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H H Tan

Publications and source records attributed to H H Tan.

At least 37 records · Page 2Linked to original sources
PubMed2002

A review of cutaneous granulomas and lupus vulgaris following BCG vaccination in a skin hospital in Singapore.

INTRODUCTION: Since the introduction of BCG vaccination in 1921, there have been numerous reports of cutaneous complications. Although common local effects such as erythema, soreness and local abscesses are well known, the incidence of cutaneous granulomas and BCG-induced lupus vulgaris is rare. PATIENTS AND METHODS: This is a retrospective analysis of our local experience in dealing with cases of cutaneous granulomas following BCG vaccination. Cases were seen at a local tertiary level dermatological referral centre. RESULTS: There were 14 cases seen over an 8-year period. Of these cases, 4 were clinically suggestive of BCG-induced lupus vulgaris, but only 1 of these cases was confirmed by culture. All but one of these cases had developed these complications after multiple BCG vaccinations. The 3 suspected but unconfirmed cases were treated with isoniazid. The 1 case of confirmed BCG-induced lupus vulgaris was treated with rifampicin and ethambutol, as sensitivity testing revealed resistance to isoniazid. All 4 cases responded well to treatment. The other 10 cases of vaccine-induced cutaneous granulomas responded to local symptomatic treatment. CONCLUSIONS: Although local effects such as induration and pustule formation at the injection site are not rare, the development of cutaneous granulomas is uncommon. Incidence of complications increases with multiple vaccinations. Cases usually respond to local symptomatic therapy, while more aggressive lesions responded to the use of oral isoniazid. Confirmed cases of BCG-induced lupus vulgaris should be treated based on antibiotic sensitivity profile.

Adolescent↗
PubMed2001

An exploratory study on the career anchors of educators in Singapore.

In this exploratory study, the authors adopted an empirical approach to determine the various primary career anchors possessed by Singapore educators, the impact of the degree of congruency between teaching and the career anchors on intrinsic and extrinsic satisfaction, and turnover intentions. A number of hypotheses were supported and provided the 1st step in understanding this group of important individuals who nuture the future generation of human capital for the workplace.

Adult↗
PubMed2001

Application of selective implantation in Al0.5Ga0.5As/In0.25Ga0.75As/GaAs pseudomorphic single quantum wire structures.

A pseudomorphic Al0.5Ga0.5As/In0.25Ga0.75As/GaAs asymmetric quantum wire (QWR) structure was grown on GaAs V-grooved substrate by low pressure metal organic vapor phase epitaxy. The formation of crescent shaped QWRs at the bottom of the V-grooves was confirmed by both transmission electron microscopy and photoluminescence (PL) spectra. The temperature dependence of PL spectra demonstrated a fast decrease of the sidewall quantum well PL intensity with increasing temperature, which originates from relaxation of carriers from well to wire region. The self-aligned dual implantation technique was successfully used to selectively disable the adjacent quantum structures. Decrease of the PL intensity of QWR at 8 K was observed after selective implantation, which resulted from a decreased number of carriers relaxed from adjacent quantum structures.

Aluminum↗
PubMed2001

Parasitic skin infections in the elderly: recognition and drug treatment.

There are many parasitic infections of medical importance, which can produce both systemic disease as well as skin lesions. For the most part, treatment of these infections in the elderly does not differ very much from that of younger patients. However, one must be aware that the geriatric population can present with certain challenges with regard to diagnosis of these diseases because history taking may be more difficult and patients often already have a set of other medical problems, which may overshadow the skin lesions. In addition, the clinical manifestations of these infections may not appear classical and may be altered. Dosages of drugs used to treat these infections, even topical agents, may require adjustments in this population. The recognition of scabies in elderly people living together is important and early treatment with topical scabiecides, including oral ivermectin, will help to control the spread of the infestation. Pediculosis may be a cause of pruritus in the elderly and can be treated with malathione, lindane or permethrin. Less common parasitic infections in the elderly, including cutaneous larva migrans and cutaneous leishmaniasis, present with a characteristic clinical picture and can be effectively treated with oral thiabendazole and intravenous antimonials.

Aged↗
PubMed2001

Antibiotic sensitivity of Propionibacterium acnes isolates from patients with acne vulgaris in a tertiary dermatological referral centre in Singapore.

OBJECTIVES: To study the minimum inhibitory concentrations (MICs) of Propionibacterium acnes (P. acnes) isolates to selected antibiotics from patients with acne vulgaris in Singapore and determine if resistance increases with prolonged use of antibiotics. DESIGN: A single-centre prospective study. SETTING: Tertiary dermatological referral centre in Singapore. PATIENTS: One hundred and fifty patients with acne vulgaris seen at the National Skin Centre. RESULTS: In patients who had never been on antibiotics, there were no resistant isolates of P. acnes. In patients who had been on short-term antibiotics (between 6 to 18 weeks), there were 2 resistant strains among the 34 isolates (6.25%); in patients who had been on antibiotics for longer periods, there were 11 resistant strains among the 51 isolates (21.6%). The differences in the rates of isolation of resistant strains between patients who had not been on antibiotics to those that had been on long-term antibiotics were statistically significant (P = 0.015). There was also a significant difference in isolation of resistant strains from those on short-term antibiotics compared to those who had been on long-term antibiotics (P = 0.036). Resistance to erythromycin was most commonly encountered. Most of the erythromycin-resistant strains also showed cross-resistance to clindamycin. The average MICs to antibiotics such as minocycline, erythromycin and clindamycin in those on long-term antibiotics were significantly higher when compared to patients who had not been on antibiotics. CONCLUSIONS: Antibiotic resistance in P. acnes isolates in Singapore follows similar patterns to studies conducted in Europe. Resistance to erythromycin was most commonly seen, and this is associated with cross-resistance to clindamycin. Among the tetracycline group of drugs, the average MICs to tetracycline was higher than that for doxycycline, which in turn was higher than that for minocycline. Antibiotic resistance can occur with short-term antibiotic courses, and the rate of resistance increases as the duration of antibiotic consumption increases.

Acne Vulgaris↗
PubMed2001

Clinical utility of polymerase chain reaction in the detection of Mycobacterium tuberculosis in different types of cutaneous tuberculosis and tuberculids.

INTRODUCTION: The role of polymerase chain reaction (PCR) in the diagnosis of cutaneous tuberculosis in clinical practice has not been defined as no PCR assay has been tested in a large-scale clinical study. The objective of this study was to test the clinical utility of a PCR assay in the diagnosis of different types of cutaneous tuberculosis and tuberculids. MATERIALS AND METHODS: Analysis of archival biopsy specimens by a nested PCR assay targeting IS6110 of Mycobacterium tuberculosis (M. tb) DNA was performed in a tertiary-care skin hospital in Singapore. PCR results were compared with cultures and concordance with final diagnosis. PATIENTS AND SPECIMENS: One hundred and nineteen skin biopsies from 105 patients comprising 58 cases of confirmed or highly probable cutaneous tuberculosis, ranging from multibacillary infections to paucibacillary forms and 47 cases of possible tuberculids were analysed. Twenty-four subjects with non-tuberculous granulomas and normal skin controls were included. RESULTS: In 14 immunocompromised patients with multibacillary mycobacterial infections (AFB+ on biopsy), PCR was positive in 9 patients. Correlating PCR results with the final diagnosis, the PCR technique was 100% sensitive and specific in this group. In paucibacillary tuberculosis, PCR positivity rates were 55% for tuberculosis verrucosa cutis (38 cases) and 60% for lupus vulgaris (5 cases). When confirmed cases of tuberculosis were considered, the overall sensitivity was 73%. In 26 cases of erythema induratum, PCR was positive in 54% and correlated with a documented response to anti-tuberculous treatment in 80%. CONCLUSIONS: The use of PCR in the routine diagnostic panel for cutaneous tuberculosis should take into consideration the differential sensitivities for different clinical types. In the setting of an immunocompromised patient with AFB+ lesions, PCR has a definite role in rapid diagnosis and in differentiating atypical mycobacterial infection from tuberculosis. Where paucibacillary tuberculosis is suspected, clinical decision should not be based on PCR results alone. In erythema induratum, we found some correlation between PCR results and response to anti-tuberculous therapy.

Base Sequence↗
PubMed2001

Severe diabetes in remission: a Singapore's perspective.

INTRODUCTION: Diabetic ketoacidosis is generally thought to be the classical presentation of individuals with Type 1 diabetes. Clinicians are beginning to see individuals with atypical diabetes presenting with severe hyperglycaemia associated with or without ketosis and after the initial period of intensive insulin therapy, becoming non-insulin dependent and remaining in remission for years. So far, these patients have only been identified amongst African Americans and have only recently been reported amongst the Japanese and the Chinese in Hong Kong. We therefore set out to identify the existence of such patients in our population. MATERIALS AND METHODS: We have a database of patients admitted for diabetic ketoacidosis. From this, we recruited patients who fulfilled the criteria for atypical diabetes and proceeded to perform a retrospective analysis together with a prospective analysis of their outcome. RESULTS: We identified 10 individuals with atypical diabetes with characteristics similar to those previously described. Our data showed that these patients deferred from classical individuals with Type 1 diabetes in the following ways--older age of onset, relatively higher BMI, marked elevation in HBA1c suggesting a significant period and degree of hyperglycaemia and prolonged remission after reversal of hyperglycaemia. CONCLUSIONS: Atypical Type 2 diabetes exists in our population. Clinicians looking after individuals with diabetes should be made aware of this as there are important implications in the subsequent management of such patients.

Adult↗
PubMed2001

Latent autoimmune diabetes in adults (LADA): a case series.

An adult presenting with diabetes is usually assumed to have type 2 diabetes. Since the 1980s, type 2 diabetic subjects who had failed sulphonylurea therapy soon after diagnosis have been thought to be actually slowly progressive type I patients. This diabetes sub-type is currently referred to as latent autoimmune diabetes in adults (LADA). Early recognition of such patients has important clinical implications. To assist local doctors in the recognition of such patients, we performed a retrospective study to profile and highlight distinctive features of thirteen LADA patients. We found that these patients were mostly females with a mean body mass index of 17.2 kg/m2, diagnosed with type 2 diabetes in their fourth decade of life and becoming insulin dependent after a mean of 2.5 years.

Adult↗
PubMed2000

An unusual case of pemphigus vulgaris presenting as bilateral foot ulcers.

We describe an unusual presentation of pemphigus vulgaris, an autoimmune intraepidermal blistering skin disease associated with autoantibodies to the desmosome glycoprotein, desmoglein 3. A 60-year-old man presented with bilateral ulceration on the dorsum of the feet. These clinical features persisted for 4 months before more characteristic signs of pemphigus vulgaris, including mouth ulceration and skin erosions, developed. The atypical presentation led to a delay in diagnosis and initiation of the appropriate treatment. Pemphigus vulgaris may have unusual manifestations, such as nail dystrophy, paronychia, or granulation tissue-like lesions, but this case of bilateral foot ulceration highlights a further, perhaps unique, clinical presentation of this autoimmune disease.

Anti-Inflammatory Agents↗
PubMed2000

Diagnosis of pacemaker lead infection using transoesophageal echocardiography: a case report.

INTRODUCTION: Vegetative lead infection is an uncommon complication of permanent pacemaker implantation. The diagnosis is difficult using conventional imaging methods. CLINICAL PICTURE: An elderly Indian woman with a history of diabetes mellitus developed Staphylococcus aureus infection after implementation of a permanent pacemaker. Following a non-diagnostic transthoracic echocardiogram, transoesophageal echocardiography was performed and showed a large vegetative mass attached to the pacemaker lead within the right atrium. TREATMENT: The pacemaker was removed and intravenous vancomycin administered for six weeks. OUTCOME: She was discharged well but demised two months later from a second episode of septicaemia. CONCLUSIONS: Pacemaker lead infection remains a challenging management problem. Transoesophageal echocardiography can facilitate its diagnosis.

Aged↗
PubMed2000

Toward the differentiation of trust in supervisor and trust in organization.

Trust in supervisor and trust in organization are argued to be distinct but related constructs, each with its own set of antecedents and outcomes. Empirical field results supported the proposition. Although trust in supervisor and trust in organization were positively and significantly correlated, trust in supervisor was more strongly associated with proximal variables (ability, benevolence, and integrity of supervisor), whereas trust in organization was more strongly correlated with global variables (perceived organizational support and justice). This conclusion held despite the inclusion of proximal variables in the regression on trust in organization and the inclusion of global variables in the regression on trust in supervisor. In addition to the differential antecedents of trust in supervisor and trust in organization, the outcomes for both variables were different. Trust in supervisor was related to increased innovative behavior and satisfaction with supervisor, and trust in organization was related to higher organizational commitment and lower intention to leave. Therefore, the authors provide clear preliminary data on the distinctiveness of trust in supervisor and trust in organization. One implication of this set of results is that organizations should adopt a more holistic approach in building trust, which can be achieved by focusing on the various constituents of the organization and the various levels (e.g., the supervisor level and the organizational level).

Humans↗
PubMed2000

Cutaneous leishmaniasis: a report of two cases seen at a tertiary dermatological centre in Singapore.

Cutaneous leishmaniasis (CL) is not common in South-East Asia and often presents as a granulomatous plaque on the exposed areas, with a high index of suspicion required for diagnosis. Two such cases were seen at the National Skin Centre recently, and both were Gurkha men with a history of travel to Belize. They were treated with intravenous sodium stibogluconate with success. A discussion on CL and its management follows.

Adult↗
PubMed2000

Chinese mothers intention to breastfeed, actual achievement and early postnatal experience.

Thirty Chinese primiparous mothers were asked during the antenatal period their breastfeeding intention and then interviewed at delivery and 6 weeks post delivery. One mother had no intention to breastfeed. Ten mothers intended exclusive breastfeeding for one month and 19 for 6 weeks or more. At 6 weeks post delivery only 4 mothers were still breastfeeding. A total of 22 (73%) did not achieve their initial intention. For any future pregnancy, 5 chose exclusive breastfeeding, 22 complementary and 3 formula feeding. Chinese primiparous mothers have high breastfeeding intentions but the majority do not achieve them and their experience has discouraged them from exclusive breastfeeding in future pregnancies.

Asian People↗
PubMed2000

Granuloma annulare: a review of 41 cases at the National Skin Centre.

INTRODUCTION: Granuloma annulare (GA) is a benign, inflammatory skin disorder that has no proven aetiology or widely accepted theory of pathogenesis. We present the results of a local study examining the characteristics of this disorder. MATERIALS AND METHODS: This is a retrospective study of 41 patients with granuloma annulare seen at a tertiary dermatological skin hospital in Singapore. The disease was classified based on whether it was localised or generalised. Remission rates and associated diseases were documented. RESULTS: The majority (93.9%) of lesions were localised. GA tends to occur within the first three decades of life, and 39.4% of patients were 10 years old and below. There was a slight female preponderance, and no predilection for any particular racial group. Remissions were seen in 67.6% of patients who were followed up for at least 12 months, and remissions only occurred with the localised form of GA. There were 4 cases of disseminated GA and 1 case of perforating GA. There were 6 patients with associated diabetes mellitus, 2 with pulmonary tuberculosis, and 4 patients each with hypercholesterolaemia and a history of atopy. CONCLUSION: The characteristics of GA in our local population do not differ significantly from that of overseas studies. While localised forms of GA have a high chance of resolving, the generalised forms of the disease are difficult to treat and do not tend to resolve totally.

Adolescent↗
PubMed1999

Characteristics of bacterial skin infections in children compared to adults at a tertiary dermatologic center.

BACKGROUND: Bacterial skin infections in children and adults are caused by different organisms with different antimicrobial susceptibility. METHODS: A comparative retrospective study was carried out on 233 adults and 53 children with bacterial skin infections. Skin swab cultures and sensitivity tests were performed using standard methods. Statistical analysis was performed using the Pearson chi-squared and Fisher tests. A P value of < 0.05 was considered to be significant. RESULTS: Primary and secondary skin infections occurred in equal proportions in children, whereas secondary skin infections were more common in adults (70.8%). Staphylococcus aureus was the main cause of skin infections, particularly in children (72.6%). S. aureus in children and adults was highly susceptible to cloxacillin, cephalexin, chloramphenicol, neomycin, cotrimoxazole, and clindamycin, moderately susceptible to erythromycin, and insensitive to tetracycline, ampicillin, and penicillin. CONCLUSIONS: It is important to monitor the trends of bacterial infections and their antibiotic susceptibility as this can assist medical practitioners in their choice of antimicrobial therapy. Such monitoring will also help to detect the emergence of resistant bacterial strains and caution us to take care in the use of certain drugs.

Adolescent↗
PubMed1999

Use of ligase chain reaction and polymerase chain reaction on urine specimens to detect Chlamydia trachomatis infections in a sexually transmitted diseases clinic in Singapore.

This study was done to assess the specificity and sensitivity of the DNA amplification assays of ligase chain reaction (LCR) and polymerase chain reaction (PCR) on urine specimens to detect Chlamydia trachomatis infections in both male and female patients seen at a sexually transmitted diseases (STD) clinic in Singapore, compared with other diagnostic methods currently in use. A total of 100 patients were selected; 50 male patients diagnosed with non-gonococcal urethritis based on symptoms and a positive Gram-stained urethral smear and 50 female asymptomatic sex workers were assessed. Automated assays using LCR and PCR were used, and compared to enzyme immunoassays, chlamydial cell cultures and PCR of urethral and endocervical swab specimens. In male patients, LCR and PCR of urine specimens had sensitivities of 100%, compared to 87.0% for PCR of urethral swab specimen, 82.6% for enzyme immunoassay (EIA) and 91.3% for cell cultures. In female patients, LCR and PCR of urine samples achieved sensitivities of 77.8% and 88.9% respectively, compared with 55.6% for PCR of endocervical swab specimens, 22.2% for EIA and 66.7% for cell cultures. LCR and PCR of urine samples provided higher sensitivity compared to cell cultures, EIA and PCR of urethral and endocervical swab specimens. The use of LCR and PCR on urine as a non-invasive means of detecting chlamydial infections is viable, and may have a role to play in population-based screening programmes.

Adult↗