve tenderness than steroid injections, the superior analgesia may not be accompanied by comparable improvement on other outcome measures. PMID:26447705

Multiple Gingival Recession Coverage Treated with Vestibular Incision Subperiosteal Tunnel Access Approach with or without Platelet-Rich Fibrin - A Case Series

PubMed Central

Garg, Surbhi; Arora, Sachit Anand; Chhina, Shivjot; Singh, Padam

2017-01-01

Background: Gingival recession involves both soft tissue and hard tissue loss. In this evolutionary era of dentistry, newer techniques have evolved for complete coverage of isolated recession defects. Since 2012, vestibular incision subperiosteal tunnel access (VISTA) technique was used with various regenerative membranes to treat multiple recession defects (MRDs). Platelet-rich fibrin (PRF) membrane, a pool of growth factors but have any added advantage to recession coverage techniques is controversial. Thus, in this case series, we compare the effect of VISTA with or without PRF-membrane for the treatment of Classes I and III MRDs. Subjects and Methods: Four patients between of age 30 and 40 years (two patients having bilateral Class I and another two having bilateral Class III MRDs) were selected from the Department of Periodontics, ITS Dental College, Greater Noida and designated as Case I–IV simultaneously. Recession defects at antagonist sites in each patient were corrected by VISTA approach with or without PRF-membrane. Recorded clinical parameters included recession depth, recession width, pocket probing depth, and clinical attachment level (CAL) at baseline and 6 months postoperatively. Results: Patients having Class I recession defects showed almost complete root coverage with VISTA technique alone and reflected no added advantage of PRF-membrane. However, patients with Class III recession defects treated with VISTA + PRF-membrane showed more reduction in recession depth and gain in CAL as compared to sites treated with VISTA only. Conclusion: VISTA alone is a convenient technique for treatment of Class I MRDs. Addition of PRF-membrane for Class III recession defects give better outcome in term of reduction of recession depth and gain in CAL 6 month postoperatively. PMID:29042736

Improving Photometry and Stellar Signal Preservation with Pixel-Level Systematic Error Correction

NASA Technical Reports Server (NTRS)

Kolodzijczak, Jeffrey J.; Smith, Jeffrey C.; Jenkins, Jon M.

2013-01-01

The Kepler Mission has demonstrated that excellent stellar photometric performance can be achieved using apertures constructed from optimally selected CCD pixels. The clever methods used to correct for systematic errors, while very successful, still have some limitations in their ability to extract long-term trends in stellar flux. They also leave poorly correlated bias sources, such as drifting moiré pattern, uncorrected. We will illustrate several approaches where applying systematic error correction algorithms to the pixel time series, rather than the co-added raw flux time series, provide significant advantages. Examples include, spatially localized determination of time varying moiré pattern biases, greater sensitivity to radiation-induced pixel sensitivity drops (SPSDs), improved precision of co-trending basis vectors (CBV), and a means of distinguishing the stellar variability from co-trending terms even when they are correlated. For the last item, the approach enables physical interpretation of appropriately scaled coefficients derived in the fit of pixel time series to the CBV as linear combinations of various spatial derivatives of the pixel response function (PRF). We demonstrate that the residuals of a fit of soderived pixel coefficients to various PRF-related components can be deterministically interpreted in terms of physically meaningful quantities, such as the component of the stellar flux time series which is correlated with the CBV, as well as, relative pixel gain, proper motion and parallax. The approach also enables us to parameterize and assess the limiting factors in the uncertainties in these quantities.

Design and development of data acquisition system for the Louisiana accelerated loading device : final report.

DOT National Transportation Integrated Search

1992-09-01

The Louisiana Transportation Research Center has established a Pavement Research Facility (PRF). The core of the PRF is a testing machine that is capable of conducting full-scale simulated and accelerated load testing of pavement materials, construct...

Studies by immune electron microscopy of hepatitis B surface antigen in PLC/PRF/5 cells.

PubMed

Shibayama, T; Watanabe, T; Kojima, H; Yoshikawa, A; Watanabe, S; Kamimura, T; Suzuki, S; Ichida, F

1984-01-01

Electron microscopic studies of the morphology of hepatitis B surface antigen (HBsAg) produced by PLC/PRF/5 cells in vitro were carried out. Aggregates of 20-nm spherical particles in 3-day culture supernatants were observed by immune electron microscopy (IEM). Aggregates of tubular structures were found with IEM in the extracts of the cells. Tubular structures 18 to 22 nm in diameter were seen by electron microscopy (EM) in the cisternae of the endoplasmic reticulum in 2-3% of the cells. The tubular structures in the cytoplasm and extracts of PLC/PRF/5 cells resembled those observed in the hepatocytes of human carriers of hepatitis B virus (HBV). Intracellular localization of HBsAg in PLC/PRF/5 cells by direct peroxidase-conjugated antibody staining was observed on the tubular structures and the cisternal wall, which contained these structures. Rotation technique analysis indicated that the tubular structures were composed of 11 or 12 subunits.

Correction of Dual-PRF Doppler Velocity Outliers in the Presence of Aliasing

DOE Office of Scientific and Technical Information (OSTI.GOV)

Altube, Patricia; Bech, Joan; Argemí, Oriol

In Doppler weather radars, the presence of unfolding errors or outliers is a well-known quality issue for radial velocity fields estimated using the dual–pulse repetition frequency (PRF) technique. Postprocessing methods have been developed to correct dual-PRF outliers, but these need prior application of a dealiasing algorithm for an adequate correction. Our paper presents an alternative procedure based on circular statistics that corrects dual-PRF errors in the presence of extended Nyquist aliasing. The correction potential of the proposed method is quantitatively tested by means of velocity field simulations and is exemplified in the application to real cases, including severe storm events.more » The comparison with two other existing correction methods indicates an improved performance in the correction of clustered outliers. The technique we propose is well suited for real-time applications requiring high-quality Doppler radar velocity fields, such as wind shear and mesocyclone detection algorithms, or assimilation in numerical weather prediction models.« less

Antimicrobial effect of platelet-rich plasma and platelet-rich fibrin.

PubMed

Badade, Pallavi S; Mahale, Swapna A; Panjwani, Alisha A; Vaidya, Prutha D; Warang, Ayushya D

2016-01-01

Platelet concentrates have been extensively used in a variety of medical fields to promote soft- and hard-tissue regeneration. The significance behind their use lies in the abundance of growth factors (GFs) in platelets α-granules that promote wound healing. Other than releasing a pool of GFs upon activation, platelets also have many features that indicate their role in the anti-infective host defense. The aim of this study is to evaluate the antimicrobial activities of platelet-rich plasma (PRP) and platelet-rich fibrin (PRF) against periodontal disease-associated bacteria. Blood samples were obtained from ten adult male patients. PRP and PRF were procured using centrifugation. The antimicrobial activity of PRP and PRF was evaluated by microbial culturing using bacterial strains of Porphyromonas gingivalis and Aggregatibacter actinomycetemcomitans. P. gingivalis and A. actinomycetemcomitans were inhibited by PRP but not by PRF. PRP is a potentially useful substance in the fight against periodontal pathogens. This might represent a valuable property in adjunct to the enhancement of tissue regeneration.

High frequency electroporation efficiency is under control of membrane capacitive charging and voltage potential relaxation.

PubMed

Novickij, Vitalij; Ruzgys, Paulius; Grainys, Audrius; Šatkauskas, Saulius

2018-02-01

The study presents the proof of concept for a possibility to achieve a better electroporation in the MHz pulse repetition frequency (PRF) region compared to the conventional low frequency protocols. The 200ns×10 pulses bursts of 10-14kV/cm have been used to permeabilize Chinese hamster ovary (CHO) cells in a wide range (1Hz-1MHz) of PRF. The permeabilization efficiency was evaluated using fluorescent dye assay (propidium iodide) and flow cytometry. It was determined that a threshold PRF exists when the relaxation of the cell transmembrane potential is longer than the delay between the consequent pulses, which results in accumulation of the charge on the membrane. For the CHO cells and 0.1S/m electroporation medium, this phenomenon is detectable in the 0.5-1MHz range. It was shown that the PRF is an important parameter that could be used for flexible control of electroporation efficiency in the high frequency range. Copyright © 2017 Elsevier B.V. All rights reserved.

Correction of Dual-PRF Doppler Velocity Outliers in the Presence of Aliasing

DOE PAGES

Altube, Patricia; Bech, Joan; Argemí, Oriol; ...

2017-07-18

In Doppler weather radars, the presence of unfolding errors or outliers is a well-known quality issue for radial velocity fields estimated using the dual–pulse repetition frequency (PRF) technique. Postprocessing methods have been developed to correct dual-PRF outliers, but these need prior application of a dealiasing algorithm for an adequate correction. Our paper presents an alternative procedure based on circular statistics that corrects dual-PRF errors in the presence of extended Nyquist aliasing. The correction potential of the proposed method is quantitatively tested by means of velocity field simulations and is exemplified in the application to real cases, including severe storm events.more » The comparison with two other existing correction methods indicates an improved performance in the correction of clustered outliers. The technique we propose is well suited for real-time applications requiring high-quality Doppler radar velocity fields, such as wind shear and mesocyclone detection algorithms, or assimilation in numerical weather prediction models.« less

Effect of pulse duration and pulse repetition frequency of cavitation histotripsy on erosion at the surface of soft material.

PubMed

Zhou, Yufeng; Wang, Xiaotong

2018-03-01

Cavitation histotripsy with the short pulse duration (PD) but high pulse repetition frequency (PRF) disintegrates the tissue at a fluid interface. However, longer PD and lower PRF are used in the other focused ultrasound applications, where the acoustic radiation force, streaming, and cavitation are different, and their effects on erosion are unknown. In this study, the erosion at the surface of phantom/ex vivo tissue and the characteristics of induced bubble cloud captured by high-speed photography, passive cavitation detection, and light transmission during histotripsy exposure at varied PDs and PRFs but the same duty cycle were compared. The peak negative pressure of 6.6 MPa at the PD of 20 ms and PRF of 1 Hz began to erode the phantom, which becomes more significant with the increase of peak negative pressure, PD, and interval time between bursts. The increase of the PRF from 1 Hz to 1000 Hz, while the decrease of the PD from 20 ms to 20 μs (duty cycle of 2%) at the same energy was delivered to the gel phantom immersed in the degassed water led to the decrease of erosion volume but a slight increase of the erosion area and smoother surface. Low PRF and long PD produce the significant tissue deformation, acoustic wave refocusing, confinement of bubbles in a conical region, and more bubble dissolution after the collapse for the high acoustic scattering and light transmission signals. In comparison, high PRF and low PD produce a wide distribution of bubbles with only little wave refocusing at the beginning of cavitation histotripsy and high inertial cavitation. Acoustic emission dose has a good correlation with the erosion volume. The erosion on the porcine kidney at the varied PRFs and PDs with the same energy output showed similar trends as those in the phantom but at a slow rate. In summary, the PRF and PD are important parameters for the cavitation histotripsy-induced erosion at the interface of fluid and soft material, and they should be optimized for the best outcome. Copyright © 2017 Elsevier B.V. All rights reserved.

Platelet-rich fibrin application in dentistry: a literature review.

PubMed

Borie, Eduardo; Oliví, Daniel García; Orsi, Iara Augusta; Garlet, Katia; Weber, Benjamín; Beltrán, Víctor; Fuentes, Ramón

2015-01-01

The development of bioactive surgical additives to regulate the inflammation and increase the speed of healing process is one of the great challenges in clinical research. In this sense, platelet rich fibrin (PRF) appears as a natural and satisfactory alternative with favorable results and low risks. The following review attempts to summarize the relevant literature regarding the technique of using PRF, focusing on its preparation, advantages, and disadvantages of using it in clinical applications. PRF alone or in combination with other biomaterials seems to have several advantages and indications both for medicine and dentistry, due it is a minimally invasive technique with low risks and satisfactory clinical results.

Implementation Issues for Cr6+ Free M&P

DTIC Science & Technology

2008-02-27

85582 Performance Range, with Topcoat MIL-PRF-23377 & MIL-PRF-85582 Performance Range, no Topcoat NCAP Data Assessment • Project originally designed to...documented and distributed as part of ESTCP NCAP project report • Initial assessment suggests that a standard practice to assess coating systems can be

Exogenous hydrogen sulfide promotes hepatocellular carcinoma cell growth by activating the STAT3-COX-2 signaling pathway

PubMed Central

Zhen, Yulan; Wu, Qiaomei; Ding, Yiqian; Zhang, Wei; Zhai, Yuansheng; Lin, Xiaoxiong; Weng, Yunxia; Guo, Ruixian; Zhang, Ying; Feng, Jianqiang; Lei, Yiyan; Chen, Jingfu

2018-01-01

The effects of hydrogen sulfide (H2S) on cancer are controversial. Our group previously demonstrated that exogenous H2S promotes the development of cancer via amplifying the activation of the nuclear factor-κB signaling pathway in hepatocellular carcinoma (HCC) cells (PLC/PRF/5). The present study aimed to further investigate the hypothesis that exogenous H2S promotes PLC/PRF/5 cell proliferation and migration, and inhibits apoptosis by activating the signal transducer and activator of transcription 3 (STAT3)-cyclooxygenase-2 (COX-2) signaling pathway. PLC/PRF/5 cells were treated with 500 µmol/l NaHS (a donor of H2S) for 24 h. The expression levels of phosphorylated (p)-STAT3, STAT3, cleaved caspase-3 and COX-2 were measured by western blot assay. Cell viability was detected by Cell Counting kit-8 assay. Apoptotic cells were observed by Hoechst 33258 staining. The expression of STAT3 and COX-2 messenger RNA (mRNA) was detected by semiquantitative reverse transcription-polymerase chain reaction. The production of vascular endothelial growth factor (VEGF) was evaluated by ELISA. The results indicated that treatment of PLC/PRF/5 cells with 500 µmol/l NaHS for 24 h markedly increased the expression levels of p-STAT3 and STAT3 mRNA, leading to COX-2 and COX-2 mRNA overexpression, VEGF induction, decreased cleaved caspase-3 production, increased cell viability and migration, and decreased number of apoptotic cells. However, co-treatment of PLC/PRF/5 cells with 500 µmol/l NaHS and 30 µmol/l AG490 (an inhibitor of STAT3) or 20 µmol/l NS-398 (an inhibitor of COX-2) for 24 h significantly reverted the effects induced by NaHS. Furthermore, co-treatment of PLC/PRF/5 cells with 500 µmol/l NaHS and 30 µmol/l AG490 markedly decreased the NaHS-induced increase in the expression level of COX-2. By contrast, co-treatment of PLC/PRF/5 cells with 500 µmol/l NaHS and 20 µmol/l NS-398 inhibited the NaHS-induced increase in the expression level of p-STAT3. In conclusion, the findings of the present study provide evidence that the STAT3-COX-2 signaling pathway is involved in NaHS-induced cell proliferation, migration, angiogenesis and anti-apoptosis in PLC/PRF/5 cells, and suggest that the positive feedback between STAT3 and COX-2 may serve a crucial role in hepatocellular carcinoma carcinogenesis. PMID:29725404

HD-03/ES: A Herbal Medicine Inhibits Hepatitis B Surface Antigen Secretion in Transfected Human Hepatocarcinoma PLC/PRF/5 Cells.

PubMed

Varma, Sandeep R; Sundaram, R; Gopumadhavan, S; Vidyashankar, Satyakumar; Patki, Pralhad S

2013-01-01

HD-03/ES is a herbal formulation used for the treatment of hepatitis B. However, the molecular mechanism involved in the antihepatitis B (HBV) activity of this drug has not been studied using in vitro models. The effect of HD-03/ES on hepatitis B surface antigen (HBsAg) secretion and its gene expression was studied in transfected human hepatocarcinoma PLC/PRF/5 cells. The anti-HBV activity was tested based on the inhibition of HBsAg secretion into the culture media, as detected by HBsAg-specific antibody-mediated enzyme assay (ELISA) at concentrations ranging from 125 to 1000  μ g/mL. The effect of HD-03/ES on HBsAg gene expression was analyzed using semiquantitative multiplex RT-PCR by employing specific primers. The results showed that HD-03/ES suppressed HBsAg production with an IC50 of 380  μ g/mL in PLC/PRF/5 cells for a period of 24 h. HD-03/ES downregulated HBsAg gene expression in PLC/PRF/5 cells. In conclusion, HD-03/ES exhibits strong anti-HBV properties by inhibiting the secretion of hepatitis B surface antigen in PLC/PRF/5 cells, and this action is targeted at the transcription level. Thus, HD-03/ES could be beneficial in the treatment of acute and chronic hepatitis B infections.

Nano-biphasic calcium phosphate/polyvinyl alcohol composites with enhanced bioactivity for bone repair via low-temperature three-dimensional printing and loading with platelet-rich fibrin

PubMed Central

Wang, Chunmei; Zhang, Shuaishuai; Li, Donglin; Wang, Jimeng; Cao, Tianqing; Bi, Long; Pei, Guoxian

2018-01-01

Background and aim As a newly emerging three-dimensional (3D) printing technology, low-temperature robocasting can be used to fabricate geometrically complex ceramic scaffolds at low temperatures. Here, we aimed to fabricate 3D printed ceramic scaffolds composed of nano-biphasic calcium phosphate (BCP), polyvinyl alcohol (PVA), and platelet-rich fibrin (PRF) at a low temperature without the addition of toxic chemicals. Methods Corresponding nonprinted scaffolds were prepared using a freeze-drying method. Compared with the nonprinted scaffolds, the printed scaffolds had specific shapes and well-connected internal structures. Results The incorporation of PRF enabled both the sustained release of bioactive factors from the scaffolds and improved biocompatibility and biological activity toward bone marrow-derived mesenchymal stem cells (BMSCs) in vitro. Additionally, the printed BCP/PVA/PRF scaffolds promoted significantly better BMSC adhesion, proliferation, and osteogenic differentiation in vitro than the printed BCP/PVA scaffolds. In vivo, the printed BCP/PVA/PRF scaffolds induced a greater extent of appropriate bone formation than the printed BCP/PVA scaffolds and nonprinted scaffolds in a critical-size segmental bone defect model in rabbits. Conclusion These experiments indicate that low-temperature robocasting could potentially be used to fabricate 3D printed BCP/PVA/PRF scaffolds with desired shapes and internal structures and incorporated bioactive factors to enhance the repair of segmental bone defects. PMID:29416332

Comparison of the Mechanical Properties of Early Leukocyte- and Platelet-Rich Fibrin versus PRGF/Endoret Membranes.

PubMed

Khorshidi, Hooman; Raoofi, Saeed; Bagheri, Rafat; Banihashemi, Hodasadat

2016-01-01

Objectives. The mechanical properties of membranes are important factors in the success of treatment and clinical handling. The goal of this study was to compare the mechanical properties of early leukocyte- and platelet-rich fibrin (L-PRF) versus PRGF/Endoret membrane. Materials and Methods. In this experimental study, membranes were obtained from 10 healthy male volunteers. After obtaining 20 cc venous blood from each volunteer, 10 cc was used to prepare early L-PRF (group 1) and the rest was used to get a membrane by PRGF-Endoret system (group 2). Tensile loads were applied to specimens using universal testing machine. Tensile strength, stiffness, and toughness of the two groups of membranes were calculated and compared by paired t-test. Results. The mean tensile strength and toughness were higher in group 1 with a significant difference (P < 0.05). The mean stiffness in group 1 was also higher but not statistically significant (P > 0.05). Conclusions. The results showed that early L-PRF membranes had stronger mechanical properties than membranes produced by PRGF-Endoret system. Early L-PRF membranes might have easier clinical handling and could be a more proper scaffold in periodontal regenerative procedures. The real results of the current L-PRF should be in fact much higher than what is reported here.

Comparison of the Mechanical Properties of Early Leukocyte- and Platelet-Rich Fibrin versus PRGF/Endoret Membranes

PubMed Central

Khorshidi, Hooman; Raoofi, Saeed; Bagheri, Rafat; Banihashemi, Hodasadat

2016-01-01

Objectives. The mechanical properties of membranes are important factors in the success of treatment and clinical handling. The goal of this study was to compare the mechanical properties of early leukocyte- and platelet-rich fibrin (L-PRF) versus PRGF/Endoret membrane. Materials and Methods. In this experimental study, membranes were obtained from 10 healthy male volunteers. After obtaining 20 cc venous blood from each volunteer, 10 cc was used to prepare early L-PRF (group 1) and the rest was used to get a membrane by PRGF-Endoret system (group 2). Tensile loads were applied to specimens using universal testing machine. Tensile strength, stiffness, and toughness of the two groups of membranes were calculated and compared by paired t-test. Results. The mean tensile strength and toughness were higher in group 1 with a significant difference (P < 0.05). The mean stiffness in group 1 was also higher but not statistically significant (P > 0.05). Conclusions. The results showed that early L-PRF membranes had stronger mechanical properties than membranes produced by PRGF-Endoret system. Early L-PRF membranes might have easier clinical handling and could be a more proper scaffold in periodontal regenerative procedures. The real results of the current L-PRF should be in fact much higher than what is reported here. PMID:26880919

[Long-term effects of pulsed radiofrequency on the dorsal root ganglion and segmental nerve roots for lumbosacral radicular pain: a prospective controlled randomized trial with nerve root block].

PubMed

Fujii, Hiromi; Kosogabe, Yoshinori; Kajiki, Hideki

2012-08-01

Although pulsed radiofrequency (PRF) method for lumbosacral radicular pain (LSRP) is reportedly effective, there are no prospective controlled trials. We assessed the long-term efficacy of PRF of the dorsal root ganglion and nerve roots for LSRP as compared with nerve root block (RB). The study included 27 patients suffering from LSRP. The design of this study was randomized with a RB control. In the PRF group, the PRF current was applied for 120 seconds after RB. In the RB group, the patients received RB only. Visual analogue scale (VAS) was assessed immediately before, and immediately, 2 hours, 1 day, 1 week, 1 month, 3 months, 6 months, and 1 year after the procedure. P<0.05 was regarded as denoting statistical significance. In both groups, the VAS not only of short-term but also of long-term (6 months and 1 year after procedure) significantly decreased as compared with that before treatment (P<0.05). There were no significant differences of VAS between the two groups at the same time points. This study indicates that PRF adjacent to the dorsal root ganglion and nerve roots for LSRP has long-term effects. There were no significant differences of long-term effects between the two groups.

In search of a consensus terminology in the field of platelet concentrates for surgical use: platelet-rich plasma (PRP), platelet-rich fibrin (PRF), fibrin gel polymerization and leukocytes.

PubMed

Dohan Ehrenfest, David M; Bielecki, Tomasz; Mishra, Allan; Borzini, Piero; Inchingolo, Francesco; Sammartino, Gilberto; Rasmusson, Lars; Everts, Peter A

2012-06-01

In the field of platelet concentrates for surgical use, most products are termed Platelet-Rich Plasma (PRP). Unfortunately, this term is very general and incomplete, leading to many confusions in the scientific database. In this article, a panel of experts discusses this issue and proposes an accurate and simple terminology system for platelet concentrates for surgical use. Four main categories of products can be easily defined, depending on their leukocyte content and fibrin architecture: Pure Platelet-Rich Plasma (P-PRP), such as cell separator PRP, Vivostat PRF or Anitua's PRGF; Leukocyteand Platelet-Rich Plasma (L-PRP), such as Curasan, Regen, Plateltex, SmartPReP, PCCS, Magellan, Angel or GPS PRP; Pure Plaletet-Rich Fibrin (P-PRF), such as Fibrinet; and Leukocyte- and Platelet-Rich Fibrin (L-PRF), such as Choukroun's PRF. P-PRP and L-PRP refer to the unactivated liquid form of these products, their activated versions being respectively named P-PRP gels and L-PRP gels. The purpose of this search for a terminology consensus is to plead for a more serious characterization of these products. Researchers have to be aware of the complex nature of these living biomaterials, in order to avoid misunderstandings and erroneous conclusions. Understanding the biomaterials or believing in the magic of growth factors ? From this choice depends the future of the field.

Nano-biphasic calcium phosphate/polyvinyl alcohol composites with enhanced bioactivity for bone repair via low-temperature three-dimensional printing and loading with platelet-rich fibrin.

PubMed

Song, Yue; Lin, Kaifeng; He, Shu; Wang, Chunmei; Zhang, Shuaishuai; Li, Donglin; Wang, Jimeng; Cao, Tianqing; Bi, Long; Pei, Guoxian

2018-01-01

As a newly emerging three-dimensional (3D) printing technology, low-temperature robocasting can be used to fabricate geometrically complex ceramic scaffolds at low temperatures. Here, we aimed to fabricate 3D printed ceramic scaffolds composed of nano-biphasic calcium phosphate (BCP), polyvinyl alcohol (PVA), and platelet-rich fibrin (PRF) at a low temperature without the addition of toxic chemicals. Corresponding nonprinted scaffolds were prepared using a freeze-drying method. Compared with the nonprinted scaffolds, the printed scaffolds had specific shapes and well-connected internal structures. The incorporation of PRF enabled both the sustained release of bioactive factors from the scaffolds and improved biocompatibility and biological activity toward bone marrow-derived mesenchymal stem cells (BMSCs) in vitro. Additionally, the printed BCP/PVA/PRF scaffolds promoted significantly better BMSC adhesion, proliferation, and osteogenic differentiation in vitro than the printed BCP/PVA scaffolds. In vivo, the printed BCP/PVA/PRF scaffolds induced a greater extent of appropriate bone formation than the printed BCP/PVA scaffolds and nonprinted scaffolds in a critical-size segmental bone defect model in rabbits. These experiments indicate that low-temperature robocasting could potentially be used to fabricate 3D printed BCP/PVA/PRF scaffolds with desired shapes and internal structures and incorporated bioactive factors to enhance the repair of segmental bone defects.

Insulin-like growth factor-binding protein 7 alters the sensitivity to interferon-based anticancer therapy in hepatocellular carcinoma cells.

PubMed

Tomimaru, Y; Eguchi, H; Wada, H; Noda, T; Murakami, M; Kobayashi, S; Marubashi, S; Takeda, Y; Tanemura, M; Umeshita, K; Doki, Y; Mori, M; Nagano, H

2010-05-11

A striking efficiency of interferon (IFN)-based anticancer therapy for advanced hepatocellular carcinoma (HCC) has been reported. Because its clinical efficiency greatly depends on each patient's local response, prediction of local response is crucial. Continuous exposure of IFN-alpha to parental PLC/PRF/5 cells (PLC-P) and a limiting dilution method resulted in the establishment of IFN-resistant cell clones (PLC-Rs). Microarray analyses of PLC-P and PLC-Rs identified insulin-like growth factor-binding protein 7 (IGFBP7) as one of the most significantly downregulated genes in PLC-Rs. Changes in anticancer effects of IFN-alpha were examined in HCC cells after genetic manipulation of IGFBP7 expression. The correlation between immunohistochemically determined IGFBP7 expression and the response to IFN-alpha/5-fluorouracil (5-FU) therapy was investigated in surgically resected HCC specimens. PLC-R cells showed a remarkable downregulation of IGFBP7 and resistance to IFN-alpha, compared with PLC-P. Parental PLC/PRF/5 cells transfected with short hairpin RNA against IGFBP7 showed a significant resistance to IFN-alpha relative to control cells (IC(50) fold increase=14.38 times). Insulin-like growth factor-binding protein 7 transfection into PLC-R restored sensitivity to IFN-alpha. In resected specimens, IGFBP7 expression significantly correlated with the response to IFN-alpha/5-FU therapy. IGFBP7 could be a useful predictor of the response to IFN-based therapy in advanced HCC.

U.S. Air Force Aircrew Flight Protective Eyewear Program

DTIC Science & Technology

2013-02-01

MIL-DTL-32000), fire - resistant hydraulic fluid (MIL-PRF-46170), petroleum-based hydraulic fluid (MIL-PRF-6083), gasoline (87% octane), motor oil...UPLC installed. ABRASION FPE spectacles and goggles shall maximize resistance to scratching/ abrasion to minimize interference with vision...Visual Area ................................................................................. 2 3.0 BALLISTIC AND IMPACT RESISTANCE : BALLISTIC

Personality Patterns of Physicians in Person-Oriented and Technique-Oriented Specialties

ERIC Educational Resources Information Center

Borges, Nicole J.; Gibson, Denise D.

2005-01-01

This study investigated differences in personality patterns between person-oriented and technique-oriented physicians. It tested an integrative framework by converting the scores on the Personality Research Form (PRF) to the Big-Five factors and built a predictive model of group membership in clinical specialty area. PRF scores from 238 physicians…

Production of infectious ferret hepatitis E virus in a human hepatocarcinoma cell line PLC/PRF/5.

PubMed

Li, Tian-Cheng; Yoshizaki, Sayaka; Yang, Tingting; Kataoka, Michiyo; Nakamura, Tomofumi; Ami, Yasushi; Yuriko, Suzaki; Takeda, Naokazu; Wakita, Takaji

2016-02-02

A strain of ferret hepatitis E virus (HEV), sF4370, isolated from an imported ferret was used to inoculate a human hepatocarcinoma cell line, PLC/PRF/5. The virus genome and capsid protein were detected in the cell culture supernatant. Immunofluorescence microscopy indicated that the capsid protein was located in the cytoplasm. The virus particles were purified from the culture supernatant by sucrose gradient ultracentrifugation. The capsid protein with molecular mass of ∼72 kDa was detected in fractions with density of 1.150-1.162 g/cm(3), and particles of ferret HEV was associated with cell membrane. The virus recovered from the supernatant was serially passaged with PLC/PRF/5 cells and had the ability to infect ferrets by oral inoculation, indicating that the ferret HEV grown in PLC/PRF/5 was infectious. The establishment of ferret HEV cell culture system might be useful to understand the life cycle, mechanism of infection and replication of ferret HEV. Copyright © 2015 Elsevier B.V. All rights reserved.

Metabolic Genetic Screens Reveal Multidimensional Regulation of Virulence Gene Expression in Listeria monocytogenes and an Aminopeptidase That Is Critical for PrfA Protein Activation.

PubMed

Friedman, Sivan; Linsky, Marika; Lobel, Lior; Rabinovich, Lev; Sigal, Nadejda; Herskovits, Anat A

2017-06-01

Listeria monocytogenes is an environmental saprophyte and intracellular bacterial pathogen. Upon invading mammalian cells, the bacterium senses abrupt changes in its metabolic environment, which are rapidly transduced to regulation of virulence gene expression. To explore the relationship between L. monocytogenes metabolism and virulence, we monitored virulence gene expression dynamics across a library of genetic mutants grown under two metabolic conditions known to activate the virulent state: charcoal-treated rich medium containing glucose-1-phosphate and minimal defined medium containing limiting concentrations of branched-chain amino acids (BCAAs). We identified over 100 distinct mutants that exhibit aberrant virulence gene expression profiles, the majority of which mapped to nonessential metabolic genes. Mutants displayed enhanced, decreased, and early and late virulence gene expression profiles, as well as persistent levels, demonstrating a high plasticity in virulence gene regulation. Among the mutants, one was noteworthy for its particularly low virulence gene expression level and mapped to an X-prolyl aminopeptidase (PepP). We show that this peptidase plays a role in posttranslational activation of the major virulence regulator, PrfA. Specifically, PepP mediates recruitment of PrfA to the cytoplasmic membrane, a step identified as critical for PrfA protein activation. This study establishes a novel step in the complex mechanism of PrfA activation and further highlights the cross regulation of metabolism and virulence. Copyright © 2017 American Society for Microbiology.

Classification of platelet concentrates (Platelet-Rich Plasma-PRP, Platelet-Rich Fibrin-PRF) for topical and infiltrative use in orthopedic and sports medicine: current consensus, clinical implications and perspectives.

PubMed

Dohan Ehrenfest, David M; Andia, Isabel; Zumstein, Matthias A; Zhang, Chang-Qing; Pinto, Nelson R; Bielecki, Tomasz

2014-01-01

Platelet concentrates for topical and infiltrative use - commonly termed Platetet-Rich Plasma (PRP) or Platelet-Rich Fibrin (PRF) - are used or tested as surgical adjuvants or regenerative medicine preparations in most medical fields, particularly in sports medicine and orthopaedic surgery. Even if these products offer interesting therapeutic perspectives, their clinical relevance is largely debated, as the literature on the topic is often confused and contradictory. The long history of these products was always associated with confusions, mostly related to the lack of consensual terminology, characterization and classification of the many products that were tested in the last 40 years. The current consensus is based on a simple classification system dividing the many products in 4 main families, based on their fibrin architecture and cell content: Pure Platelet-Rich Plasma (P-PRP), such as the PRGF-Endoret technique; Leukocyte- and Platelet-Rich Plasma (LPRP), such as Biomet GPS system; Pure Platelet-Rich Fibrin (P-PRF), such as Fibrinet; Leukocyte- and Platelet-Rich Fibrin (L-PRF), such as Intra-Spin L-PRF. The 4 main families of products present different biological signatures and mechanisms, and obvious differences for clinical applications. This classification serves as a basis for further investigations of the effects of these products. Perspectives of evolutions of this classification and terminology are also discussed, particularly concerning the impact of the cell content, preservation and activation on these products in sports medicine and orthopaedics.

Ultrasound-Guided Pulsed Radiofrequency Stimulation of Posterior Tibial Nerve: A Potential Novel Intervention for Recalcitrant Plantar Fasciitis.

PubMed

Wu, Yung-Tsan; Chang, Chih-Ya; Chou, Yu-Ching; Yeh, Chun-Chang; Li, Tsung-Ying; Chu, Heng-Yi; Chen, Liang-Cheng

2017-05-01

To evaluate the therapeutic benefit of ultrasound-guided pulsed radiofrequency (PRF) stimulation at the posterior tibial nerve (PTN) in patients with recalcitrant plantar fasciitis (PF). A prospective, randomized, double-blinded, placebo-controlled trial (12-wk follow-up). Outpatient local medical center settings. Patients (N=36) with recalcitrant PF underwent randomization, and all were included in the final data analysis. Patients in the PRF group were treated with 1 dose of ultrasound-guided PRF stimulation at the PTN, and those in the control group received 1 dose of 2% lidocaine, 0.5mL, injected at the PTN under ultrasound guidance. The visual analog scale (first-step and overall pain), American Orthopedic Foot-Ankle Society (AOFAS) ankle-hindfoot scale, and ultrasonographic thickness of the plantar fascia were evaluated at 1, 4, 8, and 12 weeks after treatment. Thirty-six patients (20 feet per group) completed the study. The PRF group had a significantly larger improvement in first-step pain, overall pain, and AOFAS score (all P<.001), as well as plantar fascia thickness (P<.05), compared with those of the control group at all observed time points. This study shows that ultrasound-guided PRF stimulation at the PTN is effective for treating recalcitrant PF. This simple, reproducible method could be a novel strategy for managing recalcitrant PF. Copyright © 2016 American Congress of Rehabilitation Medicine. Published by Elsevier Inc. All rights reserved.

Biomechanical Stability of Dental Implants in Augmented Maxillary Sites: Results of a Randomized Clinical Study with Four Different Biomaterials and PRF and a Biological View on Guided Bone Regeneration

PubMed Central

Angelo, Troedhan; Marcel, Wainwright; Andreas, Kurrek; Izabela, Schlichting

2015-01-01

Introduction. Bone regenerates mainly by periosteal and endosteal humoral and cellular activity, which is given only little concern in surgical techniques and choice of bone grafts for guided bone regeneration. This study investigates on a clinical level the biomechanical stability of augmented sites in maxillary bone when a new class of moldable, self-hardening calcium-phosphate biomaterials (SHB) is used with and without the addition of Platelet Rich Fibrin (aPRF) in the Piezotome-enhanced subperiosteal tunnel-technique (PeSPTT). Material and Methods. 82 patients with horizontal atrophy of anterior maxillary crest were treated with PeSPTT and randomly assigned biphasic (60% HA/40% bTCP) or monophasic (100% bTCP) SHB without or with addition of aPRF. 109 implants were inserted into the augmented sites after 8.3 months and the insertion-torque-value (ITV) measured as clinical expression of the (bio)mechanical stability of the augmented bone and compared to ITVs of a prior study in sinus lifting. Results. Significant better results of (bio)mechanical stability almost by two-fold, expressed by higher ITVs compared to native bone, were achieved with the used biomaterials and more constant results with the addition of aPRF. Conclusion. The use of SHB alone or combined with aPRF seems to be favourable to achieve a superior (bio)mechanical stable restored alveolar bone. PMID:25954758

Evaluating temperature and fuel stratification for heat-release rate control in a reactivity-controlled compression-ignition engine using optical diagnostics and chemical kinetics modeling

DOE Office of Scientific and Technical Information (OSTI.GOV)

Musculus, Mark P. B.; Kokjohn, Sage L.; Reitz, Rolf D.

We investigated the combustion process in a dual-fuel, reactivity-controlled compression-ignition (RCCI) engine using a combination of optical diagnostics and chemical kinetics modeling to explain the role of equivalence ratio, temperature, and fuel reactivity stratification for heat-release rate control. An optically accessible engine is operated in the RCCI combustion mode using gasoline primary reference fuels (PRF). A well-mixed charge of iso-octane (PRF = 100) is created by injecting fuel into the engine cylinder during the intake stroke using a gasoline-type direct injector. Later in the cycle, n-heptane (PRF = 0) is delivered through a centrally mounted diesel-type common-rail injector. This injectionmore » strategy generates stratification in equivalence ratio, fuel blend, and temperature. The first part of this study uses a high-speed camera to image the injection events and record high-temperature combustion chemiluminescence. Moreover, the chemiluminescence imaging showed that, at the operating condition studied in the present work, mixtures in the squish region ignite first, and the reaction zone proceeds inward toward the center of the combustion chamber. The second part of this study investigates the charge preparation of the RCCI strategy using planar laser-induced fluorescence (PLIF) of a fuel tracer under non-reacting conditions to quantify fuel concentration distributions prior to ignition. The fuel-tracer PLIF data show that the combustion event proceeds down gradients in the n-heptane distribution. The third part of the study uses chemical kinetics modeling over a range of mixtures spanning the distributions observed from the fuel-tracer fluorescence imaging to isolate the roles of temperature, equivalence ratio, and PRF number stratification. The simulations predict that PRF number stratification is the dominant factor controlling the ignition location and growth rate of the reaction zone. Equivalence ratio has a smaller, but still significant, influence. Lastly, temperature stratification had a negligible influence due to the NTC behavior of the PRF mixtures.« less

Evaluating temperature and fuel stratification for heat-release rate control in a reactivity-controlled compression-ignition engine using optical diagnostics and chemical kinetics modeling

DOE PAGES

Musculus, Mark P. B.; Kokjohn, Sage L.; Reitz, Rolf D.

2015-04-23

We investigated the combustion process in a dual-fuel, reactivity-controlled compression-ignition (RCCI) engine using a combination of optical diagnostics and chemical kinetics modeling to explain the role of equivalence ratio, temperature, and fuel reactivity stratification for heat-release rate control. An optically accessible engine is operated in the RCCI combustion mode using gasoline primary reference fuels (PRF). A well-mixed charge of iso-octane (PRF = 100) is created by injecting fuel into the engine cylinder during the intake stroke using a gasoline-type direct injector. Later in the cycle, n-heptane (PRF = 0) is delivered through a centrally mounted diesel-type common-rail injector. This injectionmore » strategy generates stratification in equivalence ratio, fuel blend, and temperature. The first part of this study uses a high-speed camera to image the injection events and record high-temperature combustion chemiluminescence. Moreover, the chemiluminescence imaging showed that, at the operating condition studied in the present work, mixtures in the squish region ignite first, and the reaction zone proceeds inward toward the center of the combustion chamber. The second part of this study investigates the charge preparation of the RCCI strategy using planar laser-induced fluorescence (PLIF) of a fuel tracer under non-reacting conditions to quantify fuel concentration distributions prior to ignition. The fuel-tracer PLIF data show that the combustion event proceeds down gradients in the n-heptane distribution. The third part of the study uses chemical kinetics modeling over a range of mixtures spanning the distributions observed from the fuel-tracer fluorescence imaging to isolate the roles of temperature, equivalence ratio, and PRF number stratification. The simulations predict that PRF number stratification is the dominant factor controlling the ignition location and growth rate of the reaction zone. Equivalence ratio has a smaller, but still significant, influence. Lastly, temperature stratification had a negligible influence due to the NTC behavior of the PRF mixtures.« less

Percutaneous Cervical Nucleoplasty vs. Pulsed Radio Frequency of the Dorsal Root Ganglion in Patients with Contained Cervical Disk Herniation; A Prospective, Randomized Controlled Trial.

PubMed

Halim, Willy; van der Weegen, Walter; Lim, Toine; Wullems, Jorgen Antonin; Vissers, Kris Christiaan

2017-07-01

Cervical neck pain is often caused by cervical disk pathology and may cause severe symptoms and disability. Surgeons and patients are increasingly aware of postsurgery-related complications. This stimulated the clinical usage of minimally invasive treatments such as percutaneous nucleoplasty (PCN) and pulsed radio frequency (PRF). However, scientific evidence on both treatments is limited. Our objective was to evaluate the efficacy of PCN compared to PRF in patients with contained cervical disk herniation. A prospective randomized clinical trial was conducted including 34 patients with radicular pain due to a single contained cervical disk herniation who were treated with either PCN or PRF. Demographic data were collected, and the Medical Outcomes Study 12-Item Short Form (SF-12) Health Survey, visual analog scale (VAS), and the Neck Disability Index (NDI) were completed 1, 2, and 3 months after treatment. Treatment satisfaction and complications were recorded. In the PCN group (n = 17, mean age 52.4 years, 10 female/7 male), patients were treated at C5 to C6 (8 cases) or C6 to C7 (9 cases). In the PRF group (n = 17, mean age 49.5 years, 8 female/9 male), patients were treated at C3 to C4 (1 case), C5 to C6 (10 cases), or C6 to C7 (6 cases). At 3 months, mean pain VAS improved significantly from baseline in the PCN group (mean improvement: 43.4 points) and in the PRF group (34.0 points). However, improvement in 1 group was not superior compared to the other group (P = 0.48). No serious complications were reported. Within 3 months, both PCN and PRF show significant pain improvement in patients with contained cervical disk herniation, but none is superior to the other. Both treatment options appear to be effective and safe in regular clinical practice. © 2016 World Institute of Pain.

Characterization of Ribosomal Frameshifting in Theiler's Murine Encephalomyelitis Virus

PubMed Central

Finch, Leanne K.; Ling, Roger; Napthine, Sawsan; Olspert, Allan; Michiels, Thomas; Lardinois, Cécile; Bell, Susanne; Loughran, Gary; Brierley, Ian

2015-01-01

ABSTRACT Theiler's murine encephalomyelitis virus (TMEV) is a member of the genus Cardiovirus in the Picornaviridae, a family of positive-sense single-stranded RNA viruses. Previously, we demonstrated that in the related cardiovirus, Encephalomyocarditis virus, a programmed −1 ribosomal frameshift (−1 PRF) occurs at a conserved G_GUU_UUU sequence within the 2B-encoding region of the polyprotein open reading frame (ORF). Here we show that −1 PRF occurs at a similar site during translation of the TMEV genome. In addition, we demonstrate that a predicted 3′ RNA stem-loop structure at a noncanonical spacing downstream of the shift site is required for efficient frameshifting in TMEV and that frameshifting also requires virus infection. Mutating the G_GUU_UUU shift site to inhibit frameshifting results in an attenuated virus with reduced growth kinetics and a small-plaque phenotype. Frameshifting in the virus context was found to be extremely efficient at 74 to 82%, which, to our knowledge, is the highest frameshifting efficiency recorded to date for any virus. We propose that highly efficient −1 PRF in TMEV provides a mechanism to escape the confines of equimolar expression normally inherent in the single-polyprotein expression strategy of picornaviruses. IMPORTANCE Many viruses utilize programmed −1 ribosomal frameshifting (−1 PRF) to produce different protein products at a defined ratio, or to translate overlapping ORFs to increase coding capacity. With few exceptions, −1 PRF occurs on specific “slippery” heptanucleotide sequences and is stimulated by RNA structure beginning 5 to 9 nucleotides (nt) downstream of the slippery site. Here we describe an unusual case of −1 PRF in Theiler's murine encephalomyelitis virus (TMEV) that is extraordinarily efficient (74 to 82% of ribosomes shift into the alternative reading frame) and, in stark contrast to other examples of −1 PRF, is dependent upon a stem-loop structure beginning 14 nt downstream of the slippery site. Furthermore, in TMEV-based reporter constructs in transfected cells, efficient frameshifting is critically dependent upon virus infection. We suggest that TMEV evolved frameshifting as a novel mechanism for removing ribosomes from the message (a “ribosome sink”) to downregulate synthesis of the 3′-encoded replication proteins. PMID:26063423

A rapid seedling resistance assay identifies wild tomato lines that are resistant to Psuedomonas syringe pv. tomato race 1

USDA-ARS?s Scientific Manuscript database

Bacterial speck caused by Pseudomonas syringae has historically been controlled by the Pto/Prf gene cluster. Emerging strains like P. syringae pv. tomato race 1 overcome resistance conferred by Pto/Prf, and can cause serious crop loss under appropriate environmental conditions. We developed a rapid ...

Characterization of Leukocyte-platelet Rich Fibrin, A Novel Biomaterial.

PubMed

Madurantakam, Parthasarathy; Yoganarasimha, Suyog; Hasan, Fadi K

2015-09-29

Autologous platelet concentrates represent promising innovative tools in the field of regenerative medicine and have been extensively used in oral surgery. Unlike platelet rich plasma (PRP) that is a gel or a suspension, Leukocyte-Platelet Rich Fibrin (L-PRF) is a solid 3D fibrin membrane generated chair-side from whole blood containing no anti-coagulant. The membrane has a dense three dimensional fibrin matrix with enriched platelets and abundant growth factors. L-PRF is a popular adjunct in surgeries because of its superior handling characteristics as well as its suturability to the wound bed. The goal of the study is to demonstrate generation as well as provide detailed characterization of relevant properties of L-PRF that underlie its clinical success.

Measuring Low-PRF Pulsed Signals with a Standard HP 8510B Vector Network Analyzer Within Milliseconds (Het Meten van Lage-PRF Gepulste Signalen met een Standaard HP 8510B Vector Network Analyzer Binnen Enkele Milliseconden)

DTIC Science & Technology

1990-08-01

reference signal 25 5 A METHOD FOR MEASURING LOW-PRF PULSED SIGNALS 28 5.1 Using a NWA with a smaller BPF 28 5.2 Using the HP 8510B external trigger...2nd LO 11Q 3MHz BPF lOkHz BPF Fig. 4: Receiver block diagram The receiver is a double conversion superheterodyne with a 10 kHz wide BandPass Filter... BPF ) in the second IF. This 10 kHz filter is the component that dictates how the HP 8510B responds to pulsed signals. For the pulsed-RF test signal

Feasibility study for removing calcified material using a planar rectangular ultrasound transducer.

PubMed

Damianou, Christakis; Couppis, Andreas

2016-01-01

The aim of the proposed study was to conduct a feasibility study using a flat rectangular (3 mm × 10 mm) MRI compatible transducer operating at 5.3 MHz for destroying calcified material in an in vitro model. The proposed method can be used in the future for treating atherosclerosis plaques of the coronary, carotid or peripheral arteries. The system was tested initially on calcium rods. Another test was performed in a hydroxyapatite-polylactide model. A parametric study was performed where the mass of calcified material removed was studied as a function of intensity, pulse repetition frequency (PRF), duty factor (DF) and presence of bubbles. The amount of calcified material removed is directly related to the intensity, PRF and DF. It was found that the presence of bubbles accelerates the removal of calcified material. In order to ensure that pure mechanical mode ultrasound was used, the protocols were designed so that the temperature does not exceed 1 °C.

Clinical and radiographic evaluation of nanocrystalline hydroxyapatite with or without platelet-rich fibrin membrane in the treatment of periodontal intrabony defects

PubMed Central

Elgendy, Enas Ahmed; Abo Shady, Tamer Elamer

2015-01-01

Background: Nano-sized ceramics may represent a promising class of bone graft substitutes due to their improved osseointegrative properties. Nanocrystalline hydroxyapatite (NcHA) binds to bone and stimulate bone healing by stimulation of osteoblast activity. Platelet-rich fibrin (PRF), an intimate assembly of cytokines, glycan chains, and structural glycoproteins enmeshed within a slowly polymerized fibrin network, has the potential to accelerate soft and hard tissue healing. The present study aims to explore the clinical and radiographical outcome of NcHA bone graft with or without PRF, in the treatment of intrabony periodontal defects. Materials and Methods: In a split-mouth study design, 20 patients having two almost identical intrabony defects with clinical probing depth of at least 6 mm were selected for the study. Selected sites were randomly divided into two groups. In Group I, mucoperiosteal flap elevation followed by the placement of NcHA was done. In Group II, mucoperiosteal flap elevation, followed by the placement of NcHA with PRF was done. Clinical and radiographic parameters were recorded at baseline and at 6-month postoperatively. Results: Both treatment groups showed a significant probing pocket depth (PPD) reduction, clinical attachment gain, increase bone density 6-month after surgery compared with baseline. However, there was a significantly greater PPD reduction and clinical attachment gain when PRF was added to NcHA. Conclusion: The NcHA bone graft in combination with PRF demonstrated clinical advantages beyond that achieved by the NcHA alone. PMID:25810595

Effect of osteogenic periosteal distraction by a modified Hyrax device with and without platelet-rich fibrin on bone formation in a rabbit model: a pilot study.

PubMed

Pripatnanont, P; Balabid, F; Pongpanich, S; Vongvatcharanon, S

2015-05-01

This study evaluated the effect of a modified Hyrax device and platelet-rich fibrin (PRF) on osteogenic periosteal distraction (OPD). Twelve adult male New Zealand white rabbits were separated into two main groups (six in each) according to the duration of the consolidation period (4 or 8 weeks). In each main group, the animals underwent OPD of the left and right sides of the mandible and were divided into four subgroups (three animals per group): device vs. device+PRF, and PRF vs. sham. Radiographic, histological, histomorphometric, and micro-computed tomography (micro-CT) analyses were performed. New bone formation was observed on the lateral and vertical sides of the mandible of all groups. Micro-CT and histomorphometry showed that the device+PRF group presented the highest percentages of bone volume and bone area at 4 weeks (56.67 ± 12.67%, 41.37 ± 7.57%) and at 8 weeks (49.67 ± 8.33%, 55.46 ± 10.67%; significantly higher than the other groups, P<0.001), followed by the device group at 4 weeks (33.00 ± 1.73%, 33.21 ± 11.00%) and at 8 weeks (30.00 ± 3.00%, 23.25 ± 5.46%). In conclusion, the modified Hyrax device was used successfully for OPD in a rabbit model to gain vertical ridge augmentation, and greater bone maturation was achieved with the addition of PRF. Copyright © 2014 International Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.

Role of pH Changes on Transforming Growth Factor-β1 Release and on the Fibrin Architecture of Platelet-rich Fibrin When Layered with Biodentine, Glass Ionomer Cement, and Intermediate Restorative Material.

PubMed

Mullaguri, Harish; Suresh, Nandini; Surendran, Smitha; Velmurugan, Natanasabapathy; Chitra, Selvarajan

2016-05-01

The purpose of this study was to evaluate the influence of pH that is due to setting reaction of Biodentine, glass ionomer cement (GIC), and intermediate restorative material (IRM) on transforming growth factor-β1 (TGF-β1) release and on the fibrin architecture of platelet-rich fibrin (PRF). PRF was obtained from 8 volunteers and layered over the freshly prepared GIC, IRM, and Biodentine mixtures. TGF-β1 release was estimated by using enzyme-linked immunosorbent assay (ELISA), and fibrin structure of PRF was analyzed by using scanning electron microscope at 1 and 5 hours. Biodentine, GIC, and IRM increased the TGF-β1 release in comparison with that of control group (PRF alone) at both 1 and 5 hours. Biodentine released significantly more TGF-β1 than GIC and IRM at 1 hour. At 5 hours both GIC and Biodentine released significantly more TGF-β1 than IRM. The fibrin architecture of the Biodentine group was similar to that of control group at both 1 and 5 hours. In GIC and IRM groups the fibrillar structure of fibrin was collapsed, ill-defined, and cloudy with very thick fibers and irregularly reduced porosities. Biodentine induces larger amount of TGF-β1 release and also maintains the integrity of fibrin structure when compared with GIC and IRM when layered over PRF. Copyright © 2016 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

Classification of platelet concentrates (Platelet-Rich Plasma-PRP, Platelet-Rich Fibrin-PRF) for topical and infiltrative use in orthopedic and sports medicine: current consensus, clinical implications and perspectives

PubMed Central

Dohan Ehrenfest, David M.; Andia, Isabel; Zumstein, Matthias A.; Zhang, Chang-Qing; Pinto, Nelson R.; Bielecki, Tomasz

2014-01-01

Summary Platelet concentrates for topical and infiltrative use – commonly termed Platetet-Rich Plasma (PRP) or Platelet-Rich Fibrin (PRF) – are used or tested as surgical adjuvants or regenerative medicine preparations in most medical fields, particularly in sports medicine and orthopaedic surgery. Even if these products offer interesting therapeutic perspectives, their clinical relevance is largely debated, as the literature on the topic is often confused and contradictory. The long history of these products was always associated with confusions, mostly related to the lack of consensual terminology, characterization and classification of the many products that were tested in the last 40 years. The current consensus is based on a simple classification system dividing the many products in 4 main families, based on their fibrin architecture and cell content: Pure Platelet-Rich Plasma (P-PRP), such as the PRGF-Endoret technique; Leukocyte- and Platelet-Rich Plasma (LPRP), such as Biomet GPS system; Pure Platelet-Rich Fibrin (P-PRF), such as Fibrinet; Leukocyte- and Platelet-Rich Fibrin (L-PRF), such as Intra-Spin L-PRF. The 4 main families of products present different biological signatures and mechanisms, and obvious differences for clinical applications. This classification serves as a basis for further investigations of the effects of these products. Perspectives of evolutions of this classification and terminology are also discussed, particularly concerning the impact of the cell content, preservation and activation on these products in sports medicine and orthopaedics. PMID:24932440

Risk of Behavioral and Adaptive Functioning Difficulties in Youth with Previous and Current Sleep Disordered Breathing

PubMed Central

Perfect, Michelle M.; Archbold, Kristen; Goodwin, James L.; Levine-Donnerstein, Deborah; Quan, Stuart F.

2013-01-01

Objectives: To examine the rates of behavioral and adaptive functioning difficulties among youth who never had sleep disordered breathing (SDB), had remitted SDB, had incident SDB, or had persistent SDB; and to determine if there were increased odds of behavioral difficulties among youth with varying SDB histories relative to those who never had SDB. Methods: 263 youth had valid polysomnography and neurobehavioral data at two time points approximately 5 years apart from the prospective Tucson Children's Assessment of Sleep Apnea study. Primary outcomes were the Behavior Assessment Scale for Children-2nd Edition Parent Report Form (BASC-PRF) and Self-Report of Personality (SRP), and the Adaptive Behavior Assessment System-2nd Edition (ABAS-2). Results: Compared to those who never had SDB, individuals with persistent SDB had significant odds and met more cutoff scores on the BASC-2-PRF Externalizing Problems Composite (odds ratio [OR] 3.29; 8.92% vs. 35.3%), Behavioral Symptoms Index (OR 6.82; 7.4% vs. 35.3%) and Hyperactivity subscale (OR 6.82; 11.1% vs. 41.2%). Similarly, greater difficulties was seen for the group with persistent SDB (relative to never) on the ABAS-2 Social Domain (OR 3.39; 22% vs. 50%), and Communication (OR 4.26; 15% vs. 42.9%) and Self-Care subscales (OR = 2.97; 25.2% vs. 50%). Relative to youth who never had SDB, youth who developed SDB at Time 2 had compromised adaptive skills as evidenced by the BASC-2 PRF Adaptive Behavior Composite (OR 3.34; 15.6% vs. 38.1%) and the ABAS-2 General Adaptive Composite (OR 2.83; 20.5% vs. 42.1%). Conclusions: Youth with current SDB exhibited hyperactivity, attention problems, aggressivity, lower social competency, poorer communication, and/or diminished adaptive skills. Citation: Perfect MM; Archbold K; Goodwin JL; Levine-Donnerstein D; Quan SF. Risk of behavioral and adaptive functioning difficulties in youth with previous and current sleep disordered breathing. SLEEP 2013;36(4):517-525. PMID:23543901

Platelet-Rich Fibrin Improves the Viability of Diced Cartilage Grafts in a Rabbit Model.

PubMed

Göral, Ali; Aslan, Cem; Bolat Küçükzeybek, Betül; Işık, Dağhan; Hoşnuter, Mübin; Durgun, Mustafa

2016-04-01

Diced cartilage may be wrapped with synthetic or biological materials before grafting to a recipient site. These materials have unique advantages and disadvantages, and a gold standard is not available. The authors investigated the effects of platelet-rich fibrin (PRF) on the survival of cartilage grafts in a rabbit model. In this experimental study, diced cartilage pieces from the ears of 9 male rabbits were left unwrapped or were wrapped with PRF, oxidized regenerated cellulose, or fascia. Specimens then were placed into subcutaneous pockets prepared on the backs of the rabbits. The animals were sacrificed 2 months after the procedure, and the grafts were excised for macroscopic and histopathologic examination. The cartilage graft wrapped with PRF showed superior viability compared with the cartilage graft wrapped with oxidized regenerated cellulose. No significant differences were found among the other groups. The groups were not significantly different in terms of rates of inflammation, fibrosis, or vascularization. PRF enhances the viability of diced cartilage grafts and should be considered an appropriate biological wrapping material for cartilage grafting. © 2016 The American Society for Aesthetic Plastic Surgery, Inc. Reprints and permission: journals.permissions@oup.com.

Transformation of Rhodococcus fascians by High-Voltage Electroporation and Development of R. fascians Cloning Vectors

PubMed Central

Desomer, Jan; Dhaese, Patrick; Montagu, Marc Van

1990-01-01

The analysis of the virulence determinants of phytopathogenic Rhodococcus fascians has been hampered by the lack of a system for introducing exogenous DNA. We investigated the possibility of genetic transformation of R. fascians by high-voltage electroporation of intact bacterial cells in the presence of plasmid DNA. Electrotransformation in R. fascians D188 resulted in transformation frequencies ranging from 105/μg of DNA to 107/μg of DNA, depending on the DNA concentration. The effects of different electrical parameters and composition of electroporation medium on transformation efficiency are presented. By this transformation method, a cloning vector (pRF28) for R. fascians based on an indigenous 160-kilobase (chloramphenicol and cadmium resistance-encoding) plasmid pRF2 from strain NCPPB 1675 was developed. The origin of replication and the chloramphenicol resistance gene on pRF28 were used to construct cloning vectors that are capable of replication in R. fascians and Escherichia coli. The electroporation method presented was efficient enough to allow detection of the rare integration of replication-deficient pRF28 derivatives in the R. fascians D188 genome via either homologous or illegitimate recombination. Images PMID:16348290

Differential effects of NMDA antagonists microinjections into the nucleus reticularis pontis caudalis on seizures induced by pentylenetetrazol in the rat.

PubMed

Manjarrez, J; Alvarado, R; Camacho-Arroyo, I

2001-07-01

It has been shown that NMDA antagonists block the tonic but not the clonic component of seizures when they are injected in the oral region of the rat pontine reticular formation (PRF). The participation of the caudal PRF in the effects of NMDA antagonists upon the tonic and the clonic components of generalized seizures induced by pentylenetetrazol (PTZ) is unknown. The aim of the present study was to evaluate the effects of unilateral microinjections of competitive and non-competitive NMDA antagonists, 2-amino-7-phosphonoheptanoic acid (AP-7) and dizocilpine (MK-801), respectively, into the nucleus reticularis pontis caudalis of the rat PRF upon seizures induced by PTZ (70 mg/kg i.p.). MK-801 induced a dose-related decrease both in the incidence of generalized tonic-clonic seizures (GTCS) and in the presence of spikes in the EEG. MK-801 also increased GTCS latency. On the contrary, AP-7 did not have effects on GTCS. Interestingly, it induced ipsilateral circling behavior. These results suggest that in the caudal region of the rat PRF only non-competitive NMDA antagonists should block the generation of tonic and clonic components of generalized seizures.

High-pulse energy-stabilized passively mode-locked external cavity inverse bow-tie 980nm laser diode for space applications

NASA Astrophysics Data System (ADS)

Krakowski, M.; Resneau, P.; Garcia, M.; Vinet, E.; Robert, Y.; Lecomte, M.; Parillaud, O.; Gerard, B.; Kundermann, S.; Torcheboeuf, N.; Boiko, D. L.

2018-02-01

We report on multi-section inverse bow-tie laser producing mode-locked pulses of 90 pJ energy and 6.5 ps width (895 fs after compression) at 1.3 GHz pulse repetition frequency (PRF) and consuming 2.9 W of electric power. The laser operates in an 80 mm long external cavity. By translation of the output coupling mirror, the PRF was continuously tuned over 37 MHz range without additional adjustments. Active stabilization with a phase lock loop actuating on the driving current has allowed us to reach the PRF relative stability at a 2·10-10 level on 10 s intervals, as required by the European Space Agency (ESA) for inter-satellite long distance measurements.

Pulsed Radiofrequency Applied to the Sciatic Nerve Improves Neuropathic Pain by Down-regulating The Expression of Calcitonin Gene-related Peptide in the Dorsal Root Ganglion

PubMed Central

Ren, Hao; Jin, Hailong; Jia, Zipu; Ji, Nan; Luo, Fang

2018-01-01

Background: Clinical studies have shown that applying pulsed radiofrequency (PRF) to the neural stem could relieve neuropathic pain (NP), albeit through an unclear analgesic mechanism. And animal experiments have indicated that calcitonin gene-related peptide (CGRP) expressed in the dorsal root ganglion (DRG) is involved in generating and maintaining NP. In this case, it is uncertain whether PRF plays an analgesic role by affecting CGRP expression in DRG. Methods: Rats were randomly divided into four groups: Groups A, B, C, and D. In Groups C and D, the right sciatic nerve was ligated to establish the CCI model, while in Groups A and B, the sciatic nerve was isolated without ligation. After 14 days, the right sciatic nerve in Groups B and D re-exposed and was treated with PRF on the ligation site. Thermal withdrawal latency (TWL) and hindpaw withdrawal threshold (HWT) were measured before PRF treatment (Day 0) as well as after 2, 4, 8, and 14 days of treatment. At the same time points of the behavioral tests, the right L4-L6 DRG was sampled and analyzed for CGRP expression using RT-qPCR and an enzyme-linked immunosorbent assay (ELISA). Results: Fourteen days after sciatic nerve ligation, rats in Groups C and D had a shortened TWL (P<0.001) and a reduced HWT (P<0.001) compared to those in Groups A and B. After PRF treatment, the TWL of the rats in Group D gradually extended with HWT increasing progressively. Prior to PRF treatment (Day 0), CGRP mRNA expressions in the L4-L6 DRG of Groups C and D increased significantly (P<0.001) and were 2.7 and 2.6 times that of Group A respectively. ELISA results showed that the CGRP content of Groups C and D significantly increased in comparison with that of Groups A and B (P<0.01). After PRF treatment, the mRNA expression in the DRG of Group D gradually decreased and the mRNA expression was 1.7 times that of Group A on the 4th day(P> 0.05). On the 8th and 14th days, the mRNA levels in Group D were restored to those of Groups A and B. Meanwhile, the CGRP content of Group D gradually dropped over time, from 76.4 pg/mg (Day 0) to 57.5 pg/mg (Day 14). Conclusions: In this study, we found that, after sciatic nerve ligation, rats exhibited apparent hyperalgesia and allodynia, and CGRP mRNA and CGRP contents in the L4-L6 DRG increased significantly. Through lowering CGRP expression in the DRG, PRF treatment might relieve the pain behaviors of NP. PMID:29333099

Role of the Prospect Rock Fault in the Exhumation of High Pressure Rocks in North-Central Vermont

NASA Astrophysics Data System (ADS)

Tam, E.; Webb, L. E.; Aiken, C. L.

2017-12-01

The Prospect Rock Fault (PRF) is key to our interpretation of regional deformation and exhumation of blueschist and eclogite-facies rocks in the Tillotson Peak Complex (TPC) during the Taconic Orogeny. The TPC is in the footwall of the PRF in the eastern limb of the Green Mountain Anticlinorium. In the TPC, the dominant foliation is S2 and E-W trending F2 folds parallel L2 lineations, which run orthogonal to regional N-S trending folds associated with the Taconic Orogeny. This structural trend has possible analogies with HP-UHP terranes in Papua New Guinea and China. The PRF itself is folded by F2 folds. Presently, there is a lack of consensus about the structural evolution of the PRF and its role in the exhumation of the TPC, and studies have not reconciled the formation of the E-W folds and lineations to a regional model. Oriented samples and structural data were collected from the footwall of the PRF over several transects. Samples were processed into orthogonal thin sections for microstructural analyses and for 40Ar/39Ar step-heating of white mica. Preliminary results show a range of ages from 458.6 ± 2.0 Ma to 420.0 ± 2.7 Ma. The oldest ages are just slightly younger, yet concordant, with published and new 40Ar/39Ar ages from the TPC. The dominant foliation in the PRF samples, S2, is defined in thin section by mica and quartz microlithons, and oriented mica grains. S1 is only locally preserved in some mica domains and albite/garnet inclusion trails. S3 appears as crenulations of S2, with no significant new mineral crystallization. In the field, L2 lineations are defined by mineral and quartz rods, and L3 lineations are defined as intersection lineations on S2 surfaces. The relationships between ages and microstructures are consistent younger ages being associated with increased presence of S3 crenulation foliations, which appeared in structurally lower areas. Samples with older ages display dominant S2 foliations and lack S3 crenulations, and were sourced from structurally higher areas. Our results suggest the PRF played a role in exhumation of the TPC and ages obtained are closely aligned with deformation ages constrained from 40Ar/39Ar dating in southern Quebec for the Taconic D2 and Salinian D3 deformation. These dates may aid to further correlation tectonostratographic models between southern Quebec and northern Vermont.

Platelet rich fibrin: A new covering material for oral mucosal defects.

PubMed

Mohanty, Sujata; Pathak, Himani; Dabas, Jitender

2014-01-01

In the current oral and maxillofacial surgery practice, the use of PRF membrane is limited to bony lesions and gingival defects. We have used it for reconstruction of benign hyperkeratotic lesion of oral mucosa in a healthy adult male and have found good healing clinically. It is suggested that the use of PRF membrane could be tried for various other superficial oral mucosal lesions.

Leukocyte- and platelet-rich fibrin (L-PRF) for long-term delivery of growth factor in rotator cuff repair: review, preliminary results and future directions.

PubMed

Zumstein, Matthias A; Berger, Simon; Schober, Martin; Boileau, Pascal; Nyffeler, Richard W; Horn, Michael; Dahinden, Clemens A

2012-06-01

Surgical repair of the rotator cuff repair is one of the most common procedures in orthopedic surgery. Despite it being the focus of much research, the physiological tendon-bone insertion is not recreated following repair and there is an anatomic non-healing rate of up to 94%. During the healing phase, several growth factors are upregulated that induce cellular proliferation and matrix deposition. Subsequently, this provisional matrix is replaced by the definitive matrix. Leukocyte- and platelet-rich fibrin (L-PRF) contain growth factors and has a stable dense fibrin matrix. Therefore, use of LPRF in rotator cuff repair is theoretically attractive. The aim of the present study was to determine 1) the optimal protocol to achieve the highest leukocyte content; 2) whether L-PRF releases growth factors in a sustained manner over 28 days; 3) whether standard/gelatinous or dry/compressed matrix preparation methods result in higher growth factor concentrations. 1) The standard L-PRF centrifugation protocol with 400 x g showed the highest concentration of platelets and leukocytes. 2) The L-PRF clots cultured in medium showed a continuous slow release with an increase in the absolute release of growth factors TGF-β1, VEGF and MPO in the first 7 days, and for IGF1, PDGF-AB and platelet activity (PF4=CXCL4) in the first 8 hours, followed by a decrease to close to zero at 28 days. Significantly higher levels of growth factor were expressed relative to the control values of normal blood at each culture time point. 3) Except for MPO and the TGFβ-1, there was always a tendency towards higher release of growth factors (i.e., CXCL4, IGF-1, PDGF-AB, and VEGF) in the standard/gelatinous- compared to the dry/compressed group. L-PRF in its optimal standard/gelatinous-type matrix can store and deliver locally specific healing growth factors for up to 28 days and may be a useful adjunct in rotator cuff repair.

Expression of CD133 confers malignant potential by regulating metalloproteinases in human hepatocellular carcinoma.

PubMed

Kohga, Keisuke; Tatsumi, Tomohide; Takehara, Tetsuo; Tsunematsu, Hinako; Shimizu, Satoshi; Yamamoto, Masashi; Sasakawa, Akira; Miyagi, Takuya; Hayashi, Norio

2010-06-01

Although CD133 expression is identified as a cancer stem cell marker of hepatocellular carcinoma (HCC), the detailed characteristics of HCC cells expressing CD133 remain unclear. We examined the malignant characteristics of CD133-expressing HCC cells. CD133-expressing cells could be detected with low frequency in 5 HCC tissues. We derived two different HCC cell lines by (1) transfection of CD133 siRNA in PLC/PRF/5 cells in (CD133si-PLC/PRF/5), and (2) by a magnetic cell sorting method that allowed to divide Huh7 cells into two CD133 positive (+) and negative (-) groups. CD133 knockdown in PLC/PRF/5 cells resulted in a decrease of the mRNA and protein expressions of matrix metalloproteinase (MMP)-2 and a disintegrin and metalloproteinase (ADAM)9. We next examined the malignant characteristics related to decreasing MMP-2 and ADAM9 in HCC cells. In CD133si-PLC/PRF/5 cells and CD133- Huh7 cells, invasiveness and vascular endothelial growth factor (VEGF) production, which are both related to the activity of MMP-2, were inhibited compared CD133-expressing HCC cells. We previously demonstrated that ADAM9 protease plays critical roles in the shedding of MHC class I-related chain A (MICA) which regulates the sensitivity of tumor cells to natural killer cells (NK). Decreasing ADAM9 expression in CD133si-PLC/PRF/5 cells and CD133- Huh7 cells resulted in an increase in membrane-bound MICA and a decrease in soluble MICA production. Both CD133si-PLC/PRF/5 cells and CD133- Huh7 cells were susceptible to NK activity, depending on the expression levels of membrane-bound MICA, but CD133-expressing HCC cells were not. These results demonstrate that CD133 expression in HCC cells confers malignant potential which may contribute to the survival of HCC cells. Copyright 2010 European Association for the Study of the Liver. Published by Elsevier B.V. All rights reserved.

Improvement in the repair of defects in maxillofacial soft tissue in irradiated minipigs by a mixture of adipose-derived stem cells and platelet-rich fibrin.

PubMed

Chen, Yuanzheng; Niu, Zhanguo; Xue, Yan; Yuan, Fukang; Fu, Yanjie; Bai, Nan

2014-10-01

To find out if adipose-derived stem cells (ASC) and platelet-rich fibrin (PRF), alone or combined, had any effect on the repair of maxillofacial soft tissue defects in irradiated minipigs, ASC were isolated, characterised, and expanded. Twenty female minipigs, the right parotid glands of which had been irradiated, were randomly divided into 4 groups of 5 each: those in the first group were injected with both ASC and PRF (combined group), the second group was injected with ASC alone (ASC group), the third group with PRF alone (PRF group), and the fourth group with phosphate buffer saline (PBS) (control group). Six months after the last injection, the size and depth of each defect were assessed, and subcutaneous tissues were harvested, stained with haematoxylin and eosin, and examined immunohistologically and for apoptosis. Expanded cells were successfully isolated and identified. Six months after injection the defects in the 3 treated groups were significantly smaller (p<0.001) and shallower (p<0.001) than those in the control group. Those in the combined group were the smallest and shallowest. Haematoxylin and eosin showed that the 3 treated groups contained more subcutaneous adipose tissue than the control group, and also had significantly greater vascular density (p<0.001) and fewer apoptotic cells (p<0.001). Both ASC and PRF facilitate the repair of defects in maxillofacial soft tissue in irradiated minipigs, and their combined use is more effective than their use as single agents. Copyright © 2014 The British Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.

Combination of Mineral Trioxide Aggregate and Platelet-rich Fibrin Promotes the Odontoblastic Differentiation and Mineralization of Human Dental Pulp Cells via BMP/Smad Signaling Pathway.

PubMed

Woo, Su-Mi; Kim, Won-Jae; Lim, Hae-Soon; Choi, Nam-Ki; Kim, Sun-Hun; Kim, Seon-Mi; Jung, Ji-Yeon

2016-01-01

Recent reports have shown that the combined use of platelet-rich fibrin (PRF), an autologous fibrin matrix, and mineral trioxide aggregate (MTA) as root filling material is beneficial for the endodontic management of an open apex. However, the potential of the combination of MTA and PRF as an odontogenic inducer in human dental pulp cells (HDPCs) in vitro has not yet been studied. The purpose of this study was to evaluate the effect of the combination of MTA and PRF on odontoblastic maturation in HDPCs. HDPCs extracted from third molars were directly cultured with MTA and PRF extract (PRFe). Odontoblastic differentiation of HDPCs was evaluated by measuring the alkaline phosphatase (ALP) activity, and the expression of odontogenesis-related genes was detected using reverse-transcription polymerase chain reaction or Western blot. Mineralization formation was assessed by alizarin red staining. HDPCs treated with MTA and PRFe significantly up-regulated the expression of dentin sialoprotein and dentin matrix protein-1 and enhanced ALP activity and mineralization compared with those with MTA or PRFe treatment alone. In addition, the combination of MTA and PRFe induced the activation of bone morphogenic proteins (BMP)/Smad, whereas LDN193189, the bone morphogenic protein inhibitor, attenuated dentin sialophosphoprotein and dentin matrix protein-1 expression, ALP activity, and mineralization enhanced by MTA and PRFe treatment. This study shows that the combination of MTA and PRF has a synergistic effect on the stimulation of odontoblastic differentiation of HDPCs via the modulation of the BMP/Smad signaling pathway. Copyright © 2016 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

Comparative evaluation of the isolation and quantification of stem cells derived from dental pulp and periodontal ligament of a permanent tooth and to assess their viability and proliferation on a platelet-rich fibrin scaffold.

PubMed

Khurana, Rohit; Kudva, Praveen Bhasker; Husain, Syed Yawer

2017-01-01

The present study aims to comparatively evaluate the isolation and quantification of stem cells derived from dental pulp and periodontal ligament of a permanent tooth and to assess their viability and proliferation on a platelet-rich fibrin (PRF) scaffold. A total of 15 systemically healthy individuals between the age group of 15-25 years requiring third molar or orthodontic premolar extractions. Teeth were extracted atraumatically and transported to the laboratory. Stem cells were isolated from dental pulp and periodontal ligament. After attaining more than 90% confluency by the 7 th day, these cells were tested for their viability and characterization. Stem cells were also incubated with PRF and viability was assessed on the 7 th day. The mean number of cell for dental pulp stem cells (DPSCs) and periodontal ligament stem cell (PDLSC) was statistically insignificant ( P > 0.05). The mean live cell viability was compared between DPSC (98.07%) and PDLSC (98%). Both DPSC and PDLSC showed a high percentage of expression of CD73 markers, 30.40% and 29.80%, respectively. However, DPSCs and PDLSCs lacked expression of CD34 expressing only 3.47% and 3.53%, respectively. PRF membrane as a scaffold exhibited no cytotoxic effects on DPCS's or PDLSC's. The cell viability of cells cultured with PRF was statistically insignificant ( P > 0.05) when compared to the cells cultured with culture media. The study thus indicates that dental pulp and periodontal ligament are both rich sources of mesenchymal stem cells and can be successfully used for obtaining stem cells. PRF exhibits no cytotoxic effects on the cells and can be used in conjunction with dental stem cells.

Medical Records Flag for Suicide Risk: Predictors and Subsequent Use of Care Among Veterans With Substance Use Disorders.

PubMed

Berg, Joanna M; Malte, Carol A; Reger, Mark A; Hawkins, Eric J

2018-06-08

The U.S. Department of Veterans Affairs (VA) health care system established policies to include patient record flags (PRFs) for high suicide risk in the electronic medical record to alert providers and to increase health care contacts. This study identified predictors of new PRFs and described health care utilization before and after PRF initiation among VA patients with substance use disorders. The sample included patients ages ≥18 who received a substance use disorder diagnosis in 2012 (N=474,946). Demographic, clinical, and utilization predictors of PRFs were identified by multivariable logistic regression. Changes in short-term (three months) and longer-term (12 months) health care utilization before and after PRF initiation were compared by negative binomial regression. A total of 8,913 patients received PRFs. Demographic predictors of PRF initiation included being younger than 35, white, and homeless. Clinical predictors were cocaine, opioid, and sedative use disorders; posttraumatic stress, psychotic, bipolar, and depressive disorders; and diagnosis of a suicide attempt. Patients with PRFs averaged 1.33 (95% confidence interval [CI]=1.29-1.38) times more primary care visits, 2.29 (CI=2.24-2.34) times more mental health visits, 4.10 (CI=3.80-4.42) times more substance use visits, and fewer (incidence rate ratio=.55, CI=.53-.58) emergency department visits in the three months following compared with the three months before PRF initiation. Modest increases in mental health- and substance use--related days hospitalized were observed. Veterans received significantly more health care services after PRF initiation. Further research is warranted on the effects of PRFs on clinical outcomes, such as suicide behaviors.

Investigation of Specific Substitutions in Virulence Genes Characterizing Phenotypic Groups of Low-Virulence Field Strains of Listeria monocytogenes

PubMed Central

Roche, S. M.; Gracieux, P.; Milohanic, E.; Albert, I.; Virlogeux-Payant, I.; Témoin, S.; Grépinet, O.; Kerouanton, A.; Jacquet, C.; Cossart, P.; Velge, P.

2005-01-01

Several models have shown that virulence varies from one strain of Listeria monocytogenes to another, but little is known about the cause of low virulence. Twenty-six field L. monocytogenes strains were shown to be of low virulence in a plaque-forming assay and in a subcutaneous inoculation test in mice. Using the results of cell infection assays and phospholipase activities, the low-virulence strains were assigned to one of four groups by cluster analysis and then virulence-related genes were sequenced. Group I included 11 strains that did not enter cells and had no phospholipase activity. These strains exhibited a mutated PrfA; eight strains had a single amino acid substitution, PrfAK220T, and the other three had a truncated PrfA, PrfAΔ174-237. These genetic modifications could explain the low virulence of group I strains, since mutated PrfA proteins were inactive. Group II and III strains entered cells but did not form plaques. Group II strains had low phosphatidylcholine phospholipase C activity, whereas group III strains had low phosphatidylinositol phospholipase C activity. Several substitutions were observed for five out of six group III strains in the plcA gene and for one out of three group II strains in the plcB gene. Group IV strains poorly colonized spleens of mice and were practically indistinguishable from fully virulent strains on the basis of the above-mentioned in vitro criteria. These results demonstrate a relationship between the phenotypic classification and the genotypic modifications for at least group I and III strains and suggest a common evolution of these strains within a group. PMID:16204519

Comparison of Widely Used Listeria monocytogenes Strains EGD, 10403S, and EGD-e Highlights Genomic Differences Underlying Variations in Pathogenicity

PubMed Central

Bécavin, Christophe; Bouchier, Christiane; Lechat, Pierre; Archambaud, Cristel; Creno, Sophie; Gouin, Edith; Wu, Zongfu; Kühbacher, Andreas; Brisse, Sylvain; Pucciarelli, M. Graciela; García-del Portillo, Francisco; Hain, Torsten; Portnoy, Daniel A.; Chakraborty, Trinad; Lecuit, Marc; Pizarro-Cerdá, Javier; Moszer, Ivan; Bierne, Hélène; Cossart, Pascale

2014-01-01

ABSTRACT For nearly 3 decades, listeriologists and immunologists have used mainly three strains of the same serovar (1/2a) to analyze the virulence of the bacterial pathogen Listeria monocytogenes. The genomes of two of these strains, EGD-e and 10403S, were released in 2001 and 2008, respectively. Here we report the genome sequence of the third reference strain, EGD, and extensive genomic and phenotypic comparisons of the three strains. Strikingly, EGD-e is genetically highly distinct from EGD (29,016 single nucleotide polymorphisms [SNPs]) and 10403S (30,296 SNPs), and is more related to serovar 1/2c than 1/2a strains. We also found that while EGD and 10403S strains are genetically very close (317 SNPs), EGD has a point mutation in the transcriptional regulator PrfA (PrfA*), leading to constitutive expression of several major virulence genes. We generated an EGD-e PrfA* mutant and showed that EGD behaves like this strain in vitro, with slower growth in broth and higher invasiveness in human cells than those of EGD-e and 10403S. In contrast, bacterial counts in blood, liver, and spleen during infection in mice revealed that EGD and 10403S are less virulent than EGD-e, which is itself less virulent than EGD-e PrfA*. Thus, constitutive expression of PrfA-regulated virulence genes does not appear to provide a significant advantage to the EGD strain during infection in vivo, highlighting the fact that in vitro invasion assays are not sufficient for evaluating the pathogenic potential of L. monocytogenes strains. Together, our results pave the way for deciphering unexplained differences or discrepancies in experiments using different L. monocytogenes strains. PMID:24667708

Efficacy of platelet rich fibrin in the treatment of human intrabony defects with or without bone graft: A randomized controlled trial

PubMed Central

Chandradas, Nikhil D.; Ravindra, Shivamurthy; Rangaraju, Vivekananda M.; Jain, Sheetal; Dasappa, Shivaprasad

2016-01-01

Aim: To evaluate the efficacy of platelet rich fibrin (PRF) with or without bone graft [demineralized bone matrix (DBM) graft] in the treatment of intrabony defects based on clinical and radiographic parameters. Materials and Methods: Thirty six intrabony defects in 36 patients were randomly divided into three different groups and were treated with group A (PRF with DBM) or group B (PRF alone) or group C [open flap debridement (OFD)]. Clinical parameters such as plaque index (PI), gingival index (GI), probing depth (PD), relative attachment level (RAL), and gingival recession (GR) were assessed at baseline and 9 months postoperatively; radiographic parameters such as linear bone growth (LBG) and percentage in bone fill (%BF) were calculated by using the image analysis software. Comparisons of groups were analyzed using Kruskal–Wallis analysis of variance test. Pair-wise comparison of groups was done by Mann-Whitney U test. Results: Mean PD reduction and RAL gain were greater in group A (4.25 ± 1.48, 3.92 ± 0.90) and group B (3.82 ± 0.75, 3.27 ± 0.65) than control (3.00 ± 1.21, 2.25 ± 0.62). Furthermore, statistically significant improvement in LBG and %BF was found in group A (3.47 ± 0.53, 61.53 ± 4.54) compared to group B (2.55 ± 0.61, 49.60 ± 14.08) and group C (1.21 ± 0.80, 24.69 ± 15.59). Conclusions: The study demonstrated that PRF improves clinical and radiological parameters compared to OFD alone in intrabony defects. Addition of DBM enhances the effects of PRF in RAL gain and radiographic defect fill. PMID:27652249

Revascularization Induced Maturogenesis of Non-Vital Immature Permanent Tooth Using Platelet-Rich-Fibrin: A Case Report.

PubMed

Nagaveni, N B; Pathak, Sidhant; Poornima, P; Joshi, Jooie S

2016-01-01

The aim of this report is to describe a novel method of revascularization therapy done in a non-vital, immature permanent tooth using Platelet-rich fibrin (PRF),in a recently developed scaffold material to overcome limitations associated with the traditional method of revascularization using natural blood clot. PRF prepared from autologous blood was placed in the root canal and patient was followed up regularly at one, three, six, nine and 12 months for detailed clinical and radiographic evaluation. At 12 months, radiographic examination revealed root elongation, root end closure, continued thickening of the root dentinal walls, obliteration of root canal space, and normal periradicular anatomy. However, more long term prospective trials and histological studies are highly needed before to testify PRF a panacea for the regenerative endodontic therapy in children.

Time stretch dispersive Fourier transform based single-shot pulse-by-pulse spectrum measurement using a pulse-repetition-frequency-variable gain-switched laser

NASA Astrophysics Data System (ADS)

Furukawa, Hideaki; Makino, Takeshi; Wang, Xiaomin; Kobayashi, Tetsuya; Asghari, Mohammad H.; Trinh, Paul; Jalali, Bahram; Man, Wai Sing; Tsang, Kwong Shing; Wada, Naoya

2018-02-01

The time stretch dispersive Fourier Transform (TS-DFT) technique based on a fiber chromatic dispersion is a powerful tool for pulse-by-pulse single-shot spectrum measurement for highrepetition rate optical pulses. The distributed feedback laser diode (DFB-LD) with the gain switch operation can flexibly change the pulse repetition frequency (PRF). In this paper, we newly introduce a semiconductor gain-switched DFB-LD operating from 1 MHz up to 1 GHz PRF into the TS-DFT based spectrum measurement system to improve the flexibility and the operability. The pulse width can be below 2 ps with a pulse compression technique. We successfully measure the spectrum of each optical pulse at 1 GHz, 100 MHz, and 10 MHz PRF, and demonstrate the flexibility of the measurement system.

Experimental proof of the existence of water clusters in fullerene-like PrF3 nanoparticles

NASA Astrophysics Data System (ADS)

Alakshin, E. M.; Blokhin, D. S.; Sabitova, A. M.; Klochkov, A. V.; Klochkov, V. V.; Kono, K.; Korableva, S. L.; Tagirov, M. S.

2012-10-01

Synthesized fullerene-like nanoparticles of the Van Vleck paramagnet PrF3 have been studied by nuclear magnetic resonance cryoporometry. Water clusters have been discovered in the internal cavities of the nanoparticles. The analysis of the experimental data indicates that the cluster radius is 1-2.3 nm. The obtained data agree well with the high-resolution transmission electron microscopy data.

Long-term follow up of revascularization using platelet-rich fibrin.

PubMed

Ray, Herbert L; Marcelino, Janel; Braga, Raquel; Horwat, Richard; Lisien, Michael; Khaliq, Shahryar

2016-02-01

Trauma is one of the primary causes of tooth loss and pulpal injury in adolescents and children. Prior to regenerative endodontics, treatment of necrotic, immature teeth with open apices was limited to long-term calcium hydroxide (Ca(OH)2 ) apexification and subsequent root canal therapy or extraction. Through revascularization, retention of these teeth can be achieved and the elimination of patient symptoms and the radiographic appearance of continued root development were obtained. This report illustrates a revascularization protocol through a case where platelet-rich fibrin (PRF) was utilized as an autologous scaffold for traumatized, necrotic, immature teeth with incomplete root development. Through consistent follow-up reports, comprising of both clinical examination and radiographs, marked improvement in the condition of the traumatized tooth was noted. This case demonstrates the feasibility of utilizing PRF as an effective treatment protocol for traumatized teeth in lieu of traditional treatment protocols, such as long-term calcium hydroxide (Ca(OH)2 ) apexification or extraction. The choice of utilizing PRF, as opposed to other platelet concentrates, such as platelet-rich plasma (PRP) or a blood clot, lies in PRF's ability to allow for a slow, long-term release of autologous growth factors. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Effect of Platelet-rich Fibrin on Healing of Apicomarginal Defects: A Randomized Controlled Trial.

PubMed

Dhiman, Meenu; Kumar, Suresh; Duhan, Jigyasa; Sangwan, Pankaj; Tewari, Sanjay

2015-07-01

The purpose of this prospective, randomized controlled trial was to evaluate the healing outcomes of platelet-rich fibrin (PRF) in periapical surgeries involving apicomarginal defects and to compare these results with surgeries not using any guided tissue regeneration techniques. Thirty patients with suppurative chronic apical periodontitis and apicomarginal communication were randomly assigned to either the PRF or the control group. Clinical and radiographic parameters including pocket depth (PD), clinical attachment level, gingival marginal position, size of periapical lesion, and percentage reduction of the periapical radiolucency were recorded at baseline and at an interval of 3 months for a period of 12 months. The overall success rate was 83.33%, with a success rate of 86.66% (13 of 15 teeth) for PRF group and 80% (12 of 15 teeth) for control group. Both the groups exhibited a significant reduction in PD, clinical attachment level, gingival marginal position, and size of periapical lesion at 12-month period. No significant differences were observed between the 2 groups for these parameters except PD, which showed a statistically significant reduction in the PRF group (P < .05). The adjunctive use of regenerative techniques may not promote healing of apicomarginal defects of endodontic origin. Copyright © 2015 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

Use of a platelet-rich fibrin membrane to repair traumatic tympanic membrane perforations: a comparative study.

PubMed

Gür, Özer Erdem; Ensari, Nuray; Öztürk, Mehmet Türker; Boztepe, Osman Fatih; Gün, Taylan; Selçuk, Ömer Tarık; Renda, Levent

2016-10-01

(1) To evaluate the effects of a platelet-rich fibrin (PRF) membrane in the repair of traumatic tympanic membrane (TM) perforations; and (2) to compare the use of a PRF membrane with the paper patch technique with regard to recovery rates, healing time, and correction of the mean air-bone gap. A randomized, prospective analysis was performed for 60 patients who were treated for traumatic TM perforations using one of the two methods. Closure rate, speed of healing, and hearing gain were compared between the PRF (Group 1) and paper patch (Group 2) groups. Closure was obtained in 28 (93%) perforations in Group 1 and 25 (83%) perforations in Group 2 (p > 0.05). On day 10, full closure of the TM was observed in 24 (80%) patients in Group 1 and 16 (53%) patients in Group 2 (p < 0.05). The improvement in the mean air-bone gap was 14.1 dB in Group 1 and 12.4 dB in Group 2 on post-operative day 45 (p < 0.05). In comparison with the paper patch method, PRF, a new method, provided more rapid healing with more successful audiological results, and with no requirement for a second procedure.

Single-Tooth Osteotomy Combined Wide Linear Corticotomy Under Local Anesthesia for Correcting Anterior Protrusion With Ectopically Erupted Canine.

PubMed

Iskenderoglu, Nur Serife; Choi, Byung-Joon; Seo, Kyung Won; Lee, Yeon-Ji; Lee, Baek-Soo; Kim, Seong-Hun

2017-01-01

This article presents the alternative surgical treatments of both anterior protrusion by carrying out retraction on mandibular anterior fragment, meanwhile applying retraction force on maxilla anterior teeth and ectopically erupted canine with using platelet-rich fibrin (PRF). Anterior segmental osteotomy was combined with linear corticotomy under local anesthesia. The correction of right ectopic canine was achieved through 2 stages. First, dento-osseous osteotomy on palatal side was performed. Then second osteotomy with immediate manual repositioning of the canine with concomitant first premolar extraction was enhanced with PRF, which was prepared by centrifuging patient's blood, applied into buccal side of high canine during osteotomy. Mandibular retraction was accomplished by anterior segmental osteotomy. Single-tooth osteotomy is a more effective surgical method for ankylosed or ectopically erupted tooth in orthodontic treatment. It can reduce the total orthodontic treatment time and root resorption, 1 common complication. Significant improved bone formation was seen with the addition of PRF on noncritical size defects in the animal model. It is reasonable to think that PRF can promote bone regeneration. So early bone formation also can reduce the complication such as postoperative infection. As an alternative to anterior protrusion and ectopically erupted canine treatment, segmental osteotomy and corticotomy combined platelet-rich plasma can enhance orthodontic treatment outcome.

Evolution, current status and advances in application of platelet concentrate in periodontics and implantology

PubMed Central

Agrawal, Amit Arvind

2017-01-01

Platelet concentrates (PC) [platelet-rich plasma (PRP) and platelet-rich fibrin (PRF)] are frequently used for surgical procedures in medical and dental fields, particularly in oral and maxillofacial surgery, plastic surgery and sports medicine. The objective of all these technologies is to extract all the elements from a blood sample that could be used to improve healing and promote tissue regeneration. Although leukocyte rich and leukocyte poor PRP’s have their own place in literature, the importance of non-platelet components in a platelet concentrate remains a mystery. PC have come a long way since its first appearance in 1954 to the T-PRF, A-PRF and i-PRF introduced recently. These PC find varied applications successfully in periodontics and implant dentistry as well. However, the technique of preparation, standing time, transfer process, temperature of centrifuge, vibration, etc., are the various factors for the mixed results reported in the literature. Until the introduction of a proper classification of terminologies, the PC were known by different names in different countries and by different commercial companies which also created a lot of confusion. This review intends to clarify all these confusion by briefing the exact evolution of PC, their preparation techniques, recent advances and their various clinical and technical aspects and applications. PMID:28560233

Technique for long and absolute distance measurement based on laser pulse repetition frequency sweeping

NASA Astrophysics Data System (ADS)

Castro Alves, D.; Abreu, Manuel; Cabral, A.; Jost, Michael; Rebordão, J. M.

2017-11-01

In this work we present a technique to perform long and absolute distance measurements based on mode-locked diode lasers. Using a Michelson interferometer, it is possible to produce an optical cross-correlation between laser pulses of the reference arm with the pulses from the measurement arm, adjusting externally their degree of overlap either changing the pulse repetition frequency (PRF) or the position of the reference arm mirror for two (or more) fixed frequencies. The correlation of the travelling pulses for precision distance measurements relies on ultra-short pulse durations, as the uncertainty associated to the method is dependent on the laser pulse width as well as on a highly stable PRF. Mode-locked Diode lasers are a very appealing technology for its inherent characteristics, associated to compactness, size and efficiency, constituting a positive trade-off with regard to other mode-locked laser sources. Nevertheless, main current drawback is the non-availability of frequency-stable laser diodes. The laser used is a monolithic mode-locked semiconductor quantum-dot (QD) laser. The laser PRF is locked to an external stabilized RF reference. In this work we will present some of the preliminary results and discuss the importance of the requirements related to laser PRF stability in the final metrology system accuracy.

Strategies Low-Income Parents Use to Overcome Their Children's Food Refusal.

PubMed

Goodell, L Suzanne; Johnson, Susan L; Antono, Amanda C; Power, Thomas G; Hughes, Sheryl O

2017-01-01

Introduction Parents play a key role in the development of eating habits in preschool children, as they are the food "gatekeepers." Repeated exposure to new foods can improve child food preferences and consumption. The objective of this study was to determine parent feeding strategies used to influence child acceptance of previously rejected foods (PRF). Methods We conducted eighteen focus groups (total participants = 111) with low-income African American and Hispanic parents of preschool children (3- to 5-year-olds) in Texas, Colorado, and Washington. Through thematic analysis, we coded transcripts and analyzed coded quotes to develop dominant emergent themes related to strategies used to overcome children's food refusal. Results We found three major themes in the data: parents most often do not serve PRF; parents value their child eating over liking a food; and parents rarely use the same feeding strategy more than once for a PRF. Desiring to reduce waste and save time, parents said they most often intentionally decided not to purchase or serve PRF to their children. Discussion Because parents' primary goal in child feeding is getting children to eat (over acceptance of a variety of foods), strategies to help parents promote consumption of less easily accepted foods could help parents with child feeding struggles and improve children's dietary quality.

Clinical effectiveness of combining platelet rich fibrin with alloplastic bone substitute for the management of combined endodontic periodontal lesion

PubMed Central

2014-01-01

The term "endo-perio" lesion has been proposed to describe the destructive lesion resulting from inflammatory products found in varying degrees in both the periodontium and the pulpal tissues. In most of the cases, clinical symptoms disappear following successful endodontic therapy. However failure after conventional root canal treatment calls for surgical intervention. A 35 year old male patient with endo-perio lesion in right maxillary lateral incisor was treated with platelet rich fibrin (PRF) and alloplastic bone substitute after conventional endodontic therapy. At the end of 6 months there was gain in clinical attachment, increased radiographic bone fill and reduction in probing depth which was maintained till 18 month follow-up. Present case report aims to evaluate the efficacy of PRF and alloplastic bone substitute in the management of intrabony defect associated with endo-perio lesion in maxillary lateral incisor because the healing potential of PRF and bone graft has not been widely studied in endodontics. The use of PRF allows the clinician to optimize tissue remodelling, wound healing and angiogenesis by the local delivery of growth factors and proteins. The novel technique described here enables the clinician to be benefited from the full regenerative capacity of this autologous biologic material. PMID:24516830

Clinical effectiveness of combining platelet rich fibrin with alloplastic bone substitute for the management of combined endodontic periodontal lesion.

PubMed

Goyal, Lata

2014-02-01

The term "endo-perio" lesion has been proposed to describe the destructive lesion resulting from inflammatory products found in varying degrees in both the periodontium and the pulpal tissues. In most of the cases, clinical symptoms disappear following successful endodontic therapy. However failure after conventional root canal treatment calls for surgical intervention. A 35 year old male patient with endo-perio lesion in right maxillary lateral incisor was treated with platelet rich fibrin (PRF) and alloplastic bone substitute after conventional endodontic therapy. At the end of 6 months there was gain in clinical attachment, increased radiographic bone fill and reduction in probing depth which was maintained till 18 month follow-up. Present case report aims to evaluate the efficacy of PRF and alloplastic bone substitute in the management of intrabony defect associated with endo-perio lesion in maxillary lateral incisor because the healing potential of PRF and bone graft has not been widely studied in endodontics. The use of PRF allows the clinician to optimize tissue remodelling, wound healing and angiogenesis by the local delivery of growth factors and proteins. The novel technique described here enables the clinician to be benefited from the full regenerative capacity of this autologous biologic material.

REM sleep enhancement and behavioral cataplexy following orexin (hypocretin)-II receptor antisense perfusion in the pontine reticular formation.

PubMed

Thakkar, M M; Ramesh, V; Cape, E G; Winston, S; Strecker, R E; McCarley, R W

1999-01-01

Orexin (hypocretin)-containing neurons of the hypothalamus project to brainstem sites that are involved in the neural control of REM sleep, including the locus coeruleus, the dorsal raphe nucleus, the cholinergic zone of the mesopontine tegmentum, and the pontine reticular formation (PRF). Orexin knockout mice exhibit narcolepsy/cataplexy, and a mutant and defective gene for the orexin type II receptor is present in dogs with an inherited form of narcolepsy/cataplexy. However, the physiological systems mediating these effects have not been described. We reasoned that, since the effector neurons for the majority of REM sleep signs, including muscle atonia, were located in the PRF, this region was likely implicated in the production of these orexin-related abnormalities. To test this possibility, we used microdialysis perfusion of orexin type II receptor antisense in the PRF of rats. Ten to 24 hours after antisense perfusion, REM sleep increased two- to three-fold during both the light period (quiescent phase) and the dark period (active phase), and infrared video showed episodes of behavioral cataplexy. Moreover, preliminary data indicated no REM-related effects following perfusion with nonsense DNA, or when perfusion sites were outside the PRF. More work is needed to provide precise localization of the most effective site of orexin-induced inhibition of REM sleep phenomena.

The use of platelet-rich fibrin combined with periodontal ligament and jaw bone mesenchymal stem cell sheets for periodontal tissue engineering.

PubMed

Wang, Zhong-Shan; Feng, Zhi-Hong; Wu, Guo-Feng; Bai, Shi-Zhu; Dong, Yan; Chen, Fa-Ming; Zhao, Yi-Min

2016-06-21

Periodontal regeneration involves the restoration of at least three unique tissues: cementum, periodontal ligament tissue (PDL) and alveolar bone tissue. Here, we first isolated human PDL stem cells (PDLSCs) and jaw bone mesenchymal stem cells (JBMSCs). These cells were then induced to form cell sheets using an ascorbic acid-rich approach, and the cell sheet properties, including morphology, thickness and gene expression profile, were compared. Platelet-rich fibrin (PRF) derived from human venous blood was then fabricated into bioabsorbable fibrin scaffolds containing various growth factors. Finally, the in vivo potential of a cell-material construct based on PDLSC sheets, PRF scaffolds and JBMSC sheets to form periodontal tissue was assessed in a nude mouse model. In this model, PDLSC sheet/PRF/JBMSC sheet composites were placed in a simulated periodontal space comprising human treated dentin matrix (TDM) and hydroxyapatite (HA)/tricalcium phosphate (TCP) frameworks. Eight weeks after implantation, the PDLSC sheets tended to develop into PDL-like tissues, while the JBMSC sheets tended to produce predominantly bone-like tissues. In addition, the PDLSC sheet/PRF/JBMSC sheet composites generated periodontal tissue-like structures containing PDL- and bone-like tissues. Further improvements in this cell transplantation design may have the potential to provide an effective approach for future periodontal tissue regeneration.

Evolution, current status and advances in application of platelet concentrate in periodontics and implantology.

PubMed

Agrawal, Amit Arvind

2017-05-16

Platelet concentrates (PC) [platelet-rich plasma (PRP) and platelet-rich fibrin (PRF)] are frequently used for surgical procedures in medical and dental fields, particularly in oral and maxillofacial surgery, plastic surgery and sports medicine. The objective of all these technologies is to extract all the elements from a blood sample that could be used to improve healing and promote tissue regeneration. Although leukocyte rich and leukocyte poor PRP's have their own place in literature, the importance of non-platelet components in a platelet concentrate remains a mystery. PC have come a long way since its first appearance in 1954 to the T-PRF, A-PRF and i-PRF introduced recently. These PC find varied applications successfully in periodontics and implant dentistry as well. However, the technique of preparation, standing time, transfer process, temperature of centrifuge, vibration, etc ., are the various factors for the mixed results reported in the literature. Until the introduction of a proper classification of terminologies, the PC were known by different names in different countries and by different commercial companies which also created a lot of confusion. This review intends to clarify all these confusion by briefing the exact evolution of PC, their preparation techniques, recent advances and their various clinical and technical aspects and applications.

Attention-deficit/hyperactivity disorder Under Treatment Outcomes Research (AUTOR): a European observational study in pediatric subjects.

PubMed

Haynes, Virginia; Lopez-Romero, Pedro; Anand, Ernie

2015-12-01

The ADHD Under Treatment Observational Research (AUTOR) study was a European prospective, observational study that assessed factors associated with changes in ADHD severity, estimated change from baseline in quality of life (QoL), and characterized changes in ADHD symptoms over a 2-year period as a function of baseline treatment. The primary objective was to identify factors associated with worsening in ADHD severity during a 2-year follow-up period for subjects aged 6-17 years, who were receiving the same pharmacotherapy for 3-8 months before enrollment and had a Clinical Global Impression (CGI)-ADHD-Severity score of mild/lower and a CGI-ADHD-Improvement score of improved/very much improved. Multivariate logistic regression examined the association of factors with worsening in ADHD. Mixed-model repeated measures regression analyzed QoL in terms of change from baseline in CHIP-CE PRF scores. There were 704 subjects analyzed. Variables associated with worsening ADHD severity were parental occupation, poorer school outcomes, and use of psychoeducation; baseline treatment was not significant. Among the secondary objectives, initial use of atomoxetine (vs. stimulants) was associated with a significant improvement on the CHIP-CE PRF total score, with an adjusted treatment difference of -6.0 (95 % CI -7.9, -4.1) at 24 months. Additionally, the odds of stability (CGI-ADHD-S ≤ 3 over the 2-year period) were significantly lower for subjects initially responding to stimulants compared with atomoxetine (OR 0.5; 95 % CI 0.3, 0.8). ADHD symptom worsening was associated with initial use of psychoeducation, parental occupation, and poorer school outcomes. Response to initial treatment with atomoxetine was associated with improved QoL over 2 years.

Health-related quality of life and functional outcomes from a randomized-withdrawal study of long-term lisdexamfetamine dimesylate treatment in children and adolescents with attention-deficit/hyperactivity disorder.

PubMed

Banaschewski, Tobias; Johnson, Mats; Lecendreux, Michel; Zuddas, Alessandro; Adeyi, Ben; Hodgkins, Paul; Squires, Liza A; Coghill, David R

2014-12-01

The stimulant prodrug lisdexamfetamine dimesylate (LDX) is an effective and generally well tolerated treatment for the symptoms of attention-deficit/hyperactivity disorder (ADHD). Positive impacts of LDX on health-related quality of life and functional impairment have previously been demonstrated in a 7-week, randomized, double-blind, placebo-controlled, phase III study in children and adolescents in Europe. Maintenance of these broad benefits, as well as symptomatic control, is a key goal of long-term management of ADHD. Secondary objectives of this multinational study in children and adolescents with ADHD were to assess the long-term maintenance of effectiveness of LDX in improving health-related quality of life and reducing functional impairment, as gauged using the Child Health and Illness Profile-Child Edition: Parent Report Form (CHIP-CE: PRF) and the Weiss Functional Impairment Rating Scale-Parent Report (WFIRS-P), respectively. Patients aged 6-17 years with diagnosed ADHD and a baseline ADHD Rating Scale IV total score of at least 28 were enrolled from the previous European study and from US sites. Patients who completed an open-label LDX treatment period of at least 26 weeks were randomized (1:1) to continue on their optimized dose of LDX or to switch to placebo for a 6-week, double-blind, withdrawal period. Parents completed CHIP-CE: PRF and WFIRS-P questionnaires at weeks 0, 8 and 26 of the open-label period and at weeks 0 and 6 of the randomized-withdrawal period, or at early termination. The endpoint of each period was defined as the last visit with valid data. Effect sizes were the difference (LDX minus placebo) in least-squares (LS)-mean change from baseline to endpoint divided by root-mean-square error. P values were nominal and not adjusted for multiple comparisons. The open-label and randomized full analysis sets comprised 262 and 153 (LDX n = 76; placebo n = 77) patients, respectively. Mean pretreatment CHIP-CE: PRF T-scores were more than one standard deviation below the normative mean in four of the five domains, and there was significant improvement across all domains from baseline to endpoint of the open-label period. In the randomized-withdrawal period, LS-mean CHIP-CE: PRF T-scores deteriorated in all domains in the placebo group, but not in the LDX group. Compared with placebo, the effect of LDX was significant in the Risk Avoidance (effect size 0.829; p < 0.001), Achievement (0.696; p < 0.001) and Satisfaction (0.636; p < 0.001) domains. Mean pretreatment WFIRS-P scores were lowest in the Family domain and the Learning and School domain. WFIRS-P total score and scores in all domains improved significantly from baseline to endpoint of the open-label period. In the randomized-withdrawal period, LS-mean scores deteriorated in the placebo group but not in the LDX group. Compared with placebo, the effect of LDX was significant in the Family, Learning and School, and Risky Activities domains and in total (effect size 0.908; p < 0.001). Using parent-rated instruments, long-term maintenance of the beneficial effect of LDX in multiple domains of health-related quality of life and functional impairment was demonstrated by comparison of treatment continuation and withdrawal under randomized, double-blind, placebo-controlled conditions.

Aviation Requirements for Use of Recycled MIL-PRF-680

DTIC Science & Technology

2012-05-24

components – Approximately 1,000 gallons of virgin MIL-PRF-680 Type II used and disposed every 6 months at Fort Rucker Calculated using the full...capacity of the parts washers – Recycling will reduce the need to purchase virgin solvent and reduce disposal costs – Expressed interest received...with virgin solvent Clarus PCS-25 Parts Washer Clarus Tornado Filtration System INSERT EVENT TITLE – INSERT MONTH & YEAR Aviation Requirements for Use

Management of an endo-perio lesion in an immature tooth using autologous platelet-rich fibrin: a case report.

PubMed

Nagaveni, N B; Kumari, K Nandini; Poornima, P; Reddy, V V Subba

2015-01-01

Treatment of an endo-perio lesion involving a non-vital young permanent tooth is a highly challenging task to Pediatric Dentists. There is a quest for the newer biological approach to management of these lesions as traditional methods have various disadvantages. Recently, platelet-rich fibrin (PRF), a second-generation platelet concentrate, is rich in growth factors have been used in the periodontal regeneration procedure. The purpose of this paper is to describe the efficacy of PRF in the treatment of a deep intra bony defect associated with an endo-perio lesion in an immature right mandibular first premolar of 12-year-old female patient. A freshly prepared autologous PRF membrane was placed in the bony defect following debridement. Clinical and radiographic follow-up were performed at regular intervals that revealed absence of pain, gain in clinical attachment level, reduction in probing depth, and excellent bone regeneration indicating successful outcome.

Late-onset severe chronic active EBV in a patient for five years with mutations in STXBP2 (MUNC18-2) and PRF1 (perforin 1).

PubMed

Cohen, Jeffrey I; Niemela, Julie E; Stoddard, Jennifer L; Pittaluga, Stefania; Heslop, Helen; Jaffe, Elaine S; Dowdell, Kennichi

2015-07-01

Severe chronic active Epstein-Barr virus (CAEBV) disease is defined as a severe progressive illness lasting 6 months or longer with infiltration of tissues with EBV-positive lymphocytes, markedly elevated levels of EBV DNA in the blood, and no known immunodeficiency such as HIV. These patients usually have fever, splenomegaly, lymphadenopathy, and may have markedly elevated EBV antibody titers to viral capsid antigen. Although the cause of most cases of severe CAEBV is unknown, one well-documented case was associated with compound heterozygous mutations in PRF1 (perforin 1). Here we report a patient with prolonged severe CAEBV who underwent bone marrow transplant for his disease and subsequently was found to have compound heterozygous mutations in STXBP2 (MUNC18-2) as well as a heterozygous mutation in PRF1 (perforin 1).

Late-onset Severe Chronic Active EBV in a Patient for Five Years with Mutations in STXBP2 (MUNC18-2) and PRF1 (Perforin 1)

PubMed Central

Cohen, Jeffrey I.; Niemela, Julie E.; Stoddard, Jennifer L.; Pittaluga, Stefania; Heslop, Helen; Jaffe, Elaine S.; Dowdell, Kennichi

2015-01-01

Severe chronic active Epstein-Barr virus (CAEBV) disease is defined as a severe progressive illness lasting 6 months or longer with infiltration of tissues with EBV-positive lymphocytes, markedly elevated levels of EBV DNA in the blood, and no known immunodeficiency such as HIV. These patients usually have fever, splenomegaly, lymphadenopathy, and may have markedly elevated EBV antibody titers to viral capsid antigen. Although the cause of most cases of severe CAEBV is unknown, one well-documented case was associated with compound heterozygous mutations in PRF1 (perforin 1). Here we report a patient with prolonged severe CAEBV who underwent bone marrow transplant for his disease and subsequently was found to have compound heterozygous mutations in STXBP2 (MUNC18-2) as well as a heterozygous mutation in PRF1 (perforin 1). PMID:25947952

Direct implantation versus platelet-rich fibrin-embedded adipose-derived mesenchymal stem cells in treating rat acute myocardial infarction.

PubMed

Sun, Cheuk-Kwan; Zhen, Yen-Yi; Leu, Steve; Tsai, Tzu-Hsien; Chang, Li-Teh; Sheu, Jiunn-Jye; Chen, Yung-Lung; Chua, Sarah; Chai, Han-Tan; Lu, Hung-I; Chang, Hsueh-Wen; Lee, Fan-Yen; Yip, Hon-Kan

2014-05-15

This study tested whether adipose-derived mesenchymal stem cells (ADMSC) embedded in platelet-rich fibrin (PRF) scaffold is superior to direct ADMSC implantation in improving left ventricular (LV) performance and reducing LV remodeling in a rat acute myocardial infarction (AMI) model of left anterior descending coronary artery (LAD) ligation. Twenty-eight male adult Sprague Dawley rats equally divided into group 1 [sham control], group 2 (AMI only), group 3 (AMI+direct ADMSC implantation), and group 4 (AMI+PRF-embedded autologous ADMSC) were sacrificed on day 42 after AMI. LV systolic and diastolic dimensions and volumes, and infarct/fibrotic areas were highest in group 2, lowest in group 1 and significantly higher in group 3 than in group 4, whereas LV performance and LV fractional shortening exhibited a reversed pattern (p<0.005). Protein expressions of inflammation (oxidative stress, IL-1β, MMP-9), apoptosis (mitochondrial Bax, cleaved PARP), fibrosis (Smad3, TGF-β), and pressure-overload biomarkers (BNP, MHC-β) displayed a pattern similar to that of LV dimensions, whereas anti-inflammatory (IL-10), anti-apoptotic (Bcl-2), and anti-fibrotic (Smad1/5, BMP-2) indices showed a pattern similar to that of LV performance among the four groups (all p<0.05). Angiogenesis biomarkers at protein (CXCR4, SDF-1α, VEGF), cellular (CD31+, CXCR4+, SDF-1α+), and immunohistochemical (small vessels) levels, and cardiac stem cell markers (C-kit+, Sca-1+) in infarct myocardium were highest in group 4, lowest in group 1, and significantly higher in group 3 than in group 2 (all p<0.005). PRF-embedded ADMSC is superior to direct ADMSC implantation in preserving LV function and attenuating LV remodeling. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

Dose-specific transcriptional responses in thyroid tissue in mice after (131)I administration.

PubMed

Rudqvist, Nils; Schüler, Emil; Parris, Toshima Z; Langen, Britta; Helou, Khalil; Forssell-Aronsson, Eva

2015-03-01

In the present investigation, microarray analysis was used to monitor transcriptional activity in thyroids in mice 24 h after (131)I exposure. The aims of this study were to 1) assess the transcriptional patterns associated with (131)I exposure in normal mouse thyroid tissue and 2) propose biomarkers for (131)I exposure of the thyroid. Adult BALB/c nude mice were i.v. injected with 13, 130 or 260 kBq of (131)I and killed 24h after injection (absorbed dose to thyroid: 0.85, 8.5, or 17 Gy). Mock-treated mice were used as controls. Total RNA was extracted from thyroids and processed using the Illumina platform. In total, 497, 546, and 90 transcripts were regulated (fold change ≥1.5) in the thyroid after 0.85, 8.5, and 17 Gy, respectively. These were involved in several biological functions, e.g. oxygen access, inflammation and immune response, and apoptosis/anti-apoptosis. Approximately 50% of the involved transcripts at each absorbed dose level were dose-specific, and 18 transcripts were commonly detected at all absorbed dose levels. The Agpat9, Plau, Prf1, and S100a8 gene expression displayed a monotone decrease in regulation with absorbed dose, and further studies need to be performed to evaluate if they may be useful as dose-related biomarkers for 131I exposure. Distinct and substantial differences in gene expression and affected biological functions were detected at the different absorbed dose levels. The transcriptional profiles were specific for the different absorbed dose levels. We propose that the Agpat9, Plau, Prf1, and S100a8 genes might be novel potential absorbed dose-related biomarkers to (131)I exposure of thyroid. During the recent years, genomic techniques have been developed; however, they have not been fully utilized in nuclear medicine and radiation biology. We have used RNA microarrays to investigate genome-wide transcriptional regulations in thyroid tissue in mice after low, intermediate, and high absorbed doses from (131)I exposure in vivo. Using this approach, we have identified novel biological responses and potential absorbed dose-related biomarkers to (131)I exposure. Our research shows the importance of embracing technological advances and multi-disciplinary collaboration in order to apply them in radiation therapy, nuclear medicine, and radiation biology. This work may contribute with new knowledge of potential normal tissue effects or complications that may occur after exposure to ionizing radiation in diagnostic and therapeutic nuclear medicine, and due to radioactive fallout or accident with radionuclide spread. Copyright © 2014 Elsevier Inc. All rights reserved.

Variations of bubble cavitation and temperature elevation during lesion formation by high-intensity focused ultrasound.

PubMed

Zhou, Yufeng; Gao, Xiaobin Wilson

2013-08-01

High-intensity focused ultrasound (HIFU) is emerging as an effective therapeutic modality in both thermal ablations for solid tumor/cancer and soft-tissue fragmentation. Mechanical and thermal effects, which play an important role in the HIFU treatment simultaneously, are dependent on the operating parameters and may vary with the progress of therapy. Mechanical erosion in the shape of a "squid," a "dumbbell" lesion with both mechanical and thermal lesions, or a "tadpole" lesion with mechanical erosion at the center and thermal necrosis on the boundary in the transparent gel phantom could be produced correspondingly with the pulse duration of 5-30 ms, which is much longer than histotripsy burst but shorter than the time for tissue boiling, and pulse repetition frequency (PRF) of 0.2-5 Hz. Meanwhile, variations of bubble cavitation (both inertial and stable cavitation) and temperature elevation in the focal region (i.e., z = -2.5, 0, and 2.5 mm) were measured by passive cavitation detection (PCD) and thermocouples during the therapeutic procedure, respectively. Stable cavitation increased with the pulse duration, PRF, and the number of pulses delivered. However, inertial cavitation was found to increase initially and then decrease with long pulse duration and high PRF. Temperature in the pre-focal region is always higher than those at the focal and post-focal position in all tests. Great variations of PCD signals and temperature elevation are due to the generation and persistence of large bubble, which is resistant to collapse and occurs with the increase of pulse duration and PRF. Similar lesion pattern and variations were also observed in ex vivo porcine kidneys. Hyperechoes in the B-mode ultrasound image were comparable to the shape and size of lesions in the dissected tissue. Thermal lesion volume increased with the increase of pulse duration and PRF, but mechanical erosion reached its maximum volume with the pulse duration of 20 ms and PRF of 1 Hz. Altogether, bubble cavitation and thermal field vary with the progress of HIFU treatment with different sonication parameters, which provide insights into the interaction of ultrasound burst with the induced bubbles for both soft tissue fractionation and enhancement in thermal accumulation. Appropriate synergy and monitoring of mechanical and thermal effects would broaden the HIFU application and enhance its efficiency as well as safety.

Test Guide for ADS-33E-PRF

DTIC Science & Technology

2008-07-01

8501A (Reference 2), and from the V/STOL specification MIL-F-83300 (Reference 3). ADS-33E-PRF contains intermeshed requirements on not only shoi -t- and...While final verification will in most cases require flight testing, initial checks can be performed through analysis and on ground-based simulators...they are difficult to test, or for some reason are deficient in one or more areas. In such cases one or more alternate criteria are presented where

AN/TPN-14 Precision Approach Radar (PAR) Analysis

DTIC Science & Technology

1964-05-01

to install high -pass filters on the transmitter power lines, or (2) change the PRF to, for example, 1400 cps to give maximum separation of the PRF...consist of a high voltage power supply, pulse forming and transmitting circuitry, and necessary control circuitry. It shall have a pulse type...1200 cycles per second and a pulse width of 0. 2 or 0. 8 microseconds selectable. 3. 5. 5. 1 High voltage power supply. - The high voltage power

The influence of platelet-rich fibrin on angiogenesis in guided bone regeneration using xenogenic bone substitutes: a study of rabbit cranial defects.

PubMed

Yoon, Jong-Suk; Lee, Sang-Hwa; Yoon, Hyun-Joong

2014-10-01

The purpose of this study was to investigate the influence of platelet-rich fibrin (PRF) on angiogenesis and osteogenesis in guided bone regeneration (GBR) using xenogenic bone in rabbit cranial defects. In each rabbit, 2 circular bone defects, one on either side of the midline, were prepared using a reamer drill. Each of the experimental sites received bovine bone with PRF, and each of the control sites received bovine bone alone. The animals were sacrificed at 1 week (n = 4), 2 weeks (n = 3) and 4 weeks (n = 3). Biopsy samples were examined histomorphometrically by light microscopy, and expression of vascular endothelial growth factor (VEGF) was determined by immunohistochemical staining. At all experimental time points, immunostaining intensity for VEGF was consistently higher in the experimental group than in the control group. However, the differences between the control group and the experimental group were not statistically significant in the histomorphometrical and immunohistochemical examinations. The results of this study suggest that PRF may increase the number of marrow cells. However, PRF along with xenogenic bone substitutes does not show a significant effect on bony regeneration. Further large-scale studies are needed to confirm our results. Copyright © 2014 European Association for Cranio-Maxillo-Facial Surgery. Published by Elsevier Ltd. All rights reserved.

The use of platelet-rich fibrin combined with periodontal ligament and jaw bone mesenchymal stem cell sheets for periodontal tissue engineering

PubMed Central

Wang, Zhong-Shan; Feng, Zhi-Hong; Wu, Guo-Feng; Bai, Shi-Zhu; Dong, Yan; Chen, Fa-Ming; Zhao, Yi-Min

2016-01-01

Periodontal regeneration involves the restoration of at least three unique tissues: cementum, periodontal ligament tissue (PDL) and alveolar bone tissue. Here, we first isolated human PDL stem cells (PDLSCs) and jaw bone mesenchymal stem cells (JBMSCs). These cells were then induced to form cell sheets using an ascorbic acid-rich approach, and the cell sheet properties, including morphology, thickness and gene expression profile, were compared. Platelet-rich fibrin (PRF) derived from human venous blood was then fabricated into bioabsorbable fibrin scaffolds containing various growth factors. Finally, the in vivo potential of a cell-material construct based on PDLSC sheets, PRF scaffolds and JBMSC sheets to form periodontal tissue was assessed in a nude mouse model. In this model, PDLSC sheet/PRF/JBMSC sheet composites were placed in a simulated periodontal space comprising human treated dentin matrix (TDM) and hydroxyapatite (HA)/tricalcium phosphate (TCP) frameworks. Eight weeks after implantation, the PDLSC sheets tended to develop into PDL-like tissues, while the JBMSC sheets tended to produce predominantly bone-like tissues. In addition, the PDLSC sheet/PRF/JBMSC sheet composites generated periodontal tissue-like structures containing PDL- and bone-like tissues. Further improvements in this cell transplantation design may have the potential to provide an effective approach for future periodontal tissue regeneration. PMID:27324079

Failed CTL/NK cell killing and cytokine hypersecretion are directly linked through prolonged synapse time

PubMed Central

Rudd-Schmidt, Jesse A.; Lopez, Jamie A.; Ramsbottom, Kelly M.; Mannering, Stuart I.; Andrews, Daniel M.; Voskoboinik, Ilia

2015-01-01

Failure of cytotoxic T lymphocytes (CTLs) or natural killer (NK) cells to kill target cells by perforin (Prf)/granzyme (Gzm)-induced apoptosis causes severe immune dysregulation. In familial hemophagocytic lymphohistiocytosis, Prf-deficient infants suffer a fatal “cytokine storm” resulting from macrophage overactivation, but the link to failed target cell death is not understood. We show that prolonged target cell survival greatly amplifies the quanta of inflammatory cytokines secreted by CTLs/NK cells and that interferon-γ (IFN-γ) directly invokes the activation and secondary overproduction of proinflammatory IL-6 from naive macrophages. Furthermore, using live cell microscopy to visualize hundreds of synapses formed between wild-type, Prf-null, or GzmA/B-null CTLs/NK cells and their targets in real time, we show that hypersecretion of IL-2, TNF, IFN-γ, and various chemokines is linked to failed disengagement of Prf- or Gzm-deficient lymphocytes from their targets, with mean synapse time increased fivefold, from ∼8 to >40 min. Surprisingly, the signal for detachment arose from the dying target cell and was caspase dependent, as delaying target cell death with various forms of caspase blockade also prevented their disengagement from fully competent CTLs/NK cells and caused cytokine hypersecretion. Our findings provide the cellular mechanism through which failed killing by lymphocytes causes systemic inflammation involving recruitment and activation of myeloid cells. PMID:25732304

Evaluation of periosteum eversion and coronally advanced flap techniques in the treatment of isolated Miller's Class I/II gingival recession: A comparative clinical study

PubMed Central

Debnath, Koel; Chatterjee, Anirban

2018-01-01

Aim: The present investigation aimed to evaluate root coverage (RC) with periosteum eversion technique (PET) using periosteum as a graft and coronally advanced flap (CAF) with platelet-rich fibrin (PRF) membrane as a graft in the treatment of isolated Miller's class I and II gingival recession defects. Materials and Methods: Thirty sites in 15 participants with Miller's Class I or II gingival recession were randomly treated either with PET using periosteum as graft and CAF + PRF as graft. In a split mouth design, the parameters such as recession depth, recession width at cementoenamel junction, probing depth, periodontal attachment level (PAL), and keratinized gingival width were assessed at baseline, 3 months, and 6 months postoperative follow-up with William's graduated probe and Vernier caliper. Results: Both the treatment modalities yielded statistically nonsignificant desirable treatment outcomes at both postoperative levels in terms of all the parameters The mean RC with probe method and Vernier method in CAF + PRF was 75.01% and 86.86%, respectively, and PET showed a mean RC of 61.112% and 83.971%, respectively, at 6-month interval period which showed a nonstatistically significant difference. Conclusion: Both the treatment modalities, i.e., CAF + PRF and PET are essentially and equally effective in the treatment of Miller's Class I or II gingival recession defects. PMID:29769769

Carbachol injection into the pontine reticular formation depresses laryngeal muscle activities and airway reflexes in decerebrate cats.

PubMed

Adachi, Masaaki; Nonaka, Satoshi; Katada, Akihiro; Arakawa, Takuya; Ota, Ryo; Harada, Hirofumi; Takakusaki, Kaoru; Harabuchi, Yasuaki

2010-05-01

To understand the role of cholinoceptive, medial pontine reticular formation (mPRF) neurons in the control of upper airway, pharyngolaryngeal reflexes, we measured activities of intrinsic laryngeal muscles (posterior cricoarytenoid, PCA; thyroarytenoid, TA), diaphragm (DIA), genioglossus (GG) and a neck muscle (trapezius) in unanesthetized, decerebrated, spontaneously breathing cats with and without mPRF carbachol injections. The ethimoidal nerve was electrically stimulated to evoke sneezing, and the superior laryngeal nerve to evoke the laryngeal reflex, swallowing, and coughing. Carbachol reduced the amplitudes of the spontaneous electromyographic activities in the neck, TA, PCA, GG, and DIA to 7%, 30%, 54%, 45% and 71% of control, respectively, reduced the respiratory rate to 53% without changes in expiratory CO(2) concentration; the magnitude of the laryngeal reflex in the TA muscle to 56%; increased its latency by 13%; and reduced the probability of stimulus-induced sneezing, swallowing, and coughing to less than 40%. These changes lasted more than 1h. These data demonstrate that important upper airway reflexes are suppressed by increasing cholinergic neurotransmission in the mPRF. Because acetylcholine release in the mPRF changes in accordance with sleep-wake cycles, the present findings are relevant to the control of upper airway reflexes during various vigilance states. 2010 Elsevier Ireland Ltd and the Japan Neuroscience Society. All rights reserved.

Banning PRF programmer's manual. [considering MOS integrated circuits

NASA Technical Reports Server (NTRS)

Kuelthau, R. L.

1970-01-01

This manual describes a modification of the Banning placement routing folding program. The modifications to this program have been made to implement it on a Sigma 5 computer. Flow charts of various levels, beginning with high level functional diagrams and working down to the level of detail deemed necessary to understand the operations of the various sections of the program are included. Along with the flow charts of each subroutine is a narrative description of its functional operation and definitions of its arrays and key variables, and a section to assist the programmer in dimensioning the program's arrays.

Effects of Platelet-Poor Plasma, Platelet-Rich Plasma, and Platelet-Rich Fibrin on Healing of Extraction Sockets with Buccal Dehiscence in Dogs

PubMed Central

Hatakeyama, Ichiro; Takahashi, Yukinobu; Omura, Ken

2014-01-01

Alveolar bone resorption generally occurs during healing after tooth extraction. This study aimed to evaluate the effects of platelet-poor plasma (PPP), platelet-rich plasma (PRP), and platelet-rich fibrin (PRF) on healing in a ridge-augmentation model of the canine socket with dehiscence of the buccal wall. The third mandibular premolars of 12 beagle dogs were extracted and a 3 mm buccal dehiscence from the alveolar crest to the buccal wall of the extraction socket was created. These sockets were then divided into four groups on the basis of the material used to fill the sockets: PPP, PRP, PRF, and control (no graft material) groups. Results were evaluated at 4 and 8 weeks after surgery. The ultrastructural morphology and constructs of each blood product were studied by a scanning electron microscope (SEM) or calculating concentrations of platelets, fibrinogen, platelet-derived growth factor, and transforming growth factor-β. A total of five microcomputed tomography images of specimens were selected for measurement, and the area occupied by the newly formed bone as well as the horizontal bone width were measured. Moreover, decalcified tissue specimens from each defect were analyzed histologically. The median area of new bone at 4 and 8 weeks and median horizontal bone width at 8 weeks were the highest in the PPP group. However, bone maturation in the PRF and the PRP groups was more progressed than that in the PPP and control groups. By SEM findings, the PRF group showed a more highly condensed fibrin fiber network that was regularly arranged when compared with the PPP and PRP groups. The growth factors released from platelets in PRP indicated higher concentrations than that in PRF. Under more severe conditions for bone formation, as in this experiment, the growth factors released from platelets had a negative effect on bone formation. This study showed that PPP is an effective material for the preservation of sockets with buccal dehiscence. PMID:24098948

Virulence Gene Sequencing Highlights Similarities and Differences in Sequences in Listeria monocytogenes Serotype 1/2a and 4b Strains of Clinical and Food Origin From 3 Different Geographic Locations.

PubMed

Poimenidou, Sofia V; Dalmasso, Marion; Papadimitriou, Konstantinos; Fox, Edward M; Skandamis, Panagiotis N; Jordan, Kieran

2018-01-01

The prfA -virulence gene cluster ( p VGC) is the main pathogenicity island in Listeria monocytogenes , comprising the prfA, plcA, hly, mpl, actA , and plcB genes. In this study, the p VGC of 36 L. monocytogenes isolates with respect to different serotypes (1/2a or 4b), geographical origin (Australia, Greece or Ireland) and isolation source (food-associated or clinical) was characterized. The most conserved genes were prfA and hly , with the lowest nucleotide diversity (π) among all genes ( P < 0.05), and the lowest number of alleles, substitutions and non-synonymous substitutions for prfA . Conversely, the most diverse gene was actA , which presented the highest number of alleles ( n = 20) and showed the highest nucleotide diversity. Grouping by serotype had a significantly lower π value ( P < 0.0001) compared to isolation source or geographical origin, suggesting a distinct and well-defined unit compared to other groupings. Among all tested genes, only hly and mpl were those with lower nucleotide diversity in 1/2a serotype than 4b serotype, reflecting a high within-1/2a serotype divergence compared to 4b serotype. Geographical divergence was noted with respect to the hly gene, where serotype 4b Irish strains were distinct from Greek and Australian strains. Australian strains showed less diversity in plcB and mpl relative to Irish or Greek strains. Notable differences regarding sequence mutations were identified between food-associated and clinical isolates in prfA, actA , and plcB sequences. Overall, these results indicate that virulence genes follow different evolutionary pathways, which are affected by a strain's origin and serotype and may influence virulence and/or epidemiological dominance of certain subgroups.

Comparative evaluation of the isolation and quantification of stem cells derived from dental pulp and periodontal ligament of a permanent tooth and to assess their viability and proliferation on a platelet-rich fibrin scaffold

PubMed Central

Khurana, Rohit; Kudva, Praveen Bhasker; Husain, Syed Yawer

2017-01-01

Background: The present study aims to comparatively evaluate the isolation and quantification of stem cells derived from dental pulp and periodontal ligament of a permanent tooth and to assess their viability and proliferation on a platelet-rich fibrin (PRF) scaffold. Materials and Methods: A total of 15 systemically healthy individuals between the age group of 15–25 years requiring third molar or orthodontic premolar extractions. Teeth were extracted atraumatically and transported to the laboratory. Stem cells were isolated from dental pulp and periodontal ligament. After attaining more than 90% confluency by the 7th day, these cells were tested for their viability and characterization. Stem cells were also incubated with PRF and viability was assessed on the 7th day. Results: The mean number of cell for dental pulp stem cells (DPSCs) and periodontal ligament stem cell (PDLSC) was statistically insignificant (P > 0.05). The mean live cell viability was compared between DPSC (98.07%) and PDLSC (98%). Both DPSC and PDLSC showed a high percentage of expression of CD73 markers, 30.40% and 29.80%, respectively. However, DPSCs and PDLSCs lacked expression of CD34 expressing only 3.47% and 3.53%, respectively. PRF membrane as a scaffold exhibited no cytotoxic effects on DPCS's or PDLSC's. The cell viability of cells cultured with PRF was statistically insignificant (P > 0.05) when compared to the cells cultured with culture media. Conclusion: The study thus indicates that dental pulp and periodontal ligament are both rich sources of mesenchymal stem cells and can be successfully used for obtaining stem cells. PRF exhibits no cytotoxic effects on the cells and can be used in conjunction with dental stem cells. PMID:29386795

The Treatment of Joint Pain with Intra-articular Pulsed Radiofrequency.

PubMed

Schianchi, Pietro M; Sluijter, Menno E; Balogh, Susan E

2013-09-01

The intra-articular (IA) application of pulsed radiofrequency (PRF) for pain in small and large joints represents a recent development that has proven to be effective in many cases. We performed a retrospective study of 89 such procedures in 57 consecutive patients with chronic articular pain. The aim of this retrospective study is to evaluate the effectiveness of intraarticular PRF in a group of 57 consecutive patients with chronic joint pain. Patients with intractable joint pain for more than 6 months were treated with IA PRF 40-45V for 10-15 min in small joints and 60V for 15 min in large joints using fluoroscopic confirmation of correct needle position. A total of 28 shoulders, 40 knees, 10 trapezio-metacarpal, and 11 first metatarso-phalangeal joints were treated. Results were evaluated at 1, 2, and 5 months. The procedure was repeated after 1 month in 10 patients with initial suboptimal results. Success was defined as a reduction of pain score by at least 50%. All groups showed significant reductions in pain scores at all three follow-up visits. Success rates were higher in small joints (90% and 82%, respectively) than large ones (64% and 60%, respectively). Interestingly, IA PRF was successful in 6 out of 10 patients who had undergone previous surgery, including 3 with prosthetic joint replacement and in 6 of the 10 repeated procedures. There were no significant adverse effects or complications. IA PRF induced significant pain relief of long duration in a majority of our patients with joint pain. The exact mechanism is unclear, but may be related to the exposure of immune cells to low-strength RF fields, inducing an anti-inflammatory effect. The success rate appears to be highest in small joints. We recommend additional research including control groups to further investigate and clarify this method; our data suggest that it may represent a useful modality in the treatment of arthrogenic pain.

Effects of platelet-poor plasma, platelet-rich plasma, and platelet-rich fibrin on healing of extraction sockets with buccal dehiscence in dogs.

PubMed

Hatakeyama, Ichiro; Marukawa, Eriko; Takahashi, Yukinobu; Omura, Ken

2014-02-01

Alveolar bone resorption generally occurs during healing after tooth extraction. This study aimed to evaluate the effects of platelet-poor plasma (PPP), platelet-rich plasma (PRP), and platelet-rich fibrin (PRF) on healing in a ridge-augmentation model of the canine socket with dehiscence of the buccal wall. The third mandibular premolars of 12 beagle dogs were extracted and a 3 mm buccal dehiscence from the alveolar crest to the buccal wall of the extraction socket was created. These sockets were then divided into four groups on the basis of the material used to fill the sockets: PPP, PRP, PRF, and control (no graft material) groups. Results were evaluated at 4 and 8 weeks after surgery. The ultrastructural morphology and constructs of each blood product were studied by a scanning electron microscope (SEM) or calculating concentrations of platelets, fibrinogen, platelet-derived growth factor, and transforming growth factor-β. A total of five microcomputed tomography images of specimens were selected for measurement, and the area occupied by the newly formed bone as well as the horizontal bone width were measured. Moreover, decalcified tissue specimens from each defect were analyzed histologically. The median area of new bone at 4 and 8 weeks and median horizontal bone width at 8 weeks were the highest in the PPP group. However, bone maturation in the PRF and the PRP groups was more progressed than that in the PPP and control groups. By SEM findings, the PRF group showed a more highly condensed fibrin fiber network that was regularly arranged when compared with the PPP and PRP groups. The growth factors released from platelets in PRP indicated higher concentrations than that in PRF. Under more severe conditions for bone formation, as in this experiment, the growth factors released from platelets had a negative effect on bone formation. This study showed that PPP is an effective material for the preservation of sockets with buccal dehiscence.

Antitumor effects of vitamins K1, K2 and K3 on hepatocellular carcinoma in vitro and in vivo.

PubMed

Hitomi, Misuzu; Yokoyama, Fumi; Kita, Yuko; Nonomura, Takako; Masaki, Tsutomu; Yoshiji, Hitoshi; Inoue, Hideyuki; Kinekawa, Fumihiko; Kurokohchi, Kazutaka; Uchida, Naohito; Watanabe, Seishiro; Kuriyama, Shigeki

2005-03-01

A number of studies have shown that various K vitamins, specifically vitamins K2 and K3, possess antitumor activity on various types of rodent- and human-derived neoplastic cell lines. In the present study, we examined the antitumor effects of vitamins K1, K2 and K3 on PLC/PRF/5 human hepatocellular carcinoma (HCC) cells in vitro and in vivo. Furthermore, we examined the mechanisms of antitumor actions of these vitamins in vitro and in vivo. Although vitamin K1 did not inhibit proliferation of PLC/PRF/5 cells at a 90-microM concentration (the highest tested), vitamins K2 and K3 suppressed proliferation of the cells at concentrations of 90 and 9 microM, respectively. By flow cytometric analysis, it was shown that not only vitamin K1, but also vitamin K2 did not induce apoptosis or cell cycle arrest on PLC/PRF/5 cells. In contrast, vitamin K3 induced G1 arrest, but not apoptosis on PLC/PRF/5 cells. Subsequent in vivo study using subcutaneous HCC-bearing athymic nude mice demonstrated that both vitamins K2 and K3 markedly suppressed the growth of HCC tumors to similar extent. Protein expression of cyclin D1 and cyclin-dependent kinase 4 (Cdk4), but not p16INK4a Cdk inhibitor in the tumor was significantly reduced by vitamin K2 or K3 treatment, indicating that vitamins K2 and K3 may induce G1 arrest of cell cycle on PLC/PRF/5 cells in vivo. Taken collectively, vitamins K2 and K3 were able to induce potent antitumor effects on HCC in vitro and in vivo, at least in part, by inducing G1 arrest of the cell cycle. The results indicate that vitamins K2 and K3 may be useful agents for the treatment of patients with HCC.

Incorporating AFEWC IMOM as an Instructional Asset for NPS Radar and Electronic Warfare Curricula

DTIC Science & Technology

1992-09-01

Backlobe EL. dB down - 20 dB Backlobe AZ. dB down = 20 dB Ru - 400 km 215.983 nmi Scope Range = 200 km 107.991 nmi PRF = 375 Hz Pay = 600 W RCS = 10 sq m...10 dB Backlobe EL. dB down = 20 dB Backlobe AZ. dB down = 20 dB Ru = 400 km 215.983 nmi Scope Range = 400 km 215.983 nmi PRF = 375 Hz Pay = 93.75 W

Versatile Chromium-Doped Zinc Selenide Infrared Laser Sources

DTIC Science & Technology

2010-05-01

ability of the fixed- angle curved mirrors in the Z- cavity to compensate for the increasing astigmatism from the Brewster - angle thermal lens in the...duty cycle at varying PRFs. 20 Table 4: Thermal Lensing Power at 1 kHz PRF, 1 W peak power, Q-switched Laser PRF (kHz) Thermal lens power (m-1...with it some negative astigmatism effects which are compounded by thermal lensing in the crystal which is now at an angle . To counteract this

Platelet-rich fibrin in the treatment of periodontal bone defects.

PubMed

Ranganathan, Aravindhan T; Chandran, Chitraa R

2014-05-01

Periodontitis is characterized by the formation of true pockets, bone loss and attachment loss. Various techniques have been attempted in the past to truly regenerate the lost periodontal structures, albeit with variable outcome. In this evolution, the technique being tried out widely is the use of platelet rich concentrates, namely platelet-rich fibrin (PRF). In this report, we present a case of surgical treatment of osseous bone defects namely two walled crater and dehiscence treated in posterior teeth with autologously prepared platelet rich fibrin mixed with hydroxy apatite bone graft and PRF in the form of a membrane. Our results showed clinical improvements in all the clinical parameters postoperatively namely the pocket depth reduction and gain in attachment level and hence, PRF can be used alone or in combination with the bone graft to yield successful clinical results in treating periodontal osseous defects. Platelet-rich fibrin is an effective alternative to platelet-rich plasma (PRP) in reconstructing bone defects.

LD-pumped actively Q-switched c-cut Nd:GdVO4 self-Raman laser operating at 1166 and 1176 nm

NASA Astrophysics Data System (ADS)

Sun, Xinzhi; Zhang, Xihe; Li, Shutao; Dong, Yuan

2017-12-01

A laser diode pumped actively Q-switched c-cut Nd:GdVO4 self-Raman laser is experimentally investigated. Simultaneous pulse outputs at 1166 nm and 1176 nm corresponding to the Raman shifts of 807 and 882 cm-1 are acquired. At the pulse repetition frequency (PRF) of 20 kHz, the maximum output power is 103 mW at 1166 nm with the incident pump power of 2.31 W, while 1176 nm output power reaches 530 mW with the incident pump power of 4.11 W. The maximum output power of Raman laser is 570 mW with the incident pump power of 4.11 W and the PRF of 30 kHz. With the incident pump power of 3.67 W and the PRF of 30 kHz, the highest diode-to-Stokes optical conversion efficiency of 14.9% is obtained with the corresponding average output power of 547 mW.

A Systematic Investigation of Parameters Influencing Droplet Rain in the Listeria monocytogenes prfA Assay - Reduction of Ambiguous Results in ddPCR

PubMed Central

Witte, Anna Kristina; Mester, Patrick; Fister, Susanne; Witte, Matthias; Schoder, Dagmar; Rossmanith, Peter

2016-01-01

The droplet digital polymerase chain reaction (ddPCR) determines DNA amounts based upon the pattern of positive and negative droplets, according to Poisson distribution, without the use of external standards. However, division into positive and negative droplets is often not clear because a part of the droplets has intermediate fluorescence values, appearing as “rain” in the plot. Despite the droplet rain, absolute quantification with ddPCR is possible, as shown previously for the prfA assay in quantifying Listeria monocytogenes. Nevertheless, reducing the rain, and thus ambiguous results, promotes the accuracy and credibility of ddPCR. In this study, we extensively investigated chemical and physical parameters for optimizing the prfA assay for ddPCR. While differences in the concentration of all chemicals and the dye, quencher and supplier of the probe did not alter the droplet pattern, changes in the PCR cycling program, such as prolonged times and increased cycle numbers, improved the assay. PMID:27992475

A Systematic Investigation of Parameters Influencing Droplet Rain in the Listeria monocytogenes prfA Assay - Reduction of Ambiguous Results in ddPCR.

PubMed

Witte, Anna Kristina; Mester, Patrick; Fister, Susanne; Witte, Matthias; Schoder, Dagmar; Rossmanith, Peter

2016-01-01

The droplet digital polymerase chain reaction (ddPCR) determines DNA amounts based upon the pattern of positive and negative droplets, according to Poisson distribution, without the use of external standards. However, division into positive and negative droplets is often not clear because a part of the droplets has intermediate fluorescence values, appearing as "rain" in the plot. Despite the droplet rain, absolute quantification with ddPCR is possible, as shown previously for the prfA assay in quantifying Listeria monocytogenes. Nevertheless, reducing the rain, and thus ambiguous results, promotes the accuracy and credibility of ddPCR. In this study, we extensively investigated chemical and physical parameters for optimizing the prfA assay for ddPCR. While differences in the concentration of all chemicals and the dye, quencher and supplier of the probe did not alter the droplet pattern, changes in the PCR cycling program, such as prolonged times and increased cycle numbers, improved the assay.

Influence of shock wave pressure amplitude and pulse repetition frequency on the lifespan, size and number of transient cavities in the field of an electromagnetic lithotripter.

PubMed

Huber, P; Jöchle, K; Debus, J

1998-10-01

Monitoring the generation of cavitation is of great interest for diagnostic and therapeutic use of ultrasound in medicine, since cavitation is considered to play a major role in nonthermal ultrasound interactions with tissue. Important parameters are the number of cavitation events and the energy released during the bubble collapse. This energy is correlated to the maximum bubble radius which is related to the cavitation lifespan. The aim of this study was therefore to investigate the influence of the acoustic pressure amplitude and the pulse repetition frequency (PRF) in the field of a lithotripter (Lithostar, Siemens) on the number, size and lifespan of transient cavitation bubbles in water. We used scattered laser light recorded by a photodiode and stroboscopic photographs to monitor the cavitation activity. We found that PRF (range 0.5-5 Hz) had no influence on the cavitation bubble lifespan and size, whereas lifespan and size increased with the acoustic pressure amplitude. In contrast, the number of cavitation events strongly increased with PRF, whereas the pressure amplitude had no significant influence on the number of cavitation events. Thus, by varying the pressure amplitude and PRF, it might be possible to deliver a defined relative number of cavitations at a defined relative energy level in a defined volume. This seems to be relevant to further studies that address the biological effects of transient cavitation occurring in the fields of lithotripters.

Adjunctive Effect of Autologus Platelet-Rich Fibrin to Barrier Membrane in the Treatment of Periodontal Intrabony Defects.

PubMed

Panda, Saurav; Sankari, Malaiappan; Satpathy, Anurag; Jayakumar, Doraiswamy; Mozzati, Marco; Mortellaro, Carmen; Gallesio, Giorgia; Taschieri, Silvio; Del Fabbro, Massimo

2016-05-01

Autologous platelet-rich fibrin (PRF) and barrier membranes in the treatment of intrabony defects in chronic periodontitis patients have shown significant clinical benefits. This study evaluates the additive effect of autologous PRF in combination with a barrier membrane versus the use of barrier membrane alone for the treatment of intrabony defects in chronic periodontitis patients. A randomized split-mouth design was used. Sixteen patients with 32 paired intrabony defects were included. In each patient 1 defect was treated using a resorbable collagen membrane along with PRF (test group) and the other defect by guided tissue regeneration alone (control group). The following clinical parameters were measured at baseline and after 9 months: plaque index, modified sulcus bleeding index, probing pocket depth, clinical attachment level, and gingival marginal level. The radiographic defect depth was also assessed at baseline and after 9 months. Test group showed a statistically significant improvement for probing depth (P = 0.002), clinical attachment level (P = 0.001), and radiographic defect depth (P < 0.001) after 9 months as compared with the control sites. Radiographic defect depth reduction was 58.19 ± 13.24% in the test group as compared with 24.86 ± 9.94% reduction in the control group. The adjunctive use of PRF in combination with barrier membrane is more effective in the treatment of intrabony defects in chronic periodontitis as compared with barrier membrane alone.

Effects of platelet-rich fibrin on healing of intra-bony defects treated with anorganic bovine bone mineral.

PubMed

Sezgin, Yasemin; Uraz, Ahu; Taner, I Levent; Çulhaoğlu, Rana

2017-01-26

Anorganic bovine bone mineral (ABBM) is extensively used in the treatment of intra-bony defects. Platelet-rich fibrin (PRF) is a new-generation platelet concentrate with a simplified technique. Although certain studies have reported the use of PRF in the treatment of intra-bony defects, to date, none of them have evaluated its additive effects with ABBM. Therefore, a randomised, split-mouth clinical trial was conducted to compare healing of intra-bony defects treated with an ABBM-PRF combination with healing of those treated with ABBM alone. By using a split-mouth design, 15 paired intra-bony defects were randomly treated with either ABBM alone (control group) or ABBM-PRF combination (test group). Following clinical parameters and radiographical measurements were recorded at baseline and 6 months after treatment: plaque index (PI), gingival index (GI), probing depth (PD), gingival recession (GR), clinical attachment level (CAL), vertical bone loss, depth of defect and defect angle. Preoperative clinical and radiographical measurements were similar for the test and control groups. Statistically significant reductions in GI, PD, CAL, vertical bone loss, depth of intra-bony defect and widening of defect angle were detected after treatment in both groups. With respect to inter-group analysis, gain in CAL was significantly greater in the test group than in the control group, whereas no inter-group differences were observed in any other parameter. The results of this study indicate that both therapies are effective in the treatment of intra-bony defects.

Effect of carbonated hydroxyapatite incorporated advanced platelet rich fibrin intrasulcular injection on the alkaline phosphatase level during orthodontic relapse

NASA Astrophysics Data System (ADS)

Alhasyimi, Ananto Ali; Pudyani, Pinandi Sri; Asmara, Widya; Ana, Ika Dewi

2018-02-01

Nowadays, relapse in orthodontic treatment is considered very important because of high incidence of relapse after the treatment. Alkaline phosphatase (ALP) as a biomarker of bone formation will decrease in compression sites during relapse after orthodontic tooth movement. In this situation, manipulating alveolar bone remodeling to increase ALP level is considered one of the new strategies to prevent relapse properly. In the field of tissue engineering, in this study, carbonated hydroxyapatite (CHA) is expected to have the ability to incorporate advanced platelet rich fibrin (aPRF). Next, CHA will retain the aPRF containing various growth factors (GF) until it reaches into a specific targeted area, gradually degraded, and deliver the GF in a controlled manner to prevent relapse. Here, gingival crevicular fluid (GCF) of 45 samples (n=45) were collected and levels of ALP were analyzed using UV-Vis 6300 Spectrophotometer at 405 nm wavelength. We found that there is a significant difference of ALP levels (p<0.05) in GCF between treatments and control groups. ALP level was elevated significantly in CHA and CHA-aPRF groups at days 7 and 14 after debonding compared with the control groups. The peak level of ALP was observed at days 14 after debonding in groups C (0.789 ± 0.039 U/mg). Therefore, it can be concluded that the application of hydrogel CHA with controlled release manner incorporated aPRF enhances bone regeneration by increasing ALP level.

Identification of Two Novel Amalgaviruses in the Common Eelgrass (Zostera marina) and in Silico Analysis of the Amalgavirus +1 Programmed Ribosomal Frameshifting Sites.

PubMed

Park, Dongbin; Goh, Chul Jun; Kim, Hyein; Hahn, Yoonsoo

2018-04-01

The genome sequences of two novel monopartite RNA viruses were identified in a common eelgrass ( Zostera marina ) transcriptome dataset. Sequence comparison and phylogenetic analyses revealed that these two novel viruses belong to the genus Amalgavirus in the family Amalgaviridae . They were named Zostera marina amalgavirus 1 (ZmAV1) and Zostera marina amalgavirus 2 (ZmAV2). Genomes of both ZmAV1 and ZmAV2 contain two overlapping open reading frames (ORFs). ORF1 encodes a putative replication factory matrix-like protein, while ORF2 encodes a RNA-dependent RNA polymerase (RdRp) domain. The fusion protein (ORF1+2) of ORF1 and ORF2, which mediates RNA replication, was produced using the +1 programmed ribosomal frameshifting (PRF) mechanism. The +1 PRF motif sequence, UUU_CGN, which is highly conserved among known amalgaviruses, was also found in ZmAV1 and ZmAV2. Multiple sequence alignment of the ORF1+2 fusion proteins from 24 amalgaviruses revealed that +1 PRF occurred only at three different positions within the 13-amino acid-long segment, which was surrounded by highly conserved regions on both sides. This suggested that the +1 PRF may be constrained by the structure of fusion proteins. Genome sequences of ZmAV1 and ZmAV2, which are the first viruses to be identified in common eelgrass, will serve as useful resources for studying evolution and diversity of amalgaviruses.

Identification of Two Novel Amalgaviruses in the Common Eelgrass (Zostera marina) and in Silico Analysis of the Amalgavirus +1 Programmed Ribosomal Frameshifting Sites

PubMed Central

Park, Dongbin; Goh, Chul Jun; Kim, Hyein; Hahn, Yoonsoo

2018-01-01

The genome sequences of two novel monopartite RNA viruses were identified in a common eelgrass (Zostera marina) transcriptome dataset. Sequence comparison and phylogenetic analyses revealed that these two novel viruses belong to the genus Amalgavirus in the family Amalgaviridae. They were named Zostera marina amalgavirus 1 (ZmAV1) and Zostera marina amalgavirus 2 (ZmAV2). Genomes of both ZmAV1 and ZmAV2 contain two overlapping open reading frames (ORFs). ORF1 encodes a putative replication factory matrix-like protein, while ORF2 encodes a RNA-dependent RNA polymerase (RdRp) domain. The fusion protein (ORF1+2) of ORF1 and ORF2, which mediates RNA replication, was produced using the +1 programmed ribosomal frameshifting (PRF) mechanism. The +1 PRF motif sequence, UUU_CGN, which is highly conserved among known amalgaviruses, was also found in ZmAV1 and ZmAV2. Multiple sequence alignment of the ORF1+2 fusion proteins from 24 amalgaviruses revealed that +1 PRF occurred only at three different positions within the 13-amino acid-long segment, which was surrounded by highly conserved regions on both sides. This suggested that the +1 PRF may be constrained by the structure of fusion proteins. Genome sequences of ZmAV1 and ZmAV2, which are the first viruses to be identified in common eelgrass, will serve as useful resources for studying evolution and diversity of amalgaviruses. PMID:29628822

Comparative evaluation of platelet-rich fibrin and mineral trioxide aggregate as pulpotomy agents in permanent teeth with incomplete root development: a randomized controlled trial.

PubMed

Keswani, Deepa; Pandey, Ramesh K; Ansari, Afroz; Gupta, Shalini

2014-05-01

The purpose of this study was to evaluate and compare, clinically and radiographically, the effects of platelet-rich fibrin (PRF) and mineral trioxide aggregate (MTA) as pulpotomy agents in permanent teeth with incomplete root development. A total number of 70 children requiring pulpotomy in 70 permanent molars with incomplete root development were screened. Sixty-two patients met the inclusion criteria and were enrolled in the study. The patients were randomly allocated equally in 2 treatment groups. MTA pulpotomy was performed in group A (the control group), and PRF pulpotomy was performed in group B (the experimental group). The treated teeth were restored with amalgam followed by stainless steel crowns. Clinical and radiographic evaluations were performed after 6, 12, and 24 months. Thus, the data obtained were blindly analyzed using the chi-square test. There was no significant difference between the 2 groups in terms of clinical and radiologic success. Radiographically, all available cases (53 teeth) showed evidence of root growth and canal narrowing. Complete apical closure was observed in 88.8% in the PRF group (experimental group) and 80.07% of roots in the MTA group (control group), respectively, at 24 months. PRF could be used as a suitable biological and economic alternative to MTA in pulpotomy procedures of permanent teeth with incomplete root development. Copyright © 2014 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

Comparative analysis of TGF-β/Smad signaling dependent cytostasis in human hepatocellular carcinoma cell lines.

PubMed

Dzieran, Johanna; Fabian, Jasmin; Feng, Teng; Coulouarn, Cédric; Ilkavets, Iryna; Kyselova, Anastasia; Breuhahn, Kai; Dooley, Steven; Meindl-Beinker, Nadja M

2013-01-01

Hepatocellular carcinoma (HCC) is a major public health problem due to increased incidence, late diagnosis and limited treatment options. TGF-β is known to provide cytostatic signals during early stages of liver damage and regeneration, but exerts tumor promoting effects in onset and progression of liver cancer. To understand the mechanistic background of such a switch, we systematically correlated loss of cytostatic TGF-β effects with strength and dynamics of its downstream signaling in 10 HCC cell lines. We demonstrate that TGF-β inhibits proliferation and induces apoptosis in cell lines with low endogenous levels of TGF-β and Smad7 and strong transcriptional Smad3 activity (PLC/PRF/5, HepG2, Hep3B, HuH7), previously characterized to express early TGF-β signatures correlated with better outcome in HCC patients. TGF-β dependent cytostasis is blunted in another group of cell lines (HLE, HLF, FLC-4) expressing high amounts of TGF-β and Smad7 and showing significantly reduced Smad3 signaling. Of those, HLE and HLF exhibit late TGF-β signatures, which is associated with bad prognosis in HCC patients. RNAi with Smad3 blunted cytostatic effects in PLC/PRF/5, Hep3B and HuH7. HCC-M and HCC-T represent a third group of cell lines lacking cytostatic TGF-β signaling despite strong and prolonged Smad3 phosphorylation and low Smad7 and TGF-β expression. Inhibitory linker phosphorylation, as in HCC-T, may disrupt C-terminally phosphorylated Smad3 function. In summary, we assort 10 HCC cell lines in at least two clusters with respect to TGF-β sensitivity. Cell lines responsive to the TGF-β cytostatic program, which recapitulate early stage of liver carcinogenesis exhibit transcriptional Smad3 activity. Those with disturbed TGF-β/Smad3 signaling are insensitive to TGF-β dependent cytostasis and might represent late stage of the disease. Regulation of this switch remains complex and cell line specific. These features may be relevant to discriminate stage dependent TGF-β functions for the design of efficient TGF-β directed therapy in liver cancer.

Characterization of a multi-axis ion chamber array.

PubMed

Simon, Thomas A; Kozelka, Jakub; Simon, William E; Kahler, Darren; Li, Jonathan; Liu, Chihray

2010-11-01

The aim of this work was to characterize a multi-axis ion chamber array (IC PROFILER; Sun Nuclear Corporation, Melbourne, FL, USA) that has the potential to simplify the acquisition of LINAC beam data. The IC PROFILER (or panel) measurement response was characterized with respect to radiation beam properties, including dose, dose per pulse, pulse rate frequency (PRF), and energy. Panel properties were also studied, including detector-calibration stability, power-on time, backscatter dependence, and the panel's agreement with water tank measurements [profiles, fractional depth dose (FDD), and output factors]. The panel's relative deviation was typically within (+/-) 1% of an independent (or nominal) response for all properties that were tested. Notable results were (a) a detectable relative field shape change of approximately 1% with linear accelerator PRF changes; (b) a large range in backscatter thickness had a minimal effect on the measured dose distribution (typically less than 1%); (c) the error spread in profile comparison between the panel and scanning water tank (Blue Phantom, CC13; IBA Schwarzenbruck, DE) was approximately (+/-) 0.75%. The ability of the panel to accurately reproduce water tank profiles, FDDs, and output factors is an indication of its abilities as a dosimetry system. The benefits of using the panel versus a scanning water tank are less setup time and less error susceptibility. The same measurements (including device setup and breakdown) for both systems took 180 min with the water tank versus 30 min with the panel. The time-savings increase as the measurement load is increased.

Attention reduces spatial uncertainty in human ventral temporal cortex.

PubMed

Kay, Kendrick N; Weiner, Kevin S; Grill-Spector, Kalanit

2015-03-02

Ventral temporal cortex (VTC) is the latest stage of the ventral "what" visual pathway, which is thought to code the identity of a stimulus regardless of its position or size [1, 2]. Surprisingly, recent studies show that position information can be decoded from VTC [3-5]. However, the computational mechanisms by which spatial information is encoded in VTC are unknown. Furthermore, how attention influences spatial representations in human VTC is also unknown because the effect of attention on spatial representations has only been examined in the dorsal "where" visual pathway [6-10]. Here, we fill these significant gaps in knowledge using an approach that combines functional magnetic resonance imaging and sophisticated computational methods. We first develop a population receptive field (pRF) model [11, 12] of spatial responses in human VTC. Consisting of spatial summation followed by a compressive nonlinearity, this model accurately predicts responses of individual voxels to stimuli at any position and size, explains how spatial information is encoded, and reveals a functional hierarchy in VTC. We then manipulate attention and use our model to decipher the effects of attention. We find that attention to the stimulus systematically and selectively modulates responses in VTC, but not early visual areas. Locally, attention increases eccentricity, size, and gain of individual pRFs, thereby increasing position tolerance. However, globally, these effects reduce uncertainty regarding stimulus location and actually increase position sensitivity of distributed responses across VTC. These results demonstrate that attention actively shapes and enhances spatial representations in the ventral visual pathway. Copyright © 2015 Elsevier Ltd. All rights reserved.

Attention reduces spatial uncertainty in human ventral temporal cortex

PubMed Central

Kay, Kendrick N.; Weiner, Kevin S.; Grill-Spector, Kalanit

2014-01-01

SUMMARY Ventral temporal cortex (VTC) is the latest stage of the ventral ‘what’ visual pathway, which is thought to code the identity of a stimulus regardless of its position or size [1, 2]. Surprisingly, recent studies show that position information can be decoded from VTC [3–5]. However, the computational mechanisms by which spatial information is encoded in VTC are unknown. Furthermore, how attention influences spatial representations in human VTC is also unknown because the effect of attention on spatial representations has only been examined in the dorsal ‘where’ visual pathway [6–10]. Here we fill these significant gaps in knowledge using an approach that combines functional magnetic resonance imaging and sophisticated computational methods. We first develop a population receptive field (pRF) model [11, 12] of spatial responses in human VTC. Consisting of spatial summation followed by a compressive nonlinearity, this model accurately predicts responses of individual voxels to stimuli at any position and size, explains how spatial information is encoded, and reveals a functional hierarchy in VTC. We then manipulate attention and use our model to decipher the effects of attention. We find that attention to the stimulus systematically and selectively modulates responses in VTC, but not early visual areas. Locally, attention increases eccentricity, size, and gain of individual pRFs, thereby increasing position tolerance. However, globally, these effects reduce uncertainty regarding stimulus location and actually increase position sensitivity of distributed responses across VTC. These results demonstrate that attention actively shapes and enhances spatial representations in the ventral visual pathway. PMID:25702580

Influence of platelet rich fibrin on post-extraction socket healing: A clinical and radiographic study.

PubMed

Alzahrani, Ahmed Abdullah; Murriky, Afraa; Shafik, Sami

2017-10-01

The aim of this study was to evaluate clinically and radiographically, extraction socket healing using autologous platelet rich fibrin (PRF). Twenty-four subjects needing single tooth simple extractions were selected. Twenty-four extraction sockets were divided into test group (PRF, n = 12) and control group (blood clot, n = 12). PRF was prepared with blood drawn from individuals after extraction using standard technique. PRF was placed in test group sockets followed by pressure application and figure 8 sutures. Sockets in control group were allowed to heal in the presence of blood clot and received a figure 8 suture. Ridge width was assessed using cast analysis with the help of acrylic stent and a pair of calipers. Radiographic analysis of socket surface area was performed using computer graphic software program. The clinical follow up assessments were performed at 1, 4 and 8 weeks. Collected data was assessed using ANOVA and multiple comparisons test. Subjects were aged between 25 and 50 (mean 37.8) years, including 15 females. The mean horizontal ridge width for sockets in the test group were 11.70 ± 2.37 mm, 11.33 ± 2.30 mm and 10.97 ± 2.33 mm at 1, 4 and 8 weeks respectively. Ridge width proportions were significantly higher among test group as compared to control group between baseline to 4 and 8 weeks respectively. The mean radiographic bone fill (RBF) percentage in the test group, was 74.05 ± 1.66%, 81.54 ± 3.33% and 88.81 ± 1.53% at 1, 4 and 8 weeks respectively. The mean RBF was significantly higher in the test group than control group at all time intervals. The study outcomes demonstrate that the use of PRF accelerate socket wound healing after tooth extraction as noticed by increased bone fill and reduced alveolar bone width resorption using clinical and radiographic methods.

Production of infectious dromedary camel hepatitis E virus by a reverse genetic system: Potential for zoonotic infection.

PubMed

Li, Tian-Cheng; Zhou, Xianfeng; Yoshizaki, Sayaka; Ami, Yasushi; Suzaki, Yuriko; Nakamura, Tomofumi; Takeda, Naokazu; Wakita, Takaji

2016-12-01

The pathogenicity, epidemiology and replication mechanism of dromedary camel hepatitis E virus (DcHEV), a novel hepatitis E virus (HEV), has been unclear. Here we used a reverse genetic system to produce DcHEV and examined the possibility of zoonotic infection. Capped genomic RNA derived from a synthetic DcHEV cDNA was transfected into human hepatocarcinoma cells PLC/PRF/5. The DcHEV capsid protein and RNA were detected by an enzyme-linked immunosorbent assay (ELISA) or RT-qPCR. A neutralization test for DcHEV was carried out by using antisera against HEV-like particles. DcHEV was used to inoculate two cynomolgus monkeys to examine the potential for cross-species infection. The transfection of PLC/PRF/5 cells with capped DcHEV RNA resulted in the production of infectious DcHEV. The genome sequence analysis demonstrated that both nucleotide and amino acid changes accumulated during the passages in PLC/PRF/5 cells. The cynomolgus monkeys showed serological signs of infection when DcHEV was intravenously inoculated. DcHEV was neutralized by not only anti-DcHEV-LPs antibody, but also anti-genotype 1 (G1), G3 and G4 HEV-LPs antibodies. Moreover, the monkeys immunized with DcHEV escaped the G3 HEV challenge, indicating that the serotype of DcHEV is similar to those of other human HEVs. Infectious DcHEV was produced using a reverse genetic system and propagated in PLC/PRF/5 cells. The antigenicity and immunogenicity of DcHEV are similar to those of G1, G3 and G4 HEV. DcHEV was experimentally transmitted to primates, demonstrating the possibility of a zoonotic infection by DcHEV. Dromedary camel hepatitis E virus (DcHEV) was produced by a reverse genetic system and grows well in PLC/PRF/5 cells. Cynomolgus monkeys experimentally infected with DcHEV indicated serological signs of infection, suggesting that DcHEV has the potential to cause zoonotic HEV infection. Copyright © 2016 European Association for the Study of the Liver. Published by Elsevier B.V. All rights reserved.

Conventional Radiofrequency Thermocoagulation vs Pulsed Radiofrequency Neuromodulation of Ganglion Impar in Chronic Perineal Pain of Nononcological Origin.

PubMed

Usmani, Hammad; Dureja, G P; Andleeb, Roshan; Tauheed, Nazia; Asif, Naiyer

2018-01-10

Chronic nononcological perineal pain has been effectively managed by ganglion Impar block. Chemical neurolysis, cryoablation, and radiofrequency ablation have been the accepted methods of blockade. Recently, pulsed radiofrequency, a novel variant of conventional radiofrequency, has been used for this purpose. This was a prospective, randomized, double-blind study. Two different interventional pain management centers in India. To compare the efficacy of conventional radiofrequency and pulsed radiofrequency for gangliom Impar block. The patients were randomly allocated to one of two groups. In the conventional radiofrequency (CRF) group (N = 34), conventional radiofrequency ablation was done, and in the PRF pulsed radiofrequency (PRF) group (N = 31), pulsed radiofrequency ablation was done. After informed and written consent, fluoroscopy-guided ganglion Impar block was performed through the first intracoccygeal approach. The extent of pain relief was assessed by visual analog scale (VAS) at 24 hours, and at the first, third, and sixth weeks following the intervention. A questionnaire to evaluate subjective patient satisfaction was also used at each follow-up visit. In the CRF group, the mean VAS score decreased significantly from the baseline value at each follow-up visit. But in the PRF group, this decrease was insignificant except at 24-hour follow-up. Intergroup comparison also showed significantly better pain relief in the CRF group as compared with the PRF group. At the end of follow-up, 28 patients (82%) in the CRF group and four patients (13%) in the PRF group had excellent results, as assessed by the subjective patient satisfaction questionnaire. There was no complication in any patient of either study group, except for short-lived infection at the site of skin puncture in a few. Ganglion Impar block by conventional radiofrequency provided a significantly better quality of pain relief with no major side effects in patients with chronic nononcological perineal pain as compared with pulsed radiofrequency. The short-term follow-up period of only six weeks was a major drawback associated with this study. © 2018 American Academy of Pain Medicine. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com

Platelet rich fibrin combined with decalcified freeze-dried bone allograft for the treatment of human intrabony periodontal defects: a randomized split mouth clinical trail.

PubMed

Agarwal, Ashish; Gupta, Narinder Dev; Jain, Avikal

2016-01-01

Polypeptide growth factors of platelet rich fibrin (PRF) have the potential to regenerate periodontal tissues. Osteoinductive property of demineralized freeze-dried bone allograft (DFDBA) has been successfully utilized in periodontal regeneration. The aim of the present randomized, split mouth, clinical trial was to determine the additive effects of PRF with a DFDBA in the treatment of human intrabony periodontal defects. Sixty interproximal infrabony defects in 30 healthy, non-smoker patients diagnosed with chronic periodontitis were randomly assigned to PRF/DFDBA group or the DFDBA/saline. Clinical [pocket depth (PD), clinical attachment level (CAL) and gingival recession (REC)] and radiographic (bone fill, defect resolution and alveolar crest resorption) measurements were made at baseline and at a 12-month evaluation. Compared with baseline, 12-month results indicated that both treatment modalities resulted in significant changes in all clinical and radiographic parameters. However, the PRP/DFDBA group exhibited statistically significantly greater changes compared with the DFDBA/saline group in PD (4.15 ± 0.84 vs 3.60 ± 0.51 mm), CAL (3.73 ± 0.74 vs 2.61 ± 0.68 mm), REC (0.47 ± 0.56 vs 1.00 ± 0.61 mm), bone fill (3.50 ± 0.67 vs 2.49 ± 0.64 mm) and defect resolution (3.73 ± 0.63 vs 2.75 ± 0.57 mm). Observations indicate that a combination of PRF and DFDBA is more effective than DFDBA with saline for the treatment of infrabony periodontal defects.

Comparative Evaluation of Platelet-Rich Fibrin Biomaterial and Open Flap Debridement in the Treatment of Two and Three Wall Intrabony Defects

PubMed Central

Ajwani, Himanshu; Shetty, Sharath; Gopalakrishnan, Dharmarajan; Kathariya, Rahul; Kulloli, Anita; Dolas, R S; Pradeep, A R

2015-01-01

Background: Platelet-rich concentrates are the most widely used regenerative biomaterials. Stimulation and acceleration of soft and hard tissue healing are due to local and continuous delivery of growth factors and proteins, mimicking the needs of the physiological wound healing and reparative tissue processes. This article aims to evaluate the clinical efficacy of open flap debridement (OFD) with or without platelet-rich fibrin (PRF) in the treatment of intrabony defects. Materials and Methods: Twenty subjects with forty intrabony defects were treated with either autologous PRF with open-flap debridement (test, n = 20) or open-flap debridement alone (control, n = 20). Soft tissue parameters included: Plaque index, sulcus bleeding index, probing depth, relative attachment level and gingival marginal level (GML). The hard tissue parameters included-distances from: Cement enamel junction to the base of the defect (CEJ-BOD): Alveolar crest to the base of the defect (AC-BOD): And CEJ to AC. The parameters were recorded at baseline and at 9 months postoperatively calculated using standardized radiographs by image-analysis software. Results: Statistically significant (0.005*) intragroup improvements were seen with all the hard and soft parameters in both test and control groups, except for GML. Statistically significant improvements were seen with the mean defect fill (CEJ-BOD and AC-BOD) (P = 0.003*) when intergroup comparisons were made. Conclusions: Adjunctive use of PRF with OFD significantly improves defect fill when compared to OFD alone. PRF has consistently been showing regenerative potential; it is simple, easy and inexpensive biomaterial compared with bone grafts. PMID:25954068

Pulsed radiofrequency for chronic intractable lumbosacral radicular pain: a six-month cohort study.

PubMed

Van Boxem, Koen; de Meij, Nelleke; Kessels, Alfons; Van Kleef, Maarten; Van Zundert, Jan

2015-06-01

There is little evidence concerning the medical management of lumbosacral radicular pain. The prognosis for patients suffering pain for more than 3 months is poor. Pulsed radiofrequency (PRF) treatment of the dorsal root ganglion (DRG) has been suggested as a minimally invasive treatment. We studied the effect on pain and quality of life of PRF treatment of the DRG in patients with chronic, severe lumbosacral radicular pain. Patients with lumbosacral radicular pain were screened to select a homogeneous population. PRF treatment of the DRG was performed at L5 or S1. Evaluation was carried out at 6 weeks, 3 months, and 6 months. Pain reduction and "fully recovered" or "much improvement," in terms of the global perceived effect, were the primary outcomes. Quality of life (RAND-36), disability (Oswestry Disability Index), and the neuropathic pain scales leeds assessment of neuropathic symptoms and signs (LANSS) and DN4 were registered at each time point. Medication use was scored with the Medication Quantification Scale. Out of 461 screened patients, 65 were included. According to the intention to treat analysis, clinical success was achieved in 56.9%, 52.3%, and 55.4% of the patients at respectively 6 weeks, 3 months, and 6 months. DN4, Oswestry Disability Index and physical component for the RAND-36 quality of life improved significantly while the mental component remained unchanged. The number of patients on opioids was reduced. PRF treatment of the DRG may be considered for patients with chronic, severe lumbosacral radicular pain refractory to conventional medical management. Wiley Periodicals, Inc.

A loop 2 cytidine-stem 1 minor groove interaction as a positive determinant for pseudoknot-stimulated -1 ribosomal frameshifting.

PubMed

Cornish, Peter V; Hennig, Mirko; Giedroc, David P

2005-09-06

The molecular determinants of stimulation of -1 programmed ribosomal frameshifting (-1 PRF) by RNA pseudoknots are poorly understood. Sugarcane yellow leaf virus (ScYLV) encodes a 28-nt mRNA pseudoknot that promotes -1 PRF between the P1 (protease) and P2 (polymerase) genes in plant luteoviruses. The solution structure of the ScYLV pseudoknot reveals a well ordered loop 2 (L2) that exhibits continuous stacking of A20 through C27 in the minor groove of the upper stem 1 (S1), with C25 flipped out of the triple-stranded stack. Five consecutive triple base pairs flank the helical junction where the 3' nucleotide of L2, C27, adopts a cytidine 27 N3-cytidine 14 2'-OH hydrogen bonding interaction with the C14-G7 base pair. This interaction is isosteric with the adenosine N1-2'-OH interaction in the related mRNA from beet western yellows virus (BWYV); however, the ScYLV and BWYV mRNA structures differ in their detailed L2-S1 hydrogen bonding and L2 stacking interactions. Functional analyses of ScYLV/BWYV chimeric pseudoknots reveal that the ScYLV RNA stimulates a higher level of -1 PRF (15 +/- 2%) relative to the BWYV pseudoknot (6 +/- 1%), a difference traced largely to the identity of the 3' nucleotide of L2 (C27 vs. A25 in BWYV). Strikingly, C27A ScYLV RNA is a poor frameshift stimulator (2.0%) and is destabilized by approximately 1.5 kcal x mol(-1) (pH 7.0, 37 degrees C) with respect to the wild-type pseudoknot. These studies establish that the precise network of weak interactions nearest the helical junction in structurally similar pseudoknots make an important contribution to setting the frameshift efficiency in mRNAs.

A loop 2 cytidine-stem 1 minor groove interaction as a positive determinant for pseudoknot-stimulated –1 ribosomal frameshifting

PubMed Central

Cornish, Peter V.; Hennig, Mirko; Giedroc, David P.

2005-01-01

The molecular determinants of stimulation of –1 programmed ribosomal frameshifting (–1 PRF) by RNA pseudoknots are poorly understood. Sugarcane yellow leaf virus (ScYLV) encodes a 28-nt mRNA pseudoknot that promotes –1 PRF between the P1 (protease) and P2 (polymerase) genes in plant luteoviruses. The solution structure of the ScYLV pseudoknot reveals a well ordered loop 2 (L2) that exhibits continuous stacking of A20 through C27 in the minor groove of the upper stem 1 (S1), with C25 flipped out of the triple-stranded stack. Five consecutive triple base pairs flank the helical junction where the 3′ nucleotide of L2, C27, adopts a cytidine 27 N3-cytidine 14 2′-OH hydrogen bonding interaction with the C14-G7 base pair. This interaction is isosteric with the adenosine N1–2′-OH interaction in the related mRNA from beet western yellows virus (BWYV); however, the ScYLV and BWYV mRNA structures differ in their detailed L2–S1 hydrogen bonding and L2 stacking interactions. Functional analyses of ScYLV/BWYV chimeric pseudoknots reveal that the ScYLV RNA stimulates a higher level of –1 PRF (15 ± 2%) relative to the BWYV pseudoknot (6 ± 1%), a difference traced largely to the identity of the 3′ nucleotide of L2 (C27 vs. A25 in BWYV). Strikingly, C27A ScYLV RNA is a poor frameshift stimulator (2.0%) and is destabilized by ≈1.5 kcal·mol–1 (pH 7.0, 37°C) with respect to the wild-type pseudoknot. These studies establish that the precise network of weak interactions nearest the helical junction in structurally similar pseudoknots make an important contribution to setting the frameshift efficiency in mRNAs. PMID:16123125

Autologus Platelet Rich Fibrin aided Revascularization of an immature, non-vital permanent tooth with apical periodontitis: A case report.

PubMed

Jadhav, Ganesh Ranganath; Shah, Dipali; Raghvendra, Srinidhi Surya

2015-01-01

Caries or trauma induced non-vital immature permanent tooth with blunderbuss, thin root which are very common among childrens are corrected using regenerative endodontic (revascularization) procedures. In the presented case, a 16-year-old boy reported with chief complaint of pain in maxillary left central incisor (Tooth #21). Tooth #21 showed grade III mobility, draining labial sinus, and short blunderbuss root with diffuse periapical radiolucency. Patient was explained the treatment plan and written informed consent was taken. Platelet rich fibrin (PRF) was prepared according to standard protocol. Autologous PRF was carried to the apical portion of the root canal after inducing revascularization. Access opening was double sealed with MTA and resin modified glass ionomer cement (RMGI). Baseline, 12 month and 18 month follow-up intraoral radiographs were taken. Clinically case was asymptomatic with complete resolution of intraoral sinus. Periapical healing, apical closure, root lengthening and dentinal wall thickening were uneventful. Thus PRF supplementation hastens the predictability and rate of revascularization in non-vital immature permanent teeth.

Evaluation of the effects of platelet-rich fibrin and piezosurgery on outcomes after removal of ımpacted mandibular third molars.

PubMed

Bilginaylar, K; Uyanik, L O

2016-07-01

We compared postoperative outcomes after the removal of 80 impacted mandibular third molars in 59 patients. In the control group, osteotomies were done with traditional burs (n=20). The second group had traditional osteotomies and platelet-rich fibrin (PRF) placed into the socket of the extracted tooth (n=20). The third group had piezosurgery (n=20), and the fourth had piezosurgery and PRF placed in the extraction socket (n=20). Baseline variables were assessed preoperatively and included pain, the number of analgesics taken, trismus, and swelling. These were also assessed on postoperative days 1, 2, 3, and 7. There was a significant reduction (p<0.05) in pain on days 1, 2, and 3, and in the number of analgesics taken on days 2 and 3 in both PRF groups. However, in the piezosurgery alone group this was the case only on day 3. There was no significant difference in swelling and trismus between the control and other groups. Copyright © 2016 The British Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.

Can responses to basic non-numerical visual features explain neural numerosity responses?

PubMed

Harvey, Ben M; Dumoulin, Serge O

2017-04-01

Humans and many animals can distinguish between stimuli that differ in numerosity, the number of objects in a set. Human and macaque parietal lobes contain neurons that respond to changes in stimulus numerosity. However, basic non-numerical visual features can affect neural responses to and perception of numerosity, and visual features often co-vary with numerosity. Therefore, it is debated whether numerosity or co-varying low-level visual features underlie neural and behavioral responses to numerosity. To test the hypothesis that non-numerical visual features underlie neural numerosity responses in a human parietal numerosity map, we analyze responses to a group of numerosity stimulus configurations that have the same numerosity progression but vary considerably in their non-numerical visual features. Using ultra-high-field (7T) fMRI, we measure responses to these stimulus configurations in an area of posterior parietal cortex whose responses are believed to reflect numerosity-selective activity. We describe an fMRI analysis method to distinguish between alternative models of neural response functions, following a population receptive field (pRF) modeling approach. For each stimulus configuration, we first quantify the relationships between numerosity and several non-numerical visual features that have been proposed to underlie performance in numerosity discrimination tasks. We then determine how well responses to these non-numerical visual features predict the observed fMRI responses, and compare this to the predictions of responses to numerosity. We demonstrate that a numerosity response model predicts observed responses more accurately than models of responses to simple non-numerical visual features. As such, neural responses in cognitive processing need not reflect simpler properties of early sensory inputs. Copyright © 2017 Elsevier Inc. All rights reserved.

Anisotropic imaging performance in indirect x-ray imaging detectors

DOE Office of Scientific and Technical Information (OSTI.GOV)

Badano, Aldo; Kyprianou, Iacovos S.; Sempau, Josep

We report on the variability in imaging system performance due to oblique x-ray incidence, and the associated transport of quanta (both x rays and optical photons) through the phosphor, in columnar indirect digital detectors. The analysis uses MANTIS, a combined x-ray, electron, and optical Monte Carlo transport code freely available. We describe the main features of the simulation method and provide some validation of the phosphor screen models considered in this work. We report x-ray and electron three-dimensional energy deposition distributions and point-response functions (PRFs), including optical spread in columnar phosphor screens of thickness 100 and 500 {mu}m, for 19,more » 39, 59, and 79 keV monoenergetic x-ray beams incident at 0 deg., 10 deg., and 15 deg. . In addition, we present pulse-height spectra for the same phosphor thickness, x-ray energies, and angles of incidence. Our results suggest that the PRF due to the phosphor blur is highly nonsymmetrical, and that the resolution properties of a columnar screen in a tomographic, or tomosynthetic imaging system varies significantly with the angle of x-ray incidence. Moreover, we find that the noise due to the variability in the number of light photons detected per primary x-ray interaction, summarized in the information or Swank factor, is somewhat independent of thickness and incidence angle of the x-ray beam. Our results also suggest that the anisotropy in the PRF is not less in screens with absorptive backings, while the noise introduced by variations in the gain and optical transport is larger. Predictions from MANTIS, after additional validation, can provide the needed understanding of the extent of such variations, and eventually, lead to the incorporation of the changes in imaging performance with incidence angle into the reconstruction algorithms for volumetric x-ray imaging systems.« less

A novel self-micro-emulsifying delivery system (SMEDS) formulation significantly improves the fasting absorption of EPA and DHA from a single dose of an omega-3 ethyl ester concentrate.

PubMed

Qin, Yan; Nyheim, Hilde; Haram, Else Marie; Moritz, Joseph M; Hustvedt, Svein Olaf

2017-10-16

Absorption of EPA and DHA from Omega-3-acid ethyl ester (EE) concentrate supplements occurs most efficiently when taken in context of a fatty meal; adequate fat intake is required to release bile salts that emulsify and pancreatic enzymes that digest omega-3-containing lipids in the intestine. Current guidelines recommend reduction in fat intake and therefore there is a need to optimize the absorption of Omega-3 in those consuming low-fat or no-fat meals. To this end, BASF has developed an Absorption Acceleration Technology, a novel self-micro-emulsifying delivery system (SMEDS) formulation of highly concentrated Omega-3-acid EE which enables rapid emulsification and microdroplet formation upon entering the aqueous environment of the gut therefore enhances the absorption. Two separate single dose, crossover studies were conducted to determine the relative bioavailability of omega-3-acid EE concentrate, either as a novel SMEDS formulation (PRF-021) or as control, in healthy fasted male and female adults at two dose levels (Study 1 "low dose": 630 mg EPA + DHA in PRF-021 vs. 840 mg EPA + DHA in control; Study 2 "high dose": 1680 mg EPA + DHA in PRF-021 vs. 3360 mg EPA + DHA in control). Blood samples were collected immediately before supplementation and at defined time intervals for 48 h. Plasma concentration of total EPA and DHA were determined for pharmacokinetic analysis, area under the curve (AUC) and maximum observed concentration (C max ) was determined. Total EPA plus DHA absorption from SMEDS formulation PRF-021 were 6.4 and 11.5 times higher compared to control in low- and high-dose studies respectively, determined as the ratio of baseline corrected, dose normalized AUC 0-24h of PRF-021 over that of control. EPA and DHA individually showed differing levels of enhancement: the AUC 0-24h ratio for EPA was 23.8 and 25.7 in low and high dose studies, respectively, and the AUC 0-24h ratio for DHA was 3.6 and 5.6 in low and high dose studies, respectively. C max was also increased for both EPA and DHA 2.7- to 9.2-fold. PRF-021 is a novel SMEDS formulation of Omega-3-acid EE demonstrating a marked improvement in absorption of a single dose of EPA and DHA EE under fasted conditions. This allows adequate absorption of Omega-3 from the supplement without the requirement of a high-fat meal.

Characterization of a multi-axis ion chamber array

DOE Office of Scientific and Technical Information (OSTI.GOV)

Simon, Thomas A.; Kozelka, Jakub; Simon, William E.

Purpose: The aim of this work was to characterize a multi-axis ion chamber array (IC PROFILER; Sun Nuclear Corporation, Melbourne, FL USA) that has the potential to simplify the acquisition of LINAC beam data. Methods: The IC PROFILER (or panel) measurement response was characterized with respect to radiation beam properties, including dose, dose per pulse, pulse rate frequency (PRF), and energy. Panel properties were also studied, including detector-calibration stability, power-on time, backscatter dependence, and the panel's agreement with water tank measurements [profiles, fractional depth dose (FDD), and output factors]. Results: The panel's relative deviation was typically within ({+-}) 1% ofmore » an independent (or nominal) response for all properties that were tested. Notable results were (a) a detectable relative field shape change of {approx}1% with linear accelerator PRF changes; (b) a large range in backscatter thickness had a minimal effect on the measured dose distribution (typically less than 1%); (c) the error spread in profile comparison between the panel and scanning water tank (Blue Phantom, CC13; IBA Schwarzenbruck, DE) was approximately ({+-}) 0.75%. Conclusions: The ability of the panel to accurately reproduce water tank profiles, FDDs, and output factors is an indication of its abilities as a dosimetry system. The benefits of using the panel versus a scanning water tank are less setup time and less error susceptibility. The same measurements (including device setup and breakdown) for both systems took 180 min with the water tank versus 30 min with the panel. The time-savings increase as the measurement load is increased.« less

A comparative study of the regenerative effect of sinus bone grafting with platelet-rich fibrin-mixed Bio-Oss® and commercial fibrin-mixed Bio-Oss®: an experimental study.

PubMed

Xuan, Feng; Lee, Chun-Ui; Son, Jeong-Seog; Jeong, Seung-Mi; Choi, Byung-Ho

2014-06-01

Anorganic bovine bone (Bio-Oss®) particles are one of the most popular grafting materials. The particles are often mixed with platelet-rich fibrin (PRF) or a commercial fibrin (Tisseel®) to form a mouldable graft material. The objective of this study was to compare the potentials of PRF-mixed Bio-Oss® and Tisseel®-mixed Bio-Oss® to enhance bone regeneration in a canine sinus model. Six mongrel dogs were used in this study. After elevating the sinus membrane in both maxillary sinus cavities, an implant was placed into the sinus cavity. In one of the sinus cavities, the PRF/Bio-Oss® composite was grafted, and the Tisseel®/Bio-Oss® composite was grafted in the other sinus cavity. After a 6 month healing period, bone formation in the graft sites and bone-implant contact were evaluated. The mean osseointegration rate was 43.5 ± 12.4% and new bone formation rate 41.8 ± 5.9% in the PRF/Bio-Oss® composite sites. In the Tisseel®/Bio-Oss® composite sites they were 30.7 ± 7.9% and 31.3 ± 6.4%. There were statistically significant differences between the groups. The findings from this study suggest that when platelet-rich fibrin is used as an adjunct to Bio-Oss® particles for bone augmentation in the maxillary sinus, bone formation in the graft sites is significantly greater than when Tisseel® is used. Copyright © 2013 European Association for Cranio-Maxillo-Facial Surgery. Published by Elsevier Ltd. All rights reserved.

An Innovative Regenerative Endodontic Procedure Using Leukocyte and Platelet-rich Fibrin Associated with Apical Surgery: A Case Report.

PubMed

Pinto, Nelson; Harnish, Alexandra; Cabrera, Carolina; Andrade, Catherine; Druttman, Tony; Brizuela, Claudia

2017-11-01

Regenerative endodontic procedures (REPs) associated with apical surgery could represent an alternative treatment strategy for patients whose teeth present incomplete root formation and extensive apical lesions. Leukocyte platelet-rich fibrin (L-PRF) has potential benefits in REPs; it could promote apical root formation and optimal bone healing. The aim of this case report was to describe innovative regenerative endodontic therapy using L-PRF in the root canal and an extensive apical lesion in an immature tooth with dens invaginatus and asymptomatic apical periodontitis. A healthy 20-year-old woman was referred to the dental clinic of the Universidad de Los Andes, Santiago, Chile, for endodontic treatment in tooth # 22 with incomplete root development and an extensive apical lesion. The diagnosis was asymptomatic apical periodontitis associated with dens invaginatus type II. The patient was treated with an innovative approach using L-PRF in REPs associated with apical surgery. Follow-ups were performed at 6 months and 1 year later. They included periapical radiographs, cone-beam computed tomographic imaging, sensitivity, and vitality tests. The clinical evaluations performed at 6 months and 1 year revealed an absence of symptoms. The radiographic evaluations showed that the apical lesion was resolved. The cone-beam images indicated that the root length increased and the walls had thickened. The sensitivity tests were positive, and the laser Doppler flowmetry showed positive blood flow after 1 year. The success of the results in this case report indicate that L-PRF can be used as a complement in apical surgery and REPs and could provide an innovative alternative treatment strategy for complex clinical cases like these. Copyright © 2017 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

To assess the efficacy of socket plug technique using platelet rich fibrin with or without the use of bone substitute in alveolar ridge preservation: a prospective randomised controlled study.

PubMed

Girish Kumar, N; Chaudhary, Rupanzal; Kumar, Ish; Arora, Srimathy S; Kumar, Nilesh; Singh, Hem

2018-06-01

The purpose of this study is to evaluate the efficacy of Platelet Rich Fibrin (PRF) as a socket plug with or without use of Plaster of Paris (POP) as bone substitute to preserve the alveolar ridge post-extraction. A prospective randomised single blind controlled study, was conducted for 18 months from November 2014 to May 2016 on 48 patients requiring extraction. All teeth were extracted atraumatically using periotomes and luxators without raising mucoperiosteal flap. Sockets were randomly allotted to groups A, B and C. Group A sockets were chosen as control, where figure of eight suture was placed. In group B sockets, PRF obtained by centrifugation was used as a socket plug and stabilised with figure of eight suture. Group C sockets were filled with POP and then covered with PRF. The socket was then closed with a figure of eight suture. Patients were informed of need for 6 months follow-up. Ninety sockets in 48 patients were subjected to our study. We found that results in the sockets where we have grafted POP showed better ridge preservation and post-operative comfort even though the difference in ridge resorption between the three groups was not statistically significant. Powered by Editorial Manager® and ProduXion Manager® from the Aries Systems Corporation. Atraumatic extraction may minimise the post-operative pain and discomfort to patient as well as the post-extraction alveolar height and width changes. The use of PRF and/or bone substitute even though clinically contributes to better post-operative healing and minimal loss of alveolar width and height, the values were not statistically significant.

Assessment of thermal effects of interstitial laser phototherapy on mammary tumors using proton resonance frequency method

PubMed Central

Le, Kelvin; Li, Xiaosong; Figueroa, Daniel; Towner, Rheal A.; Garteiser, Philippe; Saunders, Debra; Smith, Nataliya; Liu, Hong; Hode, Tomas; Nordquist, Robert E.; Chen, Wei R.

2011-01-01

Laser immunotherapy (LIT) uses a synergistic approach to treat cancer systemically through local laser irradiation and immunological stimulation. Currently, LIT utilizes dye-assisted noninvasive laser irradiation to achieve selective photothermal interaction. However, LIT faces difficulties treating deeper tumors or tumors with heavily pigmented overlying skin. To circumvent these barriers, we use interstitial laser irradiation to induce the desired photothermal effects. The purpose of this study is to analyze the thermal effects of interstitial irradiation using proton resonance frequency (PRF). An 805-nm near-infrared laser with an interstitial cylindrical diffuser was used to treat rat mammary tumors. Different power settings (1.0, 1.25, and 1.5 W) were applied with an irradiation duration of 10 min. The temperature distributions of the treated tumors were measured by a 7 T magnetic resonance imager using PRF. We found that temperature distributions in tissue depended on both laser power and time settings, and that variance in tissue composition has a major influence in temperature elevation. The temperature elevations measured during interstitial laser irradiation by PRF and thermocouple were consistent, with some variations due to tissue composition and the positioning of the thermocouple's needle probes. Our results indicated that, for a tissue irradiation of 10 min, the elevation of rat tumor temperature ranged from 8 to 11°C for 1 W and 8 to 15°C for 1.5 W. This is the first time a 7 T magnetic resonance imager has been used to monitor interstitial laser irradiation via PRF. Our work provides a basic understanding of the photothermal interaction needed to control the thermal damage inside a tumor using interstitial laser treatment. Our work may lead to an optimal protocol for future cancer treatment using interstitial phototherapy in conjunction with immunotherapy. PMID:22191937

Platelet rich fibrin (Prf) and β-tricalcium phosphate with coronally advanced flap for the management of grade-II furcation defect.

PubMed

Sambhav, Jain; Rohit, Rai; Ranjana, Mohan; Shalabh, Mehrotra

2014-07-01

Multirooted teeth offer unique and challenging problems due to the furcation area, creates situations in which routine periodontal procedures are somewhat limited and special procedures are generally required. The present case was showing the management of grade II furcation defect by platelet rich fibrin (PRF) and β-Tricalcium phosphate with coronally advanced flap. Platelet rich fibrin and β-Tricalcium phosphate with coronally advanced flap have been shown to be a promising and successful approach for the treatment of furcation defect. Its gaining clinical attachment significantly manages both the gingival recession and furcation involvement simultaneously.

Iron bromide vapor laser

NASA Astrophysics Data System (ADS)

Sukhanov, V. B.; Shiyanov, D. V.; Trigub, M. V.; Dimaki, V. A.; Evtushenko, G. S.

2016-03-01

We have studied the characteristics of a pulsed gas-discharge laser on iron bromide vapor generating radiation with a wavelength of 452.9 nm at a pulse repetition frequency (PRF) of 5-30 kHz. The maximum output power amounted to 10 mW at a PRF within 5-15 kHz for a voltage of 20-25 kV applied to electrodes of the discharge tube. Addition of HBr to the medium produced leveling of the radial profile of emission. Initial weak lasing at a wavelength of 868.9 nm was observed for the first time, which ceased with buildup of the main 452.9-nm line.

Solid-Body Fuse Developed for High- Voltage Space Power Missions

NASA Technical Reports Server (NTRS)

Dolce, James L.; Baez, Anastacio N.

2001-01-01

AEM Incorporated has completed the development, under a NASA Glenn Research Center contract, of a solid-body fuse for high-voltage power systems of satellites and spacecraft systems. High-reliability fuses presently defined by MIL-PRF-23419 do not meet the increased voltage and amperage requirements for the next generation of spacecraft. Solid-body fuses exhibit electrical and mechanical attributes that enable these fuses to perform reliably in the vacuum and high-vibration and -shock environments typically present in spacecraft applications. The construction and screening techniques for solid-body fuses described by MIL-PRF-23419/12 offer an excellent roadmap for the development of high-voltage solid-body fuses.

High speed micromachining with high power UV laser

NASA Astrophysics Data System (ADS)

Patel, Rajesh S.; Bovatsek, James M.

2013-03-01

Increasing demand for creating fine features with high accuracy in manufacturing of electronic mobile devices has fueled growth for lasers in manufacturing. High power, high repetition rate ultraviolet (UV) lasers provide an opportunity to implement a cost effective high quality, high throughput micromachining process in a 24/7 manufacturing environment. The energy available per pulse and the pulse repetition frequency (PRF) of diode pumped solid state (DPSS) nanosecond UV lasers have increased steadily over the years. Efficient use of the available energy from a laser is important to generate accurate fine features at a high speed with high quality. To achieve maximum material removal and minimal thermal damage for any laser micromachining application, use of the optimal process parameters including energy density or fluence (J/cm2), pulse width, and repetition rate is important. In this study we present a new high power, high PRF QuasarR 355-40 laser from Spectra-Physics with TimeShiftTM technology for unique software adjustable pulse width, pulse splitting, and pulse shaping capabilities. The benefits of these features for micromachining include improved throughput and quality. Specific example and results of silicon scribing are described to demonstrate the processing benefits of the Quasar's available power, PRF, and TimeShift technology.

Pulsed Radiofrequency of Dorsal Root Ganglia for the Treatment of Complex Regional Pain Syndrome in an Adolescent with Poliomyelitis Sequel: A Case Report.

PubMed

Apiliogullari, Seza; Aydin, Bahattin Kerem; Onal, Ozkan; Kirac, Yunus; Celik, Jale Bengi

2015-07-01

Complex regional pain syndrome (CRPS) is a painful and disabling syndrome in which the patient presents with neuropathic pain, edema, or vasomotor or pseudomotor abnormalities that are often refractory to treatment. Polio paralysis is caused by the damage or destruction of motor neurons in the spine, which lead to corresponding muscle paralysis. This report is a case report on the application of a pulsed radiofrequency (PRF) current to dorsal root ganglia (DRG) for the treatment of CRPS type 1 in an adolescent patient. Single case report. Selcuk University Hospital. A 16-year-old girl who suffered from CRPS type 1 secondary to surgeries for the sequelae of poliomyelitis. PRF current application to the lumbar 4 and lumbar 5 DRG. Pain reduction. The patient had complete resolution of her symptoms, which was maintained at a 6-month follow-up. This case illustrates that PRF applied to lumbar 4 and lumbar 5 DRG may play a significant role in CRPS type 1 management after the surgical treatment of poliomyelitis sequelae in adolescent patients. Further randomized, controlled studies are needed to support this argument. Wiley Periodicals, Inc.

Concentrated Growth Factor Enhanced Fat Graft Survival: A Comparative Study.

PubMed

Hu, Yun; Jiang, Yichen; Wang, Muyao; Tian, Weidong; Wang, Hang

2018-06-08

Concentrated growth factors (CGFs) belong to a new generation biomaterials that concentrate large number of growth factors and CD34 stem cells in small volume of plasma. The purpose of this study was to evaluate the impact of the new technique, CGF, on fat graft survival, which compared with platelet-rich plasma (PRP) and platelet-rich fibrin (PRF). Nude mice received fat graft were divided into PRP group, PRF group, CGF group, and saline. The grafts were volumetrically and histologically evaluated at 4, 8, and 12 weeks after fat grafting. In vitro growth factor levels in PRP, PRF, and CGF were compared using enzyme-linked immunoassay method. Cell count and real-time polymerase chain reaction were used to evaluate the impact of CGF in medium on human adipose-derived stem cell (hADSC) proliferation and vascular differentiation, respectively. Fat graft weight was significantly higher in the CGF group than those in the other groups, and histologic evaluation revealed greater vascularity, fewer cysts, and less fibrosis. Adding CGF to the medium maximally promoted hADSC proliferation and expressing vascular endothelial growth factor and PECAM-1. In this preliminary study, CGF treatment improved the survival and quality of fat grafts.

Characterization of Ribosomal Frameshifting in Theiler's Murine Encephalomyelitis Virus.

PubMed

Finch, Leanne K; Ling, Roger; Napthine, Sawsan; Olspert, Allan; Michiels, Thomas; Lardinois, Cécile; Bell, Susanne; Loughran, Gary; Brierley, Ian; Firth, Andew E

2015-08-01

Theiler's murine encephalomyelitis virus (TMEV) is a member of the genus Cardiovirus in the Picornaviridae, a family of positive-sense single-stranded RNA viruses. Previously, we demonstrated that in the related cardiovirus, Encephalomyocarditis virus, a programmed-1 ribosomal frameshift (1 PRF) occurs at a conserved G_GUU_UUU sequence within the 2B-encoding region of the polyprotein open reading frame (ORF). Here we show that-1 PRF occurs at a similar site during translation of the TMEV genome. In addition, we demonstrate that a predicted 3= RNA stem-loop structure at a noncanonical spacing downstream of the shift site is required for efficient frameshifting in TMEV and that frameshifting also requires virus infection. Mutating the G_GUU_UUU shift site to inhibit frameshifting results in an attenuated virus with reduced growth kinetics and a small-plaque phenotype. Frameshifting in the virus context was found to be extremely efficient at 74 to 82%, which, to our knowledge, is the highest frameshifting efficiency recorded to date for any virus. We propose that highly efficient-1 PRF in TMEV provides a mechanism to escape the confines of equimolar expression normally inherent in the single-polyprotein expression strategy of picornaviruses.

High PRF ultrafast sliding compound doppler imaging: fully qualitative and quantitative analysis of blood flow

NASA Astrophysics Data System (ADS)

Kang, Jinbum; Jang, Won Seuk; Yoo, Yangmo

2018-02-01

Ultrafast compound Doppler imaging based on plane-wave excitation (UCDI) can be used to evaluate cardiovascular diseases using high frame rates. In particular, it provides a fully quantifiable flow analysis over a large region of interest with high spatio-temporal resolution. However, the pulse-repetition frequency (PRF) in the UCDI method is limited for high-velocity flow imaging since it has a tradeoff between the number of plane-wave angles (N) and acquisition time. In this paper, we present high PRF ultrafast sliding compound Doppler imaging method (HUSDI) to improve quantitative flow analysis. With the HUSDI method, full scanline images (i.e. each tilted plane wave data) in a Doppler frame buffer are consecutively summed using a sliding window to create high-quality ensemble data so that there is no reduction in frame rate and flow sensitivity. In addition, by updating a new compounding set with a certain time difference (i.e. sliding window step size or L), the HUSDI method allows various Doppler PRFs with the same acquisition data to enable a fully qualitative, retrospective flow assessment. To evaluate the performance of the proposed HUSDI method, simulation, in vitro and in vivo studies were conducted under diverse flow circumstances. In the simulation and in vitro studies, the HUSDI method showed improved hemodynamic representations without reducing either temporal resolution or sensitivity compared to the UCDI method. For the quantitative analysis, the root mean squared velocity error (RMSVE) was measured using 9 angles (-12° to 12°) with L of 1-9, and the results were found to be comparable to those of the UCDI method (L  =  N  =  9), i.e.  ⩽0.24 cm s-1, for all L values. For the in vivo study, the flow data acquired from a full cardiac cycle of the femoral vessels of a healthy volunteer were analyzed using a PW spectrogram, and arterial and venous flows were successfully assessed with high Doppler PRF (e.g. 5 kHz at L  =  4). These results indicate that the proposed HUSDI method can improve flow visualization and quantification with a higher frame rate, PRF and flow sensitivity in cardiovascular imaging.

High PRF ultrafast sliding compound doppler imaging: fully qualitative and quantitative analysis of blood flow.

PubMed

Kang, Jinbum; Jang, Won Seuk; Yoo, Yangmo

2018-02-09

Ultrafast compound Doppler imaging based on plane-wave excitation (UCDI) can be used to evaluate cardiovascular diseases using high frame rates. In particular, it provides a fully quantifiable flow analysis over a large region of interest with high spatio-temporal resolution. However, the pulse-repetition frequency (PRF) in the UCDI method is limited for high-velocity flow imaging since it has a tradeoff between the number of plane-wave angles (N) and acquisition time. In this paper, we present high PRF ultrafast sliding compound Doppler imaging method (HUSDI) to improve quantitative flow analysis. With the HUSDI method, full scanline images (i.e. each tilted plane wave data) in a Doppler frame buffer are consecutively summed using a sliding window to create high-quality ensemble data so that there is no reduction in frame rate and flow sensitivity. In addition, by updating a new compounding set with a certain time difference (i.e. sliding window step size or L), the HUSDI method allows various Doppler PRFs with the same acquisition data to enable a fully qualitative, retrospective flow assessment. To evaluate the performance of the proposed HUSDI method, simulation, in vitro and in vivo studies were conducted under diverse flow circumstances. In the simulation and in vitro studies, the HUSDI method showed improved hemodynamic representations without reducing either temporal resolution or sensitivity compared to the UCDI method. For the quantitative analysis, the root mean squared velocity error (RMSVE) was measured using 9 angles (-12° to 12°) with L of 1-9, and the results were found to be comparable to those of the UCDI method (L  =  N  =  9), i.e.  ⩽0.24 cm s -1 , for all L values. For the in vivo study, the flow data acquired from a full cardiac cycle of the femoral vessels of a healthy volunteer were analyzed using a PW spectrogram, and arterial and venous flows were successfully assessed with high Doppler PRF (e.g. 5 kHz at L  =  4). These results indicate that the proposed HUSDI method can improve flow visualization and quantification with a higher frame rate, PRF and flow sensitivity in cardiovascular imaging.

The Expression and Prognostic Impact of Immune Cytolytic Activity-Related Markers in Human Malignancies: A Comprehensive Meta-analysis.

PubMed

Roufas, Constantinos; Chasiotis, Dimitrios; Makris, Anestis; Efstathiades, Christodoulos; Dimopoulos, Christos; Zaravinos, Apostolos

2018-01-01

Recently, immune-checkpoint blockade has shown striking clinical results in different cancer patients. However, a significant inter-individual and inter-tumor variability exists among different cancers. The expression of the toxins granzyme A (GZMA) and perforin 1 (PRF1), secreted by effector cytotoxic T cells and natural killer (NK) cells, were recently used as a denominator of the intratumoral immune cytolytic activity (CYT). These levels are significantly elevated upon CD8+ T-cell activation as well as during a productive clinical response against immune-checkpoint blockade therapies. Still, it is not completely understood how different tumors induce and adapt to immune responses. Here, we calculated the CYT across different cancer types and focused on differences between primary and metastatic tumors. Using data from 10,355, primary tumor resection samples and 2,787 normal samples that we extracted from The Cancer Genome Atlas and Genotype-Tissue Expression project databases, we screened the variation of CYT across 32 different cancer types and 28 different normal tissue types. We correlated the cytolytic levels in each cancer type with the corresponding patient group's overall survival, the expression of several immune-checkpoint molecules, as well as with the load of tumor-infiltrating lymphocytes (TILs), and tumor-associated neutrophils (TANs) in these tumors. We found diverse levels of CYT across different cancer types, with highest levels in kidney, lung, and cervical cancers, and lowest levels in glioma, adrenocortical carcinoma (ACC), and uveal melanoma. GZMA protein was either lowly expressed or absent in at least half of these tumors; whereas PRF1 protein was not detected in almost any of the different tumor types, analyzing tissue microarrays from 20 different tumor types. CYT was significantly higher in metastatic skin melanoma and correlated significantly to the TIL load. In TCGA-ACC, skin melanoma, and bladder cancer, CYT was associated with an improved patient outcome and high levels of both GZMA and PRF1 synergistically affected patient survival in these cancers. In bladder, breast, colon, esophageal, kidney, ovarian, pancreatic, testicular, and thyroid cancers, high CYT was accompanied by upregulation of at least one immune-checkpoint molecule, indicating that similar to melanoma and prostate cancer, immune responses in cytolytic-high tumors elicit immune suppression in the tumor microenvironment. Overall, our data highlight the existence of diverse levels of CYT across different cancer types and suggest that along with the existence of complicated associations among various tumor-infiltrated immune cells, it is capable to promote or inhibit the establishment of a permissive tumor microenvironment, depending on the cancer type. High levels of immunosuppression seem to exist in several tumor types.

Relationship between loss of echogenicity and cavitation emissions from echogenic liposomes insonified by spectral Doppler ultrasound

NASA Astrophysics Data System (ADS)

Radhakrishnan, Kirthi

Cardiovascular disease is the leading cause of death and disability in the United States and worldwide. Echogenic liposomes (ELIP) are theragonistic ultrasound contrast agents (UCAs) being developed for the early detection and treatment of cardiovascular disease. Stability of the echogenicity of ELIP in physiologic conditions is crucial to their successful translation to clinical use. The stability of ELIP echogenicity was determined in vitro under physiologic conditions of total dissolved gas concentration, temperature, and hydrodynamic pressure in porcine plasma and whole blood. Ultrasound contrast agents (UCAs) have the potential to nucleate cavitation and promote both beneficial and deleterious bioeffects in vivo. Previous studies have elucidated the pressure amplitude threshold for rapid loss of echogenicity due to UCA fragmentation as a function of pulse duration and pulse repetition frequency (PRF). Previous studies have also demonstrated that UCA fragmentation was concomitant with inertial cavitation. The purpose of this study was to evaluate the relationship between stable and inertial cavitation thresholds and loss of echogenicity of ELIP as a function of pulse duration and pulse repetition frequency. Determining the relationship between cavitation thresholds and loss of echogenicity of ELIP would enable monitoring of cavitation based upon the on-screen echogenicity in clinical applications. ELIP were insonified by a clinical ultrasound scanner in duplex spectral Doppler mode at four pulse durations and four PRFs in a static fluid and in a flow system. Cavitation emissions from the UCAs insonified by Doppler pulses were recorded using a single-element passive cavitation detection (PCD) system and a passive cavitation imaging (PCI) system. Stable and inertial cavitation thresholds were ascertained. Loss of echogenicity from ELIP was assessed within regions of interest on B-mode images. Stable cavitation thresholds were found to be lower than inertial cavitation thresholds. Stable and inertial cavitation thresholds of ELIP were found to have a weak dependence on pulse duration. However, the stable cavitation threshold of ELIP had no dependence on PRF. The inertial cavitation threshold of ELIP had a weak dependence on PRF. Cavitation thresholds ascertained using a PCI agreed with the thresholds ascertained using a single-element PCD. The azimuthal beamwidth of the cavitation emissions detected by the PCI system agreed with the calibrated beamwidth of the insonation Doppler pressure exceeding the cavitation threshold. The power of cavitation emissions was an exponential function of the loss of echogenicity over the investigated range of acoustic pressures. ELIP lost more than 80% echogenicity before the onset of stable or inertial cavitation. Once this level of echogenicity loss occurred, both stable and inertial cavitation emissions were detected in the physiologic flow phantom. These results indicate that 80% loss of echogenicity may be used as a qualitative metric to gauge the onset of stable and inertial cavitation from ELIP.

Doppler centroid estimation ambiguity for synthetic aperture radars

NASA Technical Reports Server (NTRS)

Chang, C. Y.; Curlander, J. C.

1989-01-01

A technique for estimation of the Doppler centroid of an SAR in the presence of large uncertainty in antenna boresight pointing is described. Also investigated is the image degradation resulting from data processing that uses an ambiguous centroid. Two approaches for resolving ambiguities in Doppler centroid estimation (DCE) are presented: the range cross-correlation technique and the multiple-PRF (pulse repetition frequency) technique. Because other design factors control the PRF selection for SAR, a generalized algorithm is derived for PRFs not containing a common divisor. An example using the SIR-C parameters illustrates that this algorithm is capable of resolving the C-band DCE ambiguities for antenna pointing uncertainties of about 2-3 deg.

Sensitivity Analysis of Sampling Number on Quality of Polarmetric Measurements from S-band Dual-Polarization Radar

NASA Astrophysics Data System (ADS)

KIM, H.; Suk, M. K.; Jung, S. A.; Park, J. S.; Ko, J. S.

2016-12-01

The data quality of dual-polarimetric weather radar is subject to radar scanning strategies such as pulse length, pulse repetition frequency (PRF), antenna scan speed, and sampling number. In terms of sampling number, the quality of radar moment data increases with the increasing of sampling number at the given PRF and pulse length while the feasible number of elevation angles decreases for the given time or the time required for radar volume scan increases with the relatively high sampling number. For operational weather radar, the sampling number is subjectively determined by the proficient radar operator. The determination of suitable sampling number is still challengeable for operational dual-polarimetric weather radar.In this study, we analyzed the sensitivity of polarimetric measurements to sampling number based on special radar experiment for rainfall and snowfall events using S-band dual-polarimetric radar (YIT) at Yong-In test bed. For this experiment, YIT radar transmitted a simultaneously polarized beam in horizontal and vertical with pulse length of 1.0 μs and single PRF of 600Hz. The beam width and gate size were 1.0° and 250m, respectively. The volume scan was composed of three PPI scans with three sampling numbers (antenna scan speed) of 40 (15°s-1), 60(10°s-1), and 85(7°s-1) at same elevation angle (=0.2°). We first investigated the spatial fluctuation of the polarimetric measurements according to three sampling numbers using radial texture. As the sampling number increases, the radial fluctuations of polarimetric measurements decrease. Second, we also examined the sensitivity to fuzzy logic based quality control algorithm for dual-polarimetric radar (Ye et al. 2015). The probability density functions (PDFs) of fuzzy logic feature parameters between ground clutter and meteorological echo area were compared. For overlapping area in both PDFs between ground clutter and meteorological echo increases with decreasing the sampling number. As the overlapping area increases, the classification of ground clutter (or meteorological echo) in fuzzy logic classifier is more difficult due to similar characteristics between ground clutter and meteorological echoes.

Identification, characterisation and expression analysis of natural killer receptor genes in Chlamydia pecorum infected koalas (Phascolarctos cinereus).

PubMed

Morris, Katrina M; Mathew, Marina; Waugh, Courtney; Ujvari, Beata; Timms, Peter; Polkinghorne, Adam; Belov, Katherine

2015-10-15

Koalas (Phascolarctos cinereus), an iconic Australian marsupial, are being heavily impacted by the spread of Chlamydia pecorum, an obligate intracellular bacterial pathogen. Koalas vary in their response to this pathogen, with some showing no symptoms, while others suffer severe symptoms leading to infertility, blindness or death. Little is known about the pathology of this disease and the immune response against it in this host. Studies have demonstrated that natural killer (NK) cells, key components of the innate immune system, are involved in the immune response to chlamydial infections in humans. These cells can directly lyse cells infected by intracellular pathogens and their ability to recognise these infected cells is mediated through NK receptors on their surface. These are encoded in two regions of the genome, the leukocyte receptor complex (LRC) and the natural killer complex (NKC). These two families evolve rapidly and different repertoires of genes, which have evolved by gene duplication, are seen in different species. In this study we aimed to characterise genes belonging to the NK receptor clusters in the koala by searching available koala transcriptomes using a combination of search methods. We developed a qPCR assay to quantify relative expression of four genes, two encoded within the NK receptor cluster (CLEC1B, CLEC4E) and two known to play a role in NK response to Chalmydia in humans (NCR3, PRF1). We found that the NK receptor repertoire of the koala closely resembles that of the Tasmanian devil, with minimal genes in the NKC, but with lineage specific expansions in the LRC. Additional genes important for NK cell activity, NCR3 and PRF1, were also identified and characterised. In a preliminary study to investigate whether these genes are involved in the koala immune response to infection by its chlamydial pathogen, C. pecorum, we investigated the expression of four genes in koalas with active chlamydia infection, those with past infection and those without infection using qPCR. This analysis revealed that one of these four, CLEC4E, may be upregulated in response to chlamydia infection. We have characterised genes of the NKC and LRC in koalas and have discovered evidence that one of these genes may be upregulated in koalas with chlamydia, suggesting that these receptors may play a role in the immune response of koalas to chlamydia infection.

Platelet-Released Growth Factors Induce Differentiation of Primary Keratinocytes

PubMed Central

Tohidnezhad, Mersedeh; Lammel, Justus; Lippross, Sebastian; Behrendt, Peter; Klüter, Tim; Pufe, Thomas; Jahr, Holger; Cremer, Jochen; Rademacher, Franziska; Gläser, Regine; Harder, Jürgen

2017-01-01

Autologous thrombocyte concentrate lysates, for example, platelet-released growth factors, (PRGFs) or their clinically related formulations (e.g., Vivostat PRF®) came recently into the physicians' focus as they revealed promising effects in regenerative and reparative medicine such as the support of healing of chronic wounds. To elucidate the underlying mechanisms, we analyzed the influence of PRGF and Vivostat PRF on human keratinocyte differentiation in vitro and on epidermal differentiation status of skin wounds in vivo. Therefore, we investigated the expression of early (keratin 1 and keratin 10) and late (transglutaminase-1 and involucrin) differentiation markers. PRGF treatment of primary human keratinocytes decreased keratin 1 and keratin 10 gene expression but induced involucrin and transglutaminase-1 gene expression in an epidermal growth factor receptor- (EGFR-) dependent manner. In concordance with these results, microscopic analyses revealed that PRGF-treated human keratinocytes displayed morphological features typical of keratinocytes undergoing terminal differentiation. In vivo treatment of artificial human wounds with Vivostat PRF revealed a significant induction of involucrin and transglutaminase-1 gene expression. Together, our results indicate that PRGF and Vivostat PRF induce terminal differentiation of primary human keratinocytes. This potential mechanism may contribute to the observed beneficial effects in the treatment of hard-to-heal wounds with autologous thrombocyte concentrate lysates in vivo. PMID:28808357

Alleviating artifacts in 1H MRI thermometry by single scan spatiotemporal encoding.

PubMed

Schmidt, Rita; Frydman, Lucio

2013-10-01

Recent years have seen an increased interest in combining MRI thermometry with devices capable of destroying malignancies by heat ablation. Expected from the MR protocols are accurate and fast thermal characterizations, providing real time feedback on restricted tissue volumes and/or rapidly moving organs like liver. This article explores the potential advantages of relying on spatiotemporally encoded (SPEN) sequences for retrieving real-time thermometric images based on the water's proton resonance frequency (PRF) shifts. Hybrid spatiotemporal/k-space encoding single-scan MRI experiments were implemented on animal and human scanners, and their abilities to deliver single- and multi-slice real-time thermometric measurements based on PRF-derived phase maps in phantoms and in vivo, were compared against echo planar imaging (EPI) and gradient-echo counterparts. Under comparable acquisition conditions, SPEN exhibited advantages vis-à-vis EPI in terms of dealing with inhomogeneous magnetic field distortions, with shifts arising due to changes in the central frequency offsets, with PRF distributions, and for zooming into restricted fields-of-view without special pulse sequence provisions. This work confirms the ability of SPEN sequences, particularly when implemented under fully-refocused conditions, to exploit their built-in robustness to shift- and field-derived inhomogeneities for monitoring thermal changes in real-time under in vitro and in vivo conditions.

A new technique to treat facet joint pain with pulsed radiofrequency.

PubMed

Schianchi, Pietro Martino

2015-02-01

Facet joint pain affects 5% to 15% of the population with low back pain and the prevalence increases with age due to progression of arthritis. While conservative treatments are often unsuccessful, the scientific evidence on minimally invasive therapies such as intra-articular steroid infiltration and continuous and pulsed radiofrequency (PRF) of the medial branches is contradictory. Since PRF has recently been reported to successfully treat joint pain, a new application of this method is proposed for facetogenic lumbar pain via an intra-articular subcapsular approach. Here we reported two cases with successful treatment. A 71-year-old patient presented because of persisting pain in the left gluteal region radiating to the lateral thigh and calf when standing. Anti-inflammatory drugs produced only short-lasting insufficient relief. A 52-year-old employee was admitted in June 2012 because of axial lower lumbar pain with intermittent diffuse radiation to the right lower extremity that worsened during walking and lying down despite receiving analgesics and physiotherapy. A new approach to treat lumbar facet joint pain with PRF is simple to perform and without serious complications. In view of the good long-lasting results obtained with the two reported cases, randomized control trials are necessary to validate this new approach.

Systematic Review of Radiofrequency Ablation and Pulsed Radiofrequency for Management of Cervicogenic Headaches.

PubMed

Grandhi, Ravi K; Kaye, Alan David; Abd-Elsayed, Alaa

2018-02-23

Cervicogenic headache (CHA) is a secondary headache which has a source in the upper cervical spine. Many traditional analgesic choices lack good efficacy in managing the associated pain. As a result, in management of CHA, radiofrequency ablation (RFA) or pulse radiofrequency (PRF) has been tried with success. Our study investigated the use of RFA and PRF for the management of CHA. In the present investigation, a review of the literature was conducted using PubMed (1966 to February 2017). The quality assessment was determined using The Cochrane Risk of Bias. After initial search and consultation with experts, 34 articles were identified for initial review and 10 articles met inclusion for review. Criteria for inclusion were primarily based on identification of articles discussing cervicogenic headaches which were previously treatment resistant and occurred without any other pathology of the craniofacial region or inciting event such as trauma. This systematic review demonstrated that RFA and PRFA provide very limited benefit in the management of CHA. At present, there is no high-quality RCT and/or strong non-RCTs to support the use of these techniques, despite numerous case reports which have demonstrated benefit. This review is one of the first to provide a comprehensive overview of the use of RFA and PRF in the management of CHA.

Rheological properties and tunable thermoplasticity of phenolic rich fraction of pyrolysis bio-oil.

PubMed

Sahaf, Amir; Laborie, Marie-Pierre G; Englund, Karl; Garcia-Perez, Manuel; McDonald, Armando G

2013-04-08

In this work we report on the preparation, characterization, and properties of a thermally treated lignin-derived, phenolic-rich fraction (PRF) of wood pyrolysis bio-oil obtained by ethyl acetate extraction. The PRF was characterized for viscoelastic and rheological behavior using dynamic mechanical analysis (DMA) and cone and plate rheology. A unique thermoplastic behavior was evidenced. Heat-treated PRFs acquire high modulus but show low temperatures of thermal flow which can be systematically manipulated through the thermal pretreatment. Loss of volatiles, changes in molecular weight, and glass transition temperature (Tg) were investigated using thermogravimetric analysis (TGA), mass spectrometry (MS), and differential scanning calorimetry (DSC), respectively. Underlying mechanisms for the thermal and rheological behavior are discussed with regard to interactions between pyrolytic lignin nanoparticles present in the system and the role of volatile materials on determining the properties of the material resembling in several aspects to colloidal suspension systems. Low thermal flow temperatures and reversible thermal effects can be attributed to association of pyrolytic lignin particles due to intermolecular interactions that are easily ruptured at higher temperatures. The thermoplastic behavior of PRF and its low Tg is of particular interest, as it gives opportunities for application of this fraction in several melt processing and adhesive technologies.

A method for constructing single-copy lac fusions in Salmonella typhimurium and its application to the hemA-prfA operon.

PubMed

Elliott, T

1992-01-01

This report describes a set of Escherichia coli and Salmonella typhimurium strains that permits the reversible transfer of lac fusions between a plasmid and either bacterial chromosome. The system relies on homologous recombination in an E. coli recD host for transfer from plasmid to chromosome. This E. coli strain carries the S. typhimurium put operon inserted into trp, and the resulting fusions are of the form trp::put::[Kanr-X-lac], where X is the promoter or gene fragment under study. The put homology flanks the lac fusion segment, so that fusions can be transduced into S. typhimurium, replacing the resident put operon. Subsequent transduction into an S. typhimurium strain with a large chromosomal deletion covering put allows selection for recombinants that inherit the fusion on a plasmid. A transposable version of the put operon was constructed and used to direct lac fusions to novel locations, including the F plasmid and the ara locus. Transductional crosses between strains with fusions bearing different segments of the hemA-prfA operon were used to determine the contribution of the hemA promoter region to expression of the prfA gene and other genes downstream of hemA in S. typhimurium.

The nodC, nodG, and glgX genes of Rhizobium tropici strain PRF 81.

PubMed

Oliveira, Luciana Ruano; Marcelino, Francismar Corrêa; Barcellos, Fernando Gomes; Rodrigues, Elisete Pains; Megías, Manuel; Hungria, Mariangela

2010-08-01

Rhizobium tropici is a diazotrophic microsymbiont of common bean (Phaseolus vulgaris L.) that encompasses important but still poorly studied tropical strains, and a recent significant contribution to the knowledge of the species was the publication of a genomic draft of strain PRF 81, which revealed several novel genes [Pinto et al. Funct Int Gen 9:263-270, 2009]. In this study, we investigated the transcription of nodC, nodG, and glgX genes, located in the nod operon of PRF 81 strain, by reverse-transcription quantitative PCR. All three genes showed low levels of transcription when the cells were grown until exponential growth phase in the presence of common-bean-seed exudates or of the root nod-gene inducer naringenin. However, when cells at the exponential phase of growth were incubated with seed exudates, transcription occurred after only 5 min, and nodC, nodG, and glgX were transcribed 121.97-, 14.86-, and 50.29-fold more than the control, respectively, followed by a rapid decrease in gene transcription. Much lower levels of transcription were observed in the presence of naringenin; furthermore, maximum transcription required 8 h of incubation for all three genes. In light of these results, the mechanisms of induction of the nodulation genes by flavonoids are discussed.

Possible regulation of cation-induced pinocytosis in Amoeba proteus by phospholipase A.

PubMed

Josefsson, J O; Arvidson, G; Cobbold, P

1988-04-01

We have studied the effects of exogenous phospholipids and compounds which are known to alter the activity of phospholipase A (PLA) on Ca2+-dependent, Na+-induced pinocytosis in Amoeba proteus. The PLA-inhibitors mepacrine, p-bromophenacyl bromide (pBPB) and Rosenthal's inhibitor depressed pinocytosis. Normal pinocytotic intensity was restored by the addition of Ca2+ or picomolar concentrations of lysolecithin. Very low concentrations of lysophospholipids and different molecular species of lecithins increased the capacity for pinocytosis in starved amoebae. The effect of the lecithins but not of the corresponding lysolecithins was abolished by PLA-inhibitors. Also, the restoration of the pinocytotic capacity of starved amoebae by melittin and mastoparan, which are known to stimulate PLA, was inhibited by mepacrine and pBPB. Isolated amoeba plasma membranes contain phospholipase A1 and A2 activity and the amoebae secrete a lipid (PRF, pinocytosis regulating factor) which has lysolecithin-like effects on pinocytosis. The enzyme activities and the release of PRF were markedly decreased by the PLA-inhibitors. Our observations support the hypothesis that PRF is a lysophospholipid that may constitute a signal for the formation of pinocytotic channels in the initial stages of pinocytosis. The phospholipase A activity of the amoeba must therefore be assigned an important role in the regulation of the Ca2+-dependent, cation-induced pinocytosis.

The role of titanium-prepared platelet-rich fibrin in palatal mucosal wound healing and histoconduction.

PubMed

Ustaoğlu, Gülbahar; Ercan, Esra; Tunali, Mustafa

2016-10-01

We aimed to determine the clinical effects of titanium-prepared, platelet-rich fibrin (T-PRF) on human palatal mucosal wound healing (PMWH) and to identify its effect on time-dependent changes in palatal soft-tissue thickness (PSTT) in terms of histoconduction, which is a new concept. Free gingival graft (FGG) donor sites were treated with T-PRF and compared with an untreated control group. The results of colour match and H 2 O 2 -bubbling tests for complete wound epithelization (CWE) were recorded on days 3, 7, 14 and 21. Pain level, number of analgesics used and bleeding status were recorded for the first 7 days. PSTT was measured at baseline and after 1 and 6 months. Colour match scores of the test group were significantly higher than those of the control group at 7 and 14 days. CWE was observed at a higher frequency in the test group than in the control group on day 14. Post-operative bleeding prevalence was lower in the test group than in the control group for the first 2 days. A time-dependent decrease in PSTT was observed at 1 and 6 months in the control group compared with baseline (baseline, 4.23 ± 0.62 mm; 1 month, 4.01 ± 0.68 mm; and 6 months, 3.93 ± 0.69 mm). However, no significant difference was found in the test group (baseline, 4.29 ± 0.64 mm; 1 month, 4.61 ± 0.51 mm; and 6 months, 4.51 ± 0.58 mm). The T-PRF membrane exhibited positive effects on PMWH. T-PRF, which is a promising autogenous matrix for histoconduction, may also be preferred as an autogenous alternative to connective tissue grafts in the treatment of gingival recessions and peri-implant mucosal recessions.

Reduction of relative centrifugation force within injectable platelet-rich-fibrin (PRF) concentrates advances patients' own inflammatory cells, platelets and growth factors: the first introduction to the low speed centrifugation concept.

PubMed

Choukroun, J; Ghanaati, S

2018-02-01

The aim of this study was to analyze systematically the influence of the relative centrifugation force (RCF) on leukocytes, platelets and growth factor release within fluid platelet-rich fibrin matrices (PRF). Systematically using peripheral blood from six healthy volunteers, the RCF was reduced four times for each of the three experimental protocols (I-III) within the spectrum (710-44 g), while maintaining a constant centrifugation time. Flow cytometry was applied to determine the platelets and leukocyte number. The growth factor concentration was quantified 1 and 24 h after clotting using ELISA. Reducing RCF in accordance with protocol-II (177 g) led to a significantly higher platelets and leukocytes numbers compared to protocol-I (710 g). Protocol-III (44 g) showed a highly significant increase of leukocytes and platelets number in comparison to -I and -II. The growth factors' concentration of VEGF and TGF-β1 was significantly higher in protocol-II compared to -I, whereas protocol-III exhibited significantly higher growth factor concentration compared to protocols-I and -II. These findings were observed among 1 and 24 h after clotting, as well as the accumulated growth factor concentration over 24 h. Based on the results, it has been demonstrated that it is possible to enrich PRF-based fluid matrices with leukocytes, platelets and growth factors by means of a single alteration of the centrifugation settings within the clinical routine. We postulate that the so-called low speed centrifugation concept (LSCC) selectively enriches leukocytes, platelets and growth factors within fluid PRF-based matrices. Further studies are needed to evaluate the effect of cell and growth factor enrichment on wound healing and tissue regeneration while comparing blood concentrates gained by high and low RCF.

Pain Research Forum: application of scientific social media frameworks in neuroscience.

PubMed

Das, Sudeshna; McCaffrey, Patricia G; Talkington, Megan W T; Andrews, Neil A; Corlosquet, Stéphane; Ivinson, Adrian J; Clark, Tim

2014-01-01

Social media has the potential to accelerate the pace of biomedical research through online collaboration, discussions, and faster sharing of information. Focused web-based scientific social collaboratories such as the Alzheimer Research Forum have been successful in engaging scientists in open discussions of the latest research and identifying gaps in knowledge. However, until recently, tools to rapidly create such communities and provide high-bandwidth information exchange between collaboratories in related fields did not exist. We have addressed this need by constructing a reusable framework to build online biomedical communities, based on Drupal, an open-source content management system. The framework incorporates elements of Semantic Web technology combined with social media. Here we present, as an exemplar of a web community built on our framework, the Pain Research Forum (PRF) (http://painresearchforum.org). PRF is a community of chronic pain researchers, established with the goal of fostering collaboration and communication among pain researchers. Launched in 2011, PRF has over 1300 registered members with permission to submit content. It currently hosts over 150 topical news articles on research; more than 30 active or archived forum discussions and journal club features; a webinar series; an editor-curated weekly updated listing of relevant papers; and several other resources for the pain research community. All content is licensed for reuse under a Creative Commons license; the software is freely available. The framework was reused to develop other sites, notably the Multiple Sclerosis Discovery Forum (http://msdiscovery.org) and StemBook (http://stembook.org). Web-based collaboratories are a crucial integrative tool supporting rapid information transmission and translation in several important research areas. In this article, we discuss the success factors, lessons learned, and ongoing challenges in using PRF as a driving force to develop tools for online collaboration in neuroscience. We also indicate ways these tools can be applied to other areas and uses.

Reduction in the mRNA expression of sVEGFR1 and sVEGFR2 is associated with the selection of dominant follicle in cows.

PubMed

Ortega Serrano, P V; Guzmán, A; Hernández-Coronado, C G; Castillo-Juárez, H; Rosales-Torres, A M

2016-12-01

The vascular endothelial growth factor (VEGF) is essential for follicular development by promoting follicular angiogenesis, as well as for the proliferation and survival of granulosa cells. The biological effects of VEGF are regulated by two membrane receptors, VEGFR1 and VEGFR2, and two soluble receptors, sVEGFR1 and sVEGFR2, which play an antagonistic role. Thus, the objective of this study was to identify the mRNA expression pattern of total VEGF, VEGFR1, VEGFR2, sVEGFR1 and sVEGFR2 in bovine preselected follicles (PRF) and post-selected follicles (POF). The mRNA expression of these five genes in both granulosa cells (GC) and theca cells (TC) was compared between follicles classified as PRF and POF based on their diameter and on their ratio of estradiol/progesterone (E2/P4). Results showed a lower expression of mRNA of sVEGFR1 and sVEGFR2 in POF than in PRF (p < .05). Regarding the mRNA expression of total VEGF, VEGFR1 and VEGFR2, there was no difference between POF and PRF follicles (p > .05). Our results showed that the mRNA expression of VEGFR2 and sVEGFR1 was more abundant than the expression of VEGFR1 and sVEGFR2, while GC was the main source of mRNA for total VEGF. On the other hand, TC was the follicular compartment where the receptors were most expressed. Our results suggest that non-dominant follicles maintain a greater concentration of the mRNA expression of both membrane and soluble VEGF receptors. On the other hand, follicular dominance is related to a reduction in the mRNA expression of sVEGFR1 and sVEGFR2, which may favour VEGF binding with VEGFR2 and, hence, improve the follicular health and development. © 2016 Blackwell Verlag GmbH.

Pain Research Forum: application of scientific social media frameworks in neuroscience

PubMed Central

Das, Sudeshna; McCaffrey, Patricia G.; Talkington, Megan W. T.; Andrews, Neil A.; Corlosquet, Stéphane; Ivinson, Adrian J.; Clark, Tim

2014-01-01

Background: Social media has the potential to accelerate the pace of biomedical research through online collaboration, discussions, and faster sharing of information. Focused web-based scientific social collaboratories such as the Alzheimer Research Forum have been successful in engaging scientists in open discussions of the latest research and identifying gaps in knowledge. However, until recently, tools to rapidly create such communities and provide high-bandwidth information exchange between collaboratories in related fields did not exist. Methods: We have addressed this need by constructing a reusable framework to build online biomedical communities, based on Drupal, an open-source content management system. The framework incorporates elements of Semantic Web technology combined with social media. Here we present, as an exemplar of a web community built on our framework, the Pain Research Forum (PRF) (http://painresearchforum.org). PRF is a community of chronic pain researchers, established with the goal of fostering collaboration and communication among pain researchers. Results: Launched in 2011, PRF has over 1300 registered members with permission to submit content. It currently hosts over 150 topical news articles on research; more than 30 active or archived forum discussions and journal club features; a webinar series; an editor-curated weekly updated listing of relevant papers; and several other resources for the pain research community. All content is licensed for reuse under a Creative Commons license; the software is freely available. The framework was reused to develop other sites, notably the Multiple Sclerosis Discovery Forum (http://msdiscovery.org) and StemBook (http://stembook.org). Discussion: Web-based collaboratories are a crucial integrative tool supporting rapid information transmission and translation in several important research areas. In this article, we discuss the success factors, lessons learned, and ongoing challenges in using PRF as a driving force to develop tools for online collaboration in neuroscience. We also indicate ways these tools can be applied to other areas and uses. PMID:24653693

On the effect of injection timing on the ignition of lean PRF/air/EGR mixtures under direct dual fuel stratification conditions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Luong, Minh Bau; Sankaran, Ramanan; Yu, Gwang Hyeon

2017-06-09

The ignition characteristics of lean primary reference fuel (PRF)/air/exhaust gas recirculation (EGR) mixture under reactivity-controlled compression ignition (RCCI) and direct duel fuel stratification (DDFS) conditions are investigated in this paper by 2-D direct numerical simulations (DNSs) with a 116-species reduced chemistry of the PRF oxidation. The 2-D DNSs of the DDFS combustion are performed by varying the injection timing of iso-octane (i-C 8H 18) with a pseudo-iso-octane (PC 8H 18) model together with a novel compression heating model to account for the compression heating and expansion cooling effects of the piston motion in an engine cylinder. The PC 8H 18more » model is newly developed to mimic the timing, duration, and cooling effects of the direct injection of i-C 8H 18 onto a premixed background charge of PRF/air/EGR mixture with composition inhomogeneities. It is found that the RCCI combustion exhibits a very high peak heat release rate (HRR) with a short combustion duration due to the predominance of the spontaneous ignition mode of combustion. However, the DDFS combustion has much lower peak HRR and longer combustion duration regardless of the fuel injection timing compared to those of the RCCI combustion, which is primarily attributed to the sequential injection of i-C 8H 18. It is also found that the ignition delay of the DDFS combustion features a non-monotonic behavior with increasing fuel-injection timing due to the different effect of fuel evaporation on the low-, intermediate-, and high-temperature chemistry of the PRF oxidation. The budget and Damköhler number analyses verify that although a mixed combustion mode of deflagration and spontaneous ignition exists during the early phase of the DDFS combustion, the spontaneous ignition becomes predominant during the main combustion, and hence, the spread-out of heat release rate in the DDFS combustion is mainly governed by the direct injection process of i-C 8H 18. Finally, a misfire is observed for the DDFS combustion when the direct injection of i-C 8H 18 occurs during the intermediate-temperature chemistry (ITC) regime between the first- and second-stage ignition. Finally, this is because the temperature drop induced by the direct injection of i-C 8H 18 impedes the main ITC reactions, and hence, the main combustion fails to occur.« less

Whole-Exome Sequencing Reveals Mutations in Genes Linked to Hemophagocytic Lymphohistiocytosis and Macrophage Activation Syndrome in Fatal Cases of H1N1 Influenza.

PubMed

Schulert, Grant S; Zhang, Mingce; Fall, Ndate; Husami, Ammar; Kissell, Diane; Hanosh, Andrew; Zhang, Kejian; Davis, Kristina; Jentzen, Jeffrey M; Napolitano, Lena; Siddiqui, Javed; Smith, Lauren B; Harms, Paul W; Grom, Alexei A; Cron, Randy Q

2016-04-01

Severe H1N1 influenza can be lethal in otherwise healthy individuals and can have features of reactive hemophagocytic lymphohistiocytosis (HLH). HLH is associated with mutations in lymphocyte cytolytic pathway genes, which have not been previously explored in H1N1 influenza. Sixteen cases of fatal influenza A(H1N1) infection, 81% with histopathologic hemophagocytosis, were identified and analyzed for clinical and laboratory features of HLH, using modified HLH-2004 and macrophage activation syndrome (MAS) criteria. Fourteen specimens were subject to whole-exome sequencing. Sequence alignment and variant filtering detected HLH gene mutations and potential disease-causing variants. Cytolytic function of the PRF1 p.A91V mutation was tested in lentiviral-transduced NK-92 natural killer (NK) cells. Despite several lacking variables, cases of influenza A(H1N1) infection met 44% and 81% of modified HLH-2004 and MAS criteria, respectively. Five subjects (36%) carried one of 3 heterozygous LYST mutations, 2 of whom also possessed the p.A91V PRF1 mutation, which was shown to decrease NK cell cytolytic function. Several patients also carried rare variants in other genes previously observed in MAS. This cohort of fatal influenza A(H1N1) infections confirms the presence of hemophagocytosis and HLH pathology. Moreover, the high percentage of HLH gene mutations suggests they are risk factors for mortality among individuals with influenza A(H1N1) infection. © The Author 2015. Published by Oxford University Press for the Infectious Diseases Society of America. All rights reserved. For permissions, e-mail journals.permissions@oup.com.

Noise Source Identification and Dynamic Modeling of a Pneumatic Nailing Device =

NASA Astrophysics Data System (ADS)

Nili Ahmadabadi, Zahra

Exposure to hazardous noise levels emitted by pneumatic nailing devices contributes significantly to risk of hearing damage among the construction workers throughout the world. This health problem comes from the lack of appropriate technology such as low noise devices which in turn results from the lack of scientific knowledge about designing reduced noise devices. This study contributes to the design improvement of pneumatic nailing devices through identifying the noise sources and developing the simulation tool required to redesign the pneumatic nailing device. To identify the noise sources, the study uses a combination of two complementary experimental approaches. The first makes use of time-synchronized data analysis of several variables during the machine operation. This strategy allows identifying the physical processes and provides a detailed separation of the noise generation mechanisms in successive time sequences. However, since multiple noise sources radiate at the same time, this observation approach is not sufficient for noise source identification and ranking. Thus, it is completed by a selective wrapping and muffler procedure. This technique provides overall generated noise associated with each process, as well as ranking of the three major sources: (1) exhaust noise, (2) machine body vibrations, and (3) workpiece vibrations. A special investigation is conducted on this third one with two cases: a workpiece/worktable setup representative of the actual field usage of a nailing device and a workpiece/sandbox setup used in a standardized laboratory test. The study evaluates the efficiency of the workpiece/sandbox setup in reducing the workpiece radiation and obtains a typical workpiece contribution on an actual worksite. To provide a simulation tool, a dynamic model of the pneumatic nailing device needs to be developed. Dynamic modeling of the nailing device requires mathematical modeling of the physical processes involved in its operation. All of these processes can be described through already existing mathematical relations, except for the penetration resistance force (PRF) imposed on the nails when penetrating the wood. The PRF depends on various factors. This study follows two approaches in parallel to develop an empirical prediction law for the PRF: quasi-static and high-speed. The quasi-static approach provides a rapid and precise representation of the law at quasistatic penetration velocities. The law covers the entire displacement range, various nail geometries and sizes, and wood types. The high-speed approach aims to provide a law which covers a much wider range of penetration velocities. The approach is complicated since it requires a sophisticated test machine to conduct the nail driving tests at high penetration velocities. The study designs and fabricates an advanced test machine to later extend the prediction range of the PRF law. The last part of this study develops the dynamic model of a nail gun while integrating the quasi-static PRF law. The model includes dynamics of all the air chambers and the moving parts, and interactions and impacts/contacts between different parts. The study integrates a comprehensive experimental validation of the model. Future improvements in the dynamic model precision will be possible by using the extended version of the PRF law.

Platelet-rich-fibrin: A novel root coverage approach

PubMed Central

Anilkumar, K.; Geetha, A.; Umasudhakar; Ramakrishnan, T; Vijayalakshmi, R; Pameela, E.

2009-01-01

Treatment of gingival recession has become an important therapeutic issue due to increasing cosmetic demand. Multiple surgical procedures have been developed to obtain predictable esthetic root coverage. More specifically, after periodontal regenerative surgery, the aim is to achieve complete wound healing and regeneration of the periodontal unit. A recent innovation in dentistry is the preparation and use of platelet-rich plasma (PRP), a concentrated suspension of the growth factors, found in platelets. These growth factors are involved in wound healing and postulated as promoters of tissue regeneration. This paper reports the use of PRF membrane for root coverage on the labial surfaces of the mandibular anterior teeth. This was accomplished using laterally displaced flap technique with platelet rich fibrin (PRF) membrane at the recipient site. PMID:20376243

Pricing end-of-life components

NASA Astrophysics Data System (ADS)

Vadde, Srikanth; Kamarthi, Sagar V.; Gupta, Surendra M.

2005-11-01

The main objective of a product recovery facility (PRF) is to disassemble end-of-life (EOL) products and sell the reclaimed components for reuse and recovered materials in second-hand markets. Variability in the inflow of EOL products and fluctuation in demand for reusable components contribute to the volatility in inventory levels. To stay profitable the PRFs ought to manage their inventory by regulating the price appropriately to minimize holding costs. This work presents two deterministic pricing models for a PRF bounded by environmental regulations. In the first model, the demand is price dependent and in the second, the demand is both price and time dependent. The models are valid for single component with no inventory replenishment sale during the selling horizon . Numerical examples are presented to illustrate the models.

Broadly wavelength tunable acousto-optically Q-switched Tm:Lu2SiO5 laser.

PubMed

Feng, T; Yang, K; Zhao, S; Zhao, J; Qiao, W; Li, T; Zheng, L; Xu, J

2014-09-20

A broadly wavelength tunable acousto-optically Q-switched Tm:Lu2SiO5 (Tm:LSO) laser is presented for the first time, to our best knowledge. The emission wavelength was tuned in a broad spectral region over 111 nm ranging from 1959 to 2070 nm. A shortest pulse duration of 345 ns with beam quality of M(2)≤1.65 was obtained at pulse repetition frequency (PRF) of 1 kHz, corresponding to a maximum single pulse energy of 0.26 mJ and peak power of 0.75 kW. The experimental results indicated that Tm:LSO crystal has outstanding potential for obtaining broadly wavelength tunable and low-PRF laser pulses at 2 μm.

Lysolecithin as a modifier of induced pinocytosis in Amoeba proteus.

PubMed

Arvidson, G; Josefsson, J O

1982-08-01

Lysolecithin was found to modify cation-induced pinocytosis in Amoeba proteus. It is shown here that lysolecithin (LPC) in the concentration range of 10(-15) to 10(-10) g/ml has the same effect on Na+ -induced pinocytosis as cAMP and a pinocytosis regulating factor (PRF) which is secreted by the amoeba. Thus, LPC activated Na+-induced pinocytosis in starved amoebae and decreased the sensitivity to the inducer in normal cells. Pinocytosis depressed by treatment with EGTA or dibucaine became normal upon addition of LPC to the inducer. These effects were also obtained with lysolecithin isolated from the amoeba. It is suggested that PRF and amoeba LPC may be closely related and that phospholipase activity of the amoeba may regulate its capacity for pinocytosis.

Comparative clinical evaluation of coronally advanced flap with or without platelet rich fibrin membrane in the treatment of isolated gingival recession

PubMed Central

Thamaraiselvan, Murugan; Elavarasu, Sugumari; Thangakumaran, Suthanthiran; Gadagi, Jayaprakash Sharanabasappa; Arthie, Thangavelu

2015-01-01

Aim: The aim of this study was to determine whether the addition of an autologous platelet rich fibrin (PRF) membrane to a coronally advanced flap (CAF) would improve the clinical outcome in terms of root coverage, in the treatment of isolated gingival recession. Materials and Methods: Systemically healthy 20 subjects each with single Miller's class I or II buccal recession defect were randomly assigned to control (CAF) or test (CAF + PRF) group. Clinical outcome was determined by measuring the following clinical parameters such as recession depth (RD), recession width (RW), probing depth (PD), clinical attachment level (CAL), width of keratinized tissue (WKT), gingival thickness (GTH), plaque index (PI), and gingival index (GI) at baseline, 3rd, and 6th month postsurgery. Results: The root coverage was 65.00 ± 44.47% in the control group and 74.16 ± 28.98% in the test group at 6th month, with no statistically significant difference between them. Similarly, CAL, PD, and WKT between the groups were not statistically significant. Conversely, there was statistically significant increase in GTH in the test group. Conclusion: CAF is a predictable treatment for isolated Miller's class I and II recession defects. The addition of PRF to CAF provided no added advantage in terms of root coverage except for an increase in GTH. PMID:25810596

Influence of Leukocyte- and Platelet-Rich Fibrin (L-PRF) in the Healing of Simple Postextraction Sockets: A Split-Mouth Study.

PubMed

Marenzi, Gaetano; Riccitiello, Francesco; Tia, Mariano; di Lauro, Alessandro; Sammartino, Gilberto

2015-01-01

The aim of this study was to evaluate the effects of leukocyte- and platelet-rich fibrin (L-PRF) on the pain and soft tissue healing after tooth extractions. Twenty-six patients (9 males and 17 females) were treated with multiple extractions (2 to 8), with a total of 108 extractions. This was an exploratory single blinded randomized clinical trial with a split-mouth design. The pain after the surgery was assessed in each patient by the VAS scale (1 to 10) at intervals of 24-48-72-96 hours. The soft tissue healing was clinically evaluated at 3, 7, 14, and 21 days after surgery by the same examiner surgeon, using the modified Healing Index (4 to 12). The mean value of postextraction pain was 3.2 ± 0.3 in the experimental sides and 4.1 ± 0.1 in the control sides. After 7 days from the extractions, the values of modified Healing Index in the experimental and control groups were, respectively, 4.8 ± 0.6 and 5.1 ± 0.9. The use of L-PRF in postextraction sockets filling can be proposed as a useful procedure in order to manage the postoperative pain and to promote the soft tissue healing process, reducing the early adverse effects of the inflammation.

Influence of Leukocyte- and Platelet-Rich Fibrin (L-PRF) in the Healing of Simple Postextraction Sockets: A Split-Mouth Study

PubMed Central

Riccitiello, Francesco; Tia, Mariano; di Lauro, Alessandro; Sammartino, Gilberto

2015-01-01

The aim of this study was to evaluate the effects of leukocyte- and platelet-rich fibrin (L-PRF) on the pain and soft tissue healing after tooth extractions. Twenty-six patients (9 males and 17 females) were treated with multiple extractions (2 to 8), with a total of 108 extractions. This was an exploratory single blinded randomized clinical trial with a split-mouth design. The pain after the surgery was assessed in each patient by the VAS scale (1 to 10) at intervals of 24-48-72-96 hours. The soft tissue healing was clinically evaluated at 3, 7, 14, and 21 days after surgery by the same examiner surgeon, using the modified Healing Index (4 to 12). The mean value of postextraction pain was 3.2 ± 0.3 in the experimental sides and 4.1 ± 0.1 in the control sides. After 7 days from the extractions, the values of modified Healing Index in the experimental and control groups were, respectively, 4.8 ± 0.6 and 5.1 ± 0.9. The use of L-PRF in postextraction sockets filling can be proposed as a useful procedure in order to manage the postoperative pain and to promote the soft tissue healing process, reducing the early adverse effects of the inflammation. PMID:26273612

Homodyne impulse radar hidden object locator

DOEpatents

McEwan, T.E.

1996-04-30

An electromagnetic detector is designed to locate an object hidden behind a separator or a cavity within a solid object. The detector includes a PRF generator for generating 2 MHz pulses, a homodyne oscillator for generating a 2 kHz square wave, and for modulating the pulses from the PRF generator. A transmit antenna transmits the modulated pulses through the separator, and a receive antenna receives the signals reflected off the object. The receiver path of the detector includes a sample and hold circuit, an AC coupled amplifier which filters out DC bias level shifts in the sample and hold circuit, and a rectifier circuit connected to the homodyne oscillator and to the AC coupled amplifier, for synchronously rectifying the modulated pulses transmitted over the transmit antenna. The homodyne oscillator modulates the signal from the PRF generator with a continuous wave (CW) signal, and the AC coupled amplifier operates with a passband centered on that CW signal. The present detector can be used in several applications, including the detection of metallic and non-metallic objects, such as pipes, studs, joists, nails, rebars, conduits and electrical wiring, behind wood wall, ceiling, plywood, particle board, dense hardwood, masonry and cement structure. The detector is portable, light weight, simple to use, inexpensive, and has a low power emission which facilitates the compliance with Part 15 of the FCC rules. 15 figs.

Homodyne impulse radar hidden object locator

DOEpatents

McEwan, Thomas E.

1996-01-01

An electromagnetic detector is designed to locate an object hidden behind a separator or a cavity within a solid object. The detector includes a PRF generator for generating 2 MHz pulses, a homodyne oscillator for generating a 2 kHz square wave, and for modulating the pulses from the PRF generator. A transmit antenna transmits the modulated pulses through the separator, and a receive antenna receives the signals reflected off the object. The receiver path of the detector includes a sample and hold circuit, an AC coupled amplifier which filters out DC bias level shifts in the sample and hold circuit, and a rectifier circuit connected to the homodyne oscillator and to the AC coupled amplifier, for synchronously rectifying the modulated pulses transmitted over the transmit antenna. The homodyne oscillator modulates the signal from the PRF generator with a continuous wave (CW) signal, and the AC coupled amplifier operates with a passband centered on that CW signal. The present detector can be used in several applications, including the detection of metallic and non-metallic objects, such as pipes, studs, joists, nails, rebars, conduits and electrical wiring, behind wood wall, ceiling, plywood, particle board, dense hardwood, masonry and cement structure. The detector is portable, light weight, simple to use, inexpensive, and has a low power emission which facilitates the compliance with Part 15 of the FCC rules.

Determination of the DNA-binding characteristics of ethidium bromide, proflavine, and cisplatin by flow injection analysis: usefulness in studies on antitumor drugs.

PubMed

Alonso, A; Almendral, M J; Curto, Y; Criado, J J; Rodríguez, E; Manzano, J L

2006-08-15

Flow injection analysis was used to study the reactions occurring between DNA and certain compounds that bind to its double helix, deforming this and even breaking it, such that some of them (e.g., cisplatin) are endowed with antitumoral activity. Use of this technique in the merging zones and stopped-flow modes afforded data on the binding parameters and the kinetic characteristics of the process. The first compound studied was ethidium bromide (EtdBr), used as a fluorescent marker because its fluorescence is enhanced when it binds to DNA. The DNA-EtdBr binding parameters, the apparent intrinsic binding constant (0.31+/-0.02 microM(-1)), and the maximum number of binding sites per nucleotide (0.327+/-0.009) were determined. The modification introduced in these parameters by the presence of proflavine (Prf), a classic competitive inhibitor of the binding of EtdBr to the DNA double helix, was also studied, determining the value of the intrinsic binding constant of Prf (K(Prf) = 0.119+/-9x10(-3) microM(-1)). Finally, we determined the binding parameters between DNA and EtdBr in the presence of the antitumor agent cisplatin, a noncompetitive inhibitor of such binding. This provided information about the binding mechanism as well as the duration and activity of the binding of the compound in its pharmacological use.

Spatiotemporal evolution of cavitation dynamics exhibited by flowing microbubbles during ultrasound exposure.

PubMed

Choi, James J; Coussios, Constantin-C

2012-11-01

Ultrasound and microbubble-based therapies utilize cavitation to generate bioeffects, yet cavitation dynamics during individual pulses and across consecutive pulses remain poorly understood under physiologically relevant flow conditions. SonoVue(®) microbubbles were made to flow (fluid velocity: 10-40 mm/s) through a vessel in a tissue-mimicking material and were exposed to ultrasound [frequency: 0.5 MHz, peak-rarefactional pressure (PRP): 150-1200 kPa, pulse length: 1-100,000 cycles, pulse repetition frequency (PRF): 1-50 Hz, number of pulses: 10-250]. Radiated emissions were captured on a linear array, and passive acoustic mapping was used to spatiotemporally resolve cavitation events. At low PRPs, stable cavitation was maintained throughout several pulses, thus generating a steady rise in energy with low upstream spatial bias within the focal volume. At high PRPs, inertial cavitation was concentrated in the first 6.3 ± 1.3 ms of a pulse, followed by an energy reduction and high upstream bias. Multiple pulses at PRFs below a flow-dependent critical rate (PRF(crit)) produced predictable and consistent cavitation dynamics. Above the PRF(crit), energy generated was unpredictable and spatially biased. In conclusion, key parameters in microbubble-seeded flow conditions were matched with specific types, magnitudes, distributions, and durations of cavitation; this may help in understanding empirically observed in vivo phenomena and guide future pulse sequence designs.

Simultaneous coexpression of memory-related and effector-related genes by individual human CD8 T cells depends on antigen specificity and differentiation.

PubMed

Gupta, Bhawna; Iancu, Emanuela M; Gannon, Philippe O; Wieckowski, Sébastien; Baitsch, Lukas; Speiser, Daniel E; Rufer, Nathalie

2012-07-01

Phenotypic and functional cell properties are usually analyzed at the level of defined cell populations but not single cells. Yet, large differences between individual cells may have important functional consequences. It is likely that T-cell-mediated immunity depends on the polyfunctionality of individual T cells, rather than the sum of functions of responding T-cell subpopulations. We performed highly sensitive single-cell gene expression profiling, allowing the direct ex vivo characterization of individual virus-specific and tumor-specific T cells from healthy donors and melanoma patients. We have previously shown that vaccination with the natural tumor peptide Melan-A-induced T cells with superior effector functions as compared with vaccination with the analog peptide optimized for enhanced HLA-A*0201 binding. Here we found that natural peptide vaccination induced tumor-reactive CD8 T cells with frequent coexpression of both memory/homing-associated genes (CD27, IL7R, EOMES, CXCR3, and CCR5) and effector-related genes (IFNG, KLRD1, PRF1, and GZMB), comparable with protective Epstein-Barr virus-specific and cytomegalovirus-specific T cells. In contrast, memory/homing-associated and effector-associated genes were less frequently coexpressed after vaccination with the analog peptide. Remarkably, these findings reveal a previously unknown level of gene expression diversity among vaccine-specific and virus-specific T cells with the simultaneous coexpression of multiple memory/homing-related and effector-related genes by the same cell. Such broad functional gene expression signatures within antigen-specific T cells may be critical for mounting efficient responses to pathogens or tumors. In summary, direct ex vivo high-resolution molecular characterization of individual T cells provides key insights into the processes shaping the functional properties of tumor-specific and virus-specific T cells.

Project WILAS: Seismic imaging of crustal and upper mantle structures beneath the western Iberian Peninsula by means of the receiver-function technique

NASA Astrophysics Data System (ADS)

Dündar, Süleyman; Dias, Nuno A.; Silveira, Graça; Vinnik, Lev; Haberland, Christian

2013-04-01

An accurate knowledge of the structure of the earth's interior is of great importance to our understanding of tectonic processes. The WILAS-project (REF: PTDC/CTE-GIX/097946/2008) is a three-year collaborative project developed to study the subsurface structure of the western Iberian Peninsula, putting the main emphases on the lithosphere-asthenosphere system beneath the mainland of Portugal. The tectonic evolution of the target area has been driven by major plate-tectonic processes such as the historical opening of the Central Atlantic and the subsequent African-Eurasian convergence. Still, very little is known about the spatial structure of the continental collision. Within the framework of this research, a temporary network of 30 broadband three-component digital stations was operated between 2010 and 2012 in the target area. To carry out a large-scale structural analysis and facilitate a dense station-coverage for the area under investigation, the permanent Global Seismic Network stations, and temporary broadband stations deployed within the scope of the several seismic experiments (e.g. Doctar Network, Portuguese National Seismic Network), were included in the research analysis. In doing so, an unprecedented volume of high-quality data of a ca. 60X60 km density along with a combined network of 65 temporary and permanent broadband seismic stations are currently available for research purposes. One of the tasks of the WILAS research project has been a study of seismic velocity discontinuities beneath the western Iberian Peninsula region, up to a depth range of 700 km, utilizing the P- and S-receiver function techniques (PRF, SRF). Both techniques are based mainly on mode conversion of the elastic body-waves at an interface dividing the layers with different elastic properties. In the first phase of the project, PRF analysis was conducted in order to image the crust-mantle interface (Moho) and the mantle-transition-zone discontinuities at a depth of 410 km and 660 km beneath the area under investigation. While applying the common data processing steps (e.g., rotation, deconvolution and moveout-correction) to the selected data-set, we were able to create approximately 4.500 PRFs. The signals from the Moho, 410-km and 660-km discontinuities are clearly visible in many PRF stacks. The Moho depth range is from 26 to 34 km, with an average value of 29 km. No significant lateral variations in the depths of the "410-km" and "660-km" discontinuities have been identified so far. In the second phase of this project, the S-receiver-function technique will be applied in order to map the thickness of the underlying mantle lithosphere. Additionally, joint inversion of PRFs and waveforms of SKS will be used to investigate depth-localized azimuthal anisotropy and the related past and present mantle flows.

Platelet-rich fibrin: a boon in regenerative endodontics.

PubMed

Rebentish, Priyanka D; Umashetty, Girish; Kaur, Harpreet; Doizode, Trupthi; Kaslekar, Mithun; Chowdhury, Shouvik

2016-12-01

Research into regenerative dentistry has contributed momentum to the field of molecular biology. Periapical surgery aims at removing periapical pathology to achieve complete wound healing and regeneration of bone and periodontal tissue. Regenerative endodontic procedures are widely being added to the current armamentarium of pulp therapy procedures. The regenerative potential of platelets has been deliberated. Platelet-rich fibrin (PRF) is a wonderful tissue-engineering product and has recently gained much popularity due its promising results in wound healing bone induction. The features of this product are an attribute of platelets which, after cellular interactions, release growth factors and have shown application in diverse disciplines of dentistry. This paper is intended to shed light onto the various prospects of PRF and to provide clinical insight into regenerative endodontic therapy.

Platelet-rich fibrin, "a faster healing aid" in the treatment of combined lesions: A report of two cases.

PubMed

Karunakar, Parupalli; Prasanna, Jammula Surya; Jayadev, Matapathi; Shravani, Guniganti Sushma

2014-09-01

Anatomically the pulp and periodontium are connected through apical foramen, and the lateral, accessory, and furcal canals. Diseases of one tissue may affect the other. In the present case report with two cases, a primary periodontal lesion with secondary endodontic involvement is described. In both cases, root canal treatment was done followed by periodontal therapy with the use of platelet-rich fibrin (PRF) as the regenerative material of choice. PRF has been a breakthrough in the stimulation and acceleration of tissue healing. It is used to achieve faster healing of the intrabony defects. Absence of an intraradicular lesion, pain, and swelling, along with tooth stability and adequate radiographic bone fill at 9 months of follow-up indicated a successful outcome.

Platelet-rich fibrin, “a faster healing aid” in the treatment of combined lesions: A report of two cases

PubMed Central

Karunakar, Parupalli; Prasanna, Jammula Surya; Jayadev, Matapathi; Shravani, Guniganti Sushma

2014-01-01

Anatomically the pulp and periodontium are connected through apical foramen, and the lateral, accessory, and furcal canals. Diseases of one tissue may affect the other. In the present case report with two cases, a primary periodontal lesion with secondary endodontic involvement is described. In both cases, root canal treatment was done followed by periodontal therapy with the use of platelet-rich fibrin (PRF) as the regenerative material of choice. PRF has been a breakthrough in the stimulation and acceleration of tissue healing. It is used to achieve faster healing of the intrabony defects. Absence of an intraradicular lesion, pain, and swelling, along with tooth stability and adequate radiographic bone fill at 9 months of follow-up indicated a successful outcome. PMID:25425831

Evaluation experimentale et theorique du comportement a la flexion de nouveaux poteaux en materiaux composites

NASA Astrophysics Data System (ADS)

Metiche, Slimane

La demande croissante en poteaux pour les differents reseaux d'electricite et de telecommunications a rendu necessaire l'utilisation de materiaux innovants, qui preservent l'environnement. La majorite des poteaux electriques existants au Canada ainsi qu'a travers le monde, sont fabriques a partir de materiaux traditionnels tel que le bois, le beton ou l'acier. Les motivations des industriels et des chercheurs a penser a d'autres solutions sont diverses, citons entre autre: La limitation en longueur des poteaux en bois ainsi que la vulnerabilite des poteaux fabriques en beton ou en acier aux agressions climatiques. Les nouveaux poteaux en materiaux composites se presentent comme de bons candidats a cet effet, cependant; leur comportement structural n'est pas connu et des etudes theoriques et experimentales approfondies sont necessaires avant leur mise en marche a grande echelle. Un programme de recherche intensif comportant plusieurs projets experimentaux, analytiques et numeriques est en cours a l'Universite de Sherbrooke afin d'evaluer le comportement a court et a long termes de ces nouveaux poteaux en Polymeres Renforces de Fibres (PRF). C'est dans ce contexte que s'inscrit la presente these, et notre recherche vise a evaluer le comportement a la flexion de nouveaux poteaux tubulaires coniques fabriques en materiaux composites par enroulement filamentaire et ce, a travers une etude theorique, ainsi qu'a travers une serie d'essais de flexion en "grandeur reelle" afin de comprendre le comportement structural de ces poteaux, d'optimiser la conception et de proposer une procedure de dimensionnement pour les utilisateurs. Les poteaux en Polymeres Renforces de Fibres (PRF) etudies dans cette these sont fabriques avec une resine epoxyde renforcee de fibres de verre type E. Chaque type poteaux est constitue principalement de trois zones ou les proprietes geometriques (epaisseur, diametre) et les proprietes mecaniques sont differentes d'une zone a l'autre. La difference entre ces proprietes est due au nombre de couches utilisees dans chaque zone ainsi qu'a l'orientation des fibres de chaque couche. Un total de vingt-trois prototypes de dimensions differentes; ont ete testes en flexion jusqu'a la rupture. Deux types de fibres de verre de masses lineaires differentes, ont ete utilisees afin d'evaluer l'effet du type de fibres sur le comportement a la flexion. Un nouveau montage experimental permettant de tester tous les types de poteaux en PRF a ete dimensionne et fabrique selon les recommandations decrites dans les normes ASTM D 4923-01 et ANSI C 136.20-2005. Un modele analytique base sur la theorie des poutres en elasticite lineaire est propose dans cette these. Ce modele predit avec une bonne precision le comportement experimental charge---deflexion ainsi que la deflexion maximale au sommet des poteaux en PRF; constitues de plusieurs zones de caracteristiques geometriques et mecaniques differentes. Une procedure de dimensionnement des poteaux en PRF, basee sur les resultats experimentaux obtenus dans le cadre de la presente these, est egalement proposee. Les resultats obtenus dans le cadre de la presente these permettront le developpement et l'amelioration des regles de conception utiles et pratiques a l'usage des concepteurs et des industriels du domaine des poteaux en PRF. Les retombees de cette recherche sont a la fois economiques et technologiques, car les resultats obtenus constitueront une banque de donnees qui contribueront au developpement des normes de calcul, et par consequent a l'optimisation des materiaux utilises, et serviront a valider de futurs resultats et modeles theoriques.

Porcine skin damage thresholds for pulsed nanosecond-scale laser exposure at 1064-nm

NASA Astrophysics Data System (ADS)

DeLisi, Michael P.; Peterson, Amanda M.; Noojin, Gary D.; Shingledecker, Aurora D.; Tijerina, Amanda J.; Boretsky, Adam R.; Schmidt, Morgan S.; Kumru, Semih S.; Thomas, Robert J.

2018-02-01

Pulsed high-energy lasers operating in the near-infrared (NIR) band are increasingly being used in medical, industrial, and military applications, but there are little available experimental data to characterize their hazardous effects on skin tissue. The current American National Standard for the Safe Use of Lasers (ANSI Z136.1-2014) defines the maximum permissible exposure (MPE) on the skin as either a single-pulse or total exposure time limit. This study determined the minimum visible lesion (MVL) damage thresholds in Yucatan miniature pig skin for the single-pulse case and several multiple-pulse cases over a wide range of pulse repetition frequencies (PRFs) (10, 125, 2,000, and 10,000 Hz) utilizing nanosecond-scale pulses (10 or 60 ns). The thresholds are expressed in terms of the median effective dose (ED50) based on varying individual pulse energy with other laser parameters held constant. The results confirm a decrease in MVL threshold as PRF increases for exposures with a constant number of pulses, while also noting a PRF-dependent change in the threshold as a function of the number of pulses. Furthermore, this study highlights a change in damage mechanism to the skin from melanin-mediated photomechanical events at high irradiance levels and few numbers of pulses to bulk tissue photothermal additivity at lower irradiance levels and greater numbers of pulses. The observed trends exceeded the existing exposure limits by an average factor of 9.1 in the photothermally-damaged cases and 3.6 in the photomechanicallydamaged cases.

Report on the emergency response to the event on May 14, 1997, at the plutonuim reclamation facility, Hanford Site, Richland,Washington

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shoop, D.S.

1997-08-20

On the evening of May 14,1997, a chemical explosion Occurred at the Plutonium Reclamation Facility (PRF) in the 200 West Area(200-W) of the Hanford Site. The event warranted the declaration of an Alert emergency, activation of the Hanford Emergency Response Organization (BRO), and notification of offsite agencies. As a result of the emergency declaration, a subsequent evaluation was conducted to assess: 9 the performance of the emergency response organization o the occupational health response related to emergency activities o event notifications to offsite and environmental agencies. Additionally, the evaluation was designed to: 9 document the chronology of emergency and occupationalmore » health responses and environmental notifications connected with the explosion at the facility 0 assess the adequacy of the Hanford Site emergency preparedness activities; response readiness; and emergency management actions, occupational health, and environmental actions 0 provide an analysis of the causes of the deficiencies and weaknesses in the preparedness and response system that have been identified in the evaluation of the response a assign organizational responsibility to correct deficiencies and weaknesses a improve future performance 0 adjust elements of emergency implementing procedures and emergency preparedness activities.« less

Listeria-vectored vaccine expressing the Mycobacterium tuberculosis 30 kDa major secretory protein via the constitutively active prfA* regulon boosts BCG efficacy against tuberculosis.

PubMed

Jia, Qingmei; Dillon, Barbara Jane; Masleša-Galić, Saša; Horwitz, Marcus A

2017-06-19

A potent vaccine against tuberculosis, one of the world's deadliest diseases, is needed to enhance the immunity of people worldwide, most of whom have been vaccinated with the partially effective BCG vaccine. Here we investigate novel live attenuated recombinant Listeria monocytogenes (rLm) vaccines expressing the Mycobacterium tuberculosis (Mtb) 30 kDa major secretory protein (r30/Ag85B) (rLm30) as heterologous booster vaccines in animals primed with BCG. Using three attenuated Lm vectors, rLm Δ actA (LmI), rLm Δ actA Δ inlB (LmII), and rLm Δ actA Δ inlB prfA * (LmIII), we constructed five rLm30 vaccine candidates expressing the r30 linked in-frame to the Lm Listeriolycin O signal sequence and driven by the hly promoter (h30) or linked in-frame to the ActA N-terminus and driven by the actA promoter (a30). All five rLm30 vaccines secreted r30 in broth and macrophages; while rLm expressing r30 via a constitutively active prfA * regulon (rLmIII/a30) expressed the greatest amount of r30 in broth culture, all five rLm vaccines expressed equivalent amounts of r30 in infected macrophages. In comparative studies, boosting BCG-immunized mice with rLmIII/a30 induced the strongest antigen-specific T-cell responses, including splenic and lung polyfunctional CD4+ T-cells expressing the three cytokines of interferon-gamma (IFN-γ), tumor necrosis factor-alpha (TNF-α), and interleukin-2 (IL-2) ( P < 0.001) and splenic and lung CD8+ T-cells expressing IFN-γ ( P < 0.0001). In mice and guinea pigs, rLmIII/a30 and rLmI/h30 vaccines were generally more potent booster vaccines than r30 in adjuvant and a recombinant adenovirus vaccine expressing r30. In a setting in which BCG alone was highly immunoprotective, boosting mice with rLmIII/a30, the most potent of the vaccines, significantly enhanced protection against aerosolized Mtb ( P <0.01). Copyright © 2017 American Society for Microbiology.

The intrinsic cephalosporin resistome of Listeria monocytogenes in the context of stress response, gene regulation, pathogenesis and therapeutics.

PubMed

Krawczyk-Balska, A; Markiewicz, Z

2016-02-01

Intrinsic resistance to antibiotics is a serious therapeutic problem in the case of many bacterial species. The Gram-positive human pathogen Listeria monocytogenes is intrinsically resistant to broad spectrum cephalosporin antibiotics, which are commonly used in therapy of bacterial infections. Besides three penicillin-binding proteins the intrinsic cephalosporin resistome of L. monocytogenes includes multidrug resistance transporter transporters, proteins involved in peptidoglycan biosynthesis and modification, cell envelope proteins with structural or general detoxification function, cytoplasmic proteins with unknown function and regulatory proteins. Analysis of the regulation of the expression of genes involved in the intrinsic resistance of L. monocytogenes to cephalosporins highlights the high complexity of control of the intrinsic resistance phenotype. The regulation of the transcription of the intrinsic resistome determinants involves the activity of eight regulators, namely LisR, CesR, LiaR, VirR, σ(B) , σ(H) , σ(L) and PrfA, of which the most prominent role play LisR, CesR and σ(B) . Furthermore, the vast majority of the intrinsic resistome determinants contribute to the tolerance of different stress conditions and virulence. A study indicates that O-acetyltransferase OatA is the most promising candidate for co-drug development since an agent targeting OatA should sensitize L. monocytogenes to certain antibiotics, therefore improving the efficacy of listeriosis treatment as well as food preservation measures. © 2015 The Society for Applied Microbiology.

Comparative genetics of disease resistance within the solanaceae.

PubMed Central

Grube, R C; Radwanski, E R; Jahn, M

2000-01-01

Genomic positions of phenotypically defined disease resistance genes (R genes) and R gene homologues were analyzed in three solanaceous crop genera, Lycopersicon (tomato), Solanum (potato), and Capsicum (pepper). R genes occurred at corresponding positions in two or more genomes more frequently than expected by chance; however, in only two cases, both involving Phytophthora spp., did genes at corresponding positions have specificity for closely related pathogen taxa. In contrast, resistances to Globodera spp., potato virus Y, tobacco mosaic virus, and tomato spotted wilt virus were mapped in two or more genera and did not occur in corresponding positions. Without exception, pepper homologues of the cloned R genes Sw-5, N, Pto, Prf, and I2 were found in syntenous positions in other solanaceous genomes and in some cases also mapped to additional positions near phenotypically defined solanaceous R genes. This detailed analysis and synthesis of all available data for solanaceous R genes suggests a working hypothesis regarding the evolution of R genes. Specifically, while the taxonomic specificity of host R genes may be evolving rapidly, general functions of R alleles (e.g., initiation of resistance response) may be conserved at homologous loci in related plant genera. PMID:10835406

Viral hemorrhagic septicaemia virus (VHSV) up-regulates the cytotoxic activity and the perforin/granzyme pathway in the rainbow trout RTS11 cell line.

PubMed

Ordás, M C; Cuesta, A; Mercado, L; Bols, N C; Tafalla, C

2011-08-01

A survey of immune-relevant genes that might be up-regulated in response to viral hemorrhagic septicaemia virus (VHSV) in the rainbow trout monocyte-macrophage cell line, RTS11, unexpectedly revealed an increased expression of perforin (PRF) and granzyme (GRZ) genes, which represent components of the major cytotoxic pathway. The natural killer-enhancing factor (NKEF), also known to modulate cytotoxic activity, was up-regulated at the gene but strikingly down-regulated at protein level. The expression of these genes was not affected in head kidney leukocytes (HKLs) infected with VHSV, leading us to evaluate the potential cytotoxic activity of RTS11 and HKLs. For the first time, the cytotoxic activity of RTS11 against xenogeneic targets has been demonstrated, although this was modest relative to HKLs. Yet the activity in RTS11 was significantly increased by VHSV, as in HKLs. This cytotoxic activity elicited by viral infection appeared to require viral gene expression because inactivated VHSV failed to increase RTS11 cytotoxic activity. As for other immune functions, RTS11 cells provide a model for further studying cytotoxic activities of fish monocyte-macrophages. Copyright © 2011 Elsevier Ltd. All rights reserved.

Unperturbed Cytotoxic Lymphocyte Phenotype and Function in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome Patients

PubMed Central

Theorell, Jakob; Bileviciute-Ljungar, Indre; Tesi, Bianca; Schlums, Heinrich; Johnsgaard, Mette Sophie; Asadi-Azarbaijani, Babak; Bolle Strand, Elin; Bryceson, Yenan T.

2017-01-01

Myalgic encephalomyelitis or chronic fatigue syndrome (ME/CFS) is a debilitating disorder linked to diverse intracellular infections as well as physiological stress. Cytotoxic lymphocytes combat intracellular infections. Their function is attenuated by stress. Despite numerous studies, the role of cytotoxic lymphocytes in ME/CFS remains unclear. Prompted by advances in the understanding of defects in lymphocyte cytotoxicity, the discovery of adaptive natural killer (NK) cell subsets associated with certain viral infections, and compelling links between stress, adrenaline, and cytotoxic lymphocyte function, we reassessed the role of cytotoxic lymphocytes in ME/CFS. Forty-eight patients from two independent cohorts fulfilling the Canada 2003 criteria for ME/CFS were evaluated with respect to cytotoxic lymphocyte phenotype and function. Results were compared to values from matched healthy controls. Reproducible differences between patients and controls were not found in cytotoxic lymphocyte numbers, cytotoxic granule content, activation status, exocytotic capacity, target cell killing, or cytokine production. One patient expressed low levels of perforin, explained by homozygosity for the PRF1 p.A91V variant. However, overall, this variant was present in a heterozygous state at the expected population frequency among ME/CFS patients. No single patient displayed any pathological patterns of cellular responses. Increased expansions of adaptive NK cells or deviant cytotoxic lymphocyte adrenaline-mediated inhibition were not observed. In addition, supervised dimensionality reduction analyses of the full, multidimensional datasets did not reveal any reproducible patient/control discriminators. In summary, employing sensitive assays and analyses for quantification of cytotoxic lymphocyte differentiation and function, cytotoxicity lymphocyte aberrances were not found among ME/CFS patients. These assessments of cytotoxic lymphocytes therefore do not provide useful biomarkers for the diagnosis of ME/CFS. PMID:28694809

Progeria 101/FAQ

MedlinePlus

... Culture Protocols Immortalized Cell Culture Protocols Induced Pluripotent Stem Cells PRF Cell and Tissue Bank Publications Research Funding Opportunities Grant Application Application Deadlines Grants Funded Close Meet The Kids Meet The Kids Our Ambassadors Find The Other ...

Isolation and characterization of atypical Listeria monocytogenes associated with a canine urinary tract infection.

PubMed

Palerme, Jean-Sébastien; Pan, Po Ching; Parsons, Cameron T; Kathariou, Sophia; Ward, Todd J; Jacob, Megan E

2016-09-01

Listeria monocytogenes, a well-described cause of encephalitis and abortion in ruminants and of food-borne illness in humans, is rarely associated with disease in companion animals. A case of urinary tract infection associated with an atypical, weakly hemolytic L. monocytogenes strain is described in a diabetic dog. The serotype of the L. monocytogenes isolate was determined to be 1/2a (3a), with the multilocus genotyping pattern 2.72_1/2a. A nucleotide substitution (Gly145Asp) was detected at residue 145 in the promoter prfA region. This residue is within the critical helix-turn-helix motif of PrfA. The source of the L. monocytogenes strain remains unknown, and the dog recovered after a 4-week course of cephalexin (30 mg/kg orally twice daily). © 2016 The Author(s).

Electrostatic Evaluation: SCAPE Suit Materials

NASA Technical Reports Server (NTRS)

Buhler, Charles; Calle, Carlos

2005-01-01

The surface resistivity tests are performed per the requirements of the ESD Association Standard Test Method ESD STM11.11*. These measurements are taken using a PRS-801 resistance system with an Electro Tech System (ETS) PRF-911 concentric ring resistance probe. The tests require a five pound weight on top of cylindrical electrodes and were conducted at both ambient and low humidity conditions. In order for materials to "pass" resistivity tests the surface of the materials must either be conductive or statically dissipative otherwise the materials "fail" ESD. Volume resistivity tests are also conducted to measure conductivity through the material as opposed to conductivity along the surface. These tests are conducted using the same PRS-801 resistance system with the Electro Tech System PRF-911 concentric ring resistance probe but are performed in accordance with ESD Association Standard Test Method ESD STM11.l2**.

Evaluation of thermometric monitoring for intradiscal laser ablation in an open 1.0 T MR scanner.

PubMed

Wonneberger, Uta; Schnackenburg, Bernhard; Wlodarczyk, Waldemar; Rump, Jens; Walter, Thula; Streitparth, Florian; Teichgräber, Ulf Karl Mart

2010-01-01

The purpose of this study was to evaluate different methods of magnetic resonance thermometry (MRTh) for the monitoring of intradiscal laser ablation therapy in an open 1.0 Tesla magnetic resonance (MR) scanner. MRTh methods based on the two endogenous MR temperature indicators of spin-lattice relaxation time T1 and water proton resonance frequency (PRF) shift were optimised and compared in vitro. For the latter, we measured the effective spin-spin relaxation times T2* in intervertebral discs of volunteers. Then we compared four gradient echo-based imaging techniques to monitor laser ablations in human disc specimens. Criteria of assessment were outline of anatomic detail, immunity against needle artefacts, signal-to-noise ratio (SNR) and accuracy of the calculated temperature. T2* decreased in an inverse and almost linear manner with the patients' age (r = 0.9) from 70 to 30 ms (mean of 49 ms). The optimum image quality (anatomic details, needle artefacts, SNR) and temperature accuracy (+/-1.09 degrees C for T1-based and +/-1.11 degrees C for PRF-based MRTh) was achieved with a non-spoiled gradient-echo sequence with an echo time of TE = 10 ms. Combination of anatomic and thermometric non-invasive monitoring of laser ablations in the lumbar spine is feasible. The temperature accuracy of the investigated T1- and PRF-based MRTh methods in vitro is high enough and promises to be reliable in vivo as well.

Mechanical Testing of MLCCs

NASA Technical Reports Server (NTRS)

Teverovsky, Alexander A.

2016-01-01

Cracking of multilayer ceramic capacitors, MLCCs, remains a serious problem for space systems. This problem increases substantially for large size capacitors and in cases when manual soldering is involved or the system experiences mechanical shock or vibration. In any case, a fracture occurs when the sum of external and internal mechanical stresses exceeds the strength of the part. To reduce the probability of cracking, the level of stress should be reduced, e.g. by optimizing the assembly workmanship and rules for board design, and the strength of the parts increased by selecting the most mechanically robust capacitors. The latter might possibly be achieved by selecting MLCCs based on the in-situ measurements of mechanical characteristics using four types of tests: flexural strength, hardness, fracture toughness, and flex bend testing. Note that military specifications MIL-PRF-123 and MIL-PRF-55681 do not have requirements for mechanical testing of the parts. However, specifications for automotive industry components employ two types of mechanical tests: beam load (break strength) test per AEC-Q200-003 and board flex test per AEC-Q200-005. A recent military specification for thin dielectric capacitors, MIL-PRF-32535, has one mechanical test, board flex testing, that is similar to AEC-Q200-005. The purpose of this report was assessment of the efficiency of different mechanical tests for selection robust capacitors and comparison of mechanical characteristics of Base Metal Electrode (BME) and Precious Metal Electrode (PME) capacitors. The report has three parts related to the first three mechanical tests mentioned above.

Commercial mode-locked vertical external cavity surface emitting lasers

NASA Astrophysics Data System (ADS)

Lubeigt, Walter; Bialkowski, Bartlomiej; Lin, Jipeng; Head, C. Robin; Hempler, Nils; Maker, Gareth T.; Malcolm, Graeme P. A.

2017-02-01

In recent years, M Squared Lasers have successfully commercialized a range of mode-locked vertical external cavity surface emitting lasers (VECSELs) operating between 920-1050nm and producing picosecond-range pulses with average powers above 1W at pulse repetition frequencies (PRF) of 200MHz. These laser products offer a low-cost, easy-to-use and maintenance-free tool for the growing market of nonlinear microscopy. However, in order to present a credible alternative to ultrafast Ti-sapphire lasers, pulse durations below 200fs are required. In the last year, efforts have been directed to reduce the pulse duration of the Dragonfly laser system to below 200fs with a target average power above 1W at a PRF of 200MHz. This paper will describe and discuss the latest efforts undertaken to approach these targets in a laser system operating at 990nm. The relatively low PRF operation of Dragonfly lasers represents a challenging requirement for mode-locked VECSELs due to the very short upper state carrier lifetime, on the order of a few nanoseconds, which can lead to double pulsing behavior in longer cavities as the time between consecutive pulses is increased. Most notably, the design of the Dragonfly VECSEL cavity was considerably modified and the laser system extended with a nonlinear pulse stretcher and an additional compression stage. The improved Dragonfly laser system achieved pulse duration as short as 130fs with an average power of 0.85W.

Accurate MR thermometry by hyperpolarized 129 Xe.

PubMed

Zhang, Le; Burant, Alex; McCallister, Andrew; Zhao, Victor; Koshlap, Karl M; Degan, Simone; Antonacci, Michael; Branca, Rosa Tamara

2017-09-01

To investigate the temperature dependence of the resonance frequency of lipid-dissolved xenon (LDX) and to assess the accuracy of LDX-based MR thermometry. The chemical shift temperature dependence of water protons, methylene protons, and LDX was measured from samples containing tissues with varying fat contents using a high-resolution NMR spectrometer. LDX results were then used to acquire relative and absolute temperature maps in vivo and the results were compared with PRF-based MR thermometry. The temperature dependence of proton resonance frequency (PRF) is strongly affected by the specific distribution of water and fat. A redistribution of water and fat compartments can reduce the apparent temperature dependence of the water chemical shift from -0.01 ppm/°C to -0.006 ppm, whereas the LDX chemical shift shows a consistent temperature dependence of -0.21 ppm/°C. The use of the methylene protons resonance frequency as internal reference improves the accuracy of LDX-based MR thermometry, but degrades that of PRF-based MR thermometry, as microscopic susceptibility gradients affected lipid and water spins differently. The LDX resonance frequency, with its higher temperature dependence, provides more accurate and precise temperature measurements, both in vitro and in vivo. More importantly, the resonance frequency of nearby methylene protons can be used to extract absolute temperature information. Magn Reson Med 78:1070-1079, 2017. © 2016 International Society for Magnetic Resonance in Medicine. © 2016 International Society for Magnetic Resonance in Medicine.

Progeria Research Foundation Diagnostic Testing Program

MedlinePlus

... Culture Protocols Immortalized Cell Culture Protocols Induced Pluripotent Stem Cells PRF Cell and Tissue Bank Publications Research Funding Opportunities Grant Application Application Deadlines Grants Funded Close Meet The Kids Meet The Kids Our Ambassadors Find The Other ...

Multiparametric fat-water separation method for fast chemical-shift imaging guidance of thermal therapies.

PubMed

Lin, Jonathan S; Hwang, Ken-Pin; Jackson, Edward F; Hazle, John D; Stafford, R Jason; Taylor, Brian A

2013-10-01

A k-means-based classification algorithm is investigated to assess suitability for rapidly separating and classifying fat/water spectral peaks from a fast chemical shift imaging technique for magnetic resonance temperature imaging. Algorithm testing is performed in simulated mathematical phantoms and agar gel phantoms containing mixed fat/water regions. Proton resonance frequencies (PRFs), apparent spin-spin relaxation (T2*) times, and T1-weighted (T1-W) amplitude values were calculated for each voxel using a single-peak autoregressive moving average (ARMA) signal model. These parameters were then used as criteria for k-means sorting, with the results used to determine PRF ranges of each chemical species cluster for further classification. To detect the presence of secondary chemical species, spectral parameters were recalculated when needed using a two-peak ARMA signal model during the subsequent classification steps. Mathematical phantom simulations involved the modulation of signal-to-noise ratios (SNR), maximum PRF shift (MPS) values, analysis window sizes, and frequency expansion factor sizes in order to characterize the algorithm performance across a variety of conditions. In agar, images were collected on a 1.5T clinical MR scanner using acquisition parameters close to simulation, and algorithm performance was assessed by comparing classification results to manually segmented maps of the fat/water regions. Performance was characterized quantitatively using the Dice Similarity Coefficient (DSC), sensitivity, and specificity. The simulated mathematical phantom experiments demonstrated good fat/water separation depending on conditions, specifically high SNR, moderate MPS value, small analysis window size, and low but nonzero frequency expansion factor size. Physical phantom results demonstrated good identification for both water (0.997 ± 0.001, 0.999 ± 0.001, and 0.986 ± 0.001 for DSC, sensitivity, and specificity, respectively) and fat (0.763 ± 0.006, 0.980 ± 0.004, and 0.941 ± 0.002 for DSC, sensitivity, and specificity, respectively). Temperature uncertainties, based on PRF uncertainties from a 5 × 5-voxel ROI, were 0.342 and 0.351°C for pure and mixed fat/water regions, respectively. Algorithm speed was tested using 25 × 25-voxel and whole image ROIs containing both fat and water, resulting in average processing times per acquisition of 2.00 ± 0.07 s and 146 ± 1 s, respectively, using uncompiled MATLAB scripts running on a shared CPU server with eight Intel Xeon(TM) E5640 quad-core processors (2.66 GHz, 12 MB cache) and 12 GB RAM. Results from both the mathematical and physical phantom suggest the k-means-based classification algorithm could be useful for rapid, dynamic imaging in an ROI for thermal interventions. Successful separation of fat/water information would aid in reducing errors from the nontemperature sensitive fat PRF, as well as potentially facilitate using fat as an internal reference for PRF shift thermometry when appropriate. Additionally, the T1-W or R2* signals may be used for monitoring temperature in surrounding adipose tissue.

A comparison of efficiency of biopolymer and allograft matrix with autogenous gingival graft used in root coverage procedure.

PubMed

Fathima, K Hameed; Harish, V S

2015-08-01

Severe surgical techniques have been introduced to augment gingival tissue dimensions like the free gingival graft, free connective grafts, etc., However, both the techniques are associated with significant patient morbidity due to the secondary surgical site. In order to overcome these postsurgical complications, acellular dermal allografts have been used as a substitute for the palatal donor tissue yielding clinically comparable results. However, the cost and origin of the material raises concern regarding the frequent use of the material. As an improved alternative to above-mentioned graft material, the use of platelet-rich fibrin (PRF) and collagen matrices has been promoted in the recent past. The objective of this illustrative case report is to test the efficacy of collagen matrix, PRF to augment attached gingiva and to assess the esthetic outcome when compared to the standard treatment with free autogenous graft.

A comparison of efficiency of biopolymer and allograft matrix with autogenous gingival graft used in root coverage procedure

PubMed Central

Fathima, K. Hameed; Harish, V. S.

2015-01-01

Severe surgical techniques have been introduced to augment gingival tissue dimensions like the free gingival graft, free connective grafts, etc., However, both the techniques are associated with significant patient morbidity due to the secondary surgical site. In order to overcome these postsurgical complications, acellular dermal allografts have been used as a substitute for the palatal donor tissue yielding clinically comparable results. However, the cost and origin of the material raises concern regarding the frequent use of the material. As an improved alternative to above-mentioned graft material, the use of platelet-rich fibrin (PRF) and collagen matrices has been promoted in the recent past. The objective of this illustrative case report is to test the efficacy of collagen matrix, PRF to augment attached gingiva and to assess the esthetic outcome when compared to the standard treatment with free autogenous graft. PMID:26538946

The use of platelet-rich fibrin as a hemostatic material in oral soft tissues.

PubMed

de Almeida Barros Mourão, Carlos Fernando; Calasans-Maia, Mônica Diuana; de Mello Machado, Rafael Coutinho; de Brito Resende, Rodrigo Figueiredo; Alves, Gutemberg Gomes

2018-06-26

The control of postoperative bleeding represents one of the main intercurrent events associated with soft tissue surgical procedures in the oral cavity. In this context, platelet-rich fibrin (PRF) membranes are materials with great potential for optimizing soft tissue healing and induction of hemostasis. This interventional case series describes the treatment of 10 patients with excisional biopsy of benign oral cavity lesions, following a screening sequence at the surgery clinic of a Brazilian dental school between the years of 2015 and 2017. After treatment with PRF, patients presented mean time for postoperative hemostasis of 10.3 ± 2.5 s, requiring the average use of three membranes to cover the surgical area. The results suggest that the use of platelet-rich fibrin membranes may represent a feasible alternative hemostatic material for the treatment of oral lesions.

A subcortical inhibitory signal for behavioral arrest in the thalamus

PubMed Central

Dugué, Guillaume P.; Bokor, Hajnalka; Rousseau, Charly V.; Maglóczky, Zsófia; Havas, László; Hangya, Balázs; Wildner, Hendrik; Zeilhofer, Hanns Ulrich; Dieudonné, Stéphane; Acsády, László

2016-01-01

Organization of behavior requires rapid coordination of brainstem and forebrain activity. The exact mechanisms of effective communication between these regions are presently unclear. The intralaminar thalamus (IL) probably serves as a central hub in this circuit by connecting the critical brainstem and forebrain areas. Here we found that GABAergic/glycinergic fibers ascending from the pontine reticular formation (PRF) of the brainstem evoke fast and reliable inhibition in the IL thalamus via large, multisynaptic terminals. This inhibition was fine-tuned through heterogeneous GABAergic/glycinergic receptor ratios expressed at individual synapses. Optogenetic activation of PRF axons in the IL of freely moving mice led to behavioral arrest and transient interruption of awake cortical activity. An afferent system with comparable morphological features was also found in the human IL. These data reveal an evolutionarily conserved ascending system which gates forebrain activity through fast and powerful synaptic inhibition of the IL thalamus. PMID:25706472

KSC-2013-3066

NASA Image and Video Library

2013-07-19

CAPE CANAVERAL, Fla. – NASA’s Kennedy Space Center in Florida has signed a new partnership agreement with Ballistic Recovery Systems Inc., or BRS Aerospace of Miami, Fla., for use of the Parachute Refurbishment Facility, or PRF. From left, are Rob Salonen, director of Business Development with the Economic Development Commission, EDC, of Florida’s Space Coast Jim Barfield, EDC treasurer Larry Williams, president and CEO of BRS Aerospace and Center Director Bob Cabana. The PRF previously was used during NASA’s Space Shuttle Program to manufacture and refurbish the solid rocket booster parachutes. Because of NASA’s transition from the shuttle to future commercial and government mission activities, the agreement allows NASA to preserve the unique facility capabilities for future spaceflight projects. Kennedy’s Center Planning and Development team and the Economic Development Commission of Florida’s Space Coast worked with BRS Aerospace to establish the agreement. For more information about BRS Aerospace, visit http://www.brsparachutes.com. Photo credit: NASA/Jim Grossmann

KSC-2013-3064

NASA Image and Video Library

2013-07-19

CAPE CANAVERAL, Fla. – At NASA’s Kennedy Space Center in Florida, Director Bob Cabana, at right, shakes hands with Larry Williams, president and CEO of Ballistic Recovery Systems Inc., or BRS Aerospace of Miami, Fla., after signing a new partnership agreement for use of the Parachute Refurbishment Facility, or PRF. Under a 10-year lease agreement, BRS Aerospace will operate and maintain the facility. The PRF previously was used during NASA’s Space Shuttle Program to manufacture and refurbish the solid rocket booster parachutes. Because of NASA’s transition from the shuttle to future commercial and government mission activities, the agreement allows NASA to preserve the unique facility capabilities for future spaceflight projects. Kennedy’s Center Planning and Development team and the Economic Development Commission of Florida’s Space Coast worked with BRS Aerospace to establish the agreement. For more information about BRS Aerospace, visit http://www.brsparachutes.com. Photo credit: NASA/Jim Grossmann

KSC-2013-3065

NASA Image and Video Library

2013-07-19

CAPE CANAVERAL, Fla. – At NASA’s Kennedy Space Center in Florida, Director Bob Cabana, at right, shakes hands with Larry Williams, president and CEO of Ballistic Recovery Systems Inc., or BRS Aerospace of Miami, Fla., after signing a new partnership agreement for use of the Parachute Refurbishment Facility, or PRF. Under a 10-year lease agreement, BRS Aerospace will operate and maintain the facility. The PRF previously was used during NASA’s Space Shuttle Program to manufacture and refurbish the solid rocket booster parachutes. Because of NASA’s transition from the shuttle to future commercial and government mission activities, the agreement allows NASA to preserve the unique facility capabilities for future spaceflight projects. Kennedy’s Center Planning and Development team and the Economic Development Commission of Florida’s Space Coast worked with BRS Aerospace to establish the agreement. For more information about BRS Aerospace, visit http://www.brsparachutes.com. Photo credit: NASA/Jim Grossmann

Plectin deficiency in liver cancer cells promotes cell migration and sensitivity to sorafenib treatment.

PubMed

Cheng, Chiung-Chi; Chao, Wei-Ting; Liao, Chen-Chun; Tseng, Yu-Hui; Lai, Yen-Chang Clark; Lai, Yih-Shyong; Hsu, Yung-Hsiang; Liu, Yi-Hsiang

2018-01-02

Plectin involved in activation of kinases in cell signaling pathway and plays important role in cell morphology and migration. Plectin knockdown promotes cell migration by activating focal adhesion kinase and Rac1-GTPase activity in liver cells. Sorafenib is a multi-targeting tyrosine kinase inhibitor that improves patient survival on hepatocellular carcinoma. The aim of this study is to investigate the correlation between the expression of plectin and cell migration as well as the sensitivity of hepatoma cell lines exposing to sorafenib. Hepatoma cell lines PLC/PRF/5 and HepG2 were used to examine the level of plectin expression and cell migration in comparison with Chang liver cell line. In addition, sensitivity of the 3 cell lines to sorafenib treatment was also measured. Expression of plectin was lower in PLC/PRF/5 and HepG2 hepatoma cells than that of Chang liver cells whereas HepG2 and PLC/PRF/5 cells exhibit higher rate of cell migration in trans-well migration assay. Immunohistofluorecent staining on E-cadherin revealed the highest rate of collective cell migration in HepG2 cells and the lowest was found in Chang liver cells. Likewise, HepG2 cell line was most sensitive to sorafenib treatment and Chang liver cells exhibited the least sensitivity. The drug sensitivity to sorafenib treatment showed inverse correlation with the expression of plectin. We suggest that plectin deficiency and increased E-cadherin in hepatoma cells were associated with higher rates of cell motility, collective cell migration as well as higher drug sensitivity to sorafenib treatment.

Dual-species biofilm of Listeria monocytogenes and Escherichia coli on stainless steel surface.

PubMed

de Grandi, Aline Zago; Pinto, Uelinton Manoel; Destro, Maria Teresa

2018-04-12

Listeria monocytogenes is a Gram-positive bacterium commonly associated with foodborne diseases. Due its ability to survive under adverse environmental conditions and to form biofilm, this bacterium is a major concern for the food industry, since it can compromise sanitation procedures and increase the risk of post-processing contamination. Little is known about the interaction between L. monocytogenes and Gram-negative bacteria on biofilm formation. Thus, in order to evaluate this interaction, Escherichia coli and L. monocytogenes were tested for their ability to form biofilms together or in monoculture. We also aimed to evaluate the ability of L. monocytogenes 1/2a and its isogenic mutant strain (ΔprfA ΔsigB) to form biofilm in the presence of E. coli. We assessed the importance of the virulence regulators, PrfA and σ B , in this process since they are involved in many aspects of L. monocytogenes pathogenicity. Biofilm formation was assessed using stainless steel AISI 304 #4 slides immersed into brain heart infusion broth, reconstituted powder milk and E. coli preconditioned medium at 25 °C. Our results indicated that a higher amount of biofilm was formed by the wild type strain of L. monocytogenes than by its isogenic mutant, indicating that prfA and sigB are important for biofilm development, especially maturation under our experimental conditions. The presence of E. coli or its metabolites in preconditioned medium did not influence biofilm formation by L. monocytogenes. Our results confirm the possibility of concomitant biofilm formation by L. monocytogenes and E. coli, two bacteria of major significance in the food industry.

Evaluation of treatment outcome after impacted mandibular third molar surgery with the use of autologous platelet-rich fibrin: a randomized controlled clinical study.

PubMed

Kumar, Nilima; Prasad, Kavitha; Ramanujam, Laitha; K, Ranganath; Dexith, Jayashree; Chauhan, Abhishek

2015-06-01

To assess the effect of platelet-rich fibrin (PRF) on postoperative pain, swelling, trismus, periodontal healing on the distal aspect of the second molar, and progress of bone regeneration in mandibular third molar extraction sockets. Over a 2-year period, 31 patients (mean age, 26.1 yr) who required surgical extraction of a single impacted third molar and met the inclusion criteria were recruited. After surgical extraction of the third molar, only primary closure was performed in the control group, whereas PRF was placed in the socket followed by primary closure in the case group (16 patients). The outcome variables were pain, swelling, maximum mouth opening, periodontal pocket depth, and bone formation, with a follow-up period of 3 months. Quantitative data are presented as mean. Statistical significance was inferred at a P value less than .05. Pain (P = .017), swelling (P = .022), and interincisal distance (P = .040) were less in the case group compared with the control group on the first postoperative day. Periodontal pocket depth decreased at 3 months postoperatively in the case (P < .001) and control (P = .014) groups, and this decrease was statistically significant. Bone density scores at 3 months postoperatively were higher in the case group than in the control group, but this difference was not statistically important. The application of PRF lessens the severity of immediate postoperative sequelae, decreases preoperative pocket depth, and hastens bone formation. Copyright © 2015 American Association of Oral and Maxillofacial Surgeons. Published by Elsevier Inc. All rights reserved.

Loss of echogenicity and onset of cavitation from echogenic liposomes: pulse repetition frequency independence

PubMed Central

Radhakrishnan, Kirthi; Haworth, Kevin J; Peng, Tao; McPherson, David D.; Holland, Christy K.

2014-01-01

Echogenic liposomes (ELIP) are being developed for the early detection and treatment of atherosclerotic lesions. An 80% loss of echogenicity of ELIP (Radhakrishnan et al. 2013) has been shown to be concomitant with the onset of stable and inertial cavitation. The ultrasound pressure amplitude at which this occurs is weakly dependent on pulse duration. Smith et al. (2007) have reported that the rapid fragmentation threshold of ELIP (based on changes in echogenicity) is dependent on the insonation pulse repetition frequency (PRF). The current study evaluates the relationship between loss of echogenicity and cavitation emissions from ELIP insonified by duplex Doppler pulses at four PRFs (1.25 kHz, 2.5 kHz, 5 kHz, and 8.33 kHz). Loss of echogenicity was evaluated on B-mode images of ELIP. Cavitation emissions from ELIP were recorded passively on a focused single-element transducer and a linear array. Emissions recorded by the linear array were beamformed and the spatial widths of stable and inertial cavitation emissions were compared to the calibrated azimuthal beamwidth of the Doppler pulse exceeding the stable and inertial cavitation thresholds. The inertial cavitation thresholds had a very weak dependence on PRF and stable cavitation thresholds were independent of PRF. The spatial widths of the cavitation emissions recorded by the passive cavitation imaging system agreed with the calibrated Doppler beamwidths. The results also show that 64%–79% loss of echogenicity can be used to classify the presence or absence of cavitation emissions with greater than 80% accuracy. PMID:25438849

Loss of echogenicity and onset of cavitation from echogenic liposomes: pulse repetition frequency independence.

PubMed

Radhakrishnan, Kirthi; Haworth, Kevin J; Peng, Tao; McPherson, David D; Holland, Christy K

2015-01-01

Echogenic liposomes (ELIP) are being developed for the early detection and treatment of atherosclerotic lesions. An 80% loss of echogenicity of ELIP has been found to be concomitant with the onset of stable and inertial cavitation. The ultrasound pressure amplitude at which this occurs is weakly dependent on pulse duration. It has been reported that the rapid fragmentation threshold of ELIP (based on changes in echogenicity) is dependent on the insonation pulse repetition frequency (PRF). The study described here evaluates the relationship between loss of echogenicity and cavitation emissions from ELIP insonified by duplex Doppler pulses at four PRFs (1.25, 2.5, 5 and 8.33 kHz). Loss of echogenicity was evaluated on B-mode images of ELIP. Cavitation emissions from ELIP were recorded passively on a focused single-element transducer and a linear array. Emissions recorded by the linear array were beamformed, and the spatial widths of stable and inertial cavitation emissions were compared with the calibrated azimuthal beamwidth of the Doppler pulse exceeding the stable and inertial cavitation thresholds. The inertial cavitation thresholds had a very weak dependence on PRF, and stable cavitation thresholds were independent of PRF. The spatial widths of the cavitation emissions recorded by the passive cavitation imaging system agreed with the calibrated Doppler beamwidths. The results also indicate that 64%-79% loss of echogenicity can be used to classify the presence or absence of cavitation emissions with greater than 80% accuracy. Copyright © 2015 World Federation for Ultrasound in Medicine & Biology. Published by Elsevier Inc. All rights reserved.

Clinical evaluation and comparison of the efficacy of coronally advanced flap alone and in combination with platelet rich fibrin membrane in the treatment of Miller Class I and II gingival recessions

PubMed Central

Gupta, Santosh; Banthia, Ruchi; Singh, Pallavi; Banthia, Priyank; Raje, Sapna; Aggarwal, Neha

2015-01-01

Background: The aim of this study was to compare the clinical efficacy of coronally advanced flap (CAF) alone and in combination with autologous platelet rich fibrin membrane (PRF) in Miller's class I and II gingival recessions. Materials and Method: Thirty isolated Miller class I or II sites in 26 subjects were randomly divided into test (15 sites- CAF+PRF) and control (15 sites- CAF alone). Parameters probing pocket depth (PPD), Recession depth (RD), Clinical attachment loss (CAL), Keratinised tissue width (KTW) and Gingival tissue thickness (GTH) were evaluated at baseline, 3 months and 6 months postoperatively. Data was subjected to statistical analysis. P< 0.05 was considered statistically significant. Results: Mean percentage root coverage was 91.00±19.98% and 86.60±23.83% for test and control group respectively. Difference between the groups in all parameters at baseline, 3 months and 6 months was non significant. Complete root coverage was obtained in 12 (80%) and 11 (73.3%) subjects in test and control group respectively. The difference was found to be non-significant. Both groups showed significant differences in all parameters at 3 and 6 months respectively except difference in gingival tissue thickness which was non-significant in control group at 3 months. Conclusion: Combination of PRF to CAF procedure did not provide any added advantage in term of recession coverage in Miller class I and II recessions. Long term trials with more sample size are needed to validate these findings. PMID:26097347

In Flight Evaluation of Active Inceptor Force-Feel Characteristics and Handling Qualities

NASA Technical Reports Server (NTRS)

Lusardi, Jeff A.; Blanken, Chris L.; Ott, Carl Raymond; Malpica, Carlos A.; von Gruenhagen, Wolfgang

2012-01-01

The effect of inceptor feel-system characteristics on piloted handling qualities has been a research topic of interest for many years. Most of the research efforts have focused on advanced fly-by-wire fixed-wing aircraft with only a few studies investigating the effects on rotorcraft. Consequently, only limited guidance is available on how cyclic force-feel characteristics should be set to obtain optimal handling qualities for rotorcraft. To study this effect, the U.S. Army Aeroflightdynamics Directorate working with the DLR Institute of Flight Systems in Germany under Task X of the U.S. German Memorandum of Understanding have been conducting flight test evaluations. In the U.S., five experimental test pilots have completed evaluations of two Mission Task Elements (MTEs) from ADS-33E-PRF and two command/response types for a matrix of center-stick cyclic force-feel characteristics at Moffett Field. In Germany, three experimental test Pilots have conducted initial evaluations of the two MTEs with two command/response types for a parallel matrix of side-stick cyclic force-feel characteristics at WTD-61 in Manching. The resulting data set is used to correlate the effect of changes in natural frequency and damping ratio of the cyclic inceptor on the piloted handling qualities. Existing criteria in ADS-33E and a proposed Handling Qualities Sensitivity Function that includes the effects of the cyclic force-feel characteristics are also evaluated against the data set and discussed.

Fpga based L-band pulse doppler radar design and implementation

NASA Astrophysics Data System (ADS)

Savci, Kubilay

As its name implies RADAR (Radio Detection and Ranging) is an electromagnetic sensor used for detection and locating targets from their return signals. Radar systems propagate electromagnetic energy, from the antenna which is in part intercepted by an object. Objects reradiate a portion of energy which is captured by the radar receiver. The received signal is then processed for information extraction. Radar systems are widely used for surveillance, air security, navigation, weather hazard detection, as well as remote sensing applications. In this work, an FPGA based L-band Pulse Doppler radar prototype, which is used for target detection, localization and velocity calculation has been built and a general-purpose Pulse Doppler radar processor has been developed. This radar is a ground based stationary monopulse radar, which transmits a short pulse with a certain pulse repetition frequency (PRF). Return signals from the target are processed and information about their location and velocity is extracted. Discrete components are used for the transmitter and receiver chain. The hardware solution is based on Xilinx Virtex-6 ML605 FPGA board, responsible for the control of the radar system and the digital signal processing of the received signal, which involves Constant False Alarm Rate (CFAR) detection and Pulse Doppler processing. The algorithm is implemented in MATLAB/SIMULINK using the Xilinx System Generator for DSP tool. The field programmable gate arrays (FPGA) implementation of the radar system provides the flexibility of changing parameters such as the PRF and pulse length therefore it can be used with different radar configurations as well. A VHDL design has been developed for 1Gbit Ethernet connection to transfer digitized return signal and detection results to PC. An A-Scope software has been developed with C# programming language to display time domain radar signals and detection results on PC. Data are processed both in FPGA chip and on PC. FPGA uses fixed point arithmetic operations as it is fast and facilitates source requirement as it consumes less hardware than floating point arithmetic operations. The software uses floating point arithmetic operations, which ensure precision in processing at the expense of speed. The functionality of the radar system has been tested for experimental validation in the field with a moving car and the validation of submodules are tested with synthetic data simulated on MATLAB.

Interpretation of open system petrogenetic processes: Phase equilibria constraints on magma evolution

NASA Astrophysics Data System (ADS)

Defant, Marc J.; Nielsen, Roger L.

1990-01-01

We have used a computer model (TRACES) to simulate low pressure differentiation of natural basaltic magmas in an attempt to investigate the chemical dynamics of open system magmatic processes. Our results, in the form of simulated liquid lines of descent and the calculated equilibrium mineralogy, were determined for perfect fractional crystallization; fractionation paired with recharge and eruption (PRF); fractionation paired with assimilation (AFC); and fractionation paired with recharge, eruption, and assimilation (FEAR). These simulations were calculated in an attempt to assess the effects of combinations of petrogenetic processes on major and trace element evolution of natural systems and to test techniques that have been used to decipher the relative roles of these processes. If the results of PRF calculations are interpreted in terms of a mass balance based fractionation model (e.g., Bryan et al., 1969), it is possible to generate low residuals even if one assumes that fractional crystallization was the only active process. In effect, the chemical consequences of recharge are invisible to mass balance models. Pearce element ratio analyses, however, can effectively discern the effects of PRF versus simple fractionation. The fractionating mineral proportions, and therefore, bulk distribution coefficients ( D¯) of a differentiating system are dependent on the recharge or assimilation rate. Comparison of the results of simulations assuming constant D¯ with the results calculated by TRACES show that the steady state liquid concentrations of some elements can differ by a factor of 2 to 5. If the PRF simulation is periodic, with episodes of mixing separated by intervals of fractionation, parallel liquidus mineral control lines are produced. Most of these control lines do not project back to the parental composition. This must be an important consideration when attempting to calculate a potential parental magma for any natural suite where magma chamber recharge has occurred. Most basaltic magmas cannot evolve to high silica compositions without magnetite fractionation. Small amounts of rhyolite assimilation (assimilation/fractionation < 0.1), however, can drive evolving basalts to more silica rich compositions. If mass balance models are used to interpret these synthetic AFC data, low residuals are obtained if magnetite is added to the crystallizing assemblage. This approach works even for cases where magnetite was not a fractionating phase. Thus, the mass balance results are mathematically correct, but are geologically irrelevant.

High efficiency stratification of apple cultivar Ligol seed dormancy by phytohormones, heat shock and pulsed radio frequency.

PubMed

Grzesik, Mieczysław; Górnik, Krzysztof; Janas, Regina; Lewandowki, Mariusz; Romanowska-Duda, Zdzislawa; Duijn, Bert van

2017-12-01

The aim of the study was to improve the effect of stratification of apple "Ligol" seeds by application of selected compounds, phytohormones, and physical methods For this purpose the seeds were stratified at 3°C in distilled water or in the presence of potassium nitrate (KNO 3 ), ethephon (ET), carbon monoxide (CO), hydrogen peroxide (H 2 O 2 ), a mixture of KNO 3 , ET, CO, H 2 O 2 , gibberellins (GA 3 ), 6-benzylaminopurine (BAP), jasmonic acid (JA), salicylic acid (SA) and a mixture of SA, GA 3 , BAP, JA, nitric oxide (NO), hydrogen chloride (HCL). Arranged protocols included various durations and combinations of selected compounds and phytohormones as well as laser and red light, heat shock - 2h heat shock (45°C) and Pulsed Radio Frequency (PRF) were investigated by germination tests and the activity of selected enzymes, gas exchange and index of chlorophyll in leaves. The obtained results showed the possibility to shorten more effectively the time of the apple 'Ligol' dormancy removal by treatments of the stratified seeds at 3°C with different biological and physical methods Selected compounds and phytohormones acted collectively as a regulatory complex controlling the course of release from dormancy. Physical methods (PRF and heat shock) additionally contributed to dormancy breakage. Duration of phytohormones or compounds impacts during stratification should be prolonged to minimum 7days to assure more balanced conditions of the regulatory complex for the acceleration of dormancy a removal. The most beneficial results were obtained after seed stratification for 7days on filter paper moistened in KNO 3 +Etephon+CO+H 2 O 2 at 3°C, and then on filter paper moistened in phytohormones (GA 3 +BAP+JA) till the end of seed germination (3°C). The application of this protocol could be a very useful tool in a shortening the apple breeding cycle since the period of removing dormancy was reduced by 38days in comparison to stratified in water. PRF has also the additive role in breaking dormancy of apple 'Ligol' seed. Positive effects of compounds and phytohormones applied during stratification remarkably accelerated the growth of developed from them seedlings. Further research is needed to optimize stratification methods with appropriate contents and concentrations of compounds and phytohormones combined with PRF exposure. Copyright © 2017 Elsevier GmbH. All rights reserved.

Comparison between whole-body and head and neck neurovascular coils for 3-T magnetic resonance proton resonance frequency shift thermography guidance in the head and neck region.

PubMed

Ginat, Daniel Thomas; Anthony, Gregory J; Christoforidis, Gregory; Oto, Aytekin; Dalag, Leonard; Sammet, Steffen

2018-02-01

The purpose of this study is to compare the image quality of magnetic resonance (MR) treatment planning images and proton resonance frequency (PRF) shift thermography images and inform coil selection for MR-guided laser ablation of tumors in the head and neck region. Laser ablation was performed on an agar phantom and monitored via MR PRF shift thermography on a 3-T scanner, following acquisition of T1-weighted (T1W) planning images. PRF shift thermography images and T2-weighted (T2W) planning images were also performed in the neck region of five normal human volunteers. Signal-to-noise ratios (SNR) and temperature uncertainty were calculated and compared between scans acquired with the quadrature mode body integrated coil and a head and neck neurovascular coil. T1W planning images of the agar phantom produced SNRs of 4.0 and 12.2 for the quadrature mode body integrated coil and head and neck neurovascular coil, respectively. The SNR of the phantom MR thermography magnitude images obtained using the quadrature mode body integrated coil was 14.4 versus 59.6 using the head and neck coil. The average temperature uncertainty for MR thermography performed on the phantom with the quadrature mode body integrated coil was 1.1 versus 0.3 °C with the head and neck coil. T2W planning images of the neck in five human volunteers produced SNRs of 28.3 and 91.0 for the quadrature mode body integrated coil and head and neck coil, respectively. MR thermography magnitude images of the neck in the volunteers obtained using the quadrature mode body integrated coil had a signal-to-noise ratio of 8.3, while the SNR using the head and neck coil was 16.1. The average temperature uncertainty for MR thermography performed on the volunteers with the body coil was 2.5 versus 1.6 °C with the head and neck neurovascular coil. The quadrature mode body integrated coil provides inferior image quality for both basic treatment planning sequences and MR PRF shift thermography compared with a neurovascular coil, but may nevertheless be adequate for clinical purposes.

Using the Kepler Full Frame Images to Find Long-Period Variables in the Milky Way

NASA Astrophysics Data System (ADS)

Mullen, Melissa A.; Kraemer, Kathleen; Kuchar, T. A.; Sloan, G. C.

2018-01-01

We are using the monthly Full Frame Images (FFIs) images from the 4+ year Kepler mission to conduct a uniform census of long-period variables (LPVs, primarily Miras and semiregular variables) in the Milky Way disk. Our goal is to help understand how stellar pulsation and dust production interact as these dying stars eject their envelopes and enrich the interstellar medium with new fusion products and dust. To that end, we are processing the monthly FFIs for the entire 116 square-degree Kepler field to identify the LPVs and determine their period, pulsation mode, and amplitude measured with the same instrument for the 4+ year mission. Since the FFIs are not fully calibrated, we must first remove the instrumental systematics from the data and determine the flux calibration factors that can then be applied to all the stars in the field. To find these corrections, we use aperture photometry and PRF-fitting from well-characterized stars known to be stable – those with exoplanet candidates. We remove effects of the quarterly spacecraft rolls as well as longterm trends in the responsivity, which reduces the scatter in each star from 5-10% to <1-3%. We examine the effects of the optical distortions that are present in the outer parts of the array, as well as source crowding throughout the field. The fluxes from the PRF fits are typically ~1% higher than those from the aperture photometry. We present preliminary results on previously known and new, candidate, variable stars in a test field near the center of the FFIs.This work is supported by NASA ADAP grant NNX16AF45G.

Visual Field Map Clusters in High-Order Visual Processing: Organization of V3A/V3B and a New Cloverleaf Cluster in the Posterior Superior Temporal Sulcus

PubMed Central

Barton, Brian; Brewer, Alyssa A.

2017-01-01

The cortical hierarchy of the human visual system has been shown to be organized around retinal spatial coordinates throughout much of low- and mid-level visual processing. These regions contain visual field maps (VFMs) that each follows the organization of the retina, with neighboring aspects of the visual field processed in neighboring cortical locations. On a larger, macrostructural scale, groups of such sensory cortical field maps (CFMs) in both the visual and auditory systems are organized into roughly circular cloverleaf clusters. CFMs within clusters tend to share properties such as receptive field distribution, cortical magnification, and processing specialization. Here we use fMRI and population receptive field (pRF) modeling to investigate the extent of VFM and cluster organization with an examination of higher-level visual processing in temporal cortex and compare these measurements to mid-level visual processing in dorsal occipital cortex. In human temporal cortex, the posterior superior temporal sulcus (pSTS) has been implicated in various neuroimaging studies as subserving higher-order vision, including face processing, biological motion perception, and multimodal audiovisual integration. In human dorsal occipital cortex, the transverse occipital sulcus (TOS) contains the V3A/B cluster, which comprises two VFMs subserving mid-level motion perception and visuospatial attention. For the first time, we present the organization of VFMs in pSTS in a cloverleaf cluster. This pSTS cluster contains four VFMs bilaterally: pSTS-1:4. We characterize these pSTS VFMs as relatively small at ∼125 mm2 with relatively large pRF sizes of ∼2–8° of visual angle across the central 10° of the visual field. V3A and V3B are ∼230 mm2 in surface area, with pRF sizes here similarly ∼1–8° of visual angle across the same region. In addition, cortical magnification measurements show that a larger extent of the pSTS VFM surface areas are devoted to the peripheral visual field than those in the V3A/B cluster. Reliability measurements of VFMs in pSTS and V3A/B reveal that these cloverleaf clusters are remarkably consistent and functionally differentiable. Our findings add to the growing number of measurements of widespread sensory CFMs organized into cloverleaf clusters, indicating that CFMs and cloverleaf clusters may both be fundamental organizing principles in cortical sensory processing. PMID:28293182

A novel SMAC mimetic APG-1387 exhibits dual antitumor effect on HBV-positive hepatocellular carcinoma with high expression of cIAP2 by inducing apoptosis and enhancing innate anti-tumor immunity.

PubMed

Pan, Wentao; Luo, Qiuyun; Yan, Xianglei; Yuan, Luping; Yi, Hanjie; Zhang, Lin; Li, Baoxia; Zhang, Yuxin; Sun, Jian; Qiu, Miao-Zhen; Yang, Da-Jun

2018-04-18

Check point inhibitor anti-PD1 antibody produced some efficacy in Hepatocellular Carcinoma (HCC) patients previously treated with sorafenib. Unfortunately, HCC patients with hepatitis B virus (HBV) infection did not respond as well as uninfected patients. Previously, Second mitochondria-derived activator of caspases (SMAC) mimetics-the antagonist for inhibitor of apoptosis proteins (IAPs) can rapidly reduce serum hepatitis B virus DNA in animal model. APG-1387 is a novel SMAC-mimetic, small molecule inhibitor targeting inhibitor of apoptosis proteins (IAPs). In our study, firstly, we found that HCC patients with copy number alteration of cIAP1, cIAP2, and XIAP had a dismal prognosis. Then, we discovered that APG-1387 alone could induce apoptosis of PLC/PRF/5 which was HBV positive both in-vitro and in-vivo. Furthermore, we found that APG-1387 significantly up-regulated the expression of calreticulin and HLA-DR in PLC/PRF/5 via activating non-classic NF-κB pathway. Also, compared to vehicle group, APG-1387 increased NK cell counts by 5 folds in PLC/PRF/5 xenograft model. In-vitro, APG-1387 positively regulated T cells by reducing Treg differentiation and down-regulating PD1 expression in CD4 T cell. Moreover, APG-1387 had no impact on memory T cells. Consequently, our results suggest that APG1387 could be a good candidate to combine with anti-PD1 antibody treatment to overcome low responds of check point inhibitors in HBV positive HCC. Copyright © 2018 Elsevier Inc. All rights reserved.

Authentication of meat products: determination of animal feeding by parallel GC-MS analysis of three adipose tissues.

PubMed

Sivadier, Guilhem; Ratel, Jérémy; Bouvier, Frédéric; Engel, Erwan

2008-11-12

Authentication of farm animal rearing conditions, especially the type of feeding, is a key issue in certification of meat quality and meat products. The purpose of this article was to analyze in parallel the volatile fraction of three adipose tissues excised from 16 lambs in order to authenticate two animal diets: pasture (n = 8) and concentrate (n = 8). On the basis of growth rate and anatomical location, three different lamb adipose tissues were analyzed: perirenal fat (PRF), caudal subcutaneous fat (CSCF), and heart fat (HF). An initial experiment was used to optimize the extraction of volatile compounds from the adipose tissues. Using a lipid liquid phase extraction, heating the ground tissue to 70 degrees C, was shown to be the best sample preparation mode before dynamic headspace-gas chromatography-mass spectrometry (DH-GC-MS) analysis to achieve a good representation of the starting material, while getting a good extraction and reproducibility. Next, the application of an instrumental drifts correction procedure to DH-GC-MS data enabled the identification of 130 volatile compounds that discriminate the two diets in one or several of the three tissues: 104 were found in PRF, 75 in CSCF, and 70 in HF. Forty-eight of these diet tracers, including 2,3-octanedione, toluene, terpenes, alkanes, alkenes, and ketones, had previously been identified as ruminant pasture-diet tracers and can be considered generic of this type of animal feeding. Moreover, 49 of the 130 compounds could identify diets in only one tissue, suggesting that complementary analysis of several tissues is superior for diet identification. Finally, multivariate discriminant analyses confirmed that the discrimination was improved when PRF, CSCF, and HF were considered simultaneously, even if HF contributed minimal information.

ALART: a novel lidar system for vegetation height retrieval from space

NASA Astrophysics Data System (ADS)

Foglia Manzillo, P.; van Dijk, C. N.; Conticello, S.; Esposito, M.; Lussana, R.; Villa, F.; Tamborini, D.; Zappa, F.; Tosi, A.; Roncat, A.; Pfeiffer, N.; Entner, T.; Lampridis, D.

2015-10-01

We propose a multi-kHz Single-Photon Counting (SPC) space LIDAR, exploiting low energy pulses with high repetition frequency (PRF). The high PRF allows one to overcome the low signal limitations, as many return shots can be collected from nearly the same scattering area. The ALART space instrument exhibits a multi-beam design, providing height retrieval over a wide area and terrain slope measurements. This novel technique, working with low SNRs, allows multiple beam generation with a single laser, limiting mass and power consumption. As the receiver has a certain probability to detect multiple photons from different levels of canopy, a histogram is constructed and used to retrieve the properties of the target tree, by means of a modal decomposition of the reconstructed waveform. A field demonstrator of the ALART space instrument is currently being developed by a European consortium led by cosine | measurement systems and funded by ESA under the TRP program. The demonstrator requirements have been derived to be representative of the target instrument and it will be tested in an equipped tower in woodland areas in the Netherlands. The employed detectors are state-of-the-art CMOS Single-Photon Avalanche Diode (SPAD) matrices with 1024 pixels. Each pixel is independently equipped with an integrated Time-to-Digital Converter (TDC), achieving a timing accuracy that is much lower than the SPAD dead time, resulting in a distance resolution in the centimeter range. The instrument emits nanosecond laser pulses with energy on the order of several μJ, at a PRF of ~ 10 kHz, and projects on ground a three-beams pattern. An extensive field measurement campaign will validate the employed technologies and algorithms for vegetation height retrieval.

Role of T-bet, the master regulator of Th1 cells, in the cytotoxicity of murine CD4+ T cells.

PubMed

Eshima, Koji; Misawa, Kana; Ohashi, Chihiro; Iwabuchi, Kazuya

2018-05-01

Although CD4 + T cells are generally regarded as helper T cells, some activated CD4 + T cells have cytotoxic properties. Given that CD4 + cytotoxic T lymphocytes (CTLs) often secrete IFN-γ, CTL activity among CD4 + T cells may be attributable to Th1 cells, where a T-box family molecule, T-bet serves as the "master regulator". However, although the essential contribution of T-bet to expression of IFN-γ has been well-documented, it remains unclear whether T-bet is involved in CD4 + T cell-mediated cytotoxicity. In this study, to investigate the ability of T-bet to confer cytolytic activity on CD4 + T cells, the T-bet gene (Tbx21) was introduced into non-cytocidal CD4 + T cell lines and their cytolytic function analyzed. Up-regulation of FasL (CD178), which provided the transfectant with cytotoxicity, was observed in Tbx21transfected CD4 + T cells but not in untransfected parental cells. In one cell line, T-bet transduction also induced perforin gene (Prf1) expression and Tbx21 transfectants efficiently killed Fas - target cells. Although T-bet was found to repress up-regulation of CD40L (CD154), which controls FasL-mediated cytolysis, the extent of CD40L up-regulation on in vitro-differentiated Th1 cells was similar to that on Th2 cells, suggesting the existence of a compensatory mechanism. These results collectively indicate that T-bet may be involved in the expression of genes, such as FasL and Prf1, which confer cytotoxicity on Th1 cells. © 2018 The Societies and John Wiley & Sons Australia, Ltd.

Treatment of endo-periodontal lesion using leukocyte-platelet-rich fibrin. A case report

PubMed Central

Elgueta, Ricardo; Fuentes, Ramon

2017-01-01

Abstract Case Description: The main objective of this paper was to report the clinical effectiveness of leukocyte- platelet- rich fibrin (L-PRF) in the treatment of a combined endo-periodontal lesion of an upper first premolar. Clinical Findings: The tooth had a profound abfraction on the vestibular aspect and presented no mobility but revealed a deep pocket measuring of 11 mm on the mesial vestibular aspect and 14 mm on the mesial palatine aspect. The three dimensional image analysis showed total bone loss in the mesial aspect and an extensively bone loss of the vestibular aspect of the vestibular root. Treatment and Outcome: Endodontic treatment was performed and periodontal access surgery (surgical periodontal therapy) was done with the application of autologous L-PRF. Three month and 6 months after surgery, the cone beam computed tomography (CBCT) exams showed no bone regeneration in any aspect of the tooth. However, periodontal examination showed a significative improvement in the deepness of surcus. The mesial vestibular aspect had a deep pocket of 3 mm and 5 mm on the mesial palatine aspect showing a reduction in deepness of 8 mm and 9 mm, respectively. Clinical Relevance: The actual treatment for teeth with bad prognosis is the extraction and replacement with implants. Even though implants are capable of restore function and aesthetic, the abuse of this approach have led to the loss of teeth that could be successfully treated with a less invasive technique. The prognosis of teeth with endoperiodontal lesion is poor but could be enhanced with regenerative therapies. Until now there are no clinical trials and just four case report about the treatment of these teeth with platelet rich fibrin. PMID:29662262

STS-134 crew during PDRS PRF ADV (AMS) traiining

NASA Image and Video Library

2011-03-23

JSC2011-E-028158 (23 March 2011) --- NASA astronaut Greg H. Johnson, STS-134 pilot, participates in an exercise in the systems engineering simulator in the Avionics Systems Laboratory at NASA's Johnson Space Center. Photo credit: NASA or National Aeronautics and Space Administration

Low Probability of Intercept Laser Range Finder

DTIC Science & Technology

2017-07-19

time of arrival, and it may also include wavelength, pulse width, and pulse repetition frequency (PRF). Second photodetector 38 in conjunction with... conjunction with lens 32 and telescope 36 that can correct for turbulence along the free space path. [0024] In all embodiments, the time interval

Platelet rich fibrin: a new paradigm in periodontal regeneration.

PubMed

Kumar, R Vinaya; Shubhashini, N

2013-09-01

Among the great challenges facing clinical research is the development of bioactive surgical additives regulating inflammation and increasing healing. Although the use of fibrin adhesives and platelet-rich plasma (PRP) is well documented, they have their own limitations. Hence, reconstructive dental surgeons are looking for an "edge" that jump starts the healing process to maximize predictability as well as the volume of regenerated bone. Overcoming the restrictions related to the reimplantation of blood-derived products, a new family of platelet concentrate, which is neither a fibrin glue nor a classical platelet concentrate, was developed in France. This second generation platelet concentrate called platelet-rich fibrin (PRF), has been widely used to accelerate soft and hard tissue healing. Its advantages over the better known PRP include ease of preparation/application, minimal expense, and lack of biochemical modification (no bovine thrombin or anticoagulant is required). This article serves as an introduction to the PRF "concept" and its potential clinical applications with emphasis on periodontal regeneration.

Combination of diagnostic medial calcaneal nerve block followed by pulsed radiofrequency for plantar fascitis pain: A new modality

PubMed Central

Thapa, Deepak; Ahuja, Vanita

2014-01-01

Plantar fasciitis (PF) is the most common cause of chronic heel pain which may be bilateral in 20 to 30% of patients. It is a very painful and disabling condition which can affect the quality of life. The management includes both pharmacological and operative procedures with no single proven effective treatment modality. In the present case series, we managed three patients with PF (one with bilateral PF). Following a diagnostic medial calcaneal nerve (MCN) block at its origin, we observed reduction in verbal numerical rating scale (VNRS) in all the three patients. Two patients has relapse of PF pain which was managed with MCN block followed with pulsed radio frequency (PRF). All the patients were pain-free at the time of reporting. This case series highlights the possible role of combination of diagnostic MCN block near its origin followed with PRF as a new modality in management of patients with PF. PMID:24963184

ERPs reveal sub-lexical processing in Chinese character recognition.

PubMed

Wu, Yan; Mo, Deyuan; Tsang, Yiu-Kei; Chen, Hsuan-Chih

2012-04-18

The present study used ERPs and a lexical decision task to explore the roles of position-general and position-specific radicals and their relative time courses in processing Chinese characters. Two types of radical frequency were manipulated: the number of characters containing a specific radical irrespective of position (i.e., radical frequency or RF) and the number of characters containing a specific radical at a particular position (i.e., position-specific radical frequency or PRF). The PRF effect was found to be associated with P150, P200, and N400, whereas the RF effect was associated with P200. These results suggest that both position-general and position-specific radicals could influence character processing, but the effect of position-specific radicals appeared earlier and lasted longer than that of position-general radicals. These findings are interpreted in terms of the specific orthographic properties of the sub-lexical components of Chinese characters. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

Construction and comparison of Louisiana's conventional and alternative base courses under accelerated loading : construction report.

DOT National Transportation Integrated Search

1996-11-01

The Louisiana Transportation Research Center's (LTRC) Pavement Research Facility (PRF) is a permanent, outdoor, full-scale testing laboratory located on a six site in Port Allen, Louisiana. The purpose of this facility is to test and quantify full-sc...

CP-31398 inhibits the growth of p53-mutated liver cancer cells in vitro and in vivo.

PubMed

He, Xing-Xing; Zhang, Yu-Nan; Yan, Jun-Wei; Yan, Jing-Jun; Wu, Qian; Song, Yu-Hu

2016-01-01

The tumor suppressor p53 is one of the most frequently mutated genes in hepatocellular carcinoma (HCC). Previous studies demonstrated that CP-31398 restored the native conformation of mutant p53 and trans-activated p53 downstream genes in tumor cells. However, the research on the application of CP-31398 to liver cancer has not been reported. Here, we investigated the effects of CP-31398 on the phenotype of HCC cells carrying p53 mutation. The effects of CP-31398 on the characteristic of p53-mutated HCC cells were evaluated through analyzing cell cycle, cell apoptosis, cell proliferation, and the expression of p53 downstream genes. In tumor xenografts developed by PLC/PRF/5 cells, the inhibition of tumor growth by CP-31398 was analyzed through gross morphology, growth curve, and the expression of p53-related genes. Firstly, we demonstrated that CP-31398 inhibited the growth of p53-mutated liver cancer cells in a dose-dependent and p53-dependent manner. Then, further study showed that CP-31398 re-activated wild-type p53 function in p53-mutated HCC cells, which resulted in inhibitive response of cell proliferation and an induction of cell-cycle arrest and apoptosis. Finally, in vivo data confirmed that CP-31398 blocked the growth of xenografts tumors through transactivation of p53-responsive downstream molecules. Our results demonstrated that CP-31398 induced desired phenotypic change of p53-mutated HCC cells in vitro and in vivo, which revealed that CP-31398 would be developed as a therapeutic candidate for HCC carrying p53 mutation.

Structure of the Upper Mantle and Mantle Transition Zone in Central Mongolia

NASA Astrophysics Data System (ADS)

Cui, Z.; Meltzer, A.; Stachnik, J.; Fischer, K. M.; Russo, R. M.; Munkhuu, U.; Baasanbat, T.

2016-12-01

Located between two major Archean cratons, the Siberian Craton to the north and the Tarim and Sino-Korean Cratons to the south, the lithosphere of Central Mongolia was constructed over an extended period of orogenesis associated with the Central Asian Orogenic Belt. Archean to Early Proterozoic basement was modified by accreted subduction complexes during the Paleozoic and early Mesozoic and basalt magmatism in the Cenozoic. Central and western Mongolia constitute a significant portion of the greater Mongolian plateau, an approximately 2.6 million km2area of Central Asia with an average elevation of 1500 meters. The high topography of the Mongolian Plateau has been attributed to far-field effects of India-Asia convergence, Pacific plate subduction, mantle plume activity, convective mantle flow, and magmatic underplating. The origin and persistence of continental plateaus through time provides insight into the evolution of continents and interactions between mantle dynamics and surface processes. As part of a larger interdisciplinary project to understand the origin of high topography in continental interiors we deployed 112 seismic broadband stations in central Mongolia as three separate subarrays in two separate mobilizations over a four year period (2012-2016). The stations extend from the Hovsgol rift in northern Mongolia, through the Hangay Dome, and into the Gobi Altai in southern Mongolia. We use S wave Receiver functions (SRF) to examine the lithosphere asthenosphere boundary and P wave Receiver functions (PRF) to investigate the mantle transition zone (MTZ). Preliminary SRF results from the subarray in the Hangay show lithospheric thinning and E-W variation. The LAB beneath the Hangay is 100km. It gradually thins to 90 km at the western end of the central Hangay and thins more abruptly to 80km at the eastern end of the central Hangay. These results are in agreement with results from joint inversion of receiver functions and surface waves and teleseismic tomography. PRF exhibit a clear Ps arrival from the 410-km discontinuity but a weak Ps phase converted from 660-km discontinuity in both station and CCP stacks. The 410-km Ps arrival is gradually delayed from south to north corresponding to a depth change of 20km. Several stations with visible 660-km Ps suggest a 10-30 km thinning within the MTZ.

ICESat-2 laser technology development

NASA Astrophysics Data System (ADS)

Edwards, Ryan; Sawruk, Nick W.; Hovis, Floyd E.; Burns, Patrick; Wysocki, Theodore; Rudd, Joe; Walters, Brooke; Fakhoury, Elias; Prisciandaro, Vincent

2013-09-01

A number of ICESat-2 system requirements drove the technology evolution and the system architecture for the laser transmitter Fibertek has developed for the mission.. These requirements include the laser wall plug efficiency, laser reliability, high PRF (10kHz), short-pulse (<1.5ns), relatively narrow spectral line-width, and wave length tunability. In response to these requirements Fibertek developed a frequency-doubled, master oscillator/power amplifier (MOPA) laser that incorporates direct pumped diode pumped Nd:YVO4 as the gain media, Another guiding force in the system design has been extensive hardware life testing that Fibertek has completed. This ongoing hardware testing and development evolved the system from the original baseline brass board design to the more robust flight laser system. The final design meets or exceeds all NASA requirements and is scalable to support future mission requirements.

Effect of laser parameters on surface roughness of laser modified tool steel after thermal cyclic loading

NASA Astrophysics Data System (ADS)

Lau Sheng, Annie; Ismail, Izwan; Nur Aqida, Syarifah

2018-03-01

This study presents the effects of laser parameters on the surface roughness of laser modified tool steel after thermal cyclic loading. Pulse mode Nd:YAG laser was used to perform the laser surface modification process on AISI H13 tool steel samples. Samples were then treated with thermal cyclic loading experiments which involved alternate immersion in molten aluminium (800°C) and water (27°C) for 553 cycles. A full factorial design of experiment (DOE) was developed to perform the investigation. Factors for the DOE are the laser parameter namely overlap rate (η), pulse repetition frequency (f PRF) and peak power (Ppeak ) while the response is the surface roughness after thermal cyclic loading. Results indicate the surface roughness of the laser modified surface after thermal cyclic loading is significantly affected by laser parameter settings.

STS-134 crew during PDRS PRF ADV (AMS) traiining

NASA Image and Video Library

2011-03-23

JSC2011-E-028160 (23 March 2011) --- NASA astronauts Greg H. Johnson (right), STS-134 pilot; and Greg Chamitoff, mission specialist, are pictured during an exercise in the systems engineering simulator in the Avionics Systems Laboratory at NASA's Johnson Space Center. Photo credit: NASA or National Aeronautics and Space Administration

The "U.S. Monthly Catalog" and the "Publications Reference File" as Collection Development Tools.

ERIC Educational Resources Information Center

Reno, Ramona L.

1994-01-01

Reports on an analysis of the availability of publications contained in the 1991 "Monthly Catalog of United States Government Publications" through depository libraries, the Government Printing Office (GPO) Sales Program and its Publications Reference File (PRF), and federal agency distribution centers. Implications for collection…

Survival of the Partial Reinforcement Extinction Effect after Contextual Shifts

ERIC Educational Resources Information Center

Boughner, Robert L.; Papini, Mauricio R.

2006-01-01

The effects of contextual shifts on the partial reinforcement extinction effect (PREE) were studied in autoshaping with rats. Experiment 1 established that the two contexts used subsequently were easily discriminable and equally salient. In Experiment 2, independent groups of rats received acquisition training under partial reinforcement (PRF) or…

ASXL gain-of-function truncation mutants: defective and dysregulated forms of a natural ribosomal frameshifting product?

PubMed

Dinan, Adam M; Atkins, John F; Firth, Andrew E

2017-10-16

Programmed ribosomal frameshifting (PRF) is a gene expression mechanism which enables the translation of two N-terminally coincident, C-terminally distinct protein products from a single mRNA. Many viruses utilize PRF to control or regulate gene expression, but very few phylogenetically conserved examples are known in vertebrate genes. Additional sex combs-like (ASXL) genes 1 and 2 encode important epigenetic and transcriptional regulatory proteins that control the expression of homeotic genes during key developmental stages. Here we describe an ~150-codon overlapping ORF (termed TF) in ASXL1 and ASXL2 that, with few exceptions, is conserved throughout vertebrates. Conservation of the TF ORF, strong suppression of synonymous site variation in the overlap region, and the completely conserved presence of an EH[N/S]Y motif (a known binding site for Host Cell Factor-1, HCF-1, an epigenetic regulatory factor), all indicate that TF is a protein-coding sequence. A highly conserved UCC_UUU_CGU sequence (identical to the known site of +1 ribosomal frameshifting for influenza virus PA-X expression) occurs at the 5' end of the region of enhanced synonymous site conservation in ASXL1. Similarly, a highly conserved RG_GUC_UCU sequence (identical to a known site of -2 ribosomal frameshifting for arterivirus nsp2TF expression) occurs at the 5' end of the region of enhanced synonymous site conservation in ASXL2. Due to a lack of appropriate splice forms, or initiation sites, the most plausible mechanism for translation of the ASXL1 and 2 TF regions is ribosomal frameshifting, resulting in a transframe fusion of the N-terminal half of ASXL1 or 2 to the TF product, termed ASXL-TF. Truncation or frameshift mutants of ASXL are linked to myeloid malignancies and genetic diseases, such as Bohring-Opitz syndrome, likely at least in part as a result of gain-of-function or dominant-negative effects. Our hypothesis now indicates that these disease-associated mutant forms represent overexpressed defective versions of ASXL-TF. This article was reviewed by Laurence Hurst and Eugene Koonin.

Pulse Circuits of Radar Stations

DTIC Science & Technology

1982-08-06

be less than in a symmetrical flip-flop since voltage webs additionally is reduced, given presence of cathode coupling (triode L2 cathode potential...and t, f(t). 636 7o%:i. iI where C’ - d-c component equal, in accordance with (1.5) -- L. ( * -. wiX " -- angular pulse repetition frequency tPRF]; T. K

High temperature performance of soy-based adhesives

Treesearch

Jane L. O’Dell; Christopher G. Hunt; Charles R. Frihart

2013-01-01

We studied the high temperature performance of soy meal processed to different protein concentrations (flour, concentrate, and isolate), as well as formulated soy-based adhesives, and commercial nonsoy adhesives for comparison. No thermal transitions were seen in phenol-resorcinol-formaldehyde (PRF) or soy-phenol-formaldehyde (SoyPF) or in as-received soy flour...

Differential expression of immune-regulatory genes associated with PD-L1 display in melanoma: implications for PD-1 pathway blockade

PubMed Central

Taube, Janis M.; Young, Geoffrey D.; McMiller, Tracee L.; Chen, Shuming; Salas, January T.; Pritchard, Theresa S.; Xu, Haiying; Meeker, Alan K.; Fan, Jinshui; Cheadle, Chris; Berger, Alan E.; Pardoll, Drew M.; Topalian, Suzanne L.

2015-01-01

Purpose Blocking the immunosuppressive PD-1/PD-L1 pathway has anti-tumor activity in multiple cancer types, and PD-L1 expression on tumor cells and infiltrating myeloid cells correlates with the likelihood of response. We previously found that IFNG (interferon-gamma) was over-expressed by TILs in PD-L1+ vs. PD-L1(−) melanomas, creating adaptive immune resistance by promoting PD-L1 display. The current study was undertaken to identify additional factors in the PD-L1+ melanoma microenvironment coordinately contributing to immunosuppression. Experimental design Archived, formalin-fixed paraffin-embedded melanoma specimens were assessed for PD-L1 protein expression at the tumor cell surface with immunohistochemistry (IHC). Whole genome expression analysis, quantitative (q)RT-PCR, immunohistochemistry, and functional in vitro validation studies were employed to assess factors differentially expressed in PD-L1+ versus PD-L1(−) melanomas. Results Functional annotation clustering based on whole genome expression profiling revealed pathways up-regulated in PD-L1+ melanomas, involving immune cell activation, inflammation, and antigen processing and presentation. Analysis by qRT-PCR demonstrated over-expression of functionally related genes in PD-L1+ melanomas, involved in CD8+ T cell activation (CD8A, IFNG, PRF1, CCL5), antigen presentation (CD163, TLR3, CXCL1, LYZ), and immunosuppression [PDCD1 (PD-1), CD274(PD-L1), LAG3, IL10]. Functional studies demonstrated that some factors, including IL-10 and IL-32-gamma, induced PD-L1 expression on monocytes but not tumor cells. Conclusions These studies elucidate the complexity of immune checkpoint regulation in the tumor microenvironment, identifying multiple factors likely contributing to coordinated immunosuppression. These factors may provide tumor escape mechanisms from anti-PD-1/PD-L1 therapy, and should be considered for co-targeting in combinatorial immunomodulation treatment strategies. PMID:25944800

Compact and efficient 2μm Tm:YAP lasers with mechanical or passive Q-switching

NASA Astrophysics Data System (ADS)

Cole, Brian; Goldberg, Lew

2017-02-01

We describe compact and efficient Q-switched diode-pumped, Tm:YAP lasers operating at 1.94μm. Laser CW and Q-switched performance is compared, using both compact mechanical as well as passive Q-switching. For passive Q-switching using a Cr:ZnS saturable absorber (unsaturated transmission of 95%), the laser produced 0.5mJ pulses with an average power of 4.4W and 6.5kW peak power, and had an optical efficiency of 30%. A resonant mirror mechanical Q-switch resulted in a 4 kHz PRF pulse train, with an optical slope efficiency of 52% and an optical-to-optical conversion efficiency of 41%. The laser generated 1.5 mJ, 45 ns FWHM, 33kW peak power pulses, and 6.2W of average output. A second mechanically Q-switched laser operating at 10 kHz PRF produced 1mJ, 35kW peak power pulses, generating 11W average power with an optical efficiency of 46%, and a beam quality of 1.4x diffraction limit.

High-frequency ultrasound M-mode monitoring of HIFU ablation in cardiac tissue

NASA Astrophysics Data System (ADS)

Kumon, R. E.; Gudur, M. S. R.; Zhou, Y.; Deng, C. X.

2012-10-01

Effective real-time HIFU lesion detection is important for expanded use of HIFU in interventional electrophysiology (e.g., epicardial ablation of cardiac arrhythmia). The goal of this study was to investigate rapid, high-frequency M-mode ultrasound imaging for monitoring spatiotemporal changes in tissue during HIFU application. The HIFU application (4.33 MHz, 1000 Hz PRF, 50% duty cycle, 1 s exposure, 6100 W/cm2) was perpendicularly applied to porcine cardiac tissue with a high-frequency imaging system (Visualsonics Vevo 770, 55 MHz, 4.5 mm focal distance) confocally aligned. Radiofrequency (RF) M-mode data (1 kHz PRF, 4 s × 7 mm) was acquired before, during, and after HIFU treatment. Gross lesions were compared with M-mode data to correlate lesion and cavity formation. Integrated backscatter, echo-decorrelation parameters, and their cumulative extrema over time were analyzed for automatically identifying lesion width and bubble formation. Cumulative maximum integrated backscatter showed the best results for identifying the final lesion width, and a criterion based on line-to-line decorrelation was proposed for identification of transient bubble activity.

Surgical Re-entry of an Intentionally Replanted Periodontally Compromised Tooth Treated with Platelet Rich Fibrin (PRF): Hopeless to Hopeful.

PubMed

Ryana, Haneet Kour; Srinath, Rashmi; Prakash, Shobha

2016-06-01

Intentional replantation is generally contraindicated in periodontally compromised teeth however, there are reports suggesting that it can be a successful treatment alternative for periodontally involved hopeless teeth. Currently there is dearth of evidence regarding the success of this therapy, especially evidence for the effectiveness of autologous platelet rich fibrin is lacking. We present a case report of a 23-year-old male patient with periodontally hopeless left maxillary central incisor having bone loss extending beyond root apex. The tooth was gently extracted and replanted utilizing root conditioning and combined regenerative therapy (Xenograft, PRF and Type I Collagen Membrane). Surgical re-entry at nine months revealed bone formation in the apical third of the tooth. At one year, 87% radiographic bone gain was accomplished. The improvement in the clinical and radiographic parameters reinforced by the re-entry surgery findings strongly suggest that intentional replantation may be a cost-effective substitute to implants and tooth supported prosthesis in situations where conventional periodontal therapy would yield compromised outcomes.

Surgical Re-entry of an Intentionally Replanted Periodontally Compromised Tooth Treated with Platelet Rich Fibrin (PRF): Hopeless to Hopeful

PubMed Central

Srinath, Rashmi; Prakash, Shobha

2016-01-01

Intentional replantation is generally contraindicated in periodontally compromised teeth however, there are reports suggesting that it can be a successful treatment alternative for periodontally involved hopeless teeth. Currently there is dearth of evidence regarding the success of this therapy, especially evidence for the effectiveness of autologous platelet rich fibrin is lacking. We present a case report of a 23-year-old male patient with periodontally hopeless left maxillary central incisor having bone loss extending beyond root apex. The tooth was gently extracted and replanted utilizing root conditioning and combined regenerative therapy (Xenograft, PRF and Type I Collagen Membrane). Surgical re-entry at nine months revealed bone formation in the apical third of the tooth. At one year, 87% radiographic bone gain was accomplished. The improvement in the clinical and radiographic parameters reinforced by the re-entry surgery findings strongly suggest that intentional replantation may be a cost-effective substitute to implants and tooth supported prosthesis in situations where conventional periodontal therapy would yield compromised outcomes. PMID:27504421

Inhibition of autophagy significantly enhances combination therapy with sorafenib and HDAC inhibitors for human hepatoma cells.

PubMed

Yuan, Hang; Li, Ai-Jun; Ma, Sen-Lin; Cui, Long-Jiu; Wu, Bin; Yin, Lei; Wu, Meng-Chao

2014-05-07

To clarify whether histone deacetylase inhibitors histone deacetylase inhibitors (HDACIs) can sensitize hepatocellular carcinoma (HCC) cells to sorafenib treatment. Bax, Bcl-2, ATG5-ATG12, p21, and p27 protein levels in Hep3B, HepG2, and PLC/PRF/5 cells were examined by Western blot. CCK8 and a fluorometric caspase-3 assay were used to examine cellular viability and apoptosis levels. The effect of Beclin-1 on sensitization of HCC cells to sorafenib was examined by transfecting Beclin-1 siRNA into Hep3B, HepG2, and PLC/PRF/5 cells. Autophagy inhibition enhances the inhibitory effects of vorinostat and sorafenib alone or in combination on HCC cell growth. Vorinostat and sorafenib synergistically induced apoptosis and cell cycle alterations. Western blot data indicated that HDACIs and Beclin-1 knockdown increased the p53 acetylation level. The knockdown of Beclin-1 enhanced the synergistic effect of the combination of vorinostat with sorafenib. HDACIs can sensitize HCC cells to sorafenib treatment by regulating the acetylation level of Beclin-1.

High-Frequency Ultrasound M-mode Imaging for Identifying Lesion and Bubble Activity during High-Intensity Focused Ultrasound Ablation

PubMed Central

Kumon, R. E.; Gudur, M. S. R.; Zhou, Y.; Deng, C. X.

2012-01-01

Effective real-time monitoring of high-intensity focused ultrasound (HIFU) ablation is important for application of HIFU technology in interventional electrophysiology. This study investigated rapid, high-frequency M-mode ultrasound imaging for monitoring spatiotemporal changes during HIFU application. HIFU (4.33 MHz, 1 kHz PRF, 50% duty cycle, 1 s, 2600 – 6100 W/cm2) was applied to ex-vivo porcine cardiac tissue specimens with a confocally and perpendicularly aligned high-frequency imaging system (Visualsonics Vevo 770, 55 MHz center frequency). Radiofrequency (RF) data from M-mode imaging (1 kHz PRF, 2 s × 7 mm) was acquired before, during, and after HIFU treatment (n = 12). Among several strategies, the temporal maximum integrated backscatter with a threshold of +12 dB change showed the best results for identifying final lesion width (receiver-operating characteristic curve area 0.91 ± 0.04, accuracy 85 ± 8%, as compared to macroscopic images of lesions). A criterion based on a line-to-line decorrelation coefficient is proposed for identification of transient gas bodies. PMID:22341055

The use of leucocyte and platelet-rich fibrin in socket management and ridge preservation: a split-mouth, randomized, controlled clinical trial.

PubMed

Temmerman, Andy; Vandessel, Jeroen; Castro, Ana; Jacobs, Reinhilde; Teughels, Wim; Pinto, Nelson; Quirynen, Marc

2016-11-01

To investigate the influence of the use L-PRF as a socket filling material and its ridge preservation properties. Twenty-two patients in need of single bilateral and closely symmetrical tooth extractions in the maxilla or mandible were included in a split-mouth RCT. Treatments were randomly assigned (L-PRF socket filling versus natural healing). CBCT scans were obtained after tooth extraction and three months. Scans were evaluated by superimposition using the original DICOM data. Mean ridge width differences between timepoints were measured at three levels below the crest on both the buccal and lingual sides (crest -1 mm (primary outcome variable), -3 mm and -5 mm). Mean vertical height changes at the buccal were -1.5 mm (±1.3) for control sites and 0.5 mm (±2.3) for test sites (p < 0.005). At the buccal side, control sites values were, respectively, -2.1 (±2.5), -0.3 mm (±0.3) (p < 0.005) and -0.1 mm (±0.0), and test sites values were, respectively, -0.6 mm (±2.2) (p < 0.005), -0.1 mm (±0.3) and 0.0 mm (±0.1). Significant differences (p < 0.005) were found for total width reduction between test (-22.84%) and control sites (-51.92%) at 1 mm below crest level. Significant differences were found for socket fill (visible mineralized bone) between test (94.7%) and control sites (63.3%). The use of L-PRF as a socket filling material to achieve preservation of horizontal and vertical ridge dimension at three  months after tooth extraction is beneficial. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

A patient-mount navigated intervention system for spinal diseases and its clinical trial on percutaneous pulsed radiofrequency stimulation of dorsal root ganglion.

PubMed

Yang, Chi-Lin; Yang, Been-Der; Lin, Mu-Lien; Wang, Yao-Hung; Wang, Jaw-Lin

2010-10-01

Development of a patient-mount navigated intervention (PaMNI) system for spinal diseases. An in vivo clinical human trial was conducted to validate this system. To verify the feasibility of the PaMNI system with the clinical trial on percutaneous pulsed radiofrequency stimulation of dorsal root ganglion (PRF-DRG). Two major image guiding techniques, i.e., computed tomography (CT)-guided and fluoro-guided, were used for spinal intervention. The CT-guided technique provides high spatial resolution, and is claimed to be more accurate than the fluoro-guided technique. Nevertheless, the CT-guided intervention usually reaches higher radiograph exposure than the fluoro-guided counterpart. Some navigated intervention systems were developed to reduce the radiation of CT-guided intervention. Nevertheless, these systems were not popularly used due to the longer operation time, a new protocol for surgeons, and the availability of such a system. The PaMNI system includes 3 components, i.e., a patient-mount miniature tracking unit, an auto-registered reference frame unit, and a user-friendly image processing unit. The PRF-DRG treatment was conducted to find the clinical feasibility of this system. The in vivo clinical trial showed that the accuracy, visual analog scale evaluation after surgery, and radiograph exposure of the PaMNI-guided technique are comparable to the one of conventional fluoro-guided technique, while the operation time is increased by 5 minutes. Combining the virtues of fluoroscopy and CT-guided techniques, our navigation system is operated like a virtual fluoroscopy with augmented CT images. This system elevates the performance of CT-guided intervention and reduces surgeons' radiation exposure risk to a minimum, while keeping low radiation dose to patients like its fluoro-guided counterpart. The clinical trial of PRF-DRG treatment showed the clinical feasibility and efficacy of this system.

Effect of acoustic parameters on the cavitation behavior of SonoVue microbubbles induced by pulsed ultrasound.

PubMed

Lin, Yutong; Lin, Lizhou; Cheng, Mouwen; Jin, Lifang; Du, Lianfang; Han, Tao; Xu, Lin; Yu, Alfred C H; Qin, Peng

2017-03-01

SonoVue microbubbles could serve as artificial nuclei for ultrasound-triggered stable and inertial cavitation, resulting in beneficial biological effects for future therapeutic applications. To optimize and control the use of the cavitation of SonoVue bubbles in therapy while ensuring safety, it is important to comprehensively understand the relationship between the acoustic parameters and the cavitation behavior of the SonoVue bubbles. An agarose-gel tissue phantom was fabricated to hold the SonoVue bubble suspension. 1-MHz transmitting transducer calibrated by a hydrophone was used to trigger the cavitation of SonoVue bubbles under different ultrasonic parameters (i.e., peak rarefactional pressure (PRP), pulse repetition frequency (PRF), and pulse duration (PD)). Another 7.5-MHz focused transducer was employed to passively receive acoustic signals from the exposed bubbles. The ultraharmonics and broadband intensities in the acoustic emission spectra were measured to quantify the extent of stable and inertial cavitation of SonoVue bubbles, respectively. We found that the onset of both stable and inertial cavitation exhibited a strong dependence on the PRP and PD and a relatively weak dependence on the PRF. Approximate 0.25MPa PRP with more than 20μs PD was considered to be necessary for ultraharmonics emission of SonoVue bubbles, and obvious broadband signals started to appear when the PRP exceeded 0.40MPa. Moreover, the doses of stable and inertial cavitation varied with the PRP. The stable cavitation dose initially increased with increasing PRP, and then decreased rapidly after 0.5MPa. By contrast, the inertial cavitation dose continuously increased with increasing PRP. Finally, the doses of both stable and inertial cavitation were positively correlated with PRF and PD. These results could provide instructive information for optimizing future therapeutic applications of SonoVue bubbles. Copyright © 2016 Elsevier B.V. All rights reserved.

Influence of geometric and material properties on artifacts generated by interventional MRI devices: Relevance to PRF-shift thermometry

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tatebe, Ken, E-mail: Ken.Tatebe@gmail.com; Ramsay, Elizabeth; Kazem, Mohammad

2016-01-15

Purpose: Magnetic resonance imaging (MRI) is capable of providing valuable real-time feedback during medical procedures, partly due to the excellent soft-tissue contrast available. Several technical hurdles still exist to seamless integration of medical devices with MRI due to incompatibility of most conventional devices with this imaging modality. In this study, the effect of local perturbations in the magnetic field caused by the magnetization of medical devices was examined using finite element analysis modeling. As an example, the influence of the geometric and material characteristics of a transurethral high-intensity ultrasound applicator on temperature measurements using proton resonance frequency (PRF)-shift thermometry wasmore » investigated. Methods: The effect of local perturbations in the magnetic field, caused by the magnetization of medical device components, was examined using finite element analysis modeling. The thermometry artifact generated by a transurethral ultrasound applicator was simulated, and these results were validated against analytic models and scans of an applicator in a phantom. Several parameters were then varied to identify which most strongly impacted the level of simulated thermometry artifact, which varies as the applicator moves over the course of an ablative high-intensity ultrasound treatment. Results: Key design parameters identified as having a strong influence on the magnitude of thermometry artifact included the susceptibility of materials and their volume. The location of components was also important, particularly when positioned to maximize symmetry of the device. Finally, the location of component edges and the inclination of the device relative to the magnetic field were also found to be important factors. Conclusions: Previous design strategies to minimize thermometry artifact were validated, and novel design strategies were identified that substantially reduce PRF-shift thermometry artifacts for a variety of device orientations. These new strategies are being incorporated into the next generation of applicators. The general strategy described in this study can be applied to the design of other interventional devices intended for use with MRI.« less

Handling Qualities of a Large Civil Tiltrotor in Hover using Translational Rate Command

NASA Technical Reports Server (NTRS)

Malpica, Carlos A.; Theodore, Colin R.; Lawrence, Ben; Lindsey, James; Blanken, Chris

2012-01-01

A Translational Rate Command (TRC) control law has been developed to enable low speed maneuvering of a large civil tiltrotor with minimal pitch changes by means of automatic nacelle angle deflections for longitudinal velocity control. The nacelle actuator bandwidth required to achieve Level 1 handling qualities in hover and the feasibility of additional longitudinal cyclic control to augment low bandwidth nacelle actuation were investigated. A frequency-domain handling qualities criterion characterizing TRC response in terms of bandwidth and phase delay was proposed and validated against a piloted simulation conducted on the NASA-Ames Vertical Motion Simulator. Seven experimental test pilots completed evaluations in the ADS-33E-PRF Hover Mission Task Element (MTE) for a matrix of nacelle actuator bandwidths, equivalent rise times and control response sensitivities, and longitudinal cyclic control allocations. Evaluated against this task, longitudinal phase delay shows the Level 1 boundary is around 0.4 0.5 s. Accordingly, Level 1 handling qualities were achieved either with a nacelle actuator bandwidth greater than 4 rad/s, or by employing longitudinal cyclic control to augment low bandwidth nacelle actuation.

Progress in using hydroxymethylated resorcinol coupling agent to improve bond durability to wood

Treesearch

Alfred W. Christiansen

2001-01-01

In the mid-1990s, researchers at the Forest Products Laboratory developed a coupling agent, hydroxymethylated resorcinol (HMR), that has the ability to enhance adhesive bonds between wood and nontraditional adhesives (Vick and others 1995, 1996). HMR is also effective in promoting durable bonding of phenol-resorcinol- formaldehyde (PRF) adhesives to CCA-treated...

Small Unit Operations

DTIC Science & Technology

1998-06-29

regardless of size; therefore very small systems may have JA ~ 0.5, whereas bigger systems may have to be buried , making /^ < 1. It would be desirable to...OATn PaQ {^xfRcTjPRF /D\\ 4 SNR= MrTO U) =32dB’ «"> It is worth noting here the capabilities of the SAR in transmitting and in receiving messages

An analysis of two open reading frames (ORF3 and ORF4) of rat hepatitis E virus genome using its infectious cDNA clones with mutations in ORF3 or ORF4.

PubMed

Tanggis; Kobayashi, Tominari; Takahashi, Masaharu; Jirintai, Suljid; Nishizawa, Tsutomu; Nagashima, Shigeo; Nishiyama, Takashi; Kunita, Satoshi; Hayama, Emiko; Tanaka, Takeshi; Mulyanto; Okamoto, Hiroaki

2018-04-02

Rat hepatitis E virus (ratHEV) genome has four open reading frames (ORFs: ORF1, ORF2, ORF3 and ORF4). The functions of ORF3 and ORF4 are unknown. An infectious cDNA clone (pUC-ratELOMB-131L_wt, wt) and its derivatives including ORF3-defective (ΔORF3) and ORF4-defective (ΔORF4) mutants, were constructed and their full-length RNA transcripts transfected into PLC/PRF/5 cells. ΔORF3 replicated as efficiently as wt in cells. However, ≤1/1000 of the number of progenies were detectable in the culture supernatant of ΔORF3-infected cells compared with wt-infected cells. ORF4 protein was not detectable in ratHEV-infected cells or in the liver tissues of ratHEV-infected rats. No marked differences were noted between wt and ΔORF4 regarding the viral replication and protein expression. ORF3 mutants with proline-to-leucine mutations at amino acids (aa) 93, 96 and/or 98 in ORF3 were constructed and transfected into PLC/PRF/5 cells. Wt and an ORF3 mutant with leucine at aa 98 (ORF3-L98) replicated efficiently (density 1.15-1.16 g/cm 3 ), while ORF3-L93 + L96 exhibited a decreased viral release and banded at 1.26-1.27 g/cm 3 , similar to ΔORF3. In conclusion, the ORF3 protein, especially its proline residues at aa 93 and 96, is essential for the release of membrane-associated ratHEV particles, and ORF4 is unnecessary for the replication of ratHEV. Copyright © 2018 Elsevier B.V. All rights reserved.

Dynamic Virtual Credit Card Numbers

NASA Astrophysics Data System (ADS)

Molloy, Ian; Li, Jiangtao; Li, Ninghui

Theft of stored credit card information is an increasing threat to e-commerce. We propose a dynamic virtual credit card number scheme that reduces the damage caused by stolen credit card numbers. A user can use an existing credit card account to generate multiple virtual credit card numbers that are either usable for a single transaction or are tied with a particular merchant. We call the scheme dynamic because the virtual credit card numbers can be generated without online contact with the credit card issuers. These numbers can be processed without changing any of the infrastructure currently in place; the only changes will be at the end points, namely, the card users and the card issuers. We analyze the security requirements for dynamic virtual credit card numbers, discuss the design space, propose a scheme using HMAC, and prove its security under the assumption the underlying function is a PRF.

Non-invasive transcranial stimulation of rat abducens nerve by focused ultrasound

PubMed Central

Kim, Hyungmin; Taghados, Seyed Javid; Fischer, Krisztina; Maeng, Lee-So; Park, Shinsuk; Yoo, Seung-Schik

2012-01-01

Non-pharmacological and non-surgical transcranial modulation of the nerve function may provide new opportunities in evaluation and treatment of cranial nerve diseases. This study investigates the possibility of using low-intensity transcranial focused ultrasound (FUS) to selectively stimulate the rat abducens nerve located above the base of the skull. FUS (frequencies of 350 kHz and 650 kHz) operating in a pulsed mode was applied to the abducens nerve of Sprague-Dawley rats under stereotactic guidance. The abductive eyeball movement ipsilateral to the side of sonication was observed at 350 kHz, using the 0.36 msec tone burst duration (TBD), 1.5 kHz pulse repetition frequency (PRF), and the overall sonication duration of 200 msec. Histological and behavioral monitoring showed no signs of disruption in the blood brain barrier (BBB) as well as no damage to the nerves and adjacent brain tissue resulting from the sonication. As a novel functional neuro-modulatory modality, the pulsed application of FUS has potential in diagnostic and therapeutic applications in diseases of the peripheral nervous system. PMID:22763009

Adhesive bonding of wood treated with ACQ and copper azole preservatives

Treesearch

Linda F. Lorenz; Charles Frihart

2006-01-01

Treated wood has generally been more difficult to bond than untreated wood for a variety of reasons. Alkaline copper quat (ACQ) and copper azole (CA-B), the most prominent substitutes for chromated copper arsenate (CCA), are difficult to bond consistently. Using a phenol-resorcinol- formaldehyde (PRF) adhesive formulated for bonding to CCA-treated wood, we examined the...

New GREEN Products for the Military Aviation Maintenance Community

DTIC Science & Technology

2012-05-01

Petroleum Base, for Preservation and Operation • MIL -H-19457 - Hydraulic Fluid, Fire-resistant, Non-neurotoxic • MIL -H- 81019 ...ENHANCEMENT STEWARDSHIP EXCELLENCE WORKFORCE DEVELOPMENT 14 New GREEN products (NAVAIR) MIL -PRF-85570...aircraft spot cleaners Mil -C-43616 • 6850-01-578-4978 type I • 6850-01-581-9413 type II • 6850-01-587-3779 type I

Low Temperature Cure Powder Coatings

DTIC Science & Technology

2013-05-01

operations Minimize worker exposure to VOCs, HAPs, and hexavalent chrome Passed objective AF Engr Qual Plan = Air Force Engineer Quality Plan MIL-PRF...Inconclusive • Inconclusive • Not applicable (N/A) • Passed criteria Reduction of hexavalent chromium use • Passed objective Reduction of hazardous...compliance. The implementation of the OSHA Final Rule designating the permissible exposure limit (PEL) for hexavalent chromium is a significant

Comparative Evaluation of Platelet Rich Fibrin and Dehydrated Amniotic Membrane for the Treatment of Gingival Recession- A Clinical Study

PubMed Central

Jaiswal, Gagan Rajesh; Kumathalli, Kanteshwari; Kumar, Rajesh; Singh, Alisha; Sarwan, Aakrti

2017-01-01

Introduction The main objective of any therapeutic intervention aimed at root coverage is to restore the tissue margin to the cemento-enamel junction and to regenerate the lost periodontium. Aim To compare the effectiveness of Platelet Rich Fibrin (PRF) and Amniotic Membrane (AM) in the treatment of gingival recession by Coronally Advanced Flap (CAF) Technique. Materials and Methods Thirty systemically healthy patients who met inclusion-exclusion criteria were selected. After Phase-I therapy, patients were randomly allocated to one of the groups; PRF (Group-A) and Amnion Group (Group-B). Clinical parameters like Plaque Index (PI), Recession Depth (RD) and Width of Keratinized Gingiva (WKG) were measured on the baseline day, three months and six months postoperatively. Mann-Whitney test and Wilcoxon signed ranks test were applied for intergroup and intragroup comparisons respectively. Results Intergroup comparison between platelet rich fibrin and amniotic membrane showed statistically insignificant difference in the recession depth and width of keratinized gingiva at three and six months postoperatively. Conclusion Both the membranes were equally effective in terms of recession coverage and increase in width of keratinized gingiva. PMID:28969268

Piloted Simulator Investigation of Techniques to Achieve Attitude Command Response with Limited Authority Servos

NASA Technical Reports Server (NTRS)

Key, David L.; Heffley, Robert K.

2002-01-01

The purpose of the study was to develop generic design principles for obtaining attitude command response in moderate to aggressive maneuvers without increasing SCAS series servo authority from the existing +/- 10%. In particular, to develop a scheme that would work on the UH-60 helicopter so that it can be considered for incorporation in future upgrades. The basic math model was a UH-60A version of GENHEL. The simulation facility was the NASA-Ames Vertical Motion Simulator (VMS). Evaluation tasks were Hover, Acceleration-Deceleration, and Sidestep, as defined in ADS-33D-PRF for Degraded Visual Environment (DVE). The DVE was adjusted to provide a Usable Cue Environment (UCE) equal to two. The basic concept investigated was the extent to which the limited attitude command authority achievable by the series servo could be supplemented by a 10%/sec trim servo. The architecture used provided angular rate feedback to only the series servo, shared the attitude feedback between the series and trim servos, and when the series servo approached saturation the attitude feedback was slowly phased out. Results show that modest use of the trim servo does improve pilot ratings, especially in and around hover. This improvement can be achieved with little degradation in response predictability during moderately aggressive maneuvers.

Systems Level Analyses Reveal Multiple Regulatory Activities of CodY Controlling Metabolism, Motility and Virulence in Listeria monocytogenes

PubMed Central

Lobel, Lior; Herskovits, Anat A.

2016-01-01

Bacteria sense and respond to many environmental cues, rewiring their regulatory network to facilitate adaptation to new conditions/niches. Global transcription factors that co-regulate multiple pathways simultaneously are essential to this regulatory rewiring. CodY is one such global regulator, controlling expression of both metabolic and virulence genes in Gram-positive bacteria. Branch chained amino acids (BCAAs) serve as a ligand for CodY and modulate its activity. Classically, CodY was considered to function primarily as a repressor under rich growth conditions. However, our previous studies of the bacterial pathogen Listeria monocytogenes revealed that CodY is active also when the bacteria are starved for BCAAs. Under these conditions, CodY loses the ability to repress genes (e.g., metabolic genes) and functions as a direct activator of the master virulence regulator gene, prfA. This observation raised the possibility that CodY possesses multiple functions that allow it to coordinate gene expression across a wide spectrum of metabolic growth conditions, and thus better adapt bacteria to the mammalian niche. To gain a deeper understanding of CodY’s regulatory repertoire and identify direct target genes, we performed a genome wide analysis of the CodY regulon and DNA binding under both rich and minimal growth conditions, using RNA-Seq and ChIP-Seq techniques. We demonstrate here that CodY is indeed active (i.e., binds DNA) under both conditions, serving as a repressor and activator of different genes. Further, we identified new genes and pathways that are directly regulated by CodY (e.g., sigB, arg, his, actA, glpF, gadG, gdhA, poxB, glnR and fla genes), integrating metabolism, stress responses, motility and virulence in L. monocytogenes. This study establishes CodY as a multifaceted factor regulating L. monocytogenes physiology in a highly versatile manner. PMID:26895237

Links between land use change and recent dry season droughts in Amazonia

NASA Astrophysics Data System (ADS)

Khanna, J.; Medvigy, D.

2012-12-01

The Amazon region experienced catastrophic and unusually severe droughts in 2005 and 2010. These two droughts were phenomenologically different from the other, more common, El Niño-related droughts. Whereas El Niño-related droughts mostly affect the eastern and south-eastern parts of the region during the wet season (December-March), the droughts of 2005 and 2010 were most severe during the dry season (June-August) and affected the southern and western parts of the Amazon. A global warming driven mechanism has been suggested for these droughts wherein decreased moisture transport into the basin during the dry season is caused by anomalously high tropical north Atlantic SSTs, which weaken the northern hemisphere Hadley cell. But the facts that dry season droughts have been historically rare in this region and that the 2005 and 2010 droughts were strongest around locations of recent land use change activity suggest that deforestation may be contributing to this inter-annual variability in precipitation. This study addresses this research question by numerically modeling the 2005 and 2010 drought events for two land use scenarios, one of which (Deforested or DEF) represents the current state of land use in the Amazon and the other (Pristine Forest or PRF) represents a scenario of no deforestation. A variable resolution GCM, the Ocean-Land-Atmosphere Model (OLAM), is used to model these events. Land surface processes and soil moisture during the drought period are simulated using the Land Ecosystem Atmosphere Feedback model. The state of land cover in the Amazon in the two drought years is obtained from satellite-based land cover maps. The land grid has a variable resolution ranging from ≈75km in the South American sector to ≈200km elsewhere. This variable-resolution approach helps resolve topographic features and the medium-to-large scale land use patches in the Amazon area. The atmospheric runs are forced by National Oceanic and Atmospheric Administration weekly sea-surface temperature data. Soil moisture initial conditions were obtained from 8-year spin-ups for DEF and PRF. Then, ensembles of 18 month simulations were carried out, starting in June of 2004 and 2009. The ensembles consisted of 5 runs for each of the DEF and PRF experiments and are designed to reduce the effects of natural climate variability on the model results. Results are analyzed to test whether the intensity of the droughts, as measured by a water deficit index like maximum climatological water deficit (MCWD), increases from the PRF to the DEF case. An analysis of the statistical differences between the values of various meteorological and hydrological variables as obtained from the two land use scenarios will be presented. Thus this study will help both qualify and quantify the extent to which land use change can intensify a drought event.

Frequency Diversity for Improving Synthetic Aperture Radar Imaging

DTIC Science & Technology

2009-03-01

for broadside spotlight SAR imaging is shown to be δθ = λ 4Yo . (2.34) When θ is small, as is often the case in spotlight SAR imaging, the required...maximum distance ∆y between samples along the y-axis is shown to be ∆y ≤ λRc 4Yo . (2.35) With platform velocity vy along the y-axis, the minimum PRF is

STS-134 crew during PDRS PRF ADV (AMS) traiining

NASA Image and Video Library

2011-03-23

JSC2011-E-028161 (23 March 2011) --- NASA astronauts Greg Chamitoff (foreground), STS-134 mission specialist; and Greg H. Johnson, pilot, participate in an exercise in the systems engineering simulator in the Avionics Systems Laboratory at NASA's Johnson Space Center. The facility includes moving scenes of full-sized International Space Station components over a simulated Earth. Photo credit: NASA or National Aeronautics and Space Administration

High PRF high current switch

DOEpatents

Moran, Stuart L.; Hutcherson, R. Kenneth

1990-03-27

A triggerable, high voltage, high current, spark gap switch for use in pu power systems. The device comprises a pair of electrodes in a high pressure hydrogen environment that is triggered by introducing an arc between one electrode and a trigger pin. Unusually high repetition rates may be obtained by undervolting the switch, i.e., operating the trigger at voltages much below the self-breakdown voltage of the device.

Electromagnetic Environmental Effects System Testing

DTIC Science & Technology

2009-09-02

Procedure (TOP) 1-2-511 Electromagnetic Environmental Effects System Testing 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER...airborne, sea, space, and ground systems , including associated ordnance, as stated in military standard (MIL-STD)-464A “Electromagnetic Environmental...Effects Requirement for Systems ”, as well as ADS-37A-PRF “Aeronautical Design Standard for the Electromagnetic Environmental Effects (E3) Performance and

Studies on Radar and Non-radar Sensor Networks

DTIC Science & Technology

2006-06-15

the following sections. ubiquitous and persistent sensor sources such as "* Organic sensors (e.g., radar, electro- optic and infrared, III. SITUATION...repetition frequency (PRF). Under these circumstances, target RSN, but in noncoherent systems as well. The latter scenario is more challenging as...signal propagation models. Section III and IV analyzes coherent andseletio an Ga ssin u equl me n trge mo els In [3] noncoherent detection

Two-dimensional Shear Wave Elastography on Conventional Ultrasound Scanners with Time Aligned Sequential Tracking (TAST) and Comb-push Ultrasound Shear Elastography (CUSE)

PubMed Central

Song, Pengfei; Macdonald, Michael C.; Behler, Russell H.; Lanning, Justin D.; Wang, Michael H.; Urban, Matthew W.; Manduca, Armando; Zhao, Heng; Callstrom, Matthew R.; Alizad, Azra; Greenleaf, James F.; Chen, Shigao

2014-01-01

Two-dimensional (2D) shear wave elastography presents 2D quantitative shear elasticity maps of tissue, which are clinically useful for both focal lesion detection and diffuse disease diagnosis. Realization of 2D shear wave elastography on conventional ultrasound scanners, however, is challenging due to the low tracking pulse-repetition-frequency (PRF) of these systems. While some clinical and research platforms support software beamforming and plane wave imaging with high PRF, the majority of current clinical ultrasound systems do not have the software beamforming capability, which presents a critical challenge for translating the 2D shear wave elastography technique from laboratory to clinical scanners. To address this challenge, this paper presents a Time Aligned Sequential Tracking (TAST) method for shear wave tracking on conventional ultrasound scanners. TAST takes advantage of the parallel beamforming capability of conventional systems and realizes high PRF shear wave tracking by sequentially firing tracking vectors and aligning shear wave data in the temporal direction. The Comb-push Ultrasound Shear Elastography (CUSE) technique was used to simultaneously produce multiple shear wave sources within the field-of-view (FOV) to enhance shear wave signal-to-noise-ratio (SNR) and facilitate robust reconstructions of 2D elasticity maps. TAST and CUSE were realized on a conventional ultrasound scanner (the General Electric LOGIQ E9). A phantom study showed that the shear wave speed measurements from the LOGIQ E9 were in good agreement to the values measured from other 2D shear wave imaging technologies. An inclusion phantom study showed that the LOGIQ E9 had comparable performance to the Aixplorer (Supersonic Imagine) in terms of bias and precision in measuring different sized inclusions. Finally, in vivo case analysis of a breast with a malignant mass, and a liver from a healthy subject demonstrated the feasibility of using the LOGIQ E9 for in vivo 2D shear wave elastography. These promising results indicate that the proposed technique can enable the implementation of 2D shear wave elastography on conventional ultrasound scanners and potentially facilitate wider clinical applications with shear wave elastography. PMID:25643079

STS-134 crew during PDRS PRF ADV (AMS) traiining

NASA Image and Video Library

2011-03-23

JSC2011-E-028173 (23 March 2011) --- European Space Agency astronaut Roberto Vittori (right) and NASA astronaut Andrew Feustel, both STS-134 mission specialists, participate in an exercise in the systems engineering simulator in the Avionics Systems Laboratory at NASA's Johnson Space Center. The facility includes moving scenes of full-sized International Space Station components over a simulated Earth. Photo credit: NASA or National Aeronautics and Space Administration

STS-134 crew during PDRS PRF ADV (AMS) traiining

NASA Image and Video Library

2011-03-23

JSC2011-E-028166 (23 March 2011) --- European Space Agency astronaut Roberto Vittori (right) and NASA astronaut Andrew Feustel, both STS-134 mission specialists, participate in an exercise in the systems engineering simulator in the Avionics Systems Laboratory at NASA's Johnson Space Center. The facility includes moving scenes of full-sized International Space Station components over a simulated Earth. Photo credit: NASA or National Aeronautics and Space Administration

Seat Vibration in Military Propeller Aircraft: Characterization, Exposure Assessment, and Mitigation

DTIC Science & Technology

2006-05-01

vibration were fatigue and reduced performance during long missions. assessed in accordance with current international guidelines (ISO 2631 - The incident...Measurements and Flight Configurations ( BPF ) of these aircraft. The health risk and comfort reaction of the vibration exposures were assessed in For...constant bandwidth rms accelerations at the PRF atively level flight at altitudes ranging between 15,000 and BPF of each aircraft were evaluated. For

Literature Review: Crud Formation at the Liquid/Liquid Interface of TBP-Based Solvent-Extraction Processes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Delegard, Calvin H.; Casella, Amanda J.

2016-09-30

This report summarizes the literature reviewed on crud formation at the liquid:liquid interface of solvent extraction processes. The review is focused both on classic PUREX extraction for industrial reprocessing, especially as practiced at the Hanford Site, and for those steps specific to plutonium purification that were used at the Plutonium Reclamation Facility (PRF) within the Plutonium Finishing Plant (PFP) at the Hanford Site.

CADAT network translator

NASA Technical Reports Server (NTRS)

Pitts, E. R.

1981-01-01

Program converts cell-net data into logic-gate models for use in test and simulation programs. Input consists of either Place, Route, and Fold (PRF) or Place-and-Route-in-Two-Dimensions (PR2D) layout data deck. Output consists of either Test Pattern Generator (TPG) or Logic-Simulation (LOGSIM) logic circuitry data deck. Designer needs to build only logic-gate-model circuit description since program acts as translator. Language is FORTRAN IV.

Multiple Cis-acting elements modulate programmed -1 ribosomal frameshifting in Pea enation mosaic virus

PubMed Central

Gao, Feng; Simon, Anne E.

2016-01-01

Programmed -1 ribosomal frameshifting (-1 PRF) is used by many positive-strand RNA viruses for translation of required products. Despite extensive studies, it remains unresolved how cis-elements just downstream of the recoding site promote a precise level of frameshifting. The Umbravirus Pea enation mosaic virus RNA2 expresses its RNA polymerase by -1 PRF of the 5′-proximal ORF (p33). Three hairpins located in the vicinity of the recoding site are phylogenetically conserved among Umbraviruses. The central Recoding Stimulatory Element (RSE), located downstream of the p33 termination codon, is a large hairpin with two asymmetric internal loops. Mutational analyses revealed that sequences throughout the RSE and the RSE lower stem (LS) structure are important for frameshifting. SHAPE probing of mutants indicated the presence of higher order structure, and sequences in the LS may also adapt an alternative conformation. Long-distance pairing between the RSE and a 3′ terminal hairpin was less critical when the LS structure was stabilized. A basal level of frameshifting occurring in the absence of the RSE increases to 72% of wild-type when a hairpin upstream of the slippery site is also deleted. These results suggest that suppression of frameshifting may be needed in the absence of an active RSE conformation. PMID:26578603

Time-Dependent Simulations of Fast-Wave Heated High-Non-Inductive-Fraction H-Mode Plasmas in the National Spherical Torus Experiment Upgrade

NASA Astrophysics Data System (ADS)

Taylor, Gary; Bertelli, Nicola; Gerhardt, Stefan P.; Hosea, Joel C.; Mueller, Dennis; Perkins, Rory J.; Poli, Francesca M.; Wilson, James R.; Raman, Roger

2017-10-01

30 MHz fast-wave heating may be an effective tool for non-inductively ramping low-current plasmas to a level suitable for initiating up to 12 MW of neutral beam injection on the National Spherical Tokamak Experiment Upgrade (NSTX-U). Previously on NSTX 30 MHz fast wave heating was shown to efficiently and rapidly heat electrons; at the NSTX maximum axial toroidal magnetic field (BT(0)) of 0.55 T, 1.4 MW of 30 MHz heating increased the central electron temperature from 0.2 to 2 keV in 30 ms and generated an H-mode plasma with a non-inductive fraction (fNI) ˜ 0.7 at a plasma current (Ip) of 300 kA. NSTX-U will operate at BT(0) up to 1 T, with up to 4 MW of 30 MHz power (Prf). Predictive TRANSP free boundary transport simulations, using the TORIC full wave spectral code to calculate the fast-wave heating and current drive, have been run for NSTX-U Ip = 300 kA H-mode plasmas. Favorable scaling of fNI with 30 MHz heating power is predicted, with fNI ≥ 1 for Prf ≥ 2 MW.

Single-mode, All-Solid-State Nd:YAG Laser Pumped UV Converter

NASA Technical Reports Server (NTRS)

Prasad, Narasimha S.; Armstrong, Darrell, J.; Edwards, William C.; Singh, Upendra N.

2008-01-01

In this paper, the status of a high-energy, all solid-state Nd:YAG laser pumped nonlinear optics based UV converter development is discussed. The high-energy UV transmitter technology is being developed for ozone sensing applications from space based platforms using differential lidar technique. The goal is to generate greater than 200 mJ/pulse with 10-50 Hz PRF at wavelengths of 308 nm and 320 nm. A diode-pumped, all-solid-state and single longitudinal mode Nd:YAG laser designed to provide conductively cooled operation at 1064 nm has been built and tested. Currently, this pump laser provides an output pulse energy of >1 J/pulse at 50 Hz PRF and a pulsewidth of 22 ns with an electrical-to-optical system efficiency of greater than 7% and a M(sup 2) value of <2. The single frequency UV converter arrangement basically consists of an IR Optical Parametric Oscillator (OPO) and a Sum Frequency Generator (SFG) setups that are pumped by 532 nm wavelength obtained via Second Harmonic Generation (SHG). In this paper, the operation of an inter cavity SFG with CW laser seeding scheme generating 320 nm wavelength is presented. Efforts are underway to improve conversion efficiency of this mJ class UV converter by modifying the spatial beam profile of the pump laser.

Integration of gene normalization stages and co-reference resolution using a Markov logic network.

PubMed

Dai, Hong-Jie; Chang, Yen-Ching; Tsai, Richard Tzong-Han; Hsu, Wen-Lian

2011-09-15

Gene normalization (GN) is the task of normalizing a textual gene mention to a unique gene database ID. Traditional top performing GN systems usually need to consider several constraints to make decisions in the normalization process, including filtering out false positives, or disambiguating an ambiguous gene mention, to improve system performance. However, these constraints are usually executed in several separate stages and cannot use each other's input/output interactively. In this article, we propose a novel approach that employs a Markov logic network (MLN) to model the constraints used in the GN task. Firstly, we show how various constraints can be formulated and combined in an MLN. Secondly, we are the first to apply the two main concepts of co-reference resolution-discourse salience in centering theory and transitivity-to GN models. Furthermore, to make our results more relevant to developers of information extraction applications, we adopt the instance-based precision/recall/F-measure (PRF) in addition to the article-wide PRF to assess system performance. Experimental results show that our system outperforms baseline and state-of-the-art systems under two evaluation schemes. Through further analysis, we have found several unexplored challenges in the GN task. hongjie@iis.sinica.edu.tw Supplementary data are available at Bioinformatics online.

LANSCE-R WIRE-SCANNER ANALOG FRONT-END ELECTRONICS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gruchalla, Michael E.

2011-01-01

A new AFE is being developed for the new LANSCE-R wire-scanner systems. The new AFE is implemented in a National Instruments Compact RIO (cRIO) module installed a BiRa 4U BiRIO cRIO chassis specifically designed to accommodate the cRIO crate and all the wire-scanner interface, control and motor-drive electronics. A single AFE module provides interface to both X and Y wire sensors using true DC coupled transimpedance amplifiers providing collection of the wire charge signals, real-time wire integrity verification using the normal dataacquisition system, and wire bias of 0V to +/-50V. The AFE system is designed to accommodate comparatively long macropulsesmore » (>1ms) with high PRF (>120Hz) without the need to provide timing signals. The basic AFE bandwidth is flat from true DC to 50kHz with a true first-order pole at 50kHz. Numeric integration in the cRIO FPGA provides real-time pulse-to-pulse numeric integration of the AFE signal to compute the total charge collected in each macropulse. This method of charge collection eliminates the need to provide synchronization signals to the wire-scanner AFE while providing the capability to accurately record the charge from long macropulses at high PRF.« less

The Antimicrobial Peptide Human Beta-Defensin-3 Is Induced by Platelet-Released Growth Factors in Primary Keratinocytes

PubMed Central

Lammel, Justus; Tohidnezhad, Mersedeh; Lippross, Sebastian; Behrendt, Peter; Klüter, Tim; Pufe, Thomas; Cremer, Jochen; Jahr, Holger; Rademacher, Franziska; Gläser, Regine; Harder, Jürgen

2017-01-01

Platelet-released growth factors (PRGF) and its related clinically used formulations (e.g., Vivostat Platelet-Rich Fibrin (PRF®)) contain a variety of chemokines, cytokines, and growth factors and are therefore used to support healing of chronic, hard-to-heal, or infected wounds. Human beta-defensin-3 (hBD-3) is an antimicrobial peptide inducibly expressed in human keratinocytes especially upon wounding. The potent antimicrobial activity of hBD-3 together with its wound closure-promoting activities suggests that hBD-3 may play a crucial role in wound healing. Therefore, we analyzed the influence of PRGF on hBD-3 expression in human primary keratinocytes in vitro. In addition, we investigated the influence of Vivostat PRF on hBD-3 expression in artificially generated human skin wounds in vivo. PRGF treatment of primary keratinocytes induced a significant, concentration- and time-dependent increase in hBD-3 gene expression which was partially mediated by the epidermal growth factor receptor (EGFR). In line with these cell culture data, in vivo experiments revealed an enhanced hBD-3 expression in experimentally produced human wounds after the treatment with Vivostat PRF. Thus, the induction of hBD-3 may contribute to the beneficial effects of thrombocyte concentrate lysates in the treatment of chronic or infected wounds. PMID:28811680