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OBJECTIVE: To analyze the related risk factors in blood transfusions for extremely low birth weight infants and extreme preterm infants, and to explore the prevention strategy of anemia. METHODS: A total of 60 infants with gestational age < 28 weeks or birth weight < 1000 g admitted to our hospital from January 2017 to December 2020 were retrospectively analyzed. The infants with a birth weight of less than 1000 g were divided into the blood transfusion group and the non-blood transfusion group according to whether they received a blood transfusion. The general health situation, disease occurrence and treatment measures during hospitalization were compared between the two groups, and the risk factors of blood transfusion were analyzed. RESULTS: There were significant differences in maternal anemia during pregnancy, birth weight, gestational age, hemoglobin and hematocrit at birth, blood collection within 2 weeks after birth, length of hospital stay, bronchopulmonary dysplasia and patent ductus arteriosus between the transfusion group and the non-transfusion group (P < 0.05). Multivariate logistic regression analysis and ROC curve analysis showed that the younger the gestational age (OR=0.385, 95% CI: 0.212~0.705, P=0.002), the lower the birth weight (OR=1.004, 95% CI: 0.967~0.998, P=0.001), the longer the hospitalization time (OR=2.178, 95% CI: 1.172~4.049, P=0.014) and a larger blood collection within 2 weeks after birth (OR=1.269, 95% CI: 1.084~1.489, P=0.003) would induce higher the blood transfusion rates. CONCLUSION: The transfusion indications of extremely low birth weight infants and extreme preterm infants are affected by many factors, among which gestational age, length of hospital stay, blood collection within 2 weeks after birth and birth weight are independent predictors of transfusion. Blood transfusion in extremely low birth weight infants and extreme preterm infants is associated with an increased risk of apnea, neonatal respiratory distress syndrome, bronchopulmonary dysplasia and patent ductus arteriosus.
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Viral vector transfection systems are among the simplest of biological agents with the ability to transfer genes into the central nervous system. In brain research, a series of powerful and novel gene editing technologies are based on these systems. Although many viral vectors are used in rodents, their full application has been limited in non-human primates. To identify viral vectors that can stably and effectively express exogenous genes within non-human primates, eleven commonly used recombinant adeno-associated viral and lentiviral vectors, each carrying a gene to express green or red fluorescence, were injected into the parietal cortex of four rhesus monkeys. The expression of fluorescent cells was used to quantify transfection efficiency. Histological results revealed that recombinant adeno-associated viral vectors, especially the serotype 2/9 coupled with the cytomegalovirus, human synapsin I, or Ca2+/calmodulin-dependent protein kinase II promoters, and lentiviral vector coupled with the human ubiquitin C promoter, induced higher expression of fluorescent cells, representing high transfection efficiency. This is the first comparison of transfection efficiencies of different viral vectors carrying different promoters and serotypes in non-human primates (NHPs). These results can be used as an aid to select optimal vectors to transfer exogenous genes into the central nervous system of non-human primates.