RESUMO
OBJECTIVE: To evaluate neurodevelopment after necrotizing enterocolitis (NEC) and late bacteremia, alone and together. STUDY DESIGN: Sample included 1155 infants born at 23 to 27 weeks' gestation. NEC was classified by the modified Bell's staging criteria and grouped as medical NEC or surgical NEC. Late bacteremia was defined as a positive blood culture result after the first postnatal week. Neurodevelopment was assessed at 24 months corrected age. Multivariable models estimated the risk of developmental dysfunction and microcephaly associated with medical or surgical NEC with and without late bacteremia. RESULTS: Children who had surgical NEC unaccompanied by late bacteremia were at increased risk of psychomotor developmental indexes <70 (OR = 2.7 [1.2, 6.4]), and children who had both surgical NEC and late bacteremia were at increased risk of diparetic cerebral palsy (OR = 8.4 [1.9, 39]) and microcephaly (OR = 9.3 [2.2, 40]). In contrast, children who had medical NEC with or without late bacteremia were not at increased risk of any developmental dysfunction. CONCLUSION: The risk of neurodevelopmental dysfunction and microcephaly is increased in children who had surgical NEC, especially if they also had late bacteremia. These observations support the hypothesis that bowel injury might initiate systemic inflammation potentially affecting the developing brain.
Assuntos
Bacteriemia/complicações , Deficiências do Desenvolvimento/etiologia , Enterocolite Necrosante/complicações , Doenças do Prematuro , Doenças do Sistema Nervoso/etiologia , Deficiências do Desenvolvimento/epidemiologia , Idade Gestacional , Humanos , Recém-Nascido , Doenças do Sistema Nervoso/epidemiologia , Estudos Prospectivos , Fatores de RiscoRESUMO
BACKGROUND: Ticks secrete a cement cone composed of many salivary proteins, some of which are rich in the amino acid glycine in order to attach to their hosts' skin. Glycine-rich proteins (GRPs) are a large family of heterogeneous proteins that have different functions and features; noteworthy are their adhesive and tensile characteristics. These properties may be essential for successful attachment of the metastriate ticks to the host and the prolonged feeding necessary for engorgement. In this work, we analyzed Expressed Sequence Tags (ESTs) similar to GRPs from cDNA libraries constructed from salivary glands of adult female ticks representing three hard, metastriate species in order to verify if their expression correlated with biological differences such as the numbers of hosts ticks feed on during their parasitic life cycle, whether one (monoxenous parasite) or two or more (heteroxenous parasite), and the anatomy of their mouthparts, whether short (Brevirostrata) or long (Longirostrata). These ticks were the monoxenous Brevirostrata tick, Rhipicephalus (Boophilus) microplus, a heteroxenous Brevirostrata tick, Rhipicephalus sanguineus, and a heteroxenous Longirostrata tick, Amblyomma cajennense. To further investigate this relationship, we conducted phylogenetic analyses using sequences of GRPs from these ticks as well as from other species of Brevirostrata and Longirostrata ticks. RESULTS: cDNA libraries from salivary glands of the monoxenous tick, R. microplus, contained more contigs of glycine-rich proteins than the two representatives of heteroxenous ticks, R. sanguineus and A. cajennense (33 versus, respectively, 16 and 11). Transcripts of ESTs encoding GRPs were significantly more numerous in the salivary glands of the two Brevirostrata species when compared to the number of transcripts in the Longirostrata tick. The salivary gland libraries from Brevirostrata ticks contained numerous contigs significantly similar to silks of true spiders (17 and 8 in, respectively, R. microplus and R. sanguineus), whereas the Longirostrata tick contained only 4 contigs. The phylogenetic analyses of GRPs from various species of ticks showed that distinct clades encoding proteins with different biochemical properties are represented among species according to their biology. CONCLUSIONS: We found that different species of ticks rely on different types and amounts of GRPs in order to attach and feed on their hosts. Metastriate ticks with short mouthparts express more transcripts of GRPs than a tick with long mouthparts and the tick that feeds on a single host during its life cycle contain a greater variety of these proteins than ticks that feed on several hosts.