[Functional MRI assessment of microstructural and perfusion changes in the kidneys of rats with intrauterine growth restriction]. / åŠŸèƒ½ç£å ±æŒ¯è¯„ä¼°å®«å† å‘è‚²è¿Ÿç¼“ä»”é¼ è‚¾è„å¾®è§‚ç»“æž„åŠçŒæ³¨æ”¹å˜.

OBJECTIVES: To explore the value of functional magnetic resonance imaging (MRI) techniques, including intravoxel incoherent motion (IVIM), T1 mapping, and T2 mapping, in assessing the microstructural and perfusion changes in the kidneys of rats with intrauterine growth restriction (IUGR). METHODS: An IUGR rat model was established through a low-protein diet during pregnancy. Offspring from pregnant rats on a low-protein diet were randomly divided into an IUGR 8-week group and an IUGR 12-week group, while offspring from pregnant rats on a normal diet were divided into a normal 8-week group and a normal 12-week group (n=8 for each group). The apparent diffusion coefficient (ADC), true diffusion coefficient (Dt), pseudo-diffusion coefficient (D*), perfusion fraction (f), T1 value, and T2 value of the renal cortex and medulla were compared, along with serum creatinine and blood urea nitrogen levels among the groups. RESULTS: The Dt value in the renal medulla was higher in the IUGR 12-week group than in the IUGR 8-week group, and the D* value in the renal medulla was lower in the IUGR 12-week group than in both the normal 12-week group and the IUGR 8-week group (P<0.05). The T1 value in the renal medulla was higher than in the cortex in the IUGR 8-week group, and the T1 value in the renal medulla was higher in the IUGR 12-week group than in both the IUGR 8-week group and the normal 12-week group, with the cortical T1 value in the IUGR 12-week group also being higher than that in the normal 12-week group (P<0.05). The T2 values in the renal medulla were higher than those in the cortex across all groups (P<0.05). There were no significant differences in the T2 values of either the cortex or medulla among the groups (P>0.05). There were no significant differences in serum creatinine and blood urea nitrogen levels among the groups (P>0.05). Glomerular hyperplasia and hypertrophy without significant fibrotic changes were observed in the IUGR 8-week group, whereas glomerular atrophy, cystic stenosis, and interstitial inflammatory infiltration and fibrosis were seen in the IUGR 12-week group. CONCLUSIONS: IVIM MRI can be used to assess and dynamically observe the microstructural and perfusion damage in the kidneys of IUGR rats. MRI T1 mapping can be used to evaluate kidney damage in IUGR rats, and the combination of MRI T1 mapping and T2 mapping can further differentiate renal fibrosis in IUGR rats.

The timing of withdrawal from caffeine citrate in very preterm infants. / æžæ—©æ—©äº§å„¿æž¸æ©¼é ¸å’–å•¡å› åœç”¨æ—¶æœºçš„ä¸´åºŠç ”ç©¶.

OBJECTIVES: To study the clinical features and outcome of very preterm infants withdrawn from caffeine citrate at different time points. METHODS: A retrospective analysis was performed on the medical data of the preterm infants with a gestational age of <32 weeks, who were hospitalized in the Division of Neonatology, the Second Xiangya Hospital of Central South University, from January 1, 2016 to November 30, 2020. According to the time of withdrawal from caffeine citrate, the infants who met the study criteria were divided into the group with withdrawal before the last week of hospitalization and the group with withdrawal within the last week of hospitalization. The two groups were compared in terms of clinical features, features of citric caffeine use, length of hospital stay and hospital costs, change in the intensity of respiratory support, and preterm complications. RESULTS: A total of 403 preterm infants were enrolled, with 285 infants in the group with withdrawal before the last week of hospitalization and 118 infants in the group with withdrawal within the last week of hospitalization. There were no significant differences in clinical features between the two groups (P>0.05). Compared with the group with withdrawal before the last week of hospitalization, the group with withdrawal within the last week of hospitalization had a significantly longer duration of the use of caffeine citrate, a significantly shorter length of hospital stay, a significantly lower rate of increased intensity of respiratory support after withdrawal, and a significantly lower incidence rate of moderate or severe bronchopulmonary dysplasia (P<0.05). CONCLUSIONS: A relatively long course of caffeine citrate treatment is more beneficial to the short-term clinical outcome of very preterm infants.