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PURPOSE: Developmental stuttering is a complex and multifaceted neurodevelopmental disorder that may cause pervasive negative consequences for adults who stutter (AWS). Historically, intervention for AWS has primarily addressed speech fluency, with less focus on the covert psychosocial aspects of the disorder. The purpose of this article is to report on a feasibility trial evaluating a novel integrated intervention that combines traditional stuttering management techniques with Acceptance and Commitment Therapy (ACT) for AWS. METHOD: Twenty-nine AWS participated in the feasibility trial. All participants successfully completed a combined fluency and ACT intervention, titled the fluency and Acceptance and Commitment Therapy for Stuttering (fACTS) Program. As this was a feasibility study, no control group was included. Intervention was administered by two certified practicing speech-language pathologists, over eight 60- to 90-min sessions. RESULTS: Generalized linear mixed modeling was used to determine change from pre- to post-intervention and follow-up. Significant pre- and post-intervention improvements in self-efficacy, psychosocial functioning, and psychological flexibility were observed, along with significant reductions in observable stuttering behaviors (i.e., stuttered speech frequency). Intervention gains for all variables of interest were maintained 3 and 6 months post-intervention. CONCLUSIONS: The fACTS Program was created to be a holistic and flexible intervention to promote self-efficacy beliefs and address stuttering-related psychosocial impacts and speech fluency goals of AWS. Preliminary results indicated positive improvement in all psychosocial outcomes (i.e., self-efficacy, psychosocial impact, and psychological flexibility) and observable speech fluency following completion of the program. Future clinical trials of the fACTS Program with an included control group will further investigate the mechanisms of change for the positive effects observed.
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Terapia de Aceptación y Compromiso , Tartamudeo , Adulto , Humanos , Adolescente , Tartamudeo/terapia , Tartamudeo/psicología , Habla , AutoeficaciaRESUMEN
[This corrects the article DOI: 10.1016/j.heliyon.2019.e02390.].
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BACKGROUND: Acute invasive fungal sinusitis (AIFS) is an aggressive disease that requires prompt diagnosis and multidisciplinary treatment given its rapid progression. However, there is currently no consensus on diagnosis, prognosis, and management strategies for AIFS, with multiple modalities routinely employed. The purpose of this multi-institutional and multidisciplinary evidence-based review with recommendations (EBRR) is to thoroughly review the literature on AIFS, summarize the existing evidence, and provide recommendations on the management of AIFS. METHODS: The PubMed, EMBASE, and Cochrane databases were systematically reviewed from inception through January 2022. Studies evaluating management for orbital, non-sinonasal head and neck, and intracranial manifestations of AIFS were included. An iterative review process was utilized in accordance with EBRR guidelines. Levels of evidence and recommendations on management principles for AIFS were generated. RESULTS: A review and evaluation of published literature was performed on 12 topics surrounding AIFS (signs and symptoms, laboratory and microbiology diagnostics, endoscopy, imaging, pathology, surgery, medical therapy, management of extrasinus extension, reversing immunosuppression, and outcomes and survival). The aggregate quality of evidence was varied across reviewed domains. CONCLUSION: Based on the currently available evidence, judicious utilization of a combination of history and physical examination, laboratory and histopathologic techniques, and endoscopy provide the cornerstone for accurate diagnosis of AIFS. In addition, AIFS is optimally managed by a multidisciplinary team via a combination of surgery (including resection whenever possible), antifungal therapy, and correcting sources of immunosuppression. Higher quality (i.e., prospective) studies are needed to better define the roles of each modality and determine diagnosis and treatment algorithms.
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Infecciones Fúngicas Invasoras , Sinusitis , Humanos , Estudios Prospectivos , Infecciones Fúngicas Invasoras/diagnóstico , Enfermedad Aguda , Pronóstico , Sinusitis/diagnóstico , Sinusitis/terapia , Sinusitis/microbiologíaRESUMEN
Our laboratory focuses on the development of novel neuroprotective cationic peptides, such poly-arginine-18 (R18: 18-mer of l-arginine; net charge +18) and its d-enantiomer R18D in stroke and other brain injuries. In the clinical development of R18/R18D, their cationic property raises potential safety concerns on their non-specific effects to induce mast cell degranulation and hemolysis. To address this, we first utilised primary human cultured mast cells (HCMCs) to examine anaphylactoid effects. We also included as controls, the well-characterised neuroprotective TAT-NR2B9c peptide and the widely used heparin reversal peptide, protamine. Degranulation assay based on ß-hexosaminidase release demonstrated that R18 and R18D did not induce significant mast cell degranulation in both untreated (naïve) and IgE-sensitised HCMCs in a dose-response study to a maximum peptide concentration of 16 µM. Similarly, TAT-NR2B9c and protamine did not induce significant mast cell degranulation. To examine hemolytic effects, red blood cells (RBCs), were incubated with the peptides at a concentration range of 1-16 µM in the absence or presence of 2% plasma. Measurement of hemoglobin absorbance revealed that only R18 induced a modest, but significant degree of hemolysis at the 16 µM concentration, and only in the absence of plasma. This study addressed the potential safety concern of the application of the cationic neuroprotective peptides, especially, R18D, on anaphylactoid responses and hemolysis. The findings indicate that R18, R18D, TAT-NR2B9c and protamine are unlikely to induce histamine mediated anaphylactoid reactions or RBC hemolysis when administered intravenously to patients.
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The poly-arginine peptides R18D and R18 represent novel potential neuroprotective treatments for acute ischaemic stroke. Here we examined whether R18D and R18 had any significant effects on the thrombolytic activity of alteplase (tPA) and tenecteplase (TNK) on clots formed from whole blood in an in vitro thrombolysis plate assay. R18D and R18 were examined at concentrations of 0.25, 0.5, 1, 2, 4, 8 and 16 µM during the 1-h thrombolytic assay. We also included the well-characterised neuroprotective NA-1 peptide as a control. R18D, R18 and NA-1 all reduced tPA or TNK percentage clot lysis by 0-9.35%, 0-3.44% and 0-4.8%, respectively. R18D, R18 and NA-1 had a modest and variable effect on the lag time, increasing the time to the commencement of thrombolysis by 0-9.9 min, 0-5.53 min and 0-7.16 min, respectively. Lastly, R18 and NA-1 appeared to increase the maximal activity of the thrombolysis reaction. In addition, the in vitro anti-excitotoxic neuroprotective efficacy of R18D and R18 was not affected by pre-incubation for 1-2 h or overnight with tPA or TNK, whereas only R18D retained high anti-excitotoxic neuroprotective efficacy when pre-incubated in a synthetic trypsin (TrypLE Express). The present in vitro findings suggest that neither R18D or R18 when co-administered with the thrombolytic inducing agents tPA or TNK are likely to have a significant impact when used clinically during clot thrombolysis and confirm the superior proteolytic stability of the R18D peptide.
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Isquemia Encefálica , Accidente Cerebrovascular , Trombosis , Arginina , Fibrinolíticos/farmacología , Fibrinolíticos/uso terapéutico , Humanos , Péptidos/farmacología , Proteolisis , Accidente Cerebrovascular/tratamiento farmacológico , Tenecteplasa/farmacología , Tenecteplasa/uso terapéutico , Terapia Trombolítica , Activador de Tejido Plasminógeno/farmacología , Activador de Tejido Plasminógeno/uso terapéuticoRESUMEN
PURPOSE: We aim to study the prevalence of olfactory and taste dysfunction (OTD) in subjects residing in a Community Care Facility (CCF), a center unique to Singapore that is dedicated to isolate foreign workers with COVID-19 infection who have mild disease with minimal or no symptoms. METHODS: This is a cross-sectional study analyzing data prospectively collected from COVID-19-positive subjects who were admitted into a single-center Singapore EXPO CCF from 1st May 2020 to 1st July 2020. The following variables were collected: age, gender, ethnicity, anosmia, ageusia and acute respiratory infection (ARI) symptoms. Symptoms of anosmia and ageusia were self-declared via a mandatory questionnaire administered on admission. RESULTS: A total of 1983 subjects were included. The overall prevalence of anosmia and ageusia is 3.0% and 2.6%, respectively. 58% of anosmic subjects have co-existent ageusia and 72.6% of anosmic subjects have no concurrent sinonasal symptoms. OTD is less likely to present in subjects who are asymptomatic for ARI, compared to those symptomatic for ARI (anosmia: 2.0% versus 4.4% p = 0.002; ageusia: 1.6% versus 4.2% p < 0.001). There is a difference in the prevalence of OTD between the different ethnic groups (Indian, Chinese, Bangladeshi and Others), with Chinese and Bangladeshi reporting a higher prevalence (p < 0.043) CONCLUSION: The true prevalence of OTD in COVID-19-positive subjects may be low with aggressive screening of all subjects, including those asymptomatic for ARI.
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COVID-19 , Trastornos del Olfato , Estudios Transversales , Humanos , Trastornos del Olfato/epidemiología , Trastornos del Olfato/etiología , Prevalencia , SARS-CoV-2 , Singapur/epidemiología , Trastornos del Gusto/diagnóstico , Trastornos del Gusto/epidemiología , Trastornos del Gusto/etiologíaRESUMEN
Poly-arginine peptides R18 and R18D have previously been demonstrated to be neuroprotective in ischaemic stroke models. Here we examined the proteolytic stability and efficacy of R18 and R18D in reducing infarct core growth and preserving the ischaemic penumbra following middle cerebral artery occlusion (MCAO) in the Sprague Dawley rat. R18 (300 or 1000 nmol/kg), R18D (300 nmol/kg) or saline were administered intravenously 10 min after MCAO induced using a filament. Serial perfusion and diffusion-weighted MRI imaging was performed to measure changes in the infarct core and penumbra from time points between 45- and 225-min post-occlusion. Repeated measures analyses of infarct growth and penumbral tissue size were evaluated using generalised linear mixed models (GLMMs). R18D (300 nmol/kg) was most effective in slowing infarct core growth (46.8 mm3 reduction; p < 0.001) and preserving penumbral tissue (21.6% increase; p < 0.001), followed by R18 at the 300 nmol/kg dose (core: 29.5 mm3 reduction; p < 0.001, penumbra: 12.5% increase; p < 0.001). R18 at the 1000 nmol/kg dose had a significant impact in slowing core growth (19.5 mm3 reduction; p = 0.026), but only a modest impact on penumbral preservation (6.9% increase; p = 0.062). The in vitro anti-excitotoxic neuroprotective efficacy of R18D was also demonstrated to be unaffected when preincubated for 1-3 h or overnight, in a cell lysate prepared from dying neurons or with the proteolytic enzyme, plasmin, whereas the neuroprotective efficacy of R18 was significantly reduced after a 2-h incubation. These findings highlight the capacity of poly-arginine peptides to reduce infarct growth and preserve the ischaemic penumbra, and confirm the superior efficacy and proteolytic stability of R18D, which indicates that this peptide is likely to retain its neuroprotective properties when co-administered with alteplase during thrombolysis for acute ischaemic stroke.
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Infarto de la Arteria Cerebral Media/tratamiento farmacológico , Fármacos Neuroprotectores/uso terapéutico , Péptidos/uso terapéutico , Animales , Encéfalo/efectos de los fármacos , Células Cultivadas , Fibrinolisina/metabolismo , Masculino , Fármacos Neuroprotectores/química , Fármacos Neuroprotectores/metabolismo , Péptidos/química , Péptidos/metabolismo , Estabilidad Proteica , Ratas Sprague-Dawley , EstereoisomerismoRESUMEN
The Victorian Aboriginal Spectacles Subsidy Scheme (VASSS) aimed to improve access to visual aids and eye care for Aboriginal and Torres Strait Islander Victorians. The VASSS started in July 2010 and has operated continually since. In 2016, we explored the collaborations, planning, adaptations and performance of the VASSS over the first 6 years by reviewing and analysing service data, as well as data from semistructured interviews, focus groups and surveys. An estimated 10853 VASSS cofunded visual aids were delivered over 6 years, and the mean annual number of comprehensive eye examinations provided within services using VASSS grew 4.6-fold faster compared with the 4 years preceding the VASSS. We estimate that 16% and 19% of recipients presented with distance and near vision impairments respectively, all of which were corrected with visual aids. VASSS achievements were attained through collaborations, flexibility, trust and communication between organisations, all facilitated by funding resulting from evidence-based advocacy. Access to visual aids and eye examinations by Aboriginal Victorians has improved during the operation of the VASSS, with associated direct and indirect benefits to Aboriginal health, productivity and quality of life. The success of the VASSS may be replicable in other jurisdictions and provides lessons that may be applicable in other fields.
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Servicios de Salud del Indígena , Anteojos , Humanos , Nativos de Hawái y Otras Islas del Pacífico , Calidad de Vida , VictoriaRESUMEN
Cationic arginine-rich peptides represent a novel class of peptides being developed as neuroprotective agents for stroke and other acute and chronic neurological disorders. As a group, cationic arginine-rich peptides have a diverse range of other biological properties including the ability to traverse cell membranes, modulate immune responses, antagonise ion channel receptor function, as well as possessing cardioprotective, anti-nociceptive, anti-microbial and anti-cancer properties. A sound understanding of their safety profile is essential for the design of future clinical trials and for ensuring translational success with these compounds. At present, while many neuroprotective cationic arginine-rich peptides have been examined in preclinical animal neuroprotection studies, few have been assessed in human safety studies. Despite this, the safety of the prototypical cationic arginine-rich peptide, protamine, which has been in clinical use for over 70 years to reverse the anticoagulant effects of heparin and as an excipient in certain insulin preparations, is well established. In addition, the poly-arginine peptide R9 (ALX40-4C) was developed as an anti-human inmmunodeficiency virus therapeutic in the mid-1990s, and more recently, the neuroprotective cationic arginine-rich peptides TAT-NR2B9c (NA-1), CN-105 and RD2 are being evaluated for the treatment of ischaemic stroke, haemorrhagic stroke and Alzheimer's disease, respectively. Based on the available clinical data, cationic arginine-rich peptides as a group appear to be safe when administered at therapeutic doses by a slow intravenous infusion. While protamine, owing to its isolation from salmon milt and homology with human sperm protamine, can trigger anaphylactic and anaphylactoid reactions in a small proportion of patients previously exposed to the peptide (e.g. diabetic patients), who are allergic to fish or have undergone a vasectomy, such reactions are unlikely to be triggered in individuals exposed to non-protamine cationic arginine-rich peptides.
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Fármacos Neuroprotectores/uso terapéutico , Péptidos/uso terapéutico , Accidente Cerebrovascular/prevención & control , Humanos , Fármacos Neuroprotectores/administración & dosificación , Péptidos/administración & dosificaciónRESUMEN
Respiratory particle generation and dispersal during nasoendoscopy and swab testing is studied with high-speed video and laser light illumination. Video analysis reveals droplet formation in three manoeuvres during nasoendoscopy - sneezing, vocalization, and nasal decongestion spray. A capillary bridge of mucus can be seen when a nasoendoscope exits wet nares. No droplet formation is seen during oral and nasopharyngeal swab testing. We outline the following recommendations: pull the face mask down partially and keep the mouth covered, only allowing nasal access during nasoendoscopy; avoid nasal sprays if possible; if nasal sprays are used, procedurists should be in full personal protective equipment prior to using the spray; withdrawal of swabs and scopes should be performed in a slow and controlled fashion to reduce potential dispersion of droplets when the capillary bridge of mucus breaks up.
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Prueba de COVID-19 , Endoscopía , Moco , Cavidad Nasal , Fonación/fisiología , Estornudo/fisiología , Administración Intranasal , Humanos , Control de Infecciones , Transmisión de Enfermedad Infecciosa de Paciente a Profesional , Rociadores Nasales , Equipo de Protección PersonalRESUMEN
Recent studies have highlighted that a novel class of neuroprotective peptide, known as cationic arginine-rich peptides (CARPs), have intrinsic neuroprotective properties and are particularly effective anti-excitotoxic agents. As such, the present study investigated the mechanisms underlying the anti-excitotoxic properties of CARPs, using poly-arginine-18 (R18; 18-mer of arginine) as a representative peptide. Cortical neuronal cultures subjected to glutamic acid excitotoxicity were used to assess the effects of R18 on ionotropic glutamate receptor (iGluR)-mediated intracellular calcium influx, and its ability to reduce neuronal injury from raised intracellular calcium levels after inhibition of endoplasmic reticulum calcium uptake by thapsigargin. The results indicate that R18 significantly reduces calcium influx by suppressing iGluR overactivation, and results in preservation of mitochondrial membrane potential (ΔΨm) and ATP production, and reduced ROS generation. R18 also protected cortical neurons against thapsigargin-induced neurotoxicity, which indicates that the peptide helps maintain neuronal survival when intracellular calcium levels are elevated. Taken together, these findings provide important insight into the mechanisms of action of R18, supporting its potential application as a neuroprotective therapeutic for acute and chronic neurological disorders.
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Neuronas/metabolismo , Neuroprotección/efectos de los fármacos , Péptidos/farmacología , Receptores de Glutamato/genética , Animales , Calcio/metabolismo , Supervivencia Celular/efectos de los fármacos , Células Cultivadas , Corteza Cerebral/metabolismo , Corteza Cerebral/patología , Retículo Endoplásmico/efectos de los fármacos , Retículo Endoplásmico/metabolismo , Ácido Glutámico/química , Humanos , Mitocondrias/efectos de los fármacos , Mitocondrias/genética , Neuroprotección/genética , Fármacos Neuroprotectores/química , Fármacos Neuroprotectores/farmacología , Péptidos/química , Ratas , Receptores de Glutamato/químicaRESUMEN
BACKGROUND: Despite extensive studies, there are still no clinically available neuroprotective treatments for traumatic brain injury. OBJECTIVES: In previous studies we demonstrated beneficial treatment effects of polyarginine peptides R18 (18-mer of arginine; 300 nmol/kg) and R18D (18-mer of D-arginine; 1000 nmol/kg) in a rat model of impact-acceleration closed-head injury. METHODS: We examined the efficacy of R18D when intravenously administered at a low (100 nmol/kg) and high (1000 nmol/kg) dose, 30 minutes after a closed-head injury in male Sprague-Dawley rats. RESULTS: At postinjury day 3, treatment with R18D at the high dose significantly reduced axonal injury (Pâ¯=â¯0.044), whereas the low-dose treatment of R18D showed a trend for reduced axonal injury. Following assessment in the Barnes maze, both doses of R18D treatment appeared to improve learning and memory recovery compared with vehicle treatment at postinjury days 1 and 3, albeit not to a statistically significant level. Rotarod assessment of vestibulomotor recovery did not differ between R18D and the vehicle treatment groups. CONCLUSIONS: R18D modestly decreased axonal injury only at the highest dose used but had no significant effect on functional recovery. These findings warrant further studies with additional doses to better understand peptide pharmacodynamics and provide information to guide optimal dosing.
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There are virtually no clinically available neuroprotective drugs for the treatment of acute and chronic neurological disorders, hence there is an urgent need for the development of new neuroprotective molecules. Cationic arginine-rich peptides (CARPs) are an expanding and relatively novel class of compounds, which possess intrinsic neuroprotective properties. Intriguingly, CARPs possess a combination of biological properties unprecedented for a neuroprotective agent including the ability to traverse cell membranes and enter the CNS, antagonize calcium influx, target mitochondria, stabilize proteins, inhibit proteolytic enzymes, induce pro-survival signaling, scavenge toxic molecules, and reduce oxidative stress as well as, having a range of anti-inflammatory, analgesic, anti-microbial, and anti-cancer actions. CARPs have also been used as carrier molecules for the delivery of other putative neuroprotective agents across the blood-brain barrier and blood-spinal cord barrier. However, there is increasing evidence that the neuroprotective efficacy of many, if not all these other agents delivered using a cationic arginine-rich cell-penetrating peptide (CCPPs) carrier (e.g., TAT) may actually be mediated largely by the properties of the carrier molecule, with overall efficacy further enhanced according to the amino acid composition of the cargo peptide, in particular its arginine content. Therefore, in reviewing the neuroprotective mechanisms of action of CARPs we also consider studies using CCPPs fused to a putative neuroprotective peptide. We review the history of CARPs in neuroprotection and discuss in detail the intrinsic biological properties that may contribute to their cytoprotective effects and their usefulness as a broad-acting class of neuroprotective drugs.
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Thrombolytic therapy with recombinant tissue plasminogen activator (rtPA) in ischaemic stroke has been associated with neurotoxicity, blood brain barrier (BBB) disruption and intra-cerebral hemorrhage. To examine rtPA cellular toxicity we investigated the effects of rtPA on cell viability in neuronal, astrocyte and brain endothelial cell (bEnd.3) cultures with and without prior exposure to oxygen-glucose deprivation (OGD). In addition, the neuroprotective peptide poly-arginine-18 (R18D; 18-mer of D-arginine) was examined for its ability to reduce rtPA toxicity. Studies demonstrated that a 4- or 24-h exposure of rtPA was toxic, affecting neuronal cell viability at ≥ 2 µM, and astrocyte and bEnd.3 cells viability at ≥ 5 µM. In addition, a 4-h exposure to rtPA after a period of OGD (OGD/rtPA) exacerbated toxicity, affecting neuronal, astrocyte and bEnd.3 cell viability at rtPA concentrations as low as 0.1 µM. Treatment of cells with low concentrations of R18D (0.5 and 1 µM) reduced the toxic effects of rtPA and OGD/rtPA, while on some occasions a higher 2 µM R18D concentrations exacerbated neuronal and bEnd.3 cell toxicity in OGD/rtPA exposed cultures. In exploratory studies we also demonstrated that OGD activates matrix metalloproteinase-9 (MMP-9) release into the supernatant of astrocyte and bEnd.3 cell cultures, but not neuronal cultures, and that OGD/rtPA increases MMP-9 activation. Furthermore, R18D decreased MMP-9 activation in OGD/rtPA treated astrocyte and bEnd.3 cell cultures. In summary, the findings show that rtPA can be toxic to neural cells and that OGD exacerbates toxicity, while R18D has the capacity to reduce rtPA neural cellular toxicity and reduce MMP-9 activation in astrocytes and bEnd.3. Poly-arginine-18 peptides, which are being developed as neuroprotective therapeutics for ischaemic stroke, therefore have the additional potential of reducing cytotoxic effects associated with rtPA thrombolysis in the treatment of ischaemic stroke.
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Péptidos y Proteínas de Señalización Intracelular/farmacología , Neuronas/efectos de los fármacos , Neuronas/metabolismo , Activador de Tejido Plasminógeno/toxicidad , Animales , Animales Recién Nacidos , Supervivencia Celular/efectos de los fármacos , Supervivencia Celular/fisiología , Células Cultivadas , Relación Dosis-Respuesta a Droga , Ratones , Neuronas/patología , Ratas , Ratas Sprague-Dawley , Proteínas Recombinantes/toxicidadRESUMEN
Paediatric aortic trauma is a rare injury which can be fatal if not identified and managed appropriately. Surgical repair remains the gold-standard in moderate to severe aortic injuries. In the last decade however, endovascular treatment has gained popularity in children who have suitable vascular anatomy for intervention and are either not fit for surgery or in whom, endovascular intervention is the only alternative that will make a difference in the clinical outcome. Children pose a unique set of challenges to endovascular therapy. In this article, we aim to illustrate the different endovascular options that are available for the treatment of acute traumatic aortic injury and visceral thromboembolisation through pictorial representation. We will also demonstrate the feasibility and the limitation of this technique.
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Aorta Abdominal/lesiones , Aorta Torácica/lesiones , Procedimientos Endovasculares , Heridas no Penetrantes/cirugía , Heridas Punzantes/cirugía , Accidentes de Tránsito , Adolescente , Aorta Abdominal/cirugía , Aorta Torácica/cirugía , Niño , Preescolar , Angiografía por Tomografía Computarizada , Estudios de Factibilidad , Humanos , Angiografía por Resonancia Magnética , Masculino , Heridas no Penetrantes/diagnóstico , Heridas Punzantes/diagnósticoRESUMEN
Poly-arginine peptide-18 (R18) is neuroprotective in different rodent middle cerebral artery occlusion (MCAO) stroke models. In this study, we examined whether R18 treatment could reduce ischemic brain injury and improve functional outcome in a nonhuman primate (NHP) stroke model. A stroke was induced in male cynomolgus macaques by MCAO distal to the orbitofrontal branch of the MCA through a right pterional craniotomy, using a 5-mm titanium aneurysm clip for 90 min. R18 (1000 nmol/kg) or saline vehicle was administered intravenously 60 min after the onset of MCAO. Magnetic resonance imaging (MRI; perfusion-weighted imaging, diffusion-weighted imaging, or T2-weighted imaging) of the brain was performed 15 min, 24 h, and 28 days post-MCAO, and neurological outcome was assessed using the NHP stroke scale (NHPSS). Experimental endpoint was 28 days post-MCAO, treatments were randomized, and all procedures were performed blinded to treatment status. R18 treatment reduced infarct lesion volume by up to 65.2% and 69.7% at 24 h and 28 days poststroke, respectively. Based on NHPSS scores, R18-treated animals displayed reduced functional deficits. This study confirms the effectiveness of R18 in reducing the severity of ischemic brain injury and improving functional outcomes after stroke in a NHP model, and provides further support for its clinical development as a stroke neuroprotective therapeutic.
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Encéfalo/efectos de los fármacos , Péptidos y Proteínas de Señalización Intracelular/farmacología , Fármacos Neuroprotectores/farmacología , Recuperación de la Función/efectos de los fármacos , Accidente Cerebrovascular/patología , Animales , Encéfalo/patología , Modelos Animales de Enfermedad , Macaca fascicularis , MasculinoRESUMEN
We have previously demonstrated that Cationic Arginine-Rich Peptides (CARPs) and in particular poly-arginine-18 (R18; 18-mer of arginine) exhibit potent neuroprotective properties in both in vitro and in vivo neuronal injury models. Based on the current literature, there is a consensus that arginine residues by virtue of their positive charge and guanidinium head group is the critical element for imparting CARP neuroprotective properties and their ability to traverse cell membranes. This study examined the importance of guanidinium head groups in R18 for peptide cellular uptake, localization, and neuroprotection. This was achieved by using poly-ornithine-18 (O18; 18-mer of ornithine) as a control, which is structurally identical to R18, but possesses amino head groups rather than guanidino head groups. Epifluorescence and confocal fluorescence microscopy was used to examine the cellular uptake and localization of the FITC-conjugated R18 and O18 in primary rat cortical neurons and SH-SY5Y human neuroblastoma cell cultures. An in vitro cortical neuronal glutamic acid excitotoxicity model was used to compare the effectiveness of R18 and O18 to inhibit cell death and intracellular calcium influx, as well as caspase and calpain activation. Fluorescence imaging studies revealed cellular uptake of both FITC-R18 and FITC-O18 in neuronal and SH-SY5Y cells; however, intracellular localization of the peptides differed in neurons. Following glutamic acid excitotoxicity, only R18 was neuroprotective, prevented caspases and calpain activation, and was more effective at reducing neuronal intracellular calcium influx. Overall, this study demonstrated that for long chain cationic poly-arginine peptides, the guanidinium head groups provided by arginine residues are an essential requirement for neuroprotection but are not required for entry into neurons.