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Biomedical subjects

R J Teng

Publications and source records attributed to R J Teng.

At least 19 recordsLinked to original sources
PubMed2000

Superoxide reacts with nitric oxide to nitrate tyrosine at physiological pH via peroxynitrite.

Tyrosine nitration is a widely used marker of peroxynitrite (ONOO(-)) produced from the reaction of nitric oxide with superoxide. Pfeiffer and Mayer (Pfeiffer, S., and Mayer, B. (1998) J. Biol. Chem. 273, 27280-27285) reported that superoxide produced from hypoxanthine plus xanthine oxidase in combination with nitric oxide produced from spermine NONOate did not nitrate tyrosine at neutral pH. They suggested that nitric oxide and superoxide at neutral pH form a less reactive intermediate distinct from preformed alkaline peroxynitrite that does not nitrate tyrosine. Using a stopped-flow spectrophotometer to rapidly mix potassium superoxide with nitric oxide at pH 7.4, we report that an intermediate spectrally and kinetically identical to preformed alkaline cis-peroxynitrite was formed in 100% yield. Furthermore, this intermediate nitrated tyrosine in the same yield and at the same rate as preformed peroxynitrite. Equivalent concentrations of nitric oxide under aerobic conditions in the absence of superoxide did not produce detectable concentrations of nitrotyrosine. Carbon dioxide increased the efficiency of nitration by nitric oxide plus superoxide to the same extent as peroxynitrite. In experiments using xanthine oxidase as a source of superoxide, tyrosine nitration was substantially inhibited by urate formed from hypoxanthine oxidation, which was sufficient to account for the lack of tyrosine nitration previously reported. We conclude that peroxynitrite formed from the reaction of nitric oxide with superoxide at physiological pH remains an important species responsible for tyrosine nitration in vivo.

Hydrogen-Ion Concentration↗
PubMed2000

A model to study antioxidant regulation of endotoxemia-modulated neonatal granulopoiesis and granulocyte apoptosis.

Neonates with septicemia tend to develop granulocytopenia, which may, in part, be due to septic mediators such as oxygen free radicals and tumor necrosis factor alpha (TNF-alpha). Granulocytopenia may be caused by a decrease in granulocyte growth and/or an increase in granulocyte destruction. In the present study, we investigated antioxidant regulation of endotoxin-modulated neonatal granulopoiesis and granulocyte apoptosis. Using human umbilical cord blood (HUCB), we found that simulating endotoxemia in vitro elicited significant superoxide production within a few minutes. Endotoxin exposure suppressed colony-forming unit-granulocyte and monocyte formation in a dose-dependent fashion. Addition of antioxidants such as N-acetyl-cysteine could reverse the endotoxin suppression of colony-forming unit-granulocyte and monocyte formation (13 +/- 5 versus 75 +/- 5 colony-forming units/mL). Spontaneous in vitro granulocyte apoptosis in 6 h, as reflected by phosphatidylserine expression on the cell surface, was higher in granulocytes from HUCB than in those from adult blood (10.8 +/- 1.0% versus 5.6 +/- 1.2%). The addition of endotoxin or IL-8 to the cells in the in vitro model did not promote granulocyte apoptosis, but TNF-alpha, a major mediator of the effects of endotoxin, significantly induced granulocyte apoptosis in HUCB (control versus TNF-alpha: 8.9 +/- 1.2% versus 35.9 +/- 2.9%). Addition of the antioxidant N-acetyl-cysteine effectively blocked TNF-alpha-induced granulocyte apoptosis as demonstrated by DNA fragmentation. Results from these studies indicate that oxygen radicals are directly involved in endotoxin suppression of granulopoiesis, and indirectly promote granulocyte apoptosis, presumably through TNF-alpha-mediated action. Thus, under certain conditions, modulation of oxygen radical production in the blood may benefit neonates with granulocytopenia.

Acetylcysteine↗
PubMed1999

Granulocyte colony-stimulating factor in the cord blood of premature neonates born to mothers with pregnancy-induced hypertension.

OBJECTIVES: To estimate the cord blood levels of granulocyte colony-stimulating factor (G-CSF) and granulocyte-macrophage colony-stimulating factor (GM-CSF) in preterm infants and to study the relationship of these levels to pregnancy-induced hypertension (PIH) and absolute neutrophil counts. STUDY DESIGN: G-CSF and GM-CSF levels in the cord blood of preterm neonates (n = 74) either with or without maternal PIH were estimated by enzyme-linked immunosorbent assay. RESULTS: Infants in the PIH group had lower white blood cell, absolute neutrophil, absolute lymphocyte, and monocyte counts. The levels of G-CSF in cord blood were significantly lower in infants whose mothers had PIH (P =.04) and in infants with neutropenia (P =. 01). G-CSF levels were positively correlated with both absolute neutrophil count (P =.02) and total white blood cell count (P =.01). GM-CSF was undetectable in all subjects. According to logistic regression with neutropenia as the dependent variable, only maternal PIH (P <.001), gestational age (P <.001), and G-CSF (P =.01) were independently related. CONCLUSION: In this study maternal PIH and low gestational age were significantly associated with neutropenia in premature infants. Low G-CSF levels may contribute to the neutropenia that is commonly seen in infants born to mothers with PIH.

Case-Control Studies↗
PubMed1998

Neurobehavioral development at term in very low-birthweight infants and normal term infants in Taiwan.

We compared the neurobehavioral performance at term between very low-birthweight (VLBW) infants and term infants in Taiwan, and investigated the relationships between neonatal factors and neurobehavioral performance in VLBW infants. Sixty VLBW infants and 58 healthy term infants were examined using the Neonatal Neurobehavioral Examination-Chinese version (NNE-C) at 40 weeks postmenstrual age. Medical records of the VLBW infants were reviewed to assess neonatal factors. The mean total score of the preterm infants (67.4+/-5.0) was significantly lower than that of the term infants (73.8+/-3.0) (t = 8.51, P < 0.0001). Furthermore, respiratory illness had a marginal effect on the rate of low neurobehavioral score (defined as 2SD below the mean score of term infants) in the preterm infants after adjustment for gestational age (odds ratio = 7.67, chi2 = 3.36, P = 0.067). Our findings indicate that preterm infants have lower neurobehavioral scores at term than their healthy term counterparts. Furthermore, respiratory illness may be a potential risk factor for low neurobehavioral score at term in preterm infants when gestational age is adjusted for.

Apgar Score↗
PubMed1998

Jacobsen distal 11q deletion syndrome with a myelodysplastic change of hemopoietic cells.

We describe a male infant with unusual facial appearance, relative pancytopenia, bilateral simian creases, and an accessory nipple. Cytogenetic analysis showed deletion of the long arm of chromosome 11 [46,XY,del(11)(pter-->q23.2:)]. Bone-marrow study showed a myelodysplastic change of hemopoietic cells compatible with peripheral blood findings. Pachygyria of the temporal and frontal lobes was demonstrated by magnetic resonance image (MRI) of the brain. We present our findings in order to contribute to the information on 11q23 deletion.

Bone Marrow Cells↗
PubMed1998

Successful arterial switch operation in a low-birth-weight neonate who had transposition of the great arteries and advanced necrotizing enterocolitis.

A low-birth-weight (LBW; 1,940 g) girl was born at the gestational age of 36 weeks without any perinatal insult. Transposition of the great arteries (TGA) with a large patent ductus arteriosus (PDA) and interatrial shunt was detected. Stage IIIB necrotizing enterocolitis (NEC) developed 46 hours after birth. She received ileostomy and drainage. Arterial switch operation was successfully performed at 23 days of age when her weight was 1,900 g. The enterostomy was successfully repaired at 104 days of age.

Ductus Arteriosus, Patent↗
PubMed1998

The human tail.

The human tail is a congenital anomaly with a protruding lesion from the lumbosacrococcygeal region. A newborn with a tail-like structure over the coccygeal area observed since birth is presented. Lipoma accompanied by tethered spinal cord were found. In reviewing the literature from 1960 to 1997, 59 cases were described. Higher incidences of spinal dysraphism (49.15%) and tethered spinal cord (20.34%) compared with previous reports were evident. This fact plays an important role in understanding the disturbance of development and regression of human tails. A new classification according to whether the anomaly appears in combination with spinal dysraphism is proposed for clinical usage. Preoperative detailed image studies are needed to clarify the possibility of tethered spinal cord syndrome developing in the future and thus prevent it. Magnetic resonance imaging is the modality of choice if available. Long-term follow-up for possible sequelae after operation, especially in cases with spinal dysraphism, is necessary.

Animals↗
PubMed1998

Long QT syndrome manifested as fetal ventricular tachycardia and intermittent AV block.

A case of long QT syndrome diagnosed in the early neonatal period is described. This full-term female baby had intermittent atrioventricular (AV) block and ventricular tachycardia detected antenatally at the gestational age of 26 weeks. Sinus rhythm with prolonged QT interval (QTc = 0.636 sec) was found soon after birth. She developed variable degree of AV block with alternating left and right bundle branch block, which suggested the presence of multilevel AV block. Her mother had no lupus autoantibodies. Auditory brain stem evoked potential was normal. Family study revealed QT prolongation in her grandmother. Her condition improved after pacemaker implantation and oral beta-blocker usage.

Electrocardiography↗
PubMed1998

Correlation between urinary epidermal growth factor excretion and serum thyroid hormone in premature and term neonates.

Eighty neonates, including 14 full-term, 31 premature, 27 twin or triplet, 6 small-for-gestational-age, and 2 infants with hyperthyroidism, were evaluated. The urinary epidermal growth factor/creatinine ratio (EGF/Cr) on the 1st postnatal day was not statistically different among full-term, premature, multiple-pregnancy, and small-for-gestational-age infants (F = 1.06, p = 0.6). There was no difference in urinary EGF/Cr between the 1st postnatal day and the 7th day (p = 0.4 by paired t test). The urinary EGF/Cr was not correlated with the serum thyroid-stimulating hormone level (r = -0.162, n = 60, p = 0.21), but showed a positive correlation with serum total T3 (r = 0.526, n = 60, p < 0.001) and with serum total T4 (r = 0.460, n = 60, p < 0.001). The correlation between urinary EGF/Cr and serum free T4 was even much better (r = 0.727, n = 25, p < 0.001). These results implicate that thyroid hormone may play a role in regulating urinary EGF excretion.

Creatinine↗
PubMed1998

Etiology and outcome of hydrops fetalis.

Hydrops fetalis is a morbid condition caused by a wide variety of diseases. Although treatment for some underlying pathologies is becoming available, the prognosis remains poor. To analyze the etiology and outcome of hydrops fetalis, we reviewed the records of 79 fetuses encountered at the National Taiwan University Hospital between January 1993 and October 1996. The mean +/- standard deviation gestational age at presentation was 24.9 +/- 6.3 weeks. One case was due to RhE incompatibility. Seventy-eight fetuses were diagnosed as having nonimmune hydrops fetalis; this was idiopathic in 20 fetuses. In the other 58, the causes and associated conditions were classified into eight groups: hematologic (25), cardiovascular (15), chromosomal (5), gastrointestinal (4), cystic hygroma (3), pulmonary (2), infection (2), and miscellaneous (3). One fetus with cystic hygroma also had a chromosomal abnormality (Turner's syndrome). The most common cause of nonimmune hydrops fetalis was homozygous alpha-thalassemia (31%). Twenty-nine fetuses were lost to follow-up after initial evaluation and 50 fetuses were delivered at our hospital. Of these, there were eight cases of antepartum death, 24 cases of intrapartum death, and 18 live births. Seventeen of the live-born infants were treated at our neonatal intensive care unit, of whom only seven survived.

Adult↗
PubMed1998

Early outcome of extremely low birth weight infants in Taiwan.

We retrospectively evaluated the outcome and the risk factors for mortality among extremely low birth weight (ELBW) infants born at National Taiwan University Hospital. The records of all live-born infants with body birth weight of less than 1,000 g from January 1, 1993, to December 31, 1996, were evaluated. Infants with major anomalies or whose parents refused resuscitation were excluded from the analysis. There were 81 ELBW infants (0.59%) among a total of 13,835 live births during the study period, and 73 cases were enrolled for study. The mean gestational age (GA) was 27.2 (range, 24-34) weeks. Sixty-six percent of the ELBW infants were born by cesarean delivery. Respiratory distress syndrome occurred in 64% of infants and exogenous surfactant therapy was given to 47%, while intermittent mandatory ventilation was given to 85%. Symptomatic patent ductus arteriosus occurred in 34% of infants, septicemia in 30%, chronic lung disease in 48%, grade III to IV intraventricular hemorrhage in 27%, stage III to V retinopathy of prematurity in 33%, and necrotizing enterocolitis in 8%. Neonatal survival was 74%, survival to discharge was 60%, and intact survival was 50%. The survival rate was 40% for infants with a birth body of weight less than or equal to 750 g, and 68% for those with a birth body weight of greater than 750 g. While survival was 27% for infants with a GA of less than 26 weeks, it was 75% for those with a GA of greater than or equal to 26 weeks. The survival rate improved year by year for those with a GA less than 28 weeks. Cox regression analysis of survival showed that Apgar score at 1 minute (p = 0.0063), pulmonary hypertension (p = 0.012), and severe intraventricular hemorrhage (p = 0.0031) were the most important factors associated with mortality. Though the outcome of ELBW infants in our institute seems poorer than in some more developed countries, it is improving. The prognosis for ELBW infants of 24 to 25 weeks' GA remains guarded under our present care.

Female↗
PubMed1998

Optimal timing of retina examinations for premature infants.

Developments in modern neonatal intensive care have resulted in increased survival of very premature infants. Along with this increase in survival, there has been a concomitant increase in the frequency of retinopathy of prematurity (ROP). We investigated the relationship between the severity and the time course of ROP as well as the optimal time for retinal examinations of premature infants of various birth weights and gestational ages. A total of 80 premature infants were enrolled for analysis. The mean postnatal age of infants at the time of diagnosis was 7.3 +/- 3.4 weeks for stage 1 retinopathy, 9.2 +/- 5.8 for stage 2 retinopathy, 9.5 +/- 3.8 for stage 3 retinopathy, 10.7 +/- 3.7 for threshold disease, and 11.7 +/- 3.2 for stage 4 retinopathy. The mean postconceptional age of infants at the time of diagnosis was 35 +/- 3 for stage 1 retinopathy, 36.4 +/- 3 for stage 2 retinopathy, 37.6 +/- 3.5 for stage 3 retinopathy, 38.4 +/- 3.5 for threshold disease, and 40 +/- 3.7 for stage 4 retinopathy. The age at the time of the initial detection of ROP was from the ninth to 10th week among infants weighing less than 1,000 g at birth and from the fifth to seventh week among those weighing 1,000 g or more at birth. However, the postconceptional age at the time of initial detection of ROP for the whole group was 36 weeks and was not influenced by birth weight or gestational age. Therefore, we suggest that postconceptional age, rather than postnatal age, should be used to decide the timing of retinal examinations for premature infants.

Female↗
PubMed1997

Lipoblastomatosis in a newborn: case report.

A male newborn had a well-circumscribed, solid mass on the right anterior chest wall at birth. Computed tomography disclosed an infiltrating soft-tissue mass over the right 6th to 9th ribs near the costochondral junction. Surgical excision was done at the age of 5 days. Pathologic examination showed lipoblastomatosis.

Humans↗
PubMed1997

Nephromegaly and elevated hepatocyte growth factor in children with biliary atresia.

Nephromegaly, a rarely mentioned but probably common situation, was studied in children with biliary atresia. We evaluated the length and the cross-sectional diameters of the kidney by ultrasound in 21 children with biliary atresia as well as in 50 healthy children. The ages ranged from 1 month to 10 years. Plasma hepatocyte growth factor (HGF) was measured in 18 children with biliary atresia and also in 18 age- and sex-matched normal controls. There was a significant nephromegaly (increase in the renal length and the kidney volume) in children with biliary atresia as compared with normal children (P < 0.001 by analysis of covariance). Plasma HGF levels were elevated in these patients (2.13 +/- 1.06 v 0.76 +/- 0.19 ng/mL in controls, P < 0.001) and had a positive correlation with the renal size after considering the effect of body height by multiple regression analysis (P = 0.0022 for renal length, and P < 0.001 for kidney volume). These results confirm the presence of large kidneys in biliary atresia and implicate the possible pathogenic role of HGF in such a condition. Nephromegaly in biliary atresia may provide a new in vivo model to study the mechanism of renal growth.

Biliary Atresia↗
PubMed1997

Mature teratoma arising from an intra-abdominal undescended testis presenting as a fetal abdominal mass.

Teratoma of the intra-abdominal testis is a rare finding in infants. We describe the case of a full-term newborn treated for a calcified abdominal mass which was observed unexpectedly on prenatal sonography. An undescended right testis was also noted. During laparotomy, a twisted retroperitoneal tumor was found just above the right deep inguinal ring. Histological analysis revealed a mature teratoma of the intra-abdominal right testis. The tumor was removed and there was no recurrence at follow-up 1 year later. A teratoma should be considered in cases of fetal abdominal mass, especially when the testes cannot be detected in the scrotum by the 8th month. Prenatal sonographic diagnosis might be possible.

Adult↗