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Biomedical subjects

K C Tan

Publications and source records attributed to K C Tan.

At least 55 records · Page 3Linked to original sources
PubMed2001

Long-term colchicine for recalcitrant palmoplantar pustulosis: treatment outcome in 3 patients.

Palmoplantar pustulosis (PPP) is a chronic, relapsing, pustular eruption affecting the palms and soles for which treatment is often difficult and frustrating. Short-term colchicine has been used to treat PPP with variable response. We report on the successful treatment of 3 patients with severe, therapy-resistant, chronic PPP. We observed significant reduction in the frequency of pustular eruptions and the number of pustules with maximum tolerable doses of colchicine treatment for up to 12 months.

Adult↗
PubMed2000

Extended lower trapezius island myocutaneous flap: a fasciomyocutaneous flap based on the dorsal scapular artery.

The lower trapezius island myocutaneous flap is a useful flap in head and neck reconstruction. It is thin and pliable and can reach defects in most areas of the head and neck. Its usefulness in head and neck reconstruction has often been limited or discouraged by reports of significant failure rates. In this study, the vascular anatomy and clinical use of the extended lower trapezius myocutaneous flap based solely on the dorsal scapular artery system are elucidated, and experience gained performing 20 flaps over the past 5 years by using the extended lower trapezius myocutaneous flap is reported. The vascular anatomy of the dorsal scapular artery system is reviewed in 13 fresh cadaveric dissections by using methylene blue, latex injection studies, and radiologic examination.

Aged↗
PubMed2000

Metabolic and immunologic features of Chinese patients with atypical diabetes mellitus.

OBJECTIVE: To determine whether atypical diabetes mellitus (ADM) is present in the Chinese population in Hong Kong. RESEARCH DESIGN AND METHODS: The records of Chinese patients who attended the Diabetes Clinic at Queen Mary Hospital were reviewed. We identified 11 patients who initially presented with acute diabetic ketoacidosis but subsequently displayed clinical features more typical of type 2 diabetes. Metabolic studies and HLA typing were performed to characterize this group of Chinese patients with ADM. RESULTS: C-peptide response of the patients with ADM 1 h after a standard meal was intermediate between that of type 1 diabetic patients (matched for age and duration of diabetes) and that of nondiabetic control subjects (matched for age and BMI) (analysis of variance, P = 0.02). Insulin sensitivity measured by a short insulin tolerance test was not significantly different between patients with ADM and their matched nondiabetic control subjects. HLA typing showed that none of the patients with ADM had the DR3 allele and that the frequency of DR9 was not increased. Only one patient had significantly increased levels of antibodies to GAD and islet cell antigen 512. CONCLUSIONS: ADM, which was first described in African-Americans, is seen also in Chinese subjects. These patients have significant residual C-peptide secretory capacity and should not be misdiagnosed and treated as patients with type 1 diabetes with life-long insulin therapy.

Adolescent↗
PubMed1999

Effects of fluvastatin on prothrombotic and fibrinolytic factors in type 2 diabetes mellitus.

The effects of fluvastatin therapy on parameters of coagulation and fibrinolysis were evaluated in patients with diabetic dyslipidemia in a randomized, placebo-controlled study. Fluvastatin therapy was associated with a small reduction in factor VII coagulant activity, von Willebrand factor, and in plasminogen activator inhibitor 1 and tissue plasminogen activator antigens, but the effects of fluvastatin on hemostatic factors were much less marked than its effects on plasma lipids.

Analysis of Variance↗
PubMed1999

Roles of hepatic lipase and cholesteryl ester transfer protein in determining low density lipoprotein subfraction distribution in Chinese patients with non-insulin-dependent diabetes mellitus.

Patients with non-insulin-dependent diabetes mellitus (NIDDM) are known to have abnormalities in their low density lipoprotein (LDL) subclass pattern with a preponderance of small dense LDL. The present study was performed to define the roles of lipolytic enzymes (hepatic and lipoprotein lipase) and cholesteryl ester transfer protein (CETP) in determining the distribution of LDL subfractions in these patients. LDL subfractions were measured by density gradient ultracentrifugation in 137 patients with NIDDM (75 male, 62 female) and 140 matched controls (80 male, 60 female). The male diabetic patients had a lower concentration of LDL-I (P < 0.01) and a higher concentration of LDL-III than the controls (P < 0.01). In the female diabetic patients, both LDL-I (P < 0.001) and LDL-II concentrations (P < 0.05) were significantly lower than the controls whereas LDL-III was increased (P < 0.001). Hepatic lipase (HL) was significantly increased in both the male and female diabetic patients (P < 0.01, P < 0.05, respectively) compared to their controls. No significant changes were seen in plasma lipoprotein lipase (LPL) and CETP activity. On multivariate analysis, plasma triglyceride (TG), CETP and HL accounted for 10, 5 and 3% of the variability in LDL-III, respectively, in the diabetic patients (adjusted R2 = 0.18, P = 0.0003). Our findings would support the hypothesis that plasma triglyceride influences LDL particles through a cycle of lipid exchange via the action of CETP. LDL become enriched in triglyceride and are then acted on by HL to produce a population of small dense lipid-poor LDL.

Asian People↗
PubMed1999

HpaII polymorphism in the atrial natriuretic peptide gene and hypertension.

This was an association study of genetic polymorphisms to compare the distribution of the genotypes and alleles of the HpaII polymorphism of the atrial natriuretic peptide (ANP) gene in hypertensive patients and normotensive controls. The setting was an outpatient clinic run by a University Department handling referrals from primary care. The patient cohort was composed of 217 subjects, consisting of 109 healthy controls and 108 patients with newly diagnosed or documented hypertension. The genomic DNA was extracted from peripheral blood leukocytes, amplified by polymerase chain reaction, and digested with the restriction enzyme HpaII. H1 and H2 alleles were identified after electrophoresis. The main outcome measures were to identify the frequencies of ANP genotypes and alleles in hypertensive patients and normotensive controls. The H1H1, H1H2, and H2H2 genotypes occurred in 1%, 19%, and 80% of controls and 3%, 18%, and 80% of hypertensive patients, respectively. The frequencies of the H1 and H2 alleles were 0.11 and 0.89 in controls and 0.12 and 0.88 in hypertensive patients. The frequencies of the ANP genotypes and alleles did not differ significantly between controls and hypertensive patients. Our findings differed from previous reports and suggested that this polymorphism is not associated with hypertension in this population.

Adult↗
PubMed1999

Alterations in hepatic lipase and lipoprotein subfractions with transdermal testosterone replacement therapy.

OBJECTIVES: The effect of sex hormone replacement therapy on lipoprotein metabolism is thought to be less marked with the transdermal route because of the lack of hepatic first-pass effect. The aim of this study was to evaluate the effects of testosterone replacement therapy given transdermally via a permeation-enhanced system on plasma lipolytic enzymes (hepatic and lipoprotein lipase), LDL and HDL subfraction concentrations. MEASUREMENTS: Ten patients with primary testicular failure were started on transdermal testosterone (Testoderm(R)). Plasma lipids, lipoproteins and post-heparin plasma lipolytic enzymes were evaluated before and after 3 months of treatment. LDL and HDL subfractions were measured by density gradient ultracentrifugation and hepatic and lipoprotein lipase activities by radio-enzymatic method. RESULTS: Serum testosterone level increased to within the normal range in all subjects whereas serum dihydrotestosterone (DHT) increased to supra-normal values. Plasma hepatic lipase (HL) activity increased after testosterone replacement (24.7 +/- 7.5 vs. 29.2 +/- 8.3 micromol free fatty acid released per hour, P < 0.05) and the increase in HL correlated with the increase in DHT (r = 0.64, P < 0. 05). Small changes were observed in LDL subfraction pattern with an increase in the concentration of small dense LDL-III (80.1 +/- 30.3 vs. 93.0 +/- 27.8 mg/l, P < 0.05). No significant change was seen in the HDL2 subfraction but HDL3 decreased after treatment (0.93 +/- 0. 17 vs. 0.79 +/- 0.14 mmol/l, P < 0.01). CONCLUSIONS: Testosterone replacement, given via a permeation-enhanced transdermal system, is associated with changes in hepatic lipase activity and in LDL and HDL subfractions. Whether these changes adversely influence the cardiovascular risk in the longterm remains to be determined.

Administration, Cutaneous↗
PubMed1999

Detection of Mycobacterium tuberculosis DNA using polymerase chain reaction in cutaneous tuberculosis and tuberculids.

BACKGROUND: The objective of this study was to explore the role of the polymerase chain reaction (PCR) fo the detection of Mycobacterium tuberculosis DNA as a diagnostic aid in cutaneous tuberculosis using routinely processed skin biopsy specimens. METHODS AND RESULTS: A wide range of clinical specimens representing different forms of cutaneous tuberculosis and so-called tuberculids were studied. A sensitive and specific PCR assay targeting the sequence IS6110 of Mycobacterium tuberculosis complex was used. The specimens were categorized as follows. 1 Acid-fast bacilli (AFB) positive on biopsy (nine specimens from seven patients who were immunocompromised). PCR was positive in five specimens. Of these, one specimen was culture positive and three specimens were culture negative. 2 AFB negative on biopsy: (a) tuberculosis verrucosa cutis (23 specimens); (b) lupus vulgaris (three specimens); (c) cutaneous tuberculosis clinically suspected (six specimens). PCR was negative in all specimens. 3 Tuberculids.' (a) erythema induratum/nodular vasculitis (20 specimens); (b) papulonecrotic tuberculid (two specimens); (c) erythema nodosum (20 specimens). PCR was negative in all specimens. CONCLUSIONS: The role of PCR in clinical dermatologic practice, at this stage, may be in differentiating between cutaneous tuberculosis and atypical mycobacterial infections in the context of an immunocompromised patient where AFB can be demonstrated on biopsy and cultures may be negative. In this clinical situation, PCR allows the prompt diagnosis and early institution of appropriate therapy. We have not found PCR to be a useful complement to the clinical and histologic diagnosis of "paucibacillary" forms of cutaneous tuberculosis.

Adult↗
PubMed1999

7Alpha-methyl-19-nortestosterone maintains sexual behavior and mood in hypogonadal men.

The synthetic steroid 7alpha-methyl-19-nortestosterone (MENT) is a potent androgen that is resistant to 5alpha-reductase. It thus has decreased activity at the prostate and may have advantages over testosterone-based regimens in long term treatment or as part of a male contraceptive. Administration to eugonadal men results in suppression of gonadotropins, but its ability to support androgen-dependent behavior has not been investigated. For sustained release administration, MENT acetate was used, because its diffusion characteristics were more suitable for use in implants. However, upon release the acetate is rapidly hydrolyzed, and MENT is the biologically active moiety in circulation. We studied the effects of MENT on sexual interest and activity, spontaneous erection, and mood states in comparison with testosterone enanthate (TE) in 20 Caucasian and Chinese hypogonadal men recruited in Edinburgh and Hong Kong (n = 10 in each center). Outcomes were measured using a combination of daily diaries, semistructured interviews, and questionnaires. Nocturnal penile tumescence (NPT) was also recorded in the Edinburgh group. After withdrawal of androgen replacement treatment (wash-out phase) for a minimum of 6 weeks, subjects were randomized to two groups in a cross-over design. Drug treatment regimens were of 6-week duration and consisted of two implants, each containing 115 mg MENT acetate, inserted s.c. into the upper arm and removed after 6 weeks and two injections of TE (200 mg, i.m.) 3 weeks apart. MENT treatment resulted in stable plasma MENT concentrations of 1.4 +/- 0.1 nmol/L after 3 weeks and 1.3 +/- 0.1 nmol/L after 6 weeks (mean +/- SEM; all men). Nadir testosterone concentrations were 3.6 +/- 0.6 nmol/L at the end of the wash-out phase and 9.4 +/- 0.6 nmol/L 3 weeks after each injection. There were no differences in hormone concentrations between centers. There were no adverse toxicological effects. There were only minor differences between the two treatments. Both MENT and TE treatment resulted in significant increases in sexual interest and activity, spontaneous erection (both by self-report and NPT measurement), and increases in positive moods, with decreases in negative moods in the Edinburgh group. In the Hong Kong group, both treatments increased waking erection, with a trend toward increased sexual interest and activity. Mood states appeared to be less affected during the wash-out phase than in Edinburgh men and showed no significant response to either treatment. These results demonstrate that MENT has similar effects on sexual activity and mood states as testosterone in hypogonadal men. As NPT is a physiological androgen-dependant outcome, these data provide further evidence for the androgenicity of MENT. The lack of detected effect of either androgen in Hong Kong men other than on waking erection illustrates the importance of the cultural context of symptomatology and its measurement. The appropriate dose of MENT remains to be determined, but these results support its development as a potential androgen replacement therapy.

Adult↗
PubMed1999

Influence of low density lipoprotein (LDL) subfraction profile and LDL oxidation on endothelium-dependent and independent vasodilation in patients with type 2 diabetes.

Recent studies have suggested that hypercholesterolemia is associated with endothelial dysfunction. In patients with type 2 diabetes mellitus, dyslipidemia is mainly characterized by hypertriglyceridemia, low high density lipoprotein, and a preponderance of small dense low density lipoprotein (LDL) particles. We have examined the relationships among LDL subfractions, the susceptibility of LDL to oxidation in vitro, and endothelial function in type 2 diabetes mellitus. LDL subfractions were measured by density gradient ultracentrifugation. The susceptibility of LDL to oxidation was determined by measuring the kinetics of conjugated dienes formation during copper-mediated oxidation of LDL. Endothelium-dependent and independent vasodilation of the brachial artery were assessed by high resolution vascular ultrasound. Diabetic patients had a higher concentration of small dense LDL-III than matched controls (P < 0.01). The lag phase of conjugated dienes formation was shorter in the diabetic patients (P < 0.05), and the rate of LDL oxidation was faster (P < 0.05). Both endothelium-dependent (P < 0.01) and independent dilation of the brachial artery (P < 0.01) were impaired in the diabetic patients. On multivariate analysis, the rate of oxidation and LDL-III concentration accounted for 12% and 6%, respectively, of the variation in endothelium-dependent vasodilation (adjusted r2 = 0.18; P < 0.05), whereas LDL-III concentration and the maximum amount of conjugated dienes formed accounted for 27% and 5%, respectively, of the variation in endothelium-independent vasodilation (adjusted r2 = 0.32; P < 0.01) in the diabetic patients. In conclusion, endothelial and smooth muscle cell dysfunction in type 2 diabetes were related to abnormalities in LDL subfractions and in LDL oxidation.

Adult↗