Biomedical subjects

K L Cheung

Publications and source records attributed to K L Cheung.

At least 55 records · Page 3Linked to original sources

PubMed2000

Recurrent and novel mutations of GCDH gene in Chinese glutaric acidemia type I families.

Glutaric acidemia type I is caused by mutations of the glutaryl-CoA dehydrogenase (GCDH) gene resulting in loss of GCDH enzyme activity. Patients present with progressive dystonia and lesions in basal ganglia. Dietary treatment, when instituted from the early neonatal period, markedly reduces dystonia and morbidity. Early diagnosis and prenatal diagnosis will be facilitated by knowledge of locally prevalent GCDH mutations. Several common GCDH mutations have been found in different ethnic groups. GCDH mutations were studied in 5 Chinese glutaric acidemia type I families. We detected two novel recurrent mutations (A219T and IVS10-2A>C) which were found in two unrelated families. An asymptomatic carrier of IVS10-2A>C was also found on screening of 120 individuals. Other mutations were identified, including two other novel (R386G & IVS3+1G>A) and two known mutations (G178R & R355H). Fibroblasts from patients carrying the novel mutations were confirmed to be deficient for GCDH activity. This is the first report of GCDH mutations describing recurrent mutations in Chinese patients. The carrier rate of IVS10-2A>C may be particularly high in Chinese.

Alternative Splicing↗

PubMed2000

Central nervous system candidiasis in preterm infants: limited value of biochemical markers for diagnosis.

Two rare cases of isolated central nervous system (CNS) candidiasis in preterm infants have been diagnosed in a tertiary neonatal centre over the past 6 years. Despite the life-threatening nature of the disease, biochemical infection markers were not useful for the early identification of localized fungal infection. Because the infection was likely to have been blood borne, we postulated that the initial fungal load was probably low and that the organisms were rapidly eliminated from the circulation after a few had been deposited in the CNS. Hence, the absence of fungaemia or systemic involvement precluded the activation of cytokines and cellular markers. Clinicians should be aware of the limitation of biochemical infection markers so that diagnosis and treatment of fungal infection will not be delayed.

Biomarkers↗

PubMed2000

Tumour marker measurements in the diagnosis and monitoring of breast cancer.

Elevation of established blood tumour markers correlates with the stage of breast cancer. The major role of current blood markers is therefore in the diagnosis and monitoring of metastatic disease. A combination of markers is better than a single marker with the most widely adopted combination being CEA and one MUC1 mucin, commonly detected as either CA15.3 or CA27.29. Tumour marker measurement is now used as a complementary test in the diagnosis of symptomatic metastases. In the monitoring of therapeutic response to both endocrine and cytotoxic therapies in advanced disease, biochemical assessment using blood markers not only correlates with conventional UICC criteria but has a lot of advantages which make it a potentially superior way of assessment. In this regard, CA15.3, CEA and ESR are the best validated combination. Studies are ongoing to evaluate the use of sequential blood tumour marker measurements in the follow-up of patients after treatment for their primary breast cancer, in terms of both early detection and early therapeutic intervention. Further randomized studies are also required to ascertain that marker-directed therapy is superior to the current practice for metastatic disease. In line with clinical studies, intensive laboratory work is being carried out to optimize the use of blood markers in advanced disease as well as to exploit their use in screening and diagnosis of early primary breast cancer.

Biomarkers, Tumor↗

PubMed2000

Preoperative endocrine therapy for breast cancer.

The preoperative use of systemic therapy for primary breast cancer has the potential to downstage tumours. This would render suitable for breast conservation some tumours that were unsuitable at initial presentation, or would convert some inoperable locally advanced breast cancers into tumours that are operable. No survival benefit has been demonstrated for neoadjuvant chemotherapy compared with the same therapy given in an adjuvant setting. Preoperative endocrine therapy, in contrast to neoadjuvant chemotherapy, has fewer side effects and has the potential additional advantage that it can be continued throughout the perioperative period. Current data have shown that, in patients with an oestrogen receptor (ER)-positive tumour, a response approaching 70% could be reached in approximately 3 months using traditional endocrine manipulation such as tamoxifen. Randomised clinical trials are warranted to demonstrate the superiority of preoperative endocrine therapy over conventional adjuvant endocrine therapy, to define the optimum duration of therapy, and to identify the best endocrine agents. Both clinical and laboratory studies are also required to identify factors (in addition to ER) that would precisely predict the response and hence to select appropriate patients and to improve existing methods of monitoring response.

Antineoplastic Agents, Hormonal↗

PubMed2000

Primary carnitine deficiency in the Chinese.

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Carnitine↗

PubMed1999

Management of cyclical mastalgia in oriental women: pioneer experience of using gamolenic acid (Efamast) in Asia.

BACKGROUND: In most Western countries gamolenic acid is the first-line treatment for women with cyclical mastalgia. METHODS: A prospective study was carried out in the breast referral clinic of the Department of Surgery, University of Hong Kong to evaluate the treatment of cyclical mastalgia using gamolenic acid provided in evening primrose oil (Efamast, Scotia Pharmaceuticals Ltd, Scotia House, Stirling, Scotland) as a pioneer experience in Asia. In addition, the features of cyclical mastalgia in Oriental women were studied by conducting a survey using anonymous questionnaires. RESULTS: Sixty-six women with disturbing cyclical mastalgia seen by one breast surgeon were followed up with a breast pain diary. Thirty-four women had persistently disturbing mastalgia and were commenced on Efamast. Responses were measured at 3 and 6 months according to a standardized protocol. An overall useful response rate of 97% was observed at 6 months. Side-effects were found in 12% but all were insignificant. CONCLUSIONS: Efamast may be recommended as a first-line specific treatment for Oriental women with disturbing cyclical mastalgia.

Adolescent↗

PubMed1999

Early onset of hypernatraemic dehydration and fever in exclusively breast-fed infants.

Five cases of moderately severe hypernatraemic dehydration were identified within a 5-month period between two regional hospitals in Hong Kong. Unlike previous reported cases, these exclusively breast-fed infants presented with the unusual triad of fever, absence of overt signs of dehydration and within the first week of life. Three of the cases also had high serum bilirubin concentrations at presentation. The fever subsided quickly and the serum bilirubin concentration fell rapidly within a few hours of rehydration. All infants made an uneventful recovery without permanent neurological sequelae. Fever, presumably secondary to dehydration, is an useful early warning sign. These cases emphasize the importance of early and regular measurement of bodyweight in exclusively breast-fed infants so that prompt identification of affected cases may prevent potentially detrimental complications.

Age of Onset↗

PubMed1999

Management of primary breast cancer in Hong Kong -- can the guidelines be met?

AIMS: To assess the quality standards in the management of primary breast cancer in Hong Kong and as a result to give recommendations with regard to further improving the existing specialist service. METHODS: A prospective, continuous audit using quality standards laid down in the Guidelines for Surgeons in the Management of Symptomatic Breast Disease in the United Kingdom. RESULTS: Quality standards in surgical expertise, radiology and pathology service have reached the level required while there is still room for improvement in the diagnostic services. CONCLUSIONS: The establishment of an expeditious new referral system with combined surgical and radiological expertise should be pursued.

Adult↗

PubMed1999

Randomised controlled study of early use of inhaled corticosteroid in preterm infants with respiratory distress syndrome.

AIM: To investigate the therapeutic efficacy of inhaled fluticasone propionate, started on day 1 of age, on ventilated preterm infants with respiratory distress syndrome. METHODS: Starting within 24 hours of age, ventilated preterm infants (gestation < 32 weeks, birthweight < 1.5 kg) with respiratory distress syndrome were given a 14 day course (two puffs, 12 hourly) of either fluticasone propionate (250 microg/puff) (group 1, n=27) or placebo (group 2, n=26) with a metered dose inhaler-spacer device. Response to treatment was assessed by the rate of successful extubation by days 7 and 14 of age, changes in respiratory system mechanics, death, occurrence of chronic lung disease, and other neonatal complications. RESULTS: More infants in the treatment group were successfully extubated by 14 days of age than those in the placebo group (17/27 vs 8/26; p = 0.038). The treated infants also showed a more significant improvement in respiratory system compliance during the first 14 days of life. The two groups, however, did not differ significantly in their need for systemic steroids after day 14 of age, death, or the occurrence of chronic lung disease. The treatment was not associated with any increase in neonatal complications, including those attributable to steroid induced side effects. CONCLUSION: These results provide preliminary evidence that early treatment with inhaled corticosteroids may be beneficial to ventilated preterm infants with respiratory distress. Further study of its use in a large scale randomised trial is warranted.

Administration, Inhalation↗

PubMed1999

Severe congenital absence of skin in a preterm infant.

A severe case of aplasia cutis congenita in a preterm infant is described. Although major problems with thermoregulation and fluid balance were anticipated, these parameters were relatively easy to control once the patient was stabilized. Meticulous skin care and rapid formation of a membranous-like fibrous tissue layer covering the denuded areas probably played an important role in minimizing excessive fluid and heat loss. The prognosis in aplasia cutis congenita is determined by the underlying associated anomalies, the severity of skin lesions and, in our case, the maturity of the infant who died from complications of prematurity.

Ectodermal Dysplasia↗

PubMed1999

Classical galactosaemia in Chinese: A case report and review of disease incidence.

We report a case of galactose-1-phosphate uridyl transferase (GALT) deficiency in a full-term Chinese neonate, who presented with atypical biochemical features of hyperammonaemia in addition to the classical presenting features of jaundice and lethargy after feeding. Red cell GALT activity was virtually absent in the patient while 50% of normal activity was found in parents and a sibling. Mutation screening excluded both Q188R and N314D as the causative mutation in GALT gene, which suggested a possible genetic segregation among ethnic groups. Data from a Taiwan screening program suggested that the incidence of the disease was approximately 1 in 400 000 in the Chinese population which was a sixth of that in Caucasian populations.

Ammonia↗

PubMed1998

Racial variation in incidence of trisomy 21: survey of 57,742 Chinese deliveries.

The objective of this study was to establish whether the influence of advanced maternal age on the incidence of trisomy 21 in the local Chinese population is similar to that seen among European patients by comparing the observed number of trisomy 21 cases against the expected number which was calculated from age-specific Caucasian data and adjusted for intrauterine lethality and rate of amniocentesis. The obstetric and neonatal data of 57,742 pregnancies in ethnic Chinese were reviewed, of which 10.5% were from mothers age 35 or over. A total of 74 cases of trisomy 21 was detected (overall incidence of 1.28 per 1,000 deliveries). The expected number of trisomy 21 cases in mothers younger than 35 was 45.6, which was similar to the observed number of 43. Among mothers age 35 or above, the expected and observed numbers of cases were 38.52 and 31, respectively, again a difference not statistically significant. Therefore we conclude that there is no significant racial variation in the incidence of trisomy 21, both in the younger and older age groups, when comparing Chinese to Caucasian populations.

Asian People↗

PubMed1998

Hematologic malignancies with t(4;11)(q21;q23)--a cytogenetic, morphologic, immunophenotypic and clinical study of 183 cases. European 11q23 Workshop participants.

A total of 183 hematologic malignancies with t(4;11)(q21;q23), including five variant translocations, were collected by the Workshop. Clinical, morphologic and immunophenotypic features were compiled, and karyotypes with variant t(4;11) or secondary chromosomal aberrations were reviewed. All cases were acute leukemias (AL): 173 acute lymphoblastic leukemias (ALL), six acute myeloid leukemias (AML), three unclassifiable AL, and one biphenotypic AL. Ten patients had treatment-associated AL. Females were overrepresented (104 vs 79) and the age distribution was clearly nonrandom; 34% of the cases occurred in infants below the age of 12 months. The remaining AL were evenly distributed among the other age groups, with the oldest patient being 79 years old. An increased white blood cell count (WBC) was reported in more than 90% of the cases, with hyperleukocytosis (> or =100 x 10(9)/l) in 64%. Additional chromosomal changes were detected in 55 (30%) cases, most often gain of the X chromosome, i(7)(q10), and trisomy 8, with frequent breakpoints in 1p36, 1q21, 7q10, 11p15, 12p13, 17p11, and 17p10. All recurrent secondary changes resulted in genomic imbalances, in particular gains of 1q, 7q, 8, and X and losses of 7p and 17p. Event-free and overall survival (EFS and OS) could be ascertained in 170 and 171 patients, respectively. Kaplan-Meier estimates of EFS and OS showed no differences with regard to gender, WBC, or presence of secondary chromosomal abnormalities, and there was no increase of EFS or OS among the 55 cases that had undergone bone marrow transplantation. However, age had an important prognostic impact, with significantly (P < 0.0001) longer EFS and OS in children 2-9 years old than among infants and younger children, patients aged between 10 and 39 years and older adults.

Acute Disease↗

PubMed1998

Massive subdural haematoma: an unusual complication of septicaemia in preterm very low birthweight infants.

Non-traumatic massive subdural haematoma is a rare condition in newborn infants and is usually associated with hereditary coagulation disorders or congenital vascular malformation. Its occurrence in preterm very low birthweight infants secondary to systemic bacterial infection has not been reported. We describe two extremely preterm neonates who developed massive subdural haematoma as a result of gram-negative septicaemia and disseminated intravascular coagulation. Both infants suffered severe parenchymal cerebral injury and hydrocephalus. Clinicians should be aware of this unusual and catastrophic complication if a very low birthweight infant with severe sepsis and disseminated intravascular coagulation suddenly deteriorates despite successful treatment with antibiotics. Radiological imaging by cranial ultrasound or computed tomography scanning should be routinely considered in all such infants for the detection of intracranial bleeding.

Bacteremia↗

PubMed1998

Clinical prediction of post-extubation radiological changes of the chest in newborn infants.

OBJECTIVE: Whether a chest radiograph should be performed routinely in all infants after extubation, or selectively only in those with clinical deterioration, is a controversy in neonatal unit practice. This study tested the hypothesis that most cases of post-extubation radiological deterioration in the lungs could be detected by clinical assessment. METHODS: A chest radiograph was performed at 8 h post-extubation in 100 episodes of extubation in 85 newborn infants ventilated for a variety of lung diseases. Each infant was assessed at the same time by a neonatologist blinded to the radiological findings, to determine whether a chest radiograph would have been requested based on clinical judgement. The infants were continuously monitored for their respiratory and oxygenation status before and after extubation. RESULTS: Compared to the pre-extubation chest radiographs, 23 of the 100 post-extubation chest radiographs showed either deterioration of the pre-existing lung pathologies or appearance of significant new pathologies. The clinicians' assessment failed to detect most of the deterioration, with a sensitivity of only 21.7%. Systematic analysis of the infants' clinical parameters showed that the development of significant intercostal/subcostal retraction, and an increase in inspired oxygen concentration by > or = 7% after extubation, were the best predictors of post-extubation radiological deterioration (sensitivity 82.6%, specificity 62.3%, positive predictive value 39.6%, and negative predictive value 92.3%). Serial blood gas in contrast had little predictive value. CONCLUSION: We conclude that most cases of radiological deterioration of the lungs after extubation are clinically predictable, provided the correct clinical criteria are used.

Blood Gas Analysis↗

PubMed1998

Is homozygous alpha-thalassaemia a lethal condition in the 1990s?

Two cases of homozygous alpha-thalassaemia who received active treatment in accordance with parental wishes are reported. One infant survived and the other, although successfully weaned off mechanical respiratory support, unexpectedly developed portal vein thrombosis and died. Homozygous alpha-thalassaemia, a condition previously considered to be universally fatal, and an indication for therapeutic abortion, is now potentially curable with advances in diagnostic technology and treatment. However, active management of these cases raises serious ethical questions and has major financial implications on the health-care system. Invasive prenatal and intensive postnatal interventions should remain experimental and cannot be recommended as routine clinical practice until the questions of long-term neurodevelopmental outcome, and the morbidity and mortality associated with bone-marrow transplantation have been fully addressed. As a result of advances in information technology, more and more parents of affected foetuses are likely to request active treatment.

Fatal Outcome↗

PubMed1998

Risk factors for Enterobacter septicemia in a neonatal unit: case-control study.

Thirty cases of Enterobacter aerogenes or Enterobacter cloacae septicemia diagnosed over a 32-month period in a tertiary care neonatal unit were enrolled in a case-control study. Each case patient was matched with two controls (patients occupying the cots nearest the case patient when the latter developed septicemia). Of the 32 perinatal characteristics evaluated, 11 were identified by univariate analysis to be significantly associated with the infection. These included parents being residents of the Vietnamese refugee camps, respiratory distress syndrome, necrotizing enterocolitis, umbilical arterial catheterization, umbilical venous catheterization, bladder catheterization, mechanical ventilation, antibiotic treatment, peripheral venous catheterization, nasogastric intubation, and parenteral nutrition. Multivariate analysis, however, showed that preceding bladder catheterization and ongoing parenteral nutrition were the only independent risk factors for enterobacter septicemia. Strict aseptic technique in the preparation of parenteral nutrition fluid and avoidance of bladder catheterization are measures that may reduce the risk of enterobacter sepsis for newborns.

Bacteremia↗

PubMed1998

Randomised crossover trial of salbutamol aerosol delivered by metered dose inhaler, jet nebuliser, and ultrasonic nebuliser in chronic lung disease.

AIMS: To compare the efficacy of salbutamol delivered by metered dose inhaler (MDI), jet nebuliser, and ultrasonic nebuliser in ventilated infants with chronic lung disease. METHODS: Twenty preterm ventilated infants with chronic lung disease were enrolled in two studies. In study 1 (n = 10), each infant was given 200 micrograms of salbutamol at 4 hour intervals and in random sequence from a metered dose inhaler-spacer device, a jet nebuliser, and an ultrasonic nebuliser with a small medication cup. The infants were monitored for heart rate, transcutaneous pO2, pCO2, and oxygen saturation, respiratory system resistance and compliance before and after each treatment. Infants in study 2 (n = 10) were similarly studied except for the use of a different jet nebuliser. RESULTS: The mean (SEM) maximum percentage decreases in respiratory system resistance, observed at 30 minutes after aerosol delivery were study 1: MDI: 44.3 (4.3)%; jet: 32.3 (3.4)%; ultrasonic: 56.1 (3.2)%; study 2: MDI: 28.6 (1.0)%; jet: 16.9 (1.4)%; ultrasonic: 42.1 (1.6)%. During the first hour after treatment, a significantly faster heart rate and higher transcutaneous pO2 were associated with the use of the ultrasonic nebuliser or MDI than with the jet nebulisers in both studies. The use of the ultrasonic nebuliser but not the other devices also resulted in a lower transcutaneous pCO2 and improved respiratory system compliance in study 2. CONCLUSIONS: These findings suggest that among the devices tested, the delivery of salbutamol aerosol to the lower respiratory tract was greatest using the ultrasonic nebuliser, and least with the jet nebulisers.

Administration, Intranasal↗