PubMed Health⌕ Search

Biomedical subjects

A Wee

Publications and source records attributed to A Wee.

At least 19 recordsLinked to original sources
PubMed2006

Learnability and discriminability of melodic medical equipment alarms.

Melodic alarms proposed in the IEC 60601-1-8 standard for medical electrical equipment were tested for learnability and discriminability. Thirty-three non-anaesthetist participants learned the alarms over two sessions of practice, with or without mnemonics suggested in the standard. Fewer than 30% of participants could identify the alarms with 100% accuracy at the end of practice. Confusions persisted between pairs of alarms, especially if mnemonics were used during learning (p = 0.011). Participants responded faster (p < 0.00001) and more accurately (p = 0.002) to medium priority alarms than to high priority alarms, even though they rated the high priority alarms as sounding more urgent (p < 0.00001). Participants with at least 1 year of formal musical training identified the alarms more accurately (p = 0.0002) than musically untrained participants, and found the task easier overall (p < 0.00001). More intensive studies of the IEC 60601-1-8 alarms are needed for their effectiveness to be determined.

Adult↗
PubMed2006

Postinfectious gastroparesis related to autonomic failure: a case report.

BACKGROUND AND AIM: Severe dysautonomia may be secondary to viral infections, resulting in impaired autoimmune, cardiovascular, urinary and digestive dysfunction. Herein, we present a case of a 31-year-old white female patient who had severe gastroparesis related to autonomic failure following an episode of acute gastroenteritis. This seems to be the first report providing thorough assessment of the enteric and autonomic nervous system by analysis of full-thickness small intestinal biopsies, cardiovagal testing and autopsy. HOSPITAL COURSE: This patient affected by a severe gastroparesis was treated with antiemetics, prokinetics, analgesics and gastric electrical stimulation to control symptoms. Nutritional support was made using jejunal feeding tube and, in the final stage of disease, with total parenteral nutrition. Autonomic studies revealed minimal heart rate variability and a disordered Valsalva manoeuvre although the enteric nervous system and the smooth muscle layer showed a normal appearance. Hospital courses were complicated by episodes of bacteraemia and fungemia. Serum antiphospholipid antibodies were noted but despite anticoagulation, she developed a pulmonary embolism and shortly thereafter the patient died. Autopsy revealed acute haemorrhagic Candida pneumonia with left main pulmonary artery thrombus. Sympathetic chain analysis revealed decreased myelinated axons with vacuolar degeneration and patchy inflammation consistent with Guillain-Barre syndrome. The evaluation of the enteric nervous system in the stomach and small bowel revealed no evidence of enteric neuropathy or myopathy. CONCLUSION: A Guillain-Barre-like disease with gastroparesis following acute gastroenteritis is supported by physiological and autonomic studies with histological findings.

Adult↗
PubMed2006

Liver transplantation for hepatocellular carcinoma in Singapore.

INTRODUCTION: The prognosis of patients with hepatocellular carcinoma (HCC) is poor. Surgical resection offers the benefit of removal of the tumour but is associated with liver decompensation and tumour recurrence, even after successful surgery. Liver transplantation offers the benefits of complete tumour removal with prevention of both decompensation and recurrence post-operation. This paper aims to review results of liver transplantation for patients with HCC in Singapore. METHODS: All adult patients with HCC accepted on the waiting list for liver transplantation (based on the Milan criteria) from 1996 to 2004 in Singapore were reviewed. Patients' HCC were managed with either transarterial chemoembolisation or percutaneous radiofrequency ablation while they were on the waiting list. Post-transplant survival and factors associated with mortality were analysed by Cox regression analysis. RESULTS: 41 patients with HCC were accepted onto the waiting list over the nine-year period. 22 underwent transplantation and 19 did not, with a one-year survival of 91 percent versus 24 percent, respectively. (p-value is less than 0.001). Mean waiting time for transplant was 39 weeks. Post-transplant HCC recurrence was 2/22 (nine percent). Among all patients, mortality was significantly related to baseline white cell counts, prothrombin time, age, alpha-foetoprotein level, Child-Pugh score, and whether patients underwent transplant. CONCLUSION: Despite the relatively long waiting time of a mean of 39 weeks, post-transplant recurrence of HCC was relatively low at nine percent. Liver transplant is an effective treatment for patients with a HCC, with a reasonable long-term survival.

Carcinoma, Hepatocellular↗
PubMed2006

Long-term results of liver transplant in patients with chronic viral hepatitis-related liver disease in Singapore.

INTRODUCTION: Liver disease from chronic hepatitis B (CHB) and C (CHC) constitutes 57 percent of adult liver transplant in Singapore. Their long-term results post-transplant may be affected by recurrence of the viral illness. This study aims to evaluate the long-term results and survival in patients transplanted for CHB- and CHC-related liver disease. METHODS: Patients transplanted for CHB- and CHC-related disease from 1990 until March 2004, which included decompensated cirrhosis and hepatocellular carcinoma (HCC), were reviewed and analysed. RESULTS: 25 patients were transplanted for CHB-related liver disease, with mean follow-up of 153 +/- 25 weeks. Two- and four-year survival rates were 75 percent and 69 percent, respectively. Hepatitis B recurrence from YMDD mutants occurred in five patients, and four were treated successfully with adefovir dipivoxil, with resolution in transaminases and/or improvement in histology. One patient became non-compliant with follow-up and medications, and died 173 weeks post-transplant from reactivation of the wild-type hepatitis B virus. Nine patients were transplanted for CHC-related liver disease, with mean follow-up of 188 +/- 40 weeks, and two- and four-year survival rates of 89 percent and 76 percent, respectively. Two patients developed hepatitis C recurrence and were treated with interferon and ribavarin. One responded with sustained response but the other remained viraemic and died of HCC recurrence two years post-transplant. CONCLUSION: Long-term results from CHB- and CHC-related liver diseases were satisfactory and comparable to major transplant centres in the USA and Europe. Recurrence of viral hepatitis post-transplant is controllable with current antiviral therapy.

Adult↗
PubMed2004

Mitochondrial respiratory function and antioxidant capacity in normal and cirrhotic livers following partial hepatectomy.

For many liver malignancies, major hepatectomy is the usual therapy. Although a normal liver has a tremendous capacity for regeneration, liver hepatectomy in humans is usually carried out on a diseased liver and, in such cases, liver regeneration takes place in a cirrhotic remnant. Mitochondrial function in cirrhotic livers shows a variety of changes compared to control livers. This study investigated how mitochondrial respiratory function and antioxidant capacity change following partial hepatectomy of cirrhotic livers, because liver regeneration requires greater energy demands and control of oxidative stress. Cirrhosis was induced in male Wistar-Furth rats by administration of thioacetamide. NADH-cytochrome c reductase activity, mitochondrial glutathione peroxidase activity and mitochondrial GSH levels were all significantly lowered in cirrhotic livers and in the cirrhotic remnants up to 72 h after 70% hepatectomy when compared to the corresponding controls. Lower respiratory control ratios with succinate as substrate were also observed from 6 to 48 h post-hepatectomy. At 24 h post-hepatectomy, higher levels of lipid peroxidation were observed. We conclude that, compared to the controls, cirrhotic livers have diminished oxidative phosphorylation capabilities due to changes in NADH and FADH(2)-linked respiration as well as impaired antioxidant defenses following partial hepatectomy. Both of these factors, if critical, could then impede liver regeneration.

Adenosine Triphosphatases↗
PubMed2004

Adefovir dipivoxil as the rescue therapy for lamivudine-resistant hepatitis B post liver transplant.

INTRODUCTION: Complications of hepatitis B virus (HBV) infection are among the most common indications for liver transplant in many parts of Asia. However, none of the current posttransplant hepatitis B prophylaxis strategies, namely, lamivudine, hepatitis B immunoglobulin monotherapy, or combination therapy, is ideal. Our aim was to evaluate the use of adefovir dipivoxil (ADV) as a rescue therapy for posttransplant HBV patients who developed lamivudine resistance. METHODS: Twenty-two consecutive patients with HBV-related liver disease, who underwent first liver transplants from 1995 to 2002, received HBV prophylaxis with indefinite lamivudine with substitution of ADV for patients who developed drug resistance and clinical deterioration, defined as persistent elevation of transaminases or histologic deterioration. RESULTS: Sixteen patients (73%) were alive at their last follow-up and six (38%) had developed hepatitis B recurrence at a median of 46 (range 9 to 74) months posttransplant. Two with persistently normal transaminases and normal liver histology at 3 and 42 months postrecurrence have been continued on lamivudine. Four showed clinical deterioration and received ADV for a median of 24 months; all displayed normalization of transaminases and a 2 to 5 log drop in HBV DNA titers. Three had paired biopsies before and after substitution of ADV with two showing improvement and one stable appearance. The median serum creatinine value increased slightly from 126 to 138 micromol/L (P = 0.72). CONCLUSION: ADV is an effective rescue therapy for patients with lamivudine-resistant hepatitis B post-liver transplant. Further studies are needed to ascertain the optimal posttransplant hepatitis B prophylaxis.

Adenine↗
PubMed2004

Hep Par 1 expression in carcinoma of the cervix: implications for diagnosis and prognosis.

AIMS: To determine the frequency and pattern of Hep Par 1 expression in cervical carcinomas of various histological types and to correlate expression with prognostic parameters. METHODS: Twenty nine cervical carcinomas were analysed for tumour type, hepatoid and neuroendocrine differentiation, and vascular invasion. A semiquantitative analysis was performed for Hep Par 1, alpha fetoprotein, chromogranin, and synaptophysin immunoreactivity. RESULTS: Hep Par 1 expression was seen in seven of the 29 cervical carcinomas (three of seven adenocarcinomas, one of 17 squamous cell carcinomas, one of two adenocarcinomas with adenocarcinoma in situ, one of two adenocarcinomas in situ, and one of one large cell neuroendocrine carcinoma with adenocarcinoma in situ). Normal looking endocervical epithelium was also positive in one case. Cases expressing Hep Par 1, with or without neuroendocrine coexpression, were associated with a higher rate of vascular invasion and a worse prognosis. Three of the five cases expressing neuroendocrine markers also coexpressed Hep Par 1. CONCLUSIONS: Hep Par 1 expression in carcinoma of the cervix is not uncommon and is present in a variety of histological types. Expression of this marker appears to be associated with more aggressive biological behaviour and a worse prognosis. The uterine cervix is another site that may express Hep Par 1 and hence the use of this antibody in situations of diagnostic difficulty, especially involving lesions within the liver, have to be coupled with the knowledge of the range of tissues it may stain.

Adenocarcinoma↗
PubMed1999

Peptic ulcer and gastritis in uraemia, with particular reference to the effect of Helicobacter pylori infection.

AIMS: To determine: (i) the prevalence of histological gastritis and peptic ulcer; and (ii) the clinical features of peptic ulcer, in patients with end-stage renal failure. METHODS: Upper endoscopy was performed by a single observer in 268 patients with end-stage renal failure over a 6-year period. Gastric histology and Helicobacter pylori status were studied in 40 consecutive subjects in whom there were no contraindications for gastric biopsy and who had not used antibacterial drugs in the preceding 4 weeks. As there are only limited data for healthy volunteers in Singapore, 33 age-, sex- and race-matched patients with functional dyspepsia from an earlier drug trial and 18 healthy volunteers who were not age-matched were used as controls. The clinical features of 43 consecutive uraemic patients with peptic ulcer were compared with those of 118 consecutive non-uraemic peptic ulcer patients seen by the same author. RESULTS: Among uraemic patients, histological gastritis was less common, compared with healthy volunteers and functional dyspepsia patients. Helicobacter pylori infection as assessed by histology was also less common among uraemic patients compared with functional dyspepsia patients, but the difference was not statistically significant on serological assessment. Uraemic patients with ulcer had an equal sex ratio, in contrast to a male preponderance among peptic ulcer patients with normal renal function. Uraemic patients with ulcer were more likely to be pain-free, to present with haemorrhage, to have multiple ulcers and postbulbar duodenal ulcers, but were less likely to have H. pylori infection. Among uraemic subjects, the prevalence of H. pylori infection was similar whether or not peptic ulcer was present. CONCLUSIONS: The prevalence of histological gastritis was lower in uraemic patients when compared with patients with functional dyspepsia and healthy volunteers. Peptic ulcers in uraemic subjects have different clinical characteristics from peptic ulcer in non-uraemic subjects.

Adolescent↗
PubMed1999

[Carotid atherosclerosis in patients with suspected coronaropathy: the relationship to traditional risk factors in the 2 vascular areas].

UNLABELLED: In order to evaluate the prevalence of carotid atherosclerosis (CA) in patients with coronary artery disease (CAD) and to identify the differential role of traditional risk factors, we analyzed data concerning 290 patients aged 61.9 +/- 10.8 years who underwent color duplex ultrasound of extracranial arteries before coronary angiography. Significant CA (stenosis > or = 50% in at least one extracranial artery) was disclosed in 44 patients (15%); significant CAD (stenosis > or = 70% at least in a major epicardial vessel) was documented in 238 patients (82%). Age and smoking were significantly associated with both CAD (respectively, p = 0.034 and p = 0.050) and CA (respectively, p = 0.000 and p = 0.000), but a stronger correlation was documented with CA (r = 0.325 vs r = 0.125 for age; r = 0.218 vs r = 0.114 for smoking). Diabetes (p = 0.031) and male gender (p = 0.016) were significantly associated with CAD, and hypertension (p = 0.029) with CA. CONCLUSIONS: Traditional risk factors play different roles in the pathogenesis of atherosclerotic disease of carotid and coronary circulation. Color duplex evaluation of the carotid arteries can be useful in high-risk patients, particularly if candidates for coronary surgery.

Age Distribution↗
PubMed1998

Glutaraldehyde-fixed biological tissue calcification: effectiveness of mitigation by dimethylsulphoxide.

The conditions defining the extent of dimethylsulphoxide (DMSO) effectiveness in mitigating calcification of glutaraldehyde (GA)-fixed tissue have been evaluated. Exposure of GA-fixed tissue porcine aortic valve cusps to low concentrations of DMSO does not impart calcification inhibitory activity. Mitigation in calcification becomes evident only as the DMSO component nears 100% and is best when neat DMSO is used. In all instances, regardless of the DMSO concentration, exposure to DMSO resulted in an increase in the tissue shrinkage temperature, attributed to further cross-linking in the tissue. Histological examination of samples before implantation indicate some deleterious effects to the tissue, the degree dependent on concentration, time and temperature of DMSO exposure. The results of this study suggest that treatment of GA-fixed tissue with high concentrations of DMSO for a short duration at a lowered temperature could give a bioprosthesis that has good mitigating calcification properties with retention of tissue integrity.

Journal Article↗
PubMed1998

Validation of [13C]urea breath test for Helicobacter pylori using a simple gas chromatograph-mass selective detector.

OBJECTIVE: Isotope ratio mass spectrometry (IRMS) is the accepted method for accurately measuring the 13CO2:12CO2 ratio in the non-invasive and non-radioactive [13C]urea breath test (13C-UBT) for Helicobactor pylori. The IRMS instrument, an expensive and highly specialized analyser, is rarely available. The objective of this project was to modify and validate the use of a simple bench-top gas chromatograph-mass selective detector (GC-MSD) for 13C-UBT. METHODS: Breath samples from 71 patients were taken at baseline and 30 min after ingestion of 100 mg [13C]urea. The breath samples were analysed using GC-MSD in the selected ion monitoring mode. The reference 13CO2:12CO2 ratio was from NBS19 obtained from the US National Institute of Standards and Technology. 13CO2:12CO2 ratios of the breath samples were determined. Excess delta per thousand (per mil, delta/thousand) of the 30 min sample over the baseline (deltadelta/thousand) of > or = 6deltadelta/thousand was considered H. pylori positive. Results from 13C-UBT and histology determined blind to each other were compared. RESULTS: The coefficient of variation of the reference 13CO2:12CO2 ratio was 0.06%. Using histology as the 'gold standard', the sensitivity (97.9%) and specificity (95.8%) of the GC-MSD 13C-UBT were comparable to those of other methods of H. pylori diagnosis. CONCLUSION: A gas chromatograph coupled to a mass selective detector that is available in many analytical and biomedical laboratories can be used for the 13C-UBT. This method will increase the availability and reduce the cost of this non-invasive, non-radioactive diagnostic test.

Breath Tests↗
PubMed1998

Protective action of capsaicin and chilli on haemorrhagic shock-induced gastric mucosal injury in the rat.

Chilli and its pungent ingredient, capsaicin, have been shown to protect against experimental gastric mucosal injury induced by various necrotizing agents such as ethanol and aspirin and stress. We investigated the effect of capsaicin and long-term ingestion of chilli on haemorrhagic shock-induced gastric mucosal injury in the rat. Anaesthetized male Sprague-Dawley rats were subjected to haemorrhagic shock by withdrawing blood to reduce the mean arterial blood pressure to 30-40 mmHg with subsequent reinfusion of shed blood. This resulted in gastric mucosal injury with readily identifiable haemorrhagic lesions. Capsaicin (5 mg) administered prior to, but not after, haemorrhagic shock, significantly reduced the gastric mucosal injury in intact animals. Sensory ablation with capsaicin pretreatment (125 mg/kg bodyweight) abolished the gastroprotective effect afforded by capsaicin. Similarly, 4 week intake of chilli powder (360 mg daily) reduced the gastric mucosal injury in intact, but not in capsaicin-desensitized rats. Capsaicin and long-term chilli intake protected against haemorrhagic shock-induced gastric mucosal injury and the protection may be mediated by capsaicin-sensitive afferent neurons. Our studies are of potential significance in the context of stress ulcer disease in the human.

Animals↗
PubMed1998

The effect of test duration on the sensitivity and specificity of ultra-rapid urease test for the detection of Helicobacter pylori infection.

BACKGROUND: 'Home made' ultra-rapid urease tests are used extensively in the Asia Pacific region. Data on the reliability of these 'home made' tests are limited. AIMS: To evaluate the effect of test duration on the sensitivity and specificity of a self-prepared biopsy urease test for the detection of Helicobacter pylori. METHODS: Using histology as the 'gold standard', the effect of test duration on the sensitivity and specificity of a self prepared urease test for the detection of H. pylori was evaluated in 411 consecutive patients undergoing upper gastrointestinal endoscopy. RESULTS: Histology was positive for H. pylori in 217 of the 411 patients (52.8%). Within 24 hours of retrieving the specimen, 189 (87.1%) of the histology positives and 174 (89.7%) of the histology negatives were correctly identified by the urease test. Of the H. pylori positives, 72.0%, 81.0%, 89.9% and 100% were detected by the urease test within one minute, five minutes, three hours and 24 hours respectively. Thus, sensitivities of the urease test at one minute, five minutes, three hours and 24 hours were 62.7%, 70.5%, 78.3% and 87.1% respectively. Corresponding figures for the specificity were 93.8%, 93.3%, 92.3% and 89.7% respectively. Using a receiver-operating characteristic curve, an optimal combination of sensitivity and specificity was obtained when the urease test was read at 24 hours. CONCLUSIONS: While the biopsy urease test was positive in most cases within a minute, better results could be obtained if the test continued to be read over a 24 hour period.

Adolescent↗
PubMed1998

Role of capsaicin sensitive nerves in epidermal growth factor effects on gastric mucosal injury and blood flow.

BACKGROUND: Epidermal growth factor (EGF) and capsaicin protect against experimental gastric mucosal injury. Capsaicin exerts its gastroprotective effect by stimulating afferent neurones leading to release of calcitonin gene related peptide (CGRP) which causes gastric hyperaemia. EGF also causes gastric hyperaemia but whether it acts via capsaicin sensitive neurones is unknown. AIMS: To assess the influence of: (1) capsaicin desensitisation on EGF effects on gastric mucosal injury and gastric mucosal blood flow: and (2) close arterial infusion of hCGRP8-379, a CGRP antagonist, on EGF effects on gastric mucosal blood flow. METHODS: The absolute ethanol induced gastric mucosal injury model in the rat was used. Gastric mucosal damage was assessed by planimetry and light microscopy. Gastric mucosal blood flow was measured by laser Doppler flowmetry in a gastric chamber preparation. RESULTS: Capsaicin desensitisation abolished the gastroprotective and gastric hyperaemic effects of EGF. Close arterial infusion of hCGRP8-37 antagonised the hyperaemic effect of both capsaicin and EGF. CONCLUSION: Results show that EGF may exert its gastroprotective and gastric hyperaemic effects via capsaicin sensitive afferent neurones.

Animals↗
PubMed1997

Effect of cisapride on functional dyspepsia in patients with and without histological gastritis: a double-blind placebo-controlled trial.

In the present double-blind placebo-controlled study the effect of cisapride on functional dyspepsia was evaluated in patients with and without histological gastritis. Patients with functional dyspepsia and whose symptoms persisted after a 2 week run-in period with antacid treatment were randomized to receive cisapride (10 mg) or matching placebo three times daily for 4 weeks. Symptoms of epigastric pain, bloating, nausea, belching, early satiety and heartburn were graded on a four-point scale based on patients' feedback and diary card recording. A global response was also formulated by the investigators. One hundred and four patients entered the study and 76 completed the trial, comprising 36 patients with histological gastritis and 40 patients without gastritis. Symptom scores in both gastritis and non-gastritis groups were significantly improved by both cisapride and placebo; however, the improvement was not statistically different between the two treatment groups. Cisapride produced a good or better global response in 58% of subjects with histological gastritis and in 53% of subjects without gastritis compared with 47% and 52%, respectively, of patients on placebo; this difference was not statistically significant. Gastric histology did not influence the effect of cisapride on the symptoms of functional dyspepsia.

Adult↗
PubMed1997

Racial differences in Helicobacter pylori seroprevalence in Singapore: correlation with differences in peptic ulcer frequency.

The aim of this study was to determine, first, whether racial differences exist in the seroprevalence of Helicobacter pylori infection in Singapore, and second, whether these differences correlate with racial differences in peptic ulcer frequency. A commercial serological test for immunoglobulin (Ig)G antibody to H. pylori which was 90% sensitive and 83% specific in our population was used to screen 403 adult blood donors of Chinese, Malay and Indian origin, aged between 15-60 years. Serum specimens from 84 paediatric patients admitted to the Paediatrics Department, National University of Singapore, with non-gastroenterological illnesses were also tested. In all three races, seroprevalence of H. pylori increased with age. Indians have the highest prevalence of infection followed by Chinese and Malays. Peptic ulcer prevalences are known to be highest in Chinese, followed by Indians and Malays. The Malays have the lowest prevalence of H. pylori and peptic ulcer among the three races in Singapore. Indians have a higher prevalence of H. pylori antibodies but a lower frequency of peptic ulcer than the Chinese. Racial differences in peptic ulcer frequency between Chinese and Indians are not explained by the prevalence of H. pylori infection; other environmental or genetic factors may be involved.

Adolescent↗
PubMed1997

Tropical liver abscess.

Forty-one consecutive cases of liver abscesses seen at the National University Hospital, Singapore from 1988 to 1994 were reviewed. Twenty-seven cases (65%) were pyogenic, six (15%) amoebic, two (5%) tuberculous and six (15%) indeterminate. The predominance of pyogenic abscesses is in marked contrast to previous studies from the region a decade ago in which amoebic abscesses were the commonest type. The commonest pathogen causing pyogenic abscess was Klebsiella pneumoniae. Two cases were due to Mycobacterium tuberculosis, and this organism needs to be actively looked for in smears and cultures of aspirated material. As the majority of organisms isolated were resistant to ampicillin, empirical antibiotic treatment for suspected pyogenic abscess should include gentamicin or a cephalosporin. Percutaneous needle aspiration of the abscess was performed for 85% of pyogenic abscesses and surgery was necessary in only two cases because of complications. We found that percutaneous aspiration of liver abscess is helpful to confirm the diagnosis, provides a better bacteriological culture yield, gives a good outcome, and may uncover clinically unsuspected conditions like malignancy and tuberculoma which may mimic the presentation of liver abscesses. We recommend routine cytological examination of aspirated abscess material as well as stains and cultures for acid-fast bacilli.

Adult↗