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BACKGROUND: Aseptic lymphocyte-dominated vasculitis-associated lesions (ALVALs) are typically described in the context of metal-on-metal (MoM) hip bearings. This study explores the diagnostic utility of preoperative serum cobalt and chromium ion levels in determining the histological grade of ALVAL in revision hip and knee arthroplasty. METHODS: This was a multicenter retrospective review of 26 hips and 13 knees assessing the correlation between preoperative ion levels (mg/L (ppb)) and the histological grade of ALVAL from intraoperative specimens. The diagnostic ability of preoperative serum cobalt and chromium levels to determine high-grade ALVAL was assessed using a receiver operating characteristic (ROC) curve. RESULTS: In the knee cohort, there was a higher serum cobalt level in high-grade ALVAL cases (10.2 mg/L (ppb) versus 3.1 mg/L (ppb)) (P = .0002). The Area Under the Curve (AUC) was 1.00 (95% confidence interval (CI) 1.00 to 1.00). There was a higher serum chromium level in high-grade ALVAL cases (12.25 mg/L (ppb) versus 7.77 mg/L (ppb)) (P = .0002). The AUC was 0.806 (95% CI 0.555 to 1.00). In the hip cohort, there was a higher serum cobalt level in high-grade ALVAL cases (333.5 mg/L (ppb) versus 119.9 mg/L (ppb)) (P = .0831). The AUC was 0.619 (95% CI 0.388 to 0.849). There was a higher serum chromium level in high-grade ALVAL cases (186.4 mg/L (ppb) versus 79.3 mg/L (ppb)) (P = .183). The AUC was 0.595 (95% CI 0.365 to 0.824). CONCLUSIONS: Histologically, high-grade ALVAL has significantly higher preoperative serum cobalt and chromium ion levels in revision TKA. Preoperative serum ion levels have excellent diagnostic utility in revision TKA. Cobalt levels in revision THA have a fair diagnostic ability and chromium levels had a poor diagnostic ability.
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Artroplastia de Quadril , Artroplastia do Joelho , Prótese de Quadril , Próteses Articulares Metal-Metal , Vasculite , Humanos , Artroplastia do Joelho/efeitos adversos , Artroplastia de Quadril/efeitos adversos , Prótese de Quadril/efeitos adversos , Metais , Cobalto , Cromo , Linfócitos , Biomarcadores , Vasculite/diagnóstico , Vasculite/patologia , Desenho de Prótese , Próteses Articulares Metal-Metal/efeitos adversos , Falha de PróteseRESUMO
BACKGROUND: The management of congenital scoliosis poses a significant challenge for treating surgeons. The aim of our study was to provide insight into the long-term clinical results of spinal fusion in congenital scoliosis. METHODS: We performed a retrospective review of the scoliosis database in our institution for the period 1976 until 2002 identifying 43 patients with congenital scoliosis who underwent spinal fusion. Patient demographics, diagnosis, levels fused, and radiographs were evaluated. Patients were evaluated for unplanned return to the operating room (UPROR) via SRS 22, EQ5D-5L, and Oswestry Disability Index (ODI). RESULTS: Of the 43 patients who fulfilled the inclusion criteria, 22 patients agreed to participate, 3 patients were known to be deceased and 18 patients were lost to follow-up or declined to participate and were excluded. The mean age of the respondents was 40.7 years (range, 30 to 47 y) with a mean follow-up from index surgery of 35 years (range, 20 to 44 y). At most recent follow-up, 12 patients (54%) underwent UPROR. The mean age at diagnosis was 3.4 years (range, birth to 11.5 y), and the mean age for first surgery was 5.8 years (range, 1 to 13 y). As regards radiologic follow-up; the mean number of levels fused was 5.2 (range, 2 to 12). Thoracic fusion was performed in 17 patients (77%). The mean T1 to T12 height at index surgery and maturity was 166 mm (range, 130 to 240 mm) and 202 mm (range, 125 to 270 mm), respectively. The mean functional scores at follow-up were SRS 22: 4.5 (range, 2.4 to 5), cumulative EQ5D-5L score 7.2 (range, 5 to 15), and ODI: 8% (range, 2 to 30%). All respondents completed high school, 10 patients (45%) completed university, and 2 patients were awarded doctorates. Currently, 17 patients (77%) are in paid employment. CONCLUSIONS: This report constitutes the largest series of patients treated by spinal arthrodesis for congenital scoliosis followed into maturity. We demonstrate the thorax continues to grow after index fusion, patient-reported outcomes were satisfactory with superior educational and employment rates and unplanned return to theatre is rare in adult life. LEVEL OF EVIDENCE: Therapeutic Level IV.
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Escoliose , Fusão Vertebral , Adulto , Humanos , Pessoa de Meia-Idade , Criança , Lactente , Pré-Escolar , Adolescente , Escoliose/diagnóstico por imagem , Escoliose/cirurgia , Seguimentos , Resultado do Tratamento , Estudos Retrospectivos , Fusão Vertebral/métodosRESUMO
Common-law judges frequently claim to apply the 'always speaking' principle. But they recognise that they are not clear on what it means, with Lord Leggatt recently calling the metaphor 'enigmatic'. In this article, I seek to clarify this by showing that the 'always speaking' metaphor is associated with at least four different types of principle, each of which responds to a distinct issue (although there is a common theme: change over time). I explore the origins of the 'always speaking' metaphor, distinguish the four issues and explain how they relate. I argue that it is important to disentangle the four types of 'always speaking' principle, with a focus on distinguishing principles of dynamic (versus originalist) interpretation from principles that empower judges to strain or 'recast' legislation to deal with new developments sensibly. In doing so, I analyse and critique the judgments in the recent UK Supreme Court case of News Corp.
RESUMO
Kisspeptin (Kiss1) neurons are essential for reproduction, but their role in the control of energy balance and other homeostatic functions remains unclear. High-frequency firing of hypothalamic arcuate Kiss1 (Kiss1ARH) neurons releases kisspeptin into the median eminence, and neurokinin B (NKB) and dynorphin onto neighboring Kiss1ARH neurons to generate a slow EPSP mediated by TRPC5 channels that entrains intermittent, synchronous firing of Kiss1ARH neurons. High-frequency optogenetic stimulation of Kiss1ARH neurons also releases glutamate to excite the anorexigenic proopiomelanocortin (POMC) neurons and inhibit the orexigenic neuropeptide Y/agouti-related peptide (AgRP) neurons via metabotropic glutamate receptors. At the molecular level, the endoplasmic reticulum (ER) calcium-sensing protein stromal interaction molecule 1 (STIM1) is critically involved in the regulation of neuronal Ca2+ signaling and neuronal excitability through its interaction with plasma membrane (PM) calcium (e.g., TRPC) channels. Therefore, we hypothesized that deletion of Stim1 in Kiss1ARH neurons would increase neuronal excitability and their synchronous firing, which ultimately would affect energy homeostasis. Using optogenetics in combination with whole-cell recording and GCaMP6 imaging in slices, we discovered that deletion of Stim1 in Kiss1 neurons significantly increased the amplitude and duration of the slow EPSP and augmented synchronous [Ca2+]i oscillations in Kiss1ARH neurons. Deletion of Stim1 in Kiss1ARH neurons amplified the actions of NKB and protected ovariectomized female mice from developing obesity and glucose intolerance with high-fat dieting (HFD). Therefore, STIM1 appears to play a critical role in regulating synchronous firing of Kiss1ARH neurons, which ultimately affects the coordination between energy homeostasis and reproduction.SIGNIFICANCE STATEMENT Hypothalamic arcuate kisspeptin (Kiss1ARH) neurons are essential for stimulating the pulsatile release of gonadotropin-releasing hormone (GnRH) and maintaining fertility. However, Kiss1ARH neurons appear to be a key player in coordinating energy balance with reproduction. The regulation of calcium channels and hence calcium signaling is critically dependent on the endoplasmic reticulum (ER) calcium-sensing protein stromal interaction molecule 1 (STIM1), which interacts with the plasma membrane (PM) calcium channels. We have conditionally deleted Stim1 in Kiss1ARH neurons and found that it significantly increased the excitability of Kiss1ARH neurons and protected ovariectomized female mice from developing obesity and glucose intolerance with high-fat dieting (HFD).
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Núcleo Arqueado do Hipotálamo/metabolismo , Metabolismo Energético/fisiologia , Kisspeptinas/metabolismo , Neurônios/metabolismo , Obesidade/metabolismo , Molécula 1 de Interação Estromal/metabolismo , Animais , Sinalização do Cálcio/fisiologia , Dieta Hiperlipídica , Potenciais Pós-Sinápticos Excitadores/fisiologia , Feminino , Proteínas de Fluorescência Verde , CamundongosRESUMO
Based on previous evidence that the non-steroidal estrogen receptor modulator STX mitigates the effects of neurotoxic Amyloid-ß (Aß) in vitro, we have evaluated its neuroprotective benefits in a mouse model of Alzheimer's disease. Cohorts of 5XFAD mice, which begin to accumulate cerebral Aß at two months of age, were treated with orally-administered STX starting at 6 months of age for two months. After behavioral testing to evaluate cognitive function, biochemical and immunohistochemical assays were used to analyze key markers of mitochondrial function and synaptic integrity. Oral STX treatment attenuated Aß-associated mitochondrial toxicity and synaptic toxicity in the brain, as previously documented in cultured neurons. STX also moderately improved spatial memory in 5XFAD mice. In addition, STX reduced markers for reactive astrocytosis and microgliosis surrounding amyloid plaques, and also unexpectedly reduced overall levels of cerebral Aß in the brain. The neuroprotective effects of STX were more robust in females than in males. These results suggest that STX may have therapeutic potential in Alzheimer's Disease.
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Doença de Alzheimer , Síndromes Neurotóxicas , Masculino , Feminino , Animais , Camundongos , Doença de Alzheimer/tratamento farmacológico , Moduladores de Receptor Estrogênico/uso terapêutico , Camundongos Transgênicos , Peptídeos beta-Amiloides , Modelos Animais de Doenças , Placa Amiloide/tratamento farmacológicoRESUMO
Perioperative intravenous (IV) TA has become routine in knee and hip arthroplasty. Less evidence exists on the administration of oral TA in the post- operative period. Our study aims to identify the efficacy and safety of combined perioperative IV and post-operative oral TA on blood loss and Hemoglobin (Hb) drop compared to perioperative IV TA alone. Patients undergoing primary elective knee arthro- plasty at our institution were invited to participate in the study (n=50). A computer-generated randomisation sequence was created online (www.randomization. org), with an allocation ratio of 1:1 and a block size of 50. Group A received perioperative IV TA alone and post-operative oral TA (n= 26) and Group B received perioperative IV TA plus 48 hours additional oral placebo (n= 24). Day 3 total blood loss and Hb drop was calculated. Continuous, normally distributed data (total blood loss) was compared utilising using one-way analysis of variance with post hoc Tukey test. Continuous skewed data (Hb drop) was compared using the Kruskal-Wallis test. P <0.05 was considered statistically significant. Group A demonstrated a trend in decreased total blood loss that was close to statistical significance ( p = 0.072). No difference in Hb drop was identified between the 2 groups. Increased nausea was also observed in Group A. The administration of oral TA to post-operative knee arthroplasty patients does not improve further blood loss compared to patients receiving perioperative IV TA pre-operatively and at wound closure.
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Antifibrinolíticos , Artroplastia de Quadril , Artroplastia do Joelho , Ácido Tranexâmico , Antifibrinolíticos/uso terapêutico , Artroplastia de Quadril/efeitos adversos , Artroplastia do Joelho/efeitos adversos , Perda Sanguínea Cirúrgica/prevenção & controle , Humanos , Ácido Tranexâmico/uso terapêuticoRESUMO
PURPOSE: Transjugular intrahepatic portosystemic shunt (TIPS) procedure is an established procedure carried out by interventional radiologists to achieve portal decompression and to manage the complications of portal hypertension. The aim of this study was to evaluate the quality and readability of information available online for TIPS procedure. METHODS: Websites were identified using the search terms "TIPS procedure", "TIPSS procedure", "transjugular intrahepatic portosystemic shunt procedure", with the first 25 pages from the three most popular search engines (Google, Bing and Yahoo) being selected for evaluation with a total of 225. Each Website was grouped by authorship into one of five categories: (1) Physician, (2) Academic, (3) For-profit, (4) Non-profit (including government and public health), or (5) Other (discussion/social media). Readability of each Website was assessed using the Flesch-Reading Ease score, Flesch-Kincaid grade level, Gunning-Fog Index, Coleman-Liau and SMOG index. Quality was calculated using the DISCERN instrument, the Journal of the American Medical Association (JAMA) benchmark criteria and the presence of Health on the Net (HON) code certification. RESULTS: After disregarding duplicate and non-accessible Websites a total of 81 were included. The mean DISCERN score assessing the quality of information provided by Websites was "good" (59.3 ± 10.2) with adherence to the JAMA Benchmark being 54.3%. Websites with HON-code certification were statistically significantly higher in terms of DISCERN (p = 0.034) and JAMA scores (p = 0.003) compared to HON-code negative sites. The readability scores of Websites ranged from 10 to 12th grade across calculators. Thirty-two out of the 81 Websites were targeted towards patients (39.5%), 46 towards medical professionals (56.8%) and 3 were aimed at neither (3.7%). The medical professional aimed Websites were statistically significantly more difficulty to read across all readability formulas (all p < 0.001). CONCLUSION: While quality of online information available to patients is "good", the average readability for information on the internet for TIPS is set far above the recommended 7th-grade level. Academic Websites were of the highest quality, yet most challenging for the general public to read. These findings call for the production of high-quality and comprehensible content around TIPS procedure, where physicians can reliably direct their patients for information.
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Informação de Saúde ao Consumidor , Derivação Portossistêmica Transjugular Intra-Hepática , Benchmarking , Compreensão , Humanos , Internet , LeituraRESUMO
BACKGROUND: Trauma places a burden on healthcare services accounting for a large proportion of Emergency Department presentations. COVID-19 spread rapidly affecting over 30 million worldwide. To manage trauma presentations the Department of Trauma & Orthopaedic Surgery reorganised service delivery. AIM: To assess the impact of service reorganisation and Virtual Clinics on patients in a Regional Unit in Ireland. METHODS: A retrospective review of trauma activity following introduction of Virtual Fracture Clinics and Theatre COVID Pathways for a 10 week period in comparison with the same 2019 period. All patients underwent both nasopharyngeal and oropharyngeal swabs PCR testing prior to operations. Theatre and outpatient activity were evaluated. Clinic data were accumulated using the Integrated Patient Management System. RESULTS: Theatre Activity: 242 patients underwent surgery in our trauma unit (mean 2.98 per list) during the COVID- 19 period. 29 cases were performed in repurposed elective hospital giving a total of 271 during the 2020 study period. 371 cases were performed in the same 2019 period (mean 4.58 per list). Outpatient Activity: We noted a 25.86% fracture clinic referral reduction during the COVID 19 period compared to 2019. There was a 150.77% increase in patients managed through Trauma Assessment Clinic. 639 patients were managed through the Virtual Fracture Clinic Pathway during COVID 19 period. CONCLUSIONS: Over one in four fracture clinic patients can be managed virtually. A new dedicated Acute Fracture Unit within our institution permitted streamlining of care and social distancing. The "Non-COVID" pathway for ambulatory trauma was essential in managing the growing presentations of these injuries.
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COVID-19 , Centros de Traumatologia , Controle de Doenças Transmissíveis , Humanos , Estudos Retrospectivos , SARS-CoV-2RESUMO
The Internet is utilized now more than ever to research medical conditions and treatments by patients and physicians alike. The aim of this study was to evaluate the quality and readability of information available online for plantar fasciitis. Web sites were identified using the search term "plantar fasciitis." The first 25 Web sites from 5 different search engines gave a total of 125 being evaluated. Readability of each Web site was assessed using the Flesch Reading Ease score, the Flesch-Kincaid grade level, and the Gunning Fog Index. Quality was assessed using the DISCERN instrument (www.discern.org.uk) and the Journal of the American Medical Association (JAMA) benchmark criteria. The presence of Health on the Net (HON) code certification was also assessed. The authorship of each Web site was categorized into 1 of 5 categories (Physician, Academic, Commercial, Allied health or Other eg, blogs). A total of 83 Web site pages were evaluated with the majority of the web sites being authored by physicians (32.53%) and blogs (25.30%). Only 24 Web sites were HON certified (28.91%). Physician and Academic Web sites were the most credible sources, with the highest mean DISCERN (p = .00001) and JAMA (p = .0278.) scores, respectively. These Web sites were also the most difficult to read according to the readability score testing. The information available on the Internet pertaining to plantar fasciitis is highly variable and provides moderate quality information about treatment choices. Given this variability in quality, health care providers should direct patients to known sources of reliable, readable online information.
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Compreensão , Fasciíte Plantar , Fasciíte Plantar/terapia , Humanos , Internet , Estados UnidosRESUMO
When it comes to obesity, men exhibit a higher incidence of metabolic syndrome than women in early adult life, but this sex advantage wanes in postmenopausal women. A key diagnostic of the metabolic syndrome is insulin resistance in both peripheral tissues and brain, especially in the hypothalamus. Since the anorexigenic hormone 17ß-estradiol (E2) regulates food intake in part by inhibiting the excitability of the hypothalamic neuropeptide Y/agouti-related peptide (NPY/AgRP) neurons, we hypothesized that E2 would protect against insulin resistance in NPY/AgRP neurons with diet-induced obesity (DIO). Therefore, we did whole-cell recordings and single cell quantitative polymerase chain reaction in arcuate NPYGFP neurons from both female and male mice to test the efficacy of insulin with DIO. The resting membrane potential and input resistance of NPY/AgRP neurons were significantly increased in DIO versus control-diet fed males. Most notably, the efficacy of insulin to activate KATP channels in NPY/AgRP neurons was significantly attenuated, although the KATP channel opener diazoxide was fully effective in NPY/AgRP neurons from DIO males, indicating that the KATP channels were expressed and functional. In contrast, insulin was fully efficacious to activate KATP channels in DIO females, and the response was reversed by the KATP channel blocker tolbutamide. However, the ability of insulin to activate KATP channels was abrogated with ovariectomy but fully restored with E2 replacement. Insulin resistance in obese males was likely mediated by an increase in suppressor of cytokine signaling-3 (SOCS-3), protein tyrosine phosphatase B (PTP1B) and T-cell protein tyrosine phosphatase (TCPTP) activity, since the expression of all 3 mRNAs were upregulated in the obese males but not in females. As proof of principle, pre-incubation of hypothalamic slices from DIO males with the PTP1B/TCPTP inhibitor CX08005 completely rescued the effects of insulin. Therefore, E2 protects NPY/AgRP neurons in females against insulin resistance through, at least in part, attenuating phosphatase activity. The neuroprotective effects of E2 may explain sex differences in the expression of metabolic syndrome that disappears with the loss of E2 in aging.
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Proteína Relacionada com Agouti/metabolismo , Estradiol/metabolismo , Resistência à Insulina/fisiologia , Neurônios/fisiologia , Neuropeptídeo Y/metabolismo , Obesidade/metabolismo , Animais , Feminino , Masculino , Camundongos , Camundongos Transgênicos , Neurônios/metabolismo , Técnicas de Patch-Clamp , Caracteres SexuaisRESUMO
Mammalian reproductive function depends upon a neuroendocrine circuit that evokes the pulsatile release of gonadotropin hormones (luteinizing hormone and follicle-stimulating hormone) from the pituitary. This reproductive circuit is sensitive to metabolic perturbations. When challenged with starvation, insufficient energy reserves attenuate gonadotropin release, leading to infertility. The reproductive neuroendocrine circuit is well established, composed of two populations of kisspeptin-expressing neurons (located in the anteroventral periventricular hypothalamus, Kiss1AVPV, and arcuate hypothalamus, Kiss1ARH), which drive the pulsatile activity of gonadotropin-releasing hormone (GnRH) neurons. The reproductive axis is primarily regulated by gonadal steroid and circadian cues, but the starvation-sensitive input that inhibits this circuit during negative energy balance remains controversial. Agouti-related peptide (AgRP)-expressing neurons are activated during starvation and have been implicated in leptin-associated infertility. To test whether these neurons relay information to the reproductive circuit, we used AgRP-neuron ablation and optogenetics to explore connectivity in acute slice preparations. Stimulation of AgRP fibers revealed direct, inhibitory synaptic connections with Kiss1ARH and Kiss1AVPV neurons. In agreement with this finding, Kiss1ARH neurons received less presynaptic inhibition in the absence of AgRP neurons (neonatal toxin-induced ablation). To determine whether enhancing the activity of AgRP neurons is sufficient to attenuate fertility in vivo, we artificially activated them over a sustained period and monitored fertility. Chemogenetic activation with clozapine N-oxide resulted in delayed estrous cycles and decreased fertility. These findings are consistent with the idea that, during metabolic deficiency, AgRP signaling contributes to infertility by inhibiting Kiss1 neurons.
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Proteína Relacionada com Agouti/genética , Fertilidade/genética , Hipotálamo/metabolismo , Kisspeptinas/genética , Neurônios/metabolismo , Inanição/genética , Proteína Relacionada com Agouti/deficiência , Animais , Relógios Circadianos/efeitos dos fármacos , Relógios Circadianos/fisiologia , Clozapina/análogos & derivados , Clozapina/farmacologia , Ciclo Estral/efeitos dos fármacos , Ciclo Estral/fisiologia , Feminino , Fertilidade/efeitos dos fármacos , Regulação da Expressão Gênica , Hormônio Liberador de Gonadotropina/genética , Hormônio Liberador de Gonadotropina/metabolismo , Hipotálamo/efeitos dos fármacos , Kisspeptinas/metabolismo , Leptina/genética , Leptina/metabolismo , Hormônio Luteinizante/genética , Hormônio Luteinizante/metabolismo , Masculino , Camundongos , Camundongos Transgênicos , Neurônios/citologia , Neurônios/efeitos dos fármacos , Optogenética , Reprodução/efeitos dos fármacos , Reprodução/genética , Transdução de Sinais , Técnicas EstereotáxicasRESUMO
2-Arachidonoylglycerol (2-AG) is acting as a full agonist of cannabinoid receptor 1 and 2. Direct manipulation of 2-AG levels is a challenging task. The amphiphilic properties and the instability of 2-AG in aqueous media complicate its use as a drug-like molecule. Additionally, inhibition of the protein machinery that regulates 2-AG levels may also affect other monoacylglycerols. Therefore, we developed a novel method to elevate 2-AG levels with a flash of light. The resulting tool is a photoactivatable "caged" 2-arachidonoylglycerol (cg2-AG) allowing for the rapid photorelease of the signaling lipid in live cells. We characterized the mechanism of uncaging and the effect of 2-AG on the regulation of the ß-cell signaling network. After uncaging of 2-AG, we monitored calcium levels, CB1-GIRK channel coupling, and CB1-mediated inhibition of adenylate cyclase and protein kinase A activity.
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Ácidos Araquidônicos/metabolismo , Endocanabinoides/metabolismo , Glicerídeos/metabolismo , Luz , Animais , Linhagem Celular , Sobrevivência Celular , CamundongosRESUMO
All of the canonical transient receptor potential channels (TRPC) with the exception of TRPC 2 are expressed in hypothalamic neurons and are involved in multiple homeostatic functions. Although the metabotropic glutamate receptors have been shown to be coupled to TRPC channel activation in cortical and sub-cortical brain regions, in the hypothalamus multiple amine and peptidergic G protein-coupled receptors (GPCRs) and growth factor/cytokine receptors are linked to activation of TRPC channels that are vital for reproduction, temperature regulation, arousal and energy homeostasis. In addition to the neurotransmitters, circulating hormones like insulin and leptin through their cognate receptors activate TRPC channels in POMC neurons. Many of the post-synaptic effects of the neurotransmitters and hormones are regulated in different physiological states by expression of TRPC channels in the post-synaptic neurons. Therefore, TRPC channels are key targets not only for neurotransmitters but circulating hormones in their vital role to control multiple hypothalamic functions, which is the focus of this review.
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Hormônio Liberador de Gonadotropina/metabolismo , Hipotálamo/metabolismo , Insulina/metabolismo , Peptídeos e Proteínas de Sinalização Intercelular/metabolismo , Neurônios/metabolismo , Orexinas/metabolismo , Pró-Opiomelanocortina/metabolismo , Receptores Acoplados a Proteínas G/metabolismo , Canais de Cátion TRPC/metabolismo , Animais , HumanosRESUMO
Contribution to Special Issue on Fast effects of steroids. There is now compelling evidence for membrane-associated estrogen receptors in hypothalamic neurons that are critical for the hypothalamic control of homeostatic functions. It has been known for some time that estradiol (E2) can rapidly alter hypothalamic neuronal activity within seconds, indicating that some cellular effects can occur via membrane initiated events. However, our understanding of how E2 signals via membrane-associated receptors and how these signals impact physiological functions is only just emerging. Thus, E2 can affect second messenger systems including calcium mobilization and a plethora of kinases to alter cell excitability and even gene transcription in hypothalamic neurons. One population of hypothalamic neurons, the anorexigenic proopiomelanocortin (POMC) neurons, has long been considered to be a target of E2's actions based on gene (Pomc) expression studies. However, we now know that E2 can rapidly alter POMC neuronal activity within seconds and activate several intracellular signaling cascades that ultimately affect gene expression, actions which are critical for maintaining sensitivity to insulin in metabolically stressed states. E2 also affects the orexigenic Neuropeptide Y/Agouti-related Peptide (NPY/AgRP) neurons in similarly rapid but antagonistic manner. Therefore, this review will summarize our current state of knowledge of how E2 signals via rapid membrane-initiated and intracellular signaling cascades in POMC and NPY/AgRP neurons to regulate energy homeostasis.
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Regulação do Apetite/efeitos dos fármacos , Estradiol/farmacologia , Hipotálamo/efeitos dos fármacos , Neurônios/efeitos dos fármacos , Proteína Relacionada com Agouti , Animais , Anorexia/metabolismo , Regulação do Apetite/fisiologia , Homeostase/efeitos dos fármacos , Humanos , Hipotálamo/fisiologia , Neurônios/fisiologia , Neuropeptídeo Y/metabolismo , Pró-Opiomelanocortina/metabolismo , Transdução de Sinais/efeitos dos fármacosRESUMO
Estradiol rapidly regulates the activity of arcuate nucleus (ARH) proopiomelanocortin (POMC) neurons that project to the medial preoptic nucleus (MPN) to regulate lordosis. Orphanin FQ/nociceptin (OFQ/N) acts via opioid receptor-like (ORL)-1 receptors to inhibit these POMC neurons. Therefore, we tested the hypothesis that estradiol excites POMC neurons by rapidly attenuating inhibitory ORL-1 signaling in these cells. Hypothalamic slices through the ARH were prepared from ovariectomized rats injected with Fluorogold into the MPN. Electrophysiological recordings were generated in ARH neurons held at or near -60 mV, and neuronal phenotype was determined post hoc by immunohistofluorescence. OFQ/N application induced robust outward currents and hyperpolarizations via G protein-gated, inwardly rectifying K+ (GIRK) channels that were attenuated by pretreatment with either 17-ß estradiol (E2) or E2 conjugated to bovine serum albumin. This was blocked by the estrogen receptor (ER) antagonist ICI 182,780 and mimicked by the Gq-coupled membrane ER (Gq-mER) ligand STX and the ERα agonist PPT. Inhibiting phosphatidylinositol-3-kinase (PI3K) blocked the estrogenic attenuation of ORL-1/GIRK currents. Antagonizing either phospholipase C (PLC), protein kinase C (PKC), protein kinase A (PKA) or neuronal nitric oxide synthase (nNOS) also abrogated E2 inhibition of ORL-1/GIRK currents, whereas activation of PKC, PKA, protein kinase B (Akt) and nNOS substrate L-arginine all attenuated the OFQ/N response. This was observed in 92 MPN-projecting, POMC-positive ARH neurons. Thus, ORL-1 receptor-mediated inhibition of POMC neurons is rapidly and negatively modulated by E2, an effect which is stereoselective and membrane initiated via Gq-mER and ERα activation that signals through PLC, PKC, PKA, PI3K and nNOS.
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Estradiol/farmacologia , Estrogênios/farmacologia , Neurônios/efeitos dos fármacos , Neurônios/metabolismo , Pró-Opiomelanocortina/metabolismo , Receptores Opioides/metabolismo , Animais , Interações Medicamentosas , Inibidores Enzimáticos/farmacologia , Estrenos/farmacologia , Feminino , Hipotálamo/citologia , Técnicas In Vitro , Potenciais da Membrana/efeitos dos fármacos , Peptídeos Opioides/farmacologia , Ovariectomia , Piperidinas/farmacologia , Pirrolidinonas/farmacologia , Ratos , Ratos Long-Evans , Transdução de Sinais/efeitos dos fármacos , Bloqueadores dos Canais de Sódio/farmacologia , Estilbamidinas/farmacocinética , Tetrodotoxina/farmacologia , Receptor de Nociceptina , NociceptinaRESUMO
BACKGROUND: Direct to consumer (DTC) advertising, targeting the public over the physician, is an increasingly pervasive presence in medical clinics. It is trending toward a format of online interaction rather than that of traditional print and television advertising. METHODS: We analyze patient-focused Web pages from the top 5 companies supplying prostheses for total hip arthroplasties, comparing them to the top 10 independent medical websites. Quantitative comparison is performed using the Journal of American Medical Association benchmark and DISCERN criteria, and for comparative readability, we use the Flesch-Kincaid grade level, the Flesch reading ease, and the Gunning fog index. Content is analyzed for information on type of surgery and surgical approach. RESULTS: There is a statistically significant difference between the independent and DTC websites in both the mean DISCERN score (independent 74.6, standard deviation [SD] = 4.77; DTC 32.2, SD = 10.28; P = .0022) and the mean Journal of American Medical Association score (Independent 3.45, SD = 0.49; DTC 1.9, SD = 0.74; P = .004). The difference between the readability scores is not statistically significantly. The commercial content is found to be heavily biased in favor of the direct anterior approach and minimally invasive surgical techniques. CONCLUSION: We demonstrate that the quality of information on commercial websites is inferior to that of the independent sites. The advocacy of surgical approaches by industry to the patient group is a concern. This study underlines the importance of future regulation of commercial patient education Web pages.
Assuntos
Publicidade Direta ao Consumidor , Prótese de Quadril , Artroplastia de Quadril , Viés , Compreensão , Humanos , Internet , LeituraRESUMO
Parkinson's disease (PD) is a neurodegenerative disorder characterised by the progressive loss of midbrain dopaminergic neurons, which causes motor impairments. Current treatments involve dopamine replacement to address the disease symptoms rather than its cause. Factors that promote the survival of dopaminergic neurons have been proposed as novel therapies for PD. Several dopaminergic neurotrophic factors (NTFs) have been examined for their ability to protect and/or restore degenerating dopaminergic neurons, both in animal models and in clinical trials. These include glial cell line-derived neurotrophic factor, neurturin, cerebral dopamine neurotrophic factor and growth/differentiation factor 5. Delivery of these NTFs via injection or infusion to the brain raises several practical problems. A new delivery approach for NTFs involves the use of recombinant viral vectors to enable long-term expression of these factors in brain cells. Vectors used include those based on adenoviruses, adeno-associated viruses and lentiviruses. Here we review progress to date on the potential of each of these four NTFs as novel therapeutic strategies for PD, as well as the challenges that have arisen, from pre-clinical analysis to clinical trials. We conclude by discussing recently-developed approaches to optimise the delivery of NTF-carrying viral vectors to the brain.
Assuntos
Adenoviridae/genética , Dependovirus/genética , Vetores Genéticos/genética , Lentivirus/genética , Fatores de Crescimento Neural/genética , Fatores de Crescimento Neural/metabolismo , Doença de Parkinson/genética , Doença de Parkinson/terapia , Animais , Dopamina/metabolismo , Neurônios Dopaminérgicos/metabolismo , Neurônios Dopaminérgicos/patologia , Terapia Genética , HumanosRESUMO
Kisspeptin is a neuropeptide that signals via a Gαq-coupled receptor, GPR54, in gonadotropin-releasing hormone (GnRH) neurons and is essential for pubertal maturation and fertility. Kisspeptin depolarizes and excites GnRH neurons primarily through the activation of canonical transient receptor potential (TRPC) channels and the inhibition of K+ channels. The gonadal steroid 17ß-estradiol (E2) upregulates not only kisspeptin (Kiss1) mRNA but also increases the excitability of the rostral forebrain Kiss1 neurons. In addition, a primary postsynaptic action of E2 on GnRH neurons is to upregulate the expression of channel transcripts that orchestrate the downstream signaling of kisspeptin in GnRH neurons. These include not only TRPC4 channels but also low-voltage-activated T-type calcium channels and high-voltage-activated L-, N- and R-type calcium channel transcripts. Moreover, E2 has direct membrane-initiated actions to alter the excitability of GnRH neurons by enhancing ATP-sensitive potassium channel activity, which is critical for maintaining GnRH neurons in a hyperpolarized state for the recruitment of T-type calcium channels that are important for burst firing. Therefore, E2 modulates the excitability of GnRH neurons as well as of Kiss1 neurons by altering the expression and/or function of ion channels; moreover, kisspeptin provides critical excitatory input to GnRH neurons to facilitate burst firing activity and peptide release.
Assuntos
Encéfalo/metabolismo , Estradiol/metabolismo , Hormônio Liberador de Gonadotropina/metabolismo , Kisspeptinas/metabolismo , Neurônios/metabolismo , Potenciais de Ação , Animais , HumanosRESUMO
BACKGROUND: The impact of bronchiectasis on sedentary behaviour and physical activity is unknown. It is important to explore this to identify the need for physical activity interventions and how to tailor interventions to this patient population. We aimed to explore the patterns and correlates of sedentary behaviour and physical activity in bronchiectasis. METHODS: Physical activity was assessed in 63 patients with bronchiectasis using an ActiGraph GT3X+ accelerometer over seven days. Patients completed: questionnaires on health-related quality-of-life and attitudes to physical activity (questions based on an adaption of the transtheoretical model (TTM) of behaviour change); spirometry; and the modified shuttle test (MST). Multiple linear regression analysis using forward selection based on likelihood ratio statistics explored the correlates of sedentary behaviour and physical activity dimensions. Between-group analysis using independent sample t-tests were used to explore differences for selected variables. RESULTS: Fifty-five patients had complete datasets. Average daily time, mean(standard deviation) spent in sedentary behaviour was 634(77)mins, light-lifestyle physical activity was 207(63)mins and moderate-vigorous physical activity (MVPA) was 25(20)mins. Only 11% of patients met recommended guidelines. Forced expiratory volume in one-second percentage predicted (FEV1% predicted) and disease severity were not correlates of sedentary behaviour or physical activity. For sedentary behaviour, decisional balance 'pros' score was the only correlate. Performance on the MST was the strongest correlate of physical activity. In addition to the MST, there were other important correlate variables for MVPA accumulated in ≥10-minute bouts (QOL-B Social Functioning) and for activity energy expenditure (Body Mass Index and QOL-B Respiratory Symptoms). CONCLUSIONS: Patients with bronchiectasis demonstrated a largely inactive lifestyle and few met the recommended physical activity guidelines. Exercise capacity was the strongest correlate of physical activity, and dimensions of the QOL-B were also important. FEV1% predicted and disease severity were not correlates of sedentary behaviour or physical activity. The inclusion of a range of physical activity dimensions could facilitate in-depth exploration of patterns of physical activity. This study demonstrates the need for interventions targeted at reducing sedentary behaviour and increasing physical activity, and provides information to tailor interventions to the bronchiectasis population. TRIAL REGISTRATION: NCT01569009 ("Physical Activity in Bronchiectasis").
Assuntos
Atitude Frente a Saúde , Bronquiectasia/fisiopatologia , Atividade Motora , Qualidade de Vida , Comportamento Sedentário , Acelerometria , Idoso , Índice de Massa Corporal , Estudos Transversais , Metabolismo Energético , Teste de Esforço , Feminino , Volume Expiratório Forçado , Humanos , Funções Verossimilhança , Modelos Lineares , Masculino , Pessoa de Meia-Idade , Motivação , Autoeficácia , Índice de Gravidade de Doença , Espirometria , Inquéritos e QuestionáriosRESUMO
Recent molecular biological and electrophysiological studies have identified multiple transient receptor potential (TRP) channels in hypothalamic neurons as critical modulators of homeostatic functions. In particular, the canonical transient receptor potential channels (TRPCs) are expressed in hypothalamic neurons that are vital for the control of fertility and energy homeostasis. Classical neurotransmitters such as serotonin and glutamate and peptide neurotransmitters such as kisspeptin, neurokinin B and pituitary adenylyl cyclase-activating polypeptide signal through their cognate G protein-coupled receptors to activate TPRC 4, 5 channels, which are essentially ligand-gated calcium channels. In addition to neurotransmitters, circulating hormones like insulin and leptin signal through insulin receptor (InsR) and leptin receptor (LRb), respectively, to activate TRPC 5 channels in hypothalamic arcuate nucleus pro-opiomelanocortin (POMC) and kisspeptin (arcuate Kiss1 [Kiss1ARH]) neurons to have profound physiological (excitatory) effects. Besides its overt depolarizing effects, TRPC channels conduct calcium ions into the cytoplasm, which has a plethora of downstream effects. Moreover, not only the expression of Trpc5 mRNA but also the coupling of receptors to TRPC 5 channel opening are regulated in different physiological states. In particular, the mRNA expression of Trpc5 is highly regulated in kisspeptin neurons by circulating estrogens, which ultimately dictates the firing pattern of kisspeptin neurons. In obesity states, InsRs are "uncoupled" from opening TRPC 5 channels in POMC neurons, rendering them less excitable. Therefore, in this review, we will focus on the critical role of TRPC 5 channels in regulating the excitability of Kiss1ARH and POMC neurons in different physiological and pathological states.