Distinct roles of the RasGAP family proteins in C. elegans associative learning and memory

The Ras GTPase activating proteins (RasGAPs) are regulators of the conserved Ras/MAPK pathway. Various roles of some of the RasGAPs in learning and memory have been reported in different model systems, yet, there is no comprehensive study to characterize all gap genes in any organism. Here, using reverse genetics and neurobehavioural tests, we studied the role of all known genes of the rasgap family in C. elegans in associative learning and memory. We demonstrated that their proteins are implicated in different parts of the learning and memory processes. We show that gap-1 contribute redundantly with gap-3 to the chemosensation of volatile compounds, gap-1 plays a major role in associative learning, while gap-2 and gap-3 are predominantly required for short- and long-term associative memory. Our results also suggest that the C. elegans Ras orthologue let-60 is involved in multiple processes during learning and memory. Thus, we show that the different classes of RasGAP proteins are all involved in cognitive function and their complex interplay ensures the proper formation and storage of novel information in C. elegans

Risk factors for acute respiratory tract infections in general practitioner patients in The Netherlands: a case-control study

<p>Abstract</p> <p>Background</p> <p>Acute respiratory tract infections (ARTI) are an important public health problem. Improved identification of risk factors might enable targeted intervention. Therefore we carried out a case-control study with the aim of identifying environmental risk factors for ARTI consultations in the Dutch general population.</p> <p>Methods</p> <p>A subset of patients visiting their GP in the period of 2000–2003 with an ARTI (cases) and age-matched controls (visiting for other complaints) were included in a case-control study. They were asked to complete a questionnaire about potential risk factors. Conditional logistic regression was used to calculate odds ratio's (OR) and 95% confidence intervals (CI) to estimate the independent effect of potential risk factors.</p> <p>Results</p> <p>A total of 493 matched pairs of case and control subjects were enrolled. Exposure to persons with respiratory complaints, both inside and outside the household, was found to be an independent risk factor for visiting a GP with an ARTI (respectively OR_adj= 1.9 and OR_adj= 3.7). Participants exposed to dampness or mould at home (OR_adj=0.5) were significantly less likely to visit their GP. In accordance with the general risk of consultations for ARTI, participants with a laboratory-confirmed ARTI who were exposed to persons with respiratory complaints outside the household were also significantly more likely to visit their GP (OR_adj=2.5).</p> <p>Conclusion</p> <p>This study confirmed that heterogeneity in the general population as well as in pathogens causing ARTI makes it complicated to detect associations between potential risk factors and respiratory infections. Whereas it may be difficult to intervene on the risk posed by exposure to persons with respiratory complaints, transmission of ARTI in the general population might be reduced by improved hygienic conditions.</p

Impaired cognitive performance in premature newborns with two or more surgeries prior to term-equivalent age.

Anesthesia in early childhood is associated with adverse neurodevelopmental outcome; however, it is not known if age at exposure affects the risk of adverse outcome. Our objective was to evaluate the association of the number and timing of anesthetic exposures for surgery with cognitive outcome in a cohort of premature newborns.A cohort study of exposure to anesthesia for surgery in premature newborns (&lt;33 wk gestation) prospectively evaluated with neonatal magnetic resonance imaging (MRI) and neurodevelopmental testing at 3-6 y was employed. Exposure to anesthesia for surgery was classified as before term-equivalent age (TEA, &lt;42 wk postmenstrual age) or after (≥42 wk). Multivariate regression was performed to analyze the association of composite IQ scores with the number of surgeries before and after TEA.Among 137 newborns, 25 (18.2%) had one surgery before TEA and 18 (13.1%) had ≥2 surgeries. Two or more surgeries before TEA were associated with significantly reduced composite IQ scores at 4.6 ± 0.6 y after adjusting for gestational age and illness severity. Neither the number of surgeries after TEA nor sedation for MRI was associated with cognitive outcome.More than one surgery prior to TEA is independently associated with impaired cognitive performance in premature newborns

Maternal or neonatal infection: association with neonatal encephalopathy outcomes

BACKGROUND: Perinatal infection may potentiate brain injury among children born preterm. The objective of this study was to examine whether maternal and/or neonatal infection are associated with adverse outcomes among term neonates with encephalopathy. METHODS: Cohort study of 258 term newborns with encephalopathy whose clinical records were examined for signs of maternal infection (chorioamnionitis) and infant infection (sepsis). Multivariate regression was used to assess associations between infection, pattern and severity of injury on neonatal MRI, as well as neurodevelopment at 30 months (neuromotor exam, or Bayley Scales of Infant Development II MDI <70 or Bayley III cognitive score <85). RESULTS: Chorioamnionitis was associated with lower risk of moderate-severe brain injury (adjusted OR 0.3; 95% CI 0.1–0.7, P=0.004), and adverse cognitive outcome in children when compared to no chorioamnionitis. Children with signs of neonatal sepsis were more likely to exhibit watershed predominant injury than those without (P=0.007). CONCLUSIONS: Among neonates with encephalopathy, chorioamnionitis was associated with a lower risk of brain injury and adverse outcomes, whereas signs of neonatal sepsis carried an elevated risk. The etiology of encephalopathy and timing of infection and its associated inflammatory response may influence whether infection potentiates or mitigates injury in term newborns