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Biomedical subjects

S F Chan

Publications and source records attributed to S F Chan.

11 recordsLinked to original sources
PubMed2002

Acute pain services in Hong Kong: facilities, volume, and quality.

Acute pain services in public hospitals in Hong Kong were studied. Audit data on the volume and quality of acute pain services were collected prospectively from 1997 to 1999, and data on related facilities were collected in 2000. About 20% of patients undergoing a major operation received an acute pain service; of these, 78.6% were satisfied with the treatment provided. In 2000, 86% (18/21) of hospitals providing anaesthetic services were running an acute pain service. Staffing was better in hospitals providing a high volume of acute pain services, ranging from a full-time specialist anaesthesiologist assisted by a half-time trainee to a half-time specialist assisted by a full- or half-time trainee. However, only four hospitals were staffed with pain nurses. In total, 57% of patients received intravenous patient-controlled analgesia and 32% epidural analgesia. The mean duration of acute pain service treatment was 3.1 days. Currently anaesthesiologist-based acute pain services take care of a limited number of patients. To expand the coverage, there should be a move towards an anaesthesiologist-led, pain nurse-based, acute pain service. The present shortage of pain nurses should be addressed.

Analgesia, Patient-Controlled↗
PubMed2001

An NMDA receptor signaling complex with protein phosphatase 2A.

Regulation of protein phosphatase 2A (PP2A) activity and NMDA receptor (NMDAR) phosphorylation state contribute to the modulation of synaptic plasticity, yet these two mechanisms have not been functionally linked. The NMDAR subunit NR3A is equipped with a unique carboxyl domain that is different from other NMDAR subunits. We hypothesized that the NR3A C-terminal intracellular domain might serve as synaptic anchor for the phosphatase in the developing CNS. A cDNA library was screened by the yeast two-hybrid method using the NR3A carboxyl domain as the bait. The catalytic subunit of the serine-threonine PP2A was found to be associated with the NR3A carboxyl domain. Immunoprecipitation studies indicated that the NR3A subunit formed a stable complex with PP2A in the rat brain in vivo. Association of PP2A with NMDARs led to an increase in the phosphatase activity of PP2A and the dephosphorylation of serine 897 of the NMDAR subunit NR1. Stimulation of NMDARs led to the dissociation of PP2A from the complex and the reduction of PP2A activity. A peptide corresponding to the PP2A-NR3A binding domain functioned as a negative regulator of PP2A activity. These data suggest that NMDARs are allosteric modulators of PP2A, which in turn controls their phosphorylation state. The data delineate a mechanistic model of the dynamic regulation of a PP2A-NMDAR signaling complex, mediated by the interaction of NR3A and PP2A, and suggest a novel NMDAR-mediated signaling mechanism in addition to the traditional ionotropic functions of NMDARs.

Allosteric Regulation↗
PubMed2001

Indigenization and beyond: methodological relationalism in the study of personality across cultural traditions.

A brief intellectual history of the indigenization movement in Asia leads to the thesis that the generation of psychological knowledge is culture dependent. Indigenous psychologies go further and insist on viewing a target group from the natives' own standpoint. Psychological decentering underlies conceptions of human existence rooted in Asian intellectual traditions, in particular, relatedness between persons predominates in Confucianism. These conceptions demand new approaches to knowledge generation that signify a paradigmatic shift from methodological individualism to methodological relationalism. An implication is that relationships precede situations in the study of personality and social behavior. We define personality as the sum total of common attributes manifest in, and abstracted from, a person's behavior directly or indirectly observed across interpersonal relationships and situations over time. We rely on the notion that there are identifiable levels of cognition to develop a metatheoretical framework for reconstructing selfhood. Confronting the subject-object dichotomy opens the door to investigations of transcendent consciousness; confronting the self-other demarcation underlying Western theories leads to the construction of self-in-relations.

Cross-Cultural Comparison↗
PubMed2001

Anaesthetic clinical indicators in public hospitals providing anaesthetic care in Hong Kong: prospective study.

OBJECTIVES: To assess the quality of anaesthetic services as defined in the six anaesthetic clinical indicators against preset standards and to identify risk factors for adverse events in the recovery room. DESIGN: Prospective study. SETTING: All public hospitals providing anaesthetic care in Hong Kong. PATIENTS: Eighteen thousand, seven hundred and fifty-nine patients receiving elective or emergency anaesthesia administered by anaesthetists from June 1998 to July 1998. MAIN OUTCOME MEASURES: Patient demographics, American Society of Anesthesiologists status, category and nature of operation, presence of preoperative anaesthetic visit in ward, type of anaesthesia, reasons for a recovery room stay of more than a 2-hour duration, intubation to relieve respiratory distress in the recovery room, presence of hypothermia in the recovery room for operations lasting more than 2 hours, and dental or ocular injuries attributable to anaesthesia. RESULTS: There are two major findings from this study. Firstly, a high incidence of hypothermia in the recovery room was reported. Secondly, a greater risk of prolonged stay in the recovery room was identified for patients older than 65 years, major operations, and anaesthetic techniques using combined general and regional anaesthesia. CONCLUSION: The six anaesthetic clinical indicators reflected the provision of anaesthetic care in public hospitals in Hong Kong. Good compliance to the preset standard of the anaesthetic clinical indicators was achieved during the study period.

Adolescent↗
PubMed1998

Knowledge, attitudes and behaviours related to HIV and AIDS among chinese adolescents in hong kong.

The purpose of this study was to assess HIV and AIDS knowledge and attitudes, source of HIV and AIDS information, and behaviours related to HIV and AIDS among Chinese adolescents in Hong Kong. Participants included 1259 (826 females and 433 males) Chinese adolescents in Hong Kong between 12-18 years of age. Findings revealed that over 80% of the adolescents had rarely or never discussed HIV and AIDS with their family or teacher, and the primary source of HIV and AIDS information was media sources such as television and newspapers. Findings revealed HIV and AIDS misinformation among both male and female adolescents in the areas of transmission, facts, personal vulnerability and attitudes. However, participants reported engaging in little at-risk behaviour associated with HIV and AIDS. Implications for HIV and AIDS education and prevention are discussed.

Acquired Immunodeficiency Syndrome↗
PubMed1993

Dexamethasone decreases somatostatin mRNA levels in the periventricular nucleus of the rat hypothalamus.

Glucocorticoid excess inhibits somatic growth in man and laboratory animals. While the mechanism involved is likely to be multifactorial, indirect evidence suggesting the role of an enhanced endogenous somatostatin (SS) tone has been reported. However, there has been no direct evidence indicating an increased synthesis or secretion of hypothalamic SS. In this study, we investigated the effects of glucocorticoids on hypothalamic SS expression by measuring the peptide and mRNA content of SS in whole hypothalamic blocks of male Sprague-Dawley rats sacrificed 4 weeks after adrenalectomy or sham operation. Adrenalectomy decreased the SS content in the rat hypothalamus (p < 0.05), an effect which was reversed by dexamethasone treatment for 10 days. On the other hand, total hypothalamic SS mRNA levels were unaffected by adrenalectomy, but became significantly decreased following dexamethasone treatment (p < 0.05). Using in situ hybridization, this reduction in SS gene expression was shown to occur consistently in the periventricular nucleus and in the parvocellular subdivision of the paraventricular nucleus. The effects of adrenalectomy and dexamethasone on SS mRNA levels were further quantitated in hypothalamic fragments containing predominantly the periventricular and paraventricular nuclei. Somatostatin mRNA levels in these tissue fragments were marginally increased by adrenalectomy (p < 0.05), but showed a 50% reduction following dexamethasone treatment (p < 0.0001). In conclusion, our findings suggest that the inhibitory effect of glucocorticoids on somatic growth is probably not mediated via an effect on hypothalamic SS gene expression.

Adrenalectomy↗
PubMed1989

Mass spectrometric identification and quantification of 5-methoxytryptophol in quail retina.

The occurrence of 5-methoxytryptophol (5-MTL) in the quail retina was investigated by capillary column gas chromatography/mass spectrometry/selected ion monitoring using a deuterated internal standard. Based on ion intensity ratios in the mass spectra of pentafluoropropionyl and heptafluorobutyryl derivatives of 5-MTL and deuterated 5-MTL, 5-MTL was unequivocally identified in the quail retina. Similar to the circadian rhythm of retinal melatonin, retinal 5-MTL also exhibited a diurnal variation with high levels at mid-dark. However, no significant correlation between the diurnal levels of 5-MTL and melatonin was observed in the quail retina at mid-light or mid-dark.

Animals↗
PubMed1989

Changes in histamine and prostaglandins in acute inflammatory air pouch in mice.

The changes in histamine and prostaglandins (PGE2 and PGF) in carrageenan-induced acute inflammation were studied in 6 day old air pouches in mice. A significant elevation of exudate histamine was found 1 hour after the carrageenan injection. Highest vascular permeability at the site of inflammation was also found at 1 hour. Both PGE2 and PGF showed steady increases in the pouch exudate and reached significantly higher levels at 24 hours. The present findings thus suggest that histamine is involved in the early phase of carrageenan-induced inflammation by enhancing vascular permeability. The increases in PGE2 and PGF appear to be closely correlated with the increased exudate cell accumulation. This leads us to suggest that they are likely to be involved in the exudate cell activity rather than in enhancing the vascular permeability which was found to decrease at 4 hours after the carrageenan injection.

Animals↗
PubMed1981

Semiaqueous potentiometric determinations of apparent pKa1 values for benzothiadiazines and detection of decomposition during solubility variation with pH studies.

Apparent acidity constants obtained for various benzothiadiazine diuretics by semiaqueous potentiometric titrations gave satisfactory agreement with many values obtained by aqueous potentiometry. One suitable method for determining the acidity constants of sparingly soluble drugs, the solubility variation with pH technique, does not take into account instability problems. The preparation of decomposition products and the TLC analysis of sample solutions at various time intervals during solubility studies of methyclothiazide and bendroflumethiazide indicated that decomposition takes place during agitation and equilibration. This decomposition in buffers of pH 8 and higher was confirmed with the acidified p-dimethylaminobenzaldehyde test for primary aromatic amines.

Benzothiadiazines↗