Prognostic Markers in Pediatric Acute Liver Failure.

Introduction: Acute liver failure (ALF), although rare in children, is a complex progressive pathology, with multisystem involvement and high mortality. Isolated variables or those included in prognostic scores have been studied, to optimize organ allocation. However, its validation is challenging. This study aimed to assess the accuracy of several biomarkers and scores as predictors of prognosis in pediatric ALF (PALF). Methods: An observational study with retrospective data collection, including all cases of ALF, was defined according to the criteria of the Pediatric Acute Liver Failure Study Group, admitted to a pediatric intensive care unit (PICU) for 28 years. Two groups were defined: spontaneous recovery (SR) and non-SR (NSR) - submitted to liver transplantation (LT) or death at PICU discharge. Results: Fifty-nine patients were included, with a median age of 24 months, and 54% were female. The most frequent etiologies were metabolic (25.4%) and infectious (18.6%); 32.2% were undetermined. SR occurred in 21 patients (35.6%). In NSR group (N = 38, 64.4%), 25 required LT (42.4%) and 19 died (32.2%), 6 (15.7%) of whom after LT. The accuracy to predict NSR was acceptable for lactate at admission (AUC 0.72; 95% CI: 0.57-0.86; p = 0.006), ammonia peak (AUC 0.72; 95% CI: 0.58-0.86; p = 0.006), and INR peak (AUC 0.70; 95% CI: 0.56-0.85; p = 0.01). The cut-off value for lactate at admission was 1.95 mmol/L (sensitivity 78.4% and specificity 61.9%), ammonia peak was 64 µmol/L (sensitivity 100% and specificity 38.1%), and INR peak was 4.8 (sensitivity 61.1% and specificity 76.2%). Lactate on admission was shown to be an independent predictor of NSR on logistic regression model. Two prognostic scores had acceptable discrimination for NSR, LIU (AUC 0.73; 95% CI: 0.59-0.87; p = 0.004) and PRISM (AUC 0.71; 95% CI: 0.56-0.86; p = 0.03). In our study, the PALF delta score (PALF-ds) had lower discrimination capacity (AUC 0.63; 95% CI: 0.47-0.78; p = 0.11). Conclusions: The lactate at admission, an easily obtained parameter, had a similar capacity than the more complex scores, LIU and PRISM, to predict NSR. The prognostic value in our population of the promising dynamic score, PALF-ds, was lower than expected.

Introdução: A falência hepática aguda (FHA), apesar de rara em pediatria, é uma patologia complexa, com envolvimento multissistémico e elevada mortalidade. Têm sido estudadas variáveis isoladas ou incluídas em scores de prognóstico, com o objetivo de otimizar a alocação de órgãos. No entanto, a sua validação apresenta alguns desafios. O presente estudo tem como objetivo avaliar a precisão de vários biomarcadores e scores, como preditores de prognóstico na FHA. Métodos: Estudo observacional com método de colheita de dados retrospetivo, tendo como critérios de inclusão os casos de FHA, definida de acordo com os critérios da Pediatric Acute Liver Failure Study Group, admitidos numa Unidade de Cuidados Intensivos Pediátricos (UCIP) num período de 28 anos. Definiram-se 2 grupos: recuperação espontânea (RE) e sem recuperação espontânea (SRE) ­ doentes submetidos a transplante hepático (TRH) ou morte na alta da UCIP. Resultados: Incluíram-se 59 doentes, com mediana de idade de 24 meses, 54% do sexo feminino. As etiologias mais frequentes foram a metabólica (25.4%) e a infeciosa (18.6%); em 32.2% foi indeterminada. Apresentaram RE 21 doentes (35.6%). No grupo SRE (N = 38, 64.4%), 25 necessitaram de TRH (42.4%) e 19 faleceram (32.2%), dos quais 6 (15.7%) tinham sido submetidos a TRH. A precisão prognóstica para a ausência de recuperação espontânea foi aceitável para o lactato na admissão (AUC 0.72; IC 95%: 0.57­0.86; p = 0.006), amónia máxima (AUC 0.72; IC 95%: 0.58­0.86; p = 0.006) e INR máximo (AUC 0.70; IC 95%: 0.56­0.85; p = 0.01). O valor de cut-off do lactato na admissão foi de 1.95 mmol/L (sensibilidade 78.4% e especificidade 61.9%) e da amónia máxima foi de 64 umol/L (sensibilidade 100% e especificidade 38.1%). O lactato à admissão mostrou ser um fator independente para NSR, no modelo de regressão logística. Os scores LIU e PRISM apresentaram curvas ROC com aceitável capacidade de discriminação para a ausência de recuperação espontânea, com AUC de 0.73 (IC 95%: 0.59­0.87; p = 0.004) e 0.71 (IC 95%: 0.56­0.86; p = 0.03), respetivamente. No nosso estudo, o score PALF-Delta (PALF-ds) teve uma menor capacidade de discriminação (AUC 0.63; IC 95%: 0.47­0.78; p = 0.11). Conclusões: O lactato na admissão, um parâmetro de fácil obtenção, teve uma capacidade semelhante aos scores mais complexos, LIU e PRISM, para predizer a ausência de recuperação espontânea. O valor prognóstico nesta série, do promissor score dinâmico PALF-ds, foi inferior ao esperado.

Severe Influenza Virus and Respiratory Syncytial Virus Infections in Intensive Care Over the Last 15 Years.

INTRODUCTION: Influenza virus is a common agent of pediatric infections. Most cases are mild, but severe illness and death can occur. We aimed to analyze severe cases associated the influenza virus and compare it with respiratory syncytial virus (RSV). METHODS: This is a retrospective study of 0-17-year-old patients admitted to the intensive care unit (ICU) of Hospital Pediátrico, Centro Hospitalar e Universitário de Coimbra (Pediatric Hospital, Coimbra Hospital and University Center), a tertiary pediatric hospital in Coimbra, Portugal, over the last 15 years (2008-2022) due to influenza virus infection. Clinical presentation, severity, and evolution were analyzed. A comparison of children with RSV infection admitted in the same period was performed. RESULTS: We identified 47 cases of influenza virus infection (34% coinfection with other viruses), median age of 2.3 years (interquartile range (IQR) 6.1), and 38% had comorbidities. The median admissions were three/year (maximum 11 in 2019). Influenza A was identified in 96%. Ninety-six percent had respiratory symptoms, 38% had neurologic symptoms, and 28% had sepsis. The main reason for admission was respiratory failure (68%). The mean pediatric index of mortality 2 (PIM2) at admission was 9±15.9%. Ventilatory support was necessary in 66%, vasoactive support in 19%, and blood products in 17%. The median length of stay was four days (IQR 5). There were four (8.5%) deaths. During the same study period, there were 171 RSV-related admissions. When comparing influenza (group A, without RSV coinfection) and RSV (group B), the first had a higher PIM2 on admission, greater need of ventilatory support, more complications, and higher mortality (p=0.001). CONCLUSIONS: The number of influenza virus infections admitted to ICU was much lower than RSV. However, influenza was more severe and associated with all deaths registered.

The prognostic value of delta-lactate in critically ill children.

AIM: This study aimed to test delta-lactate (ΔL) as a short-term risk stratification method in critically ill children. METHODS: An exploratory study of patients admitted to paediatric intensive care unit (PICU) was conducted. ΔL was calculated as the difference between the maximum lactate concentrations on Days 1 and 2. According to the ΔL cutoff, two groups were considered: low mortality risk (LMR) - ΔL ≥ 0.05 mmol/L - and high mortality risk (HMR) - ΔL < 0.05 mmol/L. RESULTS: Mortality, both during PICU stay and at 28 days, was statistically associated with elevated serum lactate on D1 and D2, per se. For the 93 cases with elevated lactate on Day 1, and a ΔL cutoff of 0.05 mmol/L, the area under the ROC curve was 0.698 (95% confidence interval, 0.47-0.93). HMR patients scored higher PIM3, were not discharged home until 28 days, counted fewer ventilation-free days and needed renal replacement therapy more often. CONCLUSION: Elevated lactate levels at admission, as well as applying the optimal cutoff for ΔL, allowed to predict short-term mortality: if an increase or minimal decrease in lactate maximum levels occurred from D1 to D2, death was almost eight times more probable. In critically ill children, delta-lactate predicts short-term outcome.

Cardiovascular manifestations of type IV Ehlers-Danlos syndrome - A case report.

Type IV Ehlers-Danlos syndrome (vascular) is a rare connective tissue disease caused by COL3A1 gene mutation on type III collagen. Clinical presentation is related to vascular fragility and risk of rupture of the arterial wall. Definite diagnosis is given by genetic study and the approach to these patients requires a multidisciplinary team and effective blood pressure control. There is currently only one medication with potential benefit in prevention of cardiovascular events: celiprolol. This article describes the case of a 41-year-old female patient, diagnosed with vascular Ehlers-Danlos syndrome after multiple major cardiovascular events: aortic, coronary and carotid dissections and venous and arterial thrombosis. These required multiple surgical interventions and long-term admission in intensive care units leading to complete functional recovery. This case report seeks to stress the need for an early diagnosis to prevent the severe cardiovascular complications of this rare syndrome.

foxm1 Modulates Cell Non-Autonomous Response in Zebrafish Skeletal Muscle Homeostasis.

foxm1 is a master regulator of the cell cycle, contributing to cell proliferation. Recent data have shown that this transcription factor also modulates gene networks associated with other cellular mechanisms, suggesting non-proliferative functions that remain largely unexplored. In this study, we used CRISPR/Cas9 to disrupt foxm1 in the zebrafish terminally differentiated fast-twitching muscle cells. foxm1 genomic disruption increased myofiber death and clearance. Interestingly, this contributed to non-autonomous satellite cell activation and proliferation. Moreover, we observed that Cas9 expression alone was strongly deleterious to muscle cells. Our report shows that foxm1 modulates a muscle non-autonomous response to myofiber death and highlights underreported toxicity to high expression of Cas9 in vivo.

[Prognostic value of near-infrared spectroscopy in hypoxic-ischaemic encephalopathy]. / Valor pronóstico de la espectroscopia cercana al infrarrojo en la encefalopatía hipóxico-isquémica.

INTRODUCTION: Despite treatment with hypothermia, 40% of newborns with hypoxic-ischaemic encephalopathy die or suffer moderate to severe disability. Near-infrared spectroscopy (NIRS) could be a useful, non-invasive tool to establish the prognosis. OBJECTIVES: To evaluate the prognostic value of NIRS in predicting neurodevelopmental outcomes at 18 to 36 months in newborns with hypoxic-ischaemic encephalopathy, and to establish the time points and cut-off values of regional cerebral oxygen saturation that exhibit the strongest correlation to these outcomes. PATIENTS AND METHODS: The study included all term newborns with hypoxic-ischaemic encephalopathy managed with hypothermia and NIRS between 2013 and 2016. We established 3 outcome categories: normal neurodevelopment, moderate disability and severe disability. RESULTS: The sample comprised 28 newborns (median gestational age, 39 weeks; median birth weight, 3195g). The median regional cerebral oxygen saturation increased from 65% to 85% at 48hours post birth. Neurodevelopmental outcomes were normal in 28.6%, while 35.7% developed moderate disability and 35.7% severe disability; 3 patients died. We found a statistically significant difference between groups at 48hours (P=.005) and after hypothermia (P=.03), with higher values in patients with disability. When we compared patients in the severe disability group with the other groups, we found a statistically significant area under the ROC curve at 48hours of 0.872 (P=.001) applying a regional cerebral oxygen saturation cutoff of 83.5%. After hypothermia, regional cerebral oxygen saturation values below 66.0% (AUC, 0.794; P=.017) predicted normal development, while values above 82% (AUC, 0.881; P=.001) predicted severe disability. CONCLUSIONS: NIRS seems to be a valuable tool to predict neurodevelopmental outcomes in patients with hypoxic-ischaemic encephalopathy, even after hypothermia, with higher cerebral oxygen saturation values in patients with disability.

[Ultrasound Assessment of Ventilator-induced Diaphragmatic Dysfunction in Paediatrics]. / Avaliação Ecográfica da Disfunção Diafragmática Induzida pelo Ventilador em Idade Pediátrica.

INTRODUCTION: Invasive mechanical ventilation contributes to ventilator-induced diaphragmatic dysfunction, delaying extubation and increasing mortality in adults. Despite the possibility of having a higher impact in paediatrics, this dysfunction is not routinely monitored. Diaphragm ultrasound has been proposed as a safe and non-invasive technique for this purpose. The aim of this study was to describe the evolution of diaphragmatic morphology and functional measurements by ultrasound in ventilated children. MATERIAL AND METHODS: Prospective exploratory study. Children admitted to Paediatric Intensive Care Unit requiring mechanical ventilation > 48 hours were included. The diaphragmatic thickness, excursion and the thickening fraction were assessed by ultrasound. RESULTS: Seventeen cases were included, with a median age of 42 months. Ten were male, seven had comorbidities and three in seventeen had malnutrition at admission. The median time under mechanical ventilation was seven days. The median of the initial and minimum diaphragmatic thickness was 2.3 mm and 1.9 mm, respectively, with a median decrease in thickness of 13% under pressure-regulated volume control. Diaphragmatic atrophy was observed in 14/17 cases. Differences in the median thickness variation were found between patients with sepsis and without (0.70 vs 0.25 mm; p = 0.019). During pressure support ventilation there was a tendency to increase diaphragmatic thickness and excursion. Extubation failure occurred for diaphragmatic thickening fraction ≤ 35%. DISCUSSION: Under pressure-regulated volume control there was a tendency for a decrease in diaphragmatic thickness. In the pre-extubation stage under pressure support, there was a tendency for it to increase. These results suggest that, by titrating ventilation using physiological levels of inspiratory effort, we can reduce the diaphragmatic morphological changes associated with ventilation. CONCLUSION: The early recognition of diaphragmatic changes may encourage a targeted approach, namely titration of ventilation, in order to reduce ventilator-induced diaphragmatic dysfunction and its clinical repercussions.

Introdução: A ventilação mecânica invasiva condiciona disfunção diafragmática, atrasando a extubação e aumentando a mortalidade em adultos. Em pediatria, apesar de eventualmente mais relevante, essa disfunção não é sistematicamente avaliada. A ecografia diafragmática tem sido proposta como uma técnica não invasiva e segura para esse fim. O objetivo deste estudo foi descrever a evolução dos índices ecográficos de morfologia e função diafragmáticas em crianças ventiladas. Material e Métodos: Estudo exploratório, prospetivo. Foram incluídas crianças admitidas num Serviço de Cuidados Intensivos Pediátricos sob ventilação mecânica invasiva > 48 horas e realizadas medições ecográficas de espessura, excursão e fração de espessamento diafragmáticas. Resultados: Foram incluídos 17 casos. Mediana de idades: 42 meses. Eram do género masculino 10/17, tinham comorbilidades 7/17 e manifestavam desnutrição na admissão 3/17 casos. Mediana do tempo sob ventilação invasiva: sete dias. Medianas das espessuras diafragmáticas inicial e mínima: 2,3 e 1,9 mm, respetivamente, tendo-se observado uma diminuição mediana da espessura de 13% sob volume controlado regulado por pressão. Observou-se atrofia diafragmática em 14/17 casos. Verificaram-se diferenças na mediana da variação da espessura entre os grupos com e sem sépsis (0,70 vs 0,25 mm; p = 0,019). Durante a ventilação em pressão de suporte, observou-se uma tendência para aumento da espessura e excursão diafragmáticas. Ocorreu falência de extubação parafração de espessamento ≤ 35%. Discussão: Sob volume controlado regulado por pressão verificou-se tendência para diminuição da espessura diafragmática. Sob pressão de suporte, verificou-se uma tendência para o seu aumento. Estes resultados sugerem que, titulando a ventilação, podemos reduzir as alterações morfológicas diafragmáticas associadas à ventilação. Conclusão: O reconhecimento precoce de alterações diafragmáticas poderá fomentar uma abordagem dirigida, de forma a limitar a disfunção diafragmática induzida pelo ventilador e suas repercussões.

Evolution and functional classification of mammalian copper amine oxidases.

Mammalian copper-containing amine oxidases (CAOs), encoded by four genes (AOC1-4) and catalyzing the oxidation of primary amines to aldehydes, regulate many biological processes and are linked to various diseases including inflammatory conditions and histamine intolerance. Despite the known differences in their substrate preferences, CAOs are currently classified based on their preference for either primary monoamines (EC 1.4.3.21) or diamines (EC 1.4.3.22). Here, we present the first extensive phylogenetic study of CAOs that, combined with structural analyses of the CAO active sites, provides in-depth knowledge of their relationships and guidelines for classification of mammalian CAOs into AOC1-4 sub-families. The phylogenetic results show that CAOs can be classified based on two residues, X1 and X2, from the active site motif: T/S-X1-X2-N-Y-D. Residue X2 discriminates among the AOC1 (Tyr), AOC2 (Gly), and AOC3/AOC4 (Leu) proteins, while residue X1 further classifies the AOC3 (Leu) and AOC4 (Met) proteins that so far have been poorly identified and annotated. Residues X1 and X2 conserved within each sub-family and located in the catalytic site seem to be the key determinants for the unique substrate preference of each CAO sub-family. Furthermore, one residue located at 10 Šdistance from the catalytic site is different between the sub-families but highly conserved within each sub-family (Asp in AOC1, His in AOC2, Thr in AOC3 and Asn in AOC4) and likely contributes to substrate selectivity. Altogether, our results will benefit the design of new sub-family specific inhibitors and the design of in vitro tests to detect individual CAO levels for diagnostic purposes.

Diagnosis and treatment of neuroendocrine tumors - A series of 13 clinical cases (2014-2017).

Paragangliomas and pheocromocytomas are rare neuroendocrine tumors with different clinical presentation, being responsible for secondary arterial hypertension with target-organ lesions. Surgery is a curative therapy in these tumors and demands a multidisciplinary approach. These tumors are more frequent between the 4th and 5th decades of life and their clinical manifestations are related to catecholamines production: headache, palpitations, variable blood pressure. This article presents 13 clinical cases of patients with neuroendocrine tumors, with an median-age of 56,7 years, submitted to surgery between 2014 and 2017. The diagnosis was made based on clinical suspicion, serum and urinary catecholamines and metanephrins, imagiologic evaluation with CT or abdominal and pelvic MRI and MIBG scintigraphy. After surgery, the majority of patients remained with normal blood pressure, without anti-hypertensive therapy and follow-up was maintained in Outpatient Clinic, with periodic blood tests and imaging reevaluation.

Fever and Rash: Revisiting Measles.

Fever and rash are a common combination of symptoms in the young adult patient. The etiologic investigation is usually oriented towards the most common diseases, but atypical presentations of less frequent conditions should also be recalled. We describe the case of a 44 year-old Portuguese woman who presented with fever, conjunctivitis, cough and rash, rapidly evolving to hepatitis and extensive pneumonia with respiratory failure. Although she claimed to be vaccinated according to the national immunisation schedule, a final diagnosis of primary measles pneumonia was clinically made and confirmed by serology. However, some less typical features mislead us initially. Although the rare form of primary measles pneumonia is more prevalent among immunosuppressed patients, our patient was immunocompetent. Moreover, absence of contagiousness, as was the case, occurs more frequently in atypical measles. This case highlights the need to always confirm the alleged vaccination status in adults and raises attention to some unusual features of typical measles.

Febre e exantema são uma combinação comum de sintomas no jovem adulto. A investigação etiológica é geralmente direcionada para as doenças mais frequentes, mas apresentações atípicas de condições menos frequentes também devem ser recordadas. Apresentamos o caso clínico de uma mulher portuguesa de 44 anos que apresentou quadro caracterizado por febre, conjuntivite, tosse e exantema, evoluindo rapidamente para hepatite e pneumonia extensa com insuficiência respiratória. Embora afirmasse ter o programa nacional de vacinação actualizado, os achados clínicos e o resultado serológico foram conclusivos de pneumonia primária a sarampo típico. Contudo, algumas manifestações menos típicas tornaram o diagnóstico menos óbvio. Embora a forma rara de pneumonia primária a sarampo seja mais frequente nos doentes imunodeprimidos, a nossa doente era imunocompetente. A ausência de contágio, tal como neste caso, ocorre mais frequente no sarampo atípico. Este caso clínico pretende mostrar a importância da confirmação do estado vacinal nos adultos, sublinhando ainda algumas apresentações atípicas de sarampo típico.

Secondary hypertension due to a juxtaglomerular cell tumor.

Juxtaglomerular cell tumors are rare, generally benign, and they are one of the secondary surgically treatable causes of arterial hypertension. There are about 100 reported cases on literature, and the diagnosis is usually carried out based on a high clinic suspicion index, mostly in patients with hypokalemia and arterial hypertension. The diagnosis involves blood tests and imaging studies, but it is only definite with histopathological exam after surgical treatment. We present a case of a 22-year-old woman with resistant arterial hypertension and renal and cardiovascular target-organ lesions. High plasmatic renin and a nodular renal mass on magnetic resonance imaging were present. A tumorectomy was performed and the histological exam confirmed a reninoma. After surgery, blood pressure and serum renin values returned to normal without medication. This work focuses on the need to exclude rare secondary causes of hypertension in young patients with resistant forms of this disease.

Teenage boy with high fever and rash: what could we be missing?

A 15-year-old boy was admitted to a local hospital with high fever, generalised rash and a mild sore throat. He was started on intravenous flucloxacillin and 12 hours later develops a sustained low diastolic blood pressure (DBP), unresponsive to fluid volume expansion and cardiovascular support with dopamine. Intravenous clindamycin was added and transportation to paediatric intensive care unit arranged. Dopamine dosing was increased and norepinephrine infusion was added subsequently with immediate stabilisation of DBP. A sacrococcygeal pilonidal abscess was identified, requiring prompt surgical drainage. The microbiological culture of abscess material was positive for an enterotoxin-producing Staphylococcus aureus and Peptostreptococcus magnus He was free of symptoms after 4 days. This case report summarises a potential severe complication of the pilonidal disease.

Mapping the interaction site and effect of the Siglec-9 inflammatory biomarker on human primary amine oxidase.

Human primary amine oxidase (hAOC3), also known as vascular adhesion protein 1, mediates leukocyte rolling and trafficking to sites of inflammation by a multistep adhesion cascade. hAOC3 is absent on the endothelium of normal tissues and is kept upregulated during inflammatory conditions, which is an applicable advantage for imaging inflammatory diseases. Sialic acid binding immunoglobulin like-lectin 9 (Siglec-9) is a leukocyte ligand for hAOC3. The peptide (CARLSLSWRGLTLCPSK) based on the region of Siglec-9 that interacts with hAOC3, can be used as a specific tracer for hAOC3-targeted imaging of inflammation using Positron Emission Tomography (PET). In the present study, we show that the Siglec-9 peptide binds to hAOC3 and triggers its amine oxidase activity towards benzylamine. Furthermore, the hAOC3 inhibitors semicarbazide and imidazole reduce the binding of wild type and Arg/Ala mutated Siglec-9 peptides to hAOC3. Molecular docking of the Siglec-9 peptide is in accordance with the experimental results and predicts that the R3 residue in the peptide interacts in the catalytic site of hAOC3 when the topaquinone cofactor is in the non-catalytic on-copper conformation. The predicted binding mode of Siglec-9 peptide to hAOC3 is supported by the PET studies using rodent, rabbit and pig AOC3 proteins.

Oligomannosidic glycans at Asn-110 are essential for secretion of human diamine oxidase.

N-Glycosylation plays a fundamental role in many biological processes. Human diamine oxidase (hDAO), required for histamine catabolism, has multiple N-glycosylation sites, but their roles, for example in DAO secretion, are unclear. We recently reported that the N-glycosylation sites Asn-168, Asn-538, and Asn-745 in recombinant hDAO (rhDAO) carry complex-type glycans, whereas Asn-110 carries only mammalian-atypical oligomannosidic glycans. Here, we show that Asn-110 in native hDAO from amniotic fluid and Caco-2 cells, DAO from porcine kidneys, and rhDAO produced in two different HEK293 cell lines is also consistently occupied by oligomannosidic glycans. Glycans at Asn-168 were predominantly sialylated with bi- to tetra-antennary branches, and Asn-538 and Asn-745 had similar complex-type glycans with some tissue- and cell line-specific variations. The related copper-containing amine oxidase human vascular adhesion protein-1 also exclusively displayed high-mannose glycosylation at Asn-137. X-ray structures revealed that the residues adjacent to Asn-110 and Asn-137 form a highly conserved hydrophobic cleft interacting with the core trisaccharide. Asn-110 replacement with Gln completely abrogated rhDAO secretion and caused retention in the endoplasmic reticulum. Mutations of Asn-168, Asn-538, and Asn-745 reduced rhDAO secretion by 13, 71, and 32%, respectively. Asn-538/745 double and Asn-168/538/745 triple substitutions reduced rhDAO secretion by 85 and 94%. Because of their locations in the DAO structure, Asn-538 and Asn-745 glycosylations might be important for efficient DAO dimer formation. These functional results are reflected in the high evolutionary conservation of all four glycosylation sites. Human DAO is abundant only in the gastrointestinal tract, kidney, and placenta, and glycosylation seems essential for reaching high enzyme expression levels in these tissues.

Biochemical characterization and homology modeling of polyamine oxidase from cyanobacterium Synechocystis sp. PCC 6803.

The intracellular polyamine contents are regulated not only by polyamine biosynthesis and transport but also by polyamine degradation catalyzed by copper-dependent amine oxidase (DAO) and FAD-dependent polyamine oxidase (PAO). The genome sequence of Synechocystis sp. PCC 6803 reveals the presence of at least one putative polyamine oxidase gene, slr5093. The open reading frame of slr5093 encoding Synechocystis polyamine oxidase (SynPAO, E.C. 1.5.3.17) was expressed in Escherichia coli. The purified recombinant enzyme had the characteristic absorption spectrum of a flavoprotein with absorbance peaks at 380 and 450 nm. The optimum pH and temperature for the oxidation of both spermidine and spermine are 8.5 and 30 °C, respectively. The enzyme catalyzed the conversion of spermine and spermidine to spermidine and putrescine, respectively, with higher catalytic efficiency when spermine served as substrate. These results suggest that SynPAO is a polyamine oxidase involved in a polyamine back-conversion pathway. Based on the structural analysis, Gln94, Tyr403 and Thr440 in SynPAO are predicted to be important residues in the active site.

Slr0006-like proteins: A TsaC/TsaC2/YciO subfamily exclusive to cyanobacteria.

The universally conserved TsaC/TsaC2/YciO family of proteins is essential for the N6-threonylcarbamoyladenosine modification present in almost all ANN-decoding tRNAs. Previously, the family has been grouped into the TsaC/TsaC2 and YciO subfamilies. We used sequence analysis, phylogenetic methods and homology modeling to show that a third subfamily, the Slr0006-like subfamily, exists exclusively in some cyanobacteria. The Slr0006-like proteins are solely found together with both TsaC and YciO homologs, indicating a distinct function for the Slr0006-like subfamily. Accordingly, the homology models show that the amino acids in their putative binding clefts differ significantly. Hence, we introduce a new cyanobacterial subfamily of proteins with the TsaC-domain fold, along with the generated classification rules to assign new members to the correct cyanobacterial subfamily.

A New Anaesthetic Protocol for Adult Zebrafish (Danio rerio): Propofol Combined with Lidocaine.

BACKGROUND: The increasing use of zebrafish model has not been accompanied by the evolution of proper anaesthesia for this species in research. The most used anaesthetic in fishes, MS222, may induce aversion, reduction of heart rate, and consequently high mortality, especially during long exposures. Therefore, we aim to explore new anaesthetic protocols to be used in zebrafish by studying the quality of anaesthesia and recovery induced by different concentrations of propofol alone and in combination with different concentrations of lidocaine. MATERIAL AND METHODS: In experiment A, eighty-three AB zebrafish were randomly assigned to 7 different groups: control, 2.5 (2.5P), 5 (5P) or 7.5 µg/ml (7.5P) of propofol; and 2.5 µg/ml of propofol combined with 50, (P/50L), 100 (P/100L) or 150 µg/ml (P/150L) of lidocaine. Zebrafish were placed in an anaesthetic water bath and time to lose the equilibrium, reflex to touch, reflex to a tail pinch, and respiratory rate were measured. Time to gain equilibrium was also assessed in a clean tank. Five and 24 hours after anaesthesia recovery, zebrafish were evaluated concerning activity and reactivity. Afterwards, in a second phase of experiments (experiment B), the best protocol of the experiment A was compared with a new group of 8 fishes treated with 100 mg/L of MS222 (100M). RESULTS: In experiment A, only different concentrations of propofol/lidocaine combination induced full anaesthesia in all animals. Thus only these groups were compared with a standard dose of MS222 in experiment B. Propofol/lidocaine induced a quicker loss of equilibrium, and loss of response to light and painful stimuli compared with MS222. However zebrafish treated with MS222 recovered quickly than the ones treated with propofol/lidocaine. CONCLUSION: In conclusion, propofol/lidocaine combination and MS222 have advantages in different situations. MS222 is ideal for minor procedures when a quick recovery is important, while propofol/lidocaine is best to induce a quick and complete anaesthesia.

[The Importance of Early Referral in Pediatric Acute Liver Failure]. / A Importância da Referenciação Precoce na Falência Hepática Aguda Pediátrica.

INTRODUCTION: Acute liver failure is a rare disorder associated to high morbidity and mortality despite survival improvement through liver transplantation. The importance of a multidisciplinary approach and early referral to a pediatric liver transplantation center were important conclusions of a national meeting in 2008, from which resulted an actuation consensus. OBJECTIVES: To characterize acute liver failure admissions in a Pediatric Intensive Care Unit of the portuguese pediatric livertransplantation center. To compare results before (A) and after (B) 2008. MATERIAL AND METHODS: Observational, retrospective study during a 20 year period (1994-2014). INCLUSION CRITERIA: age < 18 years old and acute liver failure (INR ≥ 2 without vitamin K response and hepatocellular necrosis). Children with previous liver disease were excluded. RESULTS: Fifty children were included, with median age of 24.5 months. The most common etiology under 2 years old was metabolic (34.6%) and above that age was infectious (29.2%). Forty six percent were submitted to liver transplantation and 78% of them survived. Overall mortality was 34%. Median referral time was 7 days in period A (n = 35) and 2 days in period B (n = 15; p = 0.006). Pediatric risk of mortality's median was 14.7 in period A and 6.5 in B (p = 0.019). Mortality was 37% vs 26% in periods A and B, respectively (p = 0.474). DISCUSSION AND CONCLUSIONS: Overall mortality was similar to the observed in other European centers. Liver transplantation is in fact the most effective therapeutic option. After 2008, there was a reduction in referral time and cases severity on admission; however, mortality has not reduced so far.

Introdução: A falência hepática aguda é uma doença rara associada a elevada morbilidade e mortalidade apesar do aumento da sobrevida devido ao transplante hepático. Em 2008, decorreu em Portugal uma reunião sobre esta patologia em pediatria, resultando num consenso de atuação que salientou a importância da abordagem multidisciplinar e referenciação precoce para um centro de transplantação hepática. Objetivos: Caracterizar as admissões por falência hepática aguda no Serviço de Cuidados Intensivos Pediátricos do centro português com transplante hepático pediátrico. Comparar resultados antes (A) e depois de 2008 (B). Material e Métodos: Estudo observacional retrospetivo de 20 anos (1994-2014). Critérios de inclusão: idade < 18 anos e falência hepática aguda (INR ≥ 2 sem resposta à vitamina K e necrose hepatocelular). Excluíram-se as crianças com doença hepática crónica. Resultados: Incluíram-se 50 crianças com idade mediana de 24,5 meses. A causa mais comum de falência hepática aguda abaixo dos 2 anos foi metabólica (34,6%) e acima infeciosa (29,2%). Foram submetidos a transplante hepático 46%, tendo sobrevivido 78%. A mortalidade global foi 34%. A mediana do tempo de referenciação foi 7 dias no período A (n = 35) e 2 no B (n = 15; p = 0,006). A mediana do risco de mortalidade prevista pelo PRISM foi 14,7% no período A e 6,5% no B (p = 0,019). A mortalidade foi 37% vs 26% no período A e B respetivamente (p = 0,474).Discussão e Conclusões: A mortalidade global foi sobreponível à de outros centros europeus, sendo o transplante hepático a opção terapêutica mais eficaz. Após 2008 o tempo de referenciação e a gravidade dos casos na admissão reduziram, ainda sem tradução significativa na mortalidade.

Invasive Meningococcal Disease: Application of Base Excess and Platelets Score in a Portuguese Paediatric Intensive Care Unit.

INTRODUCTION: Meningococcal infection has a high mortality and morbidity. Recently a new prognostic scoring system was developed for paediatric invasive meningococcal disease, based on platelet count and base excess â base excess and platelets score. The main objective of this study was to evaluate the accuracy of base excess and platelets score to predict mortality in children admitted to intensive care due to invasive meningococcal disease. MATERIAL AND METHODS: Observational study, with retrospective data collection, during a 13.5 years period (01/2000 to 06/2013). Mortality by invasive meningococcal disease and related factors (organ dysfunction and multi-organ failure) were analysed. The base excess and platelets score was calculated retrospectively, to evaluate its accuracy in predicting mortality and compared with Paediatric Risk of Mortality and Paediatric Index of Mortality2. RESULTS: Were admitted 76 children with invasive meningococcal disease. The most frequent type of dysfunction was cardiovascular (92%), followed by hematologic (55%). Of the total, 47 patients (62%) had criteria for multi-organ failure. The global mortality was 16%. Neurologic and renal dysfunction showed the strongest association with mortality, adjusted odds ratio 315 (26 - 3 804) and 155 (20 - 1 299). After application of receiver operating characteristic curves, Base Excess and Platelets score had an area under curve of 0.81, Paediatric Index of Mortality2 of 0.91 and Paediatric Risk of Mortality of 0.96. DISCUSSION: The Base Excess and Platelets score showed good accuracy, although not as high as Paediatric Risk of Mortality or Paediatric Index of Mortality2. CONCLUSIONS: The Base Excess and Platelets score may be useful tool in invasive meningococcal disease because is highly sensitive and specific and is objectively measurable and readily available at presentation.

Introdução: A infeção meningocócica tem uma elevada mortalidade e morbilidade. Recentemente foi desenvolvido um score de prognóstico para a doença meningocócica invasiva em idade pediátrica, baseado na contagem plaquetar e no excesso de base - o Base Excess and Platelets Score. O objetivo principal desde estudo foi avaliar a precisão prognóstica do Base Excess and Platelets Score em doentes admitidos em cuidados intensivos pediátricos por doença meningocócica invasiva.Material e Métodos: Estudo observacional, com colheita de dados retrospetiva, que incluiu um período de 13,5 anos (01/2000 a 06/2013). Foram analisados: mortalidade por doença meningocócica invasiva e fatores associados (disfunção de órgão e falência multi-órgão). Foi calculado o Base Excess and Platelets Score de forma retrospetiva, para avaliar a sua precisão na predição da mortalidade e foi comparado com o Paediatric Risk of Mortality e Paediatric Index of Mortality2.Resultados: Foram admitidas 76 crianças com doença meningocócica invasiva. O tipo de disfunção mais frequente foi a cardiovascular (92%), seguida da hematológica (55%). Cumpriram critérios de falência multi-órgão 47 doentes (62%). A mortalidade global foi de 16%. A disfunção neurológica e a renal foram as que apresentaram uma maior associação com a mortalidade, odds ratio ajustado 315 (26 - 3 804) e 155 (20 - 1 299). Após aplicação das curvas receiver operating characteristic, o Base Excess and Platelets Score tinha umaarea under curve de 0,81, o Paediatric Index of Mortality2 de 0,91 e o Paediatric Risk of Mortality de 0,96.Discussão: O Base Excess and Platelets Score apresentou uma boa precisão apesar de não tão elevada como o Paediatric Index of Mortality2 ou o Paediatric Risk of Mortality.Conclusões: O Base Excess and Platelets Score pode ser útil como indicador prognóstico na doença meningocócica invasiva, por apresentar uma elevada sensibilidade e especificidade e ser objetivo e rapidamente disponível na admissão.