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Biomedical subjects

H H Tan

Publications and source records attributed to H H Tan.

At least 55 records · Page 3Linked to original sources
PubMed1999

Activated protein C resistance: a study among 60 thromboembolic patients in the Singapore population.

Resistance to activated protein C (APC-R) is the commonest inherited cause of thrombosis among Caucasians. Few studies have been carried out on its prevalence in Asians. We conducted a prospective study on 60 patients with thromboembolism to determine its prevalence in our local population. The Factor V Leiden (VaQ506) mutation associated with this condition was detected by amplification of the Factor V gene by polymerase chain reaction (PCR) and digestion of the fragment with Mnl I. Three patients were found to be heterozygous for this mutation. None of the 3 patients had other concomitant hypercoagulable states. In addition, we studied the prevalence of this condition in Malays which was found to be 0.5%. Our study suggests that the incidence of APC-R is much lower here compared to the West.

Activated Protein C Resistance↗
PubMed1999

An open label comparative study of azithromycin and doxycycline in the treatment of non-gonococcal urethritis in males and Chlamydia trachomatis cervicitis in female sex workers in an STD clinic in Singapore.

AIM OF STUDY: The aim of this study was to compare the clinical and microbiological efficacy of a single 1 gram dose of azithromycin against 1 week of doxycycline at 100 mg twice a day in the treatment of: (1) uncomplicated non-gonococcal urethritis (NGU) in male patients, and (2) culture proven Chlamydia trachomatis cervicitis in female sex workers. METHOD: The subjects were 53 male patients who attended the clinic and were diagnosed to have non gonococcal urethritis based on clinical symptoms and a urethral smear, and 63 female sex workers, who had both a positive enzyme immunoassay (EIA) test and Chlamydia trachomatis cultures. Follow-up visits were made at one and two weeks post-treatment to assess efficacy, subsequent relapse and presence of side effects. The male patients were also assessed at four weeks post treatment to determine default and reinfection rates. RESULTS: Both azithromycin (clinical cure rates 62.5% at one week, 86.4% at two weeks in male patients; 96.6% at two weeks in female sex workers) and doxycycline (clinical cure rates 65.4% at one week, 90.9% at two weeks in male patients; 100% at two weeks in female sex workers) were effective in treating non-gonococcal urethritis and chlamydial cervicitis. Both drugs were very effective in eradicating proven Chlamydia trachomatis infections, with success in 100% of cases of Chlamydia trachomatis NGU in males, and 96.6% and 100% cure rates, for azithromycin and doxycycline respectively, in female sex workers with cervicitis. There were no statistically significant differences between the two drugs in terms of clinical efficacy, influence on default rates or subsequent risk of reinfection. CONCLUSIONS: We conclude that a single dose of azithromycin is as effective as a one week course of doxycycline in treating non-gonococcal urethritis in males and in the elimination of Chlamydia trachomatis in females with cervicitis, with the added advantage of a convenient single dose that can be supervised.

Adolescent↗
PubMed1999

Autologous transfusion in obstetrics.

AIM OF STUDY: To assess the safety of blood collection for autologous transfusion in pregnant women and the effects of the procedure on the fetus. METHOD: Prospective study involving obstetric patients undergoing elective lower segment Caesarean section (LSCS) between 1993 and 1994 were recruited for autologous transfusion. Continuous cardiotocograph monitoring was carried out throughout the duration of the procedure and the fetal haemodynamics was studied before and after by doppler blood flow ultrasound. RESULTS: The results show that there was no fetal deceleration or increased uterine activity as monitored by cardiotocography. The mean pulsatility index (PI) for the umbilical artery before the procedure was 0.9560 and after was 0.0820 which is a significant difference (p value = 0.035). CONCLUSION: Autologous blood collection seems to be a safe procedure for both the mother and the fetus. However, autologous transfusion remains an unpopular choice amongst pregnant women.

Adult↗
PubMed1998

Juvenile xanthogranuloma and neurofibromatosis 1.

A case of juvenile xanthogranuloma associated with neurofibromatosis type 1 in a 9-month-old Chinese boy is presented. The literature concerning the association between these two conditions and juvenile chronic myelogenous leukaemia is highlighted. The patient presently has no evidence of any haematological malignancy, but requires close follow-up.

Diagnosis, Differential↗
PubMed1998

Bacterial skin infections at a tertiary dermatological centre.

BACKGROUND: Bacterial skin infections are common clinical problems encountered in most fields of clinical medicine. Staphylococcus aureus and group A streptococci are common invaders of eczematous, traumatised or immunocompromised skin. Advances in pharmacology have introduced a wide array of new antibiotics into the physician's armamentarium, but the rising incidence of bacterial resistance continues to be a problem. A retrospective study was carried out on 331 patients at the National Skin Centre, Singapore, to establish the causes of common primary and secondary pyodermas, as well as to determine the antibiotic sensitivities of the microorganisms responsible. METHODS: A retrospective study of the medical records of 331 patients seen at the Centre for skin infections between October 1995 and May 1996 was done. Skin cultures and antibiotic sensitivity testing was carried out and the data analysed. Both primary pyodermas (impetigo, folliculitis, furuncles/carbuncles and cellulitis) and secondary pyodermas (infected ulcers and infected eczemas) were included. The results of bacterial isolation cultures and sensitivity of the organisms isolated to the commonly used antibiotics such as cloxacillin, penicillin, erythromycin and the tetracyclines were analysed. RESULTS: Staphylococcus aureus was the commonest organism isolated from both primary and secondary pyodermas, accounting for 67% and 46.7% of the organisms isolated, respectively. There was no significant difference in the racial representation in each of the various skin infections, but there was a significantly greater female representation in the infected ulcers. The secondary pyodermas had a significantly higher incidence of gram negative organisms causing infections, as well as culture results showing multiple bacterial pathogens. The methicillin resistant strains of S. aureus were commoner in the secondary pyodermas, and accounted for 4.2% of the total organisms isolated and 7% of the total strains of S. aureus. The S. aureus had a high rate of resistance (89.5%) to penicillin and ampicillin, but was very sensitive (93%) to cloxacillin, cephalexin and cotrimoxazole. The incidence of erythromycin resistance was 18.7%. CONCLUSIONS: In patients with primary pyodermas, cloxacillin should be the first line antibiotic used, with erythromycin as a useful but less preferred alternative. The favoured combination of ampicillin and cloxacillin has little place in routine treatment of skin infections, except for cellulitis and infected eczemas. A cephalosporin can also be used in these conditions if single drug therapy is desired. The secondarily infected ulcers are difficult to treat and would probably require the use of combination therapy in view of frequent mixed infections.

Adolescent↗
PubMed1997

Bilateral lower limb oedema due to a distended urinary bladder.

A 91-year-old Chinese man developed bilateral lower limb oedema due to venous obstruction resulting from a distended urinary bladder. After the bladder was decompressed by urethral catheterisation, the bilateral lower limb oedema promptly subsided. Although a distended urinary bladder is a rare cause of bilateral lower limb oedema, it can be easily recognised by palpation of the lower abdomen and the relief of symptoms by urethral catheterisation is most rewarding.

Aged↗
PubMed1997

Occupational skin disease in workers from the electronics industry in Singapore.

Of 149 workers from the electronics industry with occupational dermatoses seen at the Joint Occupational Dermatoses Clinic at the National Skin Centre, Singapore, 51.0% (76) were diagnosed to have irritant contact dermatitis, 40.9% (61) had allergic contact dermatitis, and 8.1% (12) had noncontact dermatitis. More than half of the patients were younger than 30 years of age. Common irritants were soldering flux, oils and coolants, solvents, and acids/alkalis. The most common allergens were nickel and resins, followed by rubber chemicals and the constituents of flux. Of the noncontact dermatitis, 8 were caused by occupationally relevant exacerbation of endogenous eczema, whereas there was one case each of miliaria, frictional dermatitis, and fatal toxic epidermal necrolysis caused by trichloroethylene allergy.

Adult↗
PubMed1997

Familial aplasia cutis congenita of the scalp: a case report and review.

We report three cases of aplasia cutis congenita of the scalp affecting two siblings and their mother, suggesting group 1, or autosomal dominant aplasia cutis congenita not associated with multiple abnormalities. A review of the clinical features and literature concerning this heterogenous and rare condition is presented.

Alopecia↗
PubMed1996

Cutaneous gangrene secondary to metastatic calcification in end stage renal failure--a case report.

Metastatic calcification is a frequent association of chronic renal failure but skin involvement is accepted as a rare, albeit well recognised, complication accompanying the secondary hyperparathyroidism that results from renal impairment, although the aetiology remains unknown. Skin involvement can take the form of metastatic calcinosis cutis or cutaneous gangrene resulting from vascular calcification. There have been reported cases which describe the healing of gangrenous areas following parathyroidectomy as well as use of dietary restriction of phosphorus and phosphate binding antacids(1-6). We report a case of a 35-year-old man with end stage renal failure who presented with cutaneous gangrene but who eventually succumbed despite a subtotal parathyroidectomy and review some of the literature concerning this subject.

Adult↗
PubMed1995

Transurethral microwave thermotherapy (TUMT) for benign prostatic hyperplasia (BPH)--our first 100 cases.

One hundred consecutive cases treated by Transurethral Microwave Thermotherapy (TUMT) since October 1991 were analysed to assess its efficacy and safety. Out of these, 28 were in urinary retention. Patients were selected based on Madsen Symptom Score (MSS), Uroflowmetry, Transrectal Ultrasound Scanning (TRUS) plus biopsy and flexible cystoscopy. In the non-retention group, symptomatic improvement was 81%; mean MSS dropped from 13.6 to 2.6 at one year. Objective improvement was less marked: mean peak urine flowrate (PFR) (+45%), mean residual volume (-63%) and mean prostatic volume (-15%). 8.3% had failed TUMT requiring TURP. In the retention group, 79% was able to void freely after TUMT. Fourteen percent underwent TURP. Based on given criteria, the overall response rate for MSS and PFR averaged 71% at 3 months, 72% at 6 months and 84% at 1 year. Sixty-seven percent of patients who responded to a phone interview were satisfied with TUMT treatment. Minimal morbidity was encountered: temporary retention for non-retention group (24%), UTI (9%), haematuria (7%), impotence (2%) and fistula (1%). There was no treatment-related death. The results showed that TUMT is a viable alternative and safe treatment of BPH.

Adult↗
PubMed1995

Use of prostate specific antigen (PSA) and transrectal ultrasound (TRUS) in the diagnosis of prostate cancer--a local experience.

Prostate specific antigen (PSA) and transrectal ultrasound (TRUS) are two new modalities added to improve our ability to diagnose prostate cancer at an early stage. We reviewed our own experience of 100 cancers among 579 men from August 1991 to October1994. The detection rate was 17.3%. Digital rectal examination (DRE) alone had a positive predictive value (PPV) of 39.9%. The PPV for PSA was 23%. The combination of PSA and DRE gave a PPV of 47.2%. TRUS had a PPV of 30.6%. Features of cancer on TRUS may be both hypoechoic or hyperechoic nodules which appeared to have almost equal proportions associated with cancer. The addition of age-specific ranges did not affect the PPV of PSA. The PPV of the combination of TRUS and DRE was 53%. With all 3 modalities combined, the PPV was 58.8%. An interesting finding from the study was the higher average PSA for benign and malignant disease in the local population and cases of acute retention of urine. There was a higher incidence of prostatitis and lower incidence of cancer in cases with retention of urine.

Adult↗
PubMed1995

Transrectal ultrasound in male infertility.

In the evaluation of the subfertile man who has severe oligospermia or azoospermia associated with a low volume ejaculate, the high resolution transrectal ultrasound (TRUS) has, in recent years, been a very important non-invasive imaging technique to detect abnormalities in the seminal vesicles, ejaculatory duct and the status of the prostate. We performed TRUS in 30 of these patients from January to December 1994 followed by scrotal exploration with vasogram using methylene blue, inspection of the epdidymis for dilatation and fibrosis together with testicular biopsy to evaluate testicular spermatogenesis and obstruction. Of the 30 patients, 11 were found to have dilated vesicles or ejaculatory duct obstruction. Three had features of prostatitis with calcification or thickened wall of the vesicles and one had an absent vesicle and vas. The remaining 15 patients had normal seminal vesicles and ejaculatory ducts on TRUS and their testicular biopsies showed atrophy, fibrosis or maturation arrest. Transurethral resection of the ejaculatory duct (TRU-ED) under TRUS guidance was done for 10 patients with dilated seminal vesicles and 6 of them had normal semen analysis 3 months after operation. Two successful pregnancies were achieved.

Adult↗
PubMed1991

Transrectal ultrasound of the prostate: the early Singapore experience.

During a four-month-period 40 patients presenting to the Department of Urology with mainly retention of urine had their prostates scanned ultrasonically. Eight nodules were detected on the ultrasound of which five were not detected on digital rectal examination. Of the five non-palpable nodules two were diagnosed on ultrasound guided transperineal Tru-cut biopsy to be carcinomas. Of the three nodules detected both on ultrasound and digital rectal examination, two were proven to be carcinomas while the other was benign. The transrectal ultrasound was not only found to be easy to use but was also found to be a useful complement to the urologist's index finger with the added advantage of obtaining good quality biopsy material from suspicious lesions.

Aged↗
PubMed1991

[Marketing: an instrument in transforming health care to health service].

Due to historical developments emphasis in thinking and acting in dentistry was placed on providing care. Changes in society and dentistry resulted in a greater patients' independence and in an increased demand for service. Marketing enables to cope with the transformation of care into service and improves efficiency and quality.

Humans↗
PubMed1990

Job satisfaction among stayers and leavers of dental group practices in The Netherlands.

Working in group dental practices has increased during the last few decades. In the present study all the dentists (n = 82) who had participated in group practices in the Netherlands for at least 10 years were interviewed and questioned about the nature of their practices, their working conditions and their 'job satisfaction'. Most of them (78 per cent) had a second appointment, besides that in the group practice. During the past 10 years 32 per cent of the dentists had left the group practice because of personal conflicts, the wish to change to solo practice or a different appointment, organisational problems, or dissatisfaction with practice space. Eighty-two per cent of them declared that they were, in general, (very) satisfied with their work; these included 94 per cent of the 'stayers' and 63 per cent of the 'leavers'. The main motives for joining a group practice rather than working in a solo practice were: being less isolated, having the possibility of mutual consultation, the stimulation of working with colleagues, and the more efficient use of staff and equipment. These motives were satisfactorily realised, according to the 'stayers'; and 'leavers' scored less favourably, but still at a high level. The same picture was also seen in the other features studied; the 'stayers' were very satisfied with their working conditions and the future possibilities of the group practice, while the 'leavers' reacted less positively, but, on average, not negatively.

Group Practice, Dental↗
PubMed1989

[Knowledge of dental treatment in the Dutch population].

A survey in an at random sample of 18-66 years old persons was conducted in the Netherlands to assess knowledge of dental treatment possibilities. The results show that 29% has an inadequate level of knowledge, 54% a moderate level and 17% a good level. With regard to the dental subjects, it turns out that knowledge was good on preventive items while a poor knowledge score was found on items of oral surgery and aesthetic dentistry. People without a dentist, with lower income and occupation have less knowledge than people that report having a dentist, a higher income and a higher occupation. The occupation has the largest effect on the knowledge score.

Attitude to Health↗