RESUMO
Relapse after CD19-directed chimeric antigen receptor T-cell (CAR-T) therapy for large B-cell lymphoma (LBCL) is commonly ascribed to antigen loss or CAR-T exhaustion. Multiantigen targeting and programmed cell death protein-1 blockade are rational approaches to prevent relapse. Here, we test CD19/22 dual-targeting CAR-T (AUTO3) plus pembrolizumab in relapsed/refractory LBCL (NCT03289455). End points include toxicity (primary) and response rates (secondary). Fifty-two patients received AUTO3 and 48/52 received pembrolizumab. Median age was 59 years (range, 27-83), 46/52 had stage III/ IV disease and median follow-up was 21.6 months. AUTO3 was safe; grade 1-2 and grade 3 cytokine release syndrome affected 18/52 (34.6%) and 1/52 (1.9%) patients, neurotoxicity arose in 4 patients (2/4, grade 3-4), and hemophagocytic lymphohistiocytosis affected 2 patients. Outpatient administration was tested in 20 patients, saving a median of 14 hospital days per patient. Overall response rates were 66% (48.9%, complete response [CR]; 17%, partial response). Median duration of remission (DOR) for CR patients was not reached and for all responding patients was 8.3 months (95% confidence interval [CI]: 3.0-not evaluable). 54.4% (CI: 32.8-71.7) of CR patients and 42.6% of all responding patients were projected to remain progression-free at ≥12 months. AUTO3 ± pembrolizumab for relapsed/refractory LBCL was safe and delivered durable remissions in 54.4% of complete responders, associated with robust CAR-T expansion. Neither dual-targeting CAR-T nor pembrolizumab prevented relapse in a significant proportion of patients, and future developments include next-generation-AUTO3, engineered for superior expansion in vivo, and selection of CAR binders active at low antigen densities.
Assuntos
Linfoma Difuso de Grandes Células B , Receptores de Antígenos Quiméricos , Humanos , Pessoa de Meia-Idade , Recidiva Local de Neoplasia , Linfoma Difuso de Grandes Células B/tratamento farmacológico , Imunoterapia Adotiva , Linfócitos T , Antígenos CD19 , Lectina 2 Semelhante a Ig de Ligação ao Ácido SiálicoRESUMO
Change history: In this Letter, author Ana Puhl was inadvertently omitted; this error has been corrected online.An amendment to this paper has been published and can be accessed via a link at the top of the paper.
RESUMO
Stimulator of interferon genes (STING) is a receptor in the endoplasmic reticulum that propagates innate immune sensing of cytosolic pathogen-derived and self DNA1. The development of compounds that modulate STING has recently been the focus of intense research for the treatment of cancer and infectious diseases and as vaccine adjuvants2. To our knowledge, current efforts are focused on the development of modified cyclic dinucleotides that mimic the endogenous STING ligand cGAMP; these have progressed into clinical trials in patients with solid accessible tumours amenable to intratumoral delivery3. Here we report the discovery of a small molecule STING agonist that is not a cyclic dinucleotide and is systemically efficacious for treating tumours in mice. We developed a linking strategy to synergize the effect of two symmetry-related amidobenzimidazole (ABZI)-based compounds to create linked ABZIs (diABZIs) with enhanced binding to STING and cellular function. Intravenous administration of a diABZI STING agonist to immunocompetent mice with established syngeneic colon tumours elicited strong anti-tumour activity, with complete and lasting regression of tumours. Our findings represent a milestone in the rapidly growing field of immune-modifying cancer therapies.
Assuntos
Benzimidazóis/química , Benzimidazóis/farmacologia , Neoplasias do Colo/tratamento farmacológico , Neoplasias do Colo/imunologia , Desenho de Fármacos , Proteínas de Membrana/agonistas , Animais , Benzimidazóis/administração & dosagem , Benzimidazóis/uso terapêutico , Humanos , Ligantes , Proteínas de Membrana/imunologia , Camundongos , Modelos Moleculares , Nucleotídeos Cíclicos/metabolismoRESUMO
The U.S. FDA has permanently removed the in-person prescribing requirements that previously safeguarded the use of mifepristone/misoprostol medical abortions, allowing prescribing through telemedicine or on-line ordering and distribution through the mail and pharmacies, without standard pre-abortion testing. This will increase the risk of complications due to failure to adequately determine the gestational age or rule out ectopic pregnancy by ultrasound or physical exam, failure to perform labs to document whether RhoGAM is indicated, and failure to obtain appropriate informed consent to prevent unwanted abortions, among other concerns. The FDA justified this action by referencing flawed studies with significantly undercounted complications. The details of these study deficiencies are examined in this paper.
Assuntos
Aborto Induzido , Misoprostol , United States Food and Drug Administration , Estados Unidos , Humanos , Gravidez , Aborto Induzido/legislação & jurisprudência , Feminino , Misoprostol/administração & dosagem , Mifepristona/administração & dosagemRESUMO
Unlimited access to information and data sharing wherever and at any time for anyone and anything is a fundamental component of fifth-generation (5G) wireless communication and beyond. Therefore, it has become inevitable to exploit the super-high frequency (SHF) and millimeter-wave (mmWave) frequency bands for future wireless networks due to their attractive ability to provide extremely high data rates because of the availability of vast amounts of bandwidth. However, due to the characteristics and sensitivity of wireless signals to the propagation effects in these frequency bands, more accurate path loss prediction models are vital for the planning, evaluating, and optimizing future wireless communication networks. This paper presents and evaluates the performance of several well-known machine learning methods, including multiple linear regression (MLR), polynomial regression (PR), support vector regression (SVR), as well as the methods using decision trees (DT), random forests (RF), K-nearest neighbors (KNN), artificial neural networks (ANN), and artificial recurrent neural networks (RNN). RNNs are mainly based on long short-term memory (LSTM). The models are compared based on measurement data to provide the best fitting machine-learning-based path loss prediction models. The main results obtained from this study show that the best root-mean-square error (RMSE) performance is given by the ANN and RNN-LSTM methods, while the worst is for the MLR method. All the RMSE values for the given learning techniques are in the range of 0.0216 to 2.9008 dB. Furthermore, this work shows that the models (except for the MLR model) perform excellently in fitting actual measurement data for wireless communications in enclosed indoor environments since they provide R-squared and correlation values higher than 0.91 and 0.96, respectively. The paper shows that these learning methods could be used as accurate and stable models for predicting path loss in the mmWave frequency regime.
Assuntos
Aprendizado de Máquina , Redes Neurais de Computação , Algoritmos , Previsões , Modelos LinearesRESUMO
A half-century of research on the consequences of monocular deprivation (MD) in animals has revealed a great deal about the pathophysiology of amblyopia. MD initiates synaptic changes in the visual cortex that reduce acuity and binocular vision by causing neurons to lose responsiveness to the deprived eye. However, much less is known about how deprivation-induced synaptic modifications can be reversed to restore normal visual function. One theoretically motivated hypothesis is that a period of inactivity can reduce the threshold for synaptic potentiation such that subsequent visual experience promotes synaptic strengthening and increased responsiveness in the visual cortex. Here we have reduced this idea to practice in two species. In young mice, we show that the otherwise stable loss of cortical responsiveness caused by MD is reversed when binocular visual experience follows temporary anesthetic inactivation of the retinas. In 3-mo-old kittens, we show that a severe impairment of visual acuity is also fully reversed by binocular experience following treatment and, further, that prolonged retinal inactivation alone can erase anatomical consequences of MD. We conclude that temporary retinal inactivation represents a highly efficacious means to promote recovery of function.
Assuntos
Ambliopia/terapia , Potenciais Evocados Visuais , Visão Monocular , Animais , Gatos , Feminino , Masculino , Camundongos , Modelos Animais , Recuperação de Função Fisiológica , Acuidade VisualRESUMO
Recent studies conducted on kittens have revealed that the reduced visual acuity of the deprived eye following a short period of monocular deprivation imposed in early life is reversed quickly following a 10-day period spent in total darkness. This study explored the contribution of the fellow eye to the darkness-induced recovery of the acuity of the deprived eye. Upon emergence of kittens from darkness, the fellow eye was occluded for different lengths of time in order to investigate its effects on either the speed or the extent of the recovery of acuity of the deprived eye. Occlusion of the fellow eye for even a day immediately following the period spent in darkness blocked any recovery of the acuity of the deprived eye. Moreover, occlusion of the fellow eye two days after the period of darkness blocked any further visual recovery beyond that achieved in the short period when both eyes were open. The results imply that the darkness-induced recovery of the acuity of the deprived eye depends upon, and is guided by, neural activity in the mature neural connections previously established by the fellow eye.
Assuntos
Ambliopia/fisiopatologia , Fenômenos Fisiológicos Oculares , Privação Sensorial/fisiologia , Visão Ocular/fisiologia , Animais , Gatos , Escuridão , OlhoRESUMO
The capacity for neural plasticity in the mammalian central visual system adheres to a temporal profile in which plasticity peaks early in postnatal development and then declines to reach enduring negligible levels. Early studies to delineate the critical period in cats employed a fixed duration of monocular deprivation to measure the extent of ocular dominance changes induced at different ages. The largest deprivation effects were observed at about 4 weeks postnatal, with a steady decline in plasticity thereafter so that by about 16 weeks only small changes were measured. The capacity for plasticity is regulated by a changing landscape of molecules in the visual system across the lifespan. Studies in rodents and cats have demonstrated that the critical period can be altered by environmental or pharmacological manipulations that enhance plasticity at ages when it would normally be low. Immersion in complete darkness for long durations (dark rearing) has long been known to alter plasticity capacity by modifying plasticity-related molecules and slowing progress of the critical period. In this study, we investigated the possibility that brief darkness (dark exposure) imposed just prior to the critical period peak can enhance the level of plasticity beyond that observed naturally. We examined the level of plasticity by measuring two sensitive markers of monocular deprivation, namely, soma size of neurons and neurofilament labeling within the dorsal lateral geniculate nucleus. Significantly larger modification of soma size, but not neurofilament labeling, was observed at the critical period peak when dark exposure preceded monocular deprivation. This indicated that the natural plasticity ceiling is modifiable and also that brief darkness does not simply slow progress of the critical period. As an antecedent to traditional amblyopia treatment, darkness may increase treatment efficacy even at ages when plasticity is at its highest.
Assuntos
Dominância Ocular/fisiologia , Corpos Geniculados/fisiologia , Plasticidade Neuronal/fisiologia , Vias Visuais/fisiologia , Animais , Animais Recém-Nascidos , Gatos , Período Crítico Psicológico , Escuridão , Neurônios/fisiologia , Privação Sensorial/fisiologia , Córtex Visual/fisiologiaRESUMO
Exposure of kittens to complete darkness for 10 days has been shown (Duffy & Mitchell, 2013) to reverse the loss of visual acuity that follows a prior period of monocular deprivation (MD). In that study, recovery of acuity in the previously deprived eye was fast despite the fact that darkness was imposed 2 months after the period of MD when kittens were 3 months old. In a later study (Holman, Duffy, & Mitchell, 2018), it was demonstrated that the same period of darkness was ineffective when it was imposed on cats about 1 year old, suggesting that dark exposure may only promote recovery when applied within an early critical period. To determine the profile of this critical period, the identical period of darkness (10 days) was imposed on kittens at various ages that had all received the same 7-day period of MD from postnatal day 30 (P30). Recovery of the acuity of the deprived eye as measured by use of a jumping stand was complete when darkness was imposed prior to P186 days, but thereafter, darkness induced progressively smaller acuity improvements and was ineffective in kittens when it began at or beyond P191 days of age. These data indicate a critical period for darkness-induced recovery with an abrupt end over a 5-day period.
Assuntos
Ambliopia/fisiopatologia , Adaptação à Escuridão/fisiologia , Recuperação de Função Fisiológica , Visão Monocular/fisiologia , Acuidade Visual , Ambliopia/terapia , Animais , Gatos , Modelos Animais de Doenças , Seguimentos , Privação SensorialRESUMO
Genetic mutations known to cause intellectual disabilities (IDs) are concentrated in specific sets of genes including both those encoding synaptic proteins and those expressed during early development. We have characterized the effect of genetic deletion of Dlg3, an ID-related gene encoding the synaptic NMDA-receptor interacting protein synapse-associated protein 102 (SAP102), on development of the mouse somatosensory cortex. SAP102 is the main representative of the PSD-95 family of postsynaptic MAGUK proteins during early development and is proposed to play a role in stabilizing receptors at immature synapses. Genetic deletion of SAP102 caused a reduction in the total number of thalamocortical (TC) axons innervating the somatosensory cortex, but did not affect the segregation of barrels. On a synaptic level SAP102 knockout mice display a transient speeding of NMDA receptor kinetics during the critical period for TC plasticity, despite no reduction in GluN2B-mediated component of synaptic transmission. These data indicated an interesting dissociation between receptor kinetics and NMDA subunit expression. Following the critical period NMDA receptor function was unaffected by loss of SAP102 but there was a reduction in the divergence of TC connectivity. These data suggest that changes in synaptic function early in development caused by mutations in SAP102 result in changes in network connectivity later in life.
Assuntos
Desenvolvimento Embrionário/genética , Guanilato Quinases/genética , Deficiência Intelectual/genética , Proteínas de Membrana/genética , Córtex Somatossensorial/crescimento & desenvolvimento , Animais , Humanos , Deficiência Intelectual/fisiopatologia , Camundongos , Camundongos Knockout , Receptores de N-Metil-D-Aspartato/genética , Deleção de Sequência , Córtex Somatossensorial/patologia , Transmissão Sináptica/genéticaRESUMO
We report the results of a multicenter phase 1 dose-escalation study of the selective Bruton tyrosine kinase (BTK) inhibitor ONO/GS-4059 in 90 patients with relapsed/refractory B-cell malignancies. There were 9 dose-escalation cohorts ranging from 20 mg to 600 mg once daily with twice-daily regimens of 240 mg and 300 mg. Twenty-four of 25 evaluable chronic lymphocytic leukemia (CLL) patients (96%) responded to ONO/GS-4059, with a median treatment duration of 80 weeks; 21 CLL patients remain on treatment. Lymph node responses were rapid and associated with a concurrent lymphocytosis. Eleven of 12 evaluable patients with mantle cell lymphoma (92%) responded (median treatment duration, 40 weeks). Eleven of 31 non-germinal center B-cell diffuse large B-cell lymphoma patients (35%) responded but median treatment duration was 12 weeks due to development of progressive disease. ONO/GS-4059 was very well tolerated with 75% of adverse events (AEs) being Common Toxicity Criteria for Adverse Events version 4.0 grade 1 or grade 2. Grade 3/4 AEs were mainly hematologic and recovered spontaneously during therapy. One CLL patient experienced a grade 3 treatment-related bleeding event (spontaneous muscle hematoma) but no clinically significant diarrhea, cardiac dysrhythmias, or arthralgia were observed. No maximal tolerated dose (MTD) was reached in the CLL cohort. In the non-Hodgkin lymphoma cohort, 4 patients developed a dose-limiting toxicity, yielding an MTD of 480 mg once daily. ONO/GS-4059 has significant activity in relapsed/refractory B-cell malignancies without major drug-related toxicity. The selectivity of ONO/GS-4059 should confer advantages in combination therapies. This trial was registered at www.clinicaltrials.gov as #NCT01659255.
Assuntos
Linfócitos B/efeitos dos fármacos , Imidazóis/uso terapêutico , Leucemia Linfocítica Crônica de Células B/tratamento farmacológico , Linfoma Difuso de Grandes Células B/tratamento farmacológico , Linfoma de Célula do Manto/tratamento farmacológico , Inibidores de Proteínas Quinases/uso terapêutico , Proteínas Tirosina Quinases/antagonistas & inibidores , Pirimidinas/uso terapêutico , Adulto , Tirosina Quinase da Agamaglobulinemia , Idoso , Idoso de 80 Anos ou mais , Linfócitos B/patologia , Estudos de Coortes , Feminino , Humanos , Imidazóis/efeitos adversos , Imidazóis/sangue , Leucemia Linfocítica Crônica de Células B/patologia , Linfoma Difuso de Grandes Células B/patologia , Linfoma de Célula do Manto/patologia , Masculino , Pessoa de Meia-Idade , Recidiva Local de Neoplasia/tratamento farmacológico , Recidiva Local de Neoplasia/patologia , Inibidores de Proteínas Quinases/efeitos adversos , Inibidores de Proteínas Quinases/sangue , Pirimidinas/efeitos adversos , Pirimidinas/sangueRESUMO
It has been shown that the visual acuity loss experienced by the deprived eye of kittens following an early period of monocular deprivation (MD) can be alleviated rapidly following 10 days of complete darkness when imposed even as late as 14 weeks of age. To examine whether 10 days of darkness conferred benefits at any age, we measured the extent of recovery of the visual acuity of the deprived eye following the darkness imposed on adult cats that had received the same early period of MD as used in prior experiments conducted on kittens. Parallel studies conducted on different animals examined the extent to which darkness changed the magnitude of the MD-induced laminar differences of the cell soma size and immunoreactivity for the neurofilament (NF) protein in the dorsal lateral geniculate nucleus (dLGN). The results indicated that 10 days of darkness imposed at one year of age neither alleviated the acuity loss of the deprived eye induced by an earlier period of MD nor did it decrease the concurrent lamina differences of the soma size or NF loss in the dLGN.
Assuntos
Adaptação à Escuridão/fisiologia , Escuridão , Plasticidade Neuronal/fisiologia , Visão Ocular/fisiologia , Animais , Gatos , Corpos Geniculados/fisiologia , Acuidade Visual/fisiologia , Córtex Visual/fisiologiaRESUMO
Decreased erythropoietin (EPO) production, shortened erythrocyte survival, and other factors reducing the response to EPO contribute to anemia in patients who have a variety of underlying pathologies such as chronic kidney disease. Treatment with recombinant human EPO (rHuEPO) at supraphysiologic concentrations has proven to be efficacious. However, it does not ameliorate the condition in all patients, and it presents its own risks, including cardiovascular complications. The transcription factors hypoxia-inducible factor (HIF) 1α and HIF2α control the physiologic response to hypoxia and invoke a program of increased erythropoiesis. Levels of HIFα are modulated by oxygen tension via the action of a family of HIF-prolyl hydroxylases (PHDs), which tag HIFα for proteasomal degradation. Inhibition of these PHDs simulates conditions of mild hypoxia, leading to a potentially more physiologic erythropoietic response and presenting a potential alternative to high doses of rHuEPO. Here we describe the discovery and characterization of GSK1278863 [2-(1,3-dicyclohexyl-6-hydroxy-2,4-dioxo-1,2,3,4-tetrahydropyrimidine-5-carboxamido) acetic acid], a pyrimidinetrione-glycinamide low nanomolar inhibitor of PHDs 1-3 that stabilizes HIFα in cell lines, resulting in the production of increased levels of EPO. In normal mice, a single dose of GSK1278863 induced significant increases in circulating plasma EPO but only minimal increases in plasma vascular endothelial growth factor (VEGF-A) concentrations. GSK1278863 significantly increased reticulocytes and red cell mass parameters in preclinical species after once-daily oral administration and has demonstrated an acceptable nonclinical toxicity profile, supporting continued clinical development. GSK1278863 is currently in phase 3 clinical trials for treatment of anemia in patients with chronic kidney disease.
Assuntos
Barbitúricos/farmacologia , Drogas em Investigação/farmacologia , Inibidores Enzimáticos/farmacologia , Eritropoese/efeitos dos fármacos , Eritropoetina/agonistas , Glicina/análogos & derivados , Hematínicos/farmacologia , Prolina Dioxigenases do Fator Induzível por Hipóxia/antagonistas & inibidores , Animais , Barbitúricos/administração & dosagem , Barbitúricos/efeitos adversos , Barbitúricos/farmacocinética , Fatores de Transcrição Hélice-Alça-Hélice Básicos/agonistas , Fatores de Transcrição Hélice-Alça-Hélice Básicos/química , Fatores de Transcrição Hélice-Alça-Hélice Básicos/metabolismo , Linhagem Celular Tumoral , Cães , Relação Dose-Resposta a Droga , Drogas em Investigação/administração & dosagem , Drogas em Investigação/efeitos adversos , Drogas em Investigação/farmacocinética , Inibidores Enzimáticos/administração & dosagem , Inibidores Enzimáticos/efeitos adversos , Inibidores Enzimáticos/farmacocinética , Eritropoetina/genética , Eritropoetina/metabolismo , Feminino , Glicina/administração & dosagem , Glicina/efeitos adversos , Glicina/farmacocinética , Glicina/farmacologia , Hematínicos/administração & dosagem , Hematínicos/efeitos adversos , Hematínicos/farmacocinética , Humanos , Subunidade alfa do Fator 1 Induzível por Hipóxia/agonistas , Subunidade alfa do Fator 1 Induzível por Hipóxia/química , Subunidade alfa do Fator 1 Induzível por Hipóxia/metabolismo , Prolina Dioxigenases do Fator Induzível por Hipóxia/genética , Prolina Dioxigenases do Fator Induzível por Hipóxia/metabolismo , Isoenzimas/antagonistas & inibidores , Isoenzimas/genética , Isoenzimas/metabolismo , Masculino , Camundongos , Estabilidade Proteica/efeitos dos fármacos , Ratos Sprague-Dawley , Proteínas Recombinantes/química , Proteínas Recombinantes/metabolismo , Testes de Toxicidade CrônicaRESUMO
ONO-2952, a novel antagonist of translocator protein 18 kDa (TSPO), binds with high affinity to TSPO in rat brain and human tumor cell line membrane preparations. This study used the TSPO-specific PET radioligand [11 C]PBR28 to confirm binding of ONO-2952 to brain TSPO in human subjects, and evaluate brain TSPO occupancy and its relationship with ONO-2952 plasma concentration. Sixteen healthy subjects received a single oral dose of 200, 60, 20, or 6 mg ONO-2952 (n = 4 per dose). Two PET scans with [11 C]PBR28 were conducted ≤7 days apart: at baseline and 24 h after ONO-2952 administration. [11 C]PBR28 regional distribution volume (VT ) was derived with kinetic modeling using the arterial input function and a two tissue compartment model. Nonspecific binding (VND ) was obtained on an individual basis for each subject using linear regression as the x-intercept of the Lassen plot. The binding potential relative to VND (BPND ) was derived as the difference between VT in the ROI (VT ROI) and VND , normalized to VND ; BPND = (VT ROI - VND )/VND . TSPO occupancy was calculated as the change in BPND (ΔBPND ) from individual's baseline scan to the on-medication scan to the baseline BPND value. TSPO occupancy by ONO-2952 was dose dependent between 20-200 mg, approaching saturation at 200 mg both in the whole brain and in 15 anatomic regions of interest (ROI). Estimated Ki values ranged from 24.1 to 72.2 nM. This open-label, single-center, single-dose study demonstrated engagement of ONO-2952 to brain TSPO. The relationship between pharmacokinetics and TSPO occupancy observed in this study support the hypothesis that ONO-2952 could potentially modulate neurosteroid production by binding to brain TSPO.
Assuntos
Encéfalo/diagnóstico por imagem , Encéfalo/metabolismo , Ciclopropanos/farmacologia , Antagonistas GABAérgicos/farmacologia , Compostos Heterocíclicos de 4 ou mais Anéis/farmacologia , Receptores de GABA/metabolismo , Acetamidas , Adulto , Radioisótopos de Carbono , Ciclopropanos/efeitos adversos , Ciclopropanos/sangue , Relação Dose-Resposta a Droga , Feminino , Seguimentos , Antagonistas GABAérgicos/efeitos adversos , Antagonistas GABAérgicos/sangue , Compostos Heterocíclicos de 4 ou mais Anéis/efeitos adversos , Compostos Heterocíclicos de 4 ou mais Anéis/sangue , Humanos , Modelos Lineares , Imageamento por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Tomografia por Emissão de Pósitrons , Piridinas , Compostos Radiofarmacêuticos , Adulto JovemRESUMO
KEY POINTS: Occlusion of one eye of kittens (monocular deprivation) results in a severe and permanent loss of visual acuity in that eye, which parallels closely the vision loss characteristic of human amblyopia. We extended earlier work to demonstrate that amblyopic vision loss can be either blocked or erased very fast by a 10 day period of total darkness following a period of monocular deprivation that begins near birth and extends to at least 8 weeks of age. The parameters of darkness were strict because no visual recovery was observed after 5 days of darkness. In addition, short periods of light introduced each day during an otherwise 10 day period of darkness obliterated the benefits. Despite recovery of normal visual acuity, only one-quarter of the animals showed evidence of having attained normal stereoscopic vision. A period of total darkness may catalyse and improve treatment outcomes in amblyopic children. A 10 day period of total darkness has been shown to either block or erase the severe effects on vision of a prior short period of monocular deprivation (MD) in kittens depending on whether darkness is contiguous or is delayed with respect to the period of MD. We have extended these earlier findings from kittens for which the period of MD began at 1 month and lasted for 1 week to more clinically relevant situations where MD began near birth and lasted for ≥ 6 weeks. Despite the far longer MD and the absence of prior binocular vision, all animals recovered normal visual acuity in the previously deprived eye. As before, when the period of darkness followed immediately after MD, the vision of both eyes was initially very poor but, subsequently, the acuity of each eye increased gradually and equally to attain normal levels in â¼ 7 weeks. By contrast, when darkness was introduced 8 weeks after MD, the visual acuity of the deprived eye recovered quickly to normal levels in just 1 week without any change in the vision of the fellow (non-deprived) eye. Short (15 or 30 min) periods of illumination each day during an otherwise 10 day period of darkness obliterated all the benefits for vision, and a 5 day period of darkness was also completely ineffective. Measurements of depth perception indicated that, despite possessing normal visual acuity in both eyes, only about one-quarter of the animals showed evidence of having attained normal stereoscopic vision.
Assuntos
Ambliopia/fisiopatologia , Escuridão , Recuperação de Função Fisiológica , Acuidade Visual , Animais , Gatos , Percepção de Profundidade , Feminino , Masculino , Visão OcularRESUMO
Extended periods of darkness have long been used to study how the mammalian visual system develops in the absence of any instruction from vision. Because of the relative ease of implementation of darkness as a means to eliminate visually driven neural activity, it has usually been imposed earlier in life and for much longer periods than was the case for other manipulations of the early visual input used for study of their influences on visual system development. Recently, it was shown that following a very brief (10 days) period of darkness imposed at five weeks of age, kittens emerged blind. Although vision as assessed by measurements of visual acuity eventually recovered, the time course was very slow as it took seven weeks for visual acuity to attain normal levels. Here, we document the critical period of this remarkable vulnerability to the effects of short periods of darkness by imposing 10 days of darkness on nine normal kittens at progressively later ages. Results indicate that the period of susceptibility to darkness extends only to about 10 weeks of age, which is substantially shorter than the critical period for the effects of monocular deprivation in the primary visual cortex, which extends beyond six months of age.
Assuntos
Cegueira/fisiopatologia , Período Crítico Psicológico , Escuridão , Acuidade Visual , Fatores Etários , Animais , Comportamento Animal , Cegueira/psicologia , Gatos , Privação Sensorial , Fatores de TempoRESUMO
The parallel processing of visual features by distinct neuron populations is a central characteristic of the mammalian visual system. In the A laminae of the cat dorsal lateral geniculate nucleus (dLGN), parallel processing streams originate from two principal neuron types, called X and Y cells. Disruption of visual experience early in life by monocular deprivation has been shown to alter the structure and function of Y cells, but the extent to which deprivation influences X cells remains less clear. A transcription factor, FoxP2, has recently been shown to selectively label X cells in the ferret dLGN and thus provides an opportunity to examine whether monocular deprivation alters the soma size of X cells. In this study, FoxP2 labeling was examined in the dLGN of normal and monocularly deprived cats. The characteristics of neurons labeled for FoxP2 were consistent with FoxP2 being a marker for X cells in the cat dLGN. Monocular deprivation for either a short (7 days) or long (7 weeks) duration did not alter the density of FoxP2-positive neurons between nondeprived and deprived dLGN layers. However, for each deprived animal examined, measurement of the cross-sectional area of FoxP2-positive neurons (X cells) revealed that within deprived layers, X cells were smaller by approximately 20% after 7 days of deprivation, and by approximately 28% after 7 weeks of deprivation. The observed alteration to the cross-sectional area of X cells indicates that perturbation of this major pathway contributes to the functional impairments that develop from monocular deprivation.
Assuntos
Fatores de Transcrição Forkhead/metabolismo , Lateralidade Funcional/fisiologia , Regulação da Expressão Gênica/fisiologia , Corpos Geniculados/patologia , Neurônios/metabolismo , Neurônios/patologia , Privação Sensorial , Animais , Animais Recém-Nascidos , Gatos , Contagem de CélulasRESUMO
Although amblyopia typically manifests itself as a monocular condition, its origin has long been linked to unbalanced neural signals from the two eyes during early postnatal development, a view confirmed by studies conducted on animal models in the last 50 years. Despite recognition of its binocular origin, treatment of amblyopia continues to be dominated by a period of patching of the non-amblyopic eye that necessarily hinders binocular co-operation. This review summarizes evidence from three lines of investigation conducted on an animal model of deprivation amblyopia to support the thesis that treatment of amblyopia should instead focus upon procedures that promote and enhance binocular co-operation. First, experiments with mixed daily visual experience in which episodes of abnormal visual input were pitted against normal binocular exposure revealed that short exposures of the latter offset much longer periods of abnormal input to allow normal development of visual acuity in both eyes. Second, experiments on the use of part-time patching revealed that purposeful introduction of episodes of binocular vision each day could be very beneficial. Periods of binocular exposure that represented 30-50% of the daily visual exposure included with daily occlusion of the non-amblyopic could allow recovery of normal vision in the amblyopic eye. Third, very recent experiments demonstrate that a short 10 day period of total darkness can promote very fast and complete recovery of visual acuity in the amblyopic eye of kittens and may represent an example of a class of artificial environments that have similar beneficial effects. Finally, an approach is described to allow timing of events in kitten and human visual system development to be scaled to optimize the ages for therapeutic interventions.
Assuntos
Ambliopia/terapia , Estimulação Luminosa/métodos , Privação Sensorial , Visão Binocular , Ambliopia/fisiopatologia , Animais , Modelos Animais de Doenças , Humanos , Acuidade VisualRESUMO
Amblyopia is a form of visual cortical impairment that arises from abnormal visual experience early in life. Most often, amblyopia is a unilateral visual impairment that can develop as a result of strabismus, anisometropia, or a combination of these conditions that result in discordant binocular experience. Characterized by reduced visual acuity and impaired binocular function, amblyopia places a substantial burden on the developing child. Although frontline treatment with glasses and patching can improve visual acuity, residual amblyopia remains for most children. Newer binocular-based therapies can elicit rapid recovery of visual acuity and may also improve stereoacuity in some children. Nevertheless, for both treatment modalities full recovery is elusive, recurrence of amblyopia is common, and improvements are negligible when treatment is administered at older ages. Insights derived from animal models about the factors that govern neural plasticity have been leveraged to develop innovative treatments for amblyopia. These novel therapies exhibit efficacy to promote recovery, and some are effective even at ages when conventional treatments fail to yield benefit. Approaches for enhancing visual system plasticity and promoting recovery from amblyopia include altering the balance between excitatory and inhibitory mechanisms, reversing the accumulation of proteins that inhibit plasticity, and harnessing the principles of metaplasticity. Although these therapies have exhibited promising results in animal models, their safety and ability to remediate amblyopia need to be evaluated in humans.
RESUMO
The programme aimed to improve selected cardiometabolic risk (CMR) variables using a nutritional intervention among farmers who reported hypertensive disorders as hindrances during agricultural activities. The intervention had two case controls (n = 103) [experimental group-EG (n = 53) and control group-CG (n = 50)] which were tracked and whose blood pressure measurements, dietary intake, blood indices for cholesterol concentration and glucose levels from pre- and post-intervention surveys after the baseline survey (n = 112) were analysed. The interval for data collection was 12 weeks (±120 days) after five legume varieties were consumed between 3 and 5 times a day, and servings were not <125 g per at least three times per week. Sixty-five per cent of farmers were above 60 years old, with mean age ranges of 63.3 (SD ± 6.3) years for women and 67.2 (SD ± 6.7) for men. The post-intervention survey revealed that EG blood results indicated nutrient improvement with p <= 0.05 for blood glucose (p = 0.003) and cholesterol (p = 0.001) as opposed to the CG. A trend analysis revealed that cholesterol (p = 0.033) and systolic blood pressure (SBP); (p = 0.013) were statistically significant when comparing genders for all study phases. Interventions focusing on legumes can improve hypertension and cardiovascular disease and fast-track the achievement of SGDs 3 and 12 through community-based programmes.