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Biomedical subjects

N Y Boo

Publications and source records attributed to N Y Boo.

At least 55 records · Page 3Linked to original sources
PubMed1997

An evaluation of the usefulness of a culture system for the detection of Ureaplasma urealyticum in the endotracheal aspirates of neonates.

In this study, we evaluated the usefulness of a culture system used in our laboratory for the detection of Ureaplasma urealyticum in the endotracheal aspirates of neonates. Ureaplasmal broth was used to enhance the growth of U. urealyticum followed by observation of colonies on A7 agar. Of the 68 samples of endotracheal aspirates tested, 60 gave positive indication of urease activity by the broth. However, only 14 yielded U. urealyticum colonies on A7 agar medium. Polymerase chain reaction detected U. urealyticum in 21 samples. The use of Ureaplasmal broth was therefore not specific for the diagnosis of U. urealyticum. We suggest that subculture onto agar medium or PCR is essential for definite identification of U. urealyticum.

Bacteriological Techniques↗
PubMed1997

Prevalence and antibiotic susceptibility of Ureaplasma urealyticum in Malaysian neonates with respiratory distress.

Ureaplasma urealyticum was isolated from the endotracheal aspirates of 39 (21.4%) of 182 neonates with respiratory distress requiring ventilatory support. Mycoplasma hominis was isolated from one (0.5%) neonate. Bacterial cultures were negative in 123 (67.6%) neonates. Antibiotic susceptibility test carried out on ten isolates of U. urealyticum showed that all the organisms were sensitive to erythromycin but resistant to lincomycin and sulfamethoxazole trimethoprim. All, except one, U. urealyticum were sensitive to tetracycline and minocycline. Two isolates were resistant to ciprofloxacin. This study showed that U.urealyticum was a common organism isolated from the endotracheal aspirates of neonates with respiratory distress.

Anti-Bacterial Agents↗
PubMed1997

Neurodevelopmental outcome of Malaysian very low birth weight infants: predictive value of cranial ultrasound appearances.

The aim of the study was to determine the predictive value of cranial ultrasound scans done in the neonatal period for neurodevelopmental outcome of the Malaysian very low birthweight (VLBW, < 1500 grams) infants assessed at 12 months of corrected age. Of the 101 infants studied, 68 (67.3%) were neurodevelopmentally normal at one year of age, 18 (17.8%) had major and 15 (14.9%) had minor neurodevelopmental impairment. Neurodevelopmental outcome was normal in 66/88 (75.0%) infants who did not have severe intraventricular haemorrhage (IVH) or periventricular intraparenchymal echo densities (PVE) in the first week of life, and in 57/73 (78.1%) with uncomplicated scans at discharge. In contrast, 11/13 (84.6%) with parenchymal echo densities or severe intraventricular bleed in the early neonatal period and 17/28 (60.7%) with complicated scans at discharge had adverse sequelae. There was a significant association between lesions seen on cranial ultrasound in the neonatal period and subsequent neurodevelopmental impairment. Late neonatal ultrasound scans appear to be a better predictor of short-term neurodevelopmental outcome than early scans.

Child Development↗
PubMed1996

Comparison of morbidities in very low birthweight and normal birthweight infants during the first year of life in a developing country.

OBJECTIVE: To compare the morbidities in the very low birthweight (VLBW; < 1500 g) and normal birthweight (NBW; > or = 2500 g) Malaysian infants during the first year of life. METHODOLOGY: Prospective observational cohort study of consecutive surviving VLBW infants and randomly sampled NBW infants born in the Kuala Lumpur Maternity Hospital between 1 December 1989 and 31 December 1992. Infants were followed up regularly during the first year of life, after correction for prematurity. RESULTS: Compared with NBW infants (n = 106), VLBW infants (n = 127) had significantly higher risk of failure to thrive (odds ratio [OR] = 8.0, 95% confidence intervals [CI]: 1.1 to 354.3), wheezing (OR = 3.7, 95% CI: 1.6 to 9.3), rehospitalization (OR = 2.3, 95% CI: 1.1 to 5.0), cerebral palsy (OR = 8.6, 95% CI: 2.0 to 77.6), neurosensory hearing loss (OR = 12.0, 95% CI: 1.7 to 513.6) and visual loss (7.9 vs 0%, P = 0.002). The mean mental developmental index (MDI) and mean psychomotor developmental index (PDI) at 1 year of age were significantly lower among VLBW infants (MDI 99 [SD = 28], PDI 89 [SD = 25]) than NBW infants (MDI 106 [SD = 18], PDI 101 [SD = 18]) (95% CI for difference between means being MDI: -14.1 to -1.7; and PDI: -17.6 to -6.0). Logistic regression analysis showed that among VLBW infants: (i) male sex, Malay ethnicity and bronchopulmonary dysplasia were significant risk factors associated with wheezing; (ii) longer duration of oxygen therapy during the neonatal period, seizures after the post-neonatal period and wheezing were significant risk factors associated with rehospitalization; and (iii) longer duration of oxygen therapy during the neonatal period was a significant risk factor associated with adverse neurodevelopmental outcome during the first year of life. CONCLUSIONS: Compared with NBW infants, VLBW Malaysian infants had significantly higher risks of physical and neuro-developmental morbidities.

Case-Control Studies↗
PubMed1996

Surfactant protein A and stable microbubble formation in tracheal aspirates.

This study aimed to determine the role of surfactant protein A (SP-A) in the formation of stable microbubble in tracheal aspirates. Our results showed that as the concentration of anti SP-A antibodies added to tracheal aspirate specimens increased, the number of stable microbubble formed in the specimen decreased. The correlation between stable microbubble counts and the SP-A levels in the tracheal aspirates was good, r = 0.85, p < 0.05. This study suggests that SP-A plays an important role in stable microbubble formation. Measurement of small stable microbubbles is thus a useful bedside test for predicting the SP-A activity in the tracheal aspirates and in indirect measurement of lung maturity.

Animals↗
PubMed1995

Duration of oxygen therapy and exchange transfusion as risk factors associated with retinopathy of prematurity in very low birthweight infants.

One hundred and thirteen consecutive infants with a very low birthweight of less than 1500 g were followed prospectively for 6 months to determine the incidence of retinopathy of prematurity (ROP) and associated risk factors. Of this group, 36 (31.9%) infants developed ROP (13 infants had stage 1 ROP, nine had stage 2, six had stage 3, six had stage 4, and two had cicatricial stage ROP). Stepwise logistic regression analysis of various potential risk factors (birthweight, gestation, duration of oxygen therapy, duration of ventilation, highest documented PaO2 and exchange transfusion) showed that only two risk factors were significantly associated with the development of ROP. These risk factors were: the duration of oxygen therapy (p = 0.0005) and exchange transfusion during the neonatal period (odds ratio 5.754, 95% confidence interval 1.002 to 32.997, p = 0.049). The equation of the regression model is: log (odds of developing ROP) = -0.8395 + 0.1447 (OXY)- 0.8750 (ET), where OXY is the duration of oxygen therapy in days, ET = -1 when there was a history of exchange transfusion, and ET = 1 when there was no history of exchange transfusion.

Exchange Transfusion, Whole Blood↗
PubMed1995

Enzyme activity of glucose-6-phosphate dehydrogenase-deficient Malaysian neonates during the first 10 days of life.

OBJECTIVE: The objective of this study was to determine the degree of severity of enzyme deficiency in glucose-6-phosphate dehydrogenase (G6PD)-deficient Malaysian neonates as part of an effort to identify risk factors associated with severe hyperbilirubinaemia in G6PD-deficient infants. METHODOLOGY: During this study, enzyme activity was measured in 53/59 (89.8%) hospital-diagnosed G6PD-deficient neonates (34 Malays, 12 Chinese, and seven other ethnic groups) born consecutively in the Kuala Lumpur Maternity Hospital. All neonates, except one, were males. RESULTS: The mean level of enzyme activity of the 52 males G6PD-deficient neonates (0.47 iu/g Hb, 95% confidence intervals: 0.37, 0.57) was less than 10% of that of normal Malaysian male neonates. The enzyme activity of the only female G6PD-deficient infant, at 1.11 iu/g Hb, was 12.5% of the mean G6PD enzyme activity of normal females. CONCLUSION: Our results showed that G6PD deficiency in Malaysian neonates predominantly affects males and is usually severe.

Analysis of Variance↗
PubMed1995

Cytogenetic study of Malaysian neonates with congenital abnormalities in Maternity Hospital Kuala Lumpur.

During the period 1 January 1990-31 December 1990, 68 neonates with congenital abnormalities were successfully analysed for chromosome abnormalities in order to determine the contribution of chromosome aberrations to the aetiology of congenital abnormalities. The neonates were karyotyped employing the G-banding technique. Twenty-nine babies showed abnormal chromosome karyotypes. Twenty-six were observed to have classic trisomy syndromes; ie. trisomy 21 (32.3%), trisomy 18 (3.0%), and trisomy 13 (3.0%). The mean maternal age of the mothers with babies having normal karyotype was lower than the mean maternal age of the mothers having babies with abnormal karyotypes. From this study the incidence of congenital abnormalities due to chromosomal abnormalities is found to be 1:838 livebirths. Frequency of newborns having abnormal chromosomes is 0.14% for Malays, 0.12% for Chinese and 0.06% for Indians.

Chromosome Aberrations↗
PubMed1995

Bacteraemic infections in a neonatal intensive care unit--a nine-month survey.

A survey was conducted to determine the rate, outcome, and culture and sensitivity patterns of bacteraemic infections in a large Neonatal Intensive Care Unit (NICU). Over a nine-month period, 136 episodes of infection occurred in 132 (6.9%) out of 1926 admissions. Early onset infection accounted for 35 episodes (25.7%) and was associated with a higher mortality rate compared to late onset infection (45.7% vs 23.8%, p < 0.02). Very low birthweight (VLBW) infants had significantly higher rates of infection (19.4% vs 5.3%, p < 0.001) and mortality (45.2% vs 23.3%, p < 0.02) compared to bigger babies. Gram negative bacilli accounted for 25 early and 90 late isolates while gram positive organisms accounted for 10 early and 16 late isolates. The two main organisms (Acinetobacter and Klebsiella) showed a 69.0 to 85.3% resistance to aminoglycosides and 3rd generation cephalosporins. Ten of 13 isolates of Staphylococcus epidermidis and 3 of 4 Staphylococcus aureus were methicillin resistant. Multiply resistant infections were a major problem in this NICU and efforts to eradicate them needed to be intensified.

Bacterial Infections↗
PubMed1995

Nucleotide 1376 G-->T mutation in G6PD-deficient Chinese in Malaysia.

G6PD deficiency is the most common human enzymopathy and affects 200 million people worldwide. To date more than 400 biochemical variants and at least 60 different point mutations in the G6PD locus have been discovered. In Malaysia the overall incidence of G6PD deficiency among males is 3.1%, being more prevalent among the Chinese and Malays and less common among the Indians. As part of our initial effort to characterise G6PD deficiency in the Malaysian population, we investigated 18 G6PD deficient Chinese male neonates for the G6PD mutation G-->T at nt 1376, a common mutation seen among the Chinese in Taiwan and mainland China. The mutation was detected by a PCR-based technique using primers that artificially create a site for restriction enzyme Xho I. We found 61% (11 out of 18) of the Chinese G6PD deficient male neonates positive for this mutation. Study of enzyme electrophoretic mobility in 7 of the cases positive for this mutation revealed three different patterns of mobility. 107% (5 out of 7), 103% (1 out of 7) and 100% (1 out of 7). This study shows that mutation G-->T at nt 1376 is a common allele causing G6PD deficiency in Malaysians of Chinese origin. The finding of different patterns of electrophoretic mobility among the 7 cases positive for 1376 G-->T mutation supports the notion that diverse biochemical variants may share the same mutation.

Asian People↗
PubMed1995

An in-house ELISA method for measuring surfactant protein A.

An in-house enzyme-linked immunoabsorbant assay (ELISA) for SP-A was successfully developed using in-house polyclonal anti SP-A and a commercial polyclonal anti-rabbit immunoglobulin horseradish peroxidase conjugate system. The standard curve, generated by using 50 ng of SP-A to coat the plate and 1:500 dilution of polyclonal anti SP-A as a primary antibody, was linear for concentrations of SP-A ranging from 4 micrograms/l to 4000 micrograms/l and reproducible. Results of recovery study of SP-A from a known sample of tracheal aspirate ranged from 94%-114%. Intra- and inter-assay coefficients of variations were 2.7% and 5.6% respectively for a known sample of tracheal aspirate. Interference study showed that tracheal aspirate did not interfere with the assay. The assay developed was intended to be used for SP-A measurement in tracheal aspirates obtained from neonates with and without respiratory distress syndrome.

Enzyme-Linked Immunosorbent Assay↗
PubMed1995

Isolation of human surfactant protein A from amniotic fluid.

Surfactant protein A (SP-A) is one of the four known surfactant-associated proteins found in human lungs. It plays a major role in determining regulation of surfactant uptake and resecretion. Qualitative and quantitative deficiencies of SP-A may contribute to neonatal respiratory distress syndrome. The measurement of its level in amniotic fluid or neonatal tracheal aspirate may be useful in the assessment of replacement therapy using natural or synthetic surfactants. In order to develop an in-house immunoassay to detect the level of SP-A, we used a discontinuous sucrose density gradient to isolate SP-A from amniotic fluid. Polyacrylamide gel electrophoresis was carried out on the isolates with low molecular weight markers. We successfully isolated SP-A from 12 out of 31 samples of amniotic fluid. The isolates were found to be relatively pure and have a molecular weight of about 35 kD. The isolated SP-A were used as immunogens to raise antibodies in rabbits for the immunoassay.

Amniotic Fluid↗
PubMed1994

Risk factors associated with hearing loss in term neonates with hyperbilirubinaemia.

A study of 128 jaundiced term neonates showed that 28 (22 per cent) had hearing loss based on brain stem-evoked response. There was no significant difference in the percentage of neonates with hearing loss between those with peak serum bilirubin levels of less than 340 mumol/l (16 per cent) and those with hyperbilirubinaemia > 339 mumol/l (33 per cent) (P = 0.11). Logistic regression analysis showed that severe jaundice which required exchange transfusion and earlier age of onset of hyperbilirubinaemia were statistically significant risk factors associated with hearing loss (P = 0.038 and P = 0.012, respectively).

Age Factors↗
PubMed1994

Six year trend of neonatal septicaemia in a large Malaysian maternity hospital.

A study carried out in the Maternity Hospital, Kuala Lumpur over a 6 year period from 1986 to 1991, showed that the annual rates of septicaemia ranged from 5.2 to 10.2/100 admissions. Septicaemia accounted for between 11.0 to 30.4% of all neonatal deaths. The case fatality ratios ranged from 23.0 to 52.2%, being highest in 1989 when basic facilities were compromised. Low birthweight neonates accounted for 55.5% of those with septicaemia. The most common causative organisms were Staphylococcus epidermidis and Staphylococcus aureus in 1986 and 1987, but from 1988 Klebsiella species became the most common. More than 50% of neonatal septicaemia occurred after the age of 2 days. The results of the study demonstrated the dynamism of infection control: when control measures introduced earlier were not sustained, outbreaks of nosocomial infection recurred or worsened.

Cross Infection↗
PubMed1994

Glucose-6-phosphate dehydrogenase enzyme activity of normal term Malaysian neonates of different ethnic origins.

The cord blood glucose-6-phosphate dehydrogenase (G6PD) enzyme activity of 262 normal term Malaysian neonates (92 Malays, 96 Chinese and 74 Indians) was quantitatively determined by the World Health Organisation method. Analysis of variance for the levels of G6PD enzyme activity by ethnic origin and sex showed that there was a significant difference between mean levels of enzyme activity in the three ethnic groups (P = 0.03) but no difference between the sexes (P = 0.36). Multiple range analysis showed that Malays had significantly higher mean levels of G6PD enzyme activity than those of Chinese (P = 0.01). There was no significant difference between the mean levels of G6PD enzyme activity of Chinese and Indians (P = 0.52), nor was there any difference between those of Malays and Indians (P = 0.08). The difference in levels of G6PD enzyme activity among the different ethnic groups could be due to the existence of different G6PD variants.

Analysis of Variance↗
PubMed1994

Absence of rotavirus in the neonatal special care nursery of a Malaysian maternity hospital.

The pattern of rotavirus infection in babies of the neonatal special care nursery (SCN) of the Kuala Lumpur Maternity Hospital was studied. The presence of rotavirus in the neonates' stools was ascertained using the method of polyacrylamide gel electrophoresis and silver staining. No rotavirus was detected in the 511 stools and rectal swabs collected from the 164 neonates over a 8-week period. Thus the babies admitted to the SCN from the labour rooms and the postnatal wards of the hospital were unlikely to be carriers of rotavirus or infected by rotavirus during their stay. It was concluded that rotavirus was not endemic in the nursery or the postnatal wards of this maternity hospital.

Feces↗
PubMed1994

Intrauterine growth of liveborn Malaysian infants between gestation of 28 to 42 weeks.

A cross-sectional study was carried out on 8,478 consecutive normal singleton Malaysian neonates born in the Maternity Hospital, Kuala Lumpur. The objectives were to compare the mean birth-weights, crown-heel lengths and head circumferences of Malay, Chinese and Indian infants at gestation age from 28 to 42 weeks, and to construct the Malaysian growth charts. Above the gestation age of 34 weeks, the birthweights were significantly influenced by maternal gravida status (p < 0.03), ethnic origin (p < 0.001) and/or sex of the neonates (p < 0.026). Above this gestation age, neonates of multigravida mothers were significantly heavier than those of primigravida mothers; Indians were significantly lighter than Malays and Chinese; and males were significantly heavier than females. The head circumferences and body lengths of neonates were significantly influenced by ethnic origin, sex and/or maternal gravida status at gestation above 35 and 36 weeks respectively (p < 0.05). It was most likely due to the small sample size which explained our inability to detect statistically significant difference in all measurements (birthweight, length and head circumference) by sex, ethnicity and maternal gravida status at gestation below 35 weeks. Based on the measurements obtained in this study, percentile charts for the Malaysian population were constructed and made available for the first time. These charts will be useful for the assessment of Malaysian neonates during the perinatal period.

Birth Weight↗