Obiectives To provide suitable animal model (hyperoxia-induced premature rat lung damage) for research of bronchopulmonary dysplasia (BPD) and to better understand pathogenesis of BPD and look for effective drugs to prevent and treat BPD.Methods Rat litters delivered prematurely at 21-day gestation by hysterotomy. Vigorous resuscitation at birth resulted in a high survival rate. Surfactant and antioxidant enzyme (AOE) system were measured. The model was tested in an experiment of hyperoxia-induced lung injury. Results Compared to litters delivered spontaneously at term (gestation 22 days), these preterm rats had immature pulmonary surfactant composition with low total phospholipid (□±s: 10.09±1.49 μg/mg wet weight vs 12.04±1.31 μg/mg wet weight; P=0.0367) and phostidylcholine (5.06±1.82 μg/mg wet weight vs 8.28±2.35 μg/mg wet weight; P=0.0238) levels. The concentrations of AOE enzymes, superoxide dismutase (11.40±2.04 μ/mg DNA vs 15.78±1.84 μ/mg DNA; P<0.01) and catalase (92.81±62.25 μ/mg DNA vs 412.24±117.50 μ/mg DNA; P<0.01) were also significantly lower. Animals exposed to hyperoxia had a significantly higher mortality. Pulmonary edema and histological features of lung damage were observed in the pups exposed to hyperoxia. Conclusions The premature rat model is relatively cheap, readily available and has a high survival rate. Pulmonary surfactant and AOE systems are immature. These properties make them a suitable model for the study of acute and chronic lung damage related to prematurity and O2 toxicity.

INTRODUCTION: In patients with end-stage kidney disease (ESKD) suitable for peritoneal dialysis (PD), PD should ideally be planned and initiated electively (planned-start PD). If patients present late, some centres initiate PD immediately with an urgent-start PD strategy. However, as urgent-start PD is resource intensive, we evaluated another strategy where patients first undergo emergent haemodialysis (HD), followed by early PD catheter insertion, and switch to PD 48-72 hours after PD catheter insertion (early-start PD). Conventionally, late-presenting patients are often started on HD, followed by deferred PD catheter insertion before switching to PD≥14 days after catheter insertion (deferred start PD). METHODS: This is a retrospective study of new ESKD patients, comparing the planned-start, early-start and deferred-start PD strategies. Outcomes within 1 year of dialysis initiation were studied. RESULTS: Of 148 patients, 57 (38.5%) patients had planned-start, 23 (15.5%) early-start and 68 (45.9%) deferred-start PD. Baseline biochemical parameters were similar except for a lower serum urea with planned-start PD. No significant differences were seen in the primary outcomes of technique and patient survival across all 3 subgroups. Compared to planned-start PD, early-start PD had a shorter time to catheter migration (hazard ratio [HR] 14.13, 95% confidence interval [CI] 1.65-121.04, P=0.016) while deferred-start PD has a shorter time to first peritonitis (HR 2.49, 95% CI 1.03-6.01, P=0.043) and first hospital admission (HR 2.03, 95% CI 1.35-3.07, P=0.001). CONCLUSION Planned-start PD is the best PD initiation strategy. However, if this is not possible, early-start PD is a viable alternative. Catheter migration may be more frequent with early-start PD but does not appear to impact technique survival.
Female ; Humans ; Kidney Failure, Chronic/therapy* ; Male ; Peritoneal Dialysis/methods* ; Renal Dialysis ; Retrospective Studies ; Time Factors