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Biomedical subjects

C H Li

Publications and source records attributed to C H Li.

At least 19 recordsLinked to original sources
PubMed2007

Intraspinal and intracranial hemorrhage after lumbar puncture.

Two cases of spinal epidural hematoma and two cases of intracranial subdural hematoma after lumbar puncture (LP) are reported in children receiving chemotherapy for acute lymphoblastic leukemia and non-Hodgkin lymphoma. The bleeding was asymptomatic but interfered with treatment in one case, and caused either severe backache or headache but no neurological deficit in the other three patients. The platelet counts were 8 and 46 x 10(9)/L in two patients and were normal in the other patients at the time of LP. All recovered without surgical treatment. There is an inherent, albeit uncommon, risk of bleeding into the central nervous system associated with LP in children with cancer and should be distinguished from postdural puncture headache (PDPH). Thrombocytopenia is not always an accompanying factor.

Adolescent↗
PubMed2006

Evaluation of quality of life using ASQoL questionnaire in patients with ankylosing spondylitis in a Chinese population.

The purpose of this study was to evaluate the reliability of Chinese version of the ankylosing spondylitis quality of life questionnaire (ASQoL) for AS patients. All the enrolled AS patients should fulfill five questionnaires (BASDAI, BASFI, DFI, BAS-G and ASQoL) by himself, then the investigators did physical examination of the patients, fulfilling BASMI. Physical function has a strong correlation with QoL in patients with AS. In different disease activity groups, ASQoL had a correlation with BASFI, especially in the moderate activity group (gamma = 0.66, P < 0.0001). All four questionnaires in entanacept treatment group improved distinctly on week 6 and 12 comparing to baseline. There were significantly correlations of changing between ASQoL and BAS-G, BASDAI and BASFI after treatment with etanercept in AS patients. The Chinese ASQoL questionnaire is valuable to evaluate the activity of AS patients and effect of biologic agent treatment in patients with AS. It is a good generic instrument to measure QoL in patients with AS in China.

Activities of Daily Living↗
PubMed2006

The impact of a management protocol on the outcomes of child abuse in hospitalized children in Hong Kong.

OBJECTIVE: To study the outcomes of children hospitalized for suspected child abuse before and after the implementation of a management protocol in a hospital in Hong Kong. STUDY PERIOD: Two 2-year periods before (1994-1995) and after (2002-2003) the implementation of the protocol in 1998. METHODS: This is a retrospective hospital chart review in which the patients' characteristics, the use of laboratory and radiological examination, abuse substantiation and official registrations are compared between the two study periods. RESULTS: There were 109 and 320 patients admitted for evaluation of child abuse for the periods 1994-1995 and 2002-2003, respectively. Children in both periods were similar in sex ratio, proportion of severe forms of child abuse, rates of abuse substantiation and inclusion in the Child Protection Registry. After the implementation of a management protocol, there has been a significant drop in the proportion of children subjected to investigations such as blood counts (86% vs. 16%, p<.001), clotting study (75% vs. 9%, p<.001), and skeletal survey (78% vs. 6%, p<.001). The average length of hospital stay also dropped from 15.3 days to 6.1 days (p<.001). CONCLUSIONS: There has been an almost threefold rise in the number of child abuse cases handled at the hospital during the 10-year interval. With the implementation of a management protocol, only a small proportion of children need laboratory investigations or skeletal survey without any drop in abuse substantiation and official registration. The length of hospital stay has also been significantly reduced.

Adolescent↗
PubMed2006

Role of secreted frizzled-related protein 1 (SFRP1) in wound healing.

Wound healing is a complex cascade of events, which diminishes the size of the wound and reestablishes tissue integrity. Secreted frizzled-related protein 1 (SFRP1) contributes to the inhibition of apoptosis in fibroblast populations. We investigated the role of SFRP1 in a mouse wound-healing model; 2.0-mm excisional wounds were created in the scalp and hard palate. Healing responses were measured by histomorphometric analysis, apoptosis assay, and immunohistochemistry. Dermal wounds did not harbor SFRP1, but healed faster than palatal wounds which expressed significant levels of SFRP1. Antibody experiments aimed at blocking SFRP1 in palatal wounds resulted in promotion of wound closure, enhancement of new tissue formation, decrease of inflammatory cell infiltrate, and increase of apoptotic fibroblasts. Analysis of the present data suggests that SFRP1 may be partly responsible for the poorer healing performance of the palatal wounds compared with dermal wounds. Blocking SFRP1 results in improvement of palatal healing outcomes.

Animals↗
PubMed2006

Neonaticide, newborn abandonment, and denial of pregnancy--newborn victimisation associated with unwanted motherhood.

We report two cases of newborn death and two cases of near-miss newborn death. One neonate was strangled to death after delivery in the hospital and one died from lethal congenital malformations. The third was found on the verge of death after being abandoned in a dumpster. The fourth was rescued from the toilet bowl by the mother's boyfriend while the mother was in a state of panic. In the three cases where the infants' maternal identities were known, the women were all primiparous and aged 22, 13, and 17 years. The paternity was extramarital, incestuous, and concealed, respectively. Denial or concealment of pregnancy was present in all cases, but none of the women had any overt psychiatric manifestations at the time of delivery. Neonaticide and newborn abandonment are closely associated with denial of pregnancy, and are serious forms of childhood victimisation. Their occurrence in Hong Kong is poorly understood and no representative figures are available. A concerted effort among the health care, social work, and judicial professionals is needed to define the scope of the problem and devise preventive measures.

Adolescent↗
PubMed2006

Acute massive haemolysis in children with glucose-6-phosphate dehydrogenase deficiency.

We report seven consecutive episodes of acute massive haemolysis accompanied by symptomatic anaemia and gross haemoglobinuria in six boys with glucose-6-phosphate dehydrogenase deficiency seen in a regional hospital during a 12-year period. They presented at a mean age of 5.5 years (range, 1.5-11.3 years) with trough haemoglobin levels between 35 and 84 g/L. Two children developed transient renal impairment. Five children required erythrocyte transfusion, of whom one underwent exchange transfusion during the oliguric phase. Three patients required intensive care but all recovered from the haemolysis. The probable precipitating factors included consumption of fava beans (n=2), exposure to mothballs (n=1), treatment with herbal medicine or intramuscular injection of unknown nature (n=3), and upper respiratory tract infection (n=1). Although uncommon, acute massive haemolysis remains a life-threatening complication in children with glucose-6-phosphate dehydrogenase deficiency. Improvement in patient education and public health measures is suggested.

Anemia, Hemolytic↗
PubMed2005

Interface magnetization reversal and anisotropy in Fe/AlGaAs(001).

The reversal process of the Fe interface layer magnetization in Fe/AlGaAs heterostructures is measured directly using magnetization-induced second-harmonic generation, and is compared with the reversal of the bulk magnetization as obtained from magneto-optic Kerr effect. The switching characteristics are distinctly different due to interface-derived anisotropy--single step switching occurs at the interface layer, while two-jump switching occurs in the bulk Fe for the magnetic field orientations employed. The angle between the interface and bulk magnetization may be as large as 40-85 degrees. Such interface switching will dominate the behavior of nanoscale structures.

Journal Article↗
PubMed2005

Vertebroplasty by use of a strontium-containing bioactive bone cement.

STUDY DESIGN: A review of the laboratory and clinical data for a new strontium-containing hydroxyapatite bioactive bone cement. OBJECTIVES: To compare the properties of the strontium-containing bioactive bone cement with those of polymethyl methacrylate (PMMA) and hydroxyapatite (HA) bone cements. SUMMARY OF BACKGROUND DATA: Vertebroplasty and kyphoplasty using conventional PMMA bone cements have been effectively used to treat osteoporotic spine fractures with good short- and medium-term results. However, PMMA has some undesirable properties, including its high setting temperature, lack of osseointegration, and large stiffness mismatch with osteoporotic bone. These properties are responsible for some postoperative complications. METHODS: Strontium-containing hydroxyapatite (Sr-HA) bioactive bone cement consists of a filler blend of strontium-containing hydroxyapatite, fumed silica and benzoyl peroxide; and a resin blend of bisphenol A diglycidylether methacrylate, triethylene glycol dimethacrylate, poly(ethylene glycol) methacrylate, and N, N-dimethyl-p-toluidine. Its properties, including mechanical strength, setting temperature, biocompatibility, and osseoinduction, were compared with other cements in vitro and in vivo. Early clinical results are presented. RESULTS: The Sr-HA cement has a setting time of 15 to 18 minutes, a maximum setting temperature of 58 degrees C, a compressive strength of 40.9 MPa, bending strength of 31.3 MPa, and a bending modulus of 1,408 MPa. The bending strength and modulus are closer to human cancellous bone. Sr-HA cement promotes osteoblast attachment and mineralization in vitro and bone growth and osseointegration in vivo. In a pilot study, 23 cases of osteoporotic fractures treated with this cement with a mean follow-up of 18 months suggest that it is as effective as PMMA in relieving pain. DISCUSSIONS: Oral strontium has been shown to induce new bone formation and is effective in reducing fracture risk in osteoporosis. Our data suggest that strontium delivered locally has the same effect; thus, the combination of strontium with HA in a cement with a low setting temperature, adequate stiffness, and low viscosity makes this a good bioactive cement for vertebroplasty and kyphoplasty.

Animals↗
PubMed2004

Reactive oxygen species are crucial for hydroxychavicol toxicity toward KB epithelial cells.

Betel quid (BQ) chewing shows a strong correlation to the incidence of oral submucous fibrosis (OSF), leukoplakia and oral cancer. BQ contains mainly areca nut, lime, Piper betle leaf (PBL) and the inflorescence of P. betle (IPB). Hydroxychavicol (4-allyl-catechol, HC), as a major phenolic compound in PBL and IPB, is shown to induce oxidative stress, glutathione (GSH) depletion and cell cycle deregulation. Using bivariate BrdU/PI flow cytometry, KB cells in DNA synthesis (S phase) are shown to be sensitive to the toxic effect of HC and show cell cycle arrest and apoptosis following exposure to 0.1 and 0.3 mM HC. HC-induced apoptosis and cell cycle arrest are associated with mitochondrial membrane potential (delta Psim) depolarization as revealed by a decrease in rhodamine fluorescence. N-acetyl-L-cysteine (1 mM), superoxide dismutase (100 U/ml) and catalase (1000 U/ml) were effective in prevention of HC-induced GSH depletion (as indicated by chloromethylfluorescein fluorescence), reactive oxygen species (ROS) production (by dichlorofluorescein fluorescence), cell cycle arrest and apoptosis. However, dimethylthiourea (2 mM), neocuproine (1 mM), 1,10-phenanthroline (200 microM) and desferrioxamine (0.5 mM) showed little effect on HC-induced cell changes. HC elevated the cellular and mitochondrial GSH levels at moderate concentrations (0.05-0.1 mM), whereas at a concentration of 0.3 mM, inhibitory effects were noted. These results indicate that HC consumption may be associated with BQ-chewing-related oral mucosal diseases via GSH depletion, ROS production, mitochondrial dysfunction, cell cycle disturbance and the induction of apoptosis. These events are related to the production of superoxide radicals and hydrogen peroxide.

Antioxidants↗
PubMed2004

Bronchoscopic Nd-YAG laser surgery for tracheobronchial mucoepidermoid carcinoma--a report of two cases.

Mucoepidermoid carcinoma (MEC) of the tracheobronchial tree represents 0.2% of all lung tumours. It arises from the excretory ducts of the bronchial mucosa and is classified into low- and high-grade tumours using criteria derived from similar tumours of the major salivary glands. Low-grade MEC behaves in a benign fashion with less parenchymal and hilar lymph nodal invasion. The traditional method of treatment is by thoracotomy. The bronchoscopic approach to this lesion using lasers has rarely been reported. This article reports two cases of low-grade tracheobronchial MEC, which were both managed through bronchoscopic neodymium yttrium aluminium garnet (Nd-YAG) laser surgery. The patients were free from disease, 26 and 36 months after surgery. Bronchoscopic laser surgery promises to be an effective alternative treatment modality for tracheobronchial MEC. It is minimally invasive, results in less hospital stay and does not impair pulmonary functions.

Adult↗
PubMed2003

Symptomatic venous thromboembolism in Hong Kong Chinese children.

OBJECTIVE: To determine the incidence of venous thromboembolic disease in children of Chinese origin, and associated predisposing factors. DESIGN. Retrospective case series. SETTING: A general, public hospital serving a population of approximately 181,000 children in Hong Kong. PATIENTS AND METHODS: Hong Kong Chinese children under the age of 15 years who were diagnosed with a symptomatic venous thromboembolic event between 1995 and 2000 were included. Data on clinical features, predisposing factors, treatment, and outcome were obtained from review of hospital medical records. RESULTS: Eight children (five girls and three boys) of mean age 11.5 years (range, 0-14.7 years) were included in the study. They presented with deep vein thrombosis (n=4, with pulmonary embolism in one), superior vena cava thrombosis (n=1), and cerebral venous sinus thrombosis (n=3). Predisposing factors included hereditary protein C deficiency (n=3), protein S deficiency (n=2), anticardiolipin antibodies (n=1), malignancy (n=3), recent neurosurgery (n=2), infection (n=1), with multiple predisposing factors seen in three patients. Anticoagulant therapy was prescribed in five patients, and long-term warfarin therapy was required in two cases. Venous thromboembolic disease resolved in all children, but one patient had a recurrence after cessation of warfarin therapy, and one patient had post-thrombotic syndrome. CONCLUSION: The rate of venous thromboembolic disease in Hong Kong Chinese children was comparable to that seen in Caucasian children, with an annual incidence of 0.74 per 100,000 children. Predisposing factors, including hereditary prothrombotic conditions, were common.

Adolescent↗
PubMed2002

Hydrogen adsorption on the indium-rich indium phosphide (001) surface: a novel way to produce bridging In-H-In bonds.

The indium phosphide (001) surface provides a unique chemical environment for studying the reactivity of hydrogen toward the electron-deficient group IIIA element, indium. Hydrogen adsorption on the In-rich delta(2 x 4) reconstruction produced a neutral, covalently bound bridging indium hydride. Using vibrational spectroscopy and ab initio cluster calculations, two types of bridging hydrides were identified, a (mu-H)In(2) and a (mu-H)(2)In(3) "butterfly-like" structure. These structures were formed owing to the large thermodynamic driving force for adsorption of H atoms on solid-state indium dimers.

Journal Article↗
PubMed2001

Catalytic nucleophilic acyl substitution of anhydrides by amphoteric vanadyl triflate.

[reaction--see text] Among four vanadyl species examined, vanadyl triflate was the most efficient catalyst to facilitate nucleophilic acyl substitution of anhydrides with a myriad array of alcohols, amines, and thiols in high yields and high chemoselectivity. By using mixed-anhydride technique, one can achieve oleate and peptide syntheses. In marked contrast to common metal triflates, the amphoteric character of the V=O unit in vanadyl species was proven to be responsible for the catalytic profile in this process.

Journal Article↗
PubMed2001

Catalytic asymmetric coupling of 2-naphthols by chiral tridentate oxovanadium (IV) complexes.

A series of chiral oxovanadium(IV) complexes derived from tridentate N-3,5-substituted and N-3,4-benzo- and N-5,6-benzo-salicylidene-alpha-amino acids can serve as efficient catalysts for the enantioselective oxidative couplings of various 3-, 6-, and 7-substituted 2-naphthols under O(2). The best scenario involves the use of a vanadyl complex arising from 2-hydroxy-1-naphthaldehyde and valine (or phenylalanine) in CCl(4), leading to BINOLs in good yields (75-100%) and with enantioselectivities of up to 68%.

Journal Article↗