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1.
Expert Rev Neurother ; 23(9): 819-834, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37585269

RESUMO

INTRODUCTION: Narcolepsy is an under-recognized, rare neurologic disorder of hypersomnolence that is associated with increased mortality and medical and psychiatric co-morbidities. Narcolepsy exerts a substantial economic burden on patients and society. There is currently no cure, and life-long symptomatic therapy is needed. Available drugs do not modify the disease course. AREAS COVERED: This manuscript provides an overview of narcolepsy symptoms, diagnosis, pathophysiology, current pharmacotherapies, and emerging treatments. Gaps and unresolved issues in diagnosis and management of narcolepsy are discussed to answer whether pharmacological options are the way forward. EXPERT OPINION: Diagnostic criteria for narcolepsy (ICSD-3) need revision and greater clarity. Improved recognition of cataplexy and other symptoms through educational outreach, new biomarkers, improved test scoring through artificial intelligence algorithms, and use of machine learning may facilitate earlier diagnosis and treatment. Pharmacological options need improved symptomatic therapy in addition to targeted therapies that address the loss of hypocretin signaling. Optimal narcolepsy care also needs a better understanding of the pathophysiology, recognition of the different phenotypes in narcolepsy, identification of at-risk individuals and early recognition of symptoms, better diagnostic tools, and a database for research and disease monitoring of treatment, side-effects, and comorbidities.


Assuntos
Cataplexia , Distúrbios do Sono por Sonolência Excessiva , Narcolepsia , Doenças do Sistema Nervoso , Humanos , Inteligência Artificial , Narcolepsia/diagnóstico , Narcolepsia/tratamento farmacológico , Cataplexia/diagnóstico , Cataplexia/tratamento farmacológico , Cataplexia/genética , Distúrbios do Sono por Sonolência Excessiva/complicações , Distúrbios do Sono por Sonolência Excessiva/diagnóstico , Doenças do Sistema Nervoso/complicações
2.
Expert Opin Pharmacother ; 24(8): 875-885, 2023 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-37060579

RESUMO

INTRODUCTION: Lower-sodium oxybate (LXB) is a novel formulation that is approved by the US Food and Drug Administration (FDA) to treat cataplexy and excessive daytime sleepiness (EDS) in adult patients and children ≥7 years with narcolepsy. LXB contains 92% less sodium than sodium oxybate (SXB), which adds 550-1640 mg of sodium/day at usual doses of 3-9 g/day. The FDA has declared LXB to be clinically superior to SXB due to greater safety by reducing the chronic sodium load. Narcolepsy patients have high comorbidities for hypertension and cardiovascular disease conditions, which can be adversely affected by high sodium intake. AREAS COVERED: This drug review discusses narcolepsy, current and upcoming pharmacotherapy, and LXB chemistry, pharmacodynamics, pharmacokinetics, and metabolism. Published results from LXB's phase 1 studies, a phase 3 study, and two post-marketing studies are reviewed. Databases searched included PubMed, Google Scholar, Lexi-Comp, Scopus, Science, and Ovid. EXPERT OPINION: LXB is efficacious in treating daytime sleepiness and cataplexy in adults and children ≥7 years with narcolepsy. Using LXB instead of SXB formulations may benefit narcolepsy patients with cardiovascular comorbidities and hypertension, but long-term studies are needed to prove it.


Assuntos
Cataplexia , Distúrbios do Sono por Sonolência Excessiva , Hipertensão , Narcolepsia , Oxibato de Sódio , Adulto , Criança , Humanos , Cataplexia/tratamento farmacológico , Oxibato de Sódio/efeitos adversos , Cálcio/uso terapêutico , Magnésio/uso terapêutico , Sódio/uso terapêutico , Potássio , Narcolepsia/tratamento farmacológico , Distúrbios do Sono por Sonolência Excessiva/complicações , Distúrbios do Sono por Sonolência Excessiva/tratamento farmacológico , Hipertensão/tratamento farmacológico , Hipertensão/complicações
3.
Neurosci Biobehav Rev ; 145: 105037, 2023 02.
Artigo em Inglês | MEDLINE | ID: mdl-36621585

RESUMO

The benefits gained by young animals engaging in play fighting have been a subject of conjecture for over a hundred years. Progress in understanding the behavioral development of play fighting and the underlying neurobiology of laboratory rats has produced a coherent model that sheds light on this matter. Depriving rats of typical peer-peer play experience during the juvenile period leads to adults with socio-cognitive deficiencies and these are correlated with physiological and anatomical changes to the neurons of the prefrontal cortex, especially the medial prefrontal cortex. Detailed analysis of juvenile peer play has shown that using the abilities needed to ensure that play fighting is reciprocal is critical for attaining these benefits. Therefore, unlike that which was posited by many earlier hypotheses, play fighting does not train specific motor actions, but rather, improves a skill set that can be applied in many different social and non-social contexts. There are still gaps in the rat model that need to be understood, but the model is well-enough developed to provide a framework for broader comparative studies of mammals from diverse lineages that engage in play fighting.


Assuntos
Encéfalo , Jogos e Brinquedos , Ratos , Animais , Córtex Pré-Frontal/fisiologia , Neurônios , Comportamento Social , Mamíferos
5.
Int J Numer Method Biomed Eng ; 38(9): e3617, 2022 09.
Artigo em Inglês | MEDLINE | ID: mdl-35560814

RESUMO

Most researchers have performed finite element (FE) analysis of the human forearm fracture by exploring the strength and load transmission of the bones. However, few studies concentrated a complete simulation of the whole forearm complex including ligaments. This paper aims to investigate the load transmission through the bones, contact stress at the joints and strain in the ligaments by using an elaborate FE model, further validating the fracture condition for human forearm. The interosseous ligament was separated into three regions based on the distance to the proximal and distal ends. The FE simulation results were slightly more or less than a previous experimental data in the literature, but generally provided a close approximation of the bone and ligament behaviors. Compared with the experiment results under different loading conditions, maximum contact stress at the proximal radio ulnar joint (PRUJ) and distal radio ulnar joint (DRUJ) of the simulations was higher with an average of 13.4%, and peak strain in the interosseous ligament (IOL) was lower with an average of 11.0%. Under 10 kg load, the maximum stress in the radius (2.25 MPa) was less than double the value in the ulna (1.43 MPa). Finally, the FE model has been validated with the onset and location of the Colles' fracture in the literature. This study will provide a great benefit in terms of surgical and medical applications related to forearm fracture that require an extensive knowledge of the behavior of the bones and ligaments under various loading conditions.


Assuntos
Antebraço , Ulna , Fenômenos Biomecânicos , Análise de Elementos Finitos , Humanos , Rádio (Anatomia)
6.
Am J Ophthalmol Case Rep ; 25: 101291, 2022 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-35146187

RESUMO

PURPOSE: The XEN45 gel stent implant (Allergen, CA, USA) is one of many micro-invasive surgical options available to glaucomatologists. Our case series describes the presentation, treatment, and possible risk factors of XEN45 gel stent related endophthalmitis. OBSERVATIONS: A 71 year old Chinese man and a 88 year old Caucasian woman underwent XEN45 gel stent implantation for primary open angle glaucoma. They presented with endophthalmitis at 7 and 4 months post-surgery respectively. The first patient had stent exposure with blebitis while the second patient did not show any signs of conjunctival defect, stent exposure, bleb leak nor blebitis. Both patients were treated immediately with intravitreal, topical and systemic antibiotics, followed by early vitrectomy. The implant was removed in the first, but not in the second patient. Vitreous cultures grew Streptococcus Viridans in the first patient and Haemophilus influenzae in the other. Unfortunately, the first patient eventually sustained a total retinal detachment requiring surgery and did not recover his vision. The second patient however, recovered with a good Snellen's visual acuity of 6/9 and maintenance of good intraocular pressure and bleb formation. CONCLUSIONS: Exogenous endophthalmitis related to XEN45 gel stent implantation is a rare but devastating complication. The risks factors identified were multiple post-operative procedures, bleb exposure, conjunctival defect, use of antifibrotics, blepharitis and prolonged post-operative antibiotics. XEN45 gel stent implant provides a different challenge to ophthalmologists compared to trabeculectomy as more post-operative procedures are required to prevent subconjunctival scarring. Great care should be taken to individualize the use of antifibrotics in each patient to balance the risk of subconjunctival fibrosis with the risk of infection. In patients with stent exposure we propose early closure of the conjunctiva to close off the portal of entry for pathogens and reduce the need for prophylactic topical antibiotics.

8.
Nat Sci Sleep ; 13: 75-91, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33531850

RESUMO

Excessive sleepiness (ES) is a symptom of obstructive sleep apnea (OSA) and narcolepsy that has severe consequences. Wake-promoting drugs and stimulants are utilized as accessory treatment in OSA to reduce propensity to sleep but they do not improve sleep-disordered breathing. Solriamfetol is a first-line therapeutic agent to combat sleepiness in OSA and narcolepsy patients that is approved both by the Food and Drug Administration (FDA) and the European Medicines Agency (EMA). For excessively sleepy adult patients with OSA despite primary treatment or narcolepsy patients without cataplexy, solriamfetol may be used as initial therapy or as replacement therapy in patients who fail treatment or experience unacceptable side effects with modafinil, armodafinil, pitolisant, or stimulants. It can also be used as add-on therapy in OSA or narcolepsy patients when ES is only partially controlled with modafinil, armodafinil, pitolisant, sodium oxybate, or stimulants. Solriamfetol is a phenylalanine derivative whose wake-promoting action may be mediated through its selective dopamine and norepinephrine reuptake inhibition. This paper reviews the profile of solriamfetol in treating ES associated with OSA or narcolepsy and discusses patient selection and clinical perspectives. Mechanism of action, pharmacology, pharmacokinetics, clinical efficacy, and tolerability of solriamfetol are described. The Treatment of OSA and Narcolepsy Excessive Sleepiness (TONES) solriamfetol trials demonstrated the efficacy of solriamfetol in reducing propensity to sleep and maintaining wakefulness, with significant improvements in mean maintenance of wakefulness test (MWT) sleep latencies and significant reduction in Epworth Sleepiness Scale (ESS) scores compared to placebo. With solriamfetol, significantly higher percentages of patients showed improvement in patient's and clinician's global impression of change.

9.
Pediatr Pulmonol ; 56(1): 153-161, 2021 01.
Artigo em Inglês | MEDLINE | ID: mdl-33174693

RESUMO

BACKGROUND AND OBJECTIVE: Bronchiolitis obliterans (BO) is a rare but serious condition. The natural history and outcomes remain poorly understood. In this clinical review, we aimed to describe the clinical characteristics and outcomes of children diagnosed with BO in Hong Kong (HK). METHODS: This was a retrospective study of pediatric patients with BO under the care of six respiratory units in HK from January 1996 to December 2015. Information was retrieved from medical records. RESULTS: Fifty-six patients were included with a male predominance (67.9%). The median age at diagnosis was 1.98 years (interquartile range [IQR]: 0.84-4.99 years). Postinfectious BO (PIBO) was the commonest cause (64.3%) followed by posthematopoietic stem-cell transplant (21.4%). Adenovirus (63.2%) was the commonest causative pathogen among PIBO. The median follow-up duration was 9.7 years (IQR: 2.9-14.3 years). Twenty-five patients (44.6%) could achieve symptom-free recovery at the time of follow-up. Five (8.9%) and three (5.4%) were oxygen or ventilator dependent, respectively. There were two deaths, both had posttransplant BO. Patients who developed BO after transplant had significantly worse lung function than those with PIBO. There were no risk factors significantly associated with worse clinical outcomes (oxygen/ventilator dependence or death) by logistic regression. Among patients with PIBO, coinfection at presentation was significantly associated with persistent symptoms at follow-up (p = .028). CONCLUSIONS: The most common cause of childhood BO in HK is postinfectious and coinfection at presentation was associated with persistent symptoms at follow-up. Further studies are needed to better elucidate disease progression, treatment options and long term outcomes.


Assuntos
Bronquiolite Obliterante/epidemiologia , Infecções por Adenoviridae , Adolescente , Bronquiolite Obliterante/fisiopatologia , Criança , Pré-Escolar , Progressão da Doença , Feminino , Hong Kong/epidemiologia , Humanos , Lactente , Masculino , Estudos Retrospectivos , Fatores de Risco
11.
Expert Opin Pharmacother ; 20(10): 1189-1199, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31136215

RESUMO

Introduction: Narcolepsy is a lifelong central nervous system (CNS) disorder characterized by excessive daytime sleepiness, cataplexy, disturbed nocturnal sleep, hypnagogic hallucinations, and sleep paralysis. Treatment is symptomatic and challenging. Current therapies with wake promoting agents, stimulants, and antidepressants improve symptoms but residual sleepiness or cataplexy may persist. Drug tolerance may develop. Adverse drug effects limit therapy. In the United States, sodium oxybate has been approved to treat daytime sleepiness and cataplexy in adults with narcolepsy since 2002. In 2018, it was approved for children ages 7-17 years with cataplexy with narcolepsy. Areas covered: This drug review includes an overview of narcolepsy, current pharmacotherapy, drug chemistry, pharmacodynamics, pharmacokinetics, and metabolism of sodium oxybate. Published results from 11 randomized control trials are reviewed. Databases searched included PubMed, Google Scholar, Lexi-Comp, Scopus, Science, and Ovid. Expert opinion: Sodium oxybate is an effective therapy for excessive daytime sleepiness and cataplexy in adults and children ages 7-17 years. It is also an effective therapy for disrupted nocturnal sleep. Sodium oxybate improves narcolepsy symptoms and enhances quality of life in narcolepsy patients.


Assuntos
Narcolepsia/tratamento farmacológico , Qualidade de Vida , Oxibato de Sódio/uso terapêutico , Adolescente , Adulto , Antidepressivos/uso terapêutico , Cataplexia/tratamento farmacológico , Estimulantes do Sistema Nervoso Central/administração & dosagem , Criança , Humanos , Ensaios Clínicos Controlados Aleatórios como Assunto , Sono/efeitos dos fármacos , Promotores da Vigília/uso terapêutico
12.
J Vet Diagn Invest ; 31(4): 562-567, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31023162

RESUMO

Three fishers (Martes pennanti), 2 gray foxes (Urocyon cinereoargenteus), 1 mink (Neovison vison), 1 skunk (Mephitis mephitis), and 1 raccoon (Procyon lotor), from Vermont and New Hampshire, had lesions on autopsy consistent with canine distemper virus (CDV) infections diagnosed in a 12-mo period in 2016-2017. Lesions of CDV infection were most commonly noted in the lungs (8 of 8 animals), urothelium (5 of 8), biliary tract (5 of 8), gastrointestinal tract (4 of 7), and brain (4 of 6). Splenic lesions were seen in 3 animals. The diagnosis was confirmed via immunohistochemistry and virus isolation. Viral genotyping indicated that all 8 animals were infected with a distinct clade of CDV that has only been reported in wildlife in New England, and this clade of viruses is distinct from vaccine strains. During the 12 mo when these cases occurred, no other CDV clade was identified in any other wildlife or domesticated animal submitted from the 2 states.


Assuntos
Carnívoros/virologia , Animais , Animais Selvagens , Cinomose/virologia , Vírus da Cinomose Canina/isolamento & purificação
13.
Behav Processes ; 160: 1-9, 2019 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-30650340

RESUMO

Given that many behavior patterns cluster together in sequences that are organized to solve specific problems (e.g., foraging), a fruitful perspective within which to study behaviors is as distinct 'behavior systems'. Unlike many behavior systems that are widespread (e.g., anti-predator behavior, foraging, reproduction), behavior that can be relegated as playful is diverse, involving behavior patterns that are typically present in other behavior systems, sporadic in its phylogenetic distribution and relatively rare, suggesting that play is not a distinct behavior system. Yet the most striking and complex forms of play have the organizational integrity that suggests that it is a behavior system. One model that we develop in this paper, involves three stages of evolutionary transition to account for how the former can evolve into the latter. First, play-like behavior emerges from the incomplete development of other, functional behavior systems in some lineages. Second, in some of those lineages, the behavior patterns typical of particular behavior systems (e.g., foraging) are reorganized, leading to the evolution of specific 'play behavior systems'. Third, some lineages that have independently evolved more than one such play behavior system, coalesce these into a 'super system', allowing some animals to combine behavior patterns from different behavior systems during play. Alternative models are considered, but irrespective of the model, the overall message from this paper is that the conceptual framework of the behavior system approach can provide some new insights into the organization and diversity of play present in the animal kingdom.


Assuntos
Evolução Biológica , Modelos Psicológicos , Jogos e Brinquedos/psicologia , Animais , Comportamento Animal
14.
J Glaucoma ; 28(1): 80-87, 2019 01.
Artigo em Inglês | MEDLINE | ID: mdl-30461553

RESUMO

AIM: To study the microvascular density of the macular and optic nerve head in healthy and glaucoma subjects using optical coherence tomography angiography. METHODOLOGY: We performed a cross-sectional cohort study on healthy subjects and patients with glaucoma. The AngioVue Enhanced Microvascular Imaging System was used to capture the optic nerve head and macula images during one visit. En face segment images of the macular and optic disc were studied in layers. Microvascular density of the optic nerve head and macula were quantified by the number of pixels measured by a novel in-house developed software. Areas under the receiver operating characteristic curves (AUROC) were used to determine the accuracy of differentiating between glaucoma and healthy subjects. RESULTS: A total of 24 (32 eyes) glaucoma subjects (57.5±9.5-y old) and 29 (58 eyes) age-matched controls (51.17±13.5-y old) were recruited. Optic disc and macula scans were performed showing a greater mean vessel density (VD) in healthy compared with glaucoma subjects. The control group had higher VD than the glaucoma group at the en face segmented layers of the optic disc (optic nerve head: 0.209±0.05 vs. 0.110±0.048, P<0.001; vitreoretinal interface: 0.086±0.045 vs. 0.052±0.034, P=0.001; radial peripapillary capillary: 0.146±0.040 vs. 0.053±0.036, P<0.001; and choroid: 0.228±0.074 vs. 0.165±0.062, P<0.001). Similarly, the VD at the macula was also greater in controls than glaucoma patients (superficial retina capillary plexus: 0.115±0.016 vs. 0.088±0.027, P<0.001; deep retina capillary plexus: 0.233±0.027 vs. 0.136±0.073, P<0.001; outer retinal capillary plexus: 0.190±0.057 vs. 0.136±0.105, P=0.036; and choriocapillaris: 0.225±0.053 vs. 0.153±0.068, P<0.001. The AUROC was highest for optic disc radial peripapillary capillary (0.96), followed by nerve head (0.92) and optic disc choroid (0.76). At the macula, the AUROC was highest for deep retina (0.86), followed by choroid (0.84), superficial retina (0.81), and outer retina (0.72). CONCLUSIONS: Microvascular density of the optic disc and macula in glaucoma patients was reduced compared with healthy controls. VD of both optic disc and macula had a high diagnostic ability in differentiating healthy and glaucoma eyes.


Assuntos
Glaucoma de Ângulo Fechado/fisiopatologia , Glaucoma de Ângulo Aberto/fisiopatologia , Macula Lutea/irrigação sanguínea , Disco Óptico/irrigação sanguínea , Vasos Retinianos/patologia , Estudos Transversais , Feminino , Angiofluoresceinografia/métodos , Glaucoma de Ângulo Fechado/diagnóstico por imagem , Glaucoma de Ângulo Aberto/diagnóstico por imagem , Voluntários Saudáveis , Humanos , Pressão Intraocular/fisiologia , Macula Lutea/diagnóstico por imagem , Masculino , Pessoa de Meia-Idade , Disco Óptico/diagnóstico por imagem , Estudos Prospectivos , Curva ROC , Vasos Retinianos/diagnóstico por imagem , Tomografia de Coerência Óptica/métodos
15.
Expert Rev Respir Med ; 12(12): 1007-1019, 2018 12.
Artigo em Inglês | MEDLINE | ID: mdl-30365900

RESUMO

Introduction: Obstructive sleep apnea (OSA) is highly prevalent and constitutes a major health hazard. Current pharmacotherapy is ineffective in correcting sleep-disordered breathing and is used adjunctively to address residual sleepiness. A new drug, solriamfetol, a selective norepinephrine-dopamine reuptake inhibitor, is the first drug of its class that is being considered by the US Food and Drug Administration (FDA) to treat excessive sleepiness in OSA and narcolepsy patients. Areas covered: This review covers drug chemistry, pharmacodynamics, pharmacokinetics, and metabolism of solriamfetol. Results of three Phase 3 trials, Treatment of OSA and Narcolepsy Excessive Sleepiness (TONES 3, 4, 5), relevant to OSA patients are summarized. Published abstracts/articles and a 2017 Jazz Investor Presentation provided data. Databases searched included PubMed, Google Scholar, Lexi-Comp, Scopus, Science, and Ovid. Expert commentary: Solriamfetol shows promise as adjunctive therapy in OSA. It is well tolerated and effective in reducing sleepiness and is an alternative to modafinil or armodafinil. Unlike stimulants like methylphenidate or dextroamphetamine, it does not have cardiac effects, rebound hypersomnia, or withdrawal effects.


Assuntos
Carbamatos/uso terapêutico , Distúrbios do Sono por Sonolência Excessiva/tratamento farmacológico , Distúrbios do Sono por Sonolência Excessiva/etiologia , Apneia Obstrutiva do Sono/complicações , Humanos , Fenilalanina/análogos & derivados
16.
Drugs Aging ; 35(9): 791-817, 2018 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-30058034

RESUMO

Chronic insomnia affects 57% of the elderly in the United States, with impairment of quality of life, function, and health. Chronic insomnia burdens society with billions of dollars in direct and indirect costs of care. The main modalities in the treatment of insomnia in the elderly are psychological/behavioral therapies, pharmacological treatment, or a combination of both. Various specialty societies view psychological/behavioral therapies as the initial treatment intervention. Pharmacotherapy plays an adjunctive role when insomnia symptoms persist or when patients are unable to pursue cognitive behavioral therapies. Current drugs for insomnia fall into different classes: orexin agonists, histamine receptor antagonists, non-benzodiazepine gamma aminobutyric acid receptor agonists, and benzodiazepines. This review focuses on Food and Drug Administration (FDA)-approved drugs for insomnia, including suvorexant, low-dose doxepin, Z-drugs (eszopiclone, zolpidem, zaleplon), benzodiazepines (triazolam, temazepam), and ramelteon. We review the indications, dosing, efficacy, benefits, and harms of these drugs in the elderly, and discuss data on drugs that are commonly used off-label to treat insomnia, and those that are in clinical development. The choice of a hypnotic agent in the elderly is symptom-based. Ramelteon or short-acting Z-drugs can treat sleep-onset insomnia. Suvorexant or low-dose doxepin can improve sleep maintenance. Eszopiclone or zolpidem extended release can be utilized for both sleep onset and sleep maintenance. Low-dose zolpidem sublingual tablets or zaleplon can alleviate middle-of-the-night awakenings. Benzodiazepines should not be used routinely. Trazodone, a commonly used off-label drug for insomnia, improves sleep quality and sleep continuity but carries significant risks. Tiagabine, sometimes used off-label for insomnia, is not effective and should not be utilized. Non-FDA-approved hypnotic agents that are commonly used include melatonin, diphenhydramine, tryptophan, and valerian, despite limited data on benefits and harms. Melatonin slightly improves sleep onset and sleep duration, but product quality and efficacy may vary. Tryptophan decreases sleep onset in adults, but data in the elderly are not available. Valerian is relatively safe but has equivocal benefits on sleep quality. Phase II studies of dual orexin receptor antagonists (almorexant, lemborexant, and filorexant) have shown some improvement in sleep maintenance and sleep continuity. Piromelatine may improve sleep maintenance. Histamine receptor inverse agonists (APD-125, eplivanserin, and LY2624803) improve slow-wave sleep but, for various reasons, the drug companies withdrew their products.


Assuntos
Distúrbios do Início e da Manutenção do Sono/tratamento farmacológico , Idoso , Humanos , Uso Off-Label , Qualidade de Vida , Segurança
17.
J Biol Chem ; 293(28): 10895-10910, 2018 07 13.
Artigo em Inglês | MEDLINE | ID: mdl-29880646

RESUMO

Key contributions to protein structure and stability are provided by weakly polar interactions, which arise from asymmetric electronic distributions within amino acids and peptide bonds. Of particular interest are aromatic side chains whose directional π-systems commonly stabilize protein interiors and interfaces. Here, we consider aromatic-aromatic interactions within a model protein assembly: the dimer interface of insulin. Semi-classical simulations of aromatic-aromatic interactions at this interface suggested that substitution of residue TyrB26 by Trp would preserve native structure while enhancing dimerization (and hence hexamer stability). The crystal structure of a [TrpB26]insulin analog (determined as a T3Rf3 zinc hexamer at a resolution of 2.25 Å) was observed to be essentially identical to that of WT insulin. Remarkably and yet in general accordance with theoretical expectations, spectroscopic studies demonstrated a 150-fold increase in the in vitro lifetime of the variant hexamer, a critical pharmacokinetic parameter influencing design of long-acting formulations. Functional studies in diabetic rats indeed revealed prolonged action following subcutaneous injection. The potency of the TrpB26-modified analog was equal to or greater than an unmodified control. Thus, exploiting a general quantum-chemical feature of protein structure and stability, our results exemplify a mechanism-based approach to the optimization of a therapeutic protein assembly.


Assuntos
Aminoácidos Aromáticos/química , Aminoácidos Aromáticos/metabolismo , Diabetes Mellitus Experimental/prevenção & controle , Insulina/química , Insulina/metabolismo , Receptor de Insulina/metabolismo , Sequência de Aminoácidos , Animais , Cristalografia por Raios X , Dimerização , Masculino , Modelos Moleculares , Ligação Proteica , Conformação Proteica , Ratos , Ratos Endogâmicos Lew
18.
Front Neurosci ; 12: 207, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29670505

RESUMO

Aims: Complex regional pain syndrome (CRPS) is characterized by chronic debilitating pain disproportional to the inciting event and accompanied by motor, sensory, and autonomic disturbances. The pathophysiology of CRPS remains elusive. An exceptional case of severe CRPS leading to forearm amputation provided the opportunity to examine nerve histopathological features of the peripheral nerves. Methods: A 35-year-old female developed CRPS secondary to low voltage electrical injury. The CRPS was refractory to medical therapy and led to functional loss of the forelimb, repeated cutaneous wound infections leading to hospitalization. Specifically, the patient had exhausted a targeted conservative pain management programme prior to forearm amputation. Radial, median, and ulnar nerve specimens were obtained from the amputated limb and analyzed by light and transmission electron microscopy (TEM). Results: All samples showed features of selective myelinated nerve fiber degeneration (47-58% of fibers) on electron microscopy. Degenerating myelinated fibers were significantly larger than healthy fibers (p < 0.05), and corresponded to the larger Aα fibers (motor/proprioception) whilst smaller Aδ (pain/temperature) fibers were spared. Groups of small unmyelinated C fibers (Remak bundles) also showed evidence of degeneration in all samples. Conclusions: We are the first to show large fiber degeneration in CRPS using TEM. Degeneration of Aα fibers may lead to an imbalance in nerve signaling, inappropriately triggering the smaller healthy Aδ fibers, which transmit pain and temperature. These findings suggest peripheral nerve degeneration may play a key role in CRPS. Improved knowledge of pathogenesis will help develop more targeted treatments.

19.
J Comp Psychol ; 132(1): 6-15, 2018 02.
Artigo em Inglês | MEDLINE | ID: mdl-28857605

RESUMO

Play fighting is a commonly reported form of play that involves competitive interactions that generally do not escalate to serious fighting. Although in many species what are competed over are the body targets that are bitten or struck in serious fighting, for many others, the competition can be over other forms of contact, such as sex, social grooming, and predation. In primates, the most detailed studies have been of species such as Old World monkeys, that engage in play fighting that simulates serious fighting, but reports of a number of others, especially among nocturnal prosimians, have noted that play fighting can also involve simulation of sex and grooming. The present study on captive born gray mouse lemurs (Microcebus murinus) provides a quantitative assessment of the relative engagement by juveniles in play fighting involving agonistic and amicable targets. About 80% of play fighting involves competing to groom or mount one another, with a minority involving competing to bite. That these forms of play fighting may be distinct from one another is suggested by the finding that attack on one target does not lead to counterattack on another. The findings are discussed in terms of the evolution and mechanisms underlying play fighting in primates and more widely among animals. (PsycINFO Database Record


Assuntos
Agressão/fisiologia , Comportamento Animal/fisiologia , Cheirogaleidae/fisiologia , Comportamento Competitivo/fisiologia , Jogos e Brinquedos , Animais , Asseio Animal/fisiologia
20.
BMC Nutr ; 4: 9, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-32153873

RESUMO

BACKGROUND: Nutritional deficiencies among school children may hinge on inadequate nutrient intake. School meals should improve nutrient intakes by providing a third of recommended daily energy and nutrient intakes (RNI). The study aimed at evaluating school meals served in three rural schools to determine if they met one third of the RNI of the children. This will enhance meal planning. METHODS: Food samples (20 g) that constituted the school meals were collected for five consecutive days from three schools where school lunch programme was implemented. These were put in labelled small air tight plastic containers and stored in deep freezers in the Department of Home Science, Nutrition and Dietetics, University of Nigeria, Nsukka. The samples were analysed chemically using standard methods. Portion sizes of foods were obtained and the contributions made by these meals to the children's RNI were calculated. Results were presented in percentages and means ± standard deviations. RESULTS: The results showed that energy value of the meals ranged from 32.27 - 243.4 Kcal/100 g. The school meals contained carbohydrate (0.7 - 48.4 g), protein (0.69 - 12.6 g), vitamin C (0.7 - 8.22 mg), vitamin A (3.0 - 255.5 RE), iron (0.05 - 1.7 mg), calcium (3.0 -120 mg) and zinc (0.14 - 3.0 mg) per 100 g of food consumed. They contributed 16.4 - 25.5% energy, 53.4 - 116.9% protein, 66.0 - 159.5% vitamin A, 37.3 - 45.7% vitamin C, 13.2 - 28.5% calcium, 5.9 - 20.6% iron and 35.1 - 92.9% zinc to the children's daily requirements. CONCLUSION: The school meals provided over one third of the RNI for protein, vitamins A and C, and zinc but did not meet a third of the RNI for energy, calcium and iron.

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