Effect of neonatal reticulocytosis on glucose 6-phosphate dehydrogenase (G6PD) activity and G6PD deficiency detection: a cross-sectional study.

BACKGROUND: Screening for G6PD deficiency in newborns can help prevent severe hemolysis, hyperbilirubinemia, and bilirubin encephalopathy, as recommended by the World Health Organization (WHO). It has been speculated that the presence of a high number of reticulocytes in newborns interferes with the diagnosis of G6PD deficiency since reticulocytes contain higher amounts of G6PD enzyme than mature erythrocytes. Therefore, the purposes of this study were to assess the effect of reticulocytosis in the determination of blood G6PD activity in Thai newborns by using a novel automated UV-based enzymatic assay and to validate the performance of this assay for the detection of G6PD deficiency in newborn samples. METHODS: The levels of reticulocytes and G6PD activity were measured in blood samples collected from 1,015 newborns. G6PD mutations were identified using TaqMan® SNP genotyping assay, PCR-restriction fragment length polymorphism (PCR-RFLP), and direct sequencing. The correlation between the levels of reticulocytes and G6PD activity was examined. The performance of the automated method was compared with that of the fluorescent spot test (FST) and the standard quantitative assay. RESULTS: The automated assay detected G6PD deficiency in 6.5% of the total newborn subjects compared to 5.3% and 6.1% by the FST and the standard method, respectively. The minor allele frequencies (MAFs) of G6PD ViangchanG871A, G6PD MahidolG487A, and G6PD UnionC1360T were 0.066, 0.005, and 0.005, respectively. The reticulocyte counts in newborns with G6PD deficiency were significantly higher than those in normal male newborns (p < 0.001). Compared with normal newborns after controlling for thalassemias and hemoglobinopathies, G6PD-deficient patients with the G6PD ViangchanG871A mutation exhibited elevated reticulocyte counts (5.82 ± 1.73%, p < 0.001). In a group of G6PD normal newborns, the percentage of reticulocytes was positively correlated with G6PD activity (r = 0.327, p < 0.001). However, there was no correlation between G6PD activity and the levels of reticulocytes in subjects with G6PD deficiency (r = -0.019, p = 0.881). The level of agreement in the detection of G6PD deficiency was 0.999, while the area under the receiver operating characteristic (AUC) curve demonstrated that the automated method had 98.4% sensitivity, 99.5% specificity, 92.4% positive predictive value (PPV), 99.9% negative predictive value (NPV), and 99.4% accuracy. CONCLUSIONS: We report that reticulocytosis does not have a statistically significant effect on the detection of G6PD deficiency in newborns by both qualitative and quantitative methods.

Age-Related Reference Intervals for Blood Amino Acids in Thai Pediatric Population Measured by Liquid Chromatography Tandem Mass Spectrometry.

BACKGROUND: Age, race, and analytic method influence levels of blood amino acids, of which reference intervals are required for the diagnosis and management of inherited metabolic disorders. OBJECTIVES: To establish age-specific reference intervals for blood amino acids in Thai pediatric population measured by liquid chromatography tandem mass spectrometry (LC-MS/MS). METHODS: A cross-sectional study of 277 healthy children from birth to 12 years was conducted. Anthropometric, clinical, and dietary information were recorded. Dried blood spots on a filtered paper were used for measurement by derivatized LC-MS/MS. Factors that might affect amino acids such as fasting time and dietary intake were analyzed using quantile regression analysis. RESULTS: Levels of thirteen blood amino acids were reported as median and interval from 2.5th-97.5th percentiles. Compared with those of Caucasian, most blood amino acid levels of Thai children were higher. Compared with a previous study using HPLC in Thai children, many amino acid levels are different. Glycine, alanine, leucine/isoleucine, and glutamic acid sharply decreased after birth. Citrulline, arginine, and methionine stayed low from birth throughout childhood, whereas phenylalanine was at middle level and slightly increased during preadolescence. CONCLUSION: Reference intervals of age-specific blood amino acids using LC-MS/MS were established in the Thai pediatric population. They diverge from previous studies, substantiating the recommendation that, for the optimal clinical practice, age-specific reference intervals of amino acids should be designated for the particular population and analysis method.

Short-term outcome of PDA ligation in the preterm infants at King Chulalongkorn Memorial Hospital, Thailand.

BACKGROUND: Failure of the ductus arteriosus to close after medical treatment is usually associated with many severe cardio-respiratory morbidities. Therefore, surgical ligation of symptomatic PDA is indicated in preterm newborn infants who do not respond or have contraindication of medical treatment. OBJECTIVE: To report the short-term outcomes of PDA ligation in preterm infants at a tertiary care hospital in Thailand. MATERIAL AND METHOD: Medical records of 42 preterm infants who underwent surgical ligation of PDA at King Chulalongkorn Memorial Hospital were reviewed All of the infants had symptomatic PDA that failed to respond to medical treatment or had a contraindication to indomethacin or ibuprofen. Surgical ligation of PDA was performed under general anesthesia. Morbidity and mortality occurring during hospitalization were reported. RESULTS: There were 42 preterm infants in the present study. All of them had large PDA with intractable congestive heart failure. Mean + SD of birth weight and gestational age were 1206 +/- 567 grams and 28.7 +/- 3.6 weeks respectively. Mean +/- SD of the infants' weight and age at the time of surgery were 1089 +/- 549 grams and 17.5 +/- 12 days respectively. Data on the size of PDA was available on 21 preterm infants. Their ductus diameter (Mean +/- SD) was 3.1 +/- 1.1 mm. All infants were successfully extubated after PDA ligation. Twelve events of complications occurred in 11 infants (26.7%). All of the complications were of mild degree and resolved within a few days except one infant with left phrenic nerve injury that needed surgical plication of the diaphragm. Two infants died at 37 and 160 days after surgery and the latter infant developed IVH grade IV on the 15th day postoperatively. These complications were probably not related to PDA ligation. CONCLUSION: PDA ligation was performed successfully on 42 preterm infants who had medical failure or had contraindication to medical treatment. Cardio-respiratory illnesses improved significantly after ligation. Two infant mortalities were not related to the procedure. Overall complication of surgery was 26.7% and resolved without sequelae.

Nephrocalcinosis in very low birth weight infants: a single center experience.

OBJECTIVES: To determine the incidence and risk factors of nephrocalcinosis in very low birth weight infants. MATERIAL AND METHOD: Medical records of inborn infants with gestational age less than 32 weeks or birth weight less than 1,250 grams were collected and analyzed. All infants were born at King Chulalongkorn Memorial Hospital in the year 2003. At least one renal ultrasonographic scan was performed on every infant as a routine screening before discharge. Data on family history of renal stone, gestational age, birthweight, infant's illness,fluid intake during the first 6 weeks of life, duration of respiratory support, medications, serum calcium, phosphate and alkaline phosphatase level, duration of parenteral nutrition, length of hospitalization, ultrasonographic findings and related renal morbidity were collected and compared between the groups of infants with and without nephrocalcinosis. RESULTS: Thirty six infants were included in the present study. Fourteen had abnormal ultrasound scans compatible with nephrocalcinosis giving an overall incidence of 38.9%. Factors associated with nephrocalcinosis included severity of respiratory illness, PDA, oxygen dependency, furosemide therapy, and fluid restriction. Urinary tract infection was the renal morbidity found in 3 infants (21.4%). Nephrocalcinosis was resolved in one out of 7 infants who had repeated renal ultrasound scan at about 2 months after the first scan. CONCLUSION: Very low birth weight, preterm infants have a risk of developing nephrocalcinosis especially those with severe respiratory illness and prolonged use of furosemide. Infants at risk should be screened with renal ultrasonography prior to discharge from the hospital.

A review of laparoscopy for non-obstetric-related surgery during pregnancy.

PURPOSE: Similar to the general population, parturients (and their fetuses) could benefit from the reduced manipulation associated with laparoscopy. The purpose of this article is to review the current state of knowledge (both clinical and experimental) with respect to the fetal effects of maternal laparoscopy for non-obstetric-related surgery during pregnancy. METHODS: Human and experimental animal results are examined, and we present preliminary data from our own laboratory. CONCLUSIONS: Future experiments are proposed to further develop and refine standards of care for general surgeons and obstetricians who are presented with gravid females in abdominal distress.

Antibody response to hepatitis B immunization in infants born to HIV-infected mothers.

OBJECTIVES: To determine the antibody response of hepatitis B immunization begun at birth in HIV-1 exposed infants. DESIGN: Prospective, clinical trial. SITE: King Chulalongkorn Memorial Hospital, Bangkok, Thailand. MATERIAL AND METHOD: Seventy six infants born to HIV-1 seropositive mothers, who were not hepatitis B carriers, received three 10 microgram doses of recombinant DNA hepatitis B vaccine (Engerix B, Smith Kline, Belgium) in a 0, 1 and 6 month schedule. The first dose was given at birth. Serum hepatitis B surface antibody (Anti -HBs) was measured at age 3, 9 and 12 months. Anti-HBs levels were determined by enzyme-linked immunoassay using the commercial kits (AUSAB EIA diagnostic kits, Abbott Laboratories, Chicago, USA) Antibody titer > or = 10 mIU/ml was defined as seroconversion. HIV infection was diagnosed by a positive test of HIV antibody at age > or = 18 months and/or by positive test of HIV polymerase chain reaction at age > or = 3 months. RESULTS: There were 14 HIV-1 infected (group 1) and 62 HIV-1 non infected (group 2) infants enrolled in this study. Anti-HBs titers of group 1 infants were significantly lower than those of groups 2 infants at both 3 and 6 months after the 3rd dose of vaccine, (Mann Whitney U test, p=0.019 and 0.001 respectively). Ten infants in group 1 and 57 infants in group 2 had anti-HBs titer > or = 10 mIU/ml. Their peak antibody titers were also noted at both 3 and 6 months after the 3rd dose of vaccine. Seroconversion rates were 71.4 per cent and 91.9 per cent in group 1 and 2 infants respectively, (p<0.05). Among the infants who had blood tests performed at age 12 months or 6 months after the 3rd dose of vaccine, anti-HBs titers declined in approximately 50 per cent of both groups of infants. There was a significantly higher percentage of seroconverters in group 1 who lost their protective titers than those in group 2, (p<0.001). CONCLUSION: The results in this study suggested that HIV-1 infected infants have poor antibody response to hepatitis B immunization and the protection was less durable. A fourth dose of vaccine at 6 months after the 3rd dose may be necessary.