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Biomedical subjects

K L Kwok

Publications and source records attributed to K L Kwok.

At least 19 recordsLinked to original sources
PubMed2006

Obstructive sleep apnoea in children with Down syndrome.

INTRODUCTION: Children with Down syndrome (DS) are prone to develop obstructive sleep apnoea (OSA) for a combination of reasons, including small upper airway, midfacial hypoplasia, micrognathia and muscular hypotonia. The objective of this study was to compare the prevalence of OSA in DS children, with or without snoring, with snoring children matched for gender, age and weight for height. METHODS: DS children were prospectively recruited from the Hong Kong Down Syndrome Association. All recruited DS children underwent a sleep polysomnography (PSG) in our sleep laboratory. The same number of patients without DS who underwent sleep PSG in the same period were enrolled as controls after they were matched for gender, age and weight for height. OSA was defined as apnoea-hypopnoea index (AHI) greater than 1.5. RESULTS: 22 DS patients and 22 snoring controls completed the overnight PSG. The mean age of DS children and snoring controls was 10.82 +/- 5.93 and 10.27 +/- 5.68 years, respectively. The prevalence of OSA was 59 percent in DS children and 32 percent in snoring controls. Median and interquartile range (IQR) of AHI of DS children (median 1.80, IQR is 0.40 to 7.10) were significantly higher than those of controls (median 0.50, IQR is 0.00 to 2.03, p-value equals 0.041). Out of 13 DS children with OSA, eight of them (61.5 percent) had no habitual snoring. CONCLUSION: 59 percent of DS children in the current series were found to have OSA and they were more likely to develop OSA than controls. Nearly 40 percent of DS children with OSA did not have habitual snoring.

Adolescent↗
PubMed2006

Application of artificial neural networks to establish a predictive mortality risk model in children admitted to a paediatric intensive care unit.

INTRODUCTION: Paediatric risk of mortality and paediatric index of mortality (PIM) are the commonly-used mortality prediction models (MPM) in children admitted to paediatric intensive care unit (PICU). The current study was undertaken to develop a better MPM using artificial neural network, a domain of artificial intelligence. METHODS: The purpose of this retrospective case series was to compare an artificial neural network (ANN) model and PIM with the observed mortality in a cohort of patients admitted to a five-bed PICU in a Hong Kong non-teaching general hospital. The patients were under the age of 17 years and admitted to our PICU from April 2001 to December 2004. Data were collected from each patient admitted to our PICU. All data were randomly allocated to either the training or validation set. The data from the training set were used to construct a series of ANN models. The data from the validation set were used to validate the ANN and PIM models. The accuracy of ANN models and PIM was assessed by area under the receiver operator characteristics (ROC) curve and calibration. RESULTS: All data were randomly allocated to either the training (n=274) or validation set (n=273). Three ANN models were developed using the data from the training set, namely ANN8 (trained with variables required for PIM), ANN9 (trained with variables required for PIM and pre-ICU intubation) and ANN23 (trained with variables required for ANN9 and 14 principal ICU diagnoses). Three ANN models and PIM were used to predict mortality in the validation set. We found that PIM and ANN9 had a high ROC curve (PIM: 0.808, 95 percent confidence interval 0.552 to 1.000, ANN9: 0.957, 95 percent confidence interval 0.915 to 1.000), whereas ANN8 and ANN23 gave a suboptimal area under the ROC curve. ANN8 required only five variables for the calculation of risk, compared with eight for PIM. CONCLUSION: The current study demonstrated the process of predictive mortality risk model development using ANN. Further multicentre studies are required to produce a representative ANN-based mortality prediction model for use in different PICUs.

Adolescent↗
PubMed2005

Assessment of the Pediatric Index of Mortality (PIM) and the Pediatric Risk of Mortality (PRISM) III score for prediction of mortality in a paediatric intensive care unit in Hong Kong.

OBJECTIVE: To compare two models (The Pediatric Risk of Mortality III score and Pediatric Index of Mortality) for prediction of mortality in a paediatric intensive care unit in Hong Kong. DESIGN: Prospective case series. SETTING: A five-bed paediatric intensive care unit in a general hospital in Hong Kong. PATIENTS: All patients consecutively admitted to the unit between April 2001 and March 2003. MAIN OUTCOME MEASURES: Scores for both models compared with observed mortality. RESULTS: A total of 303 patients were admitted to the paediatric intensive care unit during the study period. The median age was 2 years, with an interquartile range of 7 months to 7 years. The male to female ratio was 169:134 (55.8%:44.2%). The median length of hospital stay was 3 days. The overall predicted number of deaths using The Pediatric Risk of Mortality III score was 10.2 patients whereas that by Pediatric Index of Mortality was 13.2 patients. The observed mortality was eight patients. The area under the receiver operating characteristics curve for the two models was 0.910 and 0.912, respectively. CONCLUSION: The predicted mortality using both prediction models correlated well with the observed mortality.

Child↗
PubMed2005

Kawasaki disease in Hong Kong, 1994 to 2000.

OBJECTIVE: To describe the epidemiology, clinical characteristics, and management of Kawasaki disease in children in Hong Kong. DESIGN: Retrospective survey of medical records from July 1994 to June 1997, and prospective data collection from July 1997 to June 2000. SETTING: Hospitals with a paediatric unit in Hong Kong. PATIENTS: Patients diagnosed with Kawasaki disease between July 1994 and June 2000 in public hospitals in Hong Kong. MAIN OUTCOME MEASURES: Incidence of Kawasaki disease and coronary artery aneurysm rates. RESULTS: A total of 696 cases of Kawasaki disease were reported. There were 435 (62.5%) boys and 261 (37.5%) girls giving a male to female ratio of 1.7:1. The age ranged from 1 month to 15 years 5 months with a median of 1.7 years. Infants (<1 year) constituted the largest group of patients (223, 32.0%) and overall, 638 (91.7%) were younger than 5 years. Skin rash, conjunctivitis, and oral signs were among the principal clinical features present in over 80% of cases. Prominent cervical lymph nodes larger than 1.5 cm were less commonly found (24%). Coronary artery aneurysms or ectasia were present in 15.7% (109/696), 8.5% (59/696), and 5.0% (35/696) of patients at 2, 4, and 8 weeks, respectively. The incidence of Kawasaki disease per 100,000 children under 5 years was significantly higher in the prospective study period than in the retrospective period (39 vs 26, P<0.001). CONCLUSION: The incidence of Kawasaki disease is high in Hong Kong and is 39 per 100,000 children below 5 years of age. The coronary artery aneurysm prevalence is 5%. Intravenous gamma-globulin and high-dose aspirin is the mainstay of treatment.

Adolescent↗
PubMed2004

Embryotrophic factor-3 from human oviductal cells enhances proliferation, suppresses apoptosis and stimulates the expression of the beta1 subunit of sodium-potassium ATPase in mouse embryos.

BACKGROUND: Embrytrophic factor-3 (ETF-3) from human oviductal cells enhanced the development of mouse preimplantation embryos. This report studied the embryotrophic mechanisms of the molecule. METHODS AND RESULTS: Mouse embryos were incubated with ETF-3 for 24 h at different stages of development. ETF-3 treatment between 96 and 120 h post-HCG increased the cell count of blastocysts, whilst treatment between 72 and 96 h post-HCG enhanced the expansion and hatching of the blastocysts. ETF-3 increased the cell number of the embryos by suppressing apoptosis and increasing proliferation as determined by TUNEL and bromodeoxyuridine uptake assays, respectively. Real-time quantitative PCR showed that the in vivo developed and ETF-3-treated blastocysts had a significantly higher mRNA copy number of Na/K-ATPase-beta1, but not of hepsin, than that of blastocysts cultured in medium alone. The former gene was associated with cavitation of blastocysts while the latter was related to hatching of blastocyst. The beneficial effect of ETF-3 on blastocyst hatching was also seen when ETF-3-supplemented commercially available sequential culture medium for human embryo culture was used to culture mouse embryos. CONCLUSIONS: ETF-3 improves embryo development by enhancing proliferation, suppressing apoptosis and stimulating expression of genes related to blastocyst cavitation. Supplementating human embryo culture medium with ETF-3 may improve the success rate in clinical assisted reproduction.

Animals↗
PubMed2004

Obstructive sleep apnoea syndrome and obesity in children.

OBJECTIVE: To review data on children who have both obesity and obstructive sleep apnoea syndrome. DATA SOURCE: Pubmed and MEDLINE (Ovid) literature search using the following key words: obstructive sleep apnea syndrome, obesity, and children. STUDY SELECTION: Literature and data on obesity-associated obstructive sleep apnoea syndrome in children. DATA EXTRACTION: Review of relevant information and data. DATA SYNTHESIS: Different definitions of obesity and obstructive sleep apnoea syndrome in children were used in different studies, which made it difficult to compare results from different studies conducted in different countries. Nonetheless, obstructive sleep apnoea syndrome was found to be moderately prevalent among obese children-namely, 13% to 36%. The severity of obstructive sleep apnoea syndrome was positively related to the degree of obesity. Blood pressure was found to be elevated in obese children with obstructive sleep apnoea syndrome. Weight reduction is an effective treatment. CONCLUSION: Children with obesity and obstructive sleep apnoea syndrome face a double challenge. A holistic approach to management requires a clear understanding of how both problems interact.

Child↗
PubMed2004

Hepatotoxicity and persistent renal insufficiency after repeated supratherapeutic paracetamol ingestion in a Chinese boy.

Paracetamol has always been regarded as a useful and safe drug. The risk of toxicity with repeated supratherapeutic paracetamol is an underrecognised condition. We report on a 12-month-old boy who presented with hepatotoxicity, disseminated intravascular coagulation and persistent renal insufficiency 4 days after repeated ingestion of a supratherapeutic dosage of paracetamol. To the best of our knowledge, this is the first reported case of paediatric chronic paracetamol poisoning among the Chinese population. In addition, persistent renal insufficiency has not been a previously reported feature of chronic paracetamol poisoning. We propose that renal damage is the result of the synergistic effect of hypoperfusion and paracetamol overdose.

Acetaminophen↗
PubMed2003

Embryotrophic factor-3 from human oviductal cells affects the messenger RNA expression of mouse blastocyst.

Our previous results showed that embryotrophic factor-3 (ETF-3) from human oviductal cells increased the size and hatching rate of mouse blastocysts in vitro. The present study investigated the production of ETF-3 by an immortalized human oviductal cell line (OE-E6/E7) and the effects of ETF-3 on the mRNA expression of mouse embryos. The ETF-3 was purified from primary oviductal cell conditioned media using sequential liquid chromatographic systems, and antiserum against ETF-3 was raised. The ETF-3-supplemented Chatot-Ziomek-Bavister medium was used to culture Day 1 MF1 x BALB/c mouse embryos for 4 days. The ETF-3 treatment significantly enhanced the mouse embryo blastulation and hatching rate. The antiserum, at concentrations of 0.03-3%, abolished the embryotrophic effect of ETF-3. Positive ETF-3 immunoreactivity was detected in the primary oviductal cells, OE-E6/E7, and blastocysts derived from ETF-3 treatment. Vero cells (African Green Monkey kidney cell line), fibroblasts, and embryos cultured in control medium did not possess ETF-3 immunoreactivity. The mRNA expression patterns of the treated embryos were studied at the blastocyst stage by mRNA differential display reverse transcription-polymerase chain reaction (DDRT-PCR). The DDRT-PCR showed that some of the mRNAs were differentially expressed after ETF-3 treatment. Twelve of the differentially expressed mRNAs that had high homology with cDNA sequences in the GenBank were selected for further characterization. The differential expression of seven of these mRNAs (ezrin, heat shock 70-kDa protein, cytochrome c oxidase subunit VIIa-L precursor, proteinase-activated receptor 2, eukaryotic translation initiation factor 2beta, cullin 1, and proliferating cell nuclear antigen) was confirmed by semiquantitative RT-PCR. In conclusion, immortalized oviductal cells produce ETF-3, which influences mRNA expression of mouse blastocyst.

Animals↗
PubMed2002

Habitual snoring and sleep bruxism in a paediatric outpatient population in Hong Kong.

OBJECTIVE: To determine the prevalence of habitual snoring and sleep bruxism in children attending the out-patient clinics of a paediatric department. METHODOLOGY: A cross-sectional survey of parents was conducted with questionnaire administered by paediatric nurses. Parents were recruited when they brought their children to the out-patient clinics. Sex and age were recorded. Presence and absence of habitual snoring and sleep bruxism were noted. Types of diseases that brought the children to the out-patient clinics were also noted. RESULTS: Twenty-nine of the 200 recruited children were noted to have habitual snoring (14.5%, 95% C.I. 10%-20%). The mean age of these habitual snorers was 6.2 +/- 3.1 years. For habitual snorers, male to female ratio was 1.4 to 1. Sixteen of these 28 children accepted a sleep polysomnographic examination. Eleven children were found to have snoring during the night of study. Two were found to have obstructive sleep apnoea syndrome. Sleep bruxism was found in 17 children (8.5%, 95% C.I.5%-13%). Sleep bruxism was closely related to habitual snoring as 16 out of the 17 children with sleep bruxism were also habitual snorers (p < 0.0001). CONCLUSION: Habitual snoring and sleep bruxism were commonly found in children attending paediatric clinics. Paediatricians should be aware of these problems and be prepared to deal with them. Habitual snoring and sleep bruxism were closely related. Further studies into this relationship is needed.

Ambulatory Care Facilities↗
PubMed2001

Severe chronic neutropenia in Chinese children in Hong Kong.

OBJECTIVE: Severe chronic neutropenia (SCN) is a rare and heterogeneous disorder in children. The epidemiology, clinical features and outcomes of SCN in Chinese children were reviewed. METHODOLOGY: A retrospective analysis of case records was undertaken for 18 children with SCN managed during a 12-year period in a university teaching hospital in Hong Kong. RESULTS: The median (range) age of the patients at initial presentation was 6.5 months (4 days-19 months). The initial and lowest median absolute neutrophil counts (ANC) were 0.29 x 109 /L and 0.06 x 109 /L, respectively. Patients with congenital SCN had significantly fewer neutrophils in peripheral blood at diagnosis. Only five subjects received granulocyte colony-stimulating factor (G-CSF) treatment. All children were free from serious infection on follow up for 51 months. Only one child suffered from long-term infection-related morbidity. One patient with chronic neutropenia was subsequently shown to have common variable immunodeficiency. CONCLUSIONS: Most children with SCN in our series had favourable clinical outcomes. Our results support the recommendation that G-CSF should be used only in those with recurrent or severe infections.

China↗
PubMed2001

Nocturnal enuresis and obstructive sleep apnoea in two children.

Nocturnal enuresis was a symptom of childhood obstructive sleep apnoea, OSAS. We reported two children with secondary nocturnal enuresis which disappeared after tonsillectomy and adenoidectomy for proven OSAS. Pathogenesis of secondary nocturnal enuresis in OSAS was discussed.

Adenoidectomy↗
PubMed2000

Suppression subtractive hybridization identifies genes expressed in oviduct during mouse preimplantation period.

Fertilization and development of mouse embryos occur in the ampullae of oviduct. Various growth factors and embryotrophic factors produced by the oviductal cells have been demonstrated to enhance embryo development in vitro. As a step towards understanding the genetic changes of mouse oviduct during mouse embryos preimplantation period, we adopted suppression subtractive hybridization (SSH) to establish four subtracted cDNA libraries to identify (1) oviduct-expressing genes, and (2) genes that may support embryo development in vivo. Using this method, we isolated 82, 88, 99, and 109 clones from four mouse libraries prepared from 0 (day 0), 24 (day 1), 48 (day 2), and 72 h (day 3) post-human chorionic gonadotropin (hCG) treated mice. Reverse dot-blot analysis confirmed that 25 (day 0), 24 (day 1), 40 (day 2), and 29 (day 3) clones were highly expressed in mouse oviduct when compared to other tissues. DNA sequence analysis identified genes encoding mouse oviduct-specific glycoprotein (MOGP), actin-binding protein 280, and several viral genes. Northern analysis confirmed that the genes were mainly expressed in oviduct, with some viral genes also expressed in uterus. About 9% of these oviduct expressing clones (11/118) were novel. We further demonstrated that one of the novel clones ODEG0-17 was expressed in the oviduct during early embryo preimplantation period and rarely in other tissues by RT-PCR. Our results show that SSH is a powerful method applicable to identifying tissue-specific transcripts on fertilization and development.

Animals↗
PubMed2000

Unilateral right-sided internal jugular phlebectasia in asthmatic children.

The most common cause of a neck mass that increases in size on straining is laryngocele. Internal jugular phlebectasia, which is of unknown cause, may present similarly. We present three cases of internal jugular phlebectasia, all of whom were asthmatic children. This association of asthma and internal jugular phlebectasia has not been reported previously.

Asthma↗
PubMed1982

Coronary disease progression and its effect on left ventricular function.

To determine the effect of coronary disease progression on left ventricular function, 47 patients who had two cardiac catheterizations at a mean interval of 25 months (range three to 92 months) without intervening surgery were studied. Of these, 35 patients had coronary disease and 12 patients had normal or near normal coronary arteries. Coronary disease progression was seen more often in patients with initial coronary disease than in those without significant disease (66 percent vs 25 percent, p less than 0.02). Left ventricular ejection fraction decreased in patients with coronary disease progression (0.63 +/- 0.03 to 0.51 +/- 0.04, p less than 0.01) but was unchanged in patients without progressive disease (0.58 +/- 0.04 to 0.57 +/- 0.93, p = NS). Interval myocardial infarction was the major cause of deteriorating left ventricular function. The rate or degree of coronary disease progression did not predictably change global left ventricular function, and progressive disease in individual vessels did not predictably alter regional left ventricular function. The presence or development of collateral vessels did not significantly alter ventricular performance.

Angiography↗