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Biomedical subjects

T L Wu

Publications and source records attributed to T L Wu.

At least 19 recordsLinked to original sources
PubMed2005

Correlations of androgen deficiency with clinical symptoms in Taiwanese males.

The purpose of this study was to elucidate correlations between different biochemical measurements of androgen deficiency and clinical symptoms in male residents of Taiwan. An investigation of the serum biochemical markers for androgen deficiency in 650 males, including total testosterone, calculated free testosterone, and bioavailable testosterone, was conducted. Measurements of clinical symptoms were obtained using a questionnaire of the androgen deficiency in the aging male (ADAM) by St Louis University (SLQ). Correlations among the biochemical markers, correlations of the biochemical markers and age, and relationships between the biochemical markers and the SLQ were evaluated. The sensitivity and specificity of the SLQ were determined. Bioavailable and calculated free testosterone correlated better with age than did total testosterone. Eighty percent of the men had a positive SLQ, and 20% had a negative SLQ. The percentage of positive SLQ results increased with age. No statistically significant difference was noted between the biochemical markers of bioavailable and calculated free testosterone levels and the SLQ status except for men aged over 70 years. The SLQ in this study showed an acceptable sensitivity of about 80%, but the specificity was poor (about 20%). In conclusion, bioavailable testosterone and calculated free testosterone were more-closely correlated with age and may be better biochemical markers for androgen deficiency. SLQ might not be a suitable single measurement for androgen deficiency and should be used together with biochemical markers.

Adult↗
PubMed2004

Isolation of Salmonella enterica serotype choleraesuis resistant to ceftriaxone and ciprofloxacin.

Salmonella enterica serotype choleraesuis (S choleraesuis) usually causes systemic infections in man that need antimicrobial treatment. We isolated a strain of S choleraesuis that was resistant to ceftriaxone and ciprofloxacin from a patient with sepsis. Ciprofloxacin resistance was associated with mutations in gyrA and parC, whereas the ampC gene (bla(CMY-2)), responsible for ceftriaxone resistance, was carried by a transposon-like mobile element. This element was found inserted into finQ of a potentially transmissible 140 kb plasmid, with an 8 bp direct repeat flanking the junction regions. The appearance of this resistant S choleraesuis is a serious threat to public health, and thus constant surveillance is warranted.

Ceftriaxone↗
PubMed2002

Molecular epidemiology of nalidixic acid-resistant campylobacter isolates from humans and poultry by pulsed-field gel electrophoresis and flagellin gene analysis.

To investigate the potential of poultry products as the source of human infections associated with quinolone-resistant campylobacters, 140 human and 75 poultry isolates of nalidixic acid-resistant campylobacters were collected between 1996 and 1998, and analysed by two molecular typing methods. By the analysis of restriction fragment length polymorphism of the flagellin gene, 33 distinct patterns were obtained, with 18 of which shared by both human (89%) and poultry (93%) isolates. By the pulsed-field gel electrophoresis of SmaI-restricted macrofragments, 105 different profiles were obtained, and 11 were found in both human (40%) and poultry (23%) isolates. When the two typing methods were combined, 112 unique genotypes were obtained, 11 of which were shared by both populations, including 53 (38%) human isolates and 14 (19%) poultry isolates. Although domestic poultry products are still important sources of the quinolone-resistant campylobacter infections in humans, there are other factors that might contribute to these increasing infections simultaneously. A more stringent policy in the use of antimicrobial agents in food animals can no longer be ignored.

Animals↗
PubMed2002

Combined bronchoalveolar lavage and polymerase chain reaction in the diagnosis of pulmonary tuberculosis in smear-negative patients.

SETTING: The polymerase chain reaction (PCR) may be sensitive and specific for the diagnosis of tuberculosis, but most reports are of studies conducted in well-controlled laboratories. A study to evaluate the clinical value of bronchoalveolar lavage (BAL) combined with PCR was necessary. OBJECTIVE: One hundred and thirty one patients were recruited into the study from March 1994 to February 1997. DESIGN: Patients with a positive acid-fast stain on sputum smear were recruited into group A as positive controls, patients with lung cancer and a negative acid-fast stain on sputum smear were put into group B as negative controls, and patients who had clinical symptoms of pulmonary TB without sputum or with negative smear results were the investigating group. PCR was performed on the sputum samples from group A and B patients and on the BAL fluid from those in group C. RESULTS: The sensitivity of PCR was 96% in group A, and the specificity was 100% in group B. The sensitivity of PCR in the BAL fluid from the group C patients was 36% and the specificity was 96%; the positive predictive value was 94% and the negative predictive value was 45%. CONCLUSION: BAL plus PCR is useful in the rapid diagnosis of pulmonary TB in non-productive or smear-negative patients.

Bronchoalveolar Lavage Fluid↗
PubMed2001

Development of two ELISA for estrogen and progesterone receptor with sufficient sensitivity for fine needle aspirate and core biopsy.

The quantitative determination of estrogen and progesterone receptors (PR and ER) in breast tumor cytosol has been routinely performed in clinical laboratories to aid in the selection between hormonal and chemotherapy and also to predict prognosis. However, the small amount of tissue available from the increasingly popular fine-needle aspiration and core biopsies from breast cancer patients requires more sensitive immunoassays for receptor quantification. We have developed two sensitive immuno-assays for ER and PR on microplate with the use of recently available anti-ER and anti-PR antibodies of higher affinity and a powerful signal magnification agent, namely Amdex. The calibrator was a pooled breast tumor cytosol used as calibrator and calibrated against Abbott kits. The protein concentration of the cytosol and the upper normal cutoffs for our assays were reduced to approximately 0.2 mg/mL and 3 fmol/0.2 mg/mL, respectively. Both assays have sensitivities close to 1 fmol/mL, which are sufficiently sensitive for the receptor quantification in fine-needle aspiration biopsies and cord biopsies of breast tumor.

Antibodies, Monoclonal↗
PubMed2001

Characterization of serum and urinary chromogranin A by size exclusion chromatography: impact on calibrator selection and urinary assay.

Serum chromogranin A (CgA) is a useful marker for neuroendocrine tumors and is detectable in carcinomas at advanced stages. Elevated serum CgA is also an indicator of poor prognosis in prostate cancer and is useful for predicting the failure of hormonal therapy for prostate cancer patients. We found that CgA molecules with three different sizes could be detected in normal human serum. However, only the largest CgA molecule appears in patients with liver disease. Serum taken from cancer patients is composed predominantly of the middle-sized molecule, whereas the smallest CgA molecule was elevated in serum drawn from renal patients. Moreover, only the smallest CgA molecule was found in urine. We believe that the largest CgA molecule is metabolized by the liver, whereas the smallest CgA molecule is removed from the blood circulation via the kidney. Because the medium-sized CgA is the dominant molecule in both the cell medium of the tumor cell line SK-N-AS and sera from patients with malignant diseases, CgA from the cell medium was selected as the calibrator for the CgA ELISA assay. Our findings also suggest that it would not be possible to measure the urinary CgA to reflect the serum CgA concentration in order to detect pheochromocytoma among patients with hypertension.

Calibration↗
PubMed2001

Secular trends in incidence and antimicrobial resistance among clinical isolates of Salmonella at a university hospital in Taiwan, 1983-1999.

The incidence and antimicrobial resistance among clinical isolates of salmonella at a university hospital in Taiwan between 1983 and 1999 are summarized in this report. A total of 7986 isolates were analysed. Serogroup B has been the most prevalent over the years, with an apparently continuous decline after 1995. Concordant decrease was also found among S. choleraesuis and S. typhi isolates in recent years. In contrast, the proportion of serogroup D strains increased significantly after 1996. S. typhi remained relatively susceptible to most of the antimicrobial agents examined. For non-typhoidal isolates, antimicrobial resistance to ampicillin (62%), chloramphenicol (67%), and sulfamethoxazole-trimethoprim (37%) was relatively higher than that reported elsewhere. Newer generation cephalosporins and fluoroquinolones remained effective over the years, although emerging resistance to these drugs has been noticed since 1992. A more prudent selection and use of antimicrobial agents, in both humans and animals, and a continuous surveillance of resistance are essential in the future.

Drug Resistance, Microbial↗
PubMed2001

Real-time quantitative PCR analysis for alpha-thalassemia-1 of Southeast Asian type deletion in Taiwan.

Since homozygosity of the alpha-thalassemia-1 of Southeast Asian (SEA) type deletion results in hydrops fetalis, a novel protocol based on the real-time quantitating polymerase chain reaction (PCR) technique has been developed to quantify the intact and aberrant alpha-globin genes in adults. The ratio of the normal/SEA-bearing alpha-globin genes was expressed in cycle threshold (C(T)) values. Theoretically, a relative ratio of one to one was anticipated in individuals carrying the SEA type deletion. Twenty-five heterozygous and 20 normal cases were analyzed retrospectively with this protocol. Data showed that the CT values for the intact alpha-globin gene allele and the allele bearing the SEA type deletion in carriers were 28.74+/-1.49 and 26.46+/-2.05, respectively. Therefore, the ratio of normal/SEA type deletion-bearing alpha-globin genes in the carriers was 1.09+/-0.043. No ambiguous results were observed from other less common genotypes associated with alpha-thalassemia, such as the Philippine type deletion. Based on the results, we concluded that this protocol could provide a rapid method to mass screen carriers with alpha-thalassemia-1 of SEA type deletion in this region.

Alleles↗
PubMed2001

Multicenter surveillance of antimicrobial resistance of major bacterial pathogens in intensive care units in 2000 in Taiwan.

A susceptibility surveillance study of 1,274 bacterial isolates recovered from various clinical specimens from patients in intensive care units (ICUs) of five major teaching hospitals was carried out from March, 2000, to June, 2000, in Taiwan. This study demonstrated a high rate (66%) of oxacillin resistance in Staphylococcus aureus (ORSA), a high rate of nonsusceptibility to penicillin (intermediate, 50% and highly resistant, 8%), and high rates of cefotaxime nonsusceptibility for S. pneumoniae (intermediate, 29% and resistant, 4%), Enterobacter cloacae (57%), Serratia marcescens (34%), and Citrobacter freundii (60%). High rate of ceftazidime nonsusceptibility for Pseudomonas aeruginosa (22%), and high rates of imipenem nonsusceptibility for P. aeruginosa (15%) and Acinetobacter baumannii (22%) were also found. The percentage (11.9%) of extended-spectrum beta-lactamase (ESBL)-producing Escherichia coli was greater than that (11.3%) for Klebsiella pneumoniae. Rates of quinupristin-dalfopristin nonsusceptibility for S. pneumoniae (42%), Enterococcus faecium (71%), and ORSA (39%) were high, but no vancomycin-resistant enterococci were found in this study. The resistance rates of some pathogen varied by institution or type of ICUs. Surveillance for antimicrobial resistance among bacterial pathogens in hospitals, particularly in ICU settings with a preexisting higher resistance burden, is mandatory in establishing and/or modifying guidelines for empirical treatment of severe infections in ICU patients caused by these antimicrobial-resistant pathogens.

Bacteria↗
PubMed2001

Outer membrane protein change combined with co-existing TEM-1 and SHV-1 beta-lactamases lead to false identification of ESBL-producing Klebsiella pneumoniae.

Nine isolates of Klebsiella pneumoniae, obtained from one colonized and eight bacteraemic patients on a paediatric ward, were shown to be identical by PFGE, indicating an outbreak. Screening for extended-spectrum beta-lactamase (ESBL) production using the double-disc synergy test, Etest for ESBLs and agar diffusion tests indicated ESBL production. The isolates showed reduced susceptibility to cefotaxime but not to other third-generation cephalosporins. Molecular studies revealed production of TEM-1 and SHV-1 but no ESBLs were identified. Deficiency in expression of an outer membrane protein (OmpK35) was also observed. These observations led us to postulate that the extremely low level of OmpK35 expression and the co-existence of TEM-1 and SHV-1 resulted in an increased MIC of cefotaxime and the false designation of the isolates as ESBL producers. All the infected infants were treated with either third-generation cephalosporins alone or multiple antibiotics including a third-generation cephalosporin, and recovered and were discharged without sequelae.

Anti-Bacterial Agents↗
PubMed2001

Rapid identification of yeasts in positive blood cultures by a multiplex PCR method.

Yeasts are emerging as important etiological agents of nosocomial bloodstream infections. A multiplex PCR method was developed to rapidly identify clinically important yeasts that cause fungemia. The method amplified the internal transcribed spacer 1 (ITS1) region between the 18S and 5.8S rRNA genes and a specific DNA fragment within the ITS2 region of Candida albicans. With this method, C. albicans produced two amplicons, whereas other species produced only one. Through sequence analysis, the precise lengths of the PCR products were found to be as follows: C. glabrata (482 or 483 bp), C. guilliermondii (248 bp), C. parapsilosis (229 bp), C. albicans (218 or 219 and 110 bp), C. tropicalis (218 bp), Cryptococcus neoformans (201 bp), and C. krusei (182 bp). The PCR products could be effectively separated by disk polyacrylamide gel electrophoresis. The method was used to test 249 positive blood cultures (255 isolates), from which the following species (strain number) were isolated: C. albicans (128), C. tropicalis (51), C. glabrata (28), C. parapsilosis (23), C. neoformans (9), C. krusei (5), C. guilliermondii (3), and other, minor species (8). The test sensitivity of the method was 96.9% (247 of 255 isolates). The eight minor species were either misidentified (one strain) or not identified (seven strains). From the time at which a positive bottle was found, the multiplex PCR could be completed within 8 h; the present method is simpler than any previously reported molecular method for the identification of blood yeasts.

Blood↗
PubMed2001

Evaluation of Etest for direct antifungal susceptibility testing of yeasts in positive blood cultures.

The performance of the Etest (AB BIODISK, Solna, Sweden) for direct antifungal susceptibility testing of yeasts in positive blood cultures was compared with that of the macrodilution method for determining the MICs of five antifungal agents. Culture broths with blood from bottles positive for yeasts were inoculated directly onto plates for susceptibility testing with the Etest, and the MICs were read after 24 and 48 h of incubation. A total of 141 positive blood cultures (72 cultures of Candida albicans, 31 of Candida tropicalis, 14 of Candida glabrata, 11 of Candida parapsilosis, 3 of Candida krusei, and 3 of Cryptococcus neoformans, 4 miscellaneous yeast species, and 3 mixed cultures) were tested, and the rates of MIC agreement (+/-1 log(2) dilution) between the direct Etest (at 24 and 48 h, respectively) and macrodilution methods were as follows: amphotericin B, 81.8 and 93.5%; flucytosine, 84.8 and 87.7%; fluconazole, 89.4 and 85.5%; itraconazole, 69.7 and 63.8%; ketoconazole, 87.9 and 79.0%. By a large-sample t test, the difference in log(2) dilution between the direct Etest and the macrodilution method was found to be small (P < 0.05). The lone exceptions were ketoconazole at 48 h of incubation and itraconazole at both 24 and 48 h of incubation (P > 0.05). By Tukey's multiple comparisons, the difference between the direct Etest (48 h) and reference methods among different species was found to be less than 1 log(2) dilution. When the MICs were translated into interpretive susceptibility, the minor errors caused by the direct Etest (at 24 and 48 h, respectively) were as follows: flucytosine, 2.3 and 1.4%; fluconazole, 3.0 and 3.6%; itraconazole, 21.2 and 21.3%. Itraconazole also produced an additional 3.0 and 3.6% major errors as determined by the direct Etest at 24 and 48 h, respectively. It was concluded that, except for itraconazole, the Etest method was feasible for direct susceptibility testing of blood cultures positive for yeasts. The method is simple, and the results could be read between 24 and 48 h after direct inoculation, whenever the inhibition zones were discernible.

Antifungal Agents↗
PubMed2001

Liver abscess caused by Klebsiella pneumoniae in siblings.

Klebsiella pneumoniae has been emerging as the leading cause of liver abscess in diabetic patients. Results of molecular typing of K. pneumoniae isolates from two siblings with liver abscess, their family members, and the environment suggest a possibility of cross infection of liver abscess by the fecal-oral route within diabetic patients.

Adolescent↗
PubMed2001

Guiding mode expansion of a TE and TM transverse-mode integral equation for dielectric slab waveguides with an abrupt termination.

We propose a rigorous transverse-mode integral equation formulation for analyzing TE and TM electromagnetic radiation fields on the facet of dielectric slab waveguides with an abrupt termination in free space. Both exact waveguide guiding modes and discretized radiation modes are included in the kernels of the integral equation. To reduce the size of the matrix that approximates the exact integral equation, we expand the unknown field at the junctions in terms of guiding modes of a selected waveguide with sufficiently large normalized frequency and core thickness. By direct matrix inversion, we obtain numerical solutions of the scattered fields at the junctions. Our method can be used to study the field distribution as well as the energy reflection and transmission coefficients of dielectric waveguides with multiple step discontinuities.

Journal Article↗
PubMed2001

Outbreaks of nosocomial bloodstream infections associated with multiresistant Klebsiella pneumoniae in a pediatric intensive care unit.

BACKGROUND: Between June and October 1997, and during April 1998, a cluster of nosocomial bloodstream infections (BSIs) associated with Klebsiella pneumoniae was observed in 8 premature neonates from 1 pediatric intensive care unit (TPICU) in a 4000-bed medical center in northern Taiwan. An investigation was conducted to identify the possible reservoirs and mode of transmission. METHODS: Epidemiologic surveillance and infection control interventions were executed. The environment was checked by submitting several swab samples for microbiological studies. The antibiograms and results from 2 molecular typing methods (pulsed-field gel electrophoresis and infrequent-restriction site polymerase chain reaction) of all bacteremic and environmental isolates of K. pneumoniae were compared. RESULTS: Totally 39 K. pneumoniae isolates, including 9 from bacteremia, 26 from the environment, and 4 controls, were analyzed. One major pattern was found in 21 isolates, which included 8 bacteremic isolates with identical antibiograms, a single isolate from rectal swab screening, 2 of 8 isolates from hand cultures of medical staff, and 10 of 17 isolates from swabs of sinks in the TPICU. All 21 isolates illustrated identical antibiograms, while the other 18 isolates shared 4 antibiograms and 15 unique patterns. CONCLUSIONS: The nosocomial BSIs appeared to be an outbreak induced by 1 multiresistant K. pneumoniae strain. The sinks may have acted as reservoirs for this outbreak strain. During washing, splattered water droplets containing the bacterial particles may have contaminated the hands of medical personnel and were then further transmitted to patients.

Bacteremia↗