Arnout Jan de Beaufort

Effect of interleukin 8 in meconium on in-vitro neutrophil chemotaxis

BACKGROUND Pneumonitis, characterised by large numbers of neutrophils in the lung, is an important feature of the meconium aspiration syndrome. The mechanism underlying the neutrophil influx is not known. We have investigated whether meconium has chemotactic activity and whether such activity is related to the presence of interleukin 8. METHODS The chemotactic activity of meconium on neutrophils from newborn infants was assessed in a Boyden-chamber assay. Interleukin 8 and formyl-methionyl-leucyl-phenylalanine (f-MLP) served as positive controls. Inhibition of chemotaxis was assessed with monoclonal antibody to interleukin 8. The interleukin-8 concentration was measured by ELISA. FINDINGS Sterile meconium suspension from seven unrelated newborn babies increased migration of neutrophils from neonates in comparison with random migration (79, 72, 70, 50, 58, 88 microm vs 46 microm; p<0.001). This effect was greatest at a meconium concentration of 5 g/L, although differences between samples from individual babies were observed. Interleukin 8 was present in all meconium suspensions (480-3980 ng/L). Anti-interleukin-8 inhibited neutrophil migration. INTERPRETATION Interleukin 8 is present in meconium and it induces chemotaxis of neutrophils in vitro. This mechanism may have a role in the pathogenesis of pneumonitis in meconium aspiration syndrome.

Meconium Is a Source of Pro-Inflammatory Substances and Can Induce Cytokine Production in Cultured A549 Epithelial Cells

Inflammation plays an important role in the pathogenesis of meconium aspiration syndrome, and pneumonitis is one of the major characteristics. We have previously shown that meconium has chemotactic properties because of the presence of IL-8. We hypothesize that IL-8 and other proinflammatory substances in meconium may amplify inflammation in meconium aspiration syndrome, inducing endogenous cytokine production by lung epithelial cells. We measured proinflammatory substances in first-pass meconium from healthy newborns and evaluated the effect of sterile meconium on cytokine production in cultured A549 alveolar epithelial cells in vitro. IL-1β, IL-6, IL-8, and tumor necrosis factor-α were measured by ELISA, and heme was measured spectrophotometrically. After incubation of meconium samples with A549 cells, cytokine concentrations in the supernatant were measured. Meconium samples contained variable amounts of IL-1β, IL-6, IL-8, tumor necrosis factor-α, and heme. On stimulation of A549 cells with meconium, the IL-8 concentration in the culture supernatant significantly increased above baseline measurements, whereas tumor necrosis factor-α showed a variable pattern and IL-1β or IL-6 remained unchanged. There was no quantitative relationship between the concentration of the measured cytokines and heme in meconium and cytokine release by the A549 cells after meconium exposure. Meconium contains proinflammatory substances. All samples induced IL-8 release and some induced tumor necrosis factor-α release in cultured A549 epithelial cells. We speculate that proinflammatory substances in meconium can induce lung inflammation in meconium aspiration syndrome in two ways: directly via cytokines and heme present in meconium and indirectly by inducing cytokine release by the epithelial lung cells.

Transepidermal Water Loss During Halogen Spotlight Phototherapy in Preterm Infants

Among preterm infants there is a relationship between skin blood flow and transepidermal water loss (TEWL). The aim of this study was to assess whether halogen spotlight phototherapy without significant heat stress increases TEWL and affects maintenance fluid requirements in preterm infants. TEWL was measured noninvasively before the start and after 1 h of halogen spotlight phototherapy in a group of preterm infants, nursed in double-walled incubators with moderately high relative humidity. Relative humidity and ambient temperature in the incubator were tightly controlled. Mean ± SD birth weight of the 18 infants was 1412 ± 256 g, gestational age 30.6 ± 1.6 wk, and age at measurement 5 ± 3 d. Nine infants received ventilatory assistance. Relative humidity was 40–80% (mean 52%). Average TEWL increased from 13.6 to 16.5 g/m2/h during phototherapy. These data show that TEWL increases by approximately 20% during phototherapy despite constant skin temperature and relative humidity. Maintenance fluids of preterm infants should be increased by 0.35 mL/kg/h during exposure to halogen spotlight phototherapy.

Fostering first-year student learning through research integration into teaching: Student perceptions, beliefs about the value of research and student achievement

ABSTRACT Research should be explicated in undergraduate teaching in a way that stimulates student learning. Previous studies in higher education have shown that student perceptions of research integrated into teaching could promote student learning, but have also indicated that it can be difficult to confront first-year undergraduates with research during courses. In this study, we describe relationships between first-year medical student perceptions of research, learning outcomes and beliefs about the value of research. The Student Perception of Research Integration Questionnaire was filled out by 261 students. Answers were related to student achievement. The findings suggest that student motivation for research is strongly related to merging current research into teaching. Students rather recognised an emphasis on research methodologies than research engagement. Particularly student beliefs about research are related to achievement. It is suggested that to foster positive beliefs about research, teachers should familiarise students with current research and create enthusiasm for research.

Causes and characteristics of medical student referrals to a professional behaviour board.

Objectives To describe the nature of unprofessional behaviour displayed by medical students, as well as the characteristics of students referred to the professional behaviour board. Methods A descriptive mixed methods approach was taken, in which qualitative data on unprofessional behaviour, as well as quantitative data on the demographics of referred students were collected during the study period between June 1, 2009 and January 1, 2014. In order to compare the referred students with the total student population, data on gender, nationality and phase in the curriculum of the total student population, collected from the student administration desk, were also used. Results In the study period, a total of 107 referrals were reported, concerning 93 different students (3% of the total student population). Sixty-five of the 107 referrals (61%) concerned male students. Thirty referrals (28%) concerned non-Dutch students. Most referrals (71%) occurred during clinical rotations. The referrals were equally distributed over three professional behaviour domains: dealing with oneself, dealing with others, and dealing with tasks/work. ‘Withdrawn behaviour’ was reported 17 times, ‘insufficient Dutch language proficiency’ 14 times, ‘impertinent emails’ 9 times and ‘placing privacy-sensitive photos on the internet’ 3 times. Conclusions Although only a minority of students are referred to a professional behaviour board, this study shows that student characteristics such as gender and nationality may correlate to a higher incidence of unprofessional behaviour. Further explanatory and exploratory research is needed to unravel this relationship, and to study the influence of curriculum reforms on these relationships, respectively.

Pulmonary Secretory Phospholipase A2 in Infants with Respiratory Distress Syndrome Stimulates in vitro Neutrophil Migration

Background: The massive pulmonary neutrophil influx in respiratory distress syndrome (RDS) in preterm infants has been ascribed to the effect of leukotriene B₄ (LTB₄). Objectives: To investigate whether secretory phospholipase A₂ (sPLA₂), the rate-limiting enzyme in LTB₄ production, is present in lungs of RDS infants and stimulates neutrophil migration. Methods: sPLA₂ was measured in tracheal aspirates from 15 preterm infants with RDS. The effect of aspirates on cord blood neutrophil migration was first measured, and the contribution of sPLA₂ was assessed by addition of its endogenous inhibitor Clara cell protein (CC16) or absorption of sPLA₂ from the aspirates. The role of intracellular signal transduction activation and LTB₄ formation in sPLA₂-induced neutrophil migration was determined using purified sPLA₂, several inhibitors of signal transduction, a LTB₄ synthesis inhibitor and a LTB₄ receptor antagonist. Results: All aspirates contained sPLA₂, which significantly stimulated neutrophil migration. Addition of CC16 or absorption of sPLA₂ abolished the stimulatory effect. All inhibitors significantly reduced sPLA₂-induced neutrophil migration. Conclusions: sPLA₂ is present in tracheal aspirates of preterm infants with RDS. Human recombinant sPLA₂ and pancreatic type sPLA₂ stimulate in vitro cord blood neutrophil migration via activation of intracellular signal transduction pathways, LTB₄ production and receptor binding. We speculate that sPLA₂ contributes to pulmonary neutrophil influx in RDS. Further studies are needed to determine the potential of sPLA₂ inhibition as a treatment for RDS.

Effect of plasma transfusions on iron induced oxygen damage in newborns: an in vitro study. † 827

Reperfusion after shock can trigger iron induced oxidative damage and therefore the influence of infusion fluids on the iron binding capacity of plasma may be important. Therefore in vitro the effects of adding fresh frozen plasma (FFP), pasteurized plasma protein solution (PPPS) and saline (NaCl), in volumes equivalent to 20 ml/kg infusions, to the plasma of 10 preterm and 10 term babies (g.a. 33.7±2.6 and 39.6±1.1 wks resp.) and 10 adults (age 32±10 y) were compared by measuring the transferrin iron binding antioxidant capacity (% inhibition of lipid peroxidation,%INH) and the level of non-protein-bound iron (NPBI, bleomycin method) in plasma.

Encouraging residents’ professional development and career planning: the role of a development-oriented performance assessment

BackgroundCurrent postgraduate medical training programmes fall short regarding residents’ development of generic competencies (communication, collaboration, leadership, professionalism) and reflective and deliberate practice. Paying attention to these non-technical skills in a structural manner during postgraduate training could result in a workforce better prepared for practice. A development-oriented performance assessment (PA), which assists residents with assessment of performance and deliberately planned learning activities, could potentially contribute to filling this gap. This study aims to explore residents experiences with the PA.MethodsWe conducted a qualitative interview study with 16 residents from four different medical specialties who participated in the PA, scheduled halfway postgraduate training. The PA was conducted by an external facilitator, a psychologist, and focused specifically on professional development and career planning. Residents were interviewed 6 months after the PA. Data were analysed using the framework method for qualitative analysis.ResultsResidents found the PA to be of additional value for their training. The overarching merit was the opportunity to evaluate competencies not usually addressed in workplace-based assessments and progress conversations. In addition, the PA proved a valuable tool for assisting residents with reflecting upon their work and formulating their learning objectives and activities. Residents reported increased awareness of capacity, self-confidence and enhanced feelings of career-ownership. An important factor contributing to these outcomes was the relationship of trust with the facilitator and programme director.ConclusionThe PA is a promising tool in fostering the development of generic competencies and reflective and deliberate practice. The participating residents, facilitator and programme directors were able to contribute to a safe learning environment away from the busy workplace. The facilitator plays an important role by providing credible and informative feedback. Commitment of the programme director is important for the implementation of developmental plans and learning activities.

133 INHALATION OF NITRIC OXIDE: EFFECT ON HEMODYNAMICS, CEREBRAL ACTIVITY AND ANTIOXIDANT STATUS IN THE LAMB

Ventilation with NO is increasingly being used to treat pulmonary hypertension in the newborn. In the brain NO is involved in neurotransmission and has vasoactive properties. However, the effect of inhaled NO on cerebral function and blood flow is not known. Furthermore, there is little information on the peroxidative complications by use of this free radical gas.We investigated the effect of inhaled NO (1-60 ppm) in 6 ventilated newborn lambs before and after group B streptococci (GBS) induced pulmonary hypertension. Blood pressure in the pulmonary artery (Pap) and aorta (PAo), cerebral blood flow (CBF, ultrasonic-determined carotid flow) and cerebral electrical activity (CEA using a cerebral function monitor) were measured. Blood gases, indices of antioxidant status (vitamin C, MDA and glutathione) and methemoglobin were determined in blood samples from the left ventricle. With inhalation of NO before and after GBS induced pulmonary hypertension a decrease of the Pap (16→11 mmHg and 27→12 mmHg resp) and an increase of the paO2 (13→18 kPa and 10→17 kPa resp) was observed. CBF (65-80 mL/min), CEA (25-45 muV) and indices of antioxidant status were in the normal range and did not change significantly. Methemoglobin was not detected.Inhalation of NO (up to 60 ppm) lowered Pap, without having an effect on CBF, CEA, and antioxidant status in the pulmonary vessels.