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Biomedical subjects

H S Wong

Publications and source records attributed to H S Wong.

At least 19 recordsLinked to original sources

The practice of episiotomy in public hospitals in Hong Kong.

OBJECTIVE: To review the use of episiotomy during vaginal delivery in Hong Kong public hospitals. DESIGN: Prospective observational survey. SETTING: Public hospitals, Hong Kong. PARTICIPANTS: Women who underwent normal vaginal delivery of a singleton foetus with cephalic presentation. MAIN OUTCOME MEASURES: Number of women having an episiotomy, severe-degree (third- or fourth-degree) tear, other types of tear, blood loss at delivery, postpartum haemorrhage, need for blood transfusion, puerperal pyrexia, wound infection, gaping wound that required suture removal, and drainage or resuturing of a perineal wound. RESULTS: Between 1 January and 31 March 2003, there were 6222 singleton spontaneous normal vaginal deliveries in the public hospitals of Hong Kong. Of the 6167 women in whom the status of the perineum was known, episiotomy was performed in 5274 (85.5%). Primiparous women were more likely to undergo episiotomy at delivery than multiparous women (97.9% vs 71.4%). Women with episiotomy had significantly less perineal tearing of any kind than those without. The occurrence of any type of perineal tear and severe-degree (third- or fourth-degree) tear was significantly lower in primiparous women who had an episiotomy than those without (P<0.05). Women with episiotomy had increased mean blood loss at delivery but other complications were not significantly increased. CONCLUSIONS: In Hong Kong, episiotomy is routinely performed during normal vaginal delivery. It is associated with a significantly lower overall rate of perineal tearing. This study was observational, nonetheless the occurrence of other complications was likely to increase when episiotomy was performed. Firm evidence from several randomised controlled studies shows that routine episiotomy is unjustified and possibly harmful. Routine episiotomy should not be promoted in Hong Kong without further randomised controlled study.

Adolescent↗

Quality of life in cadaver and living-related renal transplant recipients in Kuala Lumpur hospital.

OBJECTIVE: To examine the quality of life in cadaver (CAD) and living-related (LRRT) renal transplant recipients. METHODS: A cross-sectional study was done on patients followed in renal transplant clinic from 1/4/03 to 1/7/03 using the SF-36 questionnaire. Inclusion criteria were age >16 years,minimum of 3 months' posttransplant, and informed consent. Exclusion criteria were current treatment for rejection or infection or any life-threatening conditions. Information on duration of transplant, duration of dialysis prior to transplant, number of co-morbidities, and sociodemodraphic data were collected. RESULTS: Sixty-four among 110 patients (58.1%) completed the SF36 questionnaire. The LRRT recipients were younger, had a longer duration of transplant, and had spent significantly less time on dialysis prior to transplant compared to CAD transplant patients. Overall, the physical composite and the mental composite scores were not significantly different between the two transplant groups. Age was negatively associated with the physical composite score (Spearman's rho -0.251, P < .05) and bodily pain (Spearman's rho -0.266, P < .05). Duration of dialysis prior to transplant was negatively correlated with social functioning (Spearman's rho -0.28, P < .05) and mental health (Spearman's rho -0.39, P < .005). In multiple regression analysis, age was a significant predictor of the SF36 physical composite score (P < .05). CONCLUSION: This study shows that the quality of life between LRRT and CAD recipients was not significantly different. Increased age was associated with poorer physical capacity.

Adult↗

Body composition by bioelectrical impedance analysis in renal transplant recipients.

UNLABELLED: Bioelectrical impedance analysis was introduced more than a decade ago to measure body composition and nutritional status. There are presently limited data on the nutritional status and body composition measured with bioelectrical impedance analysis in renal transplant recipients, especially among the Asian population. The normal values for these data in renal transplant recipients remain unknown. METHODS: All renal transplant recipients with stable graft function who attended the outpatient renal transplant clinic in June 2003 were recruited for this cross-sectional study. Demographic and clinical data were obtained from participating patients and their outpatient clinic notes. Body composition and bioelectrical impedance data were obtained using the Metron BioScan 916 v3 analyzer. RESULTS: Out of a total of 168 renal transplant recipients, 110 participated in this study of body composition and bioelectrical impedance for comparison with data from a previous study of 419 normal healthy volunteer controls. When compared to the healthy Malaysians, renal transplant recipients showed similar body composition in terms of body mass index, body cell mass, muscle bulk, percentage of body fat, percentage of fat free mass, and percentage of total body water. However, renal transplant recipients have more extracellular water, a lower phase angle, and a lower reactant. CONCLUSION: Malaysians who have undergone renal transplantation have similar body composition to the healthy Malaysians when measurements are obtained using bioelectrical impedance analysis.

Adult↗

Reconstruction of shoulder function using a reflected long head biceps: a moment arm study.

A tendon transfer technique is proposed for the reconstruction of the paralyzed shoulders secondary to brachial plexus injury. This innovative technique does not require bone-to-bone or tendon to-bone fixation, and attempts to overcome other clinical limitations such as those due to insufficient length of donor muscle. The approach is referred to as the reflected long head biceps (RLHB) technique. The long head of biceps tendons is utilized as a bridging tendon graft. Two surgical alternatives, namely the through-deltoid (TD) pathway and the sub-deltoid (SD) pathway, were studied. The moment arms of the transferred tendons were assessed and reported. The TD technique yielded a larger moment than the SD technique. In the plane 30 degrees anterior to the scapular plane, the average moment arms were 3.8cm TD and 3.0cm SD at zero elevation. Such differences tended to further widen with increasing elevation. At 80 degrees elevation, the moment arms became 3.2cm TD and 1.2cm SD. The results supported the clinical feasibility of this RLHB tendon transfer approach.

Aged↗

The effect of fetal gender on nuchal translucency at 10-14 weeks of gestation.

Recent data have suggested that fetal nuchal translucency (NT) is affected by fetal gender. We investigated the size of this effect in 12 189 unselected pregnancies with known normal outcomes that had undergone NT measurements between 10 and 14 weeks of gestation. NT increased with gestation and was converted to multiples of the median (MoM) for the gestational day. The median NT MoM (95% CI) for female fetuses was 0.98 (0.97-0.99). This was significantly lower than that of the male fetuses (1.03; range 1.02-1.04) (p<0.0005; Wilcoxon rank-sum test). The gender difference was not observed at 10 weeks but was observed from 11 weeks onwards. There is no obvious explanation for the above findings.

Adult↗

Embryonic and fetal globins are expressed in adult erythroid progenitor cells and in erythroid cell cultures.

The understanding of human hemoglobin ontogeny during development is of biological and clinical importance. Molecular and immunocytological techniques were used to study the expression of embryonic zeta (zeta), epsilon (epsilon), and fetal gamma (gamma) globin genes in newborn cord blood, peripheral blood from men, pregnant and non-pregnant women, and in vitro mononuclear cell cultures. We have shown that embryonic and fetal globin mRNA and peptides are expressed in cultured erythroid cells and in circulating blood cells from newborns, adult non-pregnant women and from men. The findings suggest that during erythroid cell differentiation in newborns and adults, there is a transient recapitulation of sequential globin chain expression as found during embryonic and fetal development. Furthermore, these findings underscore the need for caution in using embryonic and fetal globin chains as markers to identify erythroid cells of fetal origin in maternal circulation for prenatal diagnosis.

Adult↗

Quantitative polymerase chain reaction for the rapid prenatal diagnosis of homozygous alpha-thalassaemia (Hb Barts hydrops fetalis).

A quantitative polymerase chain reaction (Q-PCR) method based on the TaqMan technology has been devised for the prenatal diagnosis of homozygous alpha*-thalassaemia (south-east Asian type deletion). Primers and TaqMan probes were designed to specifically amplify an alpha*-thal chromosomal fragment or a normal alpha-chromosomal fragment. Variations in input target DNA in individual sample wells were normalized by the simultaneous amplification of a beta-actin gene fragment and results expressed as a ratio to that of beta-actin. There was no overlap of the data between the homozygous alpha*-thal, alpha*-thal and normal subjects. Up to 5% maternal DNA (alpha*-thal) contamination did not affect the specificity of the result. In 31 prenatal diagnoses, the result using Q-PCR compared favourably with the gold standard of Southern hybridization of alpha-genes.

Actins↗

Stability of reconstructed paralyzed shoulders using a reflected long head biceps technique.

A new tendon transfer technique is proposed for the reconstruction of the paralyzed shoulders secondary to Brachial Plexus Injury (BPI). In this tendon transfer, the long head of the biceps tendons is utilized as a bridging tendon graft. It is reflected at the exit of the bicipital groove, passed through the deltoid and directed to the trapezius. The technique is referred to here as the Reflected Long Head Bicepts (RLHB) technique. This study evaluated the effect of this tendon transfer on the anterior, posterior, and inferior stability of the reconstructed should using cadaveric specimens. It was shown that loading of the RLHB contributed significantly to anterior stability of the reconstructed shoulder for 90 deg elevation in the scapula plane. The mean displacement was reduced by 56 percent with RLHB loaded (p<0.01), by 56 percent with the rotator cuff loaded (p <0.005), and by 67 percent with both the RLHB and the rotator cuff loaded (p<0.004). For the post-operation conditions, variation of the directions of RLHB had no significant effect on joint displacement in response to anterior loading. The RLHB tendon also contributed to the posterior and inferior stability for the low and middle elevations in the plane of scapula. Two variations of the RLHB tendon transfer procedures, namely the "Sub-Deltoid" and the "Through-Deltoid" techniques, were introduced and studied. These two techniques did not seem to have significantly different effects on the displacement of the humeral head in response to both posterior and inferior loading. The results of this study seemed to support the clinical feasibility of this tendon transfer approach as far as the biomedical stability of the reconstruction is concerned.

Adult↗

Conducting research on the Medicare market: the need for better data and methods.

OBJECTIVE: To highlight data limitations, the need to improve data collection, the need to develop better analytic methods, and the need to use alternative data sources to conduct research related to the Medicare program. Objectives were achieved by reviewing existing studies on risk selection in Medicare HMOs, examining their data limitations, and introducing a new approach that circumvents many of these shortcomings. DATA SOURCES: Data for years 1995-97 for five states (Arizona, Florida, Massachusetts, New York, and Pennsylvania) from the Healthcare Cost and Utilization Project (HCUP) State Inpatient Databases (SIDs), maintained by the Agency for Healthcare Research and Quality; and the Health Care Financing Administration's Medicare Managed Care Market Penetration Data Files and Medicare Provider Analysis and Review Files. STUDY DESIGN: Analysis of hospital utilization rates for Medicare beneficiaries in the traditional fee-for-service (FFS) Medicare and Medicare HMO sectors and examination of the relationship between these rates and the Medicare HMO penetration rates. PRINCIPAL FINDINGS: Medicare HMOs have lower hospital utilization rates than their FFS counterparts, differences in utilization rates vary across states, and HMO penetration rates are inversely related to our rough measure of favorable selection. CONCLUSIONS: Substantial growth in Medicare HMO enrollment and the implementation of a new risk-adjusted payment system have led to an increasing need for research on the Medicare program. Improved data collection, better methods, new creative approaches, and alternative data sources are needed to address these issues in a timely and suitable manner.

Aged↗

Acceptability of serum screening as an alternative to cytogenetic diagnosis of down syndrome among women 35 years or older in Hong Kong.

The addition of second trimester serum markers to maternal age increases the efficacy of screening for Down syndrome by maternal age alone. Among women aged 35 years or older, serum screening makes a large proportion of amniocentesis unnecessary. However, there are ethical and medicolegal concerns about serum screening in 'old' women, largely because some of the pregnancies affected by Down syndrome and other chromosomal abnormalities may not be detected. We investigated the acceptability of serum screening in women aged 35 years or older when it was offered as an alternative to prenatal cytogenetic diagnosis after detailed counselling. Women referred for prenatal diagnosis of Down syndrome because of advanced maternal age were given the options of cytogenetic diagnosis by chorionic villus sampling (CVS) or amniocentesis. As an alternative, they could choose to undergo second trimester serum human chorionic gonadotrophin (hCG) and alpha-fetoprotein (AFP) screening first before deciding on whether to undergo amniocentesis. Between January 1997 and October 1999, 3419 subjects were recruited. 1807 women (52. 9%) chose to undergo serum screening, 1516 women (44.3%) chose to have amniocentesis and 96 women chose to have CVS (2.8%). The proportion of women who chose serum screening rose steadily from 38. 8% in the year of 1997 to 63.4% in 1999. Significantly fewer Chinese women chose serum screening than non-Chinese. The decision as to whether to undergo an invasive diagnostic procedure or to be content with the relatively safer but less accurate screening test varies, being affected by the women's background and culture.

Adult↗

Selection bias in HMOs: a review of the evidence.

Early reviews found that health maintenance organizations (HMOs) attracted healthier beneficiaries in the Medicare program and healthier employees in the market for employer-based insurance. This review finds that HMOs still attract healthier Medicare beneficiaries, that HMOs no longer attract healthier employees, and that HMOs attract healthier Medicaid recipients. This review also found conflicting evidence about whether Medicare HMOs are overpaid, no evidence that HMOs are overpaid in the market for employer-based insurance, and evidence that concerns about overpaying Medicaid HMOs have diminished because many states are adopting mandatory programs.

Fees and Charges↗

The marginal benefits of invasive treatments for acute myocardial infarction: does insurance coverage matter?

This paper applies instrumental variable (IV) techniques and estimates the average benefits of invasive surgical treatments for marginal acute myocardial infarction (AMI) patients by insurance coverage. The study uses data from the Agency for Healthcare Research and Quality's Healthcare Cost and Utilization Project (HCUP), State Inpatient Databases for the state of Washington, for years 1988-1993. We observed differences in average benefits for marginal patients across insurance subpopulations that cannot be explained by differences in measured clinical circumstances. Our empirical results show that the insurance subpopulations with the greatest estimated marginal benefits are those with the lowest expected payment generosity to providers. Because of the relatively weak explanatory power of our instruments for three insurance subpopulations, and because many of the parameter estimates across the insurance subpopulations are not statistically different from each other, policy recommendations should be approached cautiously. However, our application of IV techniques to AMI patients demonstrates the usefulness of this approach to estimate treatment effects across patient populations (e.g., across types of insurance coverage) for medical conditions of interest to policymakers. These estimates may help determine whether treatments are overutilized or underutilized.

Adult↗

Histological findings in a case of alobar holoprosencephaly diagnosed at 10 weeks of pregnancy.

A case of alobar holoprosencephaly diagnosed at 10 + 3 weeks' gestation by transabdominal and transvaginal ultrasound examination followed by histological confirmation is presented. The diagnosis was based on two sonographic criteria: intracranial finding of a single ventricle with a mantle and no visible midline structures but fusion of the thalami and corpus striatum, and facial abnormalities, including hypotelorism and proboscis. The fetal karyotype was triploidy. The ultrasound findings were confirmed by pathological examination. The histological findings of proboscis, single lens and single ventricle with neural tissue remnants are presented.

Adult↗

Evaluation of short-tether bis-THA AChE inhibitors. A further test of the dual binding site hypothesis.

To provide a further test of the dual binding site hypothesis proposed for acetylcholinesterase (AChE) inhibitor heptylene-linked bis-(9-amino-1,2,3,4-tetrahydroacridine) A7A, short-tether (ethylene hexylene) homologs A2A-A6A were prepared. En route to these compounds, convenient and scaleable syntheses of useful pharmaceutical intermediate 9-chloro-1.2,3,4-tetrahydroacridine 3 and A7A were developed. AChE and butyrylcholinesterase (BChE) inhibition assays of A2A-A10A confirm that a seven methylene tether (A7A) optimizes AChE inhibition potency and AChE/BChE selectivity. Finally, these studies indicate that simultaneous binding of alkylene-linked 9-amino-1,2,3,4-tetrahydroacridine dimers to the catalytic and peripheral sites of AChE is possible with a tether length as short as 5 methylenes.

Acetylcholinesterase↗

First-trimester ultrasound diagnosis of holoprosencephaly: three case reports.

We present three cases of fetal holoprosencephaly diagnosed by transabdominal and transvaginal ultrasound examinations at 10 and 13 weeks' gestation. The diagnosis was based on two sonographic criteria: first, the intracranial finding of a single ventricle with a cerebral mantle and no visible midline structures but fusion of the thalami and corpus striatum; and, second, facial abnormalities, including hypotelorism. The ultrasound findings were confirmed by embryoscopy before abortion in one case and by pathological examination after abortion in two cases. Chromosome study of the three fetuses showed trisomy 18, triploidy and mosaic 18p deletion and duplication.

Abortion, Therapeutic↗