PubMed Health⌕ Search

Biomedical subjects

E H Sng

Publications and source records attributed to E H Sng.

At least 19 recordsLinked to original sources
PubMed1992

Anti-toxoplasma serotitres in uveitis and ocular toxoplasmosis.

This study was based on anti-toxoplasma serotitres obtained from 80 normal healthy adults and 103 consecutive patients with anterior, posterior and panuveitis over a 42 month period. Twelve out of 80 (15%) normal healthy sera were found to have low titres (1:64 to 1:256), while 3 (3.8%) had high titres (1:1024 or higher). The distribution of serotitres in patients with clinical toxoplasmosis was significantly different from the population sample (p less than 0.001, chi-squared test). Similarly, the distribution of serotitres in patients with posterior uveitis (of which 28 out of 54 were clinically ocular toxoplasmosis) having serotitres of 1:1024 or greater, was found to be significantly different from the normal population (p less than 0.001, Chi-squared test), but not statistically different from those with clinical ocular toxoplasmosis. Hence, anti-toxoplasma serotitre is useful as a diagnostic screening tool only in patients with posterior uveitis. It is also useful in confirming cases of suspected clinically positive ocular toxoplasmosis in our local population.

Adolescent↗
PubMed1991

Characterisation of PPNG and non-PPNG Neisseria gonorrhoeae isolates from Singapore.

OBJECTIVE: To characterise Neisseria gonorrhoeae isolates from Singapore. DESIGN: Characterisation of Neisseria gonorrhoeae isolates by auxotyping, serological analysis and plasmid profile analysis. SPECIMENS: Sixty randomly collected isolates from 41 symptomatic, untreated males and 19 female prostitutes were studied. RESULTS: Auxotyping of 25 PPNG and 35 non-PPNG strains showed that the Pro-auxotype was prevalent among both PPNG (56%) and non-PPNG (42.5%) strains. Prototrophic strains comprised 28% of PPNG and 32.5% of non-PPNG strains respectively. Serovar analysis showed that with the exception of seven serogroup WI strains, the majority belonged to serogroup WII/III. Serovar Aedih was predominant among both serogroup WI PPNG (80%) and non-PPNG (100%) strains. Serogroup WII/III PPNG strains were represented by nine serovars with the predominant serovars being Bacjk (28%) and Bcgjk (16%). Eleven serovars were identified in the WII/III non-PPNG strains and the major serovars were Bajk (20%), Bacjk (17%), Back (11.4%) and Beghjk (11.4%). Analysis of the 25 PPNG strains showed that 16 of them carried the 4.4 MDa (Asian type) resistance plasmid and nine strains harboured the 4.4 MDa plasmid in conjunction with the 24.5 MDa transfer plasmid. The cryptic plasmid of 2.6 MDa was present in 27 of the 35 non-PPNG strains. Five of the non-PPNG strains harbouring the cryptic plasmid also contained the 24.5 MDa transfer plasmid. The plasmid combination of 2.6 + 7.8 + 24.5 MDa was detected in three non-PPNG strains. CONCLUSION: The combination of epidemiological methods used in this study indicated the heterogeneity of N gonorrhoeae strains in Singapore. A total of 16 different combinations of auxotype, plasmid profile and serovar were seen in the 25 PPNG strains compared with 24 such combinations in the 35 non-PPNG strains. Such sensitive differentiation would otherwise not be possible using either auxotype-serovar (A/S) or auxotype-plasmid analysis.

Female↗
PubMed1991

Four patients in Singapore with anti-Golgi antibodies.

Serum specimens for anti-nuclear fluorescence tests are routinely received in our laboratory. Four specimens were spotted to be negative for anti-nuclear fluorescence but positive for fluorescence characteristic of that caused by anti-golgi antibodies. (a) Patient A had acute glomerulonephritis; (b) Patient B had acute viral hepatitis; (c) Patient C had deep vein thrombosis; and (d) Patient D had non-Hodgkin's lymphoma. The relevance and possible aetiology of anti-golgi antibodies are also discussed.

Acute Disease↗
PubMed1991

Anti-toxoplasma antibodies in healthy adults and in different patient categories.

This study analyzes the anti-toxoplasma sero-titres and prevalence rates in normal healthy adults and in patients presenting with different symptom-complexes. The study was based on sera from 80 normal healthy adults and 2,185 patient sera samples from 2,032 patients (from various clinics and hospitals in Singapore) being investigated for the diagnosis or exclusion of toxoplasmosis, over a 42-month study period. About 15% of the healthy adults were found to have low IgG antibody titres (1:64 to 1:256), while 3.8% had high IgG titres (1:1024 or higher). Interestingly, among the patients investigated for toxoplasmosis: i) more than 20% of those presenting with lymphadenopathy (usually cervical) had antibody titres more than or equal to 1:1024; ii) more than half of all patients with an antibody titre of 1:4096, and more than three-quarters of all patients with a titre exceeding 1:4096 had presented with lymphadenopathy; iii) about 20% of those presenting with ocular symptoms had low antibody titres of 1:64 or 1:256, whereas 7% had higher titres. Malay (p less than 0.01) and Indian (p less than 0.05) patients had significantly higher seropositive rates than the Chinese. In particular, the Malays (p less than 0.00001) and Indians (p less than 0.01) had significantly higher incidence of low-positive titres (1:64, 1:256); conversely the Chinese patients had a significantly higher (p less than 0.01) incidence of high-positive titres (1:4096 or higher). Finally, the epidemiology and clinical profiles of patients presenting with acute toxoplasmic lymphadenitis are contrasted with that of patients presenting with ocular manifestations of congenital toxoplasmosis.

Adult↗
PubMed1991

Human immunodeficiency virus infection in Singapore--containment strategies.

The worldwide occurrence of the Acquired Immunodeficiency Syndrome (AIDS) since its advent in the United States in 1981 has resulted in a global dilemma on how best to reduce transmission of the Human Immunodeficiency Virus (HIV). In Singapore, a national AIDS programme was established in 1985 to control the spread of the disease in the country. The programme included health care delivery, education of health care workers and the community, surveillance and counselling of individuals with high risk behaviours, as well as protection of the nation's blood supply. This paper examines the global response to the HIV pandemic and containment strategies appropriate to Singapore based on established epidemiological data.

AIDS Serodiagnosis↗
PubMed1991

A review of 58 patients in Singapore with significantly high anti-Toxoplasma serotitres.

Over a 42-month period, 58 patients presenting at the Singapore General Hospital were identified to have IgG anti-Toxoplasma serotitres of 1:1024 or higher by the indirect immunofluorescence test. This retrospective study examines the clinical presentation and management of these 58 patients. About 60% of these 58 patients had presented with lymphadenopathy, 20% with ocular symptoms and 14% with bad obstetric history. Almost all patients with IgG anti-Toxoplasma serotitres exceeding 1:1024 had presented with lymphadenopathy (with a modal titre of 1:4096). In contrast, most of the patients who presented with ocular symptoms or bad obstetric history had lower modal titres. The majority of patients who had presented with lymphadenopathy were Chinese, aged 21 to 35. Typically, they presented with a painless, mobile, solitary cervical node of three to four weeks duration as the only symptom, had biopsies where the histopathology was suggestive of toxoplasmosis, received no treatment and experienced no sequelae. The study concludes that: acute toxoplasmosis is common in Singapore and presents typically as asymptomatic cervical lymphadenopathy in a young Chinese; the incidence of congenital infection is also believed to be high, based on the number of cases presenting with fetal wastage and the prevalence of ocular toxoplasmosis; pigs in Singapore may constitute an important reservoir for the transmission of this disease to man.

Adult↗
PubMed1990

Human immunodeficiency virus infection in Singapore--the first 50 cases.

As at 31 May 1990, fifty Singaporeans with the Human Immunodeficiency Virus (HIV) infection had been detected. Of these, nineteen had the Acquired Immunodeficiency Syndrome (AIDS). The majority of infected persons had been infected through sexual contact (homosexual 52%; bisexual 24%; heterosexual 20%) with men and women from countries where HIV infection was prevalent. The majority of infected patients (88%) were in the age range 20-39 years. There was one case of blood transfusion-associated AIDS. There were no infected paediatric or haemophiliac cases or intravenous drug use in any of the patients. A spectrum of AIDS-related opportunistic infections and cancers was observed, and Pneumocystis carinii pneumonia was the most frequent presentation. Thirteen patients with AIDS had died and the median survival time was about seven months.

Acquired Immunodeficiency Syndrome↗
PubMed1989

Rapid in situ generation of DNA restriction endonuclease patterns for Neisseria gonorrhoeae.

Restriction endonuclease (RE) digestion patterns of 26 isolates of Neisseria gonorrhoeae representing different serovars of serogroups WI, WII, and WIII were generated by agarose pellet entrapment and in situ digestion with HinfI and BglII. The method was fast, simple, and reproducible, and stable RE patterns were produced from subsequent in vitro passages. The cost of culture materials was reduced considerably, and no toxic or flammable solvents needed to be used. Excellent resolution of DNA fragments of higher molecular weights was obtained as a result of minimal mechanical shearing of the DNA. The REs HinfI and BglII were discriminative in the fragment length ranges of 2 to 6.5 and 2.5 to 21.5 kilobases, respectively. On the basis of densitometric scanning of electrophoretograms generated by HinfI digestion, the 26 isolates representing 12 serovars were divided into seven groups. BglII was found to be more discriminative; 15 RE patterns were established among the 26 isolates. Patterns generated by both REs showed that there was no correlation between a particular RE pattern and a serovar, since strains with identical RE patterns were from different serovars. With the exception of two strains (D3 and D14), which demonstrated positive correlation when both enzymes were used, all strains with identical serovar patterns had different RE patterns.

DNA, Bacterial↗
PubMed1989

Epidemiology of acute epididymo-orchitis in Singapore.

A prospective study on 55 patients with acute epididymo-orchitis was studied. Their ages ranged from 15 to 65 years. Thirty-three (60%) were within the 20-29 year age group and 9 were above 35 years of age. 69% cited prostitutes as the source of sexual contact. Twenty-six patients did not receive and 29 patients received antibiotic therapy before recruitment. In the former untreated group, 6 patients (23%) had gonococcal urethritis, 3 patients (11%) had chlamydial urethritis and 2 patients (8%) had combined gonococcal and chlamydial urethritis. No pathogens were isolated from the urethra from the remaining 15 (58%) patients, 8 of whom had nonspecific urethritis. In the latter treated group, 4 patients (14%) had gonococcal urethritis and no organisms were isolated from the remaining 25 (86%) of whom 6 had non-specific urethritis. None of the 55 patients had urinary tract infections. Forty-three patients (78%) had unilateral involvement of both the testis and epididymis, and 4 patients (7%) had bilateral epididymo-orchitis. Semen analysis was performed on 13 patients of whom 8 showed pyospermia.

Acute Disease↗
PubMed1989

The role of counterimmunoelectrophoresis in the identification of antibodies to extractable nuclear antigens.

Antibodies to saline-extractable nuclear antigens are hallmarks of autoimmune diseases including systemic lupus erythematosus (SLE), mixed connective tissue disease, progressive systemic sclerosis and Sjogren's syndrome. In our laboratory, we use counterimmunoelectrophoresis as a screening test and immunodiffusion as a confirmatory test to identify these autoantibodies. This study examines the drawbacks of such an approach. Though 17 out of 19 sera that formed ribonuclease sensitive lines with rabbit thymus extract on counterimmunoelectrophoresis were confirmed to have anti-RNP by immunodiffusion, sera of several different autoantibody specificities were seen to form ribonuclease resistant precipitin lines with the thymus extract on counterimmunoelectrophoresis. Having screened sera to have autoantibodies by counterimmunoelectrophoresis, the identity of some of these autoantibodies were not confirmed because of the poor sensitivity of immunodiffusion or because inappropriate controls had been used for the confirmatory immunodiffusion test. To check these drawbacks and to obviate the need for a confirmatory test, a modification of the current approach is suggested.

Animals↗
PubMed1989

Chlamydial infection in female prostitutes in Singapore.

Three studies conducted in 1982, 1985 and 1988 investigated chlamydial infections in female prostitutes. In 1982, 115 prostitutes with culture-positive gonorrhoea were studied; 8% were coinfected with Chlamydia trachomatis. In 1985, 86 female prostitutes and in 1988, 100 female prostitutes attending for routine tests were examined. Chlamydia trachomatis was isolated in 12% and 9% of the cases, respectively. Gonorrhoea was detected in 10% and 11% of the cases. In the 1988 study, one (9%) of the 11 women with gonorrhoea had concomitant chlamydial infection. Syphilis was diagnosed in 3% of the female prostitutes investigated in 1988. Our findings indicate that concomitant chlamydial infection occurs in about 8-9% of female prostitutes with gonorrhoea and that 9-12% of the female prostitutes screened harboured Chlamydia trachomatis in their endocervices. A chlamydial control programme in prostitutes is desirable.

Chlamydia Infections↗
PubMed1989

Endocervical chlamydial infection in female contacts of patients with nongonococcal urethritis.

Eighty-five female contacts of patients with nongonococcal urethritis attending Middle Road Hospital were examined. Chlamydia trachomatis was isolated from the cervix in 39% of them. Forty-five per cent of the chlamydia-positive patients were asymptomatic and 79% of them showed signs of a cervicitis. None of the patients developed complications. Neisseria gonorrhoeae was not isolated from any of the patients. Clinical markers other than cervicitis are not useful for detecting chlamydial infections in female contacts of NGU. Until such time when cheaper, more convenient and accurate methods of laboratory diagnosis of C. trachomatis are put to routine use, it would seem prudent to treat all female contacts of NGU patients after exclusion of other sexually transmitted diseases.

Adolescent↗
PubMed1989

Endocervical chlamydial infection in women attending a sexually transmitted disease clinic in Singapore.

Two hundred women attending the sexually transmitted disease (STD) clinic at Middle Road Hospital were investigated. Chlamydia trachomatis was isolated from 32% of women who were contacts of men with nongonococcal urethritis, 15% of contacts of gonococcal urethritis, 27% of contacts of unspecified STD, and 13% of women without any history of STD in their sex partners. Overall, Chlamydia trachomatis was isolated from 17% of 200 women, Neisseria gonorrhoeae from 13% of 199 women, Candida albicans from 34% and Trichomonas vaginalis from 6% of 197 women. Three per cent of the patients had positive VDRL results. A history of bilateral lower abdominal pain and the presence of cervicitis were significantly associated with chlamydial infection. Forty one per cent of the 34 chlamydia-positive women were asymptomatic. The results of this study show that C. trachomatis infection is more common than infection with N. gonorrhoeae in women who attend STD clinics. The need for routine screening and treatment on the basis of epidemiological and clinical markers of infection has to be carefully examined.

Adolescent↗
PubMed1989

Endocervical chlamydial infection in women with gonorrhoea.

Eighty six women attending Middle Road Hospital with endocervical gonococcal infection were evaluated. Chlamydia trachomatis was isolated in 27% of them. Women co-infected with C. trachomatis were similar to those with gonococcal infection alone in terms of demography, type of sexual contact, previous sexually transmitted disease, genitourinary symptoms, and clinical signs.

Chlamydia Infections↗
PubMed1989

Evaluation of cerebrospinal fluid in asymptomatic late syphilis.

A prospective study of the cerebrospinal fluid (CSF) of 49 previously untreated patients with asymptomatic late syphilis of more than two year's duration was conducted. The sera of all patients had reactive fluorescent treponemal antibody absorption (FTA-Abs) tests or Treponema pallidum haemagglutination tests (TPHA), and reactive or non-reactive Venereal Disease Research Laboratory (VDRL) tests. Five (10%) patients had abnormal CSF findings; these included elevated protein in four of 49 and pleocytosis in three of 49. Asymptomatic neurosyphilis, diagnosed on the basis of a reactive VDRL test of the CSF, was present in one (2%) of 49 patients.

Adult↗
PubMed1989

Relation of antinuclear fluorescence patterns and titres to autoantibody prevalence.

Different profiles of antinuclear antibodies (ANAs) have been found to be associated with different connective tissue diseases. Though several techniques have been developed to detect ANA, indirect antinuclear immunofluorescence (ANF) continues to be the most widely used and accepted. This study assesses the role of ANF as a screening test. The ANF patterns of 428 patients were studied. About 23% of patients with homogenous ANF patterns and 13% with speckled patterns were eventually shown to have raised anti-dsDNA titres. The percentage of patients harbouring raised titres of anti-dsDNA and the absolute titres were both seen to rise with the ANF titres. None of the patients with low ANF titres (1:40) harboured antibodies to extractable nuclea antigens (ENAs) whereas with increasing ANF titres the incidence of these autoantibodies was also seen to rise. Finally, it was noted that more than 80% of patients with high ANF titres demonstrated autoantibodies to ENA and/or dsDNA.

Antibodies, Antinuclear↗
PubMed1989

Evaluation of an ELISA method for the measurement of antibodies to dsDNA.

Anti-dsDNA is found in 60-70% of patients with active, untreated systemic lupus erythematosus (SLE) and its detection serves as an important tool in the diagnosis and monitoring of these patients. This study evaluates the use of an Enzyme Linked Immunosorbent Assay (Elisa) to detect these antibodies. Its performance is also compared to the older, but established, method of detecting anti-dsDNA using Crithidia luciliae. The sera of the 56 normal healthy blood donors revealed a mean anti-dsDNA titre of 0.93mg% with a standard deviation of 0.23mg%. All 14 patients found to be negative by the Elisa method and 10 of the 11 patients found to have borderline anti-dsDNA Elisa titres were negative by immunofluorescence. 35 patients were found to harbour raised titres of anti-dsDNA by the Elisa method. All patients found to have anti-dsDNA titres exceeding 2mg% by the Elisa test were also positive by immunofluorescence. In fact, those with very high titres by the Elisa test were also strongly (titre greater than 1:100) positive by immunofluorescence. As a measurement of the kit's accuracy, the percentage of recovery of the activity of known amounts of antibody in a specimen fell within the range of about 89-104%. As a measurement of the kit's reproducibility, the coefficient of variation in the assayed titres of sample replicates was found to be 7.5% for within-batch assays and 9.7% for between-batch assays. The Elisa assay compared favourably to the immunofluorescence test in terms of enhanced sensitivity, quantitative approach with an objective end-point and the large number of samples that may be assayed simultaneously.

Antibodies, Antinuclear↗