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1.
J Exp Med ; 221(7)2024 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-38829369

RESUMO

Cryptosporidium is an enteric pathogen and a prominent cause of diarrheal disease worldwide. Control of Cryptosporidium requires CD4+ T cells, but how protective CD4+ T cell responses are generated is poorly understood. Here, Cryptosporidium parasites that express MHCII-restricted model antigens were generated to understand the basis for CD4+ T cell priming and effector function. These studies revealed that parasite-specific CD4+ T cells are primed in the draining mesenteric lymph node but differentiate into Th1 cells in the gut to provide local parasite control. Although type 1 conventional dendritic cells (cDC1s) were dispensable for CD4+ T cell priming, they were required for CD4+ T cell gut homing and were a source of IL-12 at the site of infection that promoted local production of IFN-γ. Thus, cDC1s have distinct roles in shaping CD4+ T cell responses to an enteric infection: first, to promote gut homing from the mesLN, and second, to drive effector responses in the intestine.


Assuntos
Linfócitos T CD4-Positivos , Criptosporidiose , Cryptosporidium , Células Dendríticas , Camundongos Endogâmicos C57BL , Animais , Células Dendríticas/imunologia , Células Dendríticas/parasitologia , Criptosporidiose/imunologia , Criptosporidiose/parasitologia , Linfócitos T CD4-Positivos/imunologia , Linfócitos T CD4-Positivos/parasitologia , Camundongos , Cryptosporidium/imunologia , Cryptosporidium/fisiologia , Intestinos/imunologia , Intestinos/parasitologia , Interleucina-12/metabolismo , Interleucina-12/imunologia , Interferon gama/metabolismo , Interferon gama/imunologia , Células Th1/imunologia , Linfonodos/imunologia , Linfonodos/parasitologia
2.
PLoS Pathog ; 20(5): e1011820, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38718306

RESUMO

The production of IFN-γ is crucial for control of multiple enteric infections, but its impact on intestinal epithelial cells (IEC) is not well understood. Cryptosporidium parasites exclusively infect epithelial cells and the ability of interferons to activate the transcription factor STAT1 in IEC is required for parasite clearance. Here, the use of single cell RNA sequencing to profile IEC during infection revealed an increased proportion of mid-villus enterocytes during infection and induction of IFN-γ-dependent gene signatures that was comparable between uninfected and infected cells. These analyses were complemented by in vivo studies, which demonstrated that IEC expression of the IFN-γ receptor was required for parasite control. Unexpectedly, treatment of Ifng-/- mice with IFN-γ showed the IEC response to this cytokine correlates with a delayed reduction in parasite burden but did not affect parasite development. These data sets provide insight into the impact of IFN-γ on IEC and suggest a model in which IFN-γ signalling to uninfected enterocytes is important for control of Cryptosporidium.


Assuntos
Criptosporidiose , Interferon gama , Mucosa Intestinal , Camundongos Knockout , Animais , Interferon gama/metabolismo , Interferon gama/imunologia , Criptosporidiose/imunologia , Criptosporidiose/parasitologia , Camundongos , Mucosa Intestinal/parasitologia , Mucosa Intestinal/metabolismo , Mucosa Intestinal/imunologia , Cryptosporidium , Células Epiteliais/parasitologia , Células Epiteliais/metabolismo , Células Epiteliais/imunologia , Enterócitos/parasitologia , Enterócitos/metabolismo , Enterócitos/imunologia , Camundongos Endogâmicos C57BL , Receptor de Interferon gama , Fator de Transcrição STAT1/metabolismo , Receptores de Interferon/metabolismo , Receptores de Interferon/genética , Transdução de Sinais
3.
Mucosal Immunol ; 17(3): 387-401, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38508522

RESUMO

Cryptosporidium causes debilitating diarrheal disease in patients with primary and acquired defects in T cell function. However, it has been a challenge to understand how this infection generates T cell responses and how they mediate parasite control. Here, Cryptosporidium was engineered to express a parasite effector protein (MEDLE-2) that contains the major histocompatibility complex-I restricted SIINFEKL epitope which is recognized by T cell receptor transgenic OT-I(OVA-TCR-I) clusters of differentiation (CD)8+ T cells. These modified parasites induced expansion of endogenous SIINFEKL-specific and OT-I CD8+ T cells that were a source of interferon-gamma (IFN-γ) that could restrict growth of Cryptosporidium. This T cell response was dependent on the translocation of the effector and similar results were observed with another secreted parasite effector (rhoptry protein 1). Although infection and these translocated effector proteins are restricted to intestinal epithelial cells, type 1 conventional dendritic cells were required to generate CD8+ T cell responses to these model antigens. These data sets highlight Cryptosporidium effectors as potential targets of the immune system and suggest that crosstalk between enterocytes and type 1 conventional dendritic cells is crucial for CD8+ T cell responses to Cryptosporidium.


Assuntos
Linfócitos T CD8-Positivos , Criptosporidiose , Cryptosporidium , Células Dendríticas , Linfócitos T CD8-Positivos/imunologia , Células Dendríticas/imunologia , Animais , Criptosporidiose/imunologia , Camundongos , Cryptosporidium/imunologia , Interferon gama/metabolismo , Proteínas de Protozoários/metabolismo , Proteínas de Protozoários/imunologia , Antígenos de Protozoários/imunologia , Humanos , Camundongos Transgênicos , Ativação Linfocitária/imunologia , Epitopos de Linfócito T/imunologia , Camundongos Endogâmicos C57BL , Mucosa Intestinal/imunologia , Mucosa Intestinal/parasitologia , Camundongos Knockout
4.
bioRxiv ; 2023 Nov 13.
Artigo em Inglês | MEDLINE | ID: mdl-38014026

RESUMO

Cryptosporidium is an enteric pathogen that is a prominent cause of diarrheal disease. Control of this infection requires CD4+ T cells, though the processes that lead to T cell-mediated resistance have been difficult to assess. Here, Cryptosporidium parasites that express MHCII-restricted model antigens were generated to dissect the early events that influence CD4+ T cell priming and effector function. These studies highlight that parasite-specific CD4+ T cells are primed in the draining mesenteric lymph node (mesLN) and differentiate into Th1 cells in the gut, where they mediate IFN-γ-dependent control of the infection. Although type 1 conventional dendritic cells (cDC1s) were not required for initial priming of CD4+ T cells, cDC1s were required for CD4+ T cell expansion and gut homing. cDC1s were also a major source of IL-12 that was not required for priming but promoted full differentiation of CD4+ T cells and local production of IFN-γ. Together, these studies reveal distinct roles for cDC1s in shaping CD4+ T cell responses to enteric infection: first to drive early expansion in the mesLN and second to drive effector responses in the gut.

5.
bioRxiv ; 2023 Nov 16.
Artigo em Inglês | MEDLINE | ID: mdl-38014210

RESUMO

The production of IFN-γ is crucial for control of multiple enteric infections, but its impact on intestinal epithelial cells (IEC) is not well understood. Cryptosporidium parasites exclusively infect epithelial cells and the ability of interferons to activate the transcription factor STAT1 in IEC is required for parasite clearance. The use of single cell RNA sequencing to profile IEC during infection revealed induction of IFN-γ-dependent gene signatures that was comparable between uninfected and infected cells, and IEC expression of the IFN-γ receptor was required for parasite control. Unexpectedly, treatment of Ifng-/- mice with IFN-γ demonstrated the IEC response to this cytokine correlates with a delayed reduction in parasite burden but did not affect parasite development. These data sets provide insight into the impact of IFN-γ on IEC and suggest a model in which IFN-γ-mediated bystander activation of uninfected enterocytes is important for control of Cryptosporidium.

6.
bioRxiv ; 2023 Aug 18.
Artigo em Inglês | MEDLINE | ID: mdl-37645924

RESUMO

Cryptosporidium causes debilitating diarrheal disease in patients with primary and acquired defects in T cell function. However, it has been a challenge to understand how this infection generates T cell responses and how they mediate parasite control. Here, Cryptosporidium was engineered to express a parasite effector protein (MEDLE-2) that contains the MHC-I restricted SIINFEKL epitope which is recognized by TCR transgenic OT-I CD8 + T cells. These modified parasites induced expansion of endogenous SIINFEKL-specific and OT-I CD8 + T cells that were a source of IFN-γ that could restrict growth of Cryptosporidium . This T cell response was dependent on the translocation of the effector and similar results were observed with another secreted parasite effector (ROP1). Although infection and these translocated effector proteins are restricted to intestinal epithelial cells (IEC), type I dendritic cells (cDC1) were required to generate CD8 + T cell responses to these model antigens. These data sets highlight Cryptosporidium effectors as targets of the immune system and suggest that crosstalk between enterocytes and cDC1s is crucial for CD8 + T cell responses to Cryptosporidium .

7.
Eur J Orthop Surg Traumatol ; 33(7): 2959-2963, 2023 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-36917285

RESUMO

PURPOSE: Proximal fibula fractures are often associated with tibial plateau fractures, but their relationship is poorly characterized. The purpose of this study was to better define the relationship between tibial plateau injury severity and presence of associated soft tissue injuries. METHODS: A retrospective review was performed on all operatively treated tibial plateau fractures at a Level 1 trauma center over a 5-year period. Patient demographics, injury radiographs, CT scans, operative reports and follow-up were reviewed. RESULTS: Queried tibial plateau fractures from 2014 to 2019 totaled 217 fractures in 215 patients. Fifty-two percent were classified as AO/OTA 41B and 48% were AO/OTA 41C. Thirty-nine percent had an associated proximal fibula fracture. The presence of a proximal fibula fracture had significant correlation with AO/OTA 41C fractures, as compared with AO/OTA 41B fractures (chi-square, p < 0.001). Of the patients with a lateral split depression type tibial plateau fracture, the presence of a proximal fibula fracture was associated with more articular comminution, measured by number of articular fragments (mean = 4.0 vs. 2.9 articular fragments, p = 0.004). There was also a higher rate of meniscal injury in patients with proximal fibula fractures (37% vs. 20%, p = 0.003). CONCLUSIONS: There was a significant relationship between the higher energy tibial plateau fracture type (AO/OTA 41C) and the presence of an associated proximal fibula fracture. The presence of a proximal fibula fracture with a tibial plateau fracture is an indicator of a higher energy injury and a higher likelihood of meniscal injury.


Assuntos
Fraturas da Fíbula , Fraturas da Tíbia , Fraturas do Planalto Tibial , Humanos , Fraturas da Tíbia/diagnóstico por imagem , Fraturas da Tíbia/cirurgia , Fraturas da Tíbia/complicações , Estudos Retrospectivos , Radiografia
8.
J Neurochem ; 164(4): 499-511, 2023 02.
Artigo em Inglês | MEDLINE | ID: mdl-36336816

RESUMO

Obesity is one of the leading health concerns in the United States. Studies from human and rodent models suggest that inherent differences in the function of brain motivation centers, including the nucleus accumbens (NAc), contribute to overeating and thus obesity. For example, there are basal enhancements in the excitability of NAc GABAergic medium spiny neurons (MSN) and reductions in basal expression of AMPA-type glutamate receptors in obesity-prone vs obesity-resistant rats. However, very little is known about the regulation of extracellular glutamate and GABA within the NAc of these models. Here we gave obesity-prone and obesity-resistant rats stable isotope-labeled glucose (13 C6 -glucose) and used liquid chromatography mass spectrometry (LC-MS) analysis of NAc dialysate to examine the real-time incorporation of 13 C6 -glucose into glutamate, glutamine, and GABA. This novel approach allowed us to identify differences in glucose utilization for neurotransmitter production between these selectively bred lines. We found that voluntarily ingested or gastrically infused 13 C6 -glucose rapidly enters the NAc and is incorporated into 13 C2 -glutamine, 13 C2 -glutamate, and 13 C2 -GABA in both groups within minutes. However, the magnitude of increases in NAc 13 C2 -glutamine and 13 C2 -GABA were lower in obesity-prone than in obesity-resistant rats, while basal levels of glutamate were elevated. This suggested that there may be differences in the astrocytic regulation of these analytes. Thus, we next examined NAc glutamine synthetase, GAD67, and GLT-1 protein expression. Consistent with reduced 13 C2 -glutamine and 13 C2 -GABA, NAc glutamine synthetase and GLT-1 protein expression were reduced in obesity-prone vs obesity-resistant groups. Taken together, these data show that NAc glucose utilization differs dramatically between obesity-prone and obesity-resistant rats, favoring glutamate over GABA production in obesity-prone rats and that reductions in NAc astrocytic recycling of glutamate contribute to these differences. These data are discussed in light of established differences in NAc function between these models and the role of the NAc in feeding behavior.


Assuntos
Ácido Glutâmico , Núcleo Accumbens , Humanos , Ratos , Animais , Ácido Glutâmico/metabolismo , Núcleo Accumbens/metabolismo , Glutamina/metabolismo , Glutamato-Amônia Ligase/metabolismo , Obesidade/metabolismo , Ácido gama-Aminobutírico/metabolismo , Glucose/metabolismo
9.
PLoS Pathog ; 18(5): e1010003, 2022 05.
Artigo em Inglês | MEDLINE | ID: mdl-35584177

RESUMO

Cryptosporidium is a leading cause of severe diarrhea and diarrheal-related death in children worldwide. As an obligate intracellular parasite, Cryptosporidium relies on intestinal epithelial cells to provide a niche for its growth and survival, but little is known about the contributions that the infected cell makes to this relationship. Here we conducted a genome wide CRISPR/Cas9 knockout screen to discover host genes that influence Cryptosporidium parvum infection and/or host cell survival. Gene enrichment analysis indicated that the host interferon response, glycosaminoglycan (GAG) and glycosylphosphatidylinositol (GPI) anchor biosynthesis are important determinants of susceptibility to C. parvum infection and impact on the viability of host cells in the context of parasite infection. Several of these pathways are linked to parasite attachment and invasion and C-type lectins on the surface of the parasite. Evaluation of transcript and protein induction of innate interferons revealed a pronounced type III interferon response to Cryptosporidium in human cells as well as in mice. Treatment of mice with IFNλ reduced infection burden and protected immunocompromised mice from severe outcomes including death, with effects that required STAT1 signaling in the enterocyte. Initiation of this type III interferon response was dependent on sustained intracellular growth and mediated by the pattern recognition receptor TLR3. We conclude that host cell intrinsic recognition of Cryptosporidium results in IFNλ production critical to early protection against this infection.


Assuntos
Criptosporidiose , Cryptosporidium parvum , Interferons , Receptor 3 Toll-Like , Animais , Criptosporidiose/genética , Criptosporidiose/parasitologia , Cryptosporidium parvum/genética , Cryptosporidium parvum/imunologia , Diarreia , Interferons/imunologia , Camundongos , Receptor 3 Toll-Like/imunologia , Interferon lambda
10.
J Orthop Trauma ; 36(10): e388-e392, 2022 10 01.
Artigo em Inglês | MEDLINE | ID: mdl-35580330

RESUMO

OBJECTIVE: To quantify soft tissue perfusion changes in pilon fractures during staged treatment using laser-assisted indocyanine green angiography (LA-ICGA). SETTING: Level 1 trauma center. DESIGN: Prospective cohort study. PATIENTS/PARTICIPANTS: Twelve patients with 12 pilon fractures participated in the study. Seven patients had OTA/AO classification of 43-C3, 3 had 43-C2, and 2 had 43-B2. MAIN OUTCOME MEASURES: LA-ICGA was performed with the SPY fluorescence imaging platform. Analysis via ImageJ was used to generate a fractional area of perfusion (FAP) based on fluorescent intensity to objectively quantify soft tissue perfusion. Anterior, medial, and lateral measurements were performed at the time of initial external fixation (EF) application and then at the time of definitive fixation. RESULTS: FAP within the region of interest was on average 64% medially, 61% laterally, and 62% anteriorly immediately before EF placement. Immediately before definitive open reduction internal fixation, fractional region of interest perfusion was on average 86% medially, 87% laterally, and 86% anteriorly. FAP increased on average 24% medially ( P = 0.0004), 26% laterally ( P = 0.001), and 19% anteriorly ( P = 0.002) from the time of initial EF to the time of definitive open reduction and internal fixation. CONCLUSIONS: Quantitative improvement in soft tissue perfusion was identified through the course of staged surgical management in pilon fractures. LA-ICGA potentially may be used to determine appropriate timing for definitive surgical intervention based on the readiness of the soft tissue envelope. Ultimately, these findings may influence clinical outcomes with respect to choice of surgical approach, soft tissue management, surgical timing, and wound healing. LEVEL OF EVIDENCE: Diagnostic Level III. See Instructions for Authors for a complete description of levels of evidence.


Assuntos
Fraturas do Tornozelo , Fraturas da Tíbia , Angiografia , Fraturas do Tornozelo/cirurgia , Fixação Interna de Fraturas/métodos , Humanos , Verde de Indocianina , Lasers , Perfusão , Projetos Piloto , Estudos Prospectivos , Estudos Retrospectivos , Fraturas da Tíbia/diagnóstico por imagem , Fraturas da Tíbia/cirurgia , Resultado do Tratamento
11.
J Emerg Med ; 62(1): 95-100, 2022 01.
Artigo em Inglês | MEDLINE | ID: mdl-34509337

RESUMO

BACKGROUND: Diabetic ketoacidosis (DKA) has increased in prevalence in the emergency department (ED) in recent years. The complications of DKA are life threatening and necessitate rapid identification and management. Pediatric complications include cerebral edema, venous thrombosis, acute kidney injury, and severe infections including necrotizing fasciitis and mucormycosis. Rhinocerebral mucormycosis carries a high mortality rate and requires early treatment with antifungals and surgical debridement. CASE REPORT: A 16-year-old boy with no significant past medical history presented to the ED with new-onset DKA complicated by hypothermia, hyperosmolar hyperglycemic state, cerebral edema, and multifactorial shock. During a complicated pediatric intensive care unit admission, he was found to have fatal invasive rhinocerebral mucormycosis, causing internal carotid artery occlusion with evidence of both direct and hematogenous spread into his brain. WHY SHOULD AN EMERGENCY PHYSICIAN BE AWARE OF THIS?: Early identification of shock and appropriate management with intravenous fluids, vasopressors, and reversal of the underlying process is key in hypotensive children. In pediatric DKA, the emergency physician must consider cerebral edema, appropriate fluid resuscitation, and identify the likely precipitants leading to the onset of DKA. Thorough workup for potential precipitants should be initiated in the ED, searching for etiologies including infection, intoxication, insulin deficiency, inflammation, and ischemia. We must remember that pediatric patients, especially those with new DKA, are susceptible to life-threatening infection, including mucormycosis. Mucormycosis is a rare diagnosis, and management includes antifungal therapies and involvement of otorhinolaryngology.


Assuntos
Doenças das Artérias Carótidas , Diabetes Mellitus , Cetoacidose Diabética , Coma Hiperglicêmico Hiperosmolar não Cetótico , Mucormicose , Adolescente , Doenças das Artérias Carótidas/complicações , Artéria Carótida Interna , Criança , Cetoacidose Diabética/diagnóstico , Humanos , Masculino , Mucormicose/complicações , Mucormicose/diagnóstico
12.
J Emerg Med ; 60(3): 359-364, 2021 03.
Artigo em Inglês | MEDLINE | ID: mdl-33353811

RESUMO

BACKGROUND: Hydroxychloroquine (HCQ) poisoning is a life-threatening but treatable toxic ingestion. The scale of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection (COVID-19) and the controversial suggestion that HCQ is a treatment option have led to a significant increase in HCQ use. HCQ poisoning should be at the top-of-mind for emergency providers in cases of toxic ingestion. Treatment for HCQ poisoning includes sodium bicarbonate, epinephrine, and aggressive electrolyte repletion. We highlight the use of hypertonic saline and diazepam. CASE REPORT: We describe the case of a 37-year-old man who presented to the emergency department after the ingestion of approximately 16 g of HCQ tablets (initial serum concentration 4270 ng/mL). He was treated with an epinephrine infusion, hypertonic sodium chloride, high-dose diazepam, sodium bicarbonate, and aggressive potassium repletion. Persistent altered mental status necessitated intubation, and he was managed in the medical intensive care unit until his QRS widening and QTc prolongation resolved. After his mental status improved and it was confirmed that his ingestion was not with the intent to self-harm, he was discharged home with outpatient follow-up. WHY SHOULD AN EMERGENCY PHYSICIAN BE AWARE OF THIS?: For patients presenting with HCQ overdose and an unknown initial serum potassium level, high-dose diazepam and hypertonic sodium chloride should be started immediately for the patient with widened QRS. The choice of hypertonic sodium chloride instead of sodium bicarbonate is to avoid exacerbating underlying hypokalemia which may in turn potentiate unstable dysrhythmia. In addition, early intubation should be a priority in vomiting patients because both HCQ toxicity and high-dose diazepam cause profound sedation.


Assuntos
Tratamento Farmacológico da COVID-19 , Diazepam/uso terapêutico , Bloqueio Cardíaco/induzido quimicamente , Hidroxicloroquina/intoxicação , Hipnóticos e Sedativos/uso terapêutico , Síndrome do QT Longo/induzido quimicamente , Intoxicação/terapia , Solução Salina Hipertônica/uso terapêutico , Adulto , Eletrocardiografia , Serviço Hospitalar de Emergência , Bloqueio Cardíaco/terapia , Humanos , Síndrome do QT Longo/terapia , Masculino , SARS-CoV-2
13.
Games Health J ; 9(3): 182-186, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-31934790

RESUMO

Objective: Games for heath can take the form of interactive narratives, or stories in which readers have the option to make decisions about the direction of the plot. Individual differences may affect the extent to which individuals become engaged in such narratives. Materials and Methods: In two studies, we randomly assigned participants to read either a traditional linear narrative or an interactive version of the same narrative. We examined the influence of need for cognition (NFC) and transportability (the extent to which individuals tend to become immersed in narratives) on transportation, character identification, and perceived realism. Results: Transportability led to higher perceptions of realism in the interactive narrative in Study 1, but this effect was not replicated in Study 2. In Study 1, higher NFC led to greater identification in the interactive narrative; in Study 2, higher NFC led to greater transportation into the interactive narrative. Conclusion: Greater willingness to exert mental effort may lead to greater immersion in interactive narratives.


Assuntos
Cognição , Narração , Jogos de Vídeo/psicologia , Adolescente , Tomada de Decisões , Feminino , Humanos , Masculino , Interface Usuário-Computador , Adulto Jovem
14.
Clin Pract Cases Emerg Med ; 3(4): 341-344, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31763583

RESUMO

A 47-year-old schizophrenic male presented on three separate occasions with pancytopenia and sideroblastic anemia due to copper deficiency from massive zinc penny ingestion. The poisoning was treated differently on each visit: intravenous (IV) copper plus surgical decontamination and chelation with calcium disodium versenate (CaNa2EDTA); IV copper plus whole bowel irrigation; and IV copper with surgical decontamination only. Serum zinc half-lives were 80.0 hours, 233.2 hours, and 83.9 hours, respectively. Importantly, chelation with CaNa2EDTA did not significantly alter the elimination half-life. This is the first reported case of the same patient being treated on three different occasions with three different regimens for this condition.

15.
J Med Chem ; 62(22): 10402-10422, 2019 11 27.
Artigo em Inglês | MEDLINE | ID: mdl-31647659

RESUMO

Phosphoinositide-3-kinase δ (PI3Kδ) is a critical regulator of cell growth and transformation and has been explored as a therapeutic target for a range of diseases. Through the exploration of the thienopyrimidine scaffold, we have identified a ligand-efficient methylation that leads to remarkable selectivity for PI3Kδ over the closely related isoforms. Interrogation through the Free-Wilson analysis highlights the innate selectivity the thienopyrimidine scaffold has for PI3Kδ and provides a predictive model for the activity against the PI3K isoforms.


Assuntos
Fosfatidilinositol 3-Quinases/metabolismo , Inibidores de Fosfoinositídeo-3 Quinase/química , Inibidores de Fosfoinositídeo-3 Quinase/farmacologia , Relação Estrutura-Atividade , Aminas/química , Humanos , Isoenzimas/química , Isoenzimas/metabolismo , Metilação , Nitrogênio/química , Fosfatidilinositol 3-Quinases/química , Inibidores de Fosfoinositídeo-3 Quinase/síntese química , Pirimidinas/química , Albumina Sérica Humana/metabolismo
16.
Curr Pain Headache Rep ; 23(7): 52, 2019 Jul 03.
Artigo em Inglês | MEDLINE | ID: mdl-31270622

RESUMO

PURPOSE OF REVIEW: Back pain is a growing problem worldwide, incurring enormous economic costs and disability. Current treatment modalities often provide adequate relief but fail to address underlying conditions. Regenerative cellular modalities aim to restore anatomical function in degenerative conditions which may cause low back pain. Platelet-rich plasma (PRP) consists of an increased concentration of autologous platelets suspended in a small amount of plasma. PRP can be administered via injection or topically and is prepared using various techniques. RECENT FINDINGS: While a unifying mechanism of action is not well understood, biochemical and cellular changes involved in inflammation and mechanical structure have been detected in both in vitro and in vivo studies. At a higher level, PRP injection research utilizing animal models and patient data have provided insights into pain relief, chondroprotection, and factors that impact the therapy's efficacy. Recently, a small number of studies have promoted PRP injection as a relatively safe means of treating patients with degenerative disc disease who have failed other means of managing their lower back pain. PRP injections for sacroiliac joint-related pain are not an accepted or common treatment modality; the evidence for their efficacy remains to be seen outside of small RCTs and case reports. A small number of prospective trials have suggested there may be some benefit to using PRP injection in the treatment of pain or functional decline caused by facet joint arthropathy. These commonly used modalities require further study to improve quality of evidence and to investigate the safety and efficacy of PRP injections for various common causes of chronic low back.


Assuntos
Degeneração do Disco Intervertebral/terapia , Dor Lombar/terapia , Plasma Rico em Plaquetas , Articulação Zigapofisária/cirurgia , Humanos , Manejo da Dor/métodos , Estudos Prospectivos
17.
PLoS One ; 14(2): e0211572, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30742633

RESUMO

Both ecological theory and empirical evidence suggest that negative frequency dependent feedbacks structure plant communities, but integration of these findings has been limited. Here we develop a generic model of frequency dependent feedback to analyze coexistence and invasibility in random theoretical and real communities for which frequency dependence through plant-soil feedbacks (PSFs) was determined empirically. We investigated community stability and invasibility by means of mechanistic analysis of invasion conditions and numerical simulations. We found that communities fall along a spectrum of coexistence types ranging from strict pair-wise negative feedback to strict intransitive networks. Intermediate community structures characterized by partial intransitivity may feature "keystone competitors" which disproportionately influence community stability. Real communities were characterized by stronger negative feedback and higher robustness to species loss than randomly assembled communities. Partial intransitivity became increasingly likely in more diverse communities. The results presented here theoretically explain why more diverse communities are characterized by stronger negative frequency dependent feedbacks, a pattern previously encountered in observational studies. Natural communities are more likely to be maintained by strict negative plant-soil feedback than expected by chance, but our results also show that community stability often depends on partial intransitivity. These results suggest that plant-soil feedbacks can facilitate coexistence in multi-species communities, but that these feedbacks may also initiate cascading effects on community diversity following from single-species loss.


Assuntos
Ecossistema , Retroalimentação Fisiológica , Modelos Biológicos , Fenômenos Fisiológicos Vegetais , Solo , Biodiversidade , Espécies Introduzidas
18.
Ann Phys Rehabil Med ; 62(4): 225-233, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-30290282

RESUMO

Since ancient times, the aim of orthopedic surgery has been to correct limb and joint deformities, including those resulting from central nervous system lesions. Recent developments in the treatment of spasticity have led to changes in concepts and management strategies. The increase in life expectancy has increased the functional needs of patients. Orthopedic surgery, along with treatments for spasticity, improves the functional capacity of patients with neuro-orthopaedic disorders, improving their autonomy. In this paper, we describe key moments in the history of orthopedic surgery regarding the treatment of patients with central nervous system lesions, from poliomyelitis to stroke-related hemiplegia, from the limbs to the spine, and from contractures to heterotopic ossification. A synthesis of the current surgical techniques is then provided, and the importance of multidisciplinary evaluation and management is highlighted, along with indications for medical, rehabilitation and surgical treatments and their combinations. We explain why it is essential to consider patients' expectations and to set achievable goals, particularly before surgery, which is by nature irreversible. More recently, specialized surgical teams have begun to favor the use of soft-tissue techniques over bony and joint procedures, except for spinal disorders. We highlight that orthopedic surgery is no longer the end-point of treatment. For example, lengthening a contractured muscle improves the balance around a joint, improving mobility and stability but may be only part of the problem. Further medical treatment and rehabilitation, or additional surgery, are often necessary to continue to improve the function of the limb. Despite the recognized effectiveness of orthopedic surgery for neuro-orthopedic disorders, few studies have formally evaluated them. Hence, there is a need for research to provide evidence to support orthopedic surgery for treating neuro-orthopedic disorders.


Assuntos
Doenças do Sistema Nervoso Central/complicações , Espasticidade Muscular/cirurgia , Procedimentos Ortopédicos , Anormalidades Múltiplas/cirurgia , Toxinas Botulínicas Tipo A/uso terapêutico , Lesões Encefálicas Traumáticas/complicações , Paralisia Cerebral/complicações , Tomada de Decisão Clínica , Medicina Baseada em Evidências , Humanos , Espasticidade Muscular/etiologia , Espasticidade Muscular/reabilitação , Procedimentos Ortopédicos/métodos , Ossificação Heterotópica/complicações , Planejamento de Assistência ao Paciente , Poliomielite/complicações , Cuidados Pós-Operatórios , Quadriplegia/complicações , Acidente Vascular Cerebral/complicações , Transferência Tendinosa , Tenotomia
19.
Nat Ecol Evol ; 2(9): 1403-1407, 2018 09.
Artigo em Inglês | MEDLINE | ID: mdl-30061563

RESUMO

Ecological theory suggests that coexistence of many species within communities requires negative frequency-dependent feedbacks to prevent exclusion of the least fit species. For plant communities, empirical evidence of negative frequency dependence driving species coexistence and diversity patterns is rapidly accumulating, but connecting these findings to theory has been difficult as corresponding theoretical frameworks only consider small numbers of species. Here, we show how frequency-dependent feedback constrains community coexistence, regardless of the number of species and inherent fitness inequalities between them. Any interaction network can be characterized by a single community interaction coefficient, IC, which determines whether community-level feedback is positive or negative. Negative feedback is a necessary (but not sufficient) condition for persistence of the entire community. Even in cases where the coexistence equilibrium state cannot recover from perturbations, IC < 0 can enable species persistence via cyclic succession. The number of coexisting species is predicted to increase with the average strength of negative feedback. This prediction is supported by patterns of tree species diversity in more than 200,000 deciduous forest plots in the eastern United States, which can be reproduced in simulations that span the observed range of community feedback. By providing a quantitative metric for the strength of negative feedback needed for coexistence, we can now integrate theory and empirical data to test whether observed feedback-diversity correlations are strong enough to infer causality.


Assuntos
Ecossistema , Plantas , Modelos Teóricos , Solo
20.
Nanotechnology ; 29(9): 095301, 2018 Mar 02.
Artigo em Inglês | MEDLINE | ID: mdl-29320374

RESUMO

Several plasmonic compound nanohole arrays (CNAs), such as triangular nanoholes and fan-like nanoholes with multiple nanotips and nanogaps, are designed by a simple and efficient shadow sphere lithography technique by tuning the sphere mask size, the deposition and azimuthal angles, substrate temperature T S , and the number of deposition steps N. Compared with conventional circular nanohole arrays, the CNAs show more hot spots and exhibit new transmission speaks. Systematic finite-difference time-domain calculations indicate that different resonance modes excited by the various shaped and sized nanoholes are responsible for the enhanced plasmonic performances of CNAs. Compared to the CNA samples with only one circular hole in the unit cell, the Raman scattering intensity of the CNA with multiple triangular nanoholes, nanogaps, and nanotips can be enhanced up to 5-fold. These CNAs, due to the strong resonance due to the multiple structural features, are promising applications as optical filters, plasmonic sensors, and surface-enhanced spectroscopies.

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