Biomedical subjects

G S H Yeo

Publications and source records attributed to G S H Yeo.

15 recordsLinked to original sources

PubMed2006

Does HLA-B27 influence the monocyte inflammatory response to lipopolysaccharide?

OBJECTIVES: How human leucocyte antigen B27 (HLA-B27) contributes towards arthritis susceptibility is still unclear, but effects on the response to bacteria unrelated to the classical antigen presenting role of B27 have been suggested. This study investigated whether HLA-B27 modulates the innate response to lipopolysaccharide (LPS), a component shared between all Gram negative bacteria that can trigger reactive arthritis. METHODS: Pools of U937 transfectants expressing either HLA-B27, HLA-A2 or the expression plasmid alone were differentiated with phorbol 12-myristate 13-acetate and stimulated with LPS. Supernatants were analysed for tumour necrosis factor-alpha (TNF-alpha) secretion and the gene expression profiles of unstimulated and LPS-stimulated cells were determined by microarray analysis. Changes in gene expression that are indicative of an unfolded protein response (UPR) were also analysed by quantitative polymerase chain reaction (PCR). RESULTS: TNF-alpha secretion, a biological marker of the inflammatory response to LPS, was not significantly different between U937-B27 and U937-control. No differences in gene expression between unstimulated U937-B27 and U937-control lines were detected. Both U937-control and U937-B27 exhibited a stereotypic response to LPS. Only one gene, OAS2, was differentially expressed by these cell lines, and this was confirmed by quantitative PCR. Analysis of XBP-1 splicing suggested that the UPR is induced following the LPS stimulation, but this increase was seen in all transfectants. CONCLUSIONS: The expression of B27 does not profoundly alter the gene expression following LPS stimulation. Therefore, additional signals, such as those provided by cytokines or intracellular infection, may be required to reveal any influence of B27 expression on the inflammatory response.

Gene Expression Profiling↗

PubMed2006

Epidemiology of pre-eclampsia and eclampsia at the KK Women's and Children's Hospital, Singapore.

INTRODUCTION: The incidences and characteristics of pre-eclampsia (PE) and eclampsia in KK Women's and Children's Hospital (KKH), a tertiary obstetrical referral centre in Singapore, were studied. METHODS: The incidences and types of PE between July 1999 and June 2003 were derived from the pregnancy disease databases. The characteristics of women with PE in relation to the general obstetric population were analysed on the age, race, parity, types of delivery, gestation at delivery and mortality. Case records of eclampsia were analysed. RESULTS: A total of 2,213 (3.6 percent) out of 61,595 deliveries were complicated by PE between July 1999 and June 2003. Incidence rates for mild or unspecified PE, severe PE, eclampsia and PE superimposed on hypertension were 2.47 percent (1,518), 0.97 percent (599), 0.02 percent (10) and 0.14 percent (85), respectively. The incidence increased with multiple pregnancies: from 3.5 percent in singletons to 7.5 percent in twins, 19.4 percent in triplets and 25.0 percent in quadruplets. The Caesarean section rate for PE was 46.1 percent compared with 23.7 percent in the hospital population. The proportion of premature birth (<37 weeks) in PE was 31.0 percent and that of severe prematurity (<32 weeks) was 5.7 percent, while hospital population proportions were 9.8 percent and 1.3 percent, respectively. The perinatal mortality rate (PMR) of PE was 11.0/1,000 births (population PMR was 4.4/1,000 births). There were only ten cases of eclampsia out of 61,595 deliveries (1:6160) giving an incidence of eclampsia of 16.2/100,000 deliveries. There was no stillbirth, neonatal and maternal death among the eclamptic patients. CONCLUSION: The incidence and outcome of eclampsia in KKH showed a significant reduction over the years due to improved obstetrical care. While PE is still common, eclampsia is now a very rare disease outcome.

Adult↗

PubMed2006

Recurrent neural tube defects.

We report a case of recurrent neural tube defects in a 30-year-old multigravida with no medical or family history of note. She presented with a significant history of having three (out of four) previous pregnancies affected by neural tube defects diagnosed at the 20-week foetal anomaly ultrasonographical scans, and which resulted in mid-trimester pregnancy terminations. Previous investigations for the foetuses did not yield any obvious cause. We discuss the possible differential diagnoses and aetiological factors. Rare causes of neural tube defects need to be excluded in recurrent cases with no obvious aetiology.

Adult↗

PubMed2005

The amniotic sheet: a truly benign condition?

OBJECTIVE: Amniotic sheets are the result of uterine synechiae that have been encompassed by the expanding chorion and amnion. Radiologically they are seen as 'shelves' in the amniotic cavity. The benign nature of such amniotic sheets has been documented in many case series in the literature. The objective of this study was to determine the characteristics (if any) of amniotic sheets that predict fetal outcome. METHODS: Between January 2001 and December 2002, detailed scans were performed in 30 476 singleton pregnancies at 18-32 weeks' gestation. Of these, 44 cases of amniotic sheets were detected. The characteristics studied were site of amniotic sheet and whether the amniotic sheet was complete (i.e. no free edge seen on ultrasound) or incomplete (i.e. presence of free edge seen on ultrasound). The primary fetal outcome studied was stillbirth. RESULTS: The incidence of amniotic sheets was 0.14%. Two were complete and 42 were incomplete. Of the 38 cases with known outcomes there were two intrauterine deaths. There was no association between fetal outcome and the uterine location of the amniotic sheet (i.e. upper two-thirds vs. lower third, P = 0.5). There was, however, an association between the completeness of the amniotic sheets and intrauterine death (P = 0.002). Both instances of intrauterine death occurred in the two cases with complete amniotic sheets. Postmortem examination suggested that cord accidents were the cause of intrauterine death in both cases. CONCLUSIONS: This study supports the view that incomplete amniotic sheets are benign. It also suggests for the first time that complete amniotic sheets may be associated with intrauterine death.

Adult↗

PubMed2005

Investigating stillbirths using a simplified obstetric events-based protocol.

INTRODUCTION: A stillbirth remains a distressing enigma to parents and clinicians alike as the cause often remains elusive. Few papers describe a protocol for the investigation of stillbirths. We evaluate the first obstetric events-based protocol designed for local use with an aim to adequately investigate stillbirths in a cost-effective manner. METHODS: A prospective cohort study was performed on 61 stillbirths at KK Women's and Children's Hospital. There were a total of 16,980 births in the year 2000. RESULTS: 37.7 percent of cases remained unexplained. There was protocol compliance in 51 cases (83.6 percent) with deviation in 10 cases (16.4 percent). The protocol helped to minimise costs in 18 cases (29.5 percent) as selected investigations were performed in view of obvious causes. The overall postmortem rate was 27.9 percent with the lowest rates in the Malay population. CONCLUSION: An obstetric events-based protocol allows clinicians to tailor their investigations easily and appropriately. It helps to provide optimal investigations and minimise unnecessary costs. It could be further fine-tuned by initiating detailed serum investigations only after delivery so as to exclude an obvious cause, like cord accidents, where full investigations are unnecessary.

Adult↗

PubMed2005

Outcomes of twin-twin transfusion syndrome managed by a specialised twin clinic.

INTRODUCTION: To determine the perinatal outcomes of monochorionic (MC) pregnancies complicated by the twin-twin transfusion syndrome (TTTS) that were managed in a specialised twin clinic at the KK Women's and Children's Hospital. METHODS: This was a 21-month retrospective study carried out from January 2002 to September 2003. MC pregnancies were followed up every two to three weeks with regular ultrasonographical and Doppler studies from the time monochorionicity was diagnosed. Standard criteria used for the diagnosis of TTTS are the presence of oligohydramnios/polyhydramnios sequence on ultrasonography. The severity of TTTS was staged according to Quintero's system. RESULTS: There were 77 sets of MC pregnancies in our database. 11 sets were diagnosed with TTTS, hence the incidence was 14.3 percent. The median gestation at diagnosis of TTTS was 17.4 (16.4 to 26) weeks. At first presentation, five were stage I, two were stage II, three were stage III and one was stage IV. Three pregnancies were terminated in the second trimester and one was lost to follow-up. Of the other seven, two were treated expectantly or delivered, four with amnioreduction/ septostomy and one with cord occlusion. The median gestation at delivery is 30.8 (26.7 to 36.9) weeks. Four (57 percent) were delivered before 32 weeks and these same four pairs required neonatal intensive care. The overall perinatal survival was 78 percent (11/14) and the median diagnosis to delivery interval was 10.7 (3.1 to 17.5) weeks. CONCLUSION: TTTS occurs in a significant proportion of MC pregnancies. The perinatal survival outcome of this group of patients managed in this clinic is comparable to that of other good centres.

Adult↗

PubMed2005

Birth defects in Singapore: 1994-2000.

INTRODUCTION: To study characteristics of birth defect cases among live births, stillbirths and abortions in Singapore between 1994 and 2000. METHODS: Index cases for the National Birth Defects Registry (NBDR) were obtained from all neonatal nurseries in Singapore, all hospital discharge summaries, cytogenetic and pathology reports from all pathology laboratories in Singapore, and from the compulsory reporting of all termination of pregnancy cases and stillbirths delivered. Further information was obtained from case notes retrieved from the medical record offices, antenatal clinics, cytogenetic laboratories, pathology departments and the Registry of Births and Deaths. The notified cases (live births, stillbirths and abortions) between 1994 and 2000 were extracted from the NBDR and analysed with regard to ethnicity, maternal age, trend over the seven years and types of birth defects using the British Paediatric Association Classification. RESULTS: Between 1994 and 2000, a total of 7,870 cases (6,278 births and 1,592 abortuses) were notified, giving a rate of 23.99 birth defect cases per 1000 live births. There was a decreasing trend in birth defect incidence (19.76 to 16.85 per 1,000 live births) among live births and stillbirths and an increasing trend of abortion (3.25 to 7.57 per 1,000 live births) for birth defects. Malays had a higher rate of congenital defects at birth (24.4/1,000 live births) compared to Chinese (18.4/1,000 births). The 25-29 years age group had the lowest overall rate (22.6/1,000 live births) compared to the 19 years and below group at 31.6/1,000 live births and the 45-49 years group at 126.6/1,000 live births. The five most common groups of anomalies (per 1,000 live births) were those of heart (9.07), musculoskeletal (4.98), chromosomal (4.35), urinary (3.12) and nervous systems (2.90). The five most common aborted anomalies (per 1,000 live births) were those of chromosomal (2.40), nervous (1.23), heart (0.95), musculoskeletal (0.85) and urinary systems (0.36). CONCLUSION: There was an increasing trend of abortion for birth defects, accompanied by a falling trend in the congenital anomalies of live births. Both extremes of maternal age were at higher risk of non-chromosomal birth defects while advanced maternal age was at higher risk of chromosomal defects.

Adolescent↗

PubMed2004

Mice lacking pro-opiomelanocortin are sensitive to high-fat feeding but respond normally to the acute anorectic effects of peptide-YY(3-36).

Inactivating mutations of the pro-opiomelanocortin (POMC) gene in both mice and humans leads to hyperphagia and obesity. To further examine the mechanisms whereby POMC-deficiency leads to disordered energy homeostasis, we have generated mice lacking all POMC-derived peptides. Consistent with a previously reported model, Pomc(-/-) mice were obese and hyperphagic. They also showed reduced resting oxygen consumption associated with lowered serum levels of thyroxine. Hypothalami from Pomc(-/-) mice showed markedly increased expression of melanin-concentrating hormone mRNA in the lateral hypothalamus, but expression of neuropeptide Y mRNA in the arcuate nucleus was not altered. Provision of a 45% fat diet increased energy intake and body weight in both Pomc(-/-) and Pomc(+/-) mice. The effects of leptin on food intake and body weight were blunted in obese Pomc(-/-) mice whereas nonobese Pomc(-/-) mice were sensitive to leptin. Surprisingly, we found that Pomc(-/-) mice maintained their acute anorectic response to peptide-YY(3-36) (PYY(3-36)). However, 7 days of PYY(3-36) administration had no effect on cumulative food intake or body weight in wild-type or Pomc(-/-) mice. Thus, POMC peptides seem to be necessary for the normal response of energy balance to high-fat feeding, but not for the acute anorectic effect of PYY(3-36) or full effects of leptin on feeding. The finding that the loss of only one copy of the Pomc gene is sufficient to render mice susceptible to the effects of high fat feeding emphasizes the potential importance of this locus as a site for gene-environment interactions predisposing to obesity.

Animals↗

PubMed2004

Antenatal use of a novel vaginal birth training device by term primiparous women in Singapore.

INTRODUCTION: To study the use, safety and effectiveness of a novel antenatal vaginal birth training device (EPI-NO) in primiparous women. METHODS: Antenatal use of the EPI-NO vaginal birth trainer was prospectively studied in 31 primiparous booked patients who were delivered by obstetricians from July to December 2002 at the KK Women's and Children's Hospital. This was studied in relation to episiotomy rate, perineal trauma and analgesic requirements during the postpartum period. A patient questionnaire form was used to assess their perception of pain and how well they coped with its use. For comparison, perineal trauma was also studied retrospectively in 60 consecutive obstetrician-booked primiparous term patients who had normal vaginal delivery (NVD) and who did not use EPI-NO during the same study period. RESULTS: The mean length of usage was for 2.1 weeks (standard deviation [sd] 1.2 weeks). The mean frequency of use was 5.3 episodes per week (sd 2.1, range 1 to 7). There was no laceration and vaginal infection arising from its usage. There was a case of minimal bleeding post-usage. There were 20 (64.5 percent) NVDs, four (12.9 percent) forceps deliveries, five vacuum deliveries (16.1 percent) and two (6.5 percent) Caesarean sections. Of the 29 vaginal delivery cases, 19 (65.5 percent) had episiotomy, eight (27.6 percent) had lacerations, and two (6.9 percent) did not sustain laceration. The reasons for episiotomy in the 19 cases were nine cases of pending tearing of vagina/perineum, nine cases of instrumental vaginal deliveries, and one to shorten second stage. There was no third degree tear. 21 (67.7 percent) out of 30 required a painkiller. The majority of patients (17; 54.8 percent) appeared to be comfortable with the use of EPI-NO. All coped well with vaginal examination after using EPI-NO perineal training. Comparing among term primiparous NVD cases with (n value equals 20) and without (n value equals 60) EPI-NO, the perineal trauma rate (90.0 percent vs 96.6 percent, p value equals 0.24) was slightly but not significantly lower in the EPI-NO group. The episiotomy rate was significantly lower (50.0 percent vs 93.3 percent, p value is less than 0.0001) and the extent of perineal trauma in the patient appeared to be less severe in cases using EPI-NO. CONCLUSION: EPI-NO appeared to be safe and acceptable to the majority of users. Although birth training with EPI-NO significantly decreases the rate of episiotomies in term primiparous patients, and the degree of perineal tissue injury appeared to be less in the EPI-NO group especially among those with lacerations, the overall perineal trauma rate was slightly but not significantly lower, in view of the higher spontaneous laceration rate in the EPI-NO group.

Analgesics↗

PubMed2004

Assessment of maternal anxiety levels before and after amniocentesis.

INTRODUCTION: To assess anxiety levels in mothers before and after undergoing amniocentesis. The secondary aim was to see how counselling by nurse-counsellors affected maternal anxiety levels. METHODS: A prospective study was carried out from February 2000 to August 2000 at the Kandang Kerbau Women's and Children's Hospital in Singapore. We used standard statistical analysis and Spielberger's state-trait anxiety inventory (STAI), that consisted of 40 items, to assess anxiety levels. Anxiety levels were assessed at different stages: before and after counselling; before amniocentesis and after amniocentesis; when results were disclosed; and after the routine 20-week screening ultrasound scan was acknowledged four to six weeks later. English-speaking women were recruited for the study as the STAI questionnaire has only been validated for an English-speaking population. 195 at-risk mothers (advanced maternal age, abnormal nuchal translucency on ultrasound scan, previous abnormal baby and high-risk maternal serum screening results) and patients requesting for amniocentesis between 15 to 20 weeks gestation were recruited. RESULTS: 156 mothers agreed to amniocentesis. 38 mothers declined amniocentesis. S-anxiety levels declined significantly after counselling by trained nurse-counsellors in all mothers counselled. S-anxiety levels were highest and significantly higher compared to all other times just prior to amniocentesis despite counselling. Anxiety levels were the lowest and significantly lower compared to all other times at the last assessment stage. CONCLUSION: High level of anxiety prior to amniocentesis despite counselling is understandable due to the invasive nature of the procedure. There is no long-lasting post-procedural anxiety to the mother.

Adult↗

PubMed2004

Does maternal serum screening for Down syndrome induce anxiety in younger mothers?

INTRODUCTION: To assess anxiety levels in mothers with low-risk pregnancies before and after offering routine serum screening. METHODS: A prospective study was carried out at the Kandang Kerbau Women's and Children's Hospital in Singapore from February 2000 to August 2000. We used standard statistical analysis and Spielberger's state-trait anxiety inventory (STAI) which consists of 40 items to assess anxiety. Anxiety levels were assessed at several stages: before serum screening counselling, after counselling but before serum screening, before the routine 20-week obstetrical screening ultrasound scan, and after ultrasound scan results were acknowledged four to six weeks later. As the STAI questionnaire has only been validated for an English-speaking population, only English-speaking women were recruited for the study. The subjects included 111 women between 15 to 20 weeks gestation that were randomly selected (without any risk factors) for serum screening counselling. RESULTS: Anxiety levels did not decline significantly after counselling by a trained nurse-counsellor. They were highest prior to counselling and were significantly higher compared to all other times in which anxiety was assessed. Anxiety levels were lowest after the serum screening and routine 20-week screening ultrasound scan results were acknowledged. They were also significantly lower compared to all other times in which anxiety was assessed. CONCLUSION: Anxiety before serum screening was not abnormally high and routine serum screening offered by trained nurse counsellors did not significantly increase maternal anxiety in mothers with low risk pregnancies.

Adult↗

PubMed2003

Our experience with eclampsia in Singapore.

AIM: To assess the incidence, epidemiological factors, preceding symptoms and signs, management regimens and obstetric outcomes of eclampsia in a tertiary care hospital in Singapore. METHOD: A retrospective study of all obstetric patients who suffered one or more eclamptic seizures in our hospital between January 1994 and December 1999. RESULT: There were 62 cases of eclampsia among 92,305 deliveries (6.7 per 10,000 deliveries). The incidence was highest among Indians. Those aged between 25 and 34 had the lowest incidence, while women younger than 25 or older than 34 had a significantly higher incidence. Forty (64.5%) patients had symptom or sign of impending eclampsia of which headache was the most common. Most of the patients (81.6%) who received antenatal care with us suffered their first eclamptic seizure in hospital, compared to 50% of the unbooked patients. There was one maternal death (mortality rate 1.6%), and 15 (24.2%) women had significant morbidity. There were 61 singleton pregnancies and one twin pregnancy. There were six intrauterine deaths and 57 livebirths. The perinatal mortality rate was 95.2 per 1,000 births. CONCLUSION: Eclampsia is still a major cause of maternal and foetal mortality and morbidity in Singapore. Race and age appear to be risk factors for eclampsia with Indian women and those at the extremes of reproductive age at greater risk. Antenatal care is important in reducing perinatal mortality and possibly maternal complications.

Adolescent↗

PubMed2003

Foetal intralobar lung sequestration: antenatal diagnosis and management.

OBJECTIVES: The objectives of this study are to discuss the use of ultrasonography for the diagnosis of foetal intralobar sequestration (FILS) antenatally and the management options available for these pregnancies. METHODS: This is a retrospective review of six cases of FILS diagnosed antenatally by two dimensional (2D) and colour Doppler ultrasonography out of a total of 31,508 deliveries over a two-year period at the KK Women's and Children's Hospital. RESULTS: The incidence of FILS in this hospital was 1 in 5,251 deliveries. 2D ultrasonography showed an echogenic lung in all cases. FILS was confirmed by the demonstration of a systemic vessel leading to the affected lung on colour Doppler examination. After counselling, four terminated their pregnancies during mid-trimester, while two continued their pregnancies to term. Confirmation of the terminated cases was by post-mortem. In the two pregnancies that continued, regular growth scans were done to monitor the progression of the condition. Computed tomography confirmed the diagnosis post-delivery. Both were well but one had a resection of the sequestrated lung although he was asymptomatic. Histology also confirmed the diagnosis. CONCLUSION: FILS is a rare anomaly. 2D and colour Doppler ultrasonography are used to diagnose the condition antenatally. Termination of the pregnancy is not always indicated, as there are favourable outcomes from FILS.

Adult↗

PubMed2002

Birth prevalence of Down syndrome in Singapore from 1993 to 1998.

OBJECTIVE: To examine the livebirth prevalence rate of Down Syndrome in Singapore from 1993 to 1998. DESIGN: Index cases for the National Birth Defects Register were obtained from all neonatal nurseries in Singapore, all hospital discharge summaries, cytogenetic and pathology reports from all pathology laboratories in Singapore and from the compulsory reporting of all termination of pregnancy cases and stillbirths delivered. SETTING: Information for the Register was obtained from case notes retrieved from the medical record offices, antenatal clinics, cytogenetic laboratories, pathology departments and the Registry of Births and Deaths. SUBJECTS: All foetuses with Trisomy 21 diagnosed prenatally together with livebirths and stillbirths with Down Syndrome diagnosed at or after birth were identified from the Registry database. MAIN OUTCOME MEASURES: Prevalence of Down Syndrome RESULTS: From 1993 to 1998, there were 295 Down Syndrome livebirths, four stillbirths and 197 Down Syndrome foetuses aborted. There has been an increasing number of Down Syndrome foetuses diagnosed antenatally ending in termination and this is accompanied by a falling trend in the Down Syndrome livebirth rate in the same years from 1.17 to 0.89 per 1000 total live births. This is despite an expected increase in Down Syndrome livebirth rate obtained by modelling maternal Down Syndrome age-related risks on the maternal age distribution over the years. CONCLUSIONS: The livebirth prevalence of Down Syndrome in Singapore has fallen over the years from 1.17/1000 livebirths in 1993 to 0.89/1000 livebirths in 1998 due to antenatal diagnosis and selective termination.

Abortion, Induced↗

PubMed2002

Current understanding of pre-eclampsia.

INTRODUCTION: Pre-eclampsia is associated with significant morbidity and mortality for mother and baby, with post partum resolution. The disorder is triggered by a placental pathology followed by a wide spectrum of maternal systemic response. However, there remains controversy in practically every aspect of the condition. METHODS: A Medline search and hand search of recent publications pertaining to the scientific basis and clinical management of pre-eclampsia. RESULTS: With current interest in the scientific and molecular basis of the disease process, there has been an improved, albeit incomplete, understanding of the precise aetiology and pathogenesis of pre-eclampsia. Much of this has translated to improved clinical management strategies. The more rational use of various pharmacological agents, timing the delivery to optimise both the maternal and fetal condition, the decreasing rate of eclampsia, as well as trials on various screening and prophylactic strategies are testimony to this improvement. Despite this, many unanswered questions still remain and provide a challenge for both the clinician as well as the researcher. CONCLUSIONS: We reviewed the recent literature in order to provide a contemporary understanding of the basic pathogenesis of the condition as well as to highlight some basic strategies for clinical management. There is a clear need for more research to better understand the basic science behind the genesis of this condition, as well as to improve the level of care we offer to these women through the co-ordination of a multi-disciplinary team of clinicians.

Anticoagulants↗