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The intrusion of relatively warm water onto the continental shelf is widely recognized as a threat to Antarctic ice shelves and glaciers grounded below sea level, as enhanced ocean heat increases their basal melt. While the circulation of warm water has been documented on the East Antarctic continental shelf, the modes of warm water transport from the deep ocean onto the shelf are still uncertain. This makes predicting the future responses of major East Antarctic marine-grounded glaciers, such as Totten and Ninnis glaciers, particularly challenging. Here, we outline the key role of submarine canyons to convey southward flowing currents that transport warm Circumpolar Deep Water toward the East Antarctic shelf break, thus facilitating warm water intrusion on the continental shelf. Sediment drifts on the eastern flank of the canyons provide evidence for sustained southward-directed flows. These morpho-sedimentary features thus highlight areas potentially prone to enhanced ocean heat transport toward the continental shelf, with repercussions for past, present, and future glacial melting and consequent sea level rise.
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BACKGROUND: The role of intravenous fosfomycin (iv-FOS) as a part of combination therapy for Gram-negative bacteria bloodstream infections (GNB-BSI) needs to be evaluated in clinical practice, as in vitro data show potential efficacy. METHODS: All consecutive patients with a GNB-BSI from 01 January 2021 to 01 April 2023 were included. Primary outcome was 30-day mortality. A Cox regression analysis was used to identify predictors of mortality; an inverse-probability of treatment-weighting (IPTW) analysis was also performed. RESULTS: Overall, 363 patients were enrolled: 211 (58%) males, with a median (q1-q3) age of 68 (57-78) years, and a median Charlson comorbidity index of 5 (3-7). At GNB-BSI onset, the median SOFA score was 5 (2-7) and 122 patients (34%) presented with septic shock. Pathogens were principally Klebsiella pneumoniae (42%), Escherichia coli (28%) and Pseudomonas aeruginosa (17%); of them, 36% were carbapenem-resistant. The therapy included carbapenems (40%), cephalosporins (37%) and beta-lactams/beta-lactamases-inhibitors (19%); a combination with iv-FOS was used in 98 (27%) cases at a median dosage of 16 (16-18) g/daily. The use of iv-FOS was not associated with reduced crude mortality (21% vs 29%, P = 0.147). However, on multivariable Cox-regression, combination therapy with iv-FOS resulted in protection for mortality (aHR 0.51, 95% CI 0.28-0.92), but not other combo-therapies (HR 0.69, 95% CI 0.44-1.16). This result was also confirmed with the IPTW-adjusted Cox model (aHR 0.52, 95% CI 0.31-0.91). Subgroup analysis suggested a benefit in severe infections (SOFA > 6, PITT ≥ 4) and when iv-FOS was initiated within 24 hours of GNB-BSI onset. CONCLUSIONS: Fosfomycin in combination therapy for GNB-BSI may have a role in improving survival. These results justify the development of further clinical trials.
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Administração Intravenosa , Antibacterianos , Bacteriemia , Fosfomicina , Infecções por Bactérias Gram-Negativas , Pontuação de Propensão , Humanos , Fosfomicina/uso terapêutico , Fosfomicina/administração & dosagem , Masculino , Pessoa de Meia-Idade , Feminino , Idoso , Estudos Retrospectivos , Infecções por Bactérias Gram-Negativas/tratamento farmacológico , Infecções por Bactérias Gram-Negativas/mortalidade , Infecções por Bactérias Gram-Negativas/microbiologia , Antibacterianos/uso terapêutico , Antibacterianos/administração & dosagem , Bacteriemia/tratamento farmacológico , Bacteriemia/microbiologia , Bacteriemia/mortalidade , Bactérias Gram-Negativas/efeitos dos fármacos , Quimioterapia CombinadaRESUMO
High School students, recognized as a high-risk group for sexually transmitted infections (STIs), were the focal point of an educational campaign in Southern Italy to share information and good practices about STIs and HIV/AIDS. A baseline survey comprising 76 items was conducted via the REDCap platform to assess students' initial knowledge, attitudes, and practices (KAP) related to STIs and HIV/AIDS. Sociodemographic variables were also investigated. The association between variables and KAP score was assessed by Kruskal-Wallis' or Spearman's test, as appropriate. An ordinal regression model was built to estimate the effect size, reported as odds ratio (OR) with a 95% confidence interval (CI), for achieving higher KAP scores among students features. On a scale of 0 to 29, 1702 participants achieved a median KAP score of 14 points. Higher scores were predominantly reported by students from classical High Schools (OR 3.19, 95% C.I. 1.60-6.33, p<0.001). Additionally, elevated scores were associated with sexually active students (OR 1.48, 95% C.I. 1.12-1.96, p = 0.01), those vaccinated against Human Papilloma Virus (OR 2.47, 95% C.I. 1.89-3.24, p<0.001), those who had used emergency contraception (OR 1.56, 95% C.I. 1.09-2.24, p = 0.02, Table 2) and those obtaining information from TikTok (OR 1.62, 95% C.I. 1.14-2.30, p = 0.01). Conversely, being heterosexual was associated with an overall lower score (OR 0.48, 95% C.I. 0.32-0.73, p<0.001). High School students, often due to early sexual debut, seek information about HIV and STIs independently using social channels. However, the overall level of knowledge, attitudes, and practices remains low. Urgent school-based interventions are needed for this age group.
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Síndrome da Imunodeficiência Adquirida , Infecções por HIV , Infecções Sexualmente Transmissíveis , Humanos , Síndrome da Imunodeficiência Adquirida/prevenção & controle , Estudos Transversais , Conhecimentos, Atitudes e Prática em Saúde , Infecções Sexualmente Transmissíveis/epidemiologia , Infecções Sexualmente Transmissíveis/prevenção & controle , Comportamento Sexual , Inquéritos e Questionários , Estudantes , Infecções por HIV/epidemiologia , Infecções por HIV/prevenção & controleRESUMO
(1) Introduction: Since May 2021, sotrovimab has been available in Italy for early treatment of SARS-CoV-2 infection and to prevent disease progression. However, some in vitro studies have questioned its efficacy on Omicron variants. Therefore, we aim to further investigate the efficacy of sotrovimab in real-life settings. (2) Methods: We conducted a retrospective study collecting medical records of people with SARS-CoV-2 infection evaluated in the infectious diseases units of Sassari, Foggia, and Bari, Italy. We included people with SARS-CoV-2 infection treated with sotrovimab and people who did not receive any treatment in 2022. The primary study outcome was to evaluate the efficacy of sotrovimab in reducing disease progression (defined as the necessity of starting oxygen supplementation) and COVID-19-related death. The secondary outcome was to evaluate the safety of sotrovimab. (3) Results: We included 689 people; of them, 341 were treated with sotrovimab, while 348 did not receive any treatment. Overall, we registered 161 (23.4%) disease progressions and 65 (9.4%) deaths, with a significant difference between treated and not-treated people (p < 0.001). In the multivariate logistic regression, increasing age [OR for ten years increasing age 1.23 (95%CI 1.04-1.45)] was associated with a higher risk of disease progression. In addition, cardiovascular disease [OR 1.69 (1.01-2.80), fever [OR 3.88 (95%CI 2.35-6.38)], and dyspnea [OR 7.24 (95%CI 4.17-12.58)] were associated with an increased risk of disease progression. In contrast, vaccination [OR 0.21 (95%CI 0.12-0.37)] and sotrovimab administration [OR 0.05 (95%CI 0.02-0.11)] were associated with a lower risk of developing severe COVID-19. Regarding mortality, people with older age [OR for ten years increasing age 1.36 (95%CI 1.09-1.69)] had a higher risk of death. In addition, in the multivariate analysis, cardiovascular disease lost statistical significance, while people on chemotherapy for haematological cancer [OR 4.07 (95%CI 1.45-11.4)] and those with dyspnea at diagnosis [OR 3.63 (95%CI 2.02-6.50)] had an increased risk of death. In contrast, vaccination [OR 0.37 (95%CI 0.20-0.68)] and sotrovimab treatment [OR 0.16 (95%CI 0.06-0.42)] were associated with lower risk. Only two adverse events were reported; one person complained of diarrhoea a few hours after sotrovimab administration, and one had an allergic reaction with cutaneous rash and itching. (4) Conclusions: Our study showed that sotrovimab treatment was associated with a reduction of the risk of disease progression and death in SARS-CoV-2-infected people, 70% of whom were over 65 years and a with high vaccination rate, with excellent safety. Therefore, our results reinforce the evidence about the efficacy and safety of sotrovimab during the Omicron era in a real-world setting.
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COVID-19 , Doenças Cardiovasculares , Humanos , Criança , Lactente , SARS-CoV-2 , Estudos Retrospectivos , Progressão da Doença , DispneiaRESUMO
In respiratory infections, anemia is both a consequence of acute inflammation and a predictor of poor clinical outcomes. There are few studies investigating the role of anemia in COVID-19, suggesting a potential role in predicting disease severity. In this study, we aimed to assess the association between the presence of anemia at admission and incidence of severe disease and death in patients hospitalized for COVID-19. Data from all adult patients admitted for COVID-19 in University Hospital "P. Giaccone" Palermo, and University Hospital of Bari, Italy, were retrospectively collected from 1st of September 2020 to 31 August 2022. The association between anemia (defined as Hb < 13 g/dl and < 12 g/dl in males and females, respectively), in-hospital mortality and severe COVID-19 was tested using a Cox's regression analysis. Severe COVID-19 forms were defined as admission to intensive or sub-intensive care unit or a qSOFAscore ≥ 2 or CURB65scores ≥ 3. p values were calculated using the Student's t test for continuous variables and the Mantel-Haenszel Chi-square test for categorical ones. The association between anemia and the mortality was made using a Cox's regression analysis, adjusted, in two models, for the potential confounders and using a propensity score. Among the 1562 patients included in the analysis, prevalence of anemia was 45.1% (95% CI 43-48%). Patients with anemia were significantly older (p < 0.0001), reported more co-morbidities, and presented higher baseline levels of procalcitonin, CRP, ferritin and IL-6. Overall, the crude incidence of mortality was about four times higher in patients with anemia compared to those without. After adjusting for 17 potential confounders, the presence of anemia significantly increased the risk of death (HR = 2.68; 95% CI: 1.59-4.52) and of risk of severe COVID-19 (OR = 2.31; 95% CI: 1.65-3.24). The propensity score analysis substantially confirmed these analyses. Our study provides evidence that, in patients hospitalized for COVID-19, anemia is both associated with a more pronounced baseline pro-inflammatory profile and higher incidence of in-hospital mortality and severe disease.
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Anemia , COVID-19 , Masculino , Adulto , Feminino , Humanos , COVID-19/complicações , Estudos Retrospectivos , Anemia/epidemiologia , Fatores de Risco , Progressão da DoençaRESUMO
Antarctica's continental margins pose an unknown submarine landslide-generated tsunami risk to Southern Hemisphere populations and infrastructure. Understanding the factors driving slope failure is essential to assessing future geohazards. Here, we present a multidisciplinary study of a major submarine landslide complex along the eastern Ross Sea continental slope (Antarctica) that identifies preconditioning factors and failure mechanisms. Weak layers, identified beneath three submarine landslides, consist of distinct packages of interbedded Miocene- to Pliocene-age diatom oozes and glaciomarine diamicts. The observed lithological differences, which arise from glacial to interglacial variations in biological productivity, ice proximity, and ocean circulation, caused changes in sediment deposition that inherently preconditioned slope failure. These recurrent Antarctic submarine landslides were likely triggered by seismicity associated with glacioisostatic readjustment, leading to failure within the preconditioned weak layers. Ongoing climate warming and ice retreat may increase regional glacioisostatic seismicity, triggering Antarctic submarine landslides.
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INTRODUCTION: Remdesivir (REM) and monoclonal antibodies (mAbs) could alleviate severe COVID-19 in at-risk outpatients. However, data on their use in hospitalized patients, particularly in elderly or immunocompromised hosts, are lacking. METHODS: All consecutive patients hospitalized with COVID-19 at our unit from 1 July 2021 to 15 March 2022 were retrospectively enrolled. The primary outcome was the progression to severe COVID-19 (P/F < 200). Descriptive statistics, a Cox univariate-multivariate model, and an inverse probability treatment-weighted (IPTW) analysis were performed. RESULTS: Overall, 331 subjects were included; their median (q1-q3) age was 71 (51-80) years, and they were males in 52% of the cases. Of them, 78 (23%) developed severe COVID-19. All-cause in-hospital mortality was 14%; it was higher in those with disease progression (36% vs. 7%, p < 0.001). REM and mAbs resulted in a 7% (95%CI = 3-11%) and 14% (95%CI = 3-25%) reduction in the risk of severe COVID-19, respectively, after adjusting the analysis with the IPTW. In addition, by evaluating only immunocompromised hosts, the combination of REM and mAbs was associated with a significantly lower incidence of severe COVID-19 (aHR = 0.06, 95%CI = 0.02-0.77) when compared with monotherapy. CONCLUSIONS: REM and mAbs may reduce the risk of COVID-19 progression in hospitalized patients. Importantly, in immunocompromised hosts, the combination of mAbs and REM may be beneficial.
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COVID-19 , Idoso , Masculino , Humanos , Idoso de 80 Anos ou mais , Feminino , Estudos Retrospectivos , Tratamento Farmacológico da COVID-19 , Anticorpos Monoclonais/uso terapêutico , Anticorpos Neutralizantes , Hospedeiro Imunocomprometido , Progressão da DoençaRESUMO
Migrant populations are more susceptible to viral hepatitis and HIV due to the epidemiology from their country of origin or their social vulnerability when they arrive in Europe. The aims of the study are to explore the incidence of HIV and HCV in low-wage agricultural migrant workers and their knowledge, attitude, and practice with regard to HIV and HCV, as well as their sexual behaviour and risk factors. As part of the mobile clinic services, we performed a screening campaign for HIV-HCV involving migrants living in three Apulian establishments. Results: Between January 2020 and April 2021, 309 migrants (n. 272, 88% male, mean age 28.5 years) were enrolled in the study. Most of the migrants interviewed (n = 297, 96%) reported a stopover in Libya during their trip to Italy. Only 0.9% (n. 3) of migrants reported having been tested for HCV, while 30.7% (n. 95) reported being tested for HIV. Furthermore, screening tests found four migrants (1.3%) to be HIV positive and nine (2.9%) to be HCV positive. The median knowledge score was 1 (IQR 0-3; maximum score: 6 points) for HCV and 3 (IQR 1-4; maximum score: 7 points) for HIV and low use of condoms was 5% (n. 16), while more than 95% show an attitude score of 5 (IQR 5-6; maximum score:6 points) on HIV-HCV education campaigns. In a multivariate analysis, being male (OR = 1.72; 95% CI 1.28−1.92), being single (OR = 1.63; 95% CI 1.20−2.03), being of low educational status (OR = 2.09; 95% CI 1.29−2.21), living in shantytowns for >12 months (OR = 1.95; 95% CI 1.25−2.55), and originating from the African continent (OR = 1.43; 95% CI 1.28−2.01) are significant predictors of poor knowledge on HCV. Our data show low knowledge, especially of HCV, confirming migrants as a population with a higher risk of infection. To develop education programmes, integrated care and screening among migrants could be an effective strategy, considering the high attitude toward these items shown in our study.
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Infecções por HIV , Hepatite C , Migrantes , Masculino , Humanos , Adulto , Feminino , Infecções por HIV/prevenção & controle , Estudos Transversais , Áreas de Pobreza , Incidência , Itália/epidemiologia , Hepatite C/epidemiologiaRESUMO
BACKGROUND: To date, there is a scarcity of information and literature on Macaca maura health status relative to viral diseases. The objectives of the present study were to investigate on the potential spread of enteric and non-enteric viruses shed in the environment through a wild macaque feces and to understand the possible interrelation in the spread of zoonotic viruses in a poorly studied geographical area, the Sulawesi Island. This study will also contribute providing useful information on potential threats to the health of this endangered species. METHODS: The sampling was conducted between 2014 and 2016 in the Bantimurung Bulusaraung National Park, in the south of the Sulawesi Island and non-invasive sampling methods were used to collect fresh stools of the M. maura, one of the seven macaque species endemic to the island of Sulawesi, Indonesia. The population under study consisted in two wild, neighboring social macaque groups with partially overlapping home ranges; twenty-four samples were collected and examined using negative staining electron microscopy and a panel of PCR protocols for the detection of ten RNA and two DNA viruses. RESULTS: Viral particles resembling parvovirus (5 samples), picornavirus (13 samples) and calicivirus (13 samples) were detected by electron microscopy whereas the PCR panel was negative for the 12 viruses investigated, except for one sample positive for a mosquito flavivirus. The results did not correlate with animal sex; furthermore, because all of the animals were clinically healthy, it was not possible to correlate feces consistency with viral presence. CONCLUSIONS: As information on viral infections in wild moor macaques remains limited, further studies are yet required to identify the fecal-oral and blood transmitted potentially zoonotic viruses, which may infect the moor macaque and other macaque species endemic to the South Sulawesi Island.
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Macaca , Picornaviridae , Animais , Zoonoses , FezesRESUMO
The Southern Ocean surrounding Antarctica is a region that is key to a range of climatic and oceanographic processes with worldwide effects, and is characterised by high biological productivity and biodiversity. Since 2013, the International Bathymetric Chart of the Southern Ocean (IBCSO) has represented the most comprehensive compilation of bathymetry for the Southern Ocean south of 60°S. Recently, the IBCSO Project has combined its efforts with the Nippon Foundation - GEBCO Seabed 2030 Project supporting the goal of mapping the world's oceans by 2030. New datasets initiated a second version of IBCSO (IBCSO v2). This version extends to 50°S (covering approximately 2.4 times the area of seafloor of the previous version) including the gateways of the Antarctic Circumpolar Current and the Antarctic circumpolar frontal systems. Due to increased (multibeam) data coverage, IBCSO v2 significantly improves the overall representation of the Southern Ocean seafloor and resolves many submarine landforms in more detail. This makes IBCSO v2 the most authoritative seafloor map of the area south of 50°S.
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Since May 2022, the monkeypox (MPX) virus has represented an emerging issue due to outbreaks in non-endemic areas. This report presents the first case of paraphimosis caused by an MPX infection during the outbreak. The patient accessed the emergency department for a sudden onset of swelling of the penis and paraphimosis caused by MPX lesions that brought about stenosis of the foreskin. He therefore underwent a dorsal slit procedure with resolution. No antiviral therapy was required. A multidisciplinary approach should be preferred for the management of MPX, due to the possibility of uncommon and disseminated presentations.
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An amendment to this paper has been published and can be accessed via a link at the top of the paper.
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The aim of this study was to determine the prevalence of Shiga toxin-producing Escherichia coli in fresh beef marketed in 2017 in 13 regions of Italy, to evaluate the potential risk to human health. According to the ISO/TS 13136:2012 standard, 239 samples were analysed and nine were STEC positive, from which 20 strains were isolated. The STEC-positive samples were obtained from Calabria (n = 1), Campania (n = 1), Lazio (n = 2), Liguria (n = 1), Lombardia (n = 1) and Veneto (n = 3). All STEC strains were analysed for serogroups O26, O45, O55, O91, O103, O104, O111, O113, O121, O128, O145, O146 and O157, using Real-Time PCR. Three serogroups were identified amongst the 20 strains: O91 (n = 5), O113 (n = 2), and O157 (n = 1); the O-group for each of the 12 remaining STEC strains was not identified. Six stx subtypes were detected: stx1a, stx1c, stx2a, stx2b, stx2c and stx2d. Subtype stx2c was the most common, followed by stx2d and stx2b. Subtype stx2a was identified in only one eae-negative strain and occurred in combination with stx1a, stx1c and stx2b. The presence in meat of STEC strains being potentially harmful to human health shows the importance, during harvest, of implementing additional measures to reduce contamination risk.
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Over the past 34 Million years, the Antarctic continental shelf has gradually deepened due to ice sheet loading, thermal subsidence, and erosion from repeated glaciations. The deepening that is recorded in the sedimentary deposits around the Antarctic margin indicates that after the mid-Miocene Climate Optimum (≈15 Ma), Antarctic Ice Sheet (AIS) dynamical response to climate conditions changed. We explore end-members for maximum AIS extent, based on ice-sheet simulations of a late-Pleistocene and a mid-Miocene glaciation. Fundamental dynamical differences emerge as a consequence of atmospheric forcing, eustatic sea level and continental shelf evolution. We show that the AIS contributed to the amplification of its own sensitivity to ocean forcing by gradually expanding and eroding the continental shelf, that probably changed its tipping points through time. The lack of past topographic and bathymetric reconstructions implies that so far, we still have an incomplete understanding of AIS fast response to past warm climate conditions, which is crucial to constrain its future evolution.
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The original version of this Article contained an error in the spelling of the author Florence Colleoni, which was incorrectly given as Florence Colloni. This has been corrected in both the PDF and HTML versions of the Article.
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Understanding how the Antarctic ice sheet will respond to global warming relies on knowledge of how it has behaved in the past. The use of numerical models, the only means to quantitatively predict the future, is hindered by limitations to topographic data both now and in the past, and in knowledge of how subsurface oceanic, glaciological and hydrological processes interact. Incorporating the variety and interplay of such processes, operating at multiple spatio-temporal scales, is critical to modeling the Antarctic's system evolution and requires direct observations in challenging locations. As these processes do not observe disciplinary boundaries neither should our future research.
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Switching from one functional or cognitive operation to another is thought to rely on executive/control processes. The efficacy of these processes may depend on the extent of overlap between neural circuitry mediating the different tasks; more effective task preparation (and by extension smaller switch costs) is achieved when this overlap is small. We investigated the performance costs associated with switching tasks and/or switching sensory modalities. Participants discriminated either the identity or spatial location of objects that were presented either visually or acoustically. Switch costs between tasks were significantly smaller when the sensory modality of the task switched versus when it repeated. This was the case irrespective of whether the pre-trial cue informed participants only of the upcoming task, but not sensory modality (Experiment 1) or whether the pre-trial cue was informative about both the upcoming task and sensory modality (Experiment 2). In addition, in both experiments switch costs between the senses were positively correlated when the sensory modality of the task repeated across trials and not when it switched. The collective evidence supports the independence of control processes mediating task switching and modality switching and also the hypothesis that switch costs reflect competitive interference between neural circuits.
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Percepção Auditiva , Percepção Visual , Adulto , Análise de Variância , Sinais (Psicologia) , Discriminação Psicológica , Feminino , Humanos , Masculino , Tempo de Reação , Percepção Espacial , Análise e Desempenho de Tarefas , Adulto JovemRESUMO
Whether the somatosensory system, like its visual and auditory counterparts, is comprised of parallel functional pathways for processing identity and spatial attributes (so-called what and where pathways, respectively) has hitherto been studied in humans using neuropsychological and hemodynamic methods. Here, electrical neuroimaging of somatosensory evoked potentials (SEPs) identified the spatio-temporal mechanisms subserving vibrotactile processing during two types of blocks of trials. What blocks varied stimuli in their frequency (22.5 Hz vs. 110 Hz) independently of their location (left vs. right hand). Where blocks varied the same stimuli in their location independently of their frequency. In this way, there was a 2x2 within-subjects factorial design, counterbalancing the hand stimulated (left/right) and trial type (what/where). Responses to physically identical somatosensory stimuli differed within 200 ms post-stimulus onset, which is within the same timeframe we previously identified for audition (De Santis, L., Clarke, S., Murray, M.M., 2007. Automatic and intrinsic auditory "what" and "where" processing in humans revealed by electrical neuroimaging. Cereb Cortex 17, 9-17.). Initially (100-147 ms), responses to each hand were stronger to the what than where condition in a statistically indistinguishable network within the hemisphere contralateral to the stimulated hand, arguing against hemispheric specialization as the principal basis for somatosensory what and where pathways. Later (149-189 ms) responses differed topographically, indicative of the engagement of distinct configurations of brain networks. A common topography described responses to the where condition irrespective of the hand stimulated. By contrast, different topographies accounted for the what condition and also as a function of the hand stimulated. Parallel, functionally specialized pathways are observed across sensory systems and may be indicative of a computationally advantageous organization for processing spatial and identity information.
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Algoritmos , Mapeamento Encefálico/métodos , Encéfalo/fisiologia , Eletroencefalografia/métodos , Potenciais Somatossensoriais Evocados/fisiologia , Vias Neurais/fisiologia , Tato/fisiologia , Adulto , Diagnóstico por Imagem/métodos , Feminino , Humanos , MasculinoRESUMO
The auditory system includes 2 parallel functional pathways-one for treating sounds' identities and another for their spatial attributes (so-called "what" and "where" pathways). We examined the spatiotemporal mechanisms along auditory "what" and "where" pathways and whether they are automatically engaged in differentially processing spatial and pitch information of identical stimuli. Electrical neuroimaging of auditory evoked potentials (i.e., statistical analyses of waveforms, field strength, topographies, and source estimations) was applied to a passive "oddball" paradigm comprising 2 varieties of blocks of trials. On "what" blocks, band-pass-filtered noises varied in pitch, independently of perceived location. On "where" blocks, the identical stimuli varied in perceived location independently of pitch. Beginning 100 ms poststimulus, the electric field topography significantly differed between conditions, indicative of the automatic recruitment of distinct intracranial generators. A distributed linear inverse solution and statistical analysis thereof revealed activations within superior temporal cortex and prefrontal cortex bilaterally that were common for both conditions, as well as regions within the right temporoparietal cortices that were selective for the "where" condition. These findings support models of automatic and intrinsic parallel processing of auditory information, such that segregated processing of spatial and pitch features may be an organizing principle of auditory function.
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Percepção Auditiva/fisiologia , Localização de Som/fisiologia , Percepção Espacial/fisiologia , Estimulação Acústica , Adulto , Vias Auditivas/fisiologia , Mapeamento Encefálico , Interpretação Estatística de Dados , Eletroencefalografia , Campos Eletromagnéticos , Potenciais Evocados Auditivos/fisiologia , Feminino , Humanos , Modelos Lineares , Masculino , Percepção da Altura Sonora/fisiologia , Córtex Pré-Frontal/fisiologia , Lobo Temporal/fisiologiaRESUMO
In this paper, we report the identification of genes from pine (PpAAT), Arabidopsis (AtAAT) and rice (OsAAT) encoding a novel class of aspartate aminotransferase (AAT, EC 2.6.1.1) in plants. The enzyme is unrelated to other eukaryotic AATs from plants and animals but similar to bacterial enzymes. Phylogenetic analysis indicates that this prokaryotic-type AAT is closely related to cyanobacterial enzymes, suggesting it might have an endosymbiotic origin. Interestingly, most of the essential residues involved in the interaction with the substrate and the attachment of pyridoxal phosphate cofactor in the active site of the enzyme were conserved in the deduced polypeptide. The polypeptide is processed in planta to a mature subunit of 45 kDa that is immunologically distinct from the cytosolic, mitochondrial and chloroplastic isoforms of AAT previously characterized in plants. Functional expression of PpAAT sequences in Escherichia coli showed that the processed precursor is assembled into a catalytically active homodimeric holoenzyme that is strictly specific for aspartate. These atypical genes are predominantly expressed in green tissues of pine, Arabidopsis and rice, suggesting a key role of this AAT in nitrogen metabolism associated with photosynthetic activity. Moreover, immunological analyses revealed that the plant prokaryotic-type AAT is a nuclear-encoded chloroplast protein. This implies that two plastidic AAT co-exist in plants: a eukaryotic type previously characterized and the prokaryotic type described here. The respective roles of these two enzymes in plant amino acid metabolism are discussed.