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1.
Nature ; 628(8008): 511-514, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38632480

RESUMO

Beyond our Solar System, aurorae have been inferred from radio observations of isolated brown dwarfs1,2. Within our Solar System, giant planets have auroral emission with signatures across the electromagnetic spectrum including infrared emission of H3+ and methane. Isolated brown dwarfs with auroral signatures in the radio have been searched for corresponding infrared features, but only null detections have been reported3. CWISEP J193518.59-154620.3. (W1935 for short) is an isolated brown dwarf with a temperature of approximately 482 K. Here we report James Webb Space Telescope observations of strong methane emission from W1935 at 3.326 µm. Atmospheric modelling leads us to conclude that a temperature inversion of approximately 300 K centred at 1-10 mbar replicates the feature. This represents an atmospheric temperature inversion for a Jupiter-like atmosphere without irradiation from a host star. A plausible explanation for the strong inversion is heating by auroral processes, although other internal and external dynamical processes cannot be ruled out. The best-fitting model rules out the contribution of H3+ emission, which is prominent in Solar System gas giants. However, this is consistent with rapid destruction of H3+ at the higher pressure where the W1935 emission originates4.

2.
J Urol ; 209(6): 1112-1119, 2023 06.
Artigo em Inglês | MEDLINE | ID: mdl-36951811

RESUMO

PURPOSE: Despite family history being an established risk factor for prostate cancer, the role of a broader definition of family history inclusive of not just prostate cancer but other genetically related malignancies has not been investigated in the active surveillance population. Here, we evaluate the impact of an expanded definition of family history on active surveillance outcomes. MATERIALS AND METHODS: Patients undergoing active surveillance for prostate cancer at Massachusetts General Hospital from 1997-2019 with detailed data available on family cancer history were identified. Primary outcome was biopsy progression-free survival, and secondary outcomes were treatment-free survival, adverse pathological features at prostatectomy, and biochemical recurrence after treatment. Statistical analyses were conducted using the Kaplan-Meier method and Cox regression. RESULTS: Among 855 evaluable patients, 300 (35.1%) patients had any family history of prostate cancer, and 95 (11.1%) had a family history of related malignancies suggestive of a hereditary cancer syndrome. Family history of prostate cancer alone was not associated with biopsy progression, whereas family history suggestive of a hereditary cancer syndrome was associated with a significantly increased risk of biopsy progression (HR 1.43, 95%CI 1.01-2.02), independent of other known clinicopathological risk factors in multivariable analysis. Similarly, family history suggestive of a hereditary cancer syndrome was associated with significantly lower treatment-free survival (HR 1.58, 95%CI 1.14-2.18) in multivariable analysis. No significant association was found between family history and adverse features on surgical pathology or biochemical recurrence. CONCLUSIONS: An expanded family history suggestive of a hereditary cancer syndrome is an independent predictor of biopsy progression during active surveillance. Men with such a family history may still be offered active surveillance but should be counseled regarding the higher risk of disease progression.


Assuntos
Neoplasias da Próstata , Conduta Expectante , Masculino , Humanos , Conduta Expectante/métodos , Estudos Retrospectivos , Neoplasias da Próstata/patologia , Prostatectomia , Fatores de Risco , Gradação de Tumores , Antígeno Prostático Específico
3.
Liver Transpl ; 28(11): 1709-1715, 2022 11.
Artigo em Inglês | MEDLINE | ID: mdl-35596660

RESUMO

We perform routine preprocurement image-guided percutaneous liver biopsies on potential donation after circulatory death (DCD) liver donors. The purpose of this study was to examine the impact of preprocurement liver biopsy on the use of livers from DCD donors. We retrospectively reviewed demographics, liver histology, and disposition of DCD liver donors within a single organ procurement organization (OPO) who underwent preprocurement liver biopsy from January 2000 through December 2019. A total of 212 potential donors underwent prerecovery biopsy. No donors were lost as a result of complications of biopsy. Of these, 183 (86.3%) had acceptable biopsies: 146 (79.8%) were successfully transplanted and 37 (20.2%) were deemed not suitable for transplant. In contrast, of 120 DCD livers recovered with the intent to transplant that were not biopsied prior to recovery, 59 (49.2%) were successfully transplanted, and 61 (50.8%) were deemed not suitable for transplant. A total of 14 donors were ruled out for transplant based on prerecovery histology. Successfully transplanted livers that underwent preprocurement biopsy were more likely to come from donors aged older than 50 years or with body mass index more than 30 kg/m2 compared with successfully transplanted livers without a prerecovery biopsy. Biopsy excluded 6.6% of DCD donor livers for transplant prior to recovery and facilitated the successful recovery and transplant of two-thirds of potential DCD donor livers. Livers intended for transplant at the time of recovery that did not undergo preprocurement biopsy were more likely to not be recovered or to be discarded. Preprocurement biopsy provides additional histologic information prior to deploying resources and helps to identify usable livers that might otherwise be declined for transplant. Consideration of liver biopsy in this group benefits OPOs and transplant centers by maximizing organ use and optimizing resource deployment.


Assuntos
Transplante de Fígado , Obtenção de Tecidos e Órgãos , Idoso , Biópsia , Morte , Sobrevivência de Enxerto , Humanos , Transplante de Fígado/efeitos adversos , Estudos Retrospectivos , Doadores de Tecidos
4.
J Exp Bot ; 71(6): 2198-2209, 2020 03 25.
Artigo em Inglês | MEDLINE | ID: mdl-31912143

RESUMO

How plant-associated microbiota are shaped by, and potentially contribute to, the unique ecology and heterotrophic life history of parasitic plants is relatively unknown. Here, we investigate the leaf and root bacterial communities of the root holoparasite Orobanche hederae and its host Hedera spp. from natural populations. Root bacteria inhabiting Orobanche were less diverse, had fewer co-associations, and displayed increased compositional similarity to leaf bacteria relative to Hedera. Overall, Orobanche bacteria exhibited significant congruency with Hedera root bacteria across sites, but not the surrounding soil. Infection had localized and systemic effects on Hedera bacteria, which included effects on the abundance of individual taxa and root network properties. Collectively, our results indicate that the parasitic plant microbiome is derived but distinct from the host plant microbiota, exhibits increased homogenization between shoot and root tissues, and displays far fewer co-associations among individual bacterial members. Host plant infection is accompanied by modest changes of associated microbiota at both local and systemic scales compared with uninfected individuals. Our results are a first step towards extending the growing insight into the assembly and function of the plant microbiome to include the ecologically unique but often overlooked guild of heterotrophic plants.


Assuntos
Microbiota , Orobanche , Bactérias , Ecologia , Folhas de Planta , Raízes de Plantas , Microbiologia do Solo
5.
Proc Biol Sci ; 285(1887)2018 09 19.
Artigo em Inglês | MEDLINE | ID: mdl-30232155

RESUMO

Foundational studies of chloroplast genome (plastome) evolution in parasitic plants have focused on broad trends across large clades, particularly among the Orobanchaceae, a species-rich and ecologically diverse family of root parasites. However, the extent to which such patterns and processes of plastome evolution, such as stepwise gene loss following the complete loss of photosynthesis (shift to holoparasitism), are detectable at shallow evolutionary time scale is largely unknown. We used genome skimming to assemble eight chloroplast genomes representing complete taxonomic sampling of Aphyllon sect. Aphyllon, a small clade within the Orobanchaceae that evolved approximately 6 Ma, long after the origin of holoparasitism. We show substantial plastome reduction occurred in the stem lineage, but subsequent change in plastome size, gene content, and structure has been relatively minimal, albeit detectable. This lends additional fine-grained support to existing models of stepwise plastome reduction in holoparasitic plants. Additionally, we report phylogenetic evidence based on an rbcL gene tree and assembled 60+ kb fragments of the Aphyllon epigalium mitochondrial genome indicating host-to-parasite horizontal gene transfers (hpHGT) of several genes originating from the plastome of an ancient Galium host into the mitochondrial genome of a recent common ancestor of A. epigalium Ecologically, this evidence of hpHGT suggests that the host-parasite associations between Galium and A. epigalium have been stable at least since its subspecies diverged hundreds of thousands of years ago.


Assuntos
Galium/parasitologia , Transferência Genética Horizontal , Genoma de Cloroplastos/genética , Orobanchaceae/genética , Evolução Biológica , Galium/genética , Genes de Plantas , Genoma Mitocondrial , Filogenia , Seleção Genética
7.
Am J Bot ; 104(11): 1745-1755, 2017 11.
Artigo em Inglês | MEDLINE | ID: mdl-29170246

RESUMO

PREMISE OF THE STUDY: Aphyllon is a clade of holoparasites that includes closely related North American and South American species parasitic on Grindelia. Both Aphyllon (Orobanchaceae) and Grindelia (Asteraceae) have amphitropical disjunctions between North America and South America; however, the timing of these patterns and the processes to explain them are unknown. METHODS: Chronograms for the Orobanchaceae and Grindelia and their relatives were constructed using fossil and secondary calibration points, one of which was based on the inferred timing of horizontal gene transfer from a papilionoid legume into the common ancestor of Orobanche and Phelipanche. Elevated rates of molecular evolution in the Orobanchaceae have hindered efforts to determine reliable divergence time estimates in the absence of a fossil record. However, using a horizontal gene transfer event as a secondary calibration overcomes this limitation. These chronograms were used to reconstruct the biogeography of Aphyllon, Grindelia, and relatives using a DEC+J model implemented in RevBayes. KEY RESULTS: Aphyllon had two amphitropical dispersals from North America to South America, while Grindelia had a single dispersal. The dispersal of the Aphyllon lineage that is parasitic on Grindelia (0.40 Ma) took place somewhat after Grindelia began to diversify in South America (0.93 Ma). Using a secondary calibration based on horizontal gene transfer, we infer more recent divergence dates of holoparasitic Orobancheae than previous studies. CONCLUSIONS: Parallel host-parasite amphitropical disjunctions in Grindelia and Aphyllon illustrate one means by which ecological specialization may result in nonindependent patterns of diversity in distantly related lineages. Although Grindelia and Aphyllon both dispersed to South America recently, Grindelia appears to have diversified more extensively following colonization. More broadly, recent Pleistocene glaciations probably have also contributed to patterns of diversity and biogeography of temperate northern hemisphere Orobancheae. We also demonstrate the utility of using horizontal gene transfer events from well-dated clades to calibrate parasite phylogenies in the absence of a fossil record.


Assuntos
Grindelia/parasitologia , Orobanchaceae/fisiologia , Doenças das Plantas/parasitologia , Dispersão Vegetal , Ecologia , Evolução Molecular , Fósseis , América do Norte , Orobanchaceae/genética , Filogenia , América do Sul
8.
J Neurosci ; 35(14): 5522-36, 2015 Apr 08.
Artigo em Inglês | MEDLINE | ID: mdl-25855169

RESUMO

Efficient processing of incoming sensory input is essential for an organism's survival. A growing body of evidence suggests that sensory systems have developed coding strategies that are constrained by the statistics of the natural environment. Consequently, it is necessary to first characterize neural responses to natural stimuli to uncover the coding strategies used by a given sensory system. Here we report for the first time the statistics of vestibular rotational and translational stimuli experienced by rhesus monkeys during natural (e.g., walking, grooming) behaviors. We find that these stimuli can reach intensities as high as 1500 deg/s and 8 G. Recordings from afferents during naturalistic rotational and linear motion further revealed strongly nonlinear responses in the form of rectification and saturation, which could not be accurately predicted by traditional linear models of vestibular processing. Accordingly, we used linear-nonlinear cascade models and found that these could accurately predict responses to naturalistic stimuli. Finally, we tested whether the statistics of natural vestibular signals constrain the neural coding strategies used by peripheral afferents. We found that both irregular otolith and semicircular canal afferents, because of their higher sensitivities, were more optimized for processing natural vestibular stimuli as compared with their regular counterparts. Our results therefore provide the first evidence supporting the hypothesis that the neural coding strategies used by the vestibular system are matched to the statistics of natural stimuli.


Assuntos
Vias Auditivas/fisiologia , Movimentos da Cabeça/fisiologia , Membrana dos Otólitos/fisiologia , Vestíbulo do Labirinto/fisiologia , Potenciais de Ação/fisiologia , Animais , Gravitação , Modelos Lineares , Macaca fascicularis , Masculino , Distribuição Normal , Rotação
9.
Ann Bot ; 118(6): 1101-1111, 2016 11.
Artigo em Inglês | MEDLINE | ID: mdl-27539600

RESUMO

BACKGROUND AND AIMS: The broomrapes, Orobanche sensu lato (Orobanchaceae), are common root parasites found across Eurasia, Africa and the Americas. All species native to the western hemisphere, recognized as Orobanche sections Gymnocaulis and Nothaphyllon, form a clade that has a centre of diversity in western North America, but also includes four disjunct species in central and southern South America. The wide ecological distribution coupled with moderate taxonomic diversity make this clade a valuable model system for studying the role, if any, of host-switching in driving the diversification of plant parasites. METHODS: Two spacer regions of ribosomal nuclear DNA (ITS + ETS), three plastid regions and one low-copy nuclear gene were sampled from 163 exemplars of Orobanche from across the native geographic range in order to infer a detailed phylogeny. Together with comprehensive data on the parasites' native host ranges, associations between phylogenetic lineages and host specificity are tested. KEY RESULTS: Within the two currently recognized species of O. sect. Gymnocaulis, seven strongly supported clades were found. While commonly sympatric, members of these clades each had unique host associations. Strong support for cryptic host-specific diversity was also found in sect. Nothaphyllon, while other taxonomic species were well supported. We also find strong evidence for multiple amphitropical dispersals from central North America into South America. CONCLUSIONS: Host-switching is an important driver of diversification in western hemisphere broomrapes, where host specificity has been grossly underestimated. More broadly, host specificity and host-switching probably play fundamental roles in the speciation of parasitic plants.


Assuntos
Orobanche/fisiologia , Biodiversidade , América Central , DNA de Plantas/genética , DNA Espaçador Ribossômico/genética , Ecologia , América do Norte , Orobanche/genética , Filogenia , Plastídeos/genética , Alinhamento de Sequência , Análise de Sequência de DNA , América do Sul
10.
Am J Bot ; 103(2): 221-32, 2016 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-26851267

RESUMO

PREMISE OF THE STUDY: Hesperolinon (western flax; Linaceae) is endemic to the western United States, where it is notable for its high and geographically concentrated species diversity on serpentine-derived soils and for its use as a model system in disease ecology. We used a phylogenetic framework to test a long-standing hypothesis that Hesperolinon is a neoendemic radiation. METHODS: Five plastid and two ribosomal nuclear DNA gene regions were sampled from 105 populations of Hesperolinon, including all 13 recently recognized species across their known ranges. We used these data to generate population-level phylogenies of Hesperolinon. We also generated a robustly sampled chronogram of Linaceae using an eight-gene, 100-taxon supermatrix calibrated using fossil Linum pollen and a published chronogram of Malpighiales. KEY RESULTS: Most diversification in Hesperolinon has taken place in the past 1-2 million yr, much more recently than previous estimates. Only the earliest-diverging species, H. drymarioides, was resolved as a clade. Denser taxon and gene sampling generally support previously proposed relationships within Linaceae, but with more recent diversification of key clades. CONCLUSIONS: Hesperolinon is an excellent example of edaphic neoendemism, in support of Raven and Axelrod's hypothesis for the genus. Dense population-level sampling reveals a complex of incipient species, with clades poorly aligned with traditional morphological circumscriptions, likely due in part to continued gene flow. The diversification of Linaceae is more recent than previously estimated, and other recent radiations (e.g., Hugonia) warrant further study.


Assuntos
Evolução Molecular , Linaceae/genética , Filogenia , Evolução Biológica , California , DNA de Cloroplastos/genética , DNA Ribossômico/genética , Linaceae/fisiologia , Dados de Sequência Molecular , Oregon , Análise de Sequência de DNA
11.
PLoS Biol ; 10(7): e1001365, 2012.
Artigo em Inglês | MEDLINE | ID: mdl-22911113

RESUMO

Although it is well established that the neural code representing the world changes at each stage of a sensory pathway, the transformations that mediate these changes are not well understood. Here we show that self-motion (i.e. vestibular) sensory information encoded by VIIIth nerve afferents is integrated nonlinearly by post-synaptic central vestibular neurons. This response nonlinearity was characterized by a strong (~50%) attenuation in neuronal sensitivity to low frequency stimuli when presented concurrently with high frequency stimuli. Using computational methods, we further demonstrate that a static boosting nonlinearity in the input-output relationship of central vestibular neurons accounts for this unexpected result. Specifically, when low and high frequency stimuli are presented concurrently, this boosting nonlinearity causes an intensity-dependent bias in the output firing rate, thereby attenuating neuronal sensitivities. We suggest that nonlinear integration of afferent input extends the coding range of central vestibular neurons and enables them to better extract the high frequency features of self-motion when embedded with low frequency motion during natural movements. These findings challenge the traditional notion that the vestibular system uses a linear rate code to transmit information and have important consequences for understanding how the representation of sensory information changes across sensory pathways.


Assuntos
Percepção de Movimento/fisiologia , Movimento/fisiologia , Neurônios Aferentes/fisiologia , Vestíbulo do Labirinto/fisiologia , Estimulação Acústica/métodos , Animais , Encéfalo/fisiologia , Biologia Computacional , Macaca , Vias Neurais/fisiologia , Dinâmica não Linear , Postura/fisiologia , Núcleos Vestibulares/fisiologia
12.
Glob Chang Biol ; 20(9): 2841-55, 2014 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-24934878

RESUMO

Understanding recent biogeographic responses to climate change is fundamental for improving our predictions of likely future responses and guiding conservation planning at both local and global scales. Studies of observed biogeographic responses to 20th century climate change have principally examined effects related to ubiquitous increases in temperature - collectively termed a warming fingerprint. Although the importance of changes in other aspects of climate - particularly precipitation and water availability - is widely acknowledged from a theoretical standpoint and supported by paleontological evidence, we lack a practical understanding of how these changes interact with temperature to drive biogeographic responses. Further complicating matters, differences in life history and ecological attributes may lead species to respond differently to the same changes in climate. Here, we examine whether recent biogeographic patterns across California are consistent with a warming fingerprint. We describe how various components of climate have changed regionally in California during the 20th century and review empirical evidence of biogeographic responses to these changes, particularly elevational range shifts. Many responses to climate change do not appear to be consistent with a warming fingerprint, with downslope shifts in elevation being as common as upslope shifts across a number of taxa and many demographic and community responses being inconsistent with upslope shifts. We identify a number of potential direct and indirect mechanisms for these responses, including the influence of aspects of climate change other than temperature (e.g., the shifting seasonal balance of energy and water availability), differences in each taxon's sensitivity to climate change, trophic interactions, and land-use change. Finally, we highlight the need to move beyond a warming fingerprint in studies of biogeographic responses by considering a more multifaceted view of climate, emphasizing local-scale effects, and including a priori knowledge of relevant natural history for the taxa and regions under study.


Assuntos
Altitude , Distribuição Animal , Aves/fisiologia , Borboletas/fisiologia , Mudança Climática/estatística & dados numéricos , Mamíferos/fisiologia , Fenômenos Fisiológicos Vegetais , Aclimatação/fisiologia , Animais , California , Conservação dos Recursos Naturais/métodos , Demografia , Previsões/métodos , Dinâmica Populacional , Especificidade da Espécie
13.
Clin Nutr ESPEN ; 63: 557-563, 2024 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-39047868

RESUMO

BACKGROUND AND AIMS: In the recent years creatine has been shown promising results in patients with neurodegenerative diseases, myopathies and dystrophies. Cardiovascular diseases could be another pathology that can benefit from creatine supplementation, considering the influence on the risk factors associated with the development of cardiovascular diseases including reduction in chronic inflammation, and improved control of hyperglycemia and dyslipidemia The aim of the present study was to investigate the impact of short-term creatine supplementation on cardiac and vascular health in older adults. METHODS: Males between the ages of 55-80 were randomly assigned to three groups: creatine, placebo and control. Creatine or placebo was provided for 7-day supplementation, at a dose of 20 g/day. Testing was performed at the same time of the day at baseline and on the eighth day. Vascular responses were assessed using an arterial pulse wave velocity equipment, while cardiac assessment was performed using an impedance cardiography device. RESULTS: The placebo group was older (71.1 ± 8.2 yr) compared to creatine (61.4 ± 5.2 yr) and control (62.5 ± 7.1 yr). Cardio-ankle vascular index improved just in the creatine group (8.7 ± 0.5 to 8.2 ± 0.5, p = 0.03). While the upstroke time of the placebo and control groups did not change after 7 days, the creatine group had a nonsignificant reduction, 178.9 ± 26.5 ms to 158.4 ± 28.6 ms, p = 0.07. Similar tendency was seen with the systolic blood pressures, while the placebo and control did not change, the creatine group showed nonsignificant improvement, especially on the right, 144.0 ± 12.7 mmHg to 136.1 ± 13.4 mmHg, p = 0.08. All three groups had similar responses in stroke volume (p = 0.61), contractility index (p = 0.64) and ejection fraction (p = 0.72). CONCLUSIONS: In older adults, acute creatine supplementation can positively affect vascular parameters of arterial stiffness and atherosclerosis. Creatine supplementation has the potential to serve as a potent adjuvant in the management of CVD for older adults. CLINICAL TRIAL REGISTRATION: clinicaltrials.gov; ID: NCT05329480.


Assuntos
Creatina , Suplementos Nutricionais , Análise de Onda de Pulso , Humanos , Masculino , Creatina/administração & dosagem , Idoso , Pessoa de Meia-Idade , Idoso de 80 Anos ou mais , Método Duplo-Cego , Pressão Sanguínea/efeitos dos fármacos , Doenças Cardiovasculares , Rigidez Vascular/efeitos dos fármacos , Coração/efeitos dos fármacos
14.
J Robot Surg ; 17(2): 465-472, 2023 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-35781195

RESUMO

3D printing is a growing tool in surgical education to visualize and teach complex procedures. Previous studies demonstrating the usefulness of 3D models as teaching tools for partial nephrectomy used highly detailed models costing between $250 and 1000. We aimed to create thorough, inexpensive 3D models to accelerate learning for trainees and increase health literacy in patients. Patient-specific, cost-effective ($30-50) 3D models of the affected urologic structures were created using pre-operative imaging of 40 patients undergoing partial nephrectomy at Thomas Jefferson University Hospital (TJUH) between July 2020 and May 2021. Patients undergoing surgery filled out a survey before and after seeing the model to assess patient understanding of their kidney, pathophysiology, surgical procedure, and risks of surgery. Three urological residents, one fellow, and six attendings filled out separate surveys to assess their surgical plan and confidence before and after seeing the model. In a third survey, they ranked how much the model helped their comprehension and confidence during surgery. Patient understanding of all four subjects significantly improved after seeing the 3D model (P < 0.001). The urology residents (P < 0.001) and fellow (P < 0.001) reported significantly increased self-confidence after interacting with the model. Attending surgeon confidence increased significantly after seeing the 3D model (P < 0.01) as well. Cost-effective 3D models are effective learning tools and assist with the evaluation of patients presenting with renal masses, and increase patient, resident, and fellow understanding in partial nephrectomies. Further research should continue to explore the utility of inexpensive models in other urologic procedures.


Assuntos
Neoplasias Renais , Procedimentos Cirúrgicos Robóticos , Humanos , Neoplasias Renais/cirurgia , Procedimentos Cirúrgicos Robóticos/métodos , Educação de Pacientes como Assunto , Nefrectomia/métodos , Impressão Tridimensional
15.
PLoS Comput Biol ; 7(7): e1002120, 2011 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-21814508

RESUMO

Previous studies have shown that neurons within the vestibular nuclei (VN) can faithfully encode the time course of sensory input through changes in firing rate in vivo. However, studies performed in vitro have shown that these same VN neurons often display nonlinear synchronization (i.e. phase locking) in their spiking activity to the local maxima of sensory input, thereby severely limiting their capacity for faithful encoding of said input through changes in firing rate. We investigated this apparent discrepancy by studying the effects of in vivo conditions on VN neuron activity in vitro using a simple, physiologically based, model of cellular dynamics. We found that membrane potential oscillations were evoked both in response to step and zap current injection for a wide range of channel conductance values. These oscillations gave rise to a resonance in the spiking activity that causes synchronization to sinusoidal current injection at frequencies below 25 Hz. We hypothesized that the apparent discrepancy between VN response dynamics measured in in vitro conditions (i.e., consistent with our modeling results) and the dynamics measured in vivo conditions could be explained by an increase in trial-to-trial variability under in vivo vs. in vitro conditions. Accordingly, we mimicked more physiologically realistic conditions in our model by introducing a noise current to match the levels of resting discharge variability seen in vivo as quantified by the coefficient of variation (CV). While low noise intensities corresponding to CV values in the range 0.04-0.24 only eliminated synchronization for low (<8 Hz) frequency stimulation but not high (>12 Hz) frequency stimulation, higher noise intensities corresponding to CV values in the range 0.5-0.7 almost completely eliminated synchronization for all frequencies. Our results thus predict that, under natural (i.e. in vivo) conditions, the vestibular system uses increased variability to promote fidelity of encoding by single neurons. This prediction can be tested experimentally in vitro.


Assuntos
Modelos Neurológicos , Neurônios/fisiologia , Núcleos Vestibulares/citologia , Potenciais de Ação , Animais , Potenciais da Membrana , Dinâmica não Linear , Núcleos Vestibulares/fisiologia
16.
Urol Oncol ; 40(4): 161.e1-161.e7, 2022 04.
Artigo em Inglês | MEDLINE | ID: mdl-34465541

RESUMO

PURPOSE: Robust prediction of progression on active surveillance (AS) for prostate cancer can allow for risk-adapted protocols. To date, models predicting progression on AS have invariably used traditional statistical approaches. We sought to evaluate whether a machine learning (ML) approach could improve prediction of progression on AS. PATIENTS AND METHODS: We performed a retrospective cohort study of patients diagnosed with very-low or low-risk prostate cancer between 1997 and 2016 and managed with AS at our institution. In the training set, we trained a traditional logistic regression (T-LR) classifier, and alternate ML classifiers (support vector machine, random forest, a fully connected artificial neural network, and ML-LR) to predict grade-progression. We evaluated model performance in the test set. The primary performance metric was the F1 score. RESULTS: Our cohort included 790 patients. With a median follow-up of 6.29 years, 234 developed grade-progression. In descending order, the F1 scores were: support vector machine 0.586 (95% CI 0.579 - 0.591), ML-LR 0.522 (95% CI 0.513 - 0.526), artificial neural network 0.392 (95% CI 0.379 - 0.396), random forest 0.376 (95% CI 0.364 - 0.380), and T-LR 0.182 (95% CI 0.151 - 0.185). All alternate ML models had a significantly higher F1 score than the T-LR model (all p <0.001). CONCLUSION: In our study, ML methods significantly outperformed T-LR in predicting progression on AS for prostate cancer. While our specific models require further validation, we anticipate that a ML approach will help produce robust prediction models that will facilitate individualized risk-stratification in prostate cancer AS.


Assuntos
Neoplasias da Próstata , Conduta Expectante , Humanos , Modelos Logísticos , Aprendizado de Máquina , Masculino , Neoplasias da Próstata/diagnóstico , Estudos Retrospectivos
17.
ISME Commun ; 2(1): 9, 2022 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-37938691

RESUMO

The symbiont-associated (SA) environmental package is a new extension to the minimum information about any (x) sequence (MIxS) standards, established by the Parasite Microbiome Project (PMP) consortium, in collaboration with the Genomics Standard Consortium. The SA was built upon the host-associated MIxS standard, but reflects the nestedness of symbiont-associated microbiota within and across host-symbiont-microbe interactions. This package is designed to facilitate the collection and reporting of a broad range of metadata information that apply to symbionts such as life history traits, association with one or multiple host organisms, or the nature of host-symbiont interactions along the mutualism-parasitism continuum. To better reflect the inherent nestedness of all biological systems, we present a novel feature that allows users to co-localize samples, to nest a package within another package, and to identify replicates. Adoption of the MIxS-SA and of the new terms will facilitate reports of complex sampling design from a myriad of environments.

18.
PhytoKeys ; 174: 165-194, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33776529

RESUMO

The extensive diversity of the tribe Orobancheae, the most species-rich lineage of holoparasitic Orobanchaceae, is concentrated in the Caucasus and Mediterranean regions of the Old World. This extant diversity has inspired hypotheses that these regions are also centres of origin of its key lineages, however the ability to test hypotheses has been limited by a lack of sampling and phylogenetic information about the species, especially in the Caucasus region. First, we assessed the phylogenetic relationships of several poorly known, problematic, or newly described species and host-races of four genera of Orobancheae occurring in the Caucasus region-Cistanche, Phelypaea, Phelipanche and Orobanche-using nuclear ribosomal (ITS) and plastid (trnL-trnF) sequence data. Then we applied a probablistic dispersal-extinction-cladogenesis model of historical biogeography across a more inclusive clade of holoparasites, to explicitly test hypotheses of Orobancheae diversification and historical biogeography shifts. In sum, we sampled 548 sequences (including 196 newly generated) from 13 genera, 140 species, and 175 taxa across 44 countries. We find that the Western Asia (particularly the Caucasus) and the Mediterranean are the centre of origin for large clades of holoparasitic Orobancheae within the last 6 million years. In the Caucasus, the centres of diversity are composed both of long-branch taxa and shallow, recently diversified clades, while Orobancheae diversity in the Mediterranean appears to represent mainly recent diversification.

19.
Urology ; 155: 101-109, 2021 09.
Artigo em Inglês | MEDLINE | ID: mdl-34186134

RESUMO

OBJECTIVE: To assesses if active surveillance (AS) is an appropriate treatment modality for patients with intermediate risk (IR) prostate cancer (PCa) utilizing population-level data to compare the survival outcomes of men with low risk (LR) and IR PCa initially treated with AS, watchful waiting (WW) or active treatment (AT). METHODS: In total, 166,244 patients were initially identified in the surveillance, epidemiology, and end results database using biopsy Gleason grade group (GG) alone-GG1 and GG2. In total, 94,891 patients with GG1 and GG2 disease were further stratified by National Comprehensive Cancer Network risk categories-LR, favorable IR (fIR), and unfavorable IR (uIR). Predictors of cancer-specific (CSS) and overall survival (OS) were analyzed, stratified by risk classification and initial treatment-AT (first-line curative surgery or radiotherapy), AS or WW, utilizing the new "Watchful waiting recode (2010+)" variable. RESULTS: We found GG2 patients on AS had worse CSS and OS than GG2 patients who received AT and GG1 patients treated with AS or AT; these trends persist within the National Comprehensive Cancer Network fIR and uIR cohorts. WW patients (GG1, GG2, LR, fIR, and uIR) had the worst survival outcomes of any cohort (log-rank tests P < .05). CONCLUSIONS: We demonstrate a significantly worse 5-year CSS and OS for men with GG2, fIR, and uIR PCa treated with AS compared to AT. Our analysis suggests that AS should not be the preferred treatment modality for IR PCa.


Assuntos
Neoplasias da Próstata/mortalidade , Neoplasias da Próstata/patologia , Conduta Expectante , Idoso , Humanos , Masculino , Pessoa de Meia-Idade , Gradação de Tumores , Medição de Risco , Programa de SEER , Estados Unidos/epidemiologia
20.
J Shoulder Elbow Surg ; 18(5): 804-7, 2009.
Artigo em Inglês | MEDLINE | ID: mdl-19362860

RESUMO

BACKGROUND: The purpose of this study was to identify characteristics associated with bilateral ruptures of the distal biceps tendons. METHODS: We present a retrospective case series of 25 patients who sustained non-simultaneous bilateral distal biceps brachii tendon ruptures that were repaired surgically, with follow-up available on 10 patients. The average age of the patients was 50 years (range 28-76). All patients were male. The mean time from the first tendon rupture to the contralateral tendon rupture was 2.7 years (range 0.5 - 6.3). Follow-up averaged 45 months (range 24-85). RESULTS: Patients with bilateral ruptures tended to be middle-aged men, who commonly participated in weight lifting, manual labor, or sports, and who had higher rates of nicotine (50%) and anabolic steroid use (20%) than the general population. After surgical repair of 9 of 10 patients, patients with bilateral distal biceps tendon ruptures had good to excellent outcomes. With the numbers available, outcomes were not statistically associated with manual labor, past medical history, prescription medications, prior tendon injury, body mass index, current activity in sports, use of nutritional supplements, or anabolic steroid use, although worker's compensation claims approached statistical significance (p = 0.059). CONCLUSIONS: Patients who sustained bilateral distal biceps tendon ruptures tended to be middle-aged men with higher rates of nicotine and anabolic steroid use than the general population.


Assuntos
Procedimentos Ortopédicos/métodos , Traumatismos dos Tendões/patologia , Traumatismos dos Tendões/cirurgia , Adulto , Idoso , Traumatismos do Braço/diagnóstico por imagem , Traumatismos do Braço/epidemiologia , Traumatismos do Braço/cirurgia , Estudos de Coortes , Articulação do Cotovelo/cirurgia , Humanos , Incidência , Escala de Gravidade do Ferimento , Masculino , Pessoa de Meia-Idade , Força Muscular/fisiologia , Músculo Esquelético/fisiopatologia , Músculo Esquelético/cirurgia , Cuidados Pós-Operatórios/métodos , Prognóstico , Radiografia , Recuperação de Função Fisiológica , Estudos Retrospectivos , Medição de Risco , Ruptura/epidemiologia , Ruptura/cirurgia , Traumatismos dos Tendões/diagnóstico por imagem , Traumatismos dos Tendões/epidemiologia , Resultado do Tratamento , Lesões no Cotovelo
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