Biomedical subjects

H Y Tsai

Publications and source records attributed to H Y Tsai.

At least 19 recordsLinked to original sources

PubMed2006

Separation method based on affinity reaction between magnetic and nonmagnetic particles for the analysis of particles and biomolecules.

A separation method is reported for particle and biochemical analysis based on affinity interactions between particle surfaces under magnetic field. In this method, magnetic particles with immunoglobulin G (IgG) or streptavidin on the surface are flowed through a separation channel to form a deposition matrix for selectively capturing nonmagnetic analytes with protein A or biotin on the surface due to specific antigen (Ag)--antibody (Ab) interactions. This separation method was demonstrated using model reactions of IgG--protein A and streptavidin-biotin on particle surface. The features of this new separation method are (1) the deposited Ag-Ab complex can be examined and further analyzed under the microscope, (2) a kinetic study of complex binding is possible, and (3) the predeposited matrix can be formed selectively and changed easily. The detection limits were about 10(-11) g. The running time was less than 10 min. The selectivities of studied particles were 94% higher than those of label-controlled particles. This method extends the applications of analytical magnetapheresis to nonmagnetic particles. Preliminary study shows that this separation method has a great potential to provide a simple, fast, and selective analysis for particles, blood cells, and immunoassay related applications.

Biotin↗

PubMed2006

Solid-phase microextraction coupled with liquid chromatography for determination of beta-carotene in food.

Beta-carotene in vegetables and nutritional products is analyzed using solid-phase microextraction (SPME) coupled with liquid chromatography (LC) to improve the speed of analysis and to reduce the consumption of organic solvents. The relative standard deviations (RSDs) of this analytical method for beta-carotene determinations in vegetables and nutritional products are approximately 10% and 5%, respectively. The amount of beta-carotene was found to vary from 0.35 +/- 0.05 ppm to 76.5 +/- 6.9 ppm for several vegetables in Taiwan. This method was linear over the range of 0.4-40 ppm with correlation coefficients higher than 0.997. The experimentally determined level of beta-carotene in nutritional products varied from 3.8 +/- 0.2 ppm to 24.6 +/- 1.1 ppm following SPME-LC. The recoveries of beta-carotene for these measurements following SPME were all higher than 97% +/- 2% (n = 3). The detection limits of beta-carotene for this method were from 0.027 to 0.054 ppm. Conventional solvent extractions take approximately 4-6 h for extraction and reconcentration but SPME takes approximately 1 h. From several tens to hundreds of milliliters, organic solvents can be saved using SPME. SPME provides better analyses on beta-carotene than conventional solvent extraction for nutritional products in terms of speed, precision, simplicity, and solvent consumption.

Beverages↗

PubMed2005

New method of blood typing using analytical magnetapheresis.

We report a new method of blood typing based on the agglutination of red blood cell (RBC) with serum-treated magnetic particles in analytical magnetapheresis. Blood typing of ABO was demonstrated. The agglutination patterns of RBCs are different for different blood types and can be used to determine the ABO blood typing in analytical magnetapheresis. Six samples can be tested in each run. The running time was less than 10 min. Magnetic particles were prepared in the laboratory. The amount of RBCs needed for the agglutination test was about 1.0 microl of adult blood. The blood typing of ABO was used to illustrate the capable applications of analytical magnetapheresis to nonmagnetic samples like cells without magnetic labels. Analytical magnetapheresis has a great potential for cell related analysis.

ABO Blood-Group System↗

PubMed2005

Impurity analysis of 1,4-dioxane in nonionic surfactants and cosmetics using headspace solid-phase microextraction coupled with gas chromatography and gas chromatography-mass spectrometry.

1,4-Dioxane impurity in nonionic surfactants and cosmetics were analyzed using solid-phase microextraction (SPME) coupled with gas chromatography (GC) and gas chromatography-mass spectrometry (GC-MS). Experimental results show that there is no significant difference using SPME-GC and SPME-GC-MS for analysis of 1,4-dioxane in three types of nonionic surfactants at the 95% confidence level. The relative standard deviation (R.S.D.) values of each analytical method were smaller than 3%. The amount of 1,4-dioxane was found to vary from 11.6 +/- 0.3 ppm to 73.5 +/- 0.5 ppm in 30% of nonionic surfactants from manufacturers in Taiwan. These methods were linear over the studied range of 3-150 ppm with correlation coefficients higher than 0.995. The recoveries of 1,4-dioxane for these nonionic surfactants following SPME were all higher than 96 +/- 1% (n = 3). The detection limits of 1,4-dioxane for these nonionic surfactants following SPME were from 0.06 ppm to 0.51 ppm. The experimentally determined level of 1,4-dioxane in cosmetics from manufacturers in Taiwan varied from 4.2 +/- 0.1 ppm to 41.1 +/- 0.6 ppm in 22% of daily used cosmetics following SPME coupled with GC and GC-MS. Conventional solvent extraction takes around 1 h for extraction and reconcentration but SPME takes only around 10 min. SPME provides better analyses of 1,4-dioxane in nonionic surfactants and cosmetics than conventional solvent extraction and head space pretreatments in term of simplicity, speed, precision, detection limit, and solvent consumption.

Calibration↗

PubMed2004

Determination of magnetic susceptibility of various ion-labeled red blood cells by means of analytical magnetapheresis.

Analytical magnetapheresis is a newly developed technique for separating magnetically susceptible particles. The magnetically susceptible particles are deposited on a bottom plate after flowing through a thin (< 0.05 cm) separation channel under a magnetic field applied perpendicular to the flow. Particles with various magnetic susceptibilities can be selectively deposited and separated by adjusting the applying magnetic force and flow rates. Magnetic susceptibility is an important parameter for magnetic separation. Magnetic susceptibility determination of various ion-labeled red blood cells (RBCs) using analytical magnetapheresis with a simple theoretical treatment is reported in this study. Susceptibility determination is based on the balance between maximal channel flow rate and magnetically induced flow rate for deposition. We tried a new approach to determine particle magnetic susceptibilities using a balance of magnetic and drag forces to control magnetically induced particle velocities. The Er3+, Fe3+, Cu2+, Mn2+, Co2+, and Ni2+ ions were used to label RBC at various labeling concentrations for susceptibility determination. The susceptibilities determined for various ion-labeled RBC under two magnetic field intensities fell within a 10% range. The average viabilities of various ion-labeled RBCs were 96.1 +/- 0.8%. The susceptibility determination generally took less than 10 min. Determined susceptibilities from analytical magnetapheresis differed by 10% from reference measurements using a superconducting quantum interference device (SQUID) magnetometer. The cost and time for analysis is much less using analytical magnetapheresis. This technique can provide a simple, fast, and economical way for particle susceptibility determinations.

Cations↗

PubMed2003

Dose reconstruction for residents living in buildings with moderate and minor 60Co contamination in rebar.

Previously, we have reconstructed cohort dependent individual doses for residents living in rebar buildings of high 60Co contamination. These reconstructions were carried out using intensively collected TLD data on exposure rates at locations of 1 m height and 1 m x 1 m intersections. The present work deals with dose reconstructions for residents living in rebar buildings of moderate and minor 60Co contamination. Since only limited data on exposure rates from survey meters were available, dose reconstructions were based on these data using interpolations. To utilize such data, we examined them with respect to all factors that influenced the dose uncertainties. The interpolated results were given in terms of contour plots (isodose curves) and compared with corresponding results derived from TLD data and Monte Carlo simulations. The comparison revealed that survey meter data could be used to provide reasonable and conservative estimates of residential doses. By applying the cohort-dependent room occupancy factor and the site-dependent area occupancy factor, we reconstructed cohort dependent individual doses and associated uncertainties. Results of dose reconstructions for all residents living in contaminated rebar buildings were provided to the Atomic Energy Council and health authorities for epidemiologic and medical uses.

Air Pollution, Indoor↗

PubMed2003

Analyses and applications of single scan dose profiles in computed tomography.

Comprehensive analyses and measurements of computed tomography (CT) single-scan dose profiles were performed for several scanners and operating conditions. Measurements were made using two types of thermoluminescent dosimeters, LiF:Mg,Cu,P and CaSO4:Dy, and two CT dosimetry phantoms, head and body. Analyses of CT single-scan dose profiles were made in terms of a Gaussian function for primary radiation and a Lorentzian function for scattered radiation. This function was used to investigate several common descriptions of the CT dose, including the computed tomography dose index (CTDI) and the multiple scan average dose. The relative percentage of scatter versus primary radiation to the contribution of CTDI at the central and peripheral locations was determined and analyzed. The correlation between CTDI of thermoluminescent dosimeter measurements and pencil-shaped ionization chamber measurements was determined. A method for estimating organ dose from CT was developed and compared to organ-dose estimates from Monte Carlo simulations.

Head↗

PubMed2002

Effects of veratrine and paeoniflorin on isolated mouse vas deferens.

In this study, we attempted to identify the interactions and mechanisms between veratrine and paeoniflorin on isolated mouse vas deferens. Paeoniflorin had no effect on isolated mouse vas deferens. Veratrine (1 x 10(-5) approximately 1 x 10(-3) g/ml) could directly induce contraction of isolated rat and mouse vas deferens. The concentration induced by veratrine (1 x 10(-5) g/ml) was completely inhibited by Ca2+-free solution and verapamil (1 x 10(-5) M), in both the epididymal and the prostatic portions of isolated mouse vas deferens. Naloxone (1 x 10(-5) M) did not alter the contraction induced by veratrine (1 x 10(-5) g/ml) in either the epididymal or the prostatic portions of isolated mouse vas deferens. Paeoniflorin (4.8 x 10(-5) g/ml) inhibited the contraction induced by veratrine (1 x 10(-5) g/ml) in both the epididymal and the prostatic portions of isolated mouse vas deferens. Paeoniflorin (4.8 x 10(-5) g/ml) potentiated norepinephrine (1 x 10(-5) M)-induced phasic contraction in the epididymal portion, but decreased contractions in the prostatic portion. Paeoniflorin (4.8 x 10(-5) g/ml) increased KCI (56 mM)-induced phasic contraction in the epididymal portion, but decreased the tonic contraction in either the epididymal or the prostatic portion. Veratrine (1 x 10(-5) g/ml)-induced contractions could be decreased by pretreatment with ryanodine (1 x 10(-5) M) in both the epididymal and the prostatic portions. Pretreatment with the combination of paeoniflorin (4.8 x 10(-5) g/ml) and ryanodine (1 x 10(-5) M) did not potentiate the inhibition of paeoniflorin in the veratrine-induced contraction in both the epididymal and the prostatic portions of isolated mouse vas deferens.

Animals↗

PubMed2001

Effects of paeoniflorin on the formalin-induced nociceptive behaviour in mice.

In this study, we attempted to identify the mechanisms of paeoniflorin on antinociceptive effects in mice. Paeoniflorin (48, 96, 240, 480 microg, i.c.v.) showed dose-related antinociception both on the early and late phases of formalin test in mice. Moreover, paeoniflorin (48 microg, i.c.v.) could potentiate the antinociception of morphrine (0.5, 1.0 mg/kg, s.c.) in the formalin test. However, the antinociceptive effects of paeoniflorin were not potentiated by L-arginine (600 mg/kg, i.p.) or antagonized by beta-funaltrexamine (beta-FNA) (10 microg, i.c.v.), ICI-174,864 (1 microg, i.c.v.) and ryanodine (10 ng, i.c.v.) on both the early and late phases of formalin test. L-NAME (75 mg/kg, i.p.) could reverse the effect of paeoniflorin on the late phase of formalin test. Naloxone (1 mg/kg, i.p.) and nor-binaltorphimine (nor-BNI) (1 microg, i.c.v.) could block the paeoniflorin-induced antinociception on the early phase of formalin test. These results suggested that the central antinociceptive effects of paeoniflorin on formalin test in mice were mediated by the activation of kappa-opioid receptor and not related to the increase of intracellular calcium.

Animals↗

PubMed2001

Determination of guidance levels of dose for diagnostic radiography in Taiwan.

The International Atomic Energy Agency has recommended guidance levels of dose for diagnostic radiography for a typical adult patient. These levels were intended to act as thresholds to trigger investigations or corrective actions in ensuring optimized protection of patients and maintaining appropriate levels of good practice. Since guidance levels should be derived from wide scale surveys of exposure factors performed in individual hospitals, a national survey was conducted recently in Taiwan to collect these factors for the most frequent radiographic procedures. A total of 276 completed questionnaires were received and analyzed. In the questionnaire, respondents were asked to check those projections that were routinely performed in their department and to report machine data, patient data, output measurements, and technical factors including kVp, mAs, focus-to-film distance, table-to-film distance, aluminum filtration, and focal spot size. Based on the survey data, entrance skin exposures in air, i.e., free air exposures at the point of intersection of the x-ray central beam with the entrance surface of the patient, were estimated using the RADCOMP program. Entrance surface doses to air and tissue with backscatter were then evaluated by the application of the exposure-dose conversion factor and the backscatter factor obtained from TLD measurements and Monte Carlo simulations. Guidance levels were determined from survey results on the entrance surface dose based on optimization considerations involving the cost-effectiveness analysis. Except for chest PA and LAT and skull LAT procedures, all guidance levels derived in this work are less than those recommended by the International Atomic Energy Agency. Survey data and guidance levels were provided to the national authorities to help them develop quality control and radiation protection programs for medical exposures.

Humans↗

PubMed2001

Ellagic acid inhibited 2-aminofluorene and p-aminobenzoic acid acetylation by mononuclear leucocytes from Sprague-Dawley rats.

Following exposure of rats to the arylamine carcinogen 2-aminofluorene, DNA-carcinogen adducts were found in the liver and bladder target tissues, and also in circulating leucocytes. This work investigated the effect of ellagic acid on arylamine (2-aminofluorene and p-aminobenzoic acid) acetylations in rat leucocytes. Evidence is presented that rat mononuclear leucocytes are capable of acetylating 2-aminofluorene and p-aminobenzoic acid. Both lymphocytes and monocytes were able to acetylate arylamines during 18 h of culture. Cultured lymphocytes produced about twice as much N-acetyl-2-aminofluorene from 2-aminofluorene and 2.2-fold as much N-acetyl-p-aminobenzoic acid from p-aminobenzoic acid as monocytes. After cotreatment with ellagic acid the lymphocyte and monocyte cultures indicated that ellagic acid reduced 2-aminofluorene acetylation.

4-Aminobenzoic Acid↗

PubMed2000

Bacteremic pneumonia caused by a single clone of Streptococcus pneumoniae with different optochin susceptibilities.

Two isolates of Streptococcus pneumoniae having different optochin susceptibilities were recovered from a blood sample of a 2-year-old boy with community-acquired pneumonia. The two isolates were documented to belong to a single clone on the basis of the isolates' identical serotype (23F), antibiograms by the E-test, random amplified polymorphic DNA patterns generated by arbitrarily primed PCR, pulsed-field gel electrophoresis, and restriction fragment length polymorphism of the penicillin-binding protein genes pbp2b and pbp2x.

Bacteremia↗

PubMed1999

Effects of veratrine and paeoniflorin on the isolated rat aorta.

The interactions and mechanisms between veratrine and paeoniflorin on the isolated rat aorta were studied. Veratrine (1x10(-6) to 1x10(-4) g/ml) could induce contraction on the isolated rat aorta in a concentration-related manner. Paeoniflorin had no effect on the isolated rat aorta. Pretreatment with prazosin (1x10(-6) M) and nifedipine (1x10(-6) M) but not yohimbine (1x10(-5) M) could decrease the tension of contraction induced by veratrine (1x10(-4) g/ml). Sodium nitroprusside (1x10(-4) M) could inhibit the contraction induced by veratrine (1x10(-4) g/ml) with or without endothelium, whereas methylene blue (5x10(-5) M) could increase the contraction induced by veratrine (1x10(-4) g/ml). Treatment with veratrine (1x10(-4) g/ml) could decrease the tension of contraction induced by norepinephrine (1x10(-6) M) or phenylephrine (1x10(-4) M). The inhibition of veratrine on norepinephrine-induced contraction was potentiated by L-arginine (1x10(-4) M) and reversed by L-NAME (1x10(-5) M). Paeoniflorin (1x10(-4) M) could decrease the tension of contraction induced by veratrine (1x10(-4) g/ml) and methylene blue (5x10(-5) M). The inhibition of paeoniflorin on veratrine was more potent on rat isolated aorta with endothelium than without endothelium. Ryanodine (1x10(-5) M) and Ca2+ -free medium could inhibit methylene blue-induced contraction. From the above results, the relaxation of veratrine on the norepinephrine-induced contraction might be related to the increase of NO and cGMP. The contraction of veratrine on the isolated rat aorta was via the increase of intracellular calcium which was inhibited by paeoniflorin.

Animals↗

PubMed1999

Immunogenicity and safety of standard-titer AIK-C measles vaccine in nine-month-old infants.

Because of the interference by maternal antibody before 1 year of age, the Schwarz strain of measles vaccine, which has been routinely used in Taiwan, must be given at 9 months and 15 months of age to ensure an optimal immune response. The AIK-C strain of measles vaccine has been reported to be highly immunogenic. This study evaluated the immunogenicity and safety of the AIK-C vaccine in 9-month-old Taiwanese infants. A total of 135 infants were recruited and were randomly assigned to receive either Schwarz vaccine (68 cases) or AIK-C vaccine (67 cases). Measles antibodies were assayed before and 1 month after the vaccination. Sixty-five (97%) infants who received the AIK-C vaccine seroconverted after the vaccination, whereas the seroconversion rate in those receiving the Schwarz vaccine was 77% (P = 0.001). The incidences of adverse reactions were comparable between the two groups. We conclude that even in 1990s, the failure rate of Schwarz vaccine in 9-month-old infants is still high. The AIK-C vaccine is more immunogenic in infants and its long-term immunogenicity and safety deserve further evaluation.

Antibodies, Viral↗

PubMed1999

Evaluations of gonad and fetal doses for diagnostic radiology.

A national survey of patient doses for diagnostic radiology was planned in the Republic of China. We performed a pilot study for this survey to develop a protocol of the dose assessments. Entrance skin doses and organ (including ovary, testicle and uterus) doses were measured by thermoluminescent dosimeters and calculated by means of Monte Carlo simulations for several diagnostic procedures. We derived a formula and used the RadComp software for the computation of entrance skin doses. This formula involves several factors, such as kVp, mAs, the focus-to-skin-distance and aluminum filtration. RadComp software was applied to obtain free-air entrance exposures which were converted to entrance skin doses by considering the backscattering radiation from the body. Organ doses were measured using a RANDO phantom and calculated using a mathematical phantom for several diagnostic examinations. Genetically significant doses were calculated from ovary and testicle doses for the evaluation of hereditary effects. Embryo/fetal doses were determined from the uterine doses by considering the increase in uterus size with gestational age. We found that the patient doses studied in this work were all below the reference doses recommended by the National Radiological Protection Board of the U.K.

Algorithms↗

PubMed1999

Immunogenicity of oral poliovirus vaccine in Taiwan.

Previous studies have shown that the immune response to trivalent oral poliovirus vaccine (OPV) varies widely from country to country. However, there has been no report on the immunogenicity of this vaccine in Taiwanese children. In this study, 98 children were followed up for 17 months to study the antibody responses following four doses of trivalent OPV. The results showed that, after two doses of vaccine, all children were protected against poliovirus type 1 and 2. All except two children also developed protective antibodies against poliovirus type 3. After three doses, the antibody levels in all subjects were above protective concentrations. The fourth dose, given at 18 months of age, further boosted the antibody titers. These findings show that the OPV currently used in Taiwan is highly immunogenic in Taiwanese children.

Antibodies, Viral↗

PubMed1998

Effects of aspirin on arylamine N-acetyltransferase activity in Klebsiella pneumoniae.

This study was designed to assess the effects of aspirin on arylamine N-acetyltransferase (NAT) activities in the bacterium Klebsiella pneumoniae using high performance liquid chromatography to measure the acetylation of 2-aminofluorene (2-AF) with or without aspirin. Cytosols or suspensions of K. pneumoniae with or without specific concentrations of aspirin co-treatment showed different percentages of 2-AF acetylation. The data indicated that there was decreased NAT activity associated with increased levels of aspirin in K. pneumoniae cytosols and in intact bacteria. For the cytosol examination, the apparent values of Km and Vmax decreased 0.59- and 0.58-fold after co-treated with 40 microM aspirin, respectively, for 2-AF. For the intact bacteria examination, the apparent values of Km and Vmax decreased 0.60- and 0.67-fold after co-treated with 40 microM aspirin, respectively, for 2-AF. This report is the first demonstration to show that aspirin can decrease N-acetyltransferase activity in the bacterium K. pneumoniae.

Acetylation↗

PubMed1998

Comparison of once daily cefpodoxime proxetil suspension and thrice daily cefaclor suspension in the treatment of acute otitis media in children.

An open-labeled and randomized trial was conducted to compare the efficacy and safety of once daily cefpodoxime proxetil suspension (10mg/kg/day) and thrice daily cefaclor (45mg/kg/day) in the treatment of acute otitis media in children. A total of 57 children aged from 6 months to 9 years were enrolled; 23 were treated with cefpodoxime and 34 with cefaclor. Satisfactory clinical outcome, either cure or improvement, was achieved at the end of treatment in 90% of patients in the cefaclor group and 95% of patients in the cefpodoxime group (p > 0.05). Clinical recurrence was identified at the follow-up visits in one case of the cefaclor group (3%), and none in the cefpodoxime group (p > 0.05). These drugs were well tolerated by 14/21 (67%) in the cefpodoxime-treated group and 27/32 (84%) in the cefaclor-treated group. The incidence of adverse events was slightly higher in the cefpodoxime group than in the cefaclor group, however the difference did not reach statistical significance (p > 0.05). The daily cost of once-daily cefpodoxime was lower than that of thrice-daily cefaclor. We conclude that cefpodoxime administered once daily is as effective and safe as cefaclor administered thrice daily in the treatment of acute otitis media in children. The less dosing frequency and lower daily price of cefpodoxime provide additional benefits.

Acute Disease↗