Short-term in vitro exposure of Pinctada imbricata's haemocytes to quaternium-15: Exploring physiological and cellular responses.

Since the 2000 s, the pearl oyster Pinctada imbricata (Röding, 1798) has become established along the transitional waterways of the "Capo Peloro Lagoon" natural reserve, where it is now abundant due to its adaptability to different hydrological, climatic, environmental, and pollution conditions. This study aims to evaluate haemocyte immune-mediated responses in vitro to quaternium-15, a common pollutant in aquatic ecosystems. Cell viability and phagocytosis activity decreased when exposed to 0.1 or 1 mg L- 1 of quaternium-15. Moreover, decreasing phagocytosis was confirmed by gene expression modulation of actin, involved in cytoskeleton rearrangement. Effects on oxidative stress-related genes were also assessed (Cat, MnSod, Zn/CuSod, GPx). The qPCR data revealed alterations in antioxidant responses through gene dose- and time-dependent modulation. This study presents insights into the physiological responses and cellular mechanisms of P. imbricata haemocytes to environmental stressors, indicating that this species is useful as a novel bioindicator for future toxicological studies.

In-hospital mortality of very preterm infants in a Tunisian neonatal intensive care unit: Prevalence and risk factors.

BACKGROUND: Prematurity is a major public health problem and it's associated with a high mortality and morbidity. In Tunisia, few investigations studied this area. AIM: To determine the rate and the risk factors of in-hospital mortality of very preterm infants. METHODS: We conducted a retrospective monocentric study. We included all premature Infants born at less than 326 weeks of gestation (< 33 Weeks) without major congenital anomalies admitted from January 2011 to December 2012 in the neonatal intensive care unit (NICU) of Charles Nicolle Hospital (Tunis-Tunisia). To determine in-hospital mortality related risk factors, we created and compared two groups:  group of "Survivors" until discharge from our hospital and group of "Dead" before discharge. Multivariable logistic regression models were used to assess the association between risk factors and in-hospital mortality. P-value < 0.05 was considered statistically significant. RESULTS: During the study period, 7606 livebirths (LB) were recorded; among them 113 were very premature infants. The prevalence of high prematurity was 1,4 % LB. Very premature infants were divided in 24 extremely preterm infant (13%) and 89 moderately preterm infants (87%). Mean weight at admission was 1338g (±349g) and the mean gestational age was 30 weeks (±1,7). The mean hospital stay was 26 days (±17days) with an average weight at discharge of 1942g (±249). Neonatal morbidity was mainly caused by respiratory distress (42%), early neonatal anemia (64%), intraventricular hemorrhagea (15%), associated-care health infection (37,6%). In hospital mortality rate was 32 %. Mortality risk factors identified through multivariate analysis were: extreme premature infant (p<0,05), extremely low birth weight (p<0,01) and circulatory disorders (p<0,05). CONCLUSION: Very preterm infant represented 1,4 % of all live births. The mortality rate of very premature infant is still high and mainly associated to neonatal respiratory distress. Improving prevention and neonatal management still very required.