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Biomedical subjects

S Y Tan

Publications and source records attributed to S Y Tan.

At least 73 records · Page 4Linked to original sources
PubMed2000

FcgammaRIIa polymorphism in systemic lupus erythematosus.

FcgammaRIIs are the most widely distributed of the Fcgamma receptor family and play an important role in the clearance of immune complexes. Evidence that the FcgammaRIIa-R131 allotype is less able to process and clear immune complexes effectively suggests that this may be a disease susceptibility factor for systemic lupus erythematosus (SLE). Data from studies published thus far do not agree on the potential role of FcgammaRIIa polymorphism in the genetics of SLE. Most studies in fact show no evidence for any correlation between polymorphism of FcgammaRIIa and risk for SLE. However, it remains to be determined whether FcgammaRIIa polymorphism may play a critical role in certain groups of patients, especially in those of differing ethnic background. Polymorphism of FcgammaRIIa may also be important in determining disease phenotype, and identification of this influence may have important implications in patient care and in identifying patients for more aggressive therapy.

Antigens, CD↗
PubMed2000

Identification of multiple genital HPV types and sequence variants by consensus and nested type-specific PCR coupled with cycle sequencing.

Consensus and type-specific HPV primers were employed for PCR and cycle sequencing of genital HPVs in scrapings and colposcopically directed biopsies of the cervix from a cohort of 188 female sex workers. A total of 27 individuals tested positive for a broad spectrum of HPV types, including HPVs 6b, 16, 18, 31, 33, 34, 35, 45, 56 and 58, as well as a new HPV type, with seven individuals displaying dual infections. Good correlation between the results of individually paired samples was observed. A HPV 16 primer biotinylated at the 5' end was also used as a probe, which could successfully detect amplified products of HPV 16 but not other HPV types tested by an automated ELISA detection system. DNA sequence analysis revealed several HPV sequence variants that harbored mutations, especially in the E6 gene, many of which culminated in non-conservative amino acid substitutions in the transforming E6 oncoprotein. Such an approach of coupling PCR with cycle sequencing permits the determination of many known and even novel HPV types associated with varying degrees of risk to cervical carcinogenesis, and enables the identification of HPV sequence variants of putative biological and clinical significance, thus justifying its utility as an adjunct tool to complement cervical cytology and colposcopy. This study also emphasises the need for educational, interventional and behavioral modification to minimise HPV transmission, such as through consistent condom usage among sex workers.

Cervix Uteri↗
PubMed2000

Rapid prenatal diagnosis of chromosome abnormalities.

The aim of the present work was to examine the efficacy of using FISH for the rapid prenatal diagnosis of common chromosome aneuploidies. A total of 100 analyses over a six month period were included in the study. Diagnosis was possible in all cases. A mosaic for trisomy 21 proved, by comparison with an extensive analysis of long term cultures, to be an apparent false positive. Otherwise the technique was reliable, accurate and relatively straightforward to perform. Results could be available within 24 hrs. In most cases an additional long term full analysis was also done, so as to exclude rarer aneuploidies and structural rearrangements. This methodology is seen as a useful addition to the prenatal diagnostic repertoire.

Chromosome Aberrations↗
PubMed1999

Interstitial deletion of chromosome 5 in a neonate due to maternal insertion, ins(8;5)(p23;q33q35).

We describe an infant girl with an interstitial deletion of chromosome bands 5q33 to 5q35 inherited from a maternal interchromosomal insertion ins(8;5)(p23;q33q35) which was demonstrated by fluorescent in situ hybridization with whole chromosome paints. Physical anomalies included hypertonicity, microcephaly, short neck, apparently low-set ears, micrognathia, camptodactyly, mild rocker bottom feet, and hammer toe. Cardiac anomalies included a large ventricular septal defect, patent ductus arteriosus, pulmonary hypertension and hypoplastic right ventricle. She died at age 3 months.

Abnormalities, Multiple↗
PubMed1999

An improved model of galactosamine-induced fulminant hepatic failure in the pig.

Fulminant hepatic failure is a serious condition with very high mortality. Development of new therapies designed to bridge the patient through the acute period of their disease has been hampered by the lack of a large animal model that closely reproduces the changes in humans. We have established an improved model of fulminant hepatic failure in the pig by administration of an aminosugar d-galactosamine hydrochloride. Galactosamine in a dose of 1.0 g/kg was dissolved in 5% dextrose in water (D5W) and given intravenously to seven young pigs weighing 8 to 15 kg. Seven control pigs received an equal volume of D5W alone. Two days prior to injection, a baseline ultrasound-guided liver biopsy was done in each pig under general anesthesia using isofluorane. Clinical data were recorded and blood for laboratory determinations was drawn at 0 h (baseline), 24 h, 48 h, and 72 h after infusion of galactosamine or D5W alone, under general anesthesia. Neurological data were recorded at the same intervals before inducing anesthesia. Galactosamine-treated animals showed 100% mortality. All of them died by 86 h after injection of galactosamine, with death resulting from fulminant hepatic failure characterized by marked increases in total bilirubin, liver enzymes, ammonia, and lactate; associated coagulopathy; hypoglycemia; and coma. Liver histology showed massive hepatocellular necrosis in all seven galactosamine-treated animals. This large and highly reproducible animal model appears promising for future evaluation of bioartificial liver support systems designed to treat fulminant hepatic failure in humans.

Animals↗
PubMed1999

Five micro-curie urea breath test for the diagnosis of Helicobacter pylori infection: evaluation in a South-East Asian population.

BACKGROUND: Helicobacter pylori is an important pathogen responsible for significant morbidity and mortality. Its prevalence varies widely in different geographical locations and is especially high in parts of Asia. METHODS: A double-blind study was carried out to evaluate the use of the 5 microCi (185 KBq) [14C]-urea breath test ([14C]-UBT) in a South-East Asian population by validating its diagnostic accuracy against histology and the CLO test. RESULTS: The sensitivity and specificity of the [14C]-UBT was 100% when compared against the CLO test. When histology was used as the 'gold standard', the sensitivity and specificity were 100% and 97.2%, respectively. There was no overlap or indeterminate values between positive and negative results on the [14C]-UBT. CONCLUSIONS: Among South-East Asian populations where the prevalence of H. pylori infection is high, the high sensitivity of the 5 microCi [14C]-UBT makes it a very important test in the detection of H. pylori.

Adult↗
PubMed1999

Risk of gonadoblastoma in female patients with Y chromosome abnormalities and dysgenetic gonads.

We report two female patients with gonadal dysgenesis and sex chromosome mosaicism involving the Y chromosome. Conventional karyotyping was supplemented with fluorescent in situ hybridisation techniques in order to confirm the presence of Y chromosomes. One patient is a phenotypic female with karyotype 45,X/46,X,idic(Y)(q11.2). She underwent a laparoscopic gonadectomy at which streak ovaries without evidence of gonadoblastoma were removed. The second patient presented as a virilised female with karyotype 45,X/47,XYY. At laparoscopy, she was found to have mixed gonadal dysgenesis with a gonadoblastoma in situ. We recommend early gonadectomy in female children presenting with gonadal dysgenesis and the presence of a Y chromosome although once the gonadoblastoma locus on Y chromosome gene has been cloned it may be possible to identify those patients who have a low risk of developing gonadoblastoma.

Child, Preschool↗
PubMed1999

Clinical, radiological and serum amyloid P component scintigraphic features of beta2-microglobulin amyloidosis associated with continuous ambulatory peritoneal dialysis.

BACKGROUND: Beta2-Microglobulin (beta2M) amyloidosis occurs in patients with end-stage renal failure (ESRF) who undergo long-term continuous ambulatory peritoneal dialysis (CAPD), but its prevalence in patients treated exclusively by CAPD is unknown. In addition, its features may differ from those of haemodialysis-associated beta2M amyloidosis because CAPD is more biocompatible. METHODS: We performed serum amyloid P component (SAP) scintigraphy, a specific technique for imaging amyloid deposits, in 13 consecutive patients with ESRF who had been dialysed for >5 years, at least 80% of the time by CAPD. Clinical and radiological features of beta2M amyloidosis were sought and compared with the results of SAP scintigraphy. RESULTS: SAP scans showed articular amyloid deposits in seven patients, all of whom had evidence of carpal tunnel syndrome and four of whom had arthralgia characteristic of dialysis amyloidosis. Typical radiographic bone cysts were present in only one case who had been dialysed for >17 years. The remaining six patients had no clinical, radiological or scintigraphic evidence of beta2M amyloidosis. CONCLUSIONS: The prevalence of beta2M amyloidosis in this study was comparable with that in reported haemodialysis populations. Many of the amyloid deposits demonstrated by SAP scintigraphy were not associated with symptoms, but larger and longer term studies are required to determine whether CAPD favourably influences their clinical expression.

Adult↗
PubMed1999

Human Fc gamma receptor IIA (FcgammaRIIA) genotyping and association with systemic lupus erythematosus (SLE) in Chinese and Malays in Malaysia.

SLE is an autoimmune and polygenic disorder characterized by an accumulation and deposition of immune complexes. Several studies have indicated differential impact of FcgammaR polymorphism genotypes in different ethnic groups studied. The Fc receptor for IgG class IIA gene (FcgammaRIIA) occurs in two allelic forms. The allele FcgammaRIIA-H131 encodes a receptor with a histidine at the 131 amino acid position; the other allele FcgammaRIIA-R131 encodes an arginine. This polymorphism is believed to determine the affinity of the receptor for hIgG2 in immune complexes. FcgammaRIIA-H131 has a higher capacity for hIgG2 compared to FcgammaRIIA-R131 as measured by in vitro studies of insoluble immune complex clearance. We have investigated the polymorphism for FcgammaRIIA using a novel polymerase chain reaction-allele specific primer (PCR-ASP) method designed specifically to distinguish the two allelic forms. Our studies were based on 175 Chinese and 50 Malays SLE patients as well as 108 and 50 ethnically matched healthy controls for the respective groups. Analysis of the data (chi2 test with Yates correction factors and odds ratios) revealed that there were no significant differences between SLE patients and controls. We have not found evidence of a protective effect conferred by FcgammaRIIA-H131 in the ethnic groups studied.

Alleles↗
PubMed1999

The viability of liver graft for transplantation after prolonged warm ischaemia.

Maximum duration of warm ischaemia within which the liver graft is viable for transplantation remains undefined. Published data on porcine allogeneic liver transplantation (LTx) using non heart beating donors (NHBDs) are conflicting because technical details like the hepatic artery status, systemic heparinisation of donor animals and duration of rewarming were not addressed. We described a novel porcine model which simulate conditions of transplantation from NHBDs. The pigs were divided into three groups of 6 each. Groups I, II and III were subjected to 60, 90 and 120 minutes of warm ischaemia, respectively. Liver viability was assessed using four parameters: serum liver function tests (serum bilirubin and transaminase), dynamic liver function test i.e. the monoethylglycinexylidide (MEGX) formation test, morphological assessment and animal survival. All animals in groups I and II (90 minutes of warm ischaemia or less) survived but 50% of animals in group III died of massive liver failure. Given that rewarming period required in actual allogeneic LTx is about 60 minutes, the safe period for intervention in NHBDs is determined to be about 30 minutes. Allogeneic porcine LTx using NHBDs with 30 minutes of cardiac arrest were performed in 5 animals. All of them survived.

Alanine Transaminase↗
PubMed1999

Ring chromosome 22 resulting in partial monosomy in a mentally retarded boy.

We describe a 7-year-old boy presenting with mental retardation and hyperactivity. Clinical features include microcephaly, hypertelorism, epicanthic eye folds and antimongoloid slant. He also has large ears, large hands and feet, and torticollis. The karyotype was 46, XY, r (22) (p13q13). In situ hybridisation studies with a subtelomeric probe for distal 22q confirmed that the ring was deleted causing partial monosomy of 22q.

Abnormalities, Multiple↗
PubMed1998

Comparison of the Brief Psychiatric Rating Scale and the Brief Symptom Inventory.

General psychopathology rating scales have multiple uses and have been used extensively. These rating scales may be found in several forms including an interview procedure and self-report. The advantages of self-report measures, as well as their possible deficits, were discussed. Because there are so many varying kinds of rating scales, criteria were set forth as to how to evaluate scales. An interview with a rating scale, the Brief Psychiatric Rating Scale (BPRS), and a self-report measure, the Brief Symptom Inventory (BSI), were compared in this study. The BPRS has been widely used and has been evaluated as one of the very best rating scales. However, experienced raters and more time are needed to administer the BPRS. The BSI is highly evaluated as one of the best brief self-report measures and requires much less professional time. Both instruments have high reliability and validity. Correlations of the BPRS total score with the total scores on the BSI were significant, as were correlations of the depression, anxiety, and hostility subscales on each instrument. Therefore, either scale could be used for a brief assessment of overall symptomatology, depression, anxiety, and hostility. However, it is suggested that the subscales should be compared to other criteria to measure their convergent validity.

Adult↗