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Biomedical subjects

C H Ko

Publications and source records attributed to C H Ko.

At least 19 recordsLinked to original sources
PubMed2006

Risk factors of long bone fracture in non-ambulatory cerebral palsy children.

OBJECTIVES: To identify the risk factors for long bone fractures in non-ambulatory cerebral palsy children. DESIGN. Case-control study. SETTING: A residential rehabilitation centre in Hong Kong. PATIENTS: The fracture group comprised 19 (13 male, 6 female) cerebral palsy children aged 4 years 5 months to 18 years 11 months (mean, 10 years; standard deviation, 3 years 9 months), who had their first long bone fracture during the period June 1992 to May 2001 inclusive. The control group was composed of 90 (46 male, 44 female) concomitant cerebral palsy residents aged 6 years 1 month to 16 years 11 months (mean, 9 years 11 months; standard deviation, 2 years 4 months) with no history of long bone fracture. MAIN OUTCOME MEASURES: Presence of features considered relevant to the risk of fracture, namely: anthropometry, feeding practice, orthopaedic surgery and duration of postoperative immobilisation, extremity contracture, anti-epileptic medications, and general health status in the 12 months prior to the fracture. RESULTS: Of the 19 fracture episodes, 18 occurred in the femur and one in the tibia/fibula. Multivariate analysis revealed that weight for age Z scores (adjusted odds ratio=0.41, 95% confidence interval, 0.19-0.86) and recent postoperative immobilisation (weeks) [adjusted odds ratio=1.35, 95% confidence interval, 0.97-1.89] were independent predictors for fracture occurrence. CONCLUSION: Early intervention targeting these risk factors may reduce the fracture risk in non-ambulatory cerebral palsy children.

Adolescent↗
PubMed2004

Randomised control trial of tongue acupuncture versus sham acupuncture in improving functional outcome in cerebral palsy.

BACKGROUND: Traditional Chinese medicine (TCM) has been used historically in the treatment of cerebral palsy (CP). We investigated the efficacy of acupuncture in improving the motor function of children with CP. METHODS: A randomised control trial was conducted to assess the effect of tongue acupuncture (TAC) in 33 CP children. The subjects were randomised to treatment (n = 22) with TAC or control (n = 11). Clinical outcome was evaluated using the gross motor function measure (GMFM) and the pediatric evaluation of disability inventory (PEDI). RESULTS: The increase in mean GMFM score was significantly greater in the treatment than in the control group (p = 0.042). CONCLUSION: An improvement in motor function of CP subjects is seen following a short course of acupuncture.

Acupuncture Therapy↗
PubMed2004

Dentatorubral-pallidoluysian atrophy in two Chinese families in Hong Kong.

We report on two Hong Kong Chinese families with dentatorubral-pallidoluysian atrophy. Two children in one family presented with progressive myoclonic epilepsy syndrome, and two children in the other family presented with ataxochoreo-athetoid symptoms. Early-onset childhood dentatorubral-pallidoluysian atrophy involved mental retardation, whereas myoclonic epilepsy was the predominant complaint in later-onset childhood version of the disease. Aspiration pneumonia was common in the late stage of disease. Dentatorubral-pallidoluysian atrophy is an autosomal dominant condition attributed to CAG trinucleotide repeats in the dentatorubral-pallidoluysian atrophy gene. The four children in this series had 63 to 79 CAG repeats. The expanded allele was inherited from the father in both families. One father had 54 CAG repeats and was asymptomatic; the other had 66 repeats and had an unsteady gait. Because the radiological, electroencephalographic, and electrophysiological findings were non-specific, we suggest that DRPLA gene testing should be performed in any child presenting with a variable combination of myoclonic epilepsy, mental retardation or developmental regression, and ataxochoreo-athetosis.

Adolescent↗
PubMed2004

Correlation of colposcopic anogenital findings and overall assessment of child sexual abuse: prospective study.

OBJECTIVE: To examine the relationship between colposcopic anogenital findings and overall assessment of sexual abuse. DESIGN: Prospective study. SETTING: Regional hospital, Hong Kong. PATIENTS: Seventy-seven children (mean age, 6.5 years; range, 6 months-16 years) referred consecutively for sexual abuse evaluation between July 1999 and June 2002 were included. MAIN OUTCOME MEASURES: Colposcopic anogenital findings (categorised as normal, non-specific, concerning for abuse, or clearly abnormal) were correlated with the overall assessment of likelihood of abuse (classified as no evidence of abuse, possible abuse, probable abuse, or definite abuse). The sensitivity and specificity of clearly abnormal findings in detecting definite abuse were computed, and the diagnostic impact of colposcopy findings were expressed as likelihood ratios. RESULTS: Anogenital findings were normal in 45% of patients, non-specific in 29%, concerning for abuse in 13%, and clearly abnormal in 13%. Seven of the 16 confirmed cases of sexual abuse had normal or non-specific findings. Overall assessment showed that 46% of all patients had no evidence of abuse, 20% had cases of possible abuse, 13% had cases of probable abuse, and 21% had cases of definite abuse. The sensitivity and specificity of abnormal anogenital findings in detecting definite abuse were 56.3% and 98.4%, respectively. Colposcopy showed a fair correlation with the overall assessment of abuse (weighted kappa, 0.245). The diagnostic impact of normal, non-specific, concerning, and clearly abnormal findings in terms of likelihood ratios were 0.23, 1.12, 0.00, and 34.30, respectively. CONCLUSIONS: Anogenital findings are often normal or non-specific in sexual abuse. In general, colposcopy examination findings do not directly reflect the final diagnosis. A category-4 finding on colposcopy is very helpful in confirming definite abuse, whereas other findings do not rule out the diagnosis.

Adolescent↗
PubMed2002

Paediatric stroke: case series.

Five cases of paediatric stroke are reported. Two patients presented with idiopathic stroke, another following vertebral artery dissection, one secondary to Moyamoya disease, and one patient with the syndrome of mitochondrial encephalopathy, lactic acidosis, and stroke-like episodes. The presentation, investigation, and management of paediatric stroke are discussed.

Adolescent↗
PubMed2001

Atypical presentation of dopa-responsive dystonia: generalized hypotonia and proximal weakness.

Dopa-responsive dystonia (DRD) is an autosomal dominant disorder typically presenting as dystonia with diurnal variability. Described is an 8-year-old boy who had had waddling gait, generalized hypotonia, and proximal weakness since early childhood. He responded well to low-dose L-dopa. He had a point mutation of the GTP cyclohydrolase I gene. The patient's father and sister had the same mutation but did not have proximal weakness. GTP cyclohydrolase I deficiency can present with hypotonia and weakness.

Carbidopa↗
PubMed2001

Circadian phase-shifted rats show normal acquisition but impaired long-term retention of place information in the water task.

It is thought that circadian rhythms may influence learning and memory processes. However, research supporting this view does not dissociate a mnemonic impairment from other performance deficits. Furthermore, published reports do not specify the type of memory system influenced by the circadian system. The present study assessed the effects of phase shifting on acquisition and expression of place navigation in the water maze, a task sensitive to hippocampal dysfunction. The results showed that phase-shifting circadian rhythms in rats impaired the expression of place information on a retention test but not initial acquisition or encoding of place information. These results suggest that disruption of circadian rhythms may impair consolidation of previously encoded hippocampal place information.

Animals↗
PubMed2001

Ictal (99m)Tc ECD SPECT in paroxysmal kinesigenic choreoathetosis.

Paroxysmal kinesigenic choreoathetosis is a rare neurologic disorder characterized by sudden attacks of brief involuntary dyskinetic movement that are precipitated by voluntary movement. A 14-year-old male who presented with frequent brief attacks of hemidystonia triggered by sudden movement is reported. Investigations, including video electroencephalogram and magnetic resonance imaging of brain, were normal. There was excellent and sustained response to carbamazepine. Ictal single-photon emission computed tomography using (99m)Tc ethyl cysteinate dimer revealed increased perfusion of the contralateral basal ganglia, which is associated with onset of choreoathetosis attacks. Our findings provide evidence that hyperactivity of the basal ganglia is associated with the dyskinetic attacks in paroxysmal kinesigenic choreoathetosis.

Adolescent↗
PubMed2001

Topiramate-induced metabolic acidosis: report of two cases.

Two children who presented with symptomatic metabolic acidosis after being put on topiramate (TPM) are reported. The first patient was an 11-year-old male with refractory complex partial epilepsy who was put on TPM for 13 months. He developed hyperventilation 1 week after increasing the dose to 300 mg/day. Arterial blood gas revealed hyperchloraemic metabolic acidosis with partial respiratory compensation: pH 7.36, PCO2 27.2 mmHg, bicarbonate 14.9 mEq/L, base excess -8.9 mmol/L. Hyperventilation and acidosis resolved after administration of sodium bicarbonate and reduction of the dose of TPM. The second patient was a female who developed increasing irritability at age 16 months and 21 months, each time associated with introduction of TPM and resolved promptly upon withdrawal of the drug. Venous blood gas taken during the second episode revealed pH 7.34, PCO2 37.4 mmHg, bicarbonate 20.4 mEq/L, base excess -4.2 mmol/L. The predominant mechanism of TPM-induced hyperventilation involves inhibition of carbonic anhydrase at the proximal renal tubule, resulting in impaired proximal bicarbonate reabsorption. The occurrence of hyperpnoea or mental status change in any patient who is on TPM should prompt an urgent blood gas sampling, with correction of the acid-base disturbances accordingly.

Acidosis↗
PubMed2001

De novo mutation in the mitochondrial tRNALeu(UUR) gene (A3243G) with rapid segregation resulting in MELAS in the offspring.

A 14-year-old Chinese boy with a normal perinatal and early developmental history presented at 5 years of age with migraine, intractable epilepsy, ataxia, supraventricular tachycardia, paralytic ileus and progressive mental deterioration. Computerized tomography revealed multiple cerebral infarcts in the parieto-occipital region without basal ganglial calcification. Magnetic resonance imaging showed increased signal intensity in T2 weighted images in the same regions. A cerebral digital subtraction angiogram was normal. Venous lactate, pyruvate, lactate to pyruvate ratio and cerebrospinal fluid lactate were elevated. Muscle biopsy did not reveal any ragged red fibres; dinucleotide-tetrazolium reductase activity was normal. Mitochondrial DNA analysis detected an adenine to guanine mutation at nucleotide position 3243 of tRNALeu(UUR). All four tissues analysed demonstrated heteroplasmy: leucocyte 56%, hair follicle 70%; buccal cell 64%; muscle 54%. The mother and brother of the proband, both asymptomatic, were also found to have a heteroplasmic A3243G mutation in the leucocytes, hair follicle and buccal cells. Other members of the maternal lineage, including the maternal grandmother, did not have the mutation. This report describes a patient with mitochondrial encephalopathy, lactic acidosis, stroke-like episodes, who presented with multisystem involvement. The absence of ragged red fibres in muscle biopsy did not preclude the diagnosis. Mutational analysis of mitochondrial DNA conveniently confirmed the diagnosis of the disorder. A de novo mutation is demonstrated in this family.

Adolescent↗
PubMed2001

Valproic acid and thrombocytopenia: cross-sectional study.

OBJECTIVE: To investigate the relationship between platelet count and serum valproic acid level, age, duration of valproic acid therapy, and polytherapy, and to determine the clinical significance of thrombocytopenia associated with high-dosage valproic acid therapy. DESIGN: Cross-sectional study. SETTING: Residential unit for neurologically impaired children and paediatric out-patient clinic, Hong Kong. PATIENTS: Ninety-six neurologically impaired children who were treated with valproic acid between 1 July 1991 to 3 June 1999. The comparison group consisted of 48 children receiving antiepileptic drugs other than valproic acid. INTERVENTION: Low- or high-dosage valproic acid, using the threshold value of 40 mg/kg/d. MAIN OUTCOME MEASURES: Platelet count and liver function, duration of valproic acid treatment, dosage, and trough serum valproic acid concentration. RESULTS: Seventeen (17.7%) patients in the treatment group developed thrombocytopenia, compared with two (4.2%) in the comparison group (P<0.05). The platelet count was negatively correlated to serum valproic acid level and age, and positively correlated to polytherapy. The duration of valproic acid treatment was not a confounding factor in the age-related decrease in platelet count. Children with a trough level of >450 micromol/L or a daily dose of >40 mg/kg were more likely to develop thrombocytopenia. Thrombocytopenia was mild in most cases. CONCLUSIONS: A trough valproic acid level of >450 micromol/L or a daily dose of >40 mg/kg should alert the clinician to the risk of developing thrombocytopenia. The risk is further increased for older children. The platelet count should be monitored for patients receiving a high concentration of valproic acid who are also receiving drugs that would affect homeostasis, or who are undergoing surgical procedures.

Adolescent↗
PubMed2001

Classic late infantile neuronal ceroid lipofuscinosis in a Chinese patient.

Neuronal ceroid lipofuscinoses are a group of rare neurodegenerative disorders that are characterised by an accumulation of autofluorescent lipopigments in neurons and extraneuronal tissues. We report on a 4-year-old boy who presented with an acute onset of seizures followed by rapid psychomotor deterioration, ataxia, and visual failure. Photic stimulation at 1 to 3 Hz elicited discrete spike and wave discharges in the electroencephalogram, which were diminished at a higher frequency of stimulation. The electroretinogram was extinct. Magnetic resonance imaging of the brain showed generalised cerebral and cerebellar atrophy. Electron microscopic examination of lymphocytes and samples of muscle and skin revealed characteristic curvilinear inclusion bodies. To our knowledge, this is the first case of late infantile neuronal ceroid lipofuscinosis to be reported in a Hong Kong Chinese patient.

Aminopeptidases↗
PubMed2001

Clinical efficacy of proton pump inhibitor therapy in neurologically impaired children with gastroesophageal reflux: prospective study.

OBJECTIVE: To study the effects of proton pump inhibitors in reducing vomiting, gastrointestinal bleeding, and chest infections in institutionalised neurologically impaired children with gastroesophageal reflux. DESIGN: Prospective study. SETTING: A regional hospital, Hong Kong. PATIENTS: Neurologically impaired children with refractory gastroesophageal reflux. MAIN OUTCOME MEASURES: Episodes of vomiting, gastrointestinal bleeding, and pneumonia in the baseline and proton pump inhibitor treatment periods. RESULTS: Nine children received proton pump inhibitor therapy for a median duration of 81 days. Mean reflux index was 9.3% (standard deviation, 5%). Dosage of omeprazole used was 1.0-2.3 mg/kg/d. Vomiting was reduced significantly with proton pump inhibitor treatment (median vomiting index [baseline]=0.4, median vomiting index [proton pump inhibitors]=0.2; P<0.05). No significant decrease in gastrointestinal bleeding or chest infection was observed. CONCLUSION: Proton pump inhibitors significantly reduced vomiting episodes in neurologically impaired children with gastroesophageal reflux.

Child↗
PubMed2000

Baseline metal concentration in the Asian periwinkle Littorina brevicula employed as a biomonitor to assess metal pollution in Korean coastal water.

Concentrations of Al, Fe, Mn, Cu, Zn, V, Ni, Co, Cr, Cd and Pb in the Asian periwinkle Littorina brevicula were determined from 39 sampling locations along the whole Korean coast. Metal concentrations in the periwinkle varied highly with sampling stations, but the variations could be well explained by the body size after eliminating the data exceeding the 'High' criteria. Among the stations exceeding the 'High' criteria corresponding to mean plus one standard deviation of the logarithms of the individual site mean, some stations exhibited values higher than expected from the relationship between metal body burden and body size, indicating that these locations were polluted with metals. However, several 'High' stations followed the trends of the curve, suggesting that they resulted from the effect of their small body size, not from environmental contamination. Periwinkles of similar body sizes exhibited same range of metal concentrations in their body, independent of geographical position.

Animals↗
PubMed2000

Circadian rhythms, aging and memory.

In human beings and animal models, cognitive performance is often impaired in natural and experimental situations where circadian rhythms are disrupted. This includes a general decline in cognitive ability and fragmentation of behavioural rhythms in the aging population of numerous species. There is some evidence that rhythm disruption may lead directly to cognitive impairment; however, this causal link has not been made for effects due to aging. We have tested this link by examining rhythms and performance on contextual conditioning with the conditioned place preference task, in elderly, age-matched hamsters. Young healthy hamsters developed a preference for a context that is paired with the opportunity to engage in wheel-running (experiment 1). Aged animals with consolidated locomotor rhythms developed similar degrees of preference, whereas the age-matched hamsters with fragmented rhythms did not (experiment 2). The degree of preference was also correlated with activity amplitude. These results support the notion that age-related rhythm fragmentation contributes to the age-related memory decline.

Aging↗
PubMed2000

Circadian rhythms, aging and memory.

In human beings and animal models, cognitive performance is often impaired in natural and experimental situations where circadian rhythms are disrupted. This includes a general decline in cognitive ability and fragmentation of behavioural rhythms in the aging population of numerous species. There is some evidence that rhythm disruption may lead directly to cognitive impairment; however, this causal link has not been made for effects due to aging. We have tested this link by examining rhythms and performance on contextual conditioning with the conditioned place preference task, in elderly, age-matched hamsters. Young healthy hamsters developed a preference for a context that is paired with the opportunity to engage in wheel-running (experiment 1). Aged animals with consolidated locomotor rhythms developed similar degrees of preference, whereas the age-matched hamsters with fragmented rhythms did not (experiment 2). The degree of preference was also correlated with activity amplitude. These results support the notion that age-related rhythm fragmentation contributes to the age-related memory decline.

Aging↗