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Biomedical subjects

S H Lim

Publications and source records attributed to S H Lim.

At least 19 recordsLinked to original sources
PubMed2003

Indications of neutrino oscillation in a 250 km long-baseline experiment.

The K2K experiment observes indications of neutrino oscillation: a reduction of nu(mu) flux together with a distortion of the energy spectrum. Fifty-six beam neutrino events are observed in Super-Kamiokande (SK), 250 km from the neutrino production point, with an expectation of 80.1(+6.2)(-5.4). Twenty-nine one ring mu-like events are used to reconstruct the neutrino energy spectrum, which is better matched to the expected spectrum with neutrino oscillation than without. The probability that the observed flux at SK is explained by statistical fluctuation without neutrino oscillation is less than 1%.

Journal Article↗
PubMed2003

Traumatic atypical Brown-Sequard syndrome: case report and literature review.

A man was kicked on the neck, 10 days after which he noted right-sided numbness. Clinically, he had diminished deep tendon reflexes over the left upper limb, absent left superficial abdominal reflexes, a left extensor plantar response, mild left hemiparesis, diminished pinprick, temperature and vibratory sensation up to the right T(4-5) dermatome and diminished proprioceptive sensation in the right upper and lower limbs. Cervicothoracic magnetic resonance imaging (MRI) revealed a left C(6-7) posterolateral disc prolapse with indentation and oedema of the cord at the same level. He was given intravenous dexamethasone, with mild resolution of his motor but not his sensory symptoms. Transcranial magnetic stimulation and evoked potentials performed 3 days later were unremarkable. He was discharged soon after, preferring to seek traditional therapy in his country. We attempt to explain the anatomical basis for his clinical signs, review the literature for similar cases, and examine the usefulness of available treatment and investigations.

Adult↗
PubMed2002

Slow-infusion of calcium channel blockers in the emergency management of supraventricular tachycardia.

OBJECTIVE: To compare the efficacy of verapamil and diltiazem as slow infusions in terminating spontaneous supraventricular tachycardia (SVT) in the emergency department (ED). METHOD: Patients of at least 10 years of age who presented to our ED with regular narrow complex tachycardia not converted with a vagal manoeuvre with an ECG diagnosis of SVT were included. Those who were haemodynamically unstable were excluded. Patients were randomized to undergo either verapamil infusion at a rate of 1 mg/min to a maximum of 20 mg or diltiazem infusion at a rate of 2.5 mg/min to a maximum of 50 mg. RESULTS: Eighty-one patients were randomized to receive verapamil infusion and 80 were randomized to receive the diltiazem infusion. There is no difference in success rate between verapamil (98.8%) and diltiazem (96.3%) infusion. The dose of medication required to convert 25,50 and 75% of SVTs were 4.0,5.0 and 8.0 mg for the verapamil infusion and 10.0,12.5 and 17.5 mg for the diltiazem infusion. There was one complication in each group. CONCLUSION: Calcium channel blockers infusions were safe and efficacious in terminating spontaneous SVT. There was no difference between the success rates of verapamil and diltiazem infusions.

Calcium Channel Blockers↗
PubMed2002

Successful generation of sperm protein 17 (Sp17)-specific cytotoxic T lymphocytes from normal donors: implication for tumour-specific adoptive immunotherapy following allogeneic stem cell transplantation for Sp17-positive multiple myeloma.

Sperm protein 17 (Sp17) is a highly immunogenic cancer-testis antigen expressed by tumour cells from up to 30% of patients with multiple myeloma (MM). We recently successfully generated Sp17-specific human leucocyte antigen (HLA)-A1 and B27-restricted cytotoxic T lymphocytes (CTLs) from the peripheral blood of a healthy donor. Because CTLs were able to kill HLA-matched fresh myeloma cells, it may be possible to generate and administer myeloma-specific donor T cells to MM patients following allogeneic stem cell transplantation to enhance graft-versus-myeloma (GVM) without inducing graft-versus-host disease (GVHD). To determine how widely applicable this approach is, we have determined the ability to generate Sp17-specific CTLs from four consecutive healthy donors with other HLA class I phenotypes. We found that Sp17-specific HLA class I-restricted CTLs could be easily generated from all four donors. Sp17-specific CTLs were primarily CD8 in phenotype and produced interferon-gamma and very little interleukin-4. These T cells killed target cells primarily via the perforin-mediated route. These results therefore suggest that myeloma-specific donor T-cell infusion that targets Sp17 to selectively enhance GVM could be applicable to patients with Sp17+ MM.

Adult↗
PubMed2002

A randomized controlled trial comparing the hair apposition technique with tissue glue to standard suturing in scalp lacerations (HAT study).

STUDY OBJECTIVE: We evaluate a new technique of treating scalp lacerations, the hair apposition technique (HAT). After standard cleaning procedures, hair on both sides of a laceration is apposed with a single twist. This is then held with tissue adhesives. HAT was compared with standard suturing in a multicenter, randomized, prospective trial. METHODS: All linear lacerations of the scalp less than 10 cm long were included. Severely contaminated wounds, actively bleeding wounds, patients with hair strand length less than 3 cm, and hemodynamically unstable patients were excluded. Patients were randomized to receive either HAT or standard suturing, and the time to complete the wound repair was measured. All wounds were evaluated 7 days later in a nonblinded manner for satisfactory wound healing, scarring, and complications. RESULTS: There were 96 and 93 patients in the study and control groups, respectively. Wound healing trended toward being judged more satisfactory in the HAT group than standard suturing (100% versus 95.7%; P =.057; effect size 4.3%; 95% confidence interval 0.1% to 8.5%). Patients who underwent HAT had less scarring (6.3% versus 20.4%; P =.005), fewer overall complications (7.3% versus 21.5%; P =.005), significantly lower pain scores (median 2 versus 4; P <.001), and shorter procedure times (median 5 versus 15 minutes; P <.001). There was a trend toward less wound breakdown in the HAT group (0% versus 4.3%; P =.057). When patients were asked whether they were willing to have HAT performed in the future, 84% responded yes, 1% responded no, and 15% were unsure. CONCLUSION: HAT is equally acceptable and perhaps superior to standard suturing for closing suitable scalp lacerations. Advantages include fewer complications, a shorter procedure time, less pain, no need for shaving or removal of stitches, similar or superior wound healing, and high patient acceptance. HAT has become our technique of choice for suitable scalp lacerations.[Ong Eng Hock M, Ooi SBS, Saw SM, Lim SH. A randomized controlled trial comparing the hair apposition technique with tissue glue to standard suturing in scalp lacerations (HAT study).

Adolescent↗
PubMed2002

Acute coronary syndrome--factors causing delayed presentation at the Emergency Department.

INTRODUCTION: The aim of the study was to identify factors that contributed to delays in presentation of patients with acute coronary syndrome (ACS) at the Emergency Department (ED). MATERIALS AND METHODS: The study population comprised patients presenting with the signs and symptoms of ACS at the ED of 5 government and restructured hospitals in Singapore from 1 April to 31 May 1999. These patients were interviewed with a structured questionnaire which explored patient demographic data, risk factors, prehospital symptomatology, timing of chest pain, patient response to chest pain and mode of transport to the hospital. RESULTS: Three hundred and two patients who made 307 visits were recruited. More than three-quarters of the patients presented with central or left-sided chest pain. Forty-seven per cent had breathlessness and 42% had sweating. The commonest day of presentation was Monday. It took patients a median time of 2.1 hours from their worst chest pain to arrive at the ED. Past history of diabetes mellitus was associated with a longer delay in presentation. Most of the delay was due to patients awaiting symptom resolution. Forty per cent came by emergency ambulances to hospital. CONCLUSION: Our findings identified various patient characteristics that contributed to delay in presentation to hospital which should be addressed in future education campaigns.

Adult↗
PubMed2002

Intravenous adrenaline or vasopressin in sudden cardiac arrest: a literature review.

INTRODUCTION: The chain of survival concept implies that provision of early access, early advanced care, including early intravenous drugs would improve survival in sudden cardiac arrest. Intravenous adrenaline (epinephrine) has been used as the drug of choice since 1906. What is the evidence for its effectiveness? Is vasopressin a better alternative? METHODS: We performed a systematic literature search in order to answer these questions. Evidence from the clinical trials that have been conducted on this subject was reviewed. RESULTS: Experimental evidence confirms the beneficial effect adrenaline has on coronary perfusion pressure. However, adrenaline has not been shown conclusively to improve survival in clinical trials. Extensive trials have also failed to show any benefit of high-dose adrenaline over standard doses. Vasopressin seems to be more effective than adrenaline in animal studies for treatment of cardiac arrest due to resistant ventricular fibrillation. However, it has yet to be proven to be superior to adrenaline in clinical trials. CONCLUSION: More research is needed into this area, especially randomised controlled trials studying the effectiveness of vasopressin. Meanwhile, in order to improve survival from sudden cardiac arrest, continuing effort should be made to achieve early initiation of cardiopulmonary resuscitation, early defibrillation and early advanced care.

Critical Care↗
PubMed2001

Heart rate changes during partial seizures: a study amongst Singaporean patients.

INTRODUCTION: Studies in Europe and America showed that tachycardia, less often bradycardia, frequently accompanied partial seizures in Caucasian patients. We determine frequency, magnitude and type of ictal heart rate changes during partial seizures in non-Caucasian patients in Singapore. METHODS: Partial seizures recorded during routine EEGs performed in a tertiary hospital between 1995 and 1999 were retrospectively reviewed. All routine EEGs had simultaneous ECG recording. Heart rate before and during seizures was determined and correlated with epileptogenic focus. Differences in heart rate before and during seizures were grouped into 4 types: (1) >10% decrease; (2) -10 to +20% change; (3) 20-50% increase; (3) >50% increase. RESULTS: Of the total of 37 partial seizures, 18 were left hemisphere (LH), 13 were right hemisphere (RH) and 6 were bilateral (BL) in onset. 51% of all seizures showed no significant change in heart rate (type 2), 22% had moderate sinus tachycardia (type 3), 11% showed severe sinus tachycardia (type 4), while 16% had sinus bradycardia (type 1). Asystole was recorded in one seizure. Apart from having more tachycardia in bilateral onset seizures, there was no correlation between side of ictal discharge and heart rate response. Compared to Caucasian patients, sinus tachycardia was considerably less frequent. Frequency of bradycardia was similar to those recorded in the literature. CONCLUSIONS: Significant heart rate changes during partial seizures were seen in half of Singaporean patients. Although sinus tachycardia was the most common heart rate change, the frequency was considerably lower compared to Caucasian patients. This might be due to methodological and ethnic differences. Rates of bradycardia are similar to those recorded in the literature.

Adolescent↗
PubMed2001

New source of stacking faults in heteroepitaxial systems.

A new stacking fault formation mechanism has been observed for the first time in ZnO/LiTaO(3) heteroepitaxial films. High resolution electron microscopy studies combined with electron diffraction and numerical image computation suggest that the observed type I1 intrinsic stacking faults in an epitaxial film can be dominantly formed as a result of tilting of the lattices between films and substrate required to maintain a particular orientation relationship.

Journal Article↗
PubMed2001

Asymmetric syntheses of fused bicyclic compounds by conjugate additions of allylic organolithium species to activated olefins and subsequent cyclizations.

[reaction: see text]. Addition of the configurationally stable organolithium species produced by enantioselective deprotonation of N-Boc-N-(p-methoxyphenyl) allylamines to alpha,beta-unsaturated carbonyl compounds affords 1,4-addition products in good yields with high diastereomeric and enantiomeric ratios. Further transformations of these compounds provide [3.3.0]-, [4.3.0]-, [5.3.0]-, and [5.4.0]-carbocycles and heterocycles with high stereoselectivities.

Alkenes↗
PubMed2001

Sperm protein 17 is a novel cancer-testis antigen in multiple myeloma.

Various studies have demonstrated the aberrant expression of normal testicular proteins in neoplastic cells. These proteins collectively form the new class of tumor antigens called cancer-testis (CT) antigens. Their selective normal tissue expression makes them ideal antigens for immune targeting of the malignant disease. In this study, the expression of a spermatozoa protein, Sp17, in multiple myeloma was investigated. It was found that Sp17 is detectable in tumor cells from 12 of 47 (26%) myeloma patients. Reverse transcription polymerase chain reaction (RT-PCR) and Western blot analysis detected Sp17 transcripts and proteins, respectively. Northern blot analysis and RT-PCR demonstrated that Sp17 transcripts were detected only in normal testis, supporting its tissue specificity. Since a high proportion of normal individuals develop antibodies against Sp17 following vasectomy, Sp17 is likely to be a highly immunogenic protein in vivo. Sp17 is therefore a novel member of the CT antigen family and should be an ideal target for immunotherapy of multiple myeloma.

Antigens, Neoplasm↗
PubMed2001

Distinct T-cell clonal expansion in the vicinity of tumor cells in plasmacytoma.

BACKGROUND: Although various clinical observations suggested that myeloma cell growth might be modulated by the immune system, evidence supporting the in situ immunogenicity of myeloma cells remains scarce. The authors reasoned that if there is any specific T-cell/tumor cell interaction in myeloma, it is most likely reflected in the T-cell population in the vicinity of the tumor cells. METHODS: The authors used a molecular method to compare the T-cell populations in the vicinity of tumor cells with those in the peripheral blood in patients with plasmacytomas and multiple myeloma. RESULTS: Six patients were studied. When compared with the peripheral blood from the corresponding patients, T cells in the vicinity of tumor cells in five of the six patients showed significant contraction of the T-cell receptor (TCR) Vbeta repertoire. In addition to this, the T cells isolated from the sites of the tumor cells from four of these five patients also demonstrated significant increase in the number of TCR Vbeta gene families with restricted number of CDR3 size peaks and loss of the normal CDR3 size gaussian distribution pattern. These findings were observed in patients who experienced recurrence after allogeneic stem cell transplantation and also in those who had autologous stem cell transplant. They also were found in previously untreated myeloma patients. In all six patients, distinct TCR Vbeta recurring transcripts indicative of a T-cell clonal expansion were found in the vicinity of the tumor cells and either absent or detected at only a low frequency in the peripheral blood. CONCLUSIONS: Our results provide evidence for an in situ local T-cell clonal expansion in the vicinity of tumor cells and support the presence of specific T-cell/tumor cell interaction in myeloma.

Adult↗
PubMed2001

Sperm protein 17 (Sp17) in multiple myeloma: opportunity for myeloma-specific donor T cell infusion to enhance graft-versus-myeloma effect without increasing graft-versus-host disease risk.

We recently found that sperm protein 17 (Sp17), a spermatozoa-restricted protein, is aberrantly expressed on the tumor cells in patients with multiple myeloma (MM). It may therefore be possible to generate donor-derived Sp17-specific CTL for administration following allogeneic stem cell transplant to augment graft-versus-myeloma (GVM) effect without inducing a global GVHD. To assess this approach, we have produced recombinant Sp17 protein and used Sp17 protein-pulsed dendritic cells to generate HLA class I-restricted Sp17-specific CTL from a previously unimmunized healthy donor. These CTL were able to lyse autologous Epstein-Barr virus-transformed lymphoblastoid cells in a Sp17-dependent manner. Target lysis was HLA-A1 and HLA-B27 restricted. Cytotoxicity could be blocked by antibodies against monomorphic HLA class I, HLA-A1 and HLA-B27 molecules but not HLA class II molecules. Most importantly, the CTL lysed HLA class I-matched Sp17-positive tumor cells, suggesting that Sp17 is processed and presented in association with the HLA class I molecules in Sp17-positive tumor cells in a concentration and configuration that could be recognized by recombinant protein-primed CTL. Analysis by flow cytometry of the CTL indicated that they were predominantly CD8 in phenotype and they produced IFN-gamma and very little IL-4. Our results suggest the potential for the generation and administration of donor-derived Sp17-specific CTL to augment GVM without inducing GVHD following allogeneic stem cell transplant for MM.

Antigen Presentation↗
PubMed2001

Pain after laparoscopic cholecystectomy: the effect and timing of incisional and intraperitoneal bupivacaine.

PURPOSE: To examine the combined preemptive effects of somatovisceral blockade during laparoscopic cholecystectomy (LC). METHODS: One hundred fifty-seven patients under general anesthesia receiving local infiltration and/or topical peritoneal local anesthesia were studied. Patients were randomized to receive a total of 150 mg (0.25% 60 mL) bupivacaine via periportal (20 mL) and intraperitoneal (40 mL with 1:200,000 epinephrine) administration of each. Group A received preoperative periportal bupivacaine before incision and intraperitoneal bupivacaine immediately after the pneumoperitoneum. Group B received periportal and intraperitoneal bupivacaine at the end of the operation. Group C (preoperative) and Group D (postoperative) received only periportal bupivacaine and Group E (preoperative) and Group F (post-operative) received only intraperitoneal bupivacaine. The control group received no treatment. Pain and nausea were recorded at one, two, three, six, nine, 12, 24, 36, and 48 hr postoperatively. RESULTS: Throughout the postoperative 48 hr, incisional somatic pain dominated over other pain localizations in the control group (P <0.05). The incisional pain of groups A, B, C and D was significantly lower than that of the control group in the first and second hours. The incisional pain of groups A and C was significantly lower than that of the control group in the first three hours. CONCLUSION: Incisional pain dominated during the first two post-operative days after LC. Preoperative somato-visceral or somatic local anesthesia reduced incisional pain during the first three post-operative hours. A combination of somato-visceral local anesthetic treatment did not reduce intraabdominal pain, shoulder pain or nausea more than somatic treatment alone. Preoperative incisional infiltration of local anesthetics is recommended.

Adult↗
PubMed2001

Accuracy of bedside clinical methods compared with fiberoptic endoscopic examination of swallowing (FEES) in determining the risk of aspiration in acute stroke patients.

This prospective study was undertaken to determine the accuracy of bedside clinical methods compared with fiberoptic endoscopic examination of swallowing (FEES) for detecting aspiration in acute stroke patients. Fifty patients underwent an examination of their ability to swallow 50 ml of water in 10-ml aliquots. Later their oxygen saturation levels before and after swallowing 10 ml of water were measured using a pulse oximeter. Oxygen desaturation of more than 2%, was considered to be clinically significant. All patients then underwent a FEES assessment by a speech therapist and were followed up during their inpatient stay for evidence of aspiration pneumonia. The oxygen desaturation test had a sensitivity of 76.9% and specificity of 83.3% (chi2 = 18.154, p = 0.00002), while the 50-ml water swallow test had a sensitivity of 84.6% and specificity of 75.0% (chi2 = 18.001, p = 0.00002). However, when these two tests were combined into one test called "bedside aspiration," the sensitivity rose to 100% with a specificity of 70.8% (chi2 = 27.9, p = 0.000001). Five (10%) patients developed pneumonia during their inpatient stay. The relative risk (RR) of developing pneumonia, if there was evidence of aspiration on FEES, was 1.24 (1.03 < RR < 1.49). We conclude that the oxygen desaturation test combined with the 50-ml water swallow test is suitable as a screening test to identify all acute stroke patients at risk of aspiration for further evaluation and management.

Acute Disease↗
PubMed2001

Mass cardiopulmonary resuscitation 99--survey results of a multi-organisational effort in public education in cardiopulmonary resuscitation.

Mass cardiopulmonary resuscitation (CPR) 99 in Singapore was a large-scale multi-organisational effort to increase awareness and impart basic cardiac life support skills to the lay public. Mass CPR demonstrations followed by small group manikin practice with instructor guidance was conducted simultaneously in three centres, four times a day. The exercise enlisted 15 community organisations and received the support of 19 other organisations. Three hundred and ninety-eight manikins and 500 instructors ('I's) were mobilised to teach an audience of 6000 participants ('P's). Two surveys, for 'I's and 'P's were conducted with respondent rates of 65.8% and 50%, respectively. 73.6% of the P-respondents ('P-R's) indicated that they attended the event to increase their knowledge. 66.9% were willing to attend a more comprehensive CPR course. Concerns and perceptions in performing bystander CPR were assessed.

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