To interpret the flash evoked potential (FVEP) as dynamic high-order responses to natural and experimental stimulation in healthy preterm infants, waveform analysis of FVEP in 36 healthy preterm infants (postconceptional age 28~42 weeks) were performed using an autoregressive analysis. Based on the histogram of damping frequency of different component impulse response waveforms, the waveforms were divided into 4 groups: group I (0 ~ <2 Hz), group II (2 ~ <6.5 Hz), group III (6.5 ~ <12.0 Hz) and group IV (12~25 Hz). The total power, power of component impulse responses (group I~IV), and damping time (group II~IV) changed significantly with increasing postconceptional age (P<0.01 or P<0.05). Identification of an impulse response component with dominant frequency which undergoes a well-identified change with age is considered to be a useful tool for discriminating between normal and abnormal changes in the FVEP with age in healthy preterm infants.
Evoked Potentials, Visual ; physiology ; Female ; Humans ; Infant, Newborn ; Infant, Premature ; physiology ; Male ; Reaction Time ; Sleep ; physiology

OBJECTIVETo investigate the characteristics of the tidal breathing pulmonary function in premature infants with different gestational ages.

METHODSA total of 75 premature infants were classified into three groups according to their gestational ages: <32 weeks, 32-33(+6) weeks and 34-36(+6) weeks. Fifty-five full-term infants (39-40 weeks group) were selected as the control group. All infants were given the tidal breathing pulmonary function test at 3-5 days after birth. Moreover, all infants were given the tidal breathing pulmonary function test again at 40 weeks of the corrected gestational age.

RESULTSAt 3-5 days after birth, the three groups of premature infants had significantly lower inspiratory time, time to peak tidal expiratory flow (tPTEF), and ratio of tPTEF to total expiratory time (tPTEF/tE) than the control group (P<0.05). The parameter values of the tidal breathing pulmonary function were lower when the gestational age was lower. Even at 40 weeks of the corrected gestational age, the three groups of premature infants still had significantly lower tPTEF and tPTEF/tE than the control group (P<0.05).

CONCLUSIONSThe tidal breathing pulmonary function of neonates is influenced by the gestational age. The tidal breathing pulmonary function of premature infants is obviously impaired, and the lower the gestational age, the more obvious the impairment.

Female ; Gestational Age ; Humans ; Infant, Newborn ; Infant, Premature ; physiology ; Lung ; physiology ; Male ; Pregnancy ; Respiration

OBJECTIVELeptin is an adipocyte-derived hormone regulating body weight and energy balance in animals and human being. Although the physiological functions of leptin in human are still unclear, its secretion is closely related to fat mass and energy expenditure in both adults and children. This study investigated whether the plasma leptin level was reduced in connection with the weight loss during the neonatal period and try to find out the role of leptin in body weight regulation and energy balance of premature infants.

METHODSThe radioimmunoassay was used to determine the plasma leptin concentration. The first blood samples were obtained at the delivered, and then collected the samples every two days until the infants' body weight recovered to the birth weight or above. At the same time, the essential fluid and energy for the patients were supplied to keep their physiological functions. One person was appointed to take responsibility to examine the body weight, body length and head circumference. Then computed out their Kaup index from the first day to the seventh or twelfth day.

RESULTSA total of 26 premature infants were selected into the study, of which 14 cases were male and 12 female, and their gestational age ranged from 30 to 36 weeks. There was a significantly positive correlation between the premature newborns' body weight loss and their plasma leptin levels (the 1st day: n = 26, r = 0.766; the 3rd day: n = 26, r = 0.636; the 5th day: n = 26, r = 0.629; the 7th day: n = 26, r = 0.717; the 9th-12th day: n = 24, r = 0.587; P < 0.01). The time of body weight loss and the plasma leptin level which declined to extremely low were positively correlated. (r = 0.611, P < 0.01). The time when body weight loss declined to extremely low in 26 premature infants ranged form the 3rd to the 9th day after birth [(5.2 +/- 1.6) day], and that of the plasma leptin levels ranged form the 3rd to the 8th day after birth (4.7 +/- 1.4) day. The maximal ranges of the body weight loss and the plasma leptin decrease in 26 premature infants were (6.5 +/- 3.0)% and (59.6 +/- 11.3)%, respectively. In addition, there were significantly positive correlations among the plasma leptin level, the premature newborns' body length (the 1st day: n = 26, r = 0.609, P < 0.01; the 3rd day: n = 26, r = 0.419, P < 0.05; the 5th day: n = 26, r = 0.583, P < 0.01; the 7th day: n = 26, r = 0.626, P < 0.01; the 9th-12th day: n = 24, r = 0.482; P < 0.05), and the Kaup index (the 1st day: n = 26, r = 0.634; the 3rd day: n = 26, r = 0.534; the 5th day: n = 26, r = 0.542; the 7th day: n = 26, r = 0.611; the 9th-12th day: n = 24, r = 0.539; P < 0.01). Although the head circumference correlated positively with the plasma leptin level at the first week after the delivery (the 1st day: n = 26, r = 0.580, P < 0.01; the 3rd day: n = 26, r = 0.417, P < 0.05; the 5th day: n = 26, r = 0.426; P < 0.01). There was a lower correlation between them one week after the delivery (the 7th day: n = 26, r = 0.369; the 9th-12th day: n = 24, r = 0.323; P > 0.05).

CONCLUSIONThere was a significantly positive correlation between the plasma leptin level and the premature newborns weight loss. Leptin may participate in the regulation of energy balance and body weight of premature infants during neonatal life. Leptin may play an important role in growth and development of premature infants.

Body Weight ; physiology ; Humans ; Infant, Newborn ; Infant, Premature ; Leptin ; blood ; Radioimmunoassay ; Time Factors ; Weight Loss ; physiology

OBJECTIVETo explore the relation of the anogenital distance (AGD) with cryptorchidism in male newborns.

METHODSThis study included 350 male infants delivered in two community hospitals between September 2013 and September 2014. Within 24 hours after birth, a pediatric surgeon measured the AGD of the neonates and determined whether they had cryptorchidism. According to the testicular position, we divided the undescended testes into three types: upper scrotal, inguinal, and non-palpable.

RESULTSTotally 39 cases of cryptorchidism were found in the 350 newborns. The AGD of the cryptorchidism infants was significantly shorter than that of the normal neonates ([2.01 ± 0.22] vs [2.35 ± 0.19] cm, P < 0.01), and statistically significant differences remained even when preterm and low birth-weight infants were excluded ([2.32 ± 0.14] vs [2.06 ± 0.19] cm; (2.37 ± 0.17) cm vs (2.12 ± 0.12) cm, all P < 0.01). The newborns with higher-position cryptorchidism had a shorter AGD, though with no significant difference (F = 0.434, P > 0.05). No significant differences were observed in the AGD between unilateral and bilateral cryptorchidism ([1.96 ± 0.13] vs [2.02 ± 0.17] cm, P > 0.05).

CONCLUSIONShorter AGD is associated with a higher incidence of cryptorchidism in male newborns. AGD could serve as a potential biomarker for disruption of androgen action during the male programming window period.

Androgens ; physiology ; Cryptorchidism ; diagnosis ; Humans ; Infant, Low Birth Weight ; Infant, Newborn ; Infant, Premature ; Male ; Perineum ; abnormalities

OBJECTIVEInadequate postnatal nutritional support is an important factor contributing to growth failure, which leads to poor neurological outcome. In this study, co-word analysis was used to investigate the research on nutrition of premature infants over the last six years in China, describe the research trend in this field in China, and provide possible directions for future research.

METHODSA literature search was performed in January 2013 using the CNKI database and the key words "preterm infant" and "nutrition". A total of 772 articles were retrieved. Then high-frequency key words were extracted using Excel 2010 to create a co-occurrence matrix. Finally, a visualized network was built using Ucinet 6.0.

RESULTSThe knowledge domain map of research on nutritional support for premature infants in China showed that the major topic of relevant research is still the combination of parenteral nutrition and enteral nutrition, with the goal of maintaining appropriate growth rates in premature infants. Researchers have paid much attention to the adverse effects of parenteral nutrition. Feeding intolerance is still the main problem in nutritional support, especially enteral nutrition, for premature infants.

CONCLUSIONSA visualized network of current research on nutrition of premature infants in China has been created, and a knowledge domain map has been drawn to reflect the hot topics in this field of study over the last six years.

Enteral Nutrition ; Humans ; Infant Nutritional Physiological Phenomena ; Infant, Newborn ; Infant, Premature ; physiology ; Parenteral Nutrition

INTRODUCTION: Neonatal care advances have resulted in improved survival but have raised concerns of increase in neurodevelopmental impairment. This study looked at long-term neurodevelopmental outcomes at ages 5 and 8 years of very low birthweight infants born in the 2000s as compared to the 1990s. Neurodevelopmental assessment at 2 years old was compared to that at 5 and 8 years to determine if assessment at 2 years was predictive of later outcomes. MATERIALS AND METHODS: A retrospective cohort study of consecutive infants with birthweight less than 1250 grams admitted to a tertiary centre in Singapore between January 1994 to December 1995 (Epoch I) and January 2004 to December 2005 (Epoch II) were included. Neurodevelopmental impairment was defined as having intelligence quotient (IQ) of less than 70, cerebral palsy, legal blindness, or hearing impairment requiring hearing aids. RESULTS: Mean gestational age was lower for Epoch II compared to Epoch I (28.1 ± 2.5 vs 29.4 ± 2.7 weeks, = 0.004). Death or neurodevelopmental impairment rates did not differ (24.3% and 17.1% at 5 years old, = 0.398; 29.1% and 25.0% at 8 years old, = 0.709). There was improvement in visual impairment rate at 8 years in Epoch II (10.7% vs 34.0%, = 0.024). Mean IQ was better in Epoch II (109 and 107 vs 97 and 99 at 5 [ = 0.001] and 8 years [ = 0.047], respectively). All infants with no neurodevelopmental impairment at 2 years remained without impairment later on. CONCLUSION Over a decade, neurodevelopmental outcomes did not worsen despite lower mean gestational age. Long- term improvement in IQ scores and a reduction in visual impairment rates were seen. Our data suggests that children without neurodevelopmental impairment at 2 years are without impairment later on; therefore, they may need only developmental monitoring with targeted assessments instead of routine formal IQ assessments.
Child ; Child, Preschool ; Humans ; Infant, Newborn ; Infant, Premature ; physiology ; Infant, Very Low Birth Weight ; physiology ; Neurodevelopmental Disorders ; etiology ; Singapore

Continuous Positive Airway Pressure ; Female ; Fetus ; physiology ; Humans ; Infant, Newborn ; Infant, Premature ; physiology ; Lung ; physiology ; Obstetric Labor, Premature ; therapy ; Oxygen ; blood ; Pregnancy

Cerebral Cortex ; growth & development ; physiology ; Evoked Potentials, Visual ; physiology ; Humans ; Infant, Newborn ; Infant, Premature ; growth & development ; Sensory Thresholds ; physiology ; Vision, Ocular ; physiology ; Visual Acuity ; physiology ; Visual Perception ; physiology

OBJECTIVETo study the background patterns and sleep-wake cycles (SWC) on amplitude-integrated electroencephalography (aEEG) in preterm infants with different grades of periventricular-intraventricular hemorrhage (PIVH).

METHODSFifty-six preterm infants with a gestational age between 25 and 33 weeks who were diagnosed with PIVH and 31 gestational age-matched normal preterm without ICH were enrolled. According to Papile staging criteria, the infants with PIVH were subdivided into mild group (grades I and II) and moderate-severe group (grades III and IV). The results of the aEEG were compared between groups.

RESULTSThe moderate-severe PIVH group showed a decreased continuity of the voltage, an increased loss rate of SWC, and a lower aEEG score than the mild PIVH and control groups (P<0.017). There were no significant differences in these parameters between the mild PIVH and control groups.

CONCLUSIONSThe changes of background patterns and SWCs may be associated with the severity of PIVH in preterm infants.

Cerebral Hemorrhage ; physiopathology ; Electroencephalography ; Female ; Humans ; Infant, Newborn ; Infant, Premature ; Male ; Sleep ; physiology

OBJECTIVETo study the postnatal changes in lymphocyte subsets in early preterm infants and the effect of perinatal factors on lymphocyte subsets.

METHODSA total of 61 early preterm infants were enrolled. Flow cytometry was used to measure the absolute counts of lymphocytes and lymphocyte subsets at 1, 7, 14, and 28 days after birth, as well as at 6 months after birth for 17 of these early preterm infants. The effects of perinatal factors, such as antepartum use of hormone, intrauterine infection, gestational age at birth, and Ureaplasma urealyticum (UU) colonization, on lymphocyte subsets were analyzed.

RESULTSThe absolute counts of lymphocyte subsets except natural killer (NK) cells were lowest at birth, increased rapidly at 1 week after birth, and reached the levels in healthy infants at 6 months; the count of NK cells remained at a low level and increased significantly at 6 months after birth. Compared with those with a gestational age of <28 weeks, the early preterm infants with a gestational age of ≥28 weeks had significantly higher absolute counts of T cells, T helper (Th) cells, and NK cells at 7 days after birth, a significantly higher absolute count of T cells at 14 days after birth, and significantly higher absolute counts of lymphocytes and Th cells at 28 days after birth (P<0.05). Compared with the group not using hormone, the group using hormone showed a significantly higher absolute count of T cells at 7 days after birth and significantly higher absolute counts of lymphocytes and all subsets at 14 days after birth (P<0.05). There was no significant difference in lymphocyte subsets at 1 day after birth between the intrauterine infection and non-infection groups (P>0.05); the intrauterine infection group had significantly higher absolute counts of B cells at 7 and 14 days after birth than the non-infection group. Compared those without UU colonization, the infants with UU colonization had significantly higher absolute counts of lymphocytes, T cells, Th cells, and Ts cells at 1 day after birth and a significantly higher absolute count of B cells at 14 days after birth.

CONCLUSIONSEarly preterm infants have deficiencies in innate immune cells at birth and normal levels at about 6 months after birth. Various perinatal factors including antepartum use of hormone, gestational age at birth, intrauterine infection, and UU colonization have long-term effects on lymphocyte subsets in early preterm infants.

Female ; Humans ; Infant, Newborn ; Infant, Premature ; immunology ; Lymphocyte Subsets ; microbiology ; physiology ; Male ; Ureaplasma urealyticum ; isolation & purification