Biomedical subjects

Pak C Ng

Publications and source records attributed to Pak C Ng.

At least 19 recordsLinked to original sources

PubMed2007

IP-10 is an early diagnostic marker for identification of late-onset bacterial infection in preterm infants.

Very low birth weight (VLBW) infants with suspected late-onset infection requiring sepsis screening were enrolled in a prospective study to evaluate the diagnostic utilities of a comprehensive panel of key chemokines and cytokines, both individually and in combination, to identify diagnostic markers for early recognition of bacterial sepsis and necrotizing enterocolitis (NEC). Plasma chemokines interleukin (IL)-8, interferon-gamma-inducible protein 10 (IP-10), monokine induced by interferon-gamma (MIG), monocyte chemoattractant protein 1 (MCP-1), growth-related oncogene-alpha (GRO-alpha), and regulated upon activation of normal T cell expressed and secreted (RANTES) and cytokines IL-1beta, IL-6, IL-10, IL-12p70, and tumor necrosis factor alpha (TNF-alpha) were measured at the onset of sepsis (0 h) and 24 h later. Of 155 suspected infection episodes, 44 were classified as infected. Concentrations of all studied inflammatory mediators (except IL-1beta and RANTES) were significantly higher in the infected than in the noninfected group at 0 h, but the levels decreased precipitously by 24 h. IP-10 with a plasma cutoff concentration > or = 1250 pg/mL could identify all septicemic and NEC cases and had the highest overall sensitivity (93%) and specificity (89%) at 0 h. We conclude that preterm infants have the ability to induce a robust chemokine and cytokine response during sepsis, and IP-10 is a sensitive early marker of infection.

Age of Onset↗

PubMed2006

Fetal methylmercury exposure as measured by cord blood mercury concentrations in a mother-infant cohort in Hong Kong.

This study was designed to examine newborn infants in Hong Kong prenatally exposed to levels of methylmercury considered to increase risk of neurotoxic effects and to examine subject characteristics that modify the degree of prenatal mercury exposure. Mercury concentrations in 1057 sets of maternal and cord blood samples and 96 randomly selected maternal hair samples were measured. Subject characteristics were measured or collected by questionnaire. Of the 1057 cord blood samples collected only 21.6% had mercury concentrations less than 29 nmol/L (5.8 micro g/L). Median maternal hair mercury concentration was 1.7 ppm. The geometric mean cord to maternal blood mercury ratio was 1.79 to 1. Increasing maternal fish consumption and maternal age were found to be associated with increased cord blood mercury concentrations. Marine fish consumption increased cord blood mercury concentrations more than freshwater fish (5.09%/kg vs 2.86%/kg). Female babies, maternal alcohol consumption and increasing maternal height were associated with decreased cord blood mercury concentrations. Pregnant women in Hong Kong consume large amounts of fish and as a result, most of their offspring have been prenatally exposed to moderately high levels of mercury. In this population, pregnant women should choose freshwater over marine fish and limit fish consumption.

Animals↗

PubMed2006

Early prediction of sepsis-induced disseminated intravascular coagulation with interleukin-10, interleukin-6, and RANTES in preterm infants.

BACKGROUND: The progression to disseminated intravascular coagulation (DIC) in infected very low birth weight (VLBW; <1500 g) infants is difficult to predict with precision at the onset of sepsis. We investigated the immunologic profiles of preterm infants with sepsis, using chemokine and cytokine measurements to predict the development of sepsis-induced DIC at the onset of infection. METHODS: We measured a panel of chemokines and cytokines at 0 and 24 h after clinical presentation in VLBW infants with suspected infection requiring full sepsis screening. The chemokines measured were interleukin (IL)-8, interferon-gamma-inducible protein-10 (IP-10), monokine induced by interferon-gamma, monocyte chemoattractant protein-1, and regulated upon activation normal T-cell expressed and secreted (RANTES), and the cytokines were IL-6, IL-10, and tumor necrosis factor-alpha. RESULTS: Of 195 episodes of suspected clinical sepsis investigated, 62 were culture-confirmed septicemia or necrotizing enterocolitis (28 of these infants developed DIC), 22 were culture-negative clinical infections, and 111 involved noninfected episodes. All studied inflammatory mediators except RANTES showed significantly greater up-regulation in culture-positive infected infants than in noninfected infants at 0 and 24 h, whereas RANTES showed significant down-regulation. The model that used plasma IL-10 (>208 ng/L), IL-6 (>168 ng/L), and RANTES (<3110 ng/L) at 0 h had sensitivity, specificity, and positive and negative predictive values of 100%, 97%, 85%, and 100%, respectively, for identifying infected patients who subsequently developed DIC. CONCLUSIONS: IL-10, IL-6, and RANTES measured at clinical presentation sensitively and accurately predicted the development of DIC in severely infected infants. This information could be vital for early and effective treatment of neonatal sepsis.

Chemokine CCL5↗

PubMed2006

Bronchodilator effect of salbutamol from two different spacer devices.

Our aim was to compare the bronchodilator effect of salbutamol delivered via a new holding chamber (Volumatic Soft, VS) with that of an established device (Volumatic, V) in asthmatic children. Children with stable asthma were recruited. They inhaled 100 microg, and 10 min later, 300 microg of salbutamol aerosol delivered via VS or V on day 1, and vice versa on day 2. Spirometry was measured at baseline, 10 min after 100 microg, and 15 min after 300 microg of salbutamol were given. The preference for either device was assessed by visual analogue score. Forty-four children with a median age of 9.2 years (interquartile range, 8.0-10.7) completed the study. There were significant improvements in forced expired volume in 1 sec (FEV1) with time throughout the study period for both V and VS (linear and quadratic trend P < 0.001). There was a statistically significant difference in postbronchodilator FEV1 between V and VS (P = 0.013). VS gave an overall greater change in FEV1 than V, by 1.8%. The preference scores for V and VS were 7.0 (IQR 5.0-8.0) and 9.0 (IQR 8.0-10.0) (p < 0.0005), respectively. In conclusion, comparable clinical efficacy was found for V and VS with respect to changes in FEV1 after salbutamol. Patients also showed a strong preference for the new device.

Adrenergic beta-Agonists↗

PubMed2006

Rapid control of norovirus gastroenteritis outbreak in an acute paediatric ward.

AIM: To provide a practical action plan for effective infection control of norovirus outbreak in acute paediatric wards. METHODS: We report the infection control measures that were implemented to terminate and to prevent nosocomial spread of norovirus gastroenteritis in an open-designed paediatric ward. RESULTS: Nine children, one visitor, and one medical student were affected in a norovirus gastroenteritis outbreak in an acute paediatric ward. Vomiting was the main presenting symptom. The outbreak was rapidly terminated three days after implementation of stringent infection control measures and there was no second wave of attack. These measures included strict contact precautions, prompt isolation and cohorting of symptomatic patients, vigorous environmental cleansing with concentrated disinfectant (hypochlorite solution 1000 ppm), meticulous handling of waste products, and efficient contact tracing of exposed patients, family members, and medical students. CONCLUSION: Prompt implementation of stringent infection control measures and contact tracing can rapidly terminate the norovirus outbreak and prevent a second wave of infection. Children with unexplained vomiting and those with contact history of gastroenteritis should be properly triaged, isolated, and investigated for possible infective causes, including norovirus-induced gastroenteritis.

Adolescent↗

PubMed2006

Ex utero intrapartum treatment (EXIT) for congenital giant ranula.

UNLABELLED: Congenital giant ranula causing life-threatening upper airway obstruction is a rare condition. A well-planned ex utero intrapartum treatment (EXIT) procedure for aspiration and decompression of the cystic lesion is simple, efficacious and effective in securing a patent airway before the fetus is completely delivered, and may prevent lifelong neurodevelopmental complications associated with perinatal asphyxia in such cases. CONCLUSION: EXIT could be a life-saving procedure for congenital giant ranula.

Adult↗

PubMed2006

Persistent Staphylococcus capitis septicemia in a preterm infant.

A preterm infant had persistent Staphylococcus capitis septicemia with 11 consecutive positive blood cultures over a period of 33 days. The clinical evidence suggested that the source of infection probably originated from the gastrointestinal tract. The combination of rifampin and linezolid treatment, together with prolonged stoppage of enteral feeding, successfully terminated the infection. Rifampin and linezolid should be considered as alternative antimicrobial agents when glycopeptides fail to eradicate Gram-positive pathogens from the host.

Acetamides↗

PubMed2006

Diagnostic markers for neonatal sepsis.

PURPOSE OF REVIEW: To review the current evidence on the use of infection markers for diagnostic evaluation of sepsis in neonates. RECENT FINDINGS: Recent research in immunology has led to the discovery of cell surface antigens, chemokines, cytokines and acute phase proteins that can potentially be used to 'rule in' or 'rule out' sepsis. The diagnostic utilities of key inflammatory mediators, including CD11b, CD64, interleukin-6 and interleukin-8, are promising and likely to become increasingly used as markers of infection for both diagnostic and prognostic purposes. SUMMARY: Serial measurements and use of combinations of markers have been reported to improve sensitivity and negative predictive value of these tests. Current markers are not infallible, however, and do not permit neonatologists to withhold antibiotics in sick infants with suspected infection. Thus, many have emerged as useful indicators for early discontinuation of unnecessary antimicrobial therapy. Some infection markers are also useful for identifying infants with severe infection and adverse prognosis. Advances in flow cytometry have allowed simultaneous measurement of key markers using only minimal blood volume. Judicious selection of a panel of markers with complementary properties could greatly increase the ability of neonatologists to diagnose infection and discern valuable prognostic information.

Acute-Phase Proteins↗

PubMed2006

A double-blind, randomized, controlled study of a "stress dose" of hydrocortisone for rescue treatment of refractory hypotension in preterm infants.

OBJECTIVE: To assess the effectiveness of a "stress dose" of hydrocortisone for rescue treatment of refractory hypotension and adrenocortical insufficiency of prematurity in very low birth weight (VLBW) infants. We hypothesized that significantly more VLBW infants who were receiving dopamine > or =10 microg/kg per min could wean off vasopressor support 72 hours after treatment with hydrocortisone. METHODS: A double-blind, randomized, controlled study was conducted in a university neonatal center. Forty-eight VLBW infants who had refractory hypotension and required dopamine > or =10 microg/kg per min were randomly assigned to receive a stress dose of hydrocortisone (1 mg/kg every 8 hours for 5 days; n = 24) or an equivalent volume of the placebo solution (isotonic saline; n = 24). RESULTS: The baseline clinical characteristics were similar between the groups. Serum cortisol concentrations were very low immediately before randomization in both groups of infants. Significantly more VLBW infants who were treated with hydrocortisone weaned off vasopressor support 72 hours after starting treatment. The use of volume expander, cumulative dose of dopamine, and dobutamine were significantly less in hydrocortisone-treated infants compared with control infants. In addition, the median duration of vasopressor treatment was halved in hydrocortisone-treated patients. Two versus 11 infants in the hydrocortisone and control groups required a second vasopressor for treatment of refractory hypotension. The trend (linear and quadratic) of the mean arterial blood pressure was also significantly and consistently higher in hydrocortisone-treated infants. CONCLUSIONS: A stress dose of hydrocortisone was effective in treating refractory hypotension in VLBW infants. Although routine and prophylactic use of systemic corticosteroids could not be recommended because of their potential adverse effects, this relatively low dose of hydrocortisone would probably be preferable to high-dose dexamethasone for treatment of refractory hypotension in emergency and life-threatening situations.

Blood Pressure↗

PubMed2005

Are your hands clean enough for point-of-care electrolyte analysis?

AIM: To investigate clinically significant analytical interference in point-of-care electrolyte analysis caused by contamination of blood specimens with hand disinfectant. METHODS: Six different hand hygiene products were added separately to heparinised blood samples in varying amounts as contaminant. The contaminated samples were analysed by three different blood gas and electrolyte analysers for assessing interference on measured whole blood sodium and potassium concentrations. RESULTS: There were significant analytical interferences caused by hand hygiene product contamination that varied depending on the combination of disinfectant and analyser. Small amounts of Microshield Antibacterial Hand Gel contamination caused large increases in measured sodium concentration. Such effect was much greater compared with the other five products tested, and started to occur at much lower levels of contamination. There was a trend towards lower sodium results in blood samples contaminated with Hexol Antiseptic Lotion (Hexol), the hand hygiene product that we used initially. Apart from AiE Hand Sanitizer, all the other hand disinfectants, especially Hexol, significantly elevated the measured potassium concentration, particularly when a direct ion-selective electrode method was used for measurement. CONCLUSIONS: Hand disinfectant products can significantly interfere with blood electrolyte analysis. Proper precautions must be taken against contamination since the resultant errors can adversely affect the clinical management of patients.

Anti-Bacterial Agents↗

PubMed2005

Clinical, virologic and immunologic profiles of a young infant with severe acute respiratory syndrome.

The clinical findings, plasma viral load, cytokines and chemokines of a 4-month-old infant with severe acute respiratory syndrome (SARS) were assessed at different phases of the disease. Ribavirin failed to inhibit SARS coronavirus (SARS-CoV) replication. One-step real time reverse transcription-polymerase chain reaction for plasma SARS-CoV RNA quantification was useful for early diagnosis and monitoring viremia.

Cytokines↗

PubMed2005

Ghrelin in preterm and term newborns: relation to anthropometry, leptin and insulin.

AIMS: This study aimed to investigate (i) the plasma ghrelin concentration at birth, (ii) the relationship of ghrelin with metabolic hormones, including leptin and insulin, and (iii) its association with anthropometric parameters, in appropriately grown preterm (23-36 weeks gestation) and term (37-42 weeks gestation) newborns. PATIENTS AND METHODS: Blood samples for hormonal assay were obtained from preterm (n = 81) and term newborns (n = 40) within the first 2 h of life and before milk feeding or energy intake. The relationship between plasma ghrelin and other metabolic hormones or anthropometric parameters was evaluated. RESULTS: Plasma ghrelin was detectable in all studied infants and the concentrations did not differ significantly between term and preterm infants [median (interquartile range): 1.21 (0.86-1.48) nmol/l vs. 1.04 (0.71-1.51) nmol/l, P = 0.52, respectively]. There was no overall significant correlation between plasma ghrelin and gestational age, anthropometric parameters and leptin or insulin. However, when term and preterm infants were analysed independently, plasma ghrelin was inversely correlated with birth weight (r = -0.31, P = 0.05) and body length (r = -0.33, P = 0.04) in the term infant group. CONCLUSIONS: Our findings suggested that plasma ghrelin concentrations were relatively constant at birth, between 23 and 42 weeks gestation, and ghrelin secretion did not appear to undergo gestational age-related variations. An inverse relationship between plasma ghrelin and anthropometric indices in term infants raised the possibility that ghrelin might adopt its physiological role in regulating growth and metabolism at a late stage of gestation (> or = 37 weeks gestation). This phenomenon could be beneficial to term newborns by stimulating their appetite and maintaining an adequate blood sugar level at the most critical period when nutrients from mothers are abruptly terminated after birth.

Birth Weight↗

PubMed2005

Congenital systemic Langerhans cell histiocytosis presenting as hydrops fetalis.

UNLABELLED: Congenital Langerhans cell histiocytosis (LCH) encompasses a wide spectrum of disease involvement and severity. Congenital "self-healing" cutaneous LCH represents one end of the spectrum, whereas the case we encountered represents the other extreme. A rare case of congenital LCH with severe multiorgan involvement presenting as hydrops fetalis is described in this report. Hydrops fetalis has not previously been associated with congenital LCH. The overall clinical features of this infant closely mimicked those of disseminated congenital infection, and he ran a fulminant and rapidly fatal course. CONCLUSION: A high index of suspicion is required to diagnose congenital LCH in the early neonatal period. Hydrops fetalis is an ominous sign and probably reflects severe systemic disease compromising the well-being of the fetus.

Fatal Outcome↗

PubMed2004

Neutrophil CD64 is a sensitive diagnostic marker for early-onset neonatal infection.

This prospective study aimed to evaluate the diagnostic utilities of neutrophil CD64 expression for the identification of early-onset clinical infection and pneumonia in term infants and to define the optimal cutoff value so that it may act as a reference with which future studies can be compared. Term newborns in whom infection was suspected when they were <72 h of age were recruited into the study. C-reactive protein (CRP) and expression of CD64 on neutrophils were measured at 0 h (at the time of sepsis evaluation) and 24 h. The sensitivity, specificity, positive predictive value, and negative predictive value (NPV) of CRP, CD64, and the combination of these two markers for predicting neonatal sepsis were determined. A total of 338 infants with suspected clinical sepsis were investigated, 115 of whom were found to be clinically infected. CRP and CD64 in infected infants were both significantly elevated at 0 and 24 h compared with noninfected infants (p < 0.001). The calculated optimal cutoff value for CD64 was 6136 antibody-phycoerythrin molecules bound/cell. CD64 has a very high sensitivity (96%) and NPV (97%) at 24 h. The addition of CRP only marginally enhanced the sensitivity and NPV (97 and 98%, respectively). In conclusion, neutrophil CD64 is a very sensitive diagnostic marker for the identification of early-onset clinical infection and pneumonia in term newborns. The results strongly suggest that measurement of neutrophil CD64 may allow neonatal clinicians to discontinue antibiotic treatment at 24 h in infants who are clinically stable and whose CD64 expressions are below the optimal cutoff level.

Age of Onset↗

PubMed2004

SARS in newborns and children.

The severe acute respiratory syndrome (SARS) is a highly contagious infection caused by a newly discovered strain of coronavirus (SARS-CoV). Infants born to pregnant women with SARS did not appear to acquire the infection through vertical transmission. Some newborn infants, however, developed severe intrauterine growth retardation and life-threatening gastrointestinal complications. It is now known that the clinical course and prognosis are different between paediatric and adult SARS patients. Young children (< 12 years), in general, run a less aggressive clinical course than do teenage and adult patients. Thus far, no fatalities have been reported in the paediatric age group (< or =18 years). This review describes the current understanding of the clinical manifestations, diagnostic tests, immunological profiles, patient management and outcomes of SARS-CoV infection in the paediatric population.

Adolescent↗

PubMed2004

Pregnancy and perinatal outcomes of women with severe acute respiratory syndrome.

OBJECTIVE: This study was undertaken to evaluate the pregnancy and perinatal outcomes of pregnant women with severe acute respiratory syndrome (SARS). STUDY DESIGN: All pregnant women (12) who presented with SARS in Hong Kong between February 1 and July 31, 2003, were included. The pregnancy and perinatal outcomes were collected. Evidence of perinatal transmission of virus was assessed with the SARS-associated coronavirus reverse-transcriptase polymerase chain reaction on cord blood, placenta tissue, and subsequent follow-up of the neonate on serology. RESULTS: Three deaths occurred among the 12 patients, giving a case fatality rate of 25%. Four of the 7 patients (57%) who presented in the first trimester had spontaneous miscarriage. Four of the 5 patients who presented after 24 weeks were delivered preterm. Two mothers recovered without delivery, but their ongoing pregnancies were complicated by intrauterine growth restriction. No newborn infant had clinical SARS and all investigations were negative for SARS. CONCLUSION: SARS during pregnancy is associated with high incidences of spontaneous miscarriage, preterm delivery, and intrauterine growth restriction. There is no evidence of perinatal SARS infection among infants born to these mothers.

Abortion, Spontaneous↗

PubMed2004

Inflammatory cytokine profile in children with severe acute respiratory syndrome.

OBJECTIVE: To study the inflammatory cytokine profile in children with severe acute respiratory syndrome (SARS) and to investigate whether monoclonal antibody to tumor necrosis factor-alpha (TNF-alpha) could be considered for treatment of these patients. METHODS: Plasma inflammatory cytokine concentrations (interleukin [IL]-1beta, IL-6, IL-8, IL-10, IL-12p70, and TNF-alpha) were monitored longitudinally on admission, immediately before corticosteroids, and 1 to 2 days and 7 to 10 days after the drug treatment in a cohort of pediatric patients (n = 8) with virologic confirmed SARS-associated coronavirus infection. None of the patients required mechanical ventilation or intensive care treatment. All children except 1 (patient 3) received corticosteroids. RESULTS: Plasma IL-1beta levels (excluding patient 3) were substantially elevated immediately before (range: 7-721 ng/L) and 7 to 10 days after (range: 7-664 ng/L) corticosteroid treatment. In contrast, the plasma concentrations of other key proinflammatory cytokines, including IL-6 and TNF-alpha, were not overtly increased in any of the patients throughout the course of illness. In addition, plasma IL-10 concentration was significantly lower 1 to 2 days and 7 to 10 days after corticosteroid treatment, compared with the immediate pretreatment level. Similarly, plasma IL-6 and IL-8 concentrations were significantly decreased 7 to 10 days after the drug treatment. CONCLUSIONS: Pediatric SARS patients have markedly elevated circulating IL-1beta levels, which suggests selective activation of the caspase-1-dependent pathway. Other key proinflammatory cytokines, IL-6 and TNF-alpha, showed only mildly elevated levels at the initial phase of the illness. The current evidence does not support the use of TNF-alpha monoclonal antibody in this group of children.

Adolescent↗

PubMed2003

Repeated courses of antenatal corticosteroids: is it justified?

The benefits of a single course of antenatal corticosteroids on neonatal outcomes are well established. There is, however, much controversy about how long this treatment should continue, and whether repeated courses should be administered if the women remain at risk for preterm delivery 7 days after the initial therapy. This review aims to discuss current evidence on the effectiveness and safety of repeated courses of antenatal corticosteroids.

Betamethasone↗