Search

Objective: To study the extent of retinal vascular development and influencing factors at birth and the relation between retinal vascularization and retinopathy of prematurity (ROP)., Methods: From October, 2006 to December 2006, retinal vascularization was screened and evaluated in 84 neonates at different weeks of gestation and birth weights (BWs), had dilated fundus evaluation for zone of retinal vascularization by the 130 degrees lens of a digital fundus camera. The infants' pupils were dilated with 2.5% phenylephrine and 0.5% cyclopentolate eye drops. The study cohort was divided into subgroups depending on the weeks of gestation and birth weights. The control group consisted of healthy term infants. Maternal and neonatal factors were ascertained and analysed., Results: Vascularization up to zone I and II was considered to be immature retina; vascularization up to zone III or beyond was considered to be mature retina. In this study, 11 of 12 infants who were born at < 30 weeks of gestation, 12 of 26 infants who were born at < 31 approximately 33 weeks of gestation, 1 of 26 babies who were born at < 34 approximately 36 weeks of gestation and none of 20 babies who were born at < 37-40 weeks of gestation had immature retina; 12 of 15 babies at < 1500 g BW, 8 of 14 infants at 1500 g < BW < 1700 g, 4 of 11 infants at 1700 g < BW < 2000 g and of 44 infants at > 2000 g BW had immature retina. Those infants who were born at > 34 weeks of gestational age and at > 2000 g BW had mature retina. Infants who were born between 31 to 34 weeks of gestation and at 1501 to 2000 g BW had variable extent of retinal vascularization at birth. Vascularization was associated with postconceptional age (F = 31.9193, P = 0.000), birth weight (F = 32.4532, P = 0.000), anemia (F = 36.9391, P = 0.000), surfactant (F = 24.000, P = 0.0000), poor nutrition (F = 4.184, P = 0.041), RDS (F = 17.6191, P = 0.000), cesarean delivery (F = 10.972, P = 0.0022) and oxygen > 48 h (F = 22.076, P = 0.0000). Vascularization was affected mainly by the postconceptional age (95% CI = 1.57-261.728, P = 0.021). At last, 15/24 infants with immature retina developed ROP while none of the infants with mature retina developed ROP (chi2 = 45.1087, P = 0.000)., Conclusion: There is considerable variability in the extent of retinal vascularization in infants who we born between 31 to 34 weeks of gestation. Modifiable maternal and fetal factors could influence extent of vascularization at birth. Immature retina is the critical factor of ROP. Gestational age is the main factor of the immature retina in premature infants.

Objective: To investigate possible relationship between expression of surfactant protein B (SP-B) gene product and neonatal respiratory distress syndrome (NRDS) in Han ethnic group., Method: Unrelated 20 cases with NRDS of Han ethnic group were selected as NRDS group while unrelated 20 diseases cases of Han ethnic group with diseases were selected as control group. The cases in the control group had congenital heart disease or bronchopulmonary dysplasia or persistent pulmonary hypertension. Blood sample was taken from every case. Lung tissues were taken from the patients who died half an hour after death in the two groups. Expression of SP-B in lung tissue was determined with immunohistochemical tecnique. Genetic deficiency variant of SP-B intron IV was screened with polymerase chain reaction (PCR)., Results: Two cases at gestational age 26 weeks and one case at gestational age 34 weeks and two cases at gestational age 42 weeks of NRDS groups had lower level expression of SP-B in lung tissue than those at the same age of NRDS. Expression of SP-B in lung tissue of control group increased with gestational age, but no such phenomenon was found in NRDS group. Further, two cases at gestational age 42 weeks of NRDS group had genetic deficiency variant of SP-B intron IV with gene analysis of five cases who had lower expression of SP-B. Clinical data suggest that patients at 42 weeks of gestational age had severe illness., Conclusions: Decrease of SP-B expression may participate in occurrence of NRDS, genetic deficiency variant of SP-B intron IV exists in the NRDS cases of Han ethnic group of China.

Objective: To investigate the prevalence and risk factors of retinopathy of prematurity (ROP)., Methods: This investigation involved 125 premature infants admitted in the neonate intensive unit between July 1st, 2006 and Feb 1st, 2007, who were less than 37 weeks of postconceptional age, or more than 37 weeks but with birth weight <2500 g. At the fourth postnatal week or the corrected gestational age of 32 to 34 weeks, the infants underwent ROP examination of both eyes using RetCam digital retinal camera. Diagnosis and staging of ROP were established according to the international guidelines, with another 20 full-term infants as the control group., Results: All the 125 infants completed the follow up. The prevalence of ROP in the premature group was 6.4%, while no ROP was found in the control group. Of the premature infants, the prevalence of ROP in infants with birth weight

The registration method based on mutual information is currently a popular technique for the medical image registration, but the computation for the mutual information is complex and the registration speed is slow. In engineering process, a subsampling technique is taken to accelerate the registration speed at the cost of registration accuracy. In this paper a new method based on statistics sample theory is developed, which has both a higher speed and a higher accuracy as compared with the normal subsampling method, and the simulation results confirm the validity of the new method.