PubMed Health⌕ Search

Biomedical subjects

H S Tang

Publications and source records attributed to H S Tang.

At least 19 recordsLinked to original sources
PubMed2006

Denaturing HPLC for high-throughput screening of rifampicin-resistant Mycobacterium tuberculosis isolates.

OBJECTIVE: To evaluate the use of denaturation high-performance liquid chromatography (dHPLC) as a rapid method to detect rifampicin (RMP) resistance based on mutations in the rpoB gene in a high-volume laboratory setting. METHODS: A total of 132 RMP-resistant Mycobacterium tuberculosis strains with different rpoB mutation were used to optimise the running condition of dHPLC as a pilot study. A blind correlation study was subsequently done between dHPLC and in vitro RMP susceptibility tests on 3167 M. tuberculosis strains in a high-throughput clinical setting. RESULTS: In the pilot study, rpoB mutation could be detected on 116/132 (87.9%) RMP-resistant strains by dHPLC. In the second phase of the study, 84/3107 (2.7%) clinical M. tuberculosis isolates were RMP-resistant. The sensitivity and specificity of dHPLC in the prediction of RMP resistance were 70/84 (83.3%) and 70/77 (91.0%), respectively. The specificity became 100% when 511 Leu to Pro mutation was excluded from the RMP resistance-related genetic changes. CONCLUSION: In the detection of RMP resistance in a high-throughput laboratory setting, dHPLC has been demonstrated to be rapid, simple, workable, automatable and inexpensive in terms of running costs and the labour involved.

Bacterial Proteins↗
PubMed2001

The Chinese version of the Davidson Trauma Scale: a practice test for validation.

The Chinese version of the Davidson Trauma Scale (DTS-C) was developed to respond to the need of Chinese-speaking individuals. The DTS is a validated self-rating scale used in the diagnosis of posttraumatic stress disorder (PTSD). The DTS-C is translated from DTS through a two-stage translation. Subjects were drawn from a sample of 210 survivors of the 21 September 1999, Chi-Chi Earthquake. The scale showed good internal consistency (Cronbach's alpha = 0.97) and test-retest reliability (r = 0.88). Concurrent validity was obtained against the clinical diagnostic interview, with a diagnostic accuracy of 0.85 at DTS-C score of 44. It showed that the sensitivity was 0.9, specificity 0.81, positive likelihood ratio 4.74, and negative likelihood ratio 0.12. The recommended stratum-specific likelihood ratios were 0.10 (95% CI: 0.05-0.20) for the score range 0-39, 4 (2.22-7.23) for the score range of 40-59, and 6.14 (3.42-11.02) for the scores above 60. In PTSD diagnosed subjects, the factor structures closely resembled the DSM-IV grouping of PTSD symptoms. The psychometric strength of DTS-C is reliable for its future use, particularly for screening for subjects with possible diagnosis of PTSD.

Adolescent↗
PubMed1999

Factors predicting local recurrence of desmoid tumours including proliferating cell nuclear antigen.

BACKGROUND: A series of 24 patients with desmoid tumours were studied to determine factors predicting local recurrence, and to establish whether these desmoid tumours were oestrogen receptor-positive or -negative. METHODS: Histology was reviewed and immunohistochemical studies were undertaken. Risk factors for local recurrence were analysed. RESULTS: The findings indicate that the 24 desmoid tumours were oestrogen receptor- and progesterone receptor-negative. Most tumours were proliferating cell nuclear antigen (PCNA)-positive, and positivity was graded by percentage of cells staining and the intensity of the staining. The presence of incomplete macroscopic or histological surgical resection margins did not correlate with local recurrence. Although all tumours that recurred were strongly PCNA-positive with a high percentage of positive cell staining, this trend was not significant. Local recurrence was more common in desmoid tumours arising in extra-abdominal sites (P = 0.03). Extra-abdominal desmoid tumours were significantly more likely to have incomplete histological margins following resection (P < 0.05). CONCLUSION: Desmoid tumours are oestrogen receptor- and progesterone receptor-negative. Of factors analysed for local recurrence, only the extra-abdominal site was significant.

Adult↗
PubMed1998

Novel single-point plasma or saliva dextromethorphan method for determining CYP2D6 activity.

O-Demethylation of dextromethorphan co-segregates with 4-hydroxylation of debrisoquin and is used for CYP2D6 phenotyping. In most previous studies, 8-h urinary samples were collected for determining the dextromethorphan metabolic ratio (dextromethorphan/dextrorphan molar ratio). In addition, a salivary sampling at 3 h had been suggested for the phenotyping. To evaluate the repeatability and validity of previously reported and other potential phenotyping methods, we determined the metabolic ratios from urine samples (for various intervals), or from plasma or saliva (at varying time points) after repetitive single doses of immediate-release or repetitive multiple doses of controlled-release dextromethorphan preparations. For the single-dose study, each of 12 subjects received 15 mg of immediate-release dextromethorphan in period I and period II, respectively, with a 1-week washout period. For the multiple-dose study, each of 16 subjects received 60 mg controlled-release dextromethorphan twice daily for 5 days in period I and period II, respectively, with a 2-week washout period. Dextromethorphan and dextrorphan were assayed by high-performance liquid chromatography. In the single-dose study, most metabolic ratios revealed good repeatabilities for the two periods (paired t test). The metabolic ratio from urine collected for 4 h, 6 h, 8 h or 12 h from plasma at any time between 1 h and 5 h or at 8 h, or from saliva at 2 h or 6 h, could reflect that from 0- to 24-h urine or AUCinfinity. In the multiple-dose study, all metabolic ratios revealed good repeatabilities. The plasma metabolic ratio at any time between 0.5 h and 10 h or the saliva metabolic ratio at any time between 3 h and 12 h, but not the urine metabolic ratio from any interval, could predict the metabolic ratio from ACUSStau. The 2 h, 3 h, 4 h or 5 h plasma metabolic ratio and 6 h saliva metabolic ratios after a single dose correlated significantly with their corresponding multiple-dose metabolic ratio (r > 0.8, P < .05). In conclusion, the plasma sample at 2 h, 3 h, 4 h or 5 h or the saliva sample at 6 h in either the single immediate-release (15 mg) or the multiple controlled-release dose (60 mg) procedure could be used for determining the dextromethorphan metabolic ratio.

Adult↗
PubMed1997

Alcoholism and alcoholic organ damage and genetic polymorphisms of alcohol metabolizing enzymes in Chinese patients.

It is still not clear why some alcoholic patients acquire certain organ-specific complications of alcoholism whereas other alcoholic patients acquire different ones. As we know the liver alcohol dehydrogenase (ADH), aldehyde dehydrogenase (ALDH), and cytochrome P4502E1 (P4502E1) are polymorphic at the ADH2, ADH3, and ALDH2 loci and the 5'-flanking region of the P4502E1. The aim of this study was to investigate the differences between Chinese alcoholic patients with cirrhosis and acute pancreatitis by studying the genetic polymorphisms of ADH2, ADH3, ALDH2, and P4502E1. Genotyping of ADH2, ADH3, ALDH2, and P4502E1 was performed using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) methods on peripheral white blood cell DNA from 75 alcoholic cirrhotic patients, 48 acute alcoholic pancreatitis patients, 19 heavy drinkers without liver disease or pancreatitis, and 235 controls. The results showed that the frequencies of the alleles ADH2*1 and ALDH2*1 in the alcoholic cirrhotic patients were significantly higher than those in the nonalcoholic controls. In acute alcoholic pancreatitis patients, only the frequency of allele ALDH2*1, not ADH2*1 was significantly higher than in the nonalcoholic controls. The allele frequency of ADH2*1 in acute pancreatitis patients was significantly lower (P < .01) than in alcoholic cirrhotic patients. The daily amount of alcohol consumption was significantly lower in patients with acute pancreatitis than in patients with cirrhosis (P < .0005). The genotype distributions of P4502E1, detected by RsaI and PstI, were not different among alcoholic cirrhotic patients, alcoholic pancreatitis patients, heavy drinker, and nonalcoholic controls. In conclusion, ALDH2*1 is the most important alcohol metabolizing gene affecting predisposition to alcoholism whereas the ADH2*2 gene may influence susceptibility to acute alcoholic pancreatitis. The patients with alcohol-induced cirrhosis and with alcohol-induced acute pancreatitis are of two different subpopulations.

Acute Disease↗
PubMed1997

Detection of alphafetoprotein-expressing cells in the blood of patients with hepatoma and hepatitis.

The presence of tumour cells in the blood circulation may predict disease recurrence and metastasis. We have evaluated the specificity and sensitivity of detecting hepatoma cells in blood using nested polymerase chain reaction with primers specific for the alphafetoprotein (AFP) gene. The nested polymerase chain reaction amplified a 270-base pair AFP DNA fragment from cDNA of Hep 3B hepatoma cells. In a reconstitution experiment, AFP mRNA was detected from peripheral mononuclear cells isolated from 10 ml of blood containing as few as ten Hep 3B cells. Peripheral mononuclear cells from the blood of 20 hepatoma patients were analysed, and 19 patients showed positive AFP mRNA expression. Seven of 13 samples from hepatitis patients also showed positive AFP mRNA expression. All five paired samples of peripheral blood or umbilical cord blood from pregnant mothers and their babies, respectively, showed positive AFP expression. None of 22 control samples was positive. The presence of AFP mRNA in the blood of hepatitis or hepatoma patients suggests the presence of circulating hepatoma cells or hepatocytes in the circulation. The high incidence of AFP mRNA in the blood of hepatoma patients supports the notion of early haematogenous spreading of the disease.

Feasibility Studies↗
PubMed1996

Soluble CD44 isoforms in serum as potential markers of metastatic gastric carcinoma.

A splice variant of CD44 (exon V4-V7) confers metastatic behavior in a rat carcinoma model; aberrant expression of splice variants has been detected on a variety of human tumor cell lines as well as primary and metastatic human tumors, including lymphomas, carcinomas (colon, thyroid, mamma, bladder), and glioma. We used enzyme-linked immunosorbent assay to determine the concentration of soluble CD44 in the serum samples of 10 normal individuals and 41 patients with various stages of gastric cancer. Soluble CD44S and its isoforms, V5 and V6, were present in the serum of normal individuals (288.53 +/- 18.33, 25.49 +/- 1.70, and 148.32 +/- 3.15 ng/ml, respectively). The concentrations of soluble CD44 V5 and V6 were elevated in patients with advanced gastric carcinoma (69.39 +/- 6.06 and 216.62 +/- 32.98 ng/ml, respectively). Serum CD44 V5 concentrations correlated with the extent of tumor invasion (T), the status of lymph node involvement (N), and distant metastasis (M) (TNM staging) (p < 0.05), whereas CD44S did not. These results suggest that detection of abnormal regulation of CD44 splicing could be helpful in gastric cancer diagnosis and disease evaluation.

Biomarkers, Tumor↗
PubMed1996

A rare case of multiple intussusceptions: intense segmentary lipomatosis of the ileum.

We report a patient who presented with intestinal obstruction; his small intestine showed intense segmentary lipomatosis associated with unusually situated multiple intussusceptions. Preoperatively, we diagnosed intussusceptions in the ileocecal region by ultrasonography and computed tomographic scan. During surgery, the ileum was dilated and contained numerous movable polypoid masses. One reducible intussusception was encountered in the ileocecal region. In addition, an ileoileal intussusception that could not be reduced was resected with an end-to-end anastomosis. At histological examination, more than 150 submucosal lipomas were found.

Adult↗
PubMed1996

Hydatid cysts in the liver.

A 67-year-old Taiwanese woman with multilocular hydatid cysts of the liver presented with a 5-month history of intermittent right upper abdominal discomfort. Abdominal ultrasonography and computed tomography showed multiple cysts in both lobes of the liver. Subsequent selective celiac angiography revealed an avascular space-occupying lesion in the right lobe. She underwent a radical excision of the cyst by total closed (without opening the wall) cystopericystectomy over segments 4, 5 and 6. Histologic study of the lesions showed three structural components: 1) an outer acellular laminated membrane, 2) a thin nucleated germinal membrane and 3) several protoscolices with Echinococcus granulosus suckers. The patient has been well for 5 years since her discharge. Although hydatid cysts of the liver are extremely rare in Taiwan, they may cause life-threatening complications and mortality. Making a preoperative diagnosis is important and is only possible if this rare disease is kept in mind.

Aged↗