512 research outputs found

    Methemoglobinemia Associated with Late-Onset Neonatal Sepsis: A Single-Center Experience

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    Objective â Methemoglobinemia (MetHb) is a rare congenital or acquired cause of infantile cyanosis. We examined the role of MetHb in a neonatal intensive care unit (NICU). Study Design â A retrospective observational study was conducted reviewing blood gas analyses of hospitalized newborns over a 2-year period. MetHb-positive patients (MetHb >1.8%) were matched with a control group for gestational age, weight, disease, and illness severity at admission. Maternal, neonatal, clinical, and laboratory parameters were collected and analyzed in both groups. Results â MetHb incidence was 6%. The mean MetHb in the case group was 7.2%, and the first positive samples were observed at a mean of 22 days of life, 6 days prior to clinical or culture-proven sepsis. We identified low maternal age (31 vs. 34 years; p = 0.038), sepsis (90 vs. 45%; p = 0.022), and protracted parenteral nutrition (46 vs. 23 days; p = 0.013) as risk factors for MetHb, and early minimal enteral feeding as protective factor (12th vs. 9th day; p = 0.038). Conclusion â MetHb has a high occurrence in NICU and can be a helpful prognostic indicator of an infectious process. Understanding and prompt identification of MetHb can allow pediatricians to implement a life-saving therapy

    Recognizable neonatal clinical features of aplasia cutis congenita

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    Background: Aplasia cutis congenita (ACC), classified in nine groups, is likely to be underreported, since milder isolated lesions in wellbeing newborns could often be undetected, and solitary lesions in the context of polymalformative syndromes could not always be reported. Regardless of form and cause, therapeutic options have in common the aim to restore the deficient mechanical and immunological cutaneous protection and to limit the risk of fluid leakage or rupture of the exposed organs. We aimed to review our institutional prevalence, comorbidities, treatment and outcome of newborns with ACC. Methods: We conducted a retrospective study including all newborns affected by ACC and admitted at the University Mother-Child Department from October 2010 to October 2019. Anthropometric and clinical characteristics of ACC1 versus a non-isolated ACC group were analyzed. Results: We encountered 37 newborns, 16 with ACC1 versus 21 with non-isolated ACC. The incidence rate of 0.1% in ACC1 was higher than expected, while 19% of cases showed intrafamilial autosomal dominant transmission. Higher birth weight centile, though lower than reference population, being adequate for gestational age, normal Apgar score and euglycemia characterizing ACC1 resulted associated to a rapid tissue regeneration. Non-isolated ACC, in relation to concomitant congenital anomalies and higher prematurity rate, showed more surgical and medical complications along with the risk of neonatal death. Specifically, newborns with ACC4 were characterized by the frequent necessity of abdominal wall defect repair, responsible for the occurrence of an abdominal compartment syndrome. Conclusion: Prompt carefully assessment of the newborn with ACC in order to exclude concomitant other congenital malformations, provides clues to the underlying pathophysiology, and to the short-term prognosis. Family should be oriented toward identification of other family members affected by similar pathology, while obstetric history should exclude initial multiple pregnancy with death of a co-twin, placental anomalies and drug assumption. Molecular-genetic diagnosis and genetic counseling are integrative in individualized disease approach

    Exploring the uncertainty in capacity estimation at roundabouts

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    Purpose In gap-acceptance theory the critical and the follow up headways have a significant role in determining roundabout entry capacities which in turn depend on circulating flow rates under a specified arrival headway distribution. Calculation considers single mean values of the gap-acceptance parameters, neglecting the inherent variations in these random variables and providing a single value of entry capacity. The purpose of this paper is to derive the entry capacity distribution which accounts for the variations of the contributing (random) variables and suggest how to consider this issue in the operational analysis of the roundabouts. Methods We performed a Monte Carlo simulation to get the distribution of entry capacity and found Crystal Ball software effective for performing the random sampling from the probability density functions of each contributing parameter. A steady-state model of capacity was used for performing many runs; in each run, the values of each contributing parameter were randomly drawn from the corresponding distributions. Results The paper presents the first simulations and the entry capacity distributions at roundabouts, once the probability distributions of the headways were assumed. The results of the analysis were expressed probabilistically, meaning that the probability distributions of capacity rather than the simple point estimates were obtained. Conclusions Comparing the capacity values based on a meta analytic estimation of critical and follow-up headways and the capacity functions based on the probability distributions of the model parameters, more insights in developing an appropriate approach to capacity estimation at roundabouts can be gained

    A Methodological Framework to Assess Road Infrastructure Safety and Performance Efficiency in the Transition toward Cooperative Driving

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    There is increasing interest in connected and automated vehicles (CAVs), since their implementation will transform the nature of transportation and promote social and economic change. Transition toward cooperative driving still requires the understanding of some key questions to assess the performances of CAVs and human-driven vehicles on roundabouts and to properly balance road safety and traffic efficiency requirements. In this view, this paper proposes a simulation-based methodological framework aiming to assess the presence of increasing proportions of CAVs on roundabouts operating at a high-capacity utilization level. A roundabout was identified in Palermo City, Italy, and built in Aimsun (version 20) to describe the stepwise methodology. The CAV-based curves of capacity by entry mechanism were developed and then used as target capacities. To calibrate the model parameters, the capacity curves were compared with the capacity data simulated by Aimsun. The impact on the safety and performance efficiency of a lane dedicated to CAVs was also examined using surrogate measures of safety. The paper ends with highlighting a general improvement with CAVs on roundabouts, and with providing some insights to assess the advantages of the automated and connected driving technologies in transitioning to smarter mobilit

    Nitric oxide does not inhibit but is metabolized by the cytochrome bcc-aa3 supercomplex

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    Nitric oxide (NO) is a well-known active site ligand and inhibitor of respiratory terminal oxidases. Here, we investigated the interaction of NO with a purified chimeric bcc-aa3 supercomplex composed of Mycobacterium tuberculosis cytochrome bcc and Mycobacterium smegmatis aa3-type terminal oxidase. Strikingly, we found that the enzyme in turnover with O2 and reductants is resistant to inhibition by the ligand, being able to metabolize NO at 25◦C with an apparent turnover number as high as ≈303 mol NO (mol enzyme)−1 min−1 at 30 µM NO. The rate of NO consumption proved to be proportional to that of O2 consumption, with 2.65 ± 0.19 molecules of NO being consumed per O2 molecule by the mycobacterial bcc-aa3. The enzyme was found to metabolize the ligand even under anaerobic reducing conditions with a turnover number of 2.8 ± 0.5 mol NO (mol enzyme)−1 min−1 at 25◦C and 8.4 µM NO. These results suggest a protective role of mycobacterial bcc-aa3 supercomplexes against NO stress

    2q13 microdeletion syndrome: Report on a newborn with additional features expanding the phenotype

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    We describe an additional newborn with craniofacial dysmorphisms, congenital heart disease, hypotonia, and a 2q13 deletion of 1.7 Mb. The clinical and genomic findings observed are consistent with the diagnosis of 2q13 microdeletion syndrome

    Bioenergetic relevance of hydrogen sulfide and the interplay between gasotransmitters at human cystathionine β-synthase

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    Merely considered as a toxic gas in the past, hydrogen sulfide (H2S) is currently viewed as the third ‘gasotransmitter’ in addition to nitric oxide (NO) and carbon monoxide (CO), playing a key signalling role in human (patho)physiology. H2S can either act as a substrate or, similarly to CO and NO, an inhibitor of mitochondrial respiration, in the latter case by targeting cytochrome c oxidase (CcOX). The impact of H2S on mitochondrial energy metabolism crucially depends on the bioavailability of this gaseous molecule and its interplay with the other two gasotransmitters. The H2S-producing human enzyme cystathionine β-synthase (CBS), sustaining cellular bioenergetics in colorectal cancer cells, plays a role in the interplay between gasotransmitters. The enzyme was indeed recently shown to be negatively modulated by physiological concentrations of CO and NO, particularly in the presence of its allosteric activator S-adenosyl-L-methionine (AdoMet). These newly discovered regulatory mechanisms are herein reviewed. This article is part of a Special Issue entitled ‘EBEC 2016: 19th European Bioenergetics Conference, Riva del Garda, Italy, July 2–6, 2016’, edited by Prof. Paolo Bernardi
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